Long-term disease burden and survivorship issues after surgery and radiotherapy of intracranial meningioma patients

BACKGROUND Many intracranial meningioma patients have an impaired health-related quality of life (HRQoL) and neurocognitive functioning up to 4 yr after intervention. OBJECTIVE To assess the long-term (≥5 yr) disease burden of meningioma patients. METHODS In this multicenter cross-sectional study, patients ≥5 yr after intervention (including active magnetic resonance imaging (MRI) surveillance) were included and assessed for HRQoL (Short-Form Health Survey 36), neurocognitive functioning (neuropsychological assessment), anxiety and depression (Hospital Anxiety and Depression Scale), and work productivity (Short Form-Health and Labour Questionnaire). Multivariable and propensity score regression analyses were used to compare patients and controls, and different treatment strategies corrected for possible confounders. Clinically relevant differences were reported. RESULTS At a median of 9 yr follow-up after intervention, meningioma patients (n = 190) reported more limitations due to physical (difference 12.5 points, P = .008) and emotional (13.3 points, P = .002) health problems compared with controls. Patients also had an increased risk to suffer from anxiety (odds ratio [OR]: 2.6, 95% CI: 1.2-5.7) and depression (OR: 3.7, 95% CI: 1.3-10.5). Neurocognitive deficits were found in 43% of patients. Although postoperative complications, radiotherapy, and reresection were associated with worse verbal memory, attention, and executive functioning when compared to patients resected once, the only clinically relevant association was between reresection and worse attention (–2.11, 95% CI: –3.52 to –0.07). Patients of working age less often had a paid job (48%) compared with the working-age Dutch population (72%) and reported more obstacles at work compared with controls. CONCLUSION In the long term, a large proportion of meningioma patients have impaired HRQoL, neurocognitive deficits, and high levels of anxiety or depression. Patients treated with 1 resection have the best neurocognitive functioning

An immersed boundary method for simulation of flow with heat transfer

In this work, the hybrid immersed boundary method is extended with immersed boundary conditions for the temperature field. The method is used to couple the flow solver with a shell heat transfer solver. The coupling back to the shell is handled by a heat source, calculated from Fourier's law. Natural convection in a square cavity with and without a hot circular cylinder, and free air cooling of an electrically heated plate are studied. For all cases an excellent agreement with numerical and experimental data is obtained. The proposed method is very well suited for many industrial applications involving natural convection

A virtual framework for simulation of complex viscoelastic flows

A framework is presented and demonstrated in which extrusion and laydown of viscoelastic fluids can be simulated. Examples include application of seam sealing and adhesive material, and additive manufacturing processes. A state of the art fluid flow solver is used to solve the flow equations and various rheological constitutive models are supported, such as shear thinning viscosity models or more complex viscoelastic stress models. With connection to robot path planning software the framework can be used in the product preparation phase to improve quality, reduce material consumption and commissioning time

Optimisation of robotised sealing stations in paint shops by process simulation and automatic path planning

Application of sealing materials is done in order to prevent water leakage into cavities of the car body, and to reduce noise. The complexity of the sealing spray process is characterised by multi-phase and free surface flows, multi-scale phenomena, and large moving geometries, which poses great challenges for mathematical modelling and simulation. The aim of this paper is to present a novel framework that includes detailed process simulation and automatic generation of collision free robot paths. To verify the simulations, the resulting width, thickness and shape of applied material on test plates as a function of time and spraying distance have been compared to experiments. The agreement is in general very good. The efficient implementation makes it possible to simulate application of one meter of sealing material in less than an hour on a standard computer, and it is therefore feasible to include such detailed simulations in the production preparation process and off -line programming of the sealing robots

Improved spray paint thickness calculation from simulated droplets using density estimation

Advancements in the simulation of electrostatic spray painting make it possible to evaluate the quality and efficiency of programs for industrial paint robots during Off-Line Programming (OLP). Simulation of the spray paint deposition process is very complex and requires physical simulation of the airflow, electric fields, breakup of paint into droplets, and tracking of these droplets until they evaporate or impact on a surface. The information from the simulated droplet impacts is then used to estimate the paint film thickness. The current common way of measuring paint thickness on complex geometrical shapes is to use histogram based methods. These methods are easy to implement but are dependent on good quality meshes. In this paper, we show that using kernel density estimation not only gives better estimates but it also is not dependent on mesh quality. We also extend the method using a multivariate bandwidth adapted using estimated gradients of the thickness. To show the advantages of the proposed method, all three methods are compared on a test case and with real thickness measurements from an industrial case study using a complex automotive part. Copyrigh

Robust intersection of structured hexahedral meshes and degenerate triangle meshes with volume fraction applications

Two methods for calculating the volume and surface area of the intersection between a triangle mesh and a rectangular hexahedron are presented. The main result is an exact method that calculates the polyhedron of intersection and thereafter the volume and surface area of the fraction of the hexahedral cell inside the mesh. The second method is approximate, and estimates the intersection by a least squares plane. While most previous publications focus on non-degenerate triangle meshes, we here extend the methods to handle geometric degeneracies. In particular, we focus on large-scale triangle overlaps, or double surfaces. It is a geometric degeneracy that can be hard to solve with existing mesh repair algorithms. There could also be situations in which it is desirable to keep the original triangle mesh unmodified. Alternative methods that solve the problem without altering the mesh are therefore presented. This is a step towards a method that calculates the solid area and volume fractions of a degenerate triangle mesh including overlapping triangles, overlapping meshes, hanging nodes, and gaps. Such triangle meshes are common in industrial applications. The methods are validated against three industrial test cases. The validation shows that the exact method handles all addressed geometric degeneracies, including double surfaces, small self-intersections, and split hexahedra

Particle swarm optimization applied to EEG source localization of somatosensory evoked potentials

One of the most important steps in presurgical diagnosis of medically intractable epilepsy is to find the precise location of the epileptogenic foci. Electroencephalography (EEG) is a noninvasive tool commonly used at epilepsy surgery centers for presurgical diagnosis. In this paper, a modified particle swarm optimization (MPSO) method is used to solve the EEG source localization problem. The method is applied to noninvasive EEG recording of somatosensory evoked potentials (SEPs) for a healthy subject. A 1 mm hexahedra finite element volume conductor model of the subject's head was generated using T1-weighted magnetic resonance imaging data. Special consideration was made to accurately model the skull and cerebrospinal fluid. An exhaustive search pattern and the MPSO method were then applied to the peak of the averaged SEP data and both identified the same region of the somatosensory cortex as the location of the SEP source. A clinical expert independently identified the expected source location, further corroborating the source analysis methods. The MPSO converged to the global minima with significantly lower computational complexity compared to the exhaustive search method that required almost 3700 times more evaluations

A multiscale methodology for simulation of mechanical properties of paper

In this work a multiscale framework developed for simulation of mechanical properties of paper is presented. The framework consists of two major parts. In the first part the forming process of a paper machine is simulated using the fiber suspension model developed in [8]. Fluid dynamics together with an advanced contact calculation method enables detailed simulation of the lay down process. The resulting paper sheet is used as input to the second part of the framework. In the second part the fiber configuration attained from the unique forming simulations is transformed into a network representation, enabling simulation of mechanical properties. The paper mechanics is governed by a fiber network model. To study macroscale properties a novel numerical upscaling method for networks has been developed. In this paper the complete simulation methodology is outlined and discussed

On the fully automatic construction of a realistic head model for EEG source localization

Accurate multi-tissue segmentation of magnetic resonance (MR) images is an essential first step in the construction of a realistic finite element head conductivity model (FEHCM) for electroencephalography (EEG) source localization. All of the segmentation approaches proposed to date for this purpose require manual intervention or correction and are thus laborious, time-consuming, and subjective. In this paper we propose and evaluate a fully automatic method based on a hierarchical segmentation approach (HSA) incorporating Bayesian-based adaptive mean-shift segmentation (BAMS). An evaluation of HSA-BAMS, as well as two reference methods, in terms of both segmentation accuracy and the source localization accuracy of the resulting FEHCM is also presented. The evaluation was performed using (i) synthetic 2D multi-modal MRI head data and synthetic EEG (generated for a prescribed source), and (ii) real 3D T1-weighted MRI head data and real EEG data (with expert determined sou rce localization). Expert manual segmentation served as segmentation ground truth. The results show that HSA-BAMS outperforms the two reference methods and that it can be used as a surrogate for manual segmentation for the construction of a realistic FEHCM for EEG source localization

Simulation of electrostatic rotary bell spray painting in automotive paint shops

A new framework for simulation of electrostatic spray painting is proposed based on novel algorithms for coupled simulations of air flow, electromagnetic fields, and paint droplets. Particularly important for the computational efficiency is the Navier-Stokes solver. The incompressible solver is based on a finite volume discretization on a dynamic Cartesian octree grid and unique immersed boundary methods are used to model the presence of objects in the fluid. This enables modeling of moving objects at virtually no additional computational cost and greatly simplifies preprocessing by avoiding the cumbersome generation of a body-conforming mesh. To validate the simulation framework an extensive measurement campaign has been performed. Several test plates and car fenders were painted with different process conditions and robot paths. The same cases were then simulated and overall the agreement between simulations and experiments are remarkably good. The very efficient impl ementation gives a major improvement of computational speed compared to other approaches and makes it possible to simulate spray painting of a full car in just a few hours on a standard computer