基于遗传算法与支持向量机的基因微阵列分析

背景：微阵列数据的特点是样本含量小,而变量数(基因)多达上万个。此时,传统的统计方法往往因为高维而失效了。遗传算法和支持向量机是近年来发展迅速的机器学习算法,具有很好的分类效果与降维优势。目的：提出将遗传算法与支持向量机结合起来对样本进行分类,并与直接采用支持向量机、筛选差异表达基因后采用支持向量机的结果进行比较。方法：采用Bioconductor提供的数据集golub,它是白血病微阵列芯片实验所得的基因表达数据集,对全部基因采用支持向量机进行分类。采用SAM软件对芯片数据的显著性分析确定不同的差异表达基因并估计错误发现率FDR,以筛选出的76个差异表达基因作为特征基因子集,再采用支持向量机进行分类。将筛选出的76个差异表达基因作为初始的特征基因集合,采用遗传算法－支持向量机再次进行特征基因选择,提高分类准确度,并与全部基因直接采用支持向量机、筛选差异表达基因后采用支持向量机的结果进行比较。同时也对特征基因在代谢通路上的分布和功能作了一定的研究。结果与结论：通过遗传算法降维可以提高支持向量机的分类准确率,特别是剔除了数据中的大量无关基因和噪声,使得经过特征选择后分类准确率提高。结果显示遗传算法与支持向量机结合方法对分类更加有效。此外,通路分析结果显示特征基因的主要功能体现在信号传导和氨基酸代谢上。     

基于中国可视人数据集的图像矢量化研究

目的设计并应用将中国可视人数据集中的图片转换为矢量图的算法。方法设计一个算法,并按照此算法设计一个特定的程序,此程序的输出文件格式为ScalableVectorGraphicsSVG,并在轮廓和色彩上比较原来位图和转换后的图形。结果该算法可以对分割后图像进行理想效果的转化,对色彩梯度大的图像,该算法的复杂度会增加。结论该图像格式可以作为一个交换数据存在,对分割后图像有理想的转化效果。在现阶段各种可视化程序的分割机制不同有各种不同的中间文件格式,实施SVG格式标准有助于规范异构可视化平台的数据统一性。     

髓样相关蛋白14真核表达载体的构建及其细胞内定位研究

目的:构建小鼠髓样相关蛋白14(MRP14)的真核表达载体,观察其在NIH3T3细胞中的表达定位情况。方法:提取BALB/c小鼠肝脏组织的总RNA,通过逆转录-聚合酶链反应(RT-PCR)扩增得到MRP14编码序列。然后将该编码序列克隆到带有血凝素(HA)标记的载体pcDNA3-HA上,随后转染NIH3T3细胞,在荧光显微镜下观察结果。结果:重组质粒经聚合酶链反应(PCR)、酶切和测序鉴定证明构建正确。转染实验发现,该质粒能够在NIH3T3细胞中表达,表达产物主要定位在细胞质中。结论:成功构建带HA标签的MRP14真核表达载体。该载体能在哺乳动物细胞中有效表达并正确定位,为下一步深入研究MRP14作用细胞的信号通路提供了一个重要工具。     

江苏省2008-2009年疟疾媒介按蚊监测结果分析

目的了解江苏省疟区中华按蚊种群数量、密度的发展变化趋势和对杀虫剂的敏感性。方法在疟疾流行季节,采用人饵诱捕法、猪舍捕蚊法和WHO推荐的接触筒强迫接触法,观察接触10、15、20、30、40、50、60min时蚊虫对杀虫剂的击倒率和24h时死亡率。结果 2008年6月下旬至10月上旬半通宵帐内人饵共捕获按蚊322只,经鉴定均为中华按蚊,平均叮人率为1.61只/(人.h);猪舍内共捕获按蚊886只,经鉴定均为中华按蚊,平均密度为147.66只/人工小时;中华按蚊对溴氰菊酯已达到抗性(R)水平;对氟氯氰菊酯为初步抗性(M)水平。2009年6月下旬至10月上旬半通宵帐内人饵共捕获按蚊349只,经鉴定均为中华按蚊,平均叮人率为1.25只/(人.h);猪舍内共捕获按蚊652只,经鉴定也均为中华按蚊,平均密度为108.67只/人工小时。中华按蚊对溴氰菊酯抗性为R级水平;对马拉硫磷抗性也为R级水平。结论江苏省部分疟区中华按蚊已对溴氰菊酯产生抗性,对氟氯氰菊酯已产生初步抗性。今后,在采用杀虫剂浸泡蚊帐或室内滞留喷洒等方法对暴发点或疫情不稳定地区进行处理时,应选择适合的杀虫剂,以达到防制效果;同时为控制疟疾发病,应加强对当地居民的健康教育,提高防蚊意识,减少人蚊接触机会。     

上海市嘉定区病媒生物监测结果分析

目的了解嘉定区病媒生物的种类及其季节消长规律,为预防和控制病媒生物传播疾病的发生和流行提供依据。方法按照《全国病媒生物监测方案(试行)》设置监测点,分别以夹日法、笼诱法、灯诱法和粘捕法调查鼠、蝇、蚊、蜚蠊的种类和密度。结果调查发现嘉定区鼠类1科2属3种,小家鼠为优势鼠种(占69.23%),其次是褐家鼠(占21.15%),鼠密度9月最高;蝇类3科4属4种,家蝇为优势种,占捕获总数的68.49%,7月为全年密度最高峰;蚊虫有2科2属3种,分别为淡色库蚊、三带喙库蚊和中华按蚊,淡色库蚊为优势蚊种(占73.83%),其次为三带喙库蚊(占12.58%)和中华按蚊(占13.59%),8月为全年密度最高峰;蜚蠊有2科2属2种,德国小蠊为优势种(占89.29%),7月为全年密度最高峰。结论嘉定区鼠、蝇、蚊、蜚蠊优势种分别为小家鼠、家蝇、淡色库蚊和德国小蠊,密度高峰鼠类为9月,蚊类为8月,其它病媒生物均为7月。     

Do plastics serve as a possible vector for the spread of antibiotic resistance? First insights from bacteria associated to a polystyrene piece from King George Island (Antarctica)

The retrieval of a polystyrene macro-plastic piece stranded on the shores in King George Island (South Shetlands, Antarctica) gave the opportunity to explore the associated bacterial flora. A total of 27 bacterial isolates were identified by molecular 16s rRNA gene sequencing and 7 strains were selected and screened for their ability to produce biofilm and antibiotic susceptibility profiles. All the bacterial isolates were able to produce biofilm. The Kirby-Bauer disk diffusion susceptibility test to 34 antibiotics showed multiple antibiotic resistances against the molecules cefuroxime and cefazolin (belonging to cephalosporins), cinoxacin (belonging to quinolones) and ampicillin, amoxicillin + clavulanic acid, carbenicillin and mezlocillin (belonging to beta-lactams). The obtained results suggest that plastics can serve as vectors for the spread of multiple resistances to antibiotics across Antarctic marine environments and underline the relevance of future studies on this topic.     

中国2013年登革热流行病学分析

目的根据2013年全国登革热监测数据,分析我国登革热流行病学特征与趋势,探讨相应防治对策及建议。方法利用2013年"传染病报告信息管理系统"和5省监测点上报数据,进行回顾性描述分析。结果 2013年全国26个省(自治区、直辖市)共报告登革热病例4 663例,其中,本地感染病例4 293例,无死亡病例。报告发病数居前5位的省份依次为广东(2 894例)、云南(1 538例)、浙江(37例)、河南(36例)和福建(33例)。部分监测点高发季节布雷图指数显著高于预警值,提示传播风险较大。结论我国已存在登革热输入病例增加、多点本地暴发和重点地区蚊媒密度较高等诸多风险因素,发生登革热本地暴发的风险不断增加。加强病例与蚊媒监测,促进社会动员与部门合作,在疫情早期及时采取综合防控措施,是防止疫情蔓延的重要措施。     

河南省淮滨县实施全球基金疟疾项目效果的评价

[目的]评价河南省淮滨县2003～2005年实施全球基金疟疾项目期间的疟疾疫情、防治措施及防治效果。[方法]收集淮滨县2003～2005年疟疾流行、防治措施、防治效果及媒介监测资料,分析流行情况,评价防治措施及效果。[结果]2003～2005年淮滨县共报告疟疾病例1765例,平均年发病率为8.93/万。2004年和2005年疟疾发病分别比上年下降53.58%和72.04%。建立发热病人镜检站18个,血检发热病人39070人,发现650例阳性病人。捕获中华按蚊4744只,未发现嗜人按蚊,疟疾暴发发点氟氯氰菊酯药物浸泡蚊帐340顶。氯、伯喹治疗现症病人1765人,休止期服药7571人,流行季节预防服药2471人。培训专业技术116人次,疟防宣传6259份,督导检查108次。居民和中小学生疟防知识知晓率由2003年的14.36%和9.36%提高到2004年的54.21%和47.36%。2005年144例疟疾病人平均确诊时间(2.82±2.89d)显著低于河南省的平均确诊时间(6.64±10.49d)(单样本t检验,t=-15.844,P=0.000)。[结论]在全球基金疟疾项目的支持下,河南省淮滨县疟防工作成绩显著,以项目管理促进疟防的方式值得推广。     

Common Carotid Artery Flow Measured by 3-D Ultrasonic Vector Flow Imaging and Validated with Magnetic Resonance Imaging

Ultrasound (US) examination of the common carotid artery was compared with a through-plane magnetic resonance imaging (MRI) sequence to validate a recently proposed technique for 3-D US vector flow imaging. Data from the first volunteer examined were used as the training set, before volume flow and peak velocities were calculated for the remaining eight volunteers. Peak systolic velocities (PSVs) and volume flow obtained with 3-D US were, on average, 34% higher and 24% lower than those obtained with MRI, respectively. A high correlation was observed for PSV (r = 0.79), whereas a lower correlation was observed for volume flow (r = 0.43). The overall standard deviations were ±5.7% and ±5.7% for volume flow and PSV with 3-D US, compared with ±2.7% and ±3.2% for MRI. Finally, the data were re-processed with a change in the parameter settings for the echo-canceling filter to investigate its influence on overall performance. PSV was less affected by the re-processing, whereas the difference in volume flow between 3-D vector flow imaging and MRI was reduced to ?9%, and with an improved overall standard deviation of ±4.7%. The results illustrate the feasibility of using 3-D US for precise and angle-independent volume flow and PSV estimation in vivo.     

Immunization of bighorn sheep against Mannheimia haemolytica with a bovine herpesvirus 1-vectored vaccine

Mannheimia haemolytica is an important pathogen of pneumonia in bighorn sheep (BHS), consistently causing 100% mortality under experimental conditions. Leukotoxin is the critical virulence factor of M. haemolytica. In a ‘proof of concept’ study, a vaccine containing leukotoxin and surface antigens of M. haemolytica induced 100% protection in BHS, but required multiple booster doses. Vaccination of wildlife is difficult. BHS, however, can be vaccinated at the time of transplantation, but administration of booster doses is impossible. A vaccine that does not require booster doses, therefore, is ideal for vaccination of BHS. Herpesviruses are ideal vectors for development of such a vaccine because of their ability to undergo latency with subsequent reactivation which obviates the need for booster administration. The objective of this study was to evaluate the potential of bovine herpesvirus 1 (BHV-1) as a vector encoding M. haemolytica immunogens. As the first step towards this goal, the permissiveness of BHS for BHV-1 infection was determined. BHS inoculated with wild-type BHV-1 shed the virus following infection. The lytic phase of infection was superseded by latency, and treatment of latently-infected BHS with dexamethasone reactivated the virus. A recombinant BHV-1-vectored vaccine encoding a leukotoxin-neutralizing epitope and an immuno-dominant epitope of the outer membrane protein PlpE was developed by replacing the viral glycoprotein C gene with a leukotoxin-plpE chimeric gene. Four of six BHS vaccinated with the recombinant virus developed significant leukotoxin-neutralizing antibodies at day 21 post-vaccination, while two of six BHS developed significant surface antigen antibodies at day 17 post-vaccination. These antibodies, however, were inadequate for protection of BHS against M. haemolytica challenge. These data indicate that BHV-1 is a suitable vector for immunization of BHS, but additional experimentation with the chimeric insert is necessary for development of a more efficacious vaccine.