500 research outputs found

    Design and Realization of Automatic Warehouse Based on S7-1500PLC

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    In order to improve the efficiency of automatic warehouse control system,the experimental platform of stereoscopic warehouse with s7-1500plc is designed.The manipulator is driven by stepper motor and servo motor to realize x,y and Z three-axis space motion.The material transmission system is built by general-purpose G120 inverter. HMI KTP700 realizes control and status monitoring.The materials are identified and classified by RFID sensor and other sensors.TIAV15 software build PROFINET communication and PROFIBUS communication network.Using the GRAPH language programming can improve the visualization degree of application and solve the complex problems of program design and debugging of the warehouse control system.Through the design of hardware and software,a set of complete control system design scheme is formed,which has high practical value and provides an excellent teaching and experiment platform for the intelligent storage system

    Knowledge Modeling for Developing Program Planning Agents

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    This paper describes a method of domain knowledge modeling for program planning and scheduling in intelligent e-Learning advising systems, focusing on the modeling and representation of precedence relations among course learning objects encoded in model curricular and the representation of domain experts’ knowledge using Petri nets formalism and a XML-based markup language. We developed a Web-based program model editor

    Characterization of a Lymphoid Organ Specific Anti-lipopolysaccharide Factor From Shrimp Reveals Structure-Activity Relationship of the LPS-Binding Domain

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    Anti-lipopolysaccharide factor (ALF) is a kind of important antimicrobial peptides with broad-spectrum antimicrobial activities. The LPS-binding domain (LBD) contributes to the major antimicrobial activity of ALF. However, LBDs from different ALFs share low sequence similarity. The general character of LBDs needs to be elucidated to understand the molecular mechanism of their function and facilitate LBD-original drug design. Here we identified a lymphoid organ specifically expressed ALF, designated as FcALF8, from the Chinese shrimp Fenneropenaeus chinensis. The synthetic LBD peptide of FcALF8 (LBD8) showed strong antibacterial activities to the pathogenic Vibrio, such as Vibrio alginolyticus, Vibrio harveyi, and Photobacterium damselae with a MIC value of 0.5–1, 1–2, and 1–2 ÎŒM, respectively. FcALF8 knock-down using dsRNA led to significant increase of the viable bacteria in the lymphoid organ and hepatopancreas of shrimp upon V. harveyi infection. On the contrary, the proliferation of V. harveyi in the shrimp lymphoid organ and hepatopancreas significantly decreased after infected by LBD8 pre-incubated V. harveyi. Sequence alignments showed that the LBDs from 39 ALFs shared only two identical cysteine residues. However, 17 of the total 22 LBD residues showed high similarity when the amino acids were classified into hydrophobic and hydrophilic ones. A further activity analysis on modified LBD8 peptides showed that the antibacterial activity of LBD8 was lost after linearization and apparently weakened after changing the amino acid property at certain positions. The data indicated that the disulfide bond and amino acid property contributed to the conservation of the functional domain. To the best of our knowledge, this is the first identified ALFs specifically expressed in the lymphoid organ of shrimp with strong antibacterial activity. The present data will give creative instructions for the design of LBD-originated antimicrobial agents

    Identification of Functional Gene Modules Associated With STAT-Mediated Antiviral Responses to White Spot Syndrome Virus in Shrimp

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    White spot syndrome virus (WSSV) is one of the major threats to shrimp aquaculture. It has been found that the signal transducer and activator of transcription (STAT) protein plays an important role in the antiviral immunity of shrimp with a WSSV infection. However, the mechanism that underlies the STAT-mediated antiviral responses in shrimp, against WSSV infection, remains unclear. In this work, based on the gene expression profiles of shrimp with an injection of WSSV and STAT double strand RNA (dsRNA), we constructed a gene co-expression network for shrimp and identified the gene modules that are possibly responsible for STAT-mediated antiviral responses. These gene modules are found enriched in the regulation of the viral process, JAK-STAT cascade and the regulation of immune effector process pathways. The gene modules identified here provide insights into the molecular mechanism that underlies the STAT-mediated antiviral response of shrimp, against WSSV

    An intelligent agent for adapting and delivering electronic course materials to mobile learners

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    The concept of mobile learning is often defined as learning that takes place with the help of mobile devices to access course materials; however, these devices operate in different ways and have different capabilities. To make course materials available on these mobile devices as well as on desktop systems, a software program is required to allow course material to be delivered in heterogeneous computing platforms. Because of these heterogeneous computing platforms, some course materials may not be in a format that different mobile devices would accept. This project developed an intelligent software agent capable of adapting to the heterogeneous mobile computing environment. The agent can search for a conversion tool according to the desired format and convert the course materials automatically. The agent is able to understand mobile clients’ capabilities. In order for the server to know what type of course material the client wishes to receive, the client needs to feed information on the software and hardware capabilities of the device to the server. However, devices do not normally carry any information about their capabilities. We have chosen the Resource Description Framework (RDF) represented Composite Capabilities/Preferences Profile (CC/PP) promoted by the W3C to describe the device capabilities and user preferences

    Transcriptome analysis of <em>Litopenaeus vannamei</em> during the early stage of limb regeneration process

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    Regeneration is a process in which organisms regrow new tissues or organs at the injury site, which has attracted the attention of many scientists and nonscientists. However, the underlying molecular mechanisms of regeneration after autotomy are largely unknown. In this study, we conducted RNA-seq sequencing on regenerated limb bud tissues of *Litopenaeus vannamei* at 0 hours post autotomy (0 hpa), 12 hours post autotomy (12 hpa), and 24 hours post autotomy (24 hpa). A total of 2,192 differentially expressed genes related to energy metabolism, transcription and translation, and epidermis development were identified between 0 hpa and 12 hpa, such as triosephosphate isomerase A, triosephosphate isomerase B, and zinc finger protein 367 that is upregulated in 12 hpa. Between 12 hpa and 24 hpa, 1,447 differentially expressed genes were identified that were related to cuticle development and energy metabolism, such as cuticle protein 6, which is upregulated in 24 hpa, and triosephosphate isomerase is downregulated in 24 hpa. The results indicated that energy metabolism, transcription and translation, epidermal formation, and chitin metabolism processes are involved during the early stage of limb regeneration. This study provides basic knowledge for investigating the molecular mechanisms associated with limb regeneration in crustaceans at the early regeneration stage

    CRISPR/Cas9-mediated gene mutation of EcIAG leads to sex reversal in the male ridgetail white prawn Exopalaemon carinicauda

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    In the culture of crustaceans, most species show sexual dimorphism. Monosex culture is an effective approach to achieve high yield and economic value, especially for decapods of high value. Previous studies have developed some sex control strategies such as manual segregation, manipulation of male androgenic gland and knockdown of the male sexual differentiation switch gene encoding insulin-like androgenic gland hormone (IAG) in decapods. However, these methods could not generate hereditable changes. Genetic manipulation to achieve sex reversal individuals is absent up to now. In the present study, the gene encoding IAG (EcIAG) was identified in the ridgetail white prawn Exopalaemon carinicauda. Sequence analysis showed that EcIAG encoded conserved amino acid structure like IAGs in other decapod species. CRISPR/Cas9-mediated genome editing technology was used to knock out EcIAG. Two sgRNAs targeting the second exon of EcIAG were designed and microinjected into the prawn zygotes or the embryos at the first cleavage with commercial Cas9 protein. EcIAG in three genetic males was knocked out in both chromosome sets, which successfully generated sex reversal and phenotypic female characters. The results suggest that CRISPR/Cas9-mediated genome editing technology is an effective way to develop sex manipulation technology and contribute to monosex aquaculture in crustaceans

    A Novel Candidate Gene Associated With Body Weight in the Pacific White Shrimp Litopenaeus vannamei

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    Improvements of growth traits are always the focus in selective breeding programs for the Pacific white shrimp Litopenaeus vannamei (L. vannamei). Identification of growth-related genes or markers can contribute to the application of modern breeding technologies, and thus accelerate the genetic improvement of growth traits. The aim of this study was to identify the genes and molecular markers associated with the growth traits of L. vannamei. A population of 200 individuals was genotyped using 2b-RAD techniques for genome-wide linkage disequilibrium (LD) analysis and genome-wide association study (GWAS). The results showed that the LD decayed fast in the studied population, which suggest that it is feasible to fine map the growth-related genes with GWAS in L. vannamei. One gene designated as LvSRC, encoding the class C scavenger receptor (SRC), was identified as a growth-related candidate gene by GWAS. Further targeted sequencing of the candidate gene in another population of 322 shrimps revealed that several non-synonymous mutations within LvSRC were significantly associated with the body weight (P &lt; 0.01), and the most significant marker (SRC_24) located in the candidate gene could explain 13% of phenotypic variance. The current results provide not only molecular markers for genetic improvement in L. vannamei, but also new insights for understanding the growth regulation mechanism in penaeid shrimp
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