scholarly journals Gamma Flux in 14C Laboratories

Radiocarbon ◽  
1992 ◽  
Vol 34 (3) ◽  
pp. 428-430 ◽  
Author(s):  
Páll Theodórsson ◽  
Lauri Kaihola ◽  
H. H. Loosli ◽  
José M. Rodríguez
Keyword(s):  
Gamma Radiation ◽  
Radiocarbon Dating ◽  
Radiation Flux ◽  
Cosmic Ray ◽  
Cosmogenic Nuclides ◽  
Collaborative Group ◽  
Counting System ◽  
Γ Radiation ◽  
Gamma Flux ◽  
Anticoincidence Counting

An informal collaborative group of radiocarbon dating laboratories, the Low-Level Club, has been established to measure the gamma radiation flux and to test the efficiency of the anticoincidence counting system in laboratories with a NaI detector unit. The detector will record gamma radiation from cosmogenic nuclides, muons and secondary γ radiation formed in the passive shield by charged cosmic-ray particles. We present here the first phase of this work.

scholarly journals Facile preparation of new polystyrene leucomalachite green thick films and study of their radiochromic behavior for low doses of gamma radiation

2017 ◽  
Vol 5 (2) ◽  
pp. 80
Author(s):  
Anuradha Bera ◽  
Shatrughan Malav ◽  
Bajrang Lal Tiwari ◽  
Shyam Govind Vaijapurkar
Keyword(s):  
Film Thickness ◽  
Gamma Radiation ◽  
Thick Films ◽  
Radiation Processing ◽  
Γ Radiation ◽  
Dye Loading ◽  
Leucomalachite Green ◽  
Colour Development ◽  
Green Coloration ◽  
Potential Use

Colourless polystyrene-leucomalachite green (PS-LMG) thick films containing a suitable chloroalkane were prepared by a fast and facile casting method, and were investigated for their radio chromic response behavior under the influence of 1.25 MeV γ-radiation. Their gamma response was studied in the 0.05 kGy to 10 kGy range to evaluate their suitability for potential use as the dosimeter in the radiation processing industries. The films were found to undergo a visibly distinct green coloration in the studied range, with the colour intensity increasing with an increase in the total dose. The radiochromic response of these films when investigated as a function of film thickness showed that the colour development as well as the linearity of the response was markedly affected by the thickness of the films. The effect of dye loading and the chloroalkane concentration on the radiochromic response of these films were also investigated. Depending upon the film thickness and reactant concentrations, the films were found to be capable of visually detecting gamma radiation doses as low as few tens of grays.

scholarly journals Differential expression of NPM, GSTA3, and GNMT in mouse liver following long-term in vivo irradiation by means of uranium tailings

2018 ◽  
Vol 38 (5) ◽  
Author(s):  
Lan Yi ◽  
Hongxiang Mu ◽  
Nan Hu ◽  
Jing Sun ◽  
Jie Yin ◽  
...  
Keyword(s):  
Gamma Radiation ◽  
Radiation Exposure ◽  
Central Vein ◽  
Glutathione S Transferase ◽  
Γ Radiation ◽  
Dose Rates ◽  
Living Organisms ◽  
Uranium Tailings

Uranium tailings (UT) are formed as a byproduct of uranium mining and are of potential risk to living organisms. In the present study, we sought to identify potential biomarkers associated with chronic exposure to low dose rate γ radiation originating from UT. We exposed C57BL/6J mice to 30, 100, or 250 μGy/h of gamma radiation originating from UT samples. Nine animals were included in each treatment group. We observed that the liver central vein was significantly enlarged in mice exposed to dose rates of 100 and 250 μGy/h, when compared with nonirradiated controls. Using proteomic techniques, we identified 18 proteins that were differentially expressed (by a factor of at least 2.5-fold) in exposed animals, when compared with controls. We chose glycine N-methyltransferase (GNMT), glutathione S-transferase A3 (GSTA3), and nucleophosmin (NPM) for further investigations. Our data showed that GNMT (at 100 and 250 μGy/h) and NPM (at 250 μGy/h) were up-regulated, and GSTA3 was down-regulated in all of the irradiated groups, indicating that their expression is modulated by chronic gamma radiation exposure. GNMT, GSTA3, and NPM may therefore prove useful as biomarkers of gamma radiation exposure associated with UT. The mechanisms underlying those changes need to be further studied.

scholarly journals GAMMA-RADIATION SPECTRA OF 1200 MeV ELECTRONS IN THICK BERYLLIUM, SILICON AND TUNGSTEN SINGLE CRYSTALS

2019 ◽  
pp. 86-93
Author(s):  
G. L. Bochek ◽  
O. S. Deiev ◽  
V. I. Kulibaba ◽  
N. I. Maslov ◽  
V. D. Ovchinnik ◽  
...  
Keyword(s):  
Gamma Radiation ◽  
Single Crystals ◽  
Angular Distributions ◽  
Γ Radiation ◽  
Radiation Spectra ◽  
Solid Angles ◽  
Crystallographic Axes ◽  
And Tungsten

Gamma radiation spectra of 1200 MeV electrons from the single crystals of the beryllium 1.2 mm thick, silicon 1.5 mm and 15 mm thick and tungsten 1.18 mm thick along of the crystallographic axes were measured. Also spectral-angular distributions of gamma radiation from the silicon single crystals 1.5 mm thick along of the crystallographic axes < 100 >, < 110 > and < 111 > were measured. On the basis of these measurements the γ-radiation spectra for the different solid angles up to 6.97 × 10−6 sr were obtained.

scholarly journals Isotropic Gamma Radiation and the Metagalactic Cosmic Ray Intensity

Nature ◽  
1968 ◽  
Vol 220 (5168) ◽  
pp. 675-676 ◽  
Author(s):  
F. W. STECKER
Keyword(s):  
Gamma Radiation ◽  
Cosmic Ray ◽  
Cosmic Ray Intensity

scholarly journals University of Lund Radiocarbon Dates I

Radiocarbon ◽  
1968 ◽  
Vol 10 (1) ◽  
pp. 36-54 ◽  
Author(s):  
Soren Håkansson
Keyword(s):  
Boric Acid ◽  
Radiocarbon Dating ◽  
Cosmic Ray ◽  
Paraffin Wax ◽  
Radiocarbon Dates ◽  
Proportional Counters ◽  
The University

Plans for a radiocarbon dating laboratory at the University of Lund were initiated by Tage Nilsson and Holger Arbman in 1962. Work was begun in 1964 and at the end of 1965 most of the dating equipment was installed. Dating began in 1966 after careful testing of counting electronics and counters.The dating system has two 1-L copper-walled proportional counters of Östlund-Engstrand construction (for details see Stockholm V. p. 204, Fig. 1) surrounded by 2.5 cm of selected lead, followed by a ring of 23 cosmic-ray Geiger counters (model HZ-100, Zentralwerkstatt Göttingen). On all sides are at least 20 cm of iron. Above and on both long sides of the counters are 10 cm of paraffin wax with about 12% boric acid between the iron layers.

scholarly journals Interplay among p21Waf1/Cip1, MUSASHI-1 and Krüppel-like factor 4 in activation of Bmi1-CreER reserve intestinal stem cells after gamma radiation-induced injury

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Emilia J. Orzechowska ◽  
Takahito Katano ◽  
Agnieszka B. Bialkowska ◽  
Vincent W. Yang
Keyword(s):  
Stem Cells ◽  
Gamma Radiation ◽  
Therapeutic Potential ◽  
Mrna Translation ◽  
Negative Regulator ◽  
Intestinal Stem Cells ◽  
Quiescent State ◽  
Γ Radiation ◽  
Regenerative Response ◽  
Radiation Induced

Abstract Gamma radiation is a commonly used adjuvant treatment for abdominally localized cancer. Since its therapeutic potential is limited due to gastrointestinal (GI) syndrome, elucidation of the regenerative response following radiation-induced gut injury is needed to develop a preventive treatment. Previously, we showed that Krüppel-like factor 4 (KLF4) activates certain quiescent intestinal stem cells (ISCs) marked by Bmi1-CreER to give rise to regenerating crypts following γ irradiation. In the current study, we showed that γ radiation-induced expression of p21Waf1/Cip1 in Bmi1-CreER cells is likely mitigated by MUSASHI-1 (MSI1) acting as a negative regulator of p21Waf1/Cip1 mRNA translation, which promotes exit of the Bmi1-CreER cells from a quiescent state. Additionally, Bmi1-specific Klf4 deletion resulted in decreased numbers of MSI1+ cells in regenerating crypts compared to those of control mice. We showed that KLF4 binds to the Msi1 promoter and activates its expression in vitro. Since MSI1 has been shown to be crucial for crypt regeneration, this finding elucidates a pro-proliferative role of KLF4 during the postirradiation regenerative response. Taken together, our data suggest that the interplay among p21Waf1/Cip1, MSI1 and KLF4 regulates Bmi1-CreER cell survival, exit from quiescence and regenerative potential upon γ radiation-induced injury.

scholarly journals A Beta-Counting System Linked to a Personal Computer

Radiocarbon ◽  
1995 ◽  
Vol 37 (2) ◽  
pp. 767-772 ◽  
Author(s):  
Kunio Omoto
Keyword(s):  
Positive Result ◽  
Significant Role ◽  
Personal Computer ◽  
Radiocarbon Dating ◽  
Counting System ◽  
Long Period ◽  
Beta Counting ◽  
Correction Program ◽  
Fully Automatic ◽  
High Level

The automatic β-counting system plays a significant role in obtaining high-level reproducibility and reliability in conventional radiocarbon dating. I review here the results achieved by using the “Fully Automatic Radiocarbon Dating System” developed by Omoto (1982). Since setting up the system in 1981, I was able not only to save operator time in β counting, but also to obtain accurate dates with only minimal uncertainties. Another positive result was the introduction of the automatic voltage correction program, which produced excellent results for counting sample materials over a long period.

scholarly journals Incorporation of 5-substituted uracil derivatives into nucleic acids. The isolation and γ-radiation-sensitivity of bacteriophage T3 containing the thymine analogue 5-vinyluracil

1980 ◽  
Vol 187 (1) ◽  
pp. 257-260 ◽  
Author(s):  
E T J Chelton ◽  
M Duggan ◽  
R N Hunston ◽  
A S Jones ◽  
M K O'Leary ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Nucleic Acids ◽  
Gamma Radiation ◽  
Radiation Sensitivity ◽  
Γ Radiation ◽  
Uracil Derivatives ◽  
Phage Dna

Bacteriophage T3 was produced in a form that contained 32% of its normal DNA thymine residues replaced with 5-vinyluracil residues by infecting a thymine-requiring strain of Escherichia coli with phage T3 in a medium containing 5-vinyluracil. When 2′-deoxy-5-vinyluridine was added to the medium instead, no incorporation was observed into the phage DNA, and the presence of the deoxyribonucleoside severely decreased the number of viable phage particles produced. The analogue-containing phage, although initially viable, rapidly lost viability when stored, but it was no more sensitive than was normal phage T3 to the effect of gamma-radiation.

Sign in / Sign up

Export Citation Format

Share Document