Unique biofilm signature, drug susceptibility and decreased virulence in Drosophila through the Pseudomonas aeruginosa two-component system PprAB.

Bacterial biofilm is considered as a particular lifestyle helping cells to survive hostile environments triggered by a variety of signals sensed and integrated through adequate regulatory pathways. Pseudomonas aeruginosa, a Gram-negative bacterium causing severe infections in humans, forms biofilms and is a fantastic example for fine-tuning of the transition between planktonic and community lifestyles through two-component systems (TCS). Here we decipher the regulon of the P.

Tracking the time course of word-frequency effects in auditory word recognition with event-related potentials.

Although the word-frequency effect is one of the most established findings in spoken-word recognition, the precise processing locus of this effect is still a topic of debate. In this study, we used event-related potentials (ERPs) to track the time course of the word-frequency effect. In addition, the neighborhood density effect, which is known to reflect mechanisms involved in word identification, was also examined.

Influence of the length of imogolite-like nanotubes on their cytotoxicity and genotoxicity toward human dermal cells.

Physical-chemical parameters such as purity, structure, chemistry, length, and aspect ratio of nanoparticles (NPs) are linked to their toxicity. Here, synthetic imogolite-like nanotubes with a set chemical composition but various sizes and shapes were used as models to investigate the influence of these physical parameters on the cyto- and genotoxicity and cellular uptake of NPs. The NPs were characterized using X-ray diffraction (XRD), small angle X-ray scattering (SAXS), and atomic force microscopy (AFM).

Computed tomography, histological and ultrasonic measurements of adolescent scoliotic rib hump geometrical and material properties.

In Adolescent Idiopathic Scoliosis (AIS), numerical models can enhance orthopaedic or surgical treatments and provide reliable insights into the mechanism of progression. Computational methods require knowledge of relevant parameters, such as the specific geometrical or material properties of the AIS rib, about which there is currently a lack of information. The aim of our study was to determine the geometrical and material properties (Young's modulus [E] and Poisson's ratio [ν]) for AIS rib bones.

Motion-based prediction is sufficient to solve the aperture problem.

In low-level sensory systems, it is still unclear how the noisy information collected locally by neurons may give rise to a coherent global percept. This is well demonstrated for the detection of motion in the aperture problem: as luminance of an elongated line is symmetrical along its axis, tangential velocity is ambiguous when measured locally. Here, we develop the hypothesis that motion-based predictive coding is sufficient to infer global motion.

Effects of humanness and gender in voice processing.

When we observe a producible human movement, the brain performs a specific perception-action matching process, which possibly facilitates perceptual processing. In this work, we wanted to study whether the producibility of a sound affects the speed at which it is categorized. Participants were presented with isolated sounds, either sung by a natural male or female voice ('producible') or distorted by saturation ('non-producible'), and had to categorize them as produced by a voice or by a machine.

Cellular and molecular processes leading to embryo formation in sponges: evidences for high conservation of processes throughout animal evolution.

The emergence of multicellularity is regarded as one of the major evolutionary events of life. This transition unicellularity/pluricellularity was acquired independently several times (King 2004). The acquisition of multicellularity implies the emergence of cellular cohesion and means of communication, as well as molecular mechanisms enabling the control of morphogenesis and body plan patterning.

Solving the puzzles of cutin and suberin polymer biosynthesis.

Cutin and suberin are insoluble lipid polymers that provide critical barrier functions to the cell wall of certain plant tissues, including the epidermis, endodermis and periderm. Genes that are specific to the biosynthesis of cutins and/or aliphatic suberins have been identified, mainly in Arabidopsis thaliana. They notably encode acyltransferases, oxidases and transporters, which may have either well-defined or more debatable biochemical functions.

To what extent do we hear phonemic contrasts in a non-native regional variety? Tracking the dynamics of perceptual processing with EEG.

This combined ERP and behavioral experiment explores the dynamics of processing during the discrimination of vowels in a non-native regional variety. Southern listeners were presented with three word forms, two of which are encountered in both Standard and Southern French ([kot] and [kut]), whereas the third one exists in Standard but not Southern French ([kot]). EEG recordings suggest that all of the word pairs were discriminated by the listeners, although discrimination arose about 100ms later for the pairs which included the non-native word form than for those which contained word forms common to both French varieties.

Protein analysis meets visual word recognition: a case for string kernels in the brain.

It has been recently argued that some machine learning techniques known as Kernel methods could be relevant for capturing cognitive and neural mechanisms (Jäkel, Schölkopf, & Wichmann, 2009). We point out that ''String kernels,'' initially designed for protein function prediction and spam detection, are virtually identical to one contending proposal for how the brain encodes orthographic information during reading. We suggest some reasons for this connection and we derive new ideas for visual word recognition that are successfully put to the test.

Monitoring photonic nanojets from microsphere arrays by femtosecond laser ablation of thin films.

By comparing finite-difference time-domain near field simulations and femtosecond laser ablation of thin films, we characterize in three dimensional-space photonic nanojets from microsphere arrays. We demonstrate periodic drilling of transparent films with thickness up to 100 nm (onto absorbing substrates) is feasible with 1-microm diameter silica spheres. Working with larger polystyrene spheres, the apparent increase of the propagation length of the photonic nanojets makes possible to drill films as thick as 500 nm.

Context-related frequency modulations of macaque motor cortical LFP beta oscillations.

The local field potential (LFP) is a population measure, mainly reflecting local synaptic activity. Beta oscillations (12-40 Hz) occur in motor cortical LFPs, but their functional relevance remains controversial. Power modulation studies have related beta oscillations to a "resting" motor cortex, postural maintenance, attention, sensorimotor binding and planning.

Molecular origins and consequences of High-800 LH2 in Roseobacter denitrificans.

Roseobacter denitrificans is a marine bacterium capable of using a wide variety of different metabolic schemes and in particular is an anoxygenic aerobic photosynthetic bacterium. In the work reported here we use a deletion mutant that we have constructed to investigate the structural origin of the unusual High-800 light-harvesting complex absorption in this bacterium. We suggest that the structure is essentially unaltered when compared to the usual nonameric complexes but that a change in the environment of the C(13:1) carbonyl group is responsible for the change in spectrum.

Virtual reality and exercise: behavioral and psychological effects of visual feedback.

We herein report an experimental study examining the potential positive effects of Virtual Reality (VR) feedback during an indoor bicycling exercise. Using a regular bike coupled to a VR system, we compared conditions of no VR feedback, VR feedback and VR feedback with the presence of a virtual coach, acting as a pacer. In VR feedback conditions, we observed a decreased level of perceived exertion and an increased level of enjoyment of physical activity, when compared to a regular exercise situation (no VR feedback).

Mineralogy and leachability of gasified sewage sludge solid residues.

Gasification of sewage sludge produces combustible gases as well as tar and a solid residue as by-products. This must be taken into account when determining the optimal thermal conditions for the gasification process. In this study, the influence of temperature, heating atmosphere and residence time on the characteristics of the gasified sewage sludge residues is investigated.

Toward a new role for plasma membrane sodium-dependent glutamate transporters of astrocytes: maintenance of antioxidant defenses beyond extracellular glutamate clearance.

The primary function assigned to the sodium-dependent glutamate transporters, also known as excitatory amino acid transporters (EAATs), is to maintain the extracellular glutamate concentration in the low micromolar range, allowing glutamate to be used as a signaling molecule in the brain and preventing its cytotoxic effects. However, glutamate and cyst(e)ine, that is also a substrate of EAATs, are also important metabolites used for instance in the synthesis of the main antioxidant glutathione. This review describes the evidence suggesting that EAATs, by providing glutathione precursors, are crucial to prevent oxidative death in particular cells of the nervous system while being dispensable in others.

Stability of nanoparticles in water.

Aqueous systems represent a likely carrier for manufactured nanoparticles upon their introduction into the natural environment. Their behavior in water, and in turn the risk that is posed by these materials to environmental and human communities, is a top concern. In terms of risk assessment, nanoparticle exposure to organisms is largely driven by their dispersion and behavior in aqueous systems, while their potential hazard, although not always well understood, is often related to their surface speciation.

Single-spanning transmembrane domains in cell growth and cell-cell interactions: More than meets the eye?

As a whole, integral membrane proteins represent about one third of sequenced genomes, and more than 50% of currently available drugs target membrane proteins, often cell surface receptors. Some membrane protein classes, with a defined number of transmembrane (TM) helices, are receiving much attention because of their great functional and pharmacological importance, such as G protein-coupled receptors possessing 7 TM segments. Although they represent roughly half of all membrane proteins, bitopic proteins (with only 1 TM helix) have so far been less well characterized.

Concurrent aggregation and deposition of TiO2 nanoparticles in a sandy porous media.

The possibility of simultaneous particle aggregation and deposition in a porous medium was examined for the case of TiO(2) nanoparticles (NPs). While potential for particle aggregation is typically assumed to be negligible in porous media due to favored interactions with porous media surfaces (collectors), we show that nanoscale particle dimensions may favor aggregation kinetics, thus altering the transport and retention of these materials in saturated porous media. When surface chemistry favors nanoparticle-nanoparticle attachment (alpha(pp)) over nanoparticle-collector attachment (alpha(pc)), the rate of particle aggregation within pores may be comparable to that of deposition at ratios of collector to nanoparticle surface areas as high as 40.

Effects of lexical status and morphological complexity in masked priming: An ERP study.

Two masked priming experiments examined behavioural and event-related potential responses to simplex target words (e.g., flex) preceded by briefly presented, masked, derived word primes (flexible-flex), complex nonword primes formed by an illegal combination of the target word and a real suffix (flexify-flex), and simplex nonword primes formed by adding a nonsuffix word ending to the target (flexint-flex).

Modelling honeybee visual guidance in a 3-D environment.

In view of the behavioral findings published on bees during the last two decades, it was proposed to decipher the principles underlying bees' autopilot system, focusing in particular on these insects' use of the optic flow (OF). Based on computer-simulated experiments, we developed a vision-based autopilot that enables a "simulated bee" to travel along a tunnel, controlling both its speed and its clearance from the right wall, left wall, ground, and roof. The flying agent thus equipped enjoys three translational degrees of freedom on the surge (x), sway (y), and heave (z) axes, which are uncoupled.

Phonological neighbourhood effects in French spoken-word recognition.

According to activation-based models of spoken-word recognition, words with many and high-frequency phonological neighbours are processed more slowly than words with few and low-frequency phonological neighbours. Although considerable empirical support for inhibitory neighbourhood density effects has accumulated, especially in English, little or nothing is known about the effects of neighbourhood frequency and its interaction with neighbourhood density. In this study we examine both effects first separately and then simultaneously in French lexical decision experiments.

Dynamic interaction between "Go" and "Stop" signals in the saccadic eye movement system: New evidence against the functional independence of the underlying neural mechanisms.

We investigated human oculomotor behaviour in a Go-NoGo saccadic task in which the saccadic response to a peripheral visual target was to be inhibited in a minority of trials (NoGo trials). Different from classical experimental paradigms on the inhibitory control of intended actions, in our task the inhibitory cue was identical to the saccadic target (used in Go trials) in timing, location and shape-the only difference being its colour. By analysing the latency and the metrics of saccades erroneously executed after a NoGo instruction (NoGo-escapes), we observed a characteristic pattern of performance: first, we observed a decrease in the amplitude of NoGo-escapes with increasing latency; second, we revealed a consistent population of long-latency small saccades opposite in direction to the NoGo cue; finally, we found a strong side-specific inhibitory effect in terms of saccadic reaction times, on trials immediately following a NoGo trial.

Spatiotemporal dynamics of visual attention during saccade preparation: Independence and coupling between attention and movement planning.

During the preparation of a saccadic eye movement, a visual stimulus is more efficiently processed when it is spatially coincident with the saccadic target as compared to when the visual and the saccadic targets are displayed at different locations. We studied the coupling between visual selective attention and saccadic preparation by measuring orientation acuity of human subjects at different locations relative to the saccadic target and at different delays relative to the saccade cue onset. First, we generalized previous results (E.