Host–virus protein interactions are critical for intracellular viral propagation. Understanding the interactions between cellular and viral proteins may help us develop new antiviral strategies. Porcine epidemic diarrhea virus (PEDV) is a highly contagious coronavirus that causes severe damage to the global swine industry. Here, we employed co-immunoprecipitation and liquid chromatography-mass spectrometry to characterize 426 unique PEDV nucleocapsid (N) protein-binding proteins in infected Vero cells. A protein–protein interaction network (PPI) was created, and gene ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) database analyses revealed that the PEDV N-bound proteins belong to different cellular pathways, such as nucleic acid binding, ribonucleoprotein complex binding, RNA methyltransferase, and polymerase activities. Interactions of the PEDV N protein with 11 putative proteins: tripartite motif containing 21, DEAD-box RNA helicase 24, G3BP stress granule assembly factor 1, heat shock protein family A member 8, heat shock protein 90 alpha family class B member 1, YTH domain containing 1, nucleolin, Y-box binding protein 1, vimentin, heterogeneous nuclear ribonucleoprotein A2/B1, and karyopherin subunit alpha 1, were further confirmed by in vitro co-immunoprecipitation assay. In summary, studying an interaction network can facilitate the identification of antiviral therapeutic strategies and novel targets for PEDV infection.

Three-dimensional elastic stresses developed in the root fillet of spur gear tooth due to uniform or non-uniform load distribution are analyzed in detail using global-local technique. Results indicate that root stresses distribute always non-uniformly along tooth width, and the maximum critical root stress (CRS) and its position depend on the face width and load distribution form. The maximum CRS is always higher than the corresponding value obtained under plane assumption and the value on the free surface. So, it is dangerous to use the CRSs calculated in practical gear designs. This research provides knowledge of root stresses for engineer to guard against gear failure and to design for increased loading.

A gradientless method for two-dimensional shape optimization is developed based on the magnitude of local relative-stress difference along the design boundary. The design boundary is modeled by using cubic splines, which are determined by a number of control points. The optimal shape of a design boundary with constant stress is achieved iteratively by moving control points consecutively (correspondingly, changing the shape of the design boundary) by an amount depending on the relative-stress difference between two neighboring boundary points. The key feature of the optimization method is that no arbitrary threshold stress is required. The result quality in terms of accuracy and efficiency are tested and discussed with several finite element analysis examples.

Stress singularities exist on the interface endpoint or internal point, consisting of dissimilar linear elastic bonded wedges. The eigenvalue λ is an important parameter to represent the stress singularity on the interface singular point. And smaller eigenvalue represent stronger stress singularities on the interface singular points. The angular function is another parameter to represent stress singularities around singular points. It is known that the eigenvalue is influenced by the Young’s modulus, Poisson’s ratio and interface angles. The Airy stress eigenfunction method has been used to solve the eigenvalue on the bi- and tri-material junctions by verifying the Young’s modulus. And then talk about angular functions around the bi- and tri-material junctions’ singularity point. At last discuss the feasibility of enhancing the interfacial bonding strength in engineering practice.

A shape optimization method for solving elastic contact problems is proposed based on gradient-less idea(a zero order optimization method). It is found that the contact stress on the elastic contact surface can be smoothed and reduced effectively by both changing the contact surface shape and changing the shape of non-contact surface. To avoid mesh distortion that results in undesirable shape, a move stratrgy for nodal movement has been used in the finite element model. Two examples are presented to show the effectiveness of the proposed method in dealing with elastic contact problems.