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 It might be outdated or ideologically biased.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 ?
The BCSH Blood Transfusion Task Force also takes the position that "[i]t is not necessary to irradiate blood components for patients undergoing routine surgery, those with solid tumors, HIV infection, autoimmune diseases or after solid organ transplantation ..." and some of these groups were less frequently included in individual organizations' irradiation policies in 2014 when compared with the 1989 survey results.
A commercial electron beam system is used in France to irradiate minced chicken meat.
LIKELIHOOD OF CONSUMERS TO BUY FOOD LABELED "IRRADIATED TO KILL HARMFUL BACTERIA" VERY LIKELY 31.9 SOMEWHAT LIKELY 47.6 NOT LIKELY 19.5 Source: 1998 FMI/GMA "Consumers' View on Food Irradiation" Study CONSUMERS SEE NEED TO IRRADIATE How necessary is irradiation for different products?
After a company decides to irradiate, decisions must be made on operational details: the kind of irradiator to be used and the dosage of radiation it will administer.
Once the ovaries take root, the scientists will irradiate the mice to test whether S1P protects the transplanted egg cells.
The interaction between the ultraviolet light and the uranium produces X rays, which irradiate the pinhead-size, fuel-containing capsule (see illustration).
"But I was also really concerned about what happens when you irradiate the pituitary." When the children were treated, she says, the base of this gland "would have been about 1 to 2 centimeters from where the applicators would have hit." As a result, "the pituitary was getting a lot [of radiation] -- 200 to 400 rem."
In one ongoing study, they irradiate loblolly pines with ultraviolet levels characteristic of a 25 percent thinning in stratospheric ozone--which could occur by the middle of the next century.
With FDA's approval to irradiate eggs to kill harmful bacteria comes a barrage of comments from critics and supporters.
What do you get when you irradiate an apple with 100,000 rads of gamma rays?
To irradiate their product CBBC employs Food Technology Service, the first dedicated commercial food irradiator in the nation and also the irradiator of food consumed in space by NASA astronauts.
To further limit the therapy's damage to healthy tissue, the cancer treatment would not use an external source of X-rays to irradiate the tumor.