• BMB Reports
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• v.33 no.2
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• pp.133-137
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• 2000

To elucidate the effect of oxygen radicals on the molecular properties of proteins, the secondary and tertiary structure and molecular weight size of BSA and ${\beta}$-lactoglobulin were examined after irradiation of proteins at various doses. Gamma-irradiation of protein solutions caused the disruption of the ordered structure of protein molecules as well as degradation, cross-linking, and aggregation of the polypeptide chains. As a model system, BSA and ${\beta}$-lactoglobulin were used as a typical ${\alpha}$-helical and a ${\beta}$-sheet structure protein, respectively. A circular dichroism study showed that the increase of radiation decreased the ordered structure of proteins with a concurrent increase of aperiodic structure content. Fluorescence spectroscopy indicated that irradiation quenched the emission intensity excited at 280 nm. SDS-PAGE and a gel permeation chromatography study indicated that radiation caused initial fragmentation of proteins resulting in a subsequent aggregation due to cross-linking of protein molecules.

• Radiation Oncology Journal
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• v.2 no.2
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• pp.173-175
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• 1984

The therapeutic effect of mammary breast cancer of rat (Sprague Dawley) was estimated by single and 5 fractionated irradiation of $Co^{60}-\gamma-ray$. Response rates over 50a were 20, 43, 67, $80\%$ respectively by single dose irradiation of 800, 1,200, 1,600, 2,000 rad, and 20,38, 57, $88\%$ by 5 fractionated irradiation of 1,400, 2,100, 2,800, 3,500 rad. $50\%$ tumor control dose$(TCD_{50})$ were 1,282rad, 2,312rad respectively with single and fractionated irradiation.

• Food Science and Industry
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• v.53 no.3
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• pp.264-276
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• 2020

Ionizing radiation is one of the efficient non-thermal pasteurization methods. The US Food and Drug Administration (FDA) allows the use of ionizing radiation to a dose up to 10 kGy for controlling foodborne pathogens and extending the self-life of foods. Recently X-rays, generated on absorption of high energy electrons in an appropriate metal target, have been used commercially for sterilization purposes. X-rays have the advantages of higher penetration power than E-beams and absence of harmful radioactive sources, such as Cobalt-60 or Cesium-137 associated with gamma-rays. That is why it has continued to receive attention as an attractive alternative to gamma-ray or E-beam irradiation. In this article, the potential of X-ray irradiation for controlling foodborne pathogens in various food products and necessary pre-requisite knowledge for the introduction of X-ray irradiation to the Korean food industry will be provided.

• Journal of Radiation Industry
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• v.2 no.1
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• pp.43-51
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• 2008

Radiation technology is currently used in a number of industrial processes such as sterilization, cross linking of polymer, food irradiation, rubber vulcanization in the tire manufacturing, contaminated medical waste, etc. Gamma ray and electron beam are the key examples of well-established economical applications of radiation processes. The purpose of this paper is to review the recent technological trends and activities for radiation processes in order for the industrial end users to better understand, and obtain useful information about the technology. It is clear that the radiation processing technology has potential for a variety of the industrial applications.

• Preventive Nutrition and Food Science
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• v.8 no.2
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• pp.191-195
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• 2003

We investigated the effects of gamma irradiation on the microbiological, chemical and sensory qualities of bulgogi, a traditional Korean meat product. Gamma irradiation reduced the number of coliform bacteria and bacterial colonies counted in Salmonella-Shigella selective agar to a non-detectable level. Thermophillic microorganisms (mainly Bacillus spp.) in bolgogi refrigerated for 20 days were also significantly reduced by 3 log cycles by 2.5 to 7.5 kGy of irradiation, compared to the control. Electron donating ability and shear force of ready-to-cook bulgogi was not significantly affected by gamma irradiation. Irradiation increased the 2-thiobarbituric acid reactive substances (TBARS) value. The irradiated, raw, ready-to-cook bulgogi had significantly higher scores in color and appearance than those of non-irradiated controls from sensory evaluation. The overall acceptance of cooked bulgogi had higher scores in non-irradiated or 2.5 kGy-irradiated bulgogi than the 5.0- or 7.5-kGy irradiated counterparts. In conclusion, irradiation at 2.5 kGy is recommended as a method to improve shelf-life, safety, and to achieve acceptable quality of ready-to-cook bulgogi without any adverse changes in the sensory characteristics.

• Radiation Oncology Journal
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• v.2 no.2
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• pp.261-270
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• 1984

The intrauterine irradiation is essential to achieve adequate tumor dose to central tumor mass of uterine malignancy in radiotherapy. The complications of pelvic organ are known to be directly related to radiation dose and physical parameters. The simulation radiation and medical records of 203 patients who were treated with intrauterine irradiation from Feb. 1983 to Oct. 1983, were critically analized. The physical parameters to include distances between lateral walls of vaginal fornices, longitudinal and lateral angles of tandem applicator to the body axis, the distance from the external os of uterine cervix to the central axis of ovoids were measured for low dose rate irradiation system and high dose rate remote control afterloading system. The radiation doses and dose distributions within cervical area including interesting points and bladder, rectum, according to sources arrangement and location of applicator, were estimated with personal computer. Followings were summary of study results ; 1. In distances between lateral walls of vaginal fornices, the low dose rate system showed as $4\~7cm$ width and high dose rate system showed as $5\~6cm$. 2. In horizontal angulation of tandem to body axis, the low dose rate system revealed mid position$64.6\%$, left deviation $19.2\%$and right deviation $16.2\%$. 3. In longitudinal angulation of tandem to body axis, the mid position was $11.8\%$ and anterior angulation $88.2\%$ in low dose rate system but in high dose rate system, anterior angulation was $98.5\%$. 4. Down ward displacement of ovoids below external os was only $3\%$ in low dose rate system and $66.7\%$ in high dose rate system. 5. In radiation source arrangement, the most activities of tandem and ovoid were 35 by 30 in low dose rate system but 50 by 40 in high dose rate system. 6. In low and high dose rate system, the total doses an4 TDF were 50, 70 Gy and 141, 123, including 40 Gy external irradiation. 7. The doses and TDF in interesting points Co, B, were 93, 47 Gy and 230, 73 in high dose rate system but in low doss rate system, 123, 52 Gy and 262, 75 respectively. 8. Doses and TDF in bladder and rectum were 70, 68 Gy and 124, 120 in low dose rate system, but in high dose rate system, 58, 64 Gy 98, 110 respectively, and then grades of injuries in bladder and rectum were 25, $30\%$ and 18, $23\%$ respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.3
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• pp.296-301
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• 1999

The concerns on the crop damage by ultraviolet (UV) radiations is increasing owing to the decrease of their absorbing stratospheric ozone in the tropospheric. Cultivar differences on early growth of UV radiation among five Korean rice cultivars, four japonica types and one Tongil type (indica-japonica cross hybrid), were studied. Pot-seeded rice plants were grown under four different radiation conditions, i.e., visible radiation only, visible radiation with supplemented with high or low dose of UV-B (280~320 nm in wavelength) and UV-C (less than 280 nm in wavelength). The inhibitory degree on plant height, shoot and root weight and length of leaf blade and leaf sheath were determined at 40 days after seeding. UV-C showed the most severe inhibitory effect on the degree of biomass gain and leaf growth in most cultivars examined, followed by high UV-B and low UV-B. Among the cultivars used, the Kuemobyeo was the most sensitive cultivar and had not repair or showed resistance ability to continued irradiation of UV radiation. However, Janganbyeo and Jaekeon showed different responses that the elongation of leaf blades was promoted on 2nd and 3rd leaves and inhibited on 4th and 5th leaves but this inhibitory degree was reduced on 6 th and 7th leaves. Such tendency on leaf growth means that both cultivars had low sensitivity and most resistant ability to continued irradiation of UV radiation. While Tongil showed different response to enhanced UV radiation, ie., low UV-B promoted leaf growth but the inhibitory was severely increased by continued irradiation of high UV-B and UV-C, which means that Tongil had high threshold of UV radiation for response as an inhibitory light of plant growth. The results of this study indicate that the differences on sensitivity or resistant to the effects of UV radiation were existed among Korean rice cultivars.

• Polymer(Korea)
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• v.33 no.3
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• pp.268-271
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• 2009

In this study, the distribution behaviors of the polystyrene sulfonic acid (PSSA) grafting polymer across the FEP-g-PSSA membranes prepared by a simultaneous irradiation method, were investigated by analyzing the cross-section of the membranes with a SEM-EDX instrument. The effects of irradiation conditions such as the degree of grafting, FEP film thickness, and grafting solvent on the distribution of the grafting polymer were mainly studied in this experiment. The results indicate that to obtain the evenly grafted FEP-g-PSSA membranes, the higher degree of grafting is required as the film thickness increases, and the lower dose rate are more effective than the higher dose rate at the given dose.

• Radiation Oncology Journal
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• v.17 no.3
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• pp.230-237
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• 1999

Purpose : To elucidate the effects of pentoxifylline and diltiazem on the late response of the salivary glands of the rat after irradiation. Materials and Methods : Sixteen Sprague-Dawley rats were divided into 4 groups : (a) irradiation alone (b) irradiation with pentixifylline (PTX) (c) irradiation with diltiazem (DTZ) (d) irradiation with both PTX and DTZ. Irradiation was given in a single fraction of 16 Gy using 4 MV photon energy through an anterior port encompassing the left side of the salivary gland leaving the right side of salivary gland as a control. PTX, 20 mg/kg and/or DTZ, 50 mg/kg were infused intraperitoneally before irradiation, Two rats from each group were sacrificed on the 10th week and the rest was sacrificed on the 16th week after irradiation. Histopathologic examinations were undertaken for each section and the proportion of vacuolated cells out of the total number of cells under light microscopic fields was calculated. The statistical significance in the difference of the proportion of the vacuolated cells among the experimental groups was evaluated by a $x^2$-test. Results : Irradiated salivary glands of the 10th week group revealed markedly increased number of vacuolated cells compared to those of unirradiated control. The proportion of vacuolated cells was significantly reduced in both the PTX group (p value=0.001) and the combined PTX and DTX group compared to those of irradiation alone group. The DTZ alone group did not reveal the significant reduction of vacuolated cells compared to those of irradiation alone group (p value, >0.05). The 16th week groups revealed similar findings to those of the 10th week group, but the degree of chronic inflammatory cell infiltrates and interstitial fibrosis was increased and the number of acinar cells was reduced compared to those of the 10th week group. Conclusions : PTX significantly reduced the late radiation response of salivary glands, but DTZ did not reduce the same degree as PTX did. Taking the positive results of this study into consideration, it seems reasonable to apply PTX into the clinical trial for the head and neck irradiation to reduce the late radiation sequelae of salivary glands in the near future. At the same time the further experiment to clarify the subcellar mechni는 involved in PTX should be preceded.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.27 no.1
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• pp.43-53
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• 1997

The purpose of this study was to aid in the prediction of tumor cell tolerance to radiotherapy and/or chemotherapy. For this study, cell surviving curves were obtained for mouse lymphoma YAC-1 cell line using semi automated MTT assay. 2, 4,6, 8, 10Gy were irradiated at a dose rate of 210cGy/rnin using /sup 60/Co Irradiator ALDORADO 8. After irradiation, YAC-1 cell lines(3×10⁴cells/ml) were exposed to bleomycin or cisplatin for 1 hour. The viable cells were determined for each radiation dose and/or each concentration of drug at the 4th day. And they were compared to control values. The obtained results were as follows : 1. The surviving curve with gentle slope was obtained after irradiation of 2, 4, 6, 8, 10 Gy on YAC-1 cell line. 2. The cytotoxicity of bleomycin or cisplatin was increased significantly at all concentration of 0.2㎍/ml, 2㎍/ml and 20㎍/ml on YAC-1 cell line (P<0.01). And the cytotoxicity of cisplatin was greater than that of bleomycin at all concentration on YAC-1 cell line (P<0.01). 3. There were no significant differences of surviving fractions among 4Gy, 6Gy and 8Gy after irradiation of each radiation dose with 2㎍/ml of bleomycin compared with irradiation only on YAC-1 cell line. 4. There was significant difference of surviving fraction between 2Gy and 10Gy after irradiation of each radiation dose with 2㎍/ml of cisplatin compared with irradiation only on YAC-1 cell line(P<0.05). 5. There were significant differences of surviving fractions between the groups of irradiation only and the groups of irradiation with 2㎍/ml of bleomycin or cisplatin at all doses of 2, 4, 6, 8 and 10Gy on YAC-1 cell line(P<0.05).