An inflatable cushion useable for an ice cream maker. The distance-measuring system also includes reference optics for guiding light emitted by the light source within the system towards the light detector as internal reference light and a variable attenuator for adjusting intensity of light incident on the light detector. The unlocked position is a function of the presence of a matching key in the keyway. The encoding includes, for respective source frames, converting respective pluralities of pulse-code modulated audio samples to respective pluralities of floating-point frequency samples that are divided into a plurality of frequency bands. The at least one sinker contact is proximate sidewalls of at least a portion of the trench and is adjacent the buried layer. The compounds, compositions, and methods provided are useful for the treatment of virus infections, particularly hepatitis C infections.