• Tunnel and Underground Space
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• v.29 no.4
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• pp.262-279
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• 2019

In the engineering barriers of high-level radioactive waste disposal, gases could be generated through a number of processes. If the gas production rate exceeds the gas diffusion rate, the pressure of the gas increases and gases could migrate through the bentonite buffer. Because people and the environment can be exposed to radioactivity, it is very important to clarify gas migration in terms of long-term integrity of the engineered barrier system. In particular, it is necessary to identify the hydro-mechanical mechanism for the dilation flow, which is a very important gas flow phenomenon only in medium containing large amounts of clay materials such as bentonite buffer, and to develop and validate new numerical approach for the quantitative evaluation of the gas migration phenomenon. Therefore, in this study, we developed a two-phase flow model considering the mechanical damage model in order to simulate the gas migration in the engineered barrier system, and validated with 1D gas flow modelling through saturated bentonite under constant volume boundary conditions. As a result of numerical analysis, the rapid increase in pore water pressure, stress, and gas outflow could be simulated when the dilation flow was occurred.

• Journal of Convergence for Information Technology
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• v.9 no.5
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• pp.55-64
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• 2019

The purpose of this study was to investigate levels of self-efficacy, nurse image, vocational identity, and clinical practice satisfaction, to examine relationships among them, and finally to investigate predictors affecting of clinical practice satisfaction in nursing students. The participants were 227 nursing students in D city who were surveyed in September 2018 using self-report questionnaires. Self-efficacy, nurse image, vocational identity, and clinical practice satisfaction were related positively among variables. In the multiple regression analysis, self-efficacy, nurse image, vocational identity, health condition, relationship with practical colleague and 'satisfaction of nursing students in patient's recognition of nursing students' were influential factors significantly associated with the clinical practice satisfaction. Those factors explained 17.9% of the clinical practice satisfaction of nursing students. The most important factors were 'satisfaction of nursing students in patient's recognition of nursing students' and nurse image. In order to improve clinical practice satisfaction of nursing students, whole nurses should consider helping nursing students and patients to build up positive nurse image.

• Journal of Microbiology and Biotechnology
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• v.31 no.7
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• pp.933-941
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• 2021

Ginsenoside Rg4 is a rare ginsenoside that is naturally found in ginseng, and exhibits a wide range of biological activities including antioxidant and anti-inflammatory properties in several cell types. The purpose of this study was to use an in vivo model of hair follicle (HF)-mimic based on a human dermal papilla (DP) spheroid system prepared by three-dimensional (3D) culture and to investigate the effect of Rg4 on the hair-inductive properties of DP cells. Treatment of the DP spheroids with Rg4 (20 to 50 ㎍/ml) significantly increased the viability and size of the DP spheres in a dose-dependent manner. Rg4 also increased the mRNA and protein expression of DP signature genes that are related to hair growth including ALP, BMP2, and VCAN in the DP spheres. Analysis of the signaling molecules and luciferase reporter assays further revealed that Rg4 induces the activation of phosphoinositide 3-kinase (PI3K)/AKT and the inhibitory phosphorylation of GSK3β, which activates the WNT/β-catenin signaling pathway. These results correlated with not only the increased nuclear translocation of β-catenin following the treatment of the DP spheres with Rg4 but also the significant elevation of mRNA expression of the downstream target genes of the WNT/β-catenin pathway including WNT5A, β-catenin, and LEF1. In conclusion, these results demonstrated that ginsenoside Rg4 promotes the hair-inductive properties of DP cells by activating the AKT/GSK3β/β-catenin signaling pathway in DP spheres, suggesting that Rg4 could be a potential natural therapy for hair growth.

• Journal of the Korean Society of Radiology
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• v.13 no.5
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• pp.721-728
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• 2019

The purpose of this study was to evaluate the relationship between bone mineral density (BMD) and body composition (BC) or backmuscle strength (BS). Sixty-one participants were measured by BMD using ultrasound bone densitometry and Inbody for BC (i.e., SLM=Soft lean mass, SMM=Skeletal muscle mass, FS=Fitness score. et al.), BS after self-questionnaire for life cycle. This study was performed after approving Institutional Review Board and obtaining the informed concent from all participants. Participants was divided into two group by BMD T-score; $T-score{\geq}-1.0$, T-score<-1.0. Statistical analysis was performed by using SPSS ver. 22.0(USA), Spearma test for correlation between BMD and BC or BS. BMD or SLM, BS was increased with increasing physical activity or body mass index. SMM or SMM, FS of BMD $T-score{\geq}-1.0$ group was higher than that of T-score <-1.0 group as well as BS(p>0.05). BMD T-score was correlated positively with SLM(r= 0.424) or SMM(r= 0.431) in men, as well as in women(p<0.05). BS was correlated positively with SLM or SMM, FS. BS was significantly positive correlated with BMD in women group (r= 0.591, p= 0.001), but not in men group. We concluded that BMD is the relationship with SLM or SMM, as well as BS in women.

• Obstetrics & gynecology science
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• v.61 no.6
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• pp.662-668
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• 2018

Objective This study was to identify the risk factors for cytological progression in women with atypical squamous cells of undetermined significance (ASC-US) or low-grade squamous intraepithelial lesions (LSIL). Methods We analyzed data from women infected with the human papillomavirus (HPV) who participated in the Korean HPV cohort study. The cohort recruited women aged 20-60 years with abnormal cervical cytology (ASC-US or LSIL) from April 2010. All women were followed-up at every 6-month intervals with cervical cytology and HPV DNA testing. Results Of the 1,158 women included, 654 (56.5%) and 504 (43.5%) women showed ASC-US and LSIL, respectively. At the time of enrollment, 143 women tested positive for HPV 16 (85 single and 58 multiple infections). Cervical cytology performed in the HPV 16-positive women showed progression in 27%, no change in 23%, and regression in 50% of the women at the six-month follow-up. The progression rate associated with HPV 16 infection was higher than that with infection caused by other HPV types (relative risk [RR], 1.75; 95% confidence interval [CI], 1.08-2.84; P=0.028). The cytological progression rate in women with persistent HPV 16 infection was higher than that in women with incidental or cleared infections (P<0.001). Logistic regression analysis showed a significant relationship between cigarette smoking and cytological progression (RR, 4.15; 95% CI, 1.01-17.00). Conclusion The cytological progression rate in HPV 16-positive women with ASC-US or LSIL is higher than that in women infected with other HPV types. Additionally, cigarette smoking may play a role in cytological progression.

• Korean Journal of Labor Studies
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• v.19 no.1
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• pp.1-34
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• 2013

Labor share of income in Korea has fallen from 90% in 1996 to 79% in 2010. This paper explores the factors driving the movements in the labor share of income based on a panel dataset containing 19 years of data on 18 Korean manufacturing industries. The effects of technical progress, globalization and the bargaining power of labor and capital on the labor share of income are tested for the period of 1991-2009. The main empirical results are as follows. (1) Capital-aug menting technical prog ress measured by capital-labor ratio and R&D intensity has a negative effect on the labor share. (2) Market openness measured by the value of export and import as a ratio to value-added production is found to have a positive impact. (3) Globalization of production measured by inward-FDI and outward-FDI as a ratio to total domestic fixed capital is found to have a negative impact on the labor share. (4) Union density is found to have had a statistically significant effect in 1991-1998. This finding is consistent with the efficient bargain model in which firms and workers bargain over both wages and employment. But union density is insignificant in 2000-2009. This implies that since the financial crisis in 1997, the bargaining institution in Korea has been approaching the right-to-manage model in which firms and unions bargain over wages and then firms set employment unilaterally. (5) Variables for domestic financialization measured by dividend-income ratio and financial-fixed assets ratio have an insignificant effect on labor share.

• Journal of Practical Agriculture & Fisheries Research
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• v.23 no.1
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• pp.117-128
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• 2021

The skeletal muscle development of Hanwoo steer has been processed in the prenatal and postnatal periods. Bovine satellite cell located in perimysium of muscle tissues has differentially distributed in peripheral tissues. The study of postnatal development of satellite cells can help understand the genetic and functional regulation of meat characteristics. Factors affecting muscle size increase are related to the accumulation of DNA or synthesis of RNA proteins. In this study, we observed muscle development and differentiation after culturing bovine satellite cells derived from longissimus dorsi and semimembranosus regions of Hanwoo muscle tissue. In addition, RNA sequencing data were analyzed for differentially expressed genes (DEG) involved in intracellular muscle development and growth. The DEG of the two muscle tissues were compared according to 1day, 2day, 4day, and 7day. The overall gene expression level was confirmed by the heat map. Gene Ontology (GO) classification method was used to compare the expression level of gene groups affecting LD and SM development. The histology of GO was consistent with the time-cause change of LD and SM cell morphology. SM showed more active skeletal muscle development than LD. Even within the same time, SM expressed more genes than LD, thus synthesizing more muscle fibers

• Geomechanics and Engineering
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• v.28 no.3
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• pp.299-311
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• 2022

Water-resisting key stratum (WKS) between coal seams is an important barrier that prevents water inrush from goaf in roof under multi-seam mining. The occurrence of water inrush can be evaluated effectively by analyzing the fracture of WKS in multi-seam mining. A "long beam" water inrush mechanical model was established using the multi-seam mining of No. 2+3 and No. 8 coal seams in Xiqu Mine as the research basis. The model comprehensively considers the pressure from goaf, the gravity of overburden rock, the gravity of accumulated water, and the constraint conditions. The stress distribution expression of the WKS was obtained under different mining distances in No. 8 coal seam. The criterion of breakage at any point of the WKS was obtained by introducing linear Mohr strength theory. By using the mechanical model, the fracture of the WKS in Xiqu Mine was examined and its breaking position was calculated. And the risk of water inrush was also evaluated. Moreover, breaking process of the WKS was reproduced with Flac3D numerical software, and was analyzed with on-site microseismic monitoring data. The results showed that when the coal face of No. 8 coal seam in Xiqu Mine advances to about 80 m ~ 100 m, the WKS is stretched and broken at the position of 60 m ~ 70 m away from the open-off cut, increasing the risk of water inrush from goaf in roof. This finding matched the result of microseismic analysis, confirming the reliability of the water inrush mechanical model. This study therefore provides a theoretical basis for the prevention of water inrush from goaf in roof in Xiqu Mine. It also provides a method for evaluating and monitoring water inrush from goaf in roof.

• Journal of Veterinary Science
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• v.21 no.5
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• pp.77.1-77.14
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• 2020

Background: Staphylococcus aureus is one of the main microorganisms that causes bovine mastitis, and its well-known virulence characteristics and interactions with the environment are used to aid the design of more efficient therapies. Objectives: To determine whether the virulence traits, such as antibiotic resistance and biofilm-forming and internalization abilities, of S. aureus isolated from bovine mastitis are related to dairy production system types. Methods: The study was performed in the Mexican states of Guanajuato and Michoacan. Semi-intensive dairy farms (SIDFs) and family dairy farms (FDFs) (454 and 363 cows, respectively) were included. The 194 milk samples from mastitis affected quarters were collected and 92 strains of S. aureus were isolated and identified by biochemical and molecular tests. Antibiotic resistance, biofilm and internalization assays were performed on 30 randomly selected isolated strains to determine virulence traits, and these strains were equally allocated to the 2 dairy production systems. Results: All 30 selected strains displayed a high degree of resistance (50%-91.7%) to the antibiotics tested, but no significant difference was found between SIDF and FDF isolates. S. aureus strains from SIDFs had an average biofilm forming capacity of up to 36% (18.9%-53.1%), while S. aureus strains from FDFs registered an average of up to 53% (31.5%-77.8%) (p > 0.05). Internalization assays revealed a higher frequency of internalization capacity for strains isolated from FDFs (33.3%) than for those isolated from SIDFs (6.7%) (p > 0.05). fnbpA gen was detected in 46.6% of FDF strains and 33.3% of SIDF strains, and this difference was significant (p < 0.05). Conclusions: Our findings show that the virulence traits of S. aureus isolates analyzed in this study, depend significantly on several factors, such as phenotype, genotype, and environmental conditions, which are significantly related to dairy production system type and daily management practices.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.514-514
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• 2023

댐 건설은 하천의 유황, 유사량을 변화시켜 이·치수 및 생태계에 영향을 미치고 있다. 그러나 현재 댐 운영에 사용하고 있는 하천 기본계획은 10년마다 수립하고 있어 하천 지형 측량자료, 식생 및 수생태를 고려한 하천 관리 계획은 대부분 과거자료이다. 또한 홍수소통에 영향을 미치는 하도식생에 대한 연구가 거의 없어 최근 기후변화로 인해 빈번하게 발생하는 홍수 등 물재해에 적극적 대응이 어려운 실정이다. 따라서 최신의 하천 기초조사 자료 기반, '20년 댐 하류하천에 홍수가 발생한 4개 댐(대청, 합천, 용담, 섬진강댐)을 대상으로 하상변동, 식생 영향 등을 고려한 댐 직하류 하천관리방안을 마련하는 연구를 진행하였다. 최신 하천 기초조사 자료 확보를 위해 하천기본계획 등 문헌정보를 수집하고 댐 직하류의 수중부·육상부 측량, 유사량·하상재료 조사, 식생조사, 홍수흔적조사 등을 실시하였다. 확보한 기초자료를 바탕으로 하상변동 분석 모델 및 물리적 서식처 모의 모델을 통해 이수, 치수, 생태 측면으로 분석을 진행하였다. 이수 분석으로 HEC-RAS의 유사이송 분석을 통해 현재부터 20년 뒤의 하상변동을 분석하였다. 치수 분석으로 HEC-RAS 2D 등의 유사이송 분석을 사용하여 한 개의 홍수기 사상 발생 시 하상변동을 분석하였으며, 식생의 유무가 하상변동에 미치는 영향을 함께 분석하였다. 생태 분석으로는 PHABSIM을 사용하여 대상어종에 대한 하상변동 및 식생 유무에 따른 환경생태영향의 영향을 분석하였다. 분석을 바탕으로 각 대상 댐 직하류에 이수, 치수, 생태 측면의 하천관리방안을 수립하였다. 이수 분석을 통해 20년 뒤의 취양수장의 제약수위를 예측, 검토하고 취약구간 모니터링 구간을 산정하였다. 또한 침식과 퇴적이 크게 일어나는 구간을 산정하여 장·단기 하상변동 모니터링 구간을 제시하였다. 치수 분석을 통해 식생이 댐 하류에 미치는 영향을 분석하여 식생 저감 구간을 선정하는 등 적정 식생 밀도 조절 방안을 제시하였다. 또한 하상변동량이 큰 구간은 하상 안정 유지를 위한 수제 설치를 모델 결과를 통해 검토하였으며 제방 정비가 필요한 구간은 드론을 활용한 모니터링을 제안하였다. 생태 분석을 통해 대상 어종이 서식하기 가장 적합한 환경생태유량을 산정하고 댐 하류 하천의 자연성 회복을 위한 증가방류, 유사환원 등의 방안을 검토하였다.