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2022 ◽  
Vol 12 (2) ◽  
pp. 637
Author(s):  
Entesar Almogait ◽  
Aljawhara H. Almuqrin ◽  
Nourah Alhammad ◽  
M. I. Sayyed

A sensitization procedure is used to enhance the thermoluminescence (TL) sensitivity of phyllite to emit radiation. Phyllite is a type of foliated metamorphic rock made from slate. This study examines naturally grown phyllite rock, which had not been previously studied. Using a Thermo 3500 manual reader, the TL sensitivity of phyllite as a function of dosage was measured. The doses required to perform this study were administered using a 60Co source. The statistical regression test of the data had a significance level of p < 0.05. The study also included thermal and pre-dose effects. Using the sensitization procedure, the nonlinearity in TL dose–response was removed, and the sensitivity was increased 44 times that of its original value. The fading study showed a dependence on the test dose. According to the obtained results, the combination of linear dose–response and high sensitivity to gamma radiation makes phyllite an important rock for dating and retrospective dosimetry.


2021 ◽  
Vol 53 (2) ◽  
pp. 36-46
Author(s):  
Fabián Soto ◽  
Patricia Peñaloza ◽  
Eduardo Oyanedel ◽  
Flavia Schiappacasse ◽  
Oscar Durán ◽  
...  

Selliera radicans is a creeping plant native to Chile, New Zealand and Australia. It is increasingly used in the ornamental industry, and there is interest in breeding it to create commercial varieties. The aim of this study was to determine the effects of different doses of gamma radiation applied to the seeds on the germination and development of seedlings (M1) and the LD50 of two accessions of Selliera radicans for use in the induction of mutations. Seeds of the Vichuquén and La Serena accessions were exposed to 0, 100, 200, 300, 400, 500, 600 and 700 Gy from a 60Co source. Weekly germination percentages along with seedling numbers and lengths were recorded. Vichuquén seeds were more sensitive to this physical agent. The LD50 was 243.9 Gy for Vichuquén and 445.6 Gy for La Serena. Seedling lengths reached almost 4 mm for Vichuquén and 11.3 mm for La Serena at 12 weeks after sowing. Doses lower than 200 Gy are recommended since higher doses do not allow the development of seedlings to the extended cotyledon stage. Highlights: This is the first radiosensitivity study for the Goodeniaceae family and therefore for the Selliera genus. This study shows the specific effect of gamma radiation at the level of germination and seedling formation according to accession of origin. This study could be used for the genetic improvement of Selliera radicans via the induction of mutations.


2021 ◽  
Vol 11 (9) ◽  
pp. 4236
Author(s):  
Cristina Florentina Pelcaru ◽  
Mihaela Ene ◽  
Alina-Maria Petrache ◽  
Daniel Constantin Neguț

Environmental changes generate free radicals and reactive oxygen species (ROS), resulting in abiotic stress in plants and fungi. Gamma ionizing radiation generates a significant amount of free radicals and ROS, thereby simulating natural environmental stressors. We used a 60Co source of radiation to experimentally induce oxidative stress in living mycelium mass of the medicinal fungus Fomes fomentarius, in order to obtain a late response of stress tolerance by means of bioactive compounds synthesis. We measured the response at 24, 48, and 72 h after the irradiation. The highest improvement was found 24 h after exposure for antioxidant activity and for total phenolic compounds of methanolic extract, with a 1.89- and 1.64-fold increase, respectively. The total flavonoids in methanolic extract increased 1.68 times after 48 h from treatment and presented a more stable raising in the assessed time-lapse. For the three analyzed parameters, 300 Gy was the optimum absorbed dose to trigger a beneficial response, with potentially applications in pharmaceutics and nutraceutics. Gamma irradiation can be used as a biotechnological tool to direct the secondary metabolites synthesis upregulation in medicinal mushroom living mycelium.


2021 ◽  
Vol 65 (5) ◽  
pp. 12-20
Author(s):  
V. Nugis ◽  
G Snigiryova ◽  
E. Lomonosova ◽  
M. Kozlova ◽  
V. Nikitina

Purpose: Plotting dose-effect curves for translocations identified using the tricolor FISH method based on the results of cytogenetic analysis of cultures of peripheral blood lymphocytes of healthy donors after in vitro gamma irradiation. Material and methods: Venous blood was obtained from three donors (2 men and 1 woman aged from 28 to 41 years) and subjected to in vitro gamma irradiation from a 60Co source at doses of 0.10; 0.15; 0.25; 0.35; 0.50; 0.75; 1.00; 1.50; 2.00 and 3.00 Gy at 37 ° C (dose rate 0.5 Gy / min). For tricolor FISH staining, two different sets of DNA probes were used for chromosome pairs 1, 4, 12 and 2, 3, 8. Metaphases with a quasi-diploid number of chromosomes (40-46) and a complete set of all FISH-stained chromosomes, taking into account their total length, were selected for analysis. Differentiation of stable and unstable cells was also carried out. In the cytogenetic analysis, traditional terminology was used with the designation of translocations as reciprocal (complete, two-sided), non-reciprocal (terminal, incomplete, or unilateral), or interstitial. Results: The obtained numerical data were used to statistically compare the frequencies of FISH-recorded translocations when using different sets of DNA probes, when calculating of chromosome aberrations were in all (unstable and stable) and stable metaphase cells, when comparing of the frequencies of FISH-recorded translocations and dicentrics, and assessing of the contribution of the level of translocations between FISH-stained chromosome pairs in the total translocation frequency. The plotted dose-effect curves generally corresponded to the linear-quadratic form. Conclusion: Dose dependences obtained for translocations using two different selected tricolor sets of DNA probes did not differ statistically significantly. At the same time, cytogenetic analysis of only stable metaphase cells revealed a tendency to register lower levels of translocations than when analyzing all cells (unstable and stable ), at the highest doses of 2 and 3 Gy. The levels of dicentrics formed with the participation of FISH-stained chromosomes were significantly lower than the number of observed translocations. The quantitative contribution of translocations between FISH-stained pairs of chromosomes turned out to be very low, which clearly does not contribute to an increase in the sensitivity of the FISH method of retrospective dose estimation as compared to its one-color version. At the same time, the three-color FISH-staining makes it possible to identify such variants of chromosomal rearrangements that are not recorded using the one-color FISH method.


2021 ◽  
pp. 60-65
Author(s):  
R.S. Ismayilova ◽  
M.M. Kuliev ◽  
G.A. Akhundova

The effect on concentration of the nanofiller α-SiO2 filler and irradiation on the FTIR spectra of pure films polymer (ultra-high molecular weight polyethylene (UHMWPE)) and doped them this α-SiO2 with different concentration (0, 1, 3, 5 vol.%) were investigated using FTIR technique. The samples were irradiated for different doses like 0, 50, and 100 kGy by 60Co source with a dose rate of approximately 3.3∙10-3 kGy/h at room temperature. The correlation of absorption bands with occurrence of corresponding groups was carried out. The occurrence of a series of a characteristic absorptions bands of composites was shown.


Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 849
Author(s):  
Dencho Spassov ◽  
Albena Paskaleva ◽  
Elżbieta Guziewicz ◽  
Vojkan Davidović ◽  
Srboljub Stanković ◽  
...  

High-k dielectric stacks are regarded as a promising information storage media in the Charge Trapping Non-Volatile Memories, which are the most viable alternative to the standard floating gate memory technology. The implementation of high-k materials in real devices requires (among the other investigations) estimation of their radiation hardness. Here we report the effect of gamma radiation (60Co source, doses of 10 and 10 kGy) on dielectric properties, memory windows, leakage currents and retention characteristics of nanolaminated HfO2/Al2O3 stacks obtained by atomic layer deposition and its relationship with post-deposition annealing in oxygen and nitrogen ambient. The results reveal that depending on the dose, either increase or reduction of all kinds of electrically active defects (i.e., initial oxide charge, fast and slow interface states) can be observed. Radiation generates oxide charges with a different sign in O2 and N2 annealed stacks. The results clearly demonstrate a substantial increase in memory windows of the as-grown and oxygen treated stacks resulting from enhancement of the electron trapping. The leakage currents and the retention times of O2 annealed stacks are not deteriorated by irradiation, hence these stacks have high radiation tolerance.


2020 ◽  
Vol 62 (1) ◽  
pp. 1-11
Author(s):  
Yoshiharu Tanaka ◽  
Masakazu Furuta

Abstract While the damage to chromosomes and genes induced by high-dose radiation (HDR) has been well researched in many organisms, the effects of low-dose radiation (LDR), defined as a radiation dose of ≤100 mSv, are still being debated. Recent research has suggested that the biological effects of LDR differ from those observed in HDR. To detect the effect of LDR on genes, we selected a gene of Drosophila melanogaster, known as the multiple wing hair (mwh) gene. The hatched heterozygous larvae with genotype mwh/+ were irradiated by γ-rays of a 60Co source. After eclosion, the wing hairs of the heterozygous flies were observed. The area of only one or two mwh cells (small spot) and that of more than three mwh cells (large spot) were counted. The ratio of the two kinds of spots were compared between groups irradiated by different doses including a non-irradiated control group. For the small spot in females, the eruption frequency increased in the groups irradiated with 20–75 mGy, indicating hypersensitivity (HRS) to LDR, while in the groups irradiated with 200 and 300 mGy, the frequency decreased, indicating induced radioresistance (IRR), while in males, 50 and 100 mGy conferred HRS and 75 and 200 mGy conferred IRR. For the large spot in females, 75 mGy conferred HRS and 100–800 mGy conferred IRR. In conclusion, HRS and IRR to LDR was found in Drosophila wing cells by delimiting the dose of γ-rays finely, except in the male large spot.


2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii222-ii222
Author(s):  
Ganesh Shenoy ◽  
Amanda Snyder ◽  
Becky Slagle-Webb ◽  
Savannah Marshall ◽  
Todd Schell ◽  
...  

Abstract The tumor microenvironment in glioblastoma provides cancer cells with favorable conditions to proliferate and invade surrounding tissues. Macrophages comprise a large portion of the glioblastoma tumor microenvironment (TME) both in terms of volume and function. These cells have been reported to influence tumor progression by modulating immune responses, remodeling extracellular matrix, and providing nutrients to cancer cells among numerous other functions. Radiation therapy forms one of the pillars of glioblastoma management along with surgical resection and chemotherapy. Here we investigated the effects of radiation on macrophage iron metabolism. Using mouse bone-marrow-derived macrophages (BMDMs) we performed in-vitro 59Fe radiotracer assays to study how radiation exposure modified iron trafficking in these cells. We found that low dose radiation at 0.25, 0.5, or 2 Gy from a 60Co source stimulated iron release from the BMDMs with maximal release occurring at 0.5 Gy. Moreover, we observed that iron release was dependent on the amount of serum present in culture media with cells cultured in 20% fetal bovine serum (FBS) showing reduced iron release profiles compared to those cultured in 10% or 1% FBS. Since glioblastoma patients exhibit sexually dimorphic survival outcomes, we investigated whether these radiation-induced responses occurred in a sexually dimorphic pattern. At radiation doses of 0.25 Gy we observed that male macrophages tended to release more iron than female macrophages despite no differences in iron uptake between the sexes – raising the question as to whether differential iron trafficking in response to treatment contributes to the poorer survival outcomes observed in males. Our data suggest that delineating how supporting cells such as macrophages respond to glioblastoma treatment regimens may provide insights into addressing mechanisms of treatment resistance and further our understanding of the sexual dimorphism observed in patient outcomes.


Author(s):  
C. Martínez Vieyra ◽  
M.T Olguin ◽  
E. Gutiérrez Segura ◽  
G. López Tellez

The characteristics of the nanoparticles of silver, copper and zinc obtained from two synthetic routes were investigated. A possible future application of these nanoparticles is as bactericidal agents. The reduction methods were Aloe vera extract and gamma ray irradiation with a dose rate of 0.756 kGy/h and a total dose of 40 kGy from a 60Co-source. The chemical species of the nanoparticles (NPs) obtained by Aloe vera extract were Ag, CuO, and ZnO; while the NPs obtained using gamma irradiation were Ag and Cu2O. The precursor to obtaining the nanoparticles and the route of synthesis define the purity, morphology, crystallinity, and chemical speciation of the metal.


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