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Duplex ultrasound (DUS) is an essential tool for characterizing and monitoring arteriovenous (AV) access for hemodialysis. The aim of the work described here, requested by the French Society of Vascular Medicine in collaboration with the French-Speaking Vascular Access Society, is to propose a standardized methodology for performing and documenting DUS, taking into account the variety of AV access techniques and the problems routinely encountered. A steering committee reviewed the literature and selected the relevant references. A draft was prepared, and all items with missing or conflicting data were submitted to a Delphi consensus. The final document was discussed and approved by all participants. The principles of DUS evaluation of AV access consist of examination of the afferent artery, the anastomosis and the entire venous drainage system. DUS uses B-mode ultrasound, color flow, pulsed wave and power Doppler analysis. DUS can be used in a variety of clinical situations, which can directly influence the methodology of the examination and the interpretation of the results. Blood flow should be assessed as it correlates with the risk of thrombosis. The measurement should be adapted to the different anatomical and hemodynamic conditions encountered. Characterization of stenosis should take into account the residual diameter of the drainage vein and its hemodynamic consequences. Other complications can be assessed with a standardized DUS examination. When performed according to a rigorous methodology, DUS of the AV access allows a comprehensive assessment of its functionality and eliminates the need for further invasive diagnostic procedures. [ABSTRACT FROM AUTHOR]

Bacterial virulence is highly dynamic and context-dependent. For this reason, it is challenging to predict how molecular changes affect the growth of a pathogen in a host and its spread in host population. Two schools of thought have taken quite different directions to decipher the underlying principles of bacterial virulence. While molecular infection biology is focusing on the basic mechanisms of the pathogen-host interaction, evolution biology takes virulence as one of several parameters affecting pathogen spread in a host population. We review both approaches and discuss how they can complement each other in order to obtain a comprehensive understanding of bacterial virulence, its emergence, maintenance and evolution. [ABSTRACT FROM AUTHOR]

Transcranial Magnetic Stimulation (TMS) established itself as a powerful technique for probing and treating the human brain. Major technological evolutions, such as neuronavigation and robotized systems, have continuously increased the spatial reliability and reproducibility of TMS, by minimizing the influence of human and experimental factors. However, there is still a lack of efficient set-up procedure, which prevents the automation of TMS protocols. For example, the set-up procedure for defining the stimulation intensity specific to each subject is classically done manually by experienced practitioners, by assessing the motor cortical excitability level over the motor hotspot (HS) of a targeted muscle. This is time-consuming and introduces experimental variability. Therefore, we developed a probabilistic Bayesian model (AutoHS) that automatically identifies the HS position. Using virtual and real experiments, we compared the efficacy of the manual and automated procedures. AutoHS appeared to be more reproducible, faster, and at least as reliable as classical manual procedures. By combining AutoHS with robotized TMS and automated motor threshold estimation methods, our approach constitutes the first fully automated set-up procedure for TMS protocols. The use of this procedure decreases inter-experimenter variability while facilitating the handling of TMS protocols used for research and clinical routine. [ABSTRACT FROM AUTHOR]

Bacteriophage transfer (lysogenic conversion) promotes bacterial virulence evolution. There is limited understanding of the factors that determine lysogenic conversion dynamics within infected hosts. A murine Salmonella Typhimurium (S.Tm) diarrhea model was used to study the transfer of SopEΦ, a prophage from S.Tm SL1344, to S.Tm ATCC14028S. Gut inflammation and enteric disease triggered >55% lysogenic conversion of ATCC14028S within 3 days. Without inflammation, SopEΦ transfer was reduced by up to 105-fold. This was because inflammation (e.g., reactive oxygen species, reactive nitrogen species, hypochlorite) triggers the bacterial SOS response, boosts expression of the phage antirepressor Tum, and thereby promotes free phage production and subsequent transfer. Mucosal vaccination prevented a dense intestinal S.Tm population from inducing inflammation and consequently abolished SopEΦ transfer. Vaccination may be a general strategy for blocking pathogen evolution that requires disease-driven transfer of temperate bacteriophages. [ABSTRACT FROM AUTHOR]

During reading acquisition, beginning readers transition from serial to more parallel processing. The acquisition of word specific knowledge through orthographic learning is critical for this transition. However, the processes by which orthographic representations are acquired and fine-tuned as learning progresses are not well understood. Our aim was to explore the role of visual attention in this transition through computational modeling. We used the BRAID-Learn model, a Bayesian model of visual word recognition, to simulate the orthographic learning of 700 4-to 10-letter English known words and novel words, presented 5 times each to the model. The visual attention quantity available for letter identification was manipulated in the simulations to assess its influence on the learning process. We measured the overall processing time and number of attentional fixations simulated by the model across exposures and their impact on two markers of serial processing, the lexicality and length effects, depending on visual attention quantity. Results showed that the two lexicality and length effects were modulated by visual attention quantity. The quantity of visual attention available for processing further modulated novel word orthographic learning and the evolution of the length effect on processing time and number of attentional fixations across repeated exposures to novel words. The simulated patterns are consistent with behavioral data and the developmental trajectories reported during reading acquisition. Overall, the model predicts that the efficacy of orthographic learning depends on visual attention quantity and that visual attention may be critical to explain the transition from serial to more parallel processing. [ABSTRACT FROM AUTHOR]

Reasoning by analogy allows us to link distinct domains of knowledge and to transfer solutions from one domain to another. Analogical reasoning has been studied using various tasks that have generally required the consideration of the relationships between objects and their integration to infer an analogy schema. However, these tasks varied in terms of the level and the nature of the relationships to consider (e.g., semantic, visuospatial). The aim of this study was to identify the cerebral network involved in analogical reasoning and its specialization based on the domains of information and task specificity. We conducted a coordinate-based meta-analysis of 27 experiments that used analogical reasoning tasks. The left rostrolateral prefrontal cortex was one of the regions most consistently activated across the studies. A comparison between semantic and visuospatial analogy tasks showed both domain-oriented regions in the inferior and middle frontal gyri and a domain-general region, the left rostrolateral prefrontal cortex, which was specialized for analogy tasks. A comparison of visuospatial analogy to matrix problem tasks revealed that these two relational reasoning tasks engage, at least in part, distinct right and left cerebral networks, particularly separate areas within the left rostrolateral prefrontal cortex. These findings highlight several cognitive and cerebral differences between relational reasoning tasks that can allow us to make predictions about the respective roles of distinct brain regions or networks. These results also provide new, testable anatomical hypotheses about reasoning disorders that are induced by brain damage. Hum Brain Mapp 37:1953-1969, 2016. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

The remarkable capacity of the speech motor system to adapt to various speech conditions is due to an excess of degrees of freedom, which enables producing similar acoustical properties with different sets of control strategies. To explain how the central nervous system selects one of the possible strategies, a common approach, in line with optimal motor control theories, is to model speech motor planning as the solution of an optimality problem based on cost functions. Despite the success of this approach, one of its drawbacks is the intrinsic contradiction between the concept of optimality and the observed experimental intra-speaker token-to-token variability. The present paper proposes an alternative approach by formulating feedforward optimal control in a probabilistic Bayesian modeling framework. This is illustrated by controlling a biomechanical model of the vocal tract for speech production and by comparing it with an existing optimal control model (GEPPETO). The essential elements of this optimal control model are presented first. From them the Bayesian model is constructed in a progressive way. Performance of the Bayesian model is evaluated based on computer simulations and compared to the optimal control model. This approach is shown to be appropriate for solving the speech planning problem while accounting for variability in a principled way. [ABSTRACT FROM AUTHOR]

While the origin of language remains a somewhat mysterious process, understanding how human language takes specific forms appears to be accessible by the experimental method. Languages, despite their wide variety, display obvious regularities. In this paper, we attempt to derive some properties of phonological systems (the sound systems for human languages) from speech communication principles. We introduce a model of the cognitive architecture of a communicating agent, called COSMO (for “Communicating about Objects using Sensory–Motor Operations') that allows a probabilistic expression of the main theoretical trends found in the speech production and perception literature. This enables a computational comparison of these theoretical trends, which helps us to identify the conditions that favor the emergence of linguistic codes. We present realistic simulations of phonological system emergence showing that COSMO is able to predict the main regularities in vowel, stop consonant and syllable systems in human languages. [ABSTRACT FROM AUTHOR]

Introduction: The use of intravenous thrombolysis with alteplase for ischemic stroke in Europe is restricted to subjects aged <80 years. Recent studies have reported the efficacy and safety of alteplase in older patients. However, data concerning the quality of life (QOL) of these elderly subjects are sparse. Objectives: The aim of this study was to compare the QOL of patients aged ≥80 years with that of patients aged <80 years at 3 months after thrombolysis. Method: This was a prospective study comprising French-speaking patients aged >18 years treated using thrombolytic therapy for ischemic stroke at the Hospital of Tours (Tours, France) between June 2012 and January 2013. QOL was assessed using the Stroke Impact Scale (SIS). The presence of mood disorders or cognitive impairments was also assessed. Results: QOL was evaluated for 62 subjects among the 83 enrolled patients who received thrombolytic treatment; 21 patients were aged >80 years. Concerning scores on the SIS, using a multivariate analysis, only the memory and thinking score was significantly and negatively associated with the elderly population [odds ratio (OR) 0.036, 95 % confidence interval (CI) 0.004-0.339; p = 0.004]. No significant difference was observed among all the other QOL scores. Neurological recovery and functional status did not differ between the two groups. Conclusion: QOL after intravenous thrombolysis in the elderly population was comparable to that of younger subjects. Despite its small sample size, this study showed promising results in favor of intravenous thrombolysis in the elderly population and highlighted the importance of systematic screening for post-stroke cognitive impairment, particularly in this population. [ABSTRACT FROM AUTHOR]

The first aim of this work is to get highly accurate values of the diffusion–convection impedance for dissolved species reacting at the surface of a uniformly accessible rotating disk electrode (RDE). Three computation strategies are examined and compared for this purpose. Each procedure requires, first, a solution (series solution or numerical solution) of von Kármán approximation of the Navier–Stokes equations for evaluation of the components of fluid velocity induced by electrode rotation, and, next, a numerical solution of the one-dimensional diffusion–convection equation for RDE under harmonic conditions. The fully numerical method presented in this article provides benchmark data, which can be used to check the validity of previous derivations of the diffusion–convection impedance in the literature, as well as the accuracy of computation methods based on series expansions. Additional information upon the diffusion–convection impedance pertaining to RDE is reported in the supplementary material associated with this article. [ABSTRACT FROM AUTHOR]

Analysis of experimental EIS data in terms of equivalent circuits is the common approach used in most commercial software dedicated to EIS method. However, one-to-one assignment of impedance elements to particular electrochemical/physical processes causes difficulty, at the exception of the impedance calculated for one-step reactions. The example of EE reaction is dealt with in this article for the purpose of illustrating non-intuitive and sometimes unexpected features of equivalent circuits derived for a two-step electrochemical reaction involving only soluble diffusing species and electrons. [ABSTRACT FROM AUTHOR]

Topological, chemical and immunological barriers are thought to limit infection by enteropathogenic bacteria. However, in many cases these barriers and their consequences for the infection process remain incompletely understood. Here, we employed a mouse model for Salmonella colitis and a mixed inoculum approach to identify barriers limiting the gut luminal pathogen population. Mice were infected via the oral route with wild type S. Typhimurium (S. Tm) and/or mixtures of phenotypically identical but differentially tagged S. Tm strains (“WITS”, wild-type isogenic tagged strains), which can be individually tracked by quantitative real-time PCR. WITS dilution experiments identified a substantial loss in tag/genetic diversity within the gut luminal S. Tm population by days 2–4 post infection. The diversity-loss was not attributable to overgrowth by S. Tm mutants, but required inflammation, Gr-1+ cells (mainly neutrophilic granulocytes) and most likely NADPH-oxidase-mediated defense, but not iNOS. Mathematical modelling indicated that inflammation inflicts a bottleneck transiently restricting the gut luminal S. Tm population to approximately 6000 cells and plating experiments verified a transient, inflammation- and Gr-1+ cell-dependent dip in the gut luminal S. Tm population at day 2 post infection. We conclude that granulocytes, an important clinical hallmark of S. Tm-induced inflammation, impose a drastic bottleneck upon the pathogen population. This extends the current view of inflammation-fuelled gut-luminal Salmonella growth by establishing the host response in the intestinal lumen as a double-edged sword, fostering and diminishing colonization in a dynamic equilibrium. Our work identifies a potent immune defense against gut infection and reveals a potential Achilles' heel of the infection process which might be targeted for therapy. [ABSTRACT FROM AUTHOR]

Summary Antibiotics are powerful therapeutics but are not equally effective against all cells in bacterial populations. Bacteria that express an antibiotic-tolerant phenotype (“persisters”) can evade treatment [ 1 ]. Persisters can cause relapses of the infection after the end of the therapy [ 2 ]. It is still poorly understood whether persistence affects the evolution of bacterial virulence. During infections, persisters have been found preferentially at particular sites within the host [ 3, 4 ]. If bacterial virulence factors are required to reach such sites, treatment with antibiotics could impose selection on the expression of virulence genes, in addition to their well-established effects on bacterial resistance. Here, we report that treatment with antibiotics selects for virulence and fosters transmissibility of Salmonella Typhimurium. In a mouse model for Salmonella diarrhea, treatment with the broad-spectrum antibiotic ciprofloxacin reverses the outcome of competition between wild-type bacteria and avirulent mutants that can spontaneously arise during within-host evolution [ 5 ]. While avirulent mutants take over the gut lumen and abolish disease transmission in untreated mice, ciprofloxacin tilts the balance in favor of virulent, wild-type bacteria. This is explained by the need for virulence factors to invade gut tissues and form a persistent reservoir. Avirulent mutants remain in the gut lumen and are eradicated. Upon cessation of antibiotic treatment, tissue-lodged wild-type pathogens reseed the gut lumen and thereby facilitate disease transmissibility to new hosts. Our results suggest a general principle by which antibiotic treatment can promote cooperative virulence during within-host evolution, increase duration of transmissibility, and thereby enhance the spread of an infectious disease. [ABSTRACT FROM AUTHOR]

A new species of proteocephalid cestodes, provisionally assigned to the polyphyletic genus Ophiotaenia La Rue, 1911 (Cestoda: Proteocephalidae), is described from Compsophis infralineatus (Günther) (Serpentes: Pseudoxyrhophiidae) endemic to Madagascar. Ophiotaenia oreae n. sp. differs from all African and Asian species of Ophiotaenia by possessing more uterine diverticula (68–82 on one side). It is also characterised by the absence of an apical organ, the relative sizes of the cirrus-sac and ovary, the almost equatorial position of the gonopore, the diameter of the embryophore, and other biometric characteristics. Phylogenetic relationships of the new species indicate its relatedness to Indomalayan and Australasian proteocephalids from reptiles. Ophiotaenia oreae n. sp. formed a well-supported clade composed of species of Australophiotaenia de Chambrier, Beveridge and Scholz, 2018 from Australian snakes, Macrobothriotaenia ficta (Meggitt, 1931) from Xenopeltis unicolor Reinwardt in Boie from Vietnam, Ophiotaenia sp. from Trimeresurus flavomaculatus (Gray) from the Philippines, and Ophiotaenia bungari de Chambrier, Binh and Scholz, 2012 from Bungarus fasciatus (Schneider) from Vietnam. The only proteocephalid from Madagascan snakes sequenced so far, Ophiotaenia lapata Rambeloson, Ranaivoson and de Chambrier, 2012 from Madagascarophis colubrinus (Schlegel), does not form a monophyletic group with the new species. The actual species diversity of reptilian cestodes in Madagascar is undoubtedly underestimated. Because of the assumed strict (oioxenous) host specificity of reptilian proteocephalids and rich fauna of snakes occurring in Madagascar, it is plausible to expect the existence of dozens new species of proteocephalids on this island. [Display omitted] • A new species of tapeworm from an endemic snake of Madagascar is described. • Phylogenetic relationships of the new species indicate its relatedness to Indomalayan and Australasian tapeworms. • The only species from Malagasy snakes sequenced so far, O. lapata , does not form a monophyletic group with O. oreae n. sp. • The actual species diversity of reptilian cestodes in Madagascar is undoubtedly underestimated. [ABSTRACT FROM AUTHOR]

Highlights: [•] Analytical formulation of the concentration profile derived from Levich theory. [•] Explicit series formulation for generalization to finite values of the Schmidt number. [•] Comparison of numerical, analytical and series solutions of diffusion–convection equation. [•] Explicit series formulation of the limiting current for a uniformly accessible RDE. [Copyright &y& Elsevier]

We propose a mathematical model of the Path Integration (PI) process. Its core assumption is that orientations of a path are summarized by circular probability distributions. We compare our model with classical, deterministic models of PI and find that, although they are indistinguishable in terms of information encoded, the probabilistic model is more parsimonious when considering navigation strategies. We show how sensory events can enrich the probability distributions memorized, resulting in a continuum of navigation strategies, from PI to stimulus-triggered response. We analyze the combination of circular probability distributions (e.g., multicue fusion), and demonstrate that, contrary to the linear case, adding orientation cues does not always increase reliability of estimates. We discuss experimental predictions entailed by our model. [ABSTRACT FROM PUBLISHER]

Pathogens often infect hosts through collective actions: they secrete growth-promoting compounds or virulence factors, or evoke host reactions that fuel the colonization of the host. Such behaviours are vulnerable to the rise of mutants that benefit from the collective action without contributing to it; how these behaviours can be evolutionarily stable is not well understood. We address this question using the intestinal pathogen Salmonella enterica serovar Typhimurium (hereafter termed S. typhimurium), which manipulates its host to induce inflammation, and thereby outcompetes the commensal microbiota. Notably, the virulence factors needed for host manipulation are expressed in a bistable fashion, leading to a slow-growing subpopulation that expresses virulence genes, and a fast-growing subpopulation that is phenotypically avirulent. Here we show that the expression of the genetically identical but phenotypically avirulent subpopulation is essential for the evolutionary stability of virulence in this pathogen. Using a combination of mathematical modelling, experimental evolution and competition experiments we found that within-host evolution leads to the emergence of mutants that are genetically avirulent and fast-growing. These mutants are defectors that exploit inflammation without contributing to it. In infection experiments initiated with wild-type S. typhimurium, defectors increase only slowly in frequency. In a genetically modified S. typhimurium strain in which the phenotypically avirulent subpopulation is reduced in size, defectors rise more rapidly, inflammation ceases prematurely, and S. typhimurium is quickly cleared from the gut. Our results establish that host manipulation by S. typhimurium is a cooperative trait that is vulnerable to the rise of avirulent defectors; the expression of a phenotypically avirulent subpopulation that grows as fast as defectors slows down this process, and thereby promotes the evolutionary stability of virulence. This points to a key role of bistable virulence gene expression in stabilizing cooperative virulence and may lead the way to new approaches for controlling pathogens. [ABSTRACT FROM AUTHOR]

Summary: The mammalian intestine is colonized by a dense microbial community, the microbiota. Homeostatic and symbiotic interactions facilitate the peaceful co-existence between the microbiota and the host, and inhibit colonization by most incoming pathogens ('colonization resistance'). However, if pathogenic intruders overcome colonization resistance, a fierce, innate inflammatory defense can be mounted within hours, the adaptive arm of the immune system is initiated, and the pathogen is fought back. The molecular nature of the homeostatic interactions, the pathogen's ability to overcome colonization resistance, and the triggering of native and adaptive mucosal immune responses are still poorly understood. To study these mechanisms, the streptomycin mouse model for Salmonella diarrhea is of great value. Here, we review how S. Typhimurium triggers mucosal immune responses by active (virulence factor elicited) and passive (MyD88-dependent) mechanisms and introduce the S. Typhimurium mutants available for focusing on either response. Interestingly, mucosal defense turns out to be a double-edged sword, limiting pathogen burdens in the gut tissue but enhancing pathogen growth in the gut lumen. This model allows not only studying the molecular pathogenesis of Salmonella diarrhea but also is ideally suited for analyzing innate defenses, microbe handling by mucosal phagocytes, adaptive secretory immunoglobulin A responses, probing microbiota function, and homeostatic microbiota-host interactions. Finally, we discuss the general need for defined assay conditions when using animal models for enteric infections and the central importance of littermate controls. [ABSTRACT FROM AUTHOR]

In this paper, we study the collaboration of perception and action representations involved in cursive letter recognition and production. We propose a mathematical formulation for the whole perception-action loop, based on probabilistic modeling and Bayesian inference, which we call the Bayesian Action-Perception (BAP) model. Being a model of both perception and action processes, the purpose of this model is to study the interaction of these processes. More precisely, the model includes a feedback loop from motor production, which implements an internal simulation of movement. Motor knowledge can therefore be involved during perception tasks. In this paper, we formally define the BAP model and show how it solves the following six varied cognitive tasks using Bayesian inference: i) letter recognition (purely sensory), ii) writer recognition, iii) letter production (with different effectors), iv) copying of trajectories, v) copying of letters, and vi) letter recognition (with internal simulation of movements). We present computer simulations of each of these cognitive tasks, and discuss experimental predictions and theoretical developments. [ABSTRACT FROM AUTHOR]

This paper concerns the incremental learning of hierarchies of representations of space in artificial or natural cognitive systems. We propose a mathematical formalism for defining space representations (Bayesian Maps) and modelling their interaction in hierarchies of representations (sensorimotor interaction operator). We illustrate our formalism with a robotic experiment. Starting from a model based on the proximity to obstacles, we learn a new one related to the direction of the light source. It provides new behaviours, like phototaxis and photophobia. We then combine these two maps so as to identify parts of the environment where the way the two modalities interact is recognisable. This classification is a basis for learning a higher level of abstraction map that describes the large-scale structure of the environment. In the final model, the perception-action cycle is modelled by a hierarchy of sensorimotor models of increasing time and space scales, which provide navigation strategies of increasing complexities. [ABSTRACT FROM AUTHOR]

The virulence of many human pathogens does not seem to be an evolutionarily selected trait, but an accidental by-product of the selection that operates in another ecological context. We investigated the possibility that virulence of the extraintestinal pathogenic Escherichia coli (ExPEC) strains, which frequently cause disease in the host in which they asymptomatically colonize the intestine, is the consequence of commensalism. Most of the ExPEC virulence factors are clustered on genomic islands called pathogenicity-associated islands (PAIs). We constructed and characterized several mutants of the ExPEC 536 strain with either (i) deletions of each single PAI or (ii) a complete deletion of all seven PAIs. In vitro phenotypic characterization of 536 mutants showed that the seven PAIs were dispensable for growth in the absence of external stress, as well as under a range of biologically relevant stressors, i.e., serum, bile, and oxidative, nitrosative, hyperosmotic, and acidic stress. However, challenge against the wild-type (WT) strain in a murine model shows that the deletion of all seven PAIs drastically reduces the fitness of 536 during persistent intestinal colonization. This defect seems to be linked to the hypermotility observed for mutants devoid of all seven PAIs. In addition, we show that PAls diminish fitness of their carrier during growth in urine, suggesting that urinary tract infections are unlikely to provide selective pressure for the maintenance of ExPEC PAIs. Our results are in accordance with the coincidental-evolution hypothesis postulating that extraintestinal E. coli virulence is a by-product of commensalism. [ABSTRACT FROM AUTHOR]

Abstract: The Fletcher''s proposition [S. Fletcher, Electrochemistry Communications 3 (2001) 692–696] to represent a three-terminal electrochemical cell by its two-terminal electrical equivalent for the purpose of the analysis of its electrical responses helps significantly to elucidate peculiarities of the electrochemical impedance (EI) such as inductive or capacitive artifacts. The Fletcher''s two-terminal equivalent cell of 3rd order appears however to be redundant as including more circuit elements then necessary to represent the 2nd order impedance of the electrochemical cell. As the alternative to this we recommend two equivalent circuits of 2nd order, both simpler then the original Fletcher''s circuit and both better candidates to play the role of the canonical electrical model. Transformation from three-terminal to two-terminal circuit done here with Mathematica® program appeared relatively simple and it was also possible to relax Fletcher''s restraint of representing the working electrode by single resistance. Instead, we used two-terminal electrical models with the working electrode represented by series resistance, double layer capacitance and charge transfer resistance. EI spectra of such extended configuration also present capacitive and inductive artifacts referred to by Fletcher in his model. These artifacts do depend on the impedance of the working electrode. [Copyright &y& Elsevier]

Abstract: The diffusely adhering Escherichia coli (Afa/Dr DAEC) are associated with recurrent urinary tract infections in adults as well as with diarrheal disease in infants. We previously demonstrated that in wild-type strain IH11128, the Dr fimbriae is released in the extracellular medium in response to multiple environmental signals such as temperature, low aeration and rich medium. A number of molecules of eukaryotic origin, such as catecholamines, have been reported to stimulate bacterial growth and virulence factor production. We show that norepinephrine affects the production and release of Dr fimbriae in Afa/Dr DAEC WT-IH11128 bacteria. The regulatory mechanism involved with norepinephrine-induced Dr fimbriae liberation was apparently due to a differential induction of genes draC, encoding the usher, and draE, encoding the major fimbrial subunit. In addition, we show that the released Dr fimbriae induces the phosphorylation of the mitogen-activated protein kinase, extracellular signal-regulated kinase 1/2 (ERK1/2) and the production of the pro-inflammatory cytokine, IL-8 in fully differentiated cultured human intestinal Caco-2/TC7 cells. [Copyright &y& Elsevier]

Abstract: In the first part of this work, we showed that numerical inversion of Laplace transform (NILT) methods could be readily applied to compute the responses of electrochemical systems to small input signals from any reasonable model of the system immittance that is the impedance for current-controlled techniques and the admittance for potential-controlled techniques. The aim of this second article is to provide some applications examples in different fields of electrochemical kinetics. The response of a polymer exchange membrane fuel cell to a small current pulse is computed. The responses of corrosion systems to small potential step/ramp signals are also dealt with. The response of electrochemical systems to a sinusoidal perturbation of electrode potential is investigated. Finally, both Faradaic and non-Faradaic components of the total current are computed by NILT methods under potential- and current-controlled conditions. [Copyright &y& Elsevier]

Abstract: Dynamic modelling of electrochemical systems in the time-domain generally requires the inversion of Laplace transforms. Unfortunately, many practical systems exist for which the inverse transforms cannot be derived analytically. A new approach of the dynamics of electrochemical systems, investigated under small-signal conditions, is proposed in this work. The method is based on numerical inversion of Laplace transforms and, more especially, on the Gaver–Stehfest (GS) inversion formula. General and explicit formulations of the time-domain responses of stable systems to a small potential step/ramp and to a small current step/pulse are derived in part I of this work from linear combinations of values of the system immittance that is the admittance for potential-controlled techniques and the impedance for current-controlled techniques. The GS approach of system dynamics is illustrated by taking the example of finite-space diffusion of electroactive species. Application to corrosion systems, polymer exchange membrane fuel cells and thin-film ion-insertion electrodes will be presented in the next parts of this work. [Copyright &y& Elsevier]

Abstract: Extraintestinal pathogenic Escherichia coli (ExPEC) strains cause disease by invading normally sterile niches within the host body, e.g., urinary tract, blood and cerebrospinal fluid. Infections due to ExPEC strains, in particular urinary tract infections, cause considerable morbidity and significant health-care costs. The goal of our study is to evaluate whether Caenorhabditis elegans can be used as a model to study phenotypic and genetic virulence determinants of ExPEC strains. For this purpose, we used a collection of 31 E. coli strains isolated during acute extra-intestinal infections or from the feces of healthy individuals. For all strains, the phylogeny, the presence of ExPEC virulence factors, the resistance to biologically relevant stressors (bile, human serum and lysozyme), the motility, the growth rate, the virulence in C. elegans and in a murine septicaemia model has been established. The results show that there is a strong link between virulence in C. elegans and certain phenotypic and genetic virulence predictors of ExPEC strains determinable in vitro. Furthermore, there is a significant correlation between virulence of different ExPEC strains in C. elegans and in the murine model. Therefore, our results suggest that C. elegans can be used as a model to study virulence determinants of ExPEC strains. [Copyright &y& Elsevier]

Abstract: Afa/Dr diffusely adhering Escherichia coli have been shown to cause urinary tract infections and enteric infections. Virulence of Dr-positive IH11128 bacteria is associated with the presence of Dr fimbriae. In this report, we show for the first time that the Dr fimbriae are released in the extracellular medium in response to multiple environmental signals. Production and secretion of Dr fimbriae are clearly thermoregulated. A comparison of the amounts of secreted fimbriae showed that the secretion is drastically increased during anaerobic growth in minimal medium. The effect of anaerobiosis on secretion seemed to depend on both the growth phase and the culture medium. The secretion was maximal during the logarithmic-phase growth and corresponded to 27 and 57% of total Dr fimbriae produced by bacteria grown in mineral medium+glucose and LB broth, respectively. Thus, the anaerobic environment of the colon would favour the secretion of Dr fimbriae during bacterial multiplication. The controlled release of the Dr fimbriae, which is carried out in the absence of cellular lysis, appears independent of the action of proteases or a process of maturation. The mechanism employed in the liberation of Dr fimbriae thus seems different from that described for the adhesins FHA and Hap of Bordetella pertussis and Haemophilus influenzae. [Copyright &y& Elsevier]

Abstract: Recently a new mechanism for copper deposition has been proposed by Gabrielli et al. [C. Gabrielli, P. Moçotéguy, H. Perrot, R. Wiart, J. Electroanal. Chem. 572 (2004) 367]. In this mechanism cupric ions are supposed to be reduced by two different paths. The first path is a direct discharge of cupric ions in two steps, and the second follows a parallel path through a catalytic complexation with chloride ions and adsorption of copper (I) chloride onto the copper surface. In the second path, chloride ions are consumed in the first step and produced in the second step, therefore chloride ions act as catalysts. The rates of the two steps of the second path are equal under steady-state condition and the concentration of Cl− anion is constant in the electrolytic solution. In contrast the step rates are not equal under dynamic conditions causing a concentration impedance of chloride ions with a rather unusual expression. Such an impedance is calculated and thoroughly examined in this paper. Finally, decomposition of the Faradaic impedance into the sum of concentration impedances of adsorbed species and chloride ions makes it possible to determine the contribution of each concentration impedance to the global impedance of the electrode. [Copyright &y& Elsevier]

Abstract: First, a theoretical expression of diffusion layer thickness is derived for simple (one-step) electrochemical reactions with reversible electron-transfer processes investigated by LSV under semi-infinite linear diffusion conditions in the electrolytic solution. The above expression is compared to previous results in electrochemical literature. In particular, it is shown that Padé-approximants used in previous works fail to predict the potential dependence of diffusion layer thickness over the whole potential domain. More generally, the change of diffusion layer thickness with respect to time is derived in this article in terms of reaction rate and mass-transport conditions, irrespective of the interfacial reaction mechanism and the electron-transfer kinetics. The formulation applies to one-dimensional diffusion processes eventually coupled with homogeneous chemical reactions, using electrochemical techniques such as potential and current step methods, linear sweep voltammetry (LSV), etc. Finally, experimental investigation of FeIII/FeII redox couple by LSV is presented as an illustration of the theoretical derivation in this work. [Copyright &y& Elsevier]

Abstract: In this theoretical EIS study of the redox reaction Fe3++e−↔Fe2+ occurring at multilayer electrodes, four points are dealt with in detail: firstly, a recursive formulation allowing the exact calculation of the impedance whatever the number of layers is given (‘Russian dolls’ behaviour of the mass-transport functions). Secondly, the study of the two bilayer electrodes Pt/layer 1/layer 2 and Pt/layer 2/layer 1 shows that the layer order drastically influences the electrochemical response of the system, and proves that a multilayer electrode cannot be simply treated as a monolayer electrode. Thirdly, it is shown that all the key parameters (thicknesses, diffusion coefficients, and partition coefficients) cannot be only determined by EIS, another combined physicochemical technique being indispensable. Fourthly, an exhaustive study of bilayer electrodes in quiescent solution is made and all the possible impedance diagram shapes are plotted. [Copyright &y& Elsevier]

Plastic heterogeneities of hexagonal close-packed (HCP) materials are numerically investigated at the grain level. Intensive use of parallel Finite Elements computations enables us to study micro-plasticity of realistic 3D multicrystalline aggregates, including, macroscopic mechanical responses but also average responses in each grain and particularly local stress and strain fields. This paper focuses on three applications of this simulation method. The first part of this paper is devoted to a fine analysis of micro-plasticity of HCP materials. Intergranular but also intragranular stress and strain heterogeneities are described and micro-plasticity patterns are displayed throughout the 3D microstructures. A special attention is paid to the sensitivity of simulations with respect to the mesh discretization, the element interpolation and the geometrical representation of grain boundaries, in terms of macroscopic and local responses. Later, a simplified homogenization method is evaluated, regarding results of the first part. Afterwards, this method is applied with a zirconium alloy to identify a set of coefficients for a single crystal plasticity model. Finally, in order to provide critical information for intergranular damage phenomena (reported in literature for zirconium alloys), the third part provides a statistical analysis of over-stresses at grain boundaries. [Copyright &y& Elsevier]

The Ni|H2SO4 system is a well-known oscillator under galvanostatic conditions. New experimental results obtained forcing the Ni|1 M H2SO4 electrochemical oscillator under galvanostatic conditions are presented. First a simple dissolution–passivation model explaining potential oscillations under galvanostatic conditions is used to predict the possible behaviour of experimental systems. The non-linear dynamic behaviour of the model is studied numerically near the Hopf bifurcation. The classical behaviour for forced self-oscillating systems, such as periodic or quasi-periodic behaviour, may occur when the current density is modulated by a sinusoidal signal. A phase portrait showing the main Arnold tongues where phase locking occurs is plotted. Next, several types of behaviour theoretically predicted for forced oscillators are observed experimentally for the Ni|1 M H2SO4 system, for example phase locking, bi-periodic behaviour, etc. Finally the consequences of bi-periodic bebaviour on impedance measurements are pointed out experimentally. [Copyright &y& Elsevier]

The redox reaction FeIII + e ↔ FeII is studied at a Nafion®-filmed Pt electrode using both steady-state and EIS methods. It is shown that the fitting of the EIS experimental data can be greatly improved by using the new concept of a ‘theoretical–experimental hybrid model’, i.e., by introducing experimental data obtained at a bare electrode in the theoretical model for a filmed electrode. It is also shown that a combined steady-state and EIS study cannot lead to a separate determination of the three key parameters of the system: the diffusion coefficient in the polymer film (Df), the thickness of the film (L), and the partition coefficient between the solution and the polymer (γ), only the two parameters γDf/L and L2/Df being obtained from experimental data by a curve fitting procedure. Finally, an exhaustive theoretical EIS study in quiescent solution is also proposed. [Copyright &y& Elsevier]

The theoretical expression for the mass-transport impedance is derived considering diffusion-trapping controlled processes studied under restricted linear diffusion conditions (impermeable surface) and assuming uniform distribution of trapping sites in the electrode. The relevant expression applies to hydrogen diffusion-trapping in metals and alloys, as well as ion insertion-trapping in host materials provided the metallic type potential distribution is assumed in electrolyte/host material systems. The impedance diagram shape is discussed based on two dimensionless parameters, i.e. the ratio of the diffusion resistance to the trapping resistance and the ratio of the diffusion time constant to the trapping time constant. A case diagram is plotted to determine the validity conditions for the limiting expressions of the mass-transport impedance derived for diffusion and trapping control. The conditions for characterization of diffusion with trapping from EIS data are discussed depending on the system parameters and the frequency range accessible experimentally. The influence of non-uniform spacial distribution of trapping sites is also discussed. Distribution of trapping sites with different kinetic constants and concentrations is finally envisaged. [Copyright &y& Elsevier]

A new method for measuring separately anode and cathode impedances (ZA and ZC) of an electrochemical generator running on constant load is proposed. In these conditions, the measurement of ZA and ZC is not as simple as under galvanostatic conditions. Measurements are carried out first on a dummy cell and next on a commercial direct methanol fuel cell (DMFC) under galvanostatic conditions and using the new proposed method. The comparison of the results validate our method, showing that it is a powerful method for fuel cell electrochemical impedance spectroscopy (EIS) characterization under natural running conditions. [Copyright &y& Elsevier]

Under transient power conditions in pressurized water reactor, zircaloy-4 fuel claddings are possibly submitted to stress corrosion cracking by volatile fission products. The localization of stress and strain in the inner surface of the cladding and the local aspects of the damage phenomena incite to consider a modeling at the granular scale. At this scale, the behavior of multicrystals is described by a crystal plasticity model including the local orientation of each grain and the Zy-4 slip-system families. Representative microstructures are meshed (2D and 3D) in order to evaluate intergranular but also intragranular heterogenities of the stress and strain fields. Large strain heterogenities appear due to deformation incompatibilities between grains, which induce over-stresses at the grain boundaries. 3D computations of multicrystalline aggregates are performed in order to compute the distribution of the normal stresses at the grain boundaries with respect to the angle between the load direction and the normal to the grain boundary. Effects of neighborhood is evaluated. In addition, an intergranular damage model is proposed. The formulation of this model is based on a decomposition of the strength at grain boundaries into normal and shear components. Finally, results on 2D aggregates are presented and show examples of anisotropic damage patterns. [Copyright &y& Elsevier]

A new dissolution–depassivation mechanism showing a non-trivial complex S-shaped polarization curve due to the Frumkin isotherm hypothesis has been studied. A potential domain exists for sufficiently low values of the Frumkin interaction parameter where a negative differential resistance is observed. For this mechanism, the electrode potential acts as an essential system variable due to the double layer capacitance. Harmonic and relaxation oscillations can be observed for the dissolution–depassivation mechanism under galvanostatic control (GC). Hopf bifurcation gives rise to oscillations under GC only for sufficiently high values of the double layer capacitance. Bifurcation diagrams are plotted. [Copyright &y& Elsevier]

How is orthographic knowledge acquired? In line with the self-teaching hypothesis, most computational models assume that phonological recoding has a pivotal role in orthographic learning. However, these models make simplifying assumptions on the mechanisms involved in visuo-orthographic processing. Against evidence from eye movement data during orthographic learning, they assume that orthographic information on novel words is immediately available and accurately encoded after a single exposure. In this paper, we describe BRAID-Learn, a new computational model of orthographic learning. BRAID-Learn is a probabilistic and hierarchical model that incorporates the mechanisms of visual acuity, lateral interference, and visual attention involved in word recognition. Orthographic learning in the model rests on three main mechanisms: first, visual attention moves over the input string to optimize the gain of information on letter identity at each fixation; second, top-down lexical influence is modulated as a function of stimulus familiarity; third, after exploration, perceived information is used to create a new orthographic representation or stabilize a better-specified representation of the input word. BRAID-Learn was challenged on its capacity to simulate the eye movement patterns reported in humans during incidental orthographic learning. In line with the behavioral data, the model predicts a larger decline with exposures in number of fixations and processing time for novel words than for known words. For novel words, most changes occur between the first and second exposure, that is to say, after creation in memory of a new orthographic representation. Beyond phonological recoding, our results suggest that visuo-attentional exploration is an intrinsic portion of orthographic learning seldom taken into consideration by models or theoretical accounts. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: Whether motor neuron diseases (MNDs) can be considered in some cases of paraneoplastic syndromes is controversial. We report a case of rapidly progressive motor neuronopathy following a diagnosis of breast carcinoma, with a presence of anti-Ri antibodies, and a novel SOD1 gene mutation. Observation: An 80-year-old woman with mucinous adenocarcinoma of the left breast for 4years developed sub-acute quadriparesis. Myography revealed chronic denervation signs. The patient had serum anti-Ri onconeural antibodies. The diagnosis of paraneoplastic MND was established. Because of a familial history of ALS, a genetic analysis for familial ALS was performed. We identified a novel heterozygous mutation in SOD1 gene, SOD I18del. This mutation may reflect a genetic predisposition to develop a MND, inducing fragility of motor neurons. Neurological improvement was observed after three months of both intravenous gamma globulin and corticosteroids. Conclusion: The present observation supports the idea that MND can be considered as a paraneoplastic syndrome. A combination of anti-Ri onconeural antibodies and a particular SOD1 gene mutation, consisting in risk factor, might be in cause in the process of motor neuron death. When in doubt, paraneoplastic cause should be suspected in the differential diagnosis of MND. Immunotherapy treatment may lead to a favorable outcome. [Copyright &y& Elsevier]

Longitudinal studies on mainstream children and training studies in the dyslexic population suggest that visual attention span (VAS) abilities contribute to reading acquisition. We evaluated to what extent VAS training in beginning readers might enhance later literacy skills. A large cohort of 453 children was followed from the beginning to the end of Grade 1. A first group of students was trained on a custom‐designed digital application—called EVASION—that targeted VAS abilities. Another group used the GraphoGame application, while the third was a “business‐as‐usual” group. A total training time of 10 h was recommended; training was performed during the regular school day, under the sole supervision of teachers. Pre–post intervention assessment revealed higher VAS, higher reading fluency improvement, and higher postintervention spelling skills in the EVASION group. Children who spent more time playing with EVASION improved more in both VAS and literacy skills. In the whole population, VAS enhancement predicted reading fluency improvement and posttraining spelling skills, independently of other reading related skills and of the class effect. The overall findings suggest that training VAS in the classroom might prevent difficulties in learning to read and spell. Evidence for longitudinal effects of VAS training on literacy skills support a causal relationship. In improving multiletter parallel processing, training would translate into better orthographic learning, yielding higher reading fluency and spelling skills. [ABSTRACT FROM AUTHOR]

We report the case of a 78-year-old patient admitted to the hospital for behavioral and psychological disorders consisting in impressions of presence of a stranger located behind the bathroom mirror, who strikingly shared the patient’s appearance but was considered a different person, yet. We discuss how this case can be interpreted as an atypical Capgras syndrome for his mirror image and how it suggests an adjustment of the classical dual-route model that sustains face recognition between covert (or affective) and overt neural pathways. [ABSTRACT FROM PUBLISHER]

Background: Because of insufficient data about their benefit–risk ratio in real life, drugs used for Alzheimer's disease (AD; cholinesterase inhibitors and memantine) were withdrawn from the list of reimbursable drugs in France on 1 August 2018. Objectives: In this context, this study aimed to investigate the effects of the removal of AD drugs from the list of reimbursed drugs among patients followed in memory centres in France, in terms of prevalence and factors associated with drug discontinuation and evolution of disease management and cognition after drug discontinuation. Methods: This is an observational study based on data from the National Alzheimer Data Bank ('Banque Nationale Alzheimer' [BNA]), which centralizes information about patients consulting in memory centres. The drug discontinuation rate was estimated among patients receiving AD drugs at the last visit before the end of reimbursement. Factors associated with drug discontinuation were investigated among sociodemographic and disease characteristics, as well as among the use of healthcare resources before the end of reimbursement. We compared the evolution of disease management (psychotropic drugs and non-pharmacological interventions) and Mini-Mental State Examination (MMSE) score during the year following the end of reimbursement among patients with a diagnosis of AD. Results: Among the 19,380 patients of the study sample (62.5% females, mean age 81 years, 86.8% with a diagnosis of AD), 19.5% discontinued their treatment after the end of reimbursement. The main factors associated with drug discontinuation were the type of dementia and lower MMSE level. Compared with patients with a diagnosis of AD, those with vascular dementia were more likely to stop their treatment, whereas those with dementia with Lewy bodies were less likely to discontinue. Among patients with a diagnosis of AD, drug discontinuation was associated with increased use of psychotropic medications, especially antidepressants, and non-pharmacological interventions afterwards, but there was no difference regarding the evolution of MMSE score. Conclusion: This study provides real-life information about the use of AD drugs after they were withdrawn from reimbursement in France and shows that drug discontinuation was limited among patients followed in memory centres and accompanied by increased use of other healthcare resources. [ABSTRACT FROM AUTHOR]

Auditory speech perception enables listeners to access phonological categories from speech sounds. During speech production and speech motor learning, speakers' experience matched auditory and somatosensory input. Accordingly, access to phonetic units might also be provided by somatosensory information. The present study assessed whether humans can identify vowels using somatosensory feedback, without auditory feedback. A tongue-positioning task was used in which participants were required to achieve different tongue postures within the /e, ", a/ articulatory range, in a procedure that was totally nonspeech like, involving distorted visual feedback of tongue shape. Tongue postures were measured using electromagnetic articulography. At the end of each tongue-positioning trial, subjects were required to whisper the corresponding vocal tract configuration with masked auditory feedback and to identify the vowel associated with the reached tongue posture. Masked auditory feedback ensured that vowel categorization was based on somatosensory feedback rather than auditory feedback. A separate group of subjects was required to auditorily classify the whispered sounds. In addition, we modeled the link between vowel categories and tongue postures in normal speech production with a Bayesian classifier based on the tongue postures recorded from the same speakers for several repetitions of the /e, ", a/ vowels during a separate speech production task. Overall, our results indicate that vowel categorization is possible with somatosensory feedback alone, with an accuracy that is similar to the accuracy of the auditory perception of whispered sounds, and in congruence with normal speech articulation, as accounted for by the Bayesian classifier. [ABSTRACT FROM AUTHOR]

Summary: Immunology research in the last 50 years has made huge progress in understanding the mechanisms of anti‐bacterial defense of deep, normally sterile, tissues such as blood, spleen and peripheral lymph nodes. In the intestine, with its dense commensal microbiota, it seems rare that this knowledge can be simply translated. Here we put forward the idea that perhaps it is not always the theory of immunology that is lacking to explain mucosal immunity, but rather that we have overlooked crucial parts of the mucosal immunological language required for its translation: namely intestinal and bacterial physiology. We will try to explain this in the context of intestinal secretory antibodies (mainly secretory IgA), which have been described to prevent, to alter, to not affect, or to promote colonization of the intestine and gut‐draining lymphoid tissues, and where effector mechanisms have remained elusive. In fact, these apparently contradictory outcomes can be generated by combining the basic premises of bacterial agglutination with an understanding of bacterial growth (i.e. secretory IgA‐driven enchained growth), fluid handling and bacterial competition in the gut lumen. [ABSTRACT FROM AUTHOR]

The word length effect in Lexical Decision (LD) has been studied in many behavioral experiments but no computational models has yet simulated this effect. We use a new Bayesian model of visual word recognition, the BRAID model, that simulates expert readers' performance. BRAID integrates an attentional component modeled by a Gaussian probability distribution, a mechanism of lateral interference between adjacent letters and an acuity gradient, but no phonological component. We explored the role of visual attention on the word length effect using 1,200 French words from 4 to 11 letters. A series of five simulations was carried out to assess (a) the impact of a single attentional focus versus multiple shifts of attention on the word length effect and (b) how this effect is modulated by variations in the distribution of attention. Results show that the model successfully simulates the word length effect reported for humans in the French Lexicon Project when allowing multiple shifts of attention for longer words. The magnitude and direction of the effect can be modulated depending on the use of a uniform or narrow distribution of attention. The present study provides evidence that visual attention is critical for the recognition of single words and that a narrowing of the attention distribution might account for the exaggerated length effect reported in some reading disorders. [ABSTRACT FROM AUTHOR]

Immunoglobulin A is a class of antibodies produced by the adaptive immune system and secreted into the gut lumen to fight pathogenic bacteria. We recently demonstrated that the main physical effect of these antibodies is to enchain daughter bacteria, i.e. to cross-link bacteria into clusters as they divide, preventing them from interacting with epithelial cells, thus protecting the host. These links between bacteria may break over time. We study several models using analytical and numerical calculations. We obtain the resulting distribution of chain sizes, that we compare with experimental data. We study the rate of increase in the number of free bacteria as a function of the replication rate of bacteria. Our models show robustly that at higher replication rates, bacteria replicate before the link between daughter bacteria breaks, leading to growing cluster sizes. On the contrary at low growth rates two daughter bacteria have a high probability to break apart. Thus the gut could produce IgA against all the bacteria it has encountered, but the most affected bacteria would be the fast replicating ones, that are more likely to destabilize the microbiota. Linking the effect of the immune effectors (here the clustering) with a property directly relevant to the potential bacterial pathogeneicity (here the replication rate) could avoid to make complex decisions about which bacteria to produce effectors against. [ABSTRACT FROM AUTHOR]