. "More specifically R???, R??? and most particularly R?????? can be an alkyl (e.g., methyl), alkoxy (e.g., methoxy), ether (e.g., ???(CH2)kO???CH3, where k is 1, 2, 3 or 4), hydroxylamine (e.g., ???(CH2)k???NH???(CH2)l???OH, where k and l, independently, are 0, 1, 2, or 3, but are not both 0), or hydroxylamide (e.g., ???(CH2)k???CO???NH???(CH2)l???OH, where k and l, independently, are 0,1, 2, or 3," . . .