نتایج جستجو برای: benzenoid systems

تعداد نتایج: 1183720  

Journal: :Discrete Applied Mathematics 1997
Wen-Chung Huang Bo-Yin Yang Yeong-Nan Yeh

An explicit, non-recursive formula for the Wiener index of any given benzenoid chain is derived, greatly speeding up calculations and rendering it manually manageable, through a novel envisioning of chains as ternary strings. Previous results are encompassed and two completely new and useful ones are obtained, a formula to determine Wiener indices of benzenoid chains in periodic patterns, and a...

Journal: :Chembiochem : a European journal of chemical biology 2006
David Kokel Ding Xue

Benzene is a human carcinogen that might act through both genotoxic and nongenotoxic mechanisms to promote tumorigenesis. The genotoxic effects of benzene are well established, however, its potential nongenotoxic roles in carcinogenesis are poorly understood. We find that benzene suppresses somatic apoptosis in C. elegans; this suggests a potential nongenotoxic mechanism by which this chemical ...

Journal: :Physical chemistry chemical physics : PCCP 2009
Arkadiusz Ciesielski Tadeusz M Krygowski Michał K Cyrański Michał A Dobrowolski Jun-ichi Aihara

Application of topological properties and graph theory to benzenoid hydrocarbons allowed us to construct an effective approach interpreting ring current formation in molecules when exposed to an external magnetic field. Transformation of unexcited canonical structures for molecules of 34 benzenoid hydrocarbons into circuit structures and then to directed circuit structures allowed us to define ...

Journal: :Plant physiology 2004
Jennifer Boatright Florence Negre Xinlu Chen Christine M Kish Barbara Wood Greg Peel Irina Orlova David Gang David Rhodes Natalia Dudareva

In vivo stable isotope labeling and computer-assisted metabolic flux analysis were used to investigate the metabolic pathways in petunia (Petunia hybrida) cv Mitchell leading from Phe to benzenoid compounds, a process that requires the shortening of the side chain by a C(2) unit. Deuterium-labeled Phe ((2)H(5)-Phe) was supplied to excised petunia petals. The intracellular pools of benzenoid/phe...

2010
Liwen Xiao Shubo Chen Zhijun Guo Qiao Chen

The geometric-arithmetic index of graph G is defined as GA(G) = ∑ uv∈E(G) 2 √ dudv du+dv , du (or dv) is the degree the vertex u (or v). The GA index of benzenoid systems and phenylenes are computed, a simple relation is established between the geometric-arithmetic of a phenylene and the corresponding hexagonal squeeze in this paper. Mathematics Subject Classification: 05C05, 05C12

Let $G$ be a molecular graph with vertex set $V(G)$, $d_G(u, v)$ the topological distance between vertices $u$ and $v$ in $G$. The Hosoya polynomial $H(G, x)$ of $G$ is a polynomial $sumlimits_{{u, v}subseteq V(G)}x^{d_G(u, v)}$ in variable $x$. In this paper, we obtain an explicit analytical expression for the expected value of the Hosoya polynomial of a random benzenoid chain with $n$ hexagon...

Journal: :Journal of Chemical Information and Computer Sciences 1997
Victor Chepoi Sandi Klavzar

Distance properties of molecular graphs form an important topic in chemical graph theory.1 To justify this statement just recall the famous Wiener index which is also known as the Wiener number. This index is the first2 but also one of the most important topological indices of chemical graphs. Its research is still very active; see recent reviews3,4 and several new results in a volume5 dedicate...

Journal: :International Journal of Quantum Chemistry 2021

Hexagonal chains are a special class of catacondensed benzenoid system and phenylene polycyclic aromatic compounds. Recently, A family Sombor indices was introduced by Gutman in the chemical graph theory. It had been examined that these may be successfully applied on modeling thermodynamic properties In this paper, we study expected values random hexagonal chains, consider some graphs such as g...

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