• International Journal of Industrial Entomology and Biomaterials
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• 제38권1호
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• pp.14-17
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• 2019

Oral gargling solution has been used for the control of halitosis. The purpose of this study was to compare the level of hydrogen sulphide concentration between silk oral gargling solution and commercially available oral gargling solution. Total 21 volunteers were included in this study. The relative level of hydrogen sulphide concentration was calculated to the baseline level. In terms of the primary endpoint of the trial, relative level of hydrogen sulphide concentration was $50.84{\pm}33.19%$ with silk group, versus $71.07{\pm}21.83%$ with Listerine group ($P_{non-inferiority}=0.003$). In conclusion, the results of oral gargling with a silk protein for healthy individual were non-inferior to oral gargling with Listerine for hydrogen sulphide concentration reduction.

• JSTS:Journal of Semiconductor Technology and Science
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• 제14권5호
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• pp.632-639
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• 2014

Mechanical stress and the vacuum level are the two main factors dominating the quality factor of a resonator operated in the vacuum range 1 mTorr to 10 Torr. This means that if the quality factor of a resonator is very insensitive to the mechanical stress in the vacuum range, it is sensitive to mainly the ambient vacuum level. In this paper, a wafer-level packaged MEMS resonator with a highly vacuum-sensitive quality factor is presented. The proposed device is characterized by a package with out-of-plane symmetry and a suspending structure with only a single anchor. Out-of-plane symmetry helps prevent deformation of the packaged device due to thermal mismatch, and a single-clamped structure facilitates constraint-free displacement. As a result, the proposed device is very insensitive to mechanical stress and is sensitive to mainly the ambient vacuum level. The average quality factors of the devices packaged under pressures of 50, 100, and 200 mTorr were 4987, 3415, and 2127, respectively. The results demonstrated the high controllability of the quality factor by vacuum adjustment. The mechanical robustness of the quality factor was confirmed by comparing the quality factors before and after high-temperature storage. Furthermore, through more than 50 days of monitoring, the stability of the quality factor was also certified.

• 농촌계획
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• 제13권2호
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• pp.85-92
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• 2007

This study aims to show how the urbanization of Korea has progressed for the last three decades, what its characteristics are, and how rural land use has changed by the national and district(cities and counties) level. The land use changes accompanying to the urbanization is analyzed through 3 indicators such as urbanization rate, the rate of cultivated and forest land and the rate of urbanized area. The statistical data are 30 years from 1976 to 2005 for time series analysis by the national level, and are for the two years of 1995 and 2005 by the district level. The relationship between urbanization and land use changes in the national level is analyzed using statistical analysis(Correlation Analysis). In order to analyze the dynamic and spatial urbanization and land use changes effectively in the district level, Z-score, Paired T-test, Correlation Analysis, Analysis of Variance and Chi-squire Test are used. The results show negative correlation between urbanization rate and the rate of cultivated and forest land, and positive correlation between urbanization rate and the rate of urbanized area respectively. In the aspect of the change of urbanization rate, four categories are examined. In addition, four types are characterized on the basis of the rate of cultivated and forest land and the rate of urbanized area between 1995 from 2005.

• 한국임상수의학회지
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• 제35권2호
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• pp.35-38
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• 2018

Recently assessment of suppression of tumorigenicity 2 (ST2) level has become a useful cardiac biomarker in human medicine. This study compared serum ST2 levels and N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels between healthy dogs and dogs with chronic mitral valve disease. Twenty client-owned dogs were investigated. Dogs were divided into normal, asymptomatic, and symptomatic groups. Serum samples were used to measure levels of NT-proBNP and ST2. Samples for NT-proBNP were sent to IDEXX laboratory for analysis while ST2 levels were measured by using a canine interleukin 33 receptor ELISA kit. There was a significant difference in NT-proBNP levels between asymptomatic and symptomatic groups (P < 0.01), and between normal and symptomatic groups (P < 0.01). In contrast, ST2 levels were not relatively different between asymptomatic and symptomatic groups (P > 0.05). There was no significant difference was observed among all groups in ST2 study. The usefulness of measuring NT-proBNP level as a cardiac biomarker in dogs with chronic mitral valve disease was confirmed, but usefulness of the ST2 level was not observed. Further investigations are needed to evaluate the potential usefulness of ST2 level as a cardiac biomarker in canines.

• Journal of Forest and Environmental Science
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• 제30권1호
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• pp.76-84
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• 2014

This study was performed to monitor the effects of water level change on changes of landscape, vegetation community, and species diversity of riparian forest. Hantan river dam, study area, has been constructed in the area of Chansoo-myeon, Pocheon-si and Yeoncheon-eup, Yeoncheon-gun, Gyeonggi-do, which is a dam for flood control only in flooding season. Landscape changes were notable after the construction of coffer dam, and the changes were caused by water level increase in areas of riparian forests which consisted of mainly withered willow as a dominant species in the flooding season. It changed vegetation communities of riparian forest from Phragmites japonica and Salix koreensis to Phragmites japonica. Species diversity index was lowest in 2010 when the coffer dam was constructed and showed an increasing trend later. Thus, this study is well in agreement with a previous report that plants of the genus Salix wither by muddy water during flooding and also suggests, controlling water level of river and prediction of water level change's effects should be considered when any facilities are planned.

• 전력전자학회논문지
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• 제19권4호
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• pp.376-382
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• 2014

This paper proposes the pulse width modulation (PWM) control strategy for low-speed operation in the three-level neutral-point-clamped (NPC) inverters based on the bootstrap gate drive circuit. As a purpose of the cost reduction, several papers have paid attention to the bootstrap circuit applied to the three-level NPC inverter. However, the bootstrap gate driver IC cannot generate the gate signal to the IGBT for low-speed operation, because the bootstrap capacitor voltage decreases under the threshold level. For low-speed operation, the dipolar and partial-dipolar modulations can be the effective solution. However, these modulations have drawbacks in terms of the switching loss and THD. Therefore, this paper proposes the PWM control strategy to operate the inverter at low-speed and to minimize the switching loss and harmonics. The experimental results are presented to verify the validity on the proposed method.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2019년도 춘계학술대회
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• pp.92-92
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• 2019

In this study, we evaluated the effect of branch (STB) and leave (STL) extracts from Sageretia thea on ${\beta}$-catenin level in human colorecal cancer cells, SW480 and lung cancer cells, A549. STB and STL dose-dependently suppressed the growth of SW480 and A549 cells. STB and STL decreased ${\beta}$-catenin level in both protein and mRNA level. MG132 decreased the downregulation of ${\beta}$-catenin protein level induced by STB and STL. However, the inhibition of $GSK3{\beta}$ by LiCl or ROS scavenging by NAC did not block the reduction of ${\beta}$-catenin protein by STB and STL. Our results suggested that STB and STL may downregulate ${\beta}$-catenin protein level independent on $GSK3{\beta}$ and ROS. Based on these findings, STB and STL may be a potential candidate for the development of chemopreventive or therapeutic agents for human colorectal cancer and lung cancer.

• 방사성폐기물학회지
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• 제20권1호
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• pp.127-131
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• 2022

The structural safety of prototype transport and storage containers for very low-level radioactive liquid waste was experimentally estimated for its localization development. Transport containers for radioactive liquid waste have been researched and developed, however, there are no standardized commercial containers for very low-level radioactive waste in Korea. In this study, the structural safety of the designated IP-2 type container capable of transporting and temporarily storing large amounts of very low-level liquid waste, which is generated during the operation and decommissioning of nuclear power plants, was demonstrated. The stacking and drop tests, which were conducted to determine the structural integrity of the container, verified that there was no external leakage of the contents in spite of its structural deformation due to the drop impact. This study shows the effort required for the localization of the technology used in manufacturing transport and storage containers for very low-level radioactive liquid waste, and the additional structural reinforcement of the container in which the commercial intermediate bulk container (IBC) external frame was coupled.

• 대한한의학회지
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• 제42권3호
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• pp.86-98
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• 2021

Objectives: This study aims to evaluate the impact of patient-physician communication curriculum on students of Korean medical school in terms of cognitive, affective, and psychomotor level of communication skills. Methods: A communication curriculum was developed considering COVID-19 pandemic situation. Lectures, peer role-play, open interview with standardized patient (SP), discussion and feedback were conducted by online, and face-to-face 1:1 SP-interview was performed. Scores of written test, peer role-play of medical communication, SP-interview, self-evaluation on one's interview with real patients in clinical clerkship, and questionnaire of importance were collected and analyzed. Results: Converted to 100 point scale, the mean score of written test (cognitive level) was 91.2 while that of importance questionnaire (affective level) was 77.5. The mean scores of psychomotor level were 72.5, 77.5, and 62.5 for peer role-play, SP-interview, and real patient interview in clerkship, respectively. Conclusions: Students' performance is lower in higher level of competence. Curriculums should provide more opportunities of practices to students, and include evaluation focusing on performance skills.

• 한국수산과학회지
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• 제56권6호
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• pp.899-908
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• 2023

Droughts can alter the dynamics of aquatic ecosystems, including fish communities. This study compared the variations in fish communities in Juam reservoir before and after drought events. Fish sampling was conducted five times from April 2021 to April 2023 using three different sampling methods (kick net, cast net, and gill net). The water level in the reservoir reached its peak (103.73 EL.m, 62.2% capacity) in September 2021, before the drought, and dropped to its lowest point (88.84 EL.m, 17.6% capacity) in April 2023. The dissolved oxygen content in the reservoir decreased from 27 to 6.3 mg/L between the period with the lowest water level (April 2023) and the period with the highest water level (September 2021). In September 2021, 466 fish were collected, but after one year of drought, the number of individuals decreased to 105. Further, the number of fish collected and water levels were positively correlated. Dominant species exhibited a population decline of over 60% with decreasing water levels. These findings highlight the importance of fishery resource management during drought periods.