High-frequency QRS analysis compared to conventional ST-segment analysis in patients with chest pain and normal ECG referred for exercise tolerance test

Background: The novel analysis of high-frequency QRS components (HFQRS-analysis) has been proposed in patients with chest pain (CP) and normal electrocardiography (ECG) referred for exercise tolerance test (ex-ECG). The aim of the study was to compare the diagnostic value of ex-ECG with ex-HFQRS-analysis. Methods: Patients with CP and normal ECG, troponin, and echocardiography were consid­ered. All patients underwent ex-ECG for conventional ST-segment-analysis and ex-HFQRS-analysis. A decrease ≥ 50% of the HFQRS signal intensity recorded in at least 2 contiguous leads was considered an index of ischemia, as ST-segment depression ≥ 2 mm or ≥ 1 mm and CP on ex-ECG. Exclusion criteria were: QRS duration ≥ 120 ms and inability to exercise. End-point: The composite of coronary stenosis ≥ 70% or acute coronary syndrome, revascu­larization, cardiovascular death at 3-month follow-up. Results: Three-hundred thirty-seven patients were enrolled (age 60 ± 15 years). The percent­age of age-adjusted maximal predicted heart rate was 89 ± 10 beat per minute and the maximal systolic blood pressure was 169 ± 23 mm Hg. Nineteen patients achieved the end-point. In multivariate analysis, both ex-ECG and ex-HFQRS were predictors of the end-point. The ex-HFQRS-analysis showed higher sensitivity (63% vs. 26%; p < 0.05), lower specificity (68% vs. 95%; p < 0.001), and comparable negative predictive value (97% vs. 96%; p = 0.502) when compared to ex-ECG-analysis. Receiver operator characteristics analysis showed the incremental diagnostic value of HFQRS (area: 0.655, 95% CI 0.60–0.71) over conventional ex-ECG (0.608, CI 0.55–0.66) and CP score (0.530, CI 0.48–0.59), however without statistical significance in pairwise comparison by C-statistic. Conclusions: In patients with CP submitted to ex-ECG, the novel ex-HFQRS-analysis shows a valuable incremental diagnostic value over ST-segment-analysis

Environmentally Friendly Pathway to Kesterite Nanoparticles with Controlled Sn Content: An In-Depth Study of Magnetic and Optical Properties

Copper-poor Cu2ZnSnS4 (copper zinc tin sulfide, CZTS) inorganic semiconducting nanoparticles were synthesized by an environmentally friendly low-temperature (100 degrees C) synthetic path, which allows precise control of the Sn content without any relevant presence of Zn- and Sn-related secondary phases. The resulting nanoparticles are polycrystalline and quasi-spherical, with an average diameter of 10 nm. The shape and composition were assessed using a multitechnique approach based on X-ray photoelectron spectroscopy (XPS), energy-dispersive fluorescence X-ray spectroscopy (EDXRF), inductively coupled plasma atomic emission spectrometry (ICP-AES), and high-resolution transmission electron microscopy (HR-TEM). The presence of paramagnetic species associated with Cu2+ cations was highlighted by electron paramagnetic resonance (EPR) spectroscopy, pinpointing the presence of significant exchange interactions between Cu2+ ions. The mixed oxidation state of Cu induces the generation of free holes, which are confined in the nanoparticles, giving rise to a plasmonic resonance. The plasmonic properties were investigated as a function of Sn doping through vis-NIR absorption spectroscopy combined with magnetic circular dichroism (MCD). This approach enabled the extraction of charge carriers' density and mass, a key step for further optimization of CZTS-based photovoltaic devices

Selective electrodesorption based atomic layer deposition (SEBALD) modifications of silver surfaces for enhancing oxygen reduction reaction activity

The increasing attention addressed toward the synergic effect of various metals on the catalysis of one of the most important electrocatalytic reaction, such as the Oxygen Reduction Reaction (ORR), led us to study the effect of monolayers of Fe and of mixed Fe and Co on Ag(111), whose catalytic activity is already known and well characterized. Fe and Co/Fe clusters were obtained by the Selective Electrodesorption Based Atomic Layer Deposition (SEBALD) method, which is a novel electrochemical route to deposit metal clusters on a foreign substrate recently proposed by our group. SEBALD of Fe or Co/Fe resulted in an enhanced catalytic activity; Co/Fe in particular was demonstrated to assemble in small clusters, providing access of the electrolyte to Ag and enabling a bimetallic catalytic effect

Electrodeposition in the Energy field

Electrodeposition in the Energy fiel