• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3223-3226
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• 2013

Spherical phospholipid-bilayers, vesicles, were prepared using the layer-by-layer double emulsion technique, which allows the bilayer to be formed asymmetrically. On the outer layer of the vesicles, the phospholipase D (PLD) reacted to convert phosphatidylcholine (PC) to phosphatidic acid (PA). The reaction induced the curvature change of the vesicles, which eventually led to rupture. The response time from the time of PLD injection to the time of rupture was measured against different vesicle curvatures and the outer layer phase, using the fluorescence intensity change of a pH-sensitive dye encapsulated within the vesicles. The effect of the vesicle curvature on the response was observed to be more significantly dramatic at the solid phase, compared to the liquid phase. Furthermore, in the solid phase, the response time was faster for 80 and 155 nm vesicles and, slower for 605 nm vesicles than similarly sized vesicles in the liquid phase vesicles. This difference in the response time was thought to result from the configuration determined by the phase difference and the PLD behavior.

• Journal of Pharmaceutical Investigation
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• v.41 no.3
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• pp.185-190
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• 2011

The purpose of this study was to evaluate the phagocytic uptake of surface modified PLGA microspheres containing ovalbumin (OVA) into dendritic cell. In order to find the most suitable formulation for targeted delivery to antigen presenting cells (APC), OVA was encapsulated by a double emulsion solvent evaporation method with three PLGA microspheres (PLGA 50:50, PLGA 75:25 and PLGA 85:15) and two surface modified microspheres by chitosan and sodium dodecyl sulfate (SDS). Physicochemical properties were evaluated in terms of size, zeta potential, encapsulation efficiency, different scanning calorimeter (DSC), x-ray diffraction, morphology, and OVA release test from microspheres. Phagocytic activity was estimated using dendritic cells and analyzed by fluorescence activated cell sorter (FACS). The result showed that zeta potential of PLGA particles was changed to positive by the chitosan modification. The release profile of chitosan modified PLGA microspheres exhibited sustained release after initial burst. The chitosan modified microspheres had higher phagocytic uptake than the other microspheres. Such physicochemical properties and phagocytic uptake studies lead us to conclude that chitosan modified microspheres is more suitable formulation for the targeted delivery of antigens to APC compared with the other microspheres.

• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.261-265
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• 1997

To know the availability of double fractionated palm olein (DFPL) for vegetable oil in commercial mayonnaise preparation, oxidative stability and stability to cold test of DFPL, soybean oil and blended oils (blended soybean oil with DFPL) were tested. Mayonnaises with these oils were prepared and then emulsion stability at low temperature $(-5^{\circ}C)$ were compared. The oxidative stability of vegetable oil by Rancimat test showed that induction time of DFPL (26.9 hr) was longer when compared with soybean oil (13.4 hr), and became longer with increase of DFPL ratio in the blended oil. Emulsion stability of mayonnaises at low temperature $(-5^{\circ}C)$ was decreased with the increase of DFPL ratio in the blended oil. But, mayonnaise with blended oil of below 20% DFPL was comparable to that with soybean oil only. Among quality characteristics of mayonnaises with soybean oil and blended oil (soybean oil 85% plus DFPL 15%) the latter showed stronger oxidative stability and less flavor reversion during high temperature treatment. This result suggested that the possibility of DFPL to substitute for vegetable oil in the preparation of commercial mayonnaise.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.147-153
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• 2018

PLGA microcapsule particles encapsulating BSA aqueous solutions were prepared using a water-in-oil-in-water emulsion method. The morphology, particle size, BSA encapsulating efficiency, and in-vitro release test were also studied using the microcapsule particles. In the outer aqueous phase, an emulsifier, e.g., PVA, was replaced with metal salts for surface solidification. Scanning electron microscopy (SEM) showed that the microcapsule particles had smooth surfaces and were between $1{\mu}m$ and $7{\mu}m$ in size. The microcapsule particle morphology was affected directly by the ratio between the polymer solution and inner aqueous solution, and composition of the outer aqueous solution. The factors also partially affected the BSA encapsulation efficiencies and in-vitro release rates. All the microcapsule particles showed an initial burst release through the in-vitro release test. On the other hand, the particles also showed a relatively long release period. Metal salts could be good choices to replace the emulsifier to solidify the microcapsule particle surfaces.

• Korean Journal of Food Science and Technology
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• v.48 no.5
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• pp.454-460
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• 2016

In this study, we investigated the possibility of Droplet digital PCR (ddPCR) for detection of foodborne pathogens. ddPCR combines partitioning of PCR reactions into several thousands or millions of individual droplets in a water-oil emulsion, and counting of positive PCR reaction using flow cytometry. Four species of foodborne pathogens, Bacillus cereus, Staphylococcus aureus, Salmonella Typhimurium and Escherichia coli O157:H7, were used to quantify the target sequence with each of the designed primers and double stranded DNA-binding Evagreen dye. All tested foodborne pathogens showed a detection limit ranging from $100fg/{\mu}L$ to $10ng/{\mu}L$. It was concluded that ddPCR could be used to detect very low concentrations of foodborne pathogens from complex food matrices. For multi-detection of target pathogens, we also tested the samples using multiplex ddPCR and obtained successful results.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.5
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• pp.2453-2457
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• 2016

Background: Dysregulation of HSP90 gene expression is known to take place in breast cancer. Here we used D,L-lactic-co-glycolic acid-polyethylene glycol-17-dimethylaminoethylamino-17-demethoxy geldanamycin (PLGA-PEG-17DMAG) complexes and free 17-DMAG to inhibit the expression of HSP90 gene in the T47D breast cancer cell line. The purpose was to determine whether nanoencapsulating 17DMAG improves the anti-cancer effects as compared to free 17DMAG. Materials and Methods: The T47D breast cancer cell line was grown in RPMI 1640 supplemented with 10% FBS. Encapsulation of 17DMAG was conducted through a double emulsion method and properties of copolymers were characterized by Fourier transform infrared spectroscopy and H nuclear magnetic resonance spectroscopy. Assessment of drug cytotoxicity was by MTT assay. After treatment of T47D cells with a given amount of drug, RNA was extracted and cDNA was synthesized. In order to assess HSP90 gene expression, real-time PCR was performed. Results: Taking into account drug load, IC50 was significant decreased in nanocapsulated 17DMAG in comparison with free 17DMAG. This finding was associated with decrease of HSP90 gene expression. Conclusions: PLGA-PEG-17DMAG complexes can be more effective than free 17DMAG in down-regulating of HSP90 expression, at the saesm time exerting more potent cytotoxic effects. Therefore, PLGA-PEG could be a superior carrier for this type of hydrophobic agent.

• Korean Journal of Veterinary Research
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• v.34 no.3
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• pp.529-536
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• 1994

To establish more specific and simple diagnostic methods for detection of the antibodies and antigens of Aujeszky's disease virus(ADV), we designed indirect dot-immunoassay(IDI) and double sandwich dotimmunoassay(DSDI) using the solid phases of nitrocellolose paper and polystyrene plate. The diagnostic efficacy of these methods was investigated. As the sensitivity of IDI was tested by various virus concentration, the specimens with the virus titer above $10^{4.0}TCID_{50}/0.2ml$ showed positive reaction, but that below $10^{1.0}TCID_{50}/ml$ revealed negative. Tonsil emulsion at the virus titer of $10^{4.5}TCID_{50}/0.2ml$ showed the highest sensitivity as diluted by 1/100. In detection of ADV antigens from the various tissues of the rats and pigs infected with ADV, IDI using monoclonal antibody showed the higher specificity as compared with IDI using polyclonal antibody and virus isolation method. The efficacy of the DSDI for detection of ADV antibody was compared with other tests. The sensitivity of DSDI was higher than virus neutralization(VN) and agar gel immunodiffusion test(AGID). Meanwhile, specificity of DSDI was lower than AGID, but similar to IDEA. In comparison with VN test, DSDI showed 96.9% agreement to VN test that is the highest of three tests. In general, application of polyclonal antibody in both tests caused the higher sensitivity but the lower specificty.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.33 no.4
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• pp.219-225
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• 2007

Bis-ethylhexyloxyphenolmethoxyphenyltrizine (BEMT) is one of the most widely used chemical UVA+UVB double absorbers in sunscreen products. But topical application of BEMT is restricted due to its defects in product. The purpose of this study is to adopt the sunscreen product of solid lipid nano-particles containing BEMT (BEMT-SLN). The particle diameters, the encapsulation efficiencies and the crystallization index (C.I.) are about 330nm, 93.3 % and the 4.3 %. As a result, in vitro penetration and release of BEMT were generally higher in O/W emulsion than the SLN formulation. However in vivo study, it was shown that the rate of release could be decreased by 80 % in the SLN formulation. The sun protection factor (SPF) of the SLN formulation increased by 100 % in the in vitro UV protection test. Therefore, SLN formulation potentiated the UV-blocking power of BEMT. This study suggest that SLN can be used for the encapsulation of BEMT.

• Bulletin of the Korean Chemical Society
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• v.35 no.12
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• pp.3509-3513
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• 2014

Phospholipase D (PLD) catalyzed the generation of phosphatidic acid (PA) from phosphatidylcholine (PC) at the outer layer of the vesicles prepared through layer by layer via a double emulsion technique. The generation induced a curvature change in the vesicles, which eventually led them to fuse each other. The ratio of two-fatty-acid-tail ethanolamine (PE) to one-fatty-acid-tail ethanolamine (PE) was found to acquire the condition where the mixed-phospholipid vesicles were stable identically with pure two-fatty-acid-tail PC. The effect of the outer-layer mixture on the PLD-induced vesicle fusion was investigated using the fluorescence intensity change. 8-Aminonaph-thalene-1,3,6-trisulfonic acid disodium salt (ANTS) and p-Xylene-bis(N-pyridinium bromide) (DPX) were encapsulated in the vesicles, respectively, for the quantification of the fusion. The fluorescence scale was calibrated with the fluorescence of a 1/1 mixture of ANTS and DPX vesicles in NaCl buffer taken as 100% fluorescence (0% fusion) and the vesicles containing both ANTS and DPX as 0% fluorescence (100% fusion), considering the leakage into the medium studied directly in a separate experiment using vesicles containing both ANTS and DPX. The fusion data for each composition were acquired with the subtraction of the leakage from the quenching. From the monitoring, the vesicle fusion caused by the PLD reaction seems dominantly to occur rather than the vesicle lysis, because the composition effect on the fusion was observed identically with that on the change in the vesicle structure. Furthermore, the diameter measurements also support the fusion dominancy.

• Elastomers and Composites
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• v.37 no.1
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• pp.31-38
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• 2002

Polymerization of carboxylated styrene-butadiene latex takes longer time than that of acrylic emulsion due to delocalization of radical in butadiene unit having conjugated double bond. A latex stability is the most important properties owing to use intact without separating polymer from base latex. For reducing polymerization time without decreasing any properties of latex, carbon tetra-chloride which has been used as the most popular chain transfer agent was replaced to combination of tert-dodecylmercaptane and ${\alpha}$-methylstyrene dimer. The replacement yielded reducement or 2 hr in polymerization time. In the increment step, charge amount of acrylic acid was limited to 0.3 part to restrain viscosity enhancement. Just after initial step, addition of 0.1 part acrylamide prevent polymer chain from diffusing between two region followed by giving hardness and final good adhesive force to latex particles.