Forensic Sciences Research最新文献

The occupational risk of infection in forensic workers is a cause for concern, furthermore in the current context of the coronavirus disease-19 (COVID-19) pandemic. In order to characterize this risk, we performed an extended review of the literature on occupational infections occurring in forensic workers. Seventeen articles were included. Direct contamination by aerosolization was the main mode of transmission reported, with 17 cases of tuberculosis. Indirect contamination was described as the mode of transmission in 10 cases (five cases of blastomycosis, two cases of tuberculosis, two Streptococcus pyogenes, and one case of human immunodeficiency virus). In all the other included cases, the mode of transmission was unknown. For two of them, the information provided was sufficient to link them to occupational exposure (one case of toxoplasmosis, one case of tuberculosis). For the remaining 10 cases, the link was uncertain (six cases of tuberculosis, three of hepatitis B, and one of COVID-19). Even if there is probably significant under-declaration, the number of infections linked to an occupational risk in forensic workers is not alarming, thanks to effective preventive measures.

Y-chromosome short tandem repeats (Y-STRs) have a unique role in forensic investigation. However, low-medium mutating Y-STRs cannot meet the requirements for male lineage differentiation in inbred populations, whereas rapidly mutating (RM) high-resolution Y-STRs might cause unexpected exclusion of paternal lineages. Thus, combining Y-STRs with low and high mutation rates helps to distinguish male individuals and lineages in family screening and analysis of genetic relationships. In this study, a novel 6-dye, 41-plex Y-STR panel was developed and validated, which included 17 loci from the Yfiler kit, nine RM Y-STR loci, 15 low-medium mutating Y-STR loci, and three Y-InDels. Developmental validation was performed for this panel, including size precision testing, stutter analysis, species specificity analysis, male specificity testing, sensitivity testing, concordance evaluation, polymerase chain reaction inhibitors analysis, and DNA mixture examination. The results demonstrated that the novel 41-plex Y-STR panel, developed in-house, was time efficient, accurate, and reliable. It showed good adaptability to directly amplify a variety of case-type samples. Furthermore, adding multiple Y-STR loci significantly improved the system's ability to distinguish related males, making it highly informative for forensic applications. In addition, the data obtained were compatible with the widely used Y-STR kits, facilitating the search and construction of population databases. Moreover, the addition of Y-Indels with short amplicons improves the analyses of degraded samples.

Key points: A novel multiplex comprising 41 Y-STR and 3 Y-InDel was developed for forensic application.The multiplex included rapidly mutating Y-STRs and low-medium mutating Y-STRs, which is compatible with many commonly used Y-STR kits.The multiplex is a powerful tool for distinguishing related males, familial searching, and constructing DNA databases.

Human face is a highly heritable and complex trait. Many genome-wide analyses have identified genetic variants influencing facial morphology. Genome-wide association studies (GWASs) investigating facial morphologies of different populations provide a comprehensive insight into the genetic basis of the human face. Here, we report a GWAS of normal facial variation in Koreans using an array optimized for the Korean population (KoreanChip). We found that novel genetic variants encompassing four loci reached the genome-wide significance threshold. They include LOC107984547, UBE2O, TPK1, and LINC01148 loci associated with facial angle, brow ridge protrusion, nasal height, and eyelid curvature. Our results also validated previously published genetic loci, including FAT4, SOX9, and TBX3 loci. All confirmed genetic variants showed phenotypic differences involving each facial trait based on the effect of the minor allele. The present study highlights genetic signals associated with normal human facial variation and provides candidates for functional studies.

Key points: GWAS of normal facial variation in the Korean population was conducted using a Korean genome chip.Previously reported genetic signals associated with FAT4, SOX9, and TBX3 loci were replicated in the Korean populations.Genetic signals in UBE2O and TPK1 loci were identified as novel variants for corresponding facial features.

It is important to measure scars in forensic and clinical medicine. In practice, scars are mostly manually measured, and the results are diverse and influenced by various subjective factors. With the development of digital image technology and artificial intelligence, noncontact and automatic photogrammetry has been gradually used in some practical applications. In this article, we propose an automatic method for measuring the length of linear scars based on multiview stereo and deep learning, which combines the 3D reconstruction algorithm of structure from motion and the image segmentation algorithm based on a convolutional neural network. With a few pictures taken by a smart phone, automatic segmentation and measurement of scars can be realized. The reliability of the measurement was first demonstrated through simulation experiments on five artificial scars, giving errors of length <5%. Then, experiment results on 30 clinical scar samples showed that our measurements were in high agreement with manual measurements, with an average error of 3.69%. Our study demonstrates that the application of photogrammetry in scar measurement is effective and that the deep learning technique can realize the automation of scar measurement with high accuracy.

Visual attention plays a central role in current theories of sexual information processing and is key to informing the use of eye-tracking techniques in the study of typical sexual preferences and more recently, in the study of atypical preferences such as pedophilia (prepubescent children) and hebephilia (pubescent children). The aim of this theoretical-empirical review is to connect the concepts of a visual attention-based model of sexual arousal processing with eye movements as indicators of atypical sexual interests, to substantiate the use of eye-tracking as a useful indirect measure of sexual preferences according to sex and age of the stimuli. Implications for research are discussed in terms of recognizing the value, scope and limitations of eye-tracking in the study of pedophilia and other chronophilias in males and females, and the generation of new hypotheses using this type of indirect measure of human sexual response.

The morphological changes based on deposition of secondary dentin and mineralization of the third molar have been proven to be related to chronological age. However, Kvaal's method on the theory of deposition of secondary dentin was controversial with respect to dental age estimation in the recent research. The aim of this study was to combine the parameters of Kvaal's method with relatively high correlation coefficients and mineralization stages of the third molar to improve the accuracy of predicting the dental age of subadults in northern China. A total of 340 digital orthopantomograms of subadults aged from 15 to 21 years were analysed. A training group was used to test the accuracy of the original Kvaal's method and to establish novel methods for subadults in northern China. A testing group was used to compare the accuracy of the newly established methods with the Kvaal's original method and with published method specifically used in northern China. To increase the feasibility of our estimation model, we combined the mineralization of the third molar to build a combined specific formula. The results showed that the combined specific model increased the coefficient of determination to 0.513, and the standard error of the estimate was reduced to 1.482 years. We concluded that the combined specific model based on the deposition of secondary dentin and mineralization of the third molar could improve the accuracy of dental age assessment of subadults in northern China.

Key points: The decrease in the dental pulp cavity based on deposition of secondary dentin is a useful variable for assessing age.A total of 340 orthopantomographs were used in this research, including 278 in training groups and 62 in testing groups.Original Kvaal's method underestimated the dental age for subadults in northern China.The equation of combined specific method constructed in our study was proved more suitable to calculate dental age for subadults in northern China.

Trotter and Gleser presented two sets of stature estimation equations for the US White males in their 1952 and 1958 studies. Following Trotter's suggestion favouring the 1952 equations simply due to the smaller standard errors, the 1958 equations have been seldom used and have gone without additional systematic validation tests. This study aims to assess the performance of the Trotter and Gleser 1952, Trotter and Gleser 1958, and FORDISC equations for the White males in a quantitative and systematic way, particularly when applied to the WWII and Korean War casualties. In sum, 27 equations (7 from the 1952 study, 10 from the 1958 study, and 10 from FORDISC) were applied to the osteometric data of 240 accounted-for White male casualties of the WWII and Korean War. Then, the bias, accuracy, and Bayes factor for each set of stature estimates were calculated. The results show that, overall, Trotter and Gleser's 1958 equations outperform the 1952 and FORDISC equations in terms of all three measures. Particularly, the equations with higher Bayes factors produced stature estimates where distributions were closer to that of the reported statures than those with lower Bayes factors. When considering Bayes factors, the best performing equation was the "Radius" equation from the 1958 study (BF = 15.34) followed by the "Humerus+Radius" equation from FORDISC (BF = 14.42) and the "Fibula" equation from the 1958 study (BF = 13.82). The results of this study will provide researchers and practitioners applying the Trotter and Gleser stature estimation method with a practical guide for equation selection.

Key points: The performance of three stature estimation methods was compared quantitatively.Trotter and Gleser's (1952, 1958) and FORDISC White male equations were included.Overall, Trotter and Gleser's 1958 method outperformed the other methods.This study provides a practical guide for stature estimation equation selection.

Wound age estimation is one of the most challenging and indispensable issues for forensic pathologists. Although many methods based on physical findings and biochemical tests can be used to estimate wound age, an objective and reliable method for inferring the time interval after injury remains difficult. In the present study, endogenous metabolites of contused skeletal muscle were investigated to estimate the time interval after injury. Animal model of skeletal muscle injury was established using Sprague-Dawley rat, and the contused muscles were sampled at 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, and 48 h postcontusion (n = 9). Then, the samples were analysed using ultraperformance liquid chromatography coupled with high-resolution mass spectrometry. A total of 43 differential metabolites in contused muscle were determined by metabolomics method. They were applied to construct a two-level tandem prediction model for wound age estimation based on multilayer perceptron algorithm. As a result, all muscle samples were eventually divided into the following subgroups: 4, 8, 12, 16-20, 24-32, 36-40, and 44-48 h. The tandem model exhibited a robust performance and achieved a prediction accuracy of 92.6%, which was much higher than that of the single model. In summary, the multilayer perceptron-multilayer perceptron tandem machine-learning model based on metabolomics data can be used as a novel strategy for wound age estimation in future forensic casework.

Key points: The changes of metabolite profile were correlated with the time interval after injury in contused skeletal muscle.A panel of 43 endogenous metabolites screened by ultraperformance liquid chromatography coupled with high-resolution mass spectrometry could distinguish the wound ages.The multilayer perceptron (MLP) algorithm exhibited a robust performance in wound age estimation using metabolites.The combination of matabolomics and MLP-MLP tandem model could improve the accuracy of inferring the time interval after injury.