• Membrane Journal
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• v.18 no.2
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• pp.116-123
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• 2008

Proton conductive hybrid nanocomposite polymer electrolyte membranes comprising polystyrene-5-poly (hydroxyethyl methacrylate) (PS-b-PHEMA), sulfosuccinic acid (SA) and phosphotungstic acid (PWA) were prepared by varying PWA concentrations. The PHEMA block was thermally crosslinked by SA via the esterification reaction between -OH of PHEMA and -COOH of SA. Upon the incorporation of PWA into the diblock copolymer, the symmetric stretching bands of the $SO_3^-$ group at $1187cm^{-1}$ shifted to a lower wavenumber at $1158cm^{-1}$, demonstrating that the PWA particles strongly interact with the sulfonic acid groups of SA. When the concentration of PWA was increased to 30wt%, the proton conductivity of the composite membrane at room temperature increased from 0.045 to 0.062 S/cm, presumably due to the intrinsic conductivity of the PWA particles and the enhanced acidity of the sulfonic acid in the membranes. The membrane containing 30wt% of PWA exhibited a proton conductivity of 0.126 S/cm at $100^{\circ}C$. Thermal stability of the composite membranes was also enhanced by introducing PWA nanoparticles.

• Journal of Applied Biological Chemistry
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• v.53 no.4
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• pp.225-231
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• 2010

To understand the inhibitory activity with changing hydroxyl substituents ($R_l-R_9$) of polyhydroxy substituted 2-phenyl-l,4-benzopyrone analogues (1-25) against tyrosinase (PDB ID: oxy-form; 1WX2), molecular docking and the three dimensional quantitative structure-activity relationships (3D-QSARs: Comparative molecular field analysis (CoMFA) & Comparative molecular similarity indices analysis (CoMSIA)) were studied quantitatively. The statistically best models were CoMFA 1 and CoMSIA 1 model from the results. The optimized CoMSIA 1 model with the sensitivity of the perturbation and the prediction produced ($dq^2'/dr_{yy'}^2$=1.009 & $q^2$=0.51l) by a progressive scrambling analysis were not dependent on chance correlation. The inhibitory activities with optimized CoMSIA 1 model were dependent upon electrostatic factor (51.4%) of substrate molecules. Contour mapping the 3D-QSAR models to the active site of tyrosinase provides new insight into the interaction between tyrosinase as receptor and 2-phenyl-l,4-benzopyrone analogues as inhibitor. Therefore, the results will he able to apply to the optimization of a new potent tyrosinase inhibitors.

• Culinary science and hospitality research
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• v.15 no.3
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• pp.356-372
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• 2009

The purpose of this study is to study academic tendency in the researches on the service quality of Korean restaurants by analyzing the studies related to the service quality of Korean restaurants. As a result of this study, the studies related to the service quality of Korean restaurants, included in 7 academic journals selected, are totally 26 articles. Among them, there are 14 researches targeting medium-large size Korean restaurants with more than 100 seats. In the methodological aspect, the scales, which were used most frequently in measuring the service quality of Korean restaurants, were indicated to be SERVQUAL in Parasuraman et al.(1988), DINESERV in Stevens et al.(1995) and Brady & Cronin(2001)'s scale. Also, as a result of examining the tendency of researches related to the service quality in Korean restaurants in the contextual aspect, the interaction quality between employees and customers out of customers' perceived service quality was surveyed to have greater influence upon customers' behavioral reaction than the physical quality or technical quality. Consequently, in order to conduct an institutional research through examining the service quality in Korean restaurants, understanding the customers' perceived service quality needs to be implemented preferentially with a systematically verified scale. Moreover, such researches on the service quality of Korean restaurants appear to focus on specific subjects. Thus, in order to escape from this tendency, it is necessary to explore creative research subjects and design diversely and scientifically analytical methods.

• Korean Chemical Engineering Research
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• v.43 no.5
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• pp.632-636
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• 2005

In this work, the effect of chemical treatments on surface properties of SiC was investigated in thermal and mechanical interfacial behaviors of SiC/PMMA nanocomposites. The acid/base value, contact angles, and FT-IR analysis were performed for the study of surface characteristics of the SiC studied. The thermal stabilities of the SiC/PMMA nanocomposites were investigated by thermogravimetric analysis (TGA). Also the mechanical interfacial properties of the composites were studied in critical stress intensity factor ($K_{IC}$) and critical strain energy release rate ($G_{IC}$) measurements. As a result, the acidically treated SiC (A-SiC) had higher acid value than that of untreated SiC (V-SiC) or basically treated SiC (B-SiC). The acidic solution treatment led to an increase in surface free energy of the SiC, mainly due to the increase of its specific component. Thermal and mechanical interfacial properties of the SiC/PMMA nanocomposites, including initial decomposition temperature (IDT), $K_{IC}$, and $G_{IC}$ had been improved in the acidic treatment on SiC. This was due to the improvement in the interfacial bonding strength, resulting from the acid-base interfacial interactions between the fillers and polymeric matrix.

• Journal of Life Science
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• v.30 no.5
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• pp.483-490
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• 2020

The ubiquitin system uses ligases and deubiquitinases (DUBs) to regulate ubiquitin position on protein substrates and is involved in many biological processes which determine stability, activity, and interaction of the target substrate. DUBs are classified in six groups according to catalytic domain, namely ubiquitin-specific proteases (USPs); ubiquitin C-terminal hydrolases (UCHs); ovarian tumor proteases (OTUs); Machado Joseph Disease proteases (MJDs); motif interacting with Ub (MIU)-containing novel DUB family (MINDY); and Jab1/MPN/MOV34 metalloenzymes (JAMMs). Otubain 1 (OTUB1) is a DUB in the OTU family which possesses both canonical and non-canonical activity and can regulate multiple cellular signaling pathways. In this review, we describe the function of OTUB1 through regulation of its canonical and non-canonical activities in multiple specifically cancer-associated pathways. The canonical activity of OTUB1 inhibits protein ubiquitination by cleaving Lys48 linkages while its non-canonical activity prevents ubiquitin transfer onto target proteins through binding to E2-conjugating enzymes, resulting in the induction of protein deubiquitination. OTUB1 can therefore canonically and non-canonically promote tumor cell proliferation, invasion, and drug resistance through regulating FOXM1, ERα, KRAS, p53, and mTORC1. Moreover, clinical research has demonstrated that OTUB1 overexpresses with high metastasis in many tumor types including breast, ovarian, esophageal squamous, and glioma. Therefore, OTUB1 has been suggested as a diagnosis marker and potential therapeutic target for oncotherapy.

• Journal of Science Education
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• v.32 no.2
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• pp.17-32
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• 2008

The purpose of this study was to analyze the use of the e-learning courseware which is about the properties of earth environmental change. I made these materials using Lectora program, and to have more visual effect, I used movies and animations as much as possible. A lot of movies and pictures are added to help student understand the geographical age. Especially the forms of performance test questions are various, and student can check the answer right after taking test. Because of this, they can get a immediate feedback. In addition, this allows you to adapt yourself to the age of information by using the internet. Every plug-in is already linked together, so you only need to once. Pictures and moving reflections can be edited with ease. I hope this study will provide valuable aid for the education of earth science and a chance to develop better materials.

• KSBB Journal
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• v.17 no.2
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• pp.153-157
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• 2002

A fusion protein, consisting of a human epidermal growth factor as the recognition domain and human angiogenin as the toxin domain, can be used as a targeted therapeutic against breast cancer cells among others. The fusion protein was expressed as an inclusion body in recombinant E. coli, yet when the conventional solution-phase refolding process was used the refolding yield was very low due to severe aggregation, probably because of the opposite surface charge resulting from the vastly different pl values of each domain. Accordingly the solid-phase refolding process, which exploits the ionic interactions between a solid matrix and the protein, was tried, however the ionic binding yield was also very low regardless of the resins and pH conditions used. Therefore, to provide a higher affinity toward the solid matrix, six Iysine residues were tagged to the N-terminus of the hEGF domain. When cation exchange resins, such as heparin- or CM-Sepharose, were used as the matrix, the adsorption capacity increased 2.5~3-fold and the subsequent refolding yield increased nearly 15-fold compared to the conventional process. A similat result was also obtained when an Ni-NTA metal affinity resin was used.

• Journal of the Korean Chemical Society
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• v.45 no.5
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• pp.442-447
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• 2001

The charge-transfer compound (OMTTF)AuCl$_4$ was prepared from the direct reaction of octamethylenethiafulvalene (OMTTF) with HAuCl$_4{\cdot}xH_2$O in THF. (OMTTF)$_2PtCl_4$, (OMTTF)_2IrCl_6{\cdot}2H_2$O, and (OMTTF)Os$Cl_5{\cdot}THF$ were also formed using $H_2PtCl_6{\cdot}xH_2O$, $H_2IrCl_6{\cdot}xH_2O$ and $H_2OsCl_6$, respectively. The prepared compounds were characterized by magnetic (EPR, magnetic susceptibility), spectroscopic (IR, UV-Vis), electrochemical (CV) methods, and the powdered electrical conductivity measurement. The powdered electrical conductivities at room temperature were ~$10^{-7}S{\cdot}cm^{-1}$. The experimental results show that $OMTTF^+$ monocation radicals exist in all of the prepared compounds. The redox potential of OMTTF supports that $OMTTF^+$ is relatively stable. The magnetic properties indicate that there are significant magnetic interactions between the localized odd electrons on the central metal (Ir and Os) ions and the odd electrons resided on $OMTTF^+$ cation radicals in both (OMTTF) $_2IrCl_6{\cdot}2H_2O$ and (OMTTF)$OsCl_5{\cdot}THF$.

• Archives of design research
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• v.11 no.1
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• pp.173-184
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• 1998

This study deals with the visual quality in the future urban landscape and architectural environment, and as such, aims to identify a scientific and objective aesthetic and visual quality from the perspective of empirical aesthetics. The empirical aesthetics provides a framework that can be utilized in understanding human perception, consciousness, and behavior and a way to categorize the visual quality and to explain and predict its effect. The study examines various theories on environmental perception, cognition, and some new approaches to environmental aesthetics, and tries to present aesthetic properties that can be applied to environmental design. First, the aesthetic experience in visual perception can be defined as a combined effect of psychobiological properties and human activity, i.e. an interaction between the formal and symbolic signs in environment and the conceptual framework of man. The effect of visual quality differs and varies a great deal, depending on the sociocultural, personal and collective value system, so it is hard to define it in absolute terms. Second, the impact of visual quality and its aesthetic effect has to do with pleasure, preference, the aptitude for survival, and self regulation. Third, aesthetics is one of the areas that can benefit a great deal from an interdisciplinary approach. and an empirical study such as this can be used as a basis for design, planning, and evaluation.

• Elastomers and Composites
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• v.38 no.4
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• pp.316-325
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• 2003

The blends of waste-polyethylene (W-PE)/waste-ethylene vinyl acetate copolymer (W-EVA) with inorganic and phosphorous flame retardants (i.e., aluminium hydroxide, magnesium hydroxide, and so on) were prepared by melt mixing techniques at different compositions and foamed. The flame retardancy and foaming properties of the blends, limiting oxygen index (LOI), heat release rate (HRR), carbon monoxide yield (COY), total heat release (THR), effective heat of combustion (EHC), expandability and cell structure were investigated using cone calorimeter, SEM, LOI tester and polarizing microscope. When the composition ratios of the W-PE/W-EVA blends were 50/50 (w/w), and the ranges of the flame retardants contents were $175{\sim}220 phr$, we could obtain foams with the uniform and closed cell, high expandability (1900 % or more), high LOI, and low HRR values. These results depend on crosslinking and loaming conditions, a char formation and smoke suppressing effect. Aluminium hydroxide had more effect in the increase of LOI than magnesium hydroxide, while magnesium hydroxide considerably affected the decrease of HRR and COY.