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Full-Text Articles in Biomedical Engineering and Bioengineering

Subject-Specific Finite Element Models Of The Human Knee For Transtibial Amputees To Analyze Tibial Cartilage Pressure For Gait, Cycling, And Elliptical Training, Jonathon Stearns Mar 2020

Subject-Specific Finite Element Models Of The Human Knee For Transtibial Amputees To Analyze Tibial Cartilage Pressure For Gait, Cycling, And Elliptical Training, Jonathon Stearns

Master's Theses

It is estimated that approximately 10-12% of the adult population suffers from osteoarthritis (OA), with long reaching burdens personally and socioeconomically. OA also causes mild discomfort to severe pain in those suffering from the disease. The incidence rate of OA for individuals with transtibial amputations is much than average in the tibiofemoral joint (TF). It is well understood that abnormal articular cartilage stress, whether that be magnitude or location, increases the risk of developing OA. Finite element (FE) simulations can predict stress in the TF joint, many studies throughout the years have validated the technology used for this purpose. This …


Matrix Remodeling Accompanies In Vitro Articular Cartilage Spherical Shaping, Nathan Thomas Balcom Jun 2013

Matrix Remodeling Accompanies In Vitro Articular Cartilage Spherical Shaping, Nathan Thomas Balcom

Master's Theses

Introduction: Articular cartilage (AC) is a low friction load bearing material found in synovial joints. The natural repair of damaged tissue is difficult and often requires surgical intervention. With large defects it becomes necessary to match the original tissue geometry. We hypothesized that localized collagen (COL) and/or proteoglycan (PG) remodeling occurs during AC spherical reshaping. The objective of this study was to determine the presence, magnitude and depth dependence of COL and PG remodeling that accompanies AC reshaping. Methods: Full thickness AC blocks (7x7 mm2 surface area) were harvested from the ridges of the patellofemoral groove of immature (1-3 …


Viscoelastic Anisotropic Finite Element Mixture Model Of Articular Cartilage Using Viscoelastic Collagen Fibers And Validation With Stress Relaxation Data, Matthew Alexander Griebel Jun 2012

Viscoelastic Anisotropic Finite Element Mixture Model Of Articular Cartilage Using Viscoelastic Collagen Fibers And Validation With Stress Relaxation Data, Matthew Alexander Griebel

Master's Theses

Experimental results show that collagen fibers exhibit stress relaxation under tension and a highly anisotropic distribution. To further develop the earlier model of Stender [1], the collagen constituent was updated to reflect its intrinsic viscoelasticity and anisotropic distribution, and integrated with an existing mixture model with glycosaminoglycans and ground substance matrix. A two-term Prony series expansion of the quasi-linear viscoelastic model was chosen to model the viscoelastic properties of the collagen fibers. Material parameters were determined by using the simplex method to minimize the sum of squared errors between model results and experimental stress relaxation data of tissue in tension. …


Nano-Mechanics Of Cartilage Glycosaminoglycans Using Molecular Dynamics Methods, Kevin Neil Hendrickson Jan 2009

Nano-Mechanics Of Cartilage Glycosaminoglycans Using Molecular Dynamics Methods, Kevin Neil Hendrickson

Master's Theses

Articular Cartilage (AC) is the main load carrying material in synovial joints {Hamerman, 1962} and degeneration of AC can cause pain in the form of arthritis. Current work is centered on the method of replacing damaged cartilage inside the body (in vivo) with tissue engineered outside the body (ex vivo) {Temenoff, 2000}. In order to engineer tissue ex vivo similar to the native tissue in structure and function there must be a comprehensive understanding of the mechanical properties of AC. This work focuses on the study of glycosaminoglycans (GAGs), a molecule known to be primarily responsible for the compressive stiffness …