206 research outputs found

    Discovery of estrogen receptor α target genes and response elements in breast tumor cells

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    BACKGROUND: Estrogens and their receptors are important in human development, physiology and disease. In this study, we utilized an integrated genome-wide molecular and computational approach to characterize the interaction between the activated estrogen receptor (ER) and the regulatory elements of candidate target genes. RESULTS: Of around 19,000 genes surveyed in this study, we observed 137 ER-regulated genes in T-47D cells, of which only 89 were direct target genes. Meta-analysis of heterogeneous in vitro and in vivo datasets showed that the expression profiles in T-47D and MCF-7 cells are remarkably similar and overlap with genes differentially expressed between ER-positive and ER-negative tumors. Computational analysis revealed a significant enrichment of putative estrogen response elements (EREs) in the cis-regulatory regions of direct target genes. Chromatin immunoprecipitation confirmed ligand-dependent ER binding at the computationally predicted EREs in our highest ranked ER direct target genes, NRIP1, GREB1 and ABCA3. Wider examination of the cis-regulatory regions flanking the transcriptional start sites showed species conservation in mouse-human comparisons in only 6% of predicted EREs. CONCLUSIONS: Only a small core set of human genes, validated across experimental systems and closely associated with ER status in breast tumors, appear to be sufficient to induce ER effects in breast cancer cells. That cis-regulatory regions of these core ER target genes are poorly conserved suggests that different evolutionary mechanisms are operative at transcriptional control elements than at coding regions. These results predict that certain biological effects of estrogen signaling will differ between mouse and human to a larger extent than previously thought

    Graphene-Based Nanocomposites for Energy Storage

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    Since the first report of using micromechanical cleavage method to produce graphene sheets in 2004, graphene/graphene-based nanocomposites have attracted wide attention both for fundamental aspects as well as applications in advanced energy storage and conversion systems. In comparison to other materials, graphene-based nanostructured materials have unique 2D structure, high electronic mobility, exceptional electronic and thermal conductivities, excellent optical transmittance, good mechanical strength, and ultrahigh surface area. Therefore, they are considered as attractive materials for hydrogen (H2) storage and high-performance electrochemical energy storage devices, such as supercapacitors, rechargeable lithium (Li)-ion batteries, Li–sulfur batteries, Li–air batteries, sodium (Na)-ion batteries, Na–air batteries, zinc (Zn)–air batteries, and vanadium redox flow batteries (VRFB), etc., as they can improve the efficiency, capacity, gravimetric energy/power densities, and cycle life of these energy storage devices. In this article, recent progress reported on the synthesis and fabrication of graphene nanocomposite materials for applications in these aforementioned various energy storage systems is reviewed. Importantly, the prospects and future challenges in both scalable manufacturing and more energy storage-related applications are discussed

    Measurements of the branching fractions for BKγB \to K^{*}\gamma decays at Belle II

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    This paper reports a study of BKγB \to K^{*}\gamma decays using 62.8±0.662.8\pm 0.6 fb1^{-1} of data collected during 2019--2020 by the Belle II experiment at the SuperKEKB e+ee^{+}e^{-} asymmetric-energy collider, corresponding to (68.2±0.8)×106(68.2 \pm 0.8) \times 10^6 BBB\overline{B} events. We find 454±28454 \pm 28, 50±1050 \pm 10, 169±18169 \pm 18, and 160±17160 \pm 17 signal events in the decay modes B0K0[K+π]γB^{0} \to K^{*0}[K^{+}\pi^{-}]\gamma, B0K0[KS0π0]γB^{0} \to K^{*0}[K^0_{\rm S}\pi^{0}]\gamma, B+K+[K+π0]γB^{+} \to K^{*+}[K^{+}\pi^{0}]\gamma, and B+K+[K+π0]γB^{+} \to K^{*+}[K^{+}\pi^{0}]\gamma, respectively. The uncertainties quoted for the signal yield are statistical only. We report the branching fractions of these decays: B[B0K0[K+π]γ]=(4.5±0.3±0.2)×105,\mathcal{B} [B^{0} \to K^{*0}[K^{+}\pi^{-}]\gamma] = (4.5 \pm 0.3 \pm 0.2) \times 10^{-5}, B[B0K0[KS0π0]γ]=(4.4±0.9±0.6)×105,\mathcal{B} [B^{0} \to K^{*0}[K^0_{\rm S}\pi^{0}]\gamma] = (4.4 \pm 0.9 \pm 0.6) \times 10^{-5}, B[B+K+[K+π0]γ]=(5.0±0.5±0.4)×105, and\mathcal{B} [B^{+} \to K^{*+}[K^{+}\pi^{0}]\gamma] = (5.0 \pm 0.5 \pm 0.4)\times 10^{-5},\text{ and} B[B+K+[KS0π+]γ]=(5.4±0.6±0.4)×105,\mathcal{B} [B^{+} \to K^{*+}[K^0_{\rm S}\pi^{+}]\gamma] = (5.4 \pm 0.6 \pm 0.4) \times 10^{-5}, where the first uncertainty is statistical, and the second is systematic. The results are consistent with world-average values

    Measurement of the branching fraction for the decay BK(892)+B \to K^{\ast}(892)\ell^+\ell^- at Belle II

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    We report a measurement of the branching fraction of BK(892)+B \to K^{\ast}(892)\ell^+\ell^- decays, where +=μ+μ\ell^+\ell^- = \mu^+\mu^- or e+ee^+e^-, using electron-positron collisions recorded at an energy at or near the Υ(4S)\Upsilon(4S) mass and corresponding to an integrated luminosity of 189189 fb1^{-1}. The data was collected during 2019--2021 by the Belle II experiment at the SuperKEKB e+ee^{+}e^{-} asymmetric-energy collider. We reconstruct K(892)K^{\ast}(892) candidates in the K+πK^+\pi^-, KS0π+K_{S}^{0}\pi^+, and K+π0K^+\pi^0 final states. The signal yields with statistical uncertainties are 22±622\pm 6, 18±618 \pm 6, and 38±938 \pm 9 for the decays BK(892)μ+μB \to K^{\ast}(892)\mu^+\mu^-, BK(892)e+eB \to K^{\ast}(892)e^+e^-, and BK(892)+B \to K^{\ast}(892)\ell^+\ell^-, respectively. We measure the branching fractions of these decays for the entire range of the dilepton mass, excluding the very low mass region to suppress the BK(892)γ(e+e)B \to K^{\ast}(892)\gamma(\to e^+e^-) background and regions compatible with decays of charmonium resonances, to be \begin{equation} {\cal B}(B \to K^{\ast}(892)\mu^+\mu^-) = (1.19 \pm 0.31 ^{+0.08}_{-0.07}) \times 10^{-6}, {\cal B}(B \to K^{\ast}(892)e^+e^-) = (1.42 \pm 0.48 \pm 0.09)\times 10^{-6}, {\cal B}(B \to K^{\ast}(892)\ell^+\ell^-) = (1.25 \pm 0.30 ^{+0.08}_{-0.07}) \times 10^{-6}, \end{equation} where the first and second uncertainties are statistical and systematic, respectively. These results, limited by sample size, are the first measurements of BK(892)+B \to K^{\ast}(892)\ell^+\ell^- branching fractions from the Belle II experiment
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