Physics research on the TCV tokamak facility: from conventional to alternative scenarios and beyond

The research program of the TCV tokamak ranges from conventional to advanced-tokamak scenarios and alternative divertor configurations, to exploratory plasmas driven by theoretical insight, exploiting the device’s unique shaping capabilities. Disruption avoidance by real-time locked mode prevention or unlocking with electron-cyclotron resonance heating (ECRH) was thoroughly documented, using magnetic and radiation triggers. Runaway generation with high-Z noble-gas injection and runaway dissipation by subsequent Ne or Ar injection were studied for model validation. The new 1 MW neutral beam injector has expanded the parameter range, now encompassing ELMy H-modes in an ITER-like shape and nearly non-inductive H-mode discharges sustained by electron cyclotron and neutral beam current drive. In the H-mode, the pedestal pressure increases modestly with nitrogen seeding while fueling moves the density pedestal outwards, but the plasma stored energy is largely uncorrelated to either seeding or fueling. High fueling at high triangularity is key to accessing the attractive small edge-localized mode (type-II) regime. Turbulence is reduced in the core at negative triangularity, consistent with increased confinement and in accord with global gyrokinetic simulations. The geodesic acoustic mode, possibly coupled with avalanche events, has been linked with particle flow to the wall in diverted plasmas. Detachment, scrape-off layer transport, and turbulence were studied in L- and H-modes in both standard and alternative configurations (snowflake, super-X, and beyond). The detachment process is caused by power ‘starvation’ reducing the ionization source, with volume recombination playing only a minor role. Partial detachment in the H-mode is obtained with impurity seeding and has shown little dependence on flux expansion in standard single-null geometry. In the attached L-mode phase, increasing the outer connection length reduces the in–out heat-flow asymmetry. A doublet plasma, featuring an internal X-point, was achieved successfully, and a transport barrier was observed in the mantle just outside the internal separatrix. In the near future variable-configuration baffles and possibly divertor pumping will be introduced to investigate the effect of divertor closure on exhaust and performance, and 3.5 MW ECRH and 1 MW neutral beam injection heating will be added

First-time complete visualization of a preserved meningeal artery in the mummy of Nakht-ta-Netjeret (ca. 950 BC)

The preservation of the meningeal artery in ancient mummified bodies, particularly in anthropogenic Egyptian mummies, is a highly controversial topic in neuroscience and anthropological research. A recent (2015) debate between Wade and Isidro, based on the interpretation of the meningeal grooves and cast in a skull from the necropolis of Kom al-Ahmar Sharuna (Egypt), highlighted both the necessity of having clear radiological descriptions of this anatomical structure and of assessing large collections of mummified crania. Here, we present for the first time an instance of extremely well-preserved middle meningeal artery in the mummy of the ancient Egyptian dignitary Nakht-ta-Netjeret (ca. 950 BC), still inside the meninx, using paleo-radiological techniques. We finally link this find with experimental data from the neurological literature on the methodology of excerebration implemented by ancient Egyptian embalmers.Roger Seiler, Michael E. Habicht, Frank J. Rühli, Francesco M. Galass

Computation of Distorted Wave Cross Sections for High-Energy Inelastic Collisions of Heavy Ions with Water Molecules

Irradiation of water and other molecules of biological interest by heavy ion beams is studied. Distorted wave models are employed to investigate the corresponding inelastic collisions. Cross sections for electronic capture, ionization, and excitation processes are determined as well as equilibrium charge-states and electronic stopping power. The influence of multiple ionization in liquid water radiolysis is analyzed

Theoretical multiple-ionization cross sections of Ne-like molecules by light-ion impact: <math><mrow><msub><mi mathvariant="normal">H</mi><mn>2</mn></msub><mi mathvariant="normal">O</mi></mrow></math>

International audienceWe present a simple theoretical model to calculate multiple-ionization cross sections (MICS) of Ne and Ne-like molecules (molecules with ten electrons as H2O, CH4, NH3, and HF) for proton and light-ion impact, taking into account both direct and postcollisional emissions. In this paper, we tackle the case of water molecules, relevant to investigate the radiobiological effects of ion impact on living matter. The theory is developed in the framework of the independent electron model (IEM). To keep the model as simple as possible, we describe the impact parameter dependence of the single-particle ionization probabilities required by the IEM through decreasing exponential functions for each target orbital. We obtain the parameters of the exponential functions from the total net-ionization cross sections for each orbital by applying either the continuum distorted wave-eikonal initial-state (CDW-EIS) approximation or Rudd's model. We then calculate the contribution of Auger postcollisional electron emission to MICS by using the Ne postcollisional emission probabilities. This postcollisional treatment offers a very simple alternative to the much more complex molecular evaluation of postcollisional relaxation and provides results in close agreement with experimental data for proton and other light ions. We also demonstrate the relevance of considering postcollisional emission for water molecules after the 2a1 (2s Ne-like) orbital direct ionization

Uric Acid in chronic kidney disease : a clinical appraisal

A consistent body of evidence supports an independent association between uric acid (UA) level and the risk of chronic kidney disease (CKD) in humans. It has been observed in experimental data that UA is capable of inducing renal damage through several pathways, including activation of the renin-angiotensinaldosterone system (RAAS), oxidative stress, and inflammation. Treatment with urate lowering agents and RAAS inhibitors prevented renal insult mediated by UA in animal models. Both of the xanthine oxidase inhibitors available in clinical practice, allopurinol and febuxostat, were efficient in controlling gout flares. However, data from randomised controlled trials are still inconsistent in relation to their benefit for slowing CKD progression. This review discusses the metabolism of urates in humans as well as the experimental and clinical evidence linking UA to CKD. Current evidence about the effect of allopurinol and febuxostat on CKD progression is also considered