• Korean Journal of Remote Sensing
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• v.37 no.2
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• pp.321-335
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• 2021

Particulate matter (PM10 and PM2.5 with a diameter less than 10 and 2.5 ㎛, respectively) can be absorbed by the human body and adversely affect human health. Although most of the PM monitoring are based on ground-based observations, they are limited to point-based measurement sites, which leads to uncertainty in PM estimation for regions without observation sites. It is possible to overcome their spatial limitation by using satellite data. In this study, we developed machine learning-based retrieval algorithm for ground-level PM10 and PM2.5 concentrations using aerosol parameters from Geostationary Ocean Color Imager (GOCI) satellite and various meteorological parameters from a numerical weather prediction model during January to December of 2019. Gradient Boosted Regression Trees (GBRT) and Light Gradient Boosting Machine (LightGBM) were used to estimate PM concentrations. The model performances were examined for two types of feature sets-all input parameters (Feature set 1) and a subset of input parameters without meteorological and land-cover parameters (Feature set 2). Both models showed higher accuracy (about 10 % higher in R2) by using the Feature set 1 than the Feature set 2. The GBRT model using Feature set 1 was chosen as the final model for further analysis(PM10: R2 = 0.82, nRMSE = 34.9 %, PM2.5: R2 = 0.75, nRMSE = 35.6 %). The spatial distribution of the seasonal and annual-averaged PM concentrations was similar with in-situ observations, except for the northeastern part of China with bright surface reflectance. Their spatial distribution and seasonal changes were well matched with in-situ measurements.

• Korean Journal of Remote Sensing
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• v.36 no.6_3
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• pp.1721-1732
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• 2020

Elementary school students spend a lot of time in a school and are more exposed to indoor air pollution. Also the students are physically growing and have a relatively high respiratory rate per unit weight compared to adults, so it is known that there is a high sensitivity to indoor air pollution. Therefore, indoor air quality in a school is becoming an important factor for the student's health. In this study, a correlation analysis using levels of indoor and outdoor Particulate Matter (PM) measured from five elementary schools in Seoul was performed to evaluate the effect of outdoor PM on indoor PM. PM ratio and indoor/outdoor (I/O) ratio were also analyzed to investigate the actual condition of indoor air quality and effect of outdoor PM on indoor PM. As a result, the correlation between indoor and outdoor PM in elementary school was more significant in PM2.5 and PM1 than PM10. In the case of I/O ratio, the I/O ratio of PM10 was higher than that of 1 in four elementary schools except SD (BB:2.21, NS: 1.67, IS: 1.73, SI: 1.17). This indicates that the activity of students has a great effect on the concentration of indoor PM10.

• Journal of Embryo Transfer
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• v.25 no.1
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• pp.15-20
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• 2010

This study was performed to identify the optimal timing for oocyte donor replacement during OPU procedure. OPU was carried out to collect oocytes from every donor at an interval of $3{\sim}4$ days (2 times a week). The collected oocytes were matured in vitro in TCM-199 supplemented with 10% FBS, 10 mg/ml of FSH and 1 mg/ml of estradiol for 24 h. After 24 h of exposure to sperm, the presumptive zygotes were cultured in CR1aa medium supplemented with 4 mg/ml of BSA for 3 days before being changed to CR1aa medium with 10% of FBS for another $3{\sim}4$ days. The mean numbers of retrieved oocytes were remained constantly up to 3 months ($6.0{\pm}0.5$, $6.2{\pm}0.7$, $5.2{\pm}0.6$), but significantly decreased at over 4 to 6 months ($3.7{\pm}0.5$, $2.8{\pm}0.4$, $1.2{\pm}0.2$) (p<0.05). The blastocyst development potential was also very similar rate from 1 to 3 months (37.2%, 40.4% and 44.6%), but significantly decreased from 4 to 6 months (24.8%, 29.3% and 28.6%, respectively) (p<0.05). The production of OPU derived embryos in periods of 1 to 3 months ($2.2{\pm}0.3$, $2.5{\pm}0.3$ and $2.3{\pm}0.4$) were significantly higher than those in 4 to 6 months ($0.9{\pm}0.2$, $0.8{\pm}0.2$ and $0.3{\pm}0.2$, respectively) (p<0.05). In conclusion, the efficient periods for the production of OPU derived embryos was until 4 months, twice per week to produce over 64 transferable embryos and then replace new donor after 3 months use. The best replacement time is 3 months and could be maximized production of OPU derived embryos.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.4
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• pp.534-541
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• 2018

Concentrations of total particulate matter (TPM), $PM_{10}$ and $PM_{2.5}$ were measured at three different sites based on each different fuel type (solid, liquid and gas) used in thermal power plants operating in Yeosu and Gwangyang National Industrial Complexes during 2017. The highest concentrations of TPM, $PM_{10}$, and $PM_{2.5}$ were observed at the solid fuel facility, and these values were $3.356mg/Sm^3$, $2.342mg/Sm^3$ and $1.834mg/Sm^3$, respectively. The ratio of $PM_{2.5}$ to TPM was the highest value of 54.6% in solid fuel case, and the lowest was 35.7% found in liquid fuel case. As a result of analyzing 9 kinds of metal compound with respect to each particle size, the metal concentration of TPM is higher than those of $PM_{10}$ and $PM_{2.5}$ in all fuel types. Total concentrations of metal elements in TPM by fuel difference are $1.2702mg/Sm^3$ in solid fuel, 0.0603 mg/Sm3 in liquid fuel, and $0.0733mg/Sm^3$ in gas fuel, respectively. Relatively higher total metal concentration in gas fuel than in liquid fuel was found; and this could be higher Cr and Al concentrations in use of gas fuel. As a result of estimating the emission factors of each facility, in case of solid fuel, TPM emissions per electricity production were found to be 0.7080 kt/PJ, followed by liquid fuel and gas fuel. $PM_{10}$ and $PM_{2.5}$ emissions per hour of electricity production were similar to those of TPM.

• Natural Product Sciences
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• v.14 no.1
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• pp.1-11
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• 2008

Peroxynitrite ($(ONOO^-)$ is a cytotoxic species formed from nitric oxide and superoxide anion, which are highly implicated in the pathogenesis of oxidative stress-mediated diseases. The aim of this study was to investigate the scavenging effects of Phellinus linteus on authentic $ONOO^-$, and further phytochemical studies are planned that will attempt to identify the active principles. From the active EtOAc fraction, a mixture of fungisterol and 5-dihydroergosterol (1), a mixture of betulin and 1,2-benzenedicarboxylic acid bis (2-methyl heptyl) ester (2), protocatechualdehyde (3), protocatechuic acid (4), cirsiumaldehyde (5), hispidin (6), caffeic acid (7), phelligridin D (8), uracil (9), gallic acid (10), 2,5-dihydroxybenzoic acid (11), ferulic acid (12), 2,3-dihydroxybenzaldehyde (13), arbutin (14), isoferulic acid (15), guanosine (16), and ellagic acid (17) were isolated, and their structures were characterized based on spectroscopic data. All compounds except 3, 6, 7 and 16 were isolated for the first time from P. linteus. Compounds 3, 4, 6-8, 10-15, and 17 showed potent scavenging activity on $ONOO^-$, with $IC_{50}$ values of $2.06\;{\pm}\;0.10$, $3.45\;{\pm}\;0.57$, $0.71\;{\pm}\;0.05$, $2.78\;{\pm}\;0.36$, $5.42\;{\pm}\;0.26$, $1.13\;{\pm}\;0.02$, $1.82\;{\pm}\;0.17$, $0.91\;{\pm}\;0.19$, $1.59\;{\pm}\;0.09$, $1.88\;{\pm}\;0.07$, $1.22\;{\pm}\;0.37$, and $2.01\;{\pm}\;0.02\;{\mu}M$, respectively, as compared to the positive control, DL-penicillamine, with an $IC_{50}$ value of $5.04\;{\pm}\;0.06\;{\mu}M$.

• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.2
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• pp.1-17
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• 2022

This study analyzed the PM_2.5 pattern by using data measured for one year from June 2020 to May 2021 by 21 low-cost sensors installed near the Changwon National Industrial Complex in Changwon, Gyeongsangnam-do. For the PM_2.5 pattern, the land use types around the measuring points and meteorological factors such as air temperature and wind speed were considered. The PM_2.5 concentration was high from November to March in winter, and from 1 to 9 in the morning and early in the morning by time zone. The concentration of PM_2.5 was higher as it got closer to the industrial area, but the concentration was lower in the residential area and public facility area. In terms of meteorological factors, the higher the air temperature and wind speed, the lower the concentration of PM_2.5. As a result of this study, it was possible to identify the PM_2.5 patter near Changwon National Industrial Complex. This result will be useful data that can be used in urban and environmental planning to improve air quality including PM_2.5 in urban area in the future.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.43 no.4
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• pp.221-228
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• 2017

Objectives: The purpose of this study was to establish normative data for healthy Korean adults by measuring the maximal strength and endurance scores of the tongue, lip, and cheek, and to examine correlations between these measurements. Materials and Methods: This study included 120 subjects that were divided into three groups according to age: young (20-39 years), middle-aged (40-59 years), and older (over 60 years); and by gender. Measurements were taken using the Iowa Oral Performance Instrument (IOPI). Results: The mean maximal tongue strengths were as follows: young men ($46.7{\pm}10.2kPa$) and women ($32.1{\pm}7.9kPa$), middle-aged men ($40.9{\pm}9.3kPa$) and women ($36.9{\pm}8.6kPa$), and older men ($35.2{\pm}9.0kPa$) and women ($34.5{\pm}6.9kPa$). The mean tongue endurance scores were: young men ($28.8{\pm}12.6$ seconds) and women ($20.8{\pm}13.5$ seconds), middle-aged men ($17.0{\pm}8.5$ seconds) and women ($15.3{\pm}5.2$ seconds), and older men ($15.8{\pm}6.7$ seconds) and women ($17.9{\pm}8.1$ seconds). The mean maximal lip strengths were: young men ($11.6{\pm}3.0kPa$) and women ($11.4{\pm}3.8kPa$), middle-aged men ($11.4{\pm}4.2kPa$) and women ($11.1{\pm}5.1kPa$), and older men ($14.5{\pm}3.9kPa$) and women ($11.7{\pm}2.6kPa$). The mean lip endurance scores were: young men ($41.1{\pm}23.9$ seconds) and women ($22.4{\pm}21.7$ seconds), middle-aged men ($24.3{\pm}10.3$ seconds) and women ($30.5{\pm}13.4$ seconds), and older men ($24.9{\pm}11.0$ seconds) and women ($12.8{\pm}7.6$ seconds). The mean maximal cheek strengths were: young men ($24.5{\pm}4.6kPa$) and women ($20.5{\pm}4.3kPa$), middle-aged men ($25.2{\pm}6.4kPa$) and women ($21.2{\pm}5.5kPa$), and older men ($22.4{\pm}5.3kPa$) and women ($18.0{\pm}4.8kPa$). The mean cheek endurance scores were: young men ($47.8{\pm}24.4$ seconds) and women ($43.9{\pm}25.0$ seconds), middle-aged men ($27.3{\pm}11.3$ seconds) and women ($20.0{\pm}14.6$ seconds), and older men ($21.7{\pm}14.5$ seconds) and women ($17.2{\pm}11.4$ seconds). Conclusion: The data collected in this study will provide an important database of standardized measurements for maximal strength and endurance scores of the tongue, lip and cheek in healthy, normal Koreans.

• Journal of Chest Surgery
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• v.25 no.2
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• pp.125-130
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• 1992

To evaluate the effect of oxygenation[95% O2+5% CO2] of St. Thomas Hospital No.2 cardioplegic solution[Plegisol], 20 isolated perfused rat hearts were studied under hyp-othermic[20oC] ischemic arrest for 2 hours with infusion of cardioplegic solution every 30 minutes throughout the ischemic period. Ten isolated hearts were studied with the oxygenated cardioplegic solution and 10 another isolated hearts with the nonoxygenated one. Mean oxygen tensions of the nonoxygenated and oxygenated cardioplegic solutions were 150mmHg and 470mmHg, respectively. Two in 10 hearts infused with the nonaxygenated cardioplegic solution were not recovered from nonworking heart due to persistent ventricular fibrillation. In comparing hem-odynamic parameters between both groups, the mean postischemic recovery[expressed as a percentage of its preischemic control value] was significantly greater with the oxygenated solution[in 10 recovered hearts] than the nonoxygenated solution[in 8 recovered hearts] [95.9$\pm$1.8% compared with 88.5$\pm$2.9% in peak aortic pressure, p<0.05, 75.7$\pm$5.2% compared with 43.5$\pm$6.5% in aortic flow, p<0.01, 75.5$\pm$4.6% compared with 54.1$\pm$5.6% in cardiac output, p<0.01, 78.3$\pm$4.6% compared with 60.3$\pm$4.6% compared with 60.3$\pm$6.2% in stroke volume, p<0.05, and 80.4$\pm$5.3% compared with 58.6$\pm$7.0% in dP/dT, p<0.05]. It is concluded that oxygenation of St. Thomas Hospital No.2 cardioplegic solution improves cardiac electrical stability and postischemic hemodynamic recovery after ischemic arrest in the isolated perfused rat heart.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.3
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• pp.406-417
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• 2018

In this study, $PM_{2.5}$ samples were collected during approximately 3 years in Chuncheon, a small residential and tourist city, in Korea. The average $PM_{2.5}$ concentration was $26.9{\mu}g/m^3$, exceeding the annual national air quality standard. $PM_{2.5}$ showed typical seasonal variation, having higher concentration in winter and lower concentration in summer. Sixteen metallic elements in $PM_{2.5}$ were also analyzed, and K was the highest contributor especially in late fall and winter. In addition, K considerably increased for the top 10% of $PM_{2.5}$ samples and showed the highest correlation coefficient with $PM_{2.5}$ among all other metallic elements. These results suggest that the combustion of agricultural residue and other biomass, the major source of K was likely to be important to high $PM_{2.5}$ concentration events in this city. Crustal elements including Al, Fe, Si, Ti, Mg showed high concentration in spring while Cr, Cu and Ni were relatively consistent throughout a year. Principal component analysis was used to trace the sources, and soil re-suspension, combustion of biomass and fossil fuels, and asphalt concrete production were identified as the main sources of $PM_{2.5}$.

• Journal of Preventive Medicine and Public Health
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• v.20 no.1 s.21
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• pp.97-113
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• 1987

This study was carried out to know physical growth and development, physical and nutritional indices and body fat weight and so forth by semi-longitudinal research method to measure body height, body weight, chest girth and sitting height of 260 of general high school and 306 of vocational high school 3rd grade students who are living in Seoul and born from 1966 March 1st to 1967 Feb.28th. The results are as follows: 1) Physical growth and development Growth in terms of body height showed one step straight linear development, andthat of body weight showed two step straight linear development in each section in high school. The age of cross over between two sexes of general high school students was between 10.6 to 12. 3 years in body height, between 10.8 to 13 years in body weight, between 11.2 to 14.6 years in chest girth and between 10 to 13 years in sitting height. The age of cross over between two sexes of vocational high school students was between 10.5 to 12.5 years in body height, between 10.5 to 12.5 years in body weight, between 10.5 to 12.5 years in chest girth and between 10.5 to 12.5 years in sitting height. In this periods, female group was superior to male group and after that male group was superior to female group again. The growth of vocational school students was superior to that of general school students in both sexes in terms of body height and body weight significantly. 2) Physical growth and nutritional indices In all cases of relative body weight, relative chest girth and relative sitting height, it was found to be increasing thereafter with advancing ages. In cases of $R{\"{o}}hrer$ index and Kaup index, it was found to be reaching to normal state thereafter with advancing ages. In each case of Vervaeck and Pelidisi index, it was found to be increasing and reaching to normal state thereafter with advancing ages. 3) Total body fat by vital measuring method Average values of body surface area, body volume and body density are measured indirectly by using the body height and body weight as Table 12, 13 and 14. The rate of body fat weight of general high school students was from minimum $11.96{\pm}3.53%(3.33{\pm}1.10kg$) to maximum $18.25{\pm}6.46%(9.08{\pm}2.01kg$) in male and from $25.88{\pm}3.62%(7.96{\pm}0.78kg$) to $43.00{\pm}7.22%(12.91{\pm}1.21kg$) in female. The rate of body fat weight of vocational high school students was from minimum $11.20{\pm}2.88%(3.32{\pm}1.13kg$) to maximum $17.16{\pm}5.88(10.83{\pm}3.16kg$) in male and from minimum $25.11{\pm}2.26%(7.91{\pm}0.89kg$) to maximum $42.16{\pm}7.96%(13.22{\pm}1.75kg$) in female.