Shaping the Emission Directivity of Single Quantum Dots in Dielectric Nanodisks Exploiting Mie Resonances.

Manipulating the optical landscape of single quantum dots (QDs) is essential to increase the emitted photon output, enhancing their performance as chemical sensors and single-photon sources. Micro-optical structures are typically used for this task, with the drawback of a large size compared to the embedded single emitters. Nanophotonic architectures hold the promise to modify dramatically the emission properties of QDs, boosting light-matter interactions at the nanoscale, in ultracompact devices.

Imaging of Anatomical Variants Around the Wrist and Hand.

Wrist and hand anatomy may present several clinically relevant variants that involve bones, muscles, tendons, and nerves. Thorough knowledge of these abnormalities and their appearance in imaging studies is useful for proper management. In particular, it is necessary to differentiate the incidental findings that do not represent a trigger for a specific syndrome from those anomalies causing symptoms and functional impairment.

High-resolution ultrasound of peripheral neuropathies in rheumatological patients: An overview of clinical applications and imaging findings.

Peripheral neuropathies are surprisingly common and can be associated with a number of conditions, including rheumatological diseases. Whether the co-existence of peripheral neuropathies with rheumatological disorders is coincidental or related to a common pathogenic mechanism, these disabling conditions can affect the outcome of rheumatological patients and should be targeted with specific treatment. The clinical presentation of peripheral neuropathy can be multifaceted and difficult to recognize in polysymptomatic patients.

Vapour Liquid Solid Growth Effects on InGaN Epilayers Composition Uniformity in Presence of Metal Droplets.

We investigated the composition uniformity of InGaN epilayers in presence of metal droplets on the surface. We used Plasma Assisted MBE to grow an InGaN sample partially covered by metal droplets and performed structural and compositional analysis. The results showed a marked difference in indium incorporation between the region under the droplets and between them.

Strain Relaxation of InAs Quantum Dots on Misoriented InAlAs(111) Metamorphic Substrates.

We investigate in detail the role of strain relaxation and capping overgrowth in the self-assembly of InAs quantum dots by droplet epitaxy. InAs quantum dots were realized on an In0.6Al0.

High-resolution Doppler ultrasound in systemic sclerosis: Analysis of digital arteries and nailfold microvasculature using 18-5 MHz and 33-9 MHz probes.

Introduction: Newly developed Doppler techniques enable the sampling of slow vascular flows and the extrapolation of spectral parameters in distal arterioles. The aim of this study was to investigate the role of spectral analysis performed by means of ultra-high frequency ultrasound (US) in the evaluation of the peripheral vascular bed of systemic sclerosis (SSc) patients.

Methods: Both hands of 33 patients affected by diffuse cutaneous SSc and 34 volunteers were evaluated with a US machine equipped with 33-9 MHz and 18-5 MHz transducers.

High-Resolution Ultrasound of Facial Muscles: Sonoanatomy, Scanning Technique, and Pathological Cases.

The aim of the present work is to review the sonographic appearance of facial muscles with high-frequency transducers and to illustrate a step-by-step scanning technique that enables an effective evaluation of them. In addition, we highlighted the clinical application showing some pathological cases demonstrated with ultrasound (US). The recent technological advances have greatly enlarged the potential of high-resolution US in the evaluation of the face.

Medical Cannabis for Headache Pain: a Primer for Clinicians.

Purpose Of Review: Public acceptance of Cannabis sativa L. (cannabis) as a therapeutic option grows despite lags in both research and clinician familiarity. Cannabis-whether as a medical, recreational, or illicit substance-is and has been commonly used by patients.

High-resolution ultrasound of spigelian and groin hernias: a closer look at fascial architecture and aponeurotic passageways.

From the clinical point of view, a proper diagnosis of spigelian, inguinal and femoral hernias may be relevant for orienting the patient's management, as these conditions carry a different risk of complications and require specific approaches and treatments. Imaging may play a significant role in the diagnostic work-up of patients with suspected abdominal hernias, as the identification and categorization of these conditions is often unfeasible on clinical ground. Ultrasound imaging is particularly suited for this purpose, owing to its dynamic capabilities, high accuracy, low cost and wide availability.

Nucleation of Ga droplets self-assembly on GaAs(111)A substrates.

We investigated the nucleation of Ga droplets on singular GaAs(111)A substrates in the view of their use as the seeds for the self-assembled droplet epitaxial quantum dots. A small critical cluster size of 1-2 atoms characterizes the droplet nucleation. Low values of the Hopkins-Skellam index (as low as 0.

Progressive Multifocal Leukoencephalopathy in a Patient With Progressive Multiple Sclerosis Treated With Ocrelizumab Monotherapy.

Importance: Progressive multifocal leukoencephalopathy (PML) is an opportunistic infection caused by the JC virus that has no proven effective treatment. Although rare cases of PML have occurred with other anti-CD20 therapies, there had been no prior cases associated with ocrelizumab.

Objective: To report the first ever case of PML occurring with ocrelizumab monotherapy in a patient with progressive multiple sclerosis without prior immunomodulation.

Breast Metastases: Updates on Epidemiology and Radiologic Findings.

Purpose The aim of this study was to report the prevalence of secondary breast malignancies and analyze their radiological characteristics. Materials and methods We collected 42,505 pathological reports of mammary biopsies performed from January 2000 to January 2019 in our hospital database, from which we screened reports of secondary cancer of the breast. We collected and analyzed imaging data from computed tomography (CT), ultrasound (US), and mammography.

Fabrication of spectrally sharp Si-based dielectric resonators: combining etaloning with Mie resonances.

We use low-resolution optical lithography joined with solid state dewetting of crystalline, ultra-thin silicon on insulator (c-UT-SOI) to form monocrystalline, atomically smooth, silicon-based Mie resonators in well-controlled large periodic arrays. The dewetted islands have a typical size in the 100 nm range, about one order of magnitude smaller than the etching resolution. Exploiting a 2 µm thick SiO layer separating the islands and the underlying bulk silicon wafer, we combine the resonant modes of the antennas with the etalon effect.

Solid-State Dewetting Dynamics of Amorphous Ge Thin Films on Silicon Dioxide Substrates.

We report on the dewetting process, in a high vacuum environment, of amorphous Ge thin films on SiO/Si (001). A detailed insight of the dewetting is obtained by in situ reflection high-energy electron diffraction and ex situ scanning electron microscopy. These characterizations show that the amorphous Ge films dewet into Ge crystalline nano-islands with dynamics dominated by crystallization of the amorphous material into crystalline nano-seeds and material transport at Ge islands.

Opsoclonus-Myoclonus-Ataxia Syndrome Related to the Novel Coronavirus (COVID-19).

Supplemental Digital Content is Available in the Text.

Reentrant Behavior of the Density vs. Temperature of Indium Islands on GaAs(111)A.

We show that the density of indium islands on GaAs(111)A substrates have a non-monotonic, reentrant behavior as a function of the indium deposition temperature. The expected increase in the density with decreasing temperature, indeed, is observed only down to 160 ∘C, where the indium islands undertake the expected liquid-to-solid phase transition. Further decreasing the temperature causes a sizable reduction of the island density.

Infrared photodetector sensitized by InAs quantum dots embedded near an AlGaAs/GaAs heterointerface.

Mid-infrared sensors detect infrared radiation emitted from objects, and are actually widely used for monitoring gases and moisture as well as for imaging objects at or above room temperature. Infrared photodetectors offer fast detection, but many devices cannot provide high responsivity at room temperature. Here we demonstrate infrared sensing with high responsivity at room temperature.

High-temperature droplet epitaxy of symmetric GaAs/AlGaAs quantum dots.

We introduce a high-temperature droplet epitaxy procedure, based on the control of the arsenization dynamics of nanoscale droplets of liquid Ga on GaAs(111)A surfaces. The use of high temperatures for the self-assembly of droplet epitaxy quantum dots solves major issues related to material defects, introduced during the droplet epitaxy fabrication process, which limited its use for single and entangled photon sources for quantum photonics applications. We identify the region in the parameter space which allows quantum dots to self-assemble with the desired emission wavelength and highly symmetric shape while maintaining a high optical quality.

Droplet epitaxy quantum dot based infrared photodetectors.

The fabrication and characterization of an infrared photodetector based on GaAs droplet epitaxy quantum dots embedded in AlGaAs barrier is reported. The high control over dot electronic properties and the high achievable number density allowed by droplet epitaxy technique permitted us to realize a device using a single dot layer in the active region. Moreover, thanks to the independent control over dot height and width, we were able to obtain a very sharp absorption peak in the thermal infrared region (3-8 μm).

GaAs epilayers grown on patterned (001) silicon substrates via suspended Ge layers.

We demonstrate the growth of low density anti-phase boundaries, crack-free GaAs epilayers, by Molecular Beam Epitaxy on silicon (001) substrates. The method relies on the deposition of thick GaAs on a suspended Ge buffer realized on top of deeply patterned Si substrates by means of a three-temperature procedure for the growth. This approach allows to suppress, at the same time, both threading dislocations and thermal strain in the epilayer and to remove anti-phase boundaries even in absence of substrate tilt.

Temperature Activated Dimensionality Crossover in the Nucleation of Quantum Dots by Droplet Epitaxy on GaAs(111)A Vicinal Substrates.

A temperature activated crossover between two nucleation regimes is observed in the behavior of Ga droplet nucleation on vicinal GaAs(111)A substrates with a miscut of 2° towards [Formula: see text]. At low temperature (<400 °C) the droplet density dependence on temperature and flux is compatible with droplet nucleation by two-dimensional diffusion. Increasing the temperature, a different regime is observed, whose scaling behavior is compatible with a reduction of the dimensionality of the nucleation regime from two to one dimension.

Droplet epitaxy of semiconductor nanostructures for quantum photonic devices.

The long dreamed 'quantum internet' would consist of a network of quantum nodes (solid-state or atomic systems) linked by flying qubits, naturally based on photons, travelling over long distances at the speed of light, with negligible decoherence. A key component is a light source, able to provide single or entangled photon pairs. Among the different platforms, semiconductor quantum dots (QDs) are very attractive, as they can be integrated with other photonic and electronic components in miniaturized chips.

Droplet Controlled Growth Dynamics in Molecular Beam Epitaxy of Nitride Semiconductors.

The growth dynamics of Ga(In)N semiconductors by Plasma-Assisted Molecular Beam Epitaxy (PAMBE) at low temperatures (T = 450 °C) is here investigated. The presence of droplets at the growth surface strongly affects the adatom incorporation dynamics, making the growth rate a decreasing function of the metal flux impinging on the surface. We explain this phenomenon via a model that considers droplet effects on the incorporation of metal adatoms into the crystal.