An urban traffic ecosystem is a spatial structure composed of air,population,vehicles,roads,green spaces,and regions.Traffic ecological resilience is a critical issue in high-quality urban development.From the perspec...An urban traffic ecosystem is a spatial structure composed of air,population,vehicles,roads,green spaces,and regions.Traffic ecological resilience is a critical issue in high-quality urban development.From the perspective of system optimization,it is important to study the level of urban traffic ecological resilience and analyze its influencing factors.In this study,we evaluated traffic ecological resilience,characterized its spatio-temporal differentiation,and explored its influencing factors by constructing a system of urban traffic ecological resilience and by analyzing the environmental protection and urban construction data in 31 Chinese cities during 2011-2018.By conducting Kernel density analysis,standard deviation ellipse,comprehensive weight determination,panel data regression analysis,andχ2test,we found that traffic ecological resilience was low on the whole and exhibited the temporal trend of“decreasing first and then increasing”and the spatial characteristic of“high in the east,second in the middle,and low in the west”.The cities with high traffic ecological resilience density values were located in Southeast China and tended to move from northwest to southeast.Governance capability,market activity,technological innovation capability,opening degree,and financial resources had significant effects on urban traffic ecological resilience.Finally,we gave some suggestions for improving the urban traffic ecological resilience in Chinese cities as well as other developing countries in the world.展开更多
An efficient and safe gene delivery system remains a challenge in the development of gene therapy.Polycation-based gene nanoparticles are a typical non-viral gene delivery system,which are able to transfect cells in v...An efficient and safe gene delivery system remains a challenge in the development of gene therapy.Polycation-based gene nanoparticles are a typical non-viral gene delivery system,which are able to transfect cells in vitro and in vivo.This paper reported a facile method for constructing biodegradable multilayers via layer-by-layer self-assembly,in which the polycation-based gene nanoparticles were loaded.Through this surface-mediated delivery system,adherent cells on the multilayer could be transfected in situ.Gene nanoparticles-loaded multilayers transfect cells with higher efficiency than naked DNA-loaded multilayers because of the complex configuration of the DNA.DNA nanoparticles/PGA multilayers constructed on the scaffold surface could also realize in situ transfection on the adherent cells.The well-structured,easy-processed multilayers may provide a novel approach to precisely controlled delivery of gene nanoparticles,which may have potential applications for gene therapy in tissue engineering and medical implants.展开更多
文摘An urban traffic ecosystem is a spatial structure composed of air,population,vehicles,roads,green spaces,and regions.Traffic ecological resilience is a critical issue in high-quality urban development.From the perspective of system optimization,it is important to study the level of urban traffic ecological resilience and analyze its influencing factors.In this study,we evaluated traffic ecological resilience,characterized its spatio-temporal differentiation,and explored its influencing factors by constructing a system of urban traffic ecological resilience and by analyzing the environmental protection and urban construction data in 31 Chinese cities during 2011-2018.By conducting Kernel density analysis,standard deviation ellipse,comprehensive weight determination,panel data regression analysis,andχ2test,we found that traffic ecological resilience was low on the whole and exhibited the temporal trend of“decreasing first and then increasing”and the spatial characteristic of“high in the east,second in the middle,and low in the west”.The cities with high traffic ecological resilience density values were located in Southeast China and tended to move from northwest to southeast.Governance capability,market activity,technological innovation capability,opening degree,and financial resources had significant effects on urban traffic ecological resilience.Finally,we gave some suggestions for improving the urban traffic ecological resilience in Chinese cities as well as other developing countries in the world.
基金supported by the National Natural Science Foundation of China(Grant No 50830106)the 863 Programm(Grant No 2006AA03Z329)Science and Technology Plan of Zhejiang Province of China(Grant No 2007C24008)
文摘An efficient and safe gene delivery system remains a challenge in the development of gene therapy.Polycation-based gene nanoparticles are a typical non-viral gene delivery system,which are able to transfect cells in vitro and in vivo.This paper reported a facile method for constructing biodegradable multilayers via layer-by-layer self-assembly,in which the polycation-based gene nanoparticles were loaded.Through this surface-mediated delivery system,adherent cells on the multilayer could be transfected in situ.Gene nanoparticles-loaded multilayers transfect cells with higher efficiency than naked DNA-loaded multilayers because of the complex configuration of the DNA.DNA nanoparticles/PGA multilayers constructed on the scaffold surface could also realize in situ transfection on the adherent cells.The well-structured,easy-processed multilayers may provide a novel approach to precisely controlled delivery of gene nanoparticles,which may have potential applications for gene therapy in tissue engineering and medical implants.
