Molecules making waves in axon guidance

The exquisite complexity of neural connectivity depends upon the precise navigation of axons to their targets in the developing nervous system. How is this achieved? Signals from the environment are assumed to impinge on growth cone receptors and thus steer axons in the right direction, but the molecular details of this process have been largely unknown. Recently, impressive progress has been made in identifying families of molecules that may underlie this process. Candidate diffusible guidance molecules include the netrins and semaphorins, whereas membrane-associated Eph receptors and their ligands are proposed to influence guidance by cellcell contact. Characterization of receptors for some of these molecules now promises the dissection of the signalling pathways that dictate axonal responses to pathfinding cues

Aide au diagnostic des pathologies neurologiques par traitement d'images couleur de fibres de myéline

L’analyse par diffraction des rayons X sur des échantillons de biopsie du nerf sural fournit une aide au diagnostic des neuropathologies. Ce procédé coûteux en personnels et en moyens matériels ne donne cependant que des mesures globales des composantes de la fibre nerveuse. Afin d’obtenir des mesures plus précises de la distribution des surfaces et des constituants des fibres, nous proposons une méthode automatisée par analyse d’images numériques couleur en microscopie optique. Notre méthode repose sur une classification couleur non supervisée qui nous permet de segmenter les images des fascicules nerveux en différentes régions correspondant aux structures histologiques à mesurer. Nos résultats montrent la faisabilité de la méthode proposée et fournissent une mesure rapide et précise pour l’aide au diagnostic des neuropathologies

Study on the Impact of the NS in the Performance of Meta-Heuristics in the TSP

Meta-heuristics have been applied for a long time to the Travelling Salesman Problem (TSP) but information is still lacking in the determination of the parameters with the best performance. This paper examines the impact of the Simulated Annealing (SA) and Discrete Artificial Bee Colony (DABC) parameters in the TSP. One special consideration of this paper is how the Neighborhood Structure (NS) interact with the other parameters and impacts the performance of the meta-heuristics. NS performance has been the topic of much research, with NS proposed for the best-known problems, which seem to imply that the NS influences the performance of meta-heuristics, more that other parameters. Moreover, a comparative analysis of distinct meta-heuristics is carried out to demonstrate a non-proportional increase in the performance of the NS.This work is supported by FEDER Funds through the "Programa Operacional Factores de Competitividade - COMPETE" program and by National Funds through FCT "FundaqAo para a Ciencia e a Tecnologia" under the project: FCOMP-01-0124-FEDER-PEst-OE/EEl/U10760/2011, PEst-OE/EEI/UI0760/2014, and PEst2015-2020.info:eu-repo/semantics/publishedVersio

Regional Anesthesia for Bilateral Carpal Tunnel Release

Carpal Tunnel Syndrome is the most common nerve entrapment neuropathy with over 60% of diagnosed patients presenting with bilateral median nerve involvement. Bilateral upper extremity surgery presents unique anesthesia challenges, yet surgeons are increasingly interested in performing simultaneous bilateral carpal tunnel release (BCTR) procedures. Regional anesthesia techniques traditionally employed for unilateral hand procedures are impractical, and general anesthesia is expensive and incurs added risk. A cost effective and efficient anesthesia plan for BCTR is therefore needed. Objective: Conduct a literature search to support the administration of an efficient and safe anesthesia technique for BCTR utilizing local infiltration and median nerve block. Methods: Electronic searches were conducted for current pertinent information published in anesthesia, hand surgery and plastic surgery journals within the past 5 years. Information gathered was assimilated to make an evidence based recommendation for a BCTR anesthesia technique. Results: BCTR is a more cost effective and time efficient treatment for bilateral carpal tunnel syndrome than a staged unilateral approach. Local anesthesia with median nerve block with or without sedation is a cost efficient and safe anesthesia strategy for BCTR

Sexual selection modulates genetic conflicts and patterns of genomic imprinting

This work was supported by Portuguese National Funds, through FCT - Fundação para a Ciência e a Tecnologia, within the project UID/BIA/00329/2013, as well as through GFS PhD Scholarship (SFRH/BD/109726/2015) and through SAMV Post-Doctoral Research Grant (SFRH/BPD/66042/2009), and by a Natural Environment Research Council Independent Research Fellowship (AG, Grant Number NE/K009524/1).Recent years have seen a surge of interest in linking the theories of kin selection and sexual selection. In particular, there is a growing appreciation that kin selection, arising through demographic factors such as sex-biased dispersal, may modulate sexual conflicts,including in the context of male-female arms races characterized by coevolutionary cycles.However, evolutionary conflicts of interest need not only occur between individuals, but may also occur within individuals, and sex-specific demography is known to foment such intragenomic conflict in relation to social behavior. Whether and how this logic holds in the context of sexual conflict – and, in particular, in relation to coevolutionary cycles – remains obscure. We develop a kin-selection model to investigate the interests of different genes involved in sexual and intragenomic conflict, and we show that consideration of these conflicting interests yields novel predictions concerning parent-of-origin-specific patterns of gene expression and the detrimental effects of different classes of mutation and epimutation at loci underpinning sexually-selected phenotypes.Publisher PDFPeer reviewe

Superconductivity and charge carrier localization in ultrathin La1.85Sr0.15CuO4/La2CuO4\mathbf{{La_{1.85}Sr_{0.15}CuO_4}/{La_2CuO_4}} bilayers

$\mathrm{La_{1.85}Sr_{0.15}CuO_4}$/$\mathrm{La_2CuO_4}$ (LSCO15/LCO) bilayers with a precisely controlled thickness of N unit cells (UCs) of the former and M UCs of the latter ([LSCO15\_N/LCO\_M]) were grown on (001)-oriented {\slao} (SLAO) substrates with pulsed laser deposition (PLD). X-ray diffraction and reciprocal space map (RSM) studies confirmed the epitaxial growth of the bilayers and showed that a [LSCO15\_2/LCO\_2] bilayer is fully strained, whereas a [LSCO15\_2/LCO\_7] bilayer is already partially relaxed. The \textit{in situ} monitoring of the growth with reflection high energy electron diffraction (RHEED) revealed that the gas environment during deposition has a surprisingly strong effect on the growth mode and thus on the amount of disorder in the first UC of LSCO15 (or the first two monolayers of LSCO15 containing one $\mathrm{CuO_2}$ plane each). For samples grown in pure $\mathrm{N_2O}$ gas (growth type-B), the first LSCO15 UC next to the SLAO substrate is strongly disordered. This disorder is strongly reduced if the growth is performed in a mixture of $\mathrm{N_2O}$ and $\mathrm{O_2}$ gas (growth type-A). Electric transport measurements confirmed that the first UC of LSCO15 next to the SLAO substrate is highly resistive and shows no sign of superconductivity for growth type-B, whereas it is superconducting for growth type-A. Furthermore, we found, rather surprisingly, that the conductivity of the LSCO15 UC next to the LCO capping layer strongly depends on the thickness of the latter. A LCO capping layer with 7~UCs leads to a strong localization of the charge carriers in the adjacent LSCO15 UC and suppresses superconductivity. The magneto-transport data suggest a similarity with the case of weakly hole doped LSCO single crystals that are in a so-called {"{cluster-spin-glass state}"

Spectroscopic imaging of single atoms within a bulk solid

The ability to localize, identify and measure the electronic environment of individual atoms will provide fundamental insights into many issues in materials science, physics and nanotechnology. We demonstrate, using an aberration-corrected scanning transmission microscope, the spectroscopic imaging of single La atoms inside CaTiO3. Dynamical simulations confirm that the spectroscopic information is spatially confined around the scattering atom. Furthermore we show how the depth of the atom within the crystal may be estimated.Comment: 4 pages and 3 figures. Accepted in Phys.Rev.Let