Current Source Research Articles

Localized estimation of event-related neural source activity from simultaneous MEG-EEG with a recurrent neural network

Estimating intracranial current sources underlying the electromagnetic signals observed from extracranial sensors is a perennial challenge in non-invasive neuroimaging. Established solutions to this inverse problem treat time samples independently without considering the temporal dynamics of event-related brain processes.This paper describes current source estimation from simultaneously recorded magneto- and electro-encephalography (MEEG) using a recurrent neural network (RNN) that learns sequential relationships from neural data. The RNN was trained in two phases: (1) pre-training and (2) transfer learning with L1 regularization applied to the source estimation layer. Performance of using scaled labels derived from MEEG, magnetoencephalography (MEG), or electroencephalography (EEG) were compared, as were results from volumetric source space with free dipole orientation and surface source space with fixed dipole orientation. Exact low-resolution electromagnetic tomography (eLORETA) and mixed-norm L1/L2 (MxNE) source estimation methods were also applied to these data for comparison with the RNN method.The RNN approach outperformed other methods in terms of output signal-to-noise ratio, correlation and mean-squared error metrics evaluated against reference event-related field (ERF) and event-related potential (ERP) waveforms. Using MEEG labels with fixed-orientation surface sources produced the most consistent estimates.To estimate sources of ERF and ERP waveforms, the RNN generates temporal dynamics within its internal computational units, driven by sequential structure in neural data used as training labels. It thus provides a data-driven model of computational transformations from psychophysiological events into corresponding event-related neural signals, which is unique among MEEG source reconstruction solutions.

Changes in the Interpretation of the Criminal Law by the Supreme Court of the Russian Federation: Factors, Consequences, Risks

Problem statement. The problems of the evolutionary interpretation of the criminal law in the scientific literature are practically not given attention. At the same time, the practice of significantly correcting the interpretative positions of the Supreme Court of the Russian Federation forces us to conceptualize this problem as an independent object of scientific analysis. Aims and objectives of the research. The purpose of the work is to develop the theory of interpretation of the criminal law by analyzing the factors influencing the change in the position of the highest court on the interpretation of the criminal law, as well as by investigating the mechanisms necessary to deter dynamic interpretation. Methods. The work is based primarily on the use of a documentary method of researching materials of judicial practice and a critical analysis of scientific literature. Results. Based on the study of the materials of the practice of the Constitutional Court of the Russian Federation, practice-forming documents of the Supreme Court of the Russian Federation, current judicial practice and scientific sources, the following are presented: (a) factors influencing the dynamics of the position of the Supreme Court of the Russian Federation on the interpretation of criminal law; (b) factors allowing to predict changes in the dynamics of the legal position; (c) risks arising in connection with changes in acts of interpretation. Brief conclusions. The dynamics of the legal interpretation positions of the Supreme Court of the Russian Federation is influenced by at least four groups of factors: the constitutional and legal meaning of criminal law regulations identified by the Constitutional Court of the Russian Federation; changes in the socio-political course implemented in the country; the needs of law enforcement practice changing under the influence of new criminal challenges; the development of scientific ideas about the content of criminal law. These factors, acting individually or together, may determine a change in the approach of the highest court to understanding the criminal law. However, such changes, no matter how necessary they are, must have an important quality of predictability so that the dynamics of the interpretation of the law does not undermine the beginning of stability of criminal law regulation. The risks of instability of legal regulation when changing the interpretation of the law must be overcome by a reliable monitoring and forecas­ting system so that these changes contribute to the development of law and the effective achievement of the objectives of the criminal law.

Neuroelectrophysiology-compatible electrolytic lesioning.

Lesion studies have historically been instrumental for establishing causal connections between brain and behavior. They stand to provide additional insight if integrated with multielectrode techniques common in systems neuroscience. Here, we present and test a platform for creating electrolytic lesions through chronically implanted, intracortical multielectrode probes without compromising the ability to acquire neuroelectrophysiology. A custom-built current source provides stable current and allows for controlled, repeatable lesions in awake-behaving animals. Performance of this novel lesioning technique was validated using histology from ex vivo and in vivo testing, current and voltage traces from the device, and measurements of spiking activity before and after lesioning. This electrolytic lesioning method avoids disruptive procedures, provides millimeter precision over the extent and submillimeter precision over the location of the injury, and permits electrophysiological recording of single-unit activity from the remaining neuronal population after lesioning. This technique can be used in many areas of cortex, in several species, and theoretically with any multielectrode probe. The low-cost, external lesioning device can also easily be adopted into an existing electrophysiology recording setup. This technique is expected to enable future causal investigations of the recorded neuronal population's role in neuronal circuit function, while simultaneously providing new insight into local reorganization after neuron loss.

Ukrainian guidelines for the prevention and treatment of glucocorticoid-induced osteoporosis

Introduction. Glucocorticoid-induced osteoporosis (GIOP) is a bone metabolic disease that develops as a result of glucocorticoid (GC) use, is one of the most frequent causes of secondary osteoporosis, leads to an increase in the risk of low-energy fractures, disability and mortality of GC users. Despite the few stu­dies conducted in Ukraine on the epidemiology and treatment of GIOP, there have been no national recommendations for its ma­nagement until now, which has become the background for their creation. The purpose was to develop national guidelines for the diagnosis, prevention, and treatment of GIOP based on the analytical analysis of modern literary sources to improve the awareness of the medical community of Ukraine, improve management, and reduce the socio-economic burden of the disease. Materials and ­methods. A group of 18 experts, leading Ukrainian scientists in various fields, was created to develop the guideline. An analysis of current literary sources on epidemiology, risk factors, diagnosis, prevention and treatment of GIOP, and monitoring of the effectiveness and safety of its treatment was carried out. Evidence was synthesized ­using the GRADE system, and a critical assessment of the quality of the recommendations was carried out using the AGREE II tool. ­Results. The guideline consists of 12 provisions on screening, diagnosis, prevention, and treatment of GIOP. The authors emphasized the need to increase the awareness of the medical community of Ukraine regarding the problem, as well as patients regarding the possible side effects of GC. They presented the features of the clinical assessment of the osteoporotic fracture risk in GC users, as well as modern and available in Ukraine methods of diagnosis and treatment of GIOP. Conclusion. The first Ukrainian guideline for screening, diagnosis, prevention, and treatment of GIOP is an important national tool for its management, which is recommended by the Board of the Ukrainian Association of Osteoporosis for use in practical health care by doctors of various specialties.

Pollution Characteristics and Source Apportionment of Heavy Metals in Topsoil of Counties Along the Shandong Section of the Yellow River

The 25 counties along the Shandong section of the Yellow River are the core areas for promoting the ecological protection and high-quality development of the Yellow River in Shandong Province. Moreover, it is of great significance to study the current situation, sources, and potential risks of heavy metal pollution in the topsoil in this region. In this study, 103 soil samples were collected from the 25 counties along the Shandong section of the Yellow River, and the contents of eight heavy metals （As, Cu, Pb, Cr, Zn, Ni, Cd, and Hg） were determined. The pollution characteristics of heavy metals were analyzed and evaluated using the geological accumulation index and potential ecological risk index. Correlation analysis and the positive matrix factorization （PMF） model were used to analyze the sources of heavy metals. The results showed that the average contents of Cu and Cr were lower than that of the background values of soils, whereas the average contents of As, Pb, Zn, Ni, Cd, and Hg were 1.16, 1.42, 1.05, 1.14, 2.29, and 1.85 times higher than that of the background values, respectively, and the average contents of all eight elements were lower than the screening value of soil pollution risk in agricultural land. In terms of different heavy metal variations, the coefficient of variation （CV） of Cu and Cd was higher than 0.500, indicating high variations, whereas As, Pb, Cr, Zn, Ni, and Hg showed moderate variation. Cd and Hg were slightly polluted, whereas the other six elements were not polluted. Cd and Hg had a moderate potential ecological risk level, whereas the other six elements were at a low level. Correlation analysis and PMF model showed that the sources of heavy metals in the study area were influenced by four factors, i.e., agricultural activities, natural sources, industrial emissions, and atmospheric dust from coal combustion and vehicle exhaust emissions, and the relative contribution rates were 32.4%, 34.9%, 16.5%, and 16.2%, respectively.

Influence of Hippocrates on the development of modern medicine

Introduction: Hippocratic thought is not simply an echo of the past, but an eternal link that connects the historical roots of medicine with its contemporary evolution, being a fundamental guide for doctors in the search for technical excellence and ethical practice. Objective: Analyze the influence of Hippocrates on the development of modern medicine.Methods: A bibliographic review was carried out by consulting academic databases PubMed, Scopus and Google Scholar, and using specific keywords to identify and select relevant studies on the topic. High-quality and current sources were evaluated and synthesized, organizing the information into thematic categories for analysis.Results: The history of medicine is deeply intertwined with the scientific method, and in this context, Hippocrates stands out as a pioneer who paved the way towards evidence-based medicine. His scientific legacy, reflected in his teachings and practices, has endured through the centuries, shaping the way doctors approach the diagnosis and treatment of diseases.Conclusions: Although some of Hippocrates' theories have been surpassed, his contribution to establishing medicine as a respected and responsible profession remains essential in current medical care. His rational approach, medical ethics, preventive and comprehensive vision, and methods of diagnosis and treatment maintain the validity of his thinking.

POWER SUPPLY UNIT OF THE STAND AND LABORATORY INSTALLATION FOR TREATING OLIVES WITH ELECTROSTATIC FIELD

Most technological machines (TM) use hydraulic drives and internal combustion engines, such as lifting and transporting, loading and unloading, construction, road, track, and mining. Increasing the durability of the specified TM units is an urgent task. One of the possible solutions to this urgent problem is the electrostatic treatment of hydraulic oils and diesel fuels. Over the past three decades, researchers have conducted many studies focused on finding optimal means of using external force fields to improve the quality of lubricating materials and intensify their production. Types of influence of force fields, such as mechanical, mechanochemical, acoustic, electromagnetic, and electric, are increasingly used to regulate the behaviour of dispersed particles in nonpolar and slightly polar environments. The theory of regulated interphase transitions proves that the emergence, growth, and size change of supramolecular structures, surrounded by an adsorption-solvate layer and creating complex structural units in oil dispersion systems, contribute to the emergence of new properties of these systems. One of the main provisions of this theory is the need for extreme and antibating changes in the size of complex structural units with the help of external influences, which include force fields. Lubricating materials differ in their degrees of dispersity, composition, and properties, so the effect of force fields on them is diverse. The ability to regulate intermolecular interactions and the size of complex structural units are significant in the operation of lubricants. Electric fields make it possible to control phase interactions in these dispersed systems: they increase the constant dipole moments of particles and the electrosurface forces, which contribute to the deformation of the electric double layer. Under the action of strong electric fields, structural changes occur in hydrocarbon dispersion systems, which significantly change the physicochemical properties of lubricating materials. Thus, the dynamic viscosity of the lubricant and its resistance to deformation may change depending on the chemical nature of the system. Previously conducted experimental studies allow us to formulate the requirements for the stand in detail, which enables investigation of the properties of petroleum-based liquids. Thus, it is possible to achieve increased anti-wear properties of petroleum-based liquids when the liquid passes through the gap between the electrodes in an electrostatic field. The voltage between the electrodes should be U = 1000–1500 V, and the speed of the liquid movement in the space between the electrodes should be V = 4.5–6.5 m/s. The power supply unit of the stand for electroprocessing petroleum-based liquids, proposed in this paper, meets these requirements. The article proposes a fundamentally new scheme for the power supply unit of the laboratory stand for direct current electrotreatment of petroleum-based liquids. The power supply unit is a bipolar source of adjustable direct current. It provides smooth regulation of the voltage from 0 to 3000 V and step regulation of the output current. The block has double protection against short circuits at the output and input. Keywords: anti-wear property, oil, influence of an electrostatic field on the anti-wear properties of oil, device for electrostatic treatment of oil.

Improved Dipole Source Localization from Simultaneous MEG-EEG Data by Combining a Global Optimization Algorithm with a Local Parameter Search: A Brain Phantom Study.

Dipole localization, a fundamental challenge in electromagnetic source imaging, inherently constitutes an optimization problem aimed at solving the inverse problem of electric current source estimation within the human brain. The accuracy of dipole localization algorithms is contingent upon the complexity of the forward model, often referred to as the head model, and the signal-to-noise ratio (SNR) of measurements. In scenarios characterized by low SNR, often corresponding to deep-seated sources, existing optimization techniques struggle to converge to global minima, thereby leading to the localization of dipoles at erroneous positions, far from their true locations. This study presents a novel hybrid algorithm that combines simulated annealing with the traditional quasi-Newton optimization method, tailored to address the inherent limitations of dipole localization under low-SNR conditions. Using a realistic head model for both electroencephalography (EEG) and magnetoencephalography (MEG), it is demonstrated that this novel hybrid algorithm enables significant improvements of up to 45% in dipole localization accuracy compared to the often-used dipole scanning and gradient descent techniques. Localization improvements are not only found for single dipoles but also in two-dipole-source scenarios, where sources are proximal to each other. The novel methodology presented in this work could be useful in various applications of clinical neuroimaging, particularly in cases where recordings are noisy or sources are located deep within the brain.

Laminar organization of visual responses in core and parabelt auditory cortex

Abstract Audiovisual (AV) interaction has been shown in many studies of auditory cortex. However, the underlying processes and circuits are unclear because few studies have used methods that delineate the timing and laminar distribution of net excitatory and inhibitory processes within areas, much less across cortical levels. This study examined laminar profiles of neuronal activity in auditory core (AC) and parabelt (PB) cortices recorded from macaques during active discrimination of conspecific faces and vocalizations. We found modulation of multi-unit activity (MUA) in response to isolated visual stimulation, characterized by a brief deep MUA spike, putatively in white matter, followed by mid-layer MUA suppression in core auditory cortex; the later suppressive event had clear current source density concomitants, while the earlier MUA spike did not. We observed a similar facilitation-suppression sequence in the PB, with later onset latency. In combined AV stimulation, there was moderate reduction of responses to sound during the visual-evoked MUA suppression interval in both AC and PB. These data suggest a common sequence of afferent spikes, followed by synaptic inhibition; however, differences in timing and laminar location may reflect distinct visual projections to AC and PB.

Design and Performance Evaluation of an In Situ Online Soil Electrical Conductivity Sensor Prototype Based on the High-Performance Integrated Chip AD5941

Soil electrical conductivity has an important influence on the growth and development of plants. The existing real-time soil electrical conductivity detection device is affected by temperature, inconvenient to use, expensive, etc.; therefore, based on the classical four-terminal method of soil electrical conductivity detection principle, in this study, we aim to improve the limitations of the constant current source, selecting the high-performance integrated chip AD5941, optimizing the detection circuit and probe structure, improving the achievability of the detection circuit, and designing a type of in situ on-line real-time access to a soil electrical conductivity detection device, and improve the detection accuracy by temperature compensation. In this paper, dynamic performance, steady state performance, radial sensitivity range, and calibration test are carried out for the soil electrical conductivity detection prototype. The test results show that the dynamic response speed of the prototype is less than 50 ms, the steady state error is not more than ±2%, and the radial measurement sensitivity range is 8~10 cm. A comparison with the commercial sensor shows that the linear fit of the two measurements reaches 0.9995, and the absolute error ranges from −61.40 µS/cm to 23.90 µS/cm, with a relative error range of −1.94~1.86%. It shows that the performance of the two sensors is comparable, but the quality/price ratio of the prototype is much higher than that of the commercialized product. In this study, it is demonstrated that a high-precision, low-cost, and easy-to-use in situ online soil electrical conductivity detection device can be provided for agricultural and forestry production.

Low-current gliding DC discharge in high-speed flows

Abstract A low-current gliding discharge (current range 1–5 A) in high-speed air flows of 100–250 m s−1 was experimentally studied. A high-voltage direct current source with a maximum voltage of 4.5 kV was used to create the discharge. The average electron concentration n e ∼ 1014 cm−3 and the plasma ionization degree were determined by measuring the Stark broadening of the hydrogen H β line (λ Hβ = 486.1 nm). The estimates of the electric field (E ∼ 100 V cm −1 ÷ 600 V cm−1) in the discharge positive column were found using time-synchronized high-speed video recordings and oscillograms. The gas rotational temperature T g = 7000–9500 K and the vibrational temperature T v = 7000–11 000 K were estimated using optical emission spectroscopy. Time-resolved spectroscopy is used to investigate the effective plasma channel spatial regions from which the N, NH, N2 +, O and OH molecules radiate. The difference of the obtained radii indicates the presence of a radial temperature gradient and inhomogeneous plasma composition in the discharge cross section. The possibility of using of gliding discharge to ignite hydrocarbon-air mixtures in the ramjet engines combustors has been experimentally demonstrated.

Knowledge, attitude, and practice among kindergarten teachers regarding vision and eye screening of preschool children

Abstract: PURPOSE: To estimate the level and determinants of knowledge, attitude, and practices (KAPs) of kindergarten teachers regarding vision and eye screening of preschool children of Qassim region of Saudi Arabia. METHODS: As a part of a study to evaluate the KAP of stakeholders in the Qassim region, we surveyed kindergarten teachers from July to September 2023. The responses to ten knowledge-related and five attitudes and practices of teachers about eye and vision screening were collected using a graded Likert scale. The KAP score was associated with teacher-related variables. Teachers’ current and desired sources of knowledge were also reviewed. RESULTS: We surveyed 60 KG teachers. All were female. The good level of knowledge was in 85% of teachers. The positive attitude and good practices were in 90% of teachers. Teachers’ education levels were not associated with teachers’ knowledge (Kolmogorov–Smirnov [KS] P = 0.456), attitudes (KS P = 0.71), and practice (KS P = 0.06). Social media and computer-based sources provided knowledge on eye and vision screening of children in nearly half of the teachers. More interaction between ophthalmologists and optometrists was desired to learn about the topic. CONCLUSIONS: The high awareness, positive attitude, and practices noted among KG teachers in this study are promising and favor their involvement in universal vision and eye screening initiatives in the Qassim region of Saudi Arabia.

Generalized Modulation of Common Mode Voltage Reduction for Current Source Inverter in Balanced and Unbalanced Load Cases

Generalized Modulation of Common Mode Voltage Reduction for Current Source Inverter in Balanced and Unbalanced Load Cases

Research of electrode materials for the creation of multifunctional current sources with increased capacity as a components of the energy sector of an efficient urban environment

As part of creating a comfortable and safe environment, constructing energy-efficient residential and industrial buildings and structures that meet modern requirements and standards, the development of the production of environmentally friendly renewable and new individual energy sources is becoming especially relevant. In this regard, there is a need to increase the energy capacity of electrochemical cells. Research has been carried out on the metallized conductive materials creation based on rolled carbon non-woven material “Busofit” with the sequential application of metal coatings of titanium and silver using ion-plasma sputtering and electric pulse dispersion methods. It has been shown that surface layer metallization of the electrode material with titanium can improve the electrochemical cell characteristics. Additional silver film deposition leads to further cell performance improvement. It has been confirmed that the multilayer structure interfacial resistance between the carbon and the current collector has a significant effect on the conductivity of the electrochemical cell and the stability of its operation. The contact area increase of the electrode with the electrolyte leads to an increase in the rate processes occurring on the electrode surface and in the near-electrode space, which opens up prospects for increasing the energy intensity of the electrochemical system. A significant capacity increase of a water-based capacitor structure is achieved by the formation of a nanostructured dielectric layer of potassium titanate in the interelectrode space. It has been confirmed that the cell voltage cycling helps to stabilize the processes occurring in the surface layer of the electrode material at the interface and determining the range of mechanisms for transmitting electrical energy, which makes it possible to achieve higher energy intensity of the samples. Improvement of technological solutions in the field of ion-plasma technologies and the use of new perspective nanostructured materials creates the prerequisites for the creation of advanced automation and energy supply systems with a higher resource, which expands the possibilities of their use in various construction projects.

Identification Technique for Exponents and Current Source of Polynomial Flux Saturation Model for Synchronous Motors

Identification Technique for Exponents and Current Source of Polynomial Flux Saturation Model for Synchronous Motors

Current Source Gate Drivers: Topologies, Applications, and Future Research Needs

Current Source Gate Drivers: Topologies, Applications, and Future Research Needs

Novel Single-Stage Current Source Inverter: Extension to Low-Speed Region in Motor Drive Applications

Novel Single-Stage Current Source Inverter: Extension to Low-Speed Region in Motor Drive Applications

Performances of the e-Nauka Portal in the Republic of Serbia and Its Significance for Researchers

In recent years, digitalization has been recognized as a significant and necessary process that leads to better results, both in the education and in the scientific research. The legal and strategic framework in the Republic of Serbia follows the modern trends of the concept of open science, open knowledge, digital transformation and a unique digital format of scientific production. The Ministry of science, technological development and innovation, in cooperation with the Office for information technology and electronic administration, created the necessary conditions for dynamic the development of the scientific research and innovation system, especially in relation to the digitalization process and the establishment of an information platform, in the form of a unified national information system of scientific research activities: eNauka [eScience]. The concept of eNauka is an innovative tool that improves the efficiency and transparency of scientific processes in Serbia. The eNauka portal in the Republic of Serbia is dedicated to promoting scientific research, innovation and academic achievements within the scientific community of the Republic of Serbia. This portal provides access to scientific articles, research papers and academic publications authored by researchers from Serbia, which enables the spread of knowledge and the encouragement of scientific cooperation within the country. The eNauka portal was opened in full capacity for all active researchers in Serbia on July 3, 2023, and contains data on scientific research organizations in the Republic of Serbia, researchers and their scientific results. The goal of this paper was to bring closer to the academic community the capabilities and performance of the eNauka portal, its structure, the way and importance of data editing, with special reference to issues related to researchers’ profiles and their editing. The paper is methodologically based on a theoretical, preliminary desk analysis of relevant contemporary standpoints in domestic and foreign theory, a normative analysis of current legislative sources, an inductive and deductive approach in researching the operational performance and advantages of the eNauka portal, as well as the quantitative analysis of relevant statistical indicators of relevant parameters regarding the profile that each researcher has on the eNauka portal. The results include the analysis of data related to editing the researcher’s profile and the opportunities offered by the eNauka portal. The conclusion refers to the importance and advantages of the eNauke portal. Finally, it should be noted that one of the key functions of eNauka is the evaluation of scientific results. More precisely, the system provides the possibility of monitoring and evaluating research results, which is of great importance for the academic community.

Machine-learning aided calibration and analysis of porous media CFD models used for rotating packed beds

The proposed research is an attempt to advance the state-of-the-art of the numerical modelling of RPB by combining Computational Fluid Dynamics and Machine Learning approaches. The latter creates an accurate framework that should help quantify the potential of Rotating Packed Beds (RPB) technology to intensify conventional CO2 capture processes. To this end, a direct sensitivity analysis is detailed to supplement a machine-learning (ML) algorithm built for calibrating resistance coefficients needed for porous media modelling. The algorithm is used to improve CFD predictions of dry pressure drop in rotating packed beds (RPBs) for a wide range of operating conditions. The sensitivity derivatives with respect to the packing resistance coefficients are demonstrated for the first time in RPBs, which is not available in the current CFD open source and commercial codes. In this regard, sensitivity differential equations are derived from three-dimensional Navier-Stokes equations for porous media in a rotating reference frame. These sensitivity equations are discretized using a finite volume scheme and solved to obtain the sensitivity pressure drop differences at the packing edges. The results are validated against the predictions of the analytical sensitivity analysis and the finite difference approximation. After, the Newton – Gauss method that employs the sensitivity pressure drop derivatives, is used to minimize the error (cost function) between the pressure drop obtained from CFD simulations and the available experimental data. This is achieved by tuning the packing resistance coefficients to the RBPs' operating conditions (gas flowrate and rotating speed) and correlate them using an artificial neural network (ANN). The results of the proposed approach show a significant improvement in porous media-based CFD predictions of RPBs' pressure drop across a wide range of operating conditions and this over conventional porous media-based CFD models. This is necessary for CFD models to be reliably used as a tool that can efficiently improve existing RPBs' designs and/or participate in RPBs' design innovation.

Consideration of DC/DC converter for photovoltaics with soft switching with modified push-pull current source inverter circuit

Consideration of DC/DC converter for photovoltaics with soft switching with modified push-pull current source inverter circuit