396 research outputs found

    Measurement of CP-violation asymmetries in D0 to Ks pi+ pi-

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    We report a measurement of time-integrated CP-violation asymmetries in the resonant substructure of the three-body decay D0 to Ks pi+ pi- using CDF II data corresponding to 6.0 invfb of integrated luminosity from Tevatron ppbar collisions at sqrt(s) = 1.96 TeV. The charm mesons used in this analysis come from D*+(2010) to D0 pi+ and D*-(2010) to D0bar pi-, where the production flavor of the charm meson is determined by the charge of the accompanying pion. We apply a Dalitz-amplitude analysis for the description of the dynamic decay structure and use two complementary approaches, namely a full Dalitz-plot fit employing the isobar model for the contributing resonances and a model-independent bin-by-bin comparison of the D0 and D0bar Dalitz plots. We find no CP-violation effects and measure an asymmetry of ACP = (-0.05 +- 0.57 (stat) +- 0.54 (syst))% for the overall integrated CP-violation asymmetry, consistent with the standard model prediction.Comment: 15 page

    Quantum-Dot Light-Emitting Diodes with Nitrogen-Doped Carbon Nanodot Hole Transport and Electronic Energy Transfer Layer

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    Electroluminescence efficiency is crucial for the application of quantum-dot light-emitting diodes (QD-LEDs) in practical devices. We demonstrate that nitrogen-doped carbon nanodot (N-CD) interlayer improves electrical and luminescent properties of QD-LEDs. The N-CDs were prepared by solution-based bottom up synthesis and were inserted as a hole transport layer (HTL) between other multilayer HTL heterojunction and the red-QD layer. The QD-LEDs with N-CD interlayer represented superior electrical rectification and electroluminescent efficiency than those without the N-CD interlayer. The insertion of N-CD layer was found to provoke the Forster resonance energy transfer (FRET) from N-CD to QD layer, as confirmed by time-integrated and - resolved photoluminescence spectroscopy. Moreover, hole-only devices (HODs) with N-CD interlayer presented high hole transport capability, and ultraviolet photoelectron spectroscopy also revealed that the N-CD interlayer reduced the highest hole barrier height. Thus, more balanced carrier injection with sufficient hole carrier transport feasibly lead to the superior electrical and electroluminescent properties of the QD-LEDs with N-CD interlayer. We further studied effect of N-CD interlayer thickness on electrical and luminescent performances for high-brightness QD-LEDs. The ability of the N-CD interlayer to improve both the electrical and luminescent characteristics of the QD-LEDs would be readily exploited as an emerging photoactive material for high-efficiency optoelectronic devices.ope

    FOXA1 repression is associated with loss of BRCA1 and increased promoter methylation and chromatin silencing in breast cancer

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    FOXA1 expression correlates with the breast cancer luminal subtype and patient survival. RNA and protein analysis of a panel of breast cancer cell lines revealed that BRCA1 deficiency is associated with the downregulation of FOXA1 expression. Knockdown of BRCA1 resulted in the downregulation of FOXA1 expression and enhancement of FOXA1 promoter methylation in MCF-7 breast cancer cells, whereas the reconstitution of BRCA1 in Brca1-deficent mouse mammary epithelial cells (MMECs) promoted Foxa1 expression and methylation. These data suggest that BRCA1 suppresses FOXA1 hypermethylation and silencing. Consistently, the treatment of MMECs with the DNA methylation inhibitor 5-aza-2'-deoxycitydine induced Foxa1 mRNA expression. Furthermore, treatment with GSK126, an inhibitor of EZH2 methyltransferase activity, induced FOXA1 expression in BRCA1-deficient but not in BRCA1-reconstituted MMECs. Likewise, the depletion of EZH2 by small interfering RNA enhanced FOXA1 mRNA expression. Chromatin immunoprecipitation (ChIP) analysis demonstrated that BRCA1, EZH2, DNA methyltransferases (DNMT)1/3a/3b and H3K27me3 are recruited to the endogenous FOXA1 promoter, further supporting the hypothesis that these proteins interact to modulate FOXA1 methylation and repression. Further co-immunoprecipitation and ChIP analysis showed that both BRCA1 and DNMT3b form complexes with EZH2 but not with each other, consistent with the notion that BRCA1 binds to EZH2 and negatively regulates its methyltransferase activity. We also found that EZH2 promotes and BRCA1 impairs the deposit of the gene silencing histone mark H3K27me3 on the FOXA1 promoter. These associations were validated in a familial breast cancer patient cohort. Integrated analysis of the global gene methylation and expression profiles of a set of 33 familial breast tumours revealed that FOXA1 promoter methylation is inversely correlated with the transcriptional expression of FOXA1 and that BRCA1 mutation breast cancer is significantly associated with FOXA1 methylation and downregulation of FOXA1 expression, providing physiological evidence to our findings that FOXA1 expression is regulated by methylation and chromatin silencing and that BRCA1 maintains FOXA1 expression through suppressing FOXA1 gene methylation in breast cancer.Oncogene advance online publication, 22 December 2014; doi:10.1038/onc.2014.421.published_or_final_versio

    High Efficiency Colloidal Quantum Dot Infrared Light Emitting Diodes via Engineering at the Supra-Nanocrystalline Level

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    Colloidal quantum dot (CQD) light-emitting diodes (LEDs) deliver a compelling performance in the visible, yet infrared CQD LEDs underperform their visible-emitting counterparts, largely due to their low photoluminescence quantum efficiency. Here we employ a ternary blend of CQD thin film that comprises a binary host matrix that serves to electronically passivate as well as to cater for an efficient and balanced carrier supply to the emitting quantum dot species. In doing so, we report infrared PbS CQD LEDs with an external quantum efficiency of ~7.9% and a power conversion efficiency of ~9.3%, thanks to their very low density of trap states, on the order of 1014 cm−3, and very high photoluminescence quantum efficiency in electrically conductive quantum dot solids of more than 60%. When these blend devices operate as solar cells they deliver an open circuit voltage that approaches their radiative limit thanks to the synergistic effect of the reduced trap-state density and the density of state modification in the nanocomposite.Peer ReviewedPostprint (author's final draft

    Measurement of the WW and WZ production cross section using final states with a charged lepton and heavy-flavor jets in the full CDF Run II data set

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    Citation: Aaltonen, T., Amerio, S., Amidei, D., Anastassov, A., Annovi, A., Antos, J., . . . Zucchelli, S. (2016). Measurement of the WW and WZ production cross section using final states with a charged lepton and heavy-flavor jets in the full CDF Run II data set. Physical Review D - Particles, Fields, Gravitation and Cosmology, 94(3). doi:10.1103/PhysRevD.94.032008We present a measurement of the total WW and WZ production cross sections in pp collision at s=1.96 TeV, in a final state consistent with leptonic W boson decay and jets originating from heavy-flavor quarks from either a W or a Z boson decay. This analysis uses the full data set collected with the CDF II detector during Run II of the Tevatron collider, corresponding to an integrated luminosity of 9.4 fb-1. An analysis of the dijet mass spectrum provides 3.7? evidence of the summed production processes of either WW or WZ bosons with a measured total cross section of ?WW+WZ=13.7±3.9 pb. Independent measurements of the WW and WZ production cross sections are allowed by the different heavy-flavor decay patterns of the W and Z bosons and by the analysis of secondary-decay vertices reconstructed within heavy-flavor jets. The productions of WW and of WZ dibosons are independently seen with significances of 2.9? and 2.1?, respectively, with total cross sections of ?WW=9.4±4.2 pb and ?WZ=3.7-2.2+2.5 pb. The measurements are consistent with standard-model predictions. © 2016 American Physical Society

    ass and lifetime measurements of bottom and charm baryons in ppˉp\bar p collisions at $\sqrt{s}= 1.96 TeV

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    We report on mass and lifetime measurements of several ground state charmed and bottom baryons, using a data sample corresponding to 9.6 fb1\textrm{fb}^{-1} from ppˉp\bar p collisions at s=1.96\sqrt{s}=1.96 TeV, and recorded with the Collider Detector at Fermilab. Baryon candidates are reconstructed from data collected with an online event selection designed for the collection of long-lifetime heavy-flavor decay products and a second event selection designed to collect J/ψμ+μJ/\psi \rightarrow \mu^+ \, \mu^- candidates. First evidence for the process ΩbΩc0π\Omega_b^- \rightarrow \Omega_c^0 \, \pi^- is presented with a significance of 3.3σ3.3\sigma. We measure the following baryon masses: \begin{eqnarray} M(\Xi_c^{0}) = 2470.85\pm0.24(stat)\pm0.55(syst) \, MeV/c^2, \nonumber M(\Xi_c^{+}) = 2468.00\pm0.18(stat)\pm0.51(syst) \, MeV/c^2, \nonumber \\ M(\Lambda_b) = 5620.15\pm0.31(stat)\pm0.47(syst) \, MeV/c^2, \nonumber \\ M(\Xi_b^-) = 5793.4\pm1.8(stat)\pm0.7(syst) \, MeV/c^2, \nonumber \\ M(\Xi_b^0) = 5788.7\pm4.3(stat)\pm1.4(syst) \, MeV/c^2, \, and \nonumber \\ M(\Omega_b^-) = 6047.5\pm3.8(stat)\pm0.6(syst) \, MeV/c^2. \nonumber \end{eqnarray} The isospin splitting of the Ξb,0\Xi_b^{-,0} states is found to be M(Ξb)M(Ξb0)=4.7±4.7(stat)±0.7(syst)M(\Xi_b^-)-M(\Xi_b^0)=4.7\pm4.7(stat)\pm0.7(syst) MeV/c2c^2. The isospin splitting of the Ξc0,+\Xi_c^{0,+} states is found to be M(Ξc0)M(Ξc+)M(\Xi_c^0)-M(\Xi_c^+) = 2.85±0.30(stat)±0.04(syst)2.85\pm0.30(stat)\pm0.04(syst) MeV/c2c^2. The following lifetime measurements are made: \begin{eqnarray} \tau(\Lambda_b) = 1.565\pm0.035(stat)\pm0.020(syst) \, ps, \nonumber \\ \tau(\Xi_b^-) = 1.32\pm0.14(stat)\pm0.02(syst) \, ps, \nonumber \\ \tau(\Omega_b^-) = 1.66^{+0.53}_{-0.40}(stat)\pm0.02(syst) \, ps. \nonumber \end{eqnarray

    Antiviral kinetics of tenofovir alafenamide and tenofovir disoproxil fumarate over 24 weeks in women of childbearing potential with chronic HBV

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    Background/Purpose: Use of tenofovir disoproxil fumarate (TDF) improves patient outcomes in preventing mother-to-child transmission (pMTCT) of the hepatitis B virus (HBV) in mothers with chronic HBV and high viral loads. Given the lack of data for tenofovir alafenamide (TAF) in pMTCT, rates of early viral suppression with TAF and TDF were evaluated in women of childbearing potential (WOCBP) participating in 2 randomized, double-blind, Phase 3 studies in chronic HBV. Methods: In a patient subset meeting WOCBP criteria and with baseline HBV DNA >200,000 IU/mL, rates of viral suppression with TAF or TDF in achieving the target of HBV DNA <200,000 IU/mL at weeks 12 and 24 were assessed. Multivariate logistic regression was used to identify factors predictive of failure to suppress HBV DNA to the target level. Results: In 275 of 1298 (21%) patients meeting WOCBP criteria with high viral load, 93% and 96% had HBV DNA <200,000 IU/mL at weeks 12 and 24, respectively. Results for TAF (n = 194) vs TDF (n = 81) treatment were similar at weeks 12 and 24 (94% vs. 90% and 97% vs. 93%), respectively. High baseline HBV DNA level, genotype D infection, and prior interferon (week 24 only) were predictive of failure to achieve the target level. Both treatments were well tolerated with TAF showing less impact on renal and bone parameters. Conclusions: In WOCBP with high VL, no differences were found between TAF and TDF in reducing HBV DNA to levels associated with lower transmission risk. These data support ongoing studies of TAF for pMTCT.published_or_final_versio

    Measurement of sin2 θlept eff using eþe− pairs from γ=Z bosons produced in pp collisions at a center-of-momentum energy of 1.96 TeV

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    At the Fermilab Tevatron proton-antiproton (pp¯) collider, Drell-Yan lepton pairs are produced in the process pp¯→e+e−+X through an intermediate γ∗/Z boson. The forward-backward asymmetry in the polar-angle distribution of the e− as a function of the e+e−-pair mass is used to obtain sin2θlepteff, the effective leptonic determination of the electroweak-mixing parameter sin2θW. The measurement sample, recorded by the Collider Detector at Fermilab (CDF), corresponds to 9.4  fb−1 of integrated luminosity from pp¯ collisions at a center-of-momentum energy of 1.96 TeV, and is the full CDF Run II data set. The value of sin2θlepteff is found to be 0.23248±0.00053. The combination with the previous CDF measurement based on μ+μ− pairs yields sin2θlepteff=0.23221±0.00046. This result, when interpreted within the specified context of the standard model assuming sin2θW=1−M2W/M2Z and that the W- and Z-boson masses are on-shell, yields sin2θW=0.22400±0.00045, or equivalently a W-boson mass of 80.328±0.024  GeV/c2

    Nonlinear beam self-cleaning in a coupled cavity composite laser based on multimode fiber

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    We study a coupled cavity laser configuration where a passively Q-switched Nd:YAG microchip laser is combined with an extended cavity, including a doped multimode fiber. For appropriate coupling levels with the extended cavity, we observed that beam selfcleaning was induced in the multimode fiber thanks to nonlinear modal coupling, leading to a quasi-single mode laser output. In the regime of beam self-cleaning, laser pulse duration was reduced from 525 to 225 ps. We also observed a Q-switched mode-locked operation, where spatial self-cleaning was accompanied by far-detuned nonlinear frequency conversion in the active multimode fiber

    Seaweed consumption and prevalence of depressive symptoms during pregnancy in Japan: Baseline data from the Kyushu Okinawa Maternal and Child Health Study

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    BACKGROUND: Seaweed is a popular traditional food in Japan and is a rich source of bioactive metabolites. The neuroprotective properties of seaweed have attracted attention; to date, however, there has been no epidemiological evidence regarding the relationship between seaweed consumption and depression. The current cross-sectional study investigated the association between seaweed consumption and depressive symptoms during pregnancy in Japan. METHODS: Study subjects were 1745 pregnant women. Depressive symptoms were defined as present when subjects had a Center for Epidemiologic Studies Depression Scale score of 16 or higher. Dietary consumption during the preceding month was assessed using a self-administered diet history questionnaire. Adjustment was made for age; gestation; region of residence; number of children; family structure; history of depression; family history of depression; smoking; secondhand smoke exposure at home and at work; job type; household income; education; body mass index; and intake of fish and yogurt. RESULTS: The prevalence of depressive symptoms during pregnancy was 19.3%. After adjustment for possible dietary and non-dietary confounding factors, higher seaweed consumption was independently associated with a lower prevalence of depressive symptoms during pregnancy: the adjusted odds ratios (95% confidence intervals) for depressive symptoms during pregnancy in the first, second, third, and fourth quartiles of seaweed consumption were 1 (reference), 0.72 (0.51 − 1.004), 0.71 (0.50 − 1.01), and 0.68 (0.47 − 0.96), respectively (P for trend = 0.03). CONCLUSIONS: The present results suggest that seaweed consumption may be inversely associated with the prevalence of depressive symptoms during pregnancy in Japanese women
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