Experimental investigation on the characteristics of the shock wave emitted by the cavitation bubble near the air bubble

This study explores the mitigation of cavitation damage in hydraulic engineering through air entrainment. The primary aim is to experimentally analyze the shock wave characteristics emitted by cavitation bubbles adjacent to air bubbles affixed to a tube nozzle. The schlieren optical system is utilized to visualize the shock wave, while a hydrophone measures its pressure. Experiments are conducted on cavitation bubbles induced by the spark-generated method in the vicinity of air bubbles, varying the dimensionless distances and sizes of the air bubbles. The results indicate that (1) The introduction of an air bubble noticeably changes the morphology, kinematic behavior, and shock wave features of the cavitation bubble. (2) Four distinct shock wave patterns are identified based on the quantity and shape of the shock wave, with variations in the cavitation bubble's collapsing behavior and shock wave characteristics across different patterns. (3) The dimensionless distance γ and size δ exert significant influence on the shock wave's quantity, pressure peak, shape, and energy. With γ decreases or δ increases, the shock wave quantity increases while the shock wave intensity decreases. This investigation of the interaction between cavitation bubbles and air bubbles is essential for elucidating the mechanism through which air entrainment mitigates cavitation damage.

Corneal Effect of Air Bubble After Phacoemulsification

Objectives

The aim of the study was to investigate the effect of air bubble on the cornea at the end of the cataract surgery with phacoemulsification.

Methods

This prospective and case-control study included 71 patients with air bubble injected into the anterior chamber at the end of the operation and 63 age-sex-matched control patients without air bubble. Endothelial cell density (ECD), coefficient of variation (CV), hexagonality rate (HEX), and central corneal thickness (CCT) measurements were taken using non-contact specular microscopy preoperatively and at 1-day, 1-week, and 1-month postoperatively.

Results

No significant difference was determined between the groups preoperatively in respect of mean visual acuity, anterior chamber depth, ECD, CV, HEX, and CCT values (p>0.05). The intraoperative average ultrasound power, effective phaco time, and ultrasound time values were similar (p>0.05). The CCT value was lower in the study group than in the control group on post-operative day 1 (p=0.012), but similar at 1 week and 1 month (p=0.102, p=0.330, respectively). No significant difference was determined between the groups in mean visual acuity, anterior chamber reaction, ECD, CV, and HEX values at 1-day, 1-week, and 1-month postoperatively (p>0.05).

Conclusion

Air bubble may be used as an alternative method to reduce corneal edema on the 1st post-operative day. According to the results, although air bubble has no detrimental effect, there is also seen to be no protective effect on the corneal endothelium.

Cough-induced bubbles formation in the heart: Is it related with a poor prognosis?

In current practice, it is not well-known whether the development of air bubbles spontaneously in the heart during routine transthoracic echocardiography examination has a clinical consequence. Even though there have been published case reports regarding the formation of air bubbles due to iatrogenic reasons, we could not find a case of a patient demonstrating spontaneous air bubbles formation due to only coughing. Thus, in this report, we present a case of an adult patient who had unexpected air bubbles in the heart after coughing. Furthermore, the patient experienced a catastrophic cerebrovascular accident after diagnosing such an event in the same day. We thought that spontaneously occurring air bubbles in the heart might have resulted in cerebrovascular accident by passing through patent foramen ovale, which we have diagnosed after we had seen that the spontaneously occurred air bubbles had also appeared in left chambers. To our knowledge, this might be the first case of such a patient in the literature. <Learning objective: The appearance of cough-induced air bubbles in the left heart might be a precursor to peripheral air embolism, and thus, predictive of very poor prognosis. Thus, medical workers should be aware of this poor finding.>.

The synergistic effect of focused ultrasound and biophotonics to overcome the barrier of light transmittance in biological tissue

Optical technology is a tool to diagnose and treat human diseases. Shallow penetration depth caused by the high optical scattering nature of biological tissues is a significant obstacle to utilizing light in the biomedical field. In this paper, light transmission enhancement in the rat brain induced by focused ultrasound (FUS) was observed and the cause of observed enhancement was analyzed. Both air bubbles and mechanical deformation generated by FUS were cited as the cause. The Monte Carlo simulation was performed to investigate effects on transmission by air bubbles and finite element method was also used to describe mechanical deformation induced by motions of acoustic particles. As a result, it was found that the mechanical deformation was more suitable to describe the transmission change according to the FUS pulse observed in the experiment.

Movement of air bubbles under various liquids using bioinspired conical surfaces

Gas bubbles are of interest in various applications. The study of their movement is of importance. Gas bubbles are typically formed under liquids. Movement of liquid droplets on bioinspired conical surfaces is known to be facilitated by the Laplace pressure gradient. These conical surfaces, with various wettabilities and shapes, can also be used to move gas bubbles. In this study, effect of various liquids on movement of air bubble under liquid was studied. It was found that liquids with high surface tension and high density are more efficient in moving air bubbles. High surface tension and higher density increases the Laplace pressure gradient force and the buoyancy force, respectively, which drive under liquid air bubbles.

Contact angles and movement of air bubbles on bioinspired conical surfaces

Air bubbles are of interest in various applications. The study of their formation, interaction with underlying surfaces, and their movement is of importance. Bioinspired conical surfaces have been known to exhibit Laplace pressure gradient which facilitates the movement of liquid droplets. These conical surfaces, with various geometries and wettabilities, can be used to regulate gas bubble movement. In this study, contact angles of air bubbles and their movement on various conical surfaces were investigated. The effect of parameters including cone orientation, air bubble volume, tip angle, and wettability on air bubble movement were studied. A smaller tip angle cone with high wettability was found to be most efficient for an air bubble movement.

Spontaneous transport of air bubbles on bioinspired superhydrophilic triangular patterns

Air bubbles are interfacial fluid dynamics phenomena in many natural and technological processes. The dynamics of air bubbles is of interest in many applications. In this study, to facilitate the transport of air bubbles, triangular patterns were used, inspired by conical spines of cactus, which develop Laplace pressure gradient. The effect of various wettabilities and included angles of the triangular patterns on air bubble transport were investigated. The air bubbles can climb even if a pattern is mounted on a vertical plane. The effect of the size of air bubbles was also investigated.

Embryo flash migration in fresh and frozen embryo transfers for day 3 and day 5 embryos

OBJECTIVE

The aim of this study is to evaluate the embryo flash migration after 60 min from embryo transfer in fresh and frozen cycles.

DESIGN

80 fresh and 81 frozen embryo transfers implemented Ondokuz Mayıs University between December 2017 and May 2018 were included in this prospective study. The fresh transfers performed at day 3 embryos as the frozen transfers were day 5 embryos. The distance between the embryo and the fundus was measured in the sagittal plane within 1 min of the transfer. After 60 min of bed rest the distance between the air bubble and the fundus was measured. The transfers were divided into three groups based on the migration of the embryos after the transfer. Embryos were classified as static if they were within 15 mm of their initial position. If they moved more than 15 mm towards the cervix or more than 15 mm towards the fundus, it was classified as cervical and fundal, respectively.

RESULTS

There was a statistically significant difference in embryo flash movements between frozen and fresh transfers (p < 0.05). In fresh transfers 48 patients (%60.0) were cervical, 14 patients (%17.5) were static and 18 patients (22.5%) were fundal. In frozen embryo transfers 31 patients (38.3%) were cervical, 31 patients (38.3%) were fundal and 19 (23.5%) patients were static.

CONCLUSION

We found that cervical migration is lower in frozen transfers than in fresh transfers. This result may be related with the day of embryo or the endometrium in fresh or frozen cycles. Because in this study the embryos transferred were day 3 in fresh cycle and day 5 in frozen cycle. In frozen transfers there was not any significant difference in embryo position between pregnant and non-pregnant group. But in fresh transfers the cervical migration was significantly high in non-pregnant patients (p < 0.05).

Importance of air bubbles in the core of coated pellets: Synchrotron X-ray microtomography allows for new insights

High-resolution X-ray microtomography was used to get deeper insight into the underlying mass transport mechanisms controlling drug release from coated pellets. Sugar starter cores were layered with propranolol HCl and subsequently coated with Kollicoat SR, plasticized with 10% TEC. Importantly, synchrotron X-ray computed microtomography (SR-μCT) allowed direct, non-invasive monitoring of crack formation in the film coatings upon exposure to the release medium. Propranolol HCl, as well as very small sugar particles from the pellets' core, were expulsed through these cracks into the surrounding bulk fluid. Interestingly, SR-μCT also revealed the existence of numerous tiny, air-filled pores (varying in size and shape) in the pellet cores before exposure to the release medium. Upon water penetration into the system, the contents of the pellet cores became semi-solid/liquid. Consequently, the air-pockets became mobile and fused together. They steadily increased in size (and decreased in number). Importantly, "big" air bubbles were often located in close vicinity of a crack within the film coating. Thus, they play a potentially crucial role for the control of drug release from coated pellets.

Morphological changes and viability of primary cultured human ocular trabecular meshwork cells after exposure to air

PURPOSE

To investigate the possible toxic effect of air exposure for an in vitro model of primary human ocular trabecular meshwork cells (HTM).

METHODS

HTM were isolated from five donor eyes and cultivated at 37 °C. After reaching confluence the cells were seeded on two well chamber slides. The chamber slides were turned upside down in a Petri culture dish full of culture medium and filled with air using a 5 ml syringe, starting this way the exposure of the cells to the air. Subsequently they were placed in the incubation chamber at 37 °C. Six groups of HTM cultures were set up: group 1 consisted of samples in which HTM were exposed to air for 30 min, group 2 for 1 h, group 3 for 3 h, group 4 for 6 h, group 5 for 12 h and group 6 for 24 h.

RESULTS

At 3 h after exposure, the morphology of the cells was still intact, at 6 h few cells appeared deformed and exhibited characteristics of more senescent cells. At 12 h after exposure to air the HTM cells started losing their typical morphology and appeared enlarged and compromised. Viability was superior to 94% in groups 1-3 while for groups 4, 5, 6 it was 82.7%, 39.5% and 12.7% respectively.

CONCLUSION

The toxic effect of air exposure for the studied in vitro model of HTM is not significant for the time period of one to three hours. However it starts reducing viability and alternating morphology 6 h after exposure until the time period of 24 h, where the percentage of living cells is drastically decreased. Therefore, we suggest that the use of an air bubble especially in glaucomatous patients should be applied with caution.

Thromboembolic Events Associated with Electrolytic Detachment of Guglielmi Detachable Coils and Target Coils : Comparison with Use of Diffusion-Weighted MR Imaging

Objective

The purpose of this study was to retrospectively evaluate and compare the incidence of diffusion-weighted image (DWI) lesions between the Guglielmi detachable coil (GDC) and the Target coil for treating unruptured intracranial aneurysm.

Methods

From 2010 to 2011, consecutive 222 patients with an intracranial aneurysm underwent coil embolization. Inclusion criterias were : 1) unruptured intracranial aneurysm, 2) one or more GDC or Target coils used with or without other coils, 3) DWI examination within 24 hours after coiling, and 4) coiling performed without a balloon or stent.

Results

Ninety patients (92 cases) met the inclusion criteria. DWI lesions were detected in 55 (61.1%) of 90 patients. In the GDC group (n=44), DWI lesions were detected in 31 (70.5%). The average number of DWI lesions was 5.0±8.7 (mean±SD; range, 1-40) in aneurysm-related territory. In the Target coil group (n=48), DWI lesions were detected in 24 (50.0%). The number of DWI lesion was 2.1±5.4 (range, 1-32) in aneurysm-related territory. There was no significant correlation between a number of coils and DWI lesions. No significant differences were also observed in the number of DWI lesions in each group.

Conclusion

The GDC and Target coils, which have an electrolytic detachable system, showed no differences in the incidence of DWI lesion.

In vitro observation of air bubbles during delivery of various detachable aneurysm embolization coils

Objective

Device- or technique-related air embolism is a drawback of various neuro-endovascular procedures. Detachable aneurysm embolization coils can be sources of such air bubbles. We therefore assessed the formation of air bubbles during in vitro delivery of various detachable coils.

Materials and Methods

A closed circuit simulating a typical endovascular coiling procedure was primed with saline solution degassed by a sonification device. Thirty commercially available detachable coils (7 Axium, 4 GDCs, 5 MicroPlex, 7 Target, and 7 Trufill coils) were tested by using the standard coil flushing and delivery techniques suggested by each manufacturer. The emergence of any air bubbles was monitored with a digital microscope and the images were captured to measure total volumes of air bubbles during coil insertion and detachment and after coil pusher removal.

Results

Air bubbles were seen during insertion or removal of 23 of 30 coils (76.7%), with volumes ranging from 0 to 23.42 mm³ (median: 0.16 mm³). Air bubbles were observed most frequently after removal of the coil pusher. Significantly larger amounts of air bubbles were observed in Target coils.

Conclusion

Variable volumes of air bubbles are observed while delivering detachable embolization coils, particularly after removal of the coil pusher and especially with Target coils.