3 Matching Results

Search Results

Advanced search parameters have been applied.

Nonphotochemical Hole-Burning Studies of Energy Transfer Dynamics in Antenna Complexes of Photosynthetic Bacteria

Description: This thesis contains the candidate's original work on excitonic structure and energy transfer dynamics of two bacterial antenna complexes as studied using spectral hole-burning spectroscopy. The general introduction is divided into two chapters (1 and 2). Chapter 1 provides background material on photosynthesis and bacterial antenna complexes with emphasis on the two bacterial antenna systems related to the thesis research. Chapter 2 reviews the underlying principles and mechanism of persistent nonphotochemical hole-burning (NPHB) spectroscopy. Relevant energy transfer theories are also discussed. Chapters 3 and 4 are papers by the candidate that have been published. Chapter 3 describes the application of NPHB spectroscopy to the Fenna-Matthews-Olson (FMO) complex from the green sulfur bacterium Prosthecochloris aestuarii; emphasis is on determination of the low energy vibrational structure that is important for understanding the energy transfer process associated within three lowest energy Q{sub y}-states of the complex. The results are compared with those obtained earlier on the FMO complex from Chlorobium tepidum. In Chapter 4, the energy transfer dynamics of the B800 molecules of intact LH2 and B800-deficient LH2 complexes of the purple bacterium Rhodopseudomonas acidophila are compared. New insights on the additional decay channel of the B800 ring of bacteriochlorophyll{sub a} (BChl{sub a}) molecules are provided. General conclusions are given in Chapter 5. A version of the hole spectrum simulation program written by the candidate for the FMO complex study (Chapter 3) is included as an appendix. The references for each chapter are given at the end of each chapter.
Date: June 27, 2002
Creator: Matsuzaki, Satoshi
Partner: UNT Libraries Government Documents Department

Colonial Variations of a Mucoid Strain of Staphylococcus Aureus

Description: It was the purpose of the present investigation to demonstrate the selection of a variant of one strain of Staphylococcus aureus by altering certain environmental factors, and to study that variant as to biochemical activities and capsule formation.
Date: June 1963
Creator: Liston, Winston Bryan
Partner: UNT Libraries

THERMOLUMINESCENCE SPECTRA AND ACTIVATION ENERGIES FOR AROMATIC AMINO ACIDS, TRYPSIN, AND SPORES OF BACILLUS MEGATERIUM

Description: The theory of thermoluminescence is reviewed. The spectral distribution of thermoluminescence and the activation energies associated with peaks of the glow curves were determined for samples of aromatic amino acids, trypsin, and spores of Bacillus megaterium irradiated by a Co/sup 60/ gamma source. All of the substances, except phenylalanine, exhibited a readily observable long-lived glow that persisted up to at least 2 hr following irradiation. Possible reaction mechanisms in the production of thermoluminescence in biological materials are discussed. (C.H.)
Date: June 21, 1963
Creator: Weinberg, C.J.; Carter, J.G.; Nelson, D.R. & Birkhoff, R.D.
Partner: UNT Libraries Government Documents Department