骨骼CT三维重建图像性别判定和年龄推断研究

目的通过计算骨骼计算机断层扫描(Computed Tomography,CT)三维重建图像判定性别和推断年龄的准确率,评价利用骨骼CT三维重建图像判定性别和推断年龄的可行性。方法将法医人类学教材中性别判定和年龄推断的方法应用于539例骨骼CT三维重建图像样本,判定245例骨盆的性别,推断100例男性耻骨联合、100例男性胸骨和94例男性锁骨的年龄,计算准确率。结果骨盆性别判定准确率为98.4%,耻骨下角和坐骨大切迹是区分性别最好的两项指标。男性耻骨联合、胸骨、锁骨的年龄推断准确率在45%以上,其中锁骨双侧方程准确率最高为77%。结论利用骨骼CT三维重建图像判定性别和推断年龄具有可行性。使用大体标本建立的骨盆形态学性别判定方法可直接应用于骨骼CT三维重建图像。使用大体标本建立的男性耻骨联合、胸骨、锁骨形态学年龄推断指标、分级和评分标准以及方程需要修改和补充。     

Variation in decomposition stages and carrion insect succession in a dry tropical climate and its effect on estimating postmortem interval

Insects have an important role in minimum postmortem interval (PMI_min) estimation. An accurate PMI_min estimation relies on a comprehensive study of the development and succession of local carrion insects. No published research on carrion insect succession exists for tropical north Queensland. To address this, we aimed to obtain preliminary observational data concerning the rate of decomposition and insect succession on pig carcasses in Townsville and compare these with other regions of Australia and overseas. Adult insects were collected daily from three pig carcasses for 30 d during summer and identified to family level. Observations of decomposition rate were made each day and progression through the stages of decomposition were recorded. Adult insects were identified to family and their presence/absence used as a proxy for arrival at/departure from the remains, respectively. These preliminary data highlight several interesting trends that may be informative for forensic PMI_min estimation. Decomposition was rapid: all carcasses were at the dry/remains stage by Day 5, which was substantially quicker than all other regions in the comparison. Differences were also observed in the presence/absence of insect families and their arrival and departure times. Given the rapid progression through early decomposition, we argue that later-arriving coleopteran taxa may be more forensically informative in tropical Australia, in contrast with temperate regions where Diptera appear most useful. This research contributes preliminary observational data to understanding insect succession patterns in tropical Australia and demonstrates the critical need for comprehensive local succession data for each climatic region of Australia to enable accurate PMI_min estimation. These data will inform future research targeted at gaining a more comprehensive understanding of insect succession in the Australian tropics.

Key points:

• We obtained preliminary observational data concerning the rate of decomposition and insect succession on pig carcasses in tropical Australia.
• Decomposition was rapid: all carcasses were at the dry/remains stage by Day 5.
• Coleopteran taxa may be more forensically informative in tropical Australia than dipterans.

     

The use of wildcards in forensic DNA database searches

Forensic genetic databases contain millions of DNA profiles worldwide. An allelic drop-out at a heterozygous locus (two different alleles) erroneously results in an observed homozygous profile. To guard against this, wildcards are induced for homozygous profiles. The wildcard represents any allele including the observed allele.In this paper, theoretical expressions for the number of matching loci are derived, results shown from a Danish dataset with more than 50,000 DNA profiles and simulations used to link homozygosity with the drop-out probability, which best mimics wildcard matching.     

我国刑事诉讼专家辅助人制度探析

由于缺乏相应的科学技术和专门性知识，诉讼当事人和司法人员不能对刑事诉讼鉴定意见进行科学评判。专家辅助人制度能够很好地解决鉴定意见在司法实践中存在的问题。但目前法律对专家辅助人制度规定得过于原则和粗糙，缺乏具体程序规范，这必然会给司法实践带来诸多困难。本文以专家辅助人制度的功能为逻辑出发点。探析了该制度的基础理论、运行规则以及相关的配套制度。     

Nonhuman forensic genetics

Forensic genetics is the application of genetics to human and nonhuman material for the resolution (and prevention) of legal conflicts. Nonhuman DNA applications are increasing, from the ancillary role in criminalistics to the control of protected species and their products, microbial identification in bioterrorism or medical malpractice. We review this growing applications’ scope and identify the major current difficulties, mainly resulting from the lack of standards and genetic databases as well as the poor or absent taxonomic definition of many major groups.     

The collapse of an Italian cemetery into the sea: Forensic approach to human remains identification

On February 22nd, 2021, a landslide on the Italian coast caused the collapse of an old cemetery. About 370 coffins tumbled and more than 200 fell into the sea. 333 groups of unidentified human remains were found: 140 decomposed bodies and 193 bags of commingled skeletal remains. The Medical Staff of Legal and Forensic Medicine was involved for analyzing the remains in order to identify and bury them. The remains involved belonged to people who died between the end of the XIX century and 2017; all were interesting by advanced transformative phenomena. For the identifications, new forms, based on the Interpol DVI ones, were created. Information was collected by relatives through a specific antemortem form. Relatives’ information and post-mortem data were compared: 19 body were identified thanks to secondary methods (like object in the bury, dresses, medical devices). 147 bone samples (long bones and teeth) were collected for the genetic analysis. Among the 77 relatives eligible for a genetic comparison, 66 gave consent to DNA swab for collection and genetic typing. Currently, after 48 samples DNA analysis (STRs and Y-polymorphism) 12 remains were identified, 21 presented a profile suitable for comparison but without attribution, and 7 did not return a comparable profile caused by stochastic effects. 31 subjects have been identified and the genetics analysis are still in progress. The Cemetery collapse shows that every disaster requires a tailored approach.     

Whitelisting system state in windows forensic memory visualizations

Examiners in the field of digital forensics regularly encounter enormous amounts of data and must identify the few artifacts of evidentiary value. One challenge these examiners face is manual reconstruction of complex datasets with both hierarchical and associative relationships. The complexity of this data requires significant knowledge, training, and experience to correctly and efficiently examine. Current methods provide text-based representations or low-level visualizations, but levee the task of maintaining global context of system state on the examiner. This research presents a visualization tool that improves analysis methods through simultaneous representation of the hierarchical and associative relationships and local detailed data within a single page application. A novel whitelisting feature further improves analysis by eliminating items of less interest from view. Results from a pilot study demonstrate that the visualization tool can assist examiners to more accurately and quickly identify artifacts of interest.     

Using previous DNA casework data to aid decision making in the process of DNA profile interpretation

In this study, a DNA decision support tool was developed. With this tool we aim to gain insight in what actions are performed with which (types of) DNA profiles in casework, to improve decision making by DNA experts in future cases.     

Analysis of genetic polymorphisms associated with the presence of freckles for phenotypic prediction

The prediction of externally visible characteristics (EVCs) is a commonly used practice by the forensic sciences as an important resource in the investigation of criminal cases in which the identity of perpetrators or victims is unknown or even to recognize decomposed cadavers. With this purpose, genetic markers associated with pigmentation traits have been widely studied by forensic scientists and, nowadays, it is possible to predict phenotypic characteristics such as hair, eyes and skin colour, as well as the presence of skin freckles by analysing single nucleotide polymorphisms (SNPs). In this study, we analysed the association of six SNPs located in pigmentation genes to the presence of freckles in individuals from the Brazilian population for forensic DNA phenotyping. The study was based within the context of a larger project on a population sample of 534 adult Brazilians of both sexes and different skin colours. DNA was extracted from peripheral blood and genotyped using the TaqMan® OpenArray® Real-Time PCR System (ThermoFischer Scientific) technique. Statistical analyses were carried out with the R software (version 4.0.2). As for the results obtained, three SNPs were shown to be statistically associated to the freckling, rs12203592, rs1800404 and rs222847, with CT, AG and AA genotypes being the main contributors, respectively. Variables such as sex of the individuals and skin colour were found to also contribute to the manifestation of this pigmentation trait. Further statistical analyses will be carried out to evaluate the possibility of using the SNPs in this study for phenotyping prediction of the Brazilian population, improving existing DNA phenotyping models in forensic sciences.     

Ethical analysis of a curious event of a forensic case becoming an involuntarily hospitalized psychiatric patient

It is not uncommon in forensic psychiatry that the duty to care for the patient conflicts with the responsibility to the court, or the duty to protect the public from harm from the potentially dangerous patient-offender. This paper exemplifies the scenario of what happens when the line between forensic and clinical psychiatry is crossed and whether crossing that boundary can be justified. Ethical discussion also embodies and clarifies the issues of unjustified violation of the patients’ autonomy and an undue infringement on their right to liberty on the arbitrary basis of existing or perceived mental illness. The paper provides an in-depth analysis of the issues of physicians’ conflicting duties, vulnerability of patient-offenders, and their human rights in the light of court orders and involuntary hospitalizations.

I argue that in order to promote ethical decision-making we must establish clear rules and guidelines for psychiatric practice, separate conflicting roles, and provide sufficient training of health-care professionals regarding topics of human rights and legislation governing clinical and forensic psychiatric practice. Empowering patients and enhancing their rights to autonomy and liberty can also be potent tools of promotion and protection of their human rights and prevention of ethical breaches in practice.