| adsorption | 1. <chemistry> The accumulation or concentration of molecules of a gas or liquid on a surface in contact with the gas or liquid, resulting in a relatively high concentration of the gas or solution at the surface. Note that the accumulating molecules do not actually penetrate the substance they are on. Compare: absorption. 2. <virology> The adhesion of a substance to an organic particle in a solution, for example the adhesion of a virus to a cell. Origin: L. Sorbere = to suck (10 May 1997) |
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| adsorption chromatography | Chromatography in which separation of substances is achieved by the difference in degree of adsorption of the compounds to a stationary phase. (05 Mar 2000) |
| adsorption fermentation | <microbiology> (extractive fermentation) A fermentation technique in which products of the fermentation are removed from the broth by adsorption onto materials such as carbon or polymers. Generally, the preferred method of doing this is to circulate the fermenting broth through the adsorbent substrate, because the fermentation products are often toxic to the microbes. (06 May 1997) |
| adsorption theory of narcosis | That a drug becomes concentrated at the surface of the cell as a result of adsorption, and thus alters permeability and metabolism. (05 Mar 2000) |
| immune adsorption | Removal of antibody (agglutinin or precipitin) from antiserum by use of specific antigen; after aggregation has occurred, the antigen-antibody complex is separated either by centrifugation or by filtration, removal of antigen by specific antiserum in a similar manner. (05 Mar 2000) |
| bone scan: falsely negative metastases | <radiology> Anaplastic tumours, reticulum cell sarcoma, renal cell carcinoma, thyroid carcinoma, histiocytosis, neuroblastoma, multiple myeloma (positive scan usually due to recent or impending fracture) (12 Dec 1998) |
| ventilators, negative-pressure | Body ventilators that assist ventilation by applying intermittent subatmospheric pressure around the thorax, abdomen, or airway and periodically expand the chest wall and inflate the lungs. They are relatively simple to operate and do not require tracheostomy. These devices include the tank ventilators ("iron lung"), portalung, pneumowrap, and chest cuirass ("tortoise shell"). (12 Dec 1998) |
| gram-negative | <microbiology> A common class of bacteria normally found in the gastrointestinal tract that can be responsible for disease in man (sepsis). Bacteria are considered to be gram-negative because of their characteristic staining properties under the microscope, where they either do not stain or are decolourised by alcohol during Gram's method of staining. This is a primary characteristic of bacteria that have a cell wall composed of a thin layer of peptidoglycan covered by an outer membrane of lipoprotein and lipopolysaccharide containing endotoxin. The gram staining characteristics of bacteria have resulted in an important classification system for the identification of bacteria. See: gram-positive (06 Oct 1997) |
| gram-negative aerobic bacteria | <microbiology> A large group of aerobic bacteria which show up as pink (negative) when treated by the gram-staining method. (12 Dec 1998) |
| gram-negative aerobic rods and cocci | <microbiology> A group of gram-negative bacteria consisting of rod- and coccus-shaped cells. They are both aerobic (able to grow under an air atmosphere) and microaerophilic (grow better in low concentrations of oxygen) under nitrogen-fixing conditions but, when supplied with a source of fixed nitrogen, they grow as aerobes. (12 Dec 1998) |
| gram-negative anaerobic bacteria | <microbiology> A large group of anaerobic bacteria which show up as pink (negative) when treated by the gram-staining method. (12 Dec 1998) |
| gram-negative anaerobic cocci | <microbiology> A group of anaerobic coccoid bacteria that show up as pink (negative) when treated by the gram-staining method. (12 Dec 1998) |
| gram-negative anaerobic straight, curved, and helical rods | <microbiology> A group of anaerobic, rod-shaped bacteria that show up as pink (negative) when treated by the gram-staining method. (12 Dec 1998) |
| gram-negative bacteria | <microbiology> Bacteria which lose crystal violet stain but are stained pink when treated by gram's method. (12 Dec 1998) |
| gram-negative bacterial infections | <microbiology> Infections caused by bacteria that show up as pink (negative) when treated by the gram-staining method. (12 Dec 1998) |