Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 5 de 5
Filtrar
Más filtros













Base de datos
Intervalo de año de publicación
1.
Microvasc Res ; 142: 104375, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35577615

RESUMEN

The present study considers the mathematical modelling of unsteady non-Newtonian hydro-magnetic nano-hemodynamics through a rigid cylindrical artery featuring two different stenoses (composite and irregular). The Ostwald-De Waele power-law fluid model is adopted to simulate the non-Newtonian characteristics of blood. Inspired by drug delivery applications for cardiovascular treatments, blood is considered doped with a homogenous suspension of biocompatible nanoparticles. The arterial vessel exhibits the permeability effect (lateral influx/efflux), and an external magnetic field is also applied in the radial direction to the flow. A combination of the Buongiorno and Tiwari-Das nanoscale models is adopted. The strongly nonlinear nature of the governing equations requires a robust numerical method, and therefore the finite difference technique is deployed to solve the resulting equations. Validation of solutions for the pure blood case (absence of nanoparticles) is included. Comprehensive solutions are presented for shear-thickening (n = 1.5) and shear-thinning (n = 0.5) blood flow for the effects of crucial nanoscale thermophysical, solutal parameters, and hydrodynamic parameters. Comparison of profiles (velocity, temperature, wall shear stress, and flow rate) is also made for composite and irregular stenosis. Colour visualization of streamline plots is included for pure blood and nano mediated blood both with and without applied magnetic field. The inclusion of nanoparticles (Cu/blood) within blood increases the axial velocity of blood. By applying external magnetic field in the radial direction, axial velocity is significantly damped whereas much less dramatic alterations are computed in blood temperature and concentration profiles. The simulations are relevant to the diffusion of nano-drugs in magnetic targeted treatment of stenosed arterial diseases.

2.
Microvasc Res ; 139: 104241, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34508788

RESUMEN

The present study considers the mathematical modeling of unsteady non-Newtonian hydro-magnetic nano-hemodynamics through a rigid cylindrical artery featuring two different stenoses (composite and irregular). The Ostwald-De Waele power-law fluid model is adopted to simulate the non-Newtonian characteristics of blood. Inspired by drug delivery applications for cardiovascular treatments, blood is considered doped with a homogenous suspension of biocompatible nanoparticles. The arterial vessel exhibits the permeability effect (lateral influx/efflux), and an external magnetic field is also applied in the radial direction to the flow. A combination of the Buongiorno and Tiwari-Das nanoscale models is adopted. The strongly nonlinear nature of the governing equations requires a robust numerical method, and therefore the finite difference technique is deployed to solve the resulting equations. Validation of solutions for the pure blood case (absence of nanoparticles) is included. Comprehensive solutions are presented for shear-thickening (n = 1.5) and shear-thinning (n = 0.5) blood flow for the effects of crucial nanoscale thermophysical, solutal parameters, and hydrodynamic parameters. Comparison of profiles (velocity, temperature, wall shear stress, and flow rate) is also made for composite and irregular stenosis. Colour visualization of streamline plots is included for pure blood and nano mediated blood both with and without applied magnetic field. The inclusion of nanoparticles (Cu/blood) within blood increases the axial velocity of blood. By applying external magnetic field in the radial direction, axial velocity is significantly damped whereas much less dramatic alterations are computed in blood temperature and concentration profiles. The simulations are relevant to the diffusion of nano-drugs in magnetic targeted treatment of stenosed arterial diseases.


Asunto(s)
Arterias/fisiopatología , Portadores de Fármacos , Hemodinámica , Modelos Cardiovasculares , Nanopartículas , Análisis Numérico Asistido por Computador , Preparaciones Farmacéuticas/sangre , Enfermedades Vasculares/tratamiento farmacológico , Arterias/patología , Simulación por Computador , Constricción Patológica , Composición de Medicamentos , Análisis de Elementos Finitos , Humanos , Permeabilidad , Preparaciones Farmacéuticas/administración & dosificación , Preparaciones Farmacéuticas/química , Enfermedades Vasculares/patología , Enfermedades Vasculares/fisiopatología
3.
Comput Biol Med ; 139: 105009, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34775156

RESUMEN

Influenced by nano-drug delivery applications, the present article considers the collective effects of hybrid biocompatible metallic nanoparticles (Silver and Copper), a stenosis and an aneurysm on the unsteady blood flow characteristics in a catheterized tapered inclined artery. The non-Newtonian Carreau fluid model is deployed to represent the hemorheological characteristics in the arterial region. A modified Tiwari-Das volume fraction model is adopted for nanoscale effects. The permeability of the arterial wall and the inclination of the diseased artery are taken into account. The nanoparticles are also considered to have various shapes (bricks, cylinders, platelets, blades) and therefore the influence of different shape parameters is discussed. The conservation equations for mass, linear momentum and energy are normalized by employing suitable non-dimensional variables. The transformed equations with associated boundary conditions are solved numerically using the FTCS method. Key hemodynamic characteristics i.e. velocity, temperature, flow rate, wall shear stress (WSS) in stenotic and aneurysm region for a particular critical height of the stenosis, are computed. Hybrid nanoparticles (Ag-Cu/Blood) accelerate the axial flow and increase temperatures significantly compared with unitary nanoparticles (Ag/blood), at both the stenosis and aneurysm segments. Axial velocity, temperature and flow rate are all enhanced with greater nanoparticle shape factor. Axial velocity, temperature, wall shear stress and flow rate magnitudes are always comparatively higher at the aneurysm region compared with the stenotic segment. The simulations provide novel insights into the performance of different nanoparticle geometries and also rheological behaviour in realistic nano-pharmaco-dynamic transport and percutaneous coronary intervention (PCI).


Asunto(s)
Nanopartículas del Metal , Intervención Coronaria Percutánea , Arterias , Velocidad del Flujo Sanguíneo , Simulación por Computador , Constricción Patológica , Hemodinámica , Humanos , Modelos Cardiovasculares , Estrés Mecánico
4.
Proc Inst Mech Eng H ; 235(10): 1175-1196, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34154464

RESUMEN

Two-dimensional laminar hemodynamics through a diseased artery featuring an overlapped stenosis was simulated theoretically and computationally. This study presented a mathematical model for the unsteady blood flow with hybrid biocompatible nanoparticles (Silver and Gold) inspired by drug delivery applications. A modified Tiwari-Das volume fraction model was adopted for nanoscale effects. Motivated by the magneto-hemodynamics effects, a uniform magnetic field was applied in the radial direction to the blood flow. For realistic blood behavior, Reynolds' viscosity model was applied in the formulation to represent the temperature dependency of blood. Fourier's heat conduction law was assumed and heat generation effects were included. Therefore, the governing equations were an extension of the Navier-Stokes equations with magneto-hydrodynamic body force included. The two-dimensional governing equations were transformed and normalized with appropriate variables, and the mild stenotic approximation was implemented. The strongly nonlinear nature of the resulting dimensionless boundary value problem required a robust numerical method, and therefore the FTCS algorithm was deployed. Validation of solutions for the particular case of constant viscosity and non-magnetic blood flow was included. Using clinically realistic hemodynamic data, comprehensive solutions were presented for silver, and silver-gold hybrid mediated blood flow. A comparison between silver and hybrid nanofluid was also included, emphasizing the use of hybrid nanoparticles for minimizing the hemodynamics. Enhancement in magnetic parameter decelerated the axial blood flow in stenotic region. Colored streamline plots for blood, silver nano-doped blood, and hybrid nano-doped blood were also presented. The simulations were relevant to the diffusion of nano-drugs in magnetic targeted treatment of stenosed arterial diseases.


Asunto(s)
Nanopartículas , Preparaciones Farmacéuticas , Arterias , Hemodinámica , Calor , Modelos Cardiovasculares
5.
Comput Biol Med ; 130: 104213, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33535145

RESUMEN

This article examines theoretically and numerically the unsteady two-dimensional blood flow through a diseased artery featuring an irregular stenosis. An appropriate geometric model is adopted to simulate the irregular stenotic artery. Inspired by drug delivery applications for blood vessels, the impact of hybrid nanoparticles on blood flow using a modified Tiwari-Das model is discussed. The blood is examined to have a homogenous suspension of hybrid nanoparticles. Reynolds' viscosity model is applied in the formulation to represent the temperature dependency of blood. The two-dimensional governing conservation equations for momentum and heat transfer with buoyancy effect are simplified by considering the mild stenotic approximation. A finite-difference technique is deployed to numerically discretize the transformed non-dimensional model. Extensive graphical results for blood flow characteristics are obtained by MATLAB code. Comprehensive visualization of the effects of hemodynamic, geometric and nanoscale parameters on transport characteristics is provided. The problem is conducted for silver and silver-gold hybrid mediated blood flow models, and experimental values of blood and these biocompatible metallic nanoparticles. A comparison between silver and hybrid nanofluid is obtained which promotes the use of hybrid nanoparticles in successfully achieving clinically more beneficial results associated with nano-drug delivery in diseased hemodynamics. Enhancement in viscosity parameter induces axial flow acceleration in the stenotic region while lower thermal conductivity decreases the temperature magnitudes. Furthermore, with time variation, the pressure gradient is found to be lower in coronary arteries comparatively to femoral arteries. The simulations are relevant to transport phenomenon in nano-drug targeted delivery in haematology.


Asunto(s)
Modelos Cardiovasculares , Plata , Simulación por Computador , Constricción Patológica , Hemodinámica , Humanos
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA