共查询到20条相似文献,搜索用时 15 毫秒
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Possible late effects of sublethal levels of whole-body gamma irradiation on growth of burro foals were studied. Two trials included 31 nonirradiated foals and 32 foals that were exposed to 250 R of 60Co gamma radiation during their fourth month of life. The foals were weaned 90 days postirradiation and allotted into treatment groups based on radiation treatment, weight, sex, and size. Each group was then randomly selected to be fed a ration containing either 9 %, 14 %, or 18 % crude protein in the first trial and either 9 % or 18 % in the second trial. The length of these trials was 364 days. Criteria used to evaluate the treatments included feed consumption, body weight gains, feed efficiency, increase in height, and increase in heart girth. Least-squares analysis of these data indicated that radiation had no significant effect on any of the traits tested. There was a consistent though nonsignificant trend for irradiated foals to be less efficient in feed utilization than their nonirradiated counterparts. 相似文献
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Installation of the first United States 201-source 60Co gamma unit for stereotactic radiosurgery was completed at the University of Pittsburgh in May, 1987. Despite a very favorable 19-year experience in Stockholm, introduction of this technology into the US proved to be a formidable task. Extensive internal and government regulatory review by the Health Systems Agency, the Food and Drug Administration and the Nuclear Regulatory Commission ultimately resulted in approval of marketing and use of the gamma unit. Clinical use and radiobiological research has begun. 相似文献
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Michael A. Sweeney Anthony P. Toste Cyril Ponnamperuma 《Origins of life and evolution of the biosphere》1976,7(3):187-189
Aqueous solutions of hydrogen cyanide (0.004–0.1M) were exposed to cobalt-60 gamma rays. Among the products formed on hydrolysis of the irradiated solution; glycine, alanine, valine, serine, threonine, aspartic acid, and glutamic acid have been identified.Portions of this work were performed at the NASA-Ames Research Center, Moffett Field, California, 94035. 相似文献
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Escherichia coli transiently increases both the [ATP]/[ADP] ratio and the negative supercoiling of plasmid DNA when it is shifted to high osmolarity. Here we report that a mutant lacking all saturable K+ transport systems increases the negative supercoiling of the plasmid DNA under upshock but cannot further relax DNA. The mutant dnaK756 behaves like the K+ transport mutant. 相似文献
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D. C. Lloyd A. A. Edwards J. S. Prosser M. J. Corp 《Radiation and environmental biophysics》1984,23(3):179-189
Summary The induction of unstable chromosome aberrations in human peripheral blood lymphocytes exposed in vitro to protracted doses of cobalt-60 radiation is presented. Four dose response curves have been produced using constant exposure times of 1, 3, 6, and 12 h. The data fit well to the linear quadratic model and the yield coefficients have been compared with those obtained for acute (< 10 min) exposure. The quadratic coefficient is dependent on irradiation time and decreases approximately as predicted by Lea and Catcheside'sG-function hypothesis. The possibility of a small proportion of much longer lived breaks is discussed. For purposes of biological dosimetry it is sufficient to assume a mean time of 2 h and a single exponential function for the repair of lesions when relating the effects of brief and protracted exposure. 相似文献
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A study was made to observe the effect of cobalt-60 irradiation on the viability of Paragonimus westermani metacercariae in Sinopotamon chekiangense crabs. The crabs were collected in mountain regions of the Zhejiang Province of China in which paragonimiasis is endemic. Adult cats and albino mice were infected with metacercariae irradiated at different doses. Dissection of the host animals was conducted 90 or 30 days, respectively, after infection for recovery of lung flukes. Anti-metacercariae antibody in infected mice was measured by enzyme-linked immunosorbent assay (ELISA). Results showed that metacercariae were unable to grow into adult worms in cats after exposure to gamma irradiation at a dose of 0.10 kGray. However, a small number of metacercariae exposed to a dose of 2.0 kGray excysted and survived in 1 mouse for 30 days. No worm was recovered from mice when the metacercariae were irradiated at a dose of 2.5 kGray. Seropositive results by ELISA were obtained when the mice were infected with metacercariae irradiated at doses ranging from 2.0 to 3.5 kGray. 相似文献
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D M Lilley 《Biochemical Society transactions》1986,14(2):211-213
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《Cell cycle (Georgetown, Tex.)》2013,12(9):1339-1340
Comment on: Witz G, et al. Proc Natl Acad Sci USA 2011; 108:3608-11. 相似文献