A heel cup formed from a flexible material is located under the heel region of an upper portion of an article of footwear. Isolated saline delivery washes cells from a urethra that are collected for cancer diagnosis. An insulating sleeve is disposed between the output shaft and rotor core, forming a capacitor between the output shaft and rotor core, thereby reducing the EMI caused by the fluctuating current in the winding coils. The dry substrate may be selected from facial tissue, bath tissue, paper towel, or dinner napkin.