The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Agnaldo L. Silva-filho - One of the best experts on this subject based on the ideXlab platform.
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Computational modeling approach to study the effects of fetal head flexion during vaginal delivery
American Journal of Obstetrics and Gynecology, 2010Co-Authors: Marco Parente, Renato Natal Jorge, T. Mascarenhas, António Fernandes, Agnaldo L. Silva-filhoAbstract:Objective The purpose of this study was to investigate the influence of fetal head flexion during vaginal delivery with a 3-dimensional computational finite element model. Study Design A finite element model of the pelvic Skeletal Structure, pelvic floor, and fetus was developed. The movements of the fetus during birth were simulated in engagement, descent, flexion, internal rotation, and extension of the fetal head. The opposite forces against the fetal descendent and the stress of the pelvic floor muscles were obtained on simulations with different degrees of head flexion. Results The simulated increase in fetal head flexion is associated with lower values of opposite forces against the fetal descent. The descending fetus with abnormal head flexion also meets resistance in later stations. Lower stress on the pelvic floor was demonstrated with simulated increase in fetal head flexion during vaginal delivery. Conclusion This analytic evidence suggests that the fetal head flexion during vaginal delivery may facilitate birth and protect the pelvic floor.
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Computational modeling approach to study the effects of fetal head flexion during vaginal delivery.
American journal of obstetrics and gynecology, 2010Co-Authors: Marco P Parente, T. Mascarenhas, Renato M Natal Jorge, António A Fernandes, Agnaldo L. Silva-filhoAbstract:The purpose of this study was to investigate the influence of fetal head flexion during vaginal delivery with a 3-dimensional computational finite element model. A finite element model of the pelvic Skeletal Structure, pelvic floor, and fetus was developed. The movements of the fetus during birth were simulated in engagement, descent, flexion, internal rotation, and extension of the fetal head. The opposite forces against the fetal descendent and the stress of the pelvic floor muscles were obtained on simulations with different degrees of head flexion. The simulated increase in fetal head flexion is associated with lower values of opposite forces against the fetal descent. The descending fetus with abnormal head flexion also meets resistance in later stations. Lower stress on the pelvic floor was demonstrated with simulated increase in fetal head flexion during vaginal delivery. This analytic evidence suggests that the fetal head flexion during vaginal delivery may facilitate birth and protect the pelvic floor. Copyright 2010 Mosby, Inc. All rights reserved.
L C Hollaway - One of the best experts on this subject based on the ideXlab platform.
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thermoplastic carbon fiber composites could aid solar based power generation possible support system for solar power satellites
Journal of Composites for Construction, 2011Co-Authors: L C HollawayAbstract:Solar power has merit as a renewable source of energy; it is the largest asset available for consumption on Earth and is limitless. There have been many ideas proposed to beam solar power to Earth; all have been dependent upon the provision of a backing frame to support solar panels, photovoltaic cells, and transmission. This paper suggests one type of rigid deployable Skeletal Structure and its material of manufacture to form the backing frame of solar panel systems; the Structure takes the form of a Skeletal double-layer tetrahedral system. The composite material is polyethersulphone thermoplastic polymer reinforced with carbon fiber (CF). This paper also discusses the hostile environment of space in relation to the fiber-reinforced polymer (FRP) composite material, with special reference to the thermal response. Finally, it suggests the alternate possibility of using a rigidized inflatable flexible Skeletal Structure and, as far as is possible, compares (a) the relative cost of transferring the two str...
Karl G Lark - One of the best experts on this subject based on the ideXlab platform.
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genetic basis for systems of Skeletal quantitative traits principal component analysis of the canid skeleton
Proceedings of the National Academy of Sciences of the United States of America, 2002Co-Authors: Kevin Chase, David R Carrier, Frederick R Adler, T Jarvik, Elaine A Ostrander, Travis D Lorentzen, Karl G LarkAbstract:Evolution of mammalian Skeletal Structure can be rapid and the changes profound, as illustrated by the morphological diversity of the domestic dog. Here we use principal component analysis of Skeletal variation in a population of Portuguese Water Dogs to reveal systems of traits defining Skeletal Structures. This analysis classifies phenotypic variation into independent components that can be used to dissect genetic networks regulating complex biological systems. We show that unlinked quantitative trait loci associated with these principal components individually promote both correlations within Structures (e.g., within the skull or among the limb bones) and inverse correlations between Structures (e.g., skull vs. limb bones). These quantitative trait loci are consistent with regulatory genes that inhibit growth of some bones while enhancing growth of others. These systems of traits could explain the Skeletal differences between divergent breeds such as Greyhounds and Pit Bulls, and even some of the Skeletal transformations that characterize the evolution of hominids.
Isamu Kashima - One of the best experts on this subject based on the ideXlab platform.
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Evaluating two-dimensional Skeletal Structure parameters using radiological bone morphometric analysis
Oral Radiology, 2005Co-Authors: Kensuke Asa, Takashi Sakurai, Satsuki Kumasaka, Isamu KashimaAbstract:Objectives To investigate the reliability of two-dimensional (2D) Skeletal Structure parameters obtained using radiological bone morphometric analysis.
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structuring of parameters for assessing vertebral bone strength by star volume analysis using a morphological filter
Journal of Bone and Mineral Metabolism, 2001Co-Authors: Tetsuo Tanaka, Takashi Sakurai, Isamu KashimaAbstract:Based on the relationship between bone strength, trabecular Skeletal Structure, and bone mineral density (BMD), Structure parameters for assessing vertebral bone strength were studied using 18 cancellous bone blocks from the third lumbar vertebra of elderly persons. The trabecular bone pattern of each bone block was binarized into a trabecular Skeletal pattern by computed radiography (CR) using a morphological filter. The binarized trabecular Skeletal pattern was quantified into a trabecular Skeletal pixel percentage (SKP; volume parameter of the trabecular Skeletal signal component) and trabecular Skeletal star volume (Vt; connection parameter of the trabecular Skeletal Structure) by star volume analysis. Then, the BMD and elasticity of each bone block were measured by dual X-ray absorptiometry and mechanical tests to determine the correlation between SKP and Vt. In the present study, no significant correlations were observed between BMD and elasticity. Elasticity differed greatly between some bone blocks even though BMD was essentially the same. Grid-like Skeletal patterns consisting of vertical and horizontal continuous lines showed higher elasticity. SKP showed higher correlations with elasticity than BMD in subset (n = 2–7) and sumset images, although the fluctuation range was narrow. Meanwhile, Vt showed higher correlations with elasticity than SKP in subset (n = 1–6) and sumset images. Vt showed stronger correlations with elasticity than SKP. This fact indicates that strong relationships exist between the connectivity of trabecular Skeletal Structure and bone strength. Because the SKP–BMD and Vt–BMD correlations are weak, the influences exerted by SKP and Vt seem to be independent of the influence of BMD on the bone strength of vertebra obtained from persons with advanced age. These results indicate that SKP and Vt obtained by star volume analysis using a morphological filter are effective as Structure parameters for analyzing the bone quality of lumbar vertebra.
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Skeletal image for index of bone strength in the radiographic trabecular pattern
Oral Radiology, 1998Co-Authors: Tsutomu Iizuka, Takashi Sakurai, Isamu KashimaAbstract:The purpose of this study is to investigate the relationship between the geometric Structure of bone trabeculae and internal stress distributions and to demonstrate the ability of mathematical morphology to produce a representative two-dimensional structural image of a calcaneus. A finite element analysis was conducted to examine the relationship between the Structure of bone trabeculae and the internal stress distributions using a dried cadaver calcaneus of a 60 year old male. Furthermore, morphological processing was carried out on the clinical images of a normal and an abnormal calcaneus using digital computed radiographic information to analyze the relationship between the geometric and the Skeletal Structures of bone trabeculae using both an osteoporotic and a normal patient. The Skeletal Structure of normal calcaneal trabeculae, obtained by mathematical morphologic processing, approximated the macroscopic pattern on the sagittal section and the principal stress distribution. The differences in the derived Skeletal Structure between normal and abnormal calcanei were visualized on binary images obtained by morphological processing. The Skeletal pattern of bone is related to the strength of bone, and furthermore, as the Skeletal pattern obtained by the mathematical morphology process was comparable to the actual trabecular Structure present, mathematical morphologic Skeletal patterns may be useful indicators of bone strength.
Yoky Matsuoka - One of the best experts on this subject based on the ideXlab platform.
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the act hand design of the Skeletal Structure
International Conference on Robotics and Automation, 2004Co-Authors: Vande M Weghe, Matthew Lee Rogers, M Weissert, Yoky MatsuokaAbstract:Robotic hands built for manipulation are often anthropomorphic but not anatomically accurate. We are constructing an anatomically-correct testbed (ACT) of the human hand to understand its mechanisms, function, and control. We have previously demonstrated that an accurate model of the extensor mechanism in the ACT Hand is crucial in realizing human-like finger movements. Here, we present the design of the bones and joints that form the Skeletal Structure for the ACT Hand. The bones are machined from human bone data, and are accurate in surface shape, mass, and center-of-gravity, while the joints have been designed to match both degrees-of-freedom and passive stiffness. Our evaluation of the assembled index finger confirms the anatomic properties, and reveals the function of some of the peculiar shapes of the finger bones, the necessity of matching the joint passive stiffness properties, and the connections of the extensor mechanism.
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ICRA - The ACT Hand: design of the Skeletal Structure
IEEE International Conference on Robotics and Automation 2004. Proceedings. ICRA '04. 2004, 2004Co-Authors: M. Vande Weghe, Matthew Lee Rogers, M Weissert, Yoky MatsuokaAbstract:Robotic hands built for manipulation are often anthropomorphic but not anatomically accurate. We are constructing an anatomically-correct testbed (ACT) of the human hand to understand its mechanisms, function, and control. We have previously demonstrated that an accurate model of the extensor mechanism in the ACT Hand is crucial in realizing human-like finger movements. Here, we present the design of the bones and joints that form the Skeletal Structure for the ACT Hand. The bones are machined from human bone data, and are accurate in surface shape, mass, and center-of-gravity, while the joints have been designed to match both degrees-of-freedom and passive stiffness. Our evaluation of the assembled index finger confirms the anatomic properties, and reveals the function of some of the peculiar shapes of the finger bones, the necessity of matching the joint passive stiffness properties, and the connections of the extensor mechanism.
