• Journal of the Society of Cosmetic Scientists of Korea
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• v.36 no.2
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• pp.105-113
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• 2010

This study introduces a flexible approach to enhance skin permeation by using ethosomes with deformable lipid membranes as well as controllable sizes. To demonstrate this, a set of ethosomes encapsulating an anti-hair loss ingredient, Triaminodil$^{TM}$, as a model drug, were fabricated with varying their size, which was achieved by solely applying the different level of mechanical energy, while maintaining their chemical composition. After characterization of the ethosomes with dynamic light scattering, transmission electron microscopy, and deformability measurements, it was found that their membrane deformability depended on the particle size. Moreover, studies on in vitro skin permeation and murine anagen induction allowed us to figure out that the membrane deformability of ethosomes essentially affects delivery efficiency of Triaminodil$^{TM}$ through the skin. It was noticeable in our study that there existed an optimum particle size that can not only maximize the delivery of the drug through the skin, but also increase its actual dermatological activity. These findings offer a useful basis for understanding how ethosomes should be designed to improve delivery efficiency of encapsulated drugs therein in the aspects of changing their length scales and membrane properties.

• Proceedings of the Ginseng society Conference
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• 1988.08a
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• pp.1-10
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• 1988

Previously. we reported that the intraperitoneal administration of ginseng crude saponin increased: (I) nuclear RNA polymerase activity. (2) nuclear RNA synthesis. (3) cytoplasmic RNA synthesis. (4) cytoplasmic heavy polyrioosome content. (5) amino acid incorporation in vitro of microsome and polysome isolated rat liver. and (6) the incorporation rate of labeled amino acids into serum protein. In addition, a spectacular increase in the rough endoplasmic reticulum of hepatocyte administered crude saponin for four weeks orally was shown through electron microscopy. An increase in polysomal content in membrane-hound ribosome was shown through ultracentrifugation. Recently, successive intraperitoneal. administration .of $ginsenosid-Rb_2$ was given to streptozotocin (STZ) diaoetic rats of hypoproteinemia. The blood urea nitrogen and hepatic urea concentration were decreased significantly. The total protein and alhumin levels in the serum were increased in comparison to control values. In contrast. the $ginsenoside-Rb_2$ treated group of STZ diahetic rats showed a significant increase in liver RNA. total ribosome and membrane-bound ribosomal contents. The administration of $ginsenoside-Rb_2$ increased the incorporation rate of labeled - precursor into total serum protein. Additionally $ginsenoside-Rb_2$ improved the nitrogen balance of diabetic rats. On the bases of these experimental results, ginseng saponin has a metabolic stimulatory or anabolic action on RNA and protein synthesis.

• Journal of the Korean Magnetics Society
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• v.16 no.2
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• pp.140-143
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• 2006

Single crystalline $CoFe_2O_4$ thin films on (100) MgO substrates were fabricated using a rf magnetron sputtering method. The deposited films were investigated for their crystallization by X-ray diffraction, Rutherford back-scattering spectroscopy and field emission scanning electron microscopy. When a cobalt ferrite film was deposited at the substrate temperature of $600^{\circ}C$, squared grains of about 200 nm were uniformly distributed in the film. However, the grains became irregular and their sizes also varied from 30 to 150 nm when the substrate temperature was $700^{\circ}C$. Hysteresis loops of a film deposited at $600^{\circ}C$ showed that the magnetically easy axis of the film was perpendicular to the substrate surface. Except for the squareness ratio, magnetic properties of the cobalt ferrite films grown by the present rf sputtering method were as good as those of the films prepared by a laser ablation method: The in-plane and perpendicular coercivities were 283 and 6800 Oe, respectively. As the thickness of the deposited film increased twice, the saturation magnetization became double but the coercivity remained unchanged. However, deposition of the Co ferrite films with a higher rf powder decreased the squareness ratio and the perpendicular coercivity of the films.

• Journal of the Korean Vacuum Society
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• v.19 no.3
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• pp.224-229
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• 2010

Indium oxide $(In_2O_3)$ thin films have been prepared on glass substrate by using radio-frequency reactive magnetron sputtering with changing the oxygen flow ratio. The substrate temperature was kept at a fixed value of $400^{\circ}C$, and the sputtering gas and reactive gas were supplied with argon and oxygen, respectively. The oxygen partial flow ratio was varied by controlling the amount of oxygen with respect to the total mixed gases, 10%, 20%, 30%, 40%, and 50%. The optical, electrical, and structural properties of the deposited thin films were investigated by using ultraviolet-visible-near infrared spectrophotometer, Hall measurement, and X-ray diffractometer and scanning electron microscopy. The $In_2O_3$ thin film deposited at 20% of oxygen flow ratio showed an average transmittance of 86% in the wavelength range of 430~1,100 nm, an electrical resistivity of $1.1{\times}10^{-1}{\Omega}cm$. The results show that the transparent conducting films with optimum conditions can be achieved by controlling the oxygen flow ratio.

• Food Science and Preservation
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• v.15 no.1
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• pp.9-14
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• 2008

This study compared microbial load, texturre, histological properties, and sensory characteristics of gamma-irradiated (20 kGy) Kimchi and freeze-dried Kimchi under condition; of long-tenn storage. immediately after irradiation, no aerobic bacteria were detected, but microbial load of freeze-dried Kimchi decreased by only 1 log cycle in comparision with the nonirradiated control sample. The firmness of irradiated Kimchi was significantly higher than that of rehydrated freeze-dried Kimchi (p<0.05). Scanning electron microscopy showed collapse of the microstructure in epidermis tissues of rehydrated Kimchi. 'The sensory scores for color, texture, and taste of irradiated Kimchi were higher than those for rehydrated freeze-dried Kimchi.

• Korean Journal of Materials Research
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• v.25 no.8
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• pp.423-428
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• 2015

Impedancemetric $NO_x$ (NO and $NO_2$) gas sensors were designed with a stacked-layer structure and fabricated using $LaCr_xCo_{1-x}O_3$ (x = 0, 0.2, 0.5, 0.8 and 1) as the receptor material and $Li_{1.3}Al_{0.3}Ti_{1.7}(PO_4)_3$ plates as the solid-electrolyte transducer material. The $LaCr_xCo_{1-x}O_3$ layers were prepared with a polymeric precursor method that used ethylene glycol as the solvent, acetyl acetone as the chelating agent, and polyvinylpyrrolidone as the polymer additive. The effects of the Co concentration on the structural, morphological, and $NO_x$ sensing properties of the $LaCr_xCo_{1-x}O_3$ powders were investigated with powder X-ray diffraction, field emission scanning electron microscopy, and its response to 20~250 ppm of $NO_x$ at $400^{\circ}C$ (for 1 kHz and 0.5 V), respectively. When the as-prepared precursors were calcined at $700^{\circ}C$, only a single phase was detected, which corresponded to a perovskite-type structure. The XRD results showed that as the Co concentration of the $LaCr_xCo_{1-x}O_3$powders increased, the crystal structure was transformed from an orthorhombic phase to a rhombohedral phase. Moreover, the $LaCr_xCo_{1-x}O_3$ powders with $0{\leq}x<0.8$ had a rhombohedral symmetry. The size of the particles in the $LaCr_xCo_{1-x}O_3$powders increased from 0.1 to $0.5{\mu}m$ as the Co concentration increased. The sensing performance of the stack-structured $LaCr_xCo_{1-x}O_3/Li_{1.3}Al_{0.3}Ti_{1.7}(PO_4)_3$ sensors was found to divide the impedance component between the resistance and capacitance. The response of these sensors to NO gas was more sensitive than that to $NO_2$ gas. Compared to other impedancemetric sensors, the $LaCr_{0.8}Co_{0.2}O_3/Li_{1.3}Al_{0.3}Ti_{1.7}(PO_4)_3$ sensor exhibited good reversibility and reliable sensingresponse properties for $NO_x$ gases.

• Membrane Journal
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• v.21 no.4
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• pp.389-397
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• 2011

In this study, polymer composite membranes based on sulfonated poly(arylene ether sulfone) (SPAES) were prepared using a solution casting method with different amount of vermiculite (VMT) content. The dispersion of VMT particles in the SPAES matrix was confirmed by means of a scanning electron microscopy observation. The composite membrane containing less than 1 wt% of VMT has a smooth skin on the top and bottom, which means there is a good dispersion of VMT in the matrix. The water uptake of the composite membranes gradually increases as the temperature increases, and the results confirm that all the adsorbed water is bound water because VMT has a strong water affinity on account of its high cation exchange value. A composite membrane with a VMT content of less than 1 wt% increases the proton conductivity and reduces the methanol permeability. Of all the composite membranes, the membrane SPAES/VMT 1.0 has the best fuel cell performance in terms of membrane selectivity. The performance value of SPAES/VMT 1.0 is double that of Nafion 112, which suggests that SPAES/VMT1.0 could be an excellent candidate for direct methanol fuel cells.

• Membrane Journal
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• v.21 no.4
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• pp.377-388
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• 2011

Flat sheet microfiltration membranes were prepared with polysulfone (PSF), polyethersulfone (PES), and polyphenylsulfone (PPS) by an immersion precipitation phase inversion method. In this method, dimethyl formamide (DMF) and polyvinylpyrrolidone (PVP) were used as a solvent and a wetting polymer additive, respectively. 2-butoxyethanol (BE) was used as a nonsolvent additive catalyst to form pore. The morphology of membranes was investigated by scanning electron microscopy and micropermporometer. The permeability of the membranes was evaluated with the flux of pure water. When the BE was added, the pore size of membranes became larger than blank membranes. The changes in the morphology of membrane due to the BE addition depend on polymer structure. All membranes have similar mean pore size and porosity. The mean pore sizes of PSF, PES, and PPS membranes were 0.282, 0.330 $0.308{\mu}m$, respectively. The porosities of PSF, PES and PPS membranes were 68.5, 66.1, 66.4%, respectively. However, the PPS membrane showed higher pore density on surface and narrower pore size distribution than PSF or PES membrane does. As a result, the pure water flux of PPS membrane ($357L/m^2\;hr$) was higher than that of PSF ($196L/m^2\;hr$) or PES membrane ($214L/m^2\;hr$).

• Membrane Journal
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• v.19 no.4
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• pp.310-316
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• 2009

The degradation characteristics of cross-linked lactide/hyaluronic acid (LA/HA) membranes were investigated for purpose of applying to tissue engineering. The lactide/hyaluronic acid cross-linked with 1,3-butadiene diepoxide (BD) and 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) was degradated in deionized water in water bath at $37^{\circ}C$. As the LA/HA mole ratio or crosslinking agent concentration decreased, the degradation rate of the crosslinked membranes increased. In order to investigate the structure change of the membrane in the degradation process, the control sample and 3, 6, 9 days-degradated samples were analysed by the nuclear magnetic resonance spectroscopy. In case of the membranes crosslinked with EDC, the HA-EDC bonding structure was degradated slowly whereas the HA-LA bonding structure was degradated quickly and dissappeared completely after 6 days. In case of the membranes crosslinked with BD, all the crosslinked bonding structure degradated slowly. The HA-BD bonding structure maintained its original state about 89, 83% in case of 3, 6 days-degardated samples respectively whereas the HA-LA bonding structure maintained its original state about 83, 65%. The scanning electron microscopy of the degradated membranes showed that the pore density in the surface, and the structure in the surface and cross section, of the before and after-degradation membranes did not change greatly, so the membranes was shown to be applied to materials for tissue engineering.

• Membrane Journal
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• v.27 no.6
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• pp.499-505
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• 2017

The increasing number of natural disasters resulting from anthropogenic greenhouse gas emissions has prompted the development of a gas separation membrane. Carbon dioxide ($CO_2$) is the main cause of global warming. Organic polymeric membranes with inherent flexibility are good candidates for use in gas separation membranes and poly(dimethyl siloxane)(PDMS) specifically is a promising material due to its inherently high $CO_2$ diffusivity. In addition, poly(vinyl pyrrolidine)(PVP) is a polymer with high $CO_2$ solubility that could be incorporated into a gas separation membrane. In this study, poly(dimethyl siloxane)-poly(vinyl pyrrolidine)(PDMS-PVP) comb copolymers with different compositions were synthesized under mild conditions via a simple one step free radical polymerization. The copolymerization of PDMS and PVP was characterized by FTIR. The morphology and thermal behavior of the produced polymers were characterized by transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Composite membranes composed of PDMS-PVP on a microporous polysulfone substrate layer were prepared and their $CO_2$ separation properties were subsequently studied. The $CO_2$ permeance and $CO_2/N_2$ selectivity through the PDMS-PVP composite membrane reached 140.6 GPU and 12.0, respectively.