Benthic biofilms,the aggregates of multi-trophic microorganisms,play an important role in nitrogen cycling in aquatic ecosystems and are significantly influenced by flow velocity.Nevertheless,the roles of multi-trophi...Benthic biofilms,the aggregates of multi-trophic microorganisms,play an important role in nitrogen cycling in aquatic ecosystems and are significantly influenced by flow velocity.Nevertheless,the roles of multi-trophic microbial communities in nitrogen cycling of benthic biofilms remain unclear,especially under flow velocity conditions.In this study,we investigated how low trophic level microbial communities(bacteria,fungi,and algae),primary predator(protozoa)and secondary predator(metazoan)mediate the nitrogen cycling in benthic biofilms under low(0.05 m/s)moderate(0.1 m/s)and high(0.15 m/s)flow velocity conditions.The results showed that the activities of ammonia monooxygenase,nitrate reductase and nitrite reductase in benthic biofilms under high flow velocity increased 26.32%,18.66%,and 10.46%,respectively,compared with those under low flow velocity.Metagenomic sequencing analysis indicated that high flow velocity enhanced the relative abundances of functional genes involved in nitrification(amoABC)and denitrification(narG,nirK,and nirS).Compared with other trophic level microorganisms,the bacterial richness had the highest explanation(42.36%)for the variation in ammonia monooxygenase,and the variations in activities of nitrate reductase and nitrite reductase were explained 33.29%and 36.68%by protozoan richness,respectively.High richness index might promote nitrification and denitrification process via upregulating amino acid transport and metabolism,and signal transduction mechanisms.The negative cross trophic associations(potential predation activity)enhanced nitrification and denitrification by promoting microbial activity further enhancing ATPase activity and potential electron donor production.This study provides a new understanding of how multi-trophic microorganisms regulate the nitrogen cycling in benthic biofilms under increased flow velocity,which will benefit river management.展开更多
We propose a new method to estimate surface-level particulate matter(PM)concentrations by using satellite-retrieved Aerosol Optical Thickness(AOT).This method considers the distribution and variation of Planetary Boun...We propose a new method to estimate surface-level particulate matter(PM)concentrations by using satellite-retrieved Aerosol Optical Thickness(AOT).This method considers the distribution and variation of Planetary Boundary Layer(PBL)height and relative humidity(RH)at the regional scale.The method estimates surface-level particulate matter concentrations using the data simulated by an atmospheric boundary layer model RAMS and satellite-retrieved AOT.By incorporation MODIS AOT,PBL height and RH simulated by RAMS,this method is applied to estimate the surface-level PM 2.5 concentrations in North China region.The result is evaluated by using 16 ground-based observations deployed in the research region,and the result shows a good agreement between estimated PM 2.5 concentrations and observations,and the coefficient of determination R2 is 0.61 between the estimated PM 2.5 concentrations and the observations.In addition,surface-level PM 2.5 concentrations are also estimated by using MODIS AOT,ground-based LIDAR observations and RH measurements.A comparison between the two estimated PM 2.5 concentrations shows that the new method proposed in this paper is better than the traditional method.The coefficient of determination R2 is improved from 0.32 to 0.62.展开更多
Background： As a novel molecular markerof non-small cell lung cancer （NSCLC）, PRDI-BFI and R1Z homology domain containing protein 14 （PRDM 14） is over-expressed ill NSCLC tumor tissues. Extracellular matrix degra...Background： As a novel molecular markerof non-small cell lung cancer （NSCLC）, PRDI-BFI and R1Z homology domain containing protein 14 （PRDM 14） is over-expressed ill NSCLC tumor tissues. Extracellular matrix degradation mediated by the balance between matrix metalloproteinases （MMPs） and tissue inhibitor of metalloproteinases （TIMPs） is one of the most important mechanism in king cancer metastasis. This study aimed to determine if PRDM14 promoted the migration of NSCLC cells through extracellular matrix degradation mediated by change of MMP/TIMP expression. Methods： The expression of PRDM 14 was down-regulated in human cell line A 549 after transfection with lentiviral vector-mediated short-hairpin ribonucleic acids （shRNAs） which targeted the PRDM 14 promoter. Cellular migration ofshRNA-infected cells was detected by a scratch wound healing assay and transwell cell rnigration assay. Expression levels of MMP1, MMP2, TIMP1, and TIMP2 were measured by quantitative real-time polymerase chain reaction （RT-PCR）. Results： Migration of PRDM 14-shRNA-infected cells was significantly inhibited relative to control cells as measured by the scratch wound healing （P 〈 0.05） and transwell cell migration assays （P 〈 0.01 ）. The expression of MMPI in A549 cells infected by PRDMI4-shRNA was down-regulated significantly （P 〈 0.01 ）, whereas the expression ofTIMP 1 and TIMP2 was up-regulated significantly （P 〈 0.01 ）. Conclusions： PRDM 14 accelerates A549 cells migration in vitro through extracellular matrix degradation. PRDM 14 is considered as a potential therapeutic target in metastatic NSCLC.展开更多
Travelling is a critical component of daily life.With new technology,personalized travel route recommendations are possible and have become a new research area.A personalized travel route recommendation refers to plan...Travelling is a critical component of daily life.With new technology,personalized travel route recommendations are possible and have become a new research area.A personalized travel route recommendation refers to plan an optimal travel route between two geographical locations,based on the road networks and users’travel preferences.In this paper,we define users’travel behaviours from their historical Global Positioning System(GPS)trajectories and propose two personalized travel route recommendation methods–collaborative travel route recommendation(CTRR)and an extended version of CTRR(CTRR+).Both methods consider users’personal travel preferences based on their historical GPS trajectories.In this paper,we first estimate users’travel behaviour frequencies by using collaborative filtering technique.A route with the maximum probability of a user’s travel behaviour is then generated based on the naïve Bayes model.The CTRR+method improves the performances of CTRR by taking into account cold start users and integrating distance with the user travel behaviour probability.This paper also conducts some case studies based on a real GPS trajectory data set from Beijing,China.The experimental results show that the proposed CTRR and CTRR+methods achieve better results for travel route recommendations compared with the shortest distance path method.展开更多
Background：Protein arginine methyltransferases 1 （PRMT1） is over-expressed in a variety of cancers,including lung cancer,and is correlated with a poor prognosis of tumor development.This study aimed to investigate ...Background：Protein arginine methyltransferases 1 （PRMT1） is over-expressed in a variety of cancers,including lung cancer,and is correlated with a poor prognosis of tumor development.This study aimed to investigate the role of PRMT1 in nonsmall cell lung cancer （NSCLC） migration in vitro.Methods：In this study,PRMT1 expression in the NSCLC cell line A549 was silenced using lentiviral vector-mediated short hairpin RNAs.Cell migration was measured using both scratch wound healing and transwell cell migration assays.The mRNA expression levels of matrix metalloproteinase 2 （MMP-2） and tissue inhibitor ofmetalloproteinase 1,2 （TIMP l,2） were measured using quantitative real-time reverse transcription-polymerase chain reaction.The expression levels of protein markers for epithelial-mesenchymal transition （EMT） （E-cadherin,N-cadherin）,focal adhesion kinase （FAK）,Src,AKT,and their corresponding phosphorylated states were detected by Western blot.Results：Cell migration was significantly inhibited in the PRMT1 silenced group compared to the control group.The mRNA expression of MMP-2 decreased while TIMP 1 and TIMP2 increased significantly.E-cadherin mRNA expression also increased while N-cadherin decreased.Only phosphorylated Src levels decreased in the silenced group while FAK or AKT remained unchanged.Conclusions：PRMT1-small hairpin RNA inhibits the migration abilities of NSCLC A549 cells by inhibiting EMT,extracellular matrix degradation,and Src phosphorylation in vitro.展开更多
《1990年移民与国籍法》(the1990Immigration and Nationality Act)颁布以来,在美印裔族群迎来了又一次大发展,不仅在规模上成为继华裔之后的最大亚裔群体,而且积极参与到美国社会生活中,成为美国最重要的外来族群之一。本文分析了1990...《1990年移民与国籍法》(the1990Immigration and Nationality Act)颁布以来,在美印裔族群迎来了又一次大发展,不仅在规模上成为继华裔之后的最大亚裔群体,而且积极参与到美国社会生活中,成为美国最重要的外来族群之一。本文分析了1990年以来印度人以永久居民获得者、美国公民和合法非移民(Nonimmigrant)三种主要居留身份在美生活的发展历程,厘清了在美印度人的性别、年龄、职业、收入、婚姻、宗教信仰以及地域分布特征,认为印裔以其庞大的技术移民规模、高归化程度、良好的性别和年龄结构、优质的职业特征及稳定的家庭婚姻生活成为美国最成功的外来族群之一。展开更多
基金supported by the National Natural Science Foundation of China(Nos.52425902,52279061,and U2443217)the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(No.KYCX24_0905).
文摘Benthic biofilms,the aggregates of multi-trophic microorganisms,play an important role in nitrogen cycling in aquatic ecosystems and are significantly influenced by flow velocity.Nevertheless,the roles of multi-trophic microbial communities in nitrogen cycling of benthic biofilms remain unclear,especially under flow velocity conditions.In this study,we investigated how low trophic level microbial communities(bacteria,fungi,and algae),primary predator(protozoa)and secondary predator(metazoan)mediate the nitrogen cycling in benthic biofilms under low(0.05 m/s)moderate(0.1 m/s)and high(0.15 m/s)flow velocity conditions.The results showed that the activities of ammonia monooxygenase,nitrate reductase and nitrite reductase in benthic biofilms under high flow velocity increased 26.32%,18.66%,and 10.46%,respectively,compared with those under low flow velocity.Metagenomic sequencing analysis indicated that high flow velocity enhanced the relative abundances of functional genes involved in nitrification(amoABC)and denitrification(narG,nirK,and nirS).Compared with other trophic level microorganisms,the bacterial richness had the highest explanation(42.36%)for the variation in ammonia monooxygenase,and the variations in activities of nitrate reductase and nitrite reductase were explained 33.29%and 36.68%by protozoan richness,respectively.High richness index might promote nitrification and denitrification process via upregulating amino acid transport and metabolism,and signal transduction mechanisms.The negative cross trophic associations(potential predation activity)enhanced nitrification and denitrification by promoting microbial activity further enhancing ATPase activity and potential electron donor production.This study provides a new understanding of how multi-trophic microorganisms regulate the nitrogen cycling in benthic biofilms under increased flow velocity,which will benefit river management.
基金supported by National Department Public Benefit Research Foundation (Ministry of Environmental Protection of the People’s Republic of China) (Grant No. 201009001)National Natural Science Foundation of China (Grant No. 41101327)
文摘We propose a new method to estimate surface-level particulate matter(PM)concentrations by using satellite-retrieved Aerosol Optical Thickness(AOT).This method considers the distribution and variation of Planetary Boundary Layer(PBL)height and relative humidity(RH)at the regional scale.The method estimates surface-level particulate matter concentrations using the data simulated by an atmospheric boundary layer model RAMS and satellite-retrieved AOT.By incorporation MODIS AOT,PBL height and RH simulated by RAMS,this method is applied to estimate the surface-level PM 2.5 concentrations in North China region.The result is evaluated by using 16 ground-based observations deployed in the research region,and the result shows a good agreement between estimated PM 2.5 concentrations and observations,and the coefficient of determination R2 is 0.61 between the estimated PM 2.5 concentrations and the observations.In addition,surface-level PM 2.5 concentrations are also estimated by using MODIS AOT,ground-based LIDAR observations and RH measurements.A comparison between the two estimated PM 2.5 concentrations shows that the new method proposed in this paper is better than the traditional method.The coefficient of determination R2 is improved from 0.32 to 0.62.
文摘Background： As a novel molecular markerof non-small cell lung cancer （NSCLC）, PRDI-BFI and R1Z homology domain containing protein 14 （PRDM 14） is over-expressed ill NSCLC tumor tissues. Extracellular matrix degradation mediated by the balance between matrix metalloproteinases （MMPs） and tissue inhibitor of metalloproteinases （TIMPs） is one of the most important mechanism in king cancer metastasis. This study aimed to determine if PRDM14 promoted the migration of NSCLC cells through extracellular matrix degradation mediated by change of MMP/TIMP expression. Methods： The expression of PRDM 14 was down-regulated in human cell line A 549 after transfection with lentiviral vector-mediated short-hairpin ribonucleic acids （shRNAs） which targeted the PRDM 14 promoter. Cellular migration ofshRNA-infected cells was detected by a scratch wound healing assay and transwell cell rnigration assay. Expression levels of MMP1, MMP2, TIMP1, and TIMP2 were measured by quantitative real-time polymerase chain reaction （RT-PCR）. Results： Migration of PRDM 14-shRNA-infected cells was significantly inhibited relative to control cells as measured by the scratch wound healing （P 〈 0.05） and transwell cell migration assays （P 〈 0.01 ）. The expression of MMPI in A549 cells infected by PRDMI4-shRNA was down-regulated significantly （P 〈 0.01 ）, whereas the expression ofTIMP 1 and TIMP2 was up-regulated significantly （P 〈 0.01 ）. Conclusions： PRDM 14 accelerates A549 cells migration in vitro through extracellular matrix degradation. PRDM 14 is considered as a potential therapeutic target in metastatic NSCLC.
基金the Natural Sciences and Engineering Research Council of Canada Discovery Grant to Xin Wang,and the National Natural Science Foundation of China[grant number 11271351]to Jun Luo.
文摘Travelling is a critical component of daily life.With new technology,personalized travel route recommendations are possible and have become a new research area.A personalized travel route recommendation refers to plan an optimal travel route between two geographical locations,based on the road networks and users’travel preferences.In this paper,we define users’travel behaviours from their historical Global Positioning System(GPS)trajectories and propose two personalized travel route recommendation methods–collaborative travel route recommendation(CTRR)and an extended version of CTRR(CTRR+).Both methods consider users’personal travel preferences based on their historical GPS trajectories.In this paper,we first estimate users’travel behaviour frequencies by using collaborative filtering technique.A route with the maximum probability of a user’s travel behaviour is then generated based on the naïve Bayes model.The CTRR+method improves the performances of CTRR by taking into account cold start users and integrating distance with the user travel behaviour probability.This paper also conducts some case studies based on a real GPS trajectory data set from Beijing,China.The experimental results show that the proposed CTRR and CTRR+methods achieve better results for travel route recommendations compared with the shortest distance path method.
基金This study was supported by grants from the Natural Science Foundation of Huzhou City，the Public Welfare Technical Applied Research Project of Huzhou City （No.2013GY 19 No.2013（3Z14）.Conflict of Interest：None declared
文摘Background：Protein arginine methyltransferases 1 （PRMT1） is over-expressed in a variety of cancers,including lung cancer,and is correlated with a poor prognosis of tumor development.This study aimed to investigate the role of PRMT1 in nonsmall cell lung cancer （NSCLC） migration in vitro.Methods：In this study,PRMT1 expression in the NSCLC cell line A549 was silenced using lentiviral vector-mediated short hairpin RNAs.Cell migration was measured using both scratch wound healing and transwell cell migration assays.The mRNA expression levels of matrix metalloproteinase 2 （MMP-2） and tissue inhibitor ofmetalloproteinase 1,2 （TIMP l,2） were measured using quantitative real-time reverse transcription-polymerase chain reaction.The expression levels of protein markers for epithelial-mesenchymal transition （EMT） （E-cadherin,N-cadherin）,focal adhesion kinase （FAK）,Src,AKT,and their corresponding phosphorylated states were detected by Western blot.Results：Cell migration was significantly inhibited in the PRMT1 silenced group compared to the control group.The mRNA expression of MMP-2 decreased while TIMP 1 and TIMP2 increased significantly.E-cadherin mRNA expression also increased while N-cadherin decreased.Only phosphorylated Src levels decreased in the silenced group while FAK or AKT remained unchanged.Conclusions：PRMT1-small hairpin RNA inhibits the migration abilities of NSCLC A549 cells by inhibiting EMT,extracellular matrix degradation,and Src phosphorylation in vitro.
文摘《1990年移民与国籍法》(the1990Immigration and Nationality Act)颁布以来,在美印裔族群迎来了又一次大发展,不仅在规模上成为继华裔之后的最大亚裔群体,而且积极参与到美国社会生活中,成为美国最重要的外来族群之一。本文分析了1990年以来印度人以永久居民获得者、美国公民和合法非移民(Nonimmigrant)三种主要居留身份在美生活的发展历程,厘清了在美印度人的性别、年龄、职业、收入、婚姻、宗教信仰以及地域分布特征,认为印裔以其庞大的技术移民规模、高归化程度、良好的性别和年龄结构、优质的职业特征及稳定的家庭婚姻生活成为美国最成功的外来族群之一。
