Hydroxyapatites (HA) co-doped with Li⁺ and Bi³⁺ ions were synthesized by a microwave-assisted wet precipitation method to improve their structural, biological, and antibacterial performances. Dual doping of Li⁺ and Bi³⁺ ions led to an increase in crystallinity and crystallite size compared to single doping, indicating successful incorporation of dopants into the HA lattice. Co-doping also resulted in minor lattice distortions without altering the phase purity of HA. Biological characterization using adipose-derived mesenchymal stromal cells revealed that Bi incorporation enhanced cell proliferation and osteogenic activity, whereas excessive Li addition caused partial cytotoxicity. Interestingly, Li/Bi co-doping balanced this effect, leading to improved cell viability and differentiation compared to single-doped samples. Moreover, Li and Bi substitutions imparted significant antimicrobial activity against E. coli, S. aureus, P. aeruginosa, E. faecalis, and C. albicans, demonstrating the dual bioactive and antimicrobial nature of the material. The combined influence of Li⁺ and Bi³⁺ ions effectively modified the crystallinity and biological response of HA, suggesting that Li–Bi co-doped HA is a promising candidate for multifunctional coatings and bone tissue engineering applications.

Bacterial resistance and the demand for novel antibacterial strategies represent major challenges in contemporary medicine. In this study, zinc-doped hydroxyapatite (Zn-HA) samples with 3, 5, and 10 wt% Zn(II) were synthesized using wet precipitation synthesis and sintered at 700 and 800 °C. The samples were characterized by X-ray Diffraction, Fourier Transform Infrared Spectroscopy, Raman Spectroscopy, and Scanning Electron Microscopy. The antimicrobial properties of the Zn-HA were tested against four bacterial strains—Staphylococcus aureus, Enterococcus faecalis, Salmonella typhimurium, Escherichia coli—and the fungus Candida albicans. Both 5 wt% and 10 wt% Zn-HA effectively inhibited the growth of all microorganisms. Notably, 10wt% Zn-HA exhibited the best results, with inhibition rates of 50.2% against S. aureus, 36.5% against E. faecalis, 47.5% against P. aeruginosa, 31.8% against E. coli, and 24.7% against C. albicans. There were no significant differences in the growth of adipose mesenchymal stem cells between the prepared samples and the control. For osteogenic differentiation, dye uptake was 1.2 times higher for HA and 5 wt% Zn-HA, and 1.3 times higher for 3 wt% Zn-HA compared to the control. These results suggest that developed ceramics may be effective in regenerative medicine, paving the way for innovative treatments.

Addressing periprosthetic infections, which present significant healing challenges that often require revision surgeries, necessitates the development of novel antibacterial materials and implants. Current research focuses on creating materials that hinder bacterial adhesion, colonization, and proliferation in surrounding tissues. Boron (B)-containing compounds are known for their antibacterial properties and potential in bone metabolism for regenerative medicine. In this study, we synthesized B-containing tricalcium phosphate (0.3B-TCP) with 1.1 wt.% B content via precipitation from aqueous solutions and sintering at 1100 °C. X-ray diffraction confirmed the ceramic’s primary crystalline phase as β-TCP, with B evenly distributed according to energy-dispersive spectroscopy data. Electron paramagnetic resonance (EPR) data verified stable paramagnetic borate anions, indicating successful BO33− substitution for phosphate groups. The microstructural properties of 0.3B-TCP ceramic were assessed before and after soaking in a saline solution. Its bending strength was approximately 30 MPa, and its porosity was about 33%. 0.3B-TCP ceramic demonstrated significant antimicrobial efficacy against various bacterial strains and a fungus. Cytotoxicity evaluation using equine adipose tissue-derived mesenchymal stem cells and osteogenic differentiation assessment were conducted. The combination of antibacterial efficacy and good cytocompatibility suggests 0.3B-TCP ceramic as a promising bone substitute material.

Metered-dose nasal sprays (MDNS) are the most widely used for treating rhinitis. Medicinal preparations in the pharmaceutical market vary in their characteristics. To identify the most effective drug, it is necessary to compare the preparations regarding various parameters. The purpose of the research was to compare oxymetazoline MDNS of different brands regarding their dispersion qualities. To that end, nine oxymetazoline sprays available in the Russian market were chosen and analyzed considering their dynamic characteristics and the spraying dispersion composition. The research was conducted with the shadow photography method, the selection of which was justified by its simplicity, the possibilities for detecting the spray jet composition, the process of its formation in dynamics, and the possibility for measuring droplets of all forms. Momentary images of spray activation phases, as well as an averaged image of 100 shots of the spraying main phase, were obtained. According to a range of characteristics, such as spraying duration, a cone angle and cone structure, all the preparations were grouped into three categories. It was found out that the sprays from Group 2 had the best dynamic rates of dispersion, with Vicks Sinex having the best results. Regarding the distribution of particles of different size, the most optimal composition was found for the drugs from Group 2, particularly, Vicks Sinex and Afrin preparations. Hence, Vicks Sinex spraying regimen and microsprayer design were found the most effective for delivering the medicinal substance to the destination.

The phenomenon of evaporation from the surface of a liquid droplet into a neutral noncondensible gas was numerically studied by taking forced convection gaseous flow into account. The mathematical model considers the effects of surface tension, gravitational force, viscosity of both liquid and gaseous media, as well as the Stefan flow from the droplet surface, possible free gravitational convection, and the Marangoni convection in droplets, and it is designed to describe diffusion-limited evaporation. We consider the diffusion-limited evaporation process when the diffusive gas flux to the droplet surface is compensated by the convective Stefan flow from the surface. The results indicate an interaction of the liquid and gaseous media. Convective gas flows cause the liquid to move and a vortex to occur in the droplet. The flow velocities in a vortex are 103 times less than the characteristic velocity of forced convection flow in air. The droplet surrounded by gaseous flow changes its shape and oscillates, which causes a gas-density wave. Calculations have shown that the diffusion-limited evaporation rate does not change in the presence of forced convection, which contradicts most of the known experimental works. The possible reason for this discrepancy is the presence of non-equilibrium conditions at the liquid–gas interface in experiments. This leads to a consequent change of the evaporation mode to non-diffusive, while the numerical model postulates the Stefan condition and diffusion-limited evaporation.

Experiments on measuring the rate of evaporation of liquid sessile droplets into air show that the rate of evaporation increases in the presence of forced convection flows. However, data on the effect of convection on evaporation are often contradictory and should be clarified. The paper presents a numerical analysis of evaporation from the surface of a water droplet subjected to forced convection in the gas phase. The drop is located on a smooth horizontal isothermal substrate; the mode with constant contact angle is considered. The shape of the drop has axial symmetry, the same for the velocities and pressure. Forced convection compatible with the symmetry conditions are represented by flows directed downward along the axis of the system and diverging along the sides near the drop and the substrate. The mathematical model is constructed for evaporation controlled by diffusion in the gas phase and takes into account surface tension, gravity, and viscosity in both media, buoyancy and Marangoni convection. The results indicate the existence of the mutual influence of liquid and gaseous media. Thus, a drop vibrates under the influence of movements in the atmosphere, which generates a density wave in the gas: the drop «sounds». The magnitude of the velocity in a liquid is 50 times less than the characteristic velocity in air. It is found that the evaporation rate does not change in the presence of forced convection flows, which contradicts most of the experimental works. The reason for the discrepancies is supposed to be the appearance of nonequilibrium conditions at the boundary of the condensed phase: under these conditions, the evaporation regime ceases to be diffusional.

Statistical analysis of the results of molecular dynamics (MD) calculation of gas-phase “self-assembling” of nanoclusters during metal vapor condensation revealed the laws of energy transfer between metallic clusters and inert gas atoms. A model is proposed to determine the parameters of heat exchange between clusters and the environment at the initial stage of condensation. This model is based on averaged MD data on the interaction between small clusters and argon atoms. The parameters that can be used to transfer information from MD to a macroscopic condensation model are numerically determined. The results obtained can be used to describe nucleation to predict a nanoparticle size distribution in the production of metallic powders.

The results of the molecular-dynamic calculations of gas-phase nanocluster “self-assembly” during metal vapor condensation have been statistically analyzed parting terms of a computational scheme suitable for describing condensation. The laws of collisions and the growth of small copper clusters are revealed. The parameters that describe the interaction between clusters and metal atoms and are used to transfer information to a macroscopic nucleation model are determined. The results can be used for describing nucleation for predicting a nanoparticle size distribution in the production of metal nanopowders.

New derivatives of 2-oxo-4-vinyl-2H-chromene-3-carbonitrile have been synthesized by the Knoevenagel reaction of 4-methyl-2-oxo-2H-chromene-3-carbonitrile with aromatic and heteroaromatic aldehydes. The first hyperpolarizability β for the obtained compounds was calculated using M05-2X functional and 6-31+G(d) basis set; their optical properties and solvatochromism in solvents of various polarity were examined. The crystal structure for one representative of the synthesized compounds was determined by XRD.

Nanocrystalline antimony-doped ([Sb]/([Sb] + [Sn]) = 0–2 at %) SnO 2 powders have been synthesized by coprecipitation from solution. The composition, crystal structure, and microstructural parameters of the powders, as well as the antimony distribution in them, have been studied by laser mass spectrometry, X-ray diffraction, low-temperature nitrogen adsorption measurements, and IR spectroscopy. The reaction of the synthesized materials with oxygen has been studied in situ by electrical conductance measurements. Oxygen chemisorption on the surface of unmodified SnO 2 leads to predominant formation of the molecular species O 2(ads) - . Increasing the Sb concentration in the SnO 2 ‹Sb› samples increases the fraction of the monatomic species O 2(ads) - , which can be explained in terms of a combination of crystal-chemical and electronic factors.

Antimony-doped tin dioxide whiskers have been prepared by vapor growth in a tube furnace in a flowing mixture of argon and oxygen at a constant evaporation temperature. The antimony concentration was measured by laser mass spectrometry. Palladium was deposited by laser ablation. The palladium-modified whiskers exhibit a sensing response to CO at the level of its maximum allowable concentration in the workplace.

Методом роста из пара синтезированы нитевидные кристаллы диоксида олова, легированные сурьмой. Синтез проведен в трубчатой печи в потоке газовой смеси аргон + кислород при постоянной температуре испарения. Измерена концентрация введенной сурьмы методом лазерной масс-спектрометрии. Палладий наносили методом лазерного осаждения в вакууме. Показано, что нитевидные кристаллы, модифицированные палладием, обладают сенсорной чувствительностью по отношению к СО на уровне ПДКр.з.

Single crystal antimony-doped SnO2 whiskers have been synthesized by in situ doping process in horizontal flow reactor. The produced whiskers were modified with 0.1, 0.2, 0.5, 1 or 2 wt.% Pd. The processes of Pd particles growth and aggregation are described on the base of AFM and STEM data. Depending on the content of introduced Pd precursor, the various mechanisms (Volmer-Weber or Stranski-Krastanov) of Pd nanoparticles growth realize. The dependence of sensor signal to CO on Pd concentration has non-monotonous character determined by the size of Pd nanoparticles and their aggregation degree. The best sensor signal toward CO was observed for whiskers decorated with 0.1 wt.% Pd. This concentration corresponds to the presence of individual 3-5 nm Pd nanoparticles on the surface of the whiskers. (C) 2013 Elsevier B.V. All rights reserved.

A procedure for the determination of antimony and tin in tin dioxide whiskers, which were grown from a gas phase by the vapor-liquid-solid mechanism, was developed. The problem was difficult because the single whiskers are irregularly small in size and have a small weight (about 10−5 g). The procedure is based on the decomposition of a solid sample by cementation on zinc followed by the determination of analytes with the use of inductively coupled plasma mass spectrometry. The procedure developed is characterized by the detection limits of antimony of 0.01–0.03 μg/L and an RSD of 10%. An approach was proposed to estimate the antimony content of single whiskers.

Promising for the gas sensing one-dimensional tin oxide (SnO2) structures are reported. Antimony-doped SnO2 single crystal whiskers have been synthesized by in situ doping process in horizontal flow reactor. The surface of the whiskers was modified with different amount of Pd and investigated by means of atomic force microscopy (AFM). The obtained AFM data are explained by a model of Pd nanoparticles growth on the whisker surface. Sensor performance of the whiskers with Pd coating was studied and an increase of the sensor signal towards 10 ppm of carbon monoxide is found for the whiskers covered by certain amount of Pd.

Results are provided for evaluation of the possibility of preparing porous ceramic materials using synthetic wollastonite and silicon-containing components by chemical pore formation. The mechanism of pore formation, and also chemical processes during material drying and firing are studied. The physicochemical properties and microstructure of the material obtained are studied.

Tin dioxide whiskers have been grown from SnO vapor in a tube furnace in a flowing mixture of argon and oxygen at a constant source temperature, and the effect of the oxygen concentration in the carrier gas on the morphology, structure, and phase composition of the whiskers was studied. Single-crystal SnO2 whiskers can only be obtained in a narrow range of oxygen concentrations. Tin dioxide whiskers doped with different concentration of antimony (0–0.25 at.%) have been grown from SnO and Sb2O3 mixtures in a tube furnace in a flowing mixture of argon and oxygen at a constant source temperature. The whiskers are about 100 μm in length and well crystallized. They possess a high structural perfection. The influence of Sb on crystal structure, morphology, optical properties of the SnO2 whiskers is discussed. The electrophysical properties and sensitivity of individual whisker towards NO2 and CO have been investigated.