A pneumatic tire is described having a triangular shaped apex which extends radially outward of the bead core, and wherein the apex is formed of at least two zones. The bit line sense amplifier comprises a plurality of CMOS inverters, which are cross-coupled corresponding to the paired bit lines. Rotating the shaft as the milling cutter is displaced along the surface forms a groove which can follow a variable path to follow natural obstacles when cutting across a body of ice on a natural body of water for example. The second layer is comprised of a hydrophobic heparinized polymer that inhibits blood coagulation and provides a hydrophilic surface for reducing the friction between stent and lesion site.