This paper presents updated recommendations of the Study Group on Forensic Age Diagnostics for age estimations in living individuals in criminal proceedings. In order to increase the diagnostic accuracy and to improve the identification of age-relevant developmental disorders, a physical examination, an X-ray examination of the left hand, as well as a dental examination including the determination of the dental status and an X-ray of the dentition should be performed in each case. If the skeletal development of the hand is completed, an additional radiological examination of the clavicles should be carried out. Minimum requirements for reference studies are defined and recommendable studies are listed. Instructions for the examination and the preparation of expert reports are presented. The committee of the study group organizes annual proficiency tests for quality assurance.
Age estimation in cadavers, human remains and living individuals may clarify issues with significant legal and social ramifications for individuals as well as for the community. In such cases methods for estimating age should fulfil the following specific demands: (1) they must have been presented to the scientific community, as a rule by publication in peer-reviewed journals, (2) clear information concerning accuracy of age estimation by the method should be available, (3) the methods need to be sufficiently accurate and (4) in cases of age estimation in living individuals principles of medical ethics and legal regulations have to be considered. We have identified and summarized the methods that essentially fulfil these specific demands. In childhood and adolescence morphological methods based on the radiological examination of dental and skeletal development are to be recommended. In adulthood, the accuracy of most morphological methods is much reduced. Here a biochemical method based on aspartic acid racemization in dentine provides the most accurate estimates of age, followed by special morphological dental and skeletal methods. The choice of method has to take account of the individual circumstances of each case. Most methods require either the consultation of specialised and trained scientists or an adequate calibration by the "user". Very few attempts have been made to find common standardisation, calibration and evaluation procedures or to develop means of quality assurance for methods of age estimation. Efforts in these directions are necessary to guarantee quality standards and adequate answers to the important legal and social issue of age estimation in forensic medicine.
The age-dependent accumulation of modified aspartic acid residues appears to be a common feature in ageing elastin, independent of the tissue source. This indicates a lack of turnover and an accumulation of elastin damage in diverse ageing tissues, possibly as part of programmed ageing.
Aging is reflected by highly reproducible DNA methylation (DNAm) changes that open new perspectives for estimation of chronological age in legal medicine. DNA can be harvested non-invasively from cells at the inside of a person's cheek using buccal swabs – but these specimens resemble heterogeneous mixtures of buccal epithelial cells and leukocytes with different epigenetic makeup. In this study, we have trained an age predictor based on three age-associated CpG sites (associated with the genes PDE4C, ASPA, and ITGA2B) for swab samples to reach a mean absolute deviation (MAD) between predicted and chronological age of 4.3 years in a training set and of 7.03 years in a validation set. Subsequently, the composition of buccal epithelial cells versus leukocytes was estimated by two additional CpGs (associated with the genes CD6 and SERPINB5). Results of this “Buccal-Cell-Signature” correlated with cell counts in cytological stains (R2 = 0.94). Combination of cell type-specific and age-associated CpGs into one multivariate model enabled age predictions with MADs of 5.09 years and 5.12 years in two independent validation sets. Our results demonstrate that the cellular composition in buccal swab samples can be determined by DNAm at two cell type-specific CpGs to improve epigenetic age predictions.
Aims: The teachers' perspectives of the educational environment have as yet only been sparsely considered. This study aimed at validating the first German version of the Dundee Ready Education Environment Measure (DREEM) from the points of view of both students and teachers. Methods: Data from 1119 students and 258 teachers were available for analysis. Psychometric validation included the analysis of homogeneity and discrimination at item level as well as reliability (Cronbach's ), criterion and construct validity at test level. Effect sizes were calculated and the independent samples t-test was used for statistical inference testing of mean differences between two groups. Results: Item characteristics were satisfactory in both samples. Reliability was high with ¼ 0.92 (students) and 0.94 (teachers), respectively. Factor analyses revealed five dimensions which slightly diverged from the five subscales postulated by the DREEM authors though. The environment was evaluated significantly ( p 5 0.001) more positively by teachers (M ¼ 117.63) than by students (M ¼ 109.75). Further significant differences were observed with regard to gender, mother language, stage of studies and previous professional training among others. Conclusions: With convincing psychometric properties at item and test levels, the suitability of DREEM not only for students but also for teachers to assess the educational environment has been demonstrated.
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