Direct observation of spin rotation in Bragg scattering due to the spin-orbit interaction in silicon.

As a neutron scatters from a target nucleus, there is a small but measurable effect caused by the interaction of the neutron's magnetic dipole moment with that of the partially screened electric field of the nucleus. This spin-orbit interaction is typically referred to as Schwinger scattering and induces a small rotation of the neutron's spin on the order of 10 rad for Bragg diffraction from silicon. In our experiment, neutrons undergo greater than 100 successive Bragg reflections from the walls of a slotted, perfect-silicon crystal to amplify the total spin rotation.

The porphyrias.

The porphyrias are a group of disorders involving enzymatic defects in heme synthesis. The porphyrias classically manifest neuro-visceral or photocutaneous symptoms based on which enzyme in the heme metabolic pathway is deficient. Although rare, the porphyrias would most likely be encountered in the emergency department in patients presenting with chronic unspecified abdominal or musculoskeletal pain and those with new onset of psychiatric complaints.