Browsing by Author "Cunha, E"
Now showing 1 - 10 of 22
Results Per Page
Sort Options
- Adult skeletal age-at-death estimation through deep random neural networks: a new method and its computational analysisPublication . Navega, D; Costa, Ernesto; Cunha, EAge-at-death assessment is a crucial step in the identification process of skeletal human remains. Nonetheless, in adult individuals this task is particularly difficult to achieve with reasonable accuracy due to high variability in the senescence processes. To improve the accuracy of age-at-estimation, in this work we propose a new method based on a multifactorial macroscopic analysis and deep random neural network models. A sample of 500 identified skeletons was used to establish a reference dataset (age-at-death: 19–101 years old, 250 males and 250 females). A total of 64 skeletal traits are covered in the proposed macroscopic technique. Age-at-death estimation is tackled from a function approximation perspective and a regression approach is used to infer both point and prediction interval estimates. Based on cross-validation and computational experiments, our results demonstrate that age estimation from skeletal remains can be accurately (~6 years mean absolute error) inferred across the entire adult age span and informative estimates and prediction intervals can be obtained for the elderly population. A novel software tool, DRNNAGE, was made available to the community
- Aplicações Forenses da Impressão em 3DPublication . Marques, J; Durão, C; Miamoto, P; Oliveira, J; Cunha, E
- Automated age‐at‐death estimation by cementochronology: Essential application or additional complication?Publication . Bertrand, Benoit; Vercauteren, Martine; Cunha, E; Bécart, Anne; Gosset, Didier; Hédouin, ValeryIt has been repeatedly acknowledged that age-at-death estimation based on dentalcementum represents a partial and time-consuming method that hinders adoptionof this histological approach. User-friendly micrograph analysis represents a grow-ing request of cementochronology. This article evaluates the feasibility of using amodule to accurately quantify cementum deposits and compares the module's per-formance to that of a human expert. On a dental collection (n=200) of known-ageindividuals, precision and accuracy of estimates performed by a developed pro-gram (101 count/tooth;n=20,200 counts) were compared to counts performedmanually (5 counts/tooth;n=975 counts). Reliability of the software and agree-ment between the two approaches were assessed byintraclass correlation coeffi-cient and Bland Altman analysis. The automated module produced reliable andreproducible counts with a higher global precision than the human expert. Althoughthe software is slightly more precise, it shows higher sensitivity to taphonomic dam-ages and does not avoid the trajectory effect described for age-at-death estimationin adults. Likewise, for human counts, global accuracy is acceptable, but underestima-tions increase with age. The quantification of the agreement between the twoapproaches shows a minor bias, and 94% of individuals fall within the intervals ofagreement. Automation gives an impression of objectivity even though the region ofinterest, profile position and parameters are defined manually. The automated systemmay represent a time-saving module that can allow an increase in sample size, whichis particularly stimulating for population-based studies.
- Avaliação da eficácia da lise diferencial em amostras biológicas de processos sexuaisPublication . Vieira Da Silva, Cláudia; Sampaio, Lisa; Cunha, E; Corte Real, F.; Carvalho, MónicaEm todos os processos de genética forense, o objetivo consiste na obtenção de um perfil genético identificativo de um ou vários indivíduos intervenientes num determinado processo. Nos casos de abuso sexual, em particular, são recolhidos vestígios biológicos constituídos por sangue, sémen, saliva, células epiteliais entre outros. Acresce ainda nestes casos, que, muitas amostras biológicas, são frequentemente constituídas por misturas muito desproporcionais de material celular das vítimas e dos supostos agressores. A maior concentração de material genético feminino relativamente à concentração de material genético masculino, pode impedir a obtenção de um perfil genético autossómico masculino ou mesmo de mistura. Nestes casos, a identificação do agressor só poderá ser efetuada recorrendo aos marcadores do cromossoma Y, que apenas identifica a linhagem paterna. Outra abordagem para estas situações seria a utilização da extração diferencial, que em algumas condições permite a obtenção de um perfil genético masculino autossómico. Com o objetivo de avaliar uma metodologia recente de extração diferencial em amostras forenses, foram selecionadas, com base nos resultados de quantificação de ADN, 10 amostras recolhidas em processos de agressão sexual. Estas amostras, foram previamente estudadas com os métodos de extração PrepFiler Express™ (Applied Biosystems) e quantificação de ADN com o método Quantifiler™ Trio DNA Quantification Kit (Applied Biosystems). Estes métodos revelaram a presença de uma mistura de material masculino e feminino com proporções de 1:10, respetivamente. O ADN de uma segunda porção destas amostras foi extraído pelo método Sampletype-i-sep® DL (Biotype), que permite a separação de ADN em misturas de material biológico de uma forma simples e com pouca manipulação das amostras, minimizando o erro e a contaminação das mesmas. A avaliação da eficácia do método de extração diferencial foi efetuada recorrendo à determinação da concentração de ADN e à amplificação de marcadores autossómicos e do cromossoma Y. Os dois métodos de extração foram comparados entre si de forma a verificar qual o método que permitiu a obtenção do perfil genético mais discriminativo. A análise dos resultados revelou que este método constituir uma mais valia importante na resolução dos casos de agressão sexual. Assim, um passo importante para a abordagem dos processos de agressão sexual, pode consistir na aplicação de métodos de separação das células espermáticas masculinas das células epiteliais femininas designado por lise diferencial, nomeadamente o método Sampletype-i-sep® DL
- A Blood–bone–tooth model for age prediction in forensic contextsPublication . Correia Dias, Helena; Manco, Licínio; Corte Real, F.; Cunha, EThe development of age prediction models (APMs) focusing on DNA methylation (DNAm) levels has revolutionized the forensic age estimation field. Meanwhile, the predictive ability of multi-tissue models with similar high accuracy needs to be explored. This study aimed to build multi-tissue APMs combining blood, bones and tooth samples, herein named blood–bone–tooth-APM (BBT-APM), using two different methodologies. A total of 185 and 168 bisulfite-converted DNA samples previously addressed by Sanger sequencing and SNaPshot methodologies, respectively, were considered for this study. The relationship between DNAm and age was assessed using simple and multiple linear regression models. Through the Sanger sequencing methodology, we built a BBT-APM with seven CpGs in genes ELOVL2, EDARADD, PDE4C, FHL2 and C1orf132, allowing us to obtain a Mean Absolute Deviation (MAD) between chronological and predicted ages of 6.06 years, explaining 87.8% of the variation in age. Using the SNaPshot assay, we developed a BBT-APM with three CpGs at ELOVL2, KLF14 and C1orf132 genes with a MAD of 6.49 years, explaining 84.7% of the variation in age. Our results showed the usefulness of DNAm age in forensic contexts and brought new insights into the development of multi-tissue APMs applied to blood, bone and teeth
- Challenges and (Un)Certainties for DNAm Age Estimation in FuturePublication . Correia Dias, Helena; Cunha, E; Corte Real, F.; Manco, LicínioAge estimation is a paramount issue in criminal, anthropological, and forensic research. Because of this, several areas of research have focused on the establishment of new approaches for age prediction, including bimolecular and anthropological methods. In recent years, DNA methylation (DNAm) has arisen as one of the hottest topics in the field. Many studies have developed age- prediction models (APMs) based on evaluation of DNAm levels of many genes in different tissue types and using different methodological approaches. However, several challenges and confounder factors should be considered before using methylation levels for age estimation in forensic contexts. To provide in-depth knowledge about DNAm age estimation (DNAm age) and to understand why it is not yet a current tool in forensic laboratories, this review encompasses the literature for the most relevant scientific works published from 2015 to 2021 to address the challenges and future directions in the field. More than 60 papers were considered focusing essentially on studies that developed models for age prediction in several sample types
- Enlarged parietal foramina: a rare forensic autopsy findingPublication . Durão, C; Carpinteiro, D; Pedrosa, F; Machado, MP; Cunha, EEnlarged parietal foramina (EPF) are a quite rare developmental defect of the parietal bone which has to be distinguished from the normal small parietal foramina. We report a forensic case of an individual found in an advanced state of putrefaction in his own house with an undetermined cause of death. No evidence of trauma was observed, and the toxicological exam was negative. The victim was a 40-year-old man with a history of epilepsy. The large biparietal foramina, a rare anatomical variation and unusual autopsy finding, were observed at autopsy. The recognition of anatomical variations is important to avoid false interpretations and conclusions and has a significant potential as an identity factor, thus contributing to positive identification.
- Evaluation of ancestry from human skeletal remains: a concise reviewPublication . Cunha, E; Ubelaker, Douglas H.Ancestry assessment represents a major component of forensic anthropological analysis of recovered human remains. Interpretations of ancestry, together with other aspects of the biological profile, can help narrow the search of missing persons and contribute to eventual positive identification. Such information can prove useful to authorities involved in the identification and investigative process since many lists of missing persons have a reference to this parameter. Recent research has strengthened available methodologies involving metric, non-metric morphological as well as chemical and genetic approaches. This review addresses the new anthropological techniques that are now available, as well as the complex historical context related to ancestry evaluation.
- Evaluation of data collection bias of third molar stages of mineralisation for age estimation in the livingPublication . de Oliveira Santos, Inês; Baptista, Isabel Poiares; da Silva, Ricardo Henrique Alves; Cunha, EAge assessment of the living is a fundamental procedure in the process of human identification, in order to guarantee fair treatment of individuals, which has ethical, civil, legal, and medical repercussions. The careful selection of the appropriate methods requires evaluation of several parameters: accuracy, precision of the method, as well as its reproducibility. The approach proposed by Mincer et al. adapted from Demirjian et al. exploring third molar mineralisation, is one of the most frequently considered for age estimation of the living. Thus, this work aims to assess potential bias in the data collection when applying the classification stages for dental mineralisation adapted by Mincer et al. A total of 102 orthopantomographs, of clinical origin, belonging to individuals aged between 12 and 25 years ( = 20.12 years, SD = 3.49 years; 65 females, 37 males, all of Portuguese nationality) were included and a retrospective analysis performed by five observers with different levels of experience (high, average, and basic). The performance and agreement between five observers were evaluated using Weighted Cohen’s Kappa and the Intraclass Correlation Coefficient. To access the influence of impaction on third molar classification, variables were tested using ordinal logistic regression Generalised Linear Model. It was observed that there were variations in the number of teeth identified among the observers, but the agreement levels ranged from moderate to substantial (0.4–0.8). Upon closer examination of the results, it was observed that although there were discernible differences between highly experienced observers and those with less experience, the gap was not as significant as initially hypothesised, and a greater disparity between the classifications of the upper (0.24–0.49) and lower third molars (>0.55) was observed. When bone superimposition is present, the classification process is not significantly influenced; however, variation in teeth angulation affects the assessment. The results suggest that with an efficient preparation, the level of experience as a factor can be overcome. Mincer and colleague's classification system can be replicated with ease and consistency, even though the classification of upper and lower third molars presents distinct challenges.
- «
- 1 (current)
- 2
- 3
- »