University of Münster

About: University of Münster is a education organization based out in Münster, Germany. It is known for research contribution in the topics: Population & Transplantation. The organization has 35609 authors who have published 69059 publications receiving 2278534 citations. The organization is also known as: University of Munster & University of Muenster.

A Cenozoic record of the equatorial Pacific carbonate compensation depth

Abstract: Atmospheric carbon dioxide concentrations and climate are regulated on geological timescales by the balance between carbon input from volcanic and metamorphic outgassing and its removal by weathering feedbacks; these feedbacks involve the erosion of silicate rocks and organic-carbon-bearing rocks. The integrated effect of these processes is reflected in the calcium carbonate compensation depth, which is the oceanic depth at which calcium carbonate is dissolved. Here we present a carbonate accumulation record that covers the past 53 million years from a depth transect in the equatorial Pacific Ocean. The carbonate compensation depth tracks long-term ocean cooling, deepening from 3.0-3.5 kilometres during the early Cenozoic (approximately 55 million years ago) to 4.6 kilometres at present, consistent with an overall Cenozoic increase in weathering. We find large superimposed fluctuations in carbonate compensation depth during the middle and late Eocene. Using Earth system models, we identify changes in weathering and the mode of organic-carbon delivery as two key processes to explain these large-scale Eocene fluctuations of the carbonate compensation depth.

Mechanism of IFN-γ-induced Endocytosis of Tight Junction Proteins: Myosin II-dependent Vacuolarization of the Apical Plasma Membrane

Abstract: Disruption of epithelial barrier by proinflammatory cytokines such as IFN-gamma represents a major pathophysiological consequence of intestinal inflammation. We have previously shown that IFN-gamma increases paracellular permeability in model T84 epithelial cells by inducing endocytosis of tight junction (TJ) proteins occludin, JAM-A, and claudin-1. The present study was designed to dissect mechanisms of IFN-gamma-induced endocytosis of epithelial TJ proteins. IFN-gamma treatment of T84 cells resulted in internalization of TJ proteins into large actin-coated vacuoles that originated from the apical plasma membrane and resembled the vacuolar apical compartment (VAC) previously observed in epithelial cells that lose cell polarity. The IFN-gamma dependent formation of VACs required ATPase activity of a myosin II motor but was not dependent on rapid turnover of F-actin. In addition, activated myosin II was observed to colocalize with VACs after IFN-gamma exposure. Pharmacological analyses revealed that formation of VACs and endocytosis of TJ proteins was mediated by Rho-associated kinase (ROCK) but not myosin light chain kinase (MLCK). Furthermore, IFN-gamma treatment resulted in activation of Rho GTPase and induced expressional up-regulation of ROCK. These results, for the first time, suggest that IFN-gamma induces endocytosis of epithelial TJ proteins via RhoA/ROCK-mediated, myosin II-dependent formation of VACs.

Zustandsdiagramm und thermodynamisches Verhalten der Systeme Pd/H2 und Pd/D2 bei normalen Temperaturen; H/D‐Trenneffekte

Abstract: Mit Hilfe von Ubertragungskatalysatoren (UH3-, UD3-, Cu-Pulver) wurden an kompaktem Pd (0,3 und 0,15 mm Folien) Aufbau- und Abbauisothermen mit H2 und D2 gemessen; Temperaturen + 75 bis −78 °C, Drucke 760 bis 10−3 Torr, Atomzahlverhaltnisse n (= H/Pd bzw. D/Pd) von 0,001 bis 0,83. Aus den Messungen im Bereich der α-Phase wurden die chemischen Potentiale des gelosten H bzw. D im Grenzzustand n 0 und ihre auf eine Attraktionswechselwirkung zuruckgehenden, der Konzentration proportionalen Zusatzanteile berechnet. Im Bereich der β-Phase wurden die entsprechenden Zusatzanteile ermittelt. Sie treten hier formal als Repulsionswechselwirkung auf; die Desorptionsenthalpien nehmen linear mit n ab. extrapoliert auf n 1 bis nahezu auf 0. – Eine eingehende Diskussion der im Bereich des Zweiphasengebietes auftretenden Hysterese fuhrt zu dem Schlus, das die Zersetzungsdrucke nahezu den Gleichgewichtsdrucken entsprechen. Aus ihrer Temperaturabhangigkeit ergaben sich die Zersetzungsenthalpien zu ΔHH2 = 9,32 ± 0,1; ΔHD2 = 8,88 ± 0,1 (kcal/mol), die Zersetzungsentropien zu ΔSH20 = 21,8 ± 0,2, ΔSD20 = 23,4 ± 0,2 (cal/grd.mol). Messungen an Pd-Mohr lieferten innerhalb der Fehlergrenzen dieselben Werte. - Fur die Trennfaktoren von H2/D2-Gemischen 1/1 an Pd-Mohr wurde α = 2,25 (50 °C) bis 3,7 (−78 °C) gefunden. By means of “transference catalysts”, for instance pulverized copper, UH3, or UD3, it is possible to measure H2 and D2 adsorption or desorption on bulk palladium (foil, wire) at normal and lower temperatures. This was done on Pd-sheet (0.3 and 0.15 mm) from + 75 to −78 °C; atomic ratios H/Pd and D/Pd were obtained up to n = 0.83. From the results in the α-phase region the chemical potentials of the dissolved gases are calculated for vanishing concentrations, their excess values being attributed to an attractive interaction. Contrary to this, the excess values calculated from the measurements in the β-phase region refer to repulsive interaction. The enthalpies of desorption decrease linearly with n, roughly down to zero if extrapolated to n 1. The hysteresis phenomena observed in the two-phase region are discussed in detail, it being concluded that the pressures of decomposition closely correspond to the equilibrium pressures. From the temperature dependence of these pressures measured in the two-phase region, enthalpies and entropies of decomposition are calculated: ΔHH2 = 9.32 ± 0.1 kcal/mole, ΔHD2 = 8.88 ± 0.1 kcal/mole, ΔSH20 = 21.8 ± 0.2 e.u., ΔSD20 = 23.4 ± 0.2 e.u. Measurements with palladium black, without use of transference catalysts, agree with those obtained on metal sheets. – For equimolar mixtures of H2 and D2, the separation factor is found to range from 2.25 at 50 °C to 3.7 at −78 °C.