Retraction Retraction dated 2016-09-20

Click to view Retraction: https://0-doi-org.brum.beds.ac.uk/10.1186/s40560-016-0185-9

Retraction Retraction dated 2016-04-27

Click to view Retraction: https://0-doi-org.brum.beds.ac.uk/10.1186/s40560-016-0140-9