• Food Science and Preservation
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• v.24 no.4
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• pp.524-528
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• 2017

Ricinus communis, belongs to the family Euphorbiaceae, has been known as medicinal plants for treatment of inflammation, tumors, antidiabetic, hepatoprotective and laxative. Compared to many pharmacological studies, the effect of R. communis extract on regulating adipogenesis as therapeutic drug for treating obesity has not been reported. R. communis extract (RCE) was investigated to determine its effects on the adipogenesis by monitoring the status of $Wnt/{\beta}-catenin$ signaling and factors involving the differentiation of adipocytes. The differentiation of 3T3-L1 cells monitored by Oil Red O staining was inhibited in concentration dependent manner by RCE. The luciferase activity of HEK 293-TOP cells containing pTOPFlash with Tcf4 response element-luciferase gene was increased approximately 2-folds by the treatment of RCE at concentrations of $100{\mu}g/mL$ compared to the control. Activation of the $Wnt/{\beta}-catenin$ pathway by RCE was further confirmed by immunocytochemical analysis which shows an increment of nuclear localization of ${\beta}-catenin$. In addition, safety of RCE was verified through performing neural stem cell morphology assay. Among the identified flavonoids in RCE, isoquercitrin was the most abundant. Therefore, these results indicate that the adipocyte differentiation was significantly reduced by isoquercitrin in R. communis. In this study, RCE suppresses the adipogenesis of 3T3-L1 cells via the activation of $Wnt/{\beta}-catenin$ signaling.

• Journal of Radiation Protection and Research
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• v.41 no.3
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• pp.216-221
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• 2016

Background: Very fine radiation-induced aerosol particles are produced in intense radiation fields, such as high-intensity accelerator rooms and containment vessels such as those in the Fukushima Daiichi nuclear power plant (FDNPP). Size measurement of the aerosol particles is very important for understanding the behavior of radioactive aerosols released in the FDNPP accident and radiation safety in high-energy accelerators. Materials and Methods: A combined technique using wire screens and imaging plates was developed for size measurement of fine radioactive aerosol particles smaller than 100 nm in diameter. This technique was applied to the radiation field of a proton accelerator room, in which radioactive atoms produced in air during machine operation are incorporated into radiation-induced aerosol particles. The size of $^{11}C$-bearing aerosol particles was analyzed using the wire screen technique in distinction from other positron emitters in combination with a radioactive decay analysis. Results and Discussion: The size distribution for $^{11}C$-bearing aerosol particles was found to be ca. $70{\mu}m$ in geometric mean diameter. The size was similar to that for $^7Be$-bearing particles obtained by a Ge detector measurement, and was slightly larger than the number-based size distribution measured with a scanning mobility particle sizer. Conclusion: The particle size measuring method using wire screens and imaging plates was successfully applied to the fine aerosol particles produced in an intense radiation field of a proton accelerator. This technique is applicable to size measurement of radioactive aerosol particles produced in the intense radiation fields of radiation facilities.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.3
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• pp.229-238
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• 2010

In order to acquire a realistic forecast for the lifetime and post-closure period of the LILW (Low- and Intermediate-Level Radioactive Waste) repository and to establish the overall management plan associated gas issues. it is essential to carry out the long-term experimental research in a similar condition to actual disposal environment. Regarding this, as a part of the following-up actions on a construction and operation license for the first stage of the LILW repository at Gyeongju city, a large-scale in-situ experiment is being planned. For securing basic data on the experiment, the experimental researches related to gas generation previously performed in foreign countries are reviewed in detail. Consequently, it is judged that data on the gas generation experiment in Finland could be practically applied as the benchmark for our large-scale in-situ experiment because the same disposal concept as the Korean repository is adopted and the experiment is performed in a scale large enough to allow the use of regular waste packages.

• Tunnel and Underground Space
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• v.30 no.1
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• pp.15-28
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• 2020

In this study, a procedure was introduced to estimate strength and deformation modulus of the 3-D discrete fracture network(DFN) systems using the distinct element method(DEM). Fracture entities were treated as non-persistent square planes in the DFN systems. Systematically generated fictitious fractures having similar mechanical characteristics of intact rock were combined with non-persistent real fractures to create polyhedral blocks in the analysis domain. Strength and deformation modulus for 10 m cube domain of various deterministic and stochastic 3-D DFN systems were estimated using the DEM to explore the applicability of suggested method and to examine the effect of fracture geometry on strength and deformability of DFN systems. The suggested procedures were found to effective in estimating anisotropic strength and deformability of the 3-D DFN systems.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.1
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• pp.97-102
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• 2012

Alternate alternating current (AAC) is used in nuclear power plants (NPPs) in order to cope with station black outs (SBOs). AAC has been provided using diesel engine drive types in Korea's NPPs. The structure of gas turbine generators (GTGs) is simpler than that of diesel generators (DGs), and GTGs have the advantage of longer maintenance intervals. However, GTG-AAC was not used in NPPs in Korea because of the lack of operation/maintenance experience. The purpose of this paper is to analyze the safety of APR+ considering a diversity of AAC types. This paper analyzes reliability data, mechanical specifications of DGs and GTGs, and the sensitivity of core damage frequency to the ACC type.

• Membrane and Water Treatment
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• v.9 no.2
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• pp.95-104
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• 2018

Copper pollution around the world has caused serious public health problems recently. The heavy metal adsorption on traditional membranes from wastewater is limited by material properties. Different adsorptive materials are embedded in the membrane matrix and act as the adsorbent for the heavy metal. The carbonized leaf powder has been proven as an effective adsorbent material in removing aqueous Cu(II) because of its relative high specific surface area and inherent beneficial groups such as amine, carboxyl and phosphate after carbonization process. Factors affecting the adsorption of Cu(II) include: adsorbent dosage, initial Cu(II) concentration, solution pH, temperature and duration. The kinetics data fit well with the pseudo-first order kinetics and the pseudo-second order kinetics model. The thermodynamic behavior reveals the endothermic and spontaneous nature of the adsorption. The adsorption isotherm curve fits Sips model well, and the adsorption capacity was determined at 61.77 mg/g. Based on D-R model, the adsorption was predominated by the form of physical adsorption under lower temperatures, while the increased temperature motivated the form of chemical adsorption such as ion-exchange reaction. According to the analysis towards the mechanism, the chemical adsorption process occurs mainly among amine, carbonate, phosphate and copper ions or other surface adsorption. This hypothesis is confirmed by FT-IR test and XRD spectra as well as the predicted parameters calculated based on D-R model.

• Fire Science and Engineering
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• v.31 no.1
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• pp.26-35
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• 2017

Since the Northridge earthquake (1994) and Kobe earthquake (1995), the concept of performance-based design has been actively introduced to design major structures and buildings. Recently, the seismic design code was established for fire protection facilities. Therefore, the important fire protection facilities should be designed and constructed according to the seismic design code. Accordingly, uniform hazard spectra (UHS), with annual exceedance probabilities, corresponding to the performance level, such as operational, immediate occupancy, life safety, and collapse prevention, are required for performance-based design. Using the method of probabilistic seismic hazard analysis (PSHA), the uniform hazard spectra for 5 major cities in Korea with a recurrence period of 500, 1,000, and 2,500 years corresponding to frequencies of (0.5, 1.0, 2.0, 5.0, 10.0)Hz and PGA, were analyzed. The expert panel was comprised of 10 members in seismology and tectonics. The ground motion prediction equations and several seismo tectonic models suggested by 10 expert panel members in seismology and tectonics were used as the input data for uniform hazard spectrum analysis. According to sensitivity analysis, the parameter of spectral ground motion prediction equations has a greater impact on the seismic hazard than seismotectonic models. The resulting uniform hazard spectra showed maximum values of the seismic hazard at a frequency of 10Hz and also showed the shape characteristics, which are similar to previous studies and related technical guides for nuclear facilities.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.1
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• pp.9-16
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• 1990

The safety of concrete nuclear containment structures should be secured against all kinds of loading due to various natural disasters or extraordinary accidental loads. The current design criteria of concrete containment structures are not based on the reliabillty-based design concept but rely on the conventional design concept. In this paper, a probabillty-based reliability analysis were proposed based on a FEM-based random vibration analysis and serviceability limit state of structures. The limit state model defined for the study is a serviceability limit state in terms of the more realistic crack failure that might cause the emission of radioactive materials, and the results are compared with those of the strength limit state. More accurate reliability analyses under various dynamic loads such as earthquake loads were made possible by incorporation the FEM and random vibration theory, which is different from the conventional reliability analysis method. The uncertainties in loads and resistance available in Korea and the refernces were adapted to the situation of Korea, and especially in the case of earthquake, the design earthquake was assessed based on the available re ports on probabilistic description of earthquake ground acceleration in the Korea peninsula.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.12 no.3
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• pp.191-198
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• 2014

Using results of groundwater flow system modeling for a hypothetical deep geological repository site, a distribution of groundwater flow rates at the disposal depth was analyzed and a method of applying this distribution to a safety assessment for a disposal of radioactive wastes was suggested. The distribution of groundwater flow rates was produced by hydraulic heads simulated from regional and local scale groundwater flow models for the hypothetical disposal site. The flow rates at the locations where deposition holes would be located were estimated. These rates were normalized by the maximum of the flow rates in order to probabilistically illustrate a possibility of canister failures at the deposition holes. From the normalized distribution, probabilistic expectations for mass discharges of radionuclides released from the canisters assumed to be failed were calculated and compared with those deterministically estimated under the assumption that the canisters at the same deposition holes were definitely failed. The suggested method can be contributed to constructing a methodology for safety assessment of a geological repository by reflecting natural conditions of a disposal site in more detail.

• Journal of Food Hygiene and Safety
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• v.31 no.4
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• pp.286-293
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• 2016

This study is an experiment for gastric protective effects of ursolic acid. In order to identify the effects of ursolic acid on gastrointestinal disorder, acute and chronic gastritis were also observed using HCl ethanol and indomethacin-induced gastric lesion models, respectively. As for gastric acid, it was also identified through proton pump ($H^+/K^+-ATPase$) inhibiting activity. In regards to protective factor for gastric damage, prostaglandin $E_2$ ($PGE_2$) was quantitatively analyzed. Antibacterial activity experiment was done on Helicobacter pylori (H.pylori), which is known to be the causing factor of chronic gastritis, gastric ulcer and gastric cancer. By making use of AGS cell, it was confirmed that ursolic acid was involved in apoptosis of gastric cancer cell through 4',6-diamidino-2-phenylindol (DAPI) staining and flow cytometry analysis. As a result, ursolic acid reduced gastric lesions caused by HCl ethanol and indomethacin. Ursolic acid inhibited acid secretion by inhibiting proton pump ($H^+/K^+-ATPase$), which is the gastric acid secreting enzyme involved at the final phase of gastric acid secretion. And ursolic acid was identified with gastric mucosa protection effects by increasing the concentration of $PGE_2$, a protective factor of gastric mucosa preservation. The antibacterial activity on H. pylori, which is aggressive factor in gastrointestinal disorder, ursolic acid showed inhibitory effects on H. pylori colonization. In the DAPI nuclear staining, unlike the control group, shape of the nucleus has deformed, and has been observed either shrinked cell or chromatin condensation phenomenon. In the Flow cytometry assay, confirmed the growth rate of apoptosis in a concentration-dependent manner.