948 research outputs found

    Superconductivity in metal rich Li-Pd-B ternary Boride

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    8K superconductivity was observed in the metal rich Li-Pd-B ternary system. Structural, microstructural, electrical and magnetic investigations for various compositions proved that Li2Pd3B compound, which has a cubic structure composed of distorted Pd6B octahedrons, is responsible for the superconductivity. This is the first observation of superconductivity in metal rich ternary borides containing alkaline metal and Pd as a late transition metal. The compound prepared by arc melting has high density, is stable in the air and has an upper critical field, Hc2(0), of 6T.Comment: 4 pages, 5 figur

    An Interactive Modeling Support System (IMSS)

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    A computer-assisted mathematical modeling method that emphasizes the interaction between analysts and computers is presented. It combines algebraic and graph-theoretic approaches to extract a trade-off between human mental models and models based on the use of data collected from the system under study. The method is oriented to the modeling of the so-called "gray box" systems which often involve human behavioral aspects and also knowledge of the experts in relevant fields. By recursive dialogues with the computer, the modeler finds a system model which can be nonlinear with respect to descriptive variables. The structure of the computer program packages is also presented

    Toward Advanced Computer-Assisted Modeling

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    A mathematically elaborated modeling method alone cannot develop useful models of large-scale systems that involve human activities. What is needed as input to the model-building process, besides measurement data, is the knowledge of experts in relevant fields. The problem is, then, what types of knowledge should or can be included in the modeling process and, more important, how do we manage them. The interactive method of data handling (IMDH) presented in this paper develops linear models of complex systems through recursive interaction with the computer, systematically introducing the expert's knowledge about the structure of the underlying system. It should be emphasized that the more one repeats dialogues with the computer, the more effectively knowledge can be used to develop and refine the model

    Raft-derived tau-associated vesicles

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    Aims: Neurofibrillary tangles (NFTs), a cardinal pathological feature of neurodegenerative disorders, such as Alzheimer's disease (AD) are primarily composed of hyper‐phosphorylated tau protein. Recently, several other molecules, including flotillin‐1, phosphatidylinositol‐4,5‐bisphosphate [PtdIns(4,5)P2] and cyclin‐dependent kinase 5 (CDK5), have also been revealed as constituents of NFTs. Flotillin‐1 and PtdIns(4,5)P2 are considered markers of raft microdomains, whereas CDK5 is a tau kinase. Therefore, we hypothesized that NFTs have a relationship with raft domains and the tau phosphorylation that occurs within NFTs. Methods: We investigated six cases of AD, six cases of other neurodegenerative diseases with NFTs and three control cases. We analysed the PtdIns(4,5)P2‐immunopositive material in detail, using super‐resolution microscopy and electron microscopy to elucidate its pattern of expression. We also investigated the spatial relationship between the PtdIns(4,5)P2‐immunopositive material and tau kinases through double immunofluorescence analysis. Results: Pretangles contained either paired helical filaments (PHFs) or PtdIns(4,5)P2‐immunopositive small vesicles (approximately 1 μm in diameter) with nearly identical topology to granulovacuolar degeneration (GVD) bodies. Various combinations of these vesicles and GVD bodies, the latter of which are pathological hallmarks observed within the neurons of AD patients, were found concurrently in neurons. These vesicles and GVD bodies were both immunopositive not only for PtdIns(4,5)P2, but also for several tau kinases such as glycogen synthase kinase‐3β and spleen tyrosine kinase. Conclusions: These observations suggest that clusters of raft‐derived vesicles that resemble GVD bodies are substructures of pretangles other than PHFs. These tau kinase‐bearing vesicles are likely involved in the modification of tau protein and in NFT formation

    Thermodynamic and Transport Properties of CeMg2Cu9 under Pressure

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    We report the transport and thermodynamic properties under hydrostatic pressure in the antiferromagnetic Kondo compound CeMg2Cu9 with a two-dimensional arrangement of Ce atoms. Magnetic specific heat Cmag(T) shows a Schottky-type anomaly around 30 K originating from the crystal electric field (CEF) splitting of the 4f state with the first excited level at \Delta_{1}/kB = 58 K and the second excited level at \Delta_{2}/kB = 136 K from the ground state. Electric resistivity shows a two-peaks structure due to the Kondo effect on each CEF level around T_{1}^{max} = 3 K and T_{2}^{max} = 40 K. These peaks merge around 1.9 GPa with compression. With increasing pressure, Neel temperature TN initially increases and then change to decrease. TN finally disappears at the quantum critical point Pc = 2.4 GPa.Comment: 10 pages, 6 figure

    Size-changeable x-ray beam collimation using an adaptive x-ray optical system based on four deformable mirrors

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    T. Goto, S. Matsuyama, H. Nakamori, H. Hayashi, Y. Sano, Y. Kohmura, M. Yabashi, T. Ishikawa, and K. Yamauchi "Size-changeable x-ray beam collimation using an adaptive x-ray optical system based on four deformable mirrors", Proc. SPIE 9965, Adaptive X-Ray Optics IV, 996502 (27 October 2016); https://doi.org/10.1117/12.2238794
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