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Removal of uv-induced pyrimidine dimers from the replicated and unreplicated DNA of human fibroblasts

Description: Excision repair in uv irradiated human fibroblasts has been examined in portions of DNA replicating after irradiation versus those remaining unreplicated. Two approaches, one using a uv-endonuclease to estimate pyrimidine dimers remaining in DNA, the other using density labeling to measure excision resynthesis, indicate that the extent of repair is the same for both replicated and unreplicated DNA.
Date: January 1, 1978
Creator: Waters, R.
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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Organic Photochemical Storage of Solar Energy. Progress Report, July 1, 1977--Feburary 28, 1978

Description: The prospects for driving endoergic reactions of simple, relatively abundant organic chemicals by photochemical means have been examined. Strategies for utilization of light of varying wavelength involve sensitization mechanisms which depend on the redox properties of energy storing substrates and photosensitizers. Of principal interest is valence isomerization which can be induced by electron donor-acceptor interaction between substrate and sensitizer in an excited complex or exciplex. Photoph… more
Date: March 1, 1978
Creator: Jones, G., II
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Experimental investigation of the chemistry of exccited states of rare gases. Fourth quarterly (and annual) progress report, July 15, 1978-October 15, 1978. [Reaction of Ar(/sup 3/P/sub 2/) or Xe(/sup 3/P/sub 2/) with XeO/sub 4/]

Description: A brief account is given of work on the quenching of XeF(B) and other excited rare-gas systems. A more detailed report is given of the studies of the vacuum uv photolysis of XeO/sub 4/ and reactions of Xe(/sup 3/P/sub 2/) and Ar(/sup 3/P/sub 2/) with XeO/sub 4/. (DLC)
Date: December 1978
Creator: Setser, D. W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Laser enhanced chemical reaction studies. Progress report, 1 July 1978--31 March 1979

Description: It was found that COF/sub 2/ multiphoton dissociates when pumped by a focused TEA CO/sub 2/ laser operating on the P(22) line of the 10.6..mu.. branch with an energy of approx. 500 mJ/pulse. F atoms were produced by the laser and their velocity was essentially thermal (300/sup 0/K). Parent fluorescence from highly excited COF/sup 2/ appeared near 2.5 ..mu... Serious errors can occur in the measurement of the rate of reaction of atomic fluorine with hydrogen at very low hydrogen pressure.
Date: January 1, 1978
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Balance of the tropospheric ozone and its relation to stratospheric intrusions indicated by cosmogenic radionuclides. Technical progress report, 1 November 1977--30 June 1978. [/sup 7/Be, /sup 32/P, /sup 33/P]

Description: The study of the balance of the tropospheric ozone as a function of atmospheric pollutants and tropospheric transport has been started. Continuous recordings are available of ozone concentration at three levels (3000 m, 1800 m, and 700 m a.s.l.) and of the concentration of the cosmogenic radionuclides /sup 7/Be, /sup 32/P, /sup 33/P, and the CO/sub 2/-concentration. Ozone concentrations >70 ppB have been observed after stratospheric intrusions as well as in consequence of photochemical react… more
Date: January 1, 1978
Creator: Reiter, R; Kanter, H J; Sladkovic, R; Jaeger, H & Mueller, H
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Studies in chemical dynamics

Description: Progress made in the following studies is reported: low-energy electron scattering; variable-angle photoelectron spectroscopy; laser photochemistry and spectroscopy; and collisions in crossed molecular beams.
Date: November 22, 1978
Creator: Kuppermann, A
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Formation and Transformation of Polycyclic Organic Matter From Coal Combustion. [Adsorption of Pah on Fly Ash; Photo Decomposition]

Description: Research was carried out on vapor-to-particle condensation (adsorption of PAH on fly ash) and photochemical transformation of particulate POM. Results on the first research topic show that POM vapor is adsorbed onto co-entrained particles as the temperature falls. Photodecomposition of PAH's is decreased substantially by adsorption onto coal fly ash particles, although certain PAH's undergo rapid oxidation in the dark when adsorbed onto fly ash. Implications of the results for assessing the env… more
Date: January 1, 1978
Creator: Natusch, D.F.S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Tunable lasers for waste management photochemistry applications. [Dye lasers, excimer lasers, IR lasers]

Description: A review of lasers with potential photochemical applications in waste management indicates that dye lasers, as a class, can provide tunable laser output through the visible and near-uv regions of the spectrum of most interest to photochemistry. Many variables can affect the performance of a specific dye laser, and the interactions of these variables, at the current state of the art, are complex. The recent literature on dye-laser characteristics has been reviewed and summarized, with emphasis o… more
Date: September 1, 1978
Creator: Finch, F.T. (comp.)
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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uv photobiology: DNA damage and repair

Description: The following topics are discussed: targets that determine the fate of the cell when uv light interacts with a cell; comparison of action spectrum for a given biological effect with the absorption spectrum of different biological macromolecules; biological effects of damage to DNA; measurement of mutations; chemical damage to DNA; photoreactivation; role of pyrimidine dimers in induction of skin cancer by uv. (HLW)
Date: January 1, 1978
Creator: Sutherland, B. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Thermal and Photochemical Decomposition of Particulate Pah. [Adsorbed on Coal Fly Ash]

Description: Photochemical decomposition of several polycyclic aromatic hydrocarbons (including benzo(a)pyrene) proceeds much more slowly when the compounds are adsorbed on coal fly ash than in solution or when adsorbed on other solid surfaces. Certain other polycyclic hydrocarbons (fluorene, the benzofluorenes, 9, 10-dimethylanthracene, and 9, 10-dihydroanthracene) undergo rapid, non-photochemical, degradation when adsorbed onto fly ash surfaces; the extent of this decomposition depends upon the nature of … more
Date: January 1, 1978
Creator: Korfmacher, W. A.; Natusch, D. F.S.; Taylor, D. R.; Wehry, E. L. & Mamantov, G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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uv photobiology: postreplication repair. [Escherichia coli, synchrotron radiation]

Description: The following topics are discussed: insertion of incorrect bases in DNA; ability of DNA polymerase to copy uv-irradiated DNA; role of enzymes in repair of DNA; effects of uv radiation on molecular weight of DNA; photoreactivation; repair of DNA in Escherichia coli and xp cells following uv radiation; and synchrotron radiation studies on DNA repair. (HLW)
Date: January 1, 1978
Creator: Sutherland, B. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Radiation Laboratory quarterly report, January 1, 1977--March 31, 1977

Description: Some of the studies in progress are: distribution of deposited energy around heavy-ion tracks; effect of trapping on the thermalization of electrons in hydrocarbon liquids; effect of field-dependent mobility on escape probability; kinetics of electron scavenging reactions; second-order optical properties of solvated electrons; model molecular orbital studies of the chemisorption of atomic hydrogen and oxygen on aluminum surfaces; calculation of sum rule moments for H/sub 2/O; early events in pu… more
Date: August 12, 1978
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Laser photochemical reaction dynamics in formaldehyde

Description: Appearance rate constants of molecular photochemical products were measured following laser photolysis of formaldehyde in the near ultraviolet. The pressure dependence of appearance rates was studied for three formaldehyde isotopic species: H/sub 2/CO, HDCO, and D/sub 2/CO. The effect of added foreign gases on those rates in H/sub 2/CO has been determined for He, Ar, Xe, and NO. The energy dependence of photodissociation rates has been examined following laser photolysis at 354.7 and 299.1 nm a… more
Date: August 1, 1978
Creator: Zughul, M.B.A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

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
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Photochemistry and photobiology of DNA containing 5-iodouracil and 5-iodocytosine. [Escherichia coli, Bacillus subtilis]

Description: The quantum yields for the photolysis of iodinated derivatives of cytosine (leading to the loss of iodine) has been measured for 313 nm radiation and found to decrease from 0.024 for IodCMP down to 0.007 for both Poly(C) and DNA containing 5-IodCyt. In DNA, approximately 1 clean chain break and 1 alkali-labile bond were formed for every 10 iodines lost. Incorporation of iodinated cytosine or uracil into the DNA of Escherichia coli or Bacillus subtilis was shown to have a large effect on the bio… more
Date: January 1, 1978
Creator: Rahn, R.O.; Stafford, R.S. & Hadden, C.T.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Infrared laser induced chemical reactions: calculations for X + H/sub 2/. -->. HX + H

Description: The collision dynamics in collision induced chemical reactions were studied. It was found that reactive systems exhibit a collision induced absorption which enhances the rate of reaction by effectively lowering the activation energy. A classical model was developed that describes the phenomenon correctly which can be used to investigate its various aspects theoretically.
Date: September 1, 1978
Creator: Orel, A. E. & Miller, W. H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Construction of surrogate CHEmical MEchanisms (SCHEMEs) for atmospheric photochemical systems

Description: During the past several years it has become apparent that homogeneous gas-phase reactions of pollutants in the troposphere, i.e., the formation of photochemical smog and the oxidation of SO/sub 2/, occur to a great extent by elementary reactions involving chain carrying free-radicals (HO, HO/sub 2/, RO, RO/sub 2/, RCOO/sub 2/) whose concentrations are governed by the concentrations of trace molecular constituents including NO, NO/sub 2/, CO, O/sub 3/, and organics, as well as sunlight. For the … more
Date: January 1, 1978
Creator: Levine, S. Z. & Schwartz, S. E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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