Air concentrations of volatile organic compounds(VOCs) were continually measured at a monitoring site in Shenyang from 20 August to 16 September 2017. The average concentrations of alkanes, alkenes, aromatics and carb...Air concentrations of volatile organic compounds(VOCs) were continually measured at a monitoring site in Shenyang from 20 August to 16 September 2017. The average concentrations of alkanes, alkenes, aromatics and carbonyls were 28.54, 6.30, 5.59 and9.78 ppbv, respectively. Seven sources were identified by the Positive Matrix Factorization model based on the measurement data of VOCs and CO. Vehicle exhaust contributed the most(36.15%) to the total propene-equivalent concentration of the measured VOCs,followed by combustion emission(16.92%), vegetation emission and secondary formation(14.33%), solvent usage(10.59%), petrochemical industry emission(9.89%), petrol evaporation(6.28%), and liquefied petroleum gas(LPG) usage(5.84%). Vehicle exhaust, solvent usage and combustion emission were found to be the top three VOC sources for O_3 formation potential, accounting for 34.52%, 16.55% and 11.94%, respectively. The diurnal variation of the total VOCs from each source could be well explained by their emission characteristics,e.g., the two peaks of VOC concentrations from LPG usage were in line with the cooking times for breakfast and lunch. Wind rose plots of the VOCs from each source could reveal the possible distribution of the sources around the monitoring site. The O_3 pollution episodes during the measurement period were found to be coincident with the elevation of VOCs, which was mainly due to the air parcel from the southeast direction where petrochemical industry emission was found to be dominant, suggesting that the petrochemical industry emission from the southeast was probably a significant cause of O_3 pollution in Shenyang.展开更多
MicroRNA-132(miR-132), a small RNA that regulates gene expression, is known to promote neurogenesis in the embryonic nervous system and adult brain.Although exposure to psychoactive substances can increase miR-132 exp...MicroRNA-132(miR-132), a small RNA that regulates gene expression, is known to promote neurogenesis in the embryonic nervous system and adult brain.Although exposure to psychoactive substances can increase miR-132 expression in cultured neural stem cells(NSCs)and the adult brain of rodents, little is known about its role in opioid addiction. So, we set out to determine the effect of miR-132 on differentiation of the NSCs and whether this effect is involved in opioid addiction using the rat morphine self-administration(MSA) model. We found that miR-132 overexpression enhanced the differentiation of NSCs in vivo and in vitro. Similarly, speci?c overexpression of miR-132 in NSCs of the adult hippocampal dentate gyrus(DG) during the acquisition stage of MSA potentiated morphine-seeking behavior. These ?ndings indicate that miR-132 is involved in opioid addiction,probably by promoting the differentiation of NSCs in the adult DG.展开更多
As an important secondary photochemical pollutant,peroxyacetyl nitrate(PAN)has been studied over decades,yet its simulations usually underestimate the corresponding observations,especially in polluted areas.Recent obs...As an important secondary photochemical pollutant,peroxyacetyl nitrate(PAN)has been studied over decades,yet its simulations usually underestimate the corresponding observations,especially in polluted areas.Recent observations in north China found unusually high concentrations of PAN during wintertime heavy haze events,but the current model still cannot reproduce the observations,and researchers speculated that nitrous acid(HONO)played a key role in PAN formation.For the first time we systematically assessed the impact of potential HONO sources on PAN formation mechanisms in eastern China using the Weather Research and Forecasting/Chemistry(WRF-Chem)model in February of 2017.The results showed that the potential HONO sources significantly improved the PAN simulations,remarkably accelerated the RO x(sum of hydroxyl,hydroperoxyl,and organic peroxy radicals)cycles,and resulted in 80%–150%enhancements of PAN near the ground in the coastal areas of eastern China and 10%–50%enhancements in the areas around 35–40°N within 3 km during a heavy haze period.The direct precursors of PAN were aldehyde and methylglyoxal,and the primary precursors of PAN were alkenes with C>3,xylenes,propene and toluene.The above results suggest that the potential HONO sources should be considered in regional and global chemical transport models when conducting PAN studies.展开更多
Sulfate aerosol contributes to particulate matter pollution and plays a key role in aerosol radiative forcing,impacting human health and climate change.Atmospheric models tend to substantially underestimate sulfate co...Sulfate aerosol contributes to particulate matter pollution and plays a key role in aerosol radiative forcing,impacting human health and climate change.Atmospheric models tend to substantially underestimate sulfate concentrations during haze episodes,indicating that there are still missing mechanisms not considered by the models.Despite recent good progress in understanding the missing sulfate sources,knowledge on different sulfate formation pathways during polluted periods still involves large uncertainties and the dominant mechanism is under heated debate,calling for more field,laboratory,and modeling work.Here,we review the traditional sulfate formation mechanisms in cloud water and also discuss the potential factors affecting multiphase S(Ⅳ)oxidation.Then recent progress in multiphase S(Ⅳ)oxidation mechanisms is summarized.Sulfate formation rates by different prevailing oxidation pathways under typical winter-haze conditions are also calculated and compared.Based on the literature reviewed,we put forward control of the atmospheric oxidation capacity as a means to abate sulfate aerosol pollution.Finally,we conclude with a concise set of research priorities for improving our understanding of sulfate formation mechanisms during polluted periods.展开更多
The pollution levels,composition characteristics and sources of atmospheric PM2.5 were investigated based on field measurement at a rural site in the North China Plain(NCP) from pre-heating period to heating period in...The pollution levels,composition characteristics and sources of atmospheric PM2.5 were investigated based on field measurement at a rural site in the North China Plain(NCP) from pre-heating period to heating period in winter of 2017.The hourly average concentrations of PM2.5 frequently exceeded 150 μg/m3 and even achieved 400 μg/m3,indicating that the PM2.5pollution was still very serious despite the implementation of stricter control measures in the rural area.Compared with the pre-heating period,the mean concentrations of organic carbon(OG),element carbon(EC) and chlorine ion(Cl-) during the heating period increased by 20.8%,36.6% and 38.8%,accompanying with increments of their proportions in PM2.5from 37.5%,9.8% and 5.5% to 42.9%,12.7% and 7.2%,respectively.The significant increase of both their concentrations and proportions during the heating period was mainly ascribed to the residential coal combustion.The proportions of sulfate,nitrate and ammonium respectively increased from 9.9%,10.9% and 9.0% in nighttime to 13.8%,16.2% and 11.1% in daytime,implying that the daytime photochemical reactions made remarkable contributions to the secondary inorganic aerosols.The simulation results from WRF-Chem revealed that the emission of residential coal combustion in the rural area was underestimated by the current emission inventory.Six sources identified by positive matrix factorization(PMF) based on the measurement were residential coal combustion,secondary formation of inorganic aerosols,biomass burning,vehicle emission and raising dust,contributing to atmospheric PM2.5 of 40.5%,21.2%,16.4%,10.8%,8.6% and 2.5%,respectively.展开更多
The efficient maintenance of the activity of excised branches is the powerful guarantee to accurately determine gas exchange flux between the detached branches of tall trees and the atmosphere. In this study, the net ...The efficient maintenance of the activity of excised branches is the powerful guarantee to accurately determine gas exchange flux between the detached branches of tall trees and the atmosphere. In this study, the net photosynthetic rate(NPR) of the excised branches and branches in situ were measured simultaneously by using two photosynthetic instruments to characterize the activity of the excised branches of Phyllostachys nigra. The ratio of normalized NPR of excised branches to NPR in situ was used to assess the photosynthetic activity of detached branches. Based on photosynthetic activity, an optimal hydroponics protocol for maintaining activity of excised P. nigra branches was presented:1/8 times the concentration of Gamborg B5 vitamin mixture with p H = 6. Under the best cultivation protocol, photosynthetic activity of excised P. nigra branches could be maintained more than 90% within 6 hr in the light intensity range of 200–2000 μmol/(m2·sec) and temperature range of 13.4–28.7°C. The nitrogen dioxide(NO2) flux differences between in situ and in vitro branches and the atmosphere were compared using double dynamic chambers.Based on the maintenance method of excised branches, the NO2 exchange flux between the excised P. nigra branches and the atmosphere(from-1.01 to-2.72 nmol/(m2·sec) was basically consistent with between the branches in situ and the atmosphere(from-1.12 to-3.16 nmol/(m2 sec)) within 6 hr. Therefore, this study provided a feasible protocol for in vitro measurement of gas exchange between tall trees and the atmosphere for a period of time.展开更多
The hypoxic microenvironment is an essential characteristic of most malignant tu-mors.Notably,hypoxia-inducible factor-1 alpha(HIF-1a)is a key regulatory factor of cellular adaptation to hypoxia,and many critical path...The hypoxic microenvironment is an essential characteristic of most malignant tu-mors.Notably,hypoxia-inducible factor-1 alpha(HIF-1a)is a key regulatory factor of cellular adaptation to hypoxia,and many critical pathways are correlated with the biological activity of organisms via HIF-1a.In the intra-tumoral hypoxic environment,HIF-1αis highly expressed and contributes to the malignant progression of tumors,which in turn results in a poor prog-nosis in patients.Recently,it has been indicated that HiF-1αinvolves in various critical pro-cesses of life events and tumor development via regulating the expression of HiF-1a target genes,such as cell proliferation and apoptosis,angiogenesis,glucose metabolism,immune response,therapeutic resistance,etc.Apart from solid tumors,accumulating evidence has re-vealed that HiF-1αis also closely associated with the development and progression of hemato-logical malignancies,such as leukemia,lymphoma,and multiple myeloma.Targeted inhibition of HiF-1a can facilitate an increased sensitivity of patients with malignancies to relevant ther-apeutic agents.In the review,we elaborated on the basic structure and biological functions of HIF-1a and summarized their current role in various malignancies.It is expected that they will have future potential fortargeted therapy.展开更多
The mechanisms that produce atmospheric sulfate,a critical PM_(2.5)constituent,must be elucidated to inform air quality interventions.Current evidence indicates that manganese-catalyzed heterogeneous SO_(2)oxidation i...The mechanisms that produce atmospheric sulfate,a critical PM_(2.5)constituent,must be elucidated to inform air quality interventions.Current evidence indicates that manganese-catalyzed heterogeneous SO_(2)oxidation is a dominant sulfate source.We demonstrate that black carbon(BC)critically enhances this process through interfacial electronic interactions with HSO_(3)^(-)/SO_(3)^(2-)species,reducing SO_(2)oxidation barriers while increasing reactive oxygen species(ROS)generation(1O_(2),·O_(2)^(-),and·OH).Unique sulfur isotopic signatures measured in BC-Mn^(2+)/O_(2)systems confirm a novel oxidation pathway in which BC facilitates electron transfer during O_(2)^(-)activated SO_(2)conversion.Multiphase modeling revealed that under typical haze conditions,BC-mediated catalysis produces sulfate at higher rates than traditional Mn-only pathways.The synergistic BC-Mn system enables continuous redox cycling via O_(2)activation,establishing BC as an active electronic modulator rather than a passive substrate in sulfate formation.These findings redefine the role of BC in atmospheric chemistry,offering a molecular basis for targeted sulfate aerosol control.展开更多
基金supported by the National Key Research and Development Program of China(Nos.2016YFC0202200,2017YFC0209703)the National Natural Science Foundation of China(Nos.91544211,4127805,41575121,21707151)the National research program for Key issues in air pollution control(Nos.DQGG0103,DQGG0206,DQGG0209)
文摘Air concentrations of volatile organic compounds(VOCs) were continually measured at a monitoring site in Shenyang from 20 August to 16 September 2017. The average concentrations of alkanes, alkenes, aromatics and carbonyls were 28.54, 6.30, 5.59 and9.78 ppbv, respectively. Seven sources were identified by the Positive Matrix Factorization model based on the measurement data of VOCs and CO. Vehicle exhaust contributed the most(36.15%) to the total propene-equivalent concentration of the measured VOCs,followed by combustion emission(16.92%), vegetation emission and secondary formation(14.33%), solvent usage(10.59%), petrochemical industry emission(9.89%), petrol evaporation(6.28%), and liquefied petroleum gas(LPG) usage(5.84%). Vehicle exhaust, solvent usage and combustion emission were found to be the top three VOC sources for O_3 formation potential, accounting for 34.52%, 16.55% and 11.94%, respectively. The diurnal variation of the total VOCs from each source could be well explained by their emission characteristics,e.g., the two peaks of VOC concentrations from LPG usage were in line with the cooking times for breakfast and lunch. Wind rose plots of the VOCs from each source could reveal the possible distribution of the sources around the monitoring site. The O_3 pollution episodes during the measurement period were found to be coincident with the elevation of VOCs, which was mainly due to the air parcel from the southeast direction where petrochemical industry emission was found to be dominant, suggesting that the petrochemical industry emission from the southeast was probably a significant cause of O_3 pollution in Shenyang.
基金supported by grants from the National Natural Science Foundation(81471353 and 81771433)the National Basic Research Development Program of China(2015CB553500)the Science Fund for Creative Research Groups from the National Natural Science Foundation of China(81521063)
文摘MicroRNA-132(miR-132), a small RNA that regulates gene expression, is known to promote neurogenesis in the embryonic nervous system and adult brain.Although exposure to psychoactive substances can increase miR-132 expression in cultured neural stem cells(NSCs)and the adult brain of rodents, little is known about its role in opioid addiction. So, we set out to determine the effect of miR-132 on differentiation of the NSCs and whether this effect is involved in opioid addiction using the rat morphine self-administration(MSA) model. We found that miR-132 overexpression enhanced the differentiation of NSCs in vivo and in vitro. Similarly, speci?c overexpression of miR-132 in NSCs of the adult hippocampal dentate gyrus(DG) during the acquisition stage of MSA potentiated morphine-seeking behavior. These ?ndings indicate that miR-132 is involved in opioid addiction,probably by promoting the differentiation of NSCs in the adult DG.
基金This work was partially supported by the National Key Research and Development Program of China(No.2017YFC0209801)the National Natural Science Foundation of China(Nos.91544221,41575124)the National Research Program for Key Issues in Air Pollution Control(Nos.DQGG0102,DQGG0103).
文摘As an important secondary photochemical pollutant,peroxyacetyl nitrate(PAN)has been studied over decades,yet its simulations usually underestimate the corresponding observations,especially in polluted areas.Recent observations in north China found unusually high concentrations of PAN during wintertime heavy haze events,but the current model still cannot reproduce the observations,and researchers speculated that nitrous acid(HONO)played a key role in PAN formation.For the first time we systematically assessed the impact of potential HONO sources on PAN formation mechanisms in eastern China using the Weather Research and Forecasting/Chemistry(WRF-Chem)model in February of 2017.The results showed that the potential HONO sources significantly improved the PAN simulations,remarkably accelerated the RO x(sum of hydroxyl,hydroperoxyl,and organic peroxy radicals)cycles,and resulted in 80%–150%enhancements of PAN near the ground in the coastal areas of eastern China and 10%–50%enhancements in the areas around 35–40°N within 3 km during a heavy haze period.The direct precursors of PAN were aldehyde and methylglyoxal,and the primary precursors of PAN were alkenes with C>3,xylenes,propene and toluene.The above results suggest that the potential HONO sources should be considered in regional and global chemical transport models when conducting PAN studies.
基金supported by the National Key Research and Development Program of China(No.2019YFC0214801)the China Postdoctoral Science Foundation(Nos.2021M700214 and 2022T150011)。
文摘Sulfate aerosol contributes to particulate matter pollution and plays a key role in aerosol radiative forcing,impacting human health and climate change.Atmospheric models tend to substantially underestimate sulfate concentrations during haze episodes,indicating that there are still missing mechanisms not considered by the models.Despite recent good progress in understanding the missing sulfate sources,knowledge on different sulfate formation pathways during polluted periods still involves large uncertainties and the dominant mechanism is under heated debate,calling for more field,laboratory,and modeling work.Here,we review the traditional sulfate formation mechanisms in cloud water and also discuss the potential factors affecting multiphase S(Ⅳ)oxidation.Then recent progress in multiphase S(Ⅳ)oxidation mechanisms is summarized.Sulfate formation rates by different prevailing oxidation pathways under typical winter-haze conditions are also calculated and compared.Based on the literature reviewed,we put forward control of the atmospheric oxidation capacity as a means to abate sulfate aerosol pollution.Finally,we conclude with a concise set of research priorities for improving our understanding of sulfate formation mechanisms during polluted periods.
基金supported by the National Natural Science Foundation of China(Nos.91544211,41727805,41575121,and 21707151)the National research program for Key issues in air pollution control(Nos.DQGG0103,DQGG0209,and DQGG0206)+1 种基金the National Key Research and Development Program of China(Nos.2016YFC0202200,2017YFC0209703,and 2017YFF0108301)Key Laboratory of Atmospheric Chemistry,China Meteorological Administration(No.2018B03)
文摘The pollution levels,composition characteristics and sources of atmospheric PM2.5 were investigated based on field measurement at a rural site in the North China Plain(NCP) from pre-heating period to heating period in winter of 2017.The hourly average concentrations of PM2.5 frequently exceeded 150 μg/m3 and even achieved 400 μg/m3,indicating that the PM2.5pollution was still very serious despite the implementation of stricter control measures in the rural area.Compared with the pre-heating period,the mean concentrations of organic carbon(OG),element carbon(EC) and chlorine ion(Cl-) during the heating period increased by 20.8%,36.6% and 38.8%,accompanying with increments of their proportions in PM2.5from 37.5%,9.8% and 5.5% to 42.9%,12.7% and 7.2%,respectively.The significant increase of both their concentrations and proportions during the heating period was mainly ascribed to the residential coal combustion.The proportions of sulfate,nitrate and ammonium respectively increased from 9.9%,10.9% and 9.0% in nighttime to 13.8%,16.2% and 11.1% in daytime,implying that the daytime photochemical reactions made remarkable contributions to the secondary inorganic aerosols.The simulation results from WRF-Chem revealed that the emission of residential coal combustion in the rural area was underestimated by the current emission inventory.Six sources identified by positive matrix factorization(PMF) based on the measurement were residential coal combustion,secondary formation of inorganic aerosols,biomass burning,vehicle emission and raising dust,contributing to atmospheric PM2.5 of 40.5%,21.2%,16.4%,10.8%,8.6% and 2.5%,respectively.
基金supported by projects of the National Key Research and Development of China (No. 2017YFC0209700)the National Natural Science Foundation of China (Nos. 41575121, 91544211, 41727805, 21477142)
文摘The efficient maintenance of the activity of excised branches is the powerful guarantee to accurately determine gas exchange flux between the detached branches of tall trees and the atmosphere. In this study, the net photosynthetic rate(NPR) of the excised branches and branches in situ were measured simultaneously by using two photosynthetic instruments to characterize the activity of the excised branches of Phyllostachys nigra. The ratio of normalized NPR of excised branches to NPR in situ was used to assess the photosynthetic activity of detached branches. Based on photosynthetic activity, an optimal hydroponics protocol for maintaining activity of excised P. nigra branches was presented:1/8 times the concentration of Gamborg B5 vitamin mixture with p H = 6. Under the best cultivation protocol, photosynthetic activity of excised P. nigra branches could be maintained more than 90% within 6 hr in the light intensity range of 200–2000 μmol/(m2·sec) and temperature range of 13.4–28.7°C. The nitrogen dioxide(NO2) flux differences between in situ and in vitro branches and the atmosphere were compared using double dynamic chambers.Based on the maintenance method of excised branches, the NO2 exchange flux between the excised P. nigra branches and the atmosphere(from-1.01 to-2.72 nmol/(m2·sec) was basically consistent with between the branches in situ and the atmosphere(from-1.12 to-3.16 nmol/(m2 sec)) within 6 hr. Therefore, this study provided a feasible protocol for in vitro measurement of gas exchange between tall trees and the atmosphere for a period of time.
基金supported by the National Natural Science Foundation of China(No.82070175)the Natural Science Foundation of Hunan Province(No.2022JJ30830)the Scientific Program of the Health Commission of Hunan Province(China)(No.20201179).
文摘The hypoxic microenvironment is an essential characteristic of most malignant tu-mors.Notably,hypoxia-inducible factor-1 alpha(HIF-1a)is a key regulatory factor of cellular adaptation to hypoxia,and many critical pathways are correlated with the biological activity of organisms via HIF-1a.In the intra-tumoral hypoxic environment,HIF-1αis highly expressed and contributes to the malignant progression of tumors,which in turn results in a poor prog-nosis in patients.Recently,it has been indicated that HiF-1αinvolves in various critical pro-cesses of life events and tumor development via regulating the expression of HiF-1a target genes,such as cell proliferation and apoptosis,angiogenesis,glucose metabolism,immune response,therapeutic resistance,etc.Apart from solid tumors,accumulating evidence has re-vealed that HiF-1αis also closely associated with the development and progression of hemato-logical malignancies,such as leukemia,lymphoma,and multiple myeloma.Targeted inhibition of HiF-1a can facilitate an increased sensitivity of patients with malignancies to relevant ther-apeutic agents.In the review,we elaborated on the basic structure and biological functions of HIF-1a and summarized their current role in various malignancies.It is expected that they will have future potential fortargeted therapy.
基金supported by the National Science Fund for Distinguished Young Scholars(22325601)the National Natural Science Foundation of China(42473024,51908294,and 21976006)。
文摘The mechanisms that produce atmospheric sulfate,a critical PM_(2.5)constituent,must be elucidated to inform air quality interventions.Current evidence indicates that manganese-catalyzed heterogeneous SO_(2)oxidation is a dominant sulfate source.We demonstrate that black carbon(BC)critically enhances this process through interfacial electronic interactions with HSO_(3)^(-)/SO_(3)^(2-)species,reducing SO_(2)oxidation barriers while increasing reactive oxygen species(ROS)generation(1O_(2),·O_(2)^(-),and·OH).Unique sulfur isotopic signatures measured in BC-Mn^(2+)/O_(2)systems confirm a novel oxidation pathway in which BC facilitates electron transfer during O_(2)^(-)activated SO_(2)conversion.Multiphase modeling revealed that under typical haze conditions,BC-mediated catalysis produces sulfate at higher rates than traditional Mn-only pathways.The synergistic BC-Mn system enables continuous redox cycling via O_(2)activation,establishing BC as an active electronic modulator rather than a passive substrate in sulfate formation.These findings redefine the role of BC in atmospheric chemistry,offering a molecular basis for targeted sulfate aerosol control.
