Spline-shaped ultra-wideband antenna operating in the ECC released frequency spectrum

A spline-shaped antenna for Ultra-Wideband (UWB) communications that operates in the Electronic Communications Committee (ECC) released band from 6 GHz up to 8.5 GHz is described. Selected simulated and measured data are reported to assess the achieved impedance matching over the whole band of interest, and the distortionless behavior as well as to show the omnidirectional radiation properties. This paper is a postprint of a paper submitted to and accepted for publication in Electronics Letters and is subject to Institution of Engineering and Technology Copyright. The copy of record is available at IET Digital Library

A SVM-Based Multi-Resolution Procedure for the Estimation of the DOAS of Interfering Signals in a Communication System

In this work, the use of a planar antenna system for the estimation of the directions of arrivals (DOAs) of multiple signals impinging on the receiver has been considered. Towards this end, an efficient multi-resolution method based on a SVM-classifier is proposed for determining a probabilitic map of the DOAs of the unknown interfering signals. Numerical results dealing with multiple interferers scenarios in noisy environments are provided in order to assess the feasibility as well as the capability of the proposed approach

A SVM-Based Three-Dimensional Multi-Resolution Approach for Biomedical Inverse Scattering Problems

In the last few years, microwave imaging techniques have been successfully used to provide the spatial distribution of tissues. In particular, because of the significant contrast of the dielectric properties between the normal tissue and the malignant tissue at microwave frequencies, microwave methods seem to be very promising diagnosis methods for the early cancer detection [1]

An Integration Between SVM Classifiers and Multi-Resolution Techniques for Early Breast Cancer Detection

Because of the high contrast between the dielectric properties of normal and malignant breast tissues at microwave frequencies, microwave imaging techniques seem to be very attractive diagnosis methods for cancer detection [1][2]. In such a framework, inverse scattering methods are very promising tools, but their practical application is strongly limited by the need of 3D reconstructions, high spatial resolutions, and fast processing. Recently, to reduce the high computational costs and to fit the real‐time requirements, inversion methods based on learning by example techniques have been proposed [3]. LBE approaches based on support vector machines (SVMs) [3] and neural networks (NNs) [4] have been satisfactorily applied in various and complex electromagnetic problems. When dealing with breast cancer detection, the inversion process is recast as a classification or regression problem where the unknowns are retrieved from the data (i.e., the electric field samples collected in an external observation domain) by approximating the unknown relation data‐unknowns through an off‐line data fitting procedure (training phase). Once the training procedure (performed once and off‐line) is completed, the characteristics of the malignant breast tissue are real‐time estimated in the testing phase. In such a work, the detection problem is addressed by integrating a SVM‐based classifier with an iterative multi‐zooming procedure. More in detail, a succession of approximations of a probability map of the presence of pathology is determined. At each step, the spatial resolution of the risk‐map is improved in a limited set of regions of interest (ROIs) defined at the previous zooming step and characterized by a greater value of the occurrence probability of a malignant tissue. The multi‐step procedure is stopped when a stationary condition on the probability and on the number of ROIs is reached. The achievable trade‐off between computational complexity and spatial resolution is preliminary assessed by discussing a selected set of numerical simulations concerned with both noiseless as well as corrupted data

The "Defibrillation Testing, Why Not?" survey. Testing of subcutaneous and transvenous defibrillators in the Italian clinical practice

Background: Defibrillation testing (DT) can be omitted in patients undergoing transvenous implantable cardioverter-defibrillator (T-ICD) implantation, but it is still recommended for patients at risk for a high defibrillation threshold and for ICD generator changes. Moreover, DT is still recommended on implantation of subcutaneous ICD (S-ICD). The aim of the present survey was to analyze the current practice of DT during T-ICD and S-ICD implantations.Methods: In March 2021, an ad hoc questionnaire on the current performance of DT and the standard practice adopted during testing was completed at 72 Italian centers implanting S-ICD and T-ICD.Results: 48 (67%) operators reported never performing DT during de-novo T-ICD implantations, while no operators perform it systematically. The remaining respondents perform it for patients at risk for a high defibrillation threshold. DT is never performed at T-ICD generator change. At the time of de-novo S-ICD implantation, DT is never performed by 9 (13%) operators and performed systematically by 48 (66%). The remaining operators frequently omit DT in patients with more severe systolic dysfunction. DT is not performed at S-ICD generator change by 92% of operators. DT is conducted by delivering a first shock energy of 65 J by 60% of operators, while the remaining 40% test lower energy values.Conclusions: In current clinical practice, most operators omit DT at T-ICD implantation, even when still recommended in the guidelines. DT is also frequently omitted at S-ICD implantation, and a wide variability exists among operators in the procedures followed during DT

Acute shock efficacy of the subcutaneous implantable cardioverter-defibrillator according to the implantation technique

Background: The traditional technique for subcutaneous implantable cardioverter defibrillator (S-ICD) implantation involves three incisions and a subcutaneous (SC) pocket. An intermuscular (IM) 2-incision technique has been recently adopted. Aims: We assessed acute defibrillation efficacy (DE) of S-ICD (DE ≤65 J) according to the implantation technique. Methods: We analyzed consecutive patients who underwent S-ICD implantation and DE testing at 53 Italian centers. Regression analysis was used to determine the association between DFT and implantation technique. Results: A total of 805 patients were enrolled. Four groups were assessed: IM + 2 incisions (n = 546), SC + 2 incisions (n = 133), SC + 3 incisions (n = 111), and IM + 3 incisions (n = 15). DE was ≤65 J in 782 (97.1%) patients. Patients with DE ≤65 J showed a trend towards lower body mass index (25.1 vs. 26.5; p = .12), were less frequently on antiarrhythmic drugs (13% vs. 26%; p = .06) and more commonly underwent implantation with the 2-incision technique (85% vs. 70%; p = .04). The IM + 2-incision technique showed the lowest defibrillation failure rate (2.2%) and shock impedance (66 Ohm, interquartile range: 57-77). On multivariate analysis, the 2-incision technique was associated with a lower incidence of shock failure (hazard ratio: 0.305; 95% confidence interval: 0.102-0.907; p = .033). Shock impedance was lower with the IM than with the SC approach (66 vs. 70 Ohm p = .002) and with the 2-incision than the 3-incision technique (67 vs. 72 Ohm; p = .006). Conclusions: In a large population of S-ICD patients, we observed a high defibrillation success rate. The IM + 2-incision technique provides lower shock impedance and a higher likelihood of successful defibrillation

Antioxidant properties of resveratrol and piceid on lipid peroxidation in micelles and monolamellar liposomes.

The antioxidant activities of trans-resveratrol (trans-3,5,4′-trihydroxystilbene) and trans-piceid (trans-5,4′- dihydroxystilbene-3-O-β-D-glucopyranoside), its more widespread glycosilate derivative, have been compared measuring their inhibitory action on peroxidation of linoleic acid (LA) and the radical scavenging ability towards different free radicals (such as DPPH) and radical initiators. It has been found that the two stilbenes have similar antioxidant capacity, while the comparison with BHT (2,6-di-tert-butyl-4-methylphenol) and α-tocopherol (vitamin E, vit. E), taken as reference, points out a slower but prolonged protective action against lipid peroxidation. Furthermore, piceid appears more efficacious than resveratrol as a consequence of the reaction of the latter with its radical form. The DSC profiles of phosphatidylcholine liposomes of various chain lengths, and EPR measurements of spin labelled liposomes demonstrated that the susceptible hydroxyl group of these compounds are located in the\ud lipid region of the bilayer close to the double bonds of polyunsatured fatty acids, making these stilbenes particularly suitable for the prevention and control of the lipid peroxidation of the membranes

Real-Time Tracking of Transceiver-Free Objects for Homeland Security

The increasing demand in homeland security speeds up the development of innovative and non‐invasive systems to localize and track moving objects in complex environments. In this paper the real‐time localization of transceiver‐free targets is addressed by means of learning by example methodology that exploits the received signal strength indicator available at the nodes of a wireless sensor network as input data. This approach uses neither dedicated sensors nor active devices put on the target to localize both idle and moving objects. The definition of a customized classifier during an offline training procedure enables the real‐time generation of a probability map of presence by processing the output of the support vector machine. Some selected experimental results validate the effectiveness of the proposed methodology applied in real scenarios

Dual-Band Spline-Shaped PCB Antenna for Wi-Fi Applications

In this letter, a dual-band PCB antenna suitable for Wi-Fi applications is described. The antenna geometry is modeled by means of a spline curve and a partial metallic ground plane. The proposed antenna is suitable for Wi-Fi bands and it guarantees good impedance matching conditions at the working frequencies centered at 2.448GHz and 5.512GHz, respectively. A prototype of the synthesized antenna, built on an Arlon substrate, is analyzed to assess the effectiveness of the proposed antenna model in terms of VSWR values as well as radiation patterns. (c) 2009 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works