• Journal of Environmental Impact Assessment
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• v.27 no.5
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• pp.431-446
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• 2018

In this study, chemical characteristics of $PM_{2.5}$ samples collected in an agricultural area in Nonsan of Korea were investigated focusing on of black carbon, 3 inorganic ions and 22 trace elements. It was found that the relative error and relative standard deviation of many trace elements fell below 10%, which indicates good analytical accuracy and precision. The mean values of $PM_{2.5}$ in an agricultural area were exceeded by new Korean air quality standard of March 2018. The concentration of $PM_{2.5}$ was well correlated with those of black carbon and ions. The concentrations of trace elements were in a wide range of seven orders of a magnitude. Based on these $PM_{2.5}$ data sets, a total of 6 sources were identified using PMF (Positive Matrix Factorization; secondary aerosol (34.4%), soil/road dust (20.1%), biomass burning (16.9%), incineration/fuel combustion (13.2%), vehicle exhaust(12.2%), sea-salt (3.17%). Results of our study indicate that it is very important to control illegal burning activities in agricultural area.

• Preventive Nutrition and Food Science
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• v.4 no.1
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• pp.62-69
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• 1999

The present study was aimed at investigating whether there are sex-related differences in serum levels of lipids, retinol , $\alpha$-tocopherol and ascorbic acid in Korean adults. Serum levels of antioxidant vitamins and lipids were determined algon with anthropometric measurements in 53 healthy male subjects with mean age 42.7$\pm$12.2 years and 44 female subjects with mean age 46.7$\pm$10.3 years. from Taegu in Korea. BMI and W/H ration of the men were 22.66$\pm$2.47, 0.88$\pm$0.04 and those fo thewomen were 23.36$\pm$3.44, 0.84$\pm$0.05 respectively. Systolic and diastolic blood pressures were 121.67$\pm$14.8, 79.3$\pm$12.4 in the men and 123.1 $\pm$17.5 , 78.8$\pm$10.9 in the women respectively. Average serum levels of total cholesterol, LDL-and HDL-cholesterol and triglyceride were 165.8$\pm$36.4, 102.6$\pm$31.2, 41.1$\pm$10.5 and 110.2$\pm$57.8mg/dl in the and 169.1$\pm$39.1, 113.7$\pm$36.2, 38.1 $\pm$8.6, and 85.2$\pm$37.7mg/dl in the women respectively. Thirteen percent of menans thirtyeight percent of women had LDL-cholesterol over 130mg/dl. Serum levels of retinol, $\alpha$tocopherol, ad ascorbic acid were 43.25 $\pm$15.51, 17.93$\pm$7.07, 115.24$\pm$63.25ug/dl in the men and 31.80$\pm$15.39, 17.41$\pm$6.12, an d144.99$\pm$89.87ug/dl in the women respectively. Serum vitamin E showed positive correlations with total cholesterol and LDL-cholesterol and triglyceride.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.4
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• pp.1483-1491
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• 2010

The purpose of this study was to examine current status of the types of dental filling materials and preventive materials among Korean children in mixed dentition. Seven elementary schools were randomly selected from four metropolitan regions in South Korea. The total of 711 children aged 9-10 years old were examined with their parents’ informed consents. Oral examination was conducted by one trained dentist. The mean number of dfs was $7.9{\pm}8.0$ ($ds=1.3{\pm}2.5,\;fs=6.6{\pm}7.6$) and DMFS was $1.4{\pm}2.2$ ($DS=0.2{\pm}0.8,\;FS=1.1{\pm}2.1$). The average of filled surfaces using amalgam, composites, sealants, and others were $2.8{\pm}3.9,\;1.6{\pm}2.8,\;2.9{\pm}3.2$, and $4.5{\pm}7.0$, respectively. The use of dental filling material according to region, the amalgam was the highest in Daegu and the resin was the highest in Pusan. In permanent teeth, about 70% of total filling surfaces had sealant and about 20% was resin fillings, and the proportion of amalgam filling surfaces was less than 10%.

• Atmosphere
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• v.20 no.3
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• pp.221-228
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• 2010

Aerosol particles with different size-cuts ($PM_{10}$, $PM_{2.5}$, and $PM_{1.0}$) were collected at Gosan Superstation on Jeju Island from August 2007 to June 2008. Mean concentrations of $PM_{10}$, $PM_{2.5}$ and $PM_{1.0}$ were $29.28{\mu}gm^{-3}$, $17.83{\mu}gm^{-3}$, and $14.30{\mu}gm^{-3}$, respectively. Soluble ions comprised 45.7%, 53.9%, and 60.3% of the total mass of $PM_{10}$, $PM_{2.5}$, and $PM_{1.0}$, respectively. While sulfate was the most dominant species of fine mode ($PM_{1.0}$), nitrate was enriched in coarse mode ($PM_{1.0-10}$). When the concentrations of coarse mode particles were greatly increased, nitrate tended to be enhanced in coarse mode with high calcium but low sulfate concentrations. During the high $PM_{1.0}$ events, however, nitrate was increased with sulfate at fine mode. Particularly, nitrate concentrations were substantially enhanced during high particle episodes, leading high ratios of nitrate to sulfate in air under northwest wind during wintertime. On the other hand, the levels of nitrate were lower than those of sulfate at average particle concentrations. The backward air mass trajectories indicated that nitrate concentrations were elevated in air arriving Gosan passing through Santung peninsula or near South Korea.

• Korean Journal of Food Science and Technology
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• v.43 no.2
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• pp.230-234
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• 2011

According to the Codex committee, the maximum allowable level for lead in fruits is 0.1 mg/kg. This survey was conducted as a surveillance program following the establishment of safety guideline for fruits in Korea. Concentrations of lead (Pb), cadmium (Cd), arsenic (As) and mercury (Hg) were measured in 927 samples using a ICP-MS and a mercury analyzer. The recoveries of microwave digestion method were 86.0-110.4% for Pb, 81.0-104.0% for Cd and 82.0-104.7% for As by standard addition method. The recovery of direct mercury analyzer was 106.5% for Hg. The average levels of Pb in ${\mu}g/kg$ were $10.0{\pm}12.8$ for apple, $8.8{\pm}10.9$ for pear, $4.1{\pm}4.4$ for persimmons, $14.9{\pm}12.3$ for mandarin, $7.1{\pm}6.5$ for orange, $3.1{\pm}3.3$ for banana, $8.8{\pm}8.9$ for kiwi, and $9.3{\pm}9.7$ for mango. The average levels of Cd in ${\mu}g/kg$ were $0.4{\pm}0.3$ for apple, $2.0{\pm}1.6$ for pear, $0.3{\pm}0.3$ for persimmon, $0.1{\pm}0.1$ for mandarin, $0.1{\pm}0.1$ for orange, $1.3{\pm}1.8$ for banana, $0.5{\pm}0.5$ for kiwi, and $0.7{\pm}0.6$ for mango. The average levels of As in ${\mu}g/kg$ were $2.0{\pm}2.1$ for apple, $1.2{\pm}1.3$ for pear, $1.5{\pm}1.2$ for persimmon, $0.8{\pm}0.3$ for mandarin, $1.5{\pm}0.5$ for orange, $1.8{\pm}1.2$ for banana, $1.6{\pm}1.5$ for kiwi, and $1.2{\pm}1.5$ for mango. The average levels of Hg in ${\mu}g/kg$ were $0.5{\pm}0.4$ for apple, $0.3{\pm}0.2$ for pear, $0.2{\pm}0.1$ for persimmon, $0.2{\pm}0.1$ for mandarin, $0.2{\pm}0.1$ for orange, $0.2{\pm}0.0$ for banana, $0.2{\pm}0.2$ for kiwi, and $0.6{\pm}0.2$ for mango. Based on the Korean public nutrition report 2005, these levels (or amounts) are calculated only at 0.17% for Pb, 0.013% for Cd and 0.006% for Hg of those presented in provisional tolerable weekly Intake (PTWI) which has been established by FAO/WHO. Therefore, the levels presented here are presumed to be adequately safe.

• Korean Journal of Environment and Ecology
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• v.25 no.4
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• pp.573-580
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• 2011

Litter production, nutrient concentration of each component of litterfall and amount of nutrients input to forest floor via litterfall were investigated for four years from May 2005 through April 2009 in Quercus variabilis forest at Mt. Worak National Park. Amount of litterfall in 2005, 2006, 2007, 2008 were 5.181, 5.372, 5.314, 5.361 ton $ha^{-1}yr^{-1}$, respectively. Average amount of litterfall for four years was 5.307${\pm}$0.09 ton $ha^{-1}yr^{-1}$. Average percentage of leaf litter, branch and bark, reproductive organ and the miscellaneous for four years were 67.5${\pm}$1.9, 13.3${\pm}$0.8, 10.1${\pm}$0.5 and 9.1${\pm}$1.2%, respectively. Average amount of N, P, K, Ca and Mg returned to forest floor via litterfall for four years in this Q. variabilis forest were 44.47${\pm}$6.70, 2.50${\pm}$0.25, 12.26${\pm}$0.30, 17.23${\pm}$2.32 and 9.56${\pm}$0.54 kg $ha^{-1}yr^{-1}$, respectively.

• Tuberculosis and Respiratory Diseases
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• v.48 no.5
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• pp.766-772
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• 2000

Background : Pressure rise time (PRT) is the time in which the ventilator aclieves the set airway pressure in pressure-targeted modes, such as pressure control ventilation (PCV). With varying PRT, in principle, the peak inspiratory flow rate of the ventilator also varies. And if PRT is set to a shorter duration, the effective duration of target pressure level would be prolonged, which in turn would increase inspiratory tidal volume(Vti) and mean airway pressure (Pmean). We also postulated that the increase in Vti with shortening of PRT may relate inversely to the patients' basal airway resistance. Methods : In 13 paralyzed patients on PCV (pressure control 18$\pm$9.5 cm $H_2O$ $FIO_2\;0.6\pm0.3$, PEEP 5$\pm$3 cm $H_2O$, f 20/min, I : E1 : 2) with Servo 300 (Siemens-Elema, Solna, Sweden) from various causes of respiratory failure, PRT of 10 %, 5 % and 0 % were randomly applied. At 30 min of each PRT trial, peak inspiratory flow (PIF, L/sec), Vti (ml), Pmean (cm $H_2O$) and ABGA were determined. Results : At PRT 10%, 5%, and 0%, PIF were 0.69$\pm$0.13, 0.77$\pm$0.19, 0.83$\pm$0.22, respectively (p<0.001). Vti were 425$\pm$94, 439$\pm$101, 456$\pm$106, respectively (p<0.001), and Pmean were 11.2$\pm$3.7, 12.0$\pm$3.7, 12.5$\pm$3.8, respectively (p<0.001). pH were 7.40$\pm$0.08, 7.40$\pm$0.92, 7.41$\pm$0.96, respectively (p=0.00) ; $PaCO_2$ (mm Hg) were 47.4$\pm$15.8, 47.2 $\pm$15.7, 44.6$\pm$16.2, respectively (p=0.004) ; $PAO_2-PaO_2$ (mm Hg) were 220$\pm$98, 224$\pm$95, 227$\pm$94, respectively (p=0.004) ; and $V_n/V_T$ as determined by ($PaCO_2-P_E-CO_2$)/$PaCO_2$ were 0.67$\pm$0.07, 0.67$\pm$0.08, 0.66$\pm$0.08, respectively (p=0.007). The correlation between airway resistance and change of Vti from PRT 10% to 0% were r= -0.243 (p=0.498). Conclusion : Shortening of pressure rise timee during PCV was associated with increased tidal volume, increased mean airway pressure and lower $PaCO_2$.

• 산업보건소식
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• no.48
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• pp.9-18
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• 1987

The results of this study which had been investigated to analyse heavy metal levels and to compare lead, cadmium, copper and zinc concentration in urine of children who lived around the industrial area and the agricultural area. Samples were collected and analyzed from September to December 1986 from 7-9 years old children living in Seoul (4 7 cases), lri ( 64 cases) industrial area and Chinan (56 cases) agricultural area. The summarized results were as follows: 1) The concentrations of lead were Seoul 28.7 $\pm$17.7 ug/l, lri 25.3 $\pm$7.5 ug/l and Chinan 19.3 $\pm$5.2 ug/l 2) The concentrations of cadmium were Seoul 1.5 $\pm$0.8 ug/l, Iri 1.4 $\pm$0.5 ug/l and chinan 0.9 $\pm$0.3 ug/l 3) The concentrations of copper were Seoul 12.8 $\pm$7.0 ug/l, Iri 10.5 $\pm$8.4 ug/l and Chinan 10.0 $\pm$4.5 ug/l 4) The concentrations of zinc were Seoul 383 $\pm$279 ug/l, Iri 329 $\pm$133 ug/l and Chinan 267 $\pm$181 ug/l 5) In lead, cadmium and zinc concentration of children, there were statistical difference between the industrial area and the agricultural area 6) There were no indicated significantly levels by the Sex

• Korean Journal of Remote Sensing
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• v.37 no.6_2
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• pp.1881-1890
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• 2021

Particulate matter (PM) affects the human, ecosystems, and weather. Motorized vehicles and combustion generate fine particulate matter (PM_2.5), which can contain toxic substances and, therefore, requires systematic management. Consequently, it is important to monitor and predict PM_2.5 concentrations, especially in large cities with dense populations and infrastructures. This study aimed to predict PM_2.5 concentrations in large cities using meteorological and chemical variables as well as satellite-based aerosol optical depth. For PM_2.5 concentrations prediction, a random forest (RF) model showing excellent performance in PM concentrations prediction among machine learning models was selected. Based on the performance indicators R², RMSE, MAE, and MAPE with training accuracies of 0.97, 3.09, 2.18, and 13.31 and testing accuracies of 0.82, 6.03, 4.36, and 25.79 for R², RMSE, MAE, and MAPE, respectively. The variables used in this study showed high correlation to PM_2.5 concentrations. Therefore, we conclude that these variables can be used in a random forest model to generate reliable PM_2.5 concentrations predictions, which can then be used to assess the vulnerability of schools to PM_2.5.

• Journal of Life Science
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• v.16 no.1
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• pp.22-29
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• 2006

Effect of microbial products made of Bacillus stearothermophilus DL-3 on growth of chickens and pigs was investigated. Two types of microbial product were made in this study. One is the microbial product made of culture broth of B. stearothemophilus DL-3 and rice bran which named as the microbial product A. The other is the microbial product made of culture broth of B. stearothermophilus DL-3, apple pomace, soybean pomace and rice bran which named as the microbial product B. Chickens were divided into three groups and each group was fed with $100\%$ general feed, $90\%$ general feed supplemented with $10\%$ microbial product A or $90\%$ general feed supplemented with $10\%$ microbial product B. The average chicken weight of each group was $41.1{\pm}2.5g,\;41.6{\pm}3.2g\;and\;42.3{\pm}2.9g$ and those after 28 days was $547.7{\pm}91.7g,\;560.1{\pm}17.2g\;and\;562.2{\pm}32.5g$, respectively. The average weight gain for each group was 506.6 g, 518.6 g and 519.9 g, respectively, and weight increases of groups fed with $90\%$ general feeder and $10\%$ microbial product A and B were $2.4\%\;and\;2.6\%$ higher than the group fed with $100\%$ general feed. Pigs were also divided into three groups and each group was fed like chickens. The average weight of each group was $9.3{\pm}1.0kg,\;9.4{\pm}1.1kg\;and\;9.6{\pm}1.0kg$ and those after 37 days was $19.3{\pm}4.1kg,\;20.2{\pm}3.9kg\;and\;20.8{\pm}4.2kg$, respectively. The average Weight gain for each group was 10.65 kg, 10.82 kg and 11.20 kg, respectively, and weight increases of groups fed with $90\%$ general feeder and $10\%$ microbial product A and B were $1.6\%$ and $5.2\%$ higher than the group fed with $100\%$ general feed.