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201.
Yuka MiyakeYu Kimura Syungo IshikawaHiroshi Tsujita Hiroki MiuraMichiko Narazaki Tetsuya MatsudaYasuhiko Tabata Tetsuya YanoAkio Toshimitsu Teruyuki Kondo 《Tetrahedron letters》2012,53(34):4580-4583
Novel chiral dendrimer-triamine-coordinated Gd complexes were synthesized and shown to have longitudinal relaxivity (r1) 3 times higher than that of clinically used Gd-DTPA. The pharmacokinetic differences between optical isomers were estimated from the affinity of 2-(R) and 2-(S) with bovine serum albumin (BSA), respectively, by a quartz crystal microbalance (QCM) measurement. As a result, the association constant Ka of 2-(S) was about 4 times higher than that of 2-(R), which means that 2-(S) is retained in the vascular retention for a longer time after administration. This result was also supported by T1-weighted MR images of mice before and after the intravenous injection of 2-(R) and 2-(S), as well as the time-course of the signal intensities (SI) at the blood vessels and quantification of Gd3+ concentration in the blood and urine. 相似文献
202.
Reduction kinetics of Pu(IV) by N,N-dimethylhydrazine (NNDMH) were studied by spectrophotometry, and the reduction rate equation
in 3M (mol/dm3) nitric acid was obtained. The reduction properties of NNDMH for U(VI), Np(VI), and Pu(IV) was studied in the mixture solution
of trin-butylphosphate diluted to 30 vol.% by n-dodecane (30% TBP) and 3M nitric acid. It was confirmed that NNDMH selectively
reduce Np(VI) to Np(V) without affecting the valences of U(VI) and Pu(IV) in a few minutes. Numerical simulation indicated
that 99.9% of Np was separated from U and Pu applying NNDMH for a mixer-settler. 相似文献
203.
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205.
Fabrication of nanorattles with passive shell 总被引:1,自引:0,他引:1
Chen HM Liu RS Asakura K Lee JF Jang LY Hu SF 《The journal of physical chemistry. B》2006,110(39):19162-19167
This investigation describes the formation of a metal nanorattle with a pure metal shell by varying experimental parameters. The galvanic replacement reaction between silver and chloroauric acid was adopted to prepare hollow metal nanoparticles. This approach is extended to produce nanorattles of Au cores and Au shells by starting with Au(core)Ag(shell) nanoparticles as templates. The effect of temperature on the nanostructure of the final product is also considered. The composition of the shell in nanorattles can be controlled by varying the reaction temperature (to form pure gold or gold-silver alloy, for example). X-ray absorption fine structure spectroscopy is conducted to elucidate the fine structure of these nanoparticles. Partial alloying between the Au core and the Ag shell is observed by extended X-ray absorption fine structure (EXAFS). 相似文献
206.
Donghui Guo Yuta Nakagawa Hiroko Ariga Shushi Suzuki Kumiko Kinoshita Takeshi Miyamoto Satoru Takakusagi Kiyotaka Asakura Shigeki Otani S.Ted Oyama 《Surface science》2010,604(17-18):1347-1352
The surface structure of Ni2P (101?0), a model for highly active hydrodesulfurization catalysts, was studied using scanning tunneling microscopy (STM) and low energy electron diffraction (LEED) in order to understand the reconstruction of the surface layers. Annealing at 573 K revealed a (1 × 1) LEED pattern which changed to a c(2 × 4) arrangement by further heating to 723 K. Atomic scale STM images were obtained for both the (1 × 1) and c(2 × 4) structures. Bright spots observed in the STM images were interpreted to be due to surface phosphorus atoms and this was supported by a density functional theory (DFT) simulation. Several possible models for the c(2 × 4) reconstructed structures were proposed including a P-dimer defect model, a missing-row model and a missing-row + added-row model. The last model gave the best explanation for the c(2 × 4)structure. The mechanism for the c(2 × 4) reconstruction on the Ni2P (101?0) surface is discussed. 相似文献
207.
Eiji Ihara Toshimitsu Hiraren Tomomichi Itoh Kenzo Inoue 《Journal of polymer science. Part A, Polymer chemistry》2008,46(5):1638-1648
Palladium‐mediated polymerization of cyclic diazoketones was investigated. Although cyclic diazoketones 1a,b derived from cyclohexanone and 1‐tetralone did not homopolymerize, they can be used as a comonomer for copolymerization with polymerizable acyclic diazoketones. On the other hand, an α,β‐unsaturated cyclic diazoketone 2a prepared from 2‐cyclohexen‐1‐one polymerized to give a polymer poly 2a ′ with Mn = 1400 in a 23.8% yield. Addition of some nucleophiles to C?C bond in poly 2a ′ was carried out. Copolymerization of 2a and its dimethyl‐substituted analogues 2b,c with acyclic diazoketones was also investigated. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1638–1648, 2008 相似文献
208.
Atsushi Asai Yoshiaki Mishina Toshimitsu Ogura Masaaki Omiya 《Journal of sound and vibration》2004,277(3):539-545
The Japanese Environmental Agency (now the Ministry of the Environment) updated the environmental quality standards for noise in April 1999. The new standards replaced the median value of percentile level L50 for noise evaluation with the equivalent sound pressure level LAeq. The standards renewed the classification of areas and time sections. The most significant change was the introduction of category of artery-road-adjacent area.This report sets the range of the artery-road-adjacent area to 20 m or less from the applicable road to compare the new standards with the old, based on data collected in Nagoya City. The achieved rates for the new standards seem to be on the whole the same as those for the old standards. However, a detailed analysis reveals some differences, such as higher achieved rates in the artery-road-adjacent areas and lower achieved rates in the general areas for the new standards than for the old. 相似文献
209.
Takaoki Ishii Ryo Watanabe Toshimitsu Moriya Prof. Dr. Hirohisa Ohmiya Prof. Dr. Seiji Mori Prof. Dr. Masaya Sawamura 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(40):13547-13553
Catalyst–substrate hydrogen bonds in artificial catalysts usually occur in aprotic solvents, but not in protic solvents, in contrast to enzymatic catalysis. We report a case in which ligand–substrate hydrogen‐bonding interactions cooperate with a transition‐metal center in alcoholic solvents for enantioselective catalysis. Copper(I) complexes with prolinol‐based hydroxy amino phosphane chiral ligands catalytically promoted the direct alkynylation of aldehydes with terminal alkynes in alcoholic solvents to afford nonracemic secondary propargylic alcohols with high enantioselectivities. Quantum‐mechanical calculations of enantiodiscriminating transition states show the occurrence of a nonclassical sp3‐C? H???O hydrogen bond as a secondary interaction between the ligand and substrate, which results in highly directional catalyst–substrate two‐point hydrogen bonding. 相似文献
210.
Toshimitsu Suzuki Shun-Ichi Izuka Shigeki Kondo Yoshinobu Takegami 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(3):633-642
The polymerization and catalytic behavior of a Ziegler type catalyst supported on poly(ethylene-co-vinyl alcohol) (EVA) were investigated. The rate of ethylene polymerization by a catalyst prepared from titanium tetrachloride supported on EVA (vinyl alcohol 18 mole %) and triethylaluminum (AlEt3) is much higher than that of an n-butoxytitanium trichloride (BTT)-AlEt3 catalyst. The polymer-supported catalyst has prolonged high activity during polymerization compared with the BTT-AlEt3 catalyst. The stabilization of the catalyst seems to depend on its slower reduction by alkylaluminum compounds, due to steric hindrance by bulky polymer ligands. Polypropylene prepared by the polymer supported Ziegler catalyst is essentially atactic, and it differs little from that prepared with a BTT-AlEt3 catalyst. Vinyl chloride was also polymerized by this catalyst. The catalytic activity was, however, very small. 相似文献