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.
Since a tornado is a spinning column of air with an axis of rotation, the tornado itself is a vortex. Some tornadoes also contain smaller vortices call suction vortices. Theseâ¦ vortices circle with the rotation of the main vortex and carve curved paths of more severe damage within the main damage path. A tornado with such features is called a multiple vortex tornado.