Microbubbles have been presumed as gaseous emboli, which originate during mechanical heart valve closure, but are not seen in bioprosthetic valves. In this report, we presented a cluster of Microbubbles mimicking mobile thrombus in a patient with mechanical mitral valve prosthesis. A 30-year-old female with a history of implanted mechanical valve at the mitral position underwent a routine examination. She was asymptomatic and her physical examination was unremarkable. Transthoracic echocardiography showed a mobile thrombus-like mass on the ventricular side of the prosthetic mitral valve moving into the left ventricular outflow tract. However, close examination of images indicated that the mass was in fact intense Microbubbles mimicking thrombus. Intense mobile Microbubbles can be misdiagnosed as a mobile thrombus. We recommend and underscore the importance of detailed echocardiographic examination in case of mobile mass to avoid misdiagnosis in patients with mechanical heart valves.

In the present work, the dynamics of a single spherical gas bubble surrounded by a rheopectic fluid obeying the Quemada model is numerically investigated while the bubble undergoes oscillatory motion due to acoustic forcing. The generalized form of the Rayleigh–Plesset equation has been used for studying bubble dynamics in Quemada fluids. The integro-differential equation representing the dynamics of the bubble is solved numerically using the finite-element method (FEM) and also the Gauss–Laguerre quadrature (GLQ) method. The effect of rheopexy number (Rx) and viscosity ratio (ξ) are then investigated over a wide range of working parameters. Numerical results show that the rheopectic behavior of the fluid surrounding the bubble can dramatically affect the bubble dynamics. It is predicted that for highly anti-thixotropic fluids, harmonics are affected so much so that the bubble may exhibit chaotic behavior. For instance, at Rx = 0. 001 and ξ = 1/81, a one-micron-sized bubble may attain a size almost 30 times of its initial size. The general conclusion is that, in sonography, Microbubbles dispersed in rheopectic fluids may indeed be considered as a potent ultrasound contrast agent provided that the fluid is just moderately anti-thixotropic otherwise its chaotic response might damage the adjacent tissues.

Venturi bubble generators have been extensively studied because of having a simple structure and high foaming efficiency, while producing a uniform bubble size. The effect of a noncondensable gas on hydraulic cavitation was considered to improve the Zwart-Gerber-Belamri cavitation model. This improved model and a population balance model were used to study the effect of cavitation on bubble fragmentation. The CFD-PBM results were compared with experimental results, and the accuracy of the improved calculation method was verified in terms of the distributions for the cavitation cavity, gas phase, and bubble size. The calculation results showed that increasing the noncondensable gas content over a certain range promoted the development of hydraulic cavitation, and the cavitation intensity could be indirectly controlled by adjusting the noncondensable gas content. With increasing cavitation intensity, the average bubble size decreased, and the bubble size distribution became narrower. Therefore, a high-pressure pulse generated by cavitation could effectively break bubbles. The development process of Microbubbles was studied. The main controlling factors for bubble formation were determined to be the turbulent shear force of the fluid and the collapse impact force of the cavitation group, which provides a theoretical basis for optimizing the design of bubble generators.

Generally, mineral processing plants generate a large quantity of waste in the form of fine particles. The flotation speed of mineral Microbubbles by coarse bubbles is dramatically higher than that of individual particles. The advantage of Microbubbles is due to the increase of binding efficiency of conventional bubbles with fine particles coated with Microbubbles. Here, the focus is on reducing chemicals consumption and improving recovery. After preparing a representative sample, XRF, XRD, and mineralogical analyses were performed. Then 50 experiments were selected by experimental design using the response surface method (RSM), and in the form of central Composite design (CCD) by (design expert) DX 13 software. The interactions of collector consumption, frother agent, pH, particle size, and solid percentage were investigated, and 25 experiments using typical flotation and without nano-Microbubbles and others with nano-Microbubbles were conducted. The laboratory standard limit of the collector used in the pilot plant of the Sarcheshmeh Copper copper complex is 40 g/t (25 g/t of C7240 plus 15 g/t of Z11). Here, by consuming 20 g/t of collector in the absence of nanoMicrobubbles, a recovery of 79.96% and in the presence of nanoMicrobubbles, a recovery of 80.07% was obtained, that is a 50% reduction in collector consumption and a 0.11% increase in recovery was observed. Also the laboratory standard limit of frother used in the pilot plant of Sarcheshemeh Copper Complex is 30 g/t (15 g/t of MIBC plus 15 g/t of A65). Here, by using 10 g/t of frother in the absence of nanoMicrobubbles, a recovery of 78.12%, and in the presence of nanoMicrobubbles, a recovery of 82.05% was obtained. In other words, a decrease of 66.6% in the consumption of frother and an increase of 1.93% in recovery was observed.

Microbubbles are used in ultrasound imaging, targeted drug delivery, destruction of cancerous tissues, etc. On the other hand, the demographic behaviors of small bubbles under the influence of Ultrasound have not been fully detected or studied. This study investigates the effect of the radial distribution of Sonazoid Microbubbles on frequency response.  It is shown that the optimal subharmonic response is possible by controlling the size distribution. For this reason, the numerical simulation of the dynamic behavior of a coated microbubble is performed using MATLAB coding and the modified Rayleigh-Plesset equation. The Gaussian distribution is then applied, and the frequency response is investigated. It was shown that at a constant excitation pressure of 0.4 MPa and a standard deviation of 0.2, with increasing mean radius, the fundamental response increases. The subharmonic response increases reaches a peak value and decreases. This peak value occurs for frequencies of 4,6, and 8 MHz in the mean radius of 0.8, 1 and 1.6 μm. By increasing the frequency of excitation, it is transferred to a smaller mean radius. It is also observed that the fundamental and subharmonic responses are amplified by increasing the excitation pressure. Studies show that the optimal subharmonic response can be achieved for various applications by controlling the size distribution of Microbubbles.

Introduction: Skin melanoma is one of the most invasive types of skin cancer. It accounts for about 75% of all skin cancer deaths and has not yet been definitively treated. As a result, early diagnosis and prevention of the disease is important. Much research has been done to find ways to treat and cure cancer. One of the newest methods in this field is the use of nanotechnology to detect and inhibit cancer cells. In this study, the effect of using Nano Microbubbles of Air, Oxygen and Ozone on A375 melanoma cancer cell line was evaluated. Materials and Methods: A375 cell line treated with different concentrations of Nano Microbubbles of Air, Oxygen and Ozone and were evaluated by MTT method. In order to measure cell viability, MTT plate was added to each well and then the plate was incubated. Results: According to the results of this study, a decrease in the viability of A375 cancer cells with an increase in the concentration of Oxygen and Ozone Nano Microbubbles after 24 hours indicates apoptosis and has a significant inhibition of the growth of these cells. Conclusion: The results of this study indicate that Nano Microbubbles of Oxygen and Ozone in high concentrations cause cell death of A375 cell line. The results of this study will help investigate the role of Nano Microbubbles of Air, Oxygen and Ozone in the treatment of melanoma cancer.

In the oil-gas mixture transportation system of offshore oilfields, it is of great theoretical and practical significance to study the flow characteristics of the slug flow and its suppression or elimination. In this paper, the characteristics of the slug flow and Microbubbles in a laboratory-scale rig are experimentally studied and analyzed by a multi-parameters measurement system including electrical resistance tomography (ERT), high-speed camera, and traditional pressure sensor. The suppression of the Microbubbles on the slug flow formation is further investigated. Experimental results showed that the bubbles with different sizes from the microbubble generator have different aggregation and dispersion characteristics. The Microbubbles can suppress the formation of the slug flow by increasing the liquid slug pressure and further affect the motion of the slug by enhancing the disturbance effect of the boundary layer, so as to achieve the suppression on slug flow.