Period 6 element heavy metal, lead is a neurotoxin that accumulates both in soft tissues and the bones. Lead poisoning has been documented from ancient Rome, ancient Greece, and ancient China. Bismuth is a chemical element with symbol Bi and atomic number 83. Bismuth, a trivalent other metal, chemically resembles arsenic and antimony. Elemental bismuth may occur naturally uncombined, although its sulfide and oxide form important commercial ores. The free element is 86% as dense as lead. It is a brittle metal with a silvery white color when newly made, but often seen in air with a pink tinge owing to the surface
C-rich stability element and U-rich compared to the predominantly C-rich human element. Despite this shift the murine alpha globin mRNA is still as stable due to a complementary change in the specificity of the poly(C)-binding protein. C-rich stability element The C-rich stability element is a short part of a gene sequence important for the proper synthesis of globin and several other human proteins. Differences in the stabilities of individual mRNAs can dramatically affect the overall level of expression for genes. Eukaryotic mRNAs can have half-lives that vary from as short as several minutes to as long as several days. In differentiating human erythroid