• A concise (150 to 250 words) abstract is required at the beginning of each article and, at the discretion of the chief editors, at the beginning of appropriate shorter contributions. Authors should summarize their conclusions and methods in the abstract.

• The abstract should not contain any undefined abbreviations, footnotes, reference citations, and urls or hyperlinks.

• Please note the abstract text in the manuscript must match exactly the abstract text entered in the abstract field of the upload system. If the abstract text entered in the abstract field of the upload system does not match the abstract in the manuscript, the submission will be returned to the author for correction.