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Achieving high strength and ductility for Ti alloys and their composites has been a key objective and also a great challenge for their engineering applications. Herein, we designed TiC/(TC18 + TC4) composites with bionic and heterogeneously lamella structures, achieving an exceptional combination of high strength and ductility. This is attributed to the formation of alternative layers of TC18-coarse grains and TC4-fine grains with TiC precipitated at their interfaces. Plastic incompatibility of these three-phases produces significant hetero-deformation-induced hardening, induced by mutual interactions of heterogeneous grains and TiC precipitates, as well as activation of extensive < c + a > slip groups. An optimal yield strength of ∼ 1168 MPa and a uniform elongation of ∼ 6% have been achieved, which are much higher than those of the TC4 matrix (i.e. ∼919 MPa and ∼2%). This study provides a new strategy for composite designs to overcome the trade-off dilemma for strength-ductility. [ABSTRACT FROM AUTHOR]

Self-diffusion in liquids is not well understood because of the lack of a clear microscopic knowledge on liquids. Here, on basis of an atomic model for liquids that we concluded from crystal melting, possible atomic details of self-diffusion in liquid metals are proposed. Accordingly, the coefficient of self-diffusion is derived for liquid elements, in reasonable agreement with experimental data.

The solvability for a class of abstract two-point boundary value problems derived from optimal control is discussed. By homotopy technique existence and uniqueness results are established under some monotonic conditions. Several examples are given to illustrate the application of the obtained results.

In general, media coverage would not be implemented unless the number of infected cases reaches some critical number. To reflect this feature, we incorporate the media effect and a critical number of infected cases into the disease transmission rate and consider an susceptible-infected-susceptible epidemic model with logistic growth. Our model analysis shows that early media alert and strong media effects are preferable to decrease the numbers of infected cases at endemic equilibria. Furthermore, we noticed that the model may have up to three endemic equilibria and bi-stability can occur in a threshold interval for the critical number. Note that the interval depends on parameters for the focal disease and the media effect. It is possible to roughly estimate the interval for re-emerging diseases in a given region. Therefore, the result could be useful to health policymakers. Global stability is also obtained when the model admits a unique endemic equilibrium. [ABSTRACT FROM AUTHOR]

To investigate the roles of both coupling noises and distributed delays with strong kernels, a novel delayed stochastic two-species facultative mutualism model is established, in where the strong kernels indicate that the maximum influence on the growth rate response at some time is due to population densities at the previous time, and the saturation effect is also incorporated because the facultative capacity of each species is finite and their interspecific mutualism should be upper bounded in real life. We first transfer the two-species stochastic model with strong kernels into an equivalent six-dimensional model through a linear chain technique. Later, sufficient conditions for the extinction exponentially, persistence in the mean, permanent in time average and stationary distribution are respectively obtained. Finally, numerical simulations are supplied to support our theoretical results. Our analytical results show that the coupling noise intensities play an important role in the long-time behaviors while the strong kernels are independent of the above asymptotic properties.

Background: Intracellular pathogen resistance 1 (Ipr1) has been found in macrophages and plays a pivotal role in fighting against Mycobacterium tuberculosis (Mtb) infection. This study is designed to evaluate the effect of Iprl on the expression of macrophage genes related to the anti-infection of Mtb. Design or methods: In the experimental and control groups, the macrophages were infected with Mycobacterium H37Ra, and then the related immune genes between two groups were detected using microarray assay. Real-time quantitative PCR was applied to detect the differences in the expression of three up-regulated genes detected by microarray assay and to verify the reliability of microarray assay., Results: The expression of Iprl up-regulated 11 genes related to macrophage anti-immunity involved TLRs signaling pathway including TLR2 and TLR4, Irak1, Traf7, Ifngr1 and Tnfrsfla. No significant difference was found in terms of the molecular expression involved in regulation of the adaptive immune response, such as IL-1 and IL-12. The results of real-time PCR were consistent with the findings of microarray assay., Conclusions: The expression of Iprl gene probably promotes macrophage activity and enhances the ability of macrophages to fight against Mtb infection. The underlying mechanism may be achieved by up-regulating the expression levels of innate immunity genes, especially TLR2/TLR4 and signal transduction molecules, which is determined using microarray assay. All these findings offer the basis for subsequent study of the mechanisms of Ipr1 gene in host innate immunity against Mtb infection.