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Aluminum matrix composites (AMCs) reinforced with intragranular nano-sized Al2O3 were used as model material to investigate the effects of intragranular nano reinforcement on the mechanical properties at macro- and meso- levels. The results revealed that intragranular Al2O3 effectively facilitates the dislocation multiplication, which in turn enables the grain interior to endure high levels of plastic strain and consequently alleviates stress concentration at the grain boundary. Furthermore, intragranular Al2O3 leads to a collective enhancement in the intrinsic mechanical properties across domains of varying sizes, thereby contributing to the coordinated plastic deformation of heterogeneous grains, and enhancing the creep resistance of composite. [ABSTRACT FROM AUTHOR]

Al matrix composites with the strain-delocalization effect were fabricated by spark plasma sintering using graphene nanosheets decorated with Cu nanoparticles (Cu NPs@GNS) as reinforcement. The Joule heat, thermal stress-induced dynamic crystallization and the abnormal grain growth facilitate shorter diffusion paths of Cu atoms in the Al matrix thus generating a supersaturated solid solution near the GNS/Al interface. Thereby, the intragranular plate-like θ ′ -Al2Cu was generated in the adjacent grains of GNS so that the strain-delocalization effect was realized. The combination of excellent strain hardening ability, transgranular fracture mode and elongated crack path results in strength-ductility synergy. Al matrix composites reinforced by graphene nanosheets decorated with Cu nanoparticles fabricated by spark plasma sintering was applied to realize simple and rapid fabrication of composites with strain-delocalization effect. [ABSTRACT FROM AUTHOR]

The microstructure design of graphene based reinforcement is an effective route to obtain graphene/aluminum composites with good mechanical properties. In this study, alumina anchored on graphene nanosheets hybrid (Al2O3@GNS) was in situ synthesized by a sodium chloride template-assisted high-temperature calcination strategy. Al2O3@GNS was used as a reinforcement to fabricate aluminum matrix composites (Al2O3@GNS/Al) by flake powder metallurgy (FPM) route. It was found that Al2O3@GNS was homogenously distributed and a relatively obvious synergistic strengthening effect was acquired by employing Al2O3@GNS as reinforcement of the composites. ∼1.0 vol%-Al2O3@GNS/Al composite obtained the maximum tensile strength of 359 MPa, an ∼131.6% improvement superior to pure Al. The strengthening efficiency of Al2O3@GNS is higher than those reinforced by individual GNS, Al2O3 or its simple mixture. An elongation of 11.2% was achieved in the ∼ 1.0 vol%-Al2O3@GNS/Al composite, exhibiting a favorable strength-ductility synergy. The synergistic strengthening effect was attributed to the formation of an interlocked network of Al2O3@GNS, which was beneficial to improve the load transfer efficiency from the matrix to reinforcement in the composites. [ABSTRACT FROM AUTHOR]

Carbon nanotube (CNT)/metal interface interaction is critical to the mechanical properties of CNT-reinforced metal matrix composites (MMCs). In this paper, in order to realize the chemical modification of the interface interaction between CNTs and Mg matrix, different types of defects (monovacancy, carbon and oxygen adatoms, as well as p-type boron and n-type nitrogen substitution) are introduced in CNTs to investigate the effect of the defects on the interface interaction (Eib) between CNT and Mg (0 0 0 1) surface. Moreover, two models (adsorption model and interface model) are compared and validated to investigate the interface interaction. It is revealed that the CNT with the carbon adatom has the highest Eib with the Mg (0 0 0 1), and the effect of boron doping on Eib is superior to the intermediate oxygen which has already been proved experimentally in the enhancement of the interface interaction in MMCs. In terms of the electronic structure analysis, we reveal the micro-mechanism of the increase of Eib under the action of different types of defects, and propose that the presence of holes (boron dopant) and the unsaturated electrons in CNTs can generate the chemical interaction between CNT and Mg matrix effectively. Our results are of great scientific importance to the realization of robust interfacial bonding between CNTs and Mg matrix via the reinforcement modification, so as to enhance the mechanical properties of CNTs reinforced Mg matrix composites. [ABSTRACT FROM AUTHOR]

Diabetic encephalopathy, which is characterized by cognitive decline and dementia, commonly occurs in patients with long-standing diabetes. Previous studies have suggested that methylglyoxal (MG), an endogenous toxic compound, plays an important role in diabetic complications such as cognitive impairment. MG induces neuronal apoptosis. To clarify whether marein, a major compound from the hypoglycemic plantCoreopsis tinctoria,prevents PC12 cell damage induced by MG, we cultured PC12 cells in the presence of MG and marein. Marein attenuated MG-induced changes in the mitochondrial membrane potential (ΔΨm), mitochondrial permeability transition pores (mPTPs), intracellular Ca2+ levels, the production of reactive oxygen species (ROS), glutathione (GSH)/glutathione disulfide (GSSG) and adenosine triphosphate (ATP), and the increase in the percentage of apoptotic cells. Marein also increased glyoxalase I (Glo1) activity, phospho-AMPKα (Thr172) and Bcl-2 expression and diminished the activation of Bax, caspase-3 and inhibitor of caspase-activated deoxyribonuclease (ICAD). Importantly, pretreatment of cells with marein diminished the compound C-induced inactivation of p-AMPK. Molecular docking simulation showed that marein interacted with the γ subunit of AMPK. In conclusion, we found for the first time that the neuroprotective effect of marein is due to a reduction of damage to mitochondria function and activation of the AMPK signal pathway. These results indicate that marein may be a potent compound for preventing/counteracting diabetic encephalopathy. [ABSTRACT FROM AUTHOR]

Prostate-specific antigen (PSA) test is limited in prostate cancer diagnosis due to its inaccuracy. A new approach which integrates the PSA test with miRNA profiling was investigated to improve prostate cancer diagnosis. Six prostate cancer-related miRNAs (miR-16, -21, -34c, -101, -125b, -141) were tested in five cultured prostate cell lines and 20 human prostate specimens. We found that the miRNA expression profiles were significantly different between nontumorigenic and tumorigenic cell lines and specimens. Positive predictive value analysis of prostate cancer was increased from 40%% to 87.5%% by integrating patient PSA blood levels with miR-21 and miR-141 profiles. [ABSTRACT FROM AUTHOR]