Forensic science international最新文献

Background

Post-mortem toxicology constantly deals with the research of reliable alternative matrices to be applied in case of highly damaged corpses (such us carbonized, skeletonized, human remains, etc.). Teeth represent a promising alternative matrix since dental tissues are endowed by different features, resistance and stability after death.

Scope

Since scant literature reported on the pharmacokinetics and mechanism of incorporation of xenobiotics into dental tissues, this pilot research aims to investigate whether in the pulp can be detected the same substances found in blood in drug related death cases. Secondly, the study is addressed to disclose the possible deposit of drugs in dental hard tissues (dentine and/or enamel), thus contributing to reconstruct the drug abuse history (timing, e.g.).

Materials and methods

The study experimented with a novel method to separately analyse dental enamel, dentin, and pulp, applied to 10 teeth collected during autopsies of drug-related deaths along with blood and hair samples for classic toxicological analyses. Each tooth was prepared by “pulverization technique” and then analysed by gas chromatography paired with mass spectrometry (GC-MS) and ultra high performance liquid chromatography coupled to high resolution mass spectrometry (UHPLC/HR-MS) for searching cocaine, opiates, and metabolites. The results were then compared with those obtained from blood and hair samples.

Results

Preliminary results demonstrated that teeth differ from any other classic matrix (blood and hairs) since the qualitative correspondence of the detected substances between pulp and blood as well as dental hard tissues and hair suggests that they can be useful in post-mortem evaluation as a unique matrix for both acute and chronic assumptions of drugs. The mechanism of accumulation of substances in mineralized dental tissues emerged the most significant result, being influenced by the type of molecule and the method of assumption. The main limitation of this study is the limited availability of the sample and the absence of anamnestic information of the time, rates and method of drug assumption during life. Further research is necessary to systematically investigate the distribution of different substances within the different tissues of the tooth.

Aim

The aim of the present study was to investigate the relationship between blood concentrations of four different drug classes; ethanol, benzodiazepines, amphetamines and tetrahydrocannabinol (THC) and driver impairment as assessed by a clinical test of impairment (CTI).

Methods

Data was retrieved from a national database on CTI assessments and accompanying blood drug concentrations from apprehended drivers. All drug concentrations in blood were quantified using Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS), and compared to the results of the CTI which were categorized as either “not impaired”, “mildly impaired”, “moderately impaired”, or “considerably impaired”.

Results

A total number of 15 514 individual mono drug-cases collected over 9 years was included. 89 % were men and the median age was 34 years. In addition, 3 684 individual cases with similar age and gender distribution where no drugs were detected, were included as a reference group. For ethanol and benzodiazepines the percentage of clinically impaired cases increased markedly from lower to higher concentration windows, from 60 % to 97 % for ethanol and from 38 % to 76 % for benzodiazepines. The corresponding increase for amphetamines and THC was modest, from 43 % to 58 % for amphetamines and from 41 % to 55 % for THC. The correlation between drug concentration and degree of impairment was high for ethanol (Spearman´s rho=0.548, p<0.001) and relatively high for benzodiazepines (Spearman´s rho=0.377, p<0.001), but low for amphetamines (Spearman´s rho=0.078, p<0.001) and THC (Spearman´s rho=0.100, p<0.001).

Conclusion

The percentage of impaired drivers increased with increasing blood drug concentration for all four drug classes, most pronounced for ethanol and benzodiazepines and much less for amphetamines and THC. The median blood drug concentration increased with increasing magnitude of impairment for ethanol and benzodiazepines, while this was much less pronounced for amphetamines and THC. The ranges of drug concentrations, however, were wide for all four drug classes in all impairment categories as assessed by individual clinical examination.

The petrous bone contains significantly higher amounts of DNA than any other human bone. Because of highly destructive sampling and because it is not always part of the recovered remains, the need for alternative sources of DNA is important. To identify additional optimal bone types, petrous bones were compared to femurs, tali, and calcanei sampled from 66 adult skeletons from two distinct modern-era Christian cemeteries. An extraction method employing full demineralization was used to obtain DNA, real-time PCR quantification to ascertain DNA quantity and degradation, and a commercial forensic short tandem repeats (STR) PCR amplification kit to determine genetic profiles. Statistical analysis was performed to explore the differences in DNA yield, DNA degradation, and success of STR amplification. A systematic studies exploring intra-skeletal variability in DNA preservation including various excavation sites differing by time period and geographical position are rare, and the second part of the investigation was based on a comparison of both archaeological sites, which allowed us to compare the effect of different post-mortem intervals and environmental conditions on DNA preservation. The older burial site in Črnomelj was active between the 13th and 18th century, whereas the more recent Polje burial was in use from the 16th to 19th century, creating different temporal and geographical environments. Results for the Črnomelj burial site revealed that the petrous bone outperformed all other bone types studied, except the calcaneus. At the Polje archeological site calcanei, tali, and femurs yielded the same STR typing success as petrous bones. The results obtained highlight the importance of careful bone sample selection for DNA analysis of aged skeletal remains. In addition to petrous bones, calcanei were found to be an alternative source of DNA when older burial sites are investigated. When more recent burial sites are processed, calcanei, tali, and femurs should be sampled besides petrous bones, not only because they exhibited good performance, but also because of easier sampling and easier grinding in the case of trabecular bones. This study contributes valuable insights into the potential use of various skeletal types as a source of DNA for investigation of aged skeletal remains, and it offers practical implications for forensic and archaeological investigations.

The development of 3D printing technology has brought new risks and challenges to stamp impression identification. To prevent potential risks, a total of 45 stamps were printed using three types of 3D printers: fused deposition molding (FDM) printer, stereo lithography (SLA) printer, and liquid crystal display (LCD)-based SLA 3D printer, including 6 stamps replicated using LCD-based SLA 3D printer. A preliminary study was conducted on the printed stamps and stamped impressions, and the results showed that stamp are influenced by various factors such as printer type, printing material, the technology level of the producer, mold parameters such as font, size, printing parameters, slicing direction, and polishing process, etc., resulting in significant differences in characteristics. However, there are some obviously common characteristics such as missing of strokes, exposure of white and mottled phenomenon in the impression stamped by the 3D produced stamp. The impression of stamp replicated with an LCD 3D printer can be easily identified since it is difficult to achieve consistency with the real impression in detail characteristics.

Chrysomya rufifacies (Diptera: Calliphoridae) is a blow fly species of forensic importance, documented to have a strong preference for colonisation of substrate already inhabited by heterospecific blow fly larvae, thus exhibiting secondary colonisation behaviour. Larvae exhibit predatory behaviour that may be useful to support development where food substrate is limited or high competition exists, but they may alternately be drawn to pre-colonised substrate to capitalise on the advantages of collective exodigestion by previous/current colonisers. Previous authors have suggested female Ch. rufifacies may use visual orientation to detect substrate currently colonised by heterospecific larvae, rather than chemoreception of volatile organic compounds (VOCs), that signify condition of substrate, which would infer that active colonisation is likely a more important oviposition cue for Ch. rufifacies than substrate condition. This study addressed attraction as well as oviposition, examining whether the condition of substrate (either previously colonised or never colonised) or the presence of heterospecific larvae was more important in the initial choice of food source by female Ch. rufifacies where conspecifics were not present, and whether the condition of substrate and presence of heterospecific larvae affects the number of offspring deposited by a female. Attraction was studied using a Y-olfactometer system, and oviposition using a binary-choice assay, with females responding to pairwise choice between an array of meat conditions (fresh, larval aged or aged) and presence/absence of Lucilia sericata larvae. Females displayed a hierarchy of choice of larval aged substrate > aged substrate > fresh substrate, with the active presence of heterospecific larvae a secondary factor in choice. Females produced higher offspring numbers on meat that was either currently or previously colonised by heterospecific larvae, demonstrating the importance of heterospecific indicators of previous or current colonisation as an oviposition cue. This serves as an important consideration for entomologists working with Ch. rufifacies in any capacity where other blow fly species may be present, and most importantly for forensic entomologists where time of colonisation is utilised to estimate PMI.

Stature estimation is a core component to the biological profile in forensic anthropology casework. Here we provide mathematical equations for estimating stature for contemporary American Indians (AI), which currently are lacking in forensic anthropology. Drawing on postmortem computed tomography data from the New Mexico Decedent Image Database we regressed cadaveric length on four long bone length measures of the tibia, femur, and humerus to produce 11 combinations of models. Separate regression models were calculated for the entire pooled sample, by sex, broad AI language groups, and age + sex subsamples and compared. Sex-specific models were statistically better than general models, which were more accurate than language group and age + sex models. Equations were created for general and sex-specific models. Application to an independent test sample demonstrates the equations are accurate for stature estimation with overestimates of less than 1 cm. The equations provide similar levels of precision to stature estimation programs like the FORDISC 3.0 module and other stature equations in the literature. We provide recommendations for equation use in casework based on our results. These equations are the first for estimating stature in contemporary AI. This paper demonstrates the appropriateness of these newly created stature equations for use in New Mexico and the surrounding region.

Dental measurements have been proposed as parameters for stature estimation for at least 85 years. The scientific literature on the topic, however, is controversial regarding the performance of the method. This systematic literature review of observational cross-sectional studies aimed to compile evidence to support decisions in the forensic practice regarding the use of dental measurements for stature estimation. Embase, LILACS, MedLine (via PubMed), SciELO, Scopus, Web of Science, DansEasy and Open Access Thesis and Dissertations (OATD) were searched. Data regarding the rate of correct stature classifications were extracted. A meta-analysis with a Random Intercept Logistic Regression model and a Logit Transformation was conducted. The search led to 10.803 entries, out of which 15 were considered eligible (n = 1486 individuals). The studies were published between 1990 and 2020 and were authored by South American (n = 7) and Asian (n = 8) research teams. Dental measurements were predominantly (93.34 %) performed on dental casts or via intraoral inspection. The overall rate of correct classifications based on stature was 68 %. Excluding outliers, the overall accuracy of the method decreased to 64 % (95 %CI: 54–73 %). Significant heterogeneity was detected (I² = 72.4 %, τ2 = 0.24, H = 1.91, p < 0.001). Egger's test (p = 0.94) and the funnel plot did not reveal publication bias. Dental measurements are not reliable for stature estimation in the forensic field.

The inception of forensic DNA elimination database represents a pivotal advancement in forensic science, aiming to streamline the process of distinguishing between DNA found at crime scenes and that of individuals involved in the investigation process, such as law enforcement personnel and forensic lab staff. In subsequent phases, once familiarity with the database is achieved by its administrators and other stakeholders, and they have accrued sufficient experience, the possibility of expanding the database to encompass first responders—including firefighters, paramedics, emergency medical technicians, and other emergency services personnel—can be contemplated. Key challenges in managing these databases encompass the grounds for collecting samples, ensuring the integrity of both samples and profiles, along with the duration of retention, access to the database, and the protocols to follow when a match is found in the database. This paper outlines the conceptual and detailed legislative framework in Hungary, where the forensic DNA elimination database was introduced in 2022.

When a disaster occurs, the authority must prioritise two things. First, the search and rescue of lives, and second, the identification and management of deceased individuals. However, with thousands of dead bodies to be individually identified in mass disasters, forensic teams face challenges such as long working hours resulting in a delayed identification process and a public health concern caused by the decomposition of the body. Using dental panoramic imaging, teeth have been used in forensics as a physical marker to estimate the age of an individual. Traditionally, dental age estimation has been performed manually by experts. Although the procedure is fairly simple, the large number of victims and the limited amount of time available to complete the assessment during large-scale disasters make forensic work even more challenging. The emergence of artificial intelligence (AI) in the fields of medicine and dentistry has led to the suggestion of automating the current process as an alternative to the conventional method. This study aims to test the accuracy and performance of the developed deep convolutional neural network system for age estimation in large, out-of-sample Malaysian children dataset using digital dental panoramic imaging. Forensic Dental Estimation Lab (F-DentEst Lab) is a computer application developed to perform the dental age estimation digitally. The introduction of this system is to improve the conventional method of age estimation that significantly increase the efficiency of the age estimation process based on the AI approach. A total number of one-thousand-eight-hundred-and-ninety-two digital dental panoramic images were retrospectively collected to test the F-DentEst Lab. Data training, validation, and testing have been conducted in the early stage of the development of F-DentEst Lab, where the allocation involved 80 % training and the remaining 20 % for testing. The methodology was comprised of four major steps: image preprocessing, which adheres to the inclusion criteria for panoramic dental imaging, segmentation, and classification of mandibular premolars using the Dynamic Programming-Active Contour (DP-AC) method and Deep Convolutional Neural Network (DCNN), respectively, and statistical analysis. The suggested DCNN approach underestimated chronological age with a small ME of 0.03 and 0.05 for females and males, respectively.

The use of protein stains to enhance fingermark ridge detail in blood is a common technique used by forensic practitioners around the world. Amido Black is one of the most favoured protein stains due to its strong staining ability. The most common formulation of Amido Black is methanol based, with an ability to simultaneously fix and stain the blood impression, however methanol is toxic and can disrupt some surfaces, potentially compromising fingermark detail. If the surface is suspected of being a material that is impacted by methanol, there is an alternative aqueous formulation, which requires a fixative step to set the blood prior to staining so as not to wash away potential ridge detail. The multi-step process of aqueous protein stains is tedious and numerous studies have been conducted to improve the formula to achieve a combined fixing/staining solution that performs like the methanolic reagent. A combined fixative and stain formulation of aqueous based Amido Black was compared to a multi-step formulation with a separate sulfosalicylic acid fixative. Of the 243 split fingermark impressions analysed the majority (63.5 %) showed no preference to either treatment, with a marginally greater proportion of the remaining marks slightly favouring the combined fixative and stain formulation. Given that the new combined formulation performed broadly similarly to the existing multi step formulation, the potential time savings of this simpler approach may be beneficial to implement into operational use.