• Journal of environmental and Sanitary engineering
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• v.9 no.2
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• pp.101-109
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• 1994

Acute toxicity of heavy metals( mercury, cadmium lead, chromium and copper ), organophosphours insecticides( EPN, 2, 4- D, and parathion ), and other chemicals( arsenic, cyanide, and phenol ) to Daphnia magna was analyzed. Acute toxicity of heavy metals, organophosphours insecticides and other chemicals on Daphnia magna, LC$_{50}$ was showed 0.07-0.73mg/1, 0.22-1.94mg/t and 1.73-39.92mg/1 respectively. Daphnia magna to most of toxic chemicals was sensitive and then it seems to be useful except phenol in toxic test of water. Toxic chemicals were classified as Group 1 which had a high LC$_{50}$ value and the low increase rate of toxicity according to the increase of concentration, Group 2 which had a high LC$_{50}$ value and the high increase rate of toxicity, Group 3 which had a low LC$_{50}$ value and the low increase rate of toxicity. To Daphnia magna, lead, chromium, EPN, and parathion were included in Group 1; Mercury and copper in Group 2; Arsenic and cadmium in Group 3; Cyanide 2,4- D, and phenol in Group 4.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.11a
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• pp.57-70
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• 2006

Microparticle and micropolymer retention and drainage aid systems are powerful tools for paper and board making on a variety of machines. Drawbacks attributed to the current systems sometimes include; apparent high cost, production and quality problems and in some cases a negative effect on formation. The next generation multi-component organic/inorganic systems have demonstrated their ability to decouple the effects of retention and drainage and to improve the formation and print quality for the same retention and in some cases higher retention levels. It is now possible to optimize independently retention, drainage and formation effects with the same high return on investment of current microparticle systems.

• Macromolecular Research
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• v.16 no.7
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• pp.590-595
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• 2008

The pressure driven membrane process has been a breakthrough in the removal of pollutants from drinking water. These experiments examined the removal of chlorophenol compounds from water using low pressure membranes. The removal performance of the membranes was based primarily on size exclusion. Apart from size exclusion, the polarity and pKa of the compounds also influences the membrane performance. The molecular size and dipole moments of the respective molecules were calculated using a quantum chemical method. The rejection of pollutants also followed the same trend as salt rejection by the membranes.

• Bulletin of the Korean Chemical Society
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• v.31 no.4
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• pp.1055-1057
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• 2010

• Bulletin of the Korean Chemical Society
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• v.28 no.11
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• pp.2029-2033
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• 2007

Hydrotalcite, layered double hydroxides (LDH), with hexagonal morphology has been rapidly synthesized by microwave reaction within 1 hour by urea hydrolysis from homogeneous solution. Different synthesis parameters, Mg/Al molar ratio, microwave reaction temperature and microwave power were systematically investigated. Pure hydrotalcite phase was obtained for Mg/Al ratios of 2:1 and 3:1, and higher reaction temperature gave higher crystallinity. The hydrotalcite synthesized at 600W power shows the highest crystallinity and more homogeneous crystal size distribution. The hydrotalcite samples were characterized by powder X-ray diffraction (XRD), simultaneous thermogravimetric/differential thermal analysis (TG/DTA), Fourier Transform Infrared (FT-IR) and Scanning electron micrograph (SEM).

• Korean Journal of Food Science and Technology
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• v.37 no.4
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• pp.685-694
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• 2005

Korean practices in tolerance setting of pesticide residues on food crops were compiled with an effort to harmonize with international standards. Based on scientific data including historical background, limit setting protocols, adoption of ADI values, food factors, nation's body weights, and regulatory margins which are required for the setting of maximum residue limits, necessary measures to be taken by Korean regulatory authorities were proposed.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.6
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• pp.516-521
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• 2006

The use of gltA gene, as a new biomarker for environmental stress biomonitoring, was investigated because of its key position as the first enzyme of the tricarboxylic acid (TCA) cycle. A recombinant bioluminescent Escherichia coli strain, EBJM2, was constructed using a plasmid carrying the citrate synthase (gltA) promoter transcribing the Photorhabdus luminescens IuxCDABE genes (gltA::luxCDABE). The responses from this strain were studied with five different classes of toxicants: DNA damage chemicals, phenolics, oxidative-stress chemicals, PAHs, and organic solvents. EBJM2 responded strongly to DNA damage chemicals, such as mitomycin C (MMC) and methyl-nitro-nitrosoguanidine (MNNG) and nalidixic acid with the strongest responses. In contrast, tests with several compounds from the other four classes of toxicants gave no significant response. Therefore, EBJM2 was found to be sensitive to DNA damage chemicals.

• Proceedings of the Korean Society of Toxicology Conference
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• 2002.11b
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• pp.161-161
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• 2002

The abnormal accumulation of collagen is progressive and often results in impairment of liver function, i.e. liver cirrhosis. Collagen synthesis requires several posttranslational events. Prolyl 4-hydroxylase is the key enzyme in collagen synthesis that catalyzes the hydroxylation of peptide-bound proline residues to 4-hydroxyroline.(omitted)

• Journal of the Korean Applied Science and Technology
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• v.31 no.3
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• pp.517-524
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• 2014

Two key technologies of horizontal drilling and hydraulic fracturing are recognized to achieve the rapid growth of shale gas production, in specific, in the United States during last decade. The claims between environmentalists and oil companies have been debating in terms of water contamination. Nowadays, voluntary publication of chemicals from shale gas players are available in the website, FracFocus. This paper introduces chemicals that are currently used in hydraulic fracturing process. Among chemicals, guar gum and guar derivatives are dominantly consumed to increase the viscosity of hydrofracking fluids. The role of additional additives, such as breakers and biocides, is presented by explaining how they cut down the molecular structure of guar gum and guar derivatives. In addition, crosslinking agent, pH controller, friction reducer, and water soluble polymers are also presented.

• Mass Spectrometry Letters
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• v.9 no.4
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• pp.110-114
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• 2018

Since accumulation of chemicals in deciduous teeth can occur from the second trimester of fetal development to shedding, a deciduous tooth has been considered as an attractive biomatrix for estimating individual chemical exposures recently. Therefore, detection of organic chemicals from teeth has received an increasing attention in exposomics research. Most previous studies on organic chemical analysis of teeth not only focused on a few targeted chemicals but also ignored potential contaminants from an enamel surface or a dental pulp. Recently, our group started developing a multi-class organic analysis method for deciduous teeth and tried to find a proper incubation condition of tooth materials. Our results showed that incubation with methanolic HCl provided the best performance among tested.