• YAKHAK HOEJI
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• v.54 no.2
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• pp.142-149
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• 2010

Development of alternative testing methods for the replacement of hazardous reagents with less hazardous ones is strongly enforced because exposure of human and environment to hazardous reagents are restricted and hazardous reagents are gradually prohibited from using in various testing methods. Thus, in this study, we developed 8 monographs from the Korean Pharmaceutical Codex by substituting the use of the hazardous reagents including ICH class 1 such as benzene, chloroform and dioxane to the use of less toxic ones like ICH class 2 or 3 reagents. We also improved their qualification and quantification performance. Among 8 monographs, the 6 newly developed TLC methods for the identification of nifedipine, oxolamine citrate, ketoprofen lysinate, chlorquinaldol, retinol acetate, and riboflavin showed a clear spot of corresponding material without any interference in spite of the replacement with ICH class 2 or 3 reagents. For the quantification of domperidone and trimebutine, HPLC methods were developed for the substitution of UV/VIS spectrometry and titrimetry, respectively. These HPLC methods were validated for the linearity, recovery, reproducibility, and inter-laboratory variations. In conclusion, the newly developed methods could be expected to become valuable tools for revising the Korean Pharmaceutical Codex.

• Korean Journal of Construction Engineering and Management
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• v.19 no.4
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• pp.43-51
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• 2018

As the inventory of aged apartments is expected to increase explosively, the importance of maintenance to improve the durability of concrete facilities is increasing. Concrete compressive strength is a representative index of durability of concrete facilities, and is an important item in the precision safety diagnosis for facility maintenance. However, existing methods for measuring the concrete compressive strength and determining the maintenance of concrete facilities have limitations such as facility safety problem, high cost problem, and low reliability problem. In this study, we proposed a model that can predict the concrete compressive strength through images by using deep convolution neural network technique. Learning, validation and testing were conducted by applying the concrete compressive strength dataset constructed through the concrete specimen which is produced in the laboratory environment. As a result, it was found that the concrete compressive strength could be learned by using the images, and the validity of the proposed model was confirmed.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.3
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• pp.447-456
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• 2018

Elemental carbon (EC) and organic carbon (OC) thermal/optical methods for the analysis of ambient particulate matter were used to analyze twenty-two $PM_{2.5}$ samples along collected from May 28 to June 20 of 2016 at the Anmyeon measurement site ($36.32^{\circ}N$; $126.19^{\circ}E$). The three laboratory OCEC protocols, which are the National Institute of Occupational Safety and Health (NIOSH5040), the Interagency Monitoring of Protected Visual Environments_A(IMPROVE_A), and European Supersites for Atmospheric Aerosol Research2 (EUSAAR2), were utilized for the aerosol characterization experiment as in intercomparisons between three protocols. There are excellent agreement for total carbon (i.e. sum of EC and OC), but statistically significant differences were observed in the split between the measured EC and OC. IMPROVE_A EC values were always larger than both NIOSH5040 and EUSAAR2 protocols. These methods exhibited significantly different temperature-distributions based on thermogram analysis, which is normalized to total carbon. In this study, a protocol for carbonaceous analysis is suggested for the Korean Peninsula.

• Journal of Radiation Protection and Research
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• v.26 no.4
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• pp.399-408
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• 2001

The variation characteristics of radon concentration, equilibrium equivalent concentration and equilibrium factor in some houses and laboratory buildings have been studied. The variation of equilibrium factor and the unattached fraction of radon progeny with ventilation condition have been also estimated. The averages of radon concentration, equilibrium equivalent concentration and equilibrium factor were $30\;Bq\;m^{-3},\;19.6\;Bq\;m^{-3}$ and 0.65 in seven houses, while $55.0\;Bq\;m^{-3},\;31.9\;Bq\;m^{-3}$ and 0.58 in three laboratory buildings, respectively. The diurnal variation of radon concentration, equilibrium equivalent concentration and equilibrium factor in indoor showed a typical pattern that the radon concentration, equilibrium equivalent concentration and equilibrium factor increased at dawn and morning, while decreased at midday and evening. While the equilibrium factor rate deceased in the indoor environment which was well ventilated, the unattached traction of radon progeny increased. The equilibrium factor was in proportion to air pressure and humidity of indoor, whereas in Inverse proportion to temperature.

• Journal of Environmental Health Sciences
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• v.42 no.2
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• pp.112-117
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• 2016

Objectives: In this study, we investigated the biodegradation rates of 8 perfluorooctanesulfonate (PFOS) alternatives synthesized at the at Changwon National University in comparison to those of PFOS potassium salt and PFOS sodium salt. Methods: A biodegradability test was performed for 28 days with microorganisms cultured in the good laboratory practice laboratory at the Korea Environment Corporation following the OECD Guidelines for the testing of chemicals, Test No. 301 C Results: While $C_5H_8F_3SO_3K$, $C_8F_{17}SO_3K$ and $C_8F_{17}SO_3Na$ were not degraded after 28 days, the 3 alternatives were biodegraded at the rates of 31.4% for $C_8H_8F_9SO_3K$, 25.6% for $C_{10}H_8F_{13}SO_3K$, 23.6% for $C_{25}F_{17}H_{32}S_3O_{13}Na_3$, 20.9% for $C_{15}F_9H_{21}S_2O_8Na_2$, 15.5% for $C_{23}F_{18}H_{28}S_2O_8Na_2$, 8.5% for $C_{17}F_9H_{25}S_2O_8Na_2$ and 4.8% for $C_6H_8F_5SO_3K$. When the concentration was the same(500 mg/L), $C_{23}F_{18}H_{28}S_2O_8Na_2$ had the lowest tension with 20.94 mN/m, which was followed by $C_{15}F_9H_{21}S_2O_8Na_2$ (23.36 mN/m), $C_{17}F_9H_{25}S_2O_8Na_2$ (27.31 mN/m), $C_{25}F_{17}H_{32}S_3O_{13}Na_3$ (28.17 mN/m), $C_{10}H_8F_{13}SO_3K$ (29.77 mN/m) and $C_8H_8F_9SO_3K$ (33.89 mN/m). Having higher surface tension of 57.64 mN/m and 67.57 mN/m, respectively, than those of the two types of PFOS salts, $C_6H_8F_5SO_3K$ and $C_5H_8F_3SO_3K$ were found valueless as substitute for PFOS. Conclusion: The biodegradation test suggest that 6 compounds could be used as substitutes for PFOS. $C_{23}F_{18}H_{28}S_2O_8Na_2$ and $C_{15}F_9H_{21}S_2O_8Na_2$ were found to be the best substitutes based on biodegradation rate and surface tension, followed by $C_{25}F_{17}H_{32}S_3O_{13}Na_3$, $C_8H_8F_9SO_3K$ and $C_{10}H_8F_{13}SO_3K$. $C_{17}F_9H_{25}S_2O_8Na_2$ was found to have relatively low value as an alternative but it still had a potential to substitute the conventional PFOS.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.3
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• pp.402-413
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• 2001

Food safety is a term broadly applied to food quality that may adversely affect human health. These include zoonotic diseases and acute and chronic effects of ingesting natural and human-made xenobiotics. There are two major areas of concern over the presence of residues of antibiotics in animal-derived foodstuffs with regard to human health. The first is allergic reactions. Some antibiotics, such as penicillins can evoke allergic reactions even though small amounts of them are ingested or exposed by parenteral routes. The second is development of antibiotic resistance in gut bacteria of human. Recently multi-resistant pneumococcal, glycopeptide-resistant enterococci and gram negative bacteria with extended-spectrum $\beta$-lactamases have spread all over the world, and are now a serious therapeutic problem in human. Although it is evident that drugs are required in the efficient production of meat, milk and eggs, their indiscriminate use should never be substituted for hygienic management of farm. Drug should be used only when they are required. In addition to veterinary drugs, environmental contaminants that were contaminated in feed, water and air can make residues in animal products. Mycotoxins, heavy metals, pesticides, herbicides and other chemicals derived from industries can be harmful both to animal and human health. Most of organic contaminants, such as dioxin, PCBs and DDT, and metals are persistent in environment and biological organisms and can be accumulated in fat and hard tissues. Some of them are suspected to have endocrine disrupting, carcinogenic, teratogenic, immunodepressive and nervous effects. The governmental agencies concerned make efforts to prevent residue problems; approval of drugs including withdrawal times of each preparation of drugs, establishment of tolerances, guidelines regarding drug use and sanitation enforcement of livestock products. National residue program is conducted to audit the status of the chemical residues in foods. Recently HACCP has been introduced to promote food safety from farm to table by reducing hazardous biological, chemical and physical factors. Animal Production Food Safety Program, Quality Assurance Programs, Food Animal Residue Avoidance Databank are para- or non-governmental activities ensuring food safety. This topic will cover classification and usage or sources of chemical residues, their adverse effects, and chemical residue status of some countries. Issues are expanded to residue detection methodologies, toxicological and pharmacokinetic backgrounds of MRL and withdrawal time establishments, and the importance of non-governmental activities with regard to reducing chemical residues in food.

• Journal of Environmental Science International
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• v.25 no.4
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• pp.505-516
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• 2016

With the development of nanotechnology, nanomaterials are used in various fields. Therefore, the interest regarding the safety of nanomaterial use is increasing and much effort is diverted toward establishment of exposure assessment and management methods. Occupational exposure limits (OELs) are effectively used to protect the health of workers in various industrial workplaces. This study aimed to propose an OEL for domestic multi-walled carbon nanotubes (MWCNTs) based on animal inhalation toxicity test. Basic procedure for development of OELs was examined. For OEL estimation, epidemiological study and quantitative risk assessment are generally performed based on toxicity data. In addition, inhalation toxicity data-based no observed adverse effect level (NOAEL) and benchmark dose (BMD) are estimated to obtain the OEL. Three different estimation processes (NEDO in Japan, NIOSH in USA, and Baytubes in Germany) of OELs for carbon nanotubes (CNTs) were intensively reviewed. From the rat inhalation toxicity test for MWCNTs manufactured in Korea, a NOAEL of $0.98mg/m^3$ was derived. Using the simple equation for estimation of OEL suggested by NEDO, the OEL of $142{\mu}g/m^3$ was estimated for the MWCNT manufacturing workplace. Here, we used test rat and Korean human data and adopted 36 as an uncertainty factor. The OEL for MWCNT estimated in this work is higher than those ($2-80{\mu}g/m^3$) suggested by previous investigators. It may be greatly caused by different physicochemical properties of MWCNT and their dispersion method and test rat data. For setting of regulatory OELs in CNT workplaces, further epidemiological studies in addition to animal studies are needed. More advanced technical methods such as CNT dispersion in air and liquid should be also developed.

• Journal of the Korean Geosynthetics Society
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• v.20 no.4
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• pp.19-32
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• 2021

In this study, evaluation and consideration of domestic/overseas design, construction, and quality control performed by the authors on the deep cement mixing method were performed, and improvements for the development of the DCM method were suggested in the future. As a result of this study, it was found that the cross-sectional area correction for strength is required during the laboratory test of mix proportion, and caution is required because the extrapolation method may lead to different results from the actual one. Applicable design methods should be selected in consideration of both the improvement ratio and the type of improvement during design, and it was confirmed that the allowable compressive strength to which the safety factor was applied refers to the standard value for stability review and not the design parameters. In the case of the stress concentration ratio, rather than applying a conventional value, it was possible to perform economical design by calculating the experimental and theoretical stress concentration ratio reflecting the design conditions. In the case where pre-boring is expected during construction, if the increased water content is not large compared to the original, there were cases where a major problem did not occur even if the result that did not consider the increase in water content was used. In addition, it was confirmed that when the ratio of the top treatment length to the improved length is high, a small amount of design cement contents per unit length can be injected during construction. In the case of quality control, it was evaluated that D/4~2D/4 for single-axis and D/4 point for multi-axis were optimal for coring of grouting mixtures. As an item for quality control, it is judged that the standard that considers the TCR along with the unconfined compressive strength of grouting mixtures is more suitable for the domestic situation.

• Proceedings of the Korean Environmental Health Society Conference
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• 2005.06a
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• pp.240-248
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• 2005

To implement a globally harmonized system of classification and labeling of chemicals (GHS) in Korea, an interminsterial GHS working group involving 6 ministries established an expert working group composed of 7 experts from relevant organizations and one private consultant to prepare an officialKorean GHS version by March, 2005. As such, the translation and review of the official Korean GHS version, including annexes, started in October, 2004 and was completed on March 15, 2005. The official Korean GHS version has now been posted on the websites of the relevant ministries and organizations to solicit public opinions. The official Korean GHS version will be finalized after a public hearing scheduled forMay, 2005. Collaborative efforts as regards implementing and disseminating the GHS in Korea will be continued to avoid any confusion or duplication and for effective use of resources. The globally harmonized system of classifying and labeling chemicals (GHS) was originally adopted in 1992 at the United Nations Conference on Environment and Development (UNCED), as subsequently reflected in Agenda 21 chapter 19. The work was coordinated and managed under the auspices of the Interorganization Programme for the Sound Management of Chemicals(IOMC) Coordinating Group for the Harmonization of Chemical Classification Systems (UNCEGHS). The technical focal points for completing the work were the International Labour Organization (ILO); Organization for Economic Cooperation and Development (OECD); and United Nations Economic and Social Council's Subcommittee of Experts on the Transport of Dangerous Goods (UNSCETDG). The work was finalized in October 2002, and the World Summit on Sustainable Development in Johannesburg on 4 September 2002 encouraged countries to implement the new GHS as soon as possible with a view to having the system fully operational by 2008 (UN, 2003). Implementation has already started with pilot countries introducing the system to their national practices in different regions of the world. The GHS text, called the purple book, becameavailable as a W publication in early 2003. The GHS text, called the purple book, becameavailable as a UN publication in early 2003. The GHS system will be kept dynamic, and regularly revised and made more efficient as experience is gained in its implementation. While national or regional governments are the primary audiences for this document, it also contains sufficient context and guidance for those in industry who will ultimately be implementing the national requirements that will be introduced (UN, 2003). The Japanese government published their official Japanese GHS version, the first in Asia, in April 2004 after starting work in January 2003 based on an interministerial chemical coordination committee involving 7 ministries, including the Ministry of Foreign Affairs, Ministry of Internal Affairs and Communications, Ministry of Health, Labour, and Welfare, Ministry of Agriculture, Forestry and Fisheries, Ministry of Economy, Trade and Industry, Ministry of Land, Infrastructure, and Transport, and Ministry of Environment (MOE, 2004). Accordingly, similar to the Japanese GHS efforts, this paper presents the interministerial efforts involved in publishing the official Korean GHS version.

• Journal of the Korean Chemical Society
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• v.61 no.2
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• pp.51-56
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• 2017

N-nitrosamines are the nitroso compounds which are produced by nitrosation reactions of the secondary amine and nitrite under acidic conditions. Approximately 300 species of N-nitrosamine have been tested for carcinogenicity in laboratory experiments, with 90% of them demonstrated carcinogenic effects different animal species, including higher primates. In 1978, IARC classified NDMA and NDEA as Group 2A, and NDPA, NDBA, NPIP, NPYR and NMOR as Group 2B. In this study, we established pretreatment and analytical method for N-nitrosamines (NDMA, NDEA, NMEA, NDPA, NDBA, NPIP, NPYR and NMOR) in human urine for biological monitoring of N-nitrosamines. The analytes were extracted using solid phase extraction (SPE), then quantitative analysis was performed by LC-(APCI)-MS/MS. The accuracies of the established method were between 85.8~108.7% and precisions were lower than 20%. The limit of detection (LOD) were between 0.0002 (NDBA) and 0.0793 (NDMA) ng/ml. The linearity obtained was satisfying for the 8 N-nitrosamines, with a coefficient of determination ($r^2$) higher than 0.999. The mean concentrations of N-nitrosamines in the urine were 2.645 mg/g creatinine for NDMA, 0.067 mg/g creatinine for NDEA, 0.009 mg/g creatinine for NMEA, 0.011 mg/g creatinine for NDBA, 0.271 mg/g creatinine for NPIP and 0.413 mg/g creatinine for NPYR. NDPA and NMOR were not detected. It can be used as a instrumental methodology for evaluation and risk assessment of human exposure to N-nitrosamines for the further research.