• Korean Journal of Materials Research
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• v.32 no.4
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• pp.186-192
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• 2022

Collagen is one of the most widely used biological materials in medical design. Collagen extracted from marine organisms can be a good biomaterial for tissue engineering applications due to its suitable properties. In this study, collagen is extracted from fish skin of Ctenopharyngodon Idella; then, the freeze drying method is used to design a porous scaffold. The scaffolds are modified with the chemical crosslinker N-(3-Dimethylaminopropyl)-N'-ethyl carbodiimide hydrochloride (EDC) to improve some of the overall properties. The extracted collagen samples are evaluated by various analyzes including cytotoxicity test, SDS-PAGE, FTIR, DSC, SEM, biodegradability and cell culture. The results of the SDS-PAGE study demonstrate well the protein patterns of the extracted collagen. The results show that cross-linking of collagen scaffold increases denaturation temperature and degradation time. The results of cytotoxicity show that the modified scaffolds have no toxicity. The cell adhesion study also shows that epithelial cells adhere well to the scaffold. Therefore, this method of chemical modification of collagen scaffold can improve the physical and biological properties. Overall, the modified collagen scaffold can be a promising candidate for tissue engineering applications.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.2
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• pp.145-151
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• 2014

Purpose: The material properties of contact lenses were measured by varying the amounts of an initiator and a cross-linking agent that are the basis for the manufacture of contact lenses, and the drug delivery effects depending on the material properties of contact lenses were compared. Methods: Contact lens samples were manufactured using HEMA by varying the concentration of the cross-linking agent and the initiator. To investigate the changes in physical characteristics depending on the material properties, the results of the experiments on the amount of drug elution, water content, refractive index, and the amount of protein adsorption were compared. Results: For the contact lenses manufactured by varying the amount of the initiator, the water content hardly changed, and the refractive index also hardly changed. The amount of drug elution was not much affected by the changes in the initiator, but the amount of elution increased as the water content increased. The amount of protein adsorption was hardly affected by the changes in the initiator, but the amount of adsorption increased as the water content decreased. Conclusions: The changes in the properties were hardly affected by the changes in the amount of the initiator, but were significantly affected by the changes in the amount of the cross-linking agent. As the amount of the cross-linking agent increased, the water content decreased, while the refractive index increased. Also, when the water content increased, the amount of drug elution increased, while the amount of protein adsorption decreased.

• Journal of Energy Engineering
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• v.20 no.3
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• pp.171-177
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• 2011

PVA/GLA/$Al_2O_3{\cdot}3SiO_2$ composite membranes were prepared through the reaction polyvinyl alcohol (PVA) with glutaraldehyde (GLA) as a cross-linking agent and subsequently adding aluminum silicate ($Al_2O_3{\cdot}3SiO_2$) as an inorganic material. The water uptake decreased as the GDL contents increased due to cross-linking process of PVA with GDL, and the ion conductivity increased as the $Al_2O_3{\cdot}3SiO_2$ contents increased in PVA/GLA/$Al_2O_3{\cdot}3SiO_2$ composite membranes. The cross-linking structure of the polymers was confirmed using IR and the tendency of water uptake. The thermal analysis of the copolymers was carried out by TGA. TGA results showed that PVA/GLA composite membrane were more heat-resistant than PVA due to the cross-linking of PVA, and the heat stability of the composite membranes improved much more as the concentration of $Al_2O_3{\cdot}3SiO_2$ increased. Membranes prepared in this study seem to be have thermal stability and increase a tendency of the cation conductivity up to $60^{\circ}C$, but to be exhibit lower performance tendency at over $90^{\circ}C$. Therefore, it is necessary to do more aggressive effort to explore the possibility of application as an ion-conductive composite electrolyte.

• Food Science and Preservation
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• v.20 no.4
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• pp.539-545
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• 2013

Effects of RS4 type resistant corn starch on the quality characteristics of cookies were investigated by physicochemical, instrumental and sensory evaluation. The resistant starch was made by cross-linking of corn starch as following; corn starch slurry was annealed at pH 2.0 and $50^{\circ}C$ for 2 h followed by the cross-linking reaction. The cross-linking reaction was performed at $50^{\circ}C$ for 12 h in the presence of 1.2%/st.ds NaOH, 10%/st.ds sodium sulfate and 10%/st.ds of sodium trimetaphosphate (STMP)/sodium tripolyphosphate (STPP) mixture. Dietary fiber content of the resistant starch was estimated to be 73.8% by the AOAC method. For quality characteristics, dough pH decreased with the increase of the resistant starch content and spread factor decreased a little at 20% of the resistant starch. The moisture content and L value of cookies increased with the increase of the resistant starch content. However, the hardness and fracturability decreased with the increase of the resistant starch content. In the sensory evaluation, no significant differences were observed between the two cookies with or without the resistant starch. The results of this study suggest that the RS4 type resistant corn starch can be a good ingredient to increase dietary fiber content in cookies without changes of their qualities.

• Journal of KIISE:Computing Practices and Letters
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• v.7 no.2
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• pp.183-192
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• 2001

In a development environment for embedded system with a connection between host and target system, the linker of host system links the cross-compiled object file and modules of target system and downloads the linked object file to the target system. In this research, we separate this linker into the module dependent on object file format and the module independent on object file format. The dependent module gets the linking information independent on file format from the object file, and the independent module actually does the linking process with this linking information_ This separation can improve the portability of development environment for a target system_ Also, our linker does the incremental remote linking that applies relocation not only to the obj ect file to be loaded but also to target's modules to have been loaded_ This incremental remote linking can reduce a linking time than linking by the united modules because of linking by module. The result of measuring linking time for SPEC95 integer benchmarks shows an average of reduction rates of 64.90%. Also, incremental remote linking can improve the comfortability of users who develop programs because users do not consider a downloading order of linking object files. Currently, we developed this linker in the embedded application development environment ESTO [1] to be prepared for a commercial product.

• Membrane Journal
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• v.21 no.3
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• pp.270-276
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• 2011

A nascent membrane was prepared by using the solution evaporation method with a solution of sPEEK, EdAn (cross-linking reagent), and PEA (grafting reagent) in DMAc. Then, after the imination and sulfonation process the cross-linked and grafted ion-exchange membrane, CG-sPEEK, was obtained. The sulfonation and imination reactions were confirmed by FTIR analysis. In order to evaluate the possibility of prepared membrane for the use of an ion-exchange membrane in PEMFC, proton conductivity, water uptake and volume change were measured and compared with a commercial membrane, Nafion 115. It was revealed that since the proton conductivity (0.17 S/cm) of prepared membrane were much higher than those of Nafion 115 (0.10 S/cm) the prepared membrane could be used for the ion-exchange membrane in PEMFC. However, the high water uptake (130%) of CG-sPEEK should be reduced for the dimension stability.

• YAKHAK HOEJI
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• v.55 no.1
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• pp.69-74
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• 2011

Hyaluronic acid (HA) is a natural polymer consisting of disaccharide units of D-glucuronic acid and N-acetyl-D-glucosamine. It has a great potential and success in cosmetic and biomedical applications. However, native HA is highly soluble and easily metabolized by enzymes such as hyaluronidase. Thus, various studies have been reported on modifying the physicochemical properties of HA, while maintaining its biocompatibility. For controlled drug delivery, many trials for fabricating HA microspheres were achieved under chemical reaction. The HA microspheres fabricated to improve the physical stability of HA using adipic acid dihydrazide (ADH) by cross-linking reaction has been reported earlier, however it lacks the desired physical stability and rapidly decomposes by swelling or enzymes. Therefore, we prepared double cross-linked HA microspheres (DC-HA microspheres) and alginate containing HA microspheres (AC-HA microspheres) to enhance its physicochemical properties. DC-HA microspheres were prepared using trisodium trimetaphosphate (STMP) under crosslinking reaction after ADH cross-linking reaction. AC-HA microspheres were prepared by adding alginate as a networking polymer. These microspheres were characterized by morphology, particle size, zeta potential, stability against hyaluronidase. Results showed that the DC-HA and AC-HA microspheres are more stable than that of HA microspheres.

• Journal of Korean Clinical Nursing Research
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• v.22 no.2
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• pp.173-182
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• 2016

Purpose: This study investigated the linking words of nurse which were presented together with nurse on phrase, clauses or sentence of documents or conversations in the Internet portals and social media. Methods: The linking words with nurse were calculated by the number of presentation on conversations or documents, in Google, Daum, Naver, Twitter and Facebook. The changes of characteristics and the trend of yearly changes of major linking words of nurse were investigated by the type of media. In order to identify the meaning of the words, clustering of the collected linking words by categories was analysed and the characteristics of each cluster were classified. Results: A total number of reviewed linking words was 17,399,711 and the most frequently presenting words were hospital, work and person. The words related to people were the most highly presented and the next were those of emotion, professional and place respectively. Conclusion: With analysing the trends of changes and characteristics of words by yearly base and clusters, we attempted to investigate the image of nurse that the public think and feel about nurse.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.11a
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• pp.64-67
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• 2004

• Korean Membrane Journal
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• v.5 no.1
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• pp.10-17
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• 2003

1,3,5-Sustitituted polyphenylene type dendrimers were synthesized. The dendrimer was heated in cone. H$_2$SO$_4$ at 120$^{\circ}C$. The reaction mixture was precipitated to ether after simple filtration to get para-sulfonated dendrimer as the chief product. To give mechanical properties to the sulfonated dendrimer, it was partially cross-linked with phenyl ether in the medium of P$_2$O$\sub$5/ and CH$_3$SO$_3$H.