Laser generation of Rayleigh and Lamb waves for ultrasonic nondestructive testing

Laser ultrasonics has been the focus of several research efforts over the last two decades. The main advantage of the technique is its noncontact nature which alleviates the problem of sensor coupling inherent in conventional techniques. However, laser ultrasonics has some limitations When operated in the thermoelastic regime, where no damage is inflicted on the surface of the specimen, the signal-to-noise ratio (SNR) is very small, particularly when compared with conventional piezoelectric generation.[1] Several authors have proposed increasing the SNR by producing a source with spatial periodicity designed to enhance a particular wavelength. Royer and Dieulasaint [2] have used a periodic mask, Wagner et al [3] have used a lenticular array, Vogel [4] and Berthelot and Jarzynski [5] have used an array of optical fibers. Cielo et al. [6] increased the SNR by increasing the displacement by geometrical focusing. They detected the displacement of surface waves at the center of an anular source and demonstrated that it was 20 times greater than that of a spot source

Sound propagation over uneven ground and irregular topography

The goal of this research is to develop theoretical, computational, and experimental techniques for predicting the effects of irregular topography on long range sound propagation in the atmosphere. Irregular topography here is understood to imply a ground surface that is not idealizable as being perfectly flat or that is not idealizable as having a constant specific acoustic impedance. The interest of this study focuses on circumstances where the propagation is similar to what might be expected for noise from low-attitude air vehicles flying over suburban or rural terrain, such that rays from the source arrive at angles close to grazing incidence. The activities and developments that have resulted during the period, August 1986 through February 1987, are discussed

Sound propagation over uneven ground and irregular topography

Theoretical, computational, and experimental techniques were developed for predicting the effects of irregular topography on long range sound propagation in the atmosphere. Irregular topography is understood to imply a ground surface that: (1) is not idealizable as being perfectly flat, or (2) that is not idealizable as having a constant specific acoustic impedance. The focus is on circumstances where the propagation is similar to what might be expected for noise from low altitude air vehicles flying over suburban or rural terrain, such that rays from the source arrive at angles close to grazing incidence

Sound propagation over uneven ground and irregular topography

The acoustic impedance of the surface coverings used in the laboratory experiments on sound diffraction by topographical ridges was determined. The model, which was developed, takes into account full wave effects and the possibility of surface waves and predicts the sound pressure level at the receiver location relative to what would be expected if the flat surface were not present. The sound pressure level can be regarded as a function of frequency, sound speed in air, heights of source and receiver, and horizontal distance from source to receiver, as well as the real and imaginary parts of the surface impedance

Assessment of soil quality using bioaccessibility-based models and a biomarker index

Bioavailability in heterogeneous media such as soils is a multi-factorial concept which ranges from soil chemistry to toxicity. The complexity of this factor has been tackled by various studies pinpointing its relevancy for laboratory to field extrapolation of toxicity data. As contaminant bioavailability on these sites is virtually unknown, a global assessment of this issue has been conducted on soils impacted by antitank firing from a Canadian Range and Training Area (RTA) and contaminated by energetic materials (EM) and metals. Yet, the descriptive results acquired from this survey require further in-depth analysis so as to enhance understanding of soil health status. Statistical models as well as an index integrating biomarker responses were derived from this database and are proposed as diagnostic, explanatory and possibly predictive tools for soil bioavailability and quality assessment. Relationships associating bioaccessible contaminant levels to soil properties allowed to clarify contaminant behaviour in energetic material (EM)-contaminated soils. Likewise, models expressing biomarker responses as a function of bioaccessible contaminant concentrations contributed to identify the contaminants causing toxicity in earthworms and to the comprehension of those toxic effects. The index of biomarker response was adapted from similar concepts applied in the aquatic environment and is an original contribution to terrestrial sites. The biomarker index data were in agreement with soil contamination profiles and represent therefore an interesting tool for soil quality appraisal. Such tools also offer a promising potential for the management of contaminated soils.Peer reviewed: YesNRC publication: Ye

A combination of methotrexate and zoledronic acid prevents bone erosions and systemic bone mass loss in collagen induced arthritis

Introduction Osteoclasts play a key role in the pathogenesis of bone erosion and systemic bone mass loss during rheumatoid arthritis (RA). In this study, we aimed to determine the effect of methotrexate (MTX) and zoledronic acid (ZA), used alone or in combination, on osteoclast-mediated bone erosions and systemic bone mass loss in a rat model of collagen induced arthritis (CIA). We hypothesized that MTX and ZA could have an additive effect to prevent both bone erosion and systemic bone loss. Methods Arthritis was induced in 64 female Sprague-Dawley rats. After the clinical onset of CIA, rats were assigned to treatment with MTX (1 mg/kg/week), ZA (100 μg/kg twice weekly), both treatments at the same regimens, or vehicle. Arthritis score and paw thickness were recorded twice weekly. The rats were sacrificed on D28 and hind paws were removed for radiographic, histological and immunohistochemical analysis. The effects of treatments on osteoclastogenesis were determined by Tartrate resistant acid phosphatase (TRAP) staining. Micro-CT of the tibia was carried out for histomorphometric analysis. Bone mass density was evaluated by densitometry. Results MTX significantly decreased the severity of CIA, whereas ZA slightly exacerbated it. When these two drugs were used in combination, MTX prevented the pro-inflammatory effect of ZA. The combination of ZA with MTX was more effective than MTX alone for reducing structural joint damage with a dramatic decrease of osteoclasts' number in the eroded joints. However, MTX alone also significantly reduced the number of osteoclasts and the number of CD68+ mononuclear cells. ZA alone, or ZA with MTX, significantly increased the systemic bone mass density measured by densitometry and bone volume on histomorphometric analysis. Conclusions A combination of MTX and ZA prevented both bone erosion and systemic bone loss in a rat model of arthritis. Both treatments independently decreased the number of osteoclasts in the eroded joint. However, while MTX probably acts mainly through a decrease of inflammation, ZA has a direct effect on osteoclasts, allowing a dramatic down-regulation of these cells in inflamed joints. These two different mechanisms of action provide support for the use of a combination of these two drugs to improve the prevention of structural joint damage in RA

Cardiovascular effects of arginase inhibition in spontaneously hypertensive rats with fully developed hypertension

Aims Growing evidence suggests that arginase misregulation plays a key role in the pathophysiology of essential hypertension. In the present study, we investigated the potential cardiovascular therapeutic effects of a long-term treatment with an arginase inhibitor in adult spontaneously hypertensive rats (SHR) with fully developed hypertension. Methods and results Treatment of 25-week-old SHR with the arginase inhibitor Nω-hydroxy-nor-l-arginine (nor-NOHA, 40 mg/day for 10 weeks) sustainably reduced systolic blood pressure (−30 mmHg, P < 0.05). The antihypertensive effect of nor-NOHA was associated with changes on mesenteric artery reactivity including the restoration of angiotensin-II-induced contraction and acetylcholine-induced vasodilation to the values of normotensive Wistar Kyoto rats. Both nitric oxide synthase and cyclooxygenase-dependent mechanisms account for the improvement of endothelial function afforded by the arginase inhibitor, which in addition blunted hypertension-induced endothelial arginase I overexpression in mesenteric arteries. Nor-NOHA also prevented the remodelling of aorta as measured by collagen content and media/lumen ratio, and improved the compliance of carotid artery in SHR. Cardiac fibrosis assessed by collagen content of left heart ventricle was reduced by nor-NOHA, with no significant effect on cardiac hypertrophy. Conclusion Our results report that a long-term treatment with an arginase inhibitor reduced blood pressure, improved vascular function, and reduced cardiac fibrosis in SHR with fully developed hypertension. These data suggest that arginase represents a promising novel target for pharmacological intervention in essential hypertensio

Cystic angiomatosis, a heterogeneous condition: four new cases and a literature review

Background: Cystic angiomatosis (CA) is a rare disorder causing bony cysts. It displays some similarity to Gorham–Stout disease (GSD), but has a much better local prognosis, despite the larger number of cysts. These 2 conditions also differ in terms of their location, visceral involvement, and response to treatment. Methods: We report 4 cases of CA, including 1 sclerosing form, which we compare with cases from a literature review performed with PRISMA methodology. Results: We reviewed 38 articles describing 44 other patients. Mean age at diagnosis for the 48 patients (our 4 patients + the 44 from the review) was 22.5 years, and 28 of the patients were men. The femur was involved in 81% (n = 39), the pelvis in 73% (n = 35), the humerus in 52% (n = 25), the skull in 48% (n = 23), and the vertebrae in 44% (n = 21). Visceral lymphangiomatosis (either clinical, or detected on autopsy) was also reported in 35% (n = 18) of the patients. The spleen was the most frequently involved organ (n = 12), followed by the lungs and pleura (n = 8). Liver cysts and/or chylothorax were rarely reported (5 cases), but were invariably fatal. Radiation therapy on bone or soft tissue masses was ineffective, as was interferon alpha, in the 2 patients in which this drug was tested. The efficacy of bisphosphonate was at best equivocal. Conclusion: The progression of CA is unpredictable and treatments effective against GSD, such as bisphosphonates and radiotherapy, have proved ineffective for this condition. New treatments are thus urgently required

Redocumentariser la Tapisserie de Bayeux : base de données documentaire et système d’informations spatialisées

Dans le cadre du projet de refonte du Musée de la Tapisserie de Bayeux à l’horizon 2024, mené par la Ville de Bayeux et la DRAC Normandie, en collaboration avec la région Normandie et le département Calvados, des outils numériques permettant de découvrir et d’étudier la Tapisserie sous un angle nouveau ont été élaborés.Ces outils consistent en un « Système d’information documentaire spatialisée » (SIDS), combinaison d’un système documentaire et d’un système d’information spatialisé. Ils offrent des solutions de gestion et de valorisation des ressources documentaires relatives à la Tapisserie de Bayeux, et doivent à terme accompagner l’ensemble des publics qui s’intéressent à l’œuvre, notamment les chercheurs en sciences humaines, les conservateurs-restaurateurs, les spécialistes du textile, le grand public. Ce projet est le fruit d’un étroit partenariat entre l’État, la Ville de Bayeux, l’université de Caen Normandie, le CNRS et l’Ensicaen.Alongside the renewal of the Bayeux Tapestry Museum planned for 2024, led by the city of Bayeux, the DRAC Normandy, the Normandy region and the Calvados department, several numeric tools have been created to discover and examine the Tapestry in new ways.Those tools consist in a Spatialised Document Information System (SDIS), combining a Document database and a Spatialised information system. They offer solutions to manage and to enhance documentary resources related to the Bayeux Tapestry and should, at the end, accompany all the persons interested in the Tapestry, particularly scholars in Humanities, curators-restorers, specialists in textile and the public. This project is the result of a close collaboration between the State, the city of Bayeux, the University of Caen Normandy, the CNRS and the Ensicaen.Nell’ambito del progetto di ristrutturazione del Museo dell’Arazzo di Bayeux che dovrebbe concludersi nel 2024, portato avanti dalla Città di Bayeux e dalla DRAC Normandie, in collaborazione con la regione Normandia e il dipartimento del Calvados, sono stati elaborati nuovi strumenti informatici che permettono di scoprire e studiare l’Arazzo da un nuovo punto di vista.Questi strumenti consistono in un « Sistema d’informazione documentaria spazializzata » (SIDS), combinazione di un sistema documentario e di un sistema d’informazione spazializzato. Essi offrono delle soluzioni di gestione e di valorizzazione delle fonti documentarie relative all’Arazzo di Bayeux, e devono accompagnare i vari fruitori dell’opera, soprattutto i ricercatori in scienze umane, i conservatori-restauratori, gli specialisti del tessile, il grande pubblico. Questo progetto è il frutto di uno stretto partenariato tra lo Stato, la Città di Bayeux, l’Università di Caen Normandie, il CNRS e l’ENSICAEN

Cardiovascular effects of arginase inhibition in spontaneously hypertensive rats with fully developed hypertension

Growing evidence suggests that arginase misregulation plays a key role in the pathophysiology of essential hypertension. In the present study, we investigated the potential cardiovascular therapeutic effects of a long-term treatment with an arginase inhibitor in adult spontaneously hypertensive rats (SHR) with fully developed hypertension