1,4-Bis(4-nitrosophenyl)piperazine: novel bridging ligand in dinuclear complexes of rhodium(III) and iridium(III).

The synthesis, spectroscopic characterization and crystal structures of the first 1,4-bis(4-nitrosophenyl)piperazine (BNPP) (4) bridged dinuclear complexes of rhodium(III) and iridium(III) are presented. The reaction of the μ2-halogenido-bridged dimers [(η5-C5Me5)IrX2]2 [X = Cl (5a), Br (5b), I (5c)] and [(η5- C5Me5)RhCl2]2 (6a) with 4 yields the dinuclear complexes [(η5-C5Me5)IrX2]2-BNPP (7a–c) and [(η5-C5Me5)RhCl2]2-BNPP (8a). All new compounds were characterized by their NMR, IR and mass spectra. The X-ray structure analyses of the obtained half-sandwich complexes revealed a slightly distorted pseudo-octahedral configuration (“three-legged pianostool”) for the metal(III) centers. The bridging BNPP ligand is σ-N coordinated by both nitroso groups and shows different conformations of the piperazine ring depending on the solvent used for crystallization. Moreover the crystal structures of 1,4-bis(4-nitrosophenyl)piperazine (4) and its precursor 1,4-diphenylpiperazine (3) are reported

The Refined Swampland Distance Conjecture in Calabi-Yau Moduli Spaces

The Swampland Distance Conjecture claims that effective theories derived from a consistent theory of quantum gravity only have a finite range of validity. This will imply drastic consequences for string theory model building. The refined version of this conjecture says that this range is of the order of the naturally built in scale, namely the Planck scale. It is investigated whether the Refined Swampland Distance Conjecture is consistent with proper field distances arising in the well understood moduli spaces of Calabi-Yau compactification. Investigating in particular the non-geometric phases of Kahler moduli spaces of dimension $h^{11}\in\{1,2,101\}$, we always found proper field distances that are smaller than the Planck-length.Comment: 71 pages, 11 figures, v2: refs added, typos correcte

Abstract Natural Scenario Language Version 1.0

The development of modern driving assistant systems (assisted as well as automated) requires extensive testing and exact specification to ensure the quality of the developed systems. Therefore, scenarios are used throughout the whole process to act as accompanying artifact to assist within the design, implementation and testing procedures. Depending on the respective use case, different levels of abstraction, used natural languages and degrees of completeness are used for the scenarios. Due to the lack of an appropriate method for the specification of abstract scenarios that satisfies those needs for efficient usage, the language stiEF (acronym for “scenario-accompanied, text-based, iterative Evaluation of automated driving Functions”) was designed. This paper provides all details about the syntax and semantics of stiEF for the freeway domain. This enables the reader to read, understand, write and use stiEF for scenario descriptions

Bone substitute effect on vascularization and bone remodeling after application of phVEGF165 transfected BMSC

VEGF (vascular endothelial growth factor) promotes vascularization and remodeling of bone substitutes. The aim of this study was to examine the effect of distinct resorbable ceramic carriers on bone forming capacities of VEGF transfected bone marrow stromal cells (BMSC). A critical size defect of the radius in rabbits was filled either by a low surface scaffold called beta-TCP (tricalciumphsphate) or the high surface scaffold CDHA (calcium deficient hydroxy-apatite) loaded with autologous BMSC, which were either transfected with a control plasmid or a plasmid coding for phVEGF165. They were compared to unloaded scaffolds. Thus, six treatment groups (n = 6 in each group) were followed by X-ray over 16 weeks. After probe retrieval, the volume of new bone was measured by micro-CT scans and vascularization was assessed in histology. While only minor bone formation was found in both carriers when implanted alone, BMSC led to increased osteogenesis in both carriers. VEGF promoted vascularization of the scaffolds significantly in contrast to BMSC alone. Bone formation was increased in the beta-TCP group, whereas it was inhibited in the CDHA group that showed faster scaffold degradation. The results indicate that the interaction of VEGF transfected BMSC with resorbable ceramic carrier influences the ability to promote bone healing

Core-Collapse Supernovae: Reflections and Directions

Core-collapse supernovae are among the most fascinating phenomena in astrophysics and provide a formidable challenge for theoretical investigation. They mark the spectacular end of the lives of massive stars and, in an explosive eruption, release as much energy as the sun produces during its whole life. A better understanding of the astrophysical role of supernovae as birth sites of neutron stars, black holes, and heavy chemical elements, and more reliable predictions of the observable signals from stellar death events are tightly linked to the solution of the long-standing puzzle how collapsing stars achieve to explode. In this article our current knowledge of the processes that contribute to the success of the explosion mechanism are concisely reviewed. After a short overview of the sequence of stages of stellar core-collapse events, the general properties of the progenitor-dependent neutrino emission will be briefly described. Applying sophisticated neutrino transport in axisymmetric (2D) simulations with general relativity as well as in simulations with an approximate treatment of relativistic effects, we could find successful neutrino-driven explosions for a growing set of progenitor stars. First results of three-dimensional (3D) models have been obtained, and magnetohydrodynamic simulations demonstrate that strong initial magnetic fields in the pre-collapse core can foster the onset of neutrino-powered supernova explosions even in nonrotating stars. These results are discussed in the context of the present controversy about the value of 2D simulations for exploring the supernova mechanism in realistic 3D environments, and they are interpreted against the background of the current disagreement on the question whether the standing accretion shock instability (SASI) or neutrino-driven convection is the crucial agency that supports the onset of the explosion.Comment: 36 pages, 20 figures (43 eps files); submitted to Progress of Theoretical and Experimental Physics (PTEP

Analyse und Erzeugung von glatten Flächenübergängen für das CNC-Fräsen

In dieser Arbeit werden numerisch stabile Methoden zur Prüfung von Stetigkeiten an Flächenübergängen vorgestellt und Algorithmen zur Erzeugung von G^2-stetigen Flächenübergängen hergeleitet

Assessment of grassland biomass as second generation biofuel feedstock in Austria

Die vorliegende Arbeit untersuchte Szenarien für die Produktion von Biokraftstoffen der zweiten Generation aus Biomasse österreichischer Grünländer. Mittels schlüssiger Methodik wurden Input - Output Bilanzen sowie Output zu Input Raten von Kohlenstoff-, Treibhausgas- und Energieflüssen berechnet, die im Lebenszyklus der Biokraftstoffe auftraten. Um das Potential der Biokraftstoffe zu untersuchen, wurden insgesamt 27 Subsysteme verwendet die verschieden intensives Grünlandmanagement, drei Konversionstechnologien und unterschiedliche Modellhöfe beinhalteten. Wir setzten voraus, dass die Produktion von Biokraftstoffen aus Biomasse österreichischer Grünländer es ermöglichen würde Naturschutzanliegen (z.B. die Erhaltung von Biodiversität und landschaftlicher Diversität) mit einer Verringerung von Treibhausgasemissionen im Verkehrssektors zu verbinden, und dabei gleichzeitig erneuerbare Energie aus binnenländischen Ressourcen herzustellen.This study examined scenarios for the production of second generation biofuels from biomass of permanent grasslands in Austria. Using a coherent method, this study modelled the input-output balances and output/input ratios of carbon, GHG and energy fluxes during the biofuel life cycles. We used a range of scenarios (27 subsystems) to assess the potential of biofuels, including different grassland management intensities and biofuel conversion technologies for a range of model farms in Austria. We hypothesized that biofuel production from permanent grasslands in Austria would allow to address nature conservation issues (i.e., the conservation of biodiversity and landscape diversity) concurrently with strategies to mitigate greenhouse gas (GHG) emissions from the transport sector and provide a renewable energy supply from domestic sources