Embodiments provide a DC-DC converter for envelope tracking. In one embodiment, the present invention provides a method of degrading succinoglycan comprising contacting the succinoglycan with an enzyme composition that comprises enzymes that are capable of degrading the linkages between sugar moieties of the succinoglycan. The pressure-side tip wall includes a continuously concave curved arcuate portion, at least a section of which extends circumferentially outward from a radial axis of the airfoil. In other embodiments, the invention includes a method to descramble a bit scrambled video signal in a computer.