• Food Science and Preservation
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• v.16 no.5
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• pp.605-611
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• 2009

Korean Baechu cabbage(known as Chinese cabbage) brined in 0%, 5% and 10% (all w/v) salt solutions were packed using high-density polyethylene film (HDPE-film), low-density polyethylene film (LDPE-film), or Mirafresh film (MF-film, US patent No. 5972815), and stored at 4C for 4 weeks. Changes in pH and salinity, and microorganism counts (lactic acid bacteria and total bacteria), were investigated. There was no significant difference in the pH change in cabbage stored using various films when the vegetables were not salted. However, the pH was most stable in Baechu cabbage prepared using 10% salt solution. Cabbage treated with 0%, 5%, and 10% salt showed salinity values of 0.83%, 1.17% and 1.62%(all w/w), respectively, after 4 weeks of storage by LDPE-film. When cabbage was treated with the highest concentration of salt solution, the count of lactic acid bacteria increased but that of total bacteria decreased. The pH from pH 6.10 to pH 4.32, pH 5.68, and pH 5.92 in brined cabbage packed in HDPE-film, LDPE-film, and MF-film, respectively, after 4 weeks. When MF-film was used, the pH showed the greatest stability of all films tested, regardless of the concentration of salt solution employed in brining. The counts of lactic acid bacteria and total bacteria increased by all tested films during storage. Cabbage packed by MF-film showed the lowest increase in bacterial counts. In conclusion, MF-film was found to be the most effective packaging material for Baechu cabbage and brining in 10% salt solution was optimal to enhance the shelf life of the vegetable. LDPE-film was more effective than was HDPE-film for storage of brined cabbage.

• Journal of Oral Medicine and Pain
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• v.20 no.2
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• pp.429-447
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• 1995

This study was designed to determine the most effective concentration of fluoride and levels of laser irradiation for the remineralization of decayed teeth. After irradiation with a pulsed Nd:YAG laser and the topical application of fluoride, phosphate and fluoride concentration in enamel were measured. And then the changes on surface enamel using an scanning electron microscope were observed. Samples by extraction healthy, permanent, mandibular bovine teeth with no caries were obtained. Among them 371 healthy samples were selected and artificial carious lesions were made. 20 samples were assigned to each experimental group. After irradiation with a pulsed Nd:YAG laser with total energy densities of 10J/$\textrm{cm}^2$, 20J/$\textrm{cm}^2$ for each group. On the teeth, 2% NaF, 1.9% NH4F, 1.6% TiF4 Elmex gel(amine fluoride) and 1.23% APF gel were applied. After pH circulatory procedures, concentrations of fluoride with and Ionalyzer (Orion Research, Model 901, USA) and phosphates with an Uv/V is spectrophotometer (Uvikon 860, Kontrom Co, Switzerland) were measured. By etching the teeth in layers and measuring fluoride concentrations, a profile of fluoride penetration according to depth could be developed. And also the changes on the surface of the enamel using an electron scanning microscope were observed. The comparative analysis yielded the following results : 1. Phosphate concentration was low in all groups compared with the control group except for teeth treated Elmex gel, irradiated with 10J/$\textrm{cm}^2$ and 30J/$\textrm{cm}^2$ energy densities. Teeth treated with APF gel and 30J/$\textrm{cm}^2$ irradiation gad the lowest phosphate concentration. 2. Among all groups, fluoride concentrations in tooth enamel were highest in APF gel and NaF groups irradiated at 30J/$\textrm{cm}^2$. The APF gel group had the highest fluoride concentrations across all energy densities. 3. In the APF gel group, and the NaF group, the greater the energy density of the laser, the higher the fluoride concentrations in the enamel. 4. In all groups, the concentration of fluoride in the enamel by depth tended to decrease with depth. 5. Under the scanning electron microscope, under the condition of irradiation with 20J/$\textrm{cm}^2$, enamel crack was detected for the first time. In the NH4F group, spherical deposits were found on the surface of the enamel, and in the TiF4 group the surface of enamel was covered with an irregular, thin membranous mass in places. In the APF gel and NaF groups irradiated with 10J/$\textrm{cm}^2$, spherical and irregular particles covered the teeth. When these groups were irradiated at 20J/cm2, they were covered with amorphous crystals. These results suggest that one could obtain more effective anticariogenic effects without damage to teeth when less than 20J/$\textrm{cm}^2$ energy densities and APF gel are used.

• Journal of Bio-Environment Control
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• v.16 no.4
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• pp.415-419
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• 2007

This study was conducted to compare the storability of some sprout vegetables; alfalfa, broccoli, radish, red-cabbage, and red-radish, packed with 50 low density polyethylene (LDPE) film in MA storage. Most of all 5 different sprout vegetable crops maintained the fresh weight higher than 99% until 10 days storage at 2 and $8^{\circ}C$. The carbon dioxide concentration in packages was higher at 8 than at $2^{\circ}C$. It was higher in radish and red-radish sprouts than other crops. As the oxygen concentration showed opposite trends to carbon dioxide, that of radish and red-radish sprouts decreased more than 3% after 3 days in 8 storage. Ethylene concentration in the packages of alfalfa was 0.1 ppm, significantly higher than other four crops with less than 1.0 ppm. Temperature treatment, however, did not influence the ethylene concentration in packages. The radish and red-radish sprouts, with lowest oxygen concentration in package, showed lowest off-flavor compared to the others. The visual quality of these sprouts in packages showed higher at $2^{\circ}C\;than\;at\;8^{\circ}C$ and was maintained the highest in radish sprouts, followed by red-radish, broccoli, red-cabbage, and alfalfa sprouts in that order. In conclusion, as the sprout vegetables have different shelf-life, of which radish was $4{\sim}5$ days longer than that of alfalfa the distributed condition of sprout vegetables should be differently controlled according to kinds of crops.

• The Korean Journal of Pharmacology
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• v.27 no.1
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• pp.33-43
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• 1991

To study the age dependent change of Na, K-ATPase in the erythrocyte of hypertensive rat, 1-kidey 1-clip hypertensive rat was made by the removal of right kidney and partial ligation of left renal artery. After 4 weeks, aged erythrocyte fraction was separated by density gradient centrifugation, and Na, K-ATPase activity and $^3H-ouabain$ binding with ghost cell membrane and ouabain sensitive Rb-uptake with whole cell were measured. 1) In the hypertensive rats, blood pressure was significantly increased to 165.5/119.0 mmHg (systolic/diastolic). Mean corpuscular volume and membrane protein(mg) per $10^9RBC$ were decreased and hemoglobin content was increased in the aged erythrocyte. 2) Na, K-ATPase activity in the solution containing 110 mM NaCl and 10 mM KCI, was decreased in hypertensive rat, and decreased in aged erythrocyte of both group. 3) Ouabain sensitive Rb-uptake by low RbCl concentration(4 mM) was slightly decreased in aged erythrocyte compared to that in young erythrocyte of each group, but slightly increased in young erythrocyte in hypertensive rat compared to that in normotensive rat. 4) Ouabain sensitive Rb-uptake by high RbCl concentration(16 mM) was decreased about 30% to 50 % in aged erythrocyte in both group. And in hypertensive rat, especially in young erythrocyte it was significantly decreased compared to that in normotensive rats. 5) $^3H-ouabain$ binding at 0.13 or $1{\times}10^-6M$ ouabain concentration was slightly decreased in aged erythrocyte of normotensive rat, and significantly decreased in aged erythrocyte of hypertensive rats. 6) $^3H-ouabain$ binding at 6 or $64{\times}10^-6M$ ouabain concentration is slightly decreased in aged erythrocyte of both group, but significantly decreased in young and aged erythrocyte of hypertensive rats compared to that of normotensive rats. The present results suggest that (1) in the young erythrocyte of hypertensive rat, the alterations of Na-pump activity that slightly increased in weak stimulation and inhibited in strong stimulation, may be related to increased molecular activity and the decrease in the number of low affinity site without change in high affinity site, (2) in the aged erythrocyte of normotensive rat, inhibited Na-pump may be related to the change in molecular activity of pump. (3) And in the aged erythrocyte of hypertensive rat, it may be related to the decrease in the number of high and low affinity site as well as the change in molecular activity

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2232-2237
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• 2007

Steam reforming and catalytic reforming of $CH_4$ conversion to produce synthesis gas require both high temperatures and high pressure. Non-thermal plasma is considered to be a promising technology for the hydrogen rich gas production from methane. In this study, three phase AC GlidArc plasma system was employed to investigate the effects of gas composition, gas flow rate, catalyst reactor temperature and applied electric power on the $CH_4$ and $H_2$ yield and the product distribution. The studied system consisted of three electrode and it connected AC generate power system different voltages. In this study, air was used for the partial oxidation of methane. The results showed that increasing gas flow rate, catalyst reactor temperature, or electric power enhanced $CH_4$ conversion and $H_2$ concentration. The reference conditions were found at a $O_2$/C molar ratio of 0.45, a feed flow rate of 4.9 ${\ell}$/min, and input power of 1kW for the maximum conversions of $CH_4$ with a high selectivity of $H_2$ and a low reactor energy density.

• Journal of Pharmaceutical Investigation
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• v.39 no.3
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• pp.167-171
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• 2009

Poly(lactic-co-glycolic acid) (PLGA) microspheres have been a useful tool as a controlled drug delivery system for peptides and proteins. Recently, porous microspheres have gained great attention as inhalation drug delivery system due to their low aerodynamic densities. Here, we report highly porous PLGA microspheres, which were prepared by using a single o/w emulsification/solvent evaporation method. Two types of porogen, i.e., (i) extractable Pluronic F127 and (ii) gas foaming salt of ammonium bicarbonate, were used to induce pores on the surface of PLGA microspheres. The respective preparation conditions on dp/cp ratio and porogen concentration were determined by the previous preliminary experiments, and other preparation factors were further optimized on the basis of PLGA Mw and porogen type. The morphological features examined by scanning electron microscope (SEM) show these porous microspheres have highly porous surface structure with a diameter range of 20${\sim}$30 ${\mu}$m. These highly porous PLGA microspheres, which have much lower density, would be a practical aerosol system for pulmonary drug delivery.

• The Journal of Engineering Geology
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• v.3 no.2
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• pp.203-214
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• 1993

Underground Injection Control regulations for Class I injection wells require that the vertical dufusion be considered as a mechanism for transport of contaninants in evaluating containment Due to the low permeability in the confining aquitard, the movement of contaminants over the long term is controlled by the molecular diffusion. The movement can be predicted, using the Fick' S second law of diffusion. The diffusion coefficient in Fick' s law has been determined experimentally in this study. Instantaneous injection of $^{51}Cr$ was used to trace the distribution of Cr(VI) in soil plugs and an analytical solution was applied to calculate the diffusion coefficients. This study shows the effect of environmental factors, such as temperature, chloride concentration, applied amount of $^{51}Cr$, and bulk density of injection formations on diffusion of Cr(VI)

• YAKHAK HOEJI
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• v.44 no.1
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• pp.71-79
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• 2000

Curcumin, the yellow pigment in turmeric, curry and mustard, has anti-inflammatory and anti-carcinogenic activities. In this study; we investigated the hypocholesterolemic and anti-atherogenic effect of curcumin in rabbits. Hypercholesterolemia was induced by feeding high cholesterol diet to male rabbits for 30 days, and the animals were then fed high cholesterol diet containing 0.1% (w/w) or 0.5% (w/w) curcumin for additional 30 days. Supplementation of 0.l% curcumin tended to lower serum total cholesterol and low density lipoprotein (LDL)-cholesterol levels and inhibit serum lipid peroxidation. In the 0.5% curcumin-supplemented group, serum total cholesterol was significantly lowered by 11.7%, LDL-cholesterol by 12.8% and lipid peroxidation by 47.9% compared to the control group. Hepatic cholesterol and triglyceride contents were also significantly lowered by 50.6% and 37.4%, respectively compared to the control group. Lipid staining of the arteries isolated from the curcumin-treated rabbits showed that curcumin significantly decreased formation of fatty streaks and atheromatous plaques on the intima of the arteries. These results demonstrated that curcumin lowered serum cholesterol concentration, hepatic cholesterol and triglyceride contents, and accumulation of cholesterol in the artery These cholesterol lowering effects of curcumin, together with its anti-oxidative and anti-inflammatory activities, may play some important roles in preventing atherosclerosis.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.189-192
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• 2000

The objective of this study was to investigate the effect of high content of light-absorbing pigments on overall photosynthetic efficiency in high density microalgal cultures. The light harvesting complex II (LHC II) regulating gene of Rhodobacter sphaeroides, photosynthetic purple bacterium, was removed to construct a mutant strain that had less pigment content. The mutant and wild type strains were cultured under various light intensity by adjusting the distance from the light source. The productivity of the mutant strain was higher at high light intensity (over 118 ${\mu}E/m^2/s$) compared with one of the wild type , and was lower at low light intensity (34 ${\mu}E/m^2/s$). Especially, the concentration of LHC II mutant strain was 56% higher at 118 ${\mu}E/m^2/s$. The reduction of per cell pigment contents in the mutant strain lessened the degree of the mutual shading and thus enhanced the overall photosynthetic efficiency.

• Journal of the Korean Vacuum Society
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• v.13 no.1
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• pp.29-33
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• 2004

In this paper, we investigated the ultra-low temperature(<$150^{\circ}C$) polycrystalline silicon film on plastic substrate application using RF-magnetron sputtering and excimer laser annealing. Amorphous silicon films were deposited using Ar/He mixture gas at $120^{\circ}C$ and in-film argon concentration was less than 2%, which was measured to Rutherford Backscattering Spectrometry. At energy density 320mJ/$\textrm{cm}^2$, RMS roughness was 267$\AA$ and UV crystallinity was 62%. The grain size varies from 50nm to 100nm after excimer laser irradiation.