증기폭쇄 방법으로 국내산 대나무줄기에서 추출된 리그닌의 자외선 차단효과

양승화(Seung-Hwa Yang),최문희(Moon-Hee Choi),신현재(Hyun-Jae Shin) 한국생물공학회 2017 KSBB Journal Vol.32 No.4

Bamboo trees have high economic values because of rapid growth rate, rich biomass components and good health effects. Among several parts of bamboo tree, bamboo stem contains a considerable amount of cellulose and lignin, and a little amount of minerals, silica, and etc. In this study, domestic bamboos (Phyllostachys bambusoides (1) and Phyllostachys nigra var. henosis (2)) lignins were prepared by steam explosion (temperature 210oC, 2 MPa) and organosolv pretreatment. The results showed that steam explosion lignin (SEL1, SEL2) had a higher yield (12% and 21%). Characteristics of lignin structures were confirmed by FT-IR, and <SUP>1</SUP>H-, <SUP>13</SUP>C-, and 2D HSQC NMR. SEL1 and SEL2 were the typical GHS-type lignins and their bonds units were predominantly β-O-4’linkages. Antioxidant effects were assayed by DPPH and ABTS radical scavenging activity using ascorbic acid as a standard. The antioxidant activity of SEL1 was the best, and IC50 value of 383.89±25.35 μg/mL and 131.78±0.99 μg/mL, respectively. Cytotoxic concentration levels of all lignin samples were > 100 μg/mL based on MTT assay. To confirm the UV protection effect of lignin, SEL1 was added to commercial sunscreen (SPF 15) and moisturizing cream (no SPF) respectively. Addition of 10 wt% lignin to commercial sunscreen increased 45% of UV absorbance higher than moisturizing cream after 2 h of UV (UVA+UVB) radiation. The result of lignin addition has shown synergistic effects in UV protection and antioxidant effect.

국내산 생달나무 오일 추출물의 지용성 성분 및 항산화 활성 검증

양승화 ( Seung-hwa Yang ),김나인 ( Nain Kim ),주현진 ( Hyun-jin Ju ),최문희 ( Moon-hee Choi ),신현재 ( Hyun-jae Shin ) 조선대학교 공학기술연구원 2021 공학기술논문지 Vol.14 No.3

Cinnamomum yabunikkei H. Ohba is known as a traditional medicinal plant in Korea. There has been no study done about the lipid compound and biological activity in solvent extracts of C. yabunikkei. In this study, the solvent extract (hexane, chloroform:methanol [2:1, v/v]) of C. yabunikkei leaf, branch, and fruit were investigated for their antioxidant activities and active constituents. The antioxidant properties were evaluated based on 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging, ABTS radical scavenging, and lipid peroxidation activity. The branch extract showed the highest DPPH, ABTS, and lipid peroxidation. Antioxidant active substances present in the solvent extract of C. yabunikkei have been analyzed by GC-MS. In summary, C. yabunikkei solvent extracts could be used as a potential natural cosmetic ingredient.

나노입자의 크기효과와 체적분율 효과를 동시 고려한 나노복합재의 멀티스케일 브리징 해석기법에 관한 연구

양승화,유수영,조맹효,Yang, Seung-Hwa,Yu, Su-Young,Cho, Maeng-Hyo 한국전산구조공학회 2009 한국전산구조공학회논문집 Vol.22 No.4

본 연구에서는 분자동역학 전산모사와 미시역학 모델을 이용하여 나노입자의 체적분율이 높은 경우 나노 입자의 크기효과와 체적분율 효과가 나노복합재의 기계적 물성에 미치는 영향을 효과적으로 묘사할 수 있는 순차적 브리징 해석기법을 제안하였다. 체적분율이 12%로 고정된 상태에서 나노입자의 크기변화에 따른 영률과 전단계수를 분자동역학 전산모사를 통해 예측한 후, 이를 연속체 모델에서 구현하기 위해 다중입자모델을 적용하였다. 나노입자의 크기효과를 반영하기 위해 입자와 기지 사이에 유효계면을 추가적인 상으로 도입하였고, 12%의 체적분율 조건에서 나타날 수 있는 체적분율 효과는 나노복합재를 둘러싸는 가상의 영역인 무한영역의 물성값의 변화를 통해 조절되도록 하였다. 유효계면과 무한영역의 물성을 입자의 반경에 대한 함수로 근사한 후 다양한 입자의 크기에서 나타나는 나노복합재의 물성변화의 예측이 가능하도록 하였다. 제안된 브리징 해석기법의 적용을 통해 분자동역학 해석결과와 잘 일치하는 결과를 연속체 모델에서 효율적이고 정확하게 얻을 수 있었다. 또한 유효계면의 두께와 물성 변화가 나노복합재의 기계적 물성에 미치는 영향을 고찰하였다. In this study, an efficient sequential bridging method to characterize both the particle size effect and concentration effect on the mechanical properties of nanocomposites at high volume fraction is suggested through a molecular dynamics(MD) simulations and micromechanics of composites materials. The Young's modulus and the shear modulus of the nanocomposites at various particle radius and at 12% volume fraction were obtained from MD simulations and multi-inclusion model was adopted to describe both modulus in continuum model. In order to describe the particle size effect, an additional phase, effective interface, was adopted as characteristic phase and the non-dilute concentration effect which appears at 12% volume fraction was describe via the variation of the elastic modulus of the infinite medium. Both the elastic modulus of the interface and infinite medium were fitted into functions of particle radius for the applicability of the present bridging method at various particle radii. Using the present bridging method the elastic modulus of the nanocomposites was efficiently obtained with accuracy. In addition, the effect of the interface thickness and modulus on the elastic modulus of the nanocomposite was investigated.

바이오 산업 소재로서의 리그닌

양승화(Seung-Hwa Yang),신현재(Hyun-Jae Shin) 한국생물공학회 2018 KSBB Journal Vol.33 No.4

Lignin, which accounts for 15-35% of the wood components, is being obtained as a by-product in the industrial processes of pulp and in the production of cellulose fuels. It is composed of three main phenyl propane units, p-coumaryl alcohol, coniferyl alcohol, and sinapyl alcohol, which contain a large amount of phenolic hydroxyl groups. In the process of extracting lignin, enzymes and solvents used in each process undergo chemical structural changes during the pretreatment process. Lignin is used in the fields of fine chemicals, polymers, pharmaceuticals and additives, and studies on antioxidant and biological activity are under way. The antioxidative activity of lignin was confirmed by its antioxidant activity, although it depends on the antioxidant activity assay. Several results suggested that lignin should be mixed with conventional antioxidants or synthetic ultraviolet blocking agents rather than using alone. This increases the antioxidant activity and ultraviolet blocking effect by the synergy between lignin and each ingredient. This review described some aspects on a raw material for cosmetics to replace the existing antioxidant raw materials and UV-blocking agents as well as stateof-the-art of lignin research based on literature survey.

국내산 솜대 줄기로부터 추출한 리그닌의 항산화 활성

양승화(Seung-Hwa Yang),최문희(Moon-Hee Choi),신현재(Hyun-Jae Shin) 한국생물공학회 2018 KSBB Journal Vol.33 No.3

Several fractions of lignin were extracted from the stem of domestic bamboo (Phyllostachys nigra var. henosis) through steam explosion and organic solvent fractionation. A maximum yield of 21% and 47% lignin were attained from steam explosion (SL) and non-soluble fraction (SL-F3), respectively. Molecular weights (and poly diversity index) and chemical structure consisting in the lignin were estimated by GPC, FT-IR, and NMR spectrometry. Major carbon-hydrogen bonding has been assigned by HSQC analysis. Among the four fractions, SL-F1 showed the highest polyphenol contents and antioxidant activities (DPPH, ABTS, hydroxyl radical and Fe<SUP>2+</SUP> chelating activities). All four fractions showed no cytotoxicity up to the concentration of 100 ㎍/mL by MTT assay. The lignin fractions would be a valuable asset for many applications including cosmetic products.

나노카본-고분자 복합재의 거시적 거동에 관한 미시적 고찰

조맹효,양승화,Jo, Maeng-Hyo,Yang, Seung-Hwa 한국전산구조공학회 2015 전산구조공학 Vol.28 No.2

국내산 신이대 잎 추출물의 B16F10 흑색종 세포내에서 멜라닌 생성억제

최문희(Moon-Hee Choi),양승화(Seung-Hwa Yang),신현재(Hyun-Jae Shin) 한국생물공학회 2018 KSBB Journal Vol.33 No.1

Bamboo trees have been used as construction material, fiber and food resources. Among many parts of the tree, especially, bamboo leaves are known to contain various bioactive compounds for food and medicinal application. Polyphenols, glycosides, amino acids and minerals such as silica in bamboo leaves have provided antioxidant, astringent, antiwrinkle properties. However, there is little study on the skin whitening effect of the extract. In this study, therefore, inhibition of in-vitro tyrosinase and melanin biosynthesis by the water, ethanol, and methanol extracts of domestic bamboo Sasa coreana Nakai were investigated in B16F10 melanoma cells. The methanol extract (SCM) showed in-vitro tyrosinase inhibition activity with IC50 values of 168 μg/mL, and invivo cytotoxic concentration ranges > 100 μg/mL. Protein expression and transcription levels of TYR, TRP-1, TRP-2 were decreased in a dose-dependent manner by treatment with SCM. These results suggest that SCM could be used as a candidate for a potential whitening agent in cosmetics.

공간 인지 모형을 차용한 디지털 미디어 시스템의 UI 디자인 설계

이수진(Lee Su-Jin),양승화(Yang Seung-Hwa),김진우(Kim Jin-Woo) 한국디자인학회 2009 디자인학연구 Vol.22 No.1

사용자 만족과 감정적 애착의 이론적 통합 모형에 관한 실증적 연구

이인성(In Seong Lee),이기호(Ki Ho Lee),최지웅(Gi Woong Choi),양승화(Seung Hwa Yang),임성택(Seong Taek Lim),전석원(Seok Won Jeon),김진우(Jin Woo Kim),홍세준(Se Joon Hong) 한국경영학회 2008 經營學硏究 Vol.37 No.5

Recently, studies on user experience have become popular within the field of new product development, marketing, and information systems. Most of these studies on user experience hypothesize that user satisfaction is enhanced when users have good experience with a certain device or a system and that enhanced user satisfaction can explain and predict user loyalty effectively. However, since user experience is a broad concept which comprises both the cognitive and the affective elements, whether existing theoretical models of user satisfaction can accurately reflect user experience is questionable. Moreover, it is also not clear whether user satisfaction can effectively explain user loyalty. For example, user`s cognitive appraisal plays a major role in building up user satisfaction with the product; this means that user satisfaction model only focuses on the cognitive aspect of user experience. Thus, the existing theoretical models focusing on user satisfaction cannot reflect the emotional aspect of user experience. Moreover, user satisfaction can be developed even with only a short period of usage; therefore, user satisfaction cannot fully explain the whole aspect of user experience which is developed through the long-term interaction with the product. Moreover, since users who are only satisfied with the product can always move on when there is a better alternative, there is a limitation of maintaining and promoting user loyalty by merely enhancing user satisfaction. This study was conducted to overcome the limitations of such existing theoretical models of user satisfaction by including a new concept known as emotional attachment in order to complement theoretical and practical limitations of the current user satisfaction model. Emotional attachment is an emotional bond between a person and the specific object; this research hypothesizes that the concept of emotional attachment could overcome the limitations of the theoretical model focusing on user satisfaction. Such hypothesis is based on the research results which argue that emotional attachment is formed based on the affective experience through the long-term interaction with a certain object and that the person with emotional attachment toward the object is less likely to be influenced by the existence of more attractive alternatives. In this study, a new theoretical model of emotional attachment based on the perspective of user experience was developed through literature review and was theoretically expanded the user experience model by integrating the emotional attachment and the user satisfaction model. Survey studies have been conducted to empirically validate the theoretically integrated model with users of four digital products (cell phone, MP3 player, TV, and refrigerator). The survey results indicate that our integrated model does indeed explain the relationship between user experience and user Loyalty more faithfully than the existing models. This paper ends with certain limitations as well as implications of the study results.