Viscoelastic properties of alveolar wall.

Sugihara, T.T.; Hildebrandt, J.; Martin, C J

doi:10.1152/jappl.1972.33.1.93

Cited by 34 publications

(25 citation statements)

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“…6 It has also been conjectured that the extent of viscoelasticity is relative to the smooth muscle content of tissue. 7,12,20 Urinary bladder for example, which is predominately comprised of smooth muscle, shows a high degree of rapid SR, while Achilles tendon, which is largely composed of type I collagen, 21 shows minimal SR over a longer period of time. 8,22 This contrast in viscoelastic characteristics between different biological tissues was also observed in the present study.…”

Section: Discussionmentioning

confidence: 99%

“…Several studies have examined stress relaxation and they suggest that the magnitude of SR is directly proportional to smooth muscle content of the tissue. 6,12,13 Smooth muscle can also display SR in the reverse direction, a lesser documented mechanism referred to as ''reverse stress relaxation'' (RSR). 11 This phenomenon occurs after a loss in smooth muscle fiber tension, for example in blood vessel walls following severe hemorrhage, in which a drop in vessel smooth muscle tension is compensated for over a period of minutes by RSR of the fibers.…”

mentioning

confidence: 99%

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Early fracture callus displays smooth muscle‐like viscoelastic properties ex vivo: Implications for fracture healing

McDonald

Dooley

McDonald

et al. 2009

Journal Orthopaedic Research

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Cells of early, fibrous callus in bone fractures possess much alpha smooth muscle actin. This callus contracts and relaxes; however, active and passive components of its force production have yet to be defined. We aimed to establish whether passive viscoelastic properties of early soft fracture callus are smooth muscle-like in nature. Under anesthesia one rib was fractured in rats and calluses removed 7 days later for analysis. Urinary bladder detrusor muscle and Achilles tendon were also resected and analyzed. Force production in these tissues was measured using a force transducer when preparations were immersed in calcium-free Krebs-Henseleit solution (pH 7.4, 228C). Viscoelastic responses were measured in each preparation in response to 50 mN increases and decreases in force after achieving basal tissue tension by preconditioning. Callus, bladder, and tendon all displayed varying, reproducible degrees of stress relaxation (SR) and reverse stress relaxation (RSR) (n ¼ 7 for all groups). Hysteresis was observed in callus, with the first SR response significantly larger than that produced in subsequent stretches (p < 0.05). Callus SR responses were greater than tendon (p < 0.001) but less than bladder (p < 0.001). Callus RSR responses were greater than tendon (p < 0.001), but no significant difference was seen between RSR of callus and bladder. We concluded that early, soft callus displayed significant SR and RSR phenomena similar to smooth muscle tissue, and SR and RSR may be important in maintenance of static tension in early callus by promoting osteogenesis and fracture healing. ß

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Early fracture callus displays smooth muscle‐like viscoelastic properties ex vivo: Implications for fracture healing

McDonald

Dooley

McDonald

et al. 2009

Journal Orthopaedic Research

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“…This is partially caused by the viscoelastic attributes of the tissue [48]; but predominantly caused by the surfactant cycle that aids in the mechanics of breathing [40,43]. Neither of these effects are to be addressed in this preliminary study.…”

Section: Methodsmentioning

confidence: 97%

“…m h ! I IY (48) and " m h P" I IY It is through an understanding of these tangent moduli (48)(49)(50)(51), and how they vary for different BVPs, that one can begin to acquire an intuition about this material model and its behavior.…”

Section: Methodsmentioning

confidence: 99%

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

Freed¹,

Einstein²

2011

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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.

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“…However, like all other biological materials, the elastic properties of the lung are anything but ''ideal,'' insofar as global stress and tissue microarchitecture are sensitive to length history and time (6). Consequently, at a given end-inspiratory volume, transpulmonary pressure (a measure of lung parenchymal stress) varies with the rate of lung inflation as well as the initial or starting volume (7,8). On a smaller scale, yet one that is relevant from a mechanotransduction and hence tissue injury perspective, rate and amplitude of deformation exert profound effects on cytoskeletal fluidity and hence cytoskeletal architecture (9,10), on the hydration state of ground substance (11,12), and consequently on a host of enzymes such as metalloproteinases, which are involved in inflammatory signaling and tissue remodeling responses (13).…”

mentioning

confidence: 99%