Chalk River Laboratories

About: Chalk River Laboratories is a based out in . It is known for research contribution in the topics: Neutron diffraction & Neutron scattering. The organization has 2297 authors who have published 2700 publications receiving 73287 citations.

Accumulation of spontaneous γH2AX foci in long-term cultured mesenchymal stromal cells.

Abstract: Expansion of mesenchymal stromal/stem cells (MSCs) used in clinical practices may be associated with accumulation of genetic instability. Understanding temporal and mechanistic aspects of this process is important for improving stem cell therapy protocols. We used γH2AX foci as a marker of a genetic instability event and quantified it in MSCs that undergone various numbers of passage (3-22). We found that γH2AX foci numbers increased in cells of late passages, with a sharp increase at passage 16-18. By measuring in parallel foci of ATM phosphorylated at Ser-1981 and their co-localization with γaH2AX foci, along with differentiating cells into proliferating and resting by using a Ki67 marker, we conclude that the sharp increase in γH2AX foci numbers was ATM-independent and happened predominantly in proliferating cells. At the same time, gradual and moderate increase in γH2AX foci with passage number seen in both resting and proliferating cells may represent a slow, DNA double-strand break related component of the accumulation of genetic instability in MSCs. Our results provide important information on selecting appropriate passage numbers exceeding which would be associated with substantial risks to a patient-recipient, both with respect to therapeutic efficiency and side-effects related to potential neoplastic transformations due to genetic instability acquired by MSCs during expansion.

Vacancy properties in Cu3Au-type ordered fcc alloys

Abstract: A theory of vacancy formation in Cu3Au-type ordered fcc alloys is presented. The present theory, which is based on the pairwise bonding model, is found to be in good agreement with the experimentally observed vacancy properties in ordered Cu3Au and Ni3Al. Various shortcomings in the previous theoretical calculations have also been identified.

High-spin states in 107 Pd, 108 Pd, and 109 Ag

Abstract: High-spin states in 107,108Pd and 109Ag have been studied by charged-particle-γ, γ-γ, and charged-particle-γ-γ coincidence measurements of heavy-ion fusion-evaporation reactions. The high-spin level schemes of these nuclides have been significantly extended and new deformed rotational bands have been found in each nuclide. These bands exhibit the general property of back bends corresponding to the rotational alignment of a pair of h11/2 quasineutrons. Band properties are compared with predictions of the cranked shell model and total Routhian surface calculations. The properties of the yrast and near-yrast bands of all three nuclides are generally consistent with predictions of moderate (β2 = 0.2) prolate deformation.