An amphiphilic conjugate approach toward the design and synthesis of betulinic acid-polyphenol conjugates as inhibitors of the HIV-1 gp41 fusion core formation

Exploration of potent inhibitors of the HIV-1 gp41 fusion core formation is a promising strategy to discover small-molecule HIV-1 entry inhibitors for the treatment of HIV-1 infection. In this paper, a series of novel betulinic acid-polyphenol conjugates was designed, guided by molecular modeling of the binding of betulinic acid (BA) and phenolic galloyl/caffeoyl groups in the groove on the gp41 N-terminal heptad repeat (NHR) trimeric coiled coil. These conjugates were synthesized via conjugation of galloyl and caffeoyl groups with BA at the C-28 position. Their inhibitory activities of HIV gp41 six-helix bundle (6-HB) formation between the NHR peptide N36 and the C-terminal heptad repeat (CHR) peptide C34 were evaluated with size-exclusion HPLC. Conjugates bearing a galloyl group were found to exhibit four to sixfold higher inhibitory activities than that of parent compound BA, suggesting that they may be exploitable as HIV-1 fusion/entry inhibitors targeting gp41. The docking study on BA and its derivatives suggests that hydrophobic and hydrogen-bonding pockets exist in the groove of the gp41 NHR trimeric coiled coil and that a potent inhibitor should have amphiphilic structures to cooperatively interact with both pockets. This possibility was explored by incorporating both lipophilic and hydrophilic groups into the conjugates in a well-defined orientation to bind with both pockets in the gp41 NHR-trimer.     

一种面向车辆实时数据并行处理的任务调度算法

车辆实时监管正面临着不断增长的大规模车辆监测数据的实时处理需求,需要采用分布式的并行计算架构来提升大规模车辆监测数据处理的性能,支撑多样化的车辆监测数据处理任务,应对支撑环境的伸缩性需求。在这种架构下,对系统中不同计算节点间的车辆监测数据处理任务的调度提出了更高的要求。针对这一要求,并结合流式到达及历史积累的车辆监测数据的持续化处理需求以及大规模车辆监测数据实时处理中内存敏感的特征,提出一种基于路由表的并行任务调度算法。该算法基于车辆监测数据时空属性以及各计算节点的内存信息建立路由表,并以路由表的形式来进行任务的并行划分和分配调度,从而使得各计算节点达到负载均衡的状态。实验表明该算法能够使计算节点间的负载差异缩小到12%以内。此外,该算法在某市车辆监管实时系统中的实际应用也证明了其有效性。     

基于极端梯度提升的PEMFC长短期老化趋势预测

为了同时实现准确的燃料电池长短期老化趋势预测,提出基于极端梯度提升（XGBoost）的PEMFC老化趋势预测模型。首先,对燃料电池老化实验数据进行降噪预处理,利用双指数对电压恢复特性进行建模;然后,基于XGBoost算法,构建4种提前多步短期老化预测模型以及考虑恢复性的长期预测策略,并利用粒子群算法优化模型的参数;最后,比较4种短期预测模型的预测结果,并将最优的预测模型应用于长期老化预测策略。典型数据实验表明：采用多输入多输出策略（MIMO）的XGBoost预测模型具有最好的预测性能,其提前3步预测的均方根误差为0.00465、平均相对误差为0.00219平均运算时间为3.48 s;基于MIMO-XGBoost且考虑恢复性的长期预测策略剩余使用寿命（RUL）的平均相对误差为7.74%,显著优于自回归差分移动平均方法。     

SEM IPS10型图像分析仪测量晶体粒径

ＳＥＭＩＰＳ１０ 型图像分析仪系统可以自动、准确地测量晶体等目标的尺寸,对大量测量数据进行统计计算,求出平均直径、标准偏差等,并绘制晶体粒径分布直方图。     

间位芳纶纸板的制备及性能研究

采用间位芳纶短切纤维和沉析纤维为原材料制备了芳纶纸板,分析了纤维配比、温度及压强对纸板电气强度及拉伸性能的影响,并对纸板金属离子含量、水浸液电导率和p H值、耐油污性能等进行了研究。结果表明:间位芳纶纸板最佳的纤维配比为短切纤维∶沉析纤维=5∶5,最佳工艺是热压温度280℃、热压压强8 MPa。间位芳纶纸板的综合性能达到国外同类产品水平,具有良好的应用前景。     

支持高并发数据流处理的MapReduce中间结果缓存

针对面向大规模历史数据的高并发数据流处理需求,为改进MapReduce的实时处理能力,提出了一种内存Hash B树、外存SSTable文件的keyvalue中间结果缓存,该结构具有可划分性、可扩展性和高效性.在此基础上,利用B树的平衡性特征提出了一种基于概率的B树构造算法和多路查询算法,利用读写开销估算和缓冲区信息改造了外存文件读写策略和内外存替换算法,进一步优化了中间结果的高并发读写性能.算法分析和实验证明了该缓存的有效性.     

事件驱动的微服务调用链路数据动态采集方法

微服务调用链路数据是微服务应用系统日常运行中产生的一类重要数据,它以链路形式记录了微服务应用中一次用户请求对应的一系列服务调用信息。由于系统的分布性,微服务调用链路数据产生在不同的微服务部署节点,当前对这些分布数据的采集一般采用全量采集和采样采集两种方法。全量采集会产生较大数据传输和数据存储等成本,而采样采集则可能会漏掉关键的链路数据。因此,提出一种基于事件驱动和流水线采样的微服务调用链路数据动态采集方法,并基于开源软件Zipkin设计实现了一个微服务调用链路数据动态采集系统。该系统首先对不同节点符合预定义事件特征的链路数据进行流水线采样,即数据采集服务端只在某节点产生事件定义的数据时对所有节点采集同一链路数据;同时,针对不同节点的数据产生速率不一致问题,采用基于时间窗口的多线程流式数据处理和数据同步技术实现不同节点的数据采集和传递;最后,针对各节点链路数据到达服务端先后顺序不一的问题,通过时序对齐方式进行全链路数据的同步和汇总。在公开的微服务调用链路数据集上的实验结果表明,相较于全量采集和采样采集方法,所提方法对于包含异常、慢响应等特定事件的链路数据具有采集准确性高、效率好的效果。     

Rheological behaviors and processing windows of low viscosity epoxy resin for VIMP

The chemorheological behaviors of a low viscosity epoxy resin system (Huntsman 1564/3486) for vacuum infusion moulding process (VIMP) were studied with viscosity experiments.The dual-Arrhenius rheological model and the engineering viscosity model were established and compared with the experimental data.The result showed that the viscosity in the earlier stage calculated by dual-Arrhenius model were smaller than the experimental data,while the data calculated by the engineering model were larger.Combining the two models together can predict the rheological behaviors of the resin system in a more credible manner.The processing windows of the resin system for VIMP were determined based on the two models.The optimum processing temperature is 30-45 ℃.