Vortex Interactions and Thermally Induced Crossover from Type-I to Type-II Superconductivity

We have computed the effective interaction between vortices in the Ginzburg-Landau model from large-scale Monte-Carlo simulations, taking thermal fluctuations of matter fields and gauge fields fully into account close to the critical temperature. We find a change, in the form of a crossover, from attractive to repulsive effective vortex interactions in an intermediate range of Ginzburg-Landau parameters $\kappa \in [0.76-1]/\sqrt{2}$ upon increasing the temperature in the superconducting state. This corresponds to a thermally induced crossover from \typeI to \typeII superconductivity around a temperature $T_{\rm{Cr}}(\kappa)$, which we map out in the vicinity of the metal-to-superconductor transition. In order to see this crossover, it is essential to include amplitude fluctuations of the matter field, in addition to phase-fluctuations and gauge-field fluctuations. We present a simple physical picture of the crossover, and relate it to observations in \metal{Ta} and \metal{Nb} elemental superconductors which have low-temperature values of $\kappa$ in the relevant range.Comment: 9 pages, 6 figures. Accepted for publication in Physical Review

Steroid-sparing agents in giant cell arteritis

Background: Giant cell arteritis is the commonest form of medium-to-large vessel vasculitis, requiring long-term corticosteroid therapy. The short- and long-term side effects of corticosteroids are many, including weight gain, psychological effects, osteoporosis, cardiometabolic complications, and infections. Materials and Methods: Various agents used in place of or in combination with corticosteroids to reduce corticosteroid-related side effects were reviewed. However, considerable variation in practice was identified giving unclear guidance. This review included the most recent evidence on methotrexate, mycophenolate mofetil, azathioprine, cyclophosphamide, abatacept, and tocilizumab Results and Discussion: Also discussed are encouraging results with tocilizumab in GCA patients. Amongst the agents available for steroid-sparing effects, tocilizumab demonstrated the most robust data and is consequently recommended as the agent of choice for steroid-sparing, for remission induction, remission maintenance, and treating relapsing and refractory cases of GCA.Published versio