An unsteady analysis of two-phase binding of drug in an asymmetric stenosed vessel

In this paper, we investigate endovascular delivery to get a step ahead of the pharmacological limitations it has due to the complexity of dealing with a patient-specific vessel through a mathematical model. We divide the domain of computation into four sub-domains: the lumen, the lumen-tissue interface, the upper tissue and the lower tissue which are extracted from an asymmetric atherosclerotic image derived by the intravascular ultrasound (IVUS) technique. The injected drug at the luminal inlet is transported with the streaming blood which is considered Newtonian. An irreversible uptake kinetics of the injected drug at the lumen-tissue interface from the luminal side to the tissue domains is assumed. Subsequently, the drug is dispersed within the tissue followed by its retention in the extracellular matrix (ECM) and by receptor-mediated binding. The Marker and Cell (MAC) method has been leveraged to get a quantitative insight into the model considered. The effect of the wall absorption parameter on the concentration of all drug forms (free as well as two-phase bound) has been thoroughly investigated, and some other important factors, such as the averaged concentration, the tissue content, the fractional effect, the concentration variance and the effectiveness of drug have been graphically analyzed to gain a clear understanding of endovascular delivery. The simulated results predict that with increasing values of the absorption parameter, the averaged concentrations of all drug forms do decrease. An early saturation of binding sites takes place for smaller values of the absorption parameter, and also rapid saturation of ECM binding sites occurs as compared to receptor binding sites. Results also predict the influence of surface roughness as well as asymmetry of the domain about the centerline on the distribution and retention of drug. A thorough sensitivity analysis has been carried out to determine the influence of some parameters involved.

Unsteady reactive magnetic radiative micropolar flow, heat and mass transfer from an inclined plate with Joule heating: A model for magnetic polymer processing

Magnetic polymer materials processing involves many multi-physical and chemical effects. Motivated by such applications, in the present work, a theoretical analysis is conducted of combined heat and mass transfer in unsteady mixed convection flow of micropolar fluid over an oscillatory inclined porous plate in a homogenous porous medium with heat source, radiation absorption and Joule dissipation. A first-order homogenous chemical reaction model is used. The transformed non-dimensional boundary value problem is solved using a perturbation method and Runge–Kutta fourth-order numerical quadrature (shooting technique). The emerging parameters dictating the transport phenomena are shown to be the gyro-viscosity micropolar material parameter, magnetic field parameter, permeability of the porous medium, Prandtl number, Schmidt number, thermal Grashof number, species Grashof number, thermal radiation–conduction parameter, heat absorption parameter, radiation absorption parameter, Eckert number, chemical reaction parameter and Eringen coupling number (vortex viscosity ratio parameter). The impact of these parameters on linear velocity, micro-rotation (angular velocity), temperature and concentration are evaluated in detail. Results for skin friction coefficient, couple stress coefficient, Nusselt number and Sherwood number are also included. Couple stress is observed to be reduced with stronger magnetic field. Verification of solutions is achieved with earlier published analytical results.

Effects of Heat Generation or Absorption on Free Convection Flow of a Nanofluid Past an Isothermal Inclined Plate

In this paper, the effects of internal heat generation or absorption on free convection flow of a nanofluid past an isothermal inclined plate have been investigated numerically. The governing boundary-layer equations are first transformed into a system of coupled nonlinear ordinary differential equations using similarity variables. An efficient implicit finite-difference scheme known as the Keller-box method is employed to solve the resulting nonlinear equations. The effects of internal heat generation or absorption parameter on the flow fields have been presented graphically and discussed. It is found that the rate of heat transfer decreases with increasing heat generation, Brownian motion and thermophoresis parameters whereas it increases with increasing heat absorption parameter and Prandtl number.

On the existence of scrambling in the grammar of Japanese elementary EFL learners

This paper examines the representation of English WH-phrase movement in the grammars of Japanese elementary and intermediate EFL learners. It argues that elementary level speakers allow movement of the kind *How manyi did Bill think ti students are smart? and that this is because they treat WH-movement as scrambling. By contrast, intermediate EFL learners do not allow such movement. Given that scrambling is optional, the elementary subjects should also allow WH-phrases in situ. However, this is not the case for some of the speakers. It is suggested that in these cases, informants have an obligatory stylistic WH-fronting rule. It was also found that while the intermediate proficiency EFL learners have acquired the movement property of English WH-phrases, they have not acquired their quantificational force. It is argued that this follows if the Fquant Absorption parameter proposed by Watanabe (2000) has not been reset from its Japanese value.