| MRF | Markov random field; medical record file; melanocyte-[stimulating hormone]-releasing factor; mesence... |
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| NF | nafcillin; National Formulary; nephritic factor; neurofibromatosis; neurofilament; neutral fraction;... |
| RF | radial fiber; radio frequency; receptive field; regurgitant fraction; Reitland-Franklin [unit]; rela... |
| CRT | cadaveric renal transplant; cardiac resuscitation team; cathode-ray tube; certified; Certified Recor... |
| ET | educational therapy; effective temperature; ejection time; embryo transfer; endothelin; endotoxin; e... |
| Ivy bleeding time test | A bleeding time test in which a sphygmomanometer is inflated to 40 mm Hg around the upper arm, a 5-mm deep incision is made on the flexor surface of the forearm, and the time is measured to cessation of bleeding. (05 Mar 2000) |
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| thrombin time | Test of the conversion of fibrinogen to fibrin by thrombin in which clotting time of plasma mixed with a thrombin solution is measured. Time is prolonged by afibrinogenaemia, abnormal fibrinogen, or the presence of inhibitory substances, e.g., fibrin-fibrinogen degradation products, heparin. Reptilase, a thrombin-like enzyme unaffected by the presence of heparin, may be used in place of thrombin. (12 Dec 1998) |
| time | 1. Duration, considered independently of any system of measurement or any employment of terms which designate limited portions thereof. "The time wasteth [i. E. Passes away] night and day." (Chaucer) "I know of no ideas . . . That have a better claim to be accounted simple and original than those of space and time." (Reid) 2. A particular period or part of duration, whether past, present, or future; a point or portion of duration; as, the time was, or has been; the time is, or will be. "God, who at sundry times and in divers manners spake in time past unto the fathers by the prophets." (Heb. I. 1) 3. The period at which any definite event occurred, or person lived; age; period; era; as, the Spanish Armada was destroyed in the time of Queen Elizabeth; often in the plural; as, ancient times; modern times. 4. The duration of one's life; the hours and days which a person has at his disposal. "Believe me, your time is not your own; it belongs to God, to religion, to mankind." (Buckminster) 5. A proper time; a season; an opportunity. "There is . . . A time to every purpose." (Eccl. Iii. 1) "The time of figs was not yet." (Mark xi. 13) 6. Hour of travail, delivery, or parturition. "She was within one month of her time." (Clarendon) 7. Performance or occurrence of an action or event, considered with reference to repetition; addition of a number to itself; repetition; as, to double cloth four times; four times four, or sixteen. "Summers three times eight save one." (Milton) 8. The present life; existence in this world as contrasted with immortal life; definite, as contrasted with infinite, duration. "Till time and sin together cease." (Keble) 9. Tense. 10. The measured duration of sounds; measure; tempo; rate of movement; rhythmical division; as, common or triple time; the musician keeps good time. "Some few lines set unto a solemn time." (Beau. & Fl) Time is often used in the formation of compounds, mostly self-explaining; as, time-battered, time-beguiling, time-consecrated, time-consuming, time-enduring, time-killing, time-sanctioned, time-scorner, time-wasting, time-worn, etc. Absolute time, time irrespective of local standards or epochs; as, all spectators see a lunar eclipse at the same instant of absolute time. Apparent time, the time of day reckoned by the sun, or so that 12 o'clock at the place is the instant of the transit of the sun's center over the meridian. Astronomical time, mean solar time reckoned by counting the hours continuously up to twenty-four from one noon to the next. At times, at distinct intervals of duration; now and then; as, at times he reads, at other times he rides. Civil time, time as reckoned for the purposes of common life in distinct periods, as years, months, days, hours, etc, the latter, among most modern nations, being divided into two series of twelve each, and reckoned, the first series from midnight to noon, the second, from noon to midnight. Common time Apparent time as reckoned from the transit of the sun's center over the meridian. 1. To appoint the time for; to bring, begin, or perform at the proper season or time; as, he timed his appearance rightly. "There is no greater wisdom than well to time the beginnings and onsets of things." (Bacon) 2. To regulate as to time; to accompany, or agree with, in time of movement. "Who overlooked the oars, and timed the stroke." (Addison) "He was a thing of blood, whose every motion Was timed with dying cries." (Shak) 3. To ascertain or record the time, duration, or rate of; as, to time the speed of horses, or hours for workmen. 4. To measure, as in music or harmony. Origin: OE. Time, AS. Tima, akin to tid time, and to Icel. Timi, Dan. Time an hour, Sw. Timme. 58. See Tide. (01 May 1998) |
| time and motion studies | The observation and analysis of movements in a task with an emphasis on the amount of time required to perform the task. (12 Dec 1998) |
| time-compensated gain | In ultrasonography, an increase in receiver gain with time to compensate for loss in echo amplitude with depth, usually due to attenuation. Synonym: attenuation compensation, depth compensation, time compensation gain, time-compensated gain, time-varied gain control, time-varied gain. (05 Mar 2000) |
| time compensation gain | In ultrasonography, an increase in receiver gain with time to compensate for loss in echo amplitude with depth, usually due to attenuation. Synonym: attenuation compensation, depth compensation, time compensation gain, time-compensated gain, time-varied gain control, time-varied gain. (05 Mar 2000) |
| time constant | That part of a circuit that determines the time interval over which the rate of electrical events will be averaged; in pulmonary physiology, the factors determining rate of flow in the airways. (05 Mar 2000) |
| time-gain compensation | In ultrasonography, an increase in receiver gain with time to compensate for loss in echo amplitude with depth, usually due to attenuation. Synonym: attenuation compensation, depth compensation, time compensation gain, time-compensated gain, time-varied gain control, time-varied gain. (05 Mar 2000) |
| time lapse | <technique> Technique applied to speed up the action in a film or videotape sequence. In filming by taking a frame every few seconds and projecting at conventional speed (16 or 24 frames per second), the movements of cells can be greatly speeded up and then become conspicuous. With videotape, the recording is made at slow tape speed and replayed at full speed. The opposite of slow motion. (28 May 1998) |
| time-lapse microscopy | Microscopy in which the same object (e.g., a cell) is photographed at regular time intervals over several hours. (05 Mar 2000) |
| time management | Planning and control of time to improve efficiency and effectiveness. (12 Dec 1998) |
| time marker | An instrument that marks the time, usually in seconds or fractions of seconds, on a kymograph record in physiologic experiments. (05 Mar 2000) |
| time of flight | The time for a photon created by annihilation of a positron-electron pair to reach a detector; since annihilation photons are created in pairs and travel in opposite directions at about 3 × 1010 cm/sec, measurement of the difference in arrival time at detectors with sub-nanosecond resolution allows calculation of the location of the event; the basic physics of positron emission tomography. (05 Mar 2000) |
| time perception | The ability to estimate periods of time lapsed or duration of time. (12 Dec 1998) |
| time sense | The faculty by which the passage of time is appreciated. (05 Mar 2000) |