• Journal of the Society of Cosmetic Scientists of Korea
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• v.38 no.4
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• pp.263-270
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• 2012

Ascorbic acid (Vitamin C) becomes unstable in the aqueous phase by oxygen, light and alkali, etc. The properties are limited in application to cosmetics. The most important factor that determines the destabilization of ascorbic acid in the aqueous phase was tried to understand considering its molecular deformation and degradation. In this study, we changed the polyols and emulsification technique for the stability of ascorbic acid. Then we observed the color and concentration change of ascorbic acid at room temperature and high temperature ($42^{\circ}C$) for 6 weeks and identified the stability using HPLC regularly. As a result, we found that glycerin was the most appropriate polyol for stability of the ascorbic acid. Also the technique of nonaqueous emulsification stabilized ascorbic acid than P/S emulsification. Also, P/S emulsification, glycerin was more stable than propylene glycol. By the results we suggest that ascorbic acid could be stabilized by nonaqueous emulsification method and this data could be applied to stabilization methods for cosmetic products.

• KSBB Journal
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• v.10 no.2
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• pp.204-211
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• 1995

A target-sensitive liposome was prepared by using a dioleoyl-phosphatidylethanolamine(DOPE) and a palmitic acid coupled antibody(p-IgG). For the preparation of stable PE-liposomes, the key factors such as antibody modification method with palmitic acrid, molar ratio of p-IgG to lipid and the amount of various additives, were examined. The optimum molar ratio of p-IgG to lipid was found to be $2.5{\times}10^{-4}$ and the final concentration of deoxycholate for the stable liposome formation was about 0.09%. Two kinds of target-sensitive liposomes, containing polyclonal anti-SRBC(Sheep Red Blood Cell)-antibody and monoclonal anti-${\beta}$-HCG(Human Chorionic Gonadotropin)-antibody, were successfully prepared. The destabilization of liposomes was examined by measuring the release of calcein entrapped in the liposome vesicles. Calcein was released only when the liposomes were contacted with the specific target cells. The calcein release with non-specific target cells was negligible. From this result, it is clear that p-IgG is indispensible for the maintenance of stable PE-liposome and the calcein release is mainly due to the specific interactions between the liposomes containing antibody and the target cells containing antigen.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.5
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• pp.423-430
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• 2014

Noise and vibration, which occur in a pipe, are usually caused by the interaction between the turbulent flow and nearby wall. Although it can be estimated by a simple case of expanded pipes having complex turbulent flow, the radiated noise is highly dependent upon the size, shape, and thickness of the given model. In addition, the radiated noise propagates and has serious interference and destabilization effects on the surrounding systems, which can lead to fatigue fracture and failure. This study took advantage of the variety of commercial programs, such as FLUENT (flow solver), NASTRAN (dynamic motion solver of complex structures) and VIRTUAL LAB (radiated noise solver) based on the boundary element method (BEM), to understand the underlying physics of flow noise. The expanded pipe has separation and a high pressure drop because of the abrupt change in the cross-section. Based on the radiated noise calculations, the noise level was reduced to around 20 dB in the range of 100-500 Hz.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.72-72
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• 2017

We found a new stay-green mutant from 'Pyeongwon' which is an early-maturing rice variety in Korea. The mutant showed green leaves after grain ripening period and it maintained higher SPAD value than wild type rice plant and original variety 'Pyeongwon'. The stay-green trait in rice, three genes have been identified up to date. The non-yellow coloring1 (NYC1) gene encodes a chloroplast-localized short-chain dehydrogenase/reductase (SDR) with three transmembrane domains. The non-yellow coloring3 (NYC3) gene encodes a plastid-localizing alpha/beta hydrolase-fold family protein with an esterase/lipase motif. The Sgr gene encodes a novel chloroplast protein and regulates the destabilization of the light-harvesting chlorophyll binding protein (LHCP) complexes of the thylakoid membranes, which is a prerequisite event for the degradation of chlorophylls and LHCPs during senescence. After sequencing the PCR products, we found a single nucleotide variation($A{\rightarrow}T$) in the NYC1 gene, which changes the amino acid lysine to methionine. The NYC1 gene encodes a short-chain dehydrogenase/reductase(SDR) protein. And we confirmed the co-segregation between SNP and stay-green trait from genotyping the progenies of the mutant.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.3
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• pp.226-232
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• 2000

Corrosion mechanisms by molten steel and slag were investigated in the zirconia/graphite composite as a material of submerged entry nozzle (SEN) using for producing high quality steel. Most of corrosions were started by the dissolution of zirconia particles into molten steel and oxidation of graphite, but subsequently three modes of corrosion were observed. Firstly, the penetration of slag into zirconia matrix was induced to the diffusion of stabilizing agent outward cubic zirconia grains, and the destabilization of cubic to fine monoclinic zirconia particles, which is enhanced to the decomposition and dissolution of them into slag. Secondly, molten slag penetrates into large cubic zirconia particles along grain boundary and decomposed them to fine cubic grains, which is also enhanced to the dissolution of zirconia grains into slag. Lastly, reaction between carbon and cubic zirconia was formed porous ZrC and enhanced the dissolution of it into slag.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.2
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• pp.617-622
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• 2014

Voacanga globosa (Blanco), a plant endemic to the Philippines, is traditionally used especially by indigenous people of Bataan in the treatment of ulcers, wounds and tumorous growths. This study aimed to provide scientific evidence to therapeutic properties by determining cytotoxic and pro-apoptotic activity of HPLC fractions from leaves on HCT116 human colon carcinoma and A549 human lung carcinoma cell lines. Ethanolic extraction was performed on V globosa leaves followed by hexane and ethyl acetate partitioning. Silica gel column chromatography and high performance liquid chromatography (HPLC) produced MP1, MP2 and MP3 fractions. Cytotoxic activity of the fractions was determined through MTT assay against the cancer cell lines HCT116 and A549 and the non-cancer AA8 Chinese hamster ovarian cell line. Pro-apoptotic activities of the most active fractions were further assessed through DAPI staining, TUNEL assay and JC-1 mitochondrial membrane potential assay with HCT116 cells. While the MPI fraction exerted no significant activity against all cell lines tested, MP2 and MP3 fractions demonstrated high toxicity against HCT116 and A549 cells. The MP3 fraction induced formation of apoptotic bodies, condensed DNA and other morphological changes consistent with apoptosis of HCT116 cells and TUNEL assay showed significant increase in DNA fragmentation over time. In these cells, the MP3 fraction also induced mitochondrial membrane destabilization, which is generally associated with the beginning of apoptosis. Phytochemical analysis demonstrated the presence only of saponins and terpenoids in the MP3 fraction. The results indicate that the MP3 fraction exerts cytotoxic activity on HCT116 cells via induction of apoptosis triggered by loss of mitochondrial membrane potential crucial for cell survival.

• Preventive Nutrition and Food Science
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• v.5 no.4
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• pp.184-188
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• 2000

HMG-CoA reductase is th rate-limiting enzyme of cholesterol biosynthesis. As intracellular levels of cholesterol should be regulated elaborately in response to external stimuli an internal needs, the expression of the HMG-CoA reductase gene is regulated intricately at several different levels from transcription to post-translational modification. In this study, we investigated the regulatory mechanism of HMG-CoA reductase gene expression at the post-transcriptional/pre-translational levels in a baby hamster kidney cell line, C100. when 25-hydroxycholesterol was added to cells cultured in medium containing 5% delipidized fetal bovine serum and 25$\mu$M lovastatin, the levels of HMG-CoA reductase mRNA decreased rapidly, which seemed to be due to the increased degradation of reductase mRNA. These suppressive effects of 25-hydroxycholesterol on MG-CoA reductase mRNA levels were blocked by a translation inhibitor, cycloheximide. Similarly, actinomycin D and 5,6-dichloro-1-$\beta$-D-ribofuranosylbenzimidazole, transcription inhibitors, blocked the 25-hydroxycholesterol-mediated degradation of HMG-CoA reductase mRNA. These results indicate that new protein/RNA synthesis is required for the degradation of HMG-CoA reductase mRNA. In addition, data from the transfection experiments shows that cis-acting determinants, regulating the stability of reductase mRNA, were scattered in the sequence corresponding to 1766-4313 based on the sequence of Syrian hamster HMG-CoA reductase cDNA. Our data suggests that sterol-mediated destabilization of reductase mRNA might be one of the important regulatory mechanism of HMG-CoA reductase gene expression.

• Journal of Korean Society on Water Environment
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• v.20 no.6
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• pp.625-630
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• 2004

Granular media filtration is used almost universally as the last particle removal process in conventional water treatment plants. Therefore, superb particle removal efficiency is needed during this process to ensure a high quality of drinking water. However, every particle can not be removed during granular media filtration. Besides the pattern of particle attachment is different depending on physicochemical aspects of particles and suspension. Filtration experiments were performed in a laboratory-scale filter using spherical glass beads with a diameter of 0.55 mm as collectors. A single type of particle suspension (Min-U-Sil 5) and alum coagulation was used to destabilize particles. The operating conditions were similar to those of standard media filtration practice: a filtration velocity of 5 m/h. More favorable particles, i.e., particles with smaller surface charge, were well attached to the collectors especially during the early stage of filtration when zeta potential of particles and collectors are both negative. This selective attachment of the lower charged particles caused the zeta potential distribution (ZPD) of the effluent to move to a more negative range. On the other hand, the ZPDs of the effluent moved from more positive to less positive when the surface charge of particles was positive and this result was thought to be caused by ion transfer between particles and collectors.

• Journal of Korean Society on Water Environment
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• v.22 no.5
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• pp.958-967
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• 2006

The overall objective of this research was to find out the role of rapid mixing conditions in the species of hydrolyzed Al(III) formed by Al(III) coagulants and to evaluate the distribution of hydrolyzed Al(III) species by coagulant dose and coagulation pH. When an Al(III) salt was added to water, monomers, polymers and solid precipitates may form. Different Al(III) coagulants (alum and PSOM) show to have different Al(III) species distribution over a rapid mixing condition. During the rapid mixing period, for alum, formation of dissolved AI(III) (monomer and polymer) increases, but for PSOM, precipitates of $Al(OH)_{3(S)}$ increases rapidly. During the rapid mixing period, for high coagulant dose, Al-ferron reaction increases rapidly. The kinetic constants, Ka and Kb, derived from AI-ferron reaction. The kinetic constants followed very well the defined tendencies for coagulation condition. For pure water, when the rapid mixing time increased, the kinetic constants, Ka and Kb showed lower values. Also, for raw water, when the rapid mixing time increased, the kinetic constants, Ka and Kb showed lower values. At A/D(Adsorption and Destabilization) and sweep condition, both $Al(OH)_{3(S)}$ and dissolved Al(III) (monomer and polymer) exist, concurrent reactions by both mechanism appear to cause simultaneous precipitation.

• Journal of Pharmaceutical Investigation
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• v.39 no.4
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• pp.249-255
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• 2009

The main object of this study was to prepare of w/o emulsion including glyceryl monooleate(GMO) and to evaluate its stability by using the recently developed $Turbiscan^{(R)}LAB$. GMO is the polar oily surfactant with the low HLB value, and it forms the gel phase of cubic structures after dissolves in aqueous media. Phosphate buffer solution (PBS) of pH 7.4 was prepared as the water phase and Marcol 52(mineral oil) was used as the oil phase in this study. GMO was used as the surfactant of W/O emulsion. W/O emulsion using GMO alone as a surfactant was very unstable. But the emulsion using both GMO and poloxamer 407 was more stable. The stability of W/O emulsions was evaluated after centrifuging the emulsions. But it was difficult with naked eye because an opaque and concentrated system like W/O emulsion was very turbid. So $Turbiscan^{(R)}LAB$ was used to detect the destabilization phenomena in non-diluted emulsion. As a result, the W/O emulsion using the proper amounts of GMO and poloxamer 407 was more stable among them using GMO of various amounts. But it seems that the other element for the stability of W/O emulsion including GMO was required. Furthermore, the $Turbiscan^{(R)}LAB$ was a very efficient analyzer for evaluating the physical stability of emulsion.