Provided herein are compounds of the formulas and :as well as pharmaceutically acceptable salts thereof, wherein the substituents are as those disclosed in the specification. A drive mechanism is coupled to the second roll for translating the second roll in a first direction such that a media sheet positioned in the nip moves in the first direction towards the reference edge. , introducing gas including nitrogen atoms or mixture gas including inert gas and the gas including nitrogen atoms into a plasma process chamber, adjusting pressure in the plasma process chamber above 13. The selector system includes a slidable guide shaft that produces a linear motion linked to the drivetrain component that is proportion in magnitude and direction as that of selector lever. The process on the portable device provides data to the application on the host device using the communication link. The device facilitates the removal of tissue from the walls of the fistula allowing the introduction of collagen that aids the healing of the fistula.