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131.
阴阳离子型表面活性剂双水相萃取色氨酸衍生物和牛血清白蛋白 总被引:7,自引:0,他引:7
溴化十二烷基三乙胺(C12NE)和十二烷基硫酸钠(SDS)在一定条件下混合可以形成具有清晰界面的两个水相,称为阴阳离子型表面活性剂双水相。作者研究了利用该双水相萃取3种色氨酸衍生物和牛血清白蛋白的可能性.文中采用工作曲线校正扣除表面活性剂背景的影响,萃取结果准确可信。 相似文献
132.
Takashi Hayashita Akiyo Yamauchi Ai-Jun Tong Jong Chan Lee Bradley D. Smith Norio Teramae 《Journal of inclusion phenomena and macrocyclic chemistry》2004,50(1-2):87-94
The design and function of novel supramolecular fluoroionophore/cyclodextrin (CyD) complex sensors for ion and molecule recognition in water are reviewed. For the crown ether fluoroionophore/-CyD complex, the dimerization of the fluoroionophore inside the -CyD is found to be selectively promoted by alkali metal ion binding, thereby resulting in metal-ion-selective pyrene dimer emission in water. This supramolecular function is successfully utilized in the design of a podand fluoroionophore/-CyD complex for sensing toxic lead ion in water. The boronic acid fluoroionophore/-CyD complex binds sugars and produces increased fluorescence emission in water. The response mechanism appears to be due to the suppression of the photoinduced electron transfer (PET) from pyrene donor to trigonal phenylboronic acid acceptor. This is a novel emission function provided by the boronic acid fluoroionophore/-CyD complex sensors in water. 相似文献
133.
Zhang Guozhen Tetsuya Shichi Tong Zhiwei Katsuhiko Takagi 《Research on Chemical Intermediates》2007,33(1-2):155-160
A new organic/inorganic hybrid material was prepared by the polymerization of bis(hydroxyethyl) terephthalate (BHET) with a layered niobate compound, H4Nb6O17, modified by 11-aminoundecanoic acid (AUA). The hybrid polymer films of BHET with H4Nb6O17/AUA exhibited favorable characteristics, particularly of being optically clear, indicating the exfoliation and homogeneous dispersion of H4Nb6O17 into the PET/niobate hybrid. 相似文献
134.
Photoinduced shape deformation of colloidal spheres made of an amphiphilic azo polymer has been demonstrated in this work. The polymer contains the donor-and-acceptor-type azobenzene chromophores and can form uniform colloidal spheres by dropwise adding water into its THF solution. When the colloidal spheres obtained were exposed to the interfering p-polarized Ar+ laser beams (150 mW/cm2), the colloidal spheres changed to prolates (i.e., "rugby-balls"), "spindles", and finally "rods", depending on the irradiation times. The elongated direction of the spheres was observed to be the same as the polarization direction of the laser beam. The average major-to-minor ratio of the ellipsoids could be easily adjusted by controlling the irradiation time. The deformation effect observed in this work can offer a new way to prepare nonspherical colloids from colloidal spheres and will shed new light on the correlation between the photodriven shape deformation and photoinduced surface relief gratings for the same type of polymers. 相似文献
135.
Brownian dynamics simulations with hydrodynamic interactions are conducted to investigate the self-diffusion of charged tracer particles in a dilute solution of charged polymers, which are modeled by bead-spring chains. The Debye-Hückel approximation is used for the electrostatic interactions. The hydrodynamic interactions are implemented by the Ewald summation of the Rotne-Prager tensor. Our simulations find that the difference in short- and long-time diffusivities is very slight in uncharged short-chain solutions. For charged systems, to the contrary, the difference becomes considerable. The short-time diffusivity is found to increase with increasing chain length, while an opposite behavior is obtained for the long-time diffusivity. The former is attributed to the hydrodynamic screening among beads in a same chain due to the bead connectivity. The latter is explained by the memory effect arising from the electrostatic repulsion and chain length. The incorporation of hydrodynamic interactions improves the agreement between the simulation prediction and the experimental result. 相似文献
136.
137.
Y. C. Tong 《Journal of heterocyclic chemistry》1980,17(2):381-382
Methods for the preparations of 1H-imidazo[4,5-b]pyrazine-2-carboxylic acid and derivatives are reported. 相似文献
138.
Polymer-supported phosphine ligand 3b derived from ferrocene was prepared,and applied in palladium-catalyzed Suzuki- Miyaura reactions.A range of aryl bromides can couple with phenylboronic acid to obtain corresponding biaryls in excellent yields. The recycling of the polymer-bound catalyst was tested without adding palladium. 相似文献
139.
140.
Yingkai Zhang 《Theoretical chemistry accounts》2006,116(1-3):43-50
This perspective article mainly focuses on the development and applications of a pseudobond ab initio QM/MM approach to study enzyme reactions. The following aspects of methodology development are discussed: the approaches for the QM/MM covalent boundary problem, an efficient iterative optimization procedure, the methods to determine enzyme reaction paths, and the approaches to calculate free energy change in enzyme reactions. Several applications are described to illustrate the capability of the methods. Finally, future directions are discussed. 相似文献