Experimental design and analysis of a gyroelastic beam

Division of Higher Technical Education of MexicoPublished versio

Continuous Restoration of the Human Vestibulo-Ocular Reflex Using a Multichannel Vestibular Implant

Bilateral loss of vestibular sensation causes blurry vision during head movement, postural instability, chronic unsteadiness, and an increased fall risk. Individuals who fail to compensate despite rehabilitation therapy and cessation of exacerbating medications have no adequate treatment options. Inspired by the success of cochlear implants in restoring hearing, prosthetic stimulation of vestibular afferent neurons to encode head motion has been investigated as a potential treatment. Until now, no human had been continuously stimulated for more than a day, and human responses had not been assessed using 3-dimensional (3D) binocular oculography, without which one cannot determine whether an implant independently stimulates each of the implanted ear’s three semicircular canals. We report 3D binocular vestibulo-ocular reflex (VOR) responses in four human subjects with bilateral vestibular loss who were each implanted with a system designed to provide long-term motion-modulated prosthetic stimulation via electrodes in the semicircular canals of one ear. Initiation of prosthetic stimulation evoked nystagmus that decayed within 30 minutes. Stimulation targeting one canal produced 3D VOR responses aligned with that canal’s anatomic axis, while targeting canal pairs reliably yielded responses aligned with a vector sum of individual responses. Over 8 weeks of continuous use, modulated electrical stimulation produced robust and stable VOR responses that grew predictably with stimulus intensity and aligned approximately with any specified 3D head rotation axis. Combining mechanical and electrical stimulation enhanced low frequency responses. These results demonstrate that a vestibular implant can partially restore 3D inner ear sensation to individuals disabled by vestibular loss. Lastly, we show that temporal discretization inherent to cochlear implant signal processing has minimal effects on evoked responses, motivating a future combined device

Development of an Ultra-Sensitive and Flexible Piezoresistive Flow Sensor Using Vertical Graphene Nanosheets

© 2020, © 2020, The Author(s). This paper suggests development of a flexible, lightweight, and ultra-sensitive piezoresistive flow sensor based on vertical graphene nanosheets (VGNs) with a mazelike structure. The sensor was thoroughly characterized for steady-state and oscillatory water flow monitoring applications. The results demonstrated a high sensitivity (103.91 mV (mm/s)−1) and a very low-velocity detection threshold (1.127 mm s−1) in steady-state flow monitoring. As one of many potential applications, we demonstrated that the proposed VGNs/PDMS flow sensor can closely mimic the vestibular hair cell sensors housed inside the semicircular canals (SCCs). As a proof of concept, magnetic resonance imaging of the human inner ear was conducted to measure the dimensions of the SCCs and to develop a 3D printed lateral semicircular canal (LSCC). The sensor was embedded into the artificial LSCC and tested for various physiological movements. The obtained results indicate that the flow sensor is able to distinguish minute changes in the rotational axis physical geometry, frequency, and amplitude. The success of this study paves the way for extending this technology not only to vestibular organ prosthesis but also to other applications such as blood/urine flow monitoring, intravenous therapy (IV), water leakage monitoring, and unmanned underwater robots through incorporation of the appropriate packaging of devices.[Figure not available: see fulltext.

A real-time research platform to study vestibular implants with gyroscopic inputs in vestibular deficient subjects

Researchers have succeeded in partly restoring damaged vestibular functionality in several animal models. Recently, acute interventions have also been demonstrated in human patients. Our previous work on a vestibular implant for humans used predefined stimulation patterns; here we present a research tool that facilitates motion-modulated stimulation. This requires a system that can process gyroscope measurements and send stimulation parameters to a hybrid vestibular-cochlear implant in real-time. To match natural vestibular latencies, the time from sensor input to stimulation output should not exceed 6.5 ms. We describe a system based on National Instrument's CompactRIO platform that can meet this requirement and also offers floating point precision for advanced transfer functions. It is designed for acute clinical interventions, and is sufficiently powerful and flexible to serve as a development platform for evaluating prosthetic control strategies. Amplitude and pulse frequency modulation to predetermined functions or sensor inputs have been validated. The system has been connected to human patients, who each have received a modified MED-EL cochlear implant for vestibular stimulation, and patient tests are ongoing

Technology 2000, volume 1

The purpose of the conference was to increase awareness of existing NASA developed technologies that are available for immediate use in the development of new products and processes, and to lay the groundwork for the effective utilization of emerging technologies. There were sessions on the following: Computer technology and software engineering; Human factors engineering and life sciences; Information and data management; Material sciences; Manufacturing and fabrication technology; Power, energy, and control systems; Robotics; Sensors and measurement technology; Artificial intelligence; Environmental technology; Optics and communications; and Superconductivity

Evaluating footwear “in the wild”: Examining wrap and lace trail shoe closures during trail running

Trail running participation has grown over the last two decades. As a result, there have been an increasing number of studies examining the sport. Despite these increases, there is a lack of understanding regarding the effects of footwear on trail running biomechanics in ecologically valid conditions. The purpose of our study was to evaluate how a Wrap vs. Lace closure (on the same shoe) impacts running biomechanics on a trail. Thirty subjects ran a trail loop in each shoe while wearing a global positioning system (GPS) watch, heart rate monitor, inertial measurement units (IMUs), and plantar pressure insoles. The Wrap closure reduced peak foot eversion velocity (measured via IMU), which has been associated with fit. The Wrap closure also increased heel contact area, which is also associated with fit. This increase may be associated with the subjective preference for the Wrap. Lastly, runners had a small but significant increase in running speed in the Wrap shoe with no differences in heart rate nor subjective exertion. In total, the Wrap closure fit better than the Lace closure on a variety of terrain. This study demonstrates the feasibility of detecting meaningful biomechanical differences between footwear features in the wild using statistical tools and study design. Evaluating footwear in ecologically valid environments often creates additional variance in the data. This variance should not be treated as noise; instead, it is critical to capture this additional variance and challenges of ecologically valid terrain if we hope to use biomechanics to impact the development of new products

A Systematic Review and Meta-Analysis of the Incidence of Injury in Professional Female Soccer

The epidemiology of injury in male professional football is well documented and has been used as a basis to monitor injury trends and implement injury prevention strategies. There are no systematic reviews that have investigated injury incidence in women’s professional football. Therefore, the extent of injury burden in women’s professional football remains unknown. PURPOSE: The primary aim of this study was to calculate an overall incidence rate of injury in senior female professional soccer. The secondary aims were to provide an incidence rate for training and match play. METHODS: PubMed, Discover, EBSCO, Embase and ScienceDirect electronic databases were searched from inception to September 2018. Two reviewers independently assessed study quality using the Strengthening the Reporting of Observational Studies in Epidemiology statement using a 22-item STROBE checklist. Seven prospective studies (n=1137 professional players) were combined in a pooled analysis of injury incidence using a mixed effects model. Heterogeneity was evaluated using the Cochrane Q statistic and I2. RESULTS: The epidemiological incidence proportion over one season was 0.62 (95% CI 0.59 - 0.64). Mean total incidence of injury was 3.15 (95% CI 1.54 - 4.75) injuries per 1000 hours. The mean incidence of injury during match play was 10.72 (95% CI 9.11 - 12.33) and during training was 2.21 (95% CI 0.96 - 3.45). Data analysis found a significant level of heterogeneity (total Incidence, X2 = 16.57 P < 0.05; I2 = 63.8%) and during subsequent sub group analyses in those studies reviewed (match incidence, X2 = 76.4 (d.f. = 7), P <0.05; I2 = 90.8%, training incidence, X2 = 16.97 (d.f. = 7), P < 0.05; I2 = 58.8%). Appraisal of the study methodologies revealed inconsistency in the use of injury terminology, data collection procedures and calculation of exposure by researchers. Such inconsistencies likely contribute to the large variance in the incidence and prevalence of injury reported. CONCLUSIONS: The estimated risk of sustaining at least one injury over one football season is 62%. Continued reporting of heterogeneous results in population samples limits meaningful comparison of studies. Standardising the criteria used to attribute injury and activity coupled with more accurate methods of calculating exposure will overcome such limitations

Reports to the President

A compilation of annual reports for the 1986-1987 academic year, including a report from the President of the Massachusetts Institute of Technology, as well as reports from the academic and administrative units of the Institute. The reports outline the year's goals, accomplishments, honors and awards, and future plans