• Journal of the East Asian Society of Dietary Life
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• v.21 no.3
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• pp.451-462
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• 2011

The purpose of this study was to examine the level of concern and the level of knowledge of endocrine disruptors, and the level of dietary behaviors to decrease exposure to endocrine disruptors, to determine the factors affecting the level of knowledge and behaviors, and to assess the causal relationship between them. The data were collected from 579 adults in Seoul, Incheon, Daejeon, Daegu, Busan and Gwangju provinces. Frequencies, t tests, analysis of variance, Cronbach's alpha, Pearson's correlation coefficient analysis, multiple regression analyses, and path analysis were carried out by SPSS for Win V.18.0. The results of this study were as follows: The level of concern about endocrine disruptors was higher than the medium level. The respondents were most concerned about a container of cup ramen among products related to foods. The levels of both knowledge and behaviors in order to decrease exposure to endocrine disruptors in dietary life were not high. The factors affecting the level of knowledge of endocrine disruptors were educational level, attendance in education for endocrine disruptors, and concern about endocrine disruptors. On the other hand, sex, age, concern about endocrine disruptors, and the level of knowledge of endocrine disruptors affected the level of behaviors to decrease exposure toward endocrine disruptors. The results of the path analysis showed that educational level and education of endocrine disruptors had an indirect influence on the level of behaviors in order to decrease exposure to endocrine disruptors in dietary life. The concern about endocrine disruptors had both a direct and an indirect effect on the level of behaviors to decrease exposure to endocrine disruptors in dietary life. In addition, sex, age and the level of knowledge of endocrine disruptors directly affected the level of behaviors to decrease exposure to endocrine disruptors in dietary life.

• Journal of the Korean Society of Radiology
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• v.17 no.6
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• pp.851-857
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• 2023

The purpose of this study is to investigate the effect of changes in collimation size and sub ROI on exposure index(EI) in hand radiography, present collimation size and EI suitable for average hand size of Koreans, and present the effect of changes in sub ROI on EI. The subjects of this study were hand-wrist phantom, and the exposure conditions were set to 55 kVp, 125, mA, and 6.25 mAs, and source to image receptor distance was applied to 110 cm. Based on the vendor recommended sub-ROI (18.7" × 18.7", 8" × 10", 8" × 7.4", 6" × 7.4")and the textbook's recommended sub-ROI 8" × 10", each obtaining 30 images, and comparing the EI shown in the equipment. The EI according to the change in the size of the collimation were 1663.7±4.52, 8"×10" is 1489.1±4.49, 8"×7.4" is 1716.9±3.00, 6"×7.4" is 168.7±3.66 for each EI, and the average value of each value was statistically significant. The average EI according to the sub ROI change was 1489.1±4.49 for SS, LS was 1694.8±5.19 for AEC, 2052.9±5.96, VR was 1548.3±3.20, and HR was 1663.2±4.33. The appropriate field size considering the hand size of Koreans was found to be 8"×7.4". In addition, when the field size increases based on the generally known field size (8"×10") during hand radiography, the EI value changes from a maximum of 15% to a minimum of 11%, and the sub ROI shape based on sub ROI 'SS' Depending on the change, the EI value increased from a maximum of 37% to a minimum of 3%.

• Archives of Reconstructive Microsurgery
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• v.10 no.1
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• pp.55-59
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• 2001

The hand is a frequently affected area in high voltage electrical burn injury as an input or output sites. Therefore, early debridement and synchronous flap coverage are generally accepted as a primary treatment of several electrical burns complicated by exposure of tendons, neurovascular structures, and bones. So, in order to establish convenient, promising methods for the reconstruction of hand defects in electrical burn patients, we performed various reverse forearm flaps. From March 1997 to February 2000, we reconstructed 12 cases of hand defects in high voltage electrical burn wounds with reverse forearm flaps. Reverse radial fasciocutaneous flap were 3 cases, reverse ulnar fasciocutaneous flap were 3 cases, reverse ulnar fasciocutaneous flap and STSG were 4 cases, reverse ulnar fascial flap and STSG were 2 cases. We successfully reconstructed hand defects in all 12 cases, and obtained following conclusions. 1 Various reverse forearm flaps provide well vascularized, profitable tissues and they require short operative time with relatively easy procedures. 2. Reverse fascial flap and STSG, reverse fasciocutaneous flap and STSG provide thin flaps with good aesthetics and minor donor site morbidity.

• Archives of Reconstructive Microsurgery
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• v.9 no.1
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• pp.37-43
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• 2000

Vascularized tissue coverage is necessary for treatment of soft tissue defect with bone and tendon exposure on hand and foot dorsum, which cannot be successfully covered with simple skin graft or local flap. The temporal fascia is one of the most ideal donor for coverage of soft tissue defect of dorsum of hand or foot in term of ultra-thin, pliable and highly vascular tissue. Also, this flap offers the advantage of a well-concealed donor site in the hair-bearing scalp and smooth tendon gliding. We have experienced 11 cases of reconstruction for soft tissue defect in the hand or foot using temporal fascial flap with skin graft. All cases survived completely and we could gain satisfactory functional results. There were no specific complications except one donor site alopecia We think that the free temporal fascial flap coverage is a highly reliable method for soft tissue defect in hand and foot dorsum. However, the potential pitfalls is secondary alopecia and requirement of skin graft after its transfer.

• Journal of Environmental Health Sciences
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• v.46 no.3
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• pp.335-343
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• 2020

Objectives: The Korean Ministry of Environment has identified cases of people suspected of suffering lung disease potentially caused by polyhexamethylene guanidine (PHMG) used in humidifier disinfectants (HDs). Exposure assessment for the HDs was conducted using a questionnaire during face-to-face interview. The main purposes of this study were to develop a methodology to effectively classify levels of exposure to HDs based on a questionnaire. Methods: We first identified the overall participants' exposure characteristics by HD exposure levels; Second, we selected misclassified subjects and investigated characteristics of overestimated and underestimated subjects, focusing on exposure cases to PHMG-containing HDs. An inhalation reference concentration (RfC) for PHMG was produced on the basis of inhalation toxicity values. We made a cross-tabulation of the exposure classes (Exposure classes 1-to-4) by clinical classes based on the RfC. When the value of the exposure class minus the clinical class was 0 or 1, we assumed these were true values. When the value was ≥2 and ≤ -2, we assigned these cases to the overestimation group and underestimation group, respectively. Results: The overestimated group may have already recovered and responded excessively due to psychological anxiety or in order to receive compensation. On the other hand, relatively high mortality rates and surrogate responses for those under 10 years of age may have resulted in inaccurate exposure assessment for underestimated groups. For the characteristics of exposure, it was shown that for the underestimated group, the exposure was relatively weaker than the overestimated group, even though a high overall clinical rating was determined. Conclusions: This study may suggest ways to reduce bias and overcome the limitations of current HD exposure assessment.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.2
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• pp.53-59
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• 2017

In this experimental study, the characteristic of damages on GFRP rebar exposed to high temperature only and immerged in alkaline solution after the exposure to high temperature was analyzed through microscopic image analysis. The found microcrack and pores in resin matrix were quantitatively compared if there was effect of pre-exposure to high temperature. The damages, such as microcrack and pores in resin matrix, by alkali exposure were mainly found in rebar surface. On the other hand, the pores caused by high temperatures were extensively found in a section and had greater width than those caused by the alkali exposure. In results of the quantitative comparison, the accumulated length and widths of microcrack and pores in resin matrix in pre-exposed GFRP rebar to high temperature were respectively 1.5 and 1.4 times of those in the GFRP rebar only immerged in alkali solution. Therefore, the deterioration of resin matrix by the alkali exposure could be accelerated due to the pre-exposure to high temperature.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.25 no.2
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• pp.59-75
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• 1999

Skin is continuously exposed to external stimuli including ultraviolet radiation, which is a major cause of skin photoaging. According to recent discoveries, UVA with a lower energy but deep-penetrating properties, compared to UVB, is likely to play a major part in causing skin photoaging. The clinical and histochemical changes of photoaging are well characterized, but the biochemical mechanisms are poorly understood partly due to the lack of suitable experimental systems. In this work, three-dimensional, reconstituted skin culture models were prepared. After certain period of maturation, the equivalent models were shown to be similar in structure and biochemical characteristics to normal skin. Mature dermal and skin equivalent models were exposed to sub-lethal doses of UVA, and the effects of UVA relevant to dermal photoaging were monitored, including the production of elastin, collagen, collagenase(MMP-1), and tissue inhibitor of metalloproteinases-1 (TIMP-1). Interestingly, dermal and skin equivalents reacted differently to acute and chronic exposure to UVA. Elastin production was increased as soon as one week after commencing UVA irradiation by chronic exposure, although a single exposure failed to do so. This early response could be an important advantage of equivalent models in studying elastosis in photoaged skin. Collagenase activity was increased by acute UVA irradiation, but returned to control levels after repeated exposure. On the other hand, collagen biosynthesis, which was increased by a single exposure, decreased slightly during 5 weeks of prolonged UVA exposure. Collagenase has been thought to be responsible for collagen degeneration in dermal photoaging. However, according to the results obtained in this study, elevated collagenase activity is not likely to be responsible for the degeneration of collagen in dermal photoagig, while reduced production of collagen may be the main reason. It can be concluded that reconstituted skin culture models can serve as useful experimental tools for the study of skin photoaging. These culture models are relatively simple to construct, easy to handle, and are reproducible Moreover the changes of dermal photoaging can be observed within 1-4 weeks of exposure to ultraviolet light compared to 4 months to 2 years for human or animal studies. These models will be useful for biochemical and mechanistic studies in a large number of fields including dermatology, toxicology, and pharmacology.

• Toxicological Research
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• v.35 no.3
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• pp.249-255
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• 2019

Cadmium is a strong toxic heavy metal which presents in paints and liquid wastes and causes oxidative stress in fish. On the other hand, lead is widely used for different purposes, e.g. lead pipes, it targets vital organs such as liver and kidney causing biochemical alterations. The present study evaluates the effects of 60 days exposure to Cd and Pb either single or combined together in African catfish. Sixty-four fishes were divided into 3 groups and exposed to $CdCl_2$ (7.02 mg/L) or $PbCl_2$ (69.3 mg/L) or a combination of them along with control group. Activities of acid phosphatase (ACP), lactate dehydrogenase (LDH) and glucose-6-phosphate dehydrogenase (G-6-PDH) were estimated. Moreover, gill, liver and kidney were assayed for activities of superoxide dismutase (SOD), catalase (CAT) and levels of glutathione (GSH) and malondialdehyde (MDA). Individual exposure showed that both Cd and Pb significantly decreased LDH activity and SOD activity in the kidney. Pb significantly increased G-6-PDH activity and decreased GSH level in the gill. CAT activity in liver and kidney elevated significantly on Cd exposure while lead caused a significant depletion in the liver and significant elevation in the kidney. Both Cd and Pb significantly increased MDA levels in liver and kidney while Pb increased its level in gills. The combined exposure resulted in normalization of LDH, G-6-PDH activity, and CAT activity in liver and kidney as well as GSH level in both tissues and MDA in gill and kidney. The combination increased SOD activity and MDA level in liver and decreased SOD activity in kidney and GSH level in gills. In conclusion, the antioxidant system of African catfish was adversely affected by prolonged exposure to Cd and Pb. The combined exposure caused less damage than individual exposure and returned most parameters to those of controls.

• Corrosion Science and Technology
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• v.17 no.5
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• pp.231-241
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• 2018

Atmospheric corrosion is generally an electrochemical degradation process of metal. It can be caused by various corrosion factors of atmospheric component, weather, and air pollutants. Moisture, particles of sea salts, and sulfur dioxide are major factors in atmospheric corrosion. Galvanizing coating is one of the most efficient ways to protect iron from corrosion by zinc plating on the surface of the iron. Galvanized steels are being widely used in automobiles, building structures, roofing, and other industrial structures due to their high corrosion resistance compared to bare iron. Atmospheric corrosion of galvanized steel has shown complex corrosion behavior depending on coating process, coating thickness, atmospheric environment, and air pollutants. In addition, different types and kinds of corrosion products can be produced depending on the environment. Lifespan of galvanized steels is also affected by the environment. Therefore, the objective of this study was to determine the corrosion behavior of galvanized steel under atmospheric corrosion at six locations in Korea. When the exposure time was increased, content of zinc from GA surface decreased while contents of iron and oxygen tended to increase. On the other hand, content of iron was constant even after 36 months of exposure of GI.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.530-535
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• 2001

Variations of temperature field in a Hele-Shaw convection cell (HSC) were measured using a holographic interferometry with varying Rayleigh number. Experimental results show a steady flow pattern at low Rayleigh numbers and a time-dependent periodic flow at high Rayleigh numbers. Especially, the period of oscillation at $Ra = 6.35{\times}10^6$ was 62 seconds. Two different measurement methods of holographic interferometry, double-exposure method and real-time method, were employed to measure the temperature field variations of HSC convective flow. In the double-exposure method, unwanted waves can be eliminated and reconstruction images are clear, but transient flow structure cannot be observed clearly. On the other hand, transient flow can be observed and reconstructed well using the real-time method. However, the fringe patterns reconstructed by the real-time method contain more noise, compared with the double-exposure method. The two holographic interferometer techniques employed complementary in this study were proved to be useful for analyzing the temperature field variations of unsteady thermal fluid flows.