• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.152-152
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• 2013

Mechanism of energy conversion from chemical to electrical during exothermic catalytic reactions at the metal surfaces has been a fascinating and crucial subject in heterogeneous catalysis. A metal-semiconductor Schottky nanodiode is novel device for direct detection of chemically induced hot electrons which have sufficient energy to surmount the Schottky barrier. We measured a continuous chemicurrent during the hydrogen oxidation under of 760 Torr of O2 and 6 Torr of H2 by using Pt/Si and Pt/TiO2 nanodiodes at reaction temperatures and compared the chemicurrent with the reaction turnover rate. The thermoelectric current was measured by carrying out an experiment under O2 condition for elimination of the background current. Gas chromatograph and source meter were used for measurement of the chemical turnover rate and the chemicurrent, respectively. The correlation between the chemicurrent and the chemical turnover rate under hydrogen oxidation implies how hot electrons generated on the metal surface affect hydrogen oxidation.

• Structural Engineering and Mechanics
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• 제10권4호
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• pp.299-312
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• 2000

The response of an embedded body to dynamic loads is greatly influenced by the reactions of the soil to the motion of the body. The properties of the soil surrounding embedded bodies (e.g., piles) may be different than those of the far-field for a variety of reasons. It may be weakened or strengthened according to the method of installation of piles, or altered due to applying one of the soil strengthening technique (e.g., electrokinetic treatment of soil, El Naggar et al. 1998). In all these cases, the shear strength of the soils and its shear modulus vary gradually in the radial direction, resulting in a radially inhomogeneous soil layer. This paper describes an analysis to compute vertical and torsional dynamic soil reactions of a radially inhomogeneous soil layer with a circular hole. These soil reactions could then be used to model the soil resistance in the analysis of the pile vibration under dynamic loads. The soil layer is considered to have a piecewise, radial variation for the complex shear modulus. The model is developed for soil layers improved using the electrokinetic technique but can be used for other situations where the soil properties vary gradually in the radial direction (strengthened or weakened). The soil reactions (impedance functions) are evaluated over a wide range of parameters and compared with those obtained from other solutions. A parametric study was performed to examine the effect of different soil improvement parameters on vertical and torsional impedance functions of the soil. The effect of the increase in the shear modulus and the width of the improved zone is investigated.

• 한국보육지원학회지
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• 제15권1호
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• pp.1-14
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• 2019

Objective: This study examined the effects of mothers' reactions to children's negative emotions on the children's social power through children's emotional regulation ability. Methods: A total of 339 four-year and five- year old preschoolers, and their mother and teachers in Seoul and Gyeongi participated in the study. Data were analyzed by path analysis using AMOS 21.0 program. Results: The results were as follows: First, mothers' reactions to children's negative emotions were significantly related to children's emotional regulation ability and social power. Also, children's emotional regulation ability was significantly associated with children's social power. Second, mothers' reactions to children's negative emotions had indirect effects on social power - prosocial leadership and social dominance-through children's emotional regulation ability. Conclusion/Implications: The results of this study revealed the mediating role of children's emotional regulation ability between mothers' reactions to children's negative emotions and children's social power. Also, these findings will be helpful in order to understand children's social power and to develop parent education programs.

• 한국콘텐츠학회논문지
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• 제19권1호
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• pp.234-241
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• 2019

의약품을 사용할 때 나타나는 부작용은 국민의 건강을 크게 위협할 수 있다. 현재 의약품 부작용에 대한 보고가 매우 미흡한 것이 현실이다. 이에 현재 약국에서 사용하고 있는 의약품 사용평가(DUR:Drug Utilization Review)에 의약품 부작용 보고를 연계하게 된다면 활성화될 수 있다. 의약품 사용평가가 활성화되어 있는 미국 의약품 관리 체계 연구를 통해 의약품 부작용 보고 활성화 방안을 찾을 수 있다. 약국에서 의약품 관리 프로그램으로 사용되는 'Pharm IT 3000'에서 의약품 부작용 보고의 활성화 방안을 연구해 보았다. 문헌연구와 실제 프로그램 운영 방식 연구를 통해 Pharm IT 3000 처방 조제 현황 항목에 의약품 사용평가를 연동시켜 부작용 보고가 편리하게 되는 방안을 찾게 되었다.

• 인간식물환경학회지
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• 제24권2호
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• pp.209-218
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• 2021

Background and objective: Instagram, an image-based social media, is being used as an important outlet for the communication and place marketing of public spaces. The purpose of this paper was to analyze how types of place-based content affect user reactions (Likes and Comments) on Instagram in order to provide basic data on the operation and utilization of social media by public places such as botanical gardens and arboretums. Methods: A total of 850 posts uploaded to the Instagram account of Kew Gardens from November 6, 2014 to July 3, 2020 were classified using 14 subject codes. Multiple regression analysis was performed to evaluate the user's reaction between the dependent variables ("Likes", "Comments") and the independent variables (14 subject codes). Results: The findings showed that user reactions appear to differ depending on the typology of the content, and "Likes" and "Comments" were presented in independent behavioral reactions. In particular, "close-ups of plants (botanic, macro)," "plant colony (botanic, wide)," "place-specific landscape (building, landscape)," "anniversary" and "information" showed positive impacts on both "Likes" and "Comments"which could lead to electronic word-of-mouth and content sharing. Conclusion: Based on these findings, it can be argued that the typology of a botanical garden's content can be used to determine factors that affect the immediate reactions and enhance engagement with users.

• Bulletin of the Korean Chemical Society
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• 제31권7호
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• pp.1915-1919
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• 2010

Second-order rate constants $(k_N)$ have been measured for reactions of 2,4-dinitrophenyl phenyl carbonate (2) with a series of pyridines in 80 mol % $H_2O$/20 mol % DMSO at $25.0{\pm}0.1^{\circ}C$ and compared with the $k_N$ values reported for the corresponding reactions of 2,4-dinitrophenyl benzoate (1) to investigate the effect of nonleaving group on reactivity and mechanism. The reactions of 2 result in larger $k_N$ values than those of 1. The Br${\o}$nsted-type plot for the reactions of 2 exhibits a downward curvature (i.e., ${\beta}2$ = 0.84 and ${\beta}1$ = 0.16), which is typical for reactions reported to proceed through a stepwise mechanism with a change in rate-determining step. The $pK_a$ at the center of the Br${\o}$nsted curvature, defined as $pK_a{^{\circ}}$, has been found to be 8.5 and 9.5 for the reactions of 2 and 1, respectively. Dissection of $k_N$ into the microscopic rate constants (e.g., $k_1$ and $k_2/k_{-1}$ ratio) has revealed that the reactions of 2 result in larger k1 values than those of 1, indicating that PhO behaves as a stronger electron-withdrawing group than Ph. However, the $k_2/k_{-1}$ ratio has been found to be independent of the electronic nature of Ph and PhO.

• Bulletin of the Korean Chemical Society
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• 제32권6호
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• pp.1951-1956
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• 2011

A kinetic study is reported on nucleophilic substitution reactions of 4-nitrophenyl nicotinate 5 and isonicotinate 6 with alkali metal ethoxide EtOM (M = K, Na, and Li) in anhydrous ethanol at $25.0{\pm}0.1^{\circ}C$. Plots of pseudo-first-order rate constant $k_{obsd}$ vs. EtOM concentration exhibit upward curvature for the reactions of 5 and 6 with EtOK and EtONa but are almost linear for those with EtOLi. Dissection of $k_{obsd}$ into $k_{EtO^-}$ and $k_{EtOM}$ (i.e., the second-order rate constant for the reaction with dissociated $EtO^-$ and ion-paired EtOM, respectively) has shown that $k_{EtOK}$ ${\geq}$ $k_{EtONa}$ > $k_{EtO^-}$ but $k_{EtOLi}$ < $k_{EtO^-}$. It has been concluded that $K^+$ and $Na^+$ ions catalyze the reactions by increasing the electrophilicity of the carbonyl carbon atom through formation of a 4-membered cyclic transition state $TS_3$ or $TS_4$. However, $M^+$ ion catalysis has been found to be much less significant for the reactions of 5 and 6 than for the corresponding reactions of 4-nitrophenyl picolinate 4, which was reported to proceed through a 5-membered cyclic transition state $TS_2$. Although 5 and 6 are significantly more reactive than 4-nitrophenyl benzoate 3, the reactions of 5 and 6 result in smaller $k_{EtOK}/k_{EtO^-}$ ratios than those of 3. The electron-withdrawing ability of the nitrogen atom in the acyl moiety of 5 and 6 has been suggested to be responsible for the increase in reactivity and the decrease in the $k_{EtOK}/k_{EtO^-}$ ratio.

• Bulletin of the Korean Chemical Society
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• 제32권4호
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• pp.1165-1169
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• 2011

Second-order rate constants ($k_N$) have been measured spectrophotometrically for nucleophilic substitution reactions of 2,4-dinitrophenyl phenyl thionocarbonate 4 with a series of Z-substituted pyridines in 80 mol % $H_2O$/20 mol % DMSO at $25.0{\pm}0.1^{\circ}C$. The Br${\o}$nsted-type plot for the reactions of 4 exhibits downward curvature (i.e., ${\beta}_1$ = 0.21 and ${\beta}_2$ = 1.04), indicating that the reactions proceed through a stepwise mechanism with a change in rate-determining step. It has been found that 4 is less reactive than its oxygen analogue, 2,4-dinitrophenyl phenyl carbonate 3, although the thionocarbonate is expected to be more electrophilic than its oxygen analogue. The $pK_a$ at the center of the Br${\o}$nsted curvature, defined as $pK_a^o$, has been analyzed to be 6.6 for the reactions of 4 and 8.5 for those of 3. Dissection of $k_N$ into the microscopic rate constants $k_1$ and $k_2/k_{-1}$ ratio has revealed that the reactions of 4 result in smaller $k_1$ values but larger $k_2/k_{-1}$ ratios than the corresponding reactions of 3. The larger $k_2/k_{-1}$ ratios have been concluded to be responsible for the smaller $pK_a^o$ found for the reactions of 4.

• 한국미생물·생명공학회지
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• 제47권4호
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• pp.536-545
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• 2019

Cytochrome P450 (P450 or CYP) is involved in the metabolism of endogenous and exogenous compounds in most organisms. P450s have great potential as biocatalysts in the pharmaceutical and fine chemical industries because they catalyze diverse oxidative reactions using a wide range of substrates. The high-cost nicotinamide cofactor, NADPH, is essential for P450 reactions. Glucose-6-phosphate dehydrogenase (G6PDH) has been commonly used in NADPH-generating systems (NGSs) to provide NADPH for P450 reactions. Currently, only two G6PDHs from Leuconostoc mesenteroides and Saccharomyces cerevisiae can be obtained commercially. To supply high-cost G6PDH cost-effectively, we cloned the cytosolic G6PDH gene of Solanum lycopersicum (tomato) with 6xHis tag, expressed it in Escherichia coli, and purified the recombinant G6PDH (His-G6PDH) using affinity chromatography. In addition, enzymatic properties of His-G6PDH were investigated, and the His-G6PDH-coupled NGS was optimized for P450 reactions. His-G6PDH supported CYP102A1-catalyzed hydroxylation of omeprazole and testosterone by NADPH generation. This result suggests that tomato His-G6PDH could be a cost-effective enzyme source for NGSs for P450-catalyzed reactions as well as other NADPH-requiring reactions.

• Asian Pacific Journal of Cancer Prevention
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• 제13권4호
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• pp.1209-1215
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• 2012

Background and Aim: Oxaliplatin hypersensitivity is a well-known adverse reaction but the prevalence varies and data for frequency and clinical features have not been reported for Korea. Here we evaluates the prevalence and risk factors for hypersensitivity reactions to oxaliplatin after chemotherapy. Methods: Clinical information on all patients treated with oxaliplatin was retrospectively reviewed in electronic medical records between August 2009 and July 2010 in Seoul National University Bundang Hospital. Patients who experienced hypersensitivity reactions to oxaliplatin were compared with those who did not. Results: A total of 393 patients received oxaliplatin, with 42 (10.7%) experiencing hypersensitivity reactions including three cases of anaphylaxis. Median cycle of the first hypersensitivity reaction was 8. Reactions correlated with lower dexamethasone doses. Other variables were not significant. Conclusions: The prevalence of hypersensitivity reactions was 10.7%, symptoms being mostly mild and cutaneous. Lower dexamethasone doses could be a predictor for hypersensitivity reactions to oxaliplatin.