[en] Elk spend the winter in areas at Los Alamos National Laboratory (LANL) that may contain radioactivity above natural and/or worldwide fallout levels. This study was initiated to determine the levels of ⁹⁰Sr, ¹³⁷Cs, ²³⁸Pu, ²³⁹Pu, and total uranium in various tissues (brain, hair, heart, jawbone, kidneys, leg bone, liver, and muscle) of adult cow elk that use LANL lands during the fall/winter months. No significant differences in radionuclide contents were detected in any of the tissue samples collected from elk on LANL lands as compared with elk collected from off-site locations. The total effective (radiation) dose equivalent a person would receive from consuming 3.2 lb of heart, 5.6 lb of liver, and 226 lb of muscle from elk that winter on LANL lands, after natural background has been subtracted, was 0.00008, 0.0001, and 0.008 mrem/yr, respectively. The highest dose was less than 0.01% of the International Commission of Radiological Protection permissible dose limit for protecting the public

[en] Elk spend the winter in areas at Los Alamos National Laboratory (LANL) that may contain radioactivity above natural and/or worldwide fallout levels. This study was initiated to determine the levels of ⁹⁰Sr, ¹³⁷Cs, ²³⁸Pu, ²³⁹Pu, and total uranium in various tissues (brain, hair, heart, jawbone, kidneys, leg bone, liver, and muscle) of adult cow elk that use LANL lands during the fall/winter months. No significant differences in radionuclide contents were detected in any of the tissue samples collected from elk on LANL lands as compared with elk collected from off-site locations. The total effective (radiation) dose equivalent a person would receive from consuming 3.2 lb of heart, 5.6 lb of liver, and 226 lb of muscle from elk that winter on LANL lands, after natural background has been subtracted, was 0.00008, 0.0001, and 0.008 mrem/yr, respectively. The highest dose was less than 0.01% of the International Commission on Radiological Protection permissible dose limit for protecting the public

[en] Products of radiolysis of penicillamine in 1 M HClO₄ are reported and their yields discussed. The reactions of .OH and .CH₂OH are qualitatively similar to those observed for cysteine and produce primarily RS. radicals. However, the secondary reactions of RS. radicals give rise to a substantially higher yield of trisulfide (RSSSR) than is observed with cysteine. This appears to be due to the presence of weaker C--S bonds in the tertiary C--SH compound and to the fact that this bond can be broken as a result of interactions between RS. and RSH, possibly via the formation of a RSS(H)R intermediate. The magnitude of the rate constant ratio k₃(k₄ + k₆)^-1 at 1 +- 1⁰C is 0.54 +- 0.10. At 23⁰C it was found to be 0.50 +- 0.10 in good agreement with an earlier value of 0.44

[en] Here the authors focus on chemical reactions and products from irradiated gases. A typical scheme of physical and chemical processes in a system where electrons do not react with the neutral molecules is shown. The reader may note that the final products T, E, Z, and F arise from the parent molecule G through several different types of reactions, which involve electrons, excited molecules (G*) and ions (G ^+*), free radicals (· Q and · R), and stable ground state ions M⁺ · 2G, before they are neutralized. The time scales of the various processes at 1 atmosphere (atm) are shown in column three. Also given is the form of their dependence (if any) on dose rate I and concentration of G or other species. The time scales also depend on the chemical structure of G

[en] Glutathione reacts with papainCys₂₅SOH, formed by the reaction of papain with hydrogen peroxide, to give papainCys₂₅SSG. Subsequent reaction of this mixed disulfide with glutathione is slow (k < 3 M^-1 sec^-1). However, at 30⁰C it is readily cleaved by cysteine to form active papain, i.e., papainCys₂₅SH. Glutathione resembles cysteine in protecting papain by the scavenging of .OH radicals, but, unlike cysteine, glutathione gave no evidence for the repair of enzyme radical lesions or for the conversion of papainCys₂₅S. radicals to repairable derivatives. Its overall effectiveness for reducing the radiation inactivation of papain in aqueous solution is much less than that of cysteine

No abstract available

[en] The rate constant for reaction of Br₂ radicals with dithiodipropionic acid (approx. 4.2 x 10⁸ mol^-1dm³s^-1) was independent of pH in the range 6.6-11.0 and was approx. 4.5 times smaller than those for the neutral dimethyl and diethyl disulfides Br₂^- only reacted with the disulfides of cysteamine, cysteine, and penicillamine with an appreciable rate (> 10⁸mol^-1dm³s^-1) when one or both of the amino groups were unprotonated. Homocystine was less sensitive to the degree of protonation. While the reaction of Br₂ radicals with dithiodipropionic acid yielded a transient (lambda/sub max/ approx. = 450 nm) which possessed the characteristics of a disulfide cation, the amino-containing disulfides cited above produced transients which adsorbed with a lambda/sub max/ near 380 nm. The latter transients decayed by second-order kinetics over the pH range studied, and they gave no evidence of reaction with OH^-. These species have been tentatively identified as perthiyl (RSS.) radicals. Hydroxyl radicals produced composite spectra consisting of the 380-nm species and other transients which absorbed below 350 nm. Oxidized glutathione gave only weak absorptions on reaction with Br₂ and OH radicals. The yields of sulfydryl molecules have been measured for cystine and dithiodipropionic acid. The mechanisms of radiolysis are discussed in the light of present results and earlier studies

[en] Studies of ion neutralization reactions in gases are reviewed with particular reference to the effects of increasing frequency of collisions with neutrals on the overall rate coefficient α. Since the publication of earlier reviews, progress has been made in the following areas. Firstly the pressure dependence of α has been examined in several systems over a very wide range. It is shown that this dependence can be treated reasonably well by the equations for diffusion controlled reactions in fluids. Secondly, interesting developments have occurred in our understanding of the effects of molecular structure and clustering of the ions in two body ion-ion and ion-electron neutralization reactions. Also progress has been made in the study of three body mechanisms, particularly for ion-electron reactions, the rates of which have now been investigated at much higher pressures than previously. Finally the experiments are compared to recently derived theory, and methods of incorporating the two and three body stabilization coefficients into the overall equation for α are examined. (author)

[en] Published in summary form only

[en] The gas phase Co⁶⁰ radiolysis of mixtures of HBr and H₂S has been studied at room temperature. In agreement with earlier studies HBr enhanced the hydrogen yield from H₂S by reacting with thermal electrons. However, using SF₆ as a competitive electron scavenger it was shown that (HBr)₂ dimers are not the only species reacting with electrons to form hydrogen. The excess capture rate was first order in both [HBr] and [H₂S]. Reaction mechanisms are proposed. From this and earlier studies the reactions of (H₂S)₂ species appear to be relatively slow. (author)