聚合酶链反应检测儿童急性呼吸道流感嗜血杆菌感染的研究

目的 :建立儿童急性呼吸道感染的PCR检测方法 ,并与常规方法进行比较。方法 :选择编码外膜蛋白P6基因作为靶片段设计引物 ,分别用PCR方法及常规培养法检测 78例急性呼吸道感染儿童。结果 :建立的PCR检测法可以检测 10～ 5 0个流感嗜血杆菌 ;78例急性呼吸道感染儿童中PCR方法检出 4 2株 (5 3.8% ) ,常规培养方法检出 33株 (4 2 .3% ) ,培养法检测阳性者PCR方法均为阳性。PCR方法较培养法有显著性差异。结论 :PCR方法检测呼吸道流感嗜血杆菌感染比常规方法更快速 ,更简便 ,更敏感。PCR方法检测流感嗜血杆菌有可能成为临床流感嗜血杆菌感染诊断的一种实用、理想的方法。     

基因克隆常见方法简介

本文对目前常用的一些基因克隆方法包括:抑制性差减杂交、差异显示PCR、DNA代表性差 异分析、cDNA微量列阵法(microarray)、外显子捕获法(exon capturation)、序列基因表达测(serial analysis of gene expression,SAGE)和图位克隆(mapbased cloning)等等作了简要的介绍;同时还介绍了从基因片段获得 其全长的3'RACE或5'RACE技术。可供相关研究人员参考。     

伞房属CCR基因PCR优化体系建立及多拷贝的发现和分析

对伞房属CCR基因进行扩增,对影响PCR的条件进行优化,结果筛选出引物对A-3198适宜的PCR循环条件为：94℃预变性5min;94℃变性30s,60℃退火lmin,72℃延伸2min,运行30个循环;最后72℃后延伸7min。对伞房属树种进行PCR扩增时,发现用同一引物对,一个样本可以扩增出不同长度的条带。将目的片段进行克隆测序,得到6个序列。所分析的基因片段从Exon3-Exon5,其中Exon3变异位点具有3个,Intron3无变异位点;Exon4变异位点具有7个,Intron4变异位点最多,达到276个,Exon5变异位点也只有6个。从变异位点所占百分数分析,所有外显子包括Exon3、Exon4和Exon5,变异数百分率很低,从1.67%-1.98%,说明外显子是相对保守和稳定的。Intron3最稳定,无任何差异位点。Intron4差异最大,差异百分数高达,19.99%。在Intron4有4处插入发生。第1处插入发生在第2041-2067,插入27个碱基。第2处插入发生在第2127-2289,插入163个碱基。第3处插入为PolyA,6个样本都存在PolyA。第4处为SSR序列。在外显子上未发现2个或2个以上碱基的插入/缺失。从氨基酸的变异来分析,所发生的核苷酸变异很多是无义突变,只有Exon3的2个氨基酸、Exon4的3个氨基酸,以及Exon5的2个氨基酸发生有义突变。本试验于国内外首次发现伞房属树种CCR基因具有多拷贝现象,而在桉树另外2个属桉属和杯果木属的CCR研究中未曾发现。     

A molecular biological study on identification of common septicemia bacteria using 16s–23s rRNA gene spacer regions

In the search for a rapid and reliable method for identification of bacteria in blood and cerebrospinal fluid , we developed a unified set of primers and used them under polymerase chain reaction(PCR) to amplify the spacer regions between the 16s and 23s genes in the prokaryotic rRNA genetic loci . Spacer regions within these loci showed a significant level of length and sequence polymorphism across most of the species lines. A generic pair of priming sequences was selected from highly conserved sequences in the 16s and 23s genes occurring adjacent to these polymorphic regions. This single set of primers and reaction conditions were used for the amplification of the 16s-23s spacer regions for 61 strains of standard bacteria and corresponding clinical isolates belonging to 20 genera and 27 species, including Listeria, Staphylococcus and Salmonella species, et al. When the spacer amplification products were resolved by electrophoresis, the resulting patterns could be used to distinguish most of the bacteria species within the test group, and the amplification products of the clinical isolates clustered at the standard species level. Some species presenting similar pattern were further analyzed by HinfI or AluI digestion or DNA clone and sequences analysis in order to establish the specific 16s-23s rRNA gene spacer regions map. Analysis of 42 blood specimens from septicemic neonates and 6 CSF specimens from suspected purulent meningitis patients by bacterial culture and PCR-RFLP(Restriction Fregament Length Polymorphism) showed that 15 specimens of blood culture were positive(35.7%) in the 42 septicemic neonates; 27 specimens were positive(64.2%) by PCR, and that the positive rate by PCR was significantly higher than that by blood culture(P<0.01). Among the 6 CSF specimens, one specimen found positive by blood culture was also positive by PCR, two found negative by blood culture showed positive by PCR; all three were S.epidermidis according to the DNA map. One C.neoformans found positive by blood culture showed negative by PCR. The remaining two specimens were both negative by PCR and blood culture. These results indicated that the method of detecting bacterial 16s-23s rRNA spacer regions using PCR and RFLP techniques was rapid, sensitive and specific in the detection of bacterial infections; and so, has very important application in the clinical diagnosis of sepsis in neonates.     

宽带啁啾脉冲放大理论研究

从麦克斯韦方程组出发,推导了宽带啁啾脉冲放大的理论模型方程.该方程和非线性Schr dinger方程有相同的形式,可用分步傅里叶算法对其在数值上求解.     

斑节对虾白斑综合症杆状病毒检测方法及其应用

对白斑和红体带白斑斑节对虾光镜和电镜观察，对虾白斑综合症杆状病毒（WSBV）感染外胚层和中胚层组织器官．应用WSBVPCR检测技术证实一种WSBV感染鳃、甲壳表皮、神经和肌肉，在肝胰腺、消化管（含胃）、心脏和血液中未检测到，其结果与组织学观察有出入．PCR检测WSBV最佳取材部位是对虾甲壳表皮和肌肉．PCR方法可应用于WSBV的提纯，实验用健康虾的筛选，实验感染WSBV的跟踪，以及流行病学研究．通过PCR方法和电镜观察结合证实红体病斑节对虾（不带白斑者）不是WSBV所致，修正了前人的观点．     

PipeCF： a DHT-based Collaborative Filtering recommendation system

Collaborative Filtering (CF) technique has proved to be one of the most successful techniques in recommendation systems in recent years. However, traditional centralized CF system has suffered from its limited scalability as calculation complexity increases rapidly both in time and space when the record in the user database increases. Peer-to-peer (P2P) network has attracted much attention because of its advantage of scalability as an alternative architecture for CF systems. In this paper, authors propose a decentralized CF algorithm, called PipeCF, based on distributed hash table (DHT) method which is the most popular P2P routing algorithm because of its efficiency, scalability, and robustness. Authors also propose two novel approaches: significance refinement (SR) and unanimous amplification (UA), to improve the scalability and prediction accuracy of DHT-based CF algorithm. The experimental data show that our DHT-based CF system has better prediction accuracy, efficiency and scalability than traditiona     

关于求解放大电路静态工作点的方法

以分压式偏置电路为例 ,采用戴维南定理、基尔霍夫定律和节点电位法等理论 ,讨论了求解放大电路的静态工作点     

Multiplex PCR for rapid detection of exonal deletions in patients of duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is the most common X-linked disorder in children affecting 1 in 3500 males. Since, as of now, we have no treatment for DMD, carrier detection and prenatal diagnosis is the most important preventive strategy. Multiplex PCR helps in rapid detection of hot spot exonal deletions (positive in 65% of cases) as many exons can be identified in a single run. 10 children with characterstic clinical features of DMD and chorionic villus samples of 10 antenatal patients with positive family history were studied. We identified a deletion mutation in exon 49 of the dystrophin gene in a 4 yr old boy referred with signs and symptoms suggestive of DMD using primers for exons 45, 48, 49, 43, 44, 19, 3, 8, 13 and muscle promoter, subjected to multiplex polymerase chain reaction (PCR) and agarose/Nu-Sieve gel electrophoresis. These genetic methods aid in prenatal diagnosis of DMD as well as confirmation of diagnosis in children with signs and symptoms suggestive of the disease. Work done as WHO fellow in Deptt. of Genetics, All India Institute of Medical Sciences, New Delhi.     

体育馆扩声系统的备份设计与实现——以北京五棵松凯迪拉克中心为例

针对当前体育馆的使用、扩声技术应用的特点,以北京五棵松凯迪拉克中心扩声系统安全性的设计为例,分析系统的多重主备架构设计思路及主备切换方式的实现。