• Food Science of Animal Resources
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• v.38 no.5
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• pp.1043-1054
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• 2018

Salmonellosis caused by chicken consumption has been a critical issue in food safety worldwide, including in Korea. The probability of illness from consumption of chicken was simulated in study, based on the recipe of Dakgalbi, a commonly eaten chicken dish in Korea. Additionally, the processing stage at slaughterhouses to decrease Salmonella concentration in broilers was modeled to explore its effect on the likelihood of illness. A Monte Carlo simulation model was created using @RISK. Prevalence of Salmonella in chickens at the retail stage was found to be predominantly important in determining the probability of illness. Other than the prevalence, cooking temperature was found to have the largest impact on the probability of illness. The results also demonstrated that, although chlorination is a powerful tool for decreasing the Salmonella concentration in chicken, this effect did not last long and was negated by the following stages. This study analyzes the effects of variables of the retail-to-table pathway on the likelihood of salmonellosis in broiler consumption, and also evaluates the processing step used to decrease the contamination level of Salmonella in broilers at slaughterhouses. According to the results, we suggest that methods to decrease the contamination level of Salmonella such as chlorination had little effect on decreasing the probability of illness. Overall, these results suggest that preventing contamination of broiler with Salmonella must be a top priority and that methods to reduce the concentration of Salmonella in broilers at slaughterhouses hardly contribute to safe consumption of Salmonella-contaminated chicken.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.spc
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• pp.75-87
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• 2020

The Korea Atomic Energy Research Institute (KAERI) has developed geological repository systems for the disposal of high-level wastes and spent nuclear fuels (SNFs) in South Korea. The purpose of the most recently developed system, the improved KAERI Reference Disposal System Plus (KRS⁺), is to dispose of all SNFs in Korea with improved disposal area efficiency. In this paper, a system-level safety assessment model for the KRS⁺ is presented with long-term assessment results. A system-level model is used to evaluate the overall performance of the disposal system rather than simulating a single component. Because a repository site in Korea has yet to be selected, a conceptual model is used to describe the proposed disposal system. Some uncertain parameters are incorporated into the model for the future site selection process. These parameters include options for a fractured pathway in a geosphere, parameters for radionuclide migration, and repository design dimensions. Two types of SNF, PULS7 from a pressurized water reactor and Canada Deuterium Uranium from a heavy water reactor, were selected as a reference inventory considering the future cumulative stock of SNFs in Korea. The highest peak radiological dose to a representative public was estimated to be 8.19×10^-4 mSv·yr^-1, primarily from ¹²⁹I. The proposed KRS⁺ design is expected to have a high safety margin that is on the order of two times lower than the dose limit criterion of 0.1 mSv·yr^-1.

• 대한방사선방어학회:학술대회논문집
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• 2011.11a
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• pp.212-213
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• 2011

The biological effects of low dose ionizing radiation (LDIR) remain insufficiently understood. We examined for the scientific evidence to show the biological effects of LDIR using radiation-sensitive immune cells. We found that Ikaros protein was responsed to low dose-dependent effects of gamma radiation in IM-9 B lymphocytes. Ikaros encodes zinc finger transcription factors that is important regulators of a hematopoietic stem cells (HSCs) progression to the B lymphoid lineage development, differentiation and proliferation. In this study, we observed that cell proliferation was enhanced from 10% to 20% by LDIR (0.05 Gy) in IM-9 B lymphocytes. The Ikaros protein was phosphorylated in its serine/threonine (S/T) region and decreased its DNA binding activity in the cells exposed to LDIR. We found that Ikaros phosphorylation was up-regulated by CK2/AKT pathway and the residues of ser-304 and ser-306 in Ikaros was phosphorylated by LDIR. We also observed that Ikaros protein was localized from the nucleus to the cytoplasm after LDIR and bound with Autotaxin (ENPP2, ATX) protein, stimulating proliferation, migration and survival of immune cells. In addition, we found that the lysoPLD activity of ATX was dependent on Ikaros-ATX binding activity. These results indicate that the Ikaros is an important regulator of immune activation. Therefore, we suggest that low dose ionizing radiation can be considered as a beneficial effects, stimulating the activation of immune cells.

• Clean Technology
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• v.23 no.3
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• pp.256-269
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• 2017

In response to national and international regulations for resource circulation and to reduce greenhouse gas emissions, the automotive industry has tried to reuse scrap parts and defective products produced in the disposal or production stages as recycled resources. Attempts have been made to reach the target recycling rate by reducing the number of material types required for each part. Moreover, in order to achieve greenhouse gas reduction targets while maintaining the performance of existing products, lighter components are being developed. Existing products were 100% incinerated at the disposal stage, but the uni-materialized products were improved to be possible that it could be recycled 90% through scraps and the defective product in the pre-production and production stage. It also appears that the fuel efficiency improves through 56% lightweight compared to the existing product. In this paper, a preliminary assessment is conducted on the applicability of uni-materialized product development of car parts. The environmental impact values of existing products and developed prototypes are compared and analyzed through life cycle assessment.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.245-245
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• 2017

Heavy metal pollution of agricultural soils affects land productivity and has impact on the quality of surrounding ecosystem. Soil microbial community parameters are used as reliable indices for assessing quality of agricultural lands under metal stress. This study investigated bacterial community structure of polluted and undisturbed paddy soils to elucidate soil factors that are related to alteration of bacterial communities under conditions of metal pollution. No obvious differences in the richness or diversity of bacterial communities were observed between samples from polluted and control areas. The bacterial communities of three locations were distinct from one another, and each location possessed distinctive set of bacterial phylotypes. The abundances of several phyla and genera differed significantly between study locations. Variation of bacterial community was mostly related to soil general properties at phylum level while at finer taxonomic levels concentrations of arsenic and lead were significant factors. According to results of bacterial community functional prediction, the soil bacterial communities of metal polluted locations were characterized by more abundant DNA replication and repair, translation, transcription and nucleotide metabolism pathway enzymes while amino acid and lipid metabolism as well as xenobiotic biodegradation potential was reduced.Our results suggest that the soil microbial communities had adapted to the elevated metal concentrations in the polluted soils as evidenced by changes in relative abundances of particular groups of microorganisms at different taxonomic resolution levels, and by altered functional potential of the microbial communities.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.3
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• pp.41-50
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• 2017

The purpose of this study were to evaluate the effect of best management practices (BMPs) of Haean highland agricultural catchment ($62.8km^2$) under future climate change using SWAT (Soil and Water Assessment Tool). Before future evaluation, the SWAT was setup using 3 years (2009~2011) of observed daily streamflow, suspended solid (SS), total nitrogen (T-N), and total phosphorus (T-P) data at three locations of the catchment. The SWAT was calibrated with average 0.74 Nash and Sutcliffe model efficiency for streamflow, and 0.78, 0.63, and 0.79 determination coefficient ($R^2$) for SS, T-N, and T-P respectively. Under the HadGEM-RA RCP (Representative Concentration Pathway) 4.5 and 8.5 scenarios, the future precipitation and maximum temperature showed maximum increases of 8.3 % and $4.2^{\circ}C$ respectively based on the baseline (1981~2005). The future 2040s and 2080s hydrological components of evapotranspiration, soil moisture, and streamflow showed changes of +3.2~+17.2 %, -0.1~-0.7 %, and -9.1~+8.1 % respectively. The future stream water quality of suspended solid (SS), total nitrogen (T-N), and total phosphorus (T-P) showed changes of -5.8~+29.0 %, -4.5~+2.3 %, and +3.7~+17.4 % respectively. The future SS showed wide range according to streamflow from minus to plus range. We can infer that this was from the increase of long-term rainfall variability in 2040s less rainfalls and 2080s much rainfalls. However, the results showed that the T-P was the future target to manage stream water quality even in 2040s period.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.4
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• pp.123-132
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• 2018

The purpose of this study was to evaluate the reduction effect of non point source (NPS) pollution in Haean highland agricultural catchment ($62.8km^2$) for 13 BMP scenarios under RCP (Representative Concentration Pathway) 4.5 and 8.5 scenarios. Under the present climate condition, the BMP (best management practices) reduction efficiency of SS (suspended solid), T-N (total nitrogen), and T-P (total phosphorus) showed +25.7%, +4.2%, and +16.1% for VFS (vegetative filter strip), +0.1%, +15.6%, and +5.7% for FC (fertilizer control), and +6.3%, -2.9%, and +3.9% for RSM (rice straw mulching) respectively. In general, effective was the best for SS and T-P reductions, and the FC was the best for T-N reduction. The negative effect of T-N on RSM was induced by increase in infiltration and solute transport to baseflow. Under the future climate change scenarios, the SS, T-N, and T-P reduction efficiency showed the range of +1.9~+11.6%, -1.9~+0.2%, and +5.3~+11.9% respectively. The 3 BMPs (VFS, FC, and RSM) application in the future showed negative and little differences (-0.5~+1.6%) for SS and T-N reduction efficiencies while T-P reduction efficiency showed +0.3~+7.6% comparing with the baseline period. To achieve an increase in the reduction efficiency of future SS and T-N by +2~+10%, the combined application of more than two BMPs is necessary.

• Management & Information Systems Review
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• v.34 no.3
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• pp.61-78
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• 2015

The purpose of this study is to analyze the impact of cash holdings on internationalization of listed manufacturing firms. We explore moderating effect of managerial ownership between cash holdings and internationalization of firms. We analysed cross-sectional data of 645 listed companies from 2000 to 2013 using the fixed effects estimation. Empirical results showed that the there was a positive significant relation between cash holdings and internationalization of firms This study also found that managerial ownership have a significant negative moderating effects in the pathway between cash holdings and internationalization Cash liquidities can be rapidly induced internationalization. Managerial ownership increase agency cost, therefore, it might have a negative effects on internationalization These results suggest that agency cost with cash holdings is very important for cash management.

• The Korean Journal of Pain
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• v.20 no.2
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• pp.106-110
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• 2007

Background: A phosphodiesterase 5 inhibitor, sildenafil, has been effective against nociception. Several lines of evidence have demonstrated the role of the GABAergic pathway in the modulation of nociception. The impact of the GABA receptors on sildenafil was studied using the formalin test at the spinal level. Methods: Male SD rats were prepared for intrathecal catheterization. The formalin test was induced by subcutaneous injection of formalin solution. The change in the activity of sildenafil was examined after pre-treatment with GABA receptor antagonists ($GABA_A$ receptor antagonist, bicuculline; $GABA_B$ receptor antagonist, saclofen). Results: Intrathecal sildenafil dose-dependently attenuated the flinching observed during phase 1 and 2 in the formalin test. The antinociceptive effect of sildenafil was reversed by the $GABA_B$ receptor antagonist (saclofen) but not by the $GABA_A$ receptor antagonist (bicuculline) in both phases. Conclusions: Intrathecal sildenafil suppressed acute pain and the facilitated pain state. The antinociception of sildenafil is mediated via the $GABA_B$ receptor, but not the $GABA_A$ receptor, at the spinal level.

• Economic and Environmental Geology
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• v.46 no.1
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• pp.63-69
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• 2013

This paper discusses important environmental issues that must be considered during shale gas development. Shale gas has been attracting many attention as the next key energy resource with its large abundance through easily accessible production fields, and its lower carbon dioxide & sulfur dioxide emission profile upon combustion when compared to the conventional oil and natural gas resources. Successful development of a shale gas field requires the use of hydraulic fracturing to recover hydrocarbon through the very tight shale formation, which has been frequently associated with environmental contamination issue of water, soil, and atmosphere. Therefore, environmental issues and their solution to minimize environmental impact should be considered for successful development of shale play in a future.