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排序方式: 共有541条查询结果,搜索用时 62 毫秒
1.
Direct Introduction of a Dimesitylboryl Group Using Base‐Mediated Substitution of Aryl Halides with Silyldimesitylborane 下载免费PDF全文
Dr. Eiji Yamamoto Kiyotaka Izumi Ryosuke Shishido Prof. Dr. Tomohiro Seki Noriaki Tokodai Prof. Dr. Hajime Ito 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(49):17547-17551
The first dimesitylboryl substitution of aryl halides with a silylborane bearing a dimesitylboryl group in the presence of alkali‐metal alkoxides is described. The reactions of aryl bromides or iodides with Ph2MeSi?BMes2 and Na(OtBu) afforded the desired aryl dimesitylboranes in good to high yields and with high borylation/silylation ratios. Selective reaction of the sterically less‐hindered C?Br bond of dibromoarenes provided monoborylated products. This reaction was used to rapidly construct a D‐π‐A aryl dimesityl borane with a non‐symmetrical biphenyl spacer. 相似文献
2.
A new periodic pattern with five‐neighbored domain packing from ABC triblock terpolymer/B homopolymer blend 下载免费PDF全文
Yuki Izumi Mutsuhiko Yamada Atsushi Takano Yushu Matsushita 《Journal of Polymer Science.Polymer Physics》2015,53(13):907-911
Self‐assembled structures from poly(isoprene‐b‐styrene‐b‐2‐vinylpyridine)(ISP)/styrene homopolymer blend were investigated. Five terpolymers whose total molecular weight, M, is in the narrow range of 121k < M < 214k, and volume fractions of the center block polystyrenes, ?S, are similar at around 0.55, were prepared as parent block terpolymers. Their ?P/?I ratios, used as an indicator of asymmetry, are varied in the range 0.32 < ?P/?I < 2.46. Three low‐molecular weight styrene homopolymers with molecular weights of 3k, 9k, and 12k, respectively, were mixed with those block terpolymers to produce blends with almost constant styrene content within the range 0.65 < ?S < 0.68. Both ISP/S(3k) and ISP/S(12k) blend series show a morphological transition from tetragonally packed cylinders (TPC) to double hexagonal structure (DHS) with hexagonally arrayed polyisoprene cylinders, each surrounded by six thin cylinders as satellites. If one focuses on ISP‐III(150k)/S blends whose ?P/?I is 0.88, TPC for ISP‐III/S(3k) was transformed to DHS for ISP‐III/S(12k), evidently due to the molecular weight effect of the added homopolymer. Finally a new periodic pattern, having P cylinders surrounded by five I cylinders each, has been discovered from ISP‐III/S(9k) at overall composition of ?I/?S/?P = 0.17/0.68/0.15 and polystyrene block/styrene homopolymer ratio of wS(b)/wS(h) = 1.4. This structure was confirmed to possess hexagonal symmetry with larger unit cell than regular patterns ever known by X‐ray diffraction experiment. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 907–911 相似文献
3.
A self-propelled object coupled with an enzyme reaction between urease and urea was investigated at the air/aqueous interface. A plastic object that was fixed to a urease-immobilized filter paper was used as a self-propelled object, termed a urease motor, placed on an aqueous urea solution. The driving force of the urease motor is the difference in the surface tension around the object. Oscillatory motion or no motion was triggered depending on the initial pH of the urea solution. Both the frequency and maximum speed of the oscillatory motion varied depending on the initial pH of the water phase. The mechanisms underlying the oscillatory motion and no motion were discussed in relation to the bell-shaped enzyme activity of urease in the enzyme reaction and the surface tension around the urease motor. 相似文献
4.
Yohei Saito Atsushi Mizokami Kouji Izumi Renato Naito Masuo Goto Kyoko Nakagawa-Goto 《Molecules (Basel, Switzerland)》2021,26(9)
α-Trifluoromethyl chalcones were prepared and evaluated for their antiproliferative activities against androgen-independent prostate cancer cell lines as well as five additional types of human tumor cell lines. The most potent chalcone 5 showed superior antitumor activity in vivo with both oral and intraperitoneal administration at 3 mg/kg. Cell-based mechanism of action studies demonstrated that 5 induced cell accumulation at sub-G1 and G2/M phases without interfering with microtubule polymerization. Furthermore, several cancer cell growth-related proteins were identified by using chalcone 5 as a bait for the affinity purification of binding proteins. 相似文献
5.
Shuzo Izumi 《代数通讯》2013,41(12):3885-3889
The definition of stabilizer and orbit for Hopf algebra action is given, and a duality theorem on stabilizer is proved. 相似文献
6.
A high‐performance liquid chromatography assay with a triazole‐bonded column for evaluation of d‐amino acid oxidase activity 下载免费PDF全文
Megumi Iwasaki Yoshiyuki Kashiwaguma Chihiro Nagashima Mao Izumi Ayano Uekusa Sumiko Iwasa Mayu Onozato Hideaki Ichiba Takeshi Fukushima 《Biomedical chromatography : BMC》2016,30(3):384-389
Elution profiles of kynurenic acid (KYNA) and 7‐chlorokynurenic acid (Cl‐KYNA) were examined by high‐performance liquid chromatography (HPLC) using a triazole‐bonded stationary phase column (Cosmosil® HILIC) under isocratic elution of a mobile phase consisting of CH3CN–aqueous 10 mm ammonium formate between pH 3.0 and 6.0. The capacity factors of KYNA and Cl‐KYNA varied with both the CH3CN content and the pH of the mobile phase. The elution order of KYNA and Cl‐KYNA was reversed between the CH3CN‐ and H2O‐rich mobile phases, suggesting that hydrophilic interactions and anion‐exchange interactions caused retention of KYNA and Cl‐KYNA in the CH3CN‐ and H2O‐rich mobile phases, respectively. The present HPLC method using a triazole‐bonded column and fluorescence detection (excitation 250 nm, emission 398 nm) was applied to monitor in vitro production of KYNA from d ‐kynurenine (d ‐KYN) by d ‐amino acid oxidase (DAO) using Cl‐KYNA as an internal standard. A single KYNA peak was clearly observed after enzymatic reaction of d ‐KYN with DAO. Production of KYNA from d ‐KYN was suppressed by the addition of commercial DAO inhibitors. The present HPLC method can be used to evaluate DAO activity and DAO inhibitory effects in candidate drugs for the treatment of schizophrenia. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
7.
Optical Review - We investigate a method to evaluate light-scattering properties and chromophore concentrations in human skin tissue through diffuse reflectance spectroscopy using the reflectance... 相似文献
8.
Mitsuru Izumi Toshiki Nakayama Kunimitsu Uchinokura Ryozo Yoshizaki Etsuyuki Matsuura 《Molecular Crystals and Liquid Crystals》2013,570(1-4):79-82
Metallic phase of NbS3 was synthesized by heating the crystal of semiconducting NbS3. Metallic NbS3 undergoes superconducting transition around 2 K. The analysis of the angular dependence of the upper critical magnetic field suggests that the effect of filmy or fibrous morphology plays an important role in the superconducting properties. 相似文献
9.
Tomonori Yuasa Ryosuke Honma Hideki Funamizu Izumi Nishidate Yoshihisa Aizu 《Optical Review》2014,21(3):369-372
We are developing a daily health monitoring system that uses mobile phones with cameras and analyzes physiological conditions from R, G, and B intensity levels. However, since it is affected by various imaging conditions of the image input, color correction is required for accurate health monitoring. Therefore, we developed and validated a colorcorrection algorithm to derive reliable color information by correcting the spectral reflectance using the Wiener estimation and a color chart. 相似文献
10.