Examinando por Materia "animal"
Mostrando 1 - 10 de 10
Resultados por página
Opciones de ordenación
Ítem Biomechanics of the canine mandible during bone transport distraction osteogenesis(ASME, 2014-11-01) Zapata, Uriel; Dechow, Paul C.; Watanabe, Ikuya; Elsalanty, Mohammed E.; Opperman, Lynne A.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Bioingeniería GIB (CES – EAFIT)This study compared biomechanical patterns between finite element models (FEMs) and a fresh dog mandible tested under molar and incisal physiological loads in order to clarify the effect of the bone transport distraction osteogenesis (BTDO) surgical process. Three FEMs of dog mandibles were built in order to evaluate the effects of BTDO. The first model evaluated the mandibular response under two physiological loads resembling bite processes. In the second model, a 5.0 cm bone defect was bridged with a bone transport reconstruction plate (BTRP). In the third model, new regenerated bony tissue was incorporated within the defect to mimic the surgical process without the presence of the device. Complementarily, a mandible of a male American foxhound dog was mechanically tested in the laboratory both in the presence and absence of a BTRP, and mechanical responses were measured by attaching rosettes to the bone surface of the mandible to validate the FEM predictions. The relationship between real and predicted values indicates that the stress patterns calculated using FEM are a valid predictor of the biomechanics of the BTDO procedures. The present study provides an interesting correlation between the stiffness of the device and the biomechanical response of the mandible affected for bone transport. Copyright © 2014 by ASME.Ítem Biomechanics of the canine mandible during bone transport distraction osteogenesis(ASME, 2014-11-01) Zapata, Uriel; Dechow, Paul C.; Watanabe, Ikuya; Elsalanty, Mohammed E.; Opperman, Lynne A.; Zapata, Uriel; Dechow, Paul C.; Watanabe, Ikuya; Elsalanty, Mohammed E.; Opperman, Lynne A.; Universidad EAFIT. Departamento de Ingeniería de Producción; Materiales de IngenieríaThis study compared biomechanical patterns between finite element models (FEMs) and a fresh dog mandible tested under molar and incisal physiological loads in order to clarify the effect of the bone transport distraction osteogenesis (BTDO) surgical process. Three FEMs of dog mandibles were built in order to evaluate the effects of BTDO. The first model evaluated the mandibular response under two physiological loads resembling bite processes. In the second model, a 5.0 cm bone defect was bridged with a bone transport reconstruction plate (BTRP). In the third model, new regenerated bony tissue was incorporated within the defect to mimic the surgical process without the presence of the device. Complementarily, a mandible of a male American foxhound dog was mechanically tested in the laboratory both in the presence and absence of a BTRP, and mechanical responses were measured by attaching rosettes to the bone surface of the mandible to validate the FEM predictions. The relationship between real and predicted values indicates that the stress patterns calculated using FEM are a valid predictor of the biomechanics of the BTDO procedures. The present study provides an interesting correlation between the stiffness of the device and the biomechanical response of the mandible affected for bone transport. Copyright © 2014 by ASME.Ítem Effect of chemical composition and microstructure on the mechanical behavior of fish scales from Megalops Atlanticus(ELSEVIER SCIENCE BV, 2016-03-01) Gil-Duran, S.; Arola, D.; Ossa, E.A.; Gil-Duran, S.; Arola, D.; Ossa, E.A.; Universidad EAFIT. Departamento de Ingeniería de Producción; Materiales de IngenieríaThis paper presents an experimental study of the composition, microstructure and mechanical behavior of scales from the Megalops Atlanticus (Atlantic tarpon). The microstructure and composition were evaluated by Scanning Electron Microscopy (SEM) and RAMAN spectroscopy, respectively. The mechanical properties were evaluated in uniaxial tension as a function of position along the length of the fish (head, mid-length and tail). Results showed that the scales are composed of collagen and hydroxyapatite, and these constituents are distributed within three well-defined layers from the bottom to the top of the scale. The proportion of these layers with respect to the total scale thickness varies radially. The collagen fibers are arranged in plies with different orientations and with preferred orientation in the longitudinal direction of the fish. Results from the tensile tests showed that scales from Megalops Atlanticus exhibit variations in the elastic modulus as a function of body position. Additional testing performed with and without the highly mineralized top layers of the scale revealed that the mechanical behavior is anisotropic and that the highest strength was exhibited along the fish length. Furthermore, removing the top mineralized layers resulted in an increase in the tensile strength of the scale. © 2015 Elsevier Ltd.Ítem The global impact of sutures assessed in a finite element model of a macaque cranium(WILEY-LISS, 2010-09-01) Wang, Qian; Smith, Amanda L.; Strait, David S.; Wright, Barth W.; Richmond, Brian G.; Grosse, Ian R.; Byron, Craig D.; Zapata, Uriel; Universidad EAFIT. Departamento de Ingeniería Mecánica; Bioingeniería GIB (CES – EAFIT)The biomechanical significance of cranial sutures in primates is an open question because their global impact is unclear, and their material properties are difficult to measure. In this study, eight suture-bone functional units representing eight facial sutures were created in a finite element model of a monkey cranium. All the sutures were assumed to have identical isotropic linear elastic material behavior that varied in different modeling experiments, representing either fused or unfused sutures. The values of elastic moduli employed in these trials ranged over several orders of magnitude. Each model was evaluated under incisor, premolar, and molar biting conditions. Results demonstrate that skulls with unfused sutures permitted more deformations and experienced higher total strain energy. However, strain patterns remained relatively unaffected away from the suture sites, and bite reaction force was likewise barely affected. These findings suggest that suture elasticity does not substantially alter load paths through the macaque skull or its underlying rigid body kinematics. An implication is that, for the purposes of finite element analysis, omitting or fusing sutures is a reasonable modeling approximation for skulls with small suture volume fraction if the research objective is to observe general patterns of craniofacial biomechanics under static loading conditions. The manner in which suture morphology and ossification affect the mechanical integrity of skulls and their ontogeny and evolution awaits further investigation, and their viscoelastic properties call for dynamic simulations. © 2010 Wiley-Liss, Inc.Ítem Impacto de la adopción de una mascota en las percepciones de bienestar físico y emocional(2019-04-01) M. LONDOÑO; M. LEMOS-HOYOS; J. OREJUELA; M. LONDOÑO; M. LEMOS-HOYOS; J. OREJUELA; Universidad EAFIT. Departamento de Humanidades; El Método Analítico y sus Aplicaciones en las Ciencias Sociales y Humanas (EAFIT – Ude A)Este estudio indaga por las percepciones de un grupo de personas que van a adoptar una mascotaÍtem Impacto de la adopción de una mascota en las percepciones de bienestar físico y emocional(2019-04-01) Londoño, Mariana; Lemos-Hoyos, Mariantonia; Orejuela, J.; Londoño, Mariana; Lemos-Hoyos, Mariantonia; Orejuela, J.; Universidad EAFIT. Departamento de Humanidades; Estudios en PsicologíaEste estudio indaga por las percepciones de un grupo de personas que van a adoptar una mascotaÍtem The limiting layer of fish scales: Structure and properties(ELSEVIER SCI LTD, 2018-02-01) Arola D.; Murcia S.; Stossel M.; Pahuja R.; Linley T.; Devaraj A.; Ramulu M.; Ossa E.A.; Wang J.; Arola D.; Murcia S.; Stossel M.; Pahuja R.; Linley T.; Devaraj A.; Ramulu M.; Ossa E.A.; Wang J.; Universidad EAFIT. Departamento de Ingeniería de Producción; Materiales de IngenieríaFish scales serve as a flexible natural armor that have received increasing attention across the materials community. Most efforts in this area have focused on the composite structure of the predominately organic elasmodine, and limited work addresses the highly mineralized external portion known as the Limiting Layer (LL). This coating serves as the first barrier to external threats and plays an important role in resisting puncture. In this investigation the structure, composition and mechanical behavior of the LL were explored for three different fish, including the arapaima (Arapaima gigas), the tarpon (Megalops atlanticus) and the carp (Cyprinus carpio). The scales of these three fish have received the most attention within the materials community. Features of the LL were evaluated with respect to anatomical position to distinguish site-specific functional differences. Results show that there are significant differences in the surface morphology of the LL from posterior and anterior regions in the scales, and between the three fish species. The calcium to phosphorus ratio and the mineral to collagen ratios of the LL are not equivalent among the three fish. Results from nanoindentation showed that the LL of tarpon scales is the hardest, followed by the carp and the arapaima and the differences in hardness are related to the apatite structure, possibly induced by the growth rate and environment of each fish.STATEMENT OF SIGNIFICANCE: The natural armor of fish, turtles and other animals, has become a topic of substantial scientific interest. The majority of investigations have focused on the more highly organic layer known as the elasmodine. The present study addresses the highly mineralized external portion known as the Limiting Layer (LL). Specifically, the structure, composition and mechanical behavior of the LL were explored for three different fish, including the arapaima (Arapaima gigas), the tarpon (Megalops atlanticus) and the carp (Cyprinus carpio). Results show that there are significant differences in the surface morphology of the LL from posterior and anterior regions in the scales, and between the three species. In addition, the composition of the LL is also unique among the three fish. Results from nanoindentation showed that the LL of tarpon scales is the hardest, followed by the carp and the arapaima and the differences in hardness are related to the apatite structure, possibly induced by the growth rate and environment of each fish. In addition, a new feature was indentified in the LL, which has not been discussed before. As such, we feel this work is unique and makes a significant contribution to the field. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.Ítem Material properties of mandibular cortical bone in the American alligator, Alligator mississippiensis(ELSEVIER SCIENCE INC, 2010-03-01) Zapata, Uriel; Metzger, Keith; Wang, Qian; Elsey, Ruth M.; Ross, Callum F.; Dechow, Paul C.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Bioingeniería GIB (CES – EAFIT)This study reports the elastic material properties of cortical bone in the mandible of juvenile Alligator mississippiensis obtained by using an ultrasonic wave technique. The elastic modulus, the shear modulus, and Poisson's ratio were measured on 42 cylindrical Alligator bone specimens obtained from the lingual and facial surfaces of 4 fresh Alligator mandibles. The data suggest that the elastic properties of alligator mandibular cortical bone are similar to those found in mammals and are orthotropic. The properties most resemble those found in the cortex of mammalian postcranial long bones where the bone is most stiff in one direction and much less stiff in the two remaining orthogonal directions. This is different from cortical bone found in the mandibles of humans and some monkeys, where the bone has greatest stiffness in one direction, much less stiffness in another direction, and an intermediate amount in the third orthogonal direction. This difference suggests a relationship between levels of orthotropy and bending stress. The comparability of these elastic moduli to those of other vertebrates suggest that the high bone strain magnitudes recorded from the alligator mandible in vivo are not attributable to a lower stiffness of alligator mandibular bone. © 2009 Elsevier Inc.Ítem Material properties of the skull layers of the primate parietal bone: A single-subject study(Public Library of Science, 2020-01-01) Zapata, U.; Wang, Q.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Bioingeniería GIB (CES – EAFIT)The outer cortical table of the parietal bone has been commonly used as a calvarial bone graft site for the craniofacial reconstruction. However, little is known about how removing the outer table may affect the function and structure of the inner table, and how the knowledge of the biomechanics and material properties of cortical bones will help the calvarial graft to better integrate into the biological and mechanical functions of its surrounding native tissues. In this study, it was hypothesized that there were significant differences in both density and material properties between inner and outer cortical plates in cranial bones. Twelve cylindrical specimens, including inner-outer layers, of cortical parietal bone of a female baboon were collected. Cortical thicknesses and densities were measured, and elastic properties were assessed using an ultrasonic technique. Results demonstrated remarkable difference in both thickness (t = 8.248, p .0.05) and density (t = 4.926, p.0.05) between inner and outer cortical paired samples. Orthotropic characteristics of the cortical plates were detected as well, these findings suggest that there are differences in biomechanical properties between two surfaces of cranial bones at both tissue and organ levels. How these differences are linked to the stress environments of the inner and outer cranial cortical layers awaits further studies. Further study will greatly enhance our ability to address questions derived from both morphological and craniofacial medicine fields about the development and biomechanics of craniofacial skeletons. © 2020 Zapata, Wang.Ítem Material properties of the skull layers of the primate parietal bone: A single-subject study(Public Library of Science, 2020-01-01) Zapata, U.; Wang, Q.; Zapata, U.; Wang, Q.; Universidad EAFIT. Departamento de Ingeniería de Producción; Materiales de IngenieríaThe outer cortical table of the parietal bone has been commonly used as a calvarial bone graft site for the craniofacial reconstruction. However, little is known about how removing the outer table may affect the function and structure of the inner table, and how the knowledge of the biomechanics and material properties of cortical bones will help the calvarial graft to better integrate into the biological and mechanical functions of its surrounding native tissues. In this study, it was hypothesized that there were significant differences in both density and material properties between inner and outer cortical plates in cranial bones. Twelve cylindrical specimens, including inner-outer layers, of cortical parietal bone of a female baboon were collected. Cortical thicknesses and densities were measured, and elastic properties were assessed using an ultrasonic technique. Results demonstrated remarkable difference in both thickness (t = 8.248, p .0.05) and density (t = 4.926, p.0.05) between inner and outer cortical paired samples. Orthotropic characteristics of the cortical plates were detected as well, these findings suggest that there are differences in biomechanical properties between two surfaces of cranial bones at both tissue and organ levels. How these differences are linked to the stress environments of the inner and outer cranial cortical layers awaits further studies. Further study will greatly enhance our ability to address questions derived from both morphological and craniofacial medicine fields about the development and biomechanics of craniofacial skeletons. © 2020 Zapata, Wang.