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This study strategically fabricates a nucleic acid functionalized gold nanoparticle and graphene oxide composite probe (AuNP/GO probe) to achieve both the recognition and in situ monitoring of cytoplasmic target precursor microRNAs (pre-miRNAs) and mature microRNAs (miRNAs) in living cells. The pre-miRNA-21 detection with AuNP probes has a good linear range of 0–300 nM and a limit of detection (LOD) of 4.5 nM, whereas the GO probe has a linear relationship with mature miRNA-21 from 0.1 to 10 nM with a LOD of 1.74 nM. This assay was utilized to directly visualize the relative expression levels of pre- and mature forms of miRNA-21 and let-7a. The results suggested that the expression levels of precursor miRNAs remain constant in cancer cells and normal cells. However, the expression levels of mature miRNAs vary widely, demonstrating the “up-regulation” of miRNA-21 and “down-regulation” of let-7a in cancer cells in contrast to that in normal cells. The practicality of this strategy was verified by in situ monitoring changes in cytoplasmic pre-miRNA-21 and mature miRNA-21 in response to small-molecule inhibitors of miRNA-21.

The tensile fatigue behavior of glass-fiber-reinforced epoxy (GF/epoxy) composites embedded with shape memory alloy (SMA) wires prepared by vacuum assisted resin infusion (VARI) processing was investigated. The experiments were performed under cyclic tensile load. The damage mechanism of SMA composites under different stress levels of cyclic loadings was revealed. The fracture surface and fatigue failure modes of the specimens were examined and analyzed according to the damage mechanism under different stress levels. The stress-number (S-N) curves, the residual strength and residual stiffness of specimens were calculated after the experiment. The results show that the fatigue life of SMA composites is more than twice higher than GF/epoxy composites. Microstructural analysis using the scanning electron microscopy (SEM) technique was conducted on fractured surfaces to fully understand the failure mechanism. The fatigue failure modes in SMA composite laminates were revealed.

The effects of the content and position of SMA wires on the static properties of glass fiber reinforced epoxy (GF/epoxy) composite laminates prepared by vacuum-assisted resin infusion (VARI) process were investigated. According to the influence of different embedding content and position of SMA wire on mechanical performances of composite laminates, the optimal content and optimal position of SMA were found out. The static mechanical finite element models of GF/epoxy composite and shape memory alloy hybrid composites (SMAHCs) are established. The validity of the models is verified by comparing the simulation results with the experimental results. According to the finite element results, the influence of SMA embedding content and position on the mechanical performances of composites is described quantitatively.

The impact response of shape memory alloy hybrid composite (SMAHC) prepared by vacuum-assisted resin infusion was investigated experimentally and numerically. The impact properties of shape memory alloy composites under three impact stages were characterized. A numerical simulation method is used to simulate the impact damage evolution process of SMAHCs. The experimental results are consistent with the numerical results, which further verified the effectiveness of the laminate against impact load after embedding SMA. The impact threshold energy value of impact damage of SMAHCs was found by numerical simulation. The results show that the impact failure of SMAHC laminates requires more energy than GF/epoxy composites due to the excellent energy absorption capacity of SMA.

Five organotin(IV) hydrazone compounds have been synthesized from N’-[(1E)-(2-hydroxyl-3-methoxyphenyl)methylidene]pyridine-3-carbohydrazone and the corresponding organotin(IV). Solid state structures of five complexes were determined by elemental analysis, IR, NMR spectroscopy and for 1, 2, 3, 4 and 5 single crystal X-ray diffraction analysis. For compounds 4 and 5, structural analysis shows that each complex is a monomer with the tin atom five-coordinated in a distorted trigonal bipyramid chelating by the Schiff base ligand in an enolic tridentate fashion. Fascinatingly, in compounds 1, 2 and 3, structural analysis of them shows that each complex is a centrosymmetric trimers, in which the central Sn atom adopts six-coordinated geometry and the other Sn atom adopts five-coordinated geometry. In vitro cytotoxicities of five compounds on three human drug resistant tumor cells lines (A549, HeLa and MCF-7) were assessed by MTT assay. The interaction of the complexes with calf thymus DNA (CT-DNA) has been explored by absorption titration method, which revealed that complexes interact with CT-DNA through groove-binding and partial intercalation of the extended planar ligand with the DNA base stack. Furthermore, the protein fluorescence quenching studies reveal that there are strong binding interactions between compounds and bovine serum albumins (BSA). Studies reveal that di-n-butyltin(IV) complexes 2 and 4 with significant antiproliferative effects in the cells show stronger DNA/BSA interaction than the other complexes.