浅析类比推理在侦查中的应用

类比推理是形式逻辑中的一种推理形式 ,在人们对事物的认识中 ,使用之可以为人们提供新知识 ,认识新事物。把类比推理与侦查有效地结合起来 ,能帮助侦查人员把握案情 ,寻找不同案件间的联系 ,搜寻关键证据 ,从而探明案情 ,查出真凶。因此 ,类比推理是侦查中不可或缺的一种思维工具     

高效液相色谱法测定小鼠血清中可卡因的含量

目的 建立一种测定血清中可卡因含量的高效液相色谱方法。方法 以0.04mol/L磷酸盐缓冲液(含有0.26 mmol/L四丁基胺盐,pH3.2)-乙腈(83:17)为流动相,血清样品采用2％异戊醇正己烷-0.1 mol/L HCl液液反萃取法处理,用Kromasil C18色谱柱分析血清中可卡因的含量。紫外检测波长为235nm。结果可卡因的最小检出浓度为25ng/ml,回收率71％。结论所建方法测定血清中可卡因含量灵敏度高,简便易行。     

单核苷酸多态性及其在法医学中的应用前景

单核苷酸多态性是人类基因组中最常见、分布最广泛的DNA多态性类型。随着人类基因组计划的迅猛发展,已有越来越多的单核苷酸多态性位点被发现,使其可以广泛应用于人类遗传性和遗传相关性疾病的诊断、群体遗传学的研究、药物的开发及应用等方面,同样在法医学也具有广阔的应用前景。本文综合介绍了单核苷酸多态性的一般特性及法医学应用前景,包括其应用的可行性、存在的问题及高通量自动化的检测方法。     

Use of a commercially available hydrogel as a novel DNA surface sampling tool

A common requirement in the military, law enforcement, and forensic mission space is the need to collect trace samples from surfaces using a method that not only readily captures the sample but also retains its integrity for downstream identification and characterization. Additionally, collecting samples from three-dimensional objects (e.g., shell casings) is a challenge for which there is currently no validated standardized approach. Recently, hydrogels have been shown to have the potential for surface collection of trace bacterial spores, amino acids, and DNA. To test whether these hydrogels can serve as a viable collection medium for sampling DNA from surfaces, we carried out a series of preliminary tests examining collection efficiency and suitability of hydrogel material to recover samples of diluted, dried human DNA on a smooth polycarbonate surface. The recovery of surface DNA using a commercially available hydrogel was examined, and the efficiency compared to samples collected using a standard foam collection swab. DNA collected using the hydrogel and swab methods was then examined using quantitative polymerase chain reaction (qPCR) and short tandem repeat (STR) analysis to determine whether the collection material was compatible with these downstream processes. The hydrogel material used for this study collected the experimental DNA with comparable efficiency to standard collection swabs. In addition, qPCR and STR analyses demonstrated compatibility with the hydrogel collection and extraction process. These data suggest that hydrogels have the potential to be used as sample collection materials and deserve further characterization to elucidate their utility in collection from irregularly shaped, three-dimensional surfaces/materials.     

奶牛乳房炎四种致病菌PCR核酸免疫层析试纸条快速检测方法的建立及应用

为了开发检测导致奶牛乳房炎的无乳链球菌、金黄色葡萄球菌、大肠杆菌和停乳链球菌这四种重要致病菌的PCR核酸免疫层析试纸条方法,本研究采用柠檬酸还原法制备10 nm的胶体金溶液,选用优化的10μL 1 mol/L碳酸钾溶液调节pH和5μL异硫氰酸荧光素抗体偶联金颗粒,并使用优化的封闭液(10%BSA、0.25%PEG2000、0.05%吐温-20、0.05%Triton-X100)进行封闭,将地高辛抗体和山羊抗鼠二抗分别喷涂在检测线和质控线上,烘干并组装成试纸条,进行细菌的纯培养物和鲜牛奶加样检测。结果显示,所制备的PCR核酸免疫层析试纸条和凝胶电泳均具有较好的特异性,最低检测限要比凝胶电泳高10倍,在模拟污染牛奶样品测试中,试纸条仍然具有很好的特异性且灵敏度比凝胶电泳的高。上述结果表明,本研究建立的PCR核酸免疫层析试纸条检测方法具有良好的临床应用潜力。     

卫生纸上汗潜手印显现方法比较研究

目的通过比较实验来探寻卫生纸上汗潜手印的最佳显现方法,为实际工作提供指导性建议。方法选择市面上常见的四种卫生纸,在每种卫生纸上制作汗潜指印实验样本,分别将茚三酮溶液浸泡法与茚二酮溶液浸泡法、茚二酮溶液浸泡法与茚二酮溶液超声雾化法、茚二酮溶液超声雾化法与(对)-二甲(替)氨基肉桂醛(DMAC)显现纸冷熏法、茚二酮溶液浸泡法与红外加热显现法、茚二酮溶液超声雾化后加热显现法与室温显现法进行两两比较,分析显现效果。结果茚二酮显现的灵敏度和质量均优于其他几种方法,特别是超声雾化后室温显现,既能很好地显现手印又不影响后期的DNA检验。结论采取茚二酮超声雾化室温条件显现方法显现卫生纸上的汗潜手印具有显现效果好、设备条件要求低、操作性强的特点,在实际案件中可以借鉴应用。     

When the long road is the shortcut: a comparison between two coding methods for content-based lie-detection tools

When using a content-based lie detection tool, a decision regarding veracity is made by evaluating the presence of specific content criteria within the interviewee’s account. This evaluation can be achieved either by counting the frequency of occurrence of the criteria (frequency counts; FC) or by using a scale to rate the intensity at which they appear in the entire text (scale rates; SR). In the current study, we compared these two coding methods with respect to their accuracy in determining veracity, and their intercoder and test–retest reliabilities. Fourteen coders coded the presence of perceptual and contextual details in true and false statements, each used the FC method for one set of 30 statements and the SR method for another set of 30 statements. One month later, eight of the coders recoded 28 statements. Results showed a significant advantage for the FC method over the SR method. While the coders perceived the SR method as less time-consuming than the FC method, accuracy level as well as intercoder and test–retest reliabilities were higher for the FC than for the SR method. These findings suggest that when using a content-based lie detection tool, FC coding should be preferred over SR coding.     

牛病毒性腹泻病毒RT-PCR检测方法的建立及应用

根据GenBank中登录的牛病毒性腹泻病毒(BVDV)5′UTR基因序列,设计合成了1对特异性引物,建立了检测BVDV218bp片段的RT-PCR方法。通过对该方法的特异性、敏感性和重复性进行试验,结果显示,该方法从BVDV标准毒株OregonC24V中扩增出了218bp的特异性片段,而对猪瘟病毒、蓝舌病病毒、牛传染性鼻气管炎病毒、猪繁殖与呼吸综合征病毒、猪伪狂犬病病毒、MDBK正常细胞的扩增结果均为阴性。经对标准毒株的细胞毒进行检测,其敏感度达10-1TCID50。不同人员用该方法进行检测,结果均一致,表明其重复性好。应用该方法对70份临床疑似发病猪样品进行检测,结果检出11份阳性,阳性检出率约为15.7%。在对5份细胞培养用犊牛血清的检测中,亦检出2份阳性。表明,建立的RT-PCR方法具有特异、灵敏、高效、快速的特点,可用于BVDV的临床检测及流行病学监测。     

Effect of two types of control questions and two question formats on the outcomes of polygraph examinations

Abstract: Two major variations of polygraph “Control Question” testing, the Zone Comparison (ZoC) and the Modified General Question Test (MGQT) were evaluated. Within each, the type of control question, Exclusive or “time bar” (e.g., “Before you were 21, did you ever...”) and Nonexclusive or “no time bar”(e.g., “Did you ever….?”) was manipulated in a mock theft scenario, with 80 male and 40 female subjects randomly assigned to be either innocent or guilty. Polygraphic data collected by experienced field examiners were numerically scored by an evaluator blind to all aspects of the study. Decision accuracy was not related to the type of procedure (ZoC/MGQT) used or the subject’s sex. Accuracy was significantly related to the type of control question [χ²(2) = 11.46, p = 0.003; τc = 0.29]. Nonexclusive control questions produced greater accuracy than Exclusive control questions on both innocent and guilty subjects. These results and subjects’ self‐reports support the general “theory” on which control question (CQ) testing is based. The need for better empirical support of accepted dogma and current field practices is strongly indicated by these findings.