miR-29a/HMGB1信号通路在高糖高脂诱导的心肌细胞纤维化中的作用

目的：探究miR-29a/HMGB1信号通路在高糖高脂（hyperglycemia and hyperlipidemia, HGHL）诱导的H9C2细胞纤维化过程中的作用。方法：使用含葡萄糖（33 mmol/L）和棕榈酸酯（500 μmol/L）的DMEM培养基干预H9C2细胞24 h用于后续实验。共有8个实验分组，分别为NC组、HGHL组、miR-NC组、mimics组、inhibitor组、pc-HMGB1组、si-HMGB1组和miR-29a mimics+pc-HMGB1组。流式细胞术检测各组H9C2细胞的凋亡率。Western blot实验检测各组H9C2细胞内转化生长因子-β1（TGF-β1）、结缔组织生长因子（CTGF）、基质金属蛋白酶9（MMP-9）、过氧化物酶体增殖剂激活受体γ（PPARγ）和高迁移率族蛋白B1（HMGB1）的表达量。RT-qPCR检测各组细胞中miR-29a以及TGF-β1、CTGF、MMP-9、PPARγ、HMGB1 mRNA的表达水平。划痕实验检测各组H9C2细胞的迁移能力。结果：HGHL干预后，H9C2细胞的凋亡率显著增加（P<0.05），细胞迁移能力显著增强（P<0.05），细胞内TGF-β1、CTGF和MMP-9 mRNA表达水平显著增加（P<0.05），PPARγ mRNA的表达水平显著降低（P<0.05），相应蛋白的表达量也随mRNA的变化发生改变（P<0.05），此外H9C2细胞内miR-29a的表达水平也显著降低（P<0.05）。转染miR-29a mimics后，H9C2细胞因HGHL干预引起的凋亡率增加受到显著抑制（P<0.05），细胞的迁移能力也受到显著抑制（P<0.05），细胞内TGF-β1、CTGF和MMP-9蛋白表达量和mRNA表达水平相较于HGHL组显著降低（P<0.05），PPARγ蛋白表达量和mRNA表达水平显著增加（P<0.05）。转染miR-29a inhibitor后促进了HGHL诱导的H9C2细胞纤维化过程。miR-29a负调控HMGB1蛋白及其mRNA在H9C2细胞内的表达，双荧光素酶报告基因实验结果显示HMGB1是miR-29a的下游靶基因。转染si-HMGB1与转染miR-29a mimics对HGHL诱导的H9C2细胞纤维化作用类似。同时转染miR-29a mimics与pc-HMGB1对HGHL诱导的H9C2心肌细胞纤维化无显著影响。 结论：HGHL干预后显著增加H9C2细胞的凋亡率，增强其迁移能力和纤维化的过程。同时HGHL干预显著下调miR-29a在细胞内的表达水平，miR-29a通过负调控HMGB1在细胞内的表达进而影响HGHL诱导的H9C2细胞纤维化。     

Effect of an abrupt change in pulling rate on microstructures of directionally solidified Al2O3-Er3Al5O12 eutectic and off-eutectic composite ceramics

Directionally solidified microstructures of Al₂O₃-Er₃Al₅O₁₂ eutectic and off-eutectic in situ composite ceramics were explored under abrupt-change pulling rate conditions. Corresponding temperature distributions and interface locations were studied. In eutectic composition, fluctuation of eutectic spacing occurred when the pulling rate increased abruptly. A gradually increase or abrupt increase in eutectic spacing was observed when the pulling rate decreased abruptly. In hypoeutectic and hypereutectic compositions, formation of the primary phases were suppressed when the pulling rate increased abruptly from 10?µm/s to 100?µm/s, while primary phases precipitated when the pulling rate decreased abruptly from 100?µm/s to 10?µm/s. The interface altitude decreased after the pulling rate increased abruptly, but increased after the pulling rate decreased abruptly. The liquid composition restriction (around the eutectic composition) at the eutectic interface plays an important role in the suppression of the primary dendrite and coupled eutectic oxides can be obtained in off-eutectic compositions even under higher solidification rate conditions.     

一种汽车顶盖抗雪压动态仿真分析方法

目前顶盖雪压静态仿真分析方法的雪压计算值与测试值存在偏差,并且不能反映顶盖实际变形的位置和整体变形模式。为改进静态仿真分析方法,提出一种非线性显式计算的动态仿真分析方法,并以某乘用车为例,通过试验验证了其可靠性及有效性,为顶盖的研发设计提供了参考。     

铜基化合物的可见光催化研究进展

与传统贵金属光催化剂相比，铜基光催化剂具有价格低廉、绿色环保、反应条件温和、光催化活性可调节等优势，受到合成化学家们广泛关注。本文简述了铜基催化剂的光催化历史，回顾了近五年来铜基化合物在可见光催化领域的研究成果与进展，总结了铜基催化剂的独立光催化机理与协同光催化机理；简要阐述了铜催化剂在不同类型反应中的应用，重点讨论了铜(Ⅰ)催化剂在烯烃官能化、碳-碳偶联、碳-杂偶联、原位催化等反应中的应用研究，表明铜基化合物在光催化合成领域具有很大的应用潜力。对未来的研究工作进行了展望，指出拓展催化剂的反应适用性、探索催化剂的氧化还原能力、进一步开发催化剂在手性合成中的应用将是该领域的研究重点。     

Brief Review of Precipitated Iron-Based Catalysts for Low-Temperature Fischer–Tropsch Synthesis

Topics in Catalysis - Fischer–Tropsch synthesis (FTS) is a promising way to produce clean liquid fuels and high value-added chemicals from low-value carbon-containing resources such as coal,...     

Alloy optimisation of bainitic steel for large plastic mould

Based on the phase transformation theories, especially the T₀ concept of bainite transformation, alloy optimisation of bainitic steel with carbides has been carried out aiming at the produce of plastic mould with large cross-section. The effect of manganese and silicon on proeutectoid ferrite and bainite transformation is explored by dilatometric analysis, XRD and different microscopy techniques. The results show that after the alloy optimisation, the transformation of proeutectoid ferrite is suppressed and when the cooling rate is lower than 0·1°C?s^??1, the new lower bainite transformation appears by decreasing carbon capacity of austenite and promoting carbide precipitation. Industrial production proves that the optimised alloy SDP1 can meet the demand for the plastic mould with the thickness of 1050?mm.     

基于AMESim的液压马达加载系统研究

液压马达作为液压系统的执行元件在工程机械上广泛应用,针对液压马达加载工况下的输出特性,利用Simulink和AMESim软件对系统进行联合仿真建模,并对系统的运行状态、控制性能、回收性能进行研究,对液压马达加载系统的设计和改进具有重要的参考意义。     

Physicochemical characteristics,antioxidant capacity and thermodynamic properties of purple-fleshed potatos dried by radio frequency energy

Abstract

The impacts of using radio frequency (RF) energy to dry purple-fleshed potatoes were investigated and compared to infrared radiation (IR) and microwave (MW) drying techniques. The gelatinization rate, color, flavor, morphological, and structural characteristics, thermodynamic properties, as well as antioxidant capacity were examined. The results indicated that the drying time of RF (70?min) and MW (21?min) were shorter than IR (105?min). The gelatinization ratio of MW, RF, and IR were 94.4?±?2.0, 88.3?±?1.4, and 64.5?±?1.1%, respectively. The degree of crystallization of purple-fleshed potato powder decreased with all three drying methods. RF-dried potatoes were able to retain higher polyphenols (loss rate: 4.3%), total anthocyanin (3.7%), and total flavonoid content (35.1%), whereas IR showed the lowest retention. The content of polyphenols also decreased significantly. Furthermore, after RF heating, the scavenging of free radicals was higher compared to MW and IR.