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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 84 (1962), S. 3971-3972 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 143 (1986), S. 319-324 
    ISSN: 1432-072X
    Keywords: Frankia ; Metabolism ; Propionate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Frankia isolate NPI 0136010 was able to use only propionate and acetate as sole carbon sources and was unable to use hexoses, pentoses, disaccharides, and trisaccharides. Cell free extracts were surveyed for key enzymes of intermediary carbon metabolism. Enzymes of the Embden-Meyerhof-Parnas (EMP) pathway, the tricarboxylic acid (TCA) cycle and glyoxylate shunt were detected while enzymes of the pentose phosphate (PP) and Entner-Doudoroff (ED) pathways were absent. “Malic enzyme” was present allowing for the conversion of malate to pyruvate and gluconeogenesis. Radiorespirometric analysis confirmed the operation of the TCA cycle and established the methylmalonyl pathway as the route of propionate metabolism. The uptake of propionate was active and mediated by sulfhydryl groups.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 10 (1966), S. 259-272 
    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: In order to study structure-tissue reactivity relationships and ultimately develop a less necrotizing adhesive, this laboratory undertook a study of the synthesis and degradation of the homologous series of α-cyanoacrylate monomers and polymers. A method for synthesizing high purity cyanoacrylates and some of their chemical and physical properties and presented. In vitro kinetics studies under heterotgeneous and homogeneous conditions indicate that cyanoacrylate polymers degrade by hydrolytic scission of the polymer chain. The products resulting from such a scission are formaldehyde (positively identified by derivative formation) and ultimately and alkyl cyanoacetate. As the homologous series is ascended, the rate of degradation under neutral conditions decreases. In homogeneous solutions, under alkaline conditions, the ràte of degradation is considerably higher than under neutral conditions and the rates obtained with the methyl to the butyl derivative are of the same order. Aproposed mechanism of degradation is presented. Medical evaluation has indicated that as the homologous series is ascended, the greater the tissue tolerance to the monomers and polymers. The relevance of the results of the in vitro studies to this medical finding is presented.
    Additional Material: 7 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 10 (1966), S. 1214-1214 
    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
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 17 (1973), S. 3509-3514 
    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 glass transition temperatures of the poly(alkyl α-cyanocrylates) were determined by the dilatometric technique, and some of the values were checked by differential thermal analysis. The data indicate that the Tg's appear to decrease with increase in the size of the alkyl group, for a given molecular weight range. It was also found that the Tg of poly(methyl or butyl α-cyanoacrylate) increased with molecular weight. All cyanoacrylates, excepting methyl and ethyl esters, formed only low molecular weight polymers in aqueous surroundings. Therefore, they have characteristic low glass transition temperatures, causing coalescence at low temperatures.
    Additional Material: 3 Ill.
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  • 6
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Methacrylyl-D-alanine, methacrylyl-L-glutamic acid, and acrylyl-L-glutamic acid were homopolymerized or copolymerized with their enantiomorphs in dioxane, aqueous 0.1N HCl, and in water at 90% neutralization of the monomer. The homopolymerization of the optical isomer and copolymerization of racemic mixtures proceeded at identical rates for the first two monomers at 90% neutralization and for methacrylalanine in 0.1N HCl and in butanol, while with methacrylyl glutamic acid in 0.1N HCl the racemic monomer polymerized slightly more slowly than the pure optical isomer. The optical activities of the homopolymers in water varied with the polymerization medium, probably because of differences in the degree of stereoregulation. Optical activities of copolymers prepared from a mixture of the enantiomorphic monomers containing 85% of L and 15% of D isomer were mostly lower than 70% of that of the L homopolymer, which suggests that the growing chain radical has a bias toward an alternation of the steric configurations of the monomer units. Changes in the optical activities of the homopolymers with degree of ionization were compared with the behavior of pivalyl-L-alanine, pivalyl-L-glutamic acid, and isobutyryl-L-glutamic acid. Poly(methacrylyl-D-alanine) behaved in a manner similar to that of its analogue, but the changes in the optical activities of the methacrylyl- and acrylyl glutamic acid polymers followed a complex pattern quite different from that of their analogues. The results were interpreted on the assumption that (1) in the polymer the intrinsically more weakly acidic γ carboxyls ionize first since their ionization leads to a lower charge density than the ionization of α-carboxyl groups and (2) the extension of the polymer backbone affects the optical activity by modifying the conformational distribution in the side chains. It is not believed that, in the cases investigated, helix formation makes an appreciable contribution to the difference between the optical activities of the polymer and their analogues.
    Additional Material: 3 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 5 (1965), S. 227-230 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Proteins and synthetic polypeptides undergo specific catalytic cleavage by enzymes. It is the object of this article to review the specific hydrolytic, redox, and electron transfer reactions involving enzymes and their mechanisms. The stability of the synthetic high polymers in the biochemical environments is much higher than that of proteins in general, but the increasing use of these materials in the field of surgical implants and internal prostheses has necessitated the systematic long range study of the systems in these surroundings. The enzymatic attack on the synthetic polymers has not been the subject of general study until now, but the intimate knowledge of the specificity and mode of attack of the enzymes, in case of the proteins, would pave the way towards experimental designs to elucidate the comparative stability of various synthetic plastics in these environments. The study of the correlation of the mechanical strength and the chemical structures of these polymers tested as implants in living animals is reviewed, and the suitability of several synthetic polymers for this application is discussed.
    Additional Material: 2 Tab.
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  • 8
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 2 (1968), S. 165-171 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: A quantitative method for determining residual ethylene oxide in plastic and rubber catheters using gas-liquid chromatography has been developed. Tests on ethylene oxide stabilized catheters indicated that the amount of ethylene oxide in the catheters decreased as a function of aeration time up to 48 hr. After this period, a steady concentration of ethylene oxide in the catheters appeared to have been reached up to one week's testing.
    Additional Material: 3 Ill.
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  • 9
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: An in vivo method is described for screening polymeric materials for biocompatibility. The test is based on grading acute and subacute tissue reactions at 7 and 28 days, respectively, following implantation in rats. The method is reproducible and reliable. It is designed to provide uniform test criteria for biocompatibility assessment in the early phases of the development of surgical implant materials.
    Additional Material: 8 Tab.
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  • 10
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 12 (1978), S. 43-54 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: An in vitro method has been developed for screening of candidate biomaterials in an early phase of their development. The test is based on L-929 mouse fibroblast cultures and their response to powdered polymer samples. It applies microscopic observation for the detection of morphological changes, uses dye exclusion testing for cell viability determination, and utilizes estimation of population doublings as an end point. The test is shown to be reliable and reproducible and is compared to in vivo implantation studies in rats, previously reported.
    Additional Material: 6 Tab.
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