Data: 9 de janeiro
Hora: 15h30
Local: Sala de Reuniões do Pavilhão Central, Campus Alameda e Online
Moderadora: Prof. Ana Paula Serro (Departamento de Engenharia Química do Instituto Superior Técnico)

«Markus A. Wimmer será o orador da IST Distinguished Lecture, intitulada “Articular Cartilage Shear and Tensile Properties in the Context of Tissue Wear”. Realiza-se no âmbito da parceria entre o Instituto Superior Técnico e a Embaixada dos Estados Unidos da América relativa ao programa “American Corners Portugal”.

Resumo:
Historically, osteoarthritis (OA) has been considered a disease of ‘cartilage wear and tear’. It is now well-established that OA is not simply a disease of tissue wear, but a multifactorial problem involving biological and mechanical mechanisms. Yet, knowledge of how OA leads to loss of mechanical tissue competence will provide additional perspective in the understanding of disease progression. The objective of the present study was to use oscillatory sinusoidal shear to further investigate tissue behavior under various compressive strains. Since the disruption of the collagen network of the superficial zone is observed as a major event in early osteoarthritis, we studied intact cartilage samples and damaged samples with removed superficial zone. We first hypothesized that compressive strain affects shear behavior protecting the tissue from micro-damage, and that the superficial zone plays a significant role in the protection of cartilage against tissue damage. Second, we were interested in the depth-dependent tensile properties of the tissue, since tensile stress can lead to rupture of collagen fibers. While work has been performed to capture tensile properties, a thorough depth dependent analysis has not been done, primarily due to constraints in sample geometry. Here, we decreased the thickness of cartilage samples and thus increased the spatial resolution to include all zones of cartilage.

Biografia do orador:
Professor Wimmer is the Grainger Director of the Rush Arthritis and Orthopedics Institute in Chicago (USA) and serves as the Associate Chairman for Research in the Department of Orthopedic Surgery at Rush University Medical Center. He also holds appointments in the Departments of Cell and Molecular Medicine and Rheumatology, as well as Bioengineering at the University of Illinois.
Prof. Wimmer received his Diploma in Mechanical Engineering from the Technical University of Munich (Germany). After a post-graduate year in Chicago, Prof. Wimmer continued his education in Germany and earned a doctorate in Biomechanics at the Hamburg University of Technology. Before joining Rush in 2001, he spent four years at the AO Research Institute in Davos, Switzerland.
Prof. Wimmer’s current research focuses on the phenomena between interacting surfaces of natural and artificial joints. He has published over one hundred-sixty peer-reviewed manuscripts.»