Background: Moxibustion is a traditional Chinese medicine(TCM) therapy in which mugwort(Artemisia vulgaris) floss is burned to warm and stimulate acupoints. The modality has been used traditionally for thousands of ye...Background: Moxibustion is a traditional Chinese medicine(TCM) therapy in which mugwort(Artemisia vulgaris) floss is burned to warm and stimulate acupoints. The modality has been used traditionally for thousands of years. However, smoke-related safety issues have recently been of concern, and little is known about moxa smoke and air quality in the clinical moxibustion environment.Objective: To assess the air quality in a typical moxibustion treatment room using particulate matter(PM) concentration and DNA oxidative damage at PM10.Methods: The study was conducted in August and November to December, 2011, at a TCM clinic in Beijing, China, in a moxibustion treatment room. A moxa-free treatment room and the outdoor area adjacent to the clinic were used as controls. PM10 concentrations were monitored with a portable digital dust indicator. The oxidative capacity of whole and water-soluble fractions of PM10 were detected using plasmid DNA assay. The results were shown as TD40 values; that is, the amount of PM10 that causes plasmid DNA damage of 40%.Results: Average PM10 concentrations in the moxibustion room were 2.56 mg m^(-3) in summer and 2.78 mg m^(-3) in winter, much higher than at control sites. For whole and water-soluble fractional PM10, the average summer TD40 values collected in the moxibustion room were 791.67 μg ml^(-1) and 876.33 μg ml^(-1) respectively, and the winter values were 779.86 μg ml^(-1) and 879.57 μg ml^(-1). These results of winter samples were significantly higher(p < 0.001) than the corresponding results from control sites. However, there was no statistical difference(p = 0.06)between the TD40 values of both the whole and water-soluble fractional PM10 from the moxibustion treatment room, while differences were significant in the general treatment room(p = 0.025) and at the outdoor site(P < 0.001).Conclusion: Our study shows that moxa smoke increases PM10 concentration. However, the oxidative capacity of PM10 in the moxibustion room was much lower than that at control sites with the same particulate burden, and the bioactivity at that site was mainly from the watersoluble fraction, another difference from the controls. This unexpected bioactivity is assumed to relate to the low toxicity of moxa smoke or to its proven antioxidant activity. Overall, further research is needed.展开更多
Background: Oxidative stress is considered to be involved in the pathophysiology of all cancers. Studies indicated that the levels of oxidative stress markers increased in breast cancer. Trace metals are essential to ...Background: Oxidative stress is considered to be involved in the pathophysiology of all cancers. Studies indicated that the levels of oxidative stress markers increased in breast cancer. Trace metals are essential to normal human homeostasis. When present in an abnormal expression, they contribute in many pathological processes. Some trace metals are claimed to be carcinogenic and capable of inducing a toxic effect through the formation of free radicles and acting as cofactors in the oxidative damage of biological macromolecules and DNA. Objective: Our aim was to investigate the serum levels of some trace elements (Copper, Zinc and Cadmium), the total oxidative and anti-oxidative capacity (TOC and TAC) in patients with breast cancer in comparison to patients with benign breast tumours. Patients and Methods: The present study included 65 females. The participates were divided into 2 main groups: control group which consisted of 20 apparently healthy female;the patient groups which divided into 3 groups: group B included 15 patients with benign breast tumours, group N consisted of 15 newly diagnosed breast cancer patients and group M included 15 patients with metastatic breast cancer. Results: The mean serum levels of Copper, Zinc, and Cadmium were significantly higher in the three patients groups (B, N and M) than the control group. Similarly, serum uric acid (UA) and (TAC) levels showed significant higher level in both breast cancer groups as compared to the benign group. However TOC levels showed only significantly higher level in metastatic group. Conclusions: The present study suggested elevated TAC, UA and TOC in breast cancer patients. The increased levels of trace elements could lead to formation of free radicals or other reactive oxygen species. The serum profile of these trace metals may be helpful in predicting prognosis of breast cancer.展开更多
It’s necessary to forecast the shortest spontaneous combustion period for preventing and controlling the coal spontaneous combustion.During the experimental process,a calculating model of the SSCP is established on t...It’s necessary to forecast the shortest spontaneous combustion period for preventing and controlling the coal spontaneous combustion.During the experimental process,a calculating model of the SSCP is established on the basis of the oxidative heat release intensity and thermal capacity at different temperatures.According to the basic parameters of spontaneous combustion,heat of water evaporation and gas desorption,the SSCPs of different coals are further predicted.Finally,this study analyzed the relationships of the SSCP and the judging indexes of the self-ignite tendency.The result shows that the SSCP non-linearly increases with the decrease of dynamic oxygen adsorption and increase of activation energy.Compared with the practical fire situation of mine,this reliable method can meet the actual requirement of mine production.展开更多
Background: The redox status of intra-uterine growth retardation(IUGR) piglets post-weaning has been poorly studied.Methods: Newborns from twenty-four sows were weighted, weaned at 21 d and fed a starter diet unti...Background: The redox status of intra-uterine growth retardation(IUGR) piglets post-weaning has been poorly studied.Methods: Newborns from twenty-four sows were weighted, weaned at 21 d and fed a starter diet until sampling.Sampling was done at 14 d post-weaning. A piglet was defined as IUGR when its birth weight was 2 SD below the mean birth weight of the total population. At weaning, eighteen piglets with nearly equal body weight from each category(i.e. IUGR or normal birth weight(NBW) piglets) were selected and then allocated to two treatments,consisted of six replicates with each pen having three piglets.Results: Compared with NBW group, IUGR significantly decreased average daily gain(P 〈 0.001), average daily feed intake(P = 0.003), and feed efficiency(P 〈 0.001) of piglets during the first two weeks post-weaning. IUGR decreased the activities of total antioxidant capacity(P = 0.019), total superoxide dismutase(T-SOD, P = 0.023),and ceruloplasmin(P = 0.044) but increased the levels of malondialdehyde(P = 0.040) and protein carbonyl(P = 0.010) in plasma. Similarly, the decreased activities of T-SOD(P = 0.005), copper- and zinc-containing superoxide dismutase(Cu/Zn-SOD, P = 0.002), and catalase(P = 0.049) was observed in the liver of IUGR piglets than these of NBW piglets. IUGR decreased hepatic Cu/Zn-SOD activity(P = 0.023) per unit of Cu/Zn-SOD protein in piglets when compared with NBW piglets. In addition, IUGR piglets exhibited the decreases in accumulation of copper in both plasma(P = 0.001) and liver(P = 0.014), as well as the concentrations of iron(P = 0.002) and zinc(P = 0.048) in liver. Compared with NBW, IUGR down-regulated m RNA expression of Cu/Zn-SOD(P = 0.021) in the liver of piglets.Conclusions: The results indicated that IUGR impaired antioxidant capacity and resulted in oxidative damage in fully weaned piglets, which might be associated with the decreased levels of redox-active trace minerals. This study highlights the importance of redox status in IUGR offspring and provides a rationale for alleviating oxidative damage by dietary interventions aiming to supplement trace minerals and to restore redox balance in the future.展开更多
Subclinical endometritis is a physiological inflammation that serves to clear persistent contaminants from the uterus. To investigate the alteration of antioxidant, such as vitamin E(VE) and vitamin C(VC), total o...Subclinical endometritis is a physiological inflammation that serves to clear persistent contaminants from the uterus. To investigate the alteration of antioxidant, such as vitamin E(VE) and vitamin C(VC), total oxidant capacity(TOC) and nitric oxide(NO) in cows with normal and subclinical endometritis(SCE), we examined the concentrations of NO, VC and VE, TOC and polymorphonuclear neutrophils(PMN) percentage in uterine secretion. The cows were divided into two groups, normal(n=20) and subclinical endometritis(SCE, n=60), based on endometrial cytology(presence of PMN≥5%). Uterine secretion and blood were collected as described previously. Griess reaction was used to determine the concentration of NO. The concentrations of TOC, VC and VE were detected by a commercially available assay kit. The results showed that the concentrations of NO, TOC and PMN percentage were significantly higher(P〈0.01, P〈0.05, and P〈0.01, respectively) in uterine secretion with SCE compared to those from normal; however, the levels of VC and VE were significantly lesser(P〈0.01). In conclusion, the concentrations of NO, TOC, VC, VE and PMN percentage differed between normal and SCE cows. Meanwhile, the relationship between the concentration of NO and PMN percentage from uterine secretion in cows with subclinical endometritis were positively correlated. Consequently, these alterations in NO, TOC, VC, VE levels and PMN percentage contributed to as a diagnostic index of the uterine inflammation, with the aim to increase the reproduction of the cows and the decrease economic losses.展开更多
Farmers are frequently exposed to ultraviolet(UV) radiation which causes various diseases by inducing oxidative stress.This study aimed to assess the effects of sunblock on oxidative stress in the body.Eighty-seven ...Farmers are frequently exposed to ultraviolet(UV) radiation which causes various diseases by inducing oxidative stress.This study aimed to assess the effects of sunblock on oxidative stress in the body.Eighty-seven farmers were divided into two groups:those who wore sunblock for five days and those who did not.The total antioxidant capacity(TAC) in urine,which is an antioxidant indicator,and 8-hydroxy-2-deoxyguanosine(8-OHdG) levels in urine,an oxidative stress indicator,were measured.The urinary TAC of sunblock users was significantly higher than that of non-users,but urinary 8-OHdG levels were not significantly different.Even after adjustment for potential confounders,urinary TAC was found to be markedly increased with sunblock usage.These results suggest that sunblock is effective in preventing oxidative stress among farmers.In addition,they show that urinary TAC can be used as a good effect marker of oxidative stress caused by UV exposure.展开更多
Atmospheric carbonyl compounds play significant roles in the cycling of radicals and have exhibited surprisingly high levels in winter that were well correlated to particulate matter,for which the reason have not been...Atmospheric carbonyl compounds play significant roles in the cycling of radicals and have exhibited surprisingly high levels in winter that were well correlated to particulate matter,for which the reason have not been clearly elucidated.Here we measured carbonyl compounds and other trace gasses together with PM_(2.5)over urban Jinan in North China Plain during the winter.Markedly higher carbonyl concentrations(average:14.63±4.21 ppbv)were found during wintertime haze pollution,about one to three-times relative to those on nonhaze days,with slight difference in chemical composition except formaldehyde(HCHO).HCHO(3.68 ppbv),acetone(3.17 ppbv),and acetaldehyde(CH_3CHO)(2.83 ppbv)were the three most abundant species,accounting for~75% of the total carbonylson both haze and non-haze days.Results from observational-based model(OBM)with atmospheric oxidation capacity(AOC)indicated that AOC significantly increased with the increasing carbonyls during the winter haze events.Carbonyl photolysis have supplied key oxidants such as RO_(2) and HO_(2),and thereby enhancing the formation of fine particles and secondary organic aerosols,elucidating the observed haze-carbonyls inter-correlation.Diurnal variation with carbonyls exhibiting peak values at early-noon and night highlighted the combined contribution of both secondary formation and primary diesel-fuel sources.1-butene was further confirmed to be the major precursor for HCHO.This study confirms the great contribution of carbonyls to AOC,and also suggests that reducing the emissions of carbonyls would be an effective way to mitigate haze pollution in urban area of the NCP region.展开更多
The pollution of atmospheric ozone in China shows an obvious upward trend in the past decade.However,the studies on the atmospheric oxidation capacity and O_(3)formation in four seasons in the southeastern coastal reg...The pollution of atmospheric ozone in China shows an obvious upward trend in the past decade.However,the studies on the atmospheric oxidation capacity and O_(3)formation in four seasons in the southeastern coastal region of China with the rapid urbanization remain limited.Here,a four-season field observation was carried out in a coastal city of southeast China,using an observation-based model combining with the Master Chemical Mechanism,to explore the atmospheric oxidation capacity(AOC),radical chemistry,O_(3)formation pathways and sensitivity.The results showed that the average net O_(3)production rate(14.55 ppbv/hr)in summer was the strongest,but the average O_(3)concentrations in autumn was higher.The AOC and ROx levels presented an obvious seasonal pattern with the maximum value in summer,while the OH reactivity in winter was the highest with an average value of 22.75 sec^(-1).The OH reactivity was dominated by oxygenated VOCs(OVOCs)(30.6%-42.8%),CO(23.2%-26.8%),NO_(2)(13.6%-22.0%),and alkenes(8.4%-12.5%)in different seasons.HONO photolysis dominated OH primary source on daytime in winter,while in other seasons,HONO photolysis in the morning and ozone photolysis in the afternoon contributed mostly.Sensitivity analysis indicated that O_(3)production was controlled by VOCs in spring,autumn and winter,but a VOC-limited and NOx-limited regime in summer,and alkene and aromatic species were the major controlling factors to O_(3)formation.Overall,the study characterized the atmospheric oxidation capacity and elucidated the controlling factors for O_(3)production in the coastal area with the rapid urbanization in China.展开更多
A new indicator with temperature dependence of the NO3 loss frequency, was developed to study the contribution of NO3 to the oxidation of monoterpenes and NOx removal in the atmosphere. The new indicator arises from t...A new indicator with temperature dependence of the NO3 loss frequency, was developed to study the contribution of NO3 to the oxidation of monoterpenes and NOx removal in the atmosphere. The new indicator arises from the temperature dependence of kinetic constant. The new indicator was applied to data of observation based on differential optical absorption spectroscopy system on the outskirts of Hefei, China. According to the findings, the contribution of monoterpenes to the loss of NO3 was 70%-80%.展开更多
Electric discharge in water can generate a large number of oxidants such as ozone, hydrogen peroxide and hydroxyl radicals. In this paper, a non-thermal plasma processing system was established by means of pulsed diel...Electric discharge in water can generate a large number of oxidants such as ozone, hydrogen peroxide and hydroxyl radicals. In this paper, a non-thermal plasma processing system was established by means of pulsed dielectric barrier discharge in gas-liquid phase. The electrodes of discharge reactor were staggered. The yield of H2O2 was enhanced after discharge. The effects of discharge time, discharge voltage, frequency, initial pH value, and feed gas were investigated. The concentration of hydrogen peroxide and ozone was measured after discharge. The experimental results were fully analyzed. The chemical reaction equations in water were given as much as possible. At last, the water containing Rhodamine B was tested in this system. The degradation rate came to 94.22% in 30 min.展开更多
It is shown by the the law of mass action in combination with the coexistence theory of slag structure that KMn n =NMno /(NFeo [%Mn] does not change with basicities and maintains constant at constant temperature; the...It is shown by the the law of mass action in combination with the coexistence theory of slag structure that KMn n =NMno /(NFeo [%Mn] does not change with basicities and maintains constant at constant temperature; the oxidizing capabilities of multicomponent slag systems containing CaO, MgO etc., can be expressed by NFe tO =NFeO + 6NFe2 O3 + 8NFe3O4; the desulfurizing capabilities of various basic oxides for multicomponent slag systems can be calculated by Ls=8(KCaSNCaO+KMgsNMgo +KFeSNFeO)∑n/[%O]; the dephosphorizing capabili- ties of CaO-MgO-FeO-FeO O3-P2 O5 as well as CaO-FeO-Fe2 O3-A12 O3-P2 O5 molten slags expressed respectively by Lpo=(%P2O5)/[P]2 = 141.94[%O]5∑nK00(1 + K5N2Cao + K6N3CaO + K7N4CaO + K8N2MgO + K9N3MgO + K10N3FeO + K11N4Feo); LPO=(%P2O5)/[P]2= 141.94[%O]5∑nK00(1 + K10N2CaO+ K11N3CaO+ K12N4CaO + K13N3FeO + K14N4FeO) have good agreement with practical values.展开更多
Atmospheric oxidizing capacity(AOC)is the fundamental driving factors of chemistry process(e.g.,the formation of ozone(O_(3))and secondary organic aerosols(SOA))in the troposphere.However,accurate quantification of AO...Atmospheric oxidizing capacity(AOC)is the fundamental driving factors of chemistry process(e.g.,the formation of ozone(O_(3))and secondary organic aerosols(SOA))in the troposphere.However,accurate quantification of AOC still remains uncertainty.In this study,a comprehensive field campaign was conducted during autumn 2019 in downtown of Beijing,where O_(3) and PM_(2.5) episodes had been experienced successively.The observation-based model(OBM)is used to quantify the AOC at O_(3) and PM_(2.5) episodes.The strong intensity of AOC is found at O_(3) and PM2.5 episodes,and hydroxyl radical(OH)is the dominating daytime oxidant for both episodes.The photolysis of O_(3) is main source of OH at O_(3) episode;the photolysis of nitrous acid(HONO)and formaldehyde(HCHO)plays important role in OH formation at PM_(2.5) episode.The radicals loss routines vary according to precursor pollutants,resulting in different types of air pollution.O_(3) budgets and sensitivity analysis indicates that O_(3) production is transition regime(both VOC and NOx-limited)at O3 episode.The heterogeneous reaction of hydroperoxy radicals(HO_(2))on aerosol surfaces has significant influence on OH and O_(3) production rates.The HO_(2) uptake coefficient(γHO_(2))is the determining factor and required accurate measurement in real atmospheric environment.Our findings could provide the important bases for coordinated control of PM_(2.5) and O_(3) pollution.展开更多
The exchanges of NOx between snow and air have significant impact on the atmospheric components and photochemical processes in the overlying boundary layer. Such exchanges increase the oxidizing capacity of the atmosp...The exchanges of NOx between snow and air have significant impact on the atmospheric components and photochemical processes in the overlying boundary layer. Such exchanges increase the oxidizing capacity of the atmosphere and may have a crucial impact on the air signals that are retrieved from ice cores. In the recent years, sunlit snow and ice have been demonstrated to be important NOx sources in the polar atmospheric boundary layer. This paper makes a thorough review on the release of NOx from snow and ice, including field observations and experimental evidences, release mechanisms and influential parameters that affect such a release process, polar NOx concentrations and fluxes, and environmental impacts of the chemical processes of NOx in the polar atmospheric boundary layer. In the Tibetan Plateau, the released NOx observed recently in the sunlit snow/ice-cover is 1-order magnitude more than that in polar regions, but further scientific research is still needed to reveal its impact on the atmospheric oxidizing capacity.展开更多
Atmospheric oxidation processes are of central importance in atmospheric climate models.It is often considered that volatile organic molecules are mainly removed by hydroxyl radical;however,the kinetics of some reacti...Atmospheric oxidation processes are of central importance in atmospheric climate models.It is often considered that volatile organic molecules are mainly removed by hydroxyl radical;however,the kinetics of some reactions of hydroxyl radical with volatile organic molecules are slow.Here we report rate constants for rapid reactions of formyl fluoride with Criegee intermediates.These rate constants are calculated by dual-level multistructural canonical variational transition state theory with small-curvature tunneling(DL-MS-CVT/SCT).The treatment contains beyond-CCSD(T)electronic structure calculations for transition state theory,and it employs validated density functional input for multistructural canonical variational transition state theory with small-curvature tunneling and for variable-reaction-coordinate variational transition state theory.We find that the M11-L density functional has higher accuracy than CCSD(T)/CBS for the HC(O)F+CH2OO and HC(O)F+anti-CH_(3)CHOO reactions.We find significant negative temperature dependence in the ratios of the rate constants for HC(O)F+CH2OO/anti-CH_(3)CHOO to the rate constant for HC(O)F+OH.We also find that different Criegee intermediates have different rate-determining-steps in their reactions with formyl fluoride,and we find that the dominant gas-phase removal mechanism for HC(O)F in the atmosphere is the reaction with CH2OO and/or anti-CH_(3)CHOO Criegee intermediates.展开更多
To investigate the sensitivity of secondary aerosol formation and oxidation capacity to NOx in homogeneous and heterogeneous reactions, a series of irradiated toluene/NOx/air and ?-pinene/NOx/air experiments were cond...To investigate the sensitivity of secondary aerosol formation and oxidation capacity to NOx in homogeneous and heterogeneous reactions, a series of irradiated toluene/NOx/air and ?-pinene/NOx/air experiments were conducted in smog chambers in the absence or presence of Al2O3 seed particles. Various concentrations of NOx and volatile organic compounds(VOCs) were designed to simulate secondary aerosol formation under different scenarios for NOx. Under "VOC-limited" conditions, the increasing NOx concentration suppressed secondary aerosol formation, while the increasing toluene concentration not only contributed to the increase in secondary aerosol formation, but also led to the elevated oxidation degree for the organic aerosol. Sulfate formation was suppressed with the increasing NOx due to a decreased oxidation capacity of the photooxidation system. Secondary organic aerosol(SOA) formation also decreased with the presence of high concentration of NOx, because organo-peroxy radicals(RO2) react with NOx instead of with peroxy radicals(RO2 or HO2), resulting in the formation of volatile organic products. The increasing concentration of NOx enhanced the formation of sulfate, nitrate and SOA under "NOx-limited" conditions, in which the heterogeneous reactions played an important role. In the presence of Al2O3 seed particles, a synergetic promoting effect of mineral dust and NOx on secondary aerosol formation in heterogeneous reactions was observed in the photooxidation. This synergetic effect strengthened the positive relationship between NOx and secondary aerosol formation under "NOx-limited" conditions but weakened or even overturned the negative relationship between NOx and secondary aerosol formation under "VOC-limited" conditions. Sensitivity of secondary aerosol formation to NOx seemed different in homogeneous and heterogeneous reactions, and should be both taken into account in the sensitivity study. The sensitivity of secondary aerosol formation to NOx was further investigated under "winter-like" and NH3-rich conditions. No obvious difference for the sensitivity of secondary aerosol formation except nitrate to NOx was observed.展开更多
Organic aerosol(OA)is a major component of atmospheric particulate matter(PM)with complex composition and formation processes influenced by various factors.Emission reduction can alter both precursors and oxidants whi...Organic aerosol(OA)is a major component of atmospheric particulate matter(PM)with complex composition and formation processes influenced by various factors.Emission reduction can alter both precursors and oxidants which further affects secondary OA formation.Here we provide an observational analysis of secondary OA(SOA)variation properties in Yangtze River Delta(YRD)of eastern China in response to large scale of emission reduction during Chinese New Year(CNY)holidays from 2015 to 2020,and the COVID-19 pandemic period from January to March,2020.We found a 17%increase of SOA proportion during the COVID lockdown.The relative enrichment of SOA is also found during multi-year CNY holidays with dramatic reduction of anthropogenic emissions.Two types of oxygenated OA(OOA)influenced by mixed emissions and SOA formation were found to be the dominant components during the lockdown in YRD region.Our results highlight that these emission-reduction-induced changes in organic aerosol need to be considered in the future to optimize air pollution control measures.展开更多
Atmospheric oxidizing capacity(AOC)is an essential driving force of troposphere chemistry and self-cleaning,but the definition of AOC and its quantitative representation remain uncertain.Driven by national demand for ...Atmospheric oxidizing capacity(AOC)is an essential driving force of troposphere chemistry and self-cleaning,but the definition of AOC and its quantitative representation remain uncertain.Driven by national demand for air pollution control in recent years,Chinese scholars have carried out studies on theories of atmospheric chemistry and have made considerable progress in AOC research.This paper will give a brief review of these developments.First,AOC indexes were established that represent apparent atmospheric oxidizing ability(AOIe)and potential atmospheric oxidizing ability(AOIp)based on aspects of macrothermodynamics and microdynamics,respectively.A closed study refined the quantitative contributions of heterogeneous chemistry to AOC in Beijing,and these AOC methods were further applied in Beijing-Tianjin-Hebei and key areas across the country.In addition,the detection of ground or vertical profiles for atmospheric OH·,HO_(2)·,NO_(3)·radicals and reservoir molecules can now be obtained with domestic instruments in diverse environments.Moreover,laboratory smoke chamber simulations revealed heterogeneous processes involving reactions of O_(3)and NO_(2),which are typical oxidants in the surface/interface atmosphere,and the evolutionary and budgetary implications of atmospheric oxidants reacting under multispecies,multiphase and multi-interface conditions were obtained.Finally,based on the GRAPES-CUACE adjoint model improved by Chinese scholars,simulations of key substances affecting atmospheric oxidation and secondary organic and inorganic aerosol formation have been optimized.Normalized numerical simulations of AOIe and AOIp were performed,and regional coordination of AOC was adjusted.An optimized plan for controlling O_(3)and PM2.5was analyzed by scenario simulation.展开更多
Ratiometric probes facilitate quantitative studies via self-calibration and are cherished for bioimaging.Often,a small probe-product spectral separation leads to crosstalk,but the rational development of ratiometric p...Ratiometric probes facilitate quantitative studies via self-calibration and are cherished for bioimaging.Often,a small probe-product spectral separation leads to crosstalk,but the rational development of ratiometric probes with zero probe-product crosstalk remains challenging.Harnessing the recent progress on photophysical modulation of xanthenoid fluorochromes,we propose a powerful and versatile probe design principle,that is,“bridging-group modification,”and developed totalROX,a robust probe for monitoring the total cellular oxidative capacity.展开更多
Urban and regional air pollutions are characterized by high concentrations of secondary pollutants such as photo-oxidants (mainly ozone) and fine particulate matter, which are formed through chemical reactions of th...Urban and regional air pollutions are characterized by high concentrations of secondary pollutants such as photo-oxidants (mainly ozone) and fine particulate matter, which are formed through chemical reactions of the primary pollutants emitted from various sources. The accumulation of these pollutants under stagnant meteorological conditions results in the formation of gray haze, reducing visibility and causing major impacts on human health and climate. In an air pollution complex, the co- existence of high concentrations of primary and secondary gaseous and particulate pollutants provides a large amount of reac- tants for heterogeneous reactions on the surface of fine particles; these reactions change the oxidizing capacity of the atmos- phere, as well as chemical compositions along with the physicochemical and optical properties of particulate matter, thereby accelerating formation of the air pollution complex and gray haze. Using in situ technologies, such as diffuse reflectance infra- red Fourier-transform spectroscopy and single-particle Raman spectroscopy, we systematically investigated the reaction kinet- ics and mechanisms of gaseous pollutants (i.e., NO2, SO2, 03, and formaldehyde) on the surfaces of the major components of atmospheric particles such as CaCO3, kaolinite, montmorillonite, NaC1, sea salt, A1203, and Tit2. We found that the main re- action products were sulfate, nitrate, or formate, which can change the hygroscopicity and light extinction parameters of those particles significantly. By analyzing the reaction kinetics of these heterogeneous reactions, we identified synergetic mechanisms of the three ternary reaction systems, ,i.e., NOE-particles-H2O, SO2-particles-O3, and organics/SO2-particles-UV illumination. These synergetic mechanisms can provide experimental and theoretical bases for understanding the feedback mechanisms and nonlinear processes in the formation of an air pollution complex and gray haze.展开更多
基金supported by the National Basic Research Program of China(973 Program NO.2009CB522906)National Natural Science Foundation of China(NO.81072862)
文摘Background: Moxibustion is a traditional Chinese medicine(TCM) therapy in which mugwort(Artemisia vulgaris) floss is burned to warm and stimulate acupoints. The modality has been used traditionally for thousands of years. However, smoke-related safety issues have recently been of concern, and little is known about moxa smoke and air quality in the clinical moxibustion environment.Objective: To assess the air quality in a typical moxibustion treatment room using particulate matter(PM) concentration and DNA oxidative damage at PM10.Methods: The study was conducted in August and November to December, 2011, at a TCM clinic in Beijing, China, in a moxibustion treatment room. A moxa-free treatment room and the outdoor area adjacent to the clinic were used as controls. PM10 concentrations were monitored with a portable digital dust indicator. The oxidative capacity of whole and water-soluble fractions of PM10 were detected using plasmid DNA assay. The results were shown as TD40 values; that is, the amount of PM10 that causes plasmid DNA damage of 40%.Results: Average PM10 concentrations in the moxibustion room were 2.56 mg m^(-3) in summer and 2.78 mg m^(-3) in winter, much higher than at control sites. For whole and water-soluble fractional PM10, the average summer TD40 values collected in the moxibustion room were 791.67 μg ml^(-1) and 876.33 μg ml^(-1) respectively, and the winter values were 779.86 μg ml^(-1) and 879.57 μg ml^(-1). These results of winter samples were significantly higher(p < 0.001) than the corresponding results from control sites. However, there was no statistical difference(p = 0.06)between the TD40 values of both the whole and water-soluble fractional PM10 from the moxibustion treatment room, while differences were significant in the general treatment room(p = 0.025) and at the outdoor site(P < 0.001).Conclusion: Our study shows that moxa smoke increases PM10 concentration. However, the oxidative capacity of PM10 in the moxibustion room was much lower than that at control sites with the same particulate burden, and the bioactivity at that site was mainly from the watersoluble fraction, another difference from the controls. This unexpected bioactivity is assumed to relate to the low toxicity of moxa smoke or to its proven antioxidant activity. Overall, further research is needed.
文摘Background: Oxidative stress is considered to be involved in the pathophysiology of all cancers. Studies indicated that the levels of oxidative stress markers increased in breast cancer. Trace metals are essential to normal human homeostasis. When present in an abnormal expression, they contribute in many pathological processes. Some trace metals are claimed to be carcinogenic and capable of inducing a toxic effect through the formation of free radicles and acting as cofactors in the oxidative damage of biological macromolecules and DNA. Objective: Our aim was to investigate the serum levels of some trace elements (Copper, Zinc and Cadmium), the total oxidative and anti-oxidative capacity (TOC and TAC) in patients with breast cancer in comparison to patients with benign breast tumours. Patients and Methods: The present study included 65 females. The participates were divided into 2 main groups: control group which consisted of 20 apparently healthy female;the patient groups which divided into 3 groups: group B included 15 patients with benign breast tumours, group N consisted of 15 newly diagnosed breast cancer patients and group M included 15 patients with metastatic breast cancer. Results: The mean serum levels of Copper, Zinc, and Cadmium were significantly higher in the three patients groups (B, N and M) than the control group. Similarly, serum uric acid (UA) and (TAC) levels showed significant higher level in both breast cancer groups as compared to the benign group. However TOC levels showed only significantly higher level in metastatic group. Conclusions: The present study suggested elevated TAC, UA and TOC in breast cancer patients. The increased levels of trace elements could lead to formation of free radicals or other reactive oxygen species. The serum profile of these trace metals may be helpful in predicting prognosis of breast cancer.
基金supported by China National Science Foundation of China (Nos.51074158 and 51304189)the Youth Science and Research Fund of China University of Mining and Technology of China (No.2009A006)
文摘It’s necessary to forecast the shortest spontaneous combustion period for preventing and controlling the coal spontaneous combustion.During the experimental process,a calculating model of the SSCP is established on the basis of the oxidative heat release intensity and thermal capacity at different temperatures.According to the basic parameters of spontaneous combustion,heat of water evaporation and gas desorption,the SSCPs of different coals are further predicted.Finally,this study analyzed the relationships of the SSCP and the judging indexes of the self-ignite tendency.The result shows that the SSCP non-linearly increases with the decrease of dynamic oxygen adsorption and increase of activation energy.Compared with the practical fire situation of mine,this reliable method can meet the actual requirement of mine production.
基金supported by the National Natural Science Foundation of China (31272454)
文摘Background: The redox status of intra-uterine growth retardation(IUGR) piglets post-weaning has been poorly studied.Methods: Newborns from twenty-four sows were weighted, weaned at 21 d and fed a starter diet until sampling.Sampling was done at 14 d post-weaning. A piglet was defined as IUGR when its birth weight was 2 SD below the mean birth weight of the total population. At weaning, eighteen piglets with nearly equal body weight from each category(i.e. IUGR or normal birth weight(NBW) piglets) were selected and then allocated to two treatments,consisted of six replicates with each pen having three piglets.Results: Compared with NBW group, IUGR significantly decreased average daily gain(P 〈 0.001), average daily feed intake(P = 0.003), and feed efficiency(P 〈 0.001) of piglets during the first two weeks post-weaning. IUGR decreased the activities of total antioxidant capacity(P = 0.019), total superoxide dismutase(T-SOD, P = 0.023),and ceruloplasmin(P = 0.044) but increased the levels of malondialdehyde(P = 0.040) and protein carbonyl(P = 0.010) in plasma. Similarly, the decreased activities of T-SOD(P = 0.005), copper- and zinc-containing superoxide dismutase(Cu/Zn-SOD, P = 0.002), and catalase(P = 0.049) was observed in the liver of IUGR piglets than these of NBW piglets. IUGR decreased hepatic Cu/Zn-SOD activity(P = 0.023) per unit of Cu/Zn-SOD protein in piglets when compared with NBW piglets. In addition, IUGR piglets exhibited the decreases in accumulation of copper in both plasma(P = 0.001) and liver(P = 0.014), as well as the concentrations of iron(P = 0.002) and zinc(P = 0.048) in liver. Compared with NBW, IUGR down-regulated m RNA expression of Cu/Zn-SOD(P = 0.021) in the liver of piglets.Conclusions: The results indicated that IUGR impaired antioxidant capacity and resulted in oxidative damage in fully weaned piglets, which might be associated with the decreased levels of redox-active trace minerals. This study highlights the importance of redox status in IUGR offspring and provides a rationale for alleviating oxidative damage by dietary interventions aiming to supplement trace minerals and to restore redox balance in the future.
基金Supported by Funding(RCB22)from the Doctoral Research Foundation of Northeast Agricultural University(2012)the Postdoctoral Fund of Heilongjiang Province(LBH-Z11239)
文摘Subclinical endometritis is a physiological inflammation that serves to clear persistent contaminants from the uterus. To investigate the alteration of antioxidant, such as vitamin E(VE) and vitamin C(VC), total oxidant capacity(TOC) and nitric oxide(NO) in cows with normal and subclinical endometritis(SCE), we examined the concentrations of NO, VC and VE, TOC and polymorphonuclear neutrophils(PMN) percentage in uterine secretion. The cows were divided into two groups, normal(n=20) and subclinical endometritis(SCE, n=60), based on endometrial cytology(presence of PMN≥5%). Uterine secretion and blood were collected as described previously. Griess reaction was used to determine the concentration of NO. The concentrations of TOC, VC and VE were detected by a commercially available assay kit. The results showed that the concentrations of NO, TOC and PMN percentage were significantly higher(P〈0.01, P〈0.05, and P〈0.01, respectively) in uterine secretion with SCE compared to those from normal; however, the levels of VC and VE were significantly lesser(P〈0.01). In conclusion, the concentrations of NO, TOC, VC, VE and PMN percentage differed between normal and SCE cows. Meanwhile, the relationship between the concentration of NO and PMN percentage from uterine secretion in cows with subclinical endometritis were positively correlated. Consequently, these alterations in NO, TOC, VC, VE levels and PMN percentage contributed to as a diagnostic index of the uterine inflammation, with the aim to increase the reproduction of the cows and the decrease economic losses.
基金supported by Ministry of Agriculture,Food and Rural Affairs,Republic of Korea
文摘Farmers are frequently exposed to ultraviolet(UV) radiation which causes various diseases by inducing oxidative stress.This study aimed to assess the effects of sunblock on oxidative stress in the body.Eighty-seven farmers were divided into two groups:those who wore sunblock for five days and those who did not.The total antioxidant capacity(TAC) in urine,which is an antioxidant indicator,and 8-hydroxy-2-deoxyguanosine(8-OHdG) levels in urine,an oxidative stress indicator,were measured.The urinary TAC of sunblock users was significantly higher than that of non-users,but urinary 8-OHdG levels were not significantly different.Even after adjustment for potential confounders,urinary TAC was found to be markedly increased with sunblock usage.These results suggest that sunblock is effective in preventing oxidative stress among farmers.In addition,they show that urinary TAC can be used as a good effect marker of oxidative stress caused by UV exposure.
基金supported by the National Natural Science Foundation of China(Nos.42005092,42275127,42075112and 41775127)the Natural Science Foundation of Shandong Province(No.ZR2020QD058)。
文摘Atmospheric carbonyl compounds play significant roles in the cycling of radicals and have exhibited surprisingly high levels in winter that were well correlated to particulate matter,for which the reason have not been clearly elucidated.Here we measured carbonyl compounds and other trace gasses together with PM_(2.5)over urban Jinan in North China Plain during the winter.Markedly higher carbonyl concentrations(average:14.63±4.21 ppbv)were found during wintertime haze pollution,about one to three-times relative to those on nonhaze days,with slight difference in chemical composition except formaldehyde(HCHO).HCHO(3.68 ppbv),acetone(3.17 ppbv),and acetaldehyde(CH_3CHO)(2.83 ppbv)were the three most abundant species,accounting for~75% of the total carbonylson both haze and non-haze days.Results from observational-based model(OBM)with atmospheric oxidation capacity(AOC)indicated that AOC significantly increased with the increasing carbonyls during the winter haze events.Carbonyl photolysis have supplied key oxidants such as RO_(2) and HO_(2),and thereby enhancing the formation of fine particles and secondary organic aerosols,elucidating the observed haze-carbonyls inter-correlation.Diurnal variation with carbonyls exhibiting peak values at early-noon and night highlighted the combined contribution of both secondary formation and primary diesel-fuel sources.1-butene was further confirmed to be the major precursor for HCHO.This study confirms the great contribution of carbonyls to AOC,and also suggests that reducing the emissions of carbonyls would be an effective way to mitigate haze pollution in urban area of the NCP region.
基金funded by the Cultivating Project of Strategic Priority Research Program of Chinese Academy of Sciences (No.XDPB1903)the Science and Technology Department of Fujian Province (No.2022L3025)+1 种基金the National Natural Science Foundation of China (No.U22A20578&42277091)the Center for Excellence in Regional Atmospheric Environment Project (No.E0L1B20201)。
文摘The pollution of atmospheric ozone in China shows an obvious upward trend in the past decade.However,the studies on the atmospheric oxidation capacity and O_(3)formation in four seasons in the southeastern coastal region of China with the rapid urbanization remain limited.Here,a four-season field observation was carried out in a coastal city of southeast China,using an observation-based model combining with the Master Chemical Mechanism,to explore the atmospheric oxidation capacity(AOC),radical chemistry,O_(3)formation pathways and sensitivity.The results showed that the average net O_(3)production rate(14.55 ppbv/hr)in summer was the strongest,but the average O_(3)concentrations in autumn was higher.The AOC and ROx levels presented an obvious seasonal pattern with the maximum value in summer,while the OH reactivity in winter was the highest with an average value of 22.75 sec^(-1).The OH reactivity was dominated by oxygenated VOCs(OVOCs)(30.6%-42.8%),CO(23.2%-26.8%),NO_(2)(13.6%-22.0%),and alkenes(8.4%-12.5%)in different seasons.HONO photolysis dominated OH primary source on daytime in winter,while in other seasons,HONO photolysis in the morning and ozone photolysis in the afternoon contributed mostly.Sensitivity analysis indicated that O_(3)production was controlled by VOCs in spring,autumn and winter,but a VOC-limited and NOx-limited regime in summer,and alkene and aromatic species were the major controlling factors to O_(3)formation.Overall,the study characterized the atmospheric oxidation capacity and elucidated the controlling factors for O_(3)production in the coastal area with the rapid urbanization in China.
基金ACKNOWLEDGMENTS We acknowledged to DOAS groups. This work was supported by the Key Project of Chinese Ministry of Education (No.209057), the Anhui Provincial Natural Science Foundation (No.090412028), and the Natural Science Foundation of Anhui Province Colleges and University (No.KJ2008A114).
文摘A new indicator with temperature dependence of the NO3 loss frequency, was developed to study the contribution of NO3 to the oxidation of monoterpenes and NOx removal in the atmosphere. The new indicator arises from the temperature dependence of kinetic constant. The new indicator was applied to data of observation based on differential optical absorption spectroscopy system on the outskirts of Hefei, China. According to the findings, the contribution of monoterpenes to the loss of NO3 was 70%-80%.
基金supported by National Natural Science Foundation of China(No.11075041)
文摘Electric discharge in water can generate a large number of oxidants such as ozone, hydrogen peroxide and hydroxyl radicals. In this paper, a non-thermal plasma processing system was established by means of pulsed dielectric barrier discharge in gas-liquid phase. The electrodes of discharge reactor were staggered. The yield of H2O2 was enhanced after discharge. The effects of discharge time, discharge voltage, frequency, initial pH value, and feed gas were investigated. The concentration of hydrogen peroxide and ozone was measured after discharge. The experimental results were fully analyzed. The chemical reaction equations in water were given as much as possible. At last, the water containing Rhodamine B was tested in this system. The degradation rate came to 94.22% in 30 min.
文摘It is shown by the the law of mass action in combination with the coexistence theory of slag structure that KMn n =NMno /(NFeo [%Mn] does not change with basicities and maintains constant at constant temperature; the oxidizing capabilities of multicomponent slag systems containing CaO, MgO etc., can be expressed by NFe tO =NFeO + 6NFe2 O3 + 8NFe3O4; the desulfurizing capabilities of various basic oxides for multicomponent slag systems can be calculated by Ls=8(KCaSNCaO+KMgsNMgo +KFeSNFeO)∑n/[%O]; the dephosphorizing capabili- ties of CaO-MgO-FeO-FeO O3-P2 O5 as well as CaO-FeO-Fe2 O3-A12 O3-P2 O5 molten slags expressed respectively by Lpo=(%P2O5)/[P]2 = 141.94[%O]5∑nK00(1 + K5N2Cao + K6N3CaO + K7N4CaO + K8N2MgO + K9N3MgO + K10N3FeO + K11N4Feo); LPO=(%P2O5)/[P]2= 141.94[%O]5∑nK00(1 + K10N2CaO+ K11N3CaO+ K12N4CaO + K13N3FeO + K14N4FeO) have good agreement with practical values.
基金supported by the National Key Research and Development Program of China (No. 2017YFC0210001)the National Natural Science Foundation of China (Nos. 41830106, 42022039)+1 种基金Beijing National Laboratory for Molecular Sciences (No. BNLMS-CXXM-202011)the Youth Innovation Promotion Association CAS (No. 2017042)
文摘Atmospheric oxidizing capacity(AOC)is the fundamental driving factors of chemistry process(e.g.,the formation of ozone(O_(3))and secondary organic aerosols(SOA))in the troposphere.However,accurate quantification of AOC still remains uncertainty.In this study,a comprehensive field campaign was conducted during autumn 2019 in downtown of Beijing,where O_(3) and PM_(2.5) episodes had been experienced successively.The observation-based model(OBM)is used to quantify the AOC at O_(3) and PM_(2.5) episodes.The strong intensity of AOC is found at O_(3) and PM2.5 episodes,and hydroxyl radical(OH)is the dominating daytime oxidant for both episodes.The photolysis of O_(3) is main source of OH at O_(3) episode;the photolysis of nitrous acid(HONO)and formaldehyde(HCHO)plays important role in OH formation at PM_(2.5) episode.The radicals loss routines vary according to precursor pollutants,resulting in different types of air pollution.O_(3) budgets and sensitivity analysis indicates that O_(3) production is transition regime(both VOC and NOx-limited)at O3 episode.The heterogeneous reaction of hydroperoxy radicals(HO_(2))on aerosol surfaces has significant influence on OH and O_(3) production rates.The HO_(2) uptake coefficient(γHO_(2))is the determining factor and required accurate measurement in real atmospheric environment.Our findings could provide the important bases for coordinated control of PM_(2.5) and O_(3) pollution.
基金supported by the Fund of Polar Scientific Research(No.20080216) of State Ocean Administration, Chinaby Chinese Natural Science Foundation(No. 20407001,No.40701170)
文摘The exchanges of NOx between snow and air have significant impact on the atmospheric components and photochemical processes in the overlying boundary layer. Such exchanges increase the oxidizing capacity of the atmosphere and may have a crucial impact on the air signals that are retrieved from ice cores. In the recent years, sunlit snow and ice have been demonstrated to be important NOx sources in the polar atmospheric boundary layer. This paper makes a thorough review on the release of NOx from snow and ice, including field observations and experimental evidences, release mechanisms and influential parameters that affect such a release process, polar NOx concentrations and fluxes, and environmental impacts of the chemical processes of NOx in the polar atmospheric boundary layer. In the Tibetan Plateau, the released NOx observed recently in the sunlit snow/ice-cover is 1-order magnitude more than that in polar regions, but further scientific research is still needed to reveal its impact on the atmospheric oxidizing capacity.
基金supported in part by the National Natural Science Foundation of China(42120104007 and 41775125)by Guizhou Provincial Science and Technology Projects,China(CXTD[2022]001 and GCC[2023]026)+1 种基金by the Science and Technology Foundation of Guizhou Provincial Department of Education,China(KY[2021]014 and KY[2021]107)supported in part by the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences under Award DE-SC0015997.
文摘Atmospheric oxidation processes are of central importance in atmospheric climate models.It is often considered that volatile organic molecules are mainly removed by hydroxyl radical;however,the kinetics of some reactions of hydroxyl radical with volatile organic molecules are slow.Here we report rate constants for rapid reactions of formyl fluoride with Criegee intermediates.These rate constants are calculated by dual-level multistructural canonical variational transition state theory with small-curvature tunneling(DL-MS-CVT/SCT).The treatment contains beyond-CCSD(T)electronic structure calculations for transition state theory,and it employs validated density functional input for multistructural canonical variational transition state theory with small-curvature tunneling and for variable-reaction-coordinate variational transition state theory.We find that the M11-L density functional has higher accuracy than CCSD(T)/CBS for the HC(O)F+CH2OO and HC(O)F+anti-CH_(3)CHOO reactions.We find significant negative temperature dependence in the ratios of the rate constants for HC(O)F+CH2OO/anti-CH_(3)CHOO to the rate constant for HC(O)F+OH.We also find that different Criegee intermediates have different rate-determining-steps in their reactions with formyl fluoride,and we find that the dominant gas-phase removal mechanism for HC(O)F in the atmosphere is the reaction with CH2OO and/or anti-CH_(3)CHOO Criegee intermediates.
基金supported by the National Natural Science Foundation of China(21407158)the"Strategic Priority Research Program"of the Chinese Academy of Sciences(XDB05010300,XDB05040100,XDB05010200)
文摘To investigate the sensitivity of secondary aerosol formation and oxidation capacity to NOx in homogeneous and heterogeneous reactions, a series of irradiated toluene/NOx/air and ?-pinene/NOx/air experiments were conducted in smog chambers in the absence or presence of Al2O3 seed particles. Various concentrations of NOx and volatile organic compounds(VOCs) were designed to simulate secondary aerosol formation under different scenarios for NOx. Under "VOC-limited" conditions, the increasing NOx concentration suppressed secondary aerosol formation, while the increasing toluene concentration not only contributed to the increase in secondary aerosol formation, but also led to the elevated oxidation degree for the organic aerosol. Sulfate formation was suppressed with the increasing NOx due to a decreased oxidation capacity of the photooxidation system. Secondary organic aerosol(SOA) formation also decreased with the presence of high concentration of NOx, because organo-peroxy radicals(RO2) react with NOx instead of with peroxy radicals(RO2 or HO2), resulting in the formation of volatile organic products. The increasing concentration of NOx enhanced the formation of sulfate, nitrate and SOA under "NOx-limited" conditions, in which the heterogeneous reactions played an important role. In the presence of Al2O3 seed particles, a synergetic promoting effect of mineral dust and NOx on secondary aerosol formation in heterogeneous reactions was observed in the photooxidation. This synergetic effect strengthened the positive relationship between NOx and secondary aerosol formation under "NOx-limited" conditions but weakened or even overturned the negative relationship between NOx and secondary aerosol formation under "VOC-limited" conditions. Sensitivity of secondary aerosol formation to NOx seemed different in homogeneous and heterogeneous reactions, and should be both taken into account in the sensitivity study. The sensitivity of secondary aerosol formation to NOx was further investigated under "winter-like" and NH3-rich conditions. No obvious difference for the sensitivity of secondary aerosol formation except nitrate to NOx was observed.
基金supported by National Natural Science Foundation of China(No.42005082).
文摘Organic aerosol(OA)is a major component of atmospheric particulate matter(PM)with complex composition and formation processes influenced by various factors.Emission reduction can alter both precursors and oxidants which further affects secondary OA formation.Here we provide an observational analysis of secondary OA(SOA)variation properties in Yangtze River Delta(YRD)of eastern China in response to large scale of emission reduction during Chinese New Year(CNY)holidays from 2015 to 2020,and the COVID-19 pandemic period from January to March,2020.We found a 17%increase of SOA proportion during the COVID lockdown.The relative enrichment of SOA is also found during multi-year CNY holidays with dramatic reduction of anthropogenic emissions.Two types of oxygenated OA(OOA)influenced by mixed emissions and SOA formation were found to be the dominant components during the lockdown in YRD region.Our results highlight that these emission-reduction-induced changes in organic aerosol need to be considered in the future to optimize air pollution control measures.
基金supported by the Ministry of Science and Technology of the People’s Republic of China(No.2017YFC0210000)the Young Talent Project of the Center for Excellence in Regional Atmospheric Environment,CAS(No.CERAE202002)+1 种基金the National Natural Science Foundation of China(No.41705110)Beijing Major Science and Technology Project(No.Z211100004321006)。
文摘Atmospheric oxidizing capacity(AOC)is an essential driving force of troposphere chemistry and self-cleaning,but the definition of AOC and its quantitative representation remain uncertain.Driven by national demand for air pollution control in recent years,Chinese scholars have carried out studies on theories of atmospheric chemistry and have made considerable progress in AOC research.This paper will give a brief review of these developments.First,AOC indexes were established that represent apparent atmospheric oxidizing ability(AOIe)and potential atmospheric oxidizing ability(AOIp)based on aspects of macrothermodynamics and microdynamics,respectively.A closed study refined the quantitative contributions of heterogeneous chemistry to AOC in Beijing,and these AOC methods were further applied in Beijing-Tianjin-Hebei and key areas across the country.In addition,the detection of ground or vertical profiles for atmospheric OH·,HO_(2)·,NO_(3)·radicals and reservoir molecules can now be obtained with domestic instruments in diverse environments.Moreover,laboratory smoke chamber simulations revealed heterogeneous processes involving reactions of O_(3)and NO_(2),which are typical oxidants in the surface/interface atmosphere,and the evolutionary and budgetary implications of atmospheric oxidants reacting under multispecies,multiphase and multi-interface conditions were obtained.Finally,based on the GRAPES-CUACE adjoint model improved by Chinese scholars,simulations of key substances affecting atmospheric oxidation and secondary organic and inorganic aerosol formation have been optimized.Normalized numerical simulations of AOIe and AOIp were performed,and regional coordination of AOC was adjusted.An optimized plan for controlling O_(3)and PM2.5was analyzed by scenario simulation.
基金supported by the National Natural Science Foundation of China(nos.21822805,21908065,31871430,81802979,818800585,and 8180032537)Young Medical Talents Training Program of Shanghai(2018)+3 种基金the Commission of Science and Technology of Shanghai Municipality(no.18430711000)the Australian National Health and Medical Research Council(nos.APP1126091 and APP1125794)the Science and Technology Commission of Shanghai Municipality for the Shanghai International Cooperation Program(18430711000)the China Postdoctoral Science Foundation(nos.2019M651427 and 2020T130197),W.Yang acknowledges the financial support of the innovative research team of high-level local universities in Shanghai.
文摘Ratiometric probes facilitate quantitative studies via self-calibration and are cherished for bioimaging.Often,a small probe-product spectral separation leads to crosstalk,but the rational development of ratiometric probes with zero probe-product crosstalk remains challenging.Harnessing the recent progress on photophysical modulation of xanthenoid fluorochromes,we propose a powerful and versatile probe design principle,that is,“bridging-group modification,”and developed totalROX,a robust probe for monitoring the total cellular oxidative capacity.
基金financially supported by the National Natural Science Foundation of China (20637020, 40490265 & 20077001)National Basic Research Program of China (2002CB410802)special fund of State Key Joint Laboratory of Environment Simulation and Pollution Control
文摘Urban and regional air pollutions are characterized by high concentrations of secondary pollutants such as photo-oxidants (mainly ozone) and fine particulate matter, which are formed through chemical reactions of the primary pollutants emitted from various sources. The accumulation of these pollutants under stagnant meteorological conditions results in the formation of gray haze, reducing visibility and causing major impacts on human health and climate. In an air pollution complex, the co- existence of high concentrations of primary and secondary gaseous and particulate pollutants provides a large amount of reac- tants for heterogeneous reactions on the surface of fine particles; these reactions change the oxidizing capacity of the atmos- phere, as well as chemical compositions along with the physicochemical and optical properties of particulate matter, thereby accelerating formation of the air pollution complex and gray haze. Using in situ technologies, such as diffuse reflectance infra- red Fourier-transform spectroscopy and single-particle Raman spectroscopy, we systematically investigated the reaction kinet- ics and mechanisms of gaseous pollutants (i.e., NO2, SO2, 03, and formaldehyde) on the surfaces of the major components of atmospheric particles such as CaCO3, kaolinite, montmorillonite, NaC1, sea salt, A1203, and Tit2. We found that the main re- action products were sulfate, nitrate, or formate, which can change the hygroscopicity and light extinction parameters of those particles significantly. By analyzing the reaction kinetics of these heterogeneous reactions, we identified synergetic mechanisms of the three ternary reaction systems, ,i.e., NOE-particles-H2O, SO2-particles-O3, and organics/SO2-particles-UV illumination. These synergetic mechanisms can provide experimental and theoretical bases for understanding the feedback mechanisms and nonlinear processes in the formation of an air pollution complex and gray haze.