Renin, endothelial no synthase and endothelin gene expression in the 2Kidney-1clip goldblatt model of long-term renovascular hypertension

<p>Abstract</p> <p>Objective</p> <p>Numerous reports have shown the influence of renin, nitric oxide (NO) and the endothelin (ET) systems for regulation of blood pressure and renal function. Furthermore, interactions between these peptides have been reported. Aim of our study was to investigate the relative contribution of these compounds in long-term renovascular hypertension/renal ischemia.</p> <p>Methods</p> <p>Hypertension/left-sided renal ischemia was induced using the 2K1C-Goldblatt rat model. Renal renin, ET-1, ET-3 and endothelial NO synthase (eNOS) gene expression was measured by means of RNAse protection assay at different timepoints up to 10 weeks after induction of renal artery stenosis.</p> <p>Results</p> <p>Plasma renin activity and renal renin gene expression in the left kidney were increased in the clipped animals while eNOS expression was unchanged. Furthermore, an increase in ET-1 expression and a decrease of ET-3 expression was detected in early stenosis.</p> <p>Conclusions</p> <p>While renin is obviously involved in regulation of blood pressure and renal function in unilateral renal artery stenosis, ET-1, ET-3 and endothelium derived NO do not appear to play an important role in renal adaptation processes in long-term renal artery stenosis, although ET-1 and ET-3 might be involved in short-term adaptation processes.</p

Limitations of human 3D-force discrimination

Internet-based telepresence and teleaction systems require packet-based transmission of haptic data and typically generate high packet rates between operator and teleoperator. This leads to the necessity of packet rate reduction techniques. The so-called deadband approach presented earlier by the authors uses a psychophysically motivated scheme based on Weber’s difference threshold (just noticable difference- JND) where force sample values are only transmitted if the change exceeds this threshold. This approach has been extended to three dimensions resulting in an additional perceptual domain- namely force direction. An experimental evaluation with human subjects was conducted in order to examine the change of the JND in 3D when force magnitude and force direction are combined. Our results show that the extension into dimensions yields to an increased JND in certain cases. Thus, higher compression ratios of haptic data and reduction in number of packets sent over the network can be reached. 1

Temporal synchronization of multiple audio signals

Given the proliferation of consumer media recording de-vices, events often give rise to a large number of recordings. These recordings are taken from different spatial positions and do not have reliable timestamp information. In this pa-per, we present two robust graph-based approaches for syn-chronizing multiple audio signals. The graphs are constructed atop the over-determined system resulting from pairwise sig-nal comparison using cross-correlation of audio features. The first approach uses a Minimum Spanning Tree (MST) tech-nique, while the second uses Belief Propagation (BP) to solve the system. Both approaches can provide excellent solutions and robustness to pairwise outliers, however the MST ap-proach is much less complex than BP. In addition, an exper-imental comparison of audio features-based synchronization shows that spectral flatness outperforms the zero-crossing rate and signal energy. Index Terms — Multi-signal synchronization, audio fea-ture analysis, minimum spanning tree, belief propagation 1