Centrality is one of the most studied concepts in network analysis. Despite an abundance of methods for measuring centrality in social networks has been proposed, each approach exclusively characterizes limited parts of what it implies for an actor to be “vital” to the network. In this paper, a novel mechanism is proposed to quantitatively measure centrality using the re-defined entropy centrality model, which is based on decompositions of a graph into subgraphs and analysis on the entropy of neighbor nodes. By design, the re-defined entropy centrality which describes associations among node pairs and captures the process of influence propagation can be interpreted explained as a measure of actor potential for communication activity. We evaluate the efficiency of the proposed model by using four real-world datasets with varied sizes and densities and three artificial networks constructed by models including Barabasi-Albert, Erdos-Renyi and Watts-Stroggatz. The four datasets are Zachary’s karate club, USAir97, Collaboration network and Email network URV respectively. Extensive experimental results prove the effectiveness of the proposed method.

Measuring centrality has recently attracted increasing attention, with algorithms ranging from those that simply calculate the number of immediate neighbors and the shortest paths to those that are complicated iterative refinement processes and objective dynamical approaches. Indeed, vital nodes identification allows us to understand the roles that different nodes play in the structure of a network. However, quantifying centrality in complex networks with various topological structures is not an easy task. In this paper, we introduce a novel definition of entropy-based centrality, which can be applicable to weighted directed networks. By design, the total power of a node is divided into two parts, including its local power and its indirect power. The local power can be obtained by integrating the structural entropy, which reveals the communication activity and popularity of each node, and the interaction frequency entropy, which indicates its accessibility. In addition, the process of influence propagation can be captured by the two-hop subnetworks, resulting in the indirect power. In order to evaluate the performance of the entropy-based centrality, we use four weighted real-world networks with various instance sizes, degree distributions, and densities. Correspondingly, these networks are adolescent health, Bible, United States (US) airports, and Hep-th, respectively. Extensive analytical results demonstrate that the entropy-based centrality outperforms degree centrality, betweenness centrality, closeness centrality, and the Eigenvector centrality.

Our goal was to construct novel tissue-engineered blood vessels by using rabbit bone marrow mesenchymal stem cells (MSCs) and vascular acellular matrices, and to investigate their biocompatibility and patency rates. Isolated and cultured MSCs from rabbits were seeded on decellularized scaffolds. Thirty-six rabbits were randomly divided into three groups: tissue-engineered, vascular acellular matrix, and allogeneic artery groups. A 1-cm section of the abdominal aorta was sheared and a vessel from each group was transplanted onto the sheared region. Three months after implantation, the patency rates were 90% and 80% for the tissue-engineered and vascular acellular matrix groups, respectively, which were superior to that of the allogeneic artery group (25%). Hematoxylin and eosin staining and scanning electron microscopy showed that internal, middle, and external membranes were clearly present in the tissue-engineered group; the membrane morphology was similar to that of a normal artery, and endothelial cells were covered completely. However, the endothelial cells were not covered completely in the vascular acellular matrix group. Moreover, mural thrombosis, mild proliferation of intima, and inflammatory cell infiltration were observed. The intima was thickened and necrotic in the allogeneic artery group, whereas lumens were stenotic and accompanied by a certain degree of thrombus organization.