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  • 1965-1969  (23,932)
  • Chemistry  (23,845)
  • Cat  (55)
  • Electron Microscopy  (32)
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  • 1
    Electronic Resource
    Electronic Resource
    Die Bestimmung der intestinalen Resorption von Herzglykosiden durch Messung der3H-markierten Glykoside im Portalvenenblut und in der Darmlymphe bei Katzen (1969)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 264 (1969), S. 406-419 
    Details
    ISSN: 1432-1912
    Keywords: Intestinal Absorption ; Cardiac Glycosides ; Blood of Portal Vein ; Intestinal Lymph ; Cat ; Intestinale Resorption ; Herzglykoside ; Portalvenenblut ; Darmlymphe ; Katze
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. The cardiac glyoosides digitoxin, ouabain, digoxin and peruvosid labelled with3H were injected into tied intestinal loops of anaesthetized cats in situ. The absorbed glycosides were measured in the blood of the portal vein and in the intestinal lymph. At the same time the3H-activity was measured in the blood of the peripheral circulation, in the bile and in the urine. 2. Calculation of the amount of glycosides totally absorbed from the3H-concentration in the blood of the portal vein and the circulation volume (bubble-flow-meter) gave the following absorption rates as a percentage of the administered dose per hour: digitoxin 56%, digoxin 42%, peruvosid 26% and ouabain 10%. 3. The amount of glycosides passing into the lymph during 1 hour was found to be only 0.006 to 0.02% of the amount offered. In lymph3H-activity cannot be measured earlier than 5 min after the administration of the labelled glycosides. The3H-concentration in the lymph did not equal that measured in the blood of the peripheral circulation until at least 1 hour after the administration and always remained below the3H-concentration of the blood in the portal vein. This proportion remained unchanged even if digitoxin was administered as an emulsion in oil instead of an aqueous solution. From the time course of3H-concentration it might be concluded that the glycosides do not pass directly to the lymph after absorption but indirectly by way of the blood. 4. The amount of glycoside excreted in the bile is for peruvosid 15,5% of the amount absorbed, for ouabain 1,9%, for digoxin 1,4% and for digitoxin 0,8%. The3H-activity excreted in urine is very small and can be disregarded. 5. Chromatographic analyses of the bile revealed, that in the case of digoxin, 4/5 of the amount excreted were unchanged, in the case of digitoxin and ouabain 2/3 and in the case of peruvosid only 1/4. In the lumen of the tied intestinal loops and in the tissue of the small intestine the glycosides were hardly metabolised.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01002379
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  • 2
    Electronic Resource
    Electronic Resource
    Verbesserung der Resorption von Helveticosid und Helveticosol durch Substitution der Hydroxylwasserstoffe an der Digitoxose (1969)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 262 (1969), S. 73-86 
    Details
    ISSN: 1432-1912
    Keywords: Strophanthidine Derivatives ; Toxicity ; Absorption ; Guinea-Pig ; Cat ; Strophanthidinderivate ; Toxicität ; Resorption ; Meerschweinchen ; Katze
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wurde die Wirksamkeit verschiedener Ester und Äther von Helveticosid und Helveticosol bei i.v. und intraduodenaler Zufuhr an Katzen und Meerschweinchen geprüft. 1. Bei i.v. Dauerinfusion waren Helveticosol und seine Derivate bei Meerschweinchen etwa doppelt so wirksam wie die analogen Helveticosidverbindungen. Bei der Katze bestand kein Unterschied. Die Monomethyläther Cymarin und Cymarol waren gleich oder sogar stärker wirksam, alle übrigen Derivate deutlich schwächer als die Ausgangssubstanzen. 2. Die tödlichen Dosen bei intraduodenaler Injektion lagen beim Meerschweinchen für einige Substanzen in gleicher Größenordnung oder niedriger als die Titer bei i.v. Infusion. Diese hohe enterale Wirksamkeit kann bei Helveticosid und seinen Derivaten durch eine Reduktion zu dem wirksameren Helveticosol, bei Estern außerdem durch eine Hydrolyse zu wirksameren Glykosiden vorgetäuscht werden. 3. Bei intraduodenaler Infusion an Katzen waren alle geprüften Ester und Äther wirksamer als Helveticosid und Helveticosol. Die aus dem Verhältnis der toxischen Dosen bei i.v. und intraduodenaler Infusion berechnete enterale Wirksamkeit lag zwischen 20 und 50%. 4. Unterschiede in der Dauer der intraduodenalen Infusion bei Katzen lassen sich berücksichtigen, wenn man von der theoretischen Annahme einer exponentiellen und vollständigen Resorption ausgeht und die Halbwertszeit für die Resorption berechnet. Die minimale Resorptionsgeschwindigkeit lag bei einigen Derivaten in gleicher Größenordnung wie bei Digoxin und Digitoxin. Es wird auf den Unterschied zwischen der auf Grund der pharmakologischen Wirkung bestimmten relativen enteralen Wirksamkeit und der Resorptionsquote hingewiesen. Letztere ist für die Verläßlichkeit der therapeutischen Wirkung eines Glykosids bei oraler Gabe maßgebend.
    Notes: Summary The efficacy of several esters and ethers of Helveticosid and Helveticosol was assayed by intravenous and intraduodenal administration to cats and guinea-pigs. 1. In guinea-pigs, Helveticosol and its derivatives were approximately twice as active on intravenous infusion as the analogous derivatives of Helveticosid; in cats there was no significant difference. The monomethylethers Cymarin and Cymarol were equally or slightly more potent, all other derivatives were weaker than the original compound. 2. In guinea-pigs the lethal doses of some compounds on intraduodenal injection were equal to or even lower than those on intravenous infusion. This may partly be accounted for by a reduction of Helveticosid and its derivatives to the more potent Helveticosol analogues, partly by a hydrolysis of the esters, yielding compounds of higher activity. 3. On intraduodenal infusion in cats, all the investigated esters and ethers were more active than Helveticosid and Helveticosol. The relative enteral activity calculated from the ratio of the toxic doses on intravenous and intraduodenal infusion varied between 20 and 50%. 4. Due to a delayed absorption from the gastrointestinal tract, the toxic dose falls with a reduced speed of intraduodenal infusion. Assuming an exponential and complete absorption, the half time of absorption was calculated. For some of the compounds investigated, the speed of absorption was comparable to that of Digoxin and Digitoxin. The difference between the relative enteral activities determined by comparing equiactive doses on enteral and parenteral administration and the percentages of the glycosides which are absorbed from the gastrointestinal tract is pointed out. The latter is of prime importance for obtaining reproducible effects after enteral administration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00536819
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  • 3
    Electronic Resource
    Electronic Resource
    Quantitative Untersuchungen an Gliazellen im Corpus callosum wachsender Katzen nach Perfusions- und Immersionsfixierung (1969)
    Springer
    Anatomy and embryology 128 (1969), S. 222-234 
    Details
    ISSN: 1432-0568
    Keywords: Postnatal development ; Fixation ; Neuroglia ; Corpus callosum ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Gehirne von Tieren aus 4 verschieden alten Würfen junger Katzen wurden teils lebensfrisch durch Perfusion, teils nach 24 Std durch Immersion fixiert und für Vergleichsuntersuchungen in Paraffin eingebettet. Bei Betrachtung der Gliazellen des Corpus callosum ergab sich: 1. Nach Perfusionsfixierung sind die Kerne der Gliazellen groß und elliptisch. Sie sind wasserklar und haben eine scharf gezeichnete Chromatinstruktur. Nach Immersionsfixierung 24 Std p.m. sind die Kerne dagegen klein und rund, homogen dunkel gefärbt und haben ein kaum zu erkennendes Chromatingerüst. 2. Nach Perfusionsfixierung sieht man im Balken der ganz jungen Tiere zahlreiche Mitosen. Sie fehlen bei den durch Immersion fixierten Geschwistertieren desselben Wurfes. 3. Die nach verschiedener Fixierung beobachteten Unterschiede in der Form der Gliazellkerne werden durch Messungen der Quer- und Längsachsen erfaßt.
    Notes: Summary In four litters of young cats, some of the brains were fixed by perfusion and the others by immersion. The material was embedded in paraffin and the neuroglia was investigated in sections through the corpus callosum. It was found that: 1. After fixation by perfusion the nuclei of the glia cells are large and elliptic. The caryoplasm is clear and there is a distinct structure of the chromatin. After fixation by immersion the nuclei of the same cells are small and round. The caryoplasm is dense and the structure of the chromatin is not clearly visible. 2. After fixation by perfusion mitotic figures are present. They are absent in the brains fixed by immersion. 3. Following different fixation, there are differences in the shape of the nuclei of the glial cells. These differences have been investigated in detail by measuring the diameters of the nuclei.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00521281
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  • 4
    Electronic Resource
    Electronic Resource
    Über die Gefäßversorgung des Corpus callosum der Katze (1969)
    Springer
    Anatomy and embryology 128 (1969), S. 28-39 
    Details
    ISSN: 1432-0568
    Keywords: Arterial supply ; Corpus callosum ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung An 27 Katzen beiderlei Geschlechts wurde die Blutversorgung des Corpus callosum untersucht. Dabei wurden folgende Befunde erhoben: Der Balken der Katze wird im Bereich des Rostrum und Genu sowie im vorderen und mittleren Truncuabschnitt aus der Arteria cerebri anterior versorgt und zwar über Äste, die den Arteriae pericallosae und den Arteriae genu corporis callosi entstammen. Diese Äste wurden als Arteriae callosi superiores und inferiores bezeichnet. Lediglich im hinteren Truncusabschnitt und im Splenium erfolgt die Versorgung neben Ästen der A. pericall. auch über solche der Arteriae cerebri mediae und posteriores. Die Blutgefäße treten dolchartig in den Balken ein, teilen sich dann baumartig weiter auf und gehen in ein Capillarnetz über, das in Richtung des Nervenfaserverlaufes ausgezogen ist. Auf in der Literatur bereits bekannte, aber oft vernachlässigte Besonderheiten der Arteria carotis interna und des Circulus arteriosus wird hingewiesen.
    Notes: Summary In investigations on 27 cats of both sexes, the arterial supply of the corpus callosum was studied. The findings are as follows: In the region comprising rostrum and genu as well as in the fore and middle trunk sections, blood supplied by branches of the arteriae pericallosae and the arteriae genu corporis callosi which originate from the arteria cerebri anterior. These branches were designated arteriae callosi superiores and inferiores. However, in the posterior section of the trunk and in the splenium the blood is supplied by branches of the aa. pericall. and, in addition, by branches of the arteriae cerebri media and posteriores. The blood vessels penetrate the corpus callosum in bayonet fashion, then arborise and finally become a capillary network which is elongated in the direction of the course of the nerve fibres. Attention is drawn to peculiarities of the arteria carotis interna and the circle of Willis which, although known in the literature, are rarely referred to.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00522492
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  • 5
    Electronic Resource
    Electronic Resource
    Étude d'une nouvelle observation de «Nemaline Myopathy» (1969)
    Springer
    Acta neuropathologica 13 (1969), S. 250-266 
    Details
    ISSN: 1432-0533
    Keywords: Electron Microscopy ; Congenital Myopathy ; Nemaline Myopathy ; Z-band Structure ; Sarcoplasmic Masses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé L'étude ultrastructurale d'une observation de «Nemaline-Myopathy» a été centrée sur les rapports structurels entre bâtonnets et stries Z normales dans différentes conditions de fixation. L'aspect des stries Z, en section transversale, varie en effet avec la fixation: réseau de ponts «obliques» (par rapport à l'alignement quadratique régulier des terminaisons des filaments fins) après fixation osmiée, réseau de ponts «transversaux», isolé ou superposé au premier réseau, après fixation aldéhydique initiale. L'aspect des bâtonnets en section transversale varie également avec la fixation; la disposition quadratique des filaments constitutifs des bâtonnets est visible après l'une et l'autre fixation, mais un réseau quadratique régulier, de 75 Å de côté, n'est clairement apparent qu'après fixation aldéhydique. Le point important est que ce dernier aspect diffère complètement du réseau «oblique» des stries Z normales, et peut être rapproché au contraire du réseau «transversal» de la strie Z obtenu après fixation aldéhydique; l'hypothèse est ainsi soulevée de la constitution des ponts dans les bâtonnets aux dépens d'un seul des deux constituants morphologiques de la strie Z. La topographie des bâtonnets a été également étudiée: tantôt périphérique, au sein de masses sarcoplasmiques latérales, tantôt centrale, au sein de petits foyers de désintégration myofibrillaire. La structure des plaques motrices visibles dans les préparations était normale. La spécificité de la lésion élémentaire et l'autonomie de ce type de myopathie sont ensuite discutées.
    Notes: Summary Ultrastructural study of an observation of “Nemaline Myopathy” has been focused on structural relationships between rods and normal Z-bands in different conditions of fixation. The Z-band structure studied in transversal section, varies with the fixation: network of “oblique” (relative to the regular quadratic pattern of the thin filament endings) bridges after osmic fixation; network of “transversal” bridges, alone or associated to the first network, after aldehydic fixation. The rod structure, in transversal section, is also varying with the fixation: a quadratic disposal of the filamentary content is visible after both fixations, but a regular quadratic network, 75–85 Å side, is clearly appearent only after aldehydic fixation. This last network differs from the “oblique” network of the normal Z-band; it can be compared to the “transversal” one obtained in the Z-band after aldehydic fixation. The hypothesis that bridges in the rods are formed only by one of the two normal morphological components of the Z-band, is raised. Topography of the rods in muscle fibers has been studied: either in peripheral sarcoplasmic masses, or in small central-located foci of myofibrillar disintegration. The end-plates structure was normal. Specificity of the elementary lesion, and autonomy of that type of myopathy is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00690645
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  • 6
    Electronic Resource
    Electronic Resource
    Sodium demonstration in rat cerebrum following perfusion with hydroxyadipaldehyde-antimonate (1969)
    Springer
    Acta neuropathologica 12 (1969), S. 173-182 
    Details
    ISSN: 1432-0533
    Keywords: Sodium Deposits ; Electron Microscopy ; Perfusion with Hydroxyadipaldehyde-Antimonate ; Extracellular Space
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Eine Modifikation der Methode zur ultrastrukturellen Darstellung von Natrium wird beschrieben, die eine Perfusion mit leicht alkalischer Mischung von Hydroxydipaldehyd, Phosphatpuffer und Kalium-Pyro-Antimonat verwendet. Im normalen Gehirn werden keine Natrium-Deposite angetroffen. Das spricht dafür, daß im Gehirn keine intraoder extracelluläre Konzentration über 150 mM vorliegt. Bei Vorliegen hoher NaCl-Konzentration sieht man ein großes, dichtes Präcipitat, das nach direkter Injektion in den extracellulären Räumen, Neuronen und Astrocyten lokalisiert werden kann. Im Mark der vergifteten Ratten findet sich ähnlich wie nach direkter Natrium-Injektion ein diskretes, gleichfalls als Natrium aufgefaßtes Präcipitat an der Oberfläche von Oligodendrogliazellen, aber nicht innerhalb dieser Zellen. Ein elektronendichtes Deposit unklarer Herkunft findet sich in den Myelinspalten, die nach akuter TET-Vergiftung auftreten. Der Wechsel in Charakter und Lokalisation dieser elektronendichten Partikel mahnt zur Vorsicht in ihrer Interpretation bei histochemischen Untersuchungsmethoden.
    Notes: Summary A modification of the technique for the ultrastructural demonstration of sodium is described which involves a perfusion with a slightly alkaline mixture of hydroxyadipaldehyde, phosphate buffer and potassium pyroantimonate. No sodium deposits are found in normal brain indicating that no intra or extracellular concentration exceeding 150 mM is present in the brain. In the presence of high concentration of NaCl, a large dense precipitate can be seen which after a direct injection can be localized to extracellular spaces, neurons and astrocytes. In the white matter of tin poisoned rats, as well as after the direct injection of sodium, a discrete precipitate, also believed to represent sodium, is noted at the surface of oligodendrocytes but not within these cells. An electron dense deposit of dubious origin is present in the myelin clefts which occur as a result of acute triethyltin intoxication. The variations in the character and localization of these electron dense particles emphasize the caution which is required in their interpretation following histochemical procedures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00692504
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  • 7
    Electronic Resource
    Electronic Resource
    Züchtung und Vermehrung von Herpes simplex-Virus in Zellkulturen vom Nervensystem (1969)
    Springer
    Acta neuropathologica 12 (1969), S. 276-299 
    Details
    ISSN: 1432-0533
    Keywords: Herpes simplex Virus ; CNS Tissue Culture ; Multiplication in vitro ; Cytopathic Alterations ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die häufig diskutierte, (Mit)beteiligung von Herpes simplex-Virus (HSV) bei bestimmten Alterationen im ZNS sowie der hohe Neutropismus des HSV führte zur Frage, inwieweit sich HSV auch in in vitro gezüchteten, spezifischen Zellen vom Nerven-system vermehren und züchten läßt, und ob sich hierbei licht-und elektronenmikroskopisch charakteristische Alterationen nachweisen lassen. Es zeigte sich, daß sich das HSV in allen verschiedenen angezüchteten spezifischen Zellen (von Plexus chorioideus des Rhesusaffen, Kaninchenspinalganglien, menschlichen Oligodendrogliomen, Meningeomen sowie fibrillären und protoplasmatischen Astrocytomen) kultivieren und vermehren läßt. Hierbei kommt es in den spezifischen Zellen nicht nur lichtmikroskopisch zu charakteristischen cytopathischen Veränderungen, sondern auch biologisch zu einer signifikanten Vermehrung des Virus in diesen Zellen. Auch elektronenmikroskopisch lassen sich viele der charakteristischen Bildungs-, Reifungs- und Ausschleusungsstadien des Virus in den Kernen und im Cytoplasma der Zellen beobachten. Die Besonderheiten der elektronenmikroskopisch erhobenen ultrastrukturellen Befunde werden ausführlich beschrieben, und die sich daraus abzuleitenden Möglichkeiten werden im Hinblick auf die biologischen Eigenheiten des HSV bei in vivo-Infektionen, aber auch im Hinblick auf die Deutung lichtmikroskopisch histochemischer und immunhistologischer Befunde nach in vivo-Infektionen mit diesem Virus ausführlich diskutiert.
    Notes: Summary The participation of herpes simplex virus (HSV) in certain alterations of the CNS has been partially questioned and frequently discussed. Therefore, the question arose whether HSV can also be cultivated and multiplied in vitro in CNS specific cells, and if so, whether characteristic alterations and structures can be observed by means of light and electron-microscopic examinations. Our data demonstrate that HSV multiplies in all different specific cells originating from plexus chorioideus of rhesus monkeys, from spinal ganglia of rabbit, from human oligodendroglioma, meningeoma as well as from fibrillar and protoplasmatic astrocytoma. Characteristic cytopathic alterations of these specific cells and significant multiplication of the virus in these cells are to be found. Many of the characteristic forms of formation, maturation and release of HSV can be seen by electronmicroscopic examinations. The particular ultrastructural data observed by electron microscopy are described in detail and the resulting possibilities are broadly discussed not only with regard to the biologic particularity of HSV in in vivo infection but also in view of the interpretations, deriving from histochemical and immunohistological data obtained by light microscopy after in vivo infection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687650
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  • 8
    Electronic Resource
    Electronic Resource
    Electron microscopic studies concerning the structural mechanism of the development of mental disturbance in experimental chronic methamphetamine poisoning (1969)
    Springer
    Acta neuropathologica 14 (1969), S. 215-225 
    Details
    ISSN: 1432-0533
    Keywords: Methamphetamine Poisoning (Artificial Psychosis) ; Synapses ; Nerve Conduction and Transmission ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Amphetaminchlorid in Mengen von 1 mg pro kg pro Tag wurde 8 männlichen Meerschweinchen ungefähr 1 Jahr lang täglich injiziert, um eine chronische Amphetaminvergiftung zu erzeugen. Bei jedem vergifteten Tier wurde die Feinstruktur des Gehirns elektronenmikroskopisch untersucht. Die Befunde waren folgende: 1. Verschmelzung der Membranen zwischen Axonen in den Nervenendigungen sowie zwischen Axonen und Dendriten wurden in der Großhirnrinde, im limbischen System, im Thalamus und Hypothalmus beobachtet; ferner wurde eine sich vom Cytoplasma bis zur Nervenendigung erstreckende Membranstruktur in diesen Hirnbereichen festgestellt. 2. Im Frontal-, Parietal-, Temporal- und Occipitalhirn sowie im limbischen System fanden sich vermehrt membranbegrenzte Vesikel im Cytoplasma der Nervenzellen und verdicktes und vermehrtes ER in den Nervenfasern. In Anbetracht klinischer Symptome der Patienten mit Amphetaminvergiftung wurde angenommen, daß die Verschmelzung von Membranen zwischen Nervenfortsätzen und das Auftreten der Membranstrukturen in allen Teilen des Nervenzellcytoplasmas vom Perikaryon bis zur Nervenendigung die wichtigsten Befunde sind, die darauf hindeuten, daß die Vergiftungsvorgänge einen wesentlichen Einfluß auf das Leitungssystem der Nerven ausüben können.
    Notes: Summary In 8 male albino strain guinea pigs, 1 mg/kg of methamphetamine HCl was injected daily for 7 months to 1 year to produce chronic methamphetamine intoxication and to study the fine structure of the brain electron microscopically. The following results were obtained: 1. Coalescence of membranes, between axons at the nerve endings and between axons and dendrites, was found in the cortex of the cerebrum and limbic system, in the thalamus and hypothalamus. Membranous structures were found in all portions of the cytoplasm of the nerve cells. 2. Within the cytoplasm of the nerve cell, coated vesicles were increased in number with hypertrophy and increase of endoplasmic reticulum within nerve fibres in the frontal, parietal, temporal and occipital regions, and in the limbic system. In view of these findings, as well as the clinical neurological symptoms in patients with methamphetamine poisoning, the coalescence of membranes between nerve processes and the appearance of membranous structures in all portions of nerve cell cytoplasm from body to nerve endings appear to represent the most important findings, they probably produce a profound disturbance in the system of nerve conduction and transmission.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00685301
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  • 9
    Electronic Resource
    Electronic Resource
    The inhibition of calcium hydroxyapatite crystal growth by polyphosphonates and polyphosphates (1969)
    Springer
    Calcified tissue international 3 (1969), S. 151-162 
    Details
    ISSN: 1432-0827
    Keywords: Calcification ; Physiologic ; Phosphonic Acids ; Phosphates ; Crystallization ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé On a étudié la formation de l'hydroxyapatite de calcium cristallin à partir de solutions d'ions de calcium et de phosphate et l'inhibition de la croissance de cristaux de l'hydroxyapatite de calcium au moyen de polyphosphonates et de polyphosphates. Les polyphosphonates, éthane hydroxy-1-diphosphonate-1,1 de disodium et dichlorométhanediphosphonate de disodium, sont inhibiteurs efficaces contre la croissance de cristaux de l'hydroxyapatite de calcium. Les polyphosphates sont aussi inhibiteurs efficaces contre la croissance de cristaux de l'hydroxyapatite de calcium tant que le niveau exigé de polyphosphate intact est présent dans le système. Cependant, à cause de leur instabilité hydrolytique, qui est soulignée par une température élevée, valeur de pH basse, et certaines enzymes, la concentration du polyphosphate diminue avec le tempsin vitro, et son activité comme inhibiteur est perdue. Au contraire aux polyphosphates, les polyphosphonates sont hydrolytiquement stables. Les polyphosphonates sont chimiosorbés sur la surface des microcristallites de l'hydroxyapatite de calcium, ainsi empêchant l'occurrence d'autre croissance de cristaux semblable à l'action d'autres poisons connus de croissance de cristaux. On propose l'extension de cette action sur la formation de l'apatite et cette stabilité des polyphosphonates aux applications médicales et dentaires concernant le metabolisme pathologique de calcium et de phosphate.
    Abstract: Zusammenfassung Die Bildung des kristallinen Calciumhydroxyapatit aus Lösungen, welche Calcium- und Phosphationen enthalten, und die Hemmung der Bildung von kristallinen Calciumhydroxyapatit durch Polyphosphonate und Polyphosphate wurden untersucht. Polyphosphonate, Dinatriumäthan-1-hydroxyl-1,1-diphosphonat und Dinatriumdichloromethandiphosphonate verhindern das Kristallwachstum des Calciumhydroxyapatits. Die Polyphosphate verhindern ebenfalls das Kristallwachstum des Calciumhydroxyapatits, solange die notwendige Konzentration des nicht hydrolysierten Polyphosphats vorhanden ist. Wegen ihrer hydrolytischen Unbeständigkeit, die durch hohe Temperatur, niedrige pH und bestimmte Enzyme erhöht wird, vermindert sich jedoch die Konzentration des Polyphosphats allmählichin vitro, und ihre Hemmungsaktivität geht verloren. Im Gegensatz zu den Polyphosphaten sind die Polyphosphonate hydrolytisch beständig. Die Polyphosphonate werden an der Oberfläche der Mikrokristallite des Calciumhydroxyapatits chemisorbiert und verhindern, wie andere bekannte Kristallwachstumsgifte, auf diese Weise weiteres Kristallwachstum. Die Beständigkeit der Polyphosphonate und ihre Chemisorption an dem Apatit empfehlen ihren Gebrauch in der ärztlichen und zahnärztlichen Praxis, soweit sie den pathologischen Calcium- und Phosphatstoffwechsel betreffen.
    Notes: Abstract The formation of crystalline calcium hydroxyapatite from solutions of calcium and phosphate ions and the inhibition of calcium hydroxyapatite crystal growth by polyphosphonates and polyphosphates have been studied. The polyphosphonates, disodium ethane-1-hydroxy-1,1-diphosphonate and disodium dichloromethane diphosphonate, are effective inhibitors of calcium hydroxyapatite crystal growth. The polyphosphates are also effective inhibitors of calcium hydroxyapatite crystal growth as long as the required level of intact polyphosphate is present in the system. However, because of their hydrolytic instability, which is enhanced by high temperature, low pH, and certain enzymes, the concentration of the polyphosphate decreases with timein vitro, and its activity as an inhibitor is lost. In contrast to the polyphosphates, the polyphosphonates are hydrolytically stable. The polyphosphonates are chemisorbed on the surface of the microcrystallites of calcium hydroxyapatite and, in the manner of other known crystal growth poisons, thus prevent further crystal growth. The stability of the polyphosphonates and their chemisorption on apatite suggest their use in medical and dental applications involving pathological calcium and phosphate metabolism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02058658
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  • 10
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    Electronic Resource
    Inhibitory and excitatory factors influencing the receptive fields of lamina 5 spinal cord cells (1969)
    Springer
    Experimental brain research 9 (1969), S. 284-306 
    Details
    ISSN: 1432-1106
    Keywords: Cutaneous receptive fields ; Spinal cord ; Cat ; Pain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Examination of cutaneous receptive fields (RFs) of lamina 5 cells in the lumbar spinal cord of decerebrate cats shows them to have three distinct zones with respect to mechanical and electrical stimulation. The mean response rate to both mechanical and electrical stimulation in zone 1 increases steadily up to the highest strengths used; in zone 2, surrounding zone 1 mainly proximally, mild stimuli reduce the mean rate, stronger stimuli increase it; in zone 3, mainly proximal to zone 2, all stimuli reduce the rate. Temporally, zone 1, electric shocks near threshold produce bursts of firing followed by inhibition. With increased stimulus strength, the bursts lengthen to a second or more. In zones 2 and 3, inhibition at all strengths is preceded at higher strengths by bursts of firing. Cold-blocking the spinal cord at lower thoracic levels reversibly increases the ongoing activity of these cells, increases the area of zones 1 and 2, and almost completely suppresses all inhibition. Stimulation of dorsal columns and threshold stimulation of distant dorsal roots inhibits ongoing and induced activity. Barbiturate decreases ongoing activity and the duration of firing produced by cutaneous electrical stimulation but does not decrease inhibition. These results are consistent with a model in which low-threshold fibres are excitatory only over a small central area of the RF of a lamina 5 cell (zone 1), high threshold fibres are excitatory over a larger area (zones 1 and 2), and low threshold fibres are inhibitory over the entire receptive field (zones 1, 2 and 3) with a slower time-course. This inhibition is tonically enhanced by descending influences in the decerebrate cat. It is suggested that the high and low threshold fibres correspond approximately to the small and large diametre fibres whose balance is the basis for the coding of pain in the theory of melzack and wall.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235240
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  • 11
    Electronic Resource
    Electronic Resource
    The lateral cervical nucleus in the cat IV. A light and electron microscopical study after midbrain lesions with demonstration of indirect wallerian degeneration at the ultra-structural level (1969)
    Springer
    Experimental brain research 7 (1969), S. 51-67 
    Details
    ISSN: 1432-1106
    Keywords: Lateral cervical nucleus ; Midbrain lesions ; Nauta method ; Ultrastructural investigation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The lateral cervical nucleus (LCN) has been studied with the light and electron microscope after midbrain lesions in kittens of different ages, and in adult cats. It has been shown that nerve cells remain within the contralateral LCN after hemisection of the midbrain. performed on 1 day old kittens. The estimated number of these remaining cells was 3–19% in the different cases. No fibers descending to the LCN from levels rostral to the midbrain could be demonstrated in adult cats with the Nauta technique. A combined Nauta and electron microscopical investigation was performed on kittens operated on at different ages and allowed to survive varying times postoperatively. At the operations the LCN-axons were transected at midbrain level. The Nauta investigation demonstrated silver impregnation of degenerating LCN-neurons on the affected side of the same type as has been described recently in other neuronal systems following axonal transection. The ultrastructural study revealed electron dense degenerating dendrites and probably also nerve cells within the LCN. The dense degenerative changes were very similar to the dense degeneration in terminal boutons following transection of parent axons. The potential value of the findings for electron microscopical research in neuroanatomy is discussed. The results in terms of connections of the LCN are discussed in the light of known anatomical and physiological data of the LCN.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236107
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  • 12
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    Electronic Resource
    Contrôle de l'activité des fibres fusimotrices dynamiques et statiques par la formation réticulée mésencéphalique chez le chat (1969)
    Springer
    Experimental brain research 9 (1969), S. 307-324 
    Details
    ISSN: 1432-1106
    Keywords: Muscle spindle ; Gamma motor control ; Mesencephalic reticular formation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Effects of repetitive stimulation of the mesencephalic reticular formation (MRF) on the static discharge and dynamic sensitivity of muscle spindle primary endings (soleus muscle) were studied in cats anaesthetized with Halothane (Fluothane). By progressive increasing the depth of anaesthesia three different fusimotor effects could be observed: 1. A static effect; the static discharge of the primary endings was strongly increased; the response to phasic stretch was decreased or remained unaltered. 2. A dynamic effect; the dynamic sensitivity of the primary endings was powerfully increased while the rate of discharge under static conditions was only slightly augmented. 3. A depressant effect; the static discharge and the dynamic sensitivity of primary endings were decreased. Repeated stimulation elicited successive static and dynamic effects. No specific regions within the MRF could be related to a particular effect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235241
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  • 13
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    Electronic Resource
    Etude fonctionnelle du contrôle de l'activité des fibres fusimotrices dynamiques et statiques par les formations réticulées mésencéphalique, pontique et bulbaire chez le chat (1969)
    Springer
    Experimental brain research 9 (1969), S. 325-345 
    Details
    ISSN: 1432-1106
    Keywords: Muscle spindle ; Gamma motor control ; Reticular formations ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. During a progressive increase of Fluothane (Halothane) anaesthesia, repetitive stimulation of the mesencephalic retioular formation (MRF) produces several fusimotor effects — static, dynamic or depressant — on primary endings of soleus muscle spindles (Vedel et Mouillac-Baudevin 1969). 2. Transection of the brain immediately rostral to the site of stimulation may increase the dynamic effect but does not alter the static or the depressant effects. 3. A section of the rubrospinal tract does not modify the fusimotor effects elicited by stimulation of the MRF. 4. Transections of the spinal cord have shown that the pathways responsible for the transmission of these effects are mainly situated in the ipsilateral ventral and ventrolateral funiculi which contain the efferent fibers from the pontine reticular formation (PRF), from the bulbar reticular formation (BRF) and from the vestibular nucleus. 5. Contra and ipsilateral PRF stimulation produces the static fusimotor effect; contralateral stimulation from a small anterior region produces the dynamic effect. 6. Stimulation of the lateral part of the ipsilateral BRF elicits the dynamic effect while stimulation of the medial part elicits the static effect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235242
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  • 14
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    Electronic Resource
    The lateral cervical nucleus in the cat III. An electron microscopical study after transection of spinal afferents (1969)
    Springer
    Experimental brain research 7 (1969), S. 32-50 
    Details
    ISSN: 1432-1106
    Keywords: Lateral cervical nucleus ; Spinal lesions ; Ultrastructural investigation ; Degenerating boutons ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of terminal degeneration within the lateral cervical nucleus (LCN) after transection of its spinal afferent fibers 2 days–2 years earlier is described. The degeneration after 2 days was of both the neurofilamentous and dense type. The highest number of degenerating terminals, about 15%, was found after 4–5 days. Then most of the degenerating boutons were of the dense type. The degenerating terminals had synaptic contact with cell bodies and dendrites of LCN-neurons. Removal of the degenerating boutons seemed to be effected by a phagocytic cell present in increased number compared to the normal LCN. In cases with long survival times an increase in the number of astroglial filaments was observed. In an animal where the spinal afferents to the LCN had been cut 2 years earlier a decrease in medium size of the neurons was observed. The amount of dendritic spines was also considerably smaller than normally.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236106
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  • 15
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    Electronic Resource
    Inhibition in the medial geniculate body of the cat (1969)
    Springer
    Experimental brain research 7 (1969), S. 68-83 
    Details
    ISSN: 1432-1106
    Keywords: Medial geniculate body ; Inhibition ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Inhibitory activity in the cat medial geniculate body (MG) was examined by stimulating electrically and acoustically the input and output of the MG. 2. A longer and more profound depression of excitability occurs following a click-evoked potential in the MG than in the inferior colliculus (IC) in both anesthetized and unanesthetized states. Recovery is cyclic in the barbiturate MG preparation. 3. Electrical stimulation of the brachium of the inferior colliculus (BIG) evokes a field potential in the MG consisting of clearly distinguishable presynaptic and postsynaptic components. The presynaptic component recovers rapidly, while the postsynaptic component requires 100–200 msec for full recovery. This depression of excitability is localized within the MG since cortical ablation does not alter its occurrence. 4. Stimulation of the BIC mimics the effects of click stimulation on single units. Excitatory, inhibitory and reverberatory responses are evoked by the BIC shock. Suppression of single unit activity correlates with the depression of excitability following a BIC-evoked field response. 5. Cortical stimulation can evoke antidromic and trans-synaptic unit responses in the MG, as well as causing a variety of inhibitory effects and reverberation. In view of the fact that cortical ablation does not impair the recording of these responses to afferent stimuli, it is suggested that the cortical-evoked responses are at least partly mediated by antidromic conduction to MG. 6. Evidence is presented that inhibitory effects of both afferent and cortical stimulation are due to active inhibition of MG unit activity. Speculations are made as to the mechanisms producing inhibition and reverberation in the MG.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236108
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  • 16
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    Electronic Resource
    Electronmicroscopic observations on the structure of the pontine nuclei and the mode of termination of the corticopontine fibres an experimental study in the cat (1969)
    Springer
    Experimental brain research 7 (1969), S. 95-110 
    Details
    ISSN: 1432-1106
    Keywords: Electron microscopy ; Pontine nuclei ; Experimental neuroanatomy ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The electron microscopical changes occurring in the pontine nuclei following unilateral lesions of the primary sensorimotor cortex have been studied in 7 cats with a survival time from 2–23 days. A description is also given of the fine structure of the pontine regions in receipt of the fibres. These regions are shown in Fig. 1. The study shows that the boutons are practically only in synaptic contact with dendrites. The bouton density on these is only 16%. The boutons are of the en passage and terminal type, with the latter as the most common (Figs. 4a-e). The synaptic vesicles are rounded or elongated. The formaldehyde fixed material had 17.8% boutons with vesicles of the elongated type; the material fixed with a mixture of formaldehyde and glutaraldehyde had only 11.5% of such boutons. The degenerating boutons show the dark type of reaction and the majority of the corticopontine fibres are of the type shown in Figs. 4d and 4e. Astrocytes and microglial cells participate in the removal of degenerating boutons and terminal fibres. Degenerating boutons are present even at the 23 day stage and some have apparently only started to degenerate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235436
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  • 17
    Electronic Resource
    Electronic Resource
    Die Bedeutung der Vorderhirnkommissuren für die Koordination bilateraler EEG-Muster (1969)
    Springer
    Experimental brain research 7 (1969), S. 195-213 
    Details
    ISSN: 1432-1106
    Keywords: Corpus callosum ; EEG synchronization ; Homolateral sensory evoked potentials ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Spontaneous EEG-patterns and evoked potentials (EP's) of symmetrical cortical areas were recorded in chronic and acute cats before and after section of the corpus callosum, the commissura anterior and posterior and the massa intermedia. The spontaneous EEG was recorded without and with anesthesia, EP's after electrical stimulation of the fore-paws only during nembutal anesthesia. — No changes in the bilateral coordination of spontaneous and evoked EEG-patterns could be seen after commissurotomy (CT). The bilateral coherence of EEG-waves as revealed by cross-correlation is low already in the normal cats and does not change significantly after CT. The values of cross-correlation coefficients at T = ± 15 msec vary during one EEG-record between -0.25 and +0.25 in the somatosensory, suprasylvian and temporal areas (mean values slightly above 0). In the visual area occasionally positive values between 0.5 and 0.8 were seen, but also here a large variation was found in all animals and the mean values were below 0.1. No consistent phase shift between both sides was observed. EEG-patterns like spindles or arousal, still occurred together in both hemispheres after CT, the variability of their exact beginning or end was the same as in controls. Spontaneous spindles often lasted longer after section of the massa intermedia. Homolateral EP's in the somato-sensory area were still present after CT. Rhythmical afterdischarges could be restricted to the contralateral somato-sensory cortex even before CT.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239029
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  • 18
    Electronic Resource
    Electronic Resource
    Evidence for mediated transport of chloride in cat cerebral cortex in vitro (1969)
    Springer
    Experimental brain research 8 (1969), S. 219-231 
    Details
    ISSN: 1432-1106
    Keywords: Cerebral cortex in vitro ; Chloride transport ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The kinetics of the uptake of chloride by slices of cat cerebral cortex incubated in vitro have been studied for a wide range of concentrations of chloride and potassium in the incubation media. 1. In studies with 36Cl at a constant concentration of external K+, the rate of entry of chloride into slices of cat cerebral cortex (after equilibration with the fluid of the extracellular space) followed Michaelis-Menten kinetics with Vmax=7.7 μmoles/g/min and Km=245 mM. The kinetic data so described differ significantly from a curve describing simple diffusion (P 〈 0.02). 2. A clear dependence on concentration of K+ in the incubation medium was demonstrated. When external chloride was held constant at 6.8 mM and concentrations of potassium were varied over a range of 27–100 mM, the apparent rate of entry of chloride followed Michaelis-Menten kinetics with Vmax=0.191 μmoles/ g/min and Km=30.3 mM. 3. Under similar equilibrium conditions, the rate of influx of chloride was not statistically different from the rate of efflux, and the value for extracellular space (355 μl/g) derived by extrapolation from efflux data was of an identical order of magnitude to the value (352 μl/g) obtained from influx data. These values are essentially identical to those previously determined for chloride space of cat cerebral cortex in vivo (Bourke, Greenberg and Tower 1965). 4. The total, membrane-delimited content of chloride in cerebral cortex, as defined in these studies in vitro, was a function of the concentration of K+ in the incubation medium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234250
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  • 19
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    Electronic Resource
    Studies of the development and subsequent reduction of swelling of mammalian cerebral cortex under isosmotic conditions in vitro (1969)
    Springer
    Experimental brain research 8 (1969), S. 232-248 
    Details
    ISSN: 1432-1106
    Keywords: Cerebral cortex in vitro ; Edema ; Fluid compartmentation ; Chloride transport ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ionic parameters of incubation media which foster both the development and subsequent reduction of swelling of slices of cerebral cortex under isosmotic conditions of incubation in vitro are described. A linear relationship between increasing chloride concentrations in incubation media and progressive swelling of tissue slices (under conditions of constant temperature and K+ concentrations and isotonicity of incubation media) is demonstrated. Subsequent reduction of chloride concentration in incubation media together with reciprocal replacement by isethionate is associated with significant and characteristic reduction in the volume of tissue swelling when all other conditions of incubation, including isotonicity of the media, are kept constant. The ionic composition of the fluid of swelling under different conditions of incubation is derived together with the ionic composition and expected transmembrane potentials of the neuronal compartment of cerebral cortex in vitro. Mechanisms involved in the development and subsequent reduction of swelling of cerebral cortex in vitro are discussed, and proposals for possible clinical applications are suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234251
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  • 20
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    Electronic Resource
    Integration konvergierender Afferenzen in der bulbären Formatio Reticularis der Katze (1969)
    Springer
    Experimental brain research 7 (1969), S. 143-157 
    Details
    ISSN: 1432-1106
    Keywords: Reticular formation ; Convergence ; Inhibition ; Cat ; Chloralose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 1. Ein konditionierender corticaler Reiz inhibiert den somatischen Startlereflex bei Katzen unter Chloralosenarkose für eine Dauer von mehr als 200 ms. Die Interaktionen zwischen beiden Reizen laufen in der bulbären und pontinen Formatio reticularis ab. 2. Dem Startlereflex liegt eine polysynaptische Erregungsschleife zugrunde, die die bulbäre und pontine Formatio reticularis durchzieht. Die Resistenz der reticulären Neurone gegenüber repetitiver Stimulation wurde als Kriterium ihrer funktionellen Lokalisation auf dem polysynaptischen Reflexbogen gewertet. 3. Die corticale Inhibition wird im Verlaufe der polysynaptischen Erregungsschleife zunehmend stärker. Neurone, die von den Startlereflexafferenzen direkt erregt werden, werden durch den corticalen Reiz nicht inhibiert. Dies schliebt eine präsynaptische Inhibition der reticulopetalen Fasersysteme aus.
    Notes: Summary 1. The startle reflex evoked by cutaneous stimulation in cats under chloralose anesthesia is inhibited for more than 200 ms by a conditioning cortical volley. The interaction between the cutaneous and the cortical volley takes place in the bulbar and pontine reticular formation. 2. The startle reflex involves a series of reticular neurones. Resistance to repetitive stimulation has been determined to evaluate the functional localization of each neurone within this polysynaptic path. 3. Inhibition following the cortical volley becomes increasingly more effective along the course of the polysynaptic path and is completed within 5–6 ms. Reticular neurones excited directly by the spino-reticular afferents are not inhibited, thus excluding a presynaptic inhibition of the spinoreticular fibres.
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    URL: http://dx.doi.org/10.1007/BF00235440
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  • 21
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    Electronic Resource
    Functional organization of the vestibular afferents to the cerebellar cortex of frog and cat (1969)
    Springer
    Experimental brain research 9 (1969), S. 30-52 
    Details
    ISSN: 1432-1106
    Keywords: Climbing fibers ; Mossy fibers ; Vestibulo-cerebellar input ; Cat ; Frog ; Golgi cell inhibition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Field and unitary potentials evoked in the vestibulo-cerebellum of frog and cat following vestibular nerve stimulation were recorded with microelectrodes and correlated with their site of origin in the various layers of the cerebellar cortex. 2. In the frog, primary vestibular fibers project both as mossy and as climbing fibers onto the cerebellar auricular lobe. Secondary vestibulo-cerebellar fibers seem to end exclusively as mossy fibers in the auriculum. As a consequence of this dual projection, extra- and intracellular recordings from Purkinje cells in the auricular lobe show two kinds of responses to vestibular nerve stimulation: a) graded, repetitive firing mediated through mossy fiber-granule cell-parallel fiber pathways, and b) all-or-none burst responses caused by monosynaptic impingement of vestibular climbing fibers on Purkinje cells. 3. The field and unitary potentials evoked in the cat nodulus, flocculus and uvula following vestibular nerve stimulation are shown to be generated by mossy fibers exclusively. Considerable convergence of the two labyrinthine mossy fiber inputs to a given cerebellar area was found. 4. Interaction of contralateral and ipsilateral mossy fiber input at the level of the flocculus suggests that Golgi cell inhibition might operate not only as a simple inhibitory feedback loop, but also as a complex gating operator at the granule layer. 5. No short latency climbing fiber activation of Purkinje cells was observed following VIIIth nerve stimulation. Stimulation of the contralateral inferior olive evoked short latency climbing fiber EPSPs in Purkinje cells of the vestibulo-cerebellum. Suggestions are made as to the possible role of mossy and climbing fiber inputs to this area of the cerebellum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235450
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  • 22
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    Electronic Resource
    Pyramidal control of fusimotor neurons supplying extensor muscles in the cat's forelimb (1969)
    Springer
    Experimental brain research 9 (1969), S. 96-115 
    Details
    ISSN: 1432-1106
    Keywords: Pyramidal tract ; Fusimotor Neurons ; Forelimb ; Extensor ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of cortical stimulation upon dynamic and static sensitivities of the sensory endings in muscle spindles have been analyzed. 63 single afferent fibers from the muscle spindles of the forelimb extensors: M. flexor carpi radialis, M. flexor digitorum communis and M. palmaris longus were isolated in dorsal root filaments in 20 adult cats under chloralose-urethane anesthesia. They were identified by their response to stimulation of the median nerve. 1. Surface anodal repetitive stimulation of the anterior sigmoid gyrus was found to produce an enhancement of static response of single Group II fibers. Effective area was localized in a restricted region which corresponded to the forelimb motor area. The effect was obtained without any concomitant muscle contraction. Similarly, the stimulation increased the resting discharges of the Group Ia fibers from the same muscles. 2. Stimulation of the same area in the cerebral cortex was also found to increase the dynamic sensitivities of primary sensory endings. The increase was revealed by an enhancement of initial burst discharge during relaxation period of a twitch contraction caused by median nerve stimulation. 3. These results indicate that stimulation of the forelimb motor area has a facilitatory effect on both the static and dynamic fusimotor neurons innervating the muscle spindles of the test muscles. 4. The effects were reproduced in pyramidal tract preparations in which the brainstem was cut either at the level of the midbrain except for the cerebral peduncle or at the level of caudal medulla oblongata sparing the pyramid. 5. The threshold for the fusimotor effects was less than 1.3–1.5 times threshold of the pyramidal tract discharge, when the best spot for eliciting the fusimotor response was chosen. These results indicate that the effects of cortical stimulation are mainly mediated by the fast conducting pyramidal tract fibers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238324
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  • 23
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    Electronic Resource
    Die asynchrone und lokal umschriebene Reizwirkung von Mittelfrequenz-Dauerströmen im Hypothalamus der Katze (1969)
    Springer
    Experimental brain research 9 (1969), S. 164-182 
    Details
    ISSN: 1432-1106
    Keywords: Emotional behaviour ; Hypothalamus ; Electricalstimulation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. In order to compare the selective value of repetitive cathodal pulses of 8 c.p.s. and of continuous sine-wave alternating currents of 5000 c.p.s. (middle frequency current) when applied to brain tissue, explorations were made in the region of the hypothalamus that had yielded defence and/or flight reactions in earlier experiments. The region was explored by stimulating each point in turn with both current forms. At the same time measurement was made of the impedance of the brain tissue, and the effects produced by altering the time of rise of the middle frequency current on threshold of responses were also studied. The experiments were carried out on unanaesthetized, freely moving cats. 2. Both stimulation types produced affective (“emotional”) responses. The patterns elicited by low frequency cathodal pulse stimulation were often associated with stimulus-bound phasic muscle activity, i.e., flapping of ears, and twitching of whiskers, or, rotation of the head. Such extraneous motor effects were rarely obtained when continuous middle frequency currents were applied, and were tonic in character when present. 3. Mapping of reactive points revealed that the area producing defence or flight following middle frequency stimulation is smaller in size than the field delimited by means of repetitive cathodal pulse stimulation. These results strongly suggest that spread of current can be reduced by using middle frequency current stimulation. This apparently local (and hence highly selective) action is paralleled by a lower impedance of the brain tissue to the rapidly changing polarity of this current. 4. The hissing (and/or growling) associated with the defence pattern showed adaptation to suddenly rising middle frequency currents of 30 secs duration. An increase in threshold of hissing occurred when the time of rise of the current was prolonged. Flight, in contrast, was obtained at the same critical intensity regardless of the time of rise of current. 5. The nature of the stimulatory action of middle frequency current (examined in the peripheral nerve by Wyss) and the advantages presented by this new method of brain stimulation are briefly discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238329
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  • 24
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    Electronic Resource
    Defence, attack, and flight elicited by electrical stimulation of the hypothalamus of the cat (1969)
    Springer
    Experimental brain research 8 (1969), S. 113-129 
    Details
    ISSN: 1432-1106
    Keywords: Emotional behaviour ; Hypothalamus ; Electrical stimulation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Affective behaviour patterns produced by electrical stimulation of the hypothalamus were studied in unanaesthetized, freely-moving cats. Bipolar stimulation with coaxial electrodes and small cathode was used to elicit defence, attack or flight. The development of these responses was studied by varying stimulation strength. In some experiments a stuffed animal was introduced in order to study the reactions of the cat to changes in the environment during stimulation. 2. The following responses were evoked at threshold intensity: (i) growling reaction; (ii) hissing reaction; (iii) two types of flight — type a preceded by hastily looking to and fro as if in search of an exit, type b preceded by inspection of surroundings, in most cases associated with sniffing. 3. Increasing stimulation 1.5 times threshold often yielded combined patterns. At points yielding the growling reaction a defence response in which growls alternated with hisses was obtained. The points yielding flight type a sometimes yielded hissing followed by flight. Increasing stimulation at hissing points yielded either a defence reaction or the combined effect hissing-flight. 4. The growling reactions were obtained from the tuber region. The hissing responses were obtained from points above the tuber. The flight reactions, type a, were produced from the intermediate zone extending from the level of the preoptic area to the mamillary bodies and type b from the caudo-lateral hypothalamus. 5. The reactions of the cats to a dummy during stimulation varied depending on the type of response which had been evoked in the absence of the dummy. The defence reaction was converted into threatening and striking of the dummy, the combined effects into threatening, striking or biting, culminating in sudden flight. The dummy was ignored during stimulation of points yielding flight type a, but examined by sniffing during stimulation of points yielding flight type b.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234534
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  • 25
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    Electronic Resource
    Interaction of defence and flight reactions produced by simultaneous stimulation at two points in the hypothalamus of the cat (1969)
    Springer
    Experimental brain research 8 (1969), S. 130-149 
    Details
    ISSN: 1432-1106
    Keywords: Emotional Behaviour ; Hypothalamus ; Electrical stimulation ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. The results presented in the present paper are an extension of preceding work devoted to exploration of the hypothalamic defence and flight fields using coaxial electrodes with small cathode. In 33 cats simultaneous stimulation was applied to two points which upon single stimulation had yielded defence, flight, or defence and flight respectively. Results were compared with those produced at either point alone. In 2 cats combined stimulation of a defence and a flight point was carried out with a stuffed cat present. 2. The latencies and rates of the vocal effects associated with defence (growling and hissing), and the latencies of flight (jump from the table) were measured. 3. Simultaneous stimulation of two points which had yielded defence, or of two points which had yielded flight resulted in facilitation (spatial summation) of the effects evoked: a more complete defence response associated with decrease of the latencies and increase in the rates of the vocal effects; decrease of flight latencies and increase of flight impetuosity. 4. Simultaneous stimulation of a defence point which had yielded growling at lower threshold than hissing, and of a point which had yielded flight resulted in facilitation of hissing. Growling and flight were often suppressed; when they occurred, latencies were lengthened and growling rates were increased somewhat. 5. Stimulation of a defence point with a dummy present produces striking (fending off). Simultaneous stimulation of a flight point resulted in facilitation of both hissing and striking. 6. It is concluded that the complex patterns obtained when defence is combined with flight are the result of facilitatory and inhibitory interaction between the elements of the individual patterns.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234535
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  • 26
    Electronic Resource
    Electronic Resource
    Eine faktorenanalyse von schwellen subcorticaler reizantworten (1969)
    Springer
    Experimental brain research 8 (1969), S. 79-96 
    Details
    ISSN: 1432-1106
    Keywords: Evoked potential thresholds ; Factor analysis ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Zur Beschreibung von Korrelationen zwischen zahlreichen elektrophysiologischen Daten aus verschiedenen Hirngebieten wurde eine Faktorenanalyse nach der Hauptachsenmethode gerechnet. Ausgangsmaterial dieser Analyse waren Schwellen subcortical ausgelöster und abgeleiteter Antwortpotentiale auf Einzelreize. Das resultierende Faktorenmuster ermöglicht ein quantitatives Konzept der Schwellendetermination subcorticaler Reizantworten und zugleich ein Modell von Funktionsbeziehungen zwischen einigen Hirnstrukturen. Die Reizungen und Ableitungen erfolgten bei 35 encéphale isolé-Katzen mit Hilfe bipolarer Elektroden in folgenden Arealen: Amygdala, Hippocampus, Septum, N. dorsomedialis Thalami, Hypothalamus posterior und Formatio reticularis mesencephali. Es wurden 435 Korrelationskoeffizienten zwischen den Schwellen von 30 subcorticalen Verbindungen gebildet und zum Zwecke einer Datenreduktion durch eine Matrix von 5 Faktoren reproduziert. 1. Jeder Faktor repräsentierte hohe Schwellenkorrelationen zwischen den efferenten Projektionen jeweils eines Kerngebietes. Demnach nimmt im allgemeinen die Aktivität des Reizortes den größten Einfluß auf die Schwelle eines Antwortpotentials. Diese Hypothese ist durch pharmakologische Untersuchungen belegt worden [27] 2. Kovariationen von Reizantworten mit identischen Ableiteorten ergaben sich ausnahmslos, wenn die Latenzzeiten mehr als 11 msec betrugen. 3. Zusätzlich zeigte die Faktorenmatrix Schwellenkorrelationen zwischen: a) den hypothalamischen Efferenzen und mehreren hippokampalen Afferenzen langer Latenz (positive Korrelationen) b) retikulo-limbischen Verbindungen und „primären” Efferenzen von Amygdala und Hippocampus (positive Korrelationen) c) Antwortpotentialen, die durch Reizung der Formatio reticularis, und solchen, die durch Reizung des N. Amygdalae ausgelöst waren (negative Korrelationen) d) den Efferenzen des N. dorsomedialis Thalami und limbischen Projektionen langer Latenz zur mesencephalen Formatio reticularis (positive Korrelationen) Die Interpretation dieser Zusammenhänge bestätigt und erweitert einige bekannte Modelle von Beziehungen zwischen subcorticalen Kerngebieten. Abschließend wird mit Rücksicht auf die Linearität der mathematischen Methode die Anwendbarkeit der Faktorenanalyse auf Schwellen von Reizantworten diskutiert.
    Notes: Summary In 35 cats (encéphale isolé) evoked responses were elicited and recorded with bipolar electrodes from the amygdala, hippocampus, septum, dorsomedial thalamic nucleus, posterior hypothalamus, and mesencephalic reticular formation. Correlations between the thresholds of responses in different areas following stimulation of other areas were described by a factor analysis according to the principal axis method. 435 coefficients of correlation were calculated and reproduced by a matrix of 5 factors for the purpose of data reduction. Each factor represented high threshold correlations between the efferent projections of one region, which suggests that the activity of the stimulated site exerts a major influence on the evoked potential threshold. This is supported by pharmacological studies [27, 49]. Covariations of responses recorded in the same nucleus were always found, if the latencies exceeded 11 msec. The factor matrix indicated threshold correlations between: the efferent projections of the hypothalamus and several long latency afferent projections to the hippocampus (positive correlations); reticulo-limbic connections and “primary” efferent connections of the amygdala and hippocampus (positive correlations); evoked potentials following reticular and amygdaloid stimulation (negative correlations); the efferent projections of the dorsomedial thalamic nucleus and long latency limbic projections to the mesencephalic reticular formation (positive correlations). The interpretation of these relationships confirms and extends some well known models of relations between subcortical regions. The applicability of factor analysis to evoked potential thresholds is discussed with regard to the linearity of the mathematical method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234927
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  • 27
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    Electronic Resource
    Bildung von markscheidenähnlichen Spiralstrukturen durch lamelläre Astrocytenausläufer innerhalb subpialer und perivasculärer Gliosen des Säugetiergehirns (1969)
    Springer
    Acta neuropathologica 12 (1969), S. 98-102 
    Details
    ISSN: 1432-0533
    Keywords: Marginal Siderosis ; Electron Microscopy ; Myelin-Sheath-Like Structures ; Plaques Fibromyéliniques ; Gliosis, Perivascular, Subpial
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Bei Kaninchen mit einer experimentell erzeugten Randzonensiderose des Zentralnervensystems konnten elektronenmikroskopisch in der Großhirnrinde eigentümliche Spiralstrukturen beobachtet werden. Diese Spiralen fanden sich vornehmlich im Bereich von subpialen und perivasculären Gliosen vor. Sie bestanden aus äußerst dünnen lamellären Astrocytenausläufern, welche um andere astrocytäre Zellfortsätze oder um Dendriten aufgewickelt waren. Die spiralisierten Astrocytenausläufer wiesen in ihrem Inneren feine Filamente mit einer ziemlich regelmäßigen Anordnung auf. In radiärer Richtung ließen die astrocytären Lamellenspiralen eine periodische Schichtung erkennen, welche etwas an die von echten Markscheiden erinnerte. Es wird in Betracht gezogen, daß sie das submikroskopische Äquivalent der sog. Plaques fibromyéliniques darstellen.
    Notes: Summary Peculiar spiral structures could be observed by electron microscopy in the cerebral cortex of rabbits with an experimentally produced marginal siderosis of the central nervous system. These spirals were found predominantly within areas of subpial and perivascular gliosis. They consisted of extremely thin lamellar astrocyte extensions winding around other astroglial processes or dendrites. The spirally coiled astrocyte extensions exhibited within their interior fine filaments having a rather regular arrangement. In the radial direction, the astrocytic lamellae spirals showed a periodic stratification somewhat resembling that of true myelin-sheaths. They were considered to represent the submicroscopic equivalent of the socalled plaques fibromyéliniques.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00685315
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  • 28
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    Electronic Resource
    Structural changes of the central nervous system in swayback (enzootic Ataxia) of lambs (1969)
    Springer
    Acta neuropathologica 12 (1969), S. 307-313 
    Details
    ISSN: 1432-0533
    Keywords: Swayback of Lambs ; Electron Microscopy ; Corpus Callosum ; Myelogenesis ; Axonal Changes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Elektronenmikroskopische Untersuchung des Corpus callosum normaler Lämmer und von solchen mit „Swayback” (enzootische Ataxia) ergab den morphologischen Nachweis normaler Myelinentwicklung in beiden Tiergruppen. Von zwei Zellfortsätzen umgebene Axone wurden häufig beobachtet. Reaktive Veränderungen wurden in Axonen der „Swayback”-Lämmer gefunden. Die Bedeutung dieser Befunde wird besprochen.
    Notes: Summary An electron microscopic study of the corpus callosum of normal and swayback lambs has revealed morphological evidence of normal myelinogenesis in both groups of animals. Axons wrapped by two cell processes were frequently encountered. Reactive changes were found in axons in the swayback lambs. The significance of these findings is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00809127
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  • 29
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    Electronic Resource
    Intranucleäre stabförmige Gebilde bei einem Oligodendrogliom (1969)
    Springer
    Acta neuropathologica 13 (1969), S. 289-293 
    Details
    ISSN: 1432-0533
    Keywords: Oligodendroglioma ; Nuclear Inclusions ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wird die Ultrastruktur von intranucleären stabförmigen Gebilden bei einem Oligodendrogliom beschrieben.
    Notes: Summary Ultrastructure of intranuclear rodlets in an oligodendroglioma is described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00690649
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  • 30
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    Electronic Resource
    Electron microscopic studies on the cerebral lesions of rats in experimental carbon monoxide poisoning (1969)
    Springer
    Acta neuropathologica 14 (1969), S. 118-125 
    Details
    ISSN: 1432-0533
    Keywords: Carbon Monoxide Poisoning ; Electron Microscopy ; Myelin Disintegration ; Cerebral Anoxia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Nach experimenteller CO-Vergiftung fanden sich schwerere und ausgedehntere Läsionen in der weißen als in der grauen Hirnsubstanz. Zwischen akuter und chronischer CO-Vergiftung ergaben sich keine wesentlichen qualitativen Unterschiede der Hirnveränderungen. Die Läsionen nach chronischer Intoxikation waren jedoch schwerer als nach akuter Vergiftung. Die Nervenzellen zeigten leicht dilatiertes oder fragmentiertes EPR und Golgi-Komplexe, doch boten die Mitochondrien meist keine pathologischen Veränderungen. Bei chronischen Fällen fand sich gelegentlich eine deutliche Schwellung des EPR von Oligodendrogliazellen. Die Capillaren blieben intakt und die perivasalen Astrogliaendfüßchen waren nicht geschwollen. Im Mark kam es zu teilweisem Ausfall der normalen Markscheidenbestandteile. Die Marklamellen zeigten mäßige Exfoliation sowie eine Umwandlung in homogene oder strukturlose Substanz. Bemarkte Axone waren teilweise kontrahiert und zeigten auf Querschnitten unregelmäßige Form. Gelegentlich fand sich eine Vergrößerung der axonalen Mitochondrien und Zerstörung ihrer inneren Parallelstrukturen. Als Hauptfaktoren in der Pathogenese der Hirnveränderungen nach experimenteller CO_Vergiftung werden zerebrale Anoxie infolge CO-Hämoglobinbildung, cytotoxische Wirkung von CO auf das Hirngewebe und eine Störung der Blutzirkulation angenommen.
    Notes: Summary In experimental carbon monoxide poisoning, more marked and widespread pathological changes in the brain were seen in the white matter as compared with the gray matter. No essential difference, in the appearance of cerebral alterations, was detected between acute and chronic carbon monoxide poisoning. It was confirmed that the changes resulting from chronic poisoning showed a higher degree of severity as compared with those resulting from acute poisoning. Nerve cells with slightly dilated or fragmented endoplasmic reticulum and Golgi complex in the gray matter were found infrequently. However, most mitochondria did not show any kind of abnormality in such cells. A remarkable dilatation of the endoplasmic reticulum of oligodendrocytes was sometimes seen in chronic cases. Capillaries remained intact and astrocytic perivascular foot-plates were not swollen. In the white matter, the normal constituents of the myelin sheath were partially lost and the myelin lamellae showed moderate exfoliation, or a change into homogenous or structureless substance. Myelinated axons were partially contracted and showed an irregularity in shape in transverse sections. Enlargement of occasional axonal mitochondria and the destruction of their internal parallel structures were observed. Cerebral anoxia caused by carboxyhaemoglobin, together with the cytotoxic action of carbon monoxide on the brain tissue and the disturbance of blood circulation in the brain are suggested as the chief factors in the pathogenesis of the cerebral alterations induced by experimental carbon monoxide poisoning.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00686348
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    Electron microscopic alterations in the vicinity of epileptogenic cobalt-gelatine necrosis in the cerebral cortex of the rat (1969)
    Springer
    Acta neuropathologica 14 (1969), S. 201-214 
    Details
    ISSN: 1432-0533
    Keywords: Electron Microscopy ; Epilepsy, Experimental ; Focus ; Cobalt Gelatine ; Plasmatic Infiltration ; Brain Edema
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Bei 25 erwachsenen Ratten wurde ein epileptogener Kobaltgelatineherd in einer Standardregion der Hirnrinde erzeugt. Die Tiere wurden am 1., 3., 5., 8., 14. 21. und 28. Tag nach der Operation getötet. Das Gebiet des epileptogenen Herdes wurde elektronenmikroskopisch untersucht. Die frühesten Veränderungen bestanden in ödem. Später traten Veränderungen der Astrocytenfortsätze auf, die sich an die Basalmembranen der Capillaren anlegten; die Intercellularräume erweiterten sich, füllten sich mit elektronenoptisch dichten Massen und entwickelten ein “plasmatisches Infiltrat”. Allmählich breitete sich dieses Exsudat weiter um die Capillaren aus; es trat an Orten auf, wo die Astrocytenfortsätze und die Dendriten schwer geschädigt waren und erfüllte die weiteren Intercellularräume des Neuropils. Die Nervenzellen zeigten eine auffallende Widerstandsfähigkeit gegenüber diesem pathologischen Prozeß. Manchmal waren sie umschlossen von Exsudatmassen und zum Teil oder ganz der zarten neuralen und Astrocytenfortsätze beraubt, von denen sie normalerweise umgeben sind. Unsere Befunde werden als das ultrastrukturelle Korrelat der Schols'schen “plasmatischen Infiltration” interpretiert.
    Notes: Summary In 25 adult rats an epileptogenic cobalt-gelatine focus was produced in a standard region of the cerebral cortex. The animals were killed successively on the 1st, 3rd, 5th, 8th, 14th, 21st and 28th day after operation and the region of the epileptogenic focus was examined electron microscopically. The earliest changes were those of oedema. Later there occurred disturbances of the astrocytic processes which cling to the basement membranes of the capillaries; the intercellular spaces widened and filled with rather E. M. dense masses and a “plasmatic infiltrate” developed. Gradually this exudative substance spread even further from the capillaries. It appeared in places where the astrocytic processes were severely demaged and the dendrites were partly dissipated and it filled out the wide intercellular spaces of the neuropil. The nerve cells showed a striking resistance toward this pathological process. Sometimes they floated in the exudative masses but were partly or totally deprived of the fine neural and astrocytic processes which normally surround them. Our findings are interpreted as the ultrastructural correlate of Scholz's “plasmatic infiltration”.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00685300
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  • 32
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    Electronic Resource
    Electron microscopic study of metachromatic leucodystrophy (1969)
    Springer
    Acta neuropathologica 13 (1969), S. 149-156 
    Details
    ISSN: 1432-0533
    Keywords: Electron Microscopy ; Leucodystrophy, Metachromatic ; Enzyme Histochemistry, Electronmicroscopical ; Lysosomes ; Neurochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Dans la leucodystrophie métachromatique, les lipides anormaux s'accumulent dans les lysosomes des cellules gliales et des phagocytes. Les inclusions lipidiques les moins organisées sont les plus riches en phosphatases acides. Celles dont l'ultrastructure est prismatique ont une activité enzymatique très faible et semblent plus proches de corps résiduels que de lysosomes actifs. Il semble que l'absence d'arylsulfatase lysosomiale induise la persistance des sulfatides accumulés dans les lysosomes alors que les autres lipides provenant de la dégénérescence myélinique, seraient normalement catabolisés. Un remaniement progressif de l'ultrastructure du contenu des lysosomes en est la conséquence.
    Notes: Summary In metachromatic leucodystrophy abnormal lipids are stored within the lysosomes of the glial cells and phagocytes. The lipid inclusions which are the less structured are the richest in acid phosphatases. Those of which the ultrastructure is prismatic show a very low enzymatic activity and are more similar to residual bodies than to active lysosomes. It appears that the lack in lysosomal arylsulfatase leads to an accumulation of the sulfatide moiety of the stored lipids while the other lipids originating from the myelin breakdown, would be normally catabolized. This leads to a progressive transformation of the ultrastructure of the lysosome contents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687027
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  • 33
    Electronic Resource
    Electronic Resource
    Electron microscopic observations in mice infected with Japanese encephalitis (1969)
    Springer
    Acta neuropathologica 13 (1969), S. 169-181 
    Details
    ISSN: 1432-0533
    Keywords: Japanese Encephalitis ; Experimental ; Electron Microscopy ; Virus Particles in Neurons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Groß- und Kleinhirnrinde, Plexus chorioideus und Rückenmark von Mäusen wurden nach intracerebraler Inoculation einer Hirnemulsion mit Virus der Encephalitis japonica (JEV) elektronenoptisch untersucht, um den Ort der JEV-Replikation zu bostimmen. 72 Std nach der Inoculation bei Beginn der encephalitischen Symptome enthielten 70 bis 80% aller Rindenneurone und Vorderhornzellen viele sphärische Partikel, die meist im zarten endoplasmatischen Reticulum (EPR) und vereinzelt im granulären EPR lokalisiert waren. Die Einzelpartikel zeigten eine gleichförmige Substruktur aus einem elektronendichten zentralen Hof von 25–30 mμ Durchmesser, einer äußeren, weniger elektronendichten Zone und einer äußersten Grenzmembran von 40 mμ Durchmesser. 96 Std nach der Inoculation zeigte das Cytoplasma der Rinden- und Vorderhornneurone sehr viele Vacuolen und Vesiceln. Partikel wurden weit verstreut in den Vacuolen und Vesiceln sowie erstmals im ERP der Sternzellen und Purkinjezellen angetroffen, allerdings in geringerer Zahl. Keine derartigen Partikel wurden in Kontrolltieren und normalen Mäusegruppen angetroffen. Sogenannte eosinophile intranucleäre Einschlüsse in Epithelzellen des Plexus chorioideus zeigten keine derartigen Partikel im Kern oder in den cytoplasmatischen Bläschen. Nachdem keine als JEV identifizierbaren Partikel in Glia- und Endothelzellen nachzuweisen waren, wird angenommen, daß das JEV echt neurotrop ist und sich im EPR der Nervenzellen repliziert.
    Notes: Summary Cerebral and cerebellar cortices, choroid plexus and spinal cord of mice, inoculated intracerebrally with a brain emulsion containing Japanese encephalitis virus (JEV), were studied electronmicroscopically to determine the cell type and the site of JEV replication. 72 hours after inoculation, when the mice began to show encephalitic symptoms, 70 to 80% of all cortical neurons and anterior horn cells contained many spherical particles mostly located in the smooth endoplasmic reticulum and a few in the granular endoplasmic reticulum. The individual particles demonstrated an uniform substructure consisting of an electron dense central core of 25–30 mμ diameter, an outer less electron dense zone and an outermost limiting membrane of 40 mμ diameter. 96 hours after inoculation, the cytoplasm of cortical neurons and anterior horn cells was observed to contain very many vacuoles and vesicles. Particles were found widely scattered throughout the vacuoles and vesicles, and were observed for the first time in the endoplasmic reticulum of the stellate neurons and in Purkinje cells, though fewer. No such particles were observed in control and normal mouse groups. So-called eosinophic intranuclear inclusions of epithelial cells of choroid plexus failed to show any particles in their nuclei or cytoplasmic vesicles. Considering that no particulate matter, identifiable as JEV, was identified within any of the glial cells or endothelium in this examination, it was concluded that JEV was really neurotropic and replicates in the endoplasmic reticulum of the neurons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687029
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  • 34
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    Electronic Resource
    Changes at the nodes of ranvier during wallerian degeneration: an electron microscope study (1969)
    Springer
    Acta neuropathologica 14 (1969), S. 237-249 
    Details
    ISSN: 1432-0533
    Keywords: Electron Microscopy ; Wallerian Degeneration ; Nodal Changes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wird über ultrastrukturelle Veränderungen in den Ranvierschen Knoten des N.suralis der Ratte im Laufe der Wallerschen Degeneration berichtet. Die Untersuchungen erfolgten 12 und 120 Std nach einer örtlichen Quetschungsverletzung. Die ersten bemerkbaren Veränderungen finden sich im Axon. Nodale und paranodale Anhäufungen von Mitochondrien, multivesikulären und lamellären Körpern, wie auch kleinen blasen- und röhrenartigen Bildungen sind teilweise in den Knoten sichtbar und am deutlichsten nach 24–36 Std erkennbar. Gleichzeitig erfolgt eine Aufsplitterung der Neurofilamente und Neurotubuli, die ihre Liniengestaltung verlieren und sich zusammenballen. Die Zone der erhöhten Dichte gerade unterhalb des nodalen Axolemmas bleibt erhalten. Veränderungen im Myelin beginnen etwas später und bestehen in einem vesikulären Verfall der Endomyelinlamellen und einer Trennung der Endomyelinschlaufen vom Axolemma durch Schwannzellenfortsätze. Dieser Vorgang schien mit einem Zurückziehen des Myelins vom Knoten im Zusammenhang zu stehen. Schwannzellenfortsätze erstrecken sich auch so weit, daß sie das nodale Axon bedecken, wobei sie die nodalen Schwannzellenfortsätze vom Axolemma trennen. Das Endstadium ist die Unterbrechung des nodalen Axons und die Verschmelzung der Myelinenden als Teil der Ovoidbildung.
    Notes: Summary Observations are reported on the ultrastructural alterations at the nodes of Ranvier in the rat sural nerve during the course of Wallerian degeneration. These were examined between 12 and 120 hours after a localized crush injury. The earliest detectable changes are in the axon. Nodal and paranodal accumulations of mitochondria, multivesicular bodies, lamellar bodies and small vesicular and tubular profiles are seen at a proportion of the nodes and are most evident at 24–36 hours. Concomitantly with this, the neurofilaments and neurotubulus fragment, lose their alignment and clump together. The zone of increased density just beneath the nodal axolemma is preserved. Changes in the myelin begin slightly later and consist of vesicular breakdown of the terminal myelin lamellae, and separation of the terminal myelin loops from the axolemma by Schwann cell processes. The latter event appeared to be associated with retraction of the myelin from the node. Schwann cell processes also extend to cover the nodal axon, separating the Schwann cell nodal processes from the axolemma. The final stage is the interruption of the nodal axon and the fusion of the ends of the myelin as part of ovoid formation.
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    URL: http://dx.doi.org/10.1007/BF00685303
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  • 35
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    Electronic Resource
    Electron histochemical demonstration of gangliosides in normal and Tay-Sachs brain tissue (1969)
    Springer
    Acta neuropathologica 13 (1969), S. 157-168 
    Details
    ISSN: 1432-0533
    Keywords: Gangliosides ; Tay-Sachs Disease ; Brain Subcellular Localization ; Hale Stain ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Reaktion von kolloidalem Eisen mit Sialomucinen (Hale stain) wurde zur elektronenmikroskopischen Darstellung der neuraminsäurehaltigen Ganglioside in den subcellulären Fraktionen des Gehirns angewandt. Zunächst wurde mit Hilfe tritiummarkierter Ganglioside überprüft, ob bei der Gewinnung subzellulärer Fraktionen Ganglioside nicht unspezifisch subcellulär adsorbiert werden. Eine nennenswerte Adsorption konnte ausgeschlossen werden. Das Verfahren wurde zuerst auf die aus Meerschweinchengehirnen isolierten Fraktionen angewandt. Da Nervenendigungen, Mitochondrien und Synapsenbläschen Hale-positiv reagierten, dienten Enzyminkubationen mit Neuraminidase und Hyaluronidase zur Differenzierung von anderen Hale-positiven sauren Substanzen. Schließlich wurde die Methode auf die cytoplasmatischen multilamellären Körperchen (MCB) übertragen, die aus Gehirnen an Tay-Sachs'scher Krankheit Verstorbener isoliert wurden. Aus den Versuchen konnte abgeleitet werden, a) daß die Hale-Färbung auch Ganglioside anfärbt, b) daß Ganglioside auf der Oberfläche der Membran von den multilamellären Körperchen und mit hoher Wahrscheinlichkeit auch auf der Membran der Nervenendigungen lokalisiert sind, c) daß die Synapsenbläschen eine positive Reaktion ergeben, die jedoch nicht mit Sicherheit auf vorhandene Ganglioside zurückgeführt werden kann, d) daß die äußere Mitochondrienmembran Hale-positive Substanzen enthält, deren Natur unbekannt ist.
    Notes: Summary The reaction of colloidal ferric oxide with sialomucins (Hale stain) was applied to sialic acid-containing gangliosides in subcellular fractions of the brain, in order to investigate their localization by electron microscopy. Prior to all experiments, a check was made, by means of tritium-labeled ganglioside, to confirm that the ganglioside content in the subcellular particles was not the result of an unspecific adsorption during the isolating procedure. No considerable unspecific adsorption could be registered. Hale stain was first applied to subcellular fractions obtained from guinea-pig brains. Since nerve-endings, mitochondria and synaptic vesicles gave a positive staining reaction, incubations with neuraminidase and hyaluronidase were carried out in order to achieve a differentiation. Finally, the method was applied to the membranous cytoplasmic bodies (MCB) which were isolated from the brain of a patient with Tay-Sachs disease. It was concluded that: a) Hale stain stains gangliosides also, b) gangliosides are localized in the membrane of membranous cytoplasmic bodies and also very probably in the membrane of nerve-endings, c) synaptic vesicles give a Hale-positive reaction which cannot with certainty be attributed to gangliosides, d) the outer membrane of mitochondria contains Hale-positive substances, the nature of which is not known.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687028
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  • 36
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    Electronic Resource
    An electron microscopic study of meningiomas (1969)
    Springer
    Acta neuropathologica 13 (1969), S. 301-323 
    Details
    ISSN: 1432-0533
    Keywords: Meningiomas ; Electron Microscopy ; Endotheliomatous, Fibromatous Type ; Light Cells ; Dark Cells ; Histogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 17 chirurgisch entfernte Meningiome vom endotheliomatösen und 5 vom fibromatösen Typ wurden elektronenmikroskopisch untersucht. Unterschiede im Entwicklungsgrad der cytoplasmatischen Fortsätze und der Beziehungen zwischen den Plasmamembranen der Tumorzellen wurden in den endotheliomatösen Meningeomen beobachtet. In 4 fibromatösen Tumoren sind die zelligen Areale von bindegewebigen Räumen umgeben. Auch wenn die meisten Tumorzellen helle Zellen sind und sich nicht wesentlich von den Tumorzellen der endotheliomatösen Meningiome unterscheiden, ist die histologische Anordnung der fibromatösen klar von derjenigen der endotheliomatösen Meningeome zu trennen. Ausschlaggebend dafür ist die starke Entwicklung des Bindegewebes. Die Dunkelzellen lassen sich in zwei Typen gliedern: Typ I wird in vier Tumoren mit stark ausgebildetem Bindegewebe angetroffen. Die Analyse der inneren Zellstruktur sowie das Vorliegen von Übergängen zwischen hellen und dunklen Zellen machen es wahrscheinlich, daß diese nur verschiedene Typen einer einzigen Ursprungszelle darstellen. Die Bedeutung dieser verschiedenen Erscheinungsformen der Meningiomzellen wird diskutiert. Die Ultrastruktur der Tumorzellen ähnelt derjenigen der normalen arachnoidalen Zellen. Rückschlüsse auf die blastodermale Herkunft der normalen und tumoralen meninigalen Zellen auf Grund ihrer ultrastrukturellen Merkmale erscheinen verfrüht.
    Notes: Summary Seventeen surgically removed meningiomas of the endotheliomatous and five of the fibromatous type were investigated with an electron microscope. Differences of the development of cytoplasmic processes and the relations between plasma membranes of blastomatous cells were observed in endotheliomatous meningiomas. In four of the fibromatous tumors the cell groups were surrounded by spaces of connective tissue. Although most of the tumor cells were light cells and are not essentially different from the tumor cells of the endotheliomatous meningiomas, the histological structure of fibromatous meningiomas is clearly distinguished from the endotheliomatous type, because of the greater amount of connective tissue. The dark cells may be divided into two types: the first was found in those four tumors, where the connective tissue is well developed, while the second one only occurred in one of the tumors. The analysis of the inner cell structure as well as the presence of interstages between dark and light cells makes it probable that dark and light cells are different types of one original cell. The cause of this different appearance of the menigioma cells is discussed. The fine structure of the tumor cells showed a great similarity with that of normal arachnoidal cells. Conclusions on the blastodermic origin of normal and blastomatous meningial cells on the basis of ultrastructural characteristics, however, seem to be premature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00686120
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    Electronic Resource
    Abnormal sarcolemmal nuclei encountered in several cases of dystrophia myotonica (1969)
    Springer
    Acta neuropathologica 12 (1969), S. 183-188 
    Details
    ISSN: 1432-0533
    Keywords: Dystrophia myotonica ; Electron Microscopy ; Sarcolemmal Nuclei ; Myofibrillar Material
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung In fünf Fällen von Dystrophia myotonica zeigte die elektronenoptische Untersuchung von bioptisch entnommenem Material zentrale und subsarkolemmale Kerne, die komplexe vacuoläre Areale um myofibrilläres Material enthalten. Diese bisher nicht beobachtete Veränderung könnte durch Verlagerung von myofibrillärem Material in den Kern während seiner Wanderung in das Faserzentrum durch Invagination, aber nicht Durchbrechung der Kernmembran bedingt sein.
    Notes: Summary In five cases of dystrophia myotonica electron microscope preparations of muscle taken at biopsy showed both centrally placed and subsarcolemmal nuclei containing complex vacuolar areas enclosing myofibrillar material. It is suggested that this appearence, which has not been seen in any other condition, may be due to the forcing of myofibrillar material into the nucleus during its migration to the centre of the fibre invaginating but not breaching its membrane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00692505
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  • 38
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    Electronic Resource
    Light and electron microscopic study of the muscles in hypokalemic periodic paralysis (1969)
    Springer
    Acta neuropathologica 12 (1969), S. 329-338 
    Details
    ISSN: 1432-0533
    Keywords: Hypokalemic Periodic Paralysis ; Electron Microscopy ; Myopathy ; Sarcoplasmic Reticulum ; Glycogen, Muscular
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Licht- und elektronenoptische Untersuchungen wurden an Muskelbiopsien von 4 Fällen hypokaliämischer periodischer Paralyse durchgeführt. Die frühesten Veränderungen betreffen nach Meinung der Verfasser das sarkoplasmatische Reticulum: Vacuolisierung des Längssystems und vermutlich Multiplikation des Quersystems. Es wird vermutet, daß die Vacuolenbildung die Folge einer Fusion der Vesikeln des Quersystems darstellt. Destruktion von Myofibrillen und Vergrößerung der, interfibrillären Räume treten erst in späteren Phasen des Krankheitsprozesses auf. Ausdehnung und Intensität dieser Veränderungen bedingen das typische histologische Bild myogener Läsionen bei Fällen m klinisch fixierten Symptomen der Myopathie.
    Notes: Summary Light and electron-microscopic studies were performed on the muscles taken from 4 cases with hypokalemic periodic paralysis. The authors conclude that the earliest changes concern the sarcoplasmic reticulum: vacuolisation of the longitudinal system and probably, multiplication of the transverse system. It is suggested, that vacuoles are formed as a result of fusion of the vesicles of the transverse system. Destruction of myofibrilles and enlargement of the interfibrillar spaces appear at a later period of the disease process. Extensive and intensive changes of that kind present a typical appearance of myogenic changes in histological study observed in the cases with clinically fixed symptomes of myopathy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00809129
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  • 39
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    Electronic Resource
    Ultrastructural and histochemical studies of cortical biopsies in subacute dementia (1969)
    Springer
    Acta neuropathologica 13 (1969), S. 43-55 
    Details
    ISSN: 1432-0533
    Keywords: Subacute Dementia ; Jakob-Creutzfeldt Disease ; Brain Biopsy ; Histochemistry ; Electron Microscopy ; Basement Membrane ; Astroglia Dilatation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die elektronenoptische und histochemische Untersuchung von Biopsiematerial bei zwei Fällen subakuter Demenz ergab Neurone mit reichlich Lipofuscin-Depots sowie erhöhter saurer Phosphatase-Aktivität. Obwohl diese Veränderungen eine Nervenzellerkrankung anzeigen dürften, werden sie wegen ihrer Ähnlichkeit sowie wegen des Vorliegens anderer, spezifischerer Zellveränderungen als Sekundärphänomene gedeutet. Im ersten Fall wird als primäre Läsion eine Verdickung der Basalmembran der Gefäße, im zweiten Fall eine Astrogliaschwellung angenommen. Da diese Strukturen wichtige Transportfunktionen haben dürften, könnten diese Anomalien leicht die neuronale Versorgung stören und dadurch die neuronalen Läsionen verursachen. Die Bedeutung des Glykogens in diesen Strukturen wird diskutiert.
    Notes: Summary The electron microscopic and histochemical findings in biopsies of two cases of subacute dementia have revealed neurons containing numerous lipofuscin bodies and increased acid phosphatase. Although these changes are considered to indicate neuron disease, they are believed to represent a secondary process because of their similarity and because other more distinctive cell alterations are present. In the first case, the primary abnormality is believed to be thickening of the vascular basement membrane, while in the second case, astroglial dilatation is considered a primary change. Since these structures appear to have important transport functions, these abnormalities could easily impair the nutrient supply to neurons and, in this way, produce the neuronal alteration. The significance of glycogen in these tissues is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00686140
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  • 40
    Electronic Resource
    Electronic Resource
    Ultrastructural study of a nerve biopsy from a case of early infantile chronic neuropathy (1969)
    Springer
    Acta neuropathologica 13 (1969), S. 131-142 
    Details
    ISSN: 1432-0533
    Keywords: Neuropathy, Chronical ; Hypertrophic Neuritis ; Schwann-Cell ; Onion Bulb ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die wesentlichen Veränderungen bei dem mitgeteilten Fall von chronischer frühinfantiler Neuropathie bestehen in einer Modifikation der Schwann-Zellen, die zur Bildung eines konzentrischen Netzwerkes von Lamellen führt. Dieses wird durch eine doppelkonturierte Hülle der Basalmembran um zahlreiche große bemarkte und unbemarkte Fasern gebildet. Die Anomalien der Markscheiden sowie die Häufigkeit von Desmosomen sind bemerkenswert. Diese Besonderheiten unterscheiden diesen Fall von anderen, bisher beschriebenen chronischen Neuropathien. Trotzdem erscheint es derzeit nicht möglich, eine Aussage über die Spezifität der ultrastrukturellen Befunde am untersuchten Nerven zu treffen.
    Notes: Summary The principal lesion in this case of chronic early infantile neuropathy is a modification of the Schwann cell resulting in the formation of a concentric network of lamellae formed by a double-layered sheet of basement membrane around numerous, large myelinated and unmyelinated fibers. The abnormalities in the myelin sheaths and the frequency of desmosomes are noteworthy. These peculiarities distinguish this case from other chronic neuropathies described up to now. Nevertheless, it is impossible to say at present whether the ultrastructural aspect of the nerve studied here is in any way specific.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687025
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  • 41
    Electronic Resource
    Electronic Resource
    Granulomatous encephalitis in Whipple's disease (1969)
    Springer
    Acta neuropathologica 13 (1969), S. 1-11 
    Details
    ISSN: 1432-0533
    Keywords: Whipple's Disease ; Granulomatous Encephalitis ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Von 21 Fällen von Whipplescher Krankheit in der Sammlung des Armed Forces Institute of Pathology zeigten 4 Fälle neurologische Symptome mit besonders ausgeprägten Hirnläsionen. Lichtmikroskopisch bestanden die Herde aus knötchenförmigen Anhäufungen von Makrophagen, deren Cytoplasma mit Hämatoxylin-Eosin eine charakteristische schwachblaue und nach Durchführung der Perjodsäure-Schiff-Reaktion eine stark rote Färbung zeigte. Elektronenmikroskopisch fanden sich in den Hirnläsionen Bacillen, die morphologisch den im Darm beschriebenen glichen und die auch dieselben Degenerationserscheinungen aufwiesen. Die Perjodsäure-Schiff-Reaktion färbt Kapselmaterial und Zellwände,die auch nach Untergang der Bacillen noch nachweisbar sind. Diese Beobachtungen werden als weiterer Beweis für die infektiöse Ätiologie der Whippleschen Krankheit angeführt.
    Notes: Summary Among the 21 autopsied cases of Whipple's disease on file at the Armed Forces Institute of Pathology, 4 had neurological symptoms and prominent involvement of the central nervous system, By light microscopy the lesions were composed of nodular aggregates of macrophages having cytoplasm that stained a distinctive pale blue with hematoxylin-eosin and bright red with the periodic acid-Schiff technique. By electron microscopy the cerebral lesions revealed bacilli morphologically identical to and undergoing the same sequence of degenerative changes as those observed in the intestine. The periodic acid-Schiff reaction stains the walls and the capsular material that persists even after intact organisms disappear. These observations further support the infectious nature of Whipple's disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00686137
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  • 42
    Electronic Resource
    Electronic Resource
    The normal sural nerve in man (1969)
    Springer
    Acta neuropathologica 13 (1969), S. 197-216 
    Details
    ISSN: 1432-0533
    Keywords: Peripheral Nerves ; Axons ; Myelin Sheaths ; Schwann Cells ; Electron Microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Eine kombinierte licht- und elektronenmikroskopische Untersuchung am normalen N. suralis von 7 Menschen im Alter von 15–59 Jahren wurde vorgenommen. Qualitative und quantitative Beobachtungen an Schwann-Zellen und Fibroblasten, markhaltigen und marklosen Fasern wurden an isolierten Faszikeln durchgeführt. Schwannzellen überwiegen gegenüber Fibroblasten im Verhältnis von etwa 9:1. Die meisten Schwannzellen (etwa 80%) liegen an marklosen Fasern. Die Faktoren, welche die Dichte dieser Zellen pro Querschnittsareal beeinflußen, werden diskutiert. Einige ultrastrukturelle Befunde an bemarkten Fasern werden beschrieben und ihre Zahl pro mm2 sowie die Häufigkeitsverteilung ihrer Dicke wird angegeben. Eine indirekte Methode zur Bestimmung der mittleren Internodienlänge für jede der Markfasergrößenpopulationen an Querschnitten von Faszikeln normaler Nerven durch Bestimmung des Verhältnisses der markhaltigen Fasersegmente zu ihrer Kernzahl wird vorgeschlagen. Die Ultrastruktur der marklosen Nervenfaern wird beschrieben und die Identifizierung dieser Axone mit extremen Durchmessern diskutiert. Ihre Dichte und Größenfrequenzhistogramme sind die ersten, die am Menschen durch systematische elektronenoptische Untersuchungen veröffentlicht werden. Das mittlere Verhältnis von marklosen zu bemarkten Fasern ist etwa 3,7:1 und schwankt in den Faszikeln der Einzelindividuen.
    Notes: Summary A combined light and electron microscope study of the normal sural nerve in 7 people aged 15–59 years is reported. Qualitative and quantitative studies of the Schwann cells and fibroblasts, myelinated and unmyelinated fibres are made in isolated fascicles. Schwann cells predominate over fibroblasts in the ratio of about 9-1. Most Schwann cells, almost 80%, are attached to unmyelinated fibres. Factors influencing the densities of these cells per cross sectional area are discussed. Some ultrastructural features of the myelinated fibres are described and their numbers per sq.mm and frequency distribution of their sizes are produced. An indirect method is proposed for assessing the mean internodal length for earch of the myelinated fibre size populations in cross sections of fascicles of normal nerves by estimating the proportion of myelinated segments cut through their nucleus. The ultrastructure of unmyelinated fibres is described and the identification of axons of extreme diameter is discussed. Their densities and size frequency histograms are the first to be reported in man by systematic electron microscope studies. The average ratio of unmyelinated to myelinated fibre density is about 3.7:1 though it varies in the fascicles of the different individuals. The implications of axonal diameter in the presence of myelin are commented on.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00690642
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    Electronic Resource
    Familial spongy degeneration of the central nervous system (Van Bogaert-Bertrand disease) (1969)
    Springer
    Acta neuropathologica 12 (1969), S. 103-115 
    Details
    ISSN: 1432-0533
    Keywords: Spongy Degeneration of the CNS ; Van Bogaert-Bertrand-Disease ; Electron Microscopy ; Astrocytic Mitochondria ; Abnormal Cerebral Edema
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wird über licht- und elektronenoptische Untersuchungen an Muskel-und Hirnbiopsien eines Falles von spongiöser Degeneration des ZNS berichtet. Die in der grauen und weißen Hirnsubstanz enthaltenen Vacuolen entsprechen a) Spalten in den Markscheiden infolge Aufsplitterung an der intraperiodischen Linie und b) geschwollenen Astrocytenperikaryen und-fortsätzen. Ungewöhnliche Mitochondrien mit Gehalt an kristallinem Material fanden sich nur in Astrocyten. Die ultrastrukturellen Befunde entsprechen denen des Hirnödems. Es wird angenommen, daß die Astroglia eine primäre Rolle in der Flüssigkeitsansammlung spielt, während die Markscheidenschwellung als eine Sekundärläsion aufgefaßt wird. Die mögliche Bedeutung abnormer Astrocyten-Mitochondrien wird diskutiert.
    Notes: Summary Light and electron microscopy study of skeletal muscle and cerebral biopsies from a case of spongy degeneration of central nervous system is reported. The multiple vacuoles present in cerebral gray and white matter correspond to (a) clefts within myelin sheaths resulting from splitting at the intraperiod line and (b) swollen astrocytic perikarya and processes. Unusual mitochondria containing crystalline-like material were observed only in astrocytes. The ultrastructural findings are consistent with cerebral edema. It is suggested that the astrocytes play a primary role in the fluid accumulation while the myelin swelling is a secondary lesion. The possible role of the abnormal astrocytic mitochondria is discussed.
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    URL: http://dx.doi.org/10.1007/BF00692500
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  • 44
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    Electronic Resource
    Étude ultrastructurale de quatre cas de leuco-encéphalite sclérosante subaiguë (1969)
    Springer
    Acta neuropathologica 14 (1969), S. 1-13 
    Details
    ISSN: 1432-0533
    Keywords: Subacute Sclerosing Leucoencephalitis ; Electron Microscopy ; Tubular Inclusions ; Inclusion Bodies (Cristalline Rods, Fibrillar Bundles, Nuclear Bodies, Osmiophilic Particles)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Les auteurs rapportent 4 observations caractéristiques de LESS: L'analyse ultra-structurale montre: 10 — des inclusions tubulaires intra-nucléaires neuronales ou gliales et intra-axonales de morphologie superposable à celle des nucléocapsides des myxo-virus, de la rougeole en particulier. 20 — des formations non spécifiques: corps nucléaires, faisceaux cristallins et fibrillaires traduisant un trouble métabolique nucléaire, particules osmiophiles liées à une hyperactivité cellulaire. Les inclusions tubulaires virales sont présentes quelque soit la durée de la maladie (3 mois à 5 ans) indiquant l'absence d'autostérilisation virale dans le S.N.C. La LESS apparaît liée au virus rougeoleux mais le mécanisme indirect immunitaire ou métabolique de cette action est inconnu.
    Notes: Summary Four cases of S.S.L.E are reported. The electron microscopy findings show: 1. Tubulary inclusion bodies: They appear in three cases out of four, either in neuronal and glial nucleus or in axis cylinders. Their morphological features are similar to the nucleocapsides of myxoviruses and particularly measles-virus. 2. Other different types of nonspecific inclusions: nuclear bodies, cristalline-like rods and fibrillar bundles which may be considered as the result of a nuclear metabolic disorder, osmiophilic particles which may be seen as the result of a cellular intracytoplasmic hyperactivity. The tubules are found whatever the duration of the disease (3 months up to 5 years) may be. This might indicate that there is no autosterilization of the virus in the C.N.S. during the course of S.S.L.E. According to the most recent papers, such a disease might be interpreted as an infection indirectly induced by measles-virus with an unknown immunologic or metabolic mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687698
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  • 45
    Electronic Resource
    Electronic Resource
    Electron microscope study of the rat brain with experimental sodium azide intoxication (1969)
    Springer
    Acta neuropathologica 14 (1969), S. 185-193 
    Details
    ISSN: 1432-0533
    Keywords: Hypoxia ; Sodium Azide ; Electron Microscopy ; Ferritin ; Capillary Permeability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Experimentelle histotoxische Hypoxämie wurde in Ratten durch Natriumacid-Vergiftung erzeugt. Die mikroskopische Untersuchung der Hirne ergab keine Veränderung, aber bei der elektronenmikroskopischen Untersuchung fanden sich als Frühveränderungen in der Hirnrinde und im Subcortex eine Erweiterung der intercellulären Räume und eine Anschwellung der pericapillären Astrocytenfortsätze. Ferritinalbumin-Mischung, die als Indicator des Eiweißtransportes benutzt wurde, zeigte keine Vermehrung der Capillarpermeabilität. Es wird vermutet, daß Natriumacid den Wasserstoffwechsel beeinträchtigt, wobei es eine osmotische Ausgleichstörung im Gehirn erzeugt.
    Notes: Summary Histotoxic hypoxia was experimentally produced in the rat brain by sodium azide intoxication. In spite of the absence of light microscopic alterations, electron micrographs showed the early changes in the cerebral cortex and subcortex which consisted of widening of the intercellular space and swelling of the pericapillary astrocytic end-feet. However, ferritin-albumin mixture, used for the tracer of protein transport, did not show any increase in the capillary permeability. Sodium azide was considered to disturb the water metabolism, producing osmotic unbalance in the brain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00685298
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  • 46
    Electronic Resource
    Electronic Resource
    Effects of LSD on the spontaneous and evoked activity of retinal and geniculate ganglion cells (1969)
    Springer
    Psychopharmacology 15 (1969), S. 382-391 
    Details
    ISSN: 1432-2072
    Keywords: LSD ; Retina ; LGN ; Single Unit Activity ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of LSD 25 (i. v. injection) on the spontaneous and evoked activity of the visual system was investigated in cats. 50 γ/kg did not change significantly the ERG and the visual cortical evoked potential. The spontaneous discharge rate of 14 out of 21 retinal ganglion cells showed an increase which reached its maximum within 20–30 min and which could still be present 1 hour following the injection. One third of the retinal units showed a slight depression of their spontaneous dischaRge rate with about the same time course. Single units of the LGN showed about the same behaviour. The response to light stimulation was slightly increased in some units and light induced inhibition was slightly shortened. The possible mechanism of the LSD-effect on retinal ganglion cell activity is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00403713
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  • 47
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    Electronic Resource
    Langfristige Verträglichkeitsprüfung mit Benperidol an der Katze (1969)
    Springer
    Psychopharmacology 14 (1969), S. 164-166 
    Details
    ISSN: 1432-2072
    Keywords: Benperidolum ; Cat ; Extrapyramidal Side Effect ; EEG ; Toxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Daily doses of 1–10 mg Benperidol were given perorally to cats during 26 months. The general behaviour and the EEG were unchanged during the treatment, in particular no signs of dyskinesia were observed. After discontinuation of the administration, the behaviour and the EEG of the animals stayed normal. Thus no lasting and irreversible side effects could be observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00403690
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  • 48
    Electronic Resource
    Electronic Resource
    Responses of neurones in cat's abducens nuclei to horizontal angular acceleration (1969)
    Springer
    Pflügers Archiv 309 (1969), S. 285-309 
    Details
    ISSN: 1432-2013
    Keywords: Labyrinthine Stimulation ; Types of Abducens Neurones ; Frequency Analysis ; Cat ; Labyrinthreizung ; Abducensneurone ; Frequenzanalyse ; Katze
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Single cell activity was recorded extracellularly from neurones in cat's abducens nuclei in unanesthetized, decerebrate preparations. Two types of neurones were found. i) The motoneurones (type IIA) increased their firing linearly or exponentially to contralateral constant angular accelerations and decreased firing to ipsilateral rotation. The increased frequency was maintained at a constant level without any sign of adaptation. This constant level of maximum frequency was proportional to the logarithm of the acceleration applied. No significant differences of the frequency responses of tonic and silent motoneurones were found. The conduction velocities of the axons of spontaneously firing type IIA cells were slower than in silent neurones. Electrical stimulation of the contralateral VIIIth nerve led to activation of the type IIA cells; stimulation of the ipsilateral nerve resulted in inhibition of both spontaneous discharge and antidromic invasion of the motoneurones. ii) The type IA units increased their firing rate to ipsilateral rotation and ceased to discharge in response to contralateral rotation. They never were excited antidromically by stimulation of the VIth nerve. However, they were excited by stimulation of the ipsilateral VIIIth nerve. Their possible functional role in the vestibulo-ocular system was discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00587754
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  • 49
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    Electronic Resource
    Die Rolle „spezifischer” und unspezifischer Afferenzen für den Antrieb der Atmung, untersucht durch Reizung und Blockade von Afferenzen an der decerebrierten Katze (1969)
    Springer
    Pflügers Archiv 312 (1969), S. 189-205 
    Details
    ISSN: 1432-2013
    Keywords: Cat ; Decerebration ; Afferents to Respiratory Centers ; Medulla Oblongata ; Reticular Formation ; Katze ; Decerebrierung ; Afferenzen zu Atemzentren ; Medulla oblongata ; Formatio reticularis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung An 11 intercolliculär decerebrierten Katzen wurde geziegt, daß Kälteblockade eines eng umschriebenen Feldes auf der ventralen Oberfläche der Medulla oblongata, wie früher für anaesthesierte Tiere beschrieben, zu Atemstillstand führt, wenn die kontralaterale Stelle auf der Medulla oblongata, die Sinusnerven und die Vagi ausgeschaltet sind. Zu Atemstillstand kam es auch, wenn statt der Kälteblockade 2% Novocain durch lokale Superfusion bei gleichzeitiger Gegenspülung der Umgebung mit künstlichem Liquor angewandt wurde, oder wenn ein mit 1% Novocain getränkter Tupfer lokal aufgelegt wurde. Außerdem führte Kälteblockade zu Atemstillstand, wenn durch kontinuierliche auch während der Kälteblockade anhaltende elektrische Reizung eines N. femoralis oder hinterer Lumbalwurzeln an decerebrierten Katzen oder des Hypothalamus an einer anaesthesierten Katze Steigerungen der Ventilation ausgelöst worden waren. Elektrische Reizung eines Sinusnerven führte zu Atemsteigerungen. Bei Sinusnervenreizung während eines durch Kälteblockade ausgelösten Atemstillstands kam es zu rhythmischer Atmung. Aus diesen Untersuchungen wird geschlossen, daß mit der Ausschaltung der beschriebenen Felder auf der ventralen Oberfläche der Medulla oblongata am sonst desafferentierten Tier die Gesamtheit der für die zentrale CO2-Empfindlichkeit verantwortlichen Strukturen erfaßt ist, daß nach Ausschaltung der zentralen und der peripheren Chemosensibilität eine unspezifische Aktivierung der Atmungszentren unwirksam ist und daß die Atmungszentren zur Ausbildung einer rhythmischen Atmung von spezifischen Antrieben abhängig sind.
    Notes: Summary It was shown in 11 decerebrated cats, that cooling of a small and well defined area on the ventral surface of the medulla will cause respiratory arrest if the contralateral area of the medulla, the vagi and sinus nerves are eliminated. This confirms earlier observations obtained in anesthetized cats. Apnea was also produced by local superfusion of 2% procain with simultaneous flushing of the immediate surrounding area with mock spinal fluid. Local application of a small sponge soaked with 1% procain had the same effect. Electrical stimulation of femoral nerves or posterior roots which results in hyperventilation on the decerebrated cat failed to show any effect during periods of cold blockade. There was no respiratory response to direct stimulation of the hypothalamus in an anesthetized cat during cooling. Electrical stimulation of one sinus nerve caused an increase of ventilation. Sinus nerve stimulation during apnea induced by cold blockade resulted in rhythmical respiration. It is concluded from these experiments: Blocking of the area under discussion on the ventral surface of the medulla, inhibits all structures responsible for the central CO2-sensitivity in the deafferentiated animal. There was no response to non-specific stimuli of the respiratory center after elimination of central and peripheral chemosensitivity. The respiratory centers apparently depend on specific stimuli to support rhythmical respiration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00586928
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    Räumliche summation im receptiven feldzentrum von neuronen des geniculatum laterale der katze (1969)
    Springer
    Experimental brain research 8 (1969), S. 53-65 
    Details
    ISSN: 1432-1106
    Keywords: Lateral geniculate body ; Spatial summation ; Off-center-characteristics ; Geniculate transfer ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 1. Die räumliche Summation im receptiven Feldzentrum von Neuronen des Corpus geniculatum laterale (CG-L) wird beschrieben und mit entsprechenden Untersuchungen an retinalen Ganglienzellen verglichen. Neben größerer interneuronaler Variabilität ergeben sich ausgeprägtere Unterschiede der Summationseigenschaften der on-und off-Zentrum-Neurone. Der effektive Summationsbereich von etwa 1/5 der Fläche des RFZ ist in Retina und CGL etwa gleich. 2. Die on-Zentrum-Neurone des CGL zeigen in beiden Adaptationszuständen einen ähnlichen Summationsverlauf wie in der Retina. Das Entladungsnieau ist im CGL jedoch erheblich geringer und nicht durch Unterschiede in der Spontanaktivität zu erklären. 3. Die Mehrzahl der off-Zentrum-Neurone des CGL zeigt bei DA inverse Summationsverläufe wie in der Retina: durchgehende Verminderung der Entladungsrate der off-Antworten bei Vergrößerung der Reizfläche im RFZ. Eine kleine Gruppe zeigt einen parabelförmigen Summationsverlauf mit Entladungszunahme bis zu Reizflächen von 10–30% der Fläche des RFZ und darauffolgender Entladungsminderung. Bei Helladaptation zeigen fast alle off-Zentrum-Neurone diesen Parabelverlauf. Das durchschnittliche Entladungsniveau ist von dem retinaler offZentrum-Neurone nicht signifikant verschieden. 4. Die interneuronale Variabilität der Summationsvorgänge im RFZ von CGLNeuronen ist gegenüber den retinalen Ganglienzellen deutlich größer. Dies gilt insbesondere für die off-Zentrum-Neurone. Das Summationsverhalten von CGLNeuronen läßt sich daher nicht wie in der Retina durch einen Funktionstyp beschreiben. 5. Die Befunde sprechen für eine Transformation des retinalen Eingangs der off-Zentrum-Neurone im CGL, während die on-Zentrum-Neurone außer der bekannten Frequenzuntersetzung keine wesentliche Umformung erkennen lassen.
    Notes: Summary 1. Spatial summation in the receptive field center of neurones of the lateral geniculate body (CGL) is limited by inhibition to a small part of field center. Variations of stimulus size are only effective if the stimulus is smaller than about 1/5 of the area of receptive field center. Thus, the active summating area of the field center in the CGL corresponds to that of the retina. Geniculate neurones, however, show less homogeneous responses and the summation properties of the two neuronal subsystems (on-center-and off-center-cells), show greater differences than in the retina. 2. The form of summation curves for the on-center-neurones of the CGL is similar to those of the retina at both adaptation levels. However, the average responses rates in the CGL are considerably lower. This is not due to differences of spontaneous activity. 3. The summation characteristics of off-responses of off-center-neurones of the CGL are quite different from those in the retina. In dark adaptation the majority of CGL neurones respond with decreasing discharge rates to increasing spot-sizes within the field center. A small number show an initial increase of discharge rates up to stimulus sizes of about 1/10 of the receptive field center before a decrease occurs. This parabolic summation type is typical for most off-center-neurones in light adaptation. The mean discharge levels are the same as those of the retinal offcenter-neurones. 4. The higher interneuronal variability of summation curves especially of the off-center-neurones of the CGL indicates a more complex determination of the discharge properties of CGL neurones. This functional differentiation of single neurones is congruent with the more complex structural and synaptic organisation in CGL. 5. With respect to spatial summation, the results indicate a transformation of the retinal input of the off-center-neurones at the geniculate level, whereas the oncenter-neurones are nearly unchanged.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234925
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    Räumliche summation und hemmungsvorgänge im receptiven feldzentrum von retina-neuronen der katze (1969)
    Springer
    Experimental brain research 8 (1969), S. 37-52 
    Details
    ISSN: 1432-1106
    Keywords: Retinal Ganglion Cells ; Spatial Summation ; Center Inhibition ; Dynamic Organisation of Receptive Fields ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 1. An retinalen Ganglienzellen der Katze wurde die räumliche Summation im receptiven Feldzentrum (KFZ) bei Dunkeladaptation und Helladaptation durch mittelpunktzentrierte Lichtreize verschiedener Flächengrößen untersucht. Als Kriterium dienten die Entladungsraten der ersten 200 und 500 msec nach Licht-an oder Licht-aus. Das Summationsverhalten wurde sowohl für Einzelneurone als auch gruppenstatistisch für die beiden Neuronen-Systeme B (on-Zentrum) und D (off-Zentrum) untersucht. 2. Die räumliche Summation ist auf den inneren Bereich des RFZ beschränkt: bei on-Zentrum-Neuronen steigt die Entladungsrate nur bis zu Reizflächen, die etwa 1/5 der Fläche des RFZ belichten, bei off-Zentrum-Neuronen bis zu Reizflachen von ca. 1/10 des RFZ. Bei Variation der Reizfläche zwischen 20 und 100% der Fläche des RFZ bleibt das Entladungsniveau konstant (asymptotischer Verlauf der Summationskurve). 3. Die Begrenzung der räumlichen Summation auf einen kleinen Bereich des RFZ beweist eine bereits im Feldzentrum wirksame Hemmung. Diese Zentrum-Inhibition begrenzt die Erregungssummation im RFZ bei zunehmender Flächengröße des Lichtreizes. 4. On- und off-Zentrum-Neurone unterscheiden sich in beiden Adaptationszuständen in der Höhe des Entladungsniveaus. Die Entladungsraten der on-Zentrum-Neurone nach Licht-an übertreffen um ein Mehrfaches die Entladungsraten der off-Zentrum-Neurone nach Licht-aus. Die Unterschiede sind gruppenstatistisch hoch signifikant. Die interneuronale Variabilität der Entladungsraten ist bei den onZentrum Neuronen erheblich geringer als bei den off-Zentrum-Neuronen. 5. Dunkel -und Helladaptation führt zu signifikantem Unterschied der Entladungsraten: bei Helladaptation liegt die Impulsrate beider Neuronentypen höher als bei Dunkeladaptation und der Summationsbereich ist um 5–10% größer. 6. Für die mathematische Beschreibung der Summationsverläufe ist die Hyperbel besser geeignet als die logarithmische und Potenzfunktion. Logarithmus- und Potenzfunktionen beschreiben den konstanten asymptotischen Teil der Summationskurven ungenügend und eigenen sich nur für den Kurventeil im innersten Summationsbereich. Die Bedeutung der Befunde für eine dynamische Interpretation der visuellen Feldorganisation und mögliche Beziehungen zur lateralen Umfeldhemmung werden diskutiert.
    Notes: Summary 1. Spatial summation of suprathreshold light stimuli within receptive field centers (RFZ) of retinal ganglion cells was investigated during dark and light adaptation in cats. The mean discharge rates for 200 and 500 msec following light on or off were the computed response criteria. The summation effects were analyzed for single neurones and statistically for grouped neuron populations of the two neuronal subsystems B (on-center-neurones) and D (off-center-neurones). 2. Spatial summation is restricted to a small part of the RFZ. On-centerneurones increase their on-discharge rates with increasing spot sizes, only if the stimulus illuminates less than 1/5 of the RFZ. The summating area of the off-centerneurones is smaller (about 1/10 of the RFZ). 3. The limitation of spatial summation to a small part of the RFZ indicates the existance of inhibition within the RFZ. This center-inhibition sets a constant limit for excitation summation in the RFZ. 4. The mean neuronal response rates for the 2 subsystems show significant differences: The on-discharges of the on-center-neurones exceed the off-discharges of the off-center-neurones by a factor of 3–5. These highly significant differences occur at both adaptation levels and are not due to different spontaneous activity. Interneuronal response variability of the off-center-neurones was twice as large as that of the on-center-neurones. 5. Change from dark to light adaptation had only a small but significant influence on summation properties. The poststimulus discharge rates were higher during light adaptation and the summating area was slightly larger (about 5–10%). 6. A comparative curve fitting procedure for three suitable mathematical functions revealed that the hyperbola describes the neuronal summation curves better than a logarithmic or power function. The latter do not fit the constant asymptotic part of the curve. The significance of the results for a dynamic interpretation of the organisation of visual receptive fields is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234924
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    A macroscopic analysis of composites containing layered spherical inclusions (1969)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 9 (1969), S. 90-99 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: This investigation considers a hypothetical three-phase ordered composite to permit the design of a new material both stiffer and tougher than the matrix phase alone. The required elastic solution is greatly simplified and was based on a single layered inclusion in an otherwise infinite matrix under uniaxial tension. The solution presented is exact and generalized to accommodate any number of concentric layers of different thickness and composition.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760090204
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    A model for polymer fatigue (1969)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 9 (1969), S. 121-130 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Attempts to use low-cycle fatigue techniques derived from the work of Coffin and Manson to predict the fatigue performance of six diverse structural plastics are discussed. Through an analysis of dynamic property and thermal behavior studies of polymer samples in reversed-tension fatigue, an improved model for the polymer fatigue process has been proposed. Laboratory test data are presented illustrating the relationship between the various models.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760090208
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    The interfacial stresses in particulate composite systems (1969)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 9 (1969), S. 100-104 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: It is postulated that property gradients exist at the interface forming an “interphase” between the insert and the matrix. Such gradients might be caused by partial solubility and diffusivity of the two phases comprising a composite. For simplicity, the “interphase” is replaced by a shell exhibiting averaged properties (Eshell = 1/2 Einsert + 1/2 Ematrix, etc.). An exact linear elastic solution was employed to evaluate stress fields throughout all regions. The possible effect of the “interphase” and its thickness on several physical properties of the composite are evaluated in terms of the particular stress fields.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760090205
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    Masthead (1969)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 9 (1969) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760090301
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  • 56
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    Dynamic mechanical properties of polymer melts: The dependence of viscoelastic properties on molecular weight distribution (1969)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 9 (1969), S. 159-163 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: An investigation of the dynamic mechanical properties of several molten polymers was performed using the Maxwell Orthogonal Rheometer. Relaxation spectra derived from experimental data for the terminal region of viscoelastic response indicate that as molecular weight distribution broadens, terminal relaxation phenomena associated with molecular disentanglement and translation extend over a corresponding wider frequency range. The same data indicate that a true maximum relaxation time beyond which no elastic response is observed exists for the materials studied. Moreover, the maximum relaxation time corresponds to the reciprocal of the frequency where the dynamic viscosity deviates from its zero-shear value. Thus an estimate of the time necessary for complete elastic recovery in polymer melts is readily obtained experimentally.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760090303
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    Interpretation of the tensile creep response of an ABS polymer (1969)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 9 (1969), S. 190-196 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Tensile creep measurements were carried out on a commercial ABS polymer over a temperature range from 40 to 100°C at stress levels from 0.6 to 1.8 × 108 dynes/cm2. Experiments were conducted in a prototype of an apparatus designed to be compatible with digital acquisition systems. Analysis of the data indicated that application of the time-temperature super-position principle was of limited value due to the use of test temperatures near and below the effective glass transition temperature of the acrylonitrile-styrene component of the polymer. A strong stress dependence of the compliance was observed, even at relatively short times after loading. This was analyzed in terms of a model in which the height of the potential energy barrier to motion of the molecular flow unit is lowered by the application of stress. Analysis of the temperature dependence of the compliance at low stress levels indicated that the effective Tg of the acrylonitrile-styrene phase is about 85°C. The temperature dependence of the magnitude of the activation energy is considered as is the stress dependence of the glass transition temperature. Implications of short-time response in creep with regard to response under impact loading are pointed out. Practical application of results to the prediction of dimensional stability of molded parts is discussed as well as the limitations involved in extrapolation of experimental data to long times and high stress levels.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760090307
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    Fine structures and fracture processes in plastic/rubber two -phase polymer systems. I. Observation of fine structures under the electron microscope (1969)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 9 (1969), S. 197-205 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Fine structures of several plastic/rubber two -phase polymer systems were studied by means of direct observations of ultrathin sections under the electron microscope using osmium tetroxide staining and a hardening procedure developed recently by Kato. Samples used are several types of both ABS polymers and high -impact polystyrenes, and several PVC/rubber blends and the results were discussed in relation to their dynamic viscoelastic properties. It is suggested that these studies may fruitfully be extended to clarify the structure -to property relationships by use of this method.
    Additional Material: 19 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760090308
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    Thermomechanical studies of polymer deformation part I: A New deformation calorimeter (1969)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 9 (1969), S. 250-254 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The purpose of this paper is to describe a new deformation calorimeter, which is based on differential thermometry and uses a flowing gas stream as a heat transfer medium which allows it to operate under near-isothermal conditions. Also presented are some preliminary test measurements with a crosslinked polyurethane elastomer and crystalline polybutene-1.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760090404
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    The effect of antiplasticization on secondary loss transitions and permeability of polymers (1969)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 9 (1969), S. 277-281 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Antiplasticizers are considered to be diluents which when added to polymers result in mechanical property behavior opposite to that of plasticization. The addition of antiplasticizers to certain polymers such as Bisphenol A polycarbonate, polysulfone, and polyvinyl chloride results in the elimination of the secondary loss transitions of these polymers. As a drop in modulus accompanies these transitions, their elimination results in higher tensile strength and tensile modulus. As secondary transitions are commonly associated with ductility and impact strength, their elimination also results in the observed embrittlement characteristics. The addition of anti-plasticizers to polymers also restricts the diffusion of penetrants resulting from the decrease of molecular flexibility in the polymer matrix.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760090407
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    Masthead (1969)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 9 (1969) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760090501
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    Meaning and measurement of crystallinity in polymers: A Review (1969)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 9 (1969), S. 331-338 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A useful concept in polymer science is the degree of crystallinity - the fraction of the polymer that exists in a relatively ordered state. Methods of determination of the degree of crystallinity using density, infrared, thermal, N.M.R. and X-ray measurements are examined in light of modern notions of the structure of semi-crystalline polymers.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/pen.760090504
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    Shear modification of polythene (1969)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 9 (1969), S. 405-414 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The changes occurring when polythene melts are subjected to shear, have been investigated using a rotating bob fitted into a ram extruder. In addition to chain scission, low density polythene exhibits reversible changes in mechanical and viscoelastic properties. The magnitude of the changes is controlled by total shear strain, and is related to molecular weight and long chain branching. The mechanism appears to be one of reversible disentanglement operating mainly on the large highly branched molecules. The work is relevant to various extrusion processes and to other long-branched polymers.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760090606
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    Fatigue behavior of glass-fiber fortified thermoplasticsPart of a thesis submitted to Illinois Institute of Technology in partial fulfillment of the requirements for the MS degree. (1969)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 9 (1969), S. 434-444 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: This investigation deals with the fatigue behavior of a group of thermoplastics fortified with discontinuous glass fibers dispersed by an injection molding process. The thermoplastics included nylon, polystyrene and polyethylene reinforced with short (1/8 in.) and long (1/2 in.) glass fibers.Several aspects of the fatigue behavior are included in the study. First, classical S-N curves were generated under fluctuating tension with R = 0.05 to show the loss of strength due to cyclic load application. Next, the extent of progressive fatigue damage was established by measuring the residual strength after cyclic loading. Finally, hypotheses pertaining to the fatigue mechanisms operative in all four materials were made based on microscopic examinations of sections removed from fatiguedamaged specimens.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760090610
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    Strength -Composition relationships of random short glass fiber -thermoplastics compositesThis paper was presented at the 26th Annual Technical Conference of The Society of Plastics Engineers, May, 1968. (1969)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 9 (1969), S. 213-224 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Twelve polymers and copolymers reinforced with random short glass fibers are used for the study of the strength -composition relationship. Six of these reinforced systems are new and have not been reported elsewhere. The effect of fiber volume fraction on tensile and flexural strengths is related to the Kelly and Tyson equation. For each composition the strengthening factor, F, is calculated and discussed with respect to the structure of the polymer. One factor pertaining to the actual performance of fiber glass, fiber efficiency, K, has been extrapolated for the fiber glass used for this study. The effects of fibers on toughness and the Izod notched impact strength are discussed. It is the impact strength ratio and not the toughness which is used to describe the net result of reinforcement.The deviations between the wet and the dry strengths are used to illustrate the effect of the fiber -matrix interfacial bond. A new parameter, Δθ, is introduced to describe the effect of structure on the fiber -matrix interface. The effect of water at the fiber -matrix interface is further demonstrated through the determination of dielectric constant and dissipation factor of the composite before and after water immersion. The rule of mixtures was found to apply to dry electrical properties of composites.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760090310
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    Effects of shear stress on the crystallization of linear polyethylene and polybutene-1 (1969)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 9 (1969), S. 225-241 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The effects of shear stress on the crystallization kinetics and morphology of linear polyethylene and polybutene-1 were studied with the aid of a specially designed apparatus. With this equipment, it was possible to heat a thin polymer sample between glass slides to a melt temperature, quench the sample to a crystallization temperature, and then deform the sample in shear by applying a constant load to one of the glass slides. During the deformation, the crystallization process was observed and photographed under a polarizing microscope. Also, the displacement of the glass slide was simultaneously recorded which made possible a determination of the shear strain as a function of time.The results demonstrate that two phenomena may occur in the initially supercooled polymer samples in response to the applied shear stress. In one case, the sample deformed until it fractured, generally exhibiting no evidene of crystallization; in the other, the sample deformed until an inflection point was reached after which the sample became rigid. This latter phenomenon was attributed to crystallization.At low shear stresses, the inflection point was associated with the growth of spherulites which simply became large enough to bridge the glass slides and prevent further deformation of the sample. This generally occurred prior to the completion of the radial growth of the lamellae.At high shear stresses, however, no evidence of crystallization was seen in the microscope until the inflection point was reached. At this point, birefringence was observed in the sample. The resulting structure generally could not be resolved in the microscope, thereby indicating very profuse nucleation.The results obtained clearly demonstrate that the application of a sufficiently high shear stress to an initially supercooled melt has a substantial effect on the rates of crystallization of both polyethylene and polybutene-1. This was shown most dramatically at temperatures close to the melting point, e.g., both polyethylene at 130°C and polybutene-1 at 113°C, which require over 104 sec to crystallize under quiescent conditions, crystallized at approximately 0.05 seconds.The application of a shear stress to a polymer melt is envisaged as resulting in molecular orientation. In accord with the theories of Flory, and Krigbaum and Roe, the associated decrease in entropy of the melt may be considered to increase the supercooling. Under high stresses at which large increases in supercooling result, crystallization occurs more rapidy at the high temperatures and with polymers of lower molecular weight. At low shear stresses, the influence of temperature and molecular weight on the crystallization kinetics is essentially the same as that obseved under quiescent conditions.Observations through the microscope have shown that the application of a shear stress to a polymer melt leads to large increases in the number of crystalline structures formed and to the formation of oriented morphologies. This latter phenomenon arises due to nucleation lines formed by impurities and spherulites in the deforming melt. The impurities and spherulites apparently cause a disturbance which is thought to result in a local increase in stress of the melt and, hence, a local increase in supercooling. Lamellae then nucleate on these lines and grow out radially.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760090402
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  • 67
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    Fine structures and fracture processes in plastic/rubber two -phase polymer systems. II. Observation of crazing behaviors under the electron microscope (1969)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 9 (1969), S. 206-212 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Detailed crazing behavior in several plastic/rubber twophase polymer systems was studied by means of direct observation of ultrathin sections under the electron microscope by employing osmium tetroxide staining and hardening procedure. Samples used are ABS polymer, high -impact polystyrene and several PVC/rubber blends. All of the systems investigated showed evidence of stress -crazing when under flexural stress. Relationships between the dispersed rubber particles and the crazing behaviors were studied, and the role of rubber particles in the toughening mechanism of plastics was discussed based on these observations.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760090309
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  • 68
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    The effect of penetrant activity and temperature on the anomalous diffusion of hydrocarbons and solvent crazing in polystyrenePresented at the Symposium on “Time Dependent Properties of Plastic Materials” sponsored by Plastics Institute of America, Stevens Institute of Technology, Hoboken, New Jersey, Nov. 6, 1968. part I: Biaxially oriented polystyrene (1969)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 9 (1969), S. 242-249 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The effects of temperature and penetrant activity on the sorption kinetics and equilibria of a series of alkanes in glassy, biaxially oriented polystyrene were studied. Normal isomers of pentane, hexane, and heptane cause crazing of polystyrene film samples at high penetrant activities (〉 0.85). Crazing kinetics are identical to the kinetics of Case II transport. Transport of these normal hydrocarbons in glassy polystyrene in the temperature range 25 to 50°C is markedly non-Fickian; limiting Case II transport is observed at activities in exces of 0.6. Sorption appears to be controlled by highly activated relaxation processes including primary bond breakage at these high penetrant activities. Fickian diffusion behavior is approached, however, as penetrant activity is reduced. Sorption of the branched isomers of these compounds does not result in polymer microfailure. The sorption kinetics of the branched isomers, although time dependent, appear to be controlled primarily by thermally activated diffusion rather than large scale polymer relaxations which control Case II transport.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760090403
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  • 69
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    Masthead (1969)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 9 (1969) 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760090401
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  • 70
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    Thermodynamic and physical properties of crystals formed from dilute solutions (1969)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 9 (1969), S. 255-267 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Some of the thermodynamic and physical properties of crystals of linear polyethylene, formed from dilute solution are discussed. These properties include density, enthalpy of fusion, infrared absorption spectrum, selective oxidation and dynamic mechanical measurements. Despite the fact that electron microscopic examination reveals an apparent geometric regularity to these crystals, all these physical measurements yield a consistent interpretation in that they require about 15-20% of the chain units to be in a non-random conformation, and to form a disordered amorphous overlayer.Detailed studies of the experimentally observed relations between the crystallite thickness, crystallization temperature, and dissolution temperature (melting temperature in a dilute solution) are also presented. A thermodynamic analysis of the dissolution temperature-size relations, based on independently determined equilibrium solubility temperatures, indicates that the interfacial free-energy characteristic of the mature crystallites is significantly different from that involved in nucleation. The interfacial structures of the nucleus and the crystallites must, therefore, also be different. Size control by a nucleation process can be demonstrated from very general theoretical considerations. However, the detailed molecular structure characteristic of the nucleus cannot be specified solely from the fact that this process is size controlling.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760090405
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  • 71
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    Some physical organic chemistry of aging processes (1969)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 9 (1969), S. 282-285 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Work at Stanford Research Institute on the deterioration of polymers is based on the assumption that aging in the light is the most serious problem and that it has at least three components that must be separated if we are to understand the overall process. We have started by measuring the production of free radicals on the polymer when pairs of t-butoxy radicals are generated from thermal decomposition of di-t-butylperoxy oxalate (DBPO) in bulk atactic polypropylene at temperatures approximating service conditions, 35-50°C. Our preliminary experiments have brought out experimental difficulties and have raised more theoretical questions than they have answered. Nevertheless, they show that the efficiency of production of polymer radicals is low and sensitive to the mobilities of the polymer chains. They also suggest that two kinetically different oxidation processes, with different dependencies on rates of initiation and with different susceptibilities to inhibitors, are proceeding simultaneously. The implications of these findings for results of some previous work and for design of improved accelerated tests is considered.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760090408
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    On the characterization of nonlinear viscoelastic materialsPresented at the SPE Symposium on Design of Experiments and Data Analysis in Plastics Engineering, September 1968. (1969)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 9 (1969), S. 295-310 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Starting with specific constitutive equations, methods of evaluating material properties from experimental data are outlined and then illustrated for some polymeric materials; these equations have been derived from thermodynamic principles, and are very similar to the Boltzmann superposition integral form of linear theory. The experimental basis for two equations under uniaxial loading and the influence of environmental factors on the properties are first examined. It is then shown that creep and recovery data can be conveiently used to evaluate properties in one equation, while two-step relaxation data serve the same purpose for the second equation. Methods of reducing data to accomplish this characterization and to determine the accuracy of the theory are illustrated using existing data on nitrocellulose film, fiber-reinforced phenolic resin, and polyisobutylene. Finally, a set of three-dimensional constitutive equations is proposed which is consistent with nonlinear behavior of some metals and plastics, and which enables all properties to be evaluated from uniaxial creep and recovery data.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760090410
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  • 73
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    Brabender viscometry: I. Conversion of brabender curves to instron flow curves (1969)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 9 (1969), S. 360-364 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Equations have been derived to convert Brabender flow curves to Instron flow curves for practical application purposes. The technique involved is simple and has been described and discussed in detail. Nine pairs of Brabender and Instron flow curves of three different high polymers, each at three operating temperatures, have been found to fit each other quite well. The converted Brabender flow curves overlap a part of the Instron curves and extend the shear range toward the Newtonian flow region. An important consequence of this work is that the Brabender Plastograph can now be regarded as a formal viscometer while still functioning as a miniature of the Banbury mixers used in industry. More work is being done to take advantage of this consequence.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760090508
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  • 74
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    Combined tension-torsion creep experiments on polycarbonate in the nonlinear range (1969)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 9 (1969), S. 378-382 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Constant stress creep and recovery experiments were performed in the nonlinear range under combined tension and torsion on a tubular specimen of polycarbonate. Nonlinear viscoelasticity theory was employed to describe the test results. It was found that the first three orders of stress terms and a power function of time adequately described the experimental results. The modified superposition principle satisfactorily predicted the recovery following creep. Recovery was almost complete in several days following two hours of creep.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760090511
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  • 75
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    Physical optics of iridescent multilayered plastic films (1969)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 9 (1969), S. 400-404 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The physical optics of iridescent multilayered plastic films are analyzed theoretically relating the layer thickness, layer arrangement, and refractive index difference between layers to the reflection spectra for light at normal incidence. Very vivid iridescent and metallic-appearing films may be made by proper control of layer distribution.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760090605
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  • 76
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    The mechanical and other physical properties of polyelectrolyte salts in the solid stateContribution HPC 67-49 from the Monsanto/Washington University Association sponsored by the ONR and ARPA. (1969)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 9 (1969), S. 356-359 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Salts of polyacrylic acid can be fabricated in heated molds using mixed powders of polyacrylic acid and metal oxides. Because of the strong intermolecular forces in these polyelectrolyte salts, they have elastic moduli several times greater than the moduli of conventional plastics. They also have very low coefficients of expansion and high compression strengths. Composites containing metallic and inorganic fillers have also been made and their mechanical properties measured.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760090507
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  • 77
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    Electronic Resource
    New processability concepts for rigid vinyls (1969)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 9 (1969), S. 445-451 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The dynamic thermal stability of rigid PVC resin compositions as determined from Brabender torque rheometer tests has a linear relationship of stability time and torque from which a practical measure of processability at a fixed torque can be derived. The stability time at 1500 m-g torque, t1500, has been used to characterize differences between PVC homopolymer and copolymer resins in tin, calcium-zinc, lead, and bariumcadmium stabilizer systems. In every case, the vinyl chloride-propylene copolymers are unique in giving substantial process-ability advantages.The logarithm of stability time at a fixed torque, t1500, is a linear function of intrinsic viscosity, [η], for PVC homopolymers, giving a single line function corresponding to the expression log t1500 = A + B [η]. The constants, A and B, vary with each of the four stabilizer systems, and are related to the effectiveness of the particular formulations used.The ratio of t1500 for copolymers to the basic t1500 value for PVC homopolymers at the same intrinsic viscosity (molecular weight) is a practical measure of relative processability, trel, which is characteristic of PVC resin types and independent of stabilizer systems.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760090611
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  • 78
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    Reversible crosslinking in cellulose. I. Determination of mercaptan and disulfide in modified cotton (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 1845-1858 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Mercaptan and disulfide contents of modified cotton fabrics could be determined by application of Leach's polarographic method for wool, with minor modification.It was found that mercaptocellulose prepared by the reaction of tosyl cellulose and potassium thiolacetate followed by alkaline hydrolysis contained considerable amounts of disulfided in addition to mercaptain. Iodometric titration of mercaptocellulose gave a higher value of mercaptan than that obtained by the polarographic method. The mercaptan and disulfide contents and methylene blue uptake of the iodine-treated samples indicate that some of the mercaptan groups further undergo oxidation to acidic groups as a result of the iodine treatment.The spatial effect in the oxidation of mercapto groups in modified cotton is briefly discussed.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070130904
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    Urethanes. I. Organometallic catalysis of the reaction of alcohols with isocyanatesPresented in part at the First Northeast Regional Meeting of the American Chemical Society, Boston, October 1968. (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 1929-1936 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The catalysis of the reaction of n-butyl alcohol with isocyanates, using organometallic derivatives of lead, tin, and mercury, has been investigated. The rate of the reaction was measured by following the disappearance of the isocyanate absorption in the infrared. Phenyl, n-butyl, and cyclohexyl isocyanate were chosen to represent typical aromatic primary and secondary aliphatic isocyanates. Within the same series of catalysts, RnMOAc, the catalytic effect decreases in the order RHg 〉 R3Sn 〉 R3Pb; and in all cases R = aryl 〉 R = alkyl. The electronic effects of substituents on the aryl moiety are not pronounced. Changes in X of RnMX greatly affect the catalytic activity. The mechanism of organometallic catalysis of the alcohol-isocyanate reaction occurs via a template-type mechanism whereby the catalyst acts to complex both reactants in a catalyst phase allowing the reaction to occur with greater facility.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070130912
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  • 80
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    Radical polymerization of N-vinylcaprolactam in homogeneous solution. II (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 1-7 
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    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The polymerization of N-vinylcaprolactam in toluene, dioxane, chlorobenzene, dimethylformamide, and ethylene carbonate with various peroxides, perbenzoates and azobisisobutyronitrile as initiators at 60-80°C, was studied. Under these conditions azobisisobutyronitrile and tert-butyl perbenzoate have satisfactory activity as initiators. Under these conditions N-vinylcaprolactam polymerization in homogeneous solution is first order towards the monomer and 0.5 order towards the initiators.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070130101
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  • 81
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    Photo-oxidation of phenoxy resin (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 9-15 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A study has been made of the photolysis and photo-oxidation of phenoxy resin. Photolysis results in the evolution of hydrogen, methane, ethane, propene, propane, toluene, and the oxides of carbon. Also observed are increased yellowing, a rapid rise in gel content, and a decrease in intrinsic viscosity and elongation. Photo-oxidation causes similar changes, but produces oxidized chain fragments, more gel, and less yellowing as well as broad absorptions in the hydroxyl and carbonyl regions of the infrared spectrum. A free-radical mechanism is proposed in which both chain scission and crosslinking occur.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070130102
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    Apparent anomalous thermal behavior of polymers undergoing a glass transition (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 2069-2072 
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    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Glass transitions in certain polymer samples were detected as a step change in a DTA trace in the exothermic sense. This anomaly is explained as a manifestation of the volume relaxation shown to occur at the glass transition in internally strained samples.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070131004
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  • 83
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    Graft copolymerization of styrene with carbon black-alkali metal complex (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 2057-2068 
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    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: It was found that an ion radical complex is formed by the reaction of carbon black with an alkali metal (Li, Na, K) in tetrahydrofuran. The graft copolymerization of styrene with carbon black was carried out using the ion radical complexes as initiator, and free polystyrene and carbon black-polystyrene graft copolymer were obtained. The identification of the graft copolymer with carbon black was carried out by fractionation and thermal degradation. The initiation activity of the alkali metals increased in the order Li 〈 Na 〈 K. The effect of the particle size of the carbon black on the graft copolymerization was studied.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070131003
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    The continuum interpretation for fracture and adhesionBased upon a lecture delivered at the Wayne State University, Polymer Conference Series, Detroit, Michigan, May 14, 1968. (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 29-40 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: From the viewpoint of continuum mechanics, and particularly the energy concept of fracture, adhesive and cohesive failures are similar. The essential difference involves the interpretation of the energy required to create new (adhesive or cohesive) surface area. A simple pressurized disk test is described for measuring the adhesive value for a bonded elastomer, and an application to a debonding problem in engineering design is given.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070130105
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  • 85
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    Swelling of cotton in alkalis and acids (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 41-54 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A study of the swelling of Acala 4-42 cotton in aqueous alkalis and acids has been carried out. The degree of swelling of the cotton in the reagents has been indicated by measurement of the variations in width of the cotton at its widest point. The nature of the swelling process whether interfibrillar or intrafibrillar has been deduced from microscopical and x-ray evidence. It has been shown that a similarity of shape of the swelling curves, i.e., an equal degree of swelling in the same or other reagents, does not imply the same mechanism of swelling. The results are more readily explained in terms of the crystalline-fibril theory than by the fringe-micellar theory, especially when high degrees of swelling have been achieved.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070130106
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  • 86
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    Electronic Resource
    High-temperature mechanical behavior of PVC: A comparison of suspension- and emulsion-prepared polymers (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 55-67 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: We have investigated the high temperature mechanical behavior of several unplasticized emulsion- and suspension-prepared whole polymers, and carried out molecular weight, molecular weight distribution, and branching characterization studies on these same materials. It is concluded that the easier workability of the emulsion product is probably due to the absence of a considerable amount of high molecular weight polymer in these as compared to suspension-prepared polymers of equal average molecular weight as reflected by intrinsic viscosity determinations of Fikentscher K values.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070130107
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  • 87
    Electronic Resource
    Electronic Resource
    Calcium stearate-stearic acid as lubricants for rigid poly(vinyl chloride) (PVC). Capillary rheometer measurements and extrusion properties (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 69-80 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Capillary rheometer measurements show that stearic acid can be characterized as a normal lubricant. If the content of stearic acid is increased in rigid PVC formulations, the melt viscosity will decrease. This leads to a corresponding increase of shear rate and volumetric flow rate. The influence of calcium stearate is opposite to the normal characteristic of a lubricant. Increasing amounts of calcium stearate lead to an increased melt viscosity and a decreased shear rate and volumetric flow rate. In the extrusion of rigid PVC, the apparent “lubricating” effect of calcium stearate is probably due to the increased friction with resulting heat evolution and higher mass temperature, leading to a decreased viscosity of the plastic melt. This is in agreement with the results of the extrusion experiments. Both mass temperature and power consumption decrease when stearic acid is added and increase when calcium stearate is added to the formulation.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070130108
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  • 88
    Electronic Resource
    Electronic Resource
    Failure mechanisms in peeling of pressure-sensitive adhesive tape (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 2193-2207 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Studies on the peel behavior of pressure-sensitive tape comprising a polyester backing and polyacrylate adhesive have shown that, in peeling from a plane glass surface, three fundamentally different modes of peeling may be distinguished, depending upon the rate of pulling. At low rates, deformation by flow of the adhesive appears to determine the peel behavior and the peel force is strongly rate dependent. At high rates, little or no viscous deformation of the adhesive occurs and the peel force is independent of rate. At intermediate pulling rates, cyclical instability of made of failure involving alternate storage and dissipation of elastic energy in the backing, results in the phenomenon of “slip-stick” peeling, in which failure is jerky and regular. Results have been obtained which show how the pulling rates at which transitions from one mode of peel to another occur, and the peel force values for a given type of failure, depend upon such factors as molecular weight of adhesive, thickness of backing film, and angle of peeling.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070131014
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  • 89
    Electronic Resource
    Electronic Resource
    Photocrosslinking of stilbene-modified polymers (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 2247-2255 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The reactions of trans-2,5-dimethoxy-4′-aminostilbene with poly(maleic anhydride-co-methylvinyl ether) and trans-2,5-dimethoxy-4′-isocyanatostilbene with poly(oxy-1,4-phenyleneisopropylidene:1,4-phenyleneoxy-2-hydroxytrimethylene) yield polymeric systems which undergo rapid crosslinking upon short exposure to ultraviolet light. The extent of photocrosslinking as a function of exposure time was determined by the decrease of the trans-stilbene ultraviolet absorption at 350 nm.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070131018
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  • 90
    Electronic Resource
    Electronic Resource
    Reactions of halogenated 1,2-epoxypropanes and diethylaminoethyl cottonPresented in part before the Division of Cellulose, Wood, and Fiber Chemistry at the 154th National Meeting of the American Chemical Society, Chicago, Illinois, September 1967. (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 81-92 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Diethylaminoethyl (DEAE)-cotton has been reacted with epichlorohydrin (1,2-epoxy-3-chloropropane) neat, in alcoholic solvents, and in aprotic solvents at temperatures ranging from 25 to 95°C. Fabric properties and electron micrographs of fibers removed from these chemically treated DEAE cottons have been compared with those obtained when DEAE-cottons were treated under similar conditions with other halogenated 1,2-epoxypropanes, and with 1,2-epoxy-4,4,4-trichlorobutane. For comparative purposes, epichlorohydrin was reacted with an aminized cotton containing primary amine groups, with cotton containing quarternary ammonium groups, and with DEAE-cottons in which the tertiary amine groups had been quaternized. For reaction at 95°C with net epichlorohydrin, greatest increase in conditioned wrinkle recovery was observed with DEAE-cottons. Only with DEAE-cottons were the add-ons and recovery angles imparted by epichlorohydrin affected by the anion associated with the amine groups. None of the halogenated 1,2-epoxypropanes reacted with unmodified cotton in the absence of a basic catalyst. Those that reacted with unmodified cotton in the presence of an external base catalyst did not improve conditioned recovery angles. The mono-, di-, and trichloro-1,2-epoxypropanes all increased the conditioned and wet wrinkle recovery of DEAE-cotton when reacted neat at 95°C. The type of oxirane ring opening of epoxypropanes was shown to be influenced by the degree of chlorination of the carbon alpha to the ring. Both primary amine groups and quaternary amine groups catalyzed the epichlorohydrin-cellulose reaction. Dilution of epichlorohydrin with alcohols or decreasing reaction temperature lowered add-ons and improvements in wrinkle recovery properties. Use of aprotic solvents for the DEAE-cotton-epichlorohydrin reaction gave finished cotton fabrics having only high wet wrinkle recovery properties.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070130109
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  • 91
    Electronic Resource
    Electronic Resource
    The manganic hydroxide-hydrazine hydrate system as an initiator of vinyl polymerization (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 2333-2340 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The reaction of hydrazine hydrate with manganic hydroxide and its application to the solution polymerization of methyl methacrylate has been studied. The kinetic evidence suggests that the hydrazine and the monomer are both adsorbed on the surface of the manganic hydroxide sol and that the decomposition of the hydrazine and the polymerization of the methyl methacrylate follow zero-order kinetics. The rate of polymerization increases slowly with increasing temperature, the activation energy for the polymerization being 4.9 ± 0.2 kcal/mole.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070131109
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  • 92
    Electronic Resource
    Electronic Resource
    Properties of blends containing petroleum jelly and 4-methyl-pentene-1 (TPX-RT-D30) (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 2383-2395 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The properties of 4-methyl-pentene-1 polymer (TPX-RT-D30) were altered by blending petroleum jelly (P.J.) with the polymer. The polymer was blended with up to 40% by weight P. J. The plasticization of the polymer by the P. J. apparently allows high molecular weight fractions of the polymer to crystallize and influences the crystalline size and perfection. Tensile properties of the blends showed both a break and yield value in all ratios as compared to only a break value for the pure polymer. Breaking strength ranged from 4000 psi for the polymer to 1000 psi at 40% P. J. The samples had a “necking down” effect at 10% P. J. Modulus decreased from 1.8 × 104 (literature value 2.1 × 105) to 2.3 × 104 at 40% P. J. Brittle point values varied from above room temperature to 5°C at 40% P. J. The Vicat softening point ranged from 181°C for the polymer to 87°C at 40% P. J. Differential thermal analysis (Stone) showed a melting point depression from 235°C to 218°C at 40% P. J.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070131113
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  • 93
    Electronic Resource
    Electronic Resource
    Determination of the extent of reaction for the system carboxyl-terminated polybutadiene-epoxide beyond the gel point by infrared spectroscopy (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 2439-2445 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Curing reactions were investigated after the gel point, using infrared transmittance and reflection spectrophotometric techniques. In the system carboxyl-terminated polybutadiene (CTPB)/Epon X801 or Epotuf STF-6, catalyzed with Fe(III)-acetyl-acetonate (FeAA), at an equivalent ratio of carboxyl to epoxide groups, the final extent of reaction of COOH groups was found to be between 64% and 77% for eight CTPB samples. Increasing the ratio of epoxide to carboxyl groups (up to 1.6) resulted in an increase in the conversion, but the complete reaction of COOH groups could not be accomplished. The final extent of reaction also depends upon the functionality of the crosslinking agent. The lower the functionality of the epoxide, the higher the conversion of COOH groups. The use of chromium naphthenate as a catalyst for epoxide-COOH reactions gave higher conversions than FeAA. This result is related to side reactions catalyzed by the chromium naphthenate. The change in mechanical properties and the change in extent of reaction were followed simultaneously; it was found that no further development of mechanical properties occurred when the curing reaction between COOH and epoxide groups had ceased.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070131117
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  • 94
    Electronic Resource
    Electronic Resource
    Thermal conductivity, specific heat, and dynamic mechanical behavior of diglycidyl ether of bisphenol a cured with m-phenylenediamine (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 2411-2425 
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    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The thermal conductivity, specific heat, and dynamic mechanical behavior of an epoxide system have been investigated over a relatively wide temperature range. Effects of nonstoichiometric amine concentrations and postcure heat treatments were included in the study. The thermal conductivity behavior was found to be related to the extent of cure of the poxy system, but in general the results were typical of an amorphous polymer. Calorimetric determinations were used to study the curing reaction and the glasslike transition temperature for the various systems. Dynamic mechanical results were employed to delinearte the various internal relaxations of the cured materials and in some instances to permit correlation of relaxations with the thermal conductivity and the specific heat results. From comparison of present results to those of a previous paper, the activation energy for the relaxation process occurring near 270°K has been estimated to be 16 kcal/mole.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070131115
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  • 95
    Electronic Resource
    Electronic Resource
    X-ray studies on cellophane1 (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 2459-2468 
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    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: X-Ray diffractograms of cellophane showed a considerable variation in the intensity corresponding to the 101, 101, and 002 planes. Applications of generally accepted procedures for estimating crystalline content in cellulosic materials yields varying results for crystallimity in cellophane. It is concluded that such procedures are not applicable to cellophane used in this study.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070131119
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  • 96
    Electronic Resource
    Electronic Resource
    Effect of secondary polymer structure on the drag-reducing phenomenon (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 2499-2503 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070131122
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  • 97
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    Electronic Resource
    Voids as a source of haze in weathered poly(2,2,4,4-tetramethyl-1,3-cyclobutylene carbonate)Presented before the American Physical Society, Division of High Polymer Physics, Philadelphia, Pennsylvania, March 1969. (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 2483-2497 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Long-term weathering studies of the subject transparent thermoplastic polymer revealed that sheets extruded from pristine resine gradually became hazy. Electron microscopy of fracture surfaces showed that minute voids were created during outdoor exposure. By the application of the Mie light scattering theory, it was possible to calculate that the average void size was 4 × 103 Å and that the concentration of voids numbered about 106/mm3. Yet the total void volume of the poorest sample, which had a haze value of 26%, was less than 0.05%. The average void size decreased over a three-year period, but the concentration increased with exposure. A mechanism of void formation was formulated based on photo-induced moleculàr degradation. Chemical evidence suggests that molecular degradation occurs by complete unzippering of a molecule, resulting in the formation of carbon dioxide and 2,2,4-trimethylpentene-3-al. The aldehyde is believed to plasticize the polymer in the vicinity of a growing void and the carbon dioxide acts as a blowing agent, therby generating a void. Simultaneously, free radicals formed during molecular decomposition initiate further degradation of neighboring molecules. The propensity of this resin to haze can be effectively overcome by suitable cleanup and stabilization procedures.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070131121
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  • 98
    Electronic Resource
    Electronic Resource
    Comparaison des méthodes de fractionnement par chromatographie de perméation et par gradient d'elution pour la détermination des répartitions moléculaires des polypropylénes (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 205-213 
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    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Molecular weight distributions for polypropylene samples have been determined by a permeation fractionation method (GPC). Porous silica beads were used as a packing material for the columns. The set of columns allows a good separation of the polypropylene macromolecular chains in a range of molecular weights from 5000 to 1.5 × 106, and the thermal and mechanical stabilities of these beads are very good. The calibration has been carried out with fractions of polypropylene of narrow molecular weight distribution prepared by a large-scale column fractionation. The molecular weights M̄w and M̄n and the ratios M̄w/M̄n calculated from the GPC curves show, in general, good agreement with the ones calculated from the column fractionation curves. However, the M̄w/M̄n ratios are always highter in the case of GPC fractionation. This could be due to diffusion phenomena.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070130119
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  • 99
    Electronic Resource
    Electronic Resource
    Storage-stable epoxy B-stage resins (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 227-232 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: N-Substituted β-aminopropionhydrazides, RNHC2h4CONHNH2, were prepared by the Michael addition of primary amines to acrylic esters. The adducts were converted to the corresponding hydrazides. The aminohydrazides react readily with terminal epoxides at moderate temperatures yeilding B-stage resins of excellent storage stability. When powdered B-stage resins are sprayed on hot metal (150-230°C.), a smooth cross-linked coating is formed in less than 3 min. The coatings have unusually high elasticity, they pass the Olson button test. For best performance the amine used should have the primary amino group attached to either a primary carbon atom or directly to an aromatic nucleus. Aminohydrazides with the following R. Groups have been prepared: methyl, n-butyl, sec-butyl, tert-butyl, phenyl, cyclohexyl, benzyl, octyl, dodecyl, and octadecyl.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070130121
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  • 100
    Electronic Resource
    Electronic Resource
    Permeability to water of glow discharge-treated nitrocellulose (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 249-250 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070130124
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