875 research outputs found

    Bis(2-methoxy­phenolato-κ2 O,O′)copper(II)

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    In the title compound, [Cu(C7H7O2)2], the asymmetric unit contains one and a half molecules with the central Cu(II) atoms situated on a general position and on a centre of inversion, respectively. Both Cu(II) atoms show a similar slightly distorted square-planar coordination, resulting from four O atoms of two 2-methoxyphenolate anions

    Occurrence and Biodegradation of Nonylphenol in the Environment

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    Nonylphenol (NP) is an ultimate degradation product of nonylphenol polyethoxylates (NPE) that is primarily used in cleaning and industrial processes. Its widespread use has led to the wide existence of NP in various environmental matrices, such as water, sediment, air and soil. NP can be decreased by biodegradation through the action of microorganisms under aerobic or anaerobic conditions. Half-lives of biodegradation ranged from a few days to almost one hundred days. The degradation rate for NP was influenced by temperature, pH and additions of yeast extracts, surfactants, aluminum sulfate, acetate, pyruvate, lactate, manganese dioxide, ferric chloride, sodium chloride, hydrogen peroxide, heavy metals, and phthalic acid esters. Although NP is present at low concentrations in the environment, as an endocrine disruptor the risks of long-term exposure to low concentrations remain largely unknown. This paper reviews the occurrence of NP in the environment and its aerobic and anaerobic biodegradation in natural environments and sewage treatment plants, which is essential for assessing the potential risk associated with low level exposure to NP and other endocrine disruptors

    A Stem Cell-Based Tool for Small Molecule Screening in Adipogenesis

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    Techniques for small molecule screening are widely used in biological mechanism study and drug discovery. Here, we reported a novel adipocyte differentiation assay for small molecule selection, based on human mesenchymal stem cells (hMSCs) transduced with fluorescence reporter gene driven by adipogenic specific promoter - adipocyte Protein 2 (aP2; also namely Fatty Acid Binding Protein 4, FABP4). During normal adipogenic induction as well as adipogenic inhibition by Ly294002, we confirmed that the intensity of green fluorescence protein corresponded well to the expression level of aP2 gene. Furthermore, this variation of green fluorescence protein intensity can be read simply through fluorescence spectrophotometer. By testing another two small molecules in adipogenesis –Troglitazone and CHIR99021, we proved that this is a simple and sensitive method, which could be applied in adipocyte biology, drug discovery and toxicological study in the future

    miR-103 Regulates Oxidative Stress by Targeting the BCL2/Adenovirus E1B 19 kDa Interacting Protein 3 in HUVECs

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    Oxidative stress plays a critical role in cardiovascular diseases. Salidroside, a glycoside from Rhodiola rosea, has been used as an antioxidative therapy for oxidative injury in cardiac diseases. However, the mechanism underlying its antioxidant effect needs to be elucidated. Treatment of HUVECs with H2O2 significantly decreased the expression of miR-103 in a dose- and time-dependent manner, whereas pretreatment with salidroside significantly inhibited this decrease. Subsequent analysis showed that overexpression of miR-103 abrogated cell activity and ROS production induced by H2O2. Bcl2/adenovirus E1B 19 kDa interacting protein 3 (BNIP3) was determined to be a novel miR-103 target in HUVECs. Interestingly, H2O2 treatment upregulated BNIP3 expression; in turn, this effect was inhibited by pretreatment with salidroside. Further studies confirmed that the knockdown of BNIP3 enhanced cell activity and suppressed the ROS production induced by H2O2. These results demonstrated for the first time that salidroside protects HUVECs in part by upregulating the expression of miR-103, which mediates BNIP3 downregulation and plays an important role in the cytoprotective actions

    Nicotine Causes Mitochondrial Dynamics Imbalance and Apoptosis Through ROS Mediated Mitophagy Impairment in Cardiomyocytes

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    Nicotine contained in traditional cigarettes, hookahs, and e-cigarettes is an important risk factor for cardiovascular disease. Our previous study showed that macroautophagic flux impairment occurred under nicotine stimulation. However, whether nicotine influences mitochondrial dynamics in neonatal rat ventricular myocytes (NRVMs) is unclear. The purpose of this study was to explore the effects and potential mechanism of nicotine on mitophagy, mitochondrial dynamics, apoptosis, and the relationship between these processes in NRVMs. Our results showed that nicotine exposure increased mitochondria-derived superoxide production, decreased mitochondrial membrane potential, and impaired PINK1/Parkin-mediated mitophagic flux in NRVMs. Interestingly, nicotine significantly promoted dynamin-related protein 1 (Drp1)-mediated mitochondrial fission and suppressed mitofusin (MFN)-mediated fusion, which was also observed in the bafilomycin A1-treated group. These results suggest that mitophagic flux impairment may contribute to Drp-1-mediated mitochondrial fission. Finally, nicotine caused excessive mitochondrial fission and contributed to apoptosis, which could be alleviated by mdivi-1, an inhibitor of Drp1. In addition to CTSB, as we previously reported, the enzyme activity of cathepsin L (CTSL) was also decreased in lysosomes after stimulation with nicotine, which may be the main cause of the hindered mitophagic flux induced by nicotine in NRVMs. Pretreatment with Torin 1, which is an inhibitor of mTOR, activated CTSL and ameliorated nicotine-induced mTOR activation and mitophagy impairment, decreased mitochondria-derived superoxide production, and blunted mitochondrial fission and apoptosis. Pretreatment with the ROS scavenger N-acetyl-cysteine (NAC) or inhibitors of p38 and JNK, which could also alleviate mitophagy impairment, exhibited similar effects as Torin1 on mitochondria. Taken together, our study demonstrated that nicotine treatment may lead to an increase in Drp1-mediated mitochondrial fission by blocking mitophagic flux by weakening the enzyme activity of CTSL and activating the ROS/p38/JNK signaling pathway. Excessive mitochondrial fission induced by nicotine ultimately leads to apoptosis. Torin1 restored the decreased CTSL enzyme activity by removing excessive ROS and alleviated the effects of nicotine on mitophagic flux, mitochondrial dynamics, and apoptosis. These results may provide new evidence on the relationship between mitophagic flux and mitochondrial dynamics and new perspectives on nicotine’s effects on mitochondrial dynamics in cardiomyocytes

    A multinode quantum network over a metropolitan area

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    Towards realizing the future quantum internet, a pivotal milestone entails the transition from two-node proof-of-principle experiments conducted in laboratories to comprehensive, multi-node setups on large scales. Here, we report on the debut implementation of a multi-node entanglement-based quantum network over a metropolitan area. We equipped three quantum nodes with atomic quantum memories and their telecom interfaces, and combined them into a scalable phase-stabilized architecture through a server node. We demonstrated heralded entanglement generation between two quantum nodes situated 12.5 km apart, and the storage of entanglement exceeding the round-trip communication time. We also showed the concurrent entanglement generation on three links. Our work provides a metropolitan-scale testbed for the evaluation and exploration of multi-node quantum network protocols and starts a new stage of quantum internet research.Comment: 21 pages in total, 4 figures and 1 table in the main text, 5 figures and 8 tables in the supplementary materia

    A simulation study on the measurement of D0-D0bar mixing parameter y at BES-III

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    We established a method on measuring the \dzdzb mixing parameter yy for BESIII experiment at the BEPCII e+ee^+e^- collider. In this method, the doubly tagged ψ(3770)D0D0\psi(3770) \to D^0 \overline{D^0} events, with one DD decays to CP-eigenstates and the other DD decays semileptonically, are used to reconstruct the signals. Since this analysis requires good e/πe/\pi separation, a likelihood approach, which combines the dE/dxdE/dx, time of flight and the electromagnetic shower detectors information, is used for particle identification. We estimate the sensitivity of the measurement of yy to be 0.007 based on a 20fb120fb^{-1} fully simulated MC sample.Comment: 6 pages, 7 figure

    Polycation-π Interactions Are a Driving Force for Molecular Recognition by an Intrinsically Disordered Oncoprotein Family

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    Molecular recognition by intrinsically disordered proteins (IDPs) commonly involves specific localized contacts and target-induced disorder to order transitions. However, some IDPs remain disordered in the bound state, a phenomenon coined "fuzziness", often characterized by IDP polyvalency, sequence-insensitivity and a dynamic ensemble of disordered bound-state conformations. Besides the above general features, specific biophysical models for fuzzy interactions are mostly lacking. The transcriptional activation domain of the Ewing's Sarcoma oncoprotein family (EAD) is an IDP that exhibits many features of fuzziness, with multiple EAD aromatic side chains driving molecular recognition. Considering the prevalent role of cation-π interactions at various protein-protein interfaces, we hypothesized that EAD-target binding involves polycation- π contacts between a disordered EAD and basic residues on the target. Herein we evaluated the polycation-π hypothesis via functional and theoretical interrogation of EAD variants. The experimental effects of a range of EAD sequence variations, including aromatic number, aromatic density and charge perturbations, all support the cation-π model. Moreover, the activity trends observed are well captured by a coarse-grained EAD chain model and a corresponding analytical model based on interaction between EAD aromatics and surface cations of a generic globular target. EAD-target binding, in the context of pathological Ewing's Sarcoma oncoproteins, is thus seen to be driven by a balance between EAD conformational entropy and favorable EAD-target cation-π contacts. Such a highly versatile mode of molecular recognition offers a general conceptual framework for promiscuous target recognition by polyvalent IDPs. © 2013 Song et al

    Study of J/ψppˉJ/\psi\to p\bar{p} and J/ψnnˉJ/\psi\to n\bar{n}

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    The decays J/ψppˉJ/\psi\to p\bar{p} and J/ψnnˉJ/\psi\to n\bar{n} have been investigated with a sample of 225.2 million J/ψJ/\psi events collected with the BESIII detector at the BEPCII e+ee^+e^- collider. The branching fractions are determined to be B(J/ψppˉ)=(2.112±0.004±0.031)×103\mathcal{B}(J/\psi\to p\bar{p})=(2.112\pm0.004\pm0.031)\times10^{-3} and B(J/ψnnˉ)=(2.07±0.01±0.17)×103\mathcal{B}(J/\psi\to n\bar{n})=(2.07\pm0.01\pm0.17)\times10^{-3}. Distributions of the angle θ\theta between the proton or anti-neutron and the beam direction are well described by the form 1+αcos2θ1+\alpha\cos^2\theta, and we find α=0.595±0.012±0.015\alpha=0.595\pm0.012\pm0.015 for J/ψppˉJ/\psi\to p\bar{p} and α=0.50±0.04±0.21\alpha=0.50\pm0.04\pm0.21 for J/ψnnˉJ/\psi\to n\bar{n}. Our branching-fraction results suggest a large phase angle between the strong and electromagnetic amplitudes describing the J/ψNNˉJ/\psi\to N\bar{N} decay.Comment: 16 pages, 13 figures, the 2nd version, submitted to PR
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