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  • Chemistry  (3,413)
  • Cell & Developmental Biology  (256)
  • Theoretical, Physical and Computational Chemistry
  • Wiley-Blackwell  (3,669)
  • American Meteorological Society
  • 1975-1979  (3,669)
Collection
Publisher
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Year
  • 1
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Durch direkte Copolymerisation oder durch polymeranaloge Reaktion wurden auf der Basis von Poly[N-(2-hydroxypropyl)methacrylamid] wasserlösliche Copolymere hergestellt, die in Seitenketten farbige Substratgruppen für Chymotrypsin tragen. Substrat war L-Phenylalanin-p-nitroanilid, das über seine Aminogruppe an die endständige Carboxylgruppe der Seitenkette gebunden war. Die Spaltbarkeit des so gebundenen Substrates wurde durch die Michaelis-Konstante, durch die maximale Geschwindigkeit und durch den Prozentsatz an Substrateinheiten ausgedrückt, der für das Enzym zugänglich ist. Hauptsächlich wurde der Effekt der Länge und der chemischen Struktur der Seitenkette untersucht. Es wurde gefunden, daß sie länger als 6 Atome sein muß, daß allgemein die Spaltung durch längere Ketten begünstigt wird. Die ε-Aminocapryl-Gruppe als Seitenkette ist für die Spaltung am günstigsten, Während Seitenketten mit einigen Glycyl-Gruppen obwohl länger weniger günstig sind. Polymere mit einem höheren Gehalt an Substrateinheiten sind besser spaltbar.
    Notes: Water-soluble copolymers based on poly[N-(2-hydroxypropyl)methacrylamide] and bearing in their side chains a chromogenic substrate for chymotrypsin were prepared by direct copolymerization or polymeranalogous reaction. The substrate was L-phenylalanine-4′-nitroanilide linked by its amino group to the terminal carboxylic group of the side chain. The cleavage of the substrate thus bonded, was expressed by means of the Michaelis constant, the maximum velocity, and the percentage of substrate unit accesible to the enzyme. The effect of length and chemical structure of the side chain was investigated in the first place. It was found that the chain must be longer than 6 atoms; longer chains are generally more favourable for this cleavage. The ε-aminocaproyl group provides a chain that is most favourable for the cleavage, whereas chains with several glycyl units, though longer, are less favourable. Polymers with higher content of the substrate units undergo cleavage more readily.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 11 (1978), S. 493-498 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: A series of α-oxobenzimidazolinic merocyanines differently substituted on the ‘phenolate’ part and bearing a paraffinic chain on one heterocyclic nitrogen, has been studied by 13C NMR. Electron donating substituents bring about an increase of the electronic density on the 3 methine carbon and an increase of the alternation of electron density on the 3,4-dimethine bridge. A bathochromic shift of the lower energy electronic transition is also observed. Furthermore, the low field resonance of the 3 methine proton is probably due to a specific interaction between this proton and the ‘phenolate’ oxygen atom. This implies the existence of a favoured trans configuration for merocyanine dyes.
    Notes: Une série de mérocyanines α-oxo benzimidazoliniques diversement substituées sur la partie ‘phénolate’ et possédant une chaǐne grasse sur l'un des azotes hétérocycliques, a été étudiée en RMN du carbone- 13. Des substituants donneurs d'électrons provoquent une augmentation de la densité électronique sur le carbone méthinique C-3 et une augmentation de l'alternance de la distribution de charge sur le pont diméthinique 3,4. Corrélativement un déplacement bathochrome de la transition électronique de plus basse énergie est observé. Par ailleurs, l'apparition de la résonance à champ faible du proton méthinique H-3 semble due à une interaction spécifique intervenant entre ce proton et l'atome d'oxygène ‘phénolate’, ce qui suppose l'existence d'une configuration trans privilégiée pour les mérocyanines.
    Additional Material: 1 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 12 (1977), S. 578-581 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Mass spectrometry has been used in an attempt to resolve the ambiguity in the structures of the isomeric dihydro-oxazin-6-ones and N-acyl-azetidin-2-ones.
    Additional Material: 3 Tab.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 23 (1979), S. 2929-2931 
    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 for staining unsaturated additives within cotton fibers reacts osmium tetroxide with a sorbyl moiety which has been attached to the cellulose chain. Resulting electron micrographs indicate that contrast is considerably enhanced. Measurements of fibrillar size averaged 0.30 nm, closely approximating the values in the literature.
    Additional Material: 2 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 9 (1975), S. 149-155 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Double-loop tendons of fixed and adjustable lengths, and tendons with inner porous tapes both for anastomosis to tendon stumps have been made from readily available materials. By using stainless steel wire and polymer fibers, breakloads have been obtained that range from 20 to 100 lb and elongations have been reduced to less than 2%. Pore sizes up to 50 × 250 μ2 were achieved by using woven, knitted, and braided polyester tapes. For all tendons, Silastic was used to isolate inner fibers and to effect smooth gliding. Preliminary evaluation of these devices, after being implanted in the feet of chickens for 4 weeks, indicates that anastomotic strength of unions formed by use of loops is about 1000 g compared to more than 2000 for unions formed by tissue ingrowth.
    Additional Material: 3 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 10 (1976), S. 311-323 
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The purpose of this investigation was to study bone growth into porous polyethylene rods as a function of time and pore structure. Previous studies have indicated the biocompatibility of solid polyethylene materials which are currently being used clinically. Porous polyethylene rods were implanted in the femurs of mongrel dogs which were sacrificed four, eight, and 16 weeks postoperatively. The implants were then sectioned and examined histologically and microradiographically. Quantitative techniques were employed to determine the amount of bone ingrowth as a function of time and pore size. The pore structures of the materials were evaluated using optical microscopy and mercury intrusion porosimetry.The results of this investigation have demonstrated that porous polyethylene is capable of accepting bone growth into pores as small as 40 μm. The optimum rate of bone ingrowth was observed in pore sizes of approximately 100 to 135 μm, with no increase in the rate of bone ingrowth observed in samples possessing larger pore sizes. No adverse tissue response was found at implant times up to 16 weeks in pore sizes of 100 μm or larger.
    Additional Material: 4 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 85 (1975), S. 321-329 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Low (5 × 10-9 M to 10-7 M) acetylcholine concentrations cause a calcium-independent stimulation of the initiation of DNA synthesis and proliferation of lymphoblasts which are part of rat thymocyte populations suspended in vitro. A much higher (5 × 10-5 M) acetylcholine concentration also stimulates lymphoblast DNA synthesis and proliferation, but this action is calcium-dependent. This proliferogenic response to acetylcholine is however not clearly mediated by either cyclic GMP or cyclic AMP.
    Additional Material: 9 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 5 (1978), S. 498-507 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The major metabolic pathway of the (-) enantiomer and the (+) enantiomer of 2-hydroxy-N-cyclopropylmethylmorphinan in dogs was shown to be conjugation with glucuronic acid and/or sulfate. Gas chromatography mass spectrometry, nuclear magnetic resonance spectroscopy and X-ray crystallography were used to identify additional metabolites of the two enantiomers in dog urine after hydrolysis with Glusulase. Metabolites of the (-) enantiomer were identified as 2-hydroxymorphinan and 2,7β-dihydroxy-N-cyclopropropylmethylmorphinan. The major metabolites of the (+) enantiomer in hydrolyzed dog urine were identified as 2-hydroxymorphinan, 2,3-dihydroxy-N-cyclopropylmethylmorphinan and 2-methoxy-3-hydroxy-N-cyclopropylmethylmorphinan. In addition, tentative or partial structures were postulated for three minor metabolites of the (+) enantiomer: 2-methoxy-3-hydroxymorphinan, a metabolite containing a hydroxyl group on either carbon 4, 5, 6 or 7 and a methylated catechol metabolite containing a hydroxyl group on carbon 4, 5, 6 or 7. Thus, the major oxidative pathways of the (-) enantiomer were N-dealkylation and aliphatic hydroxylation, while the (+) enantiomer mainly underwent N-dealkylation and aromatic hydroxylation, followed by phenolic methylation. Analysis of urine from a human subject administered the (-) enantiomer suggested that the metabolism of this isomer by man was similar to its metabolism by dog.
    Additional Material: 9 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 8 (1979), S. 259-264 
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Raman and infrared spectra of difluorophosphine and difluorophosphine-d1 in the gaseous and solid phases from 100 to 3000 cm-1 have been recorded. The six fundamental frequencies have been assigned on the basis of group frequencies, depolarization ratios, band types and isotopic shifts. A normal coordinate analysis was carried out. Very little mixing was found to occur between the normal modes. Thermodynamic functions were calculated from the observed frequencies and previously reported moments of inertia.
    Additional Material: 5 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 657-661 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Copolymers of N-vinylcarbazole (VCZ) with methyl methacrylate (MMA) and styrene (ST) were prepared using doubly-labelled benzoyl peroxide as initiator and the relative numbers of benzoyloxy and phenyl end-groups were determined. In the copolymers containing MMA, the ratios of the two types of end-group are those expected for products of free radical polymerization. The copolymers of VCZ with ST contain benzoyloxy and phenyl end-groups in proportions which correspond to those found in homopolymers of VCZ made in non-radical polymerizations promoted by the peroxide.
    Additional Material: 2 Ill.
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