Autonomous-rail rapid transit(ART)is a new medium-capacity rapid transportation system with punctuality,comfort and convenience,but low-cost construction.Combined velocity planning is a critical approach to meet the r...Autonomous-rail rapid transit(ART)is a new medium-capacity rapid transportation system with punctuality,comfort and convenience,but low-cost construction.Combined velocity planning is a critical approach to meet the requirements of energy-saving and punctuality.An ART velocity pre-planning and re-planning strategy based on the combination of punctuality dynamic programming(PDP)and pseudospectral(PS)method is proposed in this paper.Firstly,the longitudinal dynamics model of ART is established by a multi-particle model.Secondly,the PDP algorithm with global optimal characteristics is adopted as the pre-planning strategy.A model for determining the number of collocation points of the real-time PS method is proposed to improve the energy-saving effect while ensuring computation efficiency.Then the enhanced PS method is utilized to design the velocity re-planning strategy.Finally,simulations are conducted in the typical scenario with sloping roads,traffic lights,and intrusion of the pedestrian.The simulation results indicate that the ART with the proposed velocity trajectory optimization strategy can meet the punctuality requirement,and obtain better economy efficiency compared with the punctuality green light optimal speed advisory(PGLOSA).展开更多
Increasing calls for zero-carbon cities invite transformative solutions for people and places within our cities around the world. Key to the transformation is cities and regions shifting in mobility away from fossil-f...Increasing calls for zero-carbon cities invite transformative solutions for people and places within our cities around the world. Key to the transformation is cities and regions shifting in mobility away from fossil-fuel based car-oriented solutions. The paper investigates a range of case studies where “tram-based boulevards” have been planned or implemented to provide such opportunities. The case studies share a common broader policy objective: to transform the car-oriented or car-saturated areas to an intensified urban template based on a critical presence of dedicated mid-tier transit infrastructure and active transport. “Trams”, or mid-tier, mid-capacity transit when combined with Transit oriented development (TOD) along whole corridors can provide transformative pathways towards zero-carbon outcomes as well as multiple, strong urban benefits. However, many successful or instructive examples of this practice from non-English speaking countries, particularly in Europe, are underdocumented in the international literature. The paper addresses this gap by investigating opportunities and challenges evident in a range of European case studies. These are explored for insight towards policy learning particularly in New World cities seeking to transform into a zero-carbon and more transit-oriented template: How can decision-makers avoid repeating the identified pitfalls, and instead focus on emulating the successful approaches and outcomes? We conclude the need for recognition of the inherent synergies between transport and land use settings in any endeavour, and their translation into policy priorities in both fields of planning. We also conclude the importance of decision makers proactively identifying and critically appraising specific opportunities for change, concerning funding, technology, public opinion, stakeholder alliances or market dynamics, and capitalising on them at suitable moments in time.展开更多
目的研究益气活血复方对脂多糖(LPS)诱导的人脐静脉内皮细胞(HUVECs)Toll样受体4(TLR4)及其下游信号转导通路元件髓样分化因子88(MyD88)、肿瘤坏死因子受体相关因子-6(TRAF-6)、Toll样受体相关分子(TRAM)、Toll样受体相关的干扰素活化子...目的研究益气活血复方对脂多糖(LPS)诱导的人脐静脉内皮细胞(HUVECs)Toll样受体4(TLR4)及其下游信号转导通路元件髓样分化因子88(MyD88)、肿瘤坏死因子受体相关因子-6(TRAF-6)、Toll样受体相关分子(TRAM)、Toll样受体相关的干扰素活化子(TRIF)表达的影响,探讨益气活血复方含药血清防治动脉粥样硬化(AS)的机制。方法选择新西兰大耳白兔20只,随机分为4组,即正常组、中药高浓度组、中药中浓度组、中药低浓度组,每组5只。以上各组白兔分别以生理盐水和高、中、低浓度益气活血复方连续灌胃7d。末次灌胃给药2h后,心脏采血,离心后分离血清。体外培养人脐静脉内皮细胞,用LPS刺激后,分别加入高、中、低浓度益气活血复方含药血清干预24h,收集细胞,用Real ti me PCR方法测定TLR4、MyD88、TRAF-6、TRAM及TRIF mRNA的表达。结果用LPS刺激人脐静脉内皮细胞后,引起TLR4、MyD88、TRAF-6、TRAM及TRIF mRNA的高表达(与空白对照组比较,P<0.01),用益气活血复方含药血清干预以后显著抑制TLR4、MyD88及TRAF-6 mRNA的高表达(与模型组比较P<0.05或P<0.01),对TRAM及TRIF作用不明显。结论益气活血复方可阻断TLR4高表达,同时阻断TLR4胞内信号转导的MyD88依赖性途径,而对MyD88非依赖性途径作用不明显,因此益气活血复方主要是通过阻断MyD88依赖性途径来发挥其抗动脉粥样硬化的作用。展开更多
基金Supported by National Natural Science Foundation of China(Grant Nos.52072073 and 52025121)National Key R&D Program of China(Grant No.2018YFB1201602).
文摘Autonomous-rail rapid transit(ART)is a new medium-capacity rapid transportation system with punctuality,comfort and convenience,but low-cost construction.Combined velocity planning is a critical approach to meet the requirements of energy-saving and punctuality.An ART velocity pre-planning and re-planning strategy based on the combination of punctuality dynamic programming(PDP)and pseudospectral(PS)method is proposed in this paper.Firstly,the longitudinal dynamics model of ART is established by a multi-particle model.Secondly,the PDP algorithm with global optimal characteristics is adopted as the pre-planning strategy.A model for determining the number of collocation points of the real-time PS method is proposed to improve the energy-saving effect while ensuring computation efficiency.Then the enhanced PS method is utilized to design the velocity re-planning strategy.Finally,simulations are conducted in the typical scenario with sloping roads,traffic lights,and intrusion of the pedestrian.The simulation results indicate that the ART with the proposed velocity trajectory optimization strategy can meet the punctuality requirement,and obtain better economy efficiency compared with the punctuality green light optimal speed advisory(PGLOSA).
文摘Increasing calls for zero-carbon cities invite transformative solutions for people and places within our cities around the world. Key to the transformation is cities and regions shifting in mobility away from fossil-fuel based car-oriented solutions. The paper investigates a range of case studies where “tram-based boulevards” have been planned or implemented to provide such opportunities. The case studies share a common broader policy objective: to transform the car-oriented or car-saturated areas to an intensified urban template based on a critical presence of dedicated mid-tier transit infrastructure and active transport. “Trams”, or mid-tier, mid-capacity transit when combined with Transit oriented development (TOD) along whole corridors can provide transformative pathways towards zero-carbon outcomes as well as multiple, strong urban benefits. However, many successful or instructive examples of this practice from non-English speaking countries, particularly in Europe, are underdocumented in the international literature. The paper addresses this gap by investigating opportunities and challenges evident in a range of European case studies. These are explored for insight towards policy learning particularly in New World cities seeking to transform into a zero-carbon and more transit-oriented template: How can decision-makers avoid repeating the identified pitfalls, and instead focus on emulating the successful approaches and outcomes? We conclude the need for recognition of the inherent synergies between transport and land use settings in any endeavour, and their translation into policy priorities in both fields of planning. We also conclude the importance of decision makers proactively identifying and critically appraising specific opportunities for change, concerning funding, technology, public opinion, stakeholder alliances or market dynamics, and capitalising on them at suitable moments in time.
文摘目的研究益气活血复方对脂多糖(LPS)诱导的人脐静脉内皮细胞(HUVECs)Toll样受体4(TLR4)及其下游信号转导通路元件髓样分化因子88(MyD88)、肿瘤坏死因子受体相关因子-6(TRAF-6)、Toll样受体相关分子(TRAM)、Toll样受体相关的干扰素活化子(TRIF)表达的影响,探讨益气活血复方含药血清防治动脉粥样硬化(AS)的机制。方法选择新西兰大耳白兔20只,随机分为4组,即正常组、中药高浓度组、中药中浓度组、中药低浓度组,每组5只。以上各组白兔分别以生理盐水和高、中、低浓度益气活血复方连续灌胃7d。末次灌胃给药2h后,心脏采血,离心后分离血清。体外培养人脐静脉内皮细胞,用LPS刺激后,分别加入高、中、低浓度益气活血复方含药血清干预24h,收集细胞,用Real ti me PCR方法测定TLR4、MyD88、TRAF-6、TRAM及TRIF mRNA的表达。结果用LPS刺激人脐静脉内皮细胞后,引起TLR4、MyD88、TRAF-6、TRAM及TRIF mRNA的高表达(与空白对照组比较,P<0.01),用益气活血复方含药血清干预以后显著抑制TLR4、MyD88及TRAF-6 mRNA的高表达(与模型组比较P<0.05或P<0.01),对TRAM及TRIF作用不明显。结论益气活血复方可阻断TLR4高表达,同时阻断TLR4胞内信号转导的MyD88依赖性途径,而对MyD88非依赖性途径作用不明显,因此益气活血复方主要是通过阻断MyD88依赖性途径来发挥其抗动脉粥样硬化的作用。
