Search results for "Bubble"
showing 10 items of 167 documents
Conic optical fiber probe for generation and characterization of microbubbles in liquids
2021
Abstract A novel optical fiber probe has been developed to provide mechanical stability to microbubbles generated in fluids, the tip of the fiber is etched with hydrofluoric acid to pierce a truncated horn that fastens the microbubbles to the fiber tip and prevents misalignment or detachment caused by convection currents, vibrations or shocks in the liquid. Microbubbles are photo-thermally generated on the etched fiber and used as Fabry-Perot cavity sensor. Two methods were used to interrogate the probe: the first one, in the wavelength domain, is suitable for calibration in static or quasi static situations; the second one, in the time domain, can be used in dynamic environments. Experimen…
Deformation of bubbles in silicon gel insulation under an alternating electric field
2019
The behavior of silicone gel under electrical stress plays a significant role in the reliability and durability of high voltage electronic power devices due to its widespread use for the insulation of IGBT modules and other components. The charges accumulation at the bubble boundaries leads to significant displacements due to the establishment of Coulombic forces and the high deformability of colloidal system. The main purpose of this work is to validate a numerical approach useful to investigate, for a given silicone gel, the non-linear relation between the applied HVDC stress and the electric field over an air bubble within the insulation bulk. The analysis has been carried out by means o…
The roles of microlites and phenocrysts during degassing of silicic magma
2022
Abstract Silicic magmas span a wide range of eruptive styles between explosive and effusive, and transitions between these styles are commonplace. Yet the triggers of switches in eruptive style remain poorly understood. Eruptions are mostly driven by degassing of magmatic water and their eruption style - effusive or explosive - is likely governed by the efficiency of outgassing as well as magma ascent rate. Microlites and phenocrysts are often purported to promote heterogeneous bubble nucleation and outgassing, both key variables in the degassing dynamics that become crucial in controlling the eruptive style. Here, in order to shed light on the role of nature, size and abundance of crystals…
Targeting distinct myeloid cell populations in vivo using polymers, liposomes and microbubbles
2016
Identifying intended or accidental cellular targets for drug delivery systems is highly relevant for evaluating therapeutic and toxic effects. However, limited knowledge exists on the distribution of nano- and micrometer-sized carrier systems at the cellular level in different organs. We hypothesized that clinically relevant carrier materials, differing in composition and size, are able to target distinct myeloid cell subsets that control inflammatory processes, such as macrophages, neutrophils, monocytes and dendritic cells. Therefore, we analyzed the biodistribution and in vivo cellular uptake of intravenously injected poly(N-(2-hydroxypropyl) methacrylamide) polymers, PEGylated liposomes…
Parametrical Optomechanical Oscillations in PhoXonic Whispering Gallery Mode Resonators
2019
AbstractWe report on the experimental and theoretical analysis of parametrical optomechanical oscillations in hollow spherical phoxonic whispering gallery mode resonators due to radiation pressure. The optically excited acoustic eigenmodes of the phoxonic cavity oscillate regeneratively leading to parametric oscillation instabilities.
Air bubble location inside the uterus after transfer: is the embryo really there?
2007
Objective To demonstrate that the location of the air bubble after embryo transfer (ET) does not necessarily indicate the final embryo location. Design Case report. Setting Private clinic. Patient(s) A couple with primary infertility for whom a diagnosis of bicornuate uterus with a very open angle between horns was confirmed. Intervention(s) Laparoscopy and hysteroscopy were performed before an IVF cycle in which a single embryo was replaced. Main Outcome Measure(s) Air bubble image immediately after ET and gestational sac location 3 weeks later. Result(s) Immediately after a single ET, the air bubble was seen in the left uterine horn. Three weeks later, a gestational sac was seen in the ri…
The added diagnostic value of 64-row multidetector CT combined with contrast-enhanced US in the evaluation of hepatocellular nodule vascularity: impl…
2009
The aim of this study was to assess the added diagnostic value of contrast-enhanced US (CEUS) combined with 64-row multidetector CT (CT) in the assessment of hepatocellular nodule vascularity in patients with liver cirrhosis. One hundred and six cirrhotic patients (68 male, 38 female; mean age +/- SD, 70 +/- 7 years) with 121 biopsy-proven hepatocellular nodules (72 hepatocellular carcinomas, 10 dysplastic and 15 regenerative nodules, 12 hemangiomas, and 12 other benignancies) detected during US surveillance were prospectively recruited. Each nodule was scanned by CEUS during the arterial (10-40 s), portal venous (45-90 s), and delayed sinusoidal phase (from 100 s after microbubble injectio…
Analysis of different contrast enhancement patterns after microbubble-based contrast agent injection in liver hemangiomas with atypical appearance on…
2006
BACKGROUND: We describe different possible enhancement patterns in liver hemangiomas with atypical appearance on baseline ultrasound after microbubble-based contrast agent injection. METHODS: From a series of 253 consecutive lesions that were indeterminate on baseline ultrasound and then scanned after injection of air-filled microbubble contrast agent, 65 focal liver lesions were retrospectively selected on the basis of a diagnosis of liver hemangioma on multiphase contrast-enhanced computed tomography (n = 23), magnetic resonance imaging (n = 27), or histology (n = 15). Each lesion was scanned during arterial phase (30 s after microbubble injection) and late phase (5 min after injection). …
Contrast-enhanced transcranial Doppler ultrasonography in the diagnosis of brain death
2013
The diagnosis of brain death (BD) is based on clinical criteria including deep coma, brain stem areflexia and apnoea. Depending on different local guidelines, confirmatory technical tests are sometimes mandatory.1 Since the 1990s, transcranial Doppler sonography (TCD) has found its place in these circumstances and fulfils most of the criteria of an ‘ideal test’ in confirming BD. To confirm intracranial circulatory arrest (CA) with Doppler sonography, typical flow patterns must be recorded in bilateral intracranial and extracranial brain-supplying arteries.2 A completely absent intracranial flow signal is not a reliable sign to determine CA because this can be due to transmission problems. I…
Analysis of Internal Jugular Vein Insufficiency—A Comparison of Two Ultrasound Methods
2006
Abstract Jugular venous valve insufficiency is a contributing factor to different pathologic conditions. For assessment of insufficiency, two ultrasound techniques have been developed, that are based on very different methodology (direct Doppler assessment versus air contrast ultrasound venography [ACUV]). This study was conducted to compare these two methods to improve comparability of existing studies and diagnostic accuracy in future studies. The function of 40 valves was determined in 20 individuals during a Valsalva maneuver. For direct Doppler assessment, valvular competence was assessed on basis of Doppler recordings, following recently established criteria. Valvular insufficiency in…