Papers should be submitted considering the fact that its content has not been published or submitted for publication elsewhere except as an abstract in a scientific meeting or congress. This must be stated in the cover letter. The covering letter must also contain an acknowledgment that all authors have contributed significantly and that all authors are in agreement with the content of the manuscript. Authors must declare any financial support or relationships with companies and should disclose any conflict of interest at the time of submission. Such information will be held in confidence while the paper is under review and will not affect the decision about acceptance or rejection of the paper. If tables or figures from previously published articles have been used in a submitted paper a letter from the copyright holder (the Publisher), permitting to reproduce the material, must be attached to the cover letter.