The two-nucleon system at next-to-next-to-next-to-leading order

We consider the two-nucleon system at next-to-next-to-next-to-leading order (N^3LO) in chiral effective field theory. The two-nucleon potential at N^3LO consists of one-, two- and three-pion exchanges and a set of contact interactions with zero, two and four derivatives. In addition, one has to take into account various isospin-breaking and relativistic corrections. We employ spectral function regularization for the multi-pion exchanges. Within this framework, it is shown that the three-pion exchange contribution is negligibly small. The low-energy constants (LECs) related to pion-nucleon vertices are taken consistently from studies of pion-nucleon scattering in chiral perturbation theory. The total of 26 four-nucleon LECs has been determined by a combined fit to some np and pp phase shifts from the Nijmegen analysis together with the nn scattering length. The description of nucleon-nucleon scattering and the deuteron observables at N^3LO is improved compared to the one at NLO and NNLO. The theoretical uncertainties in observables are estimated based on the variation of the cut-offs in the spectral function representation of the potential and in the regulator utilized in the Lippmann-Schwinger equation.Comment: 62 pp, 13 fig

Comparison of Levothyroxine Bioequivalence Between Products

Class of 2006 AbstractBackground: Approximately 2% of the population has hypothyroidism, and are treated with a levothyroxine product. Unlike other medications, levothyroxine products have not been considered substitutable due to their narrow therapeutic window. Objectives: To compare the bioequivalence study findings from studies conducted by the manufacturer of Synthroid to those conducted by other investigators. Methods: Studies comparing levothyroxine product bioequivalence were found and divided according to time period, study design, and major funding party. Results: Ten studies excluded due to a change in Synthroid formulation. Six steady state studies and 3 single dose studies were left. Conclusions: Although data suggests bioequivalence between all studied levothyroxine products, there was not enough data to make a conclusion.This item is part of the Pharmacy Student Research Projects collection, made available by the College of Pharmacy and the University Libraries at the University of Arizona. For more information about items in this collection, please contact Jennifer Martin, Librarian and Clinical Instructor, Pharmacy Practice and Science, [email protected]