• Journal of the Korea Institute of Building Construction
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• v.11 no.6
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• pp.587-596
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• 2011

Ultra rapid-hardening cement is widely used for latex-modified mortar and concrete as repair and finishing material during urgent work. The purpose of this study is to evaluate the improvements in strength made to SBR cement mortars by the adding of various admixtures and by the use of different curing methods. SBR cement mortar was prepared with various polymer-cement ratios, curing conditions and admixture contents, and tested for flow, flexural and compressive strengths. From the test results, it was determined that the flow of SBR cement mortar increased with an increase in the polymer-cement ratio, and the water reducing ratio also increased. The strength of cement mortar is improved by using SBR emulsion, and is strengthened by adding metakaoline. The strength of SBR cement mortar cured in standard conditions was increased with an increase in the polymer-cement ratio, and attained the maximum strengths at polymer-cement ratios of 15 % and 10 %, respectively. The maximum strengths of SBR cement mortar are about 1.8 and 1.3 times the strengths of plain mortar, respectively. In this study, it is confirmed that the polymer-cement ratio and curing method are important factors for improving the strengths of rapid-hardening SBR cement mortar.

• Korean Chemical Engineering Research
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• v.40 no.6
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• pp.669-675
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• 2002

The alkenylation of o-xylene with 1,3-butadiene to make OTP(ortho-tolyl Pentene) was carried out over liquid phase NaK alloy, Na metal and the metallic sodium dispersed on the specific support such as NaX and $Al_2O_3$. Liquid phase NaK alloy showed the improved conversion and selectivity when they were pretreated by ultrasound to increase the dispersion. For the case of metallic sodium, the induction period for the formation of homogeneous metal sodium solution with high dispersion was needed before the reaction. In the case of metallic sodium dispersed on support, more than 80 % conversion could be obtained without induction period regardless of supports used. But 85 % of the metallic sodium was resolved into the reaction mixture after reaction for 7 hours. The amount of byproducts, oligomers, produced from OTP and 1,3-butadiene increased with the amount of 1,3-butadiene introduced and the selectivity to OTP was in inversely proportional to the conversion.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.3
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• pp.189-199
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• 2015

In this study, we have investigated the stability of sunscreens based on the solubility of organic UV absorbers in the oil and sun protection efficacy of the products composed of a combination of organic UV absorbers to develop more stable and efficient sunscreen products. Results showed that the solubility of the organic UV absorber and stability were varied depending on the type, storage conditions and concentration of oil. It was also observed from the products in the emulsion type. Various UV absorbances were determined to the products composed of the combination of organic UV absorbers. In some combinations, a synergistic effect was observed to make an increase in absorbance compared to a single component. In other cases, specific synergistic effect was displayed only when combined with the particular component. In addition, the storage condition also affected the sunscreen efficacy. In conclusion, this study confirmed that there are various factors which could affect the UV-blocking efficiency of sunscreen products.

• Food Science and Preservation
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• v.7 no.3
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• pp.331-336
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• 2000

The phenolic compounds of Korean sweet potatoes, Mokpo 18 and Yulmi, were extracted by using 70%-methanol and the extracts(ME) were fractionated and obtained three fractions such as free phenolic acid(FPAF), soluble phenolic acid ester(SPAF) and insoluble bound phenolic acid(BPAF) fractions. The antioxidative activities(AA) was represented as the peroxide values(POVs). The POVs were calculated by measuring the oxidation of linoleic acid and lard emulsions at $60^{\circ}C$. AA of FPAF has shown the most effective. AA of FPAF were more effective than those of ME in both Yulmi and Mokpo 18. AA of the ME of Mokpo 18 were more effective than those of Yulmi, however, those of FPAF in Ulmi were more effective than in Mokpo 18. The POVs of ME and FPAF of the peel part in both sweet potatoes were more effective than those of peeled part. The qualitative and quantitative analysis of the phenolic compounds in both sweet-potatoes were performed by using high performance liquid chromatography(HPLC) and the major phenolic compounds were identified as chlorogenic acid and caffeic acid. The contents of caffeic acid were 0.684mg/g in the peel part and 0.028mg/g in the peeled part of Yulmi and 0.472mg/g in the peel part and 0.046mg/g in the peeled part of Mokpo 18 and those of chlorogenic acid was 0.674mg/g, 0.926mg/g, and 0.012mg/g, respectively. In comparative test of antioxidative activities between a standard chlorogenic acid and caffeic acid, AA of caffeic acid were more effective than those of chlorogenic acid.

• Polymer(Korea)
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• v.38 no.5
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• pp.656-663
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• 2014

Atorvastatin calcium-loaded polyoxalate (POX) microspheres were prepared by an emulsion solvent-evaporation/ extraction method of oil-in-oil-in-water ($O_1/O_2/W$) for sustained release. We investigated the release behavior according to initial drug ratio, molecular weight ($M_w$) and concentration of POX and concentration of emulsifier. The microsphere was characterized on the surface, the cross-section morphology and the behavior of atorvastatin calcium release for 10 days by scanning electron microscopy (SEM) and high performance liquid chromatography (HPLC). The analysis of crystallization was analyzed to use X-ray diffraction (XRD), differential scanning calorimeter (DSC) and Fourier transform infrared (FTIR). These results showed that the release behaviors can be controlled by preparation conditions.

• Food Science of Animal Resources
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• v.34 no.3
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• pp.378-386
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• 2014

This study was conducted to determine the effects of red and green glasswort on the physicochemical and textural properties of reduced-salt cooked sausages. The control was formulated with 1.5% NaCl; then, three reduced-salt treatments were prepared, with 0.75% NaCl (RS), 0.75% NaCl+1.0% red glasswort (RSR) and 0.75% NaCl+1.0% green glasswort (RSG), respectively. The addition of glasswort within the added amount of 1% had no influence on the pH value of the reduced-salt cooked sausages, regardless of the glasswort type. In terms of color, RSG treatment conveyed a higher hue angle value than the RSR treatment (p<0.05). Increases in the protein solubility (total and myofibrillar proteins) and apparent viscosity of reduced-salt meat batter that were due to the addition of glasswort were observed; however, there were no differences according to the type of glasswort (p>0.05). Furthermore, the addition of glasswort, regardless of its type, resulted in decreased cooking loss, and increased emulsion stability. As a result, reduced-salt cooked sausages formulated with either red or green glasswort demonstrated similar textural properties to those of the control. In conclusion, the type of glasswort within an added amount of 1% had no influence on the physicochemical and textural properties of reduced-salt cooked sausages, except for the color characteristics. In terms of color alteration by the addition of glasswort, the red glasswort, which in comparison with the green glasswort could minimize the color changes of reduced-salt cooked sausages, might be an effective source for manufacturing meat products.

• Korean Journal of Food Science and Technology
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• v.29 no.5
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• pp.1045-1051
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• 1997

Three kinds of model melanoidins adjusted to have the same brown color intensity were made from glucose-glycine, glucose-lysine, xylose-arginine and their antioxidative properties were determined. The antioxidative activities of these model melanoidins in linoleic acid emulsion system were determined by ferric thiocyanate method, conjugated diene contents, peroxide value and electron donating ability by DPPH. Xylose-arginine melanoidin showed the strongest antioxidative activity and electron donating ability. The antioxidative effect of melanoidin could be reliably predicted by determining peroxide value and DPPH method. Each melanoidin was separated on Sephadex G-50 column, and brown color intensity, reducing power, ninhydrin positive reaction and antioxidative activity of each fraction were determined. The antioxidative activities of melanoidin fractions showed strong correlation with their brown color intensity and especially to their reducing power. In spite of same brown color intensity, there is no big differences between these model melanoidins, thus xylose-arginine showing strongest antioxidative activity followed by glucose-lysine and glucose-glycine melanoidin. Xylose-arginine melanoidin also showed the strongest electron donating activity and broad range of reducing power when fractionated on Sephadex G-50, which was different tendency from the other model melanoidin.

• Korean Journal of Food Science and Technology
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• v.27 no.3
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• pp.375-379
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• 1995

Contents of ${\beta}-carotene$ and vitamin C in the vegetable(Angelica keiskei) juice were measured as a function of storing temperature$(-18^{\circ}C{\sim}35^{\circ}C)$ and period$(6{\sim}72\;hours)$. Content of ${\beta}-carotene$ was highest in the fresh juice and the degree of destruction of the ${\beta}-carotene$ was significantly increased as the storage temperature increased. Vitamin C in the juice stored at $4^{\circ}C$ decreased less than that of ${\beta}-carotene$. There was no significant difference in fatty acid compositions among in the fresh, freeze-dried juice and juice stored for 72 hours. Antioxidative activities of components extracted from the juice(fresh and stored for 24 hours) followed by incubating for 1 day were higher than that of ${\alpha}-tocopherol$ and then significantly decreased as incubation prolonged.

• Korean Journal of Food Science and Technology
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• v.28 no.3
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• pp.506-513
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• 1996

Soybean hull was microparticulated at cut-off wheel speed of 9,000 rpm and air-classified into fine and coarse fraction at air classifying wheel speeds (ACWS) of 10.000, 15,000 and 20,000 rpm. respectively. Proximate analysis of the coarse and fine fractions of the microparticulated/air-classified soybean hull showed that ash, protein and lipid were enriched in the coarse fractions and carbohydrates in the fine fraction. Dietary fiber were enriched in coarse fractions and dietary fiber and dietary fiber content increased with decreasing ACWS. Mean particle size of fine fractions ranged from $3.1{\mu}m\;to\;5.5{\mu}m$ that of coarse fractions ranged from $9.9{\mu}m\;to\;20.0{\mu}m$ and both increased with decreasing ACWS. The particles were mostly oval-shaped regardless of the fractions. Generally the fraction of low ACWS showed higher viscosity. In water holding capacity, oil absorption and emulsion capacity, there was significant difference between coarse and fine fractions while there was no significant difference as a function of different ACWS. Oil absorption of flying batter was decreased significantly in the fraction of ACWS 15,000. when cakes and cooking were prepared partially substituted with soybean hull fraction, there was no significant changes on their physical and sensory properties up to 10% substitution.

• Journal of Pharmaceutical Investigation
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• v.38 no.6
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• pp.373-380
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• 2008

In order to develop optimal formulation and iontophoresis condition for the transdermal delivery of levodopa, we have evaluated the effect of two permeation enhancers, ethanol and oleic acid in microemulsion, on transdermal delivery of levodopa. In vitro flux studies were performed at $33^{\circ}C$, using side-by-side diffusion cell and full thickness hairless mouse skin. Current density applied was $0.4\;mA/cm^2$ and current was off after 6 hours application. Levodopa was analysed by HPLC at 280 nm. The o/w microemulsions of oleic acid in buffer solution (pH 2.5 & 4.5) were prepared using oleic acid, Tween 80 and ethanol. The existence of microemulsion regions were investigated in pseudo-ternary phase diagrams. Contrary to our expectation, cumulative amount of levodopa transported from microemulsion (pH 2.5) for 10 hours was similar to that from aqueous solution in all delivery methods (passive, anodal and cathodal). When pH of the micro-emulsion was pH 4.5, cumulative amount of levodopa transported for 10 hours increased about 40% (anodal) to 50% (cathodal), when compared to that from aqueous solution. Flux from pH 4.5 microemulsion showed higher value than that from pH 2.5 in all delivery methods. These results seem to indicate that electroosmosis plays more dominant role than electrorepulsion in the flux of levodopa at pH 2.5. The effect of ethanol on iontophoretic flux was studied using pH 2.5 phosphate buffer solution containing 3% or 5% (v/v) ethanol. Flux enhancement was observed in passive and anodal delivery as the concentration of the ethanol increased. Without ethanol, cathodal delivery showed higher flux than anodal delivery. Anodal delivery increased the cumulative amount of levodopa transported 1.6 fold by 5% ethanol after 10 hours. However, in cathodal delivery, no flux enhancement of levodopa was observed during current application and only marginal increase in cumulative amount transported after 10 hours was observed by 5% ethanol. These results seem to be related to the decrease in dielectric constant of the medium and the lipid extraction of the ethanol, which decrease the electroosmotic flow, and thus decrease the flux. Overall, the results provide important insights into the role of electroosmosis and electrorepulsion in the transport of levodopa through skin, and provide some useful informations for optimal formulation for levodopa.