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( Liangbo Lin ),( Quanhe Qiu ),( Nian Zhou ),( Wen Dong ),( Jieliang Shen ),( Wei Jiang ),( Ji Fang ),( Jie Hao ),( Zhenming Hu ) 생화학분자생물학회 2016 BMB Reports Vol.49 No.3
Bone morphogenetic protein 9 (BMP9) is a potent inducer of osteogenic differentiation of mesenchymal stem cells. The Wnt antagonist Dickkopf-1 (Dkk1) is involved in skeletal development and bone remodeling. Here, we investigated the role of Dkk1 in BMP9-induced osteogenic differentiation of MSCs. We found that overexpression of BMP9 induced Dkk1 expression in a dose-dependent manner, which was reduced by the P38 inhibitor SB203580 but not the ERK inhibitor PD98059. Moreover, Dkk1 dramatically decreased not only BMP9-induced alkaline phosphatase (ALP) activity but also the expression of osteocalcin (OCN) and osteopontin (OPN) and matrix mineralization of C3H10T1/2 cells. Furthermore, exogenous Dkk1 expression inhibited Wnt/β-catenin signaling induced by BMP9. Our findings indicate that Dkk1 negatively regulates BMP9-induced osteogenic differentiation through inhibition of the Wnt/β-catenin pathway and it could be used to optimize the therapeutic use of BMP9 and for bone tissue engineering. [BMB Reports 2016; 49(3): 179-184]
Mahjouri-Samani, Masoud,Liang, Liangbo,Oyedele, Akinola,Kim, Yong-Sung,Tian, Mengkun,Cross, Nicholas,Wang, Kai,Lin, Ming-Wei,Boulesbaa, Abdelaziz,Rouleau, Christopher M.,Puretzky, Alexander A.,Xiao, K American Chemical Society 2016 Nano letters Vol.16 No.8
<P>Defect engineering has been a critical step in controlling the transport characteristics of electronic devices, and the ability to create, tune, and annihilate defects is essential to enable the range of next-generation devices. Whereas defect formation has been well-demonstrated in three-dimensional semiconductors, similar exploration of the heterogeneity in atomically thin two-dimensional semiconductors and the link between their atomic structures, defects, and properties has not yet been extensively studied. Here, we demonstrate the growth of MoSe2-x single crystals with selenium (Se) vacancies far beyond intrinsic levels, up to similar to 20%, that exhibit a remarkable transition in electrical transport properties from n- to p-type character with increasing Se vacancy concentration. A new defect-activated phonon band at similar to 250 cm(-1) appears, and the A(1g) Raman characteristic mode at 240 cm(-1) softens toward similar to 230 cm(-1) which serves as a fingerprint of vacancy concentration in the crystals. We show that post-selenization using pulsed laser evaporated Se atoms can repair Se-vacant sites to nearly recover the (p)roperties of the pristine crystals. First-principles calculations reveal the underlying mechanisms for the corresponding vacancy induced electrical and optical transitions.</P>
Zhibing Chang,Mo Chu,Chao Zhang,Shuxia Bai,Hao Lin,Liangbo Ma 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.12
Thermal bitumen is an important intermediate derived from kerogen decomposition during oil shale pyrolysis. In this study, free bitumen (FB) and bound bitumen (BB) were obtained by extracting oil shale chars (300- 550 oC) before and after demineralization, and then analyzed by liquid chromatography fractionation, Fourier transform infrared spectroscopy, and gas chromatography/mass spectrometry. The FB yield first increased and then decreased with increasing temperature, and the maximum value was 2.10% at 400 oC. The decarboxylation of acids and decomposition of esters at 350-450 oC decreased the content of these compounds. Meanwhile, the intense cracking reactions of aliphatic compounds and alkyl chains at 400-450 oC decreased the carbon chain lengths and molecular weights of these compounds. From the analytical results obtained for the BB fractions, we suggest that some carboxylic acids or carboxyl group-containing compounds may be trapped on carbonate particles by the formation of Ca2+COO− bonds, whereas other oxygenated compounds (e.g., esters and phenols) can be adsorbed preferentially by clay minerals through Lewis acid-base interactions.