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.
When a cold air mass pushes into hot air it forms something called a cold front. Since cold air is denser that hot air, the cold air mass acts as a wedge that lifts the hot aiâ¦r. If the warm air is unstable enough this lifting will lead to the formation of thunderstorms, which are powered by the warm air.