Wastewater treatment is a process that is vital to protecting both the environment and human health. At present, the most cost-effective way of treating wastewater is with biological treatment processes such as the ac...Wastewater treatment is a process that is vital to protecting both the environment and human health. At present, the most cost-effective way of treating wastewater is with biological treatment processes such as the activated sludge process, despite their long operating times. However, population increases have created a demand for more efficient means of wastewater treatment, Fluidization has been demonstrated to in- crease the efficiency of many processes in chemical and biochemical engineering, but it has not been widely used in large-scale wastewater treatment. At the University of Western Ontario, the circulating fluidized-bed bioreactor （CFBBR） was developed for treating wastewater. In this process, carrier particles develop a biofilm composed of bacteria and other microbes. The excellent mixing and mass transfer characteristics inherent to fluidization make this process very effective at treating both municipal and industrial wastewater. Studies of lab- and pilot-scale systems showed that the CFBBR can remove over 90% of the influent organic matter and 80% of the nitrogen, and produces less than one-third as much biological sludge as the activated sludge process. Due to its high efficiency, the CFBBR can also be used to treat wastewaters with high organic solid concentrations, which are more difficult to treat with conventional methods because they require longer residence times; the CFBBR can also be used to reduce the system size and footprint. In addition, it is much better at handling and recovering from dynamic loadings （i.e., varying influent volume and concentrations） than current systems. Overall, the CFBBR has been shown to be a very effective means of treating wastewa- ter, and to be capable of treating larger volumes of wastewater using a smaller reactor volume and a shorter residence time. In addition, its compact design holds potential for more geographically localized and isolat- ed wastewater treatment systems.展开更多
Summary： The contribution of particles to cardiovascular mortality and morbidity has been enlightened by epidemiologic and experimental studies. However, adverse biological effects of the particles with different siz...Summary： The contribution of particles to cardiovascular mortality and morbidity has been enlightened by epidemiologic and experimental studies. However, adverse biological effects of the particles with different sizes on cardiovascular cells have not been well recognized. In this study, sub-cultured human umbilical vein endothelial cells （HUVECs） were exposed to increasing concentrations of pure quartz particles （DQ） of three sizes （DQPM1, 〈1 μm; DQPM3-5, 3-5 μm; DQPM5, 5 μm） and carbon black particles of two sizes （CB0.1, 〈0.1 μm; CB 1, 〈 1 μm） for 24 h. Cytotoxicity was estimated by measuring the activity of lactate dehydrogenase （LDH） and cell viability. Nitric oxide （NO） generation and cyto- kines （TNF-α and IL-1β） releases were analyzed by using NO assay and enzyme-linked immunoabsorbent assay （ELISA）, respectively. It was found that both particles induced adverse biological effects on HUVECs in a dose-dependent manner. The size of particle directly influenced the biological activity. For quartz, the smaller particles induced stronger cytotoxicity and higher levels of cytokine responses than those particles of big size. For carbon black particles, CB0.1 was more capable of inducing adverse responses on HUVECs than CB 1 only at lower particle concentrations, in contrast to those at higher concentrations. Meanwhile, our data also revealed that quartz particles performed stronger cell damage and produced higher levels of TNF-α than carbon black particles, even if particles size was similar. In conclusion, particle size as well as particle composition should be both considered in assessing vascular endothelial cells injury and inflammation responses induced by particles.展开更多
Multifunctional fluorescent magnetic nanoparticles （Fe3O4@SiO2-PLLA-RhB/FA） with cell recognition ability were synthesized through conjugation of magnetic nanoparticles with folic acid （FA） and Rhodamine B. To ver...Multifunctional fluorescent magnetic nanoparticles （Fe3O4@SiO2-PLLA-RhB/FA） with cell recognition ability were synthesized through conjugation of magnetic nanoparticles with folic acid （FA） and Rhodamine B. To verity their potential biomedical applications, biocompatibility as well as cell imaging applications of the multifunctional nanoparticles were further investigated. Results showed that these fluorescent magnetic nanoparticles are well bio- compatible with NIH-3T3 cells and HeLa cells. More importantly, these nanoparticles could be selectively taken up by HeLa cells （FA receptor positive） as evidenced by laser scanning confocal microscopy, suggesting their potential for biological imaging applications. Given their excellent biocompatibility and multifunctional characteristics, weexpect that the fluorescent magnetic nanoparticles could be promising for various biomedical applications.展开更多
The fluorescent dye 4′,6-diamidino-2-phenylindole (DAPI) has been widely used to stain microorganisms in various environment media. We applied DAPI fluorescence enumeration to airborne microorganisms and found that n...The fluorescent dye 4′,6-diamidino-2-phenylindole (DAPI) has been widely used to stain microorganisms in various environment media. We applied DAPI fluorescence enumeration to airborne microorganisms and found that non-biological particles, including organic compounds, minerals, and soot, were also visible upon exposure to UV excitation under fluorescence microscope. Using laboratory-prepared biological particles as the control, we investigated the feasibility of identifying both biological and non-biological particles in the same sample with DAPI staining. We prepared biological (bacterial, fungi, and plant detritus) and non-biological (biochar, soot, mineral, metal, fly ash, salt) particles in the laboratory and enumerated the particles and their mixture with DAPI. We found that mineral particles were transparent, and biochar, soot, metals and fly ash particles were black under a filter set at excitation 350/50 nm and emission 460/50 nm bandpass (DAPI-BP), while biological particles were blue, as expected. Particles of the water-soluble salts NaCl and (NH_(4))_(2)SO_(4) were yellow under a filter set at excitation 340–380 nm and emission 425 nm long pass (DAPI-LP). Case studies with samples of dustfall, atmospheric aerosols and surface soils could allow for the quantification of the relative number of different types of particles and particles with organic matter or salt coating as well. Fluorescence enumeration with DAPI stain is thus able to identify the co-existence of biological and non-biological particles in the air, at least to the extent of those examined in this study.展开更多
The nutrient-rich Pacific Ocean seawater that flows through the Bering Strait into the Chukchi Sea is generally considered to be the most important source of nutrients to the Arctic euphotic zone.The inflow is charact...The nutrient-rich Pacific Ocean seawater that flows through the Bering Strait into the Chukchi Sea is generally considered to be the most important source of nutrients to the Arctic euphotic zone.The inflow is characterized by nitrogen deficit and low nitrate/phosphate(N/P)ratios;this is ascribed to sedimentary denitrification on the Chukchi shelf by preoccupant opinions.However,the Chukchi Sea also has high primary production,which raises the question of whether the biological pump may also significantly modulate nutrient properties of the throughflow.Here,we show that nitrate concentrations of the Pacific inflow gradually decrease northward in association with notable biological utilization.The phytoplankton N/P uptake ratio was 8.8±2.27,higher than the N/P ratio of Pacific inflow water(5-6).This uptake ratio,in combination with efficient vertical nitrogen export,serves to preferentially remove nitrogen(relative to phosphorus)from upper waters,thereby further intensifying the Arctic nitrogen deficit.Accordingly,as large as about 111.7×10^(9)mol N yr^(−1)of nitrate was extra consumed,according to the real N/P uptake ratio rather than the ratio of the Pacific inflow,which may be as great as half the nitrogen loss ascribed to sedimentary denitrification.Our findings suggest that besides sedimentary denitrification,biological disproportionate utilization of nutrients in the Chukchi Sea upper water is another important contributor to the nitrogen limitation and excess phosphorus in the upper Arctic Ocean.In the rapid Arctic change era,the predicted reinforced biological carbon pump could further impact the nutrient dynamics and biogeochemical process of the Arctic Ocean.展开更多
文摘Wastewater treatment is a process that is vital to protecting both the environment and human health. At present, the most cost-effective way of treating wastewater is with biological treatment processes such as the activated sludge process, despite their long operating times. However, population increases have created a demand for more efficient means of wastewater treatment, Fluidization has been demonstrated to in- crease the efficiency of many processes in chemical and biochemical engineering, but it has not been widely used in large-scale wastewater treatment. At the University of Western Ontario, the circulating fluidized-bed bioreactor （CFBBR） was developed for treating wastewater. In this process, carrier particles develop a biofilm composed of bacteria and other microbes. The excellent mixing and mass transfer characteristics inherent to fluidization make this process very effective at treating both municipal and industrial wastewater. Studies of lab- and pilot-scale systems showed that the CFBBR can remove over 90% of the influent organic matter and 80% of the nitrogen, and produces less than one-third as much biological sludge as the activated sludge process. Due to its high efficiency, the CFBBR can also be used to treat wastewaters with high organic solid concentrations, which are more difficult to treat with conventional methods because they require longer residence times; the CFBBR can also be used to reduce the system size and footprint. In addition, it is much better at handling and recovering from dynamic loadings （i.e., varying influent volume and concentrations） than current systems. Overall, the CFBBR has been shown to be a very effective means of treating wastewa- ter, and to be capable of treating larger volumes of wastewater using a smaller reactor volume and a shorter residence time. In addition, its compact design holds potential for more geographically localized and isolat- ed wastewater treatment systems.
基金supported by grants from the National Basic Research Program of China(No.2011CB503804)the National Natural Science Foundation of China(No.81372967)
文摘Summary： The contribution of particles to cardiovascular mortality and morbidity has been enlightened by epidemiologic and experimental studies. However, adverse biological effects of the particles with different sizes on cardiovascular cells have not been well recognized. In this study, sub-cultured human umbilical vein endothelial cells （HUVECs） were exposed to increasing concentrations of pure quartz particles （DQ） of three sizes （DQPM1, 〈1 μm; DQPM3-5, 3-5 μm; DQPM5, 5 μm） and carbon black particles of two sizes （CB0.1, 〈0.1 μm; CB 1, 〈 1 μm） for 24 h. Cytotoxicity was estimated by measuring the activity of lactate dehydrogenase （LDH） and cell viability. Nitric oxide （NO） generation and cyto- kines （TNF-α and IL-1β） releases were analyzed by using NO assay and enzyme-linked immunoabsorbent assay （ELISA）, respectively. It was found that both particles induced adverse biological effects on HUVECs in a dose-dependent manner. The size of particle directly influenced the biological activity. For quartz, the smaller particles induced stronger cytotoxicity and higher levels of cytokine responses than those particles of big size. For carbon black particles, CB0.1 was more capable of inducing adverse responses on HUVECs than CB 1 only at lower particle concentrations, in contrast to those at higher concentrations. Meanwhile, our data also revealed that quartz particles performed stronger cell damage and produced higher levels of TNF-α than carbon black particles, even if particles size was similar. In conclusion, particle size as well as particle composition should be both considered in assessing vascular endothelial cells injury and inflammation responses induced by particles.
基金The authors gratefully acknowledge the financial support of the National Natural Science Foundation of China （Nos. 21374053, 51573086）.
文摘Multifunctional fluorescent magnetic nanoparticles （Fe3O4@SiO2-PLLA-RhB/FA） with cell recognition ability were synthesized through conjugation of magnetic nanoparticles with folic acid （FA） and Rhodamine B. To verity their potential biomedical applications, biocompatibility as well as cell imaging applications of the multifunctional nanoparticles were further investigated. Results showed that these fluorescent magnetic nanoparticles are well bio- compatible with NIH-3T3 cells and HeLa cells. More importantly, these nanoparticles could be selectively taken up by HeLa cells （FA receptor positive） as evidenced by laser scanning confocal microscopy, suggesting their potential for biological imaging applications. Given their excellent biocompatibility and multifunctional characteristics, weexpect that the fluorescent magnetic nanoparticles could be promising for various biomedical applications.
基金supports from the Open Fund of Hubei Key Laboratory of Mine Environmental Pollution Control and Remediation(grant No.2014104)the Research Project of Hubei Provincial Department of Education(grant No.D20184502)the National Natural Science Foundation of China(grant No.42107088).
文摘The fluorescent dye 4′,6-diamidino-2-phenylindole (DAPI) has been widely used to stain microorganisms in various environment media. We applied DAPI fluorescence enumeration to airborne microorganisms and found that non-biological particles, including organic compounds, minerals, and soot, were also visible upon exposure to UV excitation under fluorescence microscope. Using laboratory-prepared biological particles as the control, we investigated the feasibility of identifying both biological and non-biological particles in the same sample with DAPI staining. We prepared biological (bacterial, fungi, and plant detritus) and non-biological (biochar, soot, mineral, metal, fly ash, salt) particles in the laboratory and enumerated the particles and their mixture with DAPI. We found that mineral particles were transparent, and biochar, soot, metals and fly ash particles were black under a filter set at excitation 350/50 nm and emission 460/50 nm bandpass (DAPI-BP), while biological particles were blue, as expected. Particles of the water-soluble salts NaCl and (NH_(4))_(2)SO_(4) were yellow under a filter set at excitation 340–380 nm and emission 425 nm long pass (DAPI-LP). Case studies with samples of dustfall, atmospheric aerosols and surface soils could allow for the quantification of the relative number of different types of particles and particles with organic matter or salt coating as well. Fluorescence enumeration with DAPI stain is thus able to identify the co-existence of biological and non-biological particles in the air, at least to the extent of those examined in this study.
基金supported by the National Natural Science Foundation of China(Grant Nos.41003036&41941013)the Chinese National Arctic Research Expedition Project(CHINARE)+1 种基金the Cai Yuanpei Programthe ICAR Project(China Scholarship Council)。
文摘The nutrient-rich Pacific Ocean seawater that flows through the Bering Strait into the Chukchi Sea is generally considered to be the most important source of nutrients to the Arctic euphotic zone.The inflow is characterized by nitrogen deficit and low nitrate/phosphate(N/P)ratios;this is ascribed to sedimentary denitrification on the Chukchi shelf by preoccupant opinions.However,the Chukchi Sea also has high primary production,which raises the question of whether the biological pump may also significantly modulate nutrient properties of the throughflow.Here,we show that nitrate concentrations of the Pacific inflow gradually decrease northward in association with notable biological utilization.The phytoplankton N/P uptake ratio was 8.8±2.27,higher than the N/P ratio of Pacific inflow water(5-6).This uptake ratio,in combination with efficient vertical nitrogen export,serves to preferentially remove nitrogen(relative to phosphorus)from upper waters,thereby further intensifying the Arctic nitrogen deficit.Accordingly,as large as about 111.7×10^(9)mol N yr^(−1)of nitrate was extra consumed,according to the real N/P uptake ratio rather than the ratio of the Pacific inflow,which may be as great as half the nitrogen loss ascribed to sedimentary denitrification.Our findings suggest that besides sedimentary denitrification,biological disproportionate utilization of nutrients in the Chukchi Sea upper water is another important contributor to the nitrogen limitation and excess phosphorus in the upper Arctic Ocean.In the rapid Arctic change era,the predicted reinforced biological carbon pump could further impact the nutrient dynamics and biogeochemical process of the Arctic Ocean.
