1,127 research outputs found

    Knockdown of stem cell regulator Oct4A in ovarian cancer reveals cellular reprogramming associated with key regulators of cytoskeleton-extracellular matrix remodelling

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    Oct4A is a master regulator of self-renewal and pluripotency in embryonic stem cells. It is a well-established marker for cancer stem cell (CSC) in malignancies. Recently, using a loss of function studies, we have demonstrated key roles for Oct4A in tumor cell survival, metastasis and chemoresistance in in vitro and in vivo models of ovarian cancer. In an effort to understand the regulatory role of Oct4A in tumor biology, we employed the use of an ovarian cancer shRNA Oct4A knockdown cell line (HEY Oct4A KD) and a global mass spectrometry (MS)-based proteomic analysis to investigate novel biological targets of Oct4A in HEY samples (cell lysates, secretomes and mouse tumor xenografts). Based on significant differential expression, pathway and protein network analyses, and comprehensive literature search we identified key proteins involved with biologically relevant functions of Oct4A in tumor biology. Across all preparations of HEY Oct4A KD samples significant alterations in protein networks associated with cytoskeleton, extracellular matrix (ECM), proliferation, adhesion, metabolism, epithelial-mesenchymal transition (EMT), cancer stem cells (CSCs) and drug resistance was observed. This comprehensive proteomics study for the first time presents the Oct4A associated proteome and expands our understanding on the biological role of this stem cell regulator in carcinomas

    Search for CP Violation in the Decay Z -> b (b bar) g

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    About three million hadronic decays of the Z collected by ALEPH in the years 1991-1994 are used to search for anomalous CP violation beyond the Standard Model in the decay Z -> b \bar{b} g. The study is performed by analyzing angular correlations between the two quarks and the gluon in three-jet events and by measuring the differential two-jet rate. No signal of CP violation is found. For the combinations of anomalous CP violating couplings, h^b=h^AbgVbh^VbgAb{\hat{h}}_b = {\hat{h}}_{Ab}g_{Vb}-{\hat{h}}_{Vb}g_{Ab} and hb=h^Vb2+h^Ab2h^{\ast}_b = \sqrt{\hat{h}_{Vb}^{2}+\hat{h}_{Ab}^{2}}, limits of \hat{h}_b < 0.59and and h^{\ast}_{b} < 3.02$ are given at 95\% CL.Comment: 8 pages, 1 postscript figure, uses here.sty, epsfig.st

    Observation of two new Ξb\Xi_b^- baryon resonances

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    Two structures are observed close to the kinematic threshold in the Ξb0π\Xi_b^0 \pi^- mass spectrum in a sample of proton-proton collision data, corresponding to an integrated luminosity of 3.0 fb1^{-1} recorded by the LHCb experiment. In the quark model, two baryonic resonances with quark content bdsbds are expected in this mass region: the spin-parity JP=12+J^P = \frac{1}{2}^+ and JP=32+J^P=\frac{3}{2}^+ states, denoted Ξb\Xi_b^{\prime -} and Ξb\Xi_b^{*-}. Interpreting the structures as these resonances, we measure the mass differences and the width of the heavier state to be m(Ξb)m(Ξb0)m(π)=3.653±0.018±0.006m(\Xi_b^{\prime -}) - m(\Xi_b^0) - m(\pi^{-}) = 3.653 \pm 0.018 \pm 0.006 MeV/c2/c^2, m(Ξb)m(Ξb0)m(π)=23.96±0.12±0.06m(\Xi_b^{*-}) - m(\Xi_b^0) - m(\pi^{-}) = 23.96 \pm 0.12 \pm 0.06 MeV/c2/c^2, Γ(Ξb)=1.65±0.31±0.10\Gamma(\Xi_b^{*-}) = 1.65 \pm 0.31 \pm 0.10 MeV, where the first and second uncertainties are statistical and systematic, respectively. The width of the lighter state is consistent with zero, and we place an upper limit of Γ(Ξb)<0.08\Gamma(\Xi_b^{\prime -}) < 0.08 MeV at 95% confidence level. Relative production rates of these states are also reported.Comment: 17 pages, 2 figure

    Observation of associated production of a ZZ boson with a DD meson in the~forward region

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    A search for associated production of a ZZ boson with an open charm meson is presented using a data sample, corresponding to an integrated luminosity of 1.0fb1.0\,\mathrm{fb}^{-`} of proton--proton collisions at a centre-of-mass energy of 7\,TeV, collected by the LHCb experiment. %% Seven candidate events for associated production of a ZZ boson with a D0D^0 meson and four candidate events for a ZZ boson with a D+D^+ meson are observed with a combined significance of 5.1standard deviations. The production cross-sections in the forward region are measured to be σZμ+μ ⁣,D0=2.50±1.12±0.22pb\sigma_{Z\rightarrow\mu^+\mu^-\!,D^0} = 2.50\pm1.12\pm0.22pb σZμ+μ ⁣,D+=0.44±0.23±0.03pb,\sigma_{Z\rightarrow\mu^+\mu^-\!,D^+} = 0.44\pm0.23\pm0.03pb, where the first uncertainty is statistical and the second systematic.Comment: 18 pages, 2 figure

    Measurements of the B+B^+, B0B^0, Bs0B_s^0 meson and Λb0\Lambda_b^0 baryon lifetimes

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    Measurements of bb-hadron lifetimes are reported using pppp collision data, corresponding to an integrated luminosity of 1.0fb1^{-1}, collected by the LHCb detector at a centre-of-mass energy of 77Tev. Using the exclusive decays B+J/ψK+B^+\to J/\psi K^+, B0J/ψK(892)0B^0\to J/\psi K^*(892)^0, B0J/ψKS0B^0\to J/\psi K^0_{\rm S}, Λb0J/ψΛ\Lambda_b^0\to J/\psi \Lambda and Bs0J/ψϕB^0_s\to J/\psi \phi the average decay times in these modes are measured to be τB+J/ψK+\tau_{B^+\to J/\psi K^+} = 1.637±1.637 \pm 0.004 ±\pm 0.003 ps, τB0J/ψK(892)0\tau_{B^0\to J/\psi K^*(892)^0} = 1.524±1.524 \pm 0.006 ±\pm 0.004 ps, τB0J/ψKS0\tau_{B^0\to J/\psi K^0_{\rm S}} = 1.499±1.499 \pm 0.013 ±\pm 0.005 ps, τΛb0J/ψΛ\tau_{\Lambda_b^0\to J/\psi \Lambda} = 1.415±1.415 \pm 0.027 ±\pm 0.006 ps and τBs0J/ψϕ\tau_{B^0_s\to J/\psi \phi} = 1.480±1.480 \pm 0.011 ±\pm 0.005 ps, where the first uncertainty is statistical and the second is systematic. These represent the most precise lifetime measurements in these decay modes. In addition, ratios of these lifetimes, and the ratio of the decay-width difference, ΔΓd\Delta\Gamma_d, to the average width, Γd\Gamma_d, in the B0B^0 system, ΔΓd/Γd=0.044±0.025±0.011\Delta \Gamma_d/\Gamma_d = -0.044 \pm 0.025 \pm 0.011, are reported. All quantities are found to be consistent with Standard Model expectations.Comment: 28 pages, 4 figures. Updated reference

    Observation of the decay BcJ/ψK+Kπ+B_c \rightarrow J/\psi K^+ K^- \pi^+

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    The decay BcJ/ψK+Kπ+B_c\rightarrow J/\psi K^+ K^- \pi^+ is observed for the first time, using proton-proton collisions collected with the LHCb detector corresponding to an integrated luminosity of 3fb1^{-1}. A signal yield of 78±1478\pm14 decays is reported with a significance of 6.2 standard deviations. The ratio of the branching fraction of \B_c \rightarrow J/\psi K^+ K^- \pi^+ decays to that of BcJ/ψπ+B_c \rightarrow J/\psi \pi^+ decays is measured to be 0.53±0.10±0.050.53\pm 0.10\pm0.05, where the first uncertainty is statistical and the second is systematic.Comment: 18 pages, 2 figure

    Observation of the decay B+c→Bºsπ+

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    The result of a search for the decay B+c→Bºsπ+ is presented, using the Bºs→Ds-π+ and Bºs→J/ψϕ channels. The analysis is based on a data sample of pp collisions collected with the LHCb detector, corresponding to an integrated luminosity of 1  fb-1 taken at a center-of-mass energy of 7 TeV, and 2  fb-1 taken at 8 TeV. The decay B+c→Bºsπ+ is observed with significance in excess of 5 standard deviations independently in both decay channels. The measured product of the ratio of cross sections and branching fraction is [σ(Bc+)/σ(Bºs)]×B(Bc+→Bºsπ+)=[2.37±0.31 (stat)±0.11 (syst)-0.13+0.17(τBc+)]×10-3, in the pseudorapidity range 2<η(B)<5, where the first uncertainty is statistical, the second is systematic, and the third is due to the uncertainty on the Bc+ lifetime. This is the first observation of a B meson decaying to another B meson via the weak interaction

    Precision measurement of CPCP violation in Bs0J/ψK+KB_s^0 \to J/\psi K^+K^- decays

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    The time-dependent CPCP asymmetry in Bs0J/ψK+KB_s^0 \to J/\psi K^+K^- decays is measured using pppp collision data, corresponding to an integrated luminosity of 3.03.0fb1^{-1}, collected with the LHCb detector at centre-of-mass energies of 77 and 88TeV. In a sample of 96 000 Bs0J/ψK+KB_s^0 \to J/\psi K^+K^- decays, the CPCP-violating phase ϕs\phi_s is measured, as well as the decay widths ΓL\Gamma_{L} and ΓH\Gamma_{H} of the light and heavy mass eigenstates of the Bs0Bˉs0B_s^0-\bar{B}_s^0 system. The values obtained are ϕs=0.058±0.049±0.006\phi_s = -0.058 \pm 0.049 \pm 0.006 rad, Γs(ΓL+ΓH)/2=0.6603±0.0027±0.0015\Gamma_s \equiv (\Gamma_{L}+\Gamma_{H})/2 = 0.6603 \pm 0.0027 \pm 0.0015ps1^{-1}, andΔΓsΓLΓH=0.0805±0.0091±0.0032\Delta\Gamma_s \equiv \Gamma_{L} - \Gamma_{H} = 0.0805 \pm 0.0091 \pm 0.0032ps1^{-1}, where the first uncertainty is statistical and the second systematic. These are the most precise single measurements of those quantities to date. A combined analysis with Bs0J/ψπ+πB_s^{0} \to J/\psi \pi^+\pi^- decays gives ϕs=0.010±0.039\phi_s = -0.010 \pm 0.039 rad. All measurements are in agreement with the Standard Model predictions. For the first time the phase ϕs\phi_s is measured independently for each polarisation state of the K+KK^+K^- system and shows no evidence for polarisation dependence.Comment: 6 figure
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