227 research outputs found

    Tanshinone IIA suppresses fibrosis induced by high glucose conditions in HK-2 cells via inhibition of extracellular matrix deposition, reduction of oxidative stress, and inhibition of epithelial to mesenchymal transition

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    Purpose: To investigate the anti-fibrotic effects of tanshinone IIA (TS) on renal tubular epithelial cells (HK-2 cells) under high glucose conditions and their related molecular mechanism(s) of action.Methods: After treatment with TS (6 μg/mL) for 24 h, the morphology of HK-2 cells stimulated by high glucose was observed under the microscope. Additionally, potential mechanisms related to the antifibrosis effects of TS were evaluated using western blotting assay and quantitative real time PCR (qRTPCR), including transforming growth factor (TGF) β1, α-smooth muscle actin (α-SMA), heme oxygenase 1 (HO-1), laminin (LN), fibronectin (FN), and E-cadherin (E-cad).Results: A high-glucose culture environment induced fibrosis of HK-2 cells, as indicated by changes in cell morphology. The anti-fibrotic effects of TS were mainly associated with a decrease in the expression levels of TGF-β1, α-SMA and LN, while the expression of E-cad increased. These resultsalso revealed that TS increased the expressions of HO-1.Conclusion: The findings suggest that TS suppresses fibrosis caused by high glucose in HK-2 cells by inhibiting extracellular matrix deposition and epithelial-mesenchymal transition and by reducing oxidative stress. Further investigations are needed to evaluate the clinical application of this compound in diabetic nephropathy. Keywords: Tanshinone IIA, Diabetic nephropathy, HK-2 cells, Fibrosi

    Physics perspectives of heavy-ion collisions at very high energy

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    Heavy-ion collisions at very high colliding energies are expected to produce a quark-gluon plasma (QGP) at the highest temperature obtainable in a laboratory setting. Experimental studies of these reactions can provide an unprecedented range of information on properties of the QGP at high temperatures. We report theoretical investigations of the physics perspectives of heavy-ion collisions at a future high-energy collider. These include initial parton production, collective expansion of the dense medium, jet quenching, heavy-quark transport, dissociation and regeneration of quarkonia, photon and dilepton production. We illustrate the potential of future experimental studies of the initial particle production and formation of QGP at the highest temperature to provide constraints on properties of strongly interaction matter.Comment: 35 pages in Latex, 29 figure

    Preparation of PdCoIr Tetrahedron Nanocatalysts and Its Performance toward Ethanol Oxidation Reaction

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    钯(Pd)基催化剂是直接乙醇燃料电池研究中广泛使用的催化剂,进一步提升其性能是推动燃料电池发展的重要方向。本文用一步水热法制备出四面体结构PdCo(PdCo tetrahedron,记为PdCo-TH)和少量铱(Ir)掺杂的PdCo四面体合金纳米粒子(记为PdCoIr-TH)。经TEM、ICP、XPS及CV等表征证实,PdCoIr-TH为三元合金纳米粒子,且掺杂的Ir元素倾向分布在催化剂表层。相比于商业Pd/C催化剂,PdCo-TH/C和PdCoIr-TH/C对乙醇电氧化的催化性能显著增强。研究结果表明,Pd9Co1Ir0.1-TH/C在低电位(< -0.25 V)下具有最高的乙醇电氧化活性和稳定性。Ir掺杂不仅提高了催化剂抗CO毒化的能力还有利于乙醇起始氧化电位负移。同时,随着Ir含量的增加,所制备的纳米催化剂的乙醇电氧化C1产物选择性也随之升高。针对不同组成催化剂反应性的差异,本文认为Co与Ir位点上容易产生OHad物种,这将有利于活性Pd位点上乙醇电氧化中间反应物种的有效转化。除了以上的各位点间的协同效应,三元合金的形成,进一步调控了Pd的d带电子结构,从而促进了催化剂反应性的改变。As a new energy conversion device, direct ethanol fuel cells (DEFCs) are widely concerned because of their remarkable advantages such as high theoretical energy density and wide fuel sources. However, the rapid development of DEFCs has been severely impeded due to the sluggish kinetic process and toxic intermediates especially in their anodic reactions. Palladium (Pd)-based materials are considered to be excellent anode catalysts for DEFCs, especially under alkaline conditions. And further improving their performance is an important direction to promote the development of DEFCs. Surface structure and composition are the key factors affecting the performance of catalysts which can be improved by reasonable regulation. It is reported that high-index faceted structures and element doping are beneficial to improve the performance of catalyst. In this work, the advantages of these two strategies were used comprehensively to prepare Pd-based catalysts with high efficiency. Palladium cobalt (PdCo) and Ir-doped PdCo tetrahedron alloy nanocatalysts (denoted by PdCo-TH and PdCoIr-TH, respectively) have been successfully prepared by one-step hydrothermal method. The characterization results of TEM, ICP, XPS and CV show that the PdCo-TH binary and PdCoIr-TH ternary alloys were formed, while Ir element was mainly distributed on the PdCoIr-TH surface. Compared with the commercial Pd/C, the PdCo-TH/C and PdCoIr-TH/C exhibited the enhanced catalytic properties toward ethanol oxidation reaction in alkaline solutions. Particularly, the Pd9Co1Ir0.1-TH/C catalyst showed the best activity and stability toward EOR, especially at low potentials (< -0.25 V). And Ir sites not only resisted CO poison effectively, but also shifted the initial oxidation potential of ethanol negatively. Meanwhile, the selectivity of C1 products during the electrocatalytic oxidation of ethanol has been greatly improved with the increase of Ir content. The enhanced reactivities of PdCo-TH/C and PdCoIr-TH/C could be attributed to: (a) The coexistence of Co sites and Ir sites on the surfaces can generate OHad species which can promote the oxidation of intermediate adsorbed species on Pd sites and (b) the negative shift in electron binding energy of Pd due to the addition of Ir may make reaction intermediates desorb more difficultly, which might make the reactivity of PdCoIr-TH/C differ from that of PdCo-TH/C. This research work has demostrated a strategic approach for future development in high efficiency catalysts used for DEFCs.国家自然科学基金项目(21802112);国家自然科学基金项目(21773198)通讯作者:黄蕊,孙世刚E-mail:[email protected];[email protected]:RuiHuang,Shi-GangSunE-mail:[email protected];[email protected]厦门大学化学化工学院,固体表面物理化学国家重点实验室,福建 厦门 361005State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, Chin

    The LAMOST Survey of Background Quasars in the Vicinity of the Andromeda and Triangulum Galaxies -- II. Results from the Commissioning Observations and the Pilot Surveys

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    We present new quasars discovered in the vicinity of the Andromeda and Triangulum galaxies with the LAMOST during the 2010 and 2011 observational seasons. Quasar candidates are selected based on the available SDSS, KPNO 4 m telescope, XSTPS optical, and WISE near infrared photometric data. We present 509 new quasars discovered in a stripe of ~135 sq. deg from M31 to M33 along the Giant Stellar Stream in the 2011 pilot survey datasets, and also 17 new quasars discovered in an area of ~100 sq. deg that covers the central region and the southeastern halo of M31 in the 2010 commissioning datasets. These 526 new quasars have i magnitudes ranging from 15.5 to 20.0, redshifts from 0.1 to 3.2. They represent a significant increase of the number of identified quasars in the vicinity of M31 and M33. There are now 26, 62 and 139 known quasars in this region of the sky with i magnitudes brighter than 17.0, 17.5 and 18.0 respectively, of which 5, 20 and 75 are newly-discovered. These bright quasars provide an invaluable collection with which to probe the kinematics and chemistry of the ISM/IGM in the Local Group of galaxies. A total of 93 quasars are now known with locations within 2.5 deg of M31, of which 73 are newly discovered. Tens of quasars are now known to be located behind the Giant Stellar Stream, and hundreds behind the extended halo and its associated substructures of M31. The much enlarged sample of known quasars in the vicinity of M31 and M33 can potentially be utilized to construct a perfect astrometric reference frame to measure the minute PMs of M31 and M33, along with the PMs of substructures associated with the Local Group of galaxies. Those PMs are some of the most fundamental properties of the Local Group.Comment: 26 pages, 6 figures, AJ accepte

    Upregulation of CCNB2 and Its Perspective Mechanisms in Cerebral Ischemic Stroke and All Subtypes of Lung Cancer: A Comprehensive Study

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    Cyclin B2 (CCNB2) belongs to type B cell cycle family protein, which is located on chromosome 15q22, and it binds to cyclin-dependent kinases (CDKs) to regulate their activities. In this study, 103 high-throughput datasets related to all subtypes of lung cancer (LC) and cerebral ischemic stroke (CIS) with the data of CCNB2 expression were collected. The analysis of standard mean deviation (SMD) and summary receiver operating characteristic (SROC) reflecting expression status demonstrated significant up-regulation of CCNB2 in LC and CIS (Lung adenocarcinoma: SMD = 1.40, 95%CI [0.98–1.83], SROC = 0.92, 95%CI [0.89–0.94]. Lung squamous cell carcinoma: SMD = 2.56, 95%CI [1.64–3.48]. SROC = 0.97, 95%CI [0.95–0.98]. Lung small cell carcinoma: SMD = 3.01, 95%CI [2.01–4.01]. SROC = 0.98, 95%CI [0.97–0.99]. CIS: SMD = 0.29, 95%CI [0.05–0.53], SROC = 0.68, 95%CI [0.63–0.71]). Simultaneously, protein-protein interaction (PPI) analysis indicated that CCNB2 is the hub molecule of crossed high-expressed genes in CIS and LC. Through Multiscale embedded gene co-expression network analysis (MEGENA), a gene module of CIS including 76 genes was obtained and function enrichment analysis of the CCNB2 module genes implied that CCNB2 may participate in the processes in the formation of CIS and tissue damage caused by CIS, such as “cell cycle,” “protein kinase activity,” and “glycosphingolipid biosynthesis.” Afterward, via single-cell RNA-seq analysis, CCNB2 was found up-regulated on GABAergic neurons in brain organoids as well as T cells expressing proliferative molecules in LUAD. Concurrently, the expression of CCNB2 distributed similarly to TOP2A as a module marker of cell proliferation in cell cluster. These findings can help in the field of the pathogenesis of LC-related CIS and neuron repair after CIS damage

    AIDA directly connects sympathetic innervation to adaptive thermogenesis by UCP1

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    AIDA最早是由林圣彩教授团队首先鉴定和命名的。2007年林圣彩教授团队与孟安明院士团队合作发现AIDA在斑马鱼体轴发育中的功能(Rui, 2007)。2018年,林圣彩教授团队首次发现了AIDA在哺乳动物中的功能,即AIDA介导的内质网降解途径通过降解脂肪合成途径中的关键酶,而限制膳食脂肪在肠道的吸收这一内在抵御肥胖(Luo, 2018)。而本次成果揭示了AIDA在棕色脂肪组织中特定的功能。这些工作将AIDA引入了脂质应激代谢的重要环节,包括脂质吸收和依赖于脂质的产热过程。该论文的共同第一作者为生命科学学院博士生史猛和硕士生黄晓羽,林圣彩教授和林舒勇教授则为共同通讯作者。【Abstract】The sympathetic nervous system–catecholamine–uncoupling protein 1 (UCP1) axis plays an essential role in non-shivering adaptive thermogenesis. However, whether there exists a direct effector that physically connects catecholamine signalling to UCP1 in response to acute cold is unknown. Here we report that outer mitochondrial membrane-located AIDA is phosphorylated at S161 by the catecholamine-activated protein kinase A (PKA). Phosphorylated AIDA translocates to the intermembrane space, where it binds to and activates the uncoupling activity of UCP1 by promoting cysteine oxidation of UCP1.Adipocyte-specific depletion of AIDA abrogates UCP1-dependent thermogenesis, resulting in hypothermia during acute cold exposure. Re-expression of S161A-AIDA, unlike wild-type AIDA, fails to restore the acute cold response in Aida-knockout mice.The PKA–AIDA–UCP1 axis is highly conserved in mammals, including hibernators. Denervation of the sympathetic postganglionic fibres abolishes cold-induced AIDA-dependent thermogenesis. These findings uncover a direct mechanistic link between sympathetic input and UCP1-mediated adaptive thermogenesis.We thank Y. Li, E. Gnaiger, T. Kuwaki, J. R. B. Lighton, E. T. Chouchani and D. Jiang for technical instruction; X. Li and X.-D. Jiang (Core Facility of Biomedical, Xiamen University) for raising the p-S161-AIDA antibody; the Xiamen University Laboratory Animal Center for the mouse in vitro fertilization service and all the other members of S.C.L. laboratory for their technical assistance. This work was supported by grants from the National Key Research and Development Project of China (grant no. 2016YFA0502001) and the National Natural Science Foundation of China (grant nos 31822027, 31871168, 31690101, 91854208 and 82088102), the Fundamental Research Funds for the Central Universities (grant nos 20720190084 and 20720200069), Project ‘111’ sponsored by the State Bureau of Foreign Experts and Ministry of Education of China (grant no. BP2018017), the Youth Innovation Fund of Xiamen (grant no. 3502Z20206028), the Natural Science Foundation of Fujian Province of China (grant no. 2017J01364) and XMU Training Program of Innovation and Entrepreneurship for Undergraduates (grant no. 2019×0666). 该工作得到了厦门大学实验动物中心和生物医学学部仪器平台的重要协助和国家重点研究和发展项目,国家自然科学基金,厦门大学校长基金等的支持

    Potential of Core-Collapse Supernova Neutrino Detection at JUNO

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    JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve
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