• Journal of Preventive Medicine and Public Health
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• v.30 no.1 s.56
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• pp.77-101
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• 1997

In September 1994, residents of Gozan-dong, Incheon City, made a petition to the government about their health problems which might be caused by previous glass fibre landfill nearby 'H' company. In february 1995, at regular academic meeting of occupational and environmental medicine, a research team of 'D' University presented that they had found glass fibres in groundwater of the area through their survey. They were suspicious of probable association between ingestion of groundwater contaminated with glass fibres and skin tumors among residents. A joint research team was formed and carried out the survey of environment concerning groundwater and its glass fibre existence, and health assessment of residents in the area and industrial workers of 'H' company during May to November, 1995. Analysis of groundwater flow system indicates that the flow lines from the glass fibre landfill pass through or terminate at the 6 houses around the landfill. This means that the groundwater of the 6 houses around the glass fibre landfill could be affected by some possible contaminants from the landfill, but the groundwater quality of the other houses was irrelevant to the landfill. The qualitative and qualitative analyses for glass fibres in 54 groundwater samples including those from the nearby 6 houses, were carried out using SEM equipped with EDS, resulting in no evidence for the presence of glass fibres in the waters. Major precipitates, formed in waters while boiling, were identified as calcium carbonates, in particulary, aragonites in needle form. The results of health assessments of 889 residents in Gozan-dong, participated in this study, showed statistically significant differences in past medical histories of skin tumor and respiratory disease between the exposed group (31 persons who inhabited in 6 houses around the landfill) and the control group, but no significant differences in past medical histories of other diseases, such as cancer mortality, current gastroscopic findings, current skin diseases and respiratory diseases, etc. Also, we could not prove any glass fibres in excised specimens of 9 skin tumors in both groups and there were no health problems possibly associated with glass fibres in employees of the 'H' company. After all, we could not authenticate the association, raised by prior investigators, between groundwater streams, assumedly contaminated with glass fibres or not, and specific disease morbidities or common disease/symptom prevalences. That is, we could not find any glass fibres in groundwater as the only exposure factor of this study hypothesis, and there were not enough certain evidences such as increasing disease prevalences, for examples, skin, respiratory and gastrointestinal diseases etc, possibly related to glass fibre exposure, in exposed group. As a matter of course, the conditions for confirming causal association, for example, strength of the association, consistency of the association, specificity of the association, temporality of the association and dose-response relationship etc, have not been satisfied. In conclusion, we were not able to certify the hypothesis that contamination of groundwater with glass fibres might cause any hazardous health effects in residents who used it for drinking.

• Development and Reproduction
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• v.15 no.2
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• pp.87-98
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• 2011

The present experiment was performed to evaluate the osteogenic differentiation of human adipose tissue derived mesenchymal stem cells (ATMSCs) seeded in bioceramic-poly D,L-latic-co-glycolic acid (PLGA) scaffold. Osteogenic differentiation of ATMSCs were induced using the osteogenic induction (OI) medium. ATMSCs were cultured with OI medium during 28 days in well plate. The proliferation of ATMSCs in OI medium group was significantly increased for 14 days of plate culture but slowed after 21 days. On the other hand, proliferation in the control group showed constant increase for 28 days of culturing. The alkaline phosphatase (ALP) activity of ATMSCs in OI medium group increased during the 21 days of culture but decreased on 28 days. However, in control group ALP activity of ATMSCs was continuously decreased as time goes. Nodule was observed at 21 days of culture in OI medium group and confirmed accumulation of calcium in cell by alizarin red staining. ATMSCs were seeded in PLGA scaffold or in Bioceramic-PLGA scaffold, and cultured with OI medium. ALP activity of ATMSCs by osteoblast differentiation in each scaffold increased on 21 days of culture and decreased rapidly on 28 days. ALP activity of ATMSCs was increased highly in Bioceramic-PLGA scaffold compared to PLGA scaffold on 21 days of culturing. SEM-EDS analysis demonstrated that calcium and phosphate content and Ca/P ratio in Bioceramic-PLGA scaffold increased higher than in PLGA scaffold. Biodegradability of scaffold at 56 days after implantation showed that Bioceramic-PLGA scaffold was more biodegradable than PLGA scaffold. The results demonstrated that the differentiation of ATMSCs to osteoblast were more effective in scaffold culture than well plate culture. Bioceramic increased cell adhesion rate on scaffold and ALP activity by osteoblast differentiation. Also, bioceramic was considered to increase the calcium and phosphate in scaffold when ATMSCs was mineralized by osteogenic differentiation. Bioceramic-PLGA scaffold enhanced the osteogenesis of seeded ATMSCs compared to PLGA scaffold.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.3
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• pp.171-178
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• 2008

Metal filter elements were newly introduced to the high temperature filter(HTF) system in the low- and intermediate-level radioactive waste vitrification plant. In order to evaluate the performance of various metal materials as filter media, elements made of AISI 316L, AISI 904L, and Inconel 600 were included to the test set of filter elements. At the visual inspection to the elements performed after completion of each test, a few dark spots were observed on the surface of some elements. Especially they were found much more at the AISI 316L elements than others. To check the dark spots are the corrosion phenomena or not, two kinds of analyses were performed to the tested filter elements. Firstly, the surfaces or the cross sections of filter specimens cut out from both normal area and dark spot area of elements were analyzed by SEM/EDS. The results showed that the dark spots were not evidences of corrosion but the deposition of sodium, sulfur and silica compounds volatilized from waste or molten glass. Secondly, the ring tensile strength were analyzed for the ring-shape filter specimens cut out from each kind of element. The result obtained from the strength tested showed no evidence of corrosion as well. Conclusionally, depending on the two kinds of analysis, no evidences of corrosion were found at the tested metal filter elements. But the dark spots formed on the surface could reduce the effective filtering area and increase the overall pressure drop of HTF system. Thus, continuous heating inside filter housing up to dew point will be required normally. And a few long-period test should be followed for the exact evaluation of corrosion of the metal filter elements.

• Journal of the Mineralogical Society of Korea
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• v.22 no.3
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• pp.241-248
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• 2009

Kaolinite was synthesized from amorphous $SiO_2$ and $Al(OH)_3{\cdot}xH_{2}O$ as starting materials by hydrothermal reaction conducted at $250^{\circ}C$ and $30\;kg/cm^2$. The acidity of the solution was adjusted at pH 2. The synthesized kaolinite was characterized by XRD, IR, NMR, FE-SEM, TEM and EDS to clarify the formational process according to the reaction time from 2 to 36 hours. X-ray diffraction patterns showed after 2 h of reaction time, the starting material amorphous $Al(OH)_3{\cdot}xH_{2}O$ transformed to boehmite (AlOOH) and after the reaction time 5 h, the peaks of boehmite were observed to be absent thereby indicating the crystal structure is partially destructed. Kaolinite formation was identified in the product obtained after 10 h of reaction and the peak intensity of kaolinite increased further with reaction time. The results of TGA and DTA revealed that the principal feature of kaolinite trace are well resolved. TGA results showed 13 wt% amount of weight loss and DTA analysis showed that exothermic peak of boehmite observed at $258^{\circ}C$ was decreased gradually and after 10 h of reaction time, it was disappeared. After 5 h of the reaction time, the exothermicpeak of transformation to spinel phase was observed and the peak intensiy increased with reaction time. The results of FT-IR suggested a highly ordered kaolinite was obtained after 36 hours of reaction. It was identified by the characteristic hydroxide group bands positioned at 3,696, 3670, 3653 and $3620\;cm^{-1}$. The development of the hydroxyl stretching between 3696 and $3620\;cm^{-1}$, depends on the degree of order and crystalline perfection. TEM results showed that after 15 h reaction time, curved platy kaolinite was observed as growing of (001) plane and after 36 h, the morphology of synthetic kaolinite exhibited platy crystal with partial polygonal outlines.

• Economic and Environmental Geology
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• v.51 no.4
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• pp.323-343
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• 2018

This study defines the mineralogical, micro-textural and geochemical characteristics for the carbonate rocks and discusses the fluids that have affected the depositional environment of the Lower Makgol Formation in Seokgaejae section. Based on analysis of X-ray Diffraction (XRD), Scanning Electron Microscope-Energy Dispersive X-ray Spectrometry (SEM-EDS), Electron Probe Micro Analyzer-Wavelength Dispersive X-ray Spectrometry (EPMA-WDS) and Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS), carbonate miorofacies in the basal and the lower members of the Makgol Formation are distinguished and classified into four types. Type 1 dolomite (xenotopic interlocking texture) and Type 2 dolomite (idiotopic interlocking texture) have relatively high Mg/Ca ratio, flat REE pattern, low Fe and Mn. Extensively interlocking textures in these dolomites indicate constant supply of Mg ion from hypersaline brine. Type 3 and Type 4 dolomite (scattered and loosely-aggregated texture) have relatively moderate Mg/Ca ratio, MREE enriched pattern, low to high Fe and Mn. These partial dolomitization indicate limited supply of Mg ion under the influx of meteoric water with seawater. Also, the evidence of Fe-bearing minerals, recrystallization and relatively high Fe and Mn in Type 4 indicates the influence of secondary diagenetic fluids under suboxic conditions. Integrating geochemical data with mineralogical and micro-textural evidence, the discrepancy between the basal and the lower members of the Makgol Formation indicates different sedimentary environment. It suggest that hypersaline brine have an influence on the basal member, while mixing meteoric water with seawater have an effect on the lower member of the Makgol Formation.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.16 no.2
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• pp.183-193
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• 2018

Currently, the Korea Atomic Energy Research Institute (KAERI) is planning to build the Ki-Jang Research Reactor (KJRR) in Ki-Jang, Busan. It is important to safely dispose of low-level radioactive waste from the operation of the reactor. The most efficient way to treat radioactive waste is cement solidification. For a radioactive waste disposal facility, cement solidification is performed based on specific waste acceptance criteria such as compressive strength, free-standing water, immersion and leaching tests. Above all, the leaching test is important to final disposal. The leakage of radioactive waste such as $^{137}Cs$ causes not only regional problems but also serious global ones. The cement solidification method is simple, and cheaper than other solidification methods, but has a lower leaching resistance. Thus, this study was focused on the development of cement solidification for an enhancement of cesium leaching resistance. We used Zeolite and Loess to improve the cesium leaching resistance of KJRR cement solidification containing simulated KJRR liquid waste. Based on an SEM-EDS spectrum analysis, we confirmed that Zeolite and Loess successfully isolated KJRR cement solidification. A leaching test was carried out according to the ANS 16.1 test method. The ANS 16.1 test is performed to analyze cesium ion concentration in leachate of KJRR cement for 90 days. Thus, a leaching test was carried out using simulated KJRR liquid waste containing $3000mg{\cdot}L^{-1}$ of cesium for 90 days. KJRR cement solidification with Zeolite and Loess led to cesium leaching resistance values that were 27.90% and 21.08% higher than the control values. In addition, in several tests such as free-standing water, compressive strength, immersion, and leaching tests, all KJRR cement solidification met the waste acceptance or satisfied the waste acceptance criteria for final disposal.

• Journal of Life Science
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• v.17 no.12
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• pp.1701-1708
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• 2007

Seed pelleting is generally conducted in order to save the labor for sowing and thinning by enabling the precision mechanical planting. In the present study, the influence of physical and chemical properties of pelleting solid materials was investigated on carrot seed germination. Among the pelleting solid materials evaluated, dialite, kaolin, and talc showed low bulk density and high porosity. Bentonite and dialite carried high water holding capacities of 184% and 173%, respectively, while calcium carbonate, calcium oxide, and fly ash showed relatively low water holding capacity. The pH of kaolin (6.8) and dialite (7.4) were close to neutral, while limestone (12.8), calcium oxide (13.0), and bentonite (10.0) were highly basic. High electro-conductivity was shown in limestone and calcium oxide. EDS analysis revealed that the main elemental compositions of talc were Si (71.0%) and Mg (29.0%), and those of calcium carbonate were Ca (66.6%), Si (22.9%), and Mg (10.5%). High granulation capacity was observed from talc and the mixture of talc and calcium carbonate. Seeds pelleted with bentonite showed the highest hardness. The dissolving type of the pellet layer after imbibition was split type in talc, limestone, zeolite, and fly ash, melt type in calcium carbonate and calcium oxide, and swell type in bentonite and vermiculite. The shortest dissolving time of pellet layer was observed from calcium carbonate and kaolin. The germination speed $(T_{50})$ was delayed as the size of pelleted seeds increased. The optimum size of pelleting was 19 ratio in carrot.

• Journal of The Korean Society of Clinical Toxicology
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• v.18 no.2
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• pp.57-65
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• 2020

Purpose: Since 2012, acetaminophen can be accessed easily not only at pharmacies but also at convenience stores. The relationship between the easy access of acetaminophen and the risk of poisoning has been controversial. Several studies also reported different results regarding the risk of acetaminophen poisoning after access to acetaminophen was relaxed. This study examined the long-term effects on the risk of acetaminophen poisoning after easy access to acetaminophen was implemented. Methods: This was a retrospective analysis of an emergency department (ED)-based in-depth Injury Surveillance Cohort by the Korea Center for Disease Control and prevention from 2011 to 2018. Poisoning cases were selected from the Cohort, and the incidence of acetaminophen poisoning and the characteristics of the cases of acetaminophen poisoning were analyzed. The purchase path and the amount of ingestion in acetaminophen poisoning were sub-analyzed from data of six EDs. Results: Of 57,326 poisoning cases, 4.0% (2,272 cases) were acetaminophen poisoning. Of 2,272 cases of acetaminophen poisoning, 42.8% (974 cases) required in-patient care after ED management. Two hundred and sixty-four of these 964 cases required intensive care. The rates of cases that required in-patient treatment and the rates of cases that required intensive care increased from 29.4% in 2011 to 48.1% in 2018, and from 3.1% in 2011 to 15.2% in 2018, respectively (p<0.001, p<0.001). In the poisoning group with in-depth toxic surveillance (n=15,908), the incidence and proportion of acetaminophen (AAP) poisoning increased from 55 cases per year to 187 cases per year and 4.9% to 6.1%, respectively (p=0.009, p<0.001, respectively). The most common age group of acetaminophen poisoning was teenagers, which is different from the most common age group of other pharmaceutical agents: the middle age group of 40-49 years (p<0.001). Of 15,908 in-depth toxic surveillance patients, 693 patients had AAP poisoning, of whom 377 cases (54.2%) purchased acetaminophen from a non-pharmacy. The proportions of the purchase path from non-pharmacy were 41.4% at 2011-12 and 56.4% (2013-18) (p=0.004). The amount of acetaminophen ingestion was 13.5±14.3 g at 2011-12 and 13.9±15.1 g at 2013-18 (p=0.794). Conclusion: Although the incidence of acetaminophen poisoning did not increase remarkably in the short term after the implementation of the new regulation, the incidence of acetaminophen poisoning has increased slightly during the study period of 2017-18. In addition, the proportion of the purchase path from non-pharmacies has increased since the emergence of new regulations for the easy access of acetaminophen in 2012. The incidence of acetaminophen poisoning might have been affected after the increasing accessibility of acetaminophen in convenience stores. Continuous control of acetaminophen poisoning is required. Furthermore, the prevention of acetaminophen poisoning should be focused on teenagers with specialized school education programs.