Fluorescent carbon dots(CDs)have been identified as potential nanosensors and attracted tremendous research interests in wide areas including anti-counterfeiting,environmental and biological sensing and imaging in con...Fluorescent carbon dots(CDs)have been identified as potential nanosensors and attracted tremendous research interests in wide areas including anti-counterfeiting,environmental and biological sensing and imaging in considering of the attractive optical properties.In this work,we present a CDs based fluorescent sensor from polyvinylpyrrolidone,citric acid,and methionine as precursors by hydrothermal approach.The selective quantifying of Fe^(3+)and ascorbic acid(AA)are based on the fluorescent on-off-on process,in which the fluorescent quenching is induced by the coordination of the Fe^(3+)on the surface of the CDs,while the fluorescence recovery is mainly attributed to redox reaction between Fe^(3+)and AA,breaking the coordination and bringing the fluorescence back.Inspired by the good water solubility and biocompatibility,significant photostability,superior photobleaching resistance as well as high selectivity,sensitivity,and interference immunity,which are constructed mainly from the N,S-doping and methionine surface functionalization,the CDs have not only been employed as fluorescence ink in multiple anticounterfeiting printing and confidential document writing or transmitting,but also been developed as promising fluorescence sensors in solution and solid by CDs doped test strips and hydrogels for effectively monitoring and removing of Fe^(3+)and AA in environmental aqueous solution.The CDs have been also implemented as effective diagnostic candidates for imaging and tracking of Fe^(3+)and AA in living cells,accelerating the understanding of their function and importance in related biological processes for the prevention and treatment specific diseases.展开更多
CONSPECTUS:The carbon balance has been disrupted by the widespread use of fossil fuels and subsequent excessive emissions of carbon dioxide(CO_(2)),which has become an increasingly critical environmental challenge for...CONSPECTUS:The carbon balance has been disrupted by the widespread use of fossil fuels and subsequent excessive emissions of carbon dioxide(CO_(2)),which has become an increasingly critical environmental challenge for human society.The production and use of renewable energy sources and/or chemicals have been proposed as important strategies to reduce emissions,of which the electrochemical CO_(2)(or CO)reduction reaction(CO_(2)RR/CORR)in the aqueous systems represents a promising approach.Benefitted by the capacity of manufacturing high-value-added products(e.g.,ethylene,ethanol,formic acid,etc.)with a net-zero carbon emission,copper-based CO_(2)RR/CORR powered by sustainable electricity is regarded as a potential candidate for carbon neutrality.However,the diversity of selectivities in copper-based systems poses a great challenge to the research in this field and sets a great obstacle for future industrialization.To date,scientists have revealed that the electrocatalyst design and preparation play a significant role in achieving efficient and selective CO_(2)-to-chemical(or CO-to-chemical)conversion.Although substantial efforts have been dedicated to the catalyst preparation and corresponding electrosynthesis of sustainable chemicals from CO_(2)/CO so far,most of them are still derived from empirical or random searches,which are relatively inefficient and cost-intensive.Most of the mechanism studies have suggested that both intrinsic properties(such as electron states)and extrinsic environmental factors(such as surface energy)of a catalyst can significantly alter catalytic performance.Thus,these two topics are mainly discussed for copper-based catalyst developments in this Account.Here,we provided a concise and comprehensive introduction to the well-established strategies employed for the design of copperbased electrocatalysts for CO_(2)RR/CORR.We used several examples from our research group,as well as representative studies of other research groups in this field during the recent five years,with the perspectives of tuning local electron states,regulating alloy phases,modifying interfacial coverages,and adjusting other interfacial microenvironments(e.g.,molecule modification or surface energy).Finally,we employed the techno-economic assessment with a viewpoint on the future application of CO_(2)/CO electroreduction in manufacturing sustainable chemicals.Our study indicates that when carbon price is taken into account,the electrocatalytic CO_(2)-to-chemical conversion can be more market-competitive,and several potential value-added products including formate,methanol,ethylene,and ethanol can all make profits under optimal operating conditions.Moreover,a downstream module employing traditional chemical industrial processes(e.g.,thermal polymerization,catalytic hydrolysis,or condensation process)will also make the whole electrolysis system profitable in the future.These design principles,combined with the recent advances in the development of efficient copper-based electrocatalysts,may provide a low-cost and long-lasting catalytic system for a profitable industrial-scale CO_(2)RR in the future.展开更多
Coronavirus disease 2019(COVID-19),caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),has spread rapidly around the world,posing a major threat to human health and the economy.Currently,long-term da...Coronavirus disease 2019(COVID-19),caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),has spread rapidly around the world,posing a major threat to human health and the economy.Currently,long-term data on viral shedding and the serum antibody responses in COVID-19 patients are still limited.Herein,we report the clinical features,viral RNA loads,and serum antibody levels in a cohort of 112 COVID-19 patients admitted to the Honghu People’s Hospital,Hubei Province,China.Overall,5.36%(6/112)of patients showed persistent viral RNA shedding(>45 days).The peak viral load was higher in the severe disease group than in the mild group(median cycle threshold value,36.4 versus 31.5;P=0.002).For most patients the disappearance of IgM antibodies occurred approximately 4–6 weeks after symptoms onset,while IgG persisted for over 194 days after the onset of symptoms,although patients showed a 46%reduction in antibodies titres against SARS-CoV-2 nucleocapsid protein compared with the acute phase.We also studied18 asymptomatic individuals with RT-qPCR confirmed SARS-CoV-2 infection together with 17 symptomatic patients,and the asymptomatic individuals were the close contacts of these symptomatic cases.Delayed IgG seroconversion and lower IgM seropositive rates were observed in asymptomatic individuals.These data indicate that higher viral loads and stronger antibody responses are related to more severe disease status in patients with SARS-CoV-2 infection,and the antibodies persisted in the recovered patient for more than 6 months so that the vaccine may provide protection against SARS-CoV-2 infection.展开更多
The electrochemical reduction of carbon dioxide(CO_(2))to value-added fuels and chemicals provides a promising way to realize sustainable carbon recycling[1].Developing robust electrocatalysts with high activity and s...The electrochemical reduction of carbon dioxide(CO_(2))to value-added fuels and chemicals provides a promising way to realize sustainable carbon recycling[1].Developing robust electrocatalysts with high activity and selectivity is critically important for efficient electrochemical CO_(2)reduction reaction(CO_(2)RR).Generally,it is challenging to achieve high efficiency and selectivity simultaneously in the CO_(2)RR due to the multi-proton/electron transfer processes and complex reaction intermediates.展开更多
基金supported by the National Natural Science Foundation of China(Nos.22171223,22179107,22077099,and 21807087)the Technology Innovation Leading Program of Shaanxi(No.2020TG−031)+2 种基金the Shaanxi Provincial Natural Science Fund Project(No.2018JQ2061)the Xi’an City Science and Technology Project(Nos.2020KJRC011 and 2019218214GXRC018CG019−GXYD18.4)the Outstanding Youth Science Fund of Xi’an University of Science and Technology(No.2018YQ3-14).
文摘Fluorescent carbon dots(CDs)have been identified as potential nanosensors and attracted tremendous research interests in wide areas including anti-counterfeiting,environmental and biological sensing and imaging in considering of the attractive optical properties.In this work,we present a CDs based fluorescent sensor from polyvinylpyrrolidone,citric acid,and methionine as precursors by hydrothermal approach.The selective quantifying of Fe^(3+)and ascorbic acid(AA)are based on the fluorescent on-off-on process,in which the fluorescent quenching is induced by the coordination of the Fe^(3+)on the surface of the CDs,while the fluorescence recovery is mainly attributed to redox reaction between Fe^(3+)and AA,breaking the coordination and bringing the fluorescence back.Inspired by the good water solubility and biocompatibility,significant photostability,superior photobleaching resistance as well as high selectivity,sensitivity,and interference immunity,which are constructed mainly from the N,S-doping and methionine surface functionalization,the CDs have not only been employed as fluorescence ink in multiple anticounterfeiting printing and confidential document writing or transmitting,but also been developed as promising fluorescence sensors in solution and solid by CDs doped test strips and hydrogels for effectively monitoring and removing of Fe^(3+)and AA in environmental aqueous solution.The CDs have been also implemented as effective diagnostic candidates for imaging and tracking of Fe^(3+)and AA in living cells,accelerating the understanding of their function and importance in related biological processes for the prevention and treatment specific diseases.
文摘CONSPECTUS:The carbon balance has been disrupted by the widespread use of fossil fuels and subsequent excessive emissions of carbon dioxide(CO_(2)),which has become an increasingly critical environmental challenge for human society.The production and use of renewable energy sources and/or chemicals have been proposed as important strategies to reduce emissions,of which the electrochemical CO_(2)(or CO)reduction reaction(CO_(2)RR/CORR)in the aqueous systems represents a promising approach.Benefitted by the capacity of manufacturing high-value-added products(e.g.,ethylene,ethanol,formic acid,etc.)with a net-zero carbon emission,copper-based CO_(2)RR/CORR powered by sustainable electricity is regarded as a potential candidate for carbon neutrality.However,the diversity of selectivities in copper-based systems poses a great challenge to the research in this field and sets a great obstacle for future industrialization.To date,scientists have revealed that the electrocatalyst design and preparation play a significant role in achieving efficient and selective CO_(2)-to-chemical(or CO-to-chemical)conversion.Although substantial efforts have been dedicated to the catalyst preparation and corresponding electrosynthesis of sustainable chemicals from CO_(2)/CO so far,most of them are still derived from empirical or random searches,which are relatively inefficient and cost-intensive.Most of the mechanism studies have suggested that both intrinsic properties(such as electron states)and extrinsic environmental factors(such as surface energy)of a catalyst can significantly alter catalytic performance.Thus,these two topics are mainly discussed for copper-based catalyst developments in this Account.Here,we provided a concise and comprehensive introduction to the well-established strategies employed for the design of copperbased electrocatalysts for CO_(2)RR/CORR.We used several examples from our research group,as well as representative studies of other research groups in this field during the recent five years,with the perspectives of tuning local electron states,regulating alloy phases,modifying interfacial coverages,and adjusting other interfacial microenvironments(e.g.,molecule modification or surface energy).Finally,we employed the techno-economic assessment with a viewpoint on the future application of CO_(2)/CO electroreduction in manufacturing sustainable chemicals.Our study indicates that when carbon price is taken into account,the electrocatalytic CO_(2)-to-chemical conversion can be more market-competitive,and several potential value-added products including formate,methanol,ethylene,and ethanol can all make profits under optimal operating conditions.Moreover,a downstream module employing traditional chemical industrial processes(e.g.,thermal polymerization,catalytic hydrolysis,or condensation process)will also make the whole electrolysis system profitable in the future.These design principles,combined with the recent advances in the development of efficient copper-based electrocatalysts,may provide a low-cost and long-lasting catalytic system for a profitable industrial-scale CO_(2)RR in the future.
基金supported by grants from the National Science and Technology Major Project of China(2018ZX10301202-003)the Collaboration and Innovation Health Care Major Project of Guangzhou(201803040013)。
文摘Coronavirus disease 2019(COVID-19),caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),has spread rapidly around the world,posing a major threat to human health and the economy.Currently,long-term data on viral shedding and the serum antibody responses in COVID-19 patients are still limited.Herein,we report the clinical features,viral RNA loads,and serum antibody levels in a cohort of 112 COVID-19 patients admitted to the Honghu People’s Hospital,Hubei Province,China.Overall,5.36%(6/112)of patients showed persistent viral RNA shedding(>45 days).The peak viral load was higher in the severe disease group than in the mild group(median cycle threshold value,36.4 versus 31.5;P=0.002).For most patients the disappearance of IgM antibodies occurred approximately 4–6 weeks after symptoms onset,while IgG persisted for over 194 days after the onset of symptoms,although patients showed a 46%reduction in antibodies titres against SARS-CoV-2 nucleocapsid protein compared with the acute phase.We also studied18 asymptomatic individuals with RT-qPCR confirmed SARS-CoV-2 infection together with 17 symptomatic patients,and the asymptomatic individuals were the close contacts of these symptomatic cases.Delayed IgG seroconversion and lower IgM seropositive rates were observed in asymptomatic individuals.These data indicate that higher viral loads and stronger antibody responses are related to more severe disease status in patients with SARS-CoV-2 infection,and the antibodies persisted in the recovered patient for more than 6 months so that the vaccine may provide protection against SARS-CoV-2 infection.
文摘The electrochemical reduction of carbon dioxide(CO_(2))to value-added fuels and chemicals provides a promising way to realize sustainable carbon recycling[1].Developing robust electrocatalysts with high activity and selectivity is critically important for efficient electrochemical CO_(2)reduction reaction(CO_(2)RR).Generally,it is challenging to achieve high efficiency and selectivity simultaneously in the CO_(2)RR due to the multi-proton/electron transfer processes and complex reaction intermediates.
