Browsing by Author "da Silva, Nilton Pereira"
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Item Monte Carlo parameter estimation and direct simulation of in vitro hyperthermia-chemotherapy experiment(2021) da Silva, Nilton Pereira; Varon, Leonardo Antonio Bermeo; da Costa, José Mir Justino; Orlande, Helcio Rangel BarretoThe objective of this work was to estimate parameters of a model for diode-laser heating of a culture of cancer cells under the effects of a chemotherapy drug. Two mathematical models were proposed to represent the physical problem during heating: natural convection was considered in the high-fidelity model, while the low-fidelity model was given by a lumped system. The thermal damage caused in the cells by the heating was modeled as a first-order reaction. A Bayesian approach was applied to estimate model parameters with the Markov Chain Monte Carlo (MCMC) method, which was implemented with the Metropolis-Hastings algorithm. The Approximation Error Model (AEM) approach was used to speed up calculations for the inverse problem solution when the high-fidelity model was replaced by the low-fidelity model for the computation of dependent variables. Monte Carlo direct simulations were also performed to compute the transient variation of the number of cells during periods before and after the imposed heating.Item Thermal Effect by Applying Laser Heating in Iron Oxide Nanoparticles Dissolved in Distilled Water(Springer, 2019-09-25) Bermeo Varon, Leonardo A.; Loiola, Bruna R.; da Silva Abreu, Luiz A.; Lamien, Bernard; da Silva, Nilton Pereira; da Silva, Nilton Pereira; Silva dos Santos, DilsonDue to their physical properties and biocompatibility, iron oxide nanoparticles have received particular attention in recent years for the localized hyperthermia therapy, where they are targeted to an organ, tissue or tumor and an external source is used for heating. Several physical, chemical and biological methods have been used to synthetize nanoparticles. A mechanical alloying method was used in this work to manufacture Fe2O3 nanoparticles. The size and shape of the nanoparticles were measured by scanning electron microscopy and X-ray diffraction. In this work, experiments were conducted with the nanoparticles dissolved in distilled water and heated by a laser in the near infrared range, with temperature measurements taken by an infrared camera. Numerical simulations were performed with COMSOL Multiphysics and compared to the experimental results. The numerical results agree with the measurements within the experimental uncertainties. The experimental results revealed a larger temperature increase of the sample surface for a larger concentration of nanoparticles. Hence, the Fe2O3 nanoparticles manufactured in this work behaved as a thermal agent with potential use for the hyperthermia therapy, including the treatment of cancer.