Magnetic properties of antiferromagnetically coupled CoFeB/Ru/CoFeB

This work reports on the thermal stability of two amorphous CoFeB layers coupled antiferromagnetically via a thin Ru interlayer. The saturation field of the artificial ferrimagnet which is determined by the coupling, J, is almost independent on the annealing temperature up to more than 300 degree C. An annealing at more than 325 degree C significantly increases the coercivity, Hc, indicating the onset of crystallization.Comment: 4 pages, 3 figure

Moho depth across the Trans-European Suture Zone from P-and S-receiver functions

The Mohorovicic discontinuity, Moho for short, which marks the boundary between crust and mantle, is the main first-order structure within the lithosphere. Geodynamics and tectonic evolution determine its depth level and properties. Here, we present a map of the Moho in central Europe across the Teisseyre-Tornquist Zone, a region for which a number of previous studies are available. Our results are based on homogeneous and consistent processing of P- and S-receiver functions for the largest passive seismological data set in this region yet, consisting of more than 40 000 receiver functions from almost 500 station. Besides, we also provide new results for the crustal Vp/Vs ratio for the whole area. Our results are in good agreement with previous, more localized receiver function studies, as well as with the interpretation of seismic profiles, while at the same time resolving a higher level of detail than previous maps covering the area, for example regarding the Eifel Plume region, Rhine Graben and northern Alps. The close correspondence with the seismic data regarding crustal structure also increases confidence in use of the data in crustal corrections and the imaging of deeper structure, for which no independent seismic information is available. In addition to the pronounced, stepwise transition from crustal thicknesses of 30km in Phanerozoic Europe to more than 45 beneath the East European Craton, we can distinguish other terrane boundaries based on Moho depth as well as average crustal Vp/Vsratio and Moho phase amplitudes. The terranes with distinct crustal properties span a wide range of ages, from Palaeoproterozoic in Lithuania to Cenozoic in the Alps, reflecting the complex tectonic history of Europe. Crustal thickness and properties in the study area are also markedly influenced by tectonic overprinting, for example the formation of the Central European Basin System, and the European Cenozoic Rift System. In the areas affected by Cenozoic rifting and volcanism, thinning of the crust corresponds to lithospheric updoming reported in recent surface wave and S-receiver function studies, as expected for thermally induced deformation. The same correlation applies for crustal thickening, not only across the Trans-European Suture Zone, but also within the southern part of the Bohemian Massif. A high Poisson’s ratio of 0.27 is obtained for the craton, which is consistent with a thick mafic lower crust. In contrast, we typically find Poisson’s ratios around 0.25 for Phanerozoic Europe outside of deep sedimentary basins. Mapping of the thickness of the shallowest crustal layer, that is low-velocity sediments or weathered rock, indicates values in excess of 6km for the most pronounced basins in the study area, while thicknesses of less than 4km are found within the craton, central Germany and most of the Czech Republic.Peer reviewe

Creating sparser prediction models of treatment outcome in depression: a proof-of-concept study using simultaneous feature selection and hyperparameter tuning

Background Predicting treatment outcome in major depressive disorder (MDD) remains an essential challenge for precision psychiatry. Clinical prediction models (CPMs) based on supervised machine learning have been a promising approach for this endeavor. However, only few CPMs have focused on model sparsity even though sparser models might facilitate the translation into clinical practice and lower the expenses of their application. Methods In this study, we developed a predictive modeling pipeline that combines hyperparameter tuning and recursive feature elimination in a nested cross-validation framework. We applied this pipeline to a real-world clinical data set on MDD treatment response and to a second simulated data set using three different classification algorithms. Performance was evaluated by permutation testing and comparison to a reference pipeline without nested feature selection. Results Across all models, the proposed pipeline led to sparser CPMs compared to the reference pipeline. Except for one comparison, the proposed pipeline resulted in equally or more accurate predictions. For MDD treatment response, balanced accuracy scores ranged between 61 and 71% when models were applied to hold-out validation data. Conclusions The resulting models might be particularly interesting for clinical applications as they could reduce expenses for clinical institutions and stress for patients

Imagery of negative interpersonal experiences influence the neural mechanisms of social interaction

Negative interpersonal experiences are a key contributor to psychiatric disorders. While previous research has shown that negative interpersonal experiences influence social cognition, less is known about the effects on participation in social interactions and the underlying neurobiology. To address this, we developed a new naturalistic version of a gaze-contingent paradigm using real video sequences of gaze behaviour that respond to the participants' gaze in real-time in order to create a believable and continuous interactive social situation. Additionally, participants listened to two autobiographical audio-scripts that guided them to imagine a recent stressful and a relaxing situation and performed the gaze-based social interaction task before and after the presentation of either the stressful or the relaxing audio-script. Our results demonstrate that the social interaction task robustly recruits brain areas with known involvement in social cognition, namely the medial prefrontal cortex, bilateral temporoparietal junction, superior temporal sulcus as well as the precuneus. Imagery of negative interpersonal experiences compared to relaxing imagery led to a prolonged change in affective state and to increased brain responses during the subsequent social interaction paradigm in the temporoparietal junction, medial prefrontal cortex, anterior cingulate cortex, precuneus and inferior frontal gyrus. Taken together this study presents a new naturalistic social interaction paradigm suitable to study the neural mechanisms of social interaction and the results demonstrate that the imagery of negative interpersonal experiences affects social interaction on neural levels

Pupil Dilation during Reward Anticipation Is Correlated to Depressive Symptom Load in Patients with Major Depressive Disorder

Depression is a debilitating disorder with high prevalence and socioeconomic cost, but the brain-physiological processes that are altered during depressive states are not well understood. Here, we build on recent findings in macaques that indicate a direct causal relationship between pupil dilation and anterior cingulate cortex mediated arousal during anticipation of reward. We translated these findings to human subjects with concomitant pupillometry/fMRI in a sample of unmedicated participants diagnosed with major depression and healthy controls. We could show that the upregulation and maintenance of arousal in anticipation of reward was disrupted in patients in a symptom-load dependent manner. We could further show that the failure to maintain reward anticipatory arousal showed state-marker properties, as it tracked the load and impact of depressive symptoms independent of prior diagnosis status. Further, group differences of anticipatory arousal and continuous correlations with symptom load were not traceable only at the level of pupillometric responses, but were mirrored also at the neural level within salience network hubs. The upregulation and maintenance of arousal during reward anticipation is a novel translational and well-traceable process that could prove a promising gateway to a physiologically informed patient stratification and targeted interventions

Catalytic enantioselective intermolecular cycloadditions of 2-diazo-3,6-diketoester-derived carbonyl ylides with alkene dipolarophiles

Catalyzed cascade reactions that generate molecular complexity rapidly and in an enantioselective manner are attractive methods for asymmetric synthesis. In the present article, chiral rhodium catalysts are shown to effect such a transformation by using a range of 2-diazo-3,6-diketoesters with bicyclo[2.2.1]alkenes and styrenes as reaction partners. The reactions are likely to proceed by formation of a catalyst-complexed carbonyl ylide from the diazo compound, followed by intermolecular cycloaddition with the alkene dipolarophile. It was possible to obtain high levels of asymmetric induction [up to 89% enantiomeric excess (ee) and 92% ee for the two chiral catalysts investigated]. Enantioselectivity is not highly sensitive to substituent variation at the ketone that forms the ylide; however, branching does improve ee. Observations of dipolarophile-dependent enantiofacial selectivity in the cycloadditions indicate that the dipolarophile can be intimately involved in the enantiodiscrimination process