Effective interactions between inclusions in complex fluids driven out of equilibrium

The concept of fluctuation-induced effective interactions is extended to systems driven out of equilibrium. We compute the forces experienced by macroscopic objects immersed in a soft material driven by external shaking sources. We show that, in contrast with equilibrium Casimir forces induced by thermal fluctuations, their sign, range and amplitude depends on specifics of the shaking and can thus be tuned. We also comment upon the dispersion of these shaking-induced forces, and discuss their potential application to phase ordering in soft-materials.Comment: 10 pages, 8 figures, to appear in PR

Colloquium: Mechanical formalisms for tissue dynamics

The understanding of morphogenesis in living organisms has been renewed by tremendous progressin experimental techniques that provide access to cell-scale, quantitative information both on theshapes of cells within tissues and on the genes being expressed. This information suggests that ourunderstanding of the respective contributions of gene expression and mechanics, and of their crucialentanglement, will soon leap forward. Biomechanics increasingly benefits from models, which assistthe design and interpretation of experiments, point out the main ingredients and assumptions, andultimately lead to predictions. The newly accessible local information thus calls for a reflectionon how to select suitable classes of mechanical models. We review both mechanical ingredientssuggested by the current knowledge of tissue behaviour, and modelling methods that can helpgenerate a rheological diagram or a constitutive equation. We distinguish cell scale ("intra-cell")and tissue scale ("inter-cell") contributions. We recall the mathematical framework developpedfor continuum materials and explain how to transform a constitutive equation into a set of partialdifferential equations amenable to numerical resolution. We show that when plastic behaviour isrelevant, the dissipation function formalism appears appropriate to generate constitutive equations;its variational nature facilitates numerical implementation, and we discuss adaptations needed in thecase of large deformations. The present article gathers theoretical methods that can readily enhancethe significance of the data to be extracted from recent or future high throughput biomechanicalexperiments.Comment: 33 pages, 20 figures. This version (26 Sept. 2015) contains a few corrections to the published version, all in Appendix D.2 devoted to large deformation

Behavioural and Developmental Interventions for Autism Spectrum Disorder: A Clinical Systematic Review

Background: Much controversy exists regarding the clinical efficacy of behavioural and developmental interventions for improving the core symptoms of autism spectrum disorders (ASD). We conducted a systematic review to summarize the evidence on the effectiveness of behavioural and developmental interventions for ASD. Methods and Findings: Comprehensive searches were conducted in 22 electronic databases through May 2007. Further information was obtained through hand searching journals, searching reference lists, databases of theses and dissertations, and contacting experts in the field. Experimental and observational analytic studies were included if they were written in English and reported the efficacy of any behavioural or developmental intervention for individuals with ASD. Two independent reviewers made the final study selection, extracted data, and reached consensus on study quality. Results were summarized descriptively and, where possible, meta-analyses of the study results were conducted. One-hundred-and-one studies at predominantly high risk of bias that reported inconsistent results across various interventions were included in the review. Meta-analyses of three controlled clinical trials showed that Lovaas treatment was superior to special education on measures of adaptive behaviour, communication and interaction, comprehensive language, daily living skills, expressive language, overall intellectual functioning and socialization. High-intensity Lovaas was superior to low-intensity Lovaas on measures of intellectual functioning in two retrospective cohort studies. Pooling the results of two randomized controlle

Progressive Parkinsonism by acute dysfunction of excitatory amino acid transporters in the rat substantia nigra

International audienceParkinson's disease (PD) is characterized by the progressive degeneration of substantia nigra (SN) dopamine neurons, involving a multifactorial cascade of pathogenic events. Here we explored the hypothesis that dysfunction of excitatory amino acid transporters (EAATs) might be involved. Acutely-induced dysfunction of EAATs in the rat SN, by single unilateral injection of their substrate inhibitor l-trans-pyrrolidine-2,4-dicarboxylate (PDC), triggers a neurodegenerative process mimicking several PD features. Dopamine neurons are selectively affected, consistent with their sustained excitation by PDC measured by slice electrophysiology. The anti-oxidant N-acetylcysteine and the NMDA receptor antagonists ifenprodil and memantine provide neuroprotection. Besides oxidative stress and NMDA receptor-mediated excitotoxicity, glutathione depletion and neuroinflammation characterize the primary insult. Most interestingly, the degeneration progresses overtime with unilateral to bilateral and caudo-rostral evolution. Transient adaptive changes in dopamine function markers in SN and striatum accompany cell loss and axonal dystrophy, respectively. Motor deficits appear when neuron loss exceeds 50% in the most affected SN and striatal dopamine tone is dramatically reduced. These findings outline a functional link between EAAT dysfunction and several PD pathogenic mechanisms/pathological hallmarks, and provide a novel acutely-triggered model of progressive Parkinsonism

Affinity-Purified Respiratory Syncytial Virus Antibodies from Intravenous Immunoglobulin Exert Potent Antibody-Dependent Cellular Cytotoxicity

Mixed infections are one of the major therapeutic challenges, as the current strategies have had limited success. One of the most common and widespread conditions of mixed infection is respiratory syncytial virus-mediated pathology of the respiratory tract in children. There is a dire need for the development of novel therapeutic approaches during mixed infections. Therapeutic intravenous immunoglobulin preparations, obtained from plasma pools of healthy donors have been used in immune deficiencies. This study was thus designed to characterize the functional efficacy of RSV-specific antibodies in IVIg. To explore the functional ability of these affinity-purified RSV-specific antibodies, the antibody-dependent and complement dependent cytotoxicity was determined using peripheral cells of healthy donors. This study demonstrates the existence of highly potent RSV-specific antibodies in IVIg preparations and provides the basis for the use of IVIg as broad-spectrum protective shield to RSV-infected children during mixed infections