Long Term Partial Discharge Behavior of Protrusion Defect in HVDC GIS

2022 IEEE. Personal use of this material is permitted. Permissíon from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertisíng or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.[EN] This article investigates the partial discharge (PD) behavior of protrusion defects in real-size high-voltage direct current gas insulated switchgear (HVDC GIS) for SF6 and SF6 alternative gases including fluoronitrile-CO2 mixture (10%) and fluoroketone-dry air mixture (6.6%). The evolution of PD apparent charge and PD repetition rate for all investigated gases is presented and discussed. The measurement results indicate that PD behavior changes as a function of time. The PD apparent charge increases and the PD repetition rate decreases with the increase of voltage application time. This evolution can be related to the change in protrusion tip radius due to electrochemical etching: radius of the protrusion's tip being enlarged. In addition, the pulse sequence analysis (PSA) plots of the PDs caused by this defect are presented. It is observed that the PSA plots change over time. Therefore, for the development of a robust PD monitoring and defect-recognition tool, as well as for the assessment of risks in the operation of HVDC GIS, it is crucial to take these changes into account.This work was supported in part by the Horizon 2020 Progress on Meshed HVDC Offshore Transmission Networks (PROMOTioN) Project under Grant 691714 and in part by the French Government through the frame of "Investissements d'avenir," under Grant ANE-ITE-002-01.Vu, C.; Toigo, C.; Jacquier, F.; Girodet, A.; Riechert, U.; Tuczek, MN.; Rodrigo Mor, A. (2022). Long Term Partial Discharge Behavior of Protrusion Defect in HVDC GIS. IEEE Transactions on Dielectrics and Electrical Insulation. 29(6):2294-2302. https://doi.org/10.1109/TDEI.2022.32067262294230229

Epicardial fat volume is associated with coronary endothelium-dependent vasomotor response in healthy subjects

Poster presentationInternational audienc

Gender differences in response to cold pressor test assessed with velocity-encoded cardiovascular magnetic resonance of the coronary sinus

BACKGROUND: Gender-specific differences in cardiovascular risk are well known, and current evidence supports an existing role of endothelium in these differences. The purpose of this study was to assess non invasively coronary endothelial function in male and female young volunteers by myocardial blood flow (MBF) measurement using coronary sinus (CS) flow quantification by velocity encoded cine cardiovascular magnetic resonance (CMR) at rest and during cold pressor test (CPT). METHODS: Twenty-four healthy volunteers (12 men, 12 women) underwent CMR in a 3 Tesla MR imager. Coronary sinus flow was measured at rest and during CPT using non breath-hold velocity encoded phase contrast cine-CMR. Myocardial function and morphology were acquired using a cine steady-state free precession sequence. RESULTS: At baseline, mean MBF was 0.63 ± 0.23 mL·g⁻¹·min⁻¹ in men and 0.79 ± 0.21 mL·g⁻¹·min⁻¹ in women. During CPT, the rate pressure product in men significantly increased by 49 ± 36% (p \textless 0.0001) and in women by 52 ± 22% (p \textless 0.0001). MBF increased significantly in both men and women by 0.22 ± 0.19 mL·g⁻¹·min⁻¹ (p = 0.0022) and by 0.73 ± 0.43 mL·g⁻¹·min⁻¹ (p = 0.0001), respectively. The increase in MBF was significantly higher in women than in men (p = 0.0012). CONCLUSION: CMR coronary sinus flow quantification for measuring myocardial blood flow revealed a higher response of MBF to CPT in women than in men. This finding may reflect gender differences in endothelial-dependent vasodilatation in these young subjects. This non invasive rest/stress protocol may become helpful to study endothelial function in normal physiology and in physiopathology

Effects of Bariatric Surgery on Cardiac Ectopic Fat Lesser Decrease in Epicardial Fat Compared to Visceral Fat Loss and No Change in Myocardial Triglyceride Content

ObjectivesThis study investigated the effect of bariatric surgery (BS)–induced weight loss on cardiac ectopic fat using 3T magnetic resonance imaging in morbid obesity.BackgroundHeart disease is one of the leading causes of mortality and morbidity in obese patients. Deposition of cardiac ectopic fat has been related to increased heart risk. Whether sustained weight loss can modulate epicardial fat or myocardial fat is unknown.MethodsTwenty-three morbidly obese patients underwent 1H-magnetic resonance spectroscopy to determine myocardial triglyceride content (MTGC), magnetic resonance imaging to assess epicardial fat volume (EFV), cardiac function, and computed tomography visceral abdominal fat (VAF) measurements at baseline and 6 months after BS.ResultsThe BS reduced body mass index significantly, from 43.1 ± 4.5 kg/m2 to 32.3 ± 4.0 kg/m2, subcutaneous fat from 649 ± 162 cm2 to 442 ± 127 cm2, VAF from 190 ± 83 cm2 to 107 ± 44 cm2, and EFV from 137 ± 37 ml to 98 ± 25 ml (all p < 0.0001). There was no significant change in MTGC: 1.03 ± 0.2% versus 1.1 ± 0.2% (p = 0.85). A significant reduction in left ventricular mass (118 ± 24 g vs. 101 ± 18 g) and cardiac output (7.1 ± 1.6 l/min vs. 5.4 ± 1.0 l/min) was observed and was statistically associated with weight loss (p < 0.05). The loss in EFV was limited (−27 ± 11%) compared to VAF diminution (−40 ± 19%). The EFV variation was not correlated with percentage of body mass index or VAF loss (p = 0.007). The ratio of %EFV to %VAF loss decreased with sleep apnea syndrome (1.34 ± 0.3 vs. 0.52 ± 0.08, p < 0.05).ConclusionsSix-month BS modulates differently cardiac ectopic fat deposition, with a significant decrease in epicardial fat and no change in myocardial fat. Epicardial fat volume loss was limited in patients with sleep apnea. (Impact of Bariatric Surgery on Epicardial Adipose Tissue and on Myocardial Function; NCT01284816

Gcn4 misregulation reveals a direct role for the evolutionary conserved EKC/KEOPS in the t6A modification of tRNAs

The EKC/KEOPS complex is universally conserved in Archaea and Eukarya and has been implicated in several cellular processes, including transcription, telomere homeostasis and genomic instability. However, the molecular function of the complex has remained elusive so far. We analyzed the transcriptome of EKC/KEOPS mutants and observed a specific profile that is highly enriched in targets of the Gcn4p transcriptional activator. GCN4 expression was found to be activated at the translational level in mutants via the defective recognition of the inhibitory upstream ORFs (uORFs) present in its leader. We show that EKC/KEOPS mutants are defective for the N6-threonylcarbamoyl adenosine modification at position 37 (t6A37) of tRNAs decoding ANN codons, which affects initiation at the inhibitory uORFs and provokes Gcn4 de-repression. Structural modeling reveals similarities between Kae1 and bacterial enzymes involved in carbamoylation reactions analogous to t6A37 formation, supporting a direct role for the EKC in tRNA modification. These findings are further supported by strong genetic interactions of EKC mutants with a translation initiation factor and with threonine biosynthesis genes. Overall, our data provide a novel twist to understanding the primary function of the EKC/KEOPS and its impact on several essential cellular functions like transcription and telomere homeostasis

Effect of Hydrocortisone on Mortality and Organ Support in Patients With Severe COVID-19: The REMAP-CAP COVID-19 Corticosteroid Domain Randomized Clinical Trial.

Importance: Evidence regarding corticosteroid use for severe coronavirus disease 2019 (COVID-19) is limited. Objective: To determine whether hydrocortisone improves outcome for patients with severe COVID-19. Design, Setting, and Participants: An ongoing adaptive platform trial testing multiple interventions within multiple therapeutic domains, for example, antiviral agents, corticosteroids, or immunoglobulin. Between March 9 and June 17, 2020, 614 adult patients with suspected or confirmed COVID-19 were enrolled and randomized within at least 1 domain following admission to an intensive care unit (ICU) for respiratory or cardiovascular organ support at 121 sites in 8 countries. Of these, 403 were randomized to open-label interventions within the corticosteroid domain. The domain was halted after results from another trial were released. Follow-up ended August 12, 2020. Interventions: The corticosteroid domain randomized participants to a fixed 7-day course of intravenous hydrocortisone (50 mg or 100 mg every 6 hours) (n = 143), a shock-dependent course (50 mg every 6 hours when shock was clinically evident) (n = 152), or no hydrocortisone (n = 108). Main Outcomes and Measures: The primary end point was organ support-free days (days alive and free of ICU-based respiratory or cardiovascular support) within 21 days, where patients who died were assigned -1 day. The primary analysis was a bayesian cumulative logistic model that included all patients enrolled with severe COVID-19, adjusting for age, sex, site, region, time, assignment to interventions within other domains, and domain and intervention eligibility. Superiority was defined as the posterior probability of an odds ratio greater than 1 (threshold for trial conclusion of superiority >99%). Results: After excluding 19 participants who withdrew consent, there were 384 patients (mean age, 60 years; 29% female) randomized to the fixed-dose (n = 137), shock-dependent (n = 146), and no (n = 101) hydrocortisone groups; 379 (99%) completed the study and were included in the analysis. The mean age for the 3 groups ranged between 59.5 and 60.4 years; most patients were male (range, 70.6%-71.5%); mean body mass index ranged between 29.7 and 30.9; and patients receiving mechanical ventilation ranged between 50.0% and 63.5%. For the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively, the median organ support-free days were 0 (IQR, -1 to 15), 0 (IQR, -1 to 13), and 0 (-1 to 11) days (composed of 30%, 26%, and 33% mortality rates and 11.5, 9.5, and 6 median organ support-free days among survivors). The median adjusted odds ratio and bayesian probability of superiority were 1.43 (95% credible interval, 0.91-2.27) and 93% for fixed-dose hydrocortisone, respectively, and were 1.22 (95% credible interval, 0.76-1.94) and 80% for shock-dependent hydrocortisone compared with no hydrocortisone. Serious adverse events were reported in 4 (3%), 5 (3%), and 1 (1%) patients in the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively. Conclusions and Relevance: Among patients with severe COVID-19, treatment with a 7-day fixed-dose course of hydrocortisone or shock-dependent dosing of hydrocortisone, compared with no hydrocortisone, resulted in 93% and 80% probabilities of superiority with regard to the odds of improvement in organ support-free days within 21 days. However, the trial was stopped early and no treatment strategy met prespecified criteria for statistical superiority, precluding definitive conclusions. Trial Registration: ClinicalTrials.gov Identifier: NCT02735707