Foeused on the lack of proper organization for patterns in the development of pattern based software, a POMSDP model with layered tree structure for organizing patterns during the process of development was put torwar...Foeused on the lack of proper organization for patterns in the development of pattern based software, a POMSDP model with layered tree structure for organizing patterns during the process of development was put torward. The model and its interrelated eoneepts were strictly defined and introduced by applying the theory of set, symbolie logic and pattern, which ensures the correctness, maturity and expansibility of the model. The expansibility of the model was discussed mainly. The basic realization and the application in the automatic query system were presented. Based on the existing software development methods, the POMSDP model resolves the problem of chaos in the application of patterns, strengthens the controllability of the system, and facilitates the improvement, maintenance, expansion, and especially the reengineering of the software system.展开更多
The growth process of three-dimensional growth mode(3D) switching to two-dimensional growth mode (2D) is investigated when GaN films are grown on cone-shaped patterned sapphire substrates by metal-organic chemical...The growth process of three-dimensional growth mode(3D) switching to two-dimensional growth mode (2D) is investigated when GaN films are grown on cone-shaped patterned sapphire substrates by metal-organic chemical vapor deposition.The growth condition of the 3D-2D growth process is optimized to reduce the threading dislocation density(TDD).It is found that the condition of the 3D layer is critical.The 3D layer keeps growing under the conditions of lowⅤ/Ⅲratio,low temperature,and high pressure until its thickness is comparable to the height of the cone-shaped patterns.Then the 3D layer surrounds the cone-shaped patterns and has inclined side facets and a top(0001) plane.In the following 2D-growth process,inclined side facets coalesce quickly and the interaction of TDs with the side facets causes the TDs to bend over.As a result,the TDD of GaN films can decrease to 1×10~8 cm^(-2),giving full-width at half maximum values of 211 and 219 arcsec for(002) and(102) omega scans, respectively.展开更多
Plant growth and development involve the specification and regeneration of stem cell niches(SCNs).Although plants are exposed to disparate environmental conditions,how environmental cues affect developmental programs ...Plant growth and development involve the specification and regeneration of stem cell niches(SCNs).Although plants are exposed to disparate environmental conditions,how environmental cues affect developmental programs and stem cells is not well understood.Root stem cells are accommodated in meristems in SCNs around the quiescent center(QC),which maintains their activity.Using a combination of genetics and confocal microscopy to trace morphological defects and correlate them with changes in gene expression and protein levels,we show that the cold-induced transcription factor(TF)C-REPEAT BINDING FACTOR 3(CBF3),which has previously been associated with cold acclimation,regulates root development,stem cell activity,and regeneration.CBF3 is integrated into the SHORT-ROOT(SHR)regulatory network,forming a feedback loop that maintains SHR expression.CBF3 is primarily expressed in the root endodermis,whereas the CBF3 protein is localized to other meristematic tissues,including root SCNs.Complementation of cbf3-1 using a wild-type CBF3 gene and a CBF3 fusion with reduced mobility show that CBF3 movement capacity is required for SCN patterning and regulates root growth.Notably,cold induces CBF3,affecting QC activity.Furthermore,exposure to moderate cold around 10℃–12℃promotes root regeneration and QC respecification in a CBF3-dependent manner during the recuperation period.By contrast,CBF3 does not appear to regulate stem cell survival,which has been associated with recuperation from more acute cold(-4℃).We propose a role for CBF3 in mediating the molecular interrelationships among the cold response,stem cell activity,and development.展开更多
The spatial information of literature refers to the representation of physical or conscious space in literary works,including position,shape,structure,features,and relationships.The spatial information organization an...The spatial information of literature refers to the representation of physical or conscious space in literary works,including position,shape,structure,features,and relationships.The spatial information organization and its method are essential to the whole process of literature production,circulation,acceptance,and reproduction,which is conducive to a deeper exploration of the aesthetic essence of literature in the information era.Taking the organization of spatial information in science fiction as an example,this paper investigates the way of interaction between informatics and literature,explores the function of spatial information in the narrative of science fiction,and discovers digital humanistic laws of literary information organization.This study finds that the spatial information of early science fiction is organized in horizontal,vertical,axial,and causal modes;in the era of digital humanities,influenced by information technology such as the internet,virtual reality,and artificial intelligence,literary space has experienced revolutions characteristic of time-space integration,boundary dissolution,dimensional change,and virtualization;the spatial information organization of contemporary science fiction adopts nested,reticulated,parallel,interactive,and reverse patterns;on the whole,it is featured with fluidity,chaos,correlation,and mutation,creating a unique digital humanistic spectacle.展开更多
Over the past few decades genetic engineering has been applied to improve cotton breeding. Agrobacterium medicated transformation is nowadays widely used as an efficient approach to introduce exogenous genes into cott...Over the past few decades genetic engineering has been applied to improve cotton breeding. Agrobacterium medicated transformation is nowadays widely used as an efficient approach to introduce exogenous genes into cotton for genetically modified organisms. However, it still needs to be improved for better transformation efficiency and higher embryogenic callus induction ratios. To research further the difference of mechanisms for morphogenesis between embryogenic callus and non-embryogenic callus, we carried out a systematical study on the histological and cellular ultrastructure of Agrobacterium transformed calli. Results showed that the embryogenic callus developed nodule-like structures, which were formed by small, tightly packed, hemispherical cells. The surface of some embryogenic callus was covered with a fibrilar-like structure named extracellular matrix. The cells of embryogenic calli had similar morphological characteristics. Organelles of embryogenic callus cells were located near the nucleus, and chloroplasts degraded to proplastid-like structures with some starch grains. In contrast, the non-embryogenic calli were covered by oval or sphere cells or small clusters of cells. It was observed that cells had vacuolation of cytoplasm and plastids with a well organized endomembrane system. This study aims to understand the mechanisms of embryogenic callus morphogenesis and to improve the efficiency of cotton transformation in future.展开更多
In the past 20-30 years, developmental biologists have made tremendous progress in identifying genes required for the specifica-tion of individual cell types of an organ and in describing how they interact in genetic ...In the past 20-30 years, developmental biologists have made tremendous progress in identifying genes required for the specifica-tion of individual cell types of an organ and in describing how they interact in genetic networks. In comparison, very little is known about the mechanisms that regulate tissue polarity and overall organ patterning. Gynoecia and fruits from members of the Brassicaceae family of flowering plants provide excellent model systems to study organ patterning and tissue specification because they become partitioned into distinct domains whose formation is determined by polarity establishment both at a cellular and whole tissue level. Interactions among key regulators of Arabidopsis gynoecium and fruit development have revealed a network of upstream transcription factor activities required for such tissue differentiation. Regulation of the plant hormone auxin is emerging as both an immediate downstream output and input of these activities, and here we aim to provide an overview of the current knowledge regarding the link between auxin and female reproductive development in plants. In this review, we will also demonstrate how available data can be exploited in a mathematical modeling approach to reveal and understand the feedback regulatory circuits that underpin the polarity establishment, necessary to guide auxin flows.展开更多
文摘Foeused on the lack of proper organization for patterns in the development of pattern based software, a POMSDP model with layered tree structure for organizing patterns during the process of development was put torward. The model and its interrelated eoneepts were strictly defined and introduced by applying the theory of set, symbolie logic and pattern, which ensures the correctness, maturity and expansibility of the model. The expansibility of the model was discussed mainly. The basic realization and the application in the automatic query system were presented. Based on the existing software development methods, the POMSDP model resolves the problem of chaos in the application of patterns, strengthens the controllability of the system, and facilitates the improvement, maintenance, expansion, and especially the reengineering of the software system.
文摘The growth process of three-dimensional growth mode(3D) switching to two-dimensional growth mode (2D) is investigated when GaN films are grown on cone-shaped patterned sapphire substrates by metal-organic chemical vapor deposition.The growth condition of the 3D-2D growth process is optimized to reduce the threading dislocation density(TDD).It is found that the condition of the 3D layer is critical.The 3D layer keeps growing under the conditions of lowⅤ/Ⅲratio,low temperature,and high pressure until its thickness is comparable to the height of the cone-shaped patterns.Then the 3D layer surrounds the cone-shaped patterns and has inclined side facets and a top(0001) plane.In the following 2D-growth process,inclined side facets coalesce quickly and the interaction of TDs with the side facets causes the TDs to bend over.As a result,the TDD of GaN films can decrease to 1×10~8 cm^(-2),giving full-width at half maximum values of 211 and 219 arcsec for(002) and(102) omega scans, respectively.
基金funded by the Ministerio de Ciencia e Innovación(MICIN)of Spain and ERDF(grants PID2019-111523GB-I00 and PID2022-140719NB-I00 to M.A.M.-R.)the"Severo Ochoa Program for Centres of Excellence in R&D"from the Agencia Estatal de Investigación of Spain(AEI)(grant SEV-2016-06722017-2021)+2 种基金MICIN/AEI/10.13039/501100011033(grant CEX2020-000999-S)to M.A.M.-R.,P.P.-G.,M.P.,J.C.d.P.,and K.W.through Centro de Biotecnología y Genómica de Plantassupported by an FPI contract from MICIN(BES-2014-068852),P.P.-G.by a Juan de la Cierva contract from MICIN(FJCI-2015-24905)and Programa Atraccion Talento from Comunidad de Madrid(2017-T2/BIO-3453)J.C.by a Juan de la Cierva contract from AEI(FJCI-2016-28607),K.W.by program PGC2018-093387-A-I00 from MICIN,and O.P.by a postdoctoral contract associated with SEV-2016-0672.
文摘Plant growth and development involve the specification and regeneration of stem cell niches(SCNs).Although plants are exposed to disparate environmental conditions,how environmental cues affect developmental programs and stem cells is not well understood.Root stem cells are accommodated in meristems in SCNs around the quiescent center(QC),which maintains their activity.Using a combination of genetics and confocal microscopy to trace morphological defects and correlate them with changes in gene expression and protein levels,we show that the cold-induced transcription factor(TF)C-REPEAT BINDING FACTOR 3(CBF3),which has previously been associated with cold acclimation,regulates root development,stem cell activity,and regeneration.CBF3 is integrated into the SHORT-ROOT(SHR)regulatory network,forming a feedback loop that maintains SHR expression.CBF3 is primarily expressed in the root endodermis,whereas the CBF3 protein is localized to other meristematic tissues,including root SCNs.Complementation of cbf3-1 using a wild-type CBF3 gene and a CBF3 fusion with reduced mobility show that CBF3 movement capacity is required for SCN patterning and regulates root growth.Notably,cold induces CBF3,affecting QC activity.Furthermore,exposure to moderate cold around 10℃–12℃promotes root regeneration and QC respecification in a CBF3-dependent manner during the recuperation period.By contrast,CBF3 does not appear to regulate stem cell survival,which has been associated with recuperation from more acute cold(-4℃).We propose a role for CBF3 in mediating the molecular interrelationships among the cold response,stem cell activity,and development.
文摘The spatial information of literature refers to the representation of physical or conscious space in literary works,including position,shape,structure,features,and relationships.The spatial information organization and its method are essential to the whole process of literature production,circulation,acceptance,and reproduction,which is conducive to a deeper exploration of the aesthetic essence of literature in the information era.Taking the organization of spatial information in science fiction as an example,this paper investigates the way of interaction between informatics and literature,explores the function of spatial information in the narrative of science fiction,and discovers digital humanistic laws of literary information organization.This study finds that the spatial information of early science fiction is organized in horizontal,vertical,axial,and causal modes;in the era of digital humanities,influenced by information technology such as the internet,virtual reality,and artificial intelligence,literary space has experienced revolutions characteristic of time-space integration,boundary dissolution,dimensional change,and virtualization;the spatial information organization of contemporary science fiction adopts nested,reticulated,parallel,interactive,and reverse patterns;on the whole,it is featured with fluidity,chaos,correlation,and mutation,creating a unique digital humanistic spectacle.
基金Supported by the State Key Basic Research and Development Plan of China(2004CB117305)
文摘Over the past few decades genetic engineering has been applied to improve cotton breeding. Agrobacterium medicated transformation is nowadays widely used as an efficient approach to introduce exogenous genes into cotton for genetically modified organisms. However, it still needs to be improved for better transformation efficiency and higher embryogenic callus induction ratios. To research further the difference of mechanisms for morphogenesis between embryogenic callus and non-embryogenic callus, we carried out a systematical study on the histological and cellular ultrastructure of Agrobacterium transformed calli. Results showed that the embryogenic callus developed nodule-like structures, which were formed by small, tightly packed, hemispherical cells. The surface of some embryogenic callus was covered with a fibrilar-like structure named extracellular matrix. The cells of embryogenic calli had similar morphological characteristics. Organelles of embryogenic callus cells were located near the nucleus, and chloroplasts degraded to proplastid-like structures with some starch grains. In contrast, the non-embryogenic calli were covered by oval or sphere cells or small clusters of cells. It was observed that cells had vacuolation of cytoplasm and plastids with a well organized endomembrane system. This study aims to understand the mechanisms of embryogenic callus morphogenesis and to improve the efficiency of cotton transformation in future.
基金supported by the UK Biological and Biotechnology Research Council (BBSRC) via grant BB/J004553/1 to the John Innes CentreV. A. G. and L. φ . by BBSRC responsive mode grant BB/K008617/1V. A. G. acknowledges support from the Royal Society Dorothy Hodgkin fellowship
文摘In the past 20-30 years, developmental biologists have made tremendous progress in identifying genes required for the specifica-tion of individual cell types of an organ and in describing how they interact in genetic networks. In comparison, very little is known about the mechanisms that regulate tissue polarity and overall organ patterning. Gynoecia and fruits from members of the Brassicaceae family of flowering plants provide excellent model systems to study organ patterning and tissue specification because they become partitioned into distinct domains whose formation is determined by polarity establishment both at a cellular and whole tissue level. Interactions among key regulators of Arabidopsis gynoecium and fruit development have revealed a network of upstream transcription factor activities required for such tissue differentiation. Regulation of the plant hormone auxin is emerging as both an immediate downstream output and input of these activities, and here we aim to provide an overview of the current knowledge regarding the link between auxin and female reproductive development in plants. In this review, we will also demonstrate how available data can be exploited in a mathematical modeling approach to reveal and understand the feedback regulatory circuits that underpin the polarity establishment, necessary to guide auxin flows.