SVM-based computer-aided diagnosis of the Alzheimer's disease using t-test NMSE feature selection with feature correlation weighting

This letter shows a computer-aided diagnosis (CAD) technique for the early detection of the Alzheimer's disease (AD) based on single photon emission computed tomography (SPECT) image feature selection and a statistical learning theory classifier. The challenge of the curse of dimensionality is addressed by reducing the large dimensionality of the input data and defining normalized mean squared error features over regions of interest (ROI) that are selected by a t-test feature selection with feature correlation weighting. Thus, normalized mean square error (NMSE) features of cubic blocks located in the temporo-parietal brain region yields peak accuracy values of 98.3% for almost linear kernel support vector machine (SVM) defined over the 20 most discriminative features extracted. This new method outperformed recent developed methods for early AD diagnosis.     

生物灭蚊幼控制永城市疟疾流行效果

目的研究实施生物灭蚊幼措施防治永城市疟疾暴发流行的效果。方法选择永城市2006年出现疟疾暴发和疟疾疫情较重的5个乡镇的31个行政村实施生物灭蚊幼措施,使用球形芽孢杆菌悬浮剂喷洒村内和村周水塘,剂量为8ml／m^2水面,15d喷洒一次至流行季节结束,喷洒前和喷洒后2d调查中华按蚊蚊幼密度和成蚊密度。收集疟疾报告、个案调查等资料进行统计,并与5个乡镇中未实施生物灭蚊幼措施的行政村疟疾发病情况进行比较分析。结果喷洒后2d蚊幼密度下降75．6-100％,成蚊密度下降50—100％。永城市2007年没有出现疟疾暴发点。实施生物灭蚊幼措施行政村当年共发病323例,发病率为0．48％,较上年0．98％的发病率下降51．3％,有统计学差异（X^2=118．099,P〈0．001）。与未实施生物灭蚊幼措施的行政村相比,两者2006年发病率没有统计学差异（X^2=2．818,P=-0．093）,2007年前者低于后者0．54％的发病率,有统计学差异（X^2=4．378,P=-0．036）。结论球形芽孢杆菌水面喷洒可降低中华按蚊蚊幼密度和成蚊密度,实施生物灭蚊幼措施可有效减少疟疾发病率。     

Field efficacy trial of a novel HVT-IBD vector vaccine for 1-day-old broilers

Two vaccination programmes for infectious bursal disease (IBD) were compared in broiler chickens with maternal immunity, placed on two farms. A turkey herpes virus (HVT)-IBD vector vaccine was administered by the subcutaneous route, at the hatchery, into the chicks of farm A at the age of 1 day. On farm B, an attenuated intermediate live IBD vaccine was given orally at the ages of 17 and 24 days. The vaccine uptake was monitored via serology and bursa/body weight ratio evolution, as well as PCR-based viral IBDV detection in the bursa of Fabricius at various time points. It was also verified by an experimental very virulent IBDV challenge performed at the age of 30 days in birds transferred from the farms with appropriate control groups in a laboratory. An immunity gap was observed in birds from farm B between the decay of the passive and the rise of the active immunity based upon serological data. The level of protection against challenge is not possible to establish in this farm as the reduction of the bursa/body weight ratio observed could be due to the residual pathogenicity of the vaccine strain or the challenge as well. This immunity gap was not present on farm A showing higher serological titres at the ages of 26 and 45 days via a suitable ELISA test and 93% protection against the very virulent challenge at the age of 30 days was observed. The maternal immunity interfering with the live IBDV vaccine replication had no detectable effect on the vector vaccine take.     

2008年北京奥运会病媒生物风险识别与评估方法研究

目的通过应用风险识别与评估方法,预测北京奥运会期间病媒生物危害与相关疾病发生的风险指数。及时采取应对措施,有效降低病媒生物带来的危害,避免媒介生物性传染病的发生或流行。方法通过综合分析风险性事件发生的概率和事件发生后造成的后果,对风险进行分级。首先,通过文献综述、经验分析法、头脑风暴及专家咨询法等确定风险类别,形成风险列表;然后,通过风险评价指数矩阵法综合判断风险的严重程度,并为风险排序提供统一的标准。结果北京奥运会期间存在媒介生物性传染病发生和病媒生物造成骚扰的危险。病媒生物引起的公共卫生事件（叮咬、骚扰等）及影响观瞻和环境卫生情况很可能发生,咬坏电缆、破坏电力设施的事件则比较罕见;病媒生物引起的公共卫生事件的严重程度可归纳为：咬坏电缆、破坏电力设施的事件为中等危害,叮咬、骚扰和影响观瞻、环境卫生情况危害则较小。结论通过科学地识别和评估病媒生物可能带来的危害风险、全面监测、综合防制、科学用药、组建应急队伍和推广先进技术等措施,确保实现北京奥运会无重大病媒生物危害事件发生的控制目标。     

密云地区莱姆病螺旋体宿主动物和传播媒介感染状况调查

目的了解密云地区莱姆病宿主动物和传播媒介的感染情况,以及宿主动物的分布情况和传播媒介蜱的季节消长规律,为密云地区莱姆病的防制提供科学依据。方法采用布旗法捕蜱,用倒置显微镜观察蜱的形态,对蜱进行鉴定。采用夹夜法捕鼠;用BSKII培养基对蜱和鼠标本进行病原分离。采用巢式聚合酶链反应（PCR）对蜱和鼠进行病原学检测。羊血清莱姆病抗体检测采用间接免疫荧光抗体法。结果密云地区捕获的蜱均为长角血蜱,其消长曲线具有明显的季节性,巢式PCR检测蜱带菌率为10．16％;黑线姬鼠和北社鼠是该地区优势鼠种,巢式PCR检测鼠带菌率为4．26％;当地放养山羊血清学检测阳性率为12．00％。结论在蜱和鼠中均检测到莱姆病螺旋体的特异片段,表明密云地区可能为莱姆病自然疫源地。     

Infection of adult Aedes aegypti and Ae. albopictus mosquitoes with the entomopathogenic fungus Metarhizium anisopliae

This study describes a laboratory investigation on the use of the insect-pathogenic fungus Metarhizium anisopliae against adult Aedes aegypti and Ae. albopictus mosquitoes. At a dosage of 1.6 x 10(10)conidia/m(2), applied on material that served as a mosquito resting site, an average of 87.1+/-2.65% of Ae. aegypti and 89.3+/-2.2% of Ae. albopictus became infected with the fungus. The life span of fungus-contaminated mosquitoes of both species was significantly reduced compared to uninfected mosquitoes. LT(50)-values of fungus-contaminated mosquitoes ranged between 3.1+/-0.2 days (male Ae. aegypti) and 4.1+/-0.3 days (female Ae. aegypti). LT(50)-values of uncontaminated mosquitoes ranged from 17.7+/-0.4 days (female Ae. albopictus) to 19.7+/-0.6 days (male Ae. albopictus). These results indicate that both mosquito species are highly susceptible to infection with this entomopathogen. Requirements for developing and incorporating this biological control method into current strategies to control major diseases vectored by these species, such as dengue fever, are discussed.     

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。     

“模拟钉螺”制作材料的研究

目的利用对日本血吸虫毛蚴有趋向作用的物质制作＂模拟钉螺＂吸引毛蚴。方法选用明胶、琼脂做载体材料,加入Fe3＋制成＂模拟钉螺＂。采用改良的Roberts比较法观察＂模拟钉螺＂及螺狮处理过的水（SCW）对毛蚴的趋向性。结果 Fe3＋浓度分别为0.1、0.5 mol/L,明胶含量分别为9%和10%的凝胶颗粒,以及Fe3＋浓度为0.5 mol/L、明胶含量为9%,琼脂含量为1%或2%的混合凝胶颗粒可作为＂模拟钉螺＂载体,所制作的＂模拟钉螺＂对毛蚴的趋向性较SCW更强。结论按一定配比制成的含Fe3＋的明胶以及明胶和琼脂的混合物均可作为＂模拟钉螺＂载体的制作材料。     

云南省潞西市蚊虫调查及乙型脑炎病毒分离

1984年7月,在潞西市农村畜圈及野外竹林捕获成年雌性蚊虫4属12种2690只。三带喙库蚊是农村畜圈的优势蚊种.伪白蚊伊蚊是野外竹林的优势种。从三带喙库蚊中分离到1株乙型脑炎病毒,表明该蚊是当地乙型脑炎病毒的主要传播媒介。     

Extension of indoor residual spraying for malaria control into high transmission settings in Africa

Contrary to previous consensus, a recent WHO statement recommends a more dominant role for indoor residual spraying (IRS) in malaria control in high transmission settings of sub-Saharan Africa and re-emphasises the role of DDT. We review the issues related to this change in recommendation. In high transmission settings, IRS must be implemented indefinitely and at high quality to achieve control. As current infrastructure limitations and unpredictable funding make this unlikely, each country must carefully consider the role of IRS. There remains a need to support ongoing insecticide-treated net scale-up. Insecticide choice is hampered by the lack of economic costing data.