• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.7
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• pp.1450-1455
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• 2009

Assumed that an IPTV camera system is to be used as an ad-hoc sensor for the surveillance and diagnostics of safety-critical equipments installed in the in-containment building of the nuclear power plant, an major problem is the presence of high dose-rate gamma irradiation fields inside the one. In order to uses an IPTV camera in such intense gamma radiation environment of the in-containment building, the radiation-weakened devices including a CCD imaging sensor, FPGA, ASIC and microprocessors are to be properly shielded from high dose-rate gamma radiation using the high-density material, lead or tungsten. But the passive elements such as mirror, lens and window, which are placed in the optical path of the CCD imaging sensor, are exposed to a high dose-rate gamma ray source directly. So, the gamma-ray irradiation characteristics of the passive elements, is needed to test. A CCD camera lens, made of glass material, have been gamma irradiated at the dose rate of 4.2 kGy/h during an hour up to a total dose of 4 kGy. The radiation induced color-center in the glass lens is observed. The degradation performance of the gamma irradiated lens is explained using an color component analysis.

• KSBB Journal
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• v.28 no.6
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• pp.415-422
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• 2013

Gamma irradiation (${\gamma}IR$) is widely used for radiotherapy as a treatment of cancer cells although it has a risk to damage normal cells. Inflammation is regarded as one of side effects of ${\gamma}IR$ while the effect of low dose of ${\gamma}IR$ on inflammation has not been researched well. Here, we investigated the inflammatory responses of low dose of ${\gamma}IR$ on murine spleen cells. It was evaluated if ${\gamma}IR$ affected the mitogen-induced lymphocyte proliferation, the regulation of various inflammatory cytokines (IFN-${\gamma}$, IL-2, IL-17, IL-4, IL-10), and the involvement of Ikaros and MAPK/NF-${\kappa}B$ medicated mechanism. Exposure of $^{137}Cs-{\gamma}IR$ below 2 Gy decreased the lymphocytes proliferative response to mitogens (LPS, ConA) except at the lowest dose, 0.05 Gy. IL-17, IL-2 and IL-4 mRNA increased at 0.5 and 2 Gy, but not altered at 0.05 Gy. IL-10, anti-inflammatory cytokine, increased only at 0.05 Gy. In regard to intracellular signaling, p-JNK, p-p38 and p-$I{\kappa}B{\alpha}$ were not changed, whereas the activation of ERK and Ikaros increased at the lowest dose. These results suggest that exposure of ${\gamma}IR$ less than 0.5 Gy (or below 0.05 Gy) has beneficial effects as a radiation hormesis on immune function.

• Journal of radiological science and technology
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• v.13 no.2
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• pp.51-51
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• 1990

This study was undertaken to observe the effects of $^{60}Co\;{\gamma}-irradiation$ on the cell of spermatogenic epithelium in the testis of the chicken. 16-week-old chicken were provided as an experimental group and compared with control group. The experimental group was divided into a single irradiation (800, 1000, 1200 rads) and into three partial irradiation group (800/3, 1000/3, 1200/3 rads). The morphological changes of epithelial cell of the testis were observed by means of hematoxyline and eosin stain. Microstructure of spermatocyte and sperm was observed by means of semithin section of electron microscopic specimen. The results obstained are summerized as follows. 1. Spermatogonia and sertoli cells were found to be isolated from the basal membrane of seminiferous tubules as dose of $^{60}Co\;{\gamma}-irradiation$ was increased. 2. Spermatocytes of pachytene stage were seperated from the cytotplasmic process of sertoil cell in case of 1000 rads of $^{60}Co\;{\gamma}-irradiation$. 3. Normal arrangement of the cell of spermatogenic epithelium was found in control group and only the partial irradiation group of 800 rads. Vaculation in the seminiferous was pronounced in case of a single irradiation group of 800 rads, but the irradiation group of 1000 rads and 1200 rads were found to be damaged severely in both a single and a partial dose.

• The Journal of the Korea Contents Association
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• v.14 no.4
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• pp.249-255
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• 2014

Total body irradiation use one of the pre-treatment as hematopoietic stem cell transplantation in the treatment of leukemia. According to the study of Korean network for organ sharing 2013 report, continue to increase the number of hematopoietic stem cell transplantation. however, the current dose evaluation fall short before treatment. So purpose of this study is Surface dose and deep organ dose evaluation and then find the most ideal conditions when change of the thickness on tissue compensator in TBI. Result, surface dose in 4 MV, SSD 280 cm, compensators thickness 0.5 cm, was measured the highest dose 5.84 mGy/min. And the ideal dose showed when compensator thickness less than 1 cm.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.12
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• pp.1203-1209
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• 2011

In this paper, the degradation evaluation method of VLC (Visible Light Communication) wireless module after high dose rate gamma-ray irradiation using the thermal infrared camera is proposed. First, the heating characteristics of the active devices embedded in the VLC wireless module during the condition of normal operation is monitored by thermal infrared camera. By the image processing technique, the trends of the intensity of the heat emitted by the active devices are calculated and stored. The feature of the blob area including the area of the active devices in the thermal infrared image is extracted and stored. The feature used in this paper is the mean value of the gray levels in the blob area. The same VLC module has been gamma irradiated at the dose rate of about 4.0 kGy/h during 72 hours up to a total dose of 288 kGy. And then, the heating characteristics of the active devices embedded in the VLC wireless module after high dose gamma ray irradiation is observed by thermal infrared camera. The high dose gamma-ray induced degradation of the active devices embedded in the VLC module was evaluated by comparing the mean value of the blob area to the one of the same blob area of the VLC module before the gamma ray irradiation.

• Archives of Pharmacal Research
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• v.20 no.3
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• pp.212-217
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• 1997

Induction of an adaptive response to ionizing radiation in mouse lymphoma (EL4) cells was studied by using cell survival fraction and apoptotic nucleosomal DNA fragmentation as biological end points. Cells in early log phase were pre-exposed to low dose of ${\gamma}$-rays (0.01 Gy) 4 or 20 hrs prior to high dose ${\gamma}$-ray (4, 8 and 12 Gy for cell survival fraction analysis; 8 Gy for DNA fragmentation analysis) irradiation. Then cell survival fractions and the extent of DNA fragmentation were measured. Significant adaptive response, increase in cell survival fraction and decrease in the extent of DNA fragmentation were induced when low and high dose .gamma.-ray irradiation time interval was 4 hr. Addition of protein or RNA synthesis inhibitor, cycloheximide or 5,6-dichloro-1-.betha.-d-ribofuranosylbenzimidazole (DRFB), respectively during adaptation period, the period from low dose ${\gamma}$-ray irradiation to high dose ${\gamma}$-ray irradiation, was able to inhibit the induction of adaptive response, which is the reduction of the extent DNA fragmentation in irradiated EL4 cells. These data suggest that the induction of adaptive response to ionizing radiation in EL4 cells required both protein and RNA synthesis.

• Polymer(Korea)
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• v.25 no.5
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• pp.728-735
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• 2001

In this study, hydrogels from mixtures of chitosan/poly(vinyl alcohol) (PVA) and chitosan/poly(N-vinylpyrrolidone) (PVP) were prepared by ${\gamma}$-ray irradiation, and the mechanical properties such as gelation, water absorptivity and gel strength were examined to evaluate the applicability of these for wound dressing. The PVA : chitosan and PVP : chitosan ratio were in the range of 97:3 ~ 90:10, and the solid concentration of PVA/chitosan and PVP/chitosan solution were 15 wt%. Gamma irradiation with doses of 25, 35, 50, 60 and 70 kGy, was exposed to mixtures of PVA/chitosan and PVP/chitosan to evaluate the effect of irradiation dose. Gel content and gel strength increased as chitosan concentrations in PVA/chitosan and PVP/chitosan decreased, and as irradiation dose increased. Swelling degree increased as chitosan concentrations in PVP/chitosan and PVA/chitosan increased, and as irradiation dose decreased.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1993.11a
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• pp.80-84
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• 1993

In this research, we studied the variation of the dielectric loss absorption of the dielectric loss absorption of the sample according with the change to $\^$60/Co-${\gamma}$-ray irradiation dose of the influence of temperature and applied voltage. In order to investigate the effect of irradiation oriented polypropylene film, we have observed dissipation factor within the temperature range of 30∼130 [$^{\circ}C$] and voltage range of 100∼250$^{\circ}C$ [V]. As for the dependency of temperature by dissipation factor, the ${\alpha}$-peak which appears at high temperature increases accordingly to the increasement of irradiation dose which is contributed by the crystal region and moves towards the high temperature. The ${\beta}$-peak which appears at low temperature is origined from dipoles and molecular motions in the amorphous region. As for the dependency of voltage by tan$\delta$, at low temperature the peak of the tan$\delta$, at low temperature the peak of the tan$\delta$ shifts accordingly to the increasement of irradiation dose towards the high temperature region.

• Journal of Plant Biology
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• v.5 no.1
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• pp.1-6
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• 1962

1) Germination rate was rather irregular than decreasing as increasing dose of radiation and there were no differences between Kyong-Sam and Chuong-Bang of Chinese cabbage. 2) In R1 generation, abnormal leaves from seedling of irradiated seeds were observed. These were more apparent in X-ray irradiation than in thermal neutron. 3) Seedling height was inhibited with increasing dose of X-ray and thermal neutrons. Growth inhibition was more remarkable in X-ray than in thermal neutron. Kyong-Sam demonstrated more sensitivity than Chyong-Bang in both X-ray and thermal neutron. 4) Seedling height produced from seeds subjected to thermal neutrons showed small variation around its mean value, while in X-irradiation there was a greater deviaton from the mean value. 5) Fertility was decreased as increasing with dose, while the frequency of abortive pollen was increased. There were variability of the fertility and frequency of abortive pollen among plants or branches of a plant. 6) The mutants were obtained more in thermal neutron irradiation than in X-ray. The types of mutations obtained in Chinese radish of R2 generation were abnormal leaf, densely glowing leaf, degeneration in growing point and dwarf. The maximum frequency of phenotypic mutations was abnormal leaf mutation.

• Journal of Radiation Industry
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• v.6 no.2
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• pp.171-176
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• 2012

In this study, a crosslinked poly(styrene-butadiene-styrene) [SBS] block copolymers were prepared by using gamma ray irradiation method. The effects of various radiation doses on the degree of crosslinking, thermo property, and morphology of crosslinked SBS block copolymer were investigated. The degree of crosslinking of crosslinked SBS block copolymers were measured by gel-fraction and FT-IR. It was found that the degree of crosslinking of crosslinked SBS block copolymers increases with increase of the irradiation dose while the TGA result shows that the initial degradation temperature of irradiated SBS block copolymer was shifted to lower temperature with increasing irradiation dose. These results indicate that degradation reaction also occurs when SBS block copolymer is exposed to gamma ray irradiation for crosslinking reaction. The SAXS and FE-SEM results indicate that the phase separation of the styrene block and butadiene block was reduced with increasing irradiation dose.