Gd-Kontrastmittel werden in der Medizin für die Magnetresonanztomographie (MRT) benötigt, um einen besseren Bildkontrast zu erzielen. Nach der Anwendung gelangen diese Arzneimittel über das Abwasser in die Klärwerke und von dort in die jeweiligen anliegenden Oberflächengewässer. Somit wird es notwendig, den Verbleib der Gd-MRT-Kontrastmittel in der Umwelt zu verfolgen und aufzuklären. In dieser Arbeit werden für die Analyse von Umweltproben Methoden zur Speziesanalytik von Gd-Kontrastmitteln entwickelt und optimiert. Hierbei wird u.a. die Zwitterionische Hydrophile Interaktionschromatographie (HILIC) verwendet, die mit einer Induktiv- gekoppelten Plasma – Massenspektrometrie (ICP-MS) gekoppelt ist. / Gd based contrast agents are used for medical magnetic resonance imaging (MRI) to enhance the contrast of the image. After application and excretion, the drugs pass through the wastewater treatment plant (WWTP) and make their way into the surrounding surface water bodies. This makes it necessary to monitor the fate of the Gd based contrast agents in the environment. In this work, methods for speciation analysis of Gd based contrast agents in environmental samples were developed and optimised. For this purpose i.a. zwitterionic hydrophilic interaction chromatography (HILIC) is used, which is hyphenated with inductively coupled plasma mass spectrometry (ICP-MS).

The effect of individual additions of calcium oxide (CaO), Gd, Nd and Y was investigated on the microstructure, mechanical properties and corrosion resistance of the as-cast ZK40 alloy. The microstructural features were analised using optical, scanning and transmission electron microscopy, X-ray diffraction and Scanning Kelvin Atomic Probe Force Microscopy. The compressive and tensile behaviours of the as-cast alloys at room temperature were investigated. Electrochemical Impedance Spectroscopy, hydrogen evolution and weight loss under immersion in 0.5 wt.% NaCl solution were used to evaluate the corrosion behaviour. The results of the mechanical and corrosion tests were correlated with the microstructures. The 2 wt.% Gd addition enhanced the ductility, while the Nd addition resulted in deterioration in mechanical properties. The addition of 2 wt.% Gd and 1 wt.% Y resulted in the improvement of the ductility. The addition of CaO did not affect the mechanical properties while the 2 wt.% Nd deteriorate it. The 1 wt.% Y addition enhanced the ductility. The CaO addition did not caused enhancement in mechanical properties. The corrosion behaviour was enhanced with the addition of CaO and Gd. The modification of ZK40 with Gd opens up new perspectives in the development of Mg-Zn based alloys. / O efeito da adição individual de óxido de cálcio (CaO), Gd, Nd e Y foi investigado na microestrutura, propriedades mecânicas e resistência à corrosão de ligas ZK40 fundidas. As características microestruturais foram analisadas via microscopia óptica, microscopia eletrônica de varredura, microscopia eletrônica de transmissão, difração de Raios-X e \"Scanning Kelvin Atomic Probe Force Microscopy\". O comportamento à compressão e à tração das ligas à temperatura ambiente foi investigado. Espectroscopia eletroquímica de impedância, evolução de hidrogênio e ensaios de imersão em solução de 0.5% em peso de NaCl foram utilizados para avaliar a resistência à corrosão. Os resultados dos ensaios mecânicos e corrosão foram relacionados com a microestrutura. A adição de 2% em peso de Gd melhorou a ductilidade, ao passo que a adição de Nd resultou na piora das propriedades mecânicas. A adição de 2% em peso de Gd e 1% em peso de Y resultou na melhora da ductilidade. A adição de 1% em peso de Y causou uma melhora na ductilidade e a adição de CaO não teve impacto benéfico nas propriedades mecânicas. A resistência à corrosão foi melhorada com a adição de CaO e Gd. A modificação da liga ZK40 com a adição de Gd abre novas perspectivas no desenvolvimento de ligas Mg-Zn.

Les nano-composés de type Sn1-xTaxO2 (0 ≤ x ≤ 0,03) ont été étudiés en vue de leurs propriétés thermoélectriques. Une méthode de co-précipitation a été utilisée pour synthétiser des nano-poudres ayant une taille des grains moyenne d’environ 3 nm. L’étude structurale et microstructurale a suggéré une limite de solubilité pour le Ta de 0,008 ≤ x < 0,010. Ces nano-poudres ont été ensuite densifiées par Spark Plasma Sintering, avec des compacités atteignant ~ 95%. Le dopage en Ta a permis une amélioration des propriétés thermoélectriques du SnO2 et, en accord avec la limite de solubilité, une valeur maximale du facteur de mérite de 4,7x10-5 K-1 a été observée pour l’échantillon x = 0,008. De plus, nous avons démontré qu’une diminution de la taille des grains permettait d’améliorer le coefficient Seebeck, de diminuer la conductivité thermique, mais conduisait à une diminution de la conductivité électrique. La stabilité des oxydes, notamment à l'échelle nanométrique, est remise en question par des caractérisations physico-chimiques. Partant de ces matériaux à base de SnO2, un nano-composite (ZnO-SnO2) a été étudié. Le composé Zn1-xGdxO (0 ≤ x ≤ 0,03) a été préparé par la méthode de Péchini et caractérisé en comparant avec d’autres matériaux à base de ZnO. Un premier test de nano-composite M30 (30% en masse Sn0.996Ta0.004O2 et 70% en masse Zn0.997Gd0.003O) a été mené. Le résultat obtenu a montré qu’une concentration de nano-inclusion Sn0.996Ta0.004O2 de 30 % ne permettait pas d’améliorer les propriétés thermoélectriques du nano-composite M30, par rapport aux matériaux de départ. / The nano-compound Sn1-xTaxO2 (0 ≤ x ≤ 0.03) was studied with a view to their thermoelectric properties. A method of co-precipitation was used to synthesize nano-powders having an average grain size of about 3 nm. The structural and microstructural study suggested a solid solubility limit of 0.008 ≤ x < 0.010. These nano-powders were then densified by Spark Plasma Sintering, with density reaching ~ 95%. The doping of Ta improved the thermoelectric properties, and in good agreement with the solubility limit, a maximum value of the factor of merit of 4.7x10-5 K-1 was observed for the sample x = 0.008. The stability of oxides, particularly at the nanoscale, is questioned by physicochemical characterizations. From these SnO2-based materials, a nano-composite (ZnO-SnO2) was studied. The compound Zn1-xGdxO (0 ≤ x ≤ 0.03) was prepared by the method of Pechini and characterized by comparing with other ZnO-based materials. A first test of nano-composite M30 (30 wt% Sn0.996Ta0.004O2 and 70 wt% Zn0.997Gd0.003O) was conducted. The result showed that a concentration of 30% nano-inclusion Sn0.996Ta0.004O2 did not allow to improve the thermoelectric properties of nano-composite M30, compared to the starting materials.

This article describes the compositional depth profiling (CDP) of diamond-like carbon (DLC) layers by Glow Discharge-Optical Emission Spectrometry (GD-OES). The DLC layers were deposited on flat steel samples. Analysis by using a Charge Coupled Device (CCD) GD-OES instrument revealed saturation effects of the carbon lines at 156 nm and 165 nm. Therefore, the application of these lines for CDP of DLC layers is not possible. A third line at 193 nm was not affected by this saturation effect and is therefore a good choice for calibration. A second effect was observed as a non-flat crater in combination with large differences of the sputtering rate factor of the substrate (1.1) and the DLC (0.032) led to an unusual behaviour at the interface between the DLC layer and substrate. Both measurements of the crater shape and of the sputtered coating weight up to the interface and just behind it showed clearly that about 30% of the DLC layer remains at the crater edge, once the crater centre reaches the interface. This was found to be the main reason for the incorrect DLC-layer thickness, if the intersection between the carbon and iron concentration was used as a measure for the end of the DLC layer.

Die geometrische Produktspezifikation (GPS) ist für Unternehmen eine wesentliche Triebfeder um sich in Konstruktions- und Entwicklungsprozessen neu auszurichten. Mit der 3-dimensionalen Bemaßung an der CAD-Geometrie sollen alle Aspekte der Geometriebeschreibung datenneutral umgesetzt werden. Dazu gehören Toleranzdefinitionen die den Anspruch der Funktion, der Fertigbarkeit und der Messtechnik erfüllen. Die verfügbaren Werkzeuge zur normgerechten Toleranzdefinition am 3D-Teil haben sich in Creo 4 mit dem GD&T Advisor nochmals deutlich erweitert. Dies wird in diesem Vortrag mit dem Fokus auf die Toleranzanalyse in Creo 4 und der neuen CETOL Version 9 aufgezeigt.

L’utilisation de plus en plus fréquente des agents de contraste à base de Gd (AC-Gd) au cours des examens d’Imagerie par Résonnance Magnétique (IRM), engendre le rejet de ces produits pharmaceutiques dans les eaux usées retraitées en STation d’EPuration (STEP). En l’absence de retraitement spécifique de ces AC-Gd en STEP, ils sont rejetés dans le milieu aquatique, où de nombreuses études ont relevé leur présence aussi bien dans les eaux de surface que dans les eaux souterraines et jusqu’à l’eau du robinet. Le manque de connaissances concernant les effets des AC-Gd suite à leur rejet a mis en évidence la nécessité d’étudier leurs impacts environnementaux sur les organismes vivants dans les milieux aquatiques. Dans ce contexte, nous avons choisi de déterminer les concentrations en Gd d’origine anthropique à proximité de rejets de STEP et de zones de captage en eau potable situés en région Lorraine. Nos mesures ont permis de montrer la présence Gd d’origine anthropique sur l’ensemble des échantillons prélevés, avec des concentrations mesurées comprises de quelques ng(Gd)/L à quelques dizaines de µg(Gd)/L. Ces concentrations de Gd anthropique seraient dues à la présence d’AC-Gd. Nous nous sommes plus particulièrement intéressés aux effets de l’AC-Gd le plus stable et l’un des plus fréquemment commercialisé : le Gd-DOTA (Dotarem®). Pour cela, nous avons choisis plusieurs espèces représentatives des taxons rencontrés dans les cours d’eau Lorrains. Des essais ont été menés en conditions contrôlées de laboratoire afin de mesurer l’accumulation du Gd-DOTA dans les tissus et les effets de l’AC-Gd ont été appréhendés au travers de mesures de croissance, de reproduction et de mortalité au niveau individuel chez les microalgues vertes unicellulaires (Chlorella vulgaris et Pseudokirchneriella subcapitata), chez un microcrustacé (Daphnia magna) et chez un vertébré aquatique (Danio rerio) exposés à des concentrations en Gd-DOTA réalistes d’un point de vue environnemental. L’accumulation du Gd-DOTA a aussi été mesurée chez les bivalves (Corbicula fluminea et Dresseina rostriformis bugensis) et comparée à des mesures d’accumulation du Gd in situ. Les réponses physiologiques des bivalves ont été évaluées à l’aide d’une batterie de 11 biomarqueurs dans leurs branchies et leur glande digestive. Les effets de l’AC-Gd ont également été étudiés in vitro sur des fibroblastes de D. rerio (cellules ZF4 - ATCC-2050). Nos travaux ont montré que les AC-Gd et le Gd-DOTA en particulier étaient responsables d’effets écotoxiques indirects à différents niveaux d’organisation biologiques. Seuls les bivalves accumulent le Gd-DOTA mais tous les individus semblent mettre en place des mécanismes de dépuration pour parer à la toxicité de l’AC-Gd. Les résultats obtenus au cours de cette recherche ont confirmé la nécessité d’un suivi des concentrations en AC-Gd dans le milieu aquatique et la nécessité d’approfondir les études de l’écotoxicité de ces produits pharmaceutiques. Ceci pourra aboutir à une évaluation pertinente de leur risque environnemental et de proposer des solutions pour la gestion environnementale de ces composés / The increasing use of Gadolinium-based Contrast Agents (Gd-CA) for Magnetic Resonance Imaging (MRI) results in their rejection in Waste Water Treatment Plants (WWTPs). Due to the lack of specific recycling process in European WWTPs, these pharmaceutical produces enter the aquatic environment from river to tap water. The effects of Gd-CA in aquatic media have been not studied yet. The lack of knowledge about these effects highlighted the need to study their environmental impacts on aquatic organisms. In this context, we decided to measure anthropogenic concentrations of Gd in the aquatic environment in the Lorraine region (France) closed to WWTPs outputs and catchment areas used for drinking water. Our measurements underlined the presence of anthropogenic Gd on all the collected samples at concentrations ranging from few ng/L to several dozen of µg/L. In this research we focused on the effects of the most frequently used Gd-CA, the gadoteric acid (Gd-DOTA - Dotarem®) which is also the most stable one. Several representative species of aquatic environment were selected for ecotoxicological assays: i.e. unicellular green microalgae (Chlorella vulgaris and Pseudokirchneriella subcapitata), microcrustacean (Daphnia magna) and aquatic vertebrate (Danio rerio). Assays were conducted in laboratory under controlled conditions as well as in situ. Gd-DOTA accumulation was measured in the tissues of the different organisms. Environmental realistic concentrations of Gd-CA were used to assess their effects at the individual level by means of growth, reproduction and mortality measurements. The Gd-DOTA accumulation was also measured in bivalves’ tissues (Corbicula fluminea and Dresseina rostriformis bugensis) and compared to Gd ones in situ in these organisms. Physiological responses were assessed based on a battery of 11 complementary biomarkers measured in the digestive gland and in the gills of both bivalve species. At cellular level, the effects of Gd-DOTA were studied in vitro on D. rerio fibroblasts (ZF4 – ATCC-2050). Indirect ecotoxicological effects of Gd-CA and of Gd-DOTA especially have been highlighted at all biological levels. Accumulation of Gd-DOTA was observed in bivalves only, but defense systems were mobilized in all organisms to limit toxicity. Our results demonstrated that following both research on ecotoxicological effects of the Gd-CA and evolution of their concentrations in aquatic ecosystem are necessary to assess more precisely their environmental risk and to propose solutions for their environmental management

Estrogens have the ability to alter the immune system. Diethylstilbestrol (DES), asynthetic estrogen, is known to have estrogenic activity and induce thymic alterations.We investigated the mechanism by which DES is able to alter T cells and thus theimmune system. First, we studied the effect of DES on mature T cells by using the T cellleukemia cell line, Jurkat. We found that DES treatment reduced cell viability andincreased apoptosis. Additionally, apoptosis was found to involve both death receptorand mitochondria1 pathways. Furthermore, estrogen receptor beta was found to beexpressed in these cells and increased following DES treatment. Secondly, we studiedthe effect of DES on developing T cells using two different mouse models, timed pregnant and HY-TCR transgenic. The pregnant mouse model showed that DESexposure in utero reduced thymic cell viability and induced apoptosis at gestational day(gd)-17. Apoptosis was found to involve the death receptor pathway. Additionally,alterations in T cell subsets was most pronounced at gd-17 as well. The HY-TCR tgmouse model showed that DES exposure altered both positive and negative selection of Tcells. Furthermore, DES was found to alter the ability of T cells to proliferate during animmune response. Finally, we studied the intrathymic interaction between thymicstromal cells and thymic T cells. We found that cel1:cell interaction was important forinducing T cell apoptosis in the thymus. Additionally, FasL expression was increased onthymic stromal cells following DES exposure. Furthermore, the presence of both FasL onstromal cells and Fas on T cells was important for inducing T cell apoptosis in thethymus.

<p> </p><p>Acquired data from dynamic contrast enhanced MRI measurements can be used to non-invasively assess tumour vascular characteristics through pharmacokinetic modelling. The modelling requires an arterial input function which is the concentration of contrast agent in the blood reaching the volume of interest as a function of time. The aim of this work is testing and optimizing a turboFLASH sequence to appraise its suitability for measuring the arterial input function by measuring phase.</p><p>Contrast concentration measurements in a phantom were done with both phase and relaxivity techniques. The results were compared to simulations of the experiment conditions to compare the conformance. The results using the phase technique were promising, and the method was carried on to in-vivo testing. The in-vivo data displayed a large signal loss which motivated a new phantom experiment to examine the cause of this signal reduction. Dynamic measurements were made in a phantom with pulsatile flow to mimic a blood vessel with a somewhat modified turboFLASH sequence. The conclusions drawn from analyzing the data were used to further improve the sequence and this modified turboFLASH sequence was tested in an in-vivo experiment. The obtained concentration curve showed significant improvement and was deemed to be a good representation of the true blood concentration.</p><p>The conclusion is that phase measurements can be recommended over relaxivity based measurements. This recommendation holds for using a slice selective saturation recovery turboFLASH sequence and measuring the arterial input function in the neck. Other areas of application need more thorough testing.</p><p> </p>

In a communication system, the group delay variation (GDV) causes the distortion of signal and the degradation of symbol error rate. Usually, the compensation of group delay (GD) utilizing positive group delay (PGD) results in further propagation delay. Therefore, this research studies the negative group delay (NGD) behavior of metamaterial. Through analyzing the effects on GD caused by poles and zeros of circuit, the group delay circuit capable of switching between NGD and PGD is presented. Further, adjustable negative group delay circuits (NGDCs) are designed based on the concept of poles and zero. The NGD generated by NGDC is used to achieve the equalization of GD and recover the distorted signal in time domain. Additionally, owing to the limited frequency band of communication, a filter with high selectivity is required to utilize the available bandwidth. The character of left-handed metamaterial is applied to the design of filter for reducing the size and cost of traditional microstrip line filters with high selectivity. Under the balanced condition, composite right/left-handed (CRLH) transmission line behaves right- and left- handed characteristics in different frequency bands. Thus, a coplanar waveguide (CPW) filter with high selectivity, size reduction and low cost is presented utilizing such a CRLH structure.

Les langues, une ressource économique ? Les problèmes de la variété linguistique et des choix linguistiques sont abordés par les entreprises et par leurs salariés sous le double aspect de la communication externe et de la communication interne. Ces questions, qui n'ont fait l'objet jusqu' à présent que d'études statistico-quantitatives, seront traitées dans cette contribution à travers une série d'études de cas qualitatives, couvrant une vaste gamme de secteurs, de branches et de tailles d'entreprises. Une vue d'ensemble de toutes ces études de cas nous permettra de tirer des conclusions générales sur les particularités des choix et politiques linguistiques en milieu d'affaires, que ce soit le mélange spécifique entre adaptation et standardisation, le cas spécial des négociations, les conséquences de la domination d'un certain marché, l'importance de l'organisation des canaux de distribution, l'impact du rapport coûts-bénéfices ainsi que des expériences linguistiques personnelles des hauts responsables. Nous nous pencherons également sur la question de la méthodologie de telles enquêtes, sur les positions inégales du vendeur et de l'acheteur et sur le trade-off entre communication externe et interne dans les entreprises. (abrégé) / Series: WU Online Papers in International Business Communication / Series One: Intercultural Communication and Language Learning