Organverteilungssysteme im Transplantationswesen aus ökonomischer Sicht

Zusammenfassung.   Auch nach dem Beschlu? des Gesetzgebers zugunsten einer sogenannten Informationsl?sung bleibt das Problem angemessener Vergabekriterien für die vorhandenen Organe, da diese Frage im neuen Organspendegesetz nicht abschlie?end gekl?rt ist. In dem Beitrag werden verschiedene Allokationsverfahren bezüglich ihrer gesellschaftlichen Akzeptanz und ?konomischen Effizienz beurteilt. Dazu werden medizinische Kriterien (z.B. HLA-Kompatibilt?t) und nicht-medizinsche Kriterien (z.B. Zahlungsbereitschaft des Spenders oder Zufall) anhand verschiedener allgemein akzeptierter Zielsetzungen (z.B. gleicher Zugang zu Gesundheitsleistungen oder geringe Kosten) abgewogen. Als innovative Form eines Organgewinnungssystemes wird die Clubl?sung vorgestellt, die den Spendern erlaubt, Pr?ferenzen bei der Verwendung der Organe zu realisieren. Scoringsysteme k?nnen darüber hinaus helfen, die Transparenz der Organverteilung zu erh?hen. Aus ?konomischer Sicht sind dabei vor allem medizinische Kriterien relativ zu nicht-medizinischen Merkmalen st?rker zu gewichten.      

MiniBrass: Soft constraints for MiniZinc

Over-constrained problems are ubiquitous in real-world decision and optimization problems. Plenty of modeling formalisms for various problem domains involving soft constraints have been proposed, such as weighted, fuzzy, or probabilistic constraints. All of them were shown to be instances of algebraic structures. In terms of modeling languages, however, the field of soft constraints lags behind the state of the art in classical constraint optimization. We introduce MiniBrass, a versatile soft constraint modeling language building on the unifying algebraic framework of partially ordered valuation structures (PVS) that is implemented as an extension of MiniZinc and MiniSearch. We first demonstrate the adequacy of PVS to naturally augment partial orders with a combination operation as used in soft constraints. Moreover, we provide the most general construction of a c-semiring from an arbitrary PVS. Both arguments draw upon elements from category theory. MiniBrass turns these theoretical considerations into practice: It offers a generic extensible PVS type system, reusable implementations of specific soft constraint formalisms as PVS types, operators for complex PVS products, and morphisms to transform PVS. MiniBrass models are compiled into MiniZinc to benefit from the wide range of solvers supporting FlatZinc. We evaluated MiniBrass on 28 “softened” MiniZinc benchmark problems with six different solvers. The results demonstrate the feasibility of our approach.     

Automated classification of content components in technical communication

Automated classification is usually not adjusted to specialized domains due to a lack of suitable data collections and insufficient characterization of the domain‐specific content and its effect on the classification process. This work describes an approach for the automated multiclass classification of content components used in technical communication based on a vector space model. We show that differences in the form and substance of content components require an adaption of document‐based classification methods and validate our assumptions with multiple real‐world data sets in 2 languages. As a result, we propose general adaptions on feature selection and token weighting, as well as new ideas for the measurement of classifier confidence and the semantic weighting of XML‐based training data. We introduce several potential applications of our method and provide prototypical implementation. Our contribution beyond the state of the art is a dedicated procedure model for the automated classification of content components in technical communication, which outperforms current document‐centered or domain‐agnostic approaches.     

Insights into the In Vitro Formation of Apatite from Mg-Stabilized Amorphous Calcium Carbonate

A protein-free formation of bone-like apatite from amorphous precursors through ball-milling is reported. Mg²⁺ ions are crucial to achieve full amorphization of CaCO₃. Mg²⁺ incorporation generates defects which strongly retard a recrystallization of ball-milled Mg-doped amorphous calcium carbonate (BM-aMCC), which promotes the growth of osteoblastic and endothelial cells in simulated body fluid and has no effect on endothelial cell gene expression. Ex situ snapshots of the processes revealed the reaction mechanisms. For low Mg contents (<30%) a two phase system consisting of Mg-doped amorphous calcium carbonate (ACC) and calcite “impurities” was formed. For high (>40%) Mg²⁺ contents, BM-aMCC follows a different crystallization path via magnesian calcite and monohydrocalcite to aragonite. While pure ACC crystallizes rapidly to calcite in aqueous media, Mg-doped ACC forms in the presence of phosphate ions bone-like hydroxycarbonate apatite (dahllite), a carbonate apatite with carbonate substitution in both type A (OH⁻) and type B (PO₄³⁻) sites, which grows on calcite “impurities” via heterogeneous nucleation. This process produces an endotoxin-free material and makes BM-aMCC an excellent “ion storage buffer” that promotes cell growth by stimulating cell viability and metabolism with promising applications in the treatment of bone defects and bone degenerative diseases.     

Encoding Information on the Excited State of a Molecular Spin Chain

The quantum states of nano-objects can drive electrical transport properties across lateral and local-probe junctions. This raises the prospect, in a solid-state device, of electrically encoding information at the quantum level using spin-flip excitations between electron spins. However, this electronic state has no defined magnetic orientation and is short-lived. Using a novel vertical nanojunction process, these limitations are overcome and this steady-state capability is experimentally demonstrated in solid-state spintronic devices. The excited quantum state of a spin chain formed by Co phthalocyanine molecules coupled to a ferromagnetic electrode constitutes a distinct magnetic unit endowed with a coercive field. This generates a specific steady-state magnetoresistance trace that is tied to the spin-flip conductance channel, and is opposite in sign to the ground state magnetoresistance term, as expected from spin excitation transition rules. The experimental 5.9 meV thermal energy barrier between the ground and excited spin states is confirmed by density functional theory, in line with macrospin phenomenological modeling of magnetotransport results. This low-voltage control over a spin chain's quantum state and spintronic contribution lay a path for transmitting spin wave-encoded information across molecular layers in devices. It should also stimulate quantum prospects for the antiferromagnetic spintronics and oxides electronics communities.     

Printing Reconfigurable Bundles of Dielectric Elastomer Fibers

Active soft materials that change shape on demand are of interest for a myriad of applications, including soft robotics, biomedical devices, and adaptive systems. Despite recent advances, the ability to rapidly design and fabricate active matter in complex, reconfigurable layouts remains challenging. Here, the 3D printing of core-sheath-shell dielectric elastomer fibers (DEF) and fiber bundles with programmable actuation is reported. Complex shape morphing responses are achieved by printing individually addressable fibers within 3D architectures, including vertical coils and fiber bundles. These DEF devices exhibit resonance frequencies up to 700 Hz and lifetimes exceeding 2.6 million cycles. The multimaterial, multicore-shell 3D printing method opens new avenues for creating active soft matter with fast programable actuation.     

Segregation of Pt and Re During CO2 Reforming of CH4

Pt–Re supported on Ce_0.52 Zr_0.48 O₂ was studied for the carbon dioxide reforming of methane at 800 °C. Diffuse reflectance fourier transform infrared spectroscopy and temperature programmed reduction studies suggest that Pt and Re segregation occurs during the reaction. The segregation results in an increase in the Pt sites available for CH₄ decomposition and results in the bimetallic catalyst exhibiting an increase in the conversion of methane with time on stream. After 20 h of reaction, the CH₄ conversion observed for the bimetallic catalyst was the same as the CH₄ conversion observed for the monometallic catalyst.     

Feststoffbildung durch Kristallisation und Fällung

Formation of solids by crystallization and precipitation. Formation of solids from solutions can take place by crystallization or precipitation. The principal factor is the relationship between solubility and supersaturation. In crystallization, the solubility of the crystallising substance is so high that the formation of solids occurs largely in the metastable zone in the immediate vicinity of the solubility limits. Crystal growth and nucleation are functions of supersaturation. If a high supersaturation is required at low substance-specific growth rates for an adequate crystal growth, high nucleation rates and hence small crystals will result. On this basis, the authors present information for the specific design of crystallization processes. In contrast, the solubility of the precipitated product must be very low for precipitation. Direct crystal formation is possible only for substance systems of high solubility. As a rule, however, the precipitated substance is so insoluble that solids are formed via amorphous intermediates. The results of a large number of experiments show the influence of various parameters of the precipitation process on the filtrability of the precipitated product.