Overview of progress in European medium sized tokamaks towards an integrated plasma-edge/wall solution

Integrating the plasma core performance with an edge and scrape-off layer (SOL) that leads to tolerable heat and particle loads on the wall is a major challenge. The new European medium size tokamak task force (EU-MST) coordinates research on ASDEX Upgrade (AUG), MAST and TCV. This multi-machine approach within EU-MST, covering a wide parameter range, is instrumental to progress in the field, as ITER and DEMO core/pedestal and SOL parameters are not achievable simultaneously in present day devices. A two prong approach is adopted. On the one hand, scenarios with tolerable transient heat and particle loads, including active edge localised mode (ELM) control are developed. On the other hand, divertor solutions including advanced magnetic configurations are studied. Considerable progress has been made on both approaches, in particular in the fields of: ELM control with resonant magnetic perturbations (RMP), small ELM regimes, detachment onset and control, as well as filamentary scrape-off-layer transport. For example full ELM suppression has now been achieved on AUG at low collisionality with n  =  2 RMP maintaining good confinement HH(98,y2)≈0.95. Advances have been made with respect to detachment onset and control. Studies in advanced divertor configurations (Snowflake, Super-X and X-point target divertor) shed new light on SOL physics. Cross field filamentary transport has been characterised in a wide parameter regime on AUG, MAST and TCV progressing the theoretical and experimental understanding crucial for predicting first wall loads in ITER and DEMO. Conditions in the SOL also play a crucial role for ELM stability and access to small ELM regimes.Integrating the plasma core performance with an edge and scrape-off layer (SOL) that leads to tolerable heat and particle loads on the wall is a major challenge. The new European medium size tokamak task force (EU-MST) coordinates research on ASDEX Upgrade (AUG), MAST and TCV. This multi-machine approach within EU-MST, covering a wide parameter range, is instrumental to progress in the field, as ITER and DEMO core/pedestal and SOL parameters are not achievable simultaneously in present day devices. A two prong approach is adopted. On the one hand, scenarios with tolerable transient heat and particle loads, including active edge localised mode (ELM) control are developed. On the other hand, divertor solutions including advanced magnetic configurations are studied. Considerable progress has been made on both approaches, in particular in the fields of: ELM control with resonant magnetic perturbations (RMP), small ELM regimes, detachment onset and control, as well as filamentary scrape-off-layer transport. For example full ELM suppression has now been achieved on AUG at low collisionality with n = 2 RMP maintaining good confinement H-H(98,H-y2) approximate to 0.95. Advances have been made with respect to detachment onset and control. Studies in advanced divertor configurations (Snowflake, Super-X and X-point target divertor) shed new light on SOL physics. Cross field filamentary transport has been characterised in a wide parameter regime on AUG, MAST and TCV progressing the theoretical and experimental understanding crucial for predicting first wall loads in ITER and DEMO. Conditions in the SOL also play a crucial role for ELM stability and access to small ELM regimes.Peer reviewe

Reliability evaluation of metal oxide varistors for maintenance scheduling

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Modelling of the effect of ELMs on fuel retention at the bulk W divertor of JET

Effect of ELMs on fuel retention at the bulk W target of JET ITER-Like Wall was studied with multi-scale calculations. Plasma input parameters were taken from ELMy H-mode plasma experiment. The energetic intra-ELM fuel particles get implanted and create near-surface defects up to depths of few tens of nm, which act as the main fuel trapping sites during ELMs. Clustering of implantation-induced vacancies were found to take place. The incoming flux of inter-ELM plasma particles increases the different filling levels of trapped fuel in defects. The temperature increase of the W target during the pulse increases the fuel detrapping rate. The inter-ELM fuel particle flux refills the partially emptied trapping sites and fills new sites. This leads to a competing effect on the retention and release rates of the implanted particles. At high temperatures the main retention appeared in larger vacancy clusters due to increased clustering rate

Epidemiological characteristics and management of Gram-negative bacteraemia in different immunocompromised hosts: Observational single-center study

Importance Patients with Gram-negative bloodstream infections (GN-BSI) are classified as non-immunocompromised (n-IC) or immunocompromised (IC). However, immunosuppressive condition should not be considered univocally.Objective To investigate epidemiological characteristics, management and outcome of GN-BSI in IC and non-IC patients. Methods Retrospective single-center study of hospitalized patients with GN-BSI conducted over a 7-year period. Patients with GN-BSI were divided in: solid organ transplant (SOT) recipients, patients with hematologic malignancy (HM), patients with metastatic solid cancer (mSC), and non-major IC patients (nm-IC). Results 3544 patients analysed: 76.7% nm-IC, 6.5% SOT, 8.0% HM and 8.8% mSC. SOT and HM patients were younger (SOT: 56.6 +/- 13.1 years; HM: 56.4 +/- 14.5; nm-IC: 72.4 +/- 16.1; mSC: 68.6 +/- 13.1, p < 0.001) and had lower CCI value (SOT: 4.5 +/- 2.4; HM: 4.1 +/- 2.1; nm-IC: 5.5 +/- 2.6; mSC: 9.7 +/- 2.5, p < 0.001). Urinary tract infection was the most common source of BSI in nm-IC (nm-IC: 50.1%, HM:15%; SOT: 33.3%; mSC: 25.9%, p < 0.001), intra-abdominal infection was the more frequent source among SOT and mSC (SOT:42.3%; mSC: 49.3%, nm-IC: 27.8%, HM:29%; p < 0.001). Primary BSI was the first cause of GN-BSI in HM (HM: 62.1%; SOT: 18.5%; nm-IC: 17.2%; mSC: 10.6%, p < 0.001). The lowest rate of death was observed in SOT and the highest in mSC (SOT 8.2%; nm-IC 13.4%; HM 14.9%; mSC 19.9%, p < 0.001). Relapse rate was highest in SOT (SOT: 18.8%; HM: 11.8%; NMIC: 7.2%; aST: 7.1%, p < 0.001). Follow-up bloodcultures were associated with a lower mortality only among NMIC (HR = 0.317, 95% CI 0.178-0.563, p < 0.001) and aST (HR = 0.198, 95% CI 0.058-0.673, p = 0.010). The role of treatment duration on relapse was not evident in any group, conversely receiving at least 7 days of treatment was associated with a lower risk of 90-day mortality in SOT and HM patients. Conclusions The characteristics and outcome of GN-BSI are peculiar between specific IC categories, therefore a personalized management should be implemented

Long-term immune response after SARS-CoV2 vaccination in solid organ transplant recipients

BackgroundSevere Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) vaccination in solid organ transplant (SOT) recipients is associated with suboptimal antibody response (AbR) favouring breakthrough infection (BI). The role of cell-mediated immunity (CMI) remains uncertain.MethodsSingle-center prospective longitudinal cohort study of adult SOT recipients monitored for both AbR and CMI at 6 +/- 2 months after booster dosage of SARS-CoV-2 vaccine. Primary end-point was BI diagnosis and CMI was the main risk factor. Relationship between CMI and BI was investigated by bivariate tests and multivariable logistic regression.ResultsCMI was performed in 139 patients. In 66 patients BI was documented before CMI, thus 73 (33 kidney, 24 liver, 14 lung, 2 heart) were analysed. The first 2 vaccine doses consisted of BNT162b2 and mRNA-1273 in 69.1% and 30.9% of cases, respectively. Whereas mRNA-1273 was used as for third dose in 91.2% of patients. At a median of 215 (IQR 181-252) days after booster dose, 40 (54.8%) patients displayed both AbR and CMI, 21 (28.8%) only AbR and 12 (16.4%) neither AbR or CMI; there were no patients showing negative AbR and positive CMI. Overall, 22 (30.1%) patients reported BI with no significant differences between those with positive vs. negative CMI (59.1% vs. 40.9%, p = 0.798), confirmed by multiple logistic regression after adjusting for age, type of vaccine and organs, high AbR and time from transplant.ConclusionOur data suggest that in the solid organ transplant population of our cohort, cell-mediated immunity does not appear to be a strong predictor of BI