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农村土质道路路面形态对道路侵蚀的影响 被引量:10
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作者 王天巍 余冰 +1 位作者 刘窑军 李朝霞 《农业工程学报》 EI CAS CSCD 北大核心 2016年第19期162-168,共7页
路面形态作为道路微结构的表现形式,改变道路降雨侵蚀特征,对调节道路系统水沙传递过程有重要意义。本文以拱形、侧向形、平直形、凹形等4种常见路面形态为研究对象,通过室内模拟降雨试验,研究坡度(5°、10°、15°)及路形... 路面形态作为道路微结构的表现形式,改变道路降雨侵蚀特征,对调节道路系统水沙传递过程有重要意义。本文以拱形、侧向形、平直形、凹形等4种常见路面形态为研究对象,通过室内模拟降雨试验,研究坡度(5°、10°、15°)及路形差异下,道路侵蚀特点。结果表明:路形对产沙的影响高于产流,路形通过改变路面径流的水力学特征来改变产沙特性;在坡度10°和15°时,凹形路面径流流态为急流,流速最大,土壤侵蚀率显著高于其他路形,且侵蚀泥沙颗粒粒径较大;在坡度5°和10°时,拱形和平直形路面水流流态为缓流,拱形路面产流产沙能力最弱,抵抗降雨侵蚀的能力最好。凹形和平直形路面对坡度的敏感性较高,随着坡度提升,产沙量和水流能量均有大幅提高,坡度对拱形和侧向形影响较弱。路形差异导致侵蚀特征迥异,在道路设计建设过程中,科学的路形搭配和"路-渠"组合能有效防治道路侵蚀,降低道路建设对生态环境的影响,该研究可为农村低等级道路建设和维护提供参考。 展开更多
关键词 土壤 侵蚀 产流 产沙 土质道路 路面形态 模拟降雨
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Effects of nanofibers on mesenchymal stem cells:environmental factors affecting cell adhesion and osteogenic differentiation and their mechanisms 被引量:3
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作者 Dan YU Jin WANG +2 位作者 Ke-jia QIAN Jing YU Hui-yong ZHU 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2020年第11期871-884,共14页
Nanofibers can mimic natural tissue structure by creating a more suitable environment for cells to grow,prompting a wide application of nanofiber materials.In this review,we include relevant studies and characterize t... Nanofibers can mimic natural tissue structure by creating a more suitable environment for cells to grow,prompting a wide application of nanofiber materials.In this review,we include relevant studies and characterize the effect of nanofibers on mesenchymal stem cells,as well as factors that affect cell adhesion and osteogenic differentiation.We hypothesize that the process of bone regeneration in vitro is similar to bone formation and healing in vivo,and the closer nanofibers or nanofibrous scaffolds are to natural bone tissue,the better the bone regeneration process will be.In general,cells cultured on nanofibers have a similar gene expression pattern and osteogenic behavior as cells induced by osteogenic supplements in vitro.Genes involved in cell adhesion(focal adhesion kinase(FAK)),cytoskeletal organization,and osteogenic pathways(transforming growth factor-β(TGF-β)/bone morphogenic protein(BMP),mitogen-activated protein kinase(MAPK),and Wnt)are upregulated successively.Cell adhesion and osteogenesis may be influenced by several factors.Nanofibers possess certain physical properties including favorable hydrophilicity,porosity,and swelling properties that promote cell adhesion and growth.Moreover,nanofiber stiffness plays a vital role in cell fate,as cell recruitment for osteogenesis tends to be better on stiffer scaffolds,with associated signaling pathways of integrin and Yes-associated protein(YAP)/transcriptional co-activator with PDZ-binding motif(TAZ).Also,hierarchically aligned nanofibers,as well as their combination with functional additives(growth factors,HA particles,etc.),contribute to osteogenesis and bone regeneration.In summary,previous studies have indicated that upon sensing the stiffness of the nanofibrous environment as well as its other characteristics,stem cells change their shape and tension accordingly,regulating downstream pathways followed by adhesion to nanofibers to contribute to osteogenesis.However,additional experiments are needed to identify major signaling pathways in the bone regeneration process,and also to fully investigate its supportive role in fabricating or designing the optimum tissue-mimicking nanofibrous scaffolds. 展开更多
关键词 NANOFIBER Stem cell Mimicking natural tissue Morphology Signaling pathway
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