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Device for making measurements of organs in living specimens and recording movements of organs is described. System uses series of ultrasonic pulses beamed into body of animal and reflected echo pulses are picked up by transducers and recorded. Diagram of equipment required and method of application is included.
A train of ultrasonic pulses is beamed into the body of an animal. Organs intercepted by the beam reflect echo pulses following each transmitted pulse. An electronic gate with a variable width and a variable time delay relative to the transmitted pulse is utilized for selecting echoes derived from other organs or portions of organs. The integral of the echo signals received within the first half of the gate period is subtracted from a corresponding integral of the echo signal received during the second half of the gate to derive an error signal for controlling the time delay of the gate. In this manner, the selected echo signal is always maintained in the center of the gate.
The acquisition of crew biomedical data has been an important task on manned space missions. The monitoring of biowastes from the crew to support water and mineral balance studies and endocrine studies has been a valuable part of this activity. This paper will present a review of waste management systems used in past programs. This past experience will be cited as to its influence on the Shuttle design. Finally, the Shuttle baseline waste management system and the proposed Shuttle biomedical measurement and sampling systems will be presented.
A day-by-day summary of selected data collected during the experiment is presented. The clinical and environmental data are presented in a mission-day format along with a tabulation of biomedical measurements whose values exceed three standard deviations from the preflight measurements.
Digital camera pixels measure image intensities by converting incident light energy into an analog electrical current, and then digitizing it into a fixed-width binary representation. This direct measurement method, while conceptually simple, suffers from limited dynamic range and poor performance under extreme illumination --- electronic noise dominates under low illumination, and pixel full-well capacity results in saturation under bright illumination. We propose a novel intensity cue based on measuring inter-photon timing, defined as the time delay between detection of successive photons. Based on the statistics of inter-photon times measured by a time-resolved single-photon sensor, we develop theory and algorithms for a scene brightness estimator which works over extreme dynamic range; we experimentally demonstrate imaging scenes with a dynamic range of over ten million to one. The proposed techniques, aided by the emergence of single-photon sensors such as single-photon avalanche diodes (SPADs) with picosecond timing resolution, will have implications for a wide range of imaging applications: robotics, consumer photography, astronomy, microscopy and biomedical imaging.
In space, there is a need to monitor astronauts' vital signs and assess their readiness to perform specific tasks during a mission. Currently, NASA does not have the capability to noninvasively monitor crew for extended periods of time. The Canadian Space Agency is working with the Psychophysiology Lab at NASA ARC to determine if the Astroskin could be used as a solution to this problem. Astroskin, a commercially available garment with built-in biosensors, can be comfortably worn under clothing or a spacesuit and relay information to the crewman's own mobile device. Data can also be sent wirelessly to the on-board Exploration Medical System. To determine if Astroskin meets requirements for health monitoring, it must first be validated in spaceflight analog environments. In the current study Astroskin data will be compared to traditional biomedical instrument measures of electrocardiography (ECG), respiration rate, and systolic blood pressure. The data will be recorded during Autogenic Feedback Training Exercise (AFTE), which is a type of physiological self-regulation training designed for astronauts. The data will also be recorded during simulations of the Orion spacecraft re-entry. The results to date suggest that Astroskin is a suitable ambulatory monitoring system that allows astronauts to self-diagnose and self-regulate adverse autonomic nervous system responses to sustained exposure to microgravity of spaceflight.
Biomedical tool measures cutaneous sensory perception by allowing consistent application of regular and determinable pressure to skin of the individual. Device is of relatively simple construction, inexpensive to manufacture, and easy to operate.
The Experiment Support System is a switchboard system with displays and controls. It routes electrical power to experiments M092, M093, and M171 equipment; gaseous nitrogen to the Blood Pressure Measurement System; receives biomedical data from all related equipment; routes the conditioned data signals to the Airlock Module Telemetry System and also displays (in digital or analog from) portions of that data which the crewmen must see to complete the experiment successfully. The Experiment Support System is interfaced to the M131 control panel to transfer conditioned data to the Airlock Module Telemetry System.
The primary objective of this study is to determine which biomedical and human factors measurements must be made aboard a space station to assure adequate evaluation of the astronaut's health and performance during prolonged space flights. The study has employed, where possible, a medical and engineering systems analysis to define the pertinent life sciences and space station design parameters and their influence on a measurement program. The major areas requiring evaluation in meeting the study objectives include a definition of the space environment, man's response to the environment, selection of measurement and data management techniques, experimental program, space station design requirements, and a trade-off analysis with final recommendations. The space environment factors that are believed to have a significant effect on man were evaluated. This includes those factors characteristic of the space environment (e. g. weightlessness, radiation) as well as those created within the space station (e. g. toxic contaminants, capsule atmosphere). After establishing the general features of the environment, an appraisal was made of the anticipated response of the astronaut to each of these factors. For thoroughness, the major organ systems and functions of the body were delineated, and a determination was made of their anticipated response to each of the environmental categories. A judgment was then made on the medical significance or importance of each response, which enabled a determination of which physiological and psychological effects should be monitored. Concurrently, an extensive list of measurement techniques and methods of data management was evaluated for applicability to the space station program. The various space station configurations and design parameters were defined in terms of the biomedical and human factors requirements to provide the measurements program. Research design of experimental programs for various station configurations, mission durations, and crew sizes were prepared, and, finally, a trade-off analysis of the critical variables in the station planning was completed with recommendations to enhance the confidence in the measurement program.
Electronic sensor accurately measures and controls flow of plasma, whole blood, or drugs in solution. Since sensor does not directly contact fluid, it does not have to be sterilized. It is compatible with disposable bottles, tubes, and hypodermic needles widely used in hospitals. Only modification necessary is in tube, which must contain two small metal inserts, spaced to fit in curved thermistor plates.
The study reported here has presented a measurement data pool for the determination of biomedical and behavioral effects of long-term exposure to weightlessness. This includes measures, techniques, equipment, and requirements in terms of weight, power, volume, time, crew activities, subsystem interfaces and experimental programs and designs, and confidence ratings for their effectiveness for determining weightlessness effects.
A coated-wire ion-selective electrode for measuring ionic calcium was developed, in collaboration with Teknektron Sensor Development Corporation (TSDC). This coated wire electrode sensor makes use of advanced, ion-responsive polyvinyl chloride (PVC) membrane technology, whereby the electroactive agent is incorporated into a polymeric film. The technology greatly simplifies conventional ion-selective electrode measurement technology, and is envisioned to be used for real-time measurement of physiological and environment ionic constituents, initially calcium. A primary target biomedical application is the real-time measurement of urinary and blood calcium changes during extended exposure to microgravity, during prolonged hospital or fracture immobilization, and for osteoporosis research. Potential advanced life support applications include monitoring of calcium and other ions, heavy metals, and related parameters in closed-loop water processing and management systems. This technology provides a much simplified ionic calcium measurement capability, suitable for both automated in-vitro, in-vivo, and in-situ measurement applications, which should be of great interest to the medical, scientific, chemical, and space life sciences communities.
Improved solid-state microanemometer suitable for measuring flows in variety of biomedical, industrial, and other applications. Small size, unique design, and one-piece construction provides combination of short response time, structural rigidity, optimal dissipation of heat, and versatility in application. Device includes four integral sensing resistors exposed to flow measured and serves as hot-film anemometer subunits. Sensing resistors connected to external excitation-and-measurement circuits operating in any of standard hot-film-anemometer modes; constant input voltage, constant input current, or constant resistance with feedback.
Significant challenges exist in efficient data analysis of most advanced experimental and observational techniques because the collected signals often include unwanted contributions, such as background and signal distortions, that can obscure the physically relevant information of interest. To address this, we have developed a self-supervised machine-learning approach for source separation using a dual implicit neural representation framework that jointly trains two neural networks: one for approximating distortions of the physical signal of interest and the other for learning the effective background contribution. Our method learns directly from the raw data by minimizing a reconstruction-based loss function without requiring labeled data or pre-defined dictionaries. We demonstrate the effectiveness of our framework by considering a challenging case study involving large-scale simulated, as well as experimental, momentum-energy-dependent inelastic neutron scattering data in a four-dimensional parameter space, characterized by heterogeneous background contributions and unknown distortions to the target signal. The method is found to successfully separate physically meaningful signals from a complex or structured background even when the signal characteristics vary across all four dimensions of the parameter space. An analytical approach that informs the choice of the regularization parameter is presented. Our method offers a versatile framework for addressing source separation problems across diverse domains, ranging from superimposed signals in astronomical measurements to structural features in biomedical image reconstructions.
An important task of in vivo polarimetric glucose sensing is to find an appropriate way to optically access the aqueous humor of the human eye. In this paper two different approaches are analyzed theoretically and applied to the eye model of Le Grand. First approach is the tangential path of Cote, et al. (G.L. Cot6, M.D. Fox, and R.B. Northrop: Noninvasive Optical Polarimetric Glucose Sensing Using a True Phase Measurement Technique. IEEE Transactions on Biomedical Engineering, vol. 39, no. 7, pp. 752-756, 1992.) and the second is a new scheme of this paper of applying Brewster reflection off the eye lens.
Understanding how the effects of long-duration spaceflight (~6-months) might increase fracture risk in the younger-aged, physically-fit astronaut is challenging. Most of our skeletal data have been acquired from long-duration astronauts, crewmembers who typically serve on 120-180 day missions aboard the International Space Station (ISS). Astronaut biomedical data are predominantly 2-d measurements from DXA scans because this is a required clinical test at Johnson Space Center. Data from these clinical tests, and some data from research studies, are what NASA evaluates to define a risk for fracture in astronauts, both during a mission and long-term health. To date, the agency considers the risk for fracture during spaceflight to be of high (severe) consequence but of low probability (<0.1%) while the risk for fracture in during long-term health to be of medium consequence (interventions available) and medium probability (<1%). These risks are considered acceptable. Notably, there are minimal data to suggest that postflight fractures in long-duration astronauts are directly due to spaceflight exposure. Analyses by NASA epidemiologists and by biomedical engineers suggest that postflight fracture incidence in astronauts is consistent with a physically-active terrestrial population with no exposure to spaceflight. The epidemiological data to-date may be considered insufficient (low # and younger-aged subjects, limited follow-up time) to assess a fracture risk with reliability. In the absence of fracture evidence to substantiate a risk, it may be more useful to maintain astronauts at baseline (preflight) level of skeletal health during a mission. This lecture will present data from astronauts that affirms that 1) the maintenance of skeletal health during the future 3-year Mars mission will require an anti-resorptive therapy and 2) the risk for fracture during long-term health cannot be defined by the DXA clinical test alone.
In this paper we discuss a novel radio frequency (RF) telemetry concept for biomedical applications. The concept consists of a miniaturized spiral inductor/antenna for bio-MEMS sensors and an external pick-up antenna integrated into a handheld device. The measured relative signal strength in the presence of biological phantoms ranged from 5.9 to 7.5 dB for antenna separations of 5 and 10 cm. These relative signal strengths are easily measurable, therefore validating the RF telemetry concept for biomedical applications.
The danger of disuse osteoporosis under weightless condition in space led to extensive research into measurements of bone stiffness and mass by the Biomedical Research Division of Ames and Stanford University. Through its Technology Utilization Program, NASA funded an advanced SOBSA, a microprocessor-controlled bone probe system. SOBSA determines bone stiffness by measuring responses to an electromagnetic shaker. With this information, a physician can identify bone disease, measure deterioration and prescribe necessary therapy. The system is now undergoing further testing.