Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection

A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)

Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

On the toxicity of dimethylcyanamide (Russian)

Dimethylcyanamide (DMC) is a highly poisonous compound with diverse modes of its introduction into the organism. For mice (with gastric introduction) LD50 = 73 mg/kg; for rats and guinea pigs it amounts to 146; for mice LD50 (skin) is 125 mg/kg. For mice LC50 is 2800 mg/m3, for rats 2500 mg/m3. Lim(ac) for mice and rats is 100 mg/m3. The compound displays a very poorly marked functional cumulation. The mechanism of its action is analogous to that of inorganic cyanamides. As a tentatively safe level of action a concentration of 0.5 mg/m3 is recommended

On the toxicity of dimethylcyanamide (Russian)

Dimethylcyanamide (DMC) is a highly poisonous compound with diverse modes of its introduction into the organism. For mice (with gastric introduction) LD50 = 73 mg/kg; for rats and guinea pigs it amounts to 146; for mice LD50 (skin) is 125 mg/kg. For mice LC50 is 2800 mg/m3, for rats 2500 mg/m3. Lim(ac) for mice and rats is 100 mg/m3. The compound displays a very poorly marked functional cumulation. The mechanism of its action is analogous to that of inorganic cyanamides. As a tentatively safe level of action a concentration of 0.5 mg/m3 is recommended

Post-COVID syndrome in children and adolescents: a literature review and clinical case

L.A. Balykova, M.V. Shirmankina, D.O. Vladimirov, E.I. Naumenko, E.S. Samoshkina, R.A. Chernyshova N.P. Ogarev Mordovia State University, Saransk, Russian Federation Post-COVID-19 syndrome is an important challenge for modern medicine, requiring the involvement of different health professionals. This multidisciplinary approach is underpinned by the variety of clinical manifestations and the need for comprehensive rehabilitation of patients, including children and adolescents. The review highlights clinical manifestations of post-COVID-19 syndrome. Currently, a symptom management approach has been established for improving post-COVID-19 conditions. Also, appropriate lifestyle changes, such as adequate rest and sleep hygiene, may be useful. Rehabilitation interventions for post-COVID-19 syndrome may include physiotherapy exercises and various psychotherapy techniques. Since mitochondrial dysfunction, energy supply deficit, oxidative stress, endothelial dysfunction, and immune dysregulation profoundly impact the pathogenesis of post-COVID-19 syndrome, the use of L-carnitine which plays a crucial role in energy production, is consider ed as a promising method in the management of such patients. L-carnitine may have cardioprotective, anabolic and neuroprotective effects. The authors present a case report of post-COVID-19 condition in their own patient, a 4-year-old boy who survived multisystem inflammatory syndrome. As a result of combination therapy, including L-carnitine, the patient’s sense of well-being significantly improved: he had no complaints, the muscle weakness and asthenization became less pronounced, and his spirits rose. The described clinical case illustrated the effectiveness of using L-carnitine in the combined therapy of post-COVID-19 syndrome in children. Keywords: COVID-19, post-COVID syndrome, multisystem inflammatory syndrome, L-carnitine, children, rehabilitation, asthenization, anxiety disorder. For citation: Balykova L.A., Shirmankina M.V., Vladimirov D.O. et al. Post-COVID syndrome in children and adolescents: a literature review and clinical case. Russian Journal of Woman and Child Health. 2022;5(4):366–372 (in Russ.). DOI: 10.32364/2618-8430-2022-5-4-366-372. <br

Impact of nitrogen seeding on confinement and power load control of a high-triangularity JET ELMy H-mode plasma with a metal wall

This paper reports the impact on confinement and power load of the high-shape 2.5MA ELMy H-mode scenario at JET of a change from an all carbon plasma facing components to an all metal wall. In preparation to this change, systematic studies of power load reduction and impact on confinement as a result of fuelling in combination with nitrogen seeding were carried out in JET-C and are compared to their counterpart in JET with a metallic wall. An unexpected and significant change is reported on the decrease of the pedestal confinement but is partially recovered with the injection of nitrogen.Comment: 30 pages, 16 figure

X-ray crystal spectrometer upgrade for ITER-like wall experiments at JET

The high resolution X-Ray crystal spectrometer at the JET tokamak has been upgraded with the main goal of measuring the tungsten impurity concentration. This is important for understanding impurity accumulation in the plasma after installation of the JET ITER-like wall (main chamber: Be, divertor: W). This contribution provides details of the upgraded spectrometer with a focus on the aspects important for spectral analysis and plasma parameter calculation. In particular, we describe the determination of the spectrometer sensitivity: important for impurity concentration determination