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91.
Takeo Taguchi Tomoyuki Takigawa Yumiko Tawara Tsutomu Morikawa Yoshiro Kobayashi 《Tetrahedron letters》1984,25(49):5689-5692
β-Fluoroallyl alcohols () were obtained with high stereoselectivity by the LiA1H4 reduction of 1-acetoxy-3-alkyl-2,2-difluorocyclopropanes (). 相似文献
92.
张玉虎 M.Oshima T.Morikawa T.Hayakawa Y.Toh 周小红 何建军 刘忠 甘再国 T.Shizuma M.Koizumi A.Osa J.Katakura Y.Hatsukawa M.Matsuda N.Shinohara T.Ishii H.Kusakari M.Sugawara K.Furuno T.Komatsubara T.Une 温书贤 竺礼华 王治民 许甫荣 《中国物理 C》2003,(4)
利用重离子熔合蒸发反应和在束γ谱学实验方法研究了双奇核176,178Ir和182 Au的高自旋态结构 ,在这 3个双奇核中观测到了基于πi13 2 νi13 2 准粒子组态下的转动带 .以能级间隔系统学为判据 ,对184Au核中πi13 2 νi13 2 转动带能级自旋进行了指定 .指出176,178Ir和182 ,184Au 4个双奇核的πi13 2 νi13 2 转动带在低自旋区均出现旋称反转 .对πi13 2 νi13 2 转动带旋称反转现象进行了定性的讨论 .用推转壳模型对πh9 2 νi13 2 带和πi13 2 νi13 2 带能级结构进行了理论研究 ,发现当采用形变和对力自洽计算后 ,从理论上可以定性地解释两个半退耦带出现的旋称反转现象 相似文献
93.
Roongsawang N Hase Ki Haruki M Imanaka T Morikawa M Kanaya S 《Chemistry & biology》2003,10(9):869-880
Arthrofactin is a potent cyclic lipopeptide-type biosurfactant produced by Pseudomonas sp. MIS38. In this work, an arthrofactin synthetase gene cluster (arf) spanning 38.7 kb was cloned and characterized. Three genes termed arfA, arfB, and arfC encode ArfA, ArfB, and ArfC, containing two, four, and five functional modules, respectively. Each module bears condensation, adenylation, and thiolation domains, like other nonribosomal peptide synthetases. However, unlike most of them, none of the 11 modules possess the epimerization domain responsible for the conversion of amino acid residues from L to D form. Possible L- and D-Leu adenylation domains specifically recognized only L-Leu. Moreover, two thioesterase domains are tandemly located at the C-terminal end of ArfC. These results suggest that ArfA, ArfB, and ArfC assemble to form a unique structure. Gene disruption of arfB impaired arthrofactin production, reduced swarming activity, and enhanced biofilm formation. 相似文献
94.
95.
M Hagiwara E Ohuchi K Hongo M Oki M Nakano M Amemiya T Morikawa K Kobashi 《Chemical & pharmaceutical bulletin》1990,38(5):1369-1372
The pharmacological activities of synthetic human CCK-33, in which a tyrosine molecule was sulfated by arylsulfotransferase, were investigated in the rat and the guinea-pig. The activities were compared with those of non-sulfated CCK-33 (CCK-33NS), CCK-8 and CCK-4. CCK-33 was about 100 fold more potent than non-sulfated CCK-33(CCK-33NS) but was about 20 fold less potent than CCK-8 in the contraction of the isolated gallbladder of the guinea-pig. In rat pancreatic secretion, intravenous CCK-33 and CCK-8 showed almost the same activity. The potency of each was about 1000 fold more than the individual potency of CCK-33NS, non-sulfated CCK-8 (CCK-8NS) and CCK4. There were no significant differences in gastric acid stimulatory activities among CCK-33, CCK-8, CCK-4, but the activities of CCK-33NS and CCK-8NS were less than those of CCK-33 and CCK-8, respectively. CCK-33 and CCK-8 produced a reduction in the intake of powder chow in doses of 10(-8) and 3 x 10(-8) mol/kg i.p., but CCK-33NS, CCK-8NS and CCK-4 did not. In conclusion, the activities of synthetic human CCK-33 are almost the same as those of CCK-8 on exocrine pancreatic secretion, gastric acid secretion and food intake, but less than CCK-8 on isolated gallbladder contraction. 相似文献
96.
Kazuya Morikawa Ryosuke L Ohniwa Joongbaek Kim Sayaka L Takeshita Atsushi Maruyama Yumiko Inose Kunio Takeyasu Toshiko Ohta 《Microscopy and microanalysis》2007,13(1):30-35
The nucleoid structure of an important human pathogen, Staphylococcus aureus, was dissected by atomic force microscopy (AFM). The nucleoids dispersed on a cover glass consisted of fibrous units with two different widths of 40 and 80 nm, a feature shared with those of Escherichia coli. On the other hand, cells exposed to an oxidative stress exhibited clogged nucleoids. A knock-out of mrgA (metallo regulated genes A) encoding a staphylococcal homolog of the nucleoid compaction factor (E. coli Dps) eliminated the compaction response to the oxidative stress and reduced the susceptibilities to H2O2 and UV irradiation. We also observed that the negative supercoiling of plasmids is increased by the oxidative stress. A possible interrelation between the helical density and the nucleoid compaction is discussed in relation to the oxidative stress response. 相似文献
97.
Morikawa T Narita S Klein DJ 《Journal of chemical information and computer sciences》2004,44(6):1891-1896
This article first revises graph-theoretical (local aromaticity and overall molecular) indices, introduced by M. Randi? in 1975, for benzenoid hydrocarbons and somewhat improves them for computer enumeration. This goes beyond total Kekulé structure enumeration, yielding an index calculation useful for the quantitative estimation of localization of different Kekuléan substructures (including ethylene-, benzene-, annulene-, and radialene-units). This may be viewed as a "molecules-in molecule" approach to polycyclic aromatic hydrocarbons within the context of graph theoretical partitioning. 相似文献
98.
Osamu Morikawa 《Tetrahedron letters》2006,47(24):3991-3994
The cyclocondensation of 1,3-dialkoxybenzenes with 1,3,5-trioxane was catalyzed by Sc(OTf)3 to produce resorcin[4]arene octaalkyl ethers as the major products. In addition, ‘confused’ resorcin[4]arene octaalkyl ethers bearing one alkoxy group at the intra-annular position were obtained as the minor products. The variable temperature 1H NMR spectroscopy showed that the alkoxy group at the intra-annular position cannot pass through the macrocyclic annulus, indicating a rigid molecular framework. The structure of the ethoxy derivative of the confused resorcin[4]arene was determined by X-ray crystallography. 相似文献
99.
Minoru Morikawa 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1962,13(2):167-175
Zusammenfassung Die Fokussierungseigenschaften eines aus schwachen Linsen bestehenden Systems unterhalb eines Beschleunigungsrohres sind studiert worden. Das System wird als dicke Linse in der Näherung der paraxialen Bahn behandelt. Die Kardinalelemente des Linsensystems können als Ganzes für den Fall, dass das Feld periodisch ist, in einfacher Form dargestellt werden.Im besondern sind die Ausdrücke für die Kardinalelemente eines Systems, das aus den Zweirohr-Immersionslinsen mit bestimmter Länge der Lücke zwischen den Rohren besteht, wiedergegeben. Die beigefügten Figuren erlauben, diese Elemente bequem zu berechnen. 相似文献
100.
Matsuda H Morikawa T Ohgushi T Ishiwada T Nishida N Yoshikawa M 《Chemical & pharmaceutical bulletin》2005,53(4):387-392
The methanolic extract from the flowers of Angelica furcijuga KITAGAWA was found to inhibit nitric oxide production in lipopolysaccharide-activated mouse peritoneal macrophages. From the methanolic extract, two new glycosides, hyuganosides IV and V, were isolated together with 28 known constituents. The structures of the new constituents were determined on the basis of chemical and physicochemical evidence. Furthermore, the inhibitory effects of 11 coumarin constituents on nitric oxide production were examined. Among them, 3'-angeloyl-cis-khellactone (IC(50)=82 microM), (S)-(-)-oxypeucedanin (57 microM), imperatorin (60 microM), isoepoxypteryxin (53 microM), and isopteryxin (8.8 microM) showed inhibitory activity. 相似文献