• The Journal of Korean Academy of Prosthodontics
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• v.41 no.5
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• pp.606-616
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• 2003

Purpose : The purpose of this study was to research the properties of some chemically cured methacrylate polymers such as MMA, HEMA, TEG-DMA, bis-GMA, GMA. Material and Method : 5 kinds of methacrylates were selected and added 2% tertiary amine and benzoyl peroxide to make a chemically curable polymer 25 micron crushed silicas which are treated with silane were selected as filler, they were added into methacrylate monomer until the consistency did not changed by the load of 500gram. All of the experimental resins were 5 kinds, and a serial test was done with 3 kinds of items including the filler contents, the tensile strength, and the bond strength. The number of specimen were 10 for each group. Filler contents were obtained by reducing the specimens to ashes at $600^{\circ}C$ for 1 hour. The specimens with the dimension of 6mm in diameter and 3mm thick were immersed in $37{\pm}1^{\circ}C$ distilled water for 24 hours before test, and tensile strength were measured with cross-head speed 1mm/min. Shear bond strength were mea sured on the specimens attached to bovine enamel etched with 37% phosphoric acid for 1 minute. Results : 1. Maximum filler incorporation was the highest as 75.5% on MMA, and the least as 53.4% on bis- GMA(p<0.0001). 2. The tensile stregth were MMA 141.3, GMA 154.3, TEG-DMA 157.4, bis-GMA 161.4 MPa, and HEMA showed the highest value, 226.9MPa(p = 0.0004). 3. The bond strength were GMA 10.1, TEG-DMA 11.7, HEMA 12.2, bis-GMA 13.3 MPa, and MMA showed the highest value, 15.3MPa, however statistical significances were not (p =0.3838), 4. TEG-DMA and HEMA were not different on the aspect of maximum filler contents and shear bond strength(p>0.05). Conclusion : HEMA can be used as an another diluent substituting TEG-DMA with the increased strength and with the constant bond strength and the constant filler contents.

• Journal of Environmental Health Sciences
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• v.42 no.6
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• pp.438-449
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• 2016

Objectives: Exposure to airborne bacteria is associated with adverse health effects such as respiratory and infectious diseases. This study evaluated airborne bacterial concentrations in the living rooms, kitchens, and toilets of 30 homes. Methods: Bacteria were sampled with an MAS100 impactor in three spaces in the subject homes between April 2014 and February 2015. Bacteria were grown on TSA plates for 48 hours at $35^{\circ}C$. The bacterial strains were isolated and amplified by polymerase chain reaction. Results: The most culturable bacteria were found in toilets ($624.0CFU/m^3$, GM: $417.3CFU/m^3$), followed by in the kitchen ($503.8CFU/m^3$, GM: $324.9CFU/m^3$). The dominant genera identified were: Staphylococcus sp.(19%), Micrococcus sp.(16%), and Bacillus sp.(11%) in the indoor air and Bacillus sp. (30%) in the outdoor air. Gram-positive bacteria comprised more than half of all colonies. Conclusion: In this study, culturable bacteria concentrations were higher than those reported in other spaces. Therefore, it is important to control relative humidity and remove moisture to prevent bacteria from multiplying. Additionally, the dominant species in indoor air were Staphylococcus sp. and Micrococcus sp. These are found on the human skin, mucous membranes, and hair, so human activity can affect bacterial distribution. Therefore, cleaning and controlling moisture are important for reducing indoor bacterial concentrations.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.40-44
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• 2003

Soil-borne infectious disease including Pythium aphanidermatum and Rhizoctonia solani causes severe damage to plants, such as cucumber. This soil-borne infectious disease was not controlled effectively by chemical pesticide. Since these diseases spread through the soil, chemical agents are usually ineffective. Instead, biological control, including antagonistic microbe can be used as a preferred control method. An efficient method was developed to select an antagonistic strain to be used as a biological control agent strain. In this new method, surface tension reduction potential of an isolate was included in the ‘decision factor’ in addition to the other factors, such as growth rate, and pathogen inhibition rate. Considering these 3 decision factors by a statistical method, an isolate from soil was selected and was identified as Bacillus sp. GB16. In the pot test, this strain showed the best performance among the isolated strains. The lowest disease incidence rate and fastest seed growth was observed when Bacillus sp. GB16 was used. Therefore this strain was considered as plant growth promoting rhizobacteria (PGPR). The action of surface tension reducing component was deduced as the enhancement of wetting, spreading, and residing of antagonistic strain in the rhizosphere. This result showed that new selection method was significantly effective in selecting the best antagonistic strain for biological control of soil-borne infectious plant pathogen. The antifungal substances against P. aphanidermatum and R. solani were partially purified from the culture filtrates of Bacillus sp. GB16. In this study, lipopeptide possessing antifungal activity was isolated from Bacillus sp. GB16 cultures by various purification procedures and was identified as a surfactin-like lipopeptide based on the Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), high performance liquid chromatography mass spectroscopy (HPLC-MS), and quadrupole time-of-flight (Q-TOF) ESI-MS/MS data. The lipopeptide, named GB16-BS, completely inhibited the growth of Pythium aphanidermatum, Rhizoctonia solani, Penicillium sp., and Botrytis cineria at concentrations of 10 and 50 mg/L, respectively. A novel method to prevent the foaming and to provide oxygen was developed. During the production of surface active agent, such as lipopeptide (surfactin), large amount of foam was produced by aeration. This resulted in the carryover of cells to the outside of the fermentor, which leads to the significant loss of cells. Instead of using cell-toxic antifoaming agents, low amount of hydrogen peroxide was added. Catalase produced by cells converted hydrogen peroxide into oxygen and water. Also addition of corn oil as an oxygen vector as well as antifoaming agent was attempted. In addition, Ca-stearate, a metal soap, was added to enhance the antifoam activity of com oil. These methods could prevent the foaming significantly and maintained high dissolved oxygen in spite of lower aeration and agitation. Using these methods, high cell density, could be achieved with increased lipopeptide productivity. In conclusion to produce an effective biological control agent for soil-borne infectious disease, following strategies were attempted i) effective screening of antagonist by including surface tension as an important decision factor ii) identification of antifungal compound produced from the isolated strain iii) novel oxygenation by $H_2O_2-catalase$ with vegetable oil for antifungal lipopeptide production.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.2
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• pp.163-170
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• 2011

The nutritional properties and biological activities of leaves and stems of Gaeddongssuk (Artemisia annua L.) were investigated. Contents of moisture, crude lipid and crude protein were significantly higher in the leaves, and then ash, crude fiber and mineral were significantly higher in the stems. Contents of total phenols and flavonoids of leaves were about 2 fold higher than those of stems. Antioxidant activity was significantly increased in a dose-dependent manner; also, water and ethanol extracts of leaves were stronger than those of stems. Especially, DPPH radical scavenging activity, reducing power and tyrosinase inhibition activity were significantly higher in leaves extracts than stems extracts of Gaeddongssuk. But, ${\alpha}$-glucosidase inhibition activity was higher in stem than its leaves extract. In MTT assay by human breast adenocarcinoma cell line MCF-7 and MDA-MB-231, ethanol extracts of leaves showed the highest anticancer activity; the rates of growth inhibition were 76.26% and 52.59% on MCF-7 and MDA-MB-231 cells, at the concentration of $250\;{\mu}g$/mL, respectively. In conclusion, biological activities of extracts from Gaeddongssuk were dependent on the fiber, phenolic and flavonoid content.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.3
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• pp.363-368
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• 2013

The nutrients and antioxidative activities of fruits and leaves from Metasequoia glyptostroboides were investigated to provide basic data for the future development of functional foods. The nitrogen-free extract contents of fruit and leaves were 69.04% and 50.47%, respectively. Total phenolic content was higher in leaves (21.75 mg/GAE g) compared to the fruit (19.95 mg/GAE g). The mineral components of fruit and leaves mainly consisted of calcium (2,136.08 and 304.85 mg/100 g, respectively), potassium (1,355.53 and 1,144.04 mg/100 g, respectively), and phosphorous (426.30 and 350.50 mg/100 g, respectively). In terms of amino acid composition, aspartic acid, glutamic acid, proline, and leucine were relatively high, but methionine and cystine were low. The hot water extract from leaves was a more potent free radical-scavenger and had higher reducing activities than extracts from fruit. Thus, phenolics of M. glyptostroboides leaves can be utilized as an effective functional food substance for its natural antioxidant properties.

• Economic and Environmental Geology
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• v.35 no.6
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• pp.553-565
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• 2002

Seasonal variations in vertical distributions of metals were investigated in the contaminated paddy soils around Siheung Cu-Pb-Zn and Deokeum Au-Ag mines. Geochemical behavior of metals was also evaluated with respect to redox changes during the cultivation of rice. Two microcosms simulating the rice-growing paddy field were set up in the laboratory. The raw paddy soils from two sites showed differences in mineralogy, metal concentrations and gecochemical parameters, and it is suggested that high proportions of exchangeable fractions in metals may give high dissolution rates at Deokeum. In both microcosms of Siheung and Deokeum, redox differences between surface and subsurface of paddy soils were maintained during the flooded period of 18 weeks. Siheung soil had neutral to alkaline pH conditions, while strongly acidic conditions and high Eh values were found at the surface soil of Deokeum. The concentrations of dissolved Fe and Mn were higher in the subsurface pore waters than in interface and upper waters from both microcosms, indicating reductive dissolution under reducing conditions. On the contrary, dissolved Pb and Zn had high concentrations at the surface under oxidizing conditions. From the Siheung microcosm, release of dissolved metals into upper waters was decreased. presumably by the trap effect of Fe- and Mn-rich layers at the interface. However, in the Deokeum microcosm, significant amounts of Pb and Zn were released into upper water despite the relatively lower contents in raw paddy soil, and seasonal variations in the chemical fractionation of metals were observed between flooded and drained conditions. Under acidic conditions, rice may uptake high amounts of metals from the surface of paddy soils during the flooded periods, and increases of exchangeable phases may also increase the bioavailability of heavy metals in the drained conditions.

• Economic and Environmental Geology
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• v.45 no.2
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• pp.137-144
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• 2012

Soil pan typically presents the problems in soil water movement or in aeration which is not appropriate for a plant root growth, In this study physico-chemical characteristics of soils and micromorphological characteristic of clay accumulated zone were investigated to identify redox characteristic and evolution of a fragipan of Gangreung series commonly developed in coastal terraces. Gangreung series is classified as Aquic Fragiudalfs according to the USDA soil taxonomy. It is known that sedimentary ocean floor results in soil pan having parallel liner soil structure due to landscape evolution around 200 to 250 million years ago. it is considered that illite, kaolinite, and vermiculite are major clay minerals contained in a fragipan of Gangreung series. Mixed gray and reddish brown colored band around soil pores was found and would be the redoxmorphic features of fragipan. It is possibly due to accumulated illuvial clay and ferriargillans in soil pores and aggregates in reducing conditions eluding ferrous material. Therefore, mixed colored band around pores in soils of Gangreung series would be developed from the eluted ferrous materials which were accumulated in fragipan during the emerged land formation.

• Applied Chemistry for Engineering
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• v.27 no.1
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• pp.21-25
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• 2016

When copper alloy is used in etching process for the production of lead frame, the high concentration of heavy metals, such as iron, nickel and zinc may be included in the etching waste. Those etching waste is classified as a specified one. Therefore a customized design was designed for the purification process of the lead frame etching waste liquid containing high concentrations of heavy metals for the production of an electroplating copper(II) oxide. Since the lead frame etching waste solution contains highly concentrated heavy metal species, an ion exchange method is difficult to remove all heavy metals. In this study, a copper(I) chloride was manufactured by using water solubility difference related to the reduction-oxidation method followed by the reunion of copper(II) chloride using sodium sulfate as an oxidant. The hydrazine was chosen as a reducing agent. The optimum added amount was 1.4 mol per 1.0 mol of copper. In the case of removal of heavy metals by using the combination of reduction-oxidation and ion exchange resin methods, 4.3 ppm of $Fe^{3+}$, 2.4 ppm of $Ni^{2+}$ and 0.78 ppm of $Zn^{2+}$ can be reused as raw materials for electroplating copper(II) oxide when repeated three times.

• Journal of Life Science
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• v.22 no.6
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• pp.844-851
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• 2012

Antioxidant and cancer cell growth inhibition activity of hot water extract from five different varieties of Artemisia (A. Argyi H., A. iwayomogi Kitamura, A. Princeps Var Orien talis HARA, A. princeps Pampanini and A. annua L.) in Korea was studied. We determined the phenol and flavonoid contents and examined antioxidant assay, such as DPPH, NO radical scavenging, activity ferric-reducing antioxidant power (FRAP), and bleaching inhibition activity in the ${\beta}$-carotene linolic acid system. Also, we performed HeLa and MCF-7 cancer cell growth inhibition assay of Artemisia extracts. Total phenol and flavonoid contents were the highest in A. iwayomogi Kitamura followed by A. Argyi H. DPPH radical scavenging activity was the highest in A. Argyi H. at 50 ${\mu}g/ml$ concentration, NO radical scavenging activity was more than 50% in A. Princeps Var Orien talis HARA, A. princeps Pampanini, and A. annua L. at 200 ${\mu}g/ml$ concentration. FRAP was higher in A. Argyi H. and A. iwayomogi Kitamura. Antioxidant activity in the ${\beta}$-carotene linolinolic system was also higher in A. Argyi H. and A. iwayomogi Kitamura by 60.50% and 56.90% at 100 ${\mu}g/ml$ concentration, respectively. In cancer cell growth inhibition activities at 400 ${\mu}g/ml$ concentration, A. iwayomogi Kitamura showed greater than 80% on HeLa cell. A. princeps Pampanini and A. Argyi H. extract had growth inhibition activities greater than 80% on MCF cell. The results of this study suggest that the antioxidant and anticancer activities in various Artemisia are a promising source of functional food ingredients.

• The Korean Journal of Food And Nutrition
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• v.18 no.1
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• pp.63-71
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• 2005

Panax ginseng leaves are produced as the by-product when Panax ginseng roots were harvested. The Panax ginseng leaves was examed for the applicable possibility as the functional food. In this study, the changes in chemical composition of Panax ginseng leaves was examed by three methods as the hot-air dried(DRT), the aged tea(AGT) and the heat processed tea(HPT). The general composition of Panax ginseng leaves tea was shown as similar results in 3 different process methods. The level of the crude lipid and reducing sugar concentration were decreased slightly in HPT. The free sugar content of DRT was higher than the HPT and AGT. The existence of the higher content of free sugar composition in order are sucrose, fructose and glucose. The concentration of serine was the highest in the free amino acids, which were shown from 309.6 mg% to 336.6 mg%. The contents of free amino acid in Panax ginseng leaves made by DRT was higher than by AGT and HPT. The concentration of Ca was shown as the highest content among the minerals and was 2,115 mg%. The contents of minerals were existed in order of Ca, K, Mg, P, Na, Mn, Fe, Zn and Cu. But there were hardly any remarkable differences of mineral concentrations of Panax ginseng leaves tea made by different processing methods. The concentration of water soluble solid of Panax ginseng leaves tea processed by HPT was higher than by DRT and AGT. The concentration of ascorbic acid was shown the highest value of 424.4mg% in HPT. There was no differences in the fatty acid composition according to their processing methods. The concentration of palmitic acid was higher than that of other fatty acid. The order of fatty acid concentration were palmitic aicd, linoleic acid, linolenic acid, oleic acid and stearic acid, abundantly. As a conclusion, HPT was shown as the best process method for the production of Panax ginseng leaves tea.