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981.
HongWU ZhongJIANG SongWeiXU ShuFangHUANG 《中国化学快报》2003,14(4):423-425
CO2 is converted to nethanol through an enzymatic approach using formate dehydrogenase(FateDH),formaldehyde dehydrogenase(FaldDH)and alcohol dehydrogenase(ADH)coencapsulated in silica gel prepared by modified sol-gel process as catalysts,TEOS as precursor,NADH as an electron donor.The highest yield of methanol was up to 92.1% under 37℃,pH7.0 and 0.3Mpa. 相似文献
982.
The preparation of a disaccharide 2, Neu5Ac-alpha-(2-->5)Neu5Gc having a alpha-benzyl protecting group at the reducing end, by the coupling of the easily accessible building units 4 and 5 is described. Subsequent deprotection of the coupling adduct led to the isolation of the target compound 2 in high yield. 相似文献
983.
Hoong‐Kun Fun Qingli Hao Jiang Wu Xujie Yang Lude Lu Xin Wang Suchada Chantrapromma Ibrahim Abdul Razak Anwar Usman 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(2):m87-m88
In the structure of the title compound, [CuII(en)2][(EtO)2P(S)S]2 (en is ethylenediamine) or [Cu(C2H8N2)2](C4H10O2PS2)2, the Cu atom lies on a center of inversion and is coordinated in a slightly distorted square coordination geometry by four N atoms from two ethylenediamine molecules. The diethyl dithiophosphate moieties, (EtO)2P(S)S?, act as counter‐anions. 相似文献
984.
Capillary gel electrophoresis for DNA sequencing. Laser-induced fluorescence detection with the sheath flow cuvette 总被引:1,自引:0,他引:1
Capillary polyacrylamide gel electrophoresis separation of dideoxycytidine chain-terminated DNA fragments is reported. A post-column laser-induced fluorescence detector based on the sheath flow cuvette was used to minimize background signals due to light scatter from the gel and capillary. A preliminary mass detection limit of 10(-20) mol of fluorescein-labeled DNA fragments was obtained. The system was used to analyze an actual DNA sequencing sample. Theoretical plate counts of 2 x 10(6) were produced. Gel stability limits the performance of the current system. 相似文献
985.
Determination of phosphonoformic acid in human plasma and urine by high-performance liquid chromatography with electrochemical detection 总被引:2,自引:0,他引:2
M K Hassanzadeh F T Aweeka S Wu M A Jacobson J G Gambertoglio 《Journal of chromatography. A》1990,525(1):133-140
Trisodium phosphonoformate (foscarnet) is used in the treatment of cytomegalovirus infections in immunocompromised patients, such as bone marrow and renal transplant recipients, as well as patients with the acquired immune deficiency syndrome. A simple high-performance liquid chromatographic assay is described using an electrochemical detector. The method is accurate, precise and reproducible. Hydrochlorothiazide is used as the internal standard. This assay allows measurement of foscarnet in biological fluids at concentrations as low as 33 microM. This method is being used for the analysis of samples in clinical trials and is important in the evaluation of the pharmacokinetic disposition of the drug. 相似文献
986.
A practical speciation method for a solid mixture of nickel species applicable to atmospheric monitoring of Ni0, Ni2+ and NiOx is reported. This involves magnetic extraction of Ni0 to separate it from the water-soluble nickel salts and the insoluble oxides, followed by adsorptive stripping voltammetry to quantify the nickel in each fraction. The separation scheme was validated by using calibration standards and by simulating air-filter samples prepared with authentic nickel products. The recoveries of nickel were Ni0 94–105% and total nickel 95–102%. 相似文献
987.
Xiao Yan Wu Sanna JÄÄskelÄinen Wu-Yen Linko 《Applied biochemistry and biotechnology》1996,59(2):145-158
A commercialRhizomucor miehei lipase was purified by ammonium sulfate precipitation. Phenyl Sepharose 6 Fast Row hydrophobic interaction chromatography,
and DEAE Sepharose Fast Flow anion-exchange chromatography. The recovery of lipase activity was 32% with a 42-fold purification.
The molecular size of the purified enzyme was 31,600 Dalton and the pI 3.8. The enzyme was stable for at least 24 h within
a pH range of 7.0-10.0, and 96.8% of the enzyme activity remained when kept at 30‡C for 24 h. Further, about 10–30% of the
lipase activity was inhibited by K+, Li+, Ni+, Co2+, Zn2+, Mg2+, Sn2+, Cu2+, Ba2+, Ca2+, and Fe2+ ions and by SDS, but EDTA had no effect. Under the experimental conditions, the optimum temperature for the hydrolysis of
olive oil was 50‡C (pH 8.0), and for the synthesis of 1-butyl oleate, 37‡C. It was concluded that hydrolytic activity of lipase
alone is not a sufficient criterion for its synthetic potential. The optimal molar ratio of oleic acid and 1-butanol was 2:1
for 1-butyl oleate synthesis. The 1-butyl oleate yield was unaffected by purification of the enzyme after 12 h. 相似文献
988.
KaiKANG ChengYouKAN YiDU YuZhongLI DeShanLIU 《中国化学快报》2005,16(6):831-834
Soap-flee P(MMA-EA-MAA) particles with narrow size distribution were synthesized by seeded emulsion polymerization of methyl methacrylate (MMA), ethyl acrylate (EA) and methacrylic acid (MAA), and large voids inside the particles were generated by alkali posttreatment in the presence of 2-butanone. Results indicated that the size of void and theparticle volume were related with the amount of 2-butanone. The generation mechanism of voids was proposed. 相似文献
989.
Wei Wang Rongliang Wang Fan Wu Boshun Wan 《Reaction Kinetics and Catalysis Letters》2005,85(2):277-282
Summary A Ni-promoted ligand free palladium catalyst system for Suzuki coupling of aryl bromides has been developed in high efficiency under mild reaction conditions. It was obtained in situ by introducing NiCl2 to PdCl2/PVP using a parallel high-throughput screening technique. A wide range of aryl bromides bearing a variety of functional groups was evaluated. 相似文献
990.
Ultra-long single-crystalline trigonal selenium submicrotubes were synthesized using a facile one-step solution-phase approach with the assistance of nonionic surfactant Polyoxyethylene(20)sorbitan monolaurate (Tween-20), which turned out to be significant for the formation of ultra-long Se submicrotubes. XRD, Raman, SEM, and TEM were adopted to characterize the morphology, structure and phase composition of the as-prepared Se products. It was found that the length of the obtained Se submicrotubes was over 100 microm. By variation of the experimental parameters, the t-Se spheres, nanowires, and broken microtubes can be prepared. The possible growth mechanism of the ultra-long selenium submicrotubes was explained. In addition, we have also demonstrated that the synthesized ultra-long t-Se submicrotubes using the Tween-20-assisted approach can electrochemically charge and discharge with the high capacity of 265 mAh/g (corresponding to 0.97 wt % hydrogen in SWNTs) under normal atmosphere at room temperature. Cyclic voltammetry was adopted to investigate the adsorption-oxidation behavior of ultra-long selenium submicrotubes. It was observed that the morphology of the synthesized selenium products had a remarkable influence on their capacity of electrochemical hydrogen storage. These differences in hydrogen storage capacity are likely due to the size and density of tubes as well as the microcosmic morphology of different Se samples. The as-obtained ultra-long Se submicrotubes are expected to find wide applications in hydrogen storage, high-energy batteries, and optoelectronic, biologic, and catalytic fields as well as in the studies of structure-property relationships. This simple Tween-assisted approach might be extended to the preparations of one-dimensional nanostructures of tellurium and other anisotropic materials. 相似文献