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1.
2.
We consider the problem of minimum risk point estimation for the parameter =a+b of the exponential distribution with unknown location parameter and scale parameter when the loss function is squared error plus linear cost. In this paper, we propose a sequential estimator of and show that the associated risk is asymptotically one cost less than that given by Ghosh and Mukhopadhyay (1989,South African Statist. J.,23, 251–268). 相似文献
3.
Two trans stereoisomers of 3‐methylcyclopentadecanol (=muscol), (1R,3R)‐ 2 and (1S,3S)‐ 2 , were efficiently synthesized from (3RS)‐3‐methylcyclopentadecanone (=muscone; (3RS)‐ 1 ) by a highly stereoselective reduction (Scheme). L‐Selectride® (=lithium tri(sec‐butyl)borohydride) was used, followed by the enantiomer resolution by lipase QLG (Alcaligenes sp.). The cis stereoisomers of muscol, (1S,3R)‐ 2 and (1R,3S)‐ 2 , were obtained by the Mitsunobu inversion of (1R,3R)‐ 2 and (1S,3S)‐ 2 , respectively (Scheme). The absolute configuration of (1R,3R)‐ 2 was determined by X‐ray crystal‐structure analysis of its 3‐nitrophthalic acid monoester, 2‐[(1R,3R)‐3‐methylcyclopentadecyl hydrogen benzene‐1,2‐dicarboxylate ((1R,3R)‐ 3b ), and by oxidation of (1R,3R)‐ 2 to (3R)‐muscone. 相似文献
4.
Isao Takahashi Fumika Morita Shunsuke Kusagaya Haruhiko Fukaya Osamu Kitagawa 《Tetrahedron: Asymmetry》2012,23(24):1657-1662
In the presence of an (R)-MOP-Pd2(dba)3 catalyst, the reaction of ortho-tert-butylaniline with 2-bromophenyl arylethynyl ketone proceeded via a tandem amination (1,4-addition of aniline to an ynone and subsequent intramolecular Buchwald–Hartwig amination) to afford axially chiral N-(2-tert-butylphenyl)-2-aryl-4-quinolinone derivatives with moderate enantioselectivity (up to 72% ee). 相似文献
5.
Yutaka Aoyagi Kei Ozawa Tatsuya Kobayashi Tomoyo Hasuda Ming-Yu Gui Yong-Ri Jin Xu-Wen Li Haruhiko Fukaya Reiko Yano Yukio Hitotsuyanagi Koichi Takeya 《Tetrahedron》2014
Transformation of plant-origin 7,14-dihydroxy-ent-kaurenes to ent-abietanes having a cis-fused α-methylene γ-lactones was accomplished efficiently under the Mitsunobu reaction conditions. The yields of the desired products were apparently influenced by the steric hindrance at C-1. The cytotoxic activity on P388 murine leukemia cells of the ent-abietanes having cis-fused α-methylene γ-lactones produced were assayed. 相似文献
6.
Dr. Changfeng Hong Takahiro Otabe Saki Matsumoto Dr. Chikara Dohno Dr. Asako Murata Dr. Masaki Hagihara Prof. Dr. Kazuhiko Nakatani 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(18):5282-5287
The hairpin structure is one of the most common secondary structures in RNA and holds a central position in the stream of RNA folding from a non‐structured RNA to structurally complex and functional ribonucleoproteins. Since the RNA secondary structure is strongly correlated to the function and can be modulated by the binding of small molecules, we have investigated the modulation of RNA folding by a ligand‐assisted formation of loop–loop complexes of two RNA hairpin loops. With a ligand (NCT6), designed based on the ligand binding to the G–G mismatches in double‐stranded DNA, we successfully demonstrated the formation of both inter‐ and intra‐molecular NCT6‐assisted complex of two RNA hairpin loops. NCT6 selectively bound to the two hairpin loops containing (CGG)3 in the loop region. Native polyacrylamide gel electrophoresis analysis of two doubly‐labeled RNA hairpin loops clearly showed the formation of intermolecular NCT6‐assisted loop–loop complex. Förster resonance energy‐transfer studies of RNA constructs containing two hairpin loops, in which each hairpin was labeled with Alexa488 and Cy3 fluorophores, showed the conformational change of the RNA constructs upon binding of NCT6. These experimental data showed that NCT6 simultaneously bound to two hairpin RNAs at the loop region, and can induce the conformational change of the RNA molecule. These data strongly support that NCT6 functions as molecular glue for two hairpin RNAs. 相似文献
7.
Dr. Vibe B. Jakobsen Dr. Elzbieta Trzop Dr. Laurence C. Gavin Emiel Dobbelaar Dr. Shalinee Chikara Dr. Xiaxin Ding Dr. Kane Esien Dr. Helge Müller-Bunz Dr. Solveig Felton Dr. Vivien S. Zapf Prof. Eric Collet Prof. Michael A. Carpenter Prof. Grace G. Morgan 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(32):13407-13414
Domain wall motion is detected for the first time during the transition to a ferroelastic and spin state ordered phase of a spin crossover complex. Single-crystal X-ray diffraction and resonant ultrasound spectroscopy (RUS) revealed two distinct symmetry-breaking phase transitions in the mononuclear Mn3+ compound [Mn(3,5-diBr-sal2(323))]BPh4, 1. The first at 250 K, involves the space group change Cc→Pc and is thermodynamically continuous, while the second, Pc→P1 at 85 K, is discontinuous and related to spin crossover and spin state ordering. Stress-induced domain wall mobility was interpreted on the basis of a steep increase in acoustic loss immediately below the the Pc-P1 transition 相似文献
8.
Sekiguchi A Ishida Y Fukaya N Ichinohe M Takagi N Nagase S 《Journal of the American Chemical Society》2002,124(7):1158-1159
Dark red crystals of the halogen-substituted cyclotrigermenes [(tBu3Si)3Ge3X; X = Cl, Br, I] were obtained in good yields by the reaction of [(tBu3Si)3Ge3]+.TTFPB- (TTFPB- = tetrakis(2,3,5,6-tetrafluorophenyl)borate) with potassium halides (KCl, KBr, or KI) in diethyl ether. The crystal structures of the halogen-substituted cyclotrigermenes reveal a cis-bent Ge=Ge double bond, caused by the introduction of the electronegative halogen atom on the sp3 germanium atom of cyclotrigermene. In solution, an intramolecular halogen migration over the three-membered ring skeleton was observed. Facial stereoselectivity in the Diels-Alder reaction of new cyclotrigermenes with 2,3-dimethyl-1,3-butadiene is also reported. 相似文献
9.
Yoshio Hayakawa Eiji Hayashi Haruhiko Fukaya Naohiro Terasawa Takashi Abe Kota Omori Koichi Murai 《Liquid crystals》1996,20(3):367-371
Novel liquid crystals which have the perfluoropyrrolidino group, a heterocyclic perfluoroalkyl group, and which show smectic phases have been synthesized with perfluoro-(2-pyrrolidinopropionyl fluoride) as one of the starting materials. Analogues with a polymerizable functional group also have been prepared and polymerized to give side chain liquid crystal polymers. 相似文献
10.
Savici AT Fukaya A Gat-Malureanu IM Ito T Russo PL Uemura YJ Wiebe CR Kyriakou PP MacDougall GJ Rovers MT Luke GM Kojima KM Goto M Uchida S Kadono R Yamada K Tajima S Masui T Eisaki H Kaneko N Greven M Gu GD 《Physical review letters》2005,95(15):157001
Muon spin relaxation measurements in high transverse magnetic fields [FORMULA: SEE TEXT] revealed strong field-induced quasistatic magnetism in the underdoped and Eu-doped (La,Sr)2CuO4 and La1.875Ba0.125CuO4, existing well above Tc and TN. The susceptibility counterpart of Cu spin polarization, derived from the muon spin relaxation rate, exhibits a divergent behavior towards T approximately 25 K. No field-induced magnetism was detected in overdoped La1.81Sr0.19CuO4, optimally doped Bi2212, and Zn-doped YBa2Cu3O7. 相似文献