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871.
A synthetic strategy featuring efficient ruthenium-catalyzed asymmetric hydrogenation of racemic α-aryloxy cyclic ketone via dynamic kinetic resolution and palladium-catalyzed intramolecular reductive Heck cyclization has been developed for the asymmetric total synthesis of (-)-galanthamine (20.1%, 12 steps) and (-)-lycoramine (40.2%, 10 steps). 相似文献
872.
Li J Jiang G Yang B Dong X Feng L Lin S Chen F Ashraf M Jiang Y 《Analytical and bioanalytical chemistry》2012,402(3):1347-1354
Fusarium proliferatum was isolated as a major pathogen causing the Fusarium disease in harvested banana fruit. One of its major compounds, fusaric acid, was identified by high-performance liquid chromatography–electrospray
ionization mass spectrometry (HPLC–ESI–MS). Because the light intensity of the luminescent bacterium Vibrio qinghaiensis sp. Nov. Q67 can be inhibited by fusaric acid, the fusaric acid content of F. proliferatum was assessed and compared by both the HPLC and luminescent bacterium methods. Although both methods afforded almost similar
values of fusaric acid, the latter indicated slightly lower content than the former. Czapek medium was more suitable for the
growth of F. proliferatum and fusaric acid production than modified Richard medium, with an optimum pH of approximately 7.0. However, no significant
(P < 0.05) correlation was obtained between the fusaric acid production and growth of mycelia of F. proliferatum. The study suggests that the bioevaluation by use of the luminescent bacterium was effective in monitoring fusaric acid production
by F. proliferatum without expensive equipment. 相似文献
873.
Detect early stage lung cancer by a LAMP microfluidic chip system with a real-time fluorescent filter processor 总被引:1,自引:0,他引:1
TongZhou Wang Ye Zhang GuoLiang Huang Can Wang Lan Xie Li Ma ZhiYong Li XianBo Luo Hao Tian Qiang Li Xin Li ZhouYan Lv XiaoFan Bao 《中国科学:化学(英文版)》2012,55(4):508-514
This work presents a promising clinical molecular diagnostics for early stage lung cancer. This novel diagnostic method utilized the loop-mediated isothermal amplification (LAMP), microfluidic chips and a confocal optical detector with a non-linear fluorescent filter processor. An isothermal amplification based microfluidic chip for the early diagnostics of lung cancer was developed and a confocal optical detector was improved by a novel real-time fluorescent filter to sensitively monitor the DNA amplification procedure with high signal to noise ratio and fluorescence collecting ability. Experiment showed that a rapid diagnostic of lung cancer by detecting the existence of the CEA mRNA could be performed in only 5 μL of reaction assay in less than 45 min. While the traditional in-tube RT-PCR set consumed more than 25 μL of the assay and took more than 90 min. 相似文献
874.
Najat Aburas Aleksandar Loli? Nikola Stevanovi? Tatjana Tripkovi? Sne?ana Nikoli?-Mandi? Rada Bao?i? 《Journal of the Iranian Chemical Society》2012,9(6):859-864
This study describes the effects of the substituents on electrochemical behavior and antioxidant activity of the six tetradentate Schiff bases, containing ethane-1,2-diamine or propane-1,2-diamine as the amine part and pentane-2,4-dione and/or 1-phenylbutane-1,3-dione as ??-diketone, and corresponding copper(II) complexes. Cyclic voltammograms of these compounds were recorded in dimethylsulfoxide and 0.1?M sodium perchlorate as supporting electrolyte with glassy carbon as working electrode at different scan rates. The voltammograms of Schiff bases alone showed only one irreversible peak. Voltammograms recorded for complexes showed the presence of quasi-reversible processes taking place at the metal center and reversible process at the ligand part. Both steric and inductive effects of substituents and structure of imine bridge of Schiff base ligands as well as complexes were discussed. These effects appear relevant for the antioxidant activity. Antioxidant activity of the investigated compounds expressed as Trolox equivalent antioxidant capacity is also discussed. The electrochemical behavior showed a high correlation with the antioxidant activity for investigated compounds. 相似文献
875.
Helical mesoporous silica nanorods were prepared using cetyltrimethylamrnonium bromide and achiral alcohols as the co-structure-directing agents.They were characterized using field-emission scanning electron microscopy,transmission electron microscopy,nitrogen sorptions,and small angle X-ray diffraction.The length of the silica nanorods increases with increasing the length of the alcohols.When n-heptanol and n-octanol were used,helical mesoporous silica nanorods with lamellar mesopores on the surfaces were obtained. 相似文献
876.
An ion chromatography method has been proposed for the determination of three common inorganic anions(chloride,nitrate and sulfate) in anionic surfactants using a single pump system.The new system consists of an ion exclusion column,a concentrator column,and an anion exchange column connected in series via two 6-ports valves in a Dionex ICS-2000 ion chromatograph.The valves were switched several times for removing surfactants,concentrating and separating the three anions.The chromatographic conditions were optimized.Detection limits(S/N = 3) were in the range of 0.10-0.68μg/L.The relative standard deviations(RSDs) of peak area were less than 4.6%.The recoveries were in the range of 84.1-112.6%. 相似文献
877.
Bao Feng Han Qing Ming Shi Xian Feng Wang Jian Bo Liu bSheng Qiang Chun Long Yang 《中国化学快报》2012,23(9):1023-2026
Ten novel 5-substituted derivatives of 3-(l-hydroxyethylidene)pyrrolidine-2,4-dione were synthesized.The compounds were confirmed by IR,:H NMR,MS and elemental analysis.The bioassay indicated that these compounds showed noticeable herbicidal activities,and compounds 6f and 6j exhibited excellent inhibitory activities against the stalk of Echinochloa crusgalli,with EC50 values of 94.4 and 72.7 mg/L,respectively. 相似文献
878.
High-pressure impregnation, a new preparation method for sorbents to remove H2S from hot coal gas, is introduced in this paper. Semi-coke (SC) and ZnO is selected as the support and active component of sorbent, respectively. The sorbent preparation process includes high-pressure impregnation, filtration, ovendry and calcination. The aim of this research is to primarily study the effects of the impregnation pressure on physical properties and desulfurization ability of the sorbent. The desulfurization experiment was carried out in a fixed-bed reactor at 500°C and a simulated coal gas used in this work was composed of CO (33 vol%), H2 (39 vol%), H2S (300 ppm in volume), and N2 (balance). Experimental results show that the pore structure of the SC support can be improved effectively and ZnO active component can be uniformly dispersed on the support, with the small particle size of 10-500 nm. Sorbents prepared using high-pressure impregnation have better desulfurization capacity and their active components have higher utilization rate. P20-ZnSC sorbent, obtained by high-pressure impregnation at 20 atm, has the best desulfurization ability with a sulfur capacity of 7.54 g S/100g sorbent and a breakthrough time of 44 h. Its desulfurization precision and efficiency of removing H2S from the middle temperature gases can reach <1 ppm and >99.7%, respectively, before sorbent breakthrough. 相似文献
879.
Xia BY Ng WT Wu HB Wang X Lou XW 《Angewandte Chemie (International ed. in English)》2012,51(29):7213-7216
In it for the long haul: Clusters of Pt nanowires (3D Pt nanoassemblies, Pt?NA) serve as an electrocatalyst for low-temperature fuel cells. These Pt nanoassemblies exhibit remarkably high stability following thousands of voltage cycles and good catalytic activity, when compared with a commercial Pt?catalyst and 20?%?wt Pt?catalyst supported on carbon black (20?% Pt/CB). 相似文献
880.