What is the fine-grained topic of the following text: Prof. Krastanka Marinova Ph.D. From 2007 until 2014 she worked as research associate in the Department of chemical and pharmaceutical engineering (DCPE), Faculty of Chemistry and Pharmacy of Sofia University "St. Kliment Ohridski". Only return the topic.
Prof. Krastanka Marinova's tenure as research associate in the Department of Chemical and Pharmaceutical Engineering at Sofia University.