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排序方式: 共有483条查询结果,搜索用时 31 毫秒
41.
Kenji Kitaoka Hiromitsu Kozuka Toshinobu Yoko 《Journal of the American Ceramic Society》1998,81(5):1189-1196
Lead lanthanum zirconate titanate (PLZT, (Pb,La)(Zr,-Ti)O3 ) ceramic fibers were prepared by the sol-gel method from a solution of lead acetate trihydrate, lanthanum isopropoxide, zirconium n -propoxide, and titanium isopropoxide that contained 2-methoxyethanol as the solvent. The sols obtained from the solution were concentrated at 156°-174°C for 2 h. Concentration at higher temperatures resulted in more-viscous sols of higher specific gravities. The concentration resulted in the formation of spinnable sols, which had viscosities >105 mPas and exhibited Newtonian flow properties. These spinnable sols were formed to be so stable that no change in viscosity and spinnability was observed for more than three months when stored in a sealed container at room temperature. Gel-to-ceramic fiber conversion was investigated by means of X-ray diffractometry, infrared spectroscopy, and thermal analysis. Single-phase perovskite PLZT ceramic fibers 5-200 μm in diameter and >20 cm in length were obtained. Scanning electron microscopy (SEM) observation and Brunauer-Emmett-Teller (BET) measurement showed that heat treatment of the fibers at a lower rate resulted in the formation of fibers of denser microstructure. Although the SEM image of the cross section of the fibers revealed a relatively dense microstructure and a laser beam could be transmitted through a fiber 6 mm in length, BET measurement of the fibers indicated that the fibers had more than a few percent of open porosities, and scattering of light was observed in the laser-beam guiding test. 相似文献
42.
Tomohito Hamazaki Shigeki Sawazaki Tetsuro Nagasawa Yoko Nagao Yuko Kanagawa Kazunaga Yazawa 《Lipids》1999,34(1):S33-S37
The purpose of the present research was to clarify the effect of docosahexaenoic acid (DHA) intake on behavior and plasma catecholamines (CA). In Study 1, 42 students took either DHA-rich oil capsules containing 1.5–1.8 g DHA/d or control oil capsules containing 97% soybean oil plus 3% of another fish oil for 3 mon in a double-blind fashion. They took a psychological test (PF Study) at the start and end of the study. This study started at the end of summer vacation and ended just before the final exams. In the control group, external aggression (aggression against others) in PF Study was significantly increased at the end of the study as compared with that measured at the start (+8.9%), whereas it was not significantly changed in the DHA group (?1.0%). In a similar double-blind study (Study 2), we measured external aggression under nonstressful conditions. External aggression slightly decreased in the control group, whereas there were no significant changes in the DHA group. In Study 3 with 14 students, plasma CA were measured at the start and end of capsule administration period of 2 mon. Subjects were under continuous stress of the final exams that lasted throughout the whole study period. The ratio of plasma epinephrine to norepinephrine concentrations was significantly increased in the DHA group (78%), whereas it stayed at the same level in the control group. In Study 4, mice were fed either DHA-deficient diet or -sufficient diet for 4 wk, and their rearing frequency (an anxiety index) was measured. In the DHA-sufficient group, the rearing frequency was significantly less than in the other group. These effects of DHA intake may be applied to people in an attempt to ameliorate stress-related diseases. 相似文献
43.
Hori Tetsuya; Moriyama Hideaki; Kawaguchi Jitsutaro; Hayashi-Iwasaki Yoko; Oshima Tairo; Tanaka Nobuo 《Protein engineering, design & selection : PEDS》2000,13(8):527-533
A temperature-jump (T-jump) time-resolved X-ray crystallographictechnique using the Laue method was developed to detect small,localized structural changes of proteins in crystals exposedto a temperature increase induced by laser irradiation. In achimeric protein between thermophilic and mesophilic 3-isopropylmalatedehydrogenases (2T2M6T), the initial structural change uponT-jump to a denaturing temperature (~90°C) was found tobe localized at a region which includes a ß-turn and aloop located between the two domains of the enzyme. A mutant,2T2M6T-E110P/S111G/S113E, having amino acid replacements inthis ß-turn region with the corresponding residues ofthe thermophilic enzyme, showed greater stability than the originalchimera (increase of Tm by ~10°C) and no T-jump-inducedstructural change in this region was detected by our method.These results indicate that thermal unfolding of the originalchimeric enzyme, 2T2M6T, is triggered in this ß-turn region. 相似文献
44.
Ishiwata H Abe Y Kubota H Kawasaki Y Takeda Y Maitani T Nishijima M Fukasawa Y 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2002,43(1):49-56
The mean concentrations and daily intake of four antifungal agents were estimated based on the results of an analysis of 7,005 samples of food obtained in official inspections by Japanese local governments in fiscal year 1998. The mean concentration of diphenyl was 0.0004% of the allowable limit, and those of imazalil, o-phenylphenol, and thiabendazole were 14.0%, 3.5%, and 5.7%, respectively. The daily intakes of these antifungal agents per person, estimated from their concentrations and the daily consumption of the foods, were 0.000326, 1.89, 11.5, and 23.3 micrograms, respectively, and assuming a body weight of 50 kg, the amounts of these antifungal agents consumed were 0.000013%, 0.15%, 0.12%, and 0.47% of the acceptable daily intake, respectively. These values are similar to the values obtained on the basis of the results of the official inspection in fiscal years 1994 and 1996, except that the amount of diphenyl is much lower (1/100). 相似文献
45.
Uematsu Y Ogimoto M Kabashima J Suzuki K Kaneko R Funayama K Haneishi N Yasuno T Ogino S 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2005,46(4):133-138
Migration from multi-layer laminated film pouches intended for retort foods was investigated through HPLC analysis with a fluorescence detector, and measurements of residue on evaporation, consumption of potassium permanganate and total organic carbon. HPLC analysis revealed that the levels of migrants in oil and the water which were heated in the pouches (121 degrees C, 30 min) were ten times of those in the corresponding official simulants under the official conditions; n-heptane (25 degrees C, 60 min), and water (95 degrees C, 30 min). Bisphenol A diglycidyl ether and related compounds were found in the oil and the water heated in the pouches, as well as in the simulants. These compounds were thought to have been present in the adhesive between the laminated films, and migrated through the food-contact film of the package. Consumption of potassium permanganate and residue on evaporation of the heated water were ten times of those of the water simulant, while the total organic carbon level of the heated water was several-hold greater than that of the water simulant. In addition, migrant levels per surface area of the pouch were one-fourth of the concentrations per content volume of the pouch. Since compliance with the legal limits is evaluated based on the concentration per surface area, real migration into foods would be underestimated by a factor of another four. 相似文献
46.
Ayako Sakai Yoko Yamakoshi Naoki Miyata 《Fullerenes, Nanotubes and Carbon Nanostructures》1999,7(5):743-756
Cell transformation in vitro is a model of carcinogenesis in vivo. Two-stage transformation assay increases the sensitivity of cells to chemicals and permits detection of carcinogens acting as initiating agents. [60]Fullerene (C60) was cytotoxic in BALB/3T3 cells when it was irradiated by visible light, but not without light irradiation. Under conditions when C60 was cytotoxic, it acted as an initiating agent for cell transformation, but it did not act as a complete transforming agent. the initiating activity of visible-light-irradiated C60 was statistically significant in a modified two-stage transformation assay including a procedure for replating cells treated by C60 and light, but it was equivocal in the standard two-stage transformation assay. 相似文献
47.
The effect of aluminium on the polymerization of silicic acid was studied at pH 7, 8 and 9 in the aluminium concentration range of 0–26 ppm (Al) by spectrophotometry, gel chromatography and 27Al NMR. Retarding and accelerating effects of aluminium on the growth of polysilicic acid particles and on the reaction between monosilicic acid and polysilicic acid were observed by changing the pH. It is suggested that the accelerating effect on the reaction between polysilicic acid particles is due to the formation of aluminium hydroxide on the surface of polysilicic acid. The rate of decrease in the monosilicic acid concentration in the presence of aluminium was faster than that in the absence of aluminium at pH 9, because monosilicic acid could be adsorbed rapidly on the aluminium hydroxide. From the results it was presumed that the formation of aluminium hydroxide on the solid surface may accelerate the deposition of silicic acid from geothermal water. 相似文献
48.
S. Shiroya A. Yamamoto K. Shin T. Ikeda S. Nakano H. Unesaki 《Progress in Nuclear Energy》2002,40(3-4):489-496
A basic study on the nuclear characteristics in the accelerator driven subcritical reactor (ADSR) was performed through a series of neutronics design calculations and reactor physics experiments. Calculations were executed mainly by the MCNPX code, and experiments were performed at the Kyoto University Critical Assembly (KUCA). Some nuclear features of the research reactor type ADSR were revealed through the present study. The following facts were found: 1) Further studies are necessary concerning the nuclear data in the high energy region and the generated neutrons through the spallation reactions especially by the light nuclei and the lower energy protons. 2) The adjustment of subcriticality by the control rod significantly affects the reactor power of ADSR because of the distortion in the neutron flux distribution caused by the control rod insertion. 3) An accurate calculation is essential to evaluate the neutron multiplication in the ADSR. 4) The neutronics behavior after a pulse injection can be approximately simulated by the calculation. 相似文献
49.
Hiroshi Numakura Tatsuru Watanabe Makoto Uchida Yoko Yamabe-Mitarai Eisuke Bannai 《Journal of Phase Equilibria and Diffusion》2006,27(6):638-643
The diffusion in iridium-rich Ir-Nb alloys has been studied by single-phase interdiffusion experiments. The chemical diffusion
coefficient has been measured for the primary fcc solid-solution and theL12 ordered compound Ir3Nb in the temperature range between 1650 and 1950 °C, using Ir/Ir-8Nb and Ir-26Nb/Ir-28Nb diffusion couples, respectively
(numbers indicate mol%). While the chemical diffusion coefficient in the solid-solution phase is close to the tracer self-diffusion
coefficient of pure iridium, the diffusion in the compound phase is extremely slow: the chemical diffusion coefficient is
1/40 to 1/50 of that in the solid solution. The low diffusion rate in the compound must be beneficial for high-temperature
performance of refractory superalloys based on the Ir-Nb system.
This article was presented at the Multicomponent-Multiphase Diffusion Symposium in Honor of Mysore A. Dayananda, which was
held during TMS 2006, 135th Annual Meeting and Exhibition, March 12–16, 2006, in San Antonio, TX. The symposium was organized
by Yongho Sohn of University of Central Florida, Carelyn E. Campbell of National Institute of Standards and Technology, Richard
D. Sisson, Jr., of Worcester Polytechnic Institute, and John E. Morral of Ohio State University. 相似文献
50.
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