This study on the structure-activity relationship of polymyxin B, a cyclic peptide antibiotic, used sixteen synthetic polymyxin B(3) analogs including alanine scanning analogs to elucidate the contribution of the side chains to antimicrobial activity and lipopolysaccharide (LPS) binding. Of these analogs, [Ala(5)]-polymyxin B(3) showed greatly reduced antimicrobial activity against Escherichia ...

We investigate the contribution of single cells to collective gamma-oscillations in a network of spiking neurons subject to an inhibitory activity control. In contrast to many earlier studies emphasizing a high precision in spike timing, cell ring is rather unreliable in our model. Nonetheless, we qualitatively reproduce many experimental ndings, some of them previously unexplored in modeling s...

in this paper we define a new type of rings ”almost powerhermitian rings” (a generalization of almost hermitian rings) and establish several sufficient conditions over a ring r such that, every regular matrix admits a diagonal power-reduction.

In this study we tried to define incidence and types of chromosomal aberrations (CAs) caused by radiotherapy (RT) in circulating lymphocytes from patients with lung cancer. For this purpose, we used cumulative dose-effect relationship, and correlate these data with statistical parameters. CAs were evaluated in terms of chromosome break, dicentric, ring and chromosome gap. Abnormal metaphase num...

let $r$ be a ring‎, ‎and let $n‎, ‎d$ be non-negative integers‎. ‎a right $r$-module $m$ is called $(n‎, ‎d)$-projective if $ext^{d+1}_r(m‎, ‎a)=0$ for every $n$-copresented right $r$-module $a$‎. ‎$r$ is called right $n$-cocoherent if every $n$-copresented right $r$-module is $(n+1)$-coprese-nted‎, ‎it is called a right co-$(n,d)$-ring if every right $r$-module is $(n‎, ‎d)$-projective‎. ‎$r$ ...

the zero-divisor graph of a commutative ring r with respect to nilpotent elements is a simple undirected graph $gamma_n^*(r)$ with vertex set z_n(r)*, and two vertices x and y are adjacent if and only if xy is nilpotent and xy is nonzero, where z_n(r)={x in r: xy is nilpotent, for some y in r^*}. in this paper, we investigate the basic properties of $gamma_n^*(r)$. we discuss when it will be eu...

Abstract In this work, we define composite matrices which are derived from group rings. We extend the idea of G -codes to -codes. show that these codes ideals in a ring, where ring is finite commutative Frobenius and an arbitrary group. prove dual -code also -code. quasi-composite Additionally, study generator matrices, consist identity matrices. Together with well known extension method, neigh...

A free space optics based ring topology that transmits full-duplex data to four different nodes in the is proposed. The link designed such do not require a local optical source transmit uplink data. wavelength division multiplexed signal composed of wavelengths each modulated by downlink baseband using differential phase shift keying transmitted towards nodes. At node, extracted and received pu...