In step 2 of an electrophilic addition, the positively charged intermediate combines with (Y) that is electron-rich and usually an anion to form the second covalent bond.Step 2 is the same nucleophilic attack process found in an SN1 reaction.n step 2 of an electrophilic addition, the positively charged intermediate combines with (Y) that is electron-rich and usually an anion to form the second covalent bond.
A. The Sleep Test Optimization Program is prior. authorization initiative for Polysomnography (PSG). There are two types of sleep studies â (1) Attended. Sleep Studies - performed in an outside facility, office, sleep clinic or laboratory; and (2) Unattended.
Unattended home sleep studies are not appropriate and are not covered for the evaluation of. obstructive sleep apnea. Polysomnography is required for the evaluation of OSA, therefore, unattended home sleep studies are not covered.