Brewster quasi bound states in the continuum in all-dielectric metasurfaces from single magnetic-dipole resonance meta-atoms

Bound states in the continuum (BICs) are ubiquitous in many areas of physics, attracting especial interest for their ability to confine waves with infinite lifetimes. Metasurfaces provide a suitable platform to realize them in photonics; such BICs are remarkably robust, being however complex to tune in frequency-wavevector space.Here we propose a scheme to engineer BICs and quasi-BICs with single magnetic-dipole resonance meta-atoms. Upon changing the orientation of the magnetic-dipole resonances, we show that the resulting quasi-BICs,emerging from the symmetry-protected BIC at normal incidence, become transparent for plane-wave illumination exactly at the magnetic-dipole angle, due to a Brewster-like effect. While yielding infinite Q-factors at normalincidence(canonical BIC), these are termed Brewster quasi-BICs since a transmission channel is always allowed that slightly widens resonances at oblique incidences. This is demonstrated experimentally through reflectance measurements in the microwave regime with high-refractive-index mm-disk metasurfaces. Such Brewster-inspired configuration is a plausible scenario to achieve quasi-BICs throughout the electromagnetic spectrum inaccessible through plane-wave illumination at given angles, which could be extrapolated to other kind of waves.Comment: 15 pages, 7 figures; typos corrected, Figs. 3 & 5 modified, new Fig. 7 & references adde

Developing an AI IoT application with open software on a RISC-V SoC

RISC-V is an emergent architecture that is gaining strength in low-power IoT applications. The stabilization of the architectural extensions and the start of commercialization of RISC-V based SOCs, like the Kendryte K210, raises the question of whether this open standard will facilitate the development of applications in specific markets or not.In this paper we evaluate the development environments, the toolchain, the debugging processes related to the Sipeed MAIX Go development board, as well as the standalone SDK and the Micropython port for the Kendryte K210. The training pipeline for the built-in convolutional neural network accelerator, with support for Tiny YOLO v2, has also been studied. In order to evaluate all the above aspects in depth, two low-cost, low-power, IoT edge applications based on AI have been developed. The first one is capable of recognizing movement in a house and autonomously identify whether it was caused by a human or by a house pet, like for example a dog or a cat. In the context of the current COVID-19 pandemic, the second application is capable of labeling whether a pedestrian is wearing a face mask or not, doing real-time object recognition at a mean rate of 13 FPS. Throughout the process, we can conclude that, despite the potential of the hardware and its excellent performance/cost ratio, the documentation for developers is scarce, the development environments are in low maturity levels, and the debugging processes are sometimes nonexistent

Enrofloxacin-based therapeutic strategy for the prevention of endometritis in susceptible mares

Enrofloxacin (EFX) is often used empirically to prevent uterine infections in mares in order to improve efficiency on Commercial Embryo Transfer Farms. This study investigated the uterine distribution of EFX and its metabolite ciprofloxacin (CFX) in mares and assessed the minimal inhibitory concentrations (MIC) of EFX against various common pathogens as a basis for establishing a rational dosing schedule. Plasma and uterine pharmacokinetic (PK) studies were performed in two groups (n = 5) of healthy mares following intravenous (i.v.) administration of EFX at either 2.5 and at 5 mg/kg bodyweight. Plasma and endometrial tissue samples, taken before for up to 48 h after treatment were analysed by Reverse Phase HPLC. MIC values for wild strains of Gram-negative (Escherichia coli, Pseudomonas aeruginosa) and Gram-positive bacteria (β-haemolytic streptococci) ranged from 0.25-2 and 1.5-3.0 μg/mL respectively. In terms of tissue distribution, the sum of the endometrial concentrations of the parent drug (EFX) and its active metabolite (CFX) (in terms of AUC), exceeded those in plasma by 249% and 941% following administration of EFX at 2.5 and 5 mg/kg respectively. After i.v. treatment with EFX at 5 mg/kg, endometrial concentrations of EFX and CFX above the MIC value were detected for 36-48 and 22-43 h posttreatment for Gram-negative and -positive isolates respectively. Concentrations above MIC were maintained for much shorter periods at the lower (2.5 mg/kg) treatment dose. Based on these results, a conventional dose (5 mg/kg) of EFX given prebreeding followed by two further doses at 36-48 h postbreeding are proposed as a rational strategy for using of EFX as a preventative therapy against a variety of common bacterial strains associated with equine endometritis.Fil: González, C. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias. Departamento de Fisiopatología. Laboratorio de Farmacología; ArgentinaFil: Moreno, L.. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias. Departamento de Fisiopatología. Laboratorio de Farmacología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Fumuso, E..Fil: García, J..Fil: Rivulgo, M..Fil: Confalonieri, A..Fil: Sparo, M..Fil: Sánchez Bruni, S.

Obstructive Sleep Apnoea Syndrome, Endothelial Function and Markers of Endothelialization. Changes after CPAP

STUDY OBJECTIVES: This study tries to assess the endothelial function in vivo using flow-mediated dilatation (FMD) and several biomarkers of endothelium formation/restoration and damage in patients with obstructive sleep apnoea (OSA) syndrome at baseline and after three months with CPAP therapy. DESIGN: Observational study, before and after CPAP therapy. SETTING AND PATIENTS: We studied 30 patients with apnoea/hypopnoea index (AHI) >15/h that were compared with themselves after three months of CPAP therapy. FMD was assessed non-invasively in vivo using the Laser-Doppler flowmetry. Circulating cell-free DNA (cf-DNA) and microparticles (MPs) were measured as markers of endothelial damage and the vascular endothelial growth factor (VEGF) was determined as a marker of endothelial restoration process. MEASUREMENTS AND RESULTS: After three month with CPAP, FMD significantly increased (1072.26 ± 483.21 vs. 1604.38 ± 915.69 PU, p< 0.005) cf-DNA and MPs significantly decreased (187.93 ± 115.81 vs. 121.28 ± 78.98 pg/ml, p<0.01, and 69.60 ± 62.60 vs. 39.82 ± 22.14 U/μL, p<0.05, respectively) and VEGF levels increased (585.02 ± 246.06 vs. 641.11 ± 212.69 pg/ml, p<0.05). These changes were higher in patients with more severe disease. There was a relationship between markers of damage (r = -0.53, p<0.005) but not between markers of damage and restoration, thus suggesting that both types of markers should be measured together. CONCLUSIONS: CPAP therapy improves FMD. This improvement may be related to an increase of endothelial restoration process and a decrease of endothelial damage

Étude de la corrosion du cuivre par microélectrochimie: Comparaison entre microélectrode et microcellule

Ce travail présente la comparaison de mesures électrochimiques réalisées à l'aide d'une microcellule et de microélectrodes conventionnelles. Des mesures de voltamétrie cyclique et d’impédances électrochimiques ont été réalisées sur des électrodes de cuivre pur, électrode classique couplée à des capillaires et microélectrodes, au potentiel de corrosion dans une solution NaCl 0,1 M, La comparaison entre ces deux types de mesure apporte des informations relatives à leurs sensibilités et limitations. En particulier, le domaine des basses fréquences du diagramme d’impédance est sensible à la géométrie de la microcellule ainsi qu'au positionnement relatif des électrodes