• Korean Journal of Metals and Materials
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• v.48 no.3
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• pp.225-234
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• 2010

Salt bath nitriding, which has been developed recently by domestic company, is an emerging ecofriendly surface treatment. The salt bath nitriding is accompanied by the electrolysis process in the pretreatment step, and this whole processis called Pseudo-Electrolysised Salt bath Nitriding (PESN). The PESN creates only $NH_3$ and non-toxic salts without harmful $CN^{-}$ or toxic gas such as that found in previous salt bath nitriding. In general, ion nitriding and gas nitriding create high hardness and a strong brittle white layer on the surface. However, the PESN shows a thin white and gray layer. The PESN was applied to the defense material, 3%Cr-Mo-V steel, to study the surface characteristics at $480^{\circ}C$, $530^{\circ}C$, and $580^{\circ}C$ for 4 hrs, 20 hrs, 40 hrs, and 60 hrs of nitriding time condition. As a result, the best nitriding layer was found at $530^{\circ}C$ for 40 hrs. If we improve corrosion resistance and nitriding layer depth, the PESN will be able to be applied to the defense industry parts.

• Fire Science and Engineering
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• v.33 no.4
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• pp.28-34
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• 2019

Regardless of the ignition source, the main factors affecting the spread of flames to the human body are combustibles. The sound absorption material, which is the finishing material used in music institutes and karaoke rooms, consists of polyurethane that generates a large amount of toxic gas with a high amount of combustion gases during a fire. Still, the current law does not require the use of impregnated finishing materials for tutoring services with less than 100 users. In this study, the rate of flame diffusion was measured using the MultiRaelite composite gas measuring instrument (target substance VOC, HCHO, SO₂, CO₂, CO, HCN, and NO₂) for the collection of sound-absorbing materials installed in the actual music academy. The results showed that the toxic gas found in this experiment exceeded the allowable concentration of TWA (Time Weighted Average) and STEL (Short Term Exposure Limit). In addition, a comparative combustion test of the general sound absorber and non-combustion sound absorbing materials on the market showed wide differences in ignition and diffusion. Therefore, based on the results of the experiment, private institutes with less than 100 users should be mandated to use non-combustion sound absorbing materials.

• Korean Journal of Clinical Laboratory Science
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• v.42 no.3
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• pp.116-124
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• 2010

This study was aimed to clerify the cytotoxicity of some plant extracts such as Hosta longissima HONDA (HL), Hemerocallis fulva var. Kwanso REGL (HFVK), Hemerocallis fulva L (HF), Macrocapium officinale NAKAI (MO) and Mentha canadensis var. piperascens HARA (MCVP), the cultured NIH3T3 fibroblasts were treated with 25, 50, 100, 150 and $200{\mu}g/mL$ of five kinds of plant extracts for 48 hours, respectively. The cytotoxicity of plant extracts was measured by MTT and NR assays for the cell viability, and XTT assay for the cell adhesion activity. In this study, HL, MO and FHVK extracts showed the range of midtoxic-non toxic by the criteria of chemical cytotoxicity. While, the HF and MCVP extracts showed midtoxic. In the extract cytotoxicity, HL, MO and FHVK extracts showed non-toxic by the criteria of extract cytotoxicity. While, HF extract was determined as lower-toxic. In the responsive sensitivity of each plant extract on colorimetric assays, HF extract was sensitive to mitochondrial enzyme by MTT assay, lysosomal enzyme by NR assay and mitochondrial nucleus by XTT assay. While, MCVP extract was sensitive to mitochondrial enzyme by MTT assay and lysosomal enzyme by NR assay than other assays. While, HL, HFVK and MO extracts were most sensitive to NR assay. Cell culture is one of useful materials in the screening of cytotoxic and recovary effect on the putative chemical agents or plant extract. And also, colorimetric assay is regarded as very useful tools for quantitative measurement of cytotoxic effect on plant extracts in vitro.

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1806-1808
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• 2014

We report the successful preparation of gold nanoparticles (Au NPs) using a novel electroreduction process, which is simple, fast, and environmentally friendly (toxic chemicals such as strong reducing agents are not required). Our process allows for the mass production of Au NPs and adequate particle size control. The Au NPs prepared show high biocompatibility and are non-toxic to healthy human cells. By applying radio-frequency (RF) ablation, we monitored the electro-hyperthermia effect of the Au NPs at different RFs. The Au NPs exhibit a fast increase in temperature to $55^{\circ}C$ within 5 min during the application of an RF of 13 MHz. This temperature rise is sufficient to promote apoptosis through thermal stress. Our work suggests that the selective Au NP-mediated electro-hyperthermia therapy for tumor cells under an RF of 13 MHz has great potential as a clinical treatment for specific tumor ablation.

• Journal of Pharmaceutical Investigation
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• v.30 no.1
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• pp.1-12
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• 2000

Gene therapy is a method for the treatment of diseases with introducing the gene-engineered materials into a patient with gene-deficiency disease (e.g. cystic fibrosis) or cancer to produce a therapeutic protein in a patient's cells. Successful gene therapy requires establishing both gene expression systems and delivery systems. Viral and non-viral vectors have been used for gene delivery. Viral vectors have a high transfection efficiency, but are limited in relations to issues of safety, toxicity and immunogenecity. Non-viral vectors are easy to prepare and relatively safe. However, non-viral vectors have a low transfection efficiency. Cationic liposomes are the most available among non-viral vectors. Cationic liposomes have been used to transfect cells both in vitro and in vivo experiments. Besides, several formulations containing cationic lipid are being used in clinical trials in cases of cystic fibrosis or cancer. A crucial subject to the further development of gene delivery vectors will be a long-term gene expression with following characteristics; protecting and deliverying DNA efficiently, non-toxic and non-immunogenic, and easy to produce in large scale.

• Journal of Ginseng Research
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• v.36 no.4
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• pp.449-460
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• 2012

Plants have versatile detoxification systems to encounter the phytotoxicity of the wide range of natural and synthetic compounds present in the environment. Glutathione S-transferase (GST) is an enzyme that detoxifies natural and exogenous toxic compounds by conjugation with glutathione (GSH). Recently, several roles of GST giving stress tolerance in plants have demonstrated, but little is known about the role of ginseng GSTs. Therefore, this work aimed to provide further information on the GST gene present in Panax ginseng genome as well as its expression and function. A GST cDNA (PgGST) was isolated from P. ginseng cDNA library, and it showed the amino acid sequence similarity with theta type of GSTs. PgGST in ginseng plant was induced by exposure to metals, plant hormone, heavy metals, and high light irradiance. To improve the resistance against environmental stresses, full-length cDNA of PgGST was introduced into Nicotiana tabacum. Overexpression of PgGST led to twofold increase in GST-specific activity compared to the non-transgenic plants, and the GST overexpressed plant showed resistance against herbicide phosphinothricin. The results suggested that the PgGST isolated from ginseng might have a role in the protection mechanism against toxic materials such as heavy metals and herbicides.

• Journal of the Korea Furniture Society
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• v.22 no.1
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• pp.72-81
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• 2011

These days, beds have been developed not as furniture to sleep in but Healthcare Furniture. The function of heating, non-electronic-waves and far-infrared rays have been added. Also, eco-friendly materials such as stone, mud, rubber and wood are combined to them together with the radiation-heating method using heat conduction through electronic coil and hot water circulation. Modern people suffer from stress and fatigue. The hot issue is "health." Focused on the health, the development of design for beds considering the influence electronic waves, anions, deep sleep and the density of toxic materials have on human bodies has become urgent. In this study, the trend, specification and efficiency of the functional health-related electronic coil technology are analyzed. Through the analysis, the environmental standards are set. According to them, technology, eco-friendly materials and additional functions for the development of the design are considered. Also, the government is promoting the IEC international standardization for the Korean traditional floor heating style beds. In preparation for that, we adopted new HPT method technology. It enables non-electronic-waves, low electricity and stable temperature maintenance control for the warm top and the cool bottom. Also, the head boards and the frames of the beds can be separated. Through this separation, the beds can be easily moved or installed. Eco-friendly materials such as Hinoki cypress wood and red clay and the existing tables function are combined to the head boards so they can be used as drawers and display shelves. If they are used as separate items, they can be used as covers. This is how we suggest the design for the heating beds.

• Korean Journal of Environmental Biology
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• v.22 no.4
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• pp.513-518
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• 2004

Pine needle oil and Korean medicinal herbs (KMH) are known as effective therapeutic agents on various blood vessel disease. We have already reported the ameliorative effect of complex of pine needle oil and Korean medicinal herbs against hyperlipidemia. But safety and non - toxicity of pine needle oil and Korean medicinal herbs to normal animal cells have not been studied clearly. In this study, we investigated whether pine needle oil and Korean medicinal herbs show side effects on rat or not. These materials were administered to rats, and subacute toxicity was examined by measuring the hematological values, CBC differentiation, biochemical levels of blood (TP, total protein; albumin; ALP, alkaline phosphotase; AST, aspatate aminotrans- ferase; ALT, alanine aminotransferase; T-Chol., total cholesterol; T-Bil., total bilirubin) and urine analysis, suggesting that the sample have no side effects and cytotoxicity. These results indicate that the complex of pine needle oil and Korean medicinal herbs may effective non- toxic, safety therapeutic agents on hepatocytes and hyperlipidemia.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.195-195
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• 2006

A superior electrophilic substitution reaction medium that is non-toxic, relatively less corrosive, and non-volatile electrophilic substitution reaction to afford high molecular weight linear and hyperbranched polyetherketones (PEK' s) was developed. The system has very strong driving force to give extra ordinary high molecular weight linear and hyperbranched PEK' s. The reaction medium was further extended to prepare various types of copolymers and covalently grafted polymers onto carbon nanotube (CNT) or carbon nanofiber (CNF). By using characteristic hydrophilic nature of the reaction medium, hyperbranched PEK' s could be synthesized from commercially available $A_3\;+\;B_2$ monomers without network formation via selective solubility of the monomers.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.5
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• pp.62-66
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• 2010

Cellulosic materials were dissolved by NMMO(N-methylmorpholine-N-oxide) and CED (Cupriethylene diamine), respectively, to measure their DPs (degrees of polymerization) by using viscometer. We changed cellulose DPs by applying various amounts of low intensity electron-beam radiation to the cellulosic materials. NMMO is environmental-friendly, non-toxic, and biodegradable organic cellulose solvent and used industrially because of its high cellulose dissolving power and high solvent recovery ratio. The cellulose DP measurement results using these two different chemicals were correlated highly ($R^2$ >0.95). It was also found that cellulose with high DP was dissolved more easily in NMMO than CED. In addition, NMMO method gave more higher resolution in the measurement.