Effect of acitretin on the T helper cells of psoriasis vulgaris

Objective To investigate the effects of acitretin on T helper cell (Th) 1/Th2 balance and Th17 cells in psoriasis vulgaris (PV) patients. Methods A total of 13 men and 17 women with PV were investigated. 10 mg of acitretin was administered twice a day for 8 weeks for intervention therapy. Serum levels of interferon-gamma (IFN-γ), interleukin (IL)-4 and IL-17 were measured by enzyme-linked immunosorbent assay. T, Th1, Th2 and Th17 cells in skin biopsies were counted with double-labeled immunofluorescence. Psoriasis Area and Severity Index (PASI) score was calculated before and 8 weeks after treatment. Results Before treatment PV patients had higher serum levels of IFN-γ and IL-17, and increased T, Th1 and Th17 cells in skin biopsies. After treatment, both serum levels of IFN-γ and IL-17, and T, Th1 and Th17 cells infiltrating in PV skin decreased significantly. Th1/Th2 balance was restored to normal. However, their IL-4 and Th2 cells showed no significant change throughout the therapy. Conclusion Acitretin exerts influence on dermal Th1/Th2 balance and Th17 cell infiltration, so does it on production of systematic inflammatory cytokines IFN-γ and IL-17 in PV patients. However, Th2 cells and its derivative cytokine-IL-4 are not affected.     

三峡库区周期性库水位变化对抗滑桩加固效果非饱和流固耦合分析

三峡库区内广泛发育的滑坡等地质灾害在水库运行水位周期性波动条件下会发生复活乃至失稳。抗滑桩是其中应用广泛、效果良好的防治措施之一。抗滑桩在库水位周期性波动条件下对滑坡的治理加固效果及其自身的变形受力特征是较为重要但研究尚少的问题。采用非饱和岩土本构关系,考虑在库水位周期性波动条件下滑坡体处于饱和-非饱和周期性变化时的流固耦合效应,采用有限元法对设置抗滑桩前后库区某滑坡的位移和稳定状态进行模拟,并分析了抗滑桩内力及其桩顶位移随库水位变化的特征。研究结果表明,抗滑桩对滑坡的水平位移控制效果较为显著,安全系数最少能提高到2以上。在库水位运行的一个周期内,抗滑桩加固滑坡的安全系数变化幅度不超过5.4 %,而抗滑桩内力及桩顶位移不超过10.4 %。滑坡最小安全系数和抗滑桩最大受力出现在最高水位时,其变化趋势与水位变化趋势较为一致。     

基于有限元法的小水线面双体船结构优化

小水线面双体船结构复杂,需要有效的工具对其进行优化设计,在满足强度刚度要求的情况下控制结构重量.本文利用优化软件Altair.OptiStruct、Msc.Nastran、iSIGHT对一艘小水线面双体船结构进行了尺寸优化、形状优化、和拓扑优化.结构优化基于有限元法完成,以结构重量作为目标函数,结构应力作为约束条件.优化结果表明,通过选择适当的设计变量,能够在结构应力不超过规定上限的条件下使结构重量显著降低并达到最小值.     

大型桥梁健康监测系统中2种数据通信技术的应用及比较

Lonworks现场总线技术和基于TCP/IP的局域网(LAN)技术是目前用于构建桥梁健康监测系统的数据通信系统最为主流的2种技术.对这2项技术的原理进行了分析,并探讨了其在桥梁健康监测系统中的应用.     

陕北地区低湿条件下混凝土碳化深度及影响因素研究

为深入分析导致混凝土碳化的各类因素,降低碳化的破坏作用,通过对陕北地区低湿条件下几座隧道的二次衬砌,桥梁的桥墩、承台、桥台的碳化深度进行测试,分析低湿环境下混凝土强度、龄期、光照、结构物位置与碳化深度的关系,得到适合该地区的碳化深度预测公式xc=0.312 51t和y=0.103t0.713。在降低混凝土碳化的不利影响方面,通过隔绝空气以及调整混凝土配合比,可以保证在密实度得到改善的混凝土中建立一个适度的高碱环境,以减少或避免碳化对混凝土耐久性的破坏。     

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北京2008年奥运会期间,北京市采取了一系列奥运交通保障措施,交叉口公交信号优先是其中重要的一项内容。本文首先介绍了交叉口公交优先和紧急优先的控制逻辑和控制策略,然后讲述了奥体中心区利用射频技术进行交叉口公交车信号优先和奥运VIP车辆信号紧急优先的实现方式和实现过程,简述了海信信号机公交优先和紧急优先信号配置方法;最后,对奥体中心区公交优先和紧急优先的实施效果进行了总结和评价,并给出了城市公交信号优先方面的几点建议。     

美国城市交通模型立法的历史背景

中国近年来经济快速增长,带来了全面性的城市交通建设.在促进经济发展和社会进步的同时,中国城市交通的发展正面临着许多挑战.如何有效地评估适应新挑战的交通政策措施,并确保交通政策的妥善执行,是中国相关政府部门刻不容缓的课题.通过对已有50年经验的美国运输规划与交通需求预测程序相关立法资料的整理,认为包括数据收集、数据分析、交通需求预测以及替代方法评估的城市交通规划程序可以有效地协助政府部门与专家面对这些新兴的挑战.同时指出,一个定期修订以反映社会发展变化的全国交通建设与发展法,可规范一定比例的资金预算,规定城市交通规划程序与执行的规划组织,并要求制定人员培训计划以有效地执行交通政策.     

A constraint programming model with time uncertainty for cooperative flight departures

The lack of a proper integration of strategic Air Traffic Management decision support tools with tactical Air Traffic Control interventions usually generates a negative impact on the Reference Business Trajectory adherence, and in consequence affects the potential of the Trajectory-Based Operations framework. In this paper, a new mechanism relaying on Reference Business Trajectories as a source of data to reduce the amount of Air Traffic Controller interventions at the tactical level while preserving Air Traffic Flow Management planned operations is presented. Artificial Intelligence can enable Constraint Programming as it is a powerful paradigm for solving complex, combinatorial search problems. The proposed methodology takes advantage of Constraint Programming and fosters adherence of Airspace User’s trajectory preferences by identifying tight interdependencies between trajectories and introducing a new mechanism to improve the aircraft separation at concurrence events considering time uncertainty. The underlying philosophy is to capitalize present degrees of freedom between layered Air Traffic Management planning tools, when sequencing departures at the airports by considering the benefits of small time stamp changes in the assigned Calculated Take-Off Time departures and to enhance Trajectory-Based Operations concepts.     

通州湾港区高滩围堤设计关键技术

通州湾港区位于南通市腰沙、冷家沙区域,地处辐射沙洲南缘,低潮时滩面出露,潮差大.通州湾港区规划方案体量巨大,需通过大面积围填高滩形成港区陆域,围堤建设是陆域形成的前提条件.通过研究波浪、潮流、地质等基础资料,结合模型试验和工程实践,从堤顶高程、堤心材料、抗滑防渗防冲刷分析、施工要点等多方面进行研究、总结大潮差粉砂底质环境下高滩围堤设计的关键技术,为后续工程提供参考、积累经验.     

厦门港嵩屿港区潮流特性物理模型试验

厦门港嵩屿规划港区位于两股潮汐水流分流、汇流处,水流流态复杂导致规划码头岸线前沿水域存在缓流区和回流区。涨、落潮流态对港区平面布置十分敏感。岸线方案如不能满足两股水流的分流要求,将在码头前沿水域产生大尺度回流区或导致泥沙严重回淤。进行24组物理模型试验,确定嵩屿港区布置方案。现场实测资料表明,物模试验成果能较好地预测嵩屿港区建成后的水流条件。