Non-Thermal Solar Wind Electron Velocity Distribution Function.

The quiet-time solar wind electrons feature non-thermal characteristics when viewed from the perspective of their velocity distribution functions. They typically have an appearance of being composed of a denser thermal "core" population plus a tenuous energetic "halo" population. At first, such a feature was empirically fitted with the kappa velocity space distribution function, but ever since the ground-breaking work by Tsallis, the space physics community has embraced the potential implication of the kappa distribution as reflecting the non-extensive nature of the space plasma. From the viewpoint of microscopic plasma theory, the formation of the non-thermal electron velocity distribution function can be interpreted in terms of the plasma being in a state of turbulent quasi-equilibrium. Such a finding brings forth the possible existence of a profound inter-relationship between the non-extensive statistical state and the turbulent quasi-equilibrium state. The present paper further develops the idea of solar wind electrons being in the turbulent equilibrium, but, unlike the previous model, which involves the electrostatic turbulence near the plasma oscillation frequency (i.e., Langmuir turbulence), the present paper considers the impact of transverse electromagnetic turbulence, particularly, the turbulence in the whistler-mode frequency range. It is found that the coupling of spontaneously emitted thermal fluctuations and the background turbulence leads to the formation of a non-thermal electron velocity distribution function of the type observed in the solar wind during quiet times. This demonstrates that the whistler-range turbulence represents an alternative mechanism for producing the kappa-like non-thermal distribution, especially close to the Sun and in the near-Earth space environment.

Self-modulation of nonlinear Alfvén waves in a strongly magnetized relativistic electron-positron plasma.

We study the self-modulation of a circularly polarized Alfvén wave in a strongly magnetized relativistic electron-positron plasma with finite temperature. This nonlinear wave corresponds to an exact solution of the equations, with a dispersion relation that has two branches. For a large magnetic field, the Alfvén branch has two different zones, which we call the normal dispersion zone (where dω/dk>0) and the anomalous dispersion zone (where dω/dk<0). A nonlinear Schrödinger equation is derived in the normal dispersion zone of the Alfvén wave, where the wave envelope can evolve as a periodic wave train or as a solitary wave, depending on the initial condition. The maximum growth rate of the modulational instability decreases as the temperature is increased. We also study the Alfvén wave propagation in the anomalous dispersion zone, where a nonlinear wave equation is obtained. However, in this zone the wave envelope can evolve only as a periodic wave train.

Dexamethasone for postoperative nausea and vomiting prophylaxis: effect on glycaemia in obese patients with impaired glucose tolerance.

BACKGROUND AND OBJECTIVE: Dexamethasone given to prevent postoperative nausea and vomiting may produce significant hyperglycaemia in the perioperative period. The effect of dexamethasone on patients with impaired glucose tolerance is unknown. METHODS: Thirty obese patients with impaired glucose tolerance undergoing laparoscopic Roux-en-Y gastric bypass surgery were studied in a double-blind fashion. Patients were randomly distributed into two groups: the dexamethasone group (n = 15) received dexamethasone 8 mg intravenously after induction of anaesthesia; the control group (n = 15) received isotonic saline. Fingerprick capillary blood glucose concentrations were measured at baseline and every 2 h during the first 12 h after the start of surgery. RESULTS: In both groups, all blood glucose concentrations measured after the beginning of surgery were higher than baseline values. However, the dexamethasone group showed higher glucose concentrations than the control group from the 6th to the 12th hour of the study. In addition, the maximum blood glucose value in the dexamethasone group (10.4 +/- 1.6 mmol l(-1)) was higher than in the controls (8.8 +/- 1.7 mmol l(-1)) (P < 0.05). CONCLUSION: Dexamethasone, 8 mg, intravenously administered at the beginning of laparoscopic bariatric surgery in patients with impaired glucose tolerance is associated with significantly increased postoperative blood glucose concentrations.

Elaboration and structural analysis of aquasomes loaded with indomethacin.

The aim of this study was to prepare nanoparticles in form of aquasomes with Indomethacin as a low solubility drug mode. Aquasomes charged with Indomethacin were obtained through the formation of an inorganic core of calcium phosphate covered with a Lactose film and further adsorption of the Indomethacin. Structural analyses, particle size, and morphology were evaluated by X-ray powder diffractometry, transmission electron microscopy, and scanning electron microscopy. The X-ray analysis of the samples and their observation through electronic microscopy allowed us to identify the inorganic calcium phosphate nucleus formation, as well as the layers of Lactose and Indomethacin. The particle size analysis of the aquasomes obtained with the Lactose layer and charged with the drug indicated an average particle size in the range of 60-120 nm, with a media of 90 nm. Standard deviation was 18.0234 and the standard error of the media 4.1348. The method was reproducible under the conditions used to prepare the aquasomes, such as ultrasound frequency and the moment of sonication for the formation of inorganic cores.