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141.
Alphonse Ekouya Raymond Calas Jacques Dunogues Claude Biran Norbert Duffaut 《Journal of organometallic chemistry》1979,177(1):137-144
Aliphatic saturated amides treated with Me3SiCl/Li/THF were found to react in two ways. Either alkoxysilanes, mono- or di-silylated at the functional carbon, or C-silylated amines were obtained dependent of the original amide structure and the experimental conditions. (Me3Si)2CHN(SiMe3)2 exhibited Physicochemical properties that are particular for hindered rotation about the CN bond. A general mechanism is proposed to explain these results. 相似文献
142.
143.
Bao‐Shiang Lee Sangeeth Krishnanchettiar Syed Salman Lateef Nabila Salman Lateef Shalini Gupta 《中国化学会会志》2006,53(3):745-750
Avidin functional affinity electrophoresis (AFAEP) is substituted for an avidin affinity column (AAC) to capture biotinylated peptides in the Isotope‐Coded Affinity Tagging (ICAT) technique which is a valuable tool in quantitative proteomics. In this new technique, the AFAEP‐captured ICAT‐labeled biotinylated peptides are extracted with the biotin tag intact from the polyacrylamide gel piece with aqueous 95% formamide (pH 8.2) at 65 °C for 20 min, and then detected by a matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometer. Bovine serum albumin (BSA) and the 12C‐ and 13C‐ICAT reagents are used to test this AFAEP‐ICAT technique. The results show that both AFAEP and AAC methods provide quantitative information of the relative amounts of 12C‐ and 13C‐ICAT‐labeled biotinylated tryptic peptides of BSA in a sample. Compared with AAC, the AFAEP is cheaper to perform, more stringent in capturing the biotinylated peptides, and capable of simultaneously processing multiple samples. 相似文献
144.
Hydrophobic interaction chromatography coupled online with chemical vapour atomic fluorescence spectrometry (HIC-CVGAFS) has been optimized for the analysis of thiolic proteins in denaturing conditions. Proteins are pre-column simultaneously denatured and derivatized in phosphate buffer solution containing 8.0 mol dm−3 urea and p-hydroxymercurybenzoate (PHMB) and the derivatized denatured proteins are separated on a silica HIC Eichrom Propyl column in the presence of 8.0 M urea in the mobile phase. Post-column online reaction of derivatized denatured proteins with bromine, generated in situ by KBr/KBrO3 in HCl medium, allowed the fast conversion of the uncomplexed PHMB and of the PHMB bound to proteins to inorganic mercury also in presence of urea. Hg2+, present in solution as Hg2+-urea complex, is selectively detected by AFS in a Ar/H2 miniaturized flame after sodium borohydride reduction to Hg. Under optimized conditions, online bromine treatment gives a 100±2% recovery of both free and protein-complexed PHMB. Denatured glyceraldehyde-3-phosphate dehydrogenase, aldolase, lactate dehydrogenase, trioso phosphate isomerase and β-lactoglobulin have been examined. As the sensitivity and limit of detection of proteins in the HIC-CVGAFS apparatus depends on number of SH groups reacting with PHMB, the denaturation process, which increases the number of PHMB-reactive thiolic groups in proteins, improves the analytical performances of the described system in protein analysis. The detection limit for the denatured proteins examined was found in the range of 10−10-10−12 mol dm−3, depending on the considered protein, with linear calibration curves spanning over four decades of concentration. 相似文献
145.
DNA works as hereditary material and plays vital role in life science. The study of the binding of small molecules complex to DNA has been the focus of intense investigation, owning to their stereo and sequence specific interaction with the double helix1-… 相似文献
146.
Electrosorption of hydrogen into palladium-gold alloys 总被引:1,自引:0,他引:1
M. Łukaszewski K. Kuśmierczyk J. Kotowski H. Siwek A. Czerwiński 《Journal of Solid State Electrochemistry》2003,7(2):69-76
Hydrogen electrosorption into Pd-Au alloys has been studied in acidic solutions (1 M H2SO4) using cyclic voltammetry. Pd-Au electrodes with limited volume were prepared by electrochemical co-deposition. It was found
that the maximum H/(Pd+Au) ratios decrease monotonically with increasing gold content and reach zero at ca. 70 at% Au. Similarly
to the case of Pd limited volume electrodes, two peaks in the hydrogen region, corresponding to two types of sorbed hydrogen,
are observed on voltammograms for Pd-rich alloys. The hydrogen capacity, H/(Pd+Au), measured electrochemically, depends on
the sweep rate in the cyclic voltammetry experiments, which suggests that two different mechanisms for hydrogen desorption
from the Pd-Au alloy are possible. After a strong decrease of Pd concentration at the electrode surface, caused by long cyclic
polarization to sufficiently anodic potentials, the amount of absorbed hydrogen is still significant for alloys initially
rich in Pd. The results obtained from CO adsorption experiments suggest that only Pd atoms are active in the hydrogen absorption/desorption
process.
Electronic Publication 相似文献
147.
Lead zirconate titanate (PZT) thin films were deposited on Pt/Ti/SiO2/Si and interlayer/Pt/Ti/SiO2/Si substrate by radio frequency (r.f.) magnetron sputtering with a Pb1.1Zr0.53Ti0.47O3 target. The crystallization of the PZT thin films was formed only by substrate temperature. When interlayer (PbO/TiO2) was inserted between the PZT thin film and the Pt electrode, the grain growth and processing temperature of the PZT thin films were considerably improved. Compared to PZT/Pt structure, the dielectric constant and polarization properties of the PZT/interlayer/Pt structure were fairly improved. In particular, PZT/interlayer/Pt at the substrate temperature of 400 °C showed prevalent ferroelectric properties (r=475.97, tanδ=0.0591, Pr=23 μC/cm2). As a result of an X-ray photoelectron spectroscopy (XPS) depth-profile analysis, it was found that PZT/interlayer/Pt deposited only by substrate temperature without the post-annealing process via r.f. magnetron sputtering method remained independent of each other regardless of substrate temperatures. 相似文献
148.
The complexes of poly(methacrylic acid-co-methyl methacrylate) network with poly(ethylene glycol) stabilized byhydrogen bonds were prepared. By introducing the poly(ethylene glycol), a large difference in storage modulus below andabove the glass transition temperature occurred and the complexes exhibited shape memory behaviors. The morphology ofcomplexes was studied by using DSC, WAXD, and DMA. The results indicate that the fixed phase of this kind of novelshape memory materials is the network, and the reversible phase is the amorphous state of PEG:PMAA complex phase. Theshape recoverability almost reaches 100%. This type of complexes can be regarded as a novel shape memory network. 相似文献
149.
多色蓝在核酸分子上的Langmuir聚集吸附 总被引:4,自引:0,他引:4
用微相吸附-光谱修正(MPASC)新技术研究核酸与多色蓝(PCB)探针分子间的相互作用,分析核酸分子内双静电膜的形成与Langmuir吸附的关联性.通过pH 7.24的介质核酸-PCB反应的光谱研究,测定了结合产物的物理化学参数:结合比1PCB:2DNA-PCB、1PCB:3RNA-PCB, 平衡常数KDNA-PCB=5.42×104, KRNA-PCB=2.82×104,摩尔吸收系数ε(DNA-PCB, 625 nm)=5.65×103(mo1-1•L )•cm-1, ε(RNA-PCB, 625 nm)=3.85×103 (mol-1•L)•cm-1.结果表明, RNA分子仅形成约60%双螺旋结构链,核酸双螺旋每一周期的负静电沟最大聚集10个PCB分子.该吸附反应用于核酸样品测定,结果良好. 相似文献
150.