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Full-Text Articles in Engineering
Effect Of Stress State On Wrinkle Morphology, Derek Breid, Alfred Crosby
Effect Of Stress State On Wrinkle Morphology, Derek Breid, Alfred Crosby
Alfred Crosby
Wrinkles in thin films on soft substrates have been shown to self-organize into topological patterns, providing a possible route towards inexpensive generation of surface microstructure. However, the effect of the magnitude of applied stress in relation to the critical buckling stress, or overstress, on the observed patterns has until this point been neglected experimentally. In this paper, we investigate the effect of overstress using poly(dimethylsiloxane) which has been surface-oxidized with a UV-ozone oxidation technique. Using a swelling-based stress application technique, where the applied swelling stress in the thin film is controlled by changing the concentration of vapor-phase swelling agent (ethanol) …
Blowing Bubbles To Study Living Material, Alfred Crosby, Jennifer J. Mcmanus
Blowing Bubbles To Study Living Material, Alfred Crosby, Jennifer J. Mcmanus
Alfred Crosby
Living materials respond to stresses, or deformation forces, in profound and surprising ways. Bones become weak if they don’t carry weight. Muscles and soft tissues atrophy, or shrink, if exercise is limited. Whether stem cells differentiate into hard or soft tissue can strongly depend on the stresses they experience during growth. Therefore, to promote or direct the growth of healthy tissue—the challenge of tissue engineering—or to limit the growth of unwanted tissue such as cancerous tumors, scientists must understand the stresses that biological materials experience as they grow and live.
Cavitation Rheology Of The Eye Lens, Alfred Crosby, Jun Cui, Cheol Hee Lee, Aline Delbos, Jennifer J. Mcmanus
Cavitation Rheology Of The Eye Lens, Alfred Crosby, Jun Cui, Cheol Hee Lee, Aline Delbos, Jennifer J. Mcmanus
Alfred Crosby
The anisotropic mechanical properties of bovine eye lenses were measured using cavitation rheology over a range of length scales. The technique involves inducing a cavity at the tip of a syringe needle in different regions of the lens. Effective Young's moduli of the nucleus and cortex of the lens were determined, as approximately 11.8 and 0.8 kPa, respectively, on macroscopic length scales. We also measured the mechanical properties of the lens on the length scale of a single cell, suggesting that the stiffness significantly decreased from that in the bulk measurements for both the nucleus and cortex. In addition, during …