J Med Internet Res

Background: Immune checkpoint inhibitors (ICIs) are increasingly used to treat several types of tumors. Impact of this emerging therapy on patients’ health-related quality of life (HRQoL) is usually collected in clinical trials through standard questionnaires. However, this might not fully reflect HRQoL of patients under real-world conditions. In parallel, users’ narratives from social media represent a potential new source of research concerning HRQoL. Objective: The aim of this study is to assess and compare coverage of ICI-treated patients’ HRQoL domains and subdomains in standard questionnaires from clinical trials and in real-world setting from social media posts. Methods: A retrospective study was carried out by collecting social media posts in French language written by internet users mentioning their experiences with ICIs between January 2011 and August 2018. Automatic and manual extractions were implemented to create a corpus where domains and subdomains of HRQoL were classified. These annotations were compared with domains covered by 2 standard HRQoL questionnaires, the EORTC QLQ-C30 and the FACT-G. Results: We identified 150 users who described their own experience with ICI (89/150, 59.3%) or that of their relative (61/150, 40.7%), with 137 users (91.3%) reporting at least one HRQoL domain in their social media posts. A total of 8 domains and 42 subdomains of HRQoL were identified: Global health (1 subdomain; 115 patients), Symptoms (13; 76), Emotional state (10; 49), Role (7; 22), Physical activity (4; 13), Professional situation (3; 9), Cognitive state (2; 2), and Social state (2; 2). The QLQ-C30 showed a wider global coverage of social media HRQoL subdomains than the FACT-G, 45% (19/42) and 29% (12/42), respectively. For both QLQ-C30 and FACT-G questionnaires, coverage rates were particularly suboptimal for Symptoms (68/123, 55.3% and 72/123, 58.5%, respectively), Emotional state (7/49, 14% and 24/49, 49%, respectively), and Role (17/22, 77% and 15/22, 68%, respectively). Conclusions: Many patients with cancer are using social media to share their experiences with immunotherapy. Collecting and analyzing their spontaneous narratives are helpful to capture and understand their HRQoL in real-world setting. New measures of HRQoL are needed to provide more in-depth evaluation of Symptoms, Emotional state, and Role among patients with cancer treated with immunotherapy

Cathodoluminescence de défauts dans le diamant naturel

We study two defects into natural semiconductor diamond. The first one emit a line positioned at 3.158 eV at 4 K : we assigne this luminescence to a transition between the excited and the ground state levels of the ND 1 centre. The second which emit in the range 3.8-4.581 eV and is characterized by a privileged coupling with one local phonon-mode, the energy of which is 236 meV, was named 5 RL by Wight [7]. We specify some features of its electronic structure and propose the identification to a carbon vacancy-acceptor complex.Nous étudions deux défauts dans le diamant naturel semiconducteur. La raie d'émission du premier, située à 3,158 eV à 4 K, est attribuable à une transition entre le niveau excité 4T1 et le niveau de base 4A2 du centre ND 1. Le second est positionné entre 3,8 et 4,581 eV et est caractérisé par un couplage privilégié avec un mode local de vibration d'énergie 236 meV : son spectre a été noté 5 RL par Wight [7]. Nous proposons l'identification à un complexe lacune de carbone-accepteur

Quantum wires obtained by dislocation slipping

Dislocation slipping is used as an atomic scale tool to cut a 5 nm GaAs single quantum well (QW) grown by MBE on a (001) GaAs substrate into quantum wires (QWW). Three point deformation bending is used to control dislocation slipping. The minimum value of the QWW widths is evaluated to 25 nm. PL studies after deformation show intense peak, shifted in regard to the undeformed SQW in good agreement with theory. Raman scattering results confirm the additional lateral confinement

Dislocation slipping, a new technique to produce step-like surfaces, compatible with quantum confinement sizes

We propose a method to generate steps at the surface of GaAs single crystals. This method is based on plasticity properties of GaAs. In the simple slip condition, the {$54\underline{1}$} surfaces exhibit a set of very long parallel lines (3 mm) along . T.E.M. observations of these surfaces by replica technique allow to observe very homogeneous regions, over 20 $\mu$m$^2$ with step height $h = 200$ Å  and step width $\ell = 400$ Å. Those geometrical dimensions are compatible with the quantum confinement and make the obtained surfaces alternate solutions to vicinal surfaces or high-index surfaces used to obtain quantum lines by direct growth.Nous proposons une méthode de génération de marches sur une surface de GaAs monocristallin. Cette méthode est basée sur la plasticité de monocristaux de GaAs. Dans les conditions de glissement simple, les surfaces {$54\underline{1}$} présentent un ensemble de lignes parallèles de grande longueur (3 mm) suivant . L'observation au M.E.T. de cette surface par la technique des répliques permet de voir des zones très homogènes sur plus de 20 $\mu$m$^2$, avec des marches de hauteur $h = 200$ Å  et de largeur $\ell = 400$ Å. Ces dimensions sont compatibles avec le confinement quantique et les surfaces ainsi obtenues sont une alternative aux surfaces vicinales ou à hauts indices utilisées pour la réalisation de fils quantiques par croissance directe

Effect of compensation on recombination into Si doped (Ga, Al)As

Using a time-resolved cathodoluminescence technique, we have investigated the radiative recombination in highly doped (Ga, Al)As epitaxial layers (the dopant was Si or Ge). We have realized in homogeneous Si-doped epitaxial (Ga, Al)As layers the conditions of large luminescence efficiency and great decay time usually observed in L.E.D. obtained by double liquid phase epitaxy of (Ga, Al)As on GaAs substrate. The phenomena are well explained if we consider the effect of charge impurity fluctuations in compensated semiconductors on the density of state tails at the edges of the band-gap.Au moyen d'une expérience de cathodoluminescence pulsée, nous avons étudié les recombinaisons radiatives dans des couches épitaxiées (Ga, Al) As fortement dopé ; le dopant est Si ou Ge. Dans des couches homogènes dopées au silicium nous avons obtenu les conditions de fort rendement lumineux et de longue durée de vie observées dans les diodes électroluminescentes réalisées par double épitaxie en phase liquide de (Ga, Al)As sur substrat GaAs. Les phénomènes sont bien expliqués en considérant l'effet des fluctuations des impuretés chargées dans les semiconducteurs fortement compensés sur les queues de densité d'états en bords de bande interdite

Analysis of the donor-acceptor recombination band in the photoluminescence spectra of CuInSe2

International audienceAn empirical relation is proposed to analyze the broad band observed in the photoluminescence spectra of CuInSe2 (CIS) due to donor-acceptor pair recombinations. This permits, together with the knowledge of the majority carrier concentration and the compensation ratio, the determination of the activation energy ED of the donor and EA of the acceptor levels and the mean distance R between D-A pairs. Values of the dielectric constant ϵ, ED and EA for CIS obtained with this model agree with reported data

Photoluminescence in p-type CuInSe2 single crystals

International audienc

Atomistic nature of heterointerfaces in III-V semiconductor-based quantum-well structures and its consequences for photoluminescence behavior

The atomistic nature of heterointerfaces in III-V semiconductor-based quantum-well structures is investigated via a combined effort comprised of (i) systematic experimental investigations of the well-width (dw) dependence of the photoluminescence (PL) linewidth (G) of GaAs/AlxGa1-xAs(100) single quantum wells grown, via molecular-beam epitaxy (MBE), under identical growth conditions, (ii) Monte Carlo simulations of MBE growth, and (iii) comparison of the results of (i) with a new theory of PL linewidths based upon the nature of interfaces suggested by (ii). The measured behavior, Γ~dw-1, for dw in the range of 5 monolayers (ML) to 40 ML investigated is in contradiction to the widely used notion of fluctuations in the well width and demands a new physical model. The growth-kinetics-dependent in-plane Al concentration fluctuations at and near the interfaces revealed by the simulations of MBE growth indicate that band-edge discontinuity fluctuations and short-ranged alloy disorder are likely to be the dominant scattering mechanisms in high-quality quantum-well structures. Thus, a new theory of PL linewidth, based upon (a) short-ranged alloy-disorder scattering potential defined in the usual terms of difference of atomic potentials and (b) fluctuations in band-edge discontinuity over the size of the exciton, is introduced and the variance of these perturbations is calculated over a suitably chosen exciton wave function. The calculated dependence of Γ on dw is found to be in good agreement with the observed ~dw-1 behavior. The much used but hardly ever specified term "interface roughness" is thus demonstrated for the first time to correspond to fluctuations in the crystal potential of alloy-disorder type and band-edge discontinuity fluctuations, rather than the commonly used notion and model of well-width fluctuations