• The Korean Journal of Food And Nutrition
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• v.36 no.5
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• pp.403-414
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• 2023

This study aimed to determine the anti-obesity effect of adding Wolfiporia extensa Ginns (W) to fermented pollack skin products in an obesity-induced animal model. The experimental groups were the normal diet group (C), high-fat diet group (HF), dried pollack skin (H1), fermented pollack skin (H2), and W of 0.1 (F2-WL), 0.3 (F2-WM), and 0.5 (F2), respectively. It was confirmed that adding W to fermented pollack skin reduced blood triglycerides, total cholesterol, and LDL levels, while increasing HDL levels. Wolfiporia extensa Ginns was effective in controlling weight and improving blood lipids in a dose-dependent manner. In histological analysis, findings of fatty liver induced by a high-fat diet were improved by the addition of H2 and W. Size and density of fat globules in the epididymis were decreased. In addition, the concentration of TNF-α was increased in the high-fat diet group, but decreased by the addition of fermented pollack skin and W. In conclusion, adding fermented dried pollack skin and Wolfiporia extensa Ginns was effective for weight control and blood lipid improvement. Thus, the use of by-products in functional foods is expected to have a high value in the future.

• Asian Journal of Atmospheric Environment
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• v.8 no.1
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• pp.25-34
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• 2014

In winter 2013, extreme air pollution by fine particulate matter ($PM_{2.5}$) in China attracted much public attention. In order to simulate the $PM_{2.5}$ pollution, the Community Multiscale Air Quality model driven by the Weather Research and Forecasting model was applied to East Asia in a period from 1 January 2013 to 5 February 2013. The model generally reproduced $PM_{2.5}$ concentration in China with emission data in the year 2006. Therefore, the extreme $PM_{2.5}$ pollution seems to be mainly attributed to meteorological (weak wind and stable) conditions rather than emission increases in the past several years. The model well simulated temporal and spatial variations in $PM_{2.5}$ concentrations in Japan as well as China, indicating that the model well captured characteristics of the $PM_{2.5}$ pollutions in both areas on the windward and leeward sides in East Asia in the study period. In addition, contribution rates of four anthropogenic emission sectors (power generation, industrial, residential and transportation) in China to $PM_{2.5}$ concentration were estimated by conducting zero-out emission sensitivity runs. Among the four sectors, the residential sector had the highest contribution to $PM_{2.5}$ concentration. Therefore, the extreme $PM_{2.5}$ pollution may be also attributed to large emissions from combustion for heating in cold regions in China.

• Archives of Pharmacal Research
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• v.27 no.7
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• pp.806-810
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• 2004

Metformin is a biguanide antihyperglycemic agent often used for the treatment of non-insulin dependent diabetics (NIDDM). In this study, the pharmacokinetics and pharmacodynamics of metformin were investigated in Korean healthy volunteers during a fasting state for over 10 h. In order to evaluate the amount of glucose-lowering effect of metformin, the plasma concentrations of glucose were measured for a period of 10 h followed by the administration of metformin (oral 500 mg) or placebo. In addition, the concentration of metformin in blood samples was determined by HPLC assay for the drug. All volunteers were consumed with 12 g of white sugar 10 minutes after drug intake to maintain initial plasma glucose concentration. The time courses of the plasma concentration of metformin and the glucose-lowering effect were analyzed by nonlinear regression analysis. The estimated $C_{max}$, $T_{max}$, $CL_{t}$/F (apparent clearance), V/F(apparent volume of distribution), and half-life of metformin were 1.42$\{pm}$0.07 $\mu\textrm{g}$/mL, 2.59$\{pm}$0.18h, 66.12$\{pm}$4.6 L/h, 26.63 L, and 1.54 h respectively. Since a significant counterclock-wise hysteresis was found for the metformin concentration in the plasma-effect relationship, indirect response model was used to evaluate pharmacodynamic parameters for metformin. The mean concentration at half-maximum inhibition $IC_{50}$, $k_{in}$, $k_{out}$ were 2.26 $\mu\textrm{g}$/mL, 83.26 $H^{-1}$, and 0.68 $H^{-1}$, respectively. Therefore, the pharmacokinetic-pharmacodynamic model may be useful in the description for the relationship between plasma concentration of metformin and its glucose-lowering effect.

• Korean Chemical Engineering Research
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• v.46 no.2
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• pp.301-309
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• 2008

In this study, the effect of formaldehyde to phenol (F/P) molar ratios, catalyst wt%, and reaction temperature on the chemical structure was studied utilizing a two-level full factorial experimental design. The effect of three variables on the chemical structure was analyzed by using three-way ANOVA of SPSS. Concentration of methyrol-substituted phenols after 300 min addition reaction increased with higher the F/P mole ratio, lower the reaction temperature and lower the catalyst wt%. Resol catalysed by barium hydroxide showed higher addition of formaldehyde onto ortho positions of phenolic rings. A simplified elementary reaction model for resole type phenolic resin formation which do not consider the dissociation of phenolic compounds and the fraction of formaldehyde in the form of methylene glycol was proposed and compared with Zavitsas' type models. Elementary reaction model showed error of 2.79% compared to the error of 3.27% in Zavitsas' type models. It was thought that the elementary reaction model could be used to predict the behavior of addition reaction in resol formation.

• Nuclear Engineering and Technology
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• v.44 no.4
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• pp.369-378
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• 2012

A load-following operation in APR+ nuclear plants is necessary to reduce the need to adjust the boric acid concentration and to efficiently control the control rods for flexible operation. In particular, a disproportion in the axial flux distribution, which is normally caused by a load-following operation in a reactor core, causes xenon oscillation because the absorption cross-section of xenon is extremely large and its effects in a reactor are delayed by the iodine precursor. A model predictive control (MPC) method was used to design an automatic load-following controller for the integrated thermal power level and axial shape index (ASI) control for APR+ nuclear plants. Some tracking controllers employ the current tracking command only. On the other hand, the MPC can achieve better tracking performance because it considers future commands in addition to the current tracking command. The basic concept of the MPC is to solve an optimization problem for generating finite future control inputs at the current time and to implement as the current control input only the first control input among the solutions of the finite time steps. At the next time step, the procedure to solve the optimization problem is then repeated. The support vector regression (SVR) model that is used widely for function approximation problems is used to predict the future outputs based on previous inputs and outputs. In addition, a genetic algorithm is employed to minimize the objective function of a MPC control algorithm with multiple constraints. The power level and ASI are controlled by regulating the control banks and part-strength control banks together with an automatic adjustment of the boric acid concentration. The 3-dimensional MASTER code, which models APR+ nuclear plants, is interfaced to the proposed controller to confirm the performance of the controlling reactor power level and ASI. Numerical simulations showed that the proposed controller exhibits very fast tracking responses.

• Food Engineering Progress
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• v.15 no.1
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• pp.34-40
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• 2011

As an attempt to develop a value-added food product, purple sweet potato powder was added in a model system of steamed bread as a healthy food ingredient and physicochemical properties such as moisture content, specific volume, spread ratio, color, texture as well as consumer preferences on the attributes such as uniformity, color, flavor, elasticity, chewiness, taste, and overall preference were evaluated. Moisture content ranged from 44.16 to 44.55% (wet basis) and appeared independent on the level of purple sweet potato (PSP) powder incorporation. As a result of the addition of PSP powder, the specific volume of steamed bread decreased from 3.22 to 2.55 mL/g, and value of 4.5% sample was significantly lower than other samples (p<0.05). On the other hand, spread ratio ranged from 2.01 to 2.53, and appeared to decrease as the PSP powder concentration increased (p<0.05), indicating a significant improvement. Lightness $(L^*)$ decreased significantly as the PSP powder content increased (p<0.05) for both dough and skin of the steamed bread. In addition, an increasing trend in redness ($a^*$-value) and a decreasing trend in yellowness ($b^*$-value) were noticed. Firmness increased significantly with the addition of PSP powder regardless of concentration (p <0.05); however, firmness was not significantly different among samples containing 1.5-4.5% PSP powder (p>0.05). Consumer acceptance test indicated that incorporation of 3% PSP powder in the formulation of steamed breads would be recommended.

• Particle and aerosol research
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• v.6 no.4
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• pp.151-164
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• 2010

Inorganic ions and water are major components of ambient fine particles. Water content in fine particles is mainly determined by ambient meteorological conditions and the concentrations of hygroscopic species such as inorganic ions. Thus, to reduce fine particle mass concentration, it is important to accurately estimate the relationship between water content and the concentration of ions in fine particles. Water content in fine particles in Seoul are estimated by using a gas/particle equilibrium model to understand the characteristics of fine particle mass concentration. In addition, sensitivity of fine particle mass concentration to the changes of particulate ionic species (sulfate, nitrate, and ammonium) is estimated. It was found that water content in Seoul is mostly determined by the concentrations of the hygroscopic ionic species, especially, sulfate and ammonium, and ambient relative humidity.

• Advances in environmental research
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• v.1 no.2
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• pp.153-166
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• 2012

Decolourization potential of white rot fungal organism, coriolus versicolor, was investigated in a batch reactor, for textile dye industry wastewater. The influence of process parameters like pH, temperature, agitation speed and dye wastewater concentration on the decolourization of textile dye wastewater was examined by using Response surface methodology (RSM). The maximum decolourization was attained at: pH- 6.8, temperature - $27.9^{\circ}C$, agitation speed - 160 rpm and dye wastewater concentration - 1:2. From the analysis of variance (ANOVA) results it was found that, the linear effect of agitation speed and dye wastewater concentration were significant for the decolourization of textile dye wastewater. At these optimized condition, the maximum decolourization and chemical oxygen demand (COD) reduction was found to be 64.4% and 79.8% respectively. Various external carbon sources were tried to enhance the decolourization of textile dye wastewater. It was observed that the addition of carbon source enhances the decolourization of textile dye wastewater. Kinetics of textile dye degradation process was studied by first order and diffusional model. From the results it was found that the degradation follows first order model with $R^2$ value of 0.9430.

• Environmental Engineering Research
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• v.23 no.4
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• pp.374-382
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• 2018

Petroleum hydrocarbons pollutants, such as diesel fuel, have caused ecosystem damage in terrestrial and aquatic habitats. They have been recognized as one of the most hazardous wastes. This study was designed to optimize the effect of Tween 80 concentration, nitrogen (N)/phosphorus (P) ratio and salinity level on diesel biodegradation by Vibrio alginolyticus (V. alginolyticus). Response surface methodology with Box-Behnken design was selected with three factors of Tween 80 concentration (0, 5, 10 mg/L), N/P ratio (5, 10, 15) and salinity level (15‰, 17.5‰, 20‰) as independent variables. The percentage of diesel degradation was a dependent variable for 14 d of the remediation period. The results showed that the percentages of diesel degradation generally increased with an increase in the amount of Tween 80 concentration, N/P ratio and salinity level, respectively. The optimization condition for diesel degradation by V. alginolyticus occurred at 9.33 mg/L of Tween 80, 9.04 of N/P ratio and 19.47‰ of salinity level, respectively, with percentages of diesel degradation at 98.20%. The statistical analyses of the experimental results and model predictions ($R^2=0.9936$) showed the reliability of the regression model and indicated that the addition of biostimulant can enhance the percentage of diesel biodegradation.

• Geomechanics and Engineering
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• v.28 no.2
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• pp.135-143
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• 2022

Soils are natural granular materials whose mechanical properties differ according to the size and composition of the particles, so soils exhibit an obvious scale effect. Traditional soil mechanics is based on continuum mechanics, which can not reflect the impact of particle size on soil mechanics. On that basis, a matrix-reinforcing-particle cell model is established in which the reinforcing particles are larger-diameter sand particles and the matrix comprises smaller-diameter bentonite particles. Since these two types of particles deform differently under shear stress, a new shear-strength theory under direct shear that considers the stress concentration and bypass phenomena of the matrix is established. In order to verify the rationality of this theory, a series of direct shear tests with different reinforcing particle diameter and volume fraction ratio are carried out. Theoretical analysis and experimental results showed that the interaction among particles of differing size and composition is the basic reason for the size effect of soils. Furthermore, the stress concentration and bypass phenomena of the matrix enhance the shear strength of a soil, and the volume ratio of reinforcing particles has an obvious impact on the shear strength. In addition, the newly proposed shear-strength theory agrees well with experimental values.