There's growing evidence ...Fentanyl (or hydromorphone) have a better side effect profile than morphine (remember the vaunted vasodilation is only a side effect) thereby making fentanyl a better choice..
The subatomic particles in the nucleus of a carbon atom are protons and neutrons. The atomic nucleus contains protons and usually neutrons (except for hydrogen-1 (protium) atoms. The number of protons is an element's atomic number and is the same for all atoms of an element. Carbon has atomic number #6#. So all atoms of carbon have #6# protons in their atomic nuclei.
A neutron's location in an atom is in the core, or nucleus, of that atom, this nucleus is made of both neutrons and protons. the electrons of an atom are located in the electron http://wiki.answers.com/Q/Describe_the_location_of_protons_neutrons_and_electrons_in_an_atom# that surrounds the nucleus