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  • 1
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Isotope ratio (IR) mass spectrometry was evaluated for the study of drug metabolism and balance using 13C,15N2- labelled antipyrine (AP) as a test drug. Rats were given 40 mg kg-1 (13C, 15N2)AP intraperitoneally. Breath, urine, faeces and blood were collected. Except for breath, samples were combusted in sealed quartz tubes. The resulting CO2 and N2 were analysed for excess 13C and 15N, relative to pre-dose samples, by IR mass spectrometry. In addition, blood levels of AP and cumulative excretion of urinary AP metabolites were determined by gas chromatography/mass spectrometry/selected ion monitoring (GC/MS/SIM) and high-performance liquid chromatography (HPLC) respectively. Excess 13C and 15N levels in blood were comparable with observed levels of AP, and urinary recoveries of 13C (42%) were in good agreement with those calculated from HPLC data (45%). N-Demethylation, one of the important pathways of AP metabolism, was most rapidly determined by excess 13CO2 excretion in breath (8%). The IR mass spectral analysis complemented gas chromatographic/mass spectrum and HPLC analyses, and was less complex.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 1 (1974), S. 172-174 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Acetic acid isolated from cider vinegar and inorganically synthesized glacial acetic acid have markedly different intramolecular isotopic distributions of the stable carbon isotopes. Carbon-12 is concentrated in the methyl group relative to the carboxyl group in the biologically produced acid. The reverse distribution is observed in the particular sample of glacial acetic acid examined here.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The precise isotopic analysis of carbon by means of differential comparison of CO2 samples is applied to neutral, acid c and basic extract fractions of human urine. It is shown that the standard deviation of the analytical procedure, including sample preparation steps, is about 1% or 0.001 atom % excess carbon-13, but depends some what on the fraction considered. Day to day variations (expressed as standard deviations) in the isotopic composition of the urine fractions are generally less than 2.8%, 1.4% and 3.9% for the neutral, acidica and basic fractions, respectively, although the effect of unusual dietary inputs can be recognized. The ingestion of 23 μg excess carbon-13 in the form of isotopically labelled aspirin is shown to perturb significantly the isotopic composition of the acidic urine fraction which, for a 24 hour collection period, had a mass of 570 mg C. Because only 0.01% of the fraction was consumed by isotopic analysis, further extensive analysis would be possible. It is concluded that carbon-13 tracer experiments generally should be arranged to provide at least 5 × 10-5 g excess 13C/g carbon in any fraction which is to be used for lable detection.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 37 (1986), S. 74-82 
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Corrosion of the alloy AlMg 2 Mn 0,8 in highly-concentrated nitric acidThe purpose of the study was to investigate the corrosion of the alloy AlMg 2 Mn 0.8 in highly-concentrated nitric acid at temperatures between 5 °C and 50°C.The corrosion rates follow the Arrhenius equation \documentclass{article}\pagestyle{empty}\begin{document}$$ \lg \ {\rm w}_{{\rm lin}} = - {\textstyle{{3170} \over {\rm T}}} + 9.1; $$\end{document} the apparent activation energy was calculated to be -60.8 kJ/mol.The ratio of the dissolved alloy components aluminum and magnesium indicates that magnesium had accumulated near the surface of the metal before the exposure to nitric acid. This finding is confirmed by surface analysis.
    Notes: Untersucht wird die Korrosion der Legierung AlMg 2 Mn 0,8 in hochkonzentrierter Salpetersäure bei Temperaturen zwischen 5 und 50°C.Die Abtragungsraten folgen der Arrhenius-Beziehung \documentclass{article}\pagestyle{empty}\begin{document}$$ \lg \ {\rm w}_{{\rm lin}} = - {\textstyle{{3170} \over {\rm T}}} + 9,1; $$\end{document} die scheinbare Aktivierungsenergie ergibt sich zu -60.8 kJ/mol.Aus dem Verhältnis der in Lösung gegangenen Legierungsanteile Aluminium und Magnesium ist abzuleiten, daß Magnesium vor der Salpetersäure-Beanspruchung in der Metalloberfläche angereichert ist. Dieser Befund wird durch oberflächenanalytische Untersuchungen bestätigt.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 130 (1985), S. 155-170 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Aus der Röntgenkleinwinkelstreuung an Legierungen von isotaktischem Polystyrol (iPS) und Poly(2,6-dimethylphenylenoxid) (PPO) wurden Strukturparameter durch Berechnung von Grenzflächenverteilungsfunktionen bestimmt. Es konnte gezeigt werden, daß eine Reihe von Parametern wie die mittlere Dicke von Lamellen und interlamellaren Abständen sowie die Langperiode trotz z. T. großer Unsicherheiten bei der Korrektur der experimentellen Streukurve mit großer Genauigkeit bestimmt werden können. Die aus Grenzflächenverteilungsfunktionen bestimmten Werte wurden mit Ergebnissen aus Modellstreukurvenberechnungen verglichen. Dabei stellte sich heraus, daß theoretische Berechnungen mit einem Modell, das zusätzlich zur kristallinen und amorphen Dichte die mittlere Dichte der Probe berücksichtigt, im wesentlichen dieselben Parameter liefern wie die aus den Grenzflächenverteilungsfunktionen bestimmten.
    Notes: Morphological parameters of isotactic polystyrene (iPS) · poly(2,6-dimethylphenylene oxide) (PPO) blends have been determined from measurements of the small angle X-ray scattering by calculating interface distribution functions. Applied to the compatible system iPS/PPO this method yields a number of reliable parameters such as the long period and mean thicknesses of crystal lamellae and interlamellar spacings. A comparison of the results obtained from the calculation of the interface distribution functions with those derived from model calculations show that theoretical calculations using the density model yield essentially the same results.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 163 (1988), S. 199-204 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Mechanical parameters like Youngs modulus and yield stress have been measured from a set of samples of fiber reinforced polymer composites. The values have been correlated to the lateral diffuse phase boundary thicknesses of the fibers. It has been found, that the phase boundary is an important morphological feature responsible for the transfer of load from the matrix onto the fibers.
    Notes: An aus der orientierten Schmelze kristallisierten, eigenfaserverstärkten Polymerlegierungen aus isotaktischem Polypropylen (iPP) und isotaktischem Poly(1-buten) (PB-1) wurden mechanische Parameter (E-Modul, Fließspannung) gemessen und mit aus äquatorialen Röntgenkleinwinkelstreukurven bestimmten lateralen Grenzschichtdicken korreliert. Die Kurvenverläufe von E-Modul, Fließspannung und Grenzschichtdicke als Funktion der Komponentenzusammensetzung stimmen qualitativ überein. Es wird gezeigt, daß die Morphologie der Grenzschicht von besonderer Bedeutung für die Übertragung der Spannungen von der Matrix auf die Fasern ist.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 157 (1988), S. 165-176 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Aus der Röntgenkleinwinkelstreuung von aus der orientierten Schmelze kristallisierten Legierungen aus isotaktischem Polypropylen und Poly(1-buten) wurden Grenzflächenverteilungsfunktionen berechnet. Die Proben enthalten Nadelkristalle, die in Bezug auf ihre Abstandsverteilung ein „verdünntes System“ darstellen. Es wird gezeigt, daß die Berechnung von Grenzflächenverteilungsfunktionen aus jeweils nur zwei Grenzflächen möglich ist. Der Vergleich der erhaltenen Nadeldicken mit Ergebnissen aus anderen Auswertemethoden ergibt eine gute Übereinstimmung.
    Notes: Interface distribution functions have been evaluated from the equatorial small angle x-ray scattering of blends of isotactic polypropylene and poly(1-butene) crystallized in the shear field of the oriented melt. The samples contain core fibrils which represent a diluted system with respect to their distance statistics. It is shown, that interface distribution functions can be calculated from only two interfaces (diffuse phase boundaries between fibrils and amourphous phase). The calculated thicknesses agree well with values determined from other methods.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0570-0833
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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