Dextran‐based coating system for the immobilization of cell adhesion promoting molecules on titanium surfaces

Immobilization of adhesive peptides interacting with cellular integrin receptors onto metallic implant surfaces represents a promising approach to improve osseointegration of implants into the surrounding tissue. In the present study, a functional dextran‐based coating system consisting of an amino titanate adhesion promoter with dendritic structure and a carboxymethyl dextran was established to bind an RGD‐containing adhesive peptide via a selective coupling methodology onto titanium surfaces. The three‐step reaction procedure was characterized by X‐ray photoelectron spectroscopy. In cell adhesion experiments it could be demonstrated that dextran coatings containing immobilized RGD promote attachment and spreading of fibroblast and pre‐osteoblastic cells compared to native as well as CMD‐coated titanium surfaces without RGD. The direct attachment of the RGD sequence to the metal surface via the amino titanate adhesion promoter did not increase pre‐osteoblastic cell spreading, whereas coupling of RGD to the polymeric carboxy­methyl dextran layer slightly enhanced spreading of the cells.     

一类三维混沌系统的计算机仿真控制

提出了一种具有三维自治常微分方程组形式的新的类Chen系统,同时运用线性反馈,非线性反馈,微分反馈3种反馈方法,设计了3种不同的反馈控制器,对文中所提出的系统进行了控制,取得了满意的结果。最后通过理论分析和数值仿真实验证实了各方法的有效性,对文中论述进行了强有力的验证。