Nonconforming Functions Research Articles

S-adenosylmethionine administration inhibits levodopa-induced vascular endothelial growth factor-A expression.

Background: Studies have demonstrated that S-adenosylmethionine could effectively affect the clinical wearing-off phenomena of levodopa, an antiparkinsonian agent; however, the detailed mechanisms for this effect need to be further clarified.Results: S-adenosylmethionine and levodopa had opposite effects on the protein stability of vascular endothelial growth factor-A. The analysis of tube formation and cell viability also showed the nonconforming functions of S-adenosylmethionine and levodopa on cell angiogenesis and proliferation. Meanwhile, S-adenosylmethionine could significantly abolish the increased angiogenesis and cell viability induced by levodopa. S-adenosylmethionine resulted in G1/S phase arrest, with decreased cyclin dependent kinase 4/6 and increased p16, a specific cyclin dependent kinase inhibitor. Mechanically, the different effects of levodopa and S-adenosylmethionine were dependent on the phosphorylation and activation of extracellular signal-regulated kinase. S-adenosylmethionine could be fitted into the predicted docking pocket in the crystal structure of vascular endothelial growth factor-A, enhancing its acetylation level and reducing half-life.Conclusions: These observations suggested that methyl donor S-adenosylmethionine could act as a potential agent against vascular endothelial growth factor-A-related diseases induced by levodopa treatment.Methods: We performed in vitro cytological analyses to assess whether S-adenosylmethionine intake could influence levodopa-induced vascular endothelial growth factor-A expression in human umbilical vein endothelial cells.

Solid Shell Element Based on Relative Displacement Concept

The relative translational displacement concept can avoid the difficulties when involving the rotational degrees of freedom (DOF) and retain the features associated with the rotational DOF. In this paper, a new solid shell element based on relative displacement is proposed and studied. This new isoparameteric element ensures the C0 continuity between elements. To circumvent the shear-locking phenomenon, The assumed natural strain method is incorporated, and nonconforming shape functions are utilized to improve the performance of the proposed element. Verifications by standard numerical examples show that the performance of this solid shell element is excellent.

Incompatible Bubbles: A non-conforming finite element formulation for linear elasticity

A non-conforming finite element formulation, the Incompatible Bubbles method, is proposed for the problem of linear elasticity. As the classical Incompatible Modes method, the proposed formulation is based on an enrichment of the Galerkin solution space with non-conforming functions, the incompatible bubbles. In fact, the two formulations coincide in the particular case of non-distorted meshes. The advantage of the new formulation is that by a careful choice of the bubbles some of the “variational crimes” of the classical method become unnecessary for convergence, as the analysis reveals. Also, the relationship of the proposed method with more recent subgrid scale finite element formulations is investigated. Numerical examples illustrating the performance of the method are provided.

Boundedness and definiteness qualities of a functional equation for nonconforming trial functions

Abstract A finite element method for a model problem (loaded rod) is based on a variational principle which takes the inter-element discontinuities into account. It is shown by examples that on a special subset of nonconforming trial functions the bilinear part of the functional equation resulting from the variational principle is bounded and (weak) coercive — these conditions are sufficient for the existence of a solution element.