• Korean Journal of Microbiology
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• v.54 no.1
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• pp.84-86
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• 2018

Cells of Deinococcus puniceus $DY1^T$ are Gram-positive, coccus-shaped, and crimson color-pigmented. Strain $DY1^T$ was isolated from soil irradiated with 5 kGy gamma radiation and showed resistance to UVC and gamma radiation. In this study, we report the complete genome sequence of a bacterium Deinococcus puniceus $DY1^T$ is consist of circular chromosome comprised of 2,971,983 bp, with the G + C content of 62.5%. The complete genome sequence was obtained using the PacBio RS II platform, it included 2,617 coding sequences (CDs), 2,762 genes, and 88 pseudogene.

• Journal of Radiation Industry
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• v.6 no.2
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• pp.153-158
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• 2012

In this research, poly(acrylic acid) (PAAc) hydrogels containing zinc oxide particle were prepared by gamma-ray irradiation. PAAc powder was completely dissolved in distilled water at room temperature. Water-insoluble zinc oxide powder were added into the PAAc solution and stirred until totally dissolved. Finally, the mixture was irradiated by gamma-ray irradiation to make crosslinking. The effects of various parameters such as zinc ions' concentration, irradiation doses were varied and investigated in detail. PAAc hydrogels containing zinc oxide particle were characterized by gel content and swelling ratio. Moreover, the antibacterial properties of this material were evaluated by paper diffusion test against the Gram positive and Gram negative bacteria.

• Journal of Radiation Industry
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• v.9 no.3
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• pp.111-117
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• 2015

In this paper, production of $^{166}Ho$ by double neutron capture from HANARO research reactor was evaluated. This production approach provides $^{166}Ho$ with high specific activity. $^{164}Dy$ is transmuted into $^{165g+m}Dy$ by (n,${\gamma}$) reaction, then $^{165g+m}Dy$ is transmuted into $^{166}Dy$ by (n,${\gamma}$) reaction. At the end of neutron irradiation, population of $^{166}Dy$ atoms reaches highest point. And $^{164}Dy$ exists as a mixture with $^{165m}Dy$, $^{165}Dy$, $^{166}Ho$ and $^{165}Ho$ at this point. To obtain $^{166}Ho$ with high specific activity, Ho isotopes from irradiated target is separated out. Then $^{166}Ho$ decayed from $^{166}Dy$ is eluted at radioactive equilibrium state. At each step, the number of relevant nuclide is calculated by the state equation. The neutron irradiation time for maximum $^{166}Dy$ is calculated for 283 hour. When 100 mg target of $Dy_2O_3$ (96.8% enriched $^{164}Dy$) is used, possible activity of $^{166}Ho$ is 3.54 Ci($1.31{\times}10^{11}Bq$). For separation efficiency of Dy/Ho is 99.99%, $^{166}Ho/Ho$ is 0.62.

• Journal of Radiation Industry
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• v.6 no.1
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• pp.89-94
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• 2012

Three-dimensional network hydrogels were prepared by ${\gamma}$-irradiation of aqueous solutions of poly(vinyl alcohol) (PVA) and glycerol (Gly). Oven-drying was used to measure the gel fraction (G), hydration (H) or swelling behavior (S) of the prepared hydrogels. This study made a hypothesis that hydrogen bonds due to addition of glycerol and change of dry states such as freeze-drying (FD), room-drying (RD) and oven-drying (OD) acts on the G, H, and S. Interesting results on the hydrogen bonding effect in the prepared hydrogels are monitored at different drying conditions. The FD samples have a higher G values with increase in glycerol content as compared with the OD and RD samples. The formation of strong hydrogen bonding network among Gly molecules and hydrogel matrix was considered as the main driving force, resulting in the changes in the G, H, and S of the hydrogels under different drying conditions.

• Journal of Radiation Protection and Research
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• v.44 no.2
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• pp.79-88
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• 2019

Background: The main goal of experiments is to compare various operational and technical characteristics of D-Shuttle semiconductor personal dosimeters of the Japanese company "Chiyoda Technol Corporation" and Harshaw thermoluminescent dosimeters (TLD) manufactured by "Thermo Fisher Scientific" and DTL-02 of the Russian Research and Production Enterprise (RPE) "Doza" by their occupational and calibration exposure at various dose equivalents from 0.5 to 20 mSv of gamma-radiation. Materials and Methods: Besides dosimeters DTL-02, D-Shuttle and Harshaw TLD, there were also used: (1) the primary reference radionuclide source Hopewell Designs IAEA: G10-1-12 with $^{137}Cs$ isotope (an error is not more than 6% and activity is 20 Ci), and (2) the verification device UPGD-2M of RPE "Doza" and installed in the National Center for Expertise and Certification of the Republic of Kazakhstan (Kapchagai, the National Center for Expertise and Certification). Results and Discussion: The main results of researches are the following: (1) TLDs for Harshaw 6600 and DVG-02TM have an approximately equal measurement accuracy of the individual dose equivalents in the range from 0.5 to 20 mSv of gamma-radiation. (2) Advantages of dosimeters for Harshaw 6600 are due to the high measurement productivity and opportunity to indicate the dose on the skin $H_p$(0.07). Advantages of DVG-02TM consist of operation simplicity and lower cost than of Harshaw 6600. (3) D-Shuttles are convenient for use in the current and the operational monitoring of ionizing radiation. Measurement accuracy and 10% linearity of measurements are ensured when D-Shuttle is irradiated with dose equivalents below 1 mSv at the equivalent dose rate not higher than $3mSv{\cdot}hr^{-1}$. This allows using D-Shuttle at a routine technological activity. Conclusion: The obtained results of experiments demonstrate advantages and disadvantages of D-Shuttle semiconductor dosimeters in comparison with two TLD systems of DVG-02TM and Harshaw 6600.

• Nuclear Engineering and Technology
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• v.51 no.1
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• pp.176-189
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• 2019

This paper presents a feasibility study for producing the medical isotope $^{99m}Tc$ using the hazardous and currently wasted radioisotope $^{99}Tc$. This can be achieved with the nuclear resonance fluorescence (NRF) phenomenon, which has recently been made applicable due to high-intensity laser Compton scattering (LCS) photons. In this work, 21 NRF energy states of $^{99}Tc$ have been identified as potential contributors to the photo-production of $^{99m}Tc$ and their NRF cross-sections are evaluated by using the single particle estimate model and the ENSDF data library. The evaluated cross sections are scaled using known measurement data for improved accuracy. The maximum LCS photon energy is adjusted in a way to cover all the significant excited states that may contribute to $^{99m}Tc$ generation. An energy recovery LINAC system is considered as the LCS photon source and the LCS gamma spectrum is optimized by adjusting the electron energy to maximize $^{99m}Tc$ photo-production. The NRF reaction rate for $^{99m}Tc$ is first optimized without considering the photon attenuations such as photo-atomic interactions and self-shielding due to the NRF resonance itself. The change in energy spectrum and intensity due to the photo-atomic reactions has been quantified using the MCNP6 code and then the NRF self-shielding effect was considered to obtain the spectrums that include all the attenuation factors. Simulations show that when a $^{99}Tc$ target is irradiated at an intensity of the order $10^{17}{\gamma}/s$ for 30 h, 2.01 Ci of $^{99m}Tc$ can be produced.

• Composites Research
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• v.22 no.2
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• pp.1-6
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• 2009

The mechanical characteristics of gamma-ray irradiated UHMWPE specimens were investigated under various heat treatment conditions. The heat treatment was performed in the range of annealing and remelting temperatures. The annealing treatment below the temperature of $130^{\circ}C$ hardly induced changes in the tensile strength, the strain at the failure and the hardness. However the remelting treatment above $140^{\circ}C$ deteriorated those mechanical properties. It was shown in an FTIR analysis that the annealing treatment caused some oxidation of free radicals created by the pretreatment of the irradiation. These quantitative data represented by the behavior of mechanical properties might be used as basic informations for the design and analysis of various artificial joints.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.20 no.2
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• pp.171-182
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• 1990

The purpose of this study was to investigate the effects of irradiation on the striated duct cells of the rat submandibular gland ductal tissues which control the characteristics of saliva. For this study, the experimental group was composed of 36 irradiated Sprague Dawley strain rats divided into 8 subgroups 1 hour, 2 hours, 3 hours, 6 hours, 12 hours, 24 hours, 48 hours, 72 hours after irradiation. 4 non-irradiated rats were used as the control group. The experimental animals were singly irradiated with a dose of 18Gy gamma ray to their head and neck region by the Co-6- teletherapy unit and sacrificed after each experimental duration. The specimens were examined with a light microscope with an H-E stain and with a trans- mission electron microscope. The results of this study were as follows. In the light micrograph, a severe atrophic change occurred in the striated duct cells at 2hours after irradiation and gradual recovery occurred from 6 hours after irradiation. 2. The nuclear chromosomes of the striated duct cells were changed granular at 2 hours after irradiation. Recovery was observed at 6 hours after irradiation. Nuclear bodies were also observed from 3 hours after irradiation. 3. The mitochondria of the striated duct cells had indistinct cristae at 2 hours after irradiation, and were degenerated or swollen at 3 hours after irradiation. They recovered, however, from 6 hours, with an increasing number at 48 hours and a regular arrangement was observed at 72 hours after irradiation. 4. The microvilli showed atrophic changes at 2 hours after irradiation and were almost lost at 3 hours after irradiation. They were observed again from 48 hours after irradiation. 5. The rough endoplasmic reticulum and golgi body were not apparent at 1 hour after irradiation and were dilated with degeneration 2 hours after, but intact rough endoplasmic reticulum were observed from 3 hours after irradiation and developed well at 24 hours after irradiation. By the result of this study, showing a mild change in the functional morphology of the salivary striated duct cells immediately following irradiation, it is considered that the many complications which occur after radiation therapy, will disappear in time with the histological and the functional recovery of the glandular tissues.

• Progress in Medical Physics
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• v.27 no.2
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• pp.98-104
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• 2016

We investigated the effect of high dose on the sensitivity of optically stimulated luminance dosimeters (OSLDs) on Co-60 gamma rays and used a commercial OLSD (Landauer, Inc., Glenwood, IL). New OSLDs were chosen arbitrarily and were irradiated with 1 Gy repeatedly. We confirmed the change in the radiation sensitivity after repeated irradiation. The OSLD sensitivity increased up to 3% after irradiating for seven times and decreased continuously after the eighth time. It dropped by approximately 0.35 Gy per irradiation. Finally, after irradiating for 30 times, the OSLD sensitivity decreased by approximately 7%. When the OSLDs were irradiated 10 times with 1 Gy after their irradiation using a high dose of 15 Gy and 30 Gy, their sensitivity decreased by 6% and 12%, respectively, compared to that before high-dose irradiation. The change in the OSLD sensitivity with a high dose could be modeled by an exponential equation. We confirmed the radiation sensitivity variation caused by a high dose, and the irradiation history of dosimeters was considered to reuse OSLDs irradiated with a high dose.

• Journal of radiological science and technology
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• v.40 no.1
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• pp.87-92
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• 2017

The weight of small animal dosimetry has been continuously increased in pre-clinical studies using radiation in small animals. In this study, three-dimensional(3D) small animal phantom was fabricated using 3D printer which has been continuously used and studied in the various fields. The absorbed dose of 3D animal phantom was evaluated by film dosimetry. Previously, the response of film was obtained from the materials used for production of 3D small animal phantom and compared with the bolus used as the tissue equivalent material in the radiotherapy. When irradiated with gamma rays from 0.5 Gy to 6 Gy, it was confirmed that there was a small difference of less than 1% except 0.5 Gy dose. And when small animal phantom was irradiated with 5 Gy, the difference between the irradiated dose and calculated dose from film was within 2%. Based on this study, it would be possible to increase the reliability of dose in pre-clinical studies using irradiation in small animals by evaluating dose of 3D small animal phantom.