Nucleic acid thermodynamics of base incompatibility by quantifying the temperature at which two strands anneal can provide information as to the similarity in base sequence between the two strands being annealed. The complexes may be dissociated by thermal denaturation, also referred to as melting. In the absence of external negative factors, the processes of hybridization and melting may be repeated in succession indefinitely, which lays the ground for polymerase chain reaction. Most commonly, the pairs of nucleic bases A=T and G≡C are formed, of which the latter is more stable. DNA denaturation, also called DNA melting, is the process by which double-stranded deoxyribonucleic
Perfluorononanoic acid Perfluorononanoic acid Perfluorononanoic acid, or PFNA, is a synthetic perfluorinated carboxylic acid and fluorosurfactant that is also an environmental contaminant found in people and wildlife along with PFOS and PFOA. In acidic form it is a highly reactive strong acid. In its conjugate base form as a salt it is stable and commonly ion paired with ammonium. In the commercial product Surflon S-111 (CAS 72968-3-88) it is the primary compound present by weight. PFNA is used as surfactant for the production of the fluoropolymer polyvinylidene fluoride. It is produced mainly in Japan by the oxidation of a linear fluorotelomer olefin