14 research outputs found

    Plasma synthetic jet actuators for biological indirect treatment: the role of the charged particles

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    Plasma Synthetic Jet Actuators (PSJA) have demonstrated their ability to produce a flow from the surface where the Dielectric Barrier Discharge (DBD) is ignited. This ionic wind is due to the Electro Hydro Dynamic (EHD) interaction. These fluid-dynamic actuators enhance the delivery of reactive species towards the target to be treated. The long-life charged particles are generated within the plasma region and then carried on by the induced flow. The disinfection efficacy of PSJA used to indirectly treat different pathogens was demonstrated. In particular, the inactivation effect of free charges advected by the ionic wind has been investigated. An assessment of the various factors that may affect the production and the effect of the free charges are analysed. It was observed that humidity rate weakly influences the charge deposition. Besides, the most notable effect is an increase of the deposition time for higher humidity rate. In addition, a higher applied electric field produces higher charge deposition rates. Moreover, different geometries and dielectric materials have been considered. Linear actuators have proven to be more effective in charge delivery with respect to annular actuators. The EHD interaction was measured also for a streamer corona discharge utilised for cancer cells treatment

    Calcolo delle perdite AC in cavi superconduttori di tipo Cable in Conduit

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    ITER, International Thermonuclear Experimental Reactor, è un progetto internazionale che ha lo scopo di realizzare un reattore sperimentale, per dimostrare la fattibilità tecnica e scientifica della generazione di energia tramite fusione termonucleare controllata. La reazione di fusione è prevista in un tokamak, progettato per produrre 500 MW di potenza termica. Il plasma caldo, necessario alla reazione, deve essere confinato tramite l'uso di intensi campi magnetici. Questi campi, le cui linee di forza sono in direzione polidale e toroidale, sono generati da magneti superconduttori. Il cuore tecnologico dei magneti è costituito dai cavi superconduttori, in cui scorre la corrente necessaria a creare il campo magnetico. In questa tesi sono stati analizzati due cavi, uno per i magneti del campo toroidale e l’altro per il magnete del solenoide centrale, con lo scopo di calcolare le perdite in presenza di un campo magnetico variabile nel tempo e confrontare i dati sperimentali con i valori analitici. L’ambiente in cui sono stati testati, rappresentato dalla facility SULTAN, è stato riprodotto nel codice THELMA. Inoltre, è stata avviata e condotta una collaborazione, tuttora in corso, con un gruppo di ricerca del CEA, Commissione per l’Energia Atomica e le Energie Alternative, con sede a Cadarache, in Francia. Questo gruppo ha elaborato un ulteriore modello per il calcolo delle perdite AC, chiamato M-PAS, Multizone Partial Shielding. Lo scopo della collaborazione è quello di verificare che si ottengano dei risultati coincidenti nei due diversi modelli, analizzando un cavo rettilineo, del tipo CICC, sottoposto all'azione di un campo esterno uniforme nello spazio ma variabile nel tempo, con diverse condizioni al contorno. L’obbiettivo che questa tesi si propone, ovvero il calcolo dell’energia dissipata durante il normale funzionamento dei cavi superconduttori, risulta fondamentale per dimensionare il sistema di raffreddamento dei cavi

    Development of a new generic analytical modeling of AC coupling losses in cable-in-conduit conductors

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    Coupling losses induced in CICCs when subject to a time-varying magnetic field are a major issue commonly encountered in large fusion tokamaks (e.g. JT-60SA, ITER, DEMO). The knowledge of these losses is crucial to determine the stability of CICCs but is yet difficult to achieve analytically (thus in a short computation time) given the specific and complex architecture of these conductors although numerical solutions such as THELMA and JACKPOT already exists. In an attempt to ease the resolution of this problem, we have previously presented a theoretical generic study of a group of elements twisted together (representing a cabling stage of a CICC) and derived the analytical expression of its coupling losses. We have now extended this study to a two cabling stage conductor by establishing an analytical model to calculate its coupling losses as function of its effective features. In a second part, we compare our results to these of THELMA and JACKPOT on geometries representing ITER CS and JT-60SA TF conductors. Finally, we have set up a specific algorithm to reconstruct strand trajectories from X-ray images and have extracted the effective geometrical parameters of a JT-60SA TF conductor

    A multi-country analysis of COVID-19 hospitalizations by vaccination status

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    Background: Individuals vaccinated against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), when infected, can still develop disease that requires hospitalization. It remains unclear whether these patients differ from hospitalized unvaccinated patients with regard to presentation, coexisting comorbidities, and outcomes. Methods: Here, we use data from an international consortium to study this question and assess whether differences between these groups are context specific. Data from 83,163 hospitalized COVID-19 patients (34,843 vaccinated, 48,320 unvaccinated) from 38 countries were analyzed. Findings: While typical symptoms were more often reported in unvaccinated patients, comorbidities, including some associated with worse prognosis in previous studies, were more common in vaccinated patients. Considerable between-country variation in both in-hospital fatality risk and vaccinated-versus-unvaccinated difference in this outcome was observed. Conclusions: These findings will inform allocation of healthcare resources in future surges as well as design of longer-term international studies to characterize changes in clinical profile of hospitalized COVID-19 patients related to vaccination history. Funding: This work was made possible by the UK Foreign, Commonwealth and Development Office and Wellcome (215091/Z/18/Z, 222410/Z/21/Z, 225288/Z/22/Z, and 220757/Z/20/Z); the Bill & Melinda Gates Foundation (OPP1209135); and the philanthropic support of the donors to the University of Oxford's COVID-19 Research Response Fund (0009109). Additional funders are listed in the "acknowledgments" section

    Long-term neurological symptoms after acute COVID-19 illness requiring hospitalization in adult patients: insights from the ISARIC-COVID-19 follow-up study

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    in this study we aimed to characterize the type and prevalence of neurological symptoms related to neurological long-COVID-19 from a large international multicenter cohort of adults after discharge from hospital for acute COVID-19

    Sparsentan in patients with IgA nephropathy: a prespecified interim analysis from a randomised, double-blind, active-controlled clinical trial

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    Background: Sparsentan is a novel, non-immunosuppressive, single-molecule, dual endothelin and angiotensin receptor antagonist being examined in an ongoing phase 3 trial in adults with IgA nephropathy. We report the prespecified interim analysis of the primary proteinuria efficacy endpoint, and safety. Methods: PROTECT is an international, randomised, double-blind, active-controlled study, being conducted in 134 clinical practice sites in 18 countries. The study examines sparsentan versus irbesartan in adults (aged ≥18 years) with biopsy-proven IgA nephropathy and proteinuria of 1·0 g/day or higher despite maximised renin-angiotensin system inhibitor treatment for at least 12 weeks. Participants were randomly assigned in a 1:1 ratio to receive sparsentan 400 mg once daily or irbesartan 300 mg once daily, stratified by estimated glomerular filtration rate at screening (30 to 1·75 g/day). The primary efficacy endpoint was change from baseline to week 36 in urine protein-creatinine ratio based on a 24-h urine sample, assessed using mixed model repeated measures. Treatment-emergent adverse events (TEAEs) were safety endpoints. All endpoints were examined in all participants who received at least one dose of randomised treatment. The study is ongoing and is registered with ClinicalTrials.gov, NCT03762850. Findings: Between Dec 20, 2018, and May 26, 2021, 404 participants were randomly assigned to sparsentan (n=202) or irbesartan (n=202) and received treatment. At week 36, the geometric least squares mean percent change from baseline in urine protein-creatinine ratio was statistically significantly greater in the sparsentan group (-49·8%) than the irbesartan group (-15·1%), resulting in a between-group relative reduction of 41% (least squares mean ratio=0·59; 95% CI 0·51-0·69; p<0·0001). TEAEs with sparsentan were similar to irbesartan. There were no cases of severe oedema, heart failure, hepatotoxicity, or oedema-related discontinuations. Bodyweight changes from baseline were not different between the sparsentan and irbesartan groups. Interpretation: Once-daily treatment with sparsentan produced meaningful reduction in proteinuria compared with irbesartan in adults with IgA nephropathy. Safety of sparsentan was similar to irbesartan. Future analyses after completion of the 2-year double-blind period will show whether these beneficial effects translate into a long-term nephroprotective potential of sparsentan. Funding: Travere Therapeutics

    Implementation of Recommendations on the Use of Corticosteroids in Severe COVID-19

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    Importance: Research diversity and representativeness are paramount in building trust, generating valid biomedical knowledge, and possibly in implementing clinical guidelines. Objectives: To compare variations over time and across World Health Organization (WHO) geographic regions of corticosteroid use for treatment of severe COVID-19; secondary objectives were to evaluate the association between the timing of publication of the RECOVERY (Randomised Evaluation of COVID-19 Therapy) trial (June 2020) and the WHO guidelines for corticosteroids (September 2020) and the temporal trends observed in corticosteroid use by region and to describe the geographic distribution of the recruitment in clinical trials that informed the WHO recommendation. Design, setting, and participants: This prospective cohort study of 434 851 patients was conducted between January 31, 2020, and September 2, 2022, in 63 countries worldwide. The data were collected under the auspices of the International Severe Acute Respiratory and Emerging Infections Consortium (ISARIC)-WHO Clinical Characterisation Protocol for Severe Emerging Infections. Analyses were restricted to patients hospitalized for severe COVID-19 (a subset of the ISARIC data set). Exposure: Corticosteroid use as reported to the ISARIC-WHO Clinical Characterisation Protocol for Severe Emerging Infections. Main outcomes and measures: Number and percentage of patients hospitalized with severe COVID-19 who received corticosteroids by time period and by WHO geographic region. Results: Among 434 851 patients with confirmed severe or critical COVID-19 for whom receipt of corticosteroids could be ascertained (median [IQR] age, 61.0 [48.0-74.0] years; 53.0% male), 174 307 (40.1%) received corticosteroids during the study period. Of the participants in clinical trials that informed the guideline, 91.6% were recruited from the United Kingdom. In all regions, corticosteroid use for severe COVID-19 increased, but this increase corresponded to the timing of the RECOVERY trial (time-interruption coefficient 1.0 [95% CI, 0.9-1.2]) and WHO guideline (time-interruption coefficient 1.9 [95% CI, 1.7-2.0]) publications only in Europe. At the end of the study period, corticosteroid use for treatment of severe COVID-19 was highest in the Americas (5421 of 6095 [88.9%]; 95% CI, 87.7-90.2) and lowest in Africa (31 588 of 185 191 [17.1%]; 95% CI, 16.8-17.3). Conclusions and relevance: The results of this cohort study showed that implementation of the guidelines for use of corticosteroids in the treatment of severe COVID-19 varied geographically. Uptake of corticosteroid treatment was lower in regions with limited clinical trial involvement. Improving research diversity and representativeness may facilitate timely knowledge uptake and guideline implementation
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