University of Lorraine

About: University of Lorraine is a education organization based out in Nancy, France. It is known for research contribution in the topics: Population & Nonlinear system. The organization has 11942 authors who have published 25010 publications receiving 425227 citations. The organization is also known as: Lorraine University.

Catching the Invisible: Mesial Temporal Source Contribution to Simultaneous EEG and SEEG Recordings

Abstract: Mesial temporal sources are presumed to escape detection in scalp electroencephalographic recordings. This is attributed to the deep localization and infolded geometry of mesial temporal structures that leads to a cancellation of electrical potentials, and to the blurring effect of the superimposed neocortical background activity. In this study, we analyzed simultaneous scalp and intracerebral electroencephalographic recordings to delineate the contribution of mesial temporal sources to scalp electroencephalogram. Interictal intracerebral spike networks were classified in three distinct categories: solely mesial, mesial as well as neocortical, and solely neocortical. The highest and earliest intracerebral spikes generated by the leader source of each network were marked and the corresponding simultaneous intracerebral and scalp electroencephalograms were averaged and then characterized both in terms of amplitude and spatial distribution. In seven drug-resistant epileptic patients, 21 interictal intracerebral networks were identified: nine mesial, five mesial plus neocortical and seven neocortical. Averaged scalp spikes arising respectively from mesial, mesial plus neocortical and neocortical networks had a 7.1 (n = 1,949), 36.1 (n = 628) and 10 (n = 1,471) µV average amplitude. Their scalp electroencephalogram electrical field presented a negativity in the ipsilateral anterior and basal temporal electrodes in all networks and a significant positivity in the fronto-centro-parietal electrodes solely in the mesial plus neocortical and neocortical networks. Topographic consistency test proved the consistency of these different scalp electroencephalogram maps and hierarchical clustering clearly differentiated them. In our study, we have thus shown for the first time that mesial temporal sources (1) cannot be spontaneously visible (mean signal-to-noise ratio −2.1 dB) on the scalp at the single trial level and (2) contribute to scalp electroencephalogram despite their curved geometry and deep localization.

X-ray elemental mapping techniques for elucidating the ecophysiology of hyperaccumulator plants

Abstract: Contents 'Summary' I. 'Introduction' II. 'Preparation of plant samples for X-ray micro-analysis' III. 'X-ray elemental mapping techniques' IV. 'X-ray data analysis' V. 'Case studies' VI. 'Conclusions' 'Acknowledgements' 'Author contributions' References Summary Hyperaccumulators are attractive models for studying metal(loid) homeostasis, and probing the spatial distribution and coordination chemistry of metal(loid)s in their tissues is important for advancing our understanding of their ecophysiology. X-ray elemental mapping techniques are unique in providing in situ information, and with appropriate sample preparation offer results true to biological conditions of the living plant. The common platform of these techniques is a reliance on characteristic X-rays of elements present in a sample, excited either by electrons (scanning/transmission electron microscopy), protons (proton-induced X-ray emission) or X-rays (X-ray fluorescence microscopy). Elucidating the cellular and tissue-level distribution of metal(loid)s is inherently challenging and accurate X-ray analysis places strict demands on sample collection, preparation and analytical conditions, to avoid elemental redistribution, chemical modification or ultrastructural alterations. We compare the merits and limitations of the individual techniques, and focus on the optimal field of applications for inferring ecophysiological processes in hyperaccumulator plants. X-ray elemental mapping techniques can play a key role in answering questions at every level of metal(loid) homeostasis in plants, from the rhizosphere interface, to uptake pathways in the roots and shoots. Further improvements in technological capabilities offer exciting perspectives for the study of hyperaccumulator plants into the future.

Continuum model for chiral induced spin selectivity in helical molecules

Abstract: A minimal model is exactly solved for electron spin transport on a helix. Electron transport is assumed to be supported by well oriented pz type orbitals on base molecules forming a staircase of definite chirality. In a tight binding interpretation, the spin-orbit coupling (SOC) opens up an effective πz − πz coupling via interbase px,y − pz hopping, introducing spin coupled transport. The resulting continuum model spectrum shows two Kramers doublet transport channels with a gap proportional to the SOC. Each doubly degenerate channel satisfies time reversal symmetry; nevertheless, a bias chooses a transport direction and thus selects for spin orientation. The model predicts (i) which spin orientation is selected depending on chirality and bias, (ii) changes in spin preference as a function of input Fermi level and (iii) back-scattering suppression protected by the SO gap. We compute the spin current with a definite helicity and find it to be proportional to the torsion of the chiral structure and the non-a...

Nanostructured electrodes for electrocatalytic advanced oxidation processes: From materials preparation to mechanisms understanding and wastewater treatment applications

Abstract: The implementation of nanostructured materials in electrochemistry implied the enhancement of conversion yield in fuel cell, in electrosynthesis of oxidants and electrolytic treatment for environmental protection, while it allowed reducing the detection limit in electroanalysis. Nanostructured materials are becoming a hot topic of research, especially in electrochemical treatment for environmental applications that is strongly related to the rise of graphene and subsequent 2D materials that emerged in the last ten years. Nano-structuration allows bringing new properties of the materials such as number of active sites and conductivity improvement. It can therefore enhance the heterogeneous catalysis mechanism at electrode surface. This is primordial since it makes increase the rate of electrochemical reactions that can be the rate limiting steps in electrocatalytic treatment. Such advanced materials contribute to make advanced electrochemical processes as “greener” processes than the conventional ones. This paper aims to be a comprehensive, critical, and accessible review of general interest. The literature covers mainly the last ten years’ period due to the recent topic, especially the last five years with the considerable increase of number of publications in this period. The contents particularly devote efforts to establish links between the nanostructured-based electrode properties and electrochemical treatment efficiency through the mechanisms involved. The perspectives about mechanisms understanding and electrodes stability improvement are especially discussed.