Sökning: "isotopomers"

Visar resultat 1 - 5 av 6 avhandlingar innehållade ordet isotopomers.

  1. 1. Deuterium isotopomers as a tool in environmental research

    Författare :Tatiana Betson; Jürgen Schleucher; Peter Högberg; Richard Robins; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; deuterium; NMR; isotopomers; CO2 response; climate reconstruction; persistent pollutants; stable isotopes; Environmental chemistry; Miljökemi;

    Sammanfattning : This thesis describes the development and the use of quantitative deuterium Nuclear Magnetic Resonance spectroscopy (NMR) as a tool in two areas of environmental research: the study of long term climate-plant interactions and the source tracking of persistent organic pollutant. Long-term interactions between plants and climate will influence climate change during this century and beyond, but cannot be studied in manipulative experiments. LÄS MER

  3. 2. Monitoring climate and plant physiology using deuterium isotopomers of carbohydrates

    Författare :Angela Augusti; Jürgen Schleucher; Vaughan Hurry; Howard Griffiths; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Climate reconstruction; deuterium; elevated CO2; isotopomer; nuclear magnetic resonance; photorespiration; tree-ring cellulose.; Plant physiology; Växtfysiologi;

    Sammanfattning : Climate is changing and it is certain that this change is due to human activities. Atmospheric greenhouse gases have been rising in an unprecedented way during the last two centuries, although the land biosphere has dampened their increase by absorbing CO2 emitted by anthropogenic activities. LÄS MER

  4. 3. Quantum Chemical Calculations on ESR, Core Excitations, and Isotope Effects in Molecular Systems

    Författare :Magnus Jansson; Sten Lunell; Nessima Salhi-Benachenhou; Sven Larsson; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Quantum chemistry; Kvantkemi; Quantum chemistry; Kvantkemi;

    Sammanfattning : In this thesis, quantum chemical calculations are undertaken mostly in order to interpret experimental results, but also to learn about computational techniques, their performance and their limitations. In paper I, the ionization-cleavage process of alkenes is investigated and two pathways are followed, one of initial cleavage and subsequent ionization and on the opposite, the other one of initial ionization and subsequent cleavage. LÄS MER

  5. 4. Applications of Short Extreme Ultraviolet Pulses to the Spectroscopy of Atoms and Molecules

    Författare :Allan Johansson; Atomfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; High-order harmonics; short pulses; pulse characterisation; sidebands; lifetime measurements; time domain spectroscopy; frequency domain spectroscopy; He; N2; CO; XUV; Atomic and molecular physics; relative polarisation; Atom- och molekylärfysik; Fysicumarkivet A:2003:Johansson;

    Sammanfattning : This thesis is devoted to the characterisation in time and frequency, and to spectroscopic application, of extreme ultraviolet (XUV) pulses. High-order harmonic generation or wave mixing processes were used to produce the pulses in the XUV spectral region. LÄS MER

  7. 5. Mass Spectrometric Analysis of Oxylipins : Application to Cytochrome P450-Dependent Metabolism

    Författare :Tomas Nilsson; Ernst Oliw; Johan Bylund; Mikael Hedeland; Uppsala universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; epoxyalcohols; fatty acids; hydroperoxides; electrospray ionization; ichthyosis; CYP4; linear ion trap; fragmentation mechanism; Pharmaceutical pharmacology; Farmaceutisk farmakologi; Biochemical Pharmacology; Biokemisk farmakologi;

    Sammanfattning : Cytochrome P450 (CYP) family 4 constitutes monoxygenases responsible for hydroxylation of fatty acids and other lipids. For example, CYP4F3 metabolizes leukotrienes and CYP4F8 prostaglandin H. Importantly, six of the twelve CYP4 enzymes are orphans, i.e. LÄS MER