Recombinant HIV-1 Tat Protein (89.6)

For a set S subset of V(G) in a network G, the Steiner distance d(G)(S) of S is the minimum size among all connected subnetworks whose vertex sets contain S. The Steiner k-eccentricity epsilon(kappa) (v) of a vertex v of G is the maximum Steiner distance among all k-vertex set S which contains the vertex v, i.e., s k (v) = max{d(S) vertical bar S subset of V(G), vertical bar S vertical bar = kappa, v is an element of S}. Based on Steiner keccentricity, the connective Steiner k-eccentricity index is introduced. As a newly structural invariant, some properties of the connective Steiner 3-eccentricity index are investigated. Firstly we present an O(n(2))-polynomial time algorithm to calculate the connective Steiner 3-eccentricity index of trees. Secondly some optimal problems among some network classes are discussed. As its application, finally we consider the network similarity measure based on the connective Steiner 3-eccentricity index. By two different methods, we study its advantages. Numerical results show that the measure based on the connective Steiner 3-eccentricity index has more advantages than the ones based on other topological indices (graph energy, Randic index, the largest adjacent eigenvalue, the largest Laplacian eigenvalue). (C) 2020 Elsevier Inc. All rights reserved.

Imidazolidin-2-one and 1,3-benzodiazepin-2-one scaffolds are structural motifs of many biologically active compounds. Herein, we report a highly regioselective acid-catalyzed intramolecular nucleophilic cyclization/intermolecular electrophilic substitution reaction sequence of (2,2-dialkoxyethyl)ureas. The reaction benefits from readily available starting materials, a simple workup procedure, moderate to high yields of target compounds, and provides a convenient entry to previously unknown 4-(het)arylimidazolidinones and 5-(het)arylbenzodiazepinones. The proposed mechanism of the reaction is also discussed.