WEST LAFAYETTE, Ind. — Diabetes can lead to ulcers that patients don’t even feel or notice until the sight of blood. And because ulcers can’t heal on their own, 14 to 24 percent of diabetics in the U.S. who experience them end up losing their toes, foot or leg. Purdue University researchers have developed a shoe insole that could help make the healing process more portable for the 15 percent of Americans who develop ulcers as a result of diabetes....