The original submission of this manuscript included a citation of one of the authors' patents . During the review process, we were alerted to the existence of another relevant patent. As is the norm, it was our intention that all references to any patents should be removed from the manuscript and replaced by the relevant original peer reviewed research. Unfortunately, the authors were not asked to do this and the manuscript was inadvertently published with the patent citation included.
In the interests of fairness, we cite the other patent in question in this Correction .
We fully acknowledge that this was an editorial error and apologize to the authors and reviewers for any inconvenience this has caused them.
US Patent 6,428,746
The pre-publication history for this paper can be accessed here: