Boosting infrared energy transfer in 3D nanoporous gold antennas

The applications of plasmonics to energy transfer from free-space radiation to molecules are currently limited to the visible region of the electromagnetic spectrum due to the intrinsic optical properties of bulk noble metals that support strong electromagnetic field confinement only close to their plasma frequency in the visible/ultraviolet range. In this work, we show that nanoporous gold can be exploited as a plasmonic material for the mid-infrared region to obtain strong electromagnetic field confinement, co-localized with target molecules into the nanopores and resonant with their vibrational frequency. The effective optical response of the nanoporous metal enables the penetration of optical fields deep into the nanopores, where molecules can be loaded thus achieving a more efficient light–matter coupling if compared to bulk gold. In order to realize plasmonic resonators made of nanoporous gold, we develop a nanofabrication method based on polymeric templates for metal deposition and we obtain antenna arrays resonating at mid-infrared wavelengths selected by design. We then coat the antennas with a thin (3 nm) silica layer acting as the target dielectric layer for optical energy transfer. We study the strength of the light–matter coupling at the vibrational absorption frequency of silica at 1240 cm−1 through the analysis of the experimental Fano lineshape that is benchmarked against identical structures made of bulk gold. The boost in the optical energy transfer from free-space mid-infrared radiation to molecular vibrations in nanoporous 3D nanoantenna arrays can open new application routes for plasmon-enhanced physical–chemical reactions

Imaging predictors of incident heart failure: a systematic review and meta-analysis

BACKGROUND: Preventing the evolution of subclinical cardiac disease into overt heart failure is of paramount importance. Imaging techniques, particularly transthoracic echocardiography (TTE), are well suited to identify abnormalities in cardiac structure and function that precede the development of heart failure. METHODS: This meta-analysis provides a comprehensive evaluation of 32 studies from 11 individual cohorts, which assessed cardiac indices from TTE (63%), cardiovascular magnetic resonance (CMR; 34%) or cardiac computed tomography (CCT; 16%). Eligible studies focused on measures of left ventricular geometry and function and were highly heterogeneous. RESULTS: Among the variables that could be assessed through a meta-analytic approach, left ventricular systolic dysfunction, defined as left ventricular ejection fraction (LVEF) lower than 50%, and left ventricular dilation were associated with a five-fold [hazard ratio (HR) 4.76, 95% confidence interval (95% CI) 1.85-12.26] and three-fold (HR 3.14, 95% CI 1.37 -7.19) increased risk of heart failure development, respectively. Any degree of diastolic dysfunction conveyed an independent, albeit weaker, association with heart failure (HR 1.48, 95% CI 1.11-1.96), although there was only a trend for left ventricular hypertrophy in predicting incident heart failure (hazard ratio 2.85, 95% CI 0.82-9.85). CONCLUSION: LVEF less than 50%, left ventricular dilation and diastolic dysfunction are independent predictors of incident heart failure among asymptomatic individuals, while left ventricular hypertrophy seems less predictive. These findings may serve as a framework for implementing imaging-based screening strategies in patients at risk of heart failure and inform future studies testing preventive or therapeutic approaches aiming at thwarting or halting the progression from asymptomatic (preclinical) to overt heart failure

Acute Effects Of Triiodothyronine T. (T3) Replacement Therapy in Patients with Chronic Heart Failure and Low-T3 Syndrome: A Randomized, Placebo-Controlled Study

Context: Low-T3 syndrome is a predictor of poor outcome in patients with cardiac dysfunction. The study aimed to assess the short-term effects of synthetic L-T3 replacement therapy in patients with low-T3 syndrome and ischemic or nonischemic dilated cardiomyopathy (DC). Design:Atotal of 20 clinically stable patients with ischemic (n12) or nonischemic (n8) DC were enrolled. There were 10 patients (average age 72 yr, range 66–77; median, 25–75th percentile) who underwent 3-d synthetic L-T3 infusion (study group); the other 10 patients (average age 68 yr, range 64–71) underwent placebo infusion (control group). Clinical examination, electrocardiography, cardiac magnetic resonance, and bio-humoral profile (free thyroid hormones, TSH, plasma renin activity, aldosterone, noradrenaline, N-terminal-pro-B-Type natriuretic peptide, and IL-6) were assessed at baseline and after 3-d synthetic L-T3 (initial dose: 20 g/m2 body surfaced) or placebo infusion. Results: After T3 administration, free T3 concentrations increased until reaching a plateau at 24–48 h (3.43, 3.20–3.84 vs. 1.74, 1.62–1.93 pg/ml; P 0.03) without side effects. Heart rate decreased significantly after T3 infusion (63, 60–66 vs. 69, 60–76 beats per minute; P 0.008). Plasma noradrenaline (347; 270–740 vs. 717, 413–808 pg/ml; P 0.009), N-terminal pro-B-Type natriuretic peptide (3000, 438-4005 vs. 3940, 528-5628 pg/ml; P0.02), and aldosterone (175, 152–229 vs. 231, 154–324 pg/ml; P 0.047) significantly decreased after T3 administration. Neurohormonal profile did not change after placebo infusion in the control group. After synthetic L-T3 administration, left-ventricular end-diastolic volume (142, 132–161 vs. 133, 114–158 ml/m2 body surface; P 0.02) and stroke volume (40, 34–44 vs. 35, 28–39 ml/m2 body surface; P 0.01) increased, whereas external and intracardiac workload did not change. Conclusions: In DC patients, short-term synthetic L-T3 replacement therapy significantly improved neuroendocrine profile and ventricular performance. These data encourage further controlled trials with more patients and longer periods of synthetic L-T3 administration

Indications of beta-adrenoceptor blockers in Takotsubo syndrome and theoretical reasons to prefer agents with vasodilating activity

Takotsubo syndrome (TTS) is estimated to account for 1–3% of all patients presenting with suspected ST-segment elevation myocardial infarction. A sudden surge in sympathetic nervous system is considered the cause of TTS. Nonetheless, no specific recommendations have been provided regarding β-blocking therapy. Apart from specific contra-indications (severe LV dysfunction, hypotension, bradycardia and corrected QT interval >500 ms), treatment with a β-blocker seems reasonable until full recovery of LV ejection fraction, though evidence is limited to a few animal studies, case reports or observational studies. In this review, we will reappraise the rationale for β-blocker therapy in TTS and speculate on the pathophysiologic basis for preferring non-selective agents with vasodilating activity over β1-selective drugs

Shape optimization of a curved duct with Free Form Deformations

The Free Form Deformation method was applied to a S-duct geometry to reduce total pressure losses and flow distortion. The deformation method was coupled with a multiobjective genetic algorithm to optimize the shape of a diffusing S-duct, which was previously investigated, both numerically and experimentally. During the optimization process, 200 deformed shapes were tested with steady-state CFD simulations and the performances were evaluated both in terms of total pressure losses and swirl angle at the outlet. It was obtained a Pareto front with a maximum total pressure losses reduction of 20% and a maximum swirl reduction of 10%. The two extreme points of the Pareto front were further investigated by transient Detached Eddy Simulations to assess also the impact of the optimization on the flow instability. Surprisingly, one of the solutions showed stable and stationary vortical structures. This is in strong contrast with the previous investigations of the flow field time history of the baseline configuration, which outlined strong oscillations of the flow field combined with a high increase of the distortion parameters in comparison with the time-averaged flow field

Chemical and spectroscopic characterization of humic acids extracted from the bottom sediments of a Brazilian subtropical microbasin

International audienceHumic substances (HS) perform a fundamental role in aquatic environments, exhibiting different levels of reactivity in retaining metal ions and organic pollutants. Also, they control the primary production of these ecosystems and act in the carbon sequestering process. In order to improve our understanding vis-à-vis the structural and functional features of HS from aquatic systems, this study aimed to chemically and spectroscopically characterize humic acids (HA) isolated from bottom sediment samples of a stream in a Brazilian subtropical microbasin by elemental analysis, and infrared (FT-IR), ultraviolet and visible (UV-Vis) and solid-state 13C nuclear magnetic resonance (CP-MAS 13C NMR) spectroscopies, thermogravimetry (TG), and scanning electron microscopy (SEM). Although all samples originated from the same environment, the data showed that the HA have distinct chemical and spectroscopic properties, and that the location and characteristics of the sampling points from which the sediments were collected played an important role in the differences observed. Furthermore, vascular plant matter is probably the main contributor to these samples