• Korean Chemical Engineering Research
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• v.54 no.3
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• pp.431-435
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• 2016

The aim of this study was to investigate the effect of gamma irradiation on the pretreatment of wood chips with NaOH solution. The degree of saccharification was quantified by measuring reducing sugar and glucose concentrations after enzymatic hydrolysis. After pretreatment with 10 g/L NaOH, the wood chips were irradiated at the doses of 0, 50, 100, and 200 kGy, respectively. Among the irradiated samples, wood chips irradiated at the dose of 200 kGy had the highest reducing sugar concentration of 12.2 g/L. Also, to define the effect of irradiation before pretreatment, the wood chips were first gamma-irradiated and then pretreated with NaOH. When the NaOH treatment was conducted after irradiation at 200 kGy, the reducing sugar content was further increased to 13.4 g/L and glucose content of the wood chip was as high as 7.9 g/L. These results suggest that gamma irradiation may be the promising method for pretreatment of cellulose biomass.

• The Journal of Korean Society for Radiation Therapy
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• v.31 no.2
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• pp.51-63
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• 2019

Purpose: Radiation therapy for breast cancer should consider the change in breast shape due to breathing and swelling. In this study, we evaluate the benefit of using virtual bolus for IMRT of left breast cancer. Materials and methods: 10 patients with early breast cancer who received radiation therapy after breastconserving surgery compared the VMAT and IMRT plans using the virtual bolus method and without using it. The first analysis compared the V95%, HI, CI of treatment volume, Dmean, V5, V20, V30 of ipsilateral lung, and Dmean of heart in VMAT plan made using the virtual bolus method(VMAT_VB) to the plan without using it(VMAT_NoVB) in case there is no change in the breast. In IMRT, the same method was used. The second analysis compared TCP and NTCP based on each treatment plan in case there is 1cm expansion of treatment volume. Result: If there is no change in breast, V95% in VB Plan(VMAT_VB, IMRT_VB) and NoVB Plan(VMAT_NoVB, IMRT_NoVB) is all over 99% on each treatment plan. V95% in VMAT_NoVB and VMAT_VB is 99.80±0.17% and 99.75±0.12%, V95% in IMRT_NoVB and IMRT_VB is 99.67±0.26% and 99.51±0.15%. Difference of HI, CI is within 3%. OAR dose in VB plan is a little high than NoVB plan, and did not exceed guidelines. If there is 1cm change in breast, VMAT_NoVB and IMRT_NoVB are less effective for treatment. But VMAT_VB and IMRT_VB continue similar treatment effect compared in case no variation of breast. Conclusion: This study confirms the benefit of using a virtual bolus during VMAT and IMRT to compensate potential breast shape modification.

• The Korean Journal of Nuclear Medicine
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• v.28 no.2
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• pp.186-191
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• 1994

Tc-99m MIBI, a lipophilic cation, was reported as a useful agent for localization of lung cancer. The effect of radiation therapy on the uptake of Tc-99m MIBI in lung cancer, however, was not well evaluated. The aim of the present study was to elucidate the usefulness of Tc-99m MIBI SPECT in the localization and the assessment of radiotherapy in non-small cell lung cancer. Twenty patients(19 males and 1 female, mean age 59, 16 squamous cell ca and 4 adenoca) were studied with Tc-99m MIBI SPECT before radiation therapy. Eleven patients(10 males and 1 female, mean age 59, 8 squamous cell ca and 3 adenoca) were repeated the study 1 month after the completion of radiation therapy(mean dose 6453cGy). All patients showed positive uptakes of Tc-99m MIBI in their tumors. One patient showed a hot uptake in atelectatic area. There was no difference of Tc-99m MIBI uptakes between squamous cell ca and adenoca either on planar or tomographic images. Tc-99m MIBI uptake ratios of squamous cell ca and adenoca were $1.50{\pm}0.16$ and $1.45{\pm}0.15$ on planar images, and $2.73{\pm}0.46$ and $2.54{\pm}0.37$ on tomographic images, respectively. The concordance between radiological change(chest x-ray and CT) and change of Tc-99m MIBI uptakes was 9/11 (81.8% ). In conclusion, Tc-99m MIBI SPECT was useful in the localization of tumor and the assessment of radiation therapy in non-small cell lung cancer.

• Journal of the Korean Society of Radiology
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• v.14 no.5
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• pp.553-561
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• 2020

In this study aims to investigate the radiation protection effect of avocado peel extracts on the Sprague-Dawely rats. 52 male rats were randomly classified into 4 groups. NC Group was a normal control group, PA Group was a group injected avocado peel extracts, IR Group was irradiated group, and lastly PA+IR Group was set as an irradiated group after injected of avocado peel extracts. Avocado peel extract was administered orally at 200 mg/kg once a day for 14 days before irradiation, and the radiation dose was systemically irradiated with 6 MV X-ray of 7 Gy. On the 4 and 21 days after irradiation, the experimental animals were sacrificed to evaluate the change in blood cell composition, spleen index, and histopathological evaluation of the liver and small intestine. As a result, the PA+IR Group showed a significantly greater recovery of lymphocytes(p<0.01), red blood cells(p<0.01), and platelets(p<0.05) than the IR Group. It was also confirmed that the activation of Superoxide Dismutase(SOD) was further increased. Histopathologically, observed that nuclei aggregation and cytoplasmic expansion were slightly reduced in the PA+IR Group in the liver. and the damage was significantly reduce(p<0.01) in the change of villi length due to damage to the small intestine cells. Based on the above results, avocado peel extract can be expected to act as a radiation protection agent that can reduce damage to blood cells and major organs caused by irradiation.

• Radiation Oncology Journal
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• v.4 no.1
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• pp.15-20
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• 1986

From 1979 to 1984, 39 local allograft irradiations were given to 29 patients: 10 irradiations were administered for prevention and 29 for reversal of acute rejection of transplanted kidney. Three doses of 150 cGy every other day were combined with high-dose of methylprednisolone pulse (1 gm/day) for 3 days. For prevention of acute rejection, local irradiation was delivered on the days 1, 3, and 5 after the transplantation, and for reversal, irradiation started after the diagnosis of acute rejection. Eight out of 10 patients irradiated for prevention had acute allograft rejection, and, what is more, there was no surviving graft at 15 months after transplantation. Reversal of acute rejection was achieved in $71\%$. When the pre-irradiation level of serum creatinine was below $5.5mg\%$, the reversal rate was $93\%$, but above $5.5mg\%$ the reversal rate was only $17\%$ (p<0.01). Reirradiation after failure was not successful. Among 15 reversed patients, $7(47\%)$ had subsequent rejection (s). The functional graft survivals at 6 month, 1, 2, and 3 year were $70\%,\;65\%,\; 54\%,\;and\;54\%$, respectively. Therapeutic irradiation resulted in better graft survival when serum creatinine was below $5.5mg\%$ (p<0.001) or when irradiation started within 15 days after the diagnosis of acute rejection (p<0.001).

• Environmental Mutagens and Carcinogens
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• v.18 no.2
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• pp.116-122
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• 1998

The present investigation has been performed to elucidate the effect of pretreatment with low dose of ultraviolet radiation (UV), ethyl methansulfonate (EMS), and bleomycin (BLM) on cell survival and lectin-binding glycoconjugates of plasma membrane in HeLa cells treated with mutagen. The percentage of survival of cells pretreated with 1 mM EMS following treatment with 10 mM EMS was higher than that of cells treated with 10 mM EMS alone. Wheat germ agglutinin (WGA) staining intensity of cells pretreated with 1 mM EMS and subsequently treated with 10 mM EMS was stronger than that of cells treated with 10 mM EMS alone. But, succinylated wheat germ agglutinin (sWGA) staining intensity of cells pretreated with 1 mM EMS and subsequently treated with 10 mM EMS was similar to that of cells treated with 10 mM EMS alone. These results suggest that the acquired resistance to EMS is related to the glycoconjugates containing sialic acid of plasma membrane involved in multidrug resistance or adaptive response in HeLa cells.

• Korean Journal of Food Science and Technology
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• v.41 no.6
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• pp.694-699
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• 2009

The antimutagenic activities of ethanol extracts of Korean and American propolis were tested using Salmonella Typhimurium TA98 with two indirect mutagens of 3-amino-1,4-dimethyl-5H-pyrido [4,3-b]indole (Trp-P-1) and 2-aminoanthracene (2-AA) with S9 mix. Additionally, their antimicrobial activities against acne-related pathogenic strains of Propionibacterium acnes, Staphylococcus Epidermidis, Staphylococcus aureus and Pseudomonas aeruginosa were evaluated using both paper disk method and agar dilution method. Ethanol extracts of Korean and American propolis showed strong inhibitory effects, in a dose dependant manner, against the mutagenicities induced by Trp-P-1 and 2-AA. The antimutagenic effect of ethanol extracts of Korean propolis showed significantly higher protective activity than that of American propolis against the Trp-P-1 induced mutagenicity of S. Typhimurium TA98 at the lower concentration ($1-10\;{\mu}g$), but significantly lower protective activity at the higher concentration ($50-200\;{\mu}g$). The antimutagenic effect of ethanol extract of Korean propolis showed significantly higher protective activity than that of American propolis against the 2-AA induced mutagenicity at the concentration of $1\;{\mu}g$, but significantly lower protective activity than that of the American at the higher concentration ($50-200\;{\mu}g$). Both extracts showed strong antimicrobial activities against all the acne-related pathogens tested, with minimal inhibitory concentration (MIC) values in the range $1,500-5,000\;{\mu}g/mL$.

• Journal of the Korean Society of Radiology
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• v.9 no.4
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• pp.239-247
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• 2015

It should be accurate dose calculation to increase the efficiency of radiation therapy, and it is priority to figure out the beam characteristics for this purpose. The target and primary collimator in head components of the linear accelerator have the greatest influence on determining the beam characteristics which is caused by backscatter and it is the factor to consider the shielding structures and equipment management. In this study, we made modeling of the linear accelerator through the Geant4 Monte Carlo simulation and investigated backscatter according to the change of the size and shape in head components. For the scattered electrons, it showed the greatest number of distributions inside of the inner radius at primary collimator. But, for the scattered photons which have the high energy, it was mostly located outside of the inner radius at primary collimator. Scattered positrons showed a small occurrence in about 0.03%. According to the change of the inner radius at primary collimator, it was great changes in the inside of inner radius for all three scattered particles. According to the change of the outer radius at primary collimator, it was shown some considerable effects from more than 60 mm outer radius. It was no significant effect according to the change of target thickness. In this study, we found that backscatter should be considered, and figured out that geometric size and shape of the peripheral components are the factors that influences the backscatter effect.

• Food Science and Preservation
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• v.15 no.6
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• pp.922-926
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• 2008

The effect of UV-C irradiation on microbial growth and the quality of imported dried filefish and octopus during storage was examined. Samples of imported dried filefish and octopus were irradiated at 0, 5, 10 and $20\;kJ/m^2$ and stored for 3 months at $20^{\circ}C$ or for 6 days at $4^{\circ}C$. Exposure times of 5 min 33 sec, 11 min 6 sec, and 22 min 12 sec were used. UV-C treatment of the imported dried filefish and octopus decreased the populations of aerobic bacteria, yeasts and molds in proportion to radiation dose. Compared to the control, total aerobic bacteria, and yeast and mold populations were significantly lower (1-2 log CFU/g) with UV-C treatment of $20\;kJ/m^2$. UV-C irradiation caused negligible changes in the Hunter color L, a and b values. These results indicate that UV-C irradiation could be useful in inhibiting microbial growth on imported dried fish without impairing quality during storage.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6413-6419
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• 2013

This study examined the irradiation effect of high energy x-rays on the hatching process of fertilized eggs, particularly with regard to malformation and blood cells change. The experimental groups were five day old fertilized eggs irradiated with x rays at doses of 5, 7.5, 10 Gyusing alinear accelerator. The control group was not irradiated. After three weeks, hatched chicks were sacrificed and examined for blood sampling. The survival rate of the x-ray irradiated groups were significantly lower than that of the control group (46.7vs 80%). The malformation rate of the experimental groups was60%, whereas no congenital malformations were observed in the control group. The experimental groups had a significantly higher malformation rate. The types of malformation were left wing defect, proptosis, microcephaly, cervical spine, and feet anomaly. The incidence of malformation increased with increasing radiation dose. The white blood cell count of control group and eachexperimental groups (5 and 7.5 Gy) were 87.64, 100.76 and 81.42 ($10^3/{\mu}L$), respectively. X-ray irradiation of 5 day old chick embryos increased the rate of death and malformation significantly.The malformations were estimated to have occurred by chromosomal abnormalities. Further genetic studies will be needed to confirm the correlation between high energy X-rays and the cause of malformations.