Showing papers by "Chalk River Laboratories published in 1975"

Isolation of cold-sensitive Chinese hamster cells.

Abstract: Six cold-sensitive variants have been isolated from Chinese hamster ovary cells by the BUdR-visible light selection technique. The properties of one of these lines have been studied in detail. This line stops dividing immediately after a shift from 39° C to 33° C though its doubling time at 39° C is only slightly longer than that of wild-type cells. The rates of DNA and protein synthesis are severely reduced at 33° C, but the rate of RNA synthesis is not significantly different from wild-type cells. This line may be defective in protein synthesis, but the results of sedimentation analysis indicate that it probably has normal ribosomal subunit assembly.

The Use of Molecular Ions for Implantation Studies in Si and Ge

Abstract: Results of an investigation of the lattice disorder resulting from equal atom dose implants of molecular and atomic ions in Si and Ge are presented. In each case, the molecular ion implants had the same energy per atom and were performed at the same atomic flux and fluence as the atomic ion implants. With heavy ions (As, Sb, Te and Bi), the molecular beam produces roughly 50% more damage than the atomic beam, indicating that damage production depends not only on the amount but also on the localized concentration of deposited energy. Preliminary experiment with lighter ions (H, D) in both Si and Ge do not show this mole cub effect. The significance of these results is discussed in relation to the average energy density within the collision cascade.