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61.
Yutaka Kagawa Yasuo Kogo Hiroshi Hatta 《Journal of the American Ceramic Society》1989,72(6):1092-1094
Thermal expansion behaviors of a Si3 N4 -whisker-reinforced sodaborosilicate glass matrix composite are studied. An abrupt increase of the coefficient of thermal expansion is observed and is attributed to formation of crystobalite in the sodaborosilicate glass matrix. This thermal expansion behavior is discussed with special reference to the phase transformation of the crystobalite. 相似文献
62.
Sakayu Shimizu Kengo Akimoto Yoshifumi Shinmen Hiroshi Kawashima Michihiro Sugano Hideaki Yamada 《Lipids》1991,26(7):512-516
Incubation with sesame oil increases the mycelial dihomo-γ-linolenic acid content of an arachidonic acid-producing fungus,Mortierella alpina, but decreases its arachidonic acid content [Shimizu, S., K. Akimoto, H. Kawashima, Y. Shinmen and H. Yamada (1989)J. Am. Oil Chem. Soc. 66, 237–241]. The factor causing these effects was isolated and identified to be (+)-sesamin. The results obtained in experiments
with both a cell-free extract of the fungus and with rat liver microsomes demonstrated that (+)-sesamin specifically inhibits
Δ5 desaturase at low concentrations, but does not inhibit Δ6, Δ9 and Δ12 desaturases. Kinetic analysis showed that (+)-sesamin
is a noncompetitive inhibitor (Ki for rat liver Δ5 desaturase, 155 μM). (+)-Sesamolin, (+)-sesaminol and (+)-episesamin, also inhibited only Δ5 desaturases
of the fungus and liver. These results demonstrate that (+)-sesamin and related lignan compounds present in sesame seeds or
its oil are specific inhibitors of Δ5 desaturase in polyunsaturated fatty acid biosynthesis in both microorganisms and animals.
On leave from Suntory Ltd. 相似文献
63.
Isao Mochida Yozo Korai Hiroshi Fujitsu Kenjiro Takeshita Yoshinobu Komatsubara Kei-Ichiro Koba Harry Marsh 《Fuel》1984,63(1):136-139
Cokes were prepared from nine coals of different rank and characterized by surface area measurement, reactivity to carbon dioxide at 1473K and Raman-laser spectroscopy. Rates of gasification of cokes on a unit surlface area basis (K1 = g m?2 min?1) decreased with increasing rank of parent coal based on maximum oil reflectances. However rates of gasification could not be related to coke structure as measured by Raman-laser spectroscopy. 相似文献
64.
Akio Takemura Yoshinori Shimizu Bunichiro Tomita Hiroshi Mizumachi 《The Journal of Adhesion》1992,37(1):161-172
Dynamic mechanical properties and adhesive strengths of power feed copolymer and random copolymer synthesized using styrene or methyl methacrylate and n-butyl acrylate were investigated. Although the two systems were synthesized from the same raw materials, power feed copolymer had a very broad transition compared with random copolymer. This fact was explained by the fact that the system synthesized through power feed method was an alloy of copolymers which are a continuous series from monomer A rich copolymers to monomer B rich copolymers. The dynamic mechanical behavior of film cast from solution was almost the same as that of emulsion film, which indicated more extensive application of power feed copolymer. In the P(nBA/St) system, power feed copolymer maintained its adhesive strengths over a wide temperature range compared with random copolymer. The absolute value, however, was not so high. This was due to the low cohesive strengths of the films. 相似文献
65.
Poly(p-tert-butoxycarbonyloxystyrene): a convenient precursor to p-hydroxystyrene resins 总被引:1,自引:0,他引:1
An efficient synthetic route to pure, high molecular weight poly(p-hydroxystyrene) is reported. The route involves synthesis of a new monomer, p-tert-butoxycarbonyloxystyrene, polymerization by radical initiation or by cationic initiation in liquid SO2, followed by thermolysis or acidolysis of the tert-butoxycarbonyl protecting group. Porous, crosslinked resin beads containing the nucleophilic, phenol pendant group have been prepared in a similar fashion from the precursor terpolymer of p-tert-butoxycarbonyloxystyrene, styrene and divinylbenzene. The utility of this resin for solid-phase synthesis has been demonstrated. 相似文献
66.
Hajime Miyama Kouichi Tanaka Yoshio Nosaka Nobuyuki Fujii Hiroshi Tanzawa Shoji Nagaoka 《应用聚合物科学杂志》1988,36(4):925-933
Polyacrylonitrile-g-poly(N,N-dimethylaminoethyl methacrylate) was synthesized photochemically and quaternized. The positively charged membranes made from the quaternized graftcopolymer showed high ultrafiltration rate for water by adding poly(vinyl alcohol) to casting solution and washing it out after the casting. In buffered saline solution, the permeability of the membranes was very small at pH below isoelectric point of albumin but increased markedly at higher pH. On the other hand, the permeability for γ-globulin was very small and did not show any pH dependence. 相似文献
67.
Arai Kazuhito; Hishida Atsushi; Ishiyama Mariko; Kamata Takeo; Uchikoba Hiroyuki; Fushinobu Shinya; Matsuzawa Hiroshi; Taguchi Hayao 《Protein engineering, design & selection : PEDS》2002,15(1):35-41
Lactobacillus casei allosteric L-lactate dehydrogenase (L-LDH)absolutely requires fructose 1,6-bisphosphate [Fru(1,6)P2] forits catalytic activity under neutral conditions, but exhibitsmarked catalytic activity in the absence of Fru(1,6)P2 underacidic conditions through the homotropic activation effect ofsubstrate pyruvate. In this enzyme, a single amino acid replacement,i.e. that of His205 conserved in the Fru(1,6)P2-binding siteof certain allosteric L-LDHs of lactic acid bacteria with Thr,did not induce a marked loss of the activation effect of Fru(1,6)P2or divalent metal ions, which are potent activators that improvethe activation function of Fru(1,6)P2 under neutral conditions.However, this replacement induced a great loss of the Fru(1,6)P2-independentactivation effect of pyruvate or pyruvate analogs under acidicconditions, consequently indicating an absolute Fru(1,6)P2 requirementfor the enzyme activity. The replacement also induced a significantreduction in the pH-dependent sensitivity of the enzyme to Fru(1,6)P2,through a slight decrease and increase of the Fru(1,6)P2 sensitivityunder acidic and neutral conditions, respectively, indicatingthat His205 is also largely involved in the pH-dependent sensitivityof L.casei L-LDH to Fru(1,6)P2. The role of His205 in the allostericregulation of the enzyme is discussed on the basis of the knowncrystal structures of L-LDHs. 相似文献
68.
Norikazu Nishiyama Tao Zheng Yusuke Yamane Yasuyuki Egashira Korekazu Ueyama 《Carbon》2005,43(2):269-274
Microporous carbons have been synthesized by the carbonization of cationic surfactant-resorcinol/formaldehyde (RF) composites, which were themselves formed by electrostatic organic-organic interaction. The porous structure produced by the decomposition of the surfactant plays an important role for the gasification of the RF polymer at higher temperatures. The pore size of the carbon prepared from tetrapropylammonium bromide (TPAB)-RF, cetyltrimethylammonium bromide (C16TAB)-RF and decyltrimethylammonium bromide (C10TAB)-RF mixtures can be estimated as 0.53 nm from the Horvath-Kawazoe method using N2 adsorption isotherms. Their pore size distributions were very narrow, showing that the microporous carbons derived from surfactant-RF mixture may have promise as adsorbents and membrane materials. 相似文献
69.
Yutaka Nagai Hiroshi Kondo Noriyuki Tatsumi 《Journal of Automated Methods and Management in Chemistry》2005,2005(4):235-239
Rapid and accurate analysis of platelet count plays an important role in evaluating hemorrhagic status. Therefore, we evaluated platelet counting performance of a hematology analyzer, Celltac F (MEK-8222, Nihon Kohden Corporation, Tokyo, Japan), that
features easy use with low reagent consumption and high throughput while occupying minimal space in the clinical laboratory. All blood samples were anticoagulated with dipotassium ethylenediaminetetraacetic acid (EDTA-2K). The samples were stored
at room temperature (18^C–22^C) and tested within 4 hours of phlebotomy. We evaluated the counting ability of the Celltac F hematology analyzer by comparing it with the platelet counts obtained by the flow cytometry method that ISLH and ICSH recommended, and also the manual visual method by Unopette (Becton Dickinson Vacutainer Systems). The ICSH/ISLH reference method is based on the fact that platelets can be stained with monoclonal antibodies to CD41 and/or CD61. The dilution ratio was optimized after the precision, coincidence events, and debris counts were confirmed by the reference method. Good correlation of platelet count between the Celltac F and the ICSH/ISLH reference method (r = 0.99, and the manual visual method (r= 0.93) were obtained. The regressions were y = 0.90 x+9.0 and y=1.11x+8.4, respectively. We conclude that the Celltac F hematology analyzer for platelet counting was well suited to the ICSH/ISLH reference method for rapidness and reliability. 相似文献
70.
Shimizu Sakayu Akimoto Kengo Kawashima Hiroshi Shinmen Yoshifumi Yamada Hideaki 《Journal of the American Oil Chemists' Society》1989,66(2):237-241
The mycelial dihomo-γ-linolenic acid content of an arachidonic acid-producing fungus,Mortierella alpina 1S-4, was found to increase, with an accompanying marked decrease in its arachidonic acid content, on cultivation with sesame
oil. The resultant mycelia were found to be a rich source of dihomo-γ-linolenic acid. This unique phenomenon was suggested
to be due to specific repression of the conversion of dihomo-γ-linolenic acid to arachidonic acid by the oil. After fractionation
of the oil with acetone into oil and non-oil fractions, it was found that the effective factor(s) was present in the non-oil
fraction. In a study on optimization of the culture conditions for the production of dihomo-γ-linolenic acid byM. alpina 1S-4, a medium containing glucose, yeast extract and the non-oil fraction was found to be suitable for the production. Under
the optimal conditions in a 50-1 fermentor, the fungus produced 107 mg of dihomo-γ-linolenic acid/g dry mycelia (2.17 g/l
of culture broth). This value accounted for 23.1% of the total fatty acids in the lipids extracted from the mycelia. The mycelia
were also rich in arachidonic acid (53.5 mg/g dry mycelia, 11.2%). Other major fatty acids in the lipids were palmitic acid
(24.1%), stearic acid (7.0), oleic acid (20.1), linoleic acid (6.6) and γ-linolenic acid (4.1).
On leave from Suntory Ltd. 相似文献