결과 내 재검색





        검색결과 34

        2023.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Fluorescent probe were used to evaluate the effects of catechin on the structural parameters (annular lipid fluidity, transbilayer lateral and rotational mobility and protein clustering) of the Porphyromonas gingivalis outer membrane (OPGs). An experimental procedure was used on the basis of selective quenching of 1,6-diphenyl-1,3,5-hexatriene (DPH) and 1,3-di(1-pyrenyl)propane (Py-3-Py) by trinitrophenyl groups and radiationless energy transfer from the tryptophans of membrane proteins to Py-3-Py and DPH. Catechin increased the bulk lateral and rotational mobility, annular lipid fluidity of OPGs lipid bilayers, and had greater fluidizing efficacy on the outer monolayer than the inner monolayer. It also caused membrane proteins to cluster. Based on these effects of catechin on OPGs, the antibacterial and antiviral actions of catechin can be partially explained.
        2022.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study investigates beginning EFL teachers’ emotional labor from the perspective of the Activity Theory. Emotional labor is defined as the process of controlling one's emotions and emotional expressions in accordance with the occupational standards for proper emotional expression. Two beginning EFL teachers at Korean junior high schools were recruited by means of a qualitative research method. Semi-structured interviews were conducted and analyzed based on Activity Theory. The findings indicate that participants’ emotional labor in relation to their students was represented as conflicts in their activity system. Additionally, the resolution of the conflicts could be possible if a teacher can join a new teacher learning community and use new instruments. The results suggest that beginning EFL teachers should be encouraged to be empowered with new instruments such as classroom management skills and teaching practices for handling mixed-level students. These new instruments are expected to prevent students’ problem behavior and ease the burden of teachers experiencing emotional labor.
        2021.06 구독 인증기관 무료, 개인회원 유료
        This study summarizes the recent cutting-edge approaches for dentin regeneration that still do not offer adequate solutions. Tertiary dentin is formed when odontoblasts are directly affected by various stimuli. Recent preclinical studies have reported that stimulation of the Wnt/β-catenin signaling pathway could facilitate the formation of reparative dentin and thereby aid in the structural and functional development of the tertiary dentin. A range of signaling pathways, including the Wnt/β-catenin pathway, is activated when dental tissues are damaged and the pulp is exposed. The application of small molecules for dentin regeneration has been suggested as a drug repositioning approach. This study reviews the role of Wnt signaling in tooth formation, particularly dentin formation and dentin regeneration. In addition, the application of the drug repositioning strategy to facilitate the development of new drugs for dentin regeneration has been discussed in this study.
        2020.12 구독 인증기관 무료, 개인회원 유료
        Several factors, including genetic and environmental insults, impede protein folding and secretion in the endoplasmic reticulum (ER). Accumulation of unfolded or mis-folded protein in the ER manifests as ER stress. To cope with this morbid condition of the ER, recent data has suggested that the intracellular event of an unfolded protein response plays a critical role in managing the secretory load and maintaining proteostasis in the ER. Tauroursodeoxycholic acid (TUDCA) is a chemical chaperone and hydrophilic bile acid that is known to inhibit apoptosis by attenuating ER stress. Numerous studies have revealed that TUDCA affects hepatic diseases, obesity, and inflammatory illnesses. Recently, molecular regulation of ER stress in tooth development, especially during the secretory stage, has been studied. Therefore, in this study, we examined the developmental role of ER stress regulation in tooth morphogenesis using in vitro organ cultivation methods with a chemical chaperone treatment, TUDCA. Altered cellular events including proliferation, apoptosis, and dentinogenesis were examined using immunostaining and terminal deoxynucleotidyl transferase dUTP nick end labeling assay. In addition, altered localization patterns of the formation of hard tissue matrices related to molecules, including amelogenin and nestin, were examined to assess their morphological changes. Based on our findings, modulating the role of the chemical chaperone TUDCA in tooth morphogenesis, especially through the modulation of cellular proliferation and apoptosis, could be applied as a supporting data for tooth regeneration for future studies.
        2020.03 구독 인증기관 무료, 개인회원 유료
        Enamel knot (EK)—a signaling center—refers to a transient morphological structure comprising epithelial tissue. EK is believed to regulate tooth development in early organogenesis without its own cellular alterations, including proliferation and differentiation. EKs show a very simple but conserved structure and share functions with teeth of recently evolved vertebrates, suggesting conserved signaling in certain organs, such as functional teeth, through the course of evolution. In this study, we examined the expression patterns of key EK-specific genes including Dusp26 , Fat4, Meis2, Sln , and Zpld1 during mice embryogenesis. Expression patterns of these genes may reveal putative differentiation mechanisms underlying tooth morphogenesis.
        2020.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigates the historical development of English education in South Korea regarding the fourth and fifth National Curriculum Period. By analyzing the newspaper articles in five major newspapers in Korea, we focused on the characteristics of English education in each period. The research questions are: 1) what are the characteristics of the fourth National Curriculum? 2) what are the characteristics of the fifth National Curriculum?, and 3) what is the implication of these previous curricula on the current English education in South Korea? During the fourth National Curriculum Period, after the successful hosting of the 1986 Asian Games and the 1988 Summer Olympic Games in Seoul, the importance of communication skills in English spread throughout the country. Accordingly, the need for early English education emerged. In the fifth curriculum, various social factors, including the liberalization of overseas travel, led positive washback effects on English education. In elementary schools, English instructions were conducted as a special activity. In secondary schools, various changes in the educational environment were involved, including the introduction of listening tests and recruitment of native English teachers, which still affects English education in 2020. This paper concludes with educational implications and future research directions.
        2020.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        물 유거(Run-off)에 따른 토양유실량을 자동정량하고자 ISCO 6712 수질환경 종합측정장치를 이용하여 토양유실량 추정장치를 고안하였고, 이 장치를 통해 실시간으로 유실되는 토양량을 추정할 수 있었다. 토양유실량 추정장치는 ISCO 6712 장치에 수위계(ISCO 730), 우량계(ISCO 674) 그리고 흙탕물을 받는 저수조 내에 층위 별로 흙탕물을 자동으로 채취할 수 있는 시설을 추가하였다. 1 × 5 m2 크기, 경사 15 %의 라이시미터(lysimeter) 내 석비레(Saprolite) 토양에 옥수수를 심어 실험한 결과 2017년 1회 강우량 161.3 ㎜의 강우사상에서는 실측 토양유실량의 85.1%, 82.6 ㎜ 강우사상에서는 101.7 %의 토양량을 추정하였다.
        2019.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 논문은 농업의 공익적 가치 확산의 일환으로 추진되고 있는 농업환경보전 프로그램의 성공적 도입을 위해 농업환경보전 실천기술 도입의 우선순위를 분석하고, 지역 환경에 적합한 맞춤형 농업환경보전 실천기술 패키지를 제시하는데 목적이 있다. 농업환경보전 실천기술은 토양·용수·대기 3개 분야, 9개의 세부분야, 30개의 실천기술로 이루어져 있다. 우선순위 분석을 위해 AHP와 BWS의 이점을 적절하게 사용하여, 3개 분야와 9개 세부분야는 AHP기법으로, 분야별 실천기술은 BWS기법으로 우선순위를 측정하여 연구의 차별성 및 완성도를 높였다. 또한, 실천기술 우선순위 평가를 위한 기준은 환경효과성과 기술적용의 용이성을 이용하였다. 우선순위 종합 평가결과, ‘토양검정 및 비료·가축분뇨 사용량 감축’ 활동이 가장 높은 우선순위를 가지는 것으로 평가되었다. 이러한 실천기술에 대한 우선순위 결과를 바탕으로 영농형태별 및 환경조건별 맞춤형 실천기술 패키지의 사례를 제시하였다.
        2019.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 논문은 우유자조금 지출의 경제적 효과를 계측한 것이다. 특히, 자조금 지출에 따른 광고효과로 백색시유에 대한 수요증가와 그에 따른 백색시유 판매수입 증가에 국한하여 그 효과를 추정하였다. 다섯 가지 형태의 백색시유 수요함수 추정을 통해 백색시유에 대한 자조금탄성치를 추정하고 이를 통해 자조금 1원당 경제적 효과를 계측하였다. 추정결과, 우유자조금 1원당 경제적 효과는 단기(1달)에서 3.8원~5.1원의 경제적 효과가 있고, 다항시차모형(PDL model)을 적용하여 장기 누적효과(1년)를 계측한 결과 자조금 1원당 8.8원~10.5원의 경제적 효과가 있는 것으로 계측되었다.
        2018.12 구독 인증기관 무료, 개인회원 유료
        본 실험은 마우스를 이용해 급성신부전에 대한 WK 추출물의 효과를 알아보고자 하였다. 실험 종료 후, 대조군은 항암제 주입 후 정상 대조군에 비해 혈중 BUN 및 creatinine 수치가 상승된 것을 확인할 수 있었고, WK-50군, WK-100군 및 WK-200군은 대조군에 비해 수치가 감소된 것을 확인할 수 있었다. 그 중 WK-200군은 정상 대조군과 유의한 수준의 혈중 BUN 및 creatinine 수치가 관찰되었다. 조직학적 결과에서 적출한 신장 장기의 형태학적 손상을 알아본 결과, 대조군에서는 현저한 신손상이 관찰되었다. 반면, WK-50군 및 WK-100군에서는 신손상이 관찰되었으나 대조군에 비하여 그 정도가 심하지 않았고, 특히 WK-200군에서는 신손상이 거의 관찰되지 않았음을 알 수 있었다. 따라서 WK 추출물은 급성신부전에 유의한 효과를 보이는 것으로 생각된다.
        2018.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study examined the characteristics of male high school English learners’ motivation and the relations between their motivation and achievement in English learning. A total of 334 Grade 10 students in a boys’ high school participated in this study by completing a questionnaire survey on second language (L2) learning motivation and taking an English achievement test. As a result of explanatory factor analysis, five factors were found as underlying constructs for male high school students’ English learning motivation: The Ought-to L2 Self, The Ideal L2 Self, The Feared L2 Self, Instrumentality, and Intrinsic Motivation. In terms of the structural relationships between the learners’ motivation and achievement in English learning, the ideal L2 self and intrinsic motivation exerted a direct impact on their motivated L2 behavior, and then English achievement mediated by the motivated L2 behavior. The other factors had an indirect influence on motivated L2 learning behavior, mediated by the ideal L2 self and intrinsic motivation. Based on the findings, we suggested motivational activities to realize the creation of the ideal L2 self among male high school English learners.
        2017.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study examined differences in South Korean students’ motivation to learn English as a foreign (EFL) from elementary to high school, and investigated the impact of private education experience on their English learning. A questionnaire was administrated to 7,957 students in elementary through high school. This crosssectional survey results revealed that EFL students’ motivation to learn English presented different levels of medians depending on their school grades and levels; it showed lowering trends from the elementary to high school levels. However, during the same period, students’ perceptions of the importance of learning English was not in a downward trend. Students with private education experience tended to have a higher level of motivation than did those without private education experience, especially with respect to instrumental, intrinsic, and integrative motivations. Socioeducational factors in South Korea, such as excessive pressure from the College Scholastic Ability Test and hakbul orientation, are discussed.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The study discussed advanced-level Korean high school EFL learners’ demotivation and remotivation strategies in English learning. Demotivation refers to specific external forces that reduce or harm motivation; remotivation is the process of recovering the reduced motivation. Although both are common in L2 learning, only a few studies address this issue. Using the survey data of 130 participants, the study identified eight demotivating factors through factor analysis. The first factor, negative attitude toward English, indicates that even high school students felt demotivated because of the sheer difficulty of studying English. Descriptive statistics revealed that a negative attitude toward the English-speaking community was not a strong demotivator, which indicated that students possessed Machiavellian motivation. Correlation and regression analysis suggested that no demotivator had a significant negative relationship with English scores; rather, the ways students perceived the demotivators were more important. Eight remotivation strategies were identified; among those, “Keep thinking about the social importance of English” was the most often mentioned one. These results suggested the need for further qualitative, systemic research on remotivators and for training programs for practicing remotivation strategies.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목 적: 기존의 콘택트렌즈 분석기에서 1매의 렌즈를 삭제하여 시스템을 간소화하고, 수차를 감소시켜 콘택트렌즈 표면의 선명한 상을 얻는 저가격 고성능의 광학계를 최적화 설계하였다. 방 법: 기존의 콘택트렌즈 분석기의 광학적 성능 분석과 최적화 설계에 사용한 파장은 프라운호퍼 C, d, F선(0.656 ㎛, 0.587 ㎛, 0.486 ㎛)이며 기준파장은 d선으로 하였다. Full field는 object height를 5 mm로 설정하였다. 참고모델의 광학적 성능 분석과 분석기의 최적화 설계에는 Zemax 14.2 설계 프로그램을 사용하였다. 결 과: 최적화 설계한 콘택트렌즈 분석기는 기존의 콘택트렌즈 분석기보다 Spot diagram RMS radius는 42.51% 성능이 향상되었다. 상질에 영향을 주는 구면수차는 96.96%, 비점수차는 68.39%, 종 방향 색수차는 39.29%, 횡 방향 색수차는 95.97% 향상되었고, 상면만곡과 왜곡수차는 각각 82.09%와 66.05%로 수차 성능이 향상되었다. 결 론: 기존의 콘택트렌즈 분석기보다 적은 수차와 적은 렌즈 매수를 갖는 새로운 광학계를 설계하였다. 설계한 콘택트렌즈 분석기는 저가격, 고성능의 성능 최적화가 이루어졌다고 볼 수 있다.
        2014.12 구독 인증기관 무료, 개인회원 유료
        2013.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This theoretical position paper highlights how second language (L2) learning demotivation or decrease in motivation can be reconceptualized within the framework of Vygotskian Activity Theory (AT). Previous demotivation studies primarily focused on determining the demotivating factors. There has not been sufficient academic attention to the dynamic interaction between L2 learners and their potential factors for demotivation. In this paper, we attempted to apply AT in order to explain this intricate demotivation process, particularly focusing on L2learners’ subjective perceptions of their learning environment. From the perspective of AT, L2 learners’ learning-related activities are seen as activities composed of subject, object, mediational tool, community, rule, and division of labor. Describing a learner’s L2 learning experience in Lantolf and Genung’s (2002) study, we argue that the tensions emerging between the elements in the activity system result in demotivation. Future directions and the issue of commensurability of AT with other theories are discussed.
        2013.09 구독 인증기관 무료, 개인회원 유료
        This study evaluated the efficacy and safety of medi- cal shampoo containing terbinafine hydrochloride and chlorhexidine gluconate in dogs with dermatophytos is complicated with bacterial infection. Although several stud- ies in dogs and cats with fungal dermatitis have found that oral administration of terbinafine is effective for controlling clinical signs, the topical form of terbinafine has rarely been studied in dogs and cats. Therefore, this study evaluated the efficacy of medical shampoo containing terbinafine hy- drochloride and chlorhexidine gluconate in dogs with der- matophytos is complicated with bacterial infection. Eight dogs infected with Microsporum spp. complicated with bacterial infection were enrolled in this study. These dogs were further blindly divided into Group 1 (no treatment, fourdogs) and group 2 (treated with medical shampoo with terbinafine/chlorhexidine, four dogs). Clinical improvement was evaluated using bacterial and fungal cultural evaluation combined with clinical evaluation. This study found that the medical shampoo has sufficient efficacy to treat varying degrees of dermatophytosis complicated with bacterial in- fection in dogs, although the speed of improvement differed according to the degree and type of infection. Our study also found that combined therapy using antifungal and antibac- terial agents can improve clinical signs more effectively and rapidly, suggesting that concurrent bacterial infection plays a significant role in the development of dermatitis.
        2012.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Due to the increase in international trade, mass transportation, and information technology, the role of English as a global language has changed, and conventional EFL/ESL motivation needs paradigmatic reconstruction. This study compares Dörnyei’s (2009) recent proposal of a second language (L2) motivat-ional self-system with Gardner’s (1985) socio-educational model by investigating 2,832 Korean students’ English learning motivation from Grades 3 through 12 in 14 different schools. The cross-grade survey results indicated that Korean EFL learners’ motivational intensity showed a curvilinear pattern, which means their motivation consistently decreased until Grade 9 but increased from Grades 10 to 12. A series of regression analyses showed that Dörnyei’s L2 motivational self-system was a better predictor than Gardner’s socio-educational model in terms of the explanatory power for students’ English proficiency; students’ ideal L2 and ought-to L2 selves explained better than integrativeness and two types of instrumentality (i.e., promotion- and prevention-based). This confirms the findings of recent literature conducted in different nations. Also, the study provides empirical evidence that the ought-to L2 self, which is an external, social form of L2 motivation, functions only at the cognitive level, whereas the ideal L2 self, a more internalized form, taps into both the cognitive and affective levels.
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