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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
DOE OSTI2020

Combined computed tomography and position-resolved X-ray diffraction of an intact Roman-era Egyptian portrait mummy

Hawara Portrait Mummy 4, a Roman-era Egyptian portrait mummy, was studied with computed tomography (CT) and with CT-guided synchrotron X-ray diffraction mapping. These are the first X-ray diffraction results obtained non-invasively from objects within a mummy. The CT data showed human remains of a 5-year-old child, consistent with the female (but not the age) depicted on the portrait. Physical trauma was not evident in the skeleton. Diffraction at two different mummy-to-detector separations allowed volumetric mapping of features including wires and inclusions within the wrappings and the skull and femora. Additionally, the largest uncertainty in origin determination was approximately 1.5 mm along the X-ray beam direction, and diffraction- and CT-determined positions matched. Diffraction showed that the wires were a modern dual-phase steel and showed that the 7 × 5 × 3 mm inclusion ventral of the abdomen was calcite. Tracing the 00.2 and 00.4 carbonated apatite (bone's crystalline phase) reflections back to their origins produced cross-sectional maps of the skull and of femora; these maps agreed with transverse CT slices within approximately 1 mm. Coupling CT and position-resolved X-ray diffraction, therefore, offers considerable promise for non-invasive studies of mummies.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2023

Imaging Intact Filamentous Fungi from Spore to Hyphal Tip on the Nanoscale

Previously, the Pacific Northwest National Laboratory was limited by a 3-order of magnitude gap in resolution for direct 2-D and 3-D imaging of chemical, biological, energy and materials science systems. Our imaging instrumentation could directly visualize 3-D ultrastructure without labeling at resolutions less than 10-nanometers or greater than 10-micrometers. To address this gap, we procured and commissioned a Sigray NanoFast Bio-Lambda laboratory-based x-ray nanotomography system. This equipment provides the capability to image through tens of micrometers of organic materials at down to 35-nanometer resolution to bridge the nanoscale to the mesoscale for biological systems, organic polymers, environmental and particulate samples.

47 OTHER INSTRUMENTATION↗
DOE OSTI2018

Activation of intact bacteria and bacterial fragments mixed with agar as cloud droplets and ice crystals in cloud chamber experiments

Biological particles, including bacteria and bacterial fragments, have beenof much interest due to the special ability of some to nucleate ice atmodestly supercooled temperatures. This paper presents results from a recentstudy conducted on two strains of cultivated bacteria which suggest thatbacterial fragments mixed with agar, and not whole bacterial cells, serve ascloud condensation nuclei (CCN). Due to the absence of whole bacteria cellsin droplets, they are unable to serve as ice nucleating particles (INPs) inthe immersion mode under the experimental conditions. Experiments wereconducted at the Aerosol Interaction and Dynamics in the Atmosphere (AIDA)cloud chamber at the Karlsruhe Institute of Technology (KIT) by injectingbacteria-containing aerosol samples into the cloud chamber and inducing cloudformation by expansion over a temperature range of -5 to -12 ° C.Cloud droplets and ice crystals were sampled through a pumped counterflowvirtual impactor inlet (PCVI) and their residuals were characterized with asingle particle mass spectrometer (miniSPLAT). The size distribution of theoverall aerosol was bimodal, with a large particle mode composed of intactbacteria and a mode of smaller particles composed of bacterial fragmentsmixed with agar that were present in higher concentrations. Results fromthree expansions with two bacterial strains indicate that the cloud dropletresiduals had virtually the same size distribution as the smaller particlesize mode and had mass spectra that closely matched those of bacterialfragments mixed with agar. The characterization of ice residuals that weresampled through an ice-selecting PCVI (IS-PCVI) also shows that the sameparticles that activate to form cloud droplets, bacteria fragments mixed withagar, were the only particle type observed in ice residuals. These resultsindicate that the unavoidable presence of agar or other growth media inall laboratory studies conducted on cultivated bacteria can greatlyaffect the results and needs to be considered when interpreting CCN and INactivation data.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1961

Methods for Determining Blood Flow Through Intact Vessels of Experimental Animals Under Conditions of Gravitational Stress and in Extraterrestrial Space Capsules

Work during the initial six months of this program has proceeded along three lines: (1) technical development of blood flowmeter instrumentation: (2) surgical considerations related to special problems of chronic implantation of flowmeter probes: (3) study of the relationship between levels of blood flow and organ activity. Principal engineering effort has been focused on the fundamental phenomena operative in the flowmeter probe and on probe design. Two probes have been constructed and a third is nearing completion. A previously unrecognized source of zero drift has been discovered and corrected. has been designed, assembled, tested and successfully employed in work on the several probes. A significant innovation which has been introduced is the use of a transformer coupled input for suppression of unwanted common mode signals. New low noise transistor amplifiers with characteristics suitable for space vehicle packaging are being developed. Linearity of the present apparatus has been found to extend at least into the near turbulent flow region. Attention has been directed to the two vascular beds of physiologic interest that present particular problems with regard to chronic implantation of flowmeter probes, the myocardium and the liver. Surgical techniques have been perfected that will permit myocardial and liver blood flow measurement. Two groups of animals have successfully undergone surgery and await the implantation of probes. Studies of the relationship between organ blood flow and levels of physiologic activity have been initiated. The first organ system studied was the heart, For the first time autoregulatory mechanisms have been demonstrated within the myocardial vascular bed which rapidly and precisely maintain coronary blood flow at a level i n keeping with the magnitude of cardiac work, Following a summary statement of the status of the program, the work performed is described, A financial review of expenditures incurred and a proposal for future funding are appended,

Shaw, R. F.↗
NASA NTRS1975

Elastic modulus of the human intact left ventricle - Determination and physiological interpretation

The left ventricle (l.v.) is represented as a shell of muscle whose performance is characterized in terms of the chamber pressure and stress/strain in the ventricular wall; the effective elastic modulus of the l.v. relates these performance variables, and hence represents the transfer function of the left ventricular physiological system. A method is presented for indirectly determining the effective modulus E for the left ventricle. The method employs a thick-walled mathematical model of the l.v. having a homogeneous isotropic medium. Instantaneous values of E are determined for subjects with heart diseases of varied etiologies, in order to assess the responses of the l.v. to chronic overloads of pressure and volume. Resulting values for E are used diagnostically to characterize the physiological state of the l.v. Normal values of E, at systole, indicate that the strength of contraction exercised by the l.v. is normal, and hence is an indication of the l.v. having adjusted to the heart disease.

Ghista, D. N.↗
NASA NTRS1983

Measurement and Control of Free Calcium Inside Small Intact Cells

The use of dye to measure intracellular free calcium concentration was discussed. Difficulty in measuring the calcium is caused by two problems: the small amount of calcium available for testing, and the selectivity to bind calcium at 100 nanomolar excludes substances from entering the cell.

Tsien, R. Y.↗
NASA NTRS1986

Nitrogen uptake and utilization by intact plants

The results of experiments support the proposed conceptual model that relates nitrogen uptake activity by plants as a balanced interdependence between the carbon-supplying function of the shoot and the nitrogen-supplying function of the roots. The data are being used to modify a dynamic simulation of plant growth, which presently describes carbon flows through the plant, to describe nitrogen uptake and assimilation within the plant system. Although several models have been proposed to predict nitrogen uptake and partitioning, they emphasize root characteristics affecting nutrient uptake and relay on empirical methods to describe the relationship between nitrogen and carbon flows within the plant. Researchers, on the other hand, propose to continue to attempt a mechanistic solution in which the effects of environment on nitrogen (as well as carbon) assimilation are incorporated through their direct effects on photosynthesis, respiration, and aging processes.

Raper, C. D., Jr.↗
NASA NTRS1988

Collecting Hypervelocity Particles Intact

Experiments conducted to develop targets capturing micrometerorites, dust, and other small particles in outer space traveling at speed of several kilometers per second. Principal criterion for such target; must stop particles while preserving mineralogical properties for subsequent analysis. Collection concept simple: foam or other underdense medium used to remove kinetic energy gently from impinging particle. Well-designed collector decelerates and stops particle without imposing stresses beyond critical stresses that damage particle thermally or mechanically. Target technology also useful in terrestrial studies of debris for explosions.

Tsou, Peter↗
NASA NTRS1989

Metabolism of branched-chain amino acids in leg muscles from tail-cast suspended intact and adrenalectomized rats

The effects of muscle unloading, adrenalectomy, and cortisol treatment on the metabolism of branched-chain amino acids in the soleus and extensor digitorum longus of tail-cast suspended rats were investigated using C-14-labeled lucine, isoleucine, and valine in incubation studies. It was found that, compared to not suspended controls, the degradation of branched-chain amino acids in hind limb muscles was accelerated in tail-cast suspended rats. Adrenalectomy was found to abolish the aminotransferase flux and to diminish the dehydrogenase flux in the soleus. The data also suggest that cortisol treatment increases the rate of metabolism of branched-chain amino acids at the dehydrogenase step.

Jaspers, Stephen R.↗