RESUMEN
Acoustic Doppler current profilers (ADCPs) were developed to acquire water current velocities, as well as depth-dependent echo intensities. As the backscattering strength of an underwater object can be estimated from the measured echo intensity, the ADCP can be used to estimate plankton populations and distributions. In this study, the backscattering strength of bubble clusters in a water tank was estimated using the commercial ADCP as a proof-of-concept. Specifically, the temporal variations in the backscattering strength and the duration of bubble existence were quantitatively evaluated. Additionally, the PDSL (population density spectrum level) and VF (void fraction) of the artificial bubbles were characterized based on the obtained distribution characteristics using a PDPA (phase Doppler particle analyzer).
Asunto(s)
Acústica , AguaRESUMEN
On rare occasions, percutaneous vertebroplasty (PV) may be associated with adverse spinal and extraspinal events. Subarachnoid hemorrhage (SAH) has not been reported complication following a PV. This is a report of two elderly women with spine compressions who developed idiopathic SAH after injecting polymethylmethacrylate into the thoracolumbar region transcutaneously. PV was performed as an usual manner on prone position under local anesthesia for these patients. During the interventions, two patients complained of a bursting nature of headache and their arterial blood pressure was jumped up. Computed tomography scans revealed symmetric SAH on the both hemispheres and moderate degree of hydrocephalus. Any intracranial vascular abnormalities for their SAH were not evident on modern neuroangiography modalities. One patient received a ventricular shunt surgery, but both fully recovered from the procedure-related SAH. The pathophysiologic mechanism that induce SAH will be discussed, with suggesting the manner that prevent and minimize this rare intracranial complication after PV.
