Gyeongnam National University of Science and Technology is a national university located in Jinju, South Korea. Wikipedia.
Nam S.,Gyeongnam National University of Science and Technology |
Jang H.W.,University of California at Davis |
Shibamoto T.,University of California at Davis
Journal of Agricultural and Food Chemistry | Year: 2012
The antioxidant activity of essences of teas prepared from mulberry (Morus alba L.), Camellia sinensis L., and Cudrania tricuspidata (Carr.) Burea plant was examined using two antioxidant assays. Selected volatile chemicals identified in these plants were also tested for antioxidant activity. All extracts exhibited antioxidant activity with a clear dose response in the aldehyde/carboxylic acid and the malonaldehyde/gas chromatography (MA/GC) assays. Antioxidant activity of extracts at the level of 500 μg/mL ranged from 77.02 ± 0.51% (stems of Burea plant) to 52.57 ± 0.92% (fermented tea of Camellia and stems of Mulberry tea) in the aldehydes/carboxylic acid assay. Their antioxidant activity at the level of 160 μg/mL ranged from 76.17 ± 0.27% (roots of Burea plant) to 59.32 ± 0.27% (stems of Mulberry tea) in the MA/GC assay. Among the positively identified compounds (11 terpenes and terpenoids, 15 alkyl compounds, 26 nitrogen containing heterocyclic compounds, 9 oxygen containing heterocyclic compounds, 18 aromatic compounds, 7 lactones, 6 acids, and 4 miscellaneous compounds), eugenol, 2,5-dihydroxyl acetophenone, and isoeugenol exhibited antioxidant activity comparable to that of BHT in both assays. Vanillin and 2-acetylpyrrole showed potent antioxidant activity in the aldehydes/carboxylic acid assay but only moderate activity in the MA/GC assay. These results suggest that consumption of antioxidant-rich beverages prepared from these plants may be beneficial to human health. © 2012 American Chemical Society.
Choi D.S.,Korea University |
Choi D.S.,University of California at Davis |
Hong J.K.,Gyeongnam National University of Science and Technology |
Hwang B.K.,Korea University
Planta | Year: 2013
Osmotin or osmotin-like protein, a PR-5 family member, is differentially induced in plants by abiotic and biotic stresses. Here, we demonstrate that the pepper (Capsicum annuum) osmotin-like protein 1 gene, CaOSM1, was required for the defense and hypersensitive cell death response and oxidative burst signaling during Xanthomonas campestris pv. vesicatoria (Xcv) infection. CaOSM1 protein was localized to the plasma membrane in leaf cells of Nicotiana benthamiana. Agrobacterium-mediated transient expression of CaOSM1 in pepper distinctly induced the hypersensitive cell death response and H2O2 accumulation. Knock-down of CaOSM1 in pepper by virus-induced gene silencing increased the susceptibility to Xcv infection, which was accompanied by attenuation of the cell death response and decreased accumulation of H2O2. CaOSM1 overexpression in transgenic Arabidopsis conferred reduced susceptibility and accelerated cell death response and H2O2 accumulation to infection by Pseudomonas syringe pv. tomato and Hyaloperonospora arabidopsidis. Together, these results suggest that CaOSM1 is involved in cell death and oxidative burst responses during plant defense against microbial pathogens. © 2013 Springer-Verlag Berlin Heidelberg.
Jung S.,Samsung |
Choo Y.G.,Gyeongnam National University of Science and Technology |
Ji T.,Chonnam National University
IEEE Electron Device Letters | Year: 2012
A lift-off process for direct photolithographic top-contact organic thin-film transistors (TFTs) has been developed using a bilayer of polyvinyl alcohol and SU8. Top-contact pentacene TFTs fabricated by this method, with a fixed channel width of 300 μm but different channel lengths varying from 10 to 80 μm, exhibited mobility values in the range of 0.01-0.03 cm -2V̇s with the average of 0.021 ±0.007 cm -2 V̇s. It is expected that the adoption of SU8 with a high aspect ratio enables the easy fabrication of submicrometer channel devices, giving rise to improved carrier transport characteristics. © 2012 IEEE.
Kim I.-S.,Gyeongnam National University of Science and Technology |
Yang M.,Gyeongnam National University of Science and Technology |
Lee O.-H.,Kangwon National University |
Kang S.-N.,Gyeongnam National University of Science and Technology
LWT - Food Science and Technology | Year: 2011
Stevia rebaudiana (SR), a chrysanthemum herb, has been used as a vegetable-based sweetening additive in health drinks and in other foods. This study was conducted to investigate the antioxidant activity and the bioactive compounds found in water extracts taken from SR leaves and calli. Analysis of vitamins in the leaves showed that folic acid (52.18 mg/100 g) was a major component, followed by vitamin C. The total phenolic and flavonoid contents were found to be 130.76 μg catechin and 15.64 μg quercetin for leaves and 43.99 μg catechin and 1.57 μg quercetin for cellus at mg of water extracts, respectively. Pyrogallol was the major material among the phenolic compounds in both leaf and callus extracts. Furthermore, our results showed that the leaf extracts contained higher amounts of free radicals, hydroxyl radicals and superoxide anion radical scavenging activities than those of the callus extracts. © 2010 Elsevier Ltd.
Roh J.,Gyeongnam National University of Science and Technology
Journal of the Korean Wood Science and Technology | Year: 2016
Medicine herb residues boards were manufactured by using medicine herb residues, and emission properties of volatile compounds from boards were examined under various temperature conditions. The volatile compounds were identified with analysis of TD GC/MS by absorbing their flavor components in Tenax tubes. Total 88 volatile compounds were identified from the board. The number of identified compounds at temperature conditions of 25°C, 35°C, and 45°C were 44, 55, and 65 kinds, respectively. The number of volatile compounds and the total peak area tended to increase with an increase in the temperature. The number of the flavor components detected in all temperature conditions were 34 kinds. Hydrocarbon compounds showed 93% of the detected flavor compounds at 25 °C, 92% at 35°C, and 90% at 45 °C. Ether compounds accounted for 4% and ketone, aldehyde, and acid-type compounds were detected in a small quantity. The hydrocarbons were composed of 17 kinds of monoterpenes and 39 kinds of sesquiterpenes, which accounted for 11% and 80%, respectively. The most detected compound of monoterpene was limonene, and the major flavor components of sesquiterpenes were α-curcumene, zingiberene, β-elemene, β-selinene, α-amorphene, and α-copaene. Anethole (3.26%) known for ether compounds was detected considerably in all temperature conditions. The results suggest that the manufactured medicine herb residues board include various types of flavor compounds and the flavor compounds might be useful for the manufacture of various products.
Yoon S.-L.,Gyeongnam National University of Science and Technology
Palpu Chongi Gisul/Journal of Korea Technical Association of the Pulp and Paper Industry | Year: 2011
This research was performed to investigate the physical and mechanical properties of Chanhoji manufactured with the traditional method. This research would provide a basic information for its application in the manufacture of Korean-style house. A piece of Changhoji was manufactured to have a weight of 3.75 g. The weight was increased with the basic weight and no increase was not found on its density. The strength properties of Changhoji are superior to a copying paper, and the quality showed the first grade in Korean Standard (KS M 7301). The air resistance varied with the thickness from 2 to 19 seconds, but it showed better performance than a copying paper having 38 seconds. This research would be used for the practical use in understanding the ventilation and lightening properties of windows and doors in Korean-style house.
Lee J.H.,NAKDONG River Basin Environmental Office |
Cho K.M.,Gyeongnam National University of Science and Technology
Food Chemistry | Year: 2012
Changes in compositional components of black soybeans, including isoflavone, anthocyanin, protein, oil, and fatty acid, were investigated for the first time in soybeans maintained at room temperature for different storage periods. Isoflavone and anthocyanin profiles in hydrolysed extracts were characterised by column chromatography and HPLC-DAD-ESI/MS spectrometry analysis. These components decreased markedly during storage, whereas protein, oil, and fatty acid showed a slight decrease. The individual isoflavones and anthocyanins observed in black soybeans were as follows, in order of abundance: genistein > daidzein > glycitein; cyanidin-3-O-glucoside > dephinidin-3-O-glucoside > petunidin-3-O-glucoside. In particular, genistein (518.4 → 415.7 → 274.8 μg/g) and cyanidin-3-O-glucoside (6.53 → 2.92 → 1.49 mg/g) showed the greatest decrease for a storage time of two years. The scavenging activities of DPPH and ABTS radicals during storage also decreased in comparison with those of observed before storage. Our results can be used to improve our understanding of the relationship between storage times and the components from black soybeans. © 2011 Elsevier Ltd. All rights reserved.
Yoo C.G.,Iowa State University |
Lee C.W.,Gyeongnam National University of Science and Technology |
Kim T.H.,Iowa State University
Biomass and Bioenergy | Year: 2011
A two-stage process using aqueous ammonia and hot-water has been investigated to fractionate corn stover. To maximize hemicelluloses recovery and purity in the liquid hydrolyzate by optimizing the fractionation process, the experiments were carried out employing response surface methodology (RSM). A central composite design (CCD) was used to evaluate and confirm the effectiveness and interactions of factors. The optimal fractionation conditions were determined to be as follow: (1) First-stage reactor operated in batch mode using a 15% NH4OH solution (wNH3 = 15%) at 1:10 solid:liquid ratio, 60 °C, and 24 h; (2) second stage percolation reactor operated using hot-water at 20 cm3 min-1, 200 °C, and 10 min.The model predicted 51.5% xylan recovery yield and 82.4% xylan purity under these conditions. Experiments confirmed the maximum xylan recovery yield and purity were 54.7% and 83.9% respectively under the optimal reaction conditions.With the solids resulting from the two-stage treatment, 87%-98% glucan digestibilities were obtained with 15 FPU of GC 220 per g-glucan and 30 CBU of Novo 188 per g-glucan enzyme loadings. Xylan digestibility of xylooligomer hydrolysates reached 76% with 8000 GXU per g-xylan of Multifect-Xylanase loading. In the simultaneous saccharification and fermentation (SSF) test using treated solids and Saccharomyces cerevisiae (D5A), 86 % to 98% of ethanol yield was obtained on the basis of the glucan content in the treated solids. © 2011 Elsevier Ltd.
Bolan N.S.,University of South Australia |
Kunhikrishnan A.,National Academy of Agricultural Science |
Choppala G.K.,University of South Australia |
Thangarajan R.,University of South Australia |
Chung J.W.,Gyeongnam National University of Science and Technology
Science of the Total Environment | Year: 2012
There have been increasing interests in the conversion of organic residues into biochars in order to reduce the rate of decomposition, thereby enhancing carbon (C) sequestration in soils. However energy is required to initiate the pyrolysis process during biochar production which can also lead to the release of greenhouse gasses. Alternative methods can be used to stabilize C in composts and other organic residues without impacting their quality. The objectives of this study include: (i) to compare the rate of decomposition among various organic amendments and (ii) to examine the effect of clay materials on the stabilization of C in organic amendments. The decomposition of a number of organic amendments (composts and biochars) was examined by monitoring the release of carbon-dioxide using respiration experiments. The results indicated that the rate of decomposition as measured by half life (t 1/2) varied between the organic amendments and was higher in sandy soil than in clay soil. The half life value ranged from 139days in the sandy soil and 187days in the clay soil for poultry manure compost to 9989days for green waste biochar. Addition of clay materials to compost decreased the rate of decomposition, thereby increasing the stabilization of C. The half life value for poultry manure compost increased from 139days to 620, 806 and 474days with the addition of goethite, gibbsite and allophane, respectively. The increase in the stabilization of C with the addition of clay materials may be attributed to the immobilization of C, thereby preventing it from microbial decomposition. Stabilization of C in compost using clay materials did not impact negatively the value of composts in improving soil quality as measured by potentially mineralizable nitrogen and microbial biomass carbon in soil. © 2012 Elsevier B.V.
Kwak T.-S.,Gyeongnam National University of Science and Technology
Journal of the Korean Ceramic Society | Year: 2012
This study has been focused on properties of mirror surface grinding technology by ELID(Electrolytic In-process Dressing) for metal matrix ceramic composites using in high precision mirror for optics. The experimental studies have been carried out to get mirror surface by grinding for composites, Al-SiC, Al-graphite and Mg-SiC. Grinding process is carried out with varying abrasive mesh type, depth of cut and feed rate using diamond wheel. The machining result of the surface roughness and condition of ground surface, have been analyzed by use of surface roughness tester and SEM measurement system. ELID grinding technology could be applied successfully for the mirror-surface manufacturing processes in spite of ductility of metal matrix material. As the results of experiments, surface roughness of Al-SiC(45 wt%) has been the most superior in these experimental work-pieces as 0.021 μm Ra.