| 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) |
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| radio frequency current drive | <radiobiology> Plasma waves in the radio-frequency range can be used to push plasma particles in such a way that current forms in the plasma, this is a method of non-inductive current drive which would allow for steady-state fusion reactors to operate. (09 Oct 1997) |
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| hearing loss, high-frequency | Hearing loss in frequencies above 1000 hertz. (12 Dec 1998) |
| 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) |
| action current | An electrical current induced in muscle fibres when they are effectively stimulated; normally it is followed by contraction. (05 Mar 2000) |
| alternating current | Electrical current which alternates direction periodically. (For instance, household electric current is AC alternating at 60 oscillations/sec (60 Hertz) in the United States, and 50 Hertz in many other countries.) Acronym: AC (09 Oct 1997) |
| anodal current | A current produced in tissues under the anode when the circuit is closed. (05 Mar 2000) |
| ascending current | The direction of current flow in a nerve when the anode is placed peripheral to the cathode, in contrast to descending current; the convention used is that current flows from positive to negative. Synonym: centripetal current. (05 Mar 2000) |
| axial current | The central rapidly moving portion of the bloodstream in an artery. (05 Mar 2000) |
| bootstrap current | <radiobiology> Currents driven in toroidal devices by neo-classical diffusion. They may amount to a substantial fraction of the net current in a tokamak reactor, thus lengthening the pulse time or decreasing the power needed for current drive. (09 Oct 1997) |
| calcium current | Inflow of calcium ions through specific calcium channels. Critically important in release of transmitter substance from presynaptic terminals. (18 Nov 1997) |
| galvanic current | See: direct current, galvanism. (05 Mar 2000) |