Direct modification of FE meshes preserving group information

Nowadays, the mainstream methodology for product behavior analysis and improvement relies on the fol-lowing steps: 1) conceptual solution proposal and CAD prototyping, 2) mesh model creation for Finite Element (FE) analysis, 3) preparation of complex mesh model as specification of semantic information for particular behavior study, 4) advanced FE simu-lation, 5) result analysis and optimization loops. The semantics relative to the simulation model are often associated to mesh entities through the use of so-called mesh groups. During the optimization phase, geometric modifications are generally performed on the CAD model. This requires a complete updating of the FE mesh model repeating all the above listed FE mesh preparation (re-creation of all the groups). In the present paper, we propose a new framework for CAD-less FE analysis. It comes to apply shape modi-fication operators directly to the FE mesh while ex-ploiting and maintaining the available FE semantic information. As a result, multiple steeps of the design process loop, as CAD and mesh model generation, mesh group creation, are avoided. In this paper, we focus on two 3D mesh modification operators: the planar cracking and the drillin

Research on real-time physics-based deformation for haptic-enabled medical simulation

This study developed a multiple effective visuo-haptic surgical engine to handle a variety of surgical manipulations in real-time. Soft tissue models are based on biomechanical experiment and continuum mechanics for greater accuracy. Such models will increase the realism of future training systems and the VR/AR/MR implementations for the operating room

Direct modification of FE meshes preserving group information

Nowadays, the mainstream methodology for product behavior analysis and improvement relies on the fol-lowing steps: 1) conceptual solution proposal and CAD prototyping, 2) mesh model creation for Finite Element (FE) analysis, 3) preparation of complex mesh model as specification of semantic information for particular behavior study, 4) advanced FE simu-lation, 5) result analysis and optimization loops. The semantics relative to the simulation model are often associated to mesh entities through the use of so-called mesh groups. During the optimization phase, geometric modifications are generally performed on the CAD model. This requires a complete updating of the FE mesh model repeating all the above listed FE mesh preparation (re-creation of all the groups). In the present paper, we propose a new framework for CAD-less FE analysis. It comes to apply shape modi-fication operators directly to the FE mesh while ex-ploiting and maintaining the available FE semantic information. As a result, multiple steeps of the design process loop, as CAD and mesh model generation, mesh group creation, are avoided. In this paper, we focus on two 3D mesh modification operators: the planar cracking and the drillin

Brain and Human Body Modeling

This open access book describes modern applications of computational human modeling with specific emphasis in the areas of neurology and neuroelectromagnetics, depression and cancer treatments, radio-frequency studies and wireless communications. Special consideration is also given to the use of human modeling to the computational assessment of relevant regulatory and safety requirements. Readers working on applications that may expose human subjects to electromagnetic radiation will benefit from this book’s coverage of the latest developments in computational modelling and human phantom development to assess a given technology’s safety and efficacy in a timely manner. Describes construction and application of computational human models including anatomically detailed and subject specific models; Explains new practices in computational human modeling for neuroelectromagnetics, electromagnetic safety, and exposure evaluations; Includes a survey of modern applications for which computational human models are critical; Describes cellular-level interactions between the human body and electromagnetic fields

Fluorescence enhanced optical tomography on breast phantoms with measurements using a gain modulated intensified CCD imaging system

Fluorescence-enhanced optical imaging using near-infrared (NIR) light developed for in-vivo molecular targeting and reporting of cancer provides promising opportunities for diagnostic imaging. However, prior to the administration of unproven contrast agents, the benefits of fluorescence-enhanced optical imaging must be assessed in feasibility phantom studies. A novel intensified charge-coupled device (ICCD) imaging system has been developed to perform 3-D fluorescence tomographic imaging in the frequency-domain using near-infrared contrast agents. This study is unique since it (i) employs a large tissue-mimicking phantom (~1087 cc), which is shaped and sized to resemble a female breast and part of the extended chest wall region, and (ii) enables rapid data acquisition in the frequency-domain by using a gain-modulated ICCD camera. Diagnostic 3-D fluorescence-enhanced optical tomography is demonstrated using 0.5-1 cc single and multiple targets contrasted from their surrounding by ??M concentrations of Indocyanine green (ICG) in the breast-shaped phantom (10 cm diameter), under varying conditions of target-to-background absorption contrast ratios (1:0 and 100:1) and target depths (up to 3 cm deep). Boundary surface fluorescence measurements of referenced amplitude and phase shift were used along with the coupled diffusion equation of light propagation in order to perform 3-D image reconstructions using the approximate extended Kalman filter (AEKF) algorithm, and hence differentiate the target from the background based on fluorescent optical contrast. Detection of single and multiple targets is demonstrated under various conditions of target depths (up to 2 cm deep), absorption optical contrast ratio (1:0 and 100:1), target volumes (0.5-1 cc), and multiple targets (up to three 0.5 cc targets). The feasibility of 3-D image reconstructions from simultaneous multiple point excitation sources are presented. Preliminary lifetime imaging studies with 1:2 and 2:1 optical contrast in fluorescence lifetime of the contrast agents is also demonstrated. The specificity of the optical imager is further assessed from homogeneous phantom studies containing no fluorescently contrasted targets. While nuclear imaging currently provides clinical diagnostic opportunities using radioactive tracers, molecular targeting of tumors using non-ionizing NIR contrast agents tomographically imaged using the frequency-domain ICCD imaging system could possibly become a new method of diagnostic imaging

PRELIMINARY FINDINGS OF A POTENZIATED PIEZOSURGERGICAL DEVICE AT THE RABBIT SKULL

The number of available ultrasonic osteotomes has remarkably increased. In vitro and in vivo studies have revealed differences between conventional osteotomes, such as rotating or sawing devices, and ultrasound-supported osteotomes (Piezosurgery®) regarding the micromorphology and roughness values of osteotomized bone surfaces. Objective: the present study compares the micro-morphologies and roughness values of osteotomized bone surfaces after the application of rotating and sawing devices, Piezosurgery Medical® and Piezosurgery Medical New Generation Powerful Handpiece. Methods: Fresh, standard-sized bony samples were taken from a rabbit skull using the following osteotomes: rotating and sawing devices, Piezosurgery Medical® and a Piezosurgery Medical New Generation Powerful Handpiece. The required duration of time for each osteotomy was recorded. Micromorphologies and roughness values to characterize the bone surfaces following the different osteotomy methods were described. The prepared surfaces were examined via light microscopy, environmental surface electron microscopy (ESEM), transmission electron microscopy (TEM), confocal laser scanning microscopy (CLSM) and atomic force microscopy. The selective cutting of mineralized tissues while preserving adjacent soft tissue (dura mater and nervous tissue) was studied. Bone necrosis of the osteotomy sites and the vitality of the osteocytes near the sectional plane were investigated, as well as the proportion of apoptosis or cell degeneration. Results and Conclusions: The potential positive effects on bone healing and reossification associated with different devices were evaluated and the comparative analysis among the different devices used was performed, in order to determine the best osteotomes to be employed during cranio-facial surgery