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In the hydraulic loading system, the performance of digital relief valve plays an important role in the dynamic response of load. However, the research on large-flow emulsion relief valve is still far from perfect. In this paper, digital relief valve is taken as the research object. Based on pilot-operated relief valve, a digital control scheme using a linear stepping motor is adopted to regulate the working pressure of relief valve. The structure of relief valve is analyzed and optimized from the aspects of dynamic and internal flow field characteristics to obtain a good working performance. To obtain its accurate working characteristic, the structural model and digital control system of relief valve are established by AMESim and Simulink, respectively, for electrohydraulic cosimulation. The results show that digital relief valve has a better characteristic of real-time dynamic pressure regulation. Therefore, the digital control system could improve the dynamic performance of relief valve, and the design of digital relief valve structure is reasonable and feasible. The simulation method employed in this paper provides a better theoretical basis and reference for the comprehensive research of digital large-flow emulsion relief valves based on the hydraulic loading system.

The axial piston pump is an important industrial power element, and its performance directly affects the operation of the system. However, owing to its complex structure and harsh operational environment, the actual operational performance of the axial piston pump is difficult to be assessed accurately, which makes ensuring the normal operation of the hydraulic system difficult. To improve the evaluation method for an axial piston pump, a comprehensive performance evaluation system was proposed based on analytic hierarchy process (AHP), which could assess the performance of an axial piston pump on the basis of theoretical analysis, test, operator interaction, and application. Considering a model of load-sensitive axial piston pump with good operability as an example, the model development and simulation of the pump were carried out based on AMESim and the pump was tested using a developed performance test bed for axial piston pump. The weights of factors in the evaluation system were determined on the basis of the simulation results, analyses, and calculation. The above results were used to comprehensively analyze the tested pump and design a set of comprehensive performance evaluation software. The evaluation result was nearly identical to the actual usage, which verified the feasibility of the designed evaluation system.

To study the efficacy and tolerability of Daming capsule (DMC) in Chinese patients with hyperlipidemia, a randomized, multi-centre, open-label, parallel-group trial was conducted. Sixty enrolled patients with hyperlipidemia allocated to six medical centers were randomly divided into two groups of 30 individuals each. One group received DMC 2 g b.i.d. for 6 weeks, and the other received pravastatin 10 mg o.d. for 6 weeks. For efficacy assessment, serum total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C) were measured before and after drug treatment. Serum TC and LDL-C levels in the DMC-treatment group were significantly decreased compared with those before treatment (p0.05), while TG and HDL-C levels did not change much. Tolerability was assessed by heart rate (HR), blood pressure (BP), body mass index (BMI), alanine aminotransferase (ALT) and creatinine (Cr), which were not changed in either the DMC or pravastatin groups at 3 and 6 weeks (p0.05). Besides, eight patients experienced diarrhea during DMC treatment and two experienced myalgia and epigastric discomfort during pravastatin treatment. Based on the above results, it was concluded that DMC may be a good candidate for the treatment of hyperlipidemia and further clinical trials are warranted.

Bone marrow mesenchymal stem cell (BMSC) transplantation has been shown to effectively improve cardiac function in experimental animals and patients with myocardial infarction and heart hypertrophy. BMSCs exert potent effects on cardiomyocytes through the inhibition of cardiac apoptosis, the attenuation of cardiac inflammation, etc. However, novel biological actions of BMSCs on cardiomyocytes remain to be explored. The present study was designed to investigate whether BMSCs affect electrophysiological features of neonatal rat ventricular myocytes (NRVMs). BMSCs and NRVMs were indirectly co-cultured at a ratio of 1:10 with a semi-permeable membrane. We found that compared with mono-cultured NRVMs, co-cultured NRVMs exhibited an obvious increase of transient outward potassium current (I(to)), accompanied by significant changes in activation, inactivation and recovery of I(to). Meanwhile, K(V)4.2 mRNA which encodes the channel carrying I(to) was more abundant in co-cultured NRVMs than mono-cultured NRVMs. The increases in basic fibroblast growth factor (bFGF) and insulin growth factor-1 (IGF-1) levels were observed in culture medium of BMSCs. bFGF but not IGF-1 upregulated the K(V)4.2 mRNA expression and enhanced I(to) currents. Taken together, we conclude that BMSCs upregulate I(to) of NRVMs, at least partially, by secreting bFGF that in turn upregulates K(V)4.2 expression and alters the kinetics of I(to).

Viscum coloratum flavonoids (VCF) have been demonstrated to produce a variety of biological actions. An accumulating line of evidence supported the view that VCF may exert protective effects on the cardiovascular system. The aim of the study was to assess the antiarrhythmic activity as well as the electrophysiological properties of VCF. The antiarrhythmic effects of VCF were observed in a rat model of arrhythmia induced by aconitine. VCF significantly and dose-dependently increased the dosage of aconitine required to induce the arrhythmia indexes. Electrophysiological experiment revealed that VCF shortened APD through inhibition of ICa-L.