• KSBB Journal
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• v.16 no.1
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• pp.24-29
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• 2001

Recently hepatocyte-based bioartificial liver (BAL) and hepatocyte transplantation have been actively investigated to treat acute hepatic failure. The BAL acts as a bridge to provide patients with more time until a donor organ becomes available for transplantation or until their own liver can be regenerated. In this study, we manufactured a polyurethane foam (PUF) using 15% NCO-prepolymer with a pore opening that allows it to be used as a hepatocyte immobilizing material. Cubes of PUF (3 mm dim.) were seeded with rat primary hepatocytes at a density of 5.5$\pm$1.1$\times$ $10^6$ cells/$cm^3$ PUF by centrifuging them together. The cell laden PUF cubes were packed into a prototype reactor and perfused with a hormonally defined medium for a week. Hepatocytes in the pores of the PUF formed spheroids that showed stable ammonia removal and urea synthesis activities. The albumin production level was comparable to other BAL systems. The PUF packed hepatocyte bioreactor has the potential to be used as a BAL.

• Journal of Labour Economics
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• v.28 no.3
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• pp.77-109
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• 2005

On the basis of the Korea Labor and Income Panel Survey for the 1997 through 2003 period, this paper investigates if the income distribution has become more bi-polarized since the recent financial crisis. The polarization measure developed by Esteban and Ray(l994) and Duclos, Esteban, and Ray(2004) indicates that the distribution of total income has become much more bi-polarized than unequalized for the entire sample period. Second, the rapid increase in the bi-polarization measure is attributed to the enhanced within-group homogeneity among the lower-income group as well as the widening gap between the two groups in the mean income level. Third, no such pattern exists in the distribution of labor income. Overall, the findings in the current study would support the hypothesis of a centrifuging society which is characterized by the slow disappearance of the middle class and the formation of two poles and which is observed in the United States and the United Kingdom among others.

• Korean Journal of Materials Research
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• v.27 no.2
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• pp.100-106
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• 2017

Nanosized and aggregated $Y_2O_3:Eu$ Red phosphors were prepared by template method from metal salt impregnated into crystalline cellulose. The particle size and photoluminescent property of $Y_2O_3:Eu$ red phosphors were controlled by variation of the calcination temperature and time. Dispersed nanosol was also obtained from the aggregated $Y_2O_3:Eu$ Red phosphor under bead mill wet process. The dispersion property of the $Y_2O_3:Eu$ nanosol was optimized by controlling the bead size, bead content ratio and milling time. The median particle size ($D_{50}$) of $Y_2O_3:Eu$ nanosol was found to be around 100 nm, and to be below 90 nm after centrifuging. In spite of the low photoluminescent properties of $Y_2O_3:Eu$ nanosol, it was observed that the photoluminescent property recovered after re-calcination. The dispersion and photoluminescent properties of $Y_2O_3:Eu$ nanosol were investigated using a particle size analyzer, FE-SEM, and a fluorescence spectrometer.

• 한국해양학회지
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• v.1 no.1_2
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• pp.14-21
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• 1966

A phytoplankton study in the Korean waters has been commenced from 1964 as parts of the primary production studies in the Korean waters and the cruise for the cooperative studies of the Kuroshio from 1965 to 1968. Samples are taken by dipping 300-500 ml of sea water from the surface, and then fixed by adding neutralized formalin. The phytoplankton identification and cell counts are made on samples carefully after concentrated by decanting and centrifuging in the laboratory. This report deals with the surface phytoplankton obtained during the period of August 14-27, 1965 at twenty-three stations in the Korea Strait. Fifty nine species in seventeen genera of diatoms are detected from the samples collected at the stations. Among them seven species in five genera are considered to be purely neritic or cold water species and eight species in four genera are oceanic species of the Kuroshio. The highest phytoplankton standing crops are found in the sea area neighboring coastal waters of southern Korea, and the species distribution show anomalies in normally oceanic species being confined to neritic waters. There are distinct genera compositions of eastern, western and intermediate sea areas in the Kore Strait.

• Plant Biotechnology Reports
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• v.4 no.1
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• pp.49-52
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• 2010

A DNA extraction method using Chelex 100 is widely used for bacteria, Chlamydomonas, and animal cell lines, but only rarely for plant materials due to the need for additional time-consuming and tedious steps. We have modified the Chelex 100 protocol and successfully developed a rapid and simple method of DNA extraction for efficient PCR-based detection of transgenes from a variety of transgenic plant and algal species. Our protocol consists of homogenizing plant tissue with a pestle, boiling the homogenized tissue in a microfuge tube with 5% Chelex 100 for 5 min, and centrifuging the boiled mixture. The supernatant, which is used for PCR analysis, was able to successfully amplify transgenes in transgenic tobacco, tomato, potato, Arabidopsis, rice, strawberry, Spirodela polyrhiza, Chlamydomonas, and Porphyra tenera. The entire DNA extraction procedure requires <15 min and is therefore comparable to that used for bacteria, Chlamydomonas, and animal cell lines.

• 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.

• Korean Journal of Food Science and Technology
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• v.27 no.3
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• pp.348-352
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• 1995

The antioxidant activities and properties of freeze-dried(FD) coffee were examined. Aqueous solution of FD coffee showed antioxidant activity on lard, and the antioxidant effect increased with increasing the addition of the aqueous solution. In contrast, FD coffee powder did not showed antioxidant activity on lard. The antioxidant activities of aqueous FD coffee solution of different solid contents were closely correlated with the water activity(Aw). Aqueous FD coffee solution with high Aw(over 0.98) showed strong antioxidant activity. Emulsifiers added to lard did not change the antioxidant activities of aqueous FD coffee solution. The lard that aqueous FD coffee solution was removed from by centrifuging had an antioxidant activity as the lard with aqueous FD coffee solution did. The spectrophotometry test showed that unidentified nonpolar components of FD coffee were introduced into lard.

• Journal of Pharmaceutical Investigation
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• v.32 no.1
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• pp.13-19
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• 2002

Water-lipid soluble multivitamin formulations were widely used to reduce the disease and stress of animals as husbandry has made a remarkable progress in recent. But the efficiency of these formulations is far from satisfactory. So, this study was attempted to develop the physically and chemically stable and useful multivitamin o/w emulsion. Multivitamin o/w emulsion composed of water, soybean oil (10%, v/v), vitamin A, D, E, K, $B_2,\;B_6,\;B_{12}$ and panthenol. To make a stable o/w emulsion, the egg lecithin (2%, w/v) and glycerin (2.5%, w/v) were used for emulsifier and thickening agent, respectively. The oil in water emulsion system was manufactured by microfluidizer and the physicochemical stability of this emulsion was evaluated. The average particle size and interfacial tension were measured. From the result of interfacial tension tested, critical micelle concentration of the egg lecithin was 0.5% (w/v) and optimal concentration for the preparation of emulsion was 2% (w/v). The mean particle size was about $0.6\;{\mu}m$ which was suitable for injections. Short-term accelerated stability as physical stability study was tested by centrifuging and freeze-thawing the emulsion samples. The additions of vitamins resulted in the increment of particle size and reduction of physical stability of emulsion. But it is not an enormous problem for the stability of emulsion. Also, we have performed the long-period preservation stability test for the vitamins. All vitamins were analysed by HPLC. The result of storage under $4^{\circ}C$ and dark conditions demonstrated that all vitamins were maintained stable at least 16 weeks, except for vitamin $B_{12}$.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.18 no.3
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• pp.18-25
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• 2005

Objectives: It has a growing interest in the prevention and medical treatment of allergic rhinitis. According to many studies, it's known that Sinicheongpye-um has the inhibitory effect on the allergic rhinitis. We have studied effect of the mice on OVA-induced Production of IL-4, IL-5, $Interferone-{\gamma}$ by Murine Splenocytes and effect of OVA-induced Total IgE. Methods: Mixing Ovalbumin(OVA) $10{\mu}g$ into PBS(phoshate buffered saline) and $Al(OH)_3$, gel solution and changing into $1\;m{\ell}$, we made it into OVA solution. That was administered to normal group. After the last administration into abdominal cavity, we caused allergic rhinitis in nasal cavity of mouse of control group and sample group administering 0.1% solution dropwise 3 times a day for 7 days. Keeping separated serum at -20 degree and after refloating spleen cells, cultivating the cells and centrifuging the upper liquid and keeping it at -20 degree, we measured the amount of IL-4. IL-5, $Interferone-{\gamma}$ and OVA-induced Total IgE by ELISA. Results: 1. In Total IgE, Sinichengpae-um treated group was proved significant inhibitory effect.(p<0.05) 2. In IL-4 study, Sinichengpae-um treated group was proved significant inhibitory effect.(p<0.005) 3. In IL-4 study, Sinichengpae-um treated group was proved significant inhibitory effect.(p<0.001) 4. In $Interferone-{\gamma}$ study, Sinichengpae-um treated group showed a increasing tendency. Conclusion: Based on the above result, it is considered that Sinichengpae-um has the inhibitory effect on the allergic rhinitis of mice and suggested thai it could be used in relieving patients of the symptoms which are caused by allergic rhinitis.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.271-278
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• 2006

We used polymers of alternating cationic and anionic nature to build up shells on fiber surfaces, strengthen the worn-out fibers and improve paper properties made from such fibers. OCC and ONP pulps were either dipped or salted out in the cationic polyallylamine, polyacrylamide and starch solutions. After centrifugal drying, these were followed by treatments in anionic polyacrylic acid, poly-acrylamide, and starch solutions, respectively. The shell-enhanced fibers were formed into handsheets and their physical properties evaluated. The results show that building multiple shells on worn-out fiber surfaces can strengthen the fibers and paper. The simpler and more practical impregnation-centrifuging treatment provided the desired effects, whereas salting out the polymers produced somewhat superior fibers. The latter process, were impractical, however. The first pair of polymeric shells imparted marked strength improvement, whereas later layers had diminishing efficacies. Overall, the methods can improve fiber quality, attaining paper strength requirements without resorting to expensive measures. Alternate cationic polymer and filler powders were also deposited on fiber surface based on the micriparticle system in an anticipation of stiffness gains. Platy minerals, such as montmorillonite, bentonite, sericite, clay and talc were added following cationic PAM. After dewatering of polymer-pigment shelled fiber of one to 3 pairs of layers, handsheets either calendered or uncalendered were evaluated. The results indicate that regardless of calendaring, stiffness of the handsheets did not improve appreciably while certain other strength properties showed gains. We also attempted the novel starch gel filler addition method wherein tapioca starch and filers (PCC, sericite or clay) were mixed at high solids content of 50% and cooked until gelatinized. The filled handsheets were dried under various conditions and then tested for their properties. Improvements in strengths of modified filled paper were observed.