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A flexible mathematical model of an asymmetric bronchial airway bifurcation is presented. The bifurcation structure is automatically determined after the user specifies geometric parameters: radius of parent airway, radii of daughter airways, radii of curvature of the daughter branch toroids, bifurcation angles, and radius of curvature of carina ridge. Detailed shape in the region where the three airways merge is defined by several explicit functions and can be changed with ease in accordance with observed lung structure. These functions take into account the blunt shape of the carina, the smooth transition from the outer transition zone to the inner one, and the shift in carinal ridge starting position as a function of bifurcation asymmetry. We validated the bifurcation model by comparing it to a computed tomography image of a rat lung cast. Three-dimensional representations of the bifurcation geometry can be viewed at http://mae.ucdavis.edu/wexler/lungs/bifurc.htm.
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http://dx.doi.org/10.1002/ar.20643 | DOI Listing |
PLoS One
September 2025
Department of Mathematics and Statistics, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, Saudi Arabia.
This research explores the dynamical properties and solutions of actin filaments, which serve as electrical conduits for ion transport along their lengths. Utilizing the Lie symmetry approach, we identify symmetry reductions that simplify the governing equation by lowering its dimensionality. This process leads to the formulation of a second-order differential equation, which, upon applying a Galilean transformation, is further converted into a system of first-order differential equations.
View Article and Find Full Text PDFChaos
September 2025
Department of Mathematics, Visva-Bharati, Santiniketan 731235, India.
Biological models are important in describing species interaction, disease spread, and environmental processes. One key aspect in improving the predictive capability of these models is deciding which parametrization is used to formulate the mathematical model. Considering two distinct functions with similar shapes and the same qualitative properties in a model can lead to markedly different model predictions.
View Article and Find Full Text PDFChaos
September 2025
School of Engineering, University of Applied Sciences of Western Switzerland HES-SO, CH-1950 Sion, Switzerland.
We investigate species-rich mathematical models of ecosystems. While much of the existing literature focuses on the properties of equilibrium fixed-points, persistent dynamics (e.g.
View Article and Find Full Text PDFComput Methods Programs Biomed
September 2025
School of Biological Sciences and Medical Engineering, Southeast University, Nanjing, Jiangsu, China. Electronic address:
Background And Objective: The quantitative knowledge of the influence of the small airway disease on the functional changes in chronic obstructive pulmonary disease (COPD) patients has been severely limited.
Methods: This study presents an innovative patient-specific computational framework that integrates CT and OCT imaging data with multiscale computational fluid dynamics (CFD) analysis. A three-dimensional tracheobronchial tree is reconstructed from CT scans of a mild COPD patient, spanning from the central airway to the 4th generation bronchial bifurcations.
Comput Methods Programs Biomed
August 2025
School of Computer Science and Technology, Southwest University of Science and Technology, Mianyang 621010, China. Electronic address:
Background: Carotid web (CaW) is a rare fibromuscular dysplasia lesion at the carotid bifurcation linked to thromboembolic events in young patients. CaW-induced hemodynamic disturbances contribute to thrombosis, but the impact of CaW morphology on long-term thrombotic risk remains unclear.
Method: This study developed three-dimensional numerical models based on patient-specific carotid artery anatomy with CaW angles of 30°, 60°, and 90° (models A, B, and C).