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| 1 | Characteristics of PM_(2.5) pollution in Beijing after the improvement of air quality显示文摘Following the implementation of the strictest clean air policies to date in Beijing,the physicochemical characteristics and sources of PM_(2.5) have changed over the past few years.To improve pollution reduction policies and subsequent air quality further,it is necessary to explore the changes in PM_(2.5) over time.In this study,over one year(2017-2018)field study based on filter sampling(TH-150C;Wuhan Tianhong,China)was conducted in Fengtai District,Beijing,revealed that the annual average PM_(2.5) concentration(64.8±43.1μg/m^3)was significantly lower than in previous years and the highest PM_(2.5) concentration occurred in spring(84.4±59.9μg/m^3).Secondary nitrate was the largest source and accounted for 25.7%of the measured PM_(2.5).Vehicular emission,the second largest source(17.6%),deserves more attention when considering the increase in the number of motor vehicles and its contribution to gaseous pollutants.In addition,the contribution from coal combustion to PM_(2.5) decreased significantly.During weekends,the contribution from EC and NO3−increased whereas the contributions from SO4^2−,OM,and trace elements decreased,compared with weekdays.During the period of residential heating,PM_(2.5) mass decreased by 23.1%,compared with non-heating period,while the contributions from coal combustion and vehicular emission,and related species increased.With the aggravation of pollution,the contribution of vehicular emission and secondary sulfate increased and then decreased,while the contribution of NO3−and secondary nitrate continued to increase,and accounted for 34.0%and 57.5%of the PM_(2.5) during the heavily polluted days,respectively. | Xiaojuan Huang Guiqian Tang Junke Zhang Baoxian Liu Chao Liu Jin Zhang Leilei Cong Mengtian Cheng Guangxuan Yan Wenkang Gao Yinghong Wang Yuesi Wang | 2021 | Journal of Environmental Sciences2021，33，2： | 14 |
| 2 | Emerging transporter-targeted nanoparticulate drug delivery systems显示文摘Transporter-targeted nanoparticulate drug delivery systems(nano-DDS) have emerged as promising nanoplatforms for efficient drug delivery. Recently, great progress in transporter-targeted strategies has been made, especially with the rapid developments in nanotherapeutics. In this review, we outline the recent advances in transporter-targeted nano-DDS. First, the emerging transporter-targeted nano-DDS developed to facilitate oral drug delivery are reviewed. These include improvements in the oral absorption of protein and peptide drugs, facilitating the intravenous-to-oral switch in cancer chemotherapy. Secondly, the recent advances in transporter-assisted brain-targeting nano-DDS are discussed,focusing on the specific transporter-based targeting strategies. Recent developments in transportermediated tumor-targeting drug delivery are also discussed. Finally, the possible transport mechanisms involved in transporter-mediated endocytosis are highlighted, with special attention to the latest findings of the interactions between membrane transporters and nano-DDS. | Hongyan Su Yan Wang Shuo Liu Yue Wang Qian Liu Guangxuan Liu Qin Chen | 2019 | Acta Pharmaceutica Sinica B2019，9，1： | 9 |
| 3 | Chemical characteristics and source apportionment of PM_(2.5) in a petrochemical city: Implications for primary and secondary carbonaceous component显示文摘To study the pollution features and underlying mechanism of PM_(2.5) in Luoyang, a typical developing urban site in the central plain of China, 303 PM_(2.5) samples were collected from April 16 to December 29, 2015 to analyze the elements, water soluble inorganic ions, organic carbon and elemental carbon. The annual mean concentration of PM_(2.5) was 142.3 μg/m^(3), and 75% of the daily PM_(2.5) concentrations exceeded the 75 μg/m^(3). The secondary inorganic ions, organic matter and mineral dust were the most abundant species, accounting for 39.6%, 19.2% and 9.3% of the total mass concentration, respectively. But the major chemical components showed clear seasonal dependence. SO_(4)^(2-) was most abundant specie in spring and summer, which related to intensive photochemical reaction under high O_3 concentration. In contrast, the secondary organic carbon and ammonium while primary organic carbon and ammonium significantly contributed to haze formation in autumn and winter, respectively. This indicated that the collaboration effect of secondary inorganic aerosols and carbonaceous matters result in heavy haze in autumn and winter. Six main sources were identified by positive matrix factorization model: industrial emission, combustion sources, traffic emission, mineral dust, oil combustion and secondary sulfate, with the annual contribution of 24%, 20%, 24%, 4%, 5% and 23%, respectively. The potential source contribution function analysis pointed that the contribution of the local and short-range regional transportation had significant impact. This result highlighted that local primary carbonaceous and precursor of secondary carbonaceous mitigation would be key to reduce PM_(2.5) and O_3 during heavy haze episodes in winter and autumn. | Guangxuan Yan Puzhen Zhang Jie Yang Jingwen Zhang Guifen Zhu Zhiguo Cao Jing Fan Zirui Liu Yuesi Wang | 2021 | Journal of Environmental Sciences2021，33，5： | 6 |
| 4 | Two-year simultaneous records of N 2 O and NO fluxes from a farmed cropland in the northern China plain with a reduced nitrogen addition rate by one-third显示文摘 | Guangxuan Yan Xunhua Zheng Feng Cui Zhisheng Yao Zaixing Zhou Jia Deng Yu Xu | 2013 | Agriculture, Ecosystems and Environment2013，，： | 1 |
| 5 | Chemical characterization and source identification of PM_(2.5) in Luoyang after the clean air actions显示文摘Luoyang is a typical heavy industrial city in China,with a coal-dominated energy structure and serious air pollution.Following the implementation of the clean air actions,the physic-ochemical characteristics and sources of PM_(2.5) have changed.A comprehensive study of PM_(2.5) was conducted from October 16,2019 to January 23,2020 to evaluate the effectiveness of previous control measures and further to provide theory basis for more effective policies in the future.Results showed that the aerosol pollution in Luoyang in autumn and win-ter is still serious with the average concentration of 91.1 μg/m^(3),although a large reduction(46.9%)since 2014.With the contribution of nitrate increased from 12.5%to 25.1%and sul-fate decreased from 16.7%to 11.2%,aerosol pollution has changed from sulfate-dominate to nitrate-dominate.High NO_(3)^(-)/SO_(4)^(2-)ratio and the increasing of NO_(3)^(-)/SO_(4)^(2-)ratio with the aggravation of pollution indicating vehicle exhaust playing an increasingly important role in PM_(2.5) pollution in Luoyang,especially in the haze processes.Secondary inorganic ions contributed significantly to the enhancement of PM_(2.5) during the pollution period.The high value of Cl^(-)/Na^(+)and EC concentration indicate coal combustion in Luoyang is still serious.The top three contributor sources were secondary inorganic aerosols(33.3%),coal combus-tion(13.6%),and industrial emissions(13.4%).Close-range transport from the western and northeastern directions were more important factors in air pollution in Luoyang during the sampling period.It is necessary to strengthen the control of coal combustion and reduce vehicle emissions in future policies. | Min Xu Zirui Liu Bo Hu Guangxuan Yan Jianan Zou Shuman Zhao Jingxiang Zhou Xianhui Liu Xueping Zheng Xiaoyan Zhang Jing Cao Mengshuang Guan Yirong Lv Yanyun Zhang | 2022 | Journal of Environmental Sciences2022，34，5： | 1 |
| 6 | A Meta-analysis of No-tillage Effects on Greenhouse Gas Emissions from Wheat-based Rotation Cropping Agroecosystem in China显示文摘Globally,agricultural soils are considered as one of the most important sources of greenhouse gas(GHG)emissions.No-tillage(NT),one of the most admired ways of climate-smart agriculture,has been deemed to have co-benefit to mitigation of GHG emissions and sustainability for crop yield,however,the effect of NT on GHG emissions is controversial.This study analyzed the overall effects of NT on GHG emissions,as well as the moderators that significantly influenced the overall effects,of the wheat-based rotation cropping systems in China through meta-analysis.The results showed that the overall effect size of NT on methane(CH4)uptake,nitrous oxide(N2O)emission,and global warming potential(GWP)was 0.70(95%Confidence Interval(CI):0.21–1.19),-0.27(95%CI:-0.72–0.18),and-0.39(95%CI:-1.01–0.23),respectively.In temperate climate zones with alkaline soils,the nitrogen application rate of 120–240 kg/ha,NT could significantly reduce GHG emissions and GWP.However,the mitigation effect will be weakened along with NT duration,except for proper straw addition.Overall,NT has the potential to reduce GHG emissions from wheat-based rotation systems in China,but it is necessary to implement NT depending on local conditions,soil characteristics,and field management. | YAN Guangxuan WANG Jieqi LUO Tingting CHEN Weiwei SHAO Yun LI Chunxi | 2023 | Chinese Geographical Science2023，33，3： | 0 |
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