[Capabilities of using a multifunctional led device in the study of objects of forensic examination]

The purpose of the work is to determine the capabilities of the modern multifunctional device «Photobox 3138» with LED illuminators with a high color rendering index for photofixation, colorimetric, spectrozonal and multispectral analyzes of forensic objects. The competencies of the «Photobox 3138» device were experimentally revealed in terms of visualization and photofixation of both traces of biological origin (blood, sweat fat, saliva, etc.) and traces of traditional examinations, including shot products, oil products. The design of the device with a working field of 300×300 mm provides for the optimal arrangement of LED illuminators, including white light with a high color rendering index; spectrum-zonal illuminator with 4 types of LEDs with narrow non-intersecting spectral lines (458.1; 523.1; 594.1 and 630.6 nm) in the visible range of the spectrum; UV- (370 nm) and IR- (850 nm) illuminators. The fundamental possibility of using the resulting digital images of forensic objects for subsequent mathematical processing is experimentally shown. Images taken in different spectral ranges help to detect traces and damage. It was found that «Photobox 3138» allows you to solve a variety of diagnostic tasks related to the search, visualization, fixation and analysis of trace information.

Computer Vision in Analyzing the Propagation of a Gas-Gunpowder Jet

A method of mathematically processing the digital images of targets is developed. The theoretical and mathematical justification and the experimental validation of the possibility of estimating the amount of gunshot residue (GSR) and determining the GSR distribution over the target on the basis of its digital image is provided. The analysis of the optical density in selected concentric rings in the images reveals the radial dependence of soot distribution in the cross section of a gas-gunpowder jet. The analysis of the optical density in selected sectors of the circle reveals the angular dependence of the soot distribution in the gas-gunpowder jet cross section. It is shown that the integral optical density averaged over a selected area in the target image characterizes the mass of GSP deposited on it. It is possible to quantify the differences in the radial and angular distributions of the thickness of the GSR layer on various targets obtained both with the help of weapons of different types at the same distances and with the help of weapons of the same type at different distances, by calculating the distribution of optical density on their digital images.

Mitochondrial Antioxidant SkQ1 Improves Hypothermic Preservation of the Cornea

Diseases of the cornea are a frequent cause of blindness worldwide. Keratoplasty is an efficient method for treating severely damaged cornea. The functional competence of corneal endothelial cells is crucial for successful grafting, which requires improving the media for the hypothermic cornea preservation, as well as developing the methods for the evaluation of the corneal functional properties. The transport of water and ions by the corneal endothelium is important for the viability and optic properties of the cornea. We studied the impact of SkQ1 on the equilibrium sodium concentration in the endothelial cells after hypothermic preservation of pig cornea at 4°C for 1, 5, and 10 days in standard Eusol-C solution. The intracellular sodium concentration in the endothelial cells was assayed using the fluorescent dye Sodium Green; the images were analyzed with the custom-designed CytoDynamics computer program. The concentrations of sodium in the pig corneal endothelium significantly increased after 10 days of hypothermic preservation, while addition of 1.0 nM SkQ1 to the preservation medium decreased the equilibrium concentration of intracellular sodium (at 37°C). After 10 days of hypothermic preservation, the permeability of the plasma membrane for sodium decreased in the control cells, but not in the cells preserved in the presence of 1 nM SkQ1. Therefore, SkQ1 increased the ability of endothelial cells to restore the intracellular sodium concentration, which makes SkQ1 a promising agent for facilitating retention of the functional competence of endothelial cells during cold preservation.

Quantization noise as a determinant for color thresholds in machine vision

Color discrimination simulation is applied to study a uniformity of the color space of machine vision devices whose operation is based on a three-component color model and which involve analog-to-digital conversion of signals with a resolution of 8 bits per channel. Algorithms for finding the intervals of the dominant wavelength and color saturation of a specimen are developed. The spectral dependence of intervals of color parameters calculated using the digital images is found. It is shown that machine vision possesses the color discrimination thresholds, which can be drawn in the CIE1931 xy chromaticity diagram in the form of equal-contrast ellipses similar to the MacAdam ellipses. At resolution of 6 bits, the size of a reference MacAdam's ellipse is a little less than that of the machine vision ellipse's sizes, and at resolution of 7 bits, it is a little more than that of the machine vision ellipse's sizes. A hypothesis is proposed that implies that the process of an encoding of the visual neural signals may include procedures similar to an analog-to-digital conversion.

Novel Polarizing Method for Light Microscopy

A test of the qualities of polarizing filters was performed for a set of specimens including a bulk Nicol prism, standard polaroids, and special polyvinyl alcohol (PVA)-iodine thin-film filters coated on both sides by vertically oriented carbon nanotubes. The residual transmission of polarizing filters depending on the incidence angle of polarized light was examined in detail. The superior quality of polarizing film filters treated with carbon nanotubes was found. This fact allows us to propose a new application for polarizing films with carbon nanotubes for a polarizing cover glass. In such a way the cover glass may serve as an analyzer in a light polarizing microscope. Some features of optical scheme arrangement for the polarizing technique are discussed. The polarizing cover glass allows elimination of depolarization of light, which is inserted in a microscope objective. Test results of the proposed polarizing technique attest to the efficiency of using the polarizing cover glass. The new scheme for polaroid arrangement shows image-contrast enhancement by several percent in comparison with the standard layout.