• Journal of electromagnetic engineering and science
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• 제15권3호
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• pp.142-150
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• 2015

Several reports supported that continuous exposure to 60 Hz magnetic field (MF) induces testicular germ cell apoptosis in vivo. We recently evaluated duration- and dose-dependent effects of continuous exposure to a 60 Hz MF on the testes in mice. BALB/c male mice were exposed to a 60 Hz MF at $100{\mu}T$ for 24 hours a day for 2, 4, 6, or 8 weeks, and at 2, 20 or $200{\mu}T$ for 24 hours a day for 8 weeks. To induce the apoptosis of testicular germ cell in mice, the minimum dose is $20{\mu}T$ at continuous exposure to a 60 Hz MF for 8 weeks, and the minimum duration is 6 weeks at continuous exposure of $100{\mu}T$. Continuous exposure to a 60 Hz MF might affect duration- and dose-dependent biological processes including apoptotic cell death and spermatogenesis in the male reproductive system of mice. The safety guideline of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) indicates that the permissible maximum magnetic flux density for general public exposure is $200{\mu}T$ at 60 Hz EMF (ICNIRP Guidelines, 2010). In the present study, we aimed to examine the expression of pro- and anti-apoptotic genes regulated by the continuous exposure to 60 Hz at $200{\mu}T$ in Sprague-Dawley rats for 20 weeks. The continuous exposure to 60 Hz at $200{\mu}T$ does not affect the body and testicular weight in rats. However, exposure to 60 Hz MF significantly affects testicular germ cell apoptosis and sperm count. Further, the apoptosis-related gene was scrutinized after exposure to 60 Hz at $200{\mu}T$ for 20 weeks. We found that the message level of endonuclease G (EndoG) was greatly increased following the exposure to 60 Hz at $200{\mu}T$ compared with sham control. These data suggested that 60 Hz magnetic field induced testicular germ cell apoptosis through mitochondrial protein Endo G.

• 한국산업보건학회지
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• 제25권2호
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• pp.134-145
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• 2015

Objectives: An objective of this study was to perform a risk assessment and social cost-benefit analysis for revising permissible exposure limits for seven substances: Nickel(Insoluble inorganic compounds), benzene, carbon disulfide, formaldehyde, cadmium(as compounds), trichloroethylene, touluene-2,4-diisocyanate. Materials and Methods: The research methods were divided into risk and hazard assessment and cost-benefit analysis. The risk and hazard assessment for the seven substances consists of four steps: An overview of GHS MSDS(1st), review of document of ACGIH's TLVs (2nd), comparison between international occupational exposure limits and domestic permissible exposure limits(3rd), and analysis of excess workplace and excess rate for occupational exposure limits based on previous work environment measurement data(4th). Total cost was estimated using cost of local exhaust ventilation, number of excess workplace and penalties for exceeding a permissible exposure limit. On the other hand, total benefit was calculated using the reduction rate of occupational disease, number of workplaces treating each substance and industrial accident compensation. Finally, the net benefit was calculated by subtracting total cost from total benefit. Results: All the substances investigated in this study were classified by CMR(Carcinogens, Mutagens or Reproductive toxicants) and their international occupational exposure limits were stricter than the domestic permissible exposure limits. As a result of excess rate analysis, trichloroethylene was the highest at 11%, whereas nickel was the lowest at 0.5%. The excess rates of all substances except for trichloroethylene were observed at less than 10%. Among the seven substances, the total cost was highest for trichloroethylene and lowest for carbon disulfide. The benefits for the seven substances were higher than costs estimated based on strengthening current permissible exposure limits. Thus, revising the permissible exposure limits of the seven substances was determined to be acceptable from a social perspective. Conclusions: The final revised permissible exposure limits suggested for the seven substances are as follows: $0.2mg/m^3$ for nickel, 0.5 ppm(TWA) and 2.5 ppm(STEL) for benzene, 1 ppm(TWA) for carbon disulfide, $0.01mg/m^3$(TWA) for cadmium, 10 ppm(TWA) and 25 ppm(STEL) for trichloroethylene, 0.3 ppm(TWA) for formaldehyde, and 0.005 ppm(TWA) and 0.02 ppm(STEL) for toluene diisocynate(isomers).

• 농약과학회지
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• 제15권4호
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• pp.507-528
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• 2011

포장에서 농약 살포액의 조제, 살포 등의 작업을 수행하는 농작업자는 피부노출, 호흡노출경로를 통해 농약에 노출되며, 이러한 상황에서의 농약 노출에 대한 합리적인 위해성 평가를 위해서는 해당 영농상황에서 노출량을 정량적으로 측정해야 한다. 농약 노출 측정방법으로 patch, 장갑, 양말, 마스크를 이용하는 방법과 호흡 노출은 주로 고체흡착제와 공기흡입펌프가 연결된 personal air monitor를 사용하는 것이 좋을 것으로 판단된다. 이 농작업자의 정량적 피부 노출 측정법으로 유효할 것으로 판단된다. 노출 재료에 침착/부착된 농약량이나 고체흡착제에 포집된 농약량을 신체 전체에 대한 농약 노출량으로 외삽하기 위한 EPA 자료를 대체할 수 있도록 한국 사람의 표준 신체표면적 및 호흡률을 제안하였다. 중요한 노출 인자인 피부노출의 의복 침투율과 피부 침투율, 그리고 호흡노출의 침투율을 UK-POEM과 관련된 연구결과를 참고하여 다양하게 제안하였다. 노출 평가를 위한 살포 시간은 노출 측정 재료에 침착된 농약이 분석이 될 만큼 충분한 농약이 포집될 수 있도록 살포시간이 충분해야 하는데, 국내의 SS기나 동력분무기의 경우는 1반복 당 모두 약 20~40분에 살포(약 0.1~0.2 ha)로 해서 3반복 측정 결과를 4시간으로 환산할 것을 제안하였다.

• 한국보건간호학회지
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• 제16권1호
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• pp.45-63
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• 2002

The purpose of this study is to understand the current status of high school students' exposure to pornographic materials as well as to provide basic data to develop sex education programs. This study was conducted through a self-administered questionnaire survey of 774 students of six high schools in Seoul, three boys' and three girls' respectively, from August 22 to August 25, 2000. This study shows that high school students' exposure to pornographic materials such as CD-ROMs, internet, video tapes and adult movies has become very serious. The results of this study are as follows. 1. Among the students surveyed, $23.5\%$ of them currently has opposite-sex friends, while $42.2\%$ used to have and $34.2\%$ has never had opposite-sex friends. 2. $55.3\%$ of the students pick up their sexual knowledge from their friends, followed by mass media $(47.5\%),\;school (21.1\%),\;adult\; magazines (17.1\%)\;, internet (14.1\%)$, pornography visual $materials (11.5\%),\; sexual\; books (3.6\%)$ and pornography printed $materials (2.4\%).$ 3. Regarding the frequency of sexual education taken in school, $54.2\%$ of the students answered 'often', while $37.6\%$ answered 'almost none', 'several times' $(4.4\%)$, 'never' $(2.9\%)$ and 'frequently' $(0.9\%)$, respectively. Regarding sexual education at home, $42.2\%$ answered 'almost none', followed by 'never' $(36.3\%)$, 'often' $(16.3\%)$, 'several times' $(3.3\%)$ and 'frequently' $(1.8\%)$, respectively. 4. $68.2\%$ of the students have been exposed to adult movies, followed by pornography videos $(60.1\%)$, internet chatting $(50.2\%)$ and pornography computer diskettes $(38.0\%)$. 5. The degree of exposure to pornographic materials of boy students is much higher than that of girl students. 6. It appears that there is an interrelation between the kind of schools and the degree of the students' exposure to pornographic materials. 7. The higher the students' grade is. the more they have been exposed to pornographic materials. 8. It shows that there is an interrelation between the students' academic performance and the degree of their exposure to pornographic materials. 9. There is also an interrelation between the amount of students' pocket money and the degree of their exposure to pornographic materials. 10. There is an interrelation between the degree of their adaptation to school life and the degree of their exposure to pornographic materials. 11. It appears that there is an interrelation between their parents' relations with them and the degree of the students' exposure to pornographic materials. 12. There is a significant difference in the degree of their exposure to pornographic materials in accordance with their residential area. 13. There is also a significant difference in the degree of their exposure to pornographic materials in accordance with the average income of their families. 14. There is also a significant difference in the degree of their exposure to pornographic materials in accordance with the mean sexual education at home.

• 한국방사선학회논문지
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• 제13권3호
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• pp.473-479
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• 2019

다양한 촬영 조건의 CT 감쇠 지도가 PET 영상에 영향을 미치는지 알아보기 위하여 다양한 kVp와 mA조건에서 Uniformity phantom 영상의 신호 강도(SI; Signal Intensity)와 표준 섭취율 계수(SUV; Standardized Uptake Value)를 측정하고, CTDI (Computed Tomography Dose Index)를 통해 각 조건에 따른 피폭선량을 측정하였다. 또한 동일한 조건에서 Resolution phantom의 반치폭(FWHM; Full Width at Half Maximum)을 측정하여 CT의 kVp와 mA에 따른 PET 영상의 화질 변화에 대하여 정량적으로 알아보고자 하였다. 연구 결과, CT의 촬영 조건은 PET 영상에는 영향을 주지 않는 것으로 나타났으나, CT의 촬영 조건이 감소하게 되면 방사선 피폭이 감소하게 되지만 영상에 영향을 미치게 되므로 향후 진단이 가능한 CT 화질을 유지하면서 방사선 피폭을 최소화할 수 있는 양전자 방출 단층 촬영(PET/CT; Positron Emission Tomography / Computed Tomography)의 촬영 조건에 대한 연구가 지속적으로 되어야 할 것이다.

• 한국환경보건학회지
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• 제48권2호
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• pp.75-85
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• 2022

Background: Various types of semi-volatile organic compounds (SVOCs) exist in the public's living environment. They occur in different forms in terms of their physical and chemical properties and partition coefficients. As a consequence, indoor exposure to SVOCs occurs via various routes, including inhalation of air and airborne particles, skin contact, and dust intake. Objectives: To propose a method for assessing human exposure to the SVOCs occurring in the air of an indoor environment, the concentrations of SVOCs in house dust and organic films measured in a real residential environment were estimated in terms of gas-phase concentration using the partition coefficient. Assessment of inhalation exposure to SVOCs was performed using this method. Methods: Phthalates were collected from samples of house dust and organic films from 110 households in a real residential environment. To perform an exposures assessment of the phthalates present in organic films, gas-phase concentration was calculated using the partition coefficient. The airborne gas-phase concentrations of phthalates from the house dust and organic films were estimated and exposure assessment was performed based on the assumption of inhalation exposure from air. Results: As a result of the exposure assessment for gas-phase phthalates from house dust and organic films, preschool children showed the highest level of inhalation of phthalates, followed by school children, adults, and adolescents. Conclusions: This study includes the limitation of not considering different SVOCs exposure pathways in the health impact assessment, including those of phthalates in the indoor living environment. However, this study has the significance of performing exposure assessment based on exposure to SVOCs present in indoor air that originated from organic films in the indoor residential environment. Therefore, the results of this study should be useful as basic data for exposure and health risk assessments of SVOCs associated with organic films in the indoor environment.

• 한국환경보건학회지
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• 제48권4호
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• pp.195-205
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• 2022

Background: The biggest concern when using household chemical products is the health risk from inhalation exposure. Objectives: The purpose of this paper was to provide information necessary for estimating inhalation exposure factors in several countries/organizations and to present some examples. Methods: We attempted to use PRISMA-ScR for a systematic review, but no major reports were found. We used the Google search function instead to find 'exposure factor handbook'. As for the results, inhalation exposure factors from South Korea, the United States, Canada, the EU, Australia, Japan, and China were compared. Results: The basic concept and origin of exposure factors was the US Environmental Protection Agency's Exposure Factor Handbook. Its latest version is 2011, but several chapters have been updated in 2017, 2018, and 2019. South Korea's Exposure Factor Handbook was updated in 2019, more recently than those of other countries, and was systematically investigated. In South Korea, the average daily respiratory rate is 14.62 m³/day for adults and 12.73 m³/day for children. It is difficult to compare breathing rate by country because each country divides age groups differently and uses different methods to estimate it. Information on household chemical products, space used, and ventilation rate are in the exposure factor handbook in some countries and not in others. It is not in the handbook in South Korea, but in the notice from the NIER (National Institute of Environmental Research), a sub-regulation of the Chemical Product Safety Act. Conclusions: The exposure factors registered in South Korea's exposure factor handbook have been systematically studied and reflect the most recent data. When using data not in the relevant handbook, data from other countries might be applied, but it should be determined whether the nature and quality of the original data have been managed.

• 생태와환경
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• 제56권4호
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• pp.406-413
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• 2023

어류의 시각적 및 화학적 정보를 토대로 포식자를 인지하는 능력은 개체가 자연에서 생활하는 동안 학습을 통해서 확보된다. 하지만 인공증식된 멸종위기종들의 경우 자연적응력 부족으로 인한 복원효율성 저하가 지속적으로 발생하고 있다. 따라서 본 연구에서는 복원을 위해 인공증식된 멸종위기종 여울마자의 자연적응력 증진을 위해 포식자 인지 능력 증진을 수행하였다. 연구결과 포식자 인지 훈련 기간에 따라 자극원에 대한 반응성이 달라짐을 확인할 수 있었으며, 인공증식된 여울마자는 동종의 알람신호를 통해 위험을 인지하는 능력이 떨어져 있었으며, 이는 포식 위험원 노출을 통한 훈련으로 개선이 가능하였고, 포식자에 노출되었을 때 포식자와 알람신호에 동시에 노출 되었을 경우 훈련 기간이 길어짐에 따라 자극에 대한 반응성이 줄어드는 것을 확인하였다. 알람신호에 대한 반응은 시간이 지날수록 커지는 경향을, 포식자에 대한 반응은 훈련 48시간 후 가장 높은 반응을 보이고 72시간 후 반응성이 떨어지는 경향을, 알람신호와 포식자 동시 노출에 대한 반응은 훈련 이전 가장 높은 반응을 보인 뒤 반응성이 낮아진 채로 유지되는 경향을 보였다. 따라서 방류 전 인공증식 개체의 동종의 알람신호(화학적 자극)에 대한 반응성을 높이기 위한 프로그램이 필요하며, 포식자(시각적 자극)에 대한 반응성도 높게 나타난 48시간가량의 포식 위험원 노출이 적합하다고 판단된다. 본 실험을 통해 인공증식 여울마자의 동족 알람신호 자극에 대한 반응성 부족이 확인되었으며 멸종위기종 방류전 자연성 증진 프로그램의 운용의 필요성이 확인되었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 가을 학술발표회 논문집
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• pp.175-182
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• 1996

This paper deals with the properties of water permeability and porosity of cement mortar substrate coated with siliceous slurry coating under the exposure environment. Conditions of exposure enviornment are four kinds of in constant temperature water and humidity box, in indoor and outdoor exposure. Coated mortar substrate was expected continually increase in water and humidity condition, but was not in dry condition. Watertightness effect of siliceous coating was better in the condition of humidity then the dry condition, and the pore volume was decreased in that condition.

• Nuclear Engineering and Technology
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• 제7권2호
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• pp.159-165
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• 1975

The Nuclear power industry today faces a serious and rapidly emerging problem in reactor maintenance and occupational radiation exposure control. The basic problem is the need for much maintenance on nuclear power plants. The problem is seriously compounded by radiation exposure control requirements. Many studies are underway seeking solutions tut the industry is developing rapidly and new plants will not await the results of such studies. It is essential that attention be given to maintenance and exposure control in all phases of plant design, construction and operation.