174 research outputs found

    A study of the measures of effectiveness for the JMSDF Aegis destroyer in a littoral, air defense environment

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    Maritime operations in a littoral area demand a fundamental change in the future defense build-up of the Japanese Maritime Self Defense Force (JMSDF). The anti-air warfare (AAW) capability of the JMSDF in the littoral area, especially against very low altitude anti-ship cruise missiles (ASCMs), should be improved. To achieve the required future air defense lethality, the JMSDF must optimize the resource allocation within a limited budget. Therefore, it is important to understand the essential elements of air defense lethality by the JMSDF Aegis destroyer in order to improve their operational effectiveness. In this study, a measure of effectiveness (MOE) for Aegis lethality against an ASCM attack is defined as 'a denial area at an acceptable risk.' Using this MOE, spread sheet lethality models based on Aegis weapons characteristics, target detection range, reaction time, and ASCM speed, are developed and used to study several alternative improvements to Aegis.http://archive.org/details/astudyofmeasures109457459Japanese Maritime Self Defense Force author

    From Mott insulator to ferromagnetic metal: a pressure study of Ca2_{2}RuO4_{4}

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    We show that the pressure-temperature phase diagram of the Mott insulator Ca2_{2}RuO4_{4} features a metal-insulator transition at 0.5GPa: at 300K from paramagnetic insulator to paramagnetic quasi-two-dimensional metal; at T≀T \leq 12K from antiferromagnetic insulator to ferromagnetic, highly anisotropic, three-dimensional metal. % We compare the metallic state to that of the structurally related p-wave superconductor Sr2_{2}RuO4_{4}, and discuss the importance of structural distortions, which are expected to couple strongly to pressure.Comment: 4 pages, 4figure

    Gemcitabine and S-1 Combination Chemotherapy in Patients with Advanced Biliary Tract Cancer: A Retrospective Study

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    Background:The aim of this study was to investigate the efficacy and safety of gemcitabine and S-1 combination chemotherapy in patients with advanced biliary tract cancer. Patients and Methods: A retrospective study was performed on 15 consecutive patients. Gemcitabine was administered intravenously at 1,000 mg/m2 on days 8 and 15. Oral S-1 (60 mg/m2 in 2 divided doses) was given daily for the first 2 weeks, followed by 1 week of rest. This 3-week course of treatment was repeated. The primary endpoint was response rate, and the secondary endpoints were overall survival, progression-free survival, and safety. Results: The overall response rate was 26.7%, and the disease control rate was 73.4%. The overall survival was 12.0 months (95% CI, 9.5–14.5 months), and the progression-free survival was 8.0 months (95% CI, 4.3–11.7 months). Adverse events of grade 3 or 4 occurred in 33.3%, and the major grade 3/4 toxicities were anemia (20.0%), leukopenia (13.3%), and anorexia (13.3%). Conclusion:Gemcitabine and S-1 combination chemotherapy is effective and safe in patients with advanced biliary tract cancer

    Crucial role of vinexin for keratinocyte migration in vitro and epidermal wound healing in vivo.

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    In the process of tissue injury and repair, epithelial cells rapidly migrate and form epithelial sheets. Vinexin is a cytoplasmic molecule of the integrin-containing cell adhesion complex localized at focal contacts in vitro. Here, we investigated the roles of vinexin in keratinocyte migration in vitro and wound healing in vivo. Vinexin knockdown using siRNA delayed migration of both HaCaT human keratinocytes and A431 epidermoid carcinoma cells in scratch assay but did not affect cell proliferation. Induction of cell migration by scratching the confluent monolayer culture of these cells activated both EGFR and ERK, and their inhibitors AG1478 and U0126 substantially suppressed scratch-induced keratinocyte migration. Vinexin knockdown in these cells inhibited the scratch-induced activation of EGFR, but not that of ERK, suggesting that vinexin promotes cell migration via activation of EGFR. We further generated vinexin (-/-) mice and isolated their keratinocytes. They similarly showed slow migration in scratch assay. Furthermore, vinexin (-/-) mice exhibited a delay in cutaneous wound healing in both the back skin and tail without affecting the proliferation of keratinocytes. Together, these results strongly suggest a crucial role of vinexin in keratinocyte migration in vitro and cutaneous wound healing in vivo

    Inhibitors of a Na⁺-pumping NADH-ubiquinone oxidoreductase play multiple roles to block enzyme function

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    The Na⁺-pumping NADH-ubiquinone (UQ) oxidoreductase (Na⁺-NQR) is present in the respiratory chain of many pathogenic bacteria and is thought to be a promising antibiotic target. Whereas many details of Na⁺-NQR structure and function are known, the mechanisms of action of potent inhibitors is not well-understood; elucidating the mechanisms would not only advance drug design strategies but might also provide insights on a terminal electron transfer from riboflavin to UQ. To this end, we performed photoaffinity labeling experiments using photoreactive derivatives of two known inhibitors, aurachin and korormicin, on isolated Vibrio cholerae Na⁺-NQR. The inhibitors labeled the cytoplasmic surface domain of the NqrB subunit including a protruding N-terminal stretch, which may be critical to regulate the UQ reaction in the adjacent NqrA subunit. The labeling was blocked by short-chain UQs such as ubiquinone-2. The photolabile group (2-aryl-5-carboxytetrazole (ACT)) of these inhibitors reacts with nucleophilic amino acids, so we tested mutations of nucleophilic residues in the labeled region of NqrB, such as Asp49 and Asp52 (to Ala), and observed moderate decreases in labeling yields, suggesting that these residues are involved in the interaction with ACT. We conclude that the inhibitors interfere with the UQ reaction in two ways: the first is blocking structural rearrangements at the cytoplasmic interface between NqrA and NqrB, and the second is the direct obstruction of UQ binding at this interfacial area. Unusual competitive behavior between the photoreactive inhibitors and various competitors corroborates our previous proposition that there may be two inhibitor binding sites in Na⁺-NQR
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