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A Polycyclic aromatic hydrocarbon (PAH) is a class of organic compounds that is composed of multiple aromatic rings.Most are produced by the incomplete combustion of organic matter— by engine exhaust fumes, tobacco, incinerators, in roasted meats and cereals, [1] or when biomass burns at lower temperatures as in forest fires.
Cl-PAHs with three to five rings have been reported to occur in air from road tunnels, sediment, snow, and kraft pulp mills. [8] Recently, the occurrence of particulate Cl-PAHs has been investigated. Results have shown that most particulate Cl-PAH concentration detected in urban air tended to be high in colder seasons and low in warmer seasons.
PAH world hypothesis, hypothesis that proposes that the use of polycyclic aromatic hydrocarbons was a means for the origin of life; Polyallylamine hydrochloride, a polyelectrolyte used in polymer sheets; Polyanhydrides, a class of biodegradable polymers; Photoacid, where H indicates an H atom lost by an acid
Pulmonary Arterial Hypertension (PAH) is a syndrome in which the blood pressure in the pulmonary arteries and pulmonary arterioles (the blood vessels located proximal to the capillary bed, the site of oxygen exchange in the lungs) is elevated.
The PAH world hypothesis is a speculative hypothesis that proposes that polycyclic aromatic hydrocarbons (PAHs), known to be abundant in the universe, [1] [2] [3] including in comets, [4] and assumed to be abundant in the primordial soup of the early Earth, played a major role in the origin of life by mediating the synthesis of RNA molecules, leading into the RNA world.
Para-aminohippurate (PAH) clearance is a method used in renal physiology to measure renal plasma flow, which is a measure of renal function. [citation needed]PAH is completely removed from blood that passes through the kidneys (PAH undergoes both glomerular filtration and tubular secretion), and therefore the rate at which the kidneys can clear PAH from the blood reflects total renal plasma flow.
Aminohippuric acid or para-aminohippuric acid (PAH), a derivative of hippuric acid, is a diagnostic agent useful in medical tests involving the kidney used in the measurement of renal plasma flow. It is an amide derivative of the amino acid glycine and para -aminobenzoic acid that is not naturally found in humans; it needs to be IV infused ...
Phenylalanine hydroxylase (PAH) (EC 1.14.16.1) is an enzyme that catalyzes the hydroxylation of the aromatic side-chain of phenylalanine to generate tyrosine.PAH is one of three members of the biopterin-dependent aromatic amino acid hydroxylases, a class of monooxygenase that uses tetrahydrobiopterin (BH 4, a pteridine cofactor) and a non-heme iron for catalysis.