• Food Engineering Progress
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• v.21 no.1
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• pp.79-87
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• 2017

This study was carried out to extract ginsenosides in by-products from honeyed red ginseng. Response surface methodology (RSM) was used to optimize the extraction conditions. Based on D-optimal design, independent variables were ethanol (extraction solvent) concentration (30-90%, v/v), extraction temperature ($25-70^{\circ}C$), and extraction time (5-11 h). Extraction yield (Y1) and total ginsenosides (Y2) in the extract were analyzed as dependent variables. Results found that extraction yield increased with increasing extraction temperature and time, whereas it was decreased with increasing ethanol concentration. Similar trends were found for the content of ginsenosides in the extracts, except for ethanol concentration, which was increased with increasing ethanol concentration. Regression equations derived from RSM were suggested to coincide well with the results from the experiments. The optimal extraction conditions for extraction yield and total ginsenosides were an extraction temperature of $56.94^{\circ}C$, ethanol concentration of 57.90%, and extraction time of 11 h. Under these conditions, extraction yield and total ginsenoside contents were predicted to be 84.52% and 9.54 mg/g, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.4
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• pp.292-301
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• 2001

The objectives of this study were to measure the changes in soil moisture regimes and the distribution patterns of inorganic N derived from the fertigated $^{15}N$-labeled urea, and compare them with the results obtained from broadcast-applied soil under the same drip irrigation domain. In fertigated soil, a $^{15}N$-labeled urea solution of $117mg\;N\;L^{-1}$ was applied by surface drip irrigation for 4 weeks. In broadcast-applied soil, no the other hand, 4 g of $^{15}N$-labeled urea(1.87 g N) mixed thoroughly with 5 kg of soil was placed on the surface of packed soil. Soil water status was controlled by drip irrigation scheduled at soil matric potential of -50 kPa. A calibrated time-domain reflectometry probe was installed in the soil vertically 15 cm apart from a drip emitter to control drip irrigation. About 60% of urea-derived inorganic nitrogen was remained in the top zone between 0 and 10 cm depth of fertigated soil, while, most of the inorganic nitrogen (91%) was accumulated in the top zone of broadcast-applied soil. Of inorganic nitrogen derived from urea, the percentage of $NO_3{^-}$ was much higher for fertigation (99%) than for surface application (62%). The relatively lower recovery of urea-derived inorganic nitrogen of broadcast-applied urea-N (51%) than that of fertigated urea-N (89%) was attributable to enhanced $NH_3$ volatilization.

• Applied Chemistry for Engineering
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• v.27 no.1
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• pp.86-91
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• 2016

Three amorphous silicas and SBA-15 were employed as supports, which were capable of confining ionic liquid (IL) and metallocene in the nanopore. Ionic liquid functionalized silica was prepared by the interaction between the chloride anions of 1,3-bis(cyanomethyl)imidazolium chloride and the surface OH groups. Metallocene and methylaluminoxane (MAO) were subsequently immobilized on the ionic liquid functionalized silica for ethylene polymerization. The metallocene supported on ionic liquid functionalized XPO-2412 and XPO-2410 having a larger pore diameter compared to SBA-15 showed higher activity than that of using supported catalyst without ionic liquid functionalization. However, the activity of metallocene supported on SBA-15 decreased after ionic liquid functionalization, suggesting that the diffusion of ethylene monomer and cocatalyst to the active site of nanopore was restricted during ethylene polymerization. This could be resulted from significant reduction of the pore diameter due to the immobilization of ionic liquid and $(n-BuCp)_2ZrCl_2$ and MAO. The effect on polymerization activity in accordance with the concentration of hydroxyl groups on the surface was also investigated. The polymerization activity increased as the concentration of hydroxyl groups on amorphous silica increased. The polymerization activities of metallocene supported on silica showed the similar trend after ionic liquid functionalization.

• Journal of Life Science
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• v.27 no.1
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• pp.38-43
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• 2017

Glycosyl aesculin, a potent anti-inflammatory agent, was synthesized by transglycosylation reaction, catalyzed by Thermotoga neapolitana ${\beta}-glucosidase$, with aesculin as an acceptor. The key reaction parameters were optimized using response-surface methodology (RSM) and $2{\mu}g$ of the enzyme. As shown by a statistical analysis, a second-order polynomial model fitted well to the data (p<0.05). The response surface curve for the interaction between aesculin and other parameters revealed that the aesculin concentration and reaction time were the primary factors that affected the yield of glycosyl aesculin. Among the tested factors, the optimum values for glycosyl aesculin production were as follows: aesculin concentration of 9.5 g/l, temperature of $84^{\circ}C$, reaction time of 81 min, and pH of 8.2. Under these conditions, 61.7% of glycosyl aesculin was obtained, with a predicted yield of 5.86 g/l. The maximum amount of glycosyl aesculin was 6.02 g/l. Good agreement between the predicted and experimental results confirmed the validity of the RSM. The optimization of reaction conditions by RSM resulted in a 1.6-fold increase in the production of glycosyl aesculin as compared to the yield before optimization. These results indicate that RSM can be effectively used for process optimization in the synthesis of a variety of biologically active glycosides using bacterial glycosidases.

• Restorative Dentistry and Endodontics
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• v.33 no.5
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• pp.481-492
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• 2008

The purpose of this study is to observe and compare the remineralization tendencies of artificially demineralized enamel by remineralization solutions of different degree of saturations at pH 5.5, using a polarizing microscope and computer programs (Photoshop, Image pro plus, Scion Image, Excel). For this study, 36 sound permanent teeth with no signs of demineralization, cracks, or dental restorations were used. The specimens were immersed in lactic acid demineralization solution for 3 days in order to produce dental caries artificially that consist of surface and subsurface lesions. Each of 9 or 10 specimens was immersed in pH 5.5 lactic acid buffered remineralization solution of three different degrees of saturation (0.25, 0.30, 0.35) for 12 days. After the demineralization and remineralization, images were taken by a polarizing microscope $({\times}100)$. The results were obtained by observing images of the specimens, and using computer programs, the density of caries lesions were determined. In conclusion, in the group with the lowest degree of saturation, remineralization occurred thoroughly from the surface to the subsurface lesion, whereas in the groups with greater degree of saturation showed no significant change in the subsurface lesion, although there was corresponding increase in the remineralization width on the surface zones.

• Journal of the Korean Applied Science and Technology
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• v.36 no.1
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• pp.248-257
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• 2019

On this study, we have observed the change of the gel nail morphology as the time elapse and measured the surface roughness/volume, moisture content/purcutaneous moisture vaporizing amount of the nail surface before gel nail treatment and after gel nail removing of the 100%acetone remover, 5%acetone remover and 0%acetone remover and the avocado non acetone remover for the comparison of the effect on the nail surface and the degree of the removing of the gel nail of the removers as the acetone contents. The removing ability were the order of 100%acetone remover, avocado non acetone remover, 5%acetone remover and the 0%acetone remover. There were no statistical significance difference in the nail surface roughness comparision before and after gel nail removing in 5%acetone, 0%acetone and avocado non acetone, and there was no statistical significance difference in the nail surface volume comparision before and after gel nail removing in 0%acetone. We measured the moisture content of the nail surface and the purcutaneous moisture vaporizing amount before gel nail treatment and after gel nail removing, resulted that, the decrease of the moisture content of the nail surface after removing the gel nail is the minimun and the increase of the purcutaneous moisture vaporizing amount of the nail surface after removing the gel nail is the minimun at the case of 0%acetone. In conclusion, 5%acetone remover and 0%acetone remover is possible to use as the gel nail remover and they had revealed that there was the least harmful effect on the nail. We hope that this study is utilized to the development of the non acetone remover and the basic research of the nail beauty industry.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.4 no.1
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• pp.46-56
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• 1994

The characteristics of flows, temperatures, concentrations of the boron are numerically studied when uniform axial magnetic fields are applied in the Czechralski crucible. The to governing factors to the flow regimes are buoyancy, thermocapillarity, centrifugal forces, magnetic forces, diffusion coefficient and segregation coefficient of the boron. Since the concentration of the boron is so low that buoyancy effects are negligible, it cannot affect the flow and temperature fields. From the fact that the flow fields are rotationally symmetric, two velocity components in the meridional plane and the circumferential velocity are calculated together with the temperature in the steady state. Based on the known velocity and temperature distributions the unsteady concentration distributions of the boron are calculated. As the strength of the magnetic is increased, the flow velocities are decreased. Circumferential velocities are large near the crucible side-wall and in the region below the rotating crystal. Steep temperatures gradient near the edge of the rotating crystal causes the Marangoni convection. It has been found out that the convection characteristics affects the unsteady transport phenomena of the boron.

• KSBB Journal
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• v.9 no.3
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• pp.253-265
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• 1994

We have studied the effects of serum concentration and initial cell density on hybridoma cell growth and monoclonal antibody (MAb) production at various media supplemented with different types of serum. The types of serum were fetal bovine sera, newborn bovine calf sera, calf sera including supplemented calf sera, horse serum, and goat serum. The concentrations of each serum were 0.5, 1.25, 2.5, and 5% (v/v) and the inoculum densities were $5{\times}10^4, 1{\times}10^5, 2{\times}10^5,$ cells/ml. The hybridoma cell growth and anti-Hepatitis B surface antigen (anti-HBsAg) MAb production were found to be enhanced by increasing the serum concentration and by increasing inoculum density regardless of serum type. We found that test sera purchased from different companies show different effects on cell growth and MAb production, although they are the same type of serum.

• Applied Chemistry for Engineering
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• v.21 no.4
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• pp.475-478
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• 2010

Fluorinated polymeric membranes were prepared by direct surface modification of PDMS with fluorine gas ($50{\sim}2000\;{\mu}mol/mol$ in nitrogen). The formed fluorinated polymeric membranes were characterized by FT-IR spectroscopy, GC (Gas chromatography), atomic force microscopy, and scanning electron microscopy. Direct fluorination resulted in the change of permeability and selectivity of various gases (pure gases such as $CO_2$, $O_2$, $N_2$, $C_2H_4$, mixture of He, Ne, Kr, Xe) through PDMS membranes. Fluorination resulted in the maximum 50% increase of selectivity through PDMS membrane.

• Membrane Journal
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• v.23 no.6
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• pp.439-449
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• 2013

This study investigated the aromatic polyamide reverse osmosis membrane was modified with diphenylamine (DPA) for enhanced chlorine and fouling resistance and how to optimize. DPA has high reactivity and thermo chemical stability. The performance of a modified membranes was investigated and its surface analyzed using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and contact angle measurement. The experiment was conducted while changing the conditions of temperature and DPA solution concentration.