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1.
1 Results Classic oxidants require rigorous control of the experimental conditions added with the problem of lack of selectivity. Catalysis by transition metals with environmentally safe oxidants provides synthetic routes to minimize pollution by giving environmental benign by-products. Fe (Ⅵ) is a powerful and a selective oxidant with Fe(Ⅲ) as a by-product, while hydrogen peroxide is clean with water as the only by-product. Separation of sodium or potassium ferrates requires tedious processes. Associat...  相似文献   
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Sensor networks are deployed in many application areas nowadays ranging from environment monitoring, industrial monitoring, and agriculture monitoring to military battlefield sensing. The accuracy of sensor readings is without a doubt one of the most important measures to evaluate the quality of a sensor and its network. Therefore, this work is motivated to propose approaches that can detect and repair erroneous (i.e., dirty) data caused by inevitable system problems involving various hardware and software components of sensor networks. As information about a single event of interest in a sensor network is usually reflected in multiple measurement points, the inconsistency among multiple sensor measurements serves as an indicator for data quality problem. The focus of this paper is thus to study methods that can effectively detect and identify erroneous data among inconsistent observations based on the inherent structure of various sensor measurement series from a group of sensors. Particularly, we present three models to characterize the inherent data structures among sensor measurement traces and then apply these models individually to guide the error detection of a sensor network. First, we propose a multivariate Gaussian model which explores the correlated data changes of a group of sensors. Second, we present a Principal Component Analysis (PCA) model which captures the sparse geometric relationship among sensors in a network. The PCA model is motivated by the fact that not all sensor networks have clustered sensor deployment and clear data correlation structure. Further, if the sensor data show non-linear characteristic, a traditional PCA model can not capture the data attributes properly. Therefore, we propose a third model which utilizes kernel functions to map the original data into a high dimensional feature space and then apply PCA model on the mapped linearized data. All these three models serve the purpose of capturing the underlying phenomenon of a sensor network from its global view, and then guide the error detection to discover any anomaly observations. We conducted simulations for each of the proposed models, and evaluated the performance by deriving the Receiver Operating Characteristic (ROC) curves.  相似文献   
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In this paper, we investigate the performance of a class of M‐estimators for both symmetric and asymmetric conditional heteroscedastic models in the prediction of value‐at‐risk. The class of estimators includes the least absolute deviation (LAD), Huber's, Cauchy and B‐estimator, as well as the well‐known quasi maximum likelihood estimator (QMLE). We use a wide range of summary statistics to compare both the in‐sample and out‐of‐sample VaR estimates of three well‐known stock indices. Our empirical study suggests that in general Cauchy, Huber and B‐estimator have better performance in predicting one‐step‐ahead VaR than the commonly used QMLE. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   
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RhoA/Rho激酶在大鼠阴茎勃起机制中的调节作用   总被引:11,自引:1,他引:10  
一般认为一氧化氮(nitric oxide,NO)释放增加促进小动脉和海绵体平滑肌舒张是导致男性阴茎勃起的主要机制。研究发现内源性血管收缩因子对维持阴茎萎状态有重要作用。应用大鼠模型活体检测使用Y-27632拮抗Rho-激酶活性后对阴茎勃起生理机制的影响;应用免疫转印技术检测 阴茎海绵体内RhoA和Rho激酶蛋白的表达。结果显示在大鼠海绵体组织内有内源性RhoA和Rho激酶蛋白的表达和存在;Y-27632海绵体内注射阻滞RhoA/Rho激酶活性使ICP和CCP/MAP比值明显升高;局部小剂量应用Y-27632对MAP没有明显影响;Y-27632可增强系列电刺激引起的由NO介导的CCP/MAP比值的增加;NO合成酶和鸟苷酸环化酶抑制剂的作用不能阻滞RhoA/Rho激酶抑制剂对大鼠阴茎海绵体平滑肌的松弛作用和CCP/MAP的增加。说明RhoA/Rho激酶信号系统发挥了维持海绵体萎软状态重要作用,这是与NO介导途径不同的阴茎勃起生理调节机制。RhoA/Rho激酶抑制剂可能是ED治疗的新领域新方法。  相似文献   
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Zusammenfassung Die Scholanderschen Befunde über den Sauerstofftransport durch Hämoglobinlösungen werden auf der Basis der irreversiblen Thermodynamik behandelt.  相似文献   
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Heart disease is a leading cause of death in newborn children and in adults. Efforts to promote cardiac repair through the use of stem cells hold promise but typically involve isolation and introduction of progenitor cells. Here, we show that the G-actin sequestering peptide thymosin beta4 promotes myocardial and endothelial cell migration in the embryonic heart and retains this property in postnatal cardiomyocytes. Survival of embryonic and postnatal cardiomyocytes in culture was also enhanced by thymosin beta4. We found that thymosin beta4 formed a functional complex with PINCH and integrin-linked kinase (ILK), resulting in activation of the survival kinase Akt (also known as protein kinase B). After coronary artery ligation in mice, thymosin beta4 treatment resulted in upregulation of ILK and Akt activity in the heart, enhanced early myocyte survival and improved cardiac function. These findings suggest that thymosin beta4 promotes cardiomyocyte migration, survival and repair and the pathway it regulates may be a new therapeutic target in the setting of acute myocardial damage.  相似文献   
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A cycle of activity of aldehyde-fuchsin and performic acid-Victoria blue positive granules was observed in the ovarian pedicle of Dysdercus koenigii during the first ovipositional cycle. The quantitative variation of these granules in the pedicle can also be correlated directly with the increase or decrease of the neurosecretory material in the A-type cells of the pars intercerebralis medialis region of the protocerebrum of the brian.  相似文献   
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Summary Changes in liver acid hydrolase activities during the infection of albino rats,Mastomys or mice withPlasmodium berghei are described. B-Glucosidase, B-galactosidase and N-acetyl-B-D-glucosaminidase exhibited widely different responses with acid phosphatase and cathepsin-B the least responsive and are likely to be causally related to immunity of animals.  相似文献   
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