Cis-regulatory elements regulate gene expression and play an essential role in the development and physiology of organisms.Many conserved non-coding sequences(CNSs)function as cis-regulatory elements.They control the ...Cis-regulatory elements regulate gene expression and play an essential role in the development and physiology of organisms.Many conserved non-coding sequences(CNSs)function as cis-regulatory elements.They control the development of various lineages.How-ever,predicting clade-wide cis-regulatory elements across several closely related species remains challenging.Based on the relationship between CNSs and cis-regulatory elements,we present a computational approach that predicts the clade-wide putative cis-regulatory elements in 12 Cucurbitaceae genomes.Using 12-way whole-genome alignment,we first obtained 632112 CNSs in Cucurbitaceae.Next,we identified 16552 Cucurbitaceae-wide cis-regulatory elements based on collinearity among all 12 Cucurbitaceae plants.Furthermore,we predicted 3271 potential regulatory pairs in the cucumber genome,of which 98 were verified using integrative RNA sequencing and ChIP sequencing datasets from samples collected during various fruit development stages.The CNSs,Cucurbitaceae-wide cis-regulatory elements,and their target genes are accessible at http://cmb.bnu.edu.cn/cisRCNEs_cucurbit/.These elements are valuable resources for functionally annotating CNSs and their regulatory roles in Cucurbitaceae genomes.展开更多
Security risks of flammability and explosion represent major problems with the use of conventional lithium rechargeable batteries using a liquid electrolyte.The application of solid-state electrolytes could effectivel...Security risks of flammability and explosion represent major problems with the use of conventional lithium rechargeable batteries using a liquid electrolyte.The application of solid-state electrolytes could effectively help to avoid these safety concerns.However,integrating the solid-state electrolytes into the all-solid-state lithium batteries is still a huge challenge mainly due to the high interfacial resistance present in the entire battery,especially at the interface between the cathode and the solid-state electrolyte pellet and the interfaces inside the cathode.Herein,recent progress made from investigations of cathode/solid-state electrolyte interfacial behaviors including the contact problem,the interlayer diffusion issue,the space-charge layer effect,and electrochemical compatibility is presented according to the classification of oxide-,sulfide-,and polymer-based solid-state electrolytes.We also propose strategies for the construction of ideal next-generation cathode/solid-state electrolyte interfaces with high room-temperature ionic conductivity,stable interfacial contact during long cycling,free formation of the space-charge region,and good compatibility with high-voltage cathodes.展开更多
The energy density of commercial lithium(Li)ion batteries with graphite anode is reaching the limit.It is believed that directly utilizing Li metal as anode without a host could enhance the battery’s energy density t...The energy density of commercial lithium(Li)ion batteries with graphite anode is reaching the limit.It is believed that directly utilizing Li metal as anode without a host could enhance the battery’s energy density to the maximum extent.However,the poor reversibility and infinite volume change of Li metal hinder the realistic implementation of Li metal in battery community.Herein,a commercially viable hybrid Li-ion/metal battery is realized by a coordinated strategy of symbiotic anode and prelithiated cathode.To be specific,a scalable template-removal method is developed to fabricate the porous graphite layer(PGL),which acts as a symbiotic host for Li ion intercalation and subsequent Li metal deposition due to the enhanced lithiophilicity and sufficient ion-conducting pathways.A continuous dissolution-deintercalation mechanism during delithiation process further ensures the elimination of dead Li.As a result,when the excess plating Li reaches 30%,the PGL could deliver an ultrahigh average Coulombic efficiency of 99.5% for 180 cycles with a capacity of 2.48 m Ah cm^(-2) in traditional carbonate electrolyte.Meanwhile,an air-stable recrystallized lithium oxalate with high specific capacity(514.3 m Ah g^(-1))and moderate operating potential(4.7-5.0 V)is introduced as a sacrificial cathode to compensate the initial loss and provide Li source for subsequent cycles.Based on the prelithiated cathode and initial Li-free symbiotic anode,under a practical-level3 m Ah capacity,the assembled hybrid Li-ion/metal full cell with a P/N ratio(capacity ratio of Li Ni_(0.8)Co_(0.1)Mn_(0.1)O_(2) to graphite)of 1.3exhibits significantly improved capacity retention after 300 cycles,indicating its great potential for high-energy-density Li batteries.展开更多
This article conducts a brief analysis of the factors that affect the quality safety of organic mango, and discusses the organic production measures for improving the quality and quality safety of mango, including the...This article conducts a brief analysis of the factors that affect the quality safety of organic mango, and discusses the organic production measures for improving the quality and quality safety of mango, including the choice of environment of place of origin, varieties and seedlings, fertilizers and fertilization, plant protection products and other production inputs. A test is carried out in 0.667 hm2 of base in Tianyang County, Baise City. Content of lead, arsenic and 14 kinds of pesticide residue such as BHC in the mango are not detected; the content of heavy metal such as mercury and cadmium is 0.001-0.006 mg/kg. Then the quality and quality safety indicators of organic mango are discussed, and finally the Guangxi local standards of organic mango products are developed.展开更多
Lithium(Li)metal is the ultimate anode choice for next generation high energy density batteries.However,the high nucleation energy barrier and nonuniform electric field distribution,as well as huge volume expansion,le...Lithium(Li)metal is the ultimate anode choice for next generation high energy density batteries.However,the high nucleation energy barrier and nonuniform electric field distribution,as well as huge volume expansion,lead to the uncontrollable growth of Li dendrites and poor utilization of Li metal,which hinders its practical application.Herein,titanium dioxide/cuprous oxide(TiO_(2)/Cu_(2)O)heterostructure is constructed on the rimous skeleton of Cu mesh,and the heterostructure decorated rimous Cu mesh(H-CM)can act as both current collector and host for dendrite-free Li metal anode.The TiO_(2)/Cu_(2)O heterostructure realizes selective Li nucleation by nano TiO_(2)and then induces fast and uniform Li conduction with the aid of heterostructure interface and nano Cu_(2)O contributing to dendrite-free Li deposition.While the internal and external space of rimous skeletons in H-CM is used to accommodate the deposited Li and buffer its volume change.Therefore,the cycling reversibility of the derived Li metal anode in H-CM is improved to a high Coulombic efficiency of 98.8%for more than 350 cycles at a current density of 1 mA·cm−2,and 1,000 h(equals to 500 cycles)stable repeated Li plating/stripping can be operated in a symmetric cell.Furthermore,full cells with limited Li anode and high loading LiFePO4 cathode present excellent cycling and rate performances.展开更多
Uncontrolled growth of lithium dendrite will lead to low Coulombic efficiency and poor cycle stability,which hinders the commercialization of lithium metal batteries.Herein,a novel modified lithium anode with reduced ...Uncontrolled growth of lithium dendrite will lead to low Coulombic efficiency and poor cycle stability,which hinders the commercialization of lithium metal batteries.Herein,a novel modified lithium anode with reduced graphene oxide conductive network containing trace lithiophilic phosphorus(P-rGO/Cu)is prepared by electrospraying technique combined with heat treatment process.The rGO layer has a concave and undulating conductive structure,which can significantly improve the effective electrical contact between lithium metal and the current collector,speed up the kinetics of interfacial electron transport and reaction,and improve the resistance of the negative electrode to the internal stress caused by volume change of the lithium,which is advantageous for the stability of the SEI film.The extremely small and uniformly distributed red phosphorus element avoids the volume change caused by lithiation to the maximum extent.Lithiophilic two-phase compound Li_(3)P obtained by alloying P with Li can directionally induce the homogeneous nucleation and dense deposition of lithium metal,address the issue of lithium dendrites and extend the cycle life of the batteries.The obtained P-rGO/Cu exhibits excellent electrochemical performance with an average Coulombic efficiency(CE)of 98%at a current density of 1 mA·cm^(−2) for 400 cycles,and the capacity retention rate of the full cell matched with lithium iron phosphate(LFP)is 83%after 400 cycles at 1C.展开更多
The overuse of antibiotics in animal agriculture and medicine has caused a series of potential threats to public health. Macleaya cordata is a medicinal plant species from the Papaveraceae family, providing a safe res...The overuse of antibiotics in animal agriculture and medicine has caused a series of potential threats to public health. Macleaya cordata is a medicinal plant species from the Papaveraceae family, providing a safe resource for the manufacture of antimicrobial feed additive for livestock. The active constituents from M. cordata are known to include benzylisoquinoline alkaloids (BIAs) such as sanguinarine (SAN) and chelerythrine (CHE), but their metabolic pathways have yet to be studied in this non-model plant. The active biosynthesis of SAN and CHE in M. cordata was first examined and confirmed by feeding ^13C-labeled tyrosine. To gain further insights, we de novo sequenced the whole genome of M. cordata, the first to be sequenced from the Papaveraceae family. The M. cordata genome covering 378 Mb encodes 22,328 predicted protein-coding genes with 43.5% being transposable elements. As a member of basal eudicot, M. cordata genome lacks the paleohexaploidy event that occurred in almost all eudicots. From the genomics data, a complete set of 16 metabolic genes for SAN and CHE biosynthesis was retrieved, and 14 of their biochemical activities were validated. These genomics and metabolic data show the conserved BIA metabolic pathways in M. cordata and provide the knowledge foundation for future productions of SAN and CHE by crop improvement or microbial pathway reconstruction.展开更多
Improving charge carriers separation to achieve high photoconversion efficiency in heterogeneous photocatalysts is highly desirable.Herein,heterostructured ZnS@CdS double-layered porous nanotubes(PNTs),in which the sp...Improving charge carriers separation to achieve high photoconversion efficiency in heterogeneous photocatalysts is highly desirable.Herein,heterostructured ZnS@CdS double-layered porous nanotubes(PNTs),in which the spatially separated reduction and oxidation reaction sites lie on the outer and inner shell,respectively,are fabricated through a robust self-template conversion strategy.After selective photo-deposition of Ni and CoO_x as dual cocatalysts,Ni nanoparticles as electron collectors and reduction reaction sites are loaded on the outer shell,while CoO_x nanoparticles as hole collectors and oxidation reaction sites are loaded on the inner shells.As a result,a novel CoO_x/ZnS@CdS/Ni photocatalyst is obtained and shows high visible-light-driven photocatalytic hydrogen production activity owing to the synergistic effect of self-template-derived thin mesoporous heterojunctions and photo-depositionderived spatially separated dual cocatalysts,which can significantly provide driving force for the ordered transfer of photogenerated electrons and holes toward opposite direction and promote the surface catalytic reaction.Additionally,the facile strategy can be broadened to the preparation of CoO_x/ZnSe@CdSe/NiPNTs with enhanced photocatalytic activity.展开更多
Aims The neutral theory of biodiversity provides a powerful framework for modeling macroecological patterns and interpreting species assemblages.However,there remain several unsolved problems,including the effect of r...Aims The neutral theory of biodiversity provides a powerful framework for modeling macroecological patterns and interpreting species assemblages.However,there remain several unsolved problems,including the effect of relaxing the assumption of strict neutrality to allow for empirically observed variation in vital rates and the‘problem of time’—empirically measured coexistence times are much shorter than the prediction of the strictly neutral drift model.Here,we develop a nearly neutral model that allows for differential birth and death rates of species.This model provides an approach to study species coexistence away from strict neutrality.Methods Based on Moran’s neutral model,which assumes all species in a community have the same competitive ability and have identical birth and death rates,we developed a model that includes birth–death trade-off but excludes speciation.This model describes a wide range of asymmetry from strictly neutral to nearly neutral to far from neutral and is useful for analyzing the effect of drift on species coexistence.Specifically,we analyzed the effects of the birth–death trade-off on the time and probability of species coexistence and quantified the loss of biodiversity(as measured by Simpson’s diversity)due to drift by varying species birth and death rates.Important Findings We found(i)a birth–death trade-off operating as an equalizing force driven by demographic stochasticity promotes the coexistence of nearly neutral species.Species near demographic trade-offs(i.e.fitness equivalence)can coexist even longer than that predicted by the strictly neutral model;(ii)the effect of birth rates on species coexistence is very similar to that of death rates,but their compensatory effects are not completely symmetric;(iii)ecological drift over time produces a march to fixation.Trade-off-based neutral communities lose diversity more slowly than the strictly neutral community,while non-neutral communities lose diversity much more rapidly;and(iv)nearly neutral systems have substantially shorter time of coexistence than that of neutral systems.This reduced time provides a promising solution to the problem of time.展开更多
Aims Much recent theory has focused on the role of neutral processes in assembling communities,but the basic assumption that all species are demographically identical has found little empirical support.Here,we show th...Aims Much recent theory has focused on the role of neutral processes in assembling communities,but the basic assumption that all species are demographically identical has found little empirical support.Here,we show that the framework of the current neutral theory can easily be generalized to incorporate species differences so long as fitness equivalence among individuals is maintained through trade-offs between birth and death.Methods Our theory development is based on a careful reformulation of the Moran model of metacommunity dynamics in terms of a non-linear one-step stochastic process,which is described by a master equation.Important Findings We demonstrate how fitness equalization through demographic trade-offs can generate significant macroecological diversity patterns,leading to a very different interpretation of the relation between Fisher’s a and Hubbell’s fundamental biodiversity number.Our model shows that equal fitness(not equal demographics)significantly promotes species diversity through strong selective sieving of community membership against high-mortality species,resulting in a positive association between species abundance and per capita death rate.An important implication of demographic trade-off is that it can partly explain the excessively high speciation rates predicted by the neutral theory of the stronger symmetry.Fitness equalization through demographic trade-offs generalizes neutral theory by considering heterospecific demographic difference,thus representing a significant step toward integrating the neutral and niche paradigms of biodiversity.展开更多
Phase field crystal (PFC) model is employed to simulate the process of growth of epitaxial layer on plane-convex substrate with a lattice mismatch and a small inclination angle. The variation of the systematic free ...Phase field crystal (PFC) model is employed to simulate the process of growth of epitaxial layer on plane-convex substrate with a lattice mismatch and a small inclination angle. The variation of the systematic free energy, the total atomic number of the epitaxial layer, and the effect of the curvature and the angle of the substrate are analyzed. The results show that when the surface of the substrate is plane, the free energy increases with the increase of the substrate inclination angle, and also the total atomic number of the epitaxial layer increases; while the surface of the substrate is convex, the free energy decreases with the increase of substrate angle and so also the total atomic number of the epitaxial layer decrease. This is the reason that the frontier of surface of epitaxial layer changes from the step bunching to the hill-and-valley facet structure with the increasing of the inclination angle of convex substrate. These results are in good agreement with the other method results.展开更多
基金supported by the National Natural Science Foundation of China(grant number:31571361).
文摘Cis-regulatory elements regulate gene expression and play an essential role in the development and physiology of organisms.Many conserved non-coding sequences(CNSs)function as cis-regulatory elements.They control the development of various lineages.How-ever,predicting clade-wide cis-regulatory elements across several closely related species remains challenging.Based on the relationship between CNSs and cis-regulatory elements,we present a computational approach that predicts the clade-wide putative cis-regulatory elements in 12 Cucurbitaceae genomes.Using 12-way whole-genome alignment,we first obtained 632112 CNSs in Cucurbitaceae.Next,we identified 16552 Cucurbitaceae-wide cis-regulatory elements based on collinearity among all 12 Cucurbitaceae plants.Furthermore,we predicted 3271 potential regulatory pairs in the cucumber genome,of which 98 were verified using integrative RNA sequencing and ChIP sequencing datasets from samples collected during various fruit development stages.The CNSs,Cucurbitaceae-wide cis-regulatory elements,and their target genes are accessible at http://cmb.bnu.edu.cn/cisRCNEs_cucurbit/.These elements are valuable resources for functionally annotating CNSs and their regulatory roles in Cucurbitaceae genomes.
基金National Natural Science Foundation of China(U2001220)the Local Innovative Research Teams Project of Guangdong Pearl River Talents Program(No.2017BT01N111)+1 种基金the Shenzhen Technical Plan Project(Nos.JCYJ20180508152210821,JCYJ20170817161221958,and JCYJ20180508152135822)the Shenzhen All-Solid-State Lithium Battery Electrolyte Engineering Research Center(XMHT20200203006).
文摘Security risks of flammability and explosion represent major problems with the use of conventional lithium rechargeable batteries using a liquid electrolyte.The application of solid-state electrolytes could effectively help to avoid these safety concerns.However,integrating the solid-state electrolytes into the all-solid-state lithium batteries is still a huge challenge mainly due to the high interfacial resistance present in the entire battery,especially at the interface between the cathode and the solid-state electrolyte pellet and the interfaces inside the cathode.Herein,recent progress made from investigations of cathode/solid-state electrolyte interfacial behaviors including the contact problem,the interlayer diffusion issue,the space-charge layer effect,and electrochemical compatibility is presented according to the classification of oxide-,sulfide-,and polymer-based solid-state electrolytes.We also propose strategies for the construction of ideal next-generation cathode/solid-state electrolyte interfaces with high room-temperature ionic conductivity,stable interfacial contact during long cycling,free formation of the space-charge region,and good compatibility with high-voltage cathodes.
基金The authors thank Mr Qin Peng Mong, Xiao Feng Li, Satoshi Tabata, Shusei Sato and Jun Yang for their help to conduct the experiment, and Dr Liang Huang for helpful revision of the manuscript. This research was financially supported by the National Natural Science Foundation of China (Grant No. 30430330).
基金the support by the Key-Area Research and Development Program of Guangdong Province(No.2020B090919003)the National Nature Science Foundation of China(Nos.51872157 and 52072208)+4 种基金the Shenzhen Technical Plan Project(Nos.JCYJ20170817161753629 and JCYJ20170412170911187)the Special Fund Project for Strategic Emerging Industry Development of Shenzhen(No.20170428145209110)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(No.2017BT01N111)the Support Plan for Shenzhen Manufacturing Innovation Center(No.20200627215553988)the Key projects for core technology research of Dongguan(No.2019622119003)。
文摘The energy density of commercial lithium(Li)ion batteries with graphite anode is reaching the limit.It is believed that directly utilizing Li metal as anode without a host could enhance the battery’s energy density to the maximum extent.However,the poor reversibility and infinite volume change of Li metal hinder the realistic implementation of Li metal in battery community.Herein,a commercially viable hybrid Li-ion/metal battery is realized by a coordinated strategy of symbiotic anode and prelithiated cathode.To be specific,a scalable template-removal method is developed to fabricate the porous graphite layer(PGL),which acts as a symbiotic host for Li ion intercalation and subsequent Li metal deposition due to the enhanced lithiophilicity and sufficient ion-conducting pathways.A continuous dissolution-deintercalation mechanism during delithiation process further ensures the elimination of dead Li.As a result,when the excess plating Li reaches 30%,the PGL could deliver an ultrahigh average Coulombic efficiency of 99.5% for 180 cycles with a capacity of 2.48 m Ah cm^(-2) in traditional carbonate electrolyte.Meanwhile,an air-stable recrystallized lithium oxalate with high specific capacity(514.3 m Ah g^(-1))and moderate operating potential(4.7-5.0 V)is introduced as a sacrificial cathode to compensate the initial loss and provide Li source for subsequent cycles.Based on the prelithiated cathode and initial Li-free symbiotic anode,under a practical-level3 m Ah capacity,the assembled hybrid Li-ion/metal full cell with a P/N ratio(capacity ratio of Li Ni_(0.8)Co_(0.1)Mn_(0.1)O_(2) to graphite)of 1.3exhibits significantly improved capacity retention after 300 cycles,indicating its great potential for high-energy-density Li batteries.
基金Supported by Scientific and Technological Project of Guangxi Provincial Department of Science and Technology(2007105014)
文摘This article conducts a brief analysis of the factors that affect the quality safety of organic mango, and discusses the organic production measures for improving the quality and quality safety of mango, including the choice of environment of place of origin, varieties and seedlings, fertilizers and fertilization, plant protection products and other production inputs. A test is carried out in 0.667 hm2 of base in Tianyang County, Baise City. Content of lead, arsenic and 14 kinds of pesticide residue such as BHC in the mango are not detected; the content of heavy metal such as mercury and cadmium is 0.001-0.006 mg/kg. Then the quality and quality safety indicators of organic mango are discussed, and finally the Guangxi local standards of organic mango products are developed.
基金supported by the National Natural Science Foundation of China(Nos.51872157 and 52072208)Fundamental Research Project of Shenzhen(No.JCYJ20190808153609561)+1 种基金Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(No.2017BT01N111)Support Plan for Shenzhen Manufacturing Innovation Center(No.20200627215553988).
文摘Lithium(Li)metal is the ultimate anode choice for next generation high energy density batteries.However,the high nucleation energy barrier and nonuniform electric field distribution,as well as huge volume expansion,lead to the uncontrollable growth of Li dendrites and poor utilization of Li metal,which hinders its practical application.Herein,titanium dioxide/cuprous oxide(TiO_(2)/Cu_(2)O)heterostructure is constructed on the rimous skeleton of Cu mesh,and the heterostructure decorated rimous Cu mesh(H-CM)can act as both current collector and host for dendrite-free Li metal anode.The TiO_(2)/Cu_(2)O heterostructure realizes selective Li nucleation by nano TiO_(2)and then induces fast and uniform Li conduction with the aid of heterostructure interface and nano Cu_(2)O contributing to dendrite-free Li deposition.While the internal and external space of rimous skeletons in H-CM is used to accommodate the deposited Li and buffer its volume change.Therefore,the cycling reversibility of the derived Li metal anode in H-CM is improved to a high Coulombic efficiency of 98.8%for more than 350 cycles at a current density of 1 mA·cm−2,and 1,000 h(equals to 500 cycles)stable repeated Li plating/stripping can be operated in a symmetric cell.Furthermore,full cells with limited Li anode and high loading LiFePO4 cathode present excellent cycling and rate performances.
基金This study was financially supported by the Key-Area Research and Development Program of Guangdong Province(No.2020B090919003)the National Natural Science Foundation of China(Nos.52261160384,51872157 and 52072208)+2 种基金the Fundamental Research Project of Shenzhen(No.JCYJ20190808153609561)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(No.2017BT01N111)the Support Plan for Shenzhen Manufacturing Innovation Center(No.20200627215553988).
文摘Uncontrolled growth of lithium dendrite will lead to low Coulombic efficiency and poor cycle stability,which hinders the commercialization of lithium metal batteries.Herein,a novel modified lithium anode with reduced graphene oxide conductive network containing trace lithiophilic phosphorus(P-rGO/Cu)is prepared by electrospraying technique combined with heat treatment process.The rGO layer has a concave and undulating conductive structure,which can significantly improve the effective electrical contact between lithium metal and the current collector,speed up the kinetics of interfacial electron transport and reaction,and improve the resistance of the negative electrode to the internal stress caused by volume change of the lithium,which is advantageous for the stability of the SEI film.The extremely small and uniformly distributed red phosphorus element avoids the volume change caused by lithiation to the maximum extent.Lithiophilic two-phase compound Li_(3)P obtained by alloying P with Li can directionally induce the homogeneous nucleation and dense deposition of lithium metal,address the issue of lithium dendrites and extend the cycle life of the batteries.The obtained P-rGO/Cu exhibits excellent electrochemical performance with an average Coulombic efficiency(CE)of 98%at a current density of 1 mA·cm^(−2) for 400 cycles,and the capacity retention rate of the full cell matched with lithium iron phosphate(LFP)is 83%after 400 cycles at 1C.
基金This work was supported by National Natural Science Foundation of China (31200615, 31600238), Postgraduate Research and Innovation Project of Hunan Province (CX2014B302), National Key Laboratory Cultivation Base Construction Project (15KFXM09), the National Science-Technology Support Plan Projects of China (2012BAI29B04), The talent introduction Science Foundation of Hunan Agricultural University (13YJ09), and the Natural Science Foundation of Hunan Province (2016JJ4040).
文摘The overuse of antibiotics in animal agriculture and medicine has caused a series of potential threats to public health. Macleaya cordata is a medicinal plant species from the Papaveraceae family, providing a safe resource for the manufacture of antimicrobial feed additive for livestock. The active constituents from M. cordata are known to include benzylisoquinoline alkaloids (BIAs) such as sanguinarine (SAN) and chelerythrine (CHE), but their metabolic pathways have yet to be studied in this non-model plant. The active biosynthesis of SAN and CHE in M. cordata was first examined and confirmed by feeding ^13C-labeled tyrosine. To gain further insights, we de novo sequenced the whole genome of M. cordata, the first to be sequenced from the Papaveraceae family. The M. cordata genome covering 378 Mb encodes 22,328 predicted protein-coding genes with 43.5% being transposable elements. As a member of basal eudicot, M. cordata genome lacks the paleohexaploidy event that occurred in almost all eudicots. From the genomics data, a complete set of 16 metabolic genes for SAN and CHE biosynthesis was retrieved, and 14 of their biochemical activities were validated. These genomics and metabolic data show the conserved BIA metabolic pathways in M. cordata and provide the knowledge foundation for future productions of SAN and CHE by crop improvement or microbial pathway reconstruction.
基金supported by the National Natural Science Foundation of China(21422104)the Natural Science Foundation of Tianjin City(17JCJQJC44700 and 16JCZDJC30600)
文摘Improving charge carriers separation to achieve high photoconversion efficiency in heterogeneous photocatalysts is highly desirable.Herein,heterostructured ZnS@CdS double-layered porous nanotubes(PNTs),in which the spatially separated reduction and oxidation reaction sites lie on the outer and inner shell,respectively,are fabricated through a robust self-template conversion strategy.After selective photo-deposition of Ni and CoO_x as dual cocatalysts,Ni nanoparticles as electron collectors and reduction reaction sites are loaded on the outer shell,while CoO_x nanoparticles as hole collectors and oxidation reaction sites are loaded on the inner shells.As a result,a novel CoO_x/ZnS@CdS/Ni photocatalyst is obtained and shows high visible-light-driven photocatalytic hydrogen production activity owing to the synergistic effect of self-template-derived thin mesoporous heterojunctions and photo-depositionderived spatially separated dual cocatalysts,which can significantly provide driving force for the ordered transfer of photogenerated electrons and holes toward opposite direction and promote the surface catalytic reaction.Additionally,the facile strategy can be broadened to the preparation of CoO_x/ZnSe@CdSe/NiPNTs with enhanced photocatalytic activity.
基金National Natural Science Foundation of China(D.Y.Z.and K.L.)Ministry of Science and Technology of China(D.Y.Z.and K.L.)+2 种基金Geomatics for Informed Decisions Network of Canada(F.H.)Natural Sciences and Engineering Research Council of Canada(F.L.)University of Alberta International(the China-UofA Joint Research Lab program).
文摘Aims The neutral theory of biodiversity provides a powerful framework for modeling macroecological patterns and interpreting species assemblages.However,there remain several unsolved problems,including the effect of relaxing the assumption of strict neutrality to allow for empirically observed variation in vital rates and the‘problem of time’—empirically measured coexistence times are much shorter than the prediction of the strictly neutral drift model.Here,we develop a nearly neutral model that allows for differential birth and death rates of species.This model provides an approach to study species coexistence away from strict neutrality.Methods Based on Moran’s neutral model,which assumes all species in a community have the same competitive ability and have identical birth and death rates,we developed a model that includes birth–death trade-off but excludes speciation.This model describes a wide range of asymmetry from strictly neutral to nearly neutral to far from neutral and is useful for analyzing the effect of drift on species coexistence.Specifically,we analyzed the effects of the birth–death trade-off on the time and probability of species coexistence and quantified the loss of biodiversity(as measured by Simpson’s diversity)due to drift by varying species birth and death rates.Important Findings We found(i)a birth–death trade-off operating as an equalizing force driven by demographic stochasticity promotes the coexistence of nearly neutral species.Species near demographic trade-offs(i.e.fitness equivalence)can coexist even longer than that predicted by the strictly neutral model;(ii)the effect of birth rates on species coexistence is very similar to that of death rates,but their compensatory effects are not completely symmetric;(iii)ecological drift over time produces a march to fixation.Trade-off-based neutral communities lose diversity more slowly than the strictly neutral community,while non-neutral communities lose diversity much more rapidly;and(iv)nearly neutral systems have substantially shorter time of coexistence than that of neutral systems.This reduced time provides a promising solution to the problem of time.
基金National Natural Science Foundation of China(31030014,31121003)State Key Basic Research and Development Plan(2007CB106800 and 2010CB434800)+1 种基金Natural Sciences and Engineering Research Council(Canada)University of Alberta International(the China-UofA Joint Research Lab program).
文摘Aims Much recent theory has focused on the role of neutral processes in assembling communities,but the basic assumption that all species are demographically identical has found little empirical support.Here,we show that the framework of the current neutral theory can easily be generalized to incorporate species differences so long as fitness equivalence among individuals is maintained through trade-offs between birth and death.Methods Our theory development is based on a careful reformulation of the Moran model of metacommunity dynamics in terms of a non-linear one-step stochastic process,which is described by a master equation.Important Findings We demonstrate how fitness equalization through demographic trade-offs can generate significant macroecological diversity patterns,leading to a very different interpretation of the relation between Fisher’s a and Hubbell’s fundamental biodiversity number.Our model shows that equal fitness(not equal demographics)significantly promotes species diversity through strong selective sieving of community membership against high-mortality species,resulting in a positive association between species abundance and per capita death rate.An important implication of demographic trade-off is that it can partly explain the excessively high speciation rates predicted by the neutral theory of the stronger symmetry.Fitness equalization through demographic trade-offs generalizes neutral theory by considering heterospecific demographic difference,thus representing a significant step toward integrating the neutral and niche paradigms of biodiversity.
基金Acknowledgements This work was supported by the National Natural Science Foundation of China (Grant No. 51161003), the Natural Science Foundation of Guangxi Province (Grant No. 2012GXNSFDA053001) and Ministry-Province jointly-constructed cultivation base for State Key Laboratory of Processing for non-ferrous metal and featured materials, Guangxi Zhuang Autonomous Region (Grant No. GXKF J 12 -01 ).
文摘Phase field crystal (PFC) model is employed to simulate the process of growth of epitaxial layer on plane-convex substrate with a lattice mismatch and a small inclination angle. The variation of the systematic free energy, the total atomic number of the epitaxial layer, and the effect of the curvature and the angle of the substrate are analyzed. The results show that when the surface of the substrate is plane, the free energy increases with the increase of the substrate inclination angle, and also the total atomic number of the epitaxial layer increases; while the surface of the substrate is convex, the free energy decreases with the increase of substrate angle and so also the total atomic number of the epitaxial layer decrease. This is the reason that the frontier of surface of epitaxial layer changes from the step bunching to the hill-and-valley facet structure with the increasing of the inclination angle of convex substrate. These results are in good agreement with the other method results.