Mean platelet volume （MPV） is an early marker ofplatelet activation. Larger platelets, compared to small ones, increase platelet adhesion and aggregation, and present a higher thrombotic activity. Some studies have ...Mean platelet volume （MPV） is an early marker ofplatelet activation. Larger platelets, compared to small ones, increase platelet adhesion and aggregation, and present a higher thrombotic activity. Some studies have explored the association between MPV and the morbidity of portal vein thrombosis （PVT）. The aim of this study was to evaluate the predictive effect of MPV in patients with PVT by a meta-analysis. We searched Pubmed, Web of Science, SCOPUS, OVID, CNKI and CBMD from database inception to September 13, 2017. Seven studies in accordance with selection criteria were included. The extraction of basic data was independently conducted by two reviewers. The mean difference in MPV between PVT patients and controls were pooled with weighted mean difference （WMD） and 95% confidence interval of 0.88 fl （95% CI： 0.61-1.15）. A random-effect model was chosen for an obvious heterogeneity in the pooling （Chi-square=27.12, df=6, P〈0.0001, F=77.9%）. The sources of heterogeneity were from the difference of primary disease of participants and portal vein diameter. Taken together, our results reveal that MPV is a predictive indicator in patients with PVT.展开更多
Drug-induced liver injury(DILI),which refers to liver damage caused by a drug or its metabolites,has emerged as an important cause of acute liver failure(ALF)in recent years.Chemically-induced ALF in animal models mim...Drug-induced liver injury(DILI),which refers to liver damage caused by a drug or its metabolites,has emerged as an important cause of acute liver failure(ALF)in recent years.Chemically-induced ALF in animal models mimics the pathology of DILI in humans;thus,these models are used to study the mechanism of potentially effective treatment strategies.Mesenchymal stromal cells(MSCs)possess immunomodulatory properties,and they alleviate acute liver injury and decrease the mortality of animals with chemically-induced ALF.Here,we summarize some of the existing research on the interaction between MSCs and immune cells,and discuss the possible mechanisms underlying the immunomodulatory activity of MSCs in chemically-induced ALF.We conclude that MSCs can impact the phenotype and function of macrophages,as well as the differentiation and maturation of dendritic cells,and inhibit the proliferation and activation of T lymphocytes or B lymphocytes.MSCs also have immunomodulatory effects on the production of cytokines,such as prostaglandin E2 and tumor necrosis factor-alpha-stimulated gene 6,in animal models.Thus,MSCs have significant benefits in the treatment of chemically-induced ALF by interacting with immune cells and they may be applied to DILI in humans in the near future.展开更多
The embryos of maize(Zea mays L.)inbred lines GS02,GS07,GS08,GS11 and GS15 were used as receptor materials to optimize the receptor system from the aspects of genotype,medium components and stress(PEG6000,mannitol,sal...The embryos of maize(Zea mays L.)inbred lines GS02,GS07,GS08,GS11 and GS15 were used as receptor materials to optimize the receptor system from the aspects of genotype,medium components and stress(PEG6000,mannitol,salt and low phosphorus).The results showed that GS07 had the highest induction rate(95.2%).Orthogonal test analysis showed that the best combination of medium components in induction was A2B3C1D3(2),namely,the concentration of 2,4-dichlorophenoxy acetic acid(2,4-D)was 4 mg·mL^(-1),the concentration of L-Proline(L-Pro)was 0.8 mg·mL^(-1),and the concentration of silver nitrate(AgNO3)was 10 mg·mL^(-1)(or 5 mg·mL).Interestingly,we found that the optimal medium supplemented with 30 g·L^(-1)PEG6000 or 80 g·L^(-1)mannitol was suitable for antioxidant enzyme activity and malondialdehyde(MDA)content in GS07 callus.Exogenous 10 mmol·L^(-1)Ca^(2+)in the medium components with 100 mmol·L^(-1)sodium chloride(NaCl)could improve the activity of antioxidant enzymes in GS07 callus.Callus of GS07 could divide normally and grow well in medium components with 27 mg·L^(-1)KH_(2)PO_(4).This study enhanced the adaptability of maize callus to stress and optimized the culture conditions.展开更多
Skeletal tissue is highly innervated.Although different types of nerves have been recently identified in the bone,the crosstalk between bone and nerves remains unclear.In this review,we outline the role of the periphe...Skeletal tissue is highly innervated.Although different types of nerves have been recently identified in the bone,the crosstalk between bone and nerves remains unclear.In this review,we outline the role of the peripheral nervous system(PNS)in bone regeneration following injury.We first introduce the conserved role of nerves in tissue regeneration in species ranging from amphibians to mammals.We then present the distribution of the PNS in the skeletal system under physiological conditions,fractures,or regeneration.Furthermore,we summarize the ways in which the PNS communicates with bone-lineage cells,the vasculature,and immune cells in the bone microenvironment.Based on this comprehensive and timely review,we conclude that the PNS regulates bone regeneration through neuropeptides or neurotransmitters and cells in the peripheral nerves.An in-depth understanding of the roles of peripheral nerves in bone regeneration will inform the development of new strategies based on bone-nerve crosstalk in promoting bone repair and regeneration.展开更多
Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has posed a serious challenge to emergency departments that usually encounter emergencies and severe diseases.[1-5]Angiotensin-converting enzyme 2(ACE2),a pro...Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has posed a serious challenge to emergency departments that usually encounter emergencies and severe diseases.[1-5]Angiotensin-converting enzyme 2(ACE2),a protein that interacts with the viral spike protein(s),allows SARS-CoV-2 to penetrate epithelial cells.[6]There is mounting evidence that suggests that the digestive system may also be affected.[7]An observational study described potential patterns of pancreatic injury(elevated amylase and lipase)in patients with coronavirus disease 2019(COVID-19).[8]Additionally,sporadic case reports have described secondary pancreatitis in patients with SARS-CoV-2 infection and presented imaging evidence.[9]Moreover,a previous study showed that COVID-19 patients not only have a higher risk of developing acute pancreatitis(AP),but also have a significantly higher mortality than those without COVID-19.[10]Using bioinformatics analysis,it may be possible to reveal how COVID-19 and AP are related.In this study,two RNA-seq datasets of SARS-CoV-2 and AP were selected for analysis.展开更多
Glufosinate-ammonium herbicides are the most widely used broad-spectrum,non-selective herbicides in the world.Glufosinate-ammonium is a structural analogue of glutamate(Glu)which can irreversibly inhibit the activity ...Glufosinate-ammonium herbicides are the most widely used broad-spectrum,non-selective herbicides in the world.Glufosinate-ammonium is a structural analogue of glutamate(Glu)which can irreversibly inhibit the activity of glutamine synthetase(GS)and Glu decarboxylase in plants,thereby blocking the synthesis of glutamine(Gln)from Glu and ammonia(Hoerlein,1994).This causes the plants to die because of the nitrogen metabolism disorder and subsequent intracellular accumulation of ammonia.In humans,the characteristic features of glufosinate-ammonium herbicide poisoning include gastrointestinal symptoms and neurotoxicity(Watanabe and Sano,1998).展开更多
A rat model of middle cerebral artery permanent occlusion was established using the modified Longa method. Successfully established model animals were treated by blood-letting puncture at twelve Jing-Well points of th...A rat model of middle cerebral artery permanent occlusion was established using the modified Longa method. Successfully established model animals were treated by blood-letting puncture at twelve Jing-Well points of the hand, and/or by injecting mannitol into the caudal vein twice daily. Brain tissue was collected at 24, 48 and 72 hours after modeling, and blood was collected through the retinal vein before Evans blue was injected, approximately 1 hour prior to harvesting of brain tissue. Results showed that Evans blue leakage into brain tissue and serum nitric oxide synthase activity were significantly increased in model rats. Treatment with blood-letting punctures at twelve Jing-Well points of the hand and/or injection of mannitol into the caudal vein reduced the amount of Evans blue leakage into the brain tissue and serum nitric oxide synthase activity to varying degrees. There was no significant difference between single treatment and combined treatment. Experimental findings indicate that blood-letting punctures at twelve Jing-Well points of the hand can decrease blood-brain barrier permeability and serum nitric oxide synthase activity in rats following middle cerebral artery occlusion, and its effect is similar to that of mannitol injection alone and Jing-Well points plus mannitol injection.展开更多
Objective:To study the compounds isolated from Penicillium HDS-Z-1E,an endophytic fungal strain isolated from Taxus cuspidata and their activation effect of catalase(CAT).Methods:The chemical constituents were isolate...Objective:To study the compounds isolated from Penicillium HDS-Z-1E,an endophytic fungal strain isolated from Taxus cuspidata and their activation effect of catalase(CAT).Methods:The chemical constituents were isolated from Penicillium HDS-Z-1E,by using silica gel,Sephadex LH-20 and HPLC.The structural elucidations of five metabolites were elucidated on the basis of spectroscopic including 1 H-NMR,13C-NMR,HMBC and HSQC.Their activation sites of catalase have been investigated by molecular docking.Results:Five metabolites,compounds(1–5)were isolated from Penicillium HDS-Z-1E and identified as 4-hydroxy-4-methyltetrahydro-2H-pyran-2-one(1),4-hydroxymethyl-5,6-dihydro-pyran-2-one(2),5,6-dihydro-2-oxo-2H-pyran-4-carboxylic(3),N-acetyl-hydrazinobenzoic acid(4),and methyl 2-(2,5-dihydroxyphenyl)acetate(5).Conclusion:Compound 3 is a new compound.Compounds 3 and 4 may have potential activators of catalase,providing a theoretical basis for the development of CAT activators.展开更多
Central Plains region of China,represented by Henan Province,is facing serious air pollution problems.Vehicular exhaust emissions had adverse impacts on the atmospheric environment.The first comprehensive and novel ve...Central Plains region of China,represented by Henan Province,is facing serious air pollution problems.Vehicular exhaust emissions had adverse impacts on the atmospheric environment.The first comprehensive and novel vehicle emission inventory for Henan Province using vehicle kilometers traveled,localized emission factors,and activity data at city-level was developed.Furthermore,3 km×3 km gridded emission and temporal variations were determined by using localized information.Results show that the total emissions of sulfur dioxide(SO2),nitrogen oxides(NOx),carbon monoxide(CO),particular matter with aerodynamic diameter<10μm(PM10),aerodynamic diameter<2.5μm(PM2.5),volatile organic compounds(VOCs),VOCs-evaporation and ammonia in 2015 were 9.1,533.4,1190.7,23.7,21.6,150.8,31.5 and 10.4 Gg,respectively,and the emission intensities of the above pollutants were 0.05,2.7,6.0,0.1,0.1,0.8,0.2 and 0.05 g/km,respectively.Vehicles meeting the Primary China 1,China 3 and China 4 contributed 89.1%,82.7%,75.3%,75.5%,75.5%,68.2%,68.4%and 82.3%for SO2,NOx,CO,PM10,PM2.5,VOCs,VOCs-evaporation and ammonia emissions,respectively.Zhengzhou,Zhoukou,Nanyang,Luoyang,Shangqiu and Xinyang showed relatively higher emissions and contributed more than 50%of each pollutant.The spatial distribution indicated obvious characteristics of the road network,and high-level emission was concentrated in the downtown areas.Additionally,the ozone formation potential(OFP)based on the estimated speciated VOC emissions was 569.6 Gg in Henan Province.Aliphatic and aromatic hydrocarbons were the main species of VOCs,whereas olefins contributed the largest proportion of OFP,with 42.2%.展开更多
In this study,we conducted an observation experiment from May 1 to June 30,2018 in Zhengzhou,a major city in central China,where ground ozone(O3)pollution has become serious in recent years.The concentrations of O3 an...In this study,we conducted an observation experiment from May 1 to June 30,2018 in Zhengzhou,a major city in central China,where ground ozone(O3)pollution has become serious in recent years.The concentrations of O3 and its precursors,as well as H2O_(2) and meteorological data were obtained from the urban site(Yanchang,YC),suburban(Zhengzhou University,ZZU)and background sites(Ganglishuiku,GLSK).Result showed that the rates of O3 concentration exceeded Chinese National Air Quality Standard GradeⅡ(93.3 ppbv)were 59.0%,52.5%,and 55.7%at the above three sites with good consistency,respectively,indicating that O3 pollution is a regional problem in Zhengzhou.The daily peak O3 appeared at 15:00-16:00,which was opposite to VOCs,NOx,and CO and consistent with H2O_(2).The exhaustive statistical analysis of meteorological factors and chemical effects on O3 formation at YC was advanced.The high concentration of precursors,high temperature,low relative humidity,and moderately high wind speed together with the wind direction dominated by south and southeast wind contribute to urban O3 episodes in Zhengzhou.O3 formation analysis showed that reactive alkenes such as isoprene and cis-2-butene contributed most to O3 formation.The VOCs/NOx ratio and smog production model were used to determine O3-VOC-NOx sensitivity.The O3 formation in Zhengzhou during early summer was mainly under VOC-limited and transition regions alternately,which implies that the simultaneous emission reduction of alkenes and NOx is effective in reducing O3 pollution in Zhengzhou.展开更多
基金This work was supported by the National Natural Science Foundation of China （No. 81500109）.
文摘Mean platelet volume （MPV） is an early marker ofplatelet activation. Larger platelets, compared to small ones, increase platelet adhesion and aggregation, and present a higher thrombotic activity. Some studies have explored the association between MPV and the morbidity of portal vein thrombosis （PVT）. The aim of this study was to evaluate the predictive effect of MPV in patients with PVT by a meta-analysis. We searched Pubmed, Web of Science, SCOPUS, OVID, CNKI and CBMD from database inception to September 13, 2017. Seven studies in accordance with selection criteria were included. The extraction of basic data was independently conducted by two reviewers. The mean difference in MPV between PVT patients and controls were pooled with weighted mean difference （WMD） and 95% confidence interval of 0.88 fl （95% CI： 0.61-1.15）. A random-effect model was chosen for an obvious heterogeneity in the pooling （Chi-square=27.12, df=6, P〈0.0001, F=77.9%）. The sources of heterogeneity were from the difference of primary disease of participants and portal vein diameter. Taken together, our results reveal that MPV is a predictive indicator in patients with PVT.
基金National Natural Science Foundation of China,No.81971756and Stem Cell and Translational Research from National Key Research and Development Program of China,No.2016YFA0101001.
文摘Drug-induced liver injury(DILI),which refers to liver damage caused by a drug or its metabolites,has emerged as an important cause of acute liver failure(ALF)in recent years.Chemically-induced ALF in animal models mimics the pathology of DILI in humans;thus,these models are used to study the mechanism of potentially effective treatment strategies.Mesenchymal stromal cells(MSCs)possess immunomodulatory properties,and they alleviate acute liver injury and decrease the mortality of animals with chemically-induced ALF.Here,we summarize some of the existing research on the interaction between MSCs and immune cells,and discuss the possible mechanisms underlying the immunomodulatory activity of MSCs in chemically-induced ALF.We conclude that MSCs can impact the phenotype and function of macrophages,as well as the differentiation and maturation of dendritic cells,and inhibit the proliferation and activation of T lymphocytes or B lymphocytes.MSCs also have immunomodulatory effects on the production of cytokines,such as prostaglandin E2 and tumor necrosis factor-alpha-stimulated gene 6,in animal models.Thus,MSCs have significant benefits in the treatment of chemically-induced ALF by interacting with immune cells and they may be applied to DILI in humans in the near future.
基金the Science and Technology Project of Jilin Provincial Department of Education[JJKH20210351KJ,JJKH20210346KJ]Jilin Province Science and Technology Development Plan Project[20200402023NC]。
文摘The embryos of maize(Zea mays L.)inbred lines GS02,GS07,GS08,GS11 and GS15 were used as receptor materials to optimize the receptor system from the aspects of genotype,medium components and stress(PEG6000,mannitol,salt and low phosphorus).The results showed that GS07 had the highest induction rate(95.2%).Orthogonal test analysis showed that the best combination of medium components in induction was A2B3C1D3(2),namely,the concentration of 2,4-dichlorophenoxy acetic acid(2,4-D)was 4 mg·mL^(-1),the concentration of L-Proline(L-Pro)was 0.8 mg·mL^(-1),and the concentration of silver nitrate(AgNO3)was 10 mg·mL^(-1)(or 5 mg·mL).Interestingly,we found that the optimal medium supplemented with 30 g·L^(-1)PEG6000 or 80 g·L^(-1)mannitol was suitable for antioxidant enzyme activity and malondialdehyde(MDA)content in GS07 callus.Exogenous 10 mmol·L^(-1)Ca^(2+)in the medium components with 100 mmol·L^(-1)sodium chloride(NaCl)could improve the activity of antioxidant enzymes in GS07 callus.Callus of GS07 could divide normally and grow well in medium components with 27 mg·L^(-1)KH_(2)PO_(4).This study enhanced the adaptability of maize callus to stress and optimized the culture conditions.
基金National Science Foundation of China(No.82002313,No.82072444)National Key Research&Development Program of China(2021YFA1101503,2018YFC2001502 and 2018YFB1105705)+2 种基金Department of Science and Technology of Hubei Province(No.2020BCB004)University Grants Committee,Research Grants Council of the Hong Kong Special Administrative Region,China(14121721,14108720,C7030-18G,T13-402/17-N and Ao E/M-402/20)Wuhan Union Hospital“Pharmaceutical Technology nursing”special fund(No.2019xhyn021)。
文摘Skeletal tissue is highly innervated.Although different types of nerves have been recently identified in the bone,the crosstalk between bone and nerves remains unclear.In this review,we outline the role of the peripheral nervous system(PNS)in bone regeneration following injury.We first introduce the conserved role of nerves in tissue regeneration in species ranging from amphibians to mammals.We then present the distribution of the PNS in the skeletal system under physiological conditions,fractures,or regeneration.Furthermore,we summarize the ways in which the PNS communicates with bone-lineage cells,the vasculature,and immune cells in the bone microenvironment.Based on this comprehensive and timely review,we conclude that the PNS regulates bone regeneration through neuropeptides or neurotransmitters and cells in the peripheral nerves.An in-depth understanding of the roles of peripheral nerves in bone regeneration will inform the development of new strategies based on bone-nerve crosstalk in promoting bone repair and regeneration.
基金sponsored by the Key Research and Development Program of Zhejiang Province (2019C03076)The funders had no role in study design,data collection and analysis,decision to publish,or preparation of the manuscript。
文摘Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has posed a serious challenge to emergency departments that usually encounter emergencies and severe diseases.[1-5]Angiotensin-converting enzyme 2(ACE2),a protein that interacts with the viral spike protein(s),allows SARS-CoV-2 to penetrate epithelial cells.[6]There is mounting evidence that suggests that the digestive system may also be affected.[7]An observational study described potential patterns of pancreatic injury(elevated amylase and lipase)in patients with coronavirus disease 2019(COVID-19).[8]Additionally,sporadic case reports have described secondary pancreatitis in patients with SARS-CoV-2 infection and presented imaging evidence.[9]Moreover,a previous study showed that COVID-19 patients not only have a higher risk of developing acute pancreatitis(AP),but also have a significantly higher mortality than those without COVID-19.[10]Using bioinformatics analysis,it may be possible to reveal how COVID-19 and AP are related.In this study,two RNA-seq datasets of SARS-CoV-2 and AP were selected for analysis.
基金supported by the Key Research and Development Program of Zhejiang Province(No.2019C03076),China。
文摘Glufosinate-ammonium herbicides are the most widely used broad-spectrum,non-selective herbicides in the world.Glufosinate-ammonium is a structural analogue of glutamate(Glu)which can irreversibly inhibit the activity of glutamine synthetase(GS)and Glu decarboxylase in plants,thereby blocking the synthesis of glutamine(Gln)from Glu and ammonia(Hoerlein,1994).This causes the plants to die because of the nitrogen metabolism disorder and subsequent intracellular accumulation of ammonia.In humans,the characteristic features of glufosinate-ammonium herbicide poisoning include gastrointestinal symptoms and neurotoxicity(Watanabe and Sano,1998).
基金sponsored by the Open Research Fund of Zhejiang First-foremost Key Subject-Acupuncture & Moxibustion,No. ZTK2010A07
文摘A rat model of middle cerebral artery permanent occlusion was established using the modified Longa method. Successfully established model animals were treated by blood-letting puncture at twelve Jing-Well points of the hand, and/or by injecting mannitol into the caudal vein twice daily. Brain tissue was collected at 24, 48 and 72 hours after modeling, and blood was collected through the retinal vein before Evans blue was injected, approximately 1 hour prior to harvesting of brain tissue. Results showed that Evans blue leakage into brain tissue and serum nitric oxide synthase activity were significantly increased in model rats. Treatment with blood-letting punctures at twelve Jing-Well points of the hand and/or injection of mannitol into the caudal vein reduced the amount of Evans blue leakage into the brain tissue and serum nitric oxide synthase activity to varying degrees. There was no significant difference between single treatment and combined treatment. Experimental findings indicate that blood-letting punctures at twelve Jing-Well points of the hand can decrease blood-brain barrier permeability and serum nitric oxide synthase activity in rats following middle cerebral artery occlusion, and its effect is similar to that of mannitol injection alone and Jing-Well points plus mannitol injection.
基金supported by Excellent Youth Team for Scientific Research,Innovation and Entre-preneurship of Dalian University(No.XQN202004)。
文摘Objective:To study the compounds isolated from Penicillium HDS-Z-1E,an endophytic fungal strain isolated from Taxus cuspidata and their activation effect of catalase(CAT).Methods:The chemical constituents were isolated from Penicillium HDS-Z-1E,by using silica gel,Sephadex LH-20 and HPLC.The structural elucidations of five metabolites were elucidated on the basis of spectroscopic including 1 H-NMR,13C-NMR,HMBC and HSQC.Their activation sites of catalase have been investigated by molecular docking.Results:Five metabolites,compounds(1–5)were isolated from Penicillium HDS-Z-1E and identified as 4-hydroxy-4-methyltetrahydro-2H-pyran-2-one(1),4-hydroxymethyl-5,6-dihydro-pyran-2-one(2),5,6-dihydro-2-oxo-2H-pyran-4-carboxylic(3),N-acetyl-hydrazinobenzoic acid(4),and methyl 2-(2,5-dihydroxyphenyl)acetate(5).Conclusion:Compound 3 is a new compound.Compounds 3 and 4 may have potential activators of catalase,providing a theoretical basis for the development of CAT activators.
基金financially supported by the National Key Research and Development Program of China (Nos. 2017YFC0212401 and 2016YFC0201505)
文摘Central Plains region of China,represented by Henan Province,is facing serious air pollution problems.Vehicular exhaust emissions had adverse impacts on the atmospheric environment.The first comprehensive and novel vehicle emission inventory for Henan Province using vehicle kilometers traveled,localized emission factors,and activity data at city-level was developed.Furthermore,3 km×3 km gridded emission and temporal variations were determined by using localized information.Results show that the total emissions of sulfur dioxide(SO2),nitrogen oxides(NOx),carbon monoxide(CO),particular matter with aerodynamic diameter<10μm(PM10),aerodynamic diameter<2.5μm(PM2.5),volatile organic compounds(VOCs),VOCs-evaporation and ammonia in 2015 were 9.1,533.4,1190.7,23.7,21.6,150.8,31.5 and 10.4 Gg,respectively,and the emission intensities of the above pollutants were 0.05,2.7,6.0,0.1,0.1,0.8,0.2 and 0.05 g/km,respectively.Vehicles meeting the Primary China 1,China 3 and China 4 contributed 89.1%,82.7%,75.3%,75.5%,75.5%,68.2%,68.4%and 82.3%for SO2,NOx,CO,PM10,PM2.5,VOCs,VOCs-evaporation and ammonia emissions,respectively.Zhengzhou,Zhoukou,Nanyang,Luoyang,Shangqiu and Xinyang showed relatively higher emissions and contributed more than 50%of each pollutant.The spatial distribution indicated obvious characteristics of the road network,and high-level emission was concentrated in the downtown areas.Additionally,the ozone formation potential(OFP)based on the estimated speciated VOC emissions was 569.6 Gg in Henan Province.Aliphatic and aromatic hydrocarbons were the main species of VOCs,whereas olefins contributed the largest proportion of OFP,with 42.2%.
基金the National Key Research and Development Program of China(No.2017YFC0212403)。
文摘In this study,we conducted an observation experiment from May 1 to June 30,2018 in Zhengzhou,a major city in central China,where ground ozone(O3)pollution has become serious in recent years.The concentrations of O3 and its precursors,as well as H2O_(2) and meteorological data were obtained from the urban site(Yanchang,YC),suburban(Zhengzhou University,ZZU)and background sites(Ganglishuiku,GLSK).Result showed that the rates of O3 concentration exceeded Chinese National Air Quality Standard GradeⅡ(93.3 ppbv)were 59.0%,52.5%,and 55.7%at the above three sites with good consistency,respectively,indicating that O3 pollution is a regional problem in Zhengzhou.The daily peak O3 appeared at 15:00-16:00,which was opposite to VOCs,NOx,and CO and consistent with H2O_(2).The exhaustive statistical analysis of meteorological factors and chemical effects on O3 formation at YC was advanced.The high concentration of precursors,high temperature,low relative humidity,and moderately high wind speed together with the wind direction dominated by south and southeast wind contribute to urban O3 episodes in Zhengzhou.O3 formation analysis showed that reactive alkenes such as isoprene and cis-2-butene contributed most to O3 formation.The VOCs/NOx ratio and smog production model were used to determine O3-VOC-NOx sensitivity.The O3 formation in Zhengzhou during early summer was mainly under VOC-limited and transition regions alternately,which implies that the simultaneous emission reduction of alkenes and NOx is effective in reducing O3 pollution in Zhengzhou.
