低牌号球墨铸铁风冷强化工艺的试验研究

研究了风冷热处理对低牌号球墨铸铁(QT450-10)组织和性能的影响.利用对比法和网格法对珠光体组织进行了定量分析,并测试了风冷前后球墨铸铁的力学性能,分析了球墨铸铁风冷强化的微观机制.结果表明,QT450-10球铁经风冷强化以后,其内部组织由原来85%的铁素体基体转变成90%以上的珠光体,且经测量的珠光体片层间距仅为0.45μm,这种细珠光体的片层结构是导致球墨铸铁的抗拉强度由原来的495 MPa增至905 MPa的主要原因.     

混合动力电动汽车冲击度的试验

为提高混合动力电动汽车的驾驶性能,将冲击度作为评价指标研究车辆的驾驶性能.通过试验研究找到提高整车控制品质、改善混合动力电动汽车驾驶性能的方法.以含有机械式自动变速器的某型混合动力轿车为研究对象,通过对车辆在整个行驶过程中产生冲击度的机理进行分析,设计出相应的试验方案,对车辆在起步、驱动状态切换、换挡以及制动等典型过程中的冲击度进行试验研究.试验结果表明,优化离合器分合速度,协调控制发动机和电动机的转速、转矩可以有效减小车辆冲击度.     

Achieving Better Super-cooling in a Two-Stage Transient Thermoelectric Device with Constraint-Free Pulse Current by Multi-Objective Optimization

As a promising energy conversion technology,transient thermoelectric device has potential applications in temperature control and refrigeration.The performance ...     

电动葫芦用钢丝绳断裂事故分析

对电动葫芦用钢丝绳断裂事故进行分析,从钢丝绳夹的装配以及钢丝绳断口的扫描电镜形貌、表面缺陷检查、捻制质量、力学性能、金相组织、化学成分等方面进行全面检查,检查与分析结果表明,造成断裂事故的原因是:钢丝绳夹选择的规格太大,与钢丝绳的规格不匹配,造成钢丝绳结构破坏;捻制缺陷导致钢丝绳使用时绳内钢丝受力不均匀和钢丝之间产生挤压损伤;钢丝绳为混钢号生产,造成同直径钢丝抗拉强度差值大和显微组织差别明显。     

A Simple and Efficient Method for the Substrate Identification of Amino Acid Decarboxylases

Amino acid decarboxylases convert amino acids into different biogenic amines which regulate diverse biological processes. Therefore, identifying the substrates of amino acid decarboxylases is critical for investigating the function of the decarboxylases, especially for the new genes predicted to be amino acid decarboxylases. In the present work, we have established a simple and efficient method to identify the substrates and enzymatic activity of amino acid decarboxylases based on LC-MS methods. We chose GAD65 and AADC as models to validate our method. GAD65 and AADC were expressed in HEK 293T cells and purified through immunoprecipitation. The purified amino acid decarboxylases were subjected to enzymatic reaction with different substrate mixtures in vitro. LC-MS analysis of the reaction mixture identified depleted or accumulated metabolites, which corresponded to candidate enzyme substrates and products, respectively. Our method successfully identified the substrates and products of known amino acid decarboxylases. In summary, our method can efficiently identify the substrates and products of amino acid decarboxylases, which will facilitate future amino acid decarboxylase studies.     

Autophagy: A Double-Edged Sword in Male Reproduction

Autophagy, an evolutionarily conserved cell reprogramming mechanism, exists in all eukaryotic organisms. It is a fundamental and vital degradation/recycling pathway that removes undesirable components, such as cytoplasmic organelles, misfolded proteins, viruses, and intracellular bacteria, to provide energy and essential materials for organisms. The success of male reproduction depends on healthy testes, which are mainly composed of seminiferous tubules and mesenchyme. Seminiferous tubules are composed of Sertoli cells (SCs) and various germ cells, and the main functional part of mesenchyme are Leydig cells (LCs). In recent years, a large amount of evidence has confirmed that autophagy is active in many cellular events associated with the testes. Autophagy is not only important for testicular spermatogenesis, but is also an essential regulatory mechanism for the ectoplasmic specialization (ES) integrity of SCs, as well as for the normal function of the blood–testes barrier (BTB). At the same time, it is active in LCs and is crucial for steroid production and for maintaining testosterone levels. In this review, we expanded upon the narration regarding the composition of the testes; summarized the regulation and molecular mechanism of autophagy in SCs, germ cells, and LCs; and concluded the roles of autophagy in the process of spermatogenesis and testicular endocrinology. Through integrating the latest summaries and advances, we discuss how the role of autophagy is a double-edged sword in the testes and may provide insight for future studies and explorations on autophagy in male reproduction.     

Downregulation of P300/CBP-Associated Factor Protects from Vascular Aging via Nrf2 Signal Pathway Activation

Increasing evidence has shown that vascular aging has a key role in the pathogenesis of vascular diseases. P300/CBP-associated factor (PCAF) is involved in many vascular pathological processes, but the role of PCAF in vascular aging is unknown. This study aims to explore the role and underlying mechanism of PCAF in vascular aging. The results demonstrated that the expression of PCAF was associated with age and aging, and remarkably increased expression of PCAF was present in human atherosclerotic coronary artery. Downregulation of PCAF could reduce angiotensin II (AngII)-induced senescence of rat aortic endothelial cells (ECs) in vitro. In addition, inhibition of PCAF with garcinol alleviated AngII-induced vascular senescence phenotype in mice. Downregulation of PCAF could alleviate AngII-induced oxidative stress injury in ECs and vascular tissue. Moreover, PCAF and nuclear factor erythroid-2-related factor 2 (Nrf2) could interact directly, and downregulation of PCAF alleviated vascular aging by promoting the activation of Nrf2 and enhancing the expression of its downstream anti-aging factors. The silencing of Nrf2 with small interfering RNA attenuated the protective effect of PCAF downregulation from vascular aging. These findings indicate that downregulation of PCAF alleviates oxidative stress by activating the Nrf2 signaling pathway and ultimately inhibits vascular aging. Thus, PCAF may be a promising target for aging-related cardiovascular disease.     

Nontoxic and Naturally Occurring Active Compounds as Potential Inhibitors of Biological Targets in Liriomyza trifolii

In recent years, novel strategies to control insects have been based on protease inhibitors (PIs). In this regard, molecular docking and molecular dynamics simulations have been extensively used to investigate insect gut proteases and the interactions of PIs for the development of resistance against insects. We, herein, report an in silico study of (disodium 5′-inosinate and petunidin 3-glucoside), (calcium 5′-guanylate and chlorogenic acid), chlorogenic acid alone, (kaempferol-3,7-di-O-glucoside with hyperoside and delphinidin 3-glucoside), and (myricetin 3′-glucoside and hyperoside) as potential inhibitors of acetylcholinesterase receptors, actin, α-tubulin, arginine kinase, and histone receptor III subtypes, respectively. The study demonstrated that the inhibitors are capable of forming stable complexes with the corresponding proteins while also showing great potential for inhibitory activity in the proposed protein-inhibitor combinations.