• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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• pp.588-592
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• 2015

Soil testing is one of the major strategies for establishing sustainable agricultural practice as it analyzes nutrient contents of soil and determines the amount of nutrients required for crop growth. Soil testing for the field cultivating regional major crops in Korea has been conducting by National Academy of Agricultural Science (NAAS), provincial agricultural research & extension services and agriculture technology centers since 2000. 1,006,227 soil samples were analyzed and uploaded on Korean soil information system (http://soil.rda.go.kr) from 2003 to 2013. Soil pH has changed from 6.1 to 6.2. Organic matter (OM), available (Avail.) phosphate and exchangeable (Exch.) K have decreased from 24 to $23gkg^{-1}$, 541 to $399mgkg^{-1}$ and 0.90 to $0.72cmol_ckg^{-1}$ between 2003 and 2013, respectively. Especially, Exch. Ca contents decreased to $5.7cmol_ckg^{-1}$ in 2009 and increased to $6.2cmol_ckg^{-1}$ in 2013. Ratios of optimal ranges for cropping were 48% for pH, 22% for OM, 26% for Avail. phosphate, and 23, 16, 22% for Exch. K, Ca and Mg in 2013. Ratios of optimal ranges for pH increased and low ranges for OM, Avail. phosphate and Exch. K increased. Frequency distribution was 64% for pH 5.5~7.0, 65% for OM $10{\sim}30gkg^{-1}$, 48% for Avail. phosphate under $300mgkg^{-1}$ and 23, 29, 22% for Exch. K 0.2~0.6, Ca 4.0~6.0 and Mg $1.0{\sim}1.5cmol_ckg^{-1}$.

• Journal of Navigation and Port Research
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• v.42 no.6
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• pp.378-387
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• 2018

In this paper, the towing force for the LNG bunkering barge was investigated. Currently, LNG bunkering barge is being developed as an infrastructure for the bunkering of LNG (Liquefied Natural Gas), an eco-friendly energy source. In the case of the LNG bunkering barge, self-propulsion is considered through retrofit from an operating point. Therefore, the LNG bunkering barge's shape is similar to that of the ship as compared to a towed barge, so a rule of the towed barge overestimates the towing force. In order to improve accuracy, the calm water resistance was calculated using ITTC 1978 method which considers wave resistance by the Rankine source method. The added resistance in waves was calculated using the modified radiated energy method which considers the shortwave correction method of NMRI. The performance of the towing resistances through the calm water resistance and the added resistance in waves was compared to rules associated with towed barges.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.2
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• pp.141-158
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• 2019

Objectives: An adverse outcome pathway is a biological pathway that disturbs homeostasis and causes toxicity. It is a conceptual framework for organizing existing biological knowledge and consists of the molecular initiating event, key event, and adverse output. The AOP concept provides intuitive risk identification that can be helpful in evaluating the carcinogenicity of chemicals and in the prevention of cancer through the assessment of chemical carcinogenicity predictions. Methods: We reviewed various papers and books related to the application of AOPs for the prevention of occupational cancer. We mainly used the internet to search for the necessary research data and information, such as via Google scholar(http://scholar.google.com), ScienceDirect(www.sciencedirect.com), Scopus(www.scopus. com), NDSL(http: //www.ndsl.kr/index.do) and PubMed(http://www.ncbi.nlm.nih.gov/pubmed). The key terms searched were "adverse outcome pathway," "toxicology," "risk assessment," "human exposure," "worker," "nanoparticle," "applications," and "occupational safety and health," among others. Results: Since it focused on the current state of AOP for the prediction of toxicity from chemical exposure at work and prospects for industrial health in the context of the AOP concept, respiratory and nanomaterial hazard assessments. AOP provides an intuitive understanding of the toxicity of chemicals as a conceptual means, and it works toward accurately predicting chemical toxicity. The AOP technique has emerged as a future-oriented alternative to the existing paradigm of chemical hazard and risk assessment. AOP can be applied to the assessment of chemical carcinogenicity along with efforts to understand the effects of chronic toxic chemicals in workplaces. Based on these predictive tools, it could be possible to bring about a breakthrough in the prevention of occupational and environmental cancer. Conclusions: The AOP tool has emerged as a future-oriented alternative to the existing paradigm of chemical hazard and risk assessment and has been widely used in the field of chemical risk assessment and the evaluation of carcinogenicity at work. It will be a useful tool for prediction, and it is possible that it can help bring about a breakthrough in the prevention of occupational and environmental cancer.

• 한국노년학
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• v.38 no.1
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• pp.27-45
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• 2018

The purpose of this study was to identify between the successful aging-related predictive factors and the successful aging in the middle aged office. The predictive factors of successful aging such as subjective health condition, cognitive functions, self-esteem, and social support were confirmed by the existing literature. The population of the study was the middle aged office employees, who are generally defined an age group from 40 to 60. The sample of this study was targeted to employees working at companies registered to securities, KSDAQ, and KONEX in Korea. SPSS WIN 23.0 and AMOS 21.0, and M-plus 6.12 were used for the data analysis. The findings of this study were presented below. First, the result of the structural relationship between the predictive factors of successful aging (subjective health condition, cognitive function, self-esteem, and social support) and successful aging was appropriate as RMSEA=.059, TLI=.932, CFI=.944. Second, subjective health condition and social support were significant variables for successful aging but cognitive function and self-esteem were not significant. Third, social support, which is a social factor, was the most influential among other variables. Based on the results, theoretical and practical implications were presented.

• Korean Journal of Food Science and Technology
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• v.50 no.6
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• pp.688-696
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• 2018

This study aimed to investigate the effects of red ginseng-derived saponin fraction (SF) on lipid accumulation, reactive oxygen species (ROS) production, and nuclear factor (erythroid-derived 2)-like 2 (Nrf2)/Kelch-like ECH-associated protein 1 (Keap1) signaling during adipocyte differentiation. SF effectively inhibited lipid accumulation, with the downregulation of adipogenic factors such as peroxisome proliferator-activated receptor gamma ($PPAR{\gamma}$) and CCAAT/enhancer-binding protein alpha ($C/EBP{\alpha}$). A high dose of SF decreased the protein levels of $PPAR{\gamma}$ and $C/EBP{\alpha}$ by over 90% compared to the control. SF-mediated downregulation of adipogenic factors was due to the regulation of early adipogenic factors including $C/EBP{\beta}$ and $Kr{\ddot{u}}ppel$-like Factor 2 (KLF2). In addition, SF ($200{\mu}g/mg$) decreased intracellular ROS generation by 40% during adipocyte differentiation. However, the SF significantly upregulated Nrf2 and its target proteins, hemoxygenase-1 (HO-1) and NADPH dehydrogenase quinone 1 (NQO1). Furthermore, SF ($200{\mu}g/mg$) promoted the nuclear translocation of Nrf2. The SF-mediated reduction of lipid accumulation was associated with the regulation of the Nrf2/Keap1 pathway.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.17 no.3
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• pp.313-319
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• 2019

The A-KRS (Advanced Korean Reference Disposal System) is the disposal concept for pyroprocessed waste, which has been developed by the Korea Atomic Energy Research Institute. In this disposal concept, the amount of high-level radioactive waste is minimized using pyrochemical process, called pyroprocessing. The produced pyroprocessed waste is then solidified in the form of monazite ceramic. The final product of ceramic wastes will be disposed of in a deep geological repository. By the way, the decay heat is generated due to the radioactive decay of fission products and raises the temperature of buffer materials in the near field of radioactive waste repository. However, the buffer temperature must be kept below $100^{\circ}C$ according to the safety regulation. Usually, the temperature can be controlled by variation of the canister interdistance. However, KAERI has modelled thermal analysis under the boundary condition, where the waste canisters are in direct contact with each other. Therefore, a reliable temperature analysis in the disposal system may fail because of unknown thermal resistence values caused by the spatial gap between waste canisters. In the present work, we have performed thermal analyses considering the gap between heating elements and canisters at the beginning of canister loading into the radioactive waste repository. All thermal analyses were performed using the COMSOL software package.

• Journal of the Korean Data Analysis Society
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• v.20 no.6
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• pp.2907-2915
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• 2018

Journal of the Korean Data Analysis Society founded in 1998 has played the role of a major application journal. In this study, we checked the objective of this journal by checking the abstracts for 10 years. Abstract data was crawled from the online journal site (kdas.jems.or.kr) and analyzed by topic model. As a result, we found 18 topics from 2680 abstracts that had several contents, for example, nursing, marketing, economics, regression, factor analysis, data mining and statistical inferences. Topic1 (regression) is most frequent with 460 documents and we found the usefulness of regression in the applied science area. We confirmed the significant 10 association rules using by Fisher's exact test. Also, for exploring the trend of topics, we conducted the topic analysis for two periods which are 2006-2011 period and 2012-2016 period. We found that the control study was more frequent than survey study over time and regression and factor analysis were frequent regardless of time.

• Animal Bioscience
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• v.36 no.1
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• pp.43-52
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• 2023

Objective: This study aimed to examine the influence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection on pregnancy in cytokeratin-18 (K18)-hACE2 transgenic mice. Methods: To determine the expression of hACE2 mRNA in the female reproductive tract of K18-hACE2 mice, real-time polymerase chain reaction (RT-PCR) was performed using the ovary, oviduct, uterus, umbilical cord, and placenta. SARS-CoV-2 was inoculated intranasally (30 μL/mouse, 1×10⁴ TCID₅₀/mL) to plug-checked K18-hACE2 homozygous female mice at the pre-and post-implantation stages at 2.5 days post-coitum (dpc) and 15.5 dpc, respectively. The number of implantation sites was checked at 7.5 dpc, and the number of normally born pups was investigated at 20.5 dpc. Pregnancy outcomes, including implantation and childbirth, were confirmed by comparison with the non-infected group. Tissues of infected mice were collected at 7.5 dpc and 19.5 dpc to confirm the SARS-CoV-2 infection. The infection was identified by performing RT-PCR on the infected tissues and comparing them to the non-infected tissues. Results: hACE2 mRNA expression was confirmed in the female reproductive tract of the K18-hACE2 mice. Compared to the non-infected group, no significant difference in the number of implantation sites or normally born pups was found in the infected group. SARS-CoV-2 infection was detected in the lungs but not in the female reproductive system of infected K18-hACE2 mice. Conclusion: In K18-hACE2 mice, intranasal infection with SARS-CoV-2 did not induce implantation failure, preterm labor, or miscarriage. Although the viral infection was not detected in the uterus, placenta, or fetus, the infection of the lungs could induce problems in the reproductive system. However, lung infections were not related to pregnancy outcomes.

• The Korea Journal of Herbology
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• v.33 no.4
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• pp.101-108
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• 2018

Objectives : This study aimed to effects antioxidant activity of citrus peel extract (CPE) and effect on its glucose metabolism in L6 rat skeletal muscle cells. Methods : Antioxidative activities were evaluated by using 10 kinds of natural materials, and total polyphenol and flavonoid contents were examined. The L6 muscle cells toxicity of CPE was examined by MTT assay. Expression of glucose-related genes in L6 muscle cells by CPE treatment was analyzed by real-time PCR and western blotting. Results : The $IC_{50}$ values of DPPH and ABTS free radical scavenging activity of CPE were ($15.47{\pm}0.26{\mu}g/m{\ell}$ and $12.07{\pm}1.23{\mu}g/m{\ell}$, respectively), effectively clearing DPPH and ABTS. CPE showed total polyphenol and flavonoid contents ($20.30{\pm}0.38$ and $64.20{\pm}0.52$, respectively). The selected CPE were used in experiments using an effective concentration that is not toxic in L6 muscle cells. We investigated insulin receptor substrate-1 (IRS-1), phosphatidylinositol 3-kinase regulatory (PI3KR), Akt, and glucose transporter 4 (GLUT4). mRNA analysis by realtime PCR showed no significant difference, but CPE-treated cells showed a tendency to increase in concentration-dependent manner. However, analysis of protein expression of Akt and GLUT4 by western blotting showed that CPE treatment significantly increased concentration dependent (p<0.001). Conclusions : As a result, citrus peel extract with high antioxidant activity regulates glucose metabolism in L6 muscle cells. Therefore, CPE can be a potential treatment for the treatment of diabetes.

• The Journal of Engineering Geology
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• v.32 no.4
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• pp.437-448
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• 2022

This work aims to assess the threat to human health of hazardous materials in groundwater that is used domestically and for drinking. Two distinct sub-assessments are considered: cancer and non-cancer risk. The studied groundwater is in an agricultural area of Gyeongnam Province, Korea, and is contaminated by arsenic at a mean level of 16.27 ㎍/L, far greater than the WHO guideline (10 ㎍/L for drinking water). We collected groundwater data from the National Groundwater Information Center (gims.go.kr) and assessed the risk to human health following the methodology of the United States Environmental Protection Agency. We considered three exposure scenarios: domestic use (scenario 1) and drinking use with different doses (scenarios 2 and 3). Scenario 1 had a median hazard quotient (HQ) of 0.77 and a cancer risk (CR) of 0.013. Scenario 2 had a median HQ of 0.08 and a CR of 3.69 × 10^-5, and the values for scenario 3 were 0.11 and 4.82 × 10^-5, respectively. Scenario 1 is likely the most hazardous to human health. Further study of the origin of arsenic in groundwater in the study area is required, as are remedial measures to mitigate its health effects.