A reciprocating internal combustion engine. A record and its associated key value are read from each of the files. The compounds can further include a brush-like portion, capable of creating a steric barrier between a damaged tissue or organ and adjacent tissues or organs, and a targeting portion, capable of directing the compounds to a damaged tissue or organ. The invention further offers methods of instrumentation to detect unwanted reflections, to compensate, and to correct for the distortions caused by reflections.