59 research outputs found

    Photocatalytic Decarboxylative Coupling of Arylacetic Acids with Aromatic Aldehydes

    No full text
    An efficient protocol was proposed for the preparation of secondary alcohols in good to excellent yields via photoredox-catalyzed decarboxylative couplings between readily available arylacetic acids and a variety of less reactive (hetero)aromatic aldehydes. The formation of carbanion is the key intermediate in this reaction. Various substituted arylacetic acids and aldehydes were all compatible with this transformation under mild reaction conditions. Furthermore, the current protocol was successfully applied to the direct alcoholization of several drug acids

    Research on Flow Stability and Vibration of an Industrial Hydraulic Turbine

    No full text
    Industrial hydraulic turbines, a kind of small-scaled turbine in a more compact and flexible application, are frequently used in hydrogen cracking, synthesis ammonia, and circulating water field. Besides the energy recovery efficiency, the working stability at variable speed situations is a critical issue, since its rotation speed changes with the flow parameters of the upstream. In this paper, a conventional turbine was numerically investigated under three different rotation speeds and its best efficiency points (BEPs). The velocity profiles, blade load, pressure fluctuation, and vibration features were discussed to form a comprehensive evaluation of turbine stability. The numerical results were validated through turbine external characteristic and vibration tests. The results indicate that the pressure pulsation and vibrations increase when it deviates from the rated rotation speed, but the relatively low flowrate point behaves better than the large point in the aspect of turbine stability; the main reasons are the angle of incidence and rotor circumferential vortex. The conclusions can provide significant reference for turbine hydraulic optimization and engineering application

    A study on the feasibility of homestay in Singapore.

    No full text
    This research project explores the feasibility of homestay in Singapore

    Optimal sampling-based path planning for mobile cable-driven parallel robots in highly constrained environment

    No full text
    Abstract Mobile cable-driven parallel robots (MCDPRs) is a novel concept of cable-driven parallel robots (CDPRs) developed by mounting several mobile bases to discrete the conventional fixed frame. However, the additional mobile bases introduce more degree-of-freedom (DoF), thereby causing the kinematic redundancy. Moreover, mobile bases are susceptible to disturbances causing inconsistent performance. Hence, path planning of MCDPRs becomes a challenging issue due to various internal and external constraints involved. In this article, an optimization-based path planning method is proposed for MCDPRs in highly constrained environments with considering kinematic stability. The proposed approach quickly generates feasible paths for coupled mobile bases by using the developed multi-agent rapidly exploring random tree (MA-RRT). In this process, the tree can share information through the heuristics method to optimize the path, and the adaptive sampling strategy is thus proposed to increase the tree growth efficiency by self-adjusting sampling space. Moreover, the developed dynamic control checking method (DCC) is integrated with MA-RRT to smooth the path and the kinodynamic constraints of mobile bases can be satisfied. To generate the path of the end-effector, two performance metrics are designed considering the kinematic and stability of the MCDPR. Based on the performance metrics, the grid-based search method is developed to generate the path for the end-effector. Finally, the convincing performance of the proposed method is revealed through the dynamic simulation software (CoppeliaSim) and real-world experiments based on a self-built MCDPR prototype

    IL‐38 attenuates myocardial ischemia–reperfusion injury by inhibiting macrophage inflammation

    No full text
    Abstract Background Reperfusion therapy is the most effective approach to resolve coronary occlusion, but myocardial injury caused by excessive inflammation during myocardial ischemia–reperfusion will also pose a new threat to health. Our prior study revealed the expression pattern of interleukin‐38 (IL‐38) in the peripheral blood serum of patients with ischemic cardiomyopathy and the role of IL‐38 in acute myocardial infarction in mice. However, its role and potential mechanisms in myocardial ischemia/reperfusion injury (MIRI) remain to be determined. Methods and Results The left anterior descending artery of C57BL/6 mice was transiently ligated to induce the MIRI model. We found that MIRI induced the expression of endogenous IL‐38, which was mainly produced by locally infiltrating macrophages. Overexpression of IL‐38 in C57BL/6 mice attenuated inflammatory injury and decreased myocardial apoptosis after myocardial ischemia–reperfusion. Furthermore, IL‐38 inhibited lipopolysaccharide‐induced macrophage inflammation in vitro. Cardiomyocytes cocultured with the supernatant of IL‐38‐ and troponin I‐treated macrophages showed a lower rate of apoptosis than controls. Conclusions IL‐38 attenuates MIRI by inhibiting macrophage inflammation. This inhibitory effect may be partially achieved by inhibiting the activation of NOD‐like receptor pyrin domain‐related protein 3 inflammasome, resulting in decreased expression of inflammatory factors and reduced cardiomyocyte apoptosis
    corecore