• Nuclear Engineering and Technology
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• v.52 no.11
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• pp.2460-2470
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• 2020

To study the thermophysical and neutronic properties of thorium-plutonium fuel, a conceptual design of a hybrid facility consisting of a subcritical Th-Pu reactor core and a source of additional D-D neutrons that places on the axis of the core is proposed. The source of such neutrons is a column of high-temperature plasma held in a long magnetic trap for D-D fusionreactions. This article presents computer simulation results of generation of thermonuclear neutrons in the plasma, facility neutronic properties and the evolution of a fuel nuclide composition in the reactor core. Simulations were performed for an axis-symmetric radially profiled reactor core consisting of zones with various nuclear fuel composition. Such reactor core containing a continuously operating stationary D-D neutron source with a yield intensity of Y = 2 × 10¹⁶ neutrons per second can operate as a nuclear hybrid system at its effective coefficient of neutron multiplication 0.95-0.99. Options are proposed for optimizing plasma parameters to increase the neutron yield in order to compensate the effective multiplication factor decreasing and plant power in a long operating cycle (3000-day duration). The obtained simulation results demonstrate the possibility of organizing the stable operation of the proposed hybrid 'fusion-fission' facility.

• Smart Structures and Systems
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• v.15 no.2
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• pp.335-353
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• 2015

Previous long-term measurements of the Uldolmok tidal current power plant showed that the structure's natural frequencies fluctuate with a constant cycle-i.e., twice a day with changes in tidal height and tidal current velocity. This study aims to improve structural health monitoring (SHM) techniques for offshore structures under a harsh tidal environment like the Uldolmok Strait. In this study, lab-scale experiments on a simplified offshore structure as a lab-scale test structure were conducted in a circulating water channel to thoroughly investigate the causes of fluctuation of the natural frequencies and to validate the displacement estimation method using multimetric data fusion. To this end, the numerical study was additionally carried out on the simplified offshore structure with damage scenarios, and the corresponding change in the natural frequency was analyzed to support the experimental results. In conclusion, (1) the damage that occurred at the foundation resulted in a more significant change in natural frequencies compared with the effect of added mass; moreover, the structural system became nonlinear when the damage was severe; (2) the proposed damage index was able to indicate an approximate level of damage and the nonlinearity of the lab-scale test structure; (3) displacement estimation using data fusion was valid compared with the reference displacement using the vision-based method.

• Nutritional Sciences
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• v.5 no.4
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• pp.203-210
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• 2002

Aster scaber $T_{HUNB}$ (AST ; Charm-chui), a potent herbal medicinal plant, has a long tradition of use, being harvested as a wild plant, is said to stimulate appetite, and may act as a diuretic, antifebrile agent and painkiller. This study was conducted to investigate the immunomodulative effects of AST In mice, using in vitro and in vivo experiments. The immunomodulative effects were studied in vitro by measuring the proliferation of mice splenocytes and the production of three kinds of cytokines (IL-$\beta$, IL-6, and TNF-$\alpha$) by mice peritoneal macrophages which were cultured with sequential fractions of AST methanol extract (methanol, hexane, chlo-roform, ethylacetate, butanol and water). In an in vivo experiment using mice, different concentrations of AST water extract were orally administrated every other day for two weeks. The production of cytokines (IL-1$\beta$, IL-6, and TNF-$\alpha$) secreted by activated macrophages, and the proliferation of mice splenocytes, were used as indices for immunocompetence. In vitro supplementation using six fractions of AST in the range of 1 to 100$\mu$ g/ml enhanced splenocyte proliferation by 10.5% to 53% compared to the control. IL-1$\beta$production was significantly increased with the supplementation of butanol and water extracts of AST. Higher levels of IL-6 and TNF-$\alpha$production were detected with supplementation of methanol, ethylacetate, butanol or water extracts at the concentration of 100$\mu$ g/ml. In the in vivo study, the highest proliferation of splenocytes was seen in the mice orally administrated with the AST water extract at the concentration of 500mg/kg body weight. In the case of cytokine production, there were no significant differences in the production of IL-1$\beta$and IL-6 among the treated groups and the control. However, TNF-$\alpha$released by activated peritoneal macrophages were augmented by the oral administration of AST water extract. These results indicate that AST may enhance the immune functions by regulating splenocyte proliferation and cytokine production capacity in mice.

• Journal of Environmental Health Sciences
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• v.39 no.4
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• pp.346-353
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• 2013

Objectives: The goal of this study is to identify the distribution of the foliar fluorine content of vegetation surrounding the area where hydrofluoric acid was accidently released in Gumi, Gyeongsangbuk-do on September 27, 2012. In addition, it also aims to estimate the concentration of hydrogen fluoride in the air on the day of the accident. Methods: Samples of plant leaves were collected on October 7, 2012 within 1 km from the site where the accident occurred. These samples were analyzed for soluble fluorine ion with an ion selective electrode. The ambient concentration of hydrogen fluoride was calculated using the fluoride content in the plant via the dose-rate equation (${\Delta}F$=KCT). Results: The arithmetic and geometric means of the concentrations were 2158.2 and 1183.7mg F $kg^{-1}$ for leaves and, 2.4 and 1.1 ppm HF for the air, respectively. The highest concentration of hydrogen fluoride in the air was 14.7 ppm, which is higher than the maximum concentration reported by the government (1 ppm) and the exposure limit (ceiling, 3 ppm). The concentrations of both fluorine and hydrogen fluoride decreased with increasing distance from the accident site and showed a significant decrease outside of a 500m radius from the site (p <0.05). Conclusions: The area around the accident site was highly polluted with hydrogen fluoride according to the results of this study. Considering the persistency of hydrogen fluoride in the environment, long-term monitoring and environmental impact assessment should be pursued.

• Toxicological Research
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• v.30 no.2
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• pp.131-138
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• 2014

Radix Astragali, the root of Astragalus (A.) membranaceus, has been applied in a variety of diseases for a long time in Asian countries such as Korea and China. In addition, the aerial parts such as leaves and stems of A. membranaceus have received a great deal of attention. Recently, the polysaccharide fraction showing a potent immunomoduating activity was isolated from the aerial parts of A. membranaceus. Thus, the aerial parts of A. membranaceus would be worthy enough for a food material and a dietary supplement. However, they should be safe even though valuable. In our previous study, it was estimated that NOAEL for female rats are 5000 mg/kg/day of the crude polysaccharide fraction from A. membranaceus-aboveground parts. As a series of safety evaluation, genotoxicity test for the crude polysaccharide fraction was carried out in this study. In conclusion, the three genotoxicity assays provided strong overall support that the crude polysaccharide fraction lacks mutagenic and/or clastogenic potential under the GLP-based test conditions. This indicates the aerial parts of A. membranaceus would be safe enough for a food material and a dietary supplement.

• Journal of Plant Biotechnology
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• v.29 no.2
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• pp.79-84
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• 2002

Suppression subtractive hybridization (SSH) was used to isolate wound-induced cDNAs from wounded soybean. One of wound-induced cDNA, gmwi33 showed high homology with genes encoding $\beta$-amyrin synthase. The full length cDNA of gmwi33, designated GmAMS1, is 2416 bp long and contains an open reading frame consisted of 739 amino acids. GmAMS1 protein showed 89% identity with licorice GgbAS1 and 86% identity with pea OSCPSY. In 5 day-old, dark-grown seedlings, the expression of GmAMS1 was most strongly induced by light and weakly induced by methyl jasmonate and by low temperature. However, GmAMS1 was not induced by elicitor or UV-B treatment. Such expression pattern might be closely related with the oxygen-radical scavenging activity of soyasaponin.

• FLOWER RESEARCH JOURNAL
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• v.18 no.4
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• pp.303-307
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• 2010

A new spray chrysanthemum cultivar 'Snow Bowl' was released by National Institute of Horticultural & Herbal Science(NIHHS), Rural Development Administration (RDA), in 2008. The cross was made in 2005 between '03B1-230', breeding lines of NIHHS and 'Sei-Alps'. Trials were conducted from 2006 to 2008 for the evaluation and selection of this cultivar, including shading cultures in summer and retarding cultures in spring. The natural flowering time of 'Snow Bowl' is late October, but year-round flowering is possible by photo-periodic control. It has single type flowers with white petals. The growth of plant is very vigorous and it is resistant to white rust. The diameter of flower is 6.3cm. Number of flowers per stem and petals per flower are 12 and 31, respectively. Days to flowering under the short day treatment is about 59 and its vase life is 24.1 days in autumn season. 'Snow Bowl' was applied as No. 2009-179 on February 18, 2009 for variety protection and the plant variety protection rights have been registered as No. 3239 on August 3, 2010 at the Korea Seed and Variety Service.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.67-67
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• 2021

The genus Glycyrrhiza (Licorice) has been used as an oriental herbal medicine for a long time in Asian countries. Wongam (WG), which is Glycyrrhiza new variety, have been developed to improve limitation of licorice including low productivity, environmental restriction and insufficient components by Korea Rural Development Administration. To using WG as a herbal medicine, it is important to reveal the adverse effects in health. In this study, we evaluated the genotoxicity test of WG extract through in vitro bacterial reverse mutation (AMES) assay, in vitro chromosomal aberration assay and in vivo mouse bone marrow micronucleus assay. When compared with the control, WG extract with or without the S9 mix showed no genotoxicity in the AMES assay up to 5000 ㎍/plate and in the chromosomal aberration assay up to 1100 ㎍/ml. In micronucleus assay, no significant increase in the number of micronucleated polychromatic erythrocytes or in the mean ratio of polychromatic to total erythrocytes up to 5000 mg/kg/day for 2 days. The present study demonstrated that WG extract is safe and reliable herbal medicine since no detectable genotoxic effects at least under the conditions of this study.

• Korean Journal of Environmental Biology
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• v.19 no.1
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• pp.59-69
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• 2001

Among the biodegradability tests, TOC-HANDAI and OECD method were utilized to examine the degree of biodegradation of endocrine disruptors, Bisphenol A (BPA) and Nonylphenol. Both methods used natural water microcosms and measured their biodegrada-bilities of BPA and Nonylphenol, in terms of TOC or DOC degradation with time for 28 days. Biodegradabilities for BPA, 73-78% with TOC-HANDAI method and 77-81% with OECD method were obtained respectively at the end of experiment. There was no difference in BPA degradation between two methods. BPA degradation was described by two distinct first order decay rates (k$_1$ and k$_2$) which could be separated by a simple visual fitting. Most of the initial decay reaction accelerated within 1-7 days with k$_1$of 0.24-0.34 $day^{-1}$. And the following another long term first order decay coefficient (k$_2$) showed 0.02-0.05 day$^{-1}$ with much flat slope. About 20-25% of initial BPA remained at the end of experiment. It suggests that the remaining TOC components in BPA biodegradation considered to be refractory metabolites of BPA. Nonylphenol at each sampling point was appeared to be mineralized 20-48% of initial TOC concentration. Consequently Nonylphenol seems more recalcitrant against biodegradation. BPA was not detected in the detection limit of ppb in the watershed of Daechung reservoir and Kum river. However 25 ppb concentration of BPA was detected at the influent of industrial wastewater treatment plant in Taejon.

• The Korea Journal of Herbology
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• v.34 no.2
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• pp.41-47
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• 2019

Objectives : A traditional herbal prescription, Kyung-Ok-Ko (KOK), has long been used in oriental medicine as an invigorant for age-related diseases, such as amnesia and stroke. However, the beneficial value of KOK for immune responses is largely unknown. Based on the above mentioned effects of KOK, other previous reports, and its use in traditional medicine, we hypothesized that KOK displays beneficial effects against methotrexate (MTX)-induced immune suppression. Methods : We investigated the effects of KOK (0.6 g/kg/day, oral (p.o.)) on deteriorated immunity caused by MTX (2 mg/kg/day, p.o.) in an immune suppression mouse model. MTX was fed to mice once a day for 7 days. After the immune responses of the mice deteriorated by MTX treatment, KOK in water was fed to the mice once a day for 14 days. We then measured the expression levels of various cytokines, such as T helper cell (Th1, Th2) cytokines, and the number of immune cells, such as spleen T cells, B cells, and macrophages. Results : The data showed that MTX decreased Th1 profiles (interferon $(IFN)-{\gamma}$, interleukin (IL)-2, IL-12) and the number of immune cells, and increased Th2 profiles (IL-4, IL-5, IL-13), which were normalized significantly by post-administration of KOK. However, there was no significant difference in body-weight gain between MTX- and KOK-treated mice. Conclusion : These results indicate that KOK has immune-enhancing functions and reduces immunotoxicity of MTX, suggesting that supplementation with KOK will improve immune responses clinically and be useful for the prevention of immune-related diseases.