907 research outputs found

    Methylglyoxal Impairs Insulin Secretion of Pancreatic β

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    Methylglyoxal (MG) is a highly reactive glucose metabolic intermediate and a major precursor of advanced glycation end products. MG level is elevated in hyperglycemic disorders such as diabetes mellitus. Substantial evidence has shown that MG is involved in the pathogenesis of diabetes and diabetic complications. We investigated the impact of MG on insulin secretion by MIN6 and INS-1 cells and the potential mechanisms of this effect. Our study demonstrates that MG impaired insulin secretion by MIN6 or ISN-1 cells in a dose-dependent manner. It increased reactive oxygen species (ROS) production and apoptosis rate in MIN6 or ISN-1 cells and inhibited mitochondrial membrane potential (MMP) and ATP production. Furthermore, the expression of UCP2, JNK, and P38 as well as the phosphorylation JNK and P38 was increased by MG. These effects of MG were attenuated by MG scavenger N-acetyl cysteine. Collectively, these data indicate that MG impairs insulin secretion of pancreatic β-cells through increasing ROS production. High levels of ROS can damage β-cells directly via JNK/P38 upregulation and through activation of UCP2 resulting in reduced MMP and ATP production, leading to β-cell dysfunction and impairment of insulin production

    Quantitative trait locus (QTL) analysis of pod related traits in different environments in soybean

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    Soybean is an important crop, whose most agronomic traits are quantitative inherited. Mapping of these quantitative trait loci in soybean genes is importance for various applications. A F2:15 RIL population containing 149 lines derived from a cross between Charleston as female and Dongnong 594 as male parent were used for mapping of the QTL of pod related traits. Three agronomic traits showing clear phenotypic variations between parents were investigated and relevant QTLs were analyzed with software WindowsQTL Cartographer V2.5. The pod related traits are podwall thickness, weight of podwall, and ratio of podwall to pod (weight to weight). A total of 67 QTLs were mapped for 3 agronomic traits. Some QTLs identified under all environments tend to be valuable for soybean molecular marker assistant breeding selection.Key words: Soybean, pod traits, QTL, different environments

    B \to (\jpsi,\eta_c) K decays in the perturbative QCD approach

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    In this paper, we calculated the B \to (\jpsi, \eta_c) K decays in the perturbative QCD approach with the inclusion of the partial next-to-leading order (NLO) contributions. We found that (a) when the large enhancements from the known NLO contributions are taken into account, the NLO pQCD predictions for the branching ratios are the following: Br(B^0 \to \jpsi K^0) = 5.2^{+3.5}_{-2.8}\times 10^{-4}, Br(B^+ \to \jpsi K^+) = 5.6^{+3.7}_{-2.9}\times 10^{-4}, Br(B0ηcK0)=5.52.0+2.3×104Br(B^0 \to \eta_c K^0) = 5.5^{+2.3}_{-2.0}\times 10^{-4}, Br(B+ηcK+)=5.92.1+2.5×104Br(B^+ \to \eta_c K^+) = 5.9^{+2.5}_{-2.1}\times 10^{-4}, which are roughly 40% smaller than the measured values, but basically agree with the data within 2σ2-\sigma errors; (b) the NLO pQCD predictions for the CP-violating asymmetries of B \to (\jpsi,\eta_c)K decays agree perfectly with the data.Comment: 18 pages, 3 figures, RevTex. some modifications in content,numerical results change

    Na content dependence of superconductivity and the spin correlations in Na_{x}CoO_{2}\cdot 1.3H_{2}O

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    We report systematic measurements using the ^{59}Co nuclear quadrupole resonance(NQR) technique on the cobalt oxide superconductors Na_{x}CoO_{2}\cdot 1.3H_{2}O over a wide Na content range x=0.25\sim 0.34. We find that T_c increases with decreasing x but reaches to a plateau for x \leq0.28. In the sample with x \sim 0.26, the spin-lattice relaxation rate 1/T_1 shows a T^3 variation below T_c and down to T\sim T_c/6, which unambiguously indicates the presence of line nodes in the superconducting (SC) gap function. However, for larger or smaller x, 1/T_1 deviates from the T^3 variation below T\sim 2 K even though the T_c (\sim 4.7 K) is similar, which suggests an unusual evolution of the SC state. In the normal state, the spin correlations at a finite wave vector become stronger upon decreasing x, and the density of states at the Fermi level increases with decreasing x, which can be understood in terms of a single-orbital picture suggested on the basis of LDA calculation.Comment: version published in J. Phys. Condens. Matter (references updated and more added

    Parallel momentum distribution of the 28^{28}Si fragments from 29^{29}P

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    Distribution of the parallel momentum of 28^{28}Si fragments from the breakup of 30.7 MeV/nucleon 29^{29}P has been measured on C targets. The distribution has the FWHM with the value of 110.5 ±\pm 23.5 MeV/c which is consistent quantitatively with Galuber model calculation assuming by a valence proton in 29^{29}P. The density distribution is also predicted by Skyrme-Hartree-Fock calculation. Results show that there might exist the proton-skin structure in 29^{29}P.Comment: 4 pages, 4 figure

    Epidemiology, causes, clinical manifestation and diagnosis, prevention and control of coronavirus disease (COVID-19) during the early outbreak period

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    __Background:__ The coronavirus disease (COVID-19) has been identified as the cause of an outbreak of respiratory illness in Wuhan, Hubei Province, China beginning in December 2019. As of 31 January 2020, this epidemic had spread to 19 countries with 11 791 confirmed cases, including 213 deaths. The World Health Organization has declared it a Public Health Emergency of International Concern. __Methods:__ A scoping review was conducted following the methodological framework suggested by Arksey and O'Malley. In this scoping review, 65 research articles published before 31 January 2020 were analyzed and discussed to better understand the epidemiology, causes, clinical diagnosis, prevention and control of this virus. The research domains, dates of publication, journal language, authors' affiliations, and methodological characteristics were included in the analysis. All the findings and statements in this review regarding the outbreak are based on published information as listed in the references. __Results:__ Most of the publications were written using the English language (89.2%). The largest proportion of published articles were related to causes (38.5%) and a majority (67.7%) were published by Chinese scholars. Research articles initially focused on causes, but over time there was an increase of the articles related to prevention and control. Studies thus far have shown that the virus' origination is in connection to a seafood market in Wuhan, but specific animal associations have not been confirmed. Reported symptoms include fever, cough, fatigue, pneumonia, headache, diarrhea, hemoptysis, and dyspnea. Preventive measures such as masks, hand hygiene practices, avoidance of public contact, case detection, contact tracing, and quarantines have been discussed as

    Visualizing and Quantifying Intracellular Behavior and Abundance of the Core Circadian Clock Protein PERIOD2

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    SummaryTranscriptional-translational feedback loops (TTFLs) are a conserved molecular motif of circadian clocks. The principal clock in mammals is the suprachiasmatic nucleus (SCN) of the hypothalamus. In SCN neurons, auto-regulatory feedback on core clock genes Period (Per) and Cryptochrome (Cry) following nuclear entry of their protein products is the basis of circadian oscillation [1, 2]. In Drosophila clock neurons, the movement of dPer into the nucleus is subject to a circadian gate that generates a delay in the TTFL, and this delay is thought to be critical for oscillation [3, 4]. Analysis of the Drosophila clock has strongly influenced models of the mammalian clock, and such models typically infer complex spatiotemporal, intracellular behaviors of mammalian clock proteins. There are, however, no direct measures of the intracellular behavior of endogenous circadian proteins to support this: dynamic analyses have been limited and often have no circadian dimension [5–7]. We therefore generated a knockin mouse expressing a fluorescent fusion of native PER2 protein (PER2::VENUS) for live imaging. PER2::VENUS recapitulates the circadian functions of wild-type PER2 and, importantly, the behavior of PER2::VENUS runs counter to the Drosophila model: it does not exhibit circadian gating of nuclear entry. Using fluorescent imaging of PER2::VENUS, we acquired the first measures of mobility, molecular concentration, and localization of an endogenous circadian protein in individual mammalian cells, and we showed how the mobility and nuclear translocation of PER2 are regulated by casein kinase. These results provide new qualitative and quantitative insights into the cellular mechanism of the mammalian circadian clock

    The Hidden Nematic Fluctuations in the Triclinic (Ca0.85La0.15)10(Pt3As8)(Fe2As2)5 Superconductor Revealed by Ultrafast Optical Spectroscopy

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    We reported the quasiparticle relaxation dynamics of an optimally doped triclinic iron-based superconductor (Ca0.85_{0.85}La0.15_{0.15})10_{10}(Pt3_3As8_8)(Fe2_2As2_2)5_5 with bulk TcT_c = 30 K using polarized ultrafast optical pump-probe spectroscopy. Our results reveal anisotropic transient reflectivity induced by nematic fluctuations develops below TnemT_{nem} \approx 120 K and persists in the superconducting states. Measurements under high pump fluence reveal three distinct, coherent phonon modes at frequencies of 1.6, 3.5, and 4.7 THz, corresponding to A1g(1)A_{1g}(1), EgE_g, and A1g(2)A_{1g}(2) modes, respectively. The high-frequency A1g(2)A_{1g}(2) mode corresponds to the cc-axis polarized vibrations of FeAs planes with a nominal electron-phonon coupling constant λA1g(2)\lambda _{A_{1g}(2)} \approx 0.139 ±\pm 0.02. Our findings suggest that the superconductivity and nematic state are compatible but competitive at low temperatures, and the A1gA_{1g} phonons play an important role in the formation of Cooper pairs in (Ca0.85_{0.85}La0.15_{0.15})10_{10}(Pt3_3As8_8)(Fe2_2As2_2)5_5.Comment: 6 pages, 3 figures and Supplemental Material
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