Assessing the resilience of rice varieties against bioterrorism agents is critical to safeguarding food security.This study evaluated Food and Drug Administration-approved and recognized as safe metallic oxide nanopar...Assessing the resilience of rice varieties against bioterrorism agents is critical to safeguarding food security.This study evaluated Food and Drug Administration-approved and recognized as safe metallic oxide nanoparticles(NPs)of zinc oxide(ZnO)and magnesium oxide(MgO)as protective strategies to reduce susceptibility in imported rice varieties to a biothreat model,Escherichia coli.Two types of rice(brown and white)from four countries(USA,Mexico,India,and Thailand)were treated with 60 mg/L NPs or their ionic forms and sterilized before inoculation.The treatments were analyzed for nutritional profiles,heavy metal content,and pathogen susceptibility.Rice organic compositions were characterized by Fourier transform infrared spectroscopy,and metal were contents quantified using inductively coupled plasma optical emission spectroscopy.Pathogenic response was monitored using ultraviolet mass spectrophotometry.The findings revealed that nutrient-rich varieties like brown rice from Mexico displayed reduced susceptibility to E.coli compared with white rice from India,which showed the highest susceptibility.NP fortification demonstrated significant antimicrobial efficacy,particularly with ZnO and MgO NPs,which were more effective than their ionic counterparts in inhibiting bacterial growth.Results showed that ZnO and MgO NP treatments reduced E.coli growth by 72%and 68%,respectively,compared with untreated controls.Brown rice from Mexican treated with MgO NPs exhibited the lowest optical density at 600 nm(OD6000.01),indicating significantly enhanced resistance to bacterial proliferation.This research underscores the potential of nano-fortification not only to improve pathogen resilience in rice but also to maintain its nutritional integrity.This study provides a foundational framework for enhancing food safety against bioterrorism agents and supports the development of resilient agricultural practices.展开更多
The Regional Climate Model(RegCM)proves valuable for climate analysis and has been applied to a wide range of climate change aspects and other environmental issues at a regional scale.The model also demonstrated succe...The Regional Climate Model(RegCM)proves valuable for climate analysis and has been applied to a wide range of climate change aspects and other environmental issues at a regional scale.The model also demonstrated success in diverse areas of urban research,including urban heat island studies,extreme climate events analysis,assessing urban resilience,and evaluating urbanization impacts on climate and air quality.Recently,more studies have been conducted in utilizing RegCM to address climate change in cities,due to its enhanced ability over the years to capture meteorological phenomena at city scales.However,there are many challenges associated with its implementation in meso-scale research,which are attributed to various shortcomings and thus create room for further improvement in the model.This paper presents a comprehensive overview of the evolution of the RegCM over the years and its customisation across various parameters,demonstrating its versatility in urban climate studies and underscoring the model’s pivotal role in addressing multifaceted challenges in urban environments.By addressing these aspects,the paper offers valuable insights and recommendations for researchers seeking to enhance the accuracy and efficacy of urban climate simulations using the RegCM system,thereby contributing to the advancement of urban climate science and sustainability.展开更多
Field experiments were conducted from 2012 to 2015 in an arid region of Northwest China to investigate the effects of planting density on plant growth, yield, and water use efficiency（WUE） of maize for seed producti...Field experiments were conducted from 2012 to 2015 in an arid region of Northwest China to investigate the effects of planting density on plant growth, yield, and water use efficiency（WUE） of maize for seed production. Five planting densities of 6.75, 8.25, 9.75, 11.25 and 12.75 plants/m^2 were conducted in 2012, and a planting density of 14.25 plants/m^2 was added from 2013 to 2015. Through comparison with the Aqua Crop yield model, a modified model was developed to estimate the biomass accumulation and yield under different planting densities using adjustment coefficient for normalized biomass water productivity and harvest index. It was found that the modified yield model had a better performance and could generate results with higher determination coefficient and lower error. The results indicated that higher planting density increased the leaf area index and biomass accumulation, but decreased the biomass accumulation per plant. The total yield increased rapidly as planting density increased to 11.25 plants/m^2, but only a slight increase was observed when the density was greater than 11.25 plants/m^2. The WUE also reached the maximum when planting density was 11.25 plants/m^2, which was the recommended planting density of maize for seed production in Northwest China.展开更多
Currently,the most cost-effective and efficient method for phosphorus(P)removal from wastewater is enhanced biological P removal(EPBR)via polyphosphate-accumulating organisms(PAOs).This study integrates a literature r...Currently,the most cost-effective and efficient method for phosphorus(P)removal from wastewater is enhanced biological P removal(EPBR)via polyphosphate-accumulating organisms(PAOs).This study integrates a literature review with genomic analysis to uncover the phylogenetic and metabolic diversity of the relevant PAOs for wastewater treatment.The findings highlight significant differences in the metabolic capabilities of PAOs relevant to wastewater treatment.Notably,Candidatus Dechloromonas and Candidatus Accumulibacter can synthesize polyhydroxyalkanoates,possess specific enzymes for ATP production from polyphosphate,and have electrochemical transporters for acetate and C4-dicarboxylates.In contrast,Tetrasphaera,Candidatus Phosphoribacter,Knoellia,and Phycicoccus possess PolyP-glucokinase and electrochemical transporters for sugars/amino acids.Additionally,this review explores various detection methods for polyphosphate and PAOs in activated sludge wastewater treatment plants.Notably,FISH-Raman spectroscopy emerges as one of the most advanced detection techniques.Overall,this review provides critical insights into PAO research,underscoring the need for enhanced strategies in biological phosphorus removal.展开更多
Fruits,vegetables,and dairy products are typically the primary sources of household food waste.Currently,anaerobic digestion is the most used bioprocess for the treatment of food waste with concomitant generation of b...Fruits,vegetables,and dairy products are typically the primary sources of household food waste.Currently,anaerobic digestion is the most used bioprocess for the treatment of food waste with concomitant generation of biogas.However,to achieve a circular carbon economy,the organics in food waste should be converted to new chemicals with higher value than energy.Here we demonstrate the feasibility of medium-chain carboxylic acid(MCCA)production from expired dairy and beverage waste via a chain elongation platform mediated by lactate.In a two-stage fermentation process,the first stage with optimized operational conditions,including varying temperatures and organic loading rates,transformed expired dairy and beverage waste into lactate at a concentration higher than 900 mM C at 43℃.This lactate was then used to produce>500 mM C caproate and>300 mM C butyrate via microbial chain elongation.Predominantly,lactate-producing microbes such as Lactobacillus and Lacticaseibacillus were regulated by temperature and could be highly enriched under mesophilic conditions in the firststage reactor.In the second-stage chain elongation reactor,the dominating microbes were primarily from the genera Megasphaera and Caproiciproducens,shaped by varying feed and inoculum sources.Cooccurrence network analysis revealed positive correlations among species from the genera Caproiciproducens,Ruminococcus,and CAG-352,as well as Megasphaera,Bacteroides,and Solobacterium,indicating strong microbial interactions that enhance caproate production.These findings suggest that producing MCCAs from expired dairy and beverage waste via lactate-mediated chain elongation is a viable method for sustainable waste management and could serve as a chemical production platform in the context of building a circular bioeconomy.展开更多
In this article, the authors propose the production of ethanol from cellulose as an alternative to oil. Cellulosic-ethanol will reduce greenhouse gas emissions, and provide a means to prevent forest fires. This liquid...In this article, the authors propose the production of ethanol from cellulose as an alternative to oil. Cellulosic-ethanol will reduce greenhouse gas emissions, and provide a means to prevent forest fires. This liquid dense fuel was selected because it： （1） easily transported and dispensed as a fuel; （2） can be handled by the existing fuel distribution infrastructure; and （3） unlike its commercial competitor, Me-OH （Methanol）, Et-OH （Ethanol）, is edible, thus being biodegradable and nontoxic. Forest residue ethanol is cheaper to produce and more environmentally friendly than other forms of ethanol fuel. Furthermore, forests would have less available ground fuel for fires. The potential decline of forest fires would then reduce the carbon footprint attributed directly to forest fires. In combination with ethanol fuel combustion, carbon emissions can be reduced by more than 70% compared to gasoline combustion. We used GREET （Greenhouse gases, Regulated Emissions, and Energy use in Transportation） software to assess the life cycles of different fuel pathways. In conclusion, cellulosic ethanol fuel is clearly an answer to decrease dependency on current oil imports and prevent forest fires.展开更多
Alginates are naturally occurring components of organic matter in natural soil whose effects on nanoparticle （NP） toxicity to plants is not well understood. In the present study, corn plants were grown for one month...Alginates are naturally occurring components of organic matter in natural soil whose effects on nanoparticle （NP） toxicity to plants is not well understood. In the present study, corn plants were grown for one month in soil spiked with 400 mg/kg CeO2 NPs with various alginate concentrations. After one month of growth in the NPs impacted soil, plants were harvested and analyzed for Ce and mineral element concentrations. Chlorophyll concentration and heat shock protein 70, used as biomarkers for oxidative stress, were also evaluated. Results showed that, compared to CeO2 NPs treatment, alginate at 10, 50, and 100 mg/kg increased Ce concentration in roots by approximately 46%, 38%, and 29% and by 115%, 45%, and 56% in shoots, respectively. CeO 2 NPs without alginate increased Mn accumulation in roots by 34% compared to control. CeO2 NPs with low and medium alginate increased Mn by ca. 92% respect to NPs without alginate and by ca. 155% respect to control. CeO2 NPs without/with alginate significantly increased accumulation of Fe and Al in roots. In addition, alginate at 50 mg/kg increased Zn accumulation in roots by 52% compared to control. In shoots, K increased at all NP treatments but the accumulation of other elements was not affected. Alginate enlarged the impact of CeO2 NPs to corn plants by reducing chlorophyll a content and triggering overexpression of heat shock protein 70.展开更多
Microbial aggregates of different sizes in aerobic granular sludge(AGS)systems have been shown to exhibit distinct microbial community compositions.However,studies comparing the microbial activities of different-sized...Microbial aggregates of different sizes in aerobic granular sludge(AGS)systems have been shown to exhibit distinct microbial community compositions.However,studies comparing the microbial activities of different-sized aggregates in AGS systems remain limited.In this study,genome-resolved metatranscriptomics was used to investigate microbial activity patterns within differently sized aggregates in a full-scale AGS plant.Our analysis revealed a weak correlation between the relative abundance of metagenome-assembled genomes(MAGs)and their transcriptomic activity,indicating that microbial abundance does not directly correspond to metabolic activity within the system.Flocculent sludge(FL;<0.2 mm)predominantly featured active nitrifiers and fermentative polyphosphate-accumulating organisms(PAOs)from Candidatus Phosphoribacter,while small granules(SG;0.2e1.0 mm)and large granules(LG;>1.0 mm)hosted more metabolically active PAOs affiliated with Ca.Accumulibacter.Differential gene expression analysis further supported these findings,demonstrating significantly higher expression levels of key phosphorus uptake genes associated with Ca.Accumulibacter in granular sludge(SG and LG)compared to flocculent sludge.Conversely,Ca.Phosphoribacter showed higher expression of these genes in the FL fraction.This study highlights distinct functional roles and metabolic activities of crucial microbial communities depending on aggregate size within AGS systems,offering new insights into optimizing wastewater treatment processes.展开更多
Numerous natural and industrial processes entail the spontaneous entrapment of gas/air as rough/patterned surfaces are submerged under water.As the wetting transitions ensue,the gas diffuses into the water leading to ...Numerous natural and industrial processes entail the spontaneous entrapment of gas/air as rough/patterned surfaces are submerged under water.As the wetting transitions ensue,the gas diffuses into the water leading to the fully water-filled state.However,the standard models forwetting do not accountfor the microtexture’s topography on collective wetting transitions.In other words,it is not clear whether the lifetime of n cavities arranged in a one-dimensional(I-D)line or a two-dimensional(II-D)(circular or square)lattice would be the same or not as a single 0-D cavity.In response,we tracked the time-dependentfates of gas pockets trapped in I-D and II-D lattices and compared them with wetting transitions in commensurate 0-D cavities.Interestingly,the collective wetting transitions in the I-D and the II-D arrays had a directionality such thatthe gas from the outermost cavities was lostthe first,while the innermost gotfilled by water the last.In essence,microtexture’s spatial organization afforded shielding to the loss of the gas from the innermost cavities,which we probed as a function of the microtexture’s pitch,surface density,dimensionality,and hydrostatic pressure.These findings advance our knowledge of wetting transitions in microtextures and inspiring surface textures to protect electronic devices against liquid ingression.展开更多
The presence of bridge piers in natural rivers significantly changes the flow and boundary conditions.As a consequence,ice jams can often be initiated in front of bridge piers.With the changes in flow conditions,two t...The presence of bridge piers in natural rivers significantly changes the flow and boundary conditions.As a consequence,ice jams can often be initiated in front of bridge piers.With the changes in flow conditions,two types of ice jam formation may appear:surface accumulation of ice blocks (surface ice blockage) and thickened accumulation of ice blocks (vertical ice blockage).In the present study,the initiation process of ice jam was studied based on experiments.It is found that the critical ice concentration for ice jam blockage depends on the ice block dimension,channel opening and flow conditions.Under surface blockage conditions,a larger ratio of ice cube dimension to channel opening (between piers) can result in a smaller critical ice concentration for ice jam blockage,which has no obvious relation with flow conditions.Under vertical blockage conditions,the critical ice concentration for ice jam blockage increases with flow Froude number and decreases with the ratio of ice dimension to channel opening (between piers).Based on experiments conducted in laboratory,equations for determining critical ice concentration for these two types of ice jam blockage have been developed.展开更多
Experiments are carried out in an ＂S-shaped＂ flume in the laboratory under both open flow and ice-jammed conditions to study the impacts of bridge piers in a bend channel on the variation of the water level. The var...Experiments are carried out in an ＂S-shaped＂ flume in the laboratory under both open flow and ice-jammed conditions to study the impacts of bridge piers in a bend channel on the variation of the water level. The variations of the water level under the ice jammed condition with bridge piers are compared to those without bridge piers in an 180° bend channel. Results indicate that the bridge piers in the S-shaped channel have obvious impacts on the ice accumulation and the water level. The increment of the water level with the presence of the bridge piers is less than that without the bridge piers in the channel. Different arrangements of the bridge piers result in different increments of the water level. When one bridge pier is installed in the straight section of the channel（between 2 bends） and another one at the bend apex（for a convex bank）, the increment of the water level during the equilibrium ice jammed period is between that with a single bridge pier located in the straight section of the bend channel and that with a single bridge pier located at the bend apex. It is also shown that the increment of the water level during the equilibrium ice jammed period increases with the increase of the average thickness of the ice jams.展开更多
文摘Assessing the resilience of rice varieties against bioterrorism agents is critical to safeguarding food security.This study evaluated Food and Drug Administration-approved and recognized as safe metallic oxide nanoparticles(NPs)of zinc oxide(ZnO)and magnesium oxide(MgO)as protective strategies to reduce susceptibility in imported rice varieties to a biothreat model,Escherichia coli.Two types of rice(brown and white)from four countries(USA,Mexico,India,and Thailand)were treated with 60 mg/L NPs or their ionic forms and sterilized before inoculation.The treatments were analyzed for nutritional profiles,heavy metal content,and pathogen susceptibility.Rice organic compositions were characterized by Fourier transform infrared spectroscopy,and metal were contents quantified using inductively coupled plasma optical emission spectroscopy.Pathogenic response was monitored using ultraviolet mass spectrophotometry.The findings revealed that nutrient-rich varieties like brown rice from Mexico displayed reduced susceptibility to E.coli compared with white rice from India,which showed the highest susceptibility.NP fortification demonstrated significant antimicrobial efficacy,particularly with ZnO and MgO NPs,which were more effective than their ionic counterparts in inhibiting bacterial growth.Results showed that ZnO and MgO NP treatments reduced E.coli growth by 72%and 68%,respectively,compared with untreated controls.Brown rice from Mexican treated with MgO NPs exhibited the lowest optical density at 600 nm(OD6000.01),indicating significantly enhanced resistance to bacterial proliferation.This research underscores the potential of nano-fortification not only to improve pathogen resilience in rice but also to maintain its nutritional integrity.This study provides a foundational framework for enhancing food safety against bioterrorism agents and supports the development of resilient agricultural practices.
文摘The Regional Climate Model(RegCM)proves valuable for climate analysis and has been applied to a wide range of climate change aspects and other environmental issues at a regional scale.The model also demonstrated success in diverse areas of urban research,including urban heat island studies,extreme climate events analysis,assessing urban resilience,and evaluating urbanization impacts on climate and air quality.Recently,more studies have been conducted in utilizing RegCM to address climate change in cities,due to its enhanced ability over the years to capture meteorological phenomena at city scales.However,there are many challenges associated with its implementation in meso-scale research,which are attributed to various shortcomings and thus create room for further improvement in the model.This paper presents a comprehensive overview of the evolution of the RegCM over the years and its customisation across various parameters,demonstrating its versatility in urban climate studies and underscoring the model’s pivotal role in addressing multifaceted challenges in urban environments.By addressing these aspects,the paper offers valuable insights and recommendations for researchers seeking to enhance the accuracy and efficacy of urban climate simulations using the RegCM system,thereby contributing to the advancement of urban climate science and sustainability.
基金the research grants from the National Natural Science Foundation of China (51379208, 91425302, 51621061)the Government Public Research Funds for Projects of the Ministry of Agriculture (201503125)the Discipline Innovative Engineering Plan (111 Program, B14002)
文摘Field experiments were conducted from 2012 to 2015 in an arid region of Northwest China to investigate the effects of planting density on plant growth, yield, and water use efficiency（WUE） of maize for seed production. Five planting densities of 6.75, 8.25, 9.75, 11.25 and 12.75 plants/m^2 were conducted in 2012, and a planting density of 14.25 plants/m^2 was added from 2013 to 2015. Through comparison with the Aqua Crop yield model, a modified model was developed to estimate the biomass accumulation and yield under different planting densities using adjustment coefficient for normalized biomass water productivity and harvest index. It was found that the modified yield model had a better performance and could generate results with higher determination coefficient and lower error. The results indicated that higher planting density increased the leaf area index and biomass accumulation, but decreased the biomass accumulation per plant. The total yield increased rapidly as planting density increased to 11.25 plants/m^2, but only a slight increase was observed when the density was greater than 11.25 plants/m^2. The WUE also reached the maximum when planting density was 11.25 plants/m^2, which was the recommended planting density of maize for seed production in Northwest China.
基金supported by King Abdullah University of Science and Technology(KAUST).
文摘Currently,the most cost-effective and efficient method for phosphorus(P)removal from wastewater is enhanced biological P removal(EPBR)via polyphosphate-accumulating organisms(PAOs).This study integrates a literature review with genomic analysis to uncover the phylogenetic and metabolic diversity of the relevant PAOs for wastewater treatment.The findings highlight significant differences in the metabolic capabilities of PAOs relevant to wastewater treatment.Notably,Candidatus Dechloromonas and Candidatus Accumulibacter can synthesize polyhydroxyalkanoates,possess specific enzymes for ATP production from polyphosphate,and have electrochemical transporters for acetate and C4-dicarboxylates.In contrast,Tetrasphaera,Candidatus Phosphoribacter,Knoellia,and Phycicoccus possess PolyP-glucokinase and electrochemical transporters for sugars/amino acids.Additionally,this review explores various detection methods for polyphosphate and PAOs in activated sludge wastewater treatment plants.Notably,FISH-Raman spectroscopy emerges as one of the most advanced detection techniques.Overall,this review provides critical insights into PAO research,underscoring the need for enhanced strategies in biological phosphorus removal.
基金supported by a Competitive Research Grant(URF/1/4069-01-01)Research Translation Fund(REI/1/4576-01-01)from King Abdullah University of Science and Technology(KAUST),Saudi Arabia.
文摘Fruits,vegetables,and dairy products are typically the primary sources of household food waste.Currently,anaerobic digestion is the most used bioprocess for the treatment of food waste with concomitant generation of biogas.However,to achieve a circular carbon economy,the organics in food waste should be converted to new chemicals with higher value than energy.Here we demonstrate the feasibility of medium-chain carboxylic acid(MCCA)production from expired dairy and beverage waste via a chain elongation platform mediated by lactate.In a two-stage fermentation process,the first stage with optimized operational conditions,including varying temperatures and organic loading rates,transformed expired dairy and beverage waste into lactate at a concentration higher than 900 mM C at 43℃.This lactate was then used to produce>500 mM C caproate and>300 mM C butyrate via microbial chain elongation.Predominantly,lactate-producing microbes such as Lactobacillus and Lacticaseibacillus were regulated by temperature and could be highly enriched under mesophilic conditions in the firststage reactor.In the second-stage chain elongation reactor,the dominating microbes were primarily from the genera Megasphaera and Caproiciproducens,shaped by varying feed and inoculum sources.Cooccurrence network analysis revealed positive correlations among species from the genera Caproiciproducens,Ruminococcus,and CAG-352,as well as Megasphaera,Bacteroides,and Solobacterium,indicating strong microbial interactions that enhance caproate production.These findings suggest that producing MCCAs from expired dairy and beverage waste via lactate-mediated chain elongation is a viable method for sustainable waste management and could serve as a chemical production platform in the context of building a circular bioeconomy.
文摘In this article, the authors propose the production of ethanol from cellulose as an alternative to oil. Cellulosic-ethanol will reduce greenhouse gas emissions, and provide a means to prevent forest fires. This liquid dense fuel was selected because it： （1） easily transported and dispensed as a fuel; （2） can be handled by the existing fuel distribution infrastructure; and （3） unlike its commercial competitor, Me-OH （Methanol）, Et-OH （Ethanol）, is edible, thus being biodegradable and nontoxic. Forest residue ethanol is cheaper to produce and more environmentally friendly than other forms of ethanol fuel. Furthermore, forests would have less available ground fuel for fires. The potential decline of forest fires would then reduce the carbon footprint attributed directly to forest fires. In combination with ethanol fuel combustion, carbon emissions can be reduced by more than 70% compared to gasoline combustion. We used GREET （Greenhouse gases, Regulated Emissions, and Energy use in Transportation） software to assess the life cycles of different fuel pathways. In conclusion, cellulosic ethanol fuel is clearly an answer to decrease dependency on current oil imports and prevent forest fires.
基金Project supported by the National Science Foundation(NSF)the Environmental Protection Agency under Cooperative Agreement(No.DBI-0830117)+3 种基金the National Institutes of Health(NIH)Grant(No.2R25GM069621-09)the National Institute on Minority Health and Health Disparities(NIMHD)Grant(No.8G12MD007592)the United States Department of Agriculture(USDA)Grant(No.2011-38422-30835)the Research and Engineering Apprenticeship Program(REAP)Grant(No.W11NF-10-2-0076),USA
基金supported by the National Science Foundation (NSF)the Environmental Protection Agency(EPA) under Cooperative Agreement DBI-0830117+1 种基金the USDA grant 2011-38422-30835the NSF Grant CHE-0840525
文摘Alginates are naturally occurring components of organic matter in natural soil whose effects on nanoparticle （NP） toxicity to plants is not well understood. In the present study, corn plants were grown for one month in soil spiked with 400 mg/kg CeO2 NPs with various alginate concentrations. After one month of growth in the NPs impacted soil, plants were harvested and analyzed for Ce and mineral element concentrations. Chlorophyll concentration and heat shock protein 70, used as biomarkers for oxidative stress, were also evaluated. Results showed that, compared to CeO2 NPs treatment, alginate at 10, 50, and 100 mg/kg increased Ce concentration in roots by approximately 46%, 38%, and 29% and by 115%, 45%, and 56% in shoots, respectively. CeO 2 NPs without alginate increased Mn accumulation in roots by 34% compared to control. CeO2 NPs with low and medium alginate increased Mn by ca. 92% respect to NPs without alginate and by ca. 155% respect to control. CeO2 NPs without/with alginate significantly increased accumulation of Fe and Al in roots. In addition, alginate at 50 mg/kg increased Zn accumulation in roots by 52% compared to control. In shoots, K increased at all NP treatments but the accumulation of other elements was not affected. Alginate enlarged the impact of CeO2 NPs to corn plants by reducing chlorophyll a content and triggering overexpression of heat shock protein 70.
基金sponsored by the Irish Research Council(IRC)as a Starting Laureate Award(Grant No.IRCLA/2017/246)IRC Postdoctoral Fellowship(Grant No.GOIPD/2023/1290).
文摘Microbial aggregates of different sizes in aerobic granular sludge(AGS)systems have been shown to exhibit distinct microbial community compositions.However,studies comparing the microbial activities of different-sized aggregates in AGS systems remain limited.In this study,genome-resolved metatranscriptomics was used to investigate microbial activity patterns within differently sized aggregates in a full-scale AGS plant.Our analysis revealed a weak correlation between the relative abundance of metagenome-assembled genomes(MAGs)and their transcriptomic activity,indicating that microbial abundance does not directly correspond to metabolic activity within the system.Flocculent sludge(FL;<0.2 mm)predominantly featured active nitrifiers and fermentative polyphosphate-accumulating organisms(PAOs)from Candidatus Phosphoribacter,while small granules(SG;0.2e1.0 mm)and large granules(LG;>1.0 mm)hosted more metabolically active PAOs affiliated with Ca.Accumulibacter.Differential gene expression analysis further supported these findings,demonstrating significantly higher expression levels of key phosphorus uptake genes associated with Ca.Accumulibacter in granular sludge(SG and LG)compared to flocculent sludge.Conversely,Ca.Phosphoribacter showed higher expression of these genes in the FL fraction.This study highlights distinct functional roles and metabolic activities of crucial microbial communities depending on aggregate size within AGS systems,offering new insights into optimizing wastewater treatment processes.
文摘Numerous natural and industrial processes entail the spontaneous entrapment of gas/air as rough/patterned surfaces are submerged under water.As the wetting transitions ensue,the gas diffuses into the water leading to the fully water-filled state.However,the standard models forwetting do not accountfor the microtexture’s topography on collective wetting transitions.In other words,it is not clear whether the lifetime of n cavities arranged in a one-dimensional(I-D)line or a two-dimensional(II-D)(circular or square)lattice would be the same or not as a single 0-D cavity.In response,we tracked the time-dependentfates of gas pockets trapped in I-D and II-D lattices and compared them with wetting transitions in commensurate 0-D cavities.Interestingly,the collective wetting transitions in the I-D and the II-D arrays had a directionality such thatthe gas from the outermost cavities was lostthe first,while the innermost gotfilled by water the last.In essence,microtexture’s spatial organization afforded shielding to the loss of the gas from the innermost cavities,which we probed as a function of the microtexture’s pitch,surface density,dimensionality,and hydrostatic pressure.These findings advance our knowledge of wetting transitions in microtextures and inspiring surface textures to protect electronic devices against liquid ingression.
基金the National Natural Science Foundation of China (Grant Nos.51879065,51379054)the Project of Electric Power Construction Corporation of China (Grant No.DJ-ZDZX-2016-02).
文摘The presence of bridge piers in natural rivers significantly changes the flow and boundary conditions.As a consequence,ice jams can often be initiated in front of bridge piers.With the changes in flow conditions,two types of ice jam formation may appear:surface accumulation of ice blocks (surface ice blockage) and thickened accumulation of ice blocks (vertical ice blockage).In the present study,the initiation process of ice jam was studied based on experiments.It is found that the critical ice concentration for ice jam blockage depends on the ice block dimension,channel opening and flow conditions.Under surface blockage conditions,a larger ratio of ice cube dimension to channel opening (between piers) can result in a smaller critical ice concentration for ice jam blockage,which has no obvious relation with flow conditions.Under vertical blockage conditions,the critical ice concentration for ice jam blockage increases with flow Froude number and decreases with the ratio of ice dimension to channel opening (between piers).Based on experiments conducted in laboratory,equations for determining critical ice concentration for these two types of ice jam blockage have been developed.
基金Project supported by the National Natural Science Foundation of China(Grant No.51379054)
文摘Experiments are carried out in an ＂S-shaped＂ flume in the laboratory under both open flow and ice-jammed conditions to study the impacts of bridge piers in a bend channel on the variation of the water level. The variations of the water level under the ice jammed condition with bridge piers are compared to those without bridge piers in an 180° bend channel. Results indicate that the bridge piers in the S-shaped channel have obvious impacts on the ice accumulation and the water level. The increment of the water level with the presence of the bridge piers is less than that without the bridge piers in the channel. Different arrangements of the bridge piers result in different increments of the water level. When one bridge pier is installed in the straight section of the channel（between 2 bends） and another one at the bend apex（for a convex bank）, the increment of the water level during the equilibrium ice jammed period is between that with a single bridge pier located in the straight section of the bend channel and that with a single bridge pier located at the bend apex. It is also shown that the increment of the water level during the equilibrium ice jammed period increases with the increase of the average thickness of the ice jams.
