Class A (type D) CpG ODNs (CpG-A ODNs) contain a central palindromic phosphodiester (PO) CpG sequence and a PS-modified 3â poly-G tail. The poly G tails form intermolecular tetrads that result in high molecular weight ordered structures.
Why does a tornado form when cold and hot air meet? The collision of warm and cold air is not the direct cause of a tornado, nor is it absolutely necessary. When a cold air mass pushes into a warm air mass (this is called a câ¦old front) the warmer, less dense air is forced upwards.
Disrupt the airflow, take away its moisture or destroy its unstable balance of hot and cold air, and it can't function. Often, a tornado will die because the cold outflow of air from falling precipitation upsets the balance. Types of Tornadoes Tornadoes come from mainly two types of thunderstorms: supercell and non-supercell.