Vibrational surface EELS probes confined Fuchs-Kliewer modes

Recently, two reports have demonstrated the amazing possibility to probe vibrational excitations from nanoparticles with a spatial resolution much smaller than the corresponding free-space phonon wavelength using electron energy loss spectroscopy (EELS). While Lagos et al. evidenced a strong spatial and spectral modulation of the EELS signal over a nanoparticle, Krivanek et al. did not. Here, we show that discrepancies among different EELS experiments as well as their relation to optical near- and far-field optical experiments can be understood by introducing the concept of confined bright and dark Fuchs-Kliewer modes, whose density of states is probed by EELS. Such a concise formalism is the vibrational counterpart of the broadly used formalism for localized surface plasmons; it makes it straightforward to predict or interpret phenomena already known for localized surface plasmons such as environment-related energy shifts or the possibility of 3D mapping of the related surface charge densities

Bridging nano-optics and condensed matter formalisms in a unified description of inelastic scattering of relativistic electron beams

In the last decades, the blossoming of experimental breakthroughs in the domain of electron energy loss spectroscopy (EELS) has triggered a variety of theoretical developments. Those have to deal with completely different situations, from atomically resolved phonon mapping to electron circular dichroism passing by surface plasmon mapping. All of them rely on very different physical approximations and have not yet been reconciled, despite early attempts to do so. As an effort in that direction, we report on the development of a scalar relativistic quantum electrodynamic (QED) approach of the inelastic scattering of fast electrons. This theory can be adapted to describe all modern EELS experiments, and under the relevant approximations, can be reduced to any of the last EELS theories. In that aim, we present in this paper the state of the art and the basics of scalar relativistic QED relevant to the electron inelastic scattering. We then give a clear relation between the two once antagonist descriptions of the EELS, the retarded green Dyadic, usually applied to describe photonic excitations and the quasi-static mixed dynamic form factor (MDFF), more adapted to describe core electronic excitations of material. We then use this theory to establish two important EELS-related equations. The first one relates the spatially resolved EELS to the imaginary part of the photon propagator and the incoming and outgoing electron beam wavefunction, synthesizing the most common theories developed for analyzing spatially resolved EELS experiments. The second one shows that the evolution of the electron beam density matrix is proportional to the mutual coherence tensor, proving that quite universally, the electromagnetic correlations in the target are imprinted in the coherence properties of the probing electron beam.Comment: Re-Submission to SciPost. Updated version: minor revisions, SciPost templat

Visualizing plasmon-exciton polaritons at the nanoscale using electron microscopy

Polaritons are compositional light-matter quasiparticles that have recently enabled remarkable breakthroughs in quantum and nonlinear optics, as well as in material science. Despite the enormous progress, however, a direct nanometer-scale visualization of polaritons has remained an open challenge. Here, we demonstrate that plasmon-exciton polaritons, or plexcitons, generated by a hybrid system composed of an individual silver nanoparticle and a few-layer transition metal dichalcogenide can be spectroscopically mapped with nanometer spatial resolution using electron energy loss spectroscopy in a scanning transmission electron microscope. Our experiments reveal important insights about the coupling process, which have not been reported so far. These include nanoscale variation of Rabi splitting and plasmon-exciton detuning, as well as absorption-dominated extinction signals, which in turn provide the ultimate evidence for the plasmon-exciton hybridization in the strong coupling regime. These findings pioneer new possibilities for in-depth studies of polariton-related phenomena with nanometer spatial resolution

Characterization of dry stone walls to out-of-plane actions

Este artigo apresenta o trabalho experimental para a caracterização de paredes de alvenaria de pedra (granito) para ações fora do plano. A parede tem uma configuração em U e o aparelho é de junta seca. Procura-se com este ensaio identificar a capacidade resistente e de deformação, o padrão de fendilhação, os mecanismos de colapso da alvenaria de pedra.This paper presents the experimental work for the characterization of the out-of-plane behavior of stone (granite) masonry walls. The wall has a U-shape and the bond in dry joint masonry. Based on test results the resistance and deformation capacity, crack pattern, collapse mechanism and hysteretic behavior are analyzed

Predictors of cardiac involvement in idiopathic inflammatory myopathies

Copyright © 2023 Bandeira, Dourado, Melo, Martins, Fraga, Ferraro, Saraiva, Sousa, Parente, Soares, Correia, Almeida, Dinis, Pinto, Oliveira Pinheiro, Rato, Beirão, Samões, Santos, Mazeda, Chícharo, Faria, Neto, Lourenço, Brites, Rodrigues, Silva-Dinis, Dias, Araújo, Martins, Couto, Valido, Santos, Barreira, Fonseca and Campanilho-Marques. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.Objectives: Idiopathic inflammatory myopathies (IIM) are a group of rare disorders that can affect the heart. This work aimed to find predictors of cardiac involvement in IIM. Methods: Multicenter, open cohort study, including patients registered in the IIM module of the Rheumatic Diseases Portuguese Register (Reuma.pt/Myositis) until January 2022. Patients without cardiac involvement information were excluded. Myo(peri)carditis, dilated cardiomyopathy, conduction abnormalities, and/or premature coronary artery disease were considered. Results: 230 patients were included, 163 (70.9%) of whom were females. Thirteen patients (5.7%) had cardiac involvement. Compared with IIM patients without cardiac involvement, these patients had a lower bilateral manual muscle testing score (MMT) at the peak of muscle weakness [108.0 ± 55.0 vs 147.5 ± 22.0, p=0.008] and more frequently had oesophageal [6/12 (50.0%) vs 33/207 (15.9%), p=0.009] and lung [10/13 (76.9%) vs 68/216 (31.5%), p=0.001] involvements. Anti-SRP antibodies were more commonly identified in patients with cardiac involvement [3/11 (27.3%) vs 9/174 (5.2%), p=0.026]. In the multivariate analysis, positivity for anti-SRP antibodies (OR 104.3, 95% CI: 2.5-4277.8, p=0.014) was a predictor of cardiac involvement, regardless of sex, ethnicity, age at diagnosis, and lung involvement. Sensitivity analysis confirmed these results. Conclusion: Anti-SRP antibodies were predictors of cardiac involvement in our cohort of IIM patients, irrespective of demographical characteristics and lung involvement. We suggest considering frequent screening for heart involvement in anti-SRP-positive IIM patients.info:eu-repo/semantics/publishedVersio

Pacientes com Covid-19 grave e complicações tromboembólicas / Patients with severe Covid-19 and thromboembolic complications

INTRODUÇÃO: O coronavírus-2 associado à Síndrome da Angústia Respiratória Aguda Grave (SARS-CoV-2), agente etiológico da doença por coronavírus 2019 (COVID-19) foi documentado como uma pandemia pelo Organização Mundial da Saúde (OMS) no início de março de 2020, e no início de abril havia mais de 1,5 milhão de casos em todo o mundo, com mais de 90.000 mortes; OBJETIVOS: Dessa forma, em vista de elucidar a incidência do (1) perfil, (2) drogas de uso recreativo, (3) comorbidades, (4) achados laboratoriais, (5) evento tromboembólico, (6) terapia de anticoagulação, (7) desfecho e correlacionar essas evidências em pacientes com COVID-19 grave em UTI, foi realizado o presente estudo. METODOLOGIA: Trata-se de um estudo de caráter exploratório, ecológico, transversal e retrospectivo. Utilizou-se os descritores: “Embolism and Thrombosis OR Heart disease AND Covid-19” na primeira base de dados, pesquisados de acordo com o MeSH, e “doenças cardiovasculares AND covid-19” na segunda base de dados, pesquisados de acordo com o DeCS.; RESULTADOS: idade média de 58 anos; sexo mais prevalente foi o masculino (83%); a droga de uso recretivo mais usado foi tabaco (30%); comorbidade mais prevalente foi a HAS (43%); achado laboratorial mais presente foi o dímero-D; o evento tromboembólico mais frequente foi o TEP (37%); terapia de anticoagulação mais usada foi a heparina de baixo peso molecular; e a taxa de óbito foi de 23%; CONCLUSÃO: Portanto, percebe-se que os achados do presente estudo se assemelham bastante aos dados da literatura vigente, apesar de suas limitações