Roentgen equivalent man has been defined since 1976 as equal to 0.01 sievert, which is the more commonly used SI unit outside the United States. A number of earlier definitions going back to 1945 were derived from the roentgen unit, which was named after Wilhelm Röntgen, a German scientist who discovered X-rays. The acronym is now a misleading historical artifact, since 1 roentgen actually deposits about 0.96 rem in soft biological tissue, when all weighting factors equal unity. Older units of rem following other definitions are up to 17% smaller than the modern rem. One rem carries with it a 0.05% chance of
Sanford Burnham Prebys Medical Discovery Institute In 2007, T. Denny Sanford gave the Institute $20 million through Sanford Health, a hospital which received significant donations from T. Denny Sanford previously, allowing it to create the Sanford Children's Health Research Center, which has sites in Sioux Falls, South Dakota and La Jolla, CA, the latter within the campus of SBP. In 2010, the Institute adopted the name Sanford-Burnham Medical Research Institute following a $50 million pledge of support from Sanford. An anonymous gift of $275 million was made in 2014. In 2015, the Institute changed its name again to Sanford Burnham Prebys Medical Discovery Institute following a