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Microanalysis
Kinds of Microanalysis Selected AbstractsIn-situ TiC precipitation in molten Fe-C and their characterisationCRYSTAL RESEARCH AND TECHNOLOGY, Issue 6 2008K. I. Parashivamurthy Abstract TiC particles were formed in liquid iron solution by the reaction between pure titanium and carbon available in molten iron. TiC particles have been precipitated in steels with four different carbon contents by in situ reactions during melting. The influence of titanium and carbon concentration on the precipitation of TiC was studied. The samples were studied by means of optical microscopy, scanning electron microscopy and X-ray microanalysis. The morphology of the obtained crystals was studied and correlated with carbon and titanium. It was found that TiC crystallises as primary crystals at 1600°C during solidification of the Fe-Ti-C melt. The obtained crystals were of cubic, rectangle and had maximum size of 18.7 µm. The size and shape of the carbides increases with increasing carbon and titanium in molten iron. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Electrophoretically mediated microanalysis for the evaluation of interspecies variation in cholinesterase metabolismELECTROPHORESIS, Issue 14 2010Joana Moura Abstract This study describes an electrophoretically mediated microanalysis method, suitable for the preclinical evaluation of the hydrolysis of ester drugs by the serum of different animals and for further characterization of human,animal correlation. Dog, cat, cow, horse, sheep, rat and human serum were diluted (25%) in the appropriate buffer and replaced the enzyme solution usually used in electrophoretically mediated microanalysis methods for the study of enzyme kinetics. They were then compared in terms of the ability to hydrolyze acetylthiocholine and butyrylthiocholine (0.25,mM) by in-capillary reaction. Human serum afforded the highest conversion rates (52% butyryltiocholine and 34% acetylthiocholine) followed by horse (31 and 35%), dog (26 and 24%), cat (22 and 14%), rat (11 and 15%) and sheep (8 and 8%). Hydrolysis by bovine serum was negligible. The method is fast (under 8,min including rinsing steps), sensitive (under 25,,M substrate could be quantified) and repeatable (RSD,2%), only requiring minute amounts of sample. [source] Recent developments and applications of EMMA in enzymatic and derivatization reactionsELECTROPHORESIS, Issue 1 2010Jie Zhang Abstract This review covers the time period of 2007 until mid-2009 and describes new developments in the field of electrophoretically mediated microanalysis. The review is subdivided in two parts dealing with (i) enzymatic and (ii) derivatization or chemical reactions. A compilation of the relevant literature is given for each part. [source] Development of off-line and on-line capillary electrophoresis methods for the screening and characterization of adenosine kinase inhibitors and substratesELECTROPHORESIS, Issue 12 2006Jamshed Iqbal Abstract Fast and convenient CE assays were developed for the screening of adenosine kinase,(AK) inhibitors and substrates. In the first method, the enzymatic reaction was performed in a test tube and the samples were subsequently injected into the capillary by pressure and detected by their UV absorbance at 260,nm. An MEKC method using borate buffer (pH,9.5) containing 100,mM SDS (method,A) was suitable for separating alternative substrates (nucleosides). For the CE determination of AMP formed as a product of the AK reaction, a phosphate buffer (pH,7.5 or 8.5) was used and a constant current (95,,A) was applied (method,B). The methods employing a fused-silica capillary and normal polarity mode provided good resolution of substrates and products of the enzymatic reaction and a short analysis time of less than 10,min. To further optimize and miniaturize the AK assays, the enzymatic reaction was performed directly in the capillary, prior to separation and quantitation of the product employing electrophoretically mediated microanalysis (EMMA, method,C). After hydrodynamic injection of a plug of reaction buffer (20,mM Tris-HCl, 0.2,mM MgCl2, pH,7.4), followed by a plug containing the enzyme, and subsequent injection of a plug of reaction buffer containing 1,mM,ATP, 100,,M adenosine, and 20,,M,UMP as an internal standard,(I.S.), as well as various concentrations of an inhibitor, the reaction was initiated by the application of 5,kV separation voltage (negative polarity) for 0.20,min to let the plugs interpenetrate. The voltage was turned off for 5,min (zero-potential amplification) and again turned on at a constant current of ,60,,A to elute the products within 7,min. The method employing a polyacrylamide-coated capillary of 20,cm effective length and reverse polarity mode provided good resolution of substrates and products. Dose,response curves and calculated Ki values for standard antagonists obtained by CE were in excellent agreement with data obtained by the standard radioactive assay. [source] Dual injection capillary electrophoresis: Foundations and applicationsELECTROPHORESIS, Issue 23-24 2004Feliciano Priego-Capote Abstract The state of the art of capillary electrophoresis (CE) approaches based on dual injection is here reported. Dual injection strategies have been proposed with three main objectives: (i) to provide information about reaction kinetics and/or related parameters, (ii) to perform in-capillary derivatization for improving separation and/or determination, (iii) to develop electrophoretic methods for the simultaneous analysis of anionic and cationic compounds. For the first two purposes, dual injection, which involves sample and reagent, can be realized either from the same end of the capillary (electrophoretically mediated microanalysis, EMMA) or from the two ends of the capillary (electroinjection analysis, EIA). The third objective, with dual injection of sample from the two ends of the capillary, takes advantage of moving cationic and anionic compounds with opposite directions. The foundations of each alternative, conditions necessary for working with them, restrictions, applications as well as perspectives are reviewed in order to establish the advantages, shortcomings, and convenience or no of their use in comparison to conventional CE. [source] Electrophoretically mediated microanalysis with partial filling technique and indirect or direct detection as a tool for inhibition studies of enzymatic reactionELECTROPHORESIS, Issue 7-8 2004Magdaléna Telnarová Abstract The inhibition of the model enzyme, haloalkane dehalogenase from Sphingomonas paucimobilis, was investigated by a combination of electrophoretically mediated microanalysis with a partial filling technique, followed by indirect or direct detection. In this setup, part of the capillary is filled with a buffer suitable for the enzymatic reaction (20 mM glycine buffer, pH 8.6) whereas the rest of the capillary is filled with the background electrolyte optimal for separation of substrates and products. Two different background electrolytes and corresponding detection approaches were used to show the versatility of the developed method. The inhibition effect of 1,2-dichloroethane on the dehalogenation of brominated substrate 1-bromobutane was studied by means of 10 mM chromate , 0.1 mM cetyltrimethylammonium bromide (pH 9.2) in combination with indirect detection or 20 mM ,-alanine , hydrochloric acid (pH 3.5) in combination with direct detection. The method was used to estimate the inhibition constant KI (0.44 mM by indirect detection and 0.63 mM by of direct detection) and to determine the inhibition type. Compared to spectrophotometric and other discontinuous assays, the method is rapid, can be automated, and requires only small amount of reagents that is especially important in the case of enzymes and inhibitors. [source] Electrophoretically mediated reaction of glycosidases at a nanoliter scaleELECTROPHORESIS, Issue 6 2003Yoshimi Kanie Abstract We have investigated electrophoretically mediated microanalysis (EMMA) for the assay of a native glyco-enzyme. As a representative of this class of enzyme, ,-glucosidase was selected, and the reaction was analyzed. Our EMMA was based on the plug-plug interaction of enzyme and substrate plugs, which is essential to reduce quantities of materials. Furthermore, we have addressed the problem of incompatibility of the enzymatic reaction and separation of the reactants. As a result, EMMA of native glycosidase was achieved with a reaction volume of ,,20 nL and the Michaelis constant was estimated according to the Lineweaver-Burk plot. The current method may have advantages over traditional assay methods, especially in terms of the amount of enzyme (ng order) and substrate (pmol order) required for a reaction*. [source] Grazing protozoa and magnetosome dissolution in magnetotactic bacteriaENVIRONMENTAL MICROBIOLOGY, Issue 11 2007Juliana L. Martins Summary Magnetotactic bacteria show an ability to navigate along magnetic field lines because of magnetic particles called magnetosomes. All magnetotactic bacteria are unicellular except for the multicellular prokaryote (recently named ,Candidatus Magnetoglobus multicellularis'), which is formed by an orderly assemblage of 17,40 prokaryotic cells that swim as a unit. A ciliate was used in grazing experiments with the M. multicellularis to study the fate of the magnetosomes after ingestion by the protozoa. Ciliates ingested M. multicellularis, which were located in acid vacuoles as demonstrated by confocal laser scanning microscopy. Transmission electron microscopy and X-ray microanalysis of thin-sectioned ciliates showed the presence of M. multicellularis and magnetosomes inside vacuoles in different degrees of degradation. The magnetosomes are dissolved within the acidic vacuoles of the ciliate. Depending on the rate of M. multicellularis consumption by the ciliates the iron from the magnetosomes may be recycled to the environment in a more soluble form. [source] Synthesis and Properties of Organometallic PtII and PtIV Complexes with Acyclic Selenoether and Telluroether Ligands and Selenoether MacrocyclesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 21 2006William Levason Abstract The first series of planar dimethyl(selenoether)PtII complexes, [PtMe2L] [L = MeSe(CH2)nSeMe (n = 2 or 3), o -C6H4(CH2SeMe)2, [8]aneSe2 (1,5-diselenacyclooctane), or [16]aneSe4 (1,5,9,13-tetraselenacyclohexadecane)], have been obtained by treatment of [PtMe2(SMe2)2] with L in Et2O solution and characterised by VT 1H, 13C{1H}, 77Se{1H} and 195Pt{1H} NMR spectroscopy, electrospray MS and microanalysis. The corresponding dimethyl(telluroether)PtII complexes do not form under similar reaction conditions. The distorted octahedral [PtMe3I(L)] [L = o -C6H4(CH2SeMe)2, [8]aneSe2, [16]aneSe4 or MeC(CH2SeMe)3] form as stable complexes in good yield from reaction of PtMe3I with L in refluxing CHCl3 and have been characterised similarly. These all show bidentate selenoether coordination, with fast pyramidal inversion occurring at room temperature. The distorted octahedral coordination environment at PtIV is also confirmed from a crystal structure of [PtMe3I{o -C6H4(CH2SeMe)2}]. Rare examples of (telluroether)PtIV complexes, [PtMe3I{o -C6H4(CH2TeMe)2}] and the dinuclear [Me3Pt(,2 -I)2(,2 -MeTeCH2TeMe)PtMe3], have also been prepared and characterised similarly (and also by 125Te{1H} NMR spectroscopy). The [8]aneSe2 and [16]aneSe4 species are the first examples of alkyl PtII or PtIV complexes with (macro)cyclic selenoether coordination. Halide abstraction (TlPF6) from [PtMe3I(,2 -[16]aneSe4)] affords [PtMe3(,3 -[16]aneSe4)]PF6; a rare example of a cationic PtIV selenoether. The (diselenoether)PtII complexes undergo oxidative addition of MeI to yield the corresponding PtIV species [PtMe3I(diselenoether)]. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Syntheses and Coordination Chemistry of Aminomethylphosphine Derivatives of AdenineEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 13 2003Qingzhi Zhang Abstract Two aminomethylphosphane derivatives of adenine 9-(2-{bis[(diphenylphosphanyl)methyl]amino}ethyl)adenine (La) and 9-(3-{bis[(diphenylphosphanyl)methyl]amino}propyl)adenine (Lb) were synthesised. Oxidation of La and Lb with H2O2, elemental sulfur or elemental selenium led to the corresponding oxidized products 4a/b,6a/b. Both La and Lb behave as didentate ligands towards late transition metals. Reaction of La or Lb with [MX2(cod)] (M = Pd, Pt; X = Cl, Me) gave chelate complexes 7a/b,10a/b. Reaction of La or Lb with [AuCl(tht)] or [{RuCl(,-Cl)(p -MeC6H4iPr)}2] gave the didentate bridging complexes 11a/b and 12a. All compounds have been fully characterised by microanalysis, IR, 1H and 31P{1H} NMR spectroscopy, and EI/CI/FAB mass spectrometry. 1H{31P} NMR and 1H- 13C correlation experiments were used to confirm the spectral assignments where necessary. Two compounds were structurally characterised by X-ray crystallographic analysis. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] High-Pressure Torsion for Giant Magnetoresistance and Better Magnetic Properties,ADVANCED ENGINEERING MATERIALS, Issue 8 2010Shingo Nishihata High-pressure torsion (HPT) was conducted on Cu alloys containing ferromagnetic Co and Fe particles. Electron probe microanalysis, X-ray diffraction analysis, and transmission electron microscopy confirmed that the particles were significantly refined through fragmentation and some fractions were dissolved into the Cu matrix with straining by HPT. Saturation magnetization decreases with straining and coercive force increases with straining but they level off after intense straining. Magnetoresistance with an isotropic feature corresponding to giant magnetoresistance (GMR) appears at room temperature by processing with HPT. It is demonstrated that HPT is a potential process for controlling magnetic properties such as saturation magnetization and coercive force and also for creating GMR in the alloys prepared by conventional ingot metallurgy. [source] Analysis of the behaviour of the structural concrete after the fire at the Windsor Building in MadridFIRE AND MATERIALS, Issue 2 2010E. Menéndez Abstract The analysis of the concrete subjected to high temperatures is usually undertaken by means of tests specifically designed and carried out in the laboratory, or by using theoretical approaches using standardized curves for theoretical fires. An analysis by different techniques has been carried out on structural concrete to real fire of Windsor Building in Madrid, which was severally damaged by a fire in 2005. These techniques are X-ray diffraction, differential thermal and thermogravimetric analysis and backscattered electron microscopy with dispersive X-ray microanalysis. Samples of the concrete were taken from different floors in the building and analyses were carried out at different depths starting from the surface exposed to the fire itself. The analysis allows the damaged area to be limited as well as situating the 500,C isotherm in the concrete element. In accordance with the results obtained, the damage is limited to just a few centimeters from the surface exposed to the fire itself, in spite of its prolonged exposure to the fire. This would justify that the concrete has demonstrated a suitable resistant behaviour. Likewise, it can be deduced from the results obtained that the fire, to which the concrete was subjected, can be qualified as severe. Also, these results can confirm that the calculation hypothesis in the project is correct in relation to the fire resistance exigencies of the concrete. Copyright © 2009 John Wiley & Sons, Ltd. [source] Enhanced Optical Properties and Opaline Self-Assembly of PPV Encapsulated in Mesoporous Silica SpheresADVANCED FUNCTIONAL MATERIALS, Issue 23 2009Timothy L. Kelly Abstract A new poly(p -phenylenevinylene) (PPV) composite material has been developed by the incorporation of insoluble PPV polymer chains in the pores of monodisperse mesoporous silica spheres through an ion-exchange and in situ polymerization method. The polymer distribution within the resultant colloidal particles is characterized by electron microscopy, energy dispersive X-ray microanalysis, powder X-ray diffraction, and nitrogen adsorption. It was found that the polymer was selectively incorporated into the mesopores of the silica host and was well distributed throughout the body of the particles. This confinement of the polymer influences the optical properties of the composite; these were examined by UV,vis and fluorescence spectroscopy and time-correlated single-photon counting. The results show a material that exhibits an extremely high fluorescence quantum yield (approaching 85%), and an improved resistance to oxidative photobleaching compared to PPV. These enhanced optical properties are further complemented by the overall processability of the colloidal material. In marked contrast to the insolubility of PPV, the material can be processed as a stable colloidal dispersion, and the individual composite spheres can be self-assembled into opaline films using the vertical deposition method. The bandgap of the opal can be engineered to overlap with the emission band of the polymer, which has significant ramifications for lasing. [source] WDX Studies on Ceramic Diffusion Barrier Layers of Metal Supported SOECsFUEL CELLS, Issue 6 2009D. Wiedenmann Abstract Solid oxide electrolyser cells (SOECs) have great potential for efficient and economical production of hydrogen fuel. Element diffusion between the Ni-cermet electrode and the metal substrate of metal supported cells (MSC) is a known problem in fuel cell and electrolysis technology. In order to hinder this unintentional mass transport, different ceramic diffusion barrier layers (DBLs) are included in recent cell design concepts. This paper is based on wavelength dispersive X-ray fluorescence investigations of different SOEC and focuses on Fe, Cr and Ni diffusion between the metal grains of the cathode and the metal substrate. Due to the low detection limits and therefore high analytical sensitivity, wavelength dispersive electron probe microanalysis (EPMA) provides a precise method to determine element distribution, absolute element concentration and changes between the reference material and aged cells on a microstructural level by element mappings and concentration profiles. The results of this work show considerable concentration gradients in the metal grains caused by mass exchange during cell operation. Diffusion can be inhibited significantly by integrating different ceramic DBLs of doped LaCrO3 -type or doped LaMnO3 -type perovskite, either by vacuum plasma spraying (VPS) or physical vapour deposition technique (PVD). [source] Mouse inbred strain differences in ethanol drinking to intoxicationGENES, BRAIN AND BEHAVIOR, Issue 1 2007J. S. Rhodes Recently, we described a simple procedure, Drinking in the Dark (DID), in which C57BL/6J mice self-administer ethanol to a blood ethanol concentration (BEC) above 1 mg/ml. The test consists of replacing the water with 20% ethanol in the home cage for 4 h early during the dark phase of the light/dark cycle. Three experiments were conducted to explore this high ethanol drinking model further. In experiment 1, a microanalysis of C57BL/6J behavior showed that the pattern of ethanol drinking was different from routine water intake. In experiment 2, drinking impaired performance of C57BL/6J on the accelerating rotarod and balance beam. In experiment 3, 12 inbred strains were screened to estimate genetic influences on DID and correlations with other traits. Large, reliable differences in intake and BEC were detected among the strains, with C57BL/6J showing the highest values. Strain means were positively correlated with intake and BEC in the standard (24 h) and a limited (4 h) two-bottle ethanol vs. water test, but BECs reached higher levels for DID. Strain mean correlations with other traits in the Mouse Phenome Project database supported previously reported genetic relationships of high ethanol drinking with low chronic ethanol withdrawal severity and low ethanol-conditioned taste aversion. We extend these findings by showing that the correlation estimates remain relatively unchanged even after correcting for phylogenetic relatedness among the strains, thus relaxing the assumption that the strain means are statistically independent. We discuss applications of the model for finding genes that predispose pharmacologically significant drinking in mice. [source] Monte Carlo Study of Quantitative Electron Probe Microanalysis of Monazite with a Coating Film: Comparison of 25 nm Carbon and 10 nm Gold at E0= 15 and 25 keVGEOSTANDARDS & GEOANALYTICAL RESEARCH, Issue 2 2007Takenori Kato simulation par la méthode de Monte Carlo; microanalyse par sonde électronique (EPMA); analyse quantitative; film de revêtement; monazite Carbon (25,30 nm in thickness) is the most common coating material used in the electron probe microanalysis (EPMA) of geological samples. A gold coating is also used in special cases to reduce the surface damage by electron bombardment. Monte Carlo simulations have been performed for monazite with a 25 nm carbon and a 10 nm gold coating to understand the effect of a coating film in quantitative EPMA at E0= 15 keV and 25 keV. Simulations showed that carbon-coated monazite gave the same depth distribution of the generated X-rays in the monazite as uncoated monazite, whilst gold-coated monazite gave a distorted depth distribution. A 10 nm gold coating was 1.06 (15 keV) and 1.05 (25 keV) times higher in k -ratio between monazite and pure thorium than a 25 nm carbon coating at an X-ray take-off angle of 40 degrees. Thus, a 10 nm gold coating is a possible factor contributing to inaccuracy in quantitative EPMA of monazite, while a 25 nm carbon coating does not have a significant effect. Le carbone, avec des épaisseurs de 25 à 30 nm, est le matériel de dépôt le plus fréquemment utilisé en microanalyse par sonde électronique (EPMA) d'échantillons géologiques. Un dépôt d'or est aussi utilisé dans des cas spécifiques, pour réduire les dommages causés à la surface par le bombardement d'électrons. Des simulations par la méthode de Monte Carlo ont été effectuées pour une monazite recouverte d'une couche de carbone de 25 nm et d'une couche d'or de 10 nm, dans le but de comprendre l'effet du dépôt dans les mesures quantitatives à l'EPMA, à E0= 15 keV et 25 keV. Les simulations ont montré que la monazite recouverte de carbone avait la même distribution en profondeur de rayons X générés qu'une monazite non recouverte, tandis que la monazite recouverte d'or avait une distribution en profondeur déformée. Le dépôt de 10 nm d'or avait un k -ratio qui était 1.06 (pour 15 keV) et 1.05 (pour 25 keV) fois plus important pour la monazite et du thorium pur que le dépôt de 25 nm de carbone dans le cas d'un angle de sortie des rayons X de 40 degrés. En conséquence un dépôt d'or de 10 nm est un facteur possible d'inexactitude lors de mesures quantitatives de monazites par EPMA, alors qu'un dépôt de carbone de 25 nm n'a pas d'effet significatif sur la mesure. [source] Application of High Spatial Resolution Laser Ablation ICP-MS to Crystal-Melt Trace Element Partition Coefficient DeterminationGEOSTANDARDS & GEOANALYTICAL RESEARCH, Issue 1 2007Maurizio Petrelli ICP-MS; ablation laser; éléments en trace; figure de mérite; coefficients de partage entre cristal et liquide In this contribution we evaluate the capabilities of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) using a 12 ,m spot size. Precision, accuracy and detection limits were assessed on the USGS BCR-2G reference material. We demonstrate that the 12 ,m LA-ICP-MS analyses of experimentally-grown amphibole and garnet are in excellent agreement with secondary ion mass spectrometry (SIMS) trace element determinations on the same crystals. The 12 ,m spot size configuration was subsequently used to determine trace element crystal-melt partition coefficients (Dc/m) for a wide range of trace elements in amphibole in equilibrium with a basanitic melt. The following strategy to determine accurately and evaluate Dc/m is proposed. One or more major elements determined previously by electron probe microanalysis (EPMA) was used to ensure consistency between EPMA and the composition of the aerosol produced by the laser ablation. Measured Dc/m values were successively evaluated using the lattice strain model. The use of this strategy significantly improved the precision and accuracy of Dc/m determination when a LA-ICP-MS configuration with a high spatial resolution was employed. Dans cet article nous évaluons les potentialités de l'ablation laser couplée à un spectromètre de masse à plasma induit (LA-ICP-MS) en travaillant avec un diamètre d'impact de 12 ,m. Précision, justesse et limites de détections sont évaluées sur le matériau de référence BCR-2G de l'USGS. Nous démontrons que les analyses LA-ICP-MS faites avec un diamètre de 12 ,m sur les amphiboles et des grenats synthétiques sont en excellent accord avec les déterminations d'éléments en trace effectuées sur les mêmes cristaux par sonde ionique (SIMS). Ce diamètre d'impact de 12 ,m a donc été sélectionné pour déterminer les coefficients de partage cristal/liquide (Dc/m) pour un grand nombre d'éléments en trace dans une amphibole en équilibre avec un liquide basanitique. Nous proposons la stratégie d'analyse suivante, qui assure une détermination exacte des coefficients de partage Dc/m. Un ou plusieurs des éléments majeurs déterminés auparavant par microsonde électronique (EMPA) est utilisé pour garantir la consistance des données entre EMPA et la composition de l'aérosol produit par l'ablation laser. Les Dc/m mesurés sont ensuite évalués en utilisant le modèle de contrainte de réseau. L'utilisation de cette stratégie améliore de manière significative la précision et la justesse des déterminations de Dc/m quand elle est couplée à l'utilisation d'un système LA-ICP-MS de grande résolution spatiale. [source] Reference Materials in Geoanalytical Research -Review for 2004 and 2005GEOSTANDARDS & GEOANALYTICAL RESEARCH, Issue 3 2006Klaus Peter Jochum This review gives an overview of the use and development of reference materials of geochemical and environmental interest in the literature of the years 2004 and 2005. In these years the performance of existing methods has been improved and new geochemical applications using new techniques have been developed. Accordingly, there was an increasing need for new reference materials, especially for in situ microanalysis and for precise stable isotope measurements. In addition, there was a notable trend for further characterisation of existing reference materials, mainly for the platinum-group elements. This review focuses on five topics: reference materials for platinum-group elements, reference glasses for in situ microanalysis, zircon reference materials, isotopic reference materials, and the development and certification of reference materials. [source] Preparation of a Synthetic Titanite Glass Calibration Material for In Situ Microanalysis by Direct Fusion in Graphite Electrodes: A Preliminary Characterisation by EPMA and LA-ICP-MSGEOSTANDARDS & GEOANALYTICAL RESEARCH, Issue 2 2005Magne Ødegård matériaux de calibration; microanalyse; fusion directe; électrodes de graphite; verre de titanite This paper describes a technique for the preparation of a titanite (CaTiSiO5) glass calibration material for use in in situ microanalysis of major, minor, and trace elements in geological materials. The starting composition was a titanite matrix doped with minor and trace elements at , 200 ,g g -1. The elements Sc, Y, REEs, Th and U were added in the form of nitrates in solution, and the elements V, Cr, Mn, Fe, Co, Ni, Zr, Nb, Hf and W were added as solid oxides. The synthetic titanite glass was produced by direct fusion by resistance heating in graphite electrodes at 1600-1700 °C, and quenched in air. Backscattered electron images indicate good homogeneity, with no signs of separate phases or vesicles, and analysis of the major elements Ca, Ti and Si by electron microprobe showed relative standard deviations between 0.5 and 0.7%, based on six independent measurements. Deviations from nominal concentrations for Ca, Si and Ti were measured to -1.2, -3.3 and -0.8%, respectively. The homogeneity of the trace elements in the glass was assessed by LA-ICP-MS analyses, using NIST SRM 610, 612 and 616 as external calibrators, and Ca as the internal standard element. Determinations were made both with a quadrupole mass spectrometer and a sector field instrument, and both raster and spot modes of analysis were used. For the majority of doped elements, precision was better than 10%, and relative deviations from nominal values were, with few exceptions, between 5 and 10%. Cet article décrit une technique de préparation d'un verre de composition CaTiSiO5 (titanite) pour l'utiliser comme matériau de calibration lors de microanalyses in situ des éléments majeurs, mineurs et en trace dans des matériaux géologiques. La composition de départ a une matrice de titanite, dopée avec des éléments mineurs et en trace à une concentration de , 200 ,g g-1. Les éléments Sc, Y, REE, Th et U ont été ajoutés sous forme de nitrates en solution et les éléments V, Cr, Mn, Fe, Co, Ni, Zr, Nb, Hf et W sous forme d'oxydes solides. Le verre synthétique de titanite a été produit par fusion directe avec un chauffage par des résistances dans des électrodes de graphite à 1600-1700 °C suivi d'un refroidissement rapide à l'air. Les images obtenues par électrons rétrodiffusés montrent que le verre présente une bonne homogénéité, sans aucun signe de phases individualisées ou de vésicules, et l'analyse des éléments majeurs Ca, Ti et Si par microsonde électronique a des déviations standard relatives (RSD) entre 0.5 et 0.7% provenant de six mesures indépendantes. Les déviations par rapport aux concentrations calculées, pour Ca, Si et Ti, sont de -1.2, -3.3 et -0.8% respectivement. L'homogénéité de répartition des éléments en trace dans le verre a été vérifiée par des analyses LA-ICP-MS, en utilisant les matériaux de référence NIST SRM 610, 612 et 616 pour la calibration externe et Ca comme élément standard interne. Les déterminations ont été faites avec un spectromètre de masse de type quadrupôle et un autre de type secteur magnétique, par des analyses à la fois en mode balayage et en mode ponctuel. Pour la majorité des éléments dopés, la précision est meilleure que 10% et les déviations standard relatives par rapport aux valeurs calculées sont, à quelques exceptions près, entre 5 et 10%. [source] Further Characterisation of the 91500 Zircon CrystalGEOSTANDARDS & GEOANALYTICAL RESEARCH, Issue 1 2004Michael Wiedenbeck zircon 91500; matériau de référence; intercomparaison entre techniques; valeurs de travail This paper reports the results from a second characterisation of the 91500 zircon, including data from electron probe microanalysis, laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS), secondary ion mass spectrometry (SIMS) and laser fluorination analyses. The focus of this initiative was to establish the suitability of this large single zircon crystal for calibrating in situ analyses of the rare earth elements and oxygen isotopes, as well as to provide working values for key geochemical systems. In addition to extensive testing of the chemical and structural homogeneity of this sample, the occurrence of banding in 91500 in both backscattered electron and cathodoluminescence images is described in detail. Blind intercomparison data reported by both LA-ICP-MS and SIMS laboratories indicate that only small systematic differences exist between the data sets provided by these two techniques. Furthermore, the use of NIST SRM 610 glass as the calibrant for SIMS analyses was found to introduce little or no systematic error into the results for zircon. Based on both laser fluorination and SIMS data, zircon 91500 seems to be very well suited for calibrating in situ oxygen isotopic analyses. Cet article présente les résultats d'une nouvelle caractérisation du zircon 91500, dont des données de microanalyse par sonde électronique, d'analyse par ablation laser en couplage à un ICP-MS, d'analyse par sonde ionique (SIMS) et d'analyse par fluorination laser. Le but de cette étude etait de démontrer que ce large monocristal de zircon pouvait être utilisé pour la calibration d'analyses in situ de Terres Rares et des isotopes de I'Oxygène, et en même temps de fournir des valeurs "de travail" pour un certain nombre de systémes géochimiques cruciaux. En complément des tests systématiques d'homogénéité de I'échantillon, tant chimiquement que structurellement, /'ex/sfence, dans le zircon 91500, de zonages visibles en électrons retro diffusés et en cathodoluminescence, est décrite en détail, line comparaison en aveugle des résultats obtenus par LA-ICP-MS et par SIMS, dans des laboratoires différents, montre que les différences systématiques entre les ensembles de données obtenues par ces deux techniques sont très faibles. De plus, I'utilisation du verre NIST SRM 610 comme calibrant lors de I'analyse par SIMS n'introduit qu'une erreur systématique très faible si ce n'est inexistante sur les résultats du zircon. Sur la base des analyses par fluorination laser et par SIMS, le zircon 91500 semble être parfaitement adapte a son utilisation pour la calibration d'analyses isotopiques in situ d'oxygène. [source] The complexity of individuationINTERNATIONAL JOURNAL OF APPLIED PSYCHOANALYTIC STUDIES, Issue 4 2004Inna Semetsky Honorary Research Associate Abstract This paper addresses the problematics of individuation in Deleuze and Guattari's philosophy. The concept of fold , the inside of the outside , is analyzed in terms of the relations between thought and unthought constituting the process of thinking in affects. It is suggested that thinking of this sort, called by Deleuze the supreme act of philosophy, may be considered tending towards Jungian and post-Jungian depth psychology. The unconscious of thought is described by the archetypal dynamics of forces acting in the space of the Outside, that this paper posits as the field of collective unconscious. Analogous to Deleuzian virtual tendencies, Jungian archetypes subsist in potentia only and, as a multiplicity of relations between forces, can be expressed through cartographic microanalysis. In accord with Deleuze's method of transcendental empiricism, the unconscious, immanent, microperceptions are reterritorialized by means of mapping the archetypal field. Copyright © 2004 Whurr Publishers Ltd. [source] Defective enamel ultrastructure in diabetic rodentsINTERNATIONAL JOURNAL OF PAEDIATRIC DENTISTRY, Issue 4 2004M. ATAR Summary. We investigated six different types of diabetic rodents. Four expressed a genetic obesity resulting in diabetes. One developed diabetes induced by a diet-dependent obesity, and one with genetic diabetes received anti-diabetic medication. The tooth samples were examined under a scanning electron microscope and with an energy dispersive microanalysis (EDX). The electron micrographs showed severe, varying degrees of damage within the six different diabetic animal types, such as irregular crystallite deposition and prism perforations in genetically obese animals compared to less-disordered prism structures in diet-dependent obesity. Anti-diabetic medication resulted in normal enamel ultrastructure. The EDX analysis revealed a reduction in the amount of calcium and phosphorus in all regions affected by diabetes. Based on these animal studies, we suggest that both juvenile diabetes type I (in infants) and adult diabetes type II (in pregnant mothers, affecting the developing foetus) may affect the normal development of teeth in humans. [source] Silica-Supported Zirconium Complexes and their Polyoligosilsesquioxane Analogues in the Transesterification of Acrylates: Part 1.ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 13 2009Characterization, Synthesis Abstract Various silica-supported acetylacetonate and alkoxy zirconium(IV) complexes have been prepared and characterized by quantitative chemical measurements of the surface reaction products, quantitative surface microanalysis of the surface complexes, in situ infrared spectroscopy, CP-MAS 13C,NMR spectroscopy and EXAFS. The complex (SiO)Zr(acac)3 (acac=acetylacetonate ligand) (1) can be obtained by reaction of zirconium tetraacetylacetonate [Zr(acac)4] with a silica surface previously dehydroxylated at 500,°C. The complexes (SiO)3Zr(acac) (2) and (SiO)3Zr(O- n- Bu) (n- Bu=butyl ligand) (3) can be synthesized by reaction of (SiO)3ZrH with, respectively, acetylacetone and n -butanol at room temperature. The spectroscopic data, including EXAFS spectroscopy, confirm that in compound 1 the zirconium is linked to the surface by only one SiOZr bond whereas in the case of compounds 2 and 3 the zirconium is linked to 3 surface oxygen atoms which are sigma bonded. EXAFS data indicate also that the acetylacetonate ligands behave as chelating ligands leading to a hepta-coordination around the zirconium atom in 1 and a penta-coordination in 2. In order to provide a molecular analogue of 1, the synthesis of the following polyoligosilsesquioxane derivative (c -C5H9)7Si8O12(CH3)2Zr(acac)3 (1,) was achieved. The compound 1, is obtained by reacting (c -C5H9)7Si8O11(CH3)2(OH), 4, with an equimolecular amount of Zr(acac)4. In the same manner, syntheses of complexes (c -C5H9)7Si7O12Zr(acac) (2,) and of (c-C5H9)7Si7O12Zr(O- n- Bu) (3,) were achieved by reaction of the unmodified trisilanol, (c -C5H9)7Si7O9(OH)3, with respectively Zr(acac)4 and Zr(O- n- Bu)4 at 60,°C in tetrahydrofuran. Compounds 1,, 2, and 3, can be considered as good models of 1, 2 and 3 since their spectroscopic properties are comparable with those of the surface complexes. The synthetic results obtained will permit us to study the catalytic properties of these surface complexes and of their molecular analogues with the ultimate goal of delineating clear structure-activity relationships. [source] Role of uric acid in different types of calcium oxalate renal calculiINTERNATIONAL JOURNAL OF UROLOGY, Issue 3 2006FÉLIX GRASES Aim:, The presence of uric acid in the beginning zone of different types of ,pure' calcium oxalate renal calculi was evaluated with the aim of establishing the degree of participation of uric acid crystals in the formation of such calculi. Methods:, The core or fragment of different types of ,pure' calcium oxalate renal calculi was detached, pulverized and uric acid extracted. Uric acid was determined using a high-performance liquid chromatography/mass spectrometry method. Results:, In calcium oxalate monohydrate (COM) papillary calculi with a core constituted by COM crystals and organic matter, 0.030 ± 0.007% uric acid was found in the core. In COM papillary calculi with a core constituted by hydroxyapatite, 0.031 ± 0.008% uric acid was found in the core. In COM unattached calculi (formed in renal cavities) with the core mainly formed by COM crystals and organic matter, 0.24 ± 0.09% uric acid was found in the core. In COM unattached calculi with the core formed by uric acid identifiable by scanning electron microscopy (SEM) coupled to X-ray microanalysis, 20.8 ± 7.8% uric acid was found in the core. In calcium oxalate dihydrate (COD) unattached calculi containing little amounts of organic matter, 0.012 ± 0.004% uric acid was found. In COD unattached calculi containing little amounts of organic matter and hydroxyapatite, 0.0030 ± 0.0004% of uric acid was found. Conclusions:, From these results it can be deduced that uric acid can play an important role as inducer (heterogeneous nucleant) of COM unattached calculi with the core formed by uric acid identifiable by SEM coupled to X-ray microanalysis (these calculi constitute the 1.2% of all calculi) and in COM unattached calculi with the core mainly formed by COM crystals and organic matter (these calculi constitute the 10.8% of all calculi). [source] SHRIMP zircon and EPMA monazite dating of granitic rocks from the Maizuru terrane, southwest Japan: Correlation with East Asian Paleozoic terranes and geological implicationsISLAND ARC, Issue 3 2008Masahiro Fujii Abstract The Maizuru terrane, distributed in the Inner Zone of southwest Japan, is divided into three subzones (Northern, Central and Southern), each with distinct lithological associations. In clear contrast with the Southern zone consisting of the Yakuno ophiolite, the Northern zone is subdivided into the western and eastern bodies by a high-angle fault, recognized mainly by the presence of deformed granitic rocks and pelitic gneiss. This association suggests an affinity with a mature continental block; this is supported by the mode of occurrence, and petrological and isotopic data. Newly obtained sensitive high mass-resolution ion microprobe (SHRIMP) zircon U,Pb ages reveal the intrusion ages of 424 ± 16 and 405 ± 18 Ma (Siluro,Devonian) for the granites from the western body, and 249 ± 10 and 243 ± 19 Ma (Permo,Triassic) for the granodiorites from the eastern body. The granites in the western body also show inherited zircon ages of around 580 and 765 Ma. In addition, electron probe microanalysis (EPMA) monazite U,Th,total Pb dating gives around 475,460 Ma. The age of intrusion, inherited ages, mode of occurrence, and geological setting of the Siluro,Devonian granites of the Northern zone all show similarities with those of the Khanka Massif, southern Primoye, Russia, and the Hikami granitic rocks of the South Kitakami terrane, Northeast Japan. We propose that both the Siluro,Devonian and Permo,Triassic granitic rocks of the Northern zone are likely to have been juxtaposed through the Triassic,Late Jurassic dextral strike-slip movement, and to have originated from the Khanka Massif and the Hida terrane, respectively. This study strongly supports the importance of the strike-slip movement as a mechanism causing the structural rearrangement of the Paleozoic,Mesozoic terranes in the Japanese Islands, as well as in East Asia. [source] Environmental signature in the otolith elemental fingerprint of the tapertail anchovy, Coilia mystus, from the Changjiang estuary, ChinaJOURNAL OF APPLIED ICHTHYOLOGY, Issue 5 2006J. Yang Summary The ontogenetic patterns of habitat use and the migratory history of the tapertail anchovy, Coilia mystus, collected in the Changjiang estuary around Chongming Island, China, were studied by examining the environmental signature in the otolith strontium (Sr) and calcium (Ca) fingerprints using electron probe microanalysis (EPMA). Our results suggest that the migration strategy of C. mystus is much more flexible than supposed in the literature to date. The spring spawning population of C. mystus from the studied area was found to consist of individuals with different migration histories. Although the tapertail anchovy seems to be an anadromous fish that spawns and hatches in a freshwater habitat, it can also use a freshwater environment in non-spawning seasons. The otolith EPMA of the elemental fingerprint (Sr x-ray maps and Sr : Ca ratios) is an environmental indicator that can be applied to the migratory ecology of other important diadromous species in China. [source] Mitochondrial DNA mutations as a fundamental mechanism in physiological declines associated with agingAGING CELL, Issue 1 2003Jeong W. Pak Summary The hypothesis that mitochondrial DNA damage accumulates and contributes to aging was proposed decades ago. Only recently have technological advancements, which facilitate microanalysis of single cells or portions of cells, revealed that mtDNA deletion mutations and, perhaps, single nucleotide mutations accumulate to physiologically relevant levels in the tissues of various species with age. Although a link between single nucleotide mutations and physiological consequences in aging tissue has not been established, the accumulation of deletion mutations in skeletal muscle fibres has been associated with sarcopenia. Different, and apparently random, deletion mutations are specific to individual fibres. However, the mtDNA deletion mutation within a phenotypically abnormal region of a fibre is the same, suggesting a selection, amplification and clonal expansion of the initial deletion mutation. mtDNA deletion mutations within a muscle fibre are associated with specific electron transport system abnormalities, muscle fibre atrophy and fibre breakage. These data point to a causal relationship between mitochondrial DNA mutations and the age-related loss of muscle mass. [source] Differentiation of sulfate and phosphate by H/D exchange mass spectrometry: application to isoflavoneJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 11 2004Akira Kanakubo Abstract Often phosphorylation or sulfation is an important step which occurs in the signal transduction and cascade of metabolic pathways. Some natural products and metabolites contain one or more sulfate or phosphate groups. Isoflavone sulfate has been identified from high-resolution mass spectrometry (HRMS) and enzymatic digestion by sulfatase. We previously reported the new water-soluble isoflavone analogs, daidzein 7- O -phosphate and genistein 7- O -phosphate, which were surprisingly hydrolyzed by sulfatase. In this previous study, we could not determine the phosphate from the results of HRMS and enzymatic digestion, that is, HRMS and enzymatic digestion did not provide clear evidence. In this case, we drew conclusions from NMR analysis. HRMS has been ineffective with a regular fast atom bombardment (FAB) mass spectrometer to distinguish between phosphate and sulfate since the mass difference is only 0.009 mass units. There was, however, no conventional method of microanalysis to distinguish phosphate from sulfate owing to the same nominal mass. It is still very difficult to determine by negative FABMS [OP(O)(OH)2] = 80 and [OS(O)2OH] = 80. In this paper, we report a method to distinguish between these groups by using a popular low-resolution mass instrument; thus, phosphate and sulfate were measured by H/D exchange mass spectrometry at the picomole level to differentiate [OP(O)(OD)2] = 82 and [OS(O)2OD] = 81, respectively. This method is applicable not only to the isoflavone, but also to other phospho and sulfo compounds. Copyright © 2004 John Wiley & Sons, Ltd. [source] Application of the parametric bootstrap method to determine statistical errors in quantitative X-ray microanalysis of thin filmsJOURNAL OF MICROSCOPY, Issue 1 2007ALDO ARMIGLIATO Summary We applied the parametric bootstrap to the X-ray microanalysis of Si-Ge binary alloys, in order to assess the dependence of the Ge concentrations and the local film thickness, obtained by using previously described Monte Carlo methods, on the precision of the measured intensities. We show how it is possible by this method to determine the statistical errors associated with the quantitative analysis performed in sample regions of different composition and thickness, but by conducting only one measurement. We recommend the use of the bootstrap for a broad range of applications for quantitative microanalysis to estimate the precision of the final results and to compare the performances of different methods to each other. Finally, we exploited a test based on bootstrap confidence intervals to ascertain if, for given X-ray intensities, different values of the estimated composition in two points of the sample are indicative of an actual lack of homogeneity. [source] An ultrastructural study of cellular response to variation in porosity in phase-pure hydroxyapatiteJOURNAL OF MICROSCOPY, Issue 2 2004B. ANNAZ Summary Hydroxyapatite has been shown to be biocompatible and bioactive. Incorporation of porosity has been shown to enhance osteointegration; however, difficulty in controlling the extent and type of porosity has limited investigation into determining the role of both macro- and microporosity. The current investigation reports on the synthesis of four types of phase-pure hydroxyapatite with varying levels of porosity (HA1,HA4), and with defined levels of macro- and microporosities. Transmission electron microscopy was used to evaluate qualitatively the effect of these two parameters on cell,material interactions following a 30-day incubation period. Biological mineralization was observed within vesicles and the needle-like minerals were confirmed as hydroxyapatite using X-ray microanalysis. This demonstrated the suitability of primary human osteoblast-like cells as a tool to assess the extent of mineralization. Furthermore, internalization of hydroxyapatite particles was observed. Our findings show that the variation in macro- and microporosity does not affect the extent of cell,material interaction, with collagen synthesis evident in all samples. [source] | |||||||||||||||||||||||||||||||