scholarly journals The effect of dose-rate on the yield of translocations and dominant lethals following spermatogonial irradiation of mice

1964 ◽  
Vol 5 (3) ◽  
pp. 468-472 ◽  
Author(s):  
R. J. S. Phillips ◽  
A. G. Searle
Keyword(s):  
Dose Rate ◽  
Low Dose ◽  
Previous Experiment ◽  
Male Mice ◽  
Dose Rates ◽  
Neonatal Lethality ◽  
Full Explanation ◽  
X Irradiation ◽  
Dominant Lethals ◽  
Dose Rate Effect

1. F1 (CSH♀ × 101♂) male mice were given 1200 r. 60Co Υ-irradiation over welve weeks and mated twelve weeks after the end of irradiation. The incidences of foetal and neonatal lethality and of semi-sterility in their offspring were compared with those in controls.2. Embryonic survival to 15 days in the irradiated series was 98·2% that of controls, while the incidence of semi-sterility was 0·9% compared with nil in the controls. Neither of these differences is significant.3. Comparison of these results with the significant rates of induction of dominant lethals and translocations in a previous experiment, in which a dose of 1200 r. acute x-irradiation was given to males of the same hybrid stock, show the existence of a dose-rate effect. Its magnitude cannot at present be accurately estimated.4. The reasons for this effect are discussed. It is concluded that the main cause of the lowered translocation yield is that restitution of breaks will be favoured at low dose-rates, with less opportunity for the formation of interchanges. This could partly account for the lowered rate of induction of dominant lethals as well, but a full explanation is not yet possible.

scholarly journals Serum Metabolomic Alterations Associated with Cesium-137 Internal Emitter Delivered in Various Dose Rates

Metabolites ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 270
Author(s):  
Heng-Hong Li ◽  
Yun-Tien Lin ◽  
Evagelia C. Laiakis ◽  
Maryam Goudarzi ◽  
Waylon Weber ◽  
...  
Keyword(s):  
Dose Rate ◽  
Cumulative Dose ◽  
Low Dose ◽  
Biological Effects ◽  
Serum Samples ◽  
Dose Rates ◽  
Sphingosine 1 Phosphate ◽  
Cesium 137 ◽  
Dose Rate Effect ◽  
Medium Dose

Our laboratory and others have use radiation metabolomics to assess responses in order to develop biomarkers reflecting exposure and level of injury. To expand the types of exposure and compare to previously published results, metabolomic analysis has been carried out using serum samples from mice exposed to 137Cs internal emitters. Animals were injected intraperitoneally with 137CsCl solutions of varying radioactivity, and the absorbed doses were calculated. To determine the dose rate effect, serum samples were collected at 2, 3, 5, 7, and 14 days after injection. Based on the time for each group receiving the cumulative dose of 4 Gy, the dose rate for each group was determined. The dose rates analyzed were 0.16 Gy/day (low), 0.69 Gy/day (medium), and 1.25 Gy/day (high). The results indicated that at a cumulative dose of 4 Gy, the low dose rate group had the least number of statistically significantly differential spectral features. Some identified metabolites showed common changes for different dose rates. For example, significantly altered levels of oleamide and sphingosine 1-phosphate were seen in all three groups. On the other hand, the intensity of three amino acids, Isoleucine, Phenylalanine and Arginine, significantly decreased only in the medium dose rate group. These findings have the potential to be used in assessing the exposure and the biological effects of internal emitters.

scholarly journals The Effect of Low Dose-Rate Irradiation on the Microstructure of 304 Stainless Steel

1998 ◽  
Vol 540 ◽  
Author(s):  
J. I. Cole ◽  
T. R. Allen
Keyword(s):  
Stainless Steel ◽  
Dose Rate ◽  
Low Dose ◽  
Rate Effect ◽  
304 Stainless Steel ◽  
Microstructural Development ◽  
Dose Rates ◽  
Low Dose Rate ◽  
Radiation Induced ◽  
Dose Rate Effect

AbstractChanges in mechanical and corrosion properties caused by the development of radiation-induced microstructures have relevance to the aging and lifetime extension of light water reactors (LWR‘s). However, much of the current data related to microstructural development in irradiated metals are generated from studies carried out at much higher dose-rates than encountered in LWR‘s. An opportunity exists to study the influence of low dose-rate irradiation on microstructural development for a variety of structural and surveillance materials extracted from the experimental breeder reactor EBR-lI. In this study, irradiated 304 stainless steel hexagonal “hex” duct material is examined in order to compare microstructures in the dose-rate range of 10−7 - 10−9 dpa/sec. The samples, taken from the reflector locations in EBR-II, experienced a total dose between 10 and 12 dpa at a temperature of ∼375 °C. Transmission electron microscopy (TEM) analysis reveals that there is a moderate dose-rate effect on microstructural development for samples irradiated in the range of 2 × 10−8 to 4 × 10−8. dpa/sec, however a substantial dose-rate effect exists between dose-rates of 2 × 10−8 and 1 × 10−9 dpa/sec Results detail the development of the microstructure in terms of radiation-induced cavities, dislocations, and precipitates.

Activated human N-ras oncogene enhances x-irradiation repair of mammalian cells in vitro less effectively at low dose rate

1985 ◽  
Vol 8 (6) ◽  
pp. 517-522 ◽  
Author(s):  
T. J. FitzGerald ◽  
C. Daugherty ◽  
K. Kase ◽  
L. A. Rothstein ◽  
M. McKenna ◽  
...  
Keyword(s):  
Dose Rate ◽  
Mammalian Cells ◽  
Low Dose ◽  
Ras Oncogene ◽  
Low Dose Rate ◽  
X Irradiation

The conversion model of low dose rate effect in bipolar transistors

2009 ◽  
Author(s):  
V. S. Pershenkov ◽  
D. V. Savchenkov ◽  
A. S. Bakerenkov ◽  
V. N. Ulimov ◽  
A. Y. Nikiforov ◽  
...  
Keyword(s):  
Dose Rate ◽  
Low Dose ◽  
Bipolar Transistors ◽  
Rate Effect ◽  
Conversion Model ◽  
Low Dose Rate ◽  
Dose Rate Effect

Evidence for dose and dose rate effects in human and animal radiation studies

2018 ◽  
Vol 47 (3-4) ◽  
pp. 97-112 ◽  
Author(s):  
M.P. Little
Keyword(s):  
Dose Rate ◽  
Dose Response ◽  
Low Dose ◽  
Atomic Bomb ◽  
Dose Range ◽  
Quadratic Model ◽  
Linear Quadratic ◽  
Dose Rates ◽  
Atomic Bomb Survivors ◽  
Linear Quadratic Model

For stochastic effects such as cancer, linear-quadratic models of dose are often used to extrapolate from the experience of the Japanese atomic bomb survivors to estimate risks from low doses and low dose rates. The low dose extrapolation factor (LDEF), which consists of the ratio of the low dose slope (as derived via fitting a linear-quadratic model) to the slope of the straight line fitted to a specific dose range, is used to derive the degree of overestimation (if LDEF > 1) or underestimation (if LDEF < 1) of low dose risk by linear extrapolation from effects at higher doses. Likewise, a dose rate extrapolation factor (DREF) can be defined, consisting of the ratio of the low dose slopes at high and low dose rates. This paper reviews a variety of human and animal data for cancer and non-cancer endpoints to assess evidence for curvature in the dose response (i.e. LDEF) and modifications of the dose response by dose rate (i.e. DREF). The JANUS mouse data imply that LDEF is approximately 0.2–0.8 and DREF is approximately 1.2–2.3 for many tumours following gamma exposure, with corresponding figures of approximately 0.1–0.9 and 0.0–0.2 following neutron exposure. This paper also cursorily reviews human data which allow direct estimates of low dose and low dose rate risk.

BIOSYNTHESIS OF QUERCETIN IN BUCKWHEAT: PART III

1960 ◽  
Vol 38 (1) ◽  
pp. 559-567 ◽  
Author(s):  
J. E. Watkin ◽  
A. C. Neish
Keyword(s):  
Dose Rate ◽  
Low Dose ◽  
Optimal Dose ◽  
Phenyllactic Acid ◽  
Maximum Percentage ◽  
Dose Rates ◽  
Percentage Conversion

The effect on the conversion of carbon14 to quercetin by a buckwheat plant caused by variation in the dose rate of a carbon 14-labelled precursor in μmoles over a 100-fold range has been studied. The results expressed as dilution of carbon14 varied over a 200-fold range for the same precursor with most of the variation being found at low dose rates. When expressed as the percentage of administered carbon14 converted to quercetin the results for acetate, D-glucose, and L-phenyllactic acid were mostly constant over this range but L-phenylalanine had a maximum percentage conversion or an optimal dose rate. An explanation of the results in metabolic terms has been attempted.It is recommended that the "percentage of C14 converted" be used to express results in plant biosynthetic work.

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