Dynamics of tidal synchronization and orbit circularization of celestial bodies

PACS number s : 05.45.Xt, 05.45.Gg, 95.10.Ce, 96.15.DeWe take a dynamical-systems approach to study the qualitative dynamical aspects of the tidal locking of the rotation of secondary celestial bodies with their orbital motion around the primary. We introduce a minimal model including the essential features of gravitationally induced elastic deformation and tidal dissipation that demonstrates the details of the energy transfer between the orbital and rotovibrational degrees of freedom. Despite its simplicity, our model can account for both synchronization into the 1:1 spin-orbit resonance and the circularization of the orbit as the only true asymptotic attractors, together with the existence of relatively long-lived metastable orbits with the secondary in p:q synchronous rotationWe acknowledge projects OTKA T72037 Hungary , Hielocris Spain , the Human Frontier Science Program I.T. , MCI project CGL-2008-06245-C02-02 Spain , and the Spanish-Hungarian Binational project TeT ESP-34/2006.Peer reviewe

Kinetics of ventilation-induced changes in diaphragmatic metabolism by bilateral phrenic pacing in a piglet model

Citation: Breuer, T., Hatam, N., Grabiger, B., Marx, G., Behnke, B. J., Weis, J., . . . Bruells, C. S. (2016). Kinetics of ventilation-induced changes in diaphragmatic metabolism by bilateral phrenic pacing in a piglet model. Scientific Reports, 6, 10. doi:10.1038/srep35725Perioperative necessity of deep sedation is inevitably associated with diaphragmatic inactivation. This study investigated 1) the feasibility of a new phrenic nerve stimulation method allowing early diaphragmatic activation even in deep sedation and, 2) metabolic changes within the diaphragm during mechanical ventilation compared to artificial activity. 12 piglets were separated into 2 groups. One group was mechanically ventilated for 12 hrs (CMV) and in the second group both phrenic nerves were stimulated via pacer wires inserted near the phrenic nerves to mimic spontaneous breathing (STIM). Lactate, pyruvate and glucose levels were measured continuously using microdialysis. Oxygen delivery and blood gases were measured during both conditions. Diaphragmatic stimulation generated sufficient tidal volumes in all STIM animals. Diaphragm lactate release increased in CMV transiently whereas in STIM lactate dropped during this same time point (2.6 vs. 0.9 mmol L-1 after 5:20 hrs; p < 0.001). CMV increased diaphragmatic pyruvate (40 vs. 146 mu mol L-1 after 5:20 hrs between CMV and STIM; p < 0.0001), but not the lactate/pyruvate ratio. Diaphragmatic stimulation via regular electrodes is feasible to generate sufficient ventilation, even in deep sedation. Mechanical ventilation alters the metabolic state of the diaphragm, which might be one pathophysiologic origin of ventilator-induced diaphragmatic dysfunction. Occurrence of hypoxia was unlikely

Speckle tracking echography allows sonographic assessment of diaphragmatic loading

Introduction: Assessment of diaphragm function should ideally be assessed using magnetic twitch pressure or esophageal and gastric balloons. Conventional sonographic techniques as thickness and fractional thickening (FT), only provide limited insight in diaphragm function. Speckle tracking echocardiography allows reliable quantification of muscle function by tracking of grey patterns and their motion; strain as parameter of muscle deformation and strain rate as deformation velocity. Aim: To investigate whether speckle tracking can quantify loading of the diaphragm, superior to FT. Methods: 13 healthy volunteers underwent an inspiratory loading protocol with recording of transdiaphragmatic pressure (Pdi) and diaphragm electromyography (EMGdi). Inspiratory loading of 0 to 30% of maximal inspiratory pressure was applied in random order for 5 minutes per applied load. Diaphragmatic sonography was performed using a 2-4 MHz linear phased array transducer positioned at the right-lateral thoracic wall in the anterior axillary line longitudinal to the body axis. Ultrasound recordings of the diaphragm were made at the marked location during 10 seconds. Results: Increased inspiratory loading increased Pdi and EMGdi. Sonographic markers of contractility increased with incremental loading. Pdi correlated with strain (r=0.75; p=0.000) and strain rate (r=0.77; p=0.000). Contrarily, FT was not correlated with Pdi. Conclusion: Speckle tracking of the diaphragm can detect changes in diaphragmatic loading up to 30% of maximal inspiratory pressure. It might be a valuable tool to detect changes in loading in specific patient categories, including patients with acute respiratory failure and ventilated ICU patients

Glanzlichter. Meisterwerke zeitgenössischer Glasmalerei im Naumburger Dom

Glanzlichter. Meisterwerke zeitgenössischer Glasmalerei im Naumburger Dom. 1. Juni bis 2. November 201