Microcystins(MCs) are cyclic hepatotoxic peptides produced by the bloom-forming cyanobacterium Microcystis and present a public health hazard to humans and livestock. The removal of MCs from contaminated water with po...Microcystins(MCs) are cyclic hepatotoxic peptides produced by the bloom-forming cyanobacterium Microcystis and present a public health hazard to humans and livestock. The removal of MCs from contaminated water with powdered activated carbon(PAC) has been employed as a simple and economic treatment strategy. In this study, PAC-Fe(Ⅲ) was prepared and utilized for the fast and efficient removal of MCs from water. PAC-Fe(Ⅲ) exhibited superior microcystin-LR(MC-LR) removal capacity and efficiency compared to the unmodified PAC. The MC-LR removal efficiency of PAC-Fe(Ⅲ) increased with decreasing p H within the pH range of 4.3 to 9.6. PAC-Fe(Ⅲ) could be reused for 3 times by methanol elution while the MC-LR removal efficiency was still over 70 percent. The removal efficiency was positively correlated to the ionic strength of water and negatively correlated to alkalinity. Natural organic matter(NOM) such as humic acid(HA) and salicylic acid(SA) generated low interference with MC-LR adsorption by PAC-Fe(Ⅲ). The complexation reaction between Fe^(3+) in PAC-Fe(Ⅲ) and the functional groups of MCLR was suggested as the key mechanism of MC-LR removal by PAC-Fe(Ⅲ). The results suggest that Femodified PAC is a promising material for the treatment of MC-contaminated waters.展开更多
We consider a bistable mesoscopic chemical reaction system and calculate entropy produc- tion along the dominant pathway during nonequilibrium phase transition. Using probability generating function method and eikonal...We consider a bistable mesoscopic chemical reaction system and calculate entropy produc- tion along the dominant pathway during nonequilibrium phase transition. Using probability generating function method and eikonal approximation, we first convert the chemical master equation into the classical Hamilton-Jacobi equation, and then find the dominant pathways between two steady states in the phase space by calculating zero-energy trajectories. We find that entropy productions are related to the actions of the forward and backward dominant pathways. At the coexistence point where the stabilities of the two steady states are equiv alent, both the system entropy change and the medium entropy change are zero; whereas at non-coexistence point both of them are nonzero.展开更多
The flipped classroom is an emerging teaching mode which is originated from the United States and is now prevalent in many countries. It is helpful to build a more harmonious relationship between the teachers and the ...The flipped classroom is an emerging teaching mode which is originated from the United States and is now prevalent in many countries. It is helpful to build a more harmonious relationship between the teachers and the students, to enhance the students＇ self-study ability, to create a favorable learning environment, to realize the individualized teaching in class, and to improve the students＇ English ability. The study focuses on the college English classroom in China. The author tries to prove that the flipped classroom is a helpful way to improve the teaching and learning effect of college English classroom. A teaching procedure for the flipped college English classroom is designed in the hope of changing the current college English teaching condition.展开更多
Our analysis of the surface aerosol and ultraviolet （UV） measurements in Pearl River Delta （PRD） region shows that the surface UV radiation is reduced by more than 50% due to high aerosol concentrations. This has ...Our analysis of the surface aerosol and ultraviolet （UV） measurements in Pearl River Delta （PRD） region shows that the surface UV radiation is reduced by more than 50% due to high aerosol concentrations. This has important impacts on urban ecosystem and photochemistry, especially on ozone photochemical production over the region. The quantitative effect of aerosols on surface ozone is evaluated by analyzing surface observations （including ozone, ultraviolet radiation, aerosol radiative parameters） and by using radiative and chemical models. A case study shows that the aerosol concentrations and UV radiation are significantly correlated with ozone concentrations. The correlation coefficient between the aerosol optical depth （AOD） and the PM10 mass concentration is very high, with a maximum of 0.98, and the AOD and UV radiation/ozone is anti- correlated, with a correlation coefficient of-0.90. The analysis suggests that ozone productivity is significantly decreased due to the reduction of UV radiation. The noon-time ozone maximum is considerably depressed when AOD is 0.6, and is further decreased when AOD is up to 1.2 due to the reduction of ozone photochemical productivity. Because the occurring probability of aerosol optical depth for AOD550m≥0.6 and AOD340mm ≥1.0 is 47, and 55% respectively during the dry season （October, November, December, January）, this heavy aerosol condition explains the low ozone maximum that often occurs in the dry season over the Guangzhou region. The analysis also suggests that the value of single scattering albedo （SSA） is very sensitive to the aerosol radiative effect when the radiative and chemical models are applied, implying that the value of SSA needs to be carefully studied when the models are used in calculating ozone production.展开更多
The spatiotemporal expression of genes is sophisticatedly controlled through three main layers: transcriptional, translational and post-translational. Now increasing chemical modifications are discovered on genomic DN...The spatiotemporal expression of genes is sophisticatedly controlled through three main layers: transcriptional, translational and post-translational. Now increasing chemical modifications are discovered on genomic DNA, RNA and proteins. These modifications are recognized as additional layer of regulatory mechanisms in controlling gene expression that defines cell status. So far,more than 150 chemical modifications are identified in nucleic acids,and more than 400 discrete types of modifications are identified in proteins. How these modifications are interpreted are fundamental questions to our understanding of living organisms. The omics sciences of systems biology, including genomics, transcriptomics, proteomics, and metabolomics, have been in existence for decades. Due to the large numbers of modifications occurring in DNA, RNA and proteins with regulatory roles, we propose the modificaomics from the words of modification and omics. Modificaomics mainly refers to the comprehensive study of the modifications on DNA, RNA and proteins. In this review, we conceive modificaomics by introducing the discovered modifications in DNA, RNA and proteins as well as summarizing their biological functions. We hope the proposed modificaomics can provide a whole picture of modifications of these biopolymers and simulate the study of the functions of the modifications on DNA, RNA and proteins.展开更多
Microbial oceanography is an emerging discipline resulted from the interaction,cross-fertilization and integration of life science and ocean science.Microbial oceanography integrates the principles of marine microbiol...Microbial oceanography is an emerging discipline resulted from the interaction,cross-fertilization and integration of life science and ocean science.Microbial oceanography integrates the principles of marine microbiology,microbial ecology and oceanography to study the role of microorganisms in the biogeochemical dynamics of natural marine ecosystems.The application of genomics tools to study marine microbes is resulting in rapid advancements in microbial oceanography that has important implications in global carbon cycle,climate change,and ecosystem function.Here we review the application of genomics and metagenomics in microbial oceanography and suggest future directions in microbial oceanography research.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.31660138,31400405)the Jiangxi Water Science and Technology Fund(Nos.TG201501,KT201602)the Science and Technology Project from Ministry of Water Resources,China(Nos.ZXKT201508,SKY201503)
文摘Microcystins(MCs) are cyclic hepatotoxic peptides produced by the bloom-forming cyanobacterium Microcystis and present a public health hazard to humans and livestock. The removal of MCs from contaminated water with powdered activated carbon(PAC) has been employed as a simple and economic treatment strategy. In this study, PAC-Fe(Ⅲ) was prepared and utilized for the fast and efficient removal of MCs from water. PAC-Fe(Ⅲ) exhibited superior microcystin-LR(MC-LR) removal capacity and efficiency compared to the unmodified PAC. The MC-LR removal efficiency of PAC-Fe(Ⅲ) increased with decreasing p H within the pH range of 4.3 to 9.6. PAC-Fe(Ⅲ) could be reused for 3 times by methanol elution while the MC-LR removal efficiency was still over 70 percent. The removal efficiency was positively correlated to the ionic strength of water and negatively correlated to alkalinity. Natural organic matter(NOM) such as humic acid(HA) and salicylic acid(SA) generated low interference with MC-LR adsorption by PAC-Fe(Ⅲ). The complexation reaction between Fe^(3+) in PAC-Fe(Ⅲ) and the functional groups of MCLR was suggested as the key mechanism of MC-LR removal by PAC-Fe(Ⅲ). The results suggest that Femodified PAC is a promising material for the treatment of MC-contaminated waters.
文摘We consider a bistable mesoscopic chemical reaction system and calculate entropy produc- tion along the dominant pathway during nonequilibrium phase transition. Using probability generating function method and eikonal approximation, we first convert the chemical master equation into the classical Hamilton-Jacobi equation, and then find the dominant pathways between two steady states in the phase space by calculating zero-energy trajectories. We find that entropy productions are related to the actions of the forward and backward dominant pathways. At the coexistence point where the stabilities of the two steady states are equiv alent, both the system entropy change and the medium entropy change are zero; whereas at non-coexistence point both of them are nonzero.
文摘The flipped classroom is an emerging teaching mode which is originated from the United States and is now prevalent in many countries. It is helpful to build a more harmonious relationship between the teachers and the students, to enhance the students＇ self-study ability, to create a favorable learning environment, to realize the individualized teaching in class, and to improve the students＇ English ability. The study focuses on the college English classroom in China. The author tries to prove that the flipped classroom is a helpful way to improve the teaching and learning effect of college English classroom. A teaching procedure for the flipped college English classroom is designed in the hope of changing the current college English teaching condition.
基金supported by National Natural Science Foundation of China (Grant Nos. 40875090, 40375002, 40775011)Natural Science Foundation of Guangdong Province (Grant No. 7035008)Tropical Marine Meteorological Science Foundation (Grant No. 200502)
文摘Our analysis of the surface aerosol and ultraviolet （UV） measurements in Pearl River Delta （PRD） region shows that the surface UV radiation is reduced by more than 50% due to high aerosol concentrations. This has important impacts on urban ecosystem and photochemistry, especially on ozone photochemical production over the region. The quantitative effect of aerosols on surface ozone is evaluated by analyzing surface observations （including ozone, ultraviolet radiation, aerosol radiative parameters） and by using radiative and chemical models. A case study shows that the aerosol concentrations and UV radiation are significantly correlated with ozone concentrations. The correlation coefficient between the aerosol optical depth （AOD） and the PM10 mass concentration is very high, with a maximum of 0.98, and the AOD and UV radiation/ozone is anti- correlated, with a correlation coefficient of-0.90. The analysis suggests that ozone productivity is significantly decreased due to the reduction of UV radiation. The noon-time ozone maximum is considerably depressed when AOD is 0.6, and is further decreased when AOD is up to 1.2 due to the reduction of ozone photochemical productivity. Because the occurring probability of aerosol optical depth for AOD550m≥0.6 and AOD340mm ≥1.0 is 47, and 55% respectively during the dry season （October, November, December, January）, this heavy aerosol condition explains the low ozone maximum that often occurs in the dry season over the Guangzhou region. The analysis also suggests that the value of single scattering albedo （SSA） is very sensitive to the aerosol radiative effect when the radiative and chemical models are applied, implying that the value of SSA needs to be carefully studied when the models are used in calculating ozone production.
基金supported by the National Key R&D Program of China(2017YFC0906800)the National Natural Science Foundation of China(21522507,21672166,21635006,21721005)
文摘The spatiotemporal expression of genes is sophisticatedly controlled through three main layers: transcriptional, translational and post-translational. Now increasing chemical modifications are discovered on genomic DNA, RNA and proteins. These modifications are recognized as additional layer of regulatory mechanisms in controlling gene expression that defines cell status. So far,more than 150 chemical modifications are identified in nucleic acids,and more than 400 discrete types of modifications are identified in proteins. How these modifications are interpreted are fundamental questions to our understanding of living organisms. The omics sciences of systems biology, including genomics, transcriptomics, proteomics, and metabolomics, have been in existence for decades. Due to the large numbers of modifications occurring in DNA, RNA and proteins with regulatory roles, we propose the modificaomics from the words of modification and omics. Modificaomics mainly refers to the comprehensive study of the modifications on DNA, RNA and proteins. In this review, we conceive modificaomics by introducing the discovered modifications in DNA, RNA and proteins as well as summarizing their biological functions. We hope the proposed modificaomics can provide a whole picture of modifications of these biopolymers and simulate the study of the functions of the modifications on DNA, RNA and proteins.
文摘Microbial oceanography is an emerging discipline resulted from the interaction,cross-fertilization and integration of life science and ocean science.Microbial oceanography integrates the principles of marine microbiology,microbial ecology and oceanography to study the role of microorganisms in the biogeochemical dynamics of natural marine ecosystems.The application of genomics tools to study marine microbes is resulting in rapid advancements in microbial oceanography that has important implications in global carbon cycle,climate change,and ecosystem function.Here we review the application of genomics and metagenomics in microbial oceanography and suggest future directions in microbial oceanography research.
