Portraits of the 2024 Nobel laureates in Physiology or Medicine, Victor Ambros and Gary Ruvkun, are seen at the Karolinska Institute in Stockholm, Sweden, on Oct. 7, 2024. The 2024 Nobel Prize in Medicine was awarded Monday to two American scientists, Victor Ambros and Gary Ruvkun, for their discovery of microRNA and its role in post-transcriptional gene regulation. (Xinhua/Peng Ziyang)