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.
A warm front occurs when a cold air mass retreats and is replaced by a warm air mass. Warm fronts typically bring some form of precipitation to the... A warm front occurs when a cold air mass retreats and is replaced by a warm air mass. Warm fronts typically bring some form of precipitation to the area. Rain and stormy weather is most likely along the border where the warm and cold fronts meet. The differences in temperatures often cause storms. In the winter months, this collision can lead to severe weather. Warm fronts with more stable air produce less rain than fronts with unstable air.