There are two models of protein folding that are currently being confirmed: 1  The diffusion collision model, in which a nucleus is formed, then the secondary structure is formed, and finally these secondary structures are collided together and pack tightly together.
ATT Validity Dates. 1  Each ATT is valid for a period of time specified by the BON/RB (the average length of an ATT is 90 days). 2  Once the BON/RB has declared you eligible to test and you receive your ATT, you must test within the validity dates on the ATT.
However, laws can change, and some states, like Louisiana, want you to take the MBLEx within two years of applying for a license. This means if you pass the MBLEx today and wait beyond two years to apply to Louisiana, a simple score report and $20 will not suffice. You would need to take the MBLEx again.