Jorge Vicente Lopes da Silva | Universidade de São Paulo (original) (raw)

Papers by Jorge Vicente Lopes da Silva

Polymers, 2022

In this article, a recent formulation for real-time simulation is developed combining the strain ... more In this article, a recent formulation for real-time simulation is developed combining the strain energy density of the Spring Mass Model (SMM) with the equivalent representation of the Strain Energy Density Function (SEDF). The resulting Equivalent Energy Spring Model (EESM) is expected to provide information in real-time about the mechanical response of soft tissue when subjected to uniaxial deformations. The proposed model represents a variation of the SMM and can be used to predict the mechanical behavior of biological tissues not only during loading but also during unloading deformation states. To assess the accuracy achieved by the EESM, experimental data was collected from liver porcine samples via uniaxial loading and unloading tensile tests. Validation of the model through numerical predictions achieved a refresh rate of 31 fps (31.49 ms of computation time for each frame), achieving a coefficient of determination R2 from 93.23% to 99.94% when compared to experimental data. ...

Research, Society and Development, 2022

The objective of the research was to evaluate the distribution of stress produced by surgically a... more The objective of the research was to evaluate the distribution of stress produced by surgically assisted rapid maxillary expansion in the maxillary structures using the bone-supported expander device by the Finite Element Method. Material and methods: A three- dimensional model was simulated for surgery with a LeFort I osteotomy with pterygomaxillary disjunction using a bone-supported device model for the 1mm aperture. The results showed a greater opening of the maxilla in the anterior region and a smaller opening in the posterior region. The tension forces showed mainly in all the palatine face and the posterior alveolar bone and tuber, as well as in the epilating zygomatic region above the osteotomy. The stress showed little dissipation for the roots of the molar. The forces of compression were manifested in the pterygoid process and the zygomatic pillar adjacent to the osteotomies, as well as in the expander areas of contact with the palatine bone. The analysis showed that the mo...

Research, Society and Development, 2020

This study compared the acquisition protocols of the Conical Beam Computed Tomography (CBCT) syst... more This study compared the acquisition protocols of the Conical Beam Computed Tomography (CBCT) system, to assess the influence on image accuracy by different voxel sizes and the presence of soft tissue. Tomographic acquisition was performed in a fresh (F) and dry (D) pork jaw with voxel sizes of 0.4, 0.3 and 0.25 mm. The gold standard was obtained by scanning dry jaws covered with barium sulfate with a voxel size of 0.25 mm. The images were treated in the MIMICS® program, and noise areas were removed manually, using a fixed threshold for the purpose of generating 3D printing windows. Each window was virtually overlaid with the gold standard using the MeshLab software, obtaining absolute error values between the meshes, generating a map of discrepancies. Significant differences were found between windows D 0.30 vs. F 0.30, D 0.30 vs. F 0.25, D 0.30 vs. D 0.25, D 0.30 vs. F 0.40, F 0.30 vs. D 0.25, F 0.25 vs. D 0.25, F 0.25 vs. D 0.40, D 0.25 vs. F 0.40, D 0.25 vs. D 0.40 and F 0.40 v...

Resumo Este trabalho propõe um blueprint interdisciplinar para a biofabricação de órgãos que util... more Resumo Este trabalho propõe um blueprint interdisciplinar para a biofabricação de órgãos que utiliza as ideias comuns de simulações como métodos probabilísticos preditivos e cálculos de energia aplicados a dois frameworks: o mecânico e o biológico. Em resumo, o mecânico utilizaria a análise de elementos finitos para observar comportamentos fluidodinâmicos como pressão hidrostática, elasticidade e fluxo de fluidos. Já o biológico utilizaria sistemas complexos de interação intra, inter e extracelular para analisar comportamentos como divisão celular, difusão e quimiotaxia das unidades básicas que compõem o órgão.

We present a detailed step-by-step approach for the low-cost production and surgical implantation... more We present a detailed step-by-step approach for the low-cost production and surgical implantation of cranial prostheses, aimed at restoring aesthetics, cerebral protection, and facilitating neurological rehabilitation. This protocol uses combined scan computed tomography (CT) cross-sectional images, in DICOM format, along with a 3D printing (additive manufacturing) setup. The in-house developed software InVesalius®️ is an open-source tool for medical imaging manipulation. The protocol describes image acquisition (CT scanning) procedures, and image post-processing procedures such as image segmentation, surface/volume rendering, mesh generation of a 3D digital model of the cranial defect and the desired prostheses, and their preparation for use in 3D printers. Furthermore, the protocol describes a detailed powder bed fusion additive manufacturing process, known as Selective Laser Sintering (SLS), using Polyamide (PA12) as feedstock to produce a 3-piece customized printed set per patie...

Journal of 3D Printing in Medicine, 2021

Tweetable abstract #3Dprinting assumed a fundamental role during the #covid-19 #pandemic worldwid... more Tweetable abstract #3Dprinting assumed a fundamental role during the #covid-19 #pandemic worldwide. It establishes as a notorious manufacturing technique in the industry and society and a powerful ally for #future emergencies.

The International Journal of Advanced Manufacturing Technology, 2020

Additive manufacturing (AM) is one of the pillars of Industry 4.0, where automation to create sma... more Additive manufacturing (AM) is one of the pillars of Industry 4.0, where automation to create smart factories is the main target. The hybridization of processes is one of the leading strategies to implement a more flexible, efficient, and interconnected manufacturing environment. Nowadays, different researches are focused on the hybridization of metal AM and subtractive manufacturing (SM). Based on the working principles of AM and SM, it can be established that they are complementary processes. Hence, a synergy between them allows conceiving a unique process. As a result, the advantages are magnified, and the limitations of each one are minimized or eliminated. This review presents the latest developments, challenges, limitations, and future perspectives for the integration between directed energy deposition (DED) and SM. DED is a versatile AM process for metal parts fabrication, where the geometrical complexity is its main advantage. Nevertheless, the low surface quality and the difficult dimensional control of the parts create the need for post-processing. Traditional post-processing involves a higher production time, and the barriers cannot be completely overcome. Then, a hybrid process constitutes a powerful concept to combine both technologies efficiently, to produce complex parts with less waste of material and energy.

Progress in Additive Manufacturing, 2020

Terrae Didatica, 2018

Three-dimensional modeling connects several fields of knowledge, both basic and applied. 3D model... more Three-dimensional modeling connects several fields of knowledge, both basic and applied. 3D models are relevant in educa-tional research because the manipulation of 3D objects favors students' acquisition of spatial vision, but in the Geosciences, there are few didactic publications in Portuguese on the subject. The authors develop an educational research project to produce three-dimensional models of didactic examples of sedimentary basins: the Paraná Basin (Silurian-Upper Cretaceous), the Tau-baté and the São Paulo basins (Neogene). 3D-compatible files will be produced to compose didactic and display material, from maps and geological-structural profiles of certain regional stratigraphic levels of each basin. The research challenges are: (a) to obtain an overview of the available resources for 3D modeling; (b) to evaluate their potential, characteristics, advantages and limitations for applications in Geology and Geosciences; (c) to create computational models of the basins; (...

Virtual Prototyping & Bio Manufacturing in Medical Applications, 2020

Sitientibus Série Ciências Físicas, 2008

Este trabalho é relacionado com a engenharia de reabilitação, e mostra a evolução e a diversidade... more Este trabalho é relacionado com a engenharia de reabilitação, e mostra a evolução e a diversidade de formas e aplicações da física em algumas das técnicas de produção de próteses biomecânicas, seja na definição, construção e projeto da estrutura em seus diversos modelos, seja nos aspectos mecânicos, funcionais e operacionais, a exemplo da construção e do acionamento de próteses para indivíduos com amputação parcial dos membros superiores. O artigo apresenta a construção de dois modelos de próteses de apreensão. Um primeiro modelo do tipo acionamento com um atuador baseado em Shape Memory Alloy - SMA, e estudado através de três protótipos, um artesanal, um feito por usinagem convencional, e um terceiro por prototipagem rápida, sendo este último dedicado e integrado na estrutura da prótese. A proposta do segundo modelo, uma próotese acionada por motor de corrente contínua também é apresentada, sendo este integrado à garra, através de um redutor de velocidade. O projeto do modelo usand...

Revista dos Trabalhos de Iniciação Científica da UNICAMP, 2019

A Engenharia Tecidual é uma área interdisciplinar, em que o conhecimento pode ser aplicado na cri... more A Engenharia Tecidual é uma área interdisciplinar, em que o conhecimento pode ser aplicado na criação, regeneração e aperfeiçoamento de técnicas na medicina para reposição de tecidos. A impressão 3D surge em meio à engenharia tecidual com novas possibilidades, como a impressão a partir de um modelo tridimensional virtual que mimetize uma estrutura biológica. Para o estudo será apresentado um modelo 3D de um suporte de traquéia, que pode vir a ser utilizado no tratamento da doença Traqueomalácia. Desafios para a impressão de um modelo otimizado serão analisados utilizando uma impressora 3D FAB@CTI, presente no CTI Renato Archer.

Surgical Neurology International, 2019

Anais do Encontro Nacional de Engenharia de Produção, 2018

Selective Laser Sintering (SLS), which allows to obtain a desired customized shape, excelent to p... more Selective Laser Sintering (SLS), which allows to obtain a desired customized shape, excelent to prepare implants molds. Thermal processing conditions during Additive Manufacturing (AM) is significant influence on crystallinity and morfology conditions. In this research, we have studied the relationship between SLS parameters and the desired PEEK morphology, roughness and crystallinity. All results showed that the temperature-control of the 3D printing method has a potential influence on the morphology layer by layer and it could be a potential to produce cranial implants, especially due to rough surface presented. However if uncontrolled the cooling temperature can reduce crystallinity probably impacting the 3D structure resistance.

Journal of neuroscience methods, Jan 24, 2018

Neuronavigation provides visual guidance of an instrument during procedures of neurological inter... more Neuronavigation provides visual guidance of an instrument during procedures of neurological interventions, and has been shown to be a valuable tool for accurately positioning transcranial magnetic stimulation (TMS) coils relative to an individual's anatomy. Despite the importance of neuronavigation, its high cost, low portability, and low availability of magnetic resonance imaging facilities limit its insertion in research and clinical environments. We have developed and validated the InVesalius Navigator as the first free, open-source software for image-guided navigated TMS, compatible with multiple tracking devices. A point-based, co-registration algorithm and a guiding interface were designed for tracking any instrument (e.g. TMS coils) relative to an individual's anatomy. Localization, precision errors, and repeatability were measured for two tracking devices during navigation in a phantom and in a simulated TMS study. Errors were measured in two commercial navigated TMS...

Materials science & engineering. C, Materials for biological applications, 2018

Poly(3-hydroxybutyrate) (PHB) is a biodegradable and thermoprocessable biopolymer, making it a pr... more Poly(3-hydroxybutyrate) (PHB) is a biodegradable and thermoprocessable biopolymer, making it a promising candidate for applications in tissue engineering. In the present study a structural characterization and in vitro evaluation were performed on PHB scaffolds produced by additive manufacturing via selective laser sintering (SLS), followed by post-printing functionalization with osteogenic growth peptide (OGP) and its C-terminal sequence OGP(10-14). The PHB scaffolds were characterized, including their morphology, porosity, thermal and mechanical properties, moreover OGP release. The results showed that SLS technology allowed the sintering of the PHB scaffolds with a hierarchical structure with interconnected pores and intrinsic porosity (porosity of 55.8 ± 0.7% and pore size in the 500-700 μm range), and good mechanical properties. Furthermore, the SLS technology did not change thermal properties of PHB polymer. The OGP release profile showed that PHB scaffold promoted a controlle...

Journal of 3D Printing in Medicine, 2017

Information technology (IT) is ubiquitous in recent human existence. The aim of this article is t... more Information technology (IT) is ubiquitous in recent human existence. The aim of this article is to present some basic concepts and specific demands that biofabrication may place on IT. Some of these technologies are already available, with a need for improvement, while others will need to be newly developed. Technologies that clearly, precisely and unambiguously specify a tissue or organ are unavailable. A move from expensive in vitro and in vivo assays toward in silico technologies will allow for exhaustive tests and optimization of human substitutes by means of computer biological systems. To complete this substitution, biofabrication lines shall be established; integrating what was planned and designed into physical processes executed by automatic machines. Biofabrication will impose great challenges, since many tools will need to be developed by engineers together with biologists. Many other concerns and challenges will be faced in the path to an autonomous biofabrication line, ...

Modelling, Simulation and Identification / 841: Intelligent Systems and Control, 2016

Cardiovascular disease remains as one of the main problems in contemporary health care worldwide.... more Cardiovascular disease remains as one of the main problems in contemporary health care worldwide. Several studies of the cardiac prostheses have been held since 60s with the advent of cardiopulmonary bypass. The mechanical properties of blood vessels, arteries and valves depend on collagen and elastic fibers, as well as on smooth muscle cells and ground substances. Many works about three-dimensional finite element model of the arterial wall segment and the heart valves assume the biological material to be homogeneous and isotropic. This configuration is a simplified way to reduce the complexity of biological structures. The primary purpose of this study was to assess the effects of fiber design and orientation on the stress distribution in a 3D model for cardiovascular implants and predict the elastic modulus of scaffolds designed.