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The nanostructured WC–23Co particles were deposited on three kinds of substrates in different accelerating gas temperature by using cold spraying process. The morphologies of nanostructured WC–23Co splats attached on the polished surface of different substrates were characterized via scanning electron microscopy. It is revealed that the splats are partially embedded in Q235 and stainless steel with a comparative integrated contour similar to that of the original particles. There exist some revers around the splats and some corrugations or ripples on the Q235 and stainless steel substrates. In contrast, the splats on the surface of WC–12Co substrate present clearly a flat shape with central hump surrounded by a ringy band. By comparison of the morphologies of splats deposited on three kinds of substrates with the accelerating gas temperature of 850 ± 10°C and 750 ± 10°C, it can be found that the deformation of nanostructured WC–23Co particles is enhanced by the increment of substrate hardness and gas temperature. [ABSTRACT FROM PUBLISHER]

In this paper, a simple, one-step chemical synthesis of Au@poly(m-phenylenediamine) (PMPD) core-shell nanoparticles by direct dropping aqueous chloroauric acid aqueous solution tom-phenylenediamine aqueous solution was reported, which is a facile and green method. We further evaluate the use of the obtained Au@PMPD to modify glassy carbon electrode and for H2O2electrocatalytic biosensing. The results indicate that the aggregated small Au nanoparticles in the inner part of PMPD could be an ideal sensing platform for H2O2detection. [ABSTRACT FROM AUTHOR]

Intervertebral disc degeneration is a common orthopedic disease that has been recognized as the major cause of low back pain. About 80% of the population is affected by this disease. We explored molecular mechanisms of disc degeneration and identified the genes associated with the disease. The transcription profile of GSE34095 was downloaded from Gene Expression Omnibus database with three degenerative disc samples and three healthy disc samples. Gene ontology and pathway enrichment analysis were performed. We constructed a protein-protein interaction (PPI) network and a transcription factor (TF) target network. Differentially expressed genes (DEGs) in normal and disc degeneration samples were identified including 243 up-regulated genes and 351 down-regulated genes. Meanwhile, seven Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were obtained by mapping the 594 DEGs to the KEGG and we found that the calcium signaling pathway was the most significant for developing disc degeneration. The pathways interaction network analysis showed that the adherens junction pathway interacted with other six pathways. In addition, the top five genes, FYN, PRKCD, YWHAB, YWHAZ and AR, with a high degree of interaction of 7, 4, 4, 4 and 4, respectively, were related to the disc degeneration in the PPI network. Furthermore, transcription factors including TFAP2A, E2F4, SP3 and AR had the potential to regulate disc degeneration through the mitogen-activated protein kinase, vascular endothelial growth factor and p53 pathways. The genes and pathways that we identified may be involved in disc degeneration. [ABSTRACT FROM AUTHOR]

In a single degree-of-freedom weakly non-linear oscillator subjected to a periodic external excitation, a small-amplitude excitation may produce relatively large-amplitude vibrations under primary resonance conditions, when the forcing frequency is in the neighbourhood of the linearised natural frequency of the non-linear oscillator. Jump and hysteresis phenomena that result from saddle-node bifurcations may occur in the steady-state forced response. A non-linear vibration absorber is thus used to suppress the primary resonance vibrations. The two linearised natural frequencies of the resultant system formed by the non-linear primary system and nonlinear absorber are not under any internal resonance conditions. The method of multiple scales is used to obtain the averaged equations that determine the amplitudes and phases of the first-order approximate solutions. Illustrative examples are given to show the effectiveness of the non-linear vibration absorber for suppressing non-linear vibrations of the forced oscillator under primary resonance conditions. [ABSTRACT FROM AUTHOR]

In this paper, a cold standby repairable system consisting of two identical components and one repairman is studied. Assume that each component after repair is not “as good as new”, by using a geometric process, we consider two kinds of repair replacement policy, one based on the working age T of component 1 under which the system is replaced when the working age of component 1 reaches T , and the other based on the failure number N of component 1 under which the system is replaced when the failure number of component 1 reaches N . Our problem is to choose optimal replacement policies T * and N * respectively such that the long-run average cost per unit time of the system is minimized. And we can prove under some mild conditions that the optimal policy N * is better than the optimal policy T *. Finally, a numerical example for policy N is given. [ABSTRACT FROM AUTHOR]