While many harmful algal blooms have been associated with increasing eutrophication, not all species respond similarly and the increasing challenge, especially for resource managers, is to determine which blooms are r...While many harmful algal blooms have been associated with increasing eutrophication, not all species respond similarly and the increasing challenge, especially for resource managers, is to determine which blooms are related to eutrophication and to understand why particular species proliferate under specific nutrient conditions. The overall goal of this brief review is to describe why nutrient loads are not changing in stoichiometric proportion to the "Redfield ratio", and why this has important consequences for algal growth. Many types of harmful algae appear to be able to thrive, and/or increase their production of toxins, when nutrient loads are not in proportion classically identified as Redfield ratios. Here we also describe some of the physiological mechanisms of different species to take up nutrients and to thrive under conditions of nutrient imbalance.展开更多
Since its initial description in 1964,research hastransformed spontaneous bacterial peritonitis (SBP)from a feared disease (with reported mortality of 90%)to a treatable complication of decompensated cirrhosis,albeit ...Since its initial description in 1964,research hastransformed spontaneous bacterial peritonitis (SBP)from a feared disease (with reported mortality of 90%)to a treatable complication of decompensated cirrhosis,albeit with steady prevalence and a high recurrencerate. Bacterial translocation,the key mechanism in thepathogenesis of SBP,is only possible because of theconcurrent failure of defensive mechanisms in cirrhosis.Variants of SBP should be treated. Leucocyte esterasereagent strips have managed to shorten the 'tap-to-shot' time,while future studies should look into theircombined use with ascitic fluid pH. Third generationcephalosporins are the antibiotic of choice becausethey have a number of advantages. Renal dysfunctionhas been shown to be an independent predictor ofmortality in patients with SBP. Albumin is felt to reducethe risk of renal impairment by improving effectiveintravascular volume,and by helping to bind pro-inflammatory molecules. Following a single episodeof SBP,patients should have long-term antibioticprophylaxis and be considered for liver transplantation.展开更多
The effects of varying nitrogen （N）： phosphorus （P） ratios on the growth and N-uptake and assimilation of the harmful dinoflagellates Prorocentrum minimum and Prorocentrum donghaiense were examined in turbidistat...The effects of varying nitrogen （N）： phosphorus （P） ratios on the growth and N-uptake and assimilation of the harmful dinoflagellates Prorocentrum minimum and Prorocentrum donghaiense were examined in turbidistat culture experiments. Algal cultures were supplied with media containing PO4^3- in various concentrations to obtain a wide range of N：P ratios. Experiments to determine rates of N uptake and assimilation of different N sources （NO^3-, NH4^＋, urea and glycine by P. minimum and NO3^-, NH4^＋ by P. donghaiense） were conducted using ^15-N tracer techniques at each N：P ratio. The growth rates suggested nutrient limitation at both high and low N：P ratios relative to the Redfield ratio. On a diel basis, the growth of both species was regulated by the light-dark cycle, which may be a result of regulation of both lightdependent growth and light-independent nutrient uptake. Maximum growth rates of both species always occurred at the beginning of light phase. In P-rich medium （low N：P ratio）, both species had higher N assimilation rates, suggesting N limitation. Low assimilation coefficients at high N：P ratios suggested P limitation of N uptake and assimilation. NO3 ^-and NH4^＋ contributed more than 90% of the total N uptake of P. minimum. Reduced N sources were more quickly assimilated than NO3^-. Highest average daily growth rates were recorded near an N：P ratio of 12 for both species. The N uptake rates of cultures at N：P ratios near Redfield ratio were more balanced with growth rates. The linkage between growth rates and N uptake/assimilation rates were conceptually described by the variation of cell N quota. The N：P ratios affect the N uptake and growth of Prorocentrum spp., and may regulate their bloom progression in eutrophic ecosystems.展开更多
Most important problems arising from industrial and technological developments are abundance and harmful effects of post-productive wastes. In most of the developed countries, these effects are avoided by orderly stor...Most important problems arising from industrial and technological developments are abundance and harmful effects of post-productive wastes. In most of the developed countries, these effects are avoided by orderly storing methods. Storing the wastes in random stacks in the site, and their effect on wide areas gives a rise to the risk of ground, air and under water pollution e.g., pollution of the surrounding environments. Therefore, in most engineering branches, effects and nature of harmful wastes are investigated and solution methods are developed. When structures made of concrete are to be demolished. Concrete recycling is an increasingly common method of disposing of the rubble. Concrete debris was once routinely shipped to landfills for disposal, but recycling has a number of benefits that have been made it a more attractive option in this age of greater environmental awareness, more environmental lows, and the desire to keep constant costs down. The purpose of this research is to study the effect of using demolished concrete as a reproducible coarse aggregate in fabricating normal and high strength concrete mixes. The effect of constituent materials in general and the recycled coarse aggregate in particular on the mechanical performance of the produced concrete mixes is investigated. The characteristics of using the by-pass product of cement industry as cementitious material in recycled concrete mixes with a percentage of 50% as a replacement of cement content is investigated too. Test results presented in this research leads to the promising use of crushed demolished concrete along with the by-pass product of cement as waste materials in producing concrete mixes as well as the optimistic results in enhancing the strength properties of plain concrete beside their benefits of the cost savings and reducing environmental impact.展开更多
High-efficiency recovery of Zn and Pb from silicon-rich zinc leaching residues is realized in a rotary kiln.Characterizations by means of XRD,SEM,EDS and ICP reveal that the leaching residue contains 12.4 wt.%SiO_(2),...High-efficiency recovery of Zn and Pb from silicon-rich zinc leaching residues is realized in a rotary kiln.Characterizations by means of XRD,SEM,EDS and ICP reveal that the leaching residue contains 12.4 wt.%SiO_(2),16.1 wt.%Zn,and 7.4 wt.%Pb.Thermodynamic analysis shows that metallic vapor of Zn and Pb can be easily generated from the zinc leaching residue at 1150-1250°C inside the rotary kiln.Viscosities and melting points of 13 slag compositions were analyzed and three slag compositions(47wt.%SiO_(2)-23wt.%CaO-30wt.%FeO,40wt.%SiO_(2)-28wt.%CaO-32wt.%FeO,and 40wt.%SiO_(2)-30wt.%CaO-30wt.%FeO)possessed the desirable physical properties,with the melting point and viscosity in the range of 1150-1280°C and 0.2-0.5 Pa·s,respectively.The industrial tests show that adopting the optimized slag composition can contribute to very high recovery rates of Zn and Pb(97.3%for Zn and 94.5%for Pb),corresponding to slags with very low average contents of Zn and Pb(0.51 wt.%Zn and 0.45 wt.%Pb).The National-Standard leaching tests of the water-quenched slags result in 1.82 mg/L Zn,~0.01 mg/L Cu,0.0004 mg/L As,~0.01 mg/L Cd,0.08 mg/L Pb,and~0.02 mg/L Hg in the leachate,verifying the detoxification of the zinc leaching residue at the same time.展开更多
For resource poor and HIV victim urban and pre-urban dwellers in developing countries, home garden is vital to enhance food and nutrient security. The availability of both ground and surface water in Bahir Dar city of...For resource poor and HIV victim urban and pre-urban dwellers in developing countries, home garden is vital to enhance food and nutrient security. The availability of both ground and surface water in Bahir Dar city of Ethiopia propels many poor families to produce vegetable and fruit crop for home consumption and income generation. Productivity of fruits and vegetables has been seriously affected due to lack of high yield with good quality varieties, poor knowledge of agronomic practices, poor water and fertilizer managements to exploit the full potential benefits of home garden to the area. To minimize those gaps, resource poor and HIV victim women headed households were selected and model home garden were established to demonstrate improved production practices. Subsequent trainings and experience sharing focused on the different techniques of vegetable and fruit crops production and management, methods of compost preparation and how to generate income from home garden were provided. The seeds of lettuce, Swiss chard, head cabbage, kale, carrot and improved banana sucker and coffee seedlings were supplied for each model home garden. Based on the training and experiences gained, different vegetable growing structures, such as old plastic containers, wooden boxes, vegetable growing shelves made from locally available materials and old used car tier, and ＂food always in the house＂ （FAITH） gardening techniques were established to maximize the potential of home garden both vertically and horizontally. Within one growing season, participants produced plenty leafy vegetable for home consumption and they started to generate income by supplying fresh vegetable products to the local market. Nowadays, participants have been sharing their knowledge and experiences to new neighboring gardeners through their model home gardens. Therefore, the respective stakeholders should provide continuous technical and financial support to strengthen the established model home garden as a training center to disseminate improved production techniques for Bahir Dar city residents for the future.展开更多
To study the impact of an artificial waterfall using reclaimed water on volatile organic compounds （VOCs） in air, air samples around the waterfall sight and over the CASS pond of a wastewater treatment plant were co...To study the impact of an artificial waterfall using reclaimed water on volatile organic compounds （VOCs） in air, air samples around the waterfall sight and over the CASS pond of a wastewater treatment plant were collected and VOCs were analyzed by MC-MS with USEPA Method TO-14. The total volatile organic compounds （TOVCs） concentration of a background sample is 2112 μg/m^3, and the sample over the CASS pond has a TVOC concentration of 1858μg/m^3. The TVOC concentrations of air samples within 10 m of the artificial waterfall are between 3216 μg/m^3 and 6362 μg/m^3, which are 1.52 - 3.0 times that of the background sample. The VOCs in air sample impacted by reclaimed water or waste water exhibit a relatively high proportion of toluene but low proportion of benzene. B/T/E/X （ Benzene/Toluene/Ethylbenzene/Xylene ） ratio of the air sample around the artificial water fall is（O. 36/11.78/1/1.10）. Health risk assessment （HRA） was done with the USEPA four-step approach. The result indicates that the artificial waterfall using reclaimed water indeed leads to the increase of human risk value. The total risk value of the sample around the waterfall is 2. 8 - 1.6 times that of the background sample. However, the total risk value of the air sample around the waterfall （2. 8 × 10^-6 ） for common people is still lower,compared to the acceptable public risk level（ 10^-5 ）. For occupational workers of the wastewater treatment plant, the sum of lifetime non-carcinogenic and carcinogenic risk values （ 1.26 × 10^ -5 ） is higher than that of the acceptable public risk level.展开更多
Purpose： To investigate the effects of estrogen G protein-coupled receptor 30 （GPR30） agonist G1 on hippocampal neuronal apoptosis and microglial polarization in rat traumatic brain injury （TBI）. Methods： Male S...Purpose： To investigate the effects of estrogen G protein-coupled receptor 30 （GPR30） agonist G1 on hippocampal neuronal apoptosis and microglial polarization in rat traumatic brain injury （TBI）. Methods： Male SD rats were randomly divided into sham group, TBI ＋ vehicle group, TBI ＋ G1 group. Experimental moderate TBI was induced using Feeney＇s weigh-drop method. GI （100μg/kg） or vehicle was intravenously injected from femoral vein at 30 rain post-injury. Rats were sacrificed at 24 h after injury for detection of neuronal apoptosis and microglia polarization. Neuronal apoptosis was assayed by immunofluorescent staining of active caspase-3. MI type microglia markers （iNOS and IL-113） and M2 type markers （Argl and IL-4） were examined by immunoblotting or ELLSA. Total protein level of Akt and phosphorylated Akt were assayed by immunoblotting. Results： G1 significantly reduced active caspase-3 positive neurons in hippocampus. Meanwhile G1 increased the ratio of Arg1/iNOS. IL-1β production was decreased but IL-4 was increased after G1 treatment. G1 treatment also increased the active form of Akt. Conclusions： GPR30 agonist GI inhibited neuronal apoptosis and favored microglia polarization to M2 type.展开更多
文摘While many harmful algal blooms have been associated with increasing eutrophication, not all species respond similarly and the increasing challenge, especially for resource managers, is to determine which blooms are related to eutrophication and to understand why particular species proliferate under specific nutrient conditions. The overall goal of this brief review is to describe why nutrient loads are not changing in stoichiometric proportion to the "Redfield ratio", and why this has important consequences for algal growth. Many types of harmful algae appear to be able to thrive, and/or increase their production of toxins, when nutrient loads are not in proportion classically identified as Redfield ratios. Here we also describe some of the physiological mechanisms of different species to take up nutrients and to thrive under conditions of nutrient imbalance.
文摘Since its initial description in 1964,research hastransformed spontaneous bacterial peritonitis (SBP)from a feared disease (with reported mortality of 90%)to a treatable complication of decompensated cirrhosis,albeit with steady prevalence and a high recurrencerate. Bacterial translocation,the key mechanism in thepathogenesis of SBP,is only possible because of theconcurrent failure of defensive mechanisms in cirrhosis.Variants of SBP should be treated. Leucocyte esterasereagent strips have managed to shorten the 'tap-to-shot' time,while future studies should look into theircombined use with ascitic fluid pH. Third generationcephalosporins are the antibiotic of choice becausethey have a number of advantages. Renal dysfunctionhas been shown to be an independent predictor ofmortality in patients with SBP. Albumin is felt to reducethe risk of renal impairment by improving effectiveintravascular volume,and by helping to bind pro-inflammatory molecules. Following a single episodeof SBP,patients should have long-term antibioticprophylaxis and be considered for liver transplantation.
基金supported by the University of Maryland Center for Environmental Science (UMCES), Horn Point Laboratory. This is UMCES contribution number 4503
文摘The effects of varying nitrogen （N）： phosphorus （P） ratios on the growth and N-uptake and assimilation of the harmful dinoflagellates Prorocentrum minimum and Prorocentrum donghaiense were examined in turbidistat culture experiments. Algal cultures were supplied with media containing PO4^3- in various concentrations to obtain a wide range of N：P ratios. Experiments to determine rates of N uptake and assimilation of different N sources （NO^3-, NH4^＋, urea and glycine by P. minimum and NO3^-, NH4^＋ by P. donghaiense） were conducted using ^15-N tracer techniques at each N：P ratio. The growth rates suggested nutrient limitation at both high and low N：P ratios relative to the Redfield ratio. On a diel basis, the growth of both species was regulated by the light-dark cycle, which may be a result of regulation of both lightdependent growth and light-independent nutrient uptake. Maximum growth rates of both species always occurred at the beginning of light phase. In P-rich medium （low N：P ratio）, both species had higher N assimilation rates, suggesting N limitation. Low assimilation coefficients at high N：P ratios suggested P limitation of N uptake and assimilation. NO3 ^-and NH4^＋ contributed more than 90% of the total N uptake of P. minimum. Reduced N sources were more quickly assimilated than NO3^-. Highest average daily growth rates were recorded near an N：P ratio of 12 for both species. The N uptake rates of cultures at N：P ratios near Redfield ratio were more balanced with growth rates. The linkage between growth rates and N uptake/assimilation rates were conceptually described by the variation of cell N quota. The N：P ratios affect the N uptake and growth of Prorocentrum spp., and may regulate their bloom progression in eutrophic ecosystems.
文摘Most important problems arising from industrial and technological developments are abundance and harmful effects of post-productive wastes. In most of the developed countries, these effects are avoided by orderly storing methods. Storing the wastes in random stacks in the site, and their effect on wide areas gives a rise to the risk of ground, air and under water pollution e.g., pollution of the surrounding environments. Therefore, in most engineering branches, effects and nature of harmful wastes are investigated and solution methods are developed. When structures made of concrete are to be demolished. Concrete recycling is an increasingly common method of disposing of the rubble. Concrete debris was once routinely shipped to landfills for disposal, but recycling has a number of benefits that have been made it a more attractive option in this age of greater environmental awareness, more environmental lows, and the desire to keep constant costs down. The purpose of this research is to study the effect of using demolished concrete as a reproducible coarse aggregate in fabricating normal and high strength concrete mixes. The effect of constituent materials in general and the recycled coarse aggregate in particular on the mechanical performance of the produced concrete mixes is investigated. The characteristics of using the by-pass product of cement industry as cementitious material in recycled concrete mixes with a percentage of 50% as a replacement of cement content is investigated too. Test results presented in this research leads to the promising use of crushed demolished concrete along with the by-pass product of cement as waste materials in producing concrete mixes as well as the optimistic results in enhancing the strength properties of plain concrete beside their benefits of the cost savings and reducing environmental impact.
基金the funding support from the National Natural Science Foundation of China (Nos. 51804221, 51874101)the National Key R&D Program of China (No. 2019YFF0217102)the China Postdoctoral Science Foundation (Nos. 2018M642906, 2019T120684)
文摘High-efficiency recovery of Zn and Pb from silicon-rich zinc leaching residues is realized in a rotary kiln.Characterizations by means of XRD,SEM,EDS and ICP reveal that the leaching residue contains 12.4 wt.%SiO_(2),16.1 wt.%Zn,and 7.4 wt.%Pb.Thermodynamic analysis shows that metallic vapor of Zn and Pb can be easily generated from the zinc leaching residue at 1150-1250°C inside the rotary kiln.Viscosities and melting points of 13 slag compositions were analyzed and three slag compositions(47wt.%SiO_(2)-23wt.%CaO-30wt.%FeO,40wt.%SiO_(2)-28wt.%CaO-32wt.%FeO,and 40wt.%SiO_(2)-30wt.%CaO-30wt.%FeO)possessed the desirable physical properties,with the melting point and viscosity in the range of 1150-1280°C and 0.2-0.5 Pa·s,respectively.The industrial tests show that adopting the optimized slag composition can contribute to very high recovery rates of Zn and Pb(97.3%for Zn and 94.5%for Pb),corresponding to slags with very low average contents of Zn and Pb(0.51 wt.%Zn and 0.45 wt.%Pb).The National-Standard leaching tests of the water-quenched slags result in 1.82 mg/L Zn,~0.01 mg/L Cu,0.0004 mg/L As,~0.01 mg/L Cd,0.08 mg/L Pb,and~0.02 mg/L Hg in the leachate,verifying the detoxification of the zinc leaching residue at the same time.
文摘For resource poor and HIV victim urban and pre-urban dwellers in developing countries, home garden is vital to enhance food and nutrient security. The availability of both ground and surface water in Bahir Dar city of Ethiopia propels many poor families to produce vegetable and fruit crop for home consumption and income generation. Productivity of fruits and vegetables has been seriously affected due to lack of high yield with good quality varieties, poor knowledge of agronomic practices, poor water and fertilizer managements to exploit the full potential benefits of home garden to the area. To minimize those gaps, resource poor and HIV victim women headed households were selected and model home garden were established to demonstrate improved production practices. Subsequent trainings and experience sharing focused on the different techniques of vegetable and fruit crops production and management, methods of compost preparation and how to generate income from home garden were provided. The seeds of lettuce, Swiss chard, head cabbage, kale, carrot and improved banana sucker and coffee seedlings were supplied for each model home garden. Based on the training and experiences gained, different vegetable growing structures, such as old plastic containers, wooden boxes, vegetable growing shelves made from locally available materials and old used car tier, and ＂food always in the house＂ （FAITH） gardening techniques were established to maximize the potential of home garden both vertically and horizontally. Within one growing season, participants produced plenty leafy vegetable for home consumption and they started to generate income by supplying fresh vegetable products to the local market. Nowadays, participants have been sharing their knowledge and experiences to new neighboring gardeners through their model home gardens. Therefore, the respective stakeholders should provide continuous technical and financial support to strengthen the established model home garden as a training center to disseminate improved production techniques for Bahir Dar city residents for the future.
基金the Military Scientific Research Project (Grant No.c8630)
文摘To study the impact of an artificial waterfall using reclaimed water on volatile organic compounds （VOCs） in air, air samples around the waterfall sight and over the CASS pond of a wastewater treatment plant were collected and VOCs were analyzed by MC-MS with USEPA Method TO-14. The total volatile organic compounds （TOVCs） concentration of a background sample is 2112 μg/m^3, and the sample over the CASS pond has a TVOC concentration of 1858μg/m^3. The TVOC concentrations of air samples within 10 m of the artificial waterfall are between 3216 μg/m^3 and 6362 μg/m^3, which are 1.52 - 3.0 times that of the background sample. The VOCs in air sample impacted by reclaimed water or waste water exhibit a relatively high proportion of toluene but low proportion of benzene. B/T/E/X （ Benzene/Toluene/Ethylbenzene/Xylene ） ratio of the air sample around the artificial water fall is（O. 36/11.78/1/1.10）. Health risk assessment （HRA） was done with the USEPA four-step approach. The result indicates that the artificial waterfall using reclaimed water indeed leads to the increase of human risk value. The total risk value of the sample around the waterfall is 2. 8 - 1.6 times that of the background sample. However, the total risk value of the air sample around the waterfall （2. 8 × 10^-6 ） for common people is still lower,compared to the acceptable public risk level（ 10^-5 ）. For occupational workers of the wastewater treatment plant, the sum of lifetime non-carcinogenic and carcinogenic risk values （ 1.26 × 10^ -5 ） is higher than that of the acceptable public risk level.
基金This work was supported by Natural Science Foundation of China （NSFC 81470599）.
文摘Purpose： To investigate the effects of estrogen G protein-coupled receptor 30 （GPR30） agonist G1 on hippocampal neuronal apoptosis and microglial polarization in rat traumatic brain injury （TBI）. Methods： Male SD rats were randomly divided into sham group, TBI ＋ vehicle group, TBI ＋ G1 group. Experimental moderate TBI was induced using Feeney＇s weigh-drop method. GI （100μg/kg） or vehicle was intravenously injected from femoral vein at 30 rain post-injury. Rats were sacrificed at 24 h after injury for detection of neuronal apoptosis and microglia polarization. Neuronal apoptosis was assayed by immunofluorescent staining of active caspase-3. MI type microglia markers （iNOS and IL-113） and M2 type markers （Argl and IL-4） were examined by immunoblotting or ELLSA. Total protein level of Akt and phosphorylated Akt were assayed by immunoblotting. Results： G1 significantly reduced active caspase-3 positive neurons in hippocampus. Meanwhile G1 increased the ratio of Arg1/iNOS. IL-1β production was decreased but IL-4 was increased after G1 treatment. G1 treatment also increased the active form of Akt. Conclusions： GPR30 agonist GI inhibited neuronal apoptosis and favored microglia polarization to M2 type.
