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871.
The cross-coupling of Grignard reagents with alkyl bromides and tosylates has been achieved by the use of eta(3)-allylnickel and eta(3)-allylpalladium complexes as catalysts. 相似文献
872.
Ohnuki H Saiki T Kusakari A Endo H Ichihara M Izumi M 《Langmuir : the ACS journal of surfaces and colloids》2007,23(8):4675-4681
Glucose oxidase (GOx) was immobilized in the organic-inorganic Langmuir-Bldogett (LB) films consisting of octadecyltrimethylammonium (ODTA) and nanosized Prussian blue (PB) clusters. The amperometric glucose biosensors based on the LB films were fabricated and tested. It was found that the sensors exhibited a clear response current under an applied voltage of 0.0 V (vs Ag/AgCl). The linearity of current density versus glucose concentration was confirmed below 15 mmol/L concentration. This is the first observation of biosensor function of the hybrid organic-inorganic LB films. The successful preparation of glucose sensors operating at the very low potential indicates that the adsorbed PB clusters in the LB films act as an electrocatalyst for the electrochemical reduction of hydrogen peroxide, which is the final product of the enzymatic reaction sequence. The observed low potential applicability is estimated to inhibit the responses of interferants such as ascorbic acid, uric acid, and acetominophen. It was also found that an electrostatic interaction between positively charged ODTA+ and the adsorbed species of both GOx and PB provided a stabilized adsorption state in the LB films. Such stable immobilization contributes to the steady amperometric response current observed in the present ODTA/PB/GOx LB films. 相似文献
873.
874.
Tsuneji Sano Hitoshi Hagimoto Jizhu Jin Yasunori Oumi Toshiya Uozumi Kazuo Soga 《Macromolecular rapid communications》2000,21(17):1191-1195
Inorganic siliceous porous materials such as MFI type zeolite, mesoporous silica MCM‐41 and silica gel with different average pore diameters were applied to the adsorptive separation of methylaluminoxane (MAO) used as a cocatalyst in α‐olefin polymerizations. The separated MAOs combined with rac‐ethylene‐(bisindenyl)zirconium dichloride (rac‐Et(Ind)2ZrCl2) were introduced to propylene polymerization, and their influences on the polymerization activity and stereoregularity of the resulting polymers were investigated. The polymerization activity and isotactic [mmmm] pentad of the produced propylene were markedly dependent upon the pore size of the porous material used for adsorptive separation. From the results obtained from solvent extraction of the produced polymers, it was suggested that there are at least two kinds of active species with different stereospecificity in the rac‐Et(Ind)2ZrCl2/MAO catalyst system. 相似文献
875.
Hitoshi Kumagai Katsuya Inoue 《Angewandte Chemie (International ed. in English)》1999,38(11):1601-1603
Below 5.4 K the one-dimensional polymeric complex made up of manganese(II ) hexafluoroacetylacetonate units and bridging bisaminooxylbenzene diradicals (shown in the picture) behaves as a metamagnet. The R-helical chain not only contains an S-configured chiral carbon center, but also an R-configured C2-symmetric chiral skeleton of the organic ligand. 相似文献
876.
Tomohiro Miyatake Hitoshi Tamiaki AlfredR. Holzwarth Kurt Schaffner 《Helvetica chimica acta》1999,82(6):797-810
Self-assembled aggregates of a synthetic zinc chlorin in an aqueous suspension with either α-lecithin or Triton X-100 exhibit unique structural and functional properties. Absorption, circular dichroism, fluorescence, and resonance Raman spectra indicate that the supramolecular structure in an aqueous microheterogeneous medium is very similar to that of the bacteriochlorophyll c aggregates in non-polar organic solvents and in chlorosomes, the main light-harvesting antennae of green photosynthetic bacteria. The nature of the aggregates is controlled by structure and/or concentration of the added surfactants. When a small amount of metal-free bacteriochlorin is present it acts as an efficient energy acceptor from the aggregated zinc chlorins. Thus, self-assembly of synthetic zinc chlorins, doped with appropriate energy acceptors and surrounded with surfactants, affords an artificial supramolecular light-harvesting device in aqueous environment. 相似文献
877.
Yuka Uchida Hsu Wen Huang Kazuyuki Horie Liu Yu Qing Hitoshi Tuchiya Junji Watanabe 《Journal of Polymer Science.Polymer Physics》2000,38(22):2922-2928
Using fluorescence spectroscopy, we investigated intermolecular interaction between mesogenic units in a thermotropic main‐chain LC polyester, P(HBA73/HNA27), containing oxybenzoate (HBA) and oxynaphthoate (HNA) mesogenic units. It is known that P(HBA73/HNA27), which has a high molecular weight, shows second harmonic generation (SHG) activity. P(HBA73/HNA27) showed fluorescence at 410 nm and 430 nm, originating from two kinds of intermolecular interaction. Fluorescence with a peak at 410 nm comes from the ground‐state complex between partially overlapping naphthoate units or between naphthoate and oxybenzoate units whose interaction is weak. Fluorescence at 430 nm comes from the ground‐state complex between fully overlapping naphthoate units whose interaction is strong. The relative fluorescence intensity for 430 nm compared to 410 nm increases with increases in inherent viscosity, ηinh, of P(HBA73/HNA27), the composition ratio of HNA/HBA, and temperature. The fluorescence intensity ratio, I430/I410, of P(HBA73/HNA27) shows the same inherent‐viscosity dependence with its sudden increase at ηinh = 1.4 ∽ 2.2 dL/g as its SHG activity does, supporting the polar structure and uniformity of LC orientation of the present LC polyester. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 2922–2928, 2000 相似文献
878.
Hitoshi Tanaka Tomomi Takeichi Takahiro Hongo 《Journal of polymer science. Part A, Polymer chemistry》1997,35(16):3537-3541
Radical homo- and copolymerizations of methyl α-trifluoroacetoxyacrylate (MTFAA) are studied by using azo initiators at 40 and 60°C. The rate of the homopolymerization of MTFAA was lower than that of methyl α-acetoxyacrylate. Monomer reactivity ratios (r), and Q and e values were estimated to be r1 = 0.03, r2 = 0.27, Q1 = 0.65, and e1 = 1.38 from the copolymerization of MTFAA (M1) and styrene (M2) at 60°C. Preferential crosspropagation was observed in particular in the copolymerization of MTFAA and α-methylstyrene. The influence of replacing the hydrogens of the acetoxy moiety of the acyloxyacrylate with the fluorines upon the copolymerization reactivity is discussed on the basis of the 13C-NMR chemical shift of various acyloxyacrylates. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 3537–3541, 1997 相似文献
879.
Kozo Matsumoto Hironobu Shimazu Masaki Deguchi Hitoshi Yamaoka 《Journal of polymer science. Part A, Polymer chemistry》1997,35(15):3207-3216
Anionic polymerizations of 1,1-dimethylsilacyclobutane, 1,1-diethylsilacyclobutane and 1-methyl-1-phenylsilacyclobutane were investigated. Addition of 5 mol % of butyllithium to a solution of 1,1-dimethylsilacyclobutane in THF-hexane (1 : 1) at −48°C provided poly(1,1-dimethylsilabutane) in 99% yield. Mn and Mw/Mn of the obtained polymer were 2400 and 1.10. This polymerization proceeded with a living nature. Mn increased in proportion as the yield of polymer increased. Addition of the second fresh feed of the monomer to the reaction mixture restarted polymerization of the second monomer at the same rate as in the initial stage. Addition of styrene to the living poly(1,1-dimethylsilabutane) provided a poly(1,1-dimethylsilabutane-b-styrene) block copolymer. It was also found that a polymerization of 1,1-diethylsilacyclobutane in THF-hexane at −48°C showed a living nature. In contrast, a polymerization of 1-methyl-1-phenylsilacyclobutane in THF at −78°C did not show a living nature. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3207–3216, 1997 相似文献
880.
Shinya MATSUSHIMA Yusuke KASAHARA Shun AIKAWA Takeru FUZIMURA Hitoshi YOKOYAMA Hironobu KATATA 《Physical Therapy Research》2021,24(3):285
Background: Early mobilization and rehabilitation interventions should be provided to patients who survived severe COVID-19 to improve their physical function and activities of daily living (ADL). However, their physical and mental status at discharge has not been well described in Japan. We report the intervention provided for a survivor of severe COVID-19 and his physical and mental status at discharge from an acute care hospital. Case Report: A 62-year-old man was admitted to our emergency department with a diagnosis of COVID-19 with severe acute respiratory dysfunction. He had complicated intensive care unit-acquired weakness (ICU-AW) and delirium during mechanical ventilation therapy. Rehabilitation intervention was initiated on the seventh day post-admission and was gradually performed according to his respiratory and hemodynamic status. As a result of the rehabilitation intervention, ICU-AW and cognitive function gradually improved. On hospital day 37, he independently performed basic ADL and was discharged. However, he lost approximately 9% of his body weight at discharge. In addition, his hand grip strength and six-minute walking distance were lower and shorter than the reference values, respectively. His mental component summary of the Short Form-8™ was lower than the national standard deviation for the Japanese population. Conclusion: Although survivors of severe COVID-19 who undergo early rehabilitation can be discharged from an acute care hospital, they may have several impairments in their physical and mental status, including muscle function, diffusion capacity, exercise tolerance, and health-related quality of life. 相似文献