Patient-specific RF safety assessment in MRI: Progress in creating surface-based human head and shoulder models

The interaction of electromagnetic (EM) fields with the human body during magnetic resonance imaging (MRI) is complex and subject specific. MRI radiofrequency (RF) coil performance and safety assessment typically includes numerical EM simulations with a set of human body models. The dimensions of mesh elements used for discretization of the EM simulation domain must be adequate for correct representation of the MRI coil elements, different types of human tissue, and wires and electrodes of additional devices. Examples of such devices include those used during electroencephalography, transcranial magnetic stimulation, and transcranial direct current stimulation, which record complementary information or manipulate brain states during MRI measurement. The electrical contact within and between tissues, as well as between an electrode and the skin, must also be preserved. These requirements can be fulfilled with anatomically correct surface-based human models and EM solvers based on unstructured meshes. Here, we report (i) our workflow used to generate the surface meshes of a head and torso model from the segmented AustinMan dataset, (ii) head and torso model mesh optimization for three-dimensional EM simulation in ANSYS HFSS, and (iii) several case studies of MRI RF coil performance and safety assessment

The Doppler Wind Temperature Sensor (DWTS) Flight Evaluation and Experiments (TES-16,17)

The Doppler Wind and Temperature Sounder instrument (DWTS) developed by Global Atmospheric Technologies and Sciences (GATS) is a simple yet powerful tool with the potential to become a new window through which the study of upper atmosphere dynamics can occur. Based around a defense-grade infrared camera peering through a static gas cell used as a scanning spectral filter, a DWTS instrument can infer wind velocities and kinetic temperatures throughout the stratosphere and lower thermosphere. The DWTS achieves this scanning by measuring the induced Doppler shift and Doppler broadening of emissions as they pass through the DWTS field of view (Gordley, Marshall, 2011). The DWTS holds promise in improving accuracy in weather determination among other terrestrial benefits, and the core technology can be easily adapted to study the dynamics of other planetary atmospheres. In partnership with GATS, NOAA, and other collaborators, NASA Ames and the Nano-Orbital Workshop (NOW) group have been working to evaluate the DWTS instrument on orbit and optimize it as a flexible payload for nanosatellites. The first mission selected for DWTS technical evaluation is preparing for flight in early 2024, which will be followed by a more capable science mission in 2025, with both missions being part of the TES-n/NOW heritage flight series. The first rapid technology demonstration flight, TES-16/DWTS-A, will demonstrate a single DWTS instrument in an approximately 2U payload volume. With an estimated power consumption of 50 watts, the instrument will maintain the imaging sensor plane at 80K during instrument performance evaluation periods using an integrated Stirling cryocooler. Data from DWTS will be captured and processed via a NOW-designed custom data interface unit before being transmitted via S-band radio back to select ground stations, with instrument command and control maintained via L-band global-coverage radio. The subsequent TES-17/DWTS-B mission will be a dedicated science mission tasked with validating the instrument’s full altitude coverage capabilities, currently estimated from 20 to 200 km during both day and night. This new atmospheric observational capability will come from a single small satellite equipped with three DWTS imagers, each hosting a different gas cell chemistry, to form a complete instrument. The intention of this flight series, and one of NASA’s interests in this instrument, is not only to advance Earth atmospheric dynamics, but to advance a Martian atmospheric study instrument as well (Colaprete, Gordley, et al) which, if successful, would greatly further understanding of Martian atmospheric dynamics. This document describes the flight series in detail, including challenges facing the TES-16 flight tests and the projected challenges and application of Mars study. Additional detail regarding the possible applications of a Cognitive Communication technique in current flight development by NOW collaborators at the NASA Glenn Research Center is also discussed, including the implications of using an automated User Initiated Service (UIS) protocol to maximize the data collected per orbit

Providing Small Satellite Communications Using the NOAA GOES Satellite

The results of a LEO to GEO communication system using the NOAA GOES (Geostationary Operational Environmental Satellite) DCS (Data Collection System) are presented. The DCS system was designed to collect climate-related data from remote unmanned stations. Data are uplinked to one of the two operational satellites via an aggregated link to the NASA Wallops Facility. The modified LEO transmitter, one of the 7 transmitters flown on the TechEdSat-8 nano-satellite, is designed to compensate for the Doppler effects to ensure the communication link. Though a slow data rate initially, the system may offer another convenient means of transmitting data from LEO to ground stations any time during an orbit. The experiment will allow for an assessment of this as a future communication system development path - as well as the very interesting extension of the system for a comparable system at Mars for climatic surveys from ground stations (hence, a Mars radio)

TechEdSat-N and ETC Series

This presentation address the issues and how to involve students in the process of develping, building and certifying flight hardware for ISS and development of Mars missions

Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU

Contains fulltext : 172380.pdf (publisher's version ) (Open Access

COMPARING MUSCLE ACTIVATION BETWEEN STATIONARY, DYNAMIC AND ON-WATER ROWING

C. Murbach, K. York, L. Howard, T. Klaudt, B. Higginson Gonzaga University, Spokane, WA Off-water rowing ergometry methods such as dynamic and stationary ergometry are common solutions used by rowing coaches when faced with environmental conditions. There has been extensive research done on the kinematics and overall force production of the different ergometer types. However, little research has been done on the comparison between stationary, dynamic and on-water rowing. PURPOSE: This study investigated whether dynamic or stationary ergometry has more comparable muscle activation to on-water rowing. METHODS: 9 collegiately trained male rowers performed three trials of two-minute rowing at 20 strokes per minute (spm) using a repeated measures counterbalanced design. The three trials consisted of stationary erging (SE), dynamic erging (DE) and on-water rowing (OW). Electromyographic data was taken from the right gastrocnemius (GS), biceps femoris (BF), vastus lateralis (VL) and rectus femoris (RF). RESULTS: The mean activation for the GS was 33% higher during SE than OW (p = .026), similarly the BF had a 45% higher mean muscle activation during SE than OW (p = .003). VL mean activation was 33% higher during DE than OW (p = .010)and 56% higher during SE than OW (p = .001). RF was found to a 50% higher max muscle activation during SE than OW (p =.044). RF also had a significantly shorter time to peak activation during SE (29.0 ± 12.9 %) than both OW (37.2 ± 14.8%) (p = .032)and DE (52.2 ± 14.0 %) (p = .001). CONCLUSIONS: This research indicated that there may be fewer differences seen between on-water rowing and dynamic ergometry, as compared to stationary ergometry which may indicate that dynamic ergometry is a better training tool for coaches and athletes to utilize as a substitute for when on-water rowing is not available