Computing Reduced Connectivity Indices of Certain Nanotubes

2018 ◽  
Vol 8 (11) ◽  
pp. 1174-1180 ◽  
Author(s):  
V. R. Kulli
Keyword(s):  
Connectivity Indices

The Antifungal Activity of Some Aliphatic and Aromatic Acids

1992 ◽  
Vol 57 (5) ◽  
pp. 1134-1142 ◽  
Author(s):  
Bohuslav Rittich ◽  
Marta Pirochtová ◽  
Jiří Hřib ◽  
Kamila Jurtíková ◽  
Petr Doležal
Keyword(s):  
Biological Activities ◽  
Pure Water ◽  
Water System ◽  
Penicillium Expansum ◽  
Aromatic Acids ◽  
Antifungal Activities ◽  
Aliphatic Acids ◽  
Significant Relationships ◽  
Physico Chemical ◽  
Connectivity Indices

The present paper deals with the relationship between biological activities of some aliphatic and aromatic acids and their physico-chemical parameters expressing the influence of hydrophobic factors. The test strain in the biotest of growth inhibition was the fungus Fusarium moniliforme CCMF-180 and Penicillium expansum CCMF-576. Significant relationship between antifungal activities of un-ionized form of aliphatic acids and their capacity factors (log k'0) extrapolated to pure water, partition coefficients determined in 1-octanol-water system (log Poct) and the first order of molecular connectivity indices (1χ) were calculated. The ionized form of aliphatic acids were antifungally active too. For benzoic acids significant relationships between antifungal activities and capacity factors of anionic form (log k'ia) were calculated.

scholarly journals Mathematical Properties of Variable Topological Indices

Symmetry ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 43
Author(s):  
José M. Sigarreta
Keyword(s):  
Real Number ◽  
Large Class ◽  
Symmetric Functions ◽  
Topological Indices ◽  
Current Interest ◽  
Zagreb Indices ◽  
Mathematical Properties ◽  
Connectivity Indices ◽  
Optimal Bounds ◽  
New Framework

A topic of current interest in the study of topological indices is to find relations between some index and one or several relevant parameters and/or other indices. In this paper we study two general topological indices Aα and Bα, defined for each graph H=(V(H),E(H)) by Aα(H)=∑ij∈E(H)f(di,dj)α and Bα(H)=∑i∈V(H)h(di)α, where di denotes the degree of the vertex i and α is any real number. Many important topological indices can be obtained from Aα and Bα by choosing appropriate symmetric functions and values of α. This new framework provides new tools that allow to obtain in a unified way inequalities involving many different topological indices. In particular, we obtain new optimal bounds on the variable Zagreb indices, the variable sum-connectivity index, the variable geometric-arithmetic index and the variable inverse sum indeg index. Thus, our approach provides both new tools for the study of topological indices and new bounds for a large class of topological indices. We obtain several optimal bounds of Aα (respectively, Bα) involving Aβ (respectively, Bβ). Moreover, we provide several bounds of the variable geometric-arithmetic index in terms of the variable inverse sum indeg index, and two bounds of the variable inverse sum indeg index in terms of the variable second Zagreb and the variable sum-connectivity indices.

scholarly journals The General (α,3)-Path Connectivity Indices of Polycyclic Aromatic Hydrocarbons

2018 ◽  
Vol 2018 ◽  
pp. 1-5
Author(s):  
Haiying Wang ◽  
Chuantao Li
Keyword(s):  
Applied Sciences ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Molecular Graph ◽  
Three Dimensional ◽  
3D Qsar ◽  
Medical Sciences ◽  
Connectivity Indices ◽  
Polycyclic Aromatic ◽  
Extremal Values

The general (α,t)-path connectivity index of a molecular graph originates from many practical problems such as three-dimensional quantitative structure-activity (3D QSAR) and molecular chirality. It is defined as Rtα(G)=∑Pt=vi1vi2⋯vit+1⊆G[d(vi1)d(vi2)⋯d(vit+1)]α, where the summation is taken over all possible paths of length t of G and we do not distinguish between the paths vi1vi2⋯vit+1 and vit+1⋯vi2vi1. In this paper, we focus on the structures of Polycyclic Aromatic Hydrocarbons (PAHn), which play a role in organic materials and medical sciences. We try to compute the exact general (α,3)-path connectivity indices of this family of hydrocarbon structures. Furthermore, we exactly derive the monotonicity and the extremal values of R3α(PAHn) for any real number α. These valuable results could produce strong guiding significance to these applied sciences.

scholarly journals Two theorems on connectivity indices

2002 ◽  
Vol 67 (2) ◽  
pp. 99-102 ◽  
Author(s):  
Ivan Gutman
Keyword(s):  
Connectivity Index ◽  
Connectivity Indices

Two general cases are pointed out for which the ordering of molecules according to the connectivity index C(?) is the same for all values of the exponent ?.

scholarly journals Ordering of alkane isomers by means of connectivity indices

2002 ◽  
Vol 67 (2) ◽  
pp. 87-97 ◽  
Author(s):  
Ivan Gutman ◽  
Dusica Vidovic ◽  
Anka Nedic
Keyword(s):  
Carbon Atom ◽  
Organic Molecule ◽  
Molecular Graph ◽  
Connectivity Index ◽  
Randić Index ◽  
Randic Index ◽  
Connectivity Indices ◽  
The Difference

The connectivity index of an organic molecule whose molecular graph is Gis defined as C(?)=?(?u?v)??where ?u is the degree of the vertex u in G, where the summation goes over all pairs of adjacent vertices of G and where ? is a pertinently chosen exponent. The usual value of ? is ?1/2, in which case ?=C(?1/2) is referred to as the Randic index. The ordering of isomeric alkanes according to ??follows the extent of branching of the carbon-atom skeleton. We now study the ordering of the constitutional isomers of alkanes with 6 through 10 carbon atoms with respect to C(?) for various values of the parameter ?. This ordering significantly depends on ?. The difference between the orderings with respect to ??and with respect to C(?) is measured by a function ??and the ?-dependence of ??was established.

scholarly journals Computation of Zagreb and atom-bond connectivity indices of certain families of dendrimers by using automorphism group action

2017 ◽  
Vol 82 (2) ◽  
pp. 151-162
Author(s):  
Uzma Ahmad ◽  
Sarfraz Ahmad ◽  
Rabia Yousaf
Keyword(s):  
Automorphism Group ◽  
Carbon Atom ◽  
Physicochemical Properties ◽  
Group Action ◽  
Chemical Compounds ◽  
Topological Indices ◽  
Zagreb Indices ◽  
Connectivity Indices ◽  
Atom Bond

In QSAR/QSPR studies, topological indices are utilized to predict the bioactivity of chemical compounds. In this paper, the closed forms of different Zagreb indices and atom?bond connectivity indices of regular dendrimers G[n] and H[n] in terms of a given parameter n are determined by using the automorphism group action. It was reported that these connectivity indices are correlated with some physicochemical properties and are used to measure the level of branching of the molecular carbon-atom skeleton.

Inhibition of Hill Reaction by 2-Azido-s-triazine Derivatives: QSAR Study with Molecular Connectivity Indices

1989 ◽  
Vol 44 (3-4) ◽  
pp. 255-261 ◽  
Author(s):  
Milan Š Šoškić ◽  
Aleksandar Sabljić
Keyword(s):  
Structural Features ◽  
Second Order ◽  
Fine Tuning ◽  
Superior Performance ◽  
Hill Reaction ◽  
Retention Data ◽  
Molecular Connectivity ◽  
Inhibitory Potency ◽  
Molecular Connectivity Indices ◽  
Connectivity Indices

Abstract 2-A zido-s-T riazines, Connectivity Indices. Inhibition of Hill Reaction. Photosystem II, OSAR Modelling This study was undertaken to find a simple and accurate structural parameters for the quantita­tive description of inhibitory potency of 2-azido-s-triazines in Hill reaction and to gain more information about the mechanism of inhibition on molecular level. A very good correlation (r = 0.946) was obtained between the pl50 values (the negative logarithm of the molar concentra­tion that causes 50% inhibition) and the valence zero-order and the difference between the second-order and the valence second-order molecular connectivity indices. This model, when com pared with the empirical models based on the 1-octano/water partition coefficients and the chromatographic retention data, shows superior performance in accuracy and range of applicabili­ty. In addition, the direct correspondence between molecular structure and above connectivity indices makes it possible to locate structural features responsible for the inhibitory potency of 2-azido-s-triazines in Hill reaction. From our OSAR analysis, the interaction between the chloro­plast receptor site and 2-azido-s-triazines, which causes inhibition of Hill reaction, is primarily influenced by the size of alkylamino substituents and it accounts for the most variation in the pl50 data. The structural features of secondary importance that control the magnitude of pl50’s are the polarity of alkylamino chains and the degree of branching on alpha carbon atom of R:alkylamino substituent. Com pared with the main factor, the size of alkylamino substituents, they can be viewed as a fine tuning elements for the inhibitory potency of 2-azido-s-triazines.

Internal Pressure and Molecular Connectivity Indices for Alkanes

1998 ◽  
Vol 14 (05) ◽  
pp. 407-412
Author(s):  
Zhang Guo-Zheng ◽  
◽  
Ying Xu-Gen ◽  
Liu Guo-Jie
Keyword(s):  
Internal Pressure ◽  
Molecular Connectivity ◽  
Molecular Connectivity Indices ◽  
Connectivity Indices
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