a special class of cubic graphs are the cycle permutation graphs. a cycle permutation graph pn(α) is defined by taking two vertex-disjoint cycles on n vertices and adding a matching between the vertices of the two cycles.in this paper we determine a good upper bound for tenacity of cycle permutation graphs.

the total version of geometric–arithmetic index of graphs is introduced based on the endvertexdegrees of edges of their total graphs. in this paper, beside of computing the total gaindex for some graphs, its some properties especially lower and upper bounds are obtained.

INTRODUCTION Psychiatrists have been very reluctant to accept the idea that depressions, which they know so well, may be caused by allergies to common environmental molecules such as foods, airborne particles, and chemicals in water. When patients were depressed and anxious, and at the same time suffered from diseases accepted as allergic, psychosomatic explanations were used. This usually mean...

Tricyclic chemical structures are the core of many important drugs targeting all neurotransmitter pathways. These medicines enable effective therapies to treat from peptic ulcer disease psychiatric disorders. However, when administered systemically, they cause serious adverse effects that limit their use. To obtain localized and on-demand pharmacological action using light, we have designed pho...

the center (periphery) of a graph is the set of vertices with minimum (maximum)eccentricity. in this paper, the structure of centers and peripheries of some classes ofcomposite graphs are determined. the relations between eccentricity, radius and diameterof such composite graphs are also investigated. as an application we determinethe center and periphery of some chemical graphs such as nanotor...