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991.
《Tetrahedron》2019,75(29):3917-3922
Recently [11C]mG4P012 (previously [11C]KALB012 and presently named as [11C]PXT012253 by Prexton Therapeutics) had been used as a biomarker during the preclinical development of a potential therapeutic drug, PXT0002331 (an mGluR4 PAM), for PD and l-dopa-induced dyskinesia. [11C]mG4P012 was shown to be a promising PET radioligand for mGluR4 in the monkey brain and for further development in human subjects. However, the previously reported multi-step synthesis of the thiophenol precursor suffered from low yields and difficult workup procedures. To support the translational research of [11C]mG4P012 and the other potential applications, we have developed a new route for synthesis of the thiophenol precursor and optimized the reaction conditions. The synthesis of N-(4-chloro-3-mercaptophenyl)picolinamide from 1-chloro-4-nitrobenzene has been greatly improved from 8% to 52% total yield with easy handling and in gram scales. 相似文献
992.
The electrochemical corrosion behavior of the non‐precious Ni‐Cr Wirolloy, being used in dentistry, was investigated before and after applying of two types of eco‐friendly coatings, polyvinyl silsesquioxane (PVS) and nano‐hydroxyapatite (nHAP) separately in artificial saliva solution at 37 °C for 14 d of immersion. The study aimed to investigate the effectiveness of the introduced coating films in enhancing the corrosion resistance of the alloy, and in decreasing the leaching of the toxic Ni ions from the alloy into the environment. The electrochemical corrosion investigation methods used are; open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. The evaluated results revealed that the electrochemically coated alloy with PVS. prepared at cathodic potential showed higher corrosion resistance and more stable film compared to that prepared by conventional dip‐coating method. At the same time, the nHAP electrochemically coated film provided the best anti‐corrosion properties over all examined time intervals. The obtained results were confirmed via surface analysis, which assured the formation of the prepared coatings on the alloy surface. Chemical analysis of the corrosion product/solutions showed that the effect of electrochemically deposited nHAP and PVS. polymer films in suppression of Ni ions leaching is similar and slightly higher than that of the chemically coated PVS. one; however, all of them are efficient in decreasing the leaching of the risky Ni ions into the solution. 相似文献
993.
994.
Maintaining skin homeostasis is one of the most important factors for skin health. UVB-induced skin photoaging is a difficult problem that has negative impacts on skin homeostasis. So far, a number of compounds have been discovered that improve human skin barrier function and hydration, and are thought to be effective ways to protect skin homeostasis. Potentilla glabra var. mandshurica (Maxim.) Hand.-Mazz. Ethanol Extract (Pg-EE) is a compound that has noteworthy anti-inflammatory properties. However, its skin-protective effects are poorly understood. Therefore, we evaluated the capacity of Pg-EE to strengthen the skin barrier and improve skin hydration. Pg-EE can enhance the expression of filaggrin (FLG), transglutaminase (TGM)-1, hyaluronic acid synthase (HAS)-1, and HAS-2 in human keratinocytes. Moreover, Pg-EE down-regulated the expression of pro-inflammatory cytokines and up-regulated the production of FLG, HAS-1, and HAS-2 suppressed by UVB through inhibition of p38 mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK) pathways. Given the above, since Pg-EE can improve skin barrier, hydration and reduce the UVB-induced inflammation on skin, it could therefore be a valuable natural ingredient for cosmetics or pharmaceuticals to treat skin disorders. 相似文献
995.
在高职课堂讲授电化学知识时,精心设计教学内容,采用模块教学法,将前沿的电化学应用技术渗透在课堂教学中,针对材料专业学生的电化学教学实施思路,适当简化基础理论,让学生了解电化学在新能源、新材料、环境监测等领域的实用技术。 相似文献
996.
997.
采用液相法制备了一种水性氧化石墨烯/聚苯胺复合材料.通过SEM、XRD等手段对复合材料进行了表征,并对制备的复合涂层进行电化学分析和理化性能测试.结果表明,在有机酸的存在下,苯胺单体以充分剥离的氧化石墨烯为成核生长位点,形成了分散良好的氧化石墨烯/聚苯胺复合材料,并保持了氧化石墨烯的层状结构.在复合涂层中,掺杂在聚苯胺分子骨架上的磺基水杨酸(SSA)或十二烷基苯磺酸(DBSA)与聚苯胺协同形成电化学保护作用,有效地将2A12铝合金的腐蚀电流最低降至2×10-7A/cm2左右.该涂层具有良好的强度、韧性和附着等力学性能,并且具有优良的耐盐雾、光照老化等物理稳定性. 相似文献
998.
999.
轻质多层热防护结构的一体化优化设计研究 总被引:2,自引:0,他引:2
大面积防热结构在航天航空领域应用广泛, 其创新结构设计是关键技术之一. 航天飞行器的工作条件要求热防护材料与结构同时具备轻质、隔热、抗冲击的特点, 因此热防护材料与结构正在朝着一体化的方向发展. 基于这种发展趋势, 提出了一种轻质多层热防护结构设计方案. 以一体化多层防热结构在航天器再入过程中的传热为研究对象, 引入大面积防热结构的一维传热假设, 依照航天器再入大气层的温度条件, 建立了防热结构一维非稳态传热的物理模型和封闭的控制方程, 使用差分方法求解方程, 进行一维非稳态的传热分析, 并采用商业有限元软件ABAQUS的传热分析进行验证. 得到了航天器再入大气过程中多层防热结构的各层温度分布, 提出了在满足一定的热约束要求的条件下, 以轻质多层热防护结构的总重量为目标函数的优化设计方法, 得到了多层结构的最优几何参数, 并将优化后的结构进行了有限元承载分析. 相似文献
1000.