Individually tailored revascularization improves the outcome of CLI in octogenarians as well as in nonoctogenarians; even so, endovascular revascularization should be preferred in octogenarians because of the higher mortality associated with surgery.

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) could cause virulent infection leading to Corona Virus Disease 2019 (COVID-19)-related pneumonia as well as multiple organ injuries. Hypothesis: COVID-19 infection may result in cardiovascular manifestations leading to worse clinical outcome. Methods: Fifty four severe and critical patients with confirmed COVID-19 were enrolled. Risk factors predicting the severity of COVID-19 were analyzed.Results: Of the 54 patients (56.1 ± 13.5 years old, 66.7% male) with COVID-19, 39 were diagnosed as severe and 15 as critical cases. The occurrence of diabetes, the level of D-dimer, inflammatory and cardiac markers in critical cases were significantly higher. Troponin I (TnI) elevation occurred in 42.6% of all the severe and critical patients. Three patients experienced hypotension at admission and were all diagnosed as critical cases consequently. Hypotension was found in one severe case and seven critical cases during hospitalization. Sinus tachycardia is the most common type of arrythmia and was observed in 23 severe patients and all the critical patients.Atrioventricular block and ventricular tachycardia were observed in critical patients at end stage while bradycardia and atrial fibrillation were less common. Mild pericardial effusion was observed in one severe case and five critical cases. Three critical cases suffered new onset of heart failure. Hypotension during treatment, severe myocardial injury and pericardial effusion were independent risk factors predicting the critical status of COVID-19 infection.

This paper presents developments in numerical simulations of a cross-flow vertical-axis marine current turbine (straight-bladed Darrieus type) with particular emphasis on rotor-performance prediction and hydrodynamic loads for structural design calculations. This study initially used theoretical double-multiple-streamtube models, followed by physical testing on a scaled-down model turbine and primarily numerical simulations. Numerical investigations of a proposed full-scale turbine (power coefficient, blade loads and flow behaviour) were undertaken using the developed computational models. The turbine design was studied using a time-accurate Reynolds-averaged Navier–Stokes (RANS) commercial solver. A transient-rotor-stator model with a moving mesh technique was used to capture the change in flow field at a particular time step. A shear stress-transport [Formula: see text] turbulence model was used to model turbulent features of the flow. The numerical results show good agreement with experimental measurements and the theoretical double-multiple-streamtube model. Turbine sensitivity to parametric variations was also demonstrated in the full-scale numerical study. This work concludes that the developed model can effectively predict hydrodynamic performance and structural design blade loads of a vertical-axis marine current turbine.

In this paper, a locally stationary process is proposed using a Smooth Localized Complex Exponential (SLEX) basis, whose spectrum is assumed to be smooth in both time and frequency. A smoothing Spline ANOVA (SS-ANOVA) is used to estimate and make inference on the time-varying log-spectrum. This approach allows the time and frequency domains to be modeled in an unified approach and jointly estimated. Because the SLEX basis is orthogonal and localized in both time and frequency, our method has good finite sample performance. It also allows for deriving desirable asymptotic properties. Inference procedures such as confidence intervals and hypothesis tests proposed for the SS-ANOVA can be adopted for the time-varying spectrum. Because of the smoothness assumption of the underlying spectrum, once we have the estimates on a time-frequency grid, we can calculate the estimate at any given time and frequency. This leads to a high computational efficiency as for large data sets we only need to estimate the initial raw periodograms at a much coarser grid. We present simulation results and apply our method to an EEG data recorded during an epileptic seizure.

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This work reviews hydrodynamic analysis models developed for the design of Darrieus-type vertical axis marine current turbines, with particular emphasis on the prediction of hydrodynamic rotor performance, as well as their suitability for aiding the optimization process, either directly, or as a fast filter of potential blade profiles.In order to improve the performance of a marine current turbine it is necessary accurately to model the flow passing the turbine's blades. Several types of models exist for Darrieus-type turbines, from momentum-based streamtube models to complex computational fluids dynamics (CFD) simulations. With continuously varying large angles of attack on the blades, the main issue is accurate prediction of the flow field around the rotor and thus its loads and torque. This is further complicated by the significant inherent unsteady hydrodynamic characteristics and potential for dynamic stall. Comparisons of the analytical results with experimental data are presented to compare these different models and thus illustrate their areas of suitability in this context. In conclusion, vertical axis machines have the potential of high power capture compared with that of their horizontal counterparts but this will depend on blade profile and design configuration, solidity, and tip speed ratio. None of the existing theoretical methods really captures the actual performance of the machines except for detailed CFD simulations, which are inevitably computational time intensive.

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