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.
The earliest date on which you can take the NCLEX-RNÂ® exam varies depending on your state, but the majority of students test approximately 45 days after the date of their graduation. Variables include: when you submit the applications and fees, the length of time the ATT is valid, personal factors (weddings, births, vacations), and job requirements.