Using relationships as a tool: early childhood educators’ perspectives of the child–caregiver relationship in a childcare setting

Children's early years are critical for development and many children access out-of-home care during this time. Services offering high-quality childcare afford an opportunity to impact positively on children's development, including acquisition of communication skills. A strong, responsive relationship between child and carer is important in facilitating children's communication development. For infants who are not yet verbal, early childhood educators (ECEs) need to be highly sensitive to the child's communication, and they need to develop a relationship with the child to interpret their signals and facilitate their communication. This study investigated the perspectives of ECEs on their relationships with infants in their care. Individual semi-structured interviews with ECEs were conducted and the interview data were triangulated with videoed observational data. The results demonstrate that these ECEs use the relationship with the children in their care as a tool for provision of optimal learning experiences across multiple developmental domains

Peptide labeling with metals using MS detection and optimization of metalloprotein extraction procedures in biological samples with proteomic purposes

Ce travail a développé une nouvelle méthode pour l'identification et la quantification des peptides, par l'optimisation de certaines stratégies disponibles appropriées pour le marquage des peptides avec des métaux lanthanide, une séparation par nano-HPLC et détection UV, et suivi par MALDI MS. Tout d'abord, les peptides ont été marqués avec les trois métaux lanthanides différents et un réactif fonctionnel - DOTA. Les résultats montrent que la réaction de transformation en dérivé à l'aide du réactif chélateur DOTA-NHS-ester a été efficace pour des peptides individuels et des mélanges de peptides, vérifiées à partir de la relation m/z obtenue par MALDI MS. L'application optimisée d un complexe (Cytochrome C digest) a montré des résultats comparables à ceux obtenus avec des peptides modèles. En parallèle, nous avons effectué l optimisation pour la purification de métalloprotéine dans la bile de poisson, qui est signalée entant que biomarqueurs de contamination métallique de l'environnement. Des procédures différentes (différents moments de centrifugation et différentes températures de traitement thermique) et les agents (DTT, b-mercaptoéthanol et TCEP) réduisant ont été apliqués pour purifier les MT isolées de la bile et du foie des poissons (Oreochromis niloticus). Des analyses spectrophotométriques ont été utilisées pour quantifier les échantillons de MT, et le gel SDS-PAGE a été utilisé pour évaluer qualitativement les différents résultats de la procédure. Chaque procédure a en suíte été évaluée statistiquement, une méhtode des surfaces de réponse a été appliquée. Les MT de la bile semblent être plus adéquate pour la surveillance de l'environnement en ce qui concerne l'exposition récente à des xénobiotiques qui peuvent influer sur l'expression protéomique et metalloproteomique de cette matrice biologique. Une procédure d exposition à des métaux dans le laboratoire a montré que les métaux étaient significativement importante pour l évaluation de la contamination à partir de la quantification de MT, selon le traitement de données par une techinique de réseau neural.This work developed a new method for the identification and quantification of peptides, by optimizing some of the available strategies suitable for labeling peptides with lanthanide metals with subsequent separation by nano-HPLC with UV detection, matrix-assisted laser desorption ionization-mass spectrometry (MALDI MS). First, peptides were labeled with the three different lanthanide metals using a functional DOTA-based reagent. The results demonstrate that the derivatization reaction using the chelating reagent DOTA-NHS-ester was effective for single peptides and peptide mixtures, verified from the m/z relation obtained by MALDI MS. The application of the optimized method in a more complex matrix (Cytochrome C digest) showed results comparable to those obtained with model peptides. In parallel, environmental analyses were conducted, by performing the standardization of metalloprotein purification in fish bile, since this matrix has been reported as a biomarker for environmental metal contamination. Different procedures (varying centrifugation times and heat-treatment temperatures) and reducing agents (DTT, b-mercaptoethanol and TCEP) were applied to purify MT isolated from fish (Oreochromis niloticus) bile and liver. Spectrophotometrical analyses were used to quantify the resulting MT samples, and SDS-PAGE gels were used to qualitatively assess the different procedure results. Each procedure was then statistically evaluated. A response surface methodology was applied for bile samples, in order to further evaluate the responses for this matrix. In an environmental context, biliary MT was lower than liver MT, and, bile MT seems to be more adequate in environmental monitoring scopes regarding recent exposure to xenobiotics that may affect the proteomic and metalloproteomic expression of this biological matrix. A procedure for exposure to metals in the laboratory showed that some metals are significantly important for the assessment of contamination from the quantification of MT, according to the data processing by atifical neural network (ANN).PAU-BU Sciences (644452103) / SudocSudocFranceF

Determination of Tl-(I) and Tl-(III) by IC-ICP-MS and application to Tl speciation analysis in the Tl hyperaccumulator plant Iberis intermedia

Copyright © 2004 Royal Society of ChemistrySpeciation of thallium was investigated in a Tl hyperaccumulator plant, Iberis intermedia, by ion chromatography (IC) and size-exclusion chromatography (SEC) coupled with on-line ICP-MS detection. The leaves, stems and roots of the plant were extracted with a buffer solution (pH 6.2) containing DTPA and ammonium acetate. DTPA was used to complex unstable Tl(III) to form the stable Tl(III)–DTPA anionic complex. The two species, Tl(I) and Tl(III)–DTPA, were separated by using two separation mechanisms, anion exchange chromatography and SEC, with 100 mmol L–1 ammonium acetate (pH 6.2) as eluant. The anion exchange chromatograms indicated that the chemical form of Tl present in extracts of both fresh and freeze-dried samples of the roots, stems and leaves is predominantly Tl(I), and this was confirmed by size-exclusion chromatography and electrospray mass spectromety.Annette Nolan, Dirk Schaumlöffel, Enzo Lombi, Laurent Ouerdane, Ryszard Lobinski and Mike McLaughli

Why is NanoSIMS elemental imaging of arsenic in seaweed ( Laminaria digitata ) important for understanding of arsenic biochemistry in addition to speciation information?

International audienceBrown seaweed such as Laminaria digitata is known to accumulate arsenic at a concentration of more than 100 mg kg−1. How the algae can tolerate such a high level of arsenic has traditionally been studied by arsenic speciation analysis using HPLC-ICPMS, but the knowledge of its molecular forms has not yet given any answers. Here we demonstrate for the first time that the combination of speciation analysis with high resolution imaging by NanoSIMS and TEM identifies not only the molecular structures of arsenic but also the location of arsenic in cells and cell substructures in a brown seaweed species. The majority of 117 mg kg−1 arsenic in L. digitata fronds was in the form of inorganic arsenic (53%) and arsenosugars (32%) and only 1.5% of total arsenic as arsenolipids (mainly as AsHC and AsPL). A lateral resolution of 300 nm and the concentration of arsenic were high enough for the localization of arsenic in the cells of the seaweed using NanoSIMS. The majority of arsenic was found in the cell walls and cell membrane, while the inside of the cell was almost arsenic free, which is not expected if the majority of arsenic species are hydrophilic. The NanoSIMS images question the integrity of the arsenic species during extraction for the speciation analysis and indicate that inorganic arsenic is unlikely to occur freely in the seaweed. Whether inorganic arsenic and the arsenosugars are bound directly to the polymeric carbohydrate alginates or fucoidans in the seaweed is unclear and needs further investigation

Diffusive Milli-Gels (DMG) for in situ assessment of metal bioavailability: A comparison with labile metal measurement using Chelex columns and acute toxicity to Ceriodaphnia dubia for copper in freshwaters

International audienceFluctuations in concentrations of bioavailable metals occur in most natural waters. In situ measurements are desirable to predict risks of adverse effects to aquatic organisms. We evaluated Diffusive Milli-Gels (DMG), a new in situ passive sampler, for assessing the bioavailability and toxicity of copper in waters exhibiting a wide range of characteristics. The performance was compared to an established Chelex-column method that measures labile copper concentrations by discrete sampling, and the ability to predict acute toxicity to the cladoceran, Ceriodaphnia dubia. The labile copper concentrations measured by the DMG and Chelex-column methods decreased with increasing dissolved organic carbon (DOC) (1.9–15 mg L−1) and hardness (21–270 mg CaCO3 L−1 hardness), with 20–70% of total dissolved copper being present as labile copper. Toxicity decreased with increasing DOC and hardness. Strong linear relationships existed between the EC50 for C. dubia and DOC, and when the EC50 was related to either the labile copper concentrations measured by DMG (r2 = 0.874) or the Chelex column (0.956) methods. The study demonstrates that the DMG passive sampler is a relevant tool for the in situ assessment of environmental risks posed by metals whose toxicity is strongly influenced by speciation. © 2016 Elsevier Lt

Speciation of nickel in a hyperaccumulating plant by high-performance liquid chromatography-inductively coupled plasma mass spectrometry and electrospray MS/MS assisted by cloning using yeast complementation

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