230 research outputs found
Aquaporins in the brain: from aqueduct to "multi-duct”
The aquaporin channel family was first considered as a family of water channels, however it is now clear that some of these channels are also permeable to small solutes such glycerol, urea and monocarboxylates. In this review, we will consider AQP4 and AQP9 expressed in the rodent brain. AQP4 is present on astrocytic end-feet in contact with brain vessels and could be involved in ionic homeostasis. However, AQP4 may also be involved in cell adhesion. AQP4 expression is highly modified in several brain disorders and it can play a key role in the cerebral edema formation. However, the exact role of AQP4 in edema formation is still debated. Recently, AQP4 has been shown to be also involved in astrocyte migration during glial scar formation. AQP9 is expressed in astrocytes and in catecholaminergic neurons. Two isoforms of AQP9 are expressed in brain cells, the shortest isoform is localized in the inner membrane of mitochondria and the longest in the cell membrane. The level of expression of AQP9 is negatively regulated by high concentrations of insulin. Taken together, these results suggest that AQP9 could be involved in brain energy metabolism. The induction of AQP9 in astrocytes is observed with time after stroke onset suggesting participation in the clearance of excess lactate in the extracellular space. These recent exciting results suggest that AQPs may not only be involved in water homeostasis in the brain but could also participate in other important physiological function
Improvement in real time detection and selectivity of phthalocyanine gas sensors dedicated to oxidizing pollutants evaluation
International audienceA sensor microsystem prototype, using copper phthalocyanine thin film as sensitive layer, and dedicated to ozone evaluation, was developed. The methodology implemented is based on cyclic sensor recalibrations by thermal cleaning of the sensitive membrane, and on pollutant concentration quantification according to the kinetics of sensor response. Results of laboratory experiments for various NO2 and O3 concentrations, in the range of 10–200 ppb, illustrate the selectivity of CuPc sensors towards ozone, obtained by our methodology. We have shown that ozone selectivity is especially improved for short time of exposure (few minutes) and for phthalocyanine layer maintained at low temperature (80 °C). For optimal conditions, our microsystem exhibits a threshold lower than 10 ppb, a resolution lower than 10 ppb, and good reproducibility of measurements. Performances obtained in real urban atmosphere are satisfying to ensure real time evaluation of ozone during several days. Long-term stability and the detection of NO2 by associating chemical filters to our microsystem will be also discussed
Classification non supervisée d'un graphe de co-expression avec des méta-données pour la détection de micro-ARNs
National audienceNous présentons dans cet article une méthode de classification non supervisée de sommets d'un graphe qui est utilisée dans un contexte biologique particulier. La problématique est de détecter de manière non supervisée des micro-ARNs probables. Pour ce faire, nous utilisons une approche multi-noyaux permettant d'intégrer des informations sur le graphe de co-expression et des informations supplémentaires sur les sommets de ce graphe. Cette approche est rendue robuste par une technique de bagging de classifications. Les résultats obtenus donnent des groupes de miRNAs potentiels dont certains permettent de discriminer avec une bonne confiance les vrais miRNAs des faux positifs
Effect of carbonation on the hydro-mechanical properties of Portland cements
International audienceWe evaluate experimentally the effect of carbonation on the hydro-mechanical properties of Portland cement. Samples were carbonated at 90 °C and 28 MPa under wet supercritical CO2. Two types of carbonation features were achieved, either the samples were homogeneously carbonated or they displayed sharp carbonation fronts. Using a tri-axial apparatus, the static elastic moduli and the mechanical strength were measured at in-situ pressure conditions (28 MPa) and showed a degradation of the mechanical properties of the samples where a carbonation front prevailed. Water and gas permeabilities were measured and showed that the samples with a carbonation front exhibit a stress sensitive permeability. P and S elastic wave velocities were measured to evaluate dynamic (ultrasonic range, 1 MHz) elastic moduli. The use of an effective medium theory approach enabled us to characterize the density and distribution of cracks within the samples. This approach outlines that the samples which developed a carbonation front were damaged
Comparative Dissociation of Peptide Polyanions by Electron Impact and Photo-Induced Electron Detachment
We compare product-ion mass spectra produced by electron detachment dissociation (EDD) and electron photodetachment dissociation (EPD) of multi-deprotonated peptides on a Fourier transform and a linear ion trap mass spectrometer, respectively. Both methods, EDD and EPD, involve the electron emission-induced formation of a radical oxidized species from a multi-deprotonated precursor peptide. Product-ion mass spectra display mainly fragment ions resulting from backbone cleavages of Cα–C bond ruptures yielding a and x ions. Fragment ions originating from N–Cα backbone bond cleavages are also observed, in particular by EPD. Although EDD and EPD methods involve the generation of a charge-reduced radical anion intermediate by electron emission, the product ion abundance distributions are drastically different. Both processes seem to be triggered by the location and the recombination of radicals (both neutral and cation radicals). Therefore, EPD product ions are predominantly formed near tryptophan and histidine residues, whereas in EDD the negative charge solvation sites on the backbone seem to be the most favorable for the nearby bond dissociation
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Validation of the French Version of the Child Post-Traumatic Stress Reaction Index: Psychometric Properties in French Speaking School-Aged Children
Background: Although the reliable and valid Child Post-Traumatic Stress Reaction Index (CPTS-RI) is a widely used measure of posttraumatic stress disorder (PTSD) symptoms in children, it has not been validated in French-speaking populations. The present study aims to assess the psychometric properties of the CPTS-RI in three samples of French-speaking school-children. Methods: Data was obtained from three samples. Sample 1 was composed of 106 children (mean (SD) age = 11.7(0.7), 50% females) victims of an industrial disaster. Sample 2 was composed of 50 children (mean (SD) age = 10.8(2.6), 44% females) who had received an orthopaedic surgical procedure after an accident. Sample 3 was composed of 106 children (mean (SD) age = 11.7(2.2), 44% females) admitted to an emergency department after a road traffic accident. We tested internal consistency using Cronbach's alpha. We examined test-retest reliability using intraclass correlation coefficient. In order to assess the convergent validity of the French version of the CPTS-RI and the Clinician Administered PTS Scale-Child and Adolescent (CAPS-CA), spearman-correlation coefficient was computed. To verify the validity of the cut-off scores, a ROC curve was constructed which evaluated the sensitivity and specificity of each score compared to the diagnosis with the CAPS-CA. We also used principal components analysis with varimax rotation to study the structure of the French version of the CPTS-RI. Results: Cronbach's alpha coefficient was 0.87 for the French version of the CPTS-RI. Two-week test-retest intraclass correlation coefficient (n = 30) was 0.67. The French version of the CPTS-RI was well correlated with the CAPS-CA (r = 0.76, p24 for the CPTS-RI, the sensitivity and specificities were 100% and 62.6%, respectively. The French version of the CPTS-RI demonstrated a three-factor structure. Conclusions: The CPTS-RI is reliable and valid in French-speaking children
Electrodes Modification Based on Metal-Free Phthalocyanine: Example of Electrochemical Sensors for the Detection of Acetic Acid
Electroanalytical properties of tetra-tert-butyl phthalocyanine (PcH 2 -tBu) modified electrodes are studied by cyclic voltammetry (CV). The modified electrodes are obtained by CV deposition techniques on gold (Au) and glassy carbon (C) screenprinted electrodes (SPEs) and used for the electrochemical detection of acetic acid (AA). Based on the CV experiments, the electrodeposition mechanism is detailed. The modified PcH 2 -tBu electrodes reveal one oxidation and one reduction peak within the potential window of the working electrodes. In the presence of the analyte (acetic acid), the modified electrodes show sensitivity in the range of 10 mM to 400 mM. For the PcH 2 -tBu modified Au electrode, a limit of detection (LOD) of 5.89 mM (based on the +0.06 V peak) was obtained while for the PcH 2 -tBu modified C electrode a LOD of 17.76 mM (based on the +0.07 V peak) was achieved. A signal decay of 17%, based on 20 experiments, is obtained when gold is used as working electrode. If carbon is used as working electrode a value of 7% is attained. A signal decay is observed after more than 50 cycles of experiments and is more pronounced when higher concentrations of acetic acid are used. A mechanism of sensing is proposed at the end
Sous les scories, une nécropole : un petit ensemble funéraire du Haut-Empire (Coulans-sur-Gée, « Les Brochardières », Sarthe)
Localisée en périphérie de la commune de Coulans-sur-Gée, à environ quinze kilomètres à l’ouest du Mans, la parcelle ZS 37 au lieu-dit « Les Brochardières » était jusqu’à récemment vouée au pâturage. La fouille qui s’est déroulée entre le 27 février et le 15 mars 2012 a permis de mettre au jour une nécropole à crémations partiellement conservée, installée le long d’une limite parcellaire d’origine probablement antique (matérialisée par une haie ou un chemin). Quatre dépôts ont été clairement identifiés, datés du courant du iie siècle de notre ère jusqu’au début du iiie siècle par le mobilier céramique. L’organisation interne et le matériel issu des fosses présentent une grande diversité. Les dépôts sont de type mixte et/ou en ossuaire, dans des fosses probablement couvertes, ayant ménagé un espace vide. Les céramiques sont d’origine locale, seule une forme témoigne de l’existence de vaisselle importée. Par la suite, un atelier de réduction directe du minerai de fer a été installé vers le milieu du iiie siècle de notre ère au bord du parcellaire préexistant, comprenant une aire de calcination, un bas fourneau et un amas de scories, le tout arasé. À une date indéterminée, une partie de ces vestiges a servi à exhausser la bande de roulement du chemin proche.About 15 kms from the french city of Le Mans, a partially preserved necropolis with cremations was found in 2012 along a plot of land probably inherited from the Roman period. Four graves have been identified, dated from the IInd to the beginning of the IIIrd century thanks to the pottery. Internal organisation and artefacts from those pits are very diversified. Deposits are of different types : ossuaries, pyre debris being redeposited, and deposits which includes both of the previous types. Pottery-wares used to place the ossuary, as well as the vessels deposited in the structures are from local origin, only one was imported. Afterwards, a steel industry settled in the mid IIIrd century.Im Jahr 2012 wurde rund 15 km westlich der französischen Stadt Le Mans eine teilweise erhaltene römische Nekropole mit Brandbestattungen nachgewiesen. Das betroffene Flurstück ZS 37 in der Flur „Les Brochardières“ war erst jüngst zur Beweidung freigegeben worden. Die Ausgrabung des Gräberfeldes fand vom 27 Februar bis zum 15 März 2012 statt. Sie hat gestattet, ein teilweise erhaltenes Brandgräberfeld freizulegen, das entlang einer durch eine Hecke oder einen Weg markierten Flurstücksgrenze angelegt worden war. Diese reicht vermutlich in die römische Zeit zurück. Vier Grabdeponierungen konnten eindeutig identifiziert werden. Sie können durch die Keramikfunde einem Zeitraum vom 2. bis zum frühen 3. Jh. n. Chr. zugewiesen werden. Die Bestattungssitten sowie das Fundmaterial aus den Grabgruben zeichnen sich durch große Diversität aus. Bei den Grabdeponierungen treten verschiedene Typen auf: Leichenbranddeponierungen sowie Brandschüttungen oder eine Mischung beider Bestattungssitten. Diese wurden in abgedeckten Gruben beigesetzt, bei denen offenbar stets ein Hohlraum erhalten blieb. Die Grabkeramik wurde dazu genutzt, den Leichenbrand zu deponieren. Die Keramikformen verweisen auf lokale Produktion; eine einzige Keramikform belegt auf das Auftreten von Importkeramik. Außerdem wurde ein Werkplatz entdeckt, an dem Roheisen verarbeitet wurde. Er wurde im Laufe des 3. Jahrhunderts n. Chr. am Rande des bereits existierenden Flurstücks angelegt und umfasste einen Röstplatz, einen Rennofen und eine Schlackenhalde, die jedoch alle bereits erodiert waren. Zu einem nicht näher bestimmbaren Zeitpunkt diente ein Teil dieser Hinterlassenschaften offenbar dazu, die Fahrbahn des nahegelegenen Weges zu erhöhen
Corticotectal Projections From the Premotor or Primary Motor Cortex After Cortical Lesion or Parkinsonian Symptoms in Adult Macaque Monkeys: A Pilot Tracing Study
The corticotectal projections, together with the corticobulbar (corticoreticular) projections, work in parallel with the corticospinal tract (CST) to influence motoneurons in the spinal cord both directly and indirectly via the brainstem descending pathways. The tectospinal tract (TST) originates in the deep layers of the superior colliculus. In the present study, we analyzed the corticotectal projections from two motor cortical areas, namely the premotor cortex (PM) and the primary motor cortex (M1) in eight macaque monkeys subjected to either a cortical lesion of the hand area in M1 (n = 4) or Parkinson’s disease-like symptoms PD (n = 4). A subgroup of monkeys with cortical lesion was subjected to anti-Nogo-A antibody treatment whereas all PD monkeys were transplanted with Autologous Neural Cell Ecosystems (ANCEs). The anterograde tracer BDA was used to label the axonal boutons both en passant and terminaux in the ipsilateral superior colliculus. Individual axonal boutons were charted in the different layers of the superior colliculus. In intact animals, we previously observed that corticotectal projections were denser when originating from PM than from M1. In the present M1 lesioned monkeys, as compared to intact ones the corticotectal projection originating from PM was decreased when treated with anti-Nogo-A antibody but not in untreated monkeys. In PD-like symptoms’ monkeys, on the other hand, there was no consistent change affecting the corticotectal projection as compared to intact monkeys. The present pilot study overall suggests that the corticotectal projection is less affected by M1 lesion or PD symptoms than the corticoreticular projection previously reported in the same animals
Acceptability and Feasibility of the Telehealth Bariatric Behavioral Intervention to Increase Physical Activity: Protocol for a Single-Case Experimental Study
Background:
Regular physical activity (PA) is recommended to optimize weight and health outcomes in patients who have undergone metabolic and bariatric surgery (MBS). However, >70% of patients have low PA levels before MBS that persist after MBS. Although behavioral interventions delivered face-to-face have shown promise for increasing PA among patients who have undergone MBS, many may experience barriers, preventing enrollment into and adherence to such interventions. Delivering PA behavior change interventions via telehealth to patients who have undergone MBS may be an effective strategy to increase accessibility and reach, as well as adherence.
Objective:
This paper reports the protocol for a study that aims to assess the feasibility and acceptability of the protocol or methods and the Telehealth Bariatric Behavioral Intervention (TELE-BariACTIV). The intervention is designed to increase moderate-to-vigorous intensity PA (MVPA) in patients awaiting bariatric surgery and is guided by a multitheory approach and a patient perspective. Another objective is to estimate the effect of the TELE-BariACTIV intervention on presurgical MVPA to determine the appropriate sample size for a multicenter trial.
Methods:
This study is a multicenter trial using a repeated (ABAB’A) single-case experimental design. The A phases are observational phases without intervention (A1=pre-MBS phase; A2=length personalized according to the MBS date; A3=7 months post-MBS phase). The B phases are interventional phases with PA counseling (B1=6 weekly pre-MBS sessions; B2=3 monthly sessions starting 3 months after MBS). The target sample size is set to 12. Participants are inactive adults awaiting sleeve gastrectomy who have access to a computer with internet and an interface with a camera. The participants are randomly allocated to a 1- or 2-week baseline period (A1). Protocol and intervention feasibility and acceptability (primary outcomes) will be assessed by recording missing data, refusal, recruitment, retention, attendance, and attrition rates, as well as via web-based acceptability questionnaires and semistructured interviews. Data collected via accelerometry (7-14 days) on 8 occasions and via questionnaires on 10 occasions will be analyzed to estimate the effect of the intervention on MVPA. Generalization measures assessing the quality of life, anxiety and depressive symptoms, and theory-based constructs (ie, motivational regulations for PA, self-efficacy to overcome barriers to PA, basic psychological needs satisfaction and frustration, PA enjoyment, and social support for PA; secondary outcomes for a future large-scale trial) will be completed via web-based questionnaires on 6-10 occasions. The institutional review board provided ethics approval for the study in June 2021.
Results:
Recruitment began in September 2021, and all the participants were enrolled (n=12). Data collection is expected to end in fall 2023, depending on the MBS date of the recruited participants.
Conclusions:
The TELE-BariACTIV intervention has the potential for implementation across multiple settings owing to its collaborative construction that can be offered remotely
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