5,210 research outputs found

    Cardiotonic Modulation in Heart Failure Insights From Traditional Chinese Medicine∗

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    Medicinal herbs have been used over the past centuries for restoring the body's homeostatic balance. Contemporary use of herbal supplements remains widespread in many cultures as treatment for specific ailments. Many possess cardiovascular actions, and some interact with cardiac medications. However, there is variable scientific evidence with respect to their safety and efficacy, and few have been subjected to the same rigorous evaluation processes and regulations as contemporary pharmaceuticals (1). In the field of heart failure, we have also witnessed the failure of promising naturopathic therapies like hawthorn extract in translating their potential benefits in rigorous clinical trials (2,3)

    Dealing with Uncertainty in Engineering Design for Large-Scale Gravel Soil Slopes in the Three Gorges Reservoir Zone

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    The objective of this paper is to first present a general formulation for analysis of uncertainties and evaluation of risks associated with large-scale slopes. The risks may be expressed in terms of the reliability of the system and the consequence. Preliminary studies regarding the mitigation of landslides in the Three-Gorge reservoir zone (TGRZ) of the Yangtze River is presented next. At the normal water level of 175 m, the Three-Gorge reservoir stretches for 665 km along the Yangtze River and extends into many tributaries. Some 684 colluvial deposits, ancient slides and hanging rock blocks, which are larger than 100,000 m3 individually, and numerous smaller landslides have been identified. Since 2001, over 650 landslides of varies sizes and 2300 cut slopes at low elevations in the Chongqing section of the Yangtze River have been or are being stabilized. This paper deals with three subjects related to the landslides in the TGRZ. The general characteristics of the landslides and the consequences of these landslides are described first. The main causes of activation are considered to be rainfall infiltration, reservoir level fluctuations, and human activities. An attempt is then made to summarize the uncertainties in the design of the slope stabilization works against slope failure due to rainfall infiltration and reservoir level changes. The uncertainties discussed include those involved in the selection of design soil parameters and design-loading combinations, determination of pore-water pressures and potential slip surfaces, and use of analysis models. Finally a design scenario tree is developed to evaluate the landslide risk and to assist risk-investment decisions

    Advanced methodology for storm sewer design—phase II

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    This report describes further development of computer models for determining the diameter, slope and elevations of each pipe in a storm drainage system in which the layout and manhole locations are specified. The design procedure is based on a least-cost criterion and utilizes discrete differential dynamic programming as the search technique. In this phase of the study a detention storage capability has been added to the model using two approaches. The first approach requires the specification of a maximum allowable outflow and computes the required storage. The second approach determines the storage volume such that the sum of the storage and pipe system costs is a minimum. The procedure for computation of expected damage costs has been changed to reflect the variation of flood damage with flood volume. Also a surface runoff component has been added. This option uses the hydrograph generation portion of the Illinois Urbana Drainage Area Simulator model. Improved cost specification methods as well as flexible pipe elevation constraint capabilities have been added. The new developments are illustrated using two example basins.U.S. Department of the InteriorU.S. Geological SurveyOpe

    Fabrication and superconductivity of NaxTaS2 crystals

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    In this paper we report the growth and superconductivity of NaxTaS2Na_xTaS_2 crystals. The structural data deduced from X-ray diffraction pattern shows that the sample has the same structure as 2H−TaS22H-TaS_2. A series of crystals with different superconducting transition temperatures (TcT_c) ranging from 2.5 K to 4.4 K were obtained. It is found that the TcT_c rises with the increase of NaNa content determined by Energy-Dispersive x-ray microanalysis(EDX) of Scanning Electron Microscope (SEM) on these crystals. Compared with the resistivity curve of un-intercalated sample 2H−TaS22H-TaS_2 (TcT_c = 0.8 K, TCDW≈T_{CDW} \approx 70 K), no signal of charge density wave (CDW) was observed in samples Na0.1TaS2Na_{0.1}TaS_2 and Na0.05TaS2Na_{0.05}TaS_2. However, in some samples with lower TcT_c, the CDW appears again at about 65 K. Comparison between the anisotropic resistivity indicates that the anisotropy becomes smaller in samples with more NaNa intercalation (albeit a weak semiconducting behavior along c-axis) and thus higher TcT_c. It is thus concluded that there is a competition between the superconductivity and the CDW. With the increase of sodium content, the rise of TcT_c in NaxTaS2Na_xTaS_2 is caused mainly by the suppression to the CDW in 2H−TaS22H-TaS_2, and the conventional rigid band model for layered dichalcogenide may be inadequate to explain the changes induced by the slight intercalation of sodium in 2H−TaS22H-TaS_2.Comment: 8 pages, 13 figures, To appear in Physical Review

    Advanced methodologies for design of storm sewer systems

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    This report describes the development of a series of computer models capable of determining the diameter, slope and crown elevations of each sewer in a storm drainage system in which the layout and manhole locations are predetermined. The criterion for design decisions is the generation of a least-cost system. The basis for all of the models is the application of discrete differential dynamic programing (DDDP) as the optimization tool. Two important concepts are introduced as optimal model components: hydrograph routing and risks and uncertainties in designs. Three routing procedures are adopted, each with its own advantages. Expected flood damage costs are evaluated through the analysis of numerous risks and uncertainties associated with the design. This analysis permits the estimation of the probability of exceeding the capacity and the corresponding expected assessed damage of any sewer in the system. The expected damage cost is added to the installation cost to obtain the total cost which is then minimized in the DDDP procedure. Two example sewer systems are used as a basis for illustrating different aspects of the various least-cost design models and developing user guidelines.U.S. Department of the InteriorU.S. Geological SurveyOpe

    Cellular uptake and imaging studies of gadolinium-loaded single-walled carbon nanotubes

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    postprintThe 18th Joint Annual Meeting of ISMRM-ESMRMB, Stockholm, Sweden, 1-7 May 2010
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