Engineering bound states in continuum via nonlinearity induced extra dimension

Bound states in continuum (BICs) are localized states of a system possessing significantly large life times with applications across various branches of science. In this work, we propose an expedient protocol to engineer BICs which involves the use of Kerr nonlinearities in the system. The generation of BICs is a direct artifact of the nonlinearity and the associated expansion in the dimensionality of the system. In particular, we consider single and two mode anharmonic systems and provide a number of solutions apposite for the creation of BICs. In close vicinity to the BIC, the steady state response of the system is immensely sensitive to perturbations in natural frequencies of the system and we illustrate its propitious sensing potential in the context of experimentally realizable setups for both optical and magnetic nonlinearities.Comment: 7 pages, 4 figure

Topological transitions in dissipatively coupled Su-Schrieffer-Heeger models

Non-Hermitian topological phenomena have gained much interest among physicists in recent years. In this paper, we expound on the physics of dissipatively coupled Su-Schrieffer-Heeger (SSH) lattices, specifically in systems with bosonic and electrical constituents. In the context of electrical circuits, we demonstrate that a series of resistively coupled LCR circuits mimics the topology of a dissipatively coupled SSH model. In addition, we foreground a scheme to construct dissipatively coupled SSH lattices involving a set of non-interacting bosonic oscillators weakly coupled to engineered reservoirs of modes possessing substantially small lifetimes when compared to other system timescales. Further, by activating the coherent coupling between bosonic oscillators, we elucidate the emergence of non-reciprocal dissipative coupling which can be controlled by the phase of the coherent interaction strength precipitating in phase-dependent topological transitions and skin effect. Our analyses are generic, apropos of a large class of systems involving, for instance, optical and microwave settings, while the circuit implementation represents the most straightforward of them.Comment: 10 pages, 9 figure

Do Omega-3 fatty acids prevent atrial fibrillation after open heart surgery? A meta-analysis of randomized controlled trials

OBJECTIVES: N-3 polyunsaturated fatty acids have been proposed as a novel treatment for preventing postoperative atrial fibrillation due to their potential anti-inflammatory and anti-arrhythmic effects. However, randomized studies have yielded conflicting results. The objective of this study is to review randomized trials of N-3 polyunsaturated fatty acid use for postoperative atrial fibrillation. METHODS: Using the CENTRAL, PUBMED, EMBASE, and LILACS databases, a literature search was conducted to identify all of the studies in human subjects that reported the effects of N-3 polyunsaturated fatty acids on the prevention of postoperative atrial fibrillation in cardiac surgery patients. The final search was performed on January 30, 2011. There was no language restriction, and the search strategy only involved terms for N-3 polyunsaturated fatty acids (or fish oil), atrial fibrillation, and cardiac surgery. To be included, the studies had to be randomized (open or blinded), and the enrolled patients had to be >18 years of age. RESULTS: Four randomized studies (three double-blind, one open-label) that enrolled 538 patients were identified. The patients were predominantly male, the mean age was 62.3 years, and most of the patients exhibited a normal left atrial size and ejection fraction. N-3 polyunsaturated fatty acid use was not associated with a reduction in postoperative atrial fibrillation. Similar results were observed when the open-label study was excluded. CONCLUSIONS: There is insufficient evidence to suggest that treatment with N-3 polyunsaturated fatty acids reduces postoperative atrial fibrillation. Therefore, their routine use in patients undergoing cardiac surgery is not recommended

SARS-COV-ATE risk assessment model for arterial thromboembolism in COVID-19

Patients with SARS-CoV-2 infection are at an increased risk of cardiovascular and thrombotic complications conferring an extremely poor prognosis. COVID-19 infection is known to be an independent risk factor for acute ischemic stroke and myocardial infarction (MI). We developed a risk assessment model (RAM) to stratify hospitalized COVID-19 patients for arterial thromboembolism (ATE). This multicenter, retrospective study included adult COVID-19 patients admitted between 3/1/2020 and 9/5/2021. Among 3531 patients from the training cohort, 15.5% developed acute in-hospital ATE, including stroke, MI, and other ATE, compared to 13.4% in the validation cohort. The 16-item final score was named SARS-COV-ATE (Sex: male = 1, Age [40-59 = 2, \u3e 60 = 4], Race: non-African American = 1, Smoking = 1 and Systolic blood pressure elevation = 1, Creatinine elevation = 1; Over the range: leukocytes/lactate dehydrogenase/interleukin-6, B-type natriuretic peptide = 1, Vascular disease (cardiovascular/cerebrovascular = 1), Aspartate aminotransferase = 1, Troponin-I [\u3e 0.04 ng/mL = 1, troponin-I \u3e 0.09 ng/mL = 3], Electrolytes derangement [magnesium/potassium = 1]). RAM had a good discrimination (training AUC 0.777, 0.756-0.797; validation AUC 0.766, 0.741-0.790). The validation cohort was stratified as low-risk (score 0-8), intermediate-risk (score 9-13), and high-risk groups (score ≥ 14), with the incidence of ATE 2.4%, 12.8%, and 33.8%, respectively. Our novel prediction model based on 16 standardized, commonly available parameters showed good performance in identifying COVID-19 patients at risk for ATE on admission

RISK FACTORS OF ARTERIAL THROMBOEMBOLISM IN HOSPITALIZED COVID-19 PATIENTS: A MULTICENTER COHORT STUDY

Background: Endothelial cell dysfunction from infection by SARS-CoV-2 and inflammatory cytokines leading to hyperinflammatory and hypercoagulable state is thought to be the mechanism of arterial thromboembolism (ATE) in COVID-19 patients. COVID-19 infection is known to be an independent risk factor for acute stroke and myocardial infarction (MI). However, data on the risk factors of ATE in hospitalized COVID-19 patients is limited. Methods: This retrospective, multicenter cohort study included adult patients admitted to one quaternary care and three community hospitals with PCR-proven SARS-CoV-2 infection between 3/1/2020 and 12/31/2020. The composite outcome was in-hospital ATE events, including acute ischemic stroke, MI, and other ATE identified by ICD-10 codes. Student t-test was conducted for continuous variables and the Chi-square test for categorical variables. Multivariate logistic regression using forward selection was conducted. All statistical tests were 2-sided with an α level of 0.05. All data was analyzed using R version 4.0.4. Results: The cohort included 3531 patients with 371 (10.5%) patients who developed acute ATE. There were 398 ATE events: 270 patients had MI, 43 had stroke, 85 had other ATE, 12 had MI + stroke, 13 had MI + other ATE, and 2 had stroke + other ATE. The model suggested that initial systolic blood pressure (BP) \u3c90 mmHg and \u3e160 mmHg; elevated initial biomarkers including B-type natriuretic peptide (\u3e100 pg/mL), troponin-I (\u3e0.03 ng/mL), lactate dehydrogenase (\u3e192 U/L), creatine phosphokinase (male \u3e280 U/L and female \u3e155 U/L), C-reactive protein (\u3e0.5 mg/dL), leukocytes (\u3e11 K/uL), lactate (\u3e2.2 mmol/L), and aspartate aminotransferase (\u3e41 U/L); presenting hypoalbuminemia (\u3c3.5 g/dL) and hypomagnesemia (\u3c1.8 mg/dL); age \u3e60; male sex; and history of cerebrovascular accident (CVA), coronary artery disease (CAD), hyperthyroidism, and cigarette smoking were associated with an increased risk of ATE (all p\u3c0.05). Conclusion: Hypo or hypertension on admission, elevated inflammatory and cardiac markers, hypoalbuminemia, hypomagnesemia, smoking, and comorbidities including CAD and CVA are associated with ATE in hospitalized COVID-19 patients

Venous thromboembolism in COVID-19 patients and prediction model: a multicenter cohort study

BACKGROUND: Patients with COVID-19 infection are commonly reported to have an increased risk of venous thrombosis. The choice of anti-thrombotic agents and doses are currently being studied in randomized controlled trials and retrospective studies. There exists a need for individualized risk stratification of venous thromboembolism (VTE) to assist clinicians in decision-making on anticoagulation. We sought to identify the risk factors of VTE in COVID-19 patients, which could help physicians in the prevention, early identification, and management of VTE in hospitalized COVID-19 patients and improve clinical outcomes in these patients. METHOD: This is a multicenter, retrospective database of four main health systems in Southeast Michigan, United States. We compiled comprehensive data for adult COVID-19 patients who were admitted between 1st March 2020 and 31st December 2020. Four models, including the random forest, multiple logistic regression, multilinear regression, and decision trees, were built on the primary outcome of in-hospital acute deep vein thrombosis (DVT) and pulmonary embolism (PE) and tested for performance. The study also reported hospital length of stay (LOS) and intensive care unit (ICU) LOS in the VTE and the non-VTE patients. Four models were assessed using the area under the receiver operating characteristic curve and confusion matrix. RESULTS: The cohort included 3531 admissions, 3526 had discharge diagnoses, and 6.68% of patients developed acute VTE (N = 236). VTE group had a longer hospital and ICU LOS than the non-VTE group (hospital LOS 12.2 days vs. 8.8 days, p \u3c 0.001; ICU LOS 3.8 days vs. 1.9 days, p \u3c 0.001). 9.8% of patients in the VTE group required more advanced oxygen support, compared to 2.7% of patients in the non-VTE group (p \u3c 0.001). Among all four models, the random forest model had the best performance. The model suggested that blood pressure, electrolytes, renal function, hepatic enzymes, and inflammatory markers were predictors for in-hospital VTE in COVID-19 patients. CONCLUSIONS: Patients with COVID-19 have a high risk for VTE, and patients who developed VTE had a prolonged hospital and ICU stay. This random forest prediction model for VTE in COVID-19 patients identifies predictors which could aid physicians in making a clinical judgment on empirical dosages of anticoagulation