598 research outputs found

    Anisotropic Optic Conductivities due to Spin and Orbital Orderings in LaVO3 and YVO3: First-Principles Studies

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    The anisotropy of low energy (0\sim5eV) optical excitations in strongly correlated transition-metal oxides is closely related to the spin and orbital orderings. The recent successes of LDA+UU method in describing the magnetic and electronic structures enable us to calculate the optical conductivity from first-principles. The LaVO3_3 and YVO3_3, both of which have 3d23d^2 configuration and have various spin and orbital ordered phases at low temperature, show distinct anisotropy in the optical spectra. The effects of spin and orbital ordering on the anisotropy are studied in detail based on our first-principles calculations. The experimental spectra of both compounds at low temperature phases can be qualitatively explained with our calculations, while the studies for the intermediate temperature phase of YVO3_3 suggest the substantial persistence of the low temperature phase at elevated temperature.Comment: 6 pages, 3 figures, accepted by PR

    Unprecedented inequivalent metal coordination environments in a mixed-ligand dicobalt complex

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    Bimetallic complexes of the transition metals containing mixed diimine and dithiolate ligands are of fundamental interest on account of their intriguing electronic properties. Almost always, such complexes are isolated as species in which both the metal centers are in identical coordination environments - this means that the two metals often have identical redox properties. In contrast, mixed-diimine/dithiolate bimetallic complexes of the first row transition metals where the two metals are in dissimilar coordination environments are exceedingly rare, and are only known for nickel. Herein, we report the first ever example of a mixed-diimine/dithiolate dicobalt complex where the two cobalt centers are in different coordination environments. The synthesis of this compound is straightforward, and produces a complex in which the two cobalt centers display very different redox properties

    Real-time Forecasting of Time-evolving Controlled Sequence

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    本論文では,大規模制御応答時系列データストリームにおける制御量予測手法であるC-Castについて述べる.C-Castは,制御量(Controlled sequence),動作信号,操作量の三要素で構成される制御応答時系列データから,制御量の時系列パターンをとらえることで,パターン間の遷移に基づく高速な制御量予測を実現する.より具体的には,動作信号および操作量を考慮できるように動的システムを拡張し,制御応答時系列データを適応型動的システムとしてモデル化することで,重要なパターンや複雑なパターンの遷移を柔軟に表現する.提案手法は,(a)制御応答時系列データストリームから重要な特徴を発見し,刻々と変化していく潜在的なパターンやパターン遷移を高速かつ自動的に認識し,(b)将来的な制御量予測を実現する.さらに,提案手法は(c)データストリームの長さに依存しない.実データを用いた実験では,提案手法が制御応答時系列データストリームの中から重要な時系列パターンを発見し,制御量予測を高精度に行うことを確認した.さらに,最新の既存手法と比較し大幅な精度向上を達成し,その計算速度はデータサイズに依存せず,高速に動作することを明らかにした.Given a large collection of complex data sequences of control response, which consists of multiple attributes (e.g., Controlled sequence, Operation signal, Manipulated sequence), how can we effectively predict future controlled sequence? In this paper, we present C-Cast, an efficient and effective method for forecasting time-evolving data streams of control response. Our proposed method has the following properties: (a) Adaptive: it captures important time-evolving patterns and discontinuity in time-evolving data streams of control response. (b) Effective: it enables real-time controlled sequence forecasting. (c) Scalable: our algorithm does not depend on data size, and thus is applicable to very large sequences. Extensive experiments on a real dataset demonstrate that C-Castconsistently outperforms the best existing state-of-the-art methods as regards accuracy, and the execution speed is sufficiently fast

    Facile Fabrication of Ultrafine Hollow Silica and Magnetic Hollow Silica Nanoparticles by a Dual-Templating Approach

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    The development of synthetic process for hollow silica materials is an issue of considerable topical interest. While a number of chemical routes are available and are extensively used, the diameter of hollow silica often large than 50 nm. Here, we report on a facial route to synthesis ultrafine hollow silica nanoparticles (the diameter of ca. 24 nm) with high surface area by using cetyltrimethylammmonium bromide (CTAB) and sodium bis(2-ethylhexyl) sulfosuccinate (AOT) as co-templates and subsequent annealing treatment. When the hollow magnetite nanoparticles were introduced into the reaction, the ultrafine magnetic hollow silica nanoparticles with the diameter of ca. 32 nm were obtained correspondingly. Transmission electron microscopy studies confirm that the nanoparticles are composed of amorphous silica and that the majority of them are hollow

    Preparation of porous thin-film polymethylsiloxane microparticles in a W/O emulsion system

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    Porous thin-film polymethylsiloxane microparticles have been prepared successfully from octyltrichlorosilane and methyltrichlorosilane in (water/oil) W/O emulsion systems by using several oil phases and changing the amount of the silanes or of the surfactant Span 60. Hollow microspheres of various shell thicknesses (120-180 nm) and high surface area were prepared by using four types of nonpolar solvents as the oil phase of the W/O emulsion system. The diameter of the spheres can also be controlled (1-1.6 mu m) by using different oil phases. The results of thermal analysis, nitrogen adsorption isotherm, infrared spectra and X-ray diffraction data showed that hollow microspheres of amorphous polymethylsiloxane with high surface area (360-385 m(2)g(-1)) can be obtained by heating the spheres in air at 673 K; the polymethylsiloxane microspheres become nonporous silica particles after calcination at 873 K for 3 h. Cup-shape microparticles of polymethylsiloxane with nano-order thickness (20-120 nm) were prepared by reducing the amount of silanes in the mixture. Small hollow particles were prepared by replacing a portion of the octyltrichlorosilane with Span 60.ArticlePOLYMER JOURNAL. 47(6): 449-455 (2015)journal articl

    The C-terminal helical bundle of the tetrameric prokaryotic sodium channel accelerates the inactivation rate

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    Most tetrameric channels have cytosolic domains to regulate their functions, including channel inactivation. Here we show that the cytosolic C-terminal region of NavSulP, a prokaryotic voltage-gated sodium channel cloned from Sulfitobacter pontiacus, accelerates channel inactivation. The crystal structure of the C-terminal region of NavSulP grafted into the C-terminus of a NaK channel revealed that the NavSulP C-terminal region forms a four-helix bundle. Point mutations of the residues involved in the intersubunit interactions of the four-helix bundle destabilized the tetramer of the channel and reduced the inactivation rate. The four-helix bundle was directly connected to the inner helix of the pore domain, and a mutation increasing the rigidity of the inner helix also reduced the inactivation rate. These findings suggest that the NavSulP four-helix bundle has important roles not only in stabilizing the tetramer, but also in accelerating the inactivation rate, through promotion of the conformational change of the inner helix

    Augmented TLR2 Expression on Monocytes in both Human Kawasaki Disease and a Mouse Model of Coronary Arteritis

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    BACKGROUND: Kawasaki disease (KD) of unknown immunopathogenesis is an acute febrile systemic vasculitis and the leading cause of acquired heart diseases in childhood. To search for a better strategy for the prevention and treatment of KD, this study compared and validated human KD immunopathogenesis in a mouse model of Lactobacillus casei cell wall extract (LCWE)-induced coronary arteritis. METHODS: Recruited subjects fulfilled the criteria of KD and were admitted for intravenous gamma globulin (IVIG) treatment at the Kaohsiung Chang Gung Memorial Hospital from 2001 to 2009. Blood samples from KD patients were collected before and after IVIG treatment, and cardiovascular abnormalities were examined by transthoracic echocardiography. Wild-type male BALB/c mice (4-week-old) were intraperitoneally injected with LCWE (1 mg/mL) to induce coronary arteritis. The induced immune response in mice was examined on days 1, 3, 7, and 14 post injections, and histopathology studies were performed on days 7 and 14. RESULTS: Both human KD patients and LCWE-treated mice developed coronary arteritis, myocarditis, valvulitis, and pericarditis, as well as elevated plasma levels of interleukin (IL)-2, IL-6, IL-10, monocyte chemoattractant protein (MCP)-1, and tumor necrosis factor (TNF)-α in acute phase. Most of these proinflammatory cytokines declined to normal levels in mice, whereas normal levels were achieved in patients only after IVIG treatment, with a few exceptions. Toll-like receptor (TLR)-2, but not TLR4 surface enhancement on circulating CD14+ monocytes, was augmented in KD patients before IVIG treatment and in LCWE-treated mice, which declined in patients after IVIG treatment. CONCLUSION: This result suggests that that not only TLR2 augmentation on CD14+ monocytes might be an inflammatory marker for both human KD patients and LCWE-induced CAL mouse model but also this model is feasible for studying therapeutic strategies of coronary arteritis in human KD by modulating TLR2-mediated immune activation on CD14+ monocytes
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