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.

Angular Distributions from (n, p) Nuclear Reactions

Abstract: It is shown that angular distributions of high-energy proton groups from ($n, p$) reactions should evidence sharp maxima near the forward direction, which arise from neutrons with large impact parameters interacting with protons out in the "tails" of the initial nucleus. The positions of these peaks are characterized by the allowed values of orbital angular momenta ${l}_{n}$ with which the neutron can be captured to form the final state. A study of such distributions therefore may well lead to information concerning spins and parities of nuclear energy levels, as in the case of stripping reactions. For most nuclei, compound nucleus formation should contribute little to such proton groups. For light nuclei, in order that the sharp maxima stand out above the compound nucleus background, it is probably necessary that the incident neutron energy not be near a resonance of the compound nucleus.

Genetic control of radiation sensitivity in Schizosaccharomyces pombe.

Abstract: Genetic analysis of a large number of radiation-sensitive mutants of S. pombe , isolated in different laboratories, showed that these isolates represent 22 non-allelic loci. The mutants were shown to fall into three distinct classes concerning response to UV and ionizing radiation, including two mutants which are primarily sensitive to ionizing radiation but not to UV. Single-gene mutants were crossed to obtain supersensitive double mutants. Such double mutants showed a marked increase in sensitivity to a variety of inactivating agents as compared to the parental strains. The isolation of three classes of radiation-sensitive mutants and the construction of double mutants implies the presence of multiple pathways in S. pombe for repair of radiation-induced damage. The bearing of these data on cellular repair mechanisms in eukaryotes is discussed.

Cancer promotion in a mouse-skin model by a 60-Hz magnetic field: II. Tumor development and immune response

Abstract: This paper describes preliminary findings on the influence of 60-Hz (2-mT) magnetic fields on tumor promotion and co-promotion in the skins of mice. The effect of magnetic fields on natural killer (NK) cell activity in spleen and blood was also examined. Groups of 32 juvenile female mice were exposed to the magnetic field as described in part I. The dorsal skin of all animals was treated with a subthreshold dose of the carcinogen 7,12-dimethyl-benz(a)anthracene (DMBA). One week after the treatment, two groups were sham exposed (group A) or field exposed at 2 mT (group B) 6 h/day for 21 weeks, to test whether the field would act as a tumor promoter. No tumors developed in these two groups of mice. To test whether the magnetic field would modify tumor development by directly affecting tumor growth or by suppressing immune surveillance, two additional groups of mice were treated weekly with the tumor promoter 12-0-tetradecanoylphorbol-13-acetate (TPA) and then either sham exposed (group C) or field exposed (group D). The time to appearance of tumors was shorter (but not statistically so) in the group exposed to magnetic fields and TPA. Some differences in NK cell activity and spleen size were observed between the sham- and field-exposed groups.