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  • 1980-1984
  • 1965-1969  (2,111)
  • 1968  (2,111)
  • Polymer and Materials Science  (1,720)
  • Life and Medical Sciences  (379)
  • Kidney  (12)
  • Nuclear reactions
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  • 1980-1984
  • 1965-1969  (2,111)
Year
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Beziehung zwischen chronisch-toxischer Knochenschädigung und Fremdmetallbindung an Serum-Proteine (1968)
    Springer
    Archives of toxicology 23 (1968), S. 245-249 
    Details
    ISSN: 1432-0738
    Keywords: Bone ; Strontium poisoning ; Parathormone ; Kidney ; Knochen ; Strontiumvergiftung ; Parathormon ; Niere
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Restitution des strontiumgeschädigten Skelets wachsender Sprague Dawley Ratten ist von einem Anstieg der dialysablen Strontium- und Calciumfraktion des Serums begleitet. Die Ergebnisse legen eine Beeinflussung der renalen Manipulation von Kationen bei Knochenschädigungen durch Fremdmetalle nahe.
    Notes: Summary Restitution of skeletal damage caused by strontium in growing Sprague Dawley rats is accompanied by an increase in the dialysable serum fractions of strontium and calcium. The results suggest that the renal manipulation of cations is influenced in bone lesions caused by foreign metals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00577404
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  • 2
    Electronic Resource
    Electronic Resource
    Die Harnstoff- und Elektrolytkonzentrationen im Nierenmarkgewebe nach zweitägiger Infusion hypertoner Harnstoff- und NaCl-Lösungen (1968)
    Springer
    Pflügers Archiv 301 (1968), S. 270-279 
    Details
    ISSN: 1432-2013
    Keywords: Kidney ; Concentration ; Infusion ; Urea ; Electrolytes ; Niere ; Konzentrierung ; Infusion ; Harnstoff ; Elektrolyte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Um die gegenseitige Beeinflussung von Harnstoff und NaCl bei der Bildung eines konzentrierten Harns zu untersuchen, werden Ratten 2 Tage lang NaCl-Lösungen mit wechselndem Harnstoffgehalt infundiert. Sodann werden der Harn sowie das Gewebe der Nierenrinde, des äußeren Marks und des inneren Marks auf ihren Gehalt an Kalium, Natrium und Harnstoff analysiert. Es wird gefunden, daß die Konzentrierfähigkeit der Rattenniere unter diesen Versuchsbedingungen für NaCl bei gleichzeitiger Zufuhr von Harnstoff geringer wird. In der Niere steigen NaCl und Harnstoffkonzentrationen unter allen Infusionsbedingungen von der Nierenrinde zur Nierenpapille hin an. Bei Infusion reiner NaCl-Lösungen entsprechen die NaCl- und Harnstoffkonzentrationen im Harn denen in der Papille. Bei Infusion von harnstoffhaltigen NaCl-Lösungen sind im Harn die NaCl-Konzentrationen höher und die Harnstoffkonzentrationen niedriger als im Papillengewebe. Diese Ergebnisse schließen aus, daß die hohen Harnstoffkonzentrationen im Nierenmarkgewebe durch einfache Diffusion des Harnstoffes aus den Sammelrohren in das Nierenmarkgewebe zustande kommen. Es wird die Möglichkeit diskutiert, daß die Harnstoffkonzentrierung unter den hier wiedergegebenen Versuchsbedingungen durch Gegenstromdiffusion in dem Vasa recta-System verursacht wird. Der Konzentriereffekt hierfür könnte durch einen Wasserfluß aufgrund osmotischer Kräfte von dem Blutgefäßsystem in die Henleschen Schleifen zustande kommen, wenn der Harn in den Henleschen Schleifen durch Aufnahme von NaCl, das aus den Sammelrohren stammt, hyperton wird.
    Notes: Summary To investigate the mutual interdependence of urea and sodium in producing concentrated urine, solutions of different concentrations of sodium and urea were infused into the stomach of rats. After two days' infusion, the urine and tissues from the different zones of the kidneys were analysed for sodium, potassium and urea content. It was found that the efficiency of the rat kidney in producing urine with high sodium content was diminished if urea was infused together with the sodium chloride. Under all conditions sodium and urea concentrations increased from the cortex to the papilla of the kidneys. When pure sodium chloride solutions were infused, sodium and urea concentrations in the urine were nearly equal to the corresponding concentrations in the papilla. Infusion of solutions containing NaCl and urea caused production of urine with a higher sodium concentration and lower urea concentration than in the papilla. These results show that the high concentration of urea in the medulla of the kidney does not arise by passives diffusion of urea from the collecting ducts into the medullary tissue. The possibility that the concentration of urea in the inner medulla is produced by counter current diffusion of urea in the vasa recta is discussed. The concentration effect necessary for this counter current multiplication could be created by an osmotic flow of water from the vasa recta into loops of Henle, if the urine in the loops becomes hypertonic by taking up sodium chloride from the collecting ducts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00363774
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  • 3
    Electronic Resource
    Electronic Resource
    Wirkung von Aldosteron auf die Natrium-und Wasserresorption im proximalen Tubulus bei chronischer Kochsalzbelastung (1968)
    Springer
    Pflügers Archiv 300 (1968), S. 148-160 
    Details
    ISSN: 1432-2013
    Keywords: Kidney ; Aldosterone ; Tubular Sodium Reabsorption ; Proximal Tubule ; Sodium Chloride Loading ; Niere ; Aldosteron ; tubuläre Natriumresorption ; proximaler Tubulus ; Natriumchloridbelastung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Ratten erhielten 4 Wochen lang isotone Kochsalzlösung als Trinkflüssigkeit. Glomerulumfiltrat und Passagezeit von Lissamin-Grün im proximalen Tubulus blieben unverändert. Die spezifische Resorptionskapazität des Tubulusepithels — gemessen mit der „gespaltenen-Tropfen-Methode“ — nahm signifikant ab. Daraus ergab sich eine Verminderung der fraktionellen Natrium-und Wasserresorption im proximalen Tubulus von 51 auf 38% der gefilterten Menge. Die Na+-Ausscheidung stieg von 0,06 (Kontrollen) auf 1,25% der gefilterten Menge. Diese Veränderungen waren rückgängig zu machen durch Injektion von d-Aldosteron. Durch Bestimmung des TF/P-Inulin-Quotienten am Ende des proximalen Konvolutes wurden die Ergebnisse bestätigt. Es wird angenommen, daß die Resorptionshemmung im proximalen Tubulus bei chronischer Kochsalzbelastung durch verminderte Sekretion von Mineralocorticoiden bedingt und letzten Endes Ursache der vermehrten Na+-Ausscheidung ist. Ein Teil der proximalen Resorptionshemmung wird anscheinend in weiter distal gelegenen Nephron-Abschnitten kompensiert.
    Notes: Summary Rats were kept on isotonic saline as drinking fluid for a period of 4 weeks. Glomerular filtration rate and proximal transit time of Lissamine green remained unchanged. The intrinsic reabsorptive capacity of the proximal tubular epithelium—measured by the “shrinking-droplet-method”—decreased significantly. As a result, fractional proximal reabsorption of sodium and water decreased from 51 to 38 per cent of the filtered load. Sodium excretion rose from 0.06 (controls) to 1,25 per cent of the filtered load. These changes were reversible by injection of d-aldosterone. The results were confirmed by measuring the TF/P ratio of inulin at the end of the proximal convolution. The results indicate that in rats chronically loaded with salt, the inhibition of fractional proximal reabsorption is due to a decreased secretion of mineralocorticoids, and is the cause of the higher sodium excretion. Apparently, the decreased proximal reabsorption is partly compensated in more distal parts of the nephron.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00362546
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  • 4
    Electronic Resource
    Electronic Resource
    Die Konzentrierfähigkeit der Säugetierniere für Elektrolyte und Harnstoff bei Variation der Plasmaharnstoffkonzentration durch ämodialyse (1968)
    Springer
    Pflügers Archiv 301 (1968), S. 259-269 
    Details
    ISSN: 1432-2013
    Keywords: Kidney ; Concentration ; Dialysis ; Urea ; Electrolytes ; Niere ; Konzentrierung ; Dialyse ; Harnstoff ; Elektrolyte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Um den Einfluß des Plasmaharnstoffspiegels auf die Konzentrierfähigkeit der Niere zu untersuchen, wird der Blutkreislauf von Ratten an eine Dialysiervorrichtung angeschlossen und der Harnstoffspiegel des Blutes für 3 Std durch Dialyse gegen eine harnstoffreie Spüllösung gesenkt. Gleichzeitig wird der Harnfluß der Tiere durch eine Regelanordnung konstant gehalten. Die Regelung wird dadurch erreicht, daß dem Blutkreislauf bei zu hohem Harnfluß automatisch Flüssigkeit entzogen und bei zu niedrigem Harnfluß Flüssigkeit zugeführt wird. Es wird gefunden, daß die Harnstoffkonzentrationen im Harn linear mit dem Plasmaharnstoffspiegel abfallen bzw. ansteigen. Die Summe der Elektrolytkonzentrationen fällt dagegen mit dem Plasmaharnstoffspiegel nur wenig ab. Falls ein völliger Harnstoffentzug möglich wäre, würde auch dann noch eine Konzentrierung der Elektrolyte auf mehr als doppelt isoton möglich sein. Die Ergebnisse der Untersuchung lassen sich am einfachsten mit der Annahme interpretieren, daß in der Niere der Ratte zwei unterschiedlich arbeitende Konzentrierungsmechanismen wirksam sind, von denen der eine im wesentlichen Elektrolyte, der andere im wesentlichen Harnstoff konzentriert. Der Konzentrierungsmechanismus für Elektrolyte könnte im äußeren Mark, der für Harnstoff im inneren Mark lokalisiert sein.
    Notes: Summary To investigate the influence of plasma urea levels on the concentrating power of the kidney, the blood circulation of rats was connected to a dialyser; with dialysis against a urea-free cleaning solution, the urea level of the blood was lowered for three hours. During this, the urine flow of the animals was kept constant by a regulating arrangement. This control was achieved by removing fluid from the blood circulation in the case of too high urine flow and by putting in fluid in the case of too low urine flow. It was found that the concentration of urea in the urine had a direct linear relationship with the plasma urea level. The total electrolyte concentration fell only slightly compared to the plasma urea level falls. If the urea could have been completely removed, high concentrating of the electrolyte, to more than double isotonic, would still have been possible. The simplest way to interpret the results of this research is by the hypothesis that two different concentrating mechanisms are at work in the rat kidney, the one essentially concentrating electrolytes, and the other principally urea. The concentrating mechanism for electrolytes could be localised in the outer medulla, and for urea in the inner medulla.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00363773
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  • 5
    Electronic Resource
    Electronic Resource
    Mikropunktionsuntersuchung am distalen Tubulus beim Goldblatt-Hochdruck der Ratte (1968)
    Springer
    Pflügers Archiv 304 (1968), S. 336-350 
    Details
    ISSN: 1432-2013
    Keywords: Kidney ; Experimental Hypertension ; Distal Tubular Sodium Reabsorption ; Distal Osmolality ; Tubular Potassium Secretion ; Niere ; experimenteller Hochdruck ; distale Natrium resorption ; distale Osmolalität ; tubuläre Kaliumsekretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Vier Wochen nach Klammerung einer Nierenarterie wurde die Funktion des distalen Tubulus untersucht. In der ungeklammerten, unter dem hohen Blutdruck stehenden Niere blieb die Tubulusflüssigkeit bis 90% distaler Tubuluslänge hypoton. Dies wird auf eine erhöhten Flüssigkeitseinstrom aus der Henleschen Schleife zurückgeführt; eine verminderte Wasserpermeabilität des distalen Tubulus konnte nicht nachgewiesen werden. In der geklammerten Niere war mit Ausnahme des frühdistalen Abschnittes die Natriumkonzentration on jeder Stelle des distalen Konvolutes signifikant höher als in der ungeklammerten Niere und in Kontrollnieren. Auch fehlte im distalen Tubulus der geklammerten Niere eine Nettokaliumsekretion. die distale Gleichgewichtskonzentration für Natrium war auf der geklammerten Seite erhöht, auf der ungeklammerten Seite normal. Der isotone Natriumausstrom (Methode des gespaltenen Tropfens) war in der geklammerten Niere vermindert, in der ungeklammerten Niere erhöht. Die frühdistale Harnstoffkonzentration war in der ungeklammerten Niere gegenüber der geklammerten Niere und Nieren von Kontrollratten erniedrigt. Spätdistal war TF/P-Harnstoff in beiden Nieren gleich. Beide Nieren hatten ein normales Glomerulumfiltrat und normale tubuläre Passagezeiten mit Ausnahme einer verkürzten Schleifenzeit in der ungeklammerten Niere. Die Befunde werden dahingehend interpretiert, daß der aktive Natriumtransport im distalen Tubulus der beiden Nieren voneinander verschieden ist, möglicherweise infolge des unterschiedlichen Reningehaltes der beiden Nieren.
    Notes: Summary Four weeks after constricting one renal artery distal tubular function was studied using the micropuncture technique. In the untouched kidney tubular fluid remained hypotonic up to 90% distal tubular length. We believe this to be the result of the high inflow of tubular fluid from Henle's loop. A reduced permeability for water could not be demonstrated. Except for the early part of the distal tubule there was a marked increase in sodium concentration in the clamped kidney as compared to values obtained in the untouched one and in kindneys of control animals. In addition no potassium secretion could be observed in the clamped kidney. The distal steadystate concentration for sodium was increased in the clamped kidney and normal in the untouched one. Reabsorptive half-time, measured by the split droplet technique, was prolonged in the clamped kidney and shortened in the untouched one. Early distal urea concentration was lower in the untouched kidney than in the clamped one and in control kidneys, while at the end of the distal tubule urea concentrations did not differ significantly. Both kidneys had normal glomerular filtration rates and proximal tubular transit times, whereas a shortened transit time through Henle's loop of the untouched kidney was found. The results indicate that active sodium transport in the distal tubule of the clamped kidney differs from that of the untouched one, possibly due to the different renin concentration in both kidneys.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00587709
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  • 6
    Electronic Resource
    Electronic Resource
    Licht-und elektronenmikroskopische Untersuchungen am proximalen Tubuluskonvolut der Rattenniere nach intraluminaler Ölinjektion (1968)
    Springer
    Pflügers Archiv 302 (1968), S. 149-165 
    Details
    ISSN: 1432-2013
    Keywords: Tubules ; Kidney ; Intraluminal Oil Injection ; Ultrastructure of Kidney ; Proximales Tubuluskonvolut ; Rattenniere ; intraluminale Ölinjektion ; Ultrastruktur der Niere
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Light- and electronmicroscopic evaluation of proximal convolutions of the rat kidney were made following injection with either mineral oil or castor oil. The following observations were made: 1. Injection of mineral oil does not result in a complete blockade of the tubular lumen and leads to morphological lesions of epithelial cells. 2. Injection of the more viscous castor oil, in contrast, leads to a dilatation of the tubular lumen and a compression of the brush border of proximal tubular cells. Thus a better blockade of longitudinal flow is achieved. A toxic effect of castor oil on the tubular epithelium could not be detected. Mechanical lesions, similar to those observed after mineral oil injection, were less frequent. They consisted in a penetration of oil into the cells, perhaps as consequence of the tubular dilatation. 3. In oil-injected proximal tubular segments the following cytologic phenomena were observed: a) a cessation of the normal pinocytosis, which is induced in the presence of tubular fluid, b) simultaneously the “large resorption vacuoles” disappear, indicating that they originate from confluence of pinocytotic vesicles, c) in dilated tubules protein resorption vacuoles are found to have ruptured towards the tubular lumen suggesting a high hydrostatic pressure within the vacuoles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00586867
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  • 7
    Electronic Resource
    Electronic Resource
    Tubuläre Wasser- und Substanzbewegungen infolge artifizieller transcellulärer osmotischer Gradienten bei Rana ridibunda (1968)
    Springer
    Pflügers Archiv 303 (1968), S. 249-261 
    Details
    ISSN: 1432-2013
    Keywords: Kidney ; Fluxes ; Osmotic Gradients ; Niere ; Flüssigkeits-Substanzbewegungen ; osmotische Gradienten
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Durch artifizielle osmotische Druckdifferenzen von 150 mOsmol/l zwischen Lumen- und Blutseite der Tubulusepithelien von Rana ridibunda wird Flüssigkeit im Richtungssinne der Reabsorption oder — in geringerem Maße — der Sekretion längs des osmotischen Gradienten bewegt. Na+ wird in jedem Fall „trocken” reabsorbiert. Bei mit Furosemid blockiertem aktiven Na+-Transport läuft isoton Flüssigkeit längs des osmotischen Gradienten aus dem Tubuluslumen in das blutseitige Medium. Bei umgekehrt gerichtetem Gradienten wird das Filtrat so verändert, als ob es durch Einstrom reinen Wassers verdünnt würde. Die Tubulusepithelien verhalten sich so, als besäßen sie — im Zustand des blockierten aktiven Na+-Transportes — ein „Rückschlagventil” für Na+. Wenn der osmotische Gradient so gerichtet ist, daß Wasser oder Flüssigkeit aus dem Lumen in das blutseitige Medium läuft, dann kommt es bei umgekehrt gerichtetem Na+-Konzentrationsgradienten nicht zum Einstrom von Na+ in das Tubuluslumen. Die Na+-Harnkonzentration sinkt beträchtlich unter die des Perfusates, was als Ausdruck einer Na+-Reabsorption gegen den Konzentrationsgradienten gedeutet wird. Bei Blockierung des Na+-Transportes durch Furosemid kommt es wiederum zum Einstrom reinen Wassers in die Tubuluslumina. Die Versuche mit durch Furosemid blockiertem Na+-Transportmechanismus sind beweisend, daß die Tubuli für Na+ im Richtungssinne der Sekretion impermeabel sind. Die „Verdünnung” des Tubulusinhaltes durch einen osmotischen Gradienten, der Wasser in die Tubuli hineinlaufen läßt, kommt also nicht durch ein Überwiegen der Reabsorption über die „Sekretion” zustande. Wird statt des leicht penetrierenden Na-Chlorids das schwer penetrierende Natriumcyclohexansulfamat angeboten, dann wird absolut gegenüber den Versuchen mit Na-Chlorid weniger Na+ transportiert. Im übrigen zeigen die Nieren jedoch das gleiche Verhalten wie bei Angebot von Na-Chlorid.
    Notes: Summary Osmotic gradients of 150 mosmol/l between intratubular fluid and blood in the kidney of Rana ridibunda induce a fluid movement down the osmotic gradient which is stronger into the tubule than out of it. In either case Na+ is reabsorbed “dry”. If the active Na+-transport is blocked by Furosemid an osmotically downhill movement of isotonic fluid out of the tubule obtains. Reversal of the osmotic gradient induces a reversal of flow but the inward moving fluid is diluted. The tubular cells seem to inhibit the backwash of Na+. If the osmotic gradient induces an outflow of fluid out of the tubule no influx of Na+ occurs even in the presence of a concentration gradient for Na+ in the opposite direction. The Na+-concentration in the urine falls considerably below that of the perfusion fluid. This finding indicates Na+-reabsorption against a concentration gradient. Upon blocking of the Na+-transport by Furosemid water enters the tubules. The results of the experiments in which the Na+-transport was blocked by Furosemid prove that the tubules are impermeable for Na+ in the direction of secretion. The “dilution” of the tubular fluid as a result of an osmotic gradient which induces an influx of water isnot due to a reabsorption outbalancing “secretion”. If instead of the easily penetrating NaCl the slowly penetrating Na+-cyclohexanesulphamate is used, less Na+ is transported. However, in every other respect the results obtained are similar to those described above.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01890904
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  • 8
    Electronic Resource
    Electronic Resource
    Natrium- und Wasserresorption in den verschiedenen Abschnitten des Nephrons beim experimentellen renalen Hochdruck der Ratte (1968)
    Springer
    Pflügers Archiv 304 (1968), S. 322-335 
    Details
    ISSN: 1432-2013
    Keywords: Kidney ; Experimental Hypertension ; Tubular Sodium Reabsorption ; Tubular Water Reabsorption ; Henle's Loop ; Niere ; experimenteller Hochdruck ; tubuläre Natriumresorption ; tubuläre Wasserresorption ; Henlesche Schleife
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 4 Wochen nach Klammerung einer Nierenarterie war der Perfusionsdruck der geklammerten Niere normal, während der arterielle Mitteldruck auf 188 mm Hg angestiegen war. Die Ausscheidung von Natrium und Wasser im Harn der geklammerten Niere war normal, im Harn der ungeklammerten Niere erheblich höher als normal. Glomerulumfiltrat (pro g Niere), intratubulärer Druck, Tubulusweite, Passagezeit von Lissamingrün und die fraktionelle Resorption von Natrium und Wasser waren im proximalen Tubulus sowohl in der geklammerten wie in der ungeklammerten Niere normal. In der ungeklammerten Niere war die Passagezeit durch die Henlesche Schleife stark verkürzt und die Resorption von Natrium und Wasser in der Schleife erheblich vermindert. Diese Veränderungen — obwohl zum Teil kompensiert durch vermehrte Resorption im distalen Tubulus und im Sammelrohr — sind verantwortlich für die höhere Wasser- und Natriumausscheidung der ungeklammerten Niere. Die Ursache ist wahrscheinlich eine stärkere Durchblutung des Nierenmarkes. Im Nephron der geklammerten Niere war die fraktionelle Natrium- und Wasserresorption nicht signifikant von normalen Werten verschieden mit der Ausnahme einer niedrigeren Natriumresorption im distalen Tubulus und einer höheren Natriumresorption im Sammelrohr. Der Natrium-Transport im distalen Tubulus ist anscheinend gestört; TF/P−Na+ betrug im Mittel 0,6 bis zum Ende des distalen Tubulus. Die Ergebnisse können die unterschiedliche Harnausscheidung erklären, die beim Hypertoniker mit einseitiger Nierenarterienstenose beobachtet wird (Howard-Test).
    Notes: Summary Four weeks after clamping one renal artery, the perfusion pressure of the clamped kidney was normal whereas the mean arterial pressure had increased to 188 mm Hg. Urinary excretion of sodium and water of the clamped kidney had not changed while that of the untouched kidney increased considerably. Glomerular filtration rate (per g kidney), intratubular pressure, tubular diameter, transit time of Lissamine green and fractional sodium and water reabsorption of the proximal tubule were normal in both the clamped and the untouched kidney. In the untouched kidney, the transit time through Henle's loop was shortened and the sodium and water reabsorption in it was significantly reduced. These changes, although partly compensated by higher reabsorption in the distal tubule and collecting duct, are responsible for the increased sodium and water excretion of the untouched kidney. They are probably due to an increased medullary blood flow. In the clamped kidney, fractional sodium and water reabsorption of the whole nephron did not differ significantly from normal values. However, sodium reabsorption was lower in the distal tubule and higher in the collecting duct. Sodium transport in the distal tubule seemed to be impaired; throughout its length sodium TF/P ratio averaged 0.6. These results may explain the different urinary excretion found in human hypertension following unilateral renal artery stenosis (Howard-Test).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00587708
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  • 9
    Electronic Resource
    Electronic Resource
    Passage of plasma through the kidney studied by external counting and autoradiography (1968)
    Springer
    Pflügers Archiv 305 (1968), S. 96-104 
    Details
    ISSN: 1432-2013
    Keywords: Blood Circulation Time ; Kidney ; Plasma ; Radioautography ; Radioisotope Dilution Technique ; Regional Blood Flow ; Mittlere Kreislaufzeit ; Niere ; Plasma ; Autoradiographie ; Isotopenverdünnungstechnik ; Regionale Nierendurchblutung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary At different times after injection into the renal artery of131I-albumin, the distribution of the tracer in kidneys of the rabbit and the dog was illustrated by a series of autoradiograms. In order to determine the mean circulation time for albumin in the kidney, the radioactivity over the kidney was simultaneously registered by external monitoring. A short mean circulation time was measured for albumin (plasma) passing cortex, and a longer one for that fraction of the albumin that passed through medulla, papillae, and capsule. The investigation rendered probable that the mean circulation time for blood through the kidney determined by the external technique applies to blood passing cortex. The circulation times for blood through medulla, papillae, and capsule are not included in the calculation of the mean circulation time.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00586398
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  • 10
    Electronic Resource
    Electronic Resource
    Zum extrahepatischen Stoffwechsel von Aldosteron (1968)
    Springer
    Clinical and experimental medicine 146 (1968), S. 336-345 
    Details
    ISSN: 1591-9528
    Keywords: Aldosterone ; Kidney ; Man ; Aldosteron ; Niere ; Mensch
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Auf Grund eines Vergleiches der Verhältnisse von 1,2-3HTetrahydroaldosteronglucuronid zu 1,2-3H-18-Aldosteronglucuronid im Plasma von drei Normalpersonen und zwei nephrektomierten Patienten nach einer Injektion von 1,2-3H-Aldosteron haben wir folgende Schlüsse in Betracht gezogen: 1. Das im Blutplasma vorhandene 1,2-3H-18-Aldosteronglucuronid wird nur glomerular filtriert. 2. Die renale Clearance von 18-Aldosteronglucuronid, die etwa das Fünffache der Inulinclearance beträgt [13, 15], mu\ zu vier Fünfteln auf Bildung von 18-Aldosteronglucuronid durch die proximalen [15] Tubuluszellen zurückgeführt werden. 3. Das Ausma\ der renalen Bildung von 18-Aldosteronglucuronid liegt in einer Grö\enordnung von 80% der Gesamtmenge 18-Aldosteronglucuronid im 24 StdUrin.
    Notes: Summary After an intravenous injection of 1,2-3H-aldosterone the ratios of 1,23H-tetrahydroaldosterone glucuronide to 1,2-3H-aldosterone glucuronide in the blood plasma of three normal and two nephrectomized persons were compared. In the three normal persons the ratios were of the same magnitude as in the two nephrectomized persons. On the basis of glomerular filtration of tetrahydroaldosterone glucuronide, as previously demonstrated by renal clearance studies in man [13, 15] and stop flow experiments in dogs [6], we made the following deductions: 1. 18aldosterone glucuronide in blood plasma is only filtered in the glomerulum. 2. The renal clearance of 18-aldosterone glucuronide, as investigated during aldosterone infusion in man [13, 15], therefore must be explained by glomerular filtration of only one fifth and by formation of four fifth of 18-aldosterone glucuronide by proximal [15] tubular cells. 3. This means that about 80% of 18-aldosterone glucuronide excreted in urine is formed by the kidneys.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02045932
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  • 11
    Electronic Resource
    Electronic Resource
    Zum extrahepatischen Stoffwechsel von Aldosteron (1968)
    Springer
    Clinical and experimental medicine 145 (1968), S. 270-277 
    Details
    ISSN: 1591-9528
    Keywords: Aldosterone ; Kidney ; Stop flow dog ; Aldosteron ; Niere ; Stop flow-Hund
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Mit Stop flow-Versuchen an Hunden konnten wir nach Infusion von 1,2-3H-18-Aldosteronglucuronid im Gegensatz zur Infusion von freiem 1,2-3H-Aldosteron keine proximale Sekretion von 1,2-3H-18-Aldosteronglucuronid nachweisen. Daraus kann geschlossen werden, daß in Hundenieren die proximalen Tubuluszellen wohl 18-Aldosteronglucuronid aus Aldosteron bilden und an das Tubuluslumen abgeben, während im Nierenarterienblut vorhandenes 18-Aldosteronglucuronid nur glomerulär filtriert und ausgeschieden wird.
    Notes: Summary In stop flow experiments during infusion of 1,2-3H-18-aldosterone glucuronide there was no proximal tubular secretion of this metabolite in contrary to experiments during infusion of 1,2-3H-aldosterone. The discrepancy must be explained by formation of 1,2-3H-aldosterone glucuronide out of3H-aldosterone in proximal tubular cells, while the 1,2-3H-18-aldosterone glucuronide in the plasma of the renal artery blood is only filtered in the glomerulum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02044618
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  • 12
    Electronic Resource
    Electronic Resource
    Thermodynamic interactions of branched polyethylene in polar and nonpolar systems (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 789-803 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The thermodynamic properties of polymer solutions are frequently described in terms of the Flory-Huggins equation. This equation includes a parameter χ, which depends upon the intermolecular forces acting between the molecules in a solution. The experimental determination of χ was performed by an improved microtechnique and extended to a wide range of polar and nonpolar diluents of polyethylene. Careful correlations are prescribed for calculating χ from pure-component properties; they are based on an extension of the Hildebrand-Scatchard theory of solutions and on the theory of intermolecular forces. Polar (τ) and nonpolar (δ) solubility parameters are presented for a variety of solvents. For polyethylene - nonpolar solvent systems we have emphasized the factor deciding the sign of heat of mixing, while for polyethylene-polar solvent systems we have determined the contribution of dipole-induced dipole interactions ψ (δτ) in interchange-energy density B and, hence, χ.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1968.070120416
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  • 13
    Electronic Resource
    Electronic Resource
    Determination of polyolefin film properties from refractive index measurements. II. Birefringence (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 903-914 
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    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The use of refractive index data for studying changes in oriented polyolefin films has been demonstrated. Application of this technique to oriented polypropylene and polyethylene films showed that the birefringence is a linear function of the refractive index in the direction of maximum orientation. By utilizing refractive index, density, and crystallinity data the crystalline refractive indices nc and (na + nb)/2 and polarizabilities α∥ and α⊥ could be estimated for polypropylene and polyethylene.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1968.070120424
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  • 14
    Electronic Resource
    Electronic Resource
    Comment on the novel parameter of polymer structure suggested by W. S. Bahary (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 973-974 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1968.070120430
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  • 15
    Electronic Resource
    Electronic Resource
    Influence of molecular weight on some properties of poly(vinyl chloride) (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 1119-1136 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Several fractions obtained from a large-scale fractionation and several unfractionated PVC polymers and blends have been processed both as rigid and plasticized compounds. The latter have been studied by stress-strain, creep, and recovery tests. The recoverable character of the creep results show that a relatively stable network must be present in the samples. The crosslink density is little influenced by molecular weight, as shown by the modulus and compliance results. On the contrary, the ultimate tensile properties depend strongly on molecular weight, which is interpreted as evidence that the stability of the crosslinks increases with increasing chain length of the polymers.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1968.070120511
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  • 16
    Electronic Resource
    Electronic Resource
    Growth, morphology, and reinforcement potential of low molecular weight crystals in amorphous polymeric matrices (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 1151-1165 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The technique of in situ crystallization of low molecular weight organic compounds from amorphous polymers was evaluated as a method of fabricating composite materials. Two workable systems, styrene-acrylonitrile copolymer (SAN)-acetanilide and SAN-anthracene, were found and their phase diagrams determined. In both systems kinetic studies revealed that the maximum crystallization rate takes place at large degrees of supercooling and that below these temperatures the mechanism is diffusion-controlled. The temperature-dependent crystal morphologies were characterized with electron microscopy, which showed three distinctly different morphologies for both systems. From dynamic mechanical measurements, it appears that the elastic moduli of organic crystals are about the same as those of organic polymers in the glassy state, and that relatively little reinforcement took place under the particular crystallization conditions employed.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1968.070120514
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  • 17
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    Electronic Resource
    Ceric ion-induced redox polymerization of acrylonitrile on cellulosePresented at the 6th Joint Technological Conference of ATIRA, BTRA, and SITRA, Bombay, January 1965, and at the Annual Convention of the Indian Chemical Society held at Anand, December 1966. (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 1321-1342 
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    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The ceric ion-cellulose redox system has been studied for grafting acrylonitrile on cotton fibers. Grafting yields are very high as compared to the persulfate-thiosulfate redox system reported earlier. Traces of copper sulfate in the reaction mixture do not increase grafting yields, unlike the persulfate-thiosulfate system. The high polymerization rate on cotton fibers is shown to be due to the reducing action of cellulose and not to the large surface area of cotton fibers. The Ce+4 consumption during grafting is higher than during oxidation of cellulose, indicating formation of homopolymer during the grafting reaction. Studies on the consumption of Ce+4 by model compounds such as D-glucose and α-methyl-D-glucoside show that the hemiacetal group in D-glucose is responsible for a faster rate of Ce+4 consumption. Formation of a Ce+4-alcohol complex also contributes to the initial fast rate of Ce+4 consumption. Studies on the oxidation of cellulose by Ce+4 indicate that the initial oxidative attack occurs on carbon atom 2, with the formation of a 〉C=O group. On further oxidation, cleavage of the C2-C3 bond occurs as shown by the presence of glycol aldehyde determined chromatographically. Cellulose-polyacrylonitrile grafts have been isolated by an acetolysis treatment followed by extraction with dimethylformamide. Number-average molecular weights of the isolated fractions are approximately 50,000-55,000. A theoretical method to calculate the number-average molecular weights, based on the PAN and the COOH contents of the grafted cellulose, is described.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1968.070120605
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  • 18
    Electronic Resource
    Electronic Resource
    Some viscoelastic properties of ABS polymer (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 1343-1353 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The discrete relaxation spectrum of an ABS (acrylonitrile-butadiene-styrene) polymer at 190°C. was calculated by using results from tensile relaxation moduli and the principle of reduced variables. The shift factor was found to conform well to the WLF equation, and the free volume fraction at Tg was calculated to be 0.026 in good agreement with the universal value. The values of the thermal expansion coefficient of free volume were calculated to be 9.8 X 10-4 deg.-1 and 7.0 × 10-4 deg.-1, respectively, from the WLF coefficients and from dilatometric results. The width of the entanglement plateau of the relaxation spectrum was observed to be a factor of approximately 2 larger than that calculated from molecular weights between entanglement couplings determined either from rubber elasticity theory or from an assumed molecular model which discounts the presence of the butadiene in the ABS system. By using Pao's theory, flow curves at 190°C. were calculated both from the discrete relaxation spectrum and from the dynamic modulus. These curves were essentially identical. However, the stress values of these curves were found to be about a decade higher than those experimentally determined from capillary flow measurements. Nevertheless, the shapes of the curves are in good agreement, and an explanation is suggested for existing discrepancies. Flow instability, processing variables, and residual strains are discussed in light of the flow curves and the calculated recoverable shear strains.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1968.070120606
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  • 19
    Electronic Resource
    Electronic Resource
    Influence of cohesive forces on the glass transition temperatures of polymers (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 1397-1409 
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    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: The relationship between cohesive energy (c.e.) or cohesive energy density (c.e.d.) and the glass transition tenperature (Tg) of polymers has been re-examined on the basis of literature data. For polymers with Tg above 25°C., there is no correlation between published or calculated values of c.e. or c.e.d. and Tg. However, for the rest of the polymers there is a linear relationship between c.e.d. and Tg, and a broad relationship between c.e. and Tg. These results imply that c.e.d. is the regulating, though not the only, factor in determining Tg's up to values of approximately 25°C.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1968.070120612
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  • 20
    Electronic Resource
    Electronic Resource
    ESR study of reactions of cellulose with ·OH generated by Fe+2/H2O2 (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 1411-1421 
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    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: It was demonstrated by ESR spectroscopy that the Fe+2/H2O2 system gave a reactive species which generated an ESR triplet spectrum or sorbitol similar to that generated by hydroxyl radicals from the Ti+3/H3O2 system. An ESR spectrum was obtained for the hydroxyl radicals generated by the latter system. However, the lifetime of hydroxyl radicals, generated by the Fe+2/H2O2 system, was apparently very short, and an ESR spectrum for the hydroxyl radicals, generated by this system, was not observed. The Fe+2/H2O2 system also generated triplet spectra with cotton cellulose I, cotton cellulose II, and microcrystalline cellulose, suggesting that a hydrogen atom had been abstracted from the hydroxyl group on carbon C6, or possibly the hydrogen atom on carbon C5. The ESR spectrum generated on microcrystalline cellulose was less intense than those generated on cellulose I and II. On initiation of graft polymerization of the activated cellulose with acrylonitrile, the triplet spectrum disappeared and was replaced by two strong singlet spectra. One of the singlet spectra was likely generated on carbon C1 or C4 on depolymerization of the cellulose molecule, and the other was probably generated on the end of the growing polyacrylonitrile molecular chain. The absence of a triplet spectrum gave direct evidence for the order in which the acrylonitrile monomer was being grafted onto the cellulose molecule. The mechanisms proposed by Haber and Weiss for the reactions generated in the Fe+2/H2O2 system were generally supported.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1968.070120613
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  • 21
    Electronic Resource
    Electronic Resource
    Polymerization of propylene oxide with Ziegler-Natta catalysts (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 1477-1479 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1968.070120619
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  • 22
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    Electronic Resource
    Mechanochemical degradation of an EPDM polymerThis paper was presented at the joint meeting of the Rubber Division, A. C. S., and C.I.C. (Canada) in Montreal, May 2-5, 1967. (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 1459-1469 
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    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A mill-mastication study of an EPDM polymer (DuPont, Nordel 1070) was conducted in the mill-roll temperature range of 68-480°F. The extent of degradation was determined by dilute-solution viscosity measurements. The role of oxygen in the polymer mastication was followed by infrared spectroscopy. The breakdown of the EPDM polymer on the mill is minimum in the temperature range of 185-315°F. Up to 315°F. the increase in temperature leads to a decreased amount of degradation. During cold mastication mechanical breakdown occurs. The use of a free-radical acceptor shows that this type of breakdown is caused by the mechanical rupture of C—C bonds in the polymer chain. At and above 350°F. thermooxidative degradation becomes dominant, the polymer degrading drastically, and the higher the temperature, the greater the extent of degradation for the same period of mastication. Infrared spectroscopy shows that hot mastication results in decreased double-bond concentration and increased amounts of carbonyl and, possibly, anhydride and lactone groups. Of the carbonyl groups formed 30% are due to the oxidation of double bonds in terpolymer and 70% to the oxidation of the main chain. A mechanism is proposed to account for these observations.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1968.070120617
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  • 23
    Electronic Resource
    Electronic Resource
    The energetics of ion transport in the presence of polymeric compounds which alter the rheological properties of water (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 1484-1485 
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    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1968.070120621
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  • 24
    Electronic Resource
    Electronic Resource
    Note on the iterative calculation of relaxation spectra (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 1649-1652 
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    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The use of exact numerical methods for calculating spectra from dynamic moduli is shown to lead to acceptable results when a modified numerical method is employed. The modification avoids the wild oscillations encountered with existing methods when difficult experimental data containing sudden spectral cutoffs must be analyzed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1968.070120713
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  • 25
    Electronic Resource
    Electronic Resource
    The modulus and yield stress of glassy poly(methyl methacrylate) at strain rates up to 103 inch/inch/second (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 1653-1659 
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    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Specimens of poly(methyl methacrylate) (PMMA) were compressed at nominally constant strain rates ranging from 10-5 to 103 in./in./sec. at 0, 22, 50, and 115°C. A plot of stress at a small fixed strain (2%) and constant temperature versus logarithm of strain rate is sigmoidal in shape and, furthermore, time-temperature superposition could be used to construct a master curve of stress versus temperature-compensated strain rate. It is suggested that the sigmoidal curve is a manifestation of the β transition in PMMA, and this is supported by the measured value of activation energy and the strain rate value at the point of inflection on the curve. By contrast, yield stress varies linearly with log \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {\rm \varepsilon }\limits^{\rm.} $\end{document}. Time-temperature superposition could not be applied. Rationalizing on the basis of the high stress form of the Eyring equation, yielding is by a yet unspecified molecular mechanism in which activation volume has the order of magnitude of a monomer unit but increases with increasing temperature.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1968.070120714
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  • 26
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    Electronic Resource
    Properties of solutions of poly-N-vinylcaprolactam (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 1835-1842 
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    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The properties of poly-N-vinylcaprolactam organic and aqueous solutions were studied. Toluene solutions present an increasing [η] from 10 to 40°C. Aqueous solutions present a very accentuated diminishing of [η] from 10 to 30°C. Above 30°C. The polymer precipitates from its aqueous solutions. The precipitation temperature does not depend on the concentration but on the molecular weight of the polymer. Some acid and basic agents have a marked influence on [η] and the precipitation temperature of the aqueous solutions.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1968.070120804
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  • 27
    Electronic Resource
    Electronic Resource
    Radical bulk polymerization of N-vinylcaprolactam (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 1843-1851 
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    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Bulk radical polymerization of N-vinylcaprolactam was studied at temperatures between 60 and 120°C. with different initiators. Satisfactory results were obtained with azobisisobutyronitrile, tert-butyl perbenzoate, and tert-butyl peroxide as initiators. The polymerization reaction of N-vinylcaprolactam with these initiators is first order with respect to the monomer and 0.5 order with respect to the initiator. A linearity of the kinetic curves up to high conversions was observed. The cause of this behavior is a feeble gel effect, which also induces an increase of the molecular weight during polymerization.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1968.070120805
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  • 28
    Electronic Resource
    Electronic Resource
    Determination of degree of nitration of nitrocellulose by refractometry (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 1865-1871 
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    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Nitrocellulose (NC) films, when dried on a rigid substrate, tend to be biaxial and thus exhibit two refractive indices. The absolute difference between these indices has been found to provide an accurate measure of the degree of nitration of NC. A film of NC is cast from a 1% solution in butyl acetate to provide a film about 0.5 mil thick. The dry film, when placed in an Abbé-3L refractometer, gives two white lines which go to extinction alternately upon rotation of a cap analyzer through the east-west (EW) and north-south (NS) directions. Refractive index measurements are made using the line visible in each direction of the analyzer. The absolute difference between the two indices is related to the degree of nitration through standard curves for various grades of NC. The standard deviation for the proposed method was found to be ±0.01% N.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/app.1968.070120808
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  • 29
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    Electronic Resource
    Some properties of low molecular weight polybutadiene and polytetrahydrofuran (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 1889-1899 
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    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: The proposition, that low molecular weight polymer fractions in good solvents behave as if they were under ⊖ conditions, has been examined experimentally. Series of monodisperse hydroxy-terminated polytetrahydrofuran (PTHF), 82% 1,4-polybutadiene (PBD), and 30% 1,4-PBD were prepared, and values of M̄n obtained by vapor-pressure osmometry and endgroup analysis. The Mark-Houwink viscosity parameters K and ν were determined in a number of solvents. The general conclusion is that the proposition is invalid for these systems notwithstanding the fact that ν = 0.50 for one of them [82% 1,4-PBD in methyl ethyl ketone (MEK) at 25°C]. For this particular case, the following evidence suggests that these are actually ⊖ conditions so that the apparent fulfilment of the proposition is fortuitous. (1) Cloud-point precipitation yields ⊖ = 26 ± 3°C in MEK. (2) The value of K is close to that of K⊖ found elsewhere for PBD in a different solvent at a similar temperature. (3) Application of the Kurata-Stockmayer iterative procedure for estimating K⊖ from data in good and bad solvents yields a reasonably small discrepancy (10%) between the K⊖ values from data in toluene and MEK at 25°C for this polymer and only a 3% difference in the unperturbed dimensions (〈r02〉/M)1/2 derived from them. Measured melting points Tm of PTHF (M̄n = 1000-13000), plotted as a function of chain length Z, viz., 1/Tm = 1/Tm0 + 2R/ZΔHf, yield 43 ± 3°C and 1.6 kcal/submole, respectively, for the limiting melting point Tm0 and the heat of fusion ΔHf. The former is in good agreement with the value obtained dilatometrically for high molecular weight polymer, while the latter indicates a degree of crystallinity of ca. 54%.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/app.1968.070120810
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  • 30
    Electronic Resource
    Electronic Resource
    Effects of thermal history on polypropylene fractions (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 1921-1938 
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    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The effects of thermal history on the melting behavior of several polypropylene fractions have been studied. The specific fractions investigated include one that has crystallized in the triclinic modification, one that has crystallized in the monoclinic modification, and a third that contained a combination of the two types of crystals. Thermal histories given to these specimens included a series of stepwise annealings at steadily decreasing temperatures, a series of annealings for various times at a given elevated temperature, and a series of stepwise annealings at a set of steadily increasing temperatures. The melting behavior was investigated by means of a differential scanning calorimeter and various DSC peaks are presented. The nature of multiple peaks produced by the different treatments is discussed, and the results are compared with similar data obtained on whole polymer.
    Additional Material: 13 Ill.
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    URL: http://dx.doi.org/10.1002/app.1968.070120812
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    Analysis of bisphenol A sulfonate-carboxylate polymer (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 2039-2045 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The method of analysis for a polycondensation polymer containing the carboxylate and sulfonate functional groups has been devised. A combination of infrared spectroscopy and combustion analysis provides a simple and accurate determination of the monomeric units and their molar distribution in the polymer.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/app.1968.070120906
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  • 32
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    Chlorination of polystyrene (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 2059-2066 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Chlorination of a low molecular weight polystyrene in the α position was studied by following changes in the infrared spectrum, glass transition temperature, and molecular weights of the polymer. The logarithm of the absorbance ratio at 2920 and 1500 cm-1 as a function of mole per cent chlorination was linear. The glass transition temperatures, determined by use of a differential scanning calorimeter (DSC), were found to obey an equation developed by Dyvik for copolymers. The molecular weight of the chlorinated polystyrene decreased as a function of chlorination.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/app.1968.070120908
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    Detection of polymer transition temperatures by infrared absorption spectrometryPaper presented at the 154th Meeting of the American Chemical Society, Chicago, September 1967. (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 2117-2128 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Infrared bands in the 900-1100 cm-1 region are sensitive to thermal energy. These bands can result from intermolecular coupling, producing the crystal lattice, or from intramolecular coupling of the various atomic groups in a regular helix or coiled chain. In either case an increase in temperature will disrupt the coupling mode, resulting in a form of structural relaxation and a reduction in the integrated absorbance. It is proposed that the temperature at which the peak areas begin to decrease be assigned as the Tg. This is measured by continuously scanning a selected peak in the infrared spectrum of a polymer film while it is heated at a rate of about 1°C/min. Using this technique polyamides (nos. 6,66, and 610) exhibited transitions in the 30-50°C range, and by studying the increase in the free NH region (3440 cm-1) of nylon 66 two other transitions were detected at 80 and 137°C; the latter represents a change in the nylon 66 crystal state. An amorphous film of poly(ethylene terephthalate) displayed a transition at 58-68°C (Tg) and at 85°C, which is the crystallization temperature. Films of poly(vinyl acetate) and polystyrene exhibited transitions at 25-37°C and at 70°C, respectively.
    Additional Material: 12 Ill.
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    URL: http://dx.doi.org/10.1002/app.1968.070120915
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    Radiation chemical studies of protein reactions: Radiation dose and viscosity change (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 2747-2747 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1968.070121222
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    A dynamic mechanical study of the effect of chemical variations on the internal mobility of linear epoxy resins (polyhydroxyethers) (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 12 (1968), S. 2747-2747 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1968.070121223
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    The physical properties of polyacrylonitrile and its copolymers (1968)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science: Macromolecular Reviews 3 (1968), S. 113-254 
    Details
    ISSN: 0076-2083
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 49 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.230030103
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    Hydrodynamic properties of DNAThe preparation of this review was supported in part by USPHS Research Grant GM 12555. (1968)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science: Macromolecular Reviews 3 (1968), S. 255-316 
    Details
    ISSN: 0076-2083
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.230030104
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  • 38
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    Polymer degradation by differential thermal analysis techniques (1968)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science: Macromolecular Reviews 3 (1968), S. 49-112 
    Details
    ISSN: 0076-2083
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 34 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.230030102
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  • 39
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    The use of living polymers in the preparation of polymer structures of controlled architecture (1968)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science: Macromolecular Reviews 3 (1968), S. 317-401 
    Details
    ISSN: 0076-2083
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 23 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.230030105
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  • 40
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    The development of the female Drosophila reproductive system (1968)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 124 (1968), S. 143-165 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Light and electron microscopical studies allow a descriptive account to be given of the preadult development of the ovary of Drosophila melanogaster. The lineage of the cell groups which contribute to the tissues of the adult ovary has been determined. The earliest morphologically detectable event in the differeentiation of each ovariole is the formation during the larval period of its terminal filament. Oogonia play no role in the induction of terminal filaments. The developmental events which transform a spherical mass of ovarian cells into a collection of multicellular cylinders is described. The importance in morphogenesis of acellular membranes secreted at the interface separting cells of different prospective significances is stressed. Such membranes may serve to regulate the future migration of cell populations or as sites of attachment for monolayers of cells which later fuse to form multinucleated muscle sheaths. The transformation of oogonia to cystoblasts coincides with and presumably depends upon the same hormonal stimulus which causes metamorphosis. The first oocytes to undergo crossing over do so between 24 and 36 hours after puparium formation.
    Additional Material: 19 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1051240203
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    Morphology of the presoma of Corynosoma hamanni (Acanthocephala: Polymorphidae) (1968)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 124 (1968), S. 217-225 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A morphological study of the presoma of adult Corynosoma hamanni (Linstow, 1892) was undertaken in an effort to clarify some problems encountered during analysis of a large collection of juveniles of this species assembled from fishes of McMurdo Sound. This study is based on approximately 600 adult specimens recovered from four Weddel seals, Leptonychotes weddelli, collected at McMurdo Sound.Morphologically the proboscis armature is more varied than previously reported and consists of 18 to 23 longitudinal rows each with 11 to 15 hooks of two distinct types. At the apex of the proboscis is an undivided, bi-nucleated apical organ unlike that described for species of Neoechinorhynchus. In the basal third of the proboscis is a thin-walled vesicle which extends into the anterior quarter of the proboscis receptacle. The more posterior of two external folds on the presoma is a cuticular invagination permitting recognition of the neck-trunk border of C. hamanni. Lemnisci originate between the two folds and extend into the trunk cavity between the body wall and extensive neck retractor muscles. Contrary to Linstow's original description, each lemniscus is a single structure.Several limitations in material prevent speculation at this time about the limits of intraspecific variation in C. hamanni.
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    URL: http://dx.doi.org/10.1002/jmor.1051240207
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    Intraneural vascular response to defective development of the chick mesencephalonSupported by grant 5 RO1-HD-01679-02 from the USPHS National Institutes of Health. (1968)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 124 (1968), S. 295-311 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The development of intraneural vessels was studied in response to an induced hypermorphosis of neural tissue inthe midbrains of 38 chick embryos ranging in age from three days through 14 days of incubation. The pattern of vascularization was compared with that of normal chick embryos at comparable stages of development. In the experimental embryos, the increase in mitotic figures along the ventricular borders of the mesencephalon is accompanied by the establishment of an endoneural plexus approximately one day earlier than is the case during normal vascularization of the midbrain. This plexus also penetrates more deeply and extensively into the ependymal layer. Surface vessels and intraneural vascular elements are dilated, and the cerebrospinal fluid contains varying amounts of blood released from large intraneural vessels which protrude into the ventricle. The most prominent cerebrovascular effects seem to occur between the fourth and eighth days of incubation. Thereafter, the cerebrovascular pattern becomes more normal except for relatively few isolated hemorrhagic areas.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1051240304
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    Structure of the eye of Haideotriton wallacei, a North American troglobitic salamander (1968)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 124 (1968), S. 345-351 
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    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The eye of Haideotriton wallacei is more reduced histologically than those of othe troglobitic salamanders. The tiny eye is imbedded in a mass of adipose tissue. No extrinsic eye muscles are present. A rudimentary lens is present in about half of the eyes examined. In two instances the lens is surrounded by a small chamber; most eyes lack a chamber. The retina and iris are relatively undifferentiated. The relatively massive retina lacks rods and cones, an outer plexiform layer and subdivided nuclear layers. A tiny optic nerve runs to the brain.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1051240307
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    Fine structure of the aesthetasc hairs of Coenobita compressus edwardsThis work was supported by University of California Faculty grant 308 and U.S. Public Health Service grant NB04372. (1968)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 124 (1968), S. 361-385 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The aesthetascs, short thin-walled pegs on the antennule flagella of Coenobita clypeatus, a terrestrial hermit crab, are similar to those of other decapod crustacea in containing the dendrites of many bipolar neurons whose cell bodies are grouped in spindle-shaped masses beneath the bases of each hair. The dendrites contain rootlets, basal bodies, and cilia, which divide dichotomously before entering the aesthetasc, so that within the hair, each cilium becomes represented by a group of slender branches.The aesthetascs themselves are short, blunt, and partially recumbent so that each has an exposed and an unexposed side. The cuticle on the exposed side is thinner and more tenuous than that on the protected side, and the dendrite branches are concentrated just underneath. The protected side, on the other hand, is lined with nondendritic supporting cells, and the cuticle is thicker, more lamellar, and probably less permeable.All dendritic elements proximal to the dendrite branches are enclosed within the main body of the antennular flagellum, and the initial segments of the cilia lie within a vacuole. In these respects, the aesthetascs of Coenobita resemble the thin-walled pegs on insect antennae more than they do those of the marine decapods thus far examined. This convergence in the terrestrial forms may be in response to the need to conserve water.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1051240309
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    A light and electron microscopic investigation of the digestive system of the Ophiuroid ophiuroiderma panamensis (Brittle Star)This work was supported in part by U.S.P.H.S. grant NB 03604. (1968)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 124 (1968), S. 451-481 
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    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The Brittle Star digestive system is composed of buccal, pharyngeal, esophageal and stomach cavities. The buccal and pharyngeal cavities are lined by columnar cells covered by a cuticle, and are apparently concerned with mucous production. Coelomocytes and tall columnar cells are described in the esophagus and stomach epithelia. The columnar cells are adapted for nutrient absorption, enzyme synthesis, and lipid storage. Nerves are found beneath the epithelia within a connective tissue layer. Smooth muscle and coelomic layers lie external to the connective tissue layer. The coelomic layer lines a perivisceral space and has diverse modifications of its perivisceral surface; a pedicle-cuticle modification perhaps having general significance in echinoderms.
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    URL: http://dx.doi.org/10.1002/jmor.1051240405
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    The fine structure of the Limulus optic nerve (1968)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 125 (1968), S. 61-70 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Two complete composite photographs of the optic nerve of Limulus, made by electron microscopy, reveal the presence of neurosecretory granules in the large axons of the rudimentary eye neurons. The number of intermediate sized, (3-7 μ), of eccentric cells corresponds with the number of ommatidia as expected, but only their sheath of Schwann cells show an intimate interfolding. Based on the number of fine axons within the nerve each ommatidium has an average of 12-13 retinular cells. The diameter of their fibers is between 0.2 and 3 μ although the majority are between 1 and 1.5 μ. They are aggregated into bundles of six to seven fibers by the sheath cells although some bundles contain only two, others as many as 181 fibers. There is no indication in these studies that retinular cell axons within a bundle are associated with the same, adjacent, or other pattern of ommatidia. The photographs suggest that physiological activity in retinular cell axons might be detected most easily in the smallest bundles because they contain the fewest, but the larger retinular cell axons.
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    Anatomical changes in the neuromuscular complex of the proleg of Galleria mellonella (L.) (Lepidoptera: Pyralidiadae) during metamorphosisBased on part of a thesis submitted in partial fulfillment of the requirements for the Doctor of Philosophy degree in the Department of Entomology and Parasitology, University of California, Berkeley. (1968)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 125 (1968), S. 105-127 
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    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The lateral and ventral external surfaces of the third and fourth abdominal segments were described and muscle attachments were correlated with surface indentations of the larva. The proleg of this species has a symmetrical planta with a complete circle of crochets. Furthermore, it differs externally from the grasping type of proleg in having a largely membranous coxal region confluent with the body wall, and a relatively large subcoxal lobe.The body wall musculature and innervation of the third and fourth abdominal segments are similar in many respects to those described for other lepidopteran larvae to which they are here compared, but differ from most because of the simpler structure of the prolegs which lack highly developed adductor muscles. Like most muscles innervated by the ventral nerve, the principal plantar retractors of these two segments cease to function in the first day of the pupal stage and have completely degenerated by the forty-fifth hour of pupal life. The ventral nerve retains its four primary branches in the adult, in which many smaller rami can be traced to the cuticle and to the neoblastic body wall muscles.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/jmor.1051250106
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    Symmetrical gaits of dogs in relation to body build (1968)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 124 (1968), S. 353-359 
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    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Symmetrical gaits of 37 breeds of dogs were analyzed. Usual walking and trotting gaits resemble those of other carnivores of similar size and conformation. Only certain long-legged dogs pace - usually at the fast walk or slow run. At the moderate walk, long-legged dogs tend to use lateral-couplets gaits, whereas short-legged breeds tend to use single-foot gaits. Many dogs must turn the axis of the body slightly from the line of travel at the trot to prevent interference between fore and hind feet. The relative duration with the ground made by fore and hind feet is discussed, usual support-sequences of the varicus gaits are presented, and the amount of variation is shown.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1051240308
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    H3-proline incorporation into cartilage: Electron microscope autoradiographic observations (1968)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 124 (1968), S. 387-421 
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    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Electron microscope autoradiography was used to study cartilage from regenerating limbs of adult newts, Triturus, after intraperitoneal injections of proline-3H. The labeling in the endoplasmic reticulum, small vesicles, Golgi vacuoles, ground cytoplasm and extracellular matrix was compared during the secretion of radioactive products. The data appear to indicate that a large part of the radioactive secretion probably leaves the cell after having been in only one cellular compartment. Although this compartment may be the endoplasmic reticulum, a considerable amount of radioactivity fluxes through the ground cytoplasm and the possibility cannot be excluded that some secretory components leave the cell directly from the ground cytoplasm. The data appear incompatible with the hypothesis that all the radioactivity seen in the extracellular matrix arrived there via a single pathway involving first the endoplasmic reticulum and then the Golgi vacuoles. It is not, however, incompatible with a hypothesis that a fraction of the radioactive product uses this pathway.
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    URL: http://dx.doi.org/10.1002/jmor.1051240402
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    Masthead (1968)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 125 (1968) 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051250101
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    Masthead (1968)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 125 (1968) 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051250401
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    Lymphatic capillaries in tail fin of amphibian larva: An electron microscopic studyThis work was supported by USPHS grant AI-07348 and the Shriners Burns Institute, Boston Unit. (1968)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 125 (1968), S. 419-445 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ultrastructure of lymphatic capillaries in the tail fin of Rana catesbiana larvae was investigated. With the use of a colloidal marker particle (Biological Carbon) the extent that these delicate vessels ramify throughout the fin region was demonstrated. This opaque substance also serves as a marker particle for identification of lymphatics with some degree of certainty at both light and electron microscopic levels. The cytoplasm of the lymphatic endothelial cell is abruptly attenuated beyond the perinuclear region, reaching widths as thin as 300 Å. Lymphatic Anchoring filaments are present, but to a lesser degree than noted for other species studied. Other features of interest include an extensive Golgi complex and electron dense bodies that are surrounded by a smooth surfaced unit membrane. These bodies are somewhat heterogeneous in size (500 Å up to 0.5 μ in diameter) and density. Numerous exit channels are provided by the extensive supply of lymphatics throughout the tail fin region of amphibian larva thus allowing them to serve an important function during metamorphosis. It is suggested that these vessels also act as passageways through which lysed cellular and connective tissue components may be rapidly removed during the process of tail fin resorption.
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    URL: http://dx.doi.org/10.1002/jmor.1051250404
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    The body wall of cheilostome bryozoa. I. The ectocyst of Watersipora nigra (Canu and Bassler)This work is to be submitted to the graduate faculty of the University of Southern California in partial fulfillment of the requirements for the degree of Doctor of Philosophy. The research, conducted at the University of Southern California, was supported in part by an NIH Biomedical Science Support grant 1-S05-FR-07012-01. Contribution 307 of the Allan Hancock Foundation. (1968)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 125 (1968), S. 497-507 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The cuticle of Watersipora nigra is at first translucent, but it later becomes black and differentiates into two layers. It is composed, at least in part, of a protein-polysaccharide complex. Calcified parts are three-layered: (1) an outer, cuticular layer, (2) a calcium carbonate skeleton deposited on a matrix of acid mucopolysaccharide, and (3) a “skeletal membrane.” The relationships of these layers indicate that the skeleton is intracuticular. A layer of cuticular material, the “intercalary cuticle” is present in lateral walls, but not transverse walls; it may become calcified in some species. The cuticles of calcified and uncalcified parts of cheilostomes are not necessarily homologous.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1051250407
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    The distribution of peritubular matrix in human coronal dentin (1968)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 126 (1968), S. 435-445 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Thin semi-serial ground sections of coronal dentin were examined radiographically. The bulk of the coronal dentin was characterized by the majority of the tubules having a distinct peritubular zone. With the exception of the tubules running from the tip of the cusp to the pulp cornu, the bulk of peritubular matrix forming the walls of the tubules was disposed eccentrically. The matrix was thicker on the cervical sides of the tubule than it was on the incisal sides. In a relatively narrow layer of the coronal dentin between the bulk of the dentin and the predentindentin border area the thickness of the peritubular matrix varied considerably. It was extremely narrow or absent in some tubules and reached its greatest thickness in others. The tubules in the predentin border area showed little or no evidence of peritubular matrix. The area of dentin beneath the central developmental groove differed somewhat from the bulk of the dentin. Many of the tubules at all levels of this area showed little radiographic evidence of peritubular matrix. Obliterated tubules were seen in some of the sections taken immediately above the predentin-dentin border area in the region of the pulp cornu and were always seen at the junction of the mantle dentin and the circumpulpal dentin beneath the central developmental groove.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1051260405
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    Development of zonular patterns in the human adrenal glandThis investigation was supported, in part, by Public Health Service Research grant 5-SO1-FR-05409-05 from the National Institute of Health General Research Support Grant. (1968)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 126 (1968), S. 477-491 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Microscopic studies of human adrenal glands from 58 autopsy specimens, ranging in age from one month gestation to 69 years, revealed a pertinent developmental pattern in the establishment of definitive zonation. This pattern was established using the following criteria: (1) relationship of age to the developing zones; (2) times of formation of definitive zonation; and (3) the morphological determination of developmental patterns based on staining characteristics.Using these criteria, development was divided into five phases: (1) condensation of coelomic epithelium; (2) secondary proliferation of coelomic epithelium; (3) finding of PAS-positive material within the fetal cortex; (4) decline and disappearance of the fetal cortex; and (5) establishment and stabilization of the definitive zonular patterns.Significant features occurring in this development were: (1) the origin of both permanent and fetal cortex from proliferation of coelomic epithelium; (2) the appearance of PAS-positive granules surrounding a homogenous mass in the fetal cortex and the zona reticularis during maturation and organization; and (3) the gradual establishment of definitive zones by proliferation of the permanent cortex, maturation of the fetal cortex, and growth of the medulla; with the adult structure of the adrenal gland achieved by the eleventh to fifteenth year without any apparent major involution or hemorrhage.
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/jmor.1051260408
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    Masthead (1968)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 124 (1968) 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051240101
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    Mean weights of chick embryos correlated with the stages of Hamburger and Hamilton (1968)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 124 (1968), S. 79-82 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A total of 1125 normal chick embryos, representing 25 each of the 45 stages of Hamburger and Hamilton, were removed, fixed in Bouin's solution, stored in 70% ethanol and weighed with a semi-micro analytical balance. Entire blastoderms of stages 1-8 were weighed, whereas only embryos-proper were weighed in stages 9-45. As a consequence, results constituted two groups, each of which showed a geometric rate of growth marked only by minor deviations which were related to specific events of normal growth and development.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1051240105
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    Quantitative studies of superior cervical sympathetic ganglia in a variety of primates including man. I. The ratio of preganglionic fibers to ganglionic neurons (1968)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 124 (1968), S. 117-131 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Estimates of the number of ganglionic neurons of superior cervical sympathetic ganglia and the number of preganglionic axons in the trunks just caudal to these ganglia were obtained from a sample of primates that included: man, chimpanzee, baboon, stump-tailed macaque, rhesus monkey, and squirrel monkey. The number of ganglionic neurons ranged from 63,625 in a squirrel monkey ganglion to 1,041,652 neurons in a human ganglion. Estimates of the number of preganglionic fibers varied between 2,285 in a cervical sympathetic trunk of a squirrel monkey and 12,008 in a human specimen. The resulting ratios of preganglionic fibers to ganglionic neurons ranged from 1:28 in a squirrel monkey ganglion to 1:196 in a human ganglion.The data reported in this study reveal considerable variation in the ratio of pre- to post-ganglionic neurons, and as was noted in regard to the number of cells in the ganglion, the ratios of ganglionic to preganglionic neurons appear to increase as a function of body size. In contrast, the number of preganglionic fibers does not increase as strikingly with body size, but varies greatly in the same species. The resulting ratio between the two orders of neurons is, therefore, less predictable than the number of ganglionic neurons in any given ganglion.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1051240108
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    Adaptive problems and possibilities in the temporal fenestration of tetrapod skulls (1968)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 125 (1968), S. 145-157 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Adaptive explanations for the temporal fenestration in reptiles are briefly reviewed. With few possible exceptions, fenestrate appeared first in the reptiles, and have seemingly evolved independently in several different phyletic lines.The several explanations for fenestration offered by previous authors include speculations that open spaces in the skull permitted bulging of the jaw-closing muscles, and that fenestrae formed in areas of reduced stress where the presence of bone would be functionally useless. The first of these does not readily apply to initial evolutionary stages; the second is more satisfactory.Certain features of muscular attachments to bones are dealt with, and their implications applied to the fenestration problem to add another possible explanation (which need not contradict previously published suggestions).Considerations of cranial strength in tetrapod skulls led to speculations on the lack of fenestration in temnospondyls, anthracosaurs, microsaurs and cotylosaurs.Emargination of the skull roof in turtles is also discussed.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/jmor.1051250203
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    Fine structure of the down feather during its early developmentThis investigation was supported, in part, by research grants, 5R01 HD 01314 and 1S01 FR 05427, from the National Institutes of Health, at The University of Texas Medical Branch, Galveston, Texas. Portions of this research were done at the M. D. Anderson Hospital, Department of Biochemistry, Houston, Texas, and supported by National Cancer Institon, Texas, and supported by National Cancer Institute Training Grant, CA-05161, and at the Southwest Foundation for Research and Education, San Antonio, Texas, supported by grant FR-05519-04, -05, U.S.P.H.S. (1968)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 125 (1968), S. 185-203 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The down feather of the chick embryo has been examined by electron microscopy during three distinct stages of its early development; the presumptive stage, represented by dorsal skin of an area from which the feather organ will arise; the thickening stage, during which areas of the basal epidermis form spurs projecting into the mesenchyme, and the latter condenses under a thickened area of the epidermis; the elevation stage, at which time the basal epidermis flattens, the entire epidermis increases in thickness, and the underlying mesenchyme becomes more compact.As development proceeds the rough endoplasmic reticulum of the epidermal cells dilates, but during the elevation stage begins to flatten, and Golgi is observed with increasing frequency. The mitochondria do not appear to differ except for those in the periderm during the presumptive stage, in which case they reveal a vacant matrix and irregular cristae.Evidence is presented for actual contact between basal epidermal spurs and filopodia of cells within the mesenchyme, some of which contain numerous vesicles. The basal epidermal spurs are also seen in intimate association with collagen and anchor filaments and a network of reticulin.Evidence is also presented for the presence of neuronal elements within the mesenchyme during the thickening stage. Cross sections of cell processes within the condensations of the mesenchyme resemble unmyelinated nerve fibers, and cross sections of filopodia similar to arborizing axons abound at and within the basal lamina of both the thickening and elevation stages. Further support for the presence of nerve fibers within the mesenchyme comes from positive staining results with Bodian's and Ungewitter's methods.This comparative study of three stages of early development of the feather organ serves as a basis for more detailed investigations of each stage.
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    URL: http://dx.doi.org/10.1002/jmor.1051250205
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    Masthead (1968)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 125 (1968) 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051250301
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  • 62
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    Optical studies of the stress-induced crystallization of rubber (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1-30 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The low-angle light scattering by films of stretched natural and synthetic rubbers was investigated. Intense Vv scattering is found under conditions when crystallization occurs which is characteristic of the scattering from aggregates of dimensions comparable with the wavelength of visible light. These were identified with the γ fibrils described by Andrews. The dependence of scattering was studied as a function of light polarization direction, orientation direction, elongation, temperature, degree of swelling, type of swelling liquid, and degree of crosslinking. It was concluded that the scattering unit consists of an assembly of crystals with their chain axes parallel to the stretching direction, but (in the case of natural rubber at high elongations) with the fibril axis at a slight angle to the stretching direction. The scattering is not affected much by swelling but is decreased upon increasing the temperature. Upon recooling the scattering returns, but does so over several hours, indicating that much of the scattering arises from secondary crystallization.
    Additional Material: 23 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060101
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    Molecular weights and molecular weight distribution of polymers by equilibrium ultracentrifugation. Part II. Molecular weight distribution (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 111-127 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A method has been developed for determining the molecular weight distribution of a polymer sample from the sedimentation-diffusion equilibrium data for a solution under pseudo-ideal conditions. From some theoretical examples it appears that the method works well and that the molecular weight distribution can be determined with a reasonable degree of resolution. From three polymer samples (polyethylene, polystyrene, and polycaprolactam) the molecular weight distribution was determined in this way. The average molecular weights, M̄n, M̄w, M̄z, and Mz+1, calculated from these distribution functions agree well with those calculated directly from the equilibrium data.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060105
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    Flow birefringence and polydispersityPresented in part at the International Symposium on Macromolecular Chemistry, Prague, 1965. (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 141-154 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Flow birefringence data for dilute solutions of various linear and branched polymers of different degrees of polydispersity are discussed. The polymers considered are polystyrene, polypropylene, and polyethylene. By making use of a well-known stress-optical relation, reduced elastic normal stresses, which can also be interpreted as coil expansions, are plotted against reduced shear stresses. As elastic normal stresses are rather sensitive to the shape of the molecular weight distribution at high molecular weight, a characteristic, p, related to the skewness of the distribution, is obtained. Experimental values of p are compared with theoretical ones based on special types of distribution functions. Attention is paid to the method of extrapolating experimental results to zero shear stress and concentration.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060107
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    Determination of orientation of the crystalline and amorphous phases in polyethylene by X-ray diffraction (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 281-288 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: For polyethylene fibers, orientation parameters of the form 〈cos2 φ〉 were calculated from traces obtained with an x-ray diffractometer equipped with an orientation integrator. The angle φ is that which a crystal or molecular axis makes with the fiber axis. Traces over a continuous range of diffraction angle were obtained for (2/π)Iav, and also the weighted averages (2/π)Iav 〈cos2φ〉 and (2/π)Iav 〈sin2φ〉, where Iav is the intensity averaged over all orientations. The orientation for the crystal a, b, and c axes were determined from area measurements of the {110} and {200} lines, and the orientation parameter for the molecular axis in the amorphous phase was determined from area measurements of the amorphous halos. An undrawn fiber showed a slight a and c axis orientation along the fiber axis, and a slight transverse orientation of the b axis and the molecular axis. For a highly drawn fiber the orientation parameter for the c axis was 0.98 and for the molecular axis 0.65. The degree of crystallinity, measured from the (2/π)Iav versus 2θ traces, were 66.1% and 73.3% for the undrawn and drawn fiber, respectively.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060118
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    Stress-strain behavior of elastic materials. O. H. Varga. Interscience, New York, 1966. 190 pp. $11.00 (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 301-301 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060121
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    Polymer fractionation. II. The analytical problem (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 383-406 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Complete fractionations into 5, 10, and 20 fractions were calculated by a numerical method based on the Flory-Huggins theory in order to evaluate various procedures for determining the molecular weight distribution from fractionation data. If the initial distributions are wide, the differential distribution cannot be accurately reconstructed, not even if each fraction is characterized by two average molecular weights (instead of one, as is customary). In addition to this inadequacy in the evaluation procedure there are the experimental errors which further detract from the accuracy of the result. The integral distribution can, in some cases, be approximated fairly well by means of the Schulz method, provided that the polymer is separated into many fractions with narrow distributions. However, the integral distribution thus obtained does not reflect details in the differential distribution. Polymer fractionation does not appear to be a suitable procedure for accurate determination of the differential distribution. From the assembled material, a thermodynamic method has been derived which seems to hold out better prospects. It should enable the differential distribution to be directly determined from a detailed analysis of the liquid-liquid phase relationships, provided the free energy of mixing function of the system is known.
    Additional Material: 15 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060205
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    On the possibility of chain folding in solutions of normal paraffins and polyethylene (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 451-456 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A simple statistical thermodynamic argument is presented in which the probability of intramolecular chain folding of normal paraffins and polyethylene in solution is examined. This possibility is based on the existence of low-energy intramolecular conformations which are stable enough to overcome the tendency of a chain molecule to assume a random arrangement in solution. Some rough estimates of the magnitudes of energetic interaction in straight-chain hydrocarbons are made to demonstrate the plausibility of this hypothesis. The experimental support for this model arises from NMR spectra of normal paraffins in aromatic hydrocarbon solvents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060302
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  • 69
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    Electronic and ionic conductivity in nylon 66Presented in part at the 152md American Chemical Society Meeting, New York City, September 1966. (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 463-477 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The conductivity of dry poly(hexamethylene adipamide) (nylon 66) was measured as a function of time and temperature. Three temperature ranges were observed in which the time dependence of conductivity differed: (a) below 80°C. the conductivity decreased continuously with time; (b) between 80°C. and 110°C. the conductivity remained constant over long periods; (c) above 120°C. a continuous decrease in conductivity was again observed. In other experiments the volume of gas evolved from the nylon film was measured under continuous potential and compared with the total current passed through the sample. It was observed that above 120°C. the gas evolved corresponded to about one-half the volume calculated if the conduction process involved only protons. Below 120°C. the gas evolved corresponded to an increasingly small fraction of the total current until below 90°C. no evolution of gas was observed. This suggests that at temperatures above 120°C. conduction involves the transport of both protons and electrons, whereas at lower temperatures it is electronic. Mechanisms of conduction are discussed.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060304
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    Identification of a stereoblock poly(methyl methacrylate) sample with a stereocomplex (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 509-516 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Acid hydrolysis of a stereoblock poly(methyl methacrylate) sample leads to a mixture of isotactic and syndiotactic poly(methacrylic acid) which can be separated by electrophoresis. The experiment confirms the stereochemical identity between the so-called “stereoblock” poly(methyl methacrylate) and the stereocomplex which syndiotactic and isotactic poly(methyl methacrylate) form in the ratio 2:1. A possible mechanism of replica polymerization is suggested to account for this effect.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060308
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  • 71
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    Conformation and normal frequency distribution of polymer chains (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 529-558 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: It is argued on the basis of a simple model for a polymer chain that characteristics of conformation can be determined from the analysis of the frequency distribution of backbone vibrations. In a chain with one degree of freedom per repeat unit, a fold tends to uncouple the motions on each side of the fold. This transfers highest and lowest modes towards the mean value. Conversely, a local unfolding of a random chain enhances the coupling and produces out-of-band modes. From the ordering of these modes, statistical aftereffects can be detected. The Green's function method allows a calculation of the single localized mode as a function of angular parameters. The dynamical matrix elements of the Kirkwood-Pitzer model are calculated for a folded polyethylene backbone chain. The eigenvalue distribution is determined with the Givens-Sturm procedure. It indicates a one-to-one correspondence between modes in the vicinity of 670 cm.-1 in the stretch-bend gap and chain folds, for low concentration of folds. We conclude that conformations should have two characteristic parameters distinctively reflected in the frequency distribution, namely the range of allowed dihedral angles and the ordering of configurations along the chain. The frequency distribution for a given conformation depends however on the force constant ratios when the degree of freedom is greater than one. Interpretation of the frequency spectrum is then made by adjustment of dynamical and geometrical parameters. These are seen to be dependent variables with respect to the spectrum.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060310
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  • 72
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    Load drop at the upper yield point of a polymer (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 607-620 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The stress-system curves have been measured for isotropic and oriented specimens of poly(ethylene terephthalate) in extension, shear, and compression. It was found that for all these types of deformations there was an intrinsic yield drop, i.e., a fall in true stress. It is concluded therefore that the stress for initiation is greater than the stress for propagation of yielding.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060314
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    Distribution of tensile data of vulcanized rubbers. I. Tensile data of SBR vulcanizates loaded with light calcium carbonate (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 639-651 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: When the first asymptotic probability function of smallest values was applied to analyze the distribution of tensile strength data for rubbers, good agreement between observed values and theory did not always result. In order to improve the agreement, use of another distribution function, the third asymptotic probability function, was proposed. Experiments verified that this function yielded good agreement with theory for the distribution of tensile strengths of rubbers, especially for SBR vulcanizates loaded with light calcium carbonate. The third asymptotic probability function contains three parameters: the characteristic value V, the lower limit ε, and the shape parameter k which is dimensionless. Analysis is made by use of a logarithmic extremal probability paper on which the probability function plots as a straight line if ε = 0. There appears to be a lower limit for the distribution of tensile strengths but not for the distribution of elongations. This suggests that the tensile properties follow the third asymptotic distribution function, with the breaking elongations following the simplified form of the Weibull distribution.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060316
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    Diffusion in atactic polystyrene above the glass transition point (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 675-685 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Diffusivities and solubilities in the system n-pentane-polystyrene were measured for low penetrant concentrations at several temperatures above the glass transition temperature. The relatively sharp changes in the activation energy of diffusion and the heat of solution near 150°C. are interpreted tentatively as indicating that a second-order transition exists in atactic polystyrene above the glass transition temperature. Evidence indicating the existence of this transition has been obtained by other techniques and the effects observed in this study should also be present in the diffusion of other penetrants in polystyrene. Correlation of these and other available data for diffusion in polystyrene as a function of the molecular size of the penetrant indicates that specific thermodynamic interactions between polymer and penetrant have little influence on the diffusion process.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060403
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    Temperature dependence of the bulk crystallization rate of polymers (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 695-706 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Data already existing in the literature for the overall crystallization kinetics of a variety of polymers have been analyzed according to different possible nucleation mechanisms. The conclusions reached are similar to those previously deduced from an examination of ata for spherulite growth rates. It is demonstrated that, if allowed a reasonable choice for the equilibrium melting temperature, no unbiased selection of a unique nucleation process can be made. Moreover, a set of universal parameters exists for each of the nucleation and growth processes considered which allows the data for all polymers to be represented by a single straight line. The only quantities that are unique to a given polymer are the equilibriun melting temperature and the activation energy for transport.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060405
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  • 76
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    Solution properties of poly(methyl acrylate) and (1:1) poly(styrene-co-methyl acrylate) (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 713-721 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Poly(methyl acrylate) (PMA) and 1:1 poly(styrene-co-methyl acrylate) (PSMA) were prepared by solution and bulk polymerization, respectively. The copolymer was analyzed with NMR to ascertain its composition and microstructure. The solution properties of unfractionated PMA and fractionated PSMA in ethyl acetate were investigated by light-scattering and viscosity techniques at 35°C. Narrow composition heterogeneity as revealed from the light-scattering measurements in different solvents justified the use of a single solvent for the copolymer characterization. The equations relating the limiting viscosity number to molecular weight, the molecular dimension to molecular weight, etc., were found for homopolymer and copolymers in ethyl acetate at 35°C. In the evaluation of the Flory constant K for the unperturbed state by methods based on Flory-Fox-Schaefgen, Kurata-Stockmayer, and Stockmayer-Fixman expressions, only the first method gave a value for PMA in ethyl acetate, consistent with that obtained in other solvents, whereas similar values of K were obtained by the three methods for PSMA in ethyl acetate. The studies indicate reduced thermodynamic interaction for PSMA-ethyl acetate compared to PMA-ethyl acetate, but increased steric effect in the copolymer compared with the homopolymer.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060407
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  • 77
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    Multiple-order light scattering from ringed spherulites (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 783-786 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Light scattering from polymer films containing ringed spherulites may show multiple-order intensity maxima directly related to the period of the banded structure. Calculations based on spherulite models where the angle of twist of lamellae ω varies linearly with radial distance predict only first-order peaks. If the variation of ω is nonlinear, even though the ring spacing remains constant, higher-order intensity maxima will result. Other sources of multiple-order scattering are considered. It is concluded that for polyethylene the presence of multiple-order scattering is due to non-uniform twisting of the lamellae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060412
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  • 78
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    Influence of crystallinity and orientation on sonic velocity and birefringence in poly(ethylene terephthalate) fibers (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 795-800 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060414
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  • 79
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    Crosslinked oligoethylene glycols: Correlation between their structure and some rheological properties (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 801-811 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Six oligoethylene glycols were crosslinked with triphenylmethane triisocyanate, and polymers with systematically changing network chain lengths were obtained and investigated. The 10-sec. torsion moduli versus temperature, glass transition temperatures, and cohesive energy densities of the polymers were determined and studied. The 10-sec. torsion modulus versus temperature plots show that all six polymers have a glassy transition and rubbery region of rheological behavior. The front factor calculated from the equation for the torsion modulus in the rubbery region when measured values of the modulus were used was compared with the front factor computed from equations that take into consideration molecular structures of the rubbery networks. With the exception of the case of crosslinked diethylene glycol the agreement in all the other cases between the values obtained for the front factor in both ways was good. In the investigated range of temperatures the polymers have below the glass transition temperature another transition point. The solubility parameters of the polymers, calculated from swelling experiments, were with the exception of the first member in the series almost identical.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060501
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  • 80
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    Infrared spectrum of poly(vinylidene fluoride) (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 861-869 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Two crystalline forms (α and β) of poly(vinylidene fluoride) were studied by infrared spectroscopy. The spectral differences permitted the study of the transformation and the ratio of the two forms. The ordinary \documentclass{article}\pagestyle{empty}\begin{document}$ \vec G,\vec F $\end{document} matrix method was used to calculate the fundamental mode with a Urey-Bradley type potential field, and a preferred set of the force constants was obtained.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060506
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  • 81
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    Nuclear magnetic resonance study of drawn poly(ethylene glycol) (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 653-656 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060317
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  • 82
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    Isochronal temperature-concentration diagram for a polymer-diluent system (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 687-694 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The results of an investigation of the viscoelastic and thermal properties of the gelatin-glycerol system are presented in the form of a complete temperature-composition diagram. This diagram shows the isochronal (10-sec.) mechanical behavior of the system along lines of constant modulus and thereby affords a convenient assessment of variation in viscoelastic behavior along any isotherm or isopleth of interest. Comparison of the results with previously obtained limited sets of data on a number of other polymer-dilent systems indicates the applicability and utility of such a presentation.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060404
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  • 83
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    Ductile behavior of single crystal mats of an ethylene-propylene copolymer (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 707-712 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: It is reported that mats formed by the sedimentation of single crystals of methyl- and ethyl-branched polyethylene exhibit strength and ductility comparable with that of melt-crystallized films. In fact, in the case of methyl-branched polymers, extensions of up to 50× were obtained on cold drawing. Observations on separate crystals suggest that this extension is due to the pulling out of individual lamellae. In view of the magnitude of the extension, this implies unfolding of the molecules. That considerable coherence can be obtained without original molecular ties between crystals is of significance as regards the molecular interpretation of the strength and ductility of crystalline polymers.
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060406
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  • 84
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    Unperturbed chain dimensions of isotactic polypropylene in theta solvents (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 735-744 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The unperturbed mean-square end-to-end distance 〈R02〉 and its temperature variation d In 〈R02〉/dT for isotactic polypropylene have been estimated from intrinsic viscosity data in three theta solvents, i.e., diphenyl, diphenyl ether, and dibenzyl ether, measured at their θ temperatures as determined by precipitation temperature measurements. The characteristic ratios, 〈R02〉/nl2, where n is the number of bonds of length l in the main chain, evaluated by assuming Φ = 2.87 × 1021, are 5.80 in diphenyl (at θ = 125.1°C.), 5.41 in diphenyl ether (at θ = 142.8°C.), and 4.56 in dibenzyl ether (at θ = 183.2°C.). These values lead to the temperature coefficient d In 〈R02〉/dT = -4.09 × 10-3 deg.-1 Results are compared with the data previously reported on polyethylene.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060409
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  • 85
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    Influence of microstructure on the hydrodynamic behavior of poly-α-methylstyrene (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 499-508 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The theta temperature of poly-α-methylstyrene in cyclohexane has been found to vary with the stereostructure of the polymer. The observed values range from 305.5°K. for highly syndiotactic material (0.95 syndiotactic diads) to 310.0°K. for anio ically polymerized samples (0.67 syndiotactic diads). Results indicate that the unperturbed dimensions of the polymer increase with increasing isotacticity of the chain, whereas the entropy parameter ψ1, measured in cyclohexane, decreased as the structure became more isotactic. Measurements of the second virial coefficient in toluene showed an increasing interaction with the solvent as the polymer became more syndiotactic.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060307
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    Upturn effect in the Non-Newtonian intrinsic viscosity of polymer solutions. II. Polyisobutylene in polybutene oil (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1011-1020 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: With an increasing gradient, the intrinsic viscosity of a high molecular weight polyisobutylene (M̄n = 7 × 106) in polybutene oil L.100 (ηs = 5 poise) first drops to a minimum and then rises again. The minimum occurs at β = M[η]0ηsG/NkT = 240, which is about ten times the value predicted by the dumbbell model. Such a shift to larger gradient is in good agreement with the more realistic necklace model of macromolecules in a good solvent. The increase of intrinsic viscosity after the minimum is nearly linear with the gradient and continues beyond the value at zero gradient. Experiments with capillaries of different length-to-diameter ratios yield identical flow curves so that one may exclude the possibility that the observed upturn is an artifact caused by end effects or time dependence of viscosity.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060519
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    Depolymerization studies on polyacetaldehyde (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1021-1033 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Depolymerization of amorphous polyacetaldehyde has been studied by measurements of weight loss versus time for thin films of the polymer in vacuum. Temperatures ranged from 40 to 80°C. The samples were prepared by freezing or melting the monomer in contact with treated glass surfaces. Light scattering, osmometry, and intrinsic viscosity measurements were used to characterize the polymers. Depolymerization rates were between second and third order with respect to the unvolatilized fraction, and the activation energy was 26.3 kcal. Much of the evidence points toward a slow unzipping reaction at the chain ends, but the analysis seems to be complicated by structural variations among the samples.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060520
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  • 88
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    Anisotropy of viscoelastic transitions in oriented polyethylenes (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1083-1091 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Measurements have been made of the anisotropy of viscoelastic behavior in cold-drawn low-density and high-density polyethylene sheets. In the low-density polymer the β transition was shown to be highly anisotropic, maximum losses corresponding to shear on planes containing the axis of drawing and on planes perpendicular to this axis. In high-density polyethylene the α transition shows anisotropy.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060604
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  • 89
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    Thermodynamic properties of poly(2,6-dimethyl-1,4-phenylene ether) (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1141-1148 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The thermodynamic properties of crystalline and amorphous poly(2,6-dimethyl-1,4-phenylene ether) (PPORegistered trademark of General Electric Company. polymer, General Electric Co.) have been studied calorimetrically between 80 and 570°K. The calculated configurational entropy of this polymer, of similar magnitude to other glass-forming liquids, is consistent with the combination of an unusually high ratio of Tg/Tm, and a low melting entropy.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060607
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  • 90
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    Dynamic analysis of branching in radical polymerizationPaper presented at the 154th Meeting, American Chemical Society, Chicago, September 1967. (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1149-1160 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A method for the theoretical analysis of branching in radical polymerization is presented which includes the dynamics of the process. In particular, the method is applied to a polymerization that occurs by decomposition of initiator, propagation, termination by radical combination, and chain transfer with polymer. By a numerical solution of the kinetic equations (suitably transformed), the time dependence of the number-average degree of polymerization (DP), the weight-average DP, the mean number of branches, and the monomer conversion are obtained. The parameters of the process, that is the rate coefficients and initial concentrations, have the following effects: (1) An increase in the chain transfer coefficient increases the ratio of weight-average to number-average Xw/Xn and the mean number of branches Xb, but does not change the number-average Xn. (2) For a given value of the chain transfer coefficient, a change in the parameters of the process such that Xn increases, causes Xw/Xn and Xb to increase also. (3) Chain transfer with polymer seems to produce relatively few polymer molecules having many branches and a large number of smaller polymer molecules having no branches; consequently, the polymer size (or molecular weight) distribution broadens.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060608
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    Skeletal deformation vibrations and rotational isomerism of methylbutenes and methylpentenes as model compounds of 1,4-polyisoprene (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1419-1434 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Infrared spectra of methylbutenes and methylpentenes in the skeletal deformation region have been measured. The force constants for the skeletal deformation vibrations are determined from the frequencies of isobutylene, isobutylene-d6, and methylbutenes. The frequencies of methylpentenes are calculated for the various conformations, and the stable rotational isomers determined. The energy differences between the isomers are determined from the temperature dependence of the spectra. These results are correlated with the conformations of cis-and trans-1,4-polyisoprene chains, and possible conformations are suggested.
    Additional Material: 12 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060802
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  • 92
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    Growth and drawing of polyacrylonitrile crystals grown from solution (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1381-1399 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polyacrylonitrile crystals were grown from dilute solutions of propylene carbonate by a technique similar to that described by Holland et al. Crystals were also grown on various substrates and sampled at various stages of growth after washing away the uncrystallized solution. The initial single lamellae rapidly develop into complex twinned structures with many overgrowths. The morphology of the full-grown crystal varied considerably with crystallization temperature. Small-angle x-ray and electron microscopy results indicate only a small change in lamellar thickness with crystallization temperature for our polymer. Electron and x-ray diffraction results indicate lateral order can be quite good in these crystals. Our x-ray results indicate that the previously reported a and b parameters should be doubled to give a = 21.18 Å and b = 11.60 Å. However, there was no evidence for chain-axis order. The crystals were stretched at various stages of growth on Mylar film. Multilamellar crystals having their long axis parallel to the draw direction formed large cracks perpendicular to the long axis. Fibers of large diameter (100-250 Å) were observed across these cracks. When the long axis of these crystals was at an angle to the draw direction no large cracks or fibers were observed. Single lamellae generally cracked perpendicular to the draw direction, irrespective of their orientation to the draw direction. Definite fibers were not observable across cracks in single lamellae.
    Additional Material: 17 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060714
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    Fast passage dispersion signals in inhomogeneously broadened electron spin resonance spectra: Application to the measurement of the spin-lattice relaxation times of free radicals derived from esters and salts of poly(methacrylic acid) (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1451-1456 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The shape of the first derivative of the dispersion mode of an inhomogeneously broadened electron spin resonance spectrum changes markedly on saturation. This behavior provides a convenient and rapid technique for estimating the spin latice relaxation time of the paramagnetic species involved. The technique is described together with the relevant theory. Values for the relaxation times of free radicals derived from poly(methyl methacrylate) and from poly(sodium methacrylate) have been obtained by this method and are found to be in good agreement with those obtained by the progressive saturation technique. A series of salts of polymethacrylic acid have been γ-irradiated, and the spin lattice relaxation times of the resulting trapped radicals were determined at 77 and 299°K. For a given polymer the relaxation times show little variation with temperature. This is attributed to a broad distribution of correlation times.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060804
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    Tensile strength of rubbers (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1561-1566 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A current theory of the tensile strength of rubbers invokes large-scale crosslink interchange at room temperature to explain the high tensile strengths of networks crosslinked with weak linkages. This mechanical lability of certain crosslinks has been assumed from their known thermal lability at higher temperatures. Relaxation of stress experiments at various elongations have been performed at room temperature on networks crosslinked with both weak and strong linkages. Our purpose was to detect mechanically induced crosslink slippage. We have found no evidence of any mechanical lability of weak crosslinks at room temperature. A hypothesis is presented which explains the high tensile strengths of rubbers crosslinked with weak linkages as resulting from an internally relaxed network formed by the thermal lability of the crosslinks at the vulcanization temperature. This theory is shown to be consistent with some previously unexplained experimental results.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060901
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  • 95
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    Effects of temperature and water on the γ → α crystalline transition of nylon 6 caused by stretching in the chain direction (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1317-1329 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effects of temperature and water on the crystal transition of nylon 6 from the γ phase to the α phase, which is caused by stretching along the chain direction, were investigated. The γ-phase fibers with high crystallite orientation were stretched at constant load under various conditions. An inversion of the effect of water on the transition occurs at about -60°C. Stretching in the wet state is more effective for the transition at higher temperature. In contrast, at low temperatures water in the crystalline regions actsasa cohesive agent for the chains and increases the activation energy for the transition. Thus, dry stretching is more effective than wet stretching at very low temperature. The fraction of transformed α-phase crystallites increases abruptly over a narrow range of stress. Thus the critical stress can be determined for the transition. The critical stress changes appreciably with temperature; the higher the temperature, the lower the critical stress. The relation between stretching temperature and critical stress was analyzed by Flory's equation for the shift of transition temperature by stress. About 220°C. was estimated as the zero-stress transition temperature. The heat content of the γ-phase crystal was estimated to be smaller by 500 cal./mole than that of the α-phase crystal. This result suggests that the free energy of the γ-phase crystal is lower than that of the α-phase crystal at temperatures lower than the transition point. The irreversible strain of a sample in which the crystal transition has taken place is very small at low temperature. This small extension of the sample is evidence that the γ → α transition produced by stretching along the chain axis is a crystal-crystal transition.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/pol.1968.160060709
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  • 96
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    Low-frequency losses in rubbers cross-linked in the presence of diluent (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1371-1379 
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    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Measurements of the complex shear compliance have been made from 0.1 to 7 cycles/sec. and from -5° to 45°C. on several samples of natural rubber cross-linked by dicumyl peroxide in the presence of a diluent oil (volume fraction of rubber, v2, = 0.63 and 0.76) which was subsequently extracted. The properties of the extracted vulcanizates were compared with those having the oil still present and with those of conventional undiluted vulcanizates. Measurements of the diffusion coefficient of radioactively tagged n-hexadecane in trace amounts through the polymer structure were also made both before and after extraction of the oil. The diffusion coefficient was higher in the presence of the oil by an amount consistent with the Fujita theory for concentration dependence of diffusion rate based on free volume considerations. The low-frequency mechanical losses (reduced to 25°C. by the method of reduced variables), as measured by the loss tangent, were shifted to higher frequencies by the presence of oil to a much larger degree than would be expected from the difference in local mobility gauged by the diffusion coefficient. The equilibrium modulus, derived by extrapolation to zero frequency, was diminished by the presence of oil to a greater extent than the factor of v2⅓ expected from the simple theory of rubberlike elasticity. The low-frequency losses in the extracted vulcanizates were smaller than those in conventional vulcanizates with comparable degrees of cross-linking; the differences are attributed to differences in network topology.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060713
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  • 97
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    Relation of the decay of free radicals in irradiated polyethylene to the molecular motion of the polymer and the configurations of the free radicals (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1435-1449 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Decay reactions of the free radicals produced in irradiated polyethylene (high-density and low-density materials) were examined in connection with the molecular motion of the matrix polymer. Three temperature regions, in which the free radicals decay very rapidly, at around 120, 200, and 250°K, were designated TA, TL, and TB, respectively. The decay of the free radicals at these temperatures had activation energies in high-density polyethylene of 0.4 kcal/mole for TA, 9.4 kcal/mole for TL, and 18.4 kcal/mole for TB. In low-density polyethylene these quantities were 0.7 kcal/mole for TA, 23.1 kcal/mole for TL, and 24.8 kcal/mole for TB. Comparison of time constants for the decay reactions and for molecular motion of the matrix polymer indicate that the decay in TA and TB is closely related to molecular motion in the amorphous regions of the polymer. The decay of the free radicals at TL in high-density polyethylene is due to molecular motion associated with local mode relaxation at lamellar surfaces, while that of low-density polyethylene is due to local mode relaxation in the completely amorphous region. Steric configurations of the free radicals which decay in the respective temperature regions were also investigated.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160060803
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  • 98
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    Electronic Resource
    Basic gel permeation chromatography studies. III. Mathematical analysis of peak spreadingPresented at the Fourth International GPC Symposium, Miami Beach, Fla., May 23, 1967. (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1903-1917 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Peak spreading in gel permeation chromatography has been studied with a range of gels including those whose permeation limit corresponded to about 103, 106, 108, and 109 molecular weight polystyrene. Peak spreading conformed to the equation YV2 = YM2 + YA2 + YI2 + YD2 + YS2, where YV is the peak width of a normal chromatogram, YM is the contribution due to the true molecular weight of the sample, YA is due to peak spreading in the apparatus, YI is spreading in the interstitial volume, YD is diffusional spreading due to time spent in the gel, and YS is due to sorption. Evaluating the appropriate parts of the equation leads to measures of the true molecular weight distribution and the contribution due to diffusion into and out of the gel. The data also allowed estimates as to the diffusional spreading with small molecules. With polystyrene having 100 000 molecular weight, diffusional spreading accounts for 80% of YV,2 but with small molecules the contribution due to diffusion was not detected.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160061106
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  • 99
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    Electronic Resource
    Methods of wood chemistry. vol. II. B. L. Browning, Ed., Wiley, New York, 1967. 498 pp. $18.75 (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1943-1944 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160061112
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  • 100
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    Electronic Resource
    Annealing of polybutene-1 single crystals (1968)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 1987-1997 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effects of thermal treatment in the 70-90°C. region on polybutene-1 crystals, prepared by precipitation from dilute pentyl acetate solutions and with lath, hexagonal, and square morphologies, have been studied by using electron microscopy. The stability of polybutene-1 crystals to thermal treatment increases in the order: lath 〈 hexagonal 〈 square. Elucidation of the crystallographic directions in unheated lath crystals with respect to the overall morphology was carried out; evidence for restricted folding in these crystals is discussed.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1968.160061204
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