• Food Science and Biotechnology
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• v.16 no.1
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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.

• Food Science and Preservation
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• v.16 no.4
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• pp.590-593
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• 2009

The effect of gamma irradiation on the storage stability of Undaria pinnatifida was investigated. A three-log reduction in total aerobic bacteria in U. pinnatifida samples was obtained by irradiation with 3 kGy. During storage for 2 weeks, the viable counts of microorganisms in non-irradiated U. pinnatifida increased to 6 log CFU/g. However, irradiation of U. pinnatifida by 5 kGy eliminated microorganisms. The Hunter $L^{\ast}-value$ of U. pinnatifida was slightly increased after 5 kGy of irradiation. The hardness properties of U. pinnatifida decreased during storage, but were not changed by irradiation with up to 3 kGy. These results indicate that low-dose irradiation (3 kGy) could be effective for improvement of the storage stability of U. pinnatifida.

• Journal of radiological science and technology
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• v.44 no.2
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• pp.101-107
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• 2021

The purpose of this study was to evaluate optimal CT scan parameters to minimize patient dose to the irradiation and maintain satisfactory image quality in low-dose chest computed tomography (CT) scans. In a chest anthropomorphic phantom, chest CT scans were performed at different kVp and mA within reference of 3.4mGy in volume CT Dose Index (CTDI_vol). The following quantitative parameters had been statistically evaluated: image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and figure of merit (FOM). Nine radiographers conducted the blind test to select the optimal kVp-mA combination. Results indicated that the kVp-mA combination of 80kVp-90mA, 100kVp-50mA, 120kVp-30mA and 140kVp-30mA were obtained high SNR and CNR. The 120kVp-30mA combination offered good compromise in the FOM, which showed the quality and dose performance. In the blind test, an image of 80kVp-90mA obtained a high score with 4.7 points, and 120kVp-10mA or 140kVp-10mA with a low tube current were observed severe noise and poor image quality, thus resulting in decreased diagnostic accuracy. On the other hand, in the combination of high kVp and high mA(140kVp-90mA), the image quality was improved, but the radiation dose was also increased. the FOM value of 140kVp-90mA was lower than 120kVp-30mA. The application of appropriate scan parameters in low-dose chest CT scans produced satisfactory results in dose and image quality for the accuracy of the clinical diagnosis.

• The Korean Journal of Food And Nutrition
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• v.26 no.3
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• pp.573-577
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• 2013

To extend the shelf-life of the domestic peach, a low dose UV-C irradiation (0~3.0 $kJ/m^2$) was treated and the changes of the major chemical components were investigated. The contents of polyphenols in UV-treated peaches were higher than that of control with the highest at 0.25 $kJ/m^2$ UV treatment. The contents of polyphenols of control and UV treatments were slightly reduced by storage period. The contents of flavonoid were not significantly different among the control and UV treatments. Detected free sugars of the control and UV treatments were fructose, glucose, maltose and sucrose. Sucrose content was higher than that of other free sugars and free sugar content increased during storage. And free sugar content was not significantly different between the control and UV treatments. The free amino acid content of the control and UV treatments were 115.38 mg% and 95.92~120.94 mg% respectively, but there was no significant difference between the control and UV treatments.

• Bulletin of the Korean Chemical Society
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• v.33 no.7
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• pp.2265-2268
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• 2012

Aqueous solution of oxygenated Direct yellow 12 dye has been evaluated spectrophotometrically as a possible gamma rays dosimeter. The neutral (pH-7), alkaline (pH-12.5) and acidic (pH-5.5) aqueous solution of the dye were prepared and exposed to various gamma doses. Absorption spectra of unirradiated and irradiated solutions were recorded at 400 nm peak. The increase in absorbance with the increase in irradiation dose was observed from 1 to 6 kGy. The stability response of the dye solution for different environmental conditions such as temperature (low & high), light and darkness were investigated during post irradiation storage for ten days. The dye solution showed high stability in darkness for the studied period. The optical density of the dye solution was found to be decreased at high temperature storage.

• Current Photovoltaic Research
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• v.6 no.3
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• pp.81-85
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• 2018

The photovoltaic modules installed in the actual field are affected by various external environments and the electrical performance output value is generally lowered compared to initial output value. The most of photovoltaic modules consists of low iron glass, encapsulant (EVA), back sheet, frame and junction box assembly based on the solar cells. In this paper, the characteristics of encapsulant which is an important constituent material of photovoltaic module were verified by maximum power determination, electro luminescence images, yellowness index measurement, and gel content measurement after ultraviolet (UV) irradiation exposure. The most commonly installed 72 cells crystalline photovoltaic modules were tested after various UV exposure of 0, 15, 30, and $60kWh/m^2$ and compared with the reference module. After UV exposure of $15kWh/m^2$, which is the current international test condition, a small amount of change was observed in yellowness index and electroluminescence, while a gell content rapidly increased. At a cumulative dose of $60kWh/m^2$, which will be a new international test condition in the near future, however, the yellowness index increased sharply and showed the greatest output power drop.

• Korean Journal of Food Science and Technology
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• v.17 no.6
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• pp.474-481
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• 1985

Radurization effects on fried fish meat paste with Co-60 gamma irradiation at 0-5 kGy and physicochemical aspects of the stored samples at low ($3{\pm}1^{\circ}C$, LT) and room ($10-20^{\circ}C$, RT) temperatures were investigated. The initial microbial loads of the samples were $2.2{\times}10^3/g$ in total bacterial count, $2.8{\times}10^2/g$ in yeasts & molds, and $1.0{\times}10^2/g$ in coliform group, respectively. An irradiation dose of more than 3 kGy was shown to be effective for the radurization of stored samples and there is no apparent difference between air and vacuum packaging groups. The chemical components related to the quality underwent similar changes in the nonirradiated and irradiated groups; however, as the storage time was prolonged the quality of nonirradiated samples rapidly deteriorated. Textural parameters of the samples were little affected by the applied doses, and sensory evaluations showed that 3 kGy irradiation was the optimum dose level to extend the shelf-life of fried fish meat paste up to 2 times at RT and 3 to 4 times at LT, respectively compared with the nonirradiated control.

• The Korean Journal of Food And Nutrition
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• v.26 no.1
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• pp.85-91
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• 2013

For shelf-life improvement of the domestic peach, a treatment with low dose UV-C (0~3.0 $kJ/m^2$) irradiation was performed and the spoilage rate and changes of physico-chemical and sensory properties of the peach were investigated. Control showed spoilage at day 4, and then 50% of control showed spoilage at day 8. However, samples treated with low dose UV-C showed lower percentage of spoilage than those of control at day 8. Weight changes of control and the samples with UV-C treatment showed no difference during the storage period. There was no difference in pH of samples among the treatments but they were increased by storage time. Hardness of samples was not different among treatments at initial stage of storage after UV-C treatment. However, the hardness of control sample was decreased faster than those of the samples with low dose UV-C treatment after 6 days of storage. No significant changes in lightness, redness and yellowness of the samples by UV-C treatment were observed. The sensory parameters including taste, flavor, and color at initial and during storage period were not different among treatments except for texture and overall acceptance. The scores for texture and overall acceptance of control were decreased faster than those of UV-C treatments during storage. In general, samples treated with low dose UV-C showed higher sensory quality than control.

• Korean Journal of Food Science and Technology
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• v.49 no.2
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• pp.117-122
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• 2017

The aim of this study was to evaluate the quality characteristics of fresh red paprika treated by electron-beam irradiation at quarantine doses. The initial microbial loads were low with $10^4$ and $10^2$ colony-forming units/g for total aerobic bacteria and coliform, respectively; however, a dose of 1 kGy resulted in load reduction of 1 log cycle. A dose level of more than 1 kGy caused significant decreases in the hardness and carotenoid content parameters. An applied dose level of less than 2 kGy did not affect vitamin C content; however, a decrease of 87-90% was observed after 40-day storage. Samples treated with 2 kGy showed significantly lower acceptance compared to the control, with lower sensory evaluation scores for color and texture. Therefore, e-beam irradiation at dose range of 0.4 and 1 kGy was found to be appropriate for quarantine applications for microbiological control and quality maintenance of paprika.

• Journal of Radiation Protection and Research
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• v.40 no.1
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• pp.25-35
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• 2015

We analyzed the differential effects of histopathology, apoptosis and expression of radiation response genes after chronic low dose rate (LDR) and acute high dose rate (HDR) radiation exposure in spleen, lung and liver of rats. Female 6-week-old Sprague-Dawley rats were used. For chronic low-dose whole body irradiation, rats were maintained for 14 days in a $^{60}Co$ gamma ray irradiated room and received a cumulative dose of 2 Gy or 5 Gy. Rats in the acute whole body exposure group were exposed to an equal dose of radiation delivered as a single pulse ($^{137}Cs$-gamma). At 24 hours after exposure, spleen, lung and liver tissues were extracted for histopathologic examination, western blotting and RT-PCR analysis. 1. The spleen showed the most dramatic differential response to acute and chronic exposure, with the induction of substantial tissue damage by HDR but not by LDR radiation. Effects of LDR radiation on the lung were only apparent at the higher dose (5 Gy), but not at lower dose (2 Gy). In the liver, HDR and LDR exposure induced a similar damage response at both doses. RT-PCR analysis identified cyclin G1 as a LDR-responsive gene in the spleen of rats exposed to 2 Gy and 5 Gy gamma radiation and in the lung of animals irradiated with 5 Gy. 2. The effects of LDR radiation differed among lung, liver, and spleen tissues. The spleen showed the greatest differential effect between HDR and LDR. The response to LDR radiation may involve expression of cyclin G1.