• Journal of Life Science
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• v.17 no.1 s.81
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• pp.31-38
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• 2007

Infection with virulent or attenuated Salmonella typhimuriumhas known to induce reduction in proliferative responses of spleen cells. We investigated a role of lipid A from S. typhimurium, a B cell mitogen, on proliferation of spleen cells by T cell mitogens such as concanavaline A and phytohemagglutinin under in vitro and ex vivo conditions. Lipid A alone induced proliferation of spleen cells in vitroin a dose-dependent manner. However, subsequent treatment of concanavaline A or phytohemagglutin in after lipid A treatment induced proliferation suppression of murine spleen cells in vitro and ex vivo. Removal of macrophages from spleen cells, which were obtained from a lipid A-injected mouse, restored proliferation by concanavaline A and phytohemagglutinin, indicating that macrophages appeared to play a role in lipid A-induced suppression. Secreted molecules from macrophages did not accounted for the suppression because suppressive effect was not achieved when the supernatant from macrophage-containing spleen cell culture was conditoned to macrophage-depleted spleen cell culture. Co-culture of spleen cells from lipid A-treated and - untreated mice showed proliferation suppression as increasing cell numbers of lipid A-treated mouse. These data suggested that the cell-to-cell contact of macrophage with splenic lymphocyte cells is responsible for immune responses against lipid A, which is applicable to the case of human S. typhi infection.

• Journal of the Korea Concrete Institute
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• v.29 no.1
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• pp.101-107
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• 2017

This study aimed to conduct the basic analysis on the fractal characteristics of cementitious materials. The pore structure of cement paste incorporating ground granulated blast furnace slag (GGBFS) was measured using mercury intrusion porosimetry (MIP) and the fractal characteristics were investigated using different models. Because the pore structure of GGBFS-blended cement paste is an irregular system in the various range from nanometer to millimeter, the characteristics of pore region in the different scale may not be adequately described when the fractal dimension was calculated over the whole scale range. While Zhang and Li model enabled analyzing the fraction dimension of pore structure over the three divided scale ranges of micro, small capillary and macro regions, Ji el al. model refined analysis on the fractal characteristics of micro pore region consisting of micro I region corresponding to gel pores and micro II region corresponding to small capillary pores. As the pore size decreased, both models suggested that the pore surface of micro region became more irregular than macro region and the complexity of pores increased.

• Transactions of the KSME C: Technology and Education
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• v.3 no.1
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• pp.23-28
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• 2015

In this paper, we performed the design optimization dual-shell and tube heat exchanger on exhaust waste heat recovery for gas heat pump using CFD and RSM. CFD analysis is useful to design the complex structure such as double shell and tube heat exchanger. By computer simulation, engineers can assess the feasibility of the given design factors and change them to get a better design. But if one wishes to perform complex analysis on the simulation, such dual-shell and tube heat exchanger for GHP, the computational time can become overwhelming. CFD is powerful but it takes a lot of time for complex structure. Therefore, the CFD analysis is minimized by the optimization using the RSM method. As a result, the number of baffle and tube are optimized by 6 baffles and 25 tubes for heat transfer and flow friction. And then pressure drop and heat transfer is improved about 12.2%. We confirm the design optimization using CFD and RSM is useful on complex structure of heat exchanger.

• Food Science and Preservation
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• v.22 no.1
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• pp.1-11
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• 2015

Raspberries are a good resource of polyphenols and have a powerful antioxidant activity, but shelf life for raspberries is short which brings a lot of economic losses. In this study, we try to use cool-air ($20{\sim}40^{\circ}C$) or hot-air ($60{\sim}100^{\circ}C$) to produce semi-dried raspberries with extended shelf life, and to determine the best method for improving fruit quality by minimizing nutrient losses during drying processes. The effects of process variables (drying temperature and processing time) on the quality of final dried raspberries were investigated. Response surface methodology was employed to establish statistical models for simulating the drying processes, and the moisture residue content and the loss ratios of total phenolic content (TPC), vitamin C (VC), and ellagic acid (EA) that result from the drying processes of raspberries using either hot or cool-air were predicted. Superimposed contour plots have been successfully used in the determination of the optimum zone within the experimental region. Optimal conditions determined for achieving minimal losses of TPC, VC, and EA, and a final moisture residue of 45% using the hot-air drying process were a drying temperature of $65.75^{\circ}C$ and a processing time of 4.3 hr. While for the cool-air process, the optimal conditions predicted were $21.3^{\circ}C$ and 28.2 hr. Successful application of response surface methodology provided scientific reference for optimal conditions of semi-drying raspberries, minimizing nutrient losses and improving product quality.

• Journal of the Korean GEO-environmental Society
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• v.12 no.4
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• pp.25-31
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• 2011

In this study, the experimental design methodology was applied to optimize 1,4-dioxane treatment in E-beam process. Main factor was mathematically described as a function of parameters 1,4-dioxane removal efficiencies(%), TOC removal efficiencies(%) modeled by the use of the central composite design(CCD) method among the response surface methodology(RSM). Concentration of 1,4-dioxane is designated as "$x_1$" and Irradiation intensity is designated as "$x_2$". The regression equation in coded unit between the 1,4-dioxane concentration and removal efficiencies(%) was $y=71.00-10.85x_1+20.67x_2+{1.53x_1}^2-{7.92x_2}^2-1.23x_1x_2$. The regression equation in coded unit between the 1,4-dioxane concentration and TOC removal efficiencies(%) was $y=44.48-13.25x_1+9.54x_2+{5.43x_1}^2-{1.35x_2}^2+4.45x_1x_2$. The model predictions agreed well with the experimentally observed results $R^2$(Adj) over 90%. Toxicity test using algae Pseudokirchneriella Subcapitata showed that the inhibition was reduced according to increasing an E-beam irradiation.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.48 no.3
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• pp.255-264
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• 2022

The active ingredients of Napttegi Kong(GML, Glycine max landrace), a type of native rare soybeans, were identified, and an ultrasonic extraction method was introduced as an eco-friendly extraction method. Through the component analysis of the Napttegi Kong extract, the epicatechin, which was not found in conventional soybeans, was identified. For effective extraction using ultrasonic, the main extraction conditions were optimized using the response surface analysis method. Through the Box-Behnken design process, 15 experiments were conducted with the extraction temperature, the ratio of extraction solvent/solution, and extraction time as key independent variables. A quadratic regression equation for the two dependent variables, epicatechin content and total isoflavone content, was derived, and the coefficients of determination were found to be high as R² = 0.9939 and R² = 0.9844, respectively, confirming that the correlation showed high significance. The extraction conditions satisfying the maximum expectations of these two dependent variables were predicted. to be 40.4℃ of extraction temperature, 19.3 times of extraction solvent/solution, and 91 sec of extraction time. The expected value and the actual experimental value of the epikatechin content and the total isoflavone content were similar, so it was confirmed that this experimental method is a highly reliable optimization model.

• KIPS Transactions on Software and Data Engineering
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• v.11 no.8
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• pp.331-338
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• 2022

Successor representation (SR) is a model of human reinforcement learning (RL) mimicking the underlying mechanism of hippocampal cells constructing cognitive maps. SR utilizes these learned features to adaptively respond to the frequent reward changes. In this paper, we evaluated the performance of SR under the context where changes in latent variables of environments trigger the reward structure changes. For a benchmark test, we adopted SR-Dyna, an integration of SR into goal-driven Dyna RL algorithm in the 2-stage Markov Decision Task (MDT) in which we can intentionally manipulate the latent variables - state transition uncertainty and goal-condition. To precisely investigate the characteristics of SR, we conducted the experiments while controlling each latent variable that affects the changes in reward structure. Evaluation results showed that SR-Dyna could learn to respond to the reward changes in relation to the changes in latent variables, but could not learn rapidly in that situation. This brings about the necessity to build more robust RL models that can rapidly learn to respond to the frequent changes in the environment in which latent variables and reward structure change at the same time.

• Journal of the Korean Society of Radiology
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• v.11 no.5
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• pp.361-370
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• 2017

In the Brain MRI, RF Pulse is irradiated on the human body in order to acquire an image. At this time, a considerable part of the irradiated RF Pulse energy is absorbed as it is in our body. This will raise the temperature of the human body, but depending on the extent of exposure, it will affect the human body. The change of the SAR and the temperature of the head according to the change of the magnetic field strength is examined. And to investigate the difference in results depending on the use of dental implant. In the human head model, 64 MHz RF Pulse frequency generated from 1.5 T, 128 MHz RF Pulse frequency generated from 3.0 T, and 298 MHz RF Pulse frequency generated from 7.0 T send a frequency and experiment was performed using dental implant using the XFDTD program, we measured the SAR and body temperature changes around the head. The SAR value showed up to about 5800 times the difference at the RF Pulse frequency of 256 MHz, when with dental implant than without dental implant and as the frequency increased, the use of the dental implant increased difference in the SAR value. The change of the temperature of the head showed a temperature rise nearly 2 to 4 times when with dental implant than without dental implant. As the RF Pulse frequency increase, the SAR value increase, but the change of the temperature of the head decrease. Because of as the frequency increase, wavelength is smaller and the more the amount absorbed by the surface of the human. Physiological and biochemical studies of the human body ar necessary through studies of the presence of dental implant and the cause of reaction caused by change in the RF Pulse frequency.

• Food Science and Preservation
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• v.30 no.5
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• pp.857-867
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• 2023

In this study, the extraction yield, acidic polysaccharides and ginsenosides of red and black ginseng were optimized by using the response surface methodology in consideration of the ethanol concentration and temperature of the extraction. The R² of the model formula for the yield, acidic polysaccharides and ginsenosides was 0.8378-0.9679 (p<0.1). An optimal extraction yield of 5.29% was reached for red ginseng soluble solids when 1.52% ethanol concentration was used at a temperature of 67.27℃. Additionally, the optimal extraction yield for black ginseng soluble solid was 6.11% when 3.12% ethanol concentration was used at a temperature of 66.13℃. Furthermore, the optimal conditions for extracting acidic polysaccharides from red ginseng were using an ethanol concentration of 4.03% at a temperature of 69.61℃; a yield of 1.86 mg/mL was obtained. The optimal extraction yield for acidic polysaccharides from black ginseng was 1.80 mg/mL when extracted using a concentration of 24.67% of ethanol at a temperature of 71.14℃. An optimal extraction yield of 0.22 mg/mL was reached for ginsenoside Rg₁ from red ginseng when 79.92% ethanol concentration was used at a temperature of 70.62℃. The optimal extraction yield of ginsenoside Rg₃ from black ginseng was 0.31 mg/mL when ethanol was used at a concentration of 75.70% at a temperature of 65.49℃. The ideal extraction conditions for obtaining the maximum yield of both acidic polysaccharide and ginsenoside from red and black ginseng were using ethanol at a concentration between 35 and 50% at an extraction temperature of 70℃.

• Journal of the Korean GEO-environmental Society
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• v.15 no.1
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• pp.63-68
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• 2014

In this study, it was found that determined the photocatalytic degradation of antibiotics (lincomycin, LM) with various catalyst composite of titanium dioxide ($TiO_2$), hydroxyapatite (HAP) and germanium (Ge) under UV-A irradiation. At first, various type of complex catalysts were investigated to compare the enhanced photocatalytic potential. It was observed that in order to obtain the removal efficiencies were $TiO_2/HAP/Ge$ > $TiO_2/Ge$ > $TiO_2/HAP$. The composition of $TiO_2/HAP/Ge$ using a statistical approach based on mixture analysis design, one of response surface method was investigated. The independent variables of $TiO_2$ ($X_1$), HAP ($X_2$) and Ge ($X_3$) which consisted of 6 condition in each variables was set up to determine the effects on LM ($Y_1$) and TOC ($Y_2$) degradation. Regression analysis on analysis of variance (ANOVA) showed significant p-value (p < 0.05) and high coefficients for determination value ($R^2$ of $Y_1=99.28%$ and $R^2$ of $Y_2=98.91%$). Contour plot and response curve showed that the effects of $TiO_2/HAP/Ge$ composition for LM degradation under UV-A irradiation. And the estimated optimal composition for TOC removal ($Y_2$) were $X_1=0.6913$, $X_2=0.2313$ and $X_3=0.0756$ by coded value. By comparison with actual applications, the experimental results were found to be in good agreement with the model's predictions, with mean results for LM and TOC removal of 99.2% and 49.3%, respectively.