[Immunochromatographic analysis of determination of narcotic substances using test systems containing gold nanoparticles, on the example of morphine and amphetamine].

Currently, there is a constant expansion of the range of narcotic substances that differ from each other by a small structural fragment. The option of determining narcotic substances using test panels is widespread due to its rapidity and high specificity through the use of immunochemical reactions. The purpose of the study was to optimize the determination of morphine and amphetamine in bioobjects (synthetic and natural urine) using immunochromatographic analysis with new test panels and to select the optimal conditions for mass analysis.

Quantitative phase imaging of living cells: application of the phase volume and area functions to the analysis of "nucleolar stress".

We applied coherent phase microscopy to develop a method of quantitative evaluation of functional state of eukaryotic cells using the coordinates of characteristic points (CP) in the functions of the phase volume W and area S. In a fragment of a single cell image (HCT116 human colon carcinoma cell line) with detectable nucleolus, the values of the phase thickness, area, and volume were calculated. These values dramatically changed within the initial minutes of cell exposure to the transcriptional inhibitor actinomycin D.

Dissecting eukaryotic cells by coherent phase microscopy: quantitative analysis of quiescent and activated T lymphocytes.

We present a concept for quantitative characterization of a functional state of an individual eukaryotic cell based on interference imaging. The informative parameters of the phase images of quiescent and mitogen-activated T lymphocytes included the phase thickness, phase volume, the area, and the size of organelles. These parameters were obtained without a special hypothesis about cell structure.

Quantitative real-time analysis of nucleolar stress by coherent phase microscopy.

We develop a method of coherent phase microscopy (CPM) for direct visualization of nonfixed, nonstained mammalian cells (both cultured cells and freshly isolated tumor biopsies) followed by computer-assisted data analysis. The major purpose of CPM is to evaluate the refractive properties of optically dense intracellular structures such as the nucleus and the nucleoli. In particular, we focus on quantitative real-time analysis of the nucleolar dynamics using phase thickness as an equivalent of optical path difference for optically nonhomogenous biological objects.

Observation of a near-surface structural phase transition in SrTiO3 by optical second harmonic generation.

A near-surface structural phase transition on a SrTiO3 single crystal, occurring at T(*) about 45 K above the bulk cubic-to-tetragonal transition, is observed by means of optical second harmonic generation. The temperature dependence of the second harmonic field in the vicinity of T(*) is described with a phenomenological Landau-type model.

Propagation of curved activation fronts in anisotropic excitable media.

We study theoretical and numerical propagation of autowave fronts in excitable two-variable (activator-inhibitor) systems with anisotropic diffusion. A general curvature-velocity relation is derived for the case that the inhibitor diffusion is neglected. This relation predicts the break of an activation front when the front curvature exceeds a critical value, which is corroborated by computer simulations of a particular reaction-diffusion model.