| absorption | The process of absorbing, specifically: 1. <physiology> The movement and uptake of substances (liquids and solutes) into cells or across tissues such as skin, intestine and kiidney tubules, by way of diffusion or osmosis. 2. <chemistry> The drawing of a gas or liquid into the pores of a permeable solid. 3. <psychology> The devotion of thought to one object or activity, with inattention to others. 4. <radiology> The taking up of energy by matter with which the radiation interacts. 5. <physics> The loss of (electromagnetic) energy to a medium. For instance, an electromagnetic wave which propagates through a plasma will set the electrons into motion. If the electrons make collisions with other particles, they will absorb net energy from the wave. 6. <immunology> A process in which an antigen or antibody is used to pull an analogous antigen or antibody out of a solution. Compare: adsorption. Origin: L. Absorptio (12 Nov 1997) |
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| absorption band | The range of wavelengths or frequencies in the electromagnetic spectrum where radiant energy is absorbed by passage through a gaseous, liquid, or dissolved substance; it is exploited for analytical purposes in colourimetry or spectrophotometry, and is usually described in terms of the wavelength where maximum absorbance occurs (i.e., lambdamax). (05 Mar 2000) |
| absorption cell | A small glass chamber with parallel sides, in which absorption spectra of solutions can be obtained. (05 Mar 2000) |
| absorption chromatography | <investigation> Techniques for separating molecules based on differential absorption and elution. Term for separation methods involving flow of a fluid carrier over a nonmobile absorbing phase. (18 Nov 1997) |
| absorption coefficient | <physics> Measures the degree of wave absorption defined as the fraction of wave energy lost as the wave travels a unit distance. See: absorption. (15 Jan 1998) |
| absorption collapse | Pulmonary collapse due to rapid complete obstruction of a large bronchus. (05 Mar 2000) |
| absorption fever | An elevation of temperature often occurring, without other untoward symptoms, shortly after childbirth, assumed to be due to absorption of uterine discharges through abrasions of the vaginal wall. (05 Mar 2000) |
| absorption lines | The dark line's in the solar spectrum due to absorption by the solar and the earth's atmosphere; the phenomenon occurs because rays passing from an incandescent body through a colder medium are absorbed by elements in that medium. (05 Mar 2000) |
| absorption spectroscopy | <investigation> This is the use of a spectrophotometer to measure the ability of particles (solutes) in a solution to absorb light through a range of specific wavelengths. Every compound absorbs light differently, so absorption spectra can be used to identify compounds, measure concentrations, and determine reaction rates. (15 Jan 1998) |
| absorption spectrum | <chemistry> A graph of the amount of light a substance absorbs, plotted as a fuction of energy, frequency or wavelength. (15 Jan 1998) |
| atomic absorption spectrophotometry | Determination of concentration by the ability of atoms to absorb radiant energy of specific wavelengths. (05 Mar 2000) |
| parenteral absorption | Absorption by any route other than the alimentary tract. (05 Mar 2000) |
| mass energy absorption coefficient | <physics> The mass energy absorption coefficient, uen/p of a material for uncharged ionising particles is the product of the mass energy transfer coefficient, utr/p and (1 - g) where g is the fraction of the energy of secondary charged particles that is lost to bremsstrahlung in the material. (16 Dec 1997) |
| pathologic absorption | Parenteral absorption of any excremental or pathologic material into the bloodstream, e.g., pus, urine, bile, etc. (05 Mar 2000) |
| vitamin B12 absorption test | <investigation> This test measures the amount of vitamin B12 in the urine after ingesting a dose of B12. This test evaluates vitamin B12 absorption. The cells in the stomach produce a substance known as intrinsic factor. This substance combines with B12 to allow absorption in the distal ileum. The patient is given a small dose of radioactive B12 which can then be detected in the patients urine. Pernicious anaemia is the clinical result of B12 deficiency. Conditions that can result in an abnormal Schilling test include: deficiency of intrinsic factor, malabsorption or the development of an antibody to intrinsic factor. The Schilling test can be performed with or without administration of intrinsic factor to determine what the underlying cause for pernicious anaemia. Laxative use, renal insufficiency and hypothyroidism can all interfere with the results of this test. (27 Sep 1997) |