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        검색결과 32

        2.
        2020.12 구독 인증기관 무료, 개인회원 유료
        Excessive intake of sodium caused by high salt diet promotes the expression of inflammatory cytokines and differentiation of helper T cells resulting in inflammatory responses. High-glucose diet also contributes to the pathogenesis of periodontitis by inducing changes in the oral microbiome and reducing salivation. However, the effect of a high-salt and glucose diet (HSGD) on the prognosis of periodontitis remains unclear. In this study, a rat model of experimental periodontitis was established by periodic insertion of absorbable sutures containing Porphyromonas gingivalis and Fusobacterium nucleatum strains into the right gingival sulcus to analyze the effect of HSGD on the incidence and progression of periodontitis. The alveolar bone heights (ABH) was measured with microcomputed tomography imaging of the HSGD- and general diet (GD)-treated groups. The right ABH was significantly decreased compared to the left in both groups at 4 weeks after induction of inflammation; however, no significant difference was noted between the groups. Notably, the ABH in the HSGD-treated group was significantly decreased at 8 weeks after induction of inflammation, whereas in the GD-treated group, an increase in the ABH was observed; a significant difference of the ABH was noted between the two groups (p < 0.05). At 12 weeks, recovery of the alveolar bone was observed in both groups, with no significant differences in ABH between the two groups. These findings indicate that the intake of excessive sodium attenuates the recovery rate of the alveolar bone even after the local infectant is removed. In addition, this study demonstrates the use of HSGD in establishing a new animal model of periodontitis.
        4,000원
        4.
        2018.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        고준위방사성폐기물 심지층 처분 대상 암종으로 고려되는 화강암에서 방사성핵종의 장기 거동특성을 이해하기 위한 연구의 일환으로 KURT (KAERI Underground Research Tunnel) 화강암에 존재하는 우라늄의 용출특성에 대한 연구를 수행하였다. 반응 시작 후부터 10일 동안의 반응기간 중 다른 반응용액에 비해 CO3 2- 농도가 높은 UD-CO3 및 UD-Bg 반응용액에서 우라늄의 용출량이 다소 급격하게 증가하였다. 또한 Na 또는 Ca가 다량 함유된 반응용액에서 반응 60일 이후 우라늄 용출량이 다소 급격히 증가하였다. 각 반응용액에 의한 반응 270일까지의 우라늄의 용출량은 UD-CO3 (44.61 μg·L-1), UD-Bg (41.01 μg·L-1), UD-Na (26.87 μg·L-1), UD-Ca (20.26 μg·L-1), UD-CaSi (17.03 μg·L-1), UD-Si (10.47 μg·L-1)으로 지속적으 로 증가 하였으나, 반응 270일 이후 우라늄 용출량은 점차 감소하는 경향을 나타낸다. 이는 화강암 시료 내에 존재하는 우라늄이 반응용액과 상호반응에 의해 최대 용출될 수 있는 한계에 도달하였기 때문으로 판단된다. 우라늄 용출은 혼합된 반응 용액 내의 CO3 2- 존재와 수질의 지화학적 유형에 따라 우라늄의 용출 농도 및 용출 최대치가 나타나는 시점이 다르게 확인되 었다. 이는 시료와 반응용액의 상호반응 과정에서 용존이온의 영향에 의해 화강암시료와 반응용액 사이에 반응속도의 차이가 발생하는 것으로 판단된다.
        4,000원
        8.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Synovial cysts are found mainly in periarticular areas of the wrist, ankle, and knee, but also rarely in the temporomandibular joint (TMJ). Only 1 case of bilateral synovial cysts in the region of the TMJ has been reported. This case report described bilateral cysts in the TMJ in a 54-year-old Korean woman. T2-weighted magnetic resonance imaging (MRI) revealed bilateral oval cystic lesions lateral to the condylar capsule, whereas computed tomography (CT) apparently did not show the right hand side lesion. The cyst on the left side was surgically excised, and fine needle aspiration was performed on the right hand cyst. After 24 months, the long term follow-up showed no sign of recurrence.
        3,000원
        10.
        2016.10 구독 인증기관·개인회원 무료
        The habitat of the cockroach varies by species. The German cockroach (Blattella germanica) lives in human dwellings, while the Japanese field roach (Blattella nipponica) lives in a mountainous region. Based on phylogenetic analysis of mtCO I, the two species are closely related to each other and B. germanica is divergent from wild species such as B. nipponica. Their habitats and walking speed differ even though the two species have similar morphology. We hypothesized that habitats might influence walking speed via changes to appendage morphology and enzyme-based physiological differences. We found that phenotype such as appendage length and esterase isozyme expression were clearly different between the two species. These differences might be responsible for the observed difference in walking speed.
        11.
        2012.06 구독 인증기관 무료, 개인회원 유료
        We investigated the pulpal response to direct pulp capping in rat molar teeth using mineral trioxide aggregate (MTA) and calcium hydroxide (CH). A palatal cavity was prepared in rat maxillary molar teeth. Either MTA or CH was placed on the exposed pulp and all cavities were restored with composite. Rats were sacrificed for histological evaluation after 12 hours and at 2, 7, 14 and 21 days. In both the MTA and CH groups, reparative dentin formation was clearly observed on histology after 14 days. The MTA-capped pulps were found to be mostly free from inflammation, and hard tissue of a tubular consistent barrier was observed. In contrast, in CH-capped teeth, excessive formation of re¬parative dentin toward residual pulp was evident. The pulpal cell response beneath the reparative dentin layer was examined by immunofluorescence using antibodies against DSP. After 2 days, a few DSP immunopositive cells, most of which showed a cuboidal shape, appeared beneath the predentin layer. At 7 days, DSP-immunopositive cells with columnar odontoblast-like cells were seen beneath the newly formed hard tissues. At 14 and 21 days, DSP was more abundant in the vicinity of the odontoblastic process along the dentinal tubules than in the mineralized reparative dentin. The CH group showed strong expression patterns in terms of DSP immunoreactivity. Our results thus indicate that MTA may be a more effective pulp capping material as it induces the differentiation of odontoblast-like cells and the formation of reparative dentin without the loss of residual pulp functions.
        4,000원
        12.
        2005.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        중저준위 방사성폐기물 천층처분시설의 처분덮개설계 및 성능평가를 위해 국내 역사시대 고분연구를 수행하였다. 처분덮개 성능과 관련된 국내외 연구현황을 조사하고 삼국시대 고분을 중심으로 봉분의 층상특성을 정리하였다. 국내 고분에 대한 봉토의 시료채취와 시료에 대한 수리전도도 측정 및 분석을 실시하였다. 고분에 대한 자연유사 연구에서 발굴조사보고서 상에 제시된 봉토의 유사판축기법의 적용, 모세관 방벽현상과 배수로를 이용한 봉분 내 습도조절 여부를 천층처분 시설설계에 활용할 수 있을 것으로 판단된다. 향후 국내 고분발굴현장이 있을 때 현장을 방문하여 필요한 자료수집과 더불어 원자력분야의 관심사와 필요사항에 대하여 국내 고고학계와의 정보교환이 이루어져야 할 것으로 판단된다.
        4,500원
        13.
        2000.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was carried out to determine a fertilization rate for productivity and nutritive value improvement of silage corn, using two kinds of composts, and to examine the potential possibility of utilization as an organic fertilizer. The experiment was
        4,000원
        14.
        2020.08 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The study investigates the effects of online instructional facilitator’s qualities on student performance of online class activities. The study explores the roles of instructional facilitators who may influence student performance of online class activities and their academic achievement. The study employs a set of aggregated data from 1,362 subjects and 10 facilitators who participated in multiple online classes. The results of independent samples t-test reveal that the student performance in online classes has no association with facilitators’ educational background or academic degree, as well as demographic characteristics, student evaluation records and instructional achievement. The results of multiple regression analysis show that the facilitator engagement has a positive relation to the enhancement of student interaction, reading discussion messages, and the quality of discussion messages in online discussions. The results of correlation analysis show that the facilitator engagement has a positive impact on both increasing the number of reading discussion messages and enhancing the quality of discussion messages. The facilitator engagement increases the quantity of reading discussion postings and enhances the quality of discussion messages, which would be a substantial contribution to student performance by facilitators. The findings suggest that student performance and academic achievement in online classes are not independent of facilitator engagement.
        15.
        2020.08 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The paper examines the impact of proctoring environments on student performance in two different exam proctoring environments: online versus offline proctored exams. This study employs a set of aggregated data from 1,762 students over the eight-year period from 2009 to 2016 in a university. Although there were nine courses offered, they could have been counted more than once as students may appear several times to take exams for different courses. This study employs independent samples t-test and regression analysis to compare the means of two independent groups and to test the hypothesis. The results of the independent samples t-test and the regression analysis indicate that there is no difference in the mean scores of exams and, therefore, the findings suggest that the exam proctoring environment is unlikely related to student performance even when students take their exams either in online proctoring or offline proctoring environments. This study concludes that the proctoring environment unlikely results in a statistically significant difference of exam scores and, thus, the exam proctoring environment does not appear to cause any change in student performance. The findings suggest that the exam proctoring environments does not appear to impact on student academic achievements and assessments.
        16.
        2020.08 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The study examines lagged economic effects of research and development (R&D) investment on the market value of manufacturing firms listed on the Shanghai Stock Exchange or the Shenzhen Stock Exchange in China. This study applies panel data analysis methods to address the following issues: 1) There might be an adjustment lag in the impact of R&D investment on corporate market value, and 2) Unobserved firm effects must be taken into account. The balanced panel data includes a total of 1,462 observations with 34 cross-sections of manufacturing firms listed on Chinese stock markets and with 27 time-specific quarterly periods from 2007 to 2017. The results indicate that the R&D investment of Chinese manufacturing firms tends to yield favorable market value of the firm with some adjustments to time. The results show that R&D investment exhibits a strong positive impact on their market value of manufacturing firms in Chinese stock markets. Moreover, R&D investment has a positive time-lag effect on the market value of the firm. Interestingly, the R&D investment of Chinese manufacturing firms generate a relatively constant positive effect on their market value, supporting the notion that the corresponding returns of R&D investment for such firms yield lagged but added market values.
        17.
        2020.07 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The paper seeks to explore the role of green finance in achieving sustainable development goals through the case of China, and address some issues of sustainable finance and environmental, social and governance concerns of green finance by introducing the episodes of green finance in China. This paper aims to provide some viewpoints about the following questions: 1) What are the latest trends in green finance? 2) What are the main challenges to the development of green finance? 3) What are policy recommendations for the development of green finance? 4) What are the roles of both the public and private sectors in promoting green finance? This paper identifies the mainstream to sustainable bonds, diversification of green finance, transition of corporates’ business models, transparency and disclosure, and harmonizing taxonomy and measurement of green finance for the emerging trends of green finance. As the results, this paper recommends some policy measures for the private sector such as greening the banking system, greening the bond market, and greening institutional investors. This paper also suggests some policy initiatives for the public sector such as developing policies and capacity, promoting market transparency and governance, and promoting private-public partnership for diversifying resources of green finance.
        18.
        2020.07 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The paper aims to facilitate a discussion around how big data technologies and data from citizens can be used to help public administration, society, and policy-making to improve community’s lives. This paper discusses opportunities and challenges of big data strategies for government, society, and policy-making. It employs the presentation of numerous practical examples from different parts of the world, where public-service delivery has seen transformation and where initiatives have been taken forward that have revolutionized the way governments at different levels engage with the citizens, and how governments and civil society have adopted evidence-driven policymaking through innovative and efficient use of big data analytics. The examples include the governments of the United States, China, the United Kingdom, and India, and different levels of government agencies in the public services of fraud detection, financial market analysis, healthcare and public health, government oversight, education, crime fighting, environmental protection, energy exploration, agriculture, weather forecasting, and ecosystem management. The examples also include smart cities in Korea, China, Japan, India, Canada, Singapore, the United Kingdom, and the European Union. This paper makes some recommendations about how big data strategies transform the government and public services to become more citizen-centric, responsive, accountable and transparent.
        19.
        2020.07 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The study examines the impact of corporate social responsibility (CSR) activity on the firm market value, in particular, market capitalization of tour operators listed on Chinese stock markets. This study employs panel data analysis methods to examine endogeneity concerns in observational data. The balanced panel data includes a total of 1,296 observations with 27 cross-sections of tour operators listed on Chinese stock markets and with 48 time-specific periods from March 2006 to December 2017. The results indicate that CSR activity has a negative impact on the market value of the firm for the concurrent period, but from one-period time lag and afterwards CSR activity has a strong positive impact on the market value and sustains its positive impact on the market value even for a two-period time lag. The findings suggest that the economic effect of CSR activity on the firm market value tends to take some degree of lagged effects to be fully showcased in the market capitalization of tour operators and travel companies listed on Chinese stock markets. The findings suggest that, though CSR activity may carry some financial risk for an immediate short-term, tour operators must put a lot of time and effort into making CSR actions effective.
        20.
        2019.02 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The paper aims to investigate the relationship between firm size and organizational actions on adopting social media for corporate reputation management. The sample group of 198 companies is selected with a simple random sample method from the New York Stock Exchange (NYSE) listings: Sixty nine companies were from the Fortune 500 listings, seventy one companies from the NYSE midsize capitalization and fifty eight companies from the NYSE small capitalization listings. This study employs cross tabulations and Chi-square analysis, and the Kruskal-Wallis that enables the comparison of three samples that are independent. The results of the study show that (1) large firms have more social media ownership than small firms, (2) large firms respond to social media posts at a greater frequency and quickly than small firms, and (3) firm size is less likely associated with response styles to social media for online reputation management. The results show that reply time and response styles of organizations to social media customers in the 2015 survey has no significant change compared to that of 2011. There appears to be a pervasive lack strategic framework as most firms in the study were found not to be adequately monitoring or leveraging social media communication for their reputation management.
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