This study attempts to identify the dominant transport pathways,potential source areas,and their seasonal variation at sites with high inorganic nitrogen(IN)wet deposition flux in southern China.This is a long-term st...This study attempts to identify the dominant transport pathways,potential source areas,and their seasonal variation at sites with high inorganic nitrogen(IN)wet deposition flux in southern China.This is a long-term study(2010-2017)based on continuous deposition measurements at the Guangzhou urban site(GZ)and the Dinghushan Natural Reserve site(DHS)located in the Pearl River Delta(PRD)region.A dataset on monthly IN concentration in precipitation and wet deposition flux were provided.The average annual fluxes measured at both sites(GZ:33.04±9.52,DHS:20.52±10.22 kg N/(ha·year))were higher,while the ratios of reduced to oxidized N(GZ:1.19±0.77,DHS:1.25±0.84)were lower compared with the national mean level and the previous reported level throughout the PRD region.The dominant pathways were not always consistent with the highest proportional trajectory clusters.The transport pathways contributing most of deposition were identified in the north and northnortheast in the dry season and in the east-southeast,east,and south-southwest in the wet season.A weighted potential source contribution function(WPSCF)value>0.3 was determined reasonably to define the potential source area.Emission within the PRD region contributed the majority(≥95%at both sites)of the IN deposition in the wet season,while the contribution outside the region increased significantly in the dry season(GZ:27.86%,DHS:95.26%).Our results could help create more effective policy to control precursor emissions for IN fluxes,enabling reduction of the ecological risks due to excessive nitrogen.展开更多
Nonalcoholic fatty liver disease(NAFLD)is the most common chronic liver disease worldwide.Fat accumulation“sensitizes”the liver to insult and leads to nonalcoholic steatohepatitis(NASH).G protein-coupled receptor 35...Nonalcoholic fatty liver disease(NAFLD)is the most common chronic liver disease worldwide.Fat accumulation“sensitizes”the liver to insult and leads to nonalcoholic steatohepatitis(NASH).G protein-coupled receptor 35(GPR35)is involved in metabolic stresses,but its role in NAFLD is unknown.We report that hepatocyte GPR35 mitigates NASH by regulating hepatic cholesterol homeostasis.Specifically,we found that GPR35 overexpression in hepatocytes protected against high-fat/cholesterol/fructose(HFCF)diet-induced steatohepatitis,whereas loss of GPR35 had the opposite effect.Administration of the GPR35 agonist kynurenic acid(Kyna)suppressed HFCF diet-induced steatohepatitis in mice.Kyna/GPR35 induced expression of StAR-related lipid transfer protein 4(STARD4)through the ERK1/2 signaling pathway,ultimately resulting in hepatic cholesterol esterification and bile acid synthesis(BAS).The overexpression of STARD4 increased the expression of the BAS rate-limiting enzymes cytochrome P450 family 7 subfamily A member 1(CYP7A1)and CYP8B1,promoting the conversion of cholesterol to bile acid.The protective effect induced by GPR35 overexpression in hepatocytes disappeared in hepatocyte STARD4-knockdown mice.STARD4 overexpression in hepatocytes reversed the aggravation of HFCF diet-induced steatohepatitis caused by the loss of GPR35 expression in hepatocytes in mice.Our findings indicate that the GPR35–STARD4 axis is a promising therapeutic target for NAFLD.展开更多
In the last few decades,sulfonated carbon materials have garnered significant attention as Brøsted solid acid catalysts.The sulfonation process and catalytic activity of sulfonated biochar can be influenced by th...In the last few decades,sulfonated carbon materials have garnered significant attention as Brøsted solid acid catalysts.The sulfonation process and catalytic activity of sulfonated biochar can be influenced by the aromaticity and degree of condensation exhibited by biochar.However,the relationships between the aromaticity,sulfonating ability,and resultant catalytic activity are not fully understood.In this study,biochar samples pyrolyzed at 300-650℃ exhibiting different aromaticity and degrees of condensation were sulfonated and employed as sulfonate-bearing solid catalysts for hydrolytically removing tylosin.They exhibited excellent hydrolytic performance and their kinetic constants were positively correlated with the total acidity and negatively correlated with their aromaticity.This study has uncovered the relationship between the structure,properties,sulfonating ability,and subsequent hydrolytic performance of biochar samples.It was observed that the aromaticity of biochar decreased as the pyrolysis temperature increased.Lower pyrolysis temperatures resulted in a reduced degree of condensation,smaller ring size,and an increased number of ring edge sites available for sulfonation,ultimately leading to enhanced catalytic performance.These findings provide valuable insights into the fundamental chemistry behind sulfonation upgrading of biochar,with the aim of developing functional catalysts for mitigating antibiotics in contaminated water.展开更多
Carbon-based solid acids have been successfully employed as acidic catalysts for pollutant mitigation in wastewater.To fully tap the potentials of commercially viable carbons for the preparation of solid acids and enh...Carbon-based solid acids have been successfully employed as acidic catalysts for pollutant mitigation in wastewater.To fully tap the potentials of commercially viable carbons for the preparation of solid acids and enhance their catalytic performances is a challenging problem.In this work,three commercialized carbons including biochar,activated carbon and graphite were preprocessed(ball-milling,Hummer exfoliation,HNO3 soaking,and microwave heating in HNO_(3),etc.),sulfonated,and evaluated as solid-acid catalysts for tylosin mitigation.Graphite-originated solid acid performed the best through a balling-milling preprocess,while biochar-originated solid acids behaved well under all preprocessing treatments,in which 40 mg L^(−1) of tylosin was mitigated within 8 min by 1 g L^(−1) of biochar-originated solid acids.The biochar solid acid through the ball-milling preprocess presented high total acidity and large amounts of-SO_(3)H groups,due to dramatically increased surface area and the rise of activation groups(hydroxyl,alkyl and alkoxy groups,etc.)facilitating electrophilic reaction.In addition,decreased particle size and aromaticity and increased structural defects also contributed.Theoretical calculation of average local ionization energy(ALIE)of condensed aromatic model molecules with substituted activation groups confirmed the promoting effects on sulfonation from strong to weak were 8.40-9.06 eV.These findings have deepened the knowledge in tuning carbon surface chemistry for better sulfonation,thus strengthening catalytic degradation of tylosin.The value of this study is in pulling a clear thread for maneuvering solid-acid catalysts using carbons,which holds a novel promise for rationally functionalizing biochar-based catalysts for the remediation of macrolide antibiotics in polluted water.展开更多
基金supported by National Key Research and Development Plan(No.2017YFC0210100)the National Natural Science Foundation of China(Nos.41905086,41905107,42077205,41425020)+4 种基金the Special Fund Project for Science and Technology Innovation Strategy of Guangdong Province(No.2019B121205004)the Natural Science Foundation of Guangdong Province(No.2019A1515011291)the China Postdoctoral Science Foundation(No.2020M683174)the Air Quip(High resolution Air Quality Information for Policy)Project funded by the Research Council of Norway,the Collaborative Innovation Center of Climate Change,Jiangsu province,China,the high-performance computing platform of Jinan University,the Mt.Dinghu Forest Ecosystem Research Station,Chinese Academy of Sciences(CAS)the Comprehensive Observation and Study Site of Urban Meteorology and Environment,Sun Yat-sen University,and the Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies(No.2020B1212060025)
文摘This study attempts to identify the dominant transport pathways,potential source areas,and their seasonal variation at sites with high inorganic nitrogen(IN)wet deposition flux in southern China.This is a long-term study(2010-2017)based on continuous deposition measurements at the Guangzhou urban site(GZ)and the Dinghushan Natural Reserve site(DHS)located in the Pearl River Delta(PRD)region.A dataset on monthly IN concentration in precipitation and wet deposition flux were provided.The average annual fluxes measured at both sites(GZ:33.04±9.52,DHS:20.52±10.22 kg N/(ha·year))were higher,while the ratios of reduced to oxidized N(GZ:1.19±0.77,DHS:1.25±0.84)were lower compared with the national mean level and the previous reported level throughout the PRD region.The dominant pathways were not always consistent with the highest proportional trajectory clusters.The transport pathways contributing most of deposition were identified in the north and northnortheast in the dry season and in the east-southeast,east,and south-southwest in the wet season.A weighted potential source contribution function(WPSCF)value>0.3 was determined reasonably to define the potential source area.Emission within the PRD region contributed the majority(≥95%at both sites)of the IN deposition in the wet season,while the contribution outside the region increased significantly in the dry season(GZ:27.86%,DHS:95.26%).Our results could help create more effective policy to control precursor emissions for IN fluxes,enabling reduction of the ecological risks due to excessive nitrogen.
基金supported by the National Science Fund for Distinguished Young Scholars(#82225008,China)the National Natural Science Foundation of China(#82070608)+1 种基金the Anhui Provincial Natural Science Foundation(#2108085Y28,China)the Research Improvement Program of Anhui Medical University(#2019xkjT007,China).
文摘Nonalcoholic fatty liver disease(NAFLD)is the most common chronic liver disease worldwide.Fat accumulation“sensitizes”the liver to insult and leads to nonalcoholic steatohepatitis(NASH).G protein-coupled receptor 35(GPR35)is involved in metabolic stresses,but its role in NAFLD is unknown.We report that hepatocyte GPR35 mitigates NASH by regulating hepatic cholesterol homeostasis.Specifically,we found that GPR35 overexpression in hepatocytes protected against high-fat/cholesterol/fructose(HFCF)diet-induced steatohepatitis,whereas loss of GPR35 had the opposite effect.Administration of the GPR35 agonist kynurenic acid(Kyna)suppressed HFCF diet-induced steatohepatitis in mice.Kyna/GPR35 induced expression of StAR-related lipid transfer protein 4(STARD4)through the ERK1/2 signaling pathway,ultimately resulting in hepatic cholesterol esterification and bile acid synthesis(BAS).The overexpression of STARD4 increased the expression of the BAS rate-limiting enzymes cytochrome P450 family 7 subfamily A member 1(CYP7A1)and CYP8B1,promoting the conversion of cholesterol to bile acid.The protective effect induced by GPR35 overexpression in hepatocytes disappeared in hepatocyte STARD4-knockdown mice.STARD4 overexpression in hepatocytes reversed the aggravation of HFCF diet-induced steatohepatitis caused by the loss of GPR35 expression in hepatocytes in mice.Our findings indicate that the GPR35–STARD4 axis is a promising therapeutic target for NAFLD.
基金National Natural Science Foundation of China(51978052)State Key Joint Laboratory of Environmental Simulation and Pollution(19K01ESPCR).
文摘In the last few decades,sulfonated carbon materials have garnered significant attention as Brøsted solid acid catalysts.The sulfonation process and catalytic activity of sulfonated biochar can be influenced by the aromaticity and degree of condensation exhibited by biochar.However,the relationships between the aromaticity,sulfonating ability,and resultant catalytic activity are not fully understood.In this study,biochar samples pyrolyzed at 300-650℃ exhibiting different aromaticity and degrees of condensation were sulfonated and employed as sulfonate-bearing solid catalysts for hydrolytically removing tylosin.They exhibited excellent hydrolytic performance and their kinetic constants were positively correlated with the total acidity and negatively correlated with their aromaticity.This study has uncovered the relationship between the structure,properties,sulfonating ability,and subsequent hydrolytic performance of biochar samples.It was observed that the aromaticity of biochar decreased as the pyrolysis temperature increased.Lower pyrolysis temperatures resulted in a reduced degree of condensation,smaller ring size,and an increased number of ring edge sites available for sulfonation,ultimately leading to enhanced catalytic performance.These findings provide valuable insights into the fundamental chemistry behind sulfonation upgrading of biochar,with the aim of developing functional catalysts for mitigating antibiotics in contaminated water.
基金National Natural Science Foundation of China(51978052,42207456)State Key Joint Laboratory of Environmental Simulation and Pollution(19K01ESPCR).
文摘Carbon-based solid acids have been successfully employed as acidic catalysts for pollutant mitigation in wastewater.To fully tap the potentials of commercially viable carbons for the preparation of solid acids and enhance their catalytic performances is a challenging problem.In this work,three commercialized carbons including biochar,activated carbon and graphite were preprocessed(ball-milling,Hummer exfoliation,HNO3 soaking,and microwave heating in HNO_(3),etc.),sulfonated,and evaluated as solid-acid catalysts for tylosin mitigation.Graphite-originated solid acid performed the best through a balling-milling preprocess,while biochar-originated solid acids behaved well under all preprocessing treatments,in which 40 mg L^(−1) of tylosin was mitigated within 8 min by 1 g L^(−1) of biochar-originated solid acids.The biochar solid acid through the ball-milling preprocess presented high total acidity and large amounts of-SO_(3)H groups,due to dramatically increased surface area and the rise of activation groups(hydroxyl,alkyl and alkoxy groups,etc.)facilitating electrophilic reaction.In addition,decreased particle size and aromaticity and increased structural defects also contributed.Theoretical calculation of average local ionization energy(ALIE)of condensed aromatic model molecules with substituted activation groups confirmed the promoting effects on sulfonation from strong to weak were 8.40-9.06 eV.These findings have deepened the knowledge in tuning carbon surface chemistry for better sulfonation,thus strengthening catalytic degradation of tylosin.The value of this study is in pulling a clear thread for maneuvering solid-acid catalysts using carbons,which holds a novel promise for rationally functionalizing biochar-based catalysts for the remediation of macrolide antibiotics in polluted water.
