Non‐Metallic Inclusions in High‐Manganese‐Alloy Steels

The possibility of applying new high‐strength steels with excellent forming behaviour (TRIP, TWIP and LIP steels) in automotive manufacturing is a significant potential for improvement in the area of reducing weight while simultaneously increasing crash safety. The present work investigates endogenous inclusions in some high‐alloy TRIP and TWIP steels because the most stringent product requirements are tightly related to cleanness. The expected formation of inclusions is discussed based on thermodynamic observations made with ThermoCalc. The solidification conditions were varied in experiments with the so‐called SSCT (submerged split chill tensile) apparatus. Furthermore, different treatment times were set in order to investigate this influence on the inclusions. A catalogue of endogenous inclusions in these new steel grades is currently being created with the help of the automated SEM/EDX inclusion analysis system at voestalpine Stahl GmbH in Linz. Further studies will follow to systematically determine the interactions between steel, slag and refractory materials.     

Variants of Oxidized Regenerated Cellulose and Their Distinct Effects on Neuronal Tissue

Based on oxidized regenerated cellulose (ORC), several hemostyptic materials, such as Tabotamp^®, Equicel^® and Equitamp^®, have been developed to approach challenging hemostasis in neurosurgery. The present study compares ORC that differ in terms of compositions and properties, regarding their structure, solubility, pH values and effects on neuronal tissue. Cytotoxicity was detected via DNA-binding fluorescence dye in Schwann cells, astrocytes, and neuronal cells. Additionally, organotypic hippocampal slice cultures (OHSC) were analyzed, using propidium iodide, hematoxylin-eosin, and isolectin B₄ staining to investigate the cellular damage, cytoarchitecture, and microglia activation. Whereas Equicel^® led to a neutral pH, Tabotamp^® (pH 2.8) and Equitamp^® (pH 4.8) caused a significant reduction of pH (p < 0.001). Equicel^® and Tabotamp^® increased cytotoxicity significantly in several cell lines (p < 0.01). On OHSC, Tabotamp^® and Equicel^® led to a stronger and deeper damage to the neuronal tissue than Equitamp^® or gauze (p < 0.01). Equicel^® increased strongly the number of microglia cells after 24 h (p < 0.001). Microglia cells were not detectable after Tabotamp^® treatment, presumably due to an artifact caused by strong pH reduction. In summary, our data imply the use of Equicel^®, Tabotamp^® or Equitamp^® for specific applications in distinct clinical settings depending on their localization or tissue properties.     

Neue Erkenntnisse zum Verformungsverhalten des Frankfurter Tons

New knowledge about the deformation behaviour of Frankfurt clay und unloading conditions. Tishman and Speyer planed the construction of a new building complex “Opernturm” in the down town of Frankfurt, Germany. The construction of the new High‐Rise building required the demolishing of the old two high rise buildings of the Zurich insurance company. After demolishing the old high rise buildings, a time delay of about 6years has occurred. The deformations of the rest basement of the old buildings as well as the deformation of Neighbouring construction such as the underground tunnel were observed with time as a part of validating the serviceability requirements of the neighbouring constructions. The results of these measurements regarding the time effect on the behaviour of Frankfurt overconsolidated clay under unloading conditions will be presented. Furthermore, the results of cross hole tests that were carried out as a part of the design of the suggested piled raft foundation of the new high rise building to investigate the dynamic behaviour of Frankfurt subsoil will be demonstrated and discussed.     

Tyrosinase-glucose dehydrogenase substrate-recycling biosensor: A highly-sensitive measurement of phenolic compounds

Mushroom tyrosinase and glucose dehydrogenase from Acinetobacter calcoaceticus were immobilized in poly(vinyl)alcohol membranes and coupled with a Clark-type oxygen electrode to give a substrate (analyte) regenerating cycle for monitoring of nanomolar concentrations of phenolic compounds. In this way the response for catechol, phenol, p-cresol, p-chlorophenol and p-acetamidophenol was amplified by a factor of 450, 300, 240, 150, and 140, respectively. The resulting detection limit for catechol and phenol is 0·6 nmol dm⁻³ and 0·9 nmol dm⁻³, respectively. The measuring linear range for phenol obtained by the amplified electrode extends from 1 to 400 nmol dm⁻³. The comparison with the chemical (ascorbic acid) regeneration of the phenolic compounds demonstrates the efficiency of the enzymatic procedure. The biosensor can be used for monitoring of phenolic compounds in environmental or industrial samples.     

Nimodipine Exerts Time-Dependent Neuroprotective Effect after Excitotoxical Damage in Organotypic Slice Cultures

During injuries in the central nervous system, intrinsic protective processes become activated. However, cellular reactions, especially those of glia cells, are frequently unsatisfactory, and further exogenous protective mechanisms are necessary. Nimodipine, a lipophilic L-type calcium channel blocking agent is clinically used in the treatment of aneurysmal subarachnoid haemorrhage with neuroprotective effects in different models. Direct effects of nimodipine on neurons amongst others were observed in the hippocampus as well as its influence on both microglia and astrocytes. Earlier studies proposed that nimodipine protective actions occur not only via calcium channel-mediated vasodilatation but also via further time-dependent mechanisms. In this study, the effect of nimodipine application was investigated in different time frames on neuronal damage in excitotoxically lesioned organotypic hippocampal slice cultures. Nimodipine, but not nifedipine if pre-incubated for 4 h or co-applied with NMDA, was protective, indicating time dependency. Since blood vessels play no significant role in our model, intrinsic brain cell-dependent mechanisms seems to strongly be involved. We also examined the effect of nimodipine and nifedipine on microglia survival. Nimodipine seem to be a promising agent to reduce secondary damage and reduce excitotoxic damage.     

Generating Scenarios by Multi-Object Checking

These days, many systems are developed applying various UML notations to represent the structure and behavior of (technical) systems. In addition, for safety critical systems like Railway Interlocking Systems (RIS) the fulfillment of safety requirements is demanded. UML-based Railway Interlocking (UML-based RI) is proposed as a methodology in designing and developing RIS. It consists of infrastructure objects and UML is used to model the system behavior. This design is validated and demonstrated by using simulation with Rhapsody. Automated verification techniques like model checking have become a standard for proving the correctness of state-based systems. Unfortunately, one major problem of model checking is the state space explosion if too many objects have to be taken into account. Multi-object checking circumvents the state space explosion by checking one object at a time. We present an approach to enhance multi-object checking by generating counterexamples in a sequence diagram fashion providing scenarios for model-based testing.     

Reduction of synthetic stainless steel slags by aluminium

One of the most efficient ways to eliminate the harm of chromium oxide in stainless steel slag is to reduce chromium oxide in stainless steel slag using aluminium. In the present work, the Al reduction of synthetic CaO–SiO₂–Al₂O₃–MgO–Fe₂O₃–Cr₂O₃ stainless steelmaking slags at different conditions, including temperature, slag basicity and Al amount was investigated to get optimal conditions for the reduction and the metal–slag separation. It was found that the agglomeration of metal droplets and metal–slag separations were improved by increasing temperature. The reduction degrees of SiO₂, Fe₂O₃ and Cr₂O₃ were enhanced with increasing basicity of slag. The addition of CaF₂ in slag leads to better agglomerations of metal droplets and metal–slag separations. The highest reduction degree of chromium could reach 99% in slag with basicity of 2 at 1873 K.     

Fluorophore-Labeled Cyclic Nucleotides as Potent Agonists of Cyclic Nucleotide-Regulated Ion Channels

High-affinity fluorescent derivatives of cyclic adenosine and guanosine monophosphate are powerful tools for investigating their natural targets. Cyclic nucleotide-regulated ion channels belong to these targets and are vital for many signal transduction processes, such as vision and olfaction. The relation of ligand binding to activation gating is still challenging, and there is a need for fluorescent probes that enable the process to be broken down to the single-molecule level. This inspired us to prepare fluorophore-labeled cyclic nucleotides, which are composed of a bright dye and a nucleotide derivative with a thiophenol motif at position 8 that has already been shown to enable superior binding affinity. These bioconjugates were prepared by a novel cross-linking strategy that involves substitution of the nucleobase with a modified thiophenolate in good yield. Both fluorescent nucleotides are potent activators of different cyclic nucleotide-regulated ion channels with respect to the natural ligand and previously reported substances. Molecular docking of the probes excluding the fluorophore reveals that the high potency can be attributed to additional hydrophobic and cation-π interactions between the ligand and the protein. Moreover, the introduced substances have the potential to investigate related target proteins, such as cAMP- and cGMP-dependent protein kinases, exchange proteins directly activated by cAMP or phosphodiesterases.     

Capacity balancing for vanadium redox flow batteries through continuous and dynamic electrolyte overflow

Journal of Applied Electrochemistry - The vanadium crossover through the membrane can have a significant impact on the capacity of the vanadium redox flow battery (VFB) over long-term...