Sulfur-33 NQR investigation of the electric-field-gradient tensor in an organosulfur compound

Abstract33S nuclear quadrupole resonance (NQR) frequencies of 33S-enriched S-4-phenyl 4-toluenethiosulfonate were observed in the range of 22.96–23.31 MHz at temperatures between 110 and 300 K. A single sharp signal was observed at all the temperatures. The two-dimensional (2D) nutation echo method was applied at 150 K, providing the 33S electric field gradient (EFG) tensor information, the quadrupolar coupling constant, CQ, of 42.3 MHz and the asymmetry parameter, ηQ, of 0.80(9). Quantum chemical calculations were performed to obtain the 33S EFG tensor orientations with respect to the molecular frame.

Focal Length Measurement of Lens Based on Linear Array CCD

Focal length of lens is an important parameter to determine the relationship between objective and image. It must be measured accurately. The traditional method of using optical bench to measure the focal length of lens has big man-made errors. So we used linear array CCD camera instead of eyes as the receiver to measure the focal length of lens in this paper. Based on the theory of point spread function, it firstly determined the evaluation function of focal plane. With the threshold method, it determined the location coordinate of sharp signal. Then it proved the feasibility of this scheme through experiment. Finally we compared the experimental data obtained with this method with the experimental data obtained with traditional method, which showed that it was more accurate to measure the focal length of lens with this method.

Cs Speciation in Cements

ABSTRACTSolid-state 133Cs magic angle spinning nuclear magnetic resonance (MAS NMR) measurements have been used to investigate Cs speciation in cements designed for immobilizing low-level nuclear wastes. Cs in ordinary Portland cement cured for only 10 days at room temperature appears to only inhabit aqueous solutions, as evidenced by a sharp signal with no sidebands, whether or not substantial quantities of blast furnace slag or silica fume are present. No significant 133Cs spectral differences were observed when slag or silica fume were present for curing periods of 10 days, but differences due to Cs partly inhabiting crystalline sites instead of water solutions were observed after 12 months in the slag-containing cement. Pre- incorporation of Cs in various zeolites, followed by mixing the zeolites into the cement, leads to enhanced Cs retention in the cement when it is subject to water leaching at 25°C.

Evaluation of a Colorimetric PCR-Based Assay To Diagnose Plasmodium falciparum Malaria in Travelers

New diagnostic tests are needed to facilitate the diagnosis ofPlasmodium falciparum malaria in the returned traveler. We performed a blinded evaluation of a nonisotopic colorimetric PCR-based assay (Digene SHARP Signal System) and compared the results with those obtained by microscopy and nested PCR for the detection of P. falciparum malaria in 150 febrile travelers. By using nested PCR as the reference standard, the colorimetric assay had a sensitivity of 100% and a specificity of 95.4% for the detection of P. falciparum. This PCR-based nonisotopic assay is a rapid, sensitive, and specific method for the detection of falciparum malaria in returned travelers.