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The evaluation of land suitability for agricultural production is a complex process that requires specialized information and expert analysis. This paper introduces the Soil Suitability Evaluation (SSE) model, a computer program designed to assess land suitability for agriculture. The model considers soil surface conditions (erosion, micro-relief, and slope), physical characteristics (texture and depth), and chemical properties (salinity, sodicity, fertility, and calcium carbonate). It involves calculating these soil characteristics along with their respective weights. Compared to other land suitability evaluation methods, the SSE model provides realistic and practical results including assessments of soil and crop suitability. It serves as a simple and useful tool for decision-makers to determine land quality for agricultural use and proposed some recommendations for land reclamation. [ABSTRACT FROM AUTHOR]

Gaussian process regression models are used as statistical representations of computational models, due to their flexibility in capturing the shape of smooth functions. The Gaussian process regression model has a number of parameters, the estimation of which is an essential step towards building the model. The parameters considered are the regression coefficients , the scaling parameter and the correlation lengths . Estimating these parameters is the problem we address in this paper. The main contribution of this work is a comparison between estimating the parameters of the Gauss process regression model using the maximum likelihood method and the restricted maximum likelihood method. This comparison was made based on some validation measures. The Gauss process regression model, whose parameters were estimated using the two methods above, was applied to a real eight-dimensional example represented by the borehole function model, and all mathematical and graphical operations were carried out using the R program.

The function of the smooth muscle cells lining the walls of mammalian systemic arteries and arterioles is to regulate the diameter of the vessels to control blood flow and blood pressure. Here, we describe an in silico model, which we call the 'Hernandez-Hernandez model', of electrical and Ca2+ signaling in arterial myocytes based on new experimental data indicating sex-specific differences in male and female arterial myocytes from murine resistance arteries. The model suggests the fundamental ionic mechanisms underlying membrane potential and intracellular Ca2+ signaling during the development of myogenic tone in arterial blood vessels. Although experimental data suggest that KV1.5 channel currents have similar amplitudes, kinetics, and voltage dependencies in male and female myocytes, simulations suggest that the KV1.5 current is the dominant current regulating membrane potential in male myocytes. In female cells, which have larger KV2.1 channel expression and longer time constants for activation than male myocytes, predictions from simulated female myocytes suggest that KV2.1 plays a primary role in the control of membrane potential. Over the physiological range of membrane potentials, the gating of a small number of voltage-gated K+ channels and L-type Ca2+ channels are predicted to drive sex-specific differences in intracellular Ca2+ and excitability. We also show that in an idealized computational model of a vessel, female arterial smooth muscle exhibits heightened sensitivity to commonly used Ca2+ channel blockers compared to male. In summary, we present a new model framework to investigate the potential sex-specific impact of antihypertensive drugs.

Introduction. Today, there is an increasing reliance on computer computational models to assess the load-bearing capacity of building structures. However, a very small number of studies address issues of ensuring the reliability of the obtained results. In the current design practice, the design reliability of structures is provided by a system of partial reliability factors that take into account the uncertainty of random variable and the accuracy of the model. Therefore, fixing the values of reliability factors or the methodology for determining them in the design standards is especially important.Materials and methods. The proposed method for determining reliability factors and their values are based on the methods of reliability theory and probability theory. Statistical characteristics of random variables and accuracy of the computer model are based on the systematization, analysis and generalization of existing studies.Results. The paper presents a system of reliability factors and a method for determining them for the studied construction solutions and standardized parameters of computer models. The results of studies of statistical characteristics of the measure of accuracy of computer models are presented. The values of conversion coefficients are proposed, which allow taking into account different models of the material, the degree of discretization and the values of imperfections.Conclusions. In the field of design of building structures, two extreme cases of using computer numerical models from the position of knowledge of the studied object (for new structural solutions and for studied solutions) and two extreme cases from the position of knowledge of model parameters (validated (standardized) or non-validated (non-standardized) computer model parameters are used). Depending on the case under consideration, model verification procedures should be specified and ways to ensure design reliability should be assigned.

The relevance of the study lies in the consideration and correction of the results of calculations of the single-phase short circuit current in a rural 0.4 kV electric network obtained using existing physical, computer and mathematical methods that give different results. Purpose. Development of correction coefficients for different methods of calculating the single-phase short circuit current in a rural 0.4 kV electrical network. Materials and research methods. During the calculations of the single-phase short circuit current in the 0.4 kV rural electric grid, using different methods, general initial conditions were set: power was supplied from a TM-250 transformer and using A-35 wire. Results. It was revealed that the error between the results obtained using different methods reaches 35.9%. In the work, correction coefficients with values from 0.93 to 1.47 relative units were proposed in order to increase the reliability of calculations. These coefficients made it possible to increase the reliability of the considered methods for determining the current of a single-phase short circuit in a rural 0.4 kV electrical network by 2.9-6.1 times compared with the initial values.

A study of the boundaries of the working space of a three-link planar manipulator, specified by analytical equations, is carried out. A new geometric interpretation of these samples is proposed. On its basis, it is established that outer space consists of two-parameter volumes of eccentric and concentric circles. When transforming such environments into four-dimensional space, two types of hypersurfaces are obtained, which represent a geometric model of the manipulator's workspace. The discriminants of these hypersurfaces on the hyperplane are two two-dimensional surfaces. Both an analytical description of these surfaces and their computer models are obtained. As a result, it is established that the boundaries of the working space on the plane of the mechanism are the discriminants of such surfaces. To confirm the reliability of the results obtained, as an example, an inverse kinematics problem is solved on discriminant surfaces — the values of generalized coordinates at the boundary points of the manipulator’s workspace are determined for their given Cartesian coordinates.

Aims The effective refractory period (ERP) is one of the main electrophysiological properties governing arrhythmia, yet ERP personalization is rarely performed when creating patient-specific computer models of the atria to inform clinical decision-making. This study evaluates the impact of integrating clinical ERP measurements into personalized in silico models on arrhythmia vulnerability. Methods and results Clinical ERP measurements were obtained in seven patients from multiple locations in the atria. Atrial geometries from the electroanatomical mapping system were used to generate personalized anatomical atrial models. The Courtemanche M. et al. cellular model was adjusted to reproduce patient-specific ERP. Four modeling approaches were compared: homogeneous (A), heterogeneous (B), regional (C), and continuous (D) ERP distributions. Non-personalized approaches (A and B) were based on literature data, while personalized approaches (C and D) were based on patient measurements. Modeling effects were assessed on arrhythmia vulnerability and tachycardia cycle length, with sensitivity analysis on ERP measurement uncertainty. Mean vulnerability was 3.4 ± 4.0%, 7.7 ± 3.4%, 9.0 ± 5.1%, and 7.0 ± 3.6% for scenarios A–D, respectively. Mean tachycardia cycle length was 167.1 ± 12.6 ms, 158.4 ± 27.5 ms, 265.2 ± 39.9 ms, and 285.9 ± 77.3 ms for scenarios A–D, respectively. Incorporating perturbations to the measured ERP in the range of 2, 5, 10, 20, and 50 ms changed the vulnerability of the model to 5.8 ± 2.7%, 6.1 ± 3.5%, 6.9 ± 3.7%, 5.2 ± 3.5%, and 9.7 ± 10.0%, respectively. Conclusion Increased ERP dispersion had a greater effect on re-entry dynamics than on vulnerability. Inducibility was higher in personalized scenarios compared with scenarios with uniformly reduced ERP; however, this effect was reversed when incorporating fibrosis informed by low-voltage areas. Effective refractory period measurement uncertainty up to 20 ms slightly influenced vulnerability. Electrophysiological personalization of atrial in silico models appears essential and requires confirmation in larger cohorts. [ABSTRACT FROM AUTHOR]

The Myelodysplastic syndromes (MDS) are a heterogenous group of clonal bone marrow (BM) stem cell myeloid neoplasms, characterized by ineffective hematopoiesis that results in dysplasia in hematopoietic cells and peripheral cytopenias, especially anemia, and a propensity to leukemic transformation. The suspicion of MDS is raised by a typical but not specific clinical picture and routine laboratory findings, but the gold standard for MDS diagnosis is still BM examination with the presence of uni-or multi-lineage dysplasia and increased blast percentage, together with exclusion of other reasons. Cytogenetics is also an essential part of the diagnostic and prognostic processes. Flow cytometry and full genetic characterization are helpful but not mandatory for MDS diagnosis. This review summarizes the current steps of diagnostic approach for a patient suspected of having MDS. We also express our hopes that within the near future, non-invasive technologies, especially digital and peripheral blood genetics, will mature and be introduced into practice. [ABSTRACT FROM AUTHOR]

RELEVANCE. The challenges of creating modern permanent magnet synchronous motors require solving technical problems in conjunction with economic realities. Due to the use of permanent magnets in the construction of synchronous motors, their cost limits their industrial application. Therefore, there is an urgent issue of optimizing the design of synchronous motors, which can be solved by changing the topology.TARGET. The goal is to create more economical permanent magnet synchronous motors (PMSMs) in low-power electric vehicles. It is planned to implement a new method for constructing PMSM. This solution will reduce weight and size parameters and increase specific power, which are important indicators for electric transport.METHODS. To modernize modern synchronous motors, a complex topological optimization method based on a genetic algorithm is proposed.RESULTS. A computer model was obtained in the form of calculation of electromagnetic fields in the stator and rotor of a synchronous motor with permanent magnets.CONCLUSION. Modeling the parameters of synchronous motors with permanent magnets has a low degree of development in the domestic mechanical engineering due to the lack of developed infrastructure in the field of low-power electric transport; the creation of domestic developments in this area is of a strategic nature.

Introduction. In the poultry industry, the use of local LED lighting systems with changeable light and correlated color temperature of the luminaire optical radiation during the photoperiod is promising. To maintain light intensity accurately at a specified level, the use of an automatic control system (ACS) of lighting is required. Aim of the Study. The study at aimed at determining the parameters for the PI controller of the digital ACS of lighting in all-age cages, providing the required quality indicators of the regulatory process. Materials and Methods. For the study there were used the elements of mathematical statistics, experimental research design theory, correlation and regression analysis, automatic control theory and computer simulation. Real experiments were carried out on a laboratory sample of a digital dynamic local lighting system. Computer simulation was performed in the SimInTech program. Results. A computer model for a digital ACS of lighting has been developed. The tunings of the PI controller were calculated using the CHR, VTI, and Kopelovich methods. A comparative estimation of the control process quality was carried out using graphs of transient processes obtained by computer simulation. The reliability of the results of computer simulation of ACS lighting has been confirmed experimentally. Discussion and Conclusion. High regulator performance indicators for the digital ACS of lighting were ensured by a PI controller with kP = 14.027∙10−3 and TI = 145.72 ms calculated using the Kopelovitch method. A comparative assessment of transient processes in a real ACS and in a computer model of this system allows concluding that the developed model is highly accurate and the choice of simulation parameters in the SimInTech program is correct. It has been experimentally established that the required quality of the control process of ACS is ensured for a wide range of specified lighting: from 1 to 25 lux.

Annually, over 300 million surgeries occur globally, requiring numerous surgical instruments. However, many instruments on the tray are returned to the central sterile supply department (CSSD) unused, creating an unsustainable pattern of unnecessary consumption. To address this, we developed a method for optimising surgical instrument trays (SITs) that is straightforward to implement in other hospitals. This optimisation aims to enhance patient safety and sustainability and to improve working conditions and reduce costs. We identified actual instrument usage (IU) in the operating room (OR) and obtained expert recommendations (ERs). Data from both methods were combined in a computer model (CM) to adjust the SITs. The performance of the adjusted SITs was assessed over a year. IU of three different SITs was collected during 16 procedures (mean = 28.4%, SD = 6.4%). Combining IU and ERs resulted in a 36.7% reduction in instruments and a 31.3% weight reduction. These measures contribute to reducing the carbon footprint and enhancing sustainability. During the evaluation of the new SIT contents (n = 7 procedures), mean IU increased from 28.4% (SD = 6.4%) to 46.5% (SD = 11.0%), with no missing instruments during surgery. A one-year follow-up showed no need for further alterations. Combining both methods yields better results than using them individually, efficiently reducing unnecessary items in SITs without compromising patient safety. [ABSTRACT FROM AUTHOR]

A computer model predicting thresholds for laser induced corneal injury was used to systematically analyze wavelength, pulse duration, and beam diameter dependencies for wavelengths between 1200 and 1500 nm, for the exposure duration regime of 10 μs to 100 s. The thresholds were compared with the maximum permissible exposure (MPE) values to protect the cornea as specified in ANSI Z136.1-2022, ICNIRP 2013, and IEC 60825-1:2014. In the wavelength range between 1200 and 1400 nm, the dominant hazard transitions from the retina to the cornea. Consequently, limits are needed to protect both the cornea and the retina. In the lower wavelength range, the retinal limits are more conservative, while in the higher wavelength range, the corneal limits are lower. Comparison with injury thresholds shows that ANSI MPEs include a large safety margin for all wavelengths. Due to the 7 mm aperture stop defined in IEC 60825-1, levels permitted by the Class 3B limit exceed the predicted injury thresholds for small beam diameters and wavelengths between approximately 1350 and 1400 nm. The Class 3B limit does not appear to be sufficiently protective for these conditions. For skin MPEs, the margin between corneal injury thresholds and MPEs decreases steadily for wavelengths approaching 1400 nm. However, normal eye movements can be expected to reduce the effective exposure so that skin MPEs may serve as adequate limits to protect the cornea for wavelengths less than 1400 nm until a specific limit to protect the cornea is promulgated by ICNIRP. [ABSTRACT FROM AUTHOR]

Introduction: Fibrotic scar in the heart is known to act as a substrate for arrhythmias. Regions of fibrotic scar are associated with slowed or blocked conduction of the action potential, but the detailed mechanisms of arrhythmia formation are not well characterised and this can limit the effective diagnosis and treatment of scar in patients. The aim of this computational study was to evaluate different representations of fibrotic scar in models of 2D 10 x 10 cm ventricular tissue, where the region of scar was defined by sampling a Gaussian random field with an adjustable length scale of between 1.25 and 10.0 mm. Methods: Cellular electrophysiology was represented by the Ten Tusscher 2006 model for human ventricular cells. Fibrotic scar was represented as a spatially varying diffusion, with different models of the boundary between normal and fibrotic tissue. Dispersion of activation time and action potential duration (APD) dispersion was assessed in each sample by pacing at an S1 cycle length of 400 ms followed by a premature S2 beat with a coupling interval of 323 ms. Vulnerability to reentry was assessed with an aggressive pacing protocol. In all models, simulated fibrosis acted to delay activation, to increase the dispersion of APD, and to generate re-entry. Results: A higher incidence of re-entry was observed in models with simulated fibrotic scar at shorter length scale, but the type of model used to represent fibrotic scar had a much bigger influence on the incidence of reentry. Discussion: This study shows that in computational models of fibrotic scar the effects that lead to either block or propagation of the action potential are strongly influenced by the way that fibrotic scar is represented in the model, and so the results of computational studies involving fibrotic scar should be interpreted carefully. [ABSTRACT FROM AUTHOR]

The light-induced transthylakoid membrane potential (ΔΨ m) can function as a driving force to help catalyzing the formation of ATP molecules, proving a tight connection between ΔΨ m and the ATP synthase. Naturally, a question can be raised on the effects of altered functioning of ATP synthases on regulating ΔΨ m , which is attractive in the area of photosynthetic research. Lots of findings, when making efforts of solving this difficulty, can offer an in-depth understanding into the mechanism behind. However, the functional network on modulating ΔΨ m is highly interdependent. It is difficult to comprehend the consequences of altered activity of ATP synthases on adjusting ΔΨ m because parameters that have influences on ΔΨ m would themselves be affected by ΔΨ m. In this work, a computer model was applied to check the kinetic changes in polarization/depolarization across the thylakoid membrane (TM) regulated by the modified action of ATP synthases. The computing data revealed that under the extreme condition by numerically "switching off" the action of the ATP synthase, the complete inactivation of ATP synthase would markedly impede proton translocation at the cytb 6 f complex. Concurrently, the KEA3 (CLCe) porter, actively pumping protons into the stroma, further contributes to achieving a sustained low level of ΔΨ m. Besides, the quantitative consequences on every particular component of ΔΨ m adjusted by the modified functioning of ATP synthases were also explored. By employing the model, we bring evidence from the theoretical perspective that the ATP synthase is a key factor in forming a transmembrane proton loop thereby maintaining a propriate steady-state ΔΨ m to meet variable environmental conditions. • Quantitatively assessing the dynamics in ΔΨ m and its components during repetitive light-dark transitions. • Quantitatively assessing the impact of modified ATP synthase functionality on ΔΨ m and its components. • Chloroplast ATP synthase plays a crucial role in the formation of a transthylakoid proton loop to maintain an efficient photosynthesis rate. [ABSTRACT FROM AUTHOR]

Copyright of Herzschrittmachertherapie und Elektrophysiologie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aims Human induced pluripotent stem cell–derived atrial cardiomyocytes (hiPSC-aCM) could be a helpful tool to study the physiology and diseases of the human atrium. To fulfil this expectation, the electrophysiology of hiPSC-aCM should closely resemble the situation in the human atrium. Data on the contribution of the slowly activating delayed rectifier currents (I Ks) to repolarization are lacking for both human atrium and hiPSC-aCM. Methods and results Human atrial tissues were obtained from patients with sinus rhythm (SR) or atrial fibrillation (AF). Currents were measured in human atrial cardiomyocytes (aCM) and compared with hiPSC-aCM and used to model I Ks contribution to action potential (AP) shape. Action potential was recorded by sharp microelectrodes. HMR-1556 (1 µM) was used to identify I Ks and to estimate I Ks contribution to repolarization. Less than 50% of hiPSC-aCM and aCM possessed I Ks. Frequency of occurrence, current densities, activation/deactivation kinetics, and voltage dependency of I Ks did not differ significantly between hiPSC-aCM and aCM, neither in SR nor AF. β-Adrenoceptor stimulation with isoprenaline did not increase I Ks neither in aCM nor in hiPSC-aCM. In tissue from SR, block of I Ks with HMR-1556 did not lengthen the action potential duration, even when repolarization reserve was reduced by block of the ultra-rapid repolarizing current with 4-aminopyridine or the rapidly activating delayed rectifier potassium outward current with E-4031. Conclusion I Ks exists in hiPSC-aCM with biophysics not different from aCM. As in adult human atrium (SR and AF), I Ks does not appear to relevantly contribute to repolarization in hiPSC-aCM. [ABSTRACT FROM AUTHOR]

A Mullins simulation was conducted to analyze the effects of loading and unloading of a flexible-type SEGE coupling with a nominal torque of T n o m = 80   N m and maximum torque of T m a x = 120   N m . The coupling's properties were determined by examining its moment characteristics at T = 120 ,   100 ,   80 ,   60 ,   40 ,   a n d   20   N m . The correlation between the Mullins effect results obtained from the SEGE coupling load simulation via SolidWorks 2022 software and the actual experimental data was examined. [ABSTRACT FROM AUTHOR]

The Myelodysplastic syndromes (MDS) are a heterogenous group of clonal bone marrow (BM) stem cell myeloid neoplasms, characterized by ineffective hematopoiesis that results in dysplasia in hematopoietic cells and peripheral cytopenias, especially anemia, and a propensity to leukemic transformation. The suspicion of MDS is raised by a typical but not specific clinical picture and routine laboratory findings, but the gold standard for MDS diagnosis is still BM examination with the presence of uni-or multi-lineage dysplasia and increased blast percentage, together with exclusion of other reasons. Cytogenetics is also an essential part of the diagnostic and prognostic processes. Flow cytometry and full genetic characterization are helpful but not mandatory for MDS diagnosis. This review summarizes the current steps of diagnostic approach for a patient suspected of having MDS. We also express our hopes that within the near future, non-invasive technologies, especially digital and peripheral blood genetics, will mature and be introduced into practice.

Investigation of the stress state of the metal frame of a ribbed-ring dome, when the number of supporting columns under it is gradually reduced. With that, the same distances or steps between the columns are maintained along the entire contour of the support ring. The main elements of the dome frame and columns are made of steel I-beams. Frames, the domes of which are supported by a different number of cyclically symmetrical columns, were considered as subjects of research. All the domes are characterized by the same geometric structure and size, the same cross sections of the same type of frame elements and are exposed to the same loads. The research was carried out on computer models by calculating the combined effect of the load from the weight of load-bearing and enclosing structures and an asymmetric snow load. The models with a reduced number of columns are obtained by regularly removing them from the original computer model. During the analysis, the stresses in the elements of the frames of all models were determined, which were compared with each other. Deformation graphs and comparative diagrams of the stress state relationships of the frame elements of the original and transformed models are obtained. An assessment of the change in the stress state of the ribbed-ring dome frame with a decrease in the number of columns is given. Significant changes in the stress state of the support ring were noted.

This study aims to build a computer model to detect built-up land in the identified tsunami hazard zone based on Sentinel 2A imagery using the normalized built up area index (NBI), urban index (UI), normalize difference build-up index (NDBI), a modified built-up index (MBI), index-based builtup index (IBI) algorithms, optimized with machine learning Random Forest (RF) and extreme gradient boosting (XGboost) algorithms and the spatial patterns are predicted using the ordinary kriging (OK) method. Testing of the accuracy of the classification and optimization results was performed using the Kohen Kappa and overall accuracy functions. The results of the study show that a built-up land consisting of open land and water, settlements, industry areas, and agriculture and tourism areas can be identified using the parameters of built-up indices. The accuracy testings that were performed using overall accuracy and Kohen Kappa methods show that classification and prediction are highly accurate using XGboost machine learning, namely >91%. This study produces a novelty of finding, namely a computer model to detect and predict the spatial distribution of built-up land in 4 scales, i.e., very low, low, high, and very high based on NBI, UI, NDBI, MBI, IBI data extracted from Sentinel 2A imagery. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduction: Fibrotic scar in the heart is known to act as a substrate for arrhythmias. Regions of fibrotic scar are associated with slowed or blocked conduction of the action potential, but the detailed mechanisms of arrhythmia formation are not well characterised and this can limit the effective diagnosis and treatment of scar in patients. The aim of this computational study was to evaluate different representations of fibrotic scar in models of 2D 10 × 10 cm ventricular tissue, where the region of scar was defined by sampling a Gaussian random field with an adjustable length scale of between 1.25 and 10.0 mm.Methods: Cellular electrophysiology was represented by the Ten Tusscher 2006 model for human ventricular cells. Fibrotic scar was represented as a spatially varying diffusion, with different models of the boundary between normal and fibrotic tissue. Dispersion of activation time and action potential duration (APD) dispersion was assessed in each sample by pacing at an S1 cycle length of 400 ms followed by a premature S2 beat with a coupling interval of 323 ms. Vulnerability to reentry was assessed with an aggressive pacing protocol. In all models, simulated fibrosis acted to delay activation, to increase the dispersion of APD, and to generate re-entry.Results: A higher incidence of re-entry was observed in models with simulated fibrotic scar at shorter length scale, but the type of model used to represent fibrotic scar had a much bigger influence on the incidence of reentry.Discussion: This study shows that in computational models of fibrotic scar the effects that lead to either block or propagation of the action potential are strongly influenced by the way that fibrotic scar is represented in the model, and so the results of computational studies involving fibrotic scar should be interpreted carefully.

The main method for estimating the level of arterial blood oxygenation is pulse oximetry, which has the advantages of being fast, simple, reliable, and non-invasive. However, in well-known pulse oximeters, oxygen saturation is determined only by hemoglobin functional fractions, which reduces the device accuracy and is unacceptable in certain clinical cases. The known pulse oximeter improvement that considers the dysfunctional fraction concentration, especially carboxyhemoglobin, when measuring the level of blood oxygenation is an actual scientific and technical task. The research subjects. Mathematical, algorithmic, and technical support of a pulse oximeter that measures blood oxygenation levels considering the carboxyhemoglobin concentration. Objective. To expand the pulse oximeter functionality to consider the concentration of carboxyhemoglobin in arterial blood. Methods. Methods of computer simulation for developing a model and estimating the pulse oximeter accuracy that measures the blood oxygenation level considering the carboxyhemoglobin concentration. Results. The theoretical statements of measuring the level of blood oxygenation considering the carboxyhemoglobin concentration and the simplest pulse oximeter structural diagram for measuring are developed. An additional LED used in the pulse oximeter is proposed, and the wavelength choice is justified on the condition of maximizing the carboxyhemoglobin contribution to the optical density of the biological object. Computer models of a traditional pulse oximeter and a pulse oximeter with an additional LED were developed, simulation research was conducted using the developed models, and the device accuracy for measuring the level of blood oxygenation was estimated considering the carboxyhemoglobin concentration. Conclusions. Simulation studies based on the developed models show that the proposed pulse oximeter, compared with the known one, allows determining and estimating a decrease in blood oxygenation caused by the carboxyhemoglobin concentration increasing in the patient’s blood. Considering that light is also absorbed by the third derivative of hemoglobin, carboxyhemoglobin, increases the accuracy of the proposed pulse oximeter in measuring functional saturation.

Studies of several metal ribbed-ring large-span domes on computer models have been carried out. All elements of the dome frames are made of steel I-beams. The dome frames have the same number of ribs and rings, but they have different size of the upper ring. The frame elements cross-sections are oriented normally to the dome surfaces, with the exception of the upper ring. The joints of the frame elements with each other are assumed to be rigid in the normal direction and hinged in the tangential direction. The frames are mounted on support nodes at the level of the lower ring pivotally. All the domes are subjected to the same nodal loads from the weight of the enclosing structures and the weight of snow. The snow load is assumed to be asymmetrical, located only on one side of the dome. Under the combined action of these loads, the dimensions of the upper ring of the domes influence the stress-strain state of their frames. As a result of the research, graphs have been generated representing the stress level in the meridional ribs and in the upper rings of the domes. The conclusion has been made that the stress state of metal dome frames depends on the size of the upper ring. The necessity of increasing the cross-section of the upper ring with an increase in its size has been noted.

A computer model of the system for generating neutron fluxes at the output of a linear electron accelerator has been developed in the Geant4 and PhysList QGSP BIC HP programming environment. With the help of the model, a number of virtual experiments on 107 primary neutrons were carried out. The dependence of the ratio of the number of neutrons, incident on the detector with a reflector to the number of neutrons without a reflector on the radius of curvature of the hemispherical dome of the reflector is determined, which makes it possible to establish the optimal dimensions of the working area. The energy spectra of neutrons incident on the detector are determined. It has been established that when using a graphite reflector 30 × 30 × 30 cm in size with a radius of curvature of the hemispherical dome of 5 cm, the number of neutrons at the location of the detector increases by 16.9 %, and the neutron background in the accelerator bunker decreases by 2.5 times, which is in good agreement with the real experiment made. Such a decrease in the radiation background, according to sanitary standards, will make it possible to increase the accelerator current by 2.5 times and increase the neutron flux.

One of measures to reduce the flood impact in Indonesia has been done by flood emergency response action plan. The action plan is generated from decision making process assisted by instrument such computer models which have capability in producing scenarios and decision to be taken. This research is conducted to identify how the written procedures (delivered by international and national agencies) related to flood emergency response, being accommodated by those (computer) models. By using qualitative analysis, the element procedures of an effective flood emergency response model have been reviewed. The result shows that the detailed information such human and material resources, facilities information, and warning time-lag, have not been properly and entirely accommodated by the (computer) model. Highlights are also given to propose more effective instrument to improve the management of flood crisis. [ABSTRACT FROM AUTHOR]

The main method for estimating the level of arterial blood oxygenation is pulse oximetry, which has the advantages of being fast, simple, reliable, and non-invasive. However, in well-known pulse oximeters, oxygen saturation is determined only by hemoglobin functional fractions, which reduces the device accuracy and is unacceptable in certain clinical cases. The known pulse oximeter improvement that considers the dysfunctional fraction concentration, especially carboxyhemoglobin, when measuring the level of blood oxygenation is an actual scientific and technical task. The research subjects. Mathematical, algorithmic, and technical support of a pulse oximeter that measures blood oxygenation levels considering the carboxyhemoglobin concentration. Objective. To expand the pulse oximeter functionality to consider the concentration of carboxyhemoglobin in arterial blood. Methods. Methods of computer simulation for developing a model and estimating the pulse oximeter accuracy that measures the blood oxygenation level considering the carboxyhemoglobin concentration. Results. The theoretical statements of measuring the level of blood oxygenation considering the carboxyhemoglobin concentration and the simplest pulse oximeter structural diagram for measuring are developed. An additional LED used in the pulse oximeter is proposed, and the wavelength choice is justified on the condition of maximizing the carboxyhemoglobin contribution to the optical density of the biological object. Computer models of a traditional pulse oximeter and a pulse oximeter with an additional LED were developed, simulation research was conducted using the developed models, and the device accuracy for measuring the level of blood oxygenation was estimated considering the carboxyhemoglobin concentration. Conclusions. Simulation studies based on the developed models show that the proposed pulse oximeter, compared with the known one, allows determining and estimating a decrease in blood oxygenation caused by the carboxyhemoglobin concentration increasing in the patient's blood. Considering that light is also absorbed by the third derivative of hemoglobin, carboxyhemoglobin, increases the accuracy of the proposed pulse oximeter in measuring functional saturation. [ABSTRACT FROM AUTHOR]

A Mullins simulation was conducted to analyze the effects of loading and unloading of a flexible-type SEGE coupling with a nominal torque of Tnom=80 Nm and maximum torque of Tmax=120 Nm. The coupling’s properties were determined by examining its moment characteristics at T=120, 100, 80, 60, 40, and 20 Nm. The correlation between the Mullins effect results obtained from the SEGE coupling load simulation via SolidWorks 2022 software and the actual experimental data was examined.

The function of the smooth muscle cells lining the walls of mammalian systemic arteries and arterioles is to regulate the diameter of the vessels to control blood flow and blood pressure. Here, we describe an in silico model, which we call the ‘Hernandez–Hernandez model’, of electrical and Ca2+ signaling in arterial myocytes based on new experimental data indicating sex-specific differences in male and female arterial myocytes from murine resistance arteries. The model suggests the fundamental ionic mechanisms underlying membrane potential and intracellular Ca2+ signaling during the development of myogenic tone in arterial blood vessels. Although experimental data suggest that KV1.5 channel currents have similar amplitudes, kinetics, and voltage dependencies in male and female myocytes, simulations suggest that the KV1.5 current is the dominant current regulating membrane potential in male myocytes. In female cells, which have larger KV2.1 channel expression and longer time constants for activation than male myocytes, predictions from simulated female myocytes suggest that KV2.1 plays a primary role in the control of membrane potential. Over the physiological range of membrane potentials, the gating of a small number of voltage-gated K+ channels and L-type Ca2+ channels are predicted to drive sex-specific differences in intracellular Ca2+ and excitability. We also show that in an idealized computational model of a vessel, female arterial smooth muscle exhibits heightened sensitivity to commonly used Ca2+ channel blockers compared to male. In summary, we present a new model framework to investigate the potential sex-specific impact of antihypertensive drugs.

In the work the computer model of a cell of a system for generating fluxes of therapeutic beams of delayed neutrons, based on the use of delayed fission neutrons, was developed in the Geant 4 environment. The principle of such a neutron source is that when a powerful electron beam interacts with a combined tungsten target and a target containing fissile material, a fission reaction occurs; as a result of which neutrons are emitted. If we move a target activated in this way several tens of meters into a neutron flux generation system consisting of a heater, protection, collimator and reflector, we will obtain a compact neutron source for nuclear medicine. A significant advantage of such a neutron source is the absence of gamma background from the electron accelerator and the combined target, and a bulky protection system is not required. In the Geant 4 environment, the geometry of this cell was developed and a series of experiments were carried out with 107 neutrons. The QGSP BIC HP physical sheet was used. A study of neutron energy spectra showed that more than half of the neutrons whose fluxes are formed using such a cell of the formation system have an energy

The article presents a comparative analysis of the methods for manufacturing polypropylene Raschig rings (taking account of consumption coefficients in manufacture of thermoplastic products) on the example of mass-exchange packings for the drying tower of a sulfuric acid plant. Graphical relationships and regression equations for Raschig ring (diameter 75 mm) mass-exchange packings made of polypropylene (taking account of the manufacturing method) are presented. [ABSTRACT FROM AUTHOR]

The single-celled baker's yeast, Saccharomyces cerevisiae, can sustain a number of amyloid-based prions, the three most prominent examples being [URE3], [PSI+], and [PIN+]. In the laboratory, haploid S. cerevisiae cells of a single mating type can acquire an amyloid prion in one of two ways (i) spontaneous nucleation of the prion within the yeast cell, and (ii) receipt via mother-to-daughter transmission during the cell division cycle. Similarly, prions can be lost due to (i) dissolution of the prion amyloid by its breakage into non-amyloid monomeric units, or (ii) preferential donation/retention of prions between the mother and daughter during cell division. Here we present a computational tool (Monitoring Induction and Loss of prions in Cells; MIL-CELL) for modelling these four general processes using a multiscale approach describing both spatial and kinetic aspects of the yeast life cycle and the amyloid-prion behavior. We describe the workings of the model, assumptions upon which it is based and some interesting simulation results pertaining to the wave-like spread of the epigenetic prion elements through the yeast population. MIL-CELL is provided as a stand-alone GUI executable program for free download with the paper. MIL-CELL is equipped with a relational database allowing all simulated properties to be searched, collated and graphed. Its ability to incorporate variation in heritable properties means MIL-CELL is also capable of simulating loss of the isogenic nature of a cell population over time. The capability to monitor both chronological and reproductive age also makes MIL-CELL potentially useful in studies of cell aging. [ABSTRACT FROM AUTHOR]

Computer simulations using a dynamic model of the skeletal muscle bioenergetic system, involving the Pi-double-threshold mechanism of muscle fatigue, demonstrate that the training-induced increase in  V · O2max, increase in critical power (CP) and acceleration of primary phase II of the  V · O2 on kinetics (decrease in t0.63) is caused by elevated OXPHOS activity acting through a decrease in and slowing of the Pi (inorganic phosphate) rise during the rest-to-work transition. This change leads to attenuation of the reaching by Pi of Pipeak, peak Pi at which exercise is terminated because of fatigue. The delayed (in time and in relation to  V · O2 increase) Pi rise for a given power output (PO) in trained muscle causes Pi to reach Pipeak (in very heavy exercise) after a longer time and at a higher  V · O2; thus, exercise duration is lengthened, and  V · O2max is elevated compared to untrained muscle. The diminished Pi increase during exercise with a given PO can cause Pi to stabilize at a steady state less than Pipeak, and exercise can continue potentially ad infinitum (heavy exercise), instead of rising unceasingly and ultimately reaching Pipeak and causing exercise termination (very heavy exercise). This outcome means that CP rises, as the given PO is now less than, and not greater than CP. Finally, the diminished Pi increase (and other metabolite changes) results in, at a given PO (moderate exercise), the steady state of fluxes (including  V · O2) and metabolites being reached faster; thus, t0.63 is shortened. This effect of elevated OXPHOS activity is possibly somewhat diminished by the training-induced decrease in Pipeak. [ABSTRACT FROM AUTHOR]

Background: The electrical conductivity of trabecular bone at 100 kHz has recently been reported as a good predictor of bone volume fraction. However, quantifying its relationship with free water (or physiological solution) content and the conductivities of its constituents is still difficult. Methods: In this contribution, in silico models inspired by microCT images of trabecular bovine samples were used to build realistic geometries. The finite element method was applied to solve the electrical problem and to robustly fit the conductivity of the constituents to the literature data. The obtained effective electrical conductivity was compared with the Bruggeman three-medium mixture model using a physiological solution, bone marrow and a bone matrix. Results: The values for the physiological solution plus bone marrow (together as one material) and the bone matrix that best captured the bone volume fraction in the two-medium finite element model were σ p s + b m = 298.4 mS/m and σ b = 21.0 mS/m, respectively. Additionally, relatively good results were obtained with the three-medium Bruggeman mixture model, with σ b m = 103 mS/m, σ b = 21.0 mS/m and σ p s = 1200 mS/m. Simple linear relationships between the proportions of constituents depending on bone volume fraction were tested. Degree of anisotropy and fractal dimension do not show detectable changes in effective conductivity. Conclusions: These results provided some useful findings for simulation purposes. First, a higher value for the electrical conductivity of bone marrow has to be used in order to obtain similar values to those of experimental published data. Second, anisotropy is not detectable with conductivity measurements for small trabecular samples (5 mm cube). Finally, the simulations presented here showed relatively good fitting of the Bruggeman mixture model, which would potentially account for the free water content and could rescale the model for whole-bone electrical simulations. [ABSTRACT FROM AUTHOR]

A computer model of the system for generating neutron fluxes at the output of a linear electron accelerator has been developed in the Geant4 and PhysList QGSP BIC HP programming environment. With the help of the model, a number of virtual experiments on 107 primary neutrons were carried out. The dependence of the ratio of the number of neutrons, incident on the detector with a reflector to the number of neutrons without a reflector on the radius of curvature of the hemispherical dome of the reflector is determined, which makes it possible to establish the optimal dimensions of the working area. The energy spectra of neutrons incident on the detector are determined. It has been established that when using a graphite reflector 30⨯ 30 ⨯ 30 cm in size with a radius of curvature of the hemispherical dome of 5 cm, the number of neutrons at the location of the detector increases by 16.9 %, and the neutron background in the accelerator bunker decreases by 2.5 times, which is in good agreement with the real experiment made. Such a decrease in the radiation background, according to sanitary standards, will make it possible to increase the accelerator current by 2.5 times and increase the neutron flux. [ABSTRACT FROM AUTHOR]

An ad hoc network is a transient network that is self-organizing and does not require any infrastructure. Therefore, the majority of its applications are in the field of military work and disaster assistance. Because of wireless connectivity and the ability to organize itself, ad hoc networks are becoming more common. Susceptible to a greater number of breaches or assaults than the conventional system. Blackhole assault is a significant routing disruption attack that a rogue node promotes itself as being capable of. as a step along the way to the final destination. In this research, we simulated a black hole using computer models. Assault in a setting with ad hoc networking, as well as data collection of important features for the purpose of classifying aggressive behaviour. Then, several different approaches to machine learning have been developed. utilized for the classification of information regarding benign and harmful packets. It seems to imply. a novel method for the selection of certain features, the gathering of crucial information, and the intrusion detection in an ad hoc network with the application of machine learning algorithms. [ABSTRACT FROM AUTHOR]

The COVID-19 coronavirus illness is caused by a newly discovered species of coronavirus known as SARS-CoV-2. Since COVID-19 has now expanded across many nations, the World Health Organization (WHO) has designated it a pandemic. Reverse transcription-polymerase chain reaction (RT-PCR) is often used to screen samples of patients showing signs of COVID-19; however, this method is more expensive and takes at least 24 hours to get a positive or negative response. Thus, an immediate and precise method of diagnosis is needed. In this paper, chest X-rays will be utilized through a deep neural network (DNN), based on a convolutional neural network (CNN), to detect COVID-19 infection. Based on their X-rays, those with COVID-19 indications may be categorized as clean, infected with COVID-19 or suffering from pneumonia, according to the suggested CNN network. Sample pieces from every group are used in experiments, and categorization is performed by a CNN. While experimenting, the CNN-derived features were able to generate the maximum training accuracy of 94.82% and validation accuracy of 94.87%. The F1-scores were 97%, 90% and 96%, in clearly categorizing patients afflicted by COVID-19, normal and having pneumonia, respectively. Meanwhile, the recalls are 95%, 91% and 96% for COVID-19, normal and pneumonia, respectively.

This paper presents a method for selecting parameters and analyzing the dynamic characteristics of a under-excitation excitation limiter using a computer model. The parameters are determined using the pole cancellation method for the worst-case operating regime from the perspective of the under-excitation limiter to ensure stability in all operating regimes. The analysis of the dynamic characteristics presented in the paper first obtained the time responses and frequency characteristics of the excitation control system when the limiter is active. Based on these, the values of dynamic performance indicies that indicate the quality of regulation are determined. The paper also provides a brief description of the implementation of the limiter and the computer models used in the analysis.

The purpose of the study was to search for data on the evolution of virtual planning of reconstruction with a fibular graft.Material and Methods. A literature search was carried out in Scopus, RSCI databases in the time interval from 1975 to 2021 using the keywords: “computer”, “surgery”, “facial”, “microsurgery”, “fibula”, “implant”, “fibular flap”, “planning”.Results. Various planning techniques with a description of technical features and estimation of advantages and disadvantages as well as methods of minimizing errors and reducing the time spent on the modeling with an improvement in functional and aesthetic outcomes were discussed. Surgical workflows of robot-assisted osteotomies of a fibular graft were described. Complications, difficulties, and the financial aspect of fibula free flap maxillofacial reconstructions were assessed.Conclusion. Virtual planning of microsurgical reconstructions using a fibular graft reduces operating time. The accuracy of graft fixation is increased and diastases between the osteotomy lines as well as between the native jaw and the graft are decreased. Planning allows surgeons to improve symmetry or keep it in the original form, thus affecting the aesthetic aspect and emotional state of the patient. Virtual planning requires certain financial costs, but the wide range of benefits should convince the professionals to use it as often as possible.

Objective Thermosensitive liposomes (TSL) and other triggered drug delivery systems (DDS) are promising therapeutic strategies for targeted drug delivery. However, successful designs with candidate drugs depend on many variables, including nanoparticle formulation, drug properties, and cancer cell properties. We developed a computational model based on experimental data to predict the potential efficacies of drugs when used with triggered DDS, such as TSL.Methods A computer model based on the Krogh cylinder was developed to predict uptake and cell survival with four anthracyclines when delivered by intravascular triggered DDS (e.g., TSL): doxorubicin (DOX), idarubicin (IDA), pirarubicin (PIR), and aclarubicin (ACLA). We simulated three tumor types derived from SVR angiosarcoma, LLC lung cancer, or SCC-1 oral carcinoma cells. In vitro cellular drug uptake and cytotoxicity data were obtained experimentally and incorporated into the model.Results For all three cell lines, ACLA and IDA had the fastest cell uptake, with slower uptake for DOX and PIR. Cytotoxicity was highest for IDA and lowest for ACLA. The computer model predicted the highest tumor drug uptake for ACLA and IDA, resulting from their rapid cell uptake. Overall, IDA was most effective and produced the lowest tumor survival fraction, with DOX being the second best. Perivascular drug penetration was reduced for drugs with rapid cell uptake, potentially limiting delivery to cancer cells distant from the vasculature.Conclusion Combining simple in vitro experiments with a computer model could provide a powerful screening tool to evaluate the potential efficacy of candidate investigative drugs preceding TSL encapsulation and in vivo studies.

The aim of current research was to establish the relationship between the stress state of the ribbed-ring dome framework and the degree of its bracing. It was assumed that the meridional ribs and rings of the dome framework are made of metal. The framework of the dome consists of 24 ribs and 7 rings. The study was performed for a ribbed-ring dome of spherical shape with a span of 39.3 m and a height of 11.0 m on computer models. The initial computer model of the framework of a ribbed-ring dome made of steel I-beams without bracing has been developed. On the basis of the initial model, additional models were developed for the frameworks with bracing between meridional edges in four, eight cyclically symmetric sectors and in all sectors. Both for the initial model and for all models of the dome framework with bracing, computer calculations were performed for the effect of the load from the own weight of the load-bearing and enclosing structures, and two variants of the snow load. During the calculations, deformations, internal forces and stresses in the meridional ribs, upper and intermediate rings of different models were determined, which were compared with each other. Graphs of changes in deformations of the frame, graphs and diagrams of changes in internal forces and stresses in the meridional ribs, in the upper and intermediate rings of the dome, depending on the degree of bracing in the framework, are obtained. An assessment of the influence of bracing on the stress state of the rib-ring dome frame is performed. The peculiarities of the influence of different coupling schemes on the stressed state of the dome frame are noted.