A primary goal of broadcasting in vehicular ad hoc network (VANET) is to improve the road safety by transmitting alert messages to all surrounding vehicles as soon as possible. In this paper, we adopt the concept of o...A primary goal of broadcasting in vehicular ad hoc network (VANET) is to improve the road safety by transmitting alert messages to all surrounding vehicles as soon as possible. In this paper, we adopt the concept of opportunistic routing and propose a multiple candidate relays opportunistic broadcast (MCROB) protocol for VANET. The MCROB protocol is a sender-driven broadcast scheme independent of node density. The packet delivery ratio (PDR) is derived and an expected transmission speed (ETS) for the MCROB is proposed. A priority rule for selecting a proper candidate relay and an adaptive algorithm for forwarding timers of candidate relays are also presented in this paper. Simulations show that MCROB is adaptive to the rapid changing of network conditions. It keeps a low communication overhead introduced by the broadcast and increases the average transmission speed by around 40%.展开更多
文摘目的通过网络药理学及分子对接技术预测金振口服液(Jinzhen Oral Liquid,JOL)干预新型冠状病毒肺炎(COVID-19)的作用机制。方法通过文献挖掘以及DisGeNET、OMIM、KEGG、UniProt数据库联用检索与COVID-19相关的蛋白靶点。借助Traditional Chinese Medicine Network(TCMN)信息平台检索JOL中的化合物,运用Cytoscape3.2.1构建药材-化合物-靶点网络来预测JOL治疗COVID-19的活性成分及作用靶点。在RCSBPDB数据库中检索获取新型冠状病毒(SARS-CoV-2)3CL水解酶(3CLpro)和血管紧张素转化酶Ⅱ(ACE2)的晶体结构,借助AutoDock Vina软件将活性化合物与2个蛋白进行分子对接。结果药材-化合物-靶点网络包含异甘草酸内酯、贝母辛、番泻苷B等75个化合物分别来自甘草、大黄和平贝母3味药材,哺乳动物雷帕霉素靶蛋白(m TOR)、Janus激酶3(JAK3)、丝裂原活化蛋白激酶激酶1(MEK1)等28个靶点。网络特征分析阐明了JOL治疗COVID-19的9个关键化合物(异甘草酸内酯、甘草内酯、去氢鄂贝定碱、desoxo-glabrolid-acetate、贝母辛、贝母素乙、乌苏里啶酮、西贝素和euchrenone A5)以及10个潜在作用靶(m TOR、JAK3、ACE2、TNFA、AKT2、PIK3CA、MEK1、BRD2、ACE、ANPEP)。分子对接显示,JOL中部分活性化合物对3CLpro和ACE2蛋白具有一定的亲和力。结论JOL可能是通过调节溴结构域包含蛋白2(Brd2)、氨肽酶N(CD13)和ACE2的表达以及干预PI3K/Akt、Jak-STAT、TNF和MAPK信号通路来遏制COVID-19细胞因子风暴的发生和发展,并与3CLpro结合抑制病毒复制,从而有可能对COVID-19有防治作用。
基金supported by National Natural Science Foundation of China (No.61070043)
文摘A primary goal of broadcasting in vehicular ad hoc network (VANET) is to improve the road safety by transmitting alert messages to all surrounding vehicles as soon as possible. In this paper, we adopt the concept of opportunistic routing and propose a multiple candidate relays opportunistic broadcast (MCROB) protocol for VANET. The MCROB protocol is a sender-driven broadcast scheme independent of node density. The packet delivery ratio (PDR) is derived and an expected transmission speed (ETS) for the MCROB is proposed. A priority rule for selecting a proper candidate relay and an adaptive algorithm for forwarding timers of candidate relays are also presented in this paper. Simulations show that MCROB is adaptive to the rapid changing of network conditions. It keeps a low communication overhead introduced by the broadcast and increases the average transmission speed by around 40%.
