No abstract

Thus far, despite many investigations have been carried out for photo-triggered drug delivery systems, most of them suffer from an intrinsic drawback of without real-time monitoring mechanism. Incident intensity of light is a feasible parameter to monitor the drug release profiles. However, it is difficult to measure the incident laser power irradiated onto the photo-triggered carriers in drug delivery systems during in vivo therapy. We design an online measurement method based on the fluorescence intensity ratio (FIR) technique through upconversion nanoparticles. FIR value varies with temperature of sample due to the thermal effect induced by the incident laser, which validates the laser power measurement. Effects of rare earth doping concentration, as well as experimental conditions including laser spots and wavelengths on the measurement behavior were also investigated.

In this study, by introducing the finite element method (FEM) into the improved element-free Galerkin (IEFG) method, the dimension coupling method (DCM) is proposed for solving three-dimensional (3D) Helmholtz and Poisson’s equations efficiently. The dimensional splitting method is introduced into the corresponding governing equations, thus 3D equations can be split into a series of 2D ones. The IEFG method is selected to discretize those 2D forms, thus the discretized equations are derived easily by using the weak forms. In the third direction, the FEM is selected to couple those discretized equations, thus the final linear equation of 3D equation is derived. In numerical examples, the good convergence of the DCM for Helmholtz and Poisson’s equations is shown. The solutions of numerical examples show that the computational efficiency of the IEFG method is improved significantly without losing the computational accuracy when the DCM is used. In addition, the DCM can enhance the computational efficiency of the hybrid element-free Galerkin (HEFG) method significantly without too many layers when the natural boundary conditions exist in the splitting direction.