26 research outputs found
Room-temperature InAs/InP Quantum Dots laser operation based on heterogeneous â2.5 Dâ Photonic Crystal
International audienceThe authors report on the design, fabrication and operation of heterogeneous and compact "2.5 D" Photonic Crystal microlaser with a single plane of InAs quantum dots as gain medium. The high quality factor photonic structures are tailored for vertical emission. The devices consist of a top two-dimensional InP Photonic Crystal Slab, a SiO 2 bonding layer, and a bottom high index contrast Si/SiO 2 Bragg mirror deposited on a Si wafer. Despite the fact that no more than about 5% of the quantum dots distribution effectively contribute to the modal gain, room-temperature lasing operation, around 1.5”m, was achieved by photopumping. A low effective threshold, on the order of 350”W, and a spontaneous emission factor, over 0.13, could be deduced from experiments
Exogenous LRRK2G2019S induces parkinsonian-like pathology in a nonhuman primate
Parkinsonâs disease (PD) is the second most prevalent neurodegenerative disease among the elderly. To understand pathogenesis and to test therapies, animal models that faithfully reproduce key pathological PD hallmarks are needed. As a prelude to developing a model of PD, we tested the tropism, efficacy, biodistribution, and transcriptional impact of canine adenovirus type 2 (CAV-2) vectors in the brain of Microcebus murinus, a nonhuman primate that naturally develops neurodegenerative lesions. We show that introducing helper-dependent (HD) CAV-2 vectors results in long-term, neuron-specific expression at the injection site and in afferent nuclei. Although HD CAV-2 vector injection induced a modest transcriptional response, no significant adaptive immune response was generated. We then generated and tested HD CAV-2 vectors expressing LRRK2 (leucine-rich repeat kinase 2) and LRRK2 carrying a G2019S mutation (LRRK2G2019S), which is linked to sporadic and familial autosomal dominant forms of PD. We show that HD-LRRK2G2019S expression induced parkinsonian-like motor symptoms and histological features in less than 4 months
Effect of H-implantation in the local elastic properties of silicon crystals
International audienceIn contrast to previous reports, where the modification of elastic constants of semiconductors irradiated with heavy ions was related to crystalline to amorphous transition, here we show that hydrogen implantation causes a dramatic modification of the shear modulus of Si at relatively low levels of crystalline damage. To study the system, we developed an alternative and rather general method to determine the shear modulus of the buried implanted layer. We use elasticity theory to link two simple measurements: (i) the wafer curvature to extract the in-plane stresses and (ii) x-ray diffraction to determine strains in the implanted layer
Room-temperature InAs/InP Quantum Dots laser operation based on heterogeneous â25 Dâ Photonic Crystal
Membrane Dynamics and Signaling of the Coxsackievirus and Adenovirus Receptor
International audienc