| form | 1. <zoology> An infrasubspecific category which has no status in the classification code. 2. <suffix> In the form, shape of, mold; equivalent to -oid. See: morpho-. Origin: L. -formis, L. Forma (20 Jun 2000) |
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| form perception | The sensory discrimination of a pattern shape or outline. (12 Dec 1998) |
| Formad's kidney | <nephrology> An enlarged and deformed kidney sometimes seen in chronic alcoholism. (05 Mar 2000) |
| Formad, Henry | <person> U.S. Physician, 1847-1892. See: Formad's kidney. (05 Mar 2000) |
| formal operations | <psychology> In the psychology of Piaget, a stage of development in thinking, occurring approximately between 11 and 15 years of age, during which a child becomes capable of reasoning about abstract situations; reasoning at this stage is comparable to that of normal adults but less sophisticated. (05 Mar 2000) |
| formaldehyde | <chemical> Commonly used fixative and antibacterial agent. As a fixative it is cheap and tends to cause less denaturation of proteins than does glutaraldehyde, particularly if used in a well buffered solution (buffered formalin, formal saline). Old formaldehyde solutions usually contain cross linking contaminants and it is therefore often preferable to used a formaldehyde generating agent such as paraformaldehyde. Formalin fumes, particularly in conjunction with hydrochloric acid vapour, are potently carcinogenic. (20 Jun 2000) |
| formaldehyde dismutase | <enzyme> Contains noncovalently bound nad(h); forms equimolar amounts of corresponding alcohols and acids from various aldehydes Registry number: EC 1.1.1.- (26 Jun 1999) |
| formaldehyde ferredoxin oxidoreductase | <enzyme> Contains molybdopterin as the organic component of tungsten cofactor Registry number: EC 1.2.7.- Synonym: hcho ferredoxin oxidoreductase (26 Jun 1999) |
| formaldehyde fixative | A widely used fixing agent for pathologic histology; the commercial solution is 37-40% formaldehyde and is known as 100% formalin or formol; a common impurity is formic acid, which must be neutralised or the fixative made in buffer solution; tissues fixed may have a pigment artifact precipitated. (05 Mar 2000) |
| formaldehyde reductase | <enzyme> Catalyses reduction of formaldehyde to methanol using NADH Registry number: EC 1.1.1.- (26 Jun 1999) |
| formaldehyde transketolase | <enzyme> From yeast; formaldehyde plus xylulose-5-phosphate yields glyceraldehydephosphate and dihydroxyacetone Registry number: EC 2.2.1.3 Synonym: dihydroxyacetone synthase (26 Jun 1999) |
| formalin | A 37% aqueous solution of formaldehyde. Synonym: formol. (05 Mar 2000) |
| formalin pigment | <chemistry> A pigment formed when acid aqueous solutions of formaldehyde act on blood-rich tissues; characterised by rotation of the plane of polarised light, withstanding extraction in aqueous and lipid solvents, being bleached in acids and hydrogen peroxide; not formed when tissue is fixed with formaldehyde buffered to pH levels above 6. (05 Mar 2000) |
| formalinise | <procedure> To add formalin solution to inactivate vaccines without destroying their immunizing power. (05 Mar 2000) |
| formamidase | <enzyme> Isolated from methylophilus methylotrophus; genbank x99632 Registry number: EC 3.5.1.49 Synonym: fmda gene product (26 Jun 1999) |
| a-form DNA | <molecular biology> One of several forms that can be assumed by a double helix. A-DNA is stable in dehydrated conditions. This form is less common than the dominant form found under physiological conditions -- beta-DNA. This form is also assumed by DNA-RNA hybrid helices and by regions of double-stranded RNA. It is a right-handed helix and is a more compact form than beta-DNA. (09 Oct 1997) |
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| boat form | The less stable of two conformations assumed by 6-membered cyclic sugars (pyranoses) or cyclohexane derivatives, as opposed to chair form. See: Haworth conformational formulas of cyclic sugars. (05 Mar 2000) |
| cavity preparation form | The configuration or shape of a cavity preparation. (05 Mar 2000) |
| replicative form | An intermediate stage in the replication of either DNA or RNA viral genomes that is usually double stranded, the altered, double-stranded form to which single-stranded coliphage DNA is converted after infection of a susceptible bacterium, formation of the complementary ("minus") strand being mediated by enzymes that were present in the bacterium before entrance of the viral ("plus") strand. (05 Mar 2000) |
| resistance form | The shape given to a cavity preparation that enables the dental restoration to withstand masticatory forces. (05 Mar 2000) |
| retention form | The shape of a cavity preparation that prevents displacement of the dental restoration by lateral or tipping forces as well as masticatory forces. (05 Mar 2000) |
| chair form | The more stable of two conformations assumed by 6-membered cyclic sugars (e.g., the pyranoses) or cyclohexane derivatives, as opposed to boat form. See: Haworth conformational formulas of cyclic sugars. (05 Mar 2000) |
| wave form | The form of a pulse; e.g., an arterial pressure or displacement wave; or of the pacemaker pulse as demonstrated on the oscilloscope under a specified load. Synonym: waveshape. (05 Mar 2000) |
| wax form | A pattern of wax that, when invested and burned out or otherwise eliminated, will produce a mold in which a casting may be made. Synonym: wax form. (05 Mar 2000) |
| convenience form | The changes needed outside the basic outline form to enable proper instrumentation for the cavity preparation and insertion of a dental restoration. (05 Mar 2000) |
| myocardial infarction in dumbbell form | Infarction involving the septum along with both inferior and anterior walls to make an H-or dumbbell-shaped configuration. Synonym: Roesler-Bressler infarct. (05 Mar 2000) |
| posterior tooth form | The distinguishing contours of the occlusal surface of the various posterior teeth. (05 Mar 2000) |
| half-chair form | See: Haworth conformational formulas of cyclic sugars. (05 Mar 2000) |
| sickle form | The male or female gametocyte(s) of Plasmodium falciparum, whose presence in human red blood cells is diagnostic of falciparum malaria. Synonym: crescent, sickle form. Myopic crescent, a white or grayish white crescentic area in the fundus of the eye located on the temporal side of the optic disk; caused by atrophy of the choroid, permitting the sclera to become visible. Synonym: myopic conus. Sublingual crescent, the crescent-shaped area on the floor of the mouth formed by the lingual wall of the mandible and the adjacent part of the floor of the mouth. (05 Mar 2000) |
| skew form | See: Haworth conformational formulas of cyclic sugars. (05 Mar 2000) |