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- Creators: Harrington Bioengineering Program
Description
An improved system for wireless neurostimulation was investigated through the design and development of sub-millimeter piezoelectric devices. The devices build on prior work in the lab, which was limited by device size and required surgical implantation. A method of manufacturing sub-mm devices was developed, and utilized to construct this new design. The device frequency response was characterized and its resonant modes and output voltages determined through a Fast Fourier Transform. The fundamental thickness mode frequency was found to be 15.4MHz with a corresponding 10.25mV amplitude, and a longitudinal resonant frequency of 3.1Mhz with a corresponding 2.2mV amplitude across a 50Ω resistor. The high miniaturization of the device holds promise for future work for creating an injectable, wireless system for the treatment of neurological disorders.
ContributorsCatchings, Michael Thomas (Author) / Towe, Bruce (Thesis director) / Muthuswamy, Jitendran (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
This purpose of this study was to develop reliable methods for ultrasound measurements of skeletal muscle architecture, and to identify which specific quadriceps measurements most closely relate to peak isometric torque of the leg extensors. These data were obtained as part of a larger research study and consist of 9 total subjects (4 males, 5 females; age (30.6 ± 13.6yr). Ultrasound images for muscle thickness and pennation angle were obtained for each subject during two separate testing days (separated by 5-10 days). Images were acquired at various anatomical sites of the quadriceps and each image was analyzed using Image J software. Quadriceps muscles assessed for muscle thickness and pennation angle included the vastus lateralis (VL), and vastus intermedius (VI), while rectus femoris (RF) was assessed only for muscle thickness. Peak isometric torque measurements were obtained at 60 degrees of knee angle for knee extension using an isokinetic dynamometer. Results show that the methods chosen for ultrasound measurement produced reliable inter-day results for muscle thickness and pennation angle. VL muscle thickness and pennation angle obtained at the lateral site corresponding to 39% of leg length was highly related to peak isometric torque for knee extension. The results of this study identify specific measurement sites that are related to muscle function. In addition, these data further validate that ultrasound measurement is reliable to measure muscle thickness and pennation angle in skeletal muscle.
ContributorsSkotak, Nathaniel James (Author) / Dickinson, Jared (Thesis director) / Vidt, Meghan (Committee member) / Luden, Nick (Committee member) / School of Nutrition and Health Promotion (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
Nerve endings are particularly difficult to target during peripheral nerve block (PNB) procedures, so ultrasound-guided needles are of immense importance to guarantee safe and efficient delivery of the anesthetic to the target nerve. Despite significant progress in needle visualization with ultrasound imaging, there are still several factors that lead to poor needle visibility, the main factor being insertion angle. Introducing cavities and holes in the needle at specific intervals through pitting corrosion may alter the ultrasonic feedback from the sensor, thereby resulting in improved clarity of the reconstructed image. The purpose of this experiment is to investigate the effectiveness of two novel pitting designs on the needle’s visibility under ultrasound. Two different designs and two depths of cut are tested in a 22 factorial that is blocked by insertion angle: a uniform and a non-uniform design. Needles were cut using a Plain Jane and Igor laser cutter and imaged using a GE Logig e BT12 ultrasound imaging machine. Images were compared visually and objectively by using a tool in Photoshop to calculate the luminosity of the needle. Two videos were also taken capturing the difficulty of imaging surgical needles. Results showed that pitting had a major impact on needle visibility at 30° and a marginal impact at 0°. The videos supported these results as it was considerably more difficult to locate the control needle than the experimental needle. This suggests the probe must be in a specific plane with the control needle for it to be visible while the experimental needle is much more lenient. Results from the two depths of cuts showed similar results in that the designs which were cut twice were more visible than their counterparts at 30°. The study showed that pitting has positive effects on needle visibility; it improves visibility by increasing the luminescence of the needle and by decreasing its sensitivity to probe position.
ContributorsTze, David (Author) / Muthuswamy, Jit (Thesis director) / Towe, Bruce (Committee member) / Harrington Bioengineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
In an embolization therapy, a material is injected into a vessel to block blood flow. While this therapy is useful in starving cancerous cells it can be dangerous, with some blockades in the brain dislodging and causing strokes or blindness. Currently, embolic materials on the market such as metal coils, balloons, and liquid embolic agents do not have a quick removal procedure. An ultrasound cleavable material could be removed in an emergency situation without invasive surgery. The primary goal of this research is to design and synthesize a polymer that can be broken down by high intensity focused ultrasound (HIFU). Initially, we have tested the ultrasound sensitive qualities on PPODA-QT hydrogel, a common embolic agent, but the gel showed no physical change after HIFU exposure. It is theorized that PNIPAAm combined with HIFU sensitive monomers can develop a temperature and ultrasound sensitive embolic agent. In our studies, poly(NIPAAm-co-tBa) had a slight lower critical solution temperature (LCST) change of about 2˚C from before to after HIFU while the study with poly(NIPAAm-co-ACL-BME) and PPODA-QT showed no change in LCST.
ContributorsLein, Karolena (Author) / Vernon, Brent (Thesis director) / Pal, Amrita (Committee member) / Harrington Bioengineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2020-05