Bilateral papillopathy as a presenting sign of pheochromocytoma associated with von Hippel–Lindau disease

Veeral Shah, Leonid Zlotcavitch, Angela M Herro, Sander R Dubovy, Zohar Yehoshua, Byron L LamBascom Palmer Eye Institute, University of Miami, Miller School of Medicine, Miami, FL, USAAbstract: A 7-year-old girl presented with decreased vision in both eyes for 1 month. Examination showed visual acuity of 20/50 and 20/60, no afferent pupillary defect, cecocentral scotomas, and bilateral optic disc edema with extensive peripapillary and macular exudates. Magnetic resonance imaging showed multiple cortical and subcortical white matter lesions. Both the laboratory workup and the systemic examination were unrevealing. However, on follow-up, the patient showed episodic elevations of blood pressure as high as 240/160. Further workup revealed elevated urine catecholamines and a right supra-adrenal mass proven to be a pheochromocytoma by histopathologic analysis. The paroxysmal hypertension resolved, and the visual acuity, visual fields, fundus exam, and neuroimaging improved. The patient was lost to follow-up until age 18 when she developed shortness of breath and was found to have multiple pulmonary metastases identified as pheochromocytoma by biopsy. Genetic testing identified a 3p25-26 (c.482 G>A) VHL gene chromosomal mutation consistent with von Hippel–Lindau disease genotype. Multiple peripheral retinal vascular dilations and small retinal capillary hemangioblastomas were also found. This case highlights the importance of recognizing the lability of blood pressure often seen with pheochromocytomas, which may mask the underlying cause of hypertensive papillopathy and retinopathy, a diagnosis of low clinical suspicion in the pediatric population. The case also underscores the importance of thorough systemic workup, including genotyping to detect conditions where pheochromocytoma may be the presenting sign of the disease, such as multiple endocrine neoplasia 2A and 2B, von Hippel–Lindau disease, von Recklinghausen disease, tuberous sclerosis, and Sturge–Weber syndrome.Keywords: hypertensive encephalopathy, VHL, pheochromocytoma, paroxysmal hypertensio

57.Elaboration and characterization of urchin-like Zinc Oxide Nanowires for photovoltaic applications

International audienc

Conception des oursins à base de nanofils de ZnO pour des applications en photovoltaïques

International audienc

Elaboration and characterization of urchin-like zinc oxide nanowires for photovoltaic applications

International audienc

Wavelength-scale light concentrator made by direct 3D laser writing of polymer metamaterials

International audienceWe report on the realization of functional infrared light concentrators based on a thick layer of air-polymer metamaterial with controlled pore size gradients. The design features an optimum gradient index profile leading to light focusing in the Fresnel zone of the structures for two selected operating wavelength domains near 5.6 and 10.4 μm. The metamaterial which consists in a thick polymer containing air holes with diameters ranging from λ/20 to λ/8 is made using a 3D lithography technique based on the two-photon polymerization of a homemade photopolymer. Infrared imaging of the structures reveals a tight focusing for both structures with a maximum local intensity increase by a factor of 2.5 for a concentrator volume of 1.5 λ3, slightly limited by the residual absorption of the selected polymer. Such porous and flat metamaterial structures offer interesting perspectives to increase infrared detector performance at the pixel level for imaging or sensing applications

Near-Field and Far-Field Sensitivities of LSPR Sensors

International audienceThe present study compares the near-field and far-field sensitivities of localized surface plasmon resonance (LSPR) sensors. To put into evidence the difference between far-field and near-field sensors, optical extinction measurements have been performed on gold nanoparticle gratings coated with dielectric superstrates of varying thicknesses. The potential of LSPR sensors is usually considered to lie in the near-field regime. Therefore, a comparison of the near-field sensitivities for gold nanoparticle gratings and continuous gold films of 50 nm in thickness is provided. The difference in refractive index sensitivities of both sensors is discussed in relation with the decay length of the evanescent near-field. SPRs sensors are usually considered more sensitive than LSPRs in terms of the m factor, refractive index sensitivity. We argue that the m factor sensitivity can only be defined for thick (15--100 nm) superstrates; for thin superstrates (d < 15 nm), the decay length of the evanescent field must be taken into account to properly compare both sensors

Enhancing LSPR sensitivity of Au gratings through graphene coupling to Au film

A particular interesting plasmonic system is that of metallic nanostructures interacting with metal films. As the localized surface plasmon resonance (LSPR) behavior of gold nanostructures (Au NPs) on the top of a gold thin film is exquisitely sensitive to the spacer distance of the film-Au NPs, we investigate in the present work the influence of a few-layered graphene spacer on the LSPR behavior of the NPs. The idea is to evidence the role of few-layered graphene as one of the thinnest possible spacer. We first show that the coupling to the Au film induces a strong lowering at around 507 nm and sharpening of the main LSPR of the Au NPs. Moreover, a blue shift in the main LSP resonance of about 13 nm is observed in the presence of a few-layered graphene spacer when compared to the case where gold nanostructures are directly linked to a gold thin film. Numerical simulations suggest that this LSP mode is dipolar and that the hot spots of the electric field are pushed to the top corners of the NPs, which makes it very sensitive to surrounding medium optical index changes and thus appealing for sensing applications. A figure of merit of such a system (gold/graphene/Au NPs) is 2.8, as compared to 2.1 for gold/Au NPs. This represents a 33 % gain in sensitivity and opens-up new sensing strategies