Left atrial thrombus mimicking atrial myxoma on imaging studies in a patient with cardiac transplant

AbstractLeft atrial thrombus can develop in patients with atrial fibrillation and/or a dilated left atrium such as seen in patients with heart failure. In cardiac transplant patients with bi-atrial anastomosis, the suture line can be a potential nidus for thrombus formation. These thrombi can be either organized or unstable with ulcerated surfaces. We present a unique case of a left atrial mass in a cardiac transplant patient with features of atrial myxoma on imaging studies but found to be an organized thrombus on histopathology.<Learning objective: Left atrial thrombus formation in the cardiac transplant patient is a rare but serious condition. Most of the times it can be diagnosed with imaging studies but these noninvasive studies do not always give a definite diagnosis. We present a unique case of left atrial thrombus presenting as classic imaging features of atrial myxoma diagnosed after surgical resection. We emphasize that while treating these patients broad differential diagnosis should always be considered.

Multicolored devices fabricated by direct lithography of colloidal nanocrystals

Colloidal nanocrystals (NCs) are interesting as potential active medium for novel nanophotonic and nanoelectronic devices, due to their low fabrication costs and full tunability of their opto-electronic properties. In this work we report a multi step approach for the fabrication of multicolored micro- and nano- displays by localizing NCs through lithographic techniques without recurring to etching processes or surface treatment of the substrate. We demonstrate the possibility to localize different ensembles of emitters on the same substrate by realigned photolithographic steps or mix-and-match electron beam and photolithographic approaches. Moreover, fine tuning of the overall pixel emission is shown by varying the concentration ratio among localized red and green NCs. This technique enables the fabrication of optically pumped colored pixels with very high definition. Our approach combined with advances in NCs-based light emitting diodes technology will enable the electrical injection of advanced micro and nano light sources

Stress-driven AlN cantilever-based flow sensor for fish lateral line system

In this work, we report on the fabrication and characterization of stress-driven aluminum nitride (AlN) cantilevers to be applied as flow sensor for fish lateral line system. The fabricated structures exploit a multilayered cantilever AlN/molybdenum (Mo) and a Nichrome 80/20 alloy as piezoresistor. Cantilever arrays are realized by using conventional micromachining techniques involving optical lithography and etching processes. The fabrication of the piezoresistive cantilevers is reported and the operation of the cantilever as flow sensor has been investigated by electrical measurement under nitrogen flowing condition showing a sensitivity to directionality and to low value applied forces

High-Purcell-factor dipolelike modes at visible wavelengths in H1 photonic crystal cavity

The optimization of H1 photonic crystal cavities for applications in the visible spectral range is reported, with the goal to obtain a versatile photonic platform to explore strongly and weakly coupled systems. The resonators have been realized in silicon nitride and weakly coupled to both organic (fluorophores) and inorganic (colloidal nanocrystals) nanoparticles emitting in the visible spectral range. The theoretical Purcell factor of the two dipolelike modes in the defect has been increased up to approximately 90, and the experimental quality factor was measured to be approximately 750

Single colloidal quantum dots as sources of single photons for quantum cryptography

Colloidal nanocrystals, i.e. quantum dots synthesized trough wet-chemistry approaches, are promising nanoparticles for photonic applications and, remarkably, their quantum nature makes them very promising for single photon emission at room temperature. In this work we describe two approaches to engineer the emission properties of these nanoemitters in terms of radiative lifetime and photon polarization, drawing a viable strategy for their exploitation as room-temperature single photon sources for quantum information and quantum telecommunications

Design, fabrication and characterization of piezoelectric cantilever MEMS for underwater application

This work shows a preliminary microfabrication route for a novel directional hydrophone based on a cross-shaped design of piezoelectric cantilevers. A thin layer of aluminum nitride (AlN) using Molybdenum (Mo) thin film as electrodes will be exploited as piezoelectric functional layer for the microfabrication of a cantilever-based ultrasonic micro electro mechanical system (MEMS) hydrophone. A parameterized simulation based on length of these cantilevers between 100 and 1000 μm allowed to set the first resonant mode between 20 kHz and 200 kHz, the desired underwater ultrasonic acoustic range. The microsystem was designed with cantilevers facing each other in a cross configuration in order to have novel MEMS hydrophone with an omnidirectional response. In order to investigate the first resonance frequency mode and displacement measurements, a Laser Doppler Vibrometer was used and good agreement between simulations and experimental results was achieved. Responsivity and directionality measurements of the piezoelectric MEMS cantilevers were performed in water. Maximum sensitivity up to −153 dB with omnidirectional directivity pattern was achieved by fabricated MEMS sensor

Wearable piezoelectric mass sensor based on pH sensitive hydrogels for sweat pH monitoring

Colorimetric and electrochemical (bio)sensors are commonly employed in wearable platforms for sweat monitoring; nevertheless, they suffer from low stability of the sensitive element. In contrast, mass-(bio)sensors are commonly used for analyte detection at laboratory level only, due to their rigidity. To overcome these limitations, a flexible mass-(bio)sensor for sweat pH sensing is proposed. The device exploits the flexibility of piezoelectric AlN membranes fabricated on a polyimide substrate combined to the sensitive properties of a pH responsive hydrogel based on PEG-DA/CEA molecules. A resonant frequency shift is recorded due to the hydrogel swelling/shrinking at several pH. Our device shows a responsivity of about 12 kHz/pH unit when measured in artificial sweat formulation in the pH range 3-8. To the best of our knowledge, this is the first time that hydrogel mass variations are sensed by a flexible resonator, fostering the development of a new class of compliant and wearable devices

Silicon nitride PhC nanocavities as versatile platform for visible spectral range devices

Abstract We propose silicon nitride two-dimensional photonic crystal resonators as flexible platform to realize photonic devices based on spontaneous emission engineering of nanoemitters in the visible spectral range. The versatility of our approach is demonstrated by coupling the two dipole-like modes of a closed band gap H1 nanocavity with: (i) DNA strands marked with Cyanine 3 organic dyes, (ii) antibodies bounded to fluorescent proteins and (iii) colloidal semiconductor nanocrystals localized in the maximum of the resonant electric field. The experimental results are in good agreement with the numerical simulations, highlighting the good coupling of the nanocavities with both organic and inorganic light emitters