TO-3 at Motorola around 1955. The lead spacing was originally intended to allow plugging the device into a then-common tube socket. The metal package can be attached to a heat sink, making it suitable for devices dissipating several watts of heat. Thermal compound is used to improve heat transfer between the device case and the heat sink. Since the device case is one of the electrical connections, an insulator may be required to electrically isolate the component from the heatsink. Insulating washers may be made of mica or other materials with good thermal conductivity. The case is used with high-power and
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