Guided wave expansion in warped curvelet frames

Lamb wave testing for structural health monitoring (SHM) often relies on analysis of wavefields recorded through scanning laser Doppler vibrometers (SLDVs) or ultrasonic scanners. Damage detection and characterization with these techniques requires isolation of defect-induced reflections in the wavefield from the injected wave packet and from scattering events associated with structural features such as boundaries, rivets, joints, etc. This is a challenging task when dealing with complex structures and multimodal, dispersive propagation regimes, whereby various wave contributions in both the time/space and the frequency/wavenumber domain overlap. A new mathematical tool named warped curvelet frames (WCFs) is proposed to effectively decompose the recorded wavefields. The presented technique results from the combination of two operators, i.e., the curvelet transform (CT) and the warped frequency transform (WFT). The CT provides an optimally sparse representation of nondispersive wave propagators. Combining the CT with the WFT allows for a flexible analysis of multimodal wave propagation in dispersive media. Exploiting the spatial and temporal localization of curvelets, as well as the spectro-temporal adaptation of the analysis frame to the characteristics of each propagating mode, provided by frequency warping, a convenient decomposition of guided waves is achieved and relevant contributions can be effectively isolated. The proposed approach is validated through dedicated simulations and further tested experimentally to demonstrate the effectiveness of the method in separating guided wave modes corresponding to acoustic events in close spatial proximity.     

Clinal variation in the nuclear DNA of Europeans

Melatonin (N-Acetyl-5-methoxytryptamine) is a hormone secreted mainly by the pineal gland or epiphyse and in smaller amounts by the retina. It is biosynthesized from tryptophan, the critical enzymatic step depends upon N-Acetyl-transferase (NAT). The circadian rhythm of melatonin is the same in man and all the laboratory animals studied until now with nocturnal plasma concentrations 3-10 times greater than during daytime. The secretion and release of melatonin depend upon a large number of exogenous and endogenous factors as e.g. sex, age, pubertal stage, menstrual cycle, drugs, season.... Light is the major regulating factor which acts through the retino-hypothalamic tract. Melatonin is considered as a transducer of the light signal forwarding to the organism the information about day length (relative length of day and night). It is a time-clue provider used by the organism to adapt itself to its environment.     

Endothelium and bone marrow transplantation

Thrombotic complications may occur early after marrow transplantation and many data suggest that endothelial injury plays a pivotal role in their pathogenesis. Since plasma thrombomodulin and P-selectin are thought to be of value as markers of vascular endothelial cell membrane injury, we investigated their plasma concentration in bone marrow transplant patients aiming better to clarify the degree of endothelial involvement. Plasma thrombomodulin and P-selectin were monitored in 25 patients without thrombotic complications before transplant, on day 0 and weekly for 1 month thereafter, while in three patients who developed VOD monitoring continued until day +52. These proteins were in the normal range in all the uncomplicated patients and in two with reversible VOD, while they were always very high in the only patient who developed very severe and lethal VOD. In conclusion, we suggest that endothelial activation/damage occurs rarely in the course of BMT for hematological malignancies; we were able to document endothelial injury in only one patient with very severe thrombotic complication.     

Warped basis pursuit for damage detection using lamb waves

This paper presents a novel time-frequency procedure based on the warped frequency transform (WFT) to process multi-mode and dispersive Lamb waves for structural health monitoring (SHM) applications. The proposed signal processing technique is applied to time waveforms recorded at an array of scan points after waveguide excitation. The WFT is combined with a basis pursuit algorithm to extract the distance traveled by the ultrasonic waves even in the case of multi-modal dispersive propagation associated with broadband excitation of the waveguide. This is obtained through a decomposition of the acquired signals using dictionaries composed by optimized atomic functions which are designed to match the spectro-temporal structure of the various propagating modes. The warped basis pursuit (W-BP) analysis of several acquired waveforms results in distance signals that can be combined through classical beamforming techniques for acoustical source imaging purposes. A masking procedure is also proposed to suppress imaging noise. This approach is tested on experimental data obtained by broadband guided wave excitation in a 1-mm-thick aluminum plate with an artificially introduced through crack and tiny holes, followed by multiple waveguide displacement recording through a scanning laser Doppler vibrometer. Dispersion compensation, high-resolution source, and defect imaging are demonstrated even in domain regions that are not directly accessible for measurement.     

Percutaneous umbilical blood sampling in the management of immune thrombocytopenic purpura during pregnancy

Severe neonatal thrombocytopenia occurs in about 15% of deliveries from women with immune thrombocytopenic purpura (ITP). Conflicting data exist about the real usefulness of percutaneous umbilical blood sampling (PUBS) in evaluating the fetal platelet count. We report successful experience, using PUBS, in the management of 12 pregnant women with ITP.     

Impact of LER and Random Dopant Fluctuations on FinFET Matching Performance

Parameter variations pose an increasingly challenging threat to the CMOS technology scaling. Among the sources of variability, line-edge-roughness (LER) and random dopant (RD) fluctuations are significant in current technology nodes. In this paper, the impact of the LER and RD on the matching performance of FinFETs is investigated for the LSTP-32 nm node, where these devices represent an attractive alternative to the planar CMOS transistors. Line-edge-roughness contributions from the fin, top-, and side wall-gates of n- and p-channel FinFETs are compared by means of 2-D and 3-D technology computer-aided design (TCAD) simulations, performed with a quantum-corrected hydrodynamic model on large statistical ensembles. Correlations between geometrical roughness and resulting electrical parameters are analyzed to provide further insight into the impact of the LER. A noise analysis approach is adopted to evaluate the impact of RD fluctuations throughout the impurity concentration ranges of interest, providing a direct comparison with the line-edge-roughness contributions. The impact of the extension doping profile specifications on the LER- and RD-induced mismatch is investigated, highlighting the potential drawbacks of junction engineering.