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.
After you visit your doctor, share your symptoms and undergo a routine physical in which the physician listens to your heart and lungs, he or she may determine that you might have a heart valve disorder. An echocardiogram is typically ordered both to verify the diagnosis and to reveal the extent of the problem. As the echocardiogram uses sound waves, the technician and physician can view your heart beating. Typically a standard, two-dimensional echocardiogram takes about 30 minutes to complete.