Correlation between Plasmonic and Thermal Properties of Metallic Nanoparticles.

Here, we investigate the correlation between the heat generated by gold nanoparticles, in particular nanospheres and nanobipyramids, and their plasmonic response manifested by the presence of Localized Surface Plasmon Resonances (LSPRs). Using a tunable laser and a thermal camera, we measure the temperature increase induced by colloidal nanoparticles in an aqueous solution as a function of the excitation wavelength in the optical regime. We demonstrate that the photothermal performances of the nanoparticles are strongly related not only to their plasmonic properties but also to the size and shape of the nanoparticles. The contribution of the longitudinal and transversal modes in gold nanobipyramids is also analyzed in terms of heat generation. These results will guide us to design appropriate nanoparticles to act as efficient heat nanosources.

Surface enhanced resonant Raman scattering in hybrid MoSe2@Au nanostructures.

We report on the surface enhanced resonant Raman scattering (SERRS) in hybrid MoSe2@Au plasmonic-excitonic nanostructures, focusing on the situation where the localized surface plasmon resonance of Au nanodisks is finely tuned to the exciton absorption of monolayer MoSe2. Using a resonant excitation, we investigate the SERRS in MoSe2@Au and the resonant Raman scattering (RRS) in a MoSe2@SiO2 reference. Both optical responses are compared to the non-resonant Raman scattering signal, thus providing an estimate of the relative contributions from the localized surface plasmons and the confined excitons to the Raman scattering enhancement. We determine a SERRS/RRS enhancement factor exceeding one order of magnitude. Furthermore, using numerical simulations, we explore the optical near-field properties of the hybrid MoSe2@Au nanostructure and investigate the SERRS efficiency dependence on the nanodisk surface morphology and on the excitation wavelength. We demonstrate that a photothermal effect, due to the resonant plasmonic pumping of electron-hole pairs into the MoSe2 layer, and the surface roughness of the metallic nanostructures are the main limiting factors of the SERRS efficiency.

Childhood opsoclonus-myoclonus syndrome: A case series from Tunisia.

INTRODUCTION: Opsoclonus myoclonus syndrome (OMS) is a rare immune-mediated disorder characterized by opsoclonus, myoclonus, ataxia and behavioral changes. The aim of our study was to investigate the epidemiology, clinical features, etiological aspects and outcome of OMS in Tunisian children. METHODS: We conducted a retrospective study over 11years (2005-2016) including all patients aged under 18years who were managed for newly diagnosed OMS in a tertiary care research centre for children with neurological symptoms. Epidemiological and clinical data were analyzed. RESULTS: Fifteen patients were included. The male-female ratio was 7:8. Median age of onset was 4.32years (range: 14months-16years). Time to diagnosis ranged between 2days and 10months. Median follow-up period was 3.8years (range: 2-6years). Acute ataxia was the preponderant inaugural feature. Mean severity score was 9 (range: 3-14). In "Tumor group" (n=7), the main underlying malignancy was neuroblastoma identified in 5 patient. In "No tumor group" (n=8), parainfectious and idiopathic OMS were identified in 5 and 3 patients, respectively. All patients received immunomodulatory treatment. Complete recovery of OMS symptoms was obtained in 12 children. Comparing the "Tumor group" and the "No tumor group", there were no differences in age of onset, sex ratio, main presenting symptom, median OMS severity score or responsiveness to treatment. However, sleep and behavioral disturbances were more frequent in the "No tumor group" (p=0.04). Neurological sequelae were equally found in both groups. CONCLUSION: Annual incidence of OMS in Tunisia could be estimated as 0.6 patients in children per million per year. Diagnosis may be challenging especially when the triad is incomplete. Although behavioral disturbances seem to be more frequent in the "No tumor group", our study suggests that there is no specific features differentiating paraneoplastic OMS from non paraneoplastic OMS. Acute symptoms are responsive to immunomodulatory treatment but long term follow up can reveal neurological (mainly cognitive) sequelae.