Organs

We use computational methods in combination with geometric models to understand the mechanical role of the topology and geometry of the mammalian brains. We find that the geometric quantifiers such as the gyrification index play a fundamental role in the overall mechanical response of the brain. 

We characterize the deformation, strain, and stretch in bulging brains using the nonlinear field theories of mechanics. We show that even small swelling volumes of 28 to 56 ml induce maximum principal strains in excess of 30%. For radially outward-pointing axons, we observe maximal normal stretches of 1.3 deep inside the bulge and maximal tangential stretches of 1.3 around the craniectomy edge.

We propose a computational model for the short-term adaptation after myocardial infarction using the continuum theory of multiplicative growth. Our model captures the effects of cell death initiating wall thinning, and collagen degradation initiating ventricular dilation. 

 Simulating the swelling in the upper layers of skin alone and the contraction of the lower layers of the skin alone, we found that neither of these mechanisms alone can be responsible for the observed wrinkled fingers. We found that the collaborative effect of both hypotheses is needed to induce wrinkles in the fingertips.