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By means of molecular dynamics computer simulation, the conformational space of polyampholyte macromolecules with various distributions of the charged groups along the chain is studied. A coarse‐grained model where each monomer unit of the chain is presented as a non‐charged group in the backbone of the macromolecule connected with a charged side pendant is considered. A limiting case of fully charged chains in the isoelectric point is investigated. The oppositely charged monomer units are distributed in various patterns: regular alternating, multiblock, or random sequences. It is found that the chains with random unit distribution adopt much more compacted conformations than the chains with regular distributions with comparable block lengths. Calculating the chain size and its fluctuation along with the spatial density distribution, coil, and globular conformations are distinguished and arranged on the diagrams in terms of chain length, block length, and Bjerrum length. [ABSTRACT FROM AUTHOR]

The paper is devoted to a three-dimensional mesoscale hemodynamic model for simulations of microvascular blood flows at cellular resolution. The focus is on creating a more accurate biomechanical model of red blood cells for further use in models of hemostasis and thrombosis. The presented model effectively and accurately reproduces peculiarities of blood flow under realistic hydrodynamic conditions in arterioles, venules, and capillaries, including the Fahraeus–Lindquist effect and subsequent platelet margination. In addition, shear-dependent platelet aggregation can also be captured using the proposed approach. [ABSTRACT FROM AUTHOR]

Air pollution is currently the most significant environmental factor posing a threat to the health and lives of European residents. It is a key cause of poor health, particularly respiratory and cardiovascular diseases. The primary aim of the study was to numerically determine the impact of the air purifier model's geometry on the distribution of air within a room and to conduct experimental tests on the filtration efficiency and preliminary antibacterial activity of filtration composites. The scope of the work included designing an air purifier model in the form of a pendant lamp and performing computer simulations in Ansys software to identify the optimal shape. The experimental research focused on developing filtration composites consisting of nonwoven fabric with an active hydrosol layer, meltblown nonwovens and a carbon filter. The study results showed that the SMMS composite with 50% thyme and carbon nonwoven exhibited the highest filtration efficiency for both small and large particles. [ABSTRACT FROM AUTHOR]

Between 1925 and 1930, 11 or 12 non‐native mountain goats (Oreamnos americanus) were translocated from Alaska and British Columbia to the foothills of the Olympic Range. By 1970, descendants of these goats had colonized the entire range and concerns about the management of this introduced species developed as damage to alpine soil and vegetation occurred. A series of removals reduced the population from 1175 in 1983 to 389 by 1990, eventually growing to 584 in 2016. We used demographic and genetic data to parameterize a population genetics individual‐based simulation model of the Olympic Range mountain goats. We calibrated the model to replicate the population trajectory for Olympic mountain goats from establishment in the 1920s through the 1983 first census. As expected, modeled population dynamics from 1928 to 1983 mimicked parameter initialization from expanding populations. However, simulated heterozygosity did not align with observations, suggesting a process not accounted for within the simulation model, such as a bottleneck or founder effect. Sensitivity analyses showed changes in annual reproductive rate, juvenile mortality, and adult female mortality influencing population trajectories, but variation in male mortality revealed no changes. Evaluating the population dynamics of the model after removals showed that approximately 80% of the total animals removed during the 1980s needed to be female in order for the observed population estimates to occur. This model has the potential to be used more widely with established or introduced mountain goat populations, as well as to provide an approach for studying other introduced species and their population dynamics. [ABSTRACT FROM AUTHOR]

Thermodynamic equilibria in the Al-Ti-C ternary system are considered as applied to synthesizing titanium carbides in an aluminum medium using the CALPHAD method. A set of calculated isothermal sections of the corresponding state diagram is obtained. Using the results of the thermodynamic analysis of the system, a physically substantiated semi-empirical mathematical computer model was developed that describes the kinetics of TiC synthesis processes in the aluminum medium for the Al-TiC two-phase equilibrium region. Based on the simulation results, it was found that with increased aluminum content in the system, the exothermic burst during TiC synthesis is characterized by lower temperatures and becomes more diffuse in time. The dependence of the dispersity of titanium carbide particles on the aluminum content in the mixture is nonlinear. An increase in the aluminum content slows down the growth of TiC particles. It is shown for the Ti-Al-C system that there is a certain threshold value of the aluminum content (about 30-40%), the excess of which leads to a noticeable dispersion of the sizes of the synthesized titanium carbide grains, which makes it possible to obtain submicron TiC particles. The results obtained are in good agreement with the experimental data. [ABSTRACT FROM AUTHOR]

Disentangling the roles of structural landscape factors and animal movement behaviour can present challenges for practitioners managing landscapes to maintain functional connectivity and achieve conservation goals. We used a landscape genetics approach to combine robust demographic, behavioural and genetic datasets with spatially explicit simulations to evaluate the effects of anthropogenic barriers (dams, culverts) and natural landscape resistance (gradient, elevation) affecting dispersal behaviour, genetic connectivity and genetic structure in a resident population of Westslope Cutthroat Trout (Oncorhynchus clarkii lewisi). Analyses based on 10 years of sampling effort revealed a pattern of restricted dispersal, and population genetics identified discrete population clusters between distal tributaries and the mainstem stream and no structure within the mainstem stream. Demogenetic simulations demonstrated that, for this population, the effects of existing anthropogenic barriers on population structure are redundant with effects of restricted dispersal associated with the underlying environmental resistance. Our approach provides an example of how extensive field sampling combined with landscape genetics can be incorporated into spatially explicit simulation modelling to explore how, together, movement ecology and landscape resistance can be used to inform decisions around restoration and connectivity. [ABSTRACT FROM AUTHOR]

To overcome the significant volume expansion issue encountered by traditional silicon anodes in lithium‐ion batteries, this study employs chemical etching techniques to treat aluminum–silicon alloys of various ratios, successfully preparing three types of porous silicon electrode materials with different pore structures. Through a series of electrochemical tests, this article investigates the role of porous silicon structures in improving electrode performance. The results demonstrate that the porous silicon anodes exhibit superior cycle stability and rate capability compared to traditional solid silicon anodes. This confirms the effectiveness of the porous structure in mitigating the significant volume expansion during the charge and discharge process of silicon materials and in preventing premature electrode failure, thereby significantly enhancing the electrode's cycle life. Remarkably, the porous silicon with a high porosity rate shows exceptionally outstanding performance. Additionally, using computer simulations, this study also models the impact of changes in pore size within the porous silicon material at different states of charge and discharge on the stress distribution at the particle center and surface. These experimental and simulation results jointly provide strong empirical evidence for applying porous silicon materials as high‐performance anode materials for lithium‐ion batteries and offer essential guidance for future stress analysis and electrode design of porous silicon electrode materials. [ABSTRACT FROM AUTHOR]

One of the critical goals of teaching chemistry is to enable learners to gain conceptual understanding. Traditional instruction has often been associated with rote memorisation, resulting in learners failing to explain observed chemical phenomena, make predictions based on acquired concepts, advance convincing arguments, and engage in meaningful problem-solving and critical thinking. Therefore, the study aimed to describe the conceptual understanding of the learners taught Reaction Kinetics using computer simulations supported by the Predict-Observe-Explain strategy. The study was guided by Holme, Luxford, and Brandriet's five categories of conceptual understanding—transfer, translation, problem-solving, prediction, and depth as the conceptual framework. This was a descriptive study in which a case study research approach was used. Five purposively sampled grade 12 learners participated in the study, representing the range of cognitive abilities from a secondary school class of 53 learners. Semi-structured interviews were used to collect data. The responses of the five participants were analysed using the qualitative content analysis. The findings were that most of the learners' responses were in the sound understanding sub-category, some were in the partial understanding sub-category, and a few were in the no understanding sub-category, which made us conclude that computer simulations supported by the Predict-Observe-Explain strategy assisted the learners in conceptual understanding. The learners gained an understanding of most concepts, although their responses in the partial understanding sub-category showed difficulties related to depth, transfer, and translation. These findings are expected to assist chemistry teachers, teacher educators, and curriculum planners in improving learners' conceptual understanding of chemistry. [ABSTRACT FROM AUTHOR]

Abstract Constructivist learning theories consider deep understanding of the content to be the result of engagement in relevant learning activities with appropriate scaffolding that provides the learner with timely and substantive feedback. However, any group of students has a variety of levels of knowledge and cognitive development, which makes providing appropriate individual-level scaffolding and feedback challenging in the classroom. Computer simulations can help meet this challenge by providing technology-enhanced embedded scaffolding and feedback via specific simulation design. The use of computer simulations does not, however, guarantee development of deep science understanding. Careful research-driven design of the simulation and the accompanying teaching structure both play critical roles in achieving the desired learning outcomes. In this paper, we discuss the capabilities of computer simulations and the issues that can impact the learning outcomes when combining technology-enhanced scaffolding and feedback with external teaching structures. We conclude with suggestions of promising research avenues on simulation design and their use in the classroom to help students achieve deep science understanding.

The aim of this study was to understand the interaction between transthyretin (TTR) and halogenated phenols (HPs) including 2,4‐dichlorophenol (DCP), 2,4,6‐trichlorophenol (TCP), pentachlorophenol (PCP), 2‐bromophenol (2‐BP), 2,4‐dibromophenol (DBP) and 2,4,6‐tribromophenol (TBP). Computer simulation and multi‐spectroscopy techniques were used to investigate the interaction. The fluorescence of TTR was found to be quenched through static quenching and non‐radiative energy transfer by HPs, suggesting that the binding process between HPs and TTR was primarily influenced by van der Waals forces and hydrogen bonds. ANS substitution experiments indicated that HPs interacted with TTR at the T4 binding site. Three‐dimensional fluorescence spectra and Fourier transform infrared spectroscopy were used to investigate the conformational and microenvironmental changes of TTR resulting from the interactions with HPs. Additionally, molecular docking and reduced density gradient analysis were used to identify the specific residues and binding forces involved in the interaction between HPs and TTR binding sites. The findings were subsequently validated through quantum chemical analysis. This research integrates state‐of‐the‐art multispectral analytical methodologies with sophisticated computational modeling to introduce an innovative approach for dissecting the interactions between halogenated phenols (HPs) and transthyretin (TTR). This methodology offers a novel avenue for investigating the molecular interplay between HPs and TTR, thereby providing critical insights that are instrumental in assessing the latent toxicity of these compounds. [ABSTRACT FROM AUTHOR]

Cells store triacylglycerol (TAG) within lipid droplets (LDs). A dynamic model describing complete LD formation at the endoplasmic reticulum (ER) membrane does not yet exist. A biochemical‐biophysical model of LD synthesis is proposed. It describes the time‐dependent accumulation of TAG in the ER membrane as the formation of a potential LD (pLD) bounded by spherical caps of the inner and outer monolayers of the membrane. The expansion rate of the pLD depends on the TAG supply, the elastic properties of the ER membrane, and the recruitment of phospholipids (PLs) to the cap‐covering monolayers. Model simulations provided the following insights: (a) Marginal differences in the surface tension of the cap monolayers are sufficient to fully drive the expansion of the pLD towards the cytosol or lumen. (b) Selective reduction of PL supply to the luminal monolayer ensures stable formation of cytosolic LDs, irrespective of variations in the elasto‐mechanical properties of the ER membrane. (c) The rate of TAG supply to the cytosolic monolayer has a major effect on the size and maturation time of LDs but has no significant effect on the TAG export per individual LD. The recruitment of additional PLs to the cap monolayers of pLDs critically controls the budding direction, size, and maturation time of LDs. The ability of cells to acquire additional LD initiation sites appears to be key to coping with acutely high levels of potentially toxic free fatty acids. [ABSTRACT FROM AUTHOR]

Constructivist learning theories consider deep understanding of the content to be the result of engagement in relevant learning activities with appropriate scaffolding that provides the learner with timely and substantive feedback. However, any group of students has a variety of levels of knowledge and cognitive development, which makes providing appropriate individual-level scaffolding and feedback challenging in the classroom. Computer simulations can help meet this challenge by providing technology-enhanced embedded scaffolding and feedback via specific simulation design. The use of computer simulations does not, however, guarantee development of deep science understanding. Careful research-driven design of the simulation and the accompanying teaching structure both play critical roles in achieving the desired learning outcomes. In this paper, we discuss the capabilities of computer simulations and the issues that can impact the learning outcomes when combining technology-enhanced scaffolding and feedback with external teaching structures. We conclude with suggestions of promising research avenues on simulation design and their use in the classroom to help students achieve deep science understanding. [ABSTRACT FROM AUTHOR]

This paper describes the main features and goals of the speculative work in modern sciences that has greatly accelerated since World War II due to the exponential increase in computing power and newly available theoretical and conceptual tools. It points to the long historical strand of speculative philosophical work in symbiosis with the sciences, suggests the reasons for its unexpected neglect in contemporary professional philosophy of science, why it should be a major approach, and why such pursuit is not inevitable. Finally, the paper outlines potential topics, fields, and tools for such collaborative work and argues it is likelier to be more fruitful today than at any point in the past hundred years. [ABSTRACT FROM AUTHOR]

Hill's linear isotropic hyperelastic material models based on the one-parameter (r ) Itskov family of strain tensors (including the Hencky, Pelzer, and Mooney strain tensors generating the H, P, and M material models, respectively) were used to obtain exact solutions of the simple torsion problem for circular cross-section rods from the H, P, and M materials. The "exact" solutions available in the literature for the problem of generalized torsion of cylindrical rods with free edges in the axial direction were analyzed. The objectives of the present study are to develop and implement new formulations of these material models in the commercial MSC.Marc nonlinear FE software and to verify these formulations using the above-mentioned exact solutions. Computer simulations of the simple and generalized torsion of cylindrical specimens were carried out using three material models (H, P, and M) and the standard Mooney–Rivlin model. The results of computer simulations of the resultant moment and the resultant axial force (in the problem of simple torsion) or axial elongation (in the problem of generalized torsion) were compared with exact solutions. For the simple torsion problem, the solutions obtained by the two methods are similar, but for the problem of generalized torsion, these solutions are similar only for sufficiently small values of the torsion parameter. We explain the discrepancy for sufficiently large values of the torsion parameter by the fact that the so-called "exact" solutions cease to be exact because of the assumptions made by other authors in obtaining these solutions. We assume that for all values of the torsion parameter, our numerical solutions are close to the true exact solutions. Computer simulations showed that the Pelzer material model is similar in performance to the Mooney–Rivlin model. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the financial feasibility of rainwater harvesting and greywater reuse in a multifamily building located in Florianópolis, Brazil. A building, consisting of two blocks with 60 flats each, was chosen to obtain data about the number of residents, building characteristics, potable water consumption, and rainwater and greywater demands (obtained by means of questionnaires and water measurements). The financial feasibility analyses considered rainwater and greywater systems separately and together. The impact on the urban stormwater drainage system was evaluated through the reduction of stormwater runoff. The energy consumption in the operational phase of each system was estimated through the amount of energy consumed by the motor pumps to supply one cubic meter of water. The potential for potable water savings through the use of rainwater—that supplies water for washing machines—was approximately 6.9%. The potential for potable water savings through the use of greywater—that supplies water to toilets—was approximately 5.7%. Both systems were feasible. The payback period for rainwater harvesting systems ranged from 57 to 76 months. For greywater systems, the payback period ranged from 127 to 159 months. When considering both systems working together, the payback period ranged from 89 to 132 months. The rainwater harvesting system can reduce 11.8% the stormwater volume destined to the urban stormwater drainage system in relation to the current contribution volume. Energy consumption was approximately 0.56 kWh/m3 of treated water for the rainwater harvesting system and 0.89 kWh/m3 of treated water for the greywater system. Rainwater and greywater were considered economically feasible, especially for higher inflation scenarios. Furthermore, such systems are interesting alternatives in terms of impacts considering urban drainage and energy consumption. [ABSTRACT FROM AUTHOR]

Background: Clinical and experimental data on the cardiac effects of acute hypernatremia are scarce and inconsistent. We aimed to determine and understand the effects of different levels of acute hypernatremia on the human ventricular action potential. Methods: We performed computer simulations using two different, very comprehensive models of the electrical activity of a single human ventricular cardiomyocyte, i.e., the Tomek-Rodriguez model following the O'Hara-Rudy dynamic (ORd) model and the Bartolucci-Passini-Severi model as published in 2020 (known as the ToR-ORd and BPS2020 models, respectively). Mild to extreme levels of hypernatremia were introduced into each model based on experimental data on the effects of hypernatremia on cell volume and individual ion currents. Results: In both models, we observed an increase in the intracellular sodium and potassium concentrations, an increase in the peak amplitude of the intracellular calcium concentration, a hyperpolarization of the resting membrane potential, a prolongation of the action potential, an increase in the maximum upstroke velocity, and an increase in the threshold stimulus current at all levels of hypernatremia and all stimulus rates tested. The magnitude of all of these effects was relatively small in the case of mild to severe hypernatremia but substantial in the case of extreme hypernatremia. The effects on the action potential were related to an increase in the sodium-potassium pump current, an increase in the sodium-calcium exchange current, a decrease in the rapid and slow delayed rectifier potassium currents, and an increase in the fast and late sodium currents. Conclusions: The effects of mild to severe hypernatremia on the electrical activity of human ventricular cardiomyocytes are relatively small. In the case of extreme hypernatremia, the effects are more pronounced, especially regarding the increase in threshold stimulus current. [ABSTRACT FROM AUTHOR]

The research shows how to use swarming algorithms to rebuild the heat transfer coefficient, especially in regard to the continuous border condition. The authors utilized their application software to do numerical computations, employing classical variants of swarm algorithms. The numerical calculations employed a functional determining error to assess the accuracy of the estimated result. The functional minimization was conducted with the swarm algorithms (especially ABC and ACO). The geometry analyzed in this study consisted of a square shape referred to as the cast, enclosed within another square shape known as the casting mold. These two squares were separated by a layer facilitating heat conduction, characterized by the coefficient κ. The coefficient of the thermally conductive layer was recalibrated utilizing swarm methods within the range of 900 - 1500 [W/m^2K] and subsequently compared to a predetermined reference value. A finite element mesh consisting of 576 nodes was used for the calculations. The study involved simulations with populations of 5, 10, 15, and 20 individuals. Furthermore, each scenario also took into account noise of 0%, 2%, and 5% of the reference values. Results make evident the reconstructed value of the κ coefficient, cooling curves, and temperatures for the ABC and ACO algorithms are physically correct. The consequences indicate a notable level of satisfaction and strong concurrence with the anticipated of the κ parameter values. The results from the numerical simulations demonstrate considerable promise for applying artificial intelligence algorithms in optimizing production processes, analyzing data, and facilitating data-driven decision-making.

Paper-based microfluidics has emerged as a promising field with diverse applications ranging from medical diagnostics to environmental monitoring. Despite significant progress in research and development, the translation of paper-based prototypes into practical end-user devices remains limited. This limitation stems from challenges related to devices not being sufficiently portable and autonomous, which paper-based microfluidics is expected to overcome. Yet for this purpose, we note the lack of comprehensive numerical modeling tools capable of simulating the intricate physicochemical phenomena involved in order to optimize the development process; hence, in this study, we introduce porousMicroTransport, a novel simulation package integrated with the open-source platform OpenFOAM®, designed to address these challenges. porousMicroTransport offers efficient solvers for fluid flow and transport phenomena in microfluidic porous media, including capillarity models and (bio)chemical reactions. Moreover, under horizontal flow conditions, porousMicroTransport application field can be extended to any porous media. We demonstrate the software’s effectiveness in two example cases, showcasing its ability to accurately reproduce complex phenomena involved in paper-based devices. By virtue of being an easy-to-use and computationally efficient tool, porousMicroTransport facilitates the design and optimization of devices, potentially enabling more devices to meet the WHO’s REASSURED criteria for point-of-care testing. We anticipate that this tool will accelerate the development and deployment of robust and portable diagnostic devices, bridging the gap between research and practical applications.

This study investigates how varying cell size affects the mechanical behaviour of photopolymer Triply Periodic Minimal Surfaces (TPMS) under different deformation rates. Diamond, Gyroid, and Primitive TPMS structures with spatially graded cell sizes were tested. Quasi-static experiments measured boundary forces, representing material behaviour, inertia, and deformation mechanisms. Separate studies explored the base material's behaviour and its response to strain rate, revealing a strength increase with rising strain rate. Ten compression tests identified a critical strain rate of 0.7 s−1 for "Grey Pro" material, indicating a shift in failure susceptibility. X-ray tomography, camera recording, and image correlation techniques observed cell connectivity and non-uniform deformation in TPMS structures. Regions exceeding the critical rate fractured earlier. In Primitive structures, stiffness differences caused collapse after densification of smaller cells at lower rates. The study found increasing collapse initiation stress, plateau stress, densification strain, and specific energy absorption with higher deformation rates below the critical rate for all TPMS structures. However, cell-size graded Primitive structures showed a significant reduction in plateau and specific energy absorption at a 500 mm/min rate. [ABSTRACT FROM AUTHOR]

This article discusses the notions of 'epistemic opacity' -- referred to here as 'weak epistemic opacity' -- and 'essential epistemic opacity' originally proposed by Paul Humphreys, and defends the idea that epistemic opacity, in general, should be taken as a concept coming in degrees. This approach helps to put into perspective and better understand the close relationship between the notion of epistemic opacity and concrete scientific practices. [ABSTRACT FROM AUTHOR]

The paper presents research on identifying a biomechanical parameter from a theoretical model of changes during osteoarthritis. In vitro experiments were carried out on quasi-3D chondrocyte cultures seeded on corn-starch hydrogel materials and subjected to mechanical stress on a designed and constructed stand. The results were adapted to a mathematical model and calculated on a simplified two-dimensional specimen. Numerical simulations have been performed to illustrate the growth of bone spurs. The observed changes of variables which determine osteophytes are qualitative and more correlated to the real-life observations. [ABSTRACT FROM AUTHOR]

In injured arteries, platelets adhere to the subendothelium and initiate the coagulation process. They recruit other platelets and form a plug that stops blood leakage. The formation of the platelet plug depends on platelet activation, a process that is regulated by intracellular calcium signaling. Using an improved version of a previous multiscale model, we study the effects of changes in calcium signaling on thrombus growth. This model utilizes the immersed boundary method to capture the interplay between platelets and the flow. Each platelet can attach to other platelets, become activated, express proteins on its surface, detach, and/or become non-adhesive. Platelet activation is captured through a specific calcium signaling model that is solved at the intracellular level, which considers calcium activation by agonists and contacts. Simulations reveal a contact-dependent activation threshold necessary for the formation of the thrombus core. Next, we evaluate the effect of knocking out the P2Y and PAR receptor families. Further, we show that blocking P2Y receptors reduces platelet numbers in the shell while slightly increasing the core size. An analysis of the contribution of P2Y and PAR activation to intraplatelet calcium signaling reveals that each of the ADP and thrombin agonists promotes the activation of platelets in different regions of the thrombus. Finally, the model predicts that the heterogeneity in platelet size reduces the overall number of platelets recruited by the thrombus. The presented framework can be readily used to study the effect of antiplatelet therapy under different physiological and pathological blood flow, platelet count, and activation conditions. [ABSTRACT FROM AUTHOR]

This work introduces X‐Ray Calc (XRC), an open‐source software package designed to simulate X‐ray reflectivity (XRR) and address the inverse problem of reconstructing film structures on the basis of measured XRR curves. XRC features a user‐friendly graphical interface that facilitates interactive simulation and reconstruction. The software employs a recursive approach based on the Fresnel equations to calculate XRR and incorporates specialized tools for modeling periodic multilayer structures. This article presents the latest version of the X‐Ray Calc software (XRC3), with notable improvements. These enhancements encompass an automatic fitting capability for XRR curves utilizing a modified flight particle swarm optimization algorithm. A novel cost function was also developed specifically for fitting XRR curves of periodic structures. Furthermore, the overall user experience has been enhanced by developing a new single‐window interface. [ABSTRACT FROM AUTHOR]

Spectral line shapes code in plasmas (SLSPs) code comparison workshops have been organized in the last decade with the aim of comparing the spectra obtained with independently developed analytical and numerical models. Here, we consider the simultaneous effect of a plasma microfield and a periodic electric field on the hydrogen lines Lyman-α, Lyman-β, Balmer-α, and Balmer-β for plasma conditions where the Stark effect usually dominates line broadening. [ABSTRACT FROM AUTHOR]

Cyclic dinucleotides (CDNs) are cyclic molecules consisting of two nucleoside monophosphates linked by two phosphodiester bonds, which act as a second messenger and bind to the interferon gene stimulating factor (STING) to activate the downstream signaling pathway and ultimately induce interferon secretion, initiating an anti-infective immune response. Cyclic dinucleotides and their analogs are lead compounds in the immunotherapy of infectious diseases and tumors, as well as immune adjuvants with promising applications. Many agonists of pathogen recognition receptors have been developed as effective adjuvants to optimize vaccine immunogenicity and efficacy. In this work, the binding mechanism of human-derived interferon gene-stimulating protein and its isoforms with cyclic dinucleotides and their analogs was theoretically investigated using computer simulations and combined with experimental results in the hope of providing guidance for the subsequent synthesis of cyclic dinucleotide analogs. [ABSTRACT FROM AUTHOR]

Background: Simulated computed tomography (CT) images allow for knowledge of the underlying ground truth and for easy variation of imaging conditions, making them ideal for testing and optimization of new applications or algorithms. However, simulating all processes that affect CT images can result in simulations that are demanding in terms of processing time and computer memory. Therefore, it is of interest to determine how much the simulation can be simplified while still achieving realistic results. Purpose: To develop a scanner‐specific CT simulation using physics‐based simulations for the position‐dependent effects and shift‐invariant image corruption methods for the detector effects. And to investigate the impact on image realism of introducing simplifications in the simulation process that lead to faster and less memory‐demanding simulations. Methods: To make the simulator realistic and scanner‐specific, the spatial resolution and noise characteristics, and the exposure‐to‐detector output relationship of a clinical CT system were determined. The simulator includes a finite focal spot size, raytracing of the digital phantom, gantry rotation during projection acquisition, and finite detector element size. Previously published spectral models were used to model the spectrum for the given tube voltage. The integrated energy at each element of the detector was calculated using the Beer–Lambert law. The resulting angular projections were subsequently corrupted by the detector modulation transfer function (MTF), and by addition of noise according to the noise power spectrum (NPS) and signal mean‐variance relationship, which were measured for different scanner settings. The simulated sinograms were reconstructed on the clinical CT system and compared to real CT images in terms of CT numbers, noise magnitude using the standard deviation, noise frequency content using the NPS, and spatial resolution using the MTF throughout the field of view (FOV). The CT numbers were validated using a multi‐energy CT phantom, the noise magnitude and frequency were validated with a water phantom, and the spatial resolution was validated with a tungsten wire. These metrics were compared at multiple scanner settings, and locations in the FOV. Once validated, the simulation was simplified by reducing the level of subsampling of the focal spot area, rotation and of detector pixel size, and the changes in MTFs were analyzed. Results: The average relative errors for spatial resolution within and across image slices, noise magnitude, and noise frequency content within and across slices were 3.4%, 3.3%, 4.9%, 3.9%, and 6.2%, respectively. The average absolute difference in CT numbers was 10.2 HU and the maximum was 22.5 HU. The simulation simplification showed that all subsampling can be avoided, except for angular, while the error in frequency at 10% MTF would be maximum 16.3%. Conclusion: The simulation of a scanner‐specific CT allows for the generation of realistic CT images by combining physics‐based simulations for the position‐dependent effects and image‐corruption methods for the shift‐invariant ones. Together with the available ground truth of the digital phantom, it results in a useful tool to perform quantitative analysis of reconstruction or post‐processing algorithms. Some simulation simplifications allow for reduced time and computer power requirements with minimal loss of realism. [ABSTRACT FROM AUTHOR]

This study explores the pedagogical approach in the first-year Applied Physics course of Engineering degrees at the University of A Corufia. Employing a comprehensive strategy, educators developed simulations to address student weaknesses identified in pre-tests. The research aims to bridge gaps by outlining objectives, elucidating methodology, and presenting tools used. Utilizing a quasi-experimental design over eight academic years. the investigation incorporates computer simulations, pre-tests, post-tests, and final exams. The primary objective is to improve engineering education through innovative methods, focusing on core principles like friction. thermodynamics, fluid rotation, and electromagnetic forces. Outcomes are showcased through various assessments. including general satisfaction surveys and specific questionnaires. Emphasizing distinctiveness, marked by inventive pedagogy, rigorous data analysis, and a sustained cohort study, the study contributes to ongoing discussions on engineering education enhancement. Ultimately, it empowers students for practical applications. [ABSTRACT FROM AUTHOR]

The research shows a novel approach leveraging swarm algorithms, the artificial bee colony (ABC) and ant colony optimization (ACO), to rebuild the heat transfer coefficient, especially for the continuous border condition. The authors utilized their application software to do numerical computations, employing classical variants of swarm algorithms. The numerical calculations employed a functional determining error to assess the accuracy of the estimated result. The coefficient of the thermally conductive layer was recalibrated utilizing swarm methods within the range of 900-1500 W/m²K and subsequently compared to a predetermined reference value. A finite element mesh consisting of 576 nodes was used for the calculations. The study involved simulations with populations of 5, 10, 15, and 20 individuals. Furthermore, each scenario also considered noise of 0%, 2%, and 5% of the reference values. The results make it evident that the reconstructed values of the kappa coefficient, cooling curves, and temperatures for the ABC and ACO algorithms are physically correct. The consequences indicate a notable level of satisfaction and strong concurrence with the anticipated κ parameter values. The results from the numerical simulations demonstrate considerable promise for applying artificial intelligence algorithms to optimize production processes, analyze data, and facilitate data-driven decision-making. This contribution not only underscores the effectiveness of swarm intelligence in engineering applications but also opens new avenues for research in thermal process optimization. [ABSTRACT FROM AUTHOR]

In contrast with for-profit companies, many "multiaudience" organizations, such as universities, hospitals, and nonprofits, receive revenues not just from customers but from third-party funders. This distinction is most stark in donative nonprofits that receive all of their funding from noncustomers and have long been perceived to underperform because of persistent underinvestment in organizational capabilities. In this paper, we explore how the need to manage funder perceptions influences how managers allocate resources to investment in organizational capabilities versus programmatic spending. We develop a model of capability dynamics based on fieldwork with six nonprofit organizations that incorporates the mechanism of reputation management. We argue that difficulties communicating the impact of nonprofits to donors often leads managers to instead focus on the amount of work being done, creating a bias toward programmatic spending. Analyzing our model, we show that a capability tipping threshold exists: for nonprofits with low capabilities, it is boundedly rational for managers to underinvest in organizational capabilities in order to manage donor perceptions even when this practice is known to limit performance. Our findings suggest that building high-performance nonprofits requires coordinated action between managers and donors to allow capability investments to accumulate. Counterintuitively, deliberately restraining programmatic expenditure (i.e., serving fewer recipients) while the organization builds its capabilities may be the best strategy for nonprofits to achieve sustained high performance and impact in the long run. Supplemental Material: The online appendix is available at https://doi.org/10.1287/orsc.2022.1579. [ABSTRACT FROM AUTHOR]

This work contributes to the comprehension of Bayes’ theorem inclusive Bayesian probabilities and Bayesian inferencing within the framework of STEM (Science, Technology, Engineering, Arts, and Mathematics) and cognitive learning w.r.t Bloom’s taxonomy (BT). Bayes’ theorem is taken as a crucial statistical instrument employed in the development of intelligent systems and the management of risks, commonly utilized by engineers for tasks in machine learning and managerial decision-making. The fundamental concept behind Bayes’ theorem revolves around comprehending the degree of truth within the confines of an explicit perspective. This involves partitioning the entire sample space of possible evidence and utilizing the subset containing the relevant perspective to estimate the uncertainty of an event or the reliability of a model. However, it is often found difficult for students to understand Bayes’ theorem to the level of applying it to real-world problems. Considering this, the proposed learning method in this paper elucidated the acquisition of Bayes’ mathematical formulation by leveraging computational thinking, leading to the development of a computational model. The proposed model is named the Bayesian Computational Learning Model (BCLM). Subsequently, we have probed the utility of BCLM in the design and plan of learning activities, coherent to the STEM paradigm and BT cognitive learning hierarchy.

Air pollution is currently the most significant environmental factor posing a threat to the health and lives of European residents. It is a key cause of poor health, particularly respiratory and cardiovascular diseases. The primary aim of the study was to numerically determine the impact of the air purifier model’s geometry on the distribution of air within a room and to conduct experimental tests on the filtration efficiency and preliminary antibacterial activity of filtration composites. The scope of the work included designing an air purifier model in the form of a pendant lamp and performing computer simulations in Ansys software to identify the optimal shape. The experimental research focused on developing filtration composites consisting of nonwoven fabric with an active hydrosol layer, meltblown nonwovens and a carbon filter. The study results showed that the SMMS composite with 50% thyme and carbon nonwoven exhibited the highest filtration efficiency for both small and large particles.

This study focuses on the ideal etching of defective MAX phases in a mechanical exfoliation process to produce vanadium-based MXenes. Two-dimensional MXenes exhibit high structural stability and excellent electrical conductivity, and can be applied as electrode materials. Mechanical exfoliation can be facilitated by modifying the vacancy in the V 2 AlC MAX phase, which makes etching challenging. We report the effects of M (vanadium), A (aluminum), and X (carbon) vacancies on the mechanical behavior of V 2 AlC via ab initio calculations. To this end, the anisotropic mechanical properties and strain–stress curves were calculated for MAX phases with different vacancies (x = 0.08, which corresponds to 8.33 at.%). The presence of vanadium vacancies significantly deteriorated the structural and mechanical properties compared to those of aluminum and carbon vacancies. Thus, it was confirmed that vanadium vacancies had a significant effect on the mechanical exfoliation of the MAX phases. These findings provide further insights into the design of MXenes. [ABSTRACT FROM AUTHOR]

Bio-based semicrystalline polylactide (PLA) has a growing value as a substitute for fossil-based polyesters in technical applications and as a biocompatible material in medicine. The complexity of the behavior of PLA, determined by the presence of different stereoisomers, the role of electrostatic interactions, and its slow crystallization rate, makes computer simulations an important tool to discover new approaches to control the properties of PLA-based materials. The goal of this review is to summarize the efforts to simulate PLA materials with different levels of detail, including the quantum mechanical approach, all-atom modeling, and coarse-grained particle models. We focus on the validation of the models and the ways to cross-check the results with other simulation and experimental data. Special attention is devoted to the simulations of PLA in the presence of water, which provide insights into molecular mechanisms of hydrolytic degradation of PLA, especially at the initial stage, when the structural changes can not yet be detected by experimental methods. Ultimately, the selection of the appropriate simulation methods can facilitate material design, by combining the throughput and level of detail necessary for the job. [ABSTRACT FROM AUTHOR]

The intensive development of nanodevices acting as two-state systems has motivated the search for nanoscale molecular structures whose long-term conformational dynamics are similar to the dynamics of bistable mechanical systems such as Euler arches and Duffing oscillators. Collective synchrony in bistable dynamics of molecular-sized systems has attracted immense attention as a potential pathway to amplify the output signals of molecular nanodevices. Recently, pyridine-furan oligomers of helical shape that are a few nanometers in size and exhibit bistable dynamics similar to a Duffing oscillator have been identified through molecular dynamics simulations. In this article, we present the case of dynamical synchronization of these bistable systems. We show that two pyridine-furan springs connected by a rigid oligomeric bridge spontaneously synchronize vibrations and stochastic resonance enhances the synchronization effect. [ABSTRACT FROM AUTHOR]

Objectives: A virtual clinical trial (VCT) method is proposed to determine the limit of calcification detection in tomosynthesis. Methods: Breast anatomy, focal findings, image acquisition, and interpretation (n = 14 readers) were simulated using screening data (n = 660 patients). Calcifications (0.2–0.4 mm3) were inserted into virtual breast phantoms. Digital breast tomosynthesis (DBT) acquisitions were simulated assuming various acquisition geometries: source motion (continuous and step-and-shoot), detector element size (140 and 70 µm), and reconstructed voxel size (35–140 µm). VCT results were estimated using multiple-reader multiple-case analyses and d' statistics. Signal-to-noise (SNR) analyses were also performed using BR3D phantoms. Results: Source motion and reconstructed voxel size demonstrated significant changes in the performance of imaging systems. Acquisition geometries that use 70 µm reconstruction voxel size and step-and-shoot motion significantly improved calcification detection. Comparing 70 with 100 µm reconstructed voxel size for step-and-shoot, the ΔAUC was 0.0558 (0.0647) and d' ratio was 1.27 (1.29) for 140 µm (70 µm) detector element size. Comparing step-and-shoot with a continuous motion for a 70 µm reconstructed voxel size, the ΔAUC was 0.0863 (0.0434) and the d' ratio was 1.40 (1.19) for 140 µm (70 µm) detector element. Small detector element sizes (e.g., 70 µm) did not significantly improve detection. The SNR results with the BR3D phantom show that calcification detection is dependent upon reconstructed voxel size and detector element size, supporting VCT results with comparable agreement (ratios: d' = 1.16 ± 0.11, SNR = 1.34 ± 0.13). Conclusion: DBT acquisition geometries that use super-resolution (smaller reconstructed voxels than the detector element size) combined with step-and-shoot motion have the potential to improve the detection of calcifications. Clinical relevance: Calcifications may not always be discernable in tomosynthesis because of differences in acquisition and reconstruction methods. VCTs can identify strategies to optimize acquisition and reconstruction parameters for calcification detection in tomosynthesis, most notably through super-resolution in the reconstruction. Key Points: • Super-resolution improves calcification detection and SNR in tomosynthesis; specifically, with the use of smaller reconstruction voxels. • Calcification detection using step-and-shoot motion is superior to that using continuous tube motion. • A detector element size of 70 µm does not provide better detection than 140 µm for small calcifications at the threshold of detectability. [ABSTRACT FROM AUTHOR]

The metaphor of an organization as a garbage can is often invoked as a playful insult. However, as was recognized early on by management theorists studying garbage can ideas, the unpredictability arising from garbage can decision making has the potential to be adaptively rational for organizations facing complex task environments. The chaos produced by preference conflict and fluid participation in collective decision making can aid in search by enabling organizations to escape local performance peaks or competency traps. The decades-old hypothesis that conflict and chaos could promote adaptively rational search, however, has largely been overlooked in research on organizational design. This paper uses an agent-based model to evaluate these competing views and, in the process, identify conditions under which garbage can decision making is adaptively rational for executives searching for high-quality strategies. I show that the biased and chaotic outcomes that emerge as a result of garbage can decision making—the very features of garbage cans that lead them to be perceived to be dysfunctional—can facilitate short-term exploitation and long-term exploration of uncertain technical landscapes when organizations engage in serial judgment of local alternatives if internal conflict over desired outcomes is not too extreme. I conclude that decision-making routines that encourage chaotic conflict are robust to bounded rationality and complex task uncertainty and thus should be included in the organizational designer's portfolio. Supplemental Material: The online supplement is available at https://doi.org/10.1287/orsc.2023.1662. [ABSTRACT FROM AUTHOR]

In this communication, we describe the application of Boltzmann kinetic equations for modeling massive electronic excitation in a silicon nanocrystal film after its irradiation with intense femtosecond hard X-ray pulses. This analysis was inspired by an experiment recently performed at the X-ray free-electron laser facility SACLA, which measured a significant reduction in atomic scattering factors triggered by an X-ray pulse of the intensity ∼ 10 19 W/cm 2 , occurring on a timescale comparable with the X-ray pulse duration (6 fs full width at half maximum). We show that a Boltzmann kinetic equation solver can accurately follow the details of the electronic excitation in silicon atoms caused by such a hard X-ray pulse, yielding predictions in very good agreement with the experimental data. [ABSTRACT FROM AUTHOR]

This study presents an econophysics based approach to the study of lotteries. By treating lotteries as complex systems we analyse the guiding dynamics of real-world lotteries. We found that the growth of the jackpot, that can be won, between two successive draws is proportional to its preceding value. This growth is best described as a linear function with two parameters a and b reflecting foundational player pool sales and the excitement generated by the current jackpot respectively. A computer simulation considering additional parameters (such as the price of a ticket: s, and the format of the lottery: p) is used to study the statistical features of simulated lotteries covering a vast parameter space. This approach enables us to construct a detailed map of how various parameters influence lottery behaviour by examining the statistical characteristics of the simulated lotteries. The findings emphasize the need for thoughtful pricing strategies in real-world lotteries and suggest that simulations can assist organizers in making informed decisions. [ABSTRACT FROM AUTHOR]

Co-adsorption of multi-components in ZrCo-based hydrogen storage materials can lead to a number of synergistic effects, such as the modification of adsorption sites, and further worsen the hydrogen storage capability. In this work, we explore the co-adsorption of H and CO on the ZrCo(110) surface and find that the molecular CO can be adsorbed on the clean alloy surface and thus decrease the hydrogen storage ability of the alloy. Moreover, CO occupies the adsorption site of H and therefore prevents the adsorption and diffusion into the interior of the lattice. Fortunately, the Hf dopant reduces the number of adsorption sites of the CO molecule and inhibits the formation of carbides to a certain extent. In addition, the partial density of states (PDOS) result shows that there is almost no interaction between the s orbital of H and the s orbital of Co on the pure surface of pre-adsorbed CO, while on the Hf-doped surface of pre-adsorbed CO, the s orbital of H overlapped greatly with the s orbital of Co, indicating that Hf doping inhibits CO toxicity in the interaction between H and the surface. Hence, the doping of Hf has the effect of giving resistance to CO toxicity and is conducive to the adsorption of H. [ABSTRACT FROM AUTHOR]

Normal log lengths in Norway are 3-6 m (NL), but occasionally there is a demand for short timber with a 2.5 m log length (ST). There are concerns that ST could reduce the forwarders' productivity. Six type stands were created based on harvester data. Different assortment distributions, conditions, and forwarders were simulated in each type stand. It was found that an additional ST assortment almost always decreased productivity (from -15.5 to +4%). Increased forwarding distance (m), more difficult driving conditions, and increased log concentration [m3.(100 m strip road)-1] decreased the productivity difference between sites with ST and NL and sites with only NL. Increased forwarder size increased the productivity difference between sites with ST and NL and sites with only NL. It is possible to load two stacks of ST on some forwarders. Such loading was more productive than loading one stack on longer forwarding distances, while the opposite was the case on short distances. However, loading two stacks of ST can lead to overloading.

This article, titled "Editorial: Computational and experimental insights in proton and ion translocating bioenergetic systems," discusses the use of computational and experimental approaches to understand the molecular mechanisms of bioenergetic systems. Specifically, it focuses on proteins that perform redox-coupled proton pumping, which play a crucial role in energy transduction in living organisms. The article highlights recent experimental findings and computational studies that have improved our understanding of these systems, particularly in relation to cytochrome c oxidase and cytochrome bd-type enzymes. The authors also discuss the use of computational approaches, such as molecular dynamics simulations and quantum mechanics-based calculations, to gain molecular insights into enzyme mechanisms. Overall, this article provides valuable information for researchers interested in bioenergetics and proton translocation. [Extracted from the article]

A mathematical model of the spatial distribution of the radiation flux in a multimode Hermite-Gaussian beam is proposed. In this model, the spatial distribution of the radiation flux is described by rays with radiation fluxes strung on them. A feature of the proposed model is that the radiation fluxes strung on the beams are added algebraically.