Symmetry Breaking in Photonic Crystals: On-Demand Dispersion from Flatband to Dirac Cones.

We demonstrate that symmetry breaking opens a new degree of freedom to tailor energy-momentum dispersion in photonic crystals. Using a general theoretical framework in two illustrative practical structures, we show that breaking symmetry enables an on-demand tuning of the local density of states of the same photonic band from zero (Dirac cone dispersion) to infinity (flatband dispersion), as well as any constant density over an adjustable spectral range. As a proof of concept, we demonstrate experimentally the transformation of the very same photonic band from a conventional quadratic shape to a Dirac dispersion, a flatband dispersion, and a multivalley one. This transition is achieved by finely tuning the vertical symmetry breaking of the photonic structures. Our results provide an unprecedented degree of freedom for optical dispersion engineering in planar integrated photonic devices.

[Biomarkers in clinical immunology]. / Biomarqueurs en immunologie générale.

In a current perspective of individualized medicine, biomarkers appear as a simple and readily available aid to assist clinicians in the identification and monitoring of diseases whose diagnosis is difficult. Basically, we know the limited performance of medical history and of clinical examination; therefore, the use of laboratory tests is often seen as the panacea to solve the clinical enigma. The purpose of this article is to analyze a few biomarkers commonly processed in the immunology laboratory (AAN, ANCA, anti-tTG, rheumatoid factor and anti-CCP) and to review the principle, the usefulness and the performance of these tests in specific clinical situations. We will see that, far from supplanting history and physical examination, these immunological biomarkers take their full value as a supplement to clinical information!

Successful long-term outcome of the first combined heart and kidney transplant in a patient with systemic Al amyloidosis.

Simultaneous cardiac and renal involvement is associated with a particularly poor prognosis in patients with AL amyloidosis (AL-A). We report the first case of a successful long-term outcome of combined heart and kidney transplantation not followed by autologous stem cell transplantation in a patient with systemic AL-A. The recipient was a 46-year-old man with end-stage renal failure associated with serious cardiac involvement in the context of AL-A. Before transplantation, two courses of oral melphalan plus prednisone induced partial hematologic remission, as shown by the decrease in circulating free light chain with no improvement of renal or heart function. The patient underwent combined heart and kidney transplantation as a rescue treatment. During the follow-up period (36 months), plasma cell dyscrasia remains in complete remission, with normal free lambda light chain levels and no recurrence of amyloid deposition on heart and kidney grafts. This case report demonstrates that combined heart and kidney transplantation not systematically associated with stem cell transplantation may be considered an additional therapeutic option in AL-A patients with severe organ dysfunction and partial hematologic remission.

Necrotizing fasciitis during de novo minimal change nephrotic syndrome in a kidney transplant recipient.

Skin infections and particularly necrotizing fasciitis (NF) represent a rare but serious complication after transplantation. Optimal management depends on prompt diagnosis with identification of the causative organisms to allow appropriate antibiotic therapy in association with surgical debridement. We report a case of a methicillin-resistant Staphylococcus aureus (MRSA) NF as the single pathogen in a renal transplant recipient, during the course of a de novo minimal-change nephrotic syndrome, treated with high-dose steroids. Antibiotic therapy together with surgical debridement and discontinuation of immunosuppressive treatment led to a complete recovery, despite persistence of the nephrotic syndrome. The development of de novo minimal-change nephrotic syndrome after renal allograft transplantation should alert physicians to the possibility of MRSA NF during an increase in the immunosuppressive regimen.