#chemist

• Autoradiographic — Relating to or concerning autoradiography or an autoradiograph; executed, detected, or documented through the use of photographic emulsions or sensors sensitive to endogenous isotopic emissions. In a structural sense, it defines laboratory techniques, analyses, images, or protocols based on the self-exposure of radioactive samples onto visual recording media, used for the precise localization of labeled molecules within cells or tissues.
• Self-sterilization — The act of self-sterilizing and its result; an autonomous physical, chemical, or biological process through which a surface, smart material, or device destroys bacteria, viruses, and other microorganisms without direct external intervention. It also refers to the automatic function of modern medical devices (such as autoclaves or incubators) to run internal total decontamination programs at the end of their operating cycle.
• Auxin — A plant hormone (phytohormone) secreted by the apical meristematic tissues of plants, possessing the fundamental property of stimulating cell elongation, root initiation, fruit development, and the orientation of plant tropisms; indole-3-acetic acid is the most common natural representative of this class.
• Auxoautotroph — An organism (especially a bacterial or fungal strain) that is capable of synthesizing by itself all the growth factors required for its metabolism (vitamins, amino acids), without needing organic supplements in the culture medium; an autotrophic organism in terms of tissue development factors.
• Auxochrome — A group of atoms (such as -OH, -NH2, -OCH3) attached to an organic molecule containing a chromophore group, whose role is to intensify, fix, or shift the color of that substance and to enable it to bond stably to textile or biological fibers.
• Avid — Desiring something with fervor, greed, or in an uncontrolled manner, being greedy for gain, honors, or knowledge; figuratively, it describes an extremely curious and passionate person, eager to absorb information, culture, or art. In chemistry and physics, the term applies to substances that exhibit a particularly high affinity for an element or compound, such as a water-avid body that rapidly absorbs moisture.
• Aviation chemistry — A specialized branch of the chemical industry and aeronautical engineering dealing with the research, synthesis, production, and testing of chemical materials used in aviation. This includes high-performance fuels, special lubricants resistant to extreme temperatures and pressures, hydraulic fluids, de-icing agents, composite resins, and protective coatings for aircraft structures.
• Avogadro — The surname of the celebrated Italian physicist and chemist Amedeo Avogadro (1776–1856), globally recognized for his fundamental contributions to the development of molecular theory. In exact sciences, his name is directly associated with 'Avogadro's number' and 'Avogadro's law', essential constants and structural principles defining the proportions between gas volume and the number of molecules contained at a given pressure and temperature.
• Axeroftol — An alternative scientific name for vitamin A1 (retinol), a fat-soluble compound essential for maintaining the structural integrity of epithelial tissues, optimizing visual processes in low-light conditions, and boosting the immune system. This organic compound acts as a cellular protective shield, preventing xerophthalmia (corneal dryness) and promoting a profound, delicate regeneration of the skin and mucous membranes.
• Azeotrope — A liquid mixture consisting of two or more chemical components that boils at a constant and fixed temperature, maintaining its identical structural composition in both the liquid and vapor phases. Because the generated vapors have exactly the same proportions of substances as the liquid from which they originate, an azeotrope cannot be separated or purified by simple fractional distillation, behaving thermodynamically like a single pure compound and requiring special separation methods, such as extractive azeotropic distillation.
• Azeotropic — Pertaining to azeotropy, regarding an azeotrope, or presenting the characteristics of a constant boiling mixture. In industrial design and thermodynamics, it describes processes, phase equilibrium phenomena, or separation methods (such as azeotropic distillation) utilized to manipulate or purify complex liquid systems whose components boil without changing their structural composition.
• Azeotropy — A remarkable physicochemical thermodynamic phenomenon characteristic of certain liquid mixtures, consisting in their property to boil at a constant and fixed temperature, generating vapors with a structural composition identical to that of the liquid phase. This phenomenon prevents the separation of components via classical fractional distillation, defining the formation of a minimum or maximum point on the vapor pressure curve and requiring the implementation of specialized separation techniques in chemical engineering.
• Azeotropism — A fundamental property of certain liquid chemical mixtures or copolymerization systems to behave as an unchanging whole during phase transitions or synthesis reactions. In polymer chemistry, azeotropism describes the structural state in which the composition of the monomer mixture remains constant throughout the reaction, giving rise to a copolymer with a perfectly uniform molecular distribution and refined mechanical properties.
• Azide — A chemical compound, a salt of hydrazoic acid, or an organic derivative containing the structural functional group consisting of three linearly bound nitrogen atoms (N3-). Inorganic azides (such as sodium azide) are highly reactive ionic substances, used in airbag systems due to their ultra-fast decomposition releasing massive amounts of nitrogen gas, whereas organic azides are crucial pillars in fine chemical synthesis and biochemistry ('click chemistry' reactions).
• Azine — A heterocyclic organic chemical compound containing one or more nitrogen atoms within a six-membered structural ring (such as pyridine); also, a generic term used to designate derivatives resulting from the condensation of hydrazine with two molecules of a carbonyl compound (aldehydes or ketones).
• Azo — Containing the azo functional group, which consists of two nitrogen atoms linked by a double bond (-N=N-), each attached to an organic hydrocarbon radical; utilized as an adjective or combining form to designate a broad class of synthetic dyes and aromatic compounds of major industrial importance.
• Azobenzene — A crystalline, orange-yellow organic chemical compound with the molecular formula C12H10N2, consisting of two benzene rings linked by an azo group (-N=N-); it is the simplest azoromatic compound and serves as a core substance in the manufacturing of azo dyes and in the study of photoisomerization.
• Azo derivative — A synthetic organic compound derived from a hydrocarbon by replacing hydrogen atoms with the azo functional group (-N=N-), directly bonded to two aromatic or aliphatic organic radicals; these compounds are intensely colored and form the basis for manufacturing most industrial dyes.
• Azoic — In organic chemistry, containing the azo functional group or relating to synthetic dyes based on this group; in geology and paleontology, completely devoid of traces of animal or plant life, a term used historically to describe geological formations prior to the appearance of the first living organisms.
• Azole — A heterocyclic organic chemical compound characterized by a five-membered aromatic ring containing at least one nitrogen atom and other heteroatoms (such as nitrogen, sulfur, or oxygen); structurally, the azole class includes foundational compounds like imidazole or triazole, extensively used in medicine as antifungal and antimicrobial agents due to their capacity to inhibit ergosterol synthesis in fungal cells.