Physical Sciences and Mathematics Commons^™

Unique Role Of Vimentin Networks In Compression Stiffening Of Cells And Protection Of Nuclei From Compressive Stress, Katarzyna Pogoda, Fitzroy Byfield, Piotr Deptuła, Mateusz Cieśluk, Łukasz Suprewicz, Karol Skłodowski, Jordan L. Shivers, Anne Van Oosten, Katrina Cruz, Ekaterina Tarasovetc, Ekaterina L. Grishchuk, Fred C. Mackintosh, Robert Bucki, Alison E. Patteson, Paul A. Janmey

Physics - All Scholarship

In this work, we investigate whether stiffening in compression is a feature of single cells and whether the intracellular polymer networks that comprise the cytoskeleton (all of which stiffen with increasing shear strain) stiffen or soften when subjected to compressive strains. We find that individual cells, such as fibroblasts, stiffen at physiologically relevant compressive strains, but genetic ablation of vimentin diminishes this effect. Further, we show that unlike networks of purified F-actin or microtubules, which soften in compression, vimentin intermediate filament networks stiffen in both compression and extension, and we present a theoretical model to explain this response based on …

Design, Fabrication, And Characterization Of An Array Of Graphene Based Variable Capacitors, Millicent Nkirote Gikunda

Graduate Theses and Dissertations

Since it was first isolated and characterized in 2004, graphene has shown the potential for a technological revolution. This is due to its amazing physical properties such as high electrical conductivity, high thermal conductivity, and extreme flexibility. Freestanding graphene membranes naturally possesses an intrinsic rippled structure, and these ripples are in constant random motion even room temperatures. Occasionally, the ripples undergo spontaneous buckling (change of curvature from concave to convex and vice versa) and the potential energy associated with this is a double well potential. This movement of graphene is a potential source of vibrational energy.

In this dissertation, we …