Karl Landsteiner blood group A nor of blood group B. Therefore, the immune systems of persons with blood group A, B or AB do not refuse the donation. Further, because persons with blood group AB do not form antibodies against either the antigens of blood group A or B, they can accept blood from persons with these blood groups, besides from persons with blood group O-negative. In today's blood transfusions only concentrates of red blood cells without serum are transmitted, which is of great importance in surgical practice. In 1930 Landsteiner was awarded the Nobel Prize in Physiology or Medicine in recognition
Nobel Prize controversies Chao was the first to experimentally identify positrons through electron–positron annihilation, but did not realize what they were. Anderson, Chao's classmate at Caltech, used the same radioactive source, , as Chao. (Historically, was known as "thorium C double prime" or "ThC", see decay chains.) Fifty years later, Anderson admitted that Chao had inspired his discovery: Chao's research formed the foundation from which much of Anderson's own work developed. Chao died in 1998, without sharing in a Nobel Prize acknowledgment. The 1923 prize went to Robert Millikan "for his work on the elementary charge of electricity and on the photoelectric effect".