Search for dissertations about: "Asymmetric migration"

Showing result 1 - 5 of 19 swedish dissertations containing the words Asymmetric migration.

2. 1. Genetic structuring in natural populations - the influence of life history strategies and asymmetric migration

   Author : Lisa Sundqvist; Göteborgs universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Population genetics; Asymmetric migration; Genetic differentiation; Resting stages; Gene flow; Phytoplankton; Macroalgae;

   Abstract : In this thesis I investigate aspects of genetic differentiation and factors influencing the structure of populations. This is done with a special focus on life histories and dispersal strategies common in the marine environment. READ MORE

4. 2. Electronic Energy Transfer within Asymmetric Pairs of Fluorophores: Partial Donor-Donor Energy Migration (PDDEM)

   Author : Stanislav Kalinin; Lennart B.-Å. Johansson; Helge Lemmetyinen; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Physical chemistry; fluorescence resonance energy transfer FRET ; donor-donor energy migration DDEM ; homotransfer; fluorescence relaxation; lifetimes; time-resolved fluorescence anisotropy; time-correlated single photon counting; distance measurements; protein structure; Fysikalisk kemi; Physical chemistry; Fysikalisk kemi; Physical Chemistry; fysikalisk kemi;

   Abstract : A kinetic model of electronic energy migration within pairs of photophysically non-identical fluorophores has been developed. The model applies to fluorescent groups that exhibit different photophysical and spectral properties when attached to different positions in a macromolecule. READ MORE

5. 3. Methods for Asymmetric Olefination Reactions; Development and Application to Natural Product Synthesis

   Author : Daniel Strand; Tobias Rein; Viresh Rawal; KTH; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Antitumor agents; Asymmetric Horner-Wadsworth-Emmons; Desymmetrization; Metal-catalyzed olefination; Mucocin; Palladium-catalyzed allylic substitution; Parallel kinetic resolution; Pyranicin; Pyragonicin; Rhenium; Stereoconvergent synthesis; Stereodivergent synthesis; Stereoselective synthesis; Tetrahydropyran; Wittig reaction; Organic chemistry; Organisk kemi;

   Abstract : This thesis deals with the development and application of methods for asymmetric olefinations, in particular Horner-Wadsworth-Emmons (HWE) reactions, in the synthesis of certain natural products. Relying on asymmetric HWE reactions to access key building blocks, two natu-ral products, pyranicin and pyragonicin, were synthesized from common late intermediates. READ MORE

6. 4. Ruthenium-catalyzed redox reactions and lipase-catalyzed asymmetric transformations of alcohols

   Author : Michaela Edin; Jan-E. Bäckvall; Manfred T. Reetz; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; ruthenium; lipase; catalysis; alcohols; diols; Chemistry; Kemi;

   Abstract : The major part of this thesis describes the synthesis of enantiopure alcohols and diols by combining ruthenium-catalyzed redox reactions that lead to racemization or epimerization and lipase-catalyzed asymmetric trans-formations in one-pot.A mechanistic study of the unexpected facile formation of meso-diacetate products found in enzyme-catalyzed acetylations of alkanediols with Candida antarctica lipase B (CALB) was first performed. READ MORE

7. 5. On the quantitative analysis of electronic energy transfer/migration in proteins studied by fluorescence spectroscopy

   Author : Mikael Isaksson; Lennart Johansson; Bo Albinsson; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Biophysical Chemistry; Biophysical chemistry; Biofysikalisk kemi;

   Abstract : Two recently developed theories of electronic energy transfer/migration were for the first time applied to real protein systems for extracting molecular distances. The partial donor-donor energy migration (PDDEM) is an extension to the previously developed donor-donor energy migration (DDEM, F Bergström et al PNAS 96, 1999, 12477) which allows using chemically identical but photophysically different fluorophores in energy migration experiments. READ MORE