• Bulletin of the Korean Chemical Society
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• v.8 no.4
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• pp.225-230
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• 1987

The redox properties of 2-mercaptopyridine N-oxide (mpno) and its oxovanadium complex, $VO (mpno)_2$ have been studied by the use of polarography and cyclic voltammetry. The radical anion of mpno is generated in acetone and is adsorbed to the electrode to form an adsorption wave at -0.21 V vs Ag/AgCl electrode. The normal wave appeared at -0.50 V is attributed to the formation of radical anion. The $VO (mpno)_2$ exhibits one oxidation wave at +0.57 V, and two reduction waves at -1.07 V and -1.76 V vs. Ag/AgCl electrode; the oxidation is fully reversible one-electron process ($VO (mpno)_2\;{\leftrightarrow}\;VO(mpno)_2^+ + e).$ The reduction wave at -1.07 V is quasireversible and is arised from the formation of $VO (mpno)_2^-.$ The second reduction wave at -1.76 V is irreversible and this reduction process consists of two one-electron steps. The sulfur containing ligands seem to enhance the stability of lower oxidation state of vanadium while the oxygen or nitrogen donor of the ligands stabilize the higher oxidation state of vanadium when comparisons are made among several oxovanadium complexes.

• Journal of English Language & Literature
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• v.56 no.2
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• pp.255-276
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• 2010

Despite some critics' efforts to highlight Shelley's political fruitfulness, they tend to disregard meaningful differences that Shelley has from other Jacobin radicals of his times. Accordingly, the critics tackle his apparent incoherence revealed in A Philosophical View of Reform; the first two sections contain a keen insight into the socio-political injustice prevalent in Britain and the reasons behind it, while the third section withdraws from the previous radical position and settles with a moderate electorate reform. This paper argues that recent developments in post-structuralist and post-Marxist theory help to clearly assess Shelley's political position. Emphasizing that the Jacobin concept of revolution is incompatible with the plurality and opening which a radical democracy requires, post-marxists such as Ernest Laclau and Chantal Mouffee claim that a more viable form of political resistance is to expose repression and force involved in hegemonic articulations. For them, dislocation, a distabilization of a discourse that results from the emergence of events which cannot be domesticated, symbolized, or integrated within the discourse, opens up the possibility of freedom for agents. A Philosophical View of Reform is an attempt to dislocate the discourses of monarchy and paper money by exposing their social and historical constructiveness and their repressive exclusion of alternative discourses. The political goal of this essay is to awaken subjects within a hegemonic structure by decentering the structure and to make them act by stimulating new discoursive constructions.

• Natural Product Sciences
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• v.5 no.2
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• pp.80-84
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• 1999

Peroxynitrite is a cytotoxic intermediate produced by the reaction between the superoxide anion radical and nitric oxide. Flavonoids (afzelin, quercitrin and quercetin 3-O-sambubioside), and chlorogenic acid and its methyl ester obtained from leaves of loquat (Eriobotrya japonica) have recently been shown to scavenge 1,1-diphenyl-2-picrylhydrazyl radical and to inhibit lipid peroxidation in mouse liver homogenate. The aim of this study is to investigate the inhibitory effects of the above components on peroxynitrite produced stimulated by 3-morpholinosydnonimine (SIN-1) to produce superoxide anion radical and nitric oxide at the same time. In addition, the present study tests whether or not the components directly scavenge peroxynitrite itself. The results showed that the components with the aromatic ortho-dihydroxyl groups (catechol) were more potent inhibitors of peroxynitrite formation by SIN-1. In particular, the methyl ester form of chlorogenic acid showed the most potent inhibition. At $5\;{\mu}M$ concentration, the order of minimizing peroxynitrite formation were : methyl chlorogenic acid > quercitrin > quercetin 3-O-sambubioside > chlorogenic acid > afzelin. Authentic peroxynitrite was directly scavenged by the components in a manner similar to peroxynitrite formation by SIN-1. In particular, when compared with penicillamine as a positive control, methyl chlorogenate was as effective in inhibiting peroxynitrite formation and approximately 2 times more effective in scavenging an authentic peroxynitrite. These results demonstrate therefore, that components extracted from the leaves of Eriobotrya japonica effectively scavenged peroxynitrite.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.6
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• pp.836-841
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• 2014

Physiological activities of extracts form Pleurotus cornucopiae were examined. DPPH radical scavenging activity of water extract was 70.22 percent at 4 mg/mL, which was the highest among all extracts. Total polyphenol content of water extract was 26.34 mg/g, which was the highest value for all extraction conditions. Superoxide anion radical scavenging activities ranged from 50.17 to 80.56 percent at 1, 2, and 4 mg/mL, which were higher than the ascorbic acid activity (56.19% at 10 mg/mL) (P<0.05). ACE inhibitory activities were higher in ethanolic extracts than in water extracts. Nitrite-scavenging abilities under acidic conditions (pH 1.2 and pH 3.0) were the most effective among all the extracts. These results will be useful for understanding the physiological activities of Pleurotus cornucopiae.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.7
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• pp.1563-1568
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• 2003

The introduction of invasive marine species of living things into new environments by ship's ballast water, attached to ships' hulls and via other vectors has been identified as one of the four greatest threats to the world's oceans by Global Environment Facility(GEF). Making use of the new technology of alpha-AL$_2$O$_3$ dielectric barrier layer, the strong electric-field gas discharge was introduced and obtained between micro-gap electrodes at high pressure (∼105㎩) of $O_2$ in air and $H_2O$ in seawater. The mixed air with $H_2O$ could be ionized and dissociated into large numbers of activated particles of OH, $O_2$＋, O(1D), HO$_2$ and so on, and then dissolved into the ballast water to form dissolved hydroxyl radical with the concentration of ∼20mg/L. Therefore, the invasive marine species was treated effectively through the hydroxyl radical dissolved pipeline of ballast water by strong electric -field discharge.

• Membrane Journal
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• v.31 no.4
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• pp.268-274
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• 2021

One of the chronic problems in the issue of global warming is the emission of greenhouse gases. Carbon dioxide (CO₂), which accounts for the highest proportion of various greenhouse gases, has been continuously researched by humans to separate it. From this point of view, a poly(vinyl alcohol) (PVA)-based copolymer with acrylic acid monomer was utilized in a gas separation membrane in this study. We employed a free radical polymerization to fabricate PVA-g-PAA (VAA) graft copolymer. It was utilized in the form of a composite membrane on a polysulfone substrate. The proper amount of acrylic acid reduced the crystallinity of PVA and increased CO₂ solubility in separation membranes. In this perspective, we suggest the novel approach in CO₂ separation membrane area by grafting and solution-diffusion.

• Korean Journal of Agricultural Science
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• v.50 no.2
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• pp.219-230
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• 2023

Calla lily is one of the most iconic and widely recognized ornamental plants. This study compared the extracts of 11 cultivars of domestic calla lily bred by the National Institute of Horticultural and Herbal Science for their total polyphenol and antioxidant activities. Eleven cultivars were evaluated for their growth and flowering characteristics as per the Manual for Agricultural Investigation Rural Development Administration (RDA) form. The antioxidant activities were measured using 2,2'-azinobis (3-ethylbebzothiazoloine-6-sulfonic acid)-diammounium salt (ABTS⁺) and 1,1-diphenyl-2-picrrylhydrazyl (DPPH) radical scavenging effect. The plants have an average height of 63.80 ± 5.4 cm, average flower diameter of 7.2 ± 1.1 cm, and width of 12.4 ± 1.7 cm. On average, the diameter and width of leaves were 33.7 ± 3.5 cm and 20.0 ± 1.4 cm, respectively. Extracts of flowers and leaves in the 11 cultivars of white calla lily were compared for their antioxidant activities and total polyphenol contents. ABTS⁺ and DPPH radical scavenging, which are indicative of antioxidant activity, were higher in flowers than in leaves. When comparing by cultivar, we found that 'White Egg' showed the highest antioxidant activity in both the flowers and the leaves. Additionally, we found that by part, the content of total polyphenols was highest in flowers, and by cultivar, it was highest in the 'Swan' and 'White Egg' cultivars. Furthermore, the days to flowering showed correlations with ABTS⁺ radical scavenging, total phenolic contents (TPC), and total flavonoid contents (TFC). Our results indicate that calla lily can be used as breeding material material according to its growth characteristics and as a natural antioxidant source.

• Journal of the Korean Vacuum Society
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• v.6 no.1
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• pp.9-19
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• 1997

The reaction mechanisms of dry cleaning with UV-excited chlorine radical for Zn, Fe and Ti trace contaminants on the Si wafer have been studied by SEM, AFM and XPS analyses in this work. The patterned Zn, Fe and Ti films were deposited on the Si wafer surface by thermal evaporation and changes in the surface morphology after dry cleaning with $Cl_2$and UV/$Cl_2$at $200^{\circ}C$ were studied by optical microscopy and SEM. In addition, changes in the surface roughness of Si wafer with the cleaning was observed by AFM. The chemical bonding states of the Zn, Fe and Ti deposited silicon surface were observed with in-line XPS analysis. Zn and Fe were easily cleaned in the form of volatile zinc-chloride and iron-chloride as verified by the surface morphology changes. Ti which forms involatile oxides was not easily removed at room temperature but was slightly removed by UV/$Cl_2$at elevated temperature of $200^{\circ}C$. It was also found that the surface roughness of the Si wafer increased after $Cl_2$and UV/$Cl_2$cleaning. Therefore, the metallic contaminants on the Si wafer can be easily removed at lower temperature without surface damage by a continuous process using wet cleaning followed by UV/$Cl_2$dry cleaning.

• Korean Journal of Food Science and Technology
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• v.39 no.4
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• pp.452-457
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• 2007

In this study, Lilium sp. were separated into bulbs, leaves, and flowers. Then, total polyphenol contents, electron donating ability (EDA), superoxide dismutase (SOD)-like activity, hydroxyl radical scavenging activity, and antimicrobial activity were measured from the extracts of each of the three aforementioned parts. The examination of physiologically active substances in the three parts revealed that Lilium davidii leaves had high total polyphenol contents, SOD-like activity, hydroxyl radical scavenging activity, and EDA, while the flowers of L. lancifolium showed high SOD-like activity, hydroxyl radical scavenging activity, and EDA, as well as a high level of total polyphenols in the bulb. Measurements of the antimicrobial activities of the extracts against Gram positive bacteria revealed that the leaves and flowers of L. davidii and L. lancifolium caused Bacillus subtilis and Salmonella enteritidis to form clear zones greater than 10 mm. Furthermore, the flowers of L. lancifolium showed particularly high antimicrobial activity against B. subtilis, and the flowers of L. davidii had high activity against S. enteritidis. For the Gram negative bacteria, the leaves and flowers of L. davidii and L. lancifolium caused Listeria monocytogenes and Escherichia coli to form clear zones greater than 10 mm, and finally, the flowers of L. davidii and L. lancifolium showed high antibacterial activity, with inhibition exceeding 12 mm.

• Cross-Cultural Studies
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• v.36
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• pp.37-59
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• 2014

William Wordsworth's "The Thorn" revolves around the following questions: Who is Martha? Why does she go to the mountain top and repeat her doleful cry? To these questions, it gives us two different kinds of answers; one derives from the villagers, and the other from the narrator. This essay attempts to examine how the answers exemplify two different critical approaches to the problem of community, using Jacques Lacan's account of sexual difference in his seminar on Encore as a guiding thread of analysis. The important thing to retain here is that sexual difference in Lacan's seminar on Encore does not so much indicate biological determinations as two distinct forms of relating to the other which are intimately bound up with the question of how a community is constructed and maintained. The first form, called "masculine," suggests that it is a radical exception to a community that makes possible the community as a field of totality or sameness; the second form, called "feminine," shows that each of the subjects cannot be regarded as a member of a closed community which is guaranteed by the exceptionality, but as an exception that is radically singular. This in turn leads us to consider the possibility that the masculine form has to do with the villagers' effort to distinguish themselves from Martha and the feminine form with the way in which the narrator confronts and represents her. In the course of his formulation of sexuation graph, Lacan stresses that the masculine side must be supplemented by the feminine side, which allows us to elaborate on why, concerning Martha, the narrator does not just keep the completely different position from the villagers'. This is to say that the villagers' representation of Martha as an exception to the community should be supplemented by the narrator's attempt to tell Martha's story as the villagers do and at the same time to capture something of her enigmatic unrepresentability. Bearing in mind Charles Shepherdson's elaboration of traumatic memory, this essay also tries to clarify how the narrator preserves and even transmits something of Martha's truth that is embodied in her uncontrollable and unassimilable cry.