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The Gayly Oklahoman (Oklahoma City, Okla.), Vol. 18, No. 2, Ed. 1 Saturday, January 15, 2000 (open access)

The Gayly Oklahoman (Oklahoma City, Okla.), Vol. 18, No. 2, Ed. 1 Saturday, January 15, 2000

Semi-monthly newspaper from Oklahoma City, Oklahoma that includes local, state, and national news and advertising of interest to the Lesbian, Gay, Bisexual, and Transgender (LGBT) community.
Date: January 15, 2000
Creator: Hawkins, Don
Object Type: Newspaper
System: The UNT Digital Library
K-shell ionization and double-ionization of Au atoms with 1.33 MeV photons (open access)

K-shell ionization and double-ionization of Au atoms with 1.33 MeV photons

At relativistic energies, the cross section for the atomic photoelectric effect drops off as does the cross section for liberating any bound electron through Compton scattering. However, when the photon energy exceeds twice the rest mass of the electron, ionization may proceed via electron-positron pair creation. We used 1.33 MeV photons impinging on Au thin foils to study double K-shell ionization and vacuum-assisted photoionization. The preliminary results yield a ratio of vacuum-assisted photoionization and pair creation of 2x10{sup -3}, a value that is substantially higher than the ratio of photo double ionization to single photoionization that is found to be 0.5-1x10{sup -4}. Because of the difficulties and large error bars associated with the small cross sections additional measurements are needed to minimize systematic errors.
Date: January 15, 2000
Creator: Belkacem, A.; Dauvergne, D.; Feinberg, B.; Ionescu, D.; Maddi, J. & Sorensen, A.H.
Object Type: Article
System: The UNT Digital Library
Pawhuska Journal-Capital (Pawhuska, Okla.), Vol. 90, No. 5, Ed. 1 Saturday, January 15, 2000 (open access)

Pawhuska Journal-Capital (Pawhuska, Okla.), Vol. 90, No. 5, Ed. 1 Saturday, January 15, 2000

Semiweekly newspaper from Pawhuska, Oklahoma that includes local, state, and national news along with advertising.
Date: January 15, 2000
Creator: Gann, Sherry
Object Type: Newspaper
System: The Gateway to Oklahoma History
Repair of DNA damaged by ionizing radiation and other oxidative agents in yeast and human (open access)

Repair of DNA damaged by ionizing radiation and other oxidative agents in yeast and human

OAK B202 Treatment of cells with oxidative DNA damaging agents such as ionizing radiation and hydrogen peroxide produces .OH radicals which attack DNA, producing single strand breaks and double strand breaks that have a 3'-blocked terminus with a phosphoglycolate or a phosphate group attached to the 3'-terminus. While DNA strand breaks with 3'-blocked termini are the hallmark of oxidative DNA damage, the mechanisms by which such blocked 3'-termini are removed in eukaryotes remain poorly understood. The goals of this project were to identify the various genes that function in cleaning the blocked 3'ends from DNA strand breaks generated by treatments with ionizing radiation and hydrogen peroxide, to purify the proteins encoded by these genes and to characterize their biochemical activities, and to determine the biological consequences when such damage is not repaired. Because of the high degree of conservation of DNA repair proteins between yeast and humans, and because of the ease of genetic manipulations, initial studies were to be carried out in Saccharomyces cerevisiae. The homologous genes and proteins would then be studied in humans. One aspect of our proposed research was to purify the Apn2 protein from yeast cells and to examine its AP endonuclease and 3'-phosphodiesterase activities. …
Date: January 15, 2000
Creator: Prakash, Louisek
Object Type: Report
System: The UNT Digital Library
Repair of DNA damaged by ionizing radiation and other oxidative agents in yeast and human (open access)

Repair of DNA damaged by ionizing radiation and other oxidative agents in yeast and human

Treatment of cells with oxidative DNA damaging agents such as ionizing radiation and hydrogen peroxide produces .OH radicals which attack DNA, producing single strand breaks and double strand breaks that have a 3'-blocked terminus with a phosphoglycolate or a phosphate group attached to the 3'-terminus. While DNA strand breaks with 3'-blocked termini are the hallmark of oxidative DNA damage, the mechanisms by which such blocked 3'-termini are removed in eukaryotes remain poorly understood. The goals of this project were to identify the various genes that function in cleaning the blocked 3'-ends from DNA strand breaks generated by treatments with ionizing radiation and hydrogen peroxide, to purify the proteins encoded by these genes and to characterize their biochemical activities, and to determine the biological consequences when such damage is not repaired. Because of the high degree of conservation of DNA repair proteins between yeast and humans, and because of the ease of genetic manipulations, initial studies were to be carried out in Saccharomyces cerevisiae. The homologous genes and proteins would then be studied in humans. One aspect of our proposed research was to purify the Apn2 protein from yeast cells and to examine its AP endonuclease and 3'-phosphodiesterase activities. Apn2-like proteins …
Date: January 15, 2000
Creator: Prakash, Louise
Object Type: Report
System: The UNT Digital Library