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| 1 | The levels, sources and reactivity of volatile organic compounds in a typical urban area of Northeast China显示文摘Air concentrations of volatile organic compounds(VOCs) were continually measured at a monitoring site in Shenyang from 20 August to 16 September 2017. The average concentrations of alkanes, alkenes, aromatics and carbonyls were 28.54, 6.30, 5.59 and9.78 ppbv, respectively. Seven sources were identified by the Positive Matrix Factorization model based on the measurement data of VOCs and CO. Vehicle exhaust contributed the most(36.15%) to the total propene-equivalent concentration of the measured VOCs,followed by combustion emission(16.92%), vegetation emission and secondary formation(14.33%), solvent usage(10.59%), petrochemical industry emission(9.89%), petrol evaporation(6.28%), and liquefied petroleum gas(LPG) usage(5.84%). Vehicle exhaust, solvent usage and combustion emission were found to be the top three VOC sources for O_3 formation potential, accounting for 34.52%, 16.55% and 11.94%, respectively. The diurnal variation of the total VOCs from each source could be well explained by their emission characteristics,e.g., the two peaks of VOC concentrations from LPG usage were in line with the cooking times for breakfast and lunch. Wind rose plots of the VOCs from each source could reveal the possible distribution of the sources around the monitoring site. The O_3 pollution episodes during the measurement period were found to be coincident with the elevation of VOCs, which was mainly due to the air parcel from the southeast direction where petrochemical industry emission was found to be dominant, suggesting that the petrochemical industry emission from the southeast was probably a significant cause of O_3 pollution in Shenyang. | Zhuobiao Ma Chengtang Liu Chenglong Zhang Pengfei Liu Can Ye Chaoyang Xue Di Zhao Jichen Sun Yiming Du Fahe Chai Yujing Mu | 2019 | Journal of Environmental Sciences2019,31,5: | 12 |
| 2 | Early changes to the extracellular space in the hippocampus under simulated microgravity conditions显示文摘The smooth transportation of substances through the brain extracellular space(ECS)is crucial to maintaining brain function;however,the way this occurs under simulated microgravity remains unclear.In this study,tracer-based magnetic resonance imaging(MRI)and DECS-mapping techniques were used to image the drainage of brain interstitial fluid(ISF)from the ECS of the hippocampus in a tail-suspended hindlimb-unloading rat model at day 3(HU-3)and 7(HU-7).The results indicated that drainage of the ISF was accelerated in the HU-3 group but slowed markedly in the HU-7 group.The tortuosity of the ECS decreased in the HU-3 group but increased in the HU-7 group,while the volume fraction of the ECS increased in both groups.The diffusion rate within the ECS increased in the HU-3 group and decreased in the HU-7 group.The alterations to ISF drainage and diffusion in the ECS were recoverable in the HU-3 group,but neither parameter was restored in the HU-7 group.Our findings suggest that early changes to the hippocampal ECS and ISF drainage under simulated microgravity can be detected by tracer-based MRI,providing a new perspective for studying microgravity-induced nano-scale structure abnormities and developing neuroprotective approaches involving the brain ECS. | Yajuan Gao Hongbin Han Jichen Du Qingyuan He Yanxing Jia Junhao Yan Hui Dai Bin Cui Jing Yang Xunbin Wei Liu Yang Rui Wang Ren Long Qiushi Ren Xing Yang Jiabin Lu | 2022 | Science China(Life Sciences)2022,65,3: | 2 |
| 3 | Correlation between Helicobacter pylori infection and atherothrombotic stroke显示文摘Previous studies have demonstrated that Helicobacter pylori infection is associated with coronary atherosclerotic heart disease, but the correlation between Helicobacter pylori infection and ischemic stroke remains unclear. The present study assessed the effects of Helicobacter pylori infection on atherothrombotic stroke. This study included 115 individuals with atherothrombotic stroke, all of whom were patients receiving treatment at the Department of Neurology, Aerospace Central Hos-pital (Aerospace Clinical Medical College Affiliated to Peking University) in China, from March 2006 to July 2009. In addition, 131 controls without the history of cardiovascular disease, cerebrovascular disease or atherothrombosis were also enrolled in the study. Results show that the Helicobacter pylori-IgG positive rate was greater in the atherothrombotic stroke patients than in the controls, but the difference was not statistically significant (67.8% vs. 61.8%, OR = 1.301, 95%CI: 0.769–2.203, P = 0.327). After correction for potential risk factors for Helicobacter pylori infection and known risk factors for ischemic stroke, no significant difference was detected between them (OR = 1.278, 95%CI: 0.667–2.449, P = 0.459). These results indicate that there is no specific correlation between Helicobacter pylori infection and atherothrombotic stroke. This finding requires further verification in large-sample prospective studies. | Xu Yang Xiaoli Zhao Yongjun Gao Zhidong Zheng Jilai Li Jichen Du Xinyi Li XianhaoXu Yingying Su | 2011 | Neural Regeneration Research2011,6,5: | 0 |