objective(s): the structure- activity relationship of a series of 36 molecules, showing l-type calcium channel blocking was studied using a qsar (quantitative structure–activity relationship) method. materials and methods: structures were optimized by the semi-empirical am1 quantum-chemical method which was also used to find structure-calcium channel blocking activity trends. several types of d...

hyrcanian forests are the most valuable forests in the north of iran and industrial harvesting occurs only in this area. it is a productive region near the southern coast of caspian sea. in these forests mixed beech stands mostly shown uneven-aged structure that is managed under selection system. in order to determine the priority of uneven aged method not only from an ecological view, but also...

in this paper energy bands and berry curvature of graphene was studied. desired hamiltonian regarding the next-nearest neighbors obtained by tight binding model. by using the second quantization approach, the transformation matrix is calculated and the hamiltonian of system is diagonalized. with this hamiltonian, the band structure and wave function can be calculated. by using calculated wave f...

the quantitative structure-property relationship (qspr) method is used to develop the correlation between structures of refrigerants (198 compounds) and their critical temperature. molecular descriptors calculated from structure alone were used to represent molecular structures. a subset of the calculated descriptors selected using a genetic algorithm (ga) was used in the qspr model development...

in this article, non radial method of dynamic dea with the parallel network structure is presented and is used for calculation of relative efficiency measures when inputs and outputs do not change equally. in this model, dmu divisions under evaluation have been put together in parallel. but its dynamic structure is assumed in series. since in real applications there are undesirable inputs and o...

this paper has revised the combined model of chan & qi with supply chain operations reference (scor) .this combined model with hierarchical structure, has three levels and seven criteria that some criteria are quantitative (cost, use of source) and others of them are qualitative (quality, flexibility, tangible, validity and innovation). in order to improvement of this model, this paper has comb...

north-east khorasan is one of the most active regions in the world because of is setting on the alpine-himalayan belt. historical and geological backgrounds suggest that this region has experienced many destructive earthquakes throughout history. compared with the historical background, the seismicity of the region, in the present century, is better known both from the macroseismic and instrume...

the theory of urban ecology is based on explaining urban spatial structure, studying and describing the reciprocal relationship between human societies in the urban areas and the environment, as well as analyzing the circumstances of urban population segregation and production of everyday life spaces. to study and explain urban ecological structure of mashhad, the case study of the article, we ...

background drug design against human immunodeficiency virus type 1 (hiv-1) integrase through its mechanistic study is of great interest in the area in biological research. the main obstacle in this area is the absence of the full-length crystal structure for hiv-1 integrase to be used as a model. a complete structure, similar to hiv-1 of a prototype foamy virus integrase in complex with dna, in...