[The occurrence of contact traces of blood during medical and forensic examinations]

The purpose of the study is a theoretical analysis of the available types of contact traces of blood and the establishment of their occurrence at the objects of medical and forensic examinations. Contact marks are formed as a result of the mechanical interaction of two objects, one of which is stained with blood. The literature data allow us to distinguish several types of contact traces of blood: impressions, smears, smearing, «voids», traces in the form of changes in the existing stain from wiping, washing, traces-artifacts from insects. Each type has a mechanism of formation and characteristic features. We analyzed 107 archival medical and forensic examinations. In the examinations in which the material situation of the scene of the incident (5 or more objects) is maximally represented, contact traces were present in 76% of the examinations, which indicates a high occurrence. The following types of contact traces of blood were the most common: smears (29% of all examinations), smearing (22.4%) and «voids» (10.3%). Other types of contact traces were less common.

[Comparative assessment of technical approaches to estimating the biological age of a person using chromatographic analysis of dentin]

The study of the amino acid composition of dentin is a new approach to determining the biological age of a person in Russia. Abroad, this method is more studied, but the authors in their research use various equipment and reagents, which makes it difficult to find the optimal technical standard for implementation in domestic practice. We studied the literature over the past 5 years on age estimation by the amino acid composition of dentin. The equipment used in the work and the results obtained were compared. A comparative evaluation of the data made it possible to make an assumption about gas chromatography using mass selective or flame ionization detectors as a method of choice for studying the amino acid composition of tooth dense tissues.