| ionidium | <botany> A genus of violaceous plants, chiefly found in tropical America, some species of which are used as substitutes for ipecacuanha. Origin: NL. Cf. Iodine. Source: Websters Dictionary (01 Mar 1998) |
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| ionisation | <chemistry, radiobiology> Any process by which a neutral atom gains or loses electrons, thus acquiring a net charge, as the dissociation of a substance in solution into ions or ion production by the passage of radioactive particles. High temperatures, electrical discharges or nuclear radiations can cause ionisation. (16 Dec 1997) |
| ionisation energy | <radiobiology> Generally refers to the amount of energy required to strip a particular electron from an atom. The first ionisation energy is a commonly used quantity in many fields of physics and chemistry. Typically measured in electron-volts. Equivalent to the atomic binding energy of the electron. (09 Oct 1997) |
| ionise | To separate into ions; to dissociate atoms or molecules into electrically charged atoms or radicals. (05 Mar 2000) |
| ionised atom | <chemistry> An atom that possesses an electrostatic charge as a result of loss or gain of electrons; e.g., H+, Calcium, Cl-, O2-. (05 Mar 2000) |
| ionised calcium | <biochemistry> The ionised calcium represents the calcium (Ca++) that is the metabolically active calcium. Normal values for ionised calcium in the bloodstream should be 4.4 to 5.3 mg/dl for adults and 4.4 to 6.0 mg/dl for children. Elevations may be seen in hyperparathyroidism, metastatic bone tumour, milk-alkali syndrome, multiple myeloma, Paget's disease, sarcoidosis, PTH-secreting tumours (paraneoplastic syndrome) and vitamin D intoxication. Lower than normal values may be seen in hypoparathyroidism, malabsorption, osteomalacia, pancreatitis, renal failure, rickets and vitamin D deficiency. (27 Sep 1997) |
| ionising radiation | <radiobiology> Radiation sufficiently energetic to dislodge electrons from an atom. Ionising radiation includes x and gamma radiation, electrons (beta radiation), alpha particles (helium nuclei) and heavier charge atomic nuclei. Neutrons ionise indirectly by colliding with atomic nuclei. Alpha and gamma radiation are far more effective at producing ionisation (and therefore more likely to cause tissue or cell damage) than beta radiation or neutrons. (16 Dec 1997) |
| ionium | Former term for thorium-230. Origin: G. Ion, going (05 Mar 2000) |
| ionization | <chemistry, radiobiology> Any process by which a neutral atom gains or loses electrons, thus acquiring a net charge, as the dissociation of a substance in solution into ions or ion production by the passage of radioactive particles. High temperatures, electrical discharges or nuclear radiations can cause ionisation. (16 Dec 1997) |
| ionization chamber | A chamber for detecting ionization of the enclosed gas; used for determining intensity of ionizing radiation. (05 Mar 2000) |
| ionizing radiation | Corpuscular (e.g., neutrons, electrons) or electromagnetic (e.g., gamma) radiation of sufficient energy to ionise the irradiated material. (05 Mar 2000) |
| ionogram | The result of ionography. (18 Nov 1997) |
| ionomycin | <chemical> A divalent calcium ionophore that is widely used as a tool to investigate the role of intracellular calcium in cellular processes. Pharmacological action: ionophores. Chemical name: Ionomycin (12 Dec 1998) |
| ionone | A cyclic ketone with an odour of violets or cedar wood, the a and b varieties of which differ in the location of the double bond in the ring: provitamins A and vitamin A have ionone configuration in the ring portion; alpha-carotene contains one alpha-and one beta-ionone moieties, beta-carotene contains two beta-ionone moieties, and gamma-carotene contains one beta-ionone moiety. (05 Mar 2000) |
| ionopherogram | <chemistry> The densitometric or colourimetric pattern obtained from filter paper or similar porous strips on which substances have been separated by electrophoresis; may also refer to the strips themselves. Synonym: electrophoretogram, ionogram, ionopherogram. (05 Mar 2000) |