110 research outputs found

    Fahrdynamikoptimierung mittels Torque Vectoring bei einem bauraumoptimierten Elektrofahrzeug

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    Durch bauraumoptimierte Anordnung der Antriebskomponenten eines Elektrofahrzeugs können sich unkonventionelle Achslasten ergeben, welche in der Fahrdynamikauslegung berücksichtigt werden müssen. Die BMW Group Forschung und Technik entwickelt zusammen mit dem Deutschen Zentrum für Luft- und Raumfahrt (DLR) und dem Lehrstuhl für Regelungs- und Steuerungssysteme am Karlsruher Institut für Technologie (KIT) ein Torque-Vectoring-Regelungskonzept. Trotz der fahrdynamischen Herausforderung hoher Hinterachslasten wird dadurch ein ansprechendes und sicheres Fahrverhalten erzielt

    Implementation and Perceptual Evaluation of a Simulation Method for Coupled Rooms in Higher Order Ambisonics

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    A fast and perceptively plausible method for rendering acoustic scenarios with moving sources and moving listeners is presented. The method is principally suited for application in dynamic and interactive evaluation environments (e.g., for hearing aid development), psycho-physics with adaptively changing the spatial configuration, or simulation and computer games. The simulation distinguishes between the direct sound, sound reflected and diffracted by objects of limited size, diffuse sound surrounding the listener, e.g., diffuse background sounds and diffuse reverberation, and ’radiating holes’ for simulation of coupled adjacent rooms. Instead of providing its own simulation of room reverberation, the proposed simulation method generates appropriate output signals for external room reverberation simulators (e.g., see contribution by Wendt et al.). The output of such room reverberation simulators is then taken either as diffuse surrounding sound if the listener position is within the simulated room, or as input into a ’radiating hole’, if the listener is in an adjacent room. Subjective evaluations are performed by comparing measured and synthesized transitions between coupled rooms.DFG, FOR 1732, Individualisierte Hörakustik: Modelle, Algorithmen und Systeme für die Sicherstellung der akustischen Wahrnehmung für alle in allen Situatione

    Object Fusion and Localization Dominance in Real Time Spatial Processing of Acoustics Sources Using Higher Order Ambisonics

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    Presented at the 17th International Conference on Auditory Display (ICAD2011), 20-23 June, 2011 in Budapest, Hungary.The psycho-acoustic properties fusion and localization dominance were measured for a rotating target and a fixed-position distractor, which was a delayed copy of the target. Higher-order Ambisonics was used for spatial presentation of the target. The relative delay between distractor and target, the listener position within the play- back system and the angular speed of the target were varied. For measurement of the localization dominance a pointer device was developed, which allows measurement of the perceived direction in real-time, synchronized to the target motion. The aim of this study was to find the limitations of the higher- order Ambisonics setup regarding the position of listeners and sources, as well as the potential influence of source speed and continuity on these limitations. A small effect of continuity on the breakdown of localization dominance was found. The results of this study are qualitatively in line with the predictions of the precedence effect. They can directly be used to optimize an artis- tic concert installation where acoustic sources are processed and presented as virtual moving sources. The setup is also suited for new hearing aid evaluation methods

    Metabolic Actions of Estrogen Receptor Beta (ERβ) are Mediated by a Negative Cross-Talk with PPARγ

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    Estrogen receptors (ER) are important regulators of metabolic diseases such as obesity and insulin resistance (IR). While ERα seems to have a protective role in such diseases, the function of ERβ is not clear. To characterize the metabolic function of ERβ, we investigated its molecular interaction with a master regulator of insulin signaling/glucose metabolism, the PPARγ, in vitro and in high-fat diet (HFD)-fed ERβ -/- mice (βERKO) mice. Our in vitro experiments showed that ERβ inhibits ligand-mediated PPARγ-transcriptional activity. That resulted in a blockade of PPARγ-induced adipocytic gene expression and in decreased adipogenesis. Overexpression of nuclear coactivators such as SRC1 and TIF2 prevented the ERβ-mediated inhibition of PPARγ activity. Consistent with the in vitro data, we observed increased PPARγ activity in gonadal fat from HFD-fed βERKO mice. In consonance with enhanced PPARγ activation, HFD-fed βERKO mice showed increased body weight gain and fat mass in the presence of improved insulin sensitivity. To directly demonstrate the role of PPARγ in HFD-fed βERKO mice, PPARγ signaling was disrupted by PPARγ antisense oligonucleotide (ASO). Blockade of adipose PPARγ by ASO reversed the phenotype of βERKO mice with an impairment of insulin sensitization and glucose tolerance. Finally, binding of SRC1 and TIF2 to the PPARγ-regulated adiponectin promoter was enhanced in gonadal fat from βERKO mice indicating that the absence of ERβ in adipose tissue results in exaggerated coactivator binding to a PPARγ target promoter. Collectively, our data provide the first evidence that ERβ-deficiency protects against diet-induced IR and glucose intolerance which involves an augmented PPARγ signaling in adipose tissue. Moreover, our data suggest that the coactivators SRC1 and TIF2 are involved in this interaction. Impairment of insulin and glucose metabolism by ERβ may have significant implications for our understanding of hormone receptor-dependent pathophysiology of metabolic diseases, and may be essential for the development of new ERβ-selective agonists

    Quality assurance process within the RAdiosurgery for VENtricular TAchycardia (RAVENTA) trial for the fusion of electroanatomical mapping and radiotherapy planning imaging data in cardiac radioablation

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    A novel quality assurance process for electroanatomical mapping (EAM)-to-radiotherapy planning imaging (RTPI) target transport was assessed within the multi-center multi-platform framework of the RAdiosurgery for VENtricular TAchycardia (RAVENTA) trial. A stand-alone software (CARDIO-RT) was developed to enable platform independent registration of EAM and RTPI of the left ventricle (LV), based on pre-generated radiotherapy contours (RTC). LV-RTC were automatically segmented into the American-Heart-Association 17-segment-model and a manual 3D-3D method based on EAM 3D-geometry data and a semi-automated 2D-3D method based on EAM screenshot projections were developed. The quality of substrate transfer was evaluated in five clinical cases and the structural analyses showed substantial differences between manual target transfer and target transport using CARDIO-RT

    Echocardiographic parameters indicating left atrial reverse remodeling after catheter ablation for atrial fibrillation

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    BackgroundThe echocardiographic parameters total atrial conduction time (PA-TDI duration), left atrial (LA) volume index (LAVI), and LA strain reflect adverse atrial remodeling and predict atrial fibrillation (AF).ObjectivesThe aim of this study was to investigate echocardiographic parameters indicating reverse LA remodeling and potential associations with AF recurrence after pulmonary vein isolation (PVI).MethodsThis prospective observational study consecutively enrolled patients scheduled for PVI for symptomatic AF. Electrocardiogram (ECG) test and transthoracic echocardiography were performed the day before and after PVI and again 3 months later. AF recurrence was determined by Holter ECG at 3 months, and telephone follow-up at 12 months, after PVI. The parameters of LA remodeling [PA-TDI, LAVI, and LA strain analysis: reservoir strain (LASr), conduit strain (LAScd), contraction strain (LASct)] were determined by transthoracic echocardiography.ResultsA total of 48 patients were included in the study (mean age: 61.4 ± 12.2 years). PA-TDI significantly decreased the day after PVI compared with the baseline (septal PA-TDI 103 ± 13 vs. 82 ± 14.9 ms, p ≤ 0.001; lateral PA-TDI 122.4 ± 14.8 vs. 106.9 ± 14.4 ms, p ≤ 0.001) and at the 3-month follow-up (septal PA-TDI: 77.8 ± 14.5, p ≤ 0.001; lateral PA-TDI 105.2 ± 16.1, p ≤ 0.001). LAVI showed a significant reduction at the 3-month follow-up compared with the baseline (47.7 ± 14.4 vs. 40.5 ± 9.7, p < 0.05). LASr, LAScd, and LASct did not change after PVI compared with the baseline. AF recurred in 10 patients after PVI (21%). Septal PA-TDI, septal a', and LAVI/a' determined the day after PVI were associated with AF recurrence.ConclusionChanges in echocardiographic parameters of LA remodeling and function indicate that functional electromechanical recovery preceded morphological reverse remodeling of the left atrium after PVI. Furthermore, these changes in echocardiographic parameters indicating LA reverse remodeling after PVI may identify patients at high risk of AF recurrence

    The IMAGEN study: a decade of imaging genetics in adolescents

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    Imaging genetics offers the possibility of detecting associations between genotype and brain structure as well as function, with effect sizes potentially exceeding correlations between genotype and behavior. However, study results are often limited due to small sample sizes and methodological differences, thus reducing the reliability of findings. The IMAGEN cohort with 2000 young adolescents assessed from the age of 14 onwards tries to eliminate some of these limitations by offering a longitudinal approach and sufficient sample size for analyzing gene-environment interactions on brain structure and function. Here, we give a systematic review of IMAGEN publications since the start of the consortium. We then focus on the specific phenotype ‘drug use’ to illustrate the potential of the IMAGEN approach. We describe findings with respect to frontocortical, limbic and striatal brain volume, functional activation elicited by reward anticipation, behavioral inhibition, and affective faces, and their respective associations with drug intake. In addition to describing its strengths, we also discuss limitations of the IMAGEN study. Because of the longitudinal design and related attrition, analyses are underpowered for (epi-) genome-wide approaches due to the limited sample size. Estimating the generalizability of results requires replications in independent samples. However, such densely phenotyped longitudinal studies are still rare and alternative internal cross-validation methods (e.g., leave-one out, split-half) are also warranted. In conclusion, the IMAGEN cohort is a unique, very well characterized longitudinal sample, which helped to elucidate neurobiological mechanisms involved in complex behavior and offers the possibility to further disentangle genotype × phenotype interactions

    The G2A Receptor Controls Polarization of Macrophage by Determining Their Localization Within the Inflamed Tissue

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    Macrophages are highly versatile cells, which acquire, depending on their microenvironment, pro- (M1-like), or antiinflammatory (M2-like) phenotypes. Here, we studied the role of the G-protein coupled receptor G2A (GPR132), in chemotactic migration and polarization of macrophages, using the zymosan-model of acute inflammation. G2A-deficient mice showed a reduced zymosan-induced thermal hyperalgesia, which was reversed after macrophage depletion. Fittingly, the number of M1-like macrophages was reduced in the inflamed tissue in G2A-deficient mice. However, G2A activation was not sufficient to promote M1-polarization in bone marrow-derived macrophages. While the number of monocyte-derived macrophages in the inflamed paw was not altered, G2A-deficient mice had less macrophages in the direct vicinity of the origin of inflammation, an area marked by the presence of zymosan, neutrophil accumulation and proinflammatory cytokines. Fittingly neutrophil efferocytosis was decreased in G2A-deficient mice and several lipids, which are released by neutrophils and promote G2A-mediated chemotaxis, were increased in the inflamed tissue. Taken together, G2A is necessary to position macrophages in the proinflammatory microenvironment surrounding the center of inflammation. In absence of G2A the macrophages are localized in an antiinflammatory microenvironment and macrophage polarization is shifted toward M2-like macrophages

    Persister cell phenotypes contribute to poor patient outcomes after neoadjuvant chemotherapy in PDAC

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    Neoadjuvant chemotherapy can improve the survival of individuals with borderline and unresectable pancreatic ductal adenocarcinoma; however, heterogeneous responses to chemotherapy remain a significant clinical challenge. Here, we performed RNA sequencing (n = 97) and multiplexed immunofluorescence (n = 122) on chemo-naive and postchemotherapy (post-CTX) resected patient samples (chemoradiotherapy excluded) to define the impact of neoadjuvant chemotherapy. Transcriptome analysis combined with high-resolution mapping of whole-tissue sections identified GATA6 (classical), KRT17 (basal-like) and cytochrome P450 3A (CYP3A) coexpressing cells that were preferentially enriched in post-CTX resected samples. The persistence of GATA6hi and KRT17hi cells post-CTX was significantly associated with poor survival after mFOLFIRINOX (mFFX), but not gemcitabine (GEM), treatment. Analysis of organoid models derived from chemo-naive and post-CTX samples demonstrated that CYP3A expression is a predictor of chemotherapy response and that CYP3A-expressing drug detoxification pathways can metabolize the prodrug irinotecan, a constituent of mFFX. These findings identify CYP3A-expressing drug-tolerant cell phenotypes in residual disease that may ultimately inform adjuvant treatment selection
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