Tunnel Magnetoresistance Sensors with Magnetostrictive Electrodes: Strain Sensors

Magnetostrictive tunnel magnetoresistance (TMR) sensors pose a bright perspective in micro- and nano-scale strain sensing technology. The behavior of TMR sensors under mechanical stress as well as their sensitivity to the applied stress depends on the magnetization configuration of magnetic tunnel junctions (MTJ)s with respect to the stress axis. Here, we propose a configuration resulting in an inverse effect on the tunnel resistance by tensile and compressive stresses. Numerical simulations, based on a modified Stoner–Wohlfarth (SW) model, are performed in order to understand the magnetization reversal of the sense layer and to find out the optimum bias magnetic field required for high strain sensitivity. At a bias field of -3.2 kA/m under a 0.2 × 10$^{-3}$ strain, gauge factors of 2294 and -311 are calculated under tensile and compressive stresses, respectively. Modeling results are investigated experimentally on a round junction with a diameter of 30 ± 0.2 μm using a four-point bending apparatus. The measured field and strain loops exhibit nearly the same trends as the calculated ones. Also, the gauge factors are in the same range. The junction exhibits gauge factors of 2150 ± 30 and -260 for tensile and compressive stresses, respectively, under a -3.2 kA/m bias magnetic field. The agreement of the experimental and modeling results approves the proposed configuration for high sensitivity and ability to detect both tensile and compressive stresses by a single TMR sensor

Diagnostik und Therapie von Lebermetastasen bei kolorektalem Primärtumor

Contrast-enhanced multislice computer tomography (MSCT) has established itself as the standard tomographic imaging method both for diagnosis and for treatment monitoring of hepatic lesions. To clarify local conditions before partial liver resection, diffusion-weighted magnetic resonance tomography (DWI-MRT) can also provide important additional information. In order to meet the criteria for a R0 resection, a margin of 0.5 mm seems to be sufficient. Neoadjuvant chemotherapy aiming to reduce tumour size can be given in parallel with portal artery embolisation without adversely affecting perioperative morbidity and mortality. As far as the management of primary resectable liver metastases is concerned, there is an urgent need for more studies. Despite the relatively limited evidence, adjuvant chemotherapy is currently more widely favoured in Germany than perioperative chemotherapy. There is also considerable need for studies concerning preoperative therapy in patients with liver metastases that are not (yet) resectable. In KRAS wild-type tumours, high response rates (in terms of a reduction in the size of metastases) are achieved with a cetuximab/chemotherapy combination. Bevacizumab/chemotherapy combinations lead to high rates of pathohistological complete and partial remissions. What the best parameter for judging the success of preoperative therapy is remains unknown, and so comparison studies using survival as a `hard' endpoint must be carried out

Coherently explaining UML statechart and collaboration diagrams by graph transformations

In this paper we continue our work on the formalization and validation of UML models by means of graph transformation systems. We here concentrate on statechart and collaboration diagrams albeit our approach covers use case, class, object, and sequence diagrams as well. The statechart and collaboration diagrams describe the operations of the underlying class diagram and include OCL expressions as guards and parts of message expressions. We illustrate in detail the generation of graph transformation rules for the statechart and collaboration diagrams

From UML Models to Graph Transformation Systems

In this paper we present an approach that allows to validate properties of UML models. The approach is based on an integrated semantics for central parts of the UML. We formally cover UML use case, class, object, statechart, collaboration, and sequence diagrams. Additionally full OCL is supported in the common UML fashion. Our semantics is based on the translation of a UML model into a graph transformation system consisting of graph transformation rules and a working graph that represents the system state. By applying the rules on the working graph, the evolution of the modeled system is simulated

Semantics of Visual Models in a Rule-based Setting

In this paper, some fundamental aspects of the semantics of rule-based systems are sketched and related to the semantics of visual models. A rule-based system comprises a set of rules and some control conditions including descriptions of initial and terminal configurations. Semantically, the rules specify a binary relation on configurations of some kind by means of rule applications which are restricted according to the control conditions. As visual models are usually represented by diagrams, graphs or similar configurations, the rule-based setting can be employed to provide visual models with semantics