• Nuclear Engineering and Technology
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• v.51 no.1
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• pp.269-274
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• 2019

$^{64}Cu$ is a favorable radionuclide in nuclear medicine applications because of its unique characteristics such as three types of decay (electron capture, ${\beta}^-$ and ${\beta}^+$) and 12.7 h half-life. Production of $^{64}Cu$ by irradiation $^{nat}Cu$ and $^{nat}CuNPs$ in Tehran Research Reactor was investigated. The characteristics of copper nanoparticles were investigated with SEM, TEM and XRD analysis. The cross section of $^{63}Cu(n,{\gamma})^{64}Cu$ reaction was done with TALYS-1.8 code. The activity value of $^{64}Cu$ was calculated with theoretical approach and MCNPX-2.6 code. The results were compared with related experimental results which showed good adaptations between them.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.16
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• pp.7103-7110
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• 2015

The present study was conducted to investigate the effect of ${\gamma}$-radiation alone or combined with a cytotoxic drug, simvastatin, on viability and cell cycling of a myeloma cell line. P3NS1 myeloma cells were treated with the selected dose of simvastatin ($0.1{\mu}M/l$) 24 hours prior to ${\gamma}$-irradiation (0.25, 0.5 and 1Gy). The cell viability, induction of apoptosis, cell death, cell cycling, generation of ROS, and expression of P53, Bax, Bcl2, caspase3, PARP1 and Fas genes were estimated. The results indicated that simvastatin ($0.1{\mu}M/l$) treatment for 24 hours prior to ${\gamma}$-irradiation increased cell death to 37.5% as compared to 4.81% by radiation (0.5Gy) alone. It was found that simvastatin treatment before irradiation caused arrest of cells in G0/G1 and G2/M phases as assessed using flow cytometry. Interestingly, simvastatin treatment of P3NS1 cells increased the intracellular ROS production and decreased antioxidant enzyme activity with increased P53, Bax and Caspase3 gene expression while that of Bcl2 was decreased. Consequently, our results indicated that pre-treatment with simvastatin increased radio sensitivity of myeloma tumor cells in addition to apoptotic effects through an intrinsic mitochondrial pathway.

• Korean Journal of Medicinal Crop Science
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• v.14 no.6
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• pp.360-366
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• 2006

To investigate the effect of culture conditions on growth and ginsenosides accumulation, we cultured the ginseng hairy root under three different media, white light or ultra-violet irradiation. The MS/B5 medium containning MS basal salt and B5 vitamin was good for the growth and ginsenoside accumulation. The light during the culture period of ginseng hairy root was irradiated. The growth was abundant in the ginseng hairy root cultured in dark. But the ginsenosides accumulation was higher than in the ginseng hairy root cultured in the light irradiation. When the ginseng hairy root was cultured in 20 L bioreactor, the ginsenosides accumulation was observed at 34% higher than the hairy root cultured in dark. UV irradiated the ginseng hairy root during the culture period. The long time irradiation of UV was caused decreasing the growth of ginseng hairy root, but the accumulation of ginsenosidess was increased as to the irradiated time.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.2
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• pp.289-295
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• 2009

To develop a safer yogurt for immuno-compromised or allergy patients and to extend shelf-life, a plain yogurt was irradiated with doses of 0, 1, 3, 5, and 10 kGy using a gamma ray and the chemical and microbiological quality and allergenicity change were investigated. There was no difference in the content of protein, total solid, and amino acids of the plain yogurt by irradiation treatment and different storage temperatures (4, 20, and $35^{\circ}C$). The lactic acid bacterial counts of irradiated plain yogurt had approximately 3-decimal reduction at 3 kGy, and no viable cell at 10 kGy regardless of storage time and temperature. The binding ability of rabbit antiserum to milk proteins in irradiated plain yogurt showed that 10 kGy of irradiation produced significantly higher binding ability than other treatments. Sensory evaluation indicated that only appearance of the plain yogurt irradiated at 3 kGy or higher had a lower value than the non-irradiated control when stored at $20^{\circ}C$. Results suggest that irradiation of plain yogurt does not significantly affect the chemical and sensory quality of plain yogurt, but can extend the shelf-life, possibly reduce allergenicity, and provide a safer product.

• Korean Journal of Food Science and Technology
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• v.26 no.2
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• pp.167-171
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• 1994

With a view to improving microbiological quality of spinach powder which is currently used for convenience food production, comparative efficacy of ethylene oxide(EO) fumigation and gamma irradiation was investigated by determining microbial populations and physicochemical quality for treated samples. Spinach powder was contaminated with various microorganisms ranging from $10^{2}/g\;to\;10^{4}/g$, which composed of thermophiles, acid tolerant bacteria, fungi, coliforms, etc. Microorganisms contaminated were destroyed up to undetected levels by gamma irradiation at below 7 kGy. showing the radiosensitivity $D_{10}$ 2.93 kGy on total aerobic bacteria. Ethylene oxide fumigation, however. was found unsatisfactory for physicochemical quality as well as microbial decontamination of the sample. It has been generally observed that influence of optimum-dose range of irradiation on the physicochemical qualities was insignificant, which was proved in the organoleptic evaluations on the stored sample.

• Korean Journal of Food Science and Technology
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• v.33 no.1
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• pp.72-77
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• 2001

The effect of gamma-irradiation on the microbiological and general quality changes of the kochujang(Korean hot pepper paste) was studied. Kochujang was prepared, irradiated at 5, 10 and 20 kGy, and then stored at $25^{\circ}C$ for twelve weeks. The results showed that the Bacillus were decreased by 5 log cycles with dose of 20 kGy with 3.94 kGy of $D_{10}$ value. Yeast and Lactobacillus cells were nearly eliminated by 10 kGy. The formation of $NH_2-nitrogen$ and reducing sugar, enzyme activity, acid production and browning were not affected by gamma irradiation. Therefore, it was considered that the kochujang treated with gamma irradiation maintained better microbial quality than that of the control with storage.

• Korean Journal of Veterinary Research
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• v.45 no.1
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• pp.1-6
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• 2005

In this study we assessed the influences of ultraviolet (UV) light B radiation on epidermal cells by apoptotic sunburn cell (SBC) and the effect of green tea treatment on the inhibition of SBC formation in SKH1-hr mouse. The extent of changes following $200mJ/cm^2$ (0.5 mW/sec) was studied at 0, 3, 6, 12, 18, 24, 30 or 36 hours after exposure. SBCs were recognized by 3 hours after irradiation. There was tendency to increase from 3 hours to 24 hours and decrease from then to 36 hours after irradiation. The mice that received 0, 25, 50, 100, 200, 400 or $800mJ/cm^2$ of UVB were examined 24 hours after irradiation. The SBCs were induced as the radiation dose increases from 0 to $200mJ/cm^2$. A further increase of radiation dose has little further effect. The frequency of UVB ($200mJ/cm^2$)-induced SBC formation was reduced by intraperitoneal injection of green tea extract (p<0.01).

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.10
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• pp.1521-1527
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• 2019

Objective: To study the contribution of plant enzyme and microbial activities on protein degradation in silage, this study evaluated the nitrogen transformation dynamics during ensiling of non- and irradiated alfalfa (Medicago sativa L.) and red clover (Trifolium pratense L.). Methods: Alfalfa and red clover silages were prepared and equally divided into two groups. One group was exposed to ${\gamma}$-irradiation at a recommended dosage (25 Gky). Therefore, four types of silages were produced: i) non-irradiated alfalfa silage; ii) irradiated alfalfa silage; iii) non-irradiated red clover silage; and iv) irradiated red clover silage. These silages were opened for fermentation quality and nitrogen components analyses after 1, 4, 8, and 30 days, respectively. Results: The ${\gamma}$-irradiation successfully suppressed microbial activity, indicated by high pH and no apparent increases in fermentation end products in irradiated silages. All nitrogen components, except for peptide-N, increased throughout the ensiling process. Proteolysis less occurred in red clover silages compared with alfalfa silages, indicated by smaller (p<0.05) increment in peptide-N and free amino acid N (FAA-N) during early stage of ensiling. The ${\gamma}$-irradiation treatment increased (p<0.05) peptide-N and FAA-N in alfalfa silage at day 1, whereas not in red clover silage; these two nitrogen components were higher (p<0.05) between day 4 and day 30 in non-irradiated silages than the irradiated silages. The ammonia nitrogen and non-protein nitrogen were highest in non-irradiated alfalfa silage and lowest in irradiated red clover silage after ensiling. Conclusion: The result of this study indicate that red clover and alfalfa are two forages varying in their nitrogen transformation patterns, especially during early stages of ensiling. Microbial activity plays a certain role in the proteolysis and seems little affected by the presence of polyphenol oxidase in red clover compared with alfalfaa.

• Journal of Radiation Protection and Research
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• v.44 no.2
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• pp.72-78
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• 2019

Background: In the calibration and testing laboratory of Korea Atomic Energy Research Institute, the old X-ray generator used for the production of reference X-ray fields was replaced with a new one. For this newly installed X-ray irradiation system, beam alignment as well as the verification of beam qualities was conducted. Materials and Methods: The existing X-ray generator, Phillips MG325, was replaced with YXLON Y.TU 320-D03 in order to generate reference X-ray fields. Theoretical calculations and Monte Carlo simulations were used to determine initial filter thickness. Beam alignment was performed in three steps to deliver a homogeneous radiation dosage to the target at different distances. Finally, the half-value layers were measured for different X-ray fields to verify beam qualities by using an ion chamber. Results and Discussion: Beam alignment was performed in three steps, and collimators and other components were arranged to maintain the uniformity of the mean air kerma rate within ${\pm}2.5%$ at the effective beam diameter of 28 cm. The beam quality was verified by using half-value layer measurement methods specified by American National Standard Institute (ANSI) N13.11-2009 and International Organization for Standardization (ISO)-4037. For each of the nine beams than can be generated by the new X-ray irradiation system, air kerma rates for X-ray fields of different beam qualifies were measured. The results showed that each air kerma rate and homogeneity coefficient of the first and second half-value layers were within ${\pm}5%$ of the recommended values in the standard documents. Conclusion: The results showed that the new X-ray irradiation system provides beam qualities that are as high as moderate beam qualities offered by National Institute of Standards and Technology in ANSI N13.11-2009 and those for narrow-spectrum series of ISO-4037.

• Nuclear Engineering and Technology
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• v.56 no.4
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• pp.1526-1531
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• 2024

¹³¹I is a fission product produced in a nuclear reactor by irradiating tellurium dioxide, with a half-life of 8.02 day. The most important and widely used method for making ¹³¹I is irradiation using a nuclear reactor and post-irradiation followed by dry distillation. The advantage of the dry distillation process is that the process and the equipment are relatively simple, namely TeO₂ (m.p. 750 ℃), which can withstand heating during reactor irradiation. Based on TeO₂ irradiation by neutron following the technique of dry distillation was explained for production of ¹³¹I on a large scale. A dry distillation followed the radioisotope production operation using the 30 MW GA Siwabessy nuclear reactor to meet national demand. TeO₂ targets are 25 and 50 g irradiated for 87-100 h. The resulting ¹³¹I activity is 20.29339-368.50335GBq. According to the requirements imposed on the radionuclide purity of the preparation, the contribution of ¹³¹I training in the resulting preparation was not less than 99.9 %