Sylvain Sergent

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OBJECTIVE To determine whether leukoaraiosis predicts morbidity and mortality. BACKGROUND Gait disturbance and leukoaraiosis both are common in the elderly. Gait disturbance predicts mortality. Leukoaraiosis may be a unifying factor to both gait disturbance and mortality. METHODS We followed 221 patients prospectively evaluated for severity of(More)
OBJECTIVES Leukoaraiosis, a radiological change of cerebral white matter thought to be caused by ischemia, is associated with gait disturbance. However, because of concomitant stroke and cerebral atrophy, the clinical relevance of leukoaraiosis is uncertain. We, therefore, sought to determine if leukoaraiosis is a predictor of gait disturbance after(More)
Quantum dots enable strong carrier confinement and exhibit a delta-function like density of states, offering significant improvements to laser performance and high-temperature stability when used as a gain medium. However, quantum dot lasers have been limited to photonic cavities that are diffraction-limited and further miniaturization to meet the demands(More)
We compare the quality factor values of the whispering gallery modes of microdisks (μ-disks) incorporating GaN quantum dots (QDs) grown on AlN and AlGaN barriers by performing room temperature photoluminescence (PL) spectroscopy. The PL measurements show a large number of high Q factor resonant modes on the whole spectrum, which allows us to identify the(More)
We study by microphotoluminescence the optical properties of single zinc-blende GaN/AlN quantum dots grown by droplet epitaxy. We show evidences of both excitonic and multiexcitonic recombinations in individual quantum dots with radiative lifetimes shorter than 2876 8 ps. Owing to large band offsets and a large exciton binding energy, the excitonic(More)
Nanowire-induced SiN photonic crystal (PhC) nanocavities specifically designed for the ultra-violet and visible range are investigated by three-dimensional finite-difference time-domain calculations. As opposed to their silicon PhC counterpart, we find that the formation of nanowire-induced two-dimensional (2D) SiN PhC nanocavities is more challenging(More)
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