Irradiation

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irradiation

[i‚rād·ē′ā·shən]
(biophysics)
Subjection of a biological system to sound waves of sufficient intensity to modify their structure or function.
(engineering)
The exposure of a material, object, or patient to x-rays, gamma rays, ultraviolet rays, or other ionizing radiation.
(optics)
An optical illusion which makes bright objects appear larger than they really are.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Irradiation

 

in physiology, the spread of excitation or inhibition in the central nervous system. Irradiation plays an important part in cerebrocortical activity. The irradiation of excitation is manifested most distinctly after strong stimulation, when nerve centers usually not involved in a reflex response are drawn into the process. For example, moderate pain inflicted on the skin of an animal’s foot causes the paw to flex in the talocalcaneal joint. Increasing the force of stimulation causes the leg to flex in the knee and hip joints. In studying the effect of an inhibitory conditioned stimulus, I. P. Pavlov showed that inhibition can also spread (irradiate) in the cells of the cerebral cortex.


Irradiation

 

the apparent enlargement of the dimensions of white (light) objects against a black (dark) background (given the comparatively great brightness of the white object) or, conversely, the apparent diminution of the dimensions of black objects against a white background. (The first instance is called positive irradiation; the second, negative.)

As a result of irradiation, a thin black thread or wire observed against a bright flame seems to be interrupted in that segment, and the bright crescent of the new moon seems to have a larger diameter than the ash-gray disk of the moon seen simultaneously with it. The degree of irradiation increases when the brightness of the light background or object increases. Irradiation is caused by optical defects of the eye (spherical and chromatic aberrations), diffraction phenomena in the eye, and imperfect fixation of the eye on the objects observed.

REFERENCE

Kravkov, S. V. Glaz i ego rabota: Psikhofiziologiia zreniia, gigiena osvesh-cheniia, 4th ed. Moscow-Leningrad, 1950. (Includes bibliography.)
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
In relationship to hematologic malignancies, in the 1989 survey 169 of 497 (34.0%) responded yes as to whether they irradiated for Hodgkin disease.
absoluta, the impact of X-rays on the chromosome number of the [F.sub.1] generation of irradiated males, the morphology and quantity of eupyrene and apyrene sperm bundles in testes of irradiated and non-irradiated males, and the morphology of eupyrene sperm in the bursae copulatrices of non-irradiated females mated with irradiated and non-irradiated males.
Figure 1 shows the tensile strength of un-irradiated and irradiated CS/CC biocomposite films with different CC content.
All irradiated foods have to be labeled as such; look for the phrases "treated with irradiation" or "with irradiation," as well as the radura, which is the international symbol for irradiation.
These interactions were weaker for the irradiated samples.
Our results showed that Hb levels and RBC and WBC counts in the irradiated control group showed significant decreases in comparison with the non-irradiated control and the drug-treated groups (Fig.
Still, the authority is working on developing a proper mechanism to determine if any irradiated food is being imported without mentioning that fact on the labels, he said.
Approximately two million pounds of labeled irradiated fruits and vegetables are sold annually (3), with growing interest in the irradiation of other highly perishable products such as blueberries, raspberries and cherries.
As labeling laws currently stand, any irradiated food must be labeled with a statement such as "treated by irradiation" and must display the irradiation symbol, called a radura.
federal mail were irradiated from November 2001 through April 2008, and the volume of mail irradiated is declining.
stamineus as well as to estimate the concentration of rosmarinic acid of gamma- irradiated O.
We routinely conduct similar surveys to check whether food has been irradiated."