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  • 1970-1974  (436)
  • 1965-1969
  • 1920-1924
  • 1973  (436)
  • Chemical Engineering  (356)
  • Ultrastructure  (80)
  • 1
    Electronic Resource
    Electronic Resource
    Electron microscopic visualization of proteoglycans and collagen in bovine costal cartilage (1973)
    Springer
    Calcified tissue international 13 (1973), S. 83-92 
    Details
    ISSN: 1432-0827
    Keywords: Proteoglycan ; Collagen ; Cartilage ; Electron Microscopy ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Description / Table of Contents: Résumé L'élimination de protéoglycans solubles de coupes de cartilage costal de boeuf, par extraction dans une solution de 4M d'hydrochlorure de guanidinium, permet de mettre en évidence des quantités abondantes de collagène dispersé et désagrégé dans la matrice. Les protéoglycanes, résistants à l'extraction, sont visibles sous forme de granules concentrés dans les régions périlacunaires. Les granulations plus importants des protéoglycanes semblent venir du chondrocyte. Dans la matrice, éloignée des chondrocytes, ces granules deviennent plus étroites. Un composant non granulaire “amorphe” masque les fibres de collagène, de telle sorte qu'elles sont difficilement visibles dans le cartilage intact.
    Abstract: Zusammenfassung Die löslichen Proteoglycane wurden mittels Extraktion in 4 M Guanidinhydrochlorid aus Rippenknorpelschnitten des Rindes entfernt. Dies erlaubte die Sichtbarmachung von großen Mengen von verstreuten und auseinandergerissenen Collagen in der Matrix. Die Protoglycane, welche sich nicht extrahieren lassen, erscheinen als kleine, in den perilacunären Regionen konzentrierte Körnchen. Die großen Proteoglycan-Körner scheinen in den Chondrocyten zu entstehen. Sobald sie sich in die Matrix, außerhalb der Chondrocyten, verlagern, werden die Körner kleiner. Ein nicht-granulärer, „amorpher” Bestandteil verhüllt die Collagenfasern, so daß diese im intakten Knorpel nicht deutlich gesehen werden können.
    Notes: Abstract Removal of the soluble proteoglycans from slices of bovine costal cartilage by extraction in 4 M guanidinium hydrochloride permitted the visualization of abundant amounts of dispersed and disaggregated collagen in the matrix. Proteoglycans which are resistant to extraction are seen as small granules which are concentrated in the perilacunar regions. Large proteoglycan granules appear to originate in the chondrocyte. As they come to occupy positions in the matrix distant from the chondrocyte, the granules become smaller. A non-granular, “amorphous” component masks the collagen fibers so that they cannot be readily seen in the intact cartilage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02015399
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  • 2
    Electronic Resource
    Electronic Resource
    Ultrastructural aspects of the preattached pig embryo: Cleavage and early blastocyst stages (1973)
    Springer
    Anatomy and embryology 143 (1973), S. 95-114 
    Details
    ISSN: 1432-0568
    Keywords: Cleavage stages ; Blastocyst ; Pig ; Nucleus ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrastructural observations of morphological changes in nuclei and cytoplasm of pig embryos during cleavage and early blastocyst stages are presented. Compact nuclear bodies (nucleosphaeridies) are demonstrable in the cleavage stages, and occasionally in the inner cell mass of blastocysts. The transformation of nucleosphaeridies leading to the formation of a peripheral network are usually found at the eight-cell stage. In morula, nucleoli make their first appearance as clearly distinguishable morphological entities. A marked disorganization of nuclear envelope is observed near to the cytoplasmic annulate lamellae (CAL) indicating a possible process of transformation of the former to the latter. During premorula stages cytoplasmic organelles (Golgi complex, endoplasmic reticulum, and CAL) are predominantly concentrated around the nucleus. CAL associated with fibrillogranular material similar to the material of the nucleoplasm occur in juxtanuclear positions. In the two-cell stage, degenerating paternal mitochondria are observed. In the morula the number of spherical mitochondria fell while that of elongated mitochondria increase. The trophoblast cells of the blastocyst stage contain cytoplasmic microfilaments which are closely associated with cell organelles, particularly the desmonsomes. Structurally changed mitochondria near the yolk globules and inclusion bodies of various morphology are found. A basal lamina is discernible parallel to the trophoblast layer facing the blastocoel. The observations are discussed in relation to physiological phenomena known to occur during embryogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00519913
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  • 3
    Electronic Resource
    Electronic Resource
    Uterine stromal morphology of the spayed, virgin rat when prepared with progesterone and oestrogen for implantation (1973)
    Springer
    Anatomy and embryology 141 (1973), S. 161-169 
    Details
    ISSN: 1432-0568
    Keywords: Rat ; Uterus ; Stroma ; Ultrastructure ; Sex steroids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of progesterone and oestrogen on the central uterine stroma has been examined in order to analyze what changes occur when the uterus is hormonally prepared for implantation. Both progesterone and oestrogen, when given separately, cause nucleolar enlargement and growth of the granular endoplasmic reticulum. However, after progesterone treatment the nuclei are large and spherical whereas they are spindle-shaped after oestrogen treatment. When oestrogen is administered to the progesterone-treated rat little change occurs in the stromal morphology. There is little morphological support to the view that oestrogen acts on the stroma to increase endometrial sensitivity. Further, progesterone seems to stimulate the synthesis of RNA and of cellular protein only in the stromal cell while oestrogen has a similar effect in all cell types of the uterus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00519883
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  • 4
    Electronic Resource
    Electronic Resource
    Licht- und elektronenmikroskopische Untersuchungen an den peritubulären Zellen des Schweinehodens während der postnatalen Entwicklung (1973)
    Springer
    Anatomy and embryology 143 (1973), S. 49-64 
    Details
    ISSN: 1432-0568
    Keywords: Testicular peritubular cells ; Boar ; Postnatal development ; Ultrastructure ; Contractility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Membrana propria der Hodentubuli des Schweines zeigt einen deutlichen Schichtenbau: Auf die Basalmembran des Tubulusepithels (a) folgen eine nicht-celluläre Lage mit Kollagenfibrillen (b), die von einer inneren (c) und einer äußeren (e) Basalmembran umhüllten peritubulären Zellen (d) und dann das intertubuläre lockere Bindegewebe (f). Die ausdifferenzierten peritubulären Zellen haben viele morphologische Merkmale mit glatten Muskelzellen gemeinsam. So besitzen sie Plasmalemmeinbuchtungen in Form pinocytotischer Bläschen sowie eine große Anzahl von Filamenten mit einem Durchmesser von 60–70 Å, welche über elektronendichte Strukturen an der Innenseite des Plasmalemms befestigt sind. Ein Golgi-Apparat, rauhes endoplasmatisches Reticulum, Mitochondrien und Mikrotubuli bevorzugen eine kernnahe Position. Im Gegensatz zu den Verhältnissen bei anderen Species sind viele charakteristische Eigenschaften der peritubulären Zellen schon vor der Pubertät ausgebildet. Die Filamente können bereits am 4. Tag als feines Netzwerk beobachtet werden, sie erfahren am 25. Tag eine starke Vermehrung und sind von nun an regelmäßig orientiert. Auch andere Befunde sprechen dafür, daß die peritubulären Zellen um den 25. Tag eine gesteigerte Aktivität entfalten. Die histochemisch nachgewiesenen Konzentrationen von alkalischer Phosphatase, Adenosintriphosphatase und Glucose-6-phosphatase erreichen zu diesem Zeitpunkt die hohen Werte, die auch für die weitere Entwicklungsphase und die ausdifferenzierten peritubulären Zellen typisch sind. Pinocytotische Bläschen erscheinen in größerer Anzahl ab dem 97. Tag. Mit dem 140. Tag sind die peritubulären Zellen morphologisch ausdiffrenziert.
    Notes: Summary The boundary tissue of the porcine testicular seminiferous tubule (membrana propria) exhibits a distinct stratification: the basement lamina of the tubular epithelium (a) is followed by a non-cellular layer with collagen fibrils (b), the peritubular cells (d) with an inner (c) and outer (e) basement lamina and finally the intertubular loose connective tissue (f). Fully developed peritubular cells have many morphological features in common with smooth muscle cells, for instance inpocketings of the plasmalemma (pinocytotic vesicles) and a great number of filaments measuring 60–70 Å in diameter. These filaments are fixed at the inner side of the plasmalemma by means of electron-dense structures. The Golgi apparatus, rough endoplasmic reticulum, mitochondria and microtubules prefer a juxtanuclear position. In contrast that is seen in other species the porcine peritubular cells develop many of their characteristic features before puberty. In samples of the 4th day a fine network of filaments is already visible within the cytoplasm. These filaments are strongly augmented at the 25th day, and from now on they are arranged in a regular fashion. Other findings, also, underline an increased activity of the peritubular cells around day 25. At that time the concentrations of histochemically demonstrated alkaline phosphatase, adenosine triphosphatase and glucose-6-phosphatase reach the high levels typical for the stages of further development and the fully differentiated cells. Pinocytotic vesicles appear in great numbers from day 97. At the 140th day the morphology of the porcine peritubular cell is completely developed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00519910
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  • 5
    Electronic Resource
    Electronic Resource
    The early development of the median thyroid gland of the mouse (1973)
    Springer
    Anatomy and embryology 139 (1973), S. 319-336 
    Details
    ISSN: 1432-0568
    Keywords: Fetal thyroid ; Microfilaments ; Lysosomes ; Acid phosphatase ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The mesobranchial area and the median thyroid anlage of embryonic albino mice were investigated from the somite stage 4 to 40 (81/2–10 days of gestation). In stage I (5–25 somites), there is an unequal growth and differentiation of the epithelium in the floor of the pharynx, whereby a mesobranchial area with a stratified or pseudostratified epithelium is formed. This area is distinct from the remaining pharyngeal epithelium, among other things by an apical microfilament system in the superficial epithelial cells. It is found just basal to a row of plump cytoplasmic protrusions, which extend into the lumen of the pharynx. In stage II (26–40 somites), the cranial part (median thyroid anlage) of the mesobranchial area thickens in relation to the caudal part and grows down into the underlying mesenchyme. The filament system is concentrated in the superficial cell layer of the median thyroid anlage at the beginning of stage II and disappears during downgrowth. In both stages, but most pronounced in stage II, there is a population of 0.1–5 μ intracellular bodies, which occasionally contain the remains of organelles. The larger bodies, which often contain the remains of nuclei, are usually found peripherally while the smaller ones are more evenly distributed. Acid phosphatase can often be demonstrated histochemically in small bodies, while larger bodies are usually without reaction. Cells with pycnotic nuclei and/or degenerated cytoplasmic components are regularly found. Acid phosphatase can also be demonstrated in Golgi complexes and surrounding vesicles. Basal to the epithelium, bodies are occasionally found which may possibly have been extruded from that tissue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00519971
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  • 6
    Electronic Resource
    Electronic Resource
    Electron microscopic study of the muscle changes in diabetic amyotrophy (1973)
    Springer
    Acta neuropathologica 24 (1973), S. 331-339 
    Details
    ISSN: 1432-0533
    Keywords: Diabetic Amyotrophy ; Muscle Biopsy ; Ultrastructure ; Type II Fibre Atrophy ; Partial Denervation ; Neurogenic Atrophy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Seven cases of diabetic amyotrophy were investigated by histochemistry and electron microscopy of biopsied muscles. Type II fibre atrophy of various grades was observed in the proximal atrophic muscles. Various changes of Z-band were observed in type II atrophic muscle fibres. In addition, mitochondrial changes, accumulation of glycogen, thickening of the capillary basement membrane and changes in the intramuscular nerves were also observed, both in the proximal and distal muscles. Some impaired motoneuron innervation of proximal muscles as well as distal muscles in a poorly controlled diabetic condition is suspected in “diabetic amyotrophy”.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00685588
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  • 7
    Electronic Resource
    Electronic Resource
    Ultrastructure of a sacrococcygeal chordoma (1973)
    Springer
    Acta neuropathologica 25 (1973), S. 27-35 
    Details
    ISSN: 1432-0533
    Keywords: Ultrastructure ; Chordoma ; Sacrococcygeal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of a sacrococcygeal chordoma is presented. The cells vary in their size and electron density but are thought to have a common origin. The nuclei presented prominent nucleoli and intranuclear bodies. Centrioles were seen in some of the cells. The rough endoplasmic reticulum was prominent and in most cells was very distended and corresponded to the intracellular vacuoles of light microscopy. The contents of the rough endoplasmic reticulum and the abundant extracellular substance were similar.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00686855
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  • 8
    Electronic Resource
    Electronic Resource
    Ultrastructural analysis of phospholipase a induced changes in membranes of synaptic regions in rat motor cortex (1973)
    Springer
    Experimental brain research 16 (1973), S. 400-409 
    Details
    ISSN: 1432-1106
    Keywords: Ultrastructure ; Synapses ; Brain cortex ; Phospholipase A ; Membranes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of purified Naja nigricollis phospholipase A on slices from motor cortex from rat brain was analysed at an ultrastructural level. Samples stabilized directly with glutaraldehyde were compared with samples incubated in buffer with or without enzyme. Plasma membranes of nerve terminals, synaptic contact regions and synaptic vesicles were the main parameters studied. As judged by the electron microscopic technique the synaptic areas show a high resistance to the enzyme treatment. The intercellular space of the synaptic cleft seems unaltered. At the highest concentrations of the enzyme an increased density is noticed at the presynaptic part of the membrane. The extracellular space widens and nerve terminals and mitochondria become distended with increasing enzyme concentrations. The membranes all through the tissue appear ruptured to small pieces and at the highest enzyme concentrations used, altered in their structural organization. Quantitative analysis shows that the number of synaptic vesicles per unit surface area decreases, while ruptures of the plasma membranes of nerve terminals increase in number with increasing enzyme concentrations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233431
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  • 9
    Electronic Resource
    Electronic Resource
    Ultrastructure of herpes simplex virus infection of the nervous system of mice (1973)
    Springer
    Acta neuropathologica 26 (1973), S. 285-299 
    Details
    ISSN: 1432-0533
    Keywords: Herpes simplex Virus ; Ultrastructure ; Viral Infection ; Virus-Host Interaction ; Nervous System
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The nervous system and small intestine of mice infected with herpes simplex virus were examined by electron microscopy from the viewpoint of virus-host interaction. The host cells examined included the neuron, astrocyte, oligodendrocyte, and Schwann cell. The susceptibility of the latter was not less than that of the neuron. The endothelial cell, perineural fibrocyte and smooth muscle cell were also host cells. Replication of herpes virus in the nervous system was proven to be identical to that occurringin vitro; initial reproduction of nucleocapsids in the nucleus and subsequent maturation at the nuclear membrane with envelope formation, followed by discharge into the cytoplasmic reticular cavities and finally release from the host cell. Inconsistency in the distribution of virus particles and viral antigen was chiefly concerned with the host cell nucleus and the glial cytoplasm. Herpes virions, though few, were identified in the axons of peripheral nerves, and in the periaxonal space of myelinated fibres in the brain and the nerve ganglia. Virions were present in tiny vesicles in the perikarya or as naked particles. In the distal parts of peripheral nerve, there was marked dissociation in the amount of virions between Schwann cells and the axon. The significance of the endoneural space and the axon in the neural speread of infection is discussed briefly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00688077
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  • 10
    Electronic Resource
    Electronic Resource
    The ultrastructural arrangement of thrombosthenin in glycerol extracted thrombocytes (1973)
    Springer
    Cell & tissue research 138 (1973), S. 557-567 
    Details
    ISSN: 1432-0878
    Keywords: Thrombocytes ; Thrombosthenin ; ATP ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of glycerol extracted thrombocyte models was studied before and after incubation with ATP and under the influence of Salyrgan as inhibitor of contraction. The contractile system of the thrombocytes—thrombosthenin—consists of a spatial network of 50 Å wide thrombosthenin A and 100–120 Å wide thrombosthenin M filaments. At rest, the contractile system is arranged in a marginal zone. The ATP-induced contraction led to a concentric condensation of the network which resulted in a central cluster of cell organelles and at a later stage, disruption of the plasma membrane and release of the thrombocyte granules. All these changes which also occur during the formation of the hemostatic plug in vivo are therefore attributed to the reaction of the contractile protein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00572296
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  • 11
    Electronic Resource
    Electronic Resource
    Corticotrophic cells in the rostral zone of the pars intermedia and in the adjacent neurohypophysis of the rat and mouse (1973)
    Springer
    Cell & tissue research 136 (1973), S. 97-110 
    Details
    ISSN: 1432-0878
    Keywords: Hypophysis ; Mouse, rat ; Pars intermedia, rostral zone ; Corticotrophic cells ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the mouse, the rostral zone of the pars intermedia is almost exclusively composed of typical corticotrophic cells. They are located around and even within the neural stalk, at the level of transition between stalk and neural lobe. In the rat, the corticotrophic cells of the rostral zone are found in scattered islets among the MSH producing cells, and also in the neural lobe. In both the rat and mouse, these cells are in direct contact with various types of nerve terminals. Synaptoid contacts with aminergic and neurosecretory nerve fibers are observed. Furthermore they are also closely related to the hypophysial portal vessels. Following adrenalectomy, the cells located in the neurohypophysis always react more intensely than tose in the rostral zone. The functional significance of these corticotrophic cells which are subject to both humoral and neural regulation remains as yet hypothetical. Their participation in neurogenic stress response seems probable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307682
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  • 12
    Electronic Resource
    Electronic Resource
    Quantitative data on the fine structural organization of the palisade zone of the median eminence (1973)
    Springer
    Cell & tissue research 136 (1973), S. 111-120 
    Details
    ISSN: 1432-0878
    Keywords: Median eminence ; Rat ; Granular vesicles ; Ultrastructure ; Quantitative evaluation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In order to characterize different sub-zones in the palisade zone of the rat median eminence, quantitative ultrastructural parameters were applied to brains fixed in aldehyde-osmium tetroxide. The palisade zone has been subdivided in 4 successive sub-zones. Increasing numbers of granular vesicles (GV), especially those smaller than 110 nm, are observed from dorsal to ventral sub-zones. There also are more GV per unit area of nervous tissue in the perivascular than in the more dorsal sub-zones. The individual nerve profiles exhibit a larger size in the perivascular layer than in the more dorsal areas, whereas the number and size of nerve profiles devoid of vesicles diminish from dorsal to ventral. As a consequence more GV occur in the perivascular nerve profiles. In the GV containing nerve profiles the concentration of GV is, however, constant in the different sub-zones. A fluctuating size of the preterminal and terminal parts of the nerve fibres is suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307683
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  • 13
    Electronic Resource
    Electronic Resource
    Studies on the fine structure of the protozoan Cyclidium, with special reference to the mitochondria, pellicle and surface-associated bacteria (1973)
    Springer
    Cell & tissue research 139 (1973), S. 303-310 
    Details
    ISSN: 1432-0878
    Keywords: Protozoa ; Bacteria ; Association ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of Cyclidium, including the cilia, kinetosomes, pellicle, microtubules and kinetodesmal fibers is similar to that recorded for other ciliates. Of special interest is the attachment of rod-shaped bacteria within the longitudinally directed shallow surface folds of the protozoan. Both the bacteria and the surface of Cyclidium seem to possess an outer coating of a sticky substance which upon contact holds the bacteria to the protozoan. The bacteria appear to be attached by only a relatively small area of their surfaces. A dense substance appears within the alveolus of the pellicle at the regions of the attachment of the bacteria. The association of the organisms is probably a temporary one, and it is unknown whether either organism is benefited or harmed by the association. The position of the mitochondria in Cyclidium is unusual in that they all lie flattened against the inner membrane of the pellicle, usually in a position directly opposite to that of the attachment of the bacteria to the surface, thus being separated from the bacteria by only the outer cell membrane and the pellicle. Whether or not this close topographical relationship is of significance is unknown.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00306587
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  • 14
    Electronic Resource
    Electronic Resource
    The effect of salinity acclimation on the ultrastructure of the gills of Gammarus oceanicus (Segerstråle, 1947) (Crustacea: Amphipoda) (1973)
    Springer
    Cell & tissue research 139 (1973), S. 311-318 
    Details
    ISSN: 1432-0878
    Keywords: Gill ; Gammarus oceanicus ; Salinity acclimation ; Ultrastructure ; Mitochondria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Acclimation to low salinity induces changes in the ultrastructure of the gill cells of the marine euryhaline amphipod, Gammarus oceanicus. The gills are composed of a single cell type. In 100% artificial sea water, these cells contain moderate numbers of mitochondria which are randomly distributed in the cytoplasm. The plasma membrane is extensively invaginated at the apical, lateral, and basal surfaces. Acclimation to 20% artificial sea water induces a further invagination at the apical cell membrane to form an elaborate apical labyrinth. The extracellular spaces between the folds in the basal cell membrane dilate to 1500 Å or more. Mitochondria are more abundant and in many cells they undergo a change in conformation. The mitochondria are crowded into thin leaflets of cytoplasm between the dilated basal invaginations or into the narrow space between apical and basal cell membranes. Consequently, they lie in close contact with the plasma membrane over much of their surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00306588
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  • 15
    Electronic Resource
    Electronic Resource
    Zur Feinstruktur des dorsalen Riesenfasersystems im Bauchmark des Regenwurms (1973)
    Springer
    Cell & tissue research 139 (1973), S. 351-368 
    Details
    ISSN: 1432-0878
    Keywords: Lateral giant cells ; Dorsal giant fibres ; Earthworm, Lumbricus terrestris L. ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die Feinstruktur der segmental angeordneten Somata der dorsalen Riesenfasern im Bauchmark des Regenwurms Lumbricus terrestris L. (Günther, 1969) wird beschrieben und mit der Struktur anderer Neuronen von Vertebraten und Evertebraten verglichen. Die paarigen lateralen Riesenzellen (LRZ) sind im Gegensatz zu der unpaaren medianen Riesenzelle (MRZ) häufig multipolare Neuronen, die bis zu vier Faserfortsätze aufweisen können. Das perikaryale Cytoplasma zeigt helle und dunkle Areale. Organellen und andere Zelleinschlüsse finden sich ganz überwiegend in den dunklen osmiophilen Zonen und lassen regelmäßig eine bestimmte Anordnung erkennen. So ist häufig eine ringförmige Verteilung von Golgi-Feldern um den gelappten Kern vorhanden. Mitochondrien sind häufig in einem typischen „Axonhügel-Komplex“ angeordnet. Freie Ribosomen dominieren gegenüber membrangebundenen. Diese Neuronen sind reich an Glykogen, das oftmals ausgedehnte Felder einnimmt. Vereinzelt weisen die LRZ Faser-Soma-Synapsen auf.
    Notes: Summary The structure of the segmentally arranged somata of the dorsal giant fibres Günther, 1969) in the ventral nerve cord of the earthworms Lumbricus terrestris L., is described. These neurones are compared with other neurones of invertebrates and vertebrates. The paired lateral giant cells (LGC) are often multipolar in contrast to the single unipolar median giant cell (MGC). Up to four fibres originate from each LGC. The dotted appearance of both these neurones (clear and dark perikaryal areas) is due to the regular distribution of osmiophilic strands of cytoplasm containing the majority of organells and other inclusions (e.g. endoplasmatic reticulum and ribosomes). The majority of ribosomes are not associated with membranes but are found scattered freely in the cytoplasm. A typical “axon hillock” with an accumulation of mitochondria is often found. The cells show large deposits of glycogen. Some of the LGC-somata have synaptic contacts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00306591
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  • 16
    Electronic Resource
    Electronic Resource
    Die Anordnung der Ommatidien in der Retina der Biene (Apis mellifica L.) (1973)
    Springer
    Cell & tissue research 139 (1973), S. 567-582 
    Details
    ISSN: 1432-0878
    Keywords: Compound Eye ; Apis mellifica ; Polarized light ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung 1. Die Ausrichtung der Rhabdome ist in der Bienenretina nicht konstant. 2. Die Anordnung der exzentrischen Zellen in der Bienenretina ist ebenfalls nicht konstant, und es läßt sich keine symmetrische Verteilung dieser Zellen nachweisen. 3. Die Morphologie der Retina wird im Hinblick auf die Orientierung der Honigbiene nach dem Polarisationsmuster des vom blauen Himmel reflektierten Lichtes diskutiert.
    Notes: Summary 1. The orientation of the rhabdoms shows no regularity within the retina of the honeybee. 2. The arrangement of the eccentric cells is also irregular within the retina of the honeybee. 3. The morphology of the retina is discussed regarding the ability of the honeybees to orient according to the pattern of the polarization of light reflected from the blue sky.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02028393
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  • 17
    Electronic Resource
    Electronic Resource
    Le Système Nerveux des Cténaires (1973)
    Springer
    Cell & tissue research 137 (1973), S. 223-250 
    Details
    ISSN: 1432-0878
    Keywords: Nervous system ; Ctenophores ; Nerve-net, Nervous concentration ; Synapses ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A subectodermal nerve-net is demonstrated in ten species of Ctenophores by means of either Methylene Blue vital staining or silver impregnation. There is no evidence of subendodermal nerve-net. The ectodermal nerve-net displays a characteristic polygonal pattern which is thought to result from morphogenetic events. Both bipolar and tripolar neurones occur. Three types of concentrations of nervous tissue are described: a) a high accumulation of nervous perikarya at the aboral sensory pole; b) a noticeable densification of the net along the eight meridional ciliary strands of every species, and around the lips of Beroidea; c) in the Cydippids Pleurobrachia and Hormiphora two thick strands of fibers and neurones interconnecting the aboral organ and the tentacles: the tentacular nerves. Ultrastructural evidence is given for the presence of nervous elements under and amidst ectodermal epithelial cells. Three features allow the recognition and characterization of neurites and neurones: a) numerous clear and/or granulated vesicles; b) microtubules in variable amounts; c) frequent and highly differentiated synaptic contacts. The very peculiar arrangement of the presynaptic elements is observed in all the species of Ctenophores so far studied. These synaptic contacts suggest chemical transmission in the nerve-net. On the basis of ultrastructural evidence the author refutes the nervous nature previously attributed to the ciliated cells of the meridional grooves. A parallel is drawn between nervous systems of Cnidaria and Ctenophora.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307432
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    Electronic Resource
    Electronic Resource
    Electron microscopy of dental enamel: Analysis of crystal lattice images (1973)
    Springer
    Cell & tissue research 137 (1973), S. 271-280 
    Details
    ISSN: 1432-0878
    Keywords: Dental enamel ; Rat ; Ultrastructure ; Crystallography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Thin sections of rat incisor enamel were studied with the electron microscope. Fringe patterns having repeat periods in the range 3.1–8.2 Å were seen in individual enamel crystals. These images were interpreted as representing the resolution of corresponding planes in the hydroxyapatite crystal lattice. The lattice spacings and interplanar angles were identified by comparing the observations with available data derived from X-ray diffraction analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307434
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  • 19
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    Electronic Resource
    Ultrastructure of the pars distalis of the lizard Anolis carolinensis with special reference to the identification of the gonadotropic cell (1973)
    Springer
    Cell & tissue research 137 (1973), S. 293-312 
    Details
    ISSN: 1432-0878
    Keywords: Hypophysis ; Pars distalis ; Lizard ; Gonadotropic cell ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Five categories of granulated cells were distinguished by their ultrastructural features, and quantitative analyses were made of the pars distalis cells in normal and castrated lizards. The gonadotropin-producing cell was identified on the basis of its uniform distribution in the gland as well as from cytological changes resulting from castration. The secretory granules of the gonadotropic cell vary in size (100–500 mμ) and density, and lipid bodies are commonly present. Following castration, the endoplasmic reticulum proliferates, forming many small, rough-surfaced, dilated cisternae which do not coalesce greatly as in other vertebrate species. Degranulation is accompanied by hypertrophy and hyperplasia of the mitochondria and by the appearance in the cytoplasm of conspicuous clusters of microfilaments. The designated gonadotropic cell was the only class of secretory cell showing consistent changes following three weeks of castration. In addition to the uniformly distributed gonadotrope cell, two secretory cells occur mainly in the rostral half of the gland, and two in the caudal half. Tentative identification of the cell types is discussed in the light of available information on the localization of the hormones in the pars distalis of this species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307205
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  • 20
    Electronic Resource
    Electronic Resource
    Smooth muscle-like cells in ovaries of the hamster and gerbil (1973)
    Springer
    Cell & tissue research 140 (1973), S. 1-8 
    Details
    ISSN: 1432-0878
    Keywords: Ovary ; Smooth muscle ; Hamster ; Gerbil ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Smooth muscle-like cells are present in thecae externae, corpora lutea, and interstitial tissue of hamsters and gerbils. The smooth muscle-like cells, as examined by electron microscopy, are fusiform with central nuclei; the cytoplasm contains numerous myofilaments, dense bodies, micropinocytotic vesicles, and dense accumulations of glycogen-like particles. In addition to the smooth muscle-like cells, fibroblasts and cells that have characteristics of both fibroblasts and smooth muscle are located in the thecae externae of both species. There is no ultrastructural evidence of innervation in the theca folliculi, corpora lutea, or interstitial tissue of either species. A possible function for the smooth muscle-like cells is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307055
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  • 21
    Electronic Resource
    Electronic Resource
    Associations jonctions-organites cellulaires dans le foie néo-natal de souris (1973)
    Springer
    Cell & tissue research 140 (1973), S. 77-89 
    Details
    ISSN: 1432-0878
    Keywords: Intercellular junctions ; Neonatal liver ; Mouse ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé Au cours du passage de la vie foetale à la vie postnatale, on note, dans le foie de souris, l'apparition d'associations jonctions-organites cellulaires. Celles-ci cont de deux types: associations desmosomes-organites et associations nexus-organites. 1.Associations nexus-organites. Le long de la «gap junction» sont étroitement accolés, uni ou bilatéralement, divers organites: mitochondrie(s), subsurface cisterna(e), peroxysome(s) ou lysosome. Ces associations n'apparaissent qu'entre le 21ème jour de la gestation et le ler jour post-natal, période à partir de laquelle ils disparaissent au profit d'associations desmosomes-organites cellulaires. Un nouveau type de structure s'associe dans le foie aux membranes plasmatiques: il s'agit des saccules ergastoplasmatiques ou subsurface cisternae. 2.Associations desmosomes-organites. Dans ces complexes, les tonofilaments desmosomiques entrent étroitement en contact avec la paroi des organites cellulaires associés: mitochondrie ou peroxysome. Déjà présents au 13ème jour de la gestation, ces structures s'observent plus fréquemment à partir du ler jour post-natal. La signification de ces associations reste à déterminer, d'autant plus que leur présence a déjà été signalée dans de trés nombreux tissus. Quelques hypothèses sont présentées.
    Notes: Summary During the transition between the fetal and postnatal periods associations between cell junctions and cell organelles appear in the liver of the mouse. These associations are of two types: desmosome-organelle and nexus-organelle. 1.Nexus-Organelles Association. Unilaterally or bilaterally, various organelles — mitochondria, cysternae, microbodies or lysosomes — adhere tightly along the gap. These associations appear only between the 21st day of gestation and the first postnatal day. Thereafter they gradually disappear and are replaced by desmosome-organelle associations. Another type of structure — ergastoplasmic saccules or cisternae of rough endoplasmic reticulum — become associated with the cell membrane. 2.Desmosome-Organelle Associations. In these complexes the desmosomal microfilaments are in close contact with membranes of the associated organelles — mitochondria or peroxysomes. The associations, which exist as early as the 13th day of gestation increase after the first postnatal day. The significance of these associations remains to be ascertained, especially since they occur in many other tissues. A few hypotheses are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307059
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  • 22
    Electronic Resource
    Electronic Resource
    Fine structural alterations with age in the fat body of the adult male housefly, Musca domestica (1973)
    Springer
    Cell & tissue research 140 (1973), S. 169-175 
    Details
    ISSN: 1432-0878
    Keywords: Fat body ; Housefly ; Aging ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fat body of the adult housefly is composed of two types of cells, the lipid-and glycogen-rich fat body cells and the oenocytes. A comparison of the fine structure of the abdominal fat body in 4-day old and 31–35 day old male houseflies indicated an increase in lipid and a decrease in glycogen content in the fat body cells of old flies. Oenocytes of old flies exhibit deteriorative alterations with an accumulation of secondary lysosomes. Both fat body cells and oenocytes in senile flies are ingested by hemocytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00306692
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  • 23
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    Electronic Resource
    L'innervation du lophophore chez le Bryozoaire chilostome Electra pilosa (L.) (1973)
    Springer
    Cell & tissue research 140 (1973), S. 217-234 
    Details
    ISSN: 1432-0878
    Keywords: Tentacles ; Electra pilosa ; Nerves ; Bielschowsky technique ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé Le trajet des grands nerfs de la couronne tentaculaire et la structure du collier nerveux péripharyngien dont ils se détachent, ont été précisés chez Electra pilosa par des imprégnations argentiques in toto selon la technique de Bielschowsky et par une étude d'ultrastructure. Chaque tentacule est innervé par quatre faisceaux nerveux, dépourvus d'envelope gliale, qui courent entre l'épithélium et l'assise collagène qui délimite le canal tentaculaire interne; trois sont rassemblés sous les trois rangées cellulaires épithéliales de l'arête orale du tentacule et le quatrième est médian-dorsal. Les cellules épithéliales orales-latérales, par leur forme pédonculée, par la densité de leur cytoplasme, par leur cil unique et par leur relation topographique et cytologique avec les nerfs tentaculaires sous-jacents, présentent des adaptations structurales telles qu'il parait probable qu'elles assurent une fonction tactile. L'examen du collier péripharyngien montre son caractère organisé et la complexité des connexions qui coordonnent l'ensemble des tentacules et relient le lophophore à d'autres secteurs de l'innervation.
    Notes: Summary The pathway of the tentacle nerves and the organisation of the peripharyngial nervous belt from which they arise, have been studied in Electra pilosa by silver stained whole mounts (Bielschowsky technique), and by ultrastructural investigation. Each tentacle is innervated by four nervous fascicles without any differentiated glial sheath, running between the epithelium and the collagen layer which surrounds the muscles and the peritoneal cells in the internal tentacle canal. Three nerves are gathered underneath the three rows of epithelial cells forming the oral edge of the tentacle. The fourth nerve is in medio-dorsal location. The oral epithelial cells show such ultrastructural adaptations in their general shape, in the density of their cytoplasm, in their ciliary apparatus reduced to a single cilium and in their close topographical and cytological relationship with the underlying tentacle nerves that it seems most probable they have a tactile function. The analysis of the pattern of the peripharyngial nervous belt shows a precise organisation and the intrication of the connections which coordinate the tentacles and link the lophophore set to other pathways of general innervation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00306696
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  • 24
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    Electronic Resource
    Suppression of somatotrophs in growth hormone injected rats (1973)
    Springer
    Cell & tissue research 140 (1973), S. 309-314 
    Details
    ISSN: 1432-0878
    Keywords: Pituitary Gland ; Rat ; Somatotropin ; Cellular Response ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The response of somatotrophs to large doses of purified bovine growth hormone was examined in uninephrectomized rats drinking 1% sodium chloride in an attempt to prolong the action of the hormone. Growth hormone produced a triphasic response in the ultrastructure of somatotrophs. Uninephrectomy and salt alone induced no changes in somatotrophs as compared to unoperated animals consuming tap water. In the first phase (3 days) the cross sectional area of the cell increased, the size of the largest granule per cell as well as the number of granules per cell increased significantly. All these parameters then reached control level after 7 days of injections during a second phase. Suppression of somatotrophs by exogenous growth hormone was evident by 16 days (third phase) when the area of the cell, the size of the largest secretory granule as well as the number of granules per cell all decreased significantly. Somatotrophs apparently did not react to suppression by a lysosomal mechanism inasmuch as no increase in the number of lysosome-derived structures was seen even at 16 days.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307020
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  • 25
    Electronic Resource
    Electronic Resource
    Ultrastructural aspects of mouse cecal epithelium (1973)
    Springer
    Cell & tissue research 140 (1973), S. 445-449 
    Details
    ISSN: 1432-0878
    Keywords: Cecum, Colon ; Mouse ; Glycocalyx ; Intestinal microorganisms ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the cecal epithelium of the mouse resembles that of more distal parts of the colon. A brief discussion is presented of the possible significance of apical cytoplasmic granules to the glycocalyx and of the close association of microorganisms with the lining epithelium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00306671
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  • 26
    Electronic Resource
    Electronic Resource
    Fine structure of the adenohypophysis in immature sockeye salmon, Oncorhynchus nerka (1973)
    Springer
    Cell & tissue research 140 (1973), S. 459-471 
    Details
    ISSN: 1432-0878
    Keywords: Adenohypophysis ; Sockeye salmon ; Cell types ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the secretory cells of the adenohypophysis of juvenile sockeye salmon was investigated. Pituitary glands were collected from immature fish transferred experimentally to sea water and subsequently returned to fresh water. The rostral pars distalis contained three cell types: ACTH cells, prolactin cells, and non-secretory cells. The prolactin and non-secretory cells were joined together in the form of follicles by desmosomes and they both had cilia and microvilli projecting into the follicle lumen. Various follicular structures such as lumen, multivesicular structures, and peripheral basement membrane are discussed as possible sites of prolactin cell granule release. The columnar ACTH cells were found at the junction of the rostral pars distalis and the neurohypophysis. The cytoplasmic granules in these cells were characteristically separated from their limiting membrane by a clear space. Multivesicular structures were also found in association with this cell type. The caudal pars distalis also contained three cell types: one acidophil (putative somatotrop) and two basophils (putative thyrotrops and gonadotrops), all of which were similar to those described in adult fish. The pars intermedia contained only one cell type. They appeared to be active cells and were characterized by containing membrane-bounded granules similar to those found in the ACTH cells. Changes in ambient salinity had no apparent effect on any cell type described.
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    URL: http://dx.doi.org/10.1007/BF00306673
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  • 27
    Electronic Resource
    Electronic Resource
    Fine structure of eyespots in tornarian larvae (Phylum: Hemichordata) (1973)
    Springer
    Cell & tissue research 142 (1973), S. 89-102 
    Details
    ISSN: 1432-0878
    Keywords: Photoreceptors ; Larva ; Hemichordate ; Ultrastructure ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The eyespots of tornariae of enteropneusts (Ptychodera flava from Hawaiian waters and an unknown species from southern California) were studied by electron microscopy. An ocellus is composed of two types of cells: sensory and supportive. The former is characterized by a bulbous cilium (with 9+2 axoneme) at its distal end, one or sometimes two arrays of microvilli from its sides below the cilium, and a basal axon. The latter features large, clear vesicles which presumably contained the reddish-orange pigment seen in the ocellus of a living larva. Five-day old tornariae of P. flava are positively phototactic. Both cilium and microvilli may function as photoreceptors. The tornarian ocellus studied is compared with eyespots of other invertebrates, and the evolutionary significance of its putative photoreceptors is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00306706
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  • 28
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    Electronic Resource
    La spermiogenèse d'Albula vulpes (L. 1758) (Poisson Albulidae) (1973)
    Springer
    Cell & tissue research 142 (1973), S. 171-192 
    Details
    ISSN: 1432-0878
    Keywords: Spermiogenesis ; Teleost ; Albula vulpes ; Flagella ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé La jeune spermatide possède un noyau arrondi, un diplosome proche de la membrane cellulaire auquel sont associées des formations paracentriolaires; une mitochondrie unique est disposée entre le diplosome et le noyau. Au cours de l'évolution de la spermatide, le noyau s'allonge latéralement, son grand axe étant perpendiculaire à l'axe flagellaire; la mitochondrie migre à l'extrémité latérale du noyau; le centriole distal donne un flagelle de type 9+0; le centriole proximal se prolonge le long du noyau puis sort de la cellule sous la forme d'un pseudo-flagelle. Le prolongement centriolaire est constitué de triplets classiques et de doublets d'un type particulier que nous avons appelés «doublets A–C». Les auteurs signalent la similitude des spermatozoïdes de cet Elopiforme avec les spermatozoïdes d'Anguilliformes ce qui serait en faveur de la proposition de Greenwood et al. de rassembler ces téléostéens dans le super-ordre des Elopomorphes.
    Notes: Summary The early spermatid possesses a round nucleus and a diplosome which is close to the cellular membrane and with which paracentriolar formations are associated; a sole mitochondrion is located between the diplosome and the nucleus. During the spermatid evolution, the nucleus is laterally elongated, its main axis being perpendicular to the flagellar axis; the mitochondrion migrates towards the lateral end of the nucleus; the distal centriole is extended along the nucleus, then leaves the cell as a pseudoflagellum. This centriolar extension is made up of regular triplets and of a particular type of doublets that we have called “A–C doublets“. The authors call attention to the similarity between the spermatozoa of this Elopiforme and the spermatozoa of the Anguilliformes. This observation favours Greenwood et al.'s proposition, to place these teleost into the super-order of Elopomorpha.
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    URL: http://dx.doi.org/10.1007/BF00307031
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  • 29
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    Electronic Resource
    Feinstruktur der Luteinzellen des Meerschweincheneierstocks während der Schwangerschaft und des Zyklus (1973)
    Springer
    Cell & tissue research 142 (1973), S. 525-537 
    Details
    ISSN: 1432-0878
    Keywords: Lutein cells ; Guinea pig ; Sexual cycle ; Pregnancy ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die Feinstructur der Luteinzellen des Meerschweinchens während Schwangerschaft (15., 35., 45., 50., 55., 63. und 2 Tage nach der Geburt) und Zyklus (9, 14, 16, 20 Tage nach der Ovulation) wurden elektronenmikroskopisch untersucht. In den aktiven Luteinzellen kann man konzentrisch um die Lipoidtropfen angeordnete Strukturen des agranulären endoplasmatischen Retikulum beobachten, die später durch Membranstrukturen des granulären endoplasmatischen Retikulum ersetzt werden. Die Mitochondrien sind rund und enthalten tubuläre Innenstrukturen, die Lipoidtropfen sind elektronenoptisch dicht. Während der Rückbildung des Corpus luteum setzt sich das endoplasmatische Retikulum aus ungeordneten Vesikeln und Tubuli zusammen, die Mitochondrien sind länglich oder verzweigt, die Lipoidtropfen elektronenoptisch hell. Die Bedeutung dieser feinstrukturellen Veränderungen in der Luteinzelle wird diskutiert.
    Notes: Summary The fine structure of the lutein cells in guinea pigs corpora lutea of pregnancy (15th, 35th, 45th, 50th, 55th, 63th day and 2 days after birth) and during oestrous cycle (9, 14, 16, 20 days after ovulation) is described. During the active phase of the corpus luteum the formation of concentric whorls of agranular endoplasmic reticulum around lipid droplets is observed, but later the granular endoplasmic reticulum increases. In this stadium the mitochondria are round with tubulous cristae and the lipid droplets are increased in density. During the involution of the corpus luteum the endoplasmic reticulum does not form concentric whorls, the mitochondria are elongated, polymorphic, the lipid droplets have lower electron density. These ultrastructural changes in the lutein cells are discussed concerning the role of the cell organelles in the steroid synthesis.
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    URL: http://dx.doi.org/10.1007/BF00306713
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  • 30
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    Electronic Resource
    Licht- und elektronenmikroskopische Untersuchungen an den Leydigzellen des Schweines während der postnatalen Entwicklung (1973)
    Springer
    Cell & tissue research 143 (1973), S. 207-227 
    Details
    ISSN: 1432-0878
    Keywords: Testis interstitial cells ; Boar ; Postnatal development ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Die postnatale Ontogenese der Hodenzwischenzellen des Schweins nimmt einen wellenförmigen Verlauf und läßt sich in 4 Phasen unterteilen. In der frühpostnatalen Proliferationsphase wandeln sich spindelförmige Zellen in polygonale Leydigzellen um. Dabei beginnt an einem Zellpol die Ausbildung des glatten endoplasmatischen Retikulums. Dieses Organell nimmt in der weiteren Entwicklung einen großen Teil des Zelleibes ein und bildet unregelmäßige Vesikel und konzentrisch geschichtete Zisternen. Es erfolgt eine Vermehrung der Mitochondrien, in ihnen entwickeln sich Tubuli. In der Phase der präpubertären Hypertrophie erreichen die Leydigzellen ihre größten Durchmesser (ca. 30 μm) und sind möglicherweise zu einer Steroidhormonproduktion befähigt. Da das glatte endoplasmatische Retikulum vornehmlich in der Zellperipherie, die übrigen Organellen bevorzugt im Zentrum liegen, sind die Zwischenzellen deutlich zoniert. Die Phase der präpubertären Regression ist durch ausgeprägte Zelldegeneration und Größenabnahme der überlebenden Zellen gekennzeichnet. In der Phase der pubertären Proliferation nehmen die Zwischenzellen erneut an Größe zu. Parallel hierzu vermehren sich Mitochondrien und glattes endoplasmatisches Retikulum. Beide Proliferationsphasen innerhalb der postnatalen Ontogenese werden durch das Auftreten zahlreicher Cytoplasmafilamente eingeleitet, deren Menge sich danach wieder verringert. Unabhängig von dem wellenförmigen Verlauf der Zwischenzellentwicklung ist die Ausbildung von Lysosomen, Microbodies, Mikrovilli, typischen Zellhaften und in der Zellperipherie gelegenen Polyribosomen. Die Leydigzellen sind von einer basalmembranähnlichen Struktur umgeben. Die Mitochondrien enthalten zu allen Zeiten durch elektronendichtes Material verkittete Tubuli.
    Notes: Summary The postnatal development of porcine testicular interstitial cells proceeds in a wave-like manner and may be divided into four periods. In the period of early postnatal proliferation fusiform intertubular cells change into polygonal Leydig cells. This process starts with formation of smooth endoplasmic reticulum in one of the cell poles. Later the smooth endoplasmic reticulum is abundant and consists of irregular vesicles and concentrically arranged cisterns. Mitochondria increase in number and develop tubular cristae. In the period of prepubertal hypertrophy Leydig cells reach maximal size (approx. 30 μm) and possibly may be capable of androgen biosynthesis. The cells of this period exhibit two different zones, since the smooth endoplasmic reticulum prefers the periphery, the other organelles, however, occupy the central region of the cells. The period of prepubertal regression is characterized by cellular degeneration and diminuation of the surviving interstitial cells. In the period of pubertal proliferation an increase of Leydig cell size is accompanied by multiplication of mitochondria and development of smooth endoplasmic reticulum. Both periods of proliferation are initiated by appearance of numerous cytoplasmic filaments which subsequently decrease in number. Interstitial cells of all periods studied exhibit the following features: They possess lysosomes, microbodies, polyribosomes, microvilli and are surrounded by a kind of basement membrane. Cell connections appear as tight junctions and desmosome-like structures. The mitochondria contain closely packed tubules joined by electron dense material.
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    URL: http://dx.doi.org/10.1007/BF00307479
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    An ultrastructural study of the synaptic densities, nematosomes, neurotubules, neurofilaments and of a further three-dimensional filamentous network as disclosed by the E-PTA staining procedure (1973)
    Springer
    Cell & tissue research 143 (1973), S. 239-272 
    Details
    ISSN: 1432-0878
    Keywords: Nervous tissue ; Specific structures ; Nematosomes ; Neurofilaments ; Neurotubules ; Three-dimensional filamentous network ; E-PTA Stain ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary After the staining of nervous tissue with phosphotungstic acid in absolute ethanol (E-PTA), a selective opacification occurs at certain specific sites, while other structures, especially the plasma and intra-cellular membranes, remain electron-lucent. Among those selectively stained sites, our studies have been focussed on: (1) The dense synaptic material consisting of several presynaptic clumps, termed projections, an intrasynaptic dense line and a subsynaptic web from which fine fibrillar wisps extend into the surrounding ground substance; (2) Neurofilaments and neurotubules, the surface of which is bristled by numerous side-arms; (3) A microfilamentous network intertwines the neurotubules, the neurofilaments and the mitochondria in the dendrites and axon, and is also connected to the E-PTA dense undercoating delineating the inner aspect of the plasma membrane and to the fine wisps emanating from the subsynaptic web. A three-dimensional microfilamentous latticework is thus formed in the nerve cell processes; (4) Dense cytoplasmic inclusions, termed nematosomes, which are usually located in the ground substance of the perikaryon among or in the vicinity of clusters of ribosomes. Tiny microfilaments emanate from the peripheral strands of these bodies. The presence of basic residues in the chains of structural proteins of which consist the subsynaptic web and the nematosome is plausible, since the specificity of the E-PTA staining procedure for the detection of basic residues has previously been put forth. The occurrence of a three-dimensional microfilamentous network in the nerve cell processes led us to hypothesize that it plays a role in translocation of materials. It may provide the motive force for the axoplasmic transport, for instance, with the neurotubules, as well as, plausibly, with the neurofilaments, serving as attachment sites and guideways.
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    URL: http://dx.doi.org/10.1007/BF00307481
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  • 32
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    Ultrastructural studies of oogenesis in some european amphibians (1973)
    Springer
    Cell & tissue research 143 (1973), S. 387-407 
    Details
    ISSN: 1432-0878
    Keywords: Oogenesis ; Urodela ; Yolk-formation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Oogenesis was studied in adult Triturus vulgaris (Urodela) with the electron microscope. The oocytes investigated ranged between 50 μm and 1600 μm in diameter. Two types of yolk platelet formation were found. Since both types involve the incorporation of high numbers of pinocytotic vesicles they are believed to be of an extraoocytic origin. On the basis of the order of their appearance they were named primary and secondary yolk. Five different types of vesicles were found, which participate in a variety of activities, such as yolk formation and the formation of the Golgi apparatus. They originate from four different sources, namely the nuclear membrane, the cytoplasm in connection with ribosome-like particles, the Golgi apparatus and the plasma membrane through pinocytosis. The results obtained were discussed especially with respect to differences found between the anura and the urodela, such as the presence or absence of cortical granules or equivalent structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307423
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    Electronic Resource
    Electronic Resource
    Electron microscopic study on the larval and adult corpus allatum of Oncopeltus fasciatus dallas (insecta, heteroptera) (1973)
    Springer
    Cell & tissue research 145 (1973), S. 447-458 
    Details
    ISSN: 1432-0878
    Keywords: Corpus allatum ; Oncopeltus fasciatus ; Larvae ; Imagines ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. The ultrastructure of the corpora allata of last larval instars and adults of Oncopeltus was studied. The unpaired gland undergoes submicroscopic alterations and shows signs of degradation in old animals. The organ is partly covered and penetrated by corpus cardiacum tissue. Axons with different types of neurosecretory granules form synaptoid contacts with the corpus allatum cells. 2. “Dark” and “light” gland cells can be differentiated on account of the degree of electron density. The former predominate during the last larval stage and in the young imago, the latter in mature males and females. It is highly probable that the “light” cells are the active (i.e. hormone producing) ones and the “dark” cells the inactive ones. 3. The active cells are characterized by rough endoplasmatic reticulum (often in whorls), small amounts of smooth endoplasmatic reticulum and many multivesicular bodies. Abundant free ribosomes, a not particularly well developed Golgi apparatus, dense bodies, and cytolysomes are present in active and inactive cells. 4. The nuclei contain one to four prominent and variously shaped nucleoli, which show differences between adult males and females with respect to their location in the nucleus. 5. The corpus allatum cells of Oncopeltus are obviously engaged in extensive protein synthesis. Tangible structural indications for the manufacture of juvenile hormone were not observed. Possible sites of hormone release are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00306717
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  • 34
    Electronic Resource
    Electronic Resource
    Electron microscopic study of the substantia nigra and the strio-nigral projection in the rat (1973)
    Springer
    Cell & tissue research 146 (1973), S. 207-221 
    Details
    ISSN: 1432-0878
    Keywords: Substantia nigra ; Rat ; Six bouton types ; Strio-nigral projection ; Bouton degeneration ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The normal ultrastructure of rat substantia nigra was investigated. Special attention was paid to the different types of boutons, and the mode of termination of the striatonigral connection was examined. Two different types of nigra neurons with deep nuclear membrane indentations were observed. The synaptic organization of rat substantia nigra is very complex. Six types of boutons, with many characteristics, could be differentiated: pleomorphicvesicle boutons (40%), elongated-vesicle boutons (10%), small-round-vesicle boutons (10%), large-round-vesicle boutons (20%), “clear-terminal” (15%) and dense-core-vesicle boutons (about 5%). Vesicle-containing dendrites were observed entering dendro-dendritic synapses. One to four days after large unilateral striatal lesions were made, a great number of degenerating boutons were seen in the ipsilateral substantia nigra, while the contra-lateral substantia nigra was entirely free of degeneration. The newly defined pleomorphic-vesicle boutons were found almost exclusively in the process of degeneration. The neuronal origin of the other bouton types is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307347
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  • 35
    Electronic Resource
    Electronic Resource
    Fine structure of capillaries in the pecten oculi of the sparrow, Passer domesticus (1973)
    Springer
    Cell & tissue research 146 (1973), S. 281-292 
    Details
    ISSN: 1432-0878
    Keywords: Eye ; Bird ; Pecten oculi ; Capillaries ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pecten oculi of the sparrow consists of capillaries, pigment cells and a superficial membrane. Because of the loose structure of the first two components broad intercellular spaces occur in the pecten. The capillary wall consists of endothelial cells and a perivascular membrane. The bodies of the endothelial cells are flattened, while the plasmalemma of both their surfaces (basal and luminal) is strongly folded and forms numerous microfolds with an average thickness of 700 Å. The height of the inner microfolds is 1.4–1.8 μm, the outer microfolds measure 1.3–1.6 μm. They lie densely packed side by side and are separated by recesses of the capillary lumen ca. 500 Å wide. Due to this the surface of the endothelial cell is increased by approximately 20-fold. The adjoining endothelial cells abut or overlap with margins, and are joined by the zonulae adherentes. Pigment cells form numerous processes and microvilli. Some rest on the capillary walls, while others penetrate the superficial membrane of the pecten or fill the intercellular spaces.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307352
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  • 36
    Electronic Resource
    Electronic Resource
    Axon retraction following guanethidine treatment (1973)
    Springer
    Cell & tissue research 146 (1973), S. 439-451 
    Details
    ISSN: 1432-0878
    Keywords: Sympathetic neurons ; Axon retraction ; Guanethidine ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Vasa deferentia of rats chronically treated with high doses of guanethidine sulphate (30 or 60 mg/Kg/day i.p.) were examined using electron microscopic, fluorescence histochemical and pharmacological techniques. Counts of the axon population in segments of the proximal (urethral) end of the vas deferens showed a reduction to approximately 55% and 35% in the number of axon profiles after treatment for one week with the two dose levels respectively. In the same period only a few cell bodies in the hypogastric ganglion (from which most of the adrenergic innervation of the vas deferens arises) reached the stage of terminal degeneration. Although many axons showed some abnormalities, the number of axons observed in terminal stages of degeneration in treated tissue did not exceed, at any stage examined, the very small numbers observed in control tissue. Organ bath studies showed that the contractile response to transmural stimulation was lost fastest at the distal (epididymal) end of the treated vas deferens. These results have led to the conclusion that, in contrast to the degeneration of adrenergic axons produced by surgery or 6-hydroxydopamine, the sympathectomy produced by guanethidinein vivo involves theretraction of adrenergic axons prior to complete degeneration of the cell bodies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02347174
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  • 37
    Electronic Resource
    Electronic Resource
    Ultrastructure of nerve terminals and muscle fibers in denervated crayfish muscle (1973)
    Springer
    Cell & tissue research 146 (1973), S. 155-165 
    Details
    ISSN: 1432-0878
    Keywords: Muscle ; Crayfish ; Synapse ; Degeneration ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Neuromuscular junctions, muscle fibers, and intramuscular nerve branches in crayfish opener muscles denervated for periods up to 368 days were examined with the electron microscope. The majority of the denervated muscles responded to stimulation of the isolated distal part of the motor axon with electrical activity and contractions. The neuromuscular junctions and muscle fibers appeared normal in such preparations: synapses and synaptic vesicles were present in the nerve terminals, and the organization of filaments and tubules in the muscle fibers was not distinguishable from that in normal muscles. In some preparations denervated for a long time, and in others denervated by tying the motor axon close to the muscle, the motor axons showed physiological and morphological evidence of degeneration. Synapses, when present in such preparations, showed few synaptic vesicles, which were often clumped. Muscle fibers showed signs of degeneration. These observations suggest that isolated distal motor axon segments can remain alive for at least a year, retaining normal structure. As long as the motor axon is viable, the muscle remains normal in appearance, but if the axon degenerates, the muscle becomes abnormal. A trophic interdependence between nerve and muscle is probably involved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307344
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  • 38
    Electronic Resource
    Electronic Resource
    Block and graft polymers their synthesis, especially by living polymer technique, and their properties (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 1-9 
    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 various structures encountered in block and graft polymers are reviewed and a nomenclature useful for the description of these macromolecules is proposed. The concept of living polymers is elucidated and its ramifications discussed. It is shown how greatly the control of polymerization and the uniformity of the products is improved when living polymers are used as the reagents. Their application in the synthesis of block and graft polymers is illustrated by numerous examples. Other synthetic techniques yielding block and graft polymers are briefly sketched, their advantages and shortcomings being considered. Properties of block and graft polymers are described, special attention being devoted to the problems of mesomorphic phases and to the morphology of block polymers. The incompatibility phenomena observed in block and graft polymer systems are compared with those encountered in studies of the polymeric blends.Finally, the present and future applications of block and graft polymers are considered and their potential evaluated.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130102
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  • 39
    Electronic Resource
    Electronic Resource
    The mechanical behavior of thermoplastic materials in the deep drawing process (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 65-73 
    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 study presents a mechanical analysis of the deep drawing of thermoplastics in the glassy state. A theoretical stress analysis is conducted by applying principles of classical plasticity together with several assumptions. A simple model is presented relating drawing performance with the mechanical properties of the plastic measured under the conditions of the fabrication operation. An experimental procedure is described for evaluating the drawability of a plastic. Data on thirteen thermoplastics are used to demonstrate the applicability of the theory developed.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130111
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  • 40
    Electronic Resource
    Electronic Resource
    Scanning electron fractography of lap-shear joints (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 40-45 
    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: Fracture surfaces of Epon 901/B-3 bonded aluminum alloy joints in the lap-shear configuration were studied using scanning electron microscopy. Major differences in the appearance of the fracture surface from those reported (8) for tensile loaded joints at 23°C are produced either by cyclic loading at 23°C or a change in test temperature to -196°C. Fracture in tensile loaded joints at -196°C is a brittle single step process in the opening mode in which rapid crack extension occurs throughout the joint with very little adhesive flow. Tensile fatigue fracture at 23°C is in the opening mode but crack extension is complicated by extensive adhesive flow throughout the entire joint.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130107
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  • 41
    Electronic Resource
    Electronic Resource
    Effect of rubber particle size on deformation mechanisms in glassy epoxy (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 29-34 
    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: When tested in tension, a cross-linked epoxy resin can be made to exhibit shear yielding. A modified von Mises criterion, τ = τ0 - μP describes the yielding behavior of the same resin under a biaxial stress system, indicating that the flow of the material is pressure sensitive.Butadien-acrylonitrile elastomer particles suspended in the cross-linked epoxy matrix induce large local deformations when the composite material is stressed. Particles a few hundred Angstroms in diameter cause the glassy matrix to exhibit shear banding, and the macroscopic failure envelope of such a system follows a modified von Mises criterion similar to that of the matrix resin. It was found that the coefficient of internal friction, τ, and the activation energy for yielding are approximately the same for the two cases. With larger particles (5-15,000 Å diam) the failure mode changes as shown by the macroscopic yield envelope and the associated activation energy. Electron micrographs of the fracture surfaces show microcavitation, similar to crazing around each particle; the deformed glassy polymer around each particle retracts upon heating the matrix above its Tg. The fracture surface work value of the unmodified matrix is 1.75 × 105 ergs/cm2. With 10 pph small particles, the value increases to 3.32 × 105 and with 10 pph of large particles, to 15.48 × 105 ergs/cm2.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130105
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  • 42
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    Electronic Resource
    Kinetics and thermal characterization of thermoset cure (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 59-64 
    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 differential scanning calorimeter (Perkin-Elmer DSC-1) is used to characterize the cure of a general-purpose polyester during isothermal and scanning experiments. The technique is based on a new proposed model for the kinetics of isothermal cure. The model yields results which are in good agreement with experimental isothermal rate of reaction and integral heat of reaction data. It also gives some information about the residual reactivity of the sample after an isothermal cure experiment. With the aid of the proposed kinetic model, it is possible to obtain integral heats of reaction and rates of heat generation at different temperatures during a scanning experiment. The difference between the rate of heat input to the sample and the heat of reaction at any instant during scanning may be used to calculate the specific heat of the sample at the same instant. Specific heat data show two maxima during each scanning experiment. These maxima may be associated with transitions occurring during cure in the melt and rubbery states.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130110
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  • 43
    Electronic Resource
    Electronic Resource
    Variables affecting parison diameter swell and their correlation with rheological parameters (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 153-159 
    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 important factor in the selection of blow molding resins for producing handled bottles is the effective diameter swell of the parison. Ideally, the diameter swell is directly related to the weight swell and would require no separate consideration. In actual practice, the existence of gravity, the finite parison drop time and the anisotropic aspects of the blow molding operation prevent reliable prediction of the parison diameter swell directly from the weight swell.The parison diameter swell is a complex function of the weight swell, the rate of swell and the melt strength. Elements of this function are presented which show the effect of extrusion rate, parison drop time and parison weight.A technique is presented which allows the estimation of local weight and diameter swell ratios. Their direct relationship is confirmed by data obtained on several blow molding resins. The relationship between weight swell and diameter swell is definitely anisotropic.A mathematical model for swell is proposed which incorporates experimentally determined rate constants and swell coefficients. Correlations are given which suggest fundamental relationships between these derived coefficients and basic variables such as resin properties or process conditions. The model's predictive capability is demonstrated by using it to back calculate parison dimensions.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130212
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  • 44
    Electronic Resource
    Electronic Resource
    Chlorinated polyethylene modification of blends derived from waste plastics. Part II: Mechanism of modification (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 308-318 
    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: Previous publications have shown that the stress-strain behavior, especially ductility, of some incompatible polymer blends are greatly improved by the addition of slurry produced chlorinated polyethylenes (CPE). This improvement is greatest for blends containing polyethylene and PVC. The most effective CPE's have some residual polyethylene crystallinity and may be described as block-like polymers with ethylene sequences and chlorine containing sequences. It is postulated that CPE addition improves the blend properties by increasing the adhesion between domains in the blend via interactions with the blend components. This hypothesis was explored by thermal analysis, dynamic mechanical testing, adhesion studies, and microscopy. It is concluded that the interaction of CPE with polyethylene derives from compatibility of rather long methylene sequences in CPE with the polyethylene which results in good adhesive bonding. The interaction of CPE with PVC may not be owing to segmental compatibility but simply good mutual adhesion between similar polar materials. There is no interaction or adhesion between CPE and polystyrene as would be expected. CPE addition to blends is accompanied by a decrease in component domain size. The relationship between CPE structure and its effectiveness as a blend modifier is discussed.
    Additional Material: 22 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130411
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  • 45
    Electronic Resource
    Electronic Resource
    Flow properties of poly (vinyl chloride) (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 322-336 
    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 detailed review of the material published to date on the flow properties of poly(vinyl chloride) is given. The dependence of viscosity on concentration molecular weight, molecular weight distribution, shear and temperature for concentrated and molten poly (vinyl chloride) is considered. Polymer blends and plastisols are also included.
    Additional Material: 40 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130503
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  • 46
    Electronic Resource
    Electronic Resource
    Interpretation of the “melt strength” test (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 342-345 
    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 “melt strength” test for molten polymers is shown to be a function of several rheological parameters. Interpretation of results in terms of extensional viscosity differences is consequently not straightforward, if possible at all.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130505
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  • 47
    Electronic Resource
    Electronic Resource
    Effect of an epoxidized novolac resin anhydride structure on the properties of resin (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 357-364 
    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: The properties of an epoxidized novolac resin cured with two homologous series of substituted succinic anhydrides (alkenyl and alkyl) have been determined and the effects of anhydride structure on properties have been evaluated. Substituted succinic anhydrides yield cured resins with lower strengths, lower heat distortion temperatures, and lower moduli. Use of substituted succinic anhydrides could broaden the range of application of alicyclic anhydrides to include those requiring a more flexible resin. Effects of specific elements of anhydride structure have been consistently interpreted from properties measurements and from aging and solvent resistance studies.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130507
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  • 48
    Electronic Resource
    Electronic Resource
    Effect of fiber-matrix adhesion on the properties of short fiber reinforced ABS (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 409-414 
    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 tensile strength, fracture energy, and impact strength of ABS reinforced with discontinuous crystalline fibers such as FybexDu Pont trademark. can be controlled by manipulating fiber-matrix interfacial adhesion. In “good bonding” situations composite tensile strength, thermal expansion coefficient, and elastic moduli are significantly improved over the unfilled resin. The excellent impact strength of unreinforced ABS can be retained by lowering the fiber-matrix interfacial adhesion. This results in a corresponding reduction in the improvements in tensile and flexural strength. However, the elastic moduli and thermal expansion coefficients are relatively insensitive to changes in adhesion. Consequently, a material with high modulus (〉500,000 psi), high Izod impact resistance (7.0 ft-lb/in.), and low expansion coefficient (3.0 × 10-5 in./in./°F) can be obtained. A material with this unique combination of properties should find use in large parts such as camper tops, truck grilles, and snowmobile bodies.Fiber-matrix adhesion was measured directly by an x-ray analysis technique which could be employed because of the fiber's crystallinity and unique growth habit. This independent measurement allowed a correlation between bonding and composite properties. The interfacial bond strength was manipulated by a variety of fiber coatings and resin additions.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130603
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  • 49
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    Electronic Resource
    Measurement of oxidation stability of polyolefins by thermal analysis (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 415-421 
    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: Differential thermal analysis (DTA) is well known for measuring temperatures and heats of physical and chemical transitions in materials. Recent development work on improved stabilization systems for polyolefin wire insulations has required fast procedures for measuring the performance of stabilization systems. Isothermal DTA procedures have been developed into routine tools for measuring stability of polyolefins by determining the oxidative induction time at elevated temperatures.Oxidative induction time has been used to study the stability of polyethylene and polypropylene in raw material form and on wire. The dependence on temperature and antioxidant concentration have been measured. Effects of oxidation catalysts, catalyst deactivators and various environmental exposures are readily observed. Techniques and apparatus have been developed for simultaneous testing of a multiplicity of samples, providing for economical large scale use of the method.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130604
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  • 50
    Electronic Resource
    Electronic Resource
    Unsteady-state heat transfer in a crystallizing polymer (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 10-16 
    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 processing of polymers typically includes steps involving heat transfer, such as quenching and crystallization. The mechanical properties of a polymer are thus affected by processing conditions, such as the amount of time spent by each portion of the polymer at each temperature in the processing sequence.This paper presents the results of a mathematical modeling study of the unsteady-state temperatures inside a crystallizing polymer during quenching. This model differs from usual methods in including temperature dependence of induction times and kinetic processes, and in not treating the polymer as a simple, small molecule system. The model permits the prediction of the final morphological distribution within the polymer. Use of the model will aid in tailoring processing conditions to produce a product with specified morphology. The method is applicable to a wide variety of problems in polymer processing, particularly for those polymers which exhibit crystallization.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130103
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    Masthead (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973) 
    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.760130201
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  • 52
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    Flow and heat transfer in screw extruders: I. A variational analysis applied in helical co-ordinates (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 209-215 
    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 variational analysis is applied in helical co-ordinates to the problem of a developed, steady-state flow in a screw extruder. The functional involves only two dimensionless coordinates and is suitable for minimisation, e.g. by the finite element method. It is applicable to non-isothermal, purely viscous flows and contains terms representing effects of inertia, convective and conductive transport of heat, pressure gradient, and viscous dissipation. The analysis takes account of the true helical geometry and involves assumptions only in taking the fluid density, specific heat and thermal conductivity of the fluid to be constant, in regarding the fluid to be homogeneous and isotropic, and in simplifying the pressure distribution.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130307
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    Rheology of network forming systems (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 236-240 
    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: Viscosity and dynamic shear measurements are reported on several network forming systems as a function of reaction time and temperature. Phenolic, epoxy and EPDM rubber systems are examined. Rheological data are related to the reaction kinetics of the systems. With these relations overall activation energies, reaction orders and rate constants are interpreted from the data. These compare favorably with results in the literature.Applications of rheological techniques to processing problems of several network forming systems are described, specifically thermoset injection molding and SBR rubber vulcanization.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130312
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    The effect of flake aspect ratio on the flexural properties of mica reinforced plastics (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 139-145 
    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: Two naturally occurring micas, phlogopite and muscovite, were ground and classified according to their average aspect ratios (flake equivalent diameter to thickness ratio). These flakes were then used to reinforce a polystyrene copolymer and a polyester resin. The compression molded test pieces were tested in flexure and the flexural strengths and flexural moduli determined for each aspect ratio. The experimental results indicate a strong dependence of strength and modulus on the flake aspect ratio up to a value of 100-200 for these systems. At high volume fractions, 0.6 to 0.7, high aspect ratio mica composites yielded flexural strengths of 35-45,000 psi with flexural moduli of 10-14 million psi. Notched Izod values were in the range of 0.5-1.4 ft lb per inch of notch. These results were compared with the theoretical treatments of Padawer and Beecher, and Riley.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130210
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    Masthead (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973) 
    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.760130601
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  • 56
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    Investigation of the ductility of rolled polymers (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 422-428 
    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 effect of cold rolling on the mechanical properties of polymers, viz., acetal, nylon 66, poly(vinyl chloride) and polycarbonate has been studied. The yield strength, Young's modulus, and hardness increase with increasing cold work, except for a slight drop in these properties at low values of cold work. The ductility increases with rolling to a maximum and drops with further reduction. At the same time, the tensile strength increases continuously with rolling. This conspicuous occurrence of the increase in ductility with a simultaneous increase in tensile strength for polymers, unlike that in metals, is explained considering the morphological changes produced in polymers upon cold rolling. It is shown that this typical behavior is not due to the unique loading or heating and cooling cycle involved in the rolling process.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130605
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    Solvent crazing of polystyrene and polymethylmethacrylate (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 390-394 
    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 minimum surface strain required to induce crazing in polymethylmethacrylate and polystyrene in the presence of alcohols and n-heptane has been determined at various temperatures by bending strips of the polymers around formers of varying curvature and immersing them in the liquid reagents. For each polymer/liquid system the long-term crazing strain was independent of test temperature except within a single 30°C interval in which it decreased as the test temperature was raised. It was found that this temperature region corresponded to the glass-rubber transition of the given polymer when, after extended periods of immersion it had achieved equilibrium liquid sorption. This suggested that, in the crazing tests, a condition approximating to equilibrium sorption was being established at the craze tip and that crazing occurred on applying small strains in the presence of the liquids because of their plasticising effect.It was found that not only the plasticizing effect of the liquid environment but also the liquid molecule size influenced the crazing strain; the larger-molecule liquids caused lower long-term crazing strains than did the smaller-molecule liquids.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130511
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    Synergism in thermal stabilization of polyvinyl chloride (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 35-39 
    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: Plasticized polyvinyl chloride was thermally stabilized by barium, cadmium, and zinc laurates, epoxidized soybean oil, and monoalkyl diaryl phosphite, and by combinations of these stabilizers. Of 26 possible combinations, 18 showed some improvement, 8 showed useful improvement, 7 showed marked improvement, and 3 systems were outstanding. Of the 26 combinations, 10 showed distinct synergism, based mainly upon combinations of Group II-B metals with Group II-A metals, “secondary” stabilizers, or both. Combinations of Group II-B metals with “secondary” stabilizers were particularly interesting and promising.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130106
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    Mechanical relaxation phenomena in polyimide and poly(2,6-dimethyl-p-phenylene oxide) from 100°K to 700°K (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 51-58 
    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: Existing dynamic mechanical relaxation data on two polymers containing aromatic groups in the backbone chain, viz., polyimide PI, and poly(2,6-dimethyl-p-phenylene oxide), PDMPO, are reviewed and new data bearing on specimen purity and water content are presented. It is demonstrated that three separate relaxation processes are normally present in both polymers in the temperature range from about 100-400°K. The lowest temperature relaxation, designated γ, occurs in the 100-180°K range and is considered to arise from limited rotational oscillation of some phenylene rings about the 1,4 axis. Another relaxation process, designated β arises from the presence of water in the polymer. Its strength increases with increase of water content, its activation energy is about 10-12 kcal/mole, and it occurs in the 180-190°K range at 1 Hz. A higher strength secondary glass relaxation process, designated β*, occurs in the 280-400°K range at usual measuring frequencies (1 Hz to 104 Hz). This relaxation is thought to be associated with the combined reorientational motion, of rings and connecting atoms of the monomer unit in “defect” regions, or regions of poor chain packing. As such, its position is affected by sample history. Both polymers also show a rise in damping in the high temperature region indicative of additional main chain motions. In addition to the above relaxations, PDMPO shows a δ-relaxation below liquid nitrogen temperatures, associated with onset of Me rotation and PI shows an additional small relaxation near 500°K.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760130109
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    Vapor sorption and liquid interactions with glassy polyblends of polystyrene and poly(2,6-dimethyl-1,4-phenylene oxide) (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 81-87 
    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: Polystyrene, poly(phenylene oxide), and solution-cast blends of the parent homopolymers were exposed to normal hexane in the liquid and vapor phase. The kinetics of absorption and desorption, the sorption equilibria, and the kinetics of morphological changes were studied as a function of temperature and blend composition.Absorption kinetics of n-hexane vapor in all blends were largely controlled by polymer relaxations. The sorption rates from the vapor phase varied monotonically with blend composition and increased over a range of four orders of magnitude with increasing poly(phenylene oxide) content. The equilibrium n-hexane content similarly increased monotonically with poly(phenylene oxide) content although the increase was only by a factor of two over the entire range of compositions. These results were interpreted in light of and were completely consistent with earlier findings with pure polystyrene homopolymer.Films immersed in liquid n-hexane produced a white, opaque outer shell surrounding an essentially unaffected central core. The kinetics of this whitening process were much more rapid for each of the homopolymers than the kinetics characterizing morphological changes in the blends. These data suggest that film whitening is caused by crazing in the polystyrene-rich samples and that solvent-induced crystallization is involved in the whitening of the poly (phenylene oxide) rich material.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130202
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    Low temperature transitions in a crosslinked urethaneThis work supported by the U.S. Atomic Energy Commission. (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 120-124 
    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: We have investigated the low temperature transitions in a urethane prepolymer crosslinked with various amines and triols by measuring their dynamic mechanical properties over a temperature range of 25°C to approximately - 190°C. In the formulations studied, a low temperature transition was observed near - 140°C and the transition was shown to be related to the electronic and steric influences of the curing agent structure at the crosslink site. A quantitative relationship was demonstrated between the low temperature transition peak intensity and the polymer's crosslink density. The above relationships were derived from torsion pendulum and solvent swell experimentation.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130207
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    Evaluation of the smoke and flammability characteristics of polymer systems (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 146-152 
    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: Using Oxygen Index and the XP-2 test to measure flammability and smoke characteristics, a broad spectrum of thermoplastic and thermoset polymers, both commercial and experimental, were investigated to elucidate the effect of structure on fire properties.In general, polymers with aliphatic backbones are very flammable, but their tendency to generate smoke is minimal. The addition of flame retardants, especially halogen compounds, while reducing their tendency to burn, increases the evolution of smoke. Halogen-containing polymers are usually non-flammable, with high Oxygen Indices, but display high smoke generation. Polymers containing an aromatic group in the side chain, such as polystyrene, are both highly flammable and high smoke producing. However, polymers with the aromatic group in the main chain, such as polysulfone, polycarbonate and polyphenylene oxide, are intermediate in both Oxygen Index and smoke generation.After investigation of the various test methods available, it is concluded that no one test will be satisfactory to measure the flammability characteristics of polymers and that a combination of methods must be used.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130211
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    Model filler reinforcement studies by small angle X-ray scattering (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 176-186 
    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: Polybutadiene rubbers, filled with polydichlorostyrene or polystyrene latices having spherical diameters of approximately 500Å, were examined by small angle x-ray scattering. The filler latices were examined by x-ray scattering as a function of strain. The sample elongations ranged up to 400 percent. An analysis of the scattering of the polydichlorostyrene filler latices showed that there was deformation of the filler particles up to 25 percent. Such a deformation is not expected on the basis of the mechanical properties of bulk glassy polydichlorostyrene. However, deformation into ellipsoids of revolution is consistent with the x-ray evidence. The deformation of the latices is reasonable.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130303
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    A numerical simulation of the cavity filling process with PVC in injection molding (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 102-112 
    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: Filling cold mold cavities with hot polymer melts at high pressures is of great practical interest. The transport approach to this process of solving the general equations of change with suitable equations of state to describe the flowing material has been largely ignored. No analytic solution is possible, and the non-steady state flow adds a dimension which makes digital computation discouraging because of the core storage and execution time requirements.The mold filled in this simulation is a disk which hot polymer melt enters through a tubular entrance located at the center of the top plate. The tube is 2.54 cm. long and has a radius of 0.24 cm. The plate separation and outer radius of the disk cavity may be varied. A constant pressure applied at the entrance of the tube causes the flow. The cavity walls are kept at various low temperatures. The reported results are for rigid polyvinyl chloride (PVC).The general transport equations, i.e. continuity, momentum, and energy, for a constant density power law fluid are used to solve the flow problem. Convergence to the differential solutions is guaranteed but since a lower limit was imposed on the time increment by the core storage limit of the computer facilities (27K) and long execution times, all results are semiquantitative for the problem as stated.Using the results obtained it is possible to predict “fill times”. The formation of a frozen polymer skin as the cavity fills may be followed via the velocity profiles. The temperature profiles which reflect cooling and the amount of viscous heat generated provide the basis for studying resin thermal degradation effects.Finally, because so much of the total pressure drop is disispated in the entrance tube, and so much viscous heat is generated there, this study indicates that the design of the gate and runner system is perhaps the most important facet of success in mold filling.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130205
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    Strain hardening equation and the prediction of tensile strength of rolled polymers (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 266-272 
    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 number of thermoplastic polymers were tested in tension to investigate their strain hardening behavior. A strain hardening equation has been proposed in terms of the true stress, true strain and two constants σo and m. The three material constants, viz. σo m and the true fracture strain, are shown to be adequate to describe completely the material's nonlinear viscoelastic or the so-called “plastic” behavior. The true stress-strain data for the polymers rolled to varying amounts of cold-work fits the strain hardening plot of the unrolled material. The same strain hardening equation, therefore, applies to rolled materials as well. The procedure for predicting the tensile strength of rolled materials is given.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130405
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    Effects of gamma radiation on the dynamic mechanical and swelling behavior of styrene butadiene block and random copolymers (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 280-286 
    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 structure of a number of styrene-butadiene copolymers were investigated via dynamic mechanical and swelling studies on uncrosslinked and gamma-radiation cross-linked films that had initially been solvent cast from toluene or methyl ethyl ketone. The mechanical behavior of these films before and after crosslinking was found to depend on the material history as well as the chemical structure of the copolymer, in agreement with observations made by other experimental techniques. A simple morphological interpretation was given to the dynamic mechanical spectra as a function of radiation dosage and a limited discussion of the swelling behavior is included.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130407
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    Publisher's message (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 321-321 
    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.760130502
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    Rate of strain effect on the thermal conductivity of a polymer liquid (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 337-341 
    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 effective thermal conductivity of a polymer liquid was measured as a function of strain rate. The polymer liquids studied were three commercial grades of polydimethylsiloxane. The experimental results show a dependence of effective thermal conductivity on strain rate. This dependence is believed due to either the rotation of large clusters of entangled macromolecules, or the orientation of the individual macromolecules, or possibly the combination of both mechanisms simultaneously in shear flow.The effective thermal conductivity, for all three samples studied, increased with increasing strain rate. The rate of increase was found to decrease with increasing temperature.The thermal conductivity measurements were made in an annular axial flow test cell that utilizes a hot wire probe technique. Convection problems were eliminated by proper placement of the temperature measuring section of the wire in the cell.A tentative model was used through which the size of the cluster can be estimated. Once the size of the cluster is obtained, the rotational contribution to the energy transport can be estimated. Initial predictions agree well with the observed phenomena.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760130504
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  • 69
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    Study of the variables affecting pressure drop and temperature rise in blow molding dies (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 372-381 
    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 extrusion head systems for both pipe and blow molding were analyzed theoretically and relationships derived between pressure drop and temperature rise for various materials at different flow rates and die restrictions.Because of the complexity of the geometry involved, the die was segmented into several sections axially and momentum and energy equations for these sections were solved with the help of IBM 360. The floating boundary conditions were used in order to take into account the nature of the flow phenomenon involved.To complement and support this theoretical work, rigid polyvinyl chloride (PVC) bottle compounds were used to obtain extrusion data on a 3½ inch extruder with several different die sizes. A good agreement was found between the predicted versus experimental data. Results showed that temperature rise in the die systems in significant and that neglecting it would result in a gross error in the calculated pressure drop.Based on this work, a simplified version of the theoretical equation was developed to serve as an engineering tool in estimating pressure drop and stock temperature for a given material where extreme accuracy is not essential. Results of the engineering equation which contains several empirical constants correlate well with the data and support the theoretical effort.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130509
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    Theoretical prediction of pressure loss in pressurized plastic containers (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 440-446 
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    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: Relations describing the time dependence of pressure loss in pressurized plastic containers are presented and discussed. These relations are expected to be useful in predicting the shelf life performance of pressurized plastic containers in applications such as aerosol and carbonated beverage containers. The time dependence of pressure loss in pressurized plastic containers is shown to be dependent on at least three independently contributing factors, namely gas absorption, gas permeation, and material viscoelastic characteristics. The influence of these three qualities is shown to be time dependent and expressions are presented which allow the relative importance of each to be assessed in terms of quantities that are conveniently measured in the laboratory. The pitfalls associated with defining quantitatively the effectiveness of a plastic barrier material as predicted by a steady state analysis is discussed. It is shown that such steady state analysis may be extremely misleading and may not necessarily be a measure of a material's time dependent qualities.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130608
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    Tailoring the interface in graphite-reinforced polycarbonate (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 455-461 
    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: Pronounced effects of thermal treatment on the properties of graphite fiber/polycarbonate and glass fiber/polycarbonate composites have been demonstrated and explained. At 20 volume percent loading of random-in-a-plane, discontinuous fibers, both specimen strength and modulus in both fiber systems were found to increase dramatically upon molding above 260-265°C, whereas only the graphite system was further improved by subsequent annealing. In the latter case, property improvement is due to generation of a crystalline innerlayer at the interface, which apparently transfers the stresses more effectively from fiber to fiber. Regardless of the type of fiber, molding at 275°C (slightly above 260-265°C, the melting point of crystalline polycarbonate) results in improved properties due to better wetting of the fibers by the resin. Hot forming of graphite reinforced polycarbonate composites between the molding and annealing steps takes advantage of the higher processability of the unannealed material in addition to providing increased modulus and strength in the final molded article.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130610
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    Polyimides: Effect of molecular structure and cure on thermomechanical behavior (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 447-454 
    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 thermomechanical spectra (∼0.5 → 1 cps) of systematically related polyimides synthesized from four aromatic dianhydrides and eleven aromatic diamines are discussed with respect to structure-property relationships and cure. In displaying two main transitions, Tg and Tβ, most of the polymers behave as amorphous materials such as polymethylmethacrylate. A different mechanism for the relaxations is invoked which involves more intermolecular interaction for those polymers (from pyromellitic dianhydride) which give more complex behavior. Difficulties in obtaining structure-property relationships in the field of high temperature rigid polymers are discussed in terms of defects in molecular structure, the effect of vitrification in freezing out reactions during cure, different chemical reactivities of the reactive precursor polyamic acids, and the effects of thermal reactions which occur in the vicinity of the glass transition regions.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130609
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    Strength of particulate composite (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 469-469 
    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
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130612
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  • 74
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    Masthead (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973) 
    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.760130101
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  • 75
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    Fracture of fiber glass laminates (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 17-28 
    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 applicability of fracture mechanics to the description of initial notch extension under tension in quasi-isotropic fiberglass laminates is tested experimentally. It is found that classical elastic fracture mechanics, without modifications of couple stress effects, as represented in the theory of Muki and Sternberg, is sufficient to describe initial notch extension in prenotched specimens which are sufficiently thick to avoid transplanar bucklings of the specimen under tension. The fracture toughness (KIC) is found to be 15 ksi √in. However, it is noted that in these specimens (0.035 in. thick) transplanar postbuckling deformation becomes pronounced well before fracture, and that different modes of buckling seen in externally notched and internally notched specimens have opposite effects on the apparent fracture toughness of the specimen. It is pointed out that the effect of transplanar buckling on fracture of fiber glass, with its high compliance and high strength, is a potential source of serious problems in design with this material.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130104
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  • 76
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    Solid-state structure of melt blended incompatible polymeric mixtures involving poly(vinyl chloride) (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 46-50 
    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: Poly(vinyl chlorides) having different melt viscosities were melt blended with several different incompatible polymers using a two-roll mill and a Brabender Plasticorder. The properties of the mixtures can be easily reproduced from batch to batch only if the viscosity of the components does not change during the mixing process. Within this limitation, the order of addition of the components during the mixture preparation does not have a significant influence on the mixture properties.The shear storage modulus of the incompatible mixtures in the temperature range between the Tg's of the components varies with the difference in component viscosities at the temperature of mixing. The moduli of these mixtures are compared to moduli calculated using Kerner's equations. Based on this comparison it is concluded that in any incompatible mixture the component having the lower melt viscosity at the temperature of processing tends to form a continuous phase in the mixture. The greater is the viscosity difference, the greater is this tendency. The viscosity of one component relative to the other can be changed by changing the molecular weight of the components and/or the temperature of mixing.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130108
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  • 77
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    The effect of light on some commercially important polymersIssued as NRCC No. 12997. (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 74-77 
    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: Most organic polymers are damaged by exposure to terrestrial sunlight and eventually the useful properties are lost. Once absorbed, radiation in the erythmal region of the solar spectrum has sufficient energy to cause the rupture of polymer chain bonds.It can be difficult to identify the important chromophores in a polymer system and even more difficult to determine precisely what happens to them following electronic excitation. The number of chemical events leading to the mechanical failure of a plastic can be remarkably small although the variety of them is potentially large.Polypropylene is discussed as an example of a thermoplastic which invariably contains small amounts of light-absorbing impurities and which, if unprotected, is highly susceptible to photo-oxidation. Polyethylene terephthalate is used to illustrate a class of polymers which is susceptible to actinic deterioration owing to chromophores in the repeating unit. The primary photochemical reactions occurring in these two systems are described, with improved methods for UV stabilization in mind.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130112
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    Synergistic interaction in zinc/epoxy/phosphite stabilization of polyvinyl chlorideThis paper is taken from a thesis submitted by Robert M. Foss to Lowell Technological Institute in partial fulfillment of the requirements for the degree of Master of Science in Plastics. The work was supported in part by a fellowship from the Plastics, Institute of America. It was presented at the Annual Conference of the Plastics Institute of America, June 21, 1972. (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 96-101 
    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: Zinc laurate was a powerful but short-lived primary stabilizer. Epoxidized soybean oil, catalyzed by a trace of zinc, was a fairly good primary stabilizer. Organic phosphite ester served primarily to prevent premature failure due to zinc; phosphite/zinc mol ratio of 4.5/1 was optimum. These combined effects are consistent with present theories of stabilizer synergism, and also suggest some further possible mechanisms. Practically, the 3-component system offers a low-cost, efficient, non-toxic stabilizer for plasticized polyvinyl chloride.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130204
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  • 79
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    Implications of extensional flows in polymer fabrication processes (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 125-130 
    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: The various types of extensional flows and extensional viscosities are defined and methods of measurement discussed. The role that each of these extensional viscosities plays in various polymer fabrication processes is discussed with examples. Finally, it is shown how engineering analyses of these complex flow fields are conducted using simplified phenomenological equations for the rheological behavior. This approach is recommended for use until such time as tensorially correct, mathematically tractable constitutive equations that are based on molecular theory are available.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130208
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  • 80
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    Masthead (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973) 
    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.760130301
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  • 81
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    Poisson's ratio and the deflection of a viscoelastic plate (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 187-193 
    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 new method for the measurement of the Poisson's Ratio function of the more rigid plastics is described. The deflection of a freely-supported circular plate under uniformly distributed load is combined with modulus data obtained in an independent experiment. The apparatus is described, the validity of the relevant elastic stress-strain formulae are discussed and the results obtained on PMMA and PVC are compared with other published values. It is concluded that this method is at least as accurate as the alternatives, all of which have particular deficiencies, and that it is possibly superior in some respects.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130304
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  • 82
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    Reflectivity of iridescent coextruded multilayered plastic films (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 216-221 
    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: Coextruded plastic films containing 231 alternating layers of polystyrene and polymethylmethacrylate have been made with individual layer thickness in the range of .06-0.1μ. Due to the difference in refractive indices these unique films can be made to reflect portions of the visible spectrum, yielding a highly iridescent appearance.Reflectivity measured on films of known layer thickness distribution correlated with values predicted from optical theory.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130308
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  • 83
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    Masthead (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973) 
    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.760130401
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  • 84
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    Impact reinforcement of poly(vinyl chloride) (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 248-254 
    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: Several theories have been advanced to explain the toughening of glassy plastics by rubbery modifiers. These have been based primarily on studies of high impact polystyrene or ABS systems, where the crazing mechanism has been shown to be most applicable. In the present study, the effects of MBS (methacrylate-butadiene-styrene) impact modifiers on PVC have been studied, utilizing both physical and microscopic techniques. Tensile test results indicate that a primary contribution of the modifier to increased toughness is a lowering of the yield stress of the PVC. Electron microscopic studies and density determinations on strained samples indicate no crazes in these MBS-modified PVC systems. These results suggest that the mechanism of impact reinforcement in PVC is based on the enhancement of localized yielding in the vicinity of the rubbery modifier particles.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130403
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  • 85
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    Heat transfer to flowing thermally softened polymers (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 287-294 
    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: Heat transfer to a flowing thermally softened polymer (polymethylmethacrylate) has been studied. Experimental temperature profiles were determined at various axial lengths. The data are both precise and reproducible. Sizeable viscous dissipation was found to occur. This effect was found to be greater for polymethylmethacrylate than a molten polymer (polyethylene). Cooling as well as heating data were found in this work. The experimentally determined data checked qualitatively with the data computed from a prior analytical solution of the equations of motion and energy.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130408
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  • 86
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    A mathematical model for predicting dynamic behavior of a plasticating extruder (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 346-356 
    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 mathematical model was developed to predict the dynamic behavior of flowrate and melt temperature in a plasticating extruder caused by changes in operating variables such as screw speed, back pressure and barrel temperature. The model has application for on-line computer control of an extrusion process or for simulation purposes off-line. Experimental data for developing the model was obtained from a 2½ in. diameter plasticating extruder producing high impact polystyrene sheet.
    Additional Material: 27 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130506
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  • 87
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    Design of certain fluted mixing sections of extruder screws (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 382-389 
    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 theoretical model is proposed, for certain barrier type fluted mixing sections of extruder screws. Screws with such mixing sections are occasionally used in plasticating extruders. With the aid of this model, these screws can now be quantitatively simulated in the design stage. Specifically the model enables the calculation of pressure change across the section as a function of geometrical configuration of the mixing section and operating conditions.A generalized set of curves, plotted in dimensionless form, for quick manual computation is also given. With its aid, the effect of the design variables on the pressure change is discussed.Finally, mixing section-zones, in reference to the plasticating extrusion theory, and the state of the art of extrusion theory are very briefly discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130510
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  • 88
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    Correlation between uniaxial and shear creep of thermoplastics (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 398-400 
    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: Creep data in uniaxial tension, compression and shear on PVC, PMMA, and PP sheet were used to test analytical correlating procedures. It was shown that shear and uniaxial creep could be closely related using the concept of shear stress and shear strain on octahedral planes. This correlating procedure was only effective if due allowance was made for the different creep response in simple tension and compression for each of these materials. It was also shown that the relationship between the viscoelastic creep moduli and strain ratio, which is stress and time dependent, has the same form as the analogous relationship between the linear elastic constants.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130513
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  • 89
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    Exudation of an antioxidant additive from thin polyethylene films (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 435-439 
    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: Surface microscopy studies have revealed the phase separation and exudation of a phenol type of antioxidant [4,4′-thiobis (3-methyl-6 tert. butyl phenol)] from polyethylene at concentrations of 0.08 percent by weight. The equilibrium solubility of the antioxidant in polyethylene was estimated to be less than 0.01 weight percent at room temperature.About 70 percent of the antioxidant was expelled from a thin polyethylene film after storage for three days at 70°C. Since the initial concentration of the stabilizer is typically 0.10 percent of the polymer by weight, the antioxidant exudation can lead to a serious shortening of the expected life of the polymer. Prediction of lifetime by accelerated aging tests must account for the depletion of the stabilizer by exudation. The life of stabilized samples should be measured at concentrations which do not exceed the solubility limit of the antioxidant in polyethylene at its use temperature.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130607
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  • 90
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    Copolymerization of caprolactam with polyoxybutylene diamine (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 88-95 
    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: Nylon 6-polyoxybutylene block copolymers were prepared by reacting polyoxybutylene diamine with caprolactam in the presence of phosphoric acid. The copolymerization was carried out in a Helicone-type reactor and the effect of time, temperature, and caprolactam concentration on the properties of the products was recorded. Differential Scanning Calorimetry studies of the products suggest the presence of both the ABA and AB types of sequences, where A and B represent nylon 6 and polyether blocks, respectively. Dynamic mechanical measurements of typical copolymers revealed the presence of at least two different nylon moieties. The melt rheology data reflect a general increase in the pseudoplasticity of the copolymer with the increase of the polyether content. Increases of the polyether content in the copolymer result in an increased elongation and a decreased tensile strength and modulus.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130203
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  • 91
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    Procedures for the evaluation of the long term strength of plastics and some results for polyvinyl chloride (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 113-119 
    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 problems associated with the study of failure are reviewed and exemplified by results on two commercial grades of PVC. The whole range of failure phenomena, from crazing to fracture, and the effect of notches on durability is discussed. A test schedule involving minimum experimental effort for the evaluation and comparison of the long term durability of thermoplastic materials is proposed.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130206
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  • 92
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    Comparison between some empirical equations of state for polymers (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 131-138 
    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 commonly used empirical equations of state for polymers are considered: the Spencer-Gilmore equation with two and three adjustable parameters, the Whitaker-Griskey equation, and the Rehage-Breuer equation. Also, a new equation is proposed: the Inverse Volume equation. These equations are evaluated with regard to fitting experimental P-V-T data and agreement with experimental data on isothermal compressibility and thermal expansion coefficient. The adjustable parameters for each equation are determined with the help of Rosenbrock's optimum-seeking technique. Analysis of the residuals on specific volume for a variety of materials suggests that the Spencer-Gilmore equation with three adjustable parameters, the Rehage-Breuer and the Inverse Volume equations yield the smallest and most random residuals and thus the least systematic error. The same three equations mentioned above yield results in good agreement with experimental isothermal compressibility data. However, among all the equations considered in this study, the Inverse Volume equation yields the best agreement with experimental thermal expansion coefficient data. Furthermore, it is the only equation to correctly predict the rise in thermal expansion coefficient with increasing temperature.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130209
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  • 93
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    Physical properties of polymers-an introductory discussion (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 161-175 
    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: Physical characteristics of isolated molecules and bulk polymers are discussed briefly. The broad spectrum of mechanical properties resulting from changes in temperature and experimental time-scale is introduced by first considering the time-independent properties of elastomers under large deformations and then the effect of a progressive decrease in segmental mobility, leading eventually to glassy characteristics. The phenomenological theory of linear viscoelasticity along with time-temperature superposition is outlined, and illustrative data are presented. Finally, phenomena resulting from volumetric relaxation processes are considered briefly.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130302
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  • 94
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    Chlorinated polyethylene modification of blends derived from waste plastics Part I: Mechanical behavior (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 202-208 
    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: Recycling of waste plastics as a blend of generic types is attractive since a difficult separations problem is avoided. However, blends of incompatible polymers are frequently very brittle and cannot be considered for many applications. Additives which modify the blend to give it ductility may provide a solution to this problem. Chlorinated polyethylene (CPE) made by a slurry process has been suggested for this application by Schramm and Blanchard. Further documentation of the effectiveness of this approach is given here. Addition of CPE to such a blend generally increases the elongation at break and the energy to break very dramatically with ordinarily some loss in strength and modulus. This approach works most effectively in blends of high polyethylene and poly(vinyl chloride) content. Three grades of CPE were studied here which revealed that the specific structure of the CPE molecule is a factor. The effectiveness of CPE for blend modification is believed to derive from the graded molecular structure acquired during chlorination.
    Additional Material: 12 Ill.
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    URL: http://dx.doi.org/10.1002/pen.760130306
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    The application of melt elasticity to polymer processing (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 227-230 
    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 present state of knowledge of polymer melt elasticity is reviewed together with consideration of the problems that elastic effects cause in polymer processing systems. Two examples of the useful application of melt elasticity are presented, one in melt extrusion the other in polymer melt mixing.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130310
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  • 96
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    Electronic Resource
    An introduction to blood compatible polymer surfaces for use in artificial internal organsPresented in part at the 68th National Meeting, American Institute of Chemical Engineers, Houston, Texas, February 28-March 4, 1971. (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 241-247 
    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: While the body is a hostile environment for all types of polymers, an even more serious problem is that of thrombus formation induced by all foreign surfaces, including polymeric surfaces. This is a still largely unsolved problem which hinders the development of artificial internal organs. The thromboresistant materials presently proposed and used in artificial organs include heparinized surfaces and materials found to be thromboresistant in certain implantation cites. In this article tissue-polymer interactions are first discussed and then followed by a discussion of blood-polymer interactions. The mechanism of thrombus formation is presented and some of the possible interactions of blood with surfaces are suggested. Representative nonthrombogenic and thromboresistant materials are discussed.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130402
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  • 97
    Electronic Resource
    Electronic Resource
    Flow behavior of well characterized polyethylene melts (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 273-279 
    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 careful characterization and rheological study of low density polyethylene (LDPE) reveals that long-chain branching (LCB) plays a decisive role. At constant molecular weight (M̄w) higher LCB reduces the Newtonian viscosity ηo and the shear sensitivity, increases the activation energy Eo, and finally delays transition to pseudoplastic flow to higher shear rates and the onset of melt fracture to higher shear stresses (τd). The flow parameters ηo, \documentclass{article}\pagestyle{empty}\begin{document}$ \dot \gamma _{cr} $\end{document}cr, τd, and the derived flow relaxation times are uniquely correlatable by means of a modified molecular weight (gM̄w) incorporating the LCB effect. High density polyethylene are less shear sensitive than their low-density counterparts, have a lower activation energy, fracture at higher shear stress levels and cannot be regarded as branchless LDPE's.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130406
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  • 98
    Electronic Resource
    Electronic Resource
    Masthead (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973) 
    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.760130501
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  • 99
    Electronic Resource
    Electronic Resource
    Yielding of polycarbonate and polysulfone in creep and stress-strain (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 300-307 
    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 modified Eyring rate expression based on an asymmetrical potential energy barrier is used to predict the onset of plastic yield in glassy polymers. Equations for the prediction of plastic yield delay times in creep and yield stresses in constant rate of strain testing are developed and compared to experimental data for samples of polycarbonate and polysulfone with various thermal histories. The two equations accurately fit the experimental results for a suitable choice of parameters. Parameters from the creep data can be used to predict yield stress values in constant rate of strain testing. Variation in simple thermal history changes the model parameters in a way that is qualitatively accounted for from a physical interpretation of the constants.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130410
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  • 100
    Electronic Resource
    Electronic Resource
    Differential scanning calorimetry of the epoxy cure reaction (1973)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 13 (1973), S. 365-371 
    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: From a review of the literature it is shown that kinetics from programmed heating rate experiments are often in serious disagreement with published isothermal data. In every case, including the present, the dynamic kinetic parameters measured on epoxies are significantly larger than the isothermal. Use of a dynamic rate equation provides good agreement between the two experiments. It is also shown that the Kissinger method is correct when applied to DSC of epoxies.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760130508
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