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Dabigatran (DAB) is 80 % renally excreted. Glomerular filtration rate (GFR) estimation is recommended to evaluate the kidney function for DAB dosage adjusting. In this paper we report same results about evaluation of creatinine (CRE) GFR and cystatin-C (CYS) GFR in comparison with drug concentration in a group of patients treated with DAB. We considered 77 patients in which an evaluation of kidney function using CRE and CYS based GFR was performed. After GFR-CRE and GFR-CYS calculation these patients were classified as recommended by KDIGO guidelines. Moreover we evaluated the relationship between trough DAB concentration and GFR-CRE or GFR-CYS. We observed a satisfactory correlation between GFR-CRE and GFR-CYS ( $R=0.85$ ). Following KDIGO criteria, patients’ classification performed by using GFR-CRE or GFR-CYS was concordant in 52 (68 %) subjects and discordant in 25 (32 %). We observed an inverse relationship between trough DAB concentration versus GFR-CRE ( $R=-0.71$ ) and GFR-CYS ( $R=-0.79$ ). Results obtained in this study, although preliminary, suggested that, in this particular subset of patients, the determination of GFR-CYS can be a better renal function indicator than GFR-CRE. Moreover, we observed that GFR evaluation alone is not able to explain in a satisfactory manner, individual responses to dabigatran etexilate evaluated as a trough DAB concentration.

Achieving the minimum number of radiating elements in the active electronically scanned array synthesis represents a key problem in those applications where the power consumption, the weight, and the hardware/software complexity of the radiating system have a strong impact on the system cost. In this paper, a new method for the synthesis of planar, nonsuperdirective, maximally sparse, and steerable arrays is proposed and tested on several benchmarks available in the open literature. The method optimizes simultaneously the weight coefficients and sensor positions of a planar array without using global optimization schemes, properly exploiting convex optimization based algorithms. The resulting arrays are able to radiate a steerable beam pattern, satisfying a prescribed power mask and avoid to constraint the fitting of any a priori assigned reference field pattern. Several tests are presented to show the high efficiency in achieving the desired steerable radiation pattern with the minimum number of antenna elements.

An advanced version of the Contiguous Partition Method (CPM) aimed at designing subarrayed antenna arrays with control of the excitation amplitudes and phases only at the subarray level is presented. Starting from the quantized distribution of the amplitude weights yielded through the optimal excitation matching procedure based on the CPM, a successive phase-clustering of the array elements belonging to each CPM amplitude aggregation is carried out to further simplify the antenna architecture still keeping the wide angular sector steering property of the array. A set of representative results is reported and discussed to assess the features and potentialities of the proposed technique.

Fast and accurate diagnosis of array failure is important for the maintenance of array antennas. Locations of failing elements are usually detected using near field data, which may be polluted by noises. Most existing diagnosis methods assume non-impulsive noise in the measurement data. However, the practical measurement environment may contain impulsive noises, which has not been considered in existing methods. This work proposes to impose a penalty function in the residual between the measured and recovered near field. The impulsive noise in the near field data can then be suppressed by using an appropriate function as the penalty function. Furthermore, minimum lp-norm is imposed on the excitation vector. The condition imposed on the noise and the minimum lp-norm constraint on the excitation vector constitutes an optimization problem, which is solved using the unsupervised support vector regression. The proposed method is more accurate than existing methods when impulsive noise presents in the near field data, and it is able to deal with a wide range of number of failing elements by adjusting the value of p. Numerical results are presented to show the advantages of the proposed method and to study the choice of p.

The paper deals with a new measurement method for through-the-wall detection and tracking of hidden targets (e.g. human bodies in rescue missions) in two-dimensional scenes, by using radiofrequency signals. In particular, the method is based on a multisensor system and exploits an advanced imaging technique, which takes advantages from a regularized linear inversion scheme. Several numerical tests are conducted to assess the performance and capabilities of the method; satisfying values of the difference between estimated and nominal target position are experienced for different investigation domains, number of targets and signal-to-noise ratios. Moreover, experiments in actual measurement conditions and involving a prototype of the multisensor system (based on eleven antennas operating both as transmitting and receiving elements) are also presented, which show the reliability of the method as well as the effectiveness of the implemented measurement strategies.

In this paper, the synthesis of sparse time-modulated linear arrays with minimum number of elements and controlled harmonic radiations is investigated. The proposed iterative approach based on a particle swarm optimization is aimed at flnding the array conflguration with the minimum number of elements and the optimal pulse sequence that afiords a beam pattern with the same features of a reference one also limiting the amount of sideband radiations under a speciflc threshold. A set of representative numerical examples is discussed to assess the efiectiveness and the reliability of the proposed approach.

A deterministic and effective strategy to reduce as much as possible the number of amplitude controls points in large arrays is herein proposed, and applied to cases of practical interest. The proposed strategy exploits two important concepts: the first one, coming from a special class of aperiodic tiling, and the second one based on NuFFT – Non uniform Fast Fourier Transform – techniques. The first one allows designing innovative front-end architectures made of a reduced number of control points, while NuFFT algorithms lead to computationally effective synthesis procedures. The overall results and design guidelines allow to achieve simplified beamforming networks derived from aperiodic tilings, and to know the performances that can be achieved using this approach, particularly in case of low sidelobe requirements. To confirm the usefulness of the proposed tools, numerical examples are discussed. Conclusion follows.

Radio Frequency Energy harvesting is a research topic of increasing interest, related to sustainability, which could become a promising alternative to existing energy resources. The paper will show all the activities addressed to design a wideband system to recover wideband energy from electromagnetic sources present in the environment. The main idea is to develop battery-free wireless sensors able to capture the available energy into the mentioned bandwidth. The flnal goal is to realize self-powered Wireless Networks based on Ultra Lower Power | ULP sensors minimizing the need of dedicated batteries. This last feature is particularly attractive in difierent kind of applications, ranging from military to civil cases. A flrst system prototype is shown and discussed. Conclusion follows.

Photonic sensor networks are exploited to increase resilience of large phased arrays for radar and space applications. The network is embedded in the phased array front end to continuously enable easy and real-time control of the system components. The photonic sensors are able to measure amplitude and phase of the actual electromagnetic field distribution on the array aperture. The photonic network provides an estimation of failure/calibration errors and allows the minimization of the mismatch between the actual pattern and the reference one. The feedback system dynamically acts on the weights of the beamforming network (BFN), thanks to accurate and effective synthesis methods. Preliminary results concerning the overall system design, the possibility to integrate the photonic sensor inside the active radiating elements, and the capability to accurately correct undesired failure are reported.

The design of sparse arrays able to radiate focused beam patterns satisfying a given upper-bound power mask with the minimum number of sources is a research area of increasing interest. The related synthesis problem can be formulated with proper constraints on the cardinality of the solution space, i.e., its l0-norm. Unfortunately, such a nonconvex constraint requires to solve an NP-hard problem. Interesting ideas to relax the above constraint in a convex way have been successfully proposed. A possible solution is based on the minimization of the l1-norm. This strategy is not always able to achieve a maximally sparse solution. In the following, an innovative synthesis scheme that optimizes both excitation weights and sensor positions of an array radiating pencil beam-patterns is discussed. The solution algorithm is based on sequential convex optimizations including a reweighted l1 -norm minimization. Numerical tests, referred to benchmark problems, show that the proposed synthesis method is able to achieve maximally sparse linear arrays, also compared to the best results reported in the literature, obtained by means of global optimization schemes.

The need to reduce the number of active elements in radar arrays claims for developing new synthesis approaches able to reduce the control points, i.e., the number of transmit/receive modules (TRM) needed to fulfill the design constraints, is presented. As the large part of the TRM costs are related to the active parts (HPA-high power amplifier), a hybrid method for reducing the number of amplitude controls is proposed. This allow the design of new array architectural solutions where the scanning capabilities only rely on phase controls.

The problem of developing alternative methods for large arrays indoor testing is discussed. The key point is to generate plane waves across the antenna aperture such to simulate an incoming signal from the far field zone. The main contribution of this communication (with respect to previous publications from the same authors) deals with the realization of a plane wave generator over a 2D antenna under test domain.

Uniform amplitude sparse arrays have recently gained a renewed interest and a number of synthesis techniques, mainly based on global optimization algorithms, have been presented. In this paper, after a discussion about the expected characteristics of such arrays, a simple deterministic approach for the case of pencil beams patterns is proposed and discussed. The approach, which outperforms previous synthesis techniques, takes inspiration from existing (not well-known) density taper procedures to develop a two stages synthesis where the first step is solved in a new closed analytical form, while the second one just requires local refinements or fast 1-D optimizations. As a consequence, the proposed approach avoids the need of multidimensional global optimization procedures and the inherent possibly prohibitive computational costs. Notably the first step, which also exhibits an improved flexibility with respect to other analytical techniques, already outperforms previous approaches in a number of cases of interest. Several numerical results confirm the effectiveness and usefulness of the proposed tools.

In many diagnostics and imaging applications intensity only measurements of the diffracted field are available. Hence, it is of interest to develop procedures able to solve the underlying inverse scattering problem under these conditions. In this paper, we introduce an approach in which the geometrical and electromagnetic properties of unknown complex targets are reconstructed from the squared amplitudes of the diffracted fields. The approach relies on some preliminary considerations on the spatial bandwidth of the diffracted intensities which allow one to fix rules to effectively measure the data and on an alternative formulation of the electromagnetic scattering that lowers the ‘degree of non-linearity’ of the relationship among the electric features of the targets and the fields. The proposed procedure is tested against benchmark experimental data in the microwave frequency range and the obtained results confirm the possibility of achieving faithful quantitative images of unknown targets from phaseless...

With reference to inverse scattering problems, two different integral equation models belonging to the class of source-type integral equations are reviewed, discussed, and properly compared. In particular, starting from the concept of degree of nonlinearity of the scattering problem, universal plots and useful convenience maps are derived and exploited to foresee which is the most convenient integral equation model to adopt for modeling the scattering phenomena at hand. Numerical examples, dealing with both synthetic and experimental data, are reported and discussed. The results fully confirm the theoretical analysis.

A suitable deterministic partitioning of large planar arrays in two kinds of properly shaped subarrays is shown to improve performances in terms of side-lobes peaks, directivity and aperture efficiency with respect to other existing solutions. The application of this simple idea to the case of large planar arrays with a reduced number of control points, useful in satellite applications, is demonstrated.

—A deterministic method for detecting faulty elements in phased arrays is proposed and tested against experimental and numerical data. The solution approach assumes as input the amplitude and phase of the near-field distributions and allows to determine both positions and currents of radiating elements. The corresponding non linear inverse problem is properly solved by exploiting the distributional approach, which allows to cast the initial problem to the solution of a linear one, whose solution is made stable by adopting a proper regularization scheme based on the Truncated Singular Value Decomposition tool. The results fully confirm accuracy of the proposed technique.

A flexible approach for the synthesis of sparse arrays able to radiate plane waves in near-zone is proposed. In particular, the array dimension, the array element positions, and their weights are determined such to achieve the desired goal. Unlike existing techniques, the proposed one completely avoids the need for global optimizations, thus saving computational time and costs. Numerical examples, confirming potentialities of the proposed tools and algorithms, are discussed.

Starting from the concept of "degree of non-linearity" of the relationship amongst unknown parameters and scattered fields, we discuss how knowledge of the geometrical features of the targets favorably affects the solution of inverse scattering problems. The same concept is also exploited to optimize the contrast source-extended Born (CS-EB) model, resulting in the optimized CS-EB (O-CS-EB) inversion approach, which remarkably reduces false solutions occurrence. Then, a two-steps approach is proposed as a reliable and effective inversion strategy. The first step consists in retrieving the shape of the targets using the linear sampling method, while in the second step, the estimated shapes and the O-CS-EB are exploited to reconstruct the permittivity profile. The approach has been tested against experimental data, showing that very accurate reconstructions are achieved from monochromatic data.

The problem of synthesizing "optimal" sum and difference patterns subject to arbitrary sidelobe bounds by means of a simple feeding network is dealt with. It is shown how a hybrid optimization procedure properly acting on both clustering into subarrays and excitations of these latter greatly improves performances of known feeding architectures with respect to existing procedures. Results of the proposed technique, which significantly outperform existing methods, renew the interest of these simple feeding architectures, and emphasize the effectiveness of this kind of hybrid procedures exploiting the convexity of the problem with respect to a part of the unknowns

Most global optimization based synthesis procedures act in essentially the same way on all the involved variables. In this paper, it is theoretically discussed and numerically emphasized how explicit exploitation of the convexity of the problem with respect to a part of the degrees of freedom (when available) allows to achieve increased performances with respect to previous results, and to develop new interesting design solutions. Examples are presented for the synthesis of both sum and difference patterns by using nonuniformly spaced arrays and for the so called "optimal compromise amongst sum and difference patterns." Finally, the proposed approach is exploited in developing effective design solutions (based on the concept of interleaved arrays) to the problem of achieving very flexible antennas while using simple feeding networks. As an example, array antennas capable to radiate two different beams with individually steerable patterns, or to perform jammer rejection at the physical layer or even to realize a "flat-top" beam pattern are synthesized and presented

A proper extension of the contrast source extended Born model, recently introduced in the two-dimensional scalar case, is proposed to establish a novel full-wave inversion method for nonlinear vectorial three-dimensional scattering problems. In particular, a suitable auxiliary function, embedding the parameters of the unknown targets, is introduced as fundamental unknown of the inverse problem instead of the widely used contrast function. Numerical examples confirm effectiveness and reliability of the proposed inversion approach, which also favorably compares with other methods previously known in the literature

A new measurement method for through-the-wall detection of life signs is proposed hereinafter. The method analyzes the phase modulation that a sinusoidal signal, generated by means of a proper continuous-wave microwave transceiver, undergoes when reflected by the chest periodic displacement associated with breathing. It takes advantage of a suitable spatial smoothing decorrelation strategy applied to the traditional algorithm for MUltiple SIgnal Classification (MUSIC), mandated to single out the spectral components of the received phase signal. With respect to other measurement solutions, already available in the literature and exploiting either the traditional discrete-time Fourier transform, or matched filters, or standard singular value decomposition, the proposed method assures competitive performance in detecting the respiratory activity from the received microwave signal and effective noise/clutter rejection. The results of several tests both in simulated and actual scenarios, i.e., people behind walls in a furnished room, prove the efficacy and reliability of the method also in the presence of critical measurement conditions such as low signal-to-noise ratios and chest displacement associated with shallow breathing.

With reference to the case of TM data, in this paper we test the reconstruction capabilities of a recently proposed inverse scattering approach: the contrast source extended Born (CS-EB) inversion method. By relying on a suitable rewriting of the scattering equations, the CS-EB is claimed to be particularly effective whenever losses are present in the background medium and/or in the unknown scatterers. Here, by taking advantage of the Marseille data set concerning lossless inhomogeneous targets in free space, we show the effectiveness of the CS-EB inversion method also in the lossless case. In order to take advantage in a simple fashion of the available multifrequency information, data are processed within a frequency hopping scheme and suitable regularization schemes are exploited at each frequency. Moreover, in order to reduce the computational burden as well as the overall difficulty, the limited bandwidth properties of scattered fields are exploited by means of some simple processing to achieve a preliminary estimation of the region wherein the scatterers are located.

The human X chromosome has a unique biology that was shaped by its evolution as the sex chromosome shared by males and females. We have determined 99.3% of the euchromatic sequence of the X chromosome. Our analysis illustrates the autosomal origin of the mammalian sex chromosomes, the stepwise process that led to the progressive loss of recombination between X and Y, and the extent of subsequent degradation of the Y chromosome. LINE1 repeat elements cover one-third of the X chromosome, with a distribution that is consistent with their proposed role as way stations in the process of X-chromosome inactivation. We found 1,098 genes in the sequence, of which 99 encode proteins expressed in testis and in various tumour types. A disproportionately high number of mendelian diseases are documented for the X chromosome. Of this number, 168 have been explained by mutations in 113 X-linked genes, which in many cases were characterized with the aid of the DNA sequence.