Atomic Energy of Canada Limited

About: Atomic Energy of Canada Limited is a company organization based out in Ottawa, Ontario, Canada. It is known for research contribution in the topics: Zirconium alloy & Neutron. The organization has 4845 authors who have published 4826 publications receiving 102951 citations.

Low Doses of Radiation are Protective In Vitro and In Vivo: Evolutionary Origins

Abstract: Research reports using cells from bacteria, yeast, alga, nematodes, fish, plants, insects, amphibians, birds and mammals, including wild deer, rodents or humans show non-linear radio-adaptive processes in response to low doses of low LET radiation. Low doses increased cellular DNA double-strand break repair capacity, reduced the risk of cell death, reduced radiation or chemically-induced chromosomal aberrations and mutations, and reduced spontaneous or radiation-induced malignant transformation in vitro. In animals, a single low, whole body dose of low LET radiation, increased cancer latency and restored a portion of the life that would have been lost due to either spontaneous or radiation-induced cancer in the absence of the low dose. In genetically normal fetal mice, a prior low dose protected against radiation-induced birth defects. In genetically normal adultmale mice, a low dose prior to a high dose protected the offspring of the mice from heritable mutations produced by the large dose. The results show that low doses of low-LET radiation induce protective effects and that these induced responses have been tightly conserved throughout evolution, suggesting that they are basic responses critical to life. The results also argue strongly that the assumption of a linear increase in risk with increasing dose in humans is unlikely to be correct, and that low doses actually reduce risk.

The diffusion of gold in lead single crystals

Abstract: The diffusion of radioactive 198Au and 199Au has been measured in 99·999% pure lead single crystals over the temperature range of 190°c to 320°C. The final distribution of the solute, which was initially evaporated as a thin film on the surface of the lead specimens, could be represented in most cases by c(x, t)=S 0[πDt]−1/2exp—[x 2/4Dt], although departures from this were occasionally noted. The temperature dependence of the diffusion coefficient was found to be D=8·7 × 10−3 exp—[10 000/RT] cm2/sec. A number of models that could account for the unusually rapid diffusion of gold in lead are examined. It is concluded that the present results, and those of others for related phenomena, can be rationalized by assuming that gold enters and diffuses through the lead in two states of solution, substitutional and interstitial.