Dynamics of a few corotating vortices in Bose-Einstein condensates

We study the dynamics of small vortex clusters with a few (2-4) corotating vortices in Bose-Einstein condensates by means of experiments, numerical computations, and theoretical analysis. All of these approaches corroborate the counterintuitive presence of a dynamical instability of symmetric vortex configurations. The instability arises as a pitchfork bifurcation at sufficiently large values of the vortex system angular momentum that induces the emergence and stabilization of asymmetric rotating vortex configurations. The latter are quantified in the theoretical model and observed in the experiments. The dynamics is explored both for the integrable two-vortex particle system, where a reduction of the phase space of the system provides valuable insight, as well as for the nonintegrable three- (or more) vortex case, which additionally admits the possibility of chaotic trajectories.

[Description of the hemodynamic and respiratory effects of hemoperfusion treatment with polymyxin B in patients with abdominal septic shock]

The objective of this study is to describe the hemodynamic effects, inotropic and vasoactive drug dependence, and to analyze the PO2/FiO2 ratio in 13 patients with septic shock of abdominal origin after hemoperfusion treatment with polymyxin-B. Treatment with polymyxin hemoperfusion therapy is indicated for patients with severe sepsis/septic shock of abdominal origin who do not respond adequately to conventional therapy. Two complete cycles with polymyxin cartridge were performed on 11 of the 13 patients, and a single cycle on the other O2. After treatment, the mean airway pressure (MAP) was increased (P=.003), the need for norepinephrine decreased (P=.003), and the PO2/FiO2 ratio increased (P=.02). The use of polymyxin hemoperfusion in patients with septic shock of intra-abdominal origin can significantly improve hemodynamic and respiratory functions.

Measurement of total water and bound water contents in human stratum corneum by in vitro proton nuclear magnetic resonance spectroscopy

The reliability of in vitro proton nuclear magnetic resonance (NMR) spectroscopy to specifically measure the water content of rehydrated human stratum corneum samples was assessed by comparison with the previously validated thermal desorption-mass spectrometry technique. The interest of proton NMR is that it can determine, in the same sample, both the amount of total water by recording the spectra at ambient temperature, and that of bound water (non-freezing water) by recording the spectra below 0 degrees C. Provided that enough samples of stratum corneum are analysed to average out the observed and well-known sample-to-sample variation, proton NMR may be of value in the evaluation of hygroscopic properties of raw materials for moisturizer formulations.

Gastric emptying is delayed in transgastric NOTES: a randomized study in swine

AIM

The aim of this study was to evaluate the restoration of gastrointestinal motility after NOTES using capsule endoscopy (CE).

MATERIALS AND METHODS

Twenty adult Yorkshire pigs were randomly assigned to four groups: transgastric NOTES (gNOTES), transrectal NOTES (rNOTES), transvaginal NOTES (vNOTES), and laparoscopy (LAP). At the end of a 30-min peritoneoscopy with identification of seven predetermined organs, an array of eight receivers and the recorder were attached to the abdominal wall. The CE was delivered into the antrum with the help of an endoscope and a polypectomy snare. Animals were kept alive for 14 d.

RESULTS

Median time for surgery was longer in gNOTES (56 min, range 47-63) and vNOTES (54 min, range 44-79) than in LAP (32 min, range 32-33; P < 0.05 and P < 0.01) and in rNOTES (45.5 min, range 33-56) (P = ns). This increase was related to a larger incision and longer closure times. Images from the CE were successfully retrieved in 19 cases. The CE was retained in the stomach in all animals in gNOTES (459 min; range 360-600), but only in one animal in rNOTES and vNOTES and in none in the LAP group. Failure of passage of the CE beyond the stomach was associated with gNOTES and longer closure of the incision. Animals in the gNOTES group gained less weight than the others and this change was statistical significant when compared with vNOTES animals (1.7 kg, range -1.98 to 4.5 versus 8.4 kg, range 5.8 to 11.45; P < 0.01).

CONCLUSION

Gastric emptying is delayed after gNOTES peritoneoscopy compared with rNOTES, vNOTES, and LAP and this effect is associated with less weight gain.

Coalescence cascade of dissipative solitons in parametrically driven systems

Parametrically driven spatially extended systems exhibit uniform oscillations which are modulationally unstable. The resulting periodic state evolves to the creation of a gas of dissipative solitons. Driven by the interaction of dissipative solitons, the multisoliton state undergoes a cascade of coalescence processes, where the average soliton separation distance obeys a temporal self-similar law. Starting from the soliton pair interaction law, we have derived analytically and characterized the law of this multisoliton coarsening process. A comparison of numerical results obtained with different models such as the parametrically driven damped nonlinear Schrödinger equation, a vertically driven chain of pendula, and a parametrically forced magnetic wire, shows remarkable agreement. Both phenomena, the pair interaction law and the coarsening process, are also observed experimentally in a quasi-one-dimensional layer of Newtonian fluid which is oscillated vertically.

Toxicity and neuropharmacological effects of elenine

Elenine is the aglycone of elenoside, a cytotoxic arylnaphthalene lignan (NSC 644013-W/1) derived from Justicia hyssopifolia. (Family: Acanthaceae). Elenoside is a β-D-glucoside, with a similar chemical structure to etoposide, exhibiting central depressant activity. In the present study, elenine was given to mice and rats at doses of 10, 20, and 40 mg/kg. Acute toxicity (24 h) and general behaviour in mice was studied as well as its effects on muscular relaxant activity, locomotor activity (Varimex test), and the open-field test and were compared with 10 mg/kg of chlorpromazine. Elenine produced a reduction in the permanence time in muscular relaxant activity (traction test). Spontaneous activity was lower in the Varimex test. The ambulation and rearing were lower compared with the control group, and an increase in boluses was observed in the open-field test. Thus, it can be concluded that elenine has central sedative effects at lower doses than those used with elenoside and has a possible application in conditions of anxiety.

The role of a computed tomography-based image registered navigation system for natural orifice transluminal endoscopic surgery: a comparative study in a porcine model

BACKGROUND AND STUDY AIMS

Most natural orifice transluminal endoscopic surgery (NOTES) procedures have been performed in animal models through the anterior stomach wall, but this approach does not provide efficient access to all anatomic areas of interest. Moreover, injury of the adjacent structures has been reported when using a blind access. The aim of the current study was to assess the utility of a CT-based (CT: computed tomography) image registered navigation system in identifying safe gastrointestinal access sites for NOTES and identifying intraperitoneal structures.

METHODS

A total of 30 access procedures were performed in 30 pigs: anterior gastric wall (n = 10), posterior gastric wall (n = 10), and anterior rectal wall (n = 10). Of these, 15 procedures used image registered guidance (IR-NOTES) and 15 procedures used a blind access (NOTES only). Timed abdominal exploration was performed with identification of 11 organs. The location of the endoscopic tip was tracked using an electromagnetic tracking system and was recorded for each case. Necropsy was performed immediately after the procedure. The primary outcome was the rate of complications; secondary outcome variables were number of organs identified and kinematic measurements.

RESULTS

A total of 30 animals weighting a mean (± SD) of 30.2 ± 6.8 kg were included in the study. The incision point was correctly placed in 11 out of 15 animals in each group (73.3 %). The mean peritoneoscopy time and the number of properly identified organs were equivalent in the two groups. There were eight minor complications (26.7 %), two (13.3 %) in the IR-NOTES group and six (40.0 %) in the NOTES only group ( P = n. s.). Characteristics of the endoscope tip path showed a statistically significant improvement in trajectory smoothness of motion for all organs in the IR-NOTES group.

CONCLUSION

The image registered system appears to be feasible in NOTES procedures and results from this study suggest that image registered guidance might be useful for supporting navigation with an increased smoothness of motion.

Yes, we can: reliable colonic closure with the Padlock-G clip in a survival porcine study (with video)

BACKGROUND

Secure closure of the colonic access site is one of the most important issues for the development of natural orifice transluminal endoscopic surgery.

OBJECTIVE

To evaluate the feasibility, reproducibility, and efficacy of a new over-the-scope clip.

DESIGN

Descriptive study, in vivo porcine colon.

INTERVENTION

In 10 female Yorkshire pigs weighing 30 to 35 kg, a 10-mm colotomy was performed by using a needle-knife and advancing the endoscope to the peritoneal cavity. Colonic closure was performed by using the Padlock-G clip (Aponos Medical, Kingston, NH) delivered with the Lock-It system (Aponos).

MAIN OUTCOME MEASUREMENTS

Animals were monitored daily for signs of peritonitis and sepsis over a period of 14 days. During necropsy, the peritoneal cavity was examined, and the colon segment containing the incision was excised for pathological study.

RESULTS

Closure was achieved in all cases. Nine of 10 pigs survived 14 days without complications, but 1 pig was killed immediately after the procedure because of severe bleeding during the colonic incision. The median closure time was 8 minutes (range 1-30 minutes). At necropsy, adhesions were observed in 5 cases. The incision was hardly visible at the serosa side in 3 cases and was not identified in 6 cases. In 6 cases, the clip was still slightly attached to the mucosa, and it was not found in 3 cases. The pathological study revealed a complete remodeling of the colonic wall in all cases.

LIMITATIONS

Animal model, noncomparative study.

CONCLUSION

The Padlock-G clip procedure is feasible, reproducible, effective, and easy to perform, and it provides a reliable colonic closure.