• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.493-496
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• 1997

We have made disperse diazo black D(DB-D) ultrathin films using Langmur-Blodgett(LB) and vacuum-evaporation technique. Physical and electrical properties of the films were investigated. Solution was made with a concentration of 10$^{-3}$ mol/$\ell$ using chloroform. Moving wall apparatus (NL-LB140 S-MWC) was employed to make the LB films. X,Y and Z-type LB films were manufactured and studied by UV/visible absorbance spectra and morphology of surface using atomic force microscopy. Vacuum-evaporated DB-D think films were made at a pressure of 10$^{-5}$ torrr. The absorption peaks appear at 200 and 40nm in the LB films and vacuum-deposited films. And we have studied photoluminescence spectrum of the DB-D films. Also TGA and DSC properties of the DB-D have been observed and current -voltage characteristics of the DB-D LB films have been measured along the perpendicular direction.

• Korean Journal of Microbiology
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• v.29 no.4
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• pp.238-242
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• 1991

Extracellular laccase secreted from Pleurotus ostreatus was activated by $Cu^{2+}$ and $Cu^{+}$ . The enzyme was strongly inactivated by 8-hydroxyquinoline, potassium cyanide, sodium azide, sodium bisulfite and 2-mercaptoethanol. The two ionogenic groups, which have pKa values of 5.60-5.70 and 6.70-6.85 respectively, were found to relate with the active site of this enzyme. The oxidation reactions were brought about by initial single electron transfer process on the active site. The enzyme was found to be a metalloprotein which had about 3.9 cupric ions per molecule of protein as a prosthetic group. The enzyme showed a strong peak at 605 nm and a weak shoulder at 330 nm in UV-Visible absorption spectrum. Both signals disappeated upon treatment of the enzyme with 4 electron equivalent ascorbate. These results indicate that type I Cu peak and type III Cu shoulder are present in laccase.

• Biomaterials Research
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• v.22 no.4
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• pp.328-336
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• 2018

Background: Biogenic fabrication of silver nanoparticles from naturally occurring biomaterials provides an alternative, eco-friendly and cost-effective means of obtaining nanoparticles. It is a favourite pursuit of all scientists and has gained popularity because it prevents the environment from pollution. Our main objective to take up this project is to fabricate silver nanoparticles from lichen, Usnea longissima and explore their properties. In the present study, we report a benign method of biosynthesis of silver nanoparticles from aqueous-ethanolic extract of Usnea longissima and their characterization by ultraviolet-visible (UV-vis), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) analyses. Silver nanoparticles thus obtained were tested for antimicrobial activity against gram positive bacteria and gram negative bacteria. Results: Formation of silver nanoparticles was confirmed by the appearance of an absorption band at 400 nm in the UV-vis spectrum of the colloidal solution containing both the nanoparticles and U. longissima extract. Poly(ethylene glycol) coated silver nanoparticles showed additional absorption peaks at 424 and 450 nm. FTIR spectrum showed the involvement of amines, usnic acids, phenols, aldehydes and ketones in the reduction of silver ions to silver nanoparticles. Morphological studies showed three types of nanoparticles with an abundance of spherical shaped silver nanoparticles of 9.40-11.23 nm. Their average hydrodynamic diameter is 437.1 nm. Results of in vitro antibacterial activity of silver nanoparticles against Staphylococcus aureus, Streptococcus mutans, Streptococcus pyrogenes, Streptococcus viridans, Corynebacterium xerosis, Corynebacterium diphtheriae (gram positive bacteria) and Escherichia coli, Klebsiella pneuomoniae and Pseudomonas aeruginosa (gram negative bacteria) showed that it was effective against tested bacterial strains. However, S. mutans, C. diphtheriae and P. aeruginosa were resistant to silver nanoparticles. Conclusion: Lichens are rarely exploited for the fabrication of silver nanoparticles. In the present work the lichen acts as reducing as well as capping agent. They can therefore, be used to synthesize metal nanoparticles and their size may be controlled by monitoring the concentration of extract and metal ions. Since they are antibacterial they may be used for the treatment of bacterial infections in man and animal. They can also be used in purification of water, in soaps and medicine. Their sustained release may be achieved by coating them with a suitable polymer. Silver nanoparticles fabricated from edible U. longissima are free from toxic chemicals and therefore they can be safely used in medicine and medical devices. These silver nanoparticles were stable for weeks therefore they can be stored for longer duration of time without decomposition.

• Fashion & Textile Research Journal
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• v.7 no.5
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• pp.547-552
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• 2005

The study has objective in raising value of the gray color as a meaningful color suiting sentiments of modern people by expressing the gray color in various perspective utilizing natural dyes that is natural at the same time having aesthetic color tones. For example, the main ingredient used for coloring black and gray color is the pyrogallol tannin and the gray tone dye can be acquired by combining the tannin with iron. In order to find the suitable condition for processing tannin, UV-Vis part absorption spectrum of Gallapple pyrogallol tannin, dye ability based on temperature and time, reflection rate based on concentration, color changes based on acid treatment and alkali treatment, changes on surface based on concentration or metal mordant condition, and lightfastness were measured. Maximum absorption wavelength (${\lambda}_{max}$) of Gallapple tannin was at around 273 nm, while strong absorption was also observed at below 350 nm. Dye ability of Gallapple tannin is done more easily on silk rather than cellulose fibers such as cotton, while the optimum condition for dyeing was observed to be at $60^{\circ}C$, for 20 minutes. As a result of acid treatment, the color of dye material consist highly of gray tones and showed red tone after the alkali treatment. While it was observed that as dye concentration and metal mordant concentration increased the color changed at counter-clockwise direction on the Y-scale of Munsell's scale of colors. Lightfastness was more on a normal fading. I hope this study opens up possibilities towards presenting gray color expressed from tannin as color with diversity and aesthetic value. In future, comparative study between dye expressed from catechol tannin dye materials will be helpful.

• Fashion & Textile Research Journal
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• v.8 no.3
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• pp.343-348
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• 2006

This study aims to attain gray tone dyed goods by using tannin that is contained in green tea. Tannin is given general name of polyphenol, which has a characteristic that bonds with protein and it is used for food preservative that protects against bacteria, as well as its purpose of black tone dye for silk treatment that has been processed since its early ages. In particular, as tannin reacts with all kinds of metallic mordant and changes to various colors, when tannin acid is combined with iron, it becomes tannin steel and produces gray tone color. Tannin that is contained in green tea is condensed tannins and its structure does not hydrolyze, thus having flavan type structure. In order to find the suitable condition for processing tannin, UV-Vis part absorption spectrum of green tea tannin, dye ability based on temperature and time, reflection rate based on concentration, color changes based on acid treatment and alkali treatment, changes on surface based on concentration or metal mordant condition, and lightfastness were measured. Maximum absorption wavelength (${\lambda}_{max}$) of green tea tannin was at around 273nm, while strong absorption was also observed at below 350 nm. Dye ability of green tea tannin is done more easily on silk rather than cellulose fibers such as cotton, while the optimum condition for dyeing was observed to be at $60^{\circ}C$, for 20 minutes. As a result of acid treatment, the color of dye material consisted highly of gray tones and showed overall gray tone with the combined color of yellow and red after the alkali treatment. While it was observed that as dye concentration and metal mordant concentration increased, the color changed at counter-clockwise direction on the Y-scale of Munsell's scale of colors. Additionally, lightfastness was more on a normal fading.

• Journal of the Korean Applied Science and Technology
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• v.37 no.5
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• pp.1138-1150
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• 2020

In this study, an experiment was conducted to develop a sunscreen with antioxidant effects by simultaneously investigating the antioxidant and UV protection capabilities of various plant extracts. First, to investigate the UV-blocking ability of 33 kinds of plant extracts, the absorbance spectrum between the UV wavelength of 280 to 400 nm was investigated. Arrowroot, graviola, wheat sprout, sangbaek skin, thorn meal, lacquer, etc. 11 species were selected. The total polyphenol content, total flavonoid content, and DPPH radical scavenging activity of the selected plant extracts are measured to examine the degree of antioxidant activity, and from this, it is a plant extract that has excellent UV protection and antioxidant activity at the same time. The species was selected. A gel-shaped cream is prepared by mixing the selected gold, hops, and licorice extracts in a ratio of 1:1:1, and the UV protection effect of this cream is measured when the cultured cells are irradiated with UV rays. Determined by the method. As a result of the study, it was confirmed that the selected mixture of plant extracts complemented each other in terms of ultraviolet absorption ability and increased cell damage protection effect. Through these results, it was confirmed that it was possible to develop a sunscreen with an antioxidant effect if the antioxidant and sunscreen capabilities of various plant extracts were determined at the same time.

• Journal of Oriental Neuropsychiatry
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• v.3 no.1
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• pp.84-90
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• 1992

Solvent and TLC-fractionations of the root of Salvia miltiorrhiza have yielded the results as follows ; Solvent fractions Petr. ether Ether Ethy1 acetate Water Control 100uL 0 0.2 35.1 41.9 43.0 50ul 0.7 3.7 37.2 42.0 TLC-fractionation and the Cytotoxic activity Fractions I II III IV V VI Petr. ehter Control 100uL13.0 7.1 16.8 1.2 30.9 23.2 0.5 48.3 50uL 37.1 26.1 30.0 20.1 45.7 27.2 29.7 Among the solvent fractions the petroleum ehter fraction corresponding to the concentration of 20ug/ml has showed the strongest Cytotoxic activity. (no cell survived) A double dilution of the fraction(10ug/ml) still showed strong activity.(0.2 cells survived) The ether fraction contained strong activity. Of the fraction which have veen obtained by a prcparative silicagel TLC I, II, III & IV were cytotoxic, but V and VI were inactive Howevcr, it is worthwhile to note that no one of these has no strong Cytotoxicity as the pertoleum ether fraction itself. This observation says that the active fractions could be additive or synergic to each other. The most active fraction, IV, was scrached out from the TLC and its UV-spectrum taken. The absorption maxima were 207 and 272 nm, indicating the presence of a flavanone strucuture.

• The Plant Pathology Journal
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• v.18 no.1
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• pp.18-22
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• 2002

Two peptaibol antibiotics, peptavirins A and B, which exhibited strong inhibitory effect against Tobacco mosaic vials (TMV) infection, were isolated from steam-cooked rice culture of Apiocrea sp.14T. The peptavirins were identified as new derivatives of chrysospermins, which are 19-mer and have been reported to be produced in a fungal isolate. The physicochemical properties of the peptavirins were mostly identical with chrysospermins A through D except for the UV absorption spectrum. The peptavirins inhibited the growths of the Grampositive bacteria tested, including the plant pathogenic bacterium, Corynebacterium lilium, and the fungus, Aspergillus niger. Peptavirin A was somewhat cytotoxic to cancer cell lines, especially K562 (leukemia) and UACC 62 (melanoma), whereas peptavirin B only exhibited slight cytotoxicity.

• Microbiology and Biotechnology Letters
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• v.27 no.1
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• pp.41-45
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• 1999

A tentative composition and some properties of biosurfactants, type I and type II, from Pseudomonas sp. SW1 are described. Biosurfactant type I and II are soluble in water, dichloromethane, chloroform, and a mixture of chloroform and methanol, respectively. The UV absorption spectrum of biosurfactants showed three characteristic peaks in the range of 212, 250 and 365nm, respectively. As a result of IR spectroscopy, GC/MS analysis and biochemical analysis, biosurfactant type I was a polymeric biosurfactant containing carbohydrate, lipid and protein. The carbohydrate was characterized as rhamnose. The lipid part consists of $C_{14}-C_{23}$ fatty acid when analyzed by GC/MS. The biosurfactant type II was a rhamnolipid consisting of carbohydrate and lipid.

• Journal of Photoscience
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• v.1 no.1
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• pp.9-14
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• 1994

Exposure of isolated intact mitochondria to near UV to visible light resulted in not only loss of respiration, the most well-documented phenomenon regarding phototoxic effects in the respiring organelles, but also lipid peroxidation of membranes and mitochondrial swelling; these turned out to be O$_2$-dependent and thus prevented by anaerobiosis, enhanced by a partial deuteration of the suspension medium, and suppressed by the presence of a singlet oxygen ($^1O_2$) scavenger. Measurements of the spectral dependence of such detrimental effects of light on mitochondrial structure and function revealed that all the resulting spectra bear a significant resemblance to the action spectrum for photogeneration of $^1O_2$ from mitochondrial membranes, which in turn carries the spectral characteristics of light absorption by mitochondrial Fe-S centers. Futhermore, destructing the Fe-S centers by a mercurial treatment of mitochondria brought about a striking reduction of the light-induced membrane peroxidation and swelling of mitochondria. These results are consistent with the suggestion that the impairment of functional, structural integrity of mitochondria caused by strong irradiation is directly related to the production of $^1O_2$ in mitochondria, photosensitized by the Fe-S centers. This paper also presents kinetic data which indicate that, among various membrane-bound protein systems associated with mitochondrial energy metabolism, the respiratory chain is the primary target for photodamage.