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.
Thunderstorms most often form when a mass of warm, moist air collides with a mass of cool air, dry air, or both. <br /> If the wind speed and direction changes with altitude (a condition called wind shear), the storms may start rotating, which gives them the potential to produce tornadoes. Thunderstorms most often form when a mass of warm, moist air collides with a mass of cool air, dry air, or both.