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Submitted on: 10 November 2008.
Revised on: 13 February 2009.
Accepted on: 24 March 2009.
___________________Contemporary Clinical Trials---ELSEVIER SCIENCE INC
Submitted on: 24 June 2009.
Revised on: 18 September 2009.
Accepted on: 30 October 2009.
___________________Contemporary Clinical Trials---ELSEVIER SCIENCE INC
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