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RADIOISOTOPE AND RADIATION APPLICATIONS QUARTERLY PROGRESS REPORT. SECTION I. USE OF INTRINSIC RADIOACTIVE TRACERS FOR PROCESS CONTROL. SECTION II. RADIATION-INDUCED GRAFT-POLYMERIZATION STUDIES

Description: Research was continued in the areas of intrinsic radioactive tracers for industrial process control and the influence of structural factors in radiation- induced graft polymerization. The use of in-process isotope neutron soarces to produce short-lived radiotraces is discussed. A 10c Po--Be neutron source was obtained for exploratory experiments. The design and construction of a neutronsource storage shield and an activatioa-cell holder are underway. The effect of structural factors oii the eIf… more
Date: October 23, 1961
Creator: McFarling, J.L.; Gluck, P.; Kircher, J.F.; Sunderman, D.N.; Sliemers, F.A.; Luttinger, M. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Artificial photosynthesis using chlorophyll based carotenoid quinone triads: A brief synopsis of research progress as of 31 December 1986

Description: The design, synthesis and study of a series of carotenoid-chlorophyll-quinone triad molecules which mimic some of the basic photochemistry and photophysics of natural photosynthesis is sought. The first members of this series have now been prepared, and have been found to mimic photosynthetic charge separation, carotenoid antenna function, and carotenoid photoprotection from singlet oxygen damage. Although the triad molecules mimic the general principle of multistep electron transfer which is f… more
Date: 1987~
Creator: Gust, Devans & Moore, Thomas A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Photoinitiated electron transfer in multichromophoric species: Synthetic tetrads and pentads featuring diquinone moieties

Description: This project involves the design, synthesis and photophysical study of complex molecular systems engineered to achieve long lived charge separated states by a biomimetic, photoinitiated multistep electron transfer process. The use of these artificial systems to investigate different electron and energy transfer strategies will allow the evolution of more efficient molecular devices for the gathering of light energy and its transformation into chemical potential energy. The three major aspects o… more
Date: April 30, 1992
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Photoinitiated electron transfer in multichromophoric species: Synthetic tetrads and pentads

Description: This research project involves the design, synthesis and study of molecules which mimic many of the important aspects of photosynthetic electron and energy transfer. The knowledge gained from the study of synthetic model systems which abstract features of the natural photosynthetic apparatus can be used to design artificial photosynthetic systems which employ the basic physics and chemistry of photosynthesis to help meet mankind's energy needs. More specifically, the proposed models are designe… more
Date: April 12, 1988
Creator: Gust, J.D. Jr. & Moore, T.A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Photoinitiated electron transfer in multi-chromophoric species: Synthetic tetrads and pentads

Description: This research project involves the design, synthesis and study of the molecules which mimic many of the important aspects of photosynthetic electron and energy transfer. Specifically, the molecules are designed to mimic the following aspects of natural photosynthetic multistep electron transfer: electron donation from a tetrapyrrole excited singlet state, electron transfer between tetrapyrroles, electron transfer from tetrapyrroles to quinones, and electron transfer between quinones with differ… more
Date: February 14, 1990
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Photoinitiated electron transfer in multichromophoric species: Synthetic tetrads and pentads

Description: This research project involves the design, synthesis and study of molecules which mimic many of the important aspects of photosynthetic electron and energy transfer. Specifically, the molecules are designed to mimic the following aspects of natural photosynthetic multistep electron transfer: electron donation from a tetrapyrrole excited singlet state, electron transfer between tetrapyrroles, electron transfer from tetrapyrroles to quinones, and electron transfer between quinones with different … more
Date: April 12, 1989
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Development of Electrochemical Photovoltaic Cells. Second Technical Progress Report, August 1, 1979-October 31, 1979

Description: The development of stable, efficient, photoelectrochemical cells based on silicon and gallium arsenide in non-aqueous electrolyte systems is being investigated. Redox reactions of ferrocene, anthracene and anthraquinone have been studied on platinum and n-silicon electrodes. The latter have been further characterized by differential capacitance measurements. Cells and equipment have been designed and set up for long-term stability studies.
Date: November 21, 1979
Creator: Austin, A. E.; Byker, H. J. & Brooman, E. W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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STUDIES ON THE CHEMICAL AND PHOTOCHEMICAL OXIDATION OFBACTERIOCHLOROPHYLL

Description: A simplified procedure is described for the preparation of crystalline bacteriochlorophyll from R. rubrum. The chemical dehydrogenation of bacteriochlorophyll with quinones is shown to give high yields of 2-desvinyl-2acetyl-chlorophyll a, whereas the photo-oxidation of bacteriochlorophyll results in a mixture of products of which 2-desvinyl-2acetyl-chlorophyll a is only a minor constituent. A number of interesting results have been observed spectrophotometrically during these oxidations under d… more
Date: June 1, 1966
Creator: Smith, John R. Lindsay & Calvin, Melvin
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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BIO-ORGANIC CHEMISTRY QUARTERLY REPORT. June through August,1962

Description: This report covers the following titles: (1) Synthesis of compounds from {sup 14}CO{sub 2} by Chlorella in the dark following preillumination; (2) The effect of oxygen on formation of glycolic acid and other products during photosynthesis by Chlorella; (3) Phosphatase action on phosphoglycolic, 3-phosphoglyceric, and phosphoenolpyruvic acids in spinach chloroplast fragments in the presence and absence of high concentrations of methanol; (4) Absorption spectra of scattering samples. I. An evalua… more
Date: September 26, 1962
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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TRITIUM INCORPORATION STUDIES IN PHOTO-SYNTHETIC BACTERIA

Description: Although the detailed pathway of carbon, by which carbohydrates are formed from carbon dioxide during photosynthesis, has been established, comparatively little is known about the participation and transport of hydrogen in the complex series of reactions now known to be involved in photosynthesis. The transport of hydrogen may occur concurrently with the redox reactions of photosynthetic electron transport leading to the formation of ATP, as well as in the reduction of carbon dioxide. The parti… more
Date: July 1, 1967
Creator: Dehner, Thomas R.; Chan, W.-S.; Caple, Marianne B. & Calvin, M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Magnetic resonance studies of photo-induced electron transfer reactions

Description: During the period covered by this report research has been concerned with the application of Fourier Transform Electron Paramagnetic Resonance (FT EPR) in the study of photo-induced electron transfer reactions. Donor molecules used in this investigation have been various porphyrins, whereas quinones were used as acceptor molecules.
Date: December 1, 1990
Creator: van Willigen, H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Energy transfer processes in solar energy conversion

Description: The program involves the investigation of excitation transport and electron transfer in complex systems. In the area of electron transfer, we have been studying electron back transfer following donor-acceptor photoinduced electron transfer. We are addressing this problem both theoretically and experimentally. In the area of excitation transport, we have been examining transport in solid solutions, liquid solutions, and in clustered excitation transport systems. Again, we are pursuing both exper… more
Date: January 1, 1988
Creator: Fayer, M.D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Energy transfer processes in solar energy conversion

Description: We have made substantial progress in experimental and theoretical studies in two areas: Photoinduced donor to acceptor electron transfer followed by back transfer in random solutions; and electronic excitation transport in systems with complex inhomogeneous spatial geometries and inhomogeneous energy distributions. Through the development of accurate statistical mechanical theories, we have been able to relate dynamics in complex systems to experimental observables. We have then used the experi… more
Date: November 1, 1989
Creator: Fayer, M.D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Chlorophyll photochemistry in condensed media: triplet state quenching and electron transfer to quinone in cellulose acetate films

Description: Chlorophyll a was incorporated into cellulose acetate films and the triplet decay and electron transfer to p-benzoquinone in aqueous solution was studied using laser flash photolysis and ESR. The triplet was found to decay by first order kinetics with the same rate constant regardless of chlorophyll concentration, but the yield was concentration dependent. This is due to quenching at the ground and/or singlet state levels. In the presence of quinone, the triplet is quenched and, when the quinon… more
Date: January 1, 1979
Creator: Cheddar, G.; Castelli, F. & Tollin, G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Spectroscopic study of coal structure and reactivity

Description: Work done during this period (December 15, 1989 to March 14, 1990) covered two of the three primary areas of study of this project. The first involved the continuing development a of step-scanning interferometer for the photoacoustic depth-profiling of materials whose composition varies in the spatial region between 5 and 50 {mu}m from its surface. The second covered the initial construction of an on-line interface between a supercritical fluid chromatograph (SFC) and a Fourier transform infrar… more
Date: September 7, 1990
Creator: Rabenstein, D.L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Magnetic resonance studies of photo-induced electron transfer reactions

Description: Fourier Transform Electron Paramagnetic Resonance (FT EPR) is useful in study of photochemical reactions: a microwave pulse rotates the electron spin magnetization vector from z (magnetic field) into xy plane ([pi]/2 pulse); the time evolution of magnetization in xy plane, the free induction decay (FID), is sampled. Fourier transform of FID gives the frequency domain EPR spectrum of the free radicals, and the method is ideal for time-resolved studies of free radicals produced by pulsed-laser ex… more
Date: November 1, 1992
Creator: van Willigen, H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Environmental effects on electron transfer from chlorophyll triplet to quinone: role of dielectric constant, viscosity and quinone structure in cellulose acetate films

Description: The effects of environmental parameters on chlorophyll triplet quenching and electron transfer to quinones have been investigated in a system consisting of donor and acceptor incorporated into a cellulose acetate film which was subsequently exposed to solvent. Triplet quenching by a diffusional mechanism was found to occur in the dry film, with steric effects being a major determinant of quencher effectiveness. No formation of separated radicals was found under these conditions, probably becaus… more
Date: January 1, 1981
Creator: Cheddar, G. & Tollin, G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Analysis of thermally-stable electron transport factors from the hyperthermophilic archaebacterium Pyrodictium brockii

Description: The mechanisms by which hyperthermophilic archaebacteria grow and carry out metabolic functions at elevated temperatures have yet to be determined. The objective of this work is to develop an understanding of the metabolic characteristics of, and the electron transport enzymes involved in, hydrogen/sulfur transformation by hyperthermophilic archaebacteria. Efforts focus on the autotrophic H{sub 2}-oxidizing bacterium, Pyrodictium brockii which has an optimum growth temperature of 105{degrees}C.… more
Date: September 1, 1992
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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PQQ: Biosynthetic studies in Methylobacterium AM1 and Hyphomicrobium X using specific TC labeling and NMR. [Pyrroloquinoline quinones]

Description: Using TC labeling and NMR spectroscopy we have determined biosynthetic precursors of pyrroloquinoline quinone (PQQ) in two closely related serine-type methylotrophs, Methylobacterium AM1 and Hyphomicrobium X. Analysis of the TC-labeling data revealed that PQQ is constructed from two amino acids: the portion containing N-6, C-7,8,9 and the two carboxylic acid groups, C-7' and 9', is derived-intact-from glutamate. The remaining portion is derived from tyrosine; the phenol side chain provides the … more
Date: January 1, 1988
Creator: Houck, D.R.; Hanners, J.L.; Unkefer, C.J.; van Kleef, M.A.G. & Duine, J.A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Irreversible Adsorption of Phenolic Compounds by Activated Carbons

Description: Studies were undertaken to determine the reasons why phenolic sorbates can be difficult to remove and recover from activated carbons. The chemical properties of the sorbate and the adsorbent surface, and the influences of changes in the adsorption and desorption conditions were investigated. Comparison of isotherms established after different contact times or at different temperatures indicated that phenolic compounds react on carbon surfaces. The reaction rate is a strong function of temperatu… more
Date: December 1988
Creator: Grant, T. M. & King, C. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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TC and H NMR studies of PQQ and selected derivatives. [Pyrroloquinoline quinone]

Description: The ortho-quinone structure of pyrroloquinoline quinone (PQQ) is famous for its reactivity with nucleophilic species of carbon, nitrogen, and oxygen(Duine et. al. 1987). In fact, the crystal structure of PQQ was solved in the form of the C-5 acetone adduct(Salisbury et. al 1979). The propensity of the ortho-quinone to accept nucleophiles is the chemical basis of the function of PQQ at enzyme active sites. The present study focuses on the NMR of PQQ and various derivatives formed with oxygen and… more
Date: January 1, 1988
Creator: Houck, D.R. & Unkefer, C.J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Photochemistry and enzymology of photosynthesis. Progress report, April 1, 1978--August 31, 1978

Description: Progress is reported in the following areas of research: light harvesting and electron transport in C/sub 4/ plants; mass spectrometer studies; measurements in flashing light; spectrophotometric studies; and, redox titration of the plastoquinone pool. (JGB)
Date: August 1, 1978
Creator: Kok, B.; Fowler, C. F.; Golbeck, J.; Radmer, R. J. & Velthuys, B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Photoinitiated electron transfer in multi-chromophoric species: Synthetic tetrads and pentads. Technical progress report, 1987--1990

Description: This research project involves the design, synthesis and study of the molecules which mimic many of the important aspects of photosynthetic electron and energy transfer. Specifically, the molecules are designed to mimic the following aspects of natural photosynthetic multistep electron transfer: electron donation from a tetrapyrrole excited singlet state, electron transfer between tetrapyrroles, electron transfer from tetrapyrroles to quinones, and electron transfer between quinones with differ… more
Date: February 14, 1990
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Energy transfer processes in solar energy conversion. Progress report, January 1, 1988--December 31, 1988

Description: The program involves the investigation of excitation transport and electron transfer in complex systems. In the area of electron transfer, we have been studying electron back transfer following donor-acceptor photoinduced electron transfer. We are addressing this problem both theoretically and experimentally. In the area of excitation transport, we have been examining transport in solid solutions, liquid solutions, and in clustered excitation transport systems. Again, we are pursuing both exper… more
Date: December 31, 1988
Creator: Fayer, M. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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