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        검색결과 519

        401.
        2012.09 KCI 등재 서비스 종료(열람 제한)
        남극 지의류인 Ramalina terebrata에서 분리 정제된 라말린(γ-glutamyl-N'-(2-hydroxyphenyl)hydrazide)은 이전 연구에서 강력한 항산화능을 확인하였다. 본 연구에서는 라말린의 추가적인 효능을 확인하기 위하여, 비암세포 세포주인 멜란에이 세포를 이용하여 라말린의 멜라닌 합성에 대한 효과를 확인하였다. 라말린은 세포 독성이 없는 농도에서, 멜란에이 세포에서 멜라닌 합성을 농도 의존적으로 감소시켰으며, 이러한 효과는 널리 사용되고 있는 미백제인 알부틴보다 우수하였다. 라말린은 무세포 타이로시네이즈의 활성을 직접 저해했을 뿐만 아니라, 세포 내의 타이로시네이즈의 활성도 저해하는 효과를 보였다. 라말린의 이러한 멜라닌 합성 저해의 기전 연구를 위하여, 멜라닌 합성에 중요한 단백질인 타이로시네이즈, TRP-1, TRP-2의 mRNA와 단백질 발현을 조사한 결과, mRNA양에는 영향을 주지 않고,단백질의 발현은 감소되는 것으로 나타났다. 또한, 0.2 % 라말린을 포함한 제형을 사람피부에 도포하였을 때, 3주 후에 피부 밝기가 개선됨을 확인하였다. 이상의 결과를 통해서, 라말린은 타이로시네이즈의 직접적인 저해뿐만 아니라 멜라닌 합성과 관련된 단백질의 발현을 저해함으로써 미백효과를 나타낸다고 할 수 있으며, 이러한 효과를 인체시험을 통해 확인하였다. 따라서, 라말린은 멜라닌 합성을 저해하는 미백 소재로 활용될 수 있을 것으로 판단된다.
        402.
        2012.09 KCI 등재 서비스 종료(열람 제한)
        A role of students' affective factors in assessing their non-native teachers of English. Studies in Modern Grammar This study investigated the relationship between non-native English as a Foreign Language (EFL) students’ perceptions of their non-native teachers and their own affective variables. A total of 189 subjects in this study responded to a Likert-type scale instrument that measured their self-directed learning behavior, anxiety, class participation, their perceived teachers’ teaching ability, closeness with their teachers, and anxiety aroused in the presence of their teachers. Following principal factor analyses to check the construct validity of each construct, canonical correlation analysis was performed to understand to what extent subjects’ perceptions of their non-native teachers of English can be related to their affective states are related. The results indicated that the two sets were moderately correlated in two functions with canonical coefficients 0.52 and 0.37, suggesting that perceptions of non-native teachers may be related to learners’ affective states. Further analyses showed that students who reported high on self-regulatory learning behavior and classroom participation were likely to feel that their teacher was close to them, were still likely to feel anxious, and tended to feel positive about their teacher’s teaching ability. In addition, this study found that students with low foreign language anxiety were likely to manifest low belief in their teacher’s teaching ability, were likely to feel distant from their teacher, and likely to have the fear of negative evaluation.
        403.
        2012.07 서비스 종료(열람 제한)
        In plants, the Dof (DNA binding with One Finger) proteins are plant-specific transcription factors with a particular class of zinc-finger DNA-binding domain. The Dof genes have been predicted 30 different Dof genes in the rice Oryza sativa genome by phylogenetic analysis. The mostly Dof proteins contain a conserved region of 50 amino acids with a C2-C2 zinc finger motifs that binds a cis-regulatory element sequence 5’-T/AAAAG-3’. We found that a member of the DOF transcription factor family, Dof1 gene of rice, was expressed to wound from Ds insertion mutant population. Sequencing of the flanking regions of the transposon insertion site indicated that the gene-trap had been inserted near the front of the second exon of OsDof1 gene in chromosome 7. Genomic southern analysis revealed that mutant line contained a single copy of Ds gene trap. The Ds tagged rice mutant line, OsDof1::Ds, wound-inducible GUS expression was identified. To analyze the cis-acting elements, we constructed fusion genes with the OsDof1 promoter fused to the β-glucuronidase (GUS) reporter gene and transformed Arabidopsis and rice plants with these constructs. Wound-induced GUS expression was observed in the leaves of transgenic OsDof1::GUS rice and Arabidospsis plants. These results showed that, OsDof1 protein might be involved in stress responses and growth regulation in plant, might plays a role as a transcription regulator in stress response signal transduction pathways of plant.
        404.
        2012.07 서비스 종료(열람 제한)
        Maesopsis eminii, known as ‘umbrella tree’ in English, occurs naturally between 6oS and 8oN in tropical Africa. It is a species of moist forests and an early succession species, adapt at colonizing grasslands and disturbed areas in the high forest. It is widely distributed in forest re-growth and remarkably long lived for a pioneer species, attaining over 150 years. M. eminii was introduced into Java, Indonesia in the 1920s and has been widely cultivated in Java, Sumatra and Kalimantan for timber plantations due to its timber value, fast growing and leave usage for fodder. Annual wood production potential is 30 m3/ha in Africa and 40 m3/ha in Indonesia. The final rotations for timber production are 20-30 years in Africa and 10-20 years in Indonesia, and rotations for fuel wood, poles and pulp production are about 8 years. Genetic resources (plus trees) of M. eminii growing in several populations from west Java were collected, and a progeny test of the 100 open-pollinated families was established in west Java, Indonesia. Early results from a field test of M. eminii are reported from the progeny test trial. Seedling height and diameter at root collar (DRC) were measured at 0, 10 and 15 months of ages. Age 0 means the measurement just before the planting. The averages of seedling height and DRC at age 15 months were 134.4 cm and 1.86 cm. Family survival rates were, on average, 65.6% and 62.8% at age 10 and 15 months, respectively. Family genetic variance and replication variance at age 15 months were higher than those at age 10 months. Seedling height was positively correlated with DRC growth and statistically significant at the same ages. The coefficients of genetic variation for seedling height and DRC were ranged from 0.01 to 12.69 and from 1.97 to 13.70. Heritability estimates obtained were 0.44, 0.04, 0.01, and 0.31, 0.01 and 0.02 for seedling height and DRC at age 0, 10 and 15 months, respectively. Family averages of the 10 best and the 10 poorest families for each trait indicated that there were large differences of seedling height and DRC growth among families and between ages. Genetic gain for DRC was expected to be substantial and higher than that for seedling height growth at age 15 months. Those results suggested that growth improvement through the superior family selection of M. eminii could be possible.
        405.
        2012.06 KCI 등재 서비스 종료(열람 제한)
        Northern corn leaf blight caused by Exserohilum turcicum Pass is considered the most important disease infecting corn (Zea mays L.) in the Peoples' Republic of Korea (North Korea). It contributes to the food shortage in North Korea. The objectives of the current research were to study resistance expression and responses of corn crosses made between ten hybrids from North Korea and inbreeding lines (S3-4 stage) from the Republic of Korea (South Korea). The experiments were conducted in six trials with a total of 184 crosses including two commercial hybrids in each trial. The trials were conducted at two locations in North Korea (Mirim and Eunsan) and one location in South Korea (Gunwi) under natural infestation of E. turcicum. Host plant responses were rated on a scale of 1 (highly tolerant) to 9 (highly susceptible). A total of 111 crosses (62.4%) showed significant tolerant or susceptible response variations among three locations; 42 crosses (22.8%) at two locations and 69 crosses (39.0%) at one location, respectively. At least 8 crosses of high level of tolerance and 12 crosses of high level of susceptibility showed significantly different biotic responses (P = 0.05). The results of the current study and historical reviews of E. turcicum epidemics in both North and South Korea suggest that breeding of tolerance with quantitatively inherited genes should be carried out for a sustainable corn production in North Korea.
        406.
        2012.05 서비스 종료(열람 제한)
        The difference in phase and amplitude of ground motions recorded in different locations is generally known as spatial variation of seismic ground motions. This study focuses on the effects of spatial variation of earthquake ground motion on responses of adjacent buildings. The adjacent frame buildings are modeled considering soil-structure interaction (SSI) so that all the buildings can have interaction with each other under non-uniform ground motions. Based on Fast Fourier Transformation, spatially correlated non-uniform ground motions are generated compatible with known spectrum density function at different locations. Numerical analyses are carried out and the results are presented in terms of related parameters affecting the structural response using three different types of soil site classes. The results show that the effects of ground motion spatial variation are different for different site classes. The effect is more significant on rock site rather than clay site.