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.
Do not call NCCPT to schedule your exam. You may take the exam as quickly as 72 hours from date of purchase (depending on facility availability) or up to 6 months from date of purchase. $79 proctor fee will be paid to PSI.