527 research outputs found

    A Corpus-Based Critical Analysis of Lexical Choices in Sichuan Earthquake by Chinese and American News Media

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    By combining the Critical Discourse Analysis (CDA) approach with the corpus linguistic method, this study compared the lexical choices employed by two English newspapers, i.e. China Daily and the New York Times, in their coverage of Sichuan earthquake. This study aims to probe into the different political stances and ideology concealed under the news reports. The comparative analysis of the two corpora was conducted at three levels: word frequencies, part-of-speech (POS) frequencies and semantic category frequencies. The results show that there are significant differences among the three levels in the lexical choices about Sichuan earthquake between the two media, which reflect different ideologies and political stances of China and America. By highlighting the endeavor of Chinese relief work, the CDC presents a responsible government and a united Chinese nation. On the contrary, the NYTC focuses more on emphasizing the dictatorship and incompetence of the Chinese government and the scientific and technological backwardness in China, hence creates a negative image of China. On the basis of the present findings, this study intends to be helpful to the teaching of English reading in China

    A New Trend of Knowledge Management: A Study of Mobile Knowledge Management

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    Recent years, knowledge management has developed rapidly in the field of management science and practice. With the evolution of mobile internet technology, it seems to be more prevalent and more important about the research of mobile knowledge management (mKM). Firstly, based on the literature of mKM, different perspectives of mKM research are concluded and analyzed in this paper. Secondly, we make comments on the different literature of mKM. Then, this paper elaborates the strategies and measures to realize mKM under the environment of mobile internet. Finally, this paper provides prospects for the directions in future research

    Simple reverse genetics approach to elucidating the biosynthetic pathway of complex thiopeptide nocathiacin

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    Biothythetic pathway of the most drugable thiopeptide nocathiacin has been elucidated by applying reverse genetics method based on its structural features. The present study provides an efficient approach for an easy access to the biosynthetic gene clusters of complex bioactive peptides that are ribosomally synthesized with extensive posttranslational modifications

    Genetic incorporation of D-Lysine into diketoreductase in Escherichia coli cells

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    D-Lysine has been genetically introduced into diketoreductase in E. coli cells by utilization of an orthogonal Ph tRNA /Lysyl-tRNA synthetase pair. This is the first report on the genetic incoporation of D-amino acids into proteins, which may be generally applicable to a wide variety of applications

    Exosomes From miRNA-126-Modified Endothelial Progenitor Cells Alleviate Brain Injury and Promote Functional Recovery After Stroke

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    Aims: We previously showed that the protective effects of endothelial progenitor cells (EPCs)-released exosomes (EPC-EXs) on endothelium in diabetes. However, whether EPC-EXs are protective in diabetic ischemic stroke is unknown. Here, we investigated the effects of EPC-EXs on diabetic stroke mice and tested whether miR-126 enriched EPC-EXs (EPC-EXs miR126 ) have enhanced efficacy. Methods: The db/db mice subjected to ischemic stroke were intravenously administrated with EPC-EXs 2 hours after ischemic stroke. The infarct volume, cerebral microvascular density (MVD), cerebral blood flow (CBF), neurological function, angiogenesis and neurogenesis, and levels of cleaved caspase-3, miR-126, and VEGFR2 were measured on day 2 and 14. Results: We found that (a) injected EPC-EXs merged with brain endothelial cells, neurons, astrocytes, and microglia in the peri-infarct area; (b) EPC-EXs miR126 were more effective than EPC-EXs in decreasing infarct size and increasing CBF and MVD, and in promoting angiogenesis and neurogenesis as well as neurological functional recovery; (c) These effects were accompanied with downregulated cleaved caspase-3 on day 2 and vascular endothelial growth factor receptor 2 (VEGFR2) upregulation till day 14. Conclusion: Our results indicate that enrichment of miR126 enhanced the therapeutic efficacy of EPC-EXs on diabetic ischemic stroke by attenuating acute injury and promoting neurological function recovery

    EPC-EXs Improve Astrocyte Survival and Oxidative Stress Through Different Uptaking Pathways in Diabetic Hypoxia Condition

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    Background: Hyperglycemia contributes to cardiovascular complications in patients with type 2 diabetes. We confirmed that high glucose (HG) induces endothelial dysfunction and cerebral ischemic injury is enlarged in diabetic mice. Stem cell-released exosomes have been shown to protect the brain from ischemic stroke. We have previously shown that endothelial progenitor cells (EPCs)-released exosomes (EPC-EXs) can protect endothelial cells from hypoxia/reoxygenation (H/R) and HG-induced injury. Here, we aim to investigate the effects of EPC-EXs on astrocytes under H/R and HG-induced injury and whether miR-126 enriched EPC-EXs (miR126-EPC-EXs) have enhanced efficacy. Methods: EPC-EX uptake and co-localization were measured by fluorescent microscopy using PKH26 and DAPI staining. miR-126 enrichment was achieved by transfecting with miR-126 mimics and quantified with real-time PCR. After co-incubation, cell death or injury was measured by using LDH (Lactate Dehydrogenase) assay. Oxidative stress/ROS (reactive oxygen species) generation was measured by DHE (Dihydroethidium) staining and lipid peroxidation assay. Results: The EPC-EXs were effectively taken up by the astrocytes in a concentration as well as time-dependent manners and were co-localized within the nucleus as well as the cytoplasm. Pathway uptake inhibitors revealed that the EPC-EXs are effectively taken up by the clathrin-mediated, caveolin-dependent, and micropinocytosis via PI3K/Akt pathway. H/R and HG-induced a cell injury which could be protected by EPC-EXs evidenced by decreased cell cytotoxicity, oxidative stress, and lipid peroxidation. Moreover, miR-126 overexpression could increase the level of miR-126 in astrocytes and enhance the protective effects of EPC-EXs. Conclusions: These results collectively indicate that the EPC-EXs could protect astrocytes against the HG plus H/R-induced damage

    EPC-EXs Improve Neuronal Survival and Oxidative Stress Through Different Uptaking Pathways in Diabetic Hypoxia Condition

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    Background: Hyperglycemia contributes to cardiovascular complications in patients with type 2 diabetes. We confirmed that high glucose (HG) induces endothelial dysfunction and cerebral ischemic injury is enlarged in diabetic mice. Stem cell-released exosomes have been shown to protect the brain from ischemic stroke. We have previously shown that endothelial progenitor cells (EPCs)-released exosomes (EPC-EXs) can protect endothial cells from hypoxia/reoxygenation (H/R) and HG-induced injury. Here, we aim to investigate the effects of EPC-EXs on astrocytes under H/R and HG-induced injury and whether miR-126 enriched EPC-EXs (EPC-EXsmiR126) have enhanced efficacy. Methods: EPC-EX uptake and co-localization were measured by fluorescent microscopy using PKH26 and DAPI staining. miR-126 enrichment was achieved by transfecting with miR-126 mimics and quantified with real-time PCR. After co-incubation, cell death or apoptosis was measured by using flow cytometric analysis and LDH (Lactate Dehydrogenase) assay. Oxidative stress/ROS (reactive oxygen species) generation was measured by DHE (Dihydroethidium) staining and lipid peroxidation assay. Results: The EPC-EXs were effectively taken up by the astrocytes in a concentration as well as time- dependent manners and were co-localized within the nucleus as well as the cytoplasm. Pathway uptake inhibitors revealed that the EPC-EXs are effectively taken up by the clathrin-mediated, caveolin-dependent, and micropinocytosis via PI3K/Akt pathway. H/R and HG-induced a cell injury which could be protected by EPC-EXs evidenced by decreased cell apoptosis, cell cytotoxicity, oxidative stress, and lipid peroxidation. Moreover, miR-126 overexpression could enhance the protective effects of EPC-EXs. Conclusions: These results collectively indicate that the EPC-EXs could protect astrocytes against the HG plus H/R-induced damage

    An exhaustive research and analysis on seismic performance of prefabricated concrete shear wall structure

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    In order to accelerate the process of building industrialization, improve the overall stability and construction quality of the building. In this paper, a bolted connection method is designed to study the seismic performance of the composite concrete shear wall specimens with horizontal split joints from the aspects of bearing capacity, ductility, energy dissipation, deformation capacity and failure mode. The test results show that the bolted concrete shear wall is feasible and the connectors can effectively connect the upper and lower precast shear walls to form a whole with certain lateral stiffness. The energy dissipation capacity of the specimens is similar to that of other prefabricated concrete shear wall structures with “self-reduction”. The displacement Angle is greater than 1/120 of the limit value of the displacement Angle between elastic-plastic layers under the action of large earthquakes, and the specimen has good deformation capacity. The energy dissipation capacity of the structure from dynamics perspective reveals that smaller capacity of the specimen by providing energy dissipation factor E= 0.24 and equivalent viscous damping coefficient of 0.038

    Resource-Adaptive Newton's Method for Distributed Learning

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    Distributed stochastic optimization methods based on Newton's method offer significant advantages over first-order methods by leveraging curvature information for improved performance. However, the practical applicability of Newton's method is hindered in large-scale and heterogeneous learning environments due to challenges such as high computation and communication costs associated with the Hessian matrix, sub-model diversity, staleness in training, and data heterogeneity. To address these challenges, this paper introduces a novel and efficient algorithm called RANL, which overcomes the limitations of Newton's method by employing a simple Hessian initialization and adaptive assignments of training regions. The algorithm demonstrates impressive convergence properties, which are rigorously analyzed under standard assumptions in stochastic optimization. The theoretical analysis establishes that RANL achieves a linear convergence rate while effectively adapting to available resources and maintaining high efficiency. Unlike traditional first-order methods, RANL exhibits remarkable independence from the condition number of the problem and eliminates the need for complex parameter tuning. These advantages make RANL a promising approach for distributed stochastic optimization in practical scenarios
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