Microbial extracellular electron transfer(EET) is electron exchanges between the quinol/quinone pools in microbial cytoplasmic membrane and extracellular substrates. Microorganisms with EET capabilities are widespread...Microbial extracellular electron transfer(EET) is electron exchanges between the quinol/quinone pools in microbial cytoplasmic membrane and extracellular substrates. Microorganisms with EET capabilities are widespread in Earth hydrosphere, such as sediments of rivers, lakes and oceans, where they play crucial roles in biogeochemical cycling of key elements, including carbon,nitrogen, sulfur, iron and manganese. Over the past 12 years, significant progress has been made in mechanistic understanding of microbial EET at the molecular level. In this review, we focus on the molecular mechanisms underlying the microbial ability for extracellular redox transformation of iron, direct interspecies electron transfer as well as long distance electron transfer mediated by the cable bacteria in the hydrosphere.展开更多
保护自然植被和营造人工植被是黄土高原植被恢复的重要措施,为定量阐明该区域典型植被类型的生态服务功能,合理评估不同恢复植被措施的生态效益,选取了两种典型森林生态系统(刺槐人工林和辽东栎天然次生林),基于多年连续调查数据分析了...保护自然植被和营造人工植被是黄土高原植被恢复的重要措施,为定量阐明该区域典型植被类型的生态服务功能,合理评估不同恢复植被措施的生态效益,选取了两种典型森林生态系统(刺槐人工林和辽东栎天然次生林),基于多年连续调查数据分析了其碳汇功能特征。采用以胸径和树高为基础变量的生物量方程估算了乔木层生物量;采用样方收获法测算了灌木、草本和凋落物现存量;依据两次样地调查的数据(间隔9年)和连续多年凋落物收集的数据,估算了两种森林生态系统的净初级生产力和固碳速率;再结合对两种林地土壤CO2排放的监测与分析结果进一步估算了两种生态系统的碳汇功能。结果表明:刺槐林的生物量碳密度(67.63 t C/hm2)略低于辽东栎林(76.85 t C/hm2),林分内各组分碳密度仅在乔木叶部分差异显著。研究期间刺槐林和辽东栎林的生物量年均增长量分别为15.20,18.21 t/(hm2·a);植被层年均固碳量分别为7.57,8.91 t C/(hm2·a)。因刺槐林地的土壤异养呼吸速率低于辽东栎林地,故其碳汇功能相对较高。展开更多
Data hierarchy,as a hidden property of data structure,exists in a wide range of machine learning applications.A common practice to classify such hierarchical data is first to encode the data in the Euclidean space,and...Data hierarchy,as a hidden property of data structure,exists in a wide range of machine learning applications.A common practice to classify such hierarchical data is first to encode the data in the Euclidean space,and then train a Euclidean classifier.However,such a paradigm leads to a performance drop due to distortion of data embedding in the Euclidean space.To relieve this issue,hyperbolic geometry is investigated as an alternative space to encode the hierarchical data for its higher ability to capture the hierarchical structures.Those methods cannot explore the full potential of the hyperbolic geometry,in the sense that such methods define the hyperbolic operations in the tangent plane,causing the distortion of data embeddings.In this paper,we develop two novel kernel formulations in the hyperbolic space,with one being positive definite(PD)and another one being indefinite,to solve the classification tasks in hyperbolic space.The PD one is defined via mapping the hyperbolic data to the Drury-Arveson(DA)space,which is a special reproducing kernel Hilbert space(RKHS).To further increase the discrimination of the classifier,an indefinite kernel is further defined in the Krein spaces.Specifically,we design a 2-layer nested indefinite kernel which first maps hyperbolic data into the DA spaces,followed by a mapping from the DA spaces to the Krein spaces.Extensive experiments on real-world datasets demonstrate the superiority ofthe proposed kernels.展开更多
Electromicrobiology is a sub-discipline of microbiology that investigates electrical interplay between microorganisms and redox active materials, such as electrodes and solid-phase minerals, and the mechanisms underly...Electromicrobiology is a sub-discipline of microbiology that investigates electrical interplay between microorganisms and redox active materials, such as electrodes and solid-phase minerals, and the mechanisms underlying microbial ability to exchange electrons with the redox active materials that are external to the microbial cells. The microorganisms with extracellular electron transfer capability are often referred to as exoelectrogens. Although exoelectrogens were documented in early 1900’s, discovery of the dissimilatory metal-reducing microorganisms Geobacter and Shewanella spp. in late 1980’s marked the beginning of modern electromicrobiology. Since then, thorough and rigorous studies have made Geobacter and Shewanella spp. the two best characterized groups of exoelectrogens. These include identification and characterization of the molecular mechanisms for exchanging electrons with electrodes by Geobacter sulfurreducens and Shewanella oneidensis. In addition, a variety of applications of Geobacter and Shewanella spp. in microbial fuel cells and electrobiosynthesis, such as maintenance of redox balance during fermentations and bioremediations, have also been developed. This review briefly discusses the molecular mechanisms by which G. sulfurreducens and S. oneidensis exchange electrons with electrodes and then focuses on biotechnological applications of Geobacter and Shewanella spp. in microbial fuel cells and electrobiosynthesis as well as the future directions of this research area.展开更多
In this study, a series of random conjugated polymers (PBDB-TBTn) as donors were designed and synthesized. In these polymers, benzodithiophene unit with thiophene conjugated side chains (BDT) are donor part, and two d...In this study, a series of random conjugated polymers (PBDB-TBTn) as donors were designed and synthesized. In these polymers, benzodithiophene unit with thiophene conjugated side chains (BDT) are donor part, and two different content of benzo[1,2-c:4,5-c']dithiophene-4,8-dione (BDD) and difluorobenzothiadizole (BT) linked alkylthiophene are acceptor unit. Polymer solar cells (PSCs) were fabricated with ITIC as an acceptor, and over the power conversion efficiency (PCE) of 9%was obtained, with open circuit voltage (Voc) of 0.86 V, short-circuit current density (Jsc) of 16.84 mA/cm^2, and fill factor (FF) of 62.5%. These random conjugated polymers based solar cells are insensitive to solvent additives and thermal annealing. The performance of the device decreases gradually with the increasing of the proportion of fluorinated acceptor unit. The declining efficiency is due to the excessive fluorinated acceptor unit, which leads to over aggregated topography, destroys the effective charge transport pathways, and affects phase separation domain size between the donor and the acceptor. The phenomena are explained by the charge carrier recombination, atomic force microscope (AFM), and transmission electron microscope (TEM). These results indicate that proper addition of fluorinated acceptor units to build random copolymers can enhance the efficiency of organic photovoltaics toward additive-free and thermal annealing-free PSCs.展开更多
Recognized as a pivotal developmental transition,flowering marks the continuation of a plant’s life cycle.Vernalization and pho-toperiod are two major flowering pathways orchestrating numerous florigenic signals.Meth...Recognized as a pivotal developmental transition,flowering marks the continuation of a plant’s life cycle.Vernalization and pho-toperiod are two major flowering pathways orchestrating numerous florigenic signals.Methylation,including histone,DNA and RNA methylation,is one of the recent foci in plant development.Considerable studies reveal that methylation seems to show an increasing potential regulatory role in plant flowering via altering relevant gene expression without altering the genetic basis.However,little has been reviewed about whether and how methylation acts on vernalization-and photoperiod-induced flowering before and after FLOWERING LOCUS C(FLC)reactivation,what role RNA methylation plays in vernalization-and photoperiod-induced flowering,how methylation participates simultaneously in both vernalization-and photoperiod-induced flowering,the heritability of methylation memory under the vernalization/photoperiod pathway,and whether and how methylation replaces vernalization/photoinduction to regulate flowering.Our review provides insight about the crosstalk among the genetic control of the flowering gene network,methylation(methyltransferases/demethylases)and external signals(cold,light,sRNA and phytohormones)in vernalization and photoperiod pathways.The existing evidence that RNA methylation may play a potential regulatory role in vernalization-and photoperiod-induced flowering has been gathered and represented for the first time.This review speculates about and discusses the possibility of substituting methylation for vernalization and photoinduction to promote flowering.Current evidence is utilized to discuss the possibility of future methylation reagents becoming flowering regulators at the molecular level.展开更多
基金supported by the National Natural Science Foundation of China (NSFC91851211 41772363)+1 种基金One Hundred Talents Program of Hubei ProvinceChina University of Geosciences-Wuhan
文摘Microbial extracellular electron transfer(EET) is electron exchanges between the quinol/quinone pools in microbial cytoplasmic membrane and extracellular substrates. Microorganisms with EET capabilities are widespread in Earth hydrosphere, such as sediments of rivers, lakes and oceans, where they play crucial roles in biogeochemical cycling of key elements, including carbon,nitrogen, sulfur, iron and manganese. Over the past 12 years, significant progress has been made in mechanistic understanding of microbial EET at the molecular level. In this review, we focus on the molecular mechanisms underlying the microbial ability for extracellular redox transformation of iron, direct interspecies electron transfer as well as long distance electron transfer mediated by the cable bacteria in the hydrosphere.
文摘保护自然植被和营造人工植被是黄土高原植被恢复的重要措施,为定量阐明该区域典型植被类型的生态服务功能,合理评估不同恢复植被措施的生态效益,选取了两种典型森林生态系统(刺槐人工林和辽东栎天然次生林),基于多年连续调查数据分析了其碳汇功能特征。采用以胸径和树高为基础变量的生物量方程估算了乔木层生物量;采用样方收获法测算了灌木、草本和凋落物现存量;依据两次样地调查的数据(间隔9年)和连续多年凋落物收集的数据,估算了两种森林生态系统的净初级生产力和固碳速率;再结合对两种林地土壤CO2排放的监测与分析结果进一步估算了两种生态系统的碳汇功能。结果表明:刺槐林的生物量碳密度(67.63 t C/hm2)略低于辽东栎林(76.85 t C/hm2),林分内各组分碳密度仅在乔木叶部分差异显著。研究期间刺槐林和辽东栎林的生物量年均增长量分别为15.20,18.21 t/(hm2·a);植被层年均固碳量分别为7.57,8.91 t C/(hm2·a)。因刺槐林地的土壤异养呼吸速率低于辽东栎林地,故其碳汇功能相对较高。
基金supported by the National Natural Science Foundation of China(Grant No.62076062)the Fundamental Research Funds for the Central Universities(2242021k30056).
文摘Data hierarchy,as a hidden property of data structure,exists in a wide range of machine learning applications.A common practice to classify such hierarchical data is first to encode the data in the Euclidean space,and then train a Euclidean classifier.However,such a paradigm leads to a performance drop due to distortion of data embedding in the Euclidean space.To relieve this issue,hyperbolic geometry is investigated as an alternative space to encode the hierarchical data for its higher ability to capture the hierarchical structures.Those methods cannot explore the full potential of the hyperbolic geometry,in the sense that such methods define the hyperbolic operations in the tangent plane,causing the distortion of data embeddings.In this paper,we develop two novel kernel formulations in the hyperbolic space,with one being positive definite(PD)and another one being indefinite,to solve the classification tasks in hyperbolic space.The PD one is defined via mapping the hyperbolic data to the Drury-Arveson(DA)space,which is a special reproducing kernel Hilbert space(RKHS).To further increase the discrimination of the classifier,an indefinite kernel is further defined in the Krein spaces.Specifically,we design a 2-layer nested indefinite kernel which first maps hyperbolic data into the DA spaces,followed by a mapping from the DA spaces to the Krein spaces.Extensive experiments on real-world datasets demonstrate the superiority ofthe proposed kernels.
基金supported by the National Natural Science Foundation of China(Grant Nos.NSFC91851211&41772363)the One Hundred Talents Program of Hubei Province and China University of Geosciences-Wuhan
文摘Electromicrobiology is a sub-discipline of microbiology that investigates electrical interplay between microorganisms and redox active materials, such as electrodes and solid-phase minerals, and the mechanisms underlying microbial ability to exchange electrons with the redox active materials that are external to the microbial cells. The microorganisms with extracellular electron transfer capability are often referred to as exoelectrogens. Although exoelectrogens were documented in early 1900’s, discovery of the dissimilatory metal-reducing microorganisms Geobacter and Shewanella spp. in late 1980’s marked the beginning of modern electromicrobiology. Since then, thorough and rigorous studies have made Geobacter and Shewanella spp. the two best characterized groups of exoelectrogens. These include identification and characterization of the molecular mechanisms for exchanging electrons with electrodes by Geobacter sulfurreducens and Shewanella oneidensis. In addition, a variety of applications of Geobacter and Shewanella spp. in microbial fuel cells and electrobiosynthesis, such as maintenance of redox balance during fermentations and bioremediations, have also been developed. This review briefly discusses the molecular mechanisms by which G. sulfurreducens and S. oneidensis exchange electrons with electrodes and then focuses on biotechnological applications of Geobacter and Shewanella spp. in microbial fuel cells and electrobiosynthesis as well as the future directions of this research area.
基金the National Natural Science Foundation of China (Nos. 21602150, 51763017, 51863012, 21861025, 51833004)Natural Science Foundation of Jiangxi Province in China (Nos. 20171ACB21012 and 2018ACB21022)the Innovation Fund Designated for Graduate Students of Nanchang University(No. CX2018028)
文摘In this study, a series of random conjugated polymers (PBDB-TBTn) as donors were designed and synthesized. In these polymers, benzodithiophene unit with thiophene conjugated side chains (BDT) are donor part, and two different content of benzo[1,2-c:4,5-c']dithiophene-4,8-dione (BDD) and difluorobenzothiadizole (BT) linked alkylthiophene are acceptor unit. Polymer solar cells (PSCs) were fabricated with ITIC as an acceptor, and over the power conversion efficiency (PCE) of 9%was obtained, with open circuit voltage (Voc) of 0.86 V, short-circuit current density (Jsc) of 16.84 mA/cm^2, and fill factor (FF) of 62.5%. These random conjugated polymers based solar cells are insensitive to solvent additives and thermal annealing. The performance of the device decreases gradually with the increasing of the proportion of fluorinated acceptor unit. The declining efficiency is due to the excessive fluorinated acceptor unit, which leads to over aggregated topography, destroys the effective charge transport pathways, and affects phase separation domain size between the donor and the acceptor. The phenomena are explained by the charge carrier recombination, atomic force microscope (AFM), and transmission electron microscope (TEM). These results indicate that proper addition of fluorinated acceptor units to build random copolymers can enhance the efficiency of organic photovoltaics toward additive-free and thermal annealing-free PSCs.
基金This work was supported by the National Key Research and Development Program(2018YFD1000800)the National Natural Science Foundation of China(31160398,31560563,31860568,32072559,and 32102370)+2 种基金the Key Research and Development Program of Gansu Province,China(21YF5WA096)the Natural Science Foundation of Gansu Province,China(1606RJZA073 and 1606RJZA077)the Research Fund of Higher Education of Gansu,China(2018C-14 and 2019B-082).We are grateful to members of our laboratory for helpful criticism and advice.
文摘Recognized as a pivotal developmental transition,flowering marks the continuation of a plant’s life cycle.Vernalization and pho-toperiod are two major flowering pathways orchestrating numerous florigenic signals.Methylation,including histone,DNA and RNA methylation,is one of the recent foci in plant development.Considerable studies reveal that methylation seems to show an increasing potential regulatory role in plant flowering via altering relevant gene expression without altering the genetic basis.However,little has been reviewed about whether and how methylation acts on vernalization-and photoperiod-induced flowering before and after FLOWERING LOCUS C(FLC)reactivation,what role RNA methylation plays in vernalization-and photoperiod-induced flowering,how methylation participates simultaneously in both vernalization-and photoperiod-induced flowering,the heritability of methylation memory under the vernalization/photoperiod pathway,and whether and how methylation replaces vernalization/photoinduction to regulate flowering.Our review provides insight about the crosstalk among the genetic control of the flowering gene network,methylation(methyltransferases/demethylases)and external signals(cold,light,sRNA and phytohormones)in vernalization and photoperiod pathways.The existing evidence that RNA methylation may play a potential regulatory role in vernalization-and photoperiod-induced flowering has been gathered and represented for the first time.This review speculates about and discusses the possibility of substituting methylation for vernalization and photoinduction to promote flowering.Current evidence is utilized to discuss the possibility of future methylation reagents becoming flowering regulators at the molecular level.
