Evaporation of the pancake-vortex lattice in weakly-coupled layered superconductors

We calculate the melting line of the pancake-vortex system in a layered superconductor, interpolating between two-dimensional (2D) melting at high fields and the zero-field limit of single-stack evaporation. Long-range interactions between pancake vortices in different layers permit a mean-field approach, the ``substrate model'', where each 2D crystal fluctuates in a substrate potential due to the vortices in other layers. We find the thermal stability limit of the 3D solid, and compare the free energy to a 2D liquid to determine the first-order melting transition and its jump in entropy.Comment: 4 pages, RevTeX, two postscript figures incorporated using eps

Transition Between Ground State and Metastable States in Classical 2D Atoms

Structural and static properties of a classical two-dimensional (2D) system consisting of a finite number of charged particles which are laterally confined by a parabolic potential are investigated by Monte Carlo (MC) simulations and the Newton optimization technique. This system is the classical analog of the well-known quantum dot problem. The energies and configurations of the ground and all metastable states are obtained. In order to investigate the barriers and the transitions between the ground and all metastable states we first locate the saddle points between them, then by walking downhill from the saddle point to the different minima, we find the path in configurational space from the ground state to the metastable states, from which the geometric properties of the energy landscape are obtained. The sensitivity of the ground-state configuration on the functional form of the inter-particle interaction and on the confinement potential is also investigated

First-Order Melting and Dynamics of Flux Lines in a Model for YBa2_2Cu3_3O7−δ_{7-\delta}

We have studied the statics and dynamics of flux lines in a model for YBCO, using both Monte Carlo simulations and Langevin dynamics. For a clean system, both approaches yield the same melting curve, which is found to be weakly first order with a heat of fusion of about $0.02 k_BT_m$ per vortex pancake at a field of $50 {\rm kG}.$ The time averaged magnetic field distribution experienced by a fixed spin is found to undergo a qualitative change at freezing, in agreement with NMR and $\mu {\rm SR}$ experiments. Melting in the clean system is accompanied by a proliferation of free disclinations which show a clear B-dependent 3D-2D crossover from long disclination lines parallel to the c-axis at low fields, to 2D ``pancake'' disclinations at higher fields. Strong point pins produce a logarithmical $\ln t$ relaxation which results from slow annealing out of disclinations in disordered samples.Comment: 31 pages, latex, revtex, 12 figures available upon request, No major changes to the original text, but some errors in the axes scale for Figures 6 and 7 were corrected(new figures available upon request), to be published in Physical Review B, July 199

Driven vortices in 3D layered superconductors: Dynamical ordering along the c-axis

We study a 3D model of driven vortices in weakly coupled layered superconductors with strong pinning. Above the critical force $F_c$, we find a plastic flow regime in which pancakes in different layers are uncoupled, corresponding to a pancake gas. At a higher $F$, there is an ``smectic flow'' regime with short-range interlayer order, corresponding to an entangled line liquid. Later, the transverse displacements freeze and vortices become correlated along the c-axis, resulting in a transverse solid. Finally, at a force $F_s$ the longitudinal displacements freeze and we find a coherent solid of rigid lines.Comment: 4 pages, 3 postscript figure

Cutaneous lupus erythematosus after treatment with paclitaxel and bevacizumab for metastatic breast cancer: a case report

Abstract Introduction The monoclonal anti-vascular endothelial growth factor antibody bevacizumab is increasingly used in the treatment of several malignant tumors. The usual side effects of this drug are hypertension and proteinuria. Paclitaxel is widely used in the treatment of breast cancer and head and neck carcinomas. Neither of these two drugs typically causes skin disorders. Paclitaxel-related cutaneous lupus erythematosus has been described before, but in earlier cases patients had a history of autoimmune disease. Case presentation We report a case of a 65-year-old Caucasian woman who presented with cutaneous lupus erythematosus after receiving paclitaxel-bevacizumab combination treatment as first-line therapy for metastatic breast cancer. Her cutaneous symptoms and increased serum anti-SSA and anti-SSB antibodies disappeared shortly after the discontinuation of therapy. Conclusion We conclude that cutaneous lupus erythematosus can also be seen in patients without earlier anamnesis of autoimmune disorders and that, furthermore, bevacizumab might cause atypical cutaneous side effects.</p