Application of Random Match Probability Calculations to Mixed STR Profiles

Mixed DNA profiles are being encountered more frequently as laboratories analyze increasing amounts of touch evidence. If it is determined that an individual could be a possible contributor to the mixture, it is necessary to perform a statistical analysis to allow an assignment of weight to the evidence. Currently, the combined probability of inclusion (CPI) and the likelihood ratio (LR) are the most commonly used methods to perform the statistical analysis. A third method, random match probability (RMP), is available. This article compares the advantages and disadvantages of the CPI and LR methods to the RMP method. We demonstrate that although the LR method is still considered the most powerful of the binary methods, the RMP and LR methods make similar use of the observed data such as peak height, assumed number of contributors, and known contributors where the CPI calculation tends to waste information and be less informative.     

HS/GC/ECD分析生物检材样品中的氰化物

目的 建立生物样品中氰化物的衍生化定性定量分析方法。方法 用氯胺T衍生化,HS/GC/ECD分析衍生物CICN。结果 在1ml血中,添加0.2μg氰化钾,回收率为84.6％,RSD为6.39％;在1g肝中添加0.5μg氰化钾,回收率为67.3％,RSD为5.05％;血中检出限为5ng/ml。结论 所建方法能定性定量分析生物样品中的氰化物。     

生物识别技术在警务工作中的应用

为了维护社会治安的正常秩序,警务工作要建立有效社会控制机制,应用生物识别技术防范及处置影响社会稳定的案件和事件。生物识别技术发展迅速,在警务工作应用广泛。     

液相色谱-串联质谱法检测生物样品中百草枯及其代谢物

目的建立生物样品中百草枯(paraquat,PQ)及其2种主要代谢物monoquat,paraquatmonopyridone(MP)的液相色谱-串联质谱(LC-MS/MS)检测方法,应用于百草枯中毒案件的法医学鉴定。方法生物样品经乙腈或甲醇沉淀蛋白,使用Agilent HILIC Plus(4.6×100mm,3.5μm)色谱柱,以0.1%甲酸水溶液～0.1%甲酸乙腈溶液(v/v)为流动相进行洗脱,在多反应监测模式下检测。结果百草枯及其代谢物在1～1000ng/mL内线性关系良好,相关系数(r)≥0.9996,最低检出限为0.34～6.00ng/mL,检测准确度为91.25%～113.44%,日内及日间精密度分别为1.51%～3.99%和1.92%～4.93%。结论本文建立的LC-MS/MS法具有灵敏度高、特异性好的特点,可应用于百草枯中毒相关案件的法医学鉴定。     

生物材料中二氯苯醚菊酯的反相高效液相色谱分析方法研究

目的为了解决二氯苯醚菊酯中毒检验的问题及进一步开展研究工作，建立多种生物材料中二氯苯醚菊酯高效液相色谱分析方法。方法选用shim—pack，CLC—ODS（5μm）作色谱柱，甲醇：水：冰醋酸（90：10：1）为流动相，检测波长为274mm。用空白添加试验系统地考察提取，净化方法及高效液相色谱分析条件。用日本大耳兔进行急性染毒，取材对所建方法进行验证。结果采用所建方法，空白组织添加回收率在0．2～20μg／g的范围内均大于85％；工作曲线线性良好（r＝0．9998）；以信噪比≥3计，最低检测限为10ng／g组织；方法重现性良好（CV＜4．5％，n=3）；染毒兔各组织中的内源性杂质均不干扰二氯苯醚菊酯的检测。结论所建方法适用于检测多种生物材料中的二氯苯醚菊酯，方法灵敏、准确，可望用于二氯苯醚菊酯的中毒检验、代谢动力学及分析毒理学的研究。     

Detection of saliva traces using test strips

The test strip Rapignost-Amylase (Behring) for the rapid determination of alpha-amylase in the urine is also suitable for the determination of salivary amylase in stains stored up to 6 weeks at room temperature. The stains are extracted with physiological saline (extraction time 30 min), then the application zone of the strip is wetted with the extract. Positive amylase-reaction is recognised as a reddish-violet colouration of the reaction zone. Biological stains with low amylase concentrations (urine semen, vaginal secretion, mucus) react amylase negative. The method is uncomplicated and can be completed within 30 min. The test strips are easily available and stable during storage. Therefore the determination of saliva with test strips should be preferred to the clinical methods if the storage times of the stain are not longer than 4-6 weeks. It is a suitable procedure to determine salivary stains for use in forensic biology.     

混合斑中精子细胞分离及其DNA制备方法

目的尝试建立一种检测混合斑中精子细胞的方法。方法使用显微操作法捕获精子细胞,全基因组扩增(多重置换扩增)精子细胞DNA。结果对10管精斑检材的全基因组扩增,获得了高产、保真的产物。使用50μL体系对20个精子细胞直接进行全基因组扩增,省去了对起始模板的纯化过程,DNA扩增倍数达30000倍以上,片段长度大多在15 kb以上,其STRs复合扩增分型结果有可参照性。结论显微操作法可以有效捕获精子细胞,排除干扰,多重置换扩增可以提供足够量的产物用于法医DNA分析,该方法具有可行性。     

Simultaneous detection and image capture of biological evidence using a combined 360° camera system with single wavelength laser illumination

Forensic investigators frequently utilise light sources to detect and presumptively identify biological evidence. The instrumentation typically deploys single or multiple wavelength exposures at various intensities, which interact with constituents of biological material, initiating fluorescence or improving contrast between the material and substrate. Documentation using sketches and/or photographic approaches follows detection, which are essential for scene reconstruction. Recent research has demonstrated the simultaneous detection and capture of biological evidence using a 360° camera system combined with an alternate light source exhibiting broad wavelength ranges of light. Single wavelength light sources reportedly offer enhanced sensitivity, due to the increased light intensity and narrower bandwidth of light, although their combined use with a 360° camera system has not yet been explored.Samples of human blood, semen, saliva, and latent fingermarks were deposited on to a variety of substrates. A 360° camera system combined with a laser light source was used to detect and capture the samples. Ten participants were asked to detect the samples on images of the substrates without ground truth knowledge. It was possible to detect and capture biological evidence, although success varied according to substrate colour and light intensity. Advantageously, presumptive screening for biological fluids and the simultaneous location and visualisation of such evidence as part of a 360° panorama of the scene for contextual purposes was permitted. There was no fluorescent response from the fingermarks, although the oblique lighting effects appeared sufficient to aid mark detection in some circumstances. The use of single wavelength illumination clearly facilitates identification of a range of forensically important material. When coupled with a 360-degree camera, this allows for simultaneous identification and recording of such evidence in the context of the whole environment.     

Determination of triptolide and wilforlide A in biological samples by LC-MS/MSCSCD

Objective: To determinate triptolide and wilforlide A in biological samples by liquid chromatography-tandem mass spectrometry (LC-MS/MS) method and to verify the method. Methods: After 0.4 mL blood, urine or 0.4 g hepatic tissues with internal standard were extracted by ethyl acetate, they were separated on a Allure PFP Propyl (100 mm × 2.1 mm, 5 μm) with a mobile phase of methanol-20 mmol/L ammonium acetate using gradient elution. For mass spectrometric detection, electrospray ionization (ESP) in positive mode was elected and the data was collected using multiple-reaction monitoring (MRM). Results: The linearity was good (r>0.9950) and the limit of detection was 2 ng/mL or 2 ng/g for triptolide and wilforlide A. The recovery was 61.08%-102.98%. The intra-day and inter-day precision was less than 12.58% for each biological sample, and the accuracy was 90.61%-105.80%. Conclusion: This method is simple, convenient and good selective, and could be applied to analysis of triptolide and wilforlide A in different biological samples. And the method may provide technical support for forensic medicine identification, clinical diagnosis and treatment of tripterygium wilfordii Hook. f. poisoning. © 2015 by the Editorial Department of Journal of Forensic Medicine.