| forced cycle | <cardiology, physiology> A cardiac cycle (atrial or ventricular) that is cut short by a forced beat. (05 Mar 2000) |
|---|---|
| fuel cycle | The series of steps required to produce electricity. The fuel cycle includes mining or otherwise acquiring the raw fuel source, processing and cleaning the fuel, transport, electricity generation, waste management and plant decommissioning. (05 Dec 1998) |
| futile cycle | <biochemistry> Any seqence of enzyme catalysed reactions in which the forward and reverse processes (catalysed by different enzymes) are consititutively active. Frequently used to describe the cycle of phosphorylation and dephosphorylation of phosphatidyl inositol derivatives in cell membranes. (05 Jan 1998) |
| levelised life-cycle cost | The present value of the cost of a resource, including capital, financing and operating costs, expressed as a stream of equal annual payments. This stream of payments can be converted to a unit cost of energy by dividing the annual payment amount by the annual kilowatt-hours produced or saved. By levelizing costs, resources with different lifetimes and generating capabilities can be compared. (05 Dec 1998) |
| life cycle | The entire life history of a living organism. (05 Mar 2000) |
| life-cycle costing | A method of comparing costs of equipment or buildings based on original costs plus all operating and maintenance costs over the useful life of the equipment. Future costs are discounted. (05 Dec 1998) |
| life cycle stages | The continuous sequence of changes undergone by metamorphosing insects and other animals during the developmental process. (12 Dec 1998) |
| lytic cycle | The general life cycle of a lytic virus, from infection of the host cell, hijacking of the host cells mechanisms, use of the host cells mechanisms to produce viral components, and assembly of the components into progeny viruses, to the destruction of the host cell by rupturing its plasma membrane (lysis) and the release of the progeny viruses so that they can spread and infect other cells. (09 Oct 1997) |
| absent nasal septum | <radiology> Cocaine, Wegener's (midline lethal granuloma), surgery, trauma, syphilis, sarcoid (12 Dec 1998) |
| accessory nasal cartilages | Variable small plates of cartilage located in the interval between the greater alar and lateral nasal cartilages. Synonym: cartilagines nasales accessoriae, sesamoid cartilages of nose. (05 Mar 2000) |
| anterior nasal aperture | The anterior nasal opening in the skull. Synonym: apertura piriformis, piriform opening. (05 Mar 2000) |
| anterior nasal spine | A pointed projection at the anterior extremity of the intermaxillary suture; the tip, as seen on a lateral cephalometric radiograph, is used as a cephalometric landmark. Synonym: spina nasalis anterior. (05 Mar 2000) |
| benign nasal tumour | A benign tumour of the posterior nasopharynx that is most common in adolescent boys. Symptoms repeated epistaxis, nasal congestion, nasal discharge and hearing loss. A skull X-ray or a CT scan of the head can confirm the presence of an angiofibroma. Treatment may include the surgical removal of the lesion if it is enlarging or blocking the airway. (27 Sep 1997) |
| bony nasal septum | The bones supporting the bony part of the nasal septum; these are the perpendicular plate of the ethmoid, the vomer, the sphenoidal rostrum, the crest of the nasal bones, the frontal spine, and the median crest formed by the apposition of the maxillary and palatine bones. Synonym: septum nasi osseum. (05 Mar 2000) |
| bony part of nasal septum | The major portion of the nasal septum supported by the vomer and the perpendicular plate of the ethmoid. Synonym: pars ossea septi nasi. (05 Mar 2000) |