How Geometry Controls the Tearing of Adhesive Thin Films on Curved Surfaces

Flaps can be detached from a thin film glued on a solid substrate by tearing and peeling. For flat substrates, it has been shown that these flaps spontaneously narrow and collapse in pointy triangular shapes. Here we show that various shapes, triangular, elliptic, acuminate or spatulate, can be observed for the tears by adjusting the curvature of the substrate. From combined experiments and theoretical models, we show that the flap morphology is governed by simple geometric rules.Comment: 6 pages, 5 figure

Effect of the elongation rate on the biodegradation of oriented polycaprolactone films by a pure strain of micro-organisms isolated from an industrial compost for house-hold refuse

It has been demonstrated that unidirectional orientation of semi-crystalline polycaprolactone (PCL) films strongly affects their degradation behaviour in the presence of micro-organisms. For films of the same final thickness (300 μm), elongated using strain rates between 1.6 and 0.02 min-1, the rate of oxygen consumption is similar for all samples during the first 200 h of degradation. After that time the rate becomes strongly dependent on the elongation conditions. After 700 h of incubation, the weight loss is 99 and 25% for samples obtained with strain rates of 1.6 and 0.02 min-1 respectively. When compared with the non-orientated sample, the 1.6 min-1 sample degrades faster while the others degrade more slowly. The results are discussed in terms of models proposed in the literature for oriented films. © Wiley-VCH Verlag GmbH, 1999.SCOPUS: ar.jFLWINinfo:eu-repo/semantics/publishe

Range Estimation of Floating-Point Variables in Simulink Models

International audienceThe transformation of floating-point programs into fixed-point equivalent programs is a challenge because the behaviors of these arithmetics are different. Generally, this transformation is facilitated thanks to a two steps analysis of the design. The first step consists in inferring the range of values for each variables. The second step is the analysis of the precision of the computations taking into account the rounding-errors. In our talk, we will present a new statistical method for inferring dynamic range of floating-point variables in Simulink models. Our approach is based on the extreme value theory. Experimental results will also be presented

Synthesis and thermal characterization of crystallizable poly(caprolactone)/poly(hexamethylene terephthalate) block copolymer

An alternating multiblock copolymer of poly(ε-caprolactone) (PCL) and poly(hexamethylene terephthalate) (PHT) with a 48/52 PCL/PHT composition weight ratio has been synthesized. Its structural and morphological parameters were measured using 1H NMR, density measurements, differential scanning calorimetry and its crystallization and melting were studied by real time simultaneous WAXS and SAXS using synchrotron radiation. These results are compared with those for the pure PCL and PHT used as building blocks. In the crystallization conditions used here, the copolymer crystallizes as alternate lamellae of PHT and PCL. The crystallinity of the PCL blocks is much lower than that of pure PCL because they crystallize under stress in the semi-crystalline PHT network. © 2001 Elsevier Science Ltd. All rights reserved.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Mise au point d'un appareil de faisceaux moleculaires supersoniques Etudes des transformations en couches minces d'un metal sur la surface d'un autre par la diffusion d'atomes d'helium

Available at INIST (FR), Document Supply Service, under shelf-number : AR 13881 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc

Long term anti-SARS-CoV-2 antibody kinetics and correlate of protection against Omicron BA.1/BA.2 infection

Binding antibody levels against SARS-CoV-2 have shown to be correlates of protection against infection with pre-Omicron lineages. This has been challenged by the emergence of immune-evasive variants, notably the Omicron sublineages, in an evolving immune landscape with high levels of cumulative incidence and vaccination coverage. This in turn limits the use of widely available commercial high-throughput methods to quantify binding antibodies as a tool to monitor protection at the population-level. Here we show that anti-Spike RBD antibody levels, as quantified by the immunoassay used in this study, are an indirect correlate of protection against Omicron BA.1/BA.2 for individuals previously infected by SARS-CoV-2. Leveraging repeated serological measurements between April 2020 and December 2021 on 1083 participants of a population-based cohort in Geneva, Switzerland, and using antibody kinetic modeling, we found up to a three-fold reduction in the hazard of having a documented positive SARS-CoV-2 infection during the Omicron BA.1/BA.2 wave for anti-S antibody levels above 800 IU/mL (HR 0.30, 95% CI 0.22-0.41). However, we did not detect a reduction in hazard among uninfected participants. These results provide reassuring insights into the continued interpretation of SARS-CoV-2 binding antibody measurements as an independent marker of protection at both the individual and population levels

Seroprevalence of anti-SARS-CoV-2 antibodies and cross-variant neutralization capacity after the Omicron BA.2 wave in Geneva, Switzerland: a population-based study.

More than two years into the COVID-19 pandemic, most of the population has developed anti-SARS-CoV-2 antibodies from infection and/or vaccination. However, public health decision-making is hindered by the lack of up-to-date and precise characterization of the immune landscape in the population. Here, we estimated anti-SARS-CoV-2 antibodies seroprevalence and cross-variant neutralization capacity after Omicron became dominant in Geneva, Switzerland. We conducted a population-based serosurvey between April 29 and June 9, 2022, recruiting children and adults of all ages from age-stratified random samples of the general population of Geneva, Switzerland. We tested for anti-SARS-CoV-2 antibodies using commercial immunoassays targeting either the spike (S) or nucleocapsid (N) protein, and for antibody neutralization capacity against different SARS-CoV-2 variants using a cell-free Spike trimer-ACE2 binding-based surrogate neutralization assay. We estimated seroprevalence and neutralization capacity using a Bayesian modeling framework accounting for the demographics, vaccination, and infection statuses of the Geneva population. Among the 2521 individuals included in the analysis, the estimated total antibodies seroprevalence was 93.8% (95% CrI 93.1-94.5), including 72.4% (70.0-74.7) for infection-induced antibodies. Estimates of neutralizing antibodies in a representative subsample (N = 1160) ranged from 79.5% (77.1-81.8) against the Alpha variant to 46.7% (43.0-50.4) against the Omicron BA.4/BA.5 subvariants. Despite having high seroprevalence of infection-induced antibodies (76.7% [69.7-83.0] for ages 0-5 years, 90.5% [86.5-94.1] for ages 6-11 years), children aged <12 years had substantially lower neutralizing activity than older participants, particularly against Omicron subvariants. Overall, vaccination was associated with higher neutralizing activity against pre-Omicron variants. Vaccine booster alongside recent infection was associated with higher neutralizing activity against Omicron subvariants. While most of the Geneva population has developed anti-SARS-CoV-2 antibodies through vaccination and/or infection, less than half has neutralizing activity against the currently circulating Omicron BA.5 subvariant. Hybrid immunity obtained through booster vaccination and infection confers the greatest neutralization capacity, including against Omicron. General Directorate of Health in Geneva canton, Private Foundation of the Geneva University Hospitals, European Commission ("CoVICIS" grant), and a private foundation advised by CARIGEST SA