A legal version of the Nanoworld

Article à paraître dans le numéro spécial "Nanotechnologies" des comptes-rendus de l'académie des sciences 2011Nanosciences and nanotechnologies come into a pre-existing legal system. Their arrival, and how they are received are worthy of analysis. Such an effort shall at first include simply lexical considerations, in order to penetrate, via their origins, the traces of these specific objects into the territory of law. The goal of this article is to explore the effects of "nanos" in various legal fields, including their relevance to the principle of precaution, patent law, and the applicable laws for chemical substances

La version juridique du nanomonde

article à paraître dans le numéro spécial des Comptes-rendus de l'académie des Sciences 2011 sur les NanotechnologiesLes nanosciences et nanotechnologies viennent s'inscrire dans un système juridique préexistant. Les modalités de leur réception par le droit méritent d'être analysées. Pour mener à bien cet exercice, il convient, après avoir exclu la piste d'une recherche purement lexicale, d'explorer quelques-unes des traces que l'émergence de ces objets spécifiques laisse dans le territoire du droit. C'est ce que tente de faire cet article, en se penchant sur l'effet des " nanos " dans différents champs juridiques, allant du principe de précaution jusqu'au droit des brevets d'invention en passant par le droit applicable aux substances chimiques

Analyses des consommations énergétiques des tracteurs en usage réel : application aux chantiers d'épandage

Afin de réduire la facture énergétique de l'agriculture, il faut pouvoir améliorer l'efficacité des machines utilisées, mais aussi celle des méthodes de productions agricoles. À partir d'une campagne d'expérimentations sur le travail d'épandage, les auteurs nous montrent ici comment produire des indicateurs pertinents pour évaluer la performance énergétique d'une opération agricole

Active force generation contributes to the complexity of spontaneous activity and to the response to stretch of murine cardiomyocyte cultures.

Monolayer cultures of cardiac cells exhibit spontaneous electrical and contractile activity, as in a natural cardiac pacemaker. Beating variability in these preparations recapitulates the power-law behavior of heart rate variability in vivo. However, the effects of mechano-electrical feedback on beating variability are not yet fully understood. Using stretchable microelectrode arrays, we examined the effects of the contraction uncoupler blebbistatin and the non-specific stretch activated channel blocker streptomycin on beating variability and on stretch-induced changes of beat rate. Without stretch, blebbistatin decreased the spatial complexity of beating variability, while streptomycin had no effects. Both stretch and release transiently increased beat rate; blebbistatin attenuated the increase of beat rate upon stretch, while streptomycin had no effects. Active force generation contributes to the complexity of spatiotemporal patterns of beating variability and to the increase of beat rate upon mechanical deformation. Our study contributes to understanding how mechano-electric feedback influences heart rate variability. Cardiomyocyte cultures exhibit spontaneous electrical and contractile activity, as in a natural cardiac pacemaker. In such preparations, beat rate variability exhibits features similar to those of heart rate variability in vivo. Mechanical deformations and forces feedback on the electrical properties of cardiomyocytes, but it is not fully elucidated how this mechano-electrical interplay affects beating variability in such preparations. Using stretchable microelectrode arrays, we assessed the effects of the myosin inhibitor blebbistatin and the nonselective stretch-activated channel blocker streptomycin on beating variability and on the response of neonatal or foetal murine ventricular cell cultures against deformation. Spontaneous electrical activity was recorded without stretch and upon predefined deformation protocols (5% uniaxial and 2% equibiaxial strain, applied repeatedly for 1 min every 3 min). Without stretch, spontaneous activity originated from the edge of the preparations, and its site of origin switched frequently in a complex manner across the cultures. Blebbistatin did not change mean beat rate, but it decreased the spatial complexity of spontaneous activity. In contrast, streptomycin did not exert any manifest effects. During the deformation protocols, beat rate transiently increased upon stretch, but paradoxically also upon release. Blebbistatin attenuated the response to stretch, while this response was not affected by streptomycin. Therefore, our data support the notion that in a spontaneously firing network of cardiomyocytes, active force generation, rather than stretch-activated channels, is mechanistically involved in the complexity of the spatiotemporal patterns of spontaneous activity and in the stretch-induced acceleration of beating. Abstract figure legend Mechano-electric feedback modulates myocardial electrical function, including pacemaking. By growing monolayer cultures of spontaneously active murine cardiac cells on stretchable microelectrode arrays, we examined whether active contractions influence the spatiotemporal characteristics of beating variability and the effects of stretching on beat rate. Under control conditions (no stretch and no pharmacological agent), the origin of the electrical activity changed frequently. After blocking contractions with blebbistatin, the spatiotemporal pattern of electrical activity became less variable and less complex. Under control conditions (no pharmacological agent), stretching (and also releasing) the cardiomyocyte monolayers transiently increased beat rate. Blebbistatin attenuated the acceleration of beating upon stretch. In contrast, streptomycin had no detectable effects. Thus, active force generation is involved in determining beating variability in spontaneously active cardiac tissue. Possible mechanisms may include cellular processes that sense contraction and chemical messengers. Our study contributes to understanding how mechano-electric feedback influences heart rate variability. This article is protected by copyright. All rights reserved

Analyses des consommations énergétiques des tracteurs en usage réel : application aux chantiers d'épandage

National audienceAfin de réduire la facture énergétique de l'agriculture, il faut pouvoir améliorer l'efficacité des machines utilisées, mais aussi celle des méthodes de productions agricoles. À partir d'une campagne d'expérimentations sur le travail d'épandage, les auteurs nous montrent ici comment produire des indicateurs pertinents pour évaluer la performance énergétique d'une opération agricole

A finite element model of the mechanical interactions between peripheral nerves and intrafascicular implants

: Objective.Intrafascicular peripheral nerve implants are key components in the development of bidirectional neuroprostheses such as touch-enabled bionic limbs for amputees. However, the durability of such interfaces is hindered by the immune response following the implantation. Among the causes linked to such reaction, the mechanical mismatch between host nerve and implant is thought to play a decisive role, especially in chronic settings.Approach.Here we focus on modeling mechanical stresses induced on the peripheral nerve by the implant's micromotion using finite element analysis. Through multiple parametric sweeps, we analyze the role of the implant's material, geometry (aspect-ratio and shape), and surface coating, deriving a set of parameters for the design of better-integrated implants.Main results.Our results indicate that peripheral nerve implants should be designed and manufactured with smooth edges, using materials at most three orders of magnitude stiffer than the nerve, and with innovative geometries to redistribute micromotion-associated loads to less delicate parts of the nerve such as the epineurium.Significance.Overall, our model is a useful tool for the peripheral nerve implant designer that is mindful of the importance of implant mechanics for long term applications

Materials and technologies for soft implantable neuroprostheses

Implantable neuroprostheses are engineered systems designed to restore or substitute function for individuals with neurological deficits or disabilities. These systems involve at least one uni-or bidirectional interface between a living neural tissue and a synthetic structure, through which information in the form of electrons, ions or photons flows. Despite a few notable exceptions, the clinical dissemination of implantable neuroprostheses remains limited, because many implants display inconsistent long-term stability and performance, and are ultimately rejected by the body. Intensive research is currently being conducted to untangle the complex interplay of failure mechanisms. In this Review, we emphasize the importance of minimizing the physical and mechanical mismatch between neural tissues and implantable interfaces. We explore possible materials solutions to design and manufacture neurointegrated prostheses, and outline their immense therapeutic potential

Can procalcitonin measurement help the diagnosis of osteomyelitis and septic arthritis? A prospective trial

<p>Abstract</p> <p>Objectives</p> <p>Procalcitonin (PCT) is an accurate marker for differentiating bacterial infection from non-infective causes of inflammation or viral infection. However, there is only one study in children which tested procalcitonin as a diagnostic aid in skeletal infections. With this study we sought to evaluate the sensitivity, specificity and predictive values of procalcitonin for identifying bone and joint infection in children evaluated in the emergency department for non traumatic decreased active motion of a skeletal segment.</p> <p>Methods</p> <p>Patients aged 1 month to 14 years were prospectively included in the emergency department when suspected for osteomyelitis or septic arthritis. Procalcitonin levels, C reactiv protein, white blood cell count were measured and bacteriological samples were collected before initiation of antibiotic treatment. Patients were assigned to 3 groups according to the degree of suspected infection: group 1 confirmed infection, group 2 presumed infection and group 3 non infected patients.</p> <p>Results</p> <p>Three hundred thirty nine patients were included (118 girls and 221 boys). Group 1 comprised 8 patients (2 had PCT levels > 0.5 ng/ml). Two had osteomyelitis and 6 septic arthritis. Forty children were incuded in group 2 (4 had PCT levels > 0.5 ng/ml). Eighteen had presumed osteomyelitis and 22 presumed septic arthritis. Group 3 comprised 291 children (9 PCT levels > 0.5 ng/ml) who recovered without antibiotic treatment. The specificity of the PCT as a marker of bacterial infection (comparing Group 1 and Group 3) was 96.9% [95% CI, 94.2-98.6], the sensitivity 25% [95% CI, 3.2-65.1], the positive predictive value (PPV) 18.2% [95% CI, 2.3-51.8] and the negative predictive value (NPV) 97.9% [95% CI, 95.5-99.2].</p> <p>Conclusion</p> <p>PCT is not a good screening test for identifying skeletal infection in children. Larger studies are needed to evaluate still more the place of PCT measurements in the diagnosis of osteomyelitis and septic arthritis.</p

Soft metal constructs for large strain sensor membrane

Thin gold films on silicone display large reversible change in electrical resistance upon stretching. Eutectic liquid metal conductors maintain bulk metal conductivity, even upon extensive elongation. When integrated together, the soft metals enable multidirectional, large strain sensor skin. Their fabrication process combines thermal evaporation of thin gold film patterns through stencil mask with microplotting of eutectic gallium indium microwires, and packaging in silicone rubber. Using three-element rectangular rosettes, we demonstrate a sensor skin that can reliably and locally quantify the plane strain vector in surfaces subject to stretch (up to 50% strain) and indentation. This hybrid technology will find applications in soft robotics, prosthetics and wearable health monitoring systems