• Proceedings of the KIEE Conference
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• 2009.04a
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• pp.40-42
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• 2009

The economic growth and highly industrialized society have increased the demand for electricity power. As a result, concerns were focused on the energy resource scarcity and global warming. That is why the photovoltaic generation system to address these concerns has been in the spotlight recently. In this thesis, a utility interactive photovoltaic generation system was operated experimentally for the purpose of promoting the spread of the photovoltaic generation system in the future. Also, the effect of the type of array structure has on the performance of the photovoltaic generation system was evaluated quantitatively and by analyzing the comprehensive operating characteristics, the following results were obtained. In the demo system operated for a year, the average irradiation was measured to be 455,076 $[W/m^2]$ and the maximum irradiation to be 626,622 $[W/m^2]$ in May, up 171,546 $[W/m^2]$ or 38[%] compared with the average irradiation. The minimum irradiation was observed to be 294,022$[W/m^2]$ in December, down 161,054 $[W/m^2]$ or 35[%] compared with the average irradiation. The generation power in situation where there is plenty of irradiation was more than the average one, and the generation power in the fixed system amounted to 32[%], the single-axis tracker to 37[%], and the dual-axis tracker to 39[%]. The generation power in situation where there is little irradiation was less than the average one, and the generation power in the dual-axis tracker amounted to 41[%], the single-axis tracker to 40[%], and the fixed system to 36[%].

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.18 no.1
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• pp.31-45
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• 1988

The author studied the histopathologic changes according to a single or a split dose and the time after irradiation on the acinar cells of rat parotid gland. 99 Sprague Dawley rats, weighing about l20gm, were divided into control and 3 experimental groups. In experimental groups, GroupⅠ and Ⅱ were delivered a single dose of l5Gy, 18Gy and Group Ⅲ and Ⅳ were delivered two equal split doses of 9Gy, 10.5Gy for a 4 hours interval, respectively. The experimental groups were delivered by a cobalt-60 teletherapy unit with a dose rate of 222cGy/min, source-skin distance of 50㎝, depth of l㎝ and a field size of l2×5㎝. The animals were sacrificed at 1, 2, 3, 6, 12 hours, 1, 3, 7 days after irradiation and examined by light and electron microscopy. The results were as follows: 1. As the radiation dose increased and the acinar cells delivered a single dose exposure were more damaged, and the change of acinar cells appeared faster than those of a split dose exposure. 2. The histopathologic change of acinar cells appeared at 1 hour after irradiation. The recovery from damaged acinar cells appeared at 1 day after irradiation and there was a tendency that the recovery from damage of a split dose exposure was somewhat later than that of a single dose exposure. 3. Light microscope showed atrophic change of acinar cells and nucleus, degeneration and vesicle formation of cytoplasm, widening of intercellular space and interlobular space. 4. Electron microscope showed loss of nuclear membrane, degeneration of nucleus and nucleoli, clumping of cytoplasm, widening and degeneration of rough endoplasmic reticulum, loss of cristae of mitochondria, lysosome, autophagosome and lipid droplet. 5. Electron microscopically, the change of rough endoplasmic reticulum was the most prominent and this appeared at 1 hour after irradiation as early changes of acinar cells. The nuclear change appeared at 2 hours after irradiation and the loss of cristae of mitochondria was observed at 2 hours after irradiation in all experimental groups.

• Journal of the East Asian Society of Dietary Life
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• v.8 no.4
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• pp.430-440
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• 1998

Meat is a perishable product since it offers favorable conditions for microbial contamination and multiplication. Besides, undercooked and raw meat has been linked to outbreaks of hemorrhagic diarrhea due to the presence of microbial pathogens. Therefore, this study was conducted to find out the effect of the use of gamma-irradiation in order to improve preservation and eliminate this microorganisms. The Initial level of microbial contamination in pork was 1.1$\times$10$^3$ CFU/g (aerobic bacteria), 5.3$\times$10$^3$CFU/g (psychrophile), 3.1$\times$10$^3$ CFU/g (coliforms) and 3.2$\times$10$^3$ CFU/g(Listeria), All kinds of contaminated microorgnisms were sterilized by gamma irradiation at 3 kGy. The proximate composition of pork was not significantly changed by irradiation dose and storage period. The pH was slightly increased during storage period and titratable acidity decreased. However, no significant changes in pH and acidity were observed by gamma irradiation. There was no difference in total amino acid content regardless of irradiation dose and storage period. Glutamic acid was detected at high levels throughout the storage period. The major mineral compositions of pork were potassium, phosphorus, sodium, magnesium. No significant difference in the components of minerals were observed by gamma irradiation.

• Korean Journal of Veterinary Research
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• v.42 no.2
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• pp.183-190
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• 2002

The effects of ionizing radiation on the peripheral blood elements of ICR mouse were examined after varying doses of whole-body gamma-irradiation. ICR mice (n=50) were exposed to 0, 2, 4, 6 and 8 Gy gamma-ray ($^{60}Co$) at 10 Gy/min. The animals were studied for their hematological response on days, 3, 7, 14, 21, 42 and 56 post irradiation. No significant change was noted in erythrocyte, hemoglobin and hematocrit values after irradiation with dose of 2 Gy. Decreasing erythrocyte, hemglobin and hematocrit values occured after irradiation with doses of more than 4 Gy on day 7 after irradiation followed by a sharp fall on day 14. A recovery in these values was noted after 3 weeks of irradiation. Thrombocyte counts decreased on day 3, reaching minimal values on day 7. The total number of leukocytes was reduced on day 3, mainly because of a decrease in the lymphocyte population. An evident lymphopenia and neutropenia occur almost on the day 3 and last up to the day 28 after irradiation. All of the hematological values decreased in the blood in a dose-dependent manner at the same time.

• Food Science of Animal Resources
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• v.31 no.3
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• pp.366-371
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• 2011

Viscosity is critically important for bulgogi sauce. However, exposure to irradiation may decrease the rheological properties of bulgogi sauce. This study was conducted to compare the effects of gamma irradiation (0-9 kGy) on viscosity, molecular weight, pH, reducing end level, and water solubility of xanthan gum, guar gum, and locust bean gum as thickening agents/stabilizers in bulgogi sauce. The physicochemical properties of all samples changed (p<0.05) from 3965 to 0 cP (viscosity), from 6048 to 28 kDa (molecular weight), from 5.79 to 4.62 (pH), from 0.13 mg/mL to 1.72 mg/mL (reducing end level), and from 6% to 87% (water solubility) following gamma irradiation. Viscosity after irradiation was most stable (p<0.05) in xanthan gum (from 1249 to 92 cP) compared with guar gum (from 3965 to 0 cP) and locust bean gum (from 1631 to 0 cP). The sensory properties (texture and taste) of bulgogi sauce prepared with xanthan gum (1%, w/w) were highly maintained (about 7.0-5.0) after high-dose irradiation of up to 40 kGy. These results indicate that xanthan gum can be effectively used as a thickening agent/stabilizer in bulgogi sauce, which had low viscosity after irradiation.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.4
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• pp.596-602
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• 2013

To investigate the synergistic effect(s) of electron-beam (EB) irradiation and leek (Allium tuberosum Rottler) extract on the quality of pork jerky during ambient storage, we irradiated prepared pork jerky samples (control and samples with 0.5% and 1.0% leek extract) with EB technology at doses of 0, 1, 2, and 4 kGy, stored them for 2 months at $25^{\circ}C$, and analyzed them. Water activity was 0.73 to 0.77 in non-irradiated samples, and no significant difference in the water activity was observed between the samples treated with leek and the control. The total aerobic bacterial count was significantly decreased with an increase in the irradiation dose and leek extract addition when compared to that of the control ($4.54{\pm}0.05$ log CFU/g). Further, the Hunter color values ($L^*$, $a^*$, and $b^*$) were found to be significantly decreased following leek extract addition and EB irradiation. However, the color values, especially the $a^*$ value of the irradiated samples significantly increased during storage. Notably, increasing the EB irradiation dose enhanced the peroxide value. Sensory evaluation revealed that irradiation decreased flavor and overall acceptability. Our findings suggest the use of EB irradiation in combination with leek extract to improve the microbiological safety of pork jerky. However, in order to meet market requirements, novel methods to enhance the sensory quality of pork jerky are warranted.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.4
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• pp.1993-1998
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• 2016

The effects of carbon-ion irradiation on cancer cell telomere function have not been comprehensively studied. In our previous report cancer cells with telomere dysfunction were more sensitive to carbon-ion irradiation, but the underlying mechanisms remained unclear. Here we found that telomerase activity was suppressed by carbon-ion irradiation via hTERT down-regulation. Inhibition of telomere activity by MST-312 further increased cancer cell radiosensitivity to carbon-ion radiation. hTERT suppression caused by either carbon-ion irradiation or MST-312 impaired mitochondrial function, as indicated by decreased membrane potential, mtDNA copy number, mitochondrial mass, total ATP levels and elevated reactive oxygen species (ROS). PGC-$1{\alpha}$ expression was repressed after carbion-ion irradiation, and hTERT inhibition by MST-312 could further exacerbate this effect. Lowering the mitochondrial ROS level by MitoTEMPO could partially counteract the induction of cellular senescence induced by carbon-ion radiation and MST-312 incubation. Taken together, the current data suggest that telomere-mitochondrion links play a role in the induction of senescence in MCF-7 cells after carbon-ion irradiation.

• Journal of Korean Neurosurgical Society
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• v.37 no.1
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• pp.48-53
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• 2005

Objective: The purpose of this study is to elucidate in vitro responses to combined gamma knife irradiation and p53 gene transfection on human malignant glioma cell lines. Methods: Two malignant human glioma cell lines, U87MG (p53-wild type) and U373MG (p53-mutant) were transfected with an adenoviral vector containing p53 (MOI of 50) before and after applying 20Gy of gamma irradiation. Various assessments were performed, including, cell viability by MTT assay; apoptosis by annexin assay; and cell cycle by flow cytometry, for the seven groups: mock, p53 only, gamma knife (GK) only, GK after LacZ, LacZ after GK, GK after p53, p53 after GK. Results: Cell survival decreased especially, in the subgroup transfected with p53 after gamma irradiation. Apoptosis tended to increase in p53 transfected U373 MG after gamma irradiation (apoptotic rate, 38.9%). The G2-M phase cell cycle arrest markedly increased by transfecting with p53, 48 hours after gamma knife irradiation in U373 MG (G2-M phase, 90.8%). Conclusion: These results suggest that the in vitro effects of combined gamma knife irradiation and p53 gene transfection is an augmentation of apoptosis and G2-M phase cell cycle arrest, which are more exaggerated in U373 MG with p53 transfection after gamma knife irradiation.

• Nutrition Research and Practice
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• v.8 no.4
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• pp.398-403
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• 2014

BACKGROUND/OBJECTIVES: Ultraviolet B (UVB) irradiation on skin can induce production of reactive oxygen species (ROS), which cause expression of matrix metalloproteinases (MMPs) and collagen degradation. Thus, chronic exposure of skin to UVB irradiation leads to histological changes consistent with aging, such as wrinkling, abnormal pigmentation, and loss of elasticity. We investigated the protective effect of the standardized green tea seed extract (GSE) on UVB-induced skin photoaging in hairless mice. MATERIALS/METHODS: Skin photoaging was induced by UVB irradiation on the back of Skh-1 hairless mice three times per week and UVB irradiation was performed for 10 weeks. Mice were divided into six groups; normal control, UVB irradiated control group, positive control (UVB + dietary supplement of vitamin C 100 mg/kg), GSE 10 mg/kg (UVB + dietary supplement of GSE 10 mg/kg), GSE 100 mg/kg (UVB + dietary supplement of GSE 100 mg/kg), and GSE 200 mg/kg (UVB + dietary supplement of GSE 200 mg/kg). RESULTS: The dietary supplement GSE attenuated UVB irradiation-induced wrinkle formation and the decrease in density of dermal collagen fiber. In addition, results of the antioxidant analysis showed that GSE induced a significant increase in antioxidant enzyme activity compared with the UVB irradiation control group. Dietary supplementation with GSE 200 mg/kg resulted in a significant decrease in expression of MMP-1, MMP-3, and MMP-9 and an increase in expression of TIMP and type-1 collagen. CONCLUSIONS: Findings of this study suggest that dietary supplement GSE could be useful in attenuation of UVB irradiation-induced skin photoaging and wrinkle formation due to regulation of antioxidant defense systems and MMPs expression.

• Korean Journal of Food Science and Technology
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• v.31 no.3
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• pp.665-671
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• 1999

Post mortem bovine muscle. semitendinosus was used to investigate the effects of gamma irradiation on physicochemical properties. The muscle was cut into pieces of 2 cm in thickness and packaged with 2 different methods; vacuum-packaged and air-packaged. The packaged samples were irradiated at designated doses of 0, 1, 3 and 5 kGy by Cobalt-60 irradiator. Muscle protein solubility, purge loss, composition and contents of free amino acids, and shear force were observed during storage at $4^{\circ}C$. We found no significant differences in the purge loss and the contents of free amino acids. Muscle protein solubility slightly increased depending upon the increase of the dose. The decrease of shear force by gamma irradiation was observed. Therefore, it is considered that meat quality can be improved by gamma irradiation.