Download
1 / 1
10 likes | 223 Views
Transition of Mechanical Environment What is an Optimal Fixation Size? How do Cells Respond to Stress Gradients? Few Studies on Cellular Responses to Gradients of Solid Mechanical Stresses. Stretch. 5%. 10%. 15%. 20%. 25%. R i = r i = 1.0 R o = 2.0.
E N D
Transition of Mechanical Environment • What is an Optimal Fixation Size? • How do Cells Respond to Stress Gradients? • Few Studies on Cellular Responses toGradients of Solid Mechanical Stresses Stretch 5% 10% 15% 20% 25% Ri = ri = 1.0 Ro = 2.0 Skin Biopsy Arthroscopy Stent Deployment Circumferentially Stiffer Case Isotropic Case Radially Stiffer Case Procedural Failure Wound Healing Suture Success? Prolonged Hospital Stays Finite DeformationModeling PredictableStress Distributions In VitroExperiments Fixation (Zero-displacement)Sutures, Wound Healing,Apposition of Stent Failure? Ri, ri 0.001 0.5 1.0 1.5 Defect Fixation Ro = 2.0 Stretch: 10% Defect (Traction-free) Circumferentially Stiffer Case Isotropic Case Radially Stiffer Case • Theoretical Framework (David & Humphrey 2004) • Cauchy Stress • Fung-type Exponential Pseudostrain-energy Function • Equilibrium Equation • Boundary Conditions • Outer Boundar t0: Uniform Radial Stress • Inner Boundary (Zero-displacement) lI: Principal Stretch ratio Reference EII: Green Strain Ri Ro David, G., Humphrey, J. D., 2004. Redistribution of stress due to a circular hole in a nonlinear anisotropic membrane. Journal of Biomechanics 37, 1197-1203 c, ci: Material Parameters Rectangular MembraneStretch Apparatus Circular Membrane Stretch Apparatus (R, Q) (r, q) ri ro Ro: Outer Radius Ri: Inner Radius ro: Outer Radius ri: Inner Radius Reference Configuration Deformed Configuration Elastic Response of Thin Circular Membrane tqq trr Stress gradients in circular membranous tissues with central fixationsDaisuke Mori, Guido David, Jay D Humphrey, and James E Moore Jr.Texas A&M University, Department of Biomedical Engineering Introduction Results Discussion • Medical Interventions Including Minimally Invasive Techniques • Effect of Stretch Ratio Induce Changes in Mechanical Environment Risk of: • How do Cells Respond to the Complex Stress EnvironmentsFollowing Interventional Procedures? • Stress Patterns Depend on a Defect or Fixation • Effect of Size of Fixation Future Direction Methods • Experiments of Cellular Reactions to StressGradients Following Interventional Procedures • Rigid Fixations Play an Important Role in the Distribution of Stress and Strain in a Manner Different From Tissue Defects. • Stress and its Gradients due to Interventional Treatments may Depend on the Size of Fixation, as well as the Material Behavior of the Tissue. • Material Parameters
