Examinando por Materia "skin"

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    Biomechanical configurations of mandibular transport distraction osteogenesis devices.
    (MARY ANN LIEBERT, INC, 2010-06-01) Zapata U; Elsalanty ME; Dechow PC; Opperman LA; Universidad EAFIT. Departamento de Ingeniería Mecánica; Bioingeniería GIB (CES – EAFIT)
    Mandibular bone transport (MBT) distraction osteogenesis devices are used for achieving reconstruction of mandibular defects in a predictable way, with few complications, less complexity than other alternative surgical procedures, and minimal tissue morbidity. However, selection of appropriate MBT device characteristics is critical for ensuring both their mechanical soundness and their optimal distraction function for each patient's condition. This article assesses six characteristics of currently available MBT devices to characterize their design and function and to classify them in a way that assists the selection of the best device option for each clinical case. In addition, the present work provides a framework for both the biomechanical conception of new devices and the modification of existing ones.
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    Two-dimensional transport analysis of transdermal drug absorption with a non-perfect sink boundary condition at the skin-capillary interface
    (ELSEVIER SCIENCE INC, 2013-07-01) Simon, Laurent; Ospina, Juan; Simon, Laurent; Ospina, Juan; Universidad EAFIT. Departamento de Ciencias; Lógica y Computación
    A transient percutaneous drug absorption model was solved in two dimensions. Clearance of the topically-applied pharmaceutical occured at the skin-capillary boundary. Timolol penetration profiles in the dermal tissue were produced revealing concentration gradients in the directions normal and parallel to the skin surface. Ninety-eight percent of the steady-state flux was reached after 85. h or four time constants. The analytical solution procedure agreed with published results. As the clearance rate increased relative to diffusion, the delivery rate and amount of drug absorbed into the bloodstream increased while the time to reach the equilibrium flux decreased. Researchers can apply the closed-form expressions to simulate the process, estimate key parameters and design devices that meet specific performance requirements. © 2013 Elsevier Inc.
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    Zylerberg, 1985 Contributions of the layer topology and mineral content to the elastic modulus and strength of fish scales
    (ELSEVIER SCIENCE BV, 2018-02-01) Murcia, S.; Miyamoto, Y.; Varma, M.P.; Ossa, A.; Arola, D.
    Fish scales are an interesting natural structural material and their functionality requires both flexibility and toughness. Our previous studies identified that there are spatial variations in the elastic properties of fish scales corresponding to the anatomical regions, and that they appear to be attributed to changes in the microstructure. In the present study, a model is proposed that describes the elastic behavior of elasmoid fish scales in terms of the relative contributions of the limiting layer and both the internal and external elasmodine. The mechanical properties of scales from the Megalops atlanticus (i.e. tarpon) were characterized in tension and compared with predictions from the model. The average error between the predicted and the experimental properties was 7%. It was found that the gradient in mineral content and aspect ratio of the apatite crystals in the limiting layer played the most important roles on the elastic modulus of the scales. Furthermore, misalignment of plies in the external elasmodine from the longitudinal direction was shown to reduce the elastic modulus significantly. This is one approach for modulating the fish scale flexibility for a high mineral content that is required to increase the resistance to puncture. © 2017