334 research outputs found

    Polars of Artin-Schreier curves

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    Submitted by Vitor Silverio Rodrigues ([email protected]) on 2014-05-27T11:18:09Z No. of bitstreams: 0Made available in DSpace on 2014-05-27T11:18:09Z (GMT). No. of bitstreams: 0 Previous issue date: 1996-12-01Universidade Federal Fluminense Depto. de Matemática Aplicada Campus do Valonguinho, R. São Paulo s/n, 24020-005 Niterói, RJDepartamento de Matemática IBILCE, R. Cristovão Colombo 2265, 15054-000 S. Jose do Rio Preto, SPDepartamento de Matemática IBILCE, R. Cristovão Colombo 2265, 15054-000 S. Jose do Rio Preto, S

    High-resolution reconstruction of late Pleistocene climate based on TOC content in a 54m sediment core drilled from Takano Formation, central Japan

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    The Takano Formation of late Pleistocene lacustrine sediment is distributed at the southern Nagano City. The TKN-2004 core, 53.88 m long, was taken at the central part or the basin, and is composed mostly or homogenous clayey silt. Age of the sediment was estimated from the relationship between radiometric ages and calibrated depths of DKP,Aso-4,K-Tz,Ata and Aso-2tephras, postulating that the sedimentation rate is constant.Paleoclimate from 169ka to 37ka was reconstructed on the basis of TOC content variation. The long-term TOC fluctuations are concordant with the SPECMAP curve. This result is supported by pollen composition. The short-term variations are similar to stadial-interstadial cycles in the Greenland ice cores, and most of warm peaks can be correlated with IS 9 to 25.長野市南部に分布する更新世後期の湖成層である高野層において,全層ボーリングを行い53.88mの連続したコア試料を得た.コア試料は,黒灰色ではぼ均質な粘土質シルト~シルトの層相を示し,多数のテフラ層を挟んでいる.これらのうち5つの広域指標テフラ(DKP,Aso-4,K-Tz, Ata,Aso-2)の放射年代値と補正深度を用いて年代モデルを作成した.高野層のTOC含有率の経年変動は,本コア試料中の花粉組成変化と同調しており,およそ169ka~37kaにおける数万年周期の長期の気候変動を示している.この変動はMIS 6-3前半における海洋酸素同位体比変動と同調しており,各ステージに対比される長期の温暖期・寒冷期が認識できた.また,数百~数千年周期の短期の寒暖変動も存在しており,これらは亜氷期-亜間氷期サイクルに相当すると考えられる.また,それらの温暖期の多くはIS9~25に対比される可能性がある.ArticleJournal of the Sedimentological Society of Japan. 64:37-41 (2007)journal articl

    Prominin-1 Modulates Rho/ROCK-Mediated Membrane Morphology and Calcium-Dependent Intracellular Chloride Flux

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    Membrane morphology is an important structural determinant as it reflects cellular functions. The pentaspan membrane protein Prominin-1 (Prom1/CD133) is known to be localised to protrusions and plays a pivotal role in migration and the determination of cellular morphology; however, the underlying mechanism of its action have been elusive. Here, we performed molecular characterisation of Prom1, focussing primarily on its effects on cell morphology. Overexpression of Prom1 in RPE-1 cells triggers multiple, long, cholesterol-enriched fibres, independently of actin and microtubule polymerisation. A five amino acid stretch located at the carboxyl cytosolic region is essential for fibre formation. The small GTPase Rho and its downstream Rho-associated coiled-coil-containing protein kinase (ROCK) are also essential for this process, and active Rho colocalises with Prom1 at the site of initialisation of fibre formation. In mouse embryonic fibroblast (MEF) cells we show that Prom1 is required for chloride ion efflux induced by calcium ion uptake, and demonstrate that fibre formation is closely associated with chloride efflux activity. Collectively, these findings suggest that Prom1 affects cell morphology and contributes to chloride conductance

    Paclitaxel and Sorafenib: The Effective Combination of Suppressing the Self-Renewal of Cancer Stem Cells

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    Combination therapy, which is a treatment modality combining two or more therapeutic agents, is considered a cornerstone of cancer therapy. The combination of anticancer drugs, of which functions are different from the other, enhances the efficiency compared to the monotherapy because it targets cancer cells in a synergistic or an additive manner. In this study, the combination of paclitaxel and sorafenib in low concentration was evaluated to target cancer stem cells, miPS-BT549cmP and miPS-Huh7cmP cells, developed from mouse induced pluripotent stem cells. The synergistic effect of paclitaxel and sorafenib on cancer stem cells was assessed by the inhibition of proliferation, self-renewal, colony formation, and differentiation. While the IC(50)values of paclitaxel and sorafenib were approximately ranging between 250 and 300 nM and between 6.5 and 8 mu M, respectively, IC(50)of paclitaxel reduced to 20 and 25 nM, which was not toxic in a single dose, in the presence of 1 mu M sorafenib, which was not toxic to the cells. Then, the synergistic effect was further assessed for the potential of self-renewal of cancer stem cells by sphere formation ability. As a result, 1 mu M of sorafenib significantly enhanced the effect of paclitaxel to suppress the number of spheres. Simultaneously, paclitaxel ranging in 1 to 4 nM significantly suppressed not only the colony formation but also the tube formation of the cancer stem cells in the presence of 1 mu M sorafenib. These results suggest the combination therapy of paclitaxel and sorafenib in low doses should be an attractive approach to target cancer stem cells with fewer side effects

    Nanostructured AgBr loaded TiO2: An efficient sunlight active photocatalyst for degradation of Reactive Red 120

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    The AgBr loaded TiO2 catalyst was prepared by a feasible approach with AgBr and tetraisopropyl orthotitanate and characterized by BET surface area measurement, diffuse reflectance spectra (DRS), scanning electron microscope (SEM), energy dispersive spectra (EDS), X-ray diffraction (XRD), transmission electron microscope (TEM) and atomic force microscope (AFM) analysis. The results of characterization reveal that AgBr loaded TiO2 has a nanostructure. Formation of the nanostructure in AgBr loaded TiO2 results in substantial shifting of the absorption edge of TiO2 to red and enhancement of visible light absorption. Electrochemical impedance spectroscopy measurements reveal that AgBr loaded TiO2 has a higher photoconductivity than prepared TiO2 due to higher separation efficiency of electron-hole pairs. Cyclic voltammetric studies reveal enhanced conductivity in AgBr loaded TiO2, which causes an increase in its photocatalytic activity. AgBr loaded TiO2 exhibited a higher photocatalytic activity than TiO2-P25 and prepared TiO2 in the photodegradation of Reactive Red 120 (RR 120)

    The Relationship between Oral Squamous Cell Carcinoma and Human Papillomavirus: A Meta-Analysis of a Chinese Population (1994–2011)

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    Background: Previous studies indicated that oral squamous cell carcinomas (OSCC) might be related to human papilloma virus (HPV) infection. However, up to now, there still lacks a large sample study to analyze the relationship between OSCC in a Chinese population and oral HPV infection. In the present study, we used a meta-analysis to evaluate the relationship of OSCC with HPV infection in a Chinese population. Methods: The reports on HPV and OSCC in a Chinese population published between January, 1994, and September, 2011 were retrieved via CNKI/WANFANG/OVID/MEDLINE databases. According to the inclusion criteria, we selected 18 eligible case-control studies. After testing the heterogeneity of the studies by the Cochran Q test, the meta-analyses for HPV and HPV16 were performed using the fixed effects model. Results: The overall positive rates of HPV and HPV16 in OSCC were 58.0 % (354/610; 95 % confidence interval [CI], 54.1–61.9) and 47.47 % (169/356; 95 % CI: 42.3–52.7), respectively; which were significantly higher than those in normal controls 10.44% (26/249; 95 % CI: 7.2–14.7) and 7.1 % (13/182; 95 % CI: 4.2–11.8). Quantitative meta-analysis revealed that, compared with normal controls, the combined odds ratios of OSCC with HPV or HPV16 infection were 12.7 (95 % CI: 8.0–20.0) and 9.0 (95% CI: 5.1–15.6), respectively. Both Begg’s test and funnel plots revealed that no publication bias was found in this present study (P.0.05)

    Preliminary examination of the efficacy and safety of a standardized chamomile extract for chronic primary insomnia: A randomized placebo-controlled pilot study

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    <p>Abstract</p> <p>Background</p> <p>Despite being the most commonly used herbal for sleep disorders, chamomile's (<it>Matricaria recutita</it>) efficacy and safety for treating chronic primary insomnia is unknown. We examined the preliminary efficacy and safety of chamomile for improving subjective sleep and daytime symptoms in patients with chronic insomnia.</p> <p>Methods</p> <p>We performed a randomized, double-blind, placebo-controlled pilot trial in 34 patients aged 18-65 years with DSM-IV primary insomnia for ≥ 6-months. Patients were randomized to 270 mg of chamomile twice daily or placebo for 28-days. The primary outcomes were sleep diary measures. Secondary outcomes included daytime symptoms, safety assessments, and effect size of these measures.</p> <p>Results</p> <p>There were no significant differences between groups in changes in sleep diary measures, including total sleep time (TST), sleep efficiency, sleep latency, wake after sleep onset (WASO), sleep quality, and number of awakenings. Chamomile did show modest advantage on daytime functioning, although these did not reach statistical significance. Effect sizes were generally small to moderate (Cohen's <it>d </it>≤ 0.20 to < 0.60) with sleep latency, night time awakenings, and Fatigue Severity Scale (FSS), having moderate effect sizes in favor of chamomile. However, TST demonstrated a moderate effect size in favor of placebo. There were no differences in adverse events reported by the chamomile group compared to placebo.</p> <p>Conclusion</p> <p>Chamomile could provide modest benefits of daytime functioning and mixed benefits on sleep diary measures relative to placebo in adults with chronic primary insomnia. However, further studies in select insomnia patients would be needed to investigate these conclusions.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov Identifier <a href="http://www.clinicaltrials.gov/ct2/show/NCT01286324">NCT01286324</a></p
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