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This work reports an electron spin resonance study of the reactions of cysteine, glutathione and penicillamine thiyl radicals with molecular oxygen in frozen aqueous solutions at low temperatures. For all three thiols, the thiyl radical, RS., is found to react with oxygen to form the thiol peroxyl radical, RSOO(.). On the absorption of visible light,(More)
This study investigates the extent of hole delocalization in one-electron oxidized adenine (A) and guanine (G) stacks and shows that new IR vibrational bands are predicted that are characteristic of hole delocalization within A-stacks. The geometries of A-stacks (A(i); i = 2-8) and G-stacks (GG and GGG) in their neutral and one-electron oxidized states were(More)
Using Electron Spin Resonance spectroscopy at low temperatures, we find that thiyl radicals resulting from irradiation of frozen aqueous solutions of a variety of thiols, including cysteine, glutathione, and penicillamine react with oxygen to form sulfinyl (RSO.) radicals. The identity of the cysteine sulfinyl radical has been confirmed by the use of(More)
Migrating resources is a useful tool for balancing load in a distributed system, but it is difficult to determine when to move resources, where to move resources, and how much of them to move. We look at resource migration for file system metadata and show how CephFS's dynamic subtree partitioning approach can exploit varying degrees of locality and balance(More)
Low-energy electrons (LEEs) are increasingly recognized as a significant contributor to DNA damage and resultant cellular radiation damage.1 LEEs below 15 eV are produced copiously (4 × 104 per MeV energy deposited) along the tracks of the energy deposited.1a It is well-established that LEEs lead to induce a variety of damages within DNA such as singleand(More)
The reactions of sulphonyl peroxyl radicals with DNA and its components at low temperatures are investigated through use of electron spin resonance spectroscopy. Radiolysis of cysteine sulphinic acid solution in oxygenated aqueous 5 mol dm-3 LiCl glass has been employed to generate sulphonyl peroxyl radicals, CysSO2OO.. The mechanism of production is a(More)
n-Propyl gallate (nPG) is a food preservative that is generally regarded as safe by the US FDA. It suppresses oxidation in biological systems. The mechanism by which nPG acts in biological systems is uncertain. We investigated whether nPG protected cultured lens epithelial cells from H(2)O(2)-induced damage. Cells were treated with H(2)O(2) or with nPG and(More)
The release of unaltered bases from irradiated DNA, hydrated between 2.5 and 32.7 mol of water per mole of nucleotide (gamma), was investigated using HPLC. The objective of this study was to elucidate the yield of the four DNA bases as a function of dose, extent of hydration, and the presence or absence of oxygen. The increase in the yield of(More)
The induction of base damage products in gamma-irradiated DNA, hydrated between 2.5 and 32.8 moles of water per mole of nucleotide (tau), was investigated using the gas chromatography/mass spectrometry-selected ion monitoring technique. In general, the yields of the measured base damage products were found to be dependent on the extent of the hydration when(More)
PURPOSE To investigate the ability of the nitroxide free radical and superoxide dismutase mimic 4-hydroxy-2,2,6,6-tetramethylpiperidine-n-oxyl (TEMPOL) to protect against x-ray-induced lens DNA damage and cataract formation in the rabbit. METHODS Eleven gray (Gy) x-rays was delivered twice, with a 48-hour interval, to the same eye of 5-week-old rabbits.(More)