产志贺毒素大肠杆菌O26多重双启动寡核苷酸引物-PCR检测方法的建立

为建立一种三重DPO-PCR方法用于食品样品中的产志贺毒素大肠杆菌O26的检测。以志贺毒素stx1和stx2、O抗原基因wzx O26特异性和实际检测效果,设计引物,构建三重DPO-PCR反应体系,进行特异性、灵敏度、模拟样品验证和实际样品验证。结果表明,三对DPO引物对退火温度不敏感,在49~69℃之间均能发生扩增,且引物之间干扰较小,具有较高的特异性,除目的基因外非目标细菌均无扩增条带出现,纯菌灵敏度检测表明,三重DPO-PCR方法对O26的最低检测限为3.8×10^3 cfu/g。在模拟样品和实际样品中具有良好的检测效果。本研究基于DPO引物构建的三重DPO-PCR方法具有效率高,特异性强,不受退火温度限制等优点,可用于食品样品中产志贺毒素大肠杆菌O26的快速准确检测提供一种高效的辅助检测方法。     

Termination Criteria for DPO Transformations with Injective Matches

Reasoning about graph and model transformation systems is an important means to underpin model-driven software engineering, such as Model-Driven Architecture (MDA) and Model Integrated Computing (MIC). Termination criteria for graph and model transformation systems have become a focused area recently. This paper provides termination criteria for graph and model transformation systems with injective matches and finite input structure. It proposes a treatment for infinite sequences of rule applications, and takes attribute conditions, negative application conditions, and type constraints into account. The results are illustrated on case studies excerpted from real-world transformations, which show the termination properties of the frequently used "transitive closure" and "leaf collector" transformation idioms. An intuitive comparison with other approaches is also given.     

2,5-二苦基-1,3,4-噁二唑的制备研究

研究了２，５－二苦基－１，３，４－口恶二唑（ＤＰＯ）的制备技术，探讨了ＤＰＯ的４步合成方法、关键技术和工艺条件，对４步产物进行了结构认定，改进了第３步产物——双（２，４，６－三硝基苯甲酰）肼（ＢＴＮＢＨ）的合成，提高了产率。     

应用DPO技术检测食源性致病菌的多重PCR的研究

DPO是经特殊设计的特异性引物,本研究根据单增李斯特菌的prfA gene、O157的rfb Egene和副溶血弧菌的tlgene和志贺氏菌的ipaH gene设计四对DPO引物,采用多重PCR的方法,建立了检测单增李斯特菌、大肠杆菌O157:H7、副溶血弧菌和志贺氏菌的快速检测体系。实验结果表明:该体系特异性强,操作简单,为食源性致病菌的检测提供了新型的有效手段。     

Simultaneous detection of Vibrio cholerae,Vibrio alginolyticus,Vibrio parahaemolyticus and Vibrio vulnificus in seafood using dual priming oligonucleotide (DPO) system-based multiplex PCR assay

In this study, a rapid and reliable multiplex PCR assay for simultaneous detection of Vibrio cholerae, Vibrio parahaemolyticus, Vibrio vulnificus and Vibrio alginolyticus in seafood was developed using the dual priming oligonucleotide (DPO) system. Species-specific DPO primers were designed targeting the mdh, vvhA, colH and toxR genes for the discrimination of V. cholerae, V. vulnificus, V. alginolyticus and V. parahaemolyticus, respectively. Compared to conventional PCR assay, the DPO system-based multiplex PCR assay allowed a wider annealing temperature at 48 °C–68 °C to effectively amplify target genes followed an analytical detection limit of <1.5 × 10² CFU/mL (or g) for each Vibrio species in pure cultures or artificially contaminated food matrix. A total of 396 bacterial strains including 209 targets and 187 other bacterial strains were used to test the specificity of the DPO system-based multiplex PCR assay, and results showed that specific PCR product was only observed in target bacterial strains without nonspecific priming. Practical application of the assay indicated that target Vibrio species in seafood, clinical samples and foodborne outbreaks can be accurately detected. This DPO system-based multiplex PCR assay developed in this study would be a powerful tool for the rapid and reliable detection of the target Vibrio species.     

负载型MoO3/SiO2催化剂催化酯交换合成草酸二苯酯的反应性能

 以钼酸铵、二氧化硅为原料，采用浸渍法制备了负载型的MoO₃/SiO₂催化剂，通过草酸二乙酯与苯酚酯交换反应合成草酸二苯酯。分别考察了不同载体，不同反应温度，不同反应时间，不同原料配比，不同负载量等条件对反应性能的影响，采用XRD、XPS表征技术研究了催化剂表面活性组分的分散状态对草酸二乙酯和苯酚酯交换反应的影响。其中，MoO3负载量6%的MoO3/SiO2催化剂催化性能最好，DEO转化率54.9%，DPO收率13.7%，EPO收率41.2%，目的产物DPO和EPO选择性的总选择性为100%。     

利用DPO7104示波器资源构建测试系统

本文在介绍DPO7104示波器性能、特点和将操作系统中的英文字体改为中文字体的基础上,描述了在自动测量或自动测试系统开发过程中,如何利用其本身带的PCI—GPIB接口卡和OpenChoice仪器管理软件,管理接入DPO7104示波器的各种接口的资源及在LabVIEW8．5开发环境下利用仪器资源名,通过GPIB接口设计脉）中频率测量程序的方法,经应用证明该方法简单实用,避免了资源浪费,对开发设计测试软件者具有参考借鉴价值。     

新型耐热钝感传爆药2,5-二苦基-1,3,4-噁二唑性能研究

测试了2,5-二苦基-1,3,4-噁二唑(DPO)的基本性能,并与六硝基菧(HNS)进行了对比,研究了DPO的安全性和慢速烤燃性能,探索了DPO在冲击片雷管和钝感传爆药中的应用.结果表明:DPO是一种热安定性良好且冲击波感度相对敏感的炸药,基本理化和热性能与HNS相当.DPO能够通过传爆药安全性鉴定试验,可以作为许用传...     

最小外型全功能波形监测仪满足视频测试

一直以来,泰克(Tektronix)公司在不断地推动视频产业链的技术创新和演进。2010年推出了WVR8300/8200,支持立体3D视频测量。WFM/WVR6xxx/7xxx系列产品新增了音频响度测量。     

高性能开放式示波器加快嵌入式调试

在目前中档示波器(350 MHz～2GHz)的市场上,解决方案还存在着一些不足,特别是在探测、发现、捕获以及搜索和分析的5个调试阶段,客户有更高的期望. 根据客户的需求,泰克(Tektronix)公司日前推出了全新的MSO/DPO5000系列示波器,升级的MSO/DP04000B系列以及新高带宽无源探头为加快嵌入式设计人员调试的每个阶段,提供更高性能和更多分析功能.