Wyniki wyszukiwania - Biblioteka Nauki

1

Recent development in all-optical ultrasonic shear wave inspection

100%

Messaoudi M. , Pouet B.

Badania Nieniszczące i Diagnostyka

|

2018

|

tom nr 3

31--34

EN

A laser-based technique for efficiently generating and detection ultrasonic shear-wave is described. For the detection, a new laser interferometric scheme was recently developed in order to measure the three components of the ultrasonic field. This scheme takes advantage of the large étendue achieved with interferometer based on two-wave mixing in photorefractive crystal. Detection of the out-of-plane component as well as the two orthogonal in-plane components of the surface displacement is achieved using a single laser probe beam and a single, large aperture, collecting optic combined with detector arrays. With this interferometer, all wave types can be detected. The detection of the in-plane component allows efficient detection of shear waves, particularly when the direction of ultrasounds propagation is normal to the surface of inspection. However, for remote shear wave inspection, one must also be able to efficiently generate normal incidence shear waves. With laser-based generation, shear waves are mainly generated off the normal incidence. In this paper, in addition to presenting the tri-component interferometer, an improved method for normal-incidence shear wave generation is described. The combination of shear-wave LU generation with a multi-component laser receiver makes LU pulse-echo shear-wave inspection possible. Results from characterization of the receiver and of the generation are shown.

PL

Opisano technikę laserową do wydajnego generowania i wykrywania ultradźwiękowych fal poprzecznych. W celu detekcji opracowano nowy laserowy układ interferometryczny do pomiaru trzech składników pola ultradźwiękowego. Schemat ten wykorzystuje dużą wartość uzyskaną przy pomocy interferometru opartego na mieszaniu dwóch fal w fotorefrakcyjnym krysztale. Wykrywanie elementu poza płaszczyzną, jak również dwóch ortogonalnych elementów w płaszczyźnie przemieszczenia powierzchni, uzyskuje się za pomocą pojedynczej wiązki sondy laserowej i pojedynczej, dużej apertury, zbierającej układ optyczny połączonej z układami detektorów. Za pomocą tego interferometru można wykryć wszystkie typy fal. Wykrywanie elementu w płaszczyźnie umożliwia skuteczne wykrywanie fal poprzecznych, szczególnie gdy kierunek propagacji ultradźwięków jest normalny do powierzchni kontroli. Jednak w przypadku zdalnej inspekcji fali poprzecznej ważne jest również by móc wydajnie generować padające fale poprzeczne. W przypadku generowania laserowego fale poprzeczne są wzbudzane głównie poza normalną . W niniejszej pracy, oprócz prezentacji interferometru trójskładnikowego, opisano ulepszoną metodę generowania padających fal normalnych. Połączenie generatora LU fali padającej z wieloskładnikowym odbiornikiem laserowym umożliwia inspekcję falą poprzeczną z wykorzystaniem trybu LU pulse-echo. Przedstawiono wyniki charakteryzacji odbiornika i generatora.

2

Human opiorphin is a naturally occurring antidepressant acting selectively on enkephalin-dependent delta-opioid pathways

80%

Javelot H. , Messaoudi M. , Garnier S. , Rougeot C.

Journal of Physiology and Pharmacology

|

2010

|

tom 61

|

nr 3

355-362

EN

Human opiorphin protects enkephalins from degradation by human neutral endopeptidase and aminopeptidase-N and inhibits pain perception in various behavioral rodent models of pain via endogenous enkephalin-related activation of opioidergic pathways. In addition to pain control, endogenous opioid pathways are also implicated in the modulation of emotion-related behaviors. Thus, we explored the dose-dependent motivational responses induced by opiorphin using the forced swim test, the standard rat model of depression. In addition, to further understand the endogenous events triggered by opiorphin, we investigated the specific involvement of µ- or -opioid receptor-dependent pathways. In parallel, the locomotor activity test was used to detect possible sedation or hyperactivity. Here, we report for the first time that at 1-2 mg/kg i.v. doses, opiorphin elicited antidepressant-like effects by activating endogenous -opioidergic pathways, since that activation was reversed by the selective -opioid antagonist naldrindole (10 mg/kg i.p.). The antidepressive behavioral responses exerted by opiorphin are specific at systemically active doses. Treated-rats did not develop either hypo- or hyper-active responses in a locomotor test or amnesic behavioral response in the passive avoidance rat model. In addition, opiorphin did not induce either anxiolytic-, or anxiogenic-like responses in the conditioned defensive burying test. Taking the data together, we conclude that opiorphin is able to elicit antidepressant-like effects, mediated via -opioid receptor-dependent pathways, by modulating the concentrations of endogenous enkephalin released in response to specific physical and/or psychological stimuli. Thus, opiorphin or optimized derivatives is a promising single candidate to treat disorders that include both pain and mood disorders, particularly depression.

3

Systemically active human opiorphin is a potent yet non-addictive analgesic without drug tolerance effects

70%

Rougeot C. , Robert F. , Menz L. , Bisson J.-F. , Messaoudi M.

Journal of Physiology and Pharmacology

|

2010

|

tom 61

|

nr 4

483-490

EN

Human opiorphin QRFSR-peptide protects enkephalins from degradation by human neutral endopeptidase (hNEP) and aminopeptidase-N (hAP-N) and inhibits pain perception in a behavioral model of mechanical acute pain (1). Here, using two other pain rat models, the tail-flick and the formalin tests, we assess the potency and duration of the antinociceptive action of opiorphin with reference to morphine. The occurrence of adverse effects with emphasis on the side-effect profile at equi-analgesic doses was compared. We demonstrate that opiorphin elicits minimal adverse morphine-associated effects, at doses (1-2 mg/kg, i.v.) that produce a comparable analgesic potency in both spinally controlled thermal-induced acute and peripheral chemical-induced tonic nociception. The analgesic response induced by opiorphin in the formalin-induced pain model preferentially requires activation of endogenous µ-opioid pathways. However, in contrast to exogenous µ-opioid agonists such as morphine, opiorphin, does not develop significant abuse liability or antinociceptive drug tolerance after subchronic treatment. In addition, anti-peristaltism was not observed. We conclude that opiorphin, by inhibiting the destruction of endogenous enkephalins, which are released according to the painful stimulus, activates restricted opioid pathways specifically involved in pain control, thus contributing to a greater balance between analgesia and side-effects than found with morphine. Therefore, opiorphin could give rise to new analgesics endowed with potencies similar to morphine but with fewer adverse effects than opioid agonists. Its chemical optimization, to generate functional derivatives endowed with better bioavailability properties than the native peptide, could lead to a potent class of physiological type analgesics.