International Journal of Legal Medicine最新文献

DNA mixture analysis poses a significant challenge in forensic genetics, particularly when dealing with degraded and trace amount DNA samples. Multi-SNPs (MNPs) are genetic markers similar to microhaplotypes but with smaller molecular sizes (< 75 bp), making them theoretically more suitable for analyzing degraded and trace amount samples. In this case report, we investigated a cold case involving a campstool stored for over a decade, aiming to detect and locate the suspect's DNA. We employed both conventional capillary electrophoresis-based short tandem repeat (CE-STR) analysis and next-generation sequencing-based multi-SNP (NGS-MNP) analysis. The typing results and deconvolution of the mixed CE-STR profiles were inconclusive regarding the presence of the suspect's DNA in the mixed samples. However, through NGS-MNP analysis and presence probability calculations, we determined that the suspect's DNA was present in the samples from Sect. 4-1 with a probability of 1-8.41 × 10^- 6 (99.999159%). This evidence contradicted the suspect's statement and aided in resolving the case. Our findings demonstrate the significant potential of MNP analysis for examining degraded and trace amount DNA mixtures in forensic investigations.

Necrophagous flies, particularly blowflies, serve as vital indicators in forensic entomology and ecological studies, contributing to minimum postmortem interval estimations and environmental monitoring. The study investigates variations in the predominant cuticular hydrocarbons (CHCs) viz. n-C25, n-C27, n-C28, and n-C29 of empty puparia of Calliphora vicina Robineau-Desvoidy, 1830, (Diptera: Calliphoridae) across diverse environmental conditions, including burial, above-ground and indoor settings, over 90 days. Notable trends include a significant decrease in n-C25 concentrations in buried and above-ground conditions over time, while n-C27 concentrations decline in buried and above-ground conditions but remain stable indoors. Burial conditions show significant declines in n-C27 and n-C29 concentrations over time, indicating environmental influences. Conversely, above-ground conditions exhibit uniform declines in all hydrocarbons. Indoor conditions remain relatively stable, with weak correlations between weathering time and CHC concentrations. Additionally, machine learning techniques, specifically Extreme Gradient Boosting (XGBoost), are employed for age estimation of empty puparia, yielding accurate predictions across different outdoor and indoor conditions. These findings highlight the subtle responses of CHC profiles to environmental stimuli, underscoring the importance of considering environmental factors in forensic entomology and ecological research. The study advances the understanding of insect remnant degradation processes and their forensic implications. Furthermore, integrating machine learning with entomological expertise offers standardized methodologies for age determination, enhancing the reliability of entomological evidence in legal contexts and paving the way for future research and development.

STR loci localized on the X chromosome provide information additional to the autosomal markers routinely analyzed in forensic genetics, integrating genetic systems as Y-STRs and mitochondrial DNA in the investigation of complex kinship scenarios and mass disaster cases.In this study we genotyped 12 X-STR loci in 251 male samples from four populations of Namibia in southern Africa using the Investigator Argus X-12 kit (Qiagen, Hilden, Germany). Forensic efficiency parameters indicated high power of discrimination in the considered populations. As part of our investigation, we highlighted partial linkage associations between loci within known linkage groups (LGs) and identified several occurrences of previously unreported out-of-ladder (OL) alleles.Genetic distances between the Namibian populations here investigated and other African (Eritrea, Ethiopia, Somalia, Guinea, Cape Verde) and non-African (Germany, China, Philippines) populations using loci grouped in LGs mirrored their biogeographical distribution differently for each linkage group. Haplotype sharing within each LG revealed a high degree of population-specific types, hinting to the potential of these markers for ancestry applications.These results highlight the importance to produce specific and freely available population databases especially for multi-ethnic countries. This novel dataset is expected to be of interest for population studies that need an accessible reference dataset of African regions not currently well represented, as well as possible relevance for forensic applications focusing on the biogeographic origin of samples.

Age estimation in forensic odontology is mainly based on the development of permanent teeth. To register the developmental status of an examined tooth, staging techniques were developed. However, due to inappropriate calibration, uncertainties during stage allocation, and lack of experience, non-uniformity in stage allocation exists between expert observers. As a consequence, related age estimation results are inconsistent. An automated staging technique applicable to all tooth types can overcome this drawback.This study aimed to establish an integrated automated technique to stage the development of all mandibular tooth types and to compare their staging performances.Calibrated observers staged FDI teeth 31, 33, 34, 37 and 38 according to a ten-stage modified Demirjian staging technique. According to a standardised bounding box around each examined tooth, the retrospectively collected panoramic radiographs were cropped using Photoshop CC 2021® software (Adobe®, version 23.0). A gold standard set of 1639 radiographs were selected (n₃₁ = 259, n₃₃ = 282, n₃₄ = 308, n₃₇ = 390, n₃₈ = 400) and input into a convolutional neural network (CNN) trained for optimal staging accuracy. The performance evaluation of the network was conducted in a five-fold cross-validation scheme. In each fold, the entire dataset was split into a training and a test set in a non-overlapping fashion between the folds (i.e., 80% and 20% of the dataset, respectively). Staging performances were calculated per tooth type and overall (accuracy, mean absolute difference, linearly weighted Cohen's Kappa and intra-class correlation coefficient). Overall, these metrics equalled 0.53, 0.71, 0.71, and 0.89, respectively. All staging performance indices were best for 37 and worst for 31. The highest number of misclassified stages were associated to adjacent stages. Most misclassifications were observed in all available stages of 31.Our findings suggest that the developmental status of mandibular molars can be taken into account in an automated approach for age estimation, while taking incisors into account may hinder age estimation.

Thanks to technical progress and the availability of virtual data, sex estimation methods as part of a biological profile are undergoing an inevitable evolution. Further reductions in subjectivity, but potentially also in measurement errors, can be brought by approaches that automate the extraction of variables. Such automatization also significantly accelerates and facilitates the specialist's work. The aim of this study is (1) to apply a previously proposed algorithm (Kuchař et al. 2021) to automatically extract 10 variables used for the DSP2 sex estimation method, and (2) to test the robustness of the new automatic approach in a current heterogeneous population. For the first aim, we used a sample of 240 3D scans of pelvic bones from the same individuals, which were measured manually for the DSP database. For the second aim a sample of 108 pelvic bones from the New Mexico Decedent Image Database was used. The results showed high agreement between automatic and manual measurements with rTEM below 5% for all dimensions except two. The accuracy of final sex estimates based on all 10 variables was excellent (error rate 0.3%). However, we observed a higher number of undetermined individuals in the Portuguese sample (25% of males) and the New Mexican sample (36.5% of females). In conclusion, the procedure for automatic dimension extraction was successfully applied both to a different type of data and to a heterogeneous population.

Objective: Our research was aimed to establish the equation and to determine its precision for dental age estimation in adolescents, adults and the elderly based on the thickness of deposited dental cement.

Design: The study sample consisted of 206 donor teeth of both sexes (10 to 82 years of age). The roots were transversely cut (6 cuts) on an ISOMET 1000 cutter at apical, middle, and cervical parts (slice thickness 0.3 to 0.5 μm). Measurements of cement thickness on incisions were made with a light microscope and an Olympus EP50 camera with previous microscope calibration for each measurement episode. Measurements were carried out clockwise at 4 measuring points on each incision. Statistical analyses were conducted using statistical software packages STATISTICA version 12.0 StatSoft, Inc. 2013, and MedCalc^® version 22.0.

Results: Mean cement thickness (MCT) significantly declined from apical to cervical cuts (P < 0.001, ANOVA) and was thicker in teeth with a destroyed tooth crown (P < 0.001, ANOVA) and in molars compared to incisors (P < 0.001, ANOVA). MCT was greater in men and in teeth with more than one root but without reaching statistical significance. MCT showed a significant increase from the second decade of chronological age with a peek at sixth decade and declined to the ninth decade (P < 0.001, ANOVA). Piecewise linear regression defined a breakpoint age of 53 years, so two different equations were calculated (≤ 53 years and > 53 years).

Conclusions: The resulting equation is recommended for estimating dental age in forensic analyses.

Background: Stress hormones like catecholamine and cortisol are thought to reflect the magnitude of physical stress in adults and were studied in relationship to the cause of death and agony time. Intrauterine distress, intrapartum events, and modes of delivery can affect the fetal endocrine stress response, as reflected by biochemical analyses. The aim of the present study was to evaluate the role of catecholamines and cortisol as markers of ante-mortem fetal distress. The role of cortisol as a marker of circadian timing of delivery was also assessed.

Methods: A 2-year prospective cohort-comparison inclusion of stillbirths and newborns took place with collection of antemortem data, labor parameters, neonatal outcome, post-mortem data and blood samples. Stillbirths were classified as acute or chronic on the basis of a multidisciplinary evaluation. Heart blood of stillbirths and cord blood of newborns were analyzed by high pressure liquid chromatography (HPLC) for adrenaline and noradrenaline and by immunoassay for cortisol determination.

Results: Fifteen stillbirths and 46 newborns, as a comparison group, delivered by spontaneous vaginal birth, elective, and emergency cesarean sections were included. Stillbirths' main cause of death was cord thrombosis. Levels of adrenaline and noradrenaline (median: 14,188 pg/ml and 230.5 pg/ml, respectively) were significantly higher (p < 0.001) in stillbirths than in newborns and were also higher in acute compared to chronic distress. Cortisol levels were significantly higher (p < 0.05) in spontaneous vaginal delivery (median: 18.2 μg/dl) compared to elective cesarean sections (median: 3.8 μg/dl). No difference in cortisol concentrations was detected between newborns delivered at morning and at afternoon/evening.

Conclusion: Our results suggest that the biochemical measurement of adrenaline and noradrenaline levels might reflect a marked physical stress response during the process of death in stillbirths. On the contrary, the elevation of cortisol levels could mirror the elevation in maternal cortisol level during vaginal delivery. For the post-mortem evaluation of stillbirths, the analysis of CA levels could provide additional data on the duration of distress, useful to integrate the forensic diagnosis.

The timing of dental development in ethnic Finns and Somalis, who were born and living in Finland, was compared, with efforts to minimize environmental bias. The developmental status of seven lower left permanent teeth were staged according to Demirjian et al., using panoramic radiographs from 2,100 Finnish and 808 Somali females and males, aged 2 to 23 years. For each tooth, a continuation-ratio model was constructed to analyze the allocated stages as a function of sex and ethnic origin. Several statistically significant differences in mean age of certain tooth developmental stage transitions were revealed. While Somalis generally displayed stage transitions at younger age, none of the seven teeth consistently showed earlier stage transitions in Somalis compared to Finns. Within each tooth, the lowest (or highest) mean age of stage transition varied without any discernible pattern between the two ethnic groups. Overall, the observed differences in mean age of stage transition between the groups was minimal, suggesting a low impact on clinical and forensic age assessment practice. In conclusion, the studied ethnic Finn and Somali groups with equal nutritional and /or environmental conditions exhibit similar timing in the development of all lower left permanent teeth.

Pursuing a proficient age estimation methodology introducing novel radiographic methods remains an ongoing and demanding aspect of forensic and medicolegal research. In 2017, Roberts GJ et al. (J Forensic Sci 62(2):351-4, 2017) described a new radiographic method, i.e., root canal width (RCW) patterns to assign a subject to above 18-year-age threshold. Since then, few researchers have investigated the validity of this radiographic method in other populations. The present study aimed to test the usefulness of these RCW patterns in predicting 18 years in a sample of South Indian juveniles and sub-adults aged between 16 and 23. Descriptive analysis revealed that pattern-A was initially observed at a minimum age of 16.08 and 16.22 years in males and females. Pattern-B at 16.31 years in males and 16.22 years in females, while pattern-C was initially recorded at 18.73 years in males and 19.01 years in females, respectively. In summary, if an individual, regardless of sex, exhibits a fully-formed (apex closed) mandibular first, second, and third molars and concurrently displays RCW-C, there is a strong likelihood that the person has exceeded the legally relevant age of 18 years. However, due to higher rate of technically unacceptable errors (adults wrongly identified as individuals below 18 years), reliance on this method alone should be restricted, and it is advisable to combine it with other methods.

Background: A growing number of studies investigated the factors that contribute to driving under the influence (DUI) of alcohol in relation to gender. However, a gendered approach of the scientific evidence is missing in the literature. To fill this gap, a gender-driven systematic review on real case studies of the last two decades was performed. In addition to the gender of the drivers involved, major independent variables such as the period of recruitment, the type of drivers recruited, and the geographical area where the study was conducted, were examined. Afterwards, a meta-analysis was performed comparing alcohol-positive rates (APR) between male and female drivers in three subgroups of drivers: those involved in road traffic accidents, those randomly tested on the road, and volunteers.

Methods: Three databases were searched for eligible studies in October 2023. Real-case studies reporting APR in man and women convicted for DUI of alcohol worldwide were included. Univariate analysis by ANOVA with post-hoc tests identified the independent variables with a significant impact on the dependent variable APR, according to a relationship subsequently investigated by standard multiple linear regression. The meta-analysis of random effects estimates was performed to investigate the change in overall effect size (measured by Cohen's d standardized mean difference test) and 95% confidence interval (CI).

Results: Among papers addressing driver gender, univariate analysis of independent variables revealed a higher Alcohol Positive Rate (APR) in men, particularly in drivers involved in crashes, with a noticeable decrease over time. Analyzing the gender of drivers involved in crashes, the meta-analysis showed that men had a significantly higher APR (30.7%; 95%CI 26.8-35.0) compared to women (13.2%; 95%CI 10.7-16.1). However, in drivers randomly tested, there was no significant difference in APR between genders (2.1% for men and 1.4% for women), while in volunteers, there was a statistically significant difference in APR with 3.4% (95%CI 1.5-7.6) for men and 1.1% (95%CI 0.5-2.7) for women.

Conclusion: Despite a progressive decrease in the epidemiological prevalence of alcohol-related DUI over time, this phenomenon remains at worryingly high levels among drivers involved in road traffic accidents in both genders, with a higher prevalence in men. It's important for policymakers, professionals, and scientists to consider gender when planning research, analysis, interventions, and policies related to psychoactive substances, such as alcohol or other licit drugs. Forensic sciences can play a vital role in this regard, enabling a thorough analysis of gender gaps in different populations.