• Microbiology and Biotechnology Letters
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• v.22 no.3
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• pp.290-295
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• 1994

Micelle, liposome and polyethylene glycol(PEG) were employed to reduce the cell mem- brane toxicity of Amphotericin B(Amp. B). Cholesterol-sulfate which can form a mixed micelle with Amp. B molecules was found very effective for the reduction of Amp. B toxicity. 0.01% of cholesterol-sulfate could reduce the toxicity of 5X 10$^{-6}$ M Amp. B by 90%. The required concent- ration of cholesterol-sulfate for the toxicity reduction was proportionally increased with increasing Amp. B concentration. PEG was also effective on the reduction of Amp. B toxicity. 2% PEG was required for the reduction of toxicity by 50%, regardless of Amp. B concentration. The liposome system showed an effective reduction of Amp. B toxicity on RBC, maintaining the antibiotic effect on Candida albicans as free drugs. This seems to be due to the fact that liposome bilayer plays a role of buffer system between ergosterol of fungi cell membrane and cholesterol of red blood cell membrane, which leads the redistribution of Amp. B between them, as the result, the reduction of drug toxicity on cell membrane.

• Journal of the Korean Applied Science and Technology
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• v.18 no.2
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• pp.118-126
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• 2001

Micelle formation and adsorption at the $Ti0_{2}$ interface of a series of polystyrene-polythylene oxide(PS-PEO) block copolymer in aqueous solution was studied using fluorescence probing and small-angle X-ray methods. Further, the stability of aqueous $Ti0_{2}$ dispersion in the presence of copolymer was investigated by microelectrophoresis, optical density and sedimentation measurements. The dissolution of pyrene as fluorescent probe in aqueous surfactant solution leads to a slow decrease of the $I_{1}/I_{3}$ ratio, as the copolymer concentration increase; $I_{1}$ and $I_{3}$ are respectively the intensities of the first and third vibrionic peaks in the pyrene fluorescence emission. The behaviour was due to the characteristics of the copolymers and/or to the copolymer association efficiency in water. Moreover, the adsorption at the plateau level increases with decreasing PEO until chain length. The zeta potential of $TiO_{2}$ particles decreases with increasing copolymer concentration and reaches a plateau value. Finally, stabilization using block copolymers was more effective with samples having higher weight fractions of PS block.

• Journal of the Korean Applied Science and Technology
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• v.13 no.1
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• pp.41-46
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• 1996

Durable softening water repellents such as PODCWs were prepared by blending cationized compound of poly(octadecyl methacrylate-co-2-diethylaminoethyl methacrylate), of which synthetic methods were reported in the previous paper, activated polythylene, waxes, and emulsifiers. Water repellency of prepared PODCWs was measured by performing water repellent finish to various fabrics, PODCWs showed a good water repellency for P/C blended fabrics and their repelling tendency was in the order of P/C blended fabrics>cotton fabrics>nylon taffeta. The initial water repellencies of PODCW-1 and PODCW-2 were 100 and $100^{-}$ points, respectively, for P/C blended fabrics. And also, PODCW-1 and PODCW-2 were confirmed as durable water repellents with the results of making little difference of water repellency as ${\pm}5$ point after and before washing.

• Bulletin of the Korean Chemical Society
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• v.21 no.6
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• pp.623-627
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• 2000

Aggregation of hydrophobically end-capped poly(ethylene oxide)s: HEURs, denoted as $C_8$$EO_{380}$$C_8$, $C_12$$CO_{600}$$C_{12}$, and $C_{18}$$EO_{860}$$C_{18}$,are described using static fluorescence, dynamic light scattering, and atomic force microscope (AFM) techniques. The CAC (critical aggregation concentration) was determined by com-paring two fluorescent peaks which were influenced by the polarity of the probe dye molecules, pyrene. The aggregation occurs in concentrations higher than 10 g/L of $C_8$$EO_{380}$$C_8$ and the CAC decreases by increasing the side chain length. The dynamic light scattering experiment shows fast mode and slow mode decays, and both are diffusive. The fast mode does not depend on the concentration, but the slow mode shows concentration dependence influenced by the formation of an aggregated structure. The hydrophobic end groups effect more dominantly than the main chains for the formation of HEUR micelles. By increasing the concentration, the HEUR micelles change their structure from spheres to rodlike micelles, and finally make fused structures, which were visualized with atomic force microscopy.

• Journal of Ginseng Research
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• v.3 no.2
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• pp.105-112
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• 1979

Effect of gibberllin on the breaking of bud dormancy of root and growth of aerial parts were investigated under laboratory and field condition for the prolongation of shoot growth duration, shortening of fruit bearing age and the increase of root yield. Drop application of GA (0.5ml of 50ppm) on rhizome of one year old root broke bud dormancy better than by low temperature. Soaking for one hour of one year old roots which wintered in the field in GA (50-200ppm) greatly accelerated the emergence of new buds while kinetin was only effective at low level (50ppm). GA substantially increased stem length in early stage and petiole length later on while kinetin increased stem diameter. Under the field condition with polythylene film tunnel (PET) in early spring the soaking in GA (50ppm for 1 hour) of rhizome of 4 year old root with replanting and dropping GA (50ppm, 1ml) on rhizome without replanting brought earlier emergence (29days) in comparison with that in the usual field. PET alone caused 14 day-early emergence. GA increased the length of stem and petiole only in early stage and replanting decreased only petiole length in later stage. Soaking in GA with replanting caused the Pronounced decrease in peduncle length, percentage of (ruin set and dry weight of reproductive organ (fruits and peduncle). Dropping without replanting showed significant decrease only in dry weight of reproductive organ. Fruit maturing was 20 days earlier than in usual held with little difference between GA and PET. It is well expected that GA could be used for early emergence of bud, shortening of root dormancy period, thinning of fruit and higher root yield according to application amount and methods.

• Food Science and Preservation
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• v.8 no.3
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• pp.252-257
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• 2001

This studies were carried out to investigate the physical properties and quality of sweet persimmon fruits which packaged with polyethylene for improvement of quality and storage. The fruits which packed 5 fruits a pack by 0.06mm PE film was maintained freshness during 120 days of storage, but those which packaged a fruit was maintained freshens during 150 days of storage, and quality of fruits was excellent during storage. It was more excellent quality of fruits packaged 5 fruits a pack with 0.08 and 0.10mm PE film than quality of those packaged by 0.06mm PE film. Hardness of fruits were decreased during storage, and the color of fruits was changed. But the fruits which packaged each with 0.08mm PE film was maitained freshens during 180 days of storage, and the quality of fruits was excellent during storage. The hardness and color of fruits were net changed during storage.

• The Korean Journal of Zoology
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• v.20 no.4
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• pp.169-177
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• 1977

Plasma albumin and hemoglobin were purified from the blood of Rhabdophis tigrinus. Both purified proteins and R. tigrinus crude plasma were injected into rabbits. The resulting antisera were tested for reactivity with plasma albumin and hemoglobin from, eight species of squamate and four species of non-squamate-vertebrate. Reactivity was detected qualitatively by immunodiffusion tests and immunoelectrophoreses. Antisera against plasma albumin and crude plasma reacted only with R. tigrinus plasma albumin. No antigen-antibody reactions were detected in plasma albumins of other species. Antiserum against R. tigrinus hemoglobin reacted strongly with eight squamate hemoglobins. It is likely that the reptilian plasma albumin has been experiencing rapid structural change and the reptilian hemoglobin molecules seem to be of high homogeneity. Thus, by immunological evidences, the structure of the hemoglobin molecule is considered to have been changing at slower rate than that of the plasma albumin in reptiles.

• Polymer(Korea)
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• v.26 no.6
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• pp.812-820
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• 2002

The positive temperature coefficient (PTC) characteristics of polymer composites were investigated with the nano-sized carbon black particles using solution tasting and melt compounding methods. The polymeric PTC composites should the electrical threshold at 35 wt% for the melt compounding method and 40 wt% for the solution casting method. The ethylene vinylacetate copolymer (EVA) composite showed a gradual increase of resistance as a function of temperature and showed a maximum at the polymer molting point. The resistance of the high-density polythylene (HDPE) composite remains unchanged with temperature but started to Increase sharply near the melting point of HDPE and showed a maximum resistance at the melting point of HDPE. The dispersion of nano-sized carbon black particles was investigated by scanning electron microscopy (SEM) and low resistance after electrical threshold, and both methods exhibited a well dispersed morphology. When the electric current was applied to the PTC composites, the resistance started increasing at the curie temperature and further increased until the trip temperature was roached. Then the resistance remained stable over the trip temperature. The secondary increase started at T$\sub$m/ of matrix polymer and kept increasing up to the trip temperature.

• Journal of Ginseng Research
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• v.15 no.2
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• pp.144-151
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• 1991

This study was conducted to elucidate the effects of light intensity using polyethylene (p.E) net shading on the specific gravity, red ginseng quality, sugar and saponin contents of ginseng root. The specific gravity significantly increased in the ginseng roots grown under the P.E net shading as compared with that of common straw shading. The red ginseng quality under the P.E net shading was improved in order of 10, 5, 15, 20, 30% of light intensity and the inside cavity and inside white part decreased remarkably as compared with those of common straw shading. The ginseng roots grown under the P.E net shading at 10% and 15% light intensity showed a significant increase in the total sugar content but a significant decrease in the reducing sugar content at 15% light intensity as compared with those of common straw shading. The amount of total saponin of ginseng roots was increased under the P.E net shading at high light intensity as compared with that of common straw shading and the ginseng roots grown under the P.E net shading at 10% light intensity showed an increase in the diol group saponin but the ratio of PT/PD was decreased. Extract contents of ginseng root under the P.E net shading was higher than those of common straw shading and the roots grown under the P.E net shading at 15% and 20% light intensity resulted in a remarkable increase in extract contents.

• Korean Journal of Food Science and Technology
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• v.44 no.5
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• pp.559-567
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• 2012

The storage quality of ready-to-eat Campbell table grapes which were packaged under modified atmospheres was investigated in order to examine the effect of high $O_2$ and $CO_2$ on the fruit. Fresh table grapes with 10-15 berries were packed into polypropylene (PP) trays and were top-sealed with polythylene terephthalate/PP film. The initial gas compositions inside the packages were air, 20% $O_2$/10% $CO_2$/70% $N_2$, and 40% $O_2$/60% $N_2$. Sealed packages with low density polyethylene film bags and perforated PP trays were also used as a further treatment and control, respectively. The quality attributes were assessed during storage at $5^{\circ}C$ for 28 days. Fruit packaged in high $CO_2$ concentration showed the lowest viable cell counts of inherent microorganisms among all samples, although they suffered from severe off-flavors. High levels of $O_2$ significantly lowered flesh weight loss and maintained the flavor of grape. In an overall sensory aspect, the high $O_2$ and $CO_2$ packages exhibited greater scores than the air and control at the end of the storage period. Other quality attributes showed no significant differences among treatments. Results suggest that packaging with an appropriate combination of high $O_2$ and $CO_2$ can be used as an effective processing treatment for improvement of the storability of ready-to-eat table grapes.