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Showing 131 to 133 of 133 (0.132 seconds)Spelling suggestions: "subject:"forensic medicine"" "subject:"orensic medicine""
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Contribution à l'approche anthropologique et médico-légale des sutures viscérocrâniennes utiles dans l'estimation de l'âge au décès (Sutures palatines, fronto-naso-maxillaires et zygomatiques) / Contribution to a useful anthropological and medicolegal approach of the viscerocranial sutures for the age at death estimation (palatine, fronto-naso-maxillary and zygomatic sutures)Beauthier, Jean-Pol 30 November 2009 (has links)
Les sutures crâniennes ont été régulièrement étudiées au fil des siècles puisque déjà Vésale établissait une relation entre l’âge et la synostose suturale.<p><p>Leur imprécision a quelque peu confiné l’observation de ces sutures dans un certain oubli, justifié en partie.<p><p>Il est clair que leur fiabilité quant à l’estimation de l’âge au décès reste discutable et ce, pour diverses raisons.<p><p>Leur observation est difficile et dès lors sujette à subjectivité dans l’appréciation de leurs stades de fusion.<p><p>De plus, leur apparence sur le crâne sec peut être altérée par divers artéfacts de conservation (cire, vernis…).<p><p>Outre l’observation des classiques sutures ectocrâniennes de voûte et l’utilisation des méthodes habituelles en la matière (méthode de Acsádi et Nemeskéri, méthode de Masset), nous avons orienté notre étude vers des sutures peu voire pas exploitées, à savoir les sutures palatines, les sutures fronto-naso-maxillaires et les sutures de l’os zygomatique.<p><p>Ces trois groupes suturaux ont la particularité d’évoluer de manière très lente vers la fusion, à tel point que peu d’individus en présentent une oblitération complète.<p><p>Face au vieillissement de la population et de par notre expérience médico-légale et anthropologique d’étude de pièces osseuses de personnes âgées, nous avons estimé qu’il était utile de se pencher sur des collections particulières de sujets d’âge avancé, afin d’apprécier l’évolution morphologique de ces sutures faciales.<p><p>Si certaines personnes fort âgées gardent malgré tout des caractéristiques suturales peu évoluées, il existe dans l’ensemble, une progression suturale quasiment constante en fonction de l’âge.<p><p>Nous avons tenté de la cerner, en attribuant à ces sutures, des degrés bien définis de cette progressive fusion et par là, l’aboutissement à un coefficient moyen d’oblitération suturale, se traduisant aisément en pourcentage d’oblitération ou pouvant être introduit dans des équations de régression.<p><p>Tout en connaissant les limites de cette approche, nous pouvons estimer qu’elle peut rendre des services lors de l’étude de restes humains squelettisés, notamment s’ils appartiennent à des personnes fort âgées, dès lors qu’à ces stades de vieillissement, peu de méthodes restent encore applicables. D’autre part, l’approche en pourcentage d’oblitération suturale rend également des services lorsque les crânes étudiés sont fragmentés. C’est la situation que nous rencontrons actuellement lors de l’étude d’une très importante collection anthropologique à l’Institut royal des Sciences naturelles de Belgique.<p><p>Cette observation suturale pourra également – à l’avenir – trouver un terrain d’approche fort utile par l’étude des sutures en CT-Scan ou en micro-CT.<p><p>Enfin, grâce à ces techniques modernes d’imagerie médicale, les sutures trouvent un regain d’intérêt dans une application toute particulière, qui est celle de l’identification comparative, puisqu’il apparaît que le « dessin sutural » s’avère tout à fait propre à chaque individu.<p><p>/<p><p>Cranial sutures were regularly studied during centuries since Vésale already established a relationship between age at death and sutural fusion. <p><p>Their inaccuracy somewhat confined the observation of these joints in a certain lapse of memory, partly justified. <p><p>Various reasons clearly indicate that their reliability for age at death estimation remains debatable. <p><p>Their observation is difficult and consequently prone to subjectivity in the appreciation of their stages of fusion. <p><p>Moreover, their appearance on dry cranium can be modified by various artefacts from preserving methods (wax, varnished…). <p><p>In addition to the traditional observation of ectocranial sutures (with the usual methods such as Acsádi and Nemeskéri method and Masset method), we have directed our study towards not much exploited sutures, namely the palatine sutures, the fronto-naso-zygomatic sutures and the sutures of the zygomatic bone. <p><p>These three sutural groups are characteristic by evolving very slowly to fusion, and than, only few individuals present a complete obliteration of the latter. <p><p>Because of general population ageing and our medicolegal and anthropological experience of skeletal remains in elderly, we estimated the usefulness in studying particular collections of old people, in order to appreciate the morphological evolution of these facial joints. <p><p>Despite some very old people who present little evolved sutural characteristics, we consider as a whole, an almost constant sutural progression according to age. <p><p>We tried to define degrees of this progressive fusion and by the way, the result with a sutural obliteration average coefficient, can be easily translate as a percentage obliteration or able to be introduced into regression equations. <p><p>The limits of this approach are well known but we estimate that it is possible to help the examination of human skeletal remains in elderly, although at these stages of ageing, some methods remain still applicable. In addition, the approach expressed as a percentage of sutural obliteration is also very helpful when craniums are fragmented. This situation is currently observed on the anthropological collections at the Royal Belgian Institute of Natural Sciences. <p><p>Furthemore in the future, the sutural observation will find an interesting and useful approach by the study of the joints in CT-Scan or micro-CT. <p><p>At least, thanks to these modern techniques of medical imagery, the sutures find a renewed interest in a very particular application, such as comparative identification. It appears that the "sutural drawing" proves completely specific to each individual. <p><p> / Doctorat en sciences médicales / info:eu-repo/semantics/nonPublished
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Applied Machine Learning Predicts the Postmortem Interval from the Metabolomic FingerprintArpe, Jenny January 2024 (has links)
In forensic autopsies, accurately estimating the postmortem interval (PMI) is crucial. Traditional methods, relying on physical parameters and police data, often lack precision, particularly after approximately two days have passed since the person's death. New methods are increasingly focusing on analyzing postmortem metabolomics in biological systems, acting as a 'fingerprint' of ongoing processes influenced by internal and external molecules. By carefully analyzing these metabolomic profiles, which span a diverse range of information from events preceding death to postmortem changes, there is potential to provide more accurate estimates of the PMI. The limitation of available real human data has hindered comprehensive investigation until recently. Large-scale metabolomic data collected by the National Board of Forensic Medicine (RMV, Rättsmedicinalverket) presents a unique opportunity for predictive analysis in forensic science, enabling innovative approaches for improving PMI estimation. However, the metabolomic data appears to be large, complex, and potentially nonlinear, making it difficult to interpret. This underscores the importance of effectively employing machine learning algorithms to manage metabolomic data for the purpose of PMI predictions, the primary focus of this project. In this study, a dataset consisting of 4,866 human samples and 2,304 metabolites from the RMV was utilized to train a model capable of predicting the PMI. Random Forest (RF) and Artificial Neural Network (ANN) models were then employed for PMI prediction. Furthermore, feature selection and incorporating sex and age into the model were explored to improve the neural network's performance. This master's thesis shows that ANN consistently outperforms RF in PMI estimation, achieving an R2 of 0.68 and an MAE of 1.51 days compared to RF's R2 of 0.43 and MAE of 2.0 days across the entire PMI-interval. Additionally, feature selection indicates that only 35% of total metabolites are necessary for comparable results with maintained predictive accuracy. Furthermore, Principal Component Analysis (PCA) reveals that these informative metabolites are primarily located within a specific cluster on the first and second principal components (PC), suggesting a need for further research into the biological context of these metabolites. In conclusion, the dataset has proven valuable for predicting PMI. This indicates significant potential for employing machine learning models in PMI estimation, thereby assisting forensic pathologists in determining the time of death. Notably, the model shows promise in surpassing current methods and filling crucial gaps in the field, representing an important step towards achieving accurate PMI estimations in forensic practice. This project suggests that machine learning will play a central role in assisting with determining time since death in the future.
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Untersuchung der Geschosswirkung in der sehr frühen Phase unter besonderer Berücksichtigung der Hochgeschwindigkeitsmunition / Study of bullet effects at a very early stage with special consideration of high-speed ammunitionSiegmund, Bernward 13 November 2006 (has links)
No description available.
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