Usually, the collapsible loess widely distributed across the world can serve as a type of foundation soil that meets its strength requirement after dense compaction and elimination of collapsibility. However, many pro...Usually, the collapsible loess widely distributed across the world can serve as a type of foundation soil that meets its strength requirement after dense compaction and elimination of collapsibility. However, many problems such as cracks and differential settlement still occur in loess roads in the seasonally frozen ground regions after several years of op- eration. Many studies have demonstrated that these secondary or multiple collapses primarily result from the repeated freezing-thawing, wetting-drying, and salinization-desalinization cycles. Therefore, we conducted a research program to （1） monitor the in-situ ground temperatures and water content in certain loess roads to understand their changes, （2） study the effects of freezing-thawing, wetting-drying, and salinization-desalinization cycles on geotechnical properties and micro-fabrics of compacted loess in the laboratory, and （3） develop mitigative measures and examine their engineered effectiveness, i.e., their thermal insulating and water-proofing effects in field and laboratory tests. Our results and advances are reviewed and some further research needs are proposed. These findings more clearly explain the processes and mechanisms of secondary and multiple collapse of loess roads. We also offer references for further study of the weakening mechanisms of similar structural soils.展开更多
Concentration time-histories of H20 were measured behind reflected shock waves during hydrogen combustion. Experiments were conducted at temperatures of 1117-1282 K, the equivalence ratios of 0.5 and 0.25, and a press...Concentration time-histories of H20 were measured behind reflected shock waves during hydrogen combustion. Experiments were conducted at temperatures of 1117-1282 K, the equivalence ratios of 0.5 and 0.25, and a pressure at 2 atm using a mixture of H2/O2 highly diluted with argon. H2O was monitored using tunable mid-infrared diode laser absorption at 2.55 μm （3920.09 cm-1）. These time-histories provide kinetic targets to test and refine reaction mechanisms for hydrogen. Comparisons were made with the predictions of four detailed kinetic mechanisms published in the last four years. Such comparisons of H2O concentration profiles indicate that the AramcoMech 2.0 mechanism yields the best agreement with the experimental data, while CRECK, San Diego, and HP-Mech mechanisms show significantly poor predictions. Reaction pathway analysis for hydrogen oxidation indicates that the reaction H ＋ OH ＋ M = H20 ＋ M is the key reaction for controlling the H2O formation by hydrogen oxidation. It is inferred that the discrepancy of the conversion percentage from H to H20 among these four mechanisms induces the difference of performance on H2O time-history predictions. This work demonstrates the potential of time-history measurement for validation of large reaction mechanisms.展开更多
目的:基于网络药理学方法筛选固本平喘剂(补骨脂、地龙、防风)中的主要活性成分,探讨其治疗支气管哮喘的作用机制。方法:通过中药系统药理学数据库TCMSP数据库、中药与化学成分数据库,筛选固本平喘剂的活性成分及靶标。利用Genecards、O...目的:基于网络药理学方法筛选固本平喘剂(补骨脂、地龙、防风)中的主要活性成分,探讨其治疗支气管哮喘的作用机制。方法:通过中药系统药理学数据库TCMSP数据库、中药与化学成分数据库,筛选固本平喘剂的活性成分及靶标。利用Genecards、OMIM数据库获得支气管哮喘的潜在靶标基因。将两者靶基因进行映射后通过Cytoscape3.6.1软件构建“成分-靶标”网络、结合String数据库构建蛋白质相互作用网络扩充核心靶点。依托功能注释生物信息学分析平台DAVID数据库对固本平喘剂的作用靶点进行基因本体(gene ontology,GO)生物学过程和基因组百科全书(kyoto encyclopedia of genes and genomes,KEGG)通路富集注释分析,通过Autodock vina软件进行分子对接以验证结果。结果:符合筛选条件的共有53个活性成分,补骨脂18个,地龙17个,防风18个,筛选得到固本平喘剂关键成分,包括补骨脂黄酮类、补骨脂查耳酮类、汉黄芩素、补骨脂酚、β-谷甾醇等;通过GenCards、OMIM数据库剔除重复后,共收集支气管哮喘潜在靶点2358个。将固本平喘剂和支气管哮喘靶点进行映射取交集共得到237个交叉靶点,即固本平喘剂治疗支气管哮喘潜在作用靶点。以degree值大于二倍均值的靶点为PTGS2、ESR1、ACHE、ESR2、PTGS1、DPP4、ADORA3,degree值排名前5的靶蛋白为PIK3CA、MAPK3、MAPK1、TP53、AKT1。主要涉及PI3K-Akt信号通路、TNF信号通路、趋化因子信号通路、FoxO信号通路、MAPK信号通路、Toll样受体信号通路、T细胞受体信号通路等。结论:固本平喘剂治疗支气管哮喘潜在作用靶点有PTGS2、ESR1、ACHE、ESR2、PTGS1、DPP4、ADORA3、PIK3CA、MAPK3、MAPK1、TP53、AKT1,可能通过抗感染、调节免疫、抑制气道重塑等发挥作用。展开更多
基金supported by the National Key Basic Research Program of China (973 Program) (No. 2012CB026106)the Science and Technology Major Project of Gansu Province (No. 143GKDA007)+2 种基金the West Light Foundation of CAS for Dr. G. Y. Lithe Program for Innovative Research Group of the Natural Science Foundation of China (No. 41121061)the Foundation of the State Key Laboratory of Frozen Soils Engineering of CAS (No. SKLFSE-ZT-11)
文摘Usually, the collapsible loess widely distributed across the world can serve as a type of foundation soil that meets its strength requirement after dense compaction and elimination of collapsibility. However, many problems such as cracks and differential settlement still occur in loess roads in the seasonally frozen ground regions after several years of op- eration. Many studies have demonstrated that these secondary or multiple collapses primarily result from the repeated freezing-thawing, wetting-drying, and salinization-desalinization cycles. Therefore, we conducted a research program to （1） monitor the in-situ ground temperatures and water content in certain loess roads to understand their changes, （2） study the effects of freezing-thawing, wetting-drying, and salinization-desalinization cycles on geotechnical properties and micro-fabrics of compacted loess in the laboratory, and （3） develop mitigative measures and examine their engineered effectiveness, i.e., their thermal insulating and water-proofing effects in field and laboratory tests. Our results and advances are reviewed and some further research needs are proposed. These findings more clearly explain the processes and mechanisms of secondary and multiple collapse of loess roads. We also offer references for further study of the weakening mechanisms of similar structural soils.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2017YFB0202400 and 2017YFB0202401)
文摘Concentration time-histories of H20 were measured behind reflected shock waves during hydrogen combustion. Experiments were conducted at temperatures of 1117-1282 K, the equivalence ratios of 0.5 and 0.25, and a pressure at 2 atm using a mixture of H2/O2 highly diluted with argon. H2O was monitored using tunable mid-infrared diode laser absorption at 2.55 μm （3920.09 cm-1）. These time-histories provide kinetic targets to test and refine reaction mechanisms for hydrogen. Comparisons were made with the predictions of four detailed kinetic mechanisms published in the last four years. Such comparisons of H2O concentration profiles indicate that the AramcoMech 2.0 mechanism yields the best agreement with the experimental data, while CRECK, San Diego, and HP-Mech mechanisms show significantly poor predictions. Reaction pathway analysis for hydrogen oxidation indicates that the reaction H ＋ OH ＋ M = H20 ＋ M is the key reaction for controlling the H2O formation by hydrogen oxidation. It is inferred that the discrepancy of the conversion percentage from H to H20 among these four mechanisms induces the difference of performance on H2O time-history predictions. This work demonstrates the potential of time-history measurement for validation of large reaction mechanisms.
文摘目的:基于网络药理学方法筛选固本平喘剂(补骨脂、地龙、防风)中的主要活性成分,探讨其治疗支气管哮喘的作用机制。方法:通过中药系统药理学数据库TCMSP数据库、中药与化学成分数据库,筛选固本平喘剂的活性成分及靶标。利用Genecards、OMIM数据库获得支气管哮喘的潜在靶标基因。将两者靶基因进行映射后通过Cytoscape3.6.1软件构建“成分-靶标”网络、结合String数据库构建蛋白质相互作用网络扩充核心靶点。依托功能注释生物信息学分析平台DAVID数据库对固本平喘剂的作用靶点进行基因本体(gene ontology,GO)生物学过程和基因组百科全书(kyoto encyclopedia of genes and genomes,KEGG)通路富集注释分析,通过Autodock vina软件进行分子对接以验证结果。结果:符合筛选条件的共有53个活性成分,补骨脂18个,地龙17个,防风18个,筛选得到固本平喘剂关键成分,包括补骨脂黄酮类、补骨脂查耳酮类、汉黄芩素、补骨脂酚、β-谷甾醇等;通过GenCards、OMIM数据库剔除重复后,共收集支气管哮喘潜在靶点2358个。将固本平喘剂和支气管哮喘靶点进行映射取交集共得到237个交叉靶点,即固本平喘剂治疗支气管哮喘潜在作用靶点。以degree值大于二倍均值的靶点为PTGS2、ESR1、ACHE、ESR2、PTGS1、DPP4、ADORA3,degree值排名前5的靶蛋白为PIK3CA、MAPK3、MAPK1、TP53、AKT1。主要涉及PI3K-Akt信号通路、TNF信号通路、趋化因子信号通路、FoxO信号通路、MAPK信号通路、Toll样受体信号通路、T细胞受体信号通路等。结论:固本平喘剂治疗支气管哮喘潜在作用靶点有PTGS2、ESR1、ACHE、ESR2、PTGS1、DPP4、ADORA3、PIK3CA、MAPK3、MAPK1、TP53、AKT1,可能通过抗感染、调节免疫、抑制气道重塑等发挥作用。
