• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.6
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• pp.669-674
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• 2017

Paralytic shellfish toxins (PSTs) are produced by marine dinoflagellate phytoplankton Alexandrium spp. and Gymnodinium spp. These toxins accumulate in filter feeding organisms such as bivalves and the ingestion of contaminated shellfish can cause illness in humans. The mouse bioassay (MBA) has been the preferred PST testing method worldwide for more than 50 years. However, this assay has several disadvantages, such as detection limits, non-toxic-profiles, and the ethical issues of using animals. The aim of this study was to establish an alternative to the MBA method for testing for PSTs. We optimized the analysis conditions of a post-column oxidation-high performance liquid chromatography (PCOX-HPLC) method and the Scotia Rapid Test Kit, and then compared the accuracy of these methods to the MBA method. The results demonstrated a strong correlation between the PCOX-HPLC method and the MBA, although the PCOX-HPLC method required expensive equipment and standard material, and was time consuming. The Scotia Rapid Test Kit promises to be a useful tool, as it provided rapid and qualitative results, although the method sometimes gave a false positive result that could not be explained by toxin profiles.

• Journal of Auto-vehicle Safety Association
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• v.8 no.4
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• pp.24-30
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• 2016

In Korea, the Vehicle Dismantler and Recycler industry is supervised by the Ministry of Land, Infrastructure and Transport under the Automobile Management Act. Also, Korean Automotive recycling businesses are supervised by the Minister of Environment under the Resource Recirculation Act. The main concern of the Minister of Environment is how the wastes from Dismantled vehicles will be environmentally removed, stored, treated, recycled or disposed. In 2000, the European Union (EU) adopted the End-of-Life Vehicles Directive (2000/53/EC) which required Members to ensure the collection, treatment and recovery of end-of-life vehicles (ELVs). The Directive, the most tightly regulated and precautionary legal systems, required that the last owner of a vehicle could drop off the ELV at an authorized treatment facility and that the producers of the ELV should pay the cost of the program. The adoption of the ELVs directive has led the development of Automotive Dismantler and Recycler networks to reuse, refurbish, remanufacture, recycle and recover parts and materials embedded in ELVs. Also, the ELVs directive which has had an insignificant impact on Korean manufacturers has strong presence in the European market and has been successfully externalized on them. The Korean manufacturers not only achieve the 85% recycling target set by the ELVs directive but also meet the Extended Producer Responsibility (EPR) which requires manufacturers to contribute dismantling process. In order to improve the Korean vehicle dismantling and recycling system, the Automobile Management Act and the Resource Recirculation Act should be harmonized. Particularly the roles of the Ministry of Land, Infrastructure and Transport and the Minister of Environment should be sharply divided. Like Japan, the ELV management needs to be highly centralized, regulated, and controlled by the ministry specialized in Vehicle, namely the Ministry of Land, Infrastructure and Transport and the sub organizations. Like EU Members, recovery, reuse, and recycling must be distinguished. Recovery is defined as the final productive use of the parts and materials embedded in ELVs, which includes reuse and remanufacture of parts and recycling of the other materials. Dismantling process and reuse and remanufacture of parts must be governed by the Ministry of Land, Infrastructure and Transport. For environmental recycling or disposal of waste materials, such as CFCs, glass and plastic material, and toxic substances, governmental financial support system should be in place.

• Toxicological Research
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• v.31 no.1
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• pp.61-68
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• 2015

The objective of this study was to obtain single oral dose toxicity information for concentrated and lyophilized powder of blue honeysuckle (Lonicera caerulea L., Caprifoliaceae; BHcL) in female and male ICR mice to aid in the process of developing natural origin medicinal ingredients or foods following proximate analysis and phytochemical profile measurement. The proximate analysis revealed that BHcL had an energy value of 3.80 kcal/g and contained 0.93 g/g of carbohydrate, 0.41 g/g of sugar, 0.02 g/g of protein, and 0.20 mg/g of sodium. BHcL did not contain lipids, including saturated lipids, trans fats, or cholesterols. Further, BHcL contained 4.54% of betaine, 210.63 mg/g of total phenols, 159.30 mg/g of total flavonoids, and 133.57 mg/g of total anthocyanins. Following administration of a single oral BHcL treatment, there were no treatment-related mortalities, changes in body weight (bw) or organ weight, clinical signs, necropsy or histopathological findings up to 2,000 mg/kg bw, the limited dosage for rodents of both sexes. We concluded that BHcL is a practically non-toxic material in toxicity potency.

• Journal of the Korean Society of Radiology
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• v.12 no.2
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• pp.173-178
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• 2018

Lead is a very useful material in shielding radiation in hospitals. But lead is toxic. Therefore, there are many studies on substitutable materials, Typically, there are many studies using tungsten. In this study, we investigated the physical properties of lead and tungsten and the Half value layer. As a result, lead having higher atomic number showed higher cross - sectional area than tungsten. But, at the same size, the electron density of tungsten with a high density is about 1.7 times higher than that of lead. In MCNPX simulation, the shielding effect of tungsten is about 1.4 times higher than that of lead, It was confirmed that tungsten had better shielding efficiency than lead. However, considering the economic aspect, tungsten is a rare metal, which is about 25 times more expensive than lead, which is considered to be inappropriate as an alternative to lead.

• Journal of Korean Society on Water Environment
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• v.18 no.3
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• pp.245-251
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• 2002

Reactive dyes waste water, a toxic and refractory pollutant, was treated by an electrochemical method using $Ti/IrO_2$ as anode and Stainless Steel 316 as cathode. In this technique, sodium chloride as an electrolyte was added. A number of experiments were run in a batch system. Artificial samples (reactive blue 19, red 195, yellow 145) were used. Operation parameters, such as supporting electrolyte concentration, current density, pH and sample concentration have been investigated for their influences on COD and color removal efficiencies during electrolysis. After 5 and 90 minites of eletrolysis, color was reduced by 51.5% and 98.9% respectively. Under the condition of current density $10A/dm^2$, NaCl concentration 12mg/l and pH 3, 62.9% of $COD_{Cr}$ was removed after electrolysis for 90 minites. The optimum condition of color removal and COD reduction in this work was found to be the following : pH 3, sodium chloride concentration 20g/l, current density $10A/dm^2$. As a result, we confirmed to be effective to color removal and reduction of refractory organic material.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.15 no.3
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• pp.138-146
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• 2015

Purpose: If early diagnosis is not made, patients with metabolic disorders as homocystinemia rapidly progress to physical defect or mental retardation resulted in storage of the toxic material into the brain. Therefore, it is necessary to develop an analytical method for a rapid screening and/or correct confirmation diagnosis. Methods: The standard solution of sulfur amino acids spiked plasma was subjected to protein precipitation with methanol, and then consecutively derivatized with trimethylsilyl (TMS) and trifluoroacyl (TFA) and determined by GC-MS. The formation of TMS derivative of the hydroxyl and TFA derivative of amino functional group was performed by BSTFA and MBTFA, respectively. Selective ion monitoring (SIM) mode was used for quantification with selected specific ions. Results: A calibration curve on standard spiked pooled plasma showed a linear relationship with correlation coefficient of 0.9936-0.9992 for all compounds over the range of 0.1-300 ng. The precision and accuracy were within S.D. of 1-15% and RSD of 1-15% for intra-day assay at 2 ng/mL, 15 ng/mL and 30 ng/mL. LOD and LOQ was 0.4 ng/mL and 4 ng/mL respectively. Conclusion: A rapid analytical method was developed to quantify sulfur amino acids and methyl malonic acid, after two-step derivatization procedure with good sensitivity and specificity on human plasma. Advantages of a new method are simplicity and rapidity. The method could be useful for routine analysis, diagnosis of homocysteinemia.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.11
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• pp.1471-1476
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• 2011

The catalytic converter in the front part of an automobile's exhaust system converts toxic exhaust gas into nontoxic gas. The substrate in the central part of the converter has a circular or oval-shaped cross section and fine lattice-shaped walls. In the canning process, the substrate is wrapped in mats and inserted into a can. During this process, mat pressure is induced, which may cause brittle fracturing in the substrate. In this paper, a finite element program for determining the mat pressure distribution was developed to avoid these fractures. The program was created in Microsoft EXCEL, so the input and output procedures are relatively simple. It was assumed that the substrate is rigid, the mat is material nonlinear, and the can is linear elastic. The can is modeled as a beam element to resist both bending and uniform tension/compression. The number of elements is fixed to 35, and the number of iterations, to 20. The solutions are compared to ABAQUS solutions and found to be in good agreement.

• Journal of Powder Materials
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• v.22 no.6
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• pp.385-390
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• 2015

We report a synthesis of non-toxic InP nanocrystals using non-pyrolytic precursors instead of pyrolytic and unstable tris(trimethylsilyl)phosphine, a popular precursor for synthesis of InP nanocrystals. In this study, InP nanocrystals are successfully synthesized using hexaethyl phosphorous triamide (HPT) and the synthesized InP nanocrystals showed a broad and weak photoluminescence (PL) spectrum. As synthesized InP nanocrystals are subjected to further surface modification process to enhance their stability and photoluminescence. Surface modification of InP nanocrystals is done at $230^{\circ}C$ using 1-dodecanethiol, zinc acetate and fatty acid as sources of ZnS shell. After surface modification, the synthesized InP/ZnS nanocrystals show intense PL spectra centered at the emission wavelength 612 nm through 633 nm. The synthesized InP/ZnS core/shell structure is confirmed with X-ray diffraction (XRD) and Inductively Coupled Plasma - Atomic Emission Spectrometer (ICP-AES). After surface modification, InP/ZnS nanocrystals having narrow particle size distribution are observed by Field Emission Transmission Electron Microscope (FE-TEM). In contrast to uncapped InP nanocrystals, InP/ZnS nanocrystals treated with a newly developed surface modified procedure show highly enhanced PL spectra with quantum yield of 47%.

• Current Photovoltaic Research
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• v.6 no.1
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• pp.21-26
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• 2018

Beside several advantages, the PV power generation as a clean energy source, is still below the supply level due to high power generation cost. Therefore, the interest in fabricating low-cost thin film solar cells is increasing continuously. $Cu_2O$, a low cost photovoltaic material, has a wide direct band gap of ~2.1 eV has along with the high theoretical energy conversion efficiency of about 20%. On the other hand, it has other benefits such as earth-abundance, low cost, non-toxic, high carrier mobility ($100cm^2/Vs$). In spite of these various advantages, the efficiency of $Cu_2O$ based solar cells is still significantly lower than the theoretical limit as reported in several literatures. One of the reasons behind the low efficiency of $Cu_2O$ solar cells can be the formation of CuO layer due to atmospheric surface oxidation of $Cu_2O$ absorber layer. In this work, atomic layer deposition method was used to remove the CuO layer that formed on $Cu_2O$ surface. First, $Cu_2O$ absorber layer was deposited by electrodeposition. On top of it buffer (ZnO) and TCO (AZO) layers were deposited by atomic layer deposition and rf-magnetron sputtering respectively. We fabricated the cells with a change in the deposition temperature of buffer layer ranging between $80^{\circ}C$ to $140^{\circ}C$. Finally, we compared the performance of fabricated solar cells, and studied the influence of buffer layer deposition temperature on $Cu_2O$ based solar cells by J-V and XPS measurements.

• The Journal of Engineering Geology
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• v.21 no.4
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• pp.393-402
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• 2011

Asbestos is a toxic material that can lead to lung cancer and other diseases. There is no information regarding areas in Korea that contain asbestos in nature; consequently we need to manage such areas with care. The purpose of this study was to construct a local graded map of asbestos exposure risk based on the natural occurrence of asbestos in rocks. We first developed a means of evaluating the asbestos exposure risk and produced thematic maps based on a field survey. In addition, we constructed a knowledge base for asbestos through analysis, representation and processes about asbestos data and prepare for the development of an evaluation model for asbestos exposure risk. The spatial analysis of asbestos exposure risk is based on a weighted-overlay analysis using expert opinion and the literature, and a fuzzy-overlay analysis using the uncertainty in the data. The map of asbestos exposure risk, compiled according to the weighted and fuzzy operations, is expected to be used to ensure safety and to reduce the risk of exposure to asbestos.