摘要:

Levamisole [(S)-(-)-2,3,5,6-tetrahydro-6-phenyl-imidazo-(2,1-b) thiazole], an immunomodulating drug and veterinary antihelminthic, is converted by tissues to a sulfhydryl derivative. The drug and its metabolite have mediating effects on lipid peroxidation in microsomal preparations. Because levamisole, as an inhibitor of lipid peroxidation, is a radioprotectant drug, it was of interest to study the response of the drug itself to ionizing radiation. Experiments were directed toward an examination of the effects of gamma radiation on aqueous solutions of levamisole. Chromatographic analysis (TLC) revealed two distinct groups of radiation products. Further separation and analysis of these groups by gas chroma- tography-mass spectrometry (GC-MS) demonstrated that each group of radiation products consists of several components, indicating that the gamma irradiation of non-deaerated solutions of levamisole gives rise to varying amounts of a multiproduct mixture, no constituent of which corresponds to the natural metabolite. Dose effect curves for the levamisole irradiation indicate that the drug is markedly resistant to molecular alteration under the experimental radiation conditions.

ISSN:0033-7579    

DOI:10.1080/00337578008210020

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

A detailed comparison is made of the Kumakhov radiation with the coherent bremsstrahlung, the transition radiation and the synchroton radiation. The coherent bremsstrahlung was shown to be suppressed under channeling conditions. It was found that the mechanism of the appearance of the Kumakhov radiation differs greatly from that for the coherent bremsstrahlung and the transition radiation. The Kumakhov radiation was shown to be more intensive than the synchrotron radiation, especially in the region of high-energy quanta.

ISSN:0033-7579    

DOI:10.1080/00337578008210021

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Radiation initiated in-source polymerisation of trioxane has been studied in super dry state. The dose rate exponent observed is 0.51 indicating the termination to be bimolecular i.e. neutralisation of cation with an anion or an electron. From the molecular weight data the rate constantsktr/kpandkt/k2phave been evaluated to be 2.5 × 10−4and 13 respectively. Thektris the rate constant for the chain transfer to the monomer andkpandktare the rate constants for propagation and termination all expressed in M−1s−1. Assuming the neutralisation between the ions andktvalue of isobutyl vinylether taken from the literature, thekpvalue was calculated to be 1.6 × 105. TheG(total ions)was calculated to be equal to 9.1.

ISSN:0033-7579    

DOI:10.1080/00337578008210022

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The effects of irradiation pulsing on the enhanced climb-glide creep strain are analyzed. A variety of pulsed systems have been studied by adytically modeling the time-dependence of the bulk point-defect concentrations given by the rate theory. Equations for the creep strain are derived for Tokamak-type fusion reactors, pulsed accelerators and inertial confinement fusion reactors, including the effects of mutual point-defect recombination. The creep in pulsed fusion reactors is compared with the creep in systems subject to steady irradiation of equal total dose. It is found that point-defect concentration cycling (due to radiation pulsing) results in enhancement of the irradiation creep strain. In particular, a very large temperature-dependent enhancement is found for inertial confinement fusion reactors. The theoretical results are also compared with experimental data on deuteron irradiated nickel. Good agreement is obtained with the parameters used.

ISSN:0033-7579    

DOI:10.1080/00337578008210023

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor