Tools to extract information I have set of technical sentences extracted from few research papers. 

e.g., Via analyzing the peer feedback content, it was found that the feedback provided by the mixed mode group was of better quality than that provided by the "peer comments" group; that is, the former provided more detailed feedback to individuals than the latter.

I want to extract the entities in the sentences and the relationships that take part with the identified. (e.g., SOV relationships)

What are the tools that I can use to efficiently extract them?
Open Calais is a free-to-use tool for entity recognition and relationship mapping. It's from Thompson-Reuters so may not be wholly suitable for technical language but worth a try. Has python bindings