ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTArgon-sensitized radiolysis of methane and ethane in the liquid phaseNorman V. KlassenCite this: J. Phys. Chem. 1968, 72, 3, 1076–1078Publication Date (Print):March 1, 1968Publication History Published online1 May 2002Published inissue 1 March 1968https://pubs.acs.org/doi/10.1021/j100849a054https://doi.org/10.1021/j100849a054research-articleACS PublicationsRequest reuse permissionsArticle Views17Altmetric-Citations3LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access options Get e-Alerts
SummaryThe reactions of eaq−, OH and H with oxytocin and lysine vasopressin have been investigated by pulse radiolysis. Reactivity is largely confined to the tyrosine, phenylalanine and cystine residues. The cyclic radical anion produced by reaction with eaq− is considerably more stable than its open-chain counterpart.
The authors of a recent paper (Claridge Mackonis et al 2007 Phys. Med. Biol. 52 5469–82) measured cell survival in spatially modulated radiation fields. They claim to have identified two new types of radiation-induced bystander effect. We conclude that their claims are not supported by their data.
In experiments on the pulse radiolysis of crystalline D/sub 2/O ice at a nominal temperature of 6 K, yields of e/sup -//sub v/is, e/sup -//sub i/r and the OD radical have been measured as a function of accumulated dose. The yield of e/sup -//sub i/r shows a large effect of dose, increasing from Gepsilon-c = 1.03 x 10/sup 4/ (Gapprox. =0.27) for a previously unirradiated crystal to Gepsilon-c = 4.1 x 10/sup 4/ (Gapprox. =1.08) for a sample that had received 300 krad. The effect of dose is decreased to about half by annealing at 12.5 K, but can only be completely eliminated by annealing above 100 K. The effect is interpreted as being due to the scavenging, by D and OD, of D/sub 2/O/sup +/ which otherwise recombines with e/sup -//sub q/f. The G of OD at 6 K for a previously unirradiated crystal was measured as 3.8; this is much higher than the previously reported G of OH from ..gamma..-irradiated H/sub 2/O ice at 4 K.
The yields and decay rates of two types of localized excess electrons, absorbing in the visible (e − vis ) and in the infrared (e − ir ), have been compared in four pulse-irradiated H 2 O glasses and their D 2 O analogues, and in irradiated H 2 Oand D 2 O ice crystals, all at 73 K. If it is assumed that extinction coefficients of e − vis and e − ir at 650 nm and 1800 nm, respectively, are independent of isotopic substitution for both glasses and ice, the G's for both types of localized electrons are lower in all the H 2 O solids studied than in the corresponding D 2 O solids. The largest effect of isotopic substitution was found in the lifetime of e − vis in the crystal; at 73 K the inital half-life for decay of e − vis is approximately 14 times longer in D 2 O than in H 2 O ice. Even at 6 K the decay of e − vis in H 2 O ice is very rapid with an initial half-life of about 75 ns.
SummaryPulse-radiolysis studies of aqueous papain solutions have been made over the 50 µs to 0·40 s time-scale and the 300 to 500 nm wave-length range. For the intermediates formed from both e−aq and OH, the observed changes in optical density over the above time-scale are independent of papain concentration and dose per pulse. They are attributed to sequences of reactions within the same papain molecule. The overall conclusions are similar to those reported previously for the decay of ribonuclease intermediates (Lichtin, Ogdan and Stein 1972) and their implications for the interpretation of the mechanism of 60Co inactivation of papain are pointed out.
The initial (?200 nsec) spectra of the trapped electron are similar in C2H5OH, C2H5OD, C2D5OH, and C2D5OD glasses at 76 K with λmax ∼1300 nm. The kinetics of the spectral shifts to the stable values of λmax near 540 nm are similar for C2H5OH and C2H5OD and resemble the kinetics of a series of first order processes or of tunneling reactions. Structure seems to be present in the partially relaxed spectra and may result from specific geoemetrical orientations of first solvation shell molecules.
