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.

Tocopherol Activity Correlates with Its Location in a Membrane: A New Perspective on the Antioxidant Vitamin E

Abstract: We show evidence of an antioxidant mechanism for vitamin E which correlates strongly with its physical location in a model lipid bilayer. These data address the overlooked problem of the physical distance between the vitamin’s reducing hydrogen and lipid acyl chain radicals. Our combined data from neutron diffraction, NMR, and UV spectroscopy experiments all suggest that reduction of reactive oxygen species and lipid radicals occurs specifically at the membrane’s hydrophobic–hydrophilic interface. The latter is possible when the acyl chain “snorkels” to the interface from the hydrocarbon matrix. Moreover, not all model lipids are equal in this regard, as indicated by the small differences in vitamin’s location. The present result is a clear example of the importance of lipid diversity in controlling the dynamic structural properties of biological membranes. Importantly, our results suggest that measurements of aToc oxidation kinetics, and its products, should be revisited by taking into consideration the ...

Floppy modes in crystalline and amorphous silicates

Abstract: In this chapter we have outlined a number of feature of the RUM flexibility of crystalline networks of linked tetrahedra and octahedra. As we have stressed, the initial value of the RUM approach was to give an understanding of the origin and characteristics of displacive phase transitions. However, since the RUM approach also gives use the means to understand the whole area of low-frequency dynamics of network structures containing rigid units, and the insights from this have been useful to understand dynamically disordered crystalline phases, zeolites, and now silica glass.

Spin glass behavior in URh2Ge2

Abstract: URh{sub 2}Ge{sub 2} occupies an extraordinary position among the heavy-electron 122 compounds, by exhibiting a previously unidentified form of magnetic correlations at low temperatures instead of the usual antiferromagnetism. Here we present new results of ac and dc susceptibilities, specific heat, and neutron diffraction on single-crystalline as-grown URh{sub 2}Ge{sub 2}. These data clearly indicate that crystallographic disorder on a local scale produces spin glass behavior in the sample. We therefore conclude that URh{sub 2}Ge{sub 2} is a 3D Ising-like, random-bond, heavy-fermion spin glass. {copyright} {ital 1997} {ital The American Physical Society}