• Textile Coloration and Finishing
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• v.20 no.1
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• pp.1-7
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• 2008

The study has attempted to introduce a new coating than the conventional standardized method of spray, padding and roll coating. The study has focused on finding condition for separating water and organic layer in marble bath and surface effects according to kind of raw hide. It was found that dyestuff-free was to be used in water layer and the input amount of initial insoluble pigment to be added in marble bath should be adjusted following the change of surface area of the marble bath in order to get efficient marble effect while preventing coagulation of water and organic layers. Eventually, amorphous high value-added leather could be obtained treated in process other than the conventional standardized method. Even raw hides of low grades($C{\sim}E$ grades) could be processed into amorphous marble effect that could conceal or shield surface scratches by the colorant, which eventually eliminated necessity of using excessive amount of chemicals in the coating process leading to achieving high quality marble leather of natural look.

• Korean Journal of Heritage: History & Science
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• v.56 no.2
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• pp.148-169
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• 2023

Hayeob pigment is known as one of the traditional dark green pigments, but the color, raw material, and manufacturing method have not been clearly identified. However, comparing the analysis results of the particle shape and constituent minerals of Hayeob pigments revealed through pigment analysis studies of colored cultural properties such as Dancheong, Gwaebul, and paintings, Hayeob pigments appear to be the same as Dongrok pigments produced by salt corrosion. Therefore, in order to restore Hayeob pigment, the manufacturing method of Dongrok pigment was studied based on the records of old literature. The Dongrok pigment manufacturing method confirmed in the old literature records is a natural corrosion method in which copper powder and a caustic are mixed and then left in a humid condition to corrode. Based on this, artificial corrosion using a corrosion tester was adopted to corrode the copper powder more efficiently, and an appropriate mixing ratio was selected by analyzing the state of corrosion products according to the mixing ratio of the caustic agent. In addition, the manufacturing method of Dongrok pigment was established by adding a salt removal process to remove residual caustic agents and a purification process to increase chroma during pigment coloring. The prepared Dongrok pigments have a bluish green or green color, show an elliptical particle shape and a form in which small particles are aggregated, and a porous surface is observed. The main constituent elements are copper(Cu) and chlorine(Cl), and the main constituent mineral is identified as atacamite [Cu₂Cl(OH)₃]. As a result of an accelerated weathering test to evaluate the stability of the prepared Dongrok pigments, it was found that the greenness partially decreased and the yellowness significantly increased as deterioration progressed. Before deterioration, the Dongrok pigments had lower yellowness compared to the Hayeob pigments of the old Dancheong, but after deterioration, yellowness increased significantly, and it was found to have a similar chromaticity range as Dancheong's Hayeob pigments. As a result, the prepared Dongrok pigments were confirmed to be similar to Dancheong's Hayeob pigments in terms of color as well as particle shape and constituent minerals.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.23 no.3
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• pp.86-91
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• 1997

Some natural polyhydroxy aromatic compounds have inhibitory activity against tyrosinase, key enzyme for formation of melanin pigment. We examined the structure-activity relationship of the natural polyhydrowy aromatic compounds and synthesized a number of new derivetives through various methods. Skin lightening effects of these compounds were examined through inhibition of mushroom tyrosinase and inhibitory of melanogenesis on B-16 melanoma cells. These new compounds showed strong inhibitory activity against tyrosinase. Good lightening effects sue to inhibition of melanogenesis were observed from several resorcinol and pyrogallol derivatives. In toxicological tests such as skin primary irritation and sensitization, the above compounds were sufficiently safe for cosmetic use.

• Preventive Nutrition and Food Science
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• v.12 no.3
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• pp.135-140
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• 2007

Antibacterial activities of the major phenolic components from Camellia sinensis L. were investigated against several pathogenic microorganisms including Gram-positive strains like Staphylococcus aureus ATCC 29213 and Streptococcus pyogens 308A; and Gram-negative strains like Escherichia coli ATCC 25922, Escherichia coli 078, Pseudomonas aeruginosa 9027, and Enterobacter cloacae 1321E. The MIC values demonstrate that both (-)-epicatechin and (-)-epigallocatechin were more considerably toxic against Staphylococcus aureus ATCC 29213 than the other two catechins like (-)-epicatechingallate and (-)-epigallocatechin-3-gallate. (-)-Epicatechingallate and (-)-epigallocatechin-3-gallate were most inhibitory against Escherichia coli ATCC 25922. As a result, (-)-epicatechin showed predominant antibacterial activities among tea varieties. The contents of major polyphenolic components such as four catechins, theaflavin, and quercetin were different according to fermentation processes. The total contents of four catechins were ranged from 13.81 to 1.33%, with (-)-epigallocatechin-3-gallate being dominant among tea varieties; theaflavin was found the characteristic pigment in fully-fermented black tea.

• Journal of Microbiology and Biotechnology
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• v.24 no.9
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• pp.1232-1237
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• 2014

Lycopene, which is a well-known red carotenoid pigment, has been drawing scientific interest because of its potential biological functions. The current study reports that lycopene acts as a bactericidal agent by inducing reactive oxygen species (ROS)-mediated DNA damage in Escherichia coli. Lycopene treatment elevated the level of ROS-in particular, hydroxyl radicals ($^*OH$)-which can damage DNA in E. coli. Lycopene-induced DNA damage in bacteria was confirmed and we also observed cell filamentation caused by cell division arrest, an indirect marker of the DNA damage repair system, in lycopene-treated E. coli. Increased RecA expression was observed, indicating activation of the DNA repair system (SOS response). To summarize, lycopene exerts its antibacterial effects by inducing $^*OH$-mediated DNA damage that cannot be ameliorated by the SOS response. Lycopene may be a clinically useful adjuvant for current antimicrobial therapies.

• The Journal of Natural Sciences
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• v.19 no.1
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• pp.27-35
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• 2008

The importance of microbial activity in the alteration and deterioration of stone and concrete walls has been frequently neglected. Organisms present on stone monuments can include photolithoautotrophs, such as algae, cyanobacteria, mosses, and higher plants. Because of their ability to survive repeated drying and rehydration cycles and high UV levels, the cyanobacteria are particularly important on exposed surfaces. The cyanobactria distributed on the surface of the stone cultural heritages in Gwanschoksa, Nonsan city were investigated. Chlorococcus sp. Aanabaena sp. Gloeocapsa sp Lyngbya sp. Stigomena sp. Synechocystis sp were identified. Haplaosiphon fontinalis and Stigonema turfaceum, which were not recoded is Korea, were also identified. Cells often have thick pigmented sheath in dry, sun-exposed environment and shorter filament, which can be different than that in aquatic systems. Special attention should be paid to production of an adequate DNA database in order to accelerate the rate at which information on the species present in biofilms become available.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.3
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• pp.232-239
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• 1994

In order to determine the utilization of ascidian tunic, which has been blamed for problems of costal environmental pollution when discharged into the sea after being used as a natural dietary pigment sources for rainbow trout(Oncorhynchus mykiss), fingerlings were fed on experimental diets containing acetone-extracts for 6 weeks. The amounts of acetone-extracts were 11,000mg/Kg and contained 50mg/100g wet tissues of carotenoid and $6\%$ of carotenoids were astaxanthin. From the results of feeding experiments, the growth rate in the extract group was a little higher than that of the control and pink groups after 6 weeks. The redness and yellowness of the fish skin and muscle in the extract group were similar to the pink group. Therefore, acetone-extracts of ascidian tunic were judged to be a natural dietary pigment source suitable as a substitute synthetic pigment for aquaculture use.

• Journal of Conservation Science
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• v.35 no.6
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• pp.600-611
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• 2019

Yellow to reddish brown soil is generally referred to as hwangto and is used in various industries in Korea. Despite the fact that it is used as an inorganic pigment in dancheong, limited studies have been conducted on the properties of pigments associated with soil and on the mineralogical characteristics of hwangto. This study examines how the pedological and mineralogical features of hwangto affect pigment properties. Results indicate that reddish and yellowish soils have differences in terms of soil texture, mineral composition, oil absorption and stability under light. Reddish soil is mostly found in clay regions, whereas Ulleungdo hwangto is found in loam regions. Yellowish soil is mostly present in the clay loam to loam zones. whereas Haenam hwangto exists in the sandy clay loam zone. As a result of a mineralogical analysis, reddish soil is classified into the feldspar group and clay soil. The major minerals in the yellowish soils are similar however these soils differ in terms of clay mineral compositions. results of the characteristics of pigments prepared by the traditional method revealed that the average particle size is in the range of 10-20 ㎛, reddish soil has an average of 20 ml/100 g higher oil absorption than yellowish soil. In addition, reddish soil is more susceptible to discoloration and deterioration under light than yellowish soil. This study confirms that the soil and mineral characteristics of hwangto affect the physical properties and stability of produced pigments. These result can be used as basic data in future studies natural inorganic pigments using hwangto.

• Journal of Conservation Science
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• v.32 no.3
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• pp.403-416
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• 2016

Mineral composition and content of 22 Korean Dancheong pigment products were obtained by Rietveld quantitative analysis. Jubosa, Hwang, Seokrok, Seokcheong and Hobun consist of pure cinnabar, orpiment, malachite, azurite and calcite (or aragonite), respectively. Whereas Seokganju, Hwangto, Noerok, Lapis lazuli, Baekto and Cockie hobun mainly consist of hematite, goethite, celadonite, lazurite, kaolin mineral and portlandite, respectively. And they all consist of soil minerals (quartz, feldspar, sericite and vermiculite) and filler minerals in the industry field (calcite, gypsum and anhydrite) at a different content. Quantitative XRD proved more useful method to determined exact mineral composition and content than chemical or microscopical data. If this method utilize for specification of natural pigment product, it is considered to be applicable in restoration technology and conservation science field.

• Journal of the Mineralogical Society of Korea
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• v.31 no.1
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• pp.23-32
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• 2018

Noerok ia a green pigment used in Joseon dynasty, and its main usage was for forming foundation layers of Dancheong, the ornamental paintings on the surface of traditional buildings in Korea, such as the Daeung-jeon(main hall) of Bulguk-sa temple. In this research, we investigated the mineralogical characteristic changes of Noerok, a traditional Korean pigment, depending on its firing temperature. The Noerok that we experimented on was mined from Noeseong Mountain, Pohang where it is locally reserved. The major composition mineral is Celadonite, and the main constituent elements are Fe, Si, K and Mg, that refers to the existence of Fe-rich mica. As a result of phased firing experiment from $105^{\circ}C$ to $1000^{\circ}C$, the color was changed from green to pale green, then to brown, and finally to red in order. In the thermal analysis, endothermic reaction induced by the dehydration of crystalline water was confirmed at around $616^{\circ}C$. In the mineralogical change, the crystal surface [($11{\bar{1}}$) and ($02{\bar{1}}$)] of the mineral collapsed at temperatures above $600^{\circ}C$, and iron oxide was formed at $1000^{\circ}C$ or higher. Therefore, it is estimated that the crystallization temperature of Noerok is below $600^{\circ}C$, and it is also considered that it has undergone the alteration phase up to stage I, based on the presence of only a celadonite.