Sökning: "isotopomer"

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

  1. 1. 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

  3. 2. NMR studies of metabolites and xenobiotics : From time-points to long-term metabolic regulation

    Författare :Ina Ehlers; Jürgen Schleucher; Farquhar Graham; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NMR spectroscopy; isotopomer; phospholipid; persistent organic pollutant; CO2 fertilization; photorespiration;

    Sammanfattning : Chemical species carry information in two dimensions, in their concentrations and their isotopic signatures. The concentrations of metabolites or synthetic compounds describe the composition of a chemical or biological system, while isotopic signatures describe processes in the system by their reaction pathways, regulation, and responses to external stimuli. LÄS MER

  4. 3. Multimode resonant X-ray scattering of free molecules

    Författare :Nina Ignatova; Victor Kimberg; Faris Gel’mukhanov; Sergey Polyutov; Hans Ågren; Piero Decleva; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; X-ray absorption spectroscopy; core-excited state; nuclear dynamic; wave-packet; resonant inelastic X-ray scattering; Franck-Condon; water; methanol; water isotopomer; pump-probe; quantum chemistry; ultrafast dissociation; Kemi; Chemistry; Fysik; Physics;

    Sammanfattning : This thesis is focused on the role that nuclear dynamics plays in the formation of X-ray absorption (XAS) and resonant inelastic X-ray scattering (RIXS) spectra of multimode free molecules. A combined approach based on ab initio electronic structure methods and quantum nuclear wave packet dynamics is applied to two systems -- water and methanol in the gas phase. LÄS MER

  5. 4. Quantitation of gluconeogenesis in humans

    Författare :Karin Ekberg; Karolinska Institutet; Karolinska Institutet; []
    Nyckelord :Gluconeogenesis; mass isotopomer distribution analysis; deuteratedwater; hexamethylenetetramine; splanchnic and renal glucose production;

    Sammanfattning : Several methods have been introduced for estimating gluconeogenesis, but none provides a direct measurement without assumptions that condition the accuracy of the estimate. The aim of this work has been to develop a new method for quantitative studies of gluconeogenesis, applicable in humans. LÄS MER

  7. 5. Cholesterol homeostasis in the brain : importance of 24S-hydroxylation

    Författare :Dieter Lütjohann; Karolinska Institutet; Karolinska Institutet; []
    Nyckelord :;

    Sammanfattning : Brain cholesterol is characterized by a very low turnover with very little exchange with lipoproteins in the circulation. We have investigated whether side chain-hydroxylated cholesterol species are important for elimination of cholesterol from the brain. About 80% of 24S-hydroxycholesterol (24S-OH-Chol) present in the body is present in the brain. LÄS MER