29 research outputs found
Ion exchange selectivity of phillipsite for Cs and Sr as a function of framework composition
Cs and Sr exchange reactions for Na on sedimentary, hydrothermal and synthetic phillipsites are studied by determining their exchange isotherms at 25 degrees C and 0.1 total normality, and computing the related thermodynamic quantities K-a, and Delta G degrees. Sedimentary and synthetic phillipsite, characterized by a higher Si/Al ratio, display good selectivity for Cs and moderate selectivity for Sr. The more aluminous hydrothermal phillipsite displays a lower selectivity for Cs and a higher selectivity for Sr than sedimentary and synthetic phillipsite do. These results, perfectly explainable in terms of field strength of the anionic zeolite framework and of ion charge density, demonstrate that the joint removal of Cs and Sr from water by phillipsite would be possible, provided cheap widespread aluminous phillipsite-rich materials were available
A 3D numerical model of controlled drug delivery to solid tumor by means of mild microwave hyperthermia-activated thermo-sensitive liposomes
A computational 3D analysis of liposomal drug delivery to investigate the effectiveness of this innovative therapy as an alternative to conventional chemotherapy is shown in this study. The temperature field evolution is obtained via the Local Thermal Non-Equilibrium (LTNE) bioheat model by including both variable porosity and blood vessels sizes to describe the local structure of the investigated tissue. Heating is induced by means of a microwave antenna directly inserted in tumor tissue, supplying a pulsating power to avoid tissue necrosis. Interstitial flow and drug diffusion are modeled by means of Darcy's law and convection-diffusion equations, respectively; Starling's law is included to simulate transcapillary exchange. After validating the model with available literature data, the results show that liposomal drug delivery leads to a 10% improvement in therapeutic outcomes (i.e., Fraction of Killed Cells, FKC). It is also proved that considering blood flow in the LTNE porous media model yields a more realistic evolution of drug diffusion and subsequent FKC, while severe tissue damage is avoided because of the pulsating power supply. This study highlights the potential benefits of using liposomal drug delivery in cancer chemotherapy via microwave-induced heating