901 research outputs found

    Work done by atmospheric winds on mesoscale ocean eddies

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    Mesoscale eddies are ubiquitous in the ocean and dominate the ocean's kinetic energy. However, physical processes influencing ocean eddy energy remains poorly understood. Mesoscale ocean eddy-wind interaction potentially provides an energy flux into or out of the eddy field, but its effect on ocean eddies has not yet been determined. Here we examine work done by atmospheric winds on more than 1,200,000 mesoscale eddies identified from satellite altimetry data, and show that atmospheric winds significantly damp mesoscale ocean eddies, particularly in the energetic western boundary current regions and the Southern Ocean. Furthermore, the large-scale wind stress curl is found to on average systematically inject kinetic energy into anticyclonic (cyclonic) eddies in the subtropical (subpolar) gyres, while mechanically damps anticyclonic (cyclonic) eddies in the subpolar (subtropical) gyres

    Octreotide decreases portal pressure: Hepatic stellate cells may play a pivotal role

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    The aim of this study is to elucidate the effects of different dosages of octreotide on portal pressure in cirrhotic patients and to investigate the mechanism of activated human hepatic stellate cells (HSCs) on octreotide. Thirty-one (31) hepatitis B-related cirrhotic patients were randomly assigned to receive treatment with a 50 (group A, n = 12) or a 25 ìg/h infusion of octreotide for 72 h (group B, n = 14); the control group C (n = 5) received conventional treatment. Dynamic portal pressure was directly measured via a portal vein catheter. To study the cellular mechanism of octreotide, the expression of SSTRs 1-5 in LX-2, an HSC line, was examined by immunostaining and RT-PCR. Intracellular Ca2+ in LX2 wasmeasured by laser scanning confocal microscopy (LSCM). The protein and mRNA levels in all five subtypes of SSTRs were positively expressed in LX-2. Octreotide led to an immediate two-fold drop in intracellular Ca2+ (P < 0.01). Portal pressure, in both groups A and B, decreased significantly (mean, - 20.6%) after octreotide infusion. Octreotide decreased portal pressure in cirrhotic patients by inhibiting HSC contractility by decreasing intracellular Ca2+ concentration via stimulation of all SSTRs on HSCs

    A novel double-chain silver(I) coordination polymer: catena-poly[[[μ-aqua-aqua­disilver(I)]-bis­(μ3-5-methyl­pyrazine-2-carboxyl­ato)] dihydrate]

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    In the title silver(I) coordination polymer, {[Ag2(C6H5N2O2)2(H2O)2]·2H2O}n, the [Ag2(μ2-H2O)(H2O)] cores are extended by anti­parallel 5-methyl­pyrazine-2-carboxyl­ate (L) ligands, forming a novel double-chain structure. Both Ag+ cations show a distorted square-pyramidal coordination. Ag1 is bonded to two water molecules, one L N atom, one N atom and one carboxylate O atom from a neighbouring L, whereas Ag2 is surrounded by two L N atoms, two L carboxylate O atoms and one bridging water molecule. O—H⋯O hydrogen-bonding inter­actions involving water clusters and carboxyl­ate O atoms link the mol­ecules into a three-dimensional supra­molecular architecture, which is further consolidated by weak C—H⋯O inter­actions and π–π stacking inter­actions [centroid–centroid distance 3.643 (5) Å]

    Satellite-derived surface water pCO(2) and air-sea CO2 fluxes in the northern South China Sea in summer

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    An empirical approach is presented for the estimation of the partial pressure of carbon dioxide (pCO(2)) and air-sea CO2 fluxes in the northern South China Sea in summer using satellite-derived sea surface temperatures (SSTs), chlorophyll-a (Chl a) concentrations, and wind fields. Two algorithms were tested. The first used an SST-dependent equation, and the other involved the introduction of Chl a. Regression equations were developed for summer based on in situ data obtained in July, 2004. Using the monthly average SST and Chl a fields derived from the advanced very high resolution radiometer (AVHRR) and the SeaWiFS (sea-viewing wide field of view sensor), respectively, the monthly pCO(2) fields were computed. The derived pCO(2) was compared with the shipboard pCO(2) observations conducted in July, 2000. This resulted in a root-mean-square error of 4.6 mu atm, suggesting that the satellite-derived pCO(2) was in general agreement with the in situ observations. The air-sea CO2 flux was further computed with the aid of the monthly mean QuikSCAT wind speed. We contend that more shipboard data are necessary for refining the empirical algorithms and reducing the uncertainty in the results. (C) 2009 National Natural Science Foundation of China and Chinese Academy of Sciences. Published by Elsevier Limited and Science in China Press. All rights reserved.National Basic Research Program of China [2009CB421200, 2009CB421201]; National Natural Science Foundation of China [40521003, 90711005]; High-Tech R&D Program of China [2006AA09A302, 2007AA09Z127

    Potential effectiveness of traditional Chinese medicine for cardiac syndrome X (CSX): a systematic review and meta-analysis

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    BACKGROUND: Treatment of cardiac syndrome X with unknown pathological mechanism remains a big challenge for clinicians. Complementary and alternative medicine may bring a new choice for its management. The aim of this study is to evaluate the clinical effects of traditional Chinese medicine on cardiac syndrome X patients. METHODS: We systematically searched databases such as Cochrane CENTRAL, PubMed, EMBASE, CBM, Chinese National Knowledge Infrastructure (CNKI), WanFang and VIP, and handsearched relevant journals to identify randomized controlled trials. Following the steps of systematic review recommended by the Cochrane group, we assessed the quality of included studies, extracted valid data and undertook meta-analysis. RESULTS: Twenty one moderate-to low-quality randomized controlled trials involving 1143 patients were included. The results showed that traditional Chinese medicine could improve angina [OR=1.34, 95% CI: 1.2 to 1.50], electrocardiogram (ECG), endothelin-1 (ET-1) levels, prolong exercise duration in treadmill tests, and reduce angina frequency per week compared with routine treatment. No other side effect was reported except two cases of stomach pain. CONCLUSION: Compared with conventional treatment, traditional Chinese medicine shows the potential of optimizing symptomatic outcomes and improving ECG and exercise duration. The efficacy of TCM may find explanation in its pharmacological activity of adjusting the endothelial function. TCM, as a kind of alternative and complementary medicine, may provide another choice for CSX patients
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