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New Enzyme Based Whitening Cosmetics
Zhibek SADYKOVA,Seunghyun HAN,Trang Vu Thien NGUYEN,Heeyeon BAEK,Yong Hwan KIM 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10
Oxidative stress is one of the major reasons for premature skin aging that form as a result of an imbalance where reactive oxygen species (ROS) suppress the body’s natural antioxidant defense mechanisms. These ROS come from both intrinsic and extrinsic sources such as normal metabolism and UV irradiation. Among them, particularly superoxide anion radical is known as a highly reactive, unstable, and toxic chemical that can have detrimental effects on the skin tissue by causing cellular damage coupled with other reactive species. Thus, the incorporation of powerful enzymatic antioxidants such as Superoxide Dismutase (SOD) that converts superoxide radical into less harmful species can be useful in biocosmetics applications. A gene encoding Mn-SOD from disk abalone (Haliotis discus discus) species was cloned, sequenced, and expressed in Escherichia coli BL21 cells and purified using nickel-nitrilotriacetic acid (Ni-NTA) columns. The activity and thermodynamic stability (Tm) of SOD were measured using Xanthine/Xanthine Oxidase coupled system and Differential Scanning Fluorometry (DSF) methods respectively. The melting temperature (Tm) of SOD and produced H₂O₂ as a result of superoxide dismutation yielded in over 80 ℃ and up to 300 µM H₂O₂ in 1h reaction respectively. Furthermore, we are trying to expand our study by coupling SOD as both H₂O₂ supplier and scavenger of toxic superoxide radicals in the skin.
Giant Strain in Lead-free Relaxor/Ferroelectric Piezocomposite Ceramics
Thi Hinh Dinh,Jin-Kyu Kang,Hoang Thien Khoi Nguyen,Trang An Duong,Jae-Shin Lee,Vu Diem Ngoc Tran,Ky Nam Pham 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.68 No.12
The crystal structural, ferroelectric, and electric-field-induced-strain (EFIS) properties of leadfree relaxor/ferroelectric piezocomposites were investigated. The relaxor-matrix phases were mixed with the ferroelectric-seed phases by using a conventional ceramic processing route. The addition of the ferroelectric seed phase dramatically enhanced the EFIS of the relaxor matrix phase at low electric fields. Giant strains of 745 pm/V at 4 kV/mm and 466 pm/V at 3 kV/mm were obtained when the seed contents were 30 wt% and 50 wt%, respectively, which are much higher than those of the relaxor matrix phase without ferroelectric seeds (575 pm/V at 4 kV/mm and 327 pm/V at 3 kV/mm).