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Thermally-induced shape memory polymer composites (SMPCs) have the capability to self-deploy when stimulated by a specific temperature. As a basic component of deployable truss structure, SMPCs thin-wall circular tubes will undergo complex non-linear deformation and changing thermal boundary conditions during application. This article aims to research the mechanical behavior of thermally-induced SMPCs thin-wall circular tubes in a non-uniform thermal field. Thermal properties of SMPCs including thermal conductivities and coefficients of thermal expansion are tested as fundamental temperature-dependent parameters. A 500 mm-long SMPCs thin-wall tube is conducted in the flattening-folding-cooling-reheating experiments through a specially manufactured loading apparatus. Combining phase transition theory and Fourier heat conduction, a coupling algorithm is proposed to describe the thermo-mechanical behavior of SMPCs, which is implemented by the user subroutines VUMAT by commercial finite element analysis packages ABAQUS. By comparing the results from the simulation of the non-uniform thermal field, the simulation of the uniform thermal field and experiments, the coupling algorithm is verified, and the effect on SMPCs from the non-uniform thermal field is given. [ABSTRACT FROM AUTHOR]

(+)- and (-)-Tedanine [(+)-1 and (-)-1], a pair of new enantiomeric indolone alkaloids, along with nine compounds (2–10) were isolated from the marine sponge Tedania sp. The structures of (+)-1 and (-)-1 including absolute configurations were determined by spectroscopic analysis and quantum chemical calculation. Compounds (+)-1 and (-)-1 were the first examples of indolone alkaloids isolated from this genus. In addition, the cytotoxic and antibacterial activities of these compounds were also evaluated. [ABSTRACT FROM AUTHOR]

AbstractA new steroid, 2a-oxa-2-oxo-5β-hydroxy-3,4-dinor-24-methylcholesta-22E-ene (1), together with 10 known ones (2–11), was isolated from the marine sponge Cliona sp. The structures of these compounds were determined by the spectroscopic methods (UV, IR, MS, and NMR) and X-ray diffraction analysis. Compound 1 was the third example of 3,4-dinorsteroid with a hemiketal at C-5 that was isolated from the natural source. In addition, the antibacterial activities of these compounds were also evaluated. However, none of them exhibited significant inhibition effects. [ABSTRACT FROM AUTHOR]

AbstractMatrix metalloproteinase 9 (MMP9) plays a pivotal role in mammary ductal morphogenesis, angiogenesis and glandular tissue architecture remodeling. However, the molecular mechanism of MMP9 expression in mammary epithelial cells of dairy cows remains unclear. This study aimed to explore the underlying mechanism of MMP9 expression. In this study, to determine whether the PI3K/AKT/mTORC1/NF-κB signalling pathway participates in the regulation of MMP9 expression, we treated mammary epithelial cells with specific pharmacological inhibitors of PI3K (LY294002), mTORC1 (Rapamycin) or NF-κB (Celastrol), respectively. Western blotting results indicated that LY294002, Rapamycin and Celastrol markedly decreased MMP9 expression and P65 nuclear translocation. Furthermore, we found that NF-κB (P65) overexpression resulted in elevated expression of MMP9 protein and activation of MMP9 promoter. In addition, we observed that Celastrol markedly decreases P65-overexpression-induced MMP9 promoter activity. Moreover, the results of the promoter assay indicated that the core regulation sequence for MMP9 promoter activation may be located at −420 ∼ −80 bp downstream from the transcription start site. These observations indicated that the PI3K/AKT/mTORC1 signalling pathway is involved in MMP9 expression by regulating MMP9 promoter activity via NF-κB in the mammary epithelial cells of dairy cows. [ABSTRACT FROM AUTHOR]