Objektivität und Macht : Das Genre "Schulbuch" als Hegemonieinstrument

Viele Studierende beginnen ihr geschichtswissenschaftliches Studium mit der Erwartung, durch den Einsatz der richtig gewählten Methode objektiv festzumachende Wahrheiten hinter Quellen erkennen und vermitteln zu können. Dass dies nicht der Fall ist, ist im akademischen Diskurs überwiegend akzeptiert. Die Erwartung an das wissenschaftliche Schreiben unterscheidet sich demnach maßgeblich zwischen dem akademischen Bereich und der breiteren Öffentlichkeit. Eine Ursache für diese Diskrepanz verorten wir, im Fall der Geschichtswissenschaft, in der Art und Weise, wie in der Schule Geschichte dargestellt wird. Schulbücher tragen als hegemoniales Instrument der Inhalts- und Wissensvermittlung dazu bei, Buchinhalte als gegebene Wahrheit zu akzeptieren. Es versteckt die komplexen wissenschaftlich-diskursiven Prozesse, die Wissen erzeugen. Wir unterscheiden daher das Genre "Schulbuch" von dem von uns definierten Genrecluster "wissenschaftlicher Text", wobei beide Objektivitäts- und Wahrheitsansprüche konträr behandeln. Durch eine Genrekritik zeigen wir, wie das Genre innerhalb seines institutionellen und ideologischen Kontextes seine Positionen reproduziert und sich selbst erhält

X20CoCrWMo10-9//Co3O4: a Metal-Ceramic Composite with Unique Efficiency Values for Water-Splitting in Neutral Regime

Water splitting allows the storage of solar energy into chemical bonds (H2+O2) and will help to implement the urgently needed replacement of limited available fossil fuels. Particularly in neutral environment electrochemically initiated water splitting suffers from low efficiency due to high overpotentials caused by the anode. Electro-activation of X20CoCrWMo10-9, a Co-based tool steel resulted in a new composite material (X20CoCrWMo10-9//Co3O4) that catalyzes the anode half-cell reaction of water electrolysis with a so far unequalled effectiveness. The current density achieved with this new anode in pH 7 corrected 0.1 M phosphate buffer is over a wide range of overpotentials around 10 times higher compared to recently developed, up-to-date electrocatalysts and represents the benchmark performance advanced catalysts show in regimes that support water splitting significantly better than pH 7 medium. X20CoCrWMo10-9//Co3O4 exhibited electrocatalytic properties not only at pH 7, but also at pH 13, which is much superior to the ones of IrO2-RuO2, single-phase Co3O4- or Fe/Ni- based catalysts. Both XPS and FT-IR experiments unmasked Co3O4 as the dominating compound on the surface of the X20CoCrWMo10-9//Co3O4 composite. Upon a comprehensive dual beam FIB-SEM (focused ion beam-scanning electron microscopy) study we could show that the new composite does not exhibit a classical substrate-layer structure due to the intrinsic formation of the Co-enriched outer zone. This structural particularity is basically responsible for the outstanding electrocatalytic OER performance

WNT signalling in prostate cancer

Genome sequencing and gene expression analyses of prostate tumours have highlighted the potential importance of genetic and epigenetic changes observed in WNT signalling pathway components in prostate tumours-particularly in the development of castration-resistant prostate cancer. WNT signalling is also important in the prostate tumour microenvironment, in which WNT proteins secreted by the tumour stroma promote resistance to therapy, and in prostate cancer stem or progenitor cells, in which WNT-β-catenin signals promote self-renewal or expansion. Preclinical studies have demonstrated the potential of inhibitors that target WNT receptor complexes at the cell membrane or that block the interaction of β-catenin with lymphoid enhancer-binding factor 1 and the androgen receptor, in preventing prostate cancer progression. Some WNT signalling inhibitors are in phase I trials, but they have yet to be tested in patients with prostate cancer

Monocytes, neutrophils, and platelets cooperate to initiate and propagate venous thrombosis in mice in vivo

Deep vein thrombosis (DVT) is a major cause of cardiovascular death. The sequence of events that promote DVT remains obscure, largely as a result of the lack of an appropriate rodent model. We describe a novel mouse model of DVT which reproduces a frequent trigger and resembles the time course, histological features, and clinical presentation of DVT in humans. We demonstrate by intravital two-photon and epifluorescence microscopy that blood monocytes and neutrophils crawling along and adhering to the venous endothelium provide the initiating stimulus for DVT development. Using conditional mutants and bone marrow chimeras, we show that intravascular activation of the extrinsic pathway of coagulation via tissue factor (TF) derived from myeloid leukocytes causes the extensive intraluminal fibrin formation characteristic of DVT. We demonstrate that thrombus-resident neutrophils are indispensable for subsequent DVT propagation by binding factor XII (FXII) and by supporting its activation through the release of neutrophil extracellular traps (NETs). Correspondingly, neutropenia, genetic ablation of FXII, or disintegration of NETs each confers protection against DVT amplification. Platelets associate with innate immune cells via glycoprotein Ibα and contribute to DVT progression by promoting leukocyte recruitment and stimulating neutrophil-dependent coagulation. Hence, we identified a cross talk between monocytes, neutrophils, and platelets responsible for the initiation and amplification of DVT and for inducing its unique clinical features

DMFC as Battery-Extender in solar-boat application

For special applications Direct Methanol Fuel Cells (DMFC) are close to commercial application or already commercialized today. However for the step from laboratory to a broader market of fuel cells, a significant cost reduction, as well as a lifetime and power density improvement of the systems is needed. The Goals of the BZ-BattExt Project should be reached by applying new knowledge in alternative materials, improved operation strategies and enhanced sub systems. In the project a 100 W DMFC compact system as battery extender was successfully developed and operated. The reduction of the number of components and the simplification of the system led to a high reduction in price, weight and volume. The feasibility of a micro-DMFC system was evaluated which enables a minimised system periphery due to an improved System Architecture. For this, alternative materials and functional components were developed and investigated leading to new membranes with reduced water and methanol permeation allowing a low air stoich operation and higher system efficiency. Gas diffusion layers of various compositions were tested and optimised materials were selected. New sealing materials with good methanol stability and optimized processibility in commercial production Processes were developed and the MEA preparation was adapted to the new materials. The use of a simple, cost-effective way of stack production was demonstrated for DMFC use. Using this new components and materials, coupled with the enhanced subsystem architectures and enhanced operation strategies, the build up and start-up of an improved micro DMFC System was achieved. The technical feasibility of the Results was investigated in the real application. The micro DMFC System was used as a battery range extender in a 6m solar boat. The DMFC fuel cell system serves as a basis for an efficient, compact and cost effective alternative for battery- or battery-extender systems and can fulfil a broad variety of applications

BZ-BattExt – DMFC as Battery-Extender in solar-boat application

For special applications Direct Methanol Fuel Cells (DMFC) are close to commercial application or already commercialized today. However for the step from laboratory to a broader market of fuel cells, a significant cost reduction, as well as an improvement in life time and power density of the systems is needed. These items were the focus of the project BZ-BattExt, to be reached by new knowledge in alternative materials, operation strategies as also the realisation of enhanced sub systems. This project is funded by the German Federal Ministry of Education and Research in the program of Micro fuel cells. In the project the feasibility of a micro-DMFC system is evaluated which enables a minimised system periphery due to an improved system architecture. For this, alternative materials and functional components were developed and investigated. New membranes with reduced water and methanol permeation allow operation at low air stoichiometry and favourable system efficiency. Gas diffusion layers of various compositions were tested and optimised material was selected. New sealing materials with good methanol stability and optimized processibility in commercial production process were developed. MEA preparation was adapted to the new materials. The use of a simple, cost-effective way of stack production was demonstrated for DMFC use. The investigation and construction of enhanced subsystems and operation strategies, which enable and optimise the use of new components and materials, as also the realisation of the micro-DMFC system is a focus of the project. The technical feasibility of the results is investigated in the application, which means it is tested as battery extender of a solar boat. The DMFC fuel cell system serves as a basis for an efficient, compact and cost effective alternative for battery- or battery-extender systems and can fulfil a broad variety of applications