• Journal of Environmental Health Sciences
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• v.32 no.5 s.92
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• pp.506-514
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• 2006

The objectives of this study were to evaluate personal exposure estimated using a time activity pattern and microenvironmental model. The study was carried out for 44 children attending a primary school nearby the lines (school A) and 125 children attending a school away from 154 kV power lines (school B). For children attending school A, the estimated personal level was a little weak correlated with the measured level($Pearson\;r\;=0.34{\sim}0.35$). For children attending school B, the correlation was very low ($Pearson\;r\;=\;0.09{\sim}0.16$) using the TW A Model II, otherwise, TWA Model II-I which considered the average residential MF level according to the distance from the power line and home explained $39{\sim}53%$ of the correlation in MF personal exposures. The estimated personal exposure level was very well represented by the measured exposure level using TWA Model II-2 which consisted on spot and 24 h stationary measurements at subject's home ($Pearson\;r\;=\;0.65{\sim}0.85$). In conclusion, personal magnetic field expsoure estimated using a TWA Model II-2 should be provided for a reasonable estimate of measured exposure in schoolchildren living near the power line.

• Archives of Plastic Surgery
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• v.37 no.1
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• pp.26-30
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• 2010

Purpose: Common complications of immediate breast reconstruction with implant are capsular contracture, malposition of implant, hematoma and seroma. Especially, the most severe complication is implant exposure caused by inflammation or necrosis of skin flap margin of mastectomy site. This article reports the experience of cases of salvage in such an exposure of implant. Methods: From July, 2002 to Feb., 2009, sixty-five patients who underwent immediate breast reconstruction with implant were retrospectively analyzed. Exposure of implant was happened in 5 of 65 patients and they were treated at out patient district. Two of five patients were reconstructed with saline implnt and all of them underwent the enveloping of the implant with AlloDerm$^{(R)}$ and Serratus muscle flap. Remaning three patients were reconstructed with silicone implant and all of them underwent the enveloping of the implant with AlloDerm$^{(R)}$. Results: In the group of patients who underwent reconstruction with saline implant, implant exposure was found in one patient due to partial necrosis of the margin of skin flap and debridement and primary repair were done. In the other one patient, dressing with antibiotic ointment were done. And debridement and primary repair were proceeded. In the group of patients who underwent reconstruction with silicone implant, implant exposure was found in one patient. After removal of the implant, tissue expansion was done and a new silicone implant was inserted. Implant exposure were found in the other two patients, antibiotics ointment application and primarily repaired. Conclusion: It was the common knowledge that the exposed implant should be removed. But salvage of the exposed implants may be possible with proper treatment. Four of five patients (80%) with exposed breast implant were salvaged with conservative management.

• Journal of Periodontal and Implant Science
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• v.35 no.1
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• pp.65-76
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• 2005

This retrospective study evaluates the clinical performance of the recently introduced $XiVE^{(R)}$ implant(Dentsply-Friadent) with a new macro-design to improve primary stability. A total of 208 $XiVE^{(R)}$ implants (101 in the maxilla and 107 in the mandible) were placed in 71 patients. The average age of the patients was 49 years. Of the 208 implants, 190 (91.3%) were posterior implants and 82 (39.4%) were placed in compromised sites (grafted sites). Clinical and radiographic evaluation were made at second stage surgery for exposure and after functional loading. 192 implants in 64 patients were evaluated at exposure and 146 implants in 50 patients were loaded (average 170 days-loading) and evaluated after functional loading. Of 192 implants available for evaluation before loading, 3 implants failed (early failure) ; 1 before exposure, 1 at exposure and 1 during prosthetic procedure. 2 implants were in the maxilla and 1 was in the mandible. The success rate before loading was 98.4%. After functional loading, no implant failure was occurred in 146 implants evaluated during this period (100% interval success rate). This preliminary data with a new implant showed excellent success rate although the majority of implants evaluated in this study were placed in the posterior region of the jaw and compromised sites.

• Safety and Health at Work
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• v.7 no.4
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• pp.372-380
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• 2016

Background: The aim of this study was to estimate the number of workers exposed to diesel engine exhaust (DEE) by industry and year in the Republic of Korea. Method: The estimates of workers potentially exposed to DEE in the Republic of Korea were calculated by industry on the basis of the carcinogen exposure (CAREX) surveillance system. The data on the labor force employed in DEE exposure industries were obtained from the Census on Establishments conducted by the Korea National Statistical Office from 1993 to 2013. The mean values of prevalence rates adopted by EU15 countries were used as the primary exposure prevalence rates. We also investigated the exposure prevalence rates and exposure characteristics of DEE in 359 workplaces representing 11 industries. Results: The total number of workers exposed to DEE were estimated as 270,014 in 1993 and 417,034 in 2013 (2.2% of the total labor force). As of 2013, the industry categorized as "Land transport" showed the highest number of workers exposed to DEE with 174,359, followed by "Personal and household services" with 70,298, "Construction" with 45,555, "Wholesale and retail trade and restaurants and hotels" with 44,005, and "Sanitation and similar services" with 12,584. These five industries, with more than 10,000 workers exposed to DEE, accounted for 83% of the total DEE-exposed workers. Comparing primary prevalence rates used for preliminary estimation among 49 industries, "Metal ore mining" had the highest rate at 52.6%, followed by "Other mining" with 50.0%, and "Land transport" with 23.6%. Conclusion: The DEE prevalence rates we surveyed (1.3-19.8%) were higher than the primary prevalence rates. The most common emission sources of DEE were diesel engine vehicles such as forklifts, trucks, and vans. Our estimated numbers of workers exposed to DEE can be used to identify industries with workers requiring protection from potential exposure to DEE in the Republic of Korea.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.4
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• pp.334-345
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• 2006

The objectives of this study were to analyze and compare 24 hrs personal exposure levels of MF at microenvironments such as home, school, educational institute, internet pc game room, transportation, and other places according to time activity patterns using various metrics for children attending the primary schools located near and away from the power lines, and to characterize the major microenvironments and impact factors attributed personal exposure level. The study was carried out for 44 children attending a primary school away from the lines(school A) and 125 children attending a school away from 154 kV power lines(school B), all who aged 12 years and were 6 grade, from July 2003 to December 2003. All participants filled in a questionnaire about characteristics, residence, use of electrical appliances and others. Children wore a small satchel in which EMDEX II and Lite (Enertech, Co. Ltd) and a diary of activity list for period of registration in 20 minutes blocks. All statistical calculations were made with the SAS System, Releas 6.12. The summary of results was presented below. First, about the characteristics of subjects, there no differences between two groups. The subject almost spent about 56 % of their time at home and about 20~25 % of their time at school. Fifty percent of children spent 2 hours at private educational institutes. Second, the personal exposure measurements of children in school B was statistically higher than those of children in school A by various metrics such as arithmetic mean, geometric mean, percentile(5, 25, 50, 75, 95), maximum, rate of change metric, constant field metric. The arithmetic and geometric mean magnetic fields during the time the children were at school B were 0.98 and $0.86{\mu}T$ and were about 23 times higher than those of children were at school A. In conclusion, the significant major determinants of personal exposure level is the distance from the power line to microenvironments.

• Safety and Health at Work
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• v.10 no.3
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• pp.389-392
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• 2019

When conducting an exposure assessment, the primary goal of the industrial hygienist is to fully characterize the worker's exposure during a work shift to compare it with an occupational exposure limit. This applies regardless of the duration of the work activity as an activity that is relatively short in duration can still present exposure in excess of the occupational exposure limit even when normalized over an 8-hr shift. This goal, however, is often impeded by the specification of a minimum sample volume in the published sampling method, which may prevent the sample from being collected or submitted for analysis. Removing the specification of minimum sample volume (or adjusting it from a requirement to a recommendation), in contrast, allows for a broader assessment of jobs that consist of short-duration and high-exposure activities and also eliminates the unnecessary practice of running sampling pumps in clean air to collect a specified, minimum volume.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.2
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• pp.145-157
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• 1999

Wood dust is created when machines are used to cut or shape wood materials. Industries of high risk of wood dust exposure are sawmills, dimension mills, furniture industries, and carpenters, etc. Health effects associated with wood dust exposure includes dermatitis, allergic respiratory effects and cancer. Health effects of wood dus t are mainly depend on the concentration, dust size and exposure time. This study were carried out to evaluate the concentration and particle size distribution of wood dust during working processes. The subjects of this study were 53 workers exposed to wood dust in 7 furniture factories and 5 musical instruments, and 5 sawmill factories. The average total wood dust concentrations measured by personal cascade impactor were $1.82{\pm}2.31mg/m^3$ in primary manufacture, $3.59{\pm}1.72mg/m^3$ in s econdary manufacture, $5.09{\pm}1.46mg/m^3$ in sanding operation. Mass median diameters of hardwoods dust were $3.36{\mu}m$ in primary manufacture, $4.25{\mu}m$ in secondary manufacture, $4.21{\mu}m$ in sanding operation. softwoods dust were $3.39{\mu}m$ in primary manufacture, $4.34{\mu}m$ in secondary manufacture. Particle size distributions showed a nearly the same pattern in each working processes. The sample concentration of all hardwood dust exceeded the Threshold Limit Value(TLV) and 20.8% of the softwood dust exceeded the Threshold Limit Value. The range of size distribution were $0.5-10{\mu}m$ in the soft and hardwood dust. The respirable dust of soft and hardwood took up 59% and above. Therefore new threshold limit value for wood dust should be needed in Korea. Also, it should be done for various studies on health effects related to occupational exposure of wood dust.

• YAKHAK HOEJI
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• v.38 no.4
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• pp.401-409
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• 1994

The cholinergic activity of dammarane glycosides of Panax ginseng was examined both morphologically and chemically on primary cultures of chicken embryonic brain cells. When primary cultured chicken embryonic cells were treated with $50\;{\mu}g/ml$ of total dammarane glycosides of Panax ginseng followed by the exposure to 10mM atropine for 48 hr, lactate dehydrogenase levels within the cells remained at 36% of untreated control values while atropine-treated controls fell to 0% lactate dehydrogenase. It was found that cholinergic activity was mainly exerted by the panaxadiol glycosides. The treatment of the cells with $50\;{\mu}g/ml$ of panaxadiol glycosides followed by the exposure to atropine, lactate dehydrogenase levels within the cells remained at 60% of untreated control values. Ginsenoside $Rb_1$, a component of panaxadiol glycosides, was found to exert the cholinergic activity keeping the lactate dehydrogenase levels within the cells at 70% of untreated control values. The cholinergic activity of ginsenoside $Rb_1$ seems to be exerted through acting on the $Ca^{2+}$ channel in cultured brain cells.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.404-406
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• 2002

We have investigated the contribution of the scattered x rays to the signal imaging in the radiographs acquired with anti-scatter grids of several grid ratios by separating the line spread functions (LSFs) derived from the signal edge image into the primary and the scatter components. By using a 1.0-mm lead plate in the scattering material, the blurred signal edge images were acquired by use of an imaging plate at a tube voltage of 80 kV with the anti-scatter grids of grid ratios for 5:1, 6:1, 8:1, 10:1 and 12:1. The edge profiles of the signal images were scanned and those in relative exposure were differentiated to obtain the LSFs. To investigate the contribution of the scattered x rays to the signal imaging, we proposed a method for separating the LSFs derived from the signal images into the primary and the scatter components, where the scatter component was approximated with exponential function. Our basic approach is to separate the area of the LSFs by ratios of the scattered x-ray exposure to the primary x-ray exposure, which were obtained for the grid ratios by use of a lead disk method. The LSFs and the two components were Fourier transformed to obtain the modulation transfer functions (MTFs) and their two components. As the result, we found that, by using the anti-scatter grids, the scattered x rays were reduced, but the shape of the LSFs of the scatter component hardly changed. The contributions of the scatter component to the MTFs were not negligible (more than 10 %) for spatial frequencies lower than about 1.0 mm$\^$-l/ and that was greater as the grid ratio decreasing. On the other hand, for higher frequencies, the primary component was dominant compared with the scatter component.

• Journal of Environmental Health Sciences
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• v.50 no.1
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• pp.43-53
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• 2024

Background: Exposure assessment is an important part of risk assessment for consumer products. Exposure models are used when estimating consumer exposures by considering exposure routes, subjects, and circumstances. These models differ based on their tiers, types, and target populations. Consequently, exposure estimates may vary between models. Objectives: This study aimed to compare the results of different exposure models using identical exposure factors. Methods: Chemical exposure from consumer products was calculated using four consumer exposure assessment models: Targeted Risk Assessment 3.1, Consumer Exposure Model 2.1 (CEM), ConsExpo web 1.1.1, and the Korean Exposure Algorithm (primary and detailed) issued by the Ministry of Environment, No. 972 (MOE). The same exposure factors were used in each model to calculate inhalation and dermal exposures to acetaldehyde, d-limonene, and naphthalene in all-purpose cleaners, leather coating sprays, and sealants. Results: In the results, TRA provided the highest estimate. Generally, MOE (detailed), CEM and ConsExpo showed lower exposures. The inhalation exposure for leather coating spray showed the largest differences between models, with differences reaching up to 1.2×10⁷ times. Since identical inputs were used for the calculations, it is likely that the models significantly influenced the estimated results. Conclusions: Despite using the same exposure factors to calculate dermal and inhalation exposures, the results varied substantially based on the model's exposure algorithm. Therefore, selecting an exposure model for assessing consumer products should be done with careful consideration.