| linear energy transfer | <radiobiology> Average amount of energy lost per unit of particle track length and expressed in keV um-1. Acronym: LET (16 Dec 1997) |
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| linear epidermal nevus | A congenital systematised linear nevus limited to one side of the body or to portions of the extremities on one side; lesions are often extensive, forming wave-like bands on the trunk and spiraling streaks on the extremities. Synonym: linear epidermal nevus. (05 Mar 2000) |
| linear fracture | A fracture running parallel with the long axis of the bone. Synonym: fissured fracture. (05 Mar 2000) |
| linear IgA bullous disease in children | A rare self-limiting bullous disease, chiefly of the trunk, perioral, and pelvic areas, with onset in the first decade, successively less severe recurrences, and total remission at adolescence; linear epidermal basement membrane zone deposit of IgA is found in involved and in normal skin. Synonym: linear IgA bullous disease in children. (05 Mar 2000) |
| linear models | Statistical models in which the value of a parameter for a given value of a factor is assumed to be equal to a + bx, where a and b are constants. The models predict a linear regression. (12 Dec 1998) |
| linear skull fracture | A skull fracture resembling a line. (05 Mar 2000) |
| anterior focal point | The point where parallel rays from the retina are focused. (05 Mar 2000) |
| back focal length | <microscopy> As measured on the principal axis, from the second lens vertex to the back focal point of the lens. It is not the equivalent of the focal length. (05 Aug 1998) |
| back focal plane | <microscopy> The plane, normal to the lens axis, situated at the back focus of a lens. (05 Aug 1998) |
| Berger's focal glomerulonephritis | Glomerulonephritis affecting a small proportion of renal glomeruli which commonly presents with haematuria and may be associated with acute upper respiratory infection in young males, not usually due to streptococci; associated with IgA deposits in the glomerular mesangium and may also be associated with systemic disease, as in Henoch-Schonlein purpura. Synonym: Berger's disease, Berger's focal glomerulonephritis, focal nephritis, IgA nephropathy. (05 Mar 2000) |
| glomerulosclerosis, focal | Glomerular disease characterised by focal and segmental areas of glomerular sclerosis, usually commencing in the juxtamedullary glomeruli and gradually spreading to involve other parts of the kidney, with eventual kidney failure. (12 Dec 1998) |
| chronic focal sclerosing osteomyelitis | A reaction of bone to a mild bacterial infection, often the result of a carious tooth, in persons with a high degree of tissue resistance; results in a localised radio-opacity. Synonym: focal condensing osteitis. (05 Mar 2000) |
| plane, focal | <microscopy> A plane through the focal point perpendicular to the principle axis of a lens or mirror. (05 Aug 1998) |
| positive focal length | <microscopy> Any lens which converges parallel rays to a focus at the back of the lens is a positive lens and has a positive focal length. The focal length is measured from the second principal point of the lens to the point on the lens axis where the rays from an infinitely distant point are brought to focus. See: negative focal length. (05 Aug 1998) |
| posterior focal point | The point of a compound optical system where parallel rays entering the system are focused. (05 Mar 2000) |