Fan is a type of Device. Fan is related to Electronic. Electronic is related to Cell. Cell is related to Plant. 
you are likely to find Senior in/at/on Hospital. Clinic is part of Hospital. you are likely to find Doctor in/at/on Clinic. 
Device <--IsA-- Fan <--RelatedTo--> Electronic <--RelatedTo--> Cell <--RelatedTo--> Plant 
Senior --AtLocation--> Hospital <--PartOf-- Clinic <--AtLocation-- Doctor 