Source:http://linkedlifedata.com/resource/umls/id/C0013878
MSH: Individual components of atoms, usually subatomic; subnuclear particles are usually detected only when the atomic nucleus decays and then only transiently, as most of them are unstable, often yielding pure energy without substance, i.e., radiation.,NCI: Any of the constituent parts of an atom, including the protons, neutrons and electrons and their parts.