Very‐low‐energy diets (VLEDs) and ketogenic low‐carbohydrate diets (KLCDs) are two dietary strategies that have been associated with a suppression of appetite. However, the results of clinical trials ...investigating the effect of ketogenic diets on appetite are inconsistent. To evaluate quantitatively the effect of ketogenic diets on subjective appetite ratings, we conducted a systematic literature search and meta‐analysis of studies that assessed appetite with visual analogue scales before (in energy balance) and during (while in ketosis) adherence to VLED or KLCD. Individuals were less hungry and exhibited greater fullness/satiety while adhering to VLED, and individuals adhering to KLCD were less hungry and had a reduced desire to eat. Although these absolute changes in appetite were small, they occurred within the context of energy restriction, which is known to increase appetite in obese people. Thus, the clinical benefit of a ketogenic diet is in preventing an increase in appetite, despite weight loss, although individuals may indeed feel slightly less hungry (or more full or satisfied). Ketosis appears to provide a plausible explanation for this suppression of appetite. Future studies should investigate the minimum level of ketosis required to achieve appetite suppression during ketogenic weight loss diets, as this could enable inclusion of a greater variety of healthy carbohydrate‐containing foods into the diet.
The paper evaluates the impact of metallic structures of the COMPASS-U tokamak design on signals measured by in-vessel magnetic diagnostic coils. The eddy current shielding caused by the tokamak ...conductive structures of the vacuum vessel and plasma facing components is evaluated using finite element analysis performed by ANSYS Maxwell software. The simulation of the sudden shifts in the radial or vertical position of the plasma column returns 33–45% amplification of the tangential field component that from the most part would be analogous to a simple lumped circuit model approximation, despite the complex 3D shape of the nearby plasma facing components. The simulation of a rotating helical filament close to plasma edge (approximating a rotating magnetic island magnetohydrodynamic (MHD) structure) reveals an unexpected spatial modulation of the magnitude attenuation coefficient of up to 45% for the tangential field component across different positions relative to the PFC holders. Both results have led to the described conclusions for the sensor positioning design, specifically to the decision to install plasma position feedback sensors in between the robust holders of the PFC tiles, and the plasma MHD activity sensors strictly symmetrically with respect to these PFC structures.
Abstract Background Hypoglycaemia in CF in the absence of diabetes or glucose lowering therapies is a phenomenon that is receiving growing attention in the literature. These episodes are sometimes ...symptomatic and likely have variable aetiologies. Our first aim was to conduct a systematic review of the literature to determine what is known about hypoglycaemia in CF. Our second aim was to assess evidence based guidelines for management strategies. Methods A comprehensive search of databases and guideline compiler entities was performed. Inclusion criteria were primary research articles and evidence based guidelines that referred to hypoglycaemia in CF in the absence of insulin treatment or other glucose lowering therapies. Results A total of 11 studies (four manuscripts and seven abstracts) and five evidence-based guidelines met the inclusion criteria. Prevalence rates of hypoglycaemia unrelated to diabetes varied between studies (7–69%). Hypoglycaemia was diagnosed during oral glucose tolerance testing or continuous glucose monitoring (CGM). Associations between hypoglycaemia and clinical parameters of BMI, lung function, liver disease and pancreatic insufficiency were measured in some studies. There was no unifying definition of hypoglycaemia in the absence of diabetes. Only two evidence based guidelines reported possible management strategies. Conclusion The systematic review found limited data on this clinical problem and supports the need for high quality methodological studies that are able to describe the experience and the aetiology(ies) of hypoglycaemia in CF.
•High magnetic field and high plasma density tokamak with SOL decay length close to ITER and PB/qAR ratio 70% of ITER.•Closed divertor that allows snowflake divertor configuration.•Ohmic losses in ...magnets reduced via cryogenic cooling of Cu coils to liquid nitrogen temperatures.•Operation of the first wall at 300°C.•Auxiliary plasma heating systems: 4MW NBI with variable injection geometry, 4MW ECRH using ITER-like gyrotrons.
The paper describes the conceptual design of the COMPASS Upgrade (COMPASS-U) tokamak which represents a compact, medium-size, high-magnetic-field and high-density device with a flexible set of poloidal field coils for generation of single, double null and snowflake configurations. In addition, COMPASS-U will be equipped with a closed divertor, which will be operated at high plasma and neutral density and with high optical opacity similar to future reactors. COMPASS-U is capable of addressing some of the key challenges in the field of the plasma exhaust physics, reactor-relevant edge plasma physics, advanced confinement regimes, advanced magnetic configurations and materials for next-step devices. The conceptual design of the individual COMPASS-U systems is presented with emphasis on magnets, support structure and power supply system enhancement.
•Large multi-device database used for exploratory study of MHD disruption precursors•Dependencies of MHD mode time scales were studied•New scaling law for duration of mode locking phase reveals ...increasing trend with plasma size•Scaling for disruptive mode amplitude (de Vries 2016) validated using new database
Disruptions in tokamaks are often preceded by magnetohydrodynamic (MHD) instabilities that can rotate or become locked to the wall. Measurements from magnetic diagnostics in the presence of MHD mode precursors to disruptions can yield potentially valuable input to the plasma control system, with a view to disruption avoidance, prediction and mitigation. This paper presents an exploratory analysis of the growth of MHD modes and corresponding time scales on the basis of magnetic measurements in multiple tokamaks. To this end, a database was compiled using disruptive discharges from COMPASS, ASDEX Upgrade, DIII-D and JET, manually classified according to disruption root cause, and characterized by a great diversity of operational conditions and mode dynamics. The typical time during which a mode can be detected using saddle coils and the duration of the locked mode phase in the database both extend over several orders of magnitude, but generally the time scales increase with plasma size. Several additional factors are discussed that can influence these durations, including the disruption root cause. A scaling law for the locked phase duration was estimated, yielding predictions toward ITER of the order of hundreds of milliseconds or even seconds. In addition, a scaling law for the mode amplitude at the disruption onset, proposed earlier by de Vries et al. (2016), is applied to the database, and its predictive capabilities are assessed. Despite significant uncertainty on the predictions from both scaling laws, encouraging trends are observed of the fraction of disruptions that may be detected with sufficient warning time to allow mitigation or even avoidance, based solely on observations of MHD mode dynamics. When combined with similar analysis of measurements from diagnostics that are sensitive to other disruption precursors, our analysis methods and results may contribute to the reliability, robustness and generalization of disruption warning schemes for ITER.
Disruption-generated runaway electron (RE) beams represent a potentially severe threat for tokamak plasma-facing components. Application of properly designed 3D fields can act as a mitigation ...mechanism, as recently investigated in ASDEX Upgrade (AUG) and COMPASS experiments and in the tokamak discharges of RFX-mod. In all of these devices, the dynamics of the disruption are affected by the application of magnetic perturbations (MPs), and the resulting RE beam current and lifetime are significantly reduced. These experiments show, in particular, that the strength of the observed effects strongly depends on the poloidal spectrum of the applied MPs, which has been reconstructed including the plasma response. This paper reports the main findings on RE mitigation from the previously mentioned three devices, highlighting the common physics behind them and their interpretation by using the guiding center code ORBIT.
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