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排序方式: 共有775条查询结果,搜索用时 15 毫秒
1.
Mitsuo Miyazawa Hideki Kawazoe Mitsuro Hyakumachi 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2003,78(6):620-625
The microbial transformation of l‐menthol ( 1 ) was investigated by using 12 isolates of soil‐borne plant pathogenic fungi, Rhizoctonia solani (AG‐1‐IA Rs24, Joichi‐2, RRG97‐1; AG‐1‐IB TR22, R147, 110.4; AG‐1‐IC F‐1, F‐4, P‐1; AG‐1‐ID RCP‐1, RCP‐3, and RCP‐7) as a biocatalyst. Rhizoctonia solani F‐1, F‐4 and P‐1 showed 89.7–99.9% yields of converted product from 1 , RCP‐1, RCP‐3, and RCP‐7 26.0–26.9% and the other isolates 0.1–12.0%. In the cases of F‐1, F‐4 and P‐1, substrate 1 was converted to (?)‐(1S,3R,4S,6S)‐6‐hydroxymenthol ( 2 ), (?)‐(1S,3R,4S)‐1‐hydroxymenthol ( 3 ) and (+)‐(1S,3R,4R,6S)‐6,8‐dihydroxymenthol ( 4 ), which was a new compound. Substrate 1 was converted to 2 and/or 3 by RRG97‐1, 110.4, RCP‐1, RCP‐3 and RCP‐7. The structures of the metabolic products were elucidated on the basis of their spectral data. In addition, metabolic pathways of the biotransformation of 1 by Rhizoctonia solani are discussed. Finally, from the main component analysis and the differences in the yields of converted product from 1 , the 12 isolates of Rhizoctonia solani were divided into three groups based on an analysis of the metabolites. Copyright © 2003 Society of Chemical Industry 相似文献
2.
Phase behavior in liquid crystallization was studied for a series of liquid crystalline (LC) diblock copolymers consisting of rubbery amorphous and side-chain liquid crystalline components, poly(n-butyl acrylate) (PBA) and poly[11-(4′-cyanophenyl-4″-phenoxy)undecyl acrylate] (PLC), respectively, using a time-resolved small-angle X-ray scattering (SAXS) techniques, DSC and polarized optical microscopy (POM). The block copolymers used had three kinds of copolymer compositions, 44, 20 and 15 wt% of PLC compositions (BLC44, BLC20 and BLC15, respectively). BLC44 showed a smectic liquid crystalline structure. In the process of liquid crystallization for BLC44, the SAXS peak due to the microphase separation structure existing before liquid crystallization was changed continuously to be at a smaller angular side, and at almost the same time, a new peak appeared at a further smaller angular side and developed. The former peak disappeared with the development of liquid crystallization. The behavior of these SAXS peaks suggests that the microphase separation structure was changed discretely at the transition from isotropic to smectic and that two phases coexist in the early stage of the liquid crystallization. The coexistence of two peaks in the early stage of the liquid crystallization corresponded to the POM observation. In the isotropization process, coexistence of two phases was not observed. For BLC20 exhibiting a cylindrical structure in both isotropic and liquid crystalline states, the liquid crystalline structure was not smectic but probably nematic, and the spacing was changed continuously in liquid crystallization. No liquid crystallization was observed in SAXS, POM and DSC for BLC15. The orientation of smectic layers within lamellar domains was investigated using 2D-SAXS images. The smectic layer was aligned perpendicularly to the lamellar interface. 相似文献
3.
4.
Mitsuo Miyazawa Tomohiko Takahashi Kazuki Sakata Isao Horibe 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2008,83(7):1006-1011
BACKGROUND: The biotransformation of sesquiterpenoids, which are a large class of naturally occurring compounds, using microorganisms as a biocatalyst to produce useful novel organic compounds was investigated. The biotransformation of sesquiterpenoids, (+)‐aromadendrene ( 1 ), (−)‐alloaromadendrene ( 2 ) and (+)‐ledene ( 3 ) has been investigated using Aspergillus wentii as a biocatalyst. Results: Compound 1 was converted to (−)‐(10S,11S)‐10,13,14‐trihydroxyaromadendrane ( 4 ). Compound 2 was converted to (+)‐(1S,11S)‐1,13‐dihydroxyaromadendrene ( 5 ) and (−)‐5,11‐epoxycadin‐1(10)‐en‐14‐ol ( 6 ). Compound 3 was converted to compound 6 , (+)‐(10R,11S)‐10,13‐dihydroxyaromadendr‐1‐ene ( 7 ) and (+)‐(10S,11S)‐10,13‐dihydroxyaromadendr‐1‐ene ( 8 ). The structure of the metabolic products has been elucidated on the basis of their spectral data. CONCLUSION: Compound 1 gave only one product that was hydroxylated at C‐10, C‐13 and C‐14. By contrast, compounds 2 and 3 gave a number of products, one of which was common. The differences in oxidation of 1–3 are due to the configuration of the C‐1 position. Compounds 4–8 were new compounds. Copyright © 2008 Society of Chemical Industry 相似文献
5.
Summary Cationic polymerization of p-methoxystyrene initiated by HI/ZnI2 in toluene afforded living polymers not only at low temperature (–15°C) but at room temperature (+25°C) as well. The number-average molecular weight of the polymers was directly proportional to monomer conversion and in excellent agreement with the calculated value assuming that one polymer chain forms per unit hydrogen iodide. On addition of a fresh feed of monomer at the end of the first-stage polymerization, the added feed was smoothly polymerized at nearly the same rate as in the first stage; the polymer molecular weight further increased in direct proportion to monomer conversion and was close to the calculated value for living polymer. Throughout these reactions, the molecular weight distribution of the polymers stayed very narrow (¯Mw/¯Mn<1.1). This is the first example of living cationic polymerizations of styrene derivatives that proceed even at room temperature. 相似文献
6.
Upper and lower critical solution temperatures have been determined for solutions of poly(ethylene glycol) in t-butyl acetate and water over the molecular weight range of Mη = 2.18 × 103 to ~1020 × 103. The phase diagram for solutions of poly(ethylene glycol) (Mη = 719 × 103) in t-butyl acetate was expressed as the ‘hour glass’ type, while the phase diagram for solution of poly(ethylene glycol) (Mη = 2.18 × 103 to ~2.29 × 103) in water was expressed as the ‘closed loop’ type. The value of the pressure dependence of the lower critical solution temperature in the poly(ethylene glycol) (Mη = 1020 × 103)/water system over the pressure range of 0 to ~50 atm was negligibly small and positive. 相似文献
7.
Summary The first example of the living cationic polymerization of isobutyl vinyl ether via the phosphate counteranion has been achieved in toluene below 0°C with a new initiating system that consists of diphenyl phosphate and zinc iodide, (C6H50)2P(0)0H/ZnI2. The number-average molecular weight of the polymers increased in direct proportion to monomer conversion, and was in excellent agreement with the calculated value assuming that one polymer chain forms per unit diphenyl phosphate. On addition of a fresh feed of monomer at the end of the polymerization, the added feed was smoothly polymerized at nearly the same rate as in the first stage, and the polymer molecular weight further increased in direct proportion to monomer conversion. Throughout the reaction, the molecular weight distribution of the polymers stayed very narrow (¯M/¯Mn 1.1). At room temperature (+25 °C), however, the molecular weight distribution of the polymers slightly broadened (¯Mw/¯Mn 1.2) at high conversions where the polymer molecular weight became smaller than the calculated value. Evidently, the (C6H50)2-P(0)0H/ZnI2 system indeed generates a propagating species of a long life-time at room temperature, but the perfectly living polymerization by this system operates below 0°C.Living cationic polymerization of vinyl ethers by electrophile 相似文献
8.
Minoru Tsuda Setsuko Oikawa Akira Yokota Mitsuo Yabuta Wataru Kanai Ken-Ichi Kashiwagi Isamu Hijikata Hisashi Nakane 《Polymer Engineering and Science》1983,23(18):993-999
A dry developable negative working resist composition comprised of poly(methyl isopropenyl ketone) (PMIPK) and 4-methyl-2,6-di(4′-azido-benzylidene) cyclohexanone-1 was examined. The main photochemical product formed in the resist pattern was found to be a secondary amine which crosslinks PMIPK. Post-annealing forms a hydrogen-bonded product which shows a powerful electronic excitation energy quenching effect. The quencher is more powerful than the aromatic compound arising from the azide by post-annealing only. The residual resist thickness of the negative pattern is about 80 percent of the initial thickness of the coating in spite of all the azide compound remaining in the resist coating. The obtained dry developed resist pattern has a high dry etch resistance. Etchings of Si and SiO2 were performed by plasma and reactive ion etching, respectively. 相似文献
9.
10.
Lin Lin Mitsuo Gen 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2009,13(2):157-168
Genetic Algorithms (GAs) and other Evolutionary Algorithms (EAs), as powerful and broadly applicable stochastic search and
optimization techniques have been successfully applied in the area of management science, operations research and industrial
engineering. In the past few years, researchers gave lots of great idea for improvement of evolutionary algorithms, which
include population initialization, individual selection, evolution, parameter setting, hybrid approach with conventional heuristics
etc. However, though lots of different versions of evolutionary computations have been created, all of them have turned most
of its attention to the development of search abilities of approaches. In this paper, for improving the search ability, we
focus on how to take a balance between exploration and exploitation of the search space. It is also very difficult to solve
problem, because the balance between exploration and exploitation is depending on the characteristic of different problems.
The balance also should be changed dynamically depend on the status of evolution process. Purpose of this paper is the design
of an effective approach which it can correspond to most optimization problems. In this paper, we propose an auto-tuning strategy
by using fuzzy logic control. The main idea is adaptively regulation for taking the balance among the stochastic search and
local search probabilities based on the change of the average fitness of parents and offspring which is occurred at each generation.
In addition, numerical analyses of different type optimization problems show that the proposed approach has higher search
capability that improve quality of solution and enhanced rate of convergence. 相似文献