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81.
John D. Wilkins 《Journal of organometallic chemistry》1974,65(3):383-389
The reactions of MexMCl5?x, x = 1,2,3, M = Nb, Ta with RNCS, R = Me, Ph have been studied, and products of the types MCl4 [NRC(S)Me], MeTaCl3[NRC(S)Me] and NbCl3[NMeC(S)Me]2 containing thioacetamide groups, arising from insertion into the metalcarbon bonds have been characterised.Reactions with MeSCN yield the complexes MeMCl4 · MeSCN and Me2MCl3 · MeSCN; the presence of S- and N-bonded isomers is indicated by the infrared spectra. 相似文献
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Numerical Algorithms - We study a class of general purpose linear multisymplectic integrators for Hamiltonian wave equations based on a diamond-shaped mesh. On each diamond, the PDE is discretized... 相似文献
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M J Tomlinson J R Scott C L Wilkins J B Wright W E White 《Journal of mass spectrometry : JMS》1999,34(9):958-968
Collision-induced dissociation of metal-cationized N-CBZ-Gly-Pro-Gly-Pro-Ala was studied by Fourier transform mass spectrometry. Lithium-, sodium-, potassium- and rubidium-cationized peptide species were generated by matrix-assisted laser desorption/ionization (MALDI) using 2,5-dihydroxybenzoic acid as matrix, together with appropriate metal salts. The experimental mass spectrometric results were interpreted with the aid of Monte Carlo conformational searches using the Amber(*) force field, together with ab initio molecular orbital calculations with Gaussian-94 for the singly lithium- and potassium-cationized peptides. It is concluded that metal coordination plays a key role in guiding the gas-phase fragmentation of the cationized peptide. In contrast to lithium and sodium, potassium and rubidium apparently do not coordinate to the C-terminal carbonyl. When the peptide is cationized with the two smaller alkali metals, losses corresponding to alanine and CBZ are observed, while the coordination of potassium and rubidium results in only CBZ loss upon dissociation. 相似文献
87.
Dhimankrishna Ghosh Dustin Lippert Oleg Krokhin John P. Cortens John A. Wilkins 《Journal of mass spectrometry : JMS》2010,45(1):1-25
The present study was initiated to define the composition of the membrane proteome of the Natural Killer (NK) like cell line YTS. Isolated membranes were treated with reagents that have been reported to remove peripheral membrane proteins. Additional steps involving trifluoroethanol (TFE) were introduced in an effort to remove remaining nonintegral membrane proteins. This treatment resulted in the release of a subset of proteins without any apparent disruption of membrane integrity. The membranes were solubilized and digested with trypsin in 25% TFE. The resulting peptides were separated using an off‐line two‐dimensional reversed phase LC technique at alkaline and acidic pHs. Mass spectrometric analysis identified 1843 proteins with high confidence scores. On the basis of the presence of transmembrane regions or evidence of posttranslational modifications and prediction algorithms, approximately 40% of the identified proteins were predicted as plausible membrane proteins. The remaining species were largely involved in cellular processes and molecular functions that could be predicted to be transiently associated with membranes. The analytical approaches presented in this study offer robust generic methods for the identification and characterization of membrane proteins. These observations highlight the fact that the membrane is a dynamic entity that is composed of integral and stably associated proteins. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
88.
Thompson M Wilkins SJ Compton RG Viles HA 《Journal of colloid and interface science》2003,260(1):204-210
The extent of passivation of calcite toward dissolution by aqueous acids arising from polymeric coatings based on polyacrylic acid or polyacrylonitrile is evaluated using a channel flow cell technique with microdisc electrode detection. In situ passivation with polyacrylic acid leads to a reduction in the reactivity of calcite toward acid attack with a reduction in the rate constant by up to an order of magnitude compared with untreated calcite. Ex situ passivation with polyacrylic acid for 24 h results in good coverage of the calcite by the polymer but it is shown to erode from the surface when exposed to an aqueous acid solution. In contrast, polyacrylonitrile is demonstrated to form a regular coating after exposure for just 1 h and offers robust potent protection from aqueous acid attack. 相似文献
89.
A microfabricated glucose biosensor based on an amperometeric hydrogen peroxide electrode has been developed. A sol-gel layer with 5 A pore size and 2 mum thickness was used as the glucose oxidase entrapping matrix. The sol-gel matrix formed over the silicon-based sensor has good mechanical and chemical stability, and the ability to entrap a large amount of enzyme. The miniaturized electrode sensing system is composed of platinum as both working and counter electrodes and silver as a reference electrode. Nafion(R) coating was applied as the interference limiting layer. A series of technologies, such as standard photolithography, electron beam evaporation and image reverse lift-off were utilized for mass production allowing 143 electrodes to be produced at the same time. The effect of oxidable interferences was <10% of the background value of the sensor response. Calibration tests of a series of individual sensors manufactured from the same silicon wafer and dip coated in the same conditions, showed a highly reproducible response characteristics (linear range up to 500 mg dl(-1) and mean sensitivity of 0.54+/-0.14 nA mg(-1) dl(-1) (n=10)). 相似文献
90.