The essential role of surface pinning in the dynamics of charge density waves submitted to external dc fields

A Charge Density Wave (CDW) submitted to an electric field displays a strong shear deformation because of pinning at the lateral surfaces of the sample. This CDW transverse pinning was recently observed but has received little attention from a theoretical point of view until now despite important consequences on electrical conductivity properties. Here, we provide a description of this phenomenon by considering a CDW submitted to an external dc electric field and constrained by boundary conditions including both longitudinal pinning due to electrical contacts and transverse surface pinning. A simple formula for the CDW phase is obtained in 3D by using the Green function and image charges method. In addition, an analytical expression of the threshold field dependence on both length and sample cross section is obtained by considering the phase slip process. We show that the experimental data are well reproduced with this model and that bulk pinning can be neglected. This study shows that the dynamical properties of CDW systems could be mainly driven by boundary effects, despite the comparatively huge sample volumes.Comment: 7 pages of main text, 7 pages of appendices 15 figure

Reply to: Ultrafast evolution and transient phases of a prototype out-of-equilibrium Mott-Hubbard material

International audienceReplying to D. Moreno-Mencía et al. Nature Communicationshttps://doi.org/10.1038/s41467-019-11743-3 (2019)

Longitudinal anatomical response of retinal-choroidal anastomosis to anti-vascular endothelial growth factor therapy.

Abstract PURPOSE: To evaluate the longitudinal anatomical response of retinal-choroidal anastomosis (RCA) to intravitreal ranibizumab injection using spectral-domain optical coherence tomography (SD-OCT). METHODS: We reviewed the medical records of 21 consecutive patients with RCA who underwent intravitreal ranibizumab injections at the University Eye Clinic of Creteil between January 2009 and June 2010. The SD-OCT features at baseline, at 3 months, and at 12 months were retrospectively analyzed. Based on SD-OCT, RCAs were classified as showing a focal retinal pigment epithelium (RPE) erosion ("erosion sign") over a small, localized RPE elevation; a focal RPE break leaving two free RPE flaps ("flap sign") at the level of a small, localized RPE elevation; or a large convex RPE prominence and a focal funnel-shaped RPE kissing an inverted focal funnel-shaped inner neuroepithelium ("kissing sign"). RESULTS: Twenty-one eyes of 21 patients (3 men and 18 women, aged 81.6 ± 6.8 years) diagnosed with RCA naive to any treatment were included for analysis. Spearman ρ correlation between best-corrected visual acuity and lesion classification was 0.54 (P = 0.01) at Month 3 and 0.85 (P < 0.001) at Month 12. Eyes showing the flap sign at baseline underwent significantly less ranibizumab injections after the loading phase (2.14 ± 0.89 vs. 3.40 ± 0.96, P = 0.007) and showed a greater improvement in best-corrected visual acuity at Month 12 (from 0.52 ± 0.14 to 0.38 ± 0.15, P = 0.03) compared with eyes showing the kissing sign. At 12 months, 3 of 10 eyes with flap sign at baseline showed RCA activity, whereas 7 of 10 regressed to erosion sign phase. Of the 10 eyes with kissing sign at baseline, 6 progressed to a fibroglial scar. CONCLUSION: A flap sign of RCA at baseline seems a favorable prognostic factor as concerns best-corrected visual acuity improvement and the need for retreatment

Consensus d’experts français sur les critères de choix d’un traitement de 1(re) intention dans la DMLA néovasculaire et importance du ratio bénéfice/risque à long terme

Le choix d’un traitement de 1re intention pour optimiser les résultats à long terme est un enjeu majeur de la prise en charge des patients atteints de DMLA néovasculaire. Dans un contexte actuel de molécules en développement est apparue la nécessité d’identifier les critères indispensables à prendre en compte lors de la mise en place d’un traitement chez un patient naïf atteint de DMLA néovasculaire afin de garantir un rapport bénéfice/risque optimal à long terme. Cet article propose un consensus établi selon la méthodologie de type Delphi (en intégrant une gradation dans les consensus en fonction de l’analyse du taux de convergence des réponses) qui pourrait constituer une aide pour les ophtalmologistes pour l’initiation et le suivi du traitement des patients atteints de DMLA néovasculaire. Quatorze questions ont été soumises à un panel de 93 experts rétinologues français. Treize questions (93 %) ont obtenu un consensus (≥ 50 % de réponses consensuelles). Les experts recommandent ainsi de prendre en compte en priorité l’efficacité et la rapidité d’action respectives des molécules, leur sécurité d’utilisation ainsi que leur capacité d’espacement des injections. Le critère d’efficacité attendu en priorité d’une molécule est la combinaison de l’amélioration de l’acuité visuelle et de l’assèchement des fluides. En matière de sécurité d’utilisation, les experts recommandent une surveillance supplémentaire pour les molécules actuellement en développement, et ce à toutes les visites programmées, visant à détecter précocement d’éventuels effets indésirables tels que l’inflammation intraoculaire et accordent une place importante au conditionnement de la molécule. La capacité d’espacement des injections est importante à prendre en compte et il est recommandé d’atteindre un intervalle maximal compris entre 12 et 16 semaines. La stabilité de l’intervalle maximal atteinte par les patients est également un critère de choix important.Choosing a first-line treatment to optimize long-term outcomes is a major challenge for treating patients with neovascular age-related macular degeneration (AMD). The development of several new molecules makes it critical to identify the relevant factors to consider so as to provide an optimal risk-benefit ratio when initiating a treatment in naïve patients with neovascular AMD. This paper proposes a consensus established with the Delphi method (which includes a gradation in a consensus based on an analysis of the convergence rate of answers) to provide criteria that guide the ophthalmologist's decision for treatment initiation and follow-up in neovascular AMD patients. Fourteen questions were submitted to 93 French retina experts. Thirteen (93%) of the questions reached a consensus (≥50% of answers consensual). The criteria recommended to take into account were both efficacy and onset of action of the molecules, their safety, and the ability to decrease injection frequency. The primary criterion of expected efficacy of a molecule is a combination of the gain in visual acuity and resorption of retinal fluid. With regard to safety, experts recommend tighter follow-up for molecules currently in development, and at every scheduled visit, patients should be screened to identify early any potential adverse effects such as intraocular inflammation, retinal vasculitis or vascular occlusion. Experts also emphasize the importance of the packaging of the biological, with a preference toward prefilled syringes. Injection frequency is a key factor, and the authors recommended aiming for a maximal injection interval of 12 to 16 weeks. The stability of that maximum interval is also an important factor to consider in treatment selection

Core Loss During a Severe Accident (COLOSS)

The core loss during a severe accident (COLOSS) project was a 3-year shared-cost action, which started in February 2000. The project is concerned with the consequences that core degradation, occurring under severe accident conditions, may have on H2 production, melt generation and the source term. Unresolved in-vessel risk-relevant issues are studied, through a large number of experiments such as UO2 and MOX dissolution by molten zircaloy and burn-up effects, simultaneous dissolution of UO2 and ZrO2 in rod geometry, oxidation of U-O-Zr mixtures, oxidation of pure B4C material and degradation and oxidation of B4C control rods. SA computer codes are used for plant calculations to assess SA code capabilities and to apply results produced in this project to evaluate their consequences on key SA sequences occurring in different plants such as PWR-1300, BWR, VVER-1000, EPR and in the TMI-2 accident.JRC.F.4-Nuclear design safet