Navegando por Autor "Orlande, Helcio R. B."
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Artigo Computational fluid dynamic analysis of physical forces playing a role in brain organoid cultures in two different multiplex platforms(2019-03-07) Goto-Silva, Livia; Ayad, Nadia M. E.; Herzog, Iasmin L.; Silva, Nilton P.; Lamien, Bernard; Orlande, Helcio R. B.; Souza, Annie da Costa; Ribeiro, Sidarta Tollendal Gomes; Martins, Michele; Domont, Gilberto B.; Junqueira, Magno; Tovar-Moll, Fernanda; Rehen, Stevens K.BACKGROUND: Organoid cultivation in suspension culture requires agitation at low shear stress to allow for nutrient diffusion, which preserves tissue structure. Multiplex systems for organoid cultivation have been proposed, but whether they meet similar shear stress parameters as the regularly used spinner flask and its correlation with the successful generation of brain organoids has not been determined. RESULTS: Here we used computational fluid dynamics (CFD) to simulate two multiplex culture conditions: steering plates on an orbital shaker and the use of a previously described bioreactor. The bioreactor had low speed and high shear stress regions that may affect cell aggregate growth, depending on volume, whereas the computed variables of the steering plates were closer to those of the spinning flask. CONCLUSION: Our protocol improves the initial steps of the standard brain organoid formation, and the produced organoids displayed regionalized brain structures, including retinal pigmented cells. Overall, we conclude that suspension culture on orbital steering plates is a cost-effective practical alternative to previously described platforms for the cultivation of brain organoids for research and multiplex testing.Artigo Numerical simulation of nanoparticles assisted laser photothermal therapy: a comparison of the P1‐approximation and discrete ordinate methods(Springer, 2016-05-05) Maurente, André Jesus Soares; Bruno, Alexandre Barbosa; Lamien, Bernard; Orlande, Helcio R. B.Photothermal therapy (PTT) with combined use of laser radiation and photon absorber nanoparticles is a promising technique to treat cancer. Treatment planning and devising appropriate protocols for cancer photo thermal therapy require the computational simulation of coupled physical phenomena, such as radiation, conduction, and blood perfusion. The P1-approximation is a numerical method to solve radiation heat transfer which features the advantage of being computationally fast and, therefore, desirable for PTT simulations. However, the method is known to become inaccurate under certain conditions. In this study, the P1-approximation and the accurate discrete ordinate method were applied to solve a set of test problems idealized to portray conditions encountered in PTT. The test problems were one-dimensional, and the radiation scattering was assumed as isotropic. Tissues composed by layers with different properties were considered, including cases in which gold nanoparticles were embedded in the tissue to increase photon absorption. For the problems considered here, the P1-approximation and discrete ordinate method results presented quite good agreement for the time-dependent temperature distribution, which is the quantity of interest in PTT