ABSTRACT
Objective: To observe vascular smooth muscle cell morphological changes induced by ultrasound combined with microbubbles by Atomic Force Acoustic Microscopy (AFAM). Methods: A7r5 rat aortic smooth muscle cells were divided into groups: control group (without ultrasonic irradiation, no micro bubbles) and US+MB group (45 kHz, 0.4 W/cm2 ultrasound irradiate for 20 seconds with a SonoVue™ concentration of [(56-140)×105/mL]. Cell micro-morphological changes (such as topographic and acoustic prognosis) were detected, before and after ultrasound destruction by AFAM. Results: In cell morphology, smooth muscle cells were spread o and connected to each another by fibers. At the center of the cell, the nuclear area had a rough surface and was significantly elevated from its surroundings. The cytoskeletal structure of the reticular nucleus and cytoplasm in the morphology of A7r5 cells (20 μ m × 20 μ m) were clear before microbubble intervention. After acoustic exciting, the cell structure details of the acoustic image were improved with better resolution, showing the elasticity of different tissues. In the acoustic image, the nucleus was harder, more flexible and uneven compared with the cytoplasm. Many strong various-sized echo particles were stuck on the rough nuclear membrane's substrate surface. The nuclear membrane did not have a continuous smooth surface; there were many obstructions (pores). After ultrasound-intervention was combined with microbubbles, the dark areas of the A7r5 cell images was increased in various sizes and degrees. The dark areas showed the depth or low altitudes of the lower regions, suggesting regional depressions. However, the location and scope of the acoustic image dark areas were not similar to those found in the topographic images. Therefore, it was likely that the dark areas, both from the topographic and acoustic images, were sound-holes. In addition, some cell nuclei become round in different degrees after irradiation. Conclusions: Atomic force microscopy and acoustic excitation method can noninvasively and completely display a cell's structure, connections and elastic properties at a nano scale in just several minutes. The dark areas, both from the topographic and acoustic images, may be sound-holes; therefore, it would be helpful if these sound-holes were found. These findings provide a relationship between cell apoptosis after ultrasound and microbubble ultrasound irradiation, and the sound-hole effect.
ABSTRACT
OBJECTIVE@#To observe vascular smooth muscle cell morphological changes induced by ultrasound combined with microbubbles by Atomic Force Acoustic Microscopy (AFAM).@*METHODS@#A7r5 rat aortic smooth muscle cells were divided into groups: control group (without ultrasonic irradiation, no micro bubbles) and US+MB group (45 kHz, 0.4 W/cm(2) ultrasound irradiate for 20 seconds with a SonoVue™ concentration of [(56-140)×10(5)/mL]. Cell micro-morphological changes (such as topographic and acoustic prognosis) were detected, before and after ultrasound destruction by AFAM.@*RESULTS@#In cell morphology, smooth muscle cells were spread o and connected to each another by fibers. At the center of the cell, the nuclear area had a rough surface and was significantly elevated from its surroundings. The cytoskeletal structure of the reticular nucleus and cytoplasm in the morphology of A7r5 cells (20 μ m × 20 μ m) were clear before microbubble intervention. After acoustic exciting, the cell structure details of the acoustic image were improved with better resolution, showing the elasticity of different tissues. In the acoustic image, the nucleus was harder, more flexible and uneven compared with the cytoplasm. Many strong various-sized echo particles were stuck on the rough nuclear membrane's substrate surface. The nuclear membrane did not have a continuous smooth surface; there were many obstructions (pores). After ultrasound-intervention was combined with microbubbles, the dark areas of the A7r5 cell images was increased in various sizes and degrees. The dark areas showed the depth or low altitudes of the lower regions, suggesting regional depressions. However, the location and scope of the acoustic image dark areas were not similar to those found in the topographic images. Therefore, it was likely that the dark areas, both from the topographic and acoustic images, were sound-holes. In addition, some cell nuclei become round in different degrees after irradiation.@*CONCLUSIONS@#Atomic force microscopy and acoustic excitation method can noninvasively and completely display a cell's structure, connections and elastic properties at a nano scale in just several minutes. The dark areas, both from the topographic and acoustic images, may be sound-holes; therefore, it would be helpful if these sound-holes were found. These findings provide a relationship between cell apoptosis after ultrasound and microbubble ultrasound irradiation, and the sound-hole effect.
ABSTRACT
Objective To develop an improved DIC (digital image correlation) algorithm suitable for measuring large ROM (range of motion) of the cervical spine, as traditional DIC algorithm is not capable of accurately measuring ROM of the cervical spine due to its large rotation angles. Methods An algorithm which allowed rotation of the subset window was proposed to achieve robust correlation matching in the measurement. A new iterative variable, which represented the orientation of the subset, was introduced and incorporated in the Newton-Raphson iteration method together with the position variables (x,y). By assigning an initial guess to these variables individually, the precise location and rotation angle could be determined in the deformed image. The precision of the proposed method was evaluated by translation and rotation experiments. ResultsThe translation experiment confirmed that the proposed method had the same accuracy as the traditional DIC, and the displacement measurement accuracy was within 0.5%. While the rotation experiment indicated that the proposed method could measure the deformation at any angles with precision less than 0.5°. The method was then applied to the measurement of ROM of cervical spine subjected to compressive loads and received good results. Conclusions Compared with the traditional DIC algorithm, the proposed method can achieve accurate measurement with large ROM for cervical spine tests with different loads, and provide an effective means for assessing the stability and physiological activities of cervical spine.