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Let G be a connected hypergraph. The distance spectral radius of G is the largest eigenvalue of its distance matrix. The Wiener index of G is defined to be the sum of distances between every unordered pair of vertices of G. A connected k-uniform hypergraph G with n vertices and m edges is called bicyclic if n = m(k − 1) − 1. Firstly, we obtain a lower bound on the Wiener index of k-uniform bicyclic hypergraphs with n vertices. As an application, among all k-uniform bicyclic hypergraphs with n vertices, we determine the first four bicyclic hypergraphs with smallest distance spectral radii for k ≥ 4, and the bicyclic hypergraph with minimum distance spectral radius for k = 3. [ABSTRACT FROM AUTHOR]

In this paper, we determine the energies of complements of unitary one-matching bi-Cayley graphs over finite commutative rings. We also determine the energies of some one-matching bi-gcd-graphs as well as the energies of complements of some one-matching bi-gcd-graphs, which are generalizations of unitary one-matching bi-Cayley graphs. [ABSTRACT FROM AUTHOR]

Discrete-time Rayleigh-fading single-input single-output (SISO) and multiple-input multiple-output (MIMO) channels are considered, with no channel state information at the transmitter or the receiver. The fading is assumed to be stationary and correlated in time, but independent from antenna to antenna. Peak-power and average-power constraints are imposed on the transmit antennas. For MIMO channels, these constraints are either imposed on the sum over antennas, or on each individual antenna. For SISO channels and MIMO channels with sum power constraints, the asymptotic capacity as the peak signal-to-noise ratio (SNR) goes to zero is identified; for MIMO channels with individual power constraints, this asymptotic capacity is obtained for a class of channels called transmit separable channels. The results for MIMO channels with individual power constraints are carried over to SISO channels with delay spread (i.e., frequency-selective fading). Index Terms--Channel capacity, correlated fading, frequency-selective fading, low signal-to-noise ratio (SNR), multiple-input multiple-output (MIMO).

Let G be a digraph and A (G) be the adjacency matrix of G. Let D (G) be the diagonal matrix with outdegrees of vertices of G. For any real α ∈ [ 0 , 1 ] , define the matrix A α (G) as A α (G) = α D (G) + (1 − α) A (G). The largest modulus of the eigenvalues of A α (G) is called the A α spectral radius of G. In this paper, we determine the digraphs which attain the maximum (or minimum) A α spectral radius among all strongly connected digraphs with given parameters such as girth, clique number, vertex connectivity or arc connectivity. We also propose an open problem. [ABSTRACT FROM AUTHOR]

During the SecB stimulation of SecA ATPase activity, SecB interacts with SecA inducing a conformational change that favors ATP binding and hydrolysis. Data show that SecB-enhanced Seca ATPase activity is due to an increase in the ATP hydrolysis rate. Further, the conformation of the high-affinity nucleotide binding site is regulated by SecB.

Research has been conducted on the SecA from Escherichia coli, a component of the protein transport machinery. The use of the purified components and synthetic signal peptides in studying the SecB interactions with SecA and SecA-signal peptide complexes in vitro is described.