Matching Items (10)
Description
New technologies enable the exploration of space, high-fidelity defense systems, lighting fast intercontinental communication systems as well as medical technologies that extend and improve patient lives. The basis for these technologies is high reliability electronics devised to meet stringent design goals and to operate consistently for many years deployed in the field. An on-going concern for engineers is the consequences of ionizing radiation exposure, specifically total dose effects. For many of the different applications, there is a likelihood of exposure to radiation, which can result in device degradation and potentially failure. While the total dose effects and the resulting degradation are a well-studied field and methodologies to help mitigate degradation have been developed, there is still a need for simulation techniques to help designers understand total dose effects within their design. To that end, the work presented here details simulation techniques to analyze as well as predict the total dose response of a circuit. In this dissertation the total dose effects are broken into two sub-categories, intra-device and inter-device effects in CMOS technology. Intra-device effects degrade the performance of both n-channel and p-channel transistors, while inter-device effects result in loss of device isolation. In this work, multiple case studies are presented for which total dose degradation is of concern. Through the simulation techniques, the individual device and circuit responses are modeled post-irradiation. The use of these simulation techniques by circuit designers allow predictive simulation of total dose effects, allowing focused design changes to be implemented to increase radiation tolerance of high reliability electronics.
ContributorsSchlenvogt, Garrett (Author) / Barnaby, Hugh (Thesis advisor) / Goodnick, Stephen (Committee member) / Vasileska, Dragica (Committee member) / Holbert, Keith E. (Committee member) / Arizona State University (Publisher)
Created2014
Description
Spasticity is a neurological disorder in which a target group of muscles remain in a contracted state. In addition to interfering with the function of these muscles, spasticity causes chronic pain and discomfort. Often found in patients with cerebral palsy, multiple sclerosis, or stroke history, spasticity affects an estimated twelve million people worldwide. Not only does spasticity cause discomfort and loss of function, but the condition can lead to contractures, or permanent shortenings of the muscle and connective tissue, if left untreated. Current treatments for spasticity are primarily different forms of muscle relaxant pharmaceuticals. Almost all of these drugs, however, carry unwanted side effects, including total muscle weakness, liver toxicity, and possible dependence. Additionally, kinesiotherapy, conducted by physical therapists at rehabilitation clinics, is often prescribed to people suffering from spasticity. Since kinesiotherapy requires frequent practice to be effective, proper treatment requires constant professional care and clinic appointments, discouraging patient compliance. Consequently, a medical device that could automate relief for spasticity outside of a clinic is desired in the market. While a number of different dynamic splints for hand spasticity are currently on the market, research has shown that these devices, which simply brace the hand in an extended position, do not work through any mechanism to decrease spastic tension over time. Two methods of temporarily reducing spasticity that have been observed in clinical studies are cryotherapy, or the decrease of temperature on a target area, and electrotherapy, which is the delivery of regulated electrical pulses to a target area. It is possible that either of these mechanisms could be incorporated into a medical device aimed toward spastic relief. In fact, electrotherapy is used in a current market device called the SaeboStim, which is advertised to help stroke recovery and spastic reduction. The purpose of this paper is to evaluate the viability of a potential spastic relief device that utilizes cryotherapy to a current and closest competitor, the SaeboStim. The effectiveness of each device in relieving spasticity is reviewed. The two devices are also compared on their ability to address primary customer needs, such as convenience, ease of use, durability, and price. Overall, it is concluded that the cryotherapy device more effectively relieves hand spasticity in users, although the SaeboStim's smaller size and better convenience gives it market appeal, and reveals some of the shortcomings in the preliminary design of the cryotherapy device.
ContributorsWiedeman, Christopher Blaise (Author) / Kleim, Jeffrey (Thesis director) / Buneo, Christopher (Committee member) / W.P. Carey School of Business (Contributor) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Current wound closure technology is limited, and lacks key elements \u2014 such as the formation of an immediate seal \u2014 that could otherwise resolve some of the common and life threatening complications associated with certain surgeries. Previous research has produced nanosealants capable of providing that immediate seal through the use of laser activation with a near infrared laser. Here, we have developed a biocompatible suture utilizes the same mechanics to provide the tensile strength needed to replace or supplement existing suture lines. Laser activated tissue integrating sutures (LATIS), are shown to have 75% of the tensile strength of commercially available PGA sutures, while still exhibiting the same laser mediated localized heating effect at power densities of as low as 1.6 W/cm2. LATIS has been shown to reach the temperature ranges needed for protein interdigitation, but suffers from low wet mechanical strength. Preparatory steps or solvents for chemical crosslinking generally dehydrate LATIS sutures, causing a shriveling effect that weakens the overall mechanical strength of the suture. To resolve this, a new method of drying, by which LATIS sutures are dried under tension on a suspended platform, has been shown to decrease control suture strength, but restore the strength of chemically treated LATIS sutures to the level of control sutures or above. These promising results suggest that follow-up work with chemical cross-linkers may produce the increases in LATIS wet strength that are needed for its implementation in deeper tissue surgeries.
ContributorsChang, Andy (Author) / Rege, Kaushal (Thesis director) / Goklany, Sheba (Committee member) / School of Molecular Sciences (Contributor) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
A great deal of research has been done on communication barriers between patient and doctor, but due to the complexity of the relationship, little successful solutions have been suggested to bridge interdisciplinary communication between the two persons. This project explores a solution to aid both patient and doctor as they seek to communicate with each other regarding the patient's prognosis and treatment with a medical device. By creating a website, the information found therein can be accessed in the doctor's office by using a smartphone or tablet so that both patient and doctor can use it as a resource before, during, and after a doctor's visit. The website, Medical Devices 4 U (MD4U), gives background information on a large selection of medical devices, allows primary sources to share their information with potential consumers of the medical device, permits users to ask questions and comment on other user's comments, and gives a list of questions that a patient can ask a healthcare professional during a doctor's visit. In this report, the nature of doctor and patient communication is exposed and the steps taken to alleviate the communication barriers by way of creating a website are explained.
ContributorsHalls, Sarah Koy (Author) / Spano, Mark (Thesis director) / Garcia, Antonio (Committee member) / Brandon, Tedd (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2013-05
Description
In a world in which technologies proliferate at a rapid rate, it is no surprise that the medical device industry has grown in leaps and bounds. This surge in medical technology, especially implantable medical technology, has altered the modern operating room, transforming surgery from a technique-driven activity into a technology-driven profession. This reliance upon technologies has fostered close ties between physicians and the medical device industry and within this relationship, medical device representatives play an integral role. This paper will investigate the relationship that exists between physicians and the medical device industry along with the potential conflicts of interest that may result due to this relationship. I will focus in particular on orthopedic medical devices due to media attention as a result of a 2007 Department of Justice settlement involving the leading orthopedic companies. This case proved instrumental in highlighting previously unknown instances in which conflicts of interest were occurring in the medical device industry.
ContributorsLove, Kailey (Author) / Robert, Jason (Thesis director) / Marchant, Gary (Committee member) / Buchholtz, Stephanie (Committee member) / Barrett, The Honors College (Contributor) / School of International Letters and Cultures (Contributor) / School of Life Sciences (Contributor) / School for the Science of Health Care Delivery (Contributor)
Created2014-05
Description
Ketone levels give an insight into the bodies metabolism. People with epilepsy or people dieting may want to keep their levels high, whereas type one diabetics or those recovering from eating disorders may want to keep their levels low. Current ketone detection methods involve blood samples or urinalysis. A ketone (acetone) biosensor was fabricated to detect levels in human breath, providing a noninvasive way to quickly and accurately detect ketone levels in the body.
ContributorsHendricks, Asher (Author) / Forzani, Erica (Thesis director) / Osorio Perez, Oscar (Committee member) / Wang, Shaopeng (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor)
Created2023-05
Description
Presented in this thesis are two projects that fall under the umbrella of magnetically actuated electronics and robotics for medical applications. First, magnetically actuated tunable soft electronics are discussed in Chapter 2. Wearable and implantable soft electronics are clinically available and commonplace. However, these devices can be taken a step further to improve the lives of their users by adding remote tunability. The four electric units tested were planar inductors, axial inductors, capacitors and resistors. The devices were made of polydimethylsiloxane (PDMS) for flexibility with copper components for conductivity. The units were tuned using magnets and mobile components comprised of iron filings and ferrofluid. The characteristic properties examined for each unit are as follows: inductance and quality factor (Q-factor) for inductors, capacitance and Q-factor for capacitors, and impedance for resistors. There were two groups of tuning tests: quantity effect and position effect of the mobile component. The position of the mobile component had a larger effect on each unit, with 20-23% change in inductance for inductors (from 3.31 µH for planar and 0.44 µH for axial), 12.7% from 2.854 pF for capacitors and 185.3% from 0.353 kΩ for resistors.
Chapter 3 discusses a magnetic needle tracking device with operative assistance from a six degree-of-freedom robotic arm. Traditional needle steering faces many obstacles such as torsional effects, buckling, and small radii of curvature. To improve upon the concept, this project uses permanent magnets in parallel with a tracking system to steer and determine the position and orientation of the needle in real time. The magnet configuration is located at the end effector of the robotic arm. The trajectory of the end effector depends on the needle’s path, and vice versa. The distance the needle travels inside the workspace is tracked by a direct current (DC) motor, to which the needle is tethered. Combining this length with the pose of the end effector, the position and orientation of the needle can be calculated. Simulation of this tracking device has shown the functionality of the system. Testing has been done to confirm that a single magnet pulls the needle through the phantom tissue.
Chapter 3 discusses a magnetic needle tracking device with operative assistance from a six degree-of-freedom robotic arm. Traditional needle steering faces many obstacles such as torsional effects, buckling, and small radii of curvature. To improve upon the concept, this project uses permanent magnets in parallel with a tracking system to steer and determine the position and orientation of the needle in real time. The magnet configuration is located at the end effector of the robotic arm. The trajectory of the end effector depends on the needle’s path, and vice versa. The distance the needle travels inside the workspace is tracked by a direct current (DC) motor, to which the needle is tethered. Combining this length with the pose of the end effector, the position and orientation of the needle can be calculated. Simulation of this tracking device has shown the functionality of the system. Testing has been done to confirm that a single magnet pulls the needle through the phantom tissue.
ContributorsEdwards, Dakota (Author) / Marvi, Hamidreza (Thesis advisor) / Lee, Hyunglae (Committee member) / Berman, Spring (Committee member) / Arizona State University (Publisher)
Created2020
Description
Needle steering is an extension of manually inserted needles that allows for maneuverability within the body in order to avoid anatomical obstacles and correct for undesired placement errors. Research into needle steering predominantly exploits interaction forces between a beveled tip and the medium, controlling the direction of forces by applying rotations at the base of the needle shaft in order to steer. These systems are either manually or robotically advanced, but have not achieved clinical relevance due to a multitude of limitations including compression effects in the shaft that cause undesired tissue slicing, torsional friction forces and deflection at tissue boundaries that create control difficulties, and a physical design that inherently restricts the workspace. While most improvements into these systems attempt to innovate the needle design or create tissue models to better understand interaction forces, this paper discusses a promising alternative: magnetic needle steering. Chapter 2 discusses an electromagnetic needle steering system that overcomes all aforementioned issues with traditional steering. The electromagnetic system advances the needle entirely magnetically so it does not encounter any compression or torsion effects, it can steer across tissue-interfaces at various angles of attack (90, 45, 22.5°) with root-mean-square error (RMSE) of 1.2 mm, achieve various radii of curvature as low as 10.2 mm with RMSE of 1.4 mm, and steer along complex 3D paths with RMSE as low as 0.4 mm. Although these results do effectively prove the viability of magnetic steering, the electromagnetic system is limited by a weak magnetic field and small 33mm cubic workspace. In order to overcome these limitations, the use of permanent magnets, which can achieve magnetic forces an order of magnitude larger than similarly sized electromagnetics, is investigated. The needle will be steered toward a permanent magnet configuration that is controlled by a 6 degree-of-freedom robotic manipulator. Three magnet configurations were investigated, two novel ideas that attempt to create local maximum points that stabilize the needle relative to the configuration, and one that pulls the needle toward a single magnet. Ultimately, the last design was found to be most viable to demonstrate the effectiveness of magnetic needle steering.
ContributorsPetras, Alex (Author) / Marvi, Hamidreza (Thesis advisor) / Yong, Sze Z. (Committee member) / Ross, Heather M. (Committee member) / Arizona State University (Publisher)
Created2020
Description
The adaptive artificial-intelligence (AI) medical device industry is a novel industry in the United States offering innovations to the healthcare field. The rapid expansion of this industry in recent years has drawn attention from multiple stakeholders causing a heated debate about how to introduce these innovations into the market while maintaining patient safety and treatment efficacy. Since early 2019, the U.S. Food and Drug Administration (FDA) has been releasing statements in regards to the improvement of regulation for this new technology, but has yet to take further actions. Dilemmas including 1) a difficult regulatory process, 2) a heightening financial burden and 3) looming liability issues, are reasons adaptive AI medical devices have struggled to be advanced. By conducting a thorough analysis of these 3 issues, recognizing the intricacies of them separately and together, this study develops a better understanding of the landscape adaptive AI technology is facing and provides a clearer picture for the future of the industry.
ContributorsOgden, Ravyn Nicole (Author) / Coursen, Jerry (Thesis director) / Pizziconi, Vincent (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Realtime understanding of one’s complete metabolic state is crucial to controlling weight and managing chronic illnesses, such as diabetes. This project represents the development of a novel breath acetone sensor within the Biodesign Institute’s Center for Bioelectronics and Biosensors. The purpose is to determine if a sensor can be manufactured with the capacity to measure breath acetone concentrations typical of various levels of metabolic activity. For this purpose, a solution that selectively interacts with acetone was embedded in a sensor cartridge that is permeable to volatile organic compounds. After 30 minutes of exposure to a range of acetone concentrations, a color change response was observed in the sensors. Requiring only exposure to a breath, these novel sensor configurations may offer non-trivial improvements to clinical and at-home measurement of lipid metabolic rate.
ContributorsDenham, Landon (Author) / Forzani, Erica (Thesis director) / Mora, Sabrina Jimena (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor)
Created2022-05