in this paper, a new molecular-structure descriptor, the general sum–connectivity co–index  is considered, which generalizes the first zagreb co–index and the general sum–connectivity index of graph theory. we mainly explore the lower and upper bounds in termsof the order and size for this new invariant. additionally, the nordhaus–gaddum–type resultis also represented.

this is a descriptive survey to define the incidence of co-existing disease in patients undergoing eye surgery before   anesthesia in hospitals of the ministry of health and education in 1993.   in this survey 2000 patients ' records have been studied who were admitted 10 the hospitals. collecting of data   was done by checklist that contained questions about the condition of the heart and...

one of the increasingly important organizational considerations involves occupational health and staff safety. hence, it is crucial for the managers to identify the key organizational factors contributing to reduce work-related accidents. this study was conducted on 340 workers, employees, experts, supervisors, directors, and managers. the data evaluation involved a questionnaire while the anal...

clarithromycin (cla), a broad-spectrum macrolide, is a poorly soluble drug with dissolution rate limited absorption. the aim of this investigation was to prepare cla nanoparticles from a ternary ground mixture in the presence of sodium lauryl sulfate (sls) and polyvinyl pyrrolidone (pvp) as co-grinding water-soluble compounds, in order to improve the drug dissolution rate. different weight rati...

background : gb virus c (gbv-c) is a flavivirus that was characterized in 1995. the prevalence of gbv-c rna in hiv-in­fected subjects has not been previously studied in iran and was therefore determined. methods: we have investigated serum samples of 80 patients from imam khomeini hospital, tehran, iran, whose hiv in­fection was confirmed in our laboratory by western-blotting. we used nested-pc...

in comparison to the previous researches, zro2 nanoparticles with higher surface area (85 m2/g) have been synthesized in this research. the as-prepared zro2 nanoparticles by co-precipitation method were characterized with x-ray diffraction (xrd), scanning electron microscopy (sem) and transmission electron microscopy (tem). the surface area of the sample was characterized by bet method. the eff...