• Polymer(Korea)
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• v.36 no.3
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• pp.338-343
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• 2012

Interfacial properties of commercially available soft contact lens hydrogels were studied to understand thermodynamic phenomena of protein adsorption. Hydrogel particles ($1{\times}1mm^2$) with varying water wettability were exposed to bovine serum albumin solutions for an hour. The remained albumin solutions were analyzed with Bradford assay method. The amount of protein adsorbed to hydrogels increased with protein solution concentrations following Langmuir isotherm. The partition coefficient ($P$) and Gibbs free energy cost of dehydrating the surface region by protein displacement upon adsorption increased with increasing hydrophilicity of contact lens. Understanding of physical chemistry in protein adsorption to contact lens materials enabled elucidating relationships between surface energy and albumin adsorption capacity.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.3
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• pp.301-309
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• 2015

Purpose: This study was aimed to design new schematic eyes for presbyopia using the Navarro eye model and clinical data. Methods: We collected clinical data of eye-optical parameters of males in their age of 40, 50, and 60 from previous studies, and designed schematic eyes for presbyopia using the ZEMAX program. Results: The presbyopic process and features of the designed schematic eyes well accorded with the clinical data of previous studies. Conclusions: On the basis of the Navarro eye model, a finite schematic eyes for presbyopia were newly designed corresponding with clinical data.

• Journal of Integrative Natural Science
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• v.9 no.4
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• pp.249-254
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• 2016

This study evaluated the physical and optical characteristics of hydrophilic ophthalmic polymer with addition of 2-methacryloyloxyethyl phosphorylcholine in the basic hydrogel ophthalmic lens material, and in particular, the utility of 2-methacryloyloxyethyl phosphorylcholine as an ophthalmic contact lens material for ophthalmologic devices was investigated. In this study 2-methacryloyloxyethyl phosphorylcholine were used as additives. For the preparation of hydrogel lens 2-hydroxyethyl methacrylate, methyl methacrylate, acrylic acid and a cross-linker EGDMA were copolymerized in the presence of AIBN as an initiator. The physical properties of the produced polymers were measured as followings. The refractive index of 1.433~1.393, water content of 35.95~53.16%, contact angle of $70.6{\sim}51.24^{\circ}$, UVB transmittance of 81.2~82.4%, UV-B transmittance of 81.2~82.4% and visible transmittance of 91.4~92.2% were obtained. Also, in case of protein absorption, the measurement showed that absorbance of Reference and MPC-10 sample was 0.2598 and 0.2250 respectively. Based on the results of this study, ophthalmic lens material containing 2-methacryloyloxyethyl phosphorylcholine is expected to be used usefully as a material for high wettability and inhibitor of protein adsorption for ophthalmic hydrogel lens.

• Journal of Integrative Natural Science
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• v.11 no.2
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• pp.113-120
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• 2018

This study was planned to prepare the high strength hydrogel ophthalmic lens containing isocyanate group and nanoparticles. HDI with carbon nanoparticles were used as additives for the basic combination of HEMA, MA and MMA, and the materials were copolymerized with EGDMA as the cross-linking agent and AIBN as the initiator. The mixture was heated at $100^{\circ}C$ for an hour to produce the high performance hydrogel ophthalmic lens by cast mold method. Measurement of the physical characteristics of the produced material showed that the refractive index was in the range of 1.4027~1.4600, water content 25.21~44.01%, contact angle $54.18{\sim}72.94^{\circ}$, visible light transmittance 53.03~92.09%, and tensile strength 0.1024~0.2359 kgf and breaking strength was 0.0872~0.2825 kgf. The results showed an increase of refractive index while the decrease in water content. And also, the breaking strength was highest when the addition ratio of HDI was 5%(wt). As a result of the absorbance measurement, no significant difference was observed in all the samples, so it can be judged that the stabilization of nanoparticles in the polymer was maintained.

• Korean Journal of Environmental Biology
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• v.28 no.1
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• pp.14-19
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• 2010

Angiogenesis is an important event involved in cell growth and wound healing process. However, the imbalance of growth factors causes diseases, such as ocular, inflammatory diseases. One of treatment of these diseases is to suppress the formation of blood vessels. Function and mechanism of gold nanoparticles (AuNPs) in the formation of blood vessels is not yet proved. Pigment epithelium derived factor (PEDF) is currently being offered anti-angiogenic materials. In this study, we postulated that AuNPs might have the ability to inhibit angiogenesis, the pivotal step in tumor growth, invasion and metastasis. We have demonstrated that AuNPs could inhibit vascular endothelial growth factor (VEGF) induced cell proliferation, angiogenesis in bovine retinal endothelial cells.

• Polymer(Korea)
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• v.38 no.2
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• pp.220-224
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• 2014

Protein adsorption kinetics was studied with the amount of proteins adsorbed to contact lens hydrogels over time scales. Hydroxyethylmethacrylate (HEMA) and silicone hydrogels were dipped in protein solutions (albumin or IgG) and adsorption amounts were measured over time scales. The amount of protein adsorbed to both hydrogel types increased rapidly in 10 min, and remained consistently in 90 min. Decreasing interfacial energetics was taken slowly up to an hour in spite of rapid diffusion of protein molecules. This is due to the fact that water deprivation from three dimensional interphase initially formed by protein diffusion took over an hour. Interpretation of adsorption kinetics on contact lens hydrogels was discussed with understanding of relationship between surface energy and protein adsorption capacity.

• Korean Journal of Environmental Agriculture
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• v.30 no.2
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• pp.202-208
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• 2011

BACKGROUD: ${\alpha}$- and ${\beta}$- Endosulfan isomers of endosulfan, an endocrine disrupting chemical, are widely used cyclodiene organochlorine pesticide in worldwide, and it has widespread application in agriculture and can contaminate river-system as runoff from soil or aerial deposition METHOD AND RESULTS: In this study, an attempt was made to isolate an endosulfan degrading fungus from endosulfan-polluted agricultural soil. Through repetitive enrichment and successive subculture in media containing endosulfan and its metabolites as the sole carbon source, a fungus designated KEF-1 was isolated. Based on phylogenetic analysis, strain KEF-1 was assigned to the genus Eutypella. Also, the ITS (internal transcribed spacer) sequences of KEF-1 were submitted to GenBank under accession number EF581006. In potato dextrose broth containing 8 ${\mu}g$/mL endosulfan, strain KEF-1 completely degraded the endosulfanin 12 days. CONCLUSION: These results suggested that Eutypella sp. KEF-1 has potential as a biocatalyst for endosulfan bioremediation

• Journal of the Korean Chemical Society
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• v.62 no.2
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• pp.93-98
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• 2018

Bis-GMA, TEGDMA, and camphorquinone were used as the main material, cross-linking agent, and photoinitiator, respectively. In addition, 2-isocyanatoethyl methacrylate was used as an additive for high strength, while the 3-hydroxypyridine was used as an additive for antibacterial activity. Photopolymerization was also carried out at a 440-480 nm wavelength and at about $1000mW/cm^2$ intensity for about 40 seconds. The breaking strength measurement of the samples showed that the breaking strength increased along with increasing the addition ratio of IEM, while it took less time until the polymerization was complete, thereby suggesting that the degree of polymerization has the tendency to increase. And also, compared to the size of the clear zone formed by ampicillin, the 3-hydroxypyridine group exhibited antimicrobial activity induced by ampicillin. The results of this study suggest that the use of 2-isocyanatoethyl methacrylate as an additive for high strength and 3-hydroxypyridine as an additive for improved antibacterial activity would improve the usability of the fabricated polymer as a dental resin cement material with high functionality.

• Journal of the Korean Chemical Society
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• v.62 no.2
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• pp.113-117
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• 2018

The basic hydrogel lens with addition of N,N-dimethylacrylamide (DMA) and N-methyl-N-vinylacetamide (NMV) were manufactured. The optical and physical characteristics of ophthalmic lens were evaluated by measuring water content, oxygen permeability (Dk), refractive index and optical transmittance. The water content & oxygen permeability (Dk) of sample containing Ref., DMA group and NMV group was in the average of 34.48%, 35.54~49.19% & $13.003{\sim}18.468{\times}10^{-11}(cm^2/sec)$($mlO_2/ml{\times}mmHg$) and 36.28~44.95% & $12.270{\sim}16.883{\times}10^{-11}(cm^2/sec)$ ($mlO_2/ml{\times}mmHg$), respectively. And also, refractive index of the sample containing Ref., DMA group and NMV group was in the average of 1.4350, 1.4330~1.4131 and 1.4335~1.4195, respectively. Standard hydrogel monomer containing DMA and NMV was expected to be used usefully as a material for fabricating hydrophilic functional ophthalmic lens.

• Journal of the Korean Chemical Society
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• v.60 no.4
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• pp.261-266
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• 2016

The major physical characteristics of macromolecules used in silicone hydrogel ophthalmic lenses include optical transmittance, oxygen permeability, water content, and refractive index. For the preparation of highly functional silicone hydrogel lens materials, two silicone monomers were used in the presence of 2-hydroxyethyl methacrylate (HEMA) and hydroxypropyl methacrylate (HPMA). The samples containing HEMA and HPMA had oxygen transmissibility (Dk) values in the range of 73.38–50.98 × 10^-11 (cm²/s) (mLO₂/mL×mmHg) and 71.94–42.80 × 10^-11 (cm²/s) (mLO₂/mL×mmHg), respectively. Furthermore, the water contents of samples containing HEMA and HPMA were in the range of 32.73–34.67% and 31.94–33.74%, respectively, and the refractive indices were in the range of 1.4348–1.4364 and 1.4385–1.4407, respectively. Thus, silicone monomers containing HEMA and HPMA are expected to be useful for fabricating high-oxygen-permeability silicon hydrogel ophthalmic lenses.