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91.
Beattie DA Fraenkel R Winget SA Petersen A Bain CD 《The journal of physical chemistry. B》2006,110(5):2278-2292
Infrared-visible sum-frequency spectroscopy has been used to record the vibrational spectrum of a zinc arachidate monolayer at the interface between a sapphire prism and a fused silica lens. Spectra have been recorded for the monolayer deposited on the prism before, during, and after contact, and as a function of increasing pressure. Sum-frequency spectra are reported of the monolayer under sliding contact. The monolayer is found to be resistant to pressure- and shear-induced conformational disorder. However, frequency shifts, drops in peak intensities, and changes in peak intensity ratios have been observed as the monolayer is placed in contact between the prism and the lens. Transfer of monolayer material between the two surfaces is observed and is confirmed by spectra obtained with a monolayer deposited on the surface of the lens rather than the prism. On one face of the sapphire prism, the monolayer reconstructs to a low symmetry layer, probably due to epitaxy. The epitaxial structure disappeared in contact. Existing models for calculating sum-frequency spectra have been extended to include unit cells containing two molecules and torsion about the terminal C-C bond. This model can explain some, but not all, of the experimental observations. 相似文献
92.
14‐Vertex Heteroboranes with 14 Skeletal Electron Pairs: An Experimental and Computational Study 下载免费PDF全文
Dr. Alasdair P. M. Robertson Nicholas A. Beattie Dr. Greig Scott Dr. Wing Y. Man John J. Jones Prof. Stuart A. Macgregor Dr. Georgina M. Rosair Prof. Alan J. Welch 《Angewandte Chemie (International ed. in English)》2016,55(30):8706-8710
Three isomers of [(Cp*Ru)2C2B10H12], the first examples of 14‐vertex heteroboranes containing 14‐skeletal electron pairs, have been synthesized by the direct electrophilic insertion of a {Cp*Ru+} fragment into the anion [4‐Cp*‐4,1,6‐RuC2B10H12]?. All three compounds have the same unique polyhedral structure having an approximate Cs symmetry and featuring a four‐atom trapezoidal face. X‐ray diffraction studies could confidently identify only one of the two cage C atoms in each structure. The other C atom position has been established by a combination of i) best fitting of computed and experimental 11B and 1H NMR chemical shifts, and ii) consideration of the lowest computed energy for series of isomers studied by DFT calculations. In all three isomers, one cage C atom occupies a degree‐4 vertex on the short parallel edge of the trapezium. 相似文献
93.
Urgast DS Ou O Gordon MJ Raab A Nixon GF Kwun IS Beattie JH Feldmann J 《Analytical and bioanalytical chemistry》2012,402(1):287-297
The kinetics of zinc absorption, metabolism and excretion is extensively studied by nutritionists. Stable isotopes of zinc
can be used to identify body zinc compartments that have different turnover kinetics. Since the compartments might belong
to physiological subsections of different organs, there is a need for microsampling analysis to determine isotope ratios of
the trace element zinc in tissue samples. Here, we study the feasibility to use laser ablation coupled to quadrupole ICP-MS
for the determination of zinc tracers given to rats at different time points with the aim to generate isotope ratio bioimages
of heart tissue. A double tracer (70Zn and 67Zn) experiment with rats was designed to label the exchangeable zinc pool as well as the stable zinc pool. The isotope ratios
determined by laser ablation ICP-MS were evaluated by additional measurements of tissue digests. Accumulated tracers which
made up more than 0.1% of total zinc could be identified in the tissues of the treated rats. It was established that at least
50 measurements from the microsampling were necessary to distinguish between controls and a tracer treated rat resulting in
reduced resolution of the bioimage. With the parameters used, features in the tissue thin sections of at least 250 μm2 in size are necessary to detect the incorporation of a tracer. When different time points have to be measured, higher precisions
are required and therefore a larger area needs to be ablated (1 mm2). Using the bioimages and pool measurements from one physiological feature, it was possible to show that the aorta cell walls
incorporate the zinc tracer at the different time points. 相似文献
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For H a quasitriangular Hopf algebra, S 2, the square of the antipode is the inner automorphism induced by the Drinfeld element u, and S 4 is the inner automorphism induced by the grouplike element g = uS(u)?1. For H finite dimensional, results of Drinfeld and Radford express g in terms of the modular elements of H. This note supplies another proof which replaces the requirement of finite dimensionality with existence of a nonzero integral for H in H*. Similar results hold for the infinite dimensional coquasitriangular case; here we supply some interesting examples. 相似文献
98.
Synthesis of 2-C-fluoromethyl-myo-inositol from DL-l-O-benzyl-2-oxiranyl-3, 4, 5, 6-tetra-O-benzyl-myo-inositol is described. 相似文献
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Separately continuous bihomomorphisms on a product of convergence or topological groups occur with great frequency. Of course, in general, these need not be jointly continuous. In this paper, we exhibit some results of Banach-Steinhaus type and use these to derive joint continuity from separate continuity. The setting of convergence groups offers two advantages. First, the continuous convergence structure is a powerful tool in many duality arguments. Second, local compactness and first countability, the usual requirements for joint continuity, are available in much greater abundance for convergence groups. 相似文献