5种免提取试剂盒检验滤纸血痕结果的比较

目的探讨5种免提取试剂盒对滤纸血痕样本检验的效果。方法陈旧滤纸血痕(存放时间12～14个月)及新鲜滤纸血痕(存放时间小于1个月)各920份,分别随机分为5组。应用AGCU 17+1、Goldeneye 20A、Powerplex16HS、Identifiler Plus、Identifiler Direct 5种免提取试剂盒进行检验,对比各组检验结果。结果陈旧滤纸血痕5种试剂盒的检验成功率为98.91%～100%,各组间无差异(P>0.05);新鲜滤纸血痕,Identifiler Plus和Identifiler Direct试剂盒检验成功率高于AGCU17+1、Goldeneye 20A及Powerplex 16HS试剂盒(P<0.01);将样本做陈旧化处理后再用成功率较低的3种试剂盒进行检验,成功率分别升至100%、99.46%、99.46%;Identifiler Plus试剂盒扩增循环27次效果优于28次。结论本文5种试剂盒均可用于滤纸血痕的直接扩增检验,但使用AGCU17+1、Goldeneye 20A及Powerplex 16HS试剂盒需将新鲜血痕做陈旧化处理;Identifiler Plus试剂盒需将循环次数降为27次。     

伪装签名检验初探

伪装签名是一种签名造假手段,其目的是通过否认签名是自己所写,非法占有他人财物或逃避责任。伪装签名笔迹貌似正常,但受不同伪装手段的影响,笔迹会发生各种变化,因而检验难度较大。检验伪装签名时,鉴定人要解放思想,客观看待笔迹发生的变化,选用正确的检验方法,客观全面地选择笔迹特征,适时补充笔迹样本,条件具备时还应充分利用案情。     

Can a machine be used to replicate the biomechanics of human stabbing performance?

A human performance trial was conducted where the stabbing actions of 40 participants were investigated. A range of factors were assessed such as the action used when the blade shape and familiarity of the knife changed. A qualitative evaluation of these factors was presented in an earlier paper to precede the analysis of quantitative kinematic data in this paper. The data from participants was then compared to that obtained from a stabbing machine.A motion analysis system was used to measure parameters such as the joint angular displacement and absolute linear velocity at impact. Motion data was collected using a 12-camera Vicon MX motion analysis system. Results indicated that the mean absolute linear velocity of overarm stabbing actions was consistently higher than the underarm actions.Forensic textile damage examinations often involve testing of edged weapons by manually performing stabbing actions. An underlying fundamental limitation of manual simulation experiments is the natural variation inherent in human performance. Sufficient control measures can be implemented to successfully use manual simulation experiments in forensic testing and therefore this is the accepted practice. However, performance can be improved using a stabbing machine. A custom-built instrumental stabbing device has been shown to operate within the same parameters of the human participants and is therefore suitable for use in casework.     

PDU结构分析在手机短信检验鉴定中的应用

PDU模式下的短信息编码方式,被GSM手机广泛运用。在实际检验鉴定工作中,涉案手机检验量大幅增加,并且手机检验分析系统无法解析镜像文件的情况时有发生,检验人员只有对PDU有足够的了解,才能对手机取证驾轻就熟。通过对PDU模式结构的实例分析,手工成功恢复出手机短信息,这种分析的方法和经验可以应用于所有GSM手机的短信息取证。     

OpenLV: Empowering investigators and first-responders in the digital forensics process

The continuing decline in the cost-per-megabyte of hard disk storage has inevitably led to a ballooning volume of data that needs to be reviewed in digital investigations. The result: case backlogs that commonly stretch for months at forensic labs, and per-case processing that occupies days or weeks of analytical effort. Yet speed is critical in situations where delay may render the evidence useless or endanger personal safety, such as when a suspect may flee, a victim is at risk, criminal tactics or control infrastructure may change, etc. In these and other cases, investigators need tools to enable quick triage of computer evidence in order to answer urgent questions, maintain the pace of an investigation and assess the likelihood of acquiring pertinent information from the device.This paper details the design and application of a tool, OpenLV, that not only meets the needs for speedy initial triage, but also can facilitate the review of digital evidence at later stages of investigation. With OpenLV, an investigator can quickly and safely interact with collected evidence, much as if they had sat down at the computer at the time the evidence was collected. Since OpenLV works without modifying the evidence, its use in triage does not preclude subsequent, in-depth forensic analysis. Unlike many popular forensics tools, OpenLV requires little training and facilitates a unprecedented level of interaction with the evidence.     

Dating of Seals Produced with Stamp‐Pad Ink Using Gas Chromatography Method

Seals are often placed on important documents, and determining the date when a seal was affixed can be important to assess the authenticity of a document. In this study, thirty‐seven different brands of stamp‐pad inks and three different types of paper were used to make diachronic samples of the seals. The volatile components of stamp‐pad ink were determined, and the stamp‐pad ink was classified by gas chromatography with a flame ionization detector. Calibration curves were created to show the relationship between the content of volatile stamp‐pad ink components and the age of stamp‐pad ink entries stored under natural aging, UV‐induced aging, and heating aging conditions. The experimental results showed that GC was useful in the analysis of stamp‐pad ink and applicable for determining the relative age of stamp‐pad ink entries in some cases where the seal was placed on the document within 3 months.     

A Calibration Test for Latent Fingerprint Development on Thermal Paper

A calibration test is described for monitoring the operation of equipment used to develop latent fingerprints on thermal paper by the application of either controlled or uncontrolled heat. A working solution of a water/glycerol emulsion and butylene glycol is applied to thermal paper by means of either a vinyl stamp and pad, or a marker pen. Varying the amount of butylene glycol enables the thermal paper to change color at different temperatures between approximately 40 and 60°C, which is below the normal color change temperature of the paper. The described test may be used to verify the correct operation, at different temperatures, of a controlled heat source during and after fingerprint development (such as the Hot Print System) or to monitor the paper temperature with an uncontrolled heat source (such as a warm air blower), thereby avoiding unintentional coloring of the entire paper surface.     

显微镜在毛发物证检验中的应用

显微镜作为较普及的检验仪器,应用广泛。介绍了普通光学显微镜、扫描电子显微镜、红外显微镜、偏光显微镜、相差显微镜、暗视野显微镜在毛发物证结构或成分检验中的应用。     

胶印同版印刷品的检验与鉴别

印刷品同版鉴别作为印刷文件检验的技术手段,一直是文件检验鉴定领域的研究热点之一。由于胶印印刷方法的广泛应用,在各类案件中经常使用胶版印刷品的同版检验技术,本文首先介绍了平版胶印的基本原理,阐述了平版胶印文件的特征,从总观特征和细节特征两个方面论证了胶印同版检验鉴定问题,并结合案例重点讨论了同版印刷品的鉴别问题,最后说明了在进行胶印同版检验鉴定中,检验鉴定人员要有严谨细致的工作作风,只有充分发掘检材和样本上的细节特征后才可以科学、准确的给出鉴定结论。     

Dichroism measurements in forensic fibre examination: Part 3 — Dyed cotton and viscose fibres

A number of dyed cellulosic fibres were examined with plane polarized light on their dichroic behavior by microscopy and microspectrophotometry (MSP-PPL). Significant dichroic effects (mostly hypochromic effects and hypsochromic bands shifts) were reported. The effect is related to the chemical structure: some dye structures always possess dichroism (azo, stilbene, thiazole and oxazine), some dyes demonstrate sometimes dichroic effects (anthraquinoid, indigoid) while other structures never demonstrate dichroic effects (sulphur, diphenylmethanes, triarylmethanes, phthalocyanines). In some cases a different dichroic behavior was found for the same dyes applied on cotton and on viscose.