Central actions of corticotropin-releasing hormone (CRH) on behavioral, neuroendocrine, and cardiovascular regulation: brain corticoid receptor involvement

The effect of intracerebroventricular (icv) infused corticotropin-releasing hormone (CRH), 300 ng, infused at a rate of 16.67 ng/min during 18 min and its relation to the functioning of brain corticoid receptors was investigated in freely moving rats in their home cages. Behavior was sampled before, during, and after the CRH infusion. Cardiovascular measurements were made via a chronically implanted catheter in the descending aorta. Blood samples were withdrawn to determine adrenal hormone concentration. Central administration of the brain mineralocorticoid-like receptor (MR) antagonist (RU 28318, 100 ng) and the glucocorticoid receptor (GR) antagonist (RU 38486, 100 ng) 60 min before CRH infusion served to manipulate adrenal steroid states in the brain. CRH infusion caused behavioral activation which was associated with an increase in heart rate (HR) and mean arterial blood pressure (MAP). Increased plasma corticosterone and norepinephrine levels were observed, while a minor elevation of epinephrine (E) levels also occurred. Both corticoid receptor antagonists failed to affect the CRH-induced behavioral activation. Administration of the GR antagonist significantly enhanced the magnitude of the CRH-induced increase in E, whereas the effect of the MR antagonist just failed to reach significance. These findings suggest the involvement of central corticoid receptors in sympathoadrenomedullary feedback mechanisms. The MR antagonist elevated baseline MAP probably thereby suppressing the magnitude of the CRH response. The increase in HR was diminished by both antagonists shortly after CRH infusion. Together, the data suggest involvement of brain corticosteroid receptor-mediated processes in neuroendocrine and cardiovascular effects of CRH.     

The involvement of brain-derived neurotrophic factor in hippocampal long-term potentiation revealed by gene targeting experiments

Brain-derived neurotrophic factor (BDNF) is a member of the NGF gene family, which has been shown to influence the survival and differentiation of specific classes of neurons in vitro and in vivo. The possibility that neurotrophins are also involved in processes of neuronal plasticity has only recently begun to receive attention. To determine whether BDNF has a function in processes like long-term potentiation (LTP), we produced a strain of mice with a deletion in the coding sequence of the BDNF-gene. We then used hippocampal slices from these mice to investigate whether LTP is affected by this mutation. Mutant mice showed significantly weaker LTP in the CA1 region. The magnitude of the potentiation as well as the percentage of cases in which LTP could be induced successfully was clearly reduced whereas important pharmacological and morphological control parameters in the hippocampus of these animals were unaffected. Adenoviral vectors were used to re-express BDNF in acute slices of BDNF-knock-out mice. In most cases LTP could be rescued with this approach. These results suggest that BDNF has an important functional role in the expression of LTP in the hippocampus.     

Effects of four types of non-obtrusive feedback on computer behaviour, task performance and comfort

This study investigated the effects of non-obtrusive feedback on continuous lifted hand/finger behaviour, task performance and comfort. In an experiment with 24 participants the effects of two visual and two tactile feedback signals were compared to a no-feedback condition in a computer task. Results from the objective measures showed that all types of feedback were equally effective to reduce lifted hand/finger behaviour (effectiveness) compared to absence of feedback, while task performance was not affected (efficiency). In contrast to objective measures, subjective user experience was significantly different for the four types of feedback signals. Continuous tactile feedback appeared to be the best signal; not only the effectiveness and efficiency were rated reasonable, it also scored best on perceived match between signal and required action. This study shows the importance of including user experiences when investigating usability of feedback signals. Non-obtrusive feedback embedded in products and environments may successfully be used to support office workers to adopt healthy, productive and comfortable working behaviour.     

EURECA: European-Japanese Microcalorimeter Array

The EURECA project aims to demonstrate technological readiness of a micro-calorimeter array for application in future X-ray astronomy missions, like Constellation-X, EDGE, and XEUS. The prototype instrument consists of a 5×5 pixel array of TES-based micro-calorimeters read out by two SQUID-amplifier channels using frequency-domain-multiplexing (FDM) with digital base-band feedback. The detector array is cooled by a cryogen-free cryostat consisting of a pulse tube cooler and a two stage ADR. Initial tests of the system at the PTB beam line of the BESSY synchrotron showed stable performance and an X-ray energy resolution of 1.5 eV at 250 eV for read-out of one TES-pixel only. Next step is deployment of FDM to read-out the full array. Full performance demonstration is expected end 2008.      

Datenschutzfreundliche Authentisierung mit Fingerabdrücken

Ein wesentlicher Faktor für die Akzeptanz biometrischer Authentisierungsverfahren ist der zuverl?ssige Schutz der pers?nlichen Daten der Nutzer. Da für biometrische Verfahren immer die Hinterlegung von Referenzdaten erforderlich ist, muss auf deren sichere Speicherung ein besonderes Augenmerk gelegt werden. Eine Alternative hierfür bieten sogenannte "Template Protection Verfahren“. Der vorliegende Beitrag stellt ein solches Verfahren vor und gibt einen Einblick in die praktische Umsetzung.     

Multicore Liquid Perfluorocarbon‐Loaded Multimodal Nanoparticles for Stable Ultrasound and 19F MRI Applied to In Vivo Cell Tracking

Ultrasound is the most commonly used clinical imaging modality. However, in applications requiring cell‐labeling, the large size and short active lifetime of ultrasound contrast agents limit their longitudinal use. Here, 100 nm radius, clinically applicable, polymeric nanoparticles containing a liquid perfluorocarbon, which enhance ultrasound contrast during repeated ultrasound imaging over the course of at least 48 h, are described. The perfluorocarbon enables monitoring the nanoparticles with quantitative ¹⁹F magnetic resonance imaging, making these particles effective multimodal imaging agents. Unlike typical core–shell perfluorocarbon‐based ultrasound contrast agents, these nanoparticles have an atypical fractal internal structure. The nonvaporizing highly hydrophobic perfluorocarbon forms multiple cores within the polymeric matrix and is, surprisingly, hydrated with water, as determined from small‐angle neutron scattering and nuclear magnetic resonance spectroscopy. Finally, the nanoparticles are used to image therapeutic dendritic cells with ultrasound in vivo, as well as with ¹⁹F MRI and fluorescence imaging, demonstrating their potential for long‐term in vivo multimodal imaging.     

Ultra compact multitip scanning tunneling microscope with a diameter of 50 mm

We present a multitip scanning tunneling microscope (STM) where four independent STM units are integrated on a diameter of 50 mm. The coarse positioning of the tips is done under the control of an optical microscope or scanning electron microscopy in vacuum. The heart of this STM is a new type of piezoelectric coarse approach called KoalaDrive. The compactness of the KoalaDrive allows building a four-tip STM as small as a single-tip STM with a drift of less than 0.2 nm/min at room temperature and lowest resonance frequencies of 2.5 kHz (xy) and 5.5 kHz (z). We present as examples of the performance of the multitip STM four point measurements of silicide nanowires and graphene.