ALBERT

Description: The development and maturation of the endolymphatic sac (ES) and duct (ED) were studied in the newt Cynops pyrrhogaster. The ES first appears as an oval capsule at the dorsal-medial tip of the otic vesicle at stage 39, about 11 days after oviposition. The ES consists of polymorphous epithelial cells with a minimum of cytoplasm. The intercellular space (IS) between the epithelial cells is narrow and has a smooth surface. At stage 44, the size of the ES increases as many vacuoles in the IS become filled. At stage 46, 18 days after oviposition, the ES elongates markedly and a slit-like lumen is found in the ES. The epithelium contains a few cell organelles which are scattered in the cytoplasm. The vacuoles in the IS are fused, which expands the IS. Two days later (stage 48), floccular material (endolymph) is present in the expanded lumen. The IS dilates and has a wide and irregular appearance. At stage 50, approximately 26 days after oviposition, the ES extends and expands significantly and crystals (otoconia) can now be seen in the widened lumen of the ES. The cytoplasm of the cuboidal epithelial cells contains an abundance of vesicles surrounded by ribosomes and Golgi complexes. Intercellular digitations are formed in the expanded IS. At stage 54, the ES forms a large bellow-like pouch. Numerous otoconia accumulate in the lumen. Free floating cells and cell debris can be seen in the lumen at this stage. The epithelial cells contain numerous cytoplasmic organelles which are evenly distributed in the cytoplasm. Granules are found in the apical and lateral cytoplasm. The IS is loose and displays a labyrinthine appearance. The primitive ED first appears as a connection between the ES and the saccule but no lumen is present inside at stage 39. At stage 46, a narrow lumen is formed in the ED, which corresponds to the formation of the ES lumen. At stage 50, as the ED extends, floccular material is seen in the lumen. At stage 54, the ED bears numerous microvilli on its luminal surface. Otoconia and endolymph are present in the ED. Tight junctions between the epithelial cells are formed at stage 46. A fully developed intercellular junctional complex is produced at stage 54. Based on the development of the ES and ED, the maturation of function of the ES and ED are discussed.

Description: The Structural Assembly and Demonstration Experiment (SADE) demonstrates that the Shuttle is a suitable base for space construction; this includes a test of the Shuttle's control system to determine its performance when a long attached truss or beam is extended from the bay. Examples of Shuttle-related systems that will receive special attention are the RMS, the lighting system, and the crew assembly capabilities. A second purpose is to determine the extent to which the assembly results from the Neutral Buoyancy Simulator can be used to forecast the results of space assembly is determined. Finally, the SADE truss design will be validated by measuring the performance of the deployment, the special connectors, and the assembly methods.

Description: The design requirements for three major space platform systems are identified. The three were the Science and Applications Space Platform (SASP), the Geostationary Platform (GSP), and the Satellite Power System (SPS). Because the SASP and GSP were assumed to require no advanced technology for their development an advanced version of each was selected on which to base the design requirements. The SPS represented the opposite development state hence a nearer term test article was selected on which to base the requirements. The development period for these missions is estimated.

Description: To better understand the mechanisms that could modulate the formation of otoconia, calcium carbonate granules in the inner ear of vertebrate species, we examined statoconia formation in the gravity-sensing organ, the statocyst, of the gastropod mollusk Aplysia californica using an in vitro organ culture model. We determined the type of calcium carbonate present in the statoconia and investigated the role of carbonic anhydrase (CA) and urease in regulating statocyst pH as well as the role of protein synthesis and urease in statoconia production and homeostasis in vitro. The type of mineral present in statoconia was found to be aragonitic calcium carbonate. When the CA inhibitor, acetazolamide (AZ), was added to cultures of statocysts, the pH initially (30 min) increased and then decreased. The urease inhibitor, acetohydroxamic acid (AHA), decreased statocyst pH. Simultaneous addition of AZ and AHA caused a decrease in pH. Inhibition of urease activity also reduced total statoconia number, but had no effect on statoconia volume. Inhibition of protein synthesis reduced statoconia production and increased statoconia volume. In a previous study, inhibition of CA was shown to decrease statoconia production. Taken together, these data show that urease and CA play a role in regulating statocyst pH and the formation and maintenance of statoconia. CA produces carbonate ion for calcium carbonate formation and urease neutralizes the acid formed due to CA action, by production of ammonia.

Description: While many of the characteristics of the cosmic unidentified infrared (UIR) emission bands observed for interstellar and circumstellar sources within the Milky Way and other galaxies, can be best attributed to vibrational modes of the variants of the molecular family known as polycyclic aromatic hydrocarbons (PAH), there are open questions that need to be resolved. Among them is the observed strength of the 6.2 micron (1600 cm(-1)) band relative to other strong bands, and the generally low strength for measurements in the laboratory of the 1600 cm(-1) skeletal vibration band of many specific neutral PAH molecules. Also, experiments involving laser excitation of some gas phase neutral PAH species while producing long lifetime state emission in the 3.3 micron (3000 cm(-1)) spectral region, do not result in significant 6.2 micron (1600 cm(-1)) emission. A potentially important variant of the neutral PAH species, namely hydrogenated-PAH (H(N)-PAH) which exhibit intriguing spectral correlation with interstellar and circumstellar infrared emission and the 2175 A extinction feature, may be a factor affecting the strength of 6.2 micron emission. These species are hybrids of aromatic and cycloalkane structures. Laboratory infrared absorption spectroscopy augmented by density function theory (DFT) computations of selected partially hydrogenated-PAH molecules, demonstrates enhanced 6.2 micron (1600 cm(-1)) region skeletal vibration mode strength for these molecules relative to the normal PAH form. This along with other factors such as ionization or the incorporation of nitrogen or oxygen atoms could be a reason for the strength of the cosmic 6.2 micron (1600 cm(-1)) feature.

Description: Single-photon infrared emission spectroscopy (SPIRES) has been used to measure emission spectra from polycyclic aromatic hydrocarbons (PAHs). A supersonic free-jet expansion has been used to provide emission spectra of rotationally cold and vibrationally excited naphthalene and benzene. Under these conditions, the observed width of the 3.3-micrometers (C-H stretch) band resembles the bandwidths observed in experiments in which emission is observed from naphthalene with higher rotational energy. To obtain complete coverage of IR wavelengths relevant to the unidentified infrared bands (UIRs), UV laser-induced desorption was used to generate gas-phase highly excited PAHs. Lorentzian band shapes were convoluted with the monochromator-slit function in order to determine the widths of PAH emission bands under astrophysically relevant conditions. Bandwidths were also extracted from bands consisting of multiple normal modes blended together. These parameters are grouped according to the functional groups mostly involved in the vibration, and mean bandwidths are obtained. These bandwidths are larger than the widths of the corresponding UIR bands. However, when the comparison is limited to the largest PAHs studied, the bandwidths are slightly smaller than the corresponding UIR bands. These parameters can be used to model emission spectra from PAH cations and cations of larger PAHs, which are better candidate carriers of the UIRs.

Description: Efficient actuators that are lightweight, high performance and compact are needed to support telerobotic requirements for future NASA missions. In this work, we present a new class of electromechanically active polymers that can potentially be used as actuators to meet many NASA needs. The materials are graft elastomers that offer high strain under an applied electric field. Due to its higher mechanical modulus, this elastomer also has a higher strain energy density as compared to previously reported electrostrictive polyurethane elastomers. The dielectric, mechanical and electromechanical properties of this new electrostrictive elastomer have been studied as a function of temperature and frequency. Combined with structural analysis using x-ray diffraction and differential scanning calorimetry on the new elastomer, structure-property interrelationship and mechanisms of the electric field induced strain in the graft elastomer have also been investigated. This electroactive polymer (EAP) has demonstrated high actuation strain and high mechanical energy density. The combination of these properties with its tailorable molecular composition and excellent processability makes it attractive for a variety of actuation tasks. The experimental results and applications will be presented.

Description: An orbital emplacement for the transmitter and the antenna of a communications link at ELF (30 to 300 Hz) and VLF (3 kHz to 30 kHz) to submerged submarines has been considered since the very inception of the space age. However, only recently has space technology reached a sufficient level of maturity for system designers to undertake serious studies of this link configuration. The optimistic outlook stems from recent space technology developments, such as the design and construction by NASA of long orbiting tethers, and the testing, onboard Shuttle Orbiter ATLANTIS, of the first spaceborne 20 km metal wire. This is known as the Tethered Satellite System-1 (TSS-1), a space mission that might be possibly followed by other flights, with tether lengths that could reach 100 km. Once deployed at a height of, say, 300 km, from a Shuttle Orbiter, or from another suitable platform, a long, thin tether aligns itself along the local vertical by virtue of the gradient of the Earth gravity field. If made of metal, the tether can function as a VED (Vertical Electric Dipole) transmitting antenna at ELF and VLF.

Description: Analysis of the gravity gradiometer developed by Forward and Bell (1970) suggest that an accuracy, in the range 0.1 to 0.5 EU can be expected in a lunar orbiter application. This accuracy will allow gradient anomalies associated with mascons to be mapped with 1% accuracy and should reveal a great deal of new information about the lunar gravity field. The proposed experiment calls for putting such a gradiometer into a closely circular polar orbit at an average height of about 30 km above the lunar surface. This orbit allows the entire lunar surface to be covered in fourteen days, the gradiometer to be checked twice per revolution and results in successive passes above the lunar surface being spaced at about the resolution limit of about 30 km set both by the satellite altitude and instrumental integration time.

Description: Thermal calculations of objects near lunar surface, considering IR emission directivity effects