An innovative transfer DNA experimental design and qPCR assay: Protocol and pilot study

Forensic “touch” DNA samples are low-quantity samples that are recovered from surfaces that have been touched by single or multiple individuals. These samples can include DNA from primary contributors who directly touched the surface, as well as secondary contributors whose DNA was transferred to the surface through an intermediary. It is difficult to determine the type of transfer, or how often and under what conditions DNA transfer occurs. In this paper, we present an innovative protocol that combines (1) a paired male and female transfer DNA experimental design in which the presence of male DNA indicates secondary transfer and (2) a cost-effective quantitative PCR (qPCR) assay of a sex-specific region in the Amelogenin gene to detect male and female DNA. We evaluate the ability of the Amelogenin qPCR assay to detect low concentrations of male and female DNA in mixed samples. We also test experimental DNA samples using our transfer DNA protocol to differentiate primary and secondary DNA transfer. Male DNA was detected in the majority of known mixed samples, even in samples with 4× more female DNA—this result demonstrates the ability to detect low concentrations of male DNA and the presence of secondary transfer DNA in our experimental design. Primary DNA transfer was detected in 100% of our experimental trials and secondary DNA transfer was detected in 37.5% of trials. Our innovative protocol mimics realistic case scenarios to establish rates of primary and secondary DNA transfer in an inexpensive and simplified manner.     

False-negative probability in the SEM/EDS automated discovery of iGSR particles: A Bayesian approach

The automated search software integrated with a scanning electron microscope (SEM/EDS) has been the standard tool for detecting inorganic gunshot residues (iGSR) for several decades. The detection of these particles depends on various factors such as collection, preservation, contamination with organic matter, and the method for sample analysis. This article focuses on the influence of equipment resolution setup on the backscattered electron images of the sample. The pixel size of these images plays a crucial role in determining the detectability of iGSR particles, especially those with sizes close to the pixel size. In this study, we calculated the probability of missing all characteristic iGSR particles in a sample using an SEM/EDS automated search and how it depends on the image pixel resolution setup. We developed and validated an iGSR particle detection model that links particle size with equipment registers and applied it to 320 samples analyzed by a forensic science laboratory. Our results show that the probability of missing all characteristic iGSR particles due to their size is below 5% for pixel sizes below 0.32 μm². These findings indicate that pixel sizes as large as twice the one commonly used in laboratory casework, that is, 0.16 μm², are effective for initial sample scanning, yielding good detection rates of characteristic particles that could exponentially reduce laboratory workload.     

The applications of MicroCT in studying age-related tooth morphological change and dental age estimation: A scoping review

Conventional dental age estimation relies on destructive methods such as sectioning and staining, which are unpreferable when the tooth is required for evidential or archeological preservation. MicroCT is a non-destructive, high-resolution imaging technique that allows for accurate morphometrical measurement. Although microCT technology has been applied in a variety of dental studies, studies focusing on dental age-related change and dental age estimation based on microCT imaging remain lacking. Based on the question: “How has microCT technology been applied in studying human age-related tooth morphological change and dental age estimation studies?”, the authors conducted a scoping review in accordance with the Arksey and O'Malley (2005) and the PRISMA-ScR guidelines. A literature search using five major scientific databases identified 452 articles, with 11 full-text articles being eligible to be included in the scoping review. Furthermore, 6 out of the 11 studies performed dental age estimation modeling. An overview of the parameters used in the selected articles revealed a variety of tooth characteristics, such as pulp cavity to whole tooth volume ratio, secondary dentin, as well as the diameter of root canal orifice. The findings of this scoping review highlight the extent microCT is used in studying dental age-related changes, as well as the effectiveness of microCT in dental age estimation studies. This review serves as a guide for future forensic odontology age estimation studies.     

Comment on the Marshall-Hoare-Henssge model for estimating the time since death

Timewise temperature variations in objects that are undergoing unsteady heating or cooling is a commonly encountered problem in the thermal sciences. One particular area of application is the cooling of a body post-death and the use of body temperatures to estimate the time of death. Here, a new approach based on the theory of transient heat transfer is formulated to allow efficient calculation of unsteady conduction problems. The theoretically derived unsteady temperature models are compared with experimentally based correlations (the Marshall-Hoare-Henssge model). The two approaches are found to agree very well. With this new theoretically based approach, timewise temperature variation can be calculated for both large and small Biot number transient problems.     

IoT forensics: Exploiting unexplored log records from the HIKVISION file system

CCTV surveillance systems are IoT products that can be found almost everywhere. Their digital forensic analysis often plays a key role in solving crimes. However, it is common for these devices to use proprietary file systems, which frequently hinders a complete examination. HIKVISION is a well-known manufacturer of such devices that typically ships its products with its proprietary file system. The HIKVISION file system has been analyzed before but that research has focused on the recovery of video footage. In this paper, the HIKVISION file system is being revisited regarding the log records it stores. More specifically, these log records are thoroughly examined to uncover both their structure and meaning. These unexplored pieces of evidence remain unexploited by major commercial forensic software, yet they can contain critical information for an investigation. To further assist digital forensic examiners with their analysis, a Python utility, namely the Hikvision Log Analyzer, was developed as part of this study that can automate part of the process.     

中日两国在东亚区域内贸易中地位的变化及其影响

东亚区域内贸易比重的迅速上升是现阶段东亚贸易发展的一个重要特征。中国和日本作为东亚区域内两个最大的经济体,两国在东亚区域内贸易中的地位和影响力的变动对相互之间的经济合作以及区域内经济合作模式的选择,具有十分重大的影响。本文在分析东亚区域内贸易发展现状的基础上,从中间产品和最终产品的贸易结构与贸易竞争压力的角度,分析了中日两国在东亚区域内贸易中地位的变动及其影响。     

国际海盗问题与中国海上通道安全

作为世界贸易大国和能源进口大国,中国的发展越来越依赖于海外,海上通道安全对保障中国国家安全的重要性日益凸显。海盗作为一种国际犯罪行为,严重影响国际海上航运安全,也对中国海上战略通道安全构成现实威胁。海盗治理成为关系到中国海上通道安全的重大问题,必须采取积极有效措施加以解决。为此,我们必须进一步完善国内反海盗立法和反海盗机制;充分发挥联合国的作用,建立打击海盗、维护海上通道安全的长效机制;积极推动反海盗的国际和地区合作;增强防御海盗的力量和意识,重视远洋海军建设;坚持标本兼治,积极推进海盗所属国或地区的和平、发展和稳定。     

Psychiatric disorders and management of sexual offenders in the prison psychiatric consultation unit of Marseille

Since 2017, complaints of sexual violence have increased in France. At the same time, the management of sexual offenders has been at the center of international public health policies. The prevalence of mental disorders among sexual offenders is an essential field of research. There are some published studies on the prevalence of psychiatric disorders in sexual offenders in detention, but there are few recent published studies among French individuals who were detained. Our objectives were to determine the prevalence of psychiatric disorders among persons detained for sexual offenses and the level of care received according to their diagnosis. For this purpose, we carried out a retrospective observational study from January 2017 to October 2021 of all adult sexual offenders, whether accused or convicted, who were seen in the psychiatric consultation unit of Les Baumettes prison, Marseille, France. The primary outcome measure was the psychiatric diagnosis entered in the medical records. One hundred forty-two patients were included in analysis. All patients were men, and the majority (n = 97, 68.3%) of these patients presented with at least one psychiatric disorder, principally a personality disorder (31.7%). 10.6% presented with a schizophrenic disorder, 4.9% a bipolar disorder, 3.5% a depressive disorder, 5.6% pedophilic paraphilia, and 25.4% an addictive disorder. Their management and comorbid addictions were analyzed in subgroups for each psychiatric disorder. Patients appeared to receive an appropriate level of care for their diagnosed disorder. It seems important to develop structured assessment of recidivism risk for better management of sexual offenders.     

The systemic error in the vertical component of handgun bullet trajectory reconstructions

Establishing the path or trajectory of a fired bullet is an often recurring part of shooting incident reconstruction. The current study describes how gravitational pull causes a systemic error on the vertical component of a trajectory reconstruction. Bullet drop, drop angle, and vertical offset are explained and calculated for 10 different handgun/ammunition combinations over a range of distances up to 100 m. The presented results are intended to provide forensic firearm examiners with a reference frame for the magnitude of error introduced on handgun bullet trajectory reconstructions over distance. Threshold values of 20 and 30 m are proposed as conservative distances up to where bullet trajectories can be modeled as straight lines with subsonic/transonic handgun bullets and with supersonic handgun bullets respectively. Both the bullet drop and vertical offset will be below 5 cm at these distances for those categories. The drop angle will be below 0.3°.