• Archives of Pharmacal Research
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• 제22권1호
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• pp.35-43
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• 1999

Overstimulation of both kainate (KA) and N-methyl-D-aspartate (NMDA) receptors has been reported to induce excitatoxicity which can be characterized by neuronal damage and formation of reactive oxygen free radicals. Neuroprotective effect of melatonin against KA-induced excitotoxicity have been documented in vitro and in vivo. It is, however, not clear whether melationin is also neuroportective against excitotoxicity mediated by NMDA receptors. In the present work, we tested the in vivo protective effects of striatally infused melatonin against the oxidative stress and neuronal damage induced by the injection of KA and NMDA receptors into the rat striatum. Melatonin implants consisting of 22-gauge stainless-steel cannule with melatonin fused inside the tip were placed bilaterally in the rat brain one week prior to intrastriatal injection of glutamate receptor subtype agonists. Melatonin showed protective effects against the elevation of lipid peroxidation induced by either KA or NMDA and recovered Cu, Zn-superoxide dismutase activities reduced by both KA and NMDA into the control level. Melatonin also clearly blocked both KA- and NMDA-receptor mediated neuronal damage assessed by the determination of choline acetyltransferase activity in striatal monogenages and by microscopic observation of rat brain section stained with cresyl violet. The protective effects of melatonin are comparable to those of DNQX and MK801 which are the KA- and NMDA-receptor antagonist, respectively. It is suggested that melatonin could protect against striatal oxidative damages mediated by glutamate receptors, both non-NMDA and NMDA receptors.

• Spatial Information Research
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• 제17권3호
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• pp.351-359
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• 2009

최근 수심측량 기술은 단일빔음향측심기에서 발달된 다중빔음향측심기가 일반화되면서 우리나라에 인접한 바다와 내륙에 형성된 하천 지역에 대한 정확한 수심측량 및 지형조사에 다중빔음향측심기가 사용되고 있다. 본 연구에서는 현재 널리 사용되고 있는 다중빔음향측심기의 정확도를 검증하고 정확도를 향상시킬 수 있는 검증방법을 수립하기 위해, 외력(파도, 조류 조석)에 의한 영향이 상대적으로 작은 하천지역에서 취득된 데이터의 정확도 분석을 실시하였다. 동일한 위치에서 토탈스테이션과 수위계를 이용하여 취득된 자료를 통해 정확도를 검증한 후 IHO의 허용오차 기준에 부합되는 지 여부를 판단하였다. 분석결과, 수심이 깊을수록 다중빔음향측심기의 측심 오차가 미세하게 증대되는 것으로 나타났으나, IHO 허용오차를 기준으로 특급 성과의 획득은 가능한 것으로 판단된다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.216-219
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• 2005

In precision length measurements using optical interferometry based on homodyne or heterodyne principles, it is crucial to have frequency-stabilized monochromatic light sources. To the end, we investigate the possibility of utilizing the optical comb constituted by ultrashort femtosecond pulse lasers generated from a gain medium of titanium-doped aluminium oxide $(Ti:Al_2O_3)$. The optical comb is stabilized by locking to the caesium atomic clock, which allows all the modes of the comb to maintain an extremely high level of frequency stabilization to precision of one part in $10^{16}$. Then, high precision length measurements are realized by extracting a single or group of particularly wanted optical frequency components or by adopting a third-party light source locked to the comb. Required measurement system setup will be presented in detail along with experimental results.

• 보건행정학회지
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• 제28권1호
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• pp.98-103
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• 2018

This study aims to evaluate the status of Korean healthcare among Organization for Economic Cooperation and Development countries and to monitor the trend of health care status since 2000. The position value for relative comparison (PARC) index was selected to gauge the level of healthcare status in demand, supply, accessibility, quality, and cost as per healthcare policy aspects. The Mann-Kendall test was conducted to allocate healthcare status of Korea since 2000. The PARC values indicate strength and weakness of Korean healthcare system by the mathematical comparisons. Korea positioned higher in demand, supply, accessibility, and quality. Yet, there are shortages in human resources and primary care. In conclusion, we suggest utilizing this study provides evidence to prioritize health care problems that can lead to establishing healthcare policy.

• 한국가정과학회지
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• 제9권4호
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• pp.55-66
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• 2006

The purpose of this study was to identify the effect on the evaluation or a female teachers' role-performance based on appearance according to backgrounds of students and their parents. For this study, data was collected between October 19 and 29, 2005 by means of a questionnaire designed to gauge a subject's evaluation of a teacher's abilities in learning guidance, living guidance, and human relations. The researchers selected two middle schools and four high schools in the city of Gwang-ju. The 398 surveys completed were analyzed using factor analysis, one-way ANOVA, Duncan's multiple range test, t-test and descriptive statistics. According to the study, the evaluation of a female teacher's abilities varies with the backgrounds of both students and their parents. Among the students tested perceptions were affected by gender, grade level and type of school attended. For mothers there were differences based on age, occupation and family income.

• Steel and Composite Structures
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• 제43권4호
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• pp.483-500
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• 2022

Cold-formed steel wall panels sheathed with gypsum plasterboard have shown superior thermal and structural performance in fire. Recent damage caused by fire events in Australia has increased the need for accurate fire resistance ratings of wall systems used in low- and mid-rise construction. Past fire research has mostly focused on light gauge steel framed (LSF) walls under uniform axial compression and LSF floors under pure bending. However, in reality, LSF wall studs may be subject to both compression and bending actions due to eccentric loading at the wall to-roof or wall-to-floor connections. In order to investigate the fire resistance of LSF walls under the effects of these loading eccentricities, four full-scale standard fire tests were conducted on 3 m × 3 m LSF wall specimens lined with two 16 mm gypsum plasterboards under different combinations of axial compression and lateral load ratios. The findings show that the loading eccentricity can adversely affect the fire resistance level of the LSF wall depending on the magnitude of the eccentricity, the resultant compressive stresses in the hot and cold flanges of the wall studs caused by combined loading and the temperatures of the hot and cold flanges of the studs. Structural fire designers should consider the effects of loading eccentricity in the design of LSF walls to eliminate their potential failures in fire.

• Nuclear Engineering and Technology
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• 제54권11호
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• pp.4296-4309
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• 2022

Mesh and turbulence model sensitivity analyses have been performed on computational fluid dynamics simulations executed with Hydra and ANSYS Fluent for a single CANadian Deuterium Uranium (CANDU) 37M nuclear fuel bundle placed within a standard pressure tube. The goal of this work was to perform a methodical analysis to objectively determine an appropriate mesh and to gauge the sensitivity of different turbulence models for CANDU subchannel flow under isothermal conditions. The boundary conditions and material properties are representative of normal operating conditions in a high-powered channel of the Darlington Nuclear Generating Station. Four meshes were generated with ANSYS Workbench Meshing, ranging from 22 to 84 million cells, and analyzed here to determine an appropriate level of mesh resolution and quality. Five turbulence models were compared in the turbulence model sensitivity analysis: standard k - ε, RNG k - ε, realizable k - ε, SST k - ω, and the Reynolds Stress Model. The intent of this work was to gain confidence in mesh generation and turbulence model selection of a single bundle to inform the decision making of subsequent investigations of an entire fuel channel containing a string of twelve bundles.

• The Journal of Asian Finance, Economics and Business
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• 제9권1호
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• pp.93-103
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• 2022

The main purpose of this study was to gauge the patient satisfaction index and subsequently discuss the Importance-Performance (IP) matrix analysis of the inpatient services in the context of the private hospital setting. The Malaysian Customer Satisfaction Index Model was employed as the theoretical framework for the above purposes. This study involving 242 patients in Malaysian's private healthcare sector used a Web-based survey as the main method of data collection. Partial least square structural equation modeling (PLS-SEM) was utilized for data analysis. Using Fornell et al. (1996)'s formula, the resulting patient satisfaction index was slightly lower than the "very satisfied" category, the target level required for positioning as one of the world's premier medical tourism players. The IP matrix showed that medical quality is the main competitive advantage of the private hospitals that can propel their growth in the global healthcare marketplace. The results also indicate that outcome quality, patient rights, and privacy, and service quality are the three quality domains that need to be prioritized for further improvement. On the other hand, the servicescape quality domain needs to be strategized as the unique selling proposition as the performance of the private hospitals in this regard is already extremely good.

• 한국항해항만학회지
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• 제48권2호
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• pp.78-87
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• 2024

To quantitatively assess the correlation between subsystems within a port cluster and the overall coordinated development of the port group, the current paper evaluates the coordinated development of port clusters. First, we construct an evaluation index system for the coupling and coordination of port clusters. Next, we introduce the contribution index of port subsystems, coupling degree, and coupling coordination degree functions to formulate a coupling coordination evaluation model for the port cluster. Finally, we use the Yangtze River Delta port cluster as a case study for validation, specifically using empirical data from 2012 to 2021. The findings reveal distinct phased characteristics in the coupling and coordination of port clusters in the Yangtze River Delta, marked by a notable transition from "maladjustment" to "coordination." Further, sustained high coupling values over a decade indicate a significant level of competition and cooperation among ports within the Yangtze River Delta port cluster. Over time, this competitive and collaborative dynamic has progressively evolved toward a more positive and structured direction. Lastly, it is expected that the evaluation model proposed in this paper can be extrapolated to other port clusters to gauge the extent of coordinated development, thereby facilitating horizontal comparisons and vertical analyses.

• 농촌계획
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• 제20권1호
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• pp.63-76
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• 2014

The purpose of this study is to identify effect in how urban garden is run by different operators in Korea, and consequently how it determines the level of community formation among urban garden users. Based on this analysis, the study is intended to present some points as to how to better manage urban garden. The operators are divided into three types: public, public-private partnership and private. The study interviewed each operating entity and surveyed garden users to gauge the extent to which communities are developed. After the ANOVA analysis and Scheffe post-hoc analysis, it was found that the levels of community formation among users of public and public-private partnership urban gardens were similar (so can be grouped together), whereas that of private urban garden users was higher (separated as another group). However, this study found no meaningful differences in the level of community formation among all types of urban garden in a local community. Some key suggestions are made as a result. First, as for the public and public-private partnership types of urban garden, it is necessary to foster leaders to build a community. Next, it is worth noting the potential of public-private partnership in realizing community revival through urban garden. The last suggestion is that, generally, the urban garden has only little influence on community formation in a local area so far, thus more practical consideration needs to be given to enhance the role of urban garden in a local community.