نتایج جستجو برای: catacondensed benzenoid

تعداد نتایج: 488  

Journal: :DEStech Transactions on Environment, Energy and Earth Sciences 2021

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 ...

2005
Guillem Portella Jordi Poater Miquel Solà

The local aromaticity of a series of benzenoid systems was determined through the use of structurally (HOMA) and magnetically (NICS) based measures, and also by using a new electronically based indicator of aromaticity, the para-delocalization index (PDI). The results were compared with the predictions of Clar’s aromatic -sextet rule. It is found that, for all analyzed benzenoid hydrocarbons ha...

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...

Journal: :Applied Mathematics and Computation 2020

2003
Juan Rada Oswaldo Araujo Ivan Gutman

A new parameter, related to and easily determined from the structure of a benzenoid system and that of a phenylene – the number of inlets (r) – is introduced. The connectivity (Randi}) index of both benzenoid systems and phenylenes is then shown to depend solely on the number of vertices and on r. A simple relation is established between the connectivity index of a phenylene and of the correspo...

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...

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