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AIM: to study the cytokine link of immunity in patients with the new coronavirus infection COVID-19 and the possibility of using these data to predict the risk of lung tissue damage. MATERIALS AND METHODS: Patients with diagnosed new coronavirus infection COVID-19 were divided into 4 groups depending on the severity of the disease: 1 asymptomatic patients; 2 patients with lung tissue damage in the amount of 25%; 3 patients with lung tissue damage 50%; 4 patients with lung tissue damage 75% (according to the results computed tomography). Immunological studies were performed upon admission to the clinic, then after 7 days and before discharge. The concentration of cytokines in blood serum was studied by the method of solid-phase enzyme immunoassay using kits manufactured by Vector Best. RESULTS: In all groups, a low content of proinflammatory cytokines was found: tumor necrosis factor and interferon-, interleukin-1, interleukin-2. The median level of interleukin-6 in all groups during the entire follow-up period was within the normal range, however, in some patients there was a multiple excess of its concentration. In groups with 50% and 75% lung tissue damage, an increase in the concentration of interleukin-8 was shown. Statistically significant differences were noted only for the level of interleukin-8 between the group with an asymptomatic form of infection and the CT-2 and CT-3 groups. It was found that the concentration of interleukin-1 below 3.58 pg/ml is a significant risk factor for severe disease. In all groups of subjects, low levels of interleukin-4 and interleukin-10 were noted, while there was no significant difference between the groups. Positive correlations were revealed between the degree of lung tissue damage and the level of interleukins 6, 2 and 8. Negative correlations were established between the degree of lung tissue damage and the content of interleukin-1. CONCLUSION: There was no significant activation of the cytokine link of adaptive antiviral immunity in the examined contingent. Serum cytokine levels were within normal values and had no significant intergroup differences. An increase in IL-8 in groups with clinically pronounced signs of infection indicates the activation of indicators characterizing innate immunity.

The article proposes a new technique for estimating the instantaneous supply in gear hydraulic machines. It takes into account the peculiarity of the movement of the radius connecting the centers of rotation of the gears with the point of engagement. The dependence of the angular velocity of rotation and the length of the radius on the position of the engagement point due to slipping of the working profiles of the gear teeth are determined. Estimation of the degree of non-uniformity of the supply, in accordance with the obtained model, differs significantly from the traditional ideas about the pulsation of the instantaneous supply in gear hydraulic machines.

An analytical method for calculation of local stresses in double-sided butt welded joints at misalignment of welds’ axes is developed. The method is applicable for welded thin-gauge plates with different geometry of welds on the face and root sides under tensile load. In the given calculation example, it was shown that the stresses reach their maximum value in the zone of transition from the root weld to the base metal which is farther from the axis of the face weld. The results of analytical calculations are in good agreement with the results obtained using the finite element method.

Aim. To study the perioperative dynamics of myocardial injury biomarkers high-sensitivity cardiac troponin I (hs-cTnI), ischemia-modified albumin (IMA) and soluble ST2 (sST2) when taking nicorandil in lung cancer patients with concomitant coronary heart disease (CHD) undergoing surgical lung resection.Material and methods. The study included 54 patients (11 women and 43 men) with non-small cell lung cancer and concomitant stable CHD who underwent lung resection in the volume of lobectomy or pneumonectomy. Patients were randomly assigned to the nicorandil group (oral administration 10 mg BID for 7 days before and 3 days after surgery; n=27) and the control group (n=27). In the study groups, the perioperative dynamics of hscTnI, IMA and sST2, determined in the blood before and 24 and 48h after surgery, were compared. We calculated the incidence of acute myocardial injury in the groups, which was diagnosed in cases of postoperative hs-cTnI increase of more than one 99th percentile of the upper reference limit. The associations of nicorandil intake and acute myocardial injury were evaluated.Results. The groups were comparable in gender, age, basic clinical characteristics, as well as baseline levels of myocardial injury biomarkers. After the intervention, both samples showed an increase in the hs-cTnI and sST2 levels and a decrease in IMA concentration (all p2=0.027). The adjusted odds ratio of acute myocardial injury when taking nicorandil was 0.35 (95% confidence interval 0.15-0.83, p=0.017).Conclusion. Taking nicorandil in patients with lung cancer and concomitant CHD who underwent surgical lung resection is associated with a lower postoperative increase in hs-cTnI and sST2 and a reduced risk of acute myocardial injury, which may indicate the cardioprotective effect of nicorandil under acute surgical stress conditions.

It is known that during operation, the aircraft construction materials are exposed to significant mechanical loads and changes in temperature for a very short period of time. All this leads to various defects and damages in the aircraft assemblies and units that need to be inspected for the safe operation of the aircraft, their assemblies, and units. In some cases, the implementation of inspection or diagnostic is accompanied by the emergence of technical difficulties caused by the large size of the aircraft assemblies or units and limited access to their local places. Under such conditions, ensuring the possibility of diagnosis in hard-to-reach places of the object becomes especially important. The problem can be solved by applying wireless technologies. It allows spatial separation of the probes and the signal processing units, which simplifies the scanning of the surfaces of the large assemblies and units in hard-to-reach places. In this article, the description of the developed wireless system of eddy current inspection for aircraft structural materials is given. Experimental results of object scanning are given in the form of a distribution of the values of probe signal informative parameters (amplitude, frequency and decrement) along the object coordinates.

BACKGROUND. There is enough evidence of the negative impact of excess weight on the formation and progression of res piratory pathology. Given the continuing SARS-CoV-2 pandemic, it is relevant to determine the relationship between body mass index (BMI) and the clinical features of the novel coronavirus infection (NCI).AIM. To study the effect of BMI on the course of the acute SARS-COV-2 infection and the post-covid period.MATERIALS AND METHODS. AKTIV and AKTIV 2 are multicenter non-interventional real-world registers. The АКТИВ registry (n=6396) includes non-overlapping outpatient and inpatient arms with 6 visits in each. The АКТИВ 2 registry (n=2968) collected the data of hospitalized patients and included 3 visits. All subjects were divided into 3 groups: not overweight (n=2139), overweight (n=2931) and obese (n=2666).RESULTS. A higher BMI was significantly associated with a more severe course of the infection in the form of acute kidney injury (p=0.018), cytokine storm (pCONCLUSION. Overweight and/or obesity is a significant risk factor for severe course of the new coronavirus infection and the associated cardiovascular and kidney damage Overweight people and patients with the 1st and 2nd degree obesity tend to have a high risk of death of SARS-CoV-2 infection in both acute and post-covid periods. On top of that, in case of morbid obesity patients this tendency is statistically significant. Normalization of body weight is a strategic objective of modern medicine and can contribute to prevention of respiratory conditions, severe course and complications of the new coronavirus infection.

Computational material science aims to simulate substances to understand their physical properties. Bioelectronics is an interdisciplinary field that studies biological material from the conductivity point of view. In case of proteins, the folding is an important feature that directly influences physical and chemical properties. The folding modelling is a hard task. The enormous number of degrees of freedom makes modelling impossible for classical computation due to resource limits. Quantum computations aim to process multidimensional data with logarithmic growth of quantum bits. Quantum operators (gates) form quantum programs, known as circuits that process the input data. In real quantum computers, the gates are noisy and expensive to execute. Thus, it is essential to reduce the number of quantum gates both for the quality of the result and the cost of computations. This work describes an approach to decrease the number of quantum gates based on their mathematical property. The matrix properties form the first optimization technique. In this case, the optimized quantum circuit predicts precisely the same protein folding as the not optimized circuit predicts. This happens because both of the circuits are mathematically equivalent. The removal of weakly-parametrized gates forms the second optimization technique. In such case the optimized quantum circuit calculates the approximate protein folding. The error depends on parameter’s amplitude of the gates. The first technique allows to decrease the circuit depth from 631 to 629 gates while modelling the part of Azurin peptide. The second technique allows to decrease the depth to 314 gates with the threshold parameter value 0.4 radians.

Bronchial asthma is a serious public health issue. It is important to reduce the frequency of attacks for BA patients. Vaccination for pneumococcal infection is an important complementary tool that can improve the clinical pattern of bronchial asthma. The study involved 102 patients with bronchial asthma, who were monitored over 4 years. The patients were divided into 4 groups based on the vaccination scheme used for pneumococcal infection: PCV13, PPV23, PPV23/PCV13, PCV13/PPV23. Sequential vaccination with pneumococcal conjugate and polysaccharide vaccines leads to a decrease in the isolation of pneumococcus from sputum in BA patients, which has a pronounced positive effect on the clinical pattern of this disease, namely, it leads to a decrease in the frequency of attacks, the requirement for courses of antibacterial chemotherapy and hospitalizations, and therefore this vaccination protocol should be included in the standards of BA patient management.

Modern trends in the optimal and rational design of technical objects cross a large number of directions of their implementation. One of the interesting and promising directions is genetic and evolutionary algorithms (GА and EA). Authors promote the use of GА and EA as a tool for solving problems of optimal and rational design of complex mechanical systems. The relevance of highlighting modern methods, approaches and strategies for the implementation of GА and EA is described, as well as consideration of their applied implementation, which makes it possible to identify interesting directions of research that, with further adaptation or modifications, can be used to solve the problems of optimal and rational design of gearboxes, boxes gears and transmissions. The main general directions of the literature on GА and EA are highlighted, as well as the practical use of GА and EA in: technical and technological activities, physics, construction, water systems, nanotechnologies, analytical and simulation modeling, electrical and electronic systems, modeling of artificial intelligence and neural networks, information technologies, economic theory, administration and management, marketing, sociology, biology and medicine. This made it possible to understand the course of scientific thought on this issue, to determine the advantages and disadvantages of existing directions and approaches, and helped to choose the vector of further scientific thought, to decide on interesting approaches, strategies and methods. Considering certain features of EA, the authors prefer them. And in terms of strategies, hybridization with other methods, maximum saturation of all stages with "randomness" and the possibility of learning (memory organization) of the algorithm similar to neural networks are promising. Keywords: optimal design, research directions, genetic algorithms, evolutionary algorithms

Reducing the mass and dimensions of involute spur gears is an actual task of modern mechanical engineering. One of the perspective ways to solve it is the use of gearing with an increased working tooth depth and profile contact ratio εα ≥ 2. The study is devoted to the development of optimal design methods for such gears. Optimality criteria is formulated as follows: the contact stresses in the pitch point must take a minimum value when all constructive, geometric, kinematic, and technological constraints are met, first, when the profile contact ratio εα ≥ 2 is ensured. Variables planning are defined. These are addendum coefficients of the basic racks tooth for pinion and wheel , ; profile angle of the basic rack α; addendum modification coefficient of the pinion x1. Formed a system of constraints for the variables planning: the main functional constraint of the minimum value of the profile contact ratio: εα ≥ 2; constraint for the addendum coefficients of the basic racks tooth for pinion and wheel , ; constraint for profile angle of the basic rack α; constraint for addendum modification coefficients x1, x2; absence of the cutter interference for tooth dedendum; absence of the sharpening for tooth addendum; absence of the mesh interference; ensuring the bending strength of pinion and wheel teeth. A method for solving the problem of optimal design is chosen. The method of probing the space of design parameters was chosen from all the variety. The points of the LPτ-sequence are used as test points. The method allows you to operate with a significant number of parameters – up to 51, provides a sufficiently large number of evenly distributed test points – up to 220. In further studies, it is planned developing of methods and algorithms for solving the problem. Also carry out test and verification calculations to confirm and evaluate the theoretical results. Keywords: spur gear, profile contact ratio, contact stress, optimal design, objective function, variables planning, constraints of the variables planning.

Mixtures of carbon nanotubes (CNTs) and graphene oxide (GO) in composite materials often exhibit synergistic effects with respect to mechanical and electrophysical properties. In this paper, the mechanisms of interaction between CNTs, GO and epoxydian resin macromolecules were discussed based on the results of molecular dynamics simulations. Calculations were performed in the MM3 force field at exposure times up to 100 ps. The influence of the CNT’s graphene layers shape and the presence of oxygen-containing functional groups on the self-assembly process during the epoxy composite formation has been demonstrated. It is shown that graphene oxide sheets are arranged around cylindrical nanotubes and envelop them, while when using tapered nanotubes, the formation of alternating layers of CNTs and GO should be expected. The presence of oxygen-containing groups on the surface of cylindrical nanotubes promotes the penetration of epoxydian resin macromolecules into the space between CNTs and GO. The simulation results of the "cylindrical CNTs - GO" and the "conical CNTs - GO" hybrid particles were confirmed by scanning electron microscopy data.

Исследуются неравенства Маркова-Бернштейна (между нормами функции и ее производных) для полиномов по системе экспонент с комплексными показателями. Установлена связь между точными константами в этих неравенствах и задачей об устойчивости линейных динамических систем с переключениями. В частности, получены оценки максимального шага дискретизации системы. Доказана монотонная зависимость наилучших констант от показателей экспонент в случае, когда эти показатели действительны. Это дает асимптотически точные равномерные оценки и общий вид экстремального полинома. Случай комплексных показателей оставлен в виде открытой проблемы.

In the introduction, the properties of fluff of cattail cobs are considered, including when used as an oil sorbent. Taking into account that the sorbent can usually be stored in warehouses until it is used for several years, it is necessary to ensure the safety of its properties, including from damage by microorganisms. To achieve a moisture content of 0.11 kgmoisture/kgdry.mat, at which the development of microorganisms is suspended, it is necessary to dry cattail fluff. Since this material, fluff of cattail cobs, has not been used on an industrial scale (only on a handicraft scale), there are no regularities in its drying in the literary sources. Therefore, the purpose of this work was to clarify some drying parameters, namely, to find the optimal height of the cattail fluff layer in the dryer, which provides the minimum time to reach equilibrium moisture, as well as the kinetic parameters of the drying process. To establish the kinetic parameters of drying and the optimal layer height when loading into the drying chamber, a laboratory dryer was developed, manufactured and used in these studies. The main part describes the installation scheme for studying the kinetics of drying cattail fluff by the weight method and shows the procedure for performing measurements: conditions and sequence of operations. In the ʻʻResults and Discussionʼʼ section, the drying curves obtained during the study and the drying rate curves for different heights of the down layer are given. Based on these data, the mathematical processing of the results was carried out to obtain an equation that makes it possible to calculate the height of the loading layer of the material to be dried and the time required to achieve the required moisture content. The relationship between layer height and drying time is non-linear, increasing the height of the down layer by 2 times leads to an increase in drying time by 4 times and reduces the maximum drying speed by 3 times.

A mathematical model of profile shifted quasi-involute arc-tooth-trace gears is obtained. The model includes functional relationships between the geometric-kinematic meshing characteristics and parameters of the generating surface as well as conditions which allow to prevent teeth undercutting and tip pointing. A short analysis of meshing characteristics value along the tooth trace is done for pressure angle value of 20º. This value of the angle was chosen as it is the most common one for general-duty gears, although the basic rack profile angle in the model is a variable quantity. The model can be used in the design and analysis of geometric-kinematic meshing characteristics of profile shifted quasi-involute arc-tooth-trace gears, cut by Gleason-type cutters with different profile angle value.

The structure of steering gear’s HATLAPA mechanism is analyzed. It is shown that presence of redundant constraints in it increases laboriousness of gear montage and respectively worsen maintainability. On the basis of provided analysis developed mechanism with reduced more than twice redundant constrainsts number.

Computer-aided analysis by the method of finite elements of the stress-strain working state of rollers having a pair point contact, a support-rotating device of truck cranes and other lifting-transport machines is performed. The regularities of the change of contact stresses with characteristic values at the ends of the rollers and along their length, which are important for practice, are obtained. The obtained results are presented graphically, which increases the possibilities of their practical use at the stages of design and operation of support-rotating devices of truck cranes with mutually perpendicular rollers.

This paper presents methods and approaches that can be used for production of Sm-Co-Fe-Cu-Zr permanent magnets with working temperatures of up to 550 °C. It is shown that the content of Sm, Cu, and Fe significantly affects the coercivity (Hc) value at high operating temperatures. A decrease in the content of Fe, which replaces Co, and an increase in the content of Sm in Sm-Co-Fe-Cu-Zr alloys lead to a decrease in Hc value at room temperature, but significantly increase Hc at temperatures of about 500 °C. Increasing the Cu concentration enhances the Hc values at all operating temperatures. From analysis of the dependence of temperature coefficients of the coercivity on the concentrations of various constituent elements in this alloy, the optimum chemical composition that qualifies for high-temperature permanent magnet (HTPM) application were determined. 3D atom probe tomography analysis shows that the nanostructure of the HTPM is characterized by the formation of Sm2(Co,Fe)17 (2:17) cells relatively smaller in size along with the slightly thickened Sm(Co,Cu)5 (1:5) boundary phase compared to those of the high-energy permanent magnet compositions. An inhomogeneous distribution of Cu was also noticed in the 1:5 phase. At the boundary between 1:5 and 2:17 phases, an interface with lowered anisotropy constants has developed, which could be the reason for the observed high coercivity values.

Annotatsiya: Umumiy o‘rta ta’lim maktablarida o‘quvchi yoshlarda mustaqil dastur tuzish ko‘nikmalarini shakllantirish, dasturlash tillariga qiziqtirish, ularni kelajakda o‘z o‘rinini topishiga va mamlakat rivoji uchun mukammal dasturlar yaratishiga turtki bo‘ladi.&nbsp

A mathematical model of energy metabolism in erythrocyte-bioreactors loaded with alcohol dehydrogenase and acetaldehyde dehydrogenase was constructed and analyzed. Such erythrocytes can convert ethanol to acetate using intracellular NAD and can therefore be used to treat alcohol intoxication. Analysis of the model revealed that the rate of ethanol consumption by the erythrocyte-bioreactors increases proportionally to the activity of incorporated ethanol-consuming enzymes until their activity reaches a specific threshold level. When the ethanol-consuming enzyme activity exceeds this threshold, the steady state in the model becomes unstable and the model switches to an oscillation mode caused by the competition between glyceraldehyde phosphate dehydrogenase and ethanol-consuming enzymes for NAD. The amplitude and period of metabolite oscillations first increase with the increase in the activity of the encapsulated enzymes. A further increase in these activities leads to a loss of the glycolysis steady state, and a permanent accumulation of glycolytic intermediates. The oscillation mode and the loss of the steady state can lead to the osmotic destruction of erythrocyte-bioreactors due to an accumulation of intracellular metabolites. Our results demonstrate that the interaction of enzymes encapsulated in erythrocyte-bioreactors with erythrocyte metabolism should be taken into account in order to achieve the optimal efficacy of these bioreactors.

Ushbu maqolada scratch dasturlash muhitida tarmoqlanuvchi bloklar bilan ishlash hamda tarmoqlanuvchi bloklarga doir turli dasturlar tuzish metodikasi yoritib berilgan.

Aim. To study the perioperative dynamics of myocardial injury biomarkers and determine their significance in assessing the postoperative mortality risk in patients with nonsmall cell lung cancer.Methods. The study included 82 male patients with non-small cell lung cancer undergoing pneumonectomy. The median age was 64 (59; 67) years. The blood levels of cardiac troponin I (cTnI), N-terminal pro b-type natriuretic peptide (NT-proBNP) and fatty acid-binding protein (FABP) were noted before and after surgery. The rate of myocardial injury after non-cardiac surgery (MINS) was determined. The postoperative cTnI level above 0.023 μg/L was considered as MINS criterion. The significance of the studied biomarkers in predicting the total mortality within 6 months after surgery was assessed using the univariate and multivariate Cox regression and ROC analysis.Results. Compared to baseline levels, all myocardial injury biomarkers increased in 24 and 48h after surgery: cTnI by 120 and 85%, NT-proBNP by 128 and 129%, FABP by 207 and 31%, respectively. The postoperative cTnI levels met the MINS criterion in 45.1% of patients. During the follow-up period 12 patients died, 9 (75%) of those were diagnosed with MINS. Based on the results of the univariate Cox regression overall postoperative mortality was associated with NTproBNP levels before and after the surgery, cTnI growth rate after the surgery and MINS. According to the multivariate Cox regression (adjusted for age and other clinical parameters), preoperative NT-proBNP and atrial fibrillation proved to be the independent predictors of postoperative mortality. The cut-off value of preoperative NT-proBNP was 225 pg/mL; relative risk of death above that value was 5.9 and 95% confidence interval of 1.74–20.0.Conclusion. In patients with non-small cell lung cancer the increase of cTnI, NT-proBNP and FABP mean levels was observed in 24 and 48 hours after pneumonectomy. MINS was diagnosed in 45.1% of patients. According to the univariate regression analysis, MINS and preoperative and postoperative NT-proBNP levels were associated with the risk of total six-month postoperative mortality. The preoperative NT-proBNP was proved to be an independent predictor of adverse outcome.

Scattered waves are used to construct diffraction seismic images. There are various algorithms for their extraction, which can be divided into three classes regarding the data processing steps: data domain procedures, migration-based methods, and image processing. The presented paper provides an investigation of the influence of the data domain extraction of scattered waves on the migration procedure based on the construction of selective images. Numerical experiments were performed using synthetic data got for a realistic model with fractures for the field in Eastern Siberia.

This study considers the Full Waveform Inversion (FWI) method based on the asymptotic solution of the Helmholtz equation. We provide frequency-dependent ray tracing to get the wavefield used to compute the FWI gradient and calculate the modelled data. With a comparable quality of the inverse problem solution as applied to the standard finite-difference approach, the speed of calculations in the asymptotic method is an order of magnitude higher. A series of numerical experiments demonstrate the approach's effectiveness in reconstructing the macro velocity structure of complex media for low frequencies.

The paper studies the influence of the scattered component of the wavefield on the full waveform inversion results. For different scenarios, the contribution of scattered waves was investigated. Utilizing the one step of the quasi-Newton FWI method, we demonstrate that scattered wavefields bring helpful information in the context of the solution of the inverse dynamical problem.

The work is devoted to the development and study of a statistical model of a discrete network of cracks at different spatial scales. The distribution of fracture centers is a fractal set, which is determined by a given value of the correlation fractal dimension D 2 . The fracture lengths are described by a power-law probability distribution with the corresponding value of the exponent α . The possibility to estimate these model parameters based on the corresponding seismic images is investigated.

A comparison of two closely located reservoirs on the Southern Bug River and its tributary in the southern region of Ukraine is carried out. One of them (Tashlyk reservoir on a small river, tributary of the Southern Bug River) is a cooling reservoir (pond) for the nuclear power plant, the other (Alexandrovskoye reservoir, on the Southern Bug River) is used for agricultural purposes, for the production of electricity at a hydroelectric power plant, and as a lower reservoir for a pumped storage power plant. Comparison of the main indicators of phytoplankton in the reservoirs was carried out together with its spatial distribution. It was found that the distribution of coenotic groups of plankton in the cooling reservoir corresponds to thermal conditions. In the Alexandrovskoye reservoir, separate communities of plankton are formed along its length. The description of indicator species of algae in two reservoirs is given. The important role of the catchment basin was demonstrated with statistical maps. It was shown that a significant increase in temperature in the cooling pond did not lead to the depletion of phytoplankton.

Liquid ring vacuum pumps and compressors are mechanical positive displacement turbomachines that can operate in the mode of both vacuum compressor and vacuum pump. They are widely used in the fields of filtration, cryogenic, reaction, gas injection, condensation, evaporation, and convective drying. Despite their low performance, they have many advantages such as low costs, simplicity, reliability, improve suction characteristics, and in many cases, can provide a more efficient option. Improving efficiency is the key to decrease energy consumption and costs. The article analyzed and evaluated the previous investigations regarding these machines with a focus on challenges of improving efficiency, advances in numerical simulation, and experiments to afford beneficial insight on future research and next steps. The study revealed that the thermal interaction and the cavitation phenomenon are among the most important problems that require further research.

Annotation: Diabetes insipidus is a disease characterized by the inability of the kidneys to reabsorb water and concentrate urine. According to the classification, there are three main types of diabetes insipidus: central, nephrogenic, primary polydipsia. Other rarer types of diabetes insipidus should also be remembered: gestational, functional (pediatric), iatrogenic. The pathogenesis of central diabetes insipidus is associated with impaired secretion or action of vasopressin on V2 receptors.

An analytical method for determination of a stress condition of butt welded thin-gauge plates with asymmetrical reinforcement is developed. The proposed method allows take into account the effect of the load application eccentricity on the tensile stress concentration factor (SCF) in the weld root zone. It is presented that the bending stresses, caused by this eccentricity, result in increasing the total stresses up to 75%. The results of analytical SCF calculations are in good agreement with the results obtained using the finite element method.

Solving the problem of optimization for transmission load-carrier/prime mover MT-LB improves the mass characteristics of the machine. Mathematical model of optimization was constructed, namely: optimization objective function was built; variables planning are defined; a system of constraints was constructed. The solution is based on probing the parameter space, where points of the LPτ-sequence are used as test points in a single multidimensional cube. Also, the algorithm for optimal design of the transmission has been developed.

Seismic inversion is used in practice as a tool for predicting reservoir properties. It allows one to extract a model with a high level of detail from seismic data, i.e., high-frequency component of the model. In this case, the input data are the time processing results, and the issues related to the low-frequency component of the model are not considered usually. In the presented work, a model-based seismic inversion algorithm is implemented. The input data for the inversion are the depth image results in true amplitudes and the depth migration velocity model. The possibilities of seismic inversion are numerically investigated to refine the low-frequency component of the model. Experiments were carried out using synthetic seismic data got for realistic Sigsbee model.

В работе международного научного семинара, состоявшегося 19 апреля 2023 г. на Экономическом факультете Санкт-Петербургского государственного университета приняло участие более 60 человек. Зарубежные участники, докладчики и слушатели из других городов имели возможность принять участие в работе форума в режиме онлайн.

Artificial neural networks are currently applied in a wide variety of fields, and they are near to achieving performance similar to humans in many tasks. Nevertheless, they are vulnerable to adversarial attacks in the form of a small intentionally designed perturbation, which could lead to misclassifications, making these models unusable, especially in applications where security is critical. The best defense against these attacks, so far, is adversarial training (AT), which improves the model’s robustness by augmenting the training data with adversarial examples. In this work, we show that the performance of AT can be further improved by employing the neighborhood of each adversarial example in the latent space to make additional targeted augmentations to the training data. More specifically, we propose a robust selective data augmentation (RSDA) approach to enhance the performance of AT. RSDA complements AT by inspecting the quality of the data from a robustness perspective and performing data transformation operations on specific neighboring samples of each adversarial sample in the latent space. We evaluate RSDA on MNIST and CIFAR-10 datasets with multiple adversarial attacks. Our experiments show that RSDA gives significantly better results than just AT on both adversarial and clean samples.

A mathematical model of energy metabolism in erythrocyte-bioreactors loaded with alcohol dehydrogenase and acetaldehyde dehydrogenase was constructed and analyzed. Such erythrocytes can convert ethanol to acetate using intracellular NAD and, thus, can be used to treat an alcohol intoxication. Analysis of the model reveals that the rate of ethanol consumption by the erythrocyte-bioreactors increases proportionally to activity of incorporated ethanol-consuming enzymes until their activity reaches a specific threshold level. When the ethanol-consuming enzyme activity exceeds this threshold, the steady state in the model becomes unstable and the model switches to an oscillation mode caused by a competition of glyceraldehyde phosphate dehydrogenase and ethanol-consuming enzymes for NAD. An amplitude and period of metabolite oscillations first increase with the increase in the activity of e encapsulated enzymes. A further increase in these activities leads to a loss of the glycolysis steady state, and a permanent accumulation of glycolytic intermediates. The oscillation mode and the loss of the steady state can lead to osmotic destruction of erythrocyte-bioreactors due to an accumulation of intracellular metabolites. Our results demonstrate that the interaction of enzymes encapsulated into erythrocyte-bioreactors with erythrocyte metabolism should be taken into account in order to obtain an optimal efficacy of these bioreactors.

Chemical pesticides, while playing an important role in the suppression of insect pests, should be used in a manner that minimizes negative effects on natural enemies. The parasitoid, Anagyrus vladimiri Triapitsyn (Hymenoptera: Encyrtidae), plays an important role in the management of mealybug pests of citrus groves in the Mediterranean region. This study was conducted to evaluate the effect of commonly used acaricides (Spirodiclofen, Spirotetramat, Sulfur, Fenpyroximate, Abamectin) and mineral oils (Levanola, EOS, JMS, and Ultrapaz) on acute mortality of A. vladimiri. Toxicity was assessed in 4 cases: (i) direct spray application on adults, (ii) pesticide application on the mummified host, (iii) feeding with contaminated food, and (iv) contact with pesticide residue. The pesticide Abamectin, applied alone and with Levanola oil was highly toxic to adults in all bioassays, with the exception of direct spray application on the mummified host. Fenpyroximate was found to be highly toxic only when sprayed directly on adults, and sulfur was slightly harmful. Mineral oils were harmful when ingested with food; otherwise, they did not cause appreciable adult mortality. The findings of the present study suggest that all tested materials, with the exception of Abamectin and Fenpyroximate, are compatible with the survival of A. vladimiri. Direct ingestion of oils can, however, cause a degree of mortality. Given that indiscriminate use of these pesticides may affect the population ecology of A. vladimiri, they should be used with caution.

In this paper we consider a method for calculating frequency-dependent rays, which allows to approximate effectively the propagation of a broadband signal. A comparative analysis of this method with the standard ray method and the finite-difference method is carried out. It is shown to be promising for solving seismic problems.

In this paper we consider a method for calculating frequency-dependent rays, which allows to approximate effectively the propagation of a broadband signal. A comparative analysis of this method with the standard ray method and the finite-difference method is carried out. It is shown to be promising for solving seismic problems.