| OSF | organ system failure; osteoclast-stimulating factor; outer spiral fiber; overgrowth stimulating fact... |
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| OTF | octamer-binding transcription factor; oral transfer factor |
| PRF | partial reinforcement; patient report form; perforin; plasma recognition factor; pontine reticular f... |
| PSF | peak scatter factor; peptide supply factor; point spread function; pseudosarcomatous fasciitis |
| RIF | radiological interface; release-inhibiting factor; rifampin; right iliac fossa; rosette-inhibiting f... |
| Stuart-Prower factor | <chemical> Storage-stable glycoprotein blood coagulation factor that can be activated to factor xa by both the intrinsic and extrinsic pathways. A deficiency of factor x, sometimes called stuart-prower factor deficiency, may lead to a systemic coagulation disorder. Chemical name: Blood-coagulation factor X (12 Dec 1998) |
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| sulfation factor | <protein> Peptide hormone (4 kD) that is produced in the liver and is released in response to somatotropin. Somatomedin stimulates the growth of bone and muscle and also influences calcium, phosphate, carbohydrate and lipid metabolism. See: insulin like growth factor. (18 Nov 1997) |
| sun protection factor | A number on a scale (from 2 upwards) for rating sunscreens. Sunscreens with an spt of 15 or higher provide the best protection from the sun's harmful rays. (12 Dec 1998) |
| decapacitation factor | A factor, postulated to be present in epididymal fluid and seminal plasma, that prevents the capacitation of spermatozoa. (05 Mar 2000) |
| decay accelerating factor | <biochemistry, protein> Plasma protein that regulates complement cascade by blocking the formation of the C3bBb complex (the C3 convertase of the alternate pathway). Widely distributed in tissues but deficient in paroxysmal nocturnal haemoglobinuria. (18 Nov 1997) |
| suppressor factor | <immunology> Factors released by T suppressor cells. See: suppressor mutation, ochre suppressor, opal suppressor. (19 Jan 1998) |
| diabetogenic factor | Rarely used term for a factor in crude extracts of the anterior lobe of the hypophysis that produces degenerative changes in the islet cells of the pancreas and causes permanent diabetes. (05 Mar 2000) |
| diffusing factor | <enzyme> Enzyme that degrades hyaluronic acid, found in lysosomes. (18 Nov 1997) |
| direct lytic factor of cobra venom | A polypeptide of 62 residues; action on cells is similar to that of melittin in that it promotes disruption of membranes; used as an investigational antirheumatic agent. Synonym: cobra toxin, direct lytic factor of cobra venom. (05 Mar 2000) |
| Duran-Reynals permeability factor | <enzyme> Enzyme that degrades hyaluronic acid, found in lysosomes. (18 Nov 1997) |
| duty factor | <radiobiology> Ratio of the duration of time when a system is actually operating to the total time for a complete cycle of the system. For example: if a tokamak experiment runs for 5 seconds and then sits for 500 seconds while the power supplies are recharged, then the duty factor is 1%. Similar to capacity factor for powerplants. Synonym: duty cycle. (09 Oct 1997) |
| q-factor | <radiobiology> Ratio of power produced by fusion to power put into the reactor to heat the plasma and drive the magnetic fields. Q = 1 is the definition of scientific breakeven, where power out = power in. Economical fusion will require Q significantly greater than 1. Fortunately Q increases dramatically as the plasma parameters approach the Lawson criterion for ignition. Power to drive the magnetic fields is frequently ignored in discussions of Q, with the justification that a steady-state, continuous-output fusion reactor will have superconducting magnet coils. (15 Dec 1997) |
| quality factor | <radiobiology> (Q) A multiplying factor used with absorbed dose to convert to dose equivalent and therefore to express the radiation's effectiveness in causing biological effects. (16 Dec 1997) |
| inhibition factor | <growth factor> A soluble, nondialysable factor that is produced by sensitised lymphocytes following exposure to a specific antigen. It inhibits macrophage migration and causes adherence. It was originally defined on the basis of inhibition of emigration of mononuclear cells from capillary (haematocrit) tubes, more recently a 13 kD protein with migration inhibitory activity has been isolated. Acronym: MIF Synonym: inhibition factor. (22 Sep 2002) |
| initiation factor | One of several soluble proteins involved in the initiation of protein or RNA synthesis. (05 Mar 2000) |