Search results for "shock wave"

Clinical comparison of extracorporeal piezoelectric lithotripsy (EPL) and intracorporeal electrohydraulic lithotripsy (EHL) in difficult bile duct st…

1995

Today, nearly 90% of common bile duct stones are extracted endoscopically. Problems are encountered if there are large stones or a duct stenosis. Extracorporeal piezoelectric lithotripsy (EPL) as well as intracorporeal electrohydraulic lithotripsy (EHL) serve as an alternative to surgical intervention for those few patients in whom endoscopic measures have failed. A total of 35 patients with common bile duct stones in whom conventional endoscopic treatment had failed were selected on the condition that stone visualization through ultrasound was possible and that the papilla was within easy reach of the endoscope. Patients fulfilling the inclusion criteria were randomly treated either by EPL…

Successful treatment of gallstone ileus (Bouveret's syndrome) by using extracorporal shock wave lithotripsy and argon plasma coagulation.

2006

ANALGESIC EFFECT OF EXTRACORPOREAL SHOCK-WAVE THERAPY ON CHRONIC TENNIS ELBOW

1996

We report a controlled, prospective study to investigate the effect of treatment by low-energy extracorporeal shock waves on pain in tennis elbow. We assigned at random 100 patients who had had symptoms for more than 12 months to two groups to receive low-energy shock-wave therapy. Group I received a total of 3000 impulses of 0.08 mJ/mm2 and group II, the control group, 30 impulses. The patients were reviewed after 3, 6 and 24 weeks. There was significant alleviation of pain and improvement of function after treatment in group I in which there was a good or excellent outcome in 48% and an acceptable result in 42% at the final review, compared with 6% and 24%, respectively, in group II.

Radiative accretion shocks along nonuniform stellar magnetic fields in classical T Tauri stars

2013

(abridged) AIMS. We investigate the dynamics and stability of post-shock plasma streaming along nonuniform stellar magnetic fields at the impact region of accretion columns. We study how the magnetic field configuration and strength determine the structure, geometry, and location of the shock-heated plasma. METHODS. We model the impact of an accretion stream onto the chromosphere of a CTTS by 2D axisymmetric magnetohydrodynamic simulations. Our model takes into account the gravity, the radiative cooling, and the magnetic-field-oriented thermal conduction. RESULTS. The structure, stability, and location of the shocked plasma strongly depend on the configuration and strength of the magnetic f…

YSO accretion shocks: magnetic, chromospheric or stochastic flow effects can suppress fluctuations of X-ray emission

2013

Context. Theoretical arguments and numerical simulations of radiative shocks produced by the impact of the accreting gas onto young stars predict quasi-periodic oscillations in the emitted radiation. However, observational data do not show evidence of such periodicity. Aims. We investigate whether physically plausible perturbations in the accretion column or in the chromosphere could disrupt the shock structure influencing the observability of the oscillatory behavior. Methods. We performed local 2D magneto-hydrodynamical simulations of an accretion shock impacting a chromosphere, taking optically thin radiation losses and thermal conduction into account. We investigated the effects of seve…

Multiple accelerated particle populations in the Cygnus Loop with Fermi-LAT

2021

The Cygnus Loop (G74.0-8.5) is a very well-known nearby supernova remnant (SNR) in our Galaxy. Thanks to its large size, brightness, and angular offset from the Galactic plane, it has been studied in detail from radio to $\gamma$-ray emission. The $\gamma$ -rays probe the populations of energetic particles and their acceleration mechanisms at low shock speeds. We present an analysis of the $\gamma$-ray emission detected by the Large Area Telescope on board the Fermi Gamma-ray Space Telescope over 11 years in the region of the Cygnus Loop. We performed detailed morphological and spectral studies of the $\gamma$-ray emission toward the remnant from 100 MeV to 100 GeV and compared it with X-ra…

Transient solutions for temperature and pressure waves in fluid-saturated porous rocks

1996

SUMMARY In this paper, hot-fluid migration dynamics for a fluid-saturated porous rock is analysed theoretically. We first recall a Bonafede model implemented with a classical scale analysis; this allows us to discuss a fully non-linear formulation related to transient phenomena, which is solved analytically as a solitary shock wave. The resulting time-scales are particularly small, corresponding to intense short-time geothermal phenomena. A novel non-linear migration mechanism, related to Darcy convection, is also discussed.

On critical behaviour in generalized Kadomtsev-Petviashvili equations

2016

International audience; An asymptotic description of the formation of dispersive shock waves in solutions to the generalized Kadomtsev–Petviashvili (KP) equation is conjectured. The asymptotic description based on a multiscales expansion is given in terms of a special solution to an ordinary differential equation of the Painlevé I hierarchy. Several examples are discussed numerically to provide strong evidence for the validity of the conjecture. The numerical study of the long time behaviour of these examples indicates persistence of dispersive shock waves in solutions to the (subcritical) KP equations, while in the supercritical KP equations a blow-up occurs after the formation of the disp…

“Extracorporeal shock wave therapy for lateral epicondylitis—a double blind randomized controlled trial” by C. A. Speed et al., J Orthop Res 2002;20:…

2003

Comparative analysis of direct and indirect costs of two minimally invasive techniques for the treatment of renal/ureteral calculi smaller than 2 cm

2020

[EN] Objective: To perform a comparative analysis of indirect and direct costs of two minimally invasive techniques (extracorporeal shock wave lithotripsy (ESWL) vs. ureteroscopy with holmium laser (URS/RIRS)) for the treatment of renal/ureteral calculi smaller than 2 cm. Material and methods: Prospective, comparative, non-randomized study of 84 patients treated for kidney stones smaller than 2 cm between January and December 2016. Of these, 38 (45.67%) were treated with ESWL (18 renal lithiasis and 20 ureteral lithiasis) and 46 (54.32%) with URS/RIRS (22 renal lithiasis and 24 ureteral lithiasis). A total of 19 (41.3%) patients in the URS/RIRS group and 15 (39.5%) patients in the ESWL grou…