98%
921
2 minutes
20
Simulations of the ventricular flow patterns during left ventricular assist device (LVAD) support are mainly performed with idealized cylindrical inflow, neglecting the influence of the atrial vortex. In this study, the influence of the left atrium (LA) on the intra-ventricular flow was investigated via Computational Fluid Dynamics (CFD) simulations. Ventricular flow was simulated by a combined Eulerian (carrier flow)/Lagrangian (particles) approach taking into account either the LA or a cylindrical inflow section to mimic a fully support condition. The flow deviation at the mitral valve, the blood low-velocity volume as well as the residence time and shear stress history of the particles were calculated. Inclusion of the LA deflects the flow at the mitral valve by 25°, resulting in an asymmetric flow jet entering the left ventricle. This reduced the ventricular low-velocity volume by 40% (from 6.4 to 3.9 cm), increased (40%) the shear stress experienced by particles and correspondingly increased (27%) their residence time. Under the studied conditions, the atrial geometry plays a major role in the development of intraventricular flow patterns. A reliable prediction of blood flow dynamics and consequently thrombosis risk analysis within the ventricle requires the consideration of the LA in computational simulations.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8922056 | PMC |
http://dx.doi.org/10.1177/03913988211056018 | DOI Listing |
Philos Trans A Math Phys Eng Sci
September 2025
Research Institute for Mathematical Sciences, Kyoto University, Kyoto, Japan.
Transport phenomena of microswimmers in fluid flows play a crucial role in various biological processes, including bioconvection and cell sorting. In this article, we investigate the dispersion behaviour of chiral microswimmers in a simple shear flow using the generalized Taylor dispersion theory, inspired by biased locomotion of bacterial rheotaxis swimmers. We thus focused on the influence of shear-induced torque effects due to particle chirality, employing an extended Jeffery equation for individual deterministic dynamics.
View Article and Find Full Text PDFPhilos Trans A Math Phys Eng Sci
September 2025
Department of Bioscience and Engineering, Shibaura Institute of Technology, Saitama, Japan.
The physical environment exerts a profound influence on microbial life. The directional movement of cells in response to their physical environment is understood as taxis, which has been studied in biology as chemotaxis, phototaxis, gravitaxis and so forth. These taxis are induced by physiological, physical or both factors.
View Article and Find Full Text PDFPhilos Trans A Math Phys Eng Sci
September 2025
Department of Mathematical Sciences, University of Liverpool, Liverpool, UK.
Microswimmer locomotion in non-Newtonian fluids is crucial for biological processes, including infection, fertilization and biofilm formation. The behaviour of microswimmers in these media is an area with many conflicting results, with swimmers displaying varying responses depending on their morphology, actuation and the complex properties of the surrounding fluid. Using a hybrid computational approach, we numerically investigate the effect of shear-thinning rheology and viscoelasticity on a simple conceptual microswimmer consisting of three linked spheres.
View Article and Find Full Text PDFPhilos Trans A Math Phys Eng Sci
September 2025
Department of Mathematics, University of York, York, UK.
The combined effect of axial stretching and cross-stream diffusion on the downstream transport of solute is termed Taylor dispersion. The dispersion of active suspensions is qualitatively distinct: viscous and external torques can establish non-uniform concentration fields with weighted access to shear, modifying mean drift and effective diffusivity. It would be advantageous to fine-tune the dispersion for systems such as bioreactors, where mixing or particle separation can improve efficacy.
View Article and Find Full Text PDFCNS Neurosci Ther
September 2025
Department of Neurosurgery, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.
Aims: Sustained neuroinflammation following ischemic stroke impedes post-injury tissue repairment and neurological functional recovery. Developing innovative therapeutic strategies that simultaneously suppress detrimental inflammatory cascades and facilitate neurorestorative processes is critical for improving long-term rehabilitation outcomes.
Methods: We employed a microglia depletion-repopulation paradigm by administering PLX5622 for 7 days post-ischemia; followed by a 7-day withdrawal period to allow microglia repopulation.