Toxicity of different wheat gliadins in coeliac disease

Summary To determine the toxic effect of different gliadins on coeliac patients, which has been variably assessed in the literature, wheat prolamines (gliadin) were separated into the main fractions-, -, -, and-gliadins by chromatography on Sulfopropyl Sephadex C-50. The chemical compositions of the gliands were characterized by polyacrylamide gel electrophoresis, amino-acid analysis, determination of amide nitrogen and peptide maps.The peptide fractions B2 and B3 were isolated from the gliadins by a peptic tryptic digestion, ultrafiltration and gel filtration on Sephadex G-50.The gliadins and the peptide fractions were examined for coeliac activity by immunological tests (LIF tests) and by organ-culture tests.The results show that the peptide fractions are generally more active than their respective gliadins. The peptide fractions of all gliadins have a coeliac-specific toxic effect; their activities correlate with the chemical composition of the gliadins.

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Untersuchungen von Gliadinfraktionen des Weizens auf Cöliakieaktivität

Zusammenfassung Zur Überprufung der teilweise widersprüchlichen Angaben in der Literatur über die cöliakieauslösende Wirkung einzelner Gliadinfraktionen wird Weizenprolamin (Gliadin) durch Ionenaustauschchromatographie an Sulfopropyl-Sephadex C-50 in die Hauptfraktionen-, -, - und-Gliadin aufgetrennt. Die Gliadine werden durch PAG-Elektrophorese, Aminosäureanalyse, Amid-N-Bestimmung und über die nach partieller enzymatischer Hydrolyse erhaltenen Peptidmuster in ihrer chemischen Zusammensetzung charakterisiert. Durch peptisch-tryptische Partialhydrolyse, Ultrafiltration und Gelchromatographie an Sephadex G-50 werden aus den einzelnen Gliadinen die Peptidfraktionen 132 und 133 gewonnen. Die Protein- und Peptidfraktionen werden in einem immunologischen Test (LIF-Test) bzw. in einem Organkultur-Test auf Cöliakieaktivität untersucht.Die Ergebnisse zeigen, daß die Peptidfraktionen durchweg größere Aktivität haben als die entsprechenden Proteine, und daß von den Peptidfraktionen aller Gliadine eine cöliakiespezifische Wirkung ausgeht, wobei die Aktivität mit der chemischen Zusammensetzung der Gliadine korreliert ist.

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Supported by a grant from Stiftung Volkswagenwerk     

A Noninformative Prior for Neural Networks

While many implementations of Bayesian neural networks use large, complex hierarchical priors, in much of modern Bayesian statistics, noninformative (flat) priors are very common. This paper introduces a noninformative prior for feed-forward neural networks, describing several theoretical and practical advantages of this approach. In particular, a simpler prior allows for a simpler Markov chain Monte Carlo algorithm. Details of MCMC implementation are included.     

Explaining Paradoxical Relations Between Academic Self-Concepts and Achievements: Cross-Cultural Generalizability of the Internal/External Frame of Reference Predictions Across 26 Countries.

The internal/external frame of reference (I/E) model explains a seemingly paradoxical pattern of relations between math and verbal self-concepts and corresponding measures of achievement, extends social comparison theory, and has important educational implications. In a cross-cultural study of nationally representative samples of 15-year-olds from 26 countries (total N = 55,577), I/E predictions were supported in that (a) math and verbal achievements were highly correlated, but math and verbal self-concepts were nearly uncorrelated; (b) math achievement had positive effects on math self-concept, but negative effects on verbal self-concept; and (c) verbal achievement had positive effects on verbal self-concept, but negative effects on math self-concept. Supporting the cross-cultural generalizability of predictions, multigroup structural equation models demonstrated good support for the generalizabilify of results across 26 countries participating in the Programme for International Student Assessment project sponsored by the Organisation for Economic Co-operation and Development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Demands on Attention and the Role of Response Priming in Visual Discrimination of Feature Conjunctions.

This study examined how response mapping of features within single- and multiple-feature targets affects decision-based processing and attentional capacity demands. Observers judged the presence or absence of 1 or 2 target features within an object either presented alone or with distractors. Judging the presence of 2 features relative to the less discriminable of these features alone was faster (conjunction benefits) when the task-relevant features differed in discriminability and were consistently mapped to responses. Conjunction benefits were attributed to asynchronous decision priming across attended, task-relevant dimensions. A failure to find conjunction benefits for disjunctive conjunctions was attributed to increased memory demands and variable feature-response mapping for 2- versus single-feature targets. Further, attentional demands were similar between single- and 2-feature targets when response mapping, memory demands, and discriminability of the task-relevant features were equated between targets. Implications of the findings for recent attention models are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A new method for in situ measurement of parameters and degradation processes in modern nanoscale programmable devices

This paper presents a new method and results from measurement of internal parameters of programmable nanoscale circuits, namely Xilinx FPGA devices and especially Zynq SoC devices designed on 28 nm TSMC’s technology and older 45 nm Spartan 6 device as well as Xilinx Virtex product lines. The method utilizes a new undersampling approach for frequency measurement and an easy way of processing BRAM data streams. The proposed flexible circuits have been used in various measurements of timing parameters and delays in FPGAs, including measurements or detection of the aging issues. The paper presents results of measurements under various core voltage values as performed on selected Xilinx FPGA platforms, including key results about limited usability of the latest 28 nm devices under accelerated conditions and possibility of studying or mitigating aging effects in FPGAs. The paper presents rare results of experiments, real measurements and data available from current as well as previous technology nodes and it attempts to uncover new facts and areas of the latest high-end technologies, including the area of aging and degradation processes in general. The new methodology, presented approach and results can also be used in various dependable systems, including selected aerospace, medical, automotive or transportation ones. It is also directly and easily applicable to modern processor and multicore systems.     

A new approach to network heterogeneity: Polymerization induced phase separation in photo-initiated,free-radical methacrylic systems

Non-reactive, thermoplastic prepolymers (poly- methyl, ethyl and butyl methacrylate) were added to a model homopolymer matrix composed of triethylene glycol dimethacrylate (TEGDMA) to form heterogeneous networks via polymerization induced phase separation (PIPS). PIPS creates networks with distinct phase structure that can partially compensate for volumetric shrinkage during polymerization through localized internal volume expansion. This investigation utilizes purely photo-initiated, free-radical systems, broadening the scope of applications for PIPS since these processing conditions have not been studied previously.The introduction of prepolymer into TEGDMA monomer resulted in stable, homogeneous monomer formulations, most of which underwent PIPS upon photo-irradiation, creating heterogeneous networks. During polymerization the presence of prepolymer enhanced autoacceleration, allowing for a more extensive ambient cure of the material. Phase separation, as characterized by dynamic changes in sample turbidity, was monitored simultaneously with monomer conversion and either preceded or was coincident with network gelation. Dynamic mechanical analysis shows a broadening of the tan delta peak and secondary peak formation, characteristic of phase-separated materials, indicating one phase rich in prepolymer and another depleted form upon phase separation. In certain cases, PIPS leads to an enhanced physical reduction of volumetric shrinkage, which is attractive for many applications including dental composite materials.     

Thermochemical Investigations in the System Cadmium-Praseodymium Relevant for Pyrometallurgical Fuel Reprocessing

Vapor pressure measurements, in terms of a (non-)isothermal isopiestic method, were carried out in the system Cd-Pr between 749 K and 1067 K (476 °C and 794 °C). Thermodynamic activities of cadmium as a function of temperature were obtained directly for the composition ranging from 50.0 to 85.7 at. pct Cd. From these results, partial molar enthalpies of mixing of Cd were derived for the corresponding composition range. The activity values of Cd were converted to an average sample temperature of 823 K (550 °C) by applying an integrated form of the Gibbs–Helmholtz equation. These data indicate that Cd₂Pr and Cd₅₈Pr₁₃ are probably the most stable intermetallic compounds in this system. Using an activity value of Pr from the literature as integration constant, Gibbs–Duhem integration was performed, and integral Gibbs energies are presented at 823 K (550 °C), referred to Cd(l) and α-Pr(s). Gibbs energies of formation at the stoichiometric compositions of the phases Cd₆Pr, Cd₅₈Pr₁₃, Cd₄₅Pr₁₁, Cd₃Pr, and Cd₂Pr were determined to be about ?18.8, ?23.5, ?24.8, ?28.7, and ?33.8 kJ g-atom^?1 at 823 K (550 °C), respectively.