The Deepwater Horizon spill was one of the largest oil spills in recorded history, depositing more than 2.6 million gallons of oil a day over the course of 84 days into the Gulf of Mexico, and with it considerable unprecedented problems and concerns. With an eventual total of 172 million gallons leaked into the Gulf, the Deepwater Horizon spill disrupted the ecology and deeply affected wildlife populations along 690 miles of U.S. coastline.Although the volume of oil spilled from the Exxon Valdez tanker represents only a small fraction of that from Deepwater Horizon, Exxon Valdez cleanup efforts took decades and the effects of the spill on wildlife are still being observed today.

Throughout the past 20 years, a prostate cancer screening pathway has been constructed and refined to diagnose prostate cancer. Although one primary pathway for screening prostate cancer has been developed and refined within the past 20 years, there remain many problems with this pathway, including a general lack of sensitivity and specificity; an inability to diagnose the progression of the disease; a significant risk presented to screening patients resulting from confirmatory diagnostic testing; and a lack of evidence supporting the reduction in prostate cancer mortality resulting from screening.

Human immunodeficiency virus (HIV) has one of the highest incidence and mortality rates of any infectious disease, with more than 33 million people infected worldwide. Specifically, HIV causes the destruction of helper T cells, ultimately resulting in the suppression of the immune system and leaving its human host susceptible to countless other pathogenic agents. The development of an effective HIV vaccine has continued for more than 20 years. But the use of preventative vaccines using traditional vaccine technologies, which have proven successful for other diseases, has thus far failed with HIV.