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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 75 (1953), S. 4341-4341 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Organic molecules found in meteorites seem to have been formed before the meteorites reached ...
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 273 (1978), S. 501-504 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] DSDP site 41–368 in the eastern Atlantic represents an unusual locality, where the behaviour of a short column of organic-rich shale can be studied in relation to the steep thermal gradient imposed by basaltic intrusions. This study indicates that the dominant effects on the measured ...
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 264 (1976), S. 347-349 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Fig. 1 Changes in H/C ratio and percentage C of kerogen when heated. Fig. 2 Relationship between ESR properties of kerogen and its H/C ratio. The sediment sample used has approximately 6% (by dry weight) of organic carbon. The lipid, humic acid and kerogen fractions account for 10, 7 and 72% of ...
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 194 (1962), S. 1098-1099 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] During an investigation of biofractionation patterns of stable sulphur isotopes by micro-organisms4 results were obtained which bear on the problem. The pertinent processes investigated were the oxidation of elemental sulphur by the chemolithotrophic Thio-bacillus concretivorus* and by a ...
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 244 (1973), S. 154-155 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] We obtained a mass spectrum of the ketone using a gas chromatograph coupled with a CEC-21-491 mass spectrometer. The spectrum showed a molecular ion peak at m/e 268 with fragmentation peaks at m/e 250 (M-18); 235 (M-33) ; 225 (M-43) and 210 (M-58). Loss of [CH3-CO]+ and [CH3-CO-CHJ+ gave abundant ...
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Marine biology 100 (1989), S. 185-193 
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The pattern of resource partitioning vs depth by corals collected in February 1983 from Jamaica and the Red Sea was determined from their stable carbon isotope composition. Observations were made on isolated zooxanthellae and corresponding algae-free animal tissue from eight species at four depths over a 50 m bathymetric range. Zooxanthellae δ13C was high in shallow water and became lower as depth increased. This trend correlated significantly with the anual integrated photosynthetic rate. The trend is interpreted according to a “depletion-diffusion” hypothesis; in shallow water, at high rates of photosynthesis, metabolic CO2 is nearly depleted and the supply of CO2 from seawater bicarbonate is limited by diffusion. Since most of the available CO2 is fixed, isotope fractionation is minimal. In deeper water, at lower rates of photosynthesis, metabolic CO2 is ample, and isotope fractionation is greater. Animal tissue δ13C was slightly lower than corresponding zooxanthellae values in shallow water. As depth increased the difference between zooxanthellae and animal tissue δ13C increased and the latter approached the δ13C of oceanic particulate organic carbon. These data suggest that carbon is translocated at all depths and that deep-water corals draw significantly on allocthonous sources of carbon.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Origins of life and evolution of the biospheres 3 (1972), S. 383-403 
    ISSN: 1573-0875
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract A review of the abundance of six biologically important elements (H, C, N, O. P and S) demonstrates that they are present in trace amounts only in lunar matter analysed to date. To the endogenous lunar content, elements are contributed by solar wind irradiation and meteorite impacts. However, it is not yet possible to determine the relative importance of the three sources. Enrichment of the heavy isotopes, C13, O18, S34 suggest that these elements may be lost from the lunar surface by ‘hydrogen stripping’ (from solar wind protons) as volatile gases. The general lack of water, suggests that organic synthesis could not easily be accomplished in lunar rocks. High energy irradiation of the lunar surface may result in rapid destruction of organic matter not protected by a silicate matrix. It is apparent from present data available, that the ambient lunar surface could not support metabolism of known microorganisms.
    Type of Medium: Electronic Resource
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  • 9
    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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