Capitalize the first letter of each major word in titles and subtitles. Do not capitalize articles (eg, a, an, the), prepositions of 3 or fewer letters, coordinating conjunctions (and, or, for, nor, but), or the to in infinitives. Do capitalize a 2-letter verb, such as Is or Be. Exceptions are made for some expressions, such as compound terms from languages other than English and phrasal verbs:
Ethical Questions Surrounding In Vitro Fertilization
Permanent Duplex Surveillance of In Situ Saphenous Vein Bypasses
Choice of Stents and End Points for Treatment of De Novo Coronary Artery Lesions
Weighing In on Bariatric Surgery
Researchers Size Up Nanotechnology Risks
Universal Screening for Tuberculosis Infection: School’s Out!