• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.4
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• pp.743-750
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• 1997

Direct measurement of the kinetics of free fatty acid transfer between phospholipid model membrane is technically limited by the rapid nature of the transfer process. Separation of membrane-bound fatty acid by centrifugation has shown that although the equilibrium distribution of free fatty acid is determined by this method, fatty acid transfer occurs too rapidly for accurate kinetic measurements. Recently fluorescence resonance energy transfer(FRET) assay has been developed to examine transfer of fatty acids between membranes. Donor membranes which has fluorescent fatty acid, anthroyloxy fatty acid(AOFA), is mixed with acceptor membranes which has non-interchangeable fluorescent quencher, nitrobenzo-xadiazol(NBD), using stopped flow apparatus. As the fluorescent fatty acids transfer from donor membrane to acceptor membrane, fluorescence intensity would be decreased and the rate and degree of fatty acid transfer can be analyzed. Fatty acid transfer between micelles is more complicated because of bile salt. Therefore in experiments with micelles, fluorescence self quenching assay is used. At high concentrations, a fluorophore tends to quench its own fluorescence causing a reduction in fluorescence intensity. Donor micelles contained self quenching concentrations of fluorophore and acceptor micelles had no fluorophore. Upon mixing of donor and acceptor micelles, the rate of transfer of the fluorophore from the donor to the acceptor was measured by monitoring the release in self quenching when its concentration in donor decreased over time.

• Korean Journal of Clinical Pharmacy
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• v.9 no.1
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• pp.49-54
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• 1999

This study was carried out to compare the bioavailability of Hanmi clarithromycin (250 mg/tablet) with that of $Klaricid^{(R)}$ The bioavailability was examined on 20 volunteers who received a single dose (500 mg) of each drug in the fasting state in a randomized balanced 2-way crossover design. After dosing, blood samples were collected for a period of 12 hours. Plasma samples were analyzed for clarithromycin and roxithromycin(internal standard) by HPLC/Coulometric BCD. The pharmaco-kinetic parameters ($AUC_{0-l2hr}$, Cmax, Tmax, $AUC_{inf}$, Ka, Kel, $t_{1/2}$, Vd/F and Cl/F) were calculated from the plasma clarithromycin concentration-time data of each volunteer. The computer program 'WinNonlin' was used for compartmental analysis. One compartment model with first-order input, from order output with lag time, weighting factor $l/y^2$ was chosen as the appropriate pharmacokinetic model. The major pharmacokinetic parameters ($AUC_{0-l2hr},\;AUC_{inf}$, Cmax and Tmax) of Hanmi clarithromycin were $10.7\pm0.5\;{\mu}g{\cdot}hr{\cdot}ml^{-1},\;12.7\pm0.7\;{\mu}g{\cdot}hr{\cdot}ml^{-1},\;1.7\pm0.1\;{\mu}g/ml\;and\;2.0\pm0.2\;hr$, respectively, and those of $Klaricid^{(R)}\;were\;9.8\pm0.5\;{\mu}g{\cdot}hr{\cdot}ml^{-1},\;11.7\pm0.6\;{\mu}g{\cdot}hr{\cdot}ml^{-1},\;1.6\pm0.1\;{\mu}g/ml\;and\;2.1\pm0.1\;hr$, respectively. The differences in mean values of $AUC_{0-l2hr},\;AUC_{inf}$ and Cmax between two products were $9.88\%,\;8.94%\;and\;6.59\%$, respectively. The least significant differences at $\alpha=0.05$ for $AUC_{0-l2hr},\;AUC_{inf}$ and Cmax were $16.08\%,\;17.81\%\;and\;18.94\%$, respectively. Though the plasma clarithromycin concentrations of Hanmi clarithromycin were higher than those of $Klaricid^{(R)}$ at all observed times, the bioavailability of Hanmi clarithromycin appeared to be bioequivalent with that of $Klaricid^{(R)}$. The Ka, Kel, $t_{1/2}$, Vd/F and Cl/F of the Hanmi clarithromycin were $2.69\pm0.53\;hr^{-1},\;0.18\pm0.01 hr^{-1},\;3.9\;hr,\;248.8\pm11.4\;L\;and\;43.7\pm2.6\;L/hr$, respectively, and those of $Klaricid^{(R)} were 2.19\pm0.51\;hr^{-1},\;0.18\pm0.02\;hr^{-1},\;3.7\;hr,\;266.7\pm22.4\;L\;and\;45.3\pm2.8L/hr$, respectively. There were no statistically significant differences between two drugs in all pharmacokinetic parameters.

• Food Engineering Progress
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• v.13 no.2
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• pp.138-146
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• 2009

The crude polysaccharide fraction from fruit body of Auricularia auricula were obtained by using hot water extraction and ethanol precipitation. As the crude polysaccharide fraction contained the brownish dark colored compounds, the adsorption study of pigments from the crude polysaccharide using activated carbon was carried out. The pigment compounds showed an absorption characteristic with $\lambda_{max}$ of 230 nm and the absorbance at 230 nm was taken as color intensity. Adsorption capacity of pigment depended on increase of the activated carbon to sample loading ratio. The adsorption capacity increased with increase of pH and temperature in the pH range of 3.0-7.0 and temperature range of 25-40$^{\circ}C$, but decreased in the temperature range of 40-70$^{\circ}C$. The optimum capacity was obtained at addition of 16.7 mg activated carbon per mL sample solution (concentration = 3 mg/mL) at pH of 7.0 and temperature of 40$^{\circ}C$. Treatment for 10 min was sufficient to achieve the 80% decolorization and 1.25 fold purification of polysaccharide. Langmuir isotherm and pseudo second-order kinetic model provided the best fitting for adsorption of the brownish dark colored compounds onto powdered active carbon. The activation energies of adsorption from the Langmuir isotherm parameter in the ranges of 25-40$^{\circ}C$ and 40-70$^{\circ}C$ was -2.54 and 4.38 kcal/g, respectively. The results of low activation energy also indicated that the adsorption process was a physical adsorption which was controlled by diffnsion.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.5
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• pp.333-340
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• 2019

Tests using a middle velocity propulsion impact machine (MVPIM) were performed to verify the impact resistance capability of sandwich concrete panels (SCP) in a modular liquefied natural gas (LNG) outer tank, and numerical models were constructed and analyzed. $2{\times}2m$ specimens with plain sectional characteristics and specimens including a joint section were used. A 51 kg missile was accelerated above 45 m/s and impacted to have the design code kinetic energy. Impact tests were performed twice according to the design code and once for the doubled impact speed. The numerical models for simulating impact behaviors were created by LS-DYNA. The external steel plate and filled concrete of the panel were modeled as solid elements, the studs as beam elements, and the steel plates as elasto-plastic material with fractures; the CSCM material model was used for concrete. The front plate deformations demonstrated good agreement with those of other tests. However the rear plate deformations were less. In the doubled speed test for the plain section specimen, the missile punctured both plates; however, the front plate was only fractured in the numerical analysis. The impact energy of the missile was transferred to the filled concrete in the numerical analysis.

• Journal of the Korean Society of Radiology
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• v.13 no.5
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• pp.791-799
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• 2019

We evaluated the physical properties that occur to dose enhancement and changes from secondary particle production resulting from the interaction between enhancement material. Geant4 was used to perform a Monte Carlo simulation, and the medical internal radiation dose (MIRD) head phantom were employed. X-rays of 4, 6, 10, 15, 18, and 25 MV were used. Aurum (Au) and gadolinium (Gd) were applied within the tumor volume at 10, 20, and 30 mg/g, and an experiment using soft tissue exclusively was concomitantly performed for comparison. Also, particle fluence and initial kinetic energy of secondary particle of interaction were measured to calculate equivalent doses using the radiation weight factor. The properties of physical interaction by the radiation enhancement material showed the great increased in photoelectric effect as compared to the compton scattering and pair production, occurred with the highest, in aurum and gadolinium it is shown in common. The photonuclear effect frequency increased as the energy increased, thereby increasing secondary particle production, including alpha particles, protons, and neutrons. During dose enhancement using aurum, a maximum 424.25-fold increase in the equivalent dose due to neutrons was observed. This study was Monte Carlo simulation corresponds to the physical process of energy transmission in dose enhancement. Its results may be used as a basis for future in vivo and in vitro experiments aiming to improve effects of dose enhancement.

• Clinical and Experimental Reproductive Medicine
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• v.44 no.3
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• pp.132-140
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• 2017

Objective: Correlations between semen parameters and sperm DNA fragmentation index (DFI) were investigated to identify characteristics of sperm without DNA damage that could be used in selecting sperm for intracytoplasmic sperm injection (ICSI). Pregnancy outcomes were compared to determine whether in vitro fertilization (IVF) or ICSI is a better choice for patients who have sperm with a high-DFI. Methods: Semen analysis was carried out in 388 patients who visited our IVF center for the first time to investigate correlations between sperm DFI and semen parameters. In addition, 1,102 IVF cycles in 867 patients were carried out in the present study; 921 cycles in the low-DFI group (DFI < 30%) and 181 cycles in the high-DFI group ($DFI{\geq}30%$). Both the low- and high-DFI groups were subdivided into IVF and ICSI cycle groups. Results: Sperm DFI showed significant inverse correlations with sperm motility (r = -0.435, p< 0.001) and morphology (r = -0.153, p< 0.05). Sperm DFI also showed significant correlations with rapid motility (r = -0.436, p< 0.001), and the kinetic parameters of average-path velocity (r = -0.403) and linearity (r = -0.412). Although there was no significant difference in the pregnancy rates between IVF (48.6%) and ICSI (44.8%) in the low-DFI group, the pregnancy rate of ICSI cycles (44.8%, p< 0.05) was significantly higher than IVF cycles (25.0%) in the high-DFI group. No significant difference was observed in the abortion rates between the low-DFI (52 of 921, 5.6%) and high-DFI groups (7 of 181, 3.8%). Conclusion: ICSI is a better choice than IVF for improving the pregnancy outcomes of patients who have sperm with a high DFI.

• Journal of Adhesion and Interface
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• v.15 no.1
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• pp.22-30
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• 2014

Self-photoinitiating acrylate (SPIA) which can undergo self-initiation under UV irradiation was synthesized by a Michael addition in the presence of a base catalyst. The SPIA polymerizations were investigated by photo-differential scanning calorimeter (photo-DSC) and surface physical properties such as pendulum hardness and pencil hardness. The results showed that the SPIA can cure upon UV irradiation by itself without a photoinitiator. But we found out that both the curing rate and the conversion were too low for the self-curing reaction of SPIA. In order to improve the SPIA curing properties, we introduced the SPIA/cationic hybrid system and observed the effects of the addition of commercial free radical type monomer and photoinitiator on the curing behaviors. SPIA/cationic hybrid system was the best suitable to improve the SPIA curing properties. The kinetic analysis indicated that the cationic monomer and photoinitiator apparently accelerated the cure reaction and rate of the hybrid SPIA system, mostly due to the synergistic effect of cationic monomer and photoinitiator increasing the mobility of active species and the generation of reactive species (free radical, cation) during the photopolymerization process. The physical properties showed that, unlike typical free radical system, the hybrid systems did not show oxygen inhibition effect because of cationic reaction on the coating surface.

• Nuclear Engineering and Technology
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• v.22 no.1
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• pp.20-28
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• 1990

In this study the migration experiment using packed column with crushed tuff was conducted as a basic research to develop migration model of radionuclides through geologic media. The main emphasis was put on evaluating the validity of migration models. For this, two models were introduced: one is the model which is based on the assumption of instantaneous equilibrium reaction and the other the model based on kinetic process such as intraparticle diffusion. The coefficient of hydrodynamic dispersion in packed column was determined using iodine as nonsorbing tracer. The hydrodynamic dispersion coefficient, D$_{L}$ was shown to be 0.11$\times$10$^{-2}$ $\textrm{cm}^2$/min under the condition of the column porosity of 0.483 and the average water velocity of 0.915$\times$10$^{-2}$ cm/min. The distribution coefficient, Kd of Cs-137 on crushed tuff was 11.3 cc/g at the concentration of 2$\times$10$^{-6}$ M and the temperature of 2$0^{\circ}C$. The breakthrough curve of Cs-137 through packed column was shown to have an asymmetric curve in which long trailing tail appears at the end part of the curve. The results obtained from the comparison of introduced models with experimental data indicated that the mass transfer model with intraparticle diffusion as rate-controlling step simulated the behaviors of Cs-137 migration more adequately, when compared with the bulk reaction model in which the assumption of instantaneous equilibrium reaction was maded. Consequently, the intraparticle diffusion was found to be an important factor in the migration of Cs-137 through packed column.n.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.977-982
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• 2011

This study was conducted to redetermine the rainfall erosion factor (R factor) in USLE for the estimation of soil loss at Korea. The redetermined R factor may be applied more precisely to interpret the changes of regional/yearly/seasonal patterns, including the amount of rainfall and the kinetic energy of rainfall, in Korea. This study calculated the R factors based on 60-minute precipitation data from 60 sites covering the whole country for 30 years from 1981 to 2010. As a result, the annual mean rainfall was $4,147MJ\;mm\;ha^{-1}\;yr^{-1}\;hr^{-1}$ in Korea. Coastal regions of Jeonnam and Gyeongnam, northwest regions of Gyeonggi, and Seoul had the greater values of R factor compared to other regions. The annual mean R factors for every decade were 3,988, 4,085, and $4,370MJ\;mm\;ha^{-1}\;yr^{-1}\;hr^{-1}$ in 1981~1990, 1991~2000, and 2001~2010, respectively. Generally, the R factors had an increasing tendency over and over pest decades. The ratios of summer R factor to total annual mean R factor were 69.8% (1981~1990), 73.7% (1991~2000), and 74.2% (2001~2010). We found that the absolute values and the relative ratios of summer rainfall are gradually increased.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.5
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• pp.377-382
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• 2007

Porous mineral coating have been fabricated and applied for basic research on their slow release action to a fertilizer. Feldspar was selected as raw mineral for the coating and two different particle sizes of powder were prepared. Slow-release action was estimated by using a potassium sulfate fertilizer. Spherical pellets were prepared with a pan-type pelletizer and then screened into sizes ranging 1.4 to 2.35mm. While the fertilizer pellets were rotated in the pelletizer again, the feldspar powder and 0.5% polyvinyl alcohol solution were simultaneously sprayed on the pellets. The fertilizer pellets coated with feldspar powder were fabricated. The pellets were heated to increase their strength and screened to sort by coating thickness. Potassium releasing tests were conducted for 40 days and the performance for slow-release action was estimated as functions of the heating temperature, coating thickness and raw mineral powder size. The Burst effect caused high initial releasing rate. Releasing kinetics was proportional to concentration of potassium in pellets. The pellet that was fabricated with $27.4{\mu}m$-sized feldspar and heated at $1050^{\circ}C$ showed a releasing rate of 43% on the 40th day.