• Journal of Korean Neurosurgical Society
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• v.63 no.1
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• pp.34-44
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• 2020

Objective : Despite widespread use of flow diverters (FDs) to treat aneurysms, the exact healing mechanism associated with FDs remains poorly understood. We aim to describe the healing process of aneurysms treated using FDs by demonstrating the histopathologic progression in a canine aneurysm model. Methods : Twenty-one side wall aneurysms were created in common carotid artery of eight dogs and treated with two different FDs. Angiographic follow-ups were done immediately after placement of the device, 4 weeks and 12 weeks. At last follow-up, the aneurysm and the device-implanted parent artery were harvested. Results : Histopathologic findings of aneurysms at 4 weeks follow-up showed intra-aneurysm thrombus formation in laminating fashion, and neointimal thickening at the mid-segment of aneurysm. However, there are inhomogenous findings in aneurysms treated with the same type of FD showing same angiographic outcomes. At 12 weeks, aneurysms of complete and near-complete occlusion revealed markedly shrunken aneurysm filled with organized connective tissues with thin neointima. Aneurysms of incomplete occlusion at 12 weeks showed small amount of organized thrombus around fringe neck and large empty space with thick neointmal formation. Neointimal thickness and diameter stenosis was not significantly different between the groups of FD specification and follow-up period. Conclusion : Intra-aneurysmal thrombus formation and organization seem to be an important factor for the complete occlusion of aneurysms treated using the FD. Neointimal formation could occur along the struts of the FD independently of intra-aneurysmal thrombus formation. However, neointimal formation could not solely lead to complete aneurysm healing.

• Korean Journal of Construction Engineering and Management
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• v.21 no.2
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• pp.15-21
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• 2020

The relationship between keywords, found in all productivity related papers published in the KSCE journal for last 15 years, were analyzed in order to reveal a research trend in the area using text mining and A-Priori algorithm. As the results, it is found that the word of 'productivity' is most closely related to the words of 'work' and 'labor'. Futhermore, the word is somewhat related to those of 'factor', 'model', simulation', and 'work time'. It is also revealed that, on the other hand, the words of 'machine' and 'equipment' have little relationships with the keyword. This research will be a great help for academia to understand a research trend in the area of construction productivity.

• Journal of Environmental Science International
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• v.29 no.1
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• pp.1-13
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• 2020

Recently, a heavy rainfall with high spatial variation occurred frequently in the Korean Peninsula. The meteorological event that occurred in Busan on 3 May 2016 is characterized by heavy rain in a limited area. In order to clarify the reason of large spatial variation associated with mountain height and location of low level jet, several numerical experiments were carried out using the dynamic meteorological Weather Research and Forecasting (WRF) model. In this case study, the raised topography of Mount Geumjeong increased a barrier effect and air uplifting due to topographic forcing on the windward side. As a result, wind speed reduced and precipitation increased. In contrast, on the downwind side, the wind speed was slightly faster and since the total amount of water vapor is limited, the precipitation on the downwind side reduced. Numerical experiments on shifting the location of the lower jet demonstrated that if the lower jet is close to the mountain, its core becomes higher due to the effect of friction. Additionally, the water vapor convergence around the mountain increased and eventually the precipitation also increased in the area near the mountain. Hence, the location information of the lower jet is an important factor for accurately predicting precipitation.

• Journal of Preventive Medicine and Public Health
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• v.53 no.1
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• pp.56-63
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• 2020

Objectives: The objective of this study was to determine the effect of atrial fibrillation (AF) on the risk of dementia in the Korean elderly. Methods: A 10-year retrospective cohort study was conducted using the National Health Insurance Service-Senior Cohort database. We excluded those who were under 65 years of age as of January 2006 (n=46 113), those who were diagnosed with dementia between 2002 and 2005 (n=9086), and those with a history of stroke prior to AF diagnosis (n=8392). We used a Cox proportional hazards model with a time-varying covariate to determine whether AF is associated with the risk of dementia after adjusting for potential confounders. Results: In univariable Cox regression, the hazard ratio (HR) of dementia according to AF status was 1.28 (95% confidence interval [CI], 1.23 to 1.33). After adjusting for potential confounders, AF was found to increase the risk of dementia (HR, 1.12; 95% CI, 1.07 to 1.17), Alzheimer dementia (HR, 1.12; 95% CI, 1.07 to 1.17), and vascular dementia (HR, 1.10; 95% CI, 1.03 to 1.18). In patients diagnosed with AF, the incidence of dementia was lower (HR, 0.50; 95% CI, 0.47 to 0.52) in patients who were treated with oral anticoagulants. Conclusions: Investigating the potential risk factors of dementia in an aged society is important. We found a slightly higher risk of dementia in those with AF than in those without AF, and we therefore concluded that AF is a potential risk factor for dementia.

• Structural Engineering and Mechanics
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• v.63 no.6
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• pp.713-723
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• 2017

As a new type of ballastless track, longitudinal continuous slab track (CST) has been widely used in China. It can partly isolate the interaction between the ballastless track and the bridge and thus the rail expansion device would be unnecessary. Compared with the traditional track, CST is composed of multi layers of continuous structures and various connecting components. In order to investigate the performance of CST on a long-span bridge, the spatial finite element model considering each layer of the CST structure, connecting components, bridge, and subgrade is established and verified according to the theory of beam-rail interaction. The nonlinear resistance of materials between multilayer track structures is measured by experiments, while the temperature gradients of the bridge and CST are based on the long-term measured data. This study compares the force distribution rules of ballasted track and CST as respectively applied to a long span bridge. The effects of different damage conditions on CST structures are also discussed. The results show that the additional rail stress is small and the CST structure has a high safety factor under the measured temperature load. The rail expansion device can be cancelled when CST is adopted on the long span bridge. Beam end rotation caused by temperature gradient and vertical load will have a significant effect on the rail stress of CST. The additional flexure stress should be considered with the additional expansion stress simultaneously when the rail stress of CST requires to be checked. Both the maximum sliding friction coefficient of sliding layer and cracking condition of concrete plate should be considered to decide the arrangement of connecting components and the ultimate expansion span of the bridge when adopting CST.

• Human Ecology Research
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• v.55 no.5
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• pp.507-526
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• 2017

To infer the true state of a regional product's attributes, consumers use the image they have of the product's region of origin; however, products may have multiple countries of origin in their design, branding, sourcing and manufacturing becuase more products are increasingly a result of multi-firm and multi-country efforts. We examined how the country-of-origin image (country image and product image) affect international consumers' perceived value (function value and symbolic value) and purchase intentions of made-in China goods by extending and deepening the flexible model. Second, to investigate the differences of COO effects according to different types of country-of-origin we divided the traditional country-of-origin into two components: country-of-manufacture (COM) and country-of-brand (COB). We then explore how the impact of China's country image on consumers' perceived value and purchase intentions varies when China is the COM or COB of the same product. Six hypotheses were proposed to test our anticipations. We recruited 800 Korean adult consumers who previously purchased made-in China products to participate in the online investigation. Data analyses were conducted with confirmatory factor analysis and structural equation modeling using SPSS and AMOS. The main results are discussed as follows. First, the effects of China's COO image on Korean consumers' perceived value and purchase intentions vary when China is the COM or COB of a product. Second, a positive effect of the function value and symbolic value on the purchase intentions was found. Literature and practical implications of findings are discussed and suggested in the conclusion.

• Korean Journal of Acupuncture
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• v.34 no.3
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• pp.146-155
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• 2017

Objectives : This study was carried out to investigate the effects of Crataegi Fructus water extract(CFWE) on hair growth in an alopecia model of C57BL/6N mice and human dermal papilla cells(hDPCs). Methods : Six-week old mice were depilated and separated in 3 groups ; CON, MXD(2% Minoxidil), and CFWE. The treatments were applied twice a day for 18 days. The hair growth was determined photographically. The hair density, thickness and length were identified by Folliscope and the weights of body were measured. In dorsal skin tissue, the expression of hair growth-related protein was analyzed by Western blot. In hDPCs with/without $IFN-{\gamma}$, cell proliferation and the expression of hair growth-related genes were analyzed. Results : We observed that CFWE promoted hair growth compared to CON. CFWE improved the hair density, thickness and length compared to CON. CFWE increased the $Wnt/{\beta}$-catenin signaling in dorsal skin. In hDPCs, CFWE accelerated the cell proliferation and inhibited $IFN-{\gamma}$-induced hDPCs degeneration. CFWE increased the mRNA expression of ${\beta}$-catenin, Axin-2, BMP-4, FGF-7, FGF-10, and ALP compared to CON and $IFN-{\gamma}$ treated cells. Conclusions : These results suggest that CFWE has a hair regrowth activity via $Wnt/{\beta}$-catenin signaling and can be useful for the treatment of alopecia.

• Journal of Digital Convergence
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• v.15 no.11
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• pp.523-534
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• 2017

The purpose of this study was to examine the effects of social bonding on self-competence in the juvenile delinquency on the mediating effect of self-esteem. The data of 908 juvenile inmates in a Study on Measures to Develop Entrepreneurship Education Model and to Encourage Start-up for Youth(2015) by the National Youth Policy Institute were analysed. The results of the study are: (1) social bonding was found a key factor affecting the self-competence, (2) their social bonding affects self-esteem, (3) self-esteem affects self-competence, (4) self-esteem was proved to have a mediating effect between the effects of social bonding and self-competence. The implications and limitations are reviewed, as are the suggestions for future research.

• Journal of Digital Convergence
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• v.15 no.11
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• pp.155-165
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• 2017

This study divides organizational citizenship behaviors into two dimensions, organizational and individual, in order to clarify the out-role behaviors of organizational members more specifically. In addition, we selected Empowering leadership as an input factor that can lead to organizational citizenship behavior and examined the mediating role of trust. To accomplish this purpose, the authors conducted a survey of employees in manufacturing companies in the Daegu-Gyeongbuk region and the hypothesis was verified through structural equations model. The results of the study are as follows. Empowering leadership has a significant positive impact on OCB-O and OCB-I. Also, Trust has been found to partial mediate effect the relationship between empowering leadership and OCB_O and OCB_I. The results of this study will be specific guidelines for inducing organizational citizenship behavior in organizations, and will further expand the scope of research into organizational citizenship behavior.

• Journal of Chest Surgery
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• v.51 no.2
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• pp.114-121
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• 2018

Background: Unfractionated heparin is commonly used for anticoagulation in extracorporeal membrane oxygenation (ECMO). Several studies have shown that nafamostat mesilate (NM) has comparable clinical outcomes to unfractionated heparin. This study compared anticoagulation with NM and heparin in a large-animal model. Methods: Beagle dogs (n=8; weight, 6.5-9 kg) were placed on venovenous ECMO. Blood samples were taken every hour and the following parameters were compared: hemoglobin level, activated partial thromboplastin time (aPTT), thromboelastography (TEG) data, platelet function, and inflammatory cytokine levels. Results: In both groups, the aPTT was longer than the baseline value. Although the aPTT in the NM group was shorter than in the heparin group, the TEG parameters were similar between the 2 groups. Hemoglobin levels decreased in both groups, but the decrease was less with NM than with heparin (p=0.049). Interleukin $(IL)-1{\beta}$ levels significantly decreased in the NM group (p=0.01), but there was no difference in the levels of tumor necrosis factor alpha or IL-10 between the 2 groups. Conclusion: NM showed a similar anticoagulant effect to that of unfractionated heparin, with fewer bleeding complications. NM also had anti-inflammatory properties during ECMO. Based on this preclinical study, NM may be a good alternative candidate for anticoagulation in ECMO.