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151.
Ohne Zusammenfassung 相似文献
152.
Saga Y Wazawa T Mizoguchi T Ishii Y Yanagida T Tamiaki H 《Photochemistry and photobiology》2002,75(4):433-436
The fluorescence emission properties of single chlorosomes from the green sulfur photosynthetic bacterium Chlorobium (Chl.) tepidum are studied for the first time, using a total internal reflection fluorescence microscope. The fluorescence peak positions of bacteriochlorophyll (BChl)-c self-aggregates in a single chlorosome of Chl. tepidum were widely distributed in the wavelength region between 750 and 768 nm, and the standard deviation (s.d. = 4.1 nm, n = 51) was larger than that of single chlorosomes of Chloroflexus (Cfl.) (s.d. = 1.9 nm, n = 50). The spectral heterogeneity among single chlorosomes from Chl. tepidum was in sharp contrast to those from Cfl. aurantiacus. The difference of chlorosomal spectral properties between Chl. tepidum and Cfl. aurantiacus at the single-unit level would be ascribed to the homolog composition of BChl-c--chlorosomes of Chl. tepidum have BChl substituted with various alkyl groups at both the 8- and 12-positions, whereas light-harvesting BChl-c molecules in Cfl. chlorosomes have the same substituents at the 8- (ethyl group) and 12- (methyl group) positions. 相似文献
153.
Celina M. H. de Figueiredo Sulamita Klein Yoshiharu Kohayakawa Bruce A. Reed 《Journal of Algorithms in Cognition, Informatics and Logic》2000,37(2):505
A skew partition as defined by Chvátal is a partition of the vertex set of a graph into four nonempty parts A, B, C, D such that there are all possible edges between A and B and no edges between C and D. We present a polynomial-time algorithm for testing whether a graph admits a skew partition. Our algorithm solves the more general list skew partition problem, where the input contains, for each vertex, a list containing some of the labels A, B, C, D of the four parts. Our polynomial-time algorithm settles the complexity of the original partition problem proposed by Chvátal in 1985 and answers a recent question of Feder, Hell, Klein, and Motwani. 相似文献
154.
Yasumasa Nishiwaki Kazunari Masutani Yoshiharu Kimura Chan-Woo Lee 《Journal of polymer science. Part A, Polymer chemistry》2020,58(6):860-871
Bis-hydroxyl-terminated poly(1,2-propylene succinate) (PPS-diols) with high molecular weight (10–40 kDa) are prepared by two-step melt polycondensation of succinic acid and 1,2-propanediol with Ti(BuO)4 as the catalyst. By using these PPS-diols as macroinitiators, the ring-opening polymerization of d - and l -lactides is readily conducted to obtain enantiomeric ABA triblock copolymers consisting of poly(l -lactide) and PPS (B) (t-l -PPS) as well as those of poly(d -lactide) and PPS (B) (t-d -PPS) which have higher PPS compositions (20–70 wt%) in addition to high molecular weight (20–80 kD). The Tg, Tm, and ΔHm values of the t-l -PPS copolymers as well as the stereo mixtures of t-l -PPS/t-d -PPS are controlled to linearly decrease with increasing the PPS content. The copolymers also exhibit higher elastomeric properties with increasing the PPS content. The tensile properties of the copolymer films having higher PPS contents (both the single block copolymers and stereo mixtures) are comparable to those of the oil-based thermoplastic elastomers. It is therefore concluded that these block copolymers can afford thermoplastic elastomers or flexible plastic materials having a 100% biobased content. 相似文献
155.
156.
Chan Woo Lee Shohei Nakamura Yoshiharu Kimura 《Journal of polymer science. Part A, Polymer chemistry》2012,50(6):1111-1119
Graft copolymers of poly(tulipalin A) (PT) and poly(DL‐lactide) (PDLLA) (PT‐g‐PDLLA) having various graft lengths and ratios were synthesized by free‐radical copolymerization of α‐methylene‐γ‐butyrolactone (MBL) and PDLLA macromonomers (HEMA‐PDLLA) terminated by 2‐hydroxyethyl methacrylate (HEMA)‐terminated. HEMA‐PDLLA were synthesized by ring opening polymerization (ROP) of DL‐lactide in the presence of HEMA. Both HEMA‐PDLLA and the copolymers were characterized by NMR spectroscopy and gel permeation chromatography (GPC). The thermal properties of the graft copolymers were found to depend on the graft length and the ratio. The copolymers consisting of PDLLA side chains of Mn = 500 Da showed a single Tg between Tgs of the two component polymers, suggesting a miscible state of PT and PDLLA. In contrast, the copolymers consisting of PDLLA side chains of Mn = 1100, 2000, and 7000 Da showed two isolated Tg, suggesting two segregated domains. The AFM phase images of the copolymers supported the single and phase‐separated morphologies for the former and latter systems, respectively. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
157.
Nicotine is the primary psychoactive component in tobacco. It is taken into the body by tobacco smoking, and mainly metabolized to cotinine in the hepatic cytochrme P450 (CYP) 2A6. The objective of this study was to develop a sensitive method for the determination of nicotine metabolism to cotinine using HPLC. The internal standard, trans-4'-carboxycotinine methyl ester was synthesized with a simple method. The nicotine and cotinine were separated completely and detected by C(18) 5-μm analytical column (L-column Octa decyl silyl (ODS), 150 mm × 4.6 mm i.d.) equipped with a C(18) 5-μm guard column (L-column ODS, 10 mm × 4.6 mm i.d.) and ultraviolet detection at 260 nm. The detection limit of the assay was 0.05 μM for cotinine (n=5, R.S.D) and 0.1 μM for nicotine. Thus the present results provided a sensitive and useful method for the determination of nicotine metabolism catalyzed by CYP2A6. 相似文献
158.
Yuichiro Haramoto Yoshiharu Kusakabe Masato Nanasawa Seiji Ujiie Stephan Mang Stephen C. Moratti 《Liquid crystals》2013,40(2):263-267
New 1,3-dioxane type ionic liquid crystal materials having a terminal double bond were synthesized. The mesomorphic behaviour of these compounds was measured. The principal features of these compounds are a smectic A phase over a very wide range including room temperature, and a low isotropic to mesophase transition temperature (for example, compound 6-1: Cr-22 SmA 25 I). 相似文献
159.
Shigeyoshi Nishino Yasuhiro Nagato Hisanao Yamamoto Yoshiharu Ishido 《Journal of carbohydrate chemistry》2013,32(2):199-213
Introduction of the triisopropylsilyl protecting group to the 3′-position of 5′-O-aroyl-2′-deoxyribonucleosides wa effectively performed by the use of triisopropylsilyl chlor ide in DMF in the presence of pyridine and lead(II) nitrate the latter was substituted in this reaction for silver nitr ate. Simple treatment of the resulting triisopropylsilyl ethers with sodium methoxide in THF gave 2′-deoxy-3′-O-tri-isopropylsilylribonucleosides in excellent yields. 相似文献
160.
Benjamin Briois Tsuguyuki Saito Christian Pétrier Jean-Luc Putaux Yoshiharu Nishiyama Laurent Heux Sonia Molina-Boisseau 《Cellulose (London, England)》2013,20(2):597-603
Aqueous suspensions of dispersed Glaucocystis cellulose microfibrils were sonicated at 4 °C for 3 h, using 24 kHz ultrasonic waves. This treatment induced a variety of ultrastructural defects, as the microfibrils became not only shortened, but also presented substantial damage materialized by kinks and subfibrillation. Upon analysis by X-ray diffraction and 13C solid-state NMR spectroscopy, it was found that the initial sample that contained 90 % of cellulose Iα allomorph became, to a large extent, unexpectedly converted into the Iβ phase, while the loss of crystallinity was only moderate during the sonication treatment. 相似文献