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.

Microprojectile-DNA delivery in conifer species: factors affecting assessment of transient gene expression using the β-glucuronidase reporter gene.

Abstract: The Biolistic® microprojectile DNA-delivery method was used to test the usefulness in conifers of eight gene constructs based on the 35S promoter, the AMV translational enhancer, and gene fusion between the P-glucuronidase and the neomycin phosphotransferase II genes. The evaluation was done with embryogenic cells of Picea glauca, where the relative strengths of the promoters were 35S-35S-AMVE>35S-AMVE>35S-35S>35S as evaluated by transient gene expression. The fusion gene of GUS and NPT II gave lower levels of transient gene expression than the unfused GUS gene as detected by X-GLU histochemical assays. Experiments comparing the EM promoter of wheat and the 35S-35S-AMVE promoter (with and without fusion between GUS and NPT II) were done in Picea rubens, P. mariana, P. glauca, and Larix x eurolepis. The unfused gene with the 35S-35S-AMVE promoter gave higher levels of transient gene expression than the fused GUS-NPT II gene. The fluorescent MUG assay was more sensitive than the histochemical X-GLU assay to detect the activity of the β-glucuronidase gene.

Anomalous weak magnetism in superconducting YBa2Cu3O6+x.

Abstract: For some time now, there has been considerable experimental and theoretical effort to understand the role of the normal-state “pseudogap” phase in underdoped high-temperature cuprate superconductors. Recent debate has centered on the question of whether the pseudogap is independent of superconductivity. We provide evidence from zero-field muon spin relaxation measurements in YBa2Cu3O6+x for the presence of small spontaneous static magnetic fields of electronic origin intimately related to the pseudogap transition. Our most significant finding is that, for optimal doping, these weak static magnetic fields appear well below the superconducting transition temperature. The two compositions measured suggest the existence of a quantum critical point somewhat above optimal doping.

ERDA with very heavy ion beams

Abstract: The use of very heavy ion beams such as 127I or 197Au with 1–2 MeV/u makes ERDA (elastic recoil detection analysis) a quite universal technique for thin film analysis capable of analyzing simultaneously light and heavy elements including H with almost constant sensitivity Due to the strong increase of the recoil cross section with the projectile atomic number typically less than 1012 ions are required to get sensitivities in the 100 ppm range Detector systems with particle identification are advantageous for ERDA, which can be improved additionally regarding depth resolution and detection efficiency, if the kinematic energy spread is corrected The characteristic features of heavy ion ERDA will be briefly outlined and illustrated by several examples using a position sensitive detector system Some general problems and limitations, which are caused by heavy ion beams, will also be discussed

NDE reliability gains from combining eddy-current and ultrasonic testing

Abstract: We investigate statistical methods for combining the results of two complementary inspection techniques, eddy-current and ultrasonic testing. The reliability of rejection/acceptance decisions based on combined information is compared with that based on each inspection technique individually. Combination methods, ranging from a simple OR of individual decisions to more sophisticated data fusion algorithms, are assessed. We find that the measured reliability increases with the amount of information incorporated in the decision.