Examinando por Materia "ultrasound"

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    Ítem
    Biomechanical characteristics of regenerated cortical bone in the canine mandible
    (WILEY-BLACKWELL, 2011-07-01) Zapata, Uriel; Opperman, Lynne A.; Kontogiorgos, Elias; Elsalanty, Mohammed E.; Dechow, Paul C.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Bioingeniería GIB (CES – EAFIT)
    To test the mechanical properties of regenerate cortical bone created using mandibular bone transport (MBT) distraction, five adult male American foxhound dogs underwent unilateral distraction of the mandible with a novel MBT device placed to linearly repair a 30-35 mm bone defect. The animals were sacrificed 12 weeks after the beginning of the consolidation period. Fourteen cylindrical specimens were taken from the inner (lingual) and outer (buccal) plates of the reconstructed mandible and 21 control specimens were removed from the contralateral aspect of the mandible. The mechanical properties of the 35 cylindrical cortical bone specimens were assessed by using a non-destructive pulse ultrasound technique. Results showed that all of the cortical mechanical properties exhibit higher numerical values on the control side than the MBT regenerate side. In addition, both densities and the elastic moduli in the direction of maximum stiffness of the regenerate cortical bone specimens are higher on the lingual side than the buccal side. Interestingly, there is no statistical difference between elastic modulus (E1 and E2) in orthogonal directions throughout the 35 cortical specimens. The data suggest that not only is the regenerate canine cortical bone heterogeneous, but the elastic mechanical properties tend to approximate transverse isotropy at a tissue level, as opposed to control cortical bone, which is orthotropic. In addition, the elastic mechanical properties are higher not only on the control side but also in the lingual anatomical position, suggesting a stress shielding effect from the presence of the reconstruction plate. © 2011 John Wiley & Sons, Ltd.
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    Bone regeneration and docking site healing after bone transport distraction osteogenesis in the canine mandible
    (W.B. Saunders Ltd, 2012-01-01) Nagashima, L.K.; Rondon-Newby, M.; Zakhary, I.E.; Nagy, W.W.; Zapata, U.; Dechow, P.C.; Opperman, L.A.; Elsalanty, M.E.; Nagashima, L.K.; Rondon-Newby, M.; Zakhary, I.E.; Nagy, W.W.; Zapata, U.; Dechow, P.C.; Opperman, L.A.; Elsalanty, M.E.; Universidad EAFIT. Departamento de Ingeniería de Producción; Materiales de Ingeniería
    Purpose: Bone transport distraction osteogenesis provides a promising alternative to traditional grafting techniques. However, existing bone transport distraction osteogenesis devices have many limitations. The purpose of this research was to test a new device, the mandibular bone transport reconstruction plate, in an animal model with comparable mandible size to humans and to histologically and mechanically examine the regenerate bone. Materials and Methods: Eleven adult foxhounds were divided into an unreconstructed control group of 5 animals and an experimental group of 6 animals. In each animal, a 34-mm segmental defect was created in the mandible. The defect was reconstructed with a bone transport reconstruction plate. Histologic and biomechanical characteristics of the regenerate and unrepaired defect were analyzed and compared with bone on the contralateral side of the mandible after 4 weeks of consolidation. Results: The reconstructed defect was bridged with new bone, with little bone in the control defect. Regenerate density and microhardness were 22.3% and 42.6%, respectively, lower than the contralateral normal bone. Likewise, the anisotropy of the experimental group was statistically lower than in the contralateral bone. Half the experimental animals showed nonunion at the docking site. Conclusion: The device was very stable and easy to install and activate. After 1 month of consolidation, the defect was bridged with new bone, with evidence of active bone formation. Regenerate bone was less mature than the control bone. Studies are underway to identify when the regenerate properties compare with normal bone and to identify methods to augment bone union at the docking site. © 2012 American Association of Oral and Maxillofacial Surgeons.
  • No hay miniatura disponible
    Ítem
    Bone regeneration and docking site healing after bone transport distraction osteogenesis in the canine mandible
    (W.B. Saunders Ltd, 2012-01-01) Nagashima, L.K.; Rondon-Newby, M.; Zakhary, I.E.; Nagy, W.W.; Zapata, U.; Dechow, P.C.; Opperman, L.A.; Elsalanty, M.E.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Bioingeniería GIB (CES – EAFIT)
    Purpose: Bone transport distraction osteogenesis provides a promising alternative to traditional grafting techniques. However, existing bone transport distraction osteogenesis devices have many limitations. The purpose of this research was to test a new device, the mandibular bone transport reconstruction plate, in an animal model with comparable mandible size to humans and to histologically and mechanically examine the regenerate bone. Materials and Methods: Eleven adult foxhounds were divided into an unreconstructed control group of 5 animals and an experimental group of 6 animals. In each animal, a 34-mm segmental defect was created in the mandible. The defect was reconstructed with a bone transport reconstruction plate. Histologic and biomechanical characteristics of the regenerate and unrepaired defect were analyzed and compared with bone on the contralateral side of the mandible after 4 weeks of consolidation. Results: The reconstructed defect was bridged with new bone, with little bone in the control defect. Regenerate density and microhardness were 22.3% and 42.6%, respectively, lower than the contralateral normal bone. Likewise, the anisotropy of the experimental group was statistically lower than in the contralateral bone. Half the experimental animals showed nonunion at the docking site. Conclusion: The device was very stable and easy to install and activate. After 1 month of consolidation, the defect was bridged with new bone, with evidence of active bone formation. Regenerate bone was less mature than the control bone. Studies are underway to identify when the regenerate properties compare with normal bone and to identify methods to augment bone union at the docking site. © 2012 American Association of Oral and Maxillofacial Surgeons.
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    Ítem
    Directional Landscapes: Using Parametric Loudspeakers for Sound Reproduction in Art
    (Taylor and Francis Ltd., 2017-01-01) Alunno, M.; Yarce Botero, A.; Universidad EAFIT. Departamento de Ciencias; Biodiversidad, Evolución y Conservación
    As new technologies appear, the expressive palette of creators broadens. Parametric loudspeakers are one of such new technologies that makes it possible to direct sound as though it were a light beam. Since their debut in the market, they have thus far received little attention from part of the artistic world. Some peculiarities concerning the sound reproduction might explain why musicians in particular are hesitating to use an otherwise highly attractive acoustic innovation. Due to such peculiarities, a proper use of parametric loudspeakers in art must start with investigating a whole array of different topics (i.e. non-linear acoustics and ultrasonic transducers) in order to understand how this technology works and utilize it at its best. The result of our project is ultimately a sound installation that makes use of directional sound to ruminate on issues concerning sound perception and the responsible use of our sound environment. © 2016 Informa UK Limited, trading as Taylor & Francis Group.
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    Ítem
    Directional Landscapes: Using Parametric Loudspeakers for Sound Reproduction in Art
    (Taylor and Francis Ltd., 2017-01-01) Alunno, M.; Yarce Botero, A.; Mecánica Aplicada
    As new technologies appear, the expressive palette of creators broadens. Parametric loudspeakers are one of such new technologies that makes it possible to direct sound as though it were a light beam. Since their debut in the market, they have thus far received little attention from part of the artistic world. Some peculiarities concerning the sound reproduction might explain why musicians in particular are hesitating to use an otherwise highly attractive acoustic innovation. Due to such peculiarities, a proper use of parametric loudspeakers in art must start with investigating a whole array of different topics (i.e. non-linear acoustics and ultrasonic transducers) in order to understand how this technology works and utilize it at its best. The result of our project is ultimately a sound installation that makes use of directional sound to ruminate on issues concerning sound perception and the responsible use of our sound environment. © 2016 Informa UK Limited, trading as Taylor & Francis Group.
  • No hay miniatura disponible
    Ítem
    Directional Landscapes: Using Parametric Loudspeakers for Sound Reproduction in Art
    (Taylor and Francis Ltd., 2017-01-01) Alunno, M.; Yarce Botero, A.; Universidad EAFIT. Escuela de Ciencias; Modelado Matemático
    As new technologies appear, the expressive palette of creators broadens. Parametric loudspeakers are one of such new technologies that makes it possible to direct sound as though it were a light beam. Since their debut in the market, they have thus far received little attention from part of the artistic world. Some peculiarities concerning the sound reproduction might explain why musicians in particular are hesitating to use an otherwise highly attractive acoustic innovation. Due to such peculiarities, a proper use of parametric loudspeakers in art must start with investigating a whole array of different topics (i.e. non-linear acoustics and ultrasonic transducers) in order to understand how this technology works and utilize it at its best. The result of our project is ultimately a sound installation that makes use of directional sound to ruminate on issues concerning sound perception and the responsible use of our sound environment. © 2016 Informa UK Limited, trading as Taylor & Francis Group.
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    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.
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    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 Ingeniería
    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.
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    Ítem
    TRATAMIENTO DE AGUAS RESIDUALES DE LA INDUSTRIA TEXTIL MEDIANTE COAGULACION QUIMICA ACOPLADA A PROCESOS FENTON INTENSIFICADOS CON ULTRASONIDO DE BAJA FRECUENCIA
    (Centro de Ciencias de la Atmosfera, UNAM, 2018-02-01) GIL PAVAS EDISON; Arbelaez, Paula Eliana; Medina, J.; GOMEZ, CARLOS MARIO; GIL PAVAS EDISON; Arbelaez, Paula Eliana; Medina, J.; GOMEZ, CARLOS MARIO; Universidad EAFIT. Departamento de Ingeniería de Procesos; Procesos Ambientales (GIPAB)
    The present study evaluates the sequential treatment of chemical coagulation (CC) followed by the advanced oxidation process (AOP) of Fenton (H2O2/Fe2+) or photoFenton (UV/H2O2/Fe2+) intensified by low frequency ultrasound. Optimization of the pretreatment step through CC by jar test showed that an optimal coagulant (Al-2[SO4](3)) dose of 800 mg/L removed 99 % of turbidity and 53 % of the chemical oxygen demand (COD). The resulting supernatant is used for the AOP evaluation. The statistical analysis of a Box-Behnken response surface design showed that optimal conditions to carry out the US/H2O2/Fe2+ process are: 1 mM de Fe2+, 14 mM de H2O2 and pH 3. Under these conditions the CC coupled to the US/H2O2/Fe2+ process removes 82 % of the COD of the supernatant while the US/UV/H2O2/Fe2+ process eliminates 95 % after 90 min of reaction. The use of ultrasound waves inducing an increase of 10 % in the process efficiency. The mineralization of pollutants during treatment as well as the H2O2 consumption were monitored.
  • No hay miniatura disponible
    Ítem
    TRATAMIENTO DE AGUAS RESIDUALES DE LA INDUSTRIA TEXTIL MEDIANTE COAGULACION QUIMICA ACOPLADA A PROCESOS FENTON INTENSIFICADOS CON ULTRASONIDO DE BAJA FRECUENCIA
    (Centro de Ciencias de la Atmosfera, UNAM, 2018-02-01) GIL PAVAS EDISON; Arbelaez, Paula Eliana; Medina, J.; GOMEZ, CARLOS MARIO; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de Procesos
    The present study evaluates the sequential treatment of chemical coagulation (CC) followed by the advanced oxidation process (AOP) of Fenton (H2O2/Fe2+) or photoFenton (UV/H2O2/Fe2+) intensified by low frequency ultrasound. Optimization of the pretreatment step through CC by jar test showed that an optimal coagulant (Al-2[SO4](3)) dose of 800 mg/L removed 99 % of turbidity and 53 % of the chemical oxygen demand (COD). The resulting supernatant is used for the AOP evaluation. The statistical analysis of a Box-Behnken response surface design showed that optimal conditions to carry out the US/H2O2/Fe2+ process are: 1 mM de Fe2+, 14 mM de H2O2 and pH 3. Under these conditions the CC coupled to the US/H2O2/Fe2+ process removes 82 % of the COD of the supernatant while the US/UV/H2O2/Fe2+ process eliminates 95 % after 90 min of reaction. The use of ultrasound waves inducing an increase of 10 % in the process efficiency. The mineralization of pollutants during treatment as well as the H2O2 consumption were monitored.