| B1 | induced field in magnetic resonance imaging; radiofrequency magnetic field in nuclear magnetic reson... |
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| EF | ectopic focus; edema factor; ejection fraction; elastic fibril; electric field; elongation factor; e... |
| FA | false aneurysm; Families Anonymous; Fanconi anemia; far advanced; fatty acid; febrile antigen; femor... |
| FF | degree of fineness of abrasive particles; fat-free; father factor; fecal frequency; fertility factor... |
| FFF | degree of fineness of abrasive particles; field-flow fractionation; flicker fusion frequency |
| plasma frequency | <radiobiology> The natural collective oscillation frequency of a charge species (electrons, ions, etc.) in a plasma, in the absence of (or at least parallel to) a magnetic field. Also known as Langmuir or Langmuir-Tonks frequency. See: electrostatic waves, plasma oscillations. (09 Oct 1997) |
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| mutational frequency | The proportions of mutations in a population. (05 Mar 2000) |
| critical flicker fusion frequency | The minimal number of flashes of light per second at which an intermittent light stimulus no longer stimulates a continuous visual sensation. (05 Mar 2000) |
| cyclotron frequency | <radiobiology> Number of times per second that a particle orbits a magnetic field line. The frequency is completely determined by the strength of the field and the particle's charge-to-mass ratio. (Often, and incorrectly, called the Larmor frequency. The cyclotron or gyrofrequency is twice the Larmor frequency of precession.) (09 Oct 1997) |
| hearing loss, high-frequency | Hearing loss in frequencies above 1000 hertz. (12 Dec 1998) |
| high frequency current | An alternating electric current having a frequency of 10,000 or more per second; it produces no muscular contractions and does not affect the sensory nerves. Synonym: d'Arsonval current, Tesla current. (05 Mar 2000) |
| high frequency deafness | Selective loss of hearing acuity for high frequencies, usually associated with neurosensory damage; common in acoustic trauma. (05 Mar 2000) |
| high-frequency jet ventilation | Respiratory support system used primarily with rates of about 100 to 200/min with volumes of from about one to three times predicted anatomic dead space. Used to treat respiratory failure and maintain ventilation under severe circumstances. (12 Dec 1998) |
| high frequency recombination strain | A type of bacterial strain which is able to pass on genetic information to neighboring bacteria at a high rate. The high-frequency recombination strain (Hfr) is able to do this because it possesses the f plasmid and can therefore initiate bacterial conjugation. (09 Oct 1997) |
| high frequency transduction | Specialised transduction in which the donor bacterium contains not only the transducing, defective probacteriophage but also nondefective prophage that serves as "helper" virus, enabling most of the defective prophage particles to develop sufficiently to function as transducing agents. (05 Mar 2000) |
| high-frequency ventilation | Ventilatory support system using frequencies from 60-900 cycles/min or more. Three types of systems have been distinguished on the basis of rates, volumes, and the system used. They are high frequency positive-pressure ventilation (hfppv), high-frequency jet ventilation (hfjv), and high-frequency oscillation (hfo). (12 Dec 1998) |
| nearest neighbor frequency | The frequency by which certain types of entities or structures are immediately adjacent to a given structure. (05 Mar 2000) |
| dominant frequency | The frequency occurring most often in an electroencephalogram. (05 Mar 2000) |
| flicker fusion frequency technique | A technique of perimetry using the criterion of critical fusion frequency. Synonym: flicker fusion frequency technique. (05 Mar 2000) |
| Larmor frequency | In magnetic resonance, the precessional frequency, n0, of magnetic nuclei in a plane perpendicular to the direction of the external magnetic field; v0 = gB0/2π, where B0 is the magnetic field strength and g is the magnetogyric ratio. (05 Mar 2000) |