Efficient and accurate calculation of dispersion relations for intrinsically unstable premixed flames

Premixed flames are susceptible to hydrodynamic and thermodiffusive instabilities that wrinkle the flame front and lead to complex multiscale patterns. They strongly impact the flame propagation and dynamics, increasing the speed of a laminar flame by several folds, easily as large as a factor of five for lean hydrogen flames at high pressure. The dispersion relation, which represents the growth rate of the different harmonic components of the perturbation of the flame front for different wavelengths, is useful to understand the dynamics during the linear phase of flame instabilities. In this work, an efficient and accurate approach based on a Fourier analysis of flame wrinkling is proposed to calculate the dispersion relation. Differently from the typical approach based on perturbing the flame with a single wavelength, the flame is perturbed with a spectrum of sine waves and their growth is followed with a spectral analysis. With the present method, the full dispersion relation is computed with a single simulation; this is significantly more efficient computationally than running a series of simulations with a single-wavelength perturbation for each point of the dispersion relation. It is shown that the presented approach is accurate and also solves an issue encountered when a single perturbation is imposed to compute the growth rate of large wavelengths. Several numerical and initialisation parameters, including resolution, domain size, and amplitude of the initial perturbation, are studied systematically and assessed

Exploiting SMART pass filter deactivation detection to minimize inappropriate subcutaneous implantable cardioverter defibrillator therapies: a real-world single-centre experience and management guide

AIMS: The SMART Pass™ (SP) algorithm is a high-pass filter that aims to reduce inappropriate therapy (IT) in subcutaneous internal cardiac defibrillator (S-ICD), but SP can deactivate due to low amplitude sensed R waves or asystole. The association between IT and SP deactivation and management strategies were evaluated, hypothesizing SP deactivation increases the risk of IT and device re-programming, or lead/generator re-positioning could reduce this risk. METHODS AND RESULTS: Retrospective single-centre audit of Emblem™ S-ICD devices implanted 2016 to 2020 utilizing health records and remote monitoring data. Cox regression models evaluated associations between SP deactivation and IT. A total of 348 patients (27 ± 16.6 months follow-up) were studied: 73% primary prevention. Thirty-eight patients (11.8%) received 83 shocks with 27 patients (7.8%) receiving a total of 44 IT. Causes of IT were oversensing (98%) and aberrantly conducted atrial fibrillation (2%). SP deactivation occurred in 32 of 348 patients (9%) and was significantly associated with increased risk of IT (hazard ratio 5.36, 95% CI 2.37-12.13). SP deactivation was due to low amplitude R waves (94%), associated with a higher defibrillation threshold at implant and presence of arrhythmogenic right ventricular cardiomyopathy. No further IT occurred 16 ± 15.5 months after corrective interventions, with changing the sensing vector being successful in 59% of cases. CONCLUSION: To reduce the risk of IT, the cause of the SP deactivation should be investigated, and appropriate reprogramming, device, or lead modifications made. Utilizing the alert for SP deactivation and electrograms could pro-actively prevent IT

Is there a place for nutritional supplements in the treatment of idiopathic male infertility?

Objective: Infertility affects 15% of couples in fertile age. Male factor is a cause of infertility in almost half of cases, mainly due to oligoasthenoteratozoospermia (OAT). The purpose of this study is to review the effects of nutritional supplements as medical treatment for idiopathic male infertility. Material and methods: A Pub Med and Medline review of the published studies utilizing nutritional supplements for the treatment of male infertility has been performed. Results: Clinical trials on Vitamin E, Vitamin A, Vitamin C. Arginine, Carnitine, N-Acetyl-Carnitine, Glutathione, Coenzyme Q10, Selenium and Zinc were reviewed. Although there is a wide variability in selected population, dose regimen and final outcomes, nutritional supplements both alone and in combination seems to be able to improve semen parameters (sperm count, sperm motility and morphology) and pregnancy rate in infertile men. Conclusions: There are rising evidences from published randomized trials and systematic review suggesting that nutritional supplementation may improve semen parameters and the likelihood of pregnancy in men affected by OAT. This improvement, however, is not consistent and there is a wide variation in the treatment regimens used. Well designed and adequately powered RCTs are needed to better clarify the role of nutritional supplements as treatment for male infertility

I.S.Mu.L.T - Rotator cuff tears guidelines

Despite the high level achieved in the field of shoulder surgery, a global consensus on rotator cuff tears management is lacking. This work is divided into two main sessions: in the first, we set questions about hot topics involved in the rotator cuff tears, from the etiopathogenesis to the surgical treatment. In the second, we answered these questions by mentioning Evidence Based Medicine. The aim of the present work is to provide easily accessible guidelines: they could be considered as recommendations for a good clinical practice developed through a process of systematic review of the literature and expert opinion, in order to improve the quality of care and rationalize the use of resources

Validation of the Italian version of wisconsin stone quality of life (WISQOL): a prospective Italian multicenter study

Urolithiasis is a worldwide spread condition that affects patients' Health-Related Quality of Life (HRQOL), which measurement is an important tool for routine clinical and research practice. Disease-specific HRQOL measures demonstrated to perform better in assessing the effects of specific conditions. A disease-specific questionnaire for kidney stones, the WISQOL, has been validated in different languages, but an Italian version is still missing. Our aim is to produce and validate the Italian version of WISQOL (IT-WISQOL). Patients undergoing any elective treatment for upper urinary tract stones were enrolled. A multi-step process with forward- and back-translation was used to translate WISQOL into Italian. Patients were evaluated within 15 days pre-operatively and then at 30-, 90 days post-operatively and administered both IT-WISQOL and SF-36v2. Post-operative data such as 30 days postoperative complications, late stone-related events, successful status, and stone complexity were collected. Cronbach's α was used to evaluate the internal consistency of IT-WISQOL, while Spearman's rho was used for item and inter-domain correlations and IT-WISQOL with SF-36v2 correlation. We found excellent internal consistency across all domains (α ≥ 0.88), particularly when the total score is considered (α = 0.960). Test-retest reliability showed excellent results for the total questionnaire (Pearson correlation value: 0.85). The Inter-domain association ranged from 0.497 to 0.786. Convergent validity was confirmed by a good correlation with subdomains of the SF-36v2 measures. IT-WISQOL is a reliable tool to measure HRQOL in stone patients. It shows analog characteristics if compared to English WISQOL

Ethnicity and COVID-19 cardiovascular complications: a multi-center UK cohort

BACKGROUND: Recent reports suggest an association between ethnicity and COVID-19 mortality. In the present multi-center study, we aimed to assess the differences underlying this association, and ascertain whether ethnicity also mediates other aspects of COVID-19 like cardiovascular complications. METHODS: Data were collected from a mixed-ethnicity UK cohort of 613 patients admitted and diagnosed COVID-19 positive, across six hospitals in London during the second half of March 2020: 292 were White Caucasian ethnicity, 203 were Asian and 118 were of Afro-Caribbean ethnicity. RESULTS: Caucasian patients were older (P<0.001) and less likely to have hypertension (P=0.038), while Afro-Caribbean patients had higher prevalence of diabetes mellitus (P<0.001). Asian patients were more likely to present with venous thromboembolic disease (adj.OR=4.10, 95% CI 1.49-11.27, P=0.006). On the other hand, Afro-Caribbean had more heart failure (adj.OR=3.64, 95% CI 1.50-8.84, P=0.004) and myocardial injury (adj.OR=2.64, 95% CI 1.10-6.35, P=0.030). Importantly, our adjusted multi-variate Cox regression analysis revealed significantly higher all-cause mortality both for Asian (adj.HR=1.89, 95% CI 1.23-2.91, P=0.004) and Afro-Caribbean ethnicity (adj.HR=2.09, 95% CI 1.30-3.37, P=0.002). CONCLUSIONS: Our data show that COVID-19 may have different presentations and follow different clinical trajectories depending on the ethnicity of the affected subject. Awareness of complications more likely to arise in specific ethnicities will allow a more timely diagnosis and preventive measures for patients at risk. Due to increased mortality, individuals of Afro-Caribbean and Asian ethnicity should be considered as high-risk groups. This may have an impact on health-resource allocation and planning, definition of vulnerable groups, disease management, and the protection of healthcare workers at the frontline

High sensitivity troponin and COVID-19 outcomes

Background: Recent reports have demonstrated high troponin levels in patients affected with COVID-19. In the present study, we aimed to determine the association between admission and peak troponin levels and COVID-19 outcomes. / Methods: This was an observational multi-ethnic multi-centre study in a UK cohort of 434 patients admitted and diagnosed COVID-19 positive, across six hospitals in London, UK during the second half of March 2020. / Results: Myocardial injury, defined as positive troponin during admission was observed in 288 (66.4%) patients. Age (OR: 1.68 [1.49–1.88], p <.001), hypertension (OR: 1.81 [1.10–2.99], p =.020) and moderate chronic kidney disease (OR: 9.12 [95% CI: 4.24–19.64], p <.001) independently predicted myocardial injury. After adjustment, patients with positive peak troponin were more likely to need non-invasive and mechanical ventilation (OR: 2.40 [95% CI: 1.27–4.56], p =.007, and OR: 6.81 [95% CI: 3.40–13.62], p <.001, respectively) and urgent renal replacement therapy (OR: 4.14 [95% CI: 1.34–12.78], p =.013). With regards to events, and after adjustment, positive peak troponin levels were independently associated with acute kidney injury (OR: 6.76 [95% CI: 3.40–13.47], p <.001), venous thromboembolism (OR: 11.99 [95% CI: 3.20–44.88], p <.001), development of atrial fibrillation (OR: 10.66 [95% CI: 1.33–85.32], p =.026) and death during admission (OR: 2.40 [95% CI: 1.34–4.29], p =.003). Similar associations were observed for admission troponin. In addition, median length of stay in days was shorter for patients with negative troponin levels: 8 (5–13) negative, 14 (7–23) low-positive levels and 16 (10–23) high-positive (p <.001). / Conclusions: Admission and peak troponin appear to be predictors for cardiovascular and non-cardiovascular events and outcomes in COVID-19 patients, and their utilisation may have an impact on patient management

Amplified sinus-P-wave analysis predicts outcomes of cryoballoon ablation in patients with persistent and long-standing persistent atrial fibrillation: A multicentre study

IntroductionOutcomes of catheter ablation for non-paroxysmal atrial fibrillation (AF) remain suboptimal. Non-invasive stratification of patients based on the presence of atrial cardiomyopathy (ACM) could allow to identify the best responders to pulmonary vein isolation (PVI).MethodsObservational multicentre retrospective study in patients undergoing cryoballoon-PVI for non-paroxysmal AF. The duration of amplified P-wave (APW) was measured from a digitally recorded 12-lead electrocardiogram during the procedure. If patients were in AF, direct-current cardioversion was performed to allow APW measurement in sinus rhythm. An APW cut-off of 150 ms was used to identify patients with significant ACM. We assessed freedom from arrhythmia recurrence at long-term follow-up in patients with APW ≥ 150 ms vs. APW &lt; 150 ms.ResultsWe included 295 patients (mean age 62.3 ± 10.6), of whom 193 (65.4%) suffered from persistent AF and the remaining 102 (34.6%) from long-standing persistent AF. One-hundred-forty-two patients (50.2%) experienced arrhythmia recurrence during a mean follow-up of 793 ± 604 days. Patients with APW ≥ 150 ms had a significantly higher recurrence rate post ablation compared to those with APW &lt; 150 ms (57.0% vs. 41.6%; log-rank p &lt; 0.001). On a multivariable Cox-regression analysis, APW≥150 ms was the only independent predictor of arrhythmia recurrence post ablation (HR 2.03 CI95% 1.28–3.21; p = 0.002).ConclusionAPW duration predicts arrhythmia recurrence post cryoballoon-PVI in persistent and long-standing persistent AF. An APW cut-off of 150 ms allows to identify patients with significant ACM who have worse outcomes post PVI. Analysis of APW represents an easy, non-invasive and highly reproducible diagnostic tool which allows to identify patients who are the most likely to benefit from PVI-only approach

Prevalence of Rheumatic Heart Disease in North Madagascar: An echocardiographic screening in young and adult populations

BackgroundRheumatic Heart Disease (RHD) prevalence in Madagascar is poorly known. Echocardiographic screening detects a higher prevalence of RHD than clinical examination.AimsWe aimed to describe RHD prevalence in children and adults in North Madagascar using the most updated World Heart Federation (WHF) criteria for RHD echocardiographic diagnosis.Methods Children aged 5–19 years (Group One) and adults aged more than 20 years (Group Two) underwent a four-steps visit: clinical questionnaire, physical examination, laboratory test - oropharyngeal swab for Group One and Anti-streptolysin O (ASO) titre for Group Two - and echocardiogram using a portable machine..Results Among 859 people (522 in Group One, 337 in Group Two) RHD prevalence was 2.1 per cent. Group Two had a higher risk of having RHD than Group One (OR 4.39, CI 1.39–13.9, p=0.004), while clinical findings were more frequent in Group One (children had a higher risk of heart murmur (O.R. 3.85 C.I. 1.08–13.72; p=0.029)). RHD prevalence was 1.34 per cent in children. Those positive to oropharyngeal swab had a higher risk of RHD (OR 14.5, CI 3.04–69.44, p=0.0024); children with history of fever and sore-throat had a higher risk of positive oropharyngeal swab (OR 15.97, CI 3.14–81.19, p=0.002). RHD prevalence was 3.3 per cent in adults. None of those had history of fever and throat-pain, positive ASO titre and cardiac murmur simultaneously. ConclusionThis is the first study describing prevalence of RHD in Madagascar. Our results, although preliminary, are important to enhance prevention programs in this country