Biologically speaking, senescence is the process of deterioration that follows the development of an organism. In 1965, Leonard Hayflick discovered that normal diploid cells divide in cell culture about 50 times before entering a senescence phase during which they can replicate no more. Each cell division shortens the telomere of the cell's DNA, thus ticking back an "inner clock" for each subsequent copy of the cell. How does this mechanism protect the body from disease?
Back in the day
In June 1890, shortly before the artist's death, Vincent Van Gogh created two versions of a painting depicting his doctor, Paul Gachet. The paintings, called Portrait of Dr. Gachet, portray the doctor seated beside a foxglove plant, an extract of which is used to treat heart conditions. In 1990, 100 years after it was first painted, Japanese businessman Ryoei Saito purchased one version of the work for the record sum of $82.5 million. Why did he later threaten to have the painting burned?
Born on a day like today
Curie was a chemist who studied crystallography, magnetism, piezoelectricity, and radioactivity. He and his wife Marie worked to isolate polonium and radium and were the first to use the term 'radioactivity,' pioneering its study. He and one of his students discovered nuclear energy by identifying the continuous emission of heat from radium particles. Pierre and Marie were awarded the Nobel Prize in physics in 1903. How many other Curies have received Nobel Prizes?