scholarly journals X-RAY-INDUCED CHROMOSOME ABERRATIONS IN MOUSE DICTYATE OOCYTES. II. FRACTIONATION AND DOSE RATE EFFECTS

Genetics ◽  
1977 ◽  
Vol 87 (4) ◽  
pp. 699-708
Author(s):  
J G Brewen ◽  
H S Payne ◽  
I D Adler
Keyword(s):  
X Rays ◽  
Large Drop ◽  
X Ray ◽  
Split Dose ◽  
Dose Rates ◽  
Dose Rate Effects ◽  
Rate Effects ◽  
Radiation Induced ◽  
Peak Sensitivity ◽  
Specific Locus

ABSTRACT Split-dose experiments were done on maturing dictyate oocytes to determine if the magnitude of the first dose influenced the "rejoining time" of radiation-induced chromosomal lesions. A total dose of 400r was split into various combinations with varying fractionation intervals. The data derived from analyzing interchanges indicate that there is no difference in the rejoining time whether the first dose was 100, 200, or 300r. It thus appears that the radiation dose in the ranges studied does not significantly alter the rate of repair of the chromosomal lesions. This conclusion is contrary to that which has been propounded to explain the nonlinear dose curves obtained for specific locus mutations. Chronic 60Co Υ-ray exposures were given to female mice over an 8-day period. The exposures were delivered during the period of peak sensitivity, i.e., 8-16 days prior to ovulation. The doses given were 117, 240, 348, and 483r. The aberration yields observed were dramatically lower than for comparable doses of acute X rays even when the RBE of Υ rays compared with X rays is taken into account. The large drop in yields at the low dose rates is interpreted as resulting from a large two-track component in the acute curve, and as being independent of effects on repair systems.

scholarly journals Investigation of dose-rate effects and cell-cycle distribution under protracted exposure to ionizing radiation for various dose-rates

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Yusuke Matsuya ◽  
Stephen J. McMahon ◽  
Kaori Tsutsumi ◽  
Kohei Sasaki ◽  
Go Okuyama ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Ionizing Radiation ◽  
Dose Rate ◽  
Cell Cycle Distribution ◽  
Dose Rates ◽  
Dose Rate Effects ◽  
Rate Effects

X-ray radiation-induced amorphization of metal–organic frameworks

2019 ◽  
Vol 21 (23) ◽  
pp. 12389-12395 ◽  
Author(s):  
Remo N. Widmer ◽  
Giulio I. Lampronti ◽  
Nicola Casati ◽  
Stefan Farsang ◽  
Thomas D. Bennett ◽  
...  
Keyword(s):  
Radiation Damage ◽  
Metal Organic Frameworks ◽  
X Rays ◽  
X Ray ◽  
P Accumulation ◽  
Metal Organic ◽  
Radiation Induced ◽  
Crystalline Metal

Accumulation of radiation damage from synchrotron X-rays leads to complete amorphization of the initially crystalline metal–organic frameworks ZIF-4, ZIF-62, and ZIF-zni. The mechanism of this transformation is studied as a function of time and temperature and is shown to be non-isokinetic.

scholarly journals Dose and Dose-rate Effects of X rays and Fission Neutrons on Lymphocyte Apoptosis in p53(+/+) and p53(-/-) Mice

2000 ◽  
Vol 41 (2) ◽  
pp. 113-127 ◽  
Author(s):  
KAZUO FUJIKAWA ◽  
YUKINORI HASEGAWA ◽  
SHINYA MATSUZAWA ◽  
AKIHIRO FUKUNAGA ◽  
TETSUO ITOH ◽  
...  
Keyword(s):  
Dose Rate ◽  
X Rays ◽  
Lymphocyte Apoptosis ◽  
Dose Rate Effects ◽  
Rate Effects ◽  
Fission Neutrons

Dose-Rate Effects for Various Dose Rates of252Cf Radiation on HeLa Cells in Culture

Radiology ◽  
1970 ◽  
Vol 96 (1) ◽  
pp. 171-174 ◽  
Author(s):  
R. G. Fairchild ◽  
R. M. Drew ◽  
H. L. Atkins
Keyword(s):  
Dose Rate ◽  
Hela Cells ◽  
Dose Rates ◽  
Cells In Culture ◽  
Dose Rate Effects ◽  
Rate Effects

Dose rate effects on the radiation induced oxidation of polyethylene

2007 ◽  
Vol 265 (1) ◽  
pp. 221-226 ◽  
Author(s):  
A. Buttafava ◽  
A. Tavares ◽  
M. Arimondi ◽  
A. Zaopo ◽  
S. Nesti ◽  
...  
Keyword(s):  
Dose Rate ◽  
Dose Rate Effects ◽  
Rate Effects ◽  
Radiation Induced

Radiation protection in irradiated dimethylsiloxane polymers

1963 ◽  
Vol 273 (1352) ◽  
pp. 117-132 ◽  
Keyword(s):  
Protective Effect ◽  
Dose Rate ◽  
Reaction Mechanisms ◽  
Radical Reactions ◽  
Gas Evolution ◽  
Dose Rates ◽  
Dose Rate Effects ◽  
Rate Effects ◽  
Colloidal Sulphur ◽  
Dose Rate Effect

Small concentrations of certain additives can greatly modify the effects produced by radiation of macromolecules such as polymers and biological systems. Various mechanisms of protection can be envisaged, and these lead to different kinetics in protection effects. Most published work studies the elimination of the additive, rather than the change in the macromolecule. In previous papers in this series, the dose rate effects expected for radical reactions were observed for anthracene solutions in hexane and cyclohexane. With anthracene in dimethylsiloxane polymers, however, no such dependence was observed. This problem is studied in greater detail in the present paper. The additives studied were anthracene, iodine, sulphur and benzophenone, and their protective effect on the crosslinking of dimethylsiloxane polymer was investigated a t various dose rates. Contrary to generally accepted views on reaction mechanisms no dose-rate effect was observed; anthracene provided no protection against crosslinking, although it was itself destroyed. Iodine and colloidal sulphur provided a considerable measure of protection, but had no effect on gas evolution. Benzophenone also offered protection, but also reduced the gas yield. To explain these very different patterns of behaviour, it is necessary to modify some present views on the nature of the protection offered; this leads to a discussion as to the mechanism of crosslinking.

On the Amorphization of Silicon by Light Ion Implantation: Ion Flux and Substrate Temperature Effects

1990 ◽  
Vol 201 ◽  
Author(s):  
A. Claverie ◽  
A. Roumili ◽  
N. Gessinn ◽  
J. Beauvillain
Keyword(s):  
Electron Microscopy ◽  
Ion Implantation ◽  
Substrate Temperature ◽  
Dose Rate ◽  
Energy Calculation ◽  
Apparent Contradiction ◽  
Near Surface ◽  
Dose Rates ◽  
Dose Rate Effects ◽  
Rate Effects

AbstractIn this work, we have observed by cross-sectional electron microscopy (XTEM) and high resolution electron microscopy (HREM) the kinetics of silicon amorphization during nitrogen and helium bombardments for various dose rates and substrate temperatures. It is shown that the progression of the cla interfaces can be accurately described by the “Critical Damage Energy Density” (CDED) model for both ions at 100°K. At this temperature however, dose rate effects are unimportant. When increasing the substrate temperature up to 300°K, the amorphization efficiency is lowered. At 300°K dose rate effects are important and we show that for higher dose rates, the efficiency of the amorphization process is improved. In this case, the amorphous layers created by helium implantation are situated in the near surface region in apparent contradiction with damage calculations. The present experimental study demonstrates the competition which exists between the generation rate of point defects and the anihilation rate of these defects. Therefore, it is shown that the position of the a-layers created by light ion implantation at room temperature can be predicted by using a three-dimensional damage energy calculation.

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