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  • Author or Editor: H. Arnikar x
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Abstract  

The diffusion of Rose Bengal131I in agar gel is studied in the concentration range of 10–7 to 10–5M. In addition, effects due to varying the concentration of the gel and temperature are reported.

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Abstract  

Tracer and self-diffusion coefficients for Rosebengal labelled with131I are determined in agar gel medium at different temperatures and the activation energies for the two processes are determined by zone diffusion technique. The slight difference in tracer and self-diffusion values observed is small enough to be consistent with Hertz's recent theory of linear response of tracer diffusion coefficients in electrolyte and non-electrolyte systems.

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Abstract  

Volume diffusion coefficients of I anions in the near surface region of silver have been determined using131I. The distribution of the labelled ions with depth is determined by acid etching and counting the residual activity. The coefficient of diffusion is determined for surface layers of three different thicknesses over the temperature range 373–823 K. The mechanism proposed assumes the dissociation of Ag+I in surface layer and the diffusion of I into the interstitial free space immediately beneath the surface. This process is found to be accompanied by a small negative entropy change.

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Abstract  

Tracer studies using65Zn and58Co showed that of the four forms ofMethanosarcina hydrogenases, the A form has about 15% of acid labile zinc, while the hydrogenase D has about 50% of cobalt of the total bound activity in the cell and the other two forms B and C have neither zinc nor cobalt. However, all hydrogenases are known to contain iron, sulfur and probably nickel in trace amounts. All air-oxidized forms of hydrogenases catalyze the reduction of methyl viologen after a finite incubation period. The reduction is revealed by an increase in the absorption peak at 602 nm. On -irradiation, all the four hydrogenases changed to more stable oxidized forms, as indicated by an increase in the optical absorption in the visible region at 405 nm. The irradiated samples showed a greater time lag before they could reduce methyl viologen, the time lag increasing with the -dose. The irradiated enzymes could be reactivated by flushing with H2. The zinc-bearing hydrogenase A alone appeared to be immune to -radiation in its ability to reduce methyl viologen. This may be due to the zinc having no unpaired electrons to interact with -radiation or the primary radiolytic products.

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Abstract  

A spectrophotometric study is reported of the pigment formation from free radicals produced from o-dianisidine dihydrochloride and pyrogallol by the action of -irradiated sodium chloride. The species liberated during dissolution of the -irradiated salt also greatly enhance the rate of catalytic formation of the pigment due to peroxidase enzyme in the presence of hydrogen peroxide. The G values for these systems are compared.

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Abstract  

A spectrophotometric study is reported of the oxido-reductant reactions with the major coenzymes as NADH, NADPH, NAD+, NADP+ and FAD effected by low dose and by the energy stored in F and hole centres in -irradiated sodium chloride. The G values for the two modes of these redox reactions are compared.

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Abstract  

A spectrophotometric study is reported of the reduction of some dyes having the methylene blue structure used in bacteriological staining. The reduction is effected by the species liberated during the dissolution of -irradiated sodium chloride, in the same way as by direct low -dose. The G values for the two modes of the reduction are compared and the effects of radical scavengers on the reactions are studied. Results are found to be similar to the chemically and biologically induced reductions. The dyes studied include besides Methylene Blue, Janus Green B and Nile Blue sulfate.

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Abstract  

The products of

\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$G_{NH_4 CNS}$$ \end{document}
was 0.083 molecules of NH4CNS for 100 eV absorbed. A suitable mechanism for the process of isomerization is suggested involving the hydrated electrone aq, the major primary product of water radiolysis. The mechanism is consistent with the observed effect of the addition of acetone, a well-known electron scavenger. This suppressed the yield NH4CNS by about 25%.

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