On the Reaction of Nitrilium Salts with Heterocyclic Nitrones

Nitrilium hexachloroantimonates 1a – c react with pyridine N-oxides 2a , d , f , j , m , o to afford bicyclic 2,3-dihydropyridinium salts 5a – p . The constitution of 5f was secured by an X-ray crystallographic analysis. Compounds 5 proved to be thermally labile (23–82°C) rearranging to 2-acylamino- pyridinium salts 6a , f – i or decomposing to tars. The benzimidazole-3-oxide 7 reacts with nitrilium salts 1a , b to 2-acylaminobenzimidazoles 9a , b . The experimental results as well as AM1 calculations support a mechanism for the reaction of nitrilium cations with heterocyclic nitrones, which has originally been suggested by Abramovitch [25, 26].     

The semantic Web in one day

To gain momentum, technologies for building private semantic Webs or parts of the World Wide semantic Web must become a commodity and easy to integrate. To determine just how far semantic Web technologies have come, we wanted to create a snapshot of what you could do by applying and assembling existing semantic Web technologies - in one day.     

Computational Complexity and Anytime Algorithm for Inconsistency Measurement

Measuring inconsistency degrees of inconsistent knowledge bases is an important problem as it provides context information for facilitating inconsistency handling. Many methods have been proposed to solve this problem and a main class of them is based on some kind of paraconsistent semantics. In this paper, we consider the computational aspects of inconsistency degrees of propositional knowledge bases under 4-valued semantics. We ˉrst give a complete analysis of the computational complexity of computing inconsistency degrees. As it turns out that computing the exact inconsistency degree is intractable, we then propose an anytime algorithm that provides tractable approximations of the inconsistency degree from above and below. We show that our algorithm satisˉes some desirable properties and give experimental results of our implementation of the algorithm.     

Periapical status, quality of root canal fillings and estimated endodontic treatment needs in an urban German population

A child was operated 3 times because of a recurrent growth hormone- and prolactin-producing pituitary adenoma. Between the operations she was treated for five years with bromocriptine. The characteristics of the tumour cell population collected after the last operation was now examined by electron microscopy, immunocytochemistry, and in tissue culture and compared to those of the primary tumour cells reported earlier. A prominent change was the reversal of the proportion of the densely and sparsely granulated cells in favour of the GH-type, densely granulated cells. These cells, some of them coexpressing PRL, did not essentially change their characteristics either in vivo or in culture. On the other hand, pleomorphous cells with smaller cytoplasmic area and prominent lysosomal structures represented the sparsely granulated population containing PRL or both PRL and GH. The morphological alteration of the PRL-type cells was also reflected in vitro. Hence, while GH-type cells prevail, at least a sub-population of PRL-type cells survives long-term bromocriptine administration. A shift in the incidence of the two cell types in favour of the GH-type cells explains the change in the endocrine status of the patient.     

Additive manufacturing of AlSi10Mg samples using the selective laser melting technique: correlation between tensile and torsion behaviour

Additive manufacturing offers unique possibilities to produce complex components, which would not be possible or only very difficult to be realizable with conventional manufacturing processes. The potential of additive manufacturing of aluminum alloys has already been realized in prototyping, but still offers potential in the establishment of series applications. For enabling the establishment of additive manufacturing in series applications, comprehensive knowledge about the material behavior is necessary. This study examines the torsional behavior of additive manufactured AlSi10Mg samples and shows the correlation between tensile and torsional strength. Comprehensive torsion tests with strain gauges were performed and significant directional dependencies were shown. The correlation factor in the area of torsional yield strength/tensile yield strength and torsional strength/tensile strength was determined and was compared with the yield/failure conditions according to Tresca and von Mises.     

DOLCE ergo SUMO: On foundational and domain models in the SmartWeb Integrated Ontology (SWIntO)

Increased availability of mobile computing, such as personal digital assistants (PDAs), creates the potential for constant and intelligent access to up-to-date, integrated and detailed information from the Web, regardless of one's actual geographical position. Intelligent question-answering requires the representation of knowledge from various domains, such as the navigational and discourse context of the user, potential user questions, the information provided by Web services and so on, for example in the form of ontologies. Within the context of the SmartWeb project, we have developed a number of domain-specific ontologies that are relevant for mobile and intelligent user interfaces to open-domain question-answering and information services on the Web. To integrate the various domain-specific ontologies, we have developed a foundational ontology, the SmartSUMO ontology, on the basis of the DOLCE and SUMO ontologies. This allows us to combine all the developed ontologies into a single SmartWeb Integrated Ontology (SWIntO) having a common modeling basis with conceptual clarity and the provision of ontology design patterns for modeling consistency. In this paper, we present SWIntO, describe the design choices we made in its construction, illustrate the use of the ontology through a number of applications, and discuss some of the lessons learned from our experiences.     

Extracting reduced logic programs from artificial neural networks

Artificial neural networks can be trained to perform excellently in many application areas. Whilst they can learn from raw data to solve sophisticated recognition and analysis problems, the acquired knowledge remains hidden within the network architecture and is not readily accessible for analysis or further use: Trained networks are black boxes. Recent research efforts therefore investigate the possibility to extract symbolic knowledge from trained networks, in order to analyze, validate, and reuse the structural insights gained implicitly during the training process. In this paper, we will study how knowledge in form of propositional logic programs can be obtained in such a way that the programs are as simple as possible—where simple is being understood in some clearly defined and meaningful way.     

Neues aus der Chemie der Iminiumsalze

Recent Developments in Iminium Salt Chemistry Iminium salts are of continuing interest as versatile building blocks in organic synthesis. This progress report from different laboratories highlights some current research activities in iminium salt chemistry. Several contributions focus on novel synthetic applications of isolable, functionalized iminium systems such as α,β-unsaturated iminium salts (e.g. vinamidinium, 3-trifloxy, 3-chloro-, 3-isocyanato- and 3-thiopropene iminium, as well as propyne iminium salts), furthermore on phosgene iminium chloride and trifluoromethyl-substituted iminium salts. Iminium intermediates occur in various synthetic transformations; for example, cyclopropane iminium ions are intermediates in nucleophilic substitution reactions at bicyclic aminocyclopropanes. Also reported is the synthesis of a variety of novel orthoamides and their use as synthetic building blocks. Research directed to the application of vinamidinium salts in materials science is also presented.     

Relationship between Phase Fractions and Mechanical Properties in Heat-Treated Laser Powder-Bed Fused Co-Based Dental Alloys

Metal additive manufacturing of dental prostheses consisting of cobalt−chromium−tungsten (Co−Cr−W) alloys poses an alternative to investment casting. However, metal additive manufacturing processes like Laser Powder-Bed Fusion (LPBF) can impact the elastic constants and the mechanical anisotropy of the resulting material. To investigate the phase compositions of mechanically different specimens in dependence of their postprocessing steps (e. g. heat treatment to relieve stress), the current study uses X-ray Diffraction (XRD), Electron BackScatter Diffraction (EBSD), and Transmission Electron Microscopy (TEM) for phase identification. Our studies connect plastic deformation of Remanium star CL alloy with the formation of the hexagonal ϵ-phase and heat treatment with the formation of the D024-phase, while partially explaining previously observed differences in Young's moduli.