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Using a 36Cl radioactive label, we study the behavior of chloride ions during the adsorption interaction of hydroxyapatite (HA) with an aqueous solution of magnesium chloride at high concentrations. The kinetics of transfer of the label from the solution to the solid phase is investigated by liquid scintillation spectrometry, and the boundary concentrations of magnesium chloride at which this effect manifests itself are determined. At a concentration of the chloride ions above 0.6 mol/L, a topochemical reaction may occur with the incorporation of Cl– into the hydroxyapatite structure and the formation of an extraneous phase (whitlockite) or mixed Ca–Mg apatites with the partial replacement of OH by Cl.

A cell for studying the diffusion of therapeutic medical radionuclides into the macrolayer of the carrier sorbent was fabricated using 3D printing. The diffusion of ultramicroquantities of radium and strontium within a layer of watered hydroxyapatite was investigated. The value of the effective diffusion coefficient obtained using a one-dimensional nonstationary model was (1.0 ± 0.4) × 10–8 cm2/s for Ra and (3.0 ± 0.3) × 10–8 cm2/s for Sr.

The sorption of the actinium(iii) ions as 225,228Ac isotopes on hydroxyapatite (HAP) with various textures was studied. A “reverse” generator using an extraction chromatographic sorbent based on diglycolamide derivative (DGA Resin) was proposed for 228Ac production. The chemical yield of the product was ≥90%. The optimal acidity of the solution during sorption (pH 6–7) and the ratio of solid and liquid phases (20 mg of the sorbent per mL of the solution) were determined in preliminary experiments. The process kinetics is adequately described by pseudo-second-order model. The stationary state is reached rapidly (in 10 min) when a HAP suspension is used, whereas time (20–30 min) is needed for textured samples. The possibility of actinium ion diffusion within the bulk of these samples is shown. The diffusion coefficient of actinium estimated by diffusion in a wet HAP paste layer (one-dimensional model) was (1.0±0.2) • 10−7 cm2 s−1.

The dynamics of the 223Ra distribution in the volume of spherical hydroxyapatite (HAP) granules in the course of the 223Ra sorption from aqueous solutions onto sorbent particles and desorption was studied by α-track radiography. The optimum time of contact of the sample with a detector (exposure) was found, and a procedure for preparing experimental samples was suggested. Taking into account the density of the porous sorbent, the ranges of the α-particles emitted by 223Ra and its daughter products and of the recoil nuclei were estimated. The averaged effective range of the α-particles in HAP is ∼35 μm. A mathematical model of the Ra diffusion into the depth of the porous sorbent, taking into account the sorption, was developed on the basis of the parameters obtained. The effective diffusion coefficient was estimated at ∼3 × 10–5 cm2 s–1. Correlation be¬tween the sorbent particle size, radionuclide sorption time, and the absorbed dose produced by the particle in a biological tissue was demonstrated.

Modification of the cocrystallization method for producing hydroxyapatite (HAP) and an HAP-Cu combination to the enzymatic method using alkaline phosphatase leads to a change in the morphology, sizes, sorption capacity, type of particles, and conformity with the Langmuir and Freundlich models. A positive factor of the enzyme usage is an increase in the sorption capacity and the possibility to strictly control the particle sizes depending on the concentration of the enzyme used. The L2CuCl4 complex was synthesized on the basis of 2-aminopyrimidine (L), which is the precursor of many anticancer drugs, and the possibilities of introducing L2CuCl4 into the HAP composite were considered. The cytotoxicity data for various HAP and L2CuCl4 composites with respect to various types of leukemic cells as compared to lymphocytes of healthy donors showed antileukemic activity of the copper complex and the absence of HAP cytotoxicity in a wide range of concentrations.

The size control of materials is of great importance in research and technology because materials of different size and shape have different properties and applications. This paper focuses on the synthesis of hydroxyapatite in ultrasound fields of different frequencies and intensities with the aim to find the conditions which allow control of the particles size. The results are evaluated by X-ray diffraction, Transmission Electron Microscopy, morphological and sedimentation analyses. It is shown that the hydroxyapatite particles synthesized at low intensity non-cavitation regime of ultrasound have smaller size than those prepared at high intensity cavitation regime. The explanation of observed results is based on the idea of formation of vortices at the interface between phosphoric acid and calcium hydroxide solution where the nucleation of hydroxyapatite particles is taken place. Smaller vortices formed at high frequency non-cavitation ultrasound regime provide smaller nucleation sites and smaller resulting particles, compared to vortices and particles obtained without ultrasound. Discovered method has a potential of industrial application of ultrasound for the controlled synthesis of nanoparticles.

In this study, we report a method for the suppression of Escherichia coli (E. coli) vitality by means of therapeutic ultrasound irradiation (USI) using biocompatible silicon nanoparticles as cavitation sensitizers. Silicon nanoparticles without (SiNPs) and with polysaccharide (dextran) coating (DSiNPs) were used. Both types of nanoparticles were nontoxic to Hep 2 cells up to a concentration of 2 mg/mL. The treatment of bacteria with nanoparticles and application of 1 W/cm2 USI resulted in the reduction of their viabilities up to 35 and 72% for SiNPs and DSiNPs, respectively. The higher bacterial viability reduction for DSiNPs as compared with SiNPs can be explained by the fact that the biopolymer shell of the polysaccharide provides a stronger adhesion of nanoparticles to the bacterial surface. Transmission electron microscopy (TEM) studies showed that the bacterial lipid shell was partially perforated after the combined treatment of DSiNPs and USI, which can be explained by the lysis of bacterial membran...

The condensation of 1-(ferrocenylalkyl)pyrazole-3-carbaldehydes with 4′-aminotetraphenylporphyrin, followed by reduction with NaBH(OAc)3 in 1,2-dichloroethane, provides a convenient method for the synthesis of 5-{4-[({1-[1-(ferrocen-1-yl)alkyl]-5-methyl-1H-pyrazol-3-yl}methyl)amino]phenyl}-10,15,20-triphenylporphyrins which exhibit pronounced cytotoxicity against Staphylococcus aureus under ultrasonic irradiation.

Using bacterial model systems, it was shown that the addition of the soluble compound sodium salt of cobalt octacarboxyphthalocyanine (teraphtal) to a medium reduced the proportion of bacteria that survived in an ultrasonic field. It was hypothesized that in the bacterial environment teraphtal forms a solid phase that under exposure to an ultrasonic field destroys the structures that are adjacent to the nanocrystals due to local cavitation processes.

The experience of the joint research by the Department of Chemistry, Lomonosov Moscow State University, and the Federal State Budgetary Scientific Institution “N.N. Blokhin Russian Cancer Research Center” (FSBSI “N.N. Blokhin RCRC”), on the application of medium-intensity ultrasound in combination with chemotherapy and sonosensitizers in the treatment of cancer diseases was summarized. A cycle of preclinical trials showed that the method allows enhancing the damaging effect of ultrasound on the tumor, while no metastasis-promoting and toxic effects are exerted. The combined method is being currently tested in clinical trials.

Possibility of creation of materials with transport properties operated by ultrasound on the basis of thermosensitive hydrogels modified by a solid phase of inorganic compounds is shown. The kinetic model of drug release from the hydrogel matrix, which allows to optimize the parameters of ultrasound exposure is proposed. Various options of devices with operated ultrasound an outlet of medicinal substance are offered.

Specific radioactivity of tritium-labeled nanodiamonds obtained by a tritium thermal activation method can be increased by presonication only if this treatment reduces the diameter of nanodiamond aggregates in an aqueous suspension by a factor of 2 or more.

This paper describes the features of zonal crystallization at high speeds of the process. Processes of heat release and change of the state of reagents in solution, associated with their high concentration, were taken into account. The kinetics of crystal growth in gel medium was investigated. The control algorithm for permeability of layer with precipitated solid phase was identified. The parameters defining the localization of the crystal growth were discussed. The possibility of forming an impermeable plug with specified location was shown. These results are of interest for the solution of certain medical problems associated with the controlled transport of drugs.

It was shown for the example of CsI aerosol that the aggregation of primary aerosol particles could be described in terms of either the discrete or continuum model. This conclusion was drawn on the basis of experiments performed by the method that allowed primary particles to be observed against the background of their aggregates and transfer of primary particles from aerosol volume to a collector to be provided. The size of primary particles on the collector was determined by transmission electron microscopy. It was found that, under the conditions used, the size distribution of primary particles corresponded to the Fokker-Planck equation.

Taking CsI aerosol as an example, it was shown that growth of primary aerosol particles can be described in terms of both discrete and continuum models. This conclusion is based on the results of experiments carried out using a method that makes it possible to distinguish primary particles against the background of their aggregates, to provide a complete transfer of the primary particles from aerosol bulk to a collector, and to determine the particle sizes by transmission electron microscopy. Under the conditions studied, the size distribution of the primary particles is described by a Fokker—Planck type equation.

Discrete and continual versions of the rate equation for the size distribution function of primary aerosol particles were formulated. With the CsI aerosol as example, it was shown that coarsening of primary aerosol particles can be described in terms of both discrete and continual models. This conclusion is based on the results of experiments performed by the procedure that makes it possible to reveal primary particles against the background of their aggregates, ensures complete transfer of primary particles from the aerosol volume to the collector, and allows determination of their size on the collector by electron microscopy. Under the examined conditions, the size distribution of primary particles is described by an exponential function.

The contamination of water flow in Soldatskaya Cave is studied. Groundwater of the cave was found to feature bacterial pollution. The distribution of bacterial cells over the karst system is examined. The contamination is shown to correlate with anthropogenic load. The major hydrodynamic and physicochemical characteristics of groundwater flow are evaluated, and their correlation with self-purification is demonstrated. Components of the karst water self-purification mechanisms are analyzed. The possibility to intensify karst water self-purification is considered.

Authors’ concepts on the use of solid-phase sonosensitizer nanoinclusions in biological structures as ultrasonic energy concentrators in the therapy of oncological diseases are developed. The possibility of directed synthesis of nanoparticles and their aggregates in tumor tissue depending on its growth features is discussed. It was found that acoustic effects in polymer structures containing solid-phase inclusions depend on the nature of these inclusions and their bond with the polymer matrix. Using model gel systems, it was shown that solid-phase sonosensitizers enhance local thermal effects and amplitude-dependent scattering of ultrasound during its propagation in gel. Experimental studies on animals showed that the ultrasound exposure of malignant tumors containing nanoparticles of gold and some complex compounds results in a significant therapeutic effect.

A kinetic model of the crystallization of substances in the volume of an agglomerate of many microparticles or in a polymeric gel in solution with a given composition and temperature was formulated. The model takes into account the diffusion of the crystallizing substance from outside into the space between microparticles in an agglomerate or between polymeric globules in a gel and then from this space into the volume of microparticles (globules) with the simultaneous nucleation and growth of microcrystals of the crystallizing substance. The possibility of simultaneous diffusion of several crystallizing substances, which chemically react with each other to produce product microcrystals, heating of the gel (solid) by the heat of crystallization, pushing the solution out from the space between microparticles, and changes in the volume of the gel (solid) as a result of crystallization is considered. The model was used to develop a classification of crystallization types in gels and porous solids and interpret several phenomena described in the literature. A hypothesis was advanced concerning some unknown phenomena related to crystallization.

Aggregates of calcium carbonate microcrystals precipitated from a highly supersaturated aqueous solution were found to form in two stages. At the first stage, high-porosity disordered aggregates (floccules), and at the second, low-porosity ordered aggregates (agglomerates) formed. The application of an acoustic field with a frequency of 2.64 MHz and radiation power 3 W/cm2 did not influence the kinetics of formation of microcrystals but accelerated aggregation by four orders of magnitude. This effect was explained by the sonostimulated desolvation of microcrystals colliding with the surface of aggregates and the corresponding decrease in the probability of the detachment from aggregates after collisions. The formation of microcrystals and aggregates in an acoustic field can be described by a Fokker-Planck-type equation. Taking this into account, a model of sonostimulated agglomeration revealing the direction of further investigations was formulated.