Evidence for Reduced Capacity for Damage Accumulation and Repair in Plateau-Phase C3H 10T 1/2 Cells Following Multiple-Dose Irradiation with γ Rays

1986 ◽  
Vol 106 (3) ◽  
pp. 380 ◽  
Author(s):  
Frank Q. H. Ngo ◽  
Kim Youngman ◽  
Shozo Suzuki ◽  
Ipatia Koumoundouros ◽  
George Iliakis
Keyword(s):  
Multiple Dose ◽  
Damage Accumulation ◽  
Plateau Phase ◽  
Dose Irradiation ◽  
Γ Rays

scholarly journals Effect of multiple-dose irradiation on repair capacity in plateau phase C3H 10T1/2 cells.

1990 ◽  
Vol 31 (3) ◽  
pp. 235-245
Author(s):  
NOBUO KUBOTA ◽  
TADASHI IKEGAMI ◽  
TAE IWASAWA ◽  
MASAE KAKEHI ◽  
KENGO MATSUI
Keyword(s):  
Multiple Dose ◽  
Plateau Phase ◽  
Repair Capacity ◽  
Dose Irradiation

The Fine Structure of Irradiated Mouse Heart

1976 ◽  
Vol 34 ◽  
pp. 184-185
Author(s):  
Vivian V. Yang ◽  
S. Phyllis Stearner
Keyword(s):  
Microscopic Level ◽  
Ultrastructural Changes ◽  
Mouse Heart ◽  
Blood Vessel Wall ◽  
Histopathological Changes ◽  
Light Microscopic Level ◽  
Γ Rays ◽  
Fission Neutrons ◽  
Total Body

The heart is generally considered a radioresistant organ, and has received relatively little study after total-body irradiation with doses below the acutely lethal range. Some late damage in the irradiated heart has been described at the light microscopic level. However, since the dimensions of many important structures of the blood vessel wall are submicroscopic, investigators have turned to the electron microscope for adequate visualization of histopathological changes. Our studies are designed to evaluate ultrastructural changes in the mouse heart, particularly in the capillaries and muscle fibers, for 18 months after total-body exposure, and to compare the effects of 240 rad fission neutrons and 788 rad 60Co γ-rays.Three animals from each irradiated group and three control mice were sacrificed by ether inhalation at 4 days, and at 1, 3, 6, 12, and 18 months after irradiation. The thorax was opened and the heart was fixed briefly in situwith Karnofsky's fixative.

No central adrenal insufficiency found in adults with prader-willi syndrome tested by multiple dose metyrapone test

2019 ◽  
Author(s):  
Anna Rosenberg ◽  
Karlijn Pellikaan ◽  
Kirsten Davidse ◽  
Stephany Donze ◽  
Anita Hokken-Koelega ◽  
...  
Keyword(s):  
Adrenal Insufficiency ◽  
Multiple Dose ◽  
Prader Willi Syndrome ◽  
Central Adrenal Insufficiency

Fatigue of Unidirectional Cord-Rubber Composites

1999 ◽  
Vol 27 (1) ◽  
pp. 48-57 ◽  
Author(s):  
Y. Liu ◽  
Z. Wan ◽  
Z. Tian ◽  
X. Du ◽  
J. Jiang ◽  
...  
Keyword(s):  
Damage Accumulation ◽  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Constant Load ◽  
Testing System ◽  
Rubber Composites ◽  
Cycle Frequency ◽  
Periodic Loading ◽  
Fatigue Damage Accumulation ◽  
Rubber Composite

Abstract A fatigue testing system is established with which the real-time recording of stress, strain, temperature, and hysteresis loss of rubbers or cord-rubber composite specimens subjected to periodic loading or extension can be successfully carried out. Several problems are connected with the experimental study of the fatigue of rubber composites. In constant extension cycling, the specimen becomes relaxed because of the viscoelasticity of rubber composites, and the imposed tension-tension deformation becomes complex. In this method, the specimen is unlikely to fail unless the imposed extensions are very large. Constant load cycling can avoid the shortcomings of constant extension cycling. The specially designed clamps ensure that the specimen does not slip when the load retains a constant value. The Deformation and fatigue damage accumulation processes of rubber composites under periodic loading are also examined. Obviously, the effect of cycle frequency on the fatigue life of rubber composites can not be ignored because of the viscoelasticity of constituent materials. The increase of specimen surface temperature is relatively small in the case of 1 Hz, but the temperature can easily reach 100°C at the 8 Hz frequency. A method for evaluating the fatigue behavior of tires is proposed.

Damage accumulation near a hole under low cycle fatigue proceeding from measurements of local deformation response

2020 ◽  
Vol 86 (10) ◽  
pp. 46-55
Author(s):  
S. I. Eleonsky ◽  
Yu. G. Matvienko ◽  
V. S. Pisarev ◽  
A. V. Chernov
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Damage Accumulation ◽  
Stress Ratio ◽  
Low Cycle Fatigue ◽  
Accumulation Process ◽  
Stress Range ◽  
Cycle Fatigue ◽  
Deformation Response

A new destructive method for quantitative determination of the damage accumulation in the vicinity of a stress concentrator has been proposed and verified. Increase of damage degree in local area with a high level of the strain gradient was achieved through preliminary low-cycle pull-push loading of plane specimens with central open holes. The above procedure is performed for three programs at the same stress range (333.3 MPa) and different stress ratio values 0.33, – 0.66 and – 1.0, and vice versa for two programs at the same stress ratio – 0.33 and different stress range 333.3 and 233.3 MPa. This process offers a set of the objects to be considered with different degree of accumulated fatigue damages. The key point of the developed approach consists in the fact that plane specimens with open holes are tested under real operation conditions without a preliminary notching of the specimen initiating the fatigue crack growth. The measured parameters necessary for a quantitative description of the damage accumulation process were obtained by removing the local volume of the material in the form of a sequence of narrow notches at a constant level of external tensile stress. External load can be considered an amplifier enhancing a useful signal responsible for revealing the material damage. The notch is intended for assessing the level of fatigue damage, just as probe holes are used to release residual stress energy in the hole drilling method. Measurements of the deformation response caused by local removing of the material are carried out by electronic speckle-pattern interferometry at different stages of low-cycle fatigue. The transition from measured in-plane displacements to the values of the stress intensity factor (SIF) and the T-stress was carried out on the basis of the relations of linear fracture mechanics. It was shown that the normalized dependences of the stress intensity factor on the durability percentage for the first notch (constructed for four programs of cyclic loading with different parameters), reflect the effect of the stress ratio and stress range of the loading cycle on the rate of damage accumulation. The data were used to obtain the explicit form of the damage accumulation function that quantitatively describes damage accumulation process. The functions were constructed for different stress ratios and stress ranges.

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