Investigation of boundary-value problem for stationary system of equations of viscous non-isothermal fluid

In the Stokes approximation at small Reynolds and Peclet numbers, we obtain a solution to the boundary-value problem of flow around of particles of spherical shape for stationary system of equations of a viscous non-isothermal fluid comprising a linearized by speed Navier-Stokes equation system and the equation of heat transfer given an exponential-power law of dependence of viscosity of fluid on temperatur

Liposomal forms of new antitumor drugs based on europium chelates examined by P-terphenyl fluorescence quenching

Europium chelates have been previously shown to possess pronounced cytotoxic activity. These compounds are of great interest for biomedical investigations and diagnostics, because their spectral characteristics are optimal for visualization of the occurred processes. Application of these pharmaceutical compounds in the free form is limited by their high toxicity and metabolic instability. In view of this, the development of the delivery systems for europium chelates becomes actual. Liposomes represent one of the most promising delivery systems, which allows to increase the efficiency of pharmacological agents. The use of liposomal formulations of antitumor drugs is currently in a focus of biomedical and biophysical research due to the following advantages: complete biocompatibility, ability to carry both lipophilic and hydrophilic compounds, protecting them from chemical degradation and transformation, decreased toxicity and increased therapeutic index of drug, etc. In the present work we explore the interaction between europium chelates (here referred to as V6 and V8) and model lipid membranes. Fluorescence intensity of membrane-incorporated probe p-terphenyl was found to decrease with enhancement of drugs concentration. The obtained results indicate that p-terphenyl fluorescence is quenched upon europium chelate incorporation into phosphatidylcholine liposomes. Quantitative characteristics of p-terphenyl fluorescence quenching by the drugs under consideration have been determined

The coordination abilities development in female students based on dance exercises

Передумови і мета дослідження. Фізична підготовленість студентів характеризується рівнем розвитку їхніх здібностей щодо виконання рухів різної складності. Однією з важливих складових в системі рухів є координаційні здібності. Мета дослідження – виявити рівень спеціальної та загальної координації студентів спеціальності «Хореографія» та надати рекомендації щодо розвитку координаційних здібностей в процесі вивчення Modern-Jazz танцю. Матеріал і методи. У дослідженні взяли участь студентки першого-другого року навчання (n=10, на початку дослідження (1 курс) вік - 17.4 ± 0.7 років) спеціальності «Хореографія». Використовувались тести для визначення рівня розвитку загальних та спеціальних координаційних здібностей. Визначався рівень координаційної підготовленості на початку навчання та після трьох семестрів навчання. Дослідження проведено протягом трьох семестрів (вересень 2019 р - грудень 2020 року). Навчальні плани з підготовки студентів не містять навчальної дисципліни «Фізичне виховання». Розвиток фізичних якостей є завданням спеціальних предметів з курсу фахової підготовки: відведено 16 годин на тиждень. Навантаження студентів за напрямом сучасного танцю становило 2 години на тиждень. Форми навчання за визначений період – очна (70%), дистанційна (10%), змішана (20%). У вересні 2019 р. та у грудні 2020 р. одні й ті ж самі студентки склали обрані тести. Результати. Констатовано достовірні зміни підвищення рівня координації у здібностях: керувати часовими та просторовими чинниками рухів; узгодженості рухів у комбінації; вестибулярній стійкості; музично-ритмічної координації (p<0.01). Пропонована методика передбачає, що на першому етапі вивчення модерн-джаз танцю координується два, три, чотири центри в одночасному паралельному русі. Висновки. Виявлено необхідність удосконалення навчальної програми вивчення джаз-модерн танцю, введення додаткових курсів до освітньої програми зі спеціальності «Хореографія». Техніко-лексична база джаз-модерн танцю у поєднанні зі спеціальною фізичною підготовкою дає широкі можливості для розвитку координаційних здібностей хореографів.Background and Study Aim. The physical fitness of students is characterized by the level of their abilities development to perform movements of varying complexity. One of the important components in the system of movements is coordination skills. The aim of the study is to identify the level of special and general coordination of students majoring in "Choreography" and provide recommendations for the development of coordination skills in the process of studying modern-jazz dance. Material and Methods. The study involved students of the first and second year of study (n = 10, at the beginning of the study (1 year) age - 17.4 ± 0.7 years) majoring in "Choreography". Tests were used to determine the level of development of general and special coordination skills. The level of coordination readiness at the beginning of training and after three semesters of training was determined. The study was conducted over three semesters (September 2019 - December 2020). Curricula for students’ training do not include the discipline "Physical Education". The development of physical qualities is the task of special subjects in the course of professional training: 16 hours per week. The workload of students in modern-jazz dance was 2 hours a week. Forms of study for a certain period - full-time (70%), online learning (10%), mixed (20%). In September 2019 and in December 2020, the same students passed selected tests. Results. The following significant changes in increasing the coordination level of the abilities were determined: to control temporal and spatial factors of movements; coordination of movements in combination; vestibular stability; musical-rhythmic coordination (p <0.01). The proposed technique assumes that at the first stage of studying modern jazz dance two, three, four centers are coordinated in simultaneous parallel movement. Conclusions. The need to improve the curriculum of modern jazz dance, the introduction of additional courses to the educational program in the major "Choreography". The technical and lexical base of modern jazz dance in combination with special physical training provides opportunities for the coordination skills development in choreographers

Fluorimetric study of interaction between europium coordination complexes and DNA

Lanthanide coordination complexes have found numerous applications in a number of areas, including laser techniques, fluorescent analysis, biomedical assays. Likewise, they exhibit antitumor properties. Eu(III) tris-β-diketonato complexes (EC) are newly synthesized compounds with high anticancer activity. Despite extensive studies, the detailed mechanism of their biological effects is far from being resolved. Examining the interactions between EC and biological molecules in model systems is essential for deeper understanding of the mechanisms behind their biological activity. In the present work we employed fluorescent probe acridine orange (AO) to investigate EC-DNA interaction. AO-DNA binding was followed by the marked fluorescence increase detected at 530 nm. EC addition suppressed this fluorescent changes. EC were found to differ in their ability to modify AO-DNA interactions. EC4 and EC6 have demonstrated the most pronounced effect on AO-DNA binding. AO-DNA complexation occurs predominantly via intercalation mode. EC are large planar structures, whose DNA intercalating ability was reported to increase with the planarity of ligands. It seems likely that AO and EC can compete for the binding sites on DNA molecule

Partitioning of europium chelate into lipid bilayer as revealed by p-terphenyl and pyrene quenching

Fluorescence quenching method is an effective tool for obtaining important information about different properties of biophysical and biochemical systems. In the present study quenching of fluorescent probes p-terphenyl and pyrene by europium chelate were observed in phosphatidylcholine liposomes. Europium chelates (EC) belong to a new class of potential antitumor drugs with high cytotoxic activity. These compounds are of particular interest for biomedical investigations and diagnostics, since their spectral characteristics are optimal for decrease of light scattering in biological patterns and background signal. However, the application of such drugs in a free form is limited by their high toxicity and metabolic instability. One efficient way to increase drug efficiency is based on using different drug delivery systems such as liposomes. Highly adaptable liposome-based nanocarriers currently attract increasing attention, because of their advantages, viz. complete biodegradability, ability to carry both hydrophilic and lipophilic payloads and protect them from chemical degradation and transformation, increased therapeutic index of drug, flexibility in coupling with targeting and imaging ligands, improved pharmacodynamic profiles compared to the free drugs, etc. The present study was focused on examination of lipid bilayer interactions of europium chelate (here referred to as V10). Fluorescence intensity of membrane- incorporated probes – pyrene and p-terphenyl – was found to decrease with increasing concentration of the drug, suggesting that V10 represents an effective quencher for these probes. This finding was explained by the drug penetration into hydrophobic membrane core, followed by the collision between V10 and probe molecules and subsequent fluorescence quenching. The acquired fluorescence quenching data were quantitatively interpreted in terms of the dynamic quenching model

Assessment of a single trial impact on the amplitude of the averaged event related potentials

Widely used in neuroscience the averaging of event related potentials is based on the assumption that small responses to the investigated events are present in every trial but can be hidden under the random noise. This situation often takes place, especially in experiments performed at hierarchically lower levels of sensory systems. However, in the studies of higher order complex neuronal networks evoked responses might appear only under particular conditions and be absent otherwise. We encountered this problem studying a propagation of interoceptive information to the cortical areas in the sleep-wake cycle. Cortical responses to various visceral events were present during some periods of sleep, then disappeared for a while and restored again after a period of absence. Further investigation of the viscero-cortical communication required a method that would allow labeling the trials contributing to the averaged event related responses–“efficient trials,” and separating them from the trials without any response. Here we describe a heuristic approach to solving this problem in the context of viscero-cortical interactions occurring during sleep. However, we think that the proposed technique can be applicable to any situation where neuronal processing of the same events is expected to be variable due to internal or external factors modulating neuronal activity. The method was first implemented as a script for Spike 2 program version 6.16 (CED). However, at present a functionally equivalent version of this algorithm is also available as Matlab code at https://github.com/george-fedorov/erp-correlations

CHARACTERIZATION OF AVIAN INFLUENZA H5N8 VIRUS STRAINS THAT CAUSED THE OUTBREAKS IN THE RUSSIAN FEDERATION IN 2016–2017

Objective of the study is to investigate biological properties of avian influenza virus strains that caused the outbreaks in Russia in 2016–2017.Materials and methods. The study was performed using advanced virological and molecular-biological methods in state-of-the-art equipment.Results and conclusion. In 2016, the outbreaks among wild birds and poultry caused by highly pathogenic avian influenza H5N8 virus have occurred in the territory of the Russian Federation. In May, 2016 an outbreak of H5N8 among wild birds was registered in the territory of the Republic of Tyva. In October-November, 2016 influenza virus H5N8 was isolated in the territory of the Republics of Tatarstan and Kalmykia, Krasnodar and Astrakhan Regions of Russia. In 2017 avian influenza H5N8 has become widespread in European part of Russia and caused multiple outbreaks among wild birds and poultry. Results of the investigations of the isolated strains show that all of them are highly pathogenic and belong to the clade 2.3.4.4. Molecular-genetic and virological analysis has revealed the differences between the viruses isolated in 2016–2017 and the virus of the same clade 2.3.4.4 that was isolated in 2014

Specific and highly efficient condensation of GC and IC DNA by polyaza pyridinophane derivatives

Two bis-polyaza pyridinophane derivatives and their monomeric reference compounds revealed strong interactions with ds-DNA and RNA. The bis-derivatives show a specific condensation of GC- and IC-DNA, which is almost two orders of magnitude more efficient than the well-known condensation agent spermine. The type of condensed DNA was identified as psi-DNA, characterized by the exceptionally strong CD signals. At variance to the almost silent AT(U) polynucleotides, these strong CD signals allow the determination of GC-condensates at nanomolar nucleobase concentrations. Detailed thermodynamic characterisation by ITC reveals significant differences between the DNA binding of the bis- derivative compounds (enthalpy driven) and that of spermine and of their monomeric counterparts (entropy driven). Atomic force microscopy confirmed GC-DNA compaction by the bis-derivatives and the formation of toroid- and rod-like structures responsible for the psi-type pattern in the CD spectra