Полноволновое двумерное моделирование распространения и поглощения геликонов в плазме сферического токамака Глобус-М2

Numerical modeling of propagation and absorption of fast waves (helicons) with frequency 200 MHz in 2D inhomogeneous plasma of the spherical tokamak Globus-M2 was carried out with 2D full-wave code. Toroidal effects, poloidal magnetic field and the actual shape of the flux surfaces were taken into account. The full wave electric field and RF power absorption profiles were computed by solving plasma wave equation with electron Landau damping term. The modeling demonstrated a fairly high efficiency of helicons absorption in the bulk plasma within a wide range of experimental parameters. The waves propagate to the inner regions of the plasma column and are mainly absorbed there; less than 20% of RF energy returns back to the plasma periphery.

Electroencephalogram Signatures of Agitation Induced by Sevoflurane and Its Association With Genetic Polymorphisms

Background: Volatile anesthetic-induced agitation, also called paradoxical excitation, is not uncommon during anesthesia induction. Clinically, patients with agitation may lead to self-injury or disrupt the operative position, increasing the incidence of perioperative adverse events. The study was designed to investigate clinical features of sevoflurane-induced agitation and examined whether any gene polymorphisms can potentially be used to predict agitation.Methods: One hundred seventy-six patients underwent anesthesia induction with sevoflurane were included in this study. Frontal electroencephalogram (EEG), electromyography (EMG), and hemodynamics were recorded continuously during anesthesia induction. DNA samples were genotyped using the Illumina Infinium Asian Screening Array and the SNaPshot technology. Genetic association was analyzed by genome-wide association study. Logistic regression analysis was used to determine the role of variables in the prediction of agitation.Results: Twenty-five (14.2%) patients experienced agitation. The depth of anesthesia index (Ai index) (p < 0.001), EMG (p < 0.001), heart rate (HR) (p < 0.001), and mean arterial pressure (MAP) (p < 0.001) rapidly increased during the agitation. EEG exhibited a shift toward high frequencies with spikes during agitation. The fast waves (alpha and beta) were more pronounced and the slow rhythms (delta) were less prominent during the occurrence of agitation. Moreover, three SNPs in the methionine synthase reductase (MTRR) gene were correlated to the susceptibility to agitation (p < 5.0 × 10−6). Carrying rs1801394 A > G (odds ratio 3.50, 95% CI 1.43–9.45) and/or rs2307116 G > A (3.31, 1.36–8.95) predicted a higher risk of agitation.Discussion: This study suggests that the agitation/paradoxical excitation induced by sevoflurane is characterized as increases in Ai index, EMG, HR and MAP, and the high frequency with spikes in EEG. Moreover, our results provide preliminary evidence for MTRR genetic polymorphisms, involving folate metabolism function, may be related to the susceptibility to agitation.Clinical Trial Number and Registry URL: ChiCTR1900026218; http://www.chictr.org.cn/showproj.aspx?proj=40655.

ION-CYCLOTRON ABSORPTION OF FAST WAVES IN A CYLINDRICAL CURRENT-CARRYING PLASMA

Influence of a longitudinal stationary current on the absorption and the radial structure of fast waves in a cylindrical current-carrying plasma is discussed. To evaluate the dispersion equation for fast waves, there was used the dielectric tensor taking into account the radial current structure and geometry of the confining helical magnetic field by the plasma safety factor. It is shown that the damping rate of fast waves in a non-equilibrium current-carrying plasma differ from those for an equilibrium plasma column in a homogeneous magnetic field nearby the cutoffs and resonances due to the rotational transformation (including shear-effects) of the helical magnetic field lines.

Vagal nerve stimulation is effective in pre-school children with intractable epilepsy: A report of two cases

There is lack of prospective evidence regarding vagal nerve stimulator (VNS) in younger children with intractable epilepsy. Here, we report the outcomes of using VNS in two pre-school patients for pediatric intractable epilepsy (VNS-PIE) study. Medical treatment was ineffective in both the patients, and they underwent VNS implantation. Seizure frequency, score on the Gesell scale, and heart rate variability (HRV) were assessed following VNS therapy. After 6 months VNS treatment, the seizure frequency in the two patients decreased by 50% from that at baseline, based on the records in their epileptic diary. Video electroencephalography (EEG) examinations showed that abnormal fast waves diminished in the background in Patient 1, and captured seizure frequency in Patient 2 remarkably decreased. The adaptability, language, and individual and social interaction on their Gesell scales increased slightly, suggesting that VNS had a positive effect on the development of these two children. Moreover, the changes in the different HRV indices indicated improved cardiac autonomic function. In conclusion, these two cases indicated that VNS may not only be a superior therapy for pre-school children with intractable epilepsy, but also may exert a positive effect on their mental development and cardiac autonomic function.

Scale Analysis of Moist Thermodynamics in a Simple Model and the Relationship between Moisture Modes and Gravity Waves

Observations and theory of convectively coupled equatorial waves suggest that they can be categorized into two distinct groups. Moisture modes are waves whose thermodynamics are governed by moisture fluctuations. The thermodynamics of the gravity wave group, on the other hand, are rooted in buoyancy (temperature) fluctuations. On the basis of scale analysis, it is found that a simple nondimensional parameter—akin to the Rossby number—can explain the processes that lead to the existence of these two groups. This parameter, defined as Nmode, indicates that moisture modes arise when anomalous convection lasts sufficiently long so that dry gravity waves eliminate the temperature anomalies in the convective region, satisfying weak temperature gradient (WTG) balance. This process causes moisture anomalies to dominate the distribution of moist enthalpy (or moist static energy), and hence the evolution of the wave. Conversely, convectively coupled gravity waves arise when anomalous convection eliminates the moisture anomalies more rapidly than dry gravity waves can adjust the troposphere toward WTG balance, causing temperature to govern the moist enthalpy distribution and evolution. Spectral analysis of reanalysis data indicates that slowly propagating waves (cp ~ 3 m s−1) are likely to be moisture modes while fast waves (cp ~ 30 m s−1) exhibit gravity wave behavior, with “mixed moisture–gravity” waves existing in between. While these findings are obtained from a highly idealized framework, it is hypothesized that they can be extended to understand simulations of convectively coupled waves in GCMs and the thermodynamics of more complex phenomena.