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Visar resultat 1 - 5 av 12 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Catalysts for Oxygen Production and Utilization : Closing the Oxygen Cycle: From Biomimetic Oxidation to Artificial Photosynthesis

    Författare :Erik Karlsson; Jan-Erling Bäckvall; Björn Åkermark; Jerker Mårtensson; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; oxygen; catalytic oxidation; biomimetic oxidation; artificial photosynthesis; water oxidation; DFT calculations; Organic chemistry; Organisk kemi; organisk kemi; Organic Chemistry;

    Sammanfattning : This thesis describes the development and study of catalysts for redox reactions, which either utilize oxygen or hydrogen peroxide for the purpose of selectively oxidizing organic substrates, or produce oxygen as the necessary byproduct in the production of hydrogen by artificial photosynthesis.The first chapter gives a general introduction about the use of environmentally friendly oxidants in the field of organic synthesis, and about the field of artificial photosynthesis. LÄS MER

  3. 2. Effects of Protons and Small Alcohols on the Oxygen-Evolving Complex of Photosystem II

    Författare :Paulina Geijer; Biokemi och Strukturbiologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; EPR; pH; methanol; S3; S2; S0; YZ; Mn cluster; Oxygen-evolving complex; S-states; Biochemistry; Metabolism; Biokemi; metabolism;

    Sammanfattning : Higher plants and algae use oxygenic photosynthesis to convert solar energy to reducing equivalents and chemical energy. The ultimate electron donor to oxygenic photosynthesis is water. Oxidation of water to oxygen occurs in the oxygen-evolving complex (OEC) in Photosystem II (PSII). The OEC is composed of four Mn atoms, Ca2+ and Cl-. LÄS MER

  4. 3. Substrate water binding to the oxygen-evolving complex in photosystem II

    Författare :Håkan Nilsson; Johannes Messinger; Wolfgang Schröder; Robert L. Burnap; Umeå universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Photosynthesis; Photosystem II; water oxidation; oxygen evolution; substrate water exchange; membrane-inlet mass spectrometry;

    Sammanfattning : Oxygenic photosynthesis in plants, algae and cyanobacteria converts sunlight into chemical energy. In this process electrons are transferred from water molecules to CO2 leading to the assembly of carbohydrates, the building blocks of life. LÄS MER

  5. 4. Photosynthetic Oxygen Evolution - EPR studies of the manganese cluster of photosystem II

    Författare :Sindra Peterson Årsköld; Biokemi och Strukturbiologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; S2 state; second cycle; Biochemistry; Metabolism; Biokemi; metabolism; S0 state; light-adaptation; pulsed EPR; methanol; relaxation; microwave power saturation; S-cycle; Oxygen-evolving complex; Water-oxidizing complex;

    Sammanfattning : In this thesis, a new electron paramagnetic resonance (EPR) signal from photosystem II is presented. The signal is shown to originate from the S0 oxidation state of the oxygen-evolving complex (OEC). LÄS MER

  7. 5. Oxidation and reduction reactions of the water-oxidizing complex in photosystem II

    Författare :Long Vo Pham; Johannes Messinger; Imre Vass; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Photosystem II PSII ; oxidation; reduction; flash induced oxygen evolution pattern FIOP ; water; oxygen; global fitting program GFP ; thylakoids; fysikalisk kemi; Physical Chemistry;

    Sammanfattning : The oxygen that we breathe and food that we eat are products of the natural photosynthesis. Molecular oxygen is crucial for life on Earth owing to its role in the glycolysis and citric acid pathways that yield in aerobic organisms the energy-rich ATP molecules. LÄS MER