RSA and ellipse curve cryptography(ECC)algorithms are widely used in authentication,data security,and access control.In this paper,we analyze the basic operation of the ECC and RSA algorithms and optimize their modula...RSA and ellipse curve cryptography(ECC)algorithms are widely used in authentication,data security,and access control.In this paper,we analyze the basic operation of the ECC and RSA algorithms and optimize their modular multiplication and modular inversion algorithms.We then propose a reconfigurable modular operation architecture,with a mix-memory unit and double multiply-accumulate structures,to realize our unified,asymmetric cryptosystem structure in an operational unit.Synthesized with 55-nm CMOS process,our design runs at 588 MHz and requires only 437801µm2 of hardware resources.Our proposed design takes 21.92 and 23.36 mW for 2048-bit RSA modular multiplication and modular inversion respectively,as well as 16.16 and 15.88 mW to complete 512-bit ECC dual-field modular multiplication and modular inversion respectively.It is more energy-efficient and flexible than existing single algorithm units.Compared with existing multiple algorithm units,our proposed method shows better performance.The operation unit is embedded in a 64-bit RISC-V processor,realizing key generation,encryption and decryption,and digital signature functions of both RSA and ECC.Our proposed design takes 0.224 and 0.153 ms for 256-bit ECC point multiplication in G(p)and G(2^(m))respectively,as well as 0.96 ms to complete 1024-bit RSA exponentiation,meeting the demand for high energy efficiency.展开更多
There exists a certain amount of SO_3 in flue gas discharged from coal-fired power plants. With the operation of the selective catalystic reduction( SCR) denitrification system,SO_3 concentration in the flue gas incre...There exists a certain amount of SO_3 in flue gas discharged from coal-fired power plants. With the operation of the selective catalystic reduction( SCR) denitrification system,SO_3 concentration in the flue gas increases,which will lead to fouling,erosion and plugging of downstream equipment. In this study,the main effects of SO_3 on the safety,stability and efficiency of units were analyzed,and measures to control SO_3 were proposed.展开更多
On December 25, 2009, after the 72-hour trail operation, Unit 2 of Laxiwa Hydropower Station on the Yellow River, constructed by CPI Yellow River Hydropower Corporation, was formally
The use of green manures contributes to sustainable soil and nutrient management in agriculture;however, the responses of soil microbial communities to different fertilization regimes at the regional scale are uncerta...The use of green manures contributes to sustainable soil and nutrient management in agriculture;however, the responses of soil microbial communities to different fertilization regimes at the regional scale are uncertain. A study was undertaken across multiple sites and years in Hunan, Jiangxi, Anhui, Henan,Hubei, and Fujian provinces of South China to investigate the effects of green manuring on the structure and function of soil bacterial communities in rice-green manure cropping systems. The study included four treatments: winter fallow with no chemical fertilizer as a control(NF), milk vetch as green manure without chemical fertilizer(GM), winter fallow and chemical fertilizer(CF), and a combination of chemical fertilizer and milk vetch(GMCF).Significant differences were found in the responses of soil microbial communities at different sites, with sampling sites explaining 72.33%(F = 36.59,P = 0.001) of the community composition variation. The bacterial communities in the soils from Anhui, Henan, and Hubei were broadly similar, while those from Hunan were distinctly different from other locations. The analysis of Weighted UniFrac distances showed that milk vetch changed soil microbial communities compared with winter fallow. Proteobacteria and Chloroflexi predominated in these paddy soils;however, the application of green manures increased the relative abundance of Actinobacteria. There was evidence showing that the functional microbes which play important roles in the cycling of soil carbon, nitrogen(N), and sulfur(S) changed after several years of milk vetch utilization(linear discriminant analysis score > 2). The abundance of methane-oxidizing bacteria and S-reducing bacteria increased, and microbes involved in N fixation, nitrification, and denitrification also increased in some provinces. We concluded that the application of milk vetch changed the bacterial community structure and affected the functional groups related to nutrient transformation in soils at a regional scale.展开更多
Coal preparation is an integral part of the coal commodity supply chain. This stage of post-mining, pre-utilization beneficiation uses low-cost separation technologies to remove unwanted mineral matter and moisture wh...Coal preparation is an integral part of the coal commodity supply chain. This stage of post-mining, pre-utilization beneficiation uses low-cost separation technologies to remove unwanted mineral matter and moisture which hinder the value of the coal product. Coal preparation plants typically employ several parallel circuits of cleaning and dewatering operations, with each circuit designed to optimally treat a specific size range of coal. Recent innovations in coal preparation have increased the efficiency and capac- ity of individual unit operations while reinforcing the standard parallel cleaning approach. This article, which describes the historical influences and state-of-the-art design for the various coal preparation unit operations, is organized to distinguish between coarse/intermediate coal cleaning and fine/ultrafine coal cleaning. Size reduction, screening, classification, cleaning, dewatering, waste disposal unit operations are particularly highlighted, with a special focus on the LI.S. design philosophy. Notable differences between the U.S. and international operations are described as appropriate.展开更多
The anomaly detection of the brake operating unit (BOU) in thebrake systems on metro vehicle is critical for the safety and reliability ofthe trains. On the other hand, current periodic inspection and maintenanceare u...The anomaly detection of the brake operating unit (BOU) in thebrake systems on metro vehicle is critical for the safety and reliability ofthe trains. On the other hand, current periodic inspection and maintenanceare unable to detect anomalies in an early stage. Also, building an accurateand stable system for detecting anomalies is extremely difficult. Therefore,we present an efficient model that use an ensemble of recurrent autoencodersto accurately detect the BOU abnormalities of metro trains. This is the firstproposal to employ an ensemble deep learning technique to detect BOUabnormalities in metro train braking systems. One of the anomalous caseson metro vehicles is the case when the air cylinder (AC) pressures are less thanthe brake cylinder (BC) pressures in certain parts where the brake pressuresincrease before coming to a halt. Hence, in this work, we first extract the dataof BC and AC pressures. Then, the extracted data of BC and AC pressuresare divided into multiple subsequences that are used as an input for bothbi-directional long short-term memory (biLSTM) and bi-directional gatedrecurrent unit (biGRU) autoencoders. The biLSTM and biGRU autoencodersare trained using training dataset that only contains normal subsequences. Fordetecting abnormalities from test dataset which consists of abnormal subsequences, the mean absolute errors (MAEs) between original subsequences andreconstructed subsequences from both biLSTM and biGRU autoencoders arecalculated. As an ensemble step, the total error is calculated by averaging twoMAEs from biLSTM and biGRU autoencoders. The subsequence with totalerror greater than a pre-defined threshold value is considered an abnormality.We carried out the experiments using the BOU dataset on metro vehiclesin South Korea. Experimental results demonstrate that the ensemble modelshows better performance than other autoencoder-based models, which showsthe effectiveness of our ensemble model for detecting BOU anomalies onmetro trains.展开更多
Aspalathus linearis is a commercially important plant species endemic to the Cape Floristic Region of South Africa and is used to produce a herbal tea known as rooibos tea.Symbiotic interactions between A.linearis and...Aspalathus linearis is a commercially important plant species endemic to the Cape Floristic Region of South Africa and is used to produce a herbal tea known as rooibos tea.Symbiotic interactions between A.linearis and soil bacteria play an important role in the survival of Aspalathus plants in the highly nutrient-poor,acidic fynbos soil.The aim of this study was to characterize and compare rhizosphere and bulk soil bacterial communities associated with natural and commercially grown A.linearis,as well as the effect of seasonal changes on these communities.Bacterial communities were characterized using high throughput amplicon sequencing,and their correlations with soil chemical properties were investigated.The N-fixing bacterial community was characterized using terminal restriction fragment length polymorphism and real time quantitative polymerase chain reaction.Actinobacteria,Proteobacteria,and Acidobacteria were the most dominant bacterial phyla detected in this study.Highly similar bacterial communities were associated with natural and commercially grown plants.Significant differences in the bacterial community were observed between rhizosphere and bulk soils collected in the dry season,while no significant differences were detected in the wet season.This study provides insights into bacterial community structure and potential factors shaping bacterial community structure with commercially important A.linearis.展开更多
The stimulating effect of rhizosphere on denitrification is considered to be an unavoidable loss of soil nitrogen(N)and detrimental to crop N use efficiency,which is regulated by crop growth and soil properties.Soil a...The stimulating effect of rhizosphere on denitrification is considered to be an unavoidable loss of soil nitrogen(N)and detrimental to crop N use efficiency,which is regulated by crop growth and soil properties.Soil acidification,occurring rapidly in many intensive farming lands,affects both crop growth and soil properties,thereby altering rhizosphere effect on denitrification.However,the mechanism by which soil acidification regulates rhizosphere denitrification still remains unclear.Here,we determined the denitrification capacity(DC)and associated community compositions of nirK-and nirS-type denitrifiers in maize rhizosphere and bulk soils at four acidity gradients(pH=6.8,6.1,5.2,and 4.2).Results showed that the stimulating effect of rhizosphere on DC strongly depended on soil pH.Compared to bulk soil,rhizosphere soil had significantly higher DC at pH 5.2,but not at pH of 4.2.With increasing soil acidity,the stimulation of rhizosphere on DC(calculated as the difference in DC between rhizosphere and bulk soils)decreased from 8.01 to 0.01 mg N kg-1d-1.Moreover,soil acidification significantly reduced the differences in dissolved organic carbon(DOC)and abundance of key nirK-type denitrifier taxa between rhizosphere and bulk soils,both of which were positively related to the stimulation of rhizosphere on DC.These findings demonstrated that soil acidification could weaken the positive rhizosphere effect on denitrification via regulated C availability and associated nirK-type denitrifier community,potentially reducing N loss risk in rhizosphere soil.The independent role of soil p H should be fully considered when modelling N behaviour in plant-soil systems.展开更多
Ammonia-oxidizing archaea(AOA)are important in converting ammonia into nitrate in soils.While many aspects of their community structure have been studied,the relative importance of stochastic versus deterministic proc...Ammonia-oxidizing archaea(AOA)are important in converting ammonia into nitrate in soils.While many aspects of their community structure have been studied,the relative importance of stochastic versus deterministic processes has poorly been understood.We compared AOA communities across the North China Plain,targeting the amoA gene.A phylogenetic null modelling approach was used to calculate the beta nearest taxon index to quantify the influence of stochastic and deterministic processes.We found that spatial distance between samples predicted the perceived processes involved in community structuring,with stochastic processes dominating at local scales.At greater distances,stochasticity became weaker.However,soil pH,which was also the strongest determinant of AOA community,was a much stronger predictor of community structuring,leaving the distance effect redundant as an explanation of community structuring processes.The communities of AOA differing by less than 1 pH unit differed mainly stochastically in terms of operational taxonomic unit composition.At larger pH differences,deterministic processes based on heterogeneous selection between clades became increasingly dominant.It appears that AOA community composition is largely determined by the environment.However,very similar pH environments are the exception.In environments with very close pH values,stochastic effects dominantly cause differences in community composition,whether spatially near or far.展开更多
A detailed experiment of 1-pixel bit reconfigurable ternary optical processor （TOP） is proposed in the paper. 42 basic operation units （BOUs） and 28 typical logic operators of the TOP are realized in the experimen...A detailed experiment of 1-pixel bit reconfigurable ternary optical processor （TOP） is proposed in the paper. 42 basic operation units （BOUs） and 28 typical logic operators of the TOP are realized in the experiment. Results of the test cases elaborately cover the every combination of BOUs and all the nine inputs of ternary processor. Both the experiment process and results analysis are given in this paper. The experimental results demonstrate that the theory of reconfiguring a TOP is valid and that the reconfiguration circuitry is effective.展开更多
Malaria remains a global health problem.The relationship between Plasmodium spp.and the gut microbiota as well as the impact of Plasmodium spp.on the gut microbiota in vertebrate hosts is unclear.The aim of the curren...Malaria remains a global health problem.The relationship between Plasmodium spp.and the gut microbiota as well as the impact of Plasmodium spp.on the gut microbiota in vertebrate hosts is unclear.The aim of the current study was to evaluate the effect of blood-stage Plasmodium parasites on the gut microbiota of mice.The gut microbiota was analyzed by 16S rRNA sequencing and bioinformatic analyses at three stages.The gut microbiota changed during the three phases:the healthy stage,the infection stage,and the cure stage(on the 9th day after malarial elimination).Moreover,the gut microbiota of these infected animals did not recover after malaria infection.There were 254 operational taxonomic units(OTUs)across all three stages,and there were unique strains or OTUs at each stage of the experiment.The percentages of community abundance of 8 OTUs changed significantly(P<0.05).The dominant OTU in both the healthy mice and the mice with malaria was OTU265,while that in the cured mice was OTU234.In addition,the changes in OTU147 were the most noteworthy.Its percentage of community abundance varied greatly,with higher values during malaria than before malaria infection and after malaria elimination.These results indicated that the external environment influenced the gut microbiota after host C57BL/6 mice were infected with blood-stage P.berghei ANKA and that the same was true during and after elimination of blood-stage P.berghei ANKA.In addition,we could not isolate OTU147 for further study.This study identified gut microbiota components that were reconstructed after infection by and elimination of blood-stage P.berghei ANKA in host C57BL/6 mice,and this process was affected by P.berghei ANKA and the external environment of the host.展开更多
Eighteen agar media were tested for the culture of gut-associated bacteria from farmed adult turbot （Scophthalmus maximus）, including 16 agar media with or without 1% gastrointestinal （GI） supernatant, or with 2% ...Eighteen agar media were tested for the culture of gut-associated bacteria from farmed adult turbot （Scophthalmus maximus）, including 16 agar media with or without 1% gastrointestinal （GI） supernatant, or with 2% or 4% GI supernatant. A total of 1 711 colonies were analyzed and 24 operational taxonomic units （OTUs） were identified. The greatest bacterial diversity was isolated on Zobell 2216E/ Zobell 2216E＋ agar media, whereas MRS/MRS＋ agar media produced a low diversity of colonies, Agar media with GI supernatant （1%, 2%, or 4%） showed increased diversity and yielded different profiles of OTUs from the corresponding original media, suggesting that GI supernatant provides substances that enhance the culture efficiency of bacteria from the turbot GI tract. The large majority of the colonies （82%） were 7-Proteobacteria, whereas 15.6% and 2.4% of colonies were Firmicutes and Actinobacteria, respectively. At the genus level, 49.4% of all colonies were assigned to Vibrio. Other potential pathogens, including Pseudomonas, Photobacterium, and Enterobacter, and potential probiotics, including Bacillus, Paenibacillus, and Pseudomonas, were also isolated on agar media. Most cultured bacteria belonged to species that were first described in the turbot GI tract. The impact of these species on turbot physiology and health should be investigated further.展开更多
Objective:To explore the structural and functional characteristics of microbiota in oropharynx of subhealthy children with gastrointestinal heat retention syndrome(GHRS)differentiated by traditional Chinese medicine,a...Objective:To explore the structural and functional characteristics of microbiota in oropharynx of subhealthy children with gastrointestinal heat retention syndrome(GHRS)differentiated by traditional Chinese medicine,and screen the biometric operational taxonomic units(OTUs)to assist the clinical diagnosis.Methods:We recruited children according to the“GHRS diagnostic scale”,collected their oropharyngeal swabs,and sequenced the 16 SrDNA V4 region.We described the bacterial structure with alpha-indexes,beta-distances,and relative abundances;moreover,we screened the differential genera/OTUs with Wilcoxon rank-sum test,Metagenome Seq analysis,and linear discriminant analysis effect size(LEf Se)analysis,in which biometric OTUs were selected to construct the receiver operating characteristic curve to verify the diagnostic value.The bacterial function was predicted with Kyoto Encyclopedia of Genes and Genomes pathways according to 16S rDNA gene by using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States.Results:The study population was composed of 10 children with GHRS and 10 healthy control children.GHRS children were more likely to overeat(gluttony,P=.033).Alpha-indexes,such as Sobs,abundancebased coverage estimator,Bootstrap,and Qstat,were significantly higher in the GHRS group,while betadistances did not exhibit any significant intergroup differences.There were 9 differently distributed nonpredominant genera between the groups in Wilcoxon rank-sum test,as well as 13 non-predominant genera in Metagenome Seq analysis and 3 non-predominant OTUs in LEfSe analysis.OTU44 and OTU196 were used to construct the receiver operating characteristic curve,and the area under curve was 0.92.Predicted functions showed that pathways related to oxidative phosphorylation and carbon metabolism were enriched in healthy control samples,while the pathway related to renin secretion was remarkably enriched in GHRS samples.Conclusion:Unique oropharyngeal microbial structure and function were identified in GHRS children.OTU44 and OTU196 were specific OTUs,which could be used as biomarkers of GHRS to assist clinical diagnosis.展开更多
文摘RSA and ellipse curve cryptography(ECC)algorithms are widely used in authentication,data security,and access control.In this paper,we analyze the basic operation of the ECC and RSA algorithms and optimize their modular multiplication and modular inversion algorithms.We then propose a reconfigurable modular operation architecture,with a mix-memory unit and double multiply-accumulate structures,to realize our unified,asymmetric cryptosystem structure in an operational unit.Synthesized with 55-nm CMOS process,our design runs at 588 MHz and requires only 437801µm2 of hardware resources.Our proposed design takes 21.92 and 23.36 mW for 2048-bit RSA modular multiplication and modular inversion respectively,as well as 16.16 and 15.88 mW to complete 512-bit ECC dual-field modular multiplication and modular inversion respectively.It is more energy-efficient and flexible than existing single algorithm units.Compared with existing multiple algorithm units,our proposed method shows better performance.The operation unit is embedded in a 64-bit RISC-V processor,realizing key generation,encryption and decryption,and digital signature functions of both RSA and ECC.Our proposed design takes 0.224 and 0.153 ms for 256-bit ECC point multiplication in G(p)and G(2^(m))respectively,as well as 0.96 ms to complete 1024-bit RSA exponentiation,meeting the demand for high energy efficiency.
基金Supported by National High Technology Research and Development Program of China(863 Program)(2013AA065401)
文摘There exists a certain amount of SO_3 in flue gas discharged from coal-fired power plants. With the operation of the selective catalystic reduction( SCR) denitrification system,SO_3 concentration in the flue gas increases,which will lead to fouling,erosion and plugging of downstream equipment. In this study,the main effects of SO_3 on the safety,stability and efficiency of units were analyzed,and measures to control SO_3 were proposed.
文摘On December 25, 2009, after the 72-hour trail operation, Unit 2 of Laxiwa Hydropower Station on the Yellow River, constructed by CPI Yellow River Hydropower Corporation, was formally
基金supported by the earmarked fund for Modern Agro-industry Technology Research System-Green Manure,China (No.CARS-22)the National Natural Science Foundation of China (No.42007071)。
文摘The use of green manures contributes to sustainable soil and nutrient management in agriculture;however, the responses of soil microbial communities to different fertilization regimes at the regional scale are uncertain. A study was undertaken across multiple sites and years in Hunan, Jiangxi, Anhui, Henan,Hubei, and Fujian provinces of South China to investigate the effects of green manuring on the structure and function of soil bacterial communities in rice-green manure cropping systems. The study included four treatments: winter fallow with no chemical fertilizer as a control(NF), milk vetch as green manure without chemical fertilizer(GM), winter fallow and chemical fertilizer(CF), and a combination of chemical fertilizer and milk vetch(GMCF).Significant differences were found in the responses of soil microbial communities at different sites, with sampling sites explaining 72.33%(F = 36.59,P = 0.001) of the community composition variation. The bacterial communities in the soils from Anhui, Henan, and Hubei were broadly similar, while those from Hunan were distinctly different from other locations. The analysis of Weighted UniFrac distances showed that milk vetch changed soil microbial communities compared with winter fallow. Proteobacteria and Chloroflexi predominated in these paddy soils;however, the application of green manures increased the relative abundance of Actinobacteria. There was evidence showing that the functional microbes which play important roles in the cycling of soil carbon, nitrogen(N), and sulfur(S) changed after several years of milk vetch utilization(linear discriminant analysis score > 2). The abundance of methane-oxidizing bacteria and S-reducing bacteria increased, and microbes involved in N fixation, nitrification, and denitrification also increased in some provinces. We concluded that the application of milk vetch changed the bacterial community structure and affected the functional groups related to nutrient transformation in soils at a regional scale.
文摘Coal preparation is an integral part of the coal commodity supply chain. This stage of post-mining, pre-utilization beneficiation uses low-cost separation technologies to remove unwanted mineral matter and moisture which hinder the value of the coal product. Coal preparation plants typically employ several parallel circuits of cleaning and dewatering operations, with each circuit designed to optimally treat a specific size range of coal. Recent innovations in coal preparation have increased the efficiency and capac- ity of individual unit operations while reinforcing the standard parallel cleaning approach. This article, which describes the historical influences and state-of-the-art design for the various coal preparation unit operations, is organized to distinguish between coarse/intermediate coal cleaning and fine/ultrafine coal cleaning. Size reduction, screening, classification, cleaning, dewatering, waste disposal unit operations are particularly highlighted, with a special focus on the LI.S. design philosophy. Notable differences between the U.S. and international operations are described as appropriate.
基金This research is supported by the Korea Agency for Infrastructure Technology Advancement(KAIA)grant funded by the Ministry of Land,Infrastructure and Transport(Grant21QPWO-B152223-03).
文摘The anomaly detection of the brake operating unit (BOU) in thebrake systems on metro vehicle is critical for the safety and reliability ofthe trains. On the other hand, current periodic inspection and maintenanceare unable to detect anomalies in an early stage. Also, building an accurateand stable system for detecting anomalies is extremely difficult. Therefore,we present an efficient model that use an ensemble of recurrent autoencodersto accurately detect the BOU abnormalities of metro trains. This is the firstproposal to employ an ensemble deep learning technique to detect BOUabnormalities in metro train braking systems. One of the anomalous caseson metro vehicles is the case when the air cylinder (AC) pressures are less thanthe brake cylinder (BC) pressures in certain parts where the brake pressuresincrease before coming to a halt. Hence, in this work, we first extract the dataof BC and AC pressures. Then, the extracted data of BC and AC pressuresare divided into multiple subsequences that are used as an input for bothbi-directional long short-term memory (biLSTM) and bi-directional gatedrecurrent unit (biGRU) autoencoders. The biLSTM and biGRU autoencodersare trained using training dataset that only contains normal subsequences. Fordetecting abnormalities from test dataset which consists of abnormal subsequences, the mean absolute errors (MAEs) between original subsequences andreconstructed subsequences from both biLSTM and biGRU autoencoders arecalculated. As an ensemble step, the total error is calculated by averaging twoMAEs from biLSTM and biGRU autoencoders. The subsequence with totalerror greater than a pre-defined threshold value is considered an abnormality.We carried out the experiments using the BOU dataset on metro vehiclesin South Korea. Experimental results demonstrate that the ensemble modelshows better performance than other autoencoder-based models, which showsthe effectiveness of our ensemble model for detecting BOU anomalies onmetro trains.
基金supported by the National Research Foundation Biodiversity Information Program:Biodiversity Surveys in Priority Inland Areas(FBIP)(South Africa)(No.87602)the National Research Foundation for funding the equipment based at the Central Analytical Facilities of Stellenbosch University,South Africa(No.74452)
文摘Aspalathus linearis is a commercially important plant species endemic to the Cape Floristic Region of South Africa and is used to produce a herbal tea known as rooibos tea.Symbiotic interactions between A.linearis and soil bacteria play an important role in the survival of Aspalathus plants in the highly nutrient-poor,acidic fynbos soil.The aim of this study was to characterize and compare rhizosphere and bulk soil bacterial communities associated with natural and commercially grown A.linearis,as well as the effect of seasonal changes on these communities.Bacterial communities were characterized using high throughput amplicon sequencing,and their correlations with soil chemical properties were investigated.The N-fixing bacterial community was characterized using terminal restriction fragment length polymorphism and real time quantitative polymerase chain reaction.Actinobacteria,Proteobacteria,and Acidobacteria were the most dominant bacterial phyla detected in this study.Highly similar bacterial communities were associated with natural and commercially grown plants.Significant differences in the bacterial community were observed between rhizosphere and bulk soils collected in the dry season,while no significant differences were detected in the wet season.This study provides insights into bacterial community structure and potential factors shaping bacterial community structure with commercially important A.linearis.
基金supported by the Scientific Research Projects in Higher Education Institutions in Anhui Province,China(No.2022AH050876)Anhui Provincial Natural Science Foundation,China(No.2108085QC112)。
文摘The stimulating effect of rhizosphere on denitrification is considered to be an unavoidable loss of soil nitrogen(N)and detrimental to crop N use efficiency,which is regulated by crop growth and soil properties.Soil acidification,occurring rapidly in many intensive farming lands,affects both crop growth and soil properties,thereby altering rhizosphere effect on denitrification.However,the mechanism by which soil acidification regulates rhizosphere denitrification still remains unclear.Here,we determined the denitrification capacity(DC)and associated community compositions of nirK-and nirS-type denitrifiers in maize rhizosphere and bulk soils at four acidity gradients(pH=6.8,6.1,5.2,and 4.2).Results showed that the stimulating effect of rhizosphere on DC strongly depended on soil pH.Compared to bulk soil,rhizosphere soil had significantly higher DC at pH 5.2,but not at pH of 4.2.With increasing soil acidity,the stimulation of rhizosphere on DC(calculated as the difference in DC between rhizosphere and bulk soils)decreased from 8.01 to 0.01 mg N kg-1d-1.Moreover,soil acidification significantly reduced the differences in dissolved organic carbon(DOC)and abundance of key nirK-type denitrifier taxa between rhizosphere and bulk soils,both of which were positively related to the stimulation of rhizosphere on DC.These findings demonstrated that soil acidification could weaken the positive rhizosphere effect on denitrification via regulated C availability and associated nirK-type denitrifier community,potentially reducing N loss risk in rhizosphere soil.The independent role of soil p H should be fully considered when modelling N behaviour in plant-soil systems.
文摘Ammonia-oxidizing archaea(AOA)are important in converting ammonia into nitrate in soils.While many aspects of their community structure have been studied,the relative importance of stochastic versus deterministic processes has poorly been understood.We compared AOA communities across the North China Plain,targeting the amoA gene.A phylogenetic null modelling approach was used to calculate the beta nearest taxon index to quantify the influence of stochastic and deterministic processes.We found that spatial distance between samples predicted the perceived processes involved in community structuring,with stochastic processes dominating at local scales.At greater distances,stochasticity became weaker.However,soil pH,which was also the strongest determinant of AOA community,was a much stronger predictor of community structuring,leaving the distance effect redundant as an explanation of community structuring processes.The communities of AOA differing by less than 1 pH unit differed mainly stochastically in terms of operational taxonomic unit composition.At larger pH differences,deterministic processes based on heterogeneous selection between clades became increasingly dominant.It appears that AOA community composition is largely determined by the environment.However,very similar pH environments are the exception.In environments with very close pH values,stochastic effects dominantly cause differences in community composition,whether spatially near or far.
基金Project supported by the National Natural Science Foundation of China(Grant No.61073049)the Shanghai Leading Academic Discipline Project(Grant No.J50103)the Doctorate Foundation of Education Ministry of China(Grant No.20093108110016)
文摘A detailed experiment of 1-pixel bit reconfigurable ternary optical processor （TOP） is proposed in the paper. 42 basic operation units （BOUs） and 28 typical logic operators of the TOP are realized in the experiment. Results of the test cases elaborately cover the every combination of BOUs and all the nine inputs of ternary processor. Both the experiment process and results analysis are given in this paper. The experimental results demonstrate that the theory of reconfiguring a TOP is valid and that the reconfiguration circuitry is effective.
基金the Nature Science Foundation of Hainan Province(No.817145)College Student Innovation and Entrepreneurship Project(No.201611810082,No.HYCX2015063).
文摘Malaria remains a global health problem.The relationship between Plasmodium spp.and the gut microbiota as well as the impact of Plasmodium spp.on the gut microbiota in vertebrate hosts is unclear.The aim of the current study was to evaluate the effect of blood-stage Plasmodium parasites on the gut microbiota of mice.The gut microbiota was analyzed by 16S rRNA sequencing and bioinformatic analyses at three stages.The gut microbiota changed during the three phases:the healthy stage,the infection stage,and the cure stage(on the 9th day after malarial elimination).Moreover,the gut microbiota of these infected animals did not recover after malaria infection.There were 254 operational taxonomic units(OTUs)across all three stages,and there were unique strains or OTUs at each stage of the experiment.The percentages of community abundance of 8 OTUs changed significantly(P<0.05).The dominant OTU in both the healthy mice and the mice with malaria was OTU265,while that in the cured mice was OTU234.In addition,the changes in OTU147 were the most noteworthy.Its percentage of community abundance varied greatly,with higher values during malaria than before malaria infection and after malaria elimination.These results indicated that the external environment influenced the gut microbiota after host C57BL/6 mice were infected with blood-stage P.berghei ANKA and that the same was true during and after elimination of blood-stage P.berghei ANKA.In addition,we could not isolate OTU147 for further study.This study identified gut microbiota components that were reconstructed after infection by and elimination of blood-stage P.berghei ANKA in host C57BL/6 mice,and this process was affected by P.berghei ANKA and the external environment of the host.
基金Supported by the National High Technology Research and Development Program of China(863 Program)(No.2007AA09Z444)
文摘Eighteen agar media were tested for the culture of gut-associated bacteria from farmed adult turbot （Scophthalmus maximus）, including 16 agar media with or without 1% gastrointestinal （GI） supernatant, or with 2% or 4% GI supernatant. A total of 1 711 colonies were analyzed and 24 operational taxonomic units （OTUs） were identified. The greatest bacterial diversity was isolated on Zobell 2216E/ Zobell 2216E＋ agar media, whereas MRS/MRS＋ agar media produced a low diversity of colonies, Agar media with GI supernatant （1%, 2%, or 4%） showed increased diversity and yielded different profiles of OTUs from the corresponding original media, suggesting that GI supernatant provides substances that enhance the culture efficiency of bacteria from the turbot GI tract. The large majority of the colonies （82%） were 7-Proteobacteria, whereas 15.6% and 2.4% of colonies were Firmicutes and Actinobacteria, respectively. At the genus level, 49.4% of all colonies were assigned to Vibrio. Other potential pathogens, including Pseudomonas, Photobacterium, and Enterobacter, and potential probiotics, including Bacillus, Paenibacillus, and Pseudomonas, were also isolated on agar media. Most cultured bacteria belonged to species that were first described in the turbot GI tract. The impact of these species on turbot physiology and health should be investigated further.
基金supported by the National Natural Science Foundation of China(81373769)the Scientific Research and Postgraduate Training Co-construction Project of Beijing Municipal Education Commission(1000062520115)the Province Natural Science Foundation of Beijing(7172131)。
文摘Objective:To explore the structural and functional characteristics of microbiota in oropharynx of subhealthy children with gastrointestinal heat retention syndrome(GHRS)differentiated by traditional Chinese medicine,and screen the biometric operational taxonomic units(OTUs)to assist the clinical diagnosis.Methods:We recruited children according to the“GHRS diagnostic scale”,collected their oropharyngeal swabs,and sequenced the 16 SrDNA V4 region.We described the bacterial structure with alpha-indexes,beta-distances,and relative abundances;moreover,we screened the differential genera/OTUs with Wilcoxon rank-sum test,Metagenome Seq analysis,and linear discriminant analysis effect size(LEf Se)analysis,in which biometric OTUs were selected to construct the receiver operating characteristic curve to verify the diagnostic value.The bacterial function was predicted with Kyoto Encyclopedia of Genes and Genomes pathways according to 16S rDNA gene by using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States.Results:The study population was composed of 10 children with GHRS and 10 healthy control children.GHRS children were more likely to overeat(gluttony,P=.033).Alpha-indexes,such as Sobs,abundancebased coverage estimator,Bootstrap,and Qstat,were significantly higher in the GHRS group,while betadistances did not exhibit any significant intergroup differences.There were 9 differently distributed nonpredominant genera between the groups in Wilcoxon rank-sum test,as well as 13 non-predominant genera in Metagenome Seq analysis and 3 non-predominant OTUs in LEfSe analysis.OTU44 and OTU196 were used to construct the receiver operating characteristic curve,and the area under curve was 0.92.Predicted functions showed that pathways related to oxidative phosphorylation and carbon metabolism were enriched in healthy control samples,while the pathway related to renin secretion was remarkably enriched in GHRS samples.Conclusion:Unique oropharyngeal microbial structure and function were identified in GHRS children.OTU44 and OTU196 were specific OTUs,which could be used as biomarkers of GHRS to assist clinical diagnosis.
