(a) ATILA finite element analysis software was used to establish a 1/8th model of a single element rectangular cymbal transducer. (b) Using ATILA, the predicted cap displacement when operated at the first ceramic resonance was modeled. The axial displacement of the rectangular cymbal caps is indicated with the color bar and the displacement is in meters.
(Color online) (a) A single element rectangular cymbal transducer was constructed from titanium cap molded from a shaping die. Caps were bonded to the ceramics using epoxy. (b) Multielement arrays were made by electrically connecting the transducers and potting them in polyurethane. The rectangular array (right) was designed to be comparable in size to the circular array (left).
(Color online) (a) Illustration and (b) photograph of the animal setup for the transdermal insulin transport experiments. With the rabbit placed in a lateral recumbent position, a -thick, water-tight standoff filled with insulin was arranged between the thigh and the array.
(Color online) (a) Measured and ATILA predicted admittance (magnitude and phase) of a rectangular cymbal transducer in air. (b) Transmitting voltage response (TVR) comparison of a rectangular and circular array. Except for the dips, the rectangular array has a greater TVR than the circular array. The dips in the TVR for the rectangular array were due to asymmetrical modes in the device possibly caused by uneven bonding. (c) Parallel tuned ratios for both arrays, which indicates an improved efficiency for the rectangular array over the circular array.
Temporal peak intensity profiles of a (a) circular and (b) rectangular array at a plane from the array face. With a similar spatial peak temporal peak intensity for both arrays , it is evident that the rectangular array produces a broader spatial intensity field pattern than the circular array. The grayscale bar in decibels indicates the intensity field normalized to the peak intensity.
(Color online) Over a period of for the control group, the average glucose level increased (i.e., more hyperglycemic) to a maximum of . While the blood glucose level of the rabbits decreased from the insulin with ultrasound exposure using both arrays, the decrease was greater using the rectangular array. Statistically significant differences ( values , indicated by asterisks) were observed using the rectangular array at 45, 60, 75, and , while the only statistically significant difference observed using the circular array occurred at .
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