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(Structure and function in photosynthetic membranes and their components). Annual progress report, December 1, 1978-November 30, 1979

Description: Structure and function are being studied in photosynthetic membranes and their components, principally with Rhodopseudomonas sphaeroides. That bacteriochlorophyll (Bchl) can have a strongly shifted absorption maximum in the membrane, without the involvement of excitonic Bchl-Bchl interactions was demonstrated. The orientations of pigments in the membrane are being determined, and the orientations of four distinguishable carotenoid components are under investigation. These studies provide data f… more
Date: January 1, 1979
Creator: Clayton, R.K.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Influence of phase boundaries on photo-induced electron transfer reactions. Final report, July 1, 1977-August 31, 1979

Description: A summary is presented of results of research which was conducted on bipyridyl complexes of ruthenium, with the objective of storing visible light energy. The research covered analytical techniques, synthesis, properties of Ru complexes in monolayers and micelles, and luminescence quenching. 23 references. (DLC)
Date: August 1, 1979
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Ultraviolet and chemical induced DNA repair in human cells assayed by bromodeoxyuridine photolysis or cytosine arabinoside arrest

Description: The bromodeoxyuridine photolysis assay of DNA damage in human cells permits an estimate of both the number of repaired regions in the DNA and the size of the average repaired region - the patch size. The antineoplastic agent arabinofuranosyl cytosine (ara-C) can also be employed to assay the magnitude of repair since this agent appears to block rejoining of single-strand incisions made in the DNA during the initial step of repair. Thus, the number of incisions can be accumulated. The ara-C effe… more
Date: January 1, 1979
Creator: Regan, J.D. & Dunn, W.C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Crossed beam studies of full and half collisions. [F + H/sub 2/(D/sub 2/)]

Description: Results of two experiments performed on a new very high resolution crossed molecular beams apparatus are discussed. The first experiment, photofragmentation of methyl iodide, is deconvoluted to yield vibrational state distributions for the recoiling methyl fragment. These distributions are then analyzed in terms of half-collision models and Franck-Condon factors. The second experiment, a full-collision example, is the reaction of F atoms with H/sub 2/ and D/sub 2/. Laboratory angular and veloci… more
Date: November 1, 1979
Creator: Sparks, R. K.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Photobiological hydrogen production

Description: Hydrogen production by phototrophic organisms, which has been known since the 1930's, occurs at the expense of light energy and electron-donating substrates. Three classes of organisms, namely, photosynthetic bacteria, cyanobacteria, and algae carry out this function. The primary hydrogen-producing enzyme systems, hydrogenase and nitrogenase, will be discussed along with the manner in which they couple to light-driven electron transport. In addition, the feasibility of using in vivo and in… more
Date: January 1, 1979
Creator: Seibert, M; Lien, S & Weaver, P F
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Photochemistry and enzymology of photosynthesis

Description: In the first task, a specially designed mass spectrometer system monitors the gas exchange occurring in response to single short flashes of light. This apparatus will be primarily used to study photosystem II donor reactions, such as the photooxidation of hydroxylamine, hydrazine, and hydrogen peroxide. This technique will also be used to study the light-induced exchange of O/sub 2/ and CO/sub 2/ in algae. The second task, biochemical studies, will focus on the role of chloroplast copper in pho… more
Date: July 30, 1979
Creator: Radmer, R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Experimental investigation of the chemistry of excited states of rare gases. Second quarterly progress report, January 15, 1978-April 15, 1979

Description: The reactions of Kr(/sup 3/P/sub 1/) and Xe(/sup 3/P/sub 1/) with halogen compounds, producing rare gas halides, was studied. Abstracts of two papers on excited rare gas states are included. (DLC)
Date: May 1979
Creator: Setser, D. W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Organic Photochemical Storage of Solar Energy. Progress Report, March 1, 1978-January 31, 1979

Description: Photosensitization mechanisms for driving energy storing reactions of readily available organic compounds have been studied. Aromatic sensitizers were used as complexing agents for a series of non-conjugated dienes which are capable of valence isomerization. Diene exciplexes, shown to be stabilized by electron donor-acceptor interaction, led to photoisomers with high chemical and quantum efficiency in two of the cases studied. For other systems, sensitizer-diene photoaddition reactions were obs… more
Date: February 1, 1979
Creator: Jones, G., II
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Electron Transfer Reactions of Excited Dyes With Metal Complexes. Progress Report, March 1, 1978-February 28, 1979. [Iron-Methylene Blue]

Description: An intense absorption band of /sup 3/MBH/sup 2 +/ at 700nm was characterized in several media and its pK/sub A/ was measured to be 7.17 +- .1 in water. Flash photolysis show that semiethylene blue, MBH/sup +/, formed by quenching /sup 3/MBH/sup 2 +/ with Fe/sub II/(H/sub 2/O)/sub 6//sup 2 +/, decays by disproportionation at a diffusion-controlled rate. Rates of decay of the photostationary state of solutions of MB/sup +/ and Fe/sup II/(H/sub 2/O)/sub 6//sup 2 +/ in acidic media were measured us… more
Date: March 15, 1979
Creator: Lichtin, N. N.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Dissolved organic matter and lake metabolism. Technical progress report, 1 July 1978--30 Jun 1979

Description: Progress is reported in continuing investigations focused on integrated studies of the qualitative and quantitative cycling and metabolism of particulate and dissolved organic carbon in lakes and their inflow sources (surface and subsurface). Emphasis is placed on the sources, fates, and interactions of dissolved and particulate organic matter in relation to: (a) inorganic chemical cycling, (b) allochthonous loading to the lake system, and (c) the coupled nutrient physiology and metabolism of p… more
Date: January 1, 1979
Creator: Wenzel, R.G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Biological solar cells

Description: Recent reports have demonstrated the possibility of employing photoactive, biological membrane components in photoelectrochemical cells. Such systems have produced small photovoltages and photocurrents. Present studies in our laboratories have led to the attachment of a much simpler biological complex, the bacterial photosynthetic reaction center isolated from Rhodopseudomonas sphaeroides, directly onto an SnO/sub 2/ electrode. The light-induced primary charge separation processes which occur a… more
Date: November 1, 1979
Creator: Seibert, M. & Janzen, A. F.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Photoconductivity studies of the ferrocyanide ion under high pressure

Description: The photoaquation of the ferrocyanide ion was studied using a high-pressure photoconductivity apparatus and a steady-state high-pressure mercury lamp. The first-order photocurrent rise-time could be related to the relative quantum efficiency of the photoaquation process, while the dark decay of the photocurrent yielded a relative value of the bimolecular rate-constant for the reverse reaction. Kinetic measurements were carried out on dilute solutions of potassium ferrocyanide in pure water, and… more
Date: January 1, 1979
Creator: Finston, M. I.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Experimental investigation of the chemistry of excited states of rare gases. First quarterly progress report, 15 October 1978--15 January 1979. [Kr* + Cl/sub 2/]

Description: Analysis of XeF(B) and XeF(C) state quenching from photodissociation of XeF/sub 2/ was continued and progress was made on reactive quenching of the resonance states, Xe(/sup 3/P/sub 1/) and Kr(/sup 3/P/sub 1/). The study of the reactions of the resonance states of the rare gases was concentrated on the Kr* + Cl/sub 2/ reaction.
Date: March 1979
Creator: Setser, D. W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Photochemical Determinants of the Efficiency of Photogalvanic Conversion of Solar Energy

Description: A photogalvanic cell is a battery in which the cell solution absorbs light directly to generate species which, upon back reaction through an external circuit with the aid of suitable electrodes, produces electric power; photoactivation of the electrodes is not involved. The charge-carrying species have storage capacity if they are long-lived and can be prevented from engaging in degradative back reactions in bulk solution. The efficiency of a photogalvanic cell for the conversion of photon ener… more
Date: January 1, 1979
Creator: Hoffman, M. Z. & Lichtin, N. N.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Biological consequences of environmental changes related to coastal upwelling: a simulation study

Description: Two simulation models of marine ecosystem dynamics are formulated and applied to field data. The first is a time-dependent model of phytoplankton growth in nutrient-enriched batch cultures where spatial gradients of dependent variables and the effects of higher tropic level processes are not included. Rates of photosynthesis, nutrient uptake, chlorophyll synthesis and cell division for a single phytoplankton functional group are simulated as functions of photosynthetically active solar radiatio… more
Date: May 1, 1979
Creator: Howe, S.O.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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I. Use of m- and p-azidobenzamidines, 4-fluoro-3-nitro-phenylazide, and 3-azido-1,2,4-triazole as photoaffinity probes of tryptic binding site conformation. II. Analysis of tryptophan in proteins by an acidic reaction of 3-diazonium-1,2,4-triazole

Description: Meta- and para-azidobenzamidine have been prepared and evaluated as photoaffinity labels. The compounds inhibit trypsin reversibly in the dark and are competitive with substrate binding. Upon photolysis, irreversible noncompetitive inhibition is observed and is dependent upon concentration, photolysis time, and pH. Specificity of the probes is indicated by experiments in which p-tosyl-L-arginine methyl ester, a trypsin substrate, is used to protect against photoinactivation.
Date: January 1, 1979
Creator: DeTraglia, M.C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Hydrogen as a fuel

Description: A panel of the Committee on Advanced Energy Storage Systems of the Assembly of Engineering has examined the status and problems of hydrogen manufacturing methods, hydrogen transmission and distribution networks, and hydrogen storage systems. This examination, culminating at a time when rapidly changing conditions are having noticeable impact on fuel and energy availability and prices, was undertaken with a view to determining suitable criteria for establishing the pace, timing, and technical co… more
Date: January 1, 1979
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Improved hydrogen photoproduction from photosynthetic bacteria and green algae

Description: Photosynthetic bacteria evolve hydrogen at much higher rates than do other classes of photosynthetic microorganisms. In addition, they tolerate harsh environments, grow rapidly, and utilize both visible and near infrared light in photosynthesis. They do not split water, but this does not necessarily eliminate their potential use in future applied systems. They are easily manipulated genetically, and thus might be modified to metabolize common biomass waste materials in place of expensive define… more
Date: January 1, 1979
Creator: Weaver, P.F.; Lien, S. & Seibert, M.
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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Photobiological production of hydrogen: a solar energy conversion option

Description: This literature survey of photobiological hydrogen production covers the period from its discovery in relatively pure cultures during the early 1930s to the present. The focus is hydrogen production by phototrophic organisms (and their components) which occurs at the expense of light energy and electron-donating substrates. The survey covers the major contributions in the area; however, in many cases, space has limited the degree of detail provided. Among the topics included is a brief historic… more
Date: January 1, 1979
Creator: Weaver, P.; Lien, S. & Seibert, M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Photochemistry of the actinides

Description: It has been found that all three major actinides have a useful variety of photochemical reactions which could be used to achieve a separations process that requires fewer reagents. Several features merit enumerating: (1) Laser photochemistry is not now as uniquely important in fuel reprocessing as it is in isotopic enrichment. The photochemistry can be successfully accomplished with conventional light sources. (2) The easiest place to apply photo-reprocessing is on the three actinides U, Pu, an… more
Date: January 1, 1979
Creator: Toth, L M; Bell, J T & Friedman, H A
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Photobiological hydrogen production

Description: Hydrogen production by phototrophic organisms, which has been known since the 1930's, occurs at the expense of light energy and electron-donating substrates. Three classes of organisms, namely, photosynthetic bacteria, cyanobacteria, and algae carry out this function. The primary hydrogen-producing enzyme systems, hydrogenase and nitrogenase, will be discussed along with the manner in which they couple to light-driven electron transport. In addition, the feasibility of using in vivo and in vitr… more
Date: January 1, 1979
Creator: Seibert, M.; Lien, S. & Weaver, P.F.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Report on the combustion research contractors' meeting

Description: A total of 46 short papers or abstracts are included, arranged into sessions dealing with general and NSLS status, theory of reactivity and chemical dynamics in combustion, kinetics of combustion reactions, (two sessions), and laser diagnostics for high temperature and combustion systems. (DLC)
Date: October 1, 1979
Creator: Klemm, R.B. & Muckerman, J.T. (eds.)
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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