The construction of a nanozyme that mimics the natural enzyme is a promising strategy to obtain a highly stable catalyst. Laccases are members of copper-containing oxidases, as an environmental catalysis,...

LKB1 is a Ser/Thr kinase that plays an important role in controlling both energy metabolism and cell polarity in metazoan organisms. LKB1 is also a tumor suppressor, and homozygous, inactivating mutations are found in a wide range of human cancers. In lung cancer, inactivating mutations are found in 10 to 50% of cases, but the consequences of functional loss in this context are poorly understood. We report here that LKB1 is required for the maturation of apical junctions in the human bronchial epithelial cell line 16HBE14o-(16HBE). This activity is dependent on an interaction with the Rho guanine nucleotide exchange factor p114RhoGEF but is independent of LKB1 kinase activity. Together, LKB1 and p114RhoGEF control RhoA activity in these cells to promote apical junction assembly.

In this paper, star-shaped honeycombs are analyzed in terms of their equivalent mechanical behaviors and band gap properties. Firstly, by applying Castigliano’s second theorem, the effective Young’s modulus and Poisson’s ratio are derived by an analytical method used in structural mechanics. On the basis of Bloch’s theorem, the dispersion characteristics are then analyzed by the dynamic matrix in conjunction with the Wittrick–Williams (W–W) algorithm. It should be noted that the presented method can form a more simple stiffness and mass matrices of the proposed structures, compared with the traditional finite element (FE) method. Thereafter, the effects of the geometrical parameters on the effective constants and band gaps are investigated and discussed. Numerical results demonstrate that the negative Poisson’s ratio provides an enhanced effective Young’s modulus of the considered honeycombs. Furthermore, the band gap exists in a much lower frequency region with an unchanged summing band gap width when the Poisson’s ratio is in negative values. In general, the work can serve as a guide for the optimal design of cellular structures.

No abstract