The paper presents the results of studies of the spectral properties of a photosensitizer based on indotricarbocyanine dye when accumulating in tissues of experimental animals. Using laser fluorescence spectroscopy, the in vivo and ex vivo fluorescence spectra of tissue-localized indotricarbocyanine dye were obtained for different time counts after intravenous administration. The profile of the pharmacokinetics of its accumulation and withdrawal was determined from the change in the intensity of fluorescence in the tumor and healthy muscle tissues of the photosensitizer. A monotonic deformation of its fluorescence spectrum was revealed in the tissues of tumor nodes and muscles of the thigh when registered through the skin over time after intravenous administration. The achievement of the maximum accumulation of the photosensitizer in the tumor correlates with the stabilization of the shape of its in vivo fluorescence spectrum. Thus, the maximum shift can be used as a diagnostic indicator of the maximum accumulation of indotricarbocyanine photosensitizer in the tumor tissues. The results were confirmed for two groups of animals: the first one – black mice of the C57Bl/6 line with an inoculated tumor of Clone M3 melanoma, the second – white mice of the ICR line with an inoculated tumor of Ehrlich ascites carcinoma. The analysis of the shape of the fluorescence spectrum of the photosensitizer during registration through the skin for animals with different colors has been carried out.

Assessment of the parameters of skin microcirculation is an urgent and important task of modern medicine in the development of methods for diagnosing diseases of the nervous system. The system for assessing the functional state of blood flow in the skin surface layers in the wavelength range from 400 to 850 nm has been improved based on the use of an extended mathematical model of the propagation of optical radiation in human skin by taking into account additional parameters: optical anisotropy of the skin, diameter and shape of erythrocytes in the dermis layer, blood pressure in the brachial artery in the range from 90/60 to 195/130 mm·Hg, plasma protein concentration in the blood (α1, α2, β1, β2, γ-globulins and fibrinogen, g/l), rheological properties of blood flow with a diameter of blood vessels from 4.5 to 500 microns in the skin surface layers, skin temperature from +35 to +41 °C. The developed system makes it possible to determine the severity of microhemodynamic shifts in relation to metabolic disorders, improve diagnosis and evaluate the treatment efficacy of a number of neurological disorders; it also made it possible to reduce the patient examination time and increase the accuracy of measuring the blood flow microcirculation parameters by 10 % (linear and volumetric blood flow velocities) to detect blood flow disturbances in the surface layers of the skin in the normal and abnormal condition of the nervous system.

Analysis of breast cancer whole-slide image is an extremely labor-intensive process. Histological whole slide images have the following features: a high degree of tissue diversity both in one image and between different images, hierarchy, a large amount of graphic information and different artifacts. In this work, pre-processing of breast cancer whole-slide tissue image was carried out, which included normalization of the color distribution and the image area selection. We reduced the operating time of the other algorithms and excluded areas of breast cancer whole-slide tissue with a background to analyze. Also, an algorithm for finding similar neoplastic regions for semi-automatic selection using various image descriptors has been developed and implemented.

The necessity of early diagnosis of respiratory diseases, especially in the context of the COVID-19 pandemic, by means of pulse oximetric screening and monitoring has been substantiated. The expediency of using portable pulse oximeters by therapists and general practitioners has been shown. The main respiratory diseases accompanied by respiratory failure, which can be detected in time by pulse oximetry, are the chronic obstructive pulmonary disease and the obstructive sleep apnea-hypopnea syndrome. Early detection of these diseases is an important task because of the mild symptoms of these diseases in the early stages, and as a result, the prevalence of late diagnosis. Special attention is given to the pulse oximetry for COVID-19 detection, as this infection is also accompanied by respiratory failure. The use of oxygen concentrators and auto CPAP devices for the treatment of respiratory failure as well as rehabilitation has been argued. The effectiveness of the appointment of long-term oxygen therapy using oxygen concentrators for patients with chronic obstructive pulmonary disease, CPAP therapy using automatic CPAP devices for patients with obstructive sleep apnea-hypopnea syndrome with mandatory pulse oximetry monitoring has been confirmed. The analysis of 120 cases of treatment of moderate and severe COVID-19 cases complicated by the pneumonia has been carried out. The efficiency of the use of oxygen concentrators for supplying oxygen to patients at a flow rate not more than 5 l/min has been proven. It has been found that no more than 10 % of patients needed an oxygen flow rate more than 5 l/min. At the same time, the possibility of using CPAP devices for non-invasive ventilation of lungs using full-face masks has been shown. The expediency of using oxygen concentrators and CPAP devices for the rehabilitation of patients after COVID-19 has been noted.

Biomechanics of motor actions solves the problems of analysis of external motor events - kinematic and dynamic movement parameters. Inertial measurement devices such as gyroscope and accelerometer are used for biomechanical analysis of human movements. The paper describes an algorithm for analysis of kinematic characteristics of the running based on inertial gyro signals. Running is used to estimate the physical performance, endurance, coordination abilities of a person. Gyroscope signals were registered using the TrignoTM Wireless System. For data analysis in the MATLAB, the software for automated evaluation of electromyographic and biomechanical motion patterns was developed. The algorithm allows one to calculate time, spatial and spatial-to-time parameters of motion, symmetry of movements of the left and right limbs, and also stability of repetition of biomechanical movement pattern. The algorithm includes the following stages: 1) adaptive filtering of signals; 2) identification of movement phases; 3) calculation of spatial and time symmetry of left and right limbs; 4) analysis of the repetition stability of biomechanical movement pattern. The proposed algorithm was used to estimate the motor coordination potential of high-skilled athletes in longdistance running. The research made it possible to estimate individual features of work of each group of muscles for each sportsman while performing a test task with stepwisely increasing load on a running track. This approach is a tool to detect asymmetric work of paired muscle groups and of muscle groups with irrational workability. The proposed algorithm for the analysis of running kinematic characteristics can be used to develop new criteria for evaluating the effectiveness of solving a movement problem, as well as to assess the correctness of the movement technique and identify errors that can lead to injuries.

The design of modern devices for extracorporeal magnetotherapy should be preceded by physical and mathematical modeling of all stages of the technology of the effect of magnetic fields on various types of body tissues, taking into account their dielectric properties. This is necessary to create an electromagnetic field with the necessary biotropic parameters. In this work, a mathematical model of the effect of electromagnetic field on biological tissues, such as muscles, skin and adipose tissue, is constructed. The mathematical model takes into account various parameters of biological tissue, such as electrical conductivity and relative dielectric constant. Based on the model, the parameters of the response in biological tissues (the amplitude of the response in the tissue and the maximum value of the current in the tissue) were calculated in the innovative Sim4Life 5.2 platform. To test the mathematical model, a laboratory model was used to measure the electrical characteristics of biological tissue. During the research, experiments were carried out with three biological samples: adipose tissue, muscle tissue and skin. The dependences of the response amplitude in biological samples on the output signal power are plotted. The results obtained characterize the use of the proposed operation algorithm in a complex based on the Sim4Life 5.2 platform and simulation of electromagnetic field with a biological object that is optimal for the creation and examination of technologies and devices for magnetotherapy and inductors of extracorporeal effects of magnetic field. This work will make it possible to familiarize a wider range of different experts with the capabilities of the platform not only for modeling new medical devices, but also for the examination of available and those already applied in healthcare.

Musculoskeletal system disorders is one of the priority directions in dentistry. They can manifest as Kosten's syndrome, snapping jaw, painful dysfunction syndrome, increased tooth abrasion, splits, breaks, pain and spasms in muscles, etc. The study set the following objectives: to develop an algorithm for analyzing the movement pattern of the muscular-articular system by developing an algorithm for recording, analyzing, filtering and processing multichannel electromyograms of the maxillofacial muscles. Analysis of the proposed algorithm for processing multichannel electromyograms showed that 7.2 % of multichannel electromyograms could not be analyzed due to patients' violations of the movement algorithm; 8.7 % of electromyogram checkpoint values were corrected. The group without dysfunctions of the temporomandibular joint is characterized by the prevalence of the relaxation coefficient of the left temporal muscle over the coefficient of the right muscle. The dysfunctioned group has the opposite result. The value of the compression ratio of the temporal muscles exceeding 2.5 is typical for the group with dysfunctions of the temporomandibular joint. The studied groups differ as much as possible when analyzing the relaxation coefficients of the temporal muscles. When analyzing this coefficient, it was possible to truly determine the presence or absence of violations in 50 %, falsely – in 16 % of cases. The coefficient of relaxation of the masticatory muscles made it possible to obtain a true state of 24 %, a false one – in 8 %. We concluded that the compression ratio is less suitable for separating patients with and without dysfunction of the temporomandibular joint.

A significant rise in the mass production of products that contain nanoparticles is of growing concern due to the detection of their toxic effects on living organisms. The standard method for analyzing the toxicity of substances, including nanomaterials, is toxicological testing, which requires the substantial consumption of time and material resources. An alternative approach is to develop models that predict the effect of nanomaterials on biological systems. In both cases, for the detection of nanoparticles an effective electronic complex consisting of a sensor with high sensitivity and a data reception/processing/transmission system is necessary. In recent times, fundamental and applied research activities aimed at the application of heterostructure field-effect transistors – high electron mobility transistors–as a base for such sensors have been undertaken. The purpose of this work is to develop a technique for modeling a sensor for toxic nanoparticles based on the heterostructure field-effect transistor. The object of the research is a gallium nitride high electron mobility transistor device structure. The subject of the research is the electrical characteristics of the transistor obtained in static mode. The calculation results show that the dependence between the concentration of the toxic nanoparticles in the test medium and the polarization charge surface density could serve as a base for modeling the sensor for toxic nanoparticles based on the heterostructure field-effect transistor. The primary advantage of the proposed technique is the use of the scaling parameter intended directly for calibrating the polarization charge density in accordance with the two-dimensional electron gas concentration. The obtained results can be utilized by the electronics industry of the Republic of Belarus for developing the hardware components of gallium nitride high-frequency electronics.

This work aims at the formation of nanocomposites based on graphene and metal oxides (copper-iron, zinc and iron) through ultrasonic interaction (20 kHz) and investigation of their electromagnetic properties by scanning electron microscopy, Raman and absorption spectroscopy, and fluorescence methods. The output of this work implies the development of a single-step ultrasound method to form functional Cu/Fe-, ZnO-and Fe3O4-polyvinyl alcohol nanocomposites, and the ultrasonic conjugation of these nanocomposites with pristine drugs, such as ketorolac and acetylsalicylic acid. We established that formed Cu/Fe-graphene-ketorolac, ZnO-grapheneacetylsalicylic acid and Fe3O4-ketorolac obtain optical and superparamagnetic properties of nanoparticles with improved electromagnetic characteristics due to ultrasonic conjugation. Cu/Fe-graphene-ketorolac nanocomposites are revealed to have a spherical shape (< 100 nm) and acquire improved optoelectronic properties due to copper and iron atoms in the matrix of graphene. It is demonstrated that ZnO-graphene-acetylsalicylic acid nanocomposites obtain properties of fluorescence mainly for electromagnetic interaction with the ZnO phase formed on the surface of graphene. Ultrasonic conjugation of ketorolac with magnetite proved to increase the electron density of Fe3O4-ketorolac that obtains superparamagnetic properties, and its biocompatibility can be improved when coated with polyvinyl alcohol. In general, formed nanocomposites are of great interest in medical electronics and nanomedicine as functional materials with electromagnetic properties being controlled at the molecular and atomic levels. Such nanocomposites can also find application as components in electronic devices for diagnosis and treatment of serious inflammatory disorders. Industries will find the singlestep ultrasound method of special interest because it is eco-friendly and can be scaled up by a versatile spectrum of inorganic and organic materials and drugs.

The method of automatical adjustment controlled maintenance of the surgical stage of anesthesia of patient during general anesthesia by means of volatile anesthetic dosage regulation depending on BIS level is described and explained. There was conducted a theoretical analysis of possibilities and perspectives of anesthesia depth’s automatical adjustment during general anesthesia by bispectral index individual monitoring depending on volatile anesthetic dosage and individual patient’s condition along with extent of surgical intervention. The possibilities of currently available medical devices allowing to implement the method into the practice have been analyzed. The technical explanation of interaction between modern volatile anesthetic vaporizer and bispectral index monitoring by feedback from integrated microprocessor, breathing circuit and multiple gas monitor of anesthesia machine and microprocessor of vaporizer has been presented.

The article presents the results of experimental studies of the wetting angle of the tooth surface after treatment in the plasma of a dielectric barrier discharge at atmospheric pressure. Measurements of the dependence of the length of the plasma torch and the temperature of the treatment object on the flow rate of the working gas have been carried out. Argon was used as a working gas. The research revealed the possibility to change the length of the plasma torch in the range from 9 mm to more than 25 mm and showed that the temperature of the treated tooth surface with an increase in flow rate from 40 degrees Celsius falls to 32 degrees Celsius. The distilled water wetting angle was determined by the lying drop method. Depending on the processing time, a decrease in the contact angle of the tooth surface wetting from the initial 77 to 20 degrees was observed. The modes of operation of the plasma generator in tooth surface treatment, which provide the best indicators of its wettability, have been determined.

Retinal detachment in children often requires multiple revisions. Despite active surgical treatment, subretinal fluid can persist for a long time in the macular region of the fundus. This leads to a decrease in visual acuity after surgery and an unsatisfactory functional result of treatment. In the absence of central vision, children develop amblyopia and secondary strabismus. Reoperations increase the risk of complications. Threshold laser coagulation leads to thermal burns of all layers of the retina with the formation of chorioretinal adhesion, which ensures adhesion of the retinal layers, but irreversibly damages the retinal neuroepithelium. Аs a result, the use of threshold laser coagulation in the macular zone is limited. The method of subthreshold micropulse diode laser ablation (STDLA) was developed on the basis of a clinical examination of 44 pediatric patients of the pediatric ophthalmology department of the Minsk Regional Children's Clinical Hospital, whose level of subretinal fluid in the posterior pole of the eyes remained for a long time after extrascleral surgery for retinal detachment. The proposed exposure parameters provide a selective effect on the cells of the retinal pigment epithelium with laser radiation in the micropulse mode without irreversible thermal denaturation of photoreceptors and without damage to the neuroepithelium in order to stimulate the resorption of subretinal fluid and correct transudative disorders. As a result, the adhesion of the retinal photoreceptor layer to the pigment epithelium is restored. The effectiveness of the method is confirmed by a decrease or complete disappearance of subretinal fluid, adhesion of neuroepithelium according to optical coherence tomography and leads to an increase in visual acuity. The proposed method made it possible to optimize the treatment of children with retinal detachment, to improve the anatomical and functional outcomes of treatment, which is of medical and socio-economic importance.

The study of the erosion activity of cavitation is of considerable interest for clarifying the mechanism of the effect of cavitation on biological tissues and cells. This paper proposes an improved technique for assessing the erosion activity of acoustic cavitation. The results of testing this technique in relation to the problem of studying the distribution of erosion activity in the cavitation region, generated by a radiator with a rod waveguide, are presented. The experiments were carried out using a submersible emitter with a resonant frequency of 32 kHz. It was found that erosion activity rapidly decreases with distance from the emitter and depends on the distance to the emitter L as 1/L3 when the diameter of the emitter is less than or of the order of the wavelength in the used liquid. It was shown that there is a correlation between the erosion activity of cavitation and the readings of the cavitometer with the output signal being the integral intensity of the highfrequency component of the cavitation noise in the frequency range up to 10 MHz. Piezoelectric sensors were used to register cavitation noise. In particular, in liquids characterized by a higher level of erosion activity, the output signal of the cavitometer is also higher. In this case, the readings of the cavitometer change depending on the distance to the radiator as 1/L. Based on the data obtained, a method is proposed for assessing the erosion activity of cavitation by the magnitude of the intensity of cavitation noise in a cube. It is shown that this parameter is linearly related to the results of measurements of the erosional activity of cavitation. The results obtained will be used in the development of a specialized cavitometer designed to assess the erosion activity of cavitation during in vitro studies of the effect of ultrasound on cells.