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.

Diffuse colonies of human skin fibroblasts in relation to cellular senescence and proliferation.

Abstract: Development of personalized skin treatment in medicine and skin care may benefit from simple and accurate evaluation of the fraction of senescent skin fibroblasts that lost their proliferative capacity We examined whether enriched analysis of colonies formed by primary human skin fibroblasts, a simple and widely available cellular assay, could reveal correlations with the fraction of senescent cells in heterogenic cell population We measured fractions of senescence associated β-galactosidase (SA-βgal) positive cells in either mass cultures or colonies of various morphological types (dense, mixed and diffuse) formed by skin fibroblasts from 10 human donors Although the donors were chosen to be within the same age group (33-54 years), the colony forming efficiency of their fibroblasts (ECO-f) and the percentage of dense, mixed and diffuse colonies varied greatly among the donors We showed, for the first time, that the SA-βgal positive fraction was the largest in diffuse colonies, confirming that they originated from cells with the least proliferative capacity The percentage of diffuse colonies was also found to correlate with the SA-βgal positive cells in mass culture Using Ki67 as a cell proliferation marker, we further demonstrated a strong inverse correlation (r=-085, p=002) between the percentage of diffuse colonies and the fraction of Ki67+ cells Moreover, a significant inverse correlation (r=-094, p=00001) between the percentage of diffuse colonies and ECO-f was found Our data indicate that quantification of a fraction of diffuse colonies may provide a simple and useful method to evaluate the extent of cellular senescence in human skin fibroblasts

Neutron scattering study of the classical antiferromagnet MnF2: a perfect hands-on neutron scattering teaching courseSpecial issue on Neutron Scattering in Canada.

Abstract: We present the classical antiferromagnet MnF2 as a perfect demonstration system for teaching a remarkably wide variety of neutron scattering concepts. The nature of antiferromagnetism and the magne...

Structural Phase Behavior of High-Concentration, Alignable Biomimetic Bicelle Mixtures

Abstract: The structures of bicelle mixtures composed of dimyristoyl and dihexanoyl phosphatidylcholines (DMPC and DHPC) with DMPC/DHPC molar ratios of 3.2 and 5 are characterized using polarized optical microscopy (POM) and small angle neutron scattering (SANS). Three phases, isotropic (I), chiral nematic (N*) and smectic (S) are observed as temperature (T) varies from 10 to 70 °C. The structure of the magnetically alignable N phase, which was previously considered to be made up of discoidal micelles, is found to be composed of ribbons. Doping with the charged lipid, dimyristoyl phosphatidylglycerol (DMPG), which has the same 14:0 hydrocarbon chains as DMPC, results in a structural change of the aggregates where only the isotropic and smectic phases are observed. The smectic phase for the mixtures doped with DMPG is shear-alignable and follows one-dimensional swelling. However, at high-T zwitterionic DMPC/DHPC mixtures form multi-lamellar vesicles (MLV) with a relatively constant lamellar spacing of 66 A, independent of water content.

Réponse adaptative au rayonnement ionisant des fibroblastes de peau humaine - Augmentation de la vitesse de réparation de l'ADN et variation de l'expression des gènes

Abstract: Les doses faibles et les debits de dose faibles de rayonnement ionisant augmentent la vitesse de reparation de l'ADN des fibroblastes de peau humaine et protegent les cellules contre la formation de micronoyaux par le rayonneraient. Des expositions chroniques reduisent la teneur en ARNm des genes topoisomerase II et FACC-1 (anemie de Fanconi, groupe C)