To gain a comprehensive understanding of sources and health risks of trace elements in an area of China with high population densities and low PM_(2.5)concentrations,15 trace elements(Al,K,Ca,Ti,V,Cr,Mn,Fe,Ni,Cu,Zn,As...To gain a comprehensive understanding of sources and health risks of trace elements in an area of China with high population densities and low PM_(2.5)concentrations,15 trace elements(Al,K,Ca,Ti,V,Cr,Mn,Fe,Ni,Cu,Zn,As,Sn,Ba,Pb)in PM_(2.5)were monitored from December 2020 to November 2021 in a representative city,Xiamen.The concentrations of trace elements in Xiamen displayed an obvious seasonal variation and were dominated by K,Fe,Al,Ca and Zn.Based on Positive Matrix Factorization analysis,source appointment revealed that the major sources of trace elements in Xiamen were traffic,dust,biomass and firework combustion,industrial manufacture and shipping emission.According to health risk assessment combined with the source appointment results,it indicated that the average noncarcinogenic risk was below the threshold and cancer risk of four hazardous metals(Cr,Ni,As,Pb)exceeded the threshold(10^(-6)).Traffic-related source had almost half amount of contribution to the health risk induced by PM_(2.5)-bound trace elements.During the dust transport period or Spring Festival period,the health risks exceeded an acceptable threshold even an order of magnitude higher,suggesting that the serious health risks still existed in low PM_(2.5)environment at certain times.Health risk assessment reminded that the health risk reduction in PM_(2.5)at southeastern China should prioritize traffic-related hazardous trace elements and highlighted the importance of controlling vehicles emissions in the future.展开更多
Improving the alkali resistance of catalysts for selective catalytic reduction of NO_(x) with NH_(3) is still a challenge.In this work,the co-modification with Fe,Ce and sulfates on V_(2)O_(5)-WO_(3)/TiO_(2) catalysts...Improving the alkali resistance of catalysts for selective catalytic reduction of NO_(x) with NH_(3) is still a challenge.In this work,the co-modification with Fe,Ce and sulfates on V_(2)O_(5)-WO_(3)/TiO_(2) catalysts(denoted as xSFeCeVWTi) significantly enhances its alkali resistance with K element as a representative.A series of xSFeCeVWTi catalysts was synthesized by wet impregnation with designed 0.05Fe/V, 1.5Ce/V and different S/V molar ratios x.The NO_(x) conversion and K resistance of xSFeCeVWTi catalysts increase with the increase of loading amounts of sulfates but no longer further increase as the sulfates load is excessive to block the pores of catalysts and hinder the adsorption of reactants.The optimal modified catalyst in about 2.2S/V actual loading ratio,corresponding to 10.5SFeCeVWTi sample,shows over 99.0%NO_(x) conversion and N_(2) selectivity at 300-400℃ after K-poisoning.The interaction between Fe,Ce and V improves its redox ability but slightly weakens surface acidity,while the proper amount of sulfate species enriches surface Br?nsted acid sites but attenuates its redox capability.However,a balance of redox capacity and surface acidity,caused by Fe,Ce and sulfate co-modification,contributes to the excellent K resistance of 10.5SFeCeVWTi catalyst.Finally,the change of physicochemical properties influences the reaction mechanism which follows the Eley-Rideal mechanism on 10.SSFeCeVWTi catalyst.These results show that the co-modification with Fe,Ce and sulfates is a good way to improve the alkali tolerance of V_(2)O_(5)-WO_(3)/TiO_(2) catalyst in industrial applications.展开更多
Three types of macromolecular organic matters （MOMs）, i.e. humic acid （HA）, kerogen＋black carbon （KB）, and black carbon （BC） were extracted from marine sediments of Xiamen Gulf, southeast of China. The chemic...Three types of macromolecular organic matters （MOMs）, i.e. humic acid （HA）, kerogen＋black carbon （KB）, and black carbon （BC） were extracted from marine sediments of Xiamen Gulf, southeast of China. The chemical composition, morphological property and source of the three extractions were characterized by elemental analyzer/isotope ratio mass spectrometry （EA/IRMS） and scanning electron microscope （SEM）. The results showed that KB was the predominant fraction in MOMs, which accounted for 61.79%-89.15% of the total organic content （TOC）, while HA consisted less than 5%. The relative high contents of kerogen and BC, and low contents of HA in the samples indicated that anthropogenic input might be the major source of organic matter in marine sediments near the industrial regions. The characterization of SEM, not only revealed morphological properties of the three fractions, but also allowed a better understanding of the source of MOMs. The δ 13 C values of the three fractions suggested that materials from terrestrial C 3 plants were predominant. Furthermore, the anthropogenic activities, such as the discharge of sewage, coal and biomass combustion from industry nearby and agricultural practices within drainage basin of the Jiulong River, were remarkably contributed to the variations in δ 13 C values of MOMs in the offshore marine sediments.展开更多
Coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS- CoV-2), is a life-threatening disease, especially in elderly individuals and those with comorbidities. The...Coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS- CoV-2), is a life-threatening disease, especially in elderly individuals and those with comorbidities. The predominant clinical manifestation of COVID-19 is respiratory dysfunction, while neurological presentations are increasingly being recognized. SARS-CoV-2 invades host cells primarily via attachment of the spike protein to the angiotensin-converting enzyme 2 (ACE2) receptor expressed on cell membranes. Patients with Alzheimer’s disease (AD) are more susceptible to SARS-CoV-2 infection and prone to severe clinical outcomes. Recent studies have revealed some common risk fac-tors for AD and COVID-19. An understanding of the association between COVID-19 and AD and the potential related mechanisms may lead to the development of novel approaches to treating both diseases. In the present review, we first summarize the mechanisms by which SARS-CoV-2 invades the central nervous system (CNS) and then discuss the associations and potential shared key factors between COVID-19 and AD, with a focus on the ACE2 receptor, apolipo-protein E (APOE) genotype, age, and neuroinflammation.展开更多
There is currently great interest in developing an environment-friendly,low-cost,and scalable approach for producing stimuli-responsive fluorescent hydrogels(FHs)with excellent mechanical property,rewritable fluoresce...There is currently great interest in developing an environment-friendly,low-cost,and scalable approach for producing stimuli-responsive fluorescent hydrogels(FHs)with excellent mechanical property,rewritable fluorescence,and dual anti-counterfeiting capabilities.Herein,by applying natural,environment-friendly,and sustainable curcumin as a responsive agent,tough pH-responsive FHs(pH-FHs)are fabricated via a facile preparation strategy.These materials have outstanding mechanical performances:ultimate stress of 180 kPa,an ultimate strain of~2500%,and good anti-fatigue performances against compression.These pH-FHs are able to sense ammonia and formaldehyde gas,resulting in both a color change and fluorescence for dual anti-counterfeiting functionality.This sensing information is stored individually by the pH-FHs and could be externally removed using formaldehyde gas to achieve a rewritable system.Our study provides valuable insights that are expected to facilitate the development of smart FHs for information encryption and anti-counterfeiting applications.展开更多
Ferroelectric-semiconductor heterostructures offer an alternative strategy to manipulate polarization towards advanced devices with engineered functionality and improved performance.In this work,we report on the heter...Ferroelectric-semiconductor heterostructures offer an alternative strategy to manipulate polarization towards advanced devices with engineered functionality and improved performance.In this work,we report on the heteroepitaxial construction,band structure alignment and polarization engineering of the single-phasedκ-Ga_(2)O_(3)/GaN ferroelectric/polar heterojunction.A type-II band alignment is determined at theκ-Ga_(2)O_(3)/GaN polar hetero-interface,with a valence band offset of(1.74±0.1)eV and a conduction band offset of(0.29■0.1)eV.Besides the band edge discontinuity,charge dipoles induced by spontaneous polarization lead to the observed band bending with built-in potentials of 0.9 and 0.33 eV,respectively,at theκ-Ga_(2)O_(3)surface andκ-Ga_(2)O_(3)/GaN interface.The polarization switching properties of ferroelectricκ-Ga_(2)O_(3)are identified with a remanent polarization of approximately 2.7μC/cm^(2)via the direct hysteresis remanent polarization/voltage(P-V)loop measurement.These findings allow the rational design ofκ-Ga_(2)O_(3)ferroelectric/polar heterojunction for the application of power electronic devices,advanced memories and even ultra-low loss negative capacitance transistors.展开更多
基金supported by the National Natural Science Foundation of China(No.U22A20578)the Science and Technology Department of Fujian Province(No.2022L3025)+3 种基金the Center for Excellence in Regional Atmospheric Environment Project(No.E0L1B20201)the Chaozhou Science and Technology Plan Project(No.2018GY03)Xiamen Atmospheric Environment Observation and Research Station of Fujian ProvinceFujian Key Laboratory of Atmospheric Ozone Pollution Prevention(Institute of Urban Environment,Chinese Academy of Sciences)。
文摘To gain a comprehensive understanding of sources and health risks of trace elements in an area of China with high population densities and low PM_(2.5)concentrations,15 trace elements(Al,K,Ca,Ti,V,Cr,Mn,Fe,Ni,Cu,Zn,As,Sn,Ba,Pb)in PM_(2.5)were monitored from December 2020 to November 2021 in a representative city,Xiamen.The concentrations of trace elements in Xiamen displayed an obvious seasonal variation and were dominated by K,Fe,Al,Ca and Zn.Based on Positive Matrix Factorization analysis,source appointment revealed that the major sources of trace elements in Xiamen were traffic,dust,biomass and firework combustion,industrial manufacture and shipping emission.According to health risk assessment combined with the source appointment results,it indicated that the average noncarcinogenic risk was below the threshold and cancer risk of four hazardous metals(Cr,Ni,As,Pb)exceeded the threshold(10^(-6)).Traffic-related source had almost half amount of contribution to the health risk induced by PM_(2.5)-bound trace elements.During the dust transport period or Spring Festival period,the health risks exceeded an acceptable threshold even an order of magnitude higher,suggesting that the serious health risks still existed in low PM_(2.5)environment at certain times.Health risk assessment reminded that the health risk reduction in PM_(2.5)at southeastern China should prioritize traffic-related hazardous trace elements and highlighted the importance of controlling vehicles emissions in the future.
基金Project supported by Fujian Provincial Department of Science and Technology,China (2020Y0085)Youth Innovation Promotion Association,Chinese Academy of Sciences (2020309)the Cultivating Project of Strategic Priority Research Program of Chinese Academy of Sciences (XDPB1902)。
文摘Improving the alkali resistance of catalysts for selective catalytic reduction of NO_(x) with NH_(3) is still a challenge.In this work,the co-modification with Fe,Ce and sulfates on V_(2)O_(5)-WO_(3)/TiO_(2) catalysts(denoted as xSFeCeVWTi) significantly enhances its alkali resistance with K element as a representative.A series of xSFeCeVWTi catalysts was synthesized by wet impregnation with designed 0.05Fe/V, 1.5Ce/V and different S/V molar ratios x.The NO_(x) conversion and K resistance of xSFeCeVWTi catalysts increase with the increase of loading amounts of sulfates but no longer further increase as the sulfates load is excessive to block the pores of catalysts and hinder the adsorption of reactants.The optimal modified catalyst in about 2.2S/V actual loading ratio,corresponding to 10.5SFeCeVWTi sample,shows over 99.0%NO_(x) conversion and N_(2) selectivity at 300-400℃ after K-poisoning.The interaction between Fe,Ce and V improves its redox ability but slightly weakens surface acidity,while the proper amount of sulfate species enriches surface Br?nsted acid sites but attenuates its redox capability.However,a balance of redox capacity and surface acidity,caused by Fe,Ce and sulfate co-modification,contributes to the excellent K resistance of 10.5SFeCeVWTi catalyst.Finally,the change of physicochemical properties influences the reaction mechanism which follows the Eley-Rideal mechanism on 10.SSFeCeVWTi catalyst.These results show that the co-modification with Fe,Ce and sulfates is a good way to improve the alkali tolerance of V_(2)O_(5)-WO_(3)/TiO_(2) catalyst in industrial applications.
基金supported by the National Natural Science Foundation of China (No.41005082)the Visiting Fellowships of State Key Laboratory of Marine Environmental Science (Xiamen University) (No.MELRS1017)
文摘Three types of macromolecular organic matters （MOMs）, i.e. humic acid （HA）, kerogen＋black carbon （KB）, and black carbon （BC） were extracted from marine sediments of Xiamen Gulf, southeast of China. The chemical composition, morphological property and source of the three extractions were characterized by elemental analyzer/isotope ratio mass spectrometry （EA/IRMS） and scanning electron microscope （SEM）. The results showed that KB was the predominant fraction in MOMs, which accounted for 61.79%-89.15% of the total organic content （TOC）, while HA consisted less than 5%. The relative high contents of kerogen and BC, and low contents of HA in the samples indicated that anthropogenic input might be the major source of organic matter in marine sediments near the industrial regions. The characterization of SEM, not only revealed morphological properties of the three fractions, but also allowed a better understanding of the source of MOMs. The δ 13 C values of the three fractions suggested that materials from terrestrial C 3 plants were predominant. Furthermore, the anthropogenic activities, such as the discharge of sewage, coal and biomass combustion from industry nearby and agricultural practices within drainage basin of the Jiulong River, were remarkably contributed to the variations in δ 13 C values of MOMs in the offshore marine sediments.
基金the National Natural Science Foundation of China(81671181)the Project funded by China Postdoctoral Science Foundation(2022M710848).
文摘Coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS- CoV-2), is a life-threatening disease, especially in elderly individuals and those with comorbidities. The predominant clinical manifestation of COVID-19 is respiratory dysfunction, while neurological presentations are increasingly being recognized. SARS-CoV-2 invades host cells primarily via attachment of the spike protein to the angiotensin-converting enzyme 2 (ACE2) receptor expressed on cell membranes. Patients with Alzheimer’s disease (AD) are more susceptible to SARS-CoV-2 infection and prone to severe clinical outcomes. Recent studies have revealed some common risk fac-tors for AD and COVID-19. An understanding of the association between COVID-19 and AD and the potential related mechanisms may lead to the development of novel approaches to treating both diseases. In the present review, we first summarize the mechanisms by which SARS-CoV-2 invades the central nervous system (CNS) and then discuss the associations and potential shared key factors between COVID-19 and AD, with a focus on the ACE2 receptor, apolipo-protein E (APOE) genotype, age, and neuroinflammation.
基金the Guangzhou Municipality Bureau of Education (201831825) for sponsoring this research
文摘There is currently great interest in developing an environment-friendly,low-cost,and scalable approach for producing stimuli-responsive fluorescent hydrogels(FHs)with excellent mechanical property,rewritable fluorescence,and dual anti-counterfeiting capabilities.Herein,by applying natural,environment-friendly,and sustainable curcumin as a responsive agent,tough pH-responsive FHs(pH-FHs)are fabricated via a facile preparation strategy.These materials have outstanding mechanical performances:ultimate stress of 180 kPa,an ultimate strain of~2500%,and good anti-fatigue performances against compression.These pH-FHs are able to sense ammonia and formaldehyde gas,resulting in both a color change and fluorescence for dual anti-counterfeiting functionality.This sensing information is stored individually by the pH-FHs and could be externally removed using formaldehyde gas to achieve a rewritable system.Our study provides valuable insights that are expected to facilitate the development of smart FHs for information encryption and anti-counterfeiting applications.
基金supported by the State Key Research and Development Project of Guangdong,China(Grant No.2020B010174002)the National Natural Science Foundation of China(Grant Nos.U21A20503,and U21A2071)。
文摘Ferroelectric-semiconductor heterostructures offer an alternative strategy to manipulate polarization towards advanced devices with engineered functionality and improved performance.In this work,we report on the heteroepitaxial construction,band structure alignment and polarization engineering of the single-phasedκ-Ga_(2)O_(3)/GaN ferroelectric/polar heterojunction.A type-II band alignment is determined at theκ-Ga_(2)O_(3)/GaN polar hetero-interface,with a valence band offset of(1.74±0.1)eV and a conduction band offset of(0.29■0.1)eV.Besides the band edge discontinuity,charge dipoles induced by spontaneous polarization lead to the observed band bending with built-in potentials of 0.9 and 0.33 eV,respectively,at theκ-Ga_(2)O_(3)surface andκ-Ga_(2)O_(3)/GaN interface.The polarization switching properties of ferroelectricκ-Ga_(2)O_(3)are identified with a remanent polarization of approximately 2.7μC/cm^(2)via the direct hysteresis remanent polarization/voltage(P-V)loop measurement.These findings allow the rational design ofκ-Ga_(2)O_(3)ferroelectric/polar heterojunction for the application of power electronic devices,advanced memories and even ultra-low loss negative capacitance transistors.
