1,551 research outputs found

    The application of geochemical methods in earthquake prediction in China

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    Several geochemical anomalies were observed before the Haichen, Longling, Tangshan, and Songpan earthquakes and their strong aftershocks. They included changes in groundwater radon levels; chemical composition of the groundwater (concentration of Ca^(++), Mg^(++), Cl^−, SO_4= and HCO_3− ions); conductivity; and dissolved gases such as H_2, CO_2, etc. In addition, anomalous changes in water color and quality were observed before these large earthquakes. Before some events gases escaped from the surface, and there were reports of "ground odors" being smelled by local residents. The large amount of radon data can be grouped into long‐term and short‐term anomalies. The long‐term anomalies have a radon emission build up time of from a few months to more than a year. The short‐term anomalies have durations from a few hours or less to a few months

    Effect of Baicalin on inflammatory mediator levels and microcirculation disturbance in rats with severe acute pancreatitis

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    Objective: To investigate the effect of Bacailin on inflammatory mediator levels and microcirculation disturbance in severe acute pancreatitis (SAP) rats and explore its therapeutic mechanism on this disease. Methods: SAP model rats were randomly divided into model control group and Baicalin treated group, 45 rats in each group. The same number of normal rats were included in sham-operated group. These groups were further subdivided into 3 h, 6 h and 12 h subgroups, respectively (15 rats in each subgroup). At 3, 6 and 12 hours after operation, rats were killed to conduct the following experiments: (1) to examine the mortality rates of rats, the ascites volume and pancreatic pathological changes in each group; (2) to determine the contents of amylase, PLA~2~, TXB~2~, PGE~2~, PAF and IL-1[beta]; in blood as well as the changes in blood viscosity.Results: (1) Compared to model control group, treatment with Baicalin is able to improve the pathological damage of the pancreas, lower the contents of amylase and multiple inflammatory mediators in blood, decrease the amount of ascitic fluid and reduce the mortality rates of SAP rats; (2) at 3 hours after operation, the low-shear whole blood viscosity in Baicalin treated group was significantly lower than that in model control group;at 12 hours after operation, both the high-shear and low-shear whole blood viscosity in Baicalin treated group were also significantly lower than those in model control group.Conclusion: Baicalin, as a new drug, has good prospects in the treatment of SAP since it can exert therapeutic effects on this disease through inhibiting the production of inflammatory mediators, lowering blood viscosity, improving microcirculation and mitigating the pathological damage of the pancreas

    Sliding Mode Disturbance Observer-Based Fractional Second-Order Nonsingular Terminal Sliding Mode Control for PMSM Position Regulation System

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    This paper investigates the position regulation problem of permanent magnet synchronous motor (PMSM) subject to parameter uncertainties and external disturbances. A novel fractional second-order nonsingular terminal sliding mode control (F2NTSMC) is proposed and the finite time stability of the closed-loop system is ensured. A sliding mode disturbance observer (SMDO) is developed to estimate and make feedforward compensation for the lumped disturbances of the PMSM system. Moreover, the finite-time convergence of estimation errors can be guaranteed. The control scheme combining F2NTSMC and SMDO can not only improve performance of the closed-loop system and attenuate disturbances, but also reduce chattering effectively. Simulation results show that the proposed control method can obtain satisfactory position tracking performance and strong robustness

    Anti-proliferation and induced mitochondria-mediated apoptosis of ganoderic acid Mk from Ganoderma lucidum mycelia in cervical cancer HeLa cells

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    Ganoderic acid Mk (GA-Mk), a triterpenoid acid, was isolated from the mycelia of Ganoderma lucidum, and no biological activity of GA-Mk has ever been reported. In this work, we investigated the effect of GA-Mk on the cell proliferation and apoptosis in HeLa cells. The MTT results demonstrated that GA-Mk displayed interesting cytotoxicity toward various human cancer cell lines. Bromodeoxyuridine (BrdU) incorporation assay showed that GA-Mk had a dose-dependent inhibitory effect on proliferation of HeLa cells. The flow cytometry analysis indicated that the treatment of HeLa cells with GA-Mk increased the rate of early and late apoptotic cells in a dose-dependent manner. Furthermore, GA-Mk inducing apoptosis was in association with the burst of intracellular reactive oxygen species (ROS), the decrease of the mitochondrial membrane potential and the increase of caspase-3 and caspase-9 activities. These results demonstrated that GA-Mk was efficiently anti-proliferative and could induce apoptosis of HeLa cells by mitochondria-mediated pathway, and it may serve as a promising candidate for the treatment of cervical cancer.Colegio de Farmacéuticos de la Provincia de Buenos Aire
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