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Changyong Choi,Eunju Kim 한국학술연구원 2024 Korea Observer Vol.55 No.3
This study examines the dynamics of public support for international development policies in the United States and South Korea, focusing on the distinctions between normative and substantial support. Normative support is based on agreement with the policy's importance due to shared values or beliefs, while substantial support involves a willingness to allocate resources for implementation. Utilizing surveys and logit analysis, the research highlights the complex interplay between universal factors like political ideology and self-interest and specific factors such as global citizenship. The study finds that a higher sense of global community significantly boosts normative and substantial support. This nuanced analysis offers valuable insights for enhancing public support for international policies, providing critical implications for policymaking and future research.
DNA delivery using low molecular water-soluble chitosan nanocomplex as a biomedical device
Choi, Changyong,Kim, Dong-Gon,Jang, Min-Ja,Kim, Tae-Hyeong,Jang, Mi-Kyeong,Nah, Jae-Woon Wiley Subscription Services, Inc., A Wiley Company 2006 Journal of applied polymer science Vol.102 No.4
<P>We investigate the potential of low molecular water-soluble chitosan (LMWSC), LMWSC–methoxy polyethylene glycol (MPEG) [LCP], and LMWSC–MPEG–cholesterol (LCP–Ch) as a gene carrier. LMWSC with free-amine group was formed at the low weight ratio, above a 1:2 weight ratio of plasmid DNA:LMWSC. LCP and LCP–Ch achieved complex formation of above 1:8 and 1:24 by reacting with MPEG and cholesterol (Ch) on the amine-group, respectively. Particle sizes at the pH 6.5 and 7.0 were about 100–120 nm and 120–160 nm, respectively. The surface charge of the complex also depended on the pH. At pH 6.5, the surface charge of the complex was higher than that at pH 7.0. The zeta potential of the LCP modified with MPEG or of the LCP-Ch modified with cholesterol has lower positive value than that of LMWSC because of the decrease of the positive charge. The morphologies of the complexes by transmission electron microscope were of spherelike shape with the average diameters of about 100–150 nm. Among the three gene carriers, LCP–Ch/plasmid DNA showed the highest gene expression owing to the hydrophobic interaction between cell surface and cholesterol. No cytotoxicity was observed in the gene carriers investigated in this study at various concentrations. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3545–3551, 2006</P>
Dyeability of Polygoum Tinctoria against Fabrics according to Various Dyeing Conditions
Choi, Changyong,Yang, Suk-Hyang,Nah, Jae-Woon 한국공업화학회 2004 응용화학 Vol.8 No.1
The natural dye substances largely consist of plant, animal and mineral materials, which we can easily and naturally be obtained all around us. It has been widely used all around the world for numerous years. Indigo, as a blue pigment, has been known as one of the oldest natural dyes. Generally, natural dyes have moderate colors and are environmentally friendly, while harmful mordants must be used for fixing them and obtaining a full color range on fabrics and it is very hard to improve K/S of the dyeing and mordanting. In this study, physicochemical characterization of polygoum tinctoria dye substance was investigated, and polygoum tinctoria dyeing was carried out various fabrics according to the various dyeing conditions - fermentation temperature, dyeing temperature, dyeing time, and kinds and amounts of alkali. And then the values of K/S according to dyeing conditions were investigated by colorimeter. Also we investigated to dyefastness against the light, washing, perspiration and friction by KS(Korea Industrial Standard).
Choi, Changyong,Kim, Tae-Hyoung,Chae, Su Young,Choi, Hey Young,Kim, Dong-Gon,Kwon, Joong-Kuen,Nah, Jae-Woon 한국공업화학회 2004 응용화학 Vol.8 No.1
Thermosensitive nanoparticles were prepared by self-assembly of two different poly(ε-caprolactone)(PCL) based amphiphilic block copolymers of PEG-PCL and poly(N-isopropylacrylamide)-PCL (PNIPAAm-PCL). The nanoparticles, prepared by dialysis method with different PNIPAAm-PCL contents, showed different physicochemical properties such as lower critical solution temperature (LCST), particle size, and critical aggregation concentration (cac), measured by ¹H NMR, DSC, dynamic light scattering (DLS), and fluorescence spectroscopy.
Choi, Changyong,Kim, Tae-Hyeong,Chae, Su Young,Kim, Dong-Gon,Kwon, Joong-Kuen,Nah, Jae-Woon 한국공업화학회 2004 응용화학 Vol.8 No.2
To prepare nanoparticles, which are thermosensitive, biocompatible, and biodegradable, the well-defined PNIPAAm-PCL and PEG-PCL block copolymers were synthesized by ring-opening polymerization of c-caprolactone using mPEG-OH and PNIPAAm-OH and characterized by ¹H-NMR and GPC. Thermosensitive nanaparticles according to various ratios of PNIPAAm-PCL and PEG-PCL were prepared by a solvent evaporation method. The nanoparticles showed composition dependent physicochemical properties such as lower critical solution temperature, particle size, and critical aggregation concentration. Then, the nanoparticles were introduced into drug delivery systems using hydrophobic model drug of clonazepam. The drug release behaviors from nanoparticles were investigated.