Antioxidant activity of cyanidins isolated from Ogapy (Acanthopanax divaricatus var. albeofructus) fruits in U937 macrophages

Reactive oxygen species (ROS) are continuously produced in aerobic organisms. Overproduction of ROS is known to play a crucial role in the pathogenesis of many cardiovascular diseases, including atherosclerosis and hypertension. Superoxide dismutase (SOD) and catalase (CAT) play critical roles on the removal of excess ROS. In the present study, we investigated the antioxidant activity of cyanidins from ogapy (Acanthopanax divaricatus var. albeofructus, ADA) fruits against oxidative stress in hydrogen peroxide (H₂O₂)-pretreated U937 macrophages, and explored the plausibility of the therapeutic effect of cyanidins on atherosclerosis. As a result, H₂O₂ generation and lipid peroxidation induced by H₂O₂-pretreatment was decreased by the treatment of cyanidins in U937 macrophages. In addition, increased activity of SOD and CAT was shown in H₂O₂-pretreated cells when treated with cyanidins. Overall, the results obtained in this study showed that cyanidin 3-galactoside and cyanidin 3-lathyroside from ADA fruits could protect macrophages against the damaging effects of H₂O₂ treatment.     

既有居住建筑围护结构节能改造热工性能优化

既有建筑物窗墙比差异较大,在节能改造过程中窗墙比和窗的热工性能对保温层厚度的影响不可忽视。在《严寒和寒冷地区居住建筑节能设计标准》围护结构节能设计规定的基础上,提出围护结构等效传热系数限值,综合考虑朝向、窗墙比、窗户的类型等因素,建立了外墙保温层厚度计算模型和围护结构热工性能参数优化模型,并以徐州地区某既有住宅为例,验证了模型的可行性。     

火灾后方钢管钢筋混凝土短柱承载力分析

在确定了ISO-834标准火灾作用后钢材和混凝土应力应变关系的基础上,首先利用ABAQUS有限元软件建立火灾作用后方钢管钢筋混凝土短柱温度场及力学分析模型,计算结果得到以往试验结果验证。然后分析了截面边长、配筋率、受火时间、含钢率、材料强度等参数对火灾作用后钢管钢筋混凝土短柱承载力的影响规律,结果表明,受火时间、截面边长是影响其承载力的主要因素。最后提出了火灾作用后方钢管钢筋混凝土短柱承载力的理论公式, 为其灾后修复和加固提供参考。     

Numerical investigation of the mechanical component design of a hexacopter drone for real-time fine dust monitoring

Journal of Mechanical Science and Technology - Multi-rotor unmanned aerial vehicles (UAVs) are being widely used in various military and civilian fields because they can replace manned systems in...     

A study on the fracture characteristics of tapered double cantilever beams made of heterogeneous composites with adhesive interfaces

Journal of Mechanical Science and Technology - In this study, CFRP and aluminum properties were investigated by carrying the static experiment on the shape-dependent bonding structure, and designed...     

井下通风网络分析与方案优化

为解决传统矿井通风系统无法满足矿井扩产需求,在以老矿井为例分析其通风现状的基础上,对当前井下通风系统进行测定和评价,并针对其所存在的问题初步提出整改建议;最后,在上述分析的基础上对工作面的需风量进行重新核算,并提出三套优化方案,最终确定方案二为最佳方案.     

Thermal stability,flame retardance,and mechanical properties of polyamide 66 modified by a nitrogen–phosphorous reacting flame retardant

Flame‐retardant polyamide 66 (PA66) was prepared by the polymerization between PA66 prepolymer and N‐benzoic acid (ethyl‐N‐benzoic acid formamide) phosphamide (NENP). Compared with the pure PA66, the flame‐retardant PA66 exhibited better thermal stability, as indicated by thermogravimetric analysis results. The limiting oxygen index was 28% and the UL‐94 test results of the flame‐retardant PA66 indicated a V‐0 rating when the content of the NENP prepolymer was 5 wt %. The flammability and flame‐retardant mechanism of PA66 were also studied with cone calorimetry and scanning electron microscopy/energy‐dispersive X‐ray spectroscopy, respectively. The mechanical properties results show that the flame‐retardant PA66 resin had favorable mechanical properties. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43538.     

Non-vacuum sintering process of WC/W2C reinforced Ni-based coating on steel

Ni-based composite coatings containing varied contents of tungsten carbides on low carbon steel were fabricated. Effects of sintering temperature and tungsten carbides contents on the surface, interface, microstructure and wear resistance of the coatings were investigated using scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, Vickers microhardness tester, bulk hardness tester and pin-on-disc tribometer. The results indicated that with appropriate sintering temperature (1230 °C), smooth coating surfaces can be achieved. Favorable interfaces about 200 μm can be got that both the chemical composition and property of the interfacial region showed gradual transitions from the substrates to the coatings. Microstructure of the coatings consists of tungsten carbides and M7C3/M23C6 in the matrix. With excessive sintering temperature, tungsten carbides tend to dissolve. Ni-based coatings containing tungsten carbides showed much higher level of bulk hardness and wear resistance than ISO Fe360A and ASTM 1566 steels. With increasing contents of tungsten carbides from 25% to 40%, bulk hardness of Ni-based coatings gradually increased. Ni-based coating with 35% tungsten carbides performed the best wear resistance.