Realistic Model Research Articles

Development of an effective simulation model for evaluating smoke leakage during laparoscopic surgery.

The leakage of surgical gas and smoke from the peritoneum during laparoscopy may release noxious aerosols, including potential carcinogens, viruses and other contaminants, into the operating theatre, especially into the breathing zone of the surgical team. Reliable and realistic models and methods that develop and detect surgical smoke in simulated settings are necessary to effectively test devices and strategies intended to reduce such leaks. Here, we report a novel high-fidelity laparoscopic smoke model with innovative imaging methods applicable to the theatre setting, followed by an assessment of the usefulness of commercial laparoscopic trocars and smoke evacuation methods in mitigating gas leaks. Various smoke production methods (including tissue cautery and industrial smoke machinery) and detection methods (including schlieren imaging, laser videography, intraperitoneal video recording, and an aerosol detector) were tested, with the smoke machine model proving the most reproducible. Schlieren imaging, laser videography and intraperitoneal video recording were all effective methods of surgical smoke quantification. Following model establishment, laparoscopic trocars (VersaOneTM, Medtronic, Ireland) and smoke evacuation systems (EVA15 smart insufflator and evacuator, Palliare, PlumePort Activ® Smoke Filtration Device, Conmed and ValleylabTM Smoke Evacuation System, Medtronic) were examined in a standardized way with performance assessment by three surgeons independently using a boutique scoring system. The EVA15 outperformed other smoke systems in clearing surgical smoke from the operative field and in reducing trocar leaks during instrumentation. This method of simulated surgical smoke production and assessment can benchmark other laparoscopic equipment regarding smoke management strategies in a similar fashion.

Baroclinic instability‐induced intensification of phytoplankton blooms at submesoscales in eutrophic frontal regions

AbstractOff‐coast phytoplankton blooms occur frequently in the frontal region of the eutrophic Taiwan Strait during the northeasterly monsoon relaxation period, as consistently revealed by extensive cruise and satellite observations. Realistic model simulations have shown that restratification by frontal baroclinic instability (BCI) plays a crucial role in triggering blooms under nutrient‐rich conditions. This study deciphered the distinct contributions of submesoscale and mesoscale BCIs to bloom development using sensitivity tests of an idealized model of the Taiwan Strait featuring an intense alongshore front with ample nutrients. In three‐dimensional fine simulations with both submesoscale and mesoscale BCIs present, blooms were triggered by the cessation of a down‐front wind. Chlorophyll a was higher in submesoscale front regions than in mesoscale regions, primarily because of the higher upper‐ocean stability resulting from more effective restratification by submesoscale BCI. In three‐dimensional coarse simulations, mesoscale BCI led to relatively lower upper‐ocean stability and weaker blooms following wind relaxation, consistent with those in mesoscale regions in corresponding three‐dimensional fine simulations. In two‐dimensional simulations without submesoscale and mesoscale BCIs, blooms could not be triggered despite the cessation of a down‐front wind, primarily because of the absence of significant near‐surface restratification by BCIs. Furthermore, although symmetric instability was present in two‐dimensional fine simulations, its contribution to blooms was limited because of its minimal restratification effect. These results show that BCIs play the predominant role in triggering off‐coast blooms in eutrophic coastal front regions such as the Taiwan Strait.

COCOMO2: A Coarse-Grained Model for Interacting Folded and Disordered Proteins.

Biomolecular interactions are essential in many biological processes, including complex formation and phase separation processes. Coarse-grained computational models are especially valuable for studying such processes via simulation. Here, we present COCOMO2, an updated residue-based coarse-grained model that extends its applicability from intrinsically disordered peptides to folded proteins. This is accomplished with the introduction of a surface exposure scaling factor, which adjusts interaction strengths based on solvent accessibility, to enable the more realistic modeling of interactions involving folded domains without additional computational costs. COCOMO2 was parametrized directly with solubility and phase separation data to improve its performance on predicting concentration-dependent phase separation for a broader range of biomolecular systems compared to the original version. COCOMO2 enables new applications including the study of condensates that involve IDPs together with folded domains and the study of complex assembly processes. COCOMO2 also provides an expanded foundation for the development of multiscale approaches for modeling biomolecular interactions that span from residue-level to atomistic resolution.

On the absence of weak solutions for a sequential time-fractional Klein–Gordon equation with quadratic nonlinearity

The Klein–Gordon equation with quadratic nonlinearity is frequently used to model various problems of physics. On the other hand, it was shown that in many situations, the use of fractional derivatives instead of ordinary derivatives provides more realistic models. In this work, a one-dimensional sequential time-fractional Klein–Gordon equation posed on a bounded interval, subject to certain initial and boundary conditions, is investigated. The fractional derivatives are considered in the Caputo sense and a weight function [Formula: see text] is allowed in front of the quadratic nonlinearity. Namely, we first establish general sufficient conditions for the nonexistence of solutions. Next, some particular cases of weight functions [Formula: see text] are discussed. In our approach, we make use of the test function method. This method requires an appropriate choice of a family of test functions. In this paper, we make a judicious choice of test functions taking into consideration the nonlocal property of the Caputo fractional derivative, the initial and boundary conditions, and the geometry of the domain.

Prolonged exposure to heat enhances mosquito tolerance to viral infection

How and to what extent mosquito-virus interaction is influenced by climate change is a complex question of ecological and epidemiological relevance. We worked at the intersection between thermal biology and vector immunology and studied shifts in tolerance and resistance to the cell fusing agent virus (CFAV), a prominent component of the mosquito virome known to contribute to shaping mosquito vector competence, in warm-acclimated and warm-evolved Aedes albopictus mosquitoes. We show that the length of the thermal challenge influences the outcome of the infection with warm-evolved mosquitoes being more tolerant to CFAV infection, while warm-acclimated mosquitoes being more resistant and suffering from extensive fitness costs. These results highlight the importance of considering fluctuations in vector immunity in relation to the length of a thermal challenge to understand natural variation in vector response to viruses and frame realistic transmission models.

Assessing potential reductions of agricultural GHG in countries with different land productivities: Long-term integrated efficiency in DEA hybrid meta-frontier model.

Globally, the agricultural sector is responsible for the emission of ca. 9.3 gigatons of CO2 equivalent annually. A realistic efficiency model orientation, considering agricultural policy objectives in a given region of the world, is a crucial premise for finding the optimal path for achieving global targets of emission reduction. The main objective of this article is to assess agricultural greenhouse gases (GHG) potential reductions in countries with different farming productivity accounting for food security and economic performance of agricultural sector. The analysis focuses on non-radial slack that, theoretically, may be easily reduced by the improvement in available resource management. The DEA-based hybrid super-efficiency meta frontier model with undesirable output was employed, using the efficiency approach integrating three sustainability dimensions. The dataset consisted of data from 99 countries (2005-2018) divided into clusters. Several potential model orientations were tested and discussed with regard to agricultural policy objectives. It was found that by reducing slacks, agricultural emissions can be decreased by 0.74 Gt of CO2eq per year. Hence, removing only management inefficiencies would help achieve up to 80% of the global reduction targets in agriculture without a substantial technological change. However, the efficiency change component turned out to be mainly negative over the period studied; thus, a specific focus on agricultural policy is needed in terms of supporting farmers with a more rational use of their resources.

Multi‐Scale Modeling of a 3D Soft Magnetoelectric Patch for Wireless Nerve Stimulation

AbstractMagnetoelectric nanoparticles (MENPs) are able to locally generate high electric fields when activated with human‐safe, low‐intensity magnetic fields. However, when implanted as individual or randomly positioned small clusters, the induced electric fields decay very quickly with the distance, hampering effective tissue stimulation. Herein, a novel nano‐structured polymeric‐based MENPs‐loaded 3D system (ME‐Patch) is designed and optimized in terms of its electrical performances through a holistic and multi‐scale in silico framework, which spans from the multi‐physics modeling of the magnetoelectric phenomenon at the nanoscale to a functional assessment of the micrometric ME‐Patch stimulation ability in a realistic model of a human peripheral nerve. This study presents the theoretical applicability of a material‐based recipe for the fabrication of effective soft and biocompatible magnetoelectric devices, able to store and transfer the extremely localized effect of individual MENPs on tissue areas and trigger neuron action potential activation.

Prediction of mass and radii of anisotropic polytropic compact objects with Buchdahl-I metric

In this article, we discuss several compact objects (GW 190814, PSR J0952-0607, PSR J0030+0451, PSR J0740+6620, GW 170817, PSR J1614-2230, PSR J2215+5135, and 4U 1608-52) to predict their masses and radii. A generalized polytropic stellar model within the framework of general relativity is derived by employing the Buchdahl-I metric. All the physical quantities such as energy density, radial, and tangential pressure are well behaved, continuous and no singularity is observed. The obtained results are compatible with observational data for compact objects under consideration. The physical stability of this model is determined by using generalized hydrostatic equilibrium condition, energy conditions, causality conditions and Herrera’s cracking technique. We observe that our model fulfills all of the requirements for being a physically realistic model.

The Quest for a Stable Disk

Abstract The majority of disk galaxies manifest spirals and/or bars that are believed to result from dynamical instabilities. However, some galaxies have featureless disks, which are therefore inferred to be dynamically stable. Yet despite many years of effort, theorists have been unable to construct realistic models of galaxy disks that possess no instabilities and therefore could remain featureless. This conclusion has been reached through simulations for the most part, some of which have been confirmed by linear stability analyses. A. Toomre (1981) claimed that the Mestel disk, embedded in an equal-mass halo, is a notable counterexample, but his prediction of stability could not be reproduced in simulations, due to complicated nonlinear effects that caused secular growth of Poisson noise–driven disturbances until strong features emerged. Here, we revisit this issue and show that simply eliminating the most nearly circular orbits from Toomre's disk model can inhibit troublesome secular growth. We also present both 2D and 3D simulations of particle disks that remain featureless for over 50 orbit periods. We report that spiral evolution naturally depletes circular orbits and that the radial velocity distribution in the featureless disks of S0 galaxies should have negative kurtosis.

Protocells Either Synchronize or Starve

Two different processes take place in self-reproducing protocells, i.e., (i) cell reproduction by fission and (ii) duplication of the genetic material. One major problem is indeed that of assuring that the two processes take place at the same pace, i.e., that they synchronize, which is a necessary condition for sustainable growth. In previous theoretical works, using dynamical models, we had shown that such synchronization can spontaneously emerge, generation after generation, under a broad set of hypotheses about the architecture of the protocell, the nature of the self-replicating molecules, and the types of kinetic equations. However, an important class of cases (quadratic or higher-order self-replication) did not synchronize in the models we had used, but could actually lead to divergence of the concentration of replicators. We show here that this behavior is due to a simplification of the previous models, i.e., the “buffering” hypothesis, which assumes instantaneous equilibrium of the internal and external concentrations of those compounds which can cross the cell membrane. That divergence disappears if we make use of more realistic dynamical models, with finite transmembrane diffusion rates of the precursors of replicators.

Research on spatial resolution in cardiac source imaging for multiple measurement modes using a realistic multi-tissue human model

Research on spatial resolution in cardiac source imaging for multiple measurement modes using a realistic multi-tissue human model

Evaluation of (Shared) Autonomy in Robot-Assisted Vitreoretinal Surgery Using a Surgical Model.

Robot-assisted vitreoretinal surgery makes it easier for the surgeons to perform precise and dexterous manipulations required in vitreoretinal procedures. We systematically evaluated manual surgery, conventional two-hand teleoperation, a novel one-hand teleoperation, and automation in a needle positioning task using a realistic surgical eye model, measuring the expert surgeon's performances and the novice's learning curves. The proposed one-hand teleoperation improved the positioning accuracy of expert surgeons , enabled novices to achieve a consistent accuracy more quickly , decreased the novice's workload more quickly , and made it easier for novices to learn to conduct the task quickly . Moreover, our autonomous positioning achieved an equivalent accuracy to the surgeons. The benefits and potential of task autonomy were shown. Further work is needed to evaluate the proposed methods in a more complex task.

Core to Cosmic Edge: SIMBA-C’s New Take on Abundance Profiles in the Intragroup Medium at z=0

We employ the simba-c cosmological simulation to study the impact of its upgraded chemical enrichment model (Chem5) on the distribution of metals in the intragroup medium (IGrM). We investigate the projected X-ray emission-weighted abundance profiles of key elements over two decades in halo mass (1013≤M500/M⊙≤1015). Typically, simba-c generates lower-amplitude abundance profiles than simba with flatter cores, in better agreement with observations. For low-mass groups, both simulations over-enrich the IGrM with Si, S, Ca, and Fe compared to observations, a trend likely related to inadequate modeling of metal dispersal and mixing. We analyze the 3D mass-weighted abundance profiles, concluding that the lower simba-c IGrM abundances are primarily a consequence of fewer metals in the IGrM, driven by reduced metal yields in Chem5, and the removal of the instantaneous recycling of metals approximation employed by simba. Additionally, an increased IGrM mass in low-mass simba-c groups is likely triggered by changes to the AGN and stellar feedback models. Our study suggests that a more realistic chemical enrichment model broadly improves agreement with observations, but physically motivated sub-grid models for other key processes, like AGN and stellar feedback and turbulent diffusion, are required to realistically reproduce observed group environments.

Communication Security and Stability in NNCSs: Realistic DoS Attacks Model and ISTA-Supervised Adaptive Event-Triggered Controller Design

Communication Security and Stability in NNCSs: Realistic DoS Attacks Model and ISTA-Supervised Adaptive Event-Triggered Controller Design

Fast EEG/MEG BEM-based forward problem solution for high-resolution head models.

A fast BEM (boundary element method) based approach is developed to solve an EEG/MEG forward problem for a modern high-resolution head model. The method utilizes a charge-based BEM accelerated by the fast multipole method (BEM-FMM) with an adaptive mesh pre-refinement method (called b-refinement) close to the singular dipole source(s). No costly matrix-filling or direct solution steps typical for the standard BEM are required; the method generates on-skin voltages as well as MEG magnetic fields for high-resolution head models within 90 s after initial model assembly using a regular workstation. The forward method is validated by comparison against an analytical solution on a spherical shell model as well as comparison against a full h-refinement method on realistic 1M facet human head models, both of which yield agreement to within 5 % for the EEG skin potential and MEG magnetic fields. The method is further applied to an EEG source localization (inverse) problem for real human data, and a reasonable source dipole distribution is found.

A novel theoretical model framework for the 3D CdZnTe drift strip detector

Advances in data analysis and model prediction offer new potential for enhancing radiation measurement technologies, particularly in detector characterization and real-time signal analysis. A key challenge is creating realistic detector models that accurately describe the complex physical processes of photon-matter interaction, signal formation including material characteristics, and measurement to enhance design optimization and detector physics understanding. This research study introduces the development of an Advanced Theoretical Detector Model (ATDM) framework to evaluate the physical effects of charge diffusion, repulsion, and trapping, enabling the generation of realistic detector-specific signals through model prediction. Using physics simulations, the ATDM geometry, material properties, electric fields, and electrode weighting potentials are modeled for the DTU Space large-area (16 cm2) 3D CZT drift strip detectors. The simulations are based on the adjoint equations method, which when applied to the charge continuity equation allows deriving a description of underlying Charge Induction Efficiency (CIE) in the model. This allows for precise 3D mapping of induced charge at any time or interaction position. Additionally, Monte Carlo simulations generate recoiled photo-electron trajectories in CZT, which, combined with simulations of their propagation and secondary scattering processes yield a realistic charge cloud distribution. Model verification is achieved through experiments using narrow slit-beam illumination from a 137Cs source, measuring pulse shapes in the 40×40×5 mm3 detector modules with 69 readout channels. The ATDM framework, applicable to various detector types, successfully captures experimental data, offering insights into the pulse shape formation, timing, and intrinsic detector parameters that could guide future electrode configuration optimization and on the fly photon-by-photon measurements. The results also suggest a potential for electron tracking capability in 3D CZT drift strip electrodes, an exciting development that could significantly advance polarimetry and Compton imaging instruments for the future high-energy missions.

Conformal multi-channel MIMO antenna for implantable leadless transcatheter pacing systems

Conformal multi-channel MIMO antenna for implantable leadless transcatheter pacing systems

Sensitivity of pteropod calcification to multi stressor variability in coastal habitats.

Comprehensive understanding of environmental multiple stressors on calcification in marine calcifiers remains an important topic of study, especially under ocean global change associated with multiple stressors. We explore the impact of multiple stressor on pteropod calcification in the southern Salish Sea (Washington, U.S.), a coastal estuarine system that exhibits a high degree of spatial and temporal variability in multiple environmental parameters across sampling locations. We hypothesized that such variability is associated with differences in pteropod calcification. Shell thickness and shell density across pteropod life history stages was compared with high-resolution outputs from a realistic model of regional circulation and biogeochemistry to explore how the mean and variability of multiple stressors (aragonite saturation state (Ωar), temperature, food availability) influence calcification. We found that both the mean and variability in multiple stressors play a major role in calcification in pteropods, with a generalized linear model explaining more than 60% of the variance. We suggest two different modes of shell building: stable conditions of lower mean Ωar trigger the loss of shell thickness and density. In the more variable habitats, i.e., where the variability occurs over diel and seasonal scales, shell thickness increases at higher Ωar variability and greater food availability, which might partially compensate for the loss of shell density. This plastic response appears to be consistent across life stages and could represent a response mechanism that allows some compensatory calcification under less favourable conditions. However, compensation is very limited, as evident by lower shell growth resulting in shell sizes comparable to early life stages. These results substantially improve the understanding of the variability in multiple stressors on the calcification process under multiple stressors and provide a foundation for the development of two new proxies for calcification monitoring, and with implications for marine carbon dioxide removal strategies.

Simulating realistic self-interacting dark matter models including small and large-angle scattering

Dark matter (DM) self-interactions alter matter distribution on galactic scales and alleviate tensions with observations. A feature of the self-interaction cross section is its angular dependence, which influences offsets between galaxies and DM halos in merging galaxy clusters. While algorithms for modelling mostly forward-dominated or mostly large-angle scatterings exist, incorporating realistic angular dependencies within N-body simulations remains challenging. To efficiently simulate models with a realistic angle dependence, such as light mediator models, we developed, validated, and applied a novel method. We combined existing approaches to describe small- and large-angle scattering regimes within a hybrid scheme. Below a critical angle, the scheme uses the effective description of small-angle scattering via a drag force combined with transverse momentum diffusion, while above the angle, it samples the dependence explicitly. We first verified the scheme using a test set-up with known analytical solutions, and we checked that our results are insensitive to the choice of the critical angle within an expected range. Next, we demonstrated that our scheme speeds up the computations by multiple orders of magnitude for realistic light mediator models. Finally, we applied the method to galaxy cluster mergers. We discuss the sensitivity of the offset between galaxies and DM to the angle dependence of the cross section. Our scheme ensures accurate offsets for mediator mass m_ϕ and DM mass m_χ within the range $0.1v/c m_ϕ/m_χ v/c$, while for larger (smaller) mass ratios, the offsets obtained for isotropic (forward-dominated) self-scattering are approached. Here, v is the typical velocity scale. Equivalently, the upper condition can be expressed as $1.1 tot /σ_ T 10$ for the ratio of the total and momentum transfer cross sections, with the ratio being $1$ (∞) in the isotropic (forward-dominated) limits.

3D tlačené syntetické modely určené na tréning minimálne invazívnej detskej chirurgie – vlastné skúsenosti a prehľad literatúry

Pediatric surgery is a medical specialty focused on the diagnosis, treatment, and postoperative care of children with congenital and acquired anomalies and diseases. The goal of pediatric surgeons is to ensure that children receive the best possible care while minimizing the risks and complications associated with surgical procedures. Contemporary pediatric surgeons face many challenges, including a decline in the number of children with congenital developmental defects, economic pressures, and efforts to increase efficiency, leading to reduced time spent on individual surgeries. This can limit the opportunity for thorough training of young surgeons. These challenges require innovative approaches and continuous improvement in educational and training methods. Minimally invasive surgery has become a significant part of pediatric surgery, offering benefits such as faster recovery, smaller surgical wounds, and lower risk of infection. However, minimally invasive pediatric surgery is technically demanding and requires excellent technical skills. The need to maintain and improve surgical skills demands ongoing training. Current educational methods increasingly rely on simulation technologies to enhance the quality and safety of training without risk to patients. The integration of 3D printing technology and imaging data from CT and MRI scans has opened new possibilities for creating highly realistic simulation models for minimally invasive surgery. These models accurately replicate the environment encountered in procedures like neonatal surgery. In this article, we present our experience with the development and creation of 3D-printed synthetic models designed for training thoracoscopic surgery of esophageal atresia with tracheoesophageal fistula. The aim of this review article is to provide an up-to-date overview of the literature on synthetic 3D-printed models designed for training in minimally invasive pediatric surgery.