Garnet growth in the metasediments of the Zermatt-Saas Fee zone (western alps)

The Zermatt-Saas Fee Zone (ZSZ) in the Western Alps consists of multiple slices of ultramafic, mafic and metasedimentary rocks. They represent the remnants of the Mesozoic Piemonte-Ligurian oceanic basin which was subducted to eclogite facies conditions with peak pressures and temperatures of up to 20-28 kbar and 550-630 °C, followed by a greenschist overprint during exhumation. Previous studies, emphasizing on isotopie geochronology and modeling of REE-behavior in garnets from mafic eclogites, suggest that the ZSZ is buildup of tectonic slices which underwent a protracted diachronous subduction followed by a rapid synchronous exhumation. In this study Rb/Sr geochronology is applied to phengite included in garnets from metasediments of two different slices of the ZSZ to date garnet growth. Inclusion ages for 2 metapelitic samples from the same locality from the first slice are 44.25 ± 0.48 Ma and 43.19 ± 0.32 Ma. Those are about 4 Ma older than the corresponding matrix mica ages of respectively 40.02 ± 0.13 Ma and 39.55 ± 0.25 Ma. The inclusion age for a third calcschist sample, collected from a second slice, is 40.58 ± 0.24 Ma and the matrix age is 39.8 ± 1.5 Ma. The results show that garnet effectively functioned as a shield, preventing a reset of the Rb/Sr isotopie clock in the included phengites to temperatures well above the closure of Sr in mica. The results are consistent with the results of former studies on the ZSZ using both Lu/Hf and Sm/Nd geochronology on mafic eclogites. They confirm that at least parts of the ZSZ underwent close to peak metamorphic HP conditions younger than 43 m.y. ago before being rapidly exhumed about 40 m.y. ago. Fluid infiltration in rocks of the second slice occurred likely close to the peak metamorphic conditions, resulting in rapid growth of garnets. Similar calcschists from the same slice contain two distinct types of porphyroblast garnets with indications of multiple growth pulses and resorption indicated by truncated chemical zoning patterns. In-situ oxygen isotope Sensitive High Resolution Ion Microprobe (SHRIMP) analyses along profiles on central sections of the garnets reveal variations of up to 5 %o in individual garnets. The complex compositional zoning and graphite inclusion patterns as well as the variations in oxygen isotopes correspond to growing under changing fluid composition conditions caused by external infiltrated fluids. The ultramafic and mafic rocks, which were subducted along with the sediments and form the volumetrically most important part of the ZSZ, are the likely source of those mainly aqueous fluids. - La Zone de Zermatt-Saas Fee (ZZS) est constituée de multiples écailles de roches ultramafiques, mafiques et méta-sédimentaires. Cette zone, qui affleure dans les Alpes occidentales, représente les restes du basin océanique Piémontais-Ligurien d'âge mésozoïque. Lors de la subduction de ce basin océanique à l'Eocène, les différentes roches composant le planché océanique ont atteint les conditions du faciès éclogitique avec des pressions et des températures maximales estimées entre 20 - 28 kbar et 550 - 630 °C respectivement, avant de subir une rétrogression au faciès schiste vert pendant l'exhumation. Différentes études antérieures combinant la géochronologie isotopique et la modélisation des mécanismes gouvernant l'incorporation des terres rares dans les grenats des éclogites mafiques, suggèrent que la ZZS ne correspond pas à une seule unité, mais est constituée de différentes écailles tectoniques qui ont subi une subduction prolongée et diachrone suivie d'une exhumation rapide et synchrone. Afin de tester cette hypothèse, j'ai daté, dans cette étude, des phengites incluses dans les grenats des méta-sédiments de deux différentes écailles tectoniques de la ZZS, afin de dater la croissance relative de ces grenats. Pour cela j'ai utilisé la méthode géochronologique basée sur la décroissance du Rb87 en Sr87. J'ai daté trois échantillons de deux différentes écailles. Les premiers deux échantillons proviennent de Triftji, au nord du Breithorn, d'une première écaille dont les méta-sédiments sont caractérisés par des bandes méta-pélitiques à grenat et des calcschistes. Le troisième échantillon a été collectionné au Riffelberg, dans une écaille dont les méta-sédiments sont essentiellement des calcschistes qui sont mélangés avec des roches mafiques et des serpentinites. Ce mélange se trouve au-dessus de la grande masse de serpentinites qui forment le Riffelhorn, le Trockenersteg et le Breithorn, et qui est connu sous le nom de la Zone de mélange de Riffelberg (Bearth, 1953). Les inclusions dans les grenats de deux échantillons méta-pélitiques de la première écaille sont datées à 44.25 ± 0.48 Ma et à 43.19 ± 0.32 Ma. Ces âges sont à peu près 4 Ma plus vieux que les âges obtenus sur les phengites provenant de la matrice de ces mêmes échantillons qui donnent des âges de 40.02 ± 0.13 Ma et 39.55 ± 0.25 Ma respectivement. Les inclusions de phengite dans les grenats appartenant à un calcschiste de la deuxième écaille ont un âge de 40.58 ± 0.24 Ma alors que les phengites de la matrice ont un âge de 39.8 ± 1.5 Ma. Pour expliquer ces différences d'âge entre les phengites incluses dans le grenat et les phengites provenant de la matrice, nous suggérons que la cristallisation de grenat ait permis d'isoler ces phengites et de les préserver de tous rééquilibrage lors de la suite du chemin métamorphique prograde, puis rétrograde. Ceci est particulièrement important pour expliquer l'absence de rééquilibrage des phengites dans des conditions de températures supérieures à la température de fermeture du système Rb/Sr pour les phengites. Les phengites en inclusions n'ayant pas pu être datées individuellement, nous interprétons l'âge de 44 Ma pour les inclusions de phengite comme un âge moyen pour l'incorporation de ces phengites dans le grenat. Ces résultats sont cohérents avec les résultats des études antérieures de la ZZS utilisant les systèmes isotopiques de Sm/Nd et Lu/Hf sur des eclogites mafiques. ils confirment qu'aux moins une partie de la ZZS a subi des conditions de pression et de température maximale il y a moins de 44 à 42 Ma avant d'être rapidement exhumée à des conditions métamorphiques du faciès schiste vert supérieur autour de 40 Ma. Cette étude détaillée des grenats a permis, également, de mettre en évidence le rôle des fluides durant le métamorphisme prograde. En effet, si tous les grenats montrent des puises de croissance et de résorption, on peut distinguer, dans différents calcschists provenant de la deuxième écaille, deux types distincts de porphyroblast de grenat en fonction de la présence ou non d'inclusions de graphite. Nous lions ces puises de croissances/résorptions ainsi que la présence ou l'absence de graphite en inclusion dans les grenats à l'infiltration de fluides dans le système, et ceci durant tous le chemin prograde mais plus particulièrement proche et éventuellement peu après du pic du métamorphisme comme le suggère l'âge de 40 Ma mesuré dans les inclusions de phengites de l'échantillon du Riffelberg. Des analyses in-situ d'isotopes d'oxygène réalisé à l'aide de la SHRIMP (Sensitive High Resolution Ion Microprobe) dans des coupes centrales des grenats indiquent des variations jusqu'à 5 %o au sein même d'un grenat. Les motifs de zonations chimiques et d'inclusions de graphite complexes, ainsi que les variations du δ180 correspondent à une croissance de grenat sous des conditions de fluides changeantes dues aux infiltrations de fluides externes. Nous lions l'origine de ces fluides aqueux aux unités ultramafiques et mafiques qui ont été subductés avec les méta-sédiments ; unités ultramafiques et mafiques qui forment la partie volumétrique la plus importante de la ZZS.

The sample processing time interval as an influential factor in flow cytometry analysis of lymphocyte subsets

The objective of this paper is to propose a protocol to analyze blood samples in yellow fever 17DD vaccinated which developed serious adverse events. We investigated whether or not the time between sample collection and sample processing could interfere in lymphocyte subset percentage, for it is often impossible to analyze blood samples immediately after collection due to transport delay from collection places to the flow cytometry facility. CD4+CD38+ T, CD8+CD38+ T, CD3+ T, CD19+ B lymphocyte subsets were analyzed by flow cytometry in nine healthy volunteers immediately after blood collection and after intervals of 24 and 48 h. The whole blood lysis method and gradient sedimentation by Histopaque were applied to isolate peripheral blood mononuclear cells for flow cytometry analyses. With the lysis method, there was no significant change in lymphocyte subset percentage between the two time intervals (24 and 48 h). In contrast, when blood samples were processed by Histopaque gradient sedimentation, time intervals for sample processing influenced the percentage in T lymphocyte subsets but not in B cells. From the results obtained, we could conclude that the whole blood lysis method is more appropriate than gradient sedimentation by Histopaque for immunophenotyping of blood samples collected after serious adverse events, due to less variation in the lymphocyte subset levels with respect to the time factor.

Use of the chicken lysozyme 5' matrix attachment region to generate high producer CHO cell lines.

Scaffold or matrix attachment region (S/MAR) genetic elements have previously been proposed to insulate transgenes from repressive effects linked to their site of integration within the host cell genome. We have evaluated their use in various stable transfection settings to increase the production of recombinant proteins such as monoclonal antibodies from Chinese hamster ovary (CHO) cell lines. Using the green fluorescent protein coding sequence, we show that S/MAR elements mediate a dual effect on the population of transfected cells. First, S/MAR elements almost fully abolish the occurrence of cell clones that express little transgene that may result from transgene integration in an unfavorable chromosomal environment. Second, they increase the overall expression of the transgene over the whole range of expression levels, allowing the detection of cells with significantly higher levels of transgene expression. An optimal setting was identified as the addition of a S/MAR element both in cis (on the transgene expression vector) and in trans (co-transfected on a separate plasmid). When used to express immunoglobulins, the S/MAR element enabled cell clones with high and stable levels of expression to be isolated following the analysis of a few cell lines generated without transgene amplification procedures.

Quantification of nicotine, cotinine, trans-3'-hydroxycotinine and varenicline in human plasma by a sensitive and specific UPLC-tandem mass-spectrometry procedure for a clinical study on smoking cessation.

A sensitive and specific ultra performance liquid chromatography-tandem mass spectrometry method for the simultaneous quantification of nicotine, its metabolites cotinine and trans-3'-hydroxycotinine and varenicline in human plasma was developed and validated. Sample preparation was realized by solid phase extraction of the target compounds and of the internal standards (nicotine-d4, cotinine-d3, trans-3'-hydroxycotinine-d3 and CP-533,633, a structural analog of varenicline) from 0.5mL of plasma, using a mixed-mode cation exchange support. Chromatographic separations were performed on a hydrophilic interaction liquid chromatography column (HILIC BEH 2.1×100mm, 1.7μm). A gradient program was used, with a 10mM ammonium formate buffer pH 3/acetonitrile mobile phase at a flow of 0.4mL/min. The compounds were detected on a triple quadrupole mass spectrometer, operated with an electrospray interface in positive ionization mode and quantification was performed using multiple reaction monitoring. Matrix effects were quantitatively evaluated with success, with coefficients of variation inferior to 8%. The procedure was fully validated according to Food and Drug Administration guidelines and to Société Française des Sciences et Techniques Pharmaceutiques. The concentration range was 2-500ng/mL for nicotine, 1-1000ng/mL for cotinine, 2-1000ng/mL for trans-3'-hydroxycotinine and 1-500ng/mL for varenicline, according to levels usually measured in plasma. Trueness (86.2-113.6%), repeatability (1.9-12.3%) and intermediate precision (4.4-15.9%) were found to be satisfactory, as well as stability in plasma. The procedure was successfully used to quantify nicotine, its metabolites and varenicline in more than 400 plasma samples from participants in a clinical study on smoking cessation.

Structural Validity of the Wechsler Intelligence Scale for Children (WISC-IV) in a French-speaking Swiss sample

The Wechsler Intelligence Scale for Children-fourth edition (i.e. WISC-IV) recognizes a four-factor scoring structure in addition to the Full Scale IQ (FSIQ) score: Verbal Comprehension (VCI), Perceptual Reasoning (PRI), Working Memory (WMI), and Processing Speed (PSI) indices. However, several authors suggested that models based on the Cattell-Horn-Carroll (CHC) theory with 5 or 6 factors provided a better fit to the data than does the current four-factor solution. By comparing the current four-factor structure to CHC-based models, this research aimed to investigate the factorial structure and the constructs underlying the WISC-IV subtest scores with French-speaking Swiss children (N = 249). To deal with this goal, confirmatory factor analyses (CFAs) were conducted. Results showed that a CHC-based model with five factors better fitted the French-Swiss data than did the current WISC-IV scoring structure. All together, these results support the hypothesis of the appropriateness of the CHC model with French-speaking children.

Paleoparasitological report on Ascaris aDNA from an ancient East Asian sample

In this study, Ascaris DNA was extracted and sequenced from a medieval archaeological sample in Korea. While Ascaris eggs were confirmed to be of human origin by archaeological evidence, it was not possible to pinpoint the exact species due to close genetic relationships among them. Despite this shortcoming, this is the first Ascaris ancient DNA (aDNA) report from a medieval Asian country and thus will expand the scope of Ascaris aDNA research.

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry and PCR-based rapid diagnosis of Staphylococcus aureus bacteraemia.

Effective empirical treatment is of paramount importance to improve the outcome of patients with Staphylococcus aureus bacteraemia. We aimed to evaluate a PCR-based rapid diagnosis of methicillin resistance (GeneXpert MRSA) after early detection of S. aureus bacteraemia using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Patients with a first episode of S. aureus bacteraemia identified using MALDI-TOF MS were randomized in a prospective interventional open study between October 2010 and August 2012. In the control group, antibiotic susceptibility testing was performed after MALDI-TOF MS identification on blood culture pellets. In the intervention group, a GeneXpert MRSA was performed after S. aureus identification. The primary outcome was the performance of GeneXpert MRSA directly on blood cultures. We then assessed the impact of early diagnosis of methicillin resistance on the empirical treatment. In all, 197 episodes of S. aureus bacteraemia were included in the study, of which 106 were included in the intervention group. Median time from MALDI-TOF MS identification to GeneXpert MRSA result was 97 min (range 25-250). Detection of methicillin resistance using GeneXpert MRSA had a sensitivity of 99% and a specificity of 100%. There was less unnecessary coverage of MRSA in the intervention group (17.1% versus 29.2%, p 0.09). GeneXpert MRSA was highly reliable in diagnosing methicillin resistance when performed directly on positive blood cultures. This could help to avoid unnecessary prescriptions of anti-MRSA agents and promote the introduction of earlier adequate coverage in unsuspected cases.

A survey addressing the fundamental matrix estimation problem

Epipolar geometry is a key point in computer vision and the fundamental matrix estimation is the only way to compute it. This article surveys several methods of fundamental matrix estimation which have been classified into linear methods, iterative methods and robust methods. All of these methods have been programmed and their accuracy analysed using real images. A summary, accompanied with experimental results, is given

Assessing the Precision of Compositional Data in a Stratified Double Stage Cluster Sample: Application to the Swiss Earnings Structure Survey

Precision of released figures is not only an important quality feature of official statistics,it is also essential for a good understanding of the data. In this paper we show a casestudy of how precision could be conveyed if the multivariate nature of data has to betaken into account. In the official release of the Swiss earnings structure survey, the totalsalary is broken down into several wage components. We follow Aitchison's approachfor the analysis of compositional data, which is based on logratios of components. Wefirst present diferent multivariate analyses of the compositional data whereby the wagecomponents are broken down by economic activity classes. Then we propose a numberof ways to assess precision

Compositional evolution with mass transfer in closed systems

Evolution of compositions in time, space, temperature or other covariates is frequentin practice. For instance, the radioactive decomposition of a sample changes its composition with time. Some of the involved isotopes decompose into other isotopes of thesample, thus producing a transfer of mass from some components to other ones, butpreserving the total mass present in the system. This evolution is traditionally modelledas a system of ordinary di erential equations of the mass of each component. However,this kind of evolution can be decomposed into a compositional change, expressed interms of simplicial derivatives, and a mass evolution (constant in this example). A rst result is that the simplicial system of di erential equations is non-linear, despiteof some subcompositions behaving linearly.The goal is to study the characteristics of such simplicial systems of di erential equa-tions such as linearity and stability. This is performed extracting the compositional differential equations from the mass equations. Then, simplicial derivatives are expressedin coordinates of the simplex, thus reducing the problem to the standard theory ofsystems of di erential equations, including stability. The characterisation of stabilityof these non-linear systems relays on the linearisation of the system of di erential equations at the stationary point, if any. The eigenvelues of the linearised matrix and theassociated behaviour of the orbits are the main tools. For a three component system,these orbits can be plotted both in coordinates of the simplex or in a ternary diagram.A characterisation of processes with transfer of mass in closed systems in terms of stability is thus concluded. Two examples are presented for illustration, one of them is aradioactive decay

The ability of haemolysins expressed by atypical enteropathogenic Escherichia coli to bind to extracellular matrix components

Typical and atypical enteropathogenic Escherichia coli (EPEC) are considered important bacterial causes of diarrhoea. Considering the repertoire of virulence genes, atypical EPEC (aEPEC) is a heterogeneous group, harbouring genes that are found in other diarrheagenic E. coli pathotypes, such as those encoding haemolysins. Haemolysins are cytolytic toxins that lyse host cells disrupting the function of the plasma membrane. In addition, these cytolysins mediate a connection to vascular tissue and/or blood components, such as plasma and cellular fibronectin. Therefore, we investigated the haemolytic activity of 72 aEPEC isolates and determined the correlation of this phenotype with the presence of genes encoding enterohaemolysins (Ehly) and cytolysin A (ClyA). In addition, the correlation between the expression of haemolysins and the ability of these secreted proteins to adhere to extracellular matrix (ECM) components was also assessed in this study. Our findings demonstrate that a subset of aEPEC presents haemolytic activity due to the expression of Ehlys and/or ClyA and that this activity is closely related to the ability of these isolates to bind to ECM components.

Effect of serum sample inactivation on the performance of latex agglutination test for paracoccidioidomycosis serodiagnosis

Paracoccidioidomycosis is diagnosed from the direct observation of the causative agent, but serology can facilitate and decrease the time required for diagnosis. The objective of this study was to determine the influence of serum sample inactivation on the performance of the latex agglutination test (LAT) for detecting antibodies against Paracoccidioides brasiliensis. The sensitivity of LAT from inactivated or non-inactivated samples was 73% and 83%, respectively and the LAT selectivity was 79% and 90%, respectively. The LAT evaluated here was no more specific than the double-immunodiffusion assay. We suggest the investigation of other methods for improving the LAT, such as the use of deglycosylated antigen.

Disruption of the peritrophic matrix by exogenous chitinase feeding reduces fecundity in Lutzomyia longipalpis females

Lutzomyia longipalpis is the most important vector of visceral leishmaniasis in Brazil. When female sandflies feed on blood, a peritrophic matrix (PM) is formed around the blood bolus. The PM is secreted by midgut cells and composed of proteins, glycoproteins and chitin microfibrils. The PM functions as both a physical barrier against pathogens present in the food bolus and blood meal digestion regulator. Previous studies of mosquitoes and sandflies have shown that the absence of a PM, resulting from adding an exogenous chitinase to the blood meal, accelerates digestion. In the present study, we analysed biological factors associated with the presence of a PM in L. longipalpis females. Insects fed blood containing chitinase (BCC) accelerated egg-laying relative to a control group fed blood without chitinase. However, in the BCC-fed insects, the number of females that died without laying eggs was higher and the number of eggs laid per female was lower. The eggs in both groups were viable and generated adults. Based on these data, we suggest that the absence of a PM accelerates nutrient acquisition, which results in premature egg production and oviposition; however, the absence of a PM reduces the total number of eggs laid per female. Reduced fecundity in the absence of a PM may be due to inefficient nutrient conversion or the loss of the protective role of the PM.

Can Mosquito Magnet® substitute for human-landing catches to sample anopheline populations?

The efficiency of the Mosquito Magnet Liberty PlusTM (MMLP) trap was evaluated in comparison to human-landing catches (HLCs) to sample anopheline populations in Jabillal, state of Bolivar, southern Venezuela. The village comprised 37 houses and a population of 101; malaria in this village is primarily due to Plasmodium vivax and the Annual Parasite Index is 316.8 per 1,000 population. A longitudinal study was conducted between June 2008-January 2009 for three nights per month every two months between 17:30 pm-21:30 pm, a time when biting mosquitoes are most active. Anopheles darlingi and Anopheles nuneztovari were the most common species collected by both methods, whereas Anopheles marajoara was more abundant according to the HLC method. The MMLP trap was more efficient for collecting An. nuneztovari [63%, confidence interval (CI): 2.53] than for collecting An. darlingi (31%, CI: 1.57). There were significant correlations (p < 0.01) between the two methods for An. darlingi [Pearson correlation (R²) = 0.65] and An. nuneztovari (R² = 0.48). These preliminary results are encouraging for further investigations of the use of the MMLP trap for monitoring anopheline populations in remote malaria-endemic areas in the Amazon Basin.