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71.
For self-interstitial atom (SIA) clusters in various concentrated alloys, one-dimensional (1D) migration is induced by electron irradiation around 300 K. But at elevated temperatures, the 1D migration frequency decreases to less than one-tenth of that around 300 K in iron-based bcc alloys. In this study, we examined mechanisms of 1D migration at elevated temperatures using in situ observation of SUS316L and its model alloys with high-voltage electron microscopy. First, for elevated temperatures, we examined the effects of annealing and short-term electron irradiation of SIA clusters on their subsequent 1D migration. In annealed SUS316L, 1D migration was suppressed and then recovered by prolonged irradiation at 300 K. In high-purity model alloy Fe-18Cr-13Ni, annealing or irradiation had no effect. Addition of carbon or oxygen to the model alloy suppressed 1D migration after annealing. Manganese and silicon did not suppress 1D migration after annealing but after short-term electron irradiation. The suppression was attributable to the pinning of SIA clusters by segregated solute elements, and the recovery was to the dissolution of the segregation by interatomic mixing under electron irradiation. Next, we examined 1D migration of SIA clusters in SUS316L under continuous electron irradiation at elevated temperatures. The 1D migration frequency at 673 K was proportional to the irradiation intensity. It was as high as half of that at 300 K. We proposed that 1D migration is controlled by the competition of two effects: induction of 1D migration by interatomic mixing and suppression by solute segregation. 相似文献
72.
To achieve immune homeostasis in such a harsh environment as the intestinal mucosa, both active and quiescent immunity operate simultaneously. Disruption of gut immune homeostasis leads to the development of intestinal immune diseases such as colitis and food allergies. Among various intestinal innate immune cells, mast cells (MCs) play critical roles in protective immunity against pathogenic microorganisms, especially at mucosal sites. This suggests the potential for a novel MC-targeting type of vaccine adjuvant. Dysregulated activation of MCs also results in inflammatory responses in mucosal compartments. The regulation of this yin and yang function of MCs remains to be elucidated. In this review, we focus on the roles of mucosal MCs in the regulation of intestinal allergic reaction, inflammation and their potential as a new target for the development of mucosal adjuvants. 相似文献
73.
Huihui Li Yosuke Imai Takanori Takiue Hiroki Matsubara Makoto Aratono 《Colloid and polymer science》2014,292(5):1209-1215
The composition of the adsorbed film and the excess Gibbs energy of adsorption $ {\widehat{g}}^{\mathrm{H},\mathrm{E}} $ were evaluated from thermodynamic analysis of surface tensions for the 1-decyl-3-methylimidazoulium bromide (C10mimBr)–tetraethylene glycol monooctyl ether (C8E4) and 1-decyl-3-methyl-imidazolium tetrafluorobrorate (C10mimBF4)–C8E4 systems, where the counter anion of imidazolium salts is different from each other. The higher miscibility of two components compared to an ideal mixing and thus negative $ {\widehat{g}}^{\mathrm{H},\mathrm{E}} $ were observed in the former, which comes from the ion–dipole interaction between imidazolium cation and the oxyethylene group of C8E4. On the other hand, the lower miscibility and thus positive $ {\widehat{g}}^{\mathrm{H},\mathrm{E}} $ were observed for the latter. Such differences were attributed to that BF4 ? forms two hydrogen bonds and has stronger affinity with the cationic head group of C10mim+ than Br?. This results in that the ion–dipole interaction between C8E4 and C10mim+ cation is diminished in the C10mimBF4–C8E4 system. 相似文献
74.
Prof. Nobutaka Fujieda Kyohei Umakoshi Yuta Ochi Dr. Yosuke Nishikawa Prof. Sachiko Yanagisawa Prof. Minoru Kubo Prof. Genji Kurisu Prof. Shinobu Itoh 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(32):13487-13492
The dinuclear copper enzyme, tyrosinase, activates O2 to form a (μ-η2:η2-peroxido)dicopper(II) species, which hydroxylates phenols to catechols. However, the exact mechanism of phenolase reaction in the catalytic site of tyrosinase is still under debate. We herein report the near atomic resolution X-ray crystal structures of the active tyrosinases with substrate l -tyrosine. At their catalytic sites, CuA moved toward l -tyrosine (CuA1 → CuA2), whose phenol oxygen directly coordinates to CuA2, involving the movement of CuB (CuB1 → CuB2). The crystal structures and spectroscopic analyses of the dioxygen-bound tyrosinases demonstrated that the peroxide ligand rotated, spontaneously weakening its O−O bond. Thus, the copper migration induced by the substrate-binding is accompanied by rearrangement of the bound peroxide species so as to provide one of the peroxide oxygen atoms with access to the phenol substrate's ϵ carbon atom. 相似文献
75.
Hayate Saito Keita Yamamoto Yosuke Sumiya Ling‐Jun Liu Keisuke Nogi Satoshi Maeda Hideki Yorimitsu 《化学:亚洲杂志》2020,15(16):2442-2446
C?H iodination of aromatic compounds has been accomplished with the aid of sulfinyl directing groups under palladium catalysis. The reaction proceeds selectively at the peri‐position of polycyclic aryl sulfoxides or at the ortho‐position of phenyl sulfoxides. The iodination products can be further converted via iterative catalytic cross‐coupling at the expense of the C?I and C?S bonds. Computational studies suggest that peri‐C?H palladation would proceed via a non‐directed pathway, wherein neither of the sulfur nor oxygen atom of the sulfinyl group coordinates to the palladium before and at the transition state. 相似文献
76.
Optical Review - We demonstrate distributed measurement of the polarization beat length along single-mode optical fibers (SMFs) using slope-assisted Brillouin optical correlation-domain... 相似文献
77.
78.
Masahiro Yamashita Daisuke Kawakami Satoshi Matsunaga Yoshio Nakayama Mari Sasaki Shinya Takaishi Fumiyasu Iwahori Hitoshi Miyasaka Ken‐ichi Sugiura Yoshiki Wada Hiroshi Miyamae Hiroyuki Matsuzaki Hiroshi Okamoto Hisaaki Tanaka Kazuhiro Marumoto Shin‐ichi Kuroda 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2004,116(36):4867-4871
79.
Takashi Minoshima Yosuke Matsumoto Takanobu Amano 《Journal of computational physics》2011,230(17):6800-6823
We present a new numerical scheme for solving the advection equation and its application to Vlasov simulations. The scheme treats not only point values of a profile but also its zeroth to second order piecewise moments as dependent variables, for better conservation of the information entropy. We have developed one-and two-dimensional schemes and show that they provide quite accurate solutions within reasonable usage of computational resources compared to other existing schemes. The two-dimensional scheme can accurately solve the solid body rotation problem of a gaussian profile for more than hundred rotation periods with little numerical diffusion. This is crucially important for Vlasov simulations of magnetized plasmas. Applications of the one- and two-dimensional schemes to electrostatic and electromagnetic Vlasov simulations are presented with some benchmark tests. 相似文献
80.
Water‐ and Temperature‐Triggered Reversible Structural Transformation of Tetranuclear Cobalt(II) Cores Sandwiched by Polyoxometalates 下载免费PDF全文
Yosuke Kuriyama Dr. Yuji Kikukawa Dr. Kosuke Suzuki Dr. Kazuya Yamaguchi Prof. Dr. Noritaka Mizuno 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(12):3962-3966
Although stimuli‐responsive structural transformations of inorganic materials have attracted considerable attention because of their potential use as functional switchable materials, multinuclear metal cores frequently suffer from unexpected dissociation of metal cations and/or irreversible transformations into infinite structures. In this study, we describe the successful demonstration of the water‐ and temperature‐triggered reversible structural transformation between cubane‐ and planar‐type tetranuclear CoII cores sandwiched by polyoxometalates. The arrangements and coordination geometries of the CoII cations were interconverted by simple hydration and dehydration, resulting in the manipulation of the magnetic and optical properties of these compounds. Moreover, this system showed unique thermochromism through temperature‐dependent reversible structural interconversion. 相似文献