Enrichment of  18 O in the nucleic acid bases.
D001976:Bromouracil; D004247:DNA; D007553:Isotope Labeling; D013058:Mass Spectrometry; D010103:Oxygen Isotopes; D012313:RNA; D011830:Radiation Effects; D013329:Structure-Activity Relationship; D013941:Thymine / Q000528:radiation effects; D014466:Ultraviolet Rays; D014498:Uracil / Q000528:radiation effects; D014867:Water
D010103:Oxygen Isotopes; D014867:Water; D001976:Bromouracil; D014498:Uracil; D012313:RNA; D004247:DNA; D013941:Thymine