• Bulletin of the Korean Chemical Society
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• 제11권6호
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• pp.521-527
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• 1990

The binding characteristics and analytical applications of anilinium ion complexes with 18-crown-6 were studied by polarography and NMR. First, the electrochemical reduction of the 10 species of mono and dimethylsubstituted anilinium ion complexes with 18-crown-6 as host in methanol are examined. The addition of 18-crown-6 to anilinium guest solution the polarographic waves remain well defined but shifted toward more negative potentials, indicating the complex formation. The values of formation constants, log Κ for 10 species of methylsubstituted anilinium ion complexes with 18-crown-6 varies from 2.7 to 4.8 in methanol at $25^{\circ}C$. The stability order of complexes for 18-crown-6 is anilinilum > 4-methyl > 3,4-dimethyl > 3-methyl > 3,5-dimethyl > 2,4-dimethyl > 2,5-dimethyl > 2,3-dimethyl > 2-methyl > 2,6-dimethylanilinium ion. The steric hindrance shows significant effect. Second, Proton NMR was used to elucidate their interaction characteristics. From the results of so called NMR titration techniques, the behaviors of binding sites on complexation, and the stoichiometry and stability order of complex were obtained. And the later results show the satisfactory agreement with the quantitative values obtained by polarography. Finally, the individual determinations of anilinium ion mixtures were also accomplished by addition of 18-crown-6. In some mixtures of methyl or dimethylanilinium ions the reduction peaks of differential pulse method appeared into one unresolved wave attributed to the small difference of half-wave potential, ${\Delta}E_{1/2}$. In the presence of 18-crown-6, the polarographic waves were resolved into individual maxima because of the shift toward more negative direction by the difference of selectivity of anilinium ions with 18-crown-6. It may be concluded that quantitative analysis of methylanilinium ion mixture make possible because the half-wave potential shift by the selectivity difference due to the steric hindrance between methyl group and 18-crown-6 on complexation.

• 한국임상약학회지
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• 제20권1호
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• pp.25-29
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• 2010

The purpose of this study was to investigate the effect of atorvastatin on the pharmacokinetics of nifedipine (6 mg/kg) after oral administration of nifedipine with or without atorvastatin (0.5 and 2.0 mg/kg) in rats, and also was to evaluate to the effect of atorvastatin on the CYP3A4 activity. The 50% inhibiting concentration ($IC_{50}$) values of atorvastatin on CYP3A4 activity is 46.1 ${\mu}M$. Atorvastatin inhibited CYP3A4 enzyme activity in a concentration-dependent manner. Coadministration of atorvastatin increased significantly (p<0.05, 2.0 mg/kg) the plasma concentration-time curve (AUC) and the peak concentration ($C_{max}$) of nifedipine compared to the control group. The relative bioavailability (RB%) of nifedipine was increased from 1.15- to 1.37-fold. Coadministration of atorvastatin did not significantly change the terminal half-life ($T_{1/2}$) and the time to reach the peak concentration ($T_{max}$) of nifedipine. Based on these results, we can make a conclusion that the significant changes of these pharmacokinetic parameters might be due to atorvastatin, which possesses the potency to inhibit the metabolizing enzyme (CYP3A4) in the liver and intestinal mucosa, and also inhibit the P-glycoprotein (P-gp) efflux pump in the intestinal mucosa. It might be suggested that atorvastatin altered disposition of nifedipine by inhibition of both the first-pass metabolism and P-glycoprotein efflux pump in the small intestine of rats. In conclusion, the presence of atorvastatin significantly enhanced the oral bioavailability of nifedipine, suggesting that concurrent use of atorvastatin with nifedipine should require close monitoring for potential drug interation.

• 교육시설 논문지
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• 제24권6호
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• pp.37-44
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• 2017

This study is about user satisfaction of the Junior College Library based on its characteristics of space composition. For this, we studied characteristics of space composition targeting the libraries in colleges in Seoul and Gyeonggi-do. First, in case of study of characteristics of space composition for books and library data, student satisfaction for traditional and normal library areas was high. It means that the service based on library areas should start from normal library areas as well as there is a change about space as the type of data in libraries change to electric data and multimedia. Second, If we look at the space for a reader and a user, satisfaction for a normal reading room was high. we can also see that satisfaction for a computer room and a multimedia reading room was not higher but still high. Also, the reason why satisfaction for a multimedia reading room that provides various activities was high was that the complex of a library space is needed to provide users with various activities. Third, in case of space for programme function and meeting, satisfaction for the room of video information and the group study room was high. we can see that user satisfaction for the space got high basically when a user is satisfied with the proper information technology based on interaction Fourth, as a result of variance analysis of 3 spaces of Junior College Library and the services, the size of the space of service does not influence user satisfaction directly. Even the space is small, if it decorates variously like with a lighting for a user, a window seat to meet the nature of users and has specific factors such as space reservation using internet, user satisfaction is high. If we summarise the result of this study, to make user satisfaction for speace in a Junior College Library higher, not just we need to try to make it extend as a educational, a cultural place but we also need to accept the student's requirement that the space also needs to be extend as a complex cultural space.

• 한국수학교육학회지시리즈A:수학교육
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• 제58권4호
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• pp.519-530
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• 2019

선행연구에 의하면 수학 학습활동에서 인지적, 정의적 요소들 사이의 상호작용에 기반하는 메타정의는 메타인지와 유사한 방식으로 학습자의 수학적 능력과 긴밀한 역학적 관련성을 유지한다. 본 연구에서는 이러한 특성을 현상학적으로 파악하기 위하여 초등학교 5학년 수학 영재아의 소집단 문제해결 사례를 메타정의적 관점에서 분석하였다. 그 결과 수학 영재아의 인지적, 정의적 특성이 메타정의적 활동을 통해 문제해결 활동에 나타나고 있음을 알 수 있으며, 특히 문제해결자의 정의적 역량은 정서나 태도 형태의 메타정의로 문제해결 활동에 작용함을 알 수 있었다.

• 교육녹색환경연구
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• 제6권1호
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• pp.1-24
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• 2007

Public library is established on impartial accessibility of any distinction as their sex, age, financial status, etc. The function of public library is not only to accumulate materials and offer information but also minimize gulf between the rich and the poor by knowledge possession, which is realized by important means to intercept exclusive possession and power in knowledge pose-industrial society. As it is judged that most public library is established to individual building with thousands of cost, it is judged of obstacles to Increase library buildings. The purpose of this study is try to find the way to Increase In number of public library In Seoul by interaction local education-cultural facilities. The result from this study, the user rate of public library is influenced by number of buildings and accessibility of traffic and public library can improve efficiency by substantial operation by basic function for all age group. The target population of Seoul public library sizes by decuple of advanced countries because of difficulty of accessibility, so it needs to make it small scale and also can offer self-regulation learning, materials and life-long learning programs because generally public library's utilization purpose is different by age. As school in Seoul amounts to 25 times of public library by about 1,200 buildings and can function of lifelong education center with a school library, cultural center and other composition buildings, so school facilities may use as a public library for local residents.

• BMB Reports
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• 제35권1호
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• pp.116-126
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• 2002

Nitric oxide (NO), synthesized from L-arginine by NO synthases, is a small, lipophilic, diffusible, highly reactive molecule with dichotomous regulatory roles in many biological events under physiological and pathological conditions. NO can promote apoptosis (pro-apoptosis) in some cells, whereas it inhibits apoptosis (anti-apoptosis) in other cells. This complexity is a consequence of the rate of NO production and the interaction with biological molecules such as metal ion, thiol, protein tyrosine, and reactive oxygen species. Long-lasting overproduction of NO acts as a pro-apoptotic modulator, activating caspase family proteases through the release of mitochondrial cytochrome c into cytosol, up-regulation of the p53 expression, and alterations in the expression of apoptosis-associated proteins, including the Bcl-2 family. However, low or physiological concentrations of NO prevent cells from apoptosis that is induced by the trophic factor withdrawal, Fas, $TNF{\alpha}$/ActD, and LPS. The anti-apoptotic mechanism is understood on the basis of gene transcription of protective proteins. These include: heat shock protein, hemeoxygenase, or cyclooxygenase-2 and direct inhibition of the apoptotic executive effectors caspase family protease by S-nitrosylation of the cysteine thiol group in their catalytic site in a cell specific way. Our current understanding of the mechanisms by which NO exerts both pro- and anti-apototic action is discussed in this review article.

• Bulletin of the Korean Chemical Society
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• 제27권4호
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• pp.495-502
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• 2006

Intramolecular energy flow and C-$H_{methyl}$ and C-$H_{ring}$ bond dissociations in vibrationally excited toluene in the collision with HF have been studied by use of classical trajectory procedures. The energy lost by the vibrationally excited toluene upon collision is not large and it increases slowly with increasing total vibrational energy content between 20,000 and 45,000 $cm ^{-1}$. Above the energy content of 45,000 $cm ^{-1}$, however, energy loss decreases. Furthermore, in the highly excited toluene, toluene gains energy from incident HF. The temperature dependence of energy loss is negligible between 200 and 400 K. Energy transfer to or from the excited methyl C-H bond occurs in strong collisions with HF transferring relatively large amount of its translational energy (>> $k_BT$) in a single step, whereas energy transfer to the ring C-H bond occurs in a series of small steps. When the total energy content $E_T$ of toluene is sufficiently high, either C-H bond can dissociate. The C-$H_{methyl}$ dissociation probability is higher than the C-$H_{ring}$ dissociation probability. The dissociation of the ring C-H bond is not the result of the intermolecular energy flow from the direct collision between the ring C-H and HF but the intramolecular flow of energy from the methyl group to the ring C-H stretch. The C-$H_{ring}$${\cdot}{\cdot}{\cdot}$HF interaction is not important in transferring energy and in turn bond dissociation.

• Bulletin of the Korean Chemical Society
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• 제32권11호
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• pp.3947-3951
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• 2011

The nucleophilic substitution reactions of Y-aryl ethyl chlorothiophosphates with X-pyridines are studied kinetically in acetonitrile at $55.0^{\circ}C$. The Hammett and Bronsted plots for substituent X variations in the nucleophiles exhibit biphasic concave upwards with a break point at X = 3-Me. The substituents of X = 4-CN and 4-Ac show great positive deviations from both the Hammett and Bronsted plots. The Hammett plots for substituent Y variations in the substrates exhibit biphasic concave upwards with a minimum point at Y = H. The obtained values of the cross-interaction constants (${\rho}_{XY}$) are all in spite of the biphasic free energy correlations for both substituent X and Y variations, since the ${\rho}_X$values with both the strongly and weakly basic pyridines are almost constant. A stepwise mechanism with a rate-limiting leaving group departure from the intermediate is proposed where the distance between X and Y does not vary from the intermediate to the second transition state. A frontside attack is proposed with the strongly basic pyridines based on the considerably great magnitudes of ${\rho}_X$ and ${\beta}_X$ values and a backside attack is proposed with the weakly basic pyridines based on the relatively small magnitudes of ${\rho}_X$ and ${\beta}_X$. The positive deviations of the two strong ${\pi}$-acceptor parasubstituents, X = 4-Ac and 4-CN, from both the Hammett and Bronsted plots are rationalized by the great extents of bond formation and breaking.

• 한국콘텐츠학회논문지
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• 제11권12호
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• pp.986-997
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• 2011

본 연구는 학습을 위한 멀티미디어 활용에 대한 설계 원리 중 멀티미디어 원리와 개인차 원리가 스마트패드 기반 콘텐츠에서도 적용되는지 살펴보았다. 이를 위해 텍스트 기반 콘텐츠와 멀티미디어 원리(텍스트+이미지)를 적용한 콘텐츠를 각각 개발하고, 학습자들을 사전지식이 높은 집단과 낮은 집단으로 분류한 다음, 각 집단을 양분하여 두 종류의 스마트 패드용 콘텐츠를 학습하게 하였다. 각 집단의 인지부하 정도와 학업성취도를 측정한 결과, 멀티미디어 원리와 개인차 원리는 인지부하에 유의한 효과를 가져오지 못하였으나, 학업성취도 차원에서는 모두 유의한 효과를 가져왔다. 이러한 연구결과는 PC 모니터보다 제한된 스마트 패드의 화면 크기, 이미지의 성격, 그리고 학습목표의 성격 등에 기인한 것으로 보여지며, 향후 스마트 패드용 콘텐츠 개발에 있어 시사점을 제공할 수 있다.

• Ocean and Polar Research
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• 제30권3호
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• pp.261-275
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• 2008

The profile of a fixed site at station M ($34.77^{\circ}N,\;129.13^{\circ}E$) in the Korea Strait was studied from March 2006 to February 2007. The aim was to understand the relationship between the annual thermal stratification pattern and seasonal variation in phytoplankton community structure. Physicochemical factors including temperature, salinity and nutrient concentrations, which strongly influence the proliferation and diversity of phytoplankton, were measured. The study period was divided into three due to the characteristic of thermohaline structures; mixed I (March-May 2006), stratified (June-November 2006) and mixed II(December 2006-Feburuary 2007). Diatoms dominated during the mixed I (89%) and II (48%) periods, while nanoplankton group occupied over 83% of total population during the stratified period. The dominant species during the mixed I and II was Chaetoceros socialis (47% and 29%, respectively), while during the stratified period Gyrodinium sp.(4%) was the most dominant. Averaged total chl a concentrations during the mixed I and II periods were 0.61 mg $m^{-3}$ and 0.72 mg $m^{-3}$, respectively, which were at least two-fold higher than that during the stratified period (0.30 mg $m^{-3}$). The vertical mixing and convection process of the water column induced nutrient supply from the bottom layer to the euphotic zone. It also led to the dominance of diatoms during the mixed periods, whereas small phytoplankton prevailed over large phytoplankton as stratification blocked the upward movement of nutrients to subsurface during the stratified period. During the mixed I and II periods, microplanktonic chl a dominated concentrations (50% and 48%, respectively), while picoplanktonic chl a occupied over 37% of total chl a during the stratified period.