Search NASA⌕ Search

SEARCH · Search NASA

Results for “EAR”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1966

Histopathology of the Chimpanzee Ear

Four female and two male chimpanzees were secured in various positions on a Daisy Decelerator and subjected to forces ranging from 54 to 180 G. It was found that forces in excess of 54 G may rupture the tympanic membranes and cause subepithelial hemorrhages in the middle ear. The majority of cases showed proteinaceous material, with or without cells in the petrous air spaces. When exposed to forces above 119 G, there was engorgement and often rupture of the pericarotid venous plexus. When supine, distortion of both superior and posterior semicircular canals was found. With forces in excess of 54 G, the cupulae of the cristae ampullaris were either elevated or destroyed. The hair processes were also often broken off. The otolithic membranes, especially of the maculae utriculi were also elevated or otherwise distorted and the saccule was often partially collapsed. In several instances, there was an overabundance of a proteinaceous substance in the lumina of the vestibular apparatus and in the cochlear ducts with their associated scalae. In half the cases, the cochlear duct was narrowed by the depression of the vestibular membrane. Although there seems to be considerable individual variation in ability to withstand these forces, neither age, sex nor weight appear to directly influence the results. The possible sources for the materials found both in the air cells and labyrinth are discussed.

ACCELERATION TOLERANCE↗
NASA NTRS1980

Role of the middle ear muscle apparatus in mechanisms of speech signal discrimination

A method of impedance reflexometry was used to examine 101 students with hearing impairment in order to clarify the interrelation between speech discrimination and the state of the middle ear muscles. Ability to discriminate speech signals depends to some extent on the functional state of intraaural muscles. Speech discrimination was greatly impaired in the absence of stapedial muscle acoustic reflex, in the presence of low thresholds of stimulation and in very small values of reflex amplitude increase. Discrimination was not impeded in positive AR, high values of relative thresholds and normal increase of reflex amplitude in response to speech signals with augmenting intensity.

Moroz, B. S.↗
NASA NTRS1996

A Hydrodynamic Model of Transport in the Wheat Ear

The vascular arrangement in the main axis (rachis) of the wheat ear, studied and reported in a previous paper by the same, described a circuit-cascade system consisting of capacitance and resistance passages (so-called RC-circuits). Some hydromechanic aspects (e.g., resonance, impulse control) of this asymmetric transport system and their possible role and importance in the fluid supply are discussed. A theoretical analysis of how this system works, as well as samples of practical application are presented.

Stieber, Joseph↗
NASA NTRS1996

The Main Transport System in the Wheat Ear

The vascular system in the rachis, rachilla, and florets of the wheat ear was studied by direct microscopical observation of cleaned semi longitudinal sections. A periodic repetitive change of amphivasal and collateral phases was found along each main vascular bundle in the rachis. This change alternates between the two groups of main bundles and is related to the bilateral alternate arrangement of the spikelets on the rachis, so that a large amphivasal phase of the one group opposes the collateral phase of the other group. Ring-shaped tracheary inter-connections were observed mostly at the nodes. A similar system was found in the rachilla. There is a continuous uninterrupted tracheary connection between each of the florets and the rachis. A functional significance of the periodic changes observed has been suggested.

Stieber, Joseph↗
NASA NTRS1995

The glycan keratan sulfate in inner ear crystals

The otoconial matrix (OM) of chicks (Gallus domesticus) inner ear was analyzed. Histochemically the OM was reacted with phosphotungstic acid (PTA) and immunohistochemically with the monoclonal antibody antikeratan sulfate (antiKS). The OM was digested with the enzyme endo-beta-galactosidase (E beta Galase) or separated by 1D and 2D gel electrophoresis. PTA which reacts with glycoproteins precipitated the OM, suggesting that the OM contains glycoproteins. A central core in each crystal had no PTA staining, suggesting that the core lacked glycoproteins. Anti KS antibody stained the OM with increased density in older embryos as determined by color thresholding. E beta Galase, which cleaves the lactosamine repeating units in KS, decreased the immunostain by 30% in the OM and by 20% in the cartilage. The OM from the utricle, saccule and macula lagena contained similar molecular weight bands. Five dense bands in the OM were less dense in tissue and blood controls, suggesting that such bands are enriched in the OM. Isoelectric focusing of the OM showed a negatively charged high molecular weight smear not present in blood and faint in tissue controls. The high affinity of the OM for the cationic PTA stain, the strong immunohistochemical reaction of the OM with anti KS antibody and high molecular weight negative smear in 2D gels taken together suggest that: a) the OM contains large amounts of glycoproteins and glycans, one of which is keratan sulfate, because its immuno stain with antiKS antibody was decreased by the enzyme E beta Galase, b) the utricle, saccule and macula lagena may have similar composition, and c) the concentration of KS may increase gradually until complete mineralization of the OM is reached.

Non-NASA Center↗
NASA NTRS1982

Theoretical investigation of the force and dynamically coupled torsional-axial-lateral dynamic response of eared rotors

Difficulties in solution methodology to be used to deal with the potentially higher nonlinear rotor equations when dynamic coupling is included. A solution methodology is selected to solve the nonlinear differential equations. The selected method was verified to give good results even at large nonlinearity levels. The transfer matrix methodology is extended to the solution of nonlinear problems.

David, J. W.↗
NASA NTRS2002

Laboratory Studies of Extraterrestrial Ices and PAHs: Making an Astrobiological Silk Purse Out of An Interstellar Sow's Ear

Tremendous strides have been made in our understanding of interstellar material over the past twenty years thanks to significant, parallel developments in observational astronomy and laboratory astrophysics. Today, the composition of dust in the ISM is reasonably well constrained to cold, micron-sized particles of various refractory materials. Shrouded within the protective confines of cold, opaque molecular clouds--the birthplace of stars and planets--these particles secrete mantles of mixed molecular lees whose major components are also well constrained. Finally, amidst the molecular inventory of these ice mantles are likely to be found polycyclic aromatic hydrocarbons (PAHs), whose telltale infrared signature I is now recognized throughout the Universe. However, of what significance is this scenario to the origin of life in our solar system--or any other? The major components of the icy materials observed in interstellar clouds and in our own solar system are uniformly quite simple. In addition, despite the fact that PAHs likely represent the single largest molecular reservoir of organic carbon in evolving planetary systems, they are not what would be considered "biogenic" molecules. Although interesting from a chemical and astrophysical standpoint, in the absence of a mechanism by which these materials can be transformed into more biochemically significant structures, they are of little Astrobiological significance. In this talk, we will begin with a brief review of the nature and abundance of the "raw" population of PAHs and PAH-related materials in the ISM. From there, we will move on to explore our laboratory simulations of the photochemical evolution of realistic mixed molecular ices under conditions which simulate those encountered in the ISM and in evolving planetary systems. Particular attention will be paid to the surprisingly complex array of organic species that are produced in these ices from such a deceptively simple inventory of starting materials. In addition, we will explore the chemistry of PAHs under these conditions and consider its potential for transforming that rich repository of pre-biotic organic "ore" into materials of greater importance to Astrobiology.

Hudgins, Douglas M.↗
NASA NTRS2004

Analytical Bistatic k Space Images Compared to Experimental Swept Frequency EAR Images

A case study of flat plate scattering images obtained by the analytical bistatic k space and experimental swept frequency ISAR methods is presented. The key advantage of the bistatic k space image is that a single excitation is required, i.e., one frequency I one angle. This means that prediction approaches such as MOM only need to compute one solution at a single frequency. Bistatic image Fourier transform data are obtained by computing the scattered field at various bistatic positions about the body in k space. Experimental image Fourier transform data are obtained from the measured response to a bandwidth of frequencies over a target rotation range.

Shaeffer, John↗
NASA NTRS1998

Chicken (Gallus domesticus) inner ear afferents

Neurons from the vestibular (VG) and the statoacoustic (SAG) ganglion of the chick (Gallus domesticus) were evaluated histologically and morphometrically. Embryos at stages 34 (E8 days), 39 (E13 days) and 44 (E18 days) were sacrificed and temporal bones microdissected. Specimens were embedded in JB-4 methacrylate plastic, and stained with a mixture of 0.2% toluidine blue (TB) and 0.1% basic Fuschin in 25% ethanol or with a mixture of 2% TB and 1% paraphenylenediamine (PDA) for axon and myelin measurement study. Images of the VIIIth nerve were produced by a V150 (R) color imaging system and the contour of 200-300 neuronal bodies (perikarya) was traced directly on a video screen with a mouse in real time. The cross-sectional area of VG perikarya was 67.29 micrometers2 at stage 34 (E8), 128.46 micrometers2 at stage 39 (E13) and 275.85 micrometers2 at stage 44 (E18). The cross-sectional area of SAG perikarya was 62.44 micrometers2 at stage 34 (E8), 102.05 micrometers2 at stage 39 (E13) and 165.02 micrometers2 at stage 44 (E18). A significant cross-sectional area increase of the VG perikarya between stage 39 (E13) and stage 44 (E18) was determined. We randomly measured the cross-sectional area of myelin and axoplasm of hatchling afferent nerves, and found a correspondence between axoplasmic and myelin cross-sectional area in the utricular, saccular and semicircular canal nerve branches of the nerve. The results suggest that the period between stage 34 (E8) and 39 (E13) is a critical period for afferent neuronal development. Physiological and behavioral vestibular properties of developing and maturing hatchlings may change accordingly. The results compliment previous work by other investigators and provide valuable anatomical measures useful to correlate physiological data obtained from stimulation of the whole nerve or its parts.

NASA Discipline Neuroscience↗
NASA NTRS1997

Color threshold and ratio of S100 beta, MAP5, NF68/200, GABA & GAD. I. Distribution in inner ear afferents

Afferents of chick embryos (Gallus domesticus) VIIIth nerve were examined at E3, E6, E9, E13, El7, and hatching (NH) for anti-S100 beta, anti-MAP5, anti-GABA, anti-GAD and anti-NF68/200 stain. Different ages were processed together to determine if the distribution of these antibodies changed during synaptogenesis and myelination. Color thresholding showed that saturation of pixels changed for S100 beta only 5%, for NF68/200 10%, and for MAP5, 10%, between E9-NH. Color ratio of NF68/200 over MAP5 was 1.00 at E13 and 0.25 at E16 and NH. S100 beta, GABA and GAD were co-expressed on nerve endings at the edge of the maculae and center of the cristae, whereas hair cells in the center of the maculae expressed either S100 beta or GABA, but not both. S100 beta/NF68/200 shared antigenic sites on the chalices, but NF68/200 expression was higher than S100 beta in the chalices at hatching. MAP5 was expressed in more neurons than NF68/200 at E11, whereas NF68/200 was more abundant than MAP5 at hatching. The results suggest that: 1) the immunoexpression of these neuronal proteins is modulated concomitantly with the establishment of afferent synapses and myelination; 2) S100 beta may serve a neurotrophic function in the chalices where it is co-expressed with the neurotransmitter GABA and its synthesizing enzyme GAD.

NASA Discipline Neuroscience↗