389 research outputs found
Activation-independent platelet adhesion and aggregation under elevated shear stress
No full textPlatelet aggregation, which contributes to bleeding arrest and also to thrombovascular disorders, is thought to initiate after signaling-induced activation. We found that this paradigm does not apply under blood flow conditions comparable to those existing in stenotic coronary arteries. Platelets interacting with immobilized von Willebrand factor (VWF) aggregate independently of activation when soluble VWF is present and the shear rate exceeds 10 000 s-1 (shear stress = 400 dyn/cm2). Above this threshold, active A1 domains become exposed in soluble VWF multimers and can bind to glycoprotein Ibα, promoting additional platelet recruitment. Aggregates thus formed are unstable until the shear rate approaches 20 000 s-1 (shear stress = 800 dyn/cm.2). Above this threshold, adherent platelets at the interface of surface-immobilized and membrane-bound VWF are stretched into elongated structures and become the core of aggregates that can persist on the surface for minutes. When isolated dimeric A1 domain is present instead of native VWF multimers, activation-independent platelet aggregation occurs without requiring shear stress above a threshold level, but aggregates never become firmly attached to the surface and progressively disaggregate as shear rate exceeds 6000 s-1. Platelet and VWF modulation by hydrodynamic force is a mechanism for activation-independent aggregation that may support thrombotic arterial occlusion
Reininger, Robert, Dr. Privatdozent an der Universität Wien. Philosophie des Erkennens. Ein Beitrag zur Geschichte und Fortbildung des Erkenntnisproblems.
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Supplementary materials to: Psychotherapeutische gruppenbezogene Identifikationen, Vertiefungsverfahrenszugehörigkeit und Einstellungen zur Reform der Psychotherapeut*innenausbildung
No full textSupplementary materials for: Reininger, K. M., Biel, H. M., Zapf, H., Krott, N. R., Hennig, T., Moritz, S., Löew, B., Jungclaussen, I., & Algner-Herzmann, D. (2021). Psychotherapeutische gruppenbezogene Identifikationen, Vertiefungsverfahrenszugehörigkeit und Einstellungen zur Reform der Psychotherapeut: innenausbildung. PDP-Psychodynamische Psychotherapie, 20(2), 167-181. https://doi.org/10.21706/pdp-20-2-167Im Kontext politisierter Auseinandersetzungen um die 2019/2020 verabschiedete Ausbildungsreform untersuchen wir im vorliegenden Beitrag eine Stichprobe von 323 Psychotherapeut:innen (approbiert oder in Ausbildung) hinsichtlich ihrer Erwartungen zur Reform sowie ihren gruppenbezogenen super- und supraordinaten psychotherapeutischen Identifikationen. Wir beobachten, dass die Obergruppe psychoanalytisch begründet Tätiger (das heißt sich als tiefenpsychologisch fundiert, psychoanalytisch oder psychodynamisch Identifizierende) im Vergleich zu Verhaltenstherapeut:innen (1) negativere Einstellungen zur Reform, (2) weniger übergeordnete, mit allen Psychotherapeut:innen geteilte und (3) mehr untergeordnete, nur von der Gruppe des eigenen Vertiefungsverfahrens geteilte Identifikationen aufweisen. Innerhalb der psychoanalytisch begründet Tätigen lässt sich ein ähnliches Muster beobachten: Die Tiefenpsycholog:innen weisen tendenziell (1) optimistischere Erwartungen hinsichtlich der Reform und (2) mehr übergeordnete, gemeinsam geteilte Identifikationen mit der Gesamtgruppe aller Psychotherapeut:innen auf als sich als Psychoanalytiker:innen oder als Psychodynamiker:innen Identifizierende. Wir diskutieren die Bedeutungen und Implikationen der Ergebnisse
Interest Rate Pass-Through in Central and Eastern Europe: Reborn from Ashes Merely to Pass Away?
No full textIn this study, we seek to better understand the interest rate pass-through in five Central and Eastern European countries – the Czech Republic, Hungary, Poland, Slovakia and Slovenia, the CEE-5. Our pass-through estimates for several retail rates are generally lower than those reported in the literature, given the absence of cointegration between policy rates and long- or even short-term market rates. In addition, the pass-through has been declining over time in the CEE-5, and we argue that it is likely to decrease further in the future. Finally, the pass-through appears similar in the CEE-5 than in Spain and is higher than in core euro area countries. Hence, euro adoption by the CEE-5 would not further increase heterogeneity within the euro area with regard to the interest rate passthrough. However, substantially more research is needed to establish commonalities and differences between the CEE-5 and the euro area with respect to the reaction of prices and output to monetary policy action.interest rate pass-through, monetary transmission mechanism, transition economies, Central and Eastern Europe, Austria, Germany, Spain.
The Plasmodium falciparum, Nima-related kinase Pfnek-4: a marker for asexual parasites committed to sexual differentiation
No full text<b>Background</b>
Malaria parasites undergo, in the vertebrate host, a developmental switch from asexual replication to sexual differentiation leading to the formation of gametocytes, the only form able to survive in the mosquito vector. Regulation of the onset of the sexual phase remains largely unknown and represents an important gap in the understanding of the parasite's complex biology.
<b>Methods:</b>
The expression and function of the Nima-related kinase Pfnek-4 during the early sexual development of the human malaria parasite Plasmodium falciparum were investigated, using three types of transgenic Plasmodium falciparum 3D7 lines: (i) episomally expressing a Pfnek-4-GFP fusion protein under the control of its cognate pfnek-4 promoter; (ii) episomally expressing negative or positive selectable markers, yeast cytosine deaminase-uridyl phosphoribosyl transferase, or human dihydrofolate reductase, under the control of the pfnek-4 promoter; and (iii) lacking a functional pfnek-4 gene. Parasite transfectants were analysed by fluorescence microscopy and flow cytometry. In vitro growth rate and gametocyte formation were determined by Giemsa-stained blood smears.
<b>Results:</b>
The Pfnek-4-GFP protein was found to be expressed in stage II to V gametocytes and, unexpectedly, in a subset of asexual-stage parasites undergoing schizogony. Culture conditions stimulating gametocyte formation resulted in significant increase of this schizont subpopulation. Moreover, sorted asexual parasites expressing the Pfnek-4-GFP protein displayed elevated gametocyte formation when returned to in vitro culture in presence of fresh red blood cells, when compared to GFP- parasites from the same initial population. Negative selection of asexual parasites expressing pfnek-4 showed a marginal reduction in growth rate, whereas positive selection caused a marked reduction in parasitaemia, but was not sufficient to completely abolish proliferation. Pfnek-4- clones are not affected in their asexual growth and produced normal numbers of stage V gametocytes.
<b>Conclusions:</b>
The results indicate that Pfnek-4 is not strictly gametocyte-specific, and is expressed in a small subset of asexual parasites displaying high rate conversion to sexual development. Pfnek-4 is not required for erythrocytic schizogony and gametocytogenesis. This is the first study to report the use of a molecular marker for the sorting of sexually-committed schizont stage P. falciparum parasites, which opens the way to molecular characterization of this pre-differentiated subpopulation
Microfocusing at the PG1 beamline at FLASH
No full textThe Kirkpatrick-Baez (KB) refocusing mirror system installed at the PG1 branch of the plane-grating monochromator beamline at the soft X-ray/XUV free-electron laser in Hamburg (FLASH) is designed to provide tight aberration-free focusing down to 4 µm × 6 µm full width at half-maximum (FWHM) on the sample. Such a focal spot size is mandatory to achieve ultimate resolution and to guarantee best performance of the vacuum-ultraviolet (VUV) off-axis parabolic double-monochromator Raman spectrometer permanently installed at the PG1 beamline as an experimental end-station. The vertical beam size on the sample of the Raman spectrometer, which operates without entrance slit, defines and limits the energy resolution of the instrument which has an unprecedented design value of 2 meV for photon energies below 70 eV and about 15 meV for higher energies up to 200 eV. In order to reach the designed focal spot size of 4 µm FWHM (vertically) and to hold the highest spectrometer resolution, special fully motorized in-vacuum manipulators for the KB mirror holders have been developed and the optics have been aligned employing wavefront-sensing techniques as well as ablative imprints analysis. Aberrations like astigmatism were minimized. In this article the design and layout of the KB mirror manipulators, the alignment procedure as well as microfocus optimization results are presented
Reininger, Robert (28.09.1869-17.06.1955; Philosophie); 1936
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Unterschrift: RReininger
http://scopeq.cc.univie.ac.at/Query/detail.aspx?id=3675
A NIMA-related protein kinase is essential for completion of the sexual cycle of malaria parasites
No full textThe molecular mechanisms regulating the sexual development of malaria parasites from gametocytes to oocysts in their mosquito vector are still largely unexplored. In other eukaryotes, NIMA-related kinases (Neks) regulate cell cycle progression and have been implicated in the regulation of meiosis. Here, we demonstrate that Nek-4, a new Plasmodium member of the Nek family, is essential for completion of the sexual cycle of the parasite. Recombinant Plasmodium falciparum Nek-4 possesses protein kinase activity and displays substrate preferences similar to those of other Neks. Nek-4 is highly expressed in gametocytes, yet disruption of the nek-4 gene in the rodent malaria parasite P. berghei has no effect on gamete formation and subsequent fertilization. However, further differentiation of zygotes into ookinetes is abolished. Measurements of nuclear DNA content indicate that zygotes lacking Nek-4 fail to undergo the genome replication to the tetraploid level that precedes meiosis. Cell cycle progression in the zygote is identified as a likely precondition for its morphological transition to the ookinete and for the successful establishment of a malaria infection in the mosquito.INSERM-EPF
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