• Journal of Korean Society of Environmental Engineers
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• v.37 no.6
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• pp.357-362
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• 2015

A novel $TiO_2$-Coconut Shell Powder Composite (TCSPS), prepared by the controlled sol-gel method with subsequent heat treatment, was evaluated as an innovative photocatalytic absorbent for the removal of methylene blue. Optimal preparation conditions of TCSPC were obtained by a response surface methodology and a central composite design model. As compared with the results obtained from one-factor-at-a-time experiments, the values were approximated to the nearest condition of these values and the following experimental parameters were set as the optimum : $600^{\circ}C$ calcination temperature and 20 g of coconut shell powder loading amount.

• Nuclear Engineering and Technology
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• v.12 no.1
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• pp.1-8
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• 1980

The grafting studies were concentrated on working out the methodology for radiation of flame retardants to polyester/cotton (65/35) blend fabric. The Fyrol 76 was used as a flame retardant in develping methodology for localizing flame retardants on the surface of the blend fabric. By judicious control of the swelling conditions, time_of contact with the monomer, and dose rate, locating the graft in the fiber became possible. The yield of the graft polymerization was depended upon the total dose and the preswelling conditions. Oxygen Index was used to evaluate the effect of the location of Fyrol 76 and other flame retardants within the surface upon the flame retardance efficiencies. To get a better flame retardance efficiency by :the localized grafting of Fyrol 76 to polyester/cotton blend fabric, a technique of one step processing at room temperature was developed substituting the ordinary two-step processing at high temperature.

• Membrane Journal
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• v.11 no.2
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• pp.83-88
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• 2001

A methodology for enhancing the bond strength of a coating layer with a support has been established in preparing low-pressure reverse osmosis mO) hollow fiber which would experience shear badly in flowing feed un it. Prior to coating process, the support membrane, ultrafiltratiun polysulfone(PS) hollow fibers was pretreated with a reaction solution containing glutaraldehyde (GAl which has a good affinity to the suppurt membrane material as well as a reactivity to some of the cunstituents of cuating layer subsequently formed on the support by interfacial polymerization. Therefore, the reactant GA distributed unifonnly over the support layer through the pretreatment could provide a strong adhesive bond between the coating layer and the support, sticking fast to the support membrane through physical bond and, at the same time, connecting its functional group with the coating laycr by chemical bonding. Due to the strong adhesive bond, the resulting hollow fiber membrane showed an excellent long-tcnn stability in pcnneation.

• The Journal of Advanced Prosthodontics
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• v.5 no.4
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• pp.464-470
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• 2013

PURPOSE. The aim of this Fourier transform infrared (FTIR) spectroscopic study was to measure the degree of conversion (DC) of dual-cured resin cements light-irradiated through zirconia ceramic disks with different thicknesses using various light-curing methods. MATERIALS AND METHODS. Zirconia ceramic disks (KT12) with three different thicknesses (1.0, 2.0, and 4.0 mm) were prepared. The light transmittance of the disks was measured using ultraviolet visible near-infrared spectroscopy. Four different light-curing protocols were used by combining two curing light modes (Elipar TriLight (standard mode) and bluephase G2 (high power mode)) with light-exposure times of 40 and 120 seconds. The DCs of the two dual-cured resin cements (Duo-Link and Panavia F2.0) light-irradiated through the disks was analyzed at three time intervals (3, 7, and 10 minutes) by FTIR spectroscopy. The data was analyzed using repeated measures ANOVA (${\alpha}$=.05).Two-way ANOVA and Tukey post hoc test were used to analyze the 10 minute DC results. RESULTS. The 1.0 mm thick disk exhibited low light transmittance (<25%), and the transmittance decreased considerably with increasing disk thickness. All groups exhibited significantly higher 10 minute DC values than the 3 or 7 minute values (P<.05), but some exceptions were observed in Duo-Link. Two-way ANOVA revealed that the influence of the zirconia disk thickness on the 10 minute DC was dependent on the light-curing methods (P<.001). This finding was still valid even at 4.0 mm thickness, where substantial light attenuation took place. CONCLUSION. The curing of the dual-cured resin cements was affected significantly by the light-curing technique, even though the additional chemical polymerization mechanism worked effectively.

• Korean Journal of Food Science and Technology
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• v.24 no.6
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• pp.568-573
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• 1992

Molecular structural properties of Japonica and Tongil type waxy rice starches were compared. The general properties including water-binding capacity, swelling power at $80^{\circ}C$, intrinsic viscosity, leach loss at $98^{\circ}C$ and ${\beta}-amylolysis$ limit were similar but the chain length was slightly different between the two starches. Similar elution profiles on Sephadex G-50 were obtained when the starches were treated with ${\beta}-amylase$. The pullulanase treated starches however showed different elution patterns each other. The ${\beta}-amylolysis$ of acid-treated (2 days) starches linearly increased as hydrolysis time prolonged. When the acid-treated starches were hydrolyzed with ${\beta}-amylase$ or pullulanase, the elution profiles on Sepharose CL-2B were considerably different from those of native starches.

• Journal of Sericultural and Entomological Science
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• v.41 no.1
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• pp.48-53
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• 1999

The study was carried out to investigate the effects of hydrolysis conditions such as treatment times and concentrations on the solubility of insoluble sericin using the hydrochloric acid solution. When insoluble sericin was hydrolyzed by HCl solution, the solubility was increased with the higher treatment concentration. As the results of electrophoresis of sericin powder obtained by the HCl treatment, a distinguishable band was not confirmed. Average degree of polymerizations(A.D.P.) of sericin hydrolyzed by HCl solution were about 4.2~5.9 and average molecular weights(M.W.) were about 470~670. The longer hydrolysis time reduced the whiteness of sericin powder. As the results of amino acid analysis, the amino acid compositions of the sericin powder from HCl treatment were sililar to that of insoluble sericin, but Tyr. and Arg. were not detected in the powder obtained by HCl treatment. In DSC analysis, thermal deformation and pyrolysis peak located at near 220$^{\circ}C$ and 330$^{\circ}C$.

• Archives of Craniofacial Surgery
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• v.13 no.2
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• pp.125-129
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• 2012

Purpose: Methylmethacrylate is the most commonly used alloplastic material in cranioplasty. However during the polymerization of methylmethacrylate, a significant exothermic reaction takes place. This reaction may result in thermal injury to the brain tissue and other soft tissues. Also it is difficult to make three-dimensional methylmethacrylate implant that is perfectly matched to the defect during the operation time. We report on the molding technique of methylmethacrylate implant using plaster mold and the rapid prototyping model in cranioplasty. Methods: A 44-year-old male was referred to the department for severe frontal hollowness. He was involved in an automobile accident resulting in large frontal bone defect with irregular margin. The preformed patient-specific methylmethacrylate implant was made using plaster mold and the rapid prototyping model before the operative day. The methylmethacrylate implant was placed in the frontal defect and rigidly fixed with miniplates and screws on the operative day. Results: The operation was performed in an hour. In the 6 months follow-up period, there were no complications. Patient was satisfied with the results of cranioplasty. Conclusion: Safe cranioplasty was performed with the preformed patient-specific methylmethacrylate implant using plaster mold and the rapid prototyping model. The result of this method was satisfactory, aesthetically and functionally.

• KSBB Journal
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• v.17 no.2
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• pp.137-141
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• 2002

Levan oligosaccoharides and low molecular weight levin were produced from levin by acid hydrolysis and following column chromatography. Levan hydrolysis was progressed proportionally as increased incubation time. In terms of levan hydrolysis reaction, no differences were found from the sources of levan. Optimum hydrolysis conditions for the formation of levan oligosaccharides were, 0.38 M H$_2$S0$_4$; and incubation at 95$\^{C}$ for 4 min. The purified products were determined as the mixture of oligosaccharides (degree of polymerization (DP) of 3-6), Two of lactic acid-producing bacteria, Lactobacillus plantarum KCTC 3104 and Pediococcus pentosaceus KCTC 3507, were studied in vitro for their ability to metabolize levin oligosaccharides. Apparently, the growth of both cells were increased by levin oligosaccharide diet, compared with those of levan diets, suggesting that levan oligosaccharides may be beneficial in selectively growth of lactic acid-producing bacteria.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.5
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• pp.2335-2340
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• 2014

Paclitaxel is hydrophobic in nature and is recognized as a highly toxic anticancer drug, showing adverse effects in normal body sites. In this study, we developed a polymeric nano drug carrier for safe delivery of the paclitaxel to the cancer that releases the drug in a sustained manner and reduces side effects. N-isopropylacrylamide/vinyl pyrrolidone (NIPAAm/VP) nanoparticles were synthesized by radical polymerization. Physicochemical characterization of the polymeric nanoparticles was conducted using dynamic light scattering, transmission electron microscopy, scanning electron microscopy and nuclear magnetic resonance, which confirmedpolymerization of formulated nanoparticles. Drug release was assessed using a spectrophotometer and cell viability assays were carried out on the MCF-7 breast cancer and B16F0 skin cancer cell lines. NIPAAm/VP nanoparticles demonstrated a size distribution in the 65-108 nm range and surface charge measured -15.4 mV. SEM showed the nanoparticles to be spherical in shape with a slow drug release of ~70% in PBS at $38^{\circ}C$ over 96 h. Drug loaded nanoparticles were associated with increased viability of MCF-7 and B16F0 cells in comparison to free paclitaxel. Nano loaded paclitaxel shows high therapeutic efficiency by sustained release action for the longer period of time, i increasing its efficacy and biocompatibility for human cancer therapy. Therefore, paclitaxel loaded (NIPAAm/VP) nanoparticles may provide opportunities to expand delivery of the drug for clinical selection.

• Polymer(Korea)
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• v.24 no.1
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• pp.29-37
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• 2000

Polyaniline (PANi)/Poly(ethylene of oxide) (PEO) in-situ blends were prepared by inducing phase separation through solvent evaporation after casting from solutions containing aniline monomer, oxidant (initiator), dopant and PEO in methanol/water mixed solvent. It was observed that the electrical conductivity first increases rapidly as PANi amount in the PANi/PEO blend increases and then slowly increases as the weight percentages of polyaniline become above 11 wt% in the blend. We also noted that the morphology of PANi/PEO blends changes when the holding time in a stirrer at constant temperature is varied and eventually affects the electrical conductivity. As the length of alkyl group in dopants increases, the electrical conductivity of doped blends increases. The PANi/PEO blend prepared with a high molecular weight of PEO yields higher electrical conductivity.