415 research outputs found

    Extracting Cardiac Information From Medical Radar Using Locally Projective Adaptive Signal Separation

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    Electrocardiography is the gold standard for electrical heartbeat activity, but offers no direct measurement of mechanical activity. Mechanical cardiac activity can be assessed non-invasively using, e.g., ballistocardiography and recently, medical radar has emerged as a contactless alternative modality. However, all modalities for measuring the mechanical cardiac activity are affected by respiratory movements, requiring a signal separation step before higher-level analysis can be performed. This paper adapts a non-linear filter for separating the respiratory and cardiac signal components of radar recordings. In addition, we present an adaptive algorithm for estimating the parameters for the non-linear filter. The novelty of our method lies in the combination of the non-linear signal separation method with a novel, adaptive parameter estimation method specifically designed for the non-linear signal separation method, eliminating the need for manual intervention and resulting in a fully adaptive algorithm. Using the two benchmark applications of (i) cardiac template extraction from radar and (ii) peak timing analysis, we demonstrate that the non-linear filter combined with adaptive parameter estimation delivers superior results compared to linear filtering. The results show that using locally projective adaptive signal separation (LoPASS), we are able to reduce the mean standard deviation of the cardiac template by at least a factor of 2 across all subjects. In addition, using LoPASS, 9 out of 10 subjects show significant (at a confidence level of 2.5%) correlation between the R-T-interval and the R-radar-interval, while using linear filters this ratio drops to 6 out of 10. Our analysis suggests that the improvement is due to better preservation of the cardiac signal morphology by the non-linear signal separation method. Hence, we expect that the non-linear signal separation method introduced in this paper will mostly benefit analysis methods investigating the cardiac radar signal morphology on a beat-to-beat basis

    Biomedical and Human Factors Requirements for a Manned Earth Orbiting Station

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    This report is the result of a study conducted by Republic Aviation Corporation in conjunction with Spacelabs, Inc.,in a team effort in which Republic Aviation Corporation was prime contractor. In order to determine the realistic engineering design requirements associated with the medical and human factors problems of a manned space station, an interdisciplinary team of personnel from the Research and Space Divisions was organized. This team included engineers, physicians, physiologists, psychologists, and physicists. Recognizing that the value of the study is dependent upon medical judgments as well as more quantifiable factors (such as design parameters) a group of highly qualified medical consultants participated in working sessions to determine which medical measurements are required to meet the objectives of the study. In addition, various Life Sciences personnel from NASA (Headquarters, Langley, MSC) participated in monthly review sessions. The organization, team members, consultants, and some of the part-time contributors are shown in Figure 1. This final report embodies contributions from all of these participants

    Aerospace medicine and biology: A continuing bibliography with indexes, supplement 164

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    This bibliography lists 275 reports, articles, and other documents introduced into the NASA scientific and technical information system in January 1977

    Heat stress and a countermeasure in the Shuttle rescueman's suit

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    Rescue of the astronaut flight crew from a contingency landing may risk exposure of the rescue crew to toxic propellants spilling from potentially ruptured tanks in the crew module area. An Aquala dry diver's suit has been in service by the rescue team to preclude exposure, especially in the water rescue scenario. Heat stress has become a factor of concern in recent years when older and less physically-fit team members work in this suit. Methods: Field testing was initiated using fully instrumented rescue men in a simulated scenario to determine the extent of heat stress. Two tests were accomplished, one in the normal (N) configuration and one with a proposed cooling countermeasure, the Steele vest (S). Results: Heat stress was high as indicated by average rectal temperatures (Tre) of 38.28 degrees C(100.9 degrees F) after the 45 minute protocol. Slopes of the regression equations describing the increase in Tre with time were greater (P less than 0.05) with N (0.073 plus or minus .008) compared to S (0.060 plus or minus .007). Projection of time to the 38.89 degree C (102 degree F) limit was increased by 15.3 percent with the vest. Mean skin temperature (Tsk) was higher (P less than 0.05) in N (38.33 plus or minus .11 degrees C) compared to S (34.33 plus or minus .39 degrees C). Average heart rate was higher (P less than 0.05 in N than S. Sweat loss, as measured by weight loss, was more (P less than 0.05) for N (1.09 plus or minus .09 kg versus 0.77 plus or minus .06 kg). Air usage, while slightly less for S, was not statistically different. Conclusion: The use of the cool vest provided significant relief from thermal stress in spite of the addition of 3.4 kg (7.5 pounds) weight and some loss in mobility

    Space Biology and Medicine

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    Volume IV is devoted to examining the medical and associated organizational measures used to maintain the health of space crews and to support their performance before, during, and after space flight. These measures, collectively known as the medical flight support system, are important contributors to the safety and success of space flight. The contributions of space hardware and the spacecraft environment to flight safety and mission success are covered in previous volumes of the Space Biology and Medicine series. In Volume IV, we address means of improving the reliability of people who are required to function in the unfamiliar environment of space flight as well as the importance of those who support the crew. Please note that the extensive collaboration between Russian and American teams for this volume of work resulted in a timeframe of publication longer than originally anticipated. Therefore, new research or insights may have emerged since the authors composed their chapters and references. This volume includes a list of authors' names and addresses should readers seek specifics on new information. At least three groups of factors act to perturb human physiological homeostasis during space flight. All have significant influence on health, psychological, and emotional status, tolerance, and work capacity. The first and most important of these factors is weightlessness, the most specific and radical change in the ambient environment; it causes a variety of functional and structural changes in human physiology. The second group of factors precludes the constraints associated with living in the sealed, confined environment of spacecraft. Although these factors are not unique to space flight, the limitations they entail in terms of an uncomfortable environment can diminish the well-being and performance of crewmembers in space. The third group of factors includes the occupational and social factors associated with the difficult, critical nature of the crewmembers' work: the risks involved in space flight, changes in circadian rhythms, and intragroup interactions. The physical and emotional stress and fatigue that develop under these conditions also can disturb human health and performance. In addition to these factors, the risk also exists that crewmembers will develop various illnesses during flight. The risk of illness is no less during space flight than on Earth, and may actually be greater for some classes of diseases

    Aerospace medicine and biology: A continuing bibliography with indexes (supplement 372)

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    This bibliography lists 208 reports, articles and other documents introduced into the NASA Scientific and Technical Information System during Jan. 1993. Subject coverage includes: aerospace medicine and physiology, life support systems and man/system technology, protective clothing, exobiology and extraterrestrial life, planetary biology, and flight crew behavior and performance

    Biotechnology to Combat COVID-19

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    This book provides an inclusive and comprehensive discussion of the transmission, science, biology, genome sequencing, diagnostics, and therapeutics of COVID-19. It also discusses public and government health measures and the roles of media as well as the impact of society on the ongoing efforts to combat the global pandemic. It addresses almost every topic that has been studied so far in the research on SARS-CoV-2 to gain insights into the fundamentals of the disease and mitigation strategies. This volume is a useful resource for virologists, epidemiologists, biologists, medical professionals, public health and government professionals, and all global citizens who have endured and battled against the pandemic

    New Insight into Brucella Infection and Foodborne Diseases

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    Brucellosis is an important zoonotic disease. More than half a million new cases from 100 countries are reported annually to the World Health Organization (WHO). The majority of patients are living in developing countries. Brucellosis is a systemic infection with a broad clinical spectrum, ranging from an asymptomatic disease to a severe and fatal illness. Clinical and laboratory features vary widely. The main presentations are acute febrile illness, localized infection, and chronic infection. Laboratory tools for diagnosis of brucellosis include culture, serology, and polymerase chain reaction (PCR). The goal of brucellosis therapy is to control the illness and prevent complications, relapses, and sequelae. Important principles of brucellosis treatment include use of antibiotics with activity in the acidic intracellular environment, use of combination regimens, and prolonged duration of treatment. This book is the result of several months of outstanding efforts by the authors and the revision of the content by experts in the field of brucellosis. This book is a valid resource and is intended for everyone interested in infectious disease to learn the most important aspects of brucellosis

    Loss of Signal: Aeromedical Lessons Learned from the STS-107 Columbia Space Shuttle Mishap

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    The editors of Loss of Signal wanted to document the aeromedical lessons learned from the Space Shuttle Columbia mishap. The book is intended to be an accurate and easily understood account of the entire process of recovering and analyzing the human remains, investigating and analyzing what happened to the crew, and using the resulting information to recommend ways to prevent mishaps and provide better protection to crewmembers. Our goal is to capture the passions of those who devoted their energies in responding to the Columbia mishap. We have reunited authors who were directly involved in each of these aspects. These authors tell the story of their efforts related to the Columbia mishap from their point of view. They give the reader an honest description of their responsibilities and share their challenges, their experiences, and their lessons learned on how to enhance crew safety and survival, and how to be prepared to support space mishap investigations. As a result of this approach, a few of the chapters have some redundancy of information and authors' opinions may differ. In no way did we or they intend to assign blame or criticize anyone's professional efforts. All those involved did their best to obtain the truth in the situations to which they were assigned
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