80 GHz compact photonic microwave generation from a solitary distributed feedback laser on silicon

International audienceMicrowave generation at 80 GHz is achieved from a distributed feedback laser on silicon made with a harmonic photonic potential from which a coherent beating between confined modes occurs. These results pave the way for all-optical microwave generation using compact and energy efficient semiconductor devices

A fluorescent membrane tension probe

Cells and organelles are delimited by lipid bilayers in which high deformability is essential to many cell processes, including motility, endocytosis and cell division. Membrane tension is therefore a major regulator of the cell processes that remodel membranes, albeit one that is very hard to measure in vivo. Here we show that a planarizable push-pull fluorescent probe called FliptR (fluorescent lipid tension reporter) can monitor changes in membrane tension by changing its fluorescence lifetime as a function of the twist between its fluorescent groups. The fluorescence lifetime depends linearly on membrane tension within cells, enabling an easy quantification of membrane tension by fluorescence lifetime imaging microscopy. We further show, using model membranes, that this linear dependency between lifetime of the probe and membrane tension relies on a membrane-tension-dependent lipid phase separation. We also provide calibration curves that enable accurate measurement of membrane tension using fluorescence lifetime imaging microscopy

Vaccination titres pre- and post-transplant in paediatric renal transplant recipients and the impact of immunosuppressive therapy

BACKGROUND: Avoidance of vaccine-preventable infections in paediatric renal allograft recipients is of utmost importance. However, the development and maintenance of protective vaccination titres may be impaired in this patient population owing to their need for immunosuppressive medication.METHODS: In the framework of the Cooperative European Paediatric Renal Transplant Initiative (CERTAIN), we therefore performed a multi-centre, multi-national study and analysed vaccination titres pre- and post-transplant in 155 patients with serial titre measurements in comparison with published data in healthy children.RESULTS: The percentage of patients with positive vaccination titres before renal transplantation (RTx) was low, especially for diphtheria (38.5%, control 75%) and pertussis (21.3%, control 96.3%). As few as 58.1% of patients had a hepatitis B antibody (HBsAb) titre &gt;100 IU/L before RTx. 38.1% of patients showed a vaccination titre loss post-transplant. Patients with an HBsAb titre between 10 and 100 IU/L before RTx experienced a significantly (p &lt; 0.05) more frequent hepatitis B vaccination titre loss post-transplant than patients with an HBsAb titre &gt;100 IU/L. The revaccination rate post-transplant was low and revaccination failed to induce positive titres in a considerable number of patients (27.3 to 83.3%). Treatment with rituximab was associated with a significantly increased risk of a vaccination titre loss post-transplant (odds ratio 4.26, p = 0.033).CONCLUSIONS: These data show a low percentage of patients with positive vaccination titres pre-transplant, a low revaccination rate post-transplant with limited antibody response, and a high rate of vaccination titre losses.</p