William Lang Dessaint (1930-2013)

William Dessaint est né le 6 mars 1930 à Villerupt (Meurthe-et-Moselle) d’un père français et d’une mère américaine. À la fin de la Seconde Guerre mondiale et à la suite de la séparation de ses parents, il quitta la France pour les États-Unis avec sa mère et son frère cadet. Au hasard de ses amitiés et du fait de l’éducation biculturelle qu’il avait reçue, il se découvrit une passion pour l’étude de la géographie et des peuples du monde, et notamment pour l’Europe balkanique et l’Asie. Il s’e..

The differentiability of the drag with respect to the variations of a Lipschitz domain in a Navier-Stokes flow

This paper is concerned with the computation of the drag T associated with a body traveling at uniform velocity in a fluid governed by the stationary Navier–Stokes equations. It is assumed that the fluid fills a domain of the form Ω+u, where Ω ⊂ R3 is a reference domain and u is a displacement field. We assume only that Ω is a Lipschitz domain and that u is Lipschitz-continuous. We prove that, at least when the velocity of the body is sufficiently small, u 7→ T(Ω + u) is a C∞ mapping (in a ball centered at 0). We also compute the derivative at 0.Dirección General de Investigación Científica y Tecnológic

Décomposition et analyse du signal stabilométrique

L'étude du signal stabilométrique est une étape incontournable lors de la modélisation des mécanismes intervenant dans l'équilibre chez l'Homme. Nous considérons ce signal comme issu d'un système dynamique composé de sous-systèmes dynamiques différents. En utilisant des caractéristiques temporelle (τe) et dimensionnelle (De), nous proposons une décomposition du signal stabilométrique en trois signaux (tendance, excursion, tremblements). S'en suit une analyse du signal présentant la structure la plus complexe: les tremblements

Fracture behaviour of a Fe–22Mn–0.6C–0.2V austenitic TWIP steel

International audienceThe mechanical behaviour of a 22Mn-0.6C-0.2V austenitic TWIP steel has been extensively characterised for a variety of strain ratios (from shear to biaxial stretching) using smooth and notched specimens. A constitutive model involving a non-isotropic yield function together with isotropic and/or kinematic hardening satisfactorily represented the experimental database. It was used to estimate local stress and strain fields and to derive a fracture criterion based on the equivalent stress and Lode angle that were expressed to be consistent with the constitutive equations describing the plastic flow behaviour. A weak dependence on hydrostatic stress further improves prediction of fracture initiation, with an average standard error of less than 5% over ten different mechanical tests

Nano-Engineered Scaffold for Osteoarticular Regenerative Medicine

In the last decade, regenerative medicine has benefited from the exponential development of nanomaterial sciences, tissue engineering and cell-based therapies. More and more sophisticated designed structures and surface topologies are being developed to basically mimic the extracellular matrix of native tissues such as cartilage and bone. Here we give an overview of the progress made in osteochondral lesion repair, with nano-engineered scaffolds comprising building blocks such as nanoparticles, nanotubes, layer-by-layer nano-assemblies, molecular self-assembly, nanopatterned surfaces…. This nano-engineering technology is coupled with bio-functionalization, by the use of adhesion peptides, growth factors, or deoxyribonucleic acid, to drive cell adhesion, proliferation and behavior towards tissue regeneration. In osteochondral regeneration, the challenge is the simultaneous development of chondrocytes and cartilage extracellular matrix on the one side and a well vascularized bone tissue with osteoblasts on the other sid

High-throughput malaria serosurveillance using a one-step multiplex bead assay.

BACKGROUND: Serological data indicating the presence and level of antibodies against infectious disease antigens provides indicators of exposure and transmission patterns in a population. Laboratory testing for large-scale serosurveys is often hindered by time-consuming immunoassays that employ multiple tandem steps. Some nations have recently begun using malaria serosurveillance data to make inferences about the malaria exposure in their populations, and serosurveys have grown increasingly larger as more accurate estimates are desired. Presented here is a novel approach of antibody detection using bead-based immunoassay that involves incubating all assay reagents concurrently overnight. RESULTS: A serosurvey in was performed in Haiti in early 2017 with both sera (n = 712) and dried blood spots (DBS, n = 796) collected for the same participants. The Luminex® multiplex bead-based assay (MBA) was used to detect total IgG against 8 malaria antigens: PfMSP1, PvMSP1, PmMSP1, PfCSP, PfAMA1, PfLSA1, PfGLURP-R0, PfHRP2. All sera and DBS samples were assayed by MBA using a standard immunoassay protocol with multiple steps, as well a protocol where sample and all reagents were incubated together overnight-termed here the OneStep assay. When compared to a standard multi-step assay, this OneStep assay amplified the assay signal for IgG detection for all 8 malaria antigens. The greatest increases in assay signal were seen at the low- and mid-range IgG titers and were indicative of an enhancement in the analyte detection, not simply an increase in the background signal of the assay. Seroprevalence estimates were generally similar for this sample Haitian population for all antigens regardless of serum or DBS sample type or assay protocol used. CONCLUSIONS: When using the MBA for IgG detection, overnight incubation for the test sample and all assay reagents greatly minimized hands-on time for laboratory staff. Enhanced IgG signal was observed with the OneStep assay for all 8 malaria antigens employed in this study, and seroprevalence estimates for this sample population were similar regardless of assay protocol used. This overnight incubation protocol has the potential to be deployed for large-scale malaria serosurveys for the high-throughput and timely collection of antibody data, particularly for malaria seroprevalence estimates

Quality control of multiplex antibody detection in samples from large-scale surveys: the example of malaria in Haiti.

Measuring antimalarial antibodies can estimate transmission in a population. To compare outputs, standardized laboratory testing is required. Here we describe the in-country establishment and quality control (QC) of a multiplex bead assay (MBA) for three sero-surveys in Haiti. Total IgG data against 21 antigens were collected for 32,758 participants. Titration curves of hyperimmune sera were included on assay plates, assay signals underwent 5-parameter regression, and inspection of the median and interquartile range (IQR) for the y-inflection point was used to determine assay precision. The medians and IQRs were similar for Surveys 1 and 2 for most antigens, while the IQRs increased for some antigens in Survey 3. Levey-Jennings charts for selected antigens provided a pass/fail criterion for each assay plate and, of 387 assay plates, 13 (3.4%) were repeated. Individual samples failed if IgG binding to the generic glutathione-S-transferase protein was observed, with 659 (2.0%) samples failing. An additional 455 (1.4%) observations failed due to low bead numbers (<20/analyte). The final dataset included 609,438 anti-malaria IgG data points from 32,099 participants; 96.6% of all potential data points if no QC failures had occurred. The MBA can be deployed with high-throughput data collection and low inter-plate variability while ensuring data quality