Study and suppression of the microstructural anisotropy generated during the consolidation of a carbonyl iron powder by field-assisted hot pressing

Published OnlineA spherical carbonyl iron powder was consolidated by the field-assisted hot pressing technique using graphite tools at two different temperatures, both above the austenitizing temperature. The microstructures obtained exhibited a compositional gradient in carbon along the consolidated material. Thus, the outer rim of the cylindrical samples was composed of cementite and pearlite that gradually turned to pearlite, leading to a fully ferritic microstructure at the core of the sample. The increase in the temperature has led to a higher introduction of carbon within the sample. The interposition of a thin tungsten foil between the graphite die/punches and the powders has significantly reduced the diffusion of the carbon through the iron matrix and has suppressed the microstructural anisotropy.Publicad

Estrogen Receptor Alpha as a Key Target of Red Wine Polyphenols Action on the Endothelium

BACKGROUND: A greater reduction in cardiovascular risk and vascular protection associated with diet rich in polyphenols are generally accepted; however, the molecular targets for polyphenols effects remain unknown. Meanwhile evidences in the literature have enlightened, not only structural similarities between estrogens and polyphenols known as phytoestrogens, but also in their vascular effects. We hypothesized that alpha isoform of estrogen receptor (ERalpha) could be involved in the transduction of the vascular benefits of polyphenols. METHODOLOGY/PRINCIPAL FINDINGS: Here, we used ERalpha deficient mice to show that endothelium-dependent vasorelaxation induced either by red wine polyphenol extract, Provinols, or delphinidin, an anthocyanin that possesses similar pharmacological profile, is mediated by ERalpha. Indeed, Provinols, delphinidin and ERalpha agonists, 17-beta-estradiol and PPT, are able to induce endothelial vasodilatation in aorta from ERalpha Wild-Type but not from Knock-Out mice, by activation of nitric oxide (NO) pathway in endothelial cells. Besides, silencing the effects of ERalpha completely prevented the effects of Provinols and delphinidin to activate NO pathway (Src, ERK 1/2, eNOS, caveolin-1) leading to NO production. Furthermore, direct interaction between delphinidin and ERalpha activator site is demonstrated using both binding assay and docking. Most interestingly, the ability of short term oral administration of Provinols to decrease response to serotonin and to enhance sensitivity of the endothelium-dependent relaxation to acetylcholine, associated with concomitant increased NO production and decreased superoxide anions, was completely blunted in ERalpha deficient mice. CONCLUSIONS/SIGNIFICANCE: This study provides evidence that red wine polyphenols, especially delphinidin, exert their endothelial benefits via ERalpha activation. It is a major breakthrough bringing new insights of the potential therapeutic of polyphenols against cardiovascular pathologies

"Sprache ist der Boden, auf dem wir tanzen"- Mehr-Sprachlichkeit im Theaterstück ROSE ROSE ROSE von Malin Axelsson und Karin Serres

Trotz einer inzwischen langen Tradition von Mehrsprachigkeit im Theater scheinen deren Ausdruckspotentiale und möglichen Funktionen bei weitem noch nicht ausgeschöpft zu sein. Das Theaterstück ROSE ROSE ROSE von Malin Axelsson und Karin Serres (2015), in dem auf den ersten Blick die Verwendung von schwedischen, französischen und englischen Redeabschnitten auffällt, scheint kein Novum darzustellen, zumal es sich auch hinsichtlich anderer Aspekte in die Tradition einer avantgardistischen Theaterpraxis einreiht, die insbesondere das schwedische Jugendtheater stark geprägt hat. Doch bei einer genaueren Analyse des Textes und seiner spezifischen sprachlichen Beschaffenheit zeigt sich schnell, auf welch vielfältige Weise sich hier Mehrsprachigkeit bzw. Mehr-Sprachlichkeit manifestiert und dass diese – auf verschiedenen Ebenen – eine zentrale Rolle im Stück übernimmt. Sie bildet die einmalige ›Gestalt‹ des Stückes heraus, konstituiert seinen Experimentierraum und erweist sich zugleich als ›Akteurin‹ im gesamten Handlungskomplex. Dies versuchen wir in unserem Beitrag darzulegen, indem wir verschiedene Verfahren der Mehr-Sprachlichkeit im Text herausstellen und exemplarisch eine detailliertere Analyse eines ausgewählten Kapitels durchführen

Korrosionsmechanismen von Chrom/Nickelschmelzen an Verdampferwerkstoffen: Poster zur DKG Tagung, Hermsdorf, 22.-24.03.2010

Die Korrosionsmechanismen an konventionellen hBN/TiB2 Aluminiumverdampfermaterialien durch Chrom/Nickelschmelzen werden im Vergleich zu neu entwickelten Werstoffen auf Basis des gleichen Materialsystems verglichen und der chemische und zeitliche Ablauf der Korrosion durch Chrom/Nickel beschrieben

Influence of Mg-PSZ particle size on the low cycle fatigue behaviour of steel matrix composites

Metal matrix composites (MMCs) are considered as promising materials because of their interesting properties in terms of strength and wear resistance combined with a reasonable ductility. The development of MMCs based on high-alloyed austenitic steels with TRIP- (transformation-induced plasticity) and/or TWiP- (twinning-induced plasticity) effect reinforced with MgO-partially stabilized zirconia gives the possibility to combine materials which show deformation-induced and stress-assisted martensitic transformations. In the present work, TWIP steel matrix composites reinforced with 10 vol% MgO-partially stabilized zirconia (Mg-PSZ) were produced using the hot pressing technique. Mg-PSZ powders with different particle size distributions were used as reinforcing phase. The steel matrix is m ade of the high-alloyed austenitic steel grade 16Cr-6Mn-9Ni (nominal concentration in wt%) which can show under certain conditions the TWIP-effect MMCs and the unreinforced steel were cyclically deformed under total strain control in order to study the influence of the Mg-PSZ particle size on the low cycle fatigue behaviour of the TWIP steel matrix composites including the discussion of cyclic hardening and softening and consequences on fatigue lives. The microstructural evolution under cyclic loading was characterized using scanning electron microscopy techniques

Reliable in vitro measurement of nitric oxide released from endothelial cells using low concentrations of the fluorescent probe 4,5-diaminofluorescein

Abstract4,5-Diaminofluorescein (DAF-2) and its membrane-permeable derivate DAF-2 diacetate are fluorescent probes that have been developed to perform real-time biological detection of nitric oxide (NO). Their use for intracellular imaging, however, has recently been seriously questioned and data using DAF-2 for extracellular NO detection at low levels, as for example released from endothelial cells, are rare. Here we show that a reliable detection of low levels of NO in biological systems by DAF-2 is possible (a) by using low DAF-2 concentrations (0.1 μM) and (b) by subtracting the DAF-2 auto-fluorescence from the measured total fluorescence. The described method allows easy real-time detection of endothelial NO formation

Preparation and properties of B6O/TiB2-composites

B 6O/TiB 2 composites with varying compositions were produced by FAST/SPS at temperatures between 1850 and 1900°C following a non-reactive or a reactive sintering route. The densification, phase and microstructure formation and the mechanical and thermal properties were investigated. The comparison to an also investigated pure B 6O material showed that the addition of TiB 2 in a non-reactive sintering route promotes the B 6O densification. Further improvement was obtained by sintering reactive B-TiO 2 mixtures which also results in materials with a finer grain size and thus in enhanced mechanical properties. The fracture toughness was significantly improved in all composites and is up to 4.0MPam 1/2 (SEVNB) and 2.6-5.0MPam 1/2 (IF method) while simultaneously a high hardness of up to 36GPa (HV 0.4) and 28GPa (HV 5) could be preserved. The high temperature properties at 1000°C of hardness, thermal conductivity and CTE were up to 20GPa, 18W/mK and 6.63×10 -6/K, respectively