• Clinical and Experimental Pediatrics
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• v.51 no.12
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• pp.1310-1314
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• 2008

Purpose : This study aimed to assess the prevalence of obesity, hypertension, and hyperlipidemia in children from low-income families in Gunpo and to evaluate whether economic status affects the prevalence of obesity. Methods : Between October 2007 and March 2008, 341 children (167 girls and 174 boys; age, 6 to 13 years) were enrolled in this study. All these children came from families who earned minimum wages and who were supported by government. We measured height, weight, and blood pressure and performed laboratory examinations, including total cholesterol, high-density lipoprotein cholesterol, and triglycerides. Body mass index (BMI) was calculated using weight and height. We compared the prevalence of obesity, hypertension, and hyperlipidemia in children from low-income families with the prevalence of these maladies found in other studies. Results : Prevalence of obesity ($BMI{\geq}95^{th}$) was 7.1%. Prevalence of hypertension and hyperlipidemia was 8.2% and 16.7%, respectively. In the obese group, prevalence of hypertension and hyperlipidemia was 25.0% and 45.8%, respectively. Obesity and hyperlipidemia were slightly more frequent in our study than those found in other reports, and the prevalence of hypertension in the obese group was very high compared with statistics from the Korean National Health and Nutrition Examination Survey (25% vs. 19.5%) and those from other reports. Conclusion : Low-income status was associated with an increased incidence of obesity, hyperlipidemia, and hypertension. Hypertension showed an especially strong association with economic status, which seemed to correlate with genetic, environmental, and dietary effects.

• International Journal of Highway Engineering
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• v.3 no.2 s.8
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• pp.131-140
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• 2001

Concrete pavement of Jungbu Expressway composed of CRCP(Continuously Reinforced Concrete Pavement) and JCP(Jointed Concrete Pavement). The CRCP was firstly constructed and applied to new expressway in Korea. It is a good source of the study to analyze the performance of CRCP and JCP because it experiences same amount of traffic and environmental loading. Up to the present, condition survey has conducted several times during 13 years but roughness measurement has not been carefully conducted. Through comparisons among several types of pavement(CRCP, JCP, Asphalt) by roughness, CRCP is superior to JCP. In addition, connected sections in the highway such as bridges and tunnels that have higher IRI values, about 5mm/m, than normal sections should be considered appropriated maintenance such as diamond grinding. The relationship between IRI and distresses carried out by Korea Highway Cooperation in 1999 skewed that the number of crack is related to IRI value in JCP, while other distresses of JCP and CRCP are not shown clearly. The comparison study with IRI values between Jungbu Expressway and GPS-3(JCP) and GPS-5(CRCP) of LTPP data also showed that roughness of Jungbu Expressway is not inferior to that of the state. Some of section showed larger values of IRI are linked with under-9round structures for passages and drainages. The overall performance considering only roughness, the CRCP is also superior to JCP in sections with under-ground tunnels.

• Applied Microscopy
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• v.27 no.2
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• pp.121-130
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• 1997

It has been demonstrated that majority of cells in the mammalian body such as myocytes and epithelial cells of skin and intestine respond to mechanical force or environmental factors and exhibit partial disruption of cell membrane, i. e., cell wounding, even in a physiological condition. Myocardial cells are rather apt to be wounded than other cells since they are definitely exposed to mechanical stress by contraction-relaxation and blood flow. However, the mechanism how myocardial cells protect themselves against cell wounding is not yet clarified. On this background, the present study was performed to elucidate whether albumin leakage is related to cell wounding and to assess whether diltiazem, a potent calcium channel blocker, is beneficial in isoproterenol-induced cell wounding in the heart. Hearts isolated from New Zealand White rabbits ($1.5\sim2.0kg$ body weight, n=20) were perfused with Tyrode solution by Langendorff technique. After stabilization of baseline hemodynamics, the hearts were subjected to bolus administration of isoproterenol and diltiazem as following order: $1.6{\mu}M$ isoproterenol at zero min (the beginning point): $16{\mu}M$ diltiazem at 20min; $1.6{\mu}M$ isoproterenol at 25min; $16{\mu}M$ isoproterenol at 45 min; $160{\mu}M$ diltiazem at 65 min; $16{\mu}M$ isoproterenol at 70 min. During all experiments, the left ventricular function was recorded, albumin leakage in the coronary effluents was analyzed by electrophoresis and Western blot, and myocardial cell membranes were examined by conventional transmission electron microscopy. Data were analyzed by t-test and linear regression test. Isoproterenol significantly increased the inotropic and chronotropic contractions, coronary flow, and frequency of arrhythmia, however, diltiazem did not influence on hemodynamics except decrease in the frequency of arrhythmia and a slight decrease in contractility. Isoproterenol also resulted partial disruption of myocardial cell membrane and inclose in albumin leakage, while diltiazem pretreatment showed number of electron-dense plaques in the cell membrane and a tendency of decrease in albumin leakage. These results indicate that albumin leakage may be an indirect index of cell wounding in the heart and diltiazem nay be beneficial to protect myocardial cells against isoproterenol-induced cell wounding. It is likely that diltiazem promotes resealing process of the cell membrane.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.1
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• pp.87-98
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• 1999

The objectives of this study were to evaluate exposures to airborne methylene chloride and postshift carboxyhemoglobin (COHb) in blood of workers engaged in processes using blowing or cleaning agents, and to investigate correlation between methylene chloride concentrations and the blood COHb levels of workers. The geometric mean (GM) of workers' exposures (8 hour-time weighted averages, TWA) to airborne methylene chloride during cleaning molds using rags wetted with the solvent in the manufacture of flexible polyurethane foam (GM = 61.4 ppm), during operating the dip tank for cleaning molds in the manufacture of lens (GM = 61.0 ppm), and during cleaning the blowing nozzles by spraying the solvent in the manufacture of shoes (GM = 117.2 ppm) were exceeded the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value ($TLV^{(R)}$)-Time Weighted Average (TWA) (50 ppm). The COHb levels were significantly different among groups (p<0.05). The average COHh levels in blood of non-smoking workers were 2.0% in. low-level (<50 ppm) exposure group, and 3.9 % in high-level (>50ppm) exposure group. The average COHb levels in smoking workers were 3.1% in low-level exposure group, and 4.8% in high-level exposure group. The blood COHb levels of no-exposed workers to methylene chloride were 1.8% in non-smoking group, and 2.8% in smoking group. It was found that the COHb level dependeds on the methylene chloride concentration and smoking habit, and was highly correlated with methylene chloride concentration in air. The correlation coefficient was 0.81 among non-smoking workers. The estimated COHb level (3.6%) and 95% upper confidence limit (4.0%) corresponding to TLV-TWA of methylene chloride exceeded the current ACGIH Biological Exposure Index (COHb 3.5%) for carbon monoxide. The estimated COHb level (5.4%) at 100 ppm exceeded the standard (5%) recommended by National Institute for Occupational Safety and Health (NIOSH) for preventing adverse cardiovascular effect. The estimated COHb value and 95% upper confidence limit at 25 ppm of the Occupational Safety and Health. Adminstration (OSHA) Permissible Exposure Limit-TWA (PEL-TWA) were 2.6% and 3.0%, respectively. It is suggested that COHb in blood be kept below 3.0% to comply with OSHA PEL-TWA.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.1
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• pp.23-40
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• 1999

The analysis of thiodiglycolic acid in urine has been used as an index of biological exposure to vinyl chloride. Unfortunately thiodiglycolic acid has a strong hydrophilic character, because it has two carboxylic groups, so that it can only be extracted with organic solvent with a great difficulty. Underivatized thiodiglycolic acid tends to tail because of non-specific interaction with the inert support. Therefore, esterification is the obvious first choice for derivatization of thiodiglycolic acid, particularly for gas chromatography. In this study, the focus of interest is to compare two method of esterifications (methylation and silylation). Methylation is to make the methyl ester of thiodiglycolic acid by reaction with diazomethane. Silylation is to make the trimethylsilyl ester of thiodiglycolic acid by reaction with N-trimethylsily-ldiethylamine. The results and conclusions are as the following: 1. The detection limit (sensitivity) of methylated thiodiglycolic acid was $5.00{\mu}g/m{\ell}$ and silylated thiodiglycolic acid was $3.07{\mu}g/m{\ell}$ by gas chromatography with flame ionization detector. 2. The optimal liquid-liquid extraction of thiodiglycolic acid was as following: To each of the tubes, $15m{\ell}$ of urine, concentrated sulfuric acid (pH 1 - 2) and 5 gsodium sulfate were added. The samples was extracted three times with $5m{\ell}$ ethylacetate each time. 3. The methylated thiodiglycolic acid was more stable than silylated thiodiglycolic acid in extractional solvent which contained humidity. 4. The precision (pooled coefficient of variation for 4 days) of the analysis was 0.07324 in methylated thiodiglycolic acid with external standard calibration, and 0.07033 in methylated thiodiglycolic acid with internal standard calibration. 5. The precision (pooled coefficient of variation for 4 days) of the analysis was 0.10914 in silylated thiodiglycolic acid with external standard calibration, and 0.13602 in silylated thiodiglycolic acid with internal standard calibration. From the above results, the analysis of methylated thiodiglycolic acid was more sensitive (limit of detection) than silylated thiodiglycolic acid by gas chromatography. However, the methylated thiodiglycolic acid was stable in the humidity and was separated sharply on chromatogram. Also, analysis of methylated thiodiglycolic acid was more precise (pooled coefficient of variation for 4 days) than silylated thiodiglycolic acid. In conclusion, it is established that the analysis of methylated thiodiglycolic acid is appropriate for biological monitoring of exposure to vinyl chloride.

• Toxicological Research
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• v.34 no.3
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• pp.221-229
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• 2018

Tenofovir nanoparticles are novel therapeutic intervention in human immunodeficiency virus (HIV) infection reaching the virus in their sanctuary sites. However, there has been no systemic toxicity testing of this formulation despite global concerns on the safety of nano drugs. Therefore, this study was designed to investigate the toxicity of Tenofovir nanoparticle (NTDF) on the liver and kidney using an animal model. Fifteen adult male Sprague-Dawley (SD) rats maintained at the animal house of the biomedical resources unit of the University of KwaZulu-Natal were weighed and divided into three groups. Control animals (A) were administered with normal saline (NS). The therapeutic doses of Tenofovir (TDF) and nanoparticles of Tenofovir (NTDF) were administered to group B and C and observed for signs of stress for four weeks after which animals were weighed and sacrificed. Liver and kidney were removed and fixed in formal saline, processed and stained using H/E, PAS and MT stains for light microscopy. Serum was obtained for renal function test (RFT) and liver function test (LFT). Cellular measurements and capturing were done using ImageJ and Leica software 2.0. Data were analysed using graph pad 6, p values < 0.05 were significant. We observed no signs of behavioural toxicity and no mortality during this study, however, in the kidneys, we reported mild morphological perturbations widening of Bowman's space, and vacuolations in glomerulus and tubules of TDF and NTDF animals. Also, there was a significant elevation of glycogen deposition in NTDF and TDF animals when compared with control. In the liver, there were mild histological changes with widening of sinusoidal spaces, vacuolations in hepatocytes and elevation of glycogen deposition in TDF and NTDF administered animals. In addition to this, there were no significant differences in stereological measurements and cell count, LFT, RFT, weight changes and organo-somatic index between treatment groups and control. In conclusion, NTDF and TDF in therapeutic doses can lead to mild hepatic and renal histological damage. Further studies are needed to understand the precise genetic mechanism.

• Fire Science and Engineering
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• v.31 no.2
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• pp.17-23
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• 2017

The test methods using convection (flame) and radiation heat sources were compared to evaluate the thermal protective performance of the firefighter's protective clothing. In particular, the influence of the outer shell, mid-layer, and lining constituting the firefighter's protective clothing on the thermal protective performance was compared for convection and radiation heat sources. Tests for the thermal protective performance were carried out according to KS K ISO 9151 (convection), KS K ISO 6942 (radiation), and KS K ISO 17492 (convection and radiation). When tested under the same incident heat flux conditions ($80kW/m^2$), the heat transfer index ($t_{12}$ and $t_{24}$) for the radiation heat source was higher than that for the convection heat source. This means that radiation has a lesser effect than convection. For the convection heat source, the lining had the greatest effect on the thermal protective performance, followed by the mid-layer and the outer shell. On the other hand, for the radiation heat source, the effect on the thermal protective performance was great in the order of lining, outer shell, and mid-layer. Convection and radiation have fundamentally different mechanisms of heat transfer, and different heat sources can lead to different thermal protective performance results depending on the material composition. Therefore, to evaluate the thermal protective performance of the firefighter's protective clothing, it is important to test not only the convection heat source, but also the radiation heat source.

• Journal of Korea Water Resources Association
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• v.45 no.6
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• pp.607-616
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• 2012

The objective of this study is to evaluate the valid forecast lead time and the accuracy when AWS observed rainfall data are used for real-time river flow forecast. For this, Namhan river basin is selected as study area and SURF model is constructed during flood seasons in 2006~2009. The simulated flow with and without the assimilation of the observed flow data are well fitted. Effectiveness index (EI) is used to evaluate amount of improvement for the assimilation. EI at Chungju, Dalcheon, Hoengsung and Yeoju sites as evaluation points show 32.08%, 51.53%, 39.70% and 18.23% improved, respectively. In the results of the forecasted values using the limited observed rainfall data in each forecast time before peak flow occur, the peak flow under the 20% tolerance range of relative error at Chungju, Dalcheon, Hoengsung and Yeoju sites can be simulated in forecast time-11h, 2h, 3h and 5h and the flow volume in the same condition at those sites can be simulated in forecast time-13h, 2h, 4h and 9h, respectively. From this results, observed rainfall data can be used for real-time peak flow forecast because of basin lag time.

• Journal of Preventive Medicine and Public Health
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• v.40 no.6
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• pp.505-511
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• 2007

Objectives : While cervical cancer is one of the leading cancers among women worldwide, there are a number of effective early detection tests available. However, the participation rates in cervical cancer screening among Korean women remain low. After the nationwide efforts in 1988 and thereafter to encourage participation in cervical cancer screening, few studies have investigated the effects of socioeconomic inequality on participation in cervical cancer screening. The purpose of this study was to investigate 1) the level of socioeconomic disparities in receiving cervical cancer screening by age group and 2) if there was an improvement in reducing these disparities between 1995 and 2001. Methods : Using data from the Korean National Health Status, Health Behavior and Belief Survey in 1995, the Korean National Health and Nutrition Examination Surveys from 1998 and 2001 (sample sizes of 2,297, 3,738, and 3,283), age-standardized participation rates were calculated according to education level, equivalized household income, and job status. Odds ratios and the relative inequality index (RII) were also calculated after controlling for age. Results : Women with lower education levels were less likely to attend the screening test, and the disparities by education level were most pronounced among women aged 60 years and older. The RIIs among women 60 years and older were 3.64, 4.46, and 8.64 in 1995, 1998, and 2001, respectively. Higher rates of participation were reported among those in the highest income category, which was more notable among the middle aged women (40s and 50s). An inconsistent trend in the rate of participation in cervical cancer screening by occupational level was found. Conclusions : Indicators of socioeconomic position seem to have varying impacts on the inequalities in the rates of participation in cervical cancer screening according to age group. These results demonstrate the need for more aggressive and age-based interventions and policy programs to eliminate the remaining inequalities.

• Korean Journal of Poultry Science
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• v.42 no.4
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• pp.299-305
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• 2015

The production performance and egg quality traits among five strains of Korean native chickens (KNC) were evaluated in conventional cages. A total of 240 KNC were housed in a controlled environment. Each strain had 12 replicates with 4 chickens per cage. Feed intake, body weights, egg production and egg quality were measured at 24, 28 and 32 of weeks. Egg quality parameters were analyzed using 150 eggs. Results indicated significant (P<0.05) difference in average body weights, egg production and egg weight among five strains of KNC. In contrast, KNC strains effect was non-significant (P>0.05) for feed efficiency. The difference among those KNC strains on egg shell color, egg shell strength and egg shell density were not different (P>0.05) at the age of week 24 while it was significant (P<0.05) at the age of week 28 and 32. There was no effect (P>0.05) on egg length and egg shape index from five strains of KNC. The significant difference (P<0.05) was observed in egg width with KNC strains during early ages (week 24 and 28) and it was not significant (P>0.05) at the age of 32 weeks. Regarding internal quality parameters, albumen height and Haugh unit were significantly (P<0.05) affected with KNC strains while the effect on yolk color was not significant (P>0.05). Based on the egg weight and the production performance, GS-10 KNC strain was superior when compared with the other strains.