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Radiation effects and metalloproteins studied by x-ray photoelectron spectroscopy

Description: X-ray photoelectron spectroscopy (XPS) is used to study the bonding structure at the iron site of cytochrome c and the bonding of rare earth ions to the phosphate oxygens of ATP. Radiation effects are studied on several amino acid and simple peptide model systems. The emission spectrum of the x-ray source is calculated from literature references. The distributions of photon energy as a function of photon frequency and as a function of take-off angle are obtained. From these distributions, the r… more
Date: July 1, 1975
Creator: Wurzbach, J.A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Larvae and juveniles of the brook silverside, Labidesthes sicculus

Description: Protolarvae have 6 to 7 preanal and 29 to 31 postanal myomeres. Migration of the anus and pelvic buds during the metalarval phase results in 14 to 15 preanal and 24 to 25 postanal myomeres and causes a relative increase in prepelvic body length. Pectoral fins in protolarvae appear before finfold differentiation. Median fin ray development in mesolarvae appears sequentially in the caudal, anal, and soft dorsal fins, respectively. The spinous dorsal and pelvic fins differentiate in metalarvae. Pr… more
Date: January 1, 1978
Creator: Freitsche, R. A.; Miracle, R. D. & McFarlane, R. W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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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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Isolated photochemical reaction centers from bacteriochlorophyll b - containing organisms

Description: Optical, ESR and pulsed laser spectroscopic examination of isolated bacteriochlorophyll (BChl) b-containing reaction centers (RCs) demonstrates that their composition (1 P960 : 2 bacteriopheophytin (BPh) b : 2 cyt c 558 : 2 cyt c 553 : BChl/BPh = 2) and their mechanism for charge separation are very similar to those in BChl a-containing RCs; however, P960/sup +/, the oxidized form of the primary electron donor, is apparently not a symmetrical dimer of BChl b. The ''primary'' electron acceptor (… more
Date: January 1, 1977
Creator: Thornber, J.P.; Dutton, P.L.; Fajer, J.; Parson, W.W.; Prince, R.C.; Tiede, D.M. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Energy transfer and utilization in biological systems. Final report, September 1, 1967--September 15, 1976. [Fluorescence studies of photosynthesis]

Description: In fluorescence studies of the photosynthetic process it was shown that the photosynthetic rate and light loss via chlorophyll fluorescence are strictly complementary. The exciplex state of matter responsible for most photochemistry was discovered and a wide variety of information about the state gained from studies of indole exciplexes. In addition to the nature of the bonding, degree of stability and general excited state behavior of indole exciplexes, their ability to lose electrons in a hig… more
Date: March 1, 1978
Creator: Lumry, R.W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Application of foams to the processing of fabrics. Final report, October 1, 1977-September 30, 1979

Description: In mill trials, a range of foam fabric finishes including softeners, hand builders, and durable-press and shrink-resistant types were applied to cotton sheeting, corduroy, and polyester/cellulosic blends, etc. In all cases, substantial energy savings were realized. A number of companies are currently using foam fabric finishing as a commercial production process. Additionally, the pilot range has been used to demonstrate foam fabric finishing to over twenty companies. The range has been used to… more
Date: December 1, 1979
Creator: Duke, M.W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Selective paint and black chrome coatings development. Semiannual report, June 5-December 5, 1978

Description: Solar selective black chrome and paint coatings were investigated to improve their performance and to develop techniques for large-scale applications. Formulations and processing conditions for thickness sensitive paint coatings were defined which consistently provide solar absorptance (..cap alpha..) of 0.90 and emittance (epsilon) of 0.10 on low emittance substrates. A significant improvement in abrasion resistance was achieved by decreasing the pigment volume concentration. Addition of alumi… more
Date: December 1, 1978
Creator: Lin, R J.H. & Zimmer, P B
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Determination of structural water by neutron protein crystallography: an analysis of the carbon monoxide myoglobin water structure

Description: An ideal technique for studying the water structure of proteins using neutron crystallography is discussed. The advantages of using deuterons (D/sub 2/O) instead of hydrogen (H/sub 2/O) are explained. The results of an early unrefined met myoglobin neutron analysis are presented. More recent high resolution x-ray analysis of met myoglobin and refined neutron analysis of carbon monoxide myoglobin water structure were compared. Neutron maps were included.
Date: January 1, 1979
Creator: Schoenborn, B. P. & Hanson, J. C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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SPECTROSCOPIC INVESTIGATION OF THE INHIBITORY EFFECT OF FATTYACIDS ON PHOTOSYNTHETIC SYSTEMS

Description: Fatty acids have a reversible inhibitory effect on respiration and on photosynthetic action. They investigated the influence of octanoic acid on the photosynthetic bacteria Rhodopseudomonas spheroids R-26. From the spectroscopic data they conclude that a less efficient energy transfer and decoupling of the light harvesting pigment system from the energy converting reaction center is responsible for the inhibitory effect.
Date: May 1, 1971
Creator: Steffea, Hans & Calvin, Melvin.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Excited state electron transfer in systems with a well-defined geometry. Progress report, May 1, 1979-April 30, 1980

Description: To determine what are the important criteria governing efficient light-induced electron transfer, we have been studying cyclophanes formed by joining two chlorophyll macrocycles together with two covalent linkages. The properties of the cofacial dimer can be altered by adding one or two magnesium atoms. When a cyclophane containing only one metal atom is excited electron transfer takes place in under ten picoseconds. Evidence for the formation of a state having a great deal of charge transfer i… more
Date: December 1, 1979
Creator: Kaufmann, K.J.
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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Quatenary structure of methemoglobin II. Pulse radiolysis study of the binding of oxygen to the valence-hybrid. Progress report, December 1, 1978-November 30, 1979

Description: The pulse-radiolysis of solutions of adult human methemoglobin was used in order to reduce a single heme-iron within the protein tetramers. The valence-hybrids thus formed were reacted with oxygen. Kinetics of the reactions were studied. The effects of pH and inositol-hexaphosphate were examined. The kinetics of the ligation of oxygen to stripped valence-hybrids showed a single-phase behavior at the pH range 6.5 to 9. As the pH was lowered below 6.5 a second, slower phase became apparent. In th… more
Date: January 1, 1979
Creator: Chevion, M; Ilan, Y A; Samuni, A; Navok, T & Czapski, G
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Investigation of the Triplet State of Chlorophylls. Technical Progress Report, May 1, 1978--April 30, 1979

Description: The photoexcited triplet state properties of chlorophyll dimer systems in vitro were investigated by zero-field optically detected magnetic resonance (ODMR) spectroscopy at 2/sup 0/K. Measurements of the triplet state zero-field splittings, overall triplet lifetimes, and individual spin sublevel intersystem crossing rate constants were obtained for solutions of chlorophyll a and zinc-substituted chlorophyll a and for the covalently linked dimeric derivative of pyrochlorophyllide a. The triplet … more
Date: January 1, 1979
Creator: Clarke, R. H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Partitioning of electrostatic and conformational contributions in the redox reactions of modified cytochromes c

Description: The reduction of acetylated, fully succinylated and dicarboxymethyl horse cytochromes c by the radicals CH/sub 3/CHOH, CO/sub 2/, O/sub 2/, and e/sup -//sub aq/, and the oxidation of the reduced cytochrome c derivatives by Fe(CN)/sub 6//sup 3 -/ were studied using the pulse radiolysis technique. Many of the reactions were also examined as a function of ionic strength. By obtaining rate constants for the reactions of differently charged small molecules redox agents with the differently charged c… more
Date: January 1, 1979
Creator: Ilan, Y; Shafferman, A; Feinberg, B A & Lau, Y K
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Dichloromethane as a modulator of hemoglobin function. [Low angle neutron scattering studies on dichloromethane-hemoglobin complex]

Description: X-ray crystallographic analysis suggested that site D3 is only fully occupied at dichloromethane (DCM) pressure of 200 Torr while the DCM dependent oxygenation curve measured by spectroscopic techniques suggests the DCM sites which affect the allosteric equilibrium are fully occupied at 75 Torr. To determine whether the difference is explainable by DCM binding differences between crystalline and noncrystalline hemoglobin, the DCM-hemoglobin complex was studied by low angle neutron scattering in… more
Date: January 1, 1978
Creator: Schoenborn, B P & North, B E
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Biomimetic approach to solar energy conversion: artificial photosynthesis

Description: Results of efforts to devise apparatus and systems for using solar energy for chemical purposes by methods that mimic those used by photosynthetic organisms are reported. Sufficient progress has been made in the understanding of plant photosynthesis to make artificial photosynthesis a reasonable goal. Artificial photoreaction centers, the apparatus used by photosynthetic organisms for light energy conversion to chemical oxidizing and reducing capacity, have been made in the laboratory. The synt… more
Date: January 1, 1978
Creator: Katz, J.J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Orientation of the hemes of high potential cytochromes relative to photosynthetic membranes, as shown by the linear dichroism of oriented preparations

Description: The orientations of high potential cytochromes with respect to photosynthetic membranes was investigated in spinach chloroplasts and in Rhodopseudomonas viridis. The general approach consists of detection with polarized light of photoinduced absorbance changes related to the oxidation of the cytochromes. The orientation of cytochrome c/sub 558/ was measured at room temperature in chromatophores and whole cells of Rp. viridis, oriented on glass slides and in a magnetic field respectively. The or… more
Date: January 1, 1979
Creator: Vermeglio, A.; Breton, J.; Barouch, Y. & Clayton, R.K.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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DO copper ions influence the reduction of ferricytochrome C by O/sub 2//sup -/. Progress report, December 1, 1977--November 30, 1978

Description: Recently, it was suggested that the measured rate of reduction of ferricytochrome C (CIII) by O/sub 2//sup -/ below pH = 8, was too high in the presence of high concentrations of formate (Koppenol et al. (1976), Biochim. Biophys. Acta, 499, 157-168). The high values were attributed to the presence of impurities of copper, which compete on O/sub 2//sup -/. This assumption is consistent with either a decrease in the reduction yield of CIII in the presence of copper, or with a very fast reaction o… more
Date: January 1, 1978
Creator: Ilan, Y; Ilan, Y A & Czapski, G
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Effects of a radiation-induced. cap alpha. -thalassemia on the production of multiple forms of hemoglobins in fetal mice

Description: Embryonic hemoglobins in ..cap alpha..-thalassemic heterozygotes and normal fetuses were compared to study the effects of the deficient ..cap alpha.. chain on the synthesis of hemoglobins in the nucleated embryonic erythrocytes derived from the fetal yolk sac. Acrylamide gel electrophoresis showed that less hemoglobin Ell (..cap alpha../sub 2/y/sub 2/) was formed in ..cap alpha..-thalassemic heterozygotes between 12/sup 1///sub 2/ and 14/sup 1///sub 2/ days of gestation. Quantitation of in vitr… more
Date: January 1, 1978
Creator: Popp, R. A.; Bradshaw, B. S. & Hirsch, G. P.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Organization of the R chromosome region in maize. Progress report, September 1, 1976--October 31, 1977

Description: The position of the controlling element Dissociation, Ds, was mapped in maize in three instances in which it transposed to R, inhibiting expression of the seed-pigmenting determiner, Sc. Mapping was carried out in heterozygotes between the inhibited alleles and a stable allele conditioning only plant pigmentation (P determiner).
Date: July 1, 1977
Creator: Kermicle, J. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Some recent aspects of relaxation line shapes in Moessbauer spectroscopy. [White noise approximation]

Description: Theoretical development in the line shape calculation of Mossbauer resonance spectra involving spin relaxation effects is introduced. The ''eigenvalue'' procedure of calculating line shapes saves computational times by two orders of magnitude compared to traditional methods. This was illustrated by calculating the relaxation spectra of hemoglobin cyanide and a GAMMA/sub 8/ quartet electronic state. The ''white noise approximation'' involved in all the relaxation theory is discussed, and its lim… more
Date: January 1, 1977
Creator: Shenoy, G. K. & Dunlap, B. D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Mitochondrial phenotypes and genotypes in yeast. Technical annual progress report, September 1, 1975--August 31, 1976

Description: An eight component yeast complex III preparation has been obtained which contains up to 6.2 nanomoles of heme b per mg protein. Studies in which the enzyme activity associated with the complex (reduced CoQ-cytochrome c reductase) was monitored, and in which in vivo /sup 14/C-leucine incorporation into whole washed mitochondrial membranes was carried out suggest that (1) entrance of mitochondrially translated proteins into the mitochondrial inner membrane is not dependent upon a prior build up o… more
Date: January 1, 1976
Creator: Rouslin, W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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