Dr. broncho used an afm system with a spherical indenter tip (diameter 0.8 um) to probe the stiffness of the cultured mesenchymal stem cells. he measured a cell indentation of 0.08 jum under the quasi-static load of 80 pn. assume the poisson's ratio for these cells are 0.45 (a) estimate the young's modulus of these stem cells. (b) dr. broncho then treated these cells with cytochalasin d and did the similar afm test again, he found that only 28-pn load was needed to cause 0.08 am indentation on the treated cells. dr. broncho determine the young's modulus of the treated cells. briefly describe why this result is quite different compared with the value for untreated cells. (c) if dr. broncho wants these cells to become osteoblast-like cells after culture, what would be the magnitude of the elasticity of the substrate he needs to use? why?