Human induced pluripotent stem cells(hiPSCs)are invaluable resources for producing high-quality differentiated cells in unlimited quantities for both basic research and clinical use.They are particularly useful for st...Human induced pluripotent stem cells(hiPSCs)are invaluable resources for producing high-quality differentiated cells in unlimited quantities for both basic research and clinical use.They are particularly useful for studying human disease mechanisms in vitro by making it possible to circumvent the ethical issues of human embryonic stem cell research.However,significant limitations exist when using conventional flat culturing methods especially concerning cell expansion,differentiation efficiency,stability maintenance and multicellular 3D structure establishment,differentiation prediction.Embryoid bodies(EBs),the multicellular aggregates spontaneously generated from iPSCs in the suspension system,might help to address these issues.Due to the unique microenvironment and cell communication in EB structure that a 2D culture system cannot achieve,EBs have been widely applied in hiPSC-derived differentiation and show significant advantages especially in scaling up culturing,differentiation efficiency enhancement,ex vivo simulation,and organoid establishment.EBs can potentially also be used in early prediction of iPSC differentiation capability.To improve the stability and feasibility of EB-mediated differentiation and generate high quality EBs,critical factors including iPSC pluripotency maintenance,generation of uniform morphology using micro-pattern 3D culture systems,proper cellular density inoculation,and EB size control are discussed on the basis of both published data and our own laboratory experiences.Collectively,the production of a large quantity of homogeneous EBs with high quality is important for the stability and feasibility of many PSCs related studies.展开更多
Gully erosion,an integrated result of various social and environmental factors,is a severe problem for sustainable development and ecology security in southern China.Cur-rently,the dominant driving forces on gully dis...Gully erosion,an integrated result of various social and environmental factors,is a severe problem for sustainable development and ecology security in southern China.Cur-rently,the dominant driving forces on gully distribution are shown to vary at different spatial scales.However,few systematic studies have been performed on spatial scaling effects in identifying driving forces for gully erosion.In this study,we quantitatively identified the de-terminants of gully distribution and their relative importance at four different spatial scales(southern China,Jiangxi province,Ganxian county,and Tiancun township,respectively)based on the Boruta algorithm.The optimal performance of gully susceptibility mapping was investigated by comparing the performance of the multinomial logistic regression(MLR),lo-gistic model tree(LMT),and random forest(RF).Across the four spatial scales,the total contributions of gully determinants were classified as lithology and soil(32.65%)≥topogra-phy(22.40%)>human activities(22.31%)>climate(11.32%)>vegetation(11.31%).Among these factors,precipitation(7.82%),land use and land cover(6.16%),rainfall erosivity(10.15%),and elevation(11.59%)were shown to be the predominant factors for gully erosion at the individual scale of southern China,province,county,and township,respectively.In addition,contrary to climatic factors,the relative importance of soil properties and vegetation increased with the decrease of spatial scale.Moreover,the RF model outperformed MLR and LMT at all the investigated spatial scales.This study provided a reference for factor selection in gully susceptibility modeling and facilitated the development of gully erosion management strategies suitable for different spatial scales.展开更多
基金Supported by National Natural Science Foundation of China,No.81770621,No.81573053Ministry of Education,Culture,Sports,Science,and Technology of Japan,KAKENHI,No.16K15604,No.18H02866Natural Science Foundation of Jiangsu Province,No.BK20180281
文摘Human induced pluripotent stem cells(hiPSCs)are invaluable resources for producing high-quality differentiated cells in unlimited quantities for both basic research and clinical use.They are particularly useful for studying human disease mechanisms in vitro by making it possible to circumvent the ethical issues of human embryonic stem cell research.However,significant limitations exist when using conventional flat culturing methods especially concerning cell expansion,differentiation efficiency,stability maintenance and multicellular 3D structure establishment,differentiation prediction.Embryoid bodies(EBs),the multicellular aggregates spontaneously generated from iPSCs in the suspension system,might help to address these issues.Due to the unique microenvironment and cell communication in EB structure that a 2D culture system cannot achieve,EBs have been widely applied in hiPSC-derived differentiation and show significant advantages especially in scaling up culturing,differentiation efficiency enhancement,ex vivo simulation,and organoid establishment.EBs can potentially also be used in early prediction of iPSC differentiation capability.To improve the stability and feasibility of EB-mediated differentiation and generate high quality EBs,critical factors including iPSC pluripotency maintenance,generation of uniform morphology using micro-pattern 3D culture systems,proper cellular density inoculation,and EB size control are discussed on the basis of both published data and our own laboratory experiences.Collectively,the production of a large quantity of homogeneous EBs with high quality is important for the stability and feasibility of many PSCs related studies.
基金National Natural Science Foundation of China,No.42277329,No.41807065,No.42077067China Postdoctoral Science Foundation,No.2018M640714Fundamental Research Funds for the Central Universities,No.2662021ZHQD003。
文摘Gully erosion,an integrated result of various social and environmental factors,is a severe problem for sustainable development and ecology security in southern China.Cur-rently,the dominant driving forces on gully distribution are shown to vary at different spatial scales.However,few systematic studies have been performed on spatial scaling effects in identifying driving forces for gully erosion.In this study,we quantitatively identified the de-terminants of gully distribution and their relative importance at four different spatial scales(southern China,Jiangxi province,Ganxian county,and Tiancun township,respectively)based on the Boruta algorithm.The optimal performance of gully susceptibility mapping was investigated by comparing the performance of the multinomial logistic regression(MLR),lo-gistic model tree(LMT),and random forest(RF).Across the four spatial scales,the total contributions of gully determinants were classified as lithology and soil(32.65%)≥topogra-phy(22.40%)>human activities(22.31%)>climate(11.32%)>vegetation(11.31%).Among these factors,precipitation(7.82%),land use and land cover(6.16%),rainfall erosivity(10.15%),and elevation(11.59%)were shown to be the predominant factors for gully erosion at the individual scale of southern China,province,county,and township,respectively.In addition,contrary to climatic factors,the relative importance of soil properties and vegetation increased with the decrease of spatial scale.Moreover,the RF model outperformed MLR and LMT at all the investigated spatial scales.This study provided a reference for factor selection in gully susceptibility modeling and facilitated the development of gully erosion management strategies suitable for different spatial scales.
