The climate paleogeography,especially the climate classifications,helps to interpret the global and regional climate changes and intuitively compare the climate conditions in different regions.However,the application ...The climate paleogeography,especially the climate classifications,helps to interpret the global and regional climate changes and intuitively compare the climate conditions in different regions.However,the application of climate classification in deep time(i.e.,climate paleogeography)is prohibited due to the usually qualitatively constrained paleoclimate and the inconsistent descriptions and semantic heterogeneity of the climate types.In this study,a climate paleogeography knowledge graph is established under the framework of the Deep-Time Digital Earth program(DDE).The hierarchical knowledge graph consists of five paleoclimate classifications based on various strategies.The classifications are described and their strengths and weaknesses are fully evaluated in four aspects:“simplicity,applicability,quantifiability,and comparability”.We also reconstruct the global climate distributions in the Late Cretaceous according to these classifications.The results are compared and the relationships among these climate types in different classifications are evaluated.Our study unifies scientific concepts from different paleoclimate classifications,which provides an important theoretical basis for the application of paleoclimate classifications in deep time.展开更多
This study was designed to establish a strategy for the extraction,purification,and structure analysis of chondroitin sulfate(cs)in milligram amounts.Crude acidic polysaccharides were extracted from six kinds of marin...This study was designed to establish a strategy for the extraction,purification,and structure analysis of chondroitin sulfate(cs)in milligram amounts.Crude acidic polysaccharides were extracted from six kinds of marine animals by enzymatic hydrolysis and hexadecylpyridinium chloride precipitation and purified by Q Sepharose Fast Flow strong anion exchange column.The purification of each crude polysaccharide was completed within 1 h.The structure of the polysaccharides,i.e.their chemical characterization,functional group,molecular weight and monosaccharide composition,were analyzed by colorimetry,nuclear magnetic resonace and high-performance liquid chromatogrpahy,respectively.All polysaccharides were identified as Cs.The oligosaccharide profile produced by enzyme hydrolysis of polysaccharides was determined by strong anion-exchange high-performance liquid chromatorgraphy.This method can be widely applied to the extraction and characterization of chondroitin sulfate from unknown raw materials,screening high-quality sources of functional polysaccharides,and laying a good foundation for thefollowing studyof the structure-function relationshipof polysaccharides.展开更多
基金supported by the National Key R&D Plan of China(Grant No.2018YFE0204204)the National Natural Science Foundation of China(Grant Nos.42050104,41790455,and 42072116).
文摘The climate paleogeography,especially the climate classifications,helps to interpret the global and regional climate changes and intuitively compare the climate conditions in different regions.However,the application of climate classification in deep time(i.e.,climate paleogeography)is prohibited due to the usually qualitatively constrained paleoclimate and the inconsistent descriptions and semantic heterogeneity of the climate types.In this study,a climate paleogeography knowledge graph is established under the framework of the Deep-Time Digital Earth program(DDE).The hierarchical knowledge graph consists of five paleoclimate classifications based on various strategies.The classifications are described and their strengths and weaknesses are fully evaluated in four aspects:“simplicity,applicability,quantifiability,and comparability”.We also reconstruct the global climate distributions in the Late Cretaceous according to these classifications.The results are compared and the relationships among these climate types in different classifications are evaluated.Our study unifies scientific concepts from different paleoclimate classifications,which provides an important theoretical basis for the application of paleoclimate classifications in deep time.
基金the National Key Research and Development Program of China(No.2018YFD0901101).
文摘This study was designed to establish a strategy for the extraction,purification,and structure analysis of chondroitin sulfate(cs)in milligram amounts.Crude acidic polysaccharides were extracted from six kinds of marine animals by enzymatic hydrolysis and hexadecylpyridinium chloride precipitation and purified by Q Sepharose Fast Flow strong anion exchange column.The purification of each crude polysaccharide was completed within 1 h.The structure of the polysaccharides,i.e.their chemical characterization,functional group,molecular weight and monosaccharide composition,were analyzed by colorimetry,nuclear magnetic resonace and high-performance liquid chromatogrpahy,respectively.All polysaccharides were identified as Cs.The oligosaccharide profile produced by enzyme hydrolysis of polysaccharides was determined by strong anion-exchange high-performance liquid chromatorgraphy.This method can be widely applied to the extraction and characterization of chondroitin sulfate from unknown raw materials,screening high-quality sources of functional polysaccharides,and laying a good foundation for thefollowing studyof the structure-function relationshipof polysaccharides.
