• Food Science and Biotechnology
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• 제16권1호
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• pp.138-141
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• 2007

The aim of this study was to investigate the effect of irradiation treatment on the inactivation of pathogens in ready-to-use cooked carrot. The pathogens tested were Salmonella typhimurium, Escherichia coli, Staphylococcus aureus, and Listeria inocua. Following the inoculation of these organisms into cooked carrot (about $10^6-10^8\;CFU/g$), the growth of each was inhibited due to irradiation for 24 hr of storage at $20^{\circ}C$. S. typhimurium and E. coli inoculated into cooked carrot were not detected following irradiation with 3 kGy. S. aureus and L. inocua inoculated into the cooked carrot decreased by 5 logs (CFU/g) following 2 kGy irradiation. The range of $D_{10}$ values was from 0.30-0.50. The Hunter color, $L^*-,\;a^*-$, and $b^*-values$, and the hardness of the cooked carrot were not effected by irradiation treatment. The sensory score of irradiated cooked carrot was not statistically different from that of non-irradiated samples (p>0.05). These results indicate that low dose irradiation can enhance the microbial safety and extend the shelf-life of ready-to-eat foods such as cooked carrot.

• 방사선산업학회지
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• 제6권1호
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• pp.55-59
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• 2012

Polyacrylonitrile (PAN)-based carbon fibers have been widely used due to their unique chemical, electrical, and mechanical properties. Electron beam irradiation has been extensively employed as means of altering properties of polymeric materials. Electron beam irradiation can induce chemical reactions in materials without any catalyst. Electron beam irradiation may be useful in accelerating the thermal compression stabilization of PAN nanofibers. To investigate the irradiation effect on PAN fibers, PAN nanofibers were irradiated by electron beam at 1,000~5,000 kGy. Irradiated and non-irradiated PAN nanofibers were heated at 180 and $220^{\circ}C$ without applying pressure for 15 min. Then 1 metric ton has been applied for 5 min. SEM images have been found that the fiber kept its morphological behavior after the hot pressing up to electron beam irradiated 1,000 kGy. DSC thermograms showed that the peak temperatures of the exothermic reactions were found to decrease with increasing electron beam irradiation doses and temperature. FT-IR spectra have been found to decrease $C{\equiv}N$ stretch band with increasing the electron beam irradiation dose. These results indicate that the modification of PAN via reactions such as cyclization is significantly enhanced by electron beam irradiation and thermal compression technique.

• 한국식품저장유통학회지
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• 제16권4호
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• pp.590-593
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• 2009

감마선 조사가 미역의 저장성 개선에 미치는 영향을 평가하였다. 미생물 오염도 평가 결과 3 kGy 이하의 선량에서 미생물이 검출되지 않았다. 2주 저장한 후, 조사처리 하지 않은 미역의 미생물이 6 log CFU/g이 증가하였다. 그러나 5 kGy 조사 처리한 미역의 경우 미생물이 검출되지 않았다. 5 kGy의 감마선 조사를 적용하였을 때, 미역의 명도 값이 소폭 증가하였다. 미역의 경도 측정 결과 3 kGy 이하의 감마선 조사에 의해 영향을 미치지 않았으며, 저장기간에 따른 차이는 없는 것으로 나타났다. 이상의 결과를 종합하여 볼 때, 3 kGy 감마선 조사는 미역의 품질에 영향을 받지 않고, 저장성을 연장시킬 수 있는 효과적인 기술이라고 판단된다.

• 치과방사선
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• 제25권1호
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• pp.71-87
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• 1995

The purpose of this study was to investigate the early irradiation changes on the ultrastructure of the capillary endothelial cell in the rat submandibular glands. For the study, 110 Sprague-Dawley strain male rats were singly irradiated to their neck regions with the doses of 2Gy, 5Gy, and 10Gy by 6MV X -irradiation, and sacrificed on the 3 hours, 6 hours, 12 hours, 1 day, 3 days, 7 days, and 14 days after irradiation. The authors observed the histologic and ultrastructural changes of the capillary endothelial cell using the light and electron microscopes. The results were as follows: I. In the light microscopic examination, the capillary dilation was observed on the 6 hours group and the capillary density was slightly increased on the 12 hours group after 2Gy and 5Gy irradiation. And luminal size and capillary density were decreased on the 3 days and the 7 days groups after irradiation, after then, they were recovered. But capillary density was still decreased on the 14 days group after 10Gy irradiation. 2. In the transmission electron microscopic examination, the mild proliferation of cytoplasmic process of the endothelial cell and reduction in luminal size were observed on the 3 hours group after irradiation. After then, endothelial swelling, marked proliferation of cytoplasmic process, thickened basal lamina, and numerous pinocytotic vesicles were observed after the 1 day group after irradiation. Thickened basal lamina and numerous pinocytotic vesicles were still observed until the 7 days group after irradiation. These changes were recovered to normal on the 14 days group after 2Gy and 5Gy irradiation, but not after 10Gy irradiation. 3. In the scanning electron microscopic examination, the dilation of conduits and constriction, and meandering were observed on the 1 day group after 10Gy irradiation. These changes were observed with increased coarseness of the surface of the vascular resin casting on the 3 days group after irradiation. 4. From the above results, endothelial swelling, proliferation of cytoplasmic process, and thickening of the basal lamina appeared before the 6 hours group after irradiation. And these changes may also induce the increase of the capillary number and luminal size, after then, capillary permeability was increased via the increase of the number of pinocytotic vesicles. The changes were observed earlier and more apparent with the increase of the irradiation doses under the dose of 10Gy irradiation.

• 한국대기환경학회지
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• 제17권1호
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• pp.97-104
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• 2001

Decomposition of trichloroethlyene(TCE) in electron beam irradiation was examined on order to obtain information on the treatment of VOC in air. Air containing vaporized TCE has been studied in a flow reactor with different reaction environments, at various initial TCE concentration and in the presence and absence of water vapor. Maximum decomposition was observed in oxygen reaction environment and the degree of decomposition was about 99% at 20kGy for 2,000ppm initial TCE. The concentration of TCE exponentially decreased with dose in air and pure oxygen. The effect of water vapor on TCE decomposition efficiency was examined. The decomposition rate of TCE in the presence of water vapor (5,600 ppm) was approximately 10% higher than that in the absence of water vapor. Dichloroacetic acid, dichloroacethyl chloride and dichloroethyl ester acid were identified as primary products of this reaction adn were decomposed and oxidized to yield CO and $CO_2$. Perchloroethylene, hexachloroethane, chloroform and carbon tetrachloride were also observed as highly chlorinat-ed by products.

• 한국식품위생안전성학회지
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• 제11권3호
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• pp.197-201
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• 1996

D10 values obtained for radiation alone in Bacillus subtilis and Clostridium perfrigenes were 0.35-0.48 kGy in vegetative cells, and 2~2.08 kGy in spores, respectively. Irradiation dose of 24 kGy completely inhibited spores. In the case of heat treatment, D50, 60 values ranged from 10 to 14 minutes in vegetative cells, and D70, 80, 90 values ranged from 10 to 140 minutes in spores. In the case of combined treatment with heat and radiation, D10 values ranged form 1 to 1.25 kGy in vegetative cells, and from 3.42 to 3.61 kGy in spores. Thus, resistance of cells to gamma radiation did not seem to be influences by pre-heating.

• 대한방사선치료학회지
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• 제2권1호
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• pp.75-80
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• 1987

Intraoperative Radiation therapy (IORT) is a cancer treatment modality in which resectable masses or organs are removed surgically and residual cancer calls are sterilized by irradiation with a single massive dose during while patient is still anesthetized. Because it is possible that the turner mass can be visualized directly at the time of surgical exploration, tumor volume can be determined more precisely and at the same tin e sensitive adjacent structures can be pulled aside from the irradiation. With these theoretical advantages as compare to conventional external irradiation, IORT can improve the therapeutic ratio of tumor control to normal tissue injury. Yonsei cancer center initiated a pilot study of multidisciplinary IORT program in february of 1986 for the fist attempt in Korea. IORT Was performed in 7 patients with stomach cancer by using existing NELAC-1018 Linear Accelerator treatment room as a surgical suite. IOTR team included department of surgery, Department of Anethesiology, Department of Clinical pathology, operating room nursing personal and Department of radiation oncology.

• Journal of Ginseng Research
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• 제8권1호
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• pp.38-44
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• 1984

In order to investigate the influence of gamma-irradiation on fatty acids in ginseng, ginseng were irradiated with various radiation doses(0-50 Mrads). The results are as follows. 1. With increasing dose, standard fatty acids were decreased in the order of linolenic acid, linoleic acid and oleic acid, and their contents in the presence of oxygen were decreased more t than that in the absence of oxygen. 2. Changes of lipid content in white ginseng by gamma irradiation were varied with the samples, but the changes of crude lipid and purified lipid in a sample were showed same fashion. 3. The fatty acid contents in white ginseng were decreased by gamma irradiation in the order of linolenic acid, linoleic acid, oleic acid, stearic acid and palmitic acid.

• Journal of Magnetics
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• 제20권3호
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• pp.241-245
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• 2015

A study on the preparation of nickel oxide nanoparticles using electron beam irradiation is described. Nickel nanoparticles were synthesized with nickel chloride hexahydrate as a metal precursor and different sodium hydroxide concentrations using electron beam irradiation. The effects of sodium hydroxide concentration and electron beam absorbed doses were investigated. The samples were synthesized at different sodium hydroxide concentrations and with absorbed doses of 100 to 500 kGy at room temperature. Synthesized nanoparticles were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) and a vibrating sample magnetometer (VSM). The nanoparticle morphologies seemed to be non-spherical and aggregated. The 1:1 molar ratio of nickel chloride hexahydrate and sodium hydroxide showed a higher purity and saturation magnetization value of 13.0 emu/g. The electron beam absorbed dose was increased with increasing nickel nanoparticle nucleation.

• 한국환경보건학회지
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• 제16권1호
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• pp.55-65
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• 1990

This study was carried out to investigate the effects on sister chromatid exchanges (SCEs) and chromosome aberrations in PHA or LPS stimulated mouse spleen and bone marrow lymphocytes after an acute whole body irradiation. Frequencies of sister chromatid exchanges were significantly increased with the increased dose(from zero to 400tad) but there was no differences between B-cell and T-cell. By times, the maximum induced SCE levels was observed at 12 hours after irradiation and then returned to base level at one day in 100rad group and three day in 400rad group. There was a significant difference in chromosome aberration with increasing exposure. X-ray irradiated chromosome aberration was long lived relative to SCE. This results show that counting the incidence of SCE may not provide a sensitive system for detecting X-ray exposure.