Disclosed is a method of down-regulating the expression of a gene in an animal, wherein a pharmacological formulation comprising a chimeric oligonucleotide complementary to the gene is orally administered to an animal. At least one of the blades has at least one cutout. A context model provides an objective frame of reference in which to compare one or more of the plurality of potentially applicable paraphrase alternation patterns to the textual input to determine whether the pattern can be applied without changing meaning.