Nonconstant positive steady states and pattern formation of a diffusive epidemic model

It is our purpose in this paper to make a detailed description for the structure of the set of the nonconstant steady states for the two-dimensional epidemic S-I model with diffusion incorporating demographic and epidemiological processes with zeroflux boundary conditions. We first study the conditions of diffusion-driven instability occurrence, which induces spatial inhomogeneous patterns. The results will extend to the derivative of prey’s functional response with prey is positive. Moreover, we establish the local and global structure of nonconstant positive steady state solutions. A priori estimates for steady state solutions will play a key role in the proof. Our results indicate that the diffusion has a great influence on the spread of the epidemic and extend well the finding of spatiotemporal dynamics in the epidemic model

Deformation mechanisms in nanotwinned metal nanopillars

Nanotwinned metals are attractive in many applications because they simultaneously demonstrate high strength and high ductility, characteristics that are usually thought to be mutually exclusive. However, most nanotwinned metals are produced in polycrystalline forms and therefore contain randomly oriented twin and grain boundaries making it difficult to determine the origins of their useful mechanical properties. Here, we report the fabrication of arrays of vertically aligned copper nanopillars that contain a very high density of periodic twin boundaries and no grain boundaries or other microstructural features. We use tension experiments, transmission electron microscopy and atomistic simulations to investigate the influence of diameter, twin-boundary spacing and twin-boundary orientation on the mechanical responses of individual nanopillars. We observe a brittle-to-ductile transition in samples with orthogonally oriented twin boundaries as the twin-boundary spacing decreases below a critical value (~3–4 nm for copper). We also find that nanopillars with slanted twin boundaries deform via shear offsets and significant detwinning. The ability to decouple nanotwins from other microstructural features should lead to an improved understanding of the mechanical properties of nanotwinned metals

miRNA-16-5p inhibits the apoptosis of high glucose-induced pancreatic β cells via targeting of CXCL10: potential biomarkers in type 1 diabetes mellitus

Introduction: We aimed to elucidate the relationship between CXC chemokine ligand 10 (CXCL10) and miR-16-5p, and their functions on the biological behaviour of type 1 diabetes mellitus (T1DM). Material and methods: The GSE72492 dataset from the GEO database was used to analyse gene expression. We discovered that CXCL10 was highly expressed in T1DM patients. The up-stream miRNA was predicted by Targetscan website. Low glucose (2.8 mmol/L) and high glucose (HG, 16.7 mmol/L) were utilised to treat β-TC-tet (pancreatic β cell) cells to form the model. The direct interaction between miR-16-5p and CXCL10 was verified by a dual-luciferase reporter assay. Real-time quantitative PCR (qRT-PCR) and western blotting analyses were used to detect RNA and protein expression. CCK8 and flow cytometry were used to detect cell proliferation and apoptosis. Results: We discovered that CXCL10 was highly expressed in T1DM patients. MiR-16-5p, which was lowly expressed in T1DM patients, was verified the upstream regulatory miRNA of CXCL10. The facilitating influence of miR-16-5p up-regulation on the proliferation of HG-induced β-TC-tet cells was reversed by CXCL10 over-expression, while the knockdown results were opposite. More importantly, the restraining impact of miR-16-5p high expression on the apoptosis of HG-induced β-TC-tet cells was accelerated by CXCL10 over-expression. Correspondingly, the level of Bcl-2 was enhanced while the levels of Bax and Cleaved Caspase-3 were lowered by miR-16-5p mimic, which were reversed by CXCL10 over-expression in HG-treated β-TC-tet cells. Conclusions: Our data offered evidence that miR-16-5p implicated in T1DM cell proliferation and apoptosis through targeting CXCL10, which might provide novel therapeutic information for T1DM.

Newly recognized mosquito-associated viruses in mainland China, in the last two decades

There are four principal arboviruses in mainland China. Two kinds of them are mosquito-borne viruses, namely Japanese encephalitis virus and dengue virus, which lead to Japanese encephalitis, and dengue fever/dengue hemorrhagic fever respectively; the other two are tick-borne viruses, namely tick-borne encephalitis virus and Crimean-Congo hemorrhagic fever virus (also known as Xinjiang hemorrhagic fever virus), which contribute to tick-borne encephalitis and Xinjiang hemorrhagic fever respectively. With exception of these four main arboviruses, many other mosquito-associated viruses have been isolated and identified in recent years. These newly isolated and identified mosquito-associated viruses are probably responsible for human and animal infections and diseases. The purpose of this review is to describe the newly isolated mosquito-associated viruses in mainland China which belong to five viral families, including their virological properties, phylogenetic relationships, serological evidence, as well as to appeal the public health concentration worldwide

Defects controlled wrinkling and topological design in graphene

Because of its atomic scale thickness, the deformation energy in a free standing graphene sheet can be easily released through out-of-plane wrinkles which, if controllable, may be used to tune the electrical and mechanical properties of graphene. Here we adopt a generalized von Karman equation for a flexible solid membrane to describe graphene wrinkling induced by a prescribed distribution of topological defects such as disclinations (heptagons or pentagons) and dislocations (heptagon–pentagon dipoles). In this framework, a given distribution of topological defects in a graphene sheet is represented as an eigenstrain field which is determined from a Poisson equation and can be conveniently implemented in finite element method simulations. Comparison with atomistic simulations indicates that the proposed model, with only three parameters (i.e., bond length, stretching modulus, and bending stiffness), is capable of accurately predicting the atomic scale wrinkles near disclination/dislocation cores while also capturing the large-scale graphene configurations under specific defect distributions such as those leading to a sinusoidal surface ruga or a catenoid funnel

The Neglected Arboviral Infections in Mainland China

The major arboviral diseases in mainland China include Japanese encephalitis, dengue fever, Crimean-Congo hemorrhagic fever (also known as Xinjiang hemorrhagic fever), and tick-borne encephalitis. These and other newly found arbovirus infections due to Banna virus and Tahyna virus contribute to a large and relatively neglected disease burden in China. Here we briefly review the literature regarding these arboviral infections in mainland China with emphasis on their epidemiology, primary vectors, phylogenetic associations, and the prevention programs associated with these agents in China

Factors responsible for the emergence of arboviruses; strategies, challenges and limitations for their control

International audienceSlave trading of Africans to the Americas, during the 16th to the 19th century was responsible for the first recorded emergence in the New World of two arthropod-borne viruses (arboviruses), yellow fever virus and dengue virus. Many other arboviruses have since emerged from their sylvatic reservoirs and dispersed globally due to evolving factors that include anthropological behaviour, commercial transportation and land-remediation. Here, we outline some characteristics of these highly divergent arboviruses, including the variety of life cycles they have developed and the mechanisms by which they have adapted to evolving changes in habitat and host availability. We cite recent examples of virus emergence that exemplify how arboviruses have exploited the consequences of the modern human lifestyle. Using our current understanding of these viruses, we also attempt to demonstrate some of the limitations encountered in developing control strategies to reduce the impact of future emerging arbovirus diseases. Finally, we present recommendations for development by an international panel of experts reporting directly to World Health Organization, with the intention of providing internationally acceptable guidelines for improving emerging arbovirus disease control strategies. Success in these aims should alleviate the suffering and costs encountered during recent decades when arboviruses have emerged from their sylvatic environment