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  • Polymer and Materials Science  (12)
  • axon  (1)
  • Wiley-Blackwell  (13)
  • Institute of Physics
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 9 (1988), S. 48-59 
    ISSN: 0886-1544
    Keywords: axon ; growth cone ; retraction ; taxol ; slow transport ; axonal transport ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Axons in tissue culture retract and shorten if their tips are detached from the substrate. The shortening reaction of the axon involves contractile forces that also arise during normal axonal motility, elongation, and retraction. We studied shortening in axonal segments isolated from their parent axons by transecting the axon between the growth cone and the most distal point of adhesion to the substrate. Within 15-20 minutes after transection, an isolated axonal segment shortened and pulled its tail end toward the growth cone. During the shortening process, long sinusoidal bends arose along the axon. The identical shortening reaction occurs without transection, when the axon tip is detached from the substrate. Pharmacological studies with inhibitors of glycolysis indicate that the shortening mechanisms utilize metabolic energy, presumably ATP. The rate of sinusoidal shortening is similar to both the rate of polymer translocation in the axon by slow axonal transport and the rate of normal axonal elongation. Taxol inhibits the shortening reaction with a similar dose dependence to its inhibition of axonal growth. Together, all these observations suggest that the same basic intracellular motility mechanisms are involved in normal axonal growth, in slow axonal transport, and in the shortening reaction: the intracellular dynamic system that utilizes ATP to generate longitudinal movements of polymers within the axon may be the same mechanism underlying both the retraction and the elongation of the axon.
    Additional Material: 9 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 23 (1979), S. 3553-3561 
    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 method for the determination of composition and content of pendent double bonds in untreated samples of styrene-ethylene dimethacrylate and styrene-divinylbenzene copolymers from Raman spectra has been developed. By computer treatment of spectra it was shown that Raman spectra are sensitive to the distribution of components in the studied copolymers.
    Additional Material: 4 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 14 (1976), S. 1789-1800 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: From the temperature dependence of integrated intensities and from line widths in high-resolution 1H-NMR spectra, the relaxation times T1 and T2 of protons in CH2 and CH3 groups of polyisobutylene in CCl4 solution have been determined. Although the relaxation time T1 of methylene protons is determined mainly by intragroup interactions, intergroup interactions of two methyl groups from each two consecutive monomer units were found to contribute considerably to T1 of methyl protons. The Structure and mobility of polyisobutylene (PIB) molecules in solution is discussed on the basis of the relaxation time data.
    Additional Material: 5 Ill.
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  • 4
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Mittels 1H- und 13C-NMR- sowie Ramanspektren wurde gezeigt, daß die Epoxidgruppe von 2,3-Epoxypropylmeth-acrylat (EPMA) in Gegenwart einer großen Glasoberfläche quantitativ gespalten wird, wobei es zur Bildung von 2,3-Dihydroxypropylmethacrylat und einer Reihe von niedrigmolekularen Substanzen mit Doppelbindungen kommt. Die Polymerisation von EPMA in Gegenwart von porösem Glas liefert Poly(2,3-epoxypropyl-methacrylat). Ein Teil dieses Polymers ist am Glas fest gebunden, wahrscheinlich über die Zerlegungsprodukte des EPMA.
    Notes: From 1H- and 13C-NMR and Raman spectra it was found that by the presence of a large surface of glass, the epoxide group of 2,3-epoxypropyl methacrylate (EPMA) is completely decomposed, yielding 2,3-dihydroxypropyl methacrylate and a number of additional low-molecular-weight products with double bonds. Polymerization of EPMA in the presence of porous glass yields poly(2,3-epoxypropyl methacrylate). Part of this polymer is firmly bound to the glass, probably by means of the decomposition product of EPMA.
    Additional Material: 8 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Acta Polymerica 36 (1985), S. 645-648 
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Untersucht wurden 1H-FID- und MW4-Spektren vom mit Ethylendimethacrylat und Divinylbenzen vernetztem und mit CCl4, CDCl3 und Benzen gequollenem Polystyren. Die mit Hilfe von Vielimpulscyclen erreichbaren Linienverschmälerungen werden diskutiert und mit denen der MAR-Technik verglichen. Die Temperaturabhängigkeit der effektiven Relaxationszeit T2eff spiegelt die Dynamik lokaler Segmentprozesse wider.
    Notes: 1H-FID and MW4-pulse spectra of polystyrene crosslinked with ethylene dimethacrylate or divinylbenzene and swollen in CCl4, CDCl3 or benzene, are measured. Line-narrowing effects of multiple-pulse sequences are discussed and compared with those of the MAR-technique. The temperature dependence of the effective relaxation time T2eff reflects the dynamics of local segmental processes.
    Additional Material: 5 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Letters 4 (1966), S. 645-651 
    ISSN: 0449-2986
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 12 (1974), S. 349-353 
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Letters 3 (1965), S. 213-219 
    ISSN: 0449-2986
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 20 (1982), S. 1623-1632 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Association of syndiotactic (s) poly(methyl methacrylates) (PMMAs) in toluene, benzene, and acetonitrile has been studied by NMR spectroscopy, osmometry, and viscometry. It was found that in solutions of highly syndiotactic PMMA in toluene, most of the polymer exists in the associated state. Association takes place by means of stereospecific intermolecular and intramolecular interactions of long parallel syndiotactic sequences. The minimum length of syndiotactic sequences necessary for association of s-PMMA in toluene is 7-8 monomer units. Viscosity data indicate that in dilute solutions the associated structures appear as large formations which do not have the character of compact particles. The formation of the aggregates of PMMA is a relatively slow process. A model of the structure of the aggregates of s-PMMA in toluene is proposed. As compared with that in toluene, the tendency to aggregation in benzene and acetonitrile is negligible. Integral parameters currently used for the characterization of polymer-solvent interaction, like “good” or θ solvent, are not suitable for predicting the tendency of s-PMMA to aggregation. The formation of aggregates evidently has some connection with the effect of the solvent upon the conformational structure of syndiotactic sequences.
    Additional Material: 7 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 22 (1984), S. 617-635 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: From analysis of infrared spectra it was found that in syndiotactic (s) poly(methyl methacrylate) (PMMA) in solution, long s sequences contain an increased population of diads with a skeletal conformation tt (in the staggered approximation). Self-aggregation of s-PMMA in solution leads to a further increase of the fraction of long s sequences in the extended chain conformation, and to an ordering of easter groups. When solid s-PMMA is isolated from a solution in which it exists in the aggregated state, these characteristics are preserved in the solid. The polymer appears partially crystalline by x-ray scattering, and it exhibits fibrillar morphology under the electron microscope. Ordered structures of s-PMMA melt at temperatures about 150°C, while the presence of residual solvent decreases the temperature of melting. Solid s-PMMA obtained from solutions in which aggregation of the polymer does not take place, like s-PMMA which did not come into contact with solvent, contains a higher proportion of syndiotactic diads with a skeletal conformation tg; these samples are amorphous and morphologically structureless. Analogies between the structure of ordered s-PMMA and the structure of the PMMA stereocomplex are also discussed.
    Additional Material: 10 Ill.
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