125 research outputs found

    Anomalous small-angle X-ray scattering analyses on hierarchical structures of rubber-filler systems

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    The hierarchical structures of poly(styrene-ran-butadiene) (SBR) rubber/carbon black (CB) systems vulcanized with sulfur and ZnO have been clarified using anomalous small-angle X-ray scattering (ASAXS) near the Zn absorption edge. In the case of SBR/CB systems vulcanized with peroxide, it has been found previously that the hierarchical structures formed by CB consist of aggregates of primary particles and agglomerates of those aggregates with mass-fractal dimensions. However, to date the hierarchical structures in SBR/CB systems vulcanized with sulfur and ZnO have not been well investigated, despite being commonly used. This is because the strong scattering contrast of Zn prevents the quantitative analyses of the hierarchical structures of CB using X-ray scattering. In this study, the effects of Zn on the scattering intensity were eliminated and the structure factors of CB in SBR/CB systems were obtained using the ASAXS method. By extrapolating to the zero volume fraction of CB, the particle structure factor of the CB aggregates was estimated and it was found that the CB aggregates consist of closely packed CB primary particles. The presence of large particles of ZnO and particles of ZnS on the order of 10 nm in size is confirmed

    THE ANALYSIS OF RACE PACING IN ELITE COMPETITIVE LONG-DISTANCE SPEED SKATING

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    The purpose of this study was to investigate the characteristics of racing pattern adopted by elite male speed skaters in official 5000m race. Twenty-four male skaters, who participated at the World Single Distances Speed Skating Championships 2008, were recorded using video camera (60Hz). The top group (top12 ranked skaters) was significantly faster than the 2nd group (13th to 24th ranked skaters) from 350m line to the finishing line (

    Tribological properties of PTFE filled plants-derived semi-aromatic polyamide (PA10T) and GF reinforced PTFE/PA10T composites

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    For the purpose of developing the new engineering materials such as structural materials and tribomaterials based on plants-derived polymers, the tribological properties of polytetrafluoroethylene (PTFE) filled plants-derived semi-aromatic polyamide 10T (PA10T) composites and glass fiber (GF) reinforced PTFE/PA10T composites were investigated. PA10T is a kind of polyphthalamide (PPA, semi-aromatic polyamide) and biomass polymer made from plants-derived decamethylenediamine and coal-derived terephthalic acid. PTFE/PA10T and GF/PA10T/PTFE composites were melt-mixed by a twin screw extruder and injection-molded. Their mechanical properties such as tensile, Izod impact, and tribological properties were evaluated. Tribological properties were measured by a ring-on-plate type sliding wear tester under dry condition. Tribological properties of PA10T such as frictional coefficient, specific wear rate and limiting pv value improved with the addition of PTFE, although the mechanical properties such as tensile strength and tensile modulus decreased with PTFE. On the other hand, the frictional coefficient and specific wear rate of GF/PA10T/PTFE composites were higher than those of PTFE/PA10T composites, however limiting pv value and mechanical properties improved significantly with the filling of GF. It follows from these results that it may be possible to develop the new tribomaterials based on plants-derived polymer composites with sufficient balances between mechanical and tribological properties

    Large Magnetic-Field-Induced Strains in Sintered Chromium Tellurides

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    Sintered samples of Cr3Te4 and Cr2Te3 are found to show large strains accompanied by large volume changes under a magnetic field. In Cr3Te4, volume increases of deltaV/V = 500-1170 ppm by applying a magnetic field of 9 T are observed over the entire temperature range below 350 K. At room temperature, the deltaV/V value exceeds 1000 ppm, which is considerably larger than the maximum values reported for Cr-based magnets thus far and is comparable to the room-temperature value of forced-volume magnetostriction in invar alloys. Cr2Te3 show a large deltaV/V of 680 ppm when applying a magnetic field of 9 T at 200 K. Both samples display particularly large volume increases around the Curie temperature, where they also show negative thermal expansion due to microstructural effects, suggesting that the cooperation between anisotropic lattice deformation associated with the magnetic ordering and microstructural effects is essential for the manifestation of the large magnetic-field-induced volume changes.Comment: 6 pages, 6 figure

    漫画の中の英語医療語と背景文化

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    現代アメリカ英語における医療語や、そこから派生した表現を分析した。主に、Mike Peters の漫画 Mother Goose & Grimm を素材に、アメリカにおいて日常的に使用されたり、注目を集めたりしている医療に関わる英語を取り上げ、それらの語や表現を理解するために必要であると同時に、特に英語を母国語としない、または英語文化圏の外にいる者にとって非常に大きな障害となる、言語文化的背景の考察を行った

    英語商品名の言語文化的諸相

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    アメリカ英語における商品名とその特殊な用例をいくつか取り上げ、品詞転換や意味変化といった言語学的特徴、さらには他の語と複合的に用いられることで新たな表現として派生していることを明らかにした。同時に、それらの言語変化を可能にしているアメリカ文化という背景の存在を指摘し、言語と文化の関わりについての研究が重要であることを具体的に示した

    Balloon Enteroscopy-Assisted Endoscopic Retrograde Cholangiopancreatography for the Treatment of Common Bile Duct Stones in Patients with Roux-en-Y Gastrectomy: Outcomes and Factors Affecting Complete Stone Extraction

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    Background: Endoscopic retrograde cholangiopancreatography (ERCP) for extraction of common bile duct (CBD) stones in patients with Roux-en-Y gastrectomy (RYG) remains technically challenging. Methods: Seventy-nine RYG patients (median 79 years old) underwent short-type double-balloon enteroscopy-assisted ERCP (sDBE-ERCP) for CBD stones at three referral hospitals from 2011-2020. We retrospectively investigated the treatment outcomes and potential factors affecting complete stone extraction. Results: The initial success rates of reaching the papilla of Vater, biliary cannulation, and biliary intervention, including complete stone extraction or biliary stent placement, were 92%, 81%, and 78%, respectively. Of 57 patients with attempted stone extraction, complete stone extraction was successful in 74% for the first session and ultimately in 88%. The adverse events rate was 5%. The multivariate analysis indicated that the largest CBD diameter >= 14 mm (odds ratio (OR), 0.04; 95% confidence interval (CI), 0.01-0.58; p = 0.018) and retroflex position (OR, 6.43; 95% CI, 1.12-36.81; p = 0.037) were independent predictive factors affecting complete stone extraction achievement. Conclusions: Therapeutic sDBE-ERCP for CBD stones in a relatively elderly RYG cohort, was effective and safe. A larger CBD diameter negatively affected complete stone extraction, but using the retroflex position may be useful for achieving complete stone clearance

    Bevacizumab increases the sensitivity of olaparib to homologous recombination-proficient ovarian cancer by suppressing CRY1 via PI3K/AKT pathway

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    PARP inhibitors have changed the management of advanced high-grade epithelial ovarian cancer (EOC), especially homologous recombinant (HR)-deficient advanced high-grade EOC. However, the effect of PARP inhibitors on HR-proficient (HRP) EOC is limited. Thus, new therapeutic strategy for HRP EOC is desired. In recent clinical study, the combination of PARP inhibitors with anti-angiogenic agents improved therapeutic efficacy, even in HRP cases. These data suggested that anti-angiogenic agents might potentiate the response to PARP inhibitors in EOC cells. Here, we demonstrated that anti-angiogenic agents, bevacizumab and cediranib, increased the sensitivity of olaparib in HRP EOC cells by suppressing HR activity. Most of the γ-H2AX foci were co-localized with RAD51 foci in control cells. However, most of the RAD51 were decreased in the bevacizumab-treated cells. RNA sequencing showed that bevacizumab decreased the expression of CRY1 under DNA damage stress. CRY1 is one of the transcriptional coregulators associated with circadian rhythm and has recently been reported to regulate the expression of genes required for HR in cancer cells. We found that the anti-angiogenic agents suppressed the increase of CRY1 expression by inhibiting VEGF/VEGFR/PI3K pathway. The suppression of CRY1 expression resulted in decrease of HR activity. In addition, CRY1 inhibition also sensitized EOC cells to olaparib. These data suggested that anti-angiogenic agents and CRY1 inhibitors will be the promising candidate in the combination therapy with PARP inhibitors in HR-proficient EOC

    Importance of Second-look Endoscopy on an Empty Stomach for Finding Gastric Bezoars in Patients with Gastric Ulcers

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     Most gastric bezoars can be treated with endoscopic fragmentation combined with or without cola dissolution, whereas laparotomy or laparoscopic surgery is generally inevitable for small intestinal bezoars because they cause small bowel obstruction. Therefore, early diagnosis and management of gastric bezoars are necessary to prevent bezoar-induced ileus. To investigate the incidence of overlooked gastric bezoars during the initial esophagogastroduodenoscopy, we retrospectively reviewed the cases of 27 patients diagnosed with gastrointestinal bezoars. The bezoars were diagnosed using esophagogastroduodenoscopy (n=25), abdominal ultrasonography (n=1), and barium follow-through examination (n=1). Bezoars were overlooked in 9/25 patients (36.0%) during the initial endoscopy examination because the bezoars were covered with debris in the stomach. Of the 9 patients, 8 had concomitant gastric ulcers, and the other patient had gastric lymphoma. Although a computed tomography (CT) scan was performed before the second-look endoscopy in 8 of the 9 patients, the bezoars were mistaken as food debris on CT findings and were overlooked in these patients. In conclusion, gastric bezoars may not be discovered during the initial esophagogastroduodenoscopy and CT scan. In cases with debris in the stomach, second-look endoscopy is essential to detect bezoars

    Gray matter alterations in early and late relapsing-remitting multiple sclerosis evaluated with synthetic quantitative magnetic resonance imaging

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    Abstract: Extensive gray matter (GM) involvement has been demonstrated in multiple sclerosis (MS) patients. This study was aimed to identify GM alterations in relapsing-remitting MS (RRMS) patients using synthetic quantitative MRI (qMRI). We assessed myelin volume fraction (MVF) in each voxel on the basis of R1 and R2 relaxation rates and proton density in 14 early and 28 late (disease duration 5 years, respectively) RRMS patients, and 15 healthy controls (HCs). The MVF and myelin volumes of GM (GM-MyVol) were compared between groups using GM-based spatial statistics (GBSS) and the Kruskal-Wallis test, respectively. Correlations between MVF or GM-MyVol and disease duration or expanded disability status scale were also evaluated. RRMS patients showed a lower MVF than HCs, predominantly in the limbic and para-limbic areas, with more extensive areas noted in late RRMS patients. Late-RRMS patients had the smallest GM-MyVol (20.44 mL; early RRMS, 22.77 mL; HCs, 23.36 mL). Furthermore, the GM-MyVol in the RRMS group was inversely correlated with disease duration (r = -0.43, p = 0.005). In conclusion, the MVF and MyVol obtained by synthetic qMRI can be used to evaluate GM differences in RRMS patients
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