Technical UniversityMunchen

Garching bei München, Germany

Technical UniversityMunchen

Garching bei München, Germany
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Nasluzov V.A.,Siberian Federal University | Shulimovich T.V.,RAS Institute of Chemistry and Chemical Technology | Shor A.M.,RAS Institute of Chemistry and Chemical Technology | Bukhtiyarov V.I.,RAS Boreskov Institute of Catalysis | Rosch N.,Technical UniversityMunchen
Physica Status Solidi (B) Basic Research | Year: 2010

We calculated the structures of and analyzed the bonding in adsorption complexes of small gold species Aun on α-Al2O3(0001), n = 1-6, and γ-Al2O3(001), n = 1-5. We applied a scalar-relativistic gradient-corrected density functional (DF) method to cluster models of the support that were embedded in an extended elastic polarizable environment (EPE). The shortest Au-O distances, 204-211 pm, are consistent with extended X-ray adsorption fine structure (EXAFS) data for gold clusters on alumina surfaces. The calculated total adsorption energies increase with cluster nuclearity, up to n=4, but drop for larger adsorbed species. In the gas phase, these small gold clusters exhibit a planar structure which they keep, oriented parallel to the surface, as adsorbates on α-Al2O3(0001). Unfavorable energy contributions result for larger clusters as their planar shape is notably distorted by the interaction with the support which amounts to 0.5-1.5 eV. On γ-Al2O3(001), also the larger gold clusters retain their intrinsic planar structure as they adsorb oriented perpendicular to the surface. The corresponding adsorption energies are slightly smaller, 0.3-1.2 eV. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hoffmann A.,University of Virginia | Bredno J.,Philips | Wendland M.F.,Neuroradiology Section | Derugin N.,University of California at San Francisco | And 6 more authors.
Stroke | Year: 2011

Background and Purpose- We sought to validate the blood-brain barrier permeability measurements extracted from perfusion-weighted MRI through a relatively simple and frequently applied model, the Patlak model, by comparison with gold standard histology in a rat model of ischemic stroke. Methods- Eleven spontaneously hypertensive rats and 11 Wistar rats with unilateral 2-hour filament occlusion of the right middle cerebral artery underwent imaging during occlusion at 4 hours and 24 hours after reperfusion. Blood-brain barrier permeability was imaged by gradient echo imaging after the first pass of the contrast agent bolus and quantified by a Patlak analysis. Blood-brain barrier permeability was shown on histology by the extravasation of Evans blue on fluorescence microscopy sections matching location and orientation of MR images. Cresyl-violet staining was used to detect and characterize hemorrhage. Landmark-based elastic image registration allowed a region-by-region comparison of permeability imaging at 24 hours with Evans blue extravasation and hemorrhage as detected on histological slides obtained immediately after the 24-hour image set. Results- Permeability values in the nonischemic tissue (marginal mean±SE: 0.15±0.019 mL/min[Combining Dot Above]100 g) were significantly lower compared to all permeability values in regions of Evans blue extravasation or hemorrhage. Permeability values in regions of weak Evans blue extravasation (0.23±0.016 mL/min[Combining Dot Above]100 g) were significantly lower compared to permeability values of in regions of strong Evans blue extravasation (0.29±0.020 mL/min[Combining Dot Above]100 g) and macroscopic hemorrhage (0.35±0.049 mL/min[Combining Dot Above]100 g). Permeability values in regions of microscopic hemorrhage (0.26±0.024 mL/min[Combining Dot Above]100 g) only differed significantly from values in regions of nonischemic tissue (0.15±0.019 mL/min[Combining Dot Above]100 g). Conclusions- Areas of increased permeability measured in vivo by imaging coincide with blood-brain barrier disruption and hemorrhage observed on gold standard histology. Copyright © 2011 American Heart Association. All rights reserved.

Petersen A.-K.,Institute of Genetic Epidemiology | Zeilinger S.,Research Unit of Molecular Epidemiology | Kastenmuller G.,Institute of Bioinformatics and Systems Biology | Werner R.-M.,Institute of Bioinformatics and Systems Biology | And 20 more authors.
Human Molecular Genetics | Year: 2014

Previously,we reported strong influences of genetic variants on metabolic phenotypes, some of them with clinical relevance. Here, we hypothesize that DNA methylation may have an important and potentially independent effect on human metabolism. Totest this hypothesis,we conducted what is to the best of our knowledge the first epigenome-wide association study (EWAS) between DNA methylation and metabolic traits (metabotypes) in human blood. We assess 649 blood metabolic traits from 1814 participants of the Kooperative Gesundheitsforschung in der Region Augsburg (KORA) population study for association with methylation of 457 004 CpG sites, determined on the Infinium Human Methylation 450 Bead Chip platform. Using the EWAS approach, we identified two types of methylome-metabotype associations. One type is driven by an underlying genetic effect; the other type is independent of genetic variation and potentially driven by common environmental and life-style-dependent factors. We report eight CpG loci atgenome-wide significance that have a genetic variant as confounder (P = 3.9 × 10-20 to 2.0 × 10-108, r2 = 0.036 to 0.221).Seven loci display CpG site-specific associations to metabotypes ,but do not exhibit any underlying genetic signals (P = 9.2 × 10-14 to 2.7 × 10-27, r2 = 0.008 to 0.107). We further identify several groups of CpG loci that associate with a same metabotype, such as 4-vinylphenol sulfate and 4-androsten-3-beta,17-beta-diol disulfate. In these cases, the association between CpG-methylation and metabotype is likely the result of a common external environmental factor, including smoking. Our study shows that analysis of EWAS with large numbers of metabolic traits in large population cohorts are, in principle, feasible. Taken together, our data suggest that DNA methylation plays an important role in regulating human metabolism. © The Author 2013. Published by Oxford University Press.

Schnattinger G.,Technical UniversityMunchen | Eibert T.F.,Technical UniversityMunchen
IEEE Transactions on Antennas and Propagation | Year: 2012

A 3-D imaging approach based on a multilevel fast multipole method inspired hierarchical disaggregation of the broadband plane wave spectrum is introduced to solve the full vectorial electromagnetic inverse source problem based on the knowledge of the radiated fields. In terms of complexity, this algorithm is identical to fast Fourier transform accelerated 3-D imaging techniques. In terms of applicability, the hierarchical disaggregation is advantageous for commonly encountered spherical $k$ -space data. Since the method can be directly combined with the near-field fast multipole translations, both far- and near-field data can be handled conveniently. The investigation includes an analysis of the inherent point spread function and numerical results. © 1963-2012 IEEE.

Rischpler C.,Technical UniversityMunchen | Rischpler C.,DZKH Deutsches Zentrum fur Herz Kreislauf Forschung E.V. | Langwieser N.,TU Munich | Souvatzoglou M.,Technical UniversityMunchen | And 10 more authors.
European Heart Journal Cardiovascular Imaging | Year: 2015

Aims F-18 fluorodeoxyglucose (FDG) myocardial PET imaging is since more than two decades considered to delineate glucose utilization in dysfunctional but viable cardiomyocytes. Late gadolinium enhancement (LGE) MRI was introduced more than a decade ago and identifies increased extravascular space in areas of infarction and scar. Although the physiological foundation differs, both approaches are valuable in the prediction of functional outcome of the left ventricle, but synergistic effects are yet unknown.We aimed to compare the improvement of LV function after 6 months based on the regional FDG uptake and the transmurality of scar by LGE in patients early after acute myocardial infarction (AMI). Methods and results Twenty-eight patients with primary AMI underwent simultaneous PET/MRI for assessment of regional FDG uptake and degree of LGE transmurality 5-7 days after PCI. Follow-up by MRI was performed in 20 patients 6 months later. Myocardium was defined 'PET viable' based on the established threshold of ≥50% FDG uptake compared with remote myocardium or as 'MRI viable' when LGE transmurality of ≤50% was present. Regional wall motion was measured by MRI. Ninety-five dysfunctional segmentswere further analysed regarding regional wall motion recovery. There was a substantial intermethod agreement for segmental LGE transmurality and reduction of FDG uptake (k = 0.65). 'PET viable' and 'MRI viable' segments showed a lower wall motion abnormality score (PET: initial: 1.4±0.6 vs. 1.9±0.8, P < 0.008; follow-up: 0.5±0.7 vs. 1.5±1.0, P < 0.0001; MRI: initial: 1.5±0.6 vs. 2.0±0.8, P < 0.002; follow-up: 0.7±0.8 vs. 1.6±1.0, P < 0.0001) and a better regional wall motion improvement (PET: 20.9±0.7 vs. 20.4±0.7, P < 0.0007; MRI: 20.8±0.7 vs. 20.4±0.7, P < 0.009) compared with 'PET non-viable' or 'MRI non-viable' segments, respectively. Eighteen per cent of the dysfunctional segments showed discrepant findings ('PET non-viable' but 'MRI viable'). At followup, the regional wall motion of these segmentswas inferior compared with 'PET viable/MRI viable' segments (1.1±0.8 vs. 0.5±0.7, P < 0.01), had an inferior functional recovery (20.5±0.6 vs. 20.9±0.7, P < 0.03), but showed no difference compared with concordant 'PET non-viable/MRI non-viable' segments. Conclusion The simultaneous assessment of LGE andFDG uptake using a hybrid PET/MRI system is feasible. The established PET and MRI 'viability' parameter prior to revascularization therapy also predicts accurately the regional outcome of wall motion after AMI. In a small proportion of segments with discrepant FDG PET and LGE MRI findings, FDG uptake was a better predictor for functional recovery. © 2015 The Author.

Leopold M.,University of Western Australia | Volke J.,Technical UniversityMunchen | Huber J.,Technical UniversityMunchen | Dethier D.,Williams College
Earth Surface Processes and Landforms | Year: 2013

The architecture of the critical zone includes the distribution, thickness, and contacts of various types of slope deposits and weathering products such as saprolite and weathered bedrock resting on solid bedrock. A quantitative analysis of architecture is necessary for many model-driven approaches used by pedologic, geomorphic, hydrologic or biologic studies. We have used electrical resistivity tomography, a well-established geophysical technique causing minimum surficial disturbance, to portray the subsurface electrical resistivity differences at three study sites (Green Lakes Valley; Gordon Gulch; Betasso) at the Boulder Creek Critical Zone Observatory (BcCZO). Possible limitations of the technique are discussed. Interpretation of the specific resistivity values using natural outcrops, pits, roadcuts and drilling data as ground truth information allows us to image the critical zone architecture of each site. Green Lakes Valley (3700 MASL), a glacially eroded alpine basin, shows a rather simple, split configuration with coarse blockfields and sediments, partly containing permafrost above bedrock. The critical zone in Gordon Gulch (2650 MASL), a montane basin with rolling hills, and Betasso (1925 MASL), a lower montane basin with v-shaped valleys, is more variable due to a complex Quaternary geomorphic history. Boundaries between overlying stratified slope deposits and saprolite were identified at mean depths of 3.0±2.2m and 4.1±3.6m in the respective sites. The boundary between saprolite and weathered bedrock is deeper in Betasso at 5.8±3.7 m, compared with 4.3±3.0m in Gordon Gulch. In general, the data are consistent with results from seismic studies, but electrical resistivity tomography documents a 0.5-1.5m shallower critical zone above the weathered bedrock on average. Additionally, we document high lateral variability, which results from the weathering and sedimentation history and seems to be a consistent aspect of critical zone architecture within the BcCZO. © 2013 John Wiley & Sons, Ltd.

Roth S.,Technical UniversityMunchen | Matthes F.,Technical UniversityMunchen
Lecture Notes in Informatics (LNI), Proceedings - Series of the Gesellschaft fur Informatik (GI) | Year: 2013

An Enterprise Architecture (EA) embraces an organization'S technical infrastructure, applications, business capabilities, and relationships among them. Evolutionary design is a common characteristic for such an EA. An EA can be considered as a complex system of systems, whereas the actual efforts for its maintainability and evolution have a high influence on the enterprise's capability to quickly respond to market changes. A common means to analyze an EA are visualizations. However, research on visual means for analysis of EA evolutions is scarce. In this paper we outline visual means to analyze the evolution of EAs and motivate research on this topic by outlining related challenges. © Gesellschaft für Informatik, Bonn 2013.

Bruegel M.,Technical UniversityMunchen | Rummeny E.J.,Technical UniversityMunchen
Abdominal Imaging | Year: 2010

Diffusion-weighted MR imaging is increasingly applied to detect and characterize focal hepatic lesions. In this update article, technical aspects regarding diffusion-weighted echo-planar imaging (DW-EPI) of the liver will be addressed, and concepts for image interpretation will be provided. The value of DW-EPI for the detection of hepatic metastases is illustrated on the basis of a review of the literature and our personal experience. In this respect, special emphasis is given to the comparison of DW-EPI with well-established MR imaging techniques such as T2-weighted and contrast-enhanced MR imaging, and advantages and limitations of DW-EPI will be described. Based on the review, it is concluded that DW-EPI is more sensitive than T2-weighted MR imaging and at least as accurate as superparamagnetic iron oxide-enhanced or gadolinium-enhanced MR imaging for the detection of hepatic metastases. Although difficulties occasionally arise in further characterizing small lesions detected with DW-EPI, substantial improvements in the preoperative evaluation of liver metastases in candidates for hepatic resection may be expected. © 2009 Springer Science+Business Media, LLC.

Moser M.,Technical UniversityMunchen | Stelzer R.,University of Ulm
Extremes | Year: 2013

We consider the functional regular variation in the space D of càdlàg functions of multivariate mixed moving average (MMA) processes of the type Xt = ∫ ∫ f(A, t - s) Λ (d A, d s). We give sufficient conditions for an MMA process (Xt) to have càdlàg sample paths. As our main result, we prove that (Xt) is regularly varying in D if the driving Lévy basis is regularly varying and the kernel function f satisfies certain natural (continuity) conditions. Finally, the special case of supOU processes, which are used, e.g., in applications in finance, is considered in detail. © 2013 Springer Science+Business Media New York.

Malinowsky K.,TU Munich | Wolff C.,TU Munich | Berg D.,TU Munich | Schuster T.,TU Munich | And 7 more authors.
Translational Oncology | Year: 2012

The supporting role of urokinase-type plasminogen activator (uPA) and its inhibitor plasminogen activator inhibitor 1 (PAI-1) in migration and invasion is well known. In addition, both factors are key components in cancer cell- related signaling. However, little information is available for uPA and PAI-1-associated signaling pathways in primary cancers and corresponding lymph node metastases. The aim of this study was to compare the expression of uPA and PAI-1-associated signaling proteins in 52 primary breast cancers and corresponding metastases. Proteins were extracted from formalin-fixed paraffin-embedded tissue samples of the primary tumors and metastases. Protein lysates were subsequently analyzed by reverse phase protein array for the expression of members of the PI3K/AKT (FAK, GSK3-β, ILK, pGSK3-β, PI3K, and ROCK) and the MAPK pathways (pp38, pSTAT3, and p38). A solid correlation of uPA expression existed between primary tumors and metastases, whereas PAI-1 expression did not significantly correlate between them. The correlations of uPA and PAI-1 with signaling pathways found in primary tumors did not persist in metastases. Analysis of single molecules revealed that some correlated well between tumors and metastases (FAK, pGSK3-β, ILK, Met, PI3K, ROCK, uPA, p38, and pp38), whereas others did not (PAI-1 and GSK3-β).Whether the expression of a protein correlated between tumor and metastasis or not was independent of the pathway the protein is related to. These findings hint at a complete deregulation of uPA and PAI-1-related signaling in metastases, which might be the reason why uPA and PAI-1 reached clinical relevance only for lymph node- negative breast cancer tissues. © 2012 Neoplasia Press, Inc. All rights reserved.

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