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排序方式: 共有258条查询结果,搜索用时 15 毫秒
41.
42.
Morikawa T Nakamura S Kato Y Muraoka O Matsuda H Yoshikawa M 《Chemical & pharmaceutical bulletin》2007,55(2):293-298
New triterpene saponins, foliatheasaponins I-V, were isolated from the methanolic extract of Tencha [the leaves of Camellia sinensis (L.) O. KUNTZE (Theaceae)]. The chemical structures of these new saponins were elucidated on the basis of chemical and physicochemical evidence. Among the new saponins, foliatheasaponins II and III, were found to inhibit release of beta-hexosaminidase, as a marker of antigen-induced degranulation, in RBL-2H3 cells. 相似文献
43.
S. Nagao T. Matsunaga S. Muraoka 《Journal of Radioanalytical and Nuclear Chemistry》1999,239(3):555-559
Geochemical association of137Cs and239,240Pu in the surface sediments from two oligotrophic and mesotrophic lakes in Japan was studied by sequential chemical extractions.
The fractions separated were exchangeable and bound to carbonate, bound to oxides, bound to organic mattersulfides, and residual.
The137Cs and239,240Pu were mainly associated with the organic matter-sulfides and residual fractions but exhibited the different vertical profiles
at both lakes. The differences in association patterns between the lakes may be controlled by transport of these nuclides
by organic settling particles to the bottom sediments and decomposition of the organics in the sediments. 相似文献
44.
45.
R. Yoshida H. Okazaki K. Iwai K. Noami T. Muro M. Okawa K. Ishizaka S. Shin Z. Li J.L. Luo G.-Q. Zheng T. Oguchi M. Hirai Y. Muraoka T. Yokoya 《Physica C: Superconductivity and its Applications》2009,469(15-20):1034-1036
We present the data from ultrahigh-resolution laser-excited photoemission spectroscopy on a newly discovered noncentrosymmetric superconductor Mg10Ir19B16. We observed the evidences for the opening of superconducting gap where numerical fittings show that isotropic s-wave model can satisfactorily explain the behavior of spectra near the Fermi level. We also present the valence band photoemission spectrum and B K fluorescence spectrum to discuss the basic electronic structure of Mg10Ir19B16. 相似文献
46.
Harayama Y Yoshida M Kamimura D Wada Y Kita Y 《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(18):4893-4899
Hypervalent iodine(III) reagents are readily available, easy to handle, and have a low toxicity and similar reactivities to those of heavy metal reagents, and hence they are used for various oxidative reactions. The oxidative cleavage of alkynes or carbonyl compounds by using bis(trifluoroacetoxy)iodo(III) pentafluorobenzene (C(6)F(5)I(OCOCF(3))(2)) has been reported. Herein, the efficient direct synthesis of N,O-acetal compounds as key intermediates of discorhabdin A, by the oxidative fragmentation reaction of alpha-amino acids or beta-amino alcohols by using C(6)F(5)I(OCOCF(3))(2), is described. 相似文献
47.
Copper(I)-catalyzed alkynylation-cyclization of 4-oxahepta-1,6-diynes 1 with a wide variety of terminal alkynes proceeded to give (3E,4Z)-3-(phenylsulfanylmethylene)-4-(2-propynylidene)tetrahydrofuran-2-yl]benzenes 2aa-he in high yields with complete regio- and stereoselectivity. 相似文献
48.
Yasushi Kanai Yoshihiro JinboKazuya Koyama Kazuetsu YoshidaSimon Greaves Hiroaki Muraoka 《Journal of magnetism and magnetic materials》2012,324(3):282-286
Landau-Lifshitz-Gilbert micromagnetic models were used to analyze the head field distributions and high-frequency responses for various soft magnetic underlayer thicknesses (t-SUL) and saturation magnetization flux densities (Bs) of single-pole-type (SPT) head-SUL systems. It was found that Bs of 10-12 kG and t-SUL of 30-45 nm would be sufficient for the examined head and perhaps for most next generation head-SUL systems. Antiferromagnetic coupling in the SUL affects the head and SUL magnetization and, eventually, the head field. With regard to the head magnetization response, it was found that the magnetization under the coil responded first, while the response at the main pole tip was quite slow, even compared with the head field. The main pole tip of the head was fully saturated and the main pole yoke was almost saturated, while the SUL was not saturated in the examined head-SUL system. 相似文献
49.
Kanemichi Muraoka Miharu Eguchi Osamu Ishitani Francois Chevire Kazuhiko Maeda 《Journal of Energy Chemistry》2021,(4):176-182
Hybrid materials constructed from a visible-light-absorbing semiconductor and a functional metal complex have attracted attention as efficient photocatalysts for CO2 reduction with high selectivity to a desired product.In this work,defect fluorite-type Ln-Ta oxynitrides LnTaOxNy(Ln=Nd,Sm,Gd,Tb,Dy and Ho)were examined as the semiconductor component in a hybrid photocatalyst system combined with known Ag nanoparticle promoter and binuclear ruthenium(Ⅱ)complex(RuRu’).Among the LnTaOxNy examined,TbTaOxNy gave the highest performance for CO2 reduction under visible light(k>400 nm),with a Ru Ru0-based turnover number of 18 and high selectivity to formate(>99%).Physicochemical analyses indicated that high crystallinity and more negative conduction band potential of Ln Ta OxNywith the absence of Ln-4 f states in the band gap structure contributed to higher activity of the hybrid photocatalyst. 相似文献
50.
Atsuya Ishida Prof. Go Watanabe Dr. Mio Oshikawa Prof. Itsuki Ajioka Prof. Takahiro Muraoka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(59):13523-13530
Self-assembling peptides that are capable of adopting β-sheet structures can generate nanofibers that lead to hydrogel formation. Herein, to tune the supramolecular morphologies, mechanical properties, and stimuli responses of the hydrogels, we investigated glycine substitution in a β-sheet-forming amphiphilic peptide. Glycine substitution generally enhances conformational flexibility. Indeed, glycine substitution in an amphiphilic peptide weakened the hydrogels or even inhibited the gelation. However, unexpectedly, glycine substitution at the center of the peptide molecule significantly enhanced the hydrogel stiffness. The central glycine substitution affected the molecular packing and led to twisted β-sheet structures and to nanofiber bundling, which likely led to the stiffened hydrogel. Importantly, the supramolecular structures were accurately predicted by molecular dynamics simulations, demonstrating the helpfulness of these techniques for the identification of self-assembling peptides. The hydrogel formed by the amphiphilic peptide with the central glycine substitution had cell adhesive function, and showed a reversible thermal gel-to-sol transition. Thus, glycine substitution is effective in modulating self-assembling structures, rheological properties, and dynamics of biofunctional self-assembling peptides. 相似文献