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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1999

Multimode-Optical-Fiber Imaging Probe

Currently, endoscopic surgery uses single-mode fiber-bundles to obtain in vivo image information inside the orifices of the body. This limits their use to the larger natural orifices and to surgical procedures where there is plenty of room for manipulation. The knee joint, for example, can be easily viewed with a fiber optic viewer, but joints in the finger cannot. However, there are a host of smaller orifices where fiber endoscopy would play an important role if a cost effective fiber probe were developed with small enough dimensions (less than or equal to 250 microns). Examples of beneficiaries of micro-endoscopes are the treatment of the Eustatian tube of the middle ear, the breast ducts, tear ducts, coronary arteries, fallopian tubes, as well as the treatment of salivary duct parotid disease, and the neuro endoscopy of the ventricles and spinal canal. This work describes an approach for recovering images from tightly confined spaces using multimode. The concept draws upon earlier works that concentrated on image recovery after two-way transmission through a multimode fiber as well as work that demonstrated the recovery of images after one-way transmission through a multimode fiber. Both relied on generating a phase conjugated wavefront, which was predistorted with the characteristics of the fiber. The approach described here also relies on generating a phase conjugated wavefront, but utilizes two fibers to capture the image at some intermediate point (accessible by the fibers, but which is otherwise visually inaccessible).

Jackson, Deborah↗
NASA NTRS2000

Multimode-Optical-Fiber Imaging Probe

Currently, endoscopic surgery uses single-mode fiber-bundles to obtain in vivo image information inside orifices of the body. This limits their use to the larger natural bodily orifices and to surgical procedures where there is plenty of room for manipulation. The knee joint, for example can be easily viewed with a fiber optic viewer, but joints in the finger cannot. However, there are a host of smaller orifices where fiber endoscopy would play an important role if a cost effective fiber probe were developed with small enough dimensions (< 250 microns). Examples of beneficiaries of micro-endoscopes are the treatment of the Eustatian tube of the middle ear, the breast ducts, tear ducts, coronary arteries, fallopian tubes, as well as the treatment of salivary duct parotid disease, and the neuro endoscopy of the ventricles and spinal canal. To solve this problem, this work describes an approach for recovering images from. tightly confined spaces using multimode fibers and analytically demonstrates that the concept is sound. The proof of concept draws upon earlier works that concentrated on image recovery after two-way transmission through a multimode fiber as well as work that demonstrated the recovery of images after one-way transmission through a multimode fiber. Both relied on generating a phase conjugated wavefront which was predistorted with the characteristics of the fiber. The described approach also relies on generating a phase conjugated wavefront, but utilizes two fibers to capture the image at some intermediate point (accessible by the fibers, but which is otherwise visually unaccessible).

Jackson, Deborah↗
DOE OSTI2021

The Importance of Radiation Dose to the Atherosclerotic Plaque in the Left Anterior Descending Coronary Artery for Radiation-Induced Cardiac Toxicity of Breast Cancer Patients?

Radiation-induced acute coronary events (ACEs) may occur as a treatment-related late adverse effect of breast cancer (BC) radiation. However, the underlying mechanisms behind this radiation-induced cardiac disease remain to be determined. The objective of this study was to test the hypothesis that radiation dose to calcified atherosclerotic plaques in the left anterior descending coronary artery (LAD) is a better predictor for ACEs than radiation dose to the whole heart or left ventricle in patients with BC treated with radiation therapy.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
NASA NTRS1976

Arteriosclerosis Detection

The Veterans Administration Hospital used computer image-processing techniques to detect arteriosclerosis. Originally developed by Goddard Space Flight Center engineers to enhance spacecraft pictures, this device replaced the previous testing for this disease which was extremely painful and time consuming. With this instrument, computer detected edges are shown along with an estimate of location of pre-arteriosclerosis vessel wall. The difference between the two represents the relative amount of disease in the blood vessel. Instrumentation will be expanded again in 1976 to analyze the coronary arteries and the blood vessels of the retina.

Source record↗
DOE OSTI2021

Quantile-dependent expressivity of serum C-reactive protein concentrations in family sets

“Quantile-dependent expressivity” occurs when the effect size of a genetic variant depends upon whether the phenotype (e.g., C-reactive protein, CRP) is high or low relative to its distribution. We have previously shown that the heritabilities ( h 2 ) of coffee and alcohol consumption, postprandial lipemia, lipoproteins, leptin, adiponectin, adiposity, and pulmonary function are quantile-specific. Whether CRP heritability is quantile-specific is currently unknown. Methods Serum CRP concentrations from 2,036 sibships and 6,144 offspring-parent pairs were analyzed from the Framingham Heart Study. Quantile-specific heritability from full-sib (β FS , h 2 ={(1 + 8r spouse β FS ) 0.5 - 1}/(2r spouse )) and offspring-parent regression slopes (β OP , h 2 = 2β OP /(1 + r spouse )) were estimated robustly by quantile regression with nonparametric significance determined from 1,000 bootstrap samples. Results Quantile-specific h 2 (±SE) increased with increasing percentiles of the offspring’s age- and sex-adjusted CRP distribution when estimated from β OP ( P trend = 0.0004): 0.02 ± 0.01 at the 10th, 0.04 ± 0.01 at the 25th, 0.10 ± 0.02 at the 50th, 0.20 ± 0.05 at the 75th, and 0.33 ± 0.10 at the 90th percentile, and when estimated from β FS ( P trend = 0.0008): 0.03±0.01 at the 10th, 0.06 ± 0.02 at the 25th, 0.14 ± 0.03 at the 50th, 0.24 ± 0.05 at the 75th, and 0.53 ± 0.21 at the 90th percentile. Conclusion Heritability of serum CRP concentration is quantile-specific, which may explain or contribute to the inflated CRP differences between CRP (rs1130864, rs1205, rs1800947, rs2794521, rs3091244), FGB (rs1800787), IL-6 (rs1800795, rs1800796), IL6R (rs8192284), TNF- α (rs1800629) and APOE genotypes following CABG surgery, stroke, TIA, curative esophagectomy, intensive periodontal therapy, or acute exercise; during acute coronary syndrome or Staphylococcus aureus bacteremia; or in patients with chronic rheumatoid arthritis, diabetes, peripheral arterial disease, ankylosing spondylitis, obesity or inflammatory bowel disease or who smoke.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS2018

Cardiovascular Disease Outcomes Among the NASA Astronaut Corps

BACKGROUND: Acute effects of spaceflight on the cardiovascular system have been studied extensively, but the combined chronic effects of spaceflight and aging are not well understood. Preparation for and participation in spaceflight activities are associated with changes in the cardiovascular system such as decreased carotid artery distensibility and decreased ventricular mass which may lead to an increased risk of cardiovascular disease. Additionally, astronauts who travel into space multiple times or for longer durations may be at an increased risk across their lifespan. To that end, the purpose of this study was to determine the incidence of common cardiovascular disease (CVD) outcomes among the NASA astronaut corps during their active career and through retirement. METHODS: Cardiovascular disease outcomes were defined as reports of any of the following: myocardial infarction (MI), revascularization procedures (coronary artery bypass graft surgery [CABG] or percutaneous coronary intervention [PCI]), hypertension, stroke or transient ischemic attack [TIA], heart failure, or total CVD (as defined by the AHA - combined outcome of MI, Angina Pectoris, heart failure, stroke, and hypertension). Each outcome was identified individually from review of NASA's Electronic Medical Record (EMR), EKG reports, and death certificates using ICD-9 codes as well as string searches of physician notes of astronaut exams that occurred between 1959 and 2016. RESULTS: Of 338 NASA astronauts selected as of 2016, 9 reported an MI, 12 reported a revascularization procedure, (7 PCI and 5 CABG), 4 reported Angina (without MI), 5 reported heart failure, 9 reported stroke/TIA, and 96 reported hypertension. Total CVD was reported in 105 astronauts. No astronaut who had an MI or revascularization procedure flew a spaceflight mission following the event. All MI, revascularization, and stroke events occurred in male astronauts. When reviewing astronaut ECG reports, abnormal ECG reports were found in only 8% of records (n=430) and mainly among retired astronauts (82%), with marked sinus bradycardia being the reason for the abnormal classification.

Charvat, Jacqueline M.↗
NASA NTRS2003

Bone morphogenic protein 4 produced in endothelial cells by oscillatory shear stress stimulates an inflammatory response

Atherosclerosis is now viewed as an inflammatory disease occurring preferentially in arterial regions exposed to disturbed flow conditions, including oscillatory shear stress (OS), in branched arteries. In contrast, the arterial regions exposed to laminar shear (LS) are relatively lesion-free. The mechanisms underlying the opposite effects of OS and LS on the inflammatory and atherogenic processes are not clearly understood. Here, through DNA microarrays, protein expression, and functional studies, we identify bone morphogenic protein 4 (BMP4) as a mechanosensitive and pro-inflammatory gene product. Exposing endothelial cells to OS increased BMP4 protein expression, whereas LS decreased it. In addition, we found BMP4 expression only in the selective patches of endothelial cells overlying foam cell lesions in human coronary arteries. The same endothelial patches also expressed higher levels of intercellular cell adhesion molecule-1 (ICAM-1) protein compared with those of non-diseased areas. Functionally, we show that OS and BMP4 induced ICAM-1 expression and monocyte adhesion by a NFkappaB-dependent mechanism. We suggest that BMP4 is a mechanosensitive, inflammatory factor playing a critical role in early steps of atherogenesis in the lesion-prone areas.

NASA Program Fundamental Space Biology↗
NASA NTRS2010

Mapping and Quantification of Vascular Branching in Plants, Animals and Humans by VESGEN Software

Humans face daunting challenges in the successful exploration and colonization of space, including adverse alterations in gravity and radiation. The Earth-determined biology of humans, animals and plants is significantly modified in such extraterrestrial environments. One physiological requirement shared by humans with larger plants and animals is a complex, highly branching vascular system that is dynamically responsive to cellular metabolism, immunological protection and specialized cellular/tissue function. The VESsel GENeration (VESGEN) Analysis has been developed as a mature beta version, pre-release research software for mapping and quantification of the fractal-based complexity of vascular branching. Alterations in vascular branching pattern can provide informative read-outs of altered vascular regulation. Originally developed for biomedical applications in angiogenesis, VESGEN 2D has provided novel insights into the cytokine, transgenic and therapeutic regulation of angiogenesis, lymphangiogenesis and other microvascular remodeling phenomena. Vascular trees, networks and tree-network composites are mapped and quantified. Applications include disease progression from clinical ophthalmic images of the human retina; experimental regulation of vascular remodeling in the mouse retina; avian and mouse coronary vasculature, and other experimental models in vivo. We envision that altered branching in the leaves of plants studied on ISS such as Arabidopsis thaliana cans also be analyzed.

Parsons-Wingerter, Patricia A.↗
NASA NTRS2010

Mapping and Quantification of Vascular Branching in Plants, Animals and Humans by VESGEN Software

Humans face daunting challenges in the successful exploration and colonization of space, including adverse alterations in gravity and radiation. The Earth-determined biology of plants, animals and humans is significantly modified in such extraterrestrial environments. One physiological requirement shared by larger plants and animals with humans is a complex, highly branching vascular system that is dynamically responsive to cellular metabolism, immunological protection and specialized cellular/tissue function. VESsel GENeration (VESGEN) Analysis has been developed as a mature beta version, pre-release research software for mapping and quantification of the fractal-based complexity of vascular branching. Alterations in vascular branching pattern can provide informative read-outs of altered vascular regulation. Originally developed for biomedical applications in angiogenesis, VESGEN 2D has provided novel insights into the cytokine, transgenic and therapeutic regulation of angiogenesis, lymphangiogenesis and other microvascular remodeling phenomena. Vascular trees, networks and tree-network composites are mapped and quantified. Applications include disease progression from clinical ophthalmic images of the human retina; experimental regulation of vascular remodeling in the mouse retina; avian and mouse coronary vasculature, and other experimental models in vivo. We envision that altered branching in the leaves of plants studied on ISS such as Arabidopsis thaliana cans also be analyzed.

Parsons-Wingerter, P. A.↗
NASA NTRS1988

Earth benefits from space life sciences

The applications to medicine of various results from space exploration are examined. Improvements have been made in the management of cardiovascular disease, in particular the use of the ultrasonic scanner to image arteries in three dimensions, the use of excimer lasers to disrupt arterial plaques in coronary blood vessels, and the use of advanced electrodes for cardiac monitoring. A bone stiffness analyzer has helped to diagnose osteoporosis and aid in its treatment. An automated light microscope system is used for chromosome analysis, and an X-ray image intensifier called Lixiscope is used in emergency medical care. An advanced portable defibrillator has been developed for the heart, and an insulin delivery system has been derived from space microminiaturization techniques.

Garshnek, V.↗
NASA NTRS1970

The Value of Continued Followup in a Preventive Medicine Program

Continued monitoring of hypertension and cholesterol levels in NASA employees by regularly scheduled medical examinations prevents an increase in employee disability and cardiovascular mortality rates. Adequate therapeutic control for younger hypertensive employees is demonstrated by records on mortality and heart diseases over a period of 28 months. It confirmed the importance of systolic blood pressure as diagnostic tool for the inherent risk factor. The prevalence of additional coronary risk factors among employees with hypercholesterolemia is considerably less than in employees with hypertension.

Villafana, C.↗
NASA NTRS1988

Serotonin, atherosclerosis, and collateral vessel spasm

Studies on animal models demonstrate that platelet products contribute to vascular spasm in ischemic syndromes and that this is reversible with administration of ketanserin and thromboxane synthesis inhibitors. Laboratory animals (dogs, rabbits, and rats) that had femoral artery ligations exhibited supersensitivity to serotonin within days in their collateral blood vessels. This supersensitivity lasted at least 6 months. The response to serotonin was reversed by ketanserin, but not by 5HT-1 antagonists. Supersensitivity does not extend to norepinephrine, and alpha blockers do not influence the response to serotonin. It appears that platelet activation by endothelial injury contributes to ischemia through blood vessel occlusion and vascular spasm. When platelet activation occurs in vivo, blood vessel occlusion and vascular spasm are reversible in part by using ketanserin or agents that block thromboxane synthesis or its action. Combining both classes of agents reverses spasm completely. These findings support existing evidence that platelet products contribute to vascular disease, and provide an approach to improved management with currently available pharmacologic agents.

Review, Tutorial↗
NASA NTRS1992

Comparison of computer- and human-derived coronary angiographic end-point measures for controlled therapy trials

The Cholesterol Lowering Atherosclerosis Study, a randomized angiographic clinical trial, demonstrated the beneficial effect of niacin/colestipol plus diet therapy on coronary atherosclerosis. Outcome was determined by panel-based estimates (viewed in both still and cine modes) of percent stenosis severity and change in native artery and bypass graft lesions. Computer-based quantitative coronary angiography (QCA) was also used to measure lesion and bypass graft stenosis severity and change in individual frames closely matched in orientation, opacification, and cardiac phase. Both methods jointly evaluated 350 nonoccluded lesions. The correlation between QCA and panel estimates of lesion size was 0.70 (p less than 0.0001) and for change in lesion size was 0.28 (p = 0.002). Agreement between the two methods in classifying lesion changes (i.e., regression, unchanged, or progression) occurred for 60% (210 of 350) of the lesions kappa +/- SEM = 0.20 +/- 0.05, p less than 0.001). The panel identified 442 nonoccluded lesions for which QCA stenosis measurements could not be obtained. Lesions not measurable by QCA included those with stenosis greater than 85% that could not be reliably edge tracked, segments with diffuse or ecstatic disease that had no reliable reference diameter, and segments for which matched frames could not be located. Seventy-nine lesions, the majority between 21% and 40% stenosis, were identified and measured by QCA but were not identified by the panel. This comparison study demonstrates the need to consider available angiographic measurement methods in relation to the goals of their use.

NASA Center JPL↗
NASA NTRS1970

Normally Expected Aberrations in the 8-hour Dynamic EKG

The establishment of norms for interpreting long term dynamic electrocardiograms is attempted by correlating a completely disease symptom and cardiac risk factor free sample with a non-pure sample in the direction of normality on various variables. Out of a population of 362 subjects exposed to dynamic electrocardiogram testing, a discrimination between normals and abnormals in terms of traditional risk factors was observed. The two groups differed significantly on the following variables: cholesterol, smoking, systolic blood pressure, white blood count, fasting blood sugar, uric acid, resting EKG, year of birth, and coronary insufficiency.

Fleck, R. L.↗
NASA NTRS2012

New Therapeutic Window of Regenerative Opportunity in Diabetic Retinopathy by VESGEN Analysis

Vascular pattern may serve as a useful new biomarker principle of complex, multi-scale signaling in pathological, physiological angiogenesis and microvascular remodeling. Each angiogenesis stimulator or inhibitor we have analyzed, including VEGF, bFGF, TGF-beta1, angiostatin and triamcinolone acetonide, has induced a novel "fingerprint" or "signature" biomarker vascular pattern that is spatio-temporally unique. Remodeling vasculature thereby provides an informative read-out of dominant molecular signaling, when analyzed by innovative, fractal-based VESsel GENeration (VESGEN) Analysis software. Using VESGEN to analyze ophthalmic clinical vascular images, we recently introduced a potential paradigm shift to the understanding of early-stage progression that suggests new regenerative opportunities for human diabetic retinopathy (DR), the major blinding disease for working-aged adults. In a pilot study, we discovered that angiogenesis oscillates as a surprising, homeostatic-like regeneration of retinal vessels during early progression of DR (IOVS 51(1):498). Results suggest that the term non-proliferative DR may be a misnomer. In new studies, normalization of the vasculature will be determined from the response of vascular pattern to therapeutic monitoring and treatment. We have mapped and quantified in vivo experimental models of angiogenesis, lymphangiogenesis and intravital blood flow from cellular/molecular to higher systems levels that include a murine model of infant retinopathy of prematurity (ROP); developing and pathological coronary and placental-like vessel models; progressive intestinal inflammation, growing murine tumors, and other pathological, physiological and therapeutically treated tissues of transgenic mice and avian embryos. Vascular Alterations, Visual Impairments (VIIP) & Increased Intracranial Pressure (ICP), Immunosuppression & Bone Loss: NASA-defined risk categories for human space exploration and ISS Utilization

Parsons-Wingert, Patricia A.↗
NASA NTRS2000

Color M-mode Doppler flow propagation velocity is a preload insensitive index of left ventricular relaxation: animal and human validation

OBJECTIVES: To determine the effect of preload in color M-mode Doppler flow propagation velocity (v(p)). BACKGROUND: The interpretation of Doppler filling patterns is limited by confounding effects of left ventricular (LV) relaxation and preload. Color M-mode v(p) has been proposed as a new index of LV relaxation. METHODS: We studied four dogs before and during inferior caval (IVC) occlusion at five different inotropic stages and 14 patients before and during partial cardiopulmonary bypass. Left ventricular (LV) end-diastolic volumes (LV-EDV), the time constant of isovolumic relaxation (tau), left atrial (LA) pre-A and LV end-diastolic pressures (LV-EDP) were measured. Peak velocity during early filling (E) and v(p) were extracted by digital analysis of color M-mode Doppler images. RESULTS: In both animals and humans, LV-EDV and LV-EDP decreased significantly from baseline to IVC occlusion (both p < 0.001). Peak early filling (E) velocity decreased in animals from 56 +/- 21 to 42 +/- 17 cm/s (p < 0.001) without change in v(p) (from 35 +/- 15 to 35 +/- 16, p = 0.99). Results were similar in humans (from 69 +/- 15 to 53 +/- 22 cm/s, p < 0.001, and 37 +/- 12 to 34 +/- 16, p = 0.30). In both species, there was a strong correlation between LV relaxation (tau) and v(p) (r = 0.78, p < 0.001, r = 0.86, p < 0.001). CONCLUSIONS: Our results indicate that color M-mode Doppler v(p) is not affected by preload alterations and confirms that LV relaxation is its main physiologic determinant in both animals during varying lusitropic conditions and in humans with heart disease.

Non-NASA Center↗
NASA NTRS1992

A new technique for simultaneous monitoring of electrocardiogram and walking cadence

A new technique for simultaneously recording continuous electrocardiographic (ECG) data and walking step rate (cadence) is described. The ECG and gait signals are recorded on 2 channels of an ambulatory Holter monitor. Footfall is detected using ultrathin, force-sensitive foot switches and is frequency modulated. The footfall signal provides an indication of the subject's activity (walking or standing), as well as the instantaneous walking rate. Twenty-three young and elderly subjects were studied to demonstrate the use of this ECG and gait recorder. High-quality gait signals were obtained in all subjects, and the effects of walking on the electrocardiogram were assessed. Initial investigation revealed the following findings: (1) Although walking rates were similar in young and elderly subjects, the elderly had both decreased heart rate (HR) variability (p < 0.005) and increased cadence variability (p < 0.0001). (2) Overall, there was an inverse relation between HR and cadence variability (r = -0.73). Three elderly subjects with no known cardiac disease had HR and cadence variability similar to those of the young, whereas elderly subjects with history of congestive heart failure were among those with the lowest HR variability and the highest cadence variability. (3) Low-frequency (approximately equal to 0.1 Hz) HR oscillations (frequently observed during standing) persisted during walking in all young subjects. (4) In some subjects, both step rate and HR oscillated at the same low frequency (approximately equal to 0.1 Hz) previously identified with autonomic control of the baroreflex.(ABSTRACT TRUNCATED AT 250 WORDS).

NASA Discipline Cardiopulmonary↗
NASA NTRS2002

Left ventricular outflow tract mean systolic acceleration as a surrogate for the slope of the left ventricular end-systolic pressure-volume relationship

OBJECTIVE: The goal of this study was to analyze left ventricular outflow tract systolic acceleration (LVOT(Acc)) during alterations in left ventricular (LV) contractility and LV filling. BACKGROUND: Most indexes described to quantify LV systolic function, such as LV ejection fraction and cardiac output, are dependent on loading conditions. METHODS: In 18 sheep (4 normal, 6 with aortic regurgitation, and 8 with old myocardial infarction), blood flow velocities through the LVOT were recorded using conventional pulsed Doppler. The LVOT(Acc) was calculated as the aortic peak velocity divided by the time to peak flow; LVOT(Acc) was compared with LV maximal elastance (E(m)) acquired by conductance catheter under different loading conditions, including volume and pressure overload during an acute coronary occlusion (n = 10). In addition, a clinically validated lumped-parameter numerical model of the cardiovascular system was used to support our findings. RESULTS: Left ventricular E(m) and LVOT(Acc) decreased during ischemia (1.67 +/- 0.67 mm Hg.ml(-1) before vs. 0.93 +/- 0.41 mm Hg.ml(-1) during acute coronary occlusion [p < 0.05] and 7.9 +/- 3.1 m.s(-2) before vs. 4.4 +/- 1.0 m.s(-2) during coronary occlusion [p < 0.05], respectively). Left ventricular outflow tract systolic acceleration showed a strong linear correlation with LV E(m) (y = 3.84x + 1.87, r = 0.85, p < 0.001). Similar findings were obtained with the numerical modeling, which demonstrated a strong correlation between predicted and actual LV E(m) (predicted = 0.98 [actual] -0.01, r = 0.86). By analysis of variance, there was no statistically significant difference in LVOT(Acc) under different loading conditions. CONCLUSIONS: For a variety of hemodynamic conditions, LVOT(Acc) was linearly related to the LV contractility index LV E(m) and was independent of loading conditions. These findings were consistent with numerical modeling. Thus, this Doppler index may serve as a good noninvasive index of LV contractility.

Non-NASA Center↗