100 research outputs found

    The Type Ia supernovae rate with Subaru/XMM-Newton Deep Survey

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    We present measurements of the rates of high-redshift Type Ia supernovae derived from the Subaru/XMM-Newton Deep Survey (SXDS). We carried out repeat deep imaging observations with Suprime-Cam on the Subaru Telescope, and detected 1040 variable objects over 0.918 deg2^2 in the Subaru/XMM-Newton Deep Field. From the imaging observations, light curves in the observed ii'-band are constructed for all objects, and we fit the observed light curves with template light curves. Out of the 1040 variable objects detected by the SXDS, 39 objects over the redshift range 0.2<z<1.40.2 < z < 1.4 are classified as Type Ia supernovae using the light curves. These are among the most distant SN Ia rate measurements to date. We find that the Type Ia supernova rate increase up to z0.8z \sim 0.8 and may then flatten at higher redshift. The rates can be fitted by a simple power law, rV(z)=r0(1+z)αr_V(z)=r_0(1+z)^\alpha with r0=0.200.16+0.52r_0=0.20^{+0.52}_{-0.16}(stat.)0.07+0.26^{+0.26}_{-0.07}(syst.)×104yr1Mpc3\times 10^{-4} {\rm yr}^{-1}{\rm Mpc}^{-3}, and α=2.041.96+1.84\alpha=2.04^{+1.84}_{-1.96}(stat.)0.86+2.11^{+2.11}_{-0.86}(syst.).Comment: 21 pages, 16 figures, accepted to PAS

    Self-renewal and chemotherapy resistance of p75NTR positive cells in esophageal squamous cell carcinomas

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    <p>Abstract</p> <p>Background</p> <p>p75<sup>NTR </sup>has been used to isolate esophageal and corneal epithelial stem cells. In the present study, we investigated the expression of p75<sup>NTR </sup>in esophageal squamous cell carcinoma (ESCC) and explored the biological properties of p75<sup>NTR+ </sup>cells.</p> <p>Methods</p> <p>p75<sup>NTR </sup>expression in ESCC was assessed by immunohistochemistry. p75<sup>NTR+ </sup>and p75<sup>NTR- </sup>cells of 4 ESCC cell lines were separated by fluorescence-activated cell sorting. Differentially expressed genes between p75<sup>NTR+ </sup>and p75<sup>NTR- </sup>cells were determined by real-time quantitative reverse transcription-PCR. Sphere formation assay, DDP sensitivity assay, <sup>64</sup>copper accumulation assay and tumorigenicity analysis were performed to determine the capacity of self-renewal, chemotherapy resistance and tumorigenicity of p75<sup>NTR+ </sup>cells.</p> <p>Results</p> <p>In ESCC specimens, p75<sup>NTR </sup>was found mainly confined to immature cells and absent in cells undergoing terminal differentiation. The percentage of p75<sup>NTR+ </sup>cells was 1.6%–3.7% in Eca109 and 3 newly established ESCC cell lines. The expression of Bmi-1, which is associated with self-renewal of stem cells, was significantly higher in p75<sup>NTR+ </sup>cells. p63, a marker identified in keratinocyte stem cells, was confined mainly to p75<sup>NTR+ </sup>cells. The expression of CTR1, which is associated with cisplatin (DDP)-resistance, was significantly decreased in p75<sup>NTR+ </sup>cells. Expression levels of differentiation markers, such as involucrin, cytokeratin 13, β1-integrin and β4-integrin, were lower in p75<sup>NTR+ </sup>cells. In addition, p75<sup>NTR+ </sup>cells generated both p75<sup>NTR+ </sup>and p75<sup>NTR- </sup>cells, and formed nonadherent spherical clusters in serum-free medium supplemented with growth factors. Furthermore, p75<sup>NTR+ </sup>cells were found to be more resistant to DDP and exhibited lower <sup>64</sup>copper accumulation than p75<sup>NTR- </sup>cells.</p> <p>Conclusion</p> <p>Our results demonstrated that p75<sup>NTR+ </sup>cells possess some characteristics of CSCs, namely, self-renewal and chemotherapy resistance. Chemotherapy resistance of p75<sup>NTR+ </sup>cells may probably be attributable to decreased expression of CTR1.</p

    Fermi Large Area Telescope Constraints on the Gamma-ray Opacity of the Universe

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    The Extragalactic Background Light (EBL) includes photons with wavelengths from ultraviolet to infrared, which are effective at attenuating gamma rays with energy above ~10 GeV during propagation from sources at cosmological distances. This results in a redshift- and energy-dependent attenuation of the gamma-ray flux of extragalactic sources such as blazars and Gamma-Ray Bursts (GRBs). The Large Area Telescope onboard Fermi detects a sample of gamma-ray blazars with redshift up to z~3, and GRBs with redshift up to z~4.3. Using photons above 10 GeV collected by Fermi over more than one year of observations for these sources, we investigate the effect of gamma-ray flux attenuation by the EBL. We place upper limits on the gamma-ray opacity of the Universe at various energies and redshifts, and compare this with predictions from well-known EBL models. We find that an EBL intensity in the optical-ultraviolet wavelengths as great as predicted by the "baseline" model of Stecker et al. (2006) can be ruled out with high confidence.Comment: 42 pages, 12 figures, accepted version (24 Aug.2010) for publication in ApJ; Contact authors: A. Bouvier, A. Chen, S. Raino, S. Razzaque, A. Reimer, L.C. Reye

    Angiotensin-Converting Enzyme (ACE) Gene Insertion/Deletion Polymorphism and ACE Inhibitor-Related Cough: A Meta-Analysis

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    Objective: An insertion/deletion (I/D) variant in the angiotensin-converting enzyme (ACE) gene was associated with ACE inhibitor (ACEI)-related cough in previous studies. However, the results were inconsistent. Our objective was to assess the relationship between the ACE I/D polymorphism and ACEI-related cough by meta-analysis and to summarize all studies that are related to ACE I/D polymorphism and ACEI-cough and make a summary conclusion to provide reference for the researchers who attempt to conduct such a study. Methods: Databases including PubMed, EMbase, Cochrane Library, and China National Knowledge Infrastructure, were searched for genetic association studies. Data were extracted by two independent authors and pooled odds ratio (OR) with 95% confidence interval (CI) was calculated. Metaregression and subgroup analyses were performed to identify the source of heterogeneity. Results: Eleven trials, including 906 cases (ACEI-related cough) and 1,175 controls, were reviewed in the present meta-analysis. The random effects pooled OR was 1.16 (95% CI: 0.78-1.74, p = 0.46) in the dominant model and 1.61 (95% CI: 1.18-2.20, p = 0.003) in the recessive model. Heterogeneity was found among and within studies. Metaregression indicated that the effect size was positively associated with age and negatively associated with follow-up duration of ACEI treatment. Subgroup analysis revealed a significant association between ACE I/D polymorphism and ACEI-related cough in studies with mean age >60 y, but not in studies with mean age 2 mo or in studies in Caucasians. No heterogeneity was detected in these two subgroups. Conclusions: Synthesis of the available evidence supports ACE I/D polymorphism as an age-dependent predictor for risk of ACEI-related cough

    Bioinorganic Chemistry of Alzheimer’s Disease

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    The IASLC Lung Cancer Staging Project: A Renewed Call to Participation

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    Over the past two decades, the International Association for the Study of Lung Cancer (IASLC) Staging Project has been a steady source of evidence-based recommendations for the TNM classification for lung cancer published by the Union for International Cancer Control and the American Joint Committee on Cancer. The Staging and Prognostic Factors Committee of the IASLC is now issuing a call for participation in the next phase of the project, which is designed to inform the ninth edition of the TNM classification for lung cancer. Following the case recruitment model for the eighth edition database, volunteer site participants are asked to submit data on patients whose lung cancer was diagnosed between January 1, 2011, and December 31, 2019, to the project by means of a secure, electronic data capture system provided by Cancer Research And Biostatistics in Seattle, Washington. Alternatively, participants may transfer existing data sets. The continued success of the IASLC Staging Project in achieving its objectives will depend on the extent of international participation, the degree to which cases are entered directly into the electronic data capture system, and how closely externally submitted cases conform to the data elements for the project

    Search for Supersymmetry with Gauge-Mediated Breaking in Diphoton Events with Missing Transverse Energy at CDF II

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    accepted to Phys. Rev. LettWe present the results of a search for supersymmetry with gauge-mediated breaking and \NONE\to\gamma\Gravitino in the γγ\gamma\gamma+missing transverse energy final state. In 2.6±\pm0.2 \invfb of ppˉp{\bar p} collisions at s\sqrt{s}==1.96 TeV recorded by the CDF II detector we observe no candidate events, consistent with a standard model background expectation of 1.4±\pm0.4 events. We set limits on the cross section at the 95% C.L. and place the world's best limit of 149\gevc on the \none mass at τχ~10\tau_{\tilde{\chi}_1^0}$We present the results of a search for supersymmetry with gauge-mediated breaking and χ˜10→γG˜ in the γγ+missing transverse energy final state. In 2.6±0.2  fb-1 of pp̅ collisions at √s=1.96  TeV recorded by the CDF II detector we observe no candidate events, consistent with a standard model background expectation of 1.4±0.4 events. We set limits on the cross section at the 95% C.L. and place the world’s best limit of 149  GeV/c2 on the χ˜10 mass at τχ˜10≪1  ns. We also exclude regions in the χ˜10 mass-lifetime plane for τχ˜10≲2  ns.Peer reviewe

    Measurements of branching fraction ratios and CP asymmetries in B+/- ->D_CP K+/- decays in hadron collisions

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    We reconstruct B+/- -> D K+/- decays in a data sample collected by the CDF II detector at the Tevatron collider corresponding to 1 fb-1 of integrated luminosity. We select decay modes where the D meson decays to either K- pi+ (flavor eigenstate) or K- K+, pi- pi+ (CP-even eigenstates), and measure the direct CP asymmetry A_CP+ = 0.39 +/- 0.17(stat) +/- 0.04(syst), and the double ratio of CP-even to flavor eigenstate branching fractions R_CP+ = 1.30 +/- 0.24(stat) +/- 0.12(syst). These measurements will improve the determination of the CKM angle gamma. They are performed here for the first time using data from hadron collisions.We reconstruct B±→DK± decays in a data sample collected by the CDF II detector at the Tevatron collider corresponding to 1  fb-1 of integrated luminosity. We select decay modes where the D meson decays to either K-π+ (flavor eigenstate) or K-K+, π-π+ (CP-even eigenstates), and measure the direct CP asymmetry ACP+=0.39±0.17(stat)±0.04(syst), and the double ratio of CP-even to flavor eigenstate branching fractions RCP+=1.30±0.24(stat)±0.12(syst). These measurements will improve the determination of the Cabibbo-Kobayashi-Maskawa angle γ. They are performed here for the first time using data from hadron collisions.Peer reviewe

    Inclusive Search for Standard Model Higgs Boson Production in the WW Decay Channel using the CDF II Detector

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    We present a search for standard model (SM) Higgs boson production using ppbar collision data at sqrt(s) = 1.96 TeV, collected with the CDF II detector and corresponding to an integrated luminosity of 4.8 fb-1. We search for Higgs bosons produced in all processes with a significant production rate and decaying to two W bosons. We find no evidence for SM Higgs boson production and place upper limits at the 95% confidence level on the SM production cross section (sigma(H)) for values of the Higgs boson mass (m_H) in the range from 110 to 200 GeV. These limits are the most stringent for m_H > 130 GeV and are 1.29 above the predicted value of sigma(H) for mH = 165 GeV.We present a search for standard model (SM) Higgs boson production using pp̅ collision data at √s=1.96  TeV, collected with the CDF II detector and corresponding to an integrated luminosity of 4.8  fb-1. We search for Higgs bosons produced in all processes with a significant production rate and decaying to two W bosons. We find no evidence for SM Higgs boson production and place upper limits at the 95% confidence level on the SM production cross section (σH) for values of the Higgs boson mass (mH) in the range from 110 to 200 GeV. These limits are the most stringent for mH>130  GeV and are 1.29 above the predicted value of σH for mH=165  GeV.Peer reviewe
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