Wyniki wyszukiwania - BazTech

1

Computer-based simulation of plasma concentration time-proﬁles of drug in nonlinear two-compartment model

Piekarski S., Kiełczyński P., Szalewski M., Rewekant M.

Computer Assisted Methods in Engineering and Science

|

2013

|

Vol. 20, no. 4

279--288

EN

The main interest of pharmacokinetics is the study of the fate of drugs in the living organism. This work proposes the system of the conservation laws that describes time-dependent concentrations of a drug, after a single intravenous administration. Compared with others, the proposed model considers both free and protein-bound drug concentrations at the same time. Plasma protein binding captured in the model enters the nonlinearity arising from the Guldberg-Waage law. According to our best knowledge, the analytical solution for our system does not exist. Our model allows the calculation of the free and bound-drug protein concentrations at any time point and at any dose after single intravenous bolus dose administration. In order to compare the empirical with simulated data, a numerical approach has been proposed. On the basis of published experimental data the model validation has been carried out. The goodness of ﬁt was satisfactory (R 2 = 0.99) and the experimental and simulated AUC (area under the curve) values, as the measure of the bioavailability of drug, were similar (150 M/hxh−1). The preliminary assessment of the model credibility was positive and encouraged further studies.

2

On resonant interaction of capillary-gravity wave and internal wave

Debsarma S., Das K. P.

International Journal of Applied Mechanics and Engineering

|

2008

|

Vol. 13, no 3

653-668

EN

The fourth order nonlinear evolution equations are derived for a capillary-gravity wave packet for the case of resonant interaction with internal wave in the presence of a thin thermocline at a finite depth in deep water. These equations are used to make stability analysis of a uniform capillary-gravity wave train when resonance condition is satisfied. It is observed that for surface gravity waves the instability region expands with the decrease of thermocline depth. For surface capillary-gravity waves the growth rate of instability is much higher if the thermocline is formed at lower depth and for a fixed thermocline depth it increases with the increase of wave amplitude.

3

The Asymptotical Stability of a Dynamic System With Structural Damping

Hou X.

International Journal of Applied Mathematics and Computer Science

|

2003

|

Vol. 13, no 2

131-138

EN

A dynamic system with structural damping described by partial differential equations is investigated. The system is first converted to an abstract evolution equation in an appropriate Hilbert space, and the spectral and semigroup properties of the system operator are discussed. Finally, the well-posedness and the asymptotical stability of the system are obtained by means of a semigroup of linear operators.

4

The existence of moments of solutions to transport equations with inelastic scattering and thie applications in the asymptotic analysis

Banasiak J.

Journal of Applied Analysis

|

2000

|

Vol. 6, nr 2

187-211

EN

In this paper we prove the existence of all moments of the solutions to the time-dependent spatially homogeneous transport equation describing elastic and inelastic scattering of particles. The proof uses the theory of resolvent positive operators and Desch's perturbation theorem. As an application we carry out the asymptotic analysis of the full transport equation with dominant elastic scattering and, using the results of the first part of the paper, we show that its solution can be approximated in the L1-norm by the solution of the limit equation obtained by formal asymptotic expansion.