Polarimetric distance-dependent models for large hall scenarios

A comprehensive polarimetric distance-dependent model of the power delay profile (PDP) and path gain is proposed. The model includes both specular multipath components (SMCs) and dense multipath components (DMC), the latter being modeled with an exponential and power law. The parameters of the model were estimated from polarimetric measurements of a large hall radio channel under line-of-sight (LOS) conditions at 1.3 GHz with a dedicated procedure. The validity and robustness of the proposed approach are provided by the good agreement between the polarimetric data and models for the investigated transmitter-receiver distance range. Furthermore, the description of the radio channel with path loss models is discussed for cases where the DMC is included, and a two-step method to compute the path loss characteristics directly from the measured data is developed. The results of this contribution highlight the fact that a complete polarimetric description of all propagation mechanisms and related path loss models is desired to design faithful polarimetric radio channel models

Ergogenic and Physiologic Effects of tDCS on Maximal Aerobic Performance: Protocol Description

Physical performance and means to improve it have been studied for a long time. While there are numerous variables affecting one individual’s aerobic capacity, central mechanisms are known to be strong restrictors. These include the output generated by the motor cortex but also the mental fatigue or the perceived exertion. One way to act on these cortically mediated processes is through transcranial direct current stimulation (tDCS), a non-invasive neuromodulation method using weak electrical currents to modify neural excitability. Previous studies showed that tDCS applied over the primary motor cortex can improve maximal performance in cycling as well as sometimes decrease ratings of perceived exertion. However, none of these studies controlled important performance-related physiological parameters such as the evolution of oxygen uptake or blood lactate levels. Additionally, no study investigated the ergogenic effects of tDCS in runners. Therefore, we propose a new protocol to investigate the effects of motor tDCS on treadmill running performance as measured by time-to-exhaustion trials. This randomized double-blind sham controlled trial will compare the effects of active tDCS as compared to sham on time to exhaustion. Psychophysiological responses to exercise, including rating of perceived exertion, oxygen uptake, heart rate, and blood lactate concentration, will be measured continuously during the time to exhaustion trials. These runs will be performed at 90% of the individual maximal aerobic speed. This will be the first of its kind trial investigating the ergogenic and physiologic effects of tDCS on running performance. The results will provide further insight into tDCS mechanisms of action

The pulmonary autograft after the Ross operation : results of 25 year follow-up in a pediatric cohort

Progressive autograft dilation and need for later reoperation remain major concerns of the Ross procedure. The study investigates the clinical outcome after the Ross operation, including a longitudinal analysis of autograft dimensions over 25 years. From November 1991 to April 2019, 137 patients underwent a Ross procedure at the University Hospitals of UCL (Université catholique de Louvain)-Brussels and Ghent. Inclusion criteria were less than or equal to 18 years of age and pulmonary autograft implantation by root replacement. Outcome focused on survival, reoperation rate, and autograft size evolution through linear mixed-model analysis. A Ross or Ross-Konno operation was performed in 110 (80%) and 27 (20%) patients at a median age of 10.4 (interquartile range [IQR], 4.7-14.3) years and 0.5 (IQR, 0.04-5.2) years, respectively. Overall 10-year and 20-year survival was 87% ± 3% and 85% ± 3%, respectively, but was 93% ± 3% for isolated Ross patients. Right ventricular outflow tract-conduit exchange was required in 20.3%, whereas autograft-related reoperation was performed in 14 (10.7%) patients at a median interval of 14 (IQR, 9-16) years, for aortic regurgitation (n = 2) and autograft dilation (n = 12). Autograft z-values increased significantly at the sinus and sinotubular junction (STJ) compared with the annulus (annulus = 0.05 ± 0.38/y, sinus = 0.14 ± 0.25/y, STJ = 0.17 ± 0.34/y; P = .015). The z-value slope for autograft dimensions was significantly steeper for Ross-Konno vs Ross patients (annulus: P = .029; sinus: P < .001; STJ: P = .012), and for children having aortic arch repair (annulus: P = .113, sinus: P = .038; STJ: P = .029). The Ross operation offers children requiring aortic valve replacement an excellent survival perspective, with an acceptable risk of autograft reoperation within the first 25 years. Contrary to the autograft annulus, dilation of the sinus and STJ size is of concern. Closer surveillance of autograft dimensions might be required in patients who underwent a Ross-Konno procedure or aortic arch reconstruction

Polarimetric properties and modeling of the power delay profile in large hall scenarios

A full-polarimetric model of the power delay profile (PDP) is proposed in a large hall scenario and validated with polarimetric measurements of a large open hall radio channel under Line-of-Sight conditions at 1.3 GHz. The measured radio channels were processed by the high-resolution parametric estimator RiMAX to estimate both the polarimetric specular multipath components (SMC) and dense multipath components (DMC). The model of the full-polarimetric distance-dependent PDP was derived from which the depolarization mechanisms are presented. In addition, it is demonstrated that the room electromagnetics theory applies to our scenario across all polarization links. The validity of the proposed model is provided by the good agreement between the polarimetric data and models. The results of this contribution highlight the fact that a complete polarimetric description of all propagation mechanisms is desired in polarimetric radio channel models

Clinical experience with the ATS 3f Enable® Sutureless Bioprosthesis

Objective: The ATS 3f Enable® Bioprosthesis is a self-expanding valve with a tubular design that allows for decreased leaflet stress and preservation of aortic sinuses. We report the midterm results of a prospective, multicenter clinical study evaluating the safety and efficacy of this stented bioprosthesis in patients undergoing isolated aortic valve replacement with or without concomitant procedures. Methods: A total of 140 patients (mean age: 76±6years; 63% of patients in New York Heart Association (NYHA) stage III-IV) received the ATS 3f Enable® Bioprosthesis in 10 European centers between March 2007 and December 2009. The total accumulated follow-up is 121.8 patient-years. Results: Valve implantation resulted in significant improvement of patients' symptoms. Mean systolic gradient was 9.04±3.56 and 8.62±3.16mmHg with mean effective orifice area of 1.69±0.52 and 1.67±0.44 at 6 months and 1 year, respectively. No significant transvalvular aortic regurgitation was observed. Early complications included three major paravalvular leaks (PVL; 2.1%) resulting in valve explantation and one thrombo-embolic (0.7%) event. All, but one, of the early PVLs were evident intra-operatively with the medical decision made not to reposition or resolve immediately. Late adverse events included three explantations (2.5% per patient-year): one due to PVL and two due to endocarditis. There was an additional case of late endocarditis (0.8% per patient-year) that resolved by medical management. No structural deterioration, valve-related thrombosis or hemolysis was documented. Conclusions: The sutureless valve implantation technique is feasible and safe with the ATS 3f Enable Bioprosthesis. Valve implantation resulted in excellent hemodynamics and significant clinical improvement. Overall, these data confirm the safety and clinical utility of the Enable® Bioprosthesis for aortic valve replacemen

Myocardial infarction primes autoreactive T cells through activation of dendritic cells

Peripheral tolerance is crucial for avoiding activation of self-reactive T cells to tissue-restricted antigens. Sterile tissue injury can break peripheral tolerance, but it is unclear how autoreactive T cells get activated in response to self. An example of a sterile injury is myocardial infarction (MI). We hypothesized that tissue necrosis is an activator of dendritic cells (DCs), which control tolerance to self-antigens. DC subsets of a murine healthy heart consisted of IRF8-dependent conventional (c) DC1, IRF4-dependent cDC2, and monocyte-derived DCs. In steady state, cardiac self-antigen alpha-myosin was presented in the heart-draining mediastinal lymph node (mLN) by cDC1s, driving the proliferation of antigen-specific CD4(+) TCR-M T cells and their differentiation into regulatory cells (Tregs). Following MI, all DC subsets infiltrated the heart, whereas only cDCs migrated to the mLN. Here, cDC2s induced TCR-M proliferation and differentiation into interleukin-(IL)-17/interferon-(IFN) gamma-producing effector cells. Thus, cardiac-specific autoreactive T cells get activated by mature DCs following myocardial infarction

Exploring the Mutational Landscape of Isolated Congenital Heart Defects: An Exome Sequencing Study Using Cardiac DNA

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