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  • Physics  (27)
  • Golgi apparatus  (1)
  • Wiley-Blackwell  (28)
  • American Chemical Society (ACS)
  • American Institute of Physics (AIP)
  • Oxford University Press
  • 2010-2014
  • 2000-2004
  • 1980-1984  (17)
  • 1975-1979  (11)
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  • Wiley-Blackwell  (28)
  • American Chemical Society (ACS)
  • American Institute of Physics (AIP)
  • Oxford University Press
  • Springer  (2)
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  • 1
    Electronic Resource
    Electronic Resource
    Biochemical and ultrastructural studies of ectoglycosyltransferase systems of murine L1210 leukemic cells (1978)
    New York, N.Y. : Wiley-Blackwell
    Journal of Supramolecular Structure 8 (1978), S. 139-152 
    Details
    ISSN: 0091-7419
    Keywords: sialyltransferase ; galactosyltransferase ; electron microscope autoradiography ; plasma membrane ; Golgi apparatus ; Life Sciences ; Molecular Cell Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Intact murine L1210 leukemic cells incorporated significant quantities of [3H]-N-acetylneuraminic acid directly from CMP-N-acetylneuraminic acid. When pretreated with Vibrio cholerae neuraminidase, incorporation increased sixfold to tenfold. Biochemical studies comparing incorporation of N-acetyl-neuraminic acid from the nucleotide sugar with that from free sugar demonstrated that the relatively high levels of incorporation from CMP-N-acetyl-neuraminic acid could not be due to the incorporation of free sugar generated by extracellular degradation of the nucleotide sugar. Very little N-acetylneuraminic acid was taken up or incorporated by L 1210 cells from free sugar and this incorporation was not increased by neuraminidase pretreatment. Moreover, extracellular breakdown of CMP-N-acetylneuraminic acid during incubations with L 1210 cells was rather insignificant.Electron microscope autoradiography of cells incubated with CMP-N-acetylneuraminic acid demonstrated that greater than 84% of the incorporated radioactivity was associated with the plasma membrane and less than 1% with the Golgi apparatus. These findings are consistent with the conclusion that incroporation of N-acetylneuraminic acid from CMP-N-acetylneuraminic acid is the consequence of a cell surface sialytransferase system. Pretreatment of cells with the nonpenetrating reagent, diazonium salt of sulfonilic acid, significantly inhibited this ectoenzyme system while only marginally affecting galactose uptake and incorporation at the Golgi apparatus. Interestingly, incorporation from CMP-N-acetylneuraminic acid declined as the viability of the cell population declined. When taken together, the above evidence develops a rigorous argument for the presence of a sialyltransferase enzyme system at the cell surface of L 1210 cells.Studies directed towards the detection of a similar ectogalactosyltransferase system were also undertaken. Cells incubated in the presence of UDP-[3H]-galactose incorporated radioactivity into a macromolecular fraction. The presence of excess unlabeled galactose in the incubation medium significantly reduced this incorporation. Electron microscope autoradiographs of cells incubated with UDP-[3H]-galactose, demonstrated that incorporation occurred primarily at the Golgi apparatus. The grain distribution in these autoradiographs was similar to that for free galactose. Thus, the incorporation observed for L-1210 cells incubated in UDP-[3H]-galactose was due primarily to the intracellular utilization of free galactose generated by extracellular degradation of the nucleotide sugar. Inability t o demonstrate an ectogalacto-syltransferase system on L1210 cells does not rule out the possibility that the enzyme is present but undetectable due t o the absence of appropriate cell surface acceptor molecules.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jss.400080204
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  • 2
    Electronic Resource
    Electronic Resource
    Tensile properties of ultradrawn polyethylene (1975)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1177-1186 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: High-density polyethylene filaments prepared by a solid-state deformation in an Instron capillary rheometer show unusually high crystal orientation, chain extension, axial modulus, and ultimate tensile strength. The Young's modulus and ultimate tensile strength have been determined from stress-strain curves. Gripping of this high modulus polyethylene has been a problem heretofore, but the measurement of ultimate tensile strength has now been made feasible by a special gripping procedure. Tensile moduli show an increase with sample preparation temperature and pressure. Values as high as 6.7 × 1011 dyne/cm2 are obtained from samples extruded at 134°C and 2400 atm and tested at a strain rate of 3.3 × 10-4 sec-1. The effect of strain rate and frequency on modulus has also been evaluated by a combination of stress-strain data and dynamic tension plus sonic measurements over nine decades of time.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1975.180130610
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  • 3
    Electronic Resource
    Electronic Resource
    The morphology of ultradrawn polyethylene. I. Nitric acid etching plus gel permeation chromatography (1975)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 2031-2048 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Transparent strands of high-density polyethylene of unusually high c-axis orientation have been produced by a solid-state extrusion, involving pressure, temperature, and deformation, in an Instron capillary rheometer. Measured values for tensile modulus are higher than previously reported for any polyolefin. Previous modulus and electron microscopic data are consistent with a strand morphology comprised (≤20%) of of extended chain crystals. The remainder resembles an oriented fibrillar morphology such as found in highly drawn polyethylene. In the present study, fuming nitric acid etching of the ultraoriented strands, in combination with gel permeation chromatography (GPC), has provided incisive structural information. The strands exhibit ≥3X the resistance to acid degradation shown by conventionally drawn polyethylene. GPC molecular weight distributions (MWD) of etched samples show a single broad peak with a prominent high molecular weight tail. The crystal size, represented by the MWD, is in agreement with the crystal long period determined by small-angle x-ray scattering. The absence of multiple peaks in the etched MWD's is evidence of limited chain folding. The extended chain content, determined from the etched MWD's, is a strong function of strand formation temperature and is in agreement with the fraction of extended chains calculated from modulus measurements.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1975.180131013
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  • 4
    Electronic Resource
    Electronic Resource
    Dimensional changes in ultradrawn polyethylene (1977)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 15 (1977), S. 1427-1434 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Samples of ultradrawn high density polyethylene were studied by thermomechanical analysis. The purpose was to study the dimensional changes in polyethylene morphologies of extreme orientation. Dimensional changes were measured from -140 to +70°C with a precision of better than 1%. A negative thermal expansion coefficient was observed along the length (c axis) of the fibers containing the polyethylene morphologies of extreme orientation. A change in negative coefficient is observed between -35 and -45°C. The sign and magnitude of the expansion coefficient confirm, along with other evidence, the existence of extended chain structures in these morphologies. A series-parallel model has been developed for the ultradrawn polyethylenes to describe the dimensional changes with temperature.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1977.180150809
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  • 5
    Electronic Resource
    Electronic Resource
    Steady-state and dynamic rheology of poly(1-olefin) melts (1978)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 16 (1978), S. 1709-1719 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The steady-state and dynamic melt rheology for a series of poly(1-olefins) has been investigated. The series includes poly(1-butene), poly(1-hexene), poly(1-heptene), poly(1-octene), Poly(1-undecene), poly(1-tridecene), poly(1-hexadecene), and poly(1-octadecene). The flow behavior was investigated by use of a Weissenberg rheogoniometer. Measurements on poly(1-butene) were also made using an Instron capillary rheometer. The empirical relationship developed by Cox and Merz was obeyed for the entire series of poly(1-olefins) at all temperatures investigated. Graessley's theory was used to calculate the flow curves for the poly(1-olefins) from the measured molecular weight distributions. The purpose was to investigate the effect of polymer composition on the shear rate dependence of viscosity. It was found that all experimental flow curves except those for poly(1-hexene) can be fitted with the calculated curves from the individual molecular weight distributions. The conclusion is made that flow curves of poly(1-olefins) depend predominately on molecular weight distribution and are essentially independent of side-chain length even for poly(1-olefins) with pendant groups as long as 16 carbon atoms. The low-shear limiting Newtonian viscosity η0 for all poly(1-olefins) was expressed by, η0 = KM̄w3.4 or by η0 = K′P̄w3.4 where M̄w is the weight-average molecular weight and P̄w is the weight-average degree of polymerization. The K and K′ values obtained decrease systematically as the side chain is increased.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1978.180161001
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  • 6
    Electronic Resource
    Electronic Resource
    Influence of extrusion ratio on the thermal properties and morphology of ultradrawn high-density polyethylene (1978)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 16 (1978), S. 1721-1728 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Solid-state extrusion of high-density polyethylene (HDPE) has received considerable attention. It has been shown that extrudate may have high values of optical clarity, tensile modulus (∼70 GPa = 7 × 1011 dyn/cm2), and c-axis orientation. The effects of extrusion conditions on the properties of the resultant fibers have, however, not yet been clarified. A systematic study has thus been made here to evaluate extrusion pressure, temperature, and extrusion (draw) ratio, and the molecular weight of extruded HDPE. The effects of extrusion ratio on the degree of crystallinity, melting behavior, crystal orientation, and dimensional change along the extrusion direction are reported.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1978.180161002
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  • 7
    Electronic Resource
    Electronic Resource
    Influence of extrusion ratio on the tensile properties of ultradrawn polyethylene (1978)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 16 (1978), S. 1729-1737 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The tensile properties have been evaluated for high-density solid-state polyethylene extruded to different extrusion (draw) ratios. The results are compared with measured and theoretical values on this and other polymers. An extrusion (draw) ratio and a deformation gradient are defined and discussed. The content of extended tie molecules in extruded high-density polyethylene was calculated from a model and modulus data.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1978.180161003
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  • 8
    Electronic Resource
    Electronic Resource
    Morphology of ultradrawn polyethylene strands. II. Nitric acid etching and melting behavior (1975)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 2049-2065 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A transparent, ultraoriented, high-density polyethylene morphology has been produced by solid-state (ultradraw) extrusion in a capillary rheometer. From the perspective of modulus and nitric acid etching behavior, the uniquely high draw ratios (〈325) experienced by the polyethylene during extrusion result in a morphology with a high level of chain extension. The effect of nitric acid etching on strand thermal behavior has been determined by DSC. The observed melting points of unetched strands were sensitive to the thermal contact between sample and sample pan. Under conditions ensuring improved contact, strand superheating is reduced to one-third of previously reported values. The negligible shrinkage evidenced by these strands up to 130° is consistent with the presence of a thermally stable component such as extended chain crystals or crystallized tie chains. The single, high-melting peak is gradually replaced by a nonsuperheating, lower melting peak during the initial stages of acid etch. The resultant peak melting temperature is consistent with the value predicted for the peak crystal thickness of the etched polymer. No evidence is found for a higher melting peak attributable to the extended chain crystalline component. A highly constrained morphology produced by the large tie chain content is believed responsible for strand melting behavior. The melting point of the extended chain crystalline component is reduced by defects and a large ratio of lateral to basal surface area.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1975.180131014
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  • 9
    Electronic Resource
    Electronic Resource
    Thermal expansion of oriented poly(methyl methacrylate) (1983)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 21 (1983), S. 657-665 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The thermal expansivities along (α∥) and perpendicular (α⊥) to the draw direction of poly(methyl methacrylate) (PMMA) with extrusion draw ratios 1 ≤ λ ≤ 4 have been measured between 150 and 298 K. As λ was increased from 1 to 4, α∥ decreased 2-3 times, whereas α⊥ increased only 20-35%. The orientation function f calculated from thermal expansivity using the aggregate model is found to change linearly with birefringence, indicating that each property provides a sensitive measure of molecular orientation. For PMMA, however, only thermal expansivity can give an absolute f, with results at 150 K in reasonable agreement with previous studies using other techniques. At higher temperature, i.e., above ambient, PMMA side-group motions are excited, expanding volume, and calculations based on the aggregate model may not be valid.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1983.180210414
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  • 10
    Electronic Resource
    Electronic Resource
    Solid-state coextrusion of high-density polyethylene. I. Effects of geometric factors (1979)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 17 (1979), S. 2171-2180 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The solid (crystalline) state coextrusion of two high-density polyethylenes (HDPE) having weight-average molecular weights (Mw) of 59,000 and 200,000 have been studied as a function of the geometrical arrangement and the volume fraction of the components. The extrusion rate increased nonlinearly with the volume fraction of the low-Mw, component. The rate was faster when the low-Mw, component was the core rather than the sheath in the initial cylindrical concentric billet. Thus the slow extrusion rate of high-Mw HDPE alone was increased up to ten times by coextrusion with a small fraction of the low-Mw, HDPE component in its center. Generally, the deformation flow profile changed gradually from a parabolic to a W-shaped pattern as the volume fraction of the high-Mw, component increased. However, the geometric arrangement of the two different Mw components also had a pronounced effect on the deformation. The deformation patterns showed that upon coextrusion the low- and high-Mw HDPE's were extruded at the same rate and extrusion draw ratio. The geometrical arrangement had no substantial effects on the tensile modulus and strength of the extrudates; i.e., they increased linearly with volume fraction of the high-Mw HDPE.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1979.180171212
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