171 research outputs found

    Enhancing Learners’ Critical Thinking Ability Through Pedagogical Translation in English Language Teaching

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    The paper explores the strategic use of pedagogical translation in English language teaching (ELT) to enhance Chinese learners’ critical thinking ability. Different from the studies on translation theories and the teaching of translation to English majors, the present study assumes that pedagogical translation is a rational activity which can effectively help learners understand the source language and target language precisely. The translation of four different word categories is discussed and analyzed by using examples. It is concluded that learners can improve their critical thinking ability and language competence through designed translation activities

    Study on the technology and properties of 3D bioprinting SF/GT/n-HA composite scaffolds

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    In this paper, three kinds of natural polymer materials, silk fibroin (SF), gelatin (GT), and nano-hydroxyapatite (n-HA), are mixed as 3D printing bioink to mimic protein polysaccharide and collagen fibers in natural articular cartilage. By changing the SF content, SF/GT/n-HA composite scaffolds with different ratios are prepared using 3D bioprinting technology. The microstructure and morphology, biological properties and mechanical properties of composite scaffolds are characterized. The results show that the printing precision of the bioink with 10% SF is best, and the composite scaffold with 10% SF also exhibits better mechanical properties, whose tensile elastic modulus is 10.60 ± 0.32 MPa and the compression elastic modulus is 1.22 ± 0.06 MPa. These studies are helpful to understand the interaction between SF, GT and n-HA, and provide a theoretical basis for the preparation of better silk fibroin-based composite scaffolds

    Beamforming Design for IRS-and-UAV-aided Two-way Amplify-and-Forward Relay Networks

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    As a promising solution to improve communication quality, unmanned aerial vehicle (UAV) has been widely integrated into wireless networks. In this paper, for the sake of enhancing the message exchange rate between User1 (U1) and User2 (U2), an intelligent reflective surface (IRS)-and-UAV- assisted two-way amplify-and-forward (AF) relay wireless system is proposed, where U1 and U2 can communicate each other via a UAV-mounted IRS and an AF relay. Besides, an optimization problem of maximizing minimum rate is casted, where the variables, namely AF relay beamforming matrix and IRS phase shifts of two time slots, need to be optimized. To achieve a maximum rate, a low-complexity alternately iterative (AI) scheme based on zero forcing and successive convex approximation (LC-ZF-SCA) algorithm is put forward, where the expression of AF relay beamforming matrix can be derived in semi-closed form by ZF method, and IRS phase shift vectors of two time slots can be respectively optimized by utilizing SCA algorithm. To obtain a significant rate enhancement, a high-performance AI method based on one step, semidefinite programming and penalty SCA (ONS-SDP-PSCA) is proposed, where the beamforming matrix at AF relay can be firstly solved by singular value decomposition and ONS method, IRS phase shift matrices of two time slots are optimized by SDP and PSCA algorithms. Simulation results present that the rate performance of the proposed LC-ZF-SCA and ONS-SDP-PSCA methods surpass those of random phase and only AF relay. In particular, when total transmit power is equal to 30dBm, the proposed two methods can harvest more than 68.5% rate gain compared to random phase and only AF relay. Meanwhile, the rate performance of ONS-SDP-PSCA method at cost of extremely high complexity is superior to that of LC-ZF-SCA method

    Endothelial Progenitor Cells Enhance the Migration and Osteoclastic Differentiation of Bone Marrow-Derived Macrophages in vitro and in a Mouse Femur Fracture Model through Talin-1

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    Background/Aims: Bone resorption mediated by osteoclasts plays an important role in bone healing. Endothelial progenitor cells (EPCs) promote bone repair by stimulating neovascularization and osteogenesis. However, the role of EPCs in osteoclast formation and function is not well defined. The aim of this study was to elucidate mechanisms of EPCs in osteoclast formation and function. Methods: In this study, we examined the effects of EPCs on the proliferation, migration and osteoclastic differentiation of primary mouse bone marrow-derived macrophages (BMMs) in a co-culture system in vitro. We also evaluated the effects of EPC co-transplantation on the homing and osteoclastic differentiation of transplanted BMMs in a mouse bone fracture model in vivo. The technology of immunofluorescence, immunohistochemical, western blot, Rt-PCR, cell co-culture and Transwell were used in this study. Results: EPCs secreted TGF-β1 in the EPC-BMM co-culture medium and increased Talin-1 expression in the co-cultured BMMs. Treatment with a TGF-β1 neutralizing antibody or Talin-1 silencing in BMMs completely inhibited BMM osteoclastic differentiation in the co-culture system. These results indicated that the osteoclastogenic effects of EPCs were mediated by TGF-β1-mediated Talin-1 expression in BMMs. In the femur fracture model, BMMs co-transplanted with EPCs exhibited enhanced engraftment into the fracture site and osteoclastic differentiation compared with those transplanted alone. Mice treated with EPC-BMM co-transplantation exhibited increased neovascularization at the fracture site and accelerated fracture healing compared with those treated with BMMs alone. Conclusion: Taken together, the results suggest that EPCs can promote bone repair by enhancing recruitment and differentiation of osteoclast precursors

    Reactive oxidative species (ROS)-based nanomedicine for BBB crossing and glioma treatment: current status and future directions

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    Glioma is the most common primary intracranial tumor in adults with poor prognosis. Current clinical treatment for glioma includes surgical resection along with chemoradiotherapy. However, the therapeutic efficacy is still unsatisfactory. The invasive nature of the glioma makes it impossible to completely resect it. The presence of blood-brain barrier (BBB) blocks chemotherapeutic drugs access to brain parenchyma for glioma treatment. Besides, tumor heterogeneity and hypoxic tumor microenvironment remarkably limit the efficacy of radiotherapy. With rapid advances of nanotechnology, the emergence of a new treatment approach, namely, reactive oxygen species (ROS)-based nanotherapy, provides an effective approach for eliminating glioma via generating large amounts of ROS in glioma cells. In addition, the emerging nanotechnology also provides BBB-crossing strategies, which allows effective ROS-based nanotherapy of glioma. In this review, we summarized ROS-based nanomedicine and their application in glioma treatment, including photodynamic therapy (PDT), photothermal therapy (PTT), chemodynamic therapy (CDT), sonodynamic therapy (SDT), radiation therapy, etc. Moreover, the current challenges and future prospects of ROS-based nanomedicine are also elucidated with the intention to accelerate its clinical translation

    The effect of various pressure of pneumatic uterine bracket by using saccule sterine external stent on incidence of supine hypotensive syndrome

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    Objectives: The saccule uterine external stent with a pneumatic uterine bracket reportedly prevents the incidence of supine hypotension syndrome (SHS) during cesarean section under combined spinal — epidural anesthesia (CSEA). However, the preventive effect is affected by the pressure within pneumatic uterine bracket. This study aims to explore the optimal pressure.Material and methods: One hundred forty-eight pregnant women were selected and randomly divided into three groups: Group A (the control group, n = 49), Group B (n = 49), and Group C (n = 50). The pressure within pneumatic uterine bracket was set at 240 mmHg, 260mmHg, and 280mmHg, respectively, during cesarean section under CSEA for participants in groups A, B and C. The intraoperative comfort rate and incidence of SHS were recorded.Results: No significant difference in the anesthetic efficacy was observed among the three groups (p > 0.05). However, there was a significant difference in the occurrence of SHS, with a reduction of 30 mmHg in blood pressure. The incidence of SHS belong the three groups showed significant differences (36.73% in Group A, 18.37% in Group B and 18.00% in Group C, p < 0.05). In addition, significant differences (p < 0.05) in the intraoperative comfort rate were also found among the three groups, with the comfort rate of 69.39% in group A, 91.84% in group B and 90.00% in Group C.Conclusions: The optimal pressure within pneumatic uterine bracket for preventing SHS hypotension is about 260 mmHg. These findings might contribute to the prevention of SHS

    Neutron imaging of lithium concentration in LiNi0.33Mn0.33Co0.33O2 cathode

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    LiNi0.33Mn0.33Co0.33O2 (NMC) is a promising substitute for LiCoO2 because of its good thermal stability and high energy density. In this work, the lithium concentration distributions in an NMC cathode using neutron computed radiography technique at Oak Ridge National Laboratory’s High Flux Isotope Reactor (HFIR) CG-1D Cold Neutron Imaging Facility. Samples with four different state of charge (SOC) were prepared for neutron imaging: 70% SOC, 100% SOC, 105% SOC, and 110% SOC. The neutron tomographic reconstruction of NMC cathode reveals the information of electrochemical transport and spatial Li distribution inside the cathode. The experimental results were explained by a diffusion numerical model which maps the Li concentration evolution during the electrochemical reactions. The study demonstrates that neutron imaging technique can be a very powerful tool to understand the lithium concentrations and evaluate its state of conditions, thus providing information for design of safe lithium ion batteries and estimating their lives
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