• Korean Journal of Food Science and Technology
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• 제30권5호
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• pp.1209-1213
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• 1998

The gamma-radiation sensitivity of four kinds of Escherichia coli O157:H7 was investigated in frozen cells $(-18^{\circ}C)$ with 0.1 M phosphate buffer and inoculated cells in beef. The maximum populations were observed at 12 hr when E. coli O157:H7 was incubated in the tryptic soy broth at $37^{\circ}C$. In the case of the frozen cells at logarithmic phase, the $D_{10}$ and $12D_{10}$ values of four kinds of E. coli O157:H7 were $0.09{\sim}0.15\;kGy$ and $1.08{\sim}1.80\;kGy$, and inactivation factors were $13.33{\sim}22.22$ and $20.00{\sim}33.33$ at radiation doses of 2 and 3 kGy, respectively. The radiosensitivity of inoculated E. coli O157:H7 in beef showed the $D_{10}$ value of $0.30{\sim}0.47\;kGy$, the $12D_{10}$ value of $3.60{\sim}5.64\;kGy$, and inactivation factor of $4.26{\sim}10.00$. The radiosensitivity of the frozen cells was higher than that of the inoculated E. coli O157:H7 in beef. Gamma irradiation at doses within the range of 1.5 to 3 kGy is considered to be an effective method to control E. coli O157:H7 in beef.

• Korean Journal of Agricultural Science
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• 제25권2호
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• pp.149-153
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• 1998

This experiment was carried out to obtain a basic information for new variety development. The local soybean (Glycine max. L) lines used were endowed from Chungnam Agricultural Research and Extension Services. These lines were planted at upland farm of Chungnam Nat'l Univ., College of Agri. after treatment with mutagen $\gamma$-ray. All characteristics measured were decreased due to the $\gamma$-ray treatment than check except the branches of main stem of the Hannam and plant height of the Sobak. Especially the Sobak and the Eunha among these lines were shown very sensitivly than others treated with $\gamma$-ray of 15Krad. Of characteristics surveyed the nodes per plant was very sensitive to $\gamma$-ray, while the grain weight per plant, the pods per plant and the branches per plant were gradually decreased to further radioactivity about $\gamma$-ray treatment. In the Pungsan and the Sobak lines there were not shown significant between major characteristics at treatments including check. Other lines were also not shown positive correlation among characteristics except between stem diameter and branches(0.64*), grain weight and plant height(0.77**) at check of the Eunha, between stem nodes and stem diameter(0.65*) at check of the Kwangan and between number of pods and stem diameter(0.70*) at check of the Danyeop. From result this experiment, some of lines used were to be appeared characters of interest, for example, such as the short stem and the early flowering. Therefore these lines were needed more advanced generations for stability and performance.

• Radiation Oncology Journal
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• 제21권4호
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• pp.315-321
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• 2003

Purpose: This study was peformed to Investigate apoptosis by radiation In the developing fetal rat brain. Materials and Methods: Fetal blains were Irradiated In utero between the 17th and 19th days of fetal life (El7-19) by linear accelerator. A dose of Irradiation ranging from 1 Gy to 4 Gy was used to evaluate dose dependency. To test time dependency the ra)s were Irradiated with 2 Gy and then the fetal brain specimens were removed at variable 41me course; 1, 3, 5, 12 and 24 hours after the onset of irradiation. Immunohistochemlcal staining using in situ 707-mediated dUTP nick end labelling (TUNEL) technlfue was used for apoptotic cells. The cerebral cortex, including three zones on coriicai zone (Cf). Intermediate zone (if), and ventricular zone (VZ), was examined. Results : TUNEL positive cells revealed typical features of apoptotic cells under light microscope In the fetal rat cerebral cortex. Apoptotic cells were not found In the cerebral cortex of non-Irradiated fetal rats, but did appear In the entire cerebral cortex after 1 Gy Irradiation, and were more expensive at the ventricular and Intermediate zones than at the cortical zone. The extent of apoptosis was Increased with Increasing doses of radiation. Apoptosis reached the peak at S hours after the onset of 2 Gy Irradiation and persisted until 24 hours. Conclusion: Typical morphological features of apoplosis by irradiation were observed In the developing fetal rat cerebral cortex. It was more extensive at the ventricular and Intermediate zones than at the cortical zone, which suggested that stem cells or early differentiated cells are more radiosensitive than differentiated cells of the cortical zone.

• the MEAT Journal
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• 통권36호여름호
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• pp.72-86
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• 2009

Microbial reduction, physicochemical property, and sensory evaluation of irradiated beef patty were investigated. The microbial counts of refrigerated beef patty were reduced to below the number of 3 logs after irradiation at 3 kGy. But no viable microorganism was detected in frozen beef patty irradiated at 3 kGy. Food additives such as nitrite, salt, phosphate and ascorbic acid did not affect on the inactivation of microorganism by irradiation. The irradiation effect on the water holding capacity was not significant, but frozen irradiated beef patty showed higher water holding capacity than refrigerated beef patty. The drip loss of irradiated beef patty did not show significant differences according to irradiation doses. Considering the influence of food additives, the irradiated beef patty mixed with salt and phosphate showed lower drip loss than that without food additives. In refrigerated beef patty, TBARS values were increased with increase of irradiation doses and showed lower values in the beef patty mixed with food additives than that without food additives. The redness of refrigerated beef patty showed highest values at 3 kGy of irradiation and then decreased with increasing irradiation doses, while in the frozen beef patty did not show distinct tendency according to the irradiation doses or food additives. In sensory evaluation. the irradiated beef patty showed unpleasant smell as compared with the non irradiated beef patty, but showed somewhat higher score in smell at the sample contained ascorbic acid regardless of irradiation doses.

• Food Science of Animal Resources
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• 제28권4호
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• pp.437-444
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• 2008

Microbial reduction, physicochemical property, and sensory evaluation of irradiated beef patty were investigated. The microbial counts of refrigerated beef patty were reduced to below the number of 3 logs after irradiation at 3 kGy. But no viable microorganism was detected in frozen beef patty irradiated at 3 kGy. Food additives such as nitrite, salt, phosphate and ascorbic acid did not affect on the inactivation of microorganism by irradiation. The irradiation effect on the water holding capacity was not significant, but frozen irradiated beef patty showed higher water holding capacity than refrigerated beef patty. The drip loss of irradiated beef patty did not show significant differences according to irradiation doses. Considering the influence of food additives, the irradiated beef patty mixed with salt and phosphate showed lower drip loss than that without food additives. In refrigerated beef patty, TBARS values were increased with increase of irradiation doses and showed lower values in the beer patty mixed with food additives than that without food additives. The redness of refrigerated beef patty showed highest values at 3 kGy of irradiation and then decreased with increasing irradiation doses, while in the frozen beef patty did not show distinct tendency according to the irradiation doses or food additives. In sensory evaluation, the irradiated beef patty showed unpleasant smell as compared with the non irradiated beef patty, but showed some-what higher score in smell at the sample contained ascorbic acid regardless of irradiation doses.

• Asian Journal of Turfgrass Science
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• 제22권1호
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• pp.25-34
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• 2008

This study was conducted to determine the optimum dose ranges for a mutation breeding based on the observations of a seed germination and an early growth in turfgrasses. Three warm season (Zoysiagrass, Bermudagrass, and Seashore paspalum) and four cool season turfgrasses (Kentucky bluegrass, Tall fescue, Perennial ryegrass, and Creeping bentgrass) were used in this study. We investigated the percentage of a seed germination and a seedling growth after irradiating the turfgrass seeds with various doses of gamma-ray (50, 100, 150, 200, 250, 300, 400, and 500 Gy). After 24 h with a gamma irradiation, the seeds were sown on the wet filter paper in a petri dish and maintained for 3 weeks at 30$^{\circ}C$ for the warm season turfgrasses and at 25$^{\circ}C$ for the cool season turfgrasses. Data on a seed germination and a seedling growth with three replications were collected. The percentage of seed germination was decreased with an increase of the gamma-ray dose. Shoot and root growth, and the fresh weight were decreased significantly as the radiation dose was increased. A radiation dose indicating a 50% growth inhibition ($LD_{50}$) with a gamma irradiation was varied among those turfgrass species used, with the highest at about 500 Gy for bermudagrass and the lowest at 100Gy for tall fescue. The optimum dose for a gamma irradiation for a selection of turfgrass mutants was considered to be about 300, 150, 500, 150, 200, 100 and 200 Gy for zoysiagrass, seashore paspalum, bermudagrass, Kentucky bluegrass, perennial ryegrass, tall fescue, and creeping bentgrass, respectively.

• Journal of radiological science and technology
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• 제26권3호
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• pp.41-49
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• 2003

This study was undertaken to observe the histopathologic changes in submandibular glands of the white rats when exposed to megavoltage fractionated dose of CLINAC 2100 C-D 6 MV X-RAY irradiation and 42 female white rats, weighing approximately 100gm, were divided into control and 2 experimental groups. At sacrifice, submandibular glands were excised and examined microscopically and electromicroscopically. The results were as follows : 1. The acinar cells of submandibular gland showed damage varied with dose, 12 Gy resulted in very mild injury while 24 Gy caused extensive injury. 2. The acinar cells of sumandibular gland showed similar ultrastructual alterations, appeared as pleomorphic nucleus, decreased numbers and pleomorpgism of secretory granules, distention of rough endoplasmic reticulum, expansion and pallor appearance of mitochondria, and hypertrophy of Golgi complex. 3. A serous cells were the most sensitive components, displaying morphological alterations of radiation damage as early as 3 hours, followed by submandibular seromucinous cells and secretory tubular cells. 4. The mucous cells, as well as the whole ductal lining cells, displayed no significant alterations. 5. No evidence of microvascular injury through whole experimental groups indicated that microvascular impairment dose not contribute to early. salivary gland injury.

• Korean Journal of Food Science and Technology
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• 제19권5호
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• pp.403-408
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• 1987

The effects of gamma irradiation on microbiological and chemical qualities of four kinds of poultry feeds were investigated. The viable counts of total bacteria in the samples were $10^5\;to\;10^6/g$. They were reduced by 2 to 3 log cycles after 3 to 5 kGy irradiation, and were completely eliminated with irradiation of 7 kGy. Coliforms and enteric pathogens were contaminated in high levels in all samples, ranging from $1.2{\times}10^4\;to\;1.7{\times}10^5/g\;and\;4.0{\times}10\;to\;2.6{\times}10^3/g$, respectively, They were sterilized by 3 to 5 kGy irradiation. Fungi, ranging from $10^{2}\;to\;10^4/g$, mainly osmophiles were identified as Aspergillus and Penicillium. They were eliminated to a undetectable level by 5 to 10 kGy irradiation. Six kinds of species, including Aspergillus flavus, were potential mycotoxin producers. Chemical components, such as proximate compositions, and mineral contents were not affected by the gamma irradiation. However, TBA values and amino acid content seemed to be affected by gamma irradiation.

• Journal of the Korean Society of Radiology
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• 제15권4호
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• pp.491-498
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• 2021

In this study, the effective dose was measured using the PCXMC v2.0 program by examining the conditions used to set the diagnostic reference level for intraoral imaging recommended by the government, and the effect of the Al additive filter was confirmed. In oral imaging, the largest effective dose was calculated from the oral mucosa among 11 organs. The effect of the Al additive filter showed an excellent radiation reduction effect at 2mm rather than 1mm. In the case of children aged 5 years, the overall effective dose was calculated to be high in all 11 organs because they are more sensitive to radiation than adults. And as a result of evaluating the image quality according to the use of an additional filter during intraoral imaging, there was no significant difference in SNR and CNR changes compared to before the additional filter was used. Based on this study, it is thought that additional filter settings can be recommended for intraoral imaging.

• Journal of radiological science and technology
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• 제47권3호
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• pp.205-211
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• 2024

Currently, with the development of technologies, X-ray examinations for medical examinations at hospital is increasing. This study was conducted to help reduce radiation exposure by measuring the exposure dose received by pediatric patients and the spatial dose of the X-ray room. Dosimeters were installed in the eyeball, thyroid gland, breast, gonads and 4 directions at a distance of 30 cm, 40 cm, 50 cm from the phantom. The dose was measured ten times each, before, and after the application of the bismuth shield under the examination conditions of the head, chest, and abdomen of pediatric patients. Under the condition of head examination, when a shielding was applied, the dose reduction rate was 68.58% for the eyeball, 72.88% for the thyroid, 84.2% for the breast, and 72.36% for the gonad. The chest examination showed reductions of 19.56% eyeball, 56.98% thyroid, 1.21% breast, and 0.68% gonad. The abdominal examination showed reduction rates of 2.6% eyeball, 10.67% thyroid, 19.85% breast, and 82.02% gonad. Spatial dose decreased by 62.25% at 30 cm, 61.16% at 40 cm, and 68.68% at 50 cm. When the bismuth shield was applied, there was a decrease in dose across all examinations, as well as a reduction in spatial dose. Continued research on the use of bismuth shields will help radiological technologists achieve their goal of dose reduction.