Energy Metabolites as Biomarkers in Ischemic and Dilated Cardiomyopathy

With more than 25 million people affected, heart failure (HF) is a global threat. As energy production pathways are known to play a pivotal role in HF, we sought here to identify key metabolic changes in ischemic- and non-ischemic HF by using a multi-OMICS approach. Serum metabolites and mRNAseq and epigenetic DNA methylation profiles were analyzed from blood and left ventricular heart biopsy specimens of the same individuals. In total we collected serum from n = 82 patients with Dilated Cardiomyopathy (DCM) and n = 51 controls in the screening stage. We identified several metabolites involved in glycolysis and citric acid cycle to be elevated up to 5.7-fold in DCM (p = 1.7 × 10⁻⁶). Interestingly, cardiac mRNA and epigenetic changes of genes encoding rate-limiting enzymes of these pathways could also be found and validated in our second stage of metabolite assessment in n = 52 DCM, n = 39 ischemic HF and n = 57 controls. In conclusion, we identified a new set of metabolomic biomarkers for HF. We were able to identify underlying biological cascades that potentially represent suitable intervention targets.     

On the correspondence between abstract dialectical frameworks and nonmonotonic conditional logics

Annals of Mathematics and Artificial Intelligence - The exact relationship between formal argumentation and nonmonotonic logics is a research topic that keeps on eluding researchers despite recent...     

Efficiency Measures of Process Plans for Machined Parts

This paper presents an overview of the authors’ rooted tree technique for process planning. The overview provides the foundation for the main part of the paper, which explains how the rooted tree can be used to develop efficiency measures of process plans. The efficiency measures are determined by comparing an actual tree and its subgraphs with an "ideal" tree. The "ideal tree" is one that minimises the number of manufacturing operations. The paper proves that the "ideal tree" is a directed design dimension graph plus one operation. Three measures of efficiency are presented: finishing efficiency, preforming efficiency, and overall efficiency. The practical value of the efficiency measures is demonstrated by presenting measures of plans for four industrial parts. It is also argued that the efficiency measures provide a quantitative assessment of process plans that can be used to improve them and manufacturing technology.     

Entwurf aktiver RC-Filter mit nichtidealen Impedanzkonvertern

Übersicht Betrachtet wird der Entwurf aktiver RC-Filter, mit denen auch Dämpfungsforderungen, wie sie etwa die Trägerfrequenztechnik stellt, erfüllt werden können. Grundlage des Entwurfsverfahrens ist eine entsprechend bemessene LC-Kettenschaltung, die mit Hilfe von Impedanzkonvertern in eine aktive Schaltung umgesetzt wird. Die hierzu benötigten Konverter werden mit Operationsverstärkern aufgebaut. Untersucht werden die Einflüsse realer Operationsverstärker auf die Eigenschaften der mit ihnen realisierten Konverter. Es werden optimale Dimensionierungsbedingungen für diese nichtidealen Impedanzkonverter abgeleitet, sowie Möglichkeiten ihrer Einbeziehung in den Entwurf aktiver Filter erläutert. An einigen Beispielen werden die gewonnenen Ergebnisse auch experimentell belegt.

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Contents The design of active RC-filters, which can meet the requirements of FDM systems, is considered. These active filters are derived from conventionally designed LC-ladder networks by impedance converter embedding. Converter circuits are obtained using operational amplifiers. The influence of real amplifiers on the performance of the converters are studied. Optimum design equations for these nonideal impedance converters are derived. Possibilities for incorporating these converters in active filter design are considered. Examples will verify the results obtained also experimentally.

     

Review: geometric and dimensional tolerance modeling for sheet metal forming and integration with CAPP

The focus of this publication is a review of the state of the art in tolerance analysis, synthesis, and transfer for geometric and dimensional tolerances in sheet metal forming and the integration solutions with computer-aided process planning systems. In this context, the general tolerance methods are first described. Then, the mathematical models for sheet metal tolerance analysis and synthesis are examined in detail. To address the CAPP modeling concerns, the paper is then followed up with a brief review of past research works related to feature-based process planning. Finally, those imperative future research areas are identified.     

A new one-phase material model for the numerical prediction of critical material flow conditions in thixoforging processes

Thixoforging allows one-step forming processes of near-net shape components having excellent mechanical properties. However, the high sensitivity of thixoforging regarding process conditions requires precise modelling and determination of process related parameters. At the same time, simple numerical design proves challenging because of the inaccuracy of existing one-phase material models regarding the shear thinning flow behaviour of semi solid metals. Consequently, this paper deals with the development of a new one-phase material model providing a more precise simulation of materials’ shear rate dependency. By using this model, simulations could be performed, which allowed the prediction of solidification and flow-related component defects.     

Operation element-based efficiency for process plans and designs

In previous work the authors have developed graph-theoretic efficiency measures of process plans for rotational parts. The measures assess the technical efficiency under which a particular design can be manufactured, i.e. its manufacturability. This paper extends the earlier work by incorporating geometric dimensioning and tolerancing and developing a new technique for assessing the manufacturability of any part (prismatic and rotational). The aim is to develop an automated technique for assessing part designs.     

Tolerance transfer in sheet metal forming

A literature review of sheet metal forming errors as well as geometrical dimensions and tolerances (GD&T) shows that the theoretical means for the allocation of process tolerances with respect to GD&T are insufficient. In order to judge the influence of geometrical process errors (e.g., angular errors of bends), two typical sheet metal designs with parallelism and a position tolerance are studied. These case studies comprise a detailed analysis of tolerance chains including angular errors of bends and their positions. The resulting errors are compared with those resulting from length dimensional process errors and conclusions are drawn.     

Identification of the machine parameters in a vector-controlledinduction motor drive

High dynamic performance of pulse-width-modulated (PWM) inverter-fed induction motor drives was achieved by using the method of field-oriented control. This method requires the actual value of the rotor time constant as essential system information, based on how the magnitude and the position of the rotor flux are calculated. An online identification technique for the rotor time constant and for other machine parameters is described. The identification is based on an evaluation of the stator current trajectory, which is the dynamic response of the induction motor to the PWM-switching sequence. An analytical machine model is operated in parallel to the actual machine, having the stator voltages and the mechanical speed of the induction motor as input signals. The coincidence of the two stator current trajectories of the model and the machine serves as an error indicator for the parameter identification scheme, permitting repetitive updates of the model parameters     

Constraint-based and SAT-based diagnosis of automotive configuration problems

We compare the concepts and computation of optimized diagnoses in the context of Boolean constraint based knowledge systems of automotive configuration, namely the preferred minimal diagnosis and the minimum weighted diagnosis. In order to restore the consistency of an over-constrained system w.r.t. a strict total order of the user requirements, the preferred minimal diagnosis tries to keep the most preferred user requirements and can be computed, for example, by the FASTDIAG algorithm. In contrast, partial weighted MinUNSAT solvers aim to find a set of unsatisfied clauses with the minimum sum of weights, such that the diagnosis is of minimum weight. It turns out that both concepts have similarities, i.e., both deliver an optimal minimal correction subset. We show use cases from automotive configuration where optimized diagnoses are desired. We point out theoretical commonalities and prove the reducibility of both concepts to each other, i.e., both problems are FP^NP-complete, which was an open question. In addition to exact algorithms we present greedy algorithms. We evaluate the performance of exact and greedy algorithms on problem instances based on real automotive configuration data from three different German car manufacturers, and we compare the time and quality tradeoff.