• Journal of Korea Water Resources Association
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• v.56 no.7
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• pp.451-460
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• 2023

In this study, the risk of red water and turbid water occurrence was analyzed by classifying it into detachment risk and deposition risk. First, risk factors for red water and turbid water were determined, and hydraulic analysis was conducted considering seasonal water consumption. The applied area was Cheongju City, and the risk analysis was conducted across 13 areas, and the areas with high deposition risk and high detachment risk were selected. The high risk of both detachment and deposition can be judged as an area with a very high probability of causing water quality problems. The areas with the highest deposition risk and detachment risk are the old towns of Nae deok1-dong and Yul1yang-dong, which are the oldest areas in Cheongju City with an age of more than 30 service years of pipe installation. By analyzing the risk of deposition and detachment, it will be possible to strengthen the maintenance function of the water supply network to provide the safe water to citizens and increase their confidence for tap water.

• Asian Journal of Atmospheric Environment
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• v.5 no.4
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• pp.205-215
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• 2011

Ozone ($O_3$) is a main component of photochemical oxidants and a phytotoxic air pollutant. Although the current levels of tropospheric $O_3$ in East Asia could adversely affect productivity of forest tree species, risk assessments of $O_3$ impact were limited. In this paper, we summarize the methodology of risk assessment of $O_3$ on forest tree species based on our two previous studies, risk assessments of $O_3$ impact on the growth of Fagus crenata by Watanabe et al. (2012) and on the annual carbon absorption of three representative conifers, Cryptomeria japonica, Pinus densiflora and Larix kaempferi by Watanabe et al. (2010). $O_3$ sensitivity of each tree species obtained from an experimental study, $O_3$ exposure and atmospheric N deposition based on field monitoring and vegetation survey were integrated by geographic information system method. Based on the results, we conclude that the area with high risk of $O_3$ impact does not necessarily correspond to the area with high $O_3$ exposure. The varieties of tree habitat, tree sensitivity to $O_3$ and annual carbon absorption among the tree species, and N deposition-induced change in the $O_3$ sensitivity of F. crenata are raised as the factors of discordance between areas with high risk and those with high $O_3$ exposure. In the last part of this paper, we discuss the present uncertainty and perspectives of risk assessment for the future studies on the impact of $O_3$ on forest tree species in East Asia.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.5
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• pp.551-560
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• 2003

Particle deposition in human lungs was investigated theoretically by using asymmetric five-lobe lung model. The volumes of each of the five lobes were different, thereby forming an asymmetric lung structure. The tidal volume and flow rate of each lobe were scaled according to lobar volume. The total and regional deposition with various breathing patterns were calculated by means of tracking volume segments and accounting for particle loss during inhalation and exhalation. The deposition fractions were obtained for each airway generation and lung lobe, and dominant deposition mechanisms were investigated for different size particles. Results show that the tidal volume and flow rate have a characteristic influence on particle deposition. The total deposition fraction increases with an increase in tidal volume for all particle sizes. However, flow rate has dichotomous effects: a higher flow rate results in a sharp increase in deposition for large size particles, but decreases deposition for small size particles. Deposition distribution within the lung shifts proximally with higher flow rate whereas deposition peak shifts to the deeper lung region with larger tidal volume. Deposition fraction in each lobe was proportional to its volume. Among the three main deposition mechanisms, diffusion was dominant for particles < 0.5 ${\mu}{\textrm}{m}$ whereas sedimentation and impaction were most influential for larger size particles. Impaction was particularly dominant for particles> 8 ${\mu}{\textrm}{m}$. The results may prove to be useful for estimating deposition dose of inhaled pollutant particles at various breathing conditions.

• Korean Journal of Radiology
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• v.20 no.1
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• pp.134-147
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• 2019

Gadolinium-based contrast agents (GBCAs) are commonly used for enhancement in MR imaging and have long been considered safe when administered at recommended doses. However, since the report that nephrogenic systemic fibrosis is linked to the use of GBCAs in subjects with severe renal diseases, accumulating evidence has suggested that GBCAs are not cleared entirely from our bodies; some GBCAs are deposited in our tissues, including the brain. GBCA deposition in the brain is mostly linked to the specific chelate structure of the GBCA: linear GBCAs were responsible for brain deposition in almost all reported studies. This review aimed to summarize the current knowledge about GBCA brain deposition and discuss its clinical implications.

• Journal of Korean Society for Atmospheric Environment
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• v.12 no.5
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• pp.555-566
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• 1996

In order to assess the long-term airborne concentrations of 6 metals such as Cr, Cd, Pb, Zn, K, and Na and the associated health resk, a great number of PM-10 samples were collected and analyzed in Kyung Hee University-Suwon Campus for three years from 1991 to 1993. The 3-year average concentration of Pb in respirable particulate matters was 142.6 ng/m$^{3}$ while that of Zn was 1,210.5ng/m$^{3}$. The corresponding hazard index from Pb Zn for the ingalation route was estimated to be 9.5.times.10$^{-2}$ and 3.5.times.10$^{-2}$ , respectively. Therefore, it can be said that there was no adverse chronic health effects by airborne Pb and Zn. However, the 2-year average concentration of Cr(6) was estimated to be 1.3ng/m$^{3}$ shile the 3-year average concentration of Cd was 3.1ng/m$^{3}$. The total cancer risk by these two metals for the inhalation route was estimated to be about 7.2.times.10$^{-6}$ . This order-of-magnitude risk estimate suggests that the ingalation risk in the study area from all carcinogenic metals including As and Ni (subsulfide) might exceed the acceptable risk criteria of 10$^{-5}$ -10$^{-6}$ by U.S.EPA.For a better risk assessment in the future, alveolar deposition of PM-10 in the study area were also discussed and an assessment was done.

• Fire Science and Engineering
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• v.22 no.2
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• pp.121-128
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• 2008

Adverse health effects of inhaled smokes are associated with the amount of the particles deposited in human lung. Lung model is needed to simulate smoke deposition because of the hardness of the in vivo deposition experiment. However, it is hard to realize the successively decreasing bifurcations in the model. In this work, an experimental lung model was developed to simulate the smoke deposition in the lung. Instead of bifurcating airways, the lung model was made of packed beds of which size decreased downwards. The experimental results using this model showed good agreements with existing results for real lung in the deposition characteristics. The model could be applied to the studies of health risk assessment of the inhaled smoke particles generated by fire.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.04a
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• pp.245-246
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• 2000

공기중의 오염 입자가 인체에 얼마나 많은 영향을 미치는가는 흡입된 입자 (inhaled particles) 중에서 얼마나 많은 양이 폐 (lung)에 침전되는가와 밀접한 관계가 있다. 또한 정상 및 비정상 (diseased) 폐에서, 흡입된 입자의 침전 위치와 침전양 (deposition site and dose)은 입자의 크기와 호흡 양식(breathing pattern)에 따라 큰 차이를 보이며, 이런 차이는 흡입오염입자 (inhaled pollutant particles)에 의한 건강 위험도 평가 (health risk assessment) 및 흡입용 약물 (inhaled drug aerosols)의 치료효과(therapeutic effects) 평가 등에 큰 영향을 미친다. (중략)

• The Korean Journal of Nuclear Medicine
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• v.26 no.1
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• pp.8-13
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• 1992

Low doses of ionizing radiation from external or internal sources cause heterogeneous distribution of energy deposition events in the exposed biological system. With the cell being the individual element of the tissue system, the fraction of cells hit, the dose received by the hit, and the biological response of the cell to the dose received eventually determine the effect in tissue. The hit cell may experience detriment, such as change in its DNA leading to a malignant transformation, or it may derive benefit in terms of an adaptive response such as a temporary improvement of DNA repair or temporary prevention of effects from intracellular radicals through enhanced radical detoxification. These responses are protective also to toxic substances that are generated during normal metabolism. Within a multicellular system, the probability of detriment must be weighed against the probability of benefit through adaptive responses with protection against various toxic agents including those produced by normal metabolism. Because irradiation can principally induce both, detriment and adaptive responses, one type of affected cells may not be simply summed up at the expense of cells with other types of effects, in assessing risk to tissue. An inventory of various types of effects in the blood forming system of mammals, even with large ranges of uncertainty, uncovers the possibility of benefit to the system from exposure to low doses of low LET radiation. This experimental approach may complement epidemiological data on individuals exposed to low doses of ionizing radiation and may lead to a more rational appraisal of risk.

• Journal of Dental Anesthesia and Pain Medicine
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• v.20 no.5
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• pp.325-329
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• 2020

Classic anesthetic techniques for the inferior alveolar nerve, lingual nerve, and long buccal nerve blockade are achieved by estimating the intended location for anesthetic deposition based on palpation, inspection, and subsequent correlation for oral anatomical structures. The present article utilizes computed tomography (CT) data to 3D print a guide for repeatable and accurate deposition of a local anesthetic at the ideal location. This technical report aims to anatomically define the ideal location for local anesthetic deposition. This process has the potential to reduce patient discomfort, risk of nerve damage, and failed mandibular anesthesia, as well as to reduce the total anesthetic dose. Lastly, as robotic-based interventions improve, this provides the initial framework for robot-guided regional anesthesia administration in the oral cavity.

• Fire Science and Engineering
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• v.21 no.2 s.66
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• pp.64-73
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• 2007

The absorption characteristics of hazardous materials onto human body and defense mechanism differ from each other region within the respiratory tracts, thus adverse health effects of inhaled smokes are associated with not only the concentration but also the location of the particles deposited. In this work, the deposition fraction per surface area and the deposition sites of the smoke particles in human respiratory tracts for each rest and light exercise conditions together with oral and nasal breathing were calculated by using segmental volume tracking method. The results would be used for deriving the amount of absorption of hazardous materials onto human body, thus contribute to the health risk assessments of inhaled fire smokes.