102 research outputs found

    The Evaluation of E-commerce Efficiency in China using DEA-Tobit model: evidence from Taobao data

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    Using the analytical framework of DEA-Tobit, this paper investigates the efficiency of e-commerce in China\u27s provinces based on the cross-section data of 31 provinces in China and the data of e-commerce service providers from Taobao’s open platform. The data envelopment analysis (DEA) is used to calculate the technical efficiency and scale efficiency. Furthermore the paper gives an empirical test on the relationship between the scale efficiency and influencing factors by using the censored Tobit model. The results show there are significant regional differences in the efficiency of e-commerce services in provinces of China, and the Real GDP per capita, the seller number on e-commerce platform, the retail sales and wholesale are important reasons for the different efficiency in each province of China. This study provides a domain-specific, integrative approach in evaluating the E-commerce development combining macro data from National Bureau of Statistics of China and micro data from taobao.com

    Sequential emitter identification method based on D-S evidence theory

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    This paper proposes a novel sequential identification method for enhancing the anti-jamming performance and for accurate recognition rate of the emitters’ individual identification in the complicated environment. The proposed method integrates the D-S evidence theory and features extraction that can get the utmost out of features of information systems and decrease the influence of uncertain factors in the signal processing. Firstly, selected features are extracted from intercepted signals. Then, the proposed self-adaptive fusing rule based on the decision vector is utilized to fuse the evidences that are transformed by features and the previous fusing information. Finally, recognition results can be obtained by judgment rules. The simulation analysis demonstrates that self-adaptive fusing rule can achieve a great balance between computational efficiency and accurate identifying rate. While comparing with other identifying methods, the proposed sequential identifying method can provide more accurate and stable recognition results, which makes the utmost care and use of existing information

    The role of reactive elements in improving the cyclic oxidation performance of Î’- NiAl coatings

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    the bond coat in thermal barrier coating (TBC) system. However, the oxide scale grown on NiAl spalls readily during high-temperature cyclic oxidation. Reactive elements (REs) as well as their oxides dispersions were investigated to improve the cyclic oxidation performance. In this work, the effects of several REs on the adherence of Al2O3/NiAl interface were investigated by first principles theory calculations and experiments. We find that the solubility of the REs in NiAl alloy arrive at an order of Hf \u3eZr\u3eDy\u3eY\u3eLa, all the REs exhibit an affinity for sulfur, with an order of La\u3eDy\u3eY\u3eZr\u3eHf, and direct effects of the REs on the Al2O3/NiAl interface exhibit an order of Hf\u3eY\u3eHf\u3eZr\u3eclean interface\u3eLa. Combined with experimental results, we provide some suggestions on how to choose an appropriate RE. Co-doping of appropriate REs exhibits promising potential in improving the oxide scale adherence but also in reducing the growth rate of the oxides formed on the NiAl alloy or coating as compared to the single RE doping

    Inhibition of pyruvate kinase M2 by reactive oxygen species contributes to the development of pulmonary arterial hypertension

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    Aims Pulmonary arterial hypertension [1] is a proliferative disorder associated with enhanced proliferation and suppressed apoptosis of pulmonary artery smooth muscle cells (PASMCs). Reactive oxygen species (ROS) is implicated in the development of PAH and regulates the vascular tone and functions. However, which cellular signaling mechanisms are triggered by ROS in PAH is still unknown. Hence, here we wished to characterize the signaling mechanisms triggered by ROS. Methods and Results By Western blots, we showed that increased intracellular ROS caused inhibition of the glycolytic pyruvate kinase M2 (PKM2) activity through promoting the phosphorylation of PKM2. Monocrotaline (MCT)-induced rats developed severe PAH and right ventricular hypertrophy, with a significant increase in the P-PKM2 and decrease in pyruvate kinase activity which could be attenuated with the treatments of PKM2 activators, FBP and l-serine. The antioxidant NAC, apocynin and MnTBAP had the similar protective effects in the development of PAH. In vitro assays confirmed that inhibition of PKM2 activity could modulate the flux of glycolytic intermediates in support of cell proliferation through the increased pentose phosphate pathway (PPP). Increased ROS and decreased PKM2 activity also promoted the Cav1.2 expression and intracellular calcium. Conclusion Our data provide new evidence that PKM2 makes a critical regulatory contribution to the PAHs for the first time. Decreased pyruvate kinase M2 activity confers additional advantages to rat PASMCs by allowing them to sustain anti-oxidant responses and thereby support cell survival in PAH. It may become a novel treatment strategy in PAH by using of PKM2 activators

    Therapeutic Angiogenesis of Chinese Herbal Medicines in Ischemic Heart Disease:A Review

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    Ischemic heart disease (IHD) is one of the primary causes of death around the world. Therapeutic angiogenesis is a promising innovative approach for treating IHD, improving cardiac function by promoting blood perfusion to the ischemic myocardium. This treatment is especially important for targeting patients that are unable to undergo angioplasty or bypass surgery. Chinese herbal medicines have been used for more than 2,500 years and they play an important role alongside contemporary medicines in China. Growing evidence in animal models show Chinese herbal medicines can provide therapeutic effect on IHD by targeting angiogenesis. Identifying the mechanism in which Chinese herbal medicines can promote angiogenesis in IHD is a major topic in the field of traditional Chinese medicine, and has the potential for advancing therapeutic treatment. This review summarizes the progression of research and highlights potential pro-angiogenic mechanisms of Chinese herbal medicines in IHD. In addition, an outline of the limitations of Chinese herbal medicines and challenges they face will be presented

    Convex optimization method for quantifying image quality induced saliency variation

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    Visual saliency plays a significant role in image quality assessment. Image distortions cause shift of saliency from its original places. Being able to measure such distortion-included saliency variation (DSV) contributes towards the optimal use of saliency in automated image quality assessment. In our previous study a benchmark for the measurement of DSV through subjective testing was built. However, exiting saliency similarity measures are unhelpful for the quantification of DSV due to the fact that DSV highly depends on the dispersion degree of a saliency map. In this paper, we propose a novel similarity metric for the measurement of DSV, namely MDSV, based on convex optimization method. The proposed MDSV metric integrates the local saliency similarity measure and the global saliency similarity measure using the function of saliency dispersion as a modulator. We detail the parameter selection of the proposed metric and the interactions of sub-models for the convex optimization strategy. Statistical analyses show that our proposed MDSV outperforms the existing metrics in quantifying the image quality induced saliency variation

    Pro-angiogenic Role of Danqi Pill Through Activating Fatty Acids Oxidation Pathway Against Coronary Artery Disease

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    Coronary artery disease (CAD) is one of the leading causes of deaths worldwide. Energy metabolism disorders, including a reduction in fatty acids oxidation and upregulation of glycolysis pathway, are involved in the process of CAD. Therapeutic angiogenesis has become a promising treatment for CAD. Traditional Chinese medicines, such as Danqi Pill (DQP), have been proven to be effective in treating CAD in China for many years. However, the pro-angiogenic effects of DQP based on fatty acids oxidation are still unknown and the mechanism is worthy of investigation. In this study, left anterior descending (LAD) coronary artery was ligated to induce the CAD models in vivo, and cardiac functions were examined using echocardiography. Human umbilical vein endothelial cells (HUVEC) were subjected to H2O2-induced oxidative stress in vitro. The effects of DQP on CAD rat models and in vitro HUVEC were detected. Our results showed that DQP had cardio-protective effects in rat model. The intensity of capillaries in the marginal area of infarction of the rat heart was increased remarkably in DQP group, and the expression of PPARα and VEGF-2 were increased. The key enzymes involved in the transportation and intake of fatty acids, including CPT1A and CD36, both increased. In H2O2-induced endothelial cells injury models, DQP also showed protective roles and promoted capillary-like tube formation. DQP up-regulated key enzymes in fatty acids oxidation in H2O2-treated HUVEC. In addition, inhibition of CPT1A compromised the pro-angiogenic effects of DQP. In conclusion, fatty acids oxidation axis PPARα-CD36-CPT1A was involved in the pro-angiogenic roles of DQP against CAD. Cardiac CPT1A may serve as a target in therapeutic angiogenesis in clinics

    Striatopallidal dysfunction underlies repetitive behavior in Shank3-deficient model of autism

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    The postsynaptic scaffolding protein SH3 and multiple ankyrin repeat domains 3 (SHANK3) is critical for the development and function of glutamatergic synapses. Disruption of the SHANK3-encoding gene has been strongly implicated as a monogenic cause of autism, and Shank3 mutant mice show repetitive grooming and social interaction deficits. Although basal ganglia dysfunction has been proposed to underlie repetitive behaviors, few studies have provided direct evidence to support this notion and the exact cellular mechanisms remain largely unknown. Here, we utilized the Shank3B mutant mouse model of autism to investigate how Shank3 mutation may differentially affect striatonigral (direct pathway) and striatopallidal (indirect pathway) medium spiny neurons (MSNs) and its relevance to repetitive grooming behavior in Shank3B mutant mice. We found that Shank3 deletion preferentially affects synapses onto striatopallidal MSNs. Striatopallidal MSNs showed profound defects, including alterations in synaptic transmission, synaptic plasticity, and spine density. Importantly, the repetitive grooming behavior was rescued by selectively enhancing the striatopallidal MSN activity via a Gq-coupled human M3 muscarinic receptor (hM3Dq), a type of designer receptors exclusively activated by designer drugs (DREADD). Our findings directly demonstrate the existence of distinct changes between 2 striatal pathways in a mouse model of autism and indicate that the indirect striatal pathway disruption might play a causative role in repetitive behavior of Shank3B mutant mice.National Institute of Mental Health (U.S.) (Grant 5R01MH097104
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