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排序方式: 共有483条查询结果,搜索用时 15 毫秒
51.
Yuka Tarui Takumi Chinen Dr. Yoko Nagumo Dr. Takayuki Motoyama Dr. Toshiaki Hayashi Dr. Hiroshi Hirota Dr. Makoto Muroi Yasuyuki Ishii Hisae Kondo Prof. Dr. Hiroyuki Osada Prof. Dr. Takeo Usui 《Chembiochem : a European journal of chemical biology》2014,15(7):934-938
Terpendole E is first natural product found to inhibit mitotic kinesin Eg5, but its inhibitory mechanism remains to be revealed. Here, we report the effects of terpendole E and 11ketopaspaline (a new natural terpendole E analogue) on the Eg5–microtubule interaction and in several Eg5 mutants. 11‐Ketopaspaline is a shunt product from terpendole E, and it shows potent inhibitory activity against the microtubule‐stimulated ATPase activity of Eg5. Unlike other Eg5 inhibitors, such as S‐trityl‐L ‐cysteine (STLC) and GSK‐1, both terpendole E and 11‐ketopaspaline only partially inhibited Eg5–microtubule interaction. Furthermore, terpendole E and 11‐ketopaspaline inhibited several Eg5 mutants that are resistant to STLC (Eg5D130A, Eg5L214A) or GSK‐1 (Eg5I299F, Eg5A356T), but with the same extent of inhibition against wild‐type Eg5. Because Eg5D130A and Eg5L214A show cross‐resistance to most known Eg5 inhibitors, which bind the L5 loop, these results suggest that terpendole E and its analogues have a different binding site and/or inhibitory mechanism to those for L5 loop‐binding type Eg5 inhibitors. 相似文献
52.
Yoko Akutsu Kosuke Tanaka Masahiko Osaka 《Journal of Nuclear Science and Technology》2015,52(10):1281-1284
The effects of impurity Zr on dissolution behavior into nitric acid of sintered Mo pellets were investigated using simulated fuels to accumulate basic data and knowledge concerning the matrix of Mo-cermet fuels. Mo pellets containing 1– 10 mol% Zr were prepared by conventional powder metallurgical route. After characterization tests using optical microscopy (OM), X-ray diffraction and secondary electron microscopy-energy dispersive X-ray spectrometry (EDX), the sintered pellets were subjected to dissolution tests by nitric acid. The apparent dissolution rate of Mo pellets containing impurity Zr was found to be followed by the first-order chemical reaction form, which is generally known as a simple chemical reaction. The rate of dissolution of sintered Mo-cermet fuels by nitric acid was found to decrease with the increase of the amount of impurity Zr. 相似文献
53.
Zhuang Y Ahn S Seyfferth AL Masue-Slowey Y Fendorf S Luthy RG 《Environmental science & technology》2011,45(11):4896-4903
Nanoscale zerovalent iron particles (nZVI), bimetallic nanoparticles (nZVI/Pd), and nZVI/Pd impregnated activated carbon (nZVI/Pd-AC) composite particles were synthesized and investigated for their effectiveness to remove polybrominated diphenyl ethers (PBDEs) and/or polychlorinated biphenyls (PCBs). Palladization of nZVI promoted the dehalogenation kinetics for mono- to tri-BDEs and 2,3,4-trichlorobiphenyl (PCB 21). Compared to nZVI, the iron-normalized rate constants for nZVI/Pd were about 2-, 3-, and 4-orders of magnitude greater for tri-, di-, and mono-BDEs, respectively, with diphenyl ether as a main reaction product. The reaction kinetics and pathways suggest an H-atom transfer mechanism. The reaction pathways with nZVI/Pd favor preferential removal of para-halogens on PBDEs and PCBs. X-ray fluorescence mapping of nZVI/Pd-AC showed that Pd mainly deposits on the outer part of particles, while Fe was present throughout the activated carbon particles. While BDE 21 was sorbed onto activated carbon composites quickly, debromination was slower compared to reaction with freely dispersed nZVI/Pd. Our XPS and chemical data suggest about 7% of the total iron within the activated carbon was zerovalent, which shows the difficulty with in-situ synthesis of a significant fraction of zerovalent iron in the microporous material. Related factors that likely hinder the reaction with nZVI/Pd-AC are the heterogeneous distribution of nZVI and Pd on activated carbon and/or immobilization of hydrophobic organic contaminants at the adsorption sites thereby inhibiting contact with nZVI. 相似文献
54.
Gaoling Zhao Hiromitsu Kozuka Toshinobu Yoko 《Solar Energy Materials & Solar Cells》1997,46(3):219-231
Rose bengal-deposited TiO2 film electrodes bearing dispersed Ag or Au nanoparticles were prepared by the sol-gel method. The dye-induced visible region photoresponse of the electrodes decreased with increasing Ag content up to a mole ratio of Ag/TiO2 = 0.0207, while the UV photoresponse increased. On the other hand, the dye-induced visible region photoresponse decreased to a less extent by incorporation of a larger amount of Au particles of Au/TiO2 = 0.06, along with decreased UV photoresponse. The effects of the metal particles on the dye sensitization of the electrodes were discussed in terms of band edge fluctuation induced by the surface metal particles, Schottky barriers at TiO2/metal interfaces, and surface plasma resonance. 相似文献
55.
Most household fuels used in Asian countries are solid fuels such as coal and biomass (firewood, crop residue and animal dung). The particulate matter (PM), CO, NOx and SOx produced through the combustion of these fuels inside the residence for cooking and heating has an adverse impact on people's health. PM 2.5 in particular, consisting of particles with an aerodynamic diameter of 2.5 μm or less, penetrates deep into the lungs and causes respiratory system and circulatory system diseases and so on. As a result, the World Health Organization (WHO) established guideline values for this type of particulate matter in 2005. In this study, the authors focused on PM 2.5 and estimated indoor exposure concentrations for PM 2.5 in 15 Asian countries. For each environment used for cooking, eating, heating and illumination in which people are present temporarily (microenvironment), exposure concentrations were estimated for individual cohorts categorized according to sex, age and occupation status. To establish the residence time in each microenvironment for each of the cohorts, data from time use surveys conducted in individual countries were used. China had the highest estimate for average exposure concentration in microenvironment used for cooking at 427.5 μg/m3 , followed by Nepal, Laos and India at 285.2 μg/m3, 266.3 μg/m3 and 205.7 μg/m3 , respectively. The study found that, in each country, the PM2.5 exposure concentration was highest for children and unemployed women between the ages of 35 and 64. The study also found that the exposure concentration for individual cohorts in each country was greatly affected by people's use of time indoors. Because differences in individual daily life activities were reflected in the use of time and linked to an assessment of exposure to indoor air-polluting substances, the study enabled detailed assessment of the impact of exposure. 相似文献
56.
57.
Sae-Hoon Kim Toshinobu Yoko Sumio Sakka 《Journal of the American Ceramic Society》1993,76(10):2486-2490
A thin plate of TeO2 glass of 5.0 × 4.0 × 0.25 mm3 size, which was large enough for various optical measurements, was obtained by a rapid quenching method. The linear refractive index was measured as a function of wavelength from 486.1 to 1000 nm. The refractive index at 486.1 nm was as high as 2.239. The optical energy band gap was estimated as 3.37 eV from the optical absorption spectrum. The third-order nonlinear optical susceptibility, χ(3) , was determined by the third-harmonic generation (THG) method. The χ(3) value was as high as 1.4 × 10−12 esu, about 50 times as large as that of SiO2 glass. The results are discussed based on Lines' model in which an influence of cationic empty d -orbitals on the nonlinear properties was taken into account. 相似文献
58.
Preparation, Structure, and Properties of Thermally and Mechanically Improved Aluminum Titanate Ceramics Doped with Alkali Feldspar 总被引:3,自引:0,他引:3
Masahide Takahashi Masahiro Fukuda Masaaki Fukuda Hisato Fukuda Toshinobu Yoko 《Journal of the American Ceramic Society》2002,85(12):3025-3030
Aluminum titanate (AT) ceramic materials doped with alkali feldspar ((Na0.6 K0.4 )AlSi3 O8 ) have been prepared. These ceramics exhibited high sinterability, large resistance to thermal decomposition, and large flexure strength. The existence of liquid-phase feldspar at sintering temperatures promoted the formation of AT ceramics as the sintering agent. It was considered that silicon ions substituting for aluminum ions at the surface of AT crystal grains lowered the surface energy and hindered the diffusion of Ti4+ and Al3+ , giving rise to the large resistance to thermal decomposition. As a result, doping with alkali feldspar was found to effectively improve the mechanical and thermal properties of AT ceramics. 相似文献
59.
Eiichi Tamiya Yoko Sugiura Toshifumi Takeuchi Masayasu Suzuki Isao Karube Akitane Akiyama 《Sensors and actuators. B, Chemical》1993,10(3):179-184
An integrated ultra micro glutamate sensor has been constructed with a 7 μm diameter platinized carbon-fiber disk (PCD) electrode and a platinum thin-film (PTF) counter electrode fabricated on the glass capillary tube. By platinization, the electrode activity of the carbon fiber is improved. In order to obtain a stable response, a pulse potential is applied for hydrogen peroxide measurement. The PTF counter electrode shows good stability and can be used as a substitute for a silver-silver chloride electrode. Since the integrated PCD electrode shows good characteristics as a hydrogen peroxide sensor, glutamate oxidase is immobilized onto the tip of the PCD electrode to construct the ultra micro glutamate sensor. The sensor shows stable response to glutamate and a response time within 12 s. The calibration range for glutamate measurement is 50–800 μM. 相似文献
60.
Jisun Jin Toshinobu Yoko Fumiaki Miyaji Sumio Sakka Toshiharu Fukunaga Masakatsu Misawa 《Journal of the American Ceramic Society》1993,76(3):630-634
The local structure of a Na2 O─SiO2 oxide glass and a Na2 O─iO2 ─Si3 N4 oxynitride glass has been investigated by the pulsed neutron diffraction method. In the oxide glass, the first peak of radial distribution function (RDF) curves appeared at 0.1627 nm corresponding to Si─O boxh length. In the oxynitride glass, the first peak of the RDF curve was shifted to longer distances at 0.1650 nm due to the coexistence of Si─O and Si─N boxhs. The first peak in the RDF curve of the oxynitride glass was deconvoluted into two peaks whose positions are located at 0.1626 and 0.1709 nm. The one at 0.1626 nm is ascribed to Si─O boxhs and the other at 0.1709 nm to Si─N boxhs. The number of silicon atoms around a nitrogen was found to be 2.42, suggesting that not all of the nitrogen atoms are boxhed to three silicon atoms, but 58% twofold (─N─) and 42% threefold (>N─) nitrogens coexist in the present Na-Si-O-N oxynitride glass. The formation of twofold nitrogens may arise from the reaction between ≡Si─O− and ≡Si3 N groups. This model is compatible with the experimental observation that the density and Vickers hardness of oxynitride glasses increase with the nitrogen content. 相似文献