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This study is devoted to exploring the possibilities of using reflective activities when studying the topic “Oxygen-containing organic compounds” in the school chemistry curriculum. The experience of domestic teachers in the application of reflective activities in chemistry lessons is analysed. Methodical recommendations for conducting lessons using different types of reflection in grades 8 and 9 have been developed. The results of a survey of teachers showed limited use of reflective activities, which are reduced to reflection on the emotional state and comprehension of students’ activities through questioning. Based on the analysis of scientific literature and teachers’ practical experience, lesson plans, instruction cards for laboratory and practical work with elements of students’ reflective activity have been developed that can be used in the practice of chemistry teachers. The developed materials are aimed at increasing students’ interest in the subject, encouraging the search for information, deepening students’ knowledge, and applying information and communication technologies in teaching.

Aim. To evaluate the suitability of the novel DNA-binding dye fb128 for real-time PCR applications, including amplification efficiency, fluorescence performance, PCR inhibition threshold, and melting curve analysis. Methods. UV-vis absorption and fluorescence spectroscopy, agarose gel electrophoresis, real-time PCR, melt curve analysis. Results. fb128 exhibited low intrinsic fluorescence and strong DNA-specific signal (ΔQ = 160.7). Optimal concentrations (0.2—1.6 μM) provided early Ct values without PCR inhibition, whereas the concentrations of ≥3 μM caused a delayin amplification or complete suppression. PCR efficiency with fb128 was 102.6%, within the optimal range for quantitative applications. Melting peaks with fb128 were stronger and appeared at 74.5 °C, 2.5 °C lower than with SYBR Green I, suggesting weaker dsDNA binding. Conclusions. fb128 demonstrates high amplification efficiency, strong fluorescent signal, broad concentration tolerance, and robust melting analysis performance. These properties establish fb128 as a competitive alternative to SYBR Green I for real-time PCR applications.

This paper presents numerical modelling of a thermally stratified energy source’s effect on the supersonic flow past a body “double-wedge - plate”. A multiple generation of the Richtmyer-Meshkov instabilities was obtained. These instabilities cause almost complete destruction of the bow shock front inside the source area and form a new multi-vortex mechanism of affecting the streamlined body. The defining parameters of the effect of stratified and homogeneous energy sources with equal values of total energy are analysed. The possibility of a significant decrease in the temperature at the vertex of the double-wedge and in the average front surface temperature due to the redistribution of source energy between layers has been established.

The problem of noise reduction in supersonic aircraft design is one of the key problems, the solution of which largely determines the speed of development of supersonic aviation as a whole. The present study examines the noise generation during flights of supersonic civil aircraft. The effect of a thermally stratified energy source (TSS) used to control the supersonic flow past a pointed cylinder aerodynamic model on the near-field and ground pressure signatures, as well as on the perceived loudness in decibels (PLdB) on the ground, is evaluated. The complex conservative difference schemes, Tomas’ waveform parameter method, and Stevens’ algorithm Mark VII are used for near-field modeling, obtaining the ground pressure signature, and the evaluation of the PLdB on the ground, accordingly. The fields of flow parameters and the dynamics of a drag force are researched at the variation of temperatures in layers of TSS and for different numbers of layers. Simulations showed that changing the surface pressure due to drag reduction does not necessarily imply a change in the PLdB on the ground. In particular, it has been shown that when performing the flow control at freestream Mach numbers 1.5–2 using TSSs with the number of layers from 2.5 to 7.5 and rarefaction parameters in the layers from 0.15 to 0.3, some weakening of the bow shock wave in the near-field pressure signature due to the effect of TSS occurs, and no additional noise impact on the ground is introduced.

Multilayer TiZrN/TiSiN coatings were deposited on steel substrate by the cathodic-arc evaporation technique. The TiZr (75:25 at. %) and TiSi (95:5 at. %) alloy cathodes served as evaporation sources. Scanning electron microscopy with energy-dispersive spectroscopy, secondary ion mass-spectrometry, X-ray diffraction and X-ray photoelectron spectroscopy were employed to investigate the microstructure, elemental composition, phase state and bonding structure of the deposited coatings. Nanoindentation and ball-on-disk tribology tests were used to measure the mechanical and tribological features of the coatings, such as hardness, elastic modulus, toughness, friction coefficient and wear rate. The results show that all multilayers were fcc structures with a strong preferred orientation along (111) plane. The coherent growth of the multilayers contributed to the formation of the fine-grained structure with crystallites of 9.2–11.6 nm size and a low level of residual stresses of− (3.5–5.3) GPa. All multilayer coatings exhibited high hardness up to 38.2 ± 1.15 GPa and elastic modulus up to 430 ± 12.9 GPa, indicating higher resistance against plastic deformation compared to TiZrN and TiSiN films. The result of ball-on-disk wear tests showed that the multilayer sample with the best structural features (modulation period of 20.4 nm, 0.86 at. % of Si, the crystallite size of 9.2 nm and residual stress of− 3.5 GPa) demonstrated the lowest friction coefficient of 0.844 and better wear rate of 3.32·10–5 mm3/N m.

The structural diversity and unique physicochemical properties of sulphated polysaccharides of red algae carrageenans (CRGs), to a great extent, determine the wide range of their antiviral properties. This work aimed to compare the antiviral activities of different structural types of CRGs: against herpes simplex virus type 1 (HSV-1) and enterovirus (ECHO-1). We found that CRGs significantly increased the resistance of Vero cells to virus infection (preventive effect), directly affected virus particles (virucidal effect), inhibited the attachment and penetration of virus to cells, and were more effective against HSV-1. CRG1 showed the highest virucidal effect on HSV-1 particles with a selective index (SI) of 100. CRG2 exhibited the highest antiviral activity by inhibiting HSV-1 and ECHO-1 plaque formation, with a SI of 110 and 59, respectively, when it was added before virus infection. CRG2 also significantly reduced the attachment of HSV-1 and ECHO-1 to cells compared to other CRGs. It was shown by molecular docking that tetrasaccharides—CRGs are able to bind with the HSV-1 surface glycoprotein, gD, to prevent virus–cell interactions. The revealed differences in the effect of CRGs on different stages of the lifecycle of the viruses are apparently related to the structural features of the investigated compounds.

This paper examines the effect of an asymmetrical energy source impact on the flow around supersonic aerodynamic bodies in a viscous heat-conducting gas (air) at Mach 2.5. The simulations are based on the Navier–Stokes equations with temperature-dependent viscosity and thermal conductivity. The dynamics of density, pressure, temperature, and heat fluxes were analyzed. Specific emphasis is placed on the effects of viscosity and thermal conductivity. Self-sustained oscillations of the flow parameters, lift and drag forces, and heat fluxes were obtained and studied. The mechanism of these oscillations was established, and the conditions of their presence in a flow in relation to the energy source characteristics and location were researched. Possible approaches for elimination of these oscillations were discussed.

Small rivers and other surface and groundwater sources form the basis for the functioning of river basin systems, shaping streamflow, providing water supply for rural areas, and supporting biodiversity. Local surface and groundwater sources are extremely sensitive to anthropogenic impacts and climate change. Changes in the quality and quantity of water in these sources are a primary factor influencing their use for various purposes, objects, methods, and technical conditions. Therefore, the research aimed to assess the quality of natural waters in the southern part of the Mohyliv-Podilskyi district, within the basin of the small river Kotlubayevka (a right tributary of the Dniester River). The primary research methods were analytical and statistical. The analytical method was used to determine the chemical composition of water samples according to standardized procedures. The statistical method was used to find out the reliability of measurement results and to provide a generalized assessment of water quality. Experimental results were processed for water samples based on ecological and sanitary criteria from eight potential sources of economic use located along the slopes of the Dniester and Kotlubayevka river basins, ranging from elevations of 215–206 to 78–55 m a.s.l. According to the ecological classification of surface water quality, the studied sources are classified as fresh oligotrophic (class I), and based on ion composition criteria, they are categorized as bicarbonate waters of type I ( > Ca 2+ + Mg 2+ ). The study identified a trend of water source contamination in the research area concerning copper, iron (Fe total ), and saprophytic bacteria Escherichia coli . A generalized ecological assessment of water was calculated using block indices for salinity composition, ecological-sanitary, and specific toxic indicators, which ranged from 2.33 to 3.00 along the slope above the river currents. The results indicate that the quality of the studied water sources ranges from “very good,” “clean,” to “good,” “fairly clean.” However, based on the block index for specific toxic indicators, the water quality tends to approach “fairly good” or “slightly polluted.” Among the water contaminants, elevated levels of Fe total , Cu 2+ , and E. coli primarily contribute to the deterioration of water quality and safety. Iron and copper contamination should be regarded as a natural factor, while microbiological contamination by E. coli should be considered a result of anthropogenic impact. The obtained research results impose limitations on the economic use of certain water sources, particularly in agricultural production.

Safe and reliable air transportation plays a significant role in modern society by facilitating connection, communication, and economic activity, which has been growing steadily for recent decades. Ensuring a safe, reliable, and efficient operation of the air transportation network is a central challenge in assuring smooth progress in modern and future aviation. This research addresses the problem of human-caused issues in aerial transportation by proposing, substantiating, validating, and designing automated flight situation advisory systems that can provide critical input to the crew in the cases of unexpected and challenging flight situations. It was shown that a proper design and use of these systems could be instrumental in managing flight situations and could eliminate or mitigate a significant fraction of human-cause faults and emergencies. It would expected that such an advisory system can become a proactive and cost-effective tool to improve safety and reliability in the operation of air traffic networks of today and tomorrow. The study’s main result is to assess the importance of factors influencing the development of recommendations by the advisory system.

The possibility of using different types of carrageenans (CRG) as matrixes for incorporating of echinochrome A (Ech) was investigated. Ech interacts with carrageenans and is incorporated into the macromolecular structure of the polysaccharide. The inclusion of Ech in carrageenan matrices decreased its oxidative degradation and improved its solubility. The changing in the charge and morphology of CRGs during binding with Ech was observed. The rate of Ech release from CRG matrices depended on the structure of the used polysaccharide and the presence of specific ions. The gastroprotective effect of CRG/Ech complexes was investigated on the model of stomach ulcers induced by indomethacin in rats. Complexes of CRG/Ech exhibited significant gastroprotective activity that exceeded the activity of the reference drug Phosphalugel. The gastroprotective effect of the complexes can be associated with their protective layer on the surface of the mucous membrane of a stomach.