This continuing series gathers and presents original research results on the leading edge of medicine and biology. Each article has been carefully selected in an attempt to present substantial topical data across a broad spectrum. Topics discussed include infant HIV and nanotechnology; self-expansion as an aid in smoking abstinence and cessation; gene silencing; the plausible role of antimicrobial peptides in periodontal disease; periodic leg movements in narcolepsy; the role of steroid hormones in brain development and visuospatial processing of adolescence and the future direction of cataract surgery.