Biological carbon pumping(BCP)is a key process in which dissolved inorganic carbon in terrestrial aquatic ecosystems is utilized by aquatic autotrophs for photosynthesis and transformed into autochthonous organic matt...Biological carbon pumping(BCP)is a key process in which dissolved inorganic carbon in terrestrial aquatic ecosystems is utilized by aquatic autotrophs for photosynthesis and transformed into autochthonous organic matter(AOC).However,the mechanisms underlying BCP and the amount of generated AOC deposited effectively,are still poorly understood.Therefore,we conducted a systematic study combining modern hydrochemical monitoring and a sediment trap experiment in Fuxian Lake(Yunnan,SW China),the second-deepest plateau,oligotrophic freshwater lake in China.Temperature,pH,EC(electrical conductivity),DO(dissolved O2),[HCO3^-],[Ca^2+],SIc,partial CO2(pCO2)pressure,and carbon isotopic compositions of HCO3^-(δ^13CDIc)in water from Fuxian Lake all displayed distinct seasonal and vertical variations.This was especially apparent in an inverse correlation between pCO2 and DO,indicating that variations of hydrochemistry in the lake water were mainly controlled by the metabolism of the aquatic phototrophs.Furthermore,the lowest C/N ratios and highestδ^13Corg were recorded in the trap sediments.Analyses of the C/N ratio demonstrated that the proportions of AOC ranged from 30%to 100%of all OC,indicating that AOC was an important contributor to sedimentary organic matter(OC).It was calculated that the AOC flux in Fuxian Lake was 20.43 t C km^-2 in 2017.Therefore,AOC produced by carbonate weathering and aquatic photosynthesis could potentially be a significant carbon sink and may have an important contribution to solving the lack of carbon sinks in the global carbon cycle.展开更多
Salt severely restricts cotton(Gossypium hirsutum) growth and production.The present study was undertaken to study the effect of salt-induced hydrogen peroxide(H_2O_2) on antioxidant enzymes in cotton.Na Cl treatment ...Salt severely restricts cotton(Gossypium hirsutum) growth and production.The present study was undertaken to study the effect of salt-induced hydrogen peroxide(H_2O_2) on antioxidant enzymes in cotton.Na Cl treatment or exogenous H_2O_2 was used to investigate the relationship between H_2O_2 content and levels of antioxidant enzymes including superoxide dismutase(SOD),ascorbate peroxidase(APX),peroxidase(POD),and catalase(CAT),as well as the transcriptional levels of corresponding genes.H_2O_2 content increased within 24 h following 200 mmol L^(–1)Na Cl treatment.Both Na Cl-induced and exogenous H_2O_2 increased the activity of antioxidant enzymes including APX and SOD and upregulated the transcriptional levels of Ghc APX1,Gh Fe SOD,and Ghchl CSD.These increased activities and upregulated transcriptional levels were inhibited when the salt-induced H_2O_2 was scavenged by NAC.These results indicate that salt-induced H_2O_2 as a second signaling messenger modulates APX and SOD activities by regulating the transcription levels of corresponding genes,alleviating oxidative stress,and increasing salt tolerance in cotton.展开更多
The eutrophication of lakes is a global environmental problem.Regulating nitrogen(N)and phosphorus(P)on phytoplankton is considered to be the most important basis of lake eutrophication management.Therefore,the effect...The eutrophication of lakes is a global environmental problem.Regulating nitrogen(N)and phosphorus(P)on phytoplankton is considered to be the most important basis of lake eutrophication management.Therefore,the effects of dissolved inorganic carbon(DIC)on phytoplankton and its role in mitigating lake eutrophication have often been overlooked.In this study,the relationships between phytoplankton and DIC concentrations,carbon isotopic composition,nutrients(N and P),and hydrochemistry in the Erhai Lake(a karst lake)were investigated.The results showed that when the dissolved carbon dioxide(CO_(2)(aq))concentrations in the water were higher than 15μmol/L,the productivity of phytoplankton was controlled by the concentrations of TP and TN,especially by that of TP.When the N and P were sufficient and the CO_(2)(aq)concentrations were lower than 15μmol/L,the phytoplankton productivity was controlled by the concentrations of TP and DIC,especially by that of DIC.Additionally,DIC significantly affected the composition of the phytoplankton community in the lake(p<0.05).When the CO_(2)(aq)concentrations were higher than 15μmol/L,the relative abundance of Bacillariophyta and Chlorophyta was much higher than those of harmful Cyanophyta.Thus,high concentrations of CO_(2)(aq)can inhibit harmful Cyanophyta blooms.展开更多
Objective:The size and morphology of the right ventricular outflow tract(RVOT)in patients suffering from long-term pulmonary regurgitation(PR)after native RVOT(NRVOT)reconstruction are important factors affecting the ...Objective:The size and morphology of the right ventricular outflow tract(RVOT)in patients suffering from long-term pulmonary regurgitation(PR)after native RVOT(NRVOT)reconstruction are important factors affecting the feasibility,safety,and effectiveness of transcatheter pulmonary valve replacement.The purpose of this study was to evaluate the feasibility,safety,and effectiveness of a transthoracic Salus valve(Balance Medical Technology Co.,Ltd,Beijing,China)in patients with moderate-to-severe PR after NRVOT reconstruction.Methods:Patients with moderate-to-severe PR after NRVOT reconstruction were selected between June 2021 and November 2021 at Beijing Anzhen Hospital.Demographic data as well as preoperative,intraoperative,and follow-up data were reviewed.Results:Ten patients with moderate-to-severe PR after NRVOT reconstruction underwent physical examination,transthoracic echocardiography,and cardiovascular magnetic resonance imaging.Seven patients were selected for transthoracic Salus valve replacement.Six patients underwent implantation of the Salus valve successfully.One valve migrated and was embolized during recovery of the delivery device;the Salus valve was surgically explanted and sutured to the inner wall of the main pulmonary artery.At a mean follow-up of(5.5±1.1)months,dysfunction or migration of the Salus valve embolism was not observed.Conclusions:This early feasibility study demonstrates the feasibility,safety,and effectiveness of transthoracic implantation of a Salus valve in patients with moderate-to-severe PR after NRVOT reconstruction.The short-term effectiveness is clear,medium and long-term effectiveness requires longer follow-up.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 41430753, U1612441)
文摘Biological carbon pumping(BCP)is a key process in which dissolved inorganic carbon in terrestrial aquatic ecosystems is utilized by aquatic autotrophs for photosynthesis and transformed into autochthonous organic matter(AOC).However,the mechanisms underlying BCP and the amount of generated AOC deposited effectively,are still poorly understood.Therefore,we conducted a systematic study combining modern hydrochemical monitoring and a sediment trap experiment in Fuxian Lake(Yunnan,SW China),the second-deepest plateau,oligotrophic freshwater lake in China.Temperature,pH,EC(electrical conductivity),DO(dissolved O2),[HCO3^-],[Ca^2+],SIc,partial CO2(pCO2)pressure,and carbon isotopic compositions of HCO3^-(δ^13CDIc)in water from Fuxian Lake all displayed distinct seasonal and vertical variations.This was especially apparent in an inverse correlation between pCO2 and DO,indicating that variations of hydrochemistry in the lake water were mainly controlled by the metabolism of the aquatic phototrophs.Furthermore,the lowest C/N ratios and highestδ^13Corg were recorded in the trap sediments.Analyses of the C/N ratio demonstrated that the proportions of AOC ranged from 30%to 100%of all OC,indicating that AOC was an important contributor to sedimentary organic matter(OC).It was calculated that the AOC flux in Fuxian Lake was 20.43 t C km^-2 in 2017.Therefore,AOC produced by carbonate weathering and aquatic photosynthesis could potentially be a significant carbon sink and may have an important contribution to solving the lack of carbon sinks in the global carbon cycle.
基金financially supported by the Joint Funds of the National Natural Science Foundation of China and Xinjiang Province (No.U1303282)
文摘Salt severely restricts cotton(Gossypium hirsutum) growth and production.The present study was undertaken to study the effect of salt-induced hydrogen peroxide(H_2O_2) on antioxidant enzymes in cotton.Na Cl treatment or exogenous H_2O_2 was used to investigate the relationship between H_2O_2 content and levels of antioxidant enzymes including superoxide dismutase(SOD),ascorbate peroxidase(APX),peroxidase(POD),and catalase(CAT),as well as the transcriptional levels of corresponding genes.H_2O_2 content increased within 24 h following 200 mmol L^(–1)Na Cl treatment.Both Na Cl-induced and exogenous H_2O_2 increased the activity of antioxidant enzymes including APX and SOD and upregulated the transcriptional levels of Ghc APX1,Gh Fe SOD,and Ghchl CSD.These increased activities and upregulated transcriptional levels were inhibited when the salt-induced H_2O_2 was scavenged by NAC.These results indicate that salt-induced H_2O_2 as a second signaling messenger modulates APX and SOD activities by regulating the transcription levels of corresponding genes,alleviating oxidative stress,and increasing salt tolerance in cotton.
基金supported by the National Natural Science Foundation of China(Nos.42130501,42141008,and 41977298)the Strategic Priority Research Program of the Chinese Academy of Science(No.XDB40020000)Special thanks to the Dali Erhai Research Institute for supporting us in sampling Erhai Lake.
文摘The eutrophication of lakes is a global environmental problem.Regulating nitrogen(N)and phosphorus(P)on phytoplankton is considered to be the most important basis of lake eutrophication management.Therefore,the effects of dissolved inorganic carbon(DIC)on phytoplankton and its role in mitigating lake eutrophication have often been overlooked.In this study,the relationships between phytoplankton and DIC concentrations,carbon isotopic composition,nutrients(N and P),and hydrochemistry in the Erhai Lake(a karst lake)were investigated.The results showed that when the dissolved carbon dioxide(CO_(2)(aq))concentrations in the water were higher than 15μmol/L,the productivity of phytoplankton was controlled by the concentrations of TP and TN,especially by that of TP.When the N and P were sufficient and the CO_(2)(aq)concentrations were lower than 15μmol/L,the phytoplankton productivity was controlled by the concentrations of TP and DIC,especially by that of DIC.Additionally,DIC significantly affected the composition of the phytoplankton community in the lake(p<0.05).When the CO_(2)(aq)concentrations were higher than 15μmol/L,the relative abundance of Bacillariophyta and Chlorophyta was much higher than those of harmful Cyanophyta.Thus,high concentrations of CO_(2)(aq)can inhibit harmful Cyanophyta blooms.
基金supported by the National Key Research and Development Program of China(2020YFC1107903).
文摘Objective:The size and morphology of the right ventricular outflow tract(RVOT)in patients suffering from long-term pulmonary regurgitation(PR)after native RVOT(NRVOT)reconstruction are important factors affecting the feasibility,safety,and effectiveness of transcatheter pulmonary valve replacement.The purpose of this study was to evaluate the feasibility,safety,and effectiveness of a transthoracic Salus valve(Balance Medical Technology Co.,Ltd,Beijing,China)in patients with moderate-to-severe PR after NRVOT reconstruction.Methods:Patients with moderate-to-severe PR after NRVOT reconstruction were selected between June 2021 and November 2021 at Beijing Anzhen Hospital.Demographic data as well as preoperative,intraoperative,and follow-up data were reviewed.Results:Ten patients with moderate-to-severe PR after NRVOT reconstruction underwent physical examination,transthoracic echocardiography,and cardiovascular magnetic resonance imaging.Seven patients were selected for transthoracic Salus valve replacement.Six patients underwent implantation of the Salus valve successfully.One valve migrated and was embolized during recovery of the delivery device;the Salus valve was surgically explanted and sutured to the inner wall of the main pulmonary artery.At a mean follow-up of(5.5±1.1)months,dysfunction or migration of the Salus valve embolism was not observed.Conclusions:This early feasibility study demonstrates the feasibility,safety,and effectiveness of transthoracic implantation of a Salus valve in patients with moderate-to-severe PR after NRVOT reconstruction.The short-term effectiveness is clear,medium and long-term effectiveness requires longer follow-up.
