Background: Inner ear disorders, such as EH, commonly lead to hearing loss and vestibular dysfunction. EH is particularly prevalent in various inner ear diseases, including Meniere’s disease. We aimed to evaluate the effects of EH on WAI and OAEs.Objective: This study explores the potential of wideband acoustic immittance (WAI) and otoacoustic emissions (OAEs) for the early detection of changes in acoustic transmission associated with vasopressin-induced endolymphatic hydrops (EH) in a guinea pig model.Methods: We induced EH in guinea pigs via daily intraperitoneal injections of arginine vasopressin over 14 consecutive days. Auditory function was assessed using Auditory Brainstem Responses (ABR), while changes in sound energy transmission were measured using WAI and Distortion Products Otoacoustic Emissions (DPOAE).Results: Increased ABR thresholds in EH models were statistically significant (p < 0.05). After 14 days of EH induction, absorbance at 1 kHz significantly increased, whereas it significantly decreased at 4 kHz and 6 kHz (p < 0.05). DPOAE measures, both magnitude and phase, showed no significant changes (p > 0.05).Conclusion: WAI demonstrates greater sensitivity than DPOAE in the early detection of acoustic transmission alterations in EH models, suggesting its utility as a diagnostic tool in early-stage inner ear disorders.
In this study, the effect of microcrcaks strengthening on damage evolution of Al 2 TiO 5 (AT) flexible ceramics was investigated by acoustic emission (AE). Results reveal that with increasing content of ZrO 2 , the strength of AT flexible ceramics improves gradually and the strain increases at first then decreases. When the content of ZrO 2 is 12% and 8%, the strength and strain at maximum stress are increased by 154.92% and 38.27%, respectively. In addition, thanks to the “strengthening effect” of ZrTiO 4 on grain boundary microcracks, the damage development thresholds ( σ min and σ onset ), elastic modulus and fracture toughness of AT flexible ceramics modified with ZrO 2 are significantly improved. Moreover, the visible transverse cracks and matrix shedding in ATZ-0 are the most, but the cumulative AE damage events in ATZ-8 and ATZ-4 are more than ATZ-0 at late stage, for which the fracture of ZrTiO 4 glass phase and crack branching induced by ZrTiO 4 should be responsible.
Capsule-based self-healing of cementitious materials is a promising solution to improve the serviceability and to prolong the longevity of concrete structures. The successful use of mechanical triggering microcapsules to achieve cracks healing is still challenging and is closely dependent on the breakage of capsules upon crack formation . In this study, self-healing microcapsules were synthesized via complex coacervation using a styrene maleic anhydride (SMA) shell and an epoxy resin adhesive . The SMA/gelatin bi-layer wall formed with gelatin as the out layer for better trigger sensitivity under crack formation. The effects of various preparation parameters, referring to stirring rate, temperature, core-shell ratio and pH, have been investigated by characterizing the microcapsule morphology, shell thickness, size distribution, and chemical nature. The morphology demonstrates the encapsulation ability of SMA/gelatin and the spherical shape facilitates the rupture under crack formation. The elastic modulus and hardness of the microcapsules were determined using nano-indentation to assess the interfacial bonding and likelihood of mechanical triggering. Self-healing functionality of the developed microcapsules were validated in paste according to the in situ Acoustic Emission measurement.
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