• Journal of Biosystems Engineering
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• v.38 no.2
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• pp.87-94
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• 2013

Purpose: Pineapple is now the third most important tropical fruit in world production after banana and citrus. Phytosanitary irradiation is recognized as a promising alternative treatment to chemical fumigation. However, most of the phytosanitary irradiation studies have dealt with physiochemical properties and its efficacy. Accurate dose calculation is crucial for ensuring proper process control in phytosanitary irradiation. The objective of this study was to optimize phytosanitary irradiation treatment of pineapple in various radiation sources using Monte Carlo simulation. Methods: 3-D geometry and component densities of the pineapple, extracted from CT scan data, were entered into a radiation transport Monte Carlo code (MCNP5) to obtain simulated dose distribution. Radiation energy used for simulation were 2 MeV (low-energy) and 10 MeV (high-energy) for electron beams, 1.25 MeV for gamma-rays, and 5 MeV for X-rays. Results: For low-energy electron beam simulation, electrons penetrated up to 0.75 cm from the pineapple skin, which is good for controlling insect eggs laid just below the fruit surface. For high-energy electron beam simulation, electrons penetrated up to 4.5 cm and the irradiation area occupied 60.2% of the whole area at single-side irradiation and 90.6% at double-side irradiation. For a single-side only gamma- and X-ray source simulation, the entire pineapple was irradiated and dose uniformity ratios (Dmax/Dmin) were 2.23 and 2.19, respectively. Even though both sources had all greater penetrating capability, the X-ray treatment is safer and the gamma-ray treatment is more widely used due to their availability. Conclusions: These results are invaluable for optimizing phytosanitary irradiation treatment planning of pineapple.

• Journal of Ginseng Research
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• v.22 no.1
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• pp.66-72
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• 1998

Studies were performed to determine the effect of Korean red ginseng (extract powder, spray-dried), it is made of choice 6-year-old raw ginseng roots, and processed by steaming and drying, on jejunal crypt survival, endogenous spleen colony formation, and apoptosis in jejunal crypt cells of irradiated mice. Jejunal crypts were protected by pretreatment of red ginseng (1 mg/head, single I.P. at 24hours before irradiation, p<0.05). Red ginseng administration before irradiation (1 mg/head, single I.P at 24hours before irradiation) resulted in an increase of the formation of endogenous spleen colony (p<0.05). The frequency of radiation-Induced apoptosis in intestinal crypt cells was also reduced by treatment of red ginseng both pretreatment (P.O.: 2 mg/ml of drinking water for 7 days, p<0.005, I.P.: 1 mg/head, single I.P. at 24 hours before irradiation, p<0.005) and post-treatment (1 mg/head, single I.P at 30 minutes after irradiation, p<0.05). These results indicated that Korean red ginseng might be a useful radio-protector, especially since it is a relatively nontoxic natural product. Further studies are needed to characterize better the promotion nature of red ginseng and its fractions.

• Applied Science and Convergence Technology
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• v.27 no.2
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• pp.42-45
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• 2018

Photovoltaic and optoelectronic devices based on hybrid metal halide perovskites ($MAPbX_3$; $MA=CH_3NH_3{^+}$, $X=Cl^-$, $Br^-$, or $I^-$) are rapidly improving in power conversion efficiency. Also, during recent years, perovskite single crystals have emerged as promising materials for high-efficiency photovoltaic and optoelectronic devices because of their low defect density. Here we show that the light soaking effect of mixed halide perovskite ($MAPbBr_{3-x}I_x$) single crystals can be explained using photoluminescence, time-resolved photoluminescence, and Raman scattering measurements. Unlike Br-based single crystal, Br/I mixed single crystal show a strong light soaking effect under laser irradiation condition that was related to the existence of multiple phases.

• Imaging Science in Dentistry
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• v.33 no.3
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• pp.179-185
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• 2003

Purpose: To investigate the effects of irradiation on the phenotypic expression of the MC3T3-El osteoblastic cell line, particularly on the expression of osteocalcin and osteopontin. Materials and Methods: Cells were irradiated with a single dose of 0.5, 1,4, and 8 Gy at a dose rate of 5.38 Gy/min using a cesium 137 irradiator. After the specimens were harvested, RNA was extracted on the 3rd, 7th, 14th, and 21st day after irradiation. The RNA strands were reverse-transcribed and the resulting cDNAs were subjected to amplification by PCR. Results: The irradiated cells demonstrated a dose-dependent increase in osteocalcin and a dose-dependent decrease in osteopontin mRNA expression compared with the non-irradiated control group, The amount of osteocalcin mRNA expression decreased significantly at the 3rd day after irradiation of 0,5, 1,4, and 8 Gy, and also decreased significantly at the 3rd, 14th, and 21 st day after irradiation in the 8 Gy exposed group compared with the control group, The degree of osteopontin mRNA expression increased significantly at the 7th day after irradiation of 0,5, 1,4, and 8Gy, Conclusion: These results showed that each single dose of 0,5, 1, 4, and 8 Gy influenced the mRNA expression of osteocalcin and osteopontin associated with the calcification stage of osteoblastic cells, suggesting that each single dose affected bone formation at the cell level.

• Journal of Food Hygiene and Safety
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• v.30 no.1
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• pp.92-97
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• 2015

The aim of this study is to examine the removal efficiency of pathogen (Escherichia coli O157:H7 and Salmonella typhimurium) on meat and fish products (packing condition: vacuum or not and storage temperature: $4^{\circ}C$ or $-20^{\circ}C$) repeatedly exposed at low-dose gamma irradiation. In case of meat products (beef and chicken), E. coli O157:H7 was not observed at the level of 2 kGy single gamma irradiation and 0.5 kGy repeated gamma irradiation and S. Typhimurium was not observed at the level of 2 kGy single gamma irradiation and 1 kGy repeated gamma irradiation. In case of fish products, E. coli O157:H7 and S. Typhimurium were not detected at the level of 0.5 kGy single and repeated gamma irradiation. These results showed that microorganisms on fish products were more efficiently removed than those of meat products with low-dose gamma irradiation. Generally, each packing condition made no difference. However, the products (fish and meat) stored at $-20^{\circ}C$ needed more higher dose gamma irradiation than products at $4^{\circ}C$.

• New & Renewable Energy
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• v.2 no.1 s.5
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• pp.56-65
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• 2006

The thermal performance of glass evacuated tube solar collectors are numerically and experimentally investigated. Four different shapes of solar collectors are considered and the performances of these solar collectors are compared. Dealing with a single collector tube, the effects of not only the shapes of the absorber tube but also the incidence angle of solar irradiation (beam irradiation) on thermal performance of the collector are studied. However, the solar irradiation consists of the beam irradiation as well as the diffuse irradiation. Also, the interference of solar irradiation and heat transfer interaction between the tubes exist in an actual solar collector, These effects are considered in this study experimentally and numerically. The accuracy of the numerical model is verified by the experimental results. The result shows that the thermal performance of the absorber used a plate fin and U-tube is the best.

• Proceedings of the KIEE Conference
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• 2009.04a
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• pp.40-42
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• 2009

The economic growth and highly industrialized society have increased the demand for electricity power. As a result, concerns were focused on the energy resource scarcity and global warming. That is why the photovoltaic generation system to address these concerns has been in the spotlight recently. In this thesis, a utility interactive photovoltaic generation system was operated experimentally for the purpose of promoting the spread of the photovoltaic generation system in the future. Also, the effect of the type of array structure has on the performance of the photovoltaic generation system was evaluated quantitatively and by analyzing the comprehensive operating characteristics, the following results were obtained. In the demo system operated for a year, the average irradiation was measured to be 455,076 $[W/m^2]$ and the maximum irradiation to be 626,622 $[W/m^2]$ in May, up 171,546 $[W/m^2]$ or 38[%] compared with the average irradiation. The minimum irradiation was observed to be 294,022$[W/m^2]$ in December, down 161,054 $[W/m^2]$ or 35[%] compared with the average irradiation. The generation power in situation where there is plenty of irradiation was more than the average one, and the generation power in the fixed system amounted to 32[%], the single-axis tracker to 37[%], and the dual-axis tracker to 39[%]. The generation power in situation where there is little irradiation was less than the average one, and the generation power in the dual-axis tracker amounted to 41[%], the single-axis tracker to 40[%], and the fixed system to 36[%].

• Radiation Oncology Journal
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• v.7 no.2
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• pp.157-169
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• 1989

Radiological and clinical evidences indicate that hyperthermia combined with irradiation produce a significant improvement in therapeutic effect of cancer The experiences obtained from 90 rats' kidney A single dose of irradiation ranged from 6Gy, 8Gy and 10Gy was delivered on the rat's kidney. The combined therapy group had the same irradiation after hyperthermia at $42\~44^{\circ}C$ for 30 minutes. Microscopic examination and calculation of thermal enhancement ratio were carried out, and the results were as follows: 1. In the group of hyperthermia alone, there were moderate glomerular congestion and mild tubular degeneration on light microscopic examination. 2. In the group of irradiation alone, tubular degeneration was noted in 6Gy irradiation and its severity was increased along with radiation dose. 3. In the group of hyperthermia combined with irradiation, tubular degeneration and necrosis were appeared in 6Gy and 10Gy irradiation, respectively. 4. On electron microscopic examination, proximal convoluted tubular and glomerular changes in irradiation group were similar to that of combined with hyperthermia, and its severity was increased along with observation periods. 5. Thermal enhancement ratio (TER) was 1.0 after evaluation of histipathologic changes in rat's kidney, with combination therapy.

• Radiation Oncology Journal
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• v.4 no.1
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• pp.1-13
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• 1986

In order to clarify the effect of radiation on the mouse jejunal crypt cells by combined administration of administration and radiation and also to evaluate the enhancing effect of adriamycin, the authors performed this study by delivering single irradiation of 1,000 to 1,600 rad to the whole abdomen of mice by cobalt-60 teletherapy unit. In combination with adriyamycin treatment groups, the drug was administered as single dose of 10 mg/kg either 2 hours before or 4 hours after graded single dose,900 to 1,400 rad, of irradiation. The authors studied the quantitative changes of intestinal crypt cells by microcolony survival assay technique and the morphological changes of small intestinal villi by scanning electron microscope in mice following to combined therapy with adriamycin and irradiation, The average number of jejunal crypts per circumference was $130{\pm}16$ in control group. The mean lethal dose(Do) of each irradiation alone and combined therapy groups 2 hours before and 4 hours after irradiation, were 160, 170, and 170 rad in cell survival curves, respectively. The dose effect factor(DEF) of adriamycin in each groups of pre-irradiation and post-irradiation were 1.19 and 1.26, respectively. The conical shaped villi were noted on 1,200 rad in irradiation alone group and 1,000 rad in combined groups. For the proper clinical application we must be careful of the radiation injury to small bowel when the anticancer chemotherapy and radiation therapy to the abdomen and pelvic area are used as combined therapeutic modality.

• Preventive Nutrition and Food Science
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• v.10 no.1
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• pp.29-33
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• 2005

To facilitate establishing regulations for irradiated foods, Korean traditional soybean-based fermented powdered doenjang (PD), kanjang (PK), kochujang (PKC) and chungkukjang (PC) were irradiated at 1, 3, 5 and 7 kGy, and subjected to irradiation detection analyses as part of establishing a database for detecting irradiated foods. Photostimulated luminescence (PSL) and electron spin resonance (ESR) were applied as the detection methods. Using PSL analysis, the irradiated PD, PK and PKC could be easily distinguished from the non-irradiated ones, while irradiation of the PC at 5 kGy or higher was detectable. The ESR spectra of the irradiated PD, PK and PKC exhibited symmetrical multiplet lines, which might be induced from the crystalline sugar, whereas, the PC showed a single signal at the paramagnetic centers. The signal intensity increased with incremental increases of irradiation doses distinguishing the irradiated samples from the control. In addition, the peak height also revealed that irradiation induced an increment in the intensity of single and/or multiplet lines of the ESR signals, resulting in clear confirmation of irradiation. Thus, the data from this study could be used as references for detecting irradiated soybean-based fermented powdered sauces.