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Center for Nonlinear Studies |
We all know that cartilage is a protective tissue that coats the bone and protects it from compression and shear loads. Most investigations on the dynamic behavior of this tissue have focused on its bulk compressive properties. However, while shear stress is known to correlate with failure and disease in this tissue, the mechanisms responsible for shear energy dissipation in cartilage are poorly understood. Articular cartilage is a highly complex and heterogeneous material in its structure, composition and mechanical behavior. Understanding these spatial variations is critical to determining the mechanisms for shear energy dissipation. In this talk I will show that using a Tissue Deformation Imaging Stage in conjunction with fast confocal microscopy allows for determining the depth dependence of the shear mechanical properties of articular cartilage. Using these novel techniques we have been able to determine that nearly all of the shear energy is dissipated in a 300 micron thick region located 100 microns below the articular surface. Finally, I will comment on the relevance of this finding to diseases such as Osteoarthritis as well as some of the medical procedures that are currently being practiced.
Host: Bill Hlavacek, T-6, wish@lanl.gov