• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.25-39
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• 2003

Risk and exposure assessment for subsurface environment is very important for both aspects of health and environmental protection as well as making decision of remedial goal for engineering activities. Exposure due to hazardous chemicals in the subsurface environment is essential to assess risk lev121 to individual person, especially from soil and groundwater environmental media. In this paper, the status of soil and groundwater contamination is presented to discuss on the problem for environmental risk assessment. The methodologies of fate and exposure models are also discussed by conducting the case studies of exposure assessment for heavy metals, organic compounds, and dioxin compounds. In addition, the structure of exposure models and available data for model calculation are examined to make clear more realistic exposure scenarios and the application to the practical environmental issues. Three kinds of advanced remediation techniques for soil and groundwater contamination are described in this paper, The most practical method for VOCs is the bio-remediation technique in which biological process due to consortium of microorganisms can be applied. For more effective remediation of soil contaminated by heavy metals we have adopted the soil flushing technique and clean-up system using electro-kinetic method. We have also developed the advanced techniques of geo-melting method for soil contaminated by DXNs and PCB compounds. These techniques are planed to introduce and to apply for a lot of contaminated sites in Japan.

• 정보저장시스템학회:학술대회논문집
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• 정보저장시스템학회 2005년도 추계학술대회 논문집
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• pp.139-144
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• 2005

Because of the photorefractive recording dynamics, each newly recorded hologram partially erases all previously stored image. Thus achieving the desired diffraction efficiency profile for the entire sequence after all images have been recorded requires exposure time schedule. The often cited classical exposure-schedule model predicts a rising-exponential build-up and an exponential decay in An with an exposure time. However because we cannot directly measure the An, it's difficult to establish the relation of both. In this paper, we deduce the relation of diffraction efficiency and exposure time from experiment data and suggest an algorithm to make time schedule profile in angle/fractal multiplexing of holographic data storage. After that, we present simulated result with equal hologram diffraction efficiency for a sequence of 250 holograms recorded by angle/fractal multiplexing.

• 대한지역사회영양학회지
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• 제28권3호
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• pp.192-205
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• 2023

Objectives: Previous studies have evaluated the association between mercury exposure and obesity but have yielded mixed conclusions. The aim of this study was to systematically review and summarize scientific evidence regarding the association between mercury exposure and obesity in the human population. Methods: We conducted a systematic search of PubMed, Web of Science, Scopus, and Science Direct for articles related to mercury exposure and obesity. Meta-analyses of the highest and lowest categories of mercury levels were evaluated using a random effects model. Begg's test was used to detect publication bias. Results: A total of 9 articles were included. The pooled random effects odds ratio (OR) for mercury exposure and obesity of all 9 studies was 1.66 (95% confidence interval [CI]: 1.16-2.38). This positive association was evident in adults (OR: 1.61, 95% CI: 1.02-2.54) and among studies with Asian populations (OR: 2.00, 95% CI: 1.53-2.59), but not among those with North America/African populations (OR: 0.90, 95% CI: 0.50-1.65). Conclusions: The present meta-analysis identified a positive association between mercury exposure and obesity. These findings suggest that toxic environmental metals such as mercury may be an important risk factor for obesity along with dietary habits and lifestyles.

• 문화기술의 융합
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• 제7권2호
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• pp.35-48
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• 2021

본 연구는 대학생의 개인특성과 인터넷 사용특성, 음란물 노출 및 반사회적 성의식과의 관계를 규명하기 위해 모형을 구축하고 이들 요인간의 관계를 규명하고자 시도되었다. 연구대상은 B시 소재 만18세 이상의 대학생 360명을 대상으로 하였으며, 수집된 자료는 IBM SPSS 21.0/AMOS 22.0 프로그램으로 분석하였다. 수정모형의 적합도 지수는 수용기준을 충족하였다(𝛘²/df=2.786, GFI=.95, AGFI=.92, SRMR=.06, RMSEA=.07, NFI=.89, CFI=.93, TLI=.90). 경로분석 결과, 대학생의 반사회적 성의식에 직접적인 영향을 미치는 변수는 개인특성과 음란물 노출이었으며, 간접적인 영향을 미치는 변수는 인터넷 사용특성이었다. 반사회적 성의식에 직접적인 효과가 가장 큰 것은 음란물 노출이었으며, 음란물 노출은 개인특성과 인터넷 사용특성의 직접적인 영향을 받는 것을 확인하였다. 따라서 대학생의 반사회적 성의식 감소를 위해서는 음란물 노출에 직접적인 영향을 미치는 개인특성 및 인터넷 사용특성을 조절하는 방안이 마련되어야 할 것이다.

• Nuclear Engineering and Technology
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• 제52권8호
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• pp.1826-1833
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• 2020

Administration of stable iodine has been considered a best measure to protect the thyroid from internal irradiation by radioiodine intake, and its efficacy on thyroid protection has been quantitatively evaluated in several simulation studies on the basis of simple iodine biokinetic models (i.e., three-compartment model). However, the new iodine biokinetic model adopted by the International Commission on Radiological Protection interprets and expresses the thyroid blocking phenomenon differently. Therefore, in this study, the new model was analyzed in terms of thyroid blocking and implemented to reassess the protective effects and to produce dosimetric data. The biokinetic model calculation was performed using computation modules developed by authors, and the results were compared with those of experimental data and prior simulation studies. The new model predicted protective effects that were generally consistent with those of experimental data, except for those in the range of stable iodine administration -72 h before radioiodine exposure. Additionally, the dosimetric data calculated in this study demonstrates a critical limitation of the three-compartment model in predicting bioassay functions, and indicated that dose assessment 1 d after exposure would result in a similar dose estimate irrespective of the administration time of stable iodine.

• International Journal of Concrete Structures and Materials
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• 제11권2호
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• pp.199-213
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• 2017

Chloride penetration is among the main causes of corrosion initiation in reinforced concrete (RC) structures producing premature degradations. Weather and exposure conditions directly affect chloride ingress mechanisms and therefore the operational service life and safety of RC structures. Consequently, comprehensive chloride ingress models are useful tools to estimate corrosion initiation risks and minimize maintenance costs for RC structures placed under chloride-contaminated environments. This paper first presents a coupled thermo-hydro-chemical model for predicting chloride penetration into concrete that accounts for realistic weather conditions. This complete numerical model takes into account multiple factors affecting chloride ingress such as diffusion, convection, chloride binding, ionic interaction, and concrete aging. Since the complete model could be computationally expensive for long-term assessment, this study also proposes model simplifications in order to reduce the computational cost. Long-term chloride assessments of complete and reduced models are compared for three locations in France (Brest, Strasbourg and Nice) characterized by different weather and exposure conditions (tidal zone, de-icing salts and salt spray). The comparative study indicates that the reduced model is computationally efficient and accurate for long-term chloride ingress modeling in comparison to the complete one. Given that long-term assessment requires larger climate databases, this research also studies how climate models may affect chloride ingress assessment. The results indicate that the selection of climate models as well as the considered training periods introduce significant errors for mid- and long- term chloride ingress assessment.

• Journal of Preventive Medicine and Public Health
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• 제33권3호
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• pp.343-348
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• 2000

Objectives : This study was conducted to integrate the results of studies assessing the association between chronic noise exposure and blood pressure. Methods : Using a MEDLINE search with noise exposure, blood pressure and hypertension as key words, we retrieved articles from the literature that were published from 1980 to December 1999. The criteria for quality evaluation were as follows: 1) the study subjects must have been workers employed at a high noise level area 2) The paper should use average and cumulative noise exposure as method for exposure evaluation. 3) Blood pressure in each article should be reported in a continuous scale Among the 77 retrieved articles, six studies were selected for quantitative meta-analysis. Before the integration of the regression coefficients for the association between blood pressure and noise level, homogeneity tests were conducted. Results : All studies were a cross-sectional design and the study subjects were industrial workers. Five papers used a time-weighted average for noise exposure and only one paper calculated the cumulative noise exposure level. The measurement of blood pressure in the majority of studios were accomplished in a resting stale, and used an average of two or more readings. The homogeneity of studies was rejected in a fixed effect model, so we used the results in a random effect model. The results of the quantitative meta-analysis, the weighted regression coefficient of noise associated with systolic blood pressure and diastolic blood pressure were 0.05 (95% confidence interval [CI]: -0.03, 0.13) and 0.06 (95% CI: -0.01, 0.13), respectively. Conclusions : Our results suggested that chronic exposure to industrial noise does not cause elevated blood pressure.

• Journal of Radiation Protection and Research
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• 제19권3호
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• pp.209-221
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• 1994

원자력발전소의 중대 사고시 대기로 방출된 방사성물질에 의해 피폭자가 사고후 일생동안 받게 될 전신 피폭선량과 핵종의 상대적 중요도를 방출점으로부터 거리에 따라 각 피폭경로에 대해 평가하였다. 방사능운과 지표에 침적된 방사성물질에 의한 외부피폭, 호흡과 오염된 음식물섭취에 의한 내부피폭이 피폭경로로 고려되었다. 오염된 음식물섭취에 의한 영향은 우리나라 환경을 고려하여 개발된 동적 삽식경로모델 KORFOOD을 사용하여 침적시점과 침적후 시간에 따른 음식물내 방사성물질의 농도 변화를 고려하였다. 방출점으로부터 80km까지 피폭선량을 평가한 결과, 오염된 음식물섭취에 의한 영향이 가장 높았다. 핵종별 기여도는 방사능운에 의한 외부피폭과 호흡에 의한 내부피폭의 경우 I, 침적된 방사성물질에 의한 외부피폭의 경우 Cs에 의한 영향이 가장 높았다. 오염된 음식물섭취에 의한 내부피폭의 경우 Cs은 여름철 침적, Sr은 겨울철 침적에 보다 중요한 영향을 미쳤다.

• 한국환경보건학회지
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• 제37권5호
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• pp.358-368
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• 2011

Objectives: In order to evaluate the association between occupational exposure to chloroethylene (TCE) and risk of non-Hodgkin lymphoma (NHL), we conducted a meta-analysis of retrospective cohort studies and casecontrol studies and attempted to summarize the evidence of the association from molecular-epidemiological studies and experiments with human cells. Methods: In the meta-analysis, we restricted the analysis to those studies with data for chlorinated solvents, degreasers, or TCE. Studies involving dry cleaners or launderers were excluded from the analysis because use of TCE as a dry cleaning fluid has been rare since the 1960s. The data were combined using a random-effects model to estimate the summary risks (OR and RR) and 95% confidence intervals (CIs). Molecular evidence of the effect of TCE on human immune system were also reviewed and summarized. Results: Occupational exposure to TCE was strongly associated with NHL among cohort studies (number of studies=13, summary RR=1.33, 95% CI=1.04-1.70) whereas the association was not statistically significant among case-control studies (number of studies=15, summary OR=1.10, 0.98-1.23). When exposure level was considered, it became statistically significant for the highest exposure level (number of studies=5, summary OR=1.70, 1.25-2.32). Molecular evidences showed that TCE exposure in human or cultured human cells may cause a significant decrease immune cell subsets and changes in hormone levels related to immune response. Conclusions: Our results from meta-analysis and additional molecular evidence suggest that occupational exposure to TCE may cause NHL. However, unmeasured potential confounding and unclear dose-response relationships warrant further study on the role of TCE exposure in NHL carcinogenesis.

• Archives of Pharmacal Research
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• 제29권12호
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• pp.1158-1163
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• 2006

More than 95% of lead, a environmental heavy metal, entering into blood accumulates in erythrocytes suggesting erythrocytes as an important target of lead toxicity. Recent studies reported that erythrocytes could contribute to blood coagulation via phosphatidylserine (PS) exposure in erythrocytes. However, in vivo effects of chronic lead exposure especially by drink-ing water on procoagulant activity of erythrocytes have not been studied yet. In the present study, we investigated the effects of chronic exposure of lead by drinking water on erythrocytes in rats. Groups of 40 male rats were provided with drinking water containing various concentrations of lead for 4 weeks and complete blood cell count, procoagulant activities of erythrocytes and platelets were evaluated with basic inspections on body weight and food/water consumption. The administration of lead containing drinking water increased the blood lead level (BLL) in a dose-dependent manner up to $22.39{\pm}2.26\;{\mu}g/dL$. Water consumption was significantly decreased while food consumption or body weight gain was not affected. In contrast to the previous findings with acute lead exposure, chronic lead exposure failed to increase PS exposure in erythrocytes with statistical significance although some trends of enhancement were observed. It implies that a certain adaptation might have happened in body during repeated exposure to lead, resulting in attenuation of PS exposure. With this study, we believe that a valuable information was provided for the study on the toxicological significance and the risk assessment of lead contaminated drinking water.