Matching Items (267)
Description
The primary motor cortex (M1) plays a vital role in motor planning and execution, as well as in motor learning. Baseline corticospinal excitability (CSE) in M1 is known to increase as a result of motor learning, but less is understand about the modulation of CSE at the pre-execution planning stage due to learning. This question was addressed using single pulse transcranial magnetic stimulation (TMS) to measure the modulation of both baseline and planning CSE due to learning a reach to grasp task. It was hypothesized that baseline CSE would increase and planning CSE decrease as a function of trial; an increase in baseline CSE would replicate established findings in the literature, while a decrease in planning would be a novel finding. Eight right-handed subjects were visually cued to exert a precise grip force, with the goal of producing that force accurately and consistently. Subjects effectively learned the task in the first 10 trials, but no significant trends were found in the modulation of baseline or planning CSE. The lack of significant results may be due to the very quick learning phase or the lower intensity of training as compared to past studies. The findings presented here suggest that planning and baseline CSE may be modulated along different time courses as learning occurs and point to some important considerations for future studies addressing this question.
ContributorsMoore, Dalton Dale (Author) / Santello, Marco (Thesis director) / Kleim, Jeff (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2015-05
Description
Although wind turbine bearings are designed to operate 18-20 years, in the recent years premature failure among these bearings has caused this life to reduce to as low as a few months to a year. One of the leading causes of premature failure called white structure flaking is a mechanism that was first cited in literature decades ago but not much is understood about it even today. The cause of this mode of failure results from the initiation of white etched cracks (WECs). In this report, different failure mechanisms, especially premature failure mechanisms that were tested and analyzed are demonstrated as a pathway to understanding this phenomenon. Through the use of various tribometers, samples were tested in diverse and extreme conditions in order to study the effect of these different operational conditions on the specimen. Analysis of the tested samples allowed for a comparison of the microstructure alterations in the tested samples to the field bearings affected by WSF.
ContributorsSharma, Aman (Author) / Foy, Joseph (Thesis director) / Adams, James (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2015-05
Description
The intervertebral disc goes through degenerative changes with age, which leads to disc thinning, bulging, or herniation. Spinal fusion treatments are ineffective as they cause quicker degeneration of adjacent discs and fail in nearly 20% of cases, so researchers have turned to tissue-engineering biocompatible intervertebral discs for transplantation. However novel and effective as this may seem, these transplanted discs still show evidence of degeneration after just 5 years. I hypothesize that these discs are degenerating due to a blockage of the cartilaginous endplates post-transplantation that is hindering nutrient transport through the intervertebral disc. In order to test this hypothesis, I developed a mathematical model of nutrient transport through the intervertebral disc in one diurnal daily loading cycle. This model was used to simulate open endplates and blocked endplates and then compare differences in nutrient concentration and nutrient transport to the center of the disc. Results from the math model simulations were then compared to in vitro experimental data collected in lab to verify the findings on a physiological level. Results showed significant differences, both in vitro and in the model, between nutrient transport in open endplates vs blocked endplates, lending support to the original hypothesis. This study only presents preliminary results, but could hold the key to preventing future disc degeneration post-transplantation.
ContributorsMunter, Bryce Taylor (Author) / Santello, Marco (Thesis director) / Caplan, Michael (Committee member) / Giers, Morgan (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2015-05
Description
This is a study of the adaptive behaviors of individuals with Autism Spectrum Disorder using the Vineland II Adaptive Behavioral Scale (VABS-II). This scale was used to determine the overall functioning level of individuals with Autism Spectrum Disorder at the beginning, and will be used at the end, of a year-long study beginning at Arizona State University. This larger study is determining what the effects are, if any, of a combination of nutritional and dietary treatments in individuals with Autism Spectrum Disorder. However, this paper only examines the VABS-II results of forty-three participants in the study, as well as their hand-grip strength. It was found that individuals with Autism Spectrum Disorder are substantially delayed in all four domains (communication, daily living skills, social skills, and motor skills) of adaptive behaviors measured by the VABS-II, particularly in communication. This study will be completed in May 2013, when it will be determined what the effects of these treatments are, if any.
ContributorsAdams, Rebecca (Author) / Ingram-Waters, Mary (Thesis director) / Krajmalnik-Brown, Rosa (Committee member) / Pollard, Elena (Committee member) / Barrett, The Honors College (Contributor)
Created2012-05
Description
Clean water for drinking, food preparation, and bathing is essential for astronaut health and safety during long duration habitation of the International Space Station (ISS), including future missions to Mars. Despite stringent water treatment and recycling efforts on the ISS, it is impossible to completely prevent microbial contamination of onboard water supplies. In this work, we used a spaceflight analogue culture system to better understand how the microgravity environment can influence the pathogenesis-related characteristics of Burkholderia cepacia complex (Bcc), an opportunistic pathogen previously recovered from the ISS water system. The results of the present study suggest that there may be important differences in how this pathogen can respond and adapt to spaceflight and other low fluid shear environments encountered during their natural life cycles. Future studies are aimed at understanding the underlying mechanisms responsible for these phenotypes.
ContributorsKang, Bianca Younseon (Author) / Nickerson, Cheryl (Thesis director) / Barrila, Jennifer (Committee member) / Ott, Mark (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
The effect of conflicting sensorimotor memories on optimal force strategies was explored. Subjects operated a virtual object controlled by a physical handle to complete a simple straight-line task. Perturbations applied to the handle induced a period of increased error in subject accuracy. After two blocks of 33 trials, perturbations switched direction, inducing increased error from the previous trials. Subjects returned after a 24-hour period to complete a similar protocol, but beginning with the second context and ending with the first. Interference from the first context on each day caused an increase in initial error for the second (P < 0.05). Following the rest period, subjects showed retention of the sensorimotor memory from the previous day through significantly decreased initial error (P = 3x10-6). However, subjects showed an increase in forces for each new context resulting from a sub-optimal motor strategy. Higher levels of total effort (P < 0.05) and a lack of separation between force values for opposing and non-opposing digits (P > 0.05) indicated a strategy that used more energy to complete the task, even when rates of learning appeared identical or improved. Two possible mechanisms for this lack of energy conservation have been proposed.
ContributorsSmith, Michael David (Author) / Santello, Marco (Thesis director) / Kleim, Jeffrey (Committee member) / Harrington Bioengineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
This research examines the presentation of ASD in fictional children's literature. The goal is to use the research collected to determine what symptoms of ASD are receiving coverage versus what is not being covered but needs to be in a children's book about ASD. This was accomplished by first consulting background literature on ASD before examining 40 children's books about characters on the spectrum. It was found that girls on the spectrum received less coverage than boys did, and that most books conformed to one of two types: looking at ASD through the eyes of a neurotypical child and looking at it through the eyes of a child who has it. This led to the proposed idea of a book about a girl on the spectrum that would alternate between her point of view and the point of view of her neurotypical friend, and the subsequent draft of said book.
ContributorsAnderson, Sarah (Contributor) / Baldini, Cajsa (Contributor) / Adams, James (Contributor) / Barrett, The Honors College (Contributor)
Created2014-12
Description
This project aims to use the shape memory alloy nitinol as the basis for a biomimetic actuator. These actuators are designed to mimic the behavior of organic muscles for use in prosthetic and robotic devices. Actuator characterization included in the project examines the force output,electrical properties, and other variables relevant to actuator design.
ContributorsNoe, Cameron Scott (Author) / LaBelle, Jeffrey (Thesis director) / Santello, Marco (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2014-05
Description
The semiconductor industry looks to constantly improve the efficiency of research and development in order to reduce costs and time to market. One such method was designed in order to decrease time spent inducing warpage in integrated circuits in an Intel research process. Intel's Atom product line seeks to compete with ARM architecture by entering the mobile devices CPU market. Due to the fundamental differences between the Atom's Bonnell architecture and the ARM architecture, the Intel Atom product line must utilize such improved research and development methods. Until power consumption is drastically lowered while maintaining processing speed, the Atom product line will not be able to effectively break into the mobile devices CPU market.
ContributorsLandseidel, Jack Adam (Author) / Adams, James (Thesis director) / Krause, Stephen (Committee member) / Anwar, Shahriar (Committee member) / Barrett, The Honors College (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Materials Science and Engineering Program (Contributor)
Created2013-05
Description
The characteristics possessed by undergraduates who have enjoyed success in an intern position are defined. Through an interview process, four traits were identified: multitasking, strong team work understanding, an inquisitive nature, and application of a cross-disciplinary mindset. An exposition of how these four traits are employed to ensure success in an internship setting is then given. Finally, a personal account of a project with Intel is expounded upon. This project addressed the unoptimized characterization test time of an Intel package quality control process. It improved throughput by developing a parallel testing method by increasing package carrier capacity and utilizing simultaneous testing. The final design led to a 4x increase of throughput rate.
ContributorsHusein, Sebastian Saint Tsei (Author) / Adams, James (Thesis director) / Krause, Stephen (Committee member) / Jarrell, Joseph (Committee member) / Barrett, The Honors College (Contributor) / Materials Science and Engineering Program (Contributor)
Created2013-05