Local surface modification via confined electrochemical deposition with FluidFM †

International audienceWe show how the association of AFM with microfluidics, namely FluidFM, is a valuable approach for the versatile electrochemical creation of patterns having diverse shapes and topologies. Localization of the electrochemical reactions was obtained by confining the electroactive species in the microchannel and dispensing them at a precise position through the aperture of FluidFM probes. The force feedback enabled a gentle approach onto the electrode as well as a gentle contact during both the lithography procedure as well as in situ topographical AFM imaging just before or after deposition. As model systems, we demonstrate electroplating of copper and electrografting of organic moieties by reduction of aryldiazonium salts

Signatures of valence fluctuations in CeCu2Si2 under high pressure

Simultaneous resistivity and a.c.-specific heat measurements have been performed under pressure on single crystalline CeCu2Si2 to over 6 GPa in a hydrostatic helium pressure medium. A series of anomalies were observed around the pressure coinciding with a maximum in the superconducting critical temperature, $T_c^{max}$. These anomalies can be linked with an abrupt change of the Ce valence, and suggest a second quantum critical point at a pressure $P_v \simeq 4.5$ GPa, where critical valence fluctuations provide the superconducting pairing mechanism, as opposed to spin fluctuations at ambient pressure. Such a valence instability, and associated superconductivity, is predicted by an extended Anderson lattice model with Coulomb repulsion between the conduction and f-electrons. We explain the T-linear resistivity found at $P_v$ in this picture, while other anomalies found around $P_v$ can be qualitatively understood using the same model.Comment: Submitted to Phys. Rev.

Exploiting Anisotropy of Plasmonic Nanostructures with Polarization-Modulation Infrared Linear Dichroism Microscopy (μPM-IRLD).

Metallic nanostructures that exhibit plasmon resonances in the mid-infrared range are of particular interest for a variety of optical processes where the infrared excitation and/or emission could be enhanced. This plasmon-mediated enhancement can potentially be used towards highly sensitive detection of an analyte(s) by techniques such as surface-enhanced infrared absorption (SEIRA). To maximize the SEIRA enhancement, it is necessary to prepare highly tuned plasmonic resonances over a defined spectral range that can span over several microns. Noteworthy, nanostructures with anisotropic shapes exhibit multiple resonances that can be exploited by controlling the polarization of the input light. This study demonstrates the role of polarization-modulation infrared linear dichroism coupled to microscopy measurements (μPM-IRLD) as a powerful means to explore the optical properties of anisotropic nanostructures. Quantitative μPM-IRLD measurements were conducted on a 2 series of dendritic fractals as model structures to explore the role of structural anisotropy on the resulting surface-enhanced infrared absorption and sensing application. Once functionalized with an analyte, the μPM-IRLD SEIRA results highlight that it is possible to selectively enhance further vibrational modes of analytes making use of the structural anisotropy of the metallic nanostructure

New User-Friendly Approach to Obtain an Eisenberg Plot and Its Use as a Practical Tool in Protein Sequence Analysis

The Eisenberg plot or hydrophobic moment plot methodology is one of the most frequently used methods of bioinformatics. Bioinformatics is more and more recognized as a helpful tool in Life Sciences in general, and recent developments in approaches recognizing lipid binding regions in proteins are promising in this respect. In this study a bioinformatics approach specialized in identifying lipid binding helical regions in proteins was used to obtain an Eisenberg plot. The validity of the Heliquest generated hydrophobic moment plot was checked and exemplified. This study indicates that the Eisenberg plot methodology can be transferred to another hydrophobicity scale and renders a user-friendly approach which can be utilized in routine checks in protein–lipid interaction and in protein and peptide lipid binding characterization studies. A combined approach seems to be advantageous and results in a powerful tool in the search of helical lipid-binding regions in proteins and peptides. The strength and limitations of the Eisenberg plot approach itself are discussed as well. The presented approach not only leads to a better understanding of the nature of the protein–lipid interactions but also provides a user-friendly tool for the search of lipid-binding regions in proteins and peptides

Measures for interoperability of phenotypic data: minimum information requirements and formatting

BackgroundPlant phenotypic data shrouds a wealth of information which, when accurately analysed and linked to other data types, brings to light the knowledge about the mechanisms of life. As phenotyping is a field of research comprising manifold, diverse and time-consuming experiments, the findings can be fostered by reusing and combining existing datasets. Their correct interpretation, and thus replicability, comparability and interoperability, is possible provided that the collected observations are equipped with an adequate set of metadata. So far there have been no common standards governing phenotypic data description, which hampered data exchange and reuse.ResultsIn this paper we propose the guidelines for proper handling of the information about plant phenotyping experiments, in terms of both the recommended content of the description and its formatting. We provide a document called “Minimum Information About a Plant Phenotyping Experiment”, which specifies what information about each experiment should be given, and a Phenotyping Configuration for the ISA-Tab format, which allows to practically organise this information within a dataset. We provide examples of ISA-Tab-formatted phenotypic data, and a general description of a few systems where the recommendations have been implemented.ConclusionsAcceptance of the rules described in this paper by the plant phenotyping community will help to achieve findable, accessible, interoperable and reusable data

Transcriptional Regulation of Inflammasomes

Inflammasomes are multimolecular complexes with potent inflammatory activity. As such, their activity is tightly regulated at the transcriptional and post-transcriptional levels. In this review, we present the transcriptional regulation of inflammasome genes from sensors (e.g., NLRP3) to substrates (e.g., IL-1β). Lineage-determining transcription factors shape inflammasome responses in different cell types with profound consequences on the responsiveness to inflammasome-activating stimuli. Pro-inflammatory signals (sterile or microbial) have a key transcriptional impact on inflammasome genes, which is largely mediated by NF-κB and that translates into higher antimicrobial immune responses. Furthermore, diverse intrinsic (e.g., circadian clock, metabolites) or extrinsic (e.g., xenobiotics) signals are integrated by signal-dependent transcription factors and chromatin structure changes to modulate transcriptionally inflammasome responses. Finally, anti-inflammatory signals (e.g., IL-10) counterbalance inflammasome genes induction to limit deleterious inflammation. Transcriptional regulations thus appear as the first line of inflammasome regulation to raise the defense level in front of stress and infections but also to limit excessive or chronic inflammation

Understanding of discharge-charge processes inside porous binder- free carbon nanotube membrane as cathode materials in non-aqueous Li-Air batteries

International audienceNew efficient energy storage devices are one of the most important challenges for researchers all over the world. Because of the growth of portable technologies on the market (automobile, mobile phones …), it is essential to develop new devices to efficiently store increasing quantities of energy. The most promising technologies, which could replace Li-ion batteries used currently in this kind of devices, operate by ion intercalation (Na-ion or all-solid-state batteries) or by electrochemical reactions (Lithium-sulfur or Metal-air batteries). The latter work by reducing small molecules, like dioxygen, to metal oxide species in Lithium-air devices, and whose main discharge product is Li2O2. Lithium-air battery is one important alternative because of its largest theoretical energy storage density. Nevertheless, the cyclability remains the main difficulty to overcome, either on the anode by the dendrimer formation of lithium particles, or in the cathode by the non-reversibility of oxygen reduction reaction (oxidation of ORR products), which occur during charge process and obstruct the oxygen and lithium cation flux. In this work, we are interested in the understanding of discharge-charge electrochemical/chemical processes inside porous cathode materials in non-aqueous Li-Air batteries. We use binder-free carbon nanotube (CNT) membranes as microporous cathode material and dimethylsulfoxyde (DMSO)/LiClO4 as electrolyte. The cathode section was analyzed by coupling electrochemical analysis using an air half-cell and post-mortem analysis using SEM to observe the product morphologies of the top, the bottom and through the thickness of CNT membranes (influence of the structure). XPS was also used to determine reaction products. Coupling these different techniques, it is possible to correlate the discharge conditions with the product morphologies and their locations inside the CNT membrane, in order to determine the key parameters that are responsible for the membrane blockage during cycling

Environnement et inégalités sociales

La protection de l’environnement s’est, dès ses origines, fondée sur les sciences naturelles et les techniques et, depuis plus récemment, elle interagit avec l’économie, mais ses relations avec des aspects sociaux ont été l’objet de moins d’attention. L’environnement appelle pourtant la préservation de la (qualité de la) vie, et l’homme est bien un animal social. Or, si l’objectif de protection de l’environnement est généralement formulé de façon consensuelle, il va évidemment se trouver décliné de façons différentes selon des différenciations sociales. La pleine prise en compte de ces interactions conduit à formuler une série de questions. Comment se répartissent les impacts environnementaux dans une société ?Comment les objectifs et les actions orientés vers la protection de l’environnement peuvent-ils être lus dans le prisme des catégories sociales ?Quels en sont plus particulièrement les bénéficiaires et les perdants ?Quels sont ceux qui peuvent faire entendre leur voix, et influencent les critères ?Quelles pistes envisager pour une limitation des impacts négatifs de la croissance économique dans un double objectif d’équité sociale et de réduction des nuisances environnementales ?Ces questions interrogent des aspects fondamentaux du développement durable et de l’écologie politique. Elles sont étudiées dans ce livre, en théorie et sur de nombreux cas pratiquesinfo:eu-repo/semantics/publishe