Penumbra (disambiguation) — The penumbra is the part of a shadow where the light source is only partially blocked.Penumbra may also refer to:* Penumbra (medicine), surviving tissue at the margin of an ischemic event (such as a stroke) which is in danger of hypoxia and… … Wikipedia
penumbra — The region of partial illumination or radiation caused by light or x rays not originating from a point source; also called geometric unsharpness. [Mod. L., fr. L. paene, almost, + umbra, shadow] * * * pe·num·bra pə nəm brə n, pl brae (.)brē, .brī … Medical dictionary
penumbra field — the region of free space which is irradiated by primary photons coming from only part of the radiation source … Medical dictionary
ischemic penumbra — an area of moderately ischemic brain tissue surrounding an area of more severe ischemia; blood flow to this area may be enhanced in order to prevent the spread of a cerebral infarction. Ischemic penumbra on CT perfusion imaging in acute stroke.… … Medical dictionary
stroke — 1. Any acute clinical event, related to impairment of cerebral circulation, that lasts more than 24 hours. SYN: apoplexy, brain attack. 2. A harmful discharge of lightning, particularly one that affects a human being. 3. A pulsation. 4. To pass… … Medical dictionary
umbra — um·bra (umґbrə) [L. “shadowâ€] 1. the area of a shadow where there is no illumination; cf. penumbra. 2. in radiography, the area of sharp contrast … Medical dictionary
Jack Kevorkian — at UCLA s Royce Hall, January 15, 2011. Born May 26, 1928(1928 05 26) Pontiac, Michigan, U.S. D … Wikipedia
Aloysius Pendergast — This article is about a fictional character. For other uses of the name, see Pendergast. Aloysius Pendergast Aloysius X. L. Pendergast First appearance … Wikipedia
'Til Death Do Us Part (Star Trek: Deep Space Nine) — Til Death Do Us Part Star Trek: Deep Space Nine episode Episode no. Episode 166 Directed by Winrich Kolbe Written … Wikipedia
Stroke — For other uses, see Stroke (disambiguation). Stroke Classification and external resources CT scan slice of the brain showing a right hemispheric ischemic stroke (left side of image). ICD 10 … Wikipedia