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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 2 (1959), S. 192-197 
    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 influences of caustic, zinc, by-product sulfur, and additives on the degree of swelling and the rate of neutralization of viscose are reported. A film technique showed a marked decrease in gel swell factors as the caustic concentration was increased from 5.5 to 7%. In the presence of zinc and by-product sulfur, the viscose additive retards the regeneration process and reduces the gel swell. On mixing various amounts of “white” and conventional viscoses, a minimum value in gel swell occurs with an equal mixture of “white” and regular viscoses. A similar relationship is obtained on adding a polyethylene oxide derivative or an amine to the viscose; namely, a minimum point is reached at 50-70% by-product sulfur, but in these cases as the by-product sulfur is increased to 100%, the gel swell values level off. The actual numerical values of the gel swells are considerably lower for the mixed viscoses which contain additives in comparison with those without an additive. A gradual retardation of the neutralization rate is observed as the amount of by-product sulfur is increased in viscoses containing a polyethylene oxide derivative. A mechanism explaining the retardation of neutralization rates and reduction of the gel swell is proposed, based on the formation of a coordination complex between the additive, zinc ions, by-product sulfur, and the xanthate.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 5 (1961), S. 491-492 
    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: Various chemical additives are commonly used in viscose to reduce the swelling of the resultant fibers and films. It was found that inorganic sodium salts, introduced into the additive-containing viscose, alter the action of the additive. The following salts, listed in order of the values of gel swelling ratios obtained with them, interfere with the deswelling of the viscose during regeneration: citrate 〉 thiosulfate 〉 tartrate 〉 sulfate 〉 chloride = phosphate = thiocyanate 〉 acetate 〉 nitrate 〉 control. Sodium idodide did not affect the usual deswelling of the films, and sodium sulfide and sodium carbonate caused the films to deswell slightly more than the control sample. It was proposed that the effectiveness of the salts follows a Hofmeister or lyotropic series.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The conformation of the acyclic biscystine peptide S,S′-bis(Boc-Cys-Ala-OMe) has been studied in the solid state by x-ray diffraction, and in solution by1H- and13C-nmr, ir, and CD methods. The peptide molecule has a twofold rotation symmetry and adopts an intramolecular antiparallel β-sheet structure in the solid state. The two antiparallel extended strands are stabilized by two hydrogen bonds between the Boc CO and Ala NH groups [N⃛O 2.964 (3) Å, O⃛HN 2.11 (3) Å, and NH⃛O angle 162 (3)°]. The disulfide bridge has a right-handed conformation with the torsion angle CβSSCβ = 95.8 (2)°. In solution the presence of a twofold rotation symmetry in the molecule is evident from the1H- and13C-nmr spectra. 1H-nmr studies, using solvent and temperature dependencies of NH chemical shifts, paramagnetic radical induced line broadening, and rate of deuterium-hydrogen exchange effects on NH resonances, suggest that Ala NH is solvent shielded and intramolecularly hydrogen bonded in CDCl3 and in (CD3)2SO. Nuclear Overhauser effects observed between Cys CαH and Ala NH protons and ir studies provide evidence of the occurrence of antiparallel β-sheet structure in these solvents. The CD spectra of the peptide in organic solvents are characteristic of those observed for cystine peptides that have been shown to adopt antiparallel β-sheet structures.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 29 (1995), S. 1277-1286 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Denture-induced stomatitis is a common intraoral disease which is associated with high levels of Candida albicans adhesion to a denture surface. The aim of this study was to produce a surface-modified denture resin, which is usually manufactured from poly(methyl methacrylate) (PMMA), carrying an immobilized anticandidal protein. PMMA was modified by surface polymerization of methyl methacrylic acid to enhance adsorption of a potent candidacidal salivary protein, histatin 5. The modified PMMA showed higher surface adsorption and desorption of histatin 5 than the unmodified material. Because histatin 5 destabilizes C. albicans cell membranes and allows efflux of intracellular molecules, candidacidal activity was monitored by dye release from fungal cells. Adsorbed histatin 5 did not release dye from the yeast cells; however, dye was detected as histatin was desorbed from the surface. In an adhesion assay, modified PMMA decreased human submandibular-sublingual saliva (HSMSL) mediated adherence of yeast cells to the polymer. Precoating histatin 5 onto unmodified PMMA also abolished HSMSL-mediated adhesion. These experiments show that dental acrylic may be surface modified and loaded with histatin 5 as a means of controlled release of histatin 5 to an affected area. This surface modification may additionally reduce adhesion of C. albicans cells to the saliva-coated material. © 1995 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 49 (1961), S. 241-246 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In a study of isomorphic behavior, it was found that the melting point - composition curve of the copolyamides prepared from caprolactam and p-aminomethylcyclohexylcarboxylic acid was sigmoidal, indicating that the methylcyclohexyl group was interchangeable in the crystal lattice with aliphatic carbon atoms of ω-aminocaproic acid. On the other hand, the benzyl group in the copolymers of caprolactam and p-aminomethylbenzoic acid did not interchange as well, and only partial isomorphism occurred. The analogous meta derivatives, m-aminomethylcyclohexylcarboxylic acid and m-aminomethylbenzoic acid, did not fulfill the spatial requirements of caprolactam. Although V-shaped melting point - composition curves resulted, the disturbance in the crystal network was more severe with the m-phenyl derivative than with the m-cyclohexyl derivative.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Letters 2 (1964), S. 915-919 
    ISSN: 0449-2986
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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