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The propagation of elastic waves in porous media saturated by a liquid or gas is considered. Based on general ideas of microstructure homogenization and a phenomenological approach, the governing equations for waves in a continual poroelastic medium are obtained. The proposed approach provides formulas for effective elastic moduli of the homogenized two-phase media in general anisotropic form. The derived model is compared with the classical Biot's model of an isotropic poroelastic medium and the Biot's moduli are obtained as functions of the porosity. The influence of the porosity on Rayleigh waves in a poroelastic half-space is under consideration. The inverse problem for porosity detection using surface waves is discussed too. [ABSTRACT FROM AUTHOR]

The three-dimensional problem of the modelling of elastic wave propagation in a multi-layered periodic composite with a doubly periodic array of interface rectangular delaminations or planar voids using the boundary integral equation method is considered. The boundary integral equation with unknown crack opening displacement vector is formulated using the Floquet theorem and solved using the Galerkin method at the reference delamination. The influence of the characteristics of the doubly periodic array on the transmission and diffraction of plane transverse and longitudinal elastic waves is analyzed. [ABSTRACT FROM AUTHOR]

The proposed development is devoted to the problems of implementation of Smart-oriented software and analytical tools based on Big Data in architecture and construction management. The goal of this toolkit is prognosis and monitoring of architectural components of the city as a dynamic system. Relevance of its implementation lies in optimizing the principles of functioning of the architectural structure of the city with the calculation of its impact on the processes of functioning of other urban subsystems. Experience of modernization of the obsolete housing stock on the territory of the former USSR has shown how domestic realities differ from the global European ones. This fact became a spontaneous motive for the development of the concept of innovative software product called "Program complex for modeling the city as a dynamic system", which is carried out at the department of innovative technologies design of the architectural environment of KNUCEA. [ABSTRACT FROM AUTHOR]

The aim of the research was to investigate the utility of components of metallurgical wastes in the production of high temperature refractory bricks based on rich and poor chromium spinel powder (HSP) waste produced by self-propagating high-temperature synthesis method. The series of experiments on the obtaining of carbon containing refractories based on the waste of rich and poor chrome spinel powder were conducted in a muffle furnace. The effect of the adding of rich and poor chromium waste on refractories' mechanical and thermal properties were detailly studied. Thermodynamic calculations and thermochemical modeling were performed between the components of metallurgical waste using the HSC Chemistry software. The diagram and graph were constructed that demonstrate the possibility of forming high quality refractory materials under experimental conditions using calculation modules. The compressive strength value of obtained sample was at competitive level in accordance with series of mechanical tests. [ABSTRACT FROM AUTHOR]

The article presents the numerical-analytical technique for solving the problem of braces stability for steel lattice supports with single-bolted joints in a complex stress state which allows to increase the bearing capacity of lattice structures of overhead power lines up to 18%. Is considered the general stability of a spatial lattice truss with inclined belts for the most common type of lattice used in supports of overhead power transmission lines (OHPL). The solution to this problem is implemented in the software package MS «Excel» using the apparatus of nonlinear mathematical search for unknown parameters. Is performed the analysis of the obtained coefficients of braces' effective lengths for the lower section of the intermediate support 1P330-1 and anchor-angular support U220-2+9. Based on the developed methodology for stability design of the OHPL supports' lattice were obtained the new values of coefficients of effective lengths for lattice elements, which are up to 20% lower than the existing ones. When solving the stability equation, attention is paid to the joint work of the structural elements of the overhead line support shaft. On the basis of the developed technique, new regularities have been obtained for determining the buckling coefficients for the lattice of steel supports, which make it possible to increase the bearing capacity of metal structures of overhead transmission power lines. The proposed new regularities for determining the buckling coefficients make it possible to increase them from 1% to 39% when the flexibilities of elements change from 10 to 220 in comparison with the Russian and Ukrainian design standards. An improved algorithm for calculating OHPL supports, taking into account the obtained dependencies for effective lengths and buckling coefficients, is implemented in the optimal design software «MISI1», developed at the Donbas National Academy of Civil Engineering and Architecture. [ABSTRACT FROM AUTHOR]

Relevance and purpose of the work: the difficult ecological situation that has developed to date was largely caused by the imperfection of the state policy aimed at waste disposal. As a type of economic activity (a branch of the national economy), the waste-processing industry is currently in its infancy and needs regulation, which will help to activate the internal resource capabilities of the participants to carry out effective integration interaction aimed at increasing the efficiency of their activities, which meets the requirements of the digital economy. The emergence of digital platforms as a new business model makes it possible to expand the range of potential actors in the industry space, see their innovative opportunities and quickly implement them. Methods: the methodological basis of the research was formed by an integrated approach, which includes general scientific and special methods (analysis, generalization, synthesis, modeling), which made it possible to solve the assigned tasks. Results: the paper substantiates the feasibility of creating a single digital platform for a waste processing cluster in order to optimize communications between its stakeholders, and also suggests principles of its construction for the industry in question. Based on the considered basic business models and scenarios for the formation of a digital platform, an estimate of its cost for various participants in the waste processing cluster is proposed. Conclusions: the development of a digital cluster platform based on the identification of information flows arising in the waste processing cluster will meet the needs and interests of its main participants, which will contribute to the development of the industry. [ABSTRACT FROM AUTHOR]

Electronic learning tools provide with the application of multi-media technologies; they allow to improve the quality of information, giving it brightness, colourfulness, dynamism; they provide feedback using interactive interaction and much more. By now, electronic learning tools are becoming more diverse. Without electronic learning tools, it is impossible to conduct any electronic lesson, since they are its basis, especially during the pandemic that the world community has faced. Currently, electronic learning tools are quite diverse and at the same time they are improving and being implemented more and more every time, giving the lesson more colorful and accessible information. [ABSTRACT FROM AUTHOR]

In road building, industrial, agricultural and other hydraulically driven machines, hydraulic shock occurs which causes the formation of micro-cracks in the high pressure hoses inner sheath, provoking premature hose pipes failure and unauthorised ejection of hydraulic oil into the atmosphere with consequent environmental pollution. There are methods to protect the hydraulic drive based on the principle of automatic disconnection of hydraulic oil supply in case of hose pipes damage. However, the known protection methods do not completely solve the mentioned problem, since the hydrodynamic alternating loads caused by a hydraulic shock, when the locking device of the hydraulic drive protection system is triggered, not only destroy hose pipes, but also lead to an oscillatory process of the locking device gate, the increase in the damaged hydraulic line overlap time and, as a consequence, to the increase of the hydraulic oil losses. To eliminate the above disadvantages, the known devices parametric characteristics theoretical and experimental research was carried out; a new technical solution based on an acoustic method for microcracks diagnosing on the hydraulic line inner shell with subsequent operator informing about the fault and automatic shutdown of hydraulic oil supply, was developed and patented by the authors. [ABSTRACT FROM AUTHOR]

In this work, the bioactivity of composites containing up to 60% calcium phosphates in polylactide (PLA) with the addition of glycerol and sorbitol is studied. The use of a mixture of highly dispersed calcium phosphates as the mineral phase of composites with PLA ensures the resorption of the material in the PBS solution. The degree of resorption is determined by the content of calcium phosphates and increases in proportion to its growth, as a result of which the weight loss by the end of the fourth week varies from 6 to 15% in samples with a phosphate content of 20 to 60%, respectively. [ABSTRACT FROM AUTHOR]

Samples of refractory products based on metallurgical production wastes were obtained and studied at various ratios of components in a wide temperature range of 100–1650 °C. Their ultimate compressive strength (MPa), refractoriness, heat resistance, density (g / cm3) and shrinkage (%) were determined. A graphical representation of changes in the mechanical properties of fired refractories in the coordinates: ultimate strength in compression, MPa (σ) and firing temperature (T ° C) is presented. [ABSTRACT FROM AUTHOR]

Despite significant advances in medicine, the development of new drugs for cancer treatment remains an urgent task. Only in the last 10 years the number of patients with cancer has increased several times. Therefore, it is advisable to look for new ways to fight against cancer. To solve this problem, new nanotechnology advances and various systems based on nanoparticles are used. One of antitumor treatments may be the use of nanostructured composites based on MgO/Mg2Al(OH)7. In this work, these nanostructures were obtained by water oxidation of an electric explosive nanopowder of AlN/Al composite in the presence of magnesium chloride solution. The effect of synthesized nanostructures on the viability of tumor cells Neuro-2a was studied. MgO/Mg2Al(OH)7 nanostructures have been shown to exhibit more pronounced antitumor activity than magnesium hydroxide both alone and in combination with the chemotherapeutic drug doxorubicin. [ABSTRACT FROM AUTHOR]

In the present study ability of aluminum hydroxide and calcium oxide based nanostructured composites to potentiate activity of common pharmaceutical anticancer agent—doxorubicin. The potentiating ability was examined by evaluation of changes in Neuro-2a neuroblastoma cell line morphofunctional characteristics. To determine interrelation between the composites potentiating ability and their physicochemical characteristics, morphology of synthesized nanostructured materials, their phase composition, charge, textural and acid-base properties were investigated. It was found that CaO/Ca2Al(OH)7 composite nanostructures significantly suppress tumor cells proliferation when combined with doxorubicin. In our view, composites potentiating ability is associated with their ability to increase pH value of a cell microenvironment, thus increasing doxorubicin dissociation and lightening its cell membrane penetration. [ABSTRACT FROM AUTHOR]

Introduction of in homogeneities such as cracks and electrodes into a phononic crystal (PnC) may lead to the appearance of additional band-gaps or, vice versa, pass-bands, wave resonances or other physical phenomena. This study focuses on the modelling of the propagation of plane elastic waves through a PnC with multiple in homogeneities such as cracks and electrodes.The PnC is composed of two-layered periodically situated unit-cells consisting of elastic or piezoelectric layers. The cracks are simulated as infinitesimal cuts with stress-free faces, while electrodes are defined by a given voltage (an electrical potential).Wave-fields in the considered layered PnC are determined employing the boundary integral equation method. [ABSTRACT FROM AUTHOR]

Nanoparticles with a spinel structure were obtained by the method of electric explosion of Fe and Cu wires in an oxygen-containing atmosphere. Their characteristics and antimicrobial activity were investigated depending on the energy input into dispersible conductors. As the input energy increases, the specific surface area of the samples obtained increases, which indicates the formation of smaller particles. XRD analysis shows CuFe2O4 phase. Studies have been conducted on the antimicrobial activity of samples using the broth dilution method. It was shown that the obtained copper ferrite nanoparticles with respect to the bacterial strains of E.coli and MRSA have antibacterial effects in varying degrees. Nanoparticles with a large specific surface area have the highest antibacterial activity. [ABSTRACT FROM AUTHOR]

Using the electrical explosion of two wires in the oxygen-containing atmosphere, the authors have produced (CuxMe1–x)O nanoparticles, where Me is Zn or Ag. Their physicochemical characteristics, antimicrobial activity and cytotoxicity have been studied. It has been found that synthesized nanoparticles (CuxMe1–x)O have similar sizes (80– 110 nm) and a positive zeta potential of about 20 mV. The particles are mostly spherical or near-spherical. The elemental analysis of the nanoparticles (Cu0.50Zn0.50)O shows that copper and zinc are unevenly distributed over the volume of nanoparticles, and form ZnO and CuO. The nanoparticles (Cu0.48Ag0.52)O are represented by Cu2O, CuO phases and metallic silver. The components are also unevenly distributed among the particles. By studying the antimicrobial activity of the samples obtained with respect to Escherichia coli ATCC 25922 and a clinical strain of methicillin-resistant Staphylococcus aureus MRSA ATCC 43300, the authors have found that composite nanoparticles more effectively inhibit the growth of bacteria than particles produced by electrical explosion of single wires (Cu, Zn, Ag) under similar conditions. [ABSTRACT FROM AUTHOR]

The topicality of temperature monitoring for tissues in the electrosurgical treatment of uterine myoma has been substantiated. A method for estimating the heating temperature of biological tissue based on measuring the relaxation frequency of the processed biological tissues is proposed. Geometrical and mathematical models were developed for calculating the thermoelectric characteristics of biological tissues when exposed to high-frequency electric current. A computational experiment was carried out to study the effect of the heating temperature of biological tissue in the resection area on its relaxation frequency. As a result of the study conducted, a linear dependence was established between the heating temperature of biological tissues and its relaxation frequency for a given needle electrode geometry. [ABSTRACT FROM AUTHOR]

The article deals with the temperature distribution in the rhinophyma resection area and determines the duration of exposure. The geometrical and mathematical models of layered resection of rhinophyma tissue have been developed to solve this problem, and a computational experiment has been conducted to calculate the heating temperature of biological tissues in the rhinophyma resection zone. As a result of the research, a significant non-uniformity of temperature distribution along the length of the electrode working part - a triangular loop, has been established, and its minimum duration for reaching the resection temperature has been determined for the given parameters of the output action. [ABSTRACT FROM AUTHOR]

Nowadays, the use of hierarchically built structures in biology and medicine arouses much interest. The aim of this work is to review and summarize the available literature data about hierarchically organized structures in biomedical application. Nanoparticles can serve as an example of such structures. Medicine holds a special place among various application methods of similar systems. Special attention is paid to inorganic nanoparticles based on different metal oxides and hydroxides, such as iron, zinc, copper, and aluminum. Our investigations show that low-dimensional nanostructures based on aluminum oxides and hydroxides have an inhibitory effect on tumor cells and possess an antimicrobial activity. At the same time, it is obvious that the large-scale use of nanoparticles by humans needs to thoroughly study their properties. Special attention should be paid to the study of nanoparticle interaction with living biological objects. The numerous data show that there is no clear understanding of interaction mechanisms between nanoparticles and various cell types. [ABSTRACT FROM AUTHOR]

In the present work, toxicity of nanostructures based on aluminum hydroxide, magnesium oxide, and the influence of their combinations on morphofunctional characteristics of the normal and cancer cell lines was evaluated. Nanostructures were characterized by transmission (TEM) and scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), low temperature nitrogen adsorption, and dynamic light scattering method. It was found that lowdimensional aluminum oxide structures affect cancer cells rather than normal cells. It was established that magnesium oxide nanoparticles and nanostructured aluminum oxyhydroxide are more toxic for cancer cells than these nanostructures in combination in the same concentration. Probably, differences in the proliferative activity for both normal and cancer cells after contacting with synthesized nanostructures are provided by the changed cell microenvironment. [ABSTRACT FROM AUTHOR]

Nanoparticles and nanostructured materials are one of the most promising developments for cancer therapy. Gold nanoparticles, magnetic nanoparticles based on iron and its oxides and other metal oxides have been widely used in diagnosis and treatment of cancer. Much less research attention has been payed to nanoparticles and nanostructures based on aluminum oxides and hydroxides as materials for cancer diagnosis and treatment. However recent investigations have shown promising results regarding these objects. Here, we review the antitumor results obtained with AlOOH nanoparticles. [ABSTRACT FROM AUTHOR]

Nanoparticles and nanostructured materials are one of the most promising developments for cancer therapy. Gold nanoparticles, magnetic nanoparticles based on iron and its oxides and other metal oxides have been widely used in diagnosis and treatment of cancer. Much less researchers' attention has been paid to nanoparticles and nanostructures based on aluminum oxides and hydroxides as materials for cancer diagnosis and treatment. However, recent investigations have shown promising results regarding these objects. Here, we review the antitumor results obtained with different aluminum oxide/hydroxide nanoparticles and nanostructures. [ABSTRACT FROM AUTHOR]

Nowadays there are new magnetic nanostructures based on bioactive metals with low toxicity and high efficiency for a wide range of biomedical applications including drugs delivery, antimicrobial drugs design, cells' separation and contrasting. For such applications it is necessary to develop highly magnetic particles with less than 100 nm in size. In the present study magnetic nanoparticles Fe, Fe3O4 and bimetallic Cu/Fe with the average size of 60-90 nm have been synthesized by electrical explosion of wire in an oxygen or argon atmosphere. The produced nanoparticles have been characterized with transmission electron microscopy, X-ray phase analysis, and nitrogen thermal desorption. The synthesized particles have shown antibacterial activity to gram-positive (S. aureus, MRSA) and gramnegative (E. coli, P. aeruginosa) bacteria. According to the cytological data Fe, Fe3O4 and Cu/Fe nanoparticles have effectively inhibited viability of cancer cell lines Neuro-2a and J774. The obtained nanoparticles are promising for new antimicrobial drugs and antitumor agents' development. [ABSTRACT FROM AUTHOR]

Nano-dimensional materials have recently attracted much attention with respect to their potential role in medicine. Physical mechanisms of interaction of nanoparticles with tumor cells will help to develop new methods for cancer disease treatment. Based on aluminum oxide phases, positively charged low-dimensional structures have different shape: agglomerates of nanosheets, nameplates, cone-shaped nanoaggregates were synthesized with the help of aluminum nanoparticles. The cytotoxicity effect of these low-dimensional structures on A549, HeLa, MDA, PyMT tumor cells was studied. It was shown that agglomerates of nanosheets were more toxic for investigating cell lines. Agglomerates of nanosheets had a medium toxic effect at a concentration of 10 mg/ml while nameplates and cone-shaped nanoaggregates were nontoxic. The toxic effect of agglomerates of nanosheets correlates with their shape, mainly the presence of multiple edges. [ABSTRACT FROM AUTHOR]

In recent years, researches have paid much attention to the physical, chemical, biophysical and biochemical properties of a cell surface. It is known that most of the cells' surfaces are charged. This charge depends on the biochemical structure of the cell membranes. Therefore, measurement of a cell surface charge is a significant criterion that gives information about the cell surface. Evaluation of the cells zeta-potential is important to understand the interaction mechanisms of various drugs, antibiotics, as well as the interaction of nanoparticles with the cell surface. In this study, we use the dynamic light scattering method to detect the zeta-potential change of Neuro-2a tumor cells. It has been observed that zeta-potential shifted to negative values after exposure to metal oxide nanoparticles and inducing apoptosis. [ABSTRACT FROM AUTHOR]

The paper presents the toxicity evaluation of nanostructures on the basis of alumina of different shape (nanofibers, nanoplates, nanosheets, nanosheet agglomerates) and with similar physical and chemical properties (particle size, specific surface area, phase composition, and zeta potential). The nanostructures were examined by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), low-temperature nitrogen adsorption, and dynamic light scattering (DLS). The cytotoxicity of nanostructures was estimated using L929 fibroblast cells and Neuro-2a tumor cells. It has been found that the L929 cells are less subject to the influence of alumina nanoparticles than the Neuro-2a tumor cells. Probably, the differences in the proliferation activity of normal and tumor cells in contact with the synthesized nanostructures are due to a change in the pH of the cell microenvironment. [ABSTRACT FROM AUTHOR]

Core-shell micro/nanostructures were fabricated by the reaction of Al/Cu bimetallic nanoparticles with water. Al/Cu nanoparticles have been obtained using the method of simultaneous electrical explosion of a pair of the corresponding metal wires in an argon atmosphere. The nanoparticles are chemically active and interact with water at 60°C to form core-shell micro/nanostructures. The obtained products were characterized by means of X-ray diffraction, scanning electron microscopy, transmission electron microscopy and dynamic light scattering and the nitrogen adsorption method. The antibacterial activity of the synthesized structures was investigated against E. coli and St. aureus. The toxic effect of these nanostructures against the Neuro-2a neuroblastoma cell line was investigated. AlOOH/Cu nanostructures are shown to inhibit cell proliferation. The AlOOH/Cu nanostructures are good candidates for medical applications. [ABSTRACT FROM AUTHOR]

Today there is a growing demand for safe and efficient antimicrobial dressings for infected wound treatment. The antimicrobial sorption material for VitaVallis dressings was produced by one-stage oxidation of aluminum nanopowder in water in the presence of fibrous acetylcellulose matrix. Scanning electron microscopy revealed that the material is made up of fibers of diameter 1.5-3.0 µm with adhered agglomerated alumina nanosheets. An antimicrobial study revealed a high inhibitory effect of VitaVallis against the growth of gram-negative (E.coli, P. aeruginosa) and gram-positive (S. aureus) strains. The antimicrobial activity of the dressing against microbial pathogens on the wound surface was demonstrated in in vivo experiments on male rats. The dressing was also tested on volunteer patients. The testing showed reduction of the wound healing period, accelerated cleaning of the infected wound and enhanced tissue regeneration in the wound. The results demonstrate that the VitaVallis dressing can be used for the treatment of deep infected wounds. [ABSTRACT FROM AUTHOR]

Low-dimensional alumina structures differing in shape and size were synthesized. The influence of the low-dimensional structures on proliferation of normal and tumor cells was studied. [ABSTRACT FROM AUTHOR]

In the study, we estimated the cytotoxicity of alumina nanoparticles differing in shape (nanofibers, nanoplates, nanosheets, agglomerates of nanosheets) and close in physicochemical properties (particle size, specific surface area, phase composition, and zeta potential). The alumina structures were characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) data, low-temperature nitrogen adsorption, and dynamic light scattering (DLS). The cytotoxicity was estimated on fibroblast cells of the L929 line. It was found that a more adverse effect on the cells was exerted by alumina nanofibers and nanosheets. The action of nanosheets on the cells was inhibitory and was of about the same level, irrespective of the observation period. The effect of alumina nanosheet agglomerates and nanoplates on the cell proliferation was weak even at an exposure time of 72 h. [ABSTRACT FROM AUTHOR]

Important neutrino results came recently from Borexino, a massive, calorimetric liquid scintillator detector installed at the underground Gran Sasso Laboratory. With its unprecedented radiopurity levels achieved in the core of the detection medium, it is the only experiment in operation able to study in real time solar neutrino interactions in the challenging sub-MeV energy region. The recently achieved breakthrough observation of the fundamental pp flux, the precise measurement of the 7Be solar neutrino flux, and the results concerning the pep, 8B and CNO fluxes, together with their physics implications, are described in this work. Moreover, the detector has also provided a clean detection of terrestrial neutrinos, from which they emerge as a new probe of the interior of the Earth. [ABSTRACT FROM AUTHOR]

Low-dimensional structures consisting of pseudoboehmite nanopetals are synthesized by hydrolysis of electroexplosive aluminum nanopowder. The physical and chemical properties of the synthesized nanostructures are studied, such as morphology, particle size, specific surface area, phase composition, and zeta-potential. The production of a hybrid material on the basis of cellulose acetate microfibers and low-dimensional pseudoboehmite structures is described. Using the example of gram-negative and gram-positive bacteria, we show the microorganism adsorption capacity of pseudoboehmite nanopetals and the hybrid material. [ABSTRACT FROM AUTHOR]

Cosmogenic 11C is produced in-situ by atmospheric muons and forms the main background for the measurement of solar pep- and CNO-neutrinos. However, FLUKA simulations show that the majority of 11C is accompanied by a free neutron in the final state, thus allowing for an efficient tagging method, the so-called Three-Fold Coincidence technique. The technique and its first applications on Borexino data are presented. [ABSTRACT FROM AUTHOR]