• Korean Journal of Veterinary Research
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• v.15 no.1
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• pp.9-13
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• 1975

In oder to investigate the effects of cobalt-60 gamma irradiation on the postnatal body gains and the other influece of the pregnant mice were subjected to single whole-body gamma irradiation externally. The results obtained were as follows: 1. The all mice of 400, 600, and 800 Rads gamma-irradiated groups showed abortion after prenatal gamma irradiation within 4 to 9 days. 2. There were significant differences of the postnatal body gains of mice between the control and treated groups (100 Rads and 200 Rads gamma irradiation). 3. The relation between gamma-irradiated doses and the postnatal growth rates of mice were inversly proportional.

• Journal of Digital Convergence
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• v.14 no.11
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• pp.639-644
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• 2016

The purpose of this study is to determine the effect of the light-emitting-diode (LED) to investigate proliferation of human epidermal keratinocyte and collagen, procollagen expression. In order to determine whether LED irradiation can safely be applied to human skin, the proliferative effects of LED irradiation were determined by MTS assay in Human Epidermal Keratinocytes. Wavelength of 470nm LED irradiation increased mRNA expression of collagen, procollagen without cytotoxity. Our results suggest that 470nm LED irradiation may have a proliferative effects and collagen synthesis property. In order to determine whether LED irradiation can safely be applied to human skin, the cytotoxic effects of LED irradiation were determined by MTS assay in Human Dermal Fibroblasts (HDF). As far as we know, this is the first report demonstrating in vitro collagen synthesis activity of 470nm LED irradiation and being a scientific basis for the cosmetic.

• Food Science and Biotechnology
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• v.16 no.5
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• pp.832-835
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• 2007

Moisture content of normal, waxy, and high amylose com starches was adjusted to 10-35%, and irradiated in a microwave oven. The effect of microwave irradiation on the crystalline structure of starch was measured by using a differential scanning calorimetry (DSC), and X-ray diffractometry. Pasting viscosity profile was also determined by using a rapid viscoanalyzer (RVA). For all the 3 types of starches tested, the rate of temperature increase by the microwave irradiation was faster and more rapidly reached the maximum temperature of the pressure bomb ($120^{\circ}C$) when the moisture content was higher. X-ray diffraction and DSC data revealed that the microwave irradiated starch underwent partial disruption of crystalline structure. RVA studies showed that the irradiation caused significant reductions in maximal viscosity and breakdown, whereas pasting temperature was increased. Overall trends revealed that the microwave irradiation on the starch containing limited moisture content (less than 35%) provided the effects similar to the heat moisture treatment. These effects became more significant when the moisture content was higher. Compared to waxy com starch, normal, and high amylose com starches appeared to be more susceptible to the microwave irradiation.

• Korean Journal of Veterinary Research
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• v.43 no.4
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• pp.633-639
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• 2003

We investigated the effect of green tea and its fractions of alcohol and polysaccharide on jejunal crypt survival, endogenous spleen colony formation, and apoptosis in jejunal crypt cells of mice irradiated with high and low dose of gamma-irradiation. Jejunal crypts were protected by pretreatment of green tea (i.p.: 50 mg/kg of body weight, at 12 and 36 hours before irradiation., p.o.: 1.25% water extract, for 7days before irradiation, p<0.01) and alcohol and polysaccharide fractions showed no significant modifying effects. Green tea and its fractions administration before irradiation (i.p. at 12 and 36hours before irradiation) resulted in an increase of the formation of endogenous spleen colony (p<0.05). The frequency of radiation-induced apoptosis in intestinal crypt cells was also reduced by pretreatment of green tea (i.p. at 12 and 36 hours before irradiation, p<0.05., p.o. for 7days before irradiation, p<0.001) and its fractions (p<0.001). These results indicated that green tea might be a useful radioprotector, especially since it is a relatively nontoxic natural product. Further studies are needed to characterize better the promotion nature of green tea and its components.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.5
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• pp.1051-1057
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• 1999

The effects of gamma irradiation on taste compounds of low salted and fermented squid were investig ated. Salted and fermented squid products were prepared with salt concentrations of 5%, 10%, and 20% and was fermented at 15oC and 25oC after gamma irradiation with a dosage of 2.5~10 kGy. Amino nitrogen (AN), volatile basic nitrogen(VBN), trimethylamine(TMA), and hypoxanthine(Hx) contents were examined during the fermentation periods. Results showed that gamma irradiation had no effect on the initial con tents of AN, VBN, TMA, and Hx compared with non irradiated salted and fermented squid. During the fermentation periods, these contents rapidly increased in accordance with the decrease in NaCl concen tration and irradiation dose, and the increase in fermentation temperature. Specifically, the taste compounds of salted and fermented squid prepared with a NaCl concentration of 10% and an irradiation dose of 10 kGy maintained the appropriate level for the fermentation period at 15oC.

• Imaging Science in Dentistry
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• v.34 no.3
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• pp.137-144
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• 2004

Purpose: To investigate the effects of low dose irradiation on the calcium content and calcific nodule formation of the MC3T3-El osteoblastic cell line. Materials and Methods: Cells were irradiated with a single dose of 0.2, 0.4 and 0.6 Gy at a dose rate of 5.38 Gy/min using Cs-137 irradiator. After irradiation, the calcium content and calcific nodule formation were examined on the 1st, 2nd, 3rd and 4th week. Results: We did not find any significant difference of total calcium content after irradiation of 0.2, 0.4 and 0.6 Gy when compared with the unirradiated control group. There was no significant difference of total calcium content between 0.2, 0.4 and 0.6 Gy irradiated groups. We found an increased tendency of the calcific nodule formation after irradiation of 0.2, 0.4 and 0.6 Gy when compared with the unirradiated control group without significant difference of calcific nodule formation between 0.2, 0.4 and 0.6 Gy irradiated groups. Conclusion : The results showed an increased tendency of the calcific nodule formation after low dose irradiation. However, this tendency did not increase with the increase of irradiation dose.

• Journal of Semiconductor Engineering
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• v.2 no.1
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• pp.119-124
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• 2021

Along with the needs for feasibility in the field of space applications, interests in radiation-hardened electronics is growing rapidly. Gallium nitride (GaN)-based devices have been widely researched so far owing to superb radiation resistance. Among them, research on the most abundant protons in low earth orbit (LEO) is essential. In this paper, proton irradiation effects on parameter changes, degradation mechanism, and correlation with reliability of GaN-based devices are summarized.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.28 no.1
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• pp.87-109
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• 1998

The present study was designed to elucidate the effects of the Co-60 γ irradiation and/or calcium­deficient diet on the dentin and cementum formation of rat molar. The pregnant three-week old Sprague­Dawley rats were used for the study. The experimental group was divided into two groups, irradiation/normal diet group and irradiation/calcium-deficient diet group. The control group was non­irradiation/normal diet group. The abdomen of the rats at the 19th day of pregnancy were irradiated with single absorbed dose of 350cGy. The rat pups were sacrificed on the 14th day after delivery and the maxillae including molar tooth germ were taken. The specimens including the 1st molar tooth germ were prepared to make tissue sections for light and transmission electron microscopy. Some of tissue sections for light microscopy were stained immunohistochemically with anti-fibronectin antibody. The results were as follows; 1. The Hertwig's epithelial root sheath cells, which are related to the differentiation of the tooth-forming cells, showed irregular cellular arrangement, decrease of intercellular junctional complex, and decreased immunoreactivity to the fibronectin after irradiation. These were more severe in the irradiation/calcium-deficient diet group. 2. The cementoblasts at the cementum-forming area showed chromatin clumpings after irradiation. The immu noreactivity to the fibronectin was weaken after irradiation, especially irradiation/calcium-deficient diet group. 3. The odontoblasts at the dentin-forming area showed increase of lysosomes in the cytoplasm and destruction of intercellular junctional complex. The irradiation/calcium-deficient diet group showed decrease of number and density of the electron dense particles and a large number of vacuoles scattered in the dentin matrix. The immunoreactivity was weaken.

• The Plant Pathology Journal
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• v.32 no.5
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• pp.460-468
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• 2016

To study the control of postharvest decay caused by Colletotrichum gloeosporioides and Penicillium expansum, gamma irradiation alone or in combination with fumigation was evaluated to extend the shelf life of apples in South Korea. An irradiation dose of 2.0 kGy resulted in the maximum inhibition of C. gloeosporioides and P. expansum spore germination. The gamma irradiation dose required to reduce the spore germination by 90% was 0.22 and 0.35 kGy for C. gloeosporioides and P. expansum, respectively. Microscopic observations revealed that when the fungal spores were treated with gamma irradiation (4.0 kGy), conidial germination was stopped completely resulting in no germ tube formation in C. gloeosporioides. Treatment with the eco-friendly fumigant ethanedinitrile had a greater antifungal activity against C. gloeosporioides and P. expansum in comparison with the non-treated control under in vitro conditions. The in vitro antifungal effects of the gamma irradiation and fumigation treatments allowed us to further study the effects of the combined treatments to control postharvest decay on stored apples. Interestingly, when apples were treated with gamma irradiation in combined with fumigation, disease inhibition increased more at lower (< 0.4 kGy) than at higher doses of irradiation, suggesting that combined treatments reduced the necessary irradiation dose in phytosanitary irradiation processing under storage conditions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.6
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• pp.864-869
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• 2003

In order to expand the acceptability of irradiated foods by public, substantial basic data about the change of nutrient contents during irradiation are needed. The nutrient contents and digestibility of macronutrients such as carbohydrates, proteins and lipids in foods are known to be not significantly influenced by irradiation treatment. However, some of the vitamins among micronutrients are susceptible to irradiation to a large extent depending upon the food composition, food process and storage condition. This study was conducted to investigate change of thiamin in chicken breast, and vitamin C in strawberry and mandarine orange after irradiation. The effects of irradiation at frozen or refrigerated state and the effects of cooking such as heating or micron ave on thiamin contents in chicken breast were observed. Irradiation reduced the thiamin content, however, temperature condition during irradiation was much more important factor to the loss of thiamin contents. In strawberry, vitamin C content was significantly affected by original content or the variety rattler than treatments such as irradiation, heating or microwave. These results indicated that the losses of water-soluble vitamins, especially thiamin or vitamin C, are affected by food temperature during irradiation process and variety or composition of foods rallier than irradiation itself, within an acceptable range of irradiation.