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A polyacrylamide polysaccharide hydrogel (PASG) containing a nonionic surfactant of the polyoxyethylene nonylphenyl ethers series (NP14) has been adapted to the fabrication of a reusable cost-effective ultrasonic tissue-mimicking phantom for real-time visualization of the thermal lesions by high intensity focused ultrasound (HIFU) irradiation. The constructed NP14 (40% in w/v) PASG is optically transparent at room temperatures, and it turns out to be opaque white as heated over the clouding points of about 55 °C and returns to its original transparent state after cooling. The acoustic property of the proposed phantom is similar to those of human liver tissues, which includes the acoustic impedance of 1.68 Mrayls, the speed of sound of 1595 ± 5 m/s, the attenuation coefficient of 0.52 ± 0.05 dB cm−1 (at 1 MHz), the backscatter coefficient of 0.21 ± 0.09 × 10−3 sr−1 cm−1 (at 1 MHz), and the nonlinear parameter B/A of 6.4 ± 0.2. The NP14-PASG was tested to assess the characteristic information (sizes, shapes, and locations) of the thermal lesions visualized when exposed to typical HIFU fields (1.1 MHz, focal pressure up to 20.1 MPa, focal intensity 4075 W/cm2). The proposed NP14-PASG is expected to replace the existing costly BSA-PASG used for more effective testing of the performance of therapeutic ultrasonic devices based on thermal mechanisms.

This study aims to verify if the beating sound of a singing bowl synchronizes and activates brain waves during listening. The singing bowl used in this experiment produce beats at a frequency of 6.68 Hz, while it decays exponentially and lasts for about 50 s. Brain waves were measured for 5 min in the F3 and F4 regions of seventeen participants (eight males and nine females, average age 25.2) who heard the beating singing bowl sounds. The experimental results showed that the increases (up to ~251%) in the spectral magnitudes of the brain waves were dominant at the beat frequency compared to those of any other clinical brain wave frequency bands. The observed synchronized activation of the brain waves at the beating sound frequency supports that the singing bowl sound may effectively facilitate meditation and relaxation, considering that the beat frequency belongs to the theta wave region which increases in the relaxed meditation state.

Purpose To report the intraocular pressure (IOP) lowering effect of low intensity ultrasound (LIUS) on eyes of ocular hypertensive rats. Methods Continuous radiation of LIUS on ocular hypertensive eyes induced by unilateral microbeads injection was performed. A round plane ultrasound transducer operating at a frequency of 1MHz was utilized to deliver a sonication of 240mW/cm2 in acoustic intensity. LIUS was treated on both eyes of rats (n=5) simultaneously and the IOP measurements of treated group were compared with those of untreated group (n=5). Results The mean IOPs of LIUS‐treated eyes and un‐treated eyes were 9.4 ± 0.55 mmHg and 9.6 ± 0.55 mmHg, respectively at baseline. After an intracameral injection of microbeads, IOPs were reached to 18.6 ± 4.037 mmHg and 22.8 ± 3.493 mmHg (p=0.580) at 3 days after microbeads injection. Then the IOPs were decreased by 39.47 % and 9.68 % at 1 day after a single sonication. Conclusion These results showed that continuous low intensity ultrasound suppresses the IOP elevation in experimental glaucoma model using microbeads injection into anterior chamber. By the reason of its non‐invasiveness and repeatability, LIUS could be an alternative method for glaucoma treatment in near future.