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

Electrocautery causes more ischemic peritoneal tissue damage than ultrasonic dissection

Contains fulltext : 96869.pdf (publisher's version ) (Open Access)BACKGROUND: Minimizing peritoneal tissue injury during abdominal surgery has the benefit of reducing postoperative inflammatory response, pain, and adhesion formation. Ultrasonic dissection seems to reduce tissue damage. This study aimed to compare electrocautery and ultrasonic dissection in terms of peritoneal tissue ischemia measured by microdialysis. METHODS: In this study, 18 Wistar rats underwent a median laparotomy and had a peritoneal microdialysis catheter implanted in the left lateral sidewall. The animals were randomly assigned to receive two standard peritoneal incisions parallel to the catheter by either ultrasonic dissection or electrocautery. After the operation, samples of microdialysis dialysate were taken every 2 h until 72 h postoperatively for measurements of pyruvate, lactate, glucose, and glycerol, and ratios were calculated. RESULTS: The mean lactate-pyruvate ratio (LPR), lactate-glucose ratio (LGR), and glycerol concentration were significantly higher in the electrocautery group than in the ultrasonic dissection group until respectively 34, 48, and 48 h after surgery. The mean areas under the curve (AUC) of LPR, LGR, and glycerol concentration also were higher in the electrocautery group than in the ultrasonic dissection group (4,387 vs. 1,639, P=0.011; 59 vs. 21, P=0.008; 7,438 vs. 4,169, P=0.008, respectively). CONCLUSION: Electrosurgery causes more ischemic peritoneal tissue damage than ultrasonic dissection.01 juni 201

The use of the Airtraq® optical laryngoscope for routine tracheal intubation in high-risk cardio-surgical patients

<p>Abstract</p> <p>Background</p> <p>The Airtraq^®optical laryngoscope (Prodol Ltd., Vizcaya, Spain) is a novel disposable device facilitating tracheal intubation in routine and difficult airway patients. No data investigating routine tracheal intubation using the Airtaq^®in patients at a high cardiac risk are available at present. Purpose of this study was to investigate the feasibility and hemodynamic implications of tracheal intubation with the Aitraq^®optical laryngoscope, in high-risk cardio-surgical patients.</p> <p>Methods</p> <p>123 consecutive ASA III patients undergoing elective coronary artery bypass grafting were routinely intubated with the Airtraq^®laryngoscope. Induction of anesthesia was standardized according to our institutional protocol. All tracheal intubations were performed by six anesthetists trained in the use of the Airtraq^®prior.</p> <p>Results</p> <p>Overall success rate was 100% (n = 123). All but five patients trachea could be intubated in the first attempt (95,9%). 5 patients were intubated in a 2nd (n = 4) or 3rd (n = 1) attempt. Mean intubation time was 24.3 s (range 16-128 s). Heart rate, arterial blood pressure and SpO₂were not significantly altered. Minor complications were observed in 6 patients (4,8%), i.e. two lesions of the lips and four minor superficial mucosal bleedings. Intubation duration (p = 0.62) and number of attempts (p = 0.26) were independent from BMI and Mallampati score.</p> <p>Conclusion</p> <p>Tracheal intubation with the Airtraq^®optical laryngoscope was feasible, save and easy to perform in high-risk patients undergoing cardiac surgery. In all patients, a sufficient view on the vocal cords could be obtained, independent from BMI and preoperative Mallampati score.</p> <p>Trial Registration</p> <p>DRKS 00003230</p

Effects of feeding a standard diet on duodenal impedancometry in pigs

The effects of gastric feeding on intestinal motility are still under debate. In order to better define the character of the contractile activity in fed and fasting states, we used the impedance technique to investigate the duodenal time periods of the migrating motor complex (MMC) and the interdigestive phases I-III. During general anaesthesia, pigs (32-40 kg) were instrumented with a luminal impedance catheter into the proximal duodenum in fasting (n = 6) and fed states (n = 6, Muskator®, 400 g, Muskator-Werk, Düsseldorf, Germany). Duodenal motility was recorded continuously for 4 h, which made it possible to determine the length of interdigestive phases I-III and the MMC cycle. Differences between the groups were compared by using the Wilcoxon Rank-Sum Test. Feeding patterns were only found in pigs in the fed state. The subsequent MMC cycle length was shortened by 34% (p = 0.007) which was due to a shortened phase I of the MMC cycle (p = 0.014). While phase II seemed to be unaffected, phase III was prolonged by 31% after feeding had occurred (p = 0.012). The present study suggests that a standard maintenance diet disrupts the spontaneous MMC cycles by turning into fed pattern with the subsequent MMC cycle length being shortened. This was mainly due to a shortened phase I