• Journal of Nutrition and Health
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• v.53 no.3
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• pp.231-243
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• 2020

Purpose: To determine the metabolic influence of the traditional Korean diet (K-diet), which has been regarded as a healthy diet, we investigated the profile of urine organic acids that are intermediates of various types of metabolism including energy metabolism. Methods: Ten women aged 50-60 years were recruited and randomly divided into 2 diet groups, K-diet and control diet, the latter of which is a Westernized Korean diet that is commonly consumed by Koreans nowadays. Before and after the 2-week intervention, 46 urine organic acids were determined using LC/MS/MS, along with clinical parameters. Results: The average concentrations of succinate (4.14 ± 0.84 ㎍/mg creatinine vs. 1.49 ± 0.11, p = 0.0346) and hydroxymethylglutarate (3.67 ± 0.36 ㎍/mg creatinine vs. 2.97 ± 0.29, p = 0.0466), both of which are intermediates of energy metabolism, decreased in the K-diet group after the 2-week intervention, but these were not observed in the control diet group. In particular, the average concentration of succinate in the K-diet group was lower than that in the control group (3.33 ± 0.56 ㎍/mg creatinine vs. 1.49 ± 0.11, p = 0.0284) after 2 weeks. The concentrations of two tryptophan metabolites, 5-hydroxyindolacetate (3.72 ± 0.22 ㎍/mg creatinine vs. 3.14 ± 0.21, p = 0.0183) and indican (76.99 ± 8.35 ㎍/mg creatinine vs. 37.89 ± 10.06, p = 0.0205) also decreased only in the K-diet group. After the 2-week intervention, the concentration of kynurenate, another tryptophan metabolite, was lower in the K-diet group than that in the control diet group (3.96 ± 0.51 ㎍/mg creatinine vs. 2.90 ± 0.22, p = 0.0356). Interestingly, the urine level of kynurenate was positively correlated with BMI (r = 0.61424, p = 0.0003) and total cholesterol (r = 0.46979, p = 0.0088), which decreased only in the K-diet group (239.40 ± 15.14 mg/dL vs. 198.20 ± 13.25, p = 0.0163). Conclusion: The K-diet alters the urinary excretion of organic acids involved in energy metabolism and tryptophan metabolism, suggesting the influence of the K-diet on these types of metabolism. Urine organic acids changed by the K-diet may serve as biomarkers in future studies.

• Journal of Food Hygiene and Safety
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• v.34 no.6
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• pp.583-590
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• 2019

As the consumption of fresh fruits and vegetables increases, food poisoning caused by foodborne pathogen contamination is not decreasing. To prevent the contamination of produce, a quick and easy, low-cost, environmentally-safe disinfection method that does not affect produce freshness or quality is needed. This study demonstrates a new-concept, circulating-water disinfection system that purifies water by using newly developed 'LED-PS (photosensitizer)-induced ROS generation unit'. Using various types of LED-PS induced ROS generation units, we investigated the conditions for reducing the density of various pathogenic bacteria by more than 3 log CFU / mL in 1 hour. The major operational factors affecting the density reduction of the LED-PS-induced ROS generation unit were analyzed. Depending on bacteria species, the density reduction rate was varied. The effect of the units on reducing the density of Bacillus cereus and Pectobacterium carotovorum subsp. carotovorum was high, but the effect on foodborne bacteria such as Escherichia coli was relatively low. In this circulating water disinfection system, the density reduction effect tended to increase as the flow rate increased and the initial bacterial density decreased. As the amount of PS absorbed beads increased, the density reduction effect increased exponentially in some bacteria. Model 3280, a double cylindrical unit connecting two single cylindrical units, could completely sterilize more than 3 log CFU/mL of B. cereus and P. carotovorum subsp. carotovorum in 30 minutes of LED irradiation.

• Microbiology and Biotechnology Letters
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• v.37 no.2
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• pp.118-124
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• 2009

Esterase EM2L8 gene isolated from deep sea sediment was expressed in Escherichia coli BL21 (DE3) and the esterase activity of the cell-free extract was assayed using p-nitrophenyl butyrate-spectrophotometric method. Its optimum temperature was $40-45^{\circ}C$ and 45% activity of the maximum activity was retained at $15^{\circ}C$. The activation energy at $15-45^{\circ}C$ was calculated to be 4.9 kcal/mol showing that esterase EM2L8 was a typical cold-adapted enzyme. Enzyme activity was maintained for 6 h and 4 weeks at $30^{\circ}C$ and $4^{\circ}C$, respectively. When each ethanol, methanol, and acetone was added to the reaction mixture to 15% concentration, enzyme activity was maintained. In the case of DMSO, enzyme activity was kept up to 40% concentration. (S)-4-Chloro-3-hydroxy butyric acid is a chiral intermediate for the synthesis of Atorvastatin, a hyperlipemia drug. When esterase EM2L8 (40 U) was added to buffer solution (1.2 mL, pH 9.0) containing ethyl-(R,S)-4-chloro-3-hydroxybutyrate (38 mM), it was hydrolyzed into 4-chloro-3-hydroxy butyric acid with a rate of $6.8\;{\mu}mole/h$. The enzyme hydrolyzed (S)-substrate more rapidly than (R)-substrate. When conversion yield was 80%, e.e.s value was 40%. When DMSO was added, hydrolysis rate increased to $10.4\;{\mu}mole/h$. The plots of conversion yield vs e.e.s in the presence or absence of DMSO were almost same, implying that the reaction enantioselectivity was not changed by the addition of DMSO. Taken together, esterase EM2L8 had high activity and stability at low temperatures as well as in various organic solvents/aqueous solutions. These properties suggested that it could be used as a biocatalyst in the synthesis of useful pharmaceuticals.

• Journal of Nutrition and Health
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• v.35 no.3
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• pp.303-313
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• 2002

The purpose of this study was to compare the anthropometry, blood pressure, blood lipid levels, and nutrient intakes in three groups: a group with an impaired fasting blood glucose (IFG) condition (62 males and 30 females); a group with normal blood glucose (73 males and 50 females); and a group with diabetes mellitus (DM) (79 males and 49 females). In male subjects, body mass index (BMI) and obesity index values were significantly higher in the IFG group than in normal and DM groups, but waist/hip ratio (WHR), systolic blood pressure, and diastolic blood pressure were not significantly different from those of the DM group. In female subjects, there was no difference in body weight, BMI, obesity index and WHR values between the IFG and the DM groups. The prevalence of obesity in the IFG group (males 43.6%, females 76.7%) was the highest among the three groups. The percentage of high SBP (40.0%) and high DBP (52.0%) in male subjects of the IFG group was significantly greater than in the DM group or the normal group. In the male subjects, the serum triglyceride concentration was significantly higher in the DM group than in the normal and IFG groups. There was no difference in various nutrient intakes(energy, carbohydrate, protein, fat, calcium, iron, vitamin A and cholesterol) among the three groups. In male subjects, the percentage of energy intake from alcohol was higher in the IFG group (7.0%) than that of the normal (4.5%) and the DM (5.6%) groups. The fasting blood glucose level had a positive correlation with WHR, TG, the athrogenic index and LDL-cholesterol/HDL-cholesterol. This study suggested that the IFG group had a higher obesity index, BMI, blood pressure and serum lipid levels (TG, cholesterol) than the normal or the DM group; furthermore, the IFG group had higher levels of alcohol intake and habits of taking unbalanced diets. Therefore, guidelines for IFG group should emphasize weight control, diet therapy, physical activities and regular balanced diets, in order to prevent diabetes in this group.

• Korean Journal of Optics and Photonics
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• v.13 no.4
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• pp.340-346
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• 2002

To understand the characteristics of the passively Q-switched Nd:YAG laser output energy with $Cr^{4+}$:YAG saturable absorbers, the transmissions of $Cr^{4+}$:YAG and the inversion population densities of Nd:YAG at the onset of Q-switch were experimentally analysed. The measured transmissions at the onset of Q-switch were 0.70$\pm$0.02 and 0.62$\pm$0.02 for the 0.48 and 0.38 of initial transmission, respectively. It means that the initial transmission loss of $Cr^{4+}$:YAG absorber is reduced in a low Q-state due to the initial absorbing effect of $Cr^{4+}$:YAG. In pumping stage, $Cr^{4+}$:YAG has absorbing processes due to the fluorescence and amplified spontaneous emissions of the Nd:YAG even if there is no laser oscillation. The minimum population inversion densities for Qswitch were approximately 3.7${\times}{10^{17}}$ and 4.0${\times}{10^{17}}$ $cm^{-3}$, respectively. At the beginning of Q-switch, the number density of $Cr^{4+}$ions in the ground state of $Cr^{4+}$:YAG was approximately 1.4${\times}{10^{17}}$ $cm^{-3}$ and the ratio of the ground to the excited state of absorbing $Cr^{4+}$ions was 0.44 both. The modified theoretical output energies with the initial absorbing effect were 18 and 18.5 mJ. The measured output energies were 17$\pm$1 and 18$\pm$1.5 mJ, respectively. The quantum extraction efficiencies of Q-switch were 0.32 both. The theoretical Q-switched output results with the initial absorbing effect of the saturable absorber are a good agreement with the experimental results.

• Journal of the Korean Vacuum Society
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• v.15 no.2
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• pp.201-208
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• 2006

Optical characteristics of InGaAs quantum dot (QD) laser structures with an Al native oxide (AlOx) layer as a current-blocking layer were studied by means of photoluminescence (PL), PL excitation, and spatially-resolved micro-PL techniques. The InGaAs QD samples were first grown by molecular-beam epitaxy (MBE), and then prepared by wet oxidation and thermal annealing techniques. For the InGaAs QD structures treated by the wet oxidation and thermal annealing processes, a broad PL emission due to the intermixing effect of the AlOx layer was observed at PL emission energy higher than that of the non-intermixed region. We observed a dominant InGaAs QD emission at about 1.1 eV in the non-oxide AlAs region, while InGaAs QD-related emissions at about 1.16 eV and $1.18{\sim}1.20eV$ were observed for the AlOx and the SiNx regions, respectively. We conclude that the intermixing effect of the InGaAs QD region under an AlOx layer is stronger than that of the InGaAs QD region under a non-oxided AlAs layer.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.5
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• pp.557-564
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• 2006

This research was planned and executed to evaluate how the composition of Yak-sun (oriental diet therapy) can effect health conditions of people who are suffering from diet-related diseases like obesity and hyper lipidemia by taking Yak-sun in a form of nutritional supplement with our daily meals. We produced Yak-sun tea with $Ky\hat{a}lmy\hat{a}ngja$, Kamguk, $K\hat{u}m\hat{u}nhwa$, Ch'onkung and observed nutritional composition and evaluated how this tea effects on serum lipids and homocystein concentration by clinical practices. With this observation, we found out that this tea has significant effect on increasing of HDL-cholesterol, decreasing of LDL-cholesterol and homocysteine concentration, and we think that scientific and objective evaluation was done on the components of Yak-sun tea prescription. We concluded that we could apply the components not only in a form of tea, but also in other forms of various food. The information we received from this conclusion will be a basic information on how we can apply oriental medicinal resources into other food and will also be a stepping stone for medicinal herbs to step foot in the field of functional food research, which already draws sizable attention world-wide.

• KDI Journal of Economic Policy
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• v.13 no.1
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• pp.135-149
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• 1991

The economic policy of decreasing the electricity price is widely understood to have the effect of stabilizing the general price level and improving the income distribution. However, the impact of electricity price decrease on the income distribution is not quite sure although the electricity price decrease would increase the disposable income of all households. The electricity price change would affect the income distribution through three channels. The first impact on the income distribution is made through the electricity price sructure; Korean electricity price structure is designed to subsidized the industrial sector at the cost of household consumption sector in the sense that the price per unit electricity for industrial sector is much lower than that for household consumption sector. The second impact on the income distribution is created through the disposable household income effect of the price decrease; Relative disposable income effect among households appeared higher to lower income household group and this relative disposable income effect seem to improve the income distribution although the net effect is very small. The third impact on the income distribution is formulated through the net profit effect of entreprise sector; This unearned net profit increase to the already rich industrial entrepreneurs group could create a negative income distribution effect. A simulation of 10% electricity price decrease with all the price structure given was attempted to calculate the net effect of income distribution and it was found the net income distribution effect of flat electricity price decrease to be negative contrary to the general understanding. The income distribution effect would only be one criterion among many other criteria considered in the electricity price making process. The electricity price decrease would be helpful to the price stabilization and price competitiveness of industrial sector. However, it does not improve the general income distribution status by the electricity price decrease with the price structure given.

• The korean journal of orthodontics
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• v.29 no.6 s.77
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• pp.673-688
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• 1999

This study was conducted in order to analyze the mechanical characteristics of multiloop edgewise archwire (MEAW). The purposes were 1) to compare load deflection rate (LDR) of MEAW with that of various other arch wires in the individual interbracket span, 2) to compare the wire stiffness in the interbracket span with that in the multi-L-loop region (the span from distal border of the bracket of the lateral incisor to the mesial border of the buccal tube of the second molar), and 3) to verify the experimental results with theoretically derived formula. The single L-loops of five different horizontal lengths and multi-L-loops for the upper and lower arches were made out of .$016\times.022$ permachrome stainless steel wire. Straight segment of plain stainless steel, TMA and NiTi wire of the same dimension were prepared. The LDR was measured using Instron model 4466 with the load cell of 50N capacity at cross head speed of 1.0mm/min, and maximum deflection of 1.0mm. Five specimens were tested under each experimental condition. The wire stiffness number for each interbracket region and multi-L-loop region was calculated from the LDR and the interbracket spans. By dividing the theoretical model of multi-L-loop into 35 linear segments, the energy stored in each segment was obtained. Then the LDR and wire stiffness of single L-loop and multi-L-loop were calculated and compared. The findings were as follows : 1) The average LDR of MEAW in the individual interbracket region was 1/1.53 of that of the NiTi,1/2.47 of TMA and 1/5.16 of the plain stainless steel wire. 2) The wire stiffness of MEAW in the multi-L-loop region was 1.53 times larger than that in the interbracket region, and the LDR was almost twice as large as that of NiTi in that region. 3) According to the theoretically derived equation, the wire stiffness of the single L-loop was lower than that of multi-L-loop. The results of this study suggest that MEAW has the unique mechanical Property which could allow individual tooth movement and transmit elastic force effectively through the entire arch wire.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.2
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• pp.216-225
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• 2015

The purpose of this study was to evaluate night time eating habits, dietary habits, and nutrient intake in university students according to residence type. A survey was conducted by administering questionnaires to 664 students. Questionnaire interview and 24-h dietary recall were conducted. Subjects were divided into three groups according to residence type: dormitory boarding (DB group, N=313), self-boarding (SB group, N=246), and living with parents (LWP group, N=105). Average ages in the DB, SB, and LWP groups were 21.3, 22.2, and 22.1 years, respectively. There were no significant differences in body mass index between the three groups. In total, 77.3% of students regularly ate night time snacks. The proportion of students who reported night time eating was 84.0% in the DB group, 73.6% in the SB group, and 65.7% in the LWP group (P<0.001). In terms of food types consumed during night time eating, the DB group showed a significantly higher rate of consumption of fried chicken and flour-based foods than the SB and LWP groups, whereas the SB group showed a significantly higher rate of consumption of alcohol beverages than the DB and LWP groups. Energy, carbohydrates, protein, fat, vitamins, and mineral intakes were significantly higher in the DB group than in the SB and LWP groups. In addition, intake of cholesterol per 1,000 kcal was significantly higher in the DB group than in the SB and LWP groups. Thus, SB and DB students seemed to have more night time eating problems than LWP students. Accordingly, nutritional education is needed to support the development of healthier eating habits, in particular, night time eating habits, among students living in dormitories and in self-boarding situations.