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International audience; Unilateral vestibular loss (UVL) induces a characteristic vestibular syndrome composed of various posturo-locomotor, oculomotor, vegetative and perceptivo-cognitive symptoms. Functional deficits are progressively recovered over time during vestibular compensation, that is supported by the expression of multiscale plasticity mechanisms. While the dynamic of post-UVL posturo-locomotor and oculomotor deficits is well characterized, the expression over time of the cognitive deficits, and in particular spatial memory deficits, is still debated. In this study we aimed at investigating spatial memory deficits and their recovery in a rat model of unilateral vestibular neurectomy (UVN), using a wide spectrum of behavioral tasks. In parallel, we analyzed markers of hippocampal plasticity involved in learning and memory. Our results indicate the UVN affects all domains of spatial memory, from working memory to reference memory and object-in-place recognition. These deficits are associated with long-lasting impaired plasticity in the ipsilesional hippocampus. These results highlight the crucial role of symmetrical vestibular information in spatial memory and contribute to a better understanding of the cognitive disorders observed in vestibular patients.

International audience; Acute peripheral vestibulopathy leads to a cascade of symptoms involving balance and gait disorders that are particularly disabling for vestibular patients. Vestibular rehabilitation protocols have proven to be effective in improving vestibular compensation in clinical practice. Yet, the underlying neurobiological correlates remain unknown. The aim of this study was to highlight the behavioural and cellular consequences of a vestibular rehabilitation protocol adapted to a rat model of unilateral vestibular neurectomy. We developed a progressive sensory-motor rehabilitation task, and the behavioural consequences were quantified using a weight-distribution device. This analysis method provides a precise and ecological analysis of posturolocomotor vestibular deficits. At the cellular level, we focused on the analysis of plasticity mechanisms expressed in the vestibular nuclei. The results obtained show that vestibular rehabilitation induces a faster recovery of posturolocomotor deficits during vestibular compensation associated with a decrease in neurogenesis and an increase in microgliogenesis in the deafferented medial vestibular nucleus. This study reveals for the first time a part of the underlying adaptative neuroplasticity mechanisms of vestibular rehabilitation. These original data incite further investigation of the impact of rehabilitation on animal models of vestibulopathy. This new line of research should improve the management of vestibular patients.

International audience; Pollen characters of the Algerian oleaster (Olea europaea subsp. europaea var. sylvestris [Mill.] Lehr) from eight ecotypes were analysed to evaluate the geo-climatic effect of their environment. Samples were collected along an altitudinal gradient from western to central Algeria. Eighteen morphological characters of the pollen grains were studied using scanning electron microscopy (SEM). The results show significant inter-populations variability. The geo-climatic conditions, duration and timing of dry periods vary from one area to another. Depending on the area, the length of the dry period (P p ≤ 2T) coincides more or less with anthesis periods. No significant geo-climatic effects on exine parameters were detected, except for lumina density (LD) and mean lumina diameter (Lm). However, polar axis (P), pollen size index (PSI) and pollen colpis length (PCL) were found to be related to latitude, longitude and temperature. LD and Lm were strongly linked to the pollen parameters, resulting in variation in pollen shape and size. Depending on the geo-climatic conditions, three morphotypes appear. The morphotype from a site with high temperature, low humidity associated with a long dry period is characterised by small pollen size, low lumina surface area and high lumina density/100 μm2 and vice versa. The results indicate that the exine has played an important role in the environmental adaption in these wild populations.

Fe 3 O 4 /Au core-shell nanoparticles have been prepared using reverse micelle synthesis with the aim of studying the traceability of blood vessels and allow biosensing through surface enhanced Raman spectroscopy. The shell provides protection against oxidation, plasmon properties and prevents aggregation of the magnetic nanoparticles. A solution of Fe 3 O 4 /Au core-shell nanoparticles in fluorescence has been injected into fresh ex-vivo animal tissues to check the traceability of blood vessels. Optical properties of the tissues in the UV-Vis-NIR have been explored on both fresh and injected tissues to prove the penetration of Raman excitation sources through the dermis and the entire sequence of the skin layers. Postbariatric surgery as well as rapid diagnosis on circulatory issues are examples of future applications.

Isoprene, the main volatile released by plants, is known to protect the photosynthetic apparatus in isoprene emitters submitted to oxidative pressures caused by environmental constraints. Whether ambient isoprene contributes to protect negligible plant emitters under abiotic stress conditions is less clear, and no study has tested if ambient isoprene is beneficial during drought periods in plant species that naturally release negligible isoprene emissions. This study examines the effect of exogenous isoprene (20 ppbv) on net photosynthesis, stomatal conductance and production of H2O2 (a reactive oxygen species: ROS) in leaves of Acer monspessulanum (a negligible isoprene emitter) submitted to three watering treatments (optimal, moderate water stress and severe water stress). Results showed that A. monspessulanum exhibited a net photosynthesis increase (+30%) and a relative leaf H2O2 decrease when saplings were exposed to an enriched isoprene atmosphere compared to isoprene-free conditions under moderate water deficit. Such physiological improvement under isoprene exposure was not observed under optimal watering or severe water stress. These findings suggest that when negligible isoprene emitters are surrounded by a very high concentration of isoprene in the ambient air, some plant protection mechanism occurs under moderate water deficit probably related to protection against ROS damage eventually impeding photosynthesis drop.

Several taxa of Stephanodiscaceae were found in the upper section of Pleistocene sediments from Lake Petén-Itzá (Guatemala). A new fossil genus Cyclocostis Paillès gen. nov. and new extant species Discostella gabinii Paillès & Sylvestre sp. nov. are described. Cyclocostis gen. nov. is characterized by a strongly tangentially undulated valve surface, coarse unequal striation reaching a central punctum in the valve center, an absence of central lamina and domed criba, widely open alveoli with one median recessed costa bearing marginal fultoportulae and a single rimoportula all within a ring. A single valve face fultoportula is present on the raised part of the valve opposite the rimoportula. Differences relative to similar genera and the delimitation of a new genus are discussed. Discostella gabinii sp. nov. is distinguished by circular and flat valves, a small central area bearing 5 to > 30 scattered large areolae giving a colliculate appearance, medium-sized alveoli, marginal fultoportulae on every 4–5th costa, a single rimoportula and internally smooth valve center. Differences to similar taxa in the genus Discostella are discussed. The succession of the species of Cyclotella, Discostella and Cyclocostis gen. nov. in our record could represent eco-phenotypic responses to particular environmental stress / change.

Isoprene, the main volatile released by plants, is known to protect the photosynthetic apparatus in isoprene emitters submitted to oxidative pressures caused by environmental constraints. Whether ambient isoprene contributes to protect negligible plant emitters under abiotic stress conditions is less clear, and no study has tested if ambient isoprene is beneficial during drought periods in plant species that naturally release negligible isoprene emissions. This study examines the effect of exogenous isoprene (20 ppbv) on net photosynthesis, stomatal conductance and production of H2O2 (a reactive oxygen species: ROS) in leaves of Acer monspessulanum (a negligible isoprene emitter) submitted to three watering treatments (optimal, moderate water stress and severe water stress). Results showed that A. monspessulanum exhibited a net photosynthesis increase (+30%) and a relative leaf H2O2 decrease when saplings were exposed to an enriched isoprene atmosphere compared to isoprene-free conditions under moderate water deficit. Such physiological improvement under isoprene exposure was not observed under optimal watering or severe water stress. These findings suggest that when negligible isoprene emitters are surrounded by a very high concentration of isoprene in the ambient air, some plant protection mechanism occurs under moderate water deficit probably related to protection against ROS damage eventually impeding photosynthesis drop.

Damage to cochlear primary afferent synapses has been shown to be a key factor in various auditory pathologies. Similarly, the selective lesioning of primary vestibular synapses might be an underlying cause of peripheral vestibulopathies that cause vertigo and dizziness, for which the pathophysiology is currently unknown. To thoroughly address this possibility, we selectively damaged the synaptic contacts between hair cells and primary vestibular neurons in mice through the transtympanic administration of a glutamate receptor agonist. Using a combination of histological and functional approaches, we demonstrated four key findings: (1) selective synaptic deafferentation is sufficient to generate acute vestibular syndrome with characteristics similar to those reported in patients; (2) the reduction of the vestibulo-ocular reflex and posturo-locomotor deficits mainly depends on spared synapses; (3) damaged primary vestibular synapses can be repaired over the days and weeks following deafferentation; and (4) the synaptic repair process occurs through the re-expression and re-pairing of synaptic proteins such as CtBP2 and SHANK-1. Primary synapse repair might contribute to re-establishing the initial sensory network. Deciphering the molecular mechanism that supports synaptic repair could offer a therapeutic opportunity to rescue full vestibular input and restore gait and balance in patients., Summary: The molecular rearrangements of the synaptic proteins that accompany the deafferentation and subsequent reafferentation of the inner ear sensors following an excitotoxic insult are demonstrated for the first time.

This work is part of a study focused on surface enhanced Raman scattering of biomolecules using magnetic-plasmonic nanostructured substrates. The substrates are nanostructured Fe 3 O 4 coated with Au and Ag, respectively. Fe 3 O 4 has an inverse spinel structure and a magnetic moment of 4.1µ B /f.u, a Curie temperature T C = 850 K and is a conductive oxide at room temperature. The Fe 3 O 4 nanocompound was prepared via green synthesis. Gold/silver nanocoatings were deposited by drop-cast from cyanide free solutions. The effect of the spin-plasmonic structures on the SERS effect is investigated through label free SERS measurements on traces of body fluids and submicron fragments of animal tissue. The enhancement factor is compared with that resulted from SERS experiments on twin samples deposited on Au and Ag nanostructured surfaces. We foresee applications in histopathology and forensics.

International audience; Triangular shapes have inspired scientists over time and are common in nature, such as the flower petals ofoxalis triangularis, or the triangular faces of tetrahedrite crystals or on the icosahedron faces of virus capsids. Supramolecular chemistry has enabled the construction of triangular assemblies, many of which possess functional features.Among these structures, cucurbiturils have been used to build supramolecular triangles and we recently reported paramagnetic - cucurbit[8]uril (CB[8]) triangles but reasons of their formation remain unclear. Several parameters have nowbeen identified to explain their formation. At first sight, the radical nature of the guest appeared of prime importance toget the triangles and we focused on extending this concept to biradicals for obtaining supramolecular hexaradicals. Twosodium ions were systematically observed by ESI-MS in trimer structures and the presence of Na+triggered or strengthened the triangulation of CB[8]:guest 1:1 complexes in solution. X-ray crystallography and molecular modelling have allowed proposing two plausible sites of residence for the two sodium cations. We then found that a diamagnetic guestwith an H bond acceptor function is equally good at forming CB[8] triangles. Hence, a guest molecule containing a ketonefunction has been precisely triangulated thanks to CB[8] and sodium cations as determined by DOSY-NMR and DLS. Abinding constant for the triangulation of 1:1, to 3:3 complexes, is proposed. This concept has finally been extended to thetriangulation of ditopic guests toward network formation by reticulation of CB[8] triangles using dinitroxide biradicals.

The generation of replacement inner ear hair cells (HCs) remains a challenge and stem cell therapy holds the potential for developing therapeutic solutions to hearing and balance disorders. Recent developments have made significant strides in producing mouse otic progenitors using cell culture techniques to initiate HC differentiation. However, no consensus has been reached as to efficiency and therefore current methods remain unsatisfactory. In order to address these issues, we compare the generation of otic and HC progenitors from embryonic stem (ES) cells in two cell culture systems: suspension vs. adherent conditions. In the present study, an ES cell line derived from an Atoh1-green fluorescent protein (GFP) transgenic mouse was used to track the generation of otic progenitors, initial HCs and to compare these two differentiation systems. We used a two-step short-term differentiation method involving an induction period of 5 days during which ES cells were cultured in the presence of Wnt/transforming growth factor TGF-β inhibitors and insulin-like growth factor IGF-1 to suppress mesoderm and reinforce presumptive ectoderm and otic lineages. The generated embryoid bodies were then differentiated in medium containing basic fibroblast growth factor (bFGF) for an additional 5 days using either suspension or adherent culture methods. Upon completion of differentiation, quantitative polymerase chain reaction analysis and immunostaining monitored the expression of otic/HC progenitor lineage markers. The results indicate that cells differentiated in suspension cultures produced cells expressing otic progenitor/HC markers at a higher efficiency compared with the production of these cell types within adherent cultures. Furthermore, we demonstrated that a fraction of these cells can incorporate into ototoxin-injured mouse postnatal cochlea explants and express MYO7A after transplantation. Copyright © 2016 John Wiley & Sons, Ltd.

Bulk polycrystalline MnGexSby materials doped with Co or Fe were prepared and investigated with the aim of obtaining new diluted magnetic semiconductor (DMS) materials. An innovative preparation method was also established. Investigation techniques like X-ray diffraction (XRD), Raman scattering, and scanning electron microscopy (SEM) associated with energy dispersive X-ray analysis (EDX) have been employed to derive the structural properties and the composition of the bulk material.

This work describes latent fluorescence particles (LFPs) based on a new environmentally sensitive carbazole compound aggregated in water and their use as sensors for probing various cavitands and the different stages of aggregating systems. Cyclodextrins (CDs), cucurbit[n]urils (CB[n], n = 6, 7, 8), and a resorcinarene capsule were used to study the dynamic nature of the LFPs. The fluorescence was dramatically enhanced by a proposed disaggregation-induced emission enhancement (DIEE) mechanism with specific features for CB[n]. Then, the aggregated states of the dipeptides Leu-Leu, Phe-Phe, and Fmoc-Leu-Leu (vesicles, crystals, fibers) were studied by fluorescence spectroscopy and confocal fluorescence microscopy thanks to the adaptive and emissive behavior of the LFPs, allowing us to study an interesting polymorphism phenomenon. The LFPs have then been used in the sensing of the aggregation of the polysaccharide alginate, for which distinct fluorescence turn-on is detected upon stepwise biopolymer assembly, and for amylose detection. The carbazole particles not only adapt to various environments but also display multicolor fluorescent signals. They can be used for the fast probing of the aggregation propensity of newly prepared molecules or biologically relevant compounds or to accelerate the discovery of new macrocycles or of self-assembling peptides in water.

International audience; Physical properties of carbonate rocks cannot be fully captured from laboratory-sized samples. Indeed, heterogeneous facies distribution and/or diagenetic alterations may lead to significant variations in petrophysical properties within few meters. In carbonates, diagenetic transformations are tightly related to nature of fluids flowing through the formations, e.g. via fractures network. Consequently, reservoir properties may have patchy distribution, and may not be correlatable (e.g. using facies distribution or wells-logs correlations) within few meters. Our works aim at characterizing carbonates anisotropy at different scales, and are subject of two presentations at SEG's 87th Annual Meeting. This abstract deals with the second part of our approach, that's to say characterizing impact of diagenetic alteration on reservoir properties and seismic anisotropy, from centimeter to multi-meter scale. This part of the works integrate data from centimeter-scale (mini-cores), decimeter-scale (5″ cores), multi-meter (ultrasonic crosshole), and hectometer-scale (seismic), which have been measured at suitable frequency ranges (1MHz, 250kHz, 50kHz, and 1–100Hz, respectively). Although anisotropy is measureable at every scales, its origins vary according to scale. In this study, it is shown that matrix of porous samples are weakly anisotropic as a result of inter-crystalline pores. At centimeter-scale, anisotropy can also be related to: (1) patchy distribution of some physical properties, (2) local cracks distribution, and (3) thick single fractures. The lack of correlation between stiffness components from seismic-scale measurements, and laboratory to multi-meter scale ones emphasizes the fact that, when fracturing dominates, measured anisotropy is dominated by fracture/fault related anisotropy and matrix-related anisotropy may be lost. So that, scale effect must be handled carefully in anisotropy analyses, especially for carbonate formations.This paper has been withdrawn from the Technical Program and will not be presented at the 87th SEG Annual Meeting.

International audience; The comparative study of plant polymorphism using plant taxonomic characters is underrated in Algeria, especially for species of the genus Juniperus L. The present work has been realized in order to look out for the existence of phenotypic variability among seven natural populations of Juniperus oxycedrus L. through a descriptive and comparative analysis of the needles, galbulus and stomata. The epidermal surfaces have also been investigated in order to better characterize this species. Twenty-three quantitative and qualitative morphological characters have been studied. The observation and evaluation of macro and micromorphological characters have been realized with binocular optical and scanning electronic microscopes. The variance analysis showed that the seven studied populations present a considerable morphological diversity at both intra- nd inter-population levels for the variables needles, galbulus and stomata, while the multivariate analysis allowed to separate all the studied populations into distinct groups according to their phenotypic characters, highlighting correlations between the morphological variables and the environmental characteristics. Otherwise, micro-morphological variations have been observed for the epidermal surfaces including a variation in the stomatal density, the size of stomata, the occurrence of epicuticular wax and changes in the epidermal structure.; L'étude comparative du polymorphisme des végétaux par le biais des caractères taxinomiques d'un végétal est insuffisamment prise en compte en Algérie, surtout pour les espèces du genre Juniperus L. Le présent travail a été réalisé afin de rechercher l'existence d'une variabilité phénotypique dans sept populations naturelles de Juniperus oxycedrus L. à l'aide d'une analyse descriptive et comparative des aiguilles, des galbules et des stomates. Les surfaces épidermiques ont été également examinées dans le but de mieux caractériser cette essence. Un total de vingt-trois caractères morphologiques, quantitatifs et qualitatifs, a été étudié. L'observation et l'évaluation des caractères macro-et micro-morphologiques ont été réalisées sous loupe binoculaire, au microscope optique et au microscope électronique à balayage. L'analyse de la variance montre que les sept populations étudiées présentent une diversité morphologique considérable aux niveaux intra-et inter-populationnels pour les variables aiguilles, galbules et stomates, tandis que l'analyse multivariée a permis de séparer l'ensemble des populations étudiées en groupes bien distincts selon leurs caractères phénotypiques en mettant en évidence des corrélations entre les variables morphologiques et les caractéristiques environnementales. Par ailleurs, des variations micro-morphologiques ont été observées pour les surfaces épidermiques, incluant une variation dans la densité stomatique, la taille des stomates, l'occurrence de cire épicuticulaire, et des modifications dans la structure de l'épiderme.

Morphological variability (needles, galbulus) among seven populations of the Juniperus oxycedrus L. species-complex in Algeria. The comparative study of plant polymorphism using plant taxonomic characters is underrated in Algeria, especially for species of the genus Juniperus L. The present work has been realized in order to look out for the existence of phenotypic variability among seven natural populations of Juniperus oxycedrus L. through a descriptive and comparative analysis of the needles, galbulus and stomata. The epidermal surfaces have also been investigated in order to better characterize this species. Twenty-three quantitative and qualitative morphological characters have been studied. The observation and evaluation of macro and micro-morphological characters have been realized with binocular optical and scanning electronic microscopes. The variance analysis showed that the seven studied populations present a considerable morphological diversity at both intra-and inter-population levels for the variables needles, galbulus and stomata, while the multivariate analysis allowed to separate all the studied populations into distinct groups according to their phenotypic characters, highlighting correlations between the morphological variables and the environmental characteristics. Otherwise, micro-morphological variations have been observed for the epidermal surfaces including a variation in the stomatal density, the size of stomata, the occurrence of epicuticular wax and changes in the epidermal structure., L’étude comparative du polymorphisme des végétaux par le biais des caractères taxinomiques d’un végétal est insuffisamment prise en compte en Algérie, surtout pour les espèces du genre Juniperus L. Le présent travail a été réalisé afin de rechercher l’existence d’une variabilité phénotypique dans sept populations naturelles de Juniperus oxycedrus L. à l’aide d’une analyse descriptive et comparative des aiguilles, des galbules et des stomates. Les surfaces épidermiques ont été également examinées dans le but de mieux caractériser cette essence. Un total de vingt-trois caractères morphologiques, quantitatifs et qualitatifs, a été étudié. L’observation et l’évaluation des caractères macro-et micro-morphologiques ont été réalisées sous loupe binoculaire, au microscope optique et au microscope électronique à balayage. L’analyse de la variance montre que les sept populations étudiées présentent une diversité morphologique considérable aux niveaux intra-et inter-populationnels pour les variables aiguilles, galbules et stomates, tandis que l’analyse multivariée a permis de séparer l’ensemble des populations étudiées en groupes bien distincts selon leurs caractères phénotypiques en mettant en évidence des corrélations entre les variables morphologiques et les caractéristiques environnementales. Par ailleurs, des variations micro-morphologiques ont été observées pour les surfaces épidermiques, incluant une variation dans la densité stomatique, la taille des stomates, l’occurrence de cire épicuticulaire, et des modifications dans la structure de l’épiderme., Hafsi Zakaria,Belhadj Safia,Derridj Arezki,Mévy Jean-philippe,Notonnier Roger,Tonetto Alain,Gauquelin Thierry. Étude de la variabilité morphologique (aiguilles, galbules) du complexe spécifique Juniperus oxycedrus l., le Genévrier oxycèdre, au sein de sept populations d’Algérie. In: Revue d'Écologie (La Terre et La Vie), tome 72, n°4, 2017. pp. 353-373.

Breast cancer frequency in human and other mammal female populations has worryingly increased lately. The acute necessity for taxonomy of the aetiological factors along with seeking for new diagnostic tools and therapy procedures aimed at reducing mortality have yielded in an intense research effort worldwide. Surgery is a regular method to counteract extensive development of breast cancer and prevent metastases provided that negative surgical margins are achieved. This highly technical challenge requires fast, extremely sensitive and selective discrimination between malignant and benign tissues even down to molecular level. The particular advantages of Raman spectroscopy, such as high chemical specificity, and the ability to measure raw samples and optical responses in the visible or near-infrared spectral range, have recently recommended it as a means with elevated potential in precise diagnostic in oncology surgery. This review spans mainly the latter 10 years of exceptional efforts of scientists implementing Raman spectroscopy as a nearly real-time diagnostic tool for clean margins assessment in mastectomy and lumpectomy. Although greatly contributing to medical discoveries for the wealth of humanity, animals as patients have benefitted less from advances in surgery diagnostic using Raman spectroscopy. This work also dedicates a few lines to applications of surface enhanced Raman spectroscopy in veterinary oncological surgery.

This paper shows some results of our work on the use of Surface Enhanced Raman Scattering as an ex vivo and in vivo diagnostic means in veterinary surgery and oncology. Also, as part of the involved research, interspecies discrimination of adipose constituents and body fluids is illustrated. These later outcomes would supply efficient instruments to forensics. An innovative system based on surface enhanced Raman scattering, primarily used in small animal surgery, will add to the ongoing research on tumour margin assessment. Samples from animal patients following therapeutic mastectomy have been investigated ex vivo using a LABRAM HR 800 micro-Raman spectrometer. Spectra were collected from 100 cm−1 to 4000 cm−1 using a 632 nm HeNe laser, which to date has been reported on in vitro human samples only. A surface enhanced Raman effect of up to 107 has been obtained on areas of surgery instruments either raw or coated with silver or gold. This dramatically improves spectral resolution and reduces the accumulation time down to 60 s, which would allow for real time diagnostic.

Reactive cell proliferation occurs rapidly in the cat vestibular nuclei (VN) after unilateral vestibular neurectomy (UVN) and has been reported to facilitate the recovery of posturo-locomotor functions. Interestingly, whereas animals experience impairments for several weeks, extraordinary plasticity mechanisms take place in the local microenvironment of the VN: newborn cells survive and acquire different phenotypes, such as microglia, astrocytes, or GABAergic neurons, whereas animals eventually recover completely from their lesion-induced deficits. Because brain-derived neurotrophic factor (BDNF) can modulate vestibular functional recovery and neurogenesis in mammals, in this study, we examined the effect of BDNF chronic intracerebroventricular infusion versus K252a (a Trk receptor antagonist) in our UVN model. Results showed that long-term intracerebroventricular infusion of BDNF accelerated the restoration of vestibular functions and significantly increased UVN-induced neurogenesis, whereas K252a blocked that effect and drastically delayed and prevented the complete restoration of vestibular functions. Further, because the level of excitability in the deafferented VN is correlated with behavioral recovery, we examined the state of neuronal excitability using two specific markers: the cation-chloride cotransporter KCC2 (which determines the hyperpolarizing action of GABA) and GABA(A) receptors. We report for the first time that, during an early time window after UVN, significant BDNF-dependent remodeling of excitability markers occurs in the brainstem. These data suggest that GABA acquires a transient depolarizing action during recovery from UVN, which potentiates the observed reactive neurogenesis and accelerates vestibular functional recovery. These findings suggest that BDNF and/or KCC2 could represent novel treatment strategies for vestibular pathologies. SIGNIFICANCE STATEMENT In this study, we report for the first time that brain-derived neurotrophic factor potentiates vestibular neurogenesis and significantly accelerates functional recovery after unilateral vestibular injury. We also show that specific markers of excitability, the potassium-chloride cotransporter KCC2 and GABA(A) receptors, undergo remarkable fluctuations within vestibular nuclei (VN), strongly suggesting that GABA acquires a transient depolarizing action in the VN during the recovery period. This novel plasticity mechanism could explain in part how the system returns to electrophysiological homeostasis between the deafferented and intact VN, considered in the literature to be a key parameter of vestibular compensation. In this context, our results open new perspectives for the development of therapeutic approaches to alleviate the vestibular symptoms and favor vestibular function recovery.

International audience; Atractylis serratuloides is an abundant native spiny species that grows in the surroundings of superphosphate factories in Tunisia. This plant species is adapted to arid environments and tolerates a high level of fluoride pollution in soils. The aim of this study was to better understand the physiological mechanisms of fluoride tolerance of this species, comparing the fluoride-contaminated sites of Gabes and Skhira with the reference site of Smara. Results demonstrated the involvement of leaf element and phytometabolite balances in the in situ response of A. serrulatoides to fluoride. Calcium, sulphur and magnesium were differently distributed between the sites of Gabes and Smara in all plant organs. No specific tissue fluorine accumulation in root, stem and leaf, even in the most contaminated site at Gabes, was detected by EDAX mapping. Lower anthocyan and flavonol levels but enhanced nitrogen balance index were found in A. serrulatoides leaves from Gabes compared to the two other sites. A. serratuloides appeared as a fluoride excluder and its tolerance involved calcium interactions with fluoride. Moreover, an occurrence of dark septate endophytes and arbuscular mycorhizal fungi in root systems of A. serratuloides was reported for the first time, and these symbioses were present but low at all sites. We suggest the use of this plant species for fluoride-polluted soil stabilization.

International audience; In the field of keratoconus treatment, a lipid-based liquid crystal nanoparticles system has been developed to improve the preocular retention and ocular bioavailability of riboflavin, a water-soluble drug. The formulation of this ophthalmic drug delivery system was optimized by a simplex lattice experimental design. The delivery system is composed of three main components that are mono acyl glycerol (monoolein), poloxamer 407 and water and two secondary components that are riboflavin and glycerol (added to adjust the osmotic pressure). The amounts of these three main components were selected as the factors to systematically optimize the dependent variables that are the encapsulation efficiency and the particle size. In this way, 12 formulas describing experimental domain of interest were prepared. Results obtained using small angle X-rays scattering (SAXS) and cryo-transmission electron microscopy (cryo-TEM) evidenced the presence of nano-objects with either sponge or hexagonal inverted structure. In the zone of interest, the percentage of each component was determined to obtain both high encapsulation efficiency and small size of particles. Two optimized formulations were found: F7 and F1. They are very close in the ternary phase diagram as they contain 6.83% of poloxamer 407; 44.18% and 42.03% of monoolein; 46.29% and 48.44% of water for F7 and F11, respectively. These formulations displayed a good compromise between inputs and outputs investigated.

International audience; During the last deglaciation, the Bolivian Altiplano (15e23 S, 66e70 W) was occupied by paleolake Tauca covering, at least, ~51,000 km 2 at its maximum highstand between 16.5 and 15 ka. Twenty-five hundred years later, after a massive regression, a new transgressive phase, produced paleolake Coi-pasa, smaller than Tauca and restricted to the southern part of the basin. These paleolakes were overlooked at the west by the Sajama ice cap. The latter provides a continuous record of the oxygen isotopic composition of paleo-precipitation for the last 25 ka. Contemporaneously to the end of paleolake Tauca, around 14.3 ka, the Sajama ice cap recorded a significant increase in ice oxygen isotopic composition (d 18 O ice). This paper examines to what extent the disappearance of Lake Tauca contributed to precipitation on the Sajama summit and this specific isotopic variation. The water d 18 O values of paleolakes Tauca and Coipasa (d 18 O lake) were quantitatively reconstructed from 18.5 to 11.7 ka based on diatom isotopic composition (d 18 O diatoms) and ostracod isotopic composition (d 18 O carbonates) retrieved in lacus-trine sediments. At a centennial time scale, a strong trend appears: abrupt decreases of d 18 O lake during lake fillings are immediately followed by abrupt increases of d 18 O lake during lake level stable phases. The highest variation occurred at ~15.8 ka with a d 18 O lake decrease of about ~10‰, concomitant with the Lake Tauca highstand, followed ~400 years later by a 7‰ increase in d 18 O lake. A simple hydro-isotopic modeling approach reproduces consistently this rapid "decreaseeincrease" feature. Moreover, it suggests that this unexpected re-increase in d 18 O lake after filling phases can be partly explained by an equilibration of isotopic fluxes during the lake steady-state. Based on isotopic calculations during lake evaporation and a simple water stable isotopes balance between potential moisture sources at Sajama (advection versus lake evaporation), we show that total or partial evaporation (from 5 to 60%) of pale-olake Tauca during its major regression phase at 14.3 ka could explain the pronounced isotopic excursion at Sajama ice cap. These results suggest that perturbations of the local hydrological cycle in lacustrine areas may substantially affect the paleoclimatic interpretation of the nearby isotopic signals (e.g. ice core or speleothems).

International audience; Elements uptake, histological distributions as well as mycorrhizal and physiological statuses of Atriplex halimus were determined on trace metal and metalloid polluted soils from the surrounding spray zones of a former lead smelter in the South-East coast of Marseille (France). Analyses of heavy metal and arsenic distribution in soil and plant organs showed that A. halimus tolerance is largely due to exclusion mechanisms. No specific heavy metal concentration in leaf or root tissues was observed. However, accumulation of salts (NaCl, KCl, Mg and Ca salts) on leaf bladders and peripheral tissues of roots was observed and may compete with metal element absorption. Occurrence of endomycorrhizal structures was detected in roots and may contribute to lower element transfer from root into the aerial parts of plants. The non-destructive measurements of leaf epidermal chlorophylls, flavonols and phenols showed a healthy state of the A. halimus population on the metal and metalloid polluted sites. Considering the low metal bioaccumulation and translocation factors along with a reduced metal stress diagnosis, A. halimus appeared as a good candidate for phytostabilization of trace metals and metalloids and notably arsenic in contaminated soils of the Mediterranean spray zone. However, its invasive potential has to be determined before an intensive in situ use.

Films of the material systems ZnSnSb and MnGeSb doped with Fe and Co respectively have been grown by pulsed laser deposition on silicon. Room temperature Hall effect measurements show that all Fe-doped PLD films are n-type whereas MnGeSb:Co ones are p-type. Carrier concentrations vary with film thickness, resulting in ∼10 17 –10 18 cm −3 for ZnSnSb:Fe and ∼10 20 –10 21 cm −3 for MnGeSb:Co films. Carrier mobilities are of the order 10 2 cm 2 /Vs in the MnGeSb:Co films and between 10 2 and 10 3 cm 2 /V s in ZnSnSb:Fe. Curie points above room temperature have been found for samples of both material systems.

Summary form only given. We present a review of the research carried out during the past six months by groups from Romania, Victoria University of Wellington, New Zealand, and Universite de Provence, Marseille, France, with the aim to fabricate photonic materials within the framework of the COST ACTION P11. Novel aluminophosphate glasses doped with semiconductors (CdSSe) have been produced, whose transmission in the visible and Raman spectra have been investigated. We have noticed that transmission edge and the spectra shape depend on the crystallites' dimensions. The fluorescence is relatively narrow (0.12-0.15 eV) suggesting reasonably well-ordered crystallites with reasonably uniform diameters. Another attempt of the groups to find a way of producing quasi-periodic, at this stage, features, in amorphous materials, consists of annealing studies on amorphous GaN thin films (150 nm) on silicon. The annealing processes have been carried out using the hot stage of an electronic microscope (SEM), so that real time observation has been possible. Following the annealing, the GaN films have developed hemispherical structures uniformly distributed over the entire surface of the sample. Apparently, those structures are denser than the surrounding film, and EDX analysis shows that they conserved the initial composition of the film. At the necked eye the colour of the sample changed from blue to yellow.

Amorphous and nanocrystalline group III nitrides can be formed with relative ease in comparison with fully single crystalline material, and they show at least some properties in common with the crystalline form. Here we report experiments with the preparation of these materials, focussing especially on the potential to form patterned films with structures whose dimensions are comparable to visible wavelengths. There are clear opportunities to form both self-assembled and controlled patterns.

The effects of thermal annealing on structural and optical properties of amorphous GaN thin films obtained by Ion Assisted Deposition (IAD) have been investigated. Thermal annealing. was carried out in flowing nitrogen and respectively under water vapour pressure (1.7-2.4 torr), at temperatures up to 800/spl deg/C. From SEM observations of the annealing processes in real time it appears that formation of nano-crystallites in the amorphous environment occurs at about 400/spl deg/C. XRD and Raman scattering performed on the annealed films prove the presence of nano-crystallites (2-4 nm). Optical measurements show a weak absorption edge in the as prepared film, and the deepening edge and reduced sub-band absorption after annealing.

International audience; Influence of aridity on fungal arbuscular mycorrhizal variation in five natural Algerian populations of the Atlas Pistachio (Pistacia atlantica Desf.).-Because of its powerful rooting system, Atlas pistachio tree plays an important role against soil erosion and desertification which constantly threatens the arid and Saharan regions. In this work, the variation of mycorrhization parameters (mycorrhizal rate, colonization intensity, arbuscular and vesicular content) are studied according to the seasonal and bioclimates variation, in order to understand the best conditions for the establishment of the symbiosis in this species. The physico-chemical properties of soils (pH, electric conductivity, organic matter and total limestone amount) were determined for five sampling sites. Spores harvested fungi from the rhizosphere area were morphologically identified, and the specific diversity of mycorrhizal fungi was measured in the different sites. Microscopic observations of the roots revealed the presence of arbuscular mycorrhizal fungi (AMF). The frequency of mycorrhization and the intensity of colonization are higher in the arid bioclimate, characterized by alkaline soils, low organic matter with relatively low levels of calcium carbonates. A total of 19 species of mycorrhizal fungi has been isolated. This set is dominated by two families (Gigasporaceae and Glomeraceae) but the most common genus is Gigaspora. Analysis of Variance (bioclimate factor and bioclimate x season interaction) showed a very significant difference for the frequency of mycorrhization and highly significant difference for soil variables. The Fisher (LSD) test revealed the presence of heterogeneous groups for all studied parameters except for the vesicle amount. PCA, as well, showed an aridity gradient on the first axis and a thermic gradient on the second one.; Grâce à son système racinaire très puissant, le Pistachier de l'Atlas joue un rôle important contre l'érosion des sols et dans la lutte contre la désertification qui menace constamment les régions arides et sahariennes. On se propose ici d'étudier la variation des paramètres de mycorhization (fréquence de mycorhization, intensité de colonisation, teneur arbusculaire et vésiculaire) en fonction des saisons et des stations (caractérisées par leur bioclimats), afin de mieux cerner les conditions de l'établissement de la symbiose chez cette espèce. Les propriétés physico-chimiques (pH, conductivité électrique, matière organique et calcaire total) des sols ont été déterminées pour cinq sites d'échantillonnage. Des spores de champignons récoltées dans la rhizosphère de l'espèce étudiée ont fait l'objet d'une identification morphologique afin de mesurer la diversité des espèces de champignons mycorhiziens. Les observations microscopiques des racines ont révélé la présence de champignons mycorhiziens arbusculaires (CMA). La fréquence de mycorhization et l'intensité de colonisation sont plus importantes dans le bioclimat aride, caractérisé par des sols alcalins, pauvres en matière organique avec des taux relativement faibles en carbonates de calcium. Un total de 19 espèces de champignons mycorhiziens a été isolé. Cet ensemble est dominé par deux familles (Gigasporaceae et Glomeraceae) et le genre Gigaspora. L'analyse de la variance (facteur station et l'interaction station x saison) montre une différence très significative pour la fréquence de mycorhization et hautement significative pour les variables du sol. Le test Fisher (LSD) a révélé la présence de groupes hétérogènes pour tous les paramètres étudiés, excepté pour la teneur vésiculaire. Concernant l'ACP, celle-ci traduit un gradient d'aridité croissant, sur l'axe 1 et un gradient thermique hivernal croissant sur l'axe 2.