International Journal of Legal Medicine最新文献

Most of the sexual assault casework samples are of mixed sources. Forensic DNA laboratories are always in the requirement of a precise technique for the efficient separation of sperm and non-sperm DNA from mixed samples. Since the introduction of the differential extraction technique in 1985, it has seen significant advancements in the form of either chemicals used or modification of incubation times. Several automated and semi-automated techniques have also adopted the fundamentals of conventional differential extraction techniques. However, lengthy incubation, several manual steps, and carryover over non-sperm material in sperm fraction are some of the major limitations of this technique. Advanced cell separation techniques have shown huge promise in separating sperm cells from a mixture based on their size, shape, composition, and membrane structure and antigens present on sperm membranes. Such advanced techniques such as DEParray, ADE, FACS, LCM, HOT and their respective pros and cons have been discussed in this article. As current-day forensic techniques should be as per the line of Olympic slogan i.e., faster, higher, stronger, the advanced cell separation techniques show a huge potential to be implemented in the casework samples.

In forensic age estimation, CT imaging of the clavicles is used to determine an age over completed 21 years. If ossification of the medial clavicular epiphysis is complete, young men are assumed to be over 21 years of age. The aim of this study is to check the statistical parameters (specificity, predictive probability) for the characteristic "completed ossification of the medial clavicles". 285 male patients who, for various reasons, received a chest CT at the Medical Center of the University of Freiburg between 1st December 2019 and 6th December 2022 were screened for the study, of whom 203 patients were included in the study. The stage of clavicular ossification was classified as stage 1 - 5 according to Schmeling. While 70 out of 71 patients under 21 years of age were correctly estimated to be under 21 years of age, there was one patient whose ossification on one side was classified as stage 4 and who would therefore have been estimated to be over 21 years of age. If only subjects whose ossification stage was the same on both sides are included, the specificity of the test method is 100% and the positive predictive probability is 100%. If patients for whom only one side is stage 4 are also included, the specificity is 98.6%. Thus, only the complete and symmetrical ossification of both clavicles (stage 4 according to the Schmeling classification) in a standardised thin-layer CT can be classified as a reliable indicator of an age over 21 years in young men. In the case of asymmetric ossification of the medial clavicles (stage 4 is not reached on one side), false positive evaluations and the incorrect assumption of an age over 21 years can occur.

Continual re-evaluation of standards for forensic anthropological analyses are necessary, particularly as new methods are explored or as populations change. Indian South Africans are not a new addition to the South African population; however, a paucity of skeletal material is available for analysis from medical school collections, which has resulted in a lack of information on the sexual dimorphism in the crania. For comparable data, computed tomography scans of modern Black, Coloured and White South Africans were included in addition to Indian South Africans. Four cranial morphoscopic traits, were assessed on 408 modern South Africans (equal sex and population distribution). Frequencies, Chi-squared tests, binary logistic regression and random forest modelling were used to assess the data. Males were more robust than females for all populations, while White South African males were the most robust, and Black South African females were the most gracile. Population differences were noted among most groups for at least two variables, necessitating the creation of populations-specific binary logistic regression equations. Only White and Coloured South Africans were not significantly different. Indian South Africans obtained the highest correct classifications for binary logistic regression (94.1%) and random forest modelling (95.7%) and Coloured South Africans had the lowest correct classifications (88.8% and 88.0%, respectively). This study provides a description of the patterns of sexual dimorphism in four cranial morphoscopic traits in the current South African population, as well as binary logistic regression functions for sex estimation of Black, Coloured, Indian and White South Africans.

Fingernails can act as important forensic evidence as they can be a source of DNA that may link the victim or accused to the crime scene and may also contain traces of drugs such as cocaine and heroin, in regular users. Moreover, previous studies have shown that analyzing fingernails with various techniques can reveal important information, such as age and sex. In this work, ATR-FTIR spectroscopy with chemometric tools has been used to estimate the age and sex from fingernails by analyzing 140 fingernail samples (70 males, and 70 females) collected from volunteers aged between 10 and 70 years old. The amide bands obtained from spectra confirmed the presence of keratin proteins in the samples. PCA and PLS-R were used for the classification of samples. For sex estimation, samples were divided into four categories based on age groups, followed by the differentiation of sex in each group. Similarly, for age estimation, all samples were divided into two sets based on male and female followed by differentiation of age groups in each set. The result showed that PLS-R was able to differentiate fingernail samples based on sex in groups G1, G2, G3, and G4 with R-square values of 0.972, 0.993, 0.991, and 0.996, respectively, and based on age in females, and males with R-square values of 0.93 and 0.97, respectively. External validation and blind tests were also performed which showed results with 100% accuracy. This approach has proved to be effective for the estimation of sex and age from fingernail samples.

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.

Post-mortem computed tomography (PMCT) is an increasingly utilized tool in forensic medicine for evaluating head gunshot injuries. Vault bevelling sign, when present, provides information regarding entry and exit wounds; when absent, identifying wound type on PMCT remains challenging. A cutaneous hyperdense ring, described in an animal study by Junno et al. (2022), may be indicative of contact shots. We hypothesized that it could also be observed in human gunshot injuries. Our study evaluates the reliability of the cutaneous hyperdense rim sign for identifying entry gunshot wounds in PMCT. After excluding complex and mucosal wounds, two operators retrospectively evaluated 64 gunshot wounds (30 entry and 34 exit wounds) in 34 head PMCT cases (2018-2022). Gold standard for wound type determination was the autopsy report. The hyperdense rim sign was defined as at least two-thirds of a continuous cutaneous hyperdense circle on a multiplanar reconstruction of cutaneous tissue tangent to the wound. The hyperdense rim sign demonstrated a specificity of 97% (95% CI: 85-100%) and a sensitivity of 63% (95% CI: 44-80%) for identifying entry wounds. Moreover, in 16 external examination reports where the presence of powder residues or bullet wipe at entry wound was explicitly mentioned, a positive association was observed between hyperdense rim sign and the presence of these elements (p = 0.018). These findings suggest that the hyperdense rim sign, when present, may be a valuable tool for entry wound determination in gunshot injuries, interpreted in conjunction with other CT and autopsy features.

Bone age estimation (BAE) is based on skeletal maturity and degenerative process of the skeleton. The clinical importance of BAE is in understanding the pediatric and growth-related disorders; whereas medicolegally it is important in determining criminal responsibility and establishing identification. Artificial Intelligence (AI) has been used in the field of the field of medicine and specifically in diagnostics using medical images. AI can greatly benefit the BAE techniques by decreasing the intra observer and inter observer variability as well as by reducing the analytical time. The AI techniques rely on object identification, feature extraction and segregation. Bone age assessment is the classical example where the concepts of AI such as object recognition and segregation can be used effectively. The paper describes various AI based algorithms developed for the purpose of radiologic BAE and the performances of the models. In the current paper we have also carried out qualitative analysis using Strength, Weakness, Opportunities and Challenges (SWOC) to examine critical factors that contribute to the application of AI in BAE. To best of our knowledge, the SWOC analysis is being carried out for the first time to assess the applicability of AI in BAE. Based on the SWOC analysis we have provided strategies for successful implementation of AI in BAE in forensic and medicolegal context.

Introduction: Analysis of a single tooth and nail can provide valuable forensic information, including year of birth, year of death, age, sex, DNA-profile, geographic residence during childhood and at time of death and drug exposure. The aim is to minimize the amount of used bodily material and to validate the applicability of a multidisciplinary sampling protocol.

Methods: A nail of the big toe, a tooth and blood of seven deceased individuals were collected postmortem. Collected materials were sampled and segmented in accordance with the multidisciplinary sampling protocol. DNA analysis was conducted on the pulp of the tooth, isotope analysis (Sr, Pb, O and C) on the enamel and ¹⁴C-, toxicological and tooth cementum annulation analysis on root segments. DNA-, isotope (Sr, Pb, O and C) -, toxicological-, and ¹⁴C -analysis were conducted on toenail segments. The acquired DNA profiles were compared with profiles acquired from blood.

Results: Material from seven deceased persons was analysed. 45 out of 56 analyses on dental samples were successful, constituting a success rate of 80%. Additionally, 27 out of 35 analyses were successful on nail samples, yielding a success rate of 77%. DNA-, toxicological and ¹⁴C- analyses performed better in nail than in tooth. Isotope analyses performed better in tooth than in nail. A profile with personal characteristics was constructed and matched for 62% of parameters with collected medical information.

Conclusion: The performed sampling protocol for simultaneous multidisciplinary forensic analysis on a single tooth and nail sample provided applicable results and valuable information.

Hyoid fractures are uncommon, but when they occur they are commonly the result of strangulation or hanging. Although there is a lack of available quantitative data, there is increasing evidence to suggest that strangulation is a relatively common feature of consensual sex play. This creates difficulty in clinical forensic medicine given the "rough sex" defence has previously been used successfully in cases of fatal intimate partner strangulation. We present a case where consensual and non-consensual strangulation has occurred in a woman who presents with a hyoid fracture. While manual strangulation was thought to be a more likely mechanism than consensual wearing of a sex-collar; ultimately the similar timeframes of the collar-wearing and the non-consensual manual strangulation meant that the accused was not convicted of this particular strangulation offense. This case highlights the importance of further research into consensual strangulation and the incidence of resultant injuries. It also demonstrates the importance of collecting a detailed forensic history and adequately documenting injuries in a contemporaneous matter.

To date, lipophilic contrast agents mixed with oil, usually paraffin oil, are the most commonly used contrast agents in post-mortem computed tomography angiography (PMCTA). Iodine-based hydrophilic contrast media in combination with a water-soluble carrier, e.g. polyethylene glycol (PEG), are also common. However, their influence on different tissues and organs is poorly understood. In order to analyse the changes in the cadavers caused by the different carrier substances, we evaluated the effects of PEG 200 and oil on the different tissues and organs. Therefore, during a forensic autopsy, liquid femoral vein blood and samples of different organs and vessels were taken and preserved at room temperature in the two liquids mentioned. The condition of the samples was documented during the autopsy and 24, 48 and 72 h after preservation. Microscopic examination took place after 72 h. After 24 h, the samples placed in PEG 200 already showed a clear solidification of almost all structures. Crumbly blood agglomerates had formed in the previously liquid blood. In contrast, the samples stored in oil showed signs of classic cadaveric decomposition after 24 h, which increased with time. The microscopic and immunohistochemical evaluation of the samples stored in PEG showed a good diagnostic quality. The analysis of tissues stored in oil was much more difficult due to putrefaction. PEG and oil show significantly different effects on human tissues, mainly conservation and dehydration are affected. It is crucial to be aware of these differences in order to choose the most appropriate PMCTA method for each forensic case.