• Journal of the Korean Society of Radiology
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• v.5 no.6
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• pp.383-389
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• 2011

This study offered a new method to calculate absorbed dose of actual patients through Monte Carlo Simulation by using the linkage of Geant4 and DICOM, and, the experimental value of absorbed dose at the center and Geant 4 simulation result according to the depth of PMMA mock phantom were compared by using MOSEF in order to verify Geant4 calculation code. In the area where there was no air space between the irregular gap due to incomplete compression of PMMA slab, the differences were $0.46{\pm}4.69$ percent and $-0.75{\pm}5.19$percent in $15{\times}15cm^2$ and $20{\times}20cm^2$ respectively. Excluding the error due to incomplete compression of PMMA mock phantom, the calculation values of the Monte Carlo simulation by linkage of Geant4 and DICOM was the same.

• Korean Journal of Digital Imaging in Medicine
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• v.13 no.3
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• pp.133-137
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• 2011

This research investigated how low dose radiation affected the quality characteristics of Takju. The treatment group were the quality characteristics of control group, Takju treated by radiation of separate 4, 7, 10 Gy and sterilized Takju. We measured pH, titratable acidity, alcohol, brix, total viable cell count, Hunter's color values, sensory characteristic. As a result, We discovered there were minute changes in pH, titratable acidity, alcohol, brix, total viable cell count. Likewise, The color appeared changes on separate radiation dose. In the sensory characteristic, People's preference ranked better than average level according to priority Takju treated by 4, 7, 10 radiation. In conclusion, Low dose radiation had little effect on the quality characteristics of Takju. However, Takju received a favorable review by some people In test of taste such as after taste. So We thought, such as preservation, the research using the radiation should be continually conducted.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.3
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• pp.638-645
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• 1999

This study was done to investigate effects of ${\gamma}$ irradiated beef feeding on the formation of gluta thione S transferase placental form positive(GST P+) foci, lipid peroxidation, cytochrome P450 system and microsomal glucose 6 phosphate activity in diethylnitrosamine(DEN) initiated rat hepatocarci nogenesis. Weaning Sprague Dawley male rats were fed the diet containing ${\gamma}$ irradiatied ground beef at the dose of 0, 3, 5kGy as a 20% of protein source for 8 weeks. One week after feeding, rats were intraperitoneally injected twice with a dose of DEN(50mg/kg BW). As a promoter, 0.05% phenobarbital was fed in drinking water from one week after DEN treatment until the end of experiment. At the end of 8th week, rats were sacrificed and hepatic GST P+ foci, microsomal malondialdehyde(MDA) and conjugated diene contents were determined. In addition, cytochrome P450 content and the activities of NADPH cytochrome P450 reductase and glucose 6 phosphatase were also measured. There was no significant effect by gamma irradiation on microsomal MDA content, conjugated diene, cytochrome P450 content and activities of NADPH cytochrome P450 reductase and glucose 6 phosphatase. However with DEN treatment, microsomal MDA content and conjugated diene contents were significantly changed. Cytochrome P450 content was also significantly increased while microsomal glucose 6 phophatase activity was significantly decreased with DEN treatment. However activity of NADPH cytochrome P450 reductase was not affected. An interesting finding in this study was that the number and area of hepatic GST P+ foci of the rats fed gamma irradiated beef were significantly(p<0.05) lower than those of the control. Such a lowering effect on GST P+ foci formation was highest at the dose of 3kGy than others. Overall results suggest that the consumption of low dose of gamma irradiated beef does not affect the formation of lipid peroxide, cytochrome P450 system and membrane stability.

• Radiation Oncology Journal
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• v.9 no.2
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• pp.351-359
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• 1991

The current LINAC technique for radiosurgery utilizes a single isocenter approach with multiple noncoplanar arcs. This approach results in spherical dose distributions in the target. Many arteriovenous malformations and tumors suitable for radiosurgical treatment have non-spherical or irregular shapes. The basic approach presented in this paper is to use two or multiple isocenters with standard arcs to shape irregular target volumes through the use of multiple spherical targets. Selection of reasonable irradiation parameters in the first stage is critical to the success of real-time optimization. A useful guideline for optimum isocenter separation and collimator size is developed to shape the target margin uniformly with an desired isodose surface for an elongated target. The implementation of multiple isocenters with three dimensional dose model and application of multiple isocenters approach to several cases are discussed.

• Journal of the Korean Society for Nondestructive Testing
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• v.18 no.6
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• pp.477-483
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• 1998

Hysteresis loop, Barkhausen noise(BN), and hardness were measured in the neutron irradiated RPV steel for various fluence, irradiated dose up to $10^{18}n/cm^2$. The coercivity, remanence and maximum induction of neutron irradiated samples did not change significantly, but the BNA and BNE were decreased as the neutron irradiation increased. The changes of BNE and BNA were characterized by three stages with respect to neutron dose. The BNA and BNE were decreased with an increase of neutron dose to $10^{12}n/cm^2$, and remained nearly constant up to $10^{16}n/cm^2$, then were decreased rapidly with an increase of the neutron dose above $10^{16}n/cm^2$. On the other hand, the hardness was observed revesely with the change of BNA and BNE.

• Journal of Radiation Industry
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• v.8 no.1
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• pp.35-42
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• 2014

This study was conducted to analyze the protective capacity of cyanidin-3-glucoside (C3G), which is rich in mulberry and blackberry as an anthocyanin pigment. In this study, we found that treatment with C3G significantly reduced ROS production in hydrogen peroxide $(H_2O_2)-treated$ HepG2 cells in a dose-dependent manner. In addition, treatment with C3G significantly increased the cell viability in a dose-dependent manner in $H_2O_2-treated$ HepG2 cells. Moreover, treatment with C3G dose-dependently decreased the release of LDH and activation of caspase-3 in HepG2 cells treated with $H_2O_2$. Furthermore, the DNA damage in $H_2O_2-treated$ HepG2 cells was decreased by C3G treatment when compared with the control group in a dose-dependent manner. Additionally, treatment with C3G recovered the activity of antioxidant enzymes such as superoxide dismutase and catalase in $H_2O_2-treated$ HepG2 cells. To summarize, these results suggest that C3G protects cells from $H_2O_2-induced$ oxidative damage by activating antioxidant enzymes.

• Journal of Radiation Protection and Research
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• v.22 no.1
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• pp.1-7
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• 1997

Radiation protection by post-irradiation injection of the ginseng extract in mice was studied. Male ICR mice, 7 weeks old, were orally injected with ginseng extrat(100mg/kg) for 10 days, and with physiologocal saline as the control. Immediately after final injection, mice were whole body irradiated with 5.08Gy(Cs-137 ${\gamma}$-ray, central dose rate : 654Gy/h) which induced Bone marrow death. At 24h after irradiation, micronucleus test and metaphase analysis in bone-marrow were carried, blood cell were counted and the survival rate were carried for 30 days after the irradiation. Stimulated recovery by the extract was observed in thrombocyte count, but that phenomenom was not showed in the erythrocyte and leucocyte counts. The 30-day survival ratio was 5% and 65% for the control and experimental group. Frequencies of micronuclei per 1000 polychromatic erythrocytes were 79.5${\pm}$1.5 in experimental group, 185.9${\pm}$35.8 in control. And Abnormal chromosomes per 50 metaphases were 112 in experimental group and 143 in control.

• Applied Biological Chemistry
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• v.10
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• pp.63-68
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• 1968

The effects of $^{60}Co-{\gamma}$ radiation on the change of composition and susceptibility to soft rot during the storage of sweetpototoes and the radioresistance of spores of the soft rot fungus were investigated and the following results were obtained. 1) Gamma-irradiation of sweetpotatoes caused the increase in water-soluble sugar content and the decrease in ascorbic acid content during the storage. 2) The rate of oxygen uptake in sweetpotato slices becomes higher as the dose increases. But the oxygen uptake in slices irradiated with higher doses decreases along with the color change as the time passes. 3) Irradiation with high doses (above $2.5{\times}10^5$ rad) brought about the increased susceptibility to soft rot decay as the chilling injury did in the storage of sweetpotatoes. 4) Average lethal dose for the spores of Rhizopus nigricans was $3.0{\times}10^5$ rad and the complete death required the level of $1.25{\times}10^6$ rad.

• Journal of the Korean Vacuum Society
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• v.21 no.2
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• pp.78-85
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• 2012

In order to improve the adhesion between poly-monochloro-para-xylylene (Parylene-C) film and Aluminum thin film, the surface of Parylene-C film was irradiated by ${O_2}^+$ and $Ar^+$ ion beam generated by duoplamatron ion source. The ion dose of $Ar^+$ and ${O_2}^+$ was changed from $5{\times}10^{14}$ to $1{\times}10^{17}/cm^2$ and the ion beam energy was 1 kV. Contact angles of water on Parylene-C modified by $Ar^+$ and ${O_2}^+$ ion irradiation decreased from $78^{\circ}$ to around $17^{\circ}$, and $9^{\circ}$, respectively. X-ray photoelectron spectroscopy analysis shows that the hydrophilic groups were formed on the surface of Parylene-C by chemical reaction between the unstable chains induced by the ion irradiation and oxygen ions or residual oxygen gas. The hydrophilic groups were identified as C-O bond, C=O bond and (C=O)-O bond. The cross cut tape test which was applied to characterize the adhesion between Al thin film and Parylene-C film modified by ${O_2}^+$ ions irradiation shows that the adhesion strength was improved as increasing ion dose.

• Applied Chemistry for Engineering
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• v.30 no.6
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• pp.698-706
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• 2019

Over the last few decades, there have been a lot of efforts to develop soft actuators, which can be external stimuli-responsive and applied to the human body. In order to fabricate medical soft actuators with a dynamic precision control, the 3D crosslinked poly(acrylic acid) (PAAc)/poly(vinyl alcohol) (PVA)/poly(ethylene glycol) (PEG) hydrogels were synthesized in this study by using a radiation technique without noxious chemical additives or initiators. After irradiation, all hydrogels showed high gel fraction over 75% and the ATR-FTIR spectra indicated that PAAc/PVA/PEG hydrogels were successfully synthesized. In addition, the gel fraction, equilibrium water content, and compressive strength were measured to determine the change in physical properties of PAAc/PVA/PEG hydrogels according to the irradiation dose and content ratio of constituents. As the irradiation dose and amount of poly(ethylene glycol) diacrylate (PEGDA) increased, the PAAc/PVA/PEG hydrogels showed a high crosslinking density and mechanical strength. It was also confirmed that PAAc/PVA/PEG hydrogels responded to electrical stimulation even at a low voltage of 3 V. The bending behavior of hydrogels under an electric field can be controlled by changing the crosslinking density, ionic group content, applied voltage, and ionic strength of swelling solution.