Forensic Science, Medicine and Pathology最新文献

A key criterion in dental age determination is the assessment of third molar mineralization. The objective of this study was to provide reference data for Demirjian stages D-H of teeth 38 and 48 in a northern Chinese population. To this end, 988 digital orthopantomograms (OPGs) of northern Chinese individuals aged 12-26 years were examined. Of the total sample, 822 OPGs showed at least one evaluable lower third molar. The mean ages for both teeth in males are above 18 years from stage G onwards. In females, the mean ages for both teeth are above 18 years from stage F onwards. The youngest individuals with mineralization stage H were older than 18.0 years in both sexes. Since studies with larger case numbers have also reported minimum ages for this stage below the age of 18, the minimum ages for stage H presented in this study cannot be recommended for age assessment practice. In order to avoid stage misclassifications, which are particularly problematic when applying the minimum age principle, stage classifications in future studies should be made consensually by experienced examiners.

Previous wound ballistics studies have examined the bullet's behavior while perforating gelatin. However, there has been limited attention to analyzing effects of bullet mass and energy transfer relating to magnitude and depth of the injurious temporary cavity with its clinical implications. Twenty-one bullets were fired into validated 20% synthetic ballistic gelatin with pressure transducers and high-speed videography. Bullet velocities, energy transfer, and maximum temporary cavities were calculated. Generalized linear models were developed to assess significant effects of bullet size, mass, and impact velocity for magnitude and depth of maximum pressure and temporary cavity diameter. A porcine femur was embedded in gelatin to demonstrate fracturing potential of the temporary cavity from an AR-15 5.56 NATO projectile. Maximum temporary cavity diameter and energy transferred expressed an exponential relationship (R² = 0.91). Bullet caliber (p = 0.039), bullet mass (p = 0.008), and impact velocity (p < 0.001) were significant predictors of maximum temporary cavity diameter. Bullet mass significantly influenced the depth of the maximum temporary cavity (p = 0.006), which expressed a moderate linear relationship (R² = 0.55). Substantially greater maximum pressure was observed in 30 - 06 caliber rounds from bolt action rifles and one fragmented AR-15 5.56 NATO projectile. The temporary cavity from an AR-15 5.56 NATO projectile was 17.1 cm in diameter and resulted in a complete middle diaphyseal wedge fracture of the femur with a bullet path 8.1 cm from the bone. Knowledge of relative magnitudes and locations of maximum temporary cavities may aid emergency physicians and trauma surgeons in identifying potential damage from gunshot wounds.

Environmental factors such as temperature, vertebrate and invertebrate activity and microbial succession patterns are important variables driving the decomposition process. However, the effects of low temperatures, specifically freezing on how a body decomposes are less understood. This pilot project aimed to determine the taphonomic effects of freezing on morphological changes during decomposition and the microbiome in an Australian context. Two human donors (one frozen, one non-frozen) and two frozen and two non-frozen Sus scrofa (pig) carcasses (n = 4) were allowed to decompose on the surface of woodlands for 12-weeks during summer 2017. Visual morphological changes were recorded, and microbial swabs were collected at regular intervals and analysed via real-time PCR to assess differences in bacterial community structure. Results indicated clear differences in decomposition patterns between frozen and non-frozen remains. Frozen remains were slow to enter 'early' decomposition but first to skeletonise. Microbial results suggest that patterns in community structure between bacteria may indicate if a body has been frozen at or around the time of death. This research suggests that quantifying the microbiome present during the fresh and early stages of decomposition and noting observations of an outside-in decomposition pattern may be a useful tool in identifying if remains have experienced extreme cold temperatures at the time of death. This knowledge could improve approaches to PMI estimation, particularly if the remains have experienced a freeze-thaw event after death.

With increasing migratory flows, forensic assessment of physical and psychological abuse plays an essential part for the proper functioning of humanitarian asylum procedures. Among professionals involved with vulnerable migrants, clinical forensic practitioners identify and assess injuries related to physical abuse and correlate them with the victims' narrative. The present study assesses the importance of a multidisciplinary approach to the final assessment of scars, analysing its impact on the medico-legal evaluation of asylum seekers who suffered physical abuse. A retrospective study was conducted on all cases of asylum seekers evaluated at the Milan University Institute of Legal Medicine from 2008 to 2020 to investigate in which cases further investigations were needed and the outcome impacts of these investigations. Of the individuals examined, 92 asylum seekers were subjected to further forensic instrumental examinations (80.4%) and specialized medical consultations (33.7%). The most common indication for further investigation was for blunt shape forces in combination with other forces (38%), followed by blunt force injuries alone (34.8%). Radiography was the most widely used instrumental examination indicated to investigate injuries (90%) and the most frequent further consultation was odontological (17.4%). In 62 cases (47.7%) the presence of scars was confirmed by the identification of further skeletal and visceral lesions. The present research highlights the direct impact of a multidisciplinary, specialist approach on forensic consistency findings. This approach facilitated and improved the accuracy of clinical forensic evaluation in these highly sensitive cases, thereby reducing errors when assessing the presence of confounding factors, including those consequent from healing processes.

Middle Eastern and African populations make up a significant portion of the global population and exhibit substantial genetic diversity. However, genetic studies on these populations have been largely underrepresented compared to other populations. This study analysed published Y-STR data for 186 populations and regions, including 14,504 individuals from 52 Middle Eastern and 134 African populations. The highest genetic diversity was found at the DYS458 locus in the Middle East and North Africa, and at the DYS385b locus in other African regions. Multidimensional scaling (MDS) analysis and genetic distance calculations between Middle Eastern and African populations revealed five distinct clusters. The Arabian Peninsula countries formed two small clusters, while most African countries formed two mains centrally located clusters. The most common haplogroups in the Middle Eastern populations were J1a (29.4%), while in the African populations, E1b1a (43.2%) was the most prevalent. This study examined two allelic richness parameters: distinct and private alleles. Central Africa showed the highest levels of distinct alleles, with the Middle East having the third-highest level. The prevalence of private alleles in the Middle East was moderate, lower than South Africa but higher than North Africa. A population Q-matrix graph was constructed, yielding 10 clusters (K = 10) that identified population clusters in the Y-STR data corresponding to specific geographical regions and revealed stronger sub-grouping of countries within each population.

Background: PMCT findings can vary considerably with the postmortem interval (PMI), potentially complicating the assessment of pulmonary thromboembolism (PTE). Although attenuation changes in antemortem thrombi have been investigated, the postmortem evolution of thrombus imaging characteristics remains insufficiently characterized.

Case presentation: We present the case of a man in his 70s who died of PTE. Serial non-contrast PMCT was performed at 1 h and 96 h postmortem. On the initial scan, the thrombus in the left pulmonary artery measured 45 Hounsfield units (HU), while the adjacent vascular lumen measured 58 HU. On the delayed scan, thrombus attenuation increased to 70 HU, while vascular lumen attenuation decreased to 30 HU. Consequently, the contrast ratio between thrombus and lumen increased from 13% to 40%, thereby enhancing thrombus conspicuity. At autopsy, bilateral pulmonary artery thromboemboli were confirmed.

Discussion: The progressive enhancement in thrombus conspicuity over time may reflect postmortem physiological processes such as plasma separation and hypostasis, contrasting with the attenuation decline typically described in antemortem thrombi. Despite potential variability of CT acquisition parameters, relative attenuation differences may provide more reliable diagnostic information.

Conclusion: To our knowledge, this is the first report to demonstrate time-dependent imaging evolution of pulmonary thromboemboli using serial non-contrast PMCT. Recognition of such temporal imaging alterations may enhance the diagnostic utility of PMCT and guide the development of time-sensitive postmortem imaging protocols in forensic radiology.

The aim of our research was to determine the progression of postmortem ocular changes, focusing on the retina and sclera, over a specified time period and to assess whether these changes are influenced by environmental or physiological factors. Twelve Wistar rats were divided into four experimental groups based on postmortem interval (PMI): immediate autopsy (control), 24 h, 48 h, and 72 h. The mechanism of death was asphyxia by hanging. Each eye sample was macroscopically and microscopically monitored for retinal and scleral changes depending on the PMI and eye exposure (open vs. closed). The most pronounced ocular changes were observed at the longest PMI, including complete loss of retinal stratification, degeneration of ganglion cells, and infiltration by mononuclear inflammatory cells. Similar degenerative changes were observed in the scleral epithelium, particularly in open eyes. This experimental model provides a foundational framework for studying postmortem ocular changes, particularly in the retina and sclera, and may enhance the accuracy of PMI estimation in forensic investigations.

Medicolegal forensic entomology relies largely on blow fly (Diptera: Calliphoridae) activity to estimate a minimum postmortem interval (mPMI). The prevailing assumption, that blow flies are inactive at night, leads to the exclusion of nocturnal colonization from mPMI estimates. Artificial light at night (ALAN), however, especially from the increasing use of light emitting diode (LED) streetlights, may alter this innate behavior. Baited traps were deployed at two sites: one natural site that was dark at night (unlit) and one undeveloped but with infrastructure site that was LED-illuminated at night (lit). Samples were collected during daytime and nighttime periods. A total of 1,544 blow flies representing seven species were collected. Only six flies (0.4% of the total) were captured at night, four in unlit and two in lit environments, indicating minimal nighttime activity. These results suggest that, under current conditions, ALAN is unlikely to induce nocturnal blow fly behavior and impact mPMI estimations. Further research across diverse taxa and environments is needed to better understand the effects of ALAN on insects of forensic importance.