• Journal of Environmental Health Sciences
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• v.31 no.6
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• pp.475-482
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• 2005

This study aimed to determine the fluoride intakes in 120 preschool children aged 3 to 6 residing in Jumunjin (community water fluoridation area) and Gangneung (non-fluoridation area). The parents were asked to collect 24-hour urine samples and to duplicate the samples of all the diets that their children ingested in the day of urine collection. The acid-diffusible fluoride in the food and non-carbonate beverages were isolated by the acid-diffusion technique and then measured with a fluoride electrode. The fluoride in carbonate beverages, drinking waters and urine samples were measured directly with a fluoride electrode. The geometric mean (geometric standard deviation) of daily fluoride intakes from all kinds of diet was 5.99 (2.27) $\mu$g/kg/day in the children in Gangneung and that of the children in Jumunjin was 18.36 (2.69). The amount of fluoride intake by food and drinking water in fluoridation area were significantly larger than that in non-fluoridation area but the statistical difference of fluoride intake by beverages between two areas was not observed. The GMs (GSDs) of daily fluoride excretion by urine of children in non-fluoridation area and in fluoridation area were 8.39 (1.73) and 18.62 (1.77) $\mu$g/kg/day, respectively. The correlation between fluoride intake from diet excluding beverage and urinary excretion was statistically significant. It is concluded that the amount of fluoride intake of children living in fluoridation area did not exceed the upper intake level to avoid the risk of dental fluorosis (2.2 mg/day in 4- to 8-year-olds) and urinary excretion of fluoride was good indicator of fluoride intake from diets.

• Asian Journal of Atmospheric Environment
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• v.6 no.4
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• pp.304-313
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• 2012

In this study, the ${\AA}$ngstrom exponent for polydispersed aerosol during dynamic processes was investigated. Log-normal aerosol size distribution was assumed, and a sensitivity analysis of the ${\AA}$ngstrom exponent with regards the coagulation and condensation process was performed. The ${\AA}$ngstrom exponent is expected to decrease because of the particle growth due to coagulation and condensation. However, it is difficult to quantify the degree of change. In order to understand quantitatively the change in the ${\AA}$ngstrom exponent during coagulation and condensation, different real and imaginary parts of the refractive index were considered. The results show that the ${\AA}$ngstrom exponent is sensitive to changes in size distribution and refractive index. The total number concentration decreases and the geometric mean diameter of aerosols increase during coagulation. On the while, the geometric standard deviation approaches monodispersed size distribution during the condensation process, and this change in size distribution affects the ${\AA}$ngstrom exponent. The degree of change in the ${\AA}$ngstrom exponent depends on the refractive index and initial size distribution, and the size parameter changes with the ${\AA}$ngstrom exponent for a given refractive index or chemical composition; this indicates that the size distribution plays an important role in determining the ${\AA}$ngstrom exponent as well as the chemical composition. Subsequently, this study shows how the ${\AA}$ngstrom exponent changes quantitatively during the aerosol dynamics processes for a log-normal aerosol size distribution for different refractive indices; the results showed good agreement with the results for simple analytic size distribution solutions.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.10a
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• pp.150-150
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• 2003

The objective of this study was to describe the distribution of metals concentrations in blood of adults who were not occupationally exposed in Korea. The blood samples were obtained between February and August 2001 from volunteer adults in urban area of Korea. 66 male participants were 46 (20-75) years of age and 74 female were 40 (20-69) years of age. The levels of metals in blood were observed the log-normal distribution, and we calculated geometric mean (GM) and geometric standard deviation (GSD). The GM levels of metals in blood of the men were 65.88$\mu\textrm{g}$/$\ell$, 1.01$\mu\textrm{g}$/$\ell$, 0.23$\mu\textrm{g}$/$\ell$ and 0.15$\mu\textrm{g}$/$\ell$, for Pb, Cr, Ni and Cd, respectively. The GM levels of the women were 58.49$\mu\textrm{g}$/$\ell$, 1.66$\mu\textrm{g}$/$\ell$, 0.30$\mu\textrm{g}$/$\ell$ and 0.10$\mu\textrm{g}$/$\ell$, for Pb, Cr, Ni and Cd, respectively. The levels of Pb-B and Cd-B were significantly higher non-smoker than smoker, whereas those of Cr-B and Ni-B were not different by smoking habit.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.3
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• pp.261-269
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• 2005

To investigate the field applicability of a diffusive sampler (3M OVM #3500, passive sampling method) authors conducted a simultaneous measurement of personal organic solvents exposure in the air of the workplaces by charcoal tube with low volume sampler (active sampling method) and diffusive sampler. Samples were collected and analyzed by NIOSH method ($NMAM^{(R)}$) from thirty-eight workers in 12 factories who work in 6 different processes. Geometric mean (GM) and geometric standard deviation (GSD) were used to describe the result. To compare the results of the two methods, paired t-test was used. According to the manual of the exposure assessment of the mixed organic solvents (Ministry of Labor, Korea), Em was calculated. Simple linear regression was used to evaluate the relationship between the two methods. Results were as follows; 1. Eight different solvents (ethyl acetate, n-hexane, toluene, xylene, acetone, isopropyl alcohol, methyl ethyl ketone (MEK), and methyl isobutyl ketone) were detected simultaneously in the two methods and the concentrations of the personal exposure were lower than 0.5 TLV level. The concentration of the charcoal tube method was higher than that of a diffusive sampler in n-hexane and MEK (p<0.05). 2. Em of the charcoal tube method was higher than that of diffusive sampler method but not significantly different and was lower than the OEL (Occupational Exposure Limit) in all 6 processes. 3. There was a significant correlation between the two methods in low concentrations of the 8 organic solvents (p<0.05). In conclusion, there was no difference in charcoal tube method and diffusive sampler method in low concentrations of some organic solvents, diffusive sampler can be applied to assess the personal monitoring in low level exposure.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.3
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• pp.163-169
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• 2017

Objectives: This study was conducted toestimate quartz concentrations and contents in the airborne respirable dust from various industries. Methods: A total of 818 samples were collected from 174 industries. Respirable dust samples were collected using a cyclone equipped with a 37 mm, $5{\mu}m$ pore size PVC filter. The quartz concentrations were identified using the intensity of the absorption peak of quartz at $799cm^{-1}$ by Fourie Transformed Infrared Spectroscopy(FTIR). Results: The respective geometric means for quartz concentrations in the respirable dust were 0.0050, 0.0049, 0.0025, and $0.0019mg/m^3$ in foundries, ceramics, construction, and cement/stone. The geometric mean of quartz contents analyzed by FTIR were respectively 3.43, 1.99, 1.04, and 0.82% for ceramics, foundries, cement/stone, and construction. The rate of exceeding the Korean Occupational Exposure Limit($0.05mg/m^3$) was 2.03%, but rate of exceeding the American Conference of Governmental Industrial Hygienist(ACGIH) Threshold Limit Value($0.025mg/m^3$) was 7.12%. Conclusions: Given that foundries had a higher quartz concentration, there is a need to reduce respirable dust, such as through wet operation. In order to protect the health of workers exposed to mineral dust, it is necessary to actively consider strengthening the Korean Occupational Exposure Limit.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.2
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• pp.194-201
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• 2015

Objectives: The purpose of this study is to assess the exposure level to dust and airborne microorganisms among employed workers in a clothing shopping center. Materials and Methods: On-site investigation of a clothing shopping center was performed between October and November 2012. The hazardous substances measured in this study are particulate matter(Total dust, respirable dust) and airborne microorganisms (Total airborne bacteria, total airborne fungi). Results: The highest geometric mean levels of particulate matter(total dust, respirable dust) for personal sampling were $1.735(SD:0.883)mg/m^3$ for total dust and $0.0711(SD:0.008)mg/m^3$ for respirable dust, respectively. Those for area sampling were $0.625(SD:0.091)mg/m^3$ for total dust and $0.0718(SD:0.012)mg/m^3$ for respirable dust, respectively. The highest geometric averaged concentrations of airborne microorganisms(Total airborne bacteria, total airborne fungi) were detected at $1,181(SD:105)cfu/m^3$ for total airborne bacteria and $683(SD:114)cfu/m^3$ for total airborne fungi, respectively. Concentrations of particulate matters and airborne microorganism in clothes shopping center did not correlate significantly with environmental factors such as temperature or relative humidity. Conclusions: Exposure levelshave not been established for service workers. Thus, health risk assessment for this group is very difficult. Health guidelines for service workers should be established as soon as possible.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.4
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• pp.488-499
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• 2019

Objectives: This study was conducted to identify the characterization of organics solvent exposure among painting workers in the shipbuilding painting process, especially for their daily variations(within worker variance). Methods: Charcoal passive dosimeters were worn throughout each work shift for 20 days for five painting workers from October 19 to November 26, 2015. A total of 100 samples were collected, analyzed and compared with statutory workplace environmental measurements. Results: The geometric mean(GM) and geometric standard deviation(GSD) of mixed organic solvent(six substances) exposure index(EI) for the 100 samples were 0.42 and 4.42 respectively. The median and range of GSD for within worker EI representing five workers' daily EI variation is 3.72 and 2.63 ~ 5.20, respectively, which is classified as a very large variation(GSD>3). We were able to divide the painting process into two similar exposure groups(SEGs), Touch-up and Spray. Spray painting workers were much more exposed to organic solvent than Touch-up painting workers(GM=0.71 vs. 0.19), but less variably (GSD=3.64 vs. 4.10). xylene is the substance to which the workers were most exposed(GM=16.19 ppm, GSD=4.36), and the exposure characteristics of six substances including xylene is similar to those of EI. Conclusions: The daily variation of organic solvent exposure in the shipbuilding painting process is so high that statutory Assessment of Reliability of Work Environment Monitoring needs to be conducted with statistically sufficient number of samples and evidence.

• Selected Papers of The Society of Naval Architects of Korea
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• v.1 no.1
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• pp.76-90
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• 1993

A new propeller series is developed using the newly developed blade section (KH 18 section) which has better cavitation characteristics and higher lift-drag ratio at wade angle-of-attack range than a conventional section. The radial patch distribution of the new series propellers is variable stance they were designed adaptively to a typical wake distribution. Basic geometric particulars of the series propellers. such as chord length, thickness, skew and rake distributions, are determined on the basis of recent full scale propeller geometric data. The series is developed for propellers having 4 blades, and blade area ratios of 0.3, 0.45, 0.6 and 0.75. Mean pitch ratios are varied as 0.5, 0.6, 0.7, 0.95 and 1.1 for each blade area ratio. The new propeller series consists of 20 propellers and is named as the KD(KRISO-DAEWOO)-propeller series. Propeller open-water tests are performed at the towing tank, and cavitation observation tests and fluctuating pressure tests are carried out at the cavitation tunnel of KRISO. $B_{p}-\delta$ curves, which can be used to select the optimum propeller diameter at the preliminary design stage, are derived from a regression analysis of the propeller open-water test results. The KD-cavitation chart is derived from the cavitation observation test results by choosing the local maximum lift coefficient and the local cavitation number as parameters. The cavity extent predicted by the KD-cavitation chart would be more accurate compared to that by an existing cavitation charts, such as the Burrll's cavitation chart, since the former is derived from the cavitation observation test results in a typical ship's wake, while the lather is derived from the test results in a uniform flow.

• The Research Journal of the Costume Culture
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• v.12 no.1
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• pp.59-72
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• 2004

The objectives of this study were to investigate the perceptions of Korean female university students for clothing pattern tendency and structural element of clothing pattern image dimension and to find how individual personality type influence the preferred clothing pattern characteristics. For this study, a questionnaire was designed and sent to 600 female university students of Daejeon, Seoul and metropolitan area. The tool used in this study was MBTI(The Myers-Briggs Type Indicator) Form G Korean version and for the analysis of data SPSS 10.0 package were used. 10 representative patterns for this study were floral, dot, stripe, check, animal, abstract & artistic, geometric, vegetable & leaf, paisely, patchwork pattern. The data were analyzed by factor analysis, arithmetic mean, One-Way ANOVA, x²-test. The major findings were as follows: Clothing pattern image dimension perceived by Korean female university students for 10 representative patterns were basic form, deluxe, specialty, and cultural dimension. Among them, basic form and deluxe dimension were major dimensions. In basic form dimension, dot pattern score was high indicating female students perceive it as light, comfortable, clean, cool and simple pattern image. In deluxe dimension, floral pattern scored high and in specialty dimension, abstract and artistic pattern scored high among other pattern image. In cultural dimension, geometric pattern and check pattern scored high. Based on other detailed analysis results, It is concluded that the personality type greatly influence clothing pattern evaluation. For example, in case of color combination of patchwork pattern, there was a difference in color preference depend on a personality type such as sensing(S) or intuition(N). Therefore, sensing personality type preferred adjacent color combination than contrast color combination. Detailed marketing strategy is necessary in planning textile design of merchandise plan.

• Archives of Pharmacal Research
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• v.28 no.4
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• pp.488-492
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• 2005

The purpose of this study is to investigate the bioequivalence of two haloperidol 5 mg tablets, Myung In haloperidol (Myung In Pharm. Co., Ltd., test drug) and $Peridol^{R}$(Whanin Pharm. Co., Ltd., reference drug), and also to estimate the pharmacokinetic parameters of haloperidol in Korean volunteers. The bioavailability and pharmacokinetics of haloperidol tablets were examined on 24 healthy volunteers who received a single oral dose of each preparation in the fasting state in a randomized balanced 2 way crossover design. After an oral dosing, blood samples were collected for a period of 60 h. Plasma concentrations of haloperidol were determined using a liquid chromatographic electrospray mass spectrometric (LC-MS) method. The pharmacokinetic parameters were calculated with noncompartmental pharmacokinetic analysis. The geometric means of $AUC_{0-60h} and C_{max}$ between test and reference formulations were $17.21\pm8.26 ng\cdot/mL vs 17.31\pm13.24 ng\cdot/mL and 0.87\pm0.74 ng/mL vs 0.85\pm0.62 ng/mL$. respectively. The $90\%$ confidence intervals of mean difference of logarithmic transformed $AUC_{0-60h} and C_{max} were log0.9677{\sim}log1.1201 and log0.8208{\sim}log1.1981$, respectively. It shows that the bioavailability of test drug is equivalent with that of reference drug. The geometric means of other pharmacokinetic parameters ($AUC_{inf}. t_{1/2}, V_{d}/F, and CL/F$) between test drug and reference drug were $21.75\pm8.50 ng{\cdot}h/mL vs 21.77\pm15.63 ng{\cdot}h/mL, 29.87\pm8.25 h vs 29.60\pm7.56 h, 11.51\pm5.45 L vs 12.90\pm6.12 L and 0.26\pm0.09 L/h vs 0.31\pm0.17 L/h$, respectively. These observations indicate that the two formulation for haloperidol was bioequivalent and, thus, may be clinically interchangeable.