Ambient benzene homologues were measured at a site in the northeastern urban area of Beijing, China, from August 24 to September 4, 2012 by SUMMA canister sampling followed by laboratory determination using cryogenic ...Ambient benzene homologues were measured at a site in the northeastern urban area of Beijing, China, from August 24 to September 4, 2012 by SUMMA canister sampling followed by laboratory determination using cryogenic cold trap pre-concentration-GC-MS/FID, and their health risks were also assessed. Daily total benzene homologues ranged from 0.99 to 49.71 μg/m3 with an average of 11.98 μg/m3. Benzene homologues showed higher concentrations in the morning and evening than that at noontime. Comparison with previous studies revealed a trend of decrease for ambient benzene homologues probably due to the effective emission control in Beijing in recent years. Vehicular exhaust was the main source while volatilization of paints and solvents also made substantial contributions. Health risk assessment showed that BTEX （benzene, toluene, ethylbenzene, o-xylene, m-xylene and p-xylene） and styrene had no appreciable adverse non-cancer health risks for the exposed population, while benzene has potential cancer risk of 1.34E-05. Available data from cities in China all implied that benzene imposes relatively higher cancer risk on the exposed populations and therefore strict control measures should be taken to further lower ambient benzene levels in China.展开更多
The pollution characteristics of surfactant substances in fine particles(PM_(2.5))in spring were studied in the Beibu Gulf Region of China,68 samples of PM_(2.5)were collected at Weizhou Island in Beihai City from Mar...The pollution characteristics of surfactant substances in fine particles(PM_(2.5))in spring were studied in the Beibu Gulf Region of China,68 samples of PM_(2.5)were collected at Weizhou Island in Beihai City from March 12 to April 17,2015.The Anionic Surfactant Substances(ASS)and Cationic Surfactant Substances(CSS)in the samples were analyzed using Byethyl Violet Spectrophotometry and Disulfide Blue Spectrophotometry,respectively.Combined with the data from backward trajectory simulation,the effects of air pollutants from remote transport on the pollution characteristics of surfactant substances in PM_(2.5)in the Beibu Gulf Region were analyzed and discussed.The results showed that the daily mean concentrations of ASS and CSS in spring in the Beibu Gulf Region were 165.20 pmol/m^(3)and 8.05 pmol/m^(3),and the variation ranges were 23.21–452.55 pmol/m^(3)and 0.65–31.31 pmol/m^(3),accounting for 1.82‰±1.65‰and 0.12‰±0.11‰of the mass concentration of PM_(2.5),respectively.These concentrations were lower than those in comparable regions around the world.There was no clear correlation between the concentrations of ASS and CSS in PM_(2.5)and the mass concentrations of PM_(2.5).Tourism and air transport had a positive contribution on the concentrations of ASS.The concentration of surfactant substances in PM_(2.5)was significantly impacted by wind speed and wind direction.Atmospheric temperature,air pressure and precipitation had little effect on the concentrations of surfactant substances.Surfactant substances in PM_(2.5)significantly impacted visibility.Results also showed that the main sources of surfactant substances were from the southern China and Southeast Asia.展开更多
MXR7 is a cell-surface protein and highly expressed in hepatocellular carcinoma(HCC). The aim of this study is to determine the expression profile of MXR7 in HCC and investigate the influence of MXR7 on invasion and m...MXR7 is a cell-surface protein and highly expressed in hepatocellular carcinoma(HCC). The aim of this study is to determine the expression profile of MXR7 in HCC and investigate the influence of MXR7 on invasion and metastasis of HCC cells. For this purpose, immunohistochemical assay was used to identify the differential expression of MXR7 in 94 HCC specimens. Expression of MXR7 in 4 pairs of HCC and portal vein tumor thrombus(PVTT) was also tested. The motility of HCC cells were characterized by transwell migration and matrigel invasion assays. In vivo metastasis potential was determined via tail vein injection assay.Moreover, compared with noninvasive HCC tumors or human HCC cell lines with low metastatic potential, invasive HCC samples and HCC cell lines with high metastatic potential exhibited higher MXR7 expression. Furthermore, forced expression of MXR7 in SMMC-7721 promoted cell proliferation, migration and invasion in vitro and accelerated tumor growth and metastasis in vivo. Conversely, knockdown of MXR7 expression in HuH7 cells inhibited proliferation and motility of cells. Mechanically,overexpression of MXR7 promoted epithelial-mesenchymal transition(EMT) progress, and MXR7 depletion repressed the EMT phenotype. In conclusion, MXR7 is a mediator of EMT and metastasis in HCC and may serve as a novel therapeutic target.展开更多
The pneumatic conveying system of coal particles can greatly reduce the dust and improve the environmental quality at underground mining workface and the surrounding of coal enterprises.The particle shape and the inte...The pneumatic conveying system of coal particles can greatly reduce the dust and improve the environmental quality at underground mining workface and the surrounding of coal enterprises.The particle shape and the interaction coefficients between particles and the contact surface play important roles in the pneumatic conveying and CFD-DEM simulation.In order to build the semblable shape models and obtain the accurate interaction coefficients of large coal particles,this article establishes the con tact model by the particle overlap method and describes the mathematical model of the shape characteristics for large coal particle.The particle models are simulated by adopting the multi-index mixed orthogonal experiments.The accumulation density,the porosity and the error between simulation and experiment are taken as the indexes,and the particle models and the particle contact coefficients are taken as the orthogonal test factors.As a result,three more accurate particle models and their interaction coefficients are obtained,which provide the model basis for the pneumatic conveying of large coal particles.展开更多
基金supported by the Special Research Project for the National Environmental Protection Public Welfare Industry of China(No.201009032)the Strategic Pilot Science and Technology Project of Chinese Academy of Sciences(Class B)(No.XDB05010200)the Project of National Natural Science Foundation of China(No.41175111)
文摘Ambient benzene homologues were measured at a site in the northeastern urban area of Beijing, China, from August 24 to September 4, 2012 by SUMMA canister sampling followed by laboratory determination using cryogenic cold trap pre-concentration-GC-MS/FID, and their health risks were also assessed. Daily total benzene homologues ranged from 0.99 to 49.71 μg/m3 with an average of 11.98 μg/m3. Benzene homologues showed higher concentrations in the morning and evening than that at noontime. Comparison with previous studies revealed a trend of decrease for ambient benzene homologues probably due to the effective emission control in Beijing in recent years. Vehicular exhaust was the main source while volatilization of paints and solvents also made substantial contributions. Health risk assessment showed that BTEX （benzene, toluene, ethylbenzene, o-xylene, m-xylene and p-xylene） and styrene had no appreciable adverse non-cancer health risks for the exposed population, while benzene has potential cancer risk of 1.34E-05. Available data from cities in China all implied that benzene imposes relatively higher cancer risk on the exposed populations and therefore strict control measures should be taken to further lower ambient benzene levels in China.
基金supported by the Project of Natural Science Foundation of China(Nos.4117511121177078)the Project of Environmental Protection Public Science and Technology Research Fund(No.201309016)。
文摘The pollution characteristics of surfactant substances in fine particles(PM_(2.5))in spring were studied in the Beibu Gulf Region of China,68 samples of PM_(2.5)were collected at Weizhou Island in Beihai City from March 12 to April 17,2015.The Anionic Surfactant Substances(ASS)and Cationic Surfactant Substances(CSS)in the samples were analyzed using Byethyl Violet Spectrophotometry and Disulfide Blue Spectrophotometry,respectively.Combined with the data from backward trajectory simulation,the effects of air pollutants from remote transport on the pollution characteristics of surfactant substances in PM_(2.5)in the Beibu Gulf Region were analyzed and discussed.The results showed that the daily mean concentrations of ASS and CSS in spring in the Beibu Gulf Region were 165.20 pmol/m^(3)and 8.05 pmol/m^(3),and the variation ranges were 23.21–452.55 pmol/m^(3)and 0.65–31.31 pmol/m^(3),accounting for 1.82‰±1.65‰and 0.12‰±0.11‰of the mass concentration of PM_(2.5),respectively.These concentrations were lower than those in comparable regions around the world.There was no clear correlation between the concentrations of ASS and CSS in PM_(2.5)and the mass concentrations of PM_(2.5).Tourism and air transport had a positive contribution on the concentrations of ASS.The concentration of surfactant substances in PM_(2.5)was significantly impacted by wind speed and wind direction.Atmospheric temperature,air pressure and precipitation had little effect on the concentrations of surfactant substances.Surfactant substances in PM_(2.5)significantly impacted visibility.Results also showed that the main sources of surfactant substances were from the southern China and Southeast Asia.
基金supported by the National Natural Science Foundation of China(81622039,81572895,81372356,81221061)Shanghai Subject Chief Scientist(14XD1400100)
文摘MXR7 is a cell-surface protein and highly expressed in hepatocellular carcinoma(HCC). The aim of this study is to determine the expression profile of MXR7 in HCC and investigate the influence of MXR7 on invasion and metastasis of HCC cells. For this purpose, immunohistochemical assay was used to identify the differential expression of MXR7 in 94 HCC specimens. Expression of MXR7 in 4 pairs of HCC and portal vein tumor thrombus(PVTT) was also tested. The motility of HCC cells were characterized by transwell migration and matrigel invasion assays. In vivo metastasis potential was determined via tail vein injection assay.Moreover, compared with noninvasive HCC tumors or human HCC cell lines with low metastatic potential, invasive HCC samples and HCC cell lines with high metastatic potential exhibited higher MXR7 expression. Furthermore, forced expression of MXR7 in SMMC-7721 promoted cell proliferation, migration and invasion in vitro and accelerated tumor growth and metastasis in vivo. Conversely, knockdown of MXR7 expression in HuH7 cells inhibited proliferation and motility of cells. Mechanically,overexpression of MXR7 promoted epithelial-mesenchymal transition(EMT) progress, and MXR7 depletion repressed the EMT phenotype. In conclusion, MXR7 is a mediator of EMT and metastasis in HCC and may serve as a novel therapeutic target.
基金the Natural Science Foundation ofjiangsu Province(BK20170241)the National Natural Science Foundation of China(51705222 and 51675521)supported by the State Key Laboratory of Process Automation in Mining&Metallurgy and the Beijing Key Laboratory of Process Automation in Mining&Metallurgy(BGRIMM-KZSKL-2019-07).
文摘The pneumatic conveying system of coal particles can greatly reduce the dust and improve the environmental quality at underground mining workface and the surrounding of coal enterprises.The particle shape and the interaction coefficients between particles and the contact surface play important roles in the pneumatic conveying and CFD-DEM simulation.In order to build the semblable shape models and obtain the accurate interaction coefficients of large coal particles,this article establishes the con tact model by the particle overlap method and describes the mathematical model of the shape characteristics for large coal particle.The particle models are simulated by adopting the multi-index mixed orthogonal experiments.The accumulation density,the porosity and the error between simulation and experiment are taken as the indexes,and the particle models and the particle contact coefficients are taken as the orthogonal test factors.As a result,three more accurate particle models and their interaction coefficients are obtained,which provide the model basis for the pneumatic conveying of large coal particles.
