2. To mitigate inflammation near implantable glucose sensors, researchers have proposed using a controlled release of dexamethasone at the implantation site. In a rat experiment, dexamethasone was dispensed from subcutaneously implanted osmotic pumps. The drug was delivered through the spherical tip ( 0.6mm radius) of a catheter connected to the pump, which kept a constant concentration in the catheter tip. The following data was recorded for the concentration profile of dexamethasone as a function of distance 6 hours after implantation. The distance is represented as the radial distance (r) from the center of the catheter tip, while the tissue concentration is indicated relative to the concentration at the tip (Cs). Create a model of the controlled release of dexamethasone from the spherical tip. 1. Draw the physical situation 2. Choose the most appropriate coordinate system 3. Defining boundary and initial conditions