Protective effect of BDNF against beta-amyloid induced neurotoxicity in vitro and in vivo in rats

We examined the potential protective effect of BDNF against β-amyloid-induced neurotoxicity in vitro and in vivo in rats. In neuronal cultures, BDNF had specific and dose-response protective effects on neuronal toxicity induced by Aβ1-42 and Aβ25-35. It completely reversed the toxic action induced by Aβ1-42 and partially that induced by Aβ25-35. These effects involved TrkB receptor activation since they were inhibited by K252a. Catalytic BDNF receptors (TrkB.FL) were localized in vitro in cortical neurons (mRNA and protein). In in vivo experiments, Aβ25-35 was administered into the indusium griseum or the third ventricle and several parameters were measured 7 days later to evaluate potential Aβ25-35/BDNF interactions, i.e. local measurement of BDNF release, number of hippocampal hilar cells expressing SRIH mRNA and assessment of the corpus callosum damage (morphological examination, pyknotic nuclei counting and axon labeling with anti-MBP antibody). We conclude that BDNF possesses neuroprotective properties against toxic effects of Aβ peptides

Clinical fMRI: Evidence for a 7 T benefit over 3 T

Despite there being an increasing number of installations of ultra high field MR systems (> 3 T) in clinical environments, no functional patient investigations have yet examined possible benefits for functional diagnostics. Here we performed presurgical localization of the primary motor hand area on 3 T and 7 T Siemens scanners with identical investigational procedures and comparable system specific sequence optimizations. Results from 17 patients showed significantly higher functional sensitivity of the 7 T system measured via percent signal change, mean t-values, number of suprathreshold voxels and contrast to noise ratio. On the other hand, 7 T data suffered from a significant increase of artifacts (ghosting, head motion). We conclude that ultra high field systems provide a clinically relevant increase of functional sensitivity for patient investigations

Religiosität international vergleichen

For quite some time there has been widespread consensus in the social sciences that religiosity is a multidimensional and multifaceted phenomenon (see for example Glock 1962; Storm 2009). Individuals may be very religious with respect to one dimension and less so towards another. Previous research has identified various typologies, also called religious profiles, showing different combinations of religious multidimensionality within and across countries. This paper identifies dominant cross-national profiles of religiosity and (1) examines whether there is one valid typology worldwide, or if some countries show profiles more similar to one another than to others; (2) tests the results for invariance to examine whether it is actually appropriate to compare the empirically found typologies of religiosity cross-nationally and (3) looks at the impact of denomination for profile formation. The results reveal that (1) there is a valid typology worldwide, but instead of showing specific characteristics, profiles can be ordered on a single latent continuum from low to high levels of religiosity. (2) It is almost impossible to establish full invariance across countries with a comprehensive set of variables measuring religiosity, but partial homogeneity can be achieved. Contrary to all theoretical expectations, the analyses imply (3) that denomination is not a crucial impact factor for religious profile formation.In den Sozialwissenschaften herrscht die einheitliche Auffassung, Religion sei ein sowohl mehrdimensionales als auch facettenreiches Phänomen (siehe zum Beispiel Glock 1962; Storm 2009). Demnach können Individuen im Hinblick auf eine Dimension sehr religiös und gleichzeitig in Hinblick auf eine andere Dimension weniger religiös sein. Frühere Studien haben verschiedene Typologien (religiöse Profile) identifiziert, die verschiedene Kombinationen religiöser Mehrdimensionalität innerhalb und über Länder hinweg aufweisen. Der vorliegende Artikel identifiziert dominante, länderübergreifende religiöse Profile und untersucht, ob es eine weltweit gültige Typologie gibt oder ob die religiösen Profile einiger Länder sich stärker ähneln als die anderer Länder. Um herauszufinden, ob ein länderübergreifender Vergleich der empirisch identifizierten Profile zulässig ist, werden die Ergebnisse auf Invarianz überprüft. Anschließend werden die Strukturen der religiösen Profile auf den Einfluss von Religionen bzw. Konfessionen untersucht. Die Ergebnisse belegen die Existenz einer validen, länderübergreifenden Typologie. Allerdings weisen die religiösen Profile keine speziellen Muster auf, sondern lassen sich auf einem einzelnen Kontinuum religiöser Intensität verorten. Es zeigt sich außerdem, dass es fast unmöglich ist, bei einer umfassenden Anzahl von Variablen zur Messung von Religiosität strukturelle Invarianz über Länder hinweg nachzuweisen. Partielle Invarianz hingegen konnte bestätigt werden. Entgegen aller theoretischen Erwartungen implizieren die Analysen, dass Religionen bzw. Konfessionen sich nicht entscheidend auf die Bildung religiöser Profile auswirken

Magnetic vortex core reversal by excitation with short bursts of an alternating field

Van Waeyenberge B, Puzic A, Stoll H, et al. Magnetic vortex core reversal by excitation with short bursts of an alternating field. NATURE. 2006;444(7118):461-464.The vortex state, characterized by a curling magnetization, is one of the equilibrium configurations of soft magnetic materials(1-4) and occurs in thin ferromagnetic square and disk-shaped elements of micrometre size and below. The interplay between the magneto-static and the exchange energy favours an in-plane, closed flux domain structure. This curling magnetization turns out of the plane at the centre of the vortex structure, in an area with a radius of about 10 nanometres-the vortex core(5-7). The vortex state has a specific excitation mode: the in-plane gyration of the vortex structure about its equilibrium position(8-10). The sense of gyration is determined by the vortex core polarization(11). Here we report on the controlled manipulation of the vortex core polarization by excitation with small bursts of an alternating magnetic field. The vortex motion was imaged by time-resolved scanning transmission X-ray microscopy(12). We demonstrate that the sense of gyration of the vortex structure can be reversed by applying short bursts of the sinusoidal excitation field with amplitude of about 1.5 mT. This reversal unambiguously indicates a switching of the out-of-plane core polarization. The observed switching mechanism, which can be understood in the framework of micromagnetic theory, gives insights into basic magnetization dynamics and their possible application in data storage