In AL amyloidosis prognosis depends on the severity of heart dysfunction which is best assessed by natriuretic peptides (BNP and NT‐proBNP). However, their clearance relies on glomerular filtration rate (GFR) and their concentration increases with renal failure. We evaluated the diagnostic and prognostic performance of NT‐proBNP and BNP in 248 patients with AL amyloidosis with different degrees of renal failure. Patients were grouped according to GFR. Group 1 comprised 109 patients with GFR ≥60 mL/min/1.73 m², Group 2, 77 subjects with GFR <60 and ≥15 mL/min/1.73 m², and Group 3, 62 patients with GFR <15 mL/min/1.73 m². The ability of natriuretic peptides to detect heart involvement and to predict survival in the three groups was assessed. Decreasing eGFR required higher cutoffs of both NT‐proBNP and BNP for detecting heart involvement and predicting survival. Both natriuretic peptides were independent prognostic markers in Groups 1 and 2, whereas in Group 3 only BNP independently predicted survival. Natriuretic peptides are powerful and useful markers of cardiac dysfunction and prognosis, provided that eGFR is considered in interpreting their clinical meaning. BNP should be preferred in patients with end‐stage renal failure. Am. J. Hematol. 87:465–471, 2012.

The use of current probes for the injection of wide-band disturbance in electromagnetic compatibility applications requires their accurate characterization up to few gigahertz. While the representation of the current probe with a simple transformer is acceptable at low frequencies, the spectral content of fast signals requires models which are accurate even at gigahertz frequencies. This can be accomplished directly by measurements in the frequency domain (FD), making use of a S-matrix representation of the probe, or in the time domain (TD), recovering the transfer functions from the impulse responses measurement. Both techniques suffer limitations due to numerical and experimental problems; in particular, the FD approach leads to the solution of an inverse problem, with numerical instabilities in the high-frequency range, whereas the TD approach is not so accurate in the low-frequency range of the sought transfer function. The paper combines the two techniques to overcome these difficulties and achieve a better accuracy across the overall bandwidth. The characterization of a commercially available current probe allows comparison of numerical results with experimental measurements.

The use of electromagnetic (EM) fields for obstacle detection to aid mobility of visually impaired people is presented in this paper. The method proposed is based on the launch of EM pulses and on the measurement of the reflected signal which explores a region in front of the user of about 3 m. A laboratory system is set up, its performances (detecting the presence and the distance of obstacles) are investigated, and the measurements are compared with the data measured by an ultrasonic obstacle detection system. Results show that, with the EM system, all the obstacles tested (up to a minimum size of 3 cm × 3 cm, at a distance of 3 m) are correctly detected, as well as some specific targets (a chain, a pole, etc.) that are not visible by the ultrasonic system. The EM system has been tested in indoor and outdoor cluttered scenarios at the presence of real obstacles (single and multiple), and in all cases, it detects their presence with a signal-to-noise ratio ranging from 10 to 23 dB. Despite the use of a laboratory system, still not specifically designed for daily use, this paper demonstrates the possibility of adopting EM held pulses for obstacle detection, highlighting advantages with respect to ultrasonic systems and addressing future research activity to design an improved ad hoc EM system.

In this paper, a self-consistent model is developed of the propagation of an electromagnetic wave into a plasma region, based on the solution of the Maxwell-Boltzmann system of equations. The system is resolved using a finite-difference time-domain approach that gives as results the behavior of both the particle velocity distribution function and the electromagnetic fields. The method is applied to a simple situation in which a wave impinges on a plasma region, but can easily be extended to more complicated configurations.

This paper presents two test benches for the characterization of a plasma column used as a radiating element. In particular, the main parameters to be quantified are the efficiency of the plasma antenna, the turn-on time of the column, and the conductivity of the plasma. The first two parameters are evaluated by measuring the field radiated by the plasma antenna compared with that of an equivalent copper antenna. For the conductivity, a reflectometric technique is used, wherein the plasma column is inserted inside a waveguide. The accuracy of the method is limited by the ill-conditioned relationship between the reflection coefficient and the plasma conductivity; nevertheless, it is sufficient to subdivide the range of the conductivity values into three regions (i.e., low, medium, and high conductivities) to determine the best operating conditions of the antenna.

The possibility of using a surfaguide device as plasma source for plasma antenna application has been experimentally investigated. The surfaguide was optimized, realized and used for the ignition of a plasma column to be used as a radiating structure: the coupling with the radiated signal network and plasma antenna efficiency were measured showing that a surfaguide can be effectively used to create and sustain the plasma conductive medium. A plasma diagnostic technique was also developed to evaluate the plasma column length and plasma conductivity with respect to the power supplied. These measurements highlighted that plasma antenna properties are strongly affected by the pump signal and therefore this signal has to be optimized in order to have the highest conductivity.