Scientific and Technological Center for Unique Instrumentation of the Russian Academy of Sciences(STC UP RAS), 15 Butlerova str, Moscow 117342, Russia.
Lomonosov Moscow state University, 1 Leninskie Gory, Moscow 119991, Russia.
Ultrasonics. 2023 Jul;132:106963. doi: 10.1016/j.ultras.2023.106963. Epub 2023 Feb 22.
An acoustic microscopy method for measuring the velocity of ultrasound in the yolk and blastula of bony fish embryos at early stages of development was proposed. The yolk and blastula were approximated as a sphere and a spherical dome, respectively, consisting of a homogeneous liquid. A theoretical model of ultrasonic wave propagation through a spherical liquid drop located on a solid substrate was developed in the ray approximation. The dependence of the wave propagation time on the speed of sound in the drop, its diameter, and the position of the focus of the ultrasonic transducer has been determined. It was shown that the velocity in the drop can be found by solving the inverse problem by minimizing the discrepancy between the experimental and model spatial distributions of the propagation time, assuming that the velocity in the immersion liquid and the radius of the drop are known. The velocities in the yolk and blastula of the loach (Misgurnus fossilis) embryo at the stage of development of the middle blastula were measured in vivo using a pulsed scanning acoustic microscope operating at a central frequency of 50 MHz. The yolk and blastula radii were determined from ultrasound images of the embryo. Acoustic microscopy measurements conducted with four embryos provide velocities of the acoustic longitudinal wave in the yolk and blastula. They were measured to be 1581 ± 5 m/s and 1525 ± 4 m/s when the temperature of the liquid in the water tank was kept at 22 ± 2 °C.
提出了一种声学显微镜方法，用于测量早期发育的硬骨鱼胚胎的卵黄和囊胚中的超声速度。卵黄和囊胚分别近似为球体和球形穹顶，由均匀的液体组成。在射线近似法中，开发了一个用于通过位于固体基底上的球形液滴传播超声波的理论模型。确定了波传播时间与液滴中的声速、液滴直径以及超声换能器焦点位置的关系。结果表明，假设浸液中的速度和液滴的半径已知，可以通过最小化实验和模型传播时间空间分布之间的差异来求解反问题，从而找到液滴中的速度。使用工作频率为 50MHz 的脉冲扫描声学显微镜，对发育中期囊胚阶段泥鳅（Misgurnus fossilis）胚胎的卵黄和囊胚进行了体内测量。从胚胎的超声图像确定卵黄和囊胚的半径。对四个胚胎进行的声学显微镜测量提供了卵黄和囊胚中声纵波的速度。当水箱中的液体温度保持在 22±2°C 时，测量到卵黄和囊胚中的声速分别为 1581±5m/s 和 1525±4m/s。
