Search Results (9)

Spasticity is a common complication in patients with neurological disorders, increasing disability and hampering quality of life. Combined treatment with focused shock waves (fESWT) and botulinum toxin (BoNT-A) has been shown to increase the effectiveness and duration of the effect of BoNT-A on spasticity in patients with brain injuries. We studied the effectiveness of the combination of unfocused shock waves (uESWT) and BoNT-A on spasticity. This prospective study with systematic randomization included 24 patients with brain injury, a small sample size due to clinical limitations, and spasticity was measured using the Ashworth scale (AS) for those with lower limb involvement; gait speed was assessed using the 10-m gait test (10MWT). To judge patient satisfaction with treatment, we used the Consumer Reports Effectiveness Scale-4 (CRES-4). Both uESWT and fESWT with BoNT-A resulted in a 3-point improvement in the median spasticity score, which was maintained from week 2 to week 26, and a statistically significant reduction in the 10MWT was observed. Furthermore, the proportion of patients who were very satisfied with the treatment was higher with uESWT (91%) than with fESWT (69.2%). To the authors’ knowledge, this is the first study to evaluate the added benefit of concurrent and combined treatment with uESWT and BoNT-A injections to improve spasticity in patients with stroke or multiple sclerosis and show higher patient satisfaction with the treatment. Full article

In mineral metallurgy, the flashing unit is key to returning the slurry to atmospheric conditions. Its primary function is to achieve pressure letdown, and during the process, shock waves are generated to maximize energy dissipation. Investigating the location and expansion of shock waves is the focal point of this study due to their importance in flashing unit design. A CFD model coupled with a homogeneous relaxation model (HRM) was used to simulate the flashing process of mineral slurry. The flow behavior, including velocity, pressure, and the shape and location of the shock waves, were obtained using simulation under different unit design and operating parameters. These results would provide valuable insights into the design of flashing units and guidance for the safe operation and maintenance of devices. Full article

Lateral elbow tendinopathy (LET) is characterized by pain, poor muscle strength of the wrist ex-tensors, and disability. Among the conservative rehabilitative approaches, focal as well as radial extracorporeal shock wave therapy (ESWT), are considered effective in LET management. The objective of this study was to compare the safety and effectiveness of focal (fESWT) and radial (rESWT) in terms of LET symptoms and the strength of wrist extensors, taking into account potential gender differences. This is a retrospective longitudinal cohort study of patients with LET treated with ESWT that had received a clinical and functional evaluation, including visuo-analogic scale (VAS), muscle strength using an electronic dynamometer during Cozen’s test, and the patient-rated tennis elbow evaluation (PRTEE) questionnaire. Follow-ups were carried out weekly in four visits after enrollment, and at 8 and 12 weeks. During the follow-ups, the VAS score decreased in both treatments, even if patients receiving fESWT reported early pain relief compared to those treated with rESWT (time for treatment p-value < 0.001). Additionally, peak muscle strength increased independently of the device used, and again more rapidly in the fESWT group (time for treatment p-value < 0.001). In the stratified analysis for sex and for the type of ESWT, rESWT appears to be less effective in female participants in terms of mean muscle strength and PRTEE scores, without differences according to the type of device used. The rESWT group reported a higher rate of minor adverse events (i.e., discomfort, p = 0.03) compared to fESWT. Our data suggest that both fESWT and rESWT might be effective in improving LET symptoms, even if the higher rate of painful procedures were reported in patients treated with rESWT. Full article

Carbon nanotube–polymethyl siloxane (CNT-PDMS) composite transducers generate shock waves using optoacoustic technology. A thin layer of thermally conductive CNT and elastomeric polymer, PDMS, is applied on the concave surface of transparent polymethylmethacrylate (PMMA) to convert laser energy to acoustic energy using the thermoelastic effect of the composite transducer. The efficient conversion of laser energy requires an optimum utilization of the different properties of composite transducers. Among these properties, the diameter of composite transducers is a significant parameter. To practically verify and understand the effect of the diameter of composite transducers on the properties of shock waves, CNT-PDMS composite transducers with different diameters and focal lengths were constructed. Increases in the diameter of the composite transducer and input laser energy resulted in increased peak pressures of the shock waves. The maximum positive and negative pressures of the shock waves generated were 53 MPa and −25 MPa, respectively. This practically demonstrates that high peak amplitudes of shock waves can be achieved using larger transducers, which are suitable for practical applications in transcranial studies. Full article

In vitro investigations, which comprise the bulk of research efforts geared at identifying an underlying biomechanical mechanism for extracorporeal shock wave therapy (ESWT), are commonly hampered by inadequate descriptions of the underlying therapeutic acoustical pressure waves. We demonstrate the necessity of in-situ sound pressure measurements inside the treated samples considering the significant differences associated with available applicator technologies and cell containment. A statistical analysis of pulse-to-pulse variability in an electrohydraulic applicator yields a recommendation for a minimal pulse number of n = 300 for cell pallets and suspensions to achieve reproducible treatments. Non-linear absorption behavior of sample holders and boundary effects are shown for transient peak pressures and applied energies and may serve as a guide when in-situ measurements are not available or can be used as a controllable experimental design factor. For the use in microbiological investigations of ESWT we provide actionable identification of common problems in describing physical shockwave parameters and improving experimental setups by; (1) promoting in-situ sound field measurements, (2) statistical evaluation of applicator variability, and (3) extrapolation of treatment parameters based on focal and treatment volumes. Full article

Medial collateral ligament (MCL) injuries are the most frequent ligamentous injuries of the knee. Focused extracorporeal shock wave therapy (f-ESWT) is progressively expanding its field of application to many musculoskeletal pathologies. Although there is evidence surrounding the efficacy of f-ESWT in tendinopathies, no studies have described the usefulness of ultrasound (US)-guided f-ESWT in the treatment of ligament injuries. Herein, we report a case of a MCL injury treated with f-ESWT. Moreover, our case shows the importance of using ultrasonography in determining the effect of treatment. A 60-year-old man with a focal area of lesion in the deep fibers underwent 4 weekly sessions of US-guided f-ESWT to the injured ligament area. His pain decreased to a visual analog scale (VAS) of 3 at the end of the treatment and was completely resolved at the 1-month follow-up visit, with these results being maintained at 4-month follow-up. The US examination showed an initial deposition of “newly formed tissue” at the site of previous injury of the proximal MCL insertion, and a reduction in MCL thickness together with an improvement in echostructure. Based on this result, we speculate that non-surgical ligament injuries could be a new indication for f-ESWT. However, further investigation on the effects of f-ESWT for ligament injuries is needed. Full article

In traditional laser-induced breakdown spectroscopy (LIBS) applications, the line intensity and analysis capability are susceptible to plasma shielding. To investigate the shielding effects on the characteristics of Cu plasma in air, a ~120-picosecond laser with a wavelength of 1064 nm was employed to produce plasma. The plasma temperature and electron density were calculated under the condition of local thermal equilibrium (LTE) and optically thin, while the relationships between the line intensity, plasma temperature and electron density were analyzed. Moreover, the LTE condition was validated by the McWhirter relation, plasma relaxation time and diffusion length, and the optically thin condition was observed through the variation in line intensity. The results indicated that when the focal point was below the target surface, the plasma shielding was the weakest, and the highest line intensity could be obtained. In addition, there was a positive correlation between the increased plasma temperature and the degree of shielding effect. When the focal point was above the target surface, the high-irradiance pulse directly broke down the free air and produced a shock wave. Under the high pressure of the over-heated shock wave, the line intensity, plasma temperature and electron density increased again. This study provides an important insight into the experiments and applications of picosecond LIBS. Full article

The Mw7.9 Alaska earthquake at 09:31:40 UTC on 23 January 2018 occurred as the result of strike slip faulting within the shallow lithosphere of the Pacific plate. Global positioning system (GPS) data were used to calculate the slant total electron contents above the epicenter. The singular spectrum analysis (SSA) method was used to extract detailed ionospheric disturbance information, and to monitor the co-seismic ionospheric disturbances (CIDs) of the Alaska earthquake. The results show that the near-field CIDs were detected 8–12 min after the main shock, and the typical compression-rarefaction wave (N-shaped wave) appeared. The ionospheric disturbances propagate to the southwest at a horizontal velocity of 2.61 km/s within 500 km from the epicenter. The maximum amplitude of CIDs appears about 0.16 TECU (1TECU = 10¹⁶ el m⁻²) near the epicenter, and gradually decreases with the location of sub-ionospheric points (SIPs) far away from the epicenter. The attenuation rate of amplitude slows down as the distance between the SIPs and the epicenter increases. The direction of the CIDs caused by strike-slip faults may be affected by the horizontal direction of fault slip. The propagation characteristics of the ionospheric disturbance in the Alaska earthquake may be related to the complex conditions of focal mechanisms and fault location. Full article

In the present study, a two-dimensional axisymmetry unsteady numerical simulation that implements high-frequency laser energy deposition was performed to understand its influence on drag reduction in supersonic flow. The energy deposition was modeled as the increase of the temperature inside the focal region. The drag reduction characteristics were investigated by changing the frequency of the deposition, the distance between the focus of the deposition and the body, and the power of the laser. The results showed that drag could be reduced by 60% when there was a single energy deposition. As the operating frequency increased, up to 70% drag reduction was obtained. When the laser energy was deposed more frequently than 75 kHz, the normalized drag converged regardless of the deposition scenario, which resulted from the multiple interactions between the blast wave and the reflected shock. A similar tendency was found from the results of various focal distances. According to the results of this study on the effect of the deposition energy, it is expected to achieve the same effect as with low energy by increasing the frequency of the deposition. Full article