• 한국식품위생안전성학회지
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• 제14권4호
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• pp.319-326
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• 1999

최근 국내에서는 Escherichia coli O157:H7, Listeria monocytogenes등의 미생물에 대한 건강위해성이 강조되면서 미생물 위해성평가에 대한 필요성이 제기되고 있고, U.S.FPA, U.S.DA, FAO/WHO를 비롯한 국제기구 및 외국 유관기관들에서도 미생물 위해성평가 방법을 식품관리에 활용하고자 방법론 연구에 주력하고 있다. 미생물 위험성은 화학물질과 달리 인체건강에 대한 영향이 즉각적이고, 심각하게 나타나 정량적인 위해성평가가 용이하지 않고 유해화학물질과는 다른 평가방법이 요구된다. 식품중 미생물의 위해성평가는 크게 4단계로 구분되는데, 미생물관련질환 추세파악 및 미생물 관련질병에 관한 역학조사 등을 활용하는 위험성확인 단계와 실제 식품원료, 식품가공, 수송, 포장단계 중 식품의 물리적, 화학적 조건에 따른 미생물 변화를 고려하여 식품중 미생물에 대한 노출을 정량화하는 노출평가 단계, 미생물의 용량에 따른 질병발생에 근거하여 용량-반응관계를 규명하는 용량-반응평가 단계, 규명된 모델을 활용하여 모든 평가결과를 통합함으로 위해 도치 예측과 불확실성 분석 등을 수행하는 위해도결정단계로 구성되어 있다. 미생물 용량-반응평가는 크게 비역치(Nonthreshold)와 역치(Threshold) 평가 방법론으로 구분되는데, 비역치 평가방법론은 단일 병원균이 감염을 일으킬 수 있다는 것과 감염을 일으킬 수 있는 확률이 독립적이라는 가정을 전제로 하고, 역치평가방법론은 미생물이 감염을 일으키기 위해서 각기 개별 역치가 존재하는데 어느 정도의 미생물수가 모여 서로 작용해야 독성유발물질을 만들어 낸다는 가정을 전제로 한다. 현재 받아들여지고 있는 비역치 모델로는 Exponential, Beta-poisson, Gompertz, Gamma-weibull 모델 등이 있으며, 역치모델로는 Log-normal, Log-logistic모델 등이 있다. 본 연구에서는 인체 volunteer자료를 활용하여 용량-반응자료를 입력하고 용량-반응자료를 토대로 적합한 수학적 모델을 찾아내어, 선별한 모델의 적합도 검정을 실시하는 방법론 연구를 실시하였으며, 노출평가 자료와 용량-반응평가 결과를 연계하여 위해도를 결정하는 과정에 대해 연구하였다 이 밖에도 모델(Food MicroModel)을 이용하여 식품의 염도, 수분활성도, 온도, pH등의 조건에 따른 미생물의 성장률, 사멸률 등 변화를 예측할 수 있는 방법론 연구를 통해 식품의 최적 보관 조건등을 찾아내는 방법을 습득하였다. 미생물 위해성평가는 외국에서도 아직 초기 연구단계에 있으며 현재로서 사후조사자료인 역학자료보다 건강한 성인남자를 대상으로 한 volunteer 자료를 우선적으로 활용하고 있으나 노약자나 민감그룹에 대한 실험은 현실적으로 불가능하여 동물실험을 이용한 평가방법을 연구중에 있다. 추후 연구방향으로는 국내 volunteer들을 대상으로 한 미생물별 용량-반응결과를 토대로 population sensitivity를 비교할 수 있는 기초자료를 확보함으로써 미생물에 대한 인구집단의 반응 민감성 차이를 비교하고 시료채취 후 즉각적인 실험실적 분석이 가능토록하여 정확한 인체노출평가를 수행함으로써 미생물 위해성평가방법론을 식품미생물관리에 적용하는 것이다.

• 대한방사선기술학회지:방사선기술과학
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• 제41권4호
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• pp.339-344
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• 2018

Humans received an exposure dose of 2.4 mSv of natural radiation per year, of which the contribution of spacecraft accounts for about 75%. The crew of the aircraft has increased radiation exposure doses based on cosmic radiation safety management regulations There is no reference to air passengers. Therefore, in this study, we measured the radiation exposure dose received in the sky at high altitude during flight, and tried to compare the radiation exposure dose received by ordinary people during flight. We selected 20 sample specimens, including major tourist spots and the capital by continent with direct flights from Incheon International Airport. Using the CARI-6/6M model and the NAIRAS model, which are cosmic radiation prediction models provided at the National Radio Research Institute, we measured the cosmic radiation exposure dose by the selected flight and departure/arrival place. In the case of exposure dose, Beijing was the lowest at $2.87{\mu}Sv$ (NAIRAS) and $2.05{\mu}Sv$ (CARI - 6/6M), New York had the highest at $146.45{\mu}Sv$ (NAIRAS) and $79.42{\mu}Sv$ (CARI - 6/6M). We found that the route using Arctic routes at the same time and distance will receive more exposure dose than other paths. While the dose of cosmic radiation to be received during flight does not have a decisive influence on the human body, because of the greater risk of stochastic effects in the case of frequent flights and in children with high radiation sensitivity Institutional regulation should be prepared for this.

• Restorative Dentistry and Endodontics
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• 제43권4호
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• pp.36.1-36.12
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• 2018

Objectives: Direct pulp capping is a treatment for mechanically exposed pulp in which a biocompatible capping material is used to preserve pulpal vitality. Biocompatibility tests in animal studies have used a variety of experimental protocols, particularly with regard to the exposure site. In this study, pulp exposure on the occlusal and mesial surfaces of molar teeth was investigated in a rat model. Materials and Methods: A total of 58 maxillary first molars of Wistar rats were used. Forty molars were mechanically exposed and randomly assigned according to 3 factors: 1) the exposure site (occlusal or mesial), 2) the pulp-capping material (ProRoot White MTA or Bio-MA), and 3) 2 follow-up periods (1 day or 7 days) (n = 5 each). The pulp of 6 intact molars served as negative controls. The pulp of 12 molars was exposed without a capping material (n = 3 per exposure site for each period) and served as positive controls. Inflammatory cell infiltration and reparative dentin formation were histologically evaluated at 1 and 7 days using grading scores. Results: At 1 day, localized mild inflammation was detected in most teeth in all experimental groups. At 7 days, continuous/discontinuous calcified bridges were formed at exposure sites with no or few inflammatory cells. No significant differences in pulpal response according to the exposure site or calcium-silicate cement were observed. Conclusions: The location of the exposure site had no effect on rat pulpal healing. However, mesial exposures could be performed easily, with more consistent results. The pulpal responses were not significantly different between the 2 capping materials.

• 한국환경보건학회지
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• 제45권1호
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• pp.30-41
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• 2019

Objectives: The effects of particulate matter and ozone on health are being reported in a number of studies. These effects are likely to be stronger on the elderly population, but studies in this regard are scarce. The purpose of this study was to examine the effects of particulate matter ${\leq}2.5{\mu}m$ and ozone on the acute health status of the elderly population. Methods: In order to analyze the health status of the elderly population, the NHIS-Senior Cohort data was used. In this study of people 60 years or older in Seoul, the number of outpatient visits and ER visits between 2002 and 2013 were calculated. Each disorder and the lag effect were analyzed separately. Particulate matter and ozone were analyzed using both the single exposure model and the adjusted multi-exposure model. Results: In the single exposure analysis with PM2.5 as the exposure variable, with each increase of $10{\mu}g/m^3$, the number of outpatient visits increased by 1.0081 times, vascular disease 1.0065 times, chronic pulmonary disease 1.0086 times, and diabetes 1.0055 times. In the multi-exposure model adjusting for ozone, the number of outpatient visits increased by 1.0066 times. There was a one-day lag effect and 1.0066 times increase between PM2.5 and ER visits in the multi-exposure model and 1.0057 times when adjusted for ozone (p value <0.10). There was a one-day lag effect in all multi-exposure models with ozone as the main variable, and when the particulate matter was adjusted, there was a one-day delay and 1.0143 times increase in ER visits. Conclusions: In our study, an increase in the number of outpatient and ER visits in the elderly population in accordance with the increase in PM2.5 and ozone was found. The association found in our study could also produce a socioeconomic burden. Future studies need to be performed in regards to younger populations and other air pollutants.

• Journal of Radiation Protection and Research
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• 제27권2호
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• pp.121-126
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• 2002

본 연구는 지하수로부터 방출되어 가옥의 실내에 존재하는 라돈에 의한 체내축적량을 현실적으로 평가하는 방법을 보여준다. 먼저 지하수로부터 실내공기로 전달되는 과정을 모의하기 위해 2_구역모델을 개발하였다. 이 모델은 실내에서 발생하는 생활활동, 즉, 목욕, 세수, 세탁, 변기에서의 물사용에 의해 실내로 휘발, 이동하는 시간에 따를 라돈농도분포를 계산한다. 다음, 이 모델의 불확실성이 존재하는 입력인자들에 대해 불확실성분석을 수행하여 최종 실내라돈 농도분포를 결정하였다. 그리고 이러한 실내 라돈을 호흡하여 체내에 축적되는 양을 보다 정량적으로 모의하기 위해 PBPK 모델을 개발하였다. 불확실성이 포함된 라돈농도분포와 정량적인 체내축적모의를 위한 PBPK 모델의 결합으로 보다 현실적인 라돈의 체내축적량을 분석할 수 있다. 이러한 연구의 결과는 지하수로부터 발생하는 라돈에 의한 인체위해평가시 도움을 주리라고 판단된다.

• 한국농공학회논문집
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• 제50권4호
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• pp.17-24
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• 2008

Exposure risk assessment of pesticide molinate using the RICEWQ model in a rice paddy plot was performed to observe the effects of various water and pesticide management scenarios. Several scenarios were developed to represent the specific water and pesticide management practices of rice cultivation in Korea. The results of the scenario analysis using the RICEWQ model simulation from the previous studies were analysed. The molinate risk for aquatic organisms is evaluated by the ratio of the predicted environmental concentration(PEC) and the predicted no-effect concentration(PNEC). The results showed that the no-effect periods for aquatic organisms for the deep, shallow and very shallow irrigation conditions were 33.3, 28.9 and 25.6 DATs for the lable rate application and 36.4, 33.7 and 30.8 DATs for the double lable rate application, respectively. The higher application rate showed greater exposure risk to the aquatic organisms. Based on this study, the withholding period of molinate practiced in Korea, that is 3 to 4 DATs, must be much longer. The results of this study can be used for the non-point source pollution control and environmental policy making regarding pesticides.

• 한국인터넷방송통신학회논문지
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• 제22권4호
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• pp.1-8
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• 2022

본 연구는 인터넷 노출이 플라스틱 소비 행동에 미치는 영향을 살피고, 그 관계에서 사회적 규범의 매개효과를 밝히고자 했다. 연구문제 및 연구모형의 검증을 위해 대학생 220명을 대상으로 설문조사를 실시했다. 수집된 데이터는 SPSS 26.0과 PROCESS macro 4.1(model 4)로 분석했다. 연구 결과, 인터넷 노출은 플라스틱 소비에 관한 묘사적 규범을 매개하여 플라스틱 소비 의도에 정적인 영향을 미치는 것으로 나타났다. 또한 플라스틱 소비에 관한 묘사적 규범과 명령적 규범은 플라스틱 소비 의도에 정적인 영향을 미쳤다. 이러한 결과는 인터넷 노출과 사회적 규범이 플라스틱 소비 행동을 촉진하거나 억제할 수 있는 중요한 요인임을 시사한다. 이 결과를 토대로 본 연구의 이론적 의의와 실무적 함의를 제시했다.

• Journal of Photoscience
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• 제9권2호
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• pp.500-502
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• 2002

In vitro and in vivo studies have reported the induction of matrix metaloproteinase (MMP)-1 in the fibroblasts by ultraviolet (UV) A irradiation. We constructed the skin equivalent model using HaCaT cells as keratinocytes and human neonatal dennal fibroblasts as fibroblasts in the present study. The induction of MMP-l in the fibroblasts was confirmed immunohistochemically 6 hours after UVA irradiation using this model. This model was simply composed of human keratinocytes and fibroblasts. To our knowledge, there have been a few papers concerning the skin equivalent model in the field of photobiology. The effect of UVA exposure to fibroblasts through keratinocytes was examined using this model. The cross-talk can be examined between keratinocytes and fibroblasts. This model can be a useful tool in the field of photobiology.

• 한국소음진동공학회논문집
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• 제25권4호
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• pp.284-290
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• 2015

Road traffic noise is closely related with urban forms and urban components, such as population, building, traffic and land-use, etc. Hence, it is possible to minimize the noise exposure problem depending on how to plan new town or urban planning alteration. This paper provides ways to apply for urban planning in consideration of noise exposure through road traffic noise estimation for alteration of small-scale urban form. Spatial autoregressive model from the former study is used as statistical model for noise simulation. The simulation results by the spatial statistical model are compared with those by the engineering program-based modeling for 5 scenarios of small-scale urban form alteration. The error from the limitation of containing informations inside the grid cell and the difficulties of reflecting acoustic phenomena exists. Nevertheless, in the stage of preliminary design, the use of the statistical models that have been estimated well could be useful in time and economically.

• Structural Engineering and Mechanics
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• 제81권2호
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• pp.163-178
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• 2022

This paper aimed to study the local bond-slip behavior between ultra-high-performance concrete (UHPC) and a reinforcing bar after exposure to high temperatures. A series of pull-out tests were carried out on cubic specimens of size 150×150×150 mm with deformed steel bar embedded for a fixed length of three times the diameter of the tested deformed bar. The experimental results of the bond stress-slip relationship were compared with the Euro-International Concrete Committee (CEB-Comite Euro-International du Beton)-International Federation for Prestressing (FIP-Federation Internationale de la Precontrainte) Model Code and with prediction models found in the literature. In addition, based on the test results, an empirical model of the bond stress-slip relationship was proposed. The evaluation and comparison results showed that the modified CEB-FIP Model code 2010 proposed by Aslani and Samali for the local bond stress-slip relationship for UHPC after exposure to high temperatures was more conservative. In contrast, for both room temperature and after exposure to high temperatures, the modified CEB-FIP Model Code 2010 local bond stress-slip model for UHPC proposed in this study was able to predict the test results with reasonable accuracy.