(n.) The shadow cast, in an eclipse, where the light is partly, but not wholly, cut off by the intervening body; the space of partial illumination between the umbra, or perfect shadow, on all sides, and the full light.
(n.) The part of a picture where the shade imperceptibly blends with the light.
Example Sentences:
(1) Our analysis showed that the interpolation errors are proportional to the curvature of the dose distribution and are relatively high in regions on either side of, but not including, the steepest part of the penumbra.
(2) Analysis of the penumbra width of cross dose distributions, as a function of field sizes, allowed us to postulate that the dmax shift could be due to the phantom scattered photons, which in turn were generated by the collimator scattered photons.
(3) If true, this is the first demonstration of the ischemic penumbra by MR imaging and may reflect our use of Wistar rats, a new image analysis technique, and ultra-high resolution MR imaging.
(4) The combination for this applicator of sharp penumbra and low out-of-field dose leads to reduced lung and opposite breast doses.
(5) An extracellular acidosis that occurs in the penumbra zone was investigated in vitro as to its role in the formation of cytotoxic cell swelling.
(6) The ischemic thresholds for the initial increase in CMRG and the complete depletion of ATP content represent the metabolic equivalent of the penumbra zone and provide a basis for the evaluation of therapeutic procedures for the treatment of stroke.
(7) If the entire cross-section is blocked, the point will be in the umbra of the shadow; if only a portion of the light is blocked, the point will be in the penumbra of the shadow.
(8) The mechanisms involved in this sequence of events and the role of pH changes in the development of the so-called "ischaemic penumbra" are discussed.
(9) In the light of these findings, we suggest that use of a selective antagonist of LTs may be helpful in reducing the ischemic penumbra during acute cerebral ischemia by controlling the vasogenic edema.
(10) Opening the hinge adjustment restores field flatness, without changing penumbra or the inverse square law behavior of the teletherapy unit.
(11) The area of "penumbra" could be estimated in regions with CBF value just above this threshold.
(12) In the penumbra zone, comparable trends were noted in OER and CMRO2 but the difference in the changes between the two groups did not reach statistical significance.
(13) The agreement is within experimental errors both in the penumbra region and along the central ray of the asymmetric field.
(14) These results confirm the concept of a metabolic penumbra.
(15) These wedges were designed to increase the penumbra width at the field junction from about 1.5 to about 3.5 cm, to achieve dose uniformity.
(16) These studies suggest that 1) the expression of 72-kd heat-shock protein in neurons precedes the development of ischemic cellular alterations detectable by conventional hematoxylin and eosin light microscopy methods; 2) there is a hierarchy of cell types and anatomic sites that express 72-kd heat-shock protein, and this hierarchy reflects cellular and anatomic vulnerability to ischemic cell damage; and 3) 72-kd heat-shock protein induction in neurons bordering a necrotic ischemic core may be the morphological equivalent of the ischemic penumbra.
(17) While within the penumbra, some direct sunlight falls on the Moon but little darkening of the disc will be noticed until a few minutes before the Moon begins to enter the umbra at 19:23.
(18) Measurements with the diode interfaced to an X-Y recorder required only a fraction of the time required with the chambers, minimizing error due to change in machine output, and permitted resolution of isodose lines in the penumbra.
(19) A typical spot has a central dark umbra, surrounded by a lighter penumbra.
(20) The rate in the penumbra differed (P = .01) from that in the predicted low-dose region, where scotoma did not increase with time.
Stroke
Definition:
(imp.) Struck.
(v. t.) The act of striking; a blow; a hit; a knock; esp., a violent or hostile attack made with the arm or hand, or with an instrument or weapon.
(v. t.) The result of effect of a striking; injury or affliction; soreness.
(v. t.) The striking of the clock to tell the hour.
(v. t.) A gentle, caressing touch or movement upon something; a stroking.
(v. t.) A mark or dash in writing or printing; a line; the touch of a pen or pencil; as, an up stroke; a firm stroke.
(v. t.) Hence, by extension, an addition or amandment to a written composition; a touch; as, to give some finishing strokes to an essay.
(v. t.) A sudden attack of disease; especially, a fatal attack; a severe disaster; any affliction or calamity, especially a sudden one; as, a stroke of apoplexy; the stroke of death.
(v. t.) A throb or beat, as of the heart.
(v. t.) One of a series of beats or movements against a resisting medium, by means of which movement through or upon it is accomplished; as, the stroke of a bird's wing in flying, or an oar in rowing, of a skater, swimmer, etc.
(v. t.) The rate of succession of stroke; as, a quick stroke.
(v. t.) The oar nearest the stern of a boat, by which the other oars are guided; -- called also stroke oar.
(v. t.) The rower who pulls the stroke oar; the strokesman.
(v. t.) A powerful or sudden effort by which something is done, produced, or accomplished; also, something done or accomplished by such an effort; as, a stroke of genius; a stroke of business; a master stroke of policy.
(v. t.) The movement, in either direction, of the piston plunger, piston rod, crosshead, etc., as of a steam engine or a pump, in which these parts have a reciprocating motion; as, the forward stroke of a piston; also, the entire distance passed through, as by a piston, in such a movement; as, the piston is at half stroke.
(v. t.) Power; influence.
(v. t.) Appetite.
(v. t.) To strike.
(v. t.) To rib gently in one direction; especially, to pass the hand gently over by way of expressing kindness or tenderness; to caress; to soothe.
(v. t.) To make smooth by rubbing.
(v. t.) To give a finely fluted surface to.
(v. t.) To row the stroke oar of; as, to stroke a boat.
Example Sentences:
(1) The major treatable risk factors in thromboembolic stroke are hypertension and transient ischemic attacks (TIA).
(2) In the stage 24 chick embryo, a paced increase in heart rate reduces stroke volume, presumably by rate-dependent decrease in passive filling.
(3) We studied the effects of the localisation and size of ischemic brain infarcts and the influence of potential covariates (gender, age, time since infarction, physical handicap, cognitive impairment, aphasia, cortical atrophy and ventricular size) on 'post-stroke depression'.
(4) Serum sialic acid concentration predicts both death from CHD and stroke in men and women independent of age.
(5) Cardiovascular disease event rates will be assessed through continuous community surveillance of fatal and nonfatal myocardial infarction and stroke.
(6) Five late strokes were ipsilateral (1.8%) and six were contralateral (2.1%) to the operated carotid artery.
(7) Diabetic retinopathy (an index of microangiopathy) and absence of peripheral pulses, amputation, or history of myocardial infarction, stroke, or transient ischemic attacks (as evidence of macroangiopathy) caused surprisingly little increase in relative risk for cardiovascular death.
(8) Urinary incontinence present between 7 and 10 days after stroke was the most important adverse prognostic factor both for survival and for recovery of function.
(9) Acetylsalicylic acid has been shown to reduce significantly stroke, death and stroke-related death in men, with no detectable benefit for women.
(10) Atrophy was present in 44% of TIA patients, 68% of PRIND patients and 82% of completed stroke patients.
(11) On the basis of clinical symptoms and CT scan findings, 66 patients were categorized as having sustained a RIND and 187 a stroke.
(12) Recognised risk factors for stroke were found equally in those patients with and without severe events before onset, except that hypertension was rather less common in the patients who had experienced a severe event.
(13) These are risk factors for diabetes, cardiovascular disease and stroke.
(14) Stroke was the cause of 2 and congestive heart failure the cause of 4 deaths.
(15) Combined clinical observations, stroke volume measured by impedance cardiography, and ejection fractions calculated from systolic time intervals, all showed significant improvement in parallel with CoQ10 administration.
(16) He won the Labour candidacy for the Scottish seat of Kilmarnock and Loudon in 1997, within weeks of polling day, after the sitting Labour MP, Willie McKelvey, decided to stand down when he suffered a stroke.
(17) During surgical stimulation cardiac index increased in group A due to an increase in heart rate but remained below control in group B, while stroke volume index was reduced in both groups throughout the whole procedure.
(18) In 2001 Sorensen suffered a stroke, which seriously damaged his eyesight, but he continued to be involved in a number of organisations, including the Council on Foreign Relations and other charitable and public bodies, until a second stroke in October 2010.
(19) Two hundred and forty-one residents were examined for carotid bruits and signs of previous stroke.
(20) One hundred ten atherosclerotic occlusions of the internal carotid artery (ICA) were found in 106 patients in group I. Fifty-one percent of these patients had a history of stroke before arteriography, 24% had transient ischemic attacks (TIAs) or amaurosis fugax (AF), and 12% had nonhemispheric symptoms.