Gait analysis in forensic medicine*

Recordings from video surveillance systems are used as evidence from crime scenes. It would be useful to perform comparisons between disguised perpetrators and suspects based on their gait. We applied functional anatomical and biomechanical knowledge to analyze the gait of perpetrators, as recorded on surveillance video. Using a structured checklist, which addresses the single body segments during gait, we were able to give a statement concerning the gait patterns. Characteristic parameters were, e.g., varus instability in the knee at heel strike, and larger lateral flexion of the spinal column to one side than the other. Based on these characteristic features, we are able to state with reasonable certainty whether the suspect could be the perpetrator, but it is not possible to identify the perpetrator positively. Nevertheless, we have been involved in several cases where the court has found that this type of gait analysis was a valuable tool.     

智能型物证管理系统的应用

加强物证保管工作,是推进执法规范化建设的迫切需要,是适应法制建设的迫切需要,是提高我国公安机关执法办案质量的迫切需求。本文针对当前国内刑事科学技术工作中物证保管存在的问题,研究并建立了智能型物证管理系统,对加强新时期刑事科学技术工作具有指导意义。     

美国法庭科学证据的应用与发展

＂法庭科学＂萌芽于古代中国,兴盛于近现代西方国家,最终发展成为具备完整科学体系的现代意义上的法庭科学学科。法庭科学证据的应用与发展显然与法庭科学的发展与应用密切相关,它们相互制约,相互促进。美国司法制度中关于法庭科学证据的证明力、可信度、可采性的分立质疑对法庭科学本身的发展无疑起到鞭策与促进作用。美国法庭科学证据的司法制度以及常用的一些传统与高技术法庭科学证据的使用过程中存在的许多问题,理解法庭科学证据标准,对我国法庭科学及其证据的研究与应用有所启迪。     

从证据学角度探讨法医学及其分支学科的重新定义

从证据学角度,对法医学及其分支学科进行了重新定义和划分。同时,为了从人文科学和自然科学两个方面理顺法医学的学科定位,尝试澄清了＂证据科学＂与＂法（庭）科学＂、＂应用医学＂与＂特种医学＂等相关上下位学科和平行学科的概念。     

Heel-ball (HB) index: sexual dimorphism of a new index from foot dimensions

The present research is aimed to introduce Heel-ball (HB) index from foot dimensions and determine whether this index exhibits sexual dimorphism. The study was conducted on a sample of 303 North Indian individuals (154 men, and 149 women) aged between 13 and 18 years. The stature, body weight, foot breadth at the ball (BBAL), and foot breadth at heel (BHEL) were measured. The HB index was derived by the formula BHEL × 100/BBAL. Although the mean HB index was larger in women in both feet it showed statistically significant sex differences in the right foot only. The study shows that while the foot dimensions show a positive correlation with stature and weight, the HB index is independent of the stature and weight of an individual. This novel index (HB index) may be utilized in sex determination when a part of the foot is brought for medico-legal investigation.     

Single cells for forensic DNA analysis--from evidence material to test tube

Abstract: The purpose of this project was to develop a method that, while providing morphological quality control, allows single cells to be obtained from the surfaces of various evidence materials and be made available for DNA analysis in cases where only small amounts of cell material are present or where only mixed traces are found. With the SteREO Lumar.V12 stereomicroscope and UV unit from Zeiss, it was possible to detect and assess single epithelial cells on the surfaces of various objects (e.g., glass, plastic, metal). A digitally operated micromanipulator developed by aura optik was used to lift a single cell from the surface of evidence material and to transfer it to a conventional PCR tube or to an AmpliGrid^® from Advalytix. The actual lifting of the cells was performed with microglobes that acted as carriers. The microglobes were held with microtweezers and were transferred to the DNA analysis receptacles along with the adhering cells. In a next step, the PCR can be carried out in this receptacle without removing the microglobe. Our method allows a single cell to be isolated directly from evidence material and be made available for forensic DNA analysis.     

On using gait in forensic biometrics

Given the continuing advances in gait biometrics, it appears prudent to investigate the translation of these techniques for forensic use. We address the question as to the confidence that might be given between any two such measurements. We use the locations of ankle, knee, and hip to derive a measure of the match between walking subjects in image sequences. The Instantaneous Posture Match algorithm, using Harr templates, kinematics, and anthropomorphic knowledge is used to determine their location. This is demonstrated using real CCTV recorded at Gatwick International Airport, laboratory images from the multiview CASIA-B data set, and an example of real scene of crime video. To access the measurement confidence, we study the mean intra- and inter-match scores as a function of database size. These measures converge to constant and separate values, indicating that the match measure derived from individual comparisons is considerably smaller than the average match measure from a population.     

Is There a Correlation Between Footstep Length,Lower Extremities,and Stature?, ,

A probable correlation between stature and footstep length is expected, and consequently, the stature may be estimated from footstep length. The present research was conducted to study the correlation of footstep length with length of the lower extremities and stature. The study participants (n = 142) were asked to walk on a paper sheet with inked feet and footstep length was measured. Mean stature and lower limb length were significantly larger in males. Sex differences were not observed in the average footstep length. Average footstep length and lower limb length did not show a significant correlation among the participants. A statistically significant correlation was observed between average footstep length and stature only among females. Our observations suggest that the length of the lower limb may not be a major factor in determining the footstep length of a person and that the forensic utility of stature estimation from footstep length may be limited.     

Value of DNA tests: a decision perspective

ABSTRACT: Before a Court of Law testifying in DNA‐evidence cases, scientists are often challenged with the idea that the more markers (loci) the better, i.e., why does the scientist not use 16 or more markers? This paper introduces a new perspective, decision analysis, to deal with the problem of the number of markers to type in a criminal context. The decision‐making process, which plays a key role in the routine work of a forensic scientist, consists of the rational choice, given personal objectives, between two or more possible outcomes when the consequences of the choice are uncertain. Simulated results support the hypothesis that analytical added value does not increase with the number of markers.     

拉曼光谱技术在物证鉴定中的应用

拉曼光谱技术具有不接触样品、不破坏样品、无需样品制备等优点,适用于法庭科学领域不同种类物证的分析.本文综述了拉曼光谱技术在物证鉴定中的应用,并对该技术的发展趋势进行了展望.     

植物检验在司法鉴定中的应用

植物在自然界分布广泛,与人类生活密切相关,容易与各类诉讼活动发生联系而成为物证。为了提高对植物检验重要性的认识,作者对植物检验技术及其司法鉴定应用价值进行了探讨。     

Performance testing of commercial containers for collection and storage of fire debris evidence

Fire debris evidence may contain ignitable liquid residues valuable in the investigation of a potential arson scene. The ability to obtain evidence containers that are contaminant-free and vapor-tight is essential to the analysis and storage of fire debris evidence. Commercial containers such as metal "paint" cans, glass mason jars, and polymer bags are often employed as fire debris evidence containers. The purpose of this research was to determine which of these three types of containers provided the most vapor-tight seal for the prevention of ignitable liquid vapor loss and to assess the potential for cross-contamination. Leak rates for each type of container were measured under controlled conditions. Simple mixtures of hydrocarbons were utilized in these experiments. Leak rates were determined based on the amounts of hydrocarbon recovered from activated charcoal located outside the test container and within a secondary container. Quantitation of the hydrocarbons recovered from activated charcoal was calculated using external standard calibration curves following analysis by gas chromatography-mass spectrometry. The results demonstrated that glass jars had the fastest leak rate followed by metal paint cans and properly heat-sealed polymer bags with the slowest leak rate. Each container exhibited a different leak mechanism, which resulted in an observable effect on the composition of hydrocarbons lost from the container. Hydrocarbon transfer from one container to another is also demonstrated. This study presents results that reveal the most vapor-tight container to be a properly heat-sealed copolymer bag.