This article presents a review of air-coupled ultrasonics employed in the characterization or nondestructive inspection of industrial materials. Developments in air-coupled transduction and ...electronics are briefly treated, although the emphasis here is on methods of characterization and inspection, and in overcoming limitations inherent in the use of such a tenuous sound coupling medium as air. The role of Lamb waves in plate characterization is covered, including the use of air-coupled acoustic beams to measure the elastic and/or viscoelastic properties of a material. Air-coupled acoustic detection, when other methods are employed to generate high-amplitude sound beams is also reviewed. Applications to civil engineering, acoustic tomography, and the characterization of both paper and wood are dealt with here. A brief summary of developments in air-coupled acoustic arrays and the application of air-coupled methods in nonlinear ultrasonics complete the review. In particular, the work of Professor Bernard Hosten and his collaborators at Bordeaux is carefully examined.
Introduction/objectives
Accurate interpretation of DFS70 (dense fine speckled 70) and mixed antinuclear antibodies (ANAs) patterns can be challenging using conventional HEp-2 immunofluorescence (IIF) ...method. We evaluated a novel HEp-2 IIF substrate (HEp-2 ELITE/DFS70-KO) composed of a mixture of engineered HEp-2 devoid of the DFS70 autoantigen and conventional HEp-2 cells. The study assessed the utility of the new substrate in ANA screening and its advantages.
Method
One thousand and five consecutive routine samples sent for ANA screening were tested on both standard HEp-2 and the HEp-2 ELITE DFS70 KO substrates (ImmuGlo ANA HEp-2 and HEp-2 ELITE/DFS70-KO, Trinity Biotech, Buffalo, NY). Anti-DFS70 antibody specificity was additionally determined by immunoblot (IB). Clinical and serological data were included in the analysis of the overall impact of the novel HEp-2 substrate on DFS pattern interpretation.
Results
Of the 22 cases suspected as positive for DFS pattern alone or in combination with homogeneous or speckled patterns on conventional HEp-2 cells, 17 were interpreted with a higher accuracy using the new HEp-2 ELITE method as positive for DFS70 (monospecific DFS70 (10), mixed DFS70 (7)), speckled (3), and DFS (2) patterns.
Conclusions
The new substrate was not only useful in deciphering unclear mixed ANA patterns but also highly sensitive in detecting DFS70 pattern in comparison to the DFS70 positivity obtained using IB.
Objectives: A defined role for natural killer (NK) cells and their activating receptors in autoimmunity has not been clearly established. The aim of this study was to evaluate the levels of the ...CD3-CD56+ NK cells and their expression of receptors and co-receptors in the peripheral blood of patients with systemic autoimmune disorders.
Methods: Thirty-four subjects with systemic sclerosis (SSc), 14 with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), 14 with systemic lupus erythematosus (SLE), and 14 healthy donors were studied. The activating receptors NKp46, NKp44, NKp30, NKG2D, and DNAM-1 and the co-receptors NTB-A and 2B4 were analysed by flow cytometry on peripheral blood NK cells.
Results: In SSc, AAV, and SLE we detected a significant decrease in the percentage of CD3-CD56+ NK cells compared to healthy controls. No differences in the expression of NKp46, NKp44, and NKp30 were identified. On the contrary, NKG2D and DNAM-1 expression was decreased in SLE, but not in SSc and AAV, NTB-A was decreased in SLE, and 2B4 in both SLE and SSc. No differences were detected between active and inactive SLE patients. In SSc, only patients affected by pulmonary arterial hypertension (PAH) and interstitial lung disease (ILD) had a low expression of DNAM-1, 2B4, and NKp30.
Conclusions: These data demonstrate that patients with different systemic autoimmune diseases differ in the expression of activating receptors and co-receptors on CD3-CD56+ NK cells. The down-regulation of receptors and co-receptors in SSc with lung involvement suggests their possible role in this manifestation of the disease.
► We investigate plate wave transmission and reflection past rectangular obstructions. ► We compare experiments to original boundary element method calculations. ► Theory matches experiment over a ...range of frequencies and two different geometries. ► Application of model to spacecraft leak location.
This paper examines guided wave transmission characteristics of plate stiffeners and their influence on the performance of acoustic noise source location. The motivation for this work is the detection of air leaks in manned spacecraft. The leaking air is turbulent and generates noise that can be detected by a contact-coupled acoustic array to perform source location and find the air leak. Transmission characteristics of individual integral stiffeners are measured across a frequency range of 50–400kHz for both high and low aspect-ratio rectangular stiffeners, and comparisons are made to model predictions which display generally good agreement. It is demonstrated that operating in frequency ranges of high plate wave stiffener transmission significantly improves the reliability of noise source location in the plate. A protocol is presented to enable the selection of an optimal frequency range for leak location.
We have developed an ultrasonic array sensor useable for locating air leaks in manned spacecraft and have found that this sensor locates leaks in a 1-m2 plate to within 2cm. The sensor consists of a ...63-element multiplexed array plus a reference element, all constructed from a single PZT disc and a printed circuit board. Cross-correlations of signals from the array elements with signals from the single reference element provide a measurement of the leak noise passing through the spacecraft skin under the array. A spatial Fourier transform reveals the dominant direction of propagation. Triangulation from multiple sensor locations can be used to find the source of the leak.
A method is devised and demonstrated for the detection of disbonds in E-glass-epoxy/end-grain balsa core composites. Guided acoustic waves are exploited in an approach that leads to positive ...identification of disbonds in these complex marine composites. The method uses the fact that a propagating Lamb wave in the 3-mm glass-epoxy facesheet composite will exist only when a disbond (even a disbond in partial contact) is present at the location of the incident acoustic beam. The resulting leaky wave field in the fluid is then detected and monitored over the scanned area, producing a C-scan of the interface with clear discrimination between bonded areas and disbonds. Numerical evaluations of the received transducer voltage corresponding to different interface conditions are compared with the experimental measurements. A theoretical calculation based on prior work predicts accurately the results of several experiments on a variety of samples with different disbond conditions.
The well known zero in the group velocity of the first-order symmetric (S
1) plate wave mode has been exploited in air-coupled ultrasonic imaging to obtain significantly higher sensitivity than can ...be achieved in conventional air-coupled scanning. At the zero group velocity point at the frequency minimum of the S
1 mode, a broad range of wavenumbers couple into the first-order symmetric mode at nearly a constant frequency, greatly enhancing transmission at that frequency. Coupled energy remains localized near the coupling point because the group velocity is zero. We excite the mode with a broadband, focussing, air-coupled transducer at the frequency of the zero group velocity point in the S
1 mode. By exploiting the efficient coupling at the zero group velocity frequency, we have easily imaged a single layer of Scotch tape attached to a 6.4-mm thick Plexiglas plate and 3.2-mm Teflon inserts in a composite laminate.
Circulating endothelial progenitor cells (EPCs) are bone marrow-derived cells, contributing to endothelial cell regeneration of injured vessels as well as neovascularization of ischemic lesions. EPC ...levels and function are inversely correlated with cardiovascular risk factors, can predict the occurrence of adverse events and atherosclerotic disease progression. Ischemia and inflammation are the primary triggers for EPC mobilization and homing, however, vascular trauma, as it occurs during surgical procedures, has been demonstrated to stimulate EPC mobilization even in absence of tissue ischemia. The effect of angioplasty on EPCs is not well defined, mainly because of the different and sometimes contrasting clinical results, due to low numbers of patients enrolled and to lack of standardization in evaluating EPCs. Aim of this review is to report recent results on the effect of EPC mobilization and homing after angioplasty, attempting to summarize them in a comprehensive model. The effect on EPCs of different kind of stents and the potential use of new stents able to attract EPCs will be also described. Results obtained in patients undergoing angioplasty in different vascular districts (coronary, peripheral and carotid) will be shown, together with the correlation between circulating progenitor cells and restenosis.
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