• Title/Summary/Keyword: UV stability

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Effects of γ-Irradiation on Antioxidant and Physicochemical Properties of Ishige okamurai Extracts (패 추출물의 항산화능 및 이화학적 특성에 미치는 감마선 조사의 영향)

  • Kim, Mi-Jung;Song, Eu-Jin;Lee, So-Young;Kim, Koth-Bong-Woo-Ri;Kim, Seo-Jin;Lee, So-Jeong;Yoon, So-Young;Kim, Ah-Ram;Jeon, You-Jin;Park, Jin-Gyu;Choi, Jong-Il;Lee, Ju-Woon;Byun, Myung-Woo;Ahn, Dong-Hyun
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.37 no.11
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    • pp.1485-1490
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    • 2008
  • The effects of $\gamma$-irradiation on antioxidant and physicochemical properties of powder and 70% fermented ethanol extracts of Ishige okamurai (I. okamurai) were investigated. In case of powder, although yields were increased, there were no significant changes in total phenolic compounds (TPC) and 2,2-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging effect by $\gamma$-irradiation at 3, 7, and 20 kGy. In case of 70% fermented ethanol extracts, the results of TPC and DPPH radical scavenging effects showed no significant changes. However, antioxidant index increased in the 20 kGy irradiated I. okamurai extracts and decreased in 3 kGy irradiated ones. The optical density value of UV spectrum at 427 nm significantly decreased depending on increasing irradiation dosage. In conclusion, irradiated extracts of I. okamurai can be applied to the food industry due to irradiation stability on antioxidant properties. Also, irradiated extracts can be more useful for food processing as a result of a decrease of extracts color by irradiation.

Spectrophotometric Determination of Soil Chemical Properties Using Soiltek® KA-P Spectrophotometer (Soiltek KA-P 분광광도계률 사용한 토양 화학적 성질의 분광학적 분석)

  • Hyun, Hae-Nam;Oh, Sang-Sil;Koo, Bon-Jun;Kang, Ho-Jun
    • Korean Journal of Soil Science and Fertilizer
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    • v.33 no.2
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    • pp.127-138
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    • 2000
  • To enable rapid and convenient soil test, new soil analytical methods, which require only one instrument, UV/Vis spectrophotometer, were developed and named "Soiltek KA-P spectrophotometric methods". The Soiltek$^{(R)}$ KA-P spectrophotometric method was compared with standard method of RDA in analytical capability for soil chemical properties. Using the 78 soils collected from upland, paddy, orchard, and vinyl house soils, soil organic matter, exchangeable K, Ca, and Mg. CEC, available $SiO_2$, and nitrate were analyzed by the two methods. The color stability(ratio of the absorbance at elapsed time t to the absorbance at time t=0) of organic matter. Ca, Mg, and available $SiO_2$ decreased to about 2% within one hour. However, that of exchangeable K, CEC, and nitrate remained constant. The results obtained with Soiltek$^{(R)}$ KA-P spectrophotometric method showed highly significant correlation with those measured by the standard method of RDA($R^2$ >0.9501), in which the slopes were near unity of $1.0{\pm}0.05$. The standard deviation values of organic matter, exchangeable K, Ca, and Mg, CEC, available $SiO_2$, and nitrate were apparently lower than ${\pm}1.8gkg^{-1}$, ${\pm}0.05cmol^+kg^{-1}$, ${\pm}0.18cmol^+kg^{-1}$, and ${\pm}0.13cmol^+kg^{-1}$, ${\pm}1.0cmol^+kg^{-1}$, ${\pm}5.0mgkg^{-1}$, and ${\pm}10.0mgkg^{-1}$, respectively. All the measurements showed coefficients of variation of less than 7~17% and were within the confidence level of 95%, which means both the methods are precise. Considering the relative simplicity, low cost, precision and accuracy, the proposed Soiltek$^{(R)}$ KA-P spectrophotometric methods could be recommended as an alternative to standard method.

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Development of Water-Resistant O/W Emulsion-Typed Sunscreening Cosmetics through Triblock Polymeric Surfactant-Mediated Re-emulsification Inhibition (삼중블록 고분자 계면활성제의 재유화 억제 기능을 이용한 지속내수성 O/W 에멀젼형 자외선 차단용 화장품 개발)

  • Lee, Ji Hyun;Hong, Sung Yun;Lee, Jin Yong;An, So Youn;Lee, Hyo Jin;Kim, Sung Yong;Lee, Jun Bae;Kim, Jin Woong;Shin, Kyounghee
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.45 no.2
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    • pp.199-208
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    • 2019
  • This study reports water-resistant oil-in-water (O/W) emulsion-based sunscreening formulations prepared using a poly(ethylene glycol)-poly(${\varepsilon}$-caprolactone)-poly(ethylene glycol) (PEG-PCL-PEG) triblock polymeric surfactant. As a result of a variety of outdoor recreational activities such as swimming and hiking, consumer needs for development of advanced water-resistant sunscreen formulations are increasing. Water-resistant sunscreens are mostly based on water-in-oil (W/O) emulsions, because they should not be wiped off by water or sweat. However, the W/O emulsion formulations have a disadvantage in that the feeling of use is oily and difficult to remove. On the other hand, the O/W emulsion formulations are excellent in achieving the better skin feel as well as the easier removal. However, it is difficult to provide the O/W emulsion formulations with the water-repelling performance, since re-emulsification likely occurs upon getting touch with water. To solve this problem, this study proposes a O/W emulsion-based sunscreen formulation, a triblock polymeric surfactant having relatively high interfacial tension HLB value (~ 10). This allows the sunscreen formulations to exhibit the improved water repellence function by preventing their re-emulsification. The sunscreen formation system prepared in this study would be useful for diversification of functional sunscreen products, taking advantages of its excellent emulsion stability, UV protection performance, long lasting water-resistant function and selective cleansing effect with only foam cleanser.

Dismantling and Restoration of the Celadon Stool Treasure with an Openwork Ring Design (보물 청자 투각고리문 의자의 해체 및 복원)

  • KWON, Ohyoung;LEE, Sunmyung;LEE, Jangjon;PARK, Younghwan
    • Korean Journal of Heritage: History & Science
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    • v.55 no.2
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    • pp.200-211
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    • 2022
  • The celadon stools with an openwork ring design which consist of four items as one collection were excavated from Gaeseong, Gyeonggi-do Province. The celadon stools were designated and managed as treasures due to their high arthistorical value in the form of demonstrating the excellence of celadon manufacturing techniques and the fanciful lifestyles during the Goryeo Dynasty. However, one of the items, which appeared to have been repaired and restored in the past, suffered a decline in aesthetic value due to the aging of the treatment materials and the lack of skill on the part of the conservator, raising the need for re-treatment as a result of structural instability. An examination of the conservation condition prior to conservation treatment found structural vulnerabilities because physical damage had been artificially inflicted throughout the area that was rendered defective at the time of manufacturing. The bonded surfaces for the cracked areas and detached fragments did not fit, and these areas and fragments had deteriorated because the adhesive trickled down onto the celadon surface or secondary contaminants, such as dust, were on the adhesive surface. The study identified the position, scope, and conditions of the bonded areas at the cracks UV rays and microscopy in order to investigate the condition of repair and restoration. By conducting Fourier-transform infrared spectroscopy(FT-IR) and portable x-ray fluorescence spectroscopy on the materials used for the former conservation treatment, the study confirmed the use of cellulose resins and epoxy resins as adhesives. Furthermore, the analysis revealed the addition of gypsum(CaSO4·2H2O) and bone meal(Ca10 (PO4)6(OH)2) to the adhesive to increase the bonding strength of some of the bonded areas that sustained force. Based on the results of the investigation, the conservation treatment for the artifact would focus on completely dismantling the existing bonded areas and then consolidating vulnerable areas through bonding and restoration. After removing and dismantling the prior adhesive used, the celadon stool was separated into 6 large fragments including the top and bottom, the curved legs, and some of the ring design. After dismantling, the remaining adhesive and contaminants were chemically and physically removed, and a steam cleaner was used to clean the fractured surfaces to increase the bonding efficacy of the re-bonding. The bonding of the artifact involved applying the adhesive differently depending on the bonding area and size. The cyanoacrylate resin Loctite 401 was used on the bonding area that held the positions of the fragments, while the acrylic resin Paraloid B-72 20%(in xylene) was treated on cross sections for reversibility in the areas that provided structural stability before bonding the fragments using the epoxy resin Epo-tek 301-2. For areas that would sustain force, as in the top and bottom, kaolin was added to Epo-tek 301-2 in order to reinforce the bonding strength. For the missing parts of the ring design where a continuous pattern could be assumed, a frame was made using SN-sheets, and the ring design was then modeled and restored by connecting the damaged cross section with Wood epos. Other restoration areas that occurred during bonding were treated by being filled with Wood epos for aesthetic and structural stabilization. Restored and filled areas were color-matched to avoid the feeling of disharmony from differences of texture in case of exhibitions in the future. The investigation and treatment process involving a variety of scientific technology was systematically documented so as to be utilized as basic data for the conservation and maintenance.