In a normal demand DielsâAlder reaction, the dienophile has an electron-withdrawing group in conjugation with the alkene; in an inverse-demand scenario, the dienophile is conjugated with an electron-donating group.Dienophiles can be chosen to contain a masked functionality.n a normal demand DielsâAlder reaction, the dienophile has an electron-withdrawing group in conjugation with the alkene; in an inverse-demand scenario, the dienophile is conjugated with an electron-donating group.
A standard echocardiogram or a fetal echocardiogram test usually takes about 30 to 60 minutes. A stress echocardiogram usually takes between 60 and 90 minutes.
Traditionally, in order to diagnose the cause of an episode a patient might undergo: 1  a history and physical examination. 2  blood tests. 3  a resting 12 lead electrocardiogram (ECG), 4  24 to 48 hours of continuous ambulatory cardiac monitoring (with a Holter monitor),  external cardiac event monitoring for up to a 1  month. echocardiogram (âechoâ)