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  • Polymer and Materials Science  (22)
  • 31P nuclear magnetic resonance spectroscopy  (1)
  • 32P-postlabelling  (1)
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  • 1
    ISSN: 1432-0428
    Keywords: 31P nuclear magnetic resonance spectroscopy ; skeletal muscle ; glucose metabolism ; fetal growth ; programming
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Thinness at birth is associated with insulin resistance and an increased prevalence of non-insulin-dependent diabetes mellitus in adult life. As muscle is an important site of insulin resistance, and because thin babies have reduced muscle mass, thinness at birth may affect muscle structure and function and impair carbohydrate metabolism. We have therefore used 31P magnetic resonance spectroscopy to investigate the bioenergetics of gastrocnemius and flexor digitorum superficialis muscles in 16 normoglycaemic women who had a low (≤ 23 kg/m3) and 9 women who had a high (〉23 kg/m3) ponderal index at birth. In the flexor digitorum superficialis study anaerobic metabolism was stressed with a constant heavy workload. Low ponderal index subjects fatigued more rapidly (3.3 vs 5.8 min); as phosphocreatine decreased, the accompanying drop in muscle pH was less than in the high ponderal index group. In the first minute of exercise phosphocreatine fell and adenosine diphosphate rose more rapidly (p=0.04 and 0.03, respectively). Gastrocnemius showed a similar trend late in exercise (this exercise was more oxidative, becoming more anaerobic with increasing workload). These changes were not explained by differences in body composition, muscle mass or blood flow. The findings are consistent with a decreased lactic acid and glycolytic adenosine triphosphate production in the low ponderal index group and suggest the possibility that the mechanisms which control substrate utilisation and metabolism in adult life be programmed during prenatal life.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    International archives of occupational and environmental health 62 (1990), S. 467-470 
    ISSN: 1432-1246
    Keywords: PAH ; White blood cell ; DNA adducts ; 32P-postlabelling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary White blood cell DNA adducts were measured in coke workers, local controls and countryside controls using the 32P-postlabelling technique. The method detected aromatic adducts including those formed by polycyclic aromatic hydrocarbons (PAHs). Coke workers are heavily exposed to PAHs particularly when working at the batteries. A difference in adduct levels was noted between the coke workers at the battery as compared to other jobs. The adduct levels in the non-battery were higher than those in the countryside controls.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 21 (1977), S. 1859-1867 
    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: Ultrasonic attenuation and velocity measurements are reported for samples of polycarbonate, polyether sulfone, and polysulfone over a temperature range from 10° to 80°C and over a frequency range from 5 to 35 MHz. Observed relaxations are ascribed to short-range motions of the polymer backbone - here designated the α process. The amplitude of the absorption initially decreased with increasing draw ratio, but after two years returned to the values characteristic of undrawn samples. The longitudinal wave velocity increased with draw ratio in a manner consistent with the creation of molecular order and remained constant over two years. Differences in the attenuation properties between the three polymers studies are discussed in terms of the chemical structure and the macroscopic morphology of the samples.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 21 (1977), S. 319-330 
    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: Measurements are reported on the acoustic attenuation and velocity of dry and wet samples of poly(methyl methacrylate) over a temperature range of 5° to 70°C and over a frequency range of 5 to 35 MHz. Lowering of the glass transition temperature with increase in water content was reflected in an increase in the acoustic attenuation and a lowering of the velocity at high temperature. Comparison of the infrared spectra of wet and dry thin films indicates that water exhibits spectroscopic characteristics of isolated rather than highly clustered molecules. A study of the temperature dependence of the diffusion coefficient of water into the polymer matrix provided an activation energy for the migration process. The data suggest that water plasticizes poly(methyl methacrylate) via specific local interactions with the backbone.
    Additional Material: 7 Ill.
    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 22 (1978), S. 1129-1134 
    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 commercial formulation of thermal antioxidant has been shown to photosensitize the dehydrochlorination of poly(vinyl chloride). The species responsible was shown to be a p-alkyl-substituted phenol, and this was confirmed using p-cresol as a model compound.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 169 (1973), S. 177-189 
    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: Die elektroinitiierte Polymerisation von N-Vinylcarbazol (VCZ) wurde in Aceton bei 25°C mit Zinkbromid als Katalysator unter Verwendung von Platinelektroden eingehend untersucht. Die Polymerisationsgeschwindigkeit erwies sich als direkt abhängig von der Stromstärke, der Zinkbromid-Konzentration und dem anfänglichen Wassergehalt des Solvens.Die Molekulargewichte der entstandenen Polymeren (1000-6000) sind unabhängig von der Stromstärke, der Zinkbromid-Konzentration und dem Umsetzungsgrad des Monomeren zum Polymeren, werden jedoch beeinflußt durch Wasser, die Monomerkonzentration und das Elektrodenmaterial. Die chemische Zusammensetzung der Polymeren ändert sich nicht mit der Stromstärke, der Zinkbromid-Konzentration, dem Umsetzungsgrad und dem Elektrodenmaterial. Sie ändert sich jedoch ein wenig mit dem Wassergehalt des Acetons.
    Notes: The electroinitiated polymerization of N-vinylcarbazole (VCZ) in acetone solvent at 25°C with zinc bromide, as catalyst, and platinum electrodes was investigated in detail. The polymerization rate was found to be directly dependent on current strength, zinc bromide concentration and the initial water content of the solvent.The molecular weights of the formed polymers (1000-6000) are independent of current strength, zinc bromide concentration and degree of conversion of monomer to polymer, but are affected by water, monomer concentration, and by the type of electrodes used. The chemical composition of the polymer is invariant with current strength, zinc bromide concentration, degree of conversion, and electrode material but does vary slightly with the water content of acetone.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 177 (1976), S. 3049-3058 
    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: Bei der elektro- oder fotochemisch initiierten Polymerisation von N,N′-(4,4′-sulfonyldiphenylen)dimaleinsäureimid (4) in Gegenwart von Zinkdibromid und Toluol nehmen die Umsätze linear mit der Bestrahlungs- oder Stromeinwirkungszeit zu. Der Reaktionsmechanismus scheint in einer 2π+2π-Cycloaddition zu bestehen, welcher zu einer Elektro- oder Photo-Kondensation von 4 führt.
    Notes: A study has been made of the electro- and photo-initiated polymerization of N,N′-(4,4′-sulfonyldiphenylene)dimaleimide (4) in the presence of zinc dibromide and toluene. Product yields were linearly dependent on the photo irradiation or current passage times. The reaction mechanism appears to be a 2π+2π cycloaddition resulting in the electro or photo condensation of 4.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 18 (1980), S. 2401-2413 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The considerable potential of high resolution time-resolved spectroscopic data for copolymer systems in elucidation of the intramolecular photophysical processes which occur in polymer systems is illustrated. Such information can not be gleaned solely from studies of homopolymers. Kinetic data and time resolved fluorescence spectra of copolymers of 1-vinylnaphthalene and methyl methacrylate indicate that conventional kinetic schemes are inappropriate for the discription of excimer formation in 1-vinylnaphthalene polymers. Evidence is presented for the presence of an emitting species in addition to the expected monomeric and excimeric forms. The nature of this third species is discussed and photophysical kinetic schemes are proposed to describe intramolecular excimer formation in such systems. Kinetic data have been derived for the principle deactivation pathways through investigation of the observed fluorescence decays upon the intrachain concentration of aromatic species.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The time-resolved fluorescence behavior of polystyrene and a series of styrene-methyl methacrylate copolymers has been examined by using pulsed laser excitation. Although the photophysical characteristics of styrene- and naphthalene-containing polymers may be described by the same general kinetic scheme, some differences in the nature of the photophysical interactions are apparent. Umambiguous evidence for the occurrence of excimer dissociation into excited-state monomer in polymers incorporating styrene chromophores is presented.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The use of pulsed laser excitation upon a series of 1-vinylnaphthalene/methyl methacrylate co-polymers in which the intramolecular chromophore concentration is varied over a wide composition range has allowed the individual rate constants governing intramolecular excimer formation to be determined at various temperatures between 205 and 295 K. Triple exponential functions are necessary for adequate description of the photophysical kinetics over the entire temperature range. It is proposed that the kinetic and temperature behavior is consistent with a kinetic scheme involving two kinetically distinct monomeric species and an excimer in which energy may be transferred from the second monomer M*2 to the first monomer M*1 which can interact with the excimer by a conventional migration mechanism.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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