A Glucose BioFuel Cell Implanted in Rats

Powering future generations of implanted medical devices will require cumbersome transcutaneous energy transfer or harvesting energy from the human body. No functional solution that harvests power from the body is currently available, despite attempts to use the Seebeck thermoelectric effect, vibrations or body movements. Glucose fuel cells appear more promising, since they produce electrical energy from glucose and dioxygen, two substrates present in physiological fluids. The most powerful ones, Glucose BioFuel Cells (GBFCs), are based on enzymes electrically wired by redox mediators. However, GBFCs cannot be implanted in animals, mainly because the enzymes they rely on either require low pH or are inhibited by chloride or urate anions, present in the Extra Cellular Fluid (ECF). Here we present the first functional implantable GBFC, working in the retroperitoneal space of freely moving rats. The breakthrough relies on the design of a new family of GBFCs, characterized by an innovative and simple mechanical confinement of various enzymes and redox mediators: enzymes are no longer covalently bound to the surface of the electron collectors, which enables use of a wide variety of enzymes and redox mediators, augments the quantity of active enzymes, and simplifies GBFC construction. Our most efficient GBFC was based on composite graphite discs containing glucose oxidase and ubiquinone at the anode, polyphenol oxidase (PPO) and quinone at the cathode. PPO reduces dioxygen into water, at pH 7 and in the presence of chloride ions and urates at physiological concentrations. This GBFC, with electrodes of 0.133 mL, produced a peak specific power of 24.4 µW mL−1, which is better than pacemakers' requirements and paves the way for the development of a new generation of implantable artificial organs, covering a wide range of medical applications

National Accounts ESA. Aggregates 1970-1975. 1976

<p>Model 3 multiple logistic regression analysis for burnout diagnosis.</p

Simulation of Postsynaptic Glutamate Receptors Reveals Critical Features of Glutamatergic Transmission

Activation of several subtypes of glutamate receptors contributes to changes in postsynaptic calcium concentration at hippocampal synapses, resulting in various types of changes in synaptic strength. Thus, while activation of NMDA receptors has been shown to be critical for long-term potentiation (LTP) and long term depression (LTD) of synaptic transmission, activation of metabotropic glutamate receptors (mGluRs) has been linked to either LTP or LTD. While it is generally admitted that dynamic changes in postsynaptic calcium concentration represent the critical elements to determine the direction and amplitude of the changes in synaptic strength, it has been difficult to quantitatively estimate the relative contribution of the different types of glutamate receptors to these changes under different experimental conditions. Here we present a detailed model of a postsynaptic glutamatergic synapse that incorporates ionotropic and mGluR type I receptors, and we use this model to determine the role of the different receptors to the dynamics of postsynaptic calcium with different patterns of presynaptic activation. Our modeling framework includes glutamate vesicular release and diffusion in the cleft and a glutamate transporter that modulates extracellular glutamate concentration. Our results indicate that the contribution of mGluRs to changes in postsynaptic calcium concentration is minimal under basal stimulation conditions and becomes apparent only at high frequency of stimulation. Furthermore, the location of mGluRs in the postsynaptic membrane is also a critical factor, as activation of distant receptors contributes significantly less to calcium dynamics than more centrally located ones. These results confirm the important role of glutamate transporters and of the localization of mGluRs in postsynaptic sites in their signaling properties, and further strengthen the notion that mGluR activation significantly contributes to postsynaptic calcium dynamics only following high-frequency stimulation. They also provide a new tool to analyze the interactions between metabotropic and ionotropic glutamate receptors

Innovation et développement dans les systèmes agricoles et alimentaires

L’innovation est souvent présentée comme l’un des principaux leviers pour promouvoir un développement plus durable et plus inclusif. Dans les domaines de l’agriculture et de l’alimentation, l’innovation est marquée par des spécificités liées à sa relation à la nature, mais aussi à la grande diversité d’acteurs concernés, depuis les agriculteurs jusqu’aux consommateurs, en passant par les services de recherche et de développement. L’innovation émerge des interactions entre ces acteurs, qui mobilisent des ressources et produisent des connaissances dans des dispositifs collaboratifs, afin de générer des changements. Elle recouvre des domaines aussi variés que les pratiques de production, l’organisation des marchés, ou les pratiques alimentaires. L’innovation est reliée aux grands enjeux de développement : innovation agro-écologique, innovation sociale, innovation territoriale, etc. Cet ouvrage porte un regard sur l’innovation dans les systèmes agricoles et alimentaires. Il met un accent particulier sur l’accompagnement de l’innovation, en interrogeant les méthodes et les organisations, et sur l’évaluation de l’innovation au regard de différents critères. Il s’appuie sur des réflexions portées par différentes disciplines scientifiques, sur des travaux de terrain conduits tant en France que dans de nombreux pays du Sud, et enfin sur les expériences acquises en accompagnant des acteurs qui innovent. Il combine des synthèses sur l’innovation et des études de cas emblématiques pour illustrer les propos. L’ouvrage est destiné aux enseignants, professionnels, étudiants et chercheurs

Atlas des artères perforantes de la peau du tronc et des membres

LYON1-BU Santé (693882101) / SudocSudocFranceF

Exploiter les résultats d'analyses chimique des sols archéologiques à l'aide des statistiques spatiales

International audienc

Analyse multi-élémentaire : vers l’interprétation des témoins invisibles des activités humaines passées

International audienceAncient human activities leave behind chemical pollution in the soil on which they took place. By identifying this pollution on archaeological sites, it is possible to trace back the activities. A number of analytical techniques can be used to measure chemical elements in the soil. X-ray fluorescence spectrometry (XRF) is a chemical analysis technique that offers archaeologists many advantages over more conventional techniques. In addition to its application for the non-destructive study of various artefacts, it can also be used to study the soil at archaeological sites. The development of XRF in recent years has made this technique particularly popular with archaeologists. It does not require long and complex preparation phases, offers numerous results in a single analysis and is inexpensive. However, this analysis technique does require certain precautions to be taken during sampling. Sampling is a crucial process in the chemical study of soil in archaeology. Its parameters need to be considered in advance of the operations, especially as it is possible to carry out prospecting even before the excavation begins. However, poor sampling can lead to bias, which in turn can lead to errors in the results and subsequent interpretations. The aim of this presentation is to discuss the importance of sampling parameters in the chemical study of soils in archaeology, as well as the most commonly used protocols. Concrete examples of archaeological studies will be used to illustrate the advantages and disadvantages of the various settings.Les activités humaines anciennes laissent des pollutions chimiques dans les sols sur lesquels ils se sont déroulés. En identifiant ces pollutions sur les sites archéologiques, il est possible de remonter aux activités. Le dosage des éléments chimiques dans les sols peut s’effectuer par de nombreuses techniques d’analyses. La spectrométrie de fluorescence des rayons X (XRF) est une technique d’analyse chimique qui présente de nombreux avantages pour l’archéologue par rapport aux techniques plus classiques. Outre son application pour l’étude non destructive des différents mobiliers, elle peut également être employée pour étudier le sol des sites archéologiques. Le développement de la XRF ces dernières années amène cette technique à être particulièrement employée par les archéologues. En effet, elle ne nécessite pas de longues et complexes phases de préparation, offre de nombreux résultats en une seule analyse et est bon marché. Cependant, cette technique d’analyse nécessite de prendre certaines précautions lors de l’échantillonnage. Il s’agit d’un processus crucial dans l’étude chimique des sols en archéologie. Ses paramètres doivent être pensés en amont des opérations, d’autant qu’il est possible d’effectuer des prospections avant même l’ouverture de la fouille. Cependant, un échantillonnage mal effectué peut entraîner des biais qui vont à leur tour entraîner des erreurs dans les résultats puis dans les interprétations qui en découlent. Cette communication vise à discuter de l’importance du paramétrage de l’échantillonnage dans l’étude chimique des sols en archéologie, ainsi que des protocoles les plus couramment utilisés. Les exemples concrets d’études archéologiques seront utilisés pour illustrer les avantages et les inconvénients des différents paramétrages

Climate benefit of a future hydrogen economy

Hydrogen is recognised as an important future energy vector for applications in many sectors. Hydrogen is an indirect climate gas which induces perturbations of methane, ozone, and stratospheric water vapour, three potent greenhouse gases. Using data from a state-of-the-art global numerical model, here we calculate the hydrogen climate metrics as a function of the considered time-horizon and derive a 100-yr Global Warming Potential of 12.8 ± 5.2 and a 20-yr Global Warming Potential of 40.1 ± 24.1. The considered scenarios for a future hydrogen transition show that a green hydrogen economy is beneficial in terms of mitigated carbon dioxide emissions for all policy-relevant time-horizons and leakage rates. In contrast, the carbon dioxide and methane emissions associated with blue hydrogen reduce the benefit of a hydrogen economy and lead to a climate penalty at high leakage rate or blue hydrogen share. The leakage rate and the hydrogen production pathways are key leverages to reach a clear climate benefit from a large-scale transition to a hydrogen economy

Climate benefit of a future hydrogen economy

International audienceHydrogen is recognised as an important future energy vector for applications in many sectors. Hydrogen is an indirect climate gas which induces perturbations of methane, ozone, and stratospheric water vapour, three potent greenhouse gases. Using data from a state-of-the-art global numerical model, here we calculate the hydrogen climate metrics as a function of the considered time-horizon and derive a 100-year Global Warming Potential of 12.8 ± 5.2 and a 20-year Global Warming Potential of 40.1 ± 24.1. The considered scenarios for a future hydrogen transition show that a green hydrogen economy is beneficial in terms of mitigated carbon dioxide emissions for all policy-relevant time-horizons and leakage rates. In contrast, the carbon dioxide and methane emissions associated with blue hydrogen reduce the benefit of a hydrogen economy and lead to a climate penalty at high leakage rate or blue hydrogen share. The leakage rate and the hydrogen production pathways are key leverages to reach a clear climate benefit from a large-scale transition to a hydrogen economy

Comparison of geophysical prospecting and geochemical prospecting at the medieval and modern Cistercian Abbey of Carnoët (Finistère, France)

International audienc