Die neue H2A-Plattform — ein Netzwerk als Basis für Akzeptanz einer neuen Technologie

If hydrogen is to be promoted as a fuel of the future, established and tried-and-tested organisational structures and working methods must be complemented by flexible instruments capable of ensuring a maximum of innovation, productivity and information exchange with a wide range of players. The platform structure provides the ideal environment for sustainable development processes.     

Properties of autoclaved and thermally treated moulds made from γ-Ca2SiO4 and quartz at C/S ratios 0.5 to 1.5

From mixtures of γ-dicalcium silicate and quartz moulds were pressed and exposed to saturated steam (at 10, 15 and 20 atmospheres for 12, 24 and 48 hours). Under defined autoclaving conditions, by varying the C/S ratio, a more complete reaction between the starting components can be achieved, which results in better strenght properties of heated samples. The best compressive strengths (about 1900 kp/cm²) were exerted by moulds of composition C/S = 0.83, when they were autoclaved at 15 atmospheres for 48 hours. After heating at 1000°C, these moulds retained about 80% of their initial strength.     

Chloroplast Genome Annotation Tools: Prolegomena to the Identification of Inverted Repeats

The development of next-generation sequencing technology and the increasing amount of sequencing data have brought the bioinformatic tools used in genome assembly into focus. The final step of the process is genome annotation, which works on assembled genome sequences to identify the location of genome features. In the case of organelle genomes, specialized annotation tools are used to identify organelle genes and structural features. Numerous annotation tools target chloroplast sequences. Most chloroplast DNA genomes have a quadripartite structure caused by two copies of a large inverted repeat. We investigated the strategies of six annotation tools (Chloë, Chloroplot, GeSeq, ORG.Annotate, PGA, Plann) for identifying inverted repeats and analyzed their success using publicly available complete chloroplast sequences of taxa belonging to the asterid and rosid clades. The annotation tools use two different approaches to identify inverted repeats, using existing general search tools or implementing stand-alone solutions. The chloroplast sequences studied show that there are different types of imperfections in the assembled data and that each tool performs better on some sequences than the others.     

Rat Group IIA Secreted Phospholipase A2 Binds to Cytochrome c Oxidase and Inhibits Its Activity: A Possible Episode in the Development of Alzheimer’s Disease

Alzheimer’s disease (AD), a progressive form of dementia, is characterized by the increased expression of secreted phospholipase A₂ group IIA (GIIA) in the affected tissue and the dysfunction of neuronal mitochondria, similar to that induced by an orthologous GIIA from snake venom, β-neurotoxic ammodytoxin (Atx), in the motor neurons. To advance our knowledge about the role of GIIA in AD, we studied the effect of rat GIIA on the neuronal mitochondria and compared it with that of the Atx. We produced recombinant rat GIIA (rGIIA) and its enzymatically inactive mutant, rGIIA(D49S), and demonstrated that they interact with the subunit II of cytochrome c oxidase (CCOX-II) as Atx. rGIIA and rGIIA(D49S) bound to this essential constituent of the respiratory chain complex with an approximately 100-fold lower affinity than Atx; nevertheless, both rGIIA molecules potently inhibited the CCOX activity in the isolated rat mitochondria. Like Atx, rGIIA was able to reach the mitochondria in the PC12 cells from the extracellular space, independent of its enzymatic activity. Consistently, the inhibition of the CCOX activity in the intact PC12 cells and in the rat’s brain tissue sections was clearly demonstrated using rGIIA(D49S). Our results show that the effects of mammalian and snake venom β-neurotoxic GIIA on the neuronal mitochondria have similar molecular backgrounds. They suggest that the elevated extracellular concentration of GIIA in the AD tissue drives the translocation of this enzyme into local neurons and their mitochondria to inhibit the activity of the CCOX in the respiratory chain. Consequently, the process of oxidative phosphorylation in the neurons is attenuated, eventually leading to their degeneration. Atx was thus revealed as a valuable molecular tool for further investigations of the role of GIIA in AD.     

Improved modelling of the loading spectra using a mixture model approach

In order to perform a fatigue-life analysis of structures the parameters of the structure loading spectra must be assessed. If the load time series are counted using a two-parametric rainflow counting method, the structure loading spectrum provides a probability for the occurrence of a load-cycle with certain amplitude and mean values. It is beneficial for the prediction of the fatigue life to describe the loading spectrum by a continuous function. We have previously discovered that mixtures of Gaussian probability density functions can be used to model the loading spectra. The main problems of this approach that have not been satisfactorily resolved before are related to the estimation of the number of components in the applied mixture models, and to the modelling of the load-cycle distributions with relatively fat tails. In this article, we describe a method for estimating the parameters of mixture models, which allows automatic determination of the number of components in a mixture model. The presented method is applied for modelling simulated and measured loading spectra using mixtures of the multivariate Gaussian or t probability density functions. In the article we also show that the mixture of t probability density functions sometimes better describes the loading spectra than the mixture of Gaussian probability density functions.     

Transition from 1D to 2D Laser-Induced Ultrasonic Wave Propagation in an Extended Plate

Optodynamic interaction between a laser pulse and the surface of an opaque, solid elastic object produces transient waves that propagate and reverberate within the object. They can be, in general, categorized into three distinctive types which are all formed through different mechanisms: ablation-induced waves, light-pressure-induced waves, and thermoelastic waves. In this paper, out-of-plane displacements of such waves are simulated at the epicentral position on the opposite side of an extended plane-parallel elastic plate. Wave propagation is mathematically described by Green’s transfer functions convolved with suitable time profiles of the incoming laser pulses. The simulated size of the circularly symmetric laser-illuminated area on the plate surface is varied to show the limit-to-limit transition of the displacement waveforms: from a 2D point source to an infinite 1D source.     

Numerical and experimental analyses of a stirred vessel for a large volumetric flow rate of sparged air

Computational fluid dynamics (CFD) and experimental analyses of some of the basic characteristics of air sparging in a tall stirred vessel equipped with a three-stage impeller are presented. The impeller was assembled from a radial ABT impeller as the lower, a turbine 6PBT45 as the middle and an axial Scaba-type 3SHP1 impeller as the upper. All the impellers were of the same diameter, i.e., 225 mm, while the vessel diameter was 450 mm. The impeller's rotational speed was 178 r·min^-1. The aeration regime was established with an air volumetric flow rate of 28.3 m³·h^-1. To the best of our knowledge, this study is the first to consider the very high gassing rate by means of CFD in a tank stirred by three-stage axial/radial impellers. The numerical simulation was performed using the ANSYS Fluent (R17.2, 2016) code for solving the governing equations of fluid dynamics in single- and multi-phase systems. While discussing the bubble size distribution, a discrete population balance model (PBM) was used. Adopting CFD, the stirring power and the total void fraction (the total gas holdup) were calculated. The results were in good agreement with the measured values using a laboratory experimental device.