Viscoelastic Model for Lung Parenchyma for Multi-Scale Modeling of Respiratory System Phase I: Hypo-Elastic Model for CFD Implementation

Abstract

An isotropic constitutive model for the parenchyma of lung has been derived from the theory of hypo-elasticity. The intent is to use it to represent the mechanical response of this soft tissue in sophisticated, computational, fluid-dynamic models of the lung. This demands that the continuum model be accurate, yet simple and efficient. An objective algorithm for its numeric integration is provided. The response of the model is determined for several boundary-value problems whose experiments are used for material characterization. The £ First annual report to Pacific Northwest National Laboratory from Saginaw Valley State University reporting on progress made under grant number 136492. The project described was supported by Award Number R01HL073598 from the National Heart, Lung, and Blood Institute to Pacific Northwest National Laboratory. The content is solely the responsibility of the author and does not necessarily reflect the official views of the National Heart, Lung, and Blood Institute or the National Institutes of Health.2 effective elastic, bulk, and shear moduli, and Poisson's ratio, as tangent functions, are also derived. The model is characterized against published experimental data for lung.A bridge between this continuum model and a dodecahedral model of alveolar geometry is investigated, with preliminary findings being reported.

Viscoelastic Model for Lung Parenchyma for Multi-Scale Modeling of Respiratory System, Phase II: Dodecahedral Micro-Model

“…(1) for describing the shear response in lung agrees very well with experimental observations [19], as shown in Fig. 2.…”

“…In the first annual report for this project [19], the authors derived a hypo-elastic theory for parenchyma, whose findings are published in [20]. The resulting model is characterized by four material parameters: the two Lamé constants, and , and their hypo-elastic analogs,˛andˇ, which are the so- called Fung constants.…”

“…Three, elastic, tangent responses have been established by applying this experimental protocol to our hypo-elastic material model for parenchyma [19,20].…”

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AbstractIn the first year of this contractual effort a hypo-elastic constitutive model was developed and shown to have great potential in modeling the elastic response of parenchyma [19,20]. This model resides at the macroscopic level of the continuum.

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Inhibiting SIRT-2 by AK-7 restrains airway inflammation and oxidative damage promoting lung resurgence through NF-kB and MAP kinase signaling pathway

“…Furthermore, tissue sections were dehydrated through ascending grades of acetone and dried using a desiccator for 48 h. Tissue was attached to the specimen holders and coated with conductive gold film of roughly 30 nm in thickness. The tissues were further scanned and imaged with a Zeiss Sigma 300 SEM (FEG Oberkochen, Germany) in the secondary electron (SE) and backscattered electron (BSE) modes ( 44 ).…”