Serotonin 5-HT1A receptor-mediated Erk activation requires calcium/calmodulin-dependent receptor endocytosis

Many receptors that couple to heterotrimeric guanine nucleotide-binding (G) proteins mediate rapid activation of the mitogen-activated protein kinases, Erk1 and Erk2. The Gi-coupled serotonin (5-hydroxytryptamine (5-HT)) 5-HT1A receptor, heterologously expressed in Chinese hamster ovary or human embryonic kidney 293 cells, mediated rapid activation of Erk1/2 via a mechanism dependent upon both Ras activation and clathrin-mediated endocytosis. This activation was attenuated by chelation of intracellular Ca2+ and Ca2+/calmodulin (CAM) inhibitors or the CAM sequestrant protein calspermin. The CAM-dependent step in the Erk1/2 activation cascade is downstream of Ras activation, because inhibitors of CAM antagonize Erk1/2 activation induced by constitutively activated mutants of Ras and c-Src but not by constitutively activated mutants of Raf and MEK (mitogen and extracellular signal-regulated kinase). Inhibitors of the classical CAM effectors myosin light chain kinase, CAM-dependent protein kinases II and IV, PP2B, and CAM-sensitive phosphodiesterase had no effect upon 5-HT1A receptor-mediated Erk1/2 activation. Because clathrin-mediated endocytosis was required for 5-HT1A receptor-mediated Erk1/2 activation, we postulated a role for CAM in receptor endocytosis. Inhibition of receptor endocytosis by use of sequestration-defective mutants of beta-arrestin1 and dynamin attenuated 5-HT1A receptor-stimulated Erk1/2 activation. Inhibition of CAM prevented agonist-dependent endocytosis of epitope-tagged 5-HT1A receptors. We conclude that CAM-dependent activation of Erk1/2 through the 5-HT1A receptor reflects its role in endocytosis of the receptor, which is a required step in the activation of MEK and subsequently Erk1/2.     

基于形态学和像素灰度归类的背景重建算法

针对传统背景提取方法在前景运动对象密度较高,亦或前景出现过于频繁时,提取到的背景图像会掺杂很多前景成分的问题,提出了一种基于形态学和像素灰度归类的背景重建算法。该算法通过三帧差分法和形态学把每帧图像分为前景对象和背景区域;然后再用像素灰度归类法只对背景区域进行背景重建,以期在前景对象密度较高时正确重建背景。实验结果证明,新方法能够在车辆密度较高的情况下正确生成背景。     

聚酰亚胺的合成方法及应用

综述了聚酰亚胺的主要合成方法:溶液缩聚法、熔融缩聚法、界面缩聚法和气相沉积法。探讨了聚酰亚胺在聚酰亚胺薄膜、聚酰亚胺纤维、聚酰亚胺胶黏剂和聚酰亚胺泡沫材料方面的应用研究。     

规模化养猪场废水处理技术

阐述了规模化养猪场废水的特点及危害,针对其有机物浓度高、悬浮物多、氨含量高、对环境危害较大、处理困难等问题,提出了实用的综合治理养猪场废水技术。     

推进江西省水权水市场创新实践的思考

推进水权水市场改革是解决水资源供需矛盾、实现水资源节约集约利用的重要措施,也是贯彻落实节水优先方针、推动水利高质量发展的重要举措。本文通过分析江西省水权水市场改革历程和实践现状,理清当前存在的问题,从明晰用水户水权、完善水权水市场制度体系、加强水权交易市场主体培育、探索多种模式的水权交易等方面,提出了新阶段江西省水权水市场改革的对策建议,为今后江西省持续推进水权交易、健康发展水市场提供重要参考。     

超声波法提取番茄红素的研究

研究了采用超声波法从番茄中提取番茄红素,探讨了温度、时间、超声波功率、固液比和提取级数等因素对番茄红素提取率的影响。通过正交试验,确定了最佳工艺条件。实验结果表明,超声波法提取番茄红素的最佳工艺条件为：A3B2C3D2,即温度为55℃,时间为40 min,超声波功率为800 W,固液比为1︰30,其提取量可达到72.4 mg（/100 g）番茄。为进一步开发高效提取与纯化番茄红素提供了基础数据。     

正交优化制备酯化淀粉

以马铃薯淀粉为原料,醋酸乙烯酯为酯化剂,制备低取代度醋酸酯淀粉。研究了各反应因素对产品取代度的影响,用正交试验,确定了其最佳工艺条件,即反应体系pH值10.5~11.5,反应温度26℃,反应时间1 h,酯化剂用量1.5 g。     

粉末冶金压制成形受力情况的研究

本文将多台阶的零件拆分为多个简单圆柱体,并结合圆柱体压坯的有关实验,对原零件做了压制前的受力分析,预先了解到了多台阶零件压制时的受力情况,为粉末冶金产品的压制提供了理论参考。     

以节能供暖为中心全面提高供暖水平

针对我国供暖面临的形势和存在的问题,文中提出,以节能供暖为中心,全面系统总结国内节能供暖的经验和教训,应用系统工程理论提高供暖系统整体节能效果,重视用户合理用热的看法和建议.