• Journal of Life Science
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• v.14 no.3
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• pp.478-483
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• 2004

In a model reaction using lysyl oxidase purified partilally from bovine aorta, effect of L-ascorbic acid AsA on the oxidative reaction of lysine in collagen was investigated. Addition of Ash to the reaction mixture under aerobic conditions resulted in the decrease of enzymatic activity. In order to examine the specificity of AsA in the oxidative reaction of lysine, other reductants including A derivatives instead of AsA were added to the reaction mixture. Thiol such as glutathione had no effect on the activities of lysyl oxidase. on the other hand, it was observed that erythorbic acid, which was a stereoisomer of AsA, had the same inhibitory effect on this oxidative reaction as AsA. Moreover, by the addition of 3,4-dihydroxybenzoate, which was structural analog of AsA, the activities decreased in a similar manner to that of AsA. These results indicate that the regulatory effect of AsA on lysyl oxidase is attributed to characteristics of the structure. From the determination of Ash remained in the reaction mixture, it is shown that AsA concentration remarkably decreased by lysyl oxidase of the reaction mixture. It is hypothesized that endiol groups reduces the enzyme-bound $Cu^{+2}$ required for further progress of the reaction, and suggests that AsA regulates specifically the reduction of $Cu^{+2}$ required to oxidize lysyl oxidase. This findings support that AsA has an important regulatory role on the oxidative reaction of lysine and on changes of collagen cross-links with aging.

• Korean Journal of Digital Imaging in Medicine
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• v.8 no.1
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• pp.51-55
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• 2006

The effects of Asaddition in amorphous selenium(a-Se) films for digital X-ray conversion material have been studied using the moving photocarrier grating(MPG) technique. This method utilizes the moving interference pattern generated by the superposition of the two frequency shifted laser beams for the illumination of the sample. This moving intensity grating induces a short circuit current, j$_{sc}$ in a-Se:As film. The transport parameters of the sample are extracted from the grating-velocity dependent short circuit current induced in the sample along the modulation direction. The electron and hole mobility, and recombination lifetime of a-Se films with arsenic(As) additions have been obtained. We have found an Increase in hole drift mobility and recombination lifetime, especially when 0.3% As is added into a-Se film, whereas electron mobility decreases with As addition due to the defect density. The transport properties for As doped a-Se films obtained by using MPG technique have been compared with X-ray sensitivity for a-Se:As device. The fabricated a-Se(0.3% As) device film exhibited the highest X-ray sensitivity out of 5 samples.

• The Korean Journal of Food And Nutrition
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• v.8 no.3
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• pp.159-164
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• 1995

The test possibility of L-ascorbic acid(AsA) assay by ascorbate oxidase(A.O) solution obtained from cucumber was estimated. The results obtained were summarized as follow. The difference of absorbance before and after oxidation of AsA by A.O solution was proportional to the AsA concentration. Iso- AsA compared to same concentration of AsA was 97% response. Therefore, the 0 specificity on Iso- AsA a was deficient. On the sucrose, glucose, fructose were coexisted from 5 times, 500 times of AsA concentration, none of them were affected by any level of AsA concentration. In the case of EDTA, it was not nearly affected that EDTA was coexisted 50 times of AsA concentration, but EDTA Inhibited considerably from 500 times of AsA concentration. The effect of citric acid on the AsA concentration was not in the same level of AsA, however, it was slightly inhibited from 5 times, 50 times of AsA concentration and 500 times of AsA inhibited remarkably As known L-AsA was catalycally autooxidated by Cu2+ and Fe2+. They were not nearly affected In the above 0.01M level on the Ash assay. However, Fe3+ ion was neither nearly affected in the 0.001M level nor In the above 0.01M level on the AsA assay.

• Journal of English Language & Literature
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• v.64 no.4
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• pp.617-628
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• 2018

The aim of this essay is to discuss the relationship between Korean literature and Korean intellectual scenes. Since its first introduction to the local context, literature as a genre has served as a field in which colonial and post-colonial intellectuals have attempted to win the accreditation of Western enlightenment. Literature has been regarded as a crucial instrument of liberal arts and education in Korea. Literature has functioned as a social movement in Korea since its inception. During the colonial period, radical intellectuals and literary writers published essays and articles in literary journals. This status as a social movement is still a distinctive characteristic of Korean literature. From the outset, Korean literature has functioned as an enlightenment project for cultural development. As such, Korean literature retains a political meaning of "literariness," which reshuffles the hierarchy of the sensible and creates novelty against given aesthetic regimes. As a result, in the process these regimes are thereby de-purified of their status as purely aesthetic movements; their perspectives thereby come into contact with other discourses and practices outside the art world. This essay argues that as a genre, Korean literature always functions as "world literature" in Korean intellectual scenes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.12 no.3
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• pp.284-288
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• 1983

This experiment was carried out to investigate the stability of ascorbic acid (AsA) in the mixed solution of AsA and catechin according to the content changes of AsA and catechin under boiling, and for the respective concentration and pH. The loss of AsA was most for 10 minutes of boiling and accelerated by the mixture of catechin, but the loss was less in the high mixture rate than in the low the loss of catechin most for 10 minutes of boiling, also as the concentration of AsA becomes higher but that of cathchin lower, and as that of AsA lower but that of catechin higher, the loss of catechin becomes less moreover in the case of the low content ratio of catechin, the stability of AsA was better in order of the pH 4, pH 5, pH 6, namely as the pH increased, but in the case of the high better in order of the pH 6, pH 5, pH 4, that is as in decreased.

• Journal of the Korean Society of Costume
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• v.54 no.3
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• pp.13-25
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• 2004

The purpose of this study was to show the analysis system and the expression which is applied to fashion illustration by three major components in visual sign, metaphor and metonymy. The results of this study were as follows : Firstly, metaphor in qualisign of syntactics was revealed as a color such as realistic description, a pattern such as clothing of figure. etc. Metonymy was revealed as a social and cultural background color, a concept pattern. etc. In sinsign of syntactics. metaphor was revealed as a human body, non-human body and metamorphosis human body and metonymy as a human body and non-human body. In legisign of syntactics, the metaphor by perspective was used for a fantasy of space. and the metonymy was revealed as a color perspective representation, etc. The degree of change of texture was revealed as a metaphor and metonymy of gradation. And conventional custom sign was almost revealed in metaphor. Secondly, semantics showed about fashion image as juxtaposition of two similar objects in metaphor and as real description and simplification in metonymy Alternative fashion image in semantics was presented as a object related to fashion image. Conventional symbolic sign was presented as a role to clarify a fashion message in metaphor. Thirdly, the metaphorical and metonymical expression in pragmatics were usually presented as drawing and painting.

• Korean Journal of Materials Research
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• v.14 no.2
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• pp.146-151
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• 2004

We investigated the effects of high potential barriers on the optical characteristics of InAs quantum dots (QDs) by using photoluminescence (PL) and photoreflectance (PR) spectroscopy. A sample with regular InAs quantum dots on GaAs was grown by molecular beam epitaxy (MBE) as a reference. Another InAs QDs sample was embedded in single AlGaAs barriers. On the other hand, a sample with GaAs/AlGaAs superlattice barriers was adopted for comparison with a sample with a single AlGaAs layer. In results, we found that the emission wavelength of QDs was effectively tailored by using high potential barriers. Also, it was found that the optical properties of a sample with QDs embedded in GaAs/AlGaAs superlattices were better than those of a sample with QDs embedded in a single layer of AlGaAs barriers. We believe that GaAs/AlGaAs superlattice could effectively prevent the generation of defects.

• Microbiology and Biotechnology Letters
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• v.24 no.5
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• pp.613-618
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• 1996

Microorganisms capable of producing ascorbic acid-2-phosphate (AsA2P) from ascorbic acid (AsA) and pyrophosphate (PPi) were screened from the culture collection of this laboratory. Among them, Cellulomonas sp. AP-7 showed the highest productivity of AsA2P. The optimal conditions for the production of AsA2P from AsA and PPi with cell-free extract as an enzyme source were investigated. The reaction mixture for the maximal production of AsA2P consisted of 21 g protein of cell-free extract per liter as the enzyme source, 250 mM AsA, 200 mM sodium pyrophosphate, 150 mM sodium acetate buffer (pH 4.5). By using this reaction mixture, 31.9 mM of AsA2P, which corresponded to a 12.76% yield based on AsA, was produced after incubation of 48 hr at 33$\circ$C.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.4
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• pp.582-587
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• 1997

The changes of ascorbic acid(AsA) and dehydroascorbic acid(DHAA) contents in distilled water, carrot juice, and carrot+vegetable juices under different incubation time and temperature were determined by using high performance liquid chromatography. AsA in carrot juice was more stable than that in distilled water. AsA contents in distilled water and carrot juice were gradually reduced in a time and temperature dependent manner. AsA contents in carrot juice and carrot+ vegetable juices stored in refrigerator(4$^{\circ}C$) for 2 and 24 hours appeared to decrease, but the DHAA contents in all samples increased. Total vitamin C(AsA+DHAA) contents in carrot juice and carrot +vegetable juices remained with the high residue values of 90~97% after incubating at 4$^{\circ}C$ for 2 and 24 hours.

• Journal of Microbiology and Biotechnology
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• v.17 no.5
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• pp.769-773
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• 2007

With the aim to produce ascorbic acid-2-phosphate(AsA-2-P) from L-ascorbic acid(AsA, Vitamin C), nine bacteria conferring the ability to transform AsA to AsA-2-P were isolated from soil samples alongside known strains from culture collections. Most isolates were classified to the genus Brevundimonas by 16S phylogenetic analysis. Among them, Brevundimonas diminuta KACC 10306 was selected as the experimental strain because of its the highest productivity of AsA-2-P. The optimum set of conditions for the AsA-2-P production from AsA using resting cells as the source of the enzyme was also investigated. The optimum cultivation time was 16 h and the cell concentration was 120g/l(wet weight). The optimum concentrations of AsA and pyrophosphate were 550mM and 450mM, respectively. The most effective buffer was 50mM sodium formate. The optimum pH was 4.5 and temperature was $40^{\circ}C$. Under the above conditions, 27.5g/l of AsA-2-P was produced from AsA after 36 h of incubation, which corresponded to a 19.7% conversion efficiency based on the initial concentration of AsA.