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: Neutron & Zirconium alloy. The organization has 4845 authors who have published 4826 publications receiving 102951 citations.

Azimuthal distributions in heavy ion collisions and the nuclear equation of state

Abstract: For near central collisions of Nb on Nb at a laboratory energy of 650 MeV per projectile nucleon we calculate inclusive cross sections as a function of the azimuthal angle where this angle is measured from the reaction plane. The azimuthal dependence is strongly influenced by the nuclear equation of state and is a useful quantity to measure.

Low-Dose Radiation Exposure and Atherosclerosis in ApoE−/− Mice

Abstract: The hypothesis that single low-dose exposures (0.025–0.5 Gy) to low-LET radiation given at either high (about 150 mGy/min) or low (1 mGy/min) dose rate would promote aortic atherosclerosis was tested in female C57BL/6J mice genetically predisposed to this disease (ApoE−/−). Mice were exposed either at an early stage of disease (2 months of age) and examined 3 or 6 months later or at a late stage of disease (8 months of age) and examined 2 or 4 months later. Changes in aortic lesion frequency, size and severity as well as total serum cholesterol levels and the uptake of lesion lipids by lesion-associated macrophages were assessed. Statistically significant changes in each of these measures were observed, depending on dose, dose rate and disease stage. In all cases, the results were distinctly non-linear with dose, with maximum effects tending to occur at 25 or 50 mGy. In general, low doses given at low dose rate during either early- or late-stage disease were protective, slowing the progression of...

New intermediate subviral particles in the in vitro uncoating of reovirus virions by chymotrypsin.

Abstract: Reovirus virions, grown in suspension cultures of L cells and extensively purified by density gradient and velocity gradient centrifugation after their release from cell debris by fluorocarbon extraction, are characterized by a mean particle diameter of 73 nm and a density in CsCl of 136 to 137 g/cm3 Treatment of intact virions by chymotrypsin (CHT) digestion in vitro converts them to subviral particles (SVP) having characteristics which are determined by the species of monovalent cation present during the digestion In the presence of Cs+ ions, CHT converts the virions to SVP of mean diameter 51 nm and density 143 to 144 g/cm3 In the presence of K+ ions, the conversion is to SVP of diameter 51 nm and density 139 to 140 g/cm3 The SVP made in the presence of either Cs+ or K+ possess an extremely active RNA polymerase and nucleoside triphosphate phosphohydrolase (NTPase) activity in vitro and are resistant to further digestion by CHT Treatment of intact virions with CHT in the presence of Na+ or Li+ ions results in their conversion to SVP of mean diameter 64 nm and density 137 to 138 g/cm3 Such SVP are not active in in vitro RNA synthesis or NTP hydrolysis and are resistant to further digestion by CHT even during prolonged exposure to high concentrations of enzyme Addition of Cs+ or K+ ions to the digestion mixture allows conversion of the 64-nm diameter SVP to 51-nm diameter SVP in which the RNA polymerase and NTPase are active in vitro Analysis of the proteins present in intact virions and in the different SVP reveals clear differences which indicate that the conversions are accomplished by removal or cleavage of particular species of polypeptides

Time Distribution of Positron Annihilation in Liquids and Solids

Abstract: The time distribution of the annihilation radiation emerging from liquids and solids, following the absorption by the samples of fast positrons, has been studied by the delayed coincidence method. The mean life of positrons in metals is found to be about 1.5\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}10}$ sec, nearly independent of the metal chosen. Some simple crystals behave similarly, but many amorphous substances, both solid and liquid, show a complex time decay in which about $\frac{2}{3}$ of the positrons annihilate with mean life a few times ${10}^{\ensuremath{-}10}$ second, and the remaining $\frac{1}{3}$ with mean life from 0.45\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}9}$ sec to 3.5\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}9}$ sec, depending on the substance. This longer lifetime is shown to decrease, in general, as the sample is cooled. Placing the sample in moderate electric and magnetic fields has no detectable effect. The long-delayed radiation is shown to be similar in energy and angular distribution to the more prompt component. Tentative interpretations of these facts are given, but some points still await a full explanation.