The West Pacific Ocean is considered as the provenance center of global marine life and has the highest species diversity of numerous marine taxa.The phytoplankton,as the primary producer at the base of the food chain...The West Pacific Ocean is considered as the provenance center of global marine life and has the highest species diversity of numerous marine taxa.The phytoplankton,as the primary producer at the base of the food chain,effects on climate change,fish resources as well as the entire ecosystem.However,there are few large-scale surveys covering several currents with different hydrographic characteristics.This study aimed to explore the relationships between the spatio-temporal variation in phytoplankton community structure and different water masses.A total of 630 water samples and 90 net samples of phytoplankton were collected at 45 stations in the Northwest Pacific Ocean(21.0°–42.0°N,118.0°–156.0°E)during spring and summer 2017.A total of 281 phytoplankton taxa(>5μm)belonging to 61 genera were identified in the study area.The distribution pattern of the phytoplankton community differed significantly both spatially and temporally.The average abundances of phytoplankton in spring and summer were 797.07×10~2 cells/L and 84.94×10~2 cells/L,respectively.Whether in spring or summer,the maximum abundance always appeared in the northern transition region affected by the Oyashio Current,where nutrients were abundant and diatoms dominated the phytoplankton community;whereas the phytoplankton abundance was very low in the oligotrophic Kuroshio region,and the proportion of dinoflagellates in total abundance increased significantly.The horizontal distribution of phytoplankton abundance increased from low to high latitudes,which was consistent with the trend of nutrient distributions,but contrary to that of water temperature and salinity.In the northern area affected by the Oyashio Current,the phytoplankton abundance was mainly concentrated in the upper 30 m of water column,while the maximum abundance often occurred at depths of 50–75 m in the south-central area affected by the Kuroshio Current.Pearson correlation and redundancy analysis(RDA)showed that phytoplankton abundance was significant negatively correlated wi展开更多
Theπ-πstacking is a well-recognized intermolecular interaction that is responsible for the construction of electron hopping channels in numerous conducting frameworks/aggregates.However,the exact role ofπ-to-πchan...Theπ-πstacking is a well-recognized intermolecular interaction that is responsible for the construction of electron hopping channels in numerous conducting frameworks/aggregates.However,the exact role ofπ-to-πchannels within typical single crystalline organic semiconductors remains unclear as the orientations of these molecules are diverse,and their control usually requires additional side chain groups that misrepresent the intrinsic properties of the original semiconducting molecules.Therefore,the construction of conduction channels with intrinsicπ-πstacking in the molecule-based device is crucial for the utilization of their unique transport characteristics and understanding of the transport mechanism.To this end,we present a molecular intercalation strategy that integrates two-dimensional layered materials with functional organic semiconductor molecules for functional molecule-based electronics.Various organic semiconductor molecules can be effectively intercalated into the van der Waals gaps of semi-metallic TaS_(2) withπ-πstacking configuration and controlled intercalant content.Our results show that the vertical charge transport in the stacking direction shows a tunneling-dominated mechanism that strongly depends on the molecular structures.Furthermore,we demonstrated a new type of molecule-based vertical transistor in which TaS_(2) andπ-πstacked organic molecules function as the electrical contact and the active channel,respectively.On/off ratios as high as 447 are achieved under electrostatic modulation in ionic liquid,comparable to the current state-of-the-art molecular transistors.Our study provides an ideal platform for probing intrinsic charge transport acrossπ-πstacked conjugated molecules and also a feasible approach for the construction of high-performance molecule-based electronic devices.展开更多
The central and western Tibetan Plateau(CWTP)is characterized by harsh environment and strong interactions among the spheres of earth as well as significant changes in climate and water cycles over the past four decad...The central and western Tibetan Plateau(CWTP)is characterized by harsh environment and strong interactions among the spheres of earth as well as significant changes in climate and water cycles over the past four decades.The lack of precipitation observations is a bottleneck for the study of land surface processes in this region.Over the past six years,we have designed and established two observation transects across the south-north and the west-east in this region to obtain hourly rainfall data during the warm season(May-September).The south-north transect extends from Yadong Valley on the southern slope of the Himalayas to Shuanghu County in the hinterland of the plateau,with a total of 31stations;the west-east transect extends from Shiquanhe in the west to Naqu in the central TP,with a total of 22 stations.The observation dataset has been applied to clarify the spatiotemporal characteristics of precipitation in the CWTP,to evaluate the quality of typical gridded precipitation products,to support the development of regional climate models,and to reveal the processes of summertime lake-air interactions.The observation dataset has been released in the National Tibetan Plateau Data Center.展开更多
The coastal ecosystems are highly sensitive to climate change and are usually influenced by variations in phytoplankton communities and water physiochemical factors.In the present study,the phytoplankton community,chl...The coastal ecosystems are highly sensitive to climate change and are usually influenced by variations in phytoplankton communities and water physiochemical factors.In the present study,the phytoplankton community,chlorophyll a(Chl a)and their relationships with environmental variables and dimethylsulfide(DMS)and dimethylsulfoniopropionate(DMSP)were investigated in spring 2017(March 24 to April 16)in the East China Sea(26.0°-33.0°N,120.0°-128.0°E)and southern Yellow Sea(31.0°-36.0°N,120.0°-125.0°E).The spatial distributions of phytoplankton species composition and cell density were investigated by qualitative and quantitative methods and were compared with historical data to study phytoplankton species succession in the survey area.The results showed that there were 275 phytoplankton species belonging to 90 genera and 6 phyla in the survey area,of which 208 species belonged to 62 genera of Bacillariophyta and 56 species belonged to 20 genera of Pyrrophyta.The dominant phytoplankton species were Skeletonema dohrnii,Chaetoceros vanheurckii and Prorocentrum donghaiense.The phytoplankton cell densities ranged from 0.06×10^(4)cells/L to 418.73×10^(4)cells/L,with an average value of 21.46×10^(4)cells/L.In spring,the average ratio of Bacillariophyta/Pyrrophyta was41.13 for the entire study area.The areas with high phytoplankton cell density were mainly distributed in the northern South Yellow Sea and offshore waters of the East China Sea.According to a canonical correspondence analysis among phytoplankton and environmental parameters,the water Chl a concentrations were notably consistent with phytoplankton cell density(P<0.001),and both showed significant negative correlations with salinity and nitrite(P<0.05)and significant positive correlations with dissolved oxygen and pH(P<0.001).There was a significant positive correlation between diatom(both in cell density and in dominant species)and DMS(P<0.05),which indicated that diatoms play a greater role in DMS production in this investigated area.展开更多
Global warming has caused Arctic sea ice to rapidly retreat,which is affecting phytoplankton,the primary producers at the base of the food chain,as well as the entire ecosystem.However,few studies with large spatial s...Global warming has caused Arctic sea ice to rapidly retreat,which is affecting phytoplankton,the primary producers at the base of the food chain,as well as the entire ecosystem.However,few studies with large spatial scales related to the Arctic Basin at high latitude have been conducted.This study aimed to investigate the relationship between changes in phytoplankton community structure and ice conditions.Fifty surface and 41 vertically stratified water samples from the western Arctic Ocean（67.0°–88°26′N,152°–178°54′W） were collected by the Chinese icebreaker R/V Xuelong from July 20 to August 30,2010 during China＇s fourth Arctic expedition.Using these samples,the species composition,spatial distribution,and regional disparities of phytoplankton during different stages of ice melt were assessed.A total of 157 phytoplankton taxa（〉5 μm） belonging to 69 genera were identified in the study area.The most abundant species were Navicula pelagica and Thalassiosira nordenskioeldii,accounting for 31.23% and 14.12% of the total phytoplankton abundance,respectively.The average abundance during the departure trip and the return trip were 797.07×10~2 cells/L and 84.94×10~2 cells/L,respectively.The highest abundance was observed at Sta.R09 in the north of Herald Shoal,where Navicula pelagica was the dominant species accounting for 59.42% of the abundance.The vertical distribution of phytoplankton abundance displayed regional differences,and the maximum abundances were confined to the lower layers of the euphotic zone near the layers of the halocline,thermocline,and nutricline.The species abundance of phytoplankton decreased from the low-latitude shelf to the high-latitude basin on both the departure and return trips.The phytoplankton community structure in the shallow continental shelf changed markedly during different stages of ice melt,and there was shift in dominant species from centric to pennate diatoms.Results of canonical correspondence analysis（CCA） showed that there were two distinct comm展开更多
目的观察针刺配合中药及人工泪液治疗肝肾阴亏型泪液缺乏性干眼症的临床疗效。方法将80例肝肾阴亏型泪液缺乏性干眼症患者随机分为A组30例、B组25例和C组25例。A组采用针刺配合中药及人工泪液治疗,B组采用中药配合人工泪液治疗,C组采用...目的观察针刺配合中药及人工泪液治疗肝肾阴亏型泪液缺乏性干眼症的临床疗效。方法将80例肝肾阴亏型泪液缺乏性干眼症患者随机分为A组30例、B组25例和C组25例。A组采用针刺配合中药及人工泪液治疗,B组采用中药配合人工泪液治疗,C组采用单纯人工泪液治疗。观察各组治疗前后视力、泪液分泌试验(Schirmer I test, SIT)、泪膜破裂时间(break-up time, BUT)、角膜荧光染色(fluorescein staining, FL)、眼部症状评分及中医证候评分的变化情况,并比较各组临床疗效。结果 A组治疗后双眼视力与同组治疗前比较,差异均具有统计学意义(P<0.01);B组治疗后左眼视力与同组治疗前比较,差异具有统计学意义(P<0.05)。各组治疗后双眼SIT、BUT、FL评分与同组治疗前比较,差异均具有统计学意义(P<0.01)。A组治疗后双眼视力评分、SIT与B组和C组比较,差异均具有统计学意义(P<0.01,P<0.05)。A组和B组治疗后双眼BUT、FL评分与C组比较,差异均具有统计学意义(P<0.05,P<0.01)。B组治疗后右眼FL评分与C组比较,差异具有统计学意义(P<0.05)。A组和B组治疗后各项眼部症状(干涩感、异物感、疲劳感)评分与同组治疗前比较,差异均有统计学意义(P<0.01);C组治疗后干涩感、疲劳感评分与同组治疗前比较,差异均有统计学意义(P<0.01,P<0.05)。A组治疗后各项眼部症状评分与C组比较,差异均具有统计学意义(P<0.01);B组治疗后干涩感评分与C组比较,差异具有统计学意义(P<0.05)。A组总有效率为93.3%,B组为80.0%,C组为40.0%;A组中医证候总有效率为90.0%,B组为80.0%,C组为8.0%。A组和B组总有效率及中医证候总有效率与C组比较,差异均具有统计学意义(P<0.01)。结论针刺配合中药及人工泪液是一种治疗肝肾阴亏型泪液缺乏性干眼症的有效方法,可缓解患者症状,提高视力。展开更多
基金The Public Science and Technology Research Funds Projects of Ocean under contract No.201305027the project sponsored by the Scientific Research Foundation of Third Institute of Oceanography,SOA under contract No.2017009。
文摘The West Pacific Ocean is considered as the provenance center of global marine life and has the highest species diversity of numerous marine taxa.The phytoplankton,as the primary producer at the base of the food chain,effects on climate change,fish resources as well as the entire ecosystem.However,there are few large-scale surveys covering several currents with different hydrographic characteristics.This study aimed to explore the relationships between the spatio-temporal variation in phytoplankton community structure and different water masses.A total of 630 water samples and 90 net samples of phytoplankton were collected at 45 stations in the Northwest Pacific Ocean(21.0°–42.0°N,118.0°–156.0°E)during spring and summer 2017.A total of 281 phytoplankton taxa(>5μm)belonging to 61 genera were identified in the study area.The distribution pattern of the phytoplankton community differed significantly both spatially and temporally.The average abundances of phytoplankton in spring and summer were 797.07×10~2 cells/L and 84.94×10~2 cells/L,respectively.Whether in spring or summer,the maximum abundance always appeared in the northern transition region affected by the Oyashio Current,where nutrients were abundant and diatoms dominated the phytoplankton community;whereas the phytoplankton abundance was very low in the oligotrophic Kuroshio region,and the proportion of dinoflagellates in total abundance increased significantly.The horizontal distribution of phytoplankton abundance increased from low to high latitudes,which was consistent with the trend of nutrient distributions,but contrary to that of water temperature and salinity.In the northern area affected by the Oyashio Current,the phytoplankton abundance was mainly concentrated in the upper 30 m of water column,while the maximum abundance often occurred at depths of 50–75 m in the south-central area affected by the Kuroshio Current.Pearson correlation and redundancy analysis(RDA)showed that phytoplankton abundance was significant negatively correlated wi
基金support by the National Natural Science Foundation of China(Nos.22172075,92156024)the Fundamental Research Funds for the Central Universities in China(Nos.0210/14380174,14380273)+4 种基金Beijing National Laboratory for Molecular Sciences(No.BNLMS202107)Thousand Talents Plan of Jiangxi Province(No.jxsq2019102002)support by the National Natural Science Foundation of China(No.22033004)support from Early Career Scheme Project(No.21302821)General Research Fund Project(No.11314322)from the University Grants Committee of Hong Kong.
文摘Theπ-πstacking is a well-recognized intermolecular interaction that is responsible for the construction of electron hopping channels in numerous conducting frameworks/aggregates.However,the exact role ofπ-to-πchannels within typical single crystalline organic semiconductors remains unclear as the orientations of these molecules are diverse,and their control usually requires additional side chain groups that misrepresent the intrinsic properties of the original semiconducting molecules.Therefore,the construction of conduction channels with intrinsicπ-πstacking in the molecule-based device is crucial for the utilization of their unique transport characteristics and understanding of the transport mechanism.To this end,we present a molecular intercalation strategy that integrates two-dimensional layered materials with functional organic semiconductor molecules for functional molecule-based electronics.Various organic semiconductor molecules can be effectively intercalated into the van der Waals gaps of semi-metallic TaS_(2) withπ-πstacking configuration and controlled intercalant content.Our results show that the vertical charge transport in the stacking direction shows a tunneling-dominated mechanism that strongly depends on the molecular structures.Furthermore,we demonstrated a new type of molecule-based vertical transistor in which TaS_(2) andπ-πstacked organic molecules function as the electrical contact and the active channel,respectively.On/off ratios as high as 447 are achieved under electrostatic modulation in ionic liquid,comparable to the current state-of-the-art molecular transistors.Our study provides an ideal platform for probing intrinsic charge transport acrossπ-πstacked conjugated molecules and also a feasible approach for the construction of high-performance molecule-based electronic devices.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(Grants No.2019QZKK0206)the National Key Research and Development Project(Grants No.2018YFA0605400)the National Natural Science Foundation of China(Grants No.41975125)。
文摘The central and western Tibetan Plateau(CWTP)is characterized by harsh environment and strong interactions among the spheres of earth as well as significant changes in climate and water cycles over the past four decades.The lack of precipitation observations is a bottleneck for the study of land surface processes in this region.Over the past six years,we have designed and established two observation transects across the south-north and the west-east in this region to obtain hourly rainfall data during the warm season(May-September).The south-north transect extends from Yadong Valley on the southern slope of the Himalayas to Shuanghu County in the hinterland of the plateau,with a total of 31stations;the west-east transect extends from Shiquanhe in the west to Naqu in the central TP,with a total of 22 stations.The observation dataset has been applied to clarify the spatiotemporal characteristics of precipitation in the CWTP,to evaluate the quality of typical gridded precipitation products,to support the development of regional climate models,and to reveal the processes of summertime lake-air interactions.The observation dataset has been released in the National Tibetan Plateau Data Center.
基金The National Key Research and Development Program of China under contract Nos 2016YFA0601302 and 2018FY100202。
文摘The coastal ecosystems are highly sensitive to climate change and are usually influenced by variations in phytoplankton communities and water physiochemical factors.In the present study,the phytoplankton community,chlorophyll a(Chl a)and their relationships with environmental variables and dimethylsulfide(DMS)and dimethylsulfoniopropionate(DMSP)were investigated in spring 2017(March 24 to April 16)in the East China Sea(26.0°-33.0°N,120.0°-128.0°E)and southern Yellow Sea(31.0°-36.0°N,120.0°-125.0°E).The spatial distributions of phytoplankton species composition and cell density were investigated by qualitative and quantitative methods and were compared with historical data to study phytoplankton species succession in the survey area.The results showed that there were 275 phytoplankton species belonging to 90 genera and 6 phyla in the survey area,of which 208 species belonged to 62 genera of Bacillariophyta and 56 species belonged to 20 genera of Pyrrophyta.The dominant phytoplankton species were Skeletonema dohrnii,Chaetoceros vanheurckii and Prorocentrum donghaiense.The phytoplankton cell densities ranged from 0.06×10^(4)cells/L to 418.73×10^(4)cells/L,with an average value of 21.46×10^(4)cells/L.In spring,the average ratio of Bacillariophyta/Pyrrophyta was41.13 for the entire study area.The areas with high phytoplankton cell density were mainly distributed in the northern South Yellow Sea and offshore waters of the East China Sea.According to a canonical correspondence analysis among phytoplankton and environmental parameters,the water Chl a concentrations were notably consistent with phytoplankton cell density(P<0.001),and both showed significant negative correlations with salinity and nitrite(P<0.05)and significant positive correlations with dissolved oxygen and pH(P<0.001).There was a significant positive correlation between diatom(both in cell density and in dominant species)and DMS(P<0.05),which indicated that diatoms play a greater role in DMS production in this investigated area.
基金The Public Science and Technology Research Funds Projects of Ocean under contract No.201305027the National Natural Science Foundation of China under contract No.41306204
文摘Global warming has caused Arctic sea ice to rapidly retreat,which is affecting phytoplankton,the primary producers at the base of the food chain,as well as the entire ecosystem.However,few studies with large spatial scales related to the Arctic Basin at high latitude have been conducted.This study aimed to investigate the relationship between changes in phytoplankton community structure and ice conditions.Fifty surface and 41 vertically stratified water samples from the western Arctic Ocean（67.0°–88°26′N,152°–178°54′W） were collected by the Chinese icebreaker R/V Xuelong from July 20 to August 30,2010 during China＇s fourth Arctic expedition.Using these samples,the species composition,spatial distribution,and regional disparities of phytoplankton during different stages of ice melt were assessed.A total of 157 phytoplankton taxa（〉5 μm） belonging to 69 genera were identified in the study area.The most abundant species were Navicula pelagica and Thalassiosira nordenskioeldii,accounting for 31.23% and 14.12% of the total phytoplankton abundance,respectively.The average abundance during the departure trip and the return trip were 797.07×10~2 cells/L and 84.94×10~2 cells/L,respectively.The highest abundance was observed at Sta.R09 in the north of Herald Shoal,where Navicula pelagica was the dominant species accounting for 59.42% of the abundance.The vertical distribution of phytoplankton abundance displayed regional differences,and the maximum abundances were confined to the lower layers of the euphotic zone near the layers of the halocline,thermocline,and nutricline.The species abundance of phytoplankton decreased from the low-latitude shelf to the high-latitude basin on both the departure and return trips.The phytoplankton community structure in the shallow continental shelf changed markedly during different stages of ice melt,and there was shift in dominant species from centric to pennate diatoms.Results of canonical correspondence analysis（CCA） showed that there were two distinct comm
文摘目的观察针刺配合中药及人工泪液治疗肝肾阴亏型泪液缺乏性干眼症的临床疗效。方法将80例肝肾阴亏型泪液缺乏性干眼症患者随机分为A组30例、B组25例和C组25例。A组采用针刺配合中药及人工泪液治疗,B组采用中药配合人工泪液治疗,C组采用单纯人工泪液治疗。观察各组治疗前后视力、泪液分泌试验(Schirmer I test, SIT)、泪膜破裂时间(break-up time, BUT)、角膜荧光染色(fluorescein staining, FL)、眼部症状评分及中医证候评分的变化情况,并比较各组临床疗效。结果 A组治疗后双眼视力与同组治疗前比较,差异均具有统计学意义(P<0.01);B组治疗后左眼视力与同组治疗前比较,差异具有统计学意义(P<0.05)。各组治疗后双眼SIT、BUT、FL评分与同组治疗前比较,差异均具有统计学意义(P<0.01)。A组治疗后双眼视力评分、SIT与B组和C组比较,差异均具有统计学意义(P<0.01,P<0.05)。A组和B组治疗后双眼BUT、FL评分与C组比较,差异均具有统计学意义(P<0.05,P<0.01)。B组治疗后右眼FL评分与C组比较,差异具有统计学意义(P<0.05)。A组和B组治疗后各项眼部症状(干涩感、异物感、疲劳感)评分与同组治疗前比较,差异均有统计学意义(P<0.01);C组治疗后干涩感、疲劳感评分与同组治疗前比较,差异均有统计学意义(P<0.01,P<0.05)。A组治疗后各项眼部症状评分与C组比较,差异均具有统计学意义(P<0.01);B组治疗后干涩感评分与C组比较,差异具有统计学意义(P<0.05)。A组总有效率为93.3%,B组为80.0%,C组为40.0%;A组中医证候总有效率为90.0%,B组为80.0%,C组为8.0%。A组和B组总有效率及中医证候总有效率与C组比较,差异均具有统计学意义(P<0.01)。结论针刺配合中药及人工泪液是一种治疗肝肾阴亏型泪液缺乏性干眼症的有效方法,可缓解患者症状,提高视力。
