Planetary maps

USGS Publications Warehouse

,

1992-01-01

An important goal of the USGS planetary mapping program is to systematically map the geology of the Moon, Mars, Venus, and Mercury, and the satellites of the outer planets. These geologic maps are published in the USGS Miscellaneous Investigations (I) Series. Planetary maps on sale at the USGS include shaded-relief maps, topographic maps, geologic maps, and controlled photomosaics. Controlled photomosaics are assembled from two or more photographs or images using a network of points of known latitude and longitude. The images used for most of these planetary maps are electronic images, obtained from orbiting television cameras, various optical-mechanical systems. Photographic film was only used to map Earth's Moon.

Space telescope optical telescope assembly/scientific instruments. Phase B: -Preliminary design and program definition study; Volume 2A: Planetary camera report

NASA Technical Reports Server (NTRS)

1976-01-01

Development of the F/48, F/96 Planetary Camera for the Large Space Telescope is discussed. Instrument characteristics, optical design, and CCD camera submodule thermal design are considered along with structural subsystem and thermal control subsystem. Weight, electrical subsystem, and support equipment requirements are also included.

Printed Spacecraft Separation System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holmans, Walter; Dehoff, Ryan

In this project Planetary Systems Corporation proposed utilizing additive manufacturing (3D printing) to manufacture a titanium spacecraft separation system for commercial and US government customers to realize a 90% reduction in the cost and energy. These savings were demonstrated via “printing-in” many of the parts and sub-assemblies into one part, thus greatly reducing the labor associated with design, procurement, assembly and calibration of mechanisms. Planetary Systems Corporation redesigned several of the components of the separation system based on additive manufacturing principles including geometric flexibility and the ability to fabricate complex designs, ability to combine multiple parts of an assembly intomore » a single component, and the ability to optimize design for specific mechanical property targets. Shock absorption was specifically targeted and requirements were established to attenuate damage to the Lightband system from shock of initiation. Planetary Systems Corporation redesigned components based on these requirements and sent the designs to Oak Ridge National Laboratory to be printed. ORNL printed the parts using the Arcam electron beam melting technology based on the desire for the parts to be fabricated from Ti-6Al-4V based on the weight and mechanical performance of the material. A second set of components was fabricated from stainless steel material on the Renishaw laser powder bed technology due to the improved geometric accuracy, surface finish, and wear resistance of the material. Planetary Systems Corporation evaluated these components and determined that 3D printing is potentially a viable method for achieving significant cost and savings metrics.« less

Revised planetary protection policy for solar system exploration.

PubMed

DeVincenzi, D L; Stabekis, P D

1984-01-01

In order to control contamination of planets by terrestrial microorganisms and organic constituents, U.S. planetary missions have been governed by a planetary protection (or planetary quarantine) policy which has changed little since 1972. This policy has recently been reviewed in light of new information obtained from planetary exploration during the past decade and because of changes to, or uncertainties in, some parameters used in the existing quantitative approach. On the basis of this analysis, a revised planetary protection policy with the following key features is proposed: deemphasizing the use of mathematical models and quantitative analyses; establishing requirements for target planet/mission type (i.e., orbiter, lander, etc.) combinations; considering sample return missions a separate category; simplifying documentation; and imposing implementing procedures (i.e., trajectory biasing, cleanroom assembly, spacecraft sterilization, etc.) by exception, i.e., only if the planet/mission combination warrants such controls.

Summary of the Second International Planetary Dunes Workshop: Planetary Analogs - Integrating Models, Remote Sensing, and Field Data, Alamosa, Colorado, USA, May 18-21, 2010

USGS Publications Warehouse

Fenton, L.K.; Bishop, M.A.; Bourke, M.C.; Bristow, C.S.; Hayward, R.K.; Horgan, B.H.; Lancaster, N.; Michaels, T.I.; Tirsch, D.; Titus, T.N.; Valdez, A.

2010-01-01

The Second International Planetary Dunes Workshop took place in Alamosa, Colorado, USA from May 18-21, 2010. The workshop brought together researchers from diverse backgrounds to foster discussion and collaboration regarding terrestrial and extra-terrestrial dunes and dune systems. Two and a half days were spent on five oral sessions and one poster session, a full-day field trip to Great Sand Dunes National Park, with a great deal of time purposefully left open for discussion. On the last day of the workshop, participants assembled a list of thirteen priorities for future research on planetary dune systems. ?? 2010.

Preparation of Mo-Re-C samples containing Mo7Re13C with the β-Mn-type structure by solid state reaction of planetary-ball-milled powder mixtures of Mo, Re and C, and their crystal structures and superconductivity

NASA Astrophysics Data System (ADS)

Oh-ishi, Katsuyoshi; Nagumo, Kenta; Tateishi, Kazuya; Takafumi, Ohnishi; Yoshikane, Kenta; Sugiyama, Machiko; Oka, Kengo; Kobayashi, Ryota

2017-01-01

Mo-Re-C compounds containing Mo7Re13C with the β-Mn structure were synthesized with high-melting-temperature metals Mo, Re, and C powders using a conventional solid state method with a planetary ball milling machine instead of the arc melting method. Use of the ball milling machine was necessary to obtain Mo7Re13C with the β-Mn structure using the solid state method. Almost single-phase Mo7Re13C with a trace of impurity were obtained using the synthesis method. By XRF and lattice parameter measurements on the samples, Fe element existed in the compound synthesized using the planetary ball milling machine with a pot and balls made of steel, though Fe element was not detected in the compound synthesized using a pot and balls made of tungsten carbide. The former compound containg the Fe atom did not show superconductivity but the latter compound without the Fe atom showed superconductivity at 6.1 K.

Developing planetary protection technology- microbial diversity of the Mars Orbiter Odyssey and the spacecraft assembly and encapsulation facility II

NASA Technical Reports Server (NTRS)

Duc, M. La; Chen, F.; Kern, R.; Koukol, R.; Baker, A.; Venkateswaran, K.

2001-01-01

A study in which several surface samples, retrieved from both the Mars Odyssey Spacecraft and the Kennedy Space Center (KSC) Spacecraft Assembly and Encapsulation Facility II (SAEF-II), were prcesed and evaluated by both molecular and traditional culture-based methods for the microbial diversity.

Tools and methods for automated assembly of miniaturized gear systems

NASA Astrophysics Data System (ADS)

Nienhaus, Matthias; Ehrfeld, Wolfgang; Berg, Udo; Schmitz, Felix; Soultan, H.

2000-10-01

The assembly of gear systems with the size of a pin head is almost beyond the bound of human tactile skills. The magic formula for series fabrication of this hybrid micro systems is the automation of the assembly process. As a contribution, this paper presents and discusses three different assembly methods comprising specifically developed tools for different types of planetary gears with outer diameters of 1.9 mm. Because of the huge importance for the complete micro assembly process, particular attention will be dedicated to the feeding and magazining of the micro gear components. Starting with metallic gear wheels as bulk good, an extremely miniaturized gear system of the Wolfram type has been automatically assembled by employing the strategy of tolerance compensation movement. As a key component, a modular tong gripper with specifically adapted gripping jaws produced by LIGA technology has been used. Further detailed investigations were spend on handling and assembly of micro injection moulded gear wheels made of POM for a three state planetary gear system. One strategy, following the idea of in situ observation, focuses on the intensive use of electronic pattern recognition. Alternatively, an unusual method based on a novel plastic wafer magazine will be discussed in detail. Hereby the exact position and orientation of injection moulded micro components will be presented from the manufacturing process up to the final micro assembly procedure. By simplifying the moulding of the micro gears as well as their handling, storing and assembly, this method has the potential to revolutionize the series fabrication of products with dimensions in the microscopic range in general.

Bi-directional Reflectance of Icy Surface Analogs: A Dual Approach

NASA Astrophysics Data System (ADS)

Quinones, Juan Manuel; Vides, Christina; Nelson, Robert M.; Boryta, Mark; Mannat, Ken s.

2018-01-01

Bi-directional reflectance measurements of analogs for planetary regolith have provided insight into the surface properties of planetary satellites and small bodies. Because Aluminum Oxide (Al2O3) and water ice share a similar hexagonal crystalline structure, the former has been used in laboratory experiments to simulate the regolith of both icy and dusty planetary bodies. By measuring various sizes of well sorted size fractions of Al2O3, the reflectance phase curve and porosity of a planetary regolith can be determined. We have designed an experiment to test the laboratory measurements produced by Nelson et al. (2000). Additionally, we made reflectance measurements for other alkali-halide compounds that could be used for applications beyond astronomy and planetary science.In order to provide an independent check on the Nelson et al. data, we designed an instrument with a different configuration. While both instruments take bidirectional reflectance measurements, our instrument, the Rigid Photometric Goniometer (RPG), is fixed at a phase angle of 5° and detects the scattered light with a photomultiplier tube (PMT). The PMT current is then measured with an electrometer. Following the example of Nelson et al., we measured the bidirectional reflectance of Al2O3 particulate size fractions between 0.1

Compact rotary sequencer

NASA Technical Reports Server (NTRS)

Appleberry, W. T.

1980-01-01

Rotary sequencer is assembled from conventional planetary differential gearset and latching mechanism utilizing inputs and outputs which are coaxial. Applications include automated production-line equipment in home appliances and in vehicles.

Thermal Design and Analysis of the Optical Telescope Assembly for the Gondola for High Altitude Planetary Science

NASA Technical Reports Server (NTRS)

O'Connor, Brian; Brooks, Thomas

2017-01-01

The NASA Gondola for High Altitude Planetary Science (GHAPS) project is an effort to design, build, and fly a balloon-borne platform for planetary science missions. GHAPS observations will be in the 300 nm to 5 micron wavelength region covering UV, visible, and near-mid IR. The primary element of the project is the Optical Telescope Assembly (OTA). It is a one meter aperture narrow-field-of-view telescope that contains the primary and secondary mirrors, the support system/metering structure, a secondary mirror focusing system, baffles, and insulation. This paper presents the thermal design and analysis that has been done to support the design of the OTA. A major part of the thermal analysis was bounding the flight environment for the six potential Columbia Scientific Balloon Facility launch sites. These analyses were used to give input into the Structural Thermal Optical Performance (STOP) analysis of the telescope. Also the analysis was used to select heater sizes for the few OTA associated electronic components. Currently the telescope is scheduled to have its first flight in 2019.

Current Status of a NASA High-Altitude Balloon-Based Observatory for Planetary Science

NASA Technical Reports Server (NTRS)

Varga, Denise M.; Dischner, Zach

2015-01-01

Recent studies have shown that progress can be made on over 20% of the key questions called out in the current Planetary Science Decadal Survey by a high-altitude balloon-borne observatory. Therefore, NASA has been assessing concepts for a gondola-based observatory that would achieve the greatest possible science return in a low-risk and cost-effective manner. This paper addresses results from the 2014 Balloon Observation Platform for Planetary Science (BOPPS) mission, namely successes in the design and performance of the Fine Pointing System. The paper also addresses technical challenges facing the new Gondola for High Altitude Planetary Science (GHAPS) reusable platform, including thermal control for the Optical Telescope Assembly, power generation and management, and weight-saving considerations that the team will be assessing in 2015 and beyond.

Submillimeter Planetary Atmospheric Chemistry Exploration Sounder

NASA Technical Reports Server (NTRS)

Schlecht, Erich T.; Allen, Mark A.; Gill, John J.; Choonsup, Lee; Lin, Robert H.; Sin, Seth; Mehdi, Imran; Siegel, Peter H.; Maestrini, Alain

2013-01-01

Planetary Atmospheric Chemistry Exploration Sounder (SPACES), a high-sensitivity laboratory breadboard for a spectrometer targeted at orbital planetary atmospheric analysis. The frequency range is 520 to 590 GHz, with a target noise temperature sensitivity of 2,500 K for detecting water, sulfur compounds, carbon compounds, and other atmospheric constituents. SPACES is a prototype for a powerful tool for the exploration of the chemistry and dynamics of any planetary atmosphere. It is fundamentally a single-pixel receiver for spectral signals emitted by the relevant constituents, intended to be fed by a fixed or movable telescope/antenna. Its front-end sensor translates the received signal down to the 100-MHz range where it can be digitized and the data transferred to a spectrum analyzer for processing, spectrum generation, and accumulation. The individual microwave and submillimeter wave components (mixers, LO high-powered amplifiers, and multipliers) of SPACES were developed in cooperation with other programs, although with this type of instrument in mind. Compared to previous planetary and Earth science instruments, its broad bandwidth (approx. =.13%) and rapid tunability (approx. =.10 ms) are new developments only made possible recently by the advancement in submillimeter circuit design and processing at JPL.

Mars pathfinder Rover egress deployable ramp assembly

NASA Technical Reports Server (NTRS)

Spence, Brian R.; Sword, Lee F.

1996-01-01

The Mars Pathfinder Program is a NASA Discovery Mission, led by the Jet Propulsion Laboratory, to launch and place a small planetary Rover for exploration on the Martian surface. To enable safe and successful egress of the Rover vehicle from the spacecraft, a pair of flight-qualified, deployable ramp assemblies have been developed. This paper focuses on the unique, lightweight deployable ramp assemblies. A brief mission overview and key design requirements are discussed. Design and development activities leading to qualification and flight systems are presented.

Photodegradation of selected organics on Mars

NASA Astrophysics Data System (ADS)

ten Kate, I. L.; Boosman, A.; Fornaro, T.; King, H. E.; Kopacz, K. A.; Wolthers, M.

2017-09-01

At least as much as 2.4 million kg of unaltered organic material is estimated to be delivered to the Martian surface each year. However, intense UV irradiation and the highly oxidizing and acidic nature of Martian soil cause degradation of organic compounds. Here we present first results obtained with the recently developed PALLAS facility at Utrecht University. This facility is specifically designed to simulate planetary and asteroid surface conditions to study the photocatalytic properties of relevant planetary minerals. Our results tentatively show degradation of several compounds and preservation of others.

The Impact and Oxidation Survival of Selected Meteoritic Compounds: Signatures of Asteroid Organic Material on Planetary Surfaces

NASA Technical Reports Server (NTRS)

Cooper, George; Horz, Fred; Oleary, Alanna; Chang, Sherwood

2013-01-01

Polar, non-volatile organic compounds may be present on the surfaces (or near surfaces) of multiple Solar System bodies. If found, by current or future missions, it would be desirable to determine the origin(s) of such compounds, e.g., asteroidal or in situ. To test the possible survival of meteoritic compounds both during impacts with planetary surfaces and under subsequent (possibly) harsh ambient conditions, we subjected known meteoritic compounds to relatively high impact-shock pressures and/or to varying oxidizing/corrosive conditions. Tested compounds include sulfonic and phosphonic acids (S&P), polyaromatic hydrocarbons (PAHs) amino acids, keto acids, dicarboxylic acids, deoxy sugar acids, and hydroxy tricarboxylic acids (Table 1). Meteoritic sulfonic acids were found to be relatively abundant in the Murchison meteorite and to possess unusual S-33 isotope anomalies (non mass-dependent isotope fractionations). Combined with distinctive C-S and C-P bonds, the S&P are potential signatures of asteroidal organic material.

High-resolution simulations of the final assembly of Earth-like planets. 2. Water delivery and planetary habitability.

PubMed

Raymond, Sean N; Quinn, Thomas; Lunine, Jonathan I

2007-02-01

The water content and habitability of terrestrial planets are determined during their final assembly, from perhaps 100 1,000-km "planetary embryos " and a swarm of billions of 1-10-km "planetesimals. " During this process, we assume that water-rich material is accreted by terrestrial planets via impacts of water-rich bodies that originate in the outer asteroid region. We present analysis of water delivery and planetary habitability in five high-resolution simulations containing about 10 times more particles than in previous simulations. These simulations formed 15 terrestrial planets from 0.4 to 2.6 Earth masses, including five planets in the habitable zone. Every planet from each simulation accreted at least the Earth's current water budget; most accreted several times that amount (assuming no impact depletion). Each planet accreted at least five water-rich embryos and planetesimals from the past 2.5 astronomical units; most accreted 10-20 water-rich bodies. We present a new model for water delivery to terrestrial planets in dynamically calm systems, with low-eccentricity or low-mass giant planets-such systems may be very common in the Galaxy. We suggest that water is accreted in comparable amounts from a few planetary embryos in a " hit or miss " way and from millions of planetesimals in a statistically robust process. Variations in water content are likely to be caused by fluctuations in the number of water-rich embryos accreted, as well as from systematic effects, such as planetary mass and location, and giant planet properties.

Microbial diversity in European and South American spacecraft assembly clean rooms

NASA Astrophysics Data System (ADS)

Moissl-Eichinger, Christine; Stieglmeier, Michaela; Schwendner, Petra

Spacecraft assembly clean rooms are unique environments for microbes: Due to low nutri-ent levels, desiccated, clean conditions, constant control of humidity and temperature, these environments are quite inhospitable to microbial life and even considered "extreme". Many procedures keep the contamination as low as possible, but these conditions are also highly se-lective for indigenous microbial communities. For space missions under planetary protection requirements, it is crucial to control the contaminating bioburden as much as possible; but for the development of novel cleaning/sterilization methods it is also important to identify and characterize (understand) the present microbial community of spacecraft clean rooms. In prepa-ration for the recently approved ESA ExoMars mission, two European and one South American spacecraft assembly clean rooms were analyzed with respect to their microbial diversity, using standard procedures, new cultivation approaches and molecular methods, that should shed light onto the presence of planetary protection relevant microorganisms. For this study, the Her-schel Space Observatory (launched in May 2009) and its housing clean rooms in Friedrichshafen (Germany), at ESTEC (The Netherlands) and CSG, Kourou (French Guyana) were sampled during assembly, test and launch operations. Although Herschel does not demand planetary protection requirements, all clean rooms were in a fully operating state during sampling. This gave us the opportunity to sample the microbial diversity under strict particulate and molecular contamination-control. Samples were collected from spacecraft and selected clean room surface areas and were subjected to cultivation assays (32 different media), molecular studies (based on 16S rRNA gene sequence analysis) and quantitative PCR. The results from different strategies will be compared and critically discussed, showing the advantages and limits of the selected methodologies. This talk will sum up the lessons learned from this microbial diversity project.

Life beyond the solar system.

NASA Technical Reports Server (NTRS)

Sagan, C.

1972-01-01

Review of some of the highlights and more recent developments in the search for extraterrestrial intelligence. The first major problem is one of the generality of the formation of planetary systems. Observations of the nearest stars which are not members of binary or multiple stars indicates that fully half have companions of planetary mass. The presence of organic compounds in meteorites, probably in Jovian planets, in comets, in the interstellar medium, and in cool stars implies that the production of organic compounds essential for the origin of life should be pervasive throughout the universe. Possibilities of interstellar communication are discussed.

Detecting aromatic compounds on planetary surfaces using ultraviolet time-resolved fluorescence spectroscopy

NASA Astrophysics Data System (ADS)

Eshelman, E.; Daly, M. G.; Slater, G.; Cloutis, E.

2018-02-01

Many aromatic organic molecules exhibit strong and characteristic fluorescence when excited with ultraviolet radiation. As laser excitation in the ultraviolet generates both fluorescence and resonantly enhanced Raman scattering of aromatic vibrational modes, combined Raman and fluorescence instruments have been proposed to search for organic compounds on Mars. In this work the time-resolved fluorescence of a suite of 24 compounds composed of 2-5 ringed alternant, non-alternant, and heterocyclic PAHs was measured. Fluorescence instrumentation with similar specifications to a putative flight instrument was capable of observing the fluorescence decay of these compounds with a sub-ns resolution. Incorporating time-resolved capabilities was also found to increase the ability to discriminate between individual PAHs. Incorporating time-resolved fluorescence capabilities into an ultraviolet gated Raman system intended for a rover or lander can increase the ability to detect and characterize PAHs on planetary surfaces.

High surface area graphene-supported metal chalcogenide assembly

DOEpatents

Worsley, Marcus A.; Kuntz, Joshua D.; Orme, Christine A.

2017-04-25

Disclosed here is a method for hydrocarbon conversion, comprising contacting at least one graphene-supported assembly with at least one hydrocarbon feedstock, wherein the graphene-supported assembly comprises (i) a three-dimensional network of graphene sheets crosslinked by covalent carbon bonds and (ii) at least one metal chalcogenide compound disposed on the graphene sheets, wherein the chalcogen of the metal chalcogenide compound is selected from S, Se and Te, and wherein the metal chalcogenide compound accounts for at least 20 wt. % of the graphene-supported assembly.

What Is Life? What Was Life? What Will Life Be?

NASA Astrophysics Data System (ADS)

Deamer, D.

Our laboratory is exploring self-assembly processes and polymerization reactions of organic compounds in natural geothermal environments and related laboratory simulations. Although the physical environment that fostered primitive cellular life is still largely unconstrained, we can be reasonably confident that liquid water was required, together with a source of organic compounds and energy to drive polymerization reactions. There must also have been a process by which the compounds were sufficiently concentrated to undergo physical and chemical interactions. In earlier work we observed that macromolecules such as nucleic acids and proteins are readily encapsulated in membranous boundaries during wet-dry cycles such as those that would occur at the edges of geothermal springs or tide pools. The resulting structures are referred to as protocells, in that they exhibit certain properties of living cells and are models of the kinds of encapsulated macromolecular systems that would have led toward the first forms of cellular life. However, the assembly of protocells is markedly inhibited by conditions associated with extreme environments: High temperature, high salt concentrations, and low pH ranges. From a biophysical perspective, it follows that the most plausible planetary environment for the origin of cellular life would be an aqueous phase at moderate temperature ranges and low ionic strength, having a pH value near neutrality and divalent cations at submillimolar concentrations. This suggestion is in marked contrast to the view that life most likely began in a geothermal or marine environment, perhaps even the extreme environment of a hydrothermal vent. A more plausible site for the origin of cellular life would be fresh water pools maintained by rain falling on volcanic land masses resembling present-day Hawaii and Iceland. After the first cellular life was able to establish itself in a relatively benign environment, it would rapidly begin to adapt through Darwinian selection to more rigorous environments, including the extreme temperatures, salt concentrations and pH ranges that we now associate with the limits of life on the Earth.

International Agreement on Planetary Protection

NASA Technical Reports Server (NTRS)

2000-01-01

The maintenance of a NASA policy, is consistent with international agreements. The planetary protection policy management in OSS, with Field Center support. The advice from internal and external advisory groups (NRC, NAC/Planetary Protection Task Force). The technology research and standards development in bioload characterization. The technology research and development in bioload reduction/sterilization. This presentation focuses on: forward contamination - research on the potential for Earth life to exist on other bodies, improved strategies for planetary navigation and collision avoidance, and improved procedures for sterile spacecraft assembly, cleaning and/or sterilization; and backward contamination - development of sample transfer and container sealing technologies for Earth return, improvement in sample return landing target assessment and navigation strategy, planning for sample hazard determination requirements and procedures, safety certification, (liaison to NEO Program Office for compositional data on small bodies), facility planning for sample recovery system, quarantine, and long-term curation of 4 returned samples.

Preparation of Mo-Re-C samples containing Mo{sub 7}Re{sub 13}C with the β-Mn-type structure by solid state reaction of planetary-ball-milled powder mixtures of Mo, Re and C, and their crystal structures and superconductivity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oh-ishi, Katsuyoshi, E-mail: oh-ishi@kc.chuo-u.ac.jp; Nagumo, Kenta; Tateishi, Kazuya

Mo-Re-C compounds containing Mo{sub 7}Re{sub 13}C with the β-Mn structure were synthesized with high-melting-temperature metals Mo, Re, and C powders using a conventional solid state method with a planetary ball milling machine instead of the arc melting method. Use of the ball milling machine was necessary to obtain Mo{sub 7}Re{sub 13}C with the β-Mn structure using the solid state method. Almost single-phase Mo{sub 7}Re{sub 13}C with a trace of impurity were obtained using the synthesis method. By XRF and lattice parameter measurements on the samples, Fe element existed in the compound synthesized using the planetary ball milling machine with amore » pot and balls made of steel, though Fe element was not detected in the compound synthesized using a pot and balls made of tungsten carbide. The former compound containg the Fe atom did not show superconductivity but the latter compound without the Fe atom showed superconductivity at 6.1 K. - Graphical abstract: Temperature dependence of the magnetic susceptibility measured under 10 Oe for the superconducting PBM-T samples without Fe element and non-superconducting PBM-S with Fe element. The inset is the enlarged view of the data for the PBM-S sample.« less

Capability 9.3 Assembly and Deployment

NASA Technical Reports Server (NTRS)

Dorsey, John

2005-01-01

Large space systems are required for a range of operational, commercial and scientific missions objectives however, current launch vehicle capacities substantially limit the size of space systems (on-orbit or planetary). Assembly and Deployment is the process of constructing a spacecraft or system from modules which may in turn have been constructed from sub-modules in a hierarchical fashion. In-situ assembly of space exploration vehicles and systems will require a broad range of operational capabilities, including: Component transfer and storage, fluid handling, construction and assembly, test and verification. Efficient execution of these functions will require supporting infrastructure, that can: Receive, store and protect (materials, components, etc.); hold and secure; position, align and control; deploy; connect/disconnect; construct; join; assemble/disassemble; dock/undock; and mate/demate.

Reflection spectra, 2.5-7 microns, of some solids of planetary interest

NASA Technical Reports Server (NTRS)

Fink, U.; Burk, S. D.

1973-01-01

Reflection spectra of 42 compounds of possible planetary interest were run from 2.5 to 7 microns. They were supplemented by some transmission spectra extending the wavelength coverage to 15 microns. The spectra were organized according to their constituent radicals and an attempt was made at the identification of the absorption features.

Hydrogen bonding directed self-assembly of small-molecule amphiphiles in water.

PubMed

Xu, Jiang-Fei; Niu, Li-Ya; Chen, Yu-Zhe; Wu, Li-Zhu; Tung, Chen-Ho; Yang, Qing-Zheng

2014-08-01

Compounds comprising one or two quadruply hydrogen bonding units, 2-ureido-4[1H]-pyrimidinone (UPy) and tris(tetraethylene glycol monomethyl ether) moieties, were reported to form highly stable hydrogen-bonded assemblies in water. Compound 1, containing one UPy, assembles into vesicles, and compound 2, containing two UPy units, forms micelles. The aggregates disassemble reversibly when the solution pH is raised to 9.0 or above. The results demonstrate the utility of hydrogen bonding to direct the self-assembly of small-molecule building blocks in aqueous media.

Astrobiological Implications of Titan Tholin in Methane Lakes

NASA Astrophysics Data System (ADS)

Khare, Bishun N.; McKay, C. P.; McPherson, S.; Cruikshank, D.; Nna-Mvondo, D.; Sekine, Y.

2010-10-01

We report here on our ongoing research in the Laboratory for Planetary Studies at NASA Ames Research Center dedicated to determine the degree of solubility of Titan tholin in the methane-ethane lakes. Our work is also directed toward confirming the presence of any astrobiologically significant molecules via hydrolysis and pyrolysis of a simulated lake sample. Our previous work conducted at Cornell University and subsequently in the Laboratory for Planetary Studies at NASA Ames Research Center has established that Titan tholin produces amino acids (Khare et al. Icarus 1986) on hydrolysis, and many compounds including adenine on pyrolysis (Khare et al. Adv. Space Res. 1984). Also, our previous work by Thompson et al. (Icarus 1991) has clearly indicated that when energy is supplied to Titan's atmospheric composition (methane and nitrogen), tholin results from hundreds of contemporary compounds, including highly reactive compounds such as azides and isocyanides. Cassini showed that photolysis of methane produces benzene and many polycyclic aromatic hydrocarbons, along with compounds with very high molecular weights (up to 10000 amu), resulting from the photolytic reactions of CH4 with nitrogen. These heavy aerosols, termed "tholins” by Sagan and Khare (Nature 1979), are also synthesized when Titan intercepts charged particles from the magnetosphere of Saturn. Tholins resulting from both of these syntheses eventually descend to the surface of Titan, where some quantity collects in the methane-ethane lakes. This research is supported by a grant from Planetary Atmospheres.

Photochemical Formation of Aerosol in Planetary Atmospheres: Photon and Water Mediated Chemistry of SO_2

NASA Astrophysics Data System (ADS)

Kroll, Jay A.; Donaldson, D. J.; Vaida, Veronica

2016-06-01

Sulfur compounds have been observed in a number of planetary atmospheres throughout our solar system. Our current understanding of sulfur chemistry explains much of what we observe in Earth's atmosphere. However, several discrepancies between modeling and observations of the Venusian atmosphere show there are still problems in our fundamental understanding of sulfur chemistry. This is of particular concern due to the important role sulfur compounds play in the formation of aerosols, which have a direct impact on planetary climates, including Earth's. We investigate the role of water complexes in the hydration of sulfur oxides and dehydration of sulfur acids and will present spectroscopic studies to document such effects. I will present recent work investigating mixtures of SO_2 and water that generate large quantities of aerosol when irradiated with solar UV light, even in the absence of traditional OH chemistry. I will discuss a proposed mechanism for the formation of sulfurous acid (H_2SO_3) and present recent experimental work that supports this proposed mechanism. Additionally, the implications that photon-induced hydration of SO_2 has for aerosol formation in the atmosphere of earth as well as other planetary atmospheres will be discussed.

European Geophysical Society (23rd) General Assembly, Annales Geophysicae, Part 3, Space & Planetary Sciences, Supplement 3 to Volume 16 Held in Nice, France on 20-24 April 1998

DTIC Science & Technology

1998-01-01

For the lower stratosphere diabatic heating sources and planetary wave activity will be discussed. Above 10 hPa observations are less frequent and...the observation durations being minutes-days; ~30 to 200 samples covering each source of the disturbances. The authors have been supported by STCU...the "classical" sinks. The observed stratospheric N20 mixing ratios will not be perturbed by the new source because of: (1) the inevitable loss

Exposing Microorganisms in the Stratosphere for Planetary Protection Project

NASA Technical Reports Server (NTRS)

Smith, David J. (Compiler)

2015-01-01

Earths stratosphere is similar to the surface of Mars: rarified air which is dry, cold, and irradiated. E-MIST is a balloon payload that has 4 independently rotating skewers that hold known quantities of spore-forming bacteria isolated from spacecraft assembly facilities at NASA. Knowing the survival profile of microbes in the stratosphere can uniquely contribute to NASA Planetary Protection for Mars.Objectives 1. Collect environmental data in the stratosphere to understand factors impacting microbial survival. 2. Determine of surviving microbes (compared to starting quantities). 3. Examine microbial DNA mutations induced by stratosphere exposure.

Report on the 2015 COSPAR Panel on Planetary Protection Colloquium

NASA Astrophysics Data System (ADS)

Hipkin, Victoria; Kminek, Gerhard

2016-07-01

In consultation with the COSPAR Scientific Commissions B (Space Studies of the Earth-Moon System, Planets, and Small Bodies of the Solar System) and F (Life Sciences as Related to Space), the COSPAR Panel on Planetary Protection organised a colloquium at the International Space Science Institute (ISSI) in Bern, Switzerland, in September 2015, to cover two pertinent topics: * Icy moon sample return planetary protection requirements * Mars Special Regions planetary protection requirements These two topics were addressed in two separate sessions. Participation from European, North American and Japanese scientists reflected broad expertise from the respective COSPAR Commissions, recent NASA MEPAG Science Analysis Group and National Academies of Sciences, Engineering, and Medicine/European Science Foundation Mars Special Regions Review Committee. The recommendations described in this report are based on discussions that took place during the course of the colloquium and reflect a consensus of the colloquium participants that participated in the two separate sessions. These recommendations are brought to the 2016 COSPAR Scientific Assembly for further input and discussion as part of the recognised process for updating COSPAR Planetary Protection Policy.

Self-assemblies of luminescent rare earth compounds in capsules and multilayers.

PubMed

Zhang, Renjie; Shang, Juanjuan; Xin, Jing; Xie, Beibei; Li, Ya; Möhwald, Helmuth

2014-05-01

This review addresses luminescent rare earth compounds assembled in microcapsules as well as in planar films fabricated by the layer-by-layer (LbL) technique, the Langmuir-Blodgett (LB) method and in self-assembled monolayers. Chemical precipitation, electrostatic, van der Waals interactions and covalent bonds are involved in the assembly of these compounds. Self-organized ring patterns of rare earth complexes in Langmuir monolayers and on planar surfaces with stripe patterns, as well as fluorescence enhancement due to donor-acceptor pairs, microcavities, enrichment of rare earth compounds, and shell protection against water are described. Recent information on the tuning of luminescence intensity and multicolors by the excitation wavelength and the ratio of rare earth ions, respectively, are also reviewed. Potential applications of luminescent rare earth complex assemblies serving as biological probes, temperature and gas sensors are pointed out. Copyright © 2014 Elsevier B.V. All rights reserved.

The Mars Plant Growth Experiment and Implications for Planetary Protection

NASA Astrophysics Data System (ADS)

Smith, Heather

Plants are the ultimate and necessary solution for O2 production at a human base on Mars. Currently it is unknown if seeds can germinate on the Martian surface. The Mars Plant growth experiment (MPX) is a proposal for the first step in the development of a plant- based O2 production system by demonstrating plant germination and growth on the Martian surface. There is currently no planetary protection policy in place that covers plants on the Martian surface. We describe a planetary protection plan in compliance with NASA and COSPAR policy for a closed plant growth chamber on a Mars rover. We divide the plant growth chamber into two categories for planetary protection, the Outside: the outside of the chamber exposed to the Martian environment, and the Inside: the inside of the chamber which is sealed off from Mars atmosphere and contains the plant seeds and ancillary components for seed growth. We will treat outside surfaces of the chamber as other outside surfaces on the rover, wiped with a mixture of isopropyl alcohol and water as per Category IVb planetary protection requirements. All internal components of the MPX except the seeds and camera (including the water system, the plant growth stage and interior surface walls) will be sterilized by autoclave and subjected to sterilizing dry heat at a temperature of 125°C at an absolute humidity corresponding to a relative humidity of less than 25 percent referenced to the standard conditions of 0°C and 760 torr pressure. The seeds and internal compartments of the MPX in contact with the growth media will be assembled and tested to be free of viable microbes. MPX, once assembled, cannot survive Dry Heat Microbial Reduction. The camera with the radiation and CO2 sensors will be sealed in their own container and vented through HEPA filters. The seeds will be vernalized (microbe free) as per current Space Station methods described by Paul et al. 2001. Documentation of the lack of viable microbes on representative seeds from the same seed lot as used in the flight unit and lack of viable microbes in the interior of the MPX will be confirmed by the assay methods outlined in NASA HDBK 6022. In this method surfaces are swabbed and the cells collected on the swabs are extracted and then cultured following a standard protocol. All operations involving the manipulation of sterile items and sample processing shall be performed in laminar flow environments meeting Class 100 air cleanliness requirements of Federal Standard 209B. The entire MPX will be assembled in a sterile environment within a month of launch if possible, but could withstand an earlier assembly if required.

Functional Metagenomics of Spacecraft Assembly Cleanrooms: Presence of Virulence Factors Associated with Human Pathogens

PubMed Central

Bashir, Mina; Ahmed, Mahjabeen; Weinmaier, Thomas; Ciobanu, Doina; Ivanova, Natalia; Pieber, Thomas R.; Vaishampayan, Parag A.

2016-01-01

Strict planetary protection practices are implemented during spacecraft assembly to prevent inadvertent transfer of earth microorganisms to other planetary bodies. Therefore, spacecraft are assembled in cleanrooms, which undergo strict cleaning and decontamination procedures to reduce total microbial bioburden. We wanted to evaluate if these practices selectively favor survival and growth of hardy microorganisms, such as pathogens. Three geographically distinct cleanrooms were sampled during the assembly of three NASA spacecraft: The Lockheed Martin Aeronautics' Multiple Testing Facility during DAWN, the Kennedy Space Center's Payload Hazardous Servicing Facility (KSC-PHSF) during Phoenix, and the Jet Propulsion Laboratory's Spacecraft Assembly Facility during Mars Science Laboratory. Sample sets were collected from the KSC-PHSF cleanroom at three time points: before arrival of the Phoenix spacecraft, during the assembly and testing of the Phoenix spacecraft, and after removal of the spacecraft from the KSC-PHSF facility. All samples were subjected to metagenomic shotgun sequencing on an Illumina HiSeq 2500 platform. Strict decontamination procedures had a greater impact on microbial communities than sampling location Samples collected during spacecraft assembly were dominated by Acinetobacter spp. We found pathogens and potential virulence factors, which determine pathogenicity in all the samples tested during this study. Though the relative abundance of pathogens was lowest during the Phoenix assembly, potential virulence factors were higher during assembly compared to before and after assembly, indicating a survival advantage. Decreased phylogenetic and pathogenic diversity indicates that decontamination and preventative measures were effective against the majority of microorganisms and well implemented, however, pathogen abundance still increased over time. Four potential pathogens, Acinetobacter baumannii, Acinetobacter lwoffii, Escherichia coli and Legionella pneumophila, and their corresponding virulence factors were present in all cleanroom samples. This is the first functional metagenomics study describing presence of pathogens and their corresponding virulence factors in cleanroom environments. The results of this study should be considered for microbial monitoring of enclosed environments such as schools, homes, hospitals and more isolated habitation such the International Space Station and future manned missions to Mars. PMID:27667984

OSIRIS-REx OCAMS detector assembly characterization

NASA Astrophysics Data System (ADS)

Hancock, J.; Crowther, B.; Whiteley, M.; Burt, R.; Watson, M.; Nelson, J.; Fellows, C.; Rizk, B.; Kinney-Spano, E.; Perry, M.; Hunten, M.

2013-09-01

The OSIRIS-REx asteroid sample return mission carries a suite of three cameras referred to as OCAMS. The Space Dynamics Laboratory (SDL) at Utah State University is providing the CCD-based detector assemblies for OCAMS to the Lunar Planetary Lab (LPL) at the University of Arizona. Working with the LPL, SDL has designed the electronics to operate a 1K by 1K frame transfer Teledyne DALSA Multi-Pinned Phase (MPP) CCD. The detector assembly electronics provides the CCD clocking, biasing, and digital interface with the OCAMS payload Command Control Module (CCM). A prototype system was built to verify the functionality of the detector assembly design and to characterize the detector system performance at the intended operating temperatures. The characterization results are described in this paper.

Outpost Assembly Using the ATHLETE Mobility System

NASA Technical Reports Server (NTRS)

Howe, A. Scott; Wilcox, Brian

2016-01-01

A planetary surface outpost will likely consist of elements delivered on multiple manifests, that will need to be assembled from a scattering of landings. Using the All-Terrain Hex-Limbed Extra-Terrestrial Explorer (ATHLETE) limbed robotic mobility system, the outpost site can be prepared in advance through leveling, paving, and in-situ structures. ATHLETE will be able to carry pressurized and non-pressurized payloads overland from the lander descent stage to the outpost location, and perform precision docking and assembly of components. In addition, spent descent stages can be carried to assembly locations to form elevated decks for external work platforms above the planet surface. This paper discusses several concepts that have been studied for possible inclusion in the NASA Evolvable Mars Campaign human exploration mission scenarios.

SmallSat Innovations for Planetary Science

NASA Astrophysics Data System (ADS)

Weinberg, Jonathan; Petroy, Shelley; Roark, Shane; Schindhelm, Eric

2017-10-01

As NASA continues to look for ways to fly smaller planetary missions such as SIMPLEX, MoO, and Venus Bridge, it is important that spacecraft and instrument capabilities keep pace to allow these missions to move forward. As spacecraft become smaller, it is necessary to balance size with capability, reliability and payload capacity. Ball Aerospace offers extensive SmallSat capabilities matured over the past decade, utilizing our broad experience developing mission architecture, assembling spacecraft and instruments, and testing advanced enabling technologies. Ball SmallSats inherit their software capabilities from the flight proven Ball Configurable Platform (BCP) line of spacecraft, and may be tailored to meet the unique requirements of Planetary Science missions. We present here recent efforts in pioneering both instrument miniaturization and SmallSat/sensorcraft development through mission design and implementation. Ball has flown several missions with small, but capable spacecraft. We also have demonstrated a variety of enhanced spacecraft/instrument capabilities in the laboratory and in flight to advance autonomy in spaceflight hardware that can enable some small planetary missions.

Self-assembling peptide amphiphiles and related methods for growth factor delivery

DOEpatents

Stupp, Samuel I [Chicago, IL; Donners, Jack J. J. M.; Silva, Gabriel A [Chicago, IL; Behanna, Heather A [Chicago, IL; Anthony, Shawn G [New Stanton, PA

2009-06-09

Amphiphilic peptide compounds comprising one or more epitope sequences for binding interaction with one or more corresponding growth factors, micellar assemblies of such compounds and related methods of use.

Self-assembling peptide amphiphiles and related methods for growth factor delivery

DOEpatents

Stupp, Samuel I [Chicago, IL; Donners, Jack J. J. M.; Silva, Gabriel A [Chicago, IL; Behanna, Heather A [Chicago, IL; Anthony, Shawn G [New Stanton, PA

2012-03-20

Amphiphilic peptide compounds comprising one or more epitope sequences for binding interaction with one or more corresponding growth factors, micellar assemblies of such compounds and related methods of use.

Self-assembling peptide amphiphiles and related methods for growth factor delivery

DOEpatents

Stupp, Samuel I; Donners, Jack J.J.M.; Silva, Gabriel A; Behanna, Heather A; Anthony, Shawn G

2013-11-12

Amphiphilic peptide compounds comprising one or more epitope sequences for binding interaction with one or more corresponding growth factors, micellar assemblies of such compounds and related methods of use.

H2, He, and CO2 line-broadening coefficients, pressure shifts and temperature-dependence exponents for the HITRAN database. Part 1: SO2, NH3, HF, HCl, OCS and C2H2

NASA Astrophysics Data System (ADS)

Wilzewski, Jonas S.; Gordon, Iouli E.; Kochanov, Roman V.; Hill, Christian; Rothman, Laurence S.

2016-01-01

To increase the potential for use of the HITRAN database in astronomy, experimental and theoretical line-broadening coefficients, line shifts and temperature-dependence exponents of molecules of planetary interest broadened by H2, He, and CO2 have been assembled from available peer-reviewed sources. The collected data were used to create semi-empirical models so that every HITRAN line of the studied molecules has corresponding parameters. Since H2 and He are major constituents in the atmospheres of gas giants, and CO2 predominates in atmospheres of some rocky planets with volcanic activity, these spectroscopic data are important for remote sensing studies of planetary atmospheres. In this paper we make the first step in assembling complete sets of these parameters, thereby creating datasets for SO2, NH3, HF, HCl, OCS and C2H2.

Wide Field and Planetary Camera for Space Telescope

NASA Technical Reports Server (NTRS)

Lockhart, R. F.

1982-01-01

The Space Telescope's Wide Field and Planetary Camera instrument, presently under construction, will be used to map the observable universe and to study the outer planets. It will be able to see 1000 times farther than any previously employed instrument. The Wide Field system will be located in a radial bay, receiving its signals via a pick-off mirror centered on the optical axis of the telescope assembly. The external thermal radiator employed by the instrument for cooling will be part of the exterior surface of the Space Telescope. In addition to having a larger (1200-12,000 A) wavelength range than any of the other Space Telescope instruments, its data rate, at 1 Mb/sec, exceeds that of the other instruments. Attention is given to the operating modes and projected performance levels of the Wide Field Camera and Planetary Camera.

Semiconductor nanocrystals covalently bound to solid inorganic surfaces using self-assembled monolayers

DOEpatents

Alivisatos, A. Paul; Colvin, Vicki L.

1998-01-01

Methods are described for attaching semiconductor nanocrystals to solid inorganic surfaces, using self-assembled bifunctional organic monolayers as bridge compounds. Two different techniques are presented. One relies on the formation of self-assembled monolayers on these surfaces. When exposed to solutions of nanocrystals, these bridge compounds bind the crystals and anchor them to the surface. The second technique attaches nanocrystals already coated with bridge compounds to the surfaces. Analyses indicate the presence of quantum confined clusters on the surfaces at the nanolayer level. These materials allow electron spectroscopies to be completed on condensed phase clusters, and represent a first step towards synthesis of an organized assembly of clusters. These new products are also disclosed.

Meteoric Material: An Important Component of Planetary Atmospheres

NASA Technical Reports Server (NTRS)

Grebowsky, Joseph M.; Moses, Julianne I.; Pesnell, W. Dean; Vondrak, Richard R. (Technical Monitor)

2001-01-01

Interplanetary dust particles (IDPs) interact with all planetary atmospheres and leave their imprint as perturbations of the background atmospheric chemistry and structure. They lead to layers of metal ions that can become the dominant positively charged species in lower ionospheric regions. Theoretical models and radio occultation measurements provide compelling evidence that such layers exist in all planetary atmospheres. In addition IDP ablation products can affect neutral atmospheric chemistry, particularly at the outer planets where the IDPs supply oxygen compounds like water and carbon dioxide to the upper atmospheres. Aerosol or smoke particles from incomplete ablation or recondensation of ablated IDP vapors may also have a significant impact on atmospheric properties.

A Compact Instrument for Remote Raman and Fluorescence Measurements to a Radial Distance of 100 m

NASA Technical Reports Server (NTRS)

Sharma, S. K.; Misra, A. K.; Lucey, P. g.; McKay, C. P.

2005-01-01

Compact remote spectroscopic instruments that could provide detailed information about mineralogy, organic and biomaterials on a planetary surface over a relatively large area are desirable for NASA s planetary exploration program. Ability to explore a large area on the planetary surfaces as well as in impact craters from a fixed location of a rover or lander will enhance the probability of selecting target rocks of high scientific contents as well as desirable sites in search of organic compounds and biomarkers on Mars and other planetary bodies. We have developed a combined remote inelastic scattering (Raman) and laser-induced fluorescence emission (LIFE) compact instrument capable of providing accurate information about minerals, organic and biogenic materials to a radial distance of 100 m. Here we present the Raman and LIFE (R-LIFE) data set.

Hierarchical self-assembly of a bow-shaped molecule bearing self-complementary hydrogen bonding sites into extended supramolecular assemblies.

PubMed

Ikeda, Masato; Nobori, Tadahito; Schmutz, Marc; Lehn, Jean-Marie

2005-01-07

The bow-shaped molecule 1 bearing a self-complementary DAAD-ADDA (D=donor A=acceptor) hydrogen-bonding array generates, in hydrocarbon solvents, highly ordered supramolecular sheet aggregates that subsequently give rise to gels by formation of an entangled network. The process of hierarchical self-assembly of compound 1 was investigated by the concentration and temperature dependence of UV-visible and (1)H NMR spectra, fluorescence spectra, and electron microscopy data. The temperature dependence of the UV-visible spectra indicates a highly cooperative process for the self-assembly of compound 1 in decaline. The electron micrograph of the decaline solution of compound 1 (1.0 mM) revealed supramolecular sheet aggregates forming an entangled network. The selected area electronic diffraction patterns of the supramolecular sheet aggregates were typical for single crystals, indicative of a highly ordered assembly. The results exemplify the generation, by hierarchical self-assembly, of highly organized supramolecular materials presenting novel collective properties at each level of organization.

Self-assembly of nanocomposite materials

DOEpatents

Brinker, C. Jeffrey; Sellinger, Alan; Lu, Yunfeng

2001-01-01

A method of making a nanocomposite self-assembly is provided where at least one hydrophilic compound, at least one hydrophobic compound, and at least one amphiphilic surfactant are mixed in an aqueous solvent with the solvent subsequently evaporated to form a self-assembled liquid crystalline mesophase material. Upon polymerization of the hydrophilic and hydrophobic compounds, a robust nanocomposite self-assembled material is formed. Importantly, in the reaction mixture, the amphiphilic surfactant has an initial concentration below the critical micelle concentration to allow formation of the liquid-phase micellar mesophase material. A variety of nanocomposite structures can be formed, depending upon the solvent evaporazation process, including layered mesophases, tubular mesophases, and a hierarchical composite coating composed of an isotropic worm-like micellar overlayer bonded to an oriented, nanolaminated underlayer.

Semiconductor nanocrystals covalently bound to solid inorganic surfaces using self-assembled monolayers

DOEpatents

Alivisatos, A.P.; Colvin, V.L.

1998-05-12

Methods are described for attaching semiconductor nanocrystals to solid inorganic surfaces, using self-assembled bifunctional organic monolayers as bridge compounds. Two different techniques are presented. One relies on the formation of self-assembled monolayers on these surfaces. When exposed to solutions of nanocrystals, these bridge compounds bind the crystals and anchor them to the surface. The second technique attaches nanocrystals already coated with bridge compounds to the surfaces. Analyses indicate the presence of quantum confined clusters on the surfaces at the nanolayer level. These materials allow electron spectroscopies to be completed on condensed phase clusters, and represent a first step towards synthesis of an organized assembly of clusters. These new products are also disclosed. 10 figs.

Lunar and Planetary Science XXXV: Undergraduate Education and Research Programs, Facilities, and Information Access

NASA Technical Reports Server (NTRS)

2004-01-01

The titles in this section include: 1) GRIDVIEW: Recent Improvements in Research and Education Software for Exploring Mars Topography; 2) Software and Hardware Upgrades for the University of North Dakota Asteroid and Comet Internet Telescope (ACIT); 3) Web-based Program for Calculating Effects of an Earth Impact; 4) On-Line Education, Web- and Virtual-Classes in an Urban University: A Preliminary Overview; 5) Modelling Planetary Material's Structures: From Quasicrystalline Microstructure to Crystallographic Materials by Use of Mathematica; 6) How We Used NASA Lunar Set in Planetary and Material Science Studies: Textural and Cooling Sequences in Sections of Lava Column from a Thin and a Thick Lava-Flow, from the Moon and Mars with Terrestrial Analogue and Chondrule Textural Comparisons; 7) Classroom Teaching of Space Technology and Simulations by the Husar Rover Model; 8) New Experiments (In Meteorology, Aerosols, Soil Moisture and Ice) on the New Hunveyor Educational Planetary Landers of Universities and Colleges in Hungary; 9) Teaching Planetary GIS by Constructing Its Model for the Test Terrain of the Hunveyor and Husar; 10) Undergraduate Students: An Untapped Resource for Planetary Researchers; 11) Analog Sites in Field Work of Petrology: Rock Assembly Delivered to a Plain by Floods on Earth and Mars; 12) RELAB (Reflectance Experiment Laboratory): A NASA Multiuser Spectroscopy Facility; 13) Full Text Searching and Customization in the NASA ADS Abstract Service.

Design of the TMT Mid-Infrared Echelle: Science Drivers and Design Overview

DTIC Science & Technology

2006-01-01

plausibility of an extra-terrestrial origin for the prebiotic compounds that led to the emergence of life on Earth. MIRES imaging of debris disks will...explore mechanisms by which water and prebiotic organic compounds may have been delivered to planetary surfaces. These studies will be highly synergistic...that are precursors to complex prebiotic compounds. The high sensitivity also allows the exploration of a wider range of wavelengths, including those

Advanced engineering software for in-space assembly and manned planetary spacecraft

NASA Technical Reports Server (NTRS)

Delaquil, Donald; Mah, Robert

1990-01-01

Meeting the objectives of the Lunar/Mars initiative to establish safe and cost-effective extraterrestrial bases requires an integrated software/hardware approach to operational definitions and systems implementation. This paper begins this process by taking a 'software-first' approach to systems design, for implementing specific mission scenarios in the domains of in-space assembly and operations of the manned Mars spacecraft. The technological barriers facing implementation of robust operational systems within these two domains are discussed, and preliminary software requirements and architectures that resolve these barriers are provided.

A study of psychrophilic organisms isolated from the manufacture and assembly areas of spacecraft to be used in the Viking mission

NASA Technical Reports Server (NTRS)

Foster, T. L.; Winans, L., Jr.

1973-01-01

The sampling of soils from the manufacture and assembly areas of the Viking spacecraft is reported and the methodology employed in the analysis of these samples for psychrophilic microorganisms, and temperature studies on these organisms is outlined. Results showing the major types of organisms and the percentage of obligate psychrophiles in each sample are given and discussed. Emphasis in all areas is toward application of these results to the objectives of the planetary quarantine program.

Chromatographic instrumentation in space: past, present and future developments for exobiological studies

NASA Astrophysics Data System (ADS)

Raulin, F.; Sternberg, R.; Coscia, D.; Vidal-Madjar, C.; Millot, M.-C.; Sébille, B.; Israel, G.

1999-01-01

Several planetary exploration missions have already used chromatographic techniques to search for organic compounds, including complex organics, in extraterrestrial environments. So far, only gas chromatography (GC) has been used. In two cases (Viking and Cassini-Huygens), a Py-GC-MS instrument, coupling GC with a pyrolyzer and a mass spectrometer, has been flown. Powerful miniaturized Py-GC-MS instrumentation, with high resolution multi-GC columns and time-of-flight or Ion Trap mass spectrometers are under development, in the frame of the preparation of the Rosetta mission. There is now a strong need for new chromatographic instrumentation in space, in particular to perform detailed molecular analyses of complex non-volatile organics, including macromolecular compounds. Liquid Chromatography (LC), in particular High Performance Liquid Chromatography (HPLC) Supercritical Fluid Chromatography (SFC) or Chemical-Derivatization Gas Chromatography (CDGC) could provide a very efficient mean of analyzing a wide variety of exobiologically important compounds. LC or CDGC have never been used in space yet, but feasibility studies on their application in planetary mission are needed.

Geochemistry of Enceladus and the Galilean Moons from in situ Analysis of Ejecta

NASA Astrophysics Data System (ADS)

Postberg, F.; Schmidt, J.; Hillier, J. K.; Kempf, S.; Srama, R.

2012-09-01

The contribution of Cassini's dust detector CDA in revealing subsurface liquid water on Enceladus has demonstrated how questions in planetary science can be addressed by in situ analyses of icy dust particles. As the measurements are particularly sensitive to non-ice compounds embedded in an ice matrix, concentrations of various salts and organic compounds can be identified in different dust populations. This has successfully been demonstrated at Enceladus, giving insights in the moons subsurface geochemistry. This method can be applied to any planetary body that ejects particles to distances suitable for spacecraft sensing. The Galilean moons are of particular relevance since they are believed to steadily emit grains from their surfaces either by active volcanism (Io) or stimulated by micrometeoroid bombardment (Europa, Ganymede, Callisto).

Failure Simulation Testing of the Z-1 Spacesuit Titanium Bearing Assemblies

NASA Technical Reports Server (NTRS)

de Baca, Richard C.; Juarez, Alfredo; Peralta, Stephen; Tylka, Jonathan; Rhodes, Richard

2016-01-01

The Z-2 is a candidate for NASA's next generation spacesuit, designed for a range of possible missions with enhanced mobility for spacewalks both on planetary surfaces and in microgravity. Increased mobility was accomplished through innovations in shoulder and hip joints, using a number of new bearings to allow spacesuit wearers to dip, walk, and bend with ease; all important tasks for a planetary explorer collecting samples or traveling over rough terrain. The Advanced Spacesuit Development Team of NASA Johnson Space Center requested that the NASA White Sands Test Facility (WSTF) perform a series failure simulation tests on three titanium bearing assemblies, an elemental part of the joint construction used in new spacesuit designs. This testing simulated two undetected failures within the bearings and as a result the objective of this test program was to evaluate whether a failed or failing bearing could result in ignition of the titanium race material due to friction. The first failure was an inner seal leak sufficient to pressurize the race with +99 percent oxygen. The second failure was an improperly installed or mismatched ball port that created a protrusion in the ball bearing race, partially obstructing the nominal rolling path of each ball bearing. When the spacesuit bearings are assembled, bearing balls are loaded into the assembly via a ball port. The ball port is specific and unique to each bearing assembly (matched pair). The simulated mismatched ball port is a significant source of friction, which would be caused by an assembly error. To evaluate this risk, the bearings were cycled in a simulated worst-case scenario environment, with operational loads, and potential flaw conditions. During test the amount of actuation torque required and heat generated through continuous operation were measured and the bearings were observed for sparks or burning events. This paper provides detailed descriptions of the test hardware, methodology, and results.

Partition efficiencies of newly fabricated universal high-speed counter-current chromatograph for separation of two different types of sugar derivatives with organic-aqueous two-phase solvent systems.

PubMed

Shinomiya, Kazufusa; Sato, Kazuki; Yoshida, Kazunori; Tokura, Koji; Maruyama, Hiroshi; Yanagidaira, Kazuhiro; Ito, Yoichiro

2013-12-27

A new design of universal high-speed counter-current chromatograph (HSCCC) was fabricated in our laboratory. It holds a set of four column holders symmetrically around the rotary frame at a distance of 11.2cm from the central axis. By engaging the stationary gear on the central axis of the centrifuge to the planetary gears on the column holder shaft through a set of idle gears, two pairs of diagonally located column holders simultaneously rotate about their own axes in the opposite directions: one forward (type-J planetary motion) and the other backward (type-I planetary motion) each synchronously with the revolution. Using the eccentric coil assembly, partition efficiencies produced by these two planetary motions were compared on the separation of two different types of sugar derivatives (4-methylumbelliferyl and 5-bromo-4-chloro-3-indoxyl sugar derivatives) using organic-aqueous two-phase solvent systems composed of n-hexane/ethyl acetate/1-butanol/methanol/water and aqueous 0.1M sodium tetraborate, respectively. With lower phase mobile, better peak resolution was obtained by the type-J forward rotation for both samples probably due to higher retention of the stationary phase. With upper phase mobile, however, similar peak resolutions were obtained between these two planetary motions for both sugar derivatives. The overall results indicate that the present universal HSCCC is useful for counter-current chromatographic separation since each planetary motion has its specific applications: e.g., vortex CCC by the type-I planetary motion and HSCCC by the type-J planetary motion both for separation of various natural and synthetic products. Copyright © 2013 Elsevier B.V. All rights reserved.

Engineered human broncho-epithelial tissue-like assemblies

NASA Technical Reports Server (NTRS)

Goodwin, Thomas J. (Inventor)

2012-01-01

Three-dimensional human broncho-epithelial tissue-like assemblies (TLAs) are produced in a rotating wall vessel (RWV) with microcarriers by coculturing mesenchymal bronchial-tracheal cells (BTC) and bronchial epithelium cells (BEC). These TLAs display structural characteristics and express markers of in vivo respiratory epithelia. TLAs are useful for screening compounds active in lung tissues such as antiviral compounds, cystic fibrosis treatments, allergens, and cytotoxic compounds.

Mars ecopoiesis test bed: on earth and on the red planet

NASA Astrophysics Data System (ADS)

Todd, Paul; Kurk, Michael Andy; Boland, Eugene; Thomas, David; Scherzer, Christopher

2016-07-01

The concept of autotrophic organisms serving as planetary pioneers as a precursor to terraforming has been under consideration for several decades, and the term Ecopoiesis was introduced by the ecopoiets C. Sagan, M. Avener, R. Haynes and C. McKay to call attention to this possibility. There is a continuing need for experimental evidence to support this concept, one of them being the need to evaluate the survivability of terrestrial autotrophic microbes in a planetary environment. For this and other purposes a planetary simulation facility was constructed and operated at Techshot, Inc. in Indiana, USA. This facility has an accumulated record of more than one year's worth of experimentation under simulated Mars conditions. In a recent study this facility was operated for five weeks in a mode that simulated 35 sols on and just below the surface of Mars at low latitude. The diurnal lighting period was 12 hours:12 hours using xenon arc light filtered to simulate the solar intensity and spectrum on the Martian surface. A daily temperature profile followed that recorded at low latitudes with night-time minima at -80 C and noontime maxima at +26 C. Atmosphere was CO _{2} at <11 mbar. Moisture was monitored to confirm that no water could exist in the liquid phase. Test organisms included the cyanobacteria Anabena, sp., Chroococcidiopsis CCMEE171 and Plectonema boryanum and Eukaryota: Chlorella ellipsoidia maintained in the simulator under the above-described conditions. The exposed specimens were tested for intracellular esterase activity, chlorophyll content and reproductive survival. All tests yielded low-level positive survival results for these organisms. No definitive data relating to function and/or growth during exposure were sought. In parallel to these terrestrial studies a planned design study was undertaken for a proposed test bed to be operated on the surface of Mars. Design requirements include compact assembly for transport and installation on the planetary surface (multiple units per mission would be expected), protective internal package for the release of organisms, a means of atmosphere exchange, access to sunlight, a means of penetrating the planetary surface, and most importantly a means of acquiring regolith while meeting requirements of planetary protection. An enlarged-scale mock-up of this design was fabricated by additive manufacturing with moving parts that simulate the components of the design. This mock-up assembly marks a starting point for a planetary surface probe for safe implantation on the surface of the Red Planet some decades in the future. This research was supported by NASA NIAC Phase I Grant "Mars Ecopoiesis Testbed" NNX14AM97G.

Utilization of Low-Pressure Plasma to Inactivate Bacterial Spores on Stainless Steel Screws

PubMed Central

Stapelmann, Katharina; Fiebrandt, Marcel; Raguse, Marina; Awakowicz, Peter; Reitz, Günther

2013-01-01

Abstract A special focus area of planetary protection is the monitoring, control, and reduction of microbial contaminations that are detected on spacecraft components and hardware during and after assembly. In this study, wild-type spores of Bacillus pumilus SAFR-032 (a persistent spacecraft assembly facility isolate) and the laboratory model organism B. subtilis 168 were used to study the effects of low-pressure plasma, with hydrogen alone and in combination with oxygen and evaporated hydrogen peroxide as a process gas, on spore survival, which was determined by a colony formation assay. Spores of B. pumilus SAFR-032 and B. subtilis 168 were deposited with an aseptic technique onto the surface of stainless steel screws to simulate a spore-contaminated spacecraft hardware component, and were subsequently exposed to different plasmas and hydrogen peroxide conditions in a very high frequency capacitively coupled plasma reactor (VHF-CCP) to reduce the spore burden. Spores of the spacecraft isolate B. pumilus SAFR-032 were significantly more resistant to plasma treatment than spores of B. subtilis 168. The use of low-pressure plasma with an additional treatment of evaporated hydrogen peroxide also led to an enhanced spore inactivation that surpassed either single treatment when applied alone, which indicates the potential application of this method as a fast and suitable way to reduce spore-contaminated spacecraft hardware components for planetary protection purposes. Key Words: Bacillus spores—Contamination—Spacecraft hardware—Plasma sterilization—Planetary protection. Astrobiology 13, 597–606. PMID:23768085

Integrated Lens Antennas for Multi-Pixel Receivers

NASA Technical Reports Server (NTRS)

Lee, Choonsup; Chattopadhyay, Goutam

2011-01-01

Future astrophysics and planetary experiments are expected to require large focal plane arrays with thousands of detectors. Feedhorns have excellent performance, but their mass, size, fabrication challenges, and expense become prohibitive for very large focal plane arrays. Most planar antenna designs produce broad beam patterns, and therefore require additional elements for efficient coupling to the telescope optics, such as substrate lenses or micromachined horns. An antenna array with integrated silicon microlenses that can be fabricated photolithographically effectively addresses these issues. This approach eliminates manual assembly of arrays of lenses and reduces assembly errors and tolerances. Moreover, an antenna array without metallic horns will reduce mass of any planetary instrument significantly. The design has a monolithic array of lens-coupled, leaky-wave antennas operating in the millimeter- and submillimeter-wave frequencies. Electromagnetic simulations show that the electromagnetic fields in such lens-coupled antennas are mostly confined in approximately 12 15 . This means that one needs to design a small-angle sector lens that is much easier to fabricate using standard lithographic techniques, instead of a full hyper-hemispherical lens. Moreover, this small-angle sector lens can be easily integrated with the antennas in an array for multi-pixel imager and receiver implementation. The leaky antenna is designed using double-slot irises and fed with TE10 waveguide mode. The lens implementation starts with a silicon substrate. Photoresist with appropriate thickness (optimized for the lens size) is spun on the substrate and then reflowed to get the desired lens structure. An antenna array integrated with individual lenses for higher directivity and excellent beam profile will go a long way in realizing multi-pixel arrays and imagers. This technology will enable a new generation of compact, low-mass, and highly efficient antenna arrays for use in multi-pixel receivers and imagers for future planetary and astronomical instruments. These antenna arrays can also be used in radars and imagers for contraband detection at stand-off distances. This will be enabling technology for future balloon-borne, smaller explorer class mission (SMEX), and other missions, and for a wide range of proposed planetary sounders and radars for planetary bodies.

Pulsed Laser Techniques to Determine Lattice and Radiative Thermal Conductivity of Deep Planetary Materials at Extreme Pressure-Temperature Conditions

NASA Astrophysics Data System (ADS)

Lobanov, S.; Goncharov, A. F.; Holtgrewe, N.; Konopkova, Z.; McWilliams, R. S.

2017-12-01

Thermal conductivity of deep planetary materials determines the planetary heat transport mode and properties (e.g. magnetic field) and can be used to decipher the planetary thermal history. Due to the lack of direct measurements of the lattice and radiative conductivity of the relevant materials at the planetary conditions, the current geodynamical models use theoretical calculations and extrapolations of the available experimental data. Here we describe our pulsed laser techniques that enable direct measurements of the lattice and radiative lattice conductivity of the Earth's mantle and core materials and also of noble gases and simple molecules present in the interiors of giant planets (e.g. hydrogen). Flash heating laser techniques working in a pump-probe mode that include time resolved two-side radiative and thermoreflection temperature probes employ various laser and photo-detector configurations, which provide a measure of the thermal fluxes propagating through the samples confined in the diamond anvil cell cavity. A supercontinuum ultra-bright broadband laser source empower accurate measurements of the optical properties of planetary materials used to extract the radiative conductivity. Finite element calculations serve to extract the temperature and pressure dependent thermal conductivity and temperature gradients across the sample. We report thermal conductivity measurements of the Earth's minerals (postperovskite, bridgmanite, ferropericlase) and their assemblies (pyrolite) and core materials (Fe and alloys with Si and O) at the realistic deep Earth's pressure temperature conditions. We thank J.-F.Lin, M. Murakami, J. Badro for contributing to this work.

Next-Generation MKIII Lightweight HUT/Hatch Assembly

NASA Technical Reports Server (NTRS)

McCarthy, Mike; Toscano, Ralph

2013-01-01

The MK III (H-1) carbon-graphite/ epoxy Hard Upper Torso (HUT)/Hatch assembly was designed, fabricated, and tested in the early 1990s. The spacesuit represented an 8.3 psi (˜58 kPa) technology demonstrator model of a zero prebreathe suit. The basic torso shell, brief, and hip areas of the suit were composed of a carbon-graphite/epoxy composite lay-up. In its current configuration, the suit weighs approximately 120 lb (˜54 kg). However, since future planetary suits will be designed to operate at 0.26 bar (˜26 kPa), it was felt that the suit's re-designed weight could be reduced to 79 lb (˜35 kg) with the incorporation of lightweight structural materials. Many robust, lightweight structures based on the technologies of advanced honeycomb materials, revolutionary new composite laminates, metal matrix composites, and recent breakthroughs in fullerene fillers and nanotechnology lend themselves well to applications requiring materials that are both light and strong. The major problem involves the reduction in weight of the HUT/ Hatch assembly for use in lunar and/or planetary applications, while at the same time maintaining a robust structural design. The technical objective is to research, design, and develop manufacturing methods that support fa b rica - tion of a lightweight HUT/Hatch assembly using advanced material and geometric redesign as necessary. Additionally, the lightweight HUT/Hatch assembly will interface directly with current MK III hardware. Using the new operating pressure and current MK III (H-1) interfaces as a starting block, it is planned to maximize HUT/Hatch assembly weight reduction through material selection and geometric redesign. A hard upper torso shell structure with rear-entry closure and corresponding hatch will be fabricated. The lightweight HUT/Hatch assembly will retrofit and interface with existing MK III (H-1) hardware elements, providing NASA with immediate "plug-andplay" capability. NASA crewmembers will have a lightweight, robust, life-support system that will minimize fatigue during extraterrestrial surface sojourns. Its unique feature is the utilization of a new and innovative family of materials used by the aerospace industry, which at the time of this reporting has not been used for the proposed application.

Classification of coordination polygons and polyhedra according to their mode of self-assembly.

PubMed

Swiegers, G F; Malefetse, T J

2001-09-03

This work extends techniques for the controlled formation of synthetic molecular containers by metal-mediated self-assembly. A new classification system based on the self-assembly of such species is proposed. The system: 1) allows a systematic identification of suitable acceptor-donor combinations, 2) widens the variety of design possibilities available, 3) allows a ready comparison of the self-assembly of different compounds, 4) reveals useful commonalities between different compounds, 5) aids in the development of novel architectures, and 6) permits identification of systems capable of being switched back-and-forth between architectures.

Report of the December 2009 Titan Planetary Protection workshop

NASA Astrophysics Data System (ADS)

Raulin, Francois; Rummel, John; Kminek, Gerhard; Conley, Catharine; Ehrenfreund, Pascale

The status of planning for space missions to explore the outer solar system has identified the need to define the proper planetary protection categories and implementation guidelines for outer planet satellites. A COSPAR planetary protection workshop was held in Vienna in April 2009 on that subject, and a consensus was found regarding the planetary protection status of many of these objects. However, it was determined that for the planetary protection categorization of Titan further data and studies were required, to conclude whether there is only a remote (Cat. II) or significant (Cat. III) chance that contamination carried by a spacecraft could jeopardize future exploration. The main issue to be resolved is the uncertainty surrounding the communication between the surface and the potentially liquid water in the subsurface with regard to (feasible) processes and associated time frames. It was thus decided to have a planetary protection workshop fully dedicated to the case of Titan, both to focus greater expertise on the subject and to make use of additional Cassini-Huygens mission data. A two days Titan Planetary Protection workshop was thus organized at Caltech, on December 9 and 10, 2009. The meeting was sponsored by NASA and ESA, with the participation of the COSPAR Panel on Planetary Protection. It was attended by 25 participants. The goal of this workshop was to resolve the mission category for Titan (and Ganymede) and develop a consensus on the Category II (remote chance that contamination jeopardize future exploration) versus II+ /III (less remote or significant chance of contamination jeopardize future exploration) dichotomy, taking into account both the conservative nature of planetary protection policy and the physical constraints on the Titan and Ganymede systems. The outcome of this workshop will be presented and discussed during the PPP1 session of the COSPAR General Assembly meeting in Bremen. Note: all participants of the Titan PP workshop are associated to this presentation.

Hydrogen atom initiated chemistry. [chemical evolution in planetary atmospheres

NASA Technical Reports Server (NTRS)

Hong, J. H.; Becker, R. S.

1979-01-01

H Atoms have been created by the photolysis of H2S. These then initiated reactions in mixtures involving acetylene-ammonia-water and ethylene-ammonia-water. In the case of the acetylene system, the products consisted of two amino acids, ethylene and a group of primarily cyclic thio-compounds, but no free sulfur. In the case of the ethylene systems, seven amino acids, including an aromatic one, ethane, free sulfur, and a group of solely linear thio-compounds were produced. Total quantum yields for the production of amino acids were about 3 x 10 to the -5th and about 2 x 10 to the -4th with ethylene and acetylene respectively as carbon substrates. Consideration is given of the mechanism for the formation of some of the products and implications regarding planetary atmosphere chemistry, particularly that of Jupiter, are explored.

Report on the COSPAR Workshop on Refining Planetary Protection Requirements for Human Missions

NASA Astrophysics Data System (ADS)

Spry, James Andrew; Rummel, John; Conley, Catharine; Race, Margaret; Kminek, Gerhard; Siegel, Bette

2016-07-01

A human mission to Mars has been the driving long-term goal for the development of the Global Exploration Roadmap by the International Space Exploration Coordination Group. Additionally, multiple national space agencies and commercial organizations have published similar plans and aspirations for human missions beyond LEO. The current COSPAR planetary protection "Guidelines for Human Missions to Mars" were developed in a series of workshops in the early 2000s and adopted into COSPAR policy at the Montreal Assembly in 2008. With changes and maturation in mission architecture concepts and hardware capabilities, the holding of a workshop provided an opportunity for timely review of these guidelines and their interpretation within current frameworks provided by ISECG and others. The COSPAR Workshop on Refining Planetary Protection Requirements for Human Missions was held in the US in spring 2016 to evaluate recent efforts and activities in the context of current COSPAR policy, as well as collect inputs from the various organizations considering crewed exploration missions to Mars and precursor robotic missions focused on surface material properties and environmental challenges. The workshop also considered potential updates to the COSPAR policy for human missions across a range of planetary destinations. This paper will report on those deliberations.

A Planetary Protection Strategy for the Mars Aerial Regional-Scale Environmental Survey (ARES) Mission Concept

NASA Technical Reports Server (NTRS)

Kuhl, Christopher A.

2008-01-01

The Aerial Regional-scale Environmental Survey (ARES) is a Mars exploration mission concept designed to send an airplane to fly through the lower atmosphere of Mars, with the goal of taking scientific measurements of the atmosphere, surface, and subsurface phenomenon. ARES was first proposed to the Mars Scout program in December 2002 for a 2007 launch opportunity and was selected to proceed with a Phase A study, step-2 proposal which was submitted in May 2003. ARES was not selected for the Scout mission, but efforts continued on risk reduction of the atmospheric flight system in preparation for the next Mars Scout opportunity in 2006. The ARES concept was again proposed in July 2006 to the Mars Scout program but was not selected to proceed into Phase A. This document describes the Planetary Protection strategy that was developed in ARES Pre Phase-A activities to help identify, early in the design process, certain hardware, assemblies, and/or subsystems that will require unique design considerations based on constraints imposed by Planetary Protection requirements. Had ARES been selected as an exploration project, information in this document would make up the ARES Project Planetary Protection Plan.

An Undergraduate Endeavor: Assembling a Live Planetarium Show About Mars

NASA Astrophysics Data System (ADS)

McGraw, Allison M.

2016-10-01

Viewing the mysterious red planet Mars goes back thousands of years with just the human eye but in more recent years the growth of telescopes, satellites and lander missions unveil unrivaled detail of the Martian surface that tells a story worth listening to. This planetarium show will go through the observations starting with the ancients to current understandings of the Martian surface, atmosphere and inner-workings through past and current Mars missions. Visual animations of its planetary motions, display of high resolution images from the Hi-RISE (High Resolution Imaging Science Experiment) and CTX (Context Camera) data imagery aboard the MRO (Mars Reconnaissance Orbiter) as well as other datasets will be used to display the terrain detail and imagery of the planet Mars with a digital projection system. Local planetary scientists and Mars specialists from the Lunar and Planetary Lab at the University of Arizona (Tucson, AZ) will be interviewed and used in the show to highlight current technology and understandings of the red planet. This is an undergraduate project that is looking for collaborations and insight in order gain structure in script writing that will teach about this planetary body to all ages in the format of a live planetarium show.

Required Equipment for Photo-Switchable Donor-Acceptor (D-A) Dyad Interfacial Self-Assembled Monolayers for Organic Photovoltaic Cells

DTIC Science & Technology

2014-01-24

Interfacial Tuning via Electron-Blocking/Hole-Transport Layers and Indium Tin Oxide Surface Treatment in Bulk- Heterojunction Organic Photovoltaic Cells...devices Figure 3 shows the compounds we prepared to assemble on gold (Au) surfaces. Results of TPA-C60 dyads (1 and 2) self-assembled on Au electrodes...surface hydroxyl groups, respectively, we decided to prepare compounds 5-7 to attach as SAMs, see Figure 5. Difficulties and unexpected problems

Results from the Science Instrument Definition Team for the Gondola for High Altitude Planetary Science Project

NASA Astrophysics Data System (ADS)

Chanover, Nancy J.; Aslam, Shahid; DiSanti, Michael A.; Hibbitts, Charles A.; Honniball, Casey I.; Paganini, Lucas; Parker, Alex; Skrutskie, Michael F.; Young, Eliot F.

2016-10-01

The Gondola for High Altitude Planetary Science (GHAPS) is an observing asset under development by NASA's Planetary Science Division that will be hosted on stratospheric balloon missions intended for use by the broad planetary science community. GHAPS is being designed in a modular fashion to interface to a suite of instruments as called for by science needs. It will operate at an altitude of 30+ km and will include an optical telescope assembly with a 1-meter aperture and a pointing stability of approximately 1 arcsecond with a flight duration of ~100 days. The spectral grasp of the system is envisaged to include wavelengths spanning the near-ultraviolet to near/mid-infrared (~0.3-5 µm) and possibly to longer wavelengths.The GHAPS Science Instrument Definition Team (SIDT) was convened in May 2016 to define the scope of science investigations, derive the science requirements and instrument concepts for GHAPS, prioritize the instruments according to science priorities that address Planetary Science Decadal Survey questions, and generate a report that is broadly disseminated to the planetary science community. The SIDT examined a wide range of solar system targets and science questions, focusing on unique measurements that could be made from a balloon-borne platform to address high-priority planetary science questions for a fraction of the cost of space missions. The resulting instrument concepts reflect unique capabilities offered by a balloon-borne platform (e.g., observations at spectral regions inaccessible from the ground due to telluric absorption, diffraction-limited imaging, and long duration uninterrupted observations of a target). We discuss example science cases that can be addressed with GHAPS and describe a notional instrument suite that can be used by guest observers to pursue decadal-level science questions.

U.S. National Report to International Union of Geodesy and Geophysics 1987-1990; Proceedings of the IUGG General Assembly, 20th, Vienna, Austria, Aug. 11-24, 1991

NASA Technical Reports Server (NTRS)

Shea, Margaret A. (Editor)

1991-01-01

An authoritative record of contributions of geophysical research in the U.S. during 1987-1990 is reported. Major areas of research include atmospheric sciences, geodesy, hydrology, planetology, geomagnetism, paleomagnetism, volcanology, geochemistry, petrology, oceanography, seismology, tectonophysics, and solar-planetary relations.

Automated Design of Multiphase Space Missions Using Hybrid Optimal Control

ERIC Educational Resources Information Center

Chilan, Christian Miguel

2009-01-01

A modern space mission is assembled from multiple phases or events such as impulsive maneuvers, coast arcs, thrust arcs and planetary flybys. Traditionally, a mission planner would resort to intuition and experience to develop a sequence of events for the multiphase mission and to find the space trajectory that minimizes propellant use by solving…

Formation and Characterization of Likely Pseudo-Biomarkers in Extraterrestrial Samples

NASA Astrophysics Data System (ADS)

Benstein, M. P.; Dworkin, J.; Mattioda, A.; Hudgins, D.; Sandford, S.; Allamandola, L.; Cooper, G.; Elsila, J.; Zare, R.; Ashbourn, S.; Iraci, L.

2002-12-01

Over the next several years there will be numerous missions (e.g. Cassini, Rosetta, Mars NetLander) to explore Mars, Europa, Titan, and other bodies. One of most interesting objectives of these probes in the search for chemical evidence of extant or extinct life. Chemical evidence of life is currently defined as presence of members of a list of compounds-biomarkers-which are thought to be produced primarily by biology. This approach has been very instructive in the study of Terrestrial organisms, either ancient, lithic, or extremophile. However the compounds studied in extraterrestial samples, be they meteorites, returned samples, or material measured robotically, should be examined for contamination by pseudobiomarkers from abiotic processes. One should be particularly careful of compounds for which extraterrestrial or extrasolar abiotic syntheses have been demonstrated (i.e. Bernstein, et al. 2002. Racemic amino acids from the ultraviolet photolysis of interstellar ice analogues. Nature 416, 401, Dworkin, et al. (2001). Self-Assembling Amphiphilic Molecules: Synthesis in Simulated Interstellar/Precometary Ices. Proc. Nat. Acad. Sci. 98, 815, and Bernstein, et al. 2001. Ultraviolet Irradiation of Naphthalene in H2O Ice: Implications for Meteorites and Biogenesis. Meteoritics and Planetary Science, 36, 351). The Astrochemistry Laboratory at NASA Ames (astrochem.org) has been studying a variety of compounds which should be readily synthesized abiotically (via energetic processing) in the icy mantles around dust grains. These icy-grains are abundant in the Galaxy and are a feed-stock for the formation of planets and other bodies. Thus, it is likely that the compounds synthesized on grains were not only delivered to the early Earth, but are still being delivered to the modern Earth as well as to planets and moons of exobiological interest. Here we will present our detection of amphiphiles, amino acids, quinones, nitrogen heterocycles, and numerous functionalized aromatics in laboratory simulations of interstellar ices. These compounds are so readily synthesized from plausible and ubiquitous ices, that their detection samples of extraterrestrial origin is unlikely to be of biological origin. We will also discuss the limitations of biological interpretations of UV/visible and infrared spectroscopy in evaluating the presence of biomolecules.

The role of phosphorus in chemical evolution.

PubMed

Maciá, Enrique

2005-08-01

In this tutorial review we consider the role of phosphorus and its compounds within the context of chemical evolution in galaxies. Following an interdisciplinary approach we first discuss the position of P among the main biogenic elements by considering its relevance in most essential biochemical functions as well as its peculiar chemistry under different physicochemical conditions. Then we review the phosphorus distribution in different cosmic sites, such as terrestrial planets, interplanetary dust particles, cometary dust, planetary atmospheres and the interstellar medium (ISM). In this way we realize that this element is both scarce and ubiquitous in the universe. These features can be related to the complex nucleosynthesis of P nuclide in the cores of massive stars under explosive conditions favouring a wide distribution of this element through the ISM, where it would be ready to react with other available atoms. A general tendency towards more oxidized phosphorus compounds is clearly appreciated as chemical evolution proceeds from circumstellar and ISM materials to protoplanetary and planetary condensed matter phases. To conclude we discuss some possible routes allowing for the incorporation of phosphorus compounds of prebiotic interest during the earlier stages of solar system formation.

Planetary Protection Concerns During Pre-Launch Radioisotope Power System Final Integration Activities

NASA Technical Reports Server (NTRS)

Chen, Fei; McKay, Terri; Spry, James A.; Colozza, Anthony J.; DiStefano, Salvador

2012-01-01

The Advanced Stirling Radioisotope Generator (ASRG) is a next-generation radioisotope-based power system that is currently being developed as an alternative to the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG). Power sources such as these may be needed for proposed missions to solar system planets and bodies that have challenging Planetary Protection (PP) requirements (e.g. Mars, Europa, Enceladus) that may support NASA s search for life, remnants of past life, and the precursors of life. One concern is that the heat from the ASRG could potentially create a region in which liquid water may occur. As advised by the NASA Planetary Protection Officer, when deploying an ASRG to Mars, the current COSPAR/NASA PP policy should be followed for Category IVc mission. Thus, sterilization processing of the ASRG to achieve bioburden reduction would be essential to meet the Planetary Protection requirements. Due to thermal constraints and associated low temperature limits of elements of the ASRG, vapor hydrogen peroxide (VHP) was suggested as a candidate alternative sterilization process to complement dry heat microbial reduction (DHMR) for the assembled ASRG. The following proposed sterilization plan for the ASRG anticipates a mission Category IVc level of cleanliness. This plan provides a scenario in which VHP is used as the final sterilization process. Keywords: Advanced Stirling Radioisotope Generator (ASRG), Planetary Protection (PP), Vapor hydrogen peroxide (VHP) sterilization.

Teaching, learning, and planetary exploration

NASA Technical Reports Server (NTRS)

Brown, Robert A.

1992-01-01

The progress accomplished in the first five months of the three-year grant period of Teaching, Learning, and Planetary Exploration is presented. The objectives of this project are to discover new education products and services based on space science, particularly planetary exploration. An Exploration in Education is the umbrella name for the education projects as they are seen by teachers and the interested public. As described in the proposal, our approach consists of: (1) increasing practical understanding of the potential role and capabilities of the research community to contribute to basic education using new discoveries; (2) developing an intellectual framework for these contributions by supplying criteria and templates for the teacher's stories; (3) attracting astronomers, engineers, and technical staff to the project and helping them form productive education partnerships for the future, (4) exploring relevant technologies and networks for authoring and communicating the teacher's stories; (5) enlisting the participation of potential user's of the teacher's stories in defining the products; (6) actually producing and delivering many educationally useful teacher's stories; and (7) reporting the pilot study results with critical evaluation. Technical progress was made by assembling our electronic publishing stations, designing electronic publications based on space science, and developing distribution approaches for electronic products. Progress was made addressing critical issues by developing policies and procedures for securing intellectual property rights and assembling a focus group of teachers to test our ideas and assure the quality of our products. The following useful materials are being produced: the TOPS report; three electronic 'PictureBooks'; one 'ElectronicArticle'; three 'ElectronicReports'; ten 'PrinterPosters'; and the 'FaxForum' with an initial complement of printed materials. We have coordinated with planetary scientists and astronomers both at the technical and policy level to assure the efficiency and ultimate utility of these efforts to derive educational benefits from the space science and exploration program as a whole.

Science with the James Webb Space Telescope

NASA Technical Reports Server (NTRS)

Gardner, Jonathan P.

2006-01-01

The scientific capabilities of the James Webb Space Telescope (JWST) fall into four themes. The End of the Dark Ages: First Light and Reionization theme seeks to identify the first luminous sources to form and to determine the ionization history of the universe. The Assembly of Galaxies theme seeks to determine how galaxies and the dark matter, gas, stars, metals, morphological structures, and active nuclei within them evolved from the epoch of reionization to the present. The Birth of Stars and Protoplanetary Systems theme seeks to unravel the birth and early evolution of stars, from infall onto dustenshrouded protostars, to the genesis of planetary systems. Planetary Systems and the Origins of Life theme seeks to determine the physical and chemical properties of planetary systems around nearby stars and of our own, and investigate the potential for life in those systems. To enable these for science themes, JWST will be a large (6.5m) cold (50K) telescope with four instruments, capable of imaging and spectroscopy from 0.6 to 27 microns wavelength.

Adaptation of a Filter Assembly to Assess Microbial Bioburden of Pressurant Within a Propulsion System

NASA Technical Reports Server (NTRS)

Benardini, James N.; Koukol, Robert C.; Schubert, Wayne W.; Morales, Fabian; Klatte, Marlin F.

2012-01-01

A report describes an adaptation of a filter assembly to enable it to be used to filter out microorganisms from a propulsion system. The filter assembly has previously been used for particulates greater than 2 micrometers. Projects that utilize large volumes of nonmetallic materials of planetary protection concern pose a challenge to their bioburden budget, as a conservative specification value of 30 spores per cubic centimeter is typically used. Helium was collected utilizing an adapted filtration approach employing an existing Millipore filter assembly apparatus used by the propulsion team for particulate analysis. The filter holder on the assembly has a 47-mm diameter, and typically a 1.2-5 micrometer pore-size filter is used for particulate analysis making it compatible with commercially available sterilization filters (0.22 micrometers) that are necessary for biological sampling. This adaptation to an existing technology provides a proof-of-concept and a demonstration of successful use in a ground equipment system. This adaptation has demonstrated that the Millipore filter assembly can be utilized to filter out microorganisms from a propulsion system, whereas in previous uses the filter assembly was utilized for particulates greater than 2 micrometers.

MOMA and other next-generation ion trap mass spectrometers for planetary exploration

NASA Astrophysics Data System (ADS)

Arevalo, R. D., Jr.; Brinckerhoff, W. B.; Getty, S.; Mahaffy, P. R.; van Amerom, F. H. W.; Danell, R.; Pinnick, V. T.; Li, X.; Grubisic, A.; Southard, A. E.; Hovmand, L.; Cottin, H.; Makarov, A.

2016-12-01

Since the 1970's, quadrupole mass spectrometer (QMS) systems have served as low-risk, cost-efficient means to explore the inner and outer reaches of the solar system. These legacy instruments have interrogated the compositions of the lunar exosphere (LADEE), surface materials on Mars (MSL), and the atmospheres of Venus (Pioneer Venus), Mars (MAVEN) and outer planets (Galileo and Cassini-Huygens). However, the in situ detection of organic compounds on Mars and Titan, coupled with ground-based measurements of amino acids in meteorites and a variety of organics in comets, has underlined the importance of molecular disambiguation in the characterization of high-priority planetary environments. The Mars Organic Molecule Analyzer (MOMA) flight instrument, centered on a linear ion trap, enables the in situ detection of volatile and non-volatile organics, but also the characterization of molecular structures through SWIFT ion isolation/excitation and tandem mass spectrometry (MSn). Like the SAM instrument on MSL, the MOMA investigation also includes a gas chromatograph (GC), thereby enabling the chemical separation of potential isobaric interferences based on retention times. The Linear Ion Trap Mass Spectrometer (LITMS; PI: William Brinckerhoff), developed to TRL 6 via the ROSES MatISSE Program, augments the core MOMA design and adds: expanded mass range (from 20 - 2000 Da); high-temperature evolved gas analysis (up to 1300°C); and, dual polarity detector assemblies (supporting the measurement of negative ions). The LITMS instrument will be tested in the field in 2017 through the Atacama Rover Astrobiology Drilling Studies (ARADS; PI: Brian Glass) ROSES PSTAR award. Following on these advancements, the Advanced Resolution Organic Molecule Analyzer (AROMA; PI: Ricardo Arevalo Jr.), supported through the ROSES PICASSO Program, combines a highly capable MOMA/LITMS-like linear ion trap and the ultrahigh resolution CosmOrbitrap mass analyzer developed by a consortium of five French laboratories. Phase I of this project has seen the development of a dedicated testbed that enables performance characterization of an Orbitrap analyzer as a function of compromised environmental conditions, simulating the reduced resources expected for planetary missions to small bodies and/or cryogenic worlds.

Sample Analysis at Mars for Curiosity

NASA Image and Video Library

2010-10-08

The Sample Analysis at Mars SAM instrument will analyze samples of Martian rock and soil collected by the rover arm to assess carbon chemistry through a search for organic compounds, and to look for clues about planetary change.

Planetary Nebulae and their parent stellar populations. Tracing the mass assembly of M87 and Intracluster light in the Virgo cluster core

NASA Astrophysics Data System (ADS)

Arnaboldi, Magda; Longobardi, Alessia; Gerhard, Ortwin

2016-08-01

The diffuse extended outer regions of galaxies are hard to study because they are faint, with typical surface brightness of 1% of the dark night sky. We can tackle this problem by using resolved star tracers which remain visible at large distances from the galaxy centers. This article describes the use of Planetary Nebulae as tracers and the calibration of their properties as indicators of the star formation history, mean age and metallicity of the parent stars in the Milky Way and Local Group galaxies. We then report on the results from a deep, extended, planetary nebulae survey in a 0.5 deg2 region centered on the brightest cluster galaxy NGC 4486 (M87) in the Virgo cluster core, carried out with SuprimeCam@Subaru and FLAMES-GIRAFFE@VLT. Two planetary nebulae populations are identified out to 150 kpc distance from the center of M87. One population is associated with the M87 halo and the second one with the intracluster light in the Virgo cluster core. They have different line-of-sight velocity and spatial distributions, as well as different planetary nebulae specific frequencies and luminosity functions. The intracluster planetary nebulae in the surveyed region correspond to a luminosity of four times the luminosity of the Large Magellanic Cloud. The M87 halo planetary nebulae trace an older, more metal-rich, parent stellar population. A substructure detected in the projected phase-space of the line-of-sight velocity vs. major axis distance for the M87 halo planetary nebulae provides evidence for the recent accretion event of a satellite galaxy with luminosity twice that of M33. The satellite stars were tidally stripped about 1 Gyr ago, and reached apocenter at a major axis distance of 60-90 kpc from the center of M87. The M87 halo is still growing significantly at the distances where the substructure is detected.

Organic matter in carbonaceous chondrites, planetary satellites, asteroids and comets

NASA Technical Reports Server (NTRS)

Cronin, John R.; Pizzarello, Sandra; Cruikshank, Dale P.

1988-01-01

A detailed review is given of the organic compounds found in carbonaceous chondrite meteorites, especially the Murchison meteorite, and detected spectroscopically in other solar-system objects. The chemical processes by which the organic compounds could have formed in the early solar system and the conditions required for these processes are discussed, taking into account the possible alteration of the compounds during the lifetime of the meteoroid. Also considered are the implications for prebiotic evolution and the origin of life. Diagrams, graphs, and tables of numerical data are provided.

The development of spheroidal bodies theory for proto-planetary dynamics problem solving

NASA Astrophysics Data System (ADS)

Krot, A. M.

2007-08-01

There is not a full statistical equilibrium in a gas-dust proto-planetary cloud because of long relaxation time for proto-planet formation in own gravitational field. This protoplanetary system behavior can be described by Jeans equation in partial derivations relatively a distribution function. The problem for finding a general solution of Jeans equation is connected directly with an analytical expression for potential of gravitational field. Thus, the determination of gravitational potential is the main problem of statistical dynamics for proto-planetary system. The work shows this task of protoplanetary dynamics can be solved on the basis of spheroidal bodies theory [1]-[4]. Within the framework of this theory, cosmological bodies have fuzzy outlines and are represented by means of spheroidal forms. The proposed theory follows from the conception for forming a spheroidal body as a proto-planet from dust-like nebula; it permits to derive the form of distribution functions for an immovable spheroidal body [1],[2] and rotating one [3],[4] as well as their density masses (gravitational potentials and strengths) and also to find the distribution function of specific angular momentum for the rotating spheroidal body [4]. References: [1] A.M.Krot, Achievement in Modern Radioelectronics, 1996, no.8, pp.66-81 (in Russian). [2] A.M.Krot, Proc. SPIE's 13thAnnual Intern.Symp. "AeroSense", Orlando, Florida, USA, 1999, vol.3710, pp.1248-1259. [3] A.M.Krot, Proc. 35th COSPAR Scientific Assembly, Paris, France, 2004, Abstract A-00162. [4] A.Krot, Proc. EGU General Assembly, Vienna, Austria, 2006, Geophys. Res. Abstracts, vol.8, A-00216; SRef-ID: 1607-7962/gra/.

Determination of the microbial diversity of spacecraft assembly, testing and launch facilities: First results of the ESA project MiDiv

NASA Astrophysics Data System (ADS)

Rettberg, P.; Fritze, D.; Verbarg, S.; Nellen, J.; Horneck, G.; Stackebrandt, E.; Kminek, G.

2006-01-01

In the near future, an increasing number of in situ life detection and sample return missions to planets and other solar system bodies will be launched. The demand to control spacecraft-carried microbial contamination becomes obvious. COSPAR (Committee of Space Research) has defined guidelines and bioburden limits for different types of missions and target bodies. The first step in the implementation of these planetary protection guidelines encompasses a qualitative and quantitative inventory of the bioburden of spacecraft assembly facilities. With information about the composition of these microbial communities the development and/or optimization of adequate cleaning, disinfection, and sterilization procedures for spacecraft preparation before launch will be possible. In the ESA project MiDiv, we started to investigate the diversity of cultivable microorganisms found on spacecraft and spacecraft assembly halls using the satellites SMART-1 and ROSETTA as test objects. The analyses to date include cultivation of microorganisms by varying pH, temperature, oxygen, and pasteurization. A culture collection of bacterial isolates and a database of 16S RNA gene sequences have been established. The results of our preliminary work, including the numbers of colony forming units, differentiated as aerobes and facultative anaerobes as well as their phylogenetic classification, give a first overview of the breadth of physiological potential of the identified microorganisms and their capability to withstand various cleaning and sterilizing procedures currently used for the planetary protection.

Mars Observer data production, transfer, and archival: The data production assembly line

NASA Technical Reports Server (NTRS)

Childs, David B.

1993-01-01

This paper describes the data production, transfer, and archival process designed for the Mars Observer Flight Project. It addresses the developmental and operational aspects of the archive collection production process. The developmental aspects cover the design and packaging of data products for archival and distribution to the planetary community. Also discussed is the design and development of a data transfer and volume production process capable of handling the large throughput and complexity of the Mars Observer data products. The operational aspects cover the main functions of the process: creating data and engineering products, collecting the data products and ancillary products in a central repository, producing archive volumes, validating volumes, archiving, and distributing the data to the planetary community.

High surface area graphene-supported metal chalcogenide assembly

DOEpatents

Worsley, Marcus A.; Kuntz, Joshua; Orme, Christine A.

2016-04-19

A composition comprising at least one graphene-supported assembly, which comprises a three-dimensional network of graphene sheets crosslinked by covalent carbon bonds, and at least one metal chalcogenide compound disposed on said graphene sheets, wherein the chalcogen of said metal chalcogenide compound is selected from S, Se and Te. Also disclosed are methods for making and using the graphene-supported assembly, including graphene-supported MoS.sub.2. Monoliths with high surface area and conductivity can be achieved. Lower operating temperatures in some applications can be achieved. Pore size and volume can be tuned.

Exploring the Universe with the Hubble Space Telescope

NASA Technical Reports Server (NTRS)

1990-01-01

A general overview is given of the operations, engineering challenges, and components of the Hubble Space Telescope. Deployment, checkout and servicing in space are discussed. The optical telescope assembly, focal plane scientific instruments, wide field/planetary camera, faint object spectrograph, faint object camera, Goddard high resolution spectrograph, high speed photometer, fine guidance sensors, second generation technology, and support systems and services are reviewed.

Calculating Trajectories And Orbits

NASA Technical Reports Server (NTRS)

Alderson, Daniel J.; Brady, Franklyn H.; Breckheimer, Peter J.; Campbell, James K.; Christensen, Carl S.; Collier, James B.; Ekelund, John E.; Ellis, Jordan; Goltz, Gene L.; Hintz, Gerarld R.;

The micro-environmental impact of volatile organic compound emissions from large-scale assemblies of people in a confined space

USDA-ARS?s Scientific Manuscript database

Large-scale assemblies of people in a con'ned space can exert signi'cant impacts on the local air chemistry due to human emissions of volatile organics. Variations of air-quality in such small scale can be studied by quantifying 'ngerprint volatile organic compounds (VOCs) such as acetone, toluene, ...

Hybrid integration of III-V semiconductor lasers on silicon waveguides using optofluidic microbubble manipulation

PubMed Central

Jung, Youngho; Shim, Jaeho; Kwon, Kyungmook; You, Jong-Bum; Choi, Kyunghan; Yu, Kyoungsik

2016-01-01

Optofluidic manipulation mechanisms have been successfully applied to micro/nano-scale assembly and handling applications in biophysics, electronics, and photonics. Here, we extend the laser-based optofluidic microbubble manipulation technique to achieve hybrid integration of compound semiconductor microdisk lasers on the silicon photonic circuit platform. The microscale compound semiconductor block trapped on the microbubble surface can be precisely assembled on a desired position using photothermocapillary convective flows induced by focused laser beam illumination. Strong light absorption within the micro-scale compound semiconductor object allows real-time and on-demand microbubble generation. After the assembly process, we verify that electromagnetic radiation from the optically-pumped InGaAsP microdisk laser can be efficiently coupled to the single-mode silicon waveguide through vertical evanescent coupling. Our simple and accurate microbubble-based manipulation technique may provide a new pathway for realizing high precision fluidic assembly schemes for heterogeneously integrated photonic/electronic platforms as well as microelectromechanical systems. PMID:27431769

Azaphilones inhibit tau aggregation and dissolve tau aggregates in vitro.

PubMed

Paranjape, Smita R; Riley, Andrew P; Somoza, Amber D; Oakley, C Elizabeth; Wang, Clay C C; Prisinzano, Thomas E; Oakley, Berl R; Gamblin, T Chris

2015-05-20

The aggregation of the microtubule-associated protein tau is a seminal event in many neurodegenerative diseases, including Alzheimer's disease. The inhibition or reversal of tau aggregation is therefore a potential therapeutic strategy for these diseases. Fungal natural products have proven to be a rich source of useful compounds having wide varieties of biological activities. We have previously screened Aspergillus nidulans secondary metabolites for their ability to inhibit tau aggregation in vitro using an arachidonic acid polymerization protocol. One aggregation inhibitor identified was asperbenzaldehyde, an intermediate in azaphilone biosynthesis. We therefore tested 11 azaphilone derivatives to determine their tau assembly inhibition properties in vitro. All compounds tested inhibited tau filament assembly to some extent, and four of the 11 compounds had the advantageous property of disassembling preformed tau aggregates in a dose-dependent fashion. The addition of these compounds to the tau aggregates reduced both the total length and number of tau polymers. The most potent compounds were tested in in vitro reactions to determine whether they interfere with tau's normal function of stabilizing microtubules (MTs). We found that they did not completely inhibit MT assembly in the presence of tau. These derivatives are very promising lead compounds for tau aggregation inhibitors and, more excitingly, for compounds that can disassemble pre-existing tau filaments. They also represent a new class of anti-tau aggregation compounds with a novel structural scaffold.

Regolith-Derived Heat Shield for Planetary Body Entry and Descent System with In Situ Fabrication

NASA Technical Reports Server (NTRS)

Hogue, Michael D.; Mueller, Robert P.; Rasky, Daniel; Hintze, Paul; Sibille, Laurent

2012-01-01

In this paper we will discuss a new mass-efficient and innovative way of protecting high-mass spacecraft during planetary Entry, Descent & Landing (EDL). Heat shields fabricated in situ can provide a thermal-protection system (TPS) for spacecraft that routinely enter a planetary atmosphere. By fabricating the heat shield with space resources from regolith materials available on moons and asteroids, it is possible to avoid launching the heat-shield mass from Earth. Two regolith processing and manufacturing methods will be discussed: 1) Compression and sintering of the regolith to yield low density materials; 2) Formulations of a High-temperature silicone RTV (Room Temperature Vulcanizing) compound are used to bind regolith particles together. The overall positive results of torch flame impingement tests and plasma arc jet testing on the resulting samples will also be discussed.

X-ray remote sensing and in-situ spectroscopy for planetary exploration missions and gamma-ray remote sensing and in-situ spectroscopy for planetary exploration missions

NASA Technical Reports Server (NTRS)

Mahdavi, M.; Giboni, K. L.; Vajda, S.; Schweitzer, J.

1994-01-01

Detectors that will be used for planetary missions must have their responses calibrated in a reproducible manner. A calibration facility is being constructed at Schlumberger-Doll Research for gamma and x ray detectors. With this facility the detector response can be determined in an invariant and reproducible fashion. Initial use of the facility is expected for the MARS94 detectors. Work is continuing to better understand the rare earth oxyorthosilicates and to define their characteristics. This will allow a better use of these scintillators for planetary missions. In a survey of scintillating materials two scintillators were identified as promising candidates besides GSO, LSO, and YSO. These are CdWO4 and CsI(Tl). It will be investigated if a detector with a better overall performance can be assembled with various photon converters. Considerable progress was achieved in photomultiplier design. The length of an 1 inch diameter PMT could be reduced from 4.2 to 2.5 inches without performance degradation. This technology is being employed in the gamma ray detector for the NEAR project. A further weight and size reduction of the detector package can be achieved with miniaturized integrated power supplies.

A gravitational potential finding for rotating cosmological body in the context of proto-planetary dynamics problem solving

NASA Astrophysics Data System (ADS)

Krot, Alexander M.

2008-09-01

The statistical theory for a cosmological body forming (so-called the spheroidal body model) has been proposed in [1]-[9]. Within the framework of this theory, bodies have fuzzy outlines and are represented by means of spheroidal forms [1],[2]. In the work [3], it has been investigated a slowly evolving in time process of a gravitational compression of a spheroidal body close to an unstable equilibrium state. In the papers [4],[5], the equation of motion of particles inside the weakly gravitating spheroidal body modeled by means of an ideal liquid has been obtained. Using Schwarzschild's and Kerr's metrics a consistency of the proposed statistical model with the general relativity has been shown in [6]. The proposed theory follows from the conception for forming a spheroidal body from protoplanetary nebula [7],[8]; it permits to derive the form of distribution functions for an immovable [1]-[5] and rotating spheroidal body [6]-[8] as well as their density masses and also the distribution function of specific angular momentum of the rotating uniformly spheroidal body [7],[8]. It is well-known there is not a statistical equilibrium in a gas-dust proto-planetary cloud because of long relaxation time for proto-planets formation in own gravitational field. This proto-planetary system behavior can be described by Jeans' equation in partial derivations relative to a distribution function [9]. The problem for finding a general solution of Jeans' equation is connected directly with an analytical expression for potential of gravitational field. Thus, the determination of gravitational potential is the main problem of statistical dynamics for proto-planetary system [9]. This work shows this task of proto-planetary dynamics can be solved on the basis of spheroidal bodies theory. The proposed theory permits to derive the form of gravitational potential for a rotating spheroidal body at a long distance from its center. Using the obtained analytical expression for potential of gravitational field, the gravitational strength (as well as angular momentum space function) in a remote zone of a slowly gravitational compressed rotating spheroidal body is obtained. As a result, a distribution function describing mechanical state of proto-planetary system can be found from the Jeans' equation. References: [1] Krot AM. The statistical model of gravitational interaction of particles. Uspekhi Sovremennoï Radioelektroniki (special issue "Cosmic Radiophysics", Moscow) 1996; 8: 66-81 (in Russian). [2] Krot AM. Use of the statistical model of gravity for analysis of nonhomogeneity in earth surface. Proc. SPIE's 13th Annual Intern. Symposium "AeroSense", Orlando, Florida, USA, April 5-9, 1999; 3710: 1248-1259. [3] Krot AM. Statistical description of gravitational field: a new approach. Proc. SPIE's 14th Annual Intern.Symposium "AeroSense", Orlando, Florida, USA, April 24-28, 2000; 4038: 1318-1329. [4] Krot AM. Gravidynamical equations for a weakly gravitating spheroidal body. Proc. SPIE's 15th Annual Intern. Symposium "AeroSense", Orlando, Florida, USA, April 16-20, 2001; 4394: 1271-1282. [5] Krot AM. Development of gravidynamical equations for a weakly gravitating body in the vicinity of absolute zero temperature. Proc. 53rd Intern. Astronautical Congress (IAC) - The 2nd World Space Congress-2002, Houston, Texas, USA, October 10-19, 2002; Preprint IAC-02-J.P.01: 1-11. [6] Krot AM. The statistical model of rotating and gravitating spheroidal body with the point of view of general relativity. Proc. 35th COSPAR Scientific Assembly, Paris, France, July 18-25, 2004; Abstract-Nr. COSPAR 04-A- 00162. [7] Krot A. The statistical approach to exploring formation of Solar system. Proc. European Geoscinces Union (EGU) General Assembly, Vienna, Austria, April 02-07, 2006; Geophysical Research Abstracts, vol. 8: EGU06-A- 00216, SRef-ID: 1607-7962/gra/. [8] Krot AM. The statistical model of original and evolution planets of Solar system and planetary satellities. Proc. European Planetary Science Congress, Berlin, Germany, September 18-22, 2006; Planetary Research Abstracts, ESPC2006-A-00014. [9] Krot A. On the principal difficulties and ways to their solution in the theory of gravitational condensation of infinitely distributed dust substance. Proc. XXIV IUGG General Assembly, Perugia, Italy, July 2-13, 2007; GS002 Symposium "Gravity Field", Abstract GS002-3598: 143-144.

Urey Prize Lecture - Planetary evolution and the origin of life

NASA Technical Reports Server (NTRS)

Mckay, Christopher P.

1991-01-01

One of the principal questions concerning planetary evolution and life's origins relates to the early-earth organic material's origination in situ, outer solar system importation, or simple irrelevance to the emergence of organisms. Additional considerations encompass the character of interstellar organic material and its relationship to outer solar system organic compounds, and the possibility of life's emergence in the early Mars. Attention is given to the essentiality of liquid water for life-forms, in the role not only of a reaction medium among molecules but that of a basis for hydrophylic and hydrophobic groups' bonding.

Overview of the 2008 COSPAR Planetary Protection Policy Workshop

NASA Astrophysics Data System (ADS)

Rummel, John

In January 2008 the COSPAR Panel on Planetary Protection held a Policy Workshop in Montŕal, Canada to consider a number of recommendations that had been suggested at prior e Panel business meetings for updating and clarifying the COSPAR Planetary Protection Policy that had been adopted at the World Space Congress in 2002. One particular element of the Policy that was due for clarification was the definition of "Special Regions" on Mars, which was discussed by the Panel at a Special Regions Colloquium in Rome in September 2008, and which was recommended for updating by both the US National Research Council's Committee on Preventing the Forward Contamination of Mars and by a Special Regions Science Analysis Group organized by NASA under its Mars Exploration Program Analysis Group in 2006. In other business, the Workshop also discussed and adopted wording to reflect the planetary protection considerations associated with future human missions to Mars (subsequent to several NASA and ESA workshops defining those), and addressed the planetary protection categorizations of both Venus and the Earth's Moon. The Workshop also defined a plan to move forward on the categorization of Outer Planet Satellites (to be done in conjunction with SC's B and F), and revised certain portions of the wording of the 1983 version of the COSPAR policy statement, emphasized full participation by all national members in planetary protection decisions and the need to study the ethical considerations of space exploration, and provided for a traceable version of the policy to be assembled and maintained by the Panel. This talk will review the Montŕal Workshop, and use its themes to introduce the remaining speakers in the session. e

Planetary Protection Plan for an Antibody based instrument proposed for Mars2020

NASA Astrophysics Data System (ADS)

Smith, Heather; Parro, Víctor

The Signs Of Life Detector (SOLID) instrument is a high TRL level instrument proposed for the Mars 2020 instrument suite. In this presentation we describe the planetary protection instrument plan as if the instrument is classified as a life detection instrument compliant with Category IV(b) planetary protection mission requirements, NASA, ESA, and COSPAR policy. SOLID uses antibodies as a method for detecting organic and biomolecular components in soils. Due to the sensitive detection method, the scientific integrity of the instrument exceeds the planetary protection requirements. The instrument will be assembled and integrated in an ISO level 8 cleanroom or better (ISO 4 for the sample read out and fluidics components). Microbial reduction methods and assays employed are as follows: Wipe the outside and inside of the instrument with a mixture of isopropyl alcohol (70%) and water. Cell cultures will be the standard assay to determine enumeration of “viable” spores and other rapid assays such as LAL and ATP bioluminescence as secondary assays to verify the interior of the instrument is microbe free. SOLID’s design factors for contamination control include the following features: SOLID has the capability to heat the catchment tray to pyrolyze any Earth hitchhikers. There will also be an “air gap” of cm maintained between the sample acquisition device and the funnel inlet. This will prevent forward contamination of the sample collection device and reverse contamination of the detection unit. To mitigate false positives, SOLID will include anti-bodies for potential contaminants from organisms most commonly found in clean rooms. If selected for the Mars 2020 Rover, SOLID would be the first life detection instrument based on biomolecules sent by NASA, as such the planetary protection plan will set a precedence for future life detection instruments carrying biomolecules to other planetary bodies.

The Origin of Planetary Nitrogen

NASA Technical Reports Server (NTRS)

Owen, T.; Niemann, H.; Mahaffy, P.; Atreya, S.

2006-01-01

The nitrogen found today in planetary atmospheres appears to come from two sources: N2 and condensed, nitrogen-containing compounds. On Jupiter and thus presumably on the other giant planets, the nitrogen is present mainly as ammonia but was apparently delivered primarily in the form of N2, whereas on the inner planets and Titan, the nitrogen is present as N2 but was delivered as condensed compounds, dominated by ammonia. This analysis is consistent with abundance data from the Interstellar Medium and models for the solar nebula. For Jupiter and the inner planets, it is substantiated by measurements of N-l5/N-14 and is supported by investigations of comets and meteorites, soon to be supplemented by solar wind data from the Genesis Mission. The Cassini-Huygens Mission may be able to constrain models for Saturn s ammonia abundance that could test the proportion of N2 captured by the planet. The Titan story is less direct, depending on studies of noble gases. These studies in turn suggest an evolutionary stage of the early Earth s atmosphere that included the ammonia and methane postulated by S. L. Miller (1953) in his classical experiments on the production of biogenic compounds.

Gas exchange in wetlands: Controls and remote sensing

NASA Technical Reports Server (NTRS)

Hines, Mark E.

1992-01-01

This project was directed toward the quantification of fluxes of gaseous biogenic sulfur compounds from freshwater wetlands. These compounds (primarily hydrogen sulfide (H2S), dimethyl sulfide (DMS), and carbonyl sulfide (OCS)) have been implicated in the regulation of planetary albedo by the formation of microscopic atmospheric aerosols when they oxidize, and the further role of these aerosols as cloud condensation nuclei (CCN). The role of continental sources and sinks for these compounds is poorly understood. The present study was undertaken to quantify the source and sink strength of high latitude wetlands, and to delineate factors that regulate this flux.

Tetratopic phenyl compounds, related metal-organic framework materials and post-assembly elaboration

DOEpatents

Farha, Omar K.; Hupp, Joseph T.

2012-09-11

Disclosed are tetratopic carboxylic acid phenyl for use in metal-organic framework compounds. These compounds are useful in catalysis, gas storage, sensing, biological imaging, drug delivery and gas adsorption separation.

Tetratopic phenyl compounds, related metal-organic framework materials and post-assembly elaboration

DOEpatents

Farha, Omar K; Hupp, Joseph T

2013-06-25

Disclosed are tetratopic carboxylic acid phenyl for use in metal-organic framework compounds. These compounds are useful in catalysis, gas storage, sensing, biological imaging, drug delivery and gas adsorption separation.

Kinetic profile of amyloid formation in the presence of an aromatic inhibitor by nuclear magnetic resonance.

PubMed

Liu, Gai; Gaines, Jennifer C; Robbins, Kevin J; Lazo, Noel D

2012-10-11

The self-assembly of amyloid proteins into β-sheet rich assemblies is associated with human amyloidoses including Alzheimer's disease, Parkinson's disease, and type 2 diabetes. An attractive therapeutic strategy therefore is to develop small molecules that would inhibit protein self-assembly. Natural polyphenols are potential inhibitors of β-sheet formation. How these compounds affect the kinetics of self-assembly studied by thioflavin T (ThT) fluorescence is not understood primarily because their presence interferes with ThT fluorescence. Here, we show that by plotting peak intensities from nuclear magnetic resonance (NMR) against incubation time, kinetic profiles in the presence of the polyphenol can be obtained from which kinetic parameters of self-assembly can be easily determined. In applying this technique to the self-assembly of the islet amyloid polypeptide in the presence of curcumin, a biphenolic compound found in turmeric, we show that the kinetic profile is atypical in that it shows a prenucleation period during which there is no observable decrease in NMR peak intensities.

Control of microbial contamination.

NASA Technical Reports Server (NTRS)

Mcdade, J. J.

1971-01-01

Two specific applications are discussed of microbial contamination control in planetary quarantine. Under the first concept, using the clean room to control environmental microorganisms, the objective is to reduce the microbial species and keep the numbers of microorganisms within an enclosure at a low level. The clean room concept is aimed at obtaining a product that has a controlled and reduced level of microbial contamination. Under the second concept, using the microbiological barrier to control microbial contamination of a specific product, the barrier techniques are designed to prevent the entry of any microorganisms into a sterile work area. Thus the assembly of space flight hardware within the confines of a microbiological barrier is aimed at obtaining a sterile product. In theory and practice, both approaches are shown to be applicable to the planetary quarantine program.

What can Space Resources do for Astronomy and Planetary Science?

NASA Astrophysics Data System (ADS)

Elvis, Martin

2016-11-01

The rapid cost growth of flagship space missions has created a crisis for astronomy and planetary science. We have hit the funding wall. For the past 3 decades scientists have not had to think much about how space technology would change within their planning horizon. However, this time around enormous improvements in space infrastructure capabilities and, especially, costs are likely on the 20-year gestation periods for large space telescopes. Commercial space will lower launch and spacecraft costs substantially, enable cost-effective on-orbit servicing, cheap lunar landers and interplanetary cubesats by the early 2020s. A doubling of flagship launch rates is not implausible. On a longer timescale it will enable large structures to be assembled and constructed in space. These developments will change how we plan and design missions.

H2-,He-and CO2-line broadening coefficients and pressure shifts for the HITRAN database

NASA Astrophysics Data System (ADS)

Wilzewski, Jonas; Gordon, Iouli E.; Rothman, Laurence S.

2014-06-01

To increase the potential of the HITRAN database in astronomy, experimental and theoretical line broadening coefficients and line shifts of molecules of planetary interest broadened by H2,He,and CO2 have been assembled from available peer-reviewed sources. Since H2 and He are major constituents in the atmospheres of gas giants, and CO2 predominates in atmospheres of some rocky planets with volcanic activity, these spectroscopic data are important for studying planetary atmospheres. The collected data were used to create semi-empirical models for complete data sets from the microwave to the UV part of the spectrum of the studied molecules. The presented work will help identify the need for further investigations of broadening and shifting of spectral lines.

STS-34 Galileo processing at KSC's SAEF-2 planetary spacecraft facility

NASA Image and Video Library

1989-07-21

At the Kennedy Space Center's (KSC's) Spacecraft and Assembly Encapsulation Facility 2 (SAEF-2), the planetary spacecraft checkout facility, clean-suited technicians work on the Galileo spacecraft prior to moving it to the Vehicle Processing Facility (VPF) for mating with the inertial upper stage (IUS). Galileo is scheduled for launch aboard Atlantis, Orbiter Vehicle (OV) 104, on Space Shuttle Mission STS-34 in October 1989. It will be sent to the planet Jupiter, a journey which will taken more than six years to complete. In December 1995 as the two and one half ton spacecraft orbits Jupiter with its ten scientific instruments, a probe will be released to parachute into the Jovian atmosphere. NASA's Jet Propulsion Laboratory (JPL) manages the Galileo project. View provided by KSC.

Modeling, Modal Properties, and Mesh Stiffness Variation Instabilities of Planetary Gears

NASA Technical Reports Server (NTRS)

Parker, Robert G.; Lin, Jian; Krantz, Timothy L. (Technical Monitor)

2001-01-01

Planetary gear noise and vibration are primary concerns in their applications in helicopters, automobiles, aircraft engines, heavy machinery and marine vehicles. Dynamic analysis is essential to the noise and vibration reduction. This work analytically investigates some critical issues and advances the understanding of planetary gear dynamics. A lumped-parameter model is built for the dynamic analysis of general planetary gears. The unique properties of the natural frequency spectra and vibration modes are rigorously characterized. These special structures apply for general planetary gears with cyclic symmetry and, in practically important case, systems with diametrically opposed planets. The special vibration properties are useful for subsequent research. Taking advantage of the derived modal properties, the natural frequency and vibration mode sensitivities to design parameters are investigated. The key parameters include mesh stiffnesses, support/bearing stiffnesses, component masses, moments of inertia, and operating speed. The eigen-sensitivities are expressed in simple, closed-form formulae associated with modal strain and kinetic energies. As disorders (e.g., mesh stiffness variation. manufacturing and assembling errors) disturb the cyclic symmetry of planetary gears, their effects on the free vibration properties are quantitatively examined. Well-defined veering rules are derived to identify dramatic changes of natural frequencies and vibration modes under parameter variations. The knowledge of free vibration properties, eigen-sensitivities, and veering rules provide important information to effectively tune the natural frequencies and optimize structural design to minimize noise and vibration. Parametric instabilities excited by mesh stiffness variations are analytically studied for multi-mesh gear systems. The discrepancies of previous studies on parametric instability of two-stage gear chains are clarified using perturbation and numerical methods. The operating conditions causing parametric instabilities are expressed in closed-form suitable for design guidance. Using the well-defined modal properties of planetary gears, the effects of mesh parameters on parametric instability are analytically identified. Simple formulae are obtained to suppress particular instabilities by adjusting contact ratios and mesh phasing.

Generic and scientific constraints involving geoethics and geoeducation in planetary geosciences

NASA Astrophysics Data System (ADS)

Martínez-Frías, Jesús

2013-04-01

Geoscience education is a key factor in the academic, scientific and professional progress of any modern society. Geoethics is an interdisciplinary field, which involves Earth and Planetary Sciences as well as applied ethics, regarding the study of the abiotic world. These coss-cutting interactions linking scientific, societal and cultural aspects, consider our planet, in its modern approach, as a system and as a model. This new perspective is extremely important in the context of geoducation in planetary geosciences. In addition, Earth, our home planet, is the only planet in our solar system known to harbor life. This also makes it crucial to develop any scientific strategy and methodological technique (e.g. Raman spectroscopy) of searching for extraterrestrial life. In this context, it has been recently proposed [1-3] that the incorporation of the geoethical and geodiversity issues in planetary geology and astrobiology studies would enrich their methodological and conceptual character (mainly but not only in relation to planetary protection). Modern geoscience education must take into account that, in order to understand the origin and evolution of our planet, we need to be aware that the Earth is open to space, and that the study of meteorites, asteroids, the Moon and Mars is also essential for this purpose (Earth analogs are also unique sites to define planetary guidelines). Generic and scientific constraints involving geoethics and geoeducation should be incorporated into the teaching of all fundamental knowledge and skills for students and teachers. References: [1] Martinez-Frias, J. et al. (2009) 9th European Workshop on Astrobiology, EANA 09, 12-14 October 2009, Brussels, Belgiam. [2] Martinez-Frias, J., et al. (2010) 38th COSPAR Scientific Assembly. Protecting the Lunar and Martian Environments for Scientific Research, Bremen, Germany, 18-25 July. [3] Walsh et al. (2012) 43rd Lunar and Planetary Science Conference, 1910.pdf

Science with the James Webb Space Telescope

NASA Technical Reports Server (NTRS)

Gardner, Jonathan P.

2010-01-01

The scientific capabilities of the James Webb Space Telescope (JWST) fall into four themes. The End of the Dark Ages: First Light and Reionization theme seeks to identify the first luminous sources to form and to determine the ionization history of the universe. The Assembly of Galaxies theme seeks to determine how galaxies and the dark matter, gas, stars, metals, morphological structures, and active nuclei within them evolved from the epoch of reionization to the present. The Birth of Stars and Protoplanetary Systems theme seeks to unravel the birth and early evolution of stars, from infall onto dust-enshrouded protostars, to the genesis of planetary systems. The Planetary Systems and the Origins of Life theme seeks to determine the physical and chemical properties of planetary systems around nearby stars and of our own, and investigate the potential for life in those systems. To enable these for science themes, JWST will be a large (6.6m) cold (50K) telescope launched to the second Earth-Sun Lagrange point in 2014. It is the successor to the Hubble Space Telescope, and is a partnership of NASA, ESA and CSA.

Results of a XIPS(copyrighted) 25-cm Thruster Discharge Cathode Wear Test

NASA Technical Reports Server (NTRS)

Polk, James E.; Goebel, Dan M.; Tighe, William

2009-01-01

The Xenon Ion Propulsion System (XIPS(c)) 25-cm thruster produced by L-3 Communications Electron Technologies, Inc. offers a number of potential benefits for planetary missions, including high efficiency and high Isp over a large power throttling range and availability from an active product line. The thruster is qualified for use on commercial communications satellites, which have requirements differing from those for typical planetary missions. In particular, deep space missions require longer service life over a broad range of throttling conditions. A XIPS (c) discharge cathode assembly was subjected to a long duration test to extend operating experience at the maximum power point and at throttled conditions unique to planetary mission applications. A total of 16079 hours were accumulated at conditions corresponding to the full power engine operating point at 4.2 kWe, an intermediate power point at 2.76 kWe and the minimum power point at 0.49 kWe. Minor performance losses and cathode keeper erosion were observed at the full power point, but there were no changes in performance and negligible erosion at the intermediate and minimum power points.

Ongoing Wear Test of a XIPS(c) 25-Centimeter Thruster Discharge Cathode

NASA Technical Reports Server (NTRS)

Polk, James E.; Goebel, Dan M.; Tighe, William

2008-01-01

The Xenon Ion Propulsion System (XIPS(c)) 25-cm thruster produced by L-3 Communications Electron Technologies, Inc. offers a number of potential benefits for planetary missions, including high efficiency and high Isp over a large power throttling range and availability from an active product line. The thruster is qualified for use on commercial communications satellites, which have requirements differing from those for typical planetary missions. In particular, deep space missions require longer service life over a broad range of throttling conditions. A XIPS(c) discharge cathode assembly is currently undergoing a long duration test to extend operating experience at the maximum power point and at throttled conditions unique to planetary mission applications. A total of 11080 hours have been accumulated at conditions corresponding to the full power engine operating point at 4.2 kWe and an intermediate power point at 2.76 kWe. Minor performance losses and cathode keeper erosion were observed at the full power point, but there were no changes in performance and negligible erosion at the intermediate power point.

Planetary Drilling and Resources at the Moon and Mars

NASA Technical Reports Server (NTRS)

George, Jeffrey A.

2012-01-01

Drilling on the Moon and Mars is an important capability for both scientific and resource exploration. The unique requirements of spaceflight and planetary environments drive drills to different design approaches than established terrestrial technologies. A partnership between NASA and Baker Hughes Inc. developed a novel approach for a dry rotary coring wireline drill capable of acquiring continuous core samples at multi-meter depths for low power and mass. The 8.5 kg Bottom Hole Assembly operated at 100 We and without need for traditional drilling mud or pipe. The technology was field tested in the Canadian Arctic in sandstone, ice and frozen gumbo. Planetary resources could play an important role in future space exploration. Lunar regolith contains oxygen and metals, and water ice has recently been confirmed in a shadowed crater at the Moon.s south pole. Mars possesses a CO2 atmosphere, frozen water ice at the poles, and indications of subsurface aquifers. Such resources could provide water, oxygen and propellants that could greatly simplify the cost and complexity of exploration and survival. NASA/JSC/EP/JAG

Design of hydrophobic polyoxometalate hybrid assemblies beyond surfactant encapsulation.

PubMed

Song, Yu-Fei; McMillan, Nicola; Long, De-Liang; Thiel, Johannes; Ding, Yulong; Chen, Haisheng; Gadegaard, Nikolaj; Cronin, Leroy

2008-01-01

Grafting of C-6, C-16 and C-18 alkyl chains onto the hydrophilic Mn-Anderson clusters (compounds 2-4) has been achieved. Exchange of the tetrabutyl ammonium (TBA) with dimethyldioctadecyl ammonium (DMDOA) results in the formation of new polyoxometalate (POM) assemblies (compounds 5-6), in which the POM cores are covalently functionalized by hydrophilic alkyl-chains and enclosed by surfactant of DMDOABr. As a result, we have been able to design and synthesize POM-containing hydrophobic materials beyond surfactant encapsulation. In solid state, scanning electron and transmission electron microscopy (SEM and TEM) studies of the TBA salts of compounds 3 and 4 show highly ordered, uniform, reproducible assemblies with unique segmented rodlike morphology. SEM and TEM studies of the DMDOA salts of compounds 5 and 6 show that they form spherical and sea urchin 3D objects in different solvent systems. In solution, the physical properties of compound 5 and 6 (combination of surfactant-encapsulated cluster (SEC) and surface-grafted cluster (SGC)) show a liquid-to-gel phase transition in pure chloroform below 0 degrees C, which are much lower than other reported SECs. By utilizing light scattering measurements, the nanoparticle size for compounds 5 and 6 were measured at 5 degrees C and 30 degrees C, respectively. Other physical properties including differential scanning calorimetry have been reported.

A new series of HAPs as anti-HBV agents targeting at capsid assembly.

PubMed

Yang, Xiu-yan; Xu, Xiao-qian; Guan, Hua; Wang, Li-li; Wu, Qin; Zhao, Guo-ming; Li, Song

2014-09-01

A series of novel Heteroaryldihydropyrimidines (HAPs) derivatives were designed and synthesized as potent inhibitors of HBV capsid assembly. These compounds were prepared from efforts to optimize an earlier series of HAPs, and compounds Mo1, Mo7, Mo8, Mo10, Mo12, and Mo13 demonstrated potent inhibition of HBV DNA replication at submicromolar range. Copyright © 2014. Published by Elsevier Ltd.

Direct hierarchical assembly of nanoparticles

DOEpatents

Xu, Ting; Zhao, Yue; Thorkelsson, Kari

2014-07-22

The present invention provides hierarchical assemblies of a block copolymer, a bifunctional linking compound and a nanoparticle. The block copolymers form one micro-domain and the nanoparticles another micro-domain.

Probing the Interiors of the Ice Giants: Shock Compression of Water to 700 GPa and 3.8 g/cm³

DOE PAGES

Knudson, M. D.; Desjarlais, M. P.; Lemke, R. W.; ...

2012-02-27

Recently, there has been a tremendous increase in the number of identified extrasolar planetary systems. Our understanding of their formation is tied to exoplanet internal structure models, which rely upon equations of state of light elements and compounds such as water. Here, we present shock compression data for water with unprecedented accuracy that show that water equations of state commonly used in planetary modeling significantly overestimate the compressibility at conditions relevant to planetary interiors. Furthermore, we show that its behavior at these conditions, including reflectivity and isentropic response, is well-described by a recent first-principles based equation of state. These findingsmore » advocate that this water model be used as the standard for modeling Neptune, Uranus, and “hot Neptune” exoplanets and should improve our understanding of these types of planets.« less

Science with the James Webb Space Telescope

NASA Technical Reports Server (NTRS)

Gardner, Jonathan P.

2012-01-01

The science objectives of the James Webb Space Telescope fall into four themes. The End of the Dark Ages: First Light and Reionization theme seeks to identify the first luminous sources to form and to determine the ionization history of the universe. The Assembly of Galaxies theme seeks to determine how galaxies and the dark matter, gas, stars, metals, morphological structures, and black holes within them evolved from the epoch of reionization to the present. The Birth of Stars and Protoplanetary Systems theme seeks to unravel the birth and early evolution of stars, from infall onto dust-enshrouded protostars, to the genesis of planetary systems. The Planetary Systems and the Origins of Life theme seeks to determine the physical and chemical properties of planetary systems around nearby stars and of our own, and to investigate the potential for life in those systems. These four science themes were used to establish the design requirements for the observatory and instrumentation. Since Webb's capabilities are unique, those science themes will remain relevant through launch and operations and goals contained within these themes will continue to guide the design and implementation choices for the mission. More recently, it has also become clear that Webb will make major contributions to other areas of research, including dark energy, dark matter, active galactic nuclei, stellar populations, exoplanet characterization and Solar System objects. In this paper, we review the original four science themes and discuss how the scientific output of Webb will extend to these new areas of research. The James Webb Space Telescope was designed to meet science objectives in four themes: The End of the Dark Ages: First Light and Reionization, The Assembly of Galaxies, The Birth of Stars and Protoplanetary Systems, and Planetary Systems and the Origins of Life. More recently, it has become clear that Webb will also make major contributions to studies of dark energy, dark matter, active galactic nuclei, stellar populations, exoplanet characterization and Solar System objects. We review the original four science themes and discuss how the scientific output of Webb will extend to these new areas of research.

Experimental facility for testing nuclear instruments for planetary landing missions

NASA Astrophysics Data System (ADS)

Golovin, Dmitry; Mitrofanov, Igor; Litvak, Maxim; Kozyrev, Alexander; Sanin, Anton; Vostrukhin, Andrey

2017-04-01

The experimental facility for testing and calibration of nuclear planetology instruments has been built in the frame of JINR and Space Research Institute (Moscow) cooperation. The Martian soil model from silicate glass with dimensions 3.82 x 3.21 m and total weight near 30 tons has been assembled in the facility. The glass material was chosen for imitation of dry Martian regolith. The heterogeneous model has been proposed and developed to achieve the most possible similarity with Martian soil in part of the average elemental composition by adding layers of necessary materials, such as iron, aluminum, and chlorine. The presence of subsurface water ice is simulated by adding layers of polyethylene at different depths inside glass model assembly. Neutron generator was used as a neutron source to induce characteristic gamma rays for testing active neutron and gamma spectrometers to define elements composition of the model. The instrumentation was able to detect gamma lines attributed to H, O, Na, Mg, Al, Si, Cl, K, Ca and Fe. The identified elements compose up to 95 wt % of total mass of the planetary soil model. This results will be used for designing scientific instruments to performing experiments of active neutron and gamma ray spectroscopy on the surface of the planets during Russian and international missions Luna-Glob, Luna-Resource and ExoMars-2020.

Quality Assurance Specifications for Planetary Protection Assays

NASA Astrophysics Data System (ADS)

Baker, Amy

As the European Space Agency planetary protection (PP) activities move forward to support the ExoMars and other planetary missions, it will become necessary to increase staffing of labo-ratories that provide analyses for these programs. Standardization of procedures, a comprehen-sive quality assurance program, and unilateral training of personnel will be necessary to ensure that the planetary protection goals and schedules are met. The PP Quality Assurance/Quality Control (QAQC) program is designed to regulate and monitor procedures performed by labora-tory personnel to ensure that all work meets data quality objectives through the assembly and launch process. Because personnel time is at a premium and sampling schedules are often de-pendent on engineering schedules, it is necessary to have flexible staffing to support all sampling requirements. The most productive approach to having a competent and flexible work force is to establish well defined laboratory procedures and training programs that clearly address the needs of the program and the work force. The quality assurance specification for planetary protection assays has to ensure that labora-tories and associated personnel can demonstrate the competence to perform assays according to the applicable standard AD4. Detailed subjects included in the presentation are as follows: • field and laboratory control criteria • data reporting • personnel training requirements and certification • laboratory audit criteria. Based upon RD2 for primary and secondary validation and RD3 for data quality objectives, the QAQC will provide traceable quality assurance safeguards by providing structured laboratory requirements for guidelines and oversight including training and technical updates, standardized documentation, standardized QA/QC checks, data review and data archiving.

Evolution of a strategy for preparing bioactive small molecules by sequential multicomponent assembly processes, cyclizations, and diversification.

PubMed

Sahn, James J; Granger, Brett A; Martin, Stephen F

2014-10-21

A strategy for generating diverse collections of small molecules has been developed that features a multicomponent assembly process (MCAP) to efficiently construct a variety of intermediates possessing an aryl aminomethyl subunit. These key compounds are then transformed via selective ring-forming reactions into heterocyclic scaffolds, each of which possesses suitable functional handles for further derivatizations and palladium-catalyzed cross coupling reactions. The modular nature of this approach enables the facile construction of libraries of polycyclic compounds bearing a broad range of substituents and substitution patterns for biological evaluation. Screening of several compound libraries thus produced has revealed a large subset of compounds that exhibit a broad spectrum of medicinally-relevant activities.

Method of preparing a positive electrode for an electrochemical cell

DOEpatents

Tomczuk, Zygmunt

1979-01-01

A method of preparing an electrochemical cell including a metal sulfide as the positive electrode reactant and lithium alloy as the negative electrochemical reactant with an alkali metal, molten salt electrolyte is disclosed which permits the assembly to be accomplished in air. The electrode reactants are introduced in the most part as a sulfide of lithium and the positive electrode metal in a single-phase compound. For instance, Li.sub.2 FeS.sub.2 is a single-phase compound that is produced by the reaction of Li.sub.2 S and FeS. This compound is an intermediate in the positive electrode cycle from FeS.sub.2 to Fe and Li.sub.2 S. Its use minimizes volumetric changes from the assembled to the charged and discharged conditions of the electrode and minimizes electrode material interaction with air and moisture during assembly.

Determination of the Microbial Diversity of Spacecraft Assembly Facilities: First Results of the Project MiDiv

NASA Astrophysics Data System (ADS)

Rettberg, P.; Horneck, G.; Fritze, D.; Stackebrandt, E.; Kminek, G.

The first step in the implementation of planetary protection guidelines encompasses a qualitative and quantitative inventory of the bioburden of spacecraft assembly facilities. In such an artificial environment mainly microorganisms are to be expected that are brought in by the humans themselves and that are able to withstand the controlled air circulation, the low relative humidity, the moderately high temperature and the low-nutrient conditions in the clean rooms of the assembly facilities. With informations about the composition of these microbial communities the development and/or optimization of adequate cleaning and sterilization procedures for spacecraft preparation before launch will be possible. The bioburden assessment in spacecraft assembly facilities requires a standardized procedure for sampling the air and surfaces in the facilities as well as of the spacecraft, a transfer of the biological samples under controlled conditions to the analyzing laboratory and a scientifically approved set of methods for analysis. In the ESA project MiDiv we started to investigate the bioburden of spacecrafts using the satellites SMART-1 and ROSETTA as test objects. The analysis of the samples included so far cultivation on different media at different pH and temperatures with and without oxygen with and without pasteurization, establishment of a culture collection of bacteria and partial 16S rRNA gene analysis. The results of these preliminary measurements, the total number of microorganisms, the numbers of colony forming units, differentiated according to the subgroups of aerobes, facultative anaerobes and anaerobes, and the phylogenetic classification, will be assessed with respect to the physiological potential of the identified microorganisms to withstand the different cleaning and sterilizing procedures used up to now for planetary protection measures. In the next step the ability of selected microorganisms to survive has to tested under environmental conditions as they occur for example on Mars.

InSight Planetary Protection Status

NASA Astrophysics Data System (ADS)

Benardini, James; La Duc, Myron; Willis, Jason

The NASA Discovery Program’s next mission, Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSIght), consists of a single spacecraft that will be launched aboard an Atlas V 401 rocket from Vandenberg Air Force Base (Space Launch Complex 3E) during the March 2016 timeframe. The overarching mission goal is to illuminate the fundamentals of formation and evolution of terrestrial planets by investigating the interior structure and processes of Mars. The flight system consists of a heritage cruise stage, aeroshell (heatshield and backshell), and Lander from the 2008 Phoenix mission. Included in the lander payload are various cameras, a seismometer, an auxiliary sensor suite to measure wind, temperature, and pressure, and a mole to penetrate the regolith (<5 meters) and assess the subsurface geothermal gradient of Mars. Being a Mars lander mission without life detection instruments, InSight has been designated a PP Category Iva mission. As such, planetary protection bioburden requirements apply which require microbial reduction procedures and biological burden reporting. The InSight project is current with required PP documentation, having completed an approved Planetary Protection Plan, Subsidiary PP Plans, and a PP Implementation Plan. The InSight mission’s early planetary protection campaign has commenced, coinciding with the fabrication and assembly of payload and flight system hardware and the baseline analysis of existing flight spares. A report on the status of InSight PP activities will be provided.

Novel Trisubstituted Benzimidazoles, Targeting Mtb FtsZ, As A New Class of Antitubercular Agents

PubMed Central

Kumar, Kunal; Awasthi, Divya; Lee, Seung-Yub; Zanardi, Ilaria; Ruzsicska, Bela; Knudson, Susan; Tonge, Peter J.; Slayden, Richard A.; Ojima, Iwao

2010-01-01

Libraries of novel trisubstituted benzimidazoles were created through rational drug design. A good number of these benzimidazoles exhibited promising MIC values in the range of 0.5-6 μg/mL (2-15 μM) for their antibacterial activity against Mtb H37Rv strain. Moreover, five of the lead compounds also exhibited excellent activity against clinical Mtb strains with different drug-resistance profiles. All lead compounds do not show appreciable cytotoxicity (IC50 >200 μM) against Vero cells, which inhibit Mtb FtsZ assembly in a dose dependent manner. The two lead compounds unexpectedly showed enhancement of the GTPase activity of Mtb FtsZ. The result strongly suggests that the increased GTPase activity destabilizes FtsZ assembly leading to efficient inhibition of FtsZ polymerization and filament formation. The TEM and SEM analyses of Mtb FtsZ and Mtb cells, respectively, treated with a lead compound strongly suggest that lead benzimidazoles have a novel mechanism of action on the inhibition of Mtb FtsZ assembly and Z-ring formation. PMID:21126020

Novel trisubstituted benzimidazoles, targeting Mtb FtsZ, as a new class of antitubercular agents.

PubMed

Kumar, Kunal; Awasthi, Divya; Lee, Seung-Yub; Zanardi, Ilaria; Ruzsicska, Bela; Knudson, Susan; Tonge, Peter J; Slayden, Richard A; Ojima, Iwao

2011-01-13

Libraries of novel trisubstituted benzimidazoles were created through rational drug design. A good number of these benzimidazoles exhibited promising MIC values in the range of 0.5-6 μg/mL (2-15 μM) for their antibacterial activity against Mtb H37Rv strain. Moreover, five of the lead compounds also exhibited excellent activity against clinical Mtb strains with different drug-resistance profiles. All lead compounds did not show appreciable cytotoxicity (IC(50) > 200 μM) against Vero cells, which inhibited Mtb FtsZ assembly in a dose dependent manner. The two lead compounds unexpectedly showed enhancement of the GTPase activity of Mtb FtsZ. The result strongly suggests that the increased GTPase activity destabilizes FtsZ assembly, leading to efficient inhibition of FtsZ polymerization and filament formation. The TEM and SEM analyses of Mtb FtsZ and Mtb cells, respectively, treated with a lead compound strongly suggest that lead benzimidazoles have a novel mechanism of action on the inhibition of Mtb FtsZ assembly and Z-ring formation.

Extreme Ionizing-Radiation-Resistant Bacterium

NASA Technical Reports Server (NTRS)

Vaishampayan, Parag A.; Venkateswaran, Kasthuri J.; Schwendner, Petra

2012-01-01

There is a growing concern that desiccation and extreme radiation-resistant, non-spore-forming microorganisms associated with spacecraft surfaces can withstand space environmental conditions and subsequent proliferation on another solar body. Such forward contamination would jeopardize future life detection or sample return technologies. The prime focus of NASA s planetary protection efforts is the development of strategies for inactivating resistance-bearing microorganisms. Eradification techniques can be designed to target resistance-conferring microbial populations by first identifying and understanding their physiologic and biochemical capabilities that confers its elevated tolerance (as is being studied in Deinococcus phoenicis, as a result of this description). Furthermore, hospitals, food, and government agencies frequently use biological indicators to ensure the efficacy of a wide range of radiation- based sterilization processes. Due to their resistance to a variety of perturbations, the non-spore forming D. phoenicis may be a more appropriate biological indicator than those currently in use. The high flux of cosmic rays during space travel and onto the unshielded surface of Mars poses a significant hazard to the survival of microbial life. Thus, radiation-resistant microorganisms are of particular concern that can survive extreme radiation, desiccation, and low temperatures experienced during space travel. Spore-forming bacteria, a common inhabitant of spacecraft assembly facilities, are known to tolerate these extreme conditions. Since the Viking era, spores have been utilized to assess the degree and level of microbiological contamination on spacecraft and their associated spacecraft assembly facilities. Members of the non-spore-forming bacterial community such as Deinococcus radiodurans can survive acute exposures to ionizing radiation (5 kGy), ultraviolet light (1 kJ/sq m), and desiccation (years). These resistive phenotypes of Deinococcus enhance the potential for transfer, and subsequent proliferation, on another solar body such as Mars and Europa. These organisms are more likely to escape planetary protection assays, which only take into account presence of spores. Hence, presences of extreme radiation-resistant Deinococcus in the cleanroom facility where spacecraft are assembled pose a serious risk for integrity of life-detection missions. The microorganism described herein was isolated from the surfaces of the cleanroom facility in which the Phoenix Lander was assembled. The isolated bacterial strain was subjected to a comprehensive polyphasic analysis to characterize its taxonomic position. This bacterium exhibits very low 16SrRNA similarity with any other environmental isolate reported to date. Both phenotypic and phylogenetic analyses clearly indicate that this isolate belongs to the genus Deinococcus and represents a novel species. The name Deinococcus phoenicis was proposed after the Phoenix spacecraft, which was undergoing assembly, testing, and launch operations in the spacecraft assembly facility at the time of isolation. D. phoenicis cells exhibited higher resistance to ionizing radiation (cobalt-60; 14 kGy) than the cells of the D. radiodurans (5 kGy). Thus, it is in the best interest of NASA to thoroughly characterize this organism, which will further assess in determining the potential for forward contamination. Upon the completion of genetic and physiological characteristics of D. phoenicis, it will be added to a planetary protection database to be able to further model and predict the probability of forward contamination.

Extreme Ionizing-Radiation-Resistant Bacterium

NASA Technical Reports Server (NTRS)

Vaishampayan, Parag A.; Venkateswaran, Kasthuri J.; Schwendner, Petra

2013-01-01

There is a growing concern that desiccation and extreme radiation-resistant, non-spore-forming microorganisms associated with spacecraft surfaces can withstand space environmental conditions and subsequent proliferation on another solar body. Such forward contamination would jeopardize future life detection or sample return technologies. The prime focus of NASA s planetary protection efforts is the development of strategies for inactivating resistance-bearing micro-organisms. Eradi cation techniques can be designed to target resistance-conferring microbial populations by first identifying and understanding their physiologic and biochemical capabilities that confers its elevated tolerance (as is being studied in Deinococcus phoenicis, as a result of this description). Furthermore, hospitals, food, and government agencies frequently use biological indicators to ensure the efficacy of a wide range of radiation-based sterilization processes. Due to their resistance to a variety of perturbations, the nonspore forming D. phoenicis may be a more appropriate biological indicator than those currently in use. The high flux of cosmic rays during space travel and onto the unshielded surface of Mars poses a significant hazard to the survival of microbial life. Thus, radiation-resistant microorganisms are of particular concern that can survive extreme radiation, desiccation, and low temperatures experienced during space travel. Spore-forming bacteria, a common inhabitant of spacecraft assembly facilities, are known to tolerate these extreme conditions. Since the Viking era, spores have been utilized to assess the degree and level of microbiological contamination on spacecraft and their associated spacecraft assembly facilities. Members of the non-sporeforming bacterial community such as Deinococcus radiodurans can survive acute exposures to ionizing radiation (5 kGy), ultraviolet light (1 kJ/m2), and desiccation (years). These resistive phenotypes of Deinococcus enhance the potential for transfer, and subsequent proliferation, on another solar body such as Mars and Europa. These organisms are more likely to escape planetary protection assays, which only take into account presence of spores. Hence, presences of extreme radiation-resistant Deinococcus in the cleanroom facility where spacecraft are assembled pose a serious risk for integrity of life-detection missions. The microorganism described herein was isolated from the surfaces of the cleanroom facility in which the Phoenix Lander was assembled. The isolated bacterial strain was subjected to a comprehensive polyphasic analysis to characterize its taxonomic position. This bacterium exhibits very low 16SrRNA similarity with any other environmental isolate reported to date. Both phenotypic and phylogenetic analyses clearly indicate that this isolate belongs to the genus Deinococcus and represents a novel species. The name Deinococcus phoenicis was proposed after the Phoenix spacecraft, which was undergoing assembly, testing, and launch operations in the spacecraft assembly facility at the time of isolation. D. phoenicis cells exhibited higher resistance to ionizing radiation (cobalt-60; 14 kGy) than the cells of the D. radiodurans (5 kGy). Thus, it is in the best interest of NASA to thoroughly characterize this organism, which will further assess in determining the potential for forward contamination. Upon the completion of genetic and physiological characteristics of D. phoenicis, it will be added to a planetary protection database to be able to further model and predict the probability of forward contamination.

Production of organic compounds in plasmas - A comparison among electric sparks, laser-induced plasmas, and UV light

NASA Technical Reports Server (NTRS)

Scattergood, Thomas W.; Mckay, Christopher P.; Borucki, William J.; Giver, Lawrence P.; Van Ghyseghem, Hilde

1989-01-01

In order to ascertain the features of organic compound-production in planetary atmospheres under the effects of plasmas and shocks, various mixtures of N2, CH4, and H2 modeling the atmosphere of Titan were subjected to discrete sparks, laser-induced plasmas, and UV radiation. The experimental results obtained suggest that UV photolysis from the plasma is an important organic compound synthesis process, as confirmed by the photolysis of gas samples that were exposed to the light but not to the shock waves emitted by the sparks. The thermodynamic equilibrium theory is therefore incomplete in the absence of photolysis.

Book review: Advances in 40Ar/39Ar dating: From archaeology to planetary sciences

USGS Publications Warehouse

Cosca, Michael A.

2015-01-01

The recently published book Advances in 40Ar/39Ar Dating: From Archaeology to Planetary Sciences is a collection of 24 chapters authored by international scientists on topics ranging from decay constants to 40Ar/39Ar dating of extraterrestrial objects. As stated by the editors in their introduction, these chapters were assembled with the goal of providing technique-specific examples highlighting recent advances in the field of 40Ar/39Ar dating. As this is the first book truly dedicated to 40Ar/39Ar dating since the second edition printing of the argon geochronologist’s handbook Geochronology and Thermochronology by the 40Ar/39Ar Method (McDougall and Harrison 1999), a new collection of chapters highlighting recent advances in 40Ar/39Ar geochronology offers much to the interested reader.

Laboratory Investigation of Space and Planetary Dust Grains

NASA Technical Reports Server (NTRS)

Spann, James

2005-01-01

Dust in space is ubiquitous and impacts diverse observed phenomena in various ways. Understanding the dominant mechanisms that control dust grain properties and its impact on surrounding environments is basic to improving our understanding observed processes at work in space. There is a substantial body of work on the theory and modeling of dust in space and dusty plasmas. To substantiate and validate theory and models, laboratory investigations and space borne observations have been conducted. Laboratory investigations are largely confined to an assembly of dust grains immersed in a plasma environment. Frequently the behaviors of these complex dusty plasmas in the laboratory have raised more questions than verified theories. Space borne observations have helped us characterize planetary environments. The complex behavior of dust grains in space indicates the need to understand the microphysics of individual grains immersed in a plasma or space environment.

Organic-Inorganic Hybrid Polymers as Adsorbents for Removal of Heavy Metal Ions from Solutions: A Review

PubMed Central

Samiey, Babak; Cheng, Chil-Hung; Wu, Jiangning

2014-01-01

Over the past decades, organic-inorganic hybrid polymers have been applied in different fields, including the adsorption of pollutants from wastewater and solid-state separations. In this review, firstly, these compounds are classified. These compounds are prepared by sol-gel method, self-assembly process (mesopores), assembling of nanobuilding blocks (e.g., layered or core-shell compounds) and as interpenetrating networks and hierarchically structures. Lastly, the adsorption characteristics of heavy metals of these materials, including different kinds of functional groups, selectivity of them for heavy metals, effect of pH and synthesis conditions on adsorption capacity, are studied. PMID:28788483

Self-Assembly and Nanostructures in Organogels Based on a Bolaform Cholesteryl Imide Compound with Conjugated Aromatic Spacer

PubMed Central

Jiao, Ti-Feng; Gao, Feng-Qing; Shen, Xi-Hai; Zhang, Qing-Rui; Zhang, Xian-Fu; Zhou, Jing-Xin; Gao, Fa-Ming

2013-01-01

The self-assembly of small functional molecules into supramolecular structures is a powerful approach toward the development of new nanoscale materials and devices. As a class of self-assembled materials, low weight molecular organic gelators, organized in special nanoarchitectures through specific non-covalent interactions, has become one of the hot topics in soft matter research due to their scientific values and many potential applications. Here, a bolaform cholesteryl imide compound with conjugated aromatic spacer was designed and synthesized. The gelation behaviors in 23 solvents were investigated as efficient low-molecular-mass organic gelator. The experimental results indicated that the morphologies and assembly modes of as-formed organogels can be regulated by changing the kinds of organic solvents. Scanning electron microscopy and atomic force microscopy observations revealed that the gelator molecule self-assemble into different aggregates, from wrinkle and belt to fiber with the change of solvents. Spectral studies indicated that there existed different H-bond formations between imide groups and assembly modes. Finally, some rational assembly modes in organogels were proposed and discussed. The present work may give some insight to the design and character of new organogelators and soft materials with special structures. PMID:28788428

Rational design of bioactive, modularly assembled aminoglycosides targeting the RNA that causes myotonic dystrophy type 1.

PubMed

Childs-Disney, Jessica L; Parkesh, Raman; Nakamori, Masayuki; Thornton, Charles A; Disney, Matthew D

2012-12-21

Myotonic dystrophy type 1 (DM1) is caused when an expanded r(CUG) repeat (r(CUG)(exp)) binds the RNA splicing regulator muscleblind-like 1 protein (MBNL1) as well as other proteins. Previously, we reported that modularly assembled small molecules displaying a 6'-N-5-hexynoate kanamycin A RNA-binding module (K) on a peptoid backbone potently inhibit the binding of MBNL1 to r(CUG)(exp). However, these parent compounds are not appreciably active in cell-based models of DM1. The lack of potency was traced to suboptimal cellular permeability and localization. To improve these properties, second-generation compounds that are conjugated to a d-Arg(9) molecular transporter were synthesized. These modified compounds enter cells in higher concentrations than the parent compounds and are efficacious in cell-based DM1 model systems at low micromolar concentrations. In particular, they improve three defects that are the hallmarks of DM1: a translational defect due to nuclear retention of transcripts containing r(CUG)(exp); pre-mRNA splicing defects due to inactivation of MBNL1; and the formation of nuclear foci. The best compound in cell-based studies was tested in a mouse model of DM1. Modest improvement of pre-mRNA splicing defects was observed. These studies suggest that a modular assembly approach can afford bioactive compounds that target RNA.

Rational Design of Bioactive, Modularly Assembled Aminoglycosides Targeting the RNA that Causes Myotonic Dystrophy Type 1

PubMed Central

Childs-Disney, Jessica L.; Parkesh, Raman; Nakamori, Masayuki; Thornton, Charles A.; Disney, Matthew D.

2012-01-01

Myotonic dystrophy type 1 (DM1) is caused when an expanded r(CUG) repeat (r(CUG)exp) binds the RNA splicing regulator muscleblind-like 1 protein (MBNL1) as well as other proteins. Previously, we reported that modularly assembled small molecules displaying a 6′-N-5-hexynoate kanamycin A RNA-binding module (K) on a peptoid backbone potently inhibit the binding of MBNL1 to r(CUG)exp. However, these parent compounds are not appreciably active in cell-based models of DM1. The lack of potency was traced to suboptimal cellular permeability and localization. To improve these properties, second-generation compounds that are conjugated to a D-Arg9 molecular transporter were synthesized. These modified compounds enter cells in higher concentrations than the parent compounds and are efficacious in cell-based DM1 model systems at low micromolar concentrations. In particular, they improve three defects that are the hallmarks of DM1: a translational defect due to nuclear retention of transcripts containing r(CUG)exp; pre-mRNA splicing defects due to inactivation of MBNL1; and the formation of nuclear foci. The best compound in cell-based studies was tested in a mouse model of DM1. Modest improvement of pre-mRNA splicing defects was observed. These studies suggest that a modular assembly approach can afford bioactive compounds that target RNA. PMID:23130637

Pyrene-nucleobase conjugates: synthesis, oligonucleotide binding and confocal bioimaging studies.

PubMed

Jabłoński, Artur; Fritz, Yannic; Wagenknecht, Hans-Achim; Czerwieniec, Rafał; Bernaś, Tytus; Trzybiński, Damian; Woźniak, Krzysztof; Kowalski, Konrad

2017-01-01

Fluorescent pyrene-linker-nucleobase (nucleobase = thymine, adenine) conjugates with carbonyl and hydroxy functionalities in the linker were synthesized and characterized. X-ray single-crystal structure analysis performed for the pyrene-C(O)CH 2 CH 2 -thymine ( 2 ) conjugate reveals dimers of molecules 2 stabilized by hydrogen bonds between the thymine moieties. The photochemical characterization showed structure-dependent fluorescence properties of the investigated compounds. The conjugates bearing a carbonyl function represent weak emitters as compared to compounds with a hydroxy function in the linker. The self-assembly properties of pyrene nucleobases were investigated in respect to their binding to single and double strand oligonucleotides in water and in buffer solution. In respect to the complementary oligothymidine T 10 template in water, compounds 3 and 5 both show a self-assembling behavior according to canonical base-base pairing. However, in buffer solution, derivative 5 was much more effective than 3 in binding to the T 10 template. Furthermore the adenine derivative 5 binds to the double-stranded (dA) 10 -T 10 template with a self-assembly ratio of 112%. Such a high value of a self-assembly ratio can be rationalized by a triple-helix-like binding, intercalation, or a mixture of both. Remarkably, compound 5 also shows dual staining pattern in living HeLa cells. Confocal microscopy confirmed that 5 predominantly stains mitochondria but it also accumulates in the nucleoli of the cells.

Second Symposium on Chemical Evolution and the Origin of Life

NASA Technical Reports Server (NTRS)

Devincenzi, D. L. (Editor); model. (Editor)

1986-01-01

Recent findings by NASA Exobiology investigators are reported. Scientific papers are presented in the following areas: cosmic evolution of biogenic compounds, prebiotic evolution (planetary and molecular), early evolution of life (biological and geochemical), evolution of advanced life, solar system exploration, and the Search for Extraterrestrial Intelligence (SETI).

Second Symposium on Chemical Evolution and the Origin of Life

DOE Office of Scientific and Technical Information (OSTI.GOV)

Devincenzi, D.L.; Dufour, P.A.

1986-05-01

Recent findings by NASA Exobiology investigators are reported. Scientific papers are presented in the following areas: cosmic evolution of biogenic compounds, prebiotic evolution (planetary and molecular), early evolution of life (biological and geochemical), evolution of advanced life, solar system exploration, and the Search for Extraterrestrial Intelligence (SETI).

Search for and investigation of extraterrestrial forms of life

NASA Technical Reports Server (NTRS)

Rubin, A. B.

1975-01-01

Correct combinations of remote, analytic, and functional methods and measuring devices for detecting extraterrestrial life are elaborated. Considered are techniques and instruments available both on earth and aboard spacecraft and artificial planetary satellites. Emphasis is placed on the abiogenetic synthesis of organic compounds formed in photosynthesis on Mars.

Discovery of a Series of Acridinones as Mechanism-Based Tubulin Assembly Inhibitors with Anticancer Activity

PubMed Central

Magalhaes, Luma G.; Marques, Fernando B.; da Fonseca, Marina B.; Rogério, Kamilla R.; Graebin, Cedric S.; Andricopulo, Adriano D.

2016-01-01

Microtubules play critical roles in vital cell processes, including cell growth, division, and migration. Microtubule-targeting small molecules are chemotherapeutic agents that are widely used in the treatment of cancer. Many of these compounds are structurally complex natural products (e.g., paclitaxel, vinblastine, and vincristine) with multiple stereogenic centers. Because of the scarcity of their natural sources and the difficulty of their partial or total synthesis, as well as problems related to their bioavailability, toxicity, and resistance, there is an urgent need for novel microtubule binding agents that are effective for treating cancer but do not have these disadvantages. In the present work, our lead discovery effort toward less structurally complex synthetic compounds led to the discovery of a series of acridinones inspired by the structure of podophyllotoxin, a natural product with important microtubule assembly inhibitory activity, as novel mechanism-based tubulin assembly inhibitors with potent anticancer properties and low toxicity. The compounds were evaluated in vitro by wound healing assays employing the metastatic and triple negative breast cancer cell line MDA-MB-231. Four compounds with IC50 values between 0.294 and 1.7 μM were identified. These compounds showed selective cytotoxicity against MDA-MB-231 and DU-145 cancer cell lines and promoted cell cycle arrest in G2/M phase and apoptosis. Consistent with molecular modeling results, the acridinones inhibited tubulin assembly in in vitro polymerization assays with IC50 values between 0.9 and 13 μM. Their binding to the colchicine-binding site of tubulin was confirmed through competitive assays. PMID:27508497

Fabrication of gas impervious edge seal for a bipolar gas distribution assembly for use in a fuel cell

DOEpatents

Kaufman, Arthur; Werth, John

1986-01-01

A bipolar gas reactant distribution assembly for use in a fuel cell is disclosed, the assembly having a solid edge seal to prevent leakage of gaseous reactants wherein a pair of porous plates are provided with peripheral slits generally parallel to, and spaced apart from two edges of the plate, the slit being filled with a solid, fusible, gas impervious edge sealing compound. The plates are assembled with opposite faces adjacent one another with a layer of a fusible sealant material therebetween the slits in the individual plates being approximately perpendicular to one another. The plates are bonded to each other by the simultaneous application of heat and pressure to cause a redistribution of the sealant into the pores of the adjacent plate surfaces and to cause the edge sealing compound to flow and impregnate the region of the plates adjacent the slits and comingle with the sealant layer material to form a continuous layer of sealant along the edges of the assembled plates.

A Common Probe Design for Multiple Planetary Destinations

NASA Technical Reports Server (NTRS)

Hwang, H. H.; Allen, G. A., Jr.; Alunni, A. I.; Amato, M. J.; Atkinson, D. H.; Bienstock, B. J.; Cruz, J. R.; Dillman, R. A.; Cianciolo, A. D.; Elliott, J. O.;

Self-assembled nanostructures of linear arylacetylenes and their aza-substituted analogues

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Jia-Ju; Department of Physics and Materials Science and Centre of Super Diamond and Advanced Films; Yang, Xiong-Bo

2016-06-15

A series of linear phenylene ethynylene molecules have been synthesized, and aza-substitution has been used as a strategy to fine-tune the properties of the molecules. All the compounds exhibited pure blue emission both in solution and solid state, and fluorescence quantum yields as high as 0.66, 0.63 and 0.82 were found in chloroform solutions. The well-defined nanostructures such as quasi-cubes, cubes and rods were fabricated by self-assembly method from these compounds. The photophysical properties and aggregation behavior of self-assembled structures were analyzed in detail. The morphology as well as photophysical properties of these nanostructures have been tuned with selective requirements.

Status of the Planet Formation Imager (PFI) concept

NASA Astrophysics Data System (ADS)

Ireland, Michael J.; Monnier, John D.; Kraus, Stefan; Isella, Andrea; Minardi, Stefano; Petrov, Romain; ten Brummelaar, Theo; Young, John; Vasisht, Gautam; Mozurkewich, David; Rinehart, Stephen; Michael, Ernest A.; van Belle, Gerard; Woillez, Julien

2016-08-01

The Planet Formation Imager (PFI) project aims to image the period of planet assembly directly, resolving structures as small as a giant planet's Hill sphere. These images will be required in order to determine the key mechanisms for planet formation at the time when processes of grain growth, protoplanet assembly, magnetic fields, disk/planet dynamical interactions and complex radiative transfer all interact - making some planetary systems habitable and others inhospitable. We will present the overall vision for the PFI concept, focusing on the key technologies and requirements that are needed to achieve the science goals. Based on these key requirements, we will define a cost envelope range for the design and highlight where the largest uncertainties lie at this conceptual stage.

Overview of the NASA automation and robotics research program

NASA Technical Reports Server (NTRS)

Holcomb, Lee; Larsen, Ron

1985-01-01

NASA studies over the last eight years have identified five opportunities for the application of automation and robotics technology: (1) satellite servicing; (2) system monitoring, control, sequencing and diagnosis; (3) space manufacturing; (4) space structure assembly; and (5) planetary rovers. The development of these opportunities entails two technology R&D thrusts: telerobotics and system autonomy; both encompass such concerns as operator interface, task planning and reasoning, control execution, sensing, and systems integration.

Self-Assembly and Drug Release Capacities of Organogels via Some Amide Compounds with Aromatic Substituent Headgroups

PubMed Central

Zhang, Lexin; Jiao, Tifeng; Ma, Kai; Xing, Ruirui; Liu, Yamei; Xiao, Yong; Zhou, Jingxin; Zhang, Qingrui; Peng, Qiuming

2016-01-01

In this work, some amide compounds with different aromatic substituent headgroups were synthesized and their gelation self-assembly behaviors in 22 solvents were characterized as new gelators. The obtained results indicated that the size of aromatic substituent headgroups in molecular skeletons in gelators showed crucial effect in the gel formation and self-assembly behavior of all compounds in the solvents used. Larger aromatic headgroups in molecular structures in the synthesized gelator molecules are helpful to form various gel nanostructures. Morphological investigations showed that the gelator molecules can self-assembly and stack into various organized aggregates with solvent change, such as wrinkle, belt, rod, and lamella-like structures. Spectral characterizations suggested that there existed various weak interactions including π-π stacking, hydrogen bonding, and hydrophobic forces due to aromatic substituent headgroups and alkyl substituent chains in molecular structures. In addition, the drug release capacities experiments demonstrated that the drug release rate in present obtained gels can be tuned by adjusting the concentrations of dye. The present work would open up enormous insight to design and investigate new kind of soft materials with designed molecular structures and tunable drug release performance. PMID:28773663

Optical and Near-infrared Spectra of σ Orionis Isolated Planetary-mass Objects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zapatero Osorio, M. R.; Béjar, V. J. S.; Ramírez, K. Peña, E-mail: mosorio@cab.inta-csic.es, E-mail: vbejar@iac.es, E-mail: karla.pena@uantof.cl

We have obtained low-resolution optical (0.7–0.98 μ m) and near-infrared (1.11–1.34 μ m and 0.8–2.5 μ m) spectra of 12 isolated planetary-mass candidates ( J = 18.2–19.9 mag) of the 3 Myr σ Orionis star cluster with the aim of determining the spectroscopic properties of very young, substellar dwarfs and assembling a complete cluster mass function. We have classified our targets by visual comparison with high- and low-gravity standards and by measuring newly defined spectroscopic indices. We derived L0–L4.5 and M9–L2.5 using high- and low-gravity standards, respectively. Our targets reveal clear signposts of youth, thus corroborating their cluster membership andmore » planetary masses (6–13 M {sub Jup}). These observations complete the σ Orionis mass function by spectroscopically confirming the planetary-mass domain to a confidence level of ∼75%. The comparison of our spectra with BT-Settl solar metallicity model atmospheres yields a temperature scale of 2350–1800 K and a low surface gravity of log g ≈ 4.0 [cm s{sup −2}], as would be expected for young planetary-mass objects. We discuss the properties of the cluster’s least-massive population as a function of spectral type. We have also obtained the first optical spectrum of S Ori 70, a T dwarf in the direction of σ Orionis. Our data provide reference optical and near-infrared spectra of very young L dwarfs and a mass function that may be used as templates for future studies of low-mass substellar objects and exoplanets. The extrapolation of the σ Orionis mass function to the solar neighborhood may indicate that isolated planetary-mass objects with temperatures of ∼200–300 K and masses in the interval 6–13 M {sub Jup} may be as numerous as very low-mass stars.« less

Microcomponent assembly for efficient contacting of fluid

DOEpatents

Drost, Monte K.; Wegeng, Robert S.; Friedrich, Michele; Hanna, William T.; Call, Charles J.; Kurath, Dean E.

2000-01-01

The present invention is a fundamental method and apparatus of a microcomponent assembly that overcomes the inherent limitations of state of the art chemical separations. The fundamental element enabling miniaturization is the porous contactor contained within a microcomponent assembly for mass transfer of a working compound from a first medium to a second medium. The porous contactor has a thickness, and a plurality of pores extending through the thickness. The pores are of a geometry cooperating with a boundary tension of one or the other or both of the media thereby preventing migration of one, other or both through the microporous contactor while permitting passage of the working compound. In the microcomponent assembly, the porous contactor is placed between a first laminate such that a first space or first microplenum is formed between the microporous contactor and the first laminate. Additionally, a cover sheet provides a second space or second plenum between the porous contactor and the cover sheet.

Miniaturized Environmental Scanning Electron Microscope for In Situ Planetary Studies

NASA Technical Reports Server (NTRS)

Gaskin, Jessica; Abbott, Terry; Medley, Stephanie; Gregory, Don; Thaisen, Kevin; Taylor , Lawrence; Ramsey, Brian; Jerman, Gregory; Sampson, Allen; Harvey, Ralph

2010-01-01

The exploration of remote planetary surfaces calls for the advancement of low power, highly-miniaturized instrumentation. Instruments of this nature that are capable of multiple types of analyses will prove to be particularly useful as we prepare for human return to the moon, and as we continue to explore increasingly remote locations in our Solar System. To this end, our group has been developing a miniaturized Environmental-Scanning Electron Microscope (mESEM) capable of remote investigations of mineralogical samples through in-situ topographical and chemical analysis on a fine scale. The functioning of an SEM is well known: an electron beam is focused to nanometer-scale onto a given sample where resulting emissions such as backscattered and secondary electrons, X-rays, and visible light are registered. Raster scanning the primary electron beam across the sample then gives a fine-scale image of the surface topography (texture), crystalline structure and orientation, with accompanying elemental composition. The flexibility in the types of measurements the mESEM is capable of, makes it ideally suited for a variety of applications. The mESEM is appropriate for use on multiple planetary surfaces, and for a variety of mission goals (from science to non-destructive analysis to ISRU). We will identify potential applications and range of potential uses related to planetary exploration. Over the past few of years we have initiated fabrication and testing of a proof-of-concept assembly, consisting of a cold-field-emission electron gun and custom high-voltage power supply, electrostatic electron-beam focusing column, and scanning-imaging electronics plus backscatter detector. Current project status will be discussed. This effort is funded through the NASA Research Opportunities in Space and Earth Sciences - Planetary Instrument Definition and Development Program.

Recent advances in chemical evolution and the origins of life

NASA Technical Reports Server (NTRS)

Oro, John; Lazcano, Antonio

1992-01-01

Consideration is given to the ideas of Oparin and Haldane who independently suggested more than 60 years ago that the first forms of life were anaerobic, heterotrophic bacteria that emerged as the result of a long period of chemical abiotic synthesis of organic compounds. It is suggested that at least some requirements for life are met in the Galaxy due to the cosmic abundance of carbon, nitrogen, oxygen, and other biogenic elements; the existence of extraterrestrial organic compounds; and the processes of stellar and interstellar planetary formation.

Backbone N xH compounds at high pressures

DOE PAGES

Goncharov, Alexander F.; Holtgrewe, Nicholas; Qian, Guangrui; ...

2015-06-05

Optical and synchrotron x-ray diffraction diamond anvil cell experiments have been combined with first principles theoretical structure predictions to investigate mixtures of N 2 and H 2 up to 55 GPa. Our experiments show the formation of structurally complex van der Waals compounds above 10 GPa. However, we found that these N xH (0.52, H 2, and NH 3 above approximately 40 GPa. Lastly, our results suggest new pathways for synthesis of environmentally benign high energy-density materials. These materials could also exist as alternative planetary ices.

New Strategies and Methods to Study Interactions between Tobacco Mosaic Virus Coat Protein and Its Inhibitors

PubMed Central

Li, Xiangyang; Chen, Zhuo; Jin, Linhong; Hu, Deyu; Yang, Song

2016-01-01

Studies of the targets of anti-viral compounds are hot topics in the field of pesticide research. Various efficient anti-TMV (Tobacco Mosaic Virus) compounds, such as Ningnanmycin (NNM), Antofine (ATF), Dufulin (DFL) and Bingqingxiao (BQX) are available. However, the mechanisms of the action of these compounds on targets remain unclear. To further study the mechanism of the action of the anti-TMV inhibitors, the TMV coat protein (TMV CP) was expressed and self-assembled into four-layer aggregate disks in vitro, which could be reassembled into infectious virus particles with TMV RNA. The interactions between the anti-TMV compounds and the TMV CP disk were analyzed by size exclusion chromatography, isothermal titration calorimetry and native-polyacrylamide gel electrophoresis methods. The results revealed that assembly of the four-layer aggregate disk was inhibited by NNM; it changed the four-layer aggregate disk into trimers, and affected the regular assembly of TMV CP and TMV RNA. The four-layer aggregate disk of TMV CP was little inhibited by ATF, DFL and BQX. Our results provide original data, as well as new strategies and methods, for research on the mechanism of action of anti-viral drugs. PMID:26927077

California; Antelope Valley Air Quality Management District; VOCs from Motor Vehicle Assembly Coating Operations

EPA Pesticide Factsheets

EPA is proposing to approve a revision to the Antelope Valley Air Quality Management District portion of the California SIP concerning emissions of volatile organic compounds (VOCs) from motor vehicle assembly coating operations.

Biosynthesis: Reprogramming assembly lines

NASA Astrophysics Data System (ADS)

Menon, Binuraj R. K.; Jenner, Matthew

2018-03-01

Rational engineering of biosynthetic assembly lines for production of new compounds is an attractive prospect, yet it presents many challenges. Learning from biology, some of the rules for expanding the chemical diversity of non-ribosomal peptides have been uncovered in two recent studies.

A Comparison of Observed Abundances in Five Well-Studied Planetary Nebulae

NASA Astrophysics Data System (ADS)

Tanner, Jolene; Balick, B.; Kwitter, K. B.

2013-01-01

We have assembled data and derived abundances in several recent careful studies for five bright planetary nebulae (PNe) of low, moderate, and high ionization and relatively simple morphology. Each of the studies employ different apertures, aperture placement, and facilities for the observations. Various methods were used to derive total abundances. All used spectral windows that included [OII]3727 in the UV through Argon lines in the red. Our ultimate goal is to determine the extent to which the derived abundances are consistent. We show that the reddening-corrected line ratios are surprisingly similar despite the different modes of observation and that the various abundance analysis methods yield generally consistent results for He/H, N/H, O/H, and Ne/H (within 50% with a few larger deviations). In addition we processed the line ratios from the different sources using a common abundance derivation method (ELSA) to search for clues of systematic methodological inconsistencies. None were uncovered.

The James Webb Space Telescope: Capabilities for Exoplanet Science

NASA Technical Reports Server (NTRS)

Clampin, Mark

2011-01-01

The James Webb Space Telescope (JWST) is a large aperture (6.5 meter), cryogenic space telescope with a suite of near and mid-infrared instruments covering the wavelength range of 0.6 micron to 28 micron. JWST's primary science goal is to detect and characterize the first galaxies. It will also study the assembly of galaxies, stellar and planetary system formation, and the formation and evolution of planetary systems. We will review the design of JWST, and discuss the current status of the project, with emphasis on recent progress in the construction of the observatory. We also review the capabilities of the observatory for observations of exosolar planets and debris disks by means of coronagraphic imaging, and high contrast imaging and spectroscopy. This discussion will focus on the optical and thermal performance of the observatory, and will include the current predictions for the performance of the observatory, with special reference to the demands of exoplanet science observations.

Oxygen Buffering in High Pressure Solid Media Assemblies: New Approach Enabling Study of fO2 from IW-4 to IW+4.5

NASA Technical Reports Server (NTRS)

Righter, K.; Pando, K. M.; Ross, D. K.; Butterworth, A. L.; Gainsforth, Z.; Jilly-Rehak, C. E.; Westphal, A. J.

2017-01-01

Oxygen fugacity is an intensive parameter that controls some fundamental chemical and physical properties in planetary materials. In terrestrial magmas high fO2 promotes magnetite stability and low fO2 causes Fe-enrichment due to magnetite suppression. In lunar and asteroidal basalts, low fO2 can allow metal to be stable. Experimental studies will therefore be most useful if they are done at a specific and relevant fO2 for the samples under consideration. Control of fO2 in the solid media apparatus (piston cylinder multi-anvil) has relied on either sliding sensors or graphite capsule buffering, which are of limited application to the wide range of fO2 recorded in planetary or astromaterials. Here we describe a new approach that allows fO2 to be specified across a wide range of values relevant to natural samples.

Drug delivery by water-soluble organometallic cages.

PubMed

Therrien, Bruno

2012-01-01

Until recently, organometallic derivatives were generally viewed as moisture- and air-sensitive compounds, and consequently very challenging to synthesise and very demanding in terms of laboratory requirements (Schlenk techniques, dried solvent, glove box). However, an increasing number of stable, water-soluble organometallic compounds are now available, and organometallic chemistry in aqueous phase is a flourishing area of research. As such, coordination-driven self-assemblies using organometallic building blocks are compatible with water, thus opening new perspectives in bio-organometallic chemistry.This chapter gives a short history of coordination-driven self-assembly, with a special attention to organometallic metalla-cycles, especially those composed of half-sandwich complexes. These metalla-assemblies have been used as sensors, as anticancer agents, as well as drug carriers.

Method for forming hermetic seals

NASA Technical Reports Server (NTRS)

Gallagher, Brian D.

1987-01-01

The firmly adherent film of bondable metal, such as silver, is applied to the surface of glass or other substrate by decomposing a layer of solution of a thermally decomposable metallo-organic deposition (MOD) compound such as silver neodecanoate in xylene. The MOD compound thermally decomposes into metal and gaseous by-products. Sealing is accomplished by depositing a layer of bonding metal, such as solder or a brazing alloy, on the metal film and then forming an assembly with another high melting point metal surface such as a layer of Kovar. When the assembly is heated above the temperature of the solder, the solder flows, wets the adjacent surfaces and forms a hermetic seal between the metal film and metal surface when the assembly cools.

Self-assembly micro optical filter

NASA Astrophysics Data System (ADS)

Zhang, Ping (Cerina); Le, Kevin; Malalur-Nagaraja-Rao, Smitha; Hsu, Lun-Chen; Chiao, J.-C.

2006-01-01

Optical communication and sensor industry face critical challenges in manufacturing for system integration. Due to the assembly complexity and integration platform variety, micro optical components require costly alignment and assembly procedures, in which many required manual efforts. Consequently, self-assembly device architectures have become a great interest and could provide major advantages over the conventional optical devices. In this paper, we discussed a self-assembly integration platform for micro optical components. To demonstrate the adaptability and flexibility of the proposed optical device architectures, we chose a commercially available MEMS fabrication foundry service - MUMPs (Multi-User MEMS Process). In this work, polysilicon layers of MUMPS are used as the 3-D structural material for construction of micro component framework and actuators. However, because the polysilicon has high absorption in the visible and near infrared wavelength ranges, it is not suitable for optical interaction. To demonstrate the required optical performance, hybrid integration of materials was proposed and implemented. Organic compound materials were applied on the silicon-based framework to form the required optical interfaces. Organic compounds provide good optical transparency, flexibility to form filters or lens and inexpensive manufacturing procedures. In this paper, we have demonstrated a micro optical filter integrated with self-assembly structures. We will discuss the self-assembly mechanism, optical filter designs, fabrication issues and results.

Pyrene–nucleobase conjugates: synthesis, oligonucleotide binding and confocal bioimaging studies

PubMed Central

Jabłoński, Artur; Fritz, Yannic; Wagenknecht, Hans-Achim; Czerwieniec, Rafał; Bernaś, Tytus; Trzybiński, Damian; Woźniak, Krzysztof

2017-01-01

Fluorescent pyrene–linker–nucleobase (nucleobase = thymine, adenine) conjugates with carbonyl and hydroxy functionalities in the linker were synthesized and characterized. X-ray single-crystal structure analysis performed for the pyrene–C(O)CH2CH2–thymine (2) conjugate reveals dimers of molecules 2 stabilized by hydrogen bonds between the thymine moieties. The photochemical characterization showed structure-dependent fluorescence properties of the investigated compounds. The conjugates bearing a carbonyl function represent weak emitters as compared to compounds with a hydroxy function in the linker. The self-assembly properties of pyrene nucleobases were investigated in respect to their binding to single and double strand oligonucleotides in water and in buffer solution. In respect to the complementary oligothymidine T10 template in water, compounds 3 and 5 both show a self-assembling behavior according to canonical base–base pairing. However, in buffer solution, derivative 5 was much more effective than 3 in binding to the T10 template. Furthermore the adenine derivative 5 binds to the double-stranded (dA)10–T10 template with a self-assembly ratio of 112%. Such a high value of a self-assembly ratio can be rationalized by a triple-helix-like binding, intercalation, or a mixture of both. Remarkably, compound 5 also shows dual staining pattern in living HeLa cells. Confocal microscopy confirmed that 5 predominantly stains mitochondria but it also accumulates in the nucleoli of the cells. PMID:29259662

Diffusion welded nonconsumable electrode assembly and use thereof for electrolytic production of metals and silicon

DOEpatents

Byrne, Stephen C.; Vasudevan, Asuri K.

1984-01-01

A nonconsumable electrode assembly suitable for use in the production of metal by electrolytic reduction of a metal compound dissolved in a molten salt, the assembly comprising a metal conductor diffusion welded to a portion of a ceramic electrode body having a level of free metal or metal alloy sufficient to effect a metal bond.

Hydromechanical transmission with hydrodynamic drive

DOEpatents

Orshansky, Jr., deceased, Elias; Weseloh, William E.

1979-01-01

This transmission has a first planetary gear assembly having first input means connected to an input shaft, first output means, and first reaction means, and a second planetary gear assembly having second input means connected to the first input means, second output means, and second reaction means connected directly to the first reaction means by a reaction shaft. First clutch means, when engaged, connect the first output means to an output shaft in a high driving range. A hydrodynamic drive is used; for example, a torque converter, which may or may not have a stationary case, has a pump connected to the second output means, a stator grounded by an overrunning clutch to the case, and a turbine connected to an output member, and may be used in a starting phase. Alternatively, a fluid coupling or other type of hydrodynamic drive may be used. Second clutch means, when engaged, for connecting the output member to the output shaft in a low driving range. A variable-displacement hydraulic unit is mechanically connected to the input shaft, and a fixed-displacement hydraulic unit is mechanically connected to the reaction shaft. The hydraulic units are hydraulically connected together so that when one operates as a pump the other acts as a motor, and vice versa. Both clutch means are connected to the output shaft through a forward-reverse shift arrangement. It is possible to lock out the torque converter after the starting phase is over.

Isolation of the Paenibacillus phoenicis, a Spore-Forming Bacterium

NASA Technical Reports Server (NTRS)

Benardini, James N.; Vaishampayan, Parag A.; Venkateswaran, Kasthuri J.; Osman, Shariff; Satomi, Masataka

2010-01-01

A microorganism was isolated from the surfaces of the cleanroom facility in which the Phoenix lander was assembled. The isolated bacterial strain was subjected to a comprehensive polyphasic analysis to characterize its taxonomic position. Both phenotypic and phylogenetic analyses clearly indicate that this isolate belongs to the genus Paenibacillus and represents a novel species. Bacillus spores have been utilized to assess the degree and level of microbiological contamination on spacecraft and their associated spacecraft assembly facilities. Spores of Bacillus species are of particular concern to planetary protection due to the extreme resistance of some members of the genus to space environmental conditions such as UV and gamma radiation, vacuum, oxidation, and temperature fluctuation. These resistive spore phenotypes have enhanced potential for transfer, and subsequent proliferation, of terrestrial microbes on another solar body. Due to decreased nutrient conditions within spacecraft assembly facility clean rooms, the vegetative cells of Bacillus species and other spore-forming Paenibacillus species are induced to sporulate, thereby enhancing their survivability of bioreduction

Hardy Bacterium Isolated From Two Geographically Distinct Spacecraft Assembly Cleanroom Facilities

NASA Technical Reports Server (NTRS)

Vaisham-payan, Parag A.; Venkateswaran, Kasthuri J.; Schwendner, Petra; Moissl-Eichinger, Christine

2012-01-01

Earlier studies have confirmed that a tenacious hardy bacterial population manages to persist and survive throughout a spacecraft assembly process. The widespread detection of these organisms underscores the challenges in eliminating them completely. Only comprehensive and repetitive microbial diversity studies of geographically distinct cleanroom facilities will bolster the understanding of planetary protection relevant microbes. Extensive characterizations of the physiological traits demonstrated by cleanroom microbes will aid NASA in gauging the forward contamination risk that hardy bacteria (such as Tersicoccus phoenicis) pose to spacecraft. This study reports on the isolation and identification of two gram-positive, non-motile, non-spore-forming bacterial strains from the spacecraft assembly facilities at Kennedy Space Center, Florida, USA and Centre Spatial Guyanais, Kourou, French Guiana. DNA-DNA relatedness values between the novel strains indicates that these novel strains were indeed members of a same species. Phylogenetic evidence derived from a 16S ribosomal DNA analysis indicated that both the novel strains are less closely related to all other Arthrobacter species.

Deep UV Raman spectroscopy for planetary exploration: The search for in situ organics

NASA Astrophysics Data System (ADS)

Abbey, William J.; Bhartia, Rohit; Beegle, Luther W.; DeFlores, Lauren; Paez, Veronica; Sijapati, Kripa; Sijapati, Shakher; Williford, Kenneth; Tuite, Michael; Hug, William; Reid, Ray

2017-07-01

Raman spectroscopy has emerged as a powerful, non-contact, non-destructive technique for detection and characterization of in situ organic compounds. Excitation using deep UV wavelengths (< 250 nm), in particular, offers the benefits of spectra obtained in a largely fluorescence-free region while taking advantage of signal enhancing resonance Raman effects for key classes of organic compounds, such as the aromatics. In order to demonstrate the utility of this technique for planetary exploration and astrobiological applications, we interrogated three sets of samples using a custom built Raman instrument equipped with a deep UV (248.6 nm) excitation source. The sample sets included: (1) the Mojave Mars Simulant, a well characterized basaltic sample used as an analog for Martian regolith, in which we detected ∼0.04 wt% of condensed carbon; (2) a suite of organic (aromatic hydrocarbons, carboxylic acids, and amino acids) and astrobiologically relevant inorganic (sulfates, carbonates, phosphates, nitrates and perchlorate) standards, many of which have not had deep UV Raman spectra in the solid phase previously reported in the literature; and (3) Mojave Mars Simulant spiked with a representative selection of these standards, at a concentration of 1 wt%, in order to investigate natural 'real world' matrix effects. We were able to resolve all of the standards tested at this concentration. Some compounds, such as the aromatic hydrocarbons, have especially strong signals due to resonance effects even when present in trace amounts. Phenanthrene, one of the aromatic hydrocarbons, was also examined at a concentration of 0.1 wt% and even at this level was found to have a strong signal-to-noise ratio. It should be noted that the instrument utilized in this study was designed to approximate the operation of a 'fieldable' spectrometer in order to test astrobiological applications both here on Earth as well as for current and future planetary missions. It is the foundation of SHERLOC, an arm mounted instrument recently selected by NASA to fly on the next rover mission to Mars in 2020.

Assessment of Gamma Radiation Resistance of Spores Isolated from the Spacecraft Assembly Facility During MSL Assembly

NASA Technical Reports Server (NTRS)

Chopra, Arsh; Ramirez, Gustavo A.; Venkateswaran, Kasthuri J.; Vaishampayan, Parag A.

2011-01-01

Spore forming bacteria, a common inhabitant of spacecraft assembly facilities, are known to tolerate extreme environmental conditions such as radiation, desiccation, and high temperatures. Since the Viking era (early 1970's), spores have been utilized to assess the degree and level of microbiological contamination on spacecraft and their associated spacecraft assembly facilities. There is a growing concern that desiccation and extreme radiation resistant spore forming microorganisms associated with spacecraft surfaces can withstand space environmental conditions and subsequently proliferate on another solar body. Such forward contamination would certainly jeopardize future life detection or sample return technologies. It is important to recognize that different classes of organisms are critical while calculating the probability of contamination, and methods must be devised to estimate their abundances. Microorganisms can be categorized based on radiation sensitivity as Type A, B, C, and D. Type C represents spores resistant to radiation (10% or greater survival above 0.8 mRad gamma radiation). To address these questions we have purified 96 spore formers, isolated during planetary protection efforts of Mars Science Laboratory assembly for gamma radiation resistance. The spores purified and stored will be used to generate data that can be used further to model and predict the probability of forward contamination.

Assessment of Gamma Radiation Resistance of Spores Isolated from the Spacecraft Assembly Facility During MSL Assembly

NASA Technical Reports Server (NTRS)

Chopra, Arsh; Ramirez, Gustavo A.; Vaishampayan, Parag A.; Venkateswaran, Kasthuri J.

2011-01-01

Spore forming bacteria, a common inhabitant of spacecraft assembly facilities, are known to tolerate extreme environmental conditions such as radiation, desiccation, and high temperatures. Since the Viking era (early 1970's), spores have been utilized to assess the degree and level of microbiological contamination on spacecraft and their associated spacecraft assembly facilities. There is a growing concern that desiccation and extreme radiation resistant spore forming microorganisms associated with spacecraft surfaces can withstand space environmental conditions and subsequently proliferate on another solar body. Such forward contamination would certainly jeopardize future life detection or sample return technologies. It is important to recognize that different classes of organisms are critical while calculating the probability of contamination, and methods must be devised to estimate their abundances. Microorganisms can be categorized based on radiation sensitivity as Type A, B, C, and D. Type C represents spores resistant to radiation (10% or greater survival above 0.8 Mrad gamma radiation). To address these questions we have purified 96 spore formers, isolated during planetary protection efforts of Mars Science Laboratory assembly for gamma radiation resistance. The spores purified and stored will be used to generate data that can be used further to model and predict the probability of forward contamination.

Endogeneous sources: atmospheric organic syntheses, tholins and ground trust

NASA Astrophysics Data System (ADS)

Raulin, F.; Bernard, J.; Coll, P.; Nna Mvondo, D.; Ramirez, S.; Navarro-Gonzalez, R.

From the many simulation experiments which have been carried out for the last 50 years on gas phase organic synthesis but also from several theoretical modeling works, it is clear today that in situ production of organic molecules in planetary atmosphere is efficient only if the starting atmosphere is chemically reduced. In that case many simple organics can be produced like formaldehyde, (HCHO), hydrogen cyanide (HCN), cyanoacetylene (HC3N) and other nitriles, but also more complex refractory organics - usually named "tholins" - are obtained. Those tholins are still of very poorly known composition, but are of great exobiological interest since they are the precursors of many compounds of biological interest, in particular amino acids, purines and pyrimidines bases. How realistic are those experimental as well as theoretical simulations? The many planetary data which have been obtained until now on the so diversified planetary atmospheres of the solar system provide a fantastic opportunity to answer such question and validate the laboratory data with "ground trust". Indeed, at the exception of the Earth atmosphere (in which Life is the essential source of organics), any organic compound has been detected in the inner planets. On the contrary, all the outer planets, from Jupiter to Neptune (and even Pluto) involve organic chemical processes, through the chemistry of their atmosphere, and methane photochemistry. They are also present in the dense atmosphere of Titan, the largest satellite of Saturn, (in the gas and aerosol phases), in the much thinner atmosphere of Triton, the largest satellite of Neptune (mainly in the solid phase, on its surface), and on the surface of many of the other satellites of the outer planets. Thus, although we have so far no real direct evidence for this assumption, laboratory data strongly suggest that extraterrestrial organic chemistry systematically involves tholins-like matter. The different aspects of extraterrestrial atmospheric organic chemistry will be presented and discussed, on the basis of recent laboratory data, in particular from simulation experiments related to oxidized and reduced atmospheres and planetary observations.

Driving Forces of the Self-Assembly of Supramolecular Systems: Partially Ordered Mesophases

NASA Astrophysics Data System (ADS)

Shcherbina, M. A.; Chvalun, S. N.

2018-06-01

The main aspects are considered of the self-organization of a new class of liquid crystalline compounds, rigid sector-shaped and cone-shaped dendrons. Theoretical approaches to the self-assembly of different amphiphilic compounds (lipids, bolaamphiphiles, block copolymers, and polyelectrolytes) are described. Particular attention is given to the mesophase structures that emerge during the self-organization of mesophases characterized by intermediate degrees of ordering, e.g., plastic crystals, the rotation-crystalline phase in polymers, ordered and disordered two-dimensional columnar phases, and bicontinuous cubic phases of different symmetry.

NASA's Planetary Science Missions and Participations

NASA Astrophysics Data System (ADS)

Daou, Doris; Green, James L.

2017-04-01

NASA's Planetary Science Division (PSD) and space agencies around the world are collaborating on an extensive array of missions exploring our solar system. Planetary science missions are conducted by some of the most sophisticated robots ever built. International collaboration is an essential part of what we do. NASA has always encouraged international participation on our missions both strategic (ie: Mars 2020) and competitive (ie: Discovery and New Frontiers) and other Space Agencies have reciprocated and invited NASA investigators to participate in their missions. NASA PSD has partnerships with virtually every major space agency. For example, NASA has had a long and very fruitful collaboration with ESA. ESA has been involved in the Cassini mission and, currently, NASA funded scientists are involved in the Rosetta mission (3 full instruments, part of another), BepiColombo mission (1 instrument in the Italian Space Agency's instrument suite), and the Jupiter Icy Moon Explorer mission (1 instrument and parts of two others). In concert with ESA's Mars missions NASA has an instrument on the Mars Express mission, the orbit-ground communications package on the Trace Gas Orbiter (launched in March 2016) and part of the DLR/Mars Organic Molecule Analyzer instruments going onboard the ExoMars Rover (to be launched in 2018). NASA's Planetary Science Division has continuously provided its U.S. planetary science community with opportunities to include international participation on NASA missions too. For example, NASA's Discovery and New Frontiers Programs provide U.S. scientists the opportunity to assemble international teams and design exciting, focused planetary science investigations that would deepen the knowledge of our Solar System. The PSD put out an international call for instruments on the Mars 2020 mission. This procurement led to the selection of Spain and Norway scientist leading two instruments and French scientists providing a significant portion of another instrument. This was a tremendously successful activity leading to another similar call for instrument proposals for the Europa mission. Europa mission instruments will be used to conduct high priority scientific investigations addressing the science goals for the moon's exploration outlined in the National Resource Council's Planetary Decadal Survey, Vision and Voyages (2011). International partnerships are an excellent, proven way of amplifying the scope and sharing the science results of a mission otherwise implemented by an individual space agency. The exploration of the Solar System is uniquely poised to bring planetary scientists, worldwide, together under the common theme of understanding the origin, evolution, and bodies of our solar neighborhood. In the past decade we have witnessed great examples of international partnerships that made various missions the success they are known for today. The Planetary Science Division at NASA continues to seek cooperation with our strong international partners in support of planetary missions.

Nonconsumable electrode assembly and use thereof for the electrolytic production of metals and silicon

DOEpatents

Byrne, Stephen C.; Ray, Siba P.

1984-01-01

A nonconsumable electrode assembly suitable for use in the production of metal by electrolytic reduction of a metal compound dissolved in a molten salt, the assembly comprising a metal conductor attached to a ceramic electrode body by a metal bond on a portion of the body having a level of free metal or metal alloy sufficient to effect a metal bond.

Stoichiometric Control of Multiple Different Tectons in Coordination-Driven Self-assembly

PubMed Central

Lee, Junseong; Ghosh, Koushik; Stang, Peter J.

2009-01-01

We present a general strategy for the synthesis of stable, multi-component fused polygon complexes where coordination-driven self-assembly allows for single supramolecular species can be formed from multi-component self-assembly and the shape of the obtained polygons can be controlled by simply changing the ratio of individual components. The compounds are characterized by Multinuclear NMR, ESI Mass spectrometry. PMID:19663439

Using the ISS as a Testbed to Prepare for the Next Generation of Space-Based Telescopes

NASA Technical Reports Server (NTRS)

Ess, Kim; Thronson, Harley; Boyles, Mark; Sparks, William; Postman, Marc; Carpenter, Kenneth

2012-01-01

The ISS provides a unique opportunity to develop the technologies and operational capabilities necessary to assemble future large space telescopes that may be used to investigate planetary systems around neighboring stars. Assembling telescopes in space is a paradigm-shifting approach to space astronomy. Using the ISS as a testbed will reduce the technical risks of implementing this major scientific facility, such as laser metrology and wavefront sensing and control (WFSC). The Optical Testbed and Integration on ISS eXperiment (OpTIIX) will demonstrate the robotic assembly of major components, including the primary and secondary mirrors, to mechanical tolerances using existing ISS infrastructure, and the alignment of the optical elements to a diffraction-limited optical system in space. Assembling the optical system and removing and replacing components via existing ISS capabilities, such as the Special Purpose Dexterous Manipulator (SPDM) or the ISS flight crew, allows for future experimentation and repair, if necessary. First flight on ISS for OpTIIX, a small 1.5 meter optical telescope, is planned for 2015. In addition to demonstration of key risk-retiring technologies, the OpTIIX program includes a public outreach program to show the broad value of ISS utilization.

A versatile system for biological and soil chemical tests on a planetary landing craft. I - Scientific objectives

NASA Technical Reports Server (NTRS)

Radmer, R. J.; Kok, B.; Martin, J. P.

1976-01-01

We describe an approach for the remote detection and characterization of life in planetary soil samples. A mass spectrometer is used as the central sensor to monitor changes in the gas phase in eleven test cells filled with soil. Many biological assays, ranging from general 'in situ' assays to specific metabolic processes (such as photosynthesis, respiration, denitrification, etc.) can be performed by appropriate additions to the test cell via attached preloaded injector capsules. The system is also compatible with a number of chemical assays such as the analysis of atmospheric composition (both chemical and isotopic), the status of soil water, and the determination of compounds of carbon, nitrogen and sulfur in the soil.

Electrochemical cell and method of assembly

DOEpatents

Shimotake, Hiroshi; Voss, Ernst C. H.; Bartholme, Louis G.

1979-01-01

A method of preparing an electrochemical cell is disclosed which permits the assembly to be accomplished in air. The cell includes a metal sulfide as the positive electrode reactant, lithium alloy as the negative electrode reactant and an alkali metal, molten salt electrolyte. Positive electrode reactant is introduced as Li.sub.2 FeS.sub.2, a single-phase compound produced by the reaction of Li.sub.2 S and FeS. The use of this compound permits introduction of lithium in an oxidized form. Additional lithium can be introduced in the negative electrode structure enclosed within an aluminum foil envelope between layers of porous aluminum. Molten salt electrolyte is added after assembly and evacuation of the cell by including an interelectrode separator that has been prewet with an organic solution of KCl.

STS-30 Magellan spacecraft arrives at KSC after six-day journey from Colorado

NASA Technical Reports Server (NTRS)

1989-01-01

The Payload Environmental Transportation System (PETS) (semi-truck and trailer), which transported the Magellan spacecraft on its six-day journey from Martin Marietta in Denver, Colorado, to Kennedy Space Center (KSC), arrives safely at the Space Assembly and Encapsulation Facility 2 (SAEF-2) planetary checkout facility. The spacecraft, destined for unprecedented studies of Venusian topographic features, is to be deployed by the crew of NASA's STS-30 mission in April 1989. View provided by KSC with alternate number KSC-88PC-1082.

Prebiotic chemistry in space; Proceedings of Symposia B1.4 and F3.3 of the COSPAR Scientific Assembly, 30th, Hamburg, Germany, July 11-21, 1994

NASA Technical Reports Server (NTRS)

1994-01-01

A two-part symposium was held concerning topics in Solar System chemistry. The first part covered the organic chemistry ofsmall bodies of the interplanetray medium. It produced papers on the evolution, spectral properties and composition of organic matter in comets, interplanetary dust and asteroids. The second part covered cryochemistry and exobiology in planetary atmospheres (gas giant planets and their satellites) and in various astronomical ices.

Space Station services and design features for users

NASA Technical Reports Server (NTRS)

Kurzhals, Peter R.; Mckinney, Royce L.

1987-01-01

The operational design features and services planned for the NASA Space Station will furnish, in addition to novel opportunities and facilities, lower costs through interface standardization and automation and faster access by means of computer-aided integration and control processes. By furnishing a basis for large-scale space exploitation, the Space Station will possess industrial production and operational services capabilities that may be used by the private sector for commercial ventures; it could also ultimately support lunar and planetary exploration spacecraft assembly and launch facilities.

End-group-directed self-assembly of organic compounds useful for photovoltaic applications

DOEpatents

Beaujuge, Pierre M.; Lee, Olivia P.; Yiu, Alan T.; Frechet, Jean M.J.

2016-05-31

The present invention provides for an organic compound comprising electron deficient unit covalently linked to two or more electron rich units. The present invention also provides for a device comprising the organic compound, such as a light-emitting diode, thin-film transistor, chemical biosensor, non-emissive electrochromic, memory device, photovoltaic cells, or the like.

Parachute Swivel Mechanism for planetary entry

NASA Technical Reports Server (NTRS)

Birner, R.; Kaese, J.; Koller, F.; Muehlner, E.; Luhmann, H.-J.

1993-01-01

A parachute swivel mechanism (PSM) for planetary entry missions such as a Mars probe (MARSNET) or return of cometary material samples (ROSETTA mission) has been developed. The purpose of the PSM is to decouple the spin of the probe from the parachute, with low friction torque, during both the deployment and descent phases. Critical requirements are high shock loads, low friction, low temperatures, and several years of storage in the deep space environment (during the cruise phase of the probe, prior to operation). The design uses a main thrust ball bearing to cope with the load requirement and a smaller thrust ball bearing for guiding of the shaft. Except for use on the Viking and Galileo swivels, it appears that this type of bearing has very rarely been employed in space mechanisms, so that little is known of its friction behavior with dry lubrication. A slip ring assembly allows the transfer of electrical power for post-reefing of the parachute. A test program has been conducted covering the environmental conditions of Mars entry and Earth reentry. This paper describes requirement constraints, model missions of planetary entries, a bearing trade-off, analyses performed, design details, the lubrication system, and test results (friction torque versus load/spin rate). In addition, the design of the test rig is addressed.

Implementing planetary protection measures on the Mars Science Laboratory.

PubMed

Benardini, James N; La Duc, Myron T; Beaudet, Robert A; Koukol, Robert

2014-01-01

The Mars Science Laboratory (MSL), comprising a cruise stage; an aeroshell; an entry, descent, and landing system; and the radioisotope thermoelectric generator-powered Curiosity rover, made history with its unprecedented sky crane landing on Mars on August 6, 2012. The mission's primary science objective has been to explore the area surrounding Gale Crater and assess its habitability for past life. Because microbial contamination could profoundly impact the integrity of the mission and compliance with international treaty was required, planetary protection measures were implemented on MSL hardware to verify that bioburden levels complied with NASA regulations. By applying the proper antimicrobial countermeasures throughout all phases of assembly, the total bacterial endospore burden of MSL at the time of launch was kept to 2.78×10⁵ spores, well within the required specification of less than 5.0×10⁵ spores. The total spore burden of the exposed surfaces of the landed MSL hardware was 5.64×10⁴, well below the allowed limit of 3.0×10⁵ spores. At the time of launch, the MSL spacecraft was burdened with an average of 22 spores/m², which included both planned landed and planned impacted hardware. Here, we report the results of a campaign to implement and verify planetary protection measures on the MSL flight system.

Earth-based analogs of lunar and planetary facilities

NASA Technical Reports Server (NTRS)

Bell, Larry; Trotti, Guillermo

1992-01-01

Antarctica contains areas where the environment and terrain are more similar to regions on the Moon and Mars than any other place on Earth. These features offer opportunities for simulations to determine performance capabilities of people and machines in harsh, isolated locales. The Sasakawa International Center for Space Architecture (SICSA) plans to create a facility on Antarctica for research, planning, and demonstrations in support of planetary exploration. The Antarctic Planetary Testbed (APT) will be financed and utilized by public and private organizations throughout the world. Established on a continent owned by no country, it can serve as a model for cooperation between spacefaring nations. APT science and technology programs will expand knowledge about the nature and origin of our solar system, and will support preparations for human settlements beyond Earth that may occur within the first quarter of the next century. The initial APT facility, conceived to be operational by the year 1992, will be constructed during the summer months by a crew of approximately 12. Six to eight of these people will remain through the winter. As in space, structures and equipment systems will be modular to facilitate efficient transport to the site, assembly, and evolutionary expansion. State-of-the-art waste recovery/recycling systems are also emphasized due to their importance in space.

Planet Formation Imager (PFI): science vision and key requirements

NASA Astrophysics Data System (ADS)

Kraus, Stefan; Monnier, John D.; Ireland, Michael J.; Duchêne, Gaspard; Espaillat, Catherine; Hönig, Sebastian; Juhasz, Attila; Mordasini, Chris; Olofsson, Johan; Paladini, Claudia; Stassun, Keivan; Turner, Neal; Vasisht, Gautam; Harries, Tim J.; Bate, Matthew R.; Gonzalez, Jean-François; Matter, Alexis; Zhu, Zhaohuan; Panic, Olja; Regaly, Zsolt; Morbidelli, Alessandro; Meru, Farzana; Wolf, Sebastian; Ilee, John; Berger, Jean-Philippe; Zhao, Ming; Kral, Quentin; Morlok, Andreas; Bonsor, Amy; Ciardi, David; Kane, Stephen R.; Kratter, Kaitlin; Laughlin, Greg; Pepper, Joshua; Raymond, Sean; Labadie, Lucas; Nelson, Richard P.; Weigelt, Gerd; ten Brummelaar, Theo; Pierens, Arnaud; Oudmaijer, Rene; Kley, Wilhelm; Pope, Benjamin; Jensen, Eric L. N.; Bayo, Amelia; Smith, Michael; Boyajian, Tabetha; Quiroga-Nuñez, Luis Henry; Millan-Gabet, Rafael; Chiavassa, Andrea; Gallenne, Alexandre; Reynolds, Mark; de Wit, Willem-Jan; Wittkowski, Markus; Millour, Florentin; Gandhi, Poshak; Ramos Almeida, Cristina; Alonso Herrero, Almudena; Packham, Chris; Kishimoto, Makoto; Tristram, Konrad R. W.; Pott, Jörg-Uwe; Surdej, Jean; Buscher, David; Haniff, Chris; Lacour, Sylvestre; Petrov, Romain; Ridgway, Steve; Tuthill, Peter; van Belle, Gerard; Armitage, Phil; Baruteau, Clement; Benisty, Myriam; Bitsch, Bertram; Paardekooper, Sijme-Jan; Pinte, Christophe; Masset, Frederic; Rosotti, Giovanni

2016-08-01

The Planet Formation Imager (PFI) project aims to provide a strong scientific vision for ground-based optical astronomy beyond the upcoming generation of Extremely Large Telescopes. We make the case that a breakthrough in angular resolution imaging capabilities is required in order to unravel the processes involved in planet formation. PFI will be optimised to provide a complete census of the protoplanet population at all stellocentric radii and over the age range from 0.1 to 100 Myr. Within this age period, planetary systems undergo dramatic changes and the final architecture of planetary systems is determined. Our goal is to study the planetary birth on the natural spatial scale where the material is assembled, which is the "Hill Sphere" of the forming planet, and to characterise the protoplanetary cores by measuring their masses and physical properties. Our science working group has investigated the observational characteristics of these young protoplanets as well as the migration mechanisms that might alter the system architecture. We simulated the imprints that the planets leave in the disk and study how PFI could revolutionise areas ranging from exoplanet to extragalactic science. In this contribution we outline the key science drivers of PFI and discuss the requirements that will guide the technology choices, the site selection, and potential science/technology tradeoffs.

Evolving directions in NASA's planetary rover requirements and technology

NASA Technical Reports Server (NTRS)

Weisbin, C. R.; Montemerlo, Mel; Whittaker, W.

1993-01-01

The evolution of NASA's planning for planetary rovers (that is robotic vehicles which may be deployed on planetary bodies for exploration, science analysis, and construction) and some of the technology that was developed to achieve the desired capabilities is reviewed. The program is comprised of a variety of vehicle sizes and types in order to accommodate a range of potential user needs. This includes vehicles whose weight spans a few kilograms to several thousand kilograms; whose locomotion is implemented using wheels, tracks, and legs; and whose payloads vary from microinstruments to large scale assemblies for construction. Robotic vehicles and their associated control systems, developed in the late 1980's as part of a proposed Mars Rover Sample Return (MRSR) mission, are described. Goals suggested at the time for such a MRSR mission included navigating for one to two years across hundreds of kilometers of Martian surface; traversing a diversity of rugged, unknown terrain; collecting and analyzing a variety of samples; and bringing back selected samples to the lander for return to Earth. Current plans (considerably more modest) which have evolved both from technological 'lessons learned' in the previous period, and modified aspirations of NASA missions are presented. Some of the demonstrated capabilities of the developed machines and the technologies which made these capabilities possible are described.

The James Webb Space Telescope

NASA Technical Reports Server (NTRS)

Gardner, Jonathan P.

2011-01-01

The James Webb Space Telescope is the scientific successor to the Hubble and Spitzer Space Telescopes, and is currently the largest scientific project under construction in the United States. It will be a large (6.6m) cold (50K) telescope launched in about 5 years into orbit around the second Earth-Sun Lagrange point. It is a partnership of NASA with the European and Canadian Space Agencies. Science with the James Webb Space Telescope falls into four themes. The End of the Dark Ages: First Light and Reionization theme seeks to identify the first luminous sources to form and to determine the ionization history of the universe. The Assembly of Galaxies theme seeks to determine how galaxies and the dark matter, gas, stars, metals, morphological structures, and black holes within them evolved from the epoch of reionization to the present. The Birth of Stars and Proto planetary Systems theme seeks to unravel the birth and early evolution of stars, from infall onto dust-enshrouded protostars, to the genesis of planetary systems. The Planetary Systems and the Origins of Life theme seeks to determine the physical and chemical properties of planetary systems around nearby stars and of our own, and investigate the potential for life in those systems. Webb will have four instruments: The Near-Infrared Camera, the Near-Infrared multi-object Spectrograph, and the Tunable Filter Imager will cover the wavelength range 0.6 to 5 microns, while the Mid-Infrared Instrument will do both imaging and spectroscopy from 5 to 28.5 microns. I will conclude the talk with a description of recent technical progress in the construction of the observatory.

Carbon Dioxide: The Other Planetary Fluid

NASA Astrophysics Data System (ADS)

Glaser, S.; Gamez, D.; Shock, E.

2016-12-01

Cometary and interstellar ices have carbon dioxide to water mole ratios of up to 0.3. When melted, such high levels of carbon dioxide cannot all be dissolved in the aqueous phase and instead partition into a CO2-rich (carbonic) fluid. This implies that during the accretion and formation of planetary systems carbonic fluids are not only possible, but common. In fact, they make up the atmosphere of Venus, are found bubbling out of Champagne Vent in the Pacific Ocean, and are documented by metamorphic fluid inclusions. Examination of phase diagrams reveals the conditions where carbonic fluids will exist or predominate. Carbonic fluids are predicted to exist in Earth's subduction zones and under the ice of small ocean worlds. CO2 had previously been shown to completely dissolve into NH­­3­-H­­2O oceans on small icy bodies by forming ammonium carbonate, but the newer measurements of CO2­ abundances indicate that not all of the CO2 can partition into the aqueous fluid as ammonium carbonate. The remaining CO2 would necessarily form a separate carbonic fluid making it likely that liquid CO2 would be a major oceanic component on some small icy bodies. The enhanced solubility of nonpolar and slightly polar organic compounds in carbonic fluids relative to aqueous fluids means that generation, transport, and deposition processes can be greatly enhanced in those cases where carbonic fluids occur. As an example, the solubility of benzoic acid, a polar compound, is about an order of magnitude greater in carbonic than in aqueous fluids, which is surprising given that water is a polar solvent and carbon dioxide is a nonpolar solvent. Anthracene, a nonpolar compound, has an even greater solubility difference between carbonic and aqueous fluids at approximately four orders of magnitude. Highly polar compounds, including most of the building blocks of life, are more soluble in aqueous fluids than in carbonic fluids. The solubility difference of organic molecules in carbonic fluids relative to aqueous fluids determines the distribution of the building blocks of life in planetary systems. Partitioning of organics into a carbonic fluid may be the mechanism of removing biochemically irrelevant molecules from the aqueous phase and enabling the emergence of life.

Biology and The Future of Mars

NASA Technical Reports Server (NTRS)

McKay, Christopher P.

2004-01-01

It is possible that at some time in the future we might recreate a habitable climate on Mars returning it to the life-bearing state it may have enjoyed early in its history. Our studies of Mars are still in a preliminary state but everything we have learned suggests that it may he possible to restore Mars to a habitable climate. Long part of the intersection of science and fiction (eg. Clarke, 1995), serious studies of planetary ecosynthesis on Mars began after the results of the Viking mission indicated that all the compounds needed for life were present on the surface of Mars is some accessible form (Averner and MacElroy, 1976; McKay et al., 1991; Fogg, 1995). Recent work has focused on the use of climate models to compute the timescales to warm Mars (McKay et al., 1991 ; McKay and Marinova, 2001). Planetary ecosynthesis on Mars has implications for the objectives and conduct of robotic and human exploration. In particular the question of forward contamination must be considered in a new way if we wish to control the introduction of life to Mars in advance of planetary ecosynthesis.

A unified model of bedforms in water, Earth and other planetary bodies

NASA Astrophysics Data System (ADS)

Duran Vinent, O.; Claudin, P.; Winter, C.; Andreotti, B.

2017-12-01

The emergence of bedforms as result of the coupling between a fluid flow and sediment transport is a remarkable example of self-organized natural patterns. Subaqueous bedforms generated by unidirectional water flows, like ripples, dunes or compound bedforms, have been shown to depend on grain size, water depth and flow velocity. However, this variety of morphologies, empirically classified according to their size, is still not understood in terms of mechanical and hydrodynamical mechanisms. We present a process-based model that simultaneously explain the scaling of bedforms for Water, Air, Mars and Venus, and can be potentially applied to other planetary bodies such as Titan or Pluto. The model couples hydrodynamics over a modulated bed to sediment transport and relaxation laws, and resolves pattern coarsening from initial to mature bedforms. We find two fundamental types of bedforms, called `laminar' and `turbulent' and analogous to water ripples and dunes, and the conditions leading to their formation. By relating morphology to hydrodynamic and sediment transport details, our model opens the way to extract hydrodynamic information from the stratigraphy record and shed a light to past and current planetary conditions.

Assembly of Four Diverse Heterocyclic Libraries Enabled by Prins Cyclization, Au-Catalyzed Enyne Cycloisomerization, and Automated Amide Synthesis

PubMed Central

Cui, Jiayue; Chai, David I.; Miller, Christopher; Hao, Jason; Thomas, Christopher; Wang, JingQi; Scheidt, Karl A.; Kozmin, Sergey A.

2013-01-01

We describe a unified synthetic strategy for efficient assembly of four new heterocyclic libraries. The synthesis began by creating a range of structurally diverse pyrrolidinones or piperidinones. Such compounds were obtained in a simple one-flask operation starting with readily available amines, ketoesters, and unsaturated anhydrides. The use of tetrahydropyran-containing ketoesters, which were rapidly assembled by our Prins cyclization protocol, enabled efficient fusion of pyran and piperidinone cores. A newly developed Au(I)-catalyzed cycloisomerization of alkyne-containing enamides further expanded heterocyclic diversity by providing rapid entry into a wide range of bicyclic and tricyclic dienamides. The final stage of the process entailed diversification of each of the initially produced carboxylic acids using a fully automated platform for amide synthesis, which delivered 1872 compounds in high diastereomeric and chemical purity. PMID:22860634

Probing planetary interiors: Shock compression of water to 700 GPa and 3.8 g/cc, and recent high precision Hugoniot measurements of deuterium

NASA Astrophysics Data System (ADS)

Knudson, Marcus

2013-06-01

The past several years have seen tremendous increase in the number of identified extra-solar planetary systems. Our understanding of the formation of these systems is tied to our understanding of the internal structure of these exoplanets, which in turn rely upon equations of state of light elements and compounds such as water and hydrogen. Here we present shock compression data for water with unprecedented accuracy that shows commonly used models for water in planetary modeling significantly overestimate the compressibility at conditions relevant to planetary interiors. Furthermore, we show that its behavior at these conditions, including reflectivity and isentropic response, is well described by a recent first-principles based equation of state. These findings advocate the use of this model as the standard for modeling Neptune, Uranus, and ``hot Neptune'' exoplanets, and should contribute to improved understanding of the interior structure of these planets, and perhaps improved understanding of formation mechanisms of planetary systems. We also present very recent experiments on deuterium that have taken advantage of continued improvements in both experimental configuration and the understanding of the quartz shock standard to obtain Hugoniot data with a significant increase in precision. These data will prove to provide a stringent test for the equation of state of hydrogen and its isotopes. Sandia is a multiprogram laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Company, for the US Department of Energy's National Nuclear Security Administration under Contract No. DE-ACO4-94AL85000.

Planetary and Space Simulation Facilities PSI at DLR for Astrobiology

NASA Astrophysics Data System (ADS)

Rabbow, E.; Rettberg, P.; Panitz, C.; Reitz, G.

2008-09-01

Ground based experiments, conducted in the controlled planetary and space environment simulation facilities PSI at DLR, are used to investigate astrobiological questions and to complement the corresponding experiments in LEO, for example on free flying satellites or on space exposure platforms on the ISS. In-orbit exposure facilities can only accommodate a limited number of experiments for exposure to space parameters like high vacuum, intense radiation of galactic and solar origin and microgravity, sometimes also technically adapted to simulate extraterrestrial planetary conditions like those on Mars. Ground based experiments in carefully equipped and monitored simulation facilities allow the investigation of the effects of simulated single environmental parameters and selected combinations on a much wider variety of samples. In PSI at DLR, international science consortia performed astrobiological investigations and space experiment preparations, exposing organic compounds and a wide range of microorganisms, reaching from bacterial spores to complex microbial communities, lichens and even animals like tardigrades to simulated planetary or space environment parameters in pursuit of exobiological questions on the resistance to extreme environments and the origin and distribution of life. The Planetary and Space Simulation Facilities PSI of the Institute of Aerospace Medicine at DLR in Köln, Germany, providing high vacuum of controlled residual composition, ionizing radiation of a X-ray tube, polychromatic UV radiation in the range of 170-400 nm, VIS and IR or individual monochromatic UV wavelengths, and temperature regulation from -20°C to +80°C at the sample size individually or in selected combinations in 9 modular facilities of varying sizes are presented with selected experiments performed within.

Planetary Ices and the Linear Mixing Approximation

DOE PAGES

Bethkenhagen, M.; Meyer, Edmund Richard; Hamel, S.; ...

2017-10-10

Here, the validity of the widely used linear mixing approximation (LMA) for the equations of state (EOSs) of planetary ices is investigated at pressure–temperature conditions typical for the interiors of Uranus and Neptune. The basis of this study is ab initio data ranging up to 1000 GPa and 20,000 K, calculated via density functional theory molecular dynamics simulations. In particular, we determine a new EOS for methane and EOS data for the 1:1 binary mixtures of methane, ammonia, and water, as well as their 2:1:4 ternary mixture. Additionally, the self-diffusion coefficients in the ternary mixture are calculated along three different Uranus interior profiles and compared to the values of the pure compounds. We find that deviations of the LMA from the results of the real mixture are generally small; for the thermal EOSs they amount to 4% or less. The diffusion coefficients in the mixture agree with those of the pure compounds within 20% or better. Finally, a new adiabatic model of Uranus with an inner layer of almost pure ices is developed. The model is consistent with the gravity field data and results in a rather cold interior (more » $${T}_{\\mathrm{core}}\\sim 4000$$ K).« less

Final Approval of California Air Plan Revision; Antelope Valley Air Quality Management District; VOCs From Motor Vehicle Assembly Coating Operations

EPA Pesticide Factsheets

EPA is taking final action to approve a revision to the Antelope Valley Air Quality Management District (AVAQMD) portion of the California SIP concerning the emissions of volatile organic compounds (VOCs) from motor vehicle assembly coating operations.

Nanotrumpets and circularly polarized luminescent nanotwists hierarchically self-assembled from an achiral C3-symmetric ester.

PubMed

Sang, Yutao; Duan, Pengfei; Liu, Minghua

2018-04-17

An achiral C3-symmetric molecule was found to self-assemble into various hierarchical nanostructures such as nanotwists, nanotrumpets and nanobelts, in which the twisted fibers showed supramolecular chirality as well as circularly polarized luminescence although the compound is achiral.

Stoichiometric control of multiple different tectons in coordination-driven self-assembly: preparation of fused metallacyclic polygons.

PubMed

Lee, Junseong; Ghosh, Koushik; Stang, Peter J

2009-09-02

We present a general strategy for the synthesis of stable, multicomponent fused polygon complexes in which coordination-driven self-assembly allows for single supramolecular species to be formed from multicomponent self-assembly and the shape of the obtained polygons can be controlled simply by changing the ratio of individual components. The compounds have been characterized by multinuclear NMR spectroscopy and electrospray ionization mass spectrometry.

Green Synthetic Alternatives to Organic Compounds and Nanomaterials

EPA Science Inventory

A brief account of reactions involving microwave (MW) exposure of neat reactants or catalyzed by mineral support surfaces, such as alumina, silica, clay, or their ‘doped’ versions, for the rapid one-pot assembly of heterocyclic compounds from in situ generated reactive intermedia...

Self-assembling cyclic systems as drug carriers

NASA Astrophysics Data System (ADS)

Banerjee, A.; Yadav, A.

2013-12-01

Self-assembling cyclic systems have been of interest to researchers for over a decade now, and their wide variety applications have been explored from electronic devices to medicinal purposes. But still their discovery for newer innovative applications remains as valuable as before. In this study, ab initio Hartree-Fock molecular orbital calculations have been performed on peptidic and peptidomimetic cyclic compounds to identify characteristics required in compounds for efficient self-aggregation. The effect of these characteristics in determining the pore size and length of nanotube has been studied. Effect of backbone and substituents on environment of outer and inner surface and carriage properties has been studied in detail. Self-aggregating compounds (Ala)12 and (Ala)10 have been predicted to form a tubular structure with dimensions in nanoscale. They have been predicted to work as novel drug carriers having inert outer wall and inner pore. A peptidic self-aggregating compound (Ala)12 has been studied and suggested as carrier for antibiotic gentamicin to exemplify carriage properties of the designed compound. Such novel self-aggregatory systems are expected to help simplify the drug delivery process and increase bioavailability of various drugs.

Spectral properties of condensed phases of disulfur monoxide, polysulfur oxide, and irradiated sulfur. [in planetary atmospheres

NASA Technical Reports Server (NTRS)

Hapke, Bruce; Graham, Francis

1989-01-01

The spectral reflectances of S2O, as well as the polysulfur oxide (PSO) condensate dissociation products of SO2 and condensates of elemental sulfur irradiated with UV light and X-rays, have been ascertained in the 200-1700 nm range with a view to the relevance of these compounds to the interpretation of planetary data. While S2O is a dark red solid, PSO is a pale yellow one that absorbs strongly in the UV but exhibits no bands in either the visible or near IR. Elemental S produces strong bands in the UV, and while it is normally white at room temperature, UV irradiation causes it to turn yellow. X-ray irradiation of S turns it orange.

Exobiology and the origin of life. [organic compounds in planetary atmospheres and interstellar matter

NASA Technical Reports Server (NTRS)

Sagan, C.

1978-01-01

Research supported wholly or in part by NASA is summarized, Topics covered include the molecular analysis of ultraviolet-photoproduced organic solids synthesized under simulated Jovian conditions; the molecular analysis of organic solids produced by electrical discharge in reducing atmospheres; the organic chemistry of interstellar grains; the spectra of possible organic solids present as aerosols in planetary atmospheres; far infrared studies of organic polymers of possible astrophysical interest; organic dust synthesized in reducing environments by ultraviolet radiation or electric discharge; the diffusion of galactic civilizations; eavesdropping on galactic civilizations; Lander imaging as a detector of life on Mars; and continuing puzzles about Mars. Bibliographic data is included for four additional publications not supported by NASA grant, but related to the objectives of the program.

Mineralogy

NASA Technical Reports Server (NTRS)

Dyar, M. Darby; Treiman, Allan; Beauchamp, Patricia; Blake, David; Blaney, Diana; Kim, Sun S.; Klingelhoefer, Goestar; Mehall, Greg; Morris, Richard; Ninkov, Zoran;

Self assembly properties of primitive organic compounds

NASA Technical Reports Server (NTRS)

Deamer, D. W.

1991-01-01

A central event in the origin of life was the self-assembly of amphiphilic, lipid-like compounds into closed microenvironments. If a primitive macromolecular replicating system could be encapsulated within a vesicular membrane, the components of the system would share the same microenvironment, and the result would be a step toward true cellular function. The goal of our research has been to determine what amphiphilic molecules might plausibly have been available on the early Earth to participate in the formation of such boundary structures. To this end, we have investigated primitive organic mixtures present in carbonaceous meteorites such as the Murchison meteorite, which contains 1-2 percent of its mass in the form of organic carbon compounds. It is likely that such compounds contributed to the inventory of organic carbon on the prebiotic earth, and were available to participate in chemical evolution leading to the emergence of the first cellular life forms. We found that Murchison components extracted into non-polar solvent systems are surface active, a clear indication of amphiphilic character. One acidic fraction self-assembles into vesicular membranes that provide permeability barriers to polar solutes. Other evidence indicates that the membranes are bimolecular layers similar to those formed by contemporary membrane lipids. We conclude that bilayer membrane formation by primitive amphiphiles on the early Earth is feasible. However, only a minor fraction of acidic amphiphiles assembles into bilayers, and the resulting membranes require narrowly defined conditions of pH and ionic composition to be stable. It seems unlikely, therefore, that meteoritic infall was a direct source of membrane amphiphiles. Instead, the hydrocarbon components and their derivatives more probably would provide an organic stock available for chemical evolution. Our current research is directed at possible reactions which would generate substantial quantities of membranogenic amphiphiles. One possibility is photochemical oxidation of hydrocarbons.

Planetary protection requirements for orbiter and netlander elements of the CNES/NASA Mars sample return mission

NASA Astrophysics Data System (ADS)

Debus, A.

In the framework of Mars exploration, particularly for missions dedicated to the search for life or for traces of ancient forms of life, NASA and CNES have decided to join their efforts in order to build a Mars sample return mission. Taking into account article IX of the OUTER SPACE TREATY (Treaty on principles governing the activities of states in the exploration and use of outer space, including the Moon and other celestial, referenced 610 UNTS 205 - resolution 2222(XXI) of December 1966, ratified in London / Washington January 27, 1967) and in order to comply with the COSPAR planetary protection recommendations, a common planetary protection program has to be established. Mars in-situ experimentations are limited by the size and the mass of the instruments necessary to perform exobiology investigations and, consequently, it appears that the best way to conduct such experiments is to bring back Mars samples to Earth. A sample return mission enables the use of a very large number of instruments and analysis protocols, giving exobiologists the best chance to find living entities or organic compounds related to life. Such a mission is complicated from a planetary protection point of view, it combines constraints for the protection of both the Mars environment as well as Earth, including the preservation of samples to ensure the validity of exobiological experiments.

Reliability of CCGA 1152 and CCGA 1272 Interconnect Packages for Extreme Thermal Environments

NASA Technical Reports Server (NTRS)

Ramesham, Rajeshuni

2013-01-01

Ceramic column grid array (CCGA) packages have been increasing in use based on their advantages of high interconnect density, very good thermal and electrical performance, and compatibility with standard surface-mount packaging assembly processes. CCGA packages are used in space applications such as in logics and microprocessor functions, telecommunications, flight avionics, and payload electronics. As these packages tend to have less solder joint strain relief than leaded packages, the reliability of CCGA packages is very important for short- and long-term space missions. Certain planetary satellites require operations of thermally uncontrolled hardware under extremely cold and hot temperatures with large diurnal temperature change from day to night. The planetary protection requires the hardware to be baked at +125 C for 72 hours to kill microbugs to avoid any biological contamination, especially for sample return missions. Therefore, the present CCGA package reliability research study has encompassed the temperature range of 185 to +125 C to cover various NASA deep space missions. Advanced 1152 and 1272 CCGA packaging interconnects technology test hardware objects have been subjected to ex treme temperature thermal cycles from 185 to +125 C. X-ray inspections of CCGA packages have been made before thermal cycling. No anomalous behavior and process problems were observed in the x-ray images. The change in resistance of the daisy-chained CCGA interconnects was measured as a function of increasing number of thermal cycles. Electrical continuity measurements of daisy chains have shown no anomalies, even until 596 thermal cycles. Optical inspections of hardware have shown a significant fatigue for CCGA 1152 packages over CCGA 1272 packages. No catastrophic failures have been observed yet in the results. Process qualification and assembly are required to optimize the CCGA assembly processes. Optical inspections of CCGA boards have been made after 258 and 596 thermal cycles. Corner columns have started showing significant fatigue per optical inspection results.

A Miniaturized Variable Pressure Scanning Electron Microscope (MVP-SEM) for the Surface of Mars: An Instrument for the Planetary Science Community

NASA Technical Reports Server (NTRS)

Edmunson, J.; Gaskin, J. A.; Danilatos, G.; Doloboff, I. J.; Effinger, M. R.; Harvey, R. P.; Jerman, G. A.; Klein-Schoder, R.; Mackie, W.; Magera, B.;

Method and apparatus for subsurface exploration

NASA Technical Reports Server (NTRS)

Wilcox, Brian (Inventor)

2002-01-01

A subsurface explorer (SSX) for exploring beneath the terrestrial surface of planetary bodies such as the Earth, Mars, or comets. This exploration activity utilizes appropriate sensors and instrument to evaluate the composition, structure, mineralogy and possibly biology of the subsurface medium, as well as perhaps the ability to return samples of that medium back to the surface. The vehicle comprises an elongated skin or body having a front end and a rear end, with a nose piece at the front end for imparting force to composition material of the planetary body. Force is provided by a hammer mechanism to the back side of a nose piece from within the body of the vehicle. In the preferred embodiment, a motor spins an intermediate shaft having two non-uniform threads along with a hammer which engages these threads with two conical rollers. A brake assembly halts the rotation of the intermediate shaft, causing the conical roller to spin down the non-uniform thread to rapidly and efficiently convert the rotational kinetic energy of the hammer into translational energy.

Mineral and Geochemical Classification From Spectroscopy/Diffraction Through Neural Networks

NASA Astrophysics Data System (ADS)

Ferralis, N.; Grossman, J.; Summons, R. E.

2017-12-01

Spectroscopy and diffraction techniques are essential for understanding structural, chemical and functional properties of geological materials for Earth and Planetary Sciences. Beyond data collection, quantitative insight relies on experimentally assembled, or computationally derived spectra. Inference on the geochemical or geophysical properties (such as crystallographic order, chemical functionality, elemental composition, etc.) of a particular geological material (mineral, organic matter, etc.) is based on fitting unknown spectra and comparing the fit with consolidated databases. The complexity of fitting highly convoluted spectra, often limits the ability to infer geochemical characteristics, and limits the throughput for extensive datasets. With the emergence of heuristic approaches to pattern recognitions though machine learning, in this work we investigate the possibility and potential of using supervised neural networks trained on available public spectroscopic database to directly infer geochemical parameters from unknown spectra. Using Raman, infrared spectroscopy and powder x-ray diffraction from the publicly available RRUFF database, we train neural network models to classify mineral and organic compounds (pure or mixtures) based on crystallographic structure from diffraction, chemical functionality, elemental composition and bonding from spectroscopy. As expected, the accuracy of the inference is strongly dependent on the quality and extent of the training data. We will identify a series of requirements and guidelines for the training dataset needed to achieve consistent high accuracy inference, along with methods to compensate for limited of data.

Self-Assembly of Prebiotic Organic Materials from Impact Events of Amino Acid Solutions

NASA Astrophysics Data System (ADS)

Goldman, Nir

2017-06-01

Proteinogenic amino acids can be produced on or delivered to a planet via abiotic sources and were consequently likely present before the emergence of life on early Earth. However, the role that these materials played in the in the emergence of life remains an open question, in part because little is known about the survivability and reactivity of astrophysical prebiotic compounds upon impact with a planetary surface. To this end, we have used a force matched semi-empirical quantum simulation method in development in our group to study oblique impacts of aqueous glycine solutions at conditions of up to 40 GPa and 3000 K. We find that these elevated conditions induce the formation of glycine-oligomeric structures with a number of different chemical moieties such as hydroxyl and amine groups diffusing on and off the C-N backbones. The C-N backbones of these structures generally remain stable during cooling and expansion, yielding relatively large three-dimensional molecules that contain a number of different functional groups and embedded bonded regions akin to oligo-peptides. Our results help determine the role of comets and other celestial bodies in both the delivery and synthesis of polypeptides and homochirality to early Earth. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

The Formation of Complex Organic Compounds in Astrophysical Ices and their Implications for Astrobiology

NASA Technical Reports Server (NTRS)

Sandford, Scott A.

2015-01-01

Ices in astrophysical environments are generally dominated by very simple molecules like H2O, CH3OH, CH4, NH3, CO, CO2, etc, although they likely contain PAHs as well. These molecules, particularly H2O, are of direct interest to astrobiology in-and-of themselves since they represent some of the main carriers of the biogenic elements C, H, O, and N. In addition, these compounds are present in the dense interstellar clouds in which new stars and planetary systems are formed and may play a large role in the delivery of volatiles and organics to the surfaces of new planets. However, these molecules are all far simpler than the more complex organic compounds found in living systems.

Green Synthetic Alternatives to Organic Compounds and Nanomaterials-May 2008

EPA Science Inventory

A brief account of reactions involving microwave (MW) exposure of neat reactants or catalyzed by mineral support surfaces, such as alumina, silica, clay, or their ‘doped’ versions, for the rapid one-pot assembly of heterocyclic compounds from in situ generated reactive intermedia...

Multitopic ligand directed assembly of low-dimensional metal-chalcogenide organic frameworks.

PubMed

Liu, Yi; Ye, Kaiqi; Wang, Yue; Zhang, Qichun; Bu, Xianhui; Feng, Pingyun

2017-01-31

Despite tremendous progress in metal-organic frameworks, only limited success has been achieved with metal-chalcogenide organic frameworks. Metal-chalcogenide organic frameworks are desirable because they offer a promising route towards tunable semiconducting porous frameworks. Here, four novel semiconducting chalcogenide-organic hybrid compounds have been synthesized through a solvothermal method. Multitopic organic molecules, i.e., 1,2-di-(4-pyridyl)ethylene (L 1 ), 1,3,5-tris(4-pyridyl-trans-ethenyl)benzene (L 2 ) and tetrakis(4-pyridyloxymethylene)methane (L 3 ), have been used as linkers to assemble Zn(SAr) 2 or Zn 2 (SAr) 4 units to generate different patterns of spatial organizations. Single-crystal structural analyses indicate that compounds NTU-2, NTU-3 and NTU-4 possess two-dimensional layer structures, while compound NTU-1 adopts a one-dimensional coordination framework (NTU-n, where n is the number related to a specific structure). The diffuse-reflectance spectra demonstrate that these four compounds possess indirect bandgaps and their tunable bandgaps are correlated with their compositions and crystal structures.

The statistical model of origin and evolution planets of Solar system and planetary satellities

NASA Astrophysics Data System (ADS)

Krot, A.

There are the theories for exploring Solar system formation in accord Titius-Bode's low: electromagnetic theories (Birkeland (1912), Alfven (1942)), gravitational theories (Schmidt (1944), Woolfson (1964), Safronov (1969), Dole (1970)), nebular theories (Weizsaecker (1943), Kuiper (1949), Nakano (1970)) [1]-[3]. In spite of great number of work aimed to exploring formation of the Solar system, however, the mentioned theories were not able to explain all phenomena. In this connection the statistical theory for a cosmological body forming (so-called the spheroidal body model) has been proposed in [4]-[11]. Within the framework of this theory, bodies have fuzzy outlines and are represented by means of spheroidal forms. In the work [6], which is a continuation of the papers [4], [5], it has been investigated a slowly evolving in time process of a gravitational compression of a spheroidal body close to an unstable equilibrium state. In the papers [7],[8]the equation of motion of particles inside the weakly gravitating spheroidal body modeled by means of an ideal liquid has been obtained. Using Schwarzschild's and Kerr's metrics a consistency of the proposed statistical model with the general relativity has been shown in [12]. The proposed theory proceeds from the conception for forming a spheroidal body as a protoplanet from planetary nebula; it permits to derive the form of distribution functions for an immovable and rotating spheroidal body [4]-[6],[10]-[13] as well as their density masses (gravitational potentials and strengths) and also to find the distribution function of specific angular momentum of the rotating uniformly spheroidal body [13],[14]. Using the specific angular momentum distribution function this work considers a gas- dust protoplanetary cloud as a rotating and gravitating spheroidal body. Because the specific angular momenta are averaged during conglomeration process the specific angular momenta for a planets of Solar system is found. As a result a new low for Solar system planetary distances is derived (it generalizes the well-known Schmidt low). The new low gives a very good estimation of real planetary distances in Solar system (the relative error of estimation is 0%; absolute error of estimation is 0,5% besides its maximal value is equal to 5% for Earth and Pluto). This low has been applied also to estimation of Jupiter's satellities distances in this work. References: [1] M.M.Nieto, The Tutius-Bode low of planetary distances: its his-tory and theory. Pergamon: Oxford, New York et., 1972. [2] V.S. Safronov, Evolution of Protoplanetary cloud and the formation of the Earth and planets. 1969, Moscow, Nauka, (in Russian); NASA Tech. Transl. F-677, Washington, D.C. 1972. [3] A.V. Vityazev, G.V. Pechrnikova and V.S.Safronov, The Terrestrial planets: origin and early evolution. 1990. Moscow, Nauka (in Russian) [4] A.M.Krot, Achievement in Modern Radioelectronics (Special issue "Cosmic Radiophysics", Moscow), no.8, pp.66-81, 1996 (in Russian). [5] A.M.Krot, Proc. SPIE's 13th Annual Intern.Symp. "AeroSense", vol.3710, pp.1248-1259, Orlando, Florida, USA, April 5-9, 1999. [6] A.M.Krot, Proc. SPIE's 14th Annual Intern.Symp. "AeroSense", vol.4038, pp.1318-1329, Orlando, Florida, USA, April 24-28, 2000. [7] A.M.Krot, Proc. SPIE's 15th Annual Intern. Symposium "AeroSense", vol.4394, pp.1271-1282, Orlando, Florida, USA, April 16-20, 2001. [8] A.M.Krot, Proc. 53rd Intern. Astronautical Congress: The World Space Congress-2002, Houston, Texas, USA, October 10-19, 2002, Preprint IAC-02-J.P.01. - 11 p. [9] A.M.Krot, Proc. 34th Scientific Assembly of the Committee on Space Research (COSPAR)- The 2nd World Space Congress (WSC- 2002), October 10-19, 2002,Houston, Texas, USA. [10] A.M.Krot, Proc. of EGS- AGU-EUG Joint Assembly, Nice, France, April 6-11, 2003, Geophysical Research Abstracts, vol.5, EAE03-À-05568, 2003. [11] A.M. Krot, Proc. of 54 Intern. Astronautical Congress (IAC), September 29-October 3, 2003, Bremen, Germany, Preprint IAC-03-J.1.08. -11p. [12] A.M.Krot , Proc. of 35th COSPAR Scientific Assembly, Paris, France, July 18-25, 2004, Abstract-Nr. COSPAR 04-A-00162. [13] A.Krot, Proc. EGU- 2nd General Assembly, Vienna, Austria, April 24-29, 2005, Geophysical Research Abstracts, vol.7, EGU05-A-04550, 2005; SRef-ID: 1607-7962/gra/. [14] A.Krot Proc. EGU- General Assembly, Vienna, Austria, April 02- 07, 2006, Geophysical Research Abstracts, vol.8, EGU06-A-00216, 2006; SRef-ID: 1607-7962/gra/. 2

Friction welded nonconsumable electrode assembly and use thereof for electrolytic production of metals and silicon

DOEpatents

Byrne, Stephen C.; Ray, Siba P.; Rapp, Robert A.

1984-01-01

A nonconsumable electrode assembly suitable for use in the production of metal by electrolytic reduction of a metal compound dissolved in a molten salt, the assembly comprising a metal conductor and a ceramic electrode body connected by a friction weld between a portion of the body having a level of free metal or metal alloy sufficient to effect such a friction weld and a portion of the metal conductor.

Accurate Treatment of Collisions and Water-Delivery in Models of Terrestrial Planet Formation

NASA Astrophysics Data System (ADS)

Haghighipour, Nader; Maindl, Thomas; Schaefer, Christoph

2017-10-01

It is widely accepted that collisions among solid bodies, ignited by their interactions with planetary embryos is the key process in the formation of terrestrial planets and transport of volatiles and chemical compounds to their accretion zones. Unfortunately, due to computational complexities, these collisions are often treated in a rudimentary way. Impacts are considered to be perfectly inelastic and volatiles are considered to be fully transferred from one object to the other. This perfect-merging assumption has profound effects on the mass and composition of final planetary bodies as it grossly overestimates the masses of these objects and the amounts of volatiles and chemical elements transferred to them. It also entirely neglects collisional-loss of volatiles (e.g., water) and draws an unrealistic connection between these properties and the chemical structure of the protoplanetary disk (i.e., the location of their original carriers). We have developed a new and comprehensive methodology to simulate growth of embryos to planetary bodies where we use a combination of SPH and N-body codes to accurately model collisions as well as the transport/transfer of chemical compounds. Our methodology accounts for the loss of volatiles (e.g., ice sublimation) during the orbital evolution of their careers and accurately tracks their transfer from one body to another. Results of our simulations show that traditional N-body modeling of terrestrial planet formation overestimates the amount of the mass and water contents of the final planets by over 60% implying that not only the amount of water they suggest is far from being realistic, small planets such as Mars can also form in these simulations when collisions are treated properly. We will present details of our methodology and discuss its implications for terrestrial planet formation and water delivery to Earth.

Light-triggered self-assembly of triarylamine-based nanospheres

NASA Astrophysics Data System (ADS)

Moulin, Emilie; Niess, Frédéric; Fuks, Gad; Jouault, Nicolas; Buhler, Eric; Giuseppone, Nicolas

2012-10-01

Tailored triarylamine units modified with terpyridine ligands were coordinated to Zn2+ ions and characterized as discrete dimeric entities. Interestingly, when these complexes were subsequently irradiated with simple visible light in chloroform, they readily self-assembled into monodisperse spheres with a mean diameter of 160 nm.Tailored triarylamine units modified with terpyridine ligands were coordinated to Zn2+ ions and characterized as discrete dimeric entities. Interestingly, when these complexes were subsequently irradiated with simple visible light in chloroform, they readily self-assembled into monodisperse spheres with a mean diameter of 160 nm. Electronic supplementary information (ESI) available: Synthetic procedures and products' characterization (2-4 and 6-9). 1H NMR titration of compound 6 by Zn(OTf)2 to form complex 7. Kinetic measurements by UV-Vis-NIR spectroscopy. Transmission electron microscopy imaging for complexes 8 and 9. UV-Vis-NIR for an Fe2+ analogue of complex 7. Dynamic light scattering and time autocorrelation function for self-assembly of complexes 7-9. Copies of 1H and 13C NMR spectra for compounds 2-4 and 6. See DOI: 10.1039/c2nr32168h

Tunable Gas Sensing Gels by Cooperative Assembly

PubMed Central

Hussain, Abid; Semeano, Ana T. S.; Palma, Susana I. C. J.; Pina, Ana S.; Almeida, José; Medrado, Bárbara F.; Pádua, Ana C. C. S.; Carvalho, Ana L.; Dionísio, Madalena; Li, Rosamaria W. C.; Gamboa, Hugo; Ulijn, Rein V.; Gruber, Jonas; Roque, Ana C. A.

2017-01-01

The cooperative assembly of biopolymers and small molecules can yield functional materials with precisely tunable properties. Here, the fabrication, characterization, and use of multicomponent hybrid gels as selective gas sensors are reported. The gels are composed of liquid crystal droplets self-assembled in the presence of ionic liquids, which further coassemble with biopolymers to form stable matrices. Each individual component can be varied and acts cooperatively to tune gels’ structure and function. The unique molecular environment in hybrid gels is explored for supramolecular recognition of volatile compounds. Gels with distinct compositions are used as optical and electrical gas sensors, yielding a combinatorial response conceptually mimicking olfactory biological systems, and tested to distinguish volatile organic compounds and to quantify ethanol in automotive fuel. The gel response is rapid, reversible, and reproducible. These robust, versatile, modular, pliant electro-optical soft materials possess new possibilities in sensing triggered by chemical and physical stimuli. PMID:28747856

Fabrication of MTN-type zeolite by self-assembling of supramolecular compound

NASA Astrophysics Data System (ADS)

Huang, Aisheng; Caro, Jürgen

2009-10-01

MTN-type (Zeolite Socony Mobil Thirty-Nine) zeolite was prepared at 473 K by a novel method through self-assembling of a supramolecular compound called 2,4,6-tris (4-pyridyl) triazine (TPT) in DMF (N,N-dimethylformamide). The effects of fluoride, DMF and germanium on the synthesis of MTN-type zeolite were investigated. The crystallization was facilitated by adding fluoride to the synthesis solution, resulting in the formation of highly crystalline MTN samples, while some amorphous phase was observed in fluoride-free batches. DMF was required to obtain a highly crystalline MTN sample, since TPT dissolves easier in DMF than in water, thus facilitating the self-assembling of TPT into a 3D network to structure the MTN framework. The MTN structure could be synthesized at low germanium content (Ge/Si≤0.18), while AST (AlPO 4-sixteen) as a foreign phase is formed at high germanium substitution (Ge/Si≥0.5).

Self-assembling of dihydroxypropyl 5,6-dihydrothymine derivatives

NASA Astrophysics Data System (ADS)

Cetina, Mario; Makarević, Janja; Nura-Lama, Afërdita

2010-09-01

( R, S)-1-(2',3'-Dibenzoyloxypropyl)-5,6-dihydrothymine ( 2) was synthesized from ( R, S)-1-(2',3'-dihydroxypropyl)-5,6-dihydrothymine and its structure has been analyzed by X-ray diffraction, NMR and FTIR spectroscopic methods. The molecular structure and supramolecular assembling of 2 is compared with the structure of its dimesyloxypropyl analogue ( 1). Compound 1 crystallizes as cocrystal of two diastereoisomers, while 2 crystallizes as a racemic mixture. Main hydrogen-bonded motif in both compounds is dimer formed by pair of N sbnd H···O( dbnd C) hydrogen bonds, which are further linked by C sbnd H···O hydrogen bonds. Phenyl rings of dibenzoyl-dihydropyrimidine moieties of 2 participate also in supramolecular aggregation via three C sbnd H···π interactions. Hydrogen bonding as driving force of 2 self-assembly was proving by the NMR and FTIR spectroscopy.

A virus-based biocatalyst

NASA Astrophysics Data System (ADS)

Carette, Noëlle; Engelkamp, Hans; Akpa, Eric; Pierre, Sebastien J.; Cameron, Neil R.; Christianen, Peter C. M.; Maan, Jan C.; Thies, Jens C.; Weberskirch, Ralf; Rowan, Alan E.; Nolte, Roeland J. M.; Michon, Thierry; van Hest, Jan C. M.

2007-04-01

Virus particles are probably the most precisely defined nanometre-sized objects that can be formed by protein self-assembly. Although their natural function is the storage and transport of genetic material, they have more recently been applied as scaffolds for mineralization and as containers for the encapsulation of inorganic compounds. The reproductive power of viruses has been used to develop versatile analytical methods, such as phage display, for the selection and identification of (bio)active compounds. To date, the combined use of self-assembly and reproduction has not been used for the construction of catalytic systems. Here we describe a self-assembled system based on a plant virus that has its coat protein genetically modified to provide it with a lipase enzyme. Using single-object and bulk catalytic studies, we prove that the virus-anchored lipase molecules are catalytically active. This anchored biocatalyst, unlike man-made supported catalysts, has the capability to reproduce itself in vivo, generating many independent catalytically active copies.

Large-area ordered Ge-Si compound quantum dot molecules on dot-patterned Si (001) substrates

NASA Astrophysics Data System (ADS)

Lei, Hui; Zhou, Tong; Wang, Shuguang; Fan, Yongliang; Zhong, Zhenyang

2014-08-01

We report on the formation of large-area ordered Ge-Si compound quantum dot molecules (CQDMs) in a combination of nanosphere lithography and self-assembly. Truncated-pyramid-like Si dots with {11n} facets are readily formed, which are spatially ordered in a large area with controlled period and size. Each Si dot induces four self-assembled Ge-rich dots at its base edges that can be fourfold symmetric along <110> directions. A model based on surface chemical potential accounts well for these phenomena. Our results disclose the critical effect of surface curvature on the diffusion and the aggregation of Ge adatoms and shed new light on the unique features and the inherent mechanism of self-assembled QDs on patterned substrates. Such a configuration of one Si QD surrounded by fourfold symmetric Ge-rich QDs can be seen as a CQDM with unique features, which will have potential applications in novel devices.

New insights about antibiotic production by Pseudomonas aeruginosa: a gene expression analysis

NASA Astrophysics Data System (ADS)

Gionco, Bárbara; Tavares, Eliandro R.; de Oliveira, Admilton G.; Yamada-Ogatta, Sueli F.; do Carmo, Anderson O.; Pereira, Ulisses de Pádua; Chideroli, Roberta T.; Simionato, Ane S.; Navarro, Miguel O. P.; Chryssafidis, Andreas L.; Andrade, Galdino

2017-09-01

The bacterial resistance for antibiotics is one of the most important problems in public health and only a small number of new products are in development. Antagonistic microorganisms from soil are a promising source of new candidate molecules. Products of secondary metabolism confer adaptive advantages for their producer, in the competition for nutrients in the microbial community. The biosynthesis process of compounds with antibiotic activity is the key to optimize their production and the transcriptomic study of microorganisms is of great benefit for the discovery of these metabolic pathways. Pseudomonas aeruginosa LV strain growing in the presence of copper chloride produces a bioactive organometallic compound, which has a potent antimicrobial activity against various microorganisms. The objective of this study was to verify overexpressed genes and evaluate their relation to the organometallic biosynthesis in this microorganism. P. aeruginosa LV strain was cultured in presence and absence of copper chloride. Two methods were used for transcriptomic analysis, genome reference-guided assembly and de novo assembly. The genome referenced analysis identified nine upregulated genes when bacteria were exposed to copper chloride, while the De Novo Assembly identified twelve upregulated genes. Nineteen genes can be related to an increased microbial metabolism for the extrusion process of exceeding intracellular copper. Two important genes are related to the biosynthesis of phenazine and tetrapyrroles compounds, which can be involved in the bioremediation of intracellular copper and biosynthesis of the organometallic compound. Additional studies are being carried out to further prove the function of the described genes and relate them to the biosynthetic pathway of the organometallic compound.

Origin of the Universe: From the First Stars to Planets with JWST

NASA Technical Reports Server (NTRS)

Clampin, Mark

2008-01-01

The James Webb Space Telescope (JWST) is a large aperture (6.5 meter), cryogenic space telescope with a suite of near and mid-infrared instruments. JWST's primary science goal is to detect and characterize the first galaxies. It will also study the assembly of galaxies, star formation, protoplanetary systems, and the formation of evolution of planetary systems. We will review the motivations for JWST's science goals in the context of recent Hubble Space Telescope, and Spitzer Space Telescope observations and review the status of the JWST Observatory.

Design of a novel, one-sided, pedal-activated wheelchair.

PubMed

Lin, T-Y; Hsiao, K-H; Yao, H-W

2011-07-01

The present paper proposes the design of a novel, one-sided, pedal-activated wheelchair for patients with hemiplegia or hemiparesis. The design comprises a planetary hub transmission, which is embedded in the hub of the wheelchair, with drive, neutral, and reverse modes. The paper first discusses the structural characteristics and motion transmission of the wheelchair, and then presents the motion design of the hub transmission, followed by assembly and testing of the prototype. The results confirm that the proposed wheelchair and hub transmission can meet users' demands, thus improving comfort and independence.

Capabilities of the James Webb Space Telescope for Exoplanet Science

NASA Technical Reports Server (NTRS)

Clampin, Mark

2009-01-01

The James Webb Space Telescope (JWST) is a large aperture (6.5 meter), cryogenic space telescope with a suite of near and mid-infrared instruments covering the wavelength range of 0.6 m to 28 m. JWST s primary science goal is to detect and characterize the first galaxies. It will also study the assembly of galaxies, star formation, and the formation of evolution of planetary systems. We also review the expected scientific performance of the observatory for observations of exosolar planets by means of transit photometry and spectroscopy, and direct coronagraphic imaging.

Design of a fast Mars space transfer system

NASA Astrophysics Data System (ADS)

Woo, Henry H.; Glass, James F.; Roy, Claude

1992-02-01

Architecture strategies and concepts for manned missions to Mars are being developed by NASA and industry. This paper addresses the key Mars transfer vehicle (MTV) design requirements which include surface payload mass, MTV mass, propulsion system characteristics, launch vehicle capability, in-space operations, abort considerations, crew exposure to interplanetary environments, and crew reconditioning for planetary entry. Different mission strategies are presented along with their implications. A representative artificial-g MTV using nuclear thermal propulsion is defined to show concepts which minimize extravehicular activity operations for in-space assembly, inspection, and maintenance.

Terrestrial applications of NASA space telerobotics technologies

NASA Technical Reports Server (NTRS)

Lavery, Dave

1994-01-01

In 1985 the National Aeronautics and Space Administration (NASA) instituted a research program in telerobotics to develop and provide the technology for applications of telerobotics to the United States space program. The activities of the program are intended to most effectively utilize limited astronaut time by facilitating tasks such as inspection, assembly, repair, and servicing, as well as providing extended capability for remotely conducting planetary surface operations. As the program matured, it also developed a strong heritage of working with government and industry to directly transfer the developed technology into industrial applications.

Services provided in support of the planetary quarantine requirements of the National Aeronautics and Space Administration

NASA Technical Reports Server (NTRS)

Favero, M. S.

1972-01-01

Heat studies with the highly resistant bacterial spore isolated from Cape Kennedy soil were continued, and the D130C was determined. The interior surfaces of the command module of the Apollo 17 spacecraft were studied for microbial contamination during assembly and testing. The thermal resistance of naturally occurring airborne bacterial spores was determined, using the heating times of 2, 4, 6, and 8 hr. at 125 C. The evaluation of a terminal sterilization process for unmanned lander spacecraft is also continuing.

Helical self-organization and hierarchical self-assembly of an oligoheterocyclic pyridine-pyridazine strand into extended supramolecular fibers.

PubMed

Cuccia, Louis A; Ruiz, Eliseo; Lehn, Jean-Marie; Homo, Jean-Claude; Schmutz, Marc

2002-08-02

The synthesis and characterization of an alternating pyridine-pyridazine strand comprising thirteen heterocycles are described. Spontaneous folding into a helical secondary structure is based on a general molecular self-organization process enforced by the conformational information encoded within the primary structure of the molecular strand itself. Conformational control based on heterocyclic "helicity codons" illustrates a strategy for designing folding properties into synthetic oligomers (foldamers). Strong intermolecular interactions of the highly ordered lock-washer subunits of compound 3 results in hierarchical supramolecular self-assembly into protofibrils and fibrils. Compound 3 also forms mechanically stable two-dimensional Langmuir-Blodgett and cast thin films.

Thermal Barriers Developed for Solid Rocket Motor Nozzle Joints

NASA Technical Reports Server (NTRS)

Steinetz, Bruce M.; Dunlap, Patrick H., Jr.

2000-01-01

Space shuttle solid rocket motor case assembly joints are sealed with conventional O-ring seals that are shielded from 5500 F combustion gases by thick layers of insulation and by special joint-fill compounds that fill assembly splitlines in the insulation. On a number of occasions, NASA has observed hot gas penetration through defects in the joint-fill compound of several of the rocket nozzle assembly joints. In the current nozzle-to-case joint, NASA has observed penetration of hot combustion gases through the joint-fill compound to the inboard wiper O-ring in one out of seven motors. Although this condition does not threaten motor safety, evidence of hot gas penetration to the wiper O-ring results in extensive reviews before resuming flight. The solid rocket motor manufacturer (Thiokol) approached the NASA Glenn Research Center at Lewis Field about the possibility of applying Glenn's braided fiber preform seal as a thermal barrier to protect the O-ring seals. Glenn and Thiokol are working to improve the nozzle-to-case joint design by implementing a more reliable J-leg design and by using a braided carbon fiber thermal barrier that would resist any hot gases that the J-leg does not block.

Inhibition of HIV-1 Maturation via Small-Molecule Targeting of the Amino-Terminal Domain in the Viral Capsid Protein.

PubMed

Wang, Weifeng; Zhou, Jing; Halambage, Upul D; Jurado, Kellie A; Jamin, Augusta V; Wang, Yujie; Engelman, Alan N; Aiken, Christopher

2017-05-01

The human immunodeficiency virus type 1 (HIV-1) capsid protein is an attractive therapeutic target, owing to its multifunctionality in virus replication and the high fitness cost of amino acid substitutions in capsids to HIV-1 infectivity. To date, small-molecule inhibitors have been identified that inhibit HIV-1 capsid assembly and/or impair its function in target cells. Here, we describe the mechanism of action of the previously reported capsid-targeting HIV-1 inhibitor, Boehringer-Ingelheim compound 1 (C1). We show that C1 acts during HIV-1 maturation to prevent assembly of a mature viral capsid. However, unlike the maturation inhibitor bevirimat, C1 did not significantly affect the kinetics or fidelity of Gag processing. HIV-1 particles produced in the presence of C1 contained unstable capsids that lacked associated electron density and exhibited impairments in early postentry stages of infection, most notably reverse transcription. C1 inhibited assembly of recombinant HIV-1 CA in vitro and induced aberrant cross-links in mutant HIV-1 particles capable of spontaneous intersubunit disulfide bonds at the interhexamer interface in the capsid lattice. Resistance to C1 was conferred by a single amino acid substitution within the compound-binding site in the N-terminal domain of the CA protein. Our results demonstrate that the binding site for C1 represents a new pharmacological vulnerability in the capsid assembly stage of the HIV-1 life cycle. IMPORTANCE The HIV-1 capsid protein is an attractive but unexploited target for clinical drug development. Prior studies have identified HIV-1 capsid-targeting compounds that display different mechanisms of action, which in part reflects the requirement for capsid function at both the efferent and afferent phases of viral replication. Here, we show that one such compound, compound 1, interferes with assembly of the conical viral capsid during virion maturation and results in perturbations at a specific protein-protein interface in the capsid lattice. We also identify and characterize a mutation in the capsid protein that confers resistance to the inhibitor. This study reveals a novel mechanism by which a capsid-targeting small molecule can inhibit HIV-1 replication. Copyright © 2017 American Society for Microbiology.

Features of Modularly Assembled Compounds That Impart Bioactivity Against an RNA Target

PubMed Central

Rzuczek, Suzanne G.; Gao, Yu; Tang, Zhen-Zhi; Thornton, Charles A.; Kodadek, Thomas; Disney, Matthew D.

2013-01-01

Transcriptomes provide a myriad of potential RNAs that could be the targets of therapeutics or chemical genetic probes of function. Cell permeable small molecules, however, generally do not exploit these targets, owing to the difficulty in the design of high affinity, specific small molecules targeting RNA. As part of a general program to study RNA function using small molecules, we designed bioactive, modularly assembled small molecules that target the non-coding expanded RNA repeat that causes myotonic dystrophy type 1 (DM1), r(CUG)exp. Herein, we present a rigorous study to elucidate features in modularly assembled compounds that afford bioactivity. Different modular assembly scaffolds were investigated including polyamines, α-peptides, β-peptides, and peptide tertiary amides (PTAs). Based on activity as assessed by improvement of DM1-associated defects, stability against proteases, cellular permeability, and toxicity, we discovered that constrained backbones, namely PTAs, are optimal. Notably, we determined that r(CUG)exp is the target of the optimal PTA in cellular models and that the optimal PTA improves DM1-associated defects in a mouse model. Biophysical analyses were employed to investigate potential sources of bioactivity. These investigations show that modularly assembled compounds have increased residence times on their targets and faster on rates than the RNA-binding modules from which they were derived and faster on rates than the protein that binds r(CUG)exp, the inactivation of which gives rise to DM1-associated defects. These studies provide information about features of small molecules that are programmable for targeting RNA, allowing for the facile optimization of therapeutics or chemical probes against other cellular RNA targets. PMID:24032410

Features of modularly assembled compounds that impart bioactivity against an RNA target.

PubMed

Rzuczek, Suzanne G; Gao, Yu; Tang, Zhen-Zhi; Thornton, Charles A; Kodadek, Thomas; Disney, Matthew D

2013-10-18

Transcriptomes provide a myriad of potential RNAs that could be the targets of therapeutics or chemical genetic probes of function. Cell-permeable small molecules, however, generally do not exploit these targets, owing to the difficulty in the design of high affinity, specific small molecules targeting RNA. As part of a general program to study RNA function using small molecules, we designed bioactive, modularly assembled small molecules that target the noncoding expanded RNA repeat that causes myotonic dystrophy type 1 (DM1), r(CUG)(exp). Herein, we present a rigorous study to elucidate features in modularly assembled compounds that afford bioactivity. Different modular assembly scaffolds were investigated, including polyamines, α-peptides, β-peptides, and peptide tertiary amides (PTAs). On the basis of activity as assessed by improvement of DM1-associated defects, stability against proteases, cellular permeability, and toxicity, we discovered that constrained backbones, namely, PTAs, are optimal. Notably, we determined that r(CUG)(exp) is the target of the optimal PTA in cellular models and that the optimal PTA improves DM1-associated defects in a mouse model. Biophysical analyses were employed to investigate potential sources of bioactivity. These investigations show that modularly assembled compounds have increased residence times on their targets and faster on rates than the RNA-binding modules from which they were derived. Moreover, they have faster on rates than the protein that binds r(CUG)(exp), the inactivation of which gives rise to DM1-associated defects. These studies provide information about features of small molecules that are programmable for targeting RNA, allowing for the facile optimization of therapeutics or chemical probes against other cellular RNA targets.

Synthesis of Polyheteroaromatic Compounds via Rhodium-Catalyzed Multiple C-H Bond Activation and Oxidative Annulation.

PubMed

Peng, Shiyong; Liu, Suna; Zhang, Sai; Cao, Shengyu; Sun, Jiangtao

2015-10-16

Polyheteroaromatic compounds are potential optoelectronic conjugated materials due to their electro- and photochemical properties. Transition-metal-catalyzed multiple C-H activation and sequential oxidative annulation allows rapidly assembling of those compounds from readily available starting materials. A rhodium-catalyzed cascade oxidative annulation of β-enamino esters or 4-aminocoumarins with internal alkynes is described to access those compounds, featuring multiple C-H/N-H bond cleavages and sequential C-C/C-N bond formations in one pot.

Optimization of sound absorbing performance for gradient multi-layer-assembled sintered fibrous absorbers

NASA Astrophysics Data System (ADS)

Zhang, Bo; Zhang, Weiyong; Zhu, Jian

2012-04-01

The transfer matrix method, based on plane wave theory, of multi-layer equivalent fluid is employed to evaluate the sound absorbing properties of two-layer-assembled and three-layer-assembled sintered fibrous sheets (generally regarded as a kind of compound absorber or structures). Two objective functions which are more suitable for the optimization of sound absorption properties of multi-layer absorbers within the wider frequency ranges are developed and the optimized results of using two objective functions are also compared with each other. It is found that using the two objective functions, especially the second one, may be more helpful to exert the sound absorbing properties of absorbers at lower frequencies to the best of their abilities. Then the calculation and optimization of sound absorption properties of multi-layer-assembled structures are performed by developing a simulated annealing genetic arithmetic program and using above-mentioned objective functions. Finally, based on the optimization in this work the thoughts of the gradient design over the acoustic parameters- the porosity, the tortuosity, the viscous and thermal characteristic lengths and the thickness of each samples- of porous metals are put forth and thereby some useful design criteria upon the acoustic parameters of each layer of porous fibrous metals are given while applying the multi-layer-assembled compound absorbers in noise control engineering.

Nanoscale Platelet Formation by Monounsaturated and Saturated Sophorolipids under Basic pH Conditions.

PubMed

Cuvier, Anne-Sophie; Babonneau, Florence; Berton, Jan; Stevens, Christian V; Fadda, Giulia C; Péhau-Arnaudet, Gérard; Le Griel, Patrick; Prévost, Sylvain; Perez, Javier; Baccile, Niki

2015-12-21

The self-assembly behavior of the yeast-derived bolaamphiphile sophorolipid (SL) is generally studied under acidic/neutral pH conditions, at which micellar and fibrillar aggregates are commonly found, according to the (un)saturation of the aliphatic chain: the cis form, which corresponds to the oleic acid form of SL, spontaneously forms micelles, whereas the saturated form, which corresponds to the stearic acid form of SL, preferentially forms chiral fibers. By using small-angle light and X-ray scattering (SLS, SAXS) combined with high-sensitivity transmission electron microscopy imaging under cryogenic conditions (cryo-TEM), the nature of the self-assembled structures formed by these two compounds above pH 10, which is the pH at which they are negatively charged due to the presence of a carboxylate group, has been explored. Under these conditions, these compounds self-assemble into nanoscale platelets, despite the different molecular structures. This work shows that the electrostatic repulsion forces generated by COO(-) mainly drive the self-assembly process at basic pH, in contrast with that found at pH below neutrality, at which self-assembly is driven by van der Waals forces and hydrogen bonding, and thus, is in agreement with previous findings on carbohydrate-based gemini surfactants. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Natural Product N-Palmitoyl-l-leucine Selectively Inhibits Late Assembly of Human Spliceosomes*

PubMed Central

Effenberger, Kerstin A.; James, Robert C.; Urabe, Veronica K.; Dickey, Bailey J.; Linington, Roger G.; Jurica, Melissa S.

2015-01-01

The spliceosome is a dynamic complex of five structural RNAs and dozens of proteins, which assemble together to remove introns from nascent eukaryotic gene transcripts in a process called splicing. Small molecules that target different components of the spliceosome represent valuable research tools to investigate this complicated macromolecular machine. However, the current collection of spliceosome inhibitors is very limited. To expand the toolkit we used a high-throughput in vitro splicing assay to screen a collection of pre-fractions of natural compounds derived from marine bacteria for splicing inhibition. Further fractionation of initial hits generated individual peaks of splicing inhibitors that interfere with different stages of spliceosome assembly. With additional characterization of individual peaks, we identified N-palmitoyl-l-leucine as a new splicing inhibitor that blocks a late stage of spliceosome assembly. Structure-activity relationship analysis of the compound revealed that length of carbon chain is important for activity in splicing, as well as for effects on the cytological profile of cells in culture. Together these results demonstrate that our combination of in vitro splicing analysis with complex natural product libraries is a powerful strategy for identifying new small molecule tools with which to probe different aspects of spliceosome assembly and function. PMID:26408199

Antarctic Planetary Testbed (APT): A facility in the Antarctic for research, planning and simulation of manned planetary missions and to provide a testbed for technological development

NASA Technical Reports Server (NTRS)

Ahmadi, Mashid; Bottelli, Alejandro Horacio; Brave, Fernando Luis; Siddiqui, Muhammad Ali

1988-01-01

The notion of using Antarctica as a planetary analog is not new. Ever since the manned space program gained serious respect in the 1950's, futurists have envisioned manned exploration and ultimate colonization of the moon and other extraterrestrial bodies. In recent years, much attention has been focused on a permanently manned U.S. space station, a manned Lunar outpost and a manned mission to Mars and its vicinity. When such lofty goals are set, it is only prudent to research, plan and rehearse as many aspects of such a mission as possible. The concept of the Antarctic Planetary Testbed (APT) project is intended to be a facility that will provide a location to train and observe potential mission crews under conditions of isolation and severity, attempting to simulate an extraterrestrial environment. Antarctica has been considered as an analog by NASA for Lunar missions and has also been considered by many experts to be an excellent Mars analog. Antarctica contains areas where the environment and terrain are more similar to regions on the Moon and Mars than any other place on Earth. These features offer opportunities for simulations to determine performance capabilities of people and machines in harsh, isolated environments. The initial APT facility, conceived to be operational by the year 1991, will be constructed during the summer months by a crew of approximately twelve. Between six and eight of these people will remain through the winter. As in space, structures and equipment systems will be modular to facilitate efficient transport to the site, assembly, and evolutionary expansion. State of the art waste recovery/recycling systems are also emphasized due to their importance in space.

Effective Utilization of Resources and Infrastructure for a Spaceport Network Architecture

NASA Technical Reports Server (NTRS)

Gill, Tracy; Larson, Wiley; Mueller, Robert; Roberson, Luke

2012-01-01

Providing routine, affordable access to a variety of orbital and deep space destinations requires an intricate network of ground, planetary surface, and space-based spaceports like those on Earth (land and sea), in various Earth orbits, and on other extraterrestrial surfaces. Advancements in technology and international collaboration are critical to establish a spaceport network that satisfies the requirements for private and government research, exploration, and commercial objectives. Technologies, interfaces, assembly techniques, and protocols must be adapted to enable mission critical capabilities and interoperability throughout the spaceport network. The conceptual space mission architecture must address the full range of required spaceport services, from managing propellants for a variety of spacecraft to governance structure. In order to accomplish affordability and sustainability goals, the network architecture must consider deriving propellants from in situ planetary resources to the maximum extent possible. Water on the Moon and Mars, Mars' atmospheric CO2, and O2 extracted from lunar regolith are examples of in situ resources that could be used to generate propellants for various spacecraft, orbital stages and trajectories, and the commodities to support habitation and human operations at these destinations. The ability to use in-space fuel depots containing in situ derived propellants would drastically reduce the mass required to launch long-duration or deep space missions from Earth's gravity well. Advances in transformative technologies and common capabilities, interfaces, umbilicals, commodities, protocols, and agreements will facilitate a cost-effective, safe, reliable infrastructure for a versatile network of Earth- and extraterrestrial spaceports. Defining a common infrastructure on Earth, planetary surfaces, and in space, as well as deriving propellants from in situ planetary resources to construct in-space propellant depots to serve the spaceport network, will reduce exploration costs due to standardization of infrastructure commonality and reduction in number and types of interfaces and commodities.

Process for producing elements from a fused bath using a metal strap and ceramic electrode body nonconsumable electrode assembly

DOEpatents

Byrne, Stephen C.

1984-01-01

A nonconsumable electrode assembly suitable for use in the production of metal by electrolytic reduction of a metal compound dissolved in a molten salt, the assembly comprising a ceramic electrode body and a metal subassembly of a metal conductor rod and at least one metal strap affixed to an end of the rod with opposing portions extending radially outwardly from the rod axis and having the ends of the strap attached to the electrode body.

The Walkback Test: A Study to Evaluate Suit and Life Support System Performance Requirements for a 10 Kilometer Traverse in a Planetary Suit

NASA Technical Reports Server (NTRS)

Vos, Jessica R.; Gernhardt, Michael L.; Lee, Lesley

2007-01-01

As planetary suit and planetary life support systems develop, specific design inputs for each system relate to a presently unanswered question concerning operational concepts: What distance can be considered a safe walking distance for a suited EVA crew member exploring the surface of the Moon to "walk-back" to the habitat in the event of a rover breakdown, taking into consideration the planned EVA tasks as well as the possible traverse back to the habitat? It has been assumed, based on Apollo program experience, that 10 kilometers (6.2 mi) will be the maximum EVA excursion distance from the lander or habitat to ensure the crew member s safe return to the habitat in the event of a rover failure. To investigate the feasibility of performing a suited 10 km Walkback, NASA-JSC assembled a multi-disciplinary team to design and implement the Lunar Walkback Test . The test was designed not only to determine the feasibility of a 10 km excursion, but also to collect human performance, biomedical, and biomechanical data relevant to optimizing space suit design and life support system sizing. These data will also be used to develop follow-on studies to understand interrelationships of such key parameters as suit mass, inertia, suit pressure, and center of gravity (CG), and the respective influences of each on human performance.

Evolving directions in NASA's planetary rover requirements and technology

NASA Astrophysics Data System (ADS)

Weisbin, C. R.; Montemerlo, Mel; Whittaker, W.

1993-10-01

This paper reviews the evolution of NASA's planning for planetary rovers (i.e. robotic vehicles which may be deployed on planetary bodies for exploration, science analysis, and construction) and some of the technology that has been developed to achieve the desired capabilities. The program is comprised of a variety of vehicle sizes and types in order to accommodate a range of potential user needs. This includes vehicles whose weight spans a few kilograms to several thousand kilograms; whose locomotion is implemented using wheels, tracks, and legs; and whose payloads vary from microinstruments to large scale assemblies for construction. We first describe robotic vehicles, and their associated control systems, developed by NASA in the late 1980's as part of a proposed Mars Rover Sample Return (MRSR) mission. Suggested goals at that time for such an MRSR mission included navigating for one to two years across hundreds of kilometers of Martian surface; traversing a diversity of rugged, unknown terrain; collecting and analyzing a variety of samples; and bringing back selected samples to the lander for return to Earth. Subsequently, we present the current plans (considerably more modest) which have evolved both from technological 'lessons learned' in the previous period, and modified aspirations of NASA missions. This paper describes some of the demonstrated capabilities of the developed machines and the technologies which made these capabilities possible.

A scheme for a high-power, low-cost transmitter for deep space applications

NASA Astrophysics Data System (ADS)

Scheffer, L. K.

2005-10-01

Applications such as planetary radars and spacecraft communications require transmitters with extremely high effective isotropic radiated power. Until now, this has been done by combining a high-power microwave source with a large reflective antenna. However, this arrangement has a number of disadvantages. It is costly, since the steerable reflector alone is quite expensive, and for spacecraft communications, the need to transmit hurts the receive performance. For planetary radars, the utilization is very low since the antenna must be shared with other applications such as radio astronomy or spacecraft communications. This paper describes a potential new way of building such transmitters with lower cost, greater versatility, higher reliability, and potentially higher power. The basic idea is a phased array with a very large number of low-power elements, built with mass production techniques that have been optimized for consumer markets. The antennas are built en mass on printed circuit boards and are driven by chips, built with consumer complementary metal-oxide-semiconductor technology, that adjust the phase of each element. Assembly and maintenance should be comparatively inexpensive since the boards need only be attached to large, flat, unmoving, ground-level infrastructure. Applications to planetary radar and spacecraft communications are examined. Although we would be unlikely to use such a facility in this way, an implication for Search for Extraterrestrial Intelligence (SETI) is that high-power beacons are easier to build than had been thought.

Evolving directions in NASA's planetary rover requirements and technology

NASA Technical Reports Server (NTRS)

Weisbin, C. R.; Montemerlo, Mel; Whittaker, W.

1993-01-01

This paper reviews the evolution of NASA's planning for planetary rovers (i.e. robotic vehicles which may be deployed on planetary bodies for exploration, science analysis, and construction) and some of the technology that has been developed to achieve the desired capabilities. The program is comprised of a variety of vehicle sizes and types in order to accommodate a range of potential user needs. This includes vehicles whose weight spans a few kilograms to several thousand kilograms; whose locomotion is implemented using wheels, tracks, and legs; and whose payloads vary from microinstruments to large scale assemblies for construction. We first describe robotic vehicles, and their associated control systems, developed by NASA in the late 1980's as part of a proposed Mars Rover Sample Return (MRSR) mission. Suggested goals at that time for such an MRSR mission included navigating for one to two years across hundreds of kilometers of Martian surface; traversing a diversity of rugged, unknown terrain; collecting and analyzing a variety of samples; and bringing back selected samples to the lander for return to Earth. Subsequently, we present the current plans (considerably more modest) which have evolved both from technological 'lessons learned' in the previous period, and modified aspirations of NASA missions. This paper describes some of the demonstrated capabilities of the developed machines and the technologies which made these capabilities possible.

Raman spectroscopy in astrobiology.

PubMed

Jorge Villar, Susana E; Edwards, Howell G M

2006-01-01

Raman spectroscopy is proposed as a valuable analytical technique for planetary exploration because it is sensitive to organic and inorganic compounds and able to unambiguously identify key spectral markers in a mixture of biological and geological components; furthermore, sample manipulation is not required and any size of sample can be studied without chemical or mechanical pretreatment. NASA and ESA are considering the adoption of miniaturised Raman spectrometers for inclusion in suites of analytical instrumentation to be placed on robotic landers on Mars in the near future to search for extinct or extant life signals. In this paper we review the advantages and limitations of Raman spectroscopy for the analysis of complex specimens with relevance to the detection of bio- and geomarkers in extremophilic organisms which are considered to be terrestrial analogues of possible extraterrestial life that could have developed on planetary surfaces.

Inhibition Of Call-Cell Binding By Kipid Assemblies

DOEpatents

Nagy, Jon O. , Bargatze, Robert F.

2003-12-16

This invention relates generally to the field of therapeutic compounds designed to interfere between the binding of ligands and their receptors on cell surface. More specifically, it provides products and methods for inhibiting cell migration and activation using lipid assemblies with surface recognition elements that are specific for the receptors involved in cell migration and activation.

Inhibition of cell-cell binding by lipid assemblies

DOEpatents

Nagy, Jon O.; Bargatze, Robert F.

2001-05-22

This invention relates generally to the field of therapeutic compounds designed to interfere between the binding of ligands and their receptors on cell surface. More specifically, it provides products and methods for inhibiting cell migration and activation using lipid assemblies with surface recognition elements that are specific for the receptors involved in cell migration and activation.

Self-assembly of silver(i)-based high-energy metal-organic frameworks (HE-MOFs) at ambient temperature and pressure: synthesis, structure and superior explosive performance.

PubMed

Shen, Cheng; Liu, Yang; Zhu, Zhong-Qin; Xu, Yuan-Gang; Lu, Ming

2017-07-04

Two new high-energy metal-organic frameworks (HE-MOFs), {Ag 2 (DNMAF)(H 2 O) 2 } n (1) and {Ag 2 (DNMAF)} n (2) were prepared using potassium 4,4'-bis(dinitromethyl)-3,3'-azofurazanate (K 2 DNMAF) in a self-assembly strategy. Compound 1 exhibits a 3D HE-MOF structure with coordinated water molecules. Compound 2 exhibits compact solvent-free 3D HE-MOFs. Both compounds show good thermostability (decomposition temperature (T d ) of 211 and 218 °C) and superior detonation velocities (D) of 9673 m s -1 and 10 242 m s -1 , detonation pressures (P) of 50.01 GPa and 58.30 GPa, and heat of detonation (Q) of 1.95 kcal g -1 and 2.19 kcal g -1 , respectively, which are even higher than those of RDX and HMX.

Molecular studies of Planetary Nebulae

NASA Astrophysics Data System (ADS)

Zhang, Yong

2017-10-01

Circumstellar envelopes (CEs) around evolved stars are an active site for the production of molecules. After evolving through the Asymptotic Giant Branch (AGB), proto-planetary nebula (PPN), to planetary nebula (PN) phases, CEs ultimately merge with the interstellar medium (ISM). The study of molecules in PNe, therefore, is essential to understanding the transition from stellar to interstellar materials. So far, over 20 molecular species have been discovered in PNe. The molecular composition of PNe is rather different from those of AGB and PPNe, suggesting that the molecules synthesized in PN progenitors have been heavily processed by strong ultraviolet radiation from the central star. Intriguingly, fullerenes and complex organic compounds having aromatic and aliphatic structures can be rapidly formed and largely survive during the PPN/PN evolution. The similar molecular compositions in PNe and diffuse clouds as well as the detection of C60 + in the ISM reinforce the view that the mass-loss from PNe can significantly enrich the ISM with molecular species, some of which may be responsible for the diffuse interstellar bands. In this contribution, I briefly summarize some recent observations of molecules in PNe, with emphasis on their implications on circumstellar chemistry.

Recent progress in exobiology and planetary biology

NASA Technical Reports Server (NTRS)

Jukes, T. H.

1981-01-01

Recent work in the fields of exobiology, the study of the possible characteristics of extraterrestrial life, and planetary biology, the study of life forms as a function of planetary conditions, is reviewed. Searches conducted for life on Mars by the Viking Landers and on Titan by Voyager 1 are considered, and the origin of life on earth is considered in relation to the question of the inorganic trace elements in living systems that are required for life. The question of the origin of terrestrial life from spores carried through the interstellar medium is examined, and the unlikelihood of the survival of such spores except within meteorites or dust particles is pointed out. Studies of organic molecules present in the interstellar medium are indicated as evidence that the conditions necessary for the formation of life can exist in various locations throughout the universe. Investigations of the molecular evolution of life on earth and of life under extreme conditions of heat, cold, drought and ultraviolet radiation, and of the organic compounds found in meteorites and comets are also discussed. The importance of a mechanism of heredity, such as terrestrial DNA, to the evolution of terrestrial and possible extraterrestrial life is pointed out.

The Adaptability of Life on Earth and the Diversity of Planetary Habitats.

PubMed

Schulze-Makuch, Dirk; Airo, Alessandro; Schirmack, Janosch

2017-01-01

The evolutionary adaptability of life to extreme environments is astounding given that all life on Earth is based on the same fundamental biochemistry. The range of some physicochemical parameters on Earth exceeds the ability of life to adapt, but stays within the limits of life for other parameters. Certain environmental conditions such as low water availability in hyperarid deserts on Earth seem to be close to the limit of biological activity. A much wider range of environmental parameters is observed on planetary bodies within our Solar System such as Mars or Titan, and presumably even larger outside of our Solar System. Here we review the adaptability of life as we know it, especially regarding temperature, pressure, and water activity. We use then this knowledge to outline the range of possible habitable environments for alien planets and moons and distinguish between a variety of planetary environment types. Some of these types are present in our Solar System, others are hypothetical. Our schematic categorization of alien habitats is limited to life as we know it, particularly regarding to the use of solvent (water) and energy source (light and chemical compounds).

The Adaptability of Life on Earth and the Diversity of Planetary Habitats

PubMed Central

Schulze-Makuch, Dirk; Airo, Alessandro; Schirmack, Janosch

2017-01-01

The evolutionary adaptability of life to extreme environments is astounding given that all life on Earth is based on the same fundamental biochemistry. The range of some physicochemical parameters on Earth exceeds the ability of life to adapt, but stays within the limits of life for other parameters. Certain environmental conditions such as low water availability in hyperarid deserts on Earth seem to be close to the limit of biological activity. A much wider range of environmental parameters is observed on planetary bodies within our Solar System such as Mars or Titan, and presumably even larger outside of our Solar System. Here we review the adaptability of life as we know it, especially regarding temperature, pressure, and water activity. We use then this knowledge to outline the range of possible habitable environments for alien planets and moons and distinguish between a variety of planetary environment types. Some of these types are present in our Solar System, others are hypothetical. Our schematic categorization of alien habitats is limited to life as we know it, particularly regarding to the use of solvent (water) and energy source (light and chemical compounds). PMID:29085352

Planetary protection issues and future Mars missions

NASA Technical Reports Server (NTRS)

Devincenzi, D. L.; Klein, H. P.; Bagby, J. R.

1991-01-01

A primary scientific theme for the Space Exploration Initiative (SEI) is the search for life, extant or extinct, on Mars. Because of this, concerns have arisen about Planetary Protection (PP), the prevention of biological cross-contamination between Earth and other planets during solar system exploration missions. A recent workshop assessed the necessity for, and impact of, PP requirements on the unmanned and human missions to Mars comprising the SEI. The following ground-rules were adopted: (1) Information needed for assessing PP issues must be obtained during the unmanned precursor mission phase prior to human landings. (2) Returned Mars samples will be considered biologically hazardous until proven otherwise. (3) Deposition of microbes on Mars and exposure of the crew to martian materials are inevitable when humans land. And (4) Human landings are unlikely until it is demonstrated that there is no harmful effect of martian materials on terrestrial life forms. These ground-rules dictated the development of a conservative PP strategy for precursor missions. Key features of the proposed strategy include: to prevent forward-contamination, all orbiters will follow Mars Observer PP procedures for assembly, trajectory, and lifetime. All landers will follow Viking PP procedures for assembly, microbial load reduction, and bio-shield. And, to prevent back-contamination, all sample return missions will have PP requirements which include fail-safe sample sealing, breaking contact chain with the martian surface, and containment and quarantine analysis in Earth-based laboratory. In addition to deliberating on scientific and technical issues, the workshop made several recommendations for dealing with forward and back-contamination concerns from non-scicntific perspectives.

TESTING IN SITU ASSEMBLY WITH THE KEPLER PLANET CANDIDATE SAMPLE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hansen, Brad M. S.; Murray, Norm, E-mail: hansen@astro.ucla.edu, E-mail: murray@cita.utoronto.ca

2013-09-20

We present a Monte Carlo model for the structure of low-mass (total mass <25 M{sub ⊕}) planetary systems that form by the in situ gravitational assembly of planetary embryos into final planets. Our model includes distributions of mass, eccentricity, inclination, and period spacing that are based on the simulation of a disk of 20 M{sub ⊕}, forming planets around a solar-mass star, and assuming a power-law surface density distribution that drops with distance a as ∝ a {sup –1.5}. The output of the Monte Carlo model is then subjected to the selection effects that mimic the observations of a transitingmore » planet search such as that performed by the Kepler satellite. The resulting comparison of the output to the properties of the observed sample yields an encouraging agreement in terms of the relative frequencies of multiple-planet systems and the distribution of the mutual inclinations when moderate tidal circularization is taken into account. The broad features of the period distribution and radius distribution can also be matched within this framework, although the model underpredicts the distribution of small period ratios. This likely indicates that some dissipation is still required in the formation process. The most striking deviation between the model and observations is in the ratio of single to multiple systems in that there are roughly 50% more single-planet candidates observed than are produced in any model population. This suggests that some systems must suffer additional attrition to reduce the number of planets or increase the range of inclinations.« less

Fourth Symposium on Chemical Evolution and the Origin and Evolution of Life

NASA Technical Reports Server (NTRS)

Wharton, Robert A., Jr. (Editor); Andersen, Dale T. (Editor); Bzik, Sara E. (Editor); Rummel, John D. (Editor)

1991-01-01

This symposium was held at the NASA Ames Research Center, Moffett Field, California, July 24-27, 1990. The NASA exobiology investigators reported their recent research findings. Scientific papers were presented in the following areas: cosmic evolution of biogenic compounds, prebiotic evolution (planetary and molecular), early evolution of life (biological and geochemical), evolution of advanced life, solar system exploration, and the Search for Extraterrestrial Intelligence (SETI).

Cytochemical studies of planetary microorganisms - Explorations in exobiology

NASA Technical Reports Server (NTRS)

Lederberg, J.

1972-01-01

Analytical methodology using gas chromatography and mass spectrography for improved physiological monitoring of astronauts is developed. Reported research covers the following topics: (1) Chlorination of DNA bases; (2) mass fragmentography; (3) mass spectrometry; (4) urine analysis for metabolic constituents; (5) analysis of natural products by mass spectrometry; (6) computer identification of unknown molecular compounds; (7) fluorescent sorter for cell separation; (8) Mariner Mars 1971 orbital photography; and (9) Viking Lander imagery.

Experimental and theoretical studies on the gas/solid/gas transformation cycle in extraterrestrial environments

NASA Astrophysics Data System (ADS)

Cottin, Hervé; Gazeau, Marie-Claire; Chaquin, Patrick; Raulin, François; Bénilan, Yves

2001-12-01

The ubiquity of molecular material in the universe, from hydrogen to complex organic matter, is the result of intermixed physicochemical processes that have occurred throughout history. In particular, the gas/solid/gas phase transformation cycle plays a key role in chemical evolution of organic matter from the interstellar medium to planetary systems. This paper focuses on two examples that are representative of the diversity of environments where such transformations occur in the Solar System: (1) the photolytic evolution from gaseous to solid material in methane containing planetary atmospheres and (2) the degradation of high molecular weight compounds into gas phase molecules in comets. We are currently developing two programs which couple experimental and theoretical studies. The aim of this research is to provide data necessary to build models in order to better understand (1) the photochemical evolution of Titan's atmosphere, through a laboratory program to determine quantitative spectroscopic data on long carbon chain molecules (polyynes) obtained in the SCOOP program (French acronym for Spectroscopy of Organic Compounds Oriented for Planetology), and (2) the extended sources in comets, through a laboratory program of quantitative studies of photochemical and thermal degradation processes on relevant polymers (e.g., Polyoxymethylene) by the SEMAPhOrE Cometaire program (French acronym for Experimental Simulation and Modeling Applied to Organic Chemistry in Cometary Environment).

Direct assembling methodologies for high-throughput bioscreening

PubMed Central

Rodríguez-Dévora, Jorge I.; Shi, Zhi-dong; Xu, Tao

2012-01-01

Over the last few decades, high-throughput (HT) bioscreening, a technique that allows rapid screening of biochemical compound libraries against biological targets, has been widely used in drug discovery, stem cell research, development of new biomaterials, and genomics research. To achieve these ambitions, scaffold-free (or direct) assembly of biological entities of interest has become critical. Appropriate assembling methodologies are required to build an efficient HT bioscreening platform. The development of contact and non-contact assembling systems as a practical solution has been driven by a variety of essential attributes of the bioscreening system, such as miniaturization, high throughput, and high precision. The present article reviews recent progress on these assembling technologies utilized for the construction of HT bioscreening platforms. PMID:22021162

Free-Standing Self-Assemblies of Gallium Nitride Nanoparticles: A Review

DOE PAGES

Lan, Yucheng; Li, Jianye; Wong-Ng, Winnie; ...

2016-08-23

Gallium nitride (GaN) is an III-V semiconductor with a direct band-gap of 3.4eV . GaN has important potentials in white light-emitting diodes, blue lasers, and field effect transistors because of its super thermal stability and excellent optical properties, playing main roles in future lighting to reduce energy cost and sensors to resist radiations. GaN nanomaterials inherit bulk properties of the compound while possess novel photoelectric properties of nanomaterials. The review focuses on self-assemblies of GaN nanoparticles without templates, growth mechanisms of self-assemblies, and potential applications of the assembled nanostructures on renewable energy.

In Situ Biological Contamination Studies of the Moon: Implications for Future Planetary Protection and Life Detection Missions

NASA Technical Reports Server (NTRS)

Glavin, Daniel P.; Dworkin, Jason P.; Lupisella, Mark; Kminek, Gerhard; Rummel, John D.

2010-01-01

NASA and ESA have outlined visions for solar system exploration that will include a series of lunar robotic precursor missions to prepare for, and support a human return to the Moon, and future human exploration of Mars and other destinations. One of the guiding principles for exploration is to pursue compelling scientific questions about the origin and evolution of life. The search for life on objects such as Mars will require that all spacecraft and instrumentation be sufficiently cleaned and sterilized prior to launch to ensure that the scientific integrity of extraterrestrial samples is not jeopardized by terrestrial organic contamination. Under the Committee on Space Research's (COSPAR's) current planetary protection policy for the Moon, no sterilization procedures are required for outbound lunar spacecraft, nor is there yet a planetary protection category for human missions. Future in situ investigations of a variety of locations on the Moon by highly sensitive instruments designed to search for biologically derived organic compounds would help assess the contamination of the Moon by lunar spacecraft. These studies could also provide valuable "ground truth" data for Mars sample return missions and help define planetary protection requirements for future Mars bound spacecraft carrying life detection experiments. In addition, studies of the impact of terrestrial contamination of the lunar surface by the Apollo astronauts could provide valuable data to help refine future Mars surface exploration plans for a human mission to Mars.

New Insights about Antibiotic Production by Pseudomonas aeruginosa: A Gene Expression Analysis

PubMed Central

Gionco, Bárbara; Tavares, Eliandro R.; de Oliveira, Admilton G.; Yamada-Ogatta, Sueli F.; do Carmo, Anderson O.; Pereira, Ulisses de Pádua; Chideroli, Roberta T.; Simionato, Ane S.; Navarro, Miguel O. P.; Chryssafidis, Andreas L.; Andrade, Galdino

2017-01-01

The bacterial resistance for antibiotics is one of the most important problems in public health and only a small number of new products are in development. Antagonistic microorganisms from soil are a promising source of new candidate molecules. Products of secondary metabolism confer adaptive advantages for their producer, in the competition for nutrients in the microbial community. The biosynthesis process of compounds with antibiotic activity is the key to optimize their production and the transcriptomic study of microorganisms is of great benefit for the discovery of these metabolic pathways. Pseudomonas aeruginosa LV strain growing in the presence of copper chloride produces a bioactive organometallic compound, which has a potent antimicrobial activity against various microorganisms. The objective of this study was to verify overexpressed genes and evaluate their relation to the organometallic biosynthesis in this microorganism. P. aeruginosa LV strain was cultured in presence and absence of copper chloride. Two methods were used for transcriptomic analysis, genome reference-guided assembly and de novo assembly. The genome referenced analysis identified nine upregulated genes when bacteria were exposed to copper chloride, while the De Novo Assembly identified 12 upregulated genes. Nineteen genes can be related to an increased microbial metabolism for the extrusion process of exceeding intracellular copper. Two important genes are related to the biosynthesis of phenazine and tetrapyrroles compounds, which can be involved in the bioremediation of intracellular copper and we suggesting that may involve in the biosynthesis of the organometallic compound. Additional studies are being carried out to further prove the function of the described genes and relate them to the biosynthetic pathway of the organometallic compound. PMID:28966922

Origins of the Lunar and Planetary Laboratory, University of Arizona

NASA Technical Reports Server (NTRS)

Cruikshank, Dale P.; Hartmann, W. K.

2014-01-01

The roots of the Lunar and Planetary Laboratory (LPL) extend deep into the rich fabric of G. P. Kuiper's view of the Earth as a planet and planetary systems as expected companions to most stars, as well as the post-war emergent technology of infrared detectors suitable for astronomy. These concepts and events began with Kuiper's theoretical work at Yerkes Observatory on the origin of the Solar System, his discovery of two planetary satellites and observational work with his near-infrared spectrometer on the then-new McDonald 82-inch telescope in the mid- to late-1940s. A grant for the production of a photographic atlas of the Moon in the mid-1950s enabled him to assemble the best existing images of the Moon and acquire new photographs. This brought E. A. Whitaker and D. W. G. Arthur to Yerkes. Others who joined in the lunar work were geologist Carl S. Huzzen and grad student E. P. Moore, as well as undergrad summer students A. B. Binder and D. P. Cruikshank (both in 1958). The Atlas was published in 1959, and work began on an orthographic lunar atlas. Kuiper's view of planetary science as an interdisciplinary enterprise encompassing astronomy, geology, and atmospheric physics inspired his vision of a research institution and an academic curriculum tuned to the combination of all the scientific disciplines embraced in a comprehensive study of the planets. Arrangements were made with the University of Arizona (UA) to establish LPL in affiliation with the widely recognized Inst. of Atmospheric Physics. Kuiper moved to the UA in late 1960, taking the lunar experts, graduate student T. C. Owen (planetary atmospheres), and associate B. M. Middlehurst along. G. van Biesbroeck also joined the migration to Tucson; Binder and Cruikshank followed along as new grad students. Astronomy grad student W. K. Hartmann came into the academic program at UA and the research group at LPL in 1961. Senior faculty affiliating with LPL in the earliest years were T. Gehrels, A. B. Meinel, H. L. Johnson, and F. J. Low, each with their own grad students and associates. Work began on IR spectroscopy and a rectified lunar atlas. Kuiper and Johnson started the search for future observatory sites in N. America and Hawaii.

Origins of the Lunar and Planetary Laboratory, University of Arizona

NASA Astrophysics Data System (ADS)

Cruikshank, Dale P.; Hartmann, William K.

2014-11-01

The roots of the Lunar and Planetary Laboratory (LPL) extend deep into the rich fabric of G. P. Kuiper’s view of the Earth as a planet and planetary systems as expected companions to most stars, as well as the post-war emergent technology of infrared detectors suitable for astronomy. These concepts and events began with Kuiper’s theoretical work at Yerkes Observatory on the origin of the Solar System, his discovery of two planetary satellites and observational work with his near-infrared spectrometer on the then-new McDonald 82-inch telescope in the mid- to late-1940s. A grant for the production of a photographic atlas of the Moon in the mid-1950s enabled him to assemble the best existing images of the Moon and acquire new photographs. This brought E. A. Whitaker and D. W. G. Arthur to Yerkes. Others who joined in the lunar work were geologist Carl S. Huzzen and grad student E. P. Moore, as well as undergrad summer students A. B. Binder and D. P. Cruikshank (both in 1958). The Atlas was published in 1959, and work began on an orthographic lunar atlas. Kuiper’s view of planetary science as an interdisciplinary enterprise encompassing astronomy, geology, and atmospheric physics inspired his vision of a research institution and an academic curriculum tuned to the combination of all the scientific disciplines embraced in a comprehensive study of the planets. Arrangements were made with the University of Arizona (UA) to establish LPL in affiliation with the widely recognized Inst. of Atmospheric Physics. Kuiper moved to the UA in late 1960, taking the lunar experts, graduate student T. C. Owen (planetary atmospheres), and associate B. M. Middlehurst along. G. van Biesbroeck also joined the migration to Tucson; Binder and Cruikshank followed along as new grad students. Astronomy grad student W. K. Hartmann came into the academic program at UA and the research group at LPL in 1961. Senior faculty affiliating with LPL in the earliest years were T. Gehrels, A. B. Meinel, H. L. Johnson, and F. J. Low, each with their own grad students and associates. Work began on IR spectroscopy and a rectified lunar atlas. Kuiper and Johnson started the search for future observatory sites in N. America and Hawaii.

The Survival of Meteorite Organic Compounds with Increasing Impact Pressure

NASA Technical Reports Server (NTRS)

Cooper, George; Horz, Friedrich; Oleary, Alanna; Chang, Sherwood; DeVincenzi, Donald L. (Technical Monitor)

2000-01-01

The majority of carbonaceous meteorites studied today are thought to originate in the asteroid belt. Impacts among asteroidal objects generate heat and pressure that may have altered or destroyed pre-existing organic matter in both targets and projectiles to a greater or lesser degree depending upon impact velocities. Very little is known about the shock related chemical evolution of organic matter relevant to this stage of the cosmic history of biogenic elements and compounds. The present work continues our study of the effects of shock impacts on selected classes of organic compounds utilizing laboratory shock facilities. Our approach was to subject mixtures of organic compounds, embedded in a matrix of the Murchison meteorite, to a simulated hypervelocity impact. The molecular compositions of products were then analyzed to determine the degree of survival of the original compounds. Insofar as results associated with velocities < 8 km/sec may be relevant to impacts on planetary surfaces (e.g., oblique impacts, impacts on small outer planet satellites) or grain-grain collisions in the interstellar medium, then our experiments will be applicable to these environments as well.

Modeling the Entry of Micrometeoroids into the Atmospheres of Earth-like Planets

NASA Technical Reports Server (NTRS)

Pevyhouse, A. R.; Kress, M. E.

2011-01-01

The temperature profiles of micrometeors entering the atmospheres of Earth-like planets are calculated to determine the altitude at which exogenous organic compounds may be released. Previous experiments have shown that flash-heated micrometeorite analogs release organic compounds at temperatures from roughly 500 to 1000 K [1]. The altitude of release is of great importance because it determines the fate of the compound. Organic compounds that are released deeper in the atmosphere are more likely to rapidly mix to lower altitudes where they can accumulate to higher abundances or form more complex molecules and/or aerosols. Variables that are explored here are particle size, entry angle, atmospheric density profiles, spectral type of the parent star, and planet mass. The problem reduces to these questions: (1) How much atmosphere does the particle pass through by the time it is heated to 500 K? (2) Is the atmosphere above sufficient to attenuate stellar UV such that the mixing timescale is shorter than the photochemical timescale for a particular compound? We present preliminary results that the effect of the planetary and particle parameters have on the altitude of organic release.

Field repair of AH-16 helicopter window cutting assemblies

NASA Technical Reports Server (NTRS)

Bement, L. J.

1984-01-01

The U.S. Army uses explosively actuated window cutting assemblies to provide emergency crew ground egress. Gaps between the system's explosive cords and acrylic windows caused a concern about functional reliability for a fleet of several hundred aircraft. A field repair method, using room temperature vulcanizing silicone compound (RTV), was developed and demonstrated to fill gaps as large as 0.250 inch.

Dehydration of planetary ices at high pressure; the role of analogue materials (Invited)

NASA Astrophysics Data System (ADS)

Fortes, A. D.

2013-12-01

Many planet-forming compounds become unstable with respect to their components under conditions of high pressure. In the Earth, for example, Mg2SiO4 breaks down to MgSiO3 + MgO at ~ 25 GPa, a pressure corresponding to the 670 km seismic discontinuity, with significance for the dynamics of convective flow in the mantle. A similar phenomenon occurs with many hydrate compounds thought to be major ';rock forming minerals' inside outer Solar System bodies, undoubtedly with important consequences for the structure and dynamics of icy worlds. It is well known that clathrates tend to form denser polymorphs with an incrementally greater concentration of the guest molecule, exsolving high-pressure phases of water ice in the process, or else (in the case of CO2), break down to entirely to their component molecular solids. My own recent work using high-pressure neutron powder diffraction has explored not only the behaviour of methane clathrates but also the exsolution of water from ammonia dihydrate and monohydrate, both of which break down eventually to ammonia hemihydrate + ice. In some cases, understanding the sequence of changes in both crystal structure and composition at high pressure is challenging, particularly when the starting materials have a complex crystal structure. Some years ago, I identified a high-pressure phase boundary where MgSO4.11H2O (meridianiite) appeared to break down to another hydrate and high-pressure ice VI. However, the powder diffraction pattern of the hydrate formed under these conditions resembled nothing encountered previously in my high-pressure studies of the next lowest hydrate, MgSO4.7H2O (epsomite). This led me to search for hydration states between 7 and 11 which might have escaped detection over several centuries of study of simple divalent metal sulfates. A wide-ranging systematic study of M2+X6+O4.nH2O compounds at low temperatures uncovered two new hydrates, an 8-hydrate and a 9-hydrate, the former occurring only in NiSO4 solutions, and the latter being found in Ni-, Zn-, Cu-, and Fe-doped MgSO4 solutions. Indeed, I determined that small quantities of pure MgSO4.9H2O can co-crystallise at ambient pressure with meridianiite. However, these all appear to be metastable states, and further work was necessary to try and discover stable forms of these hydrates for further study. In experiments carried out earlier this year, evidence has emerged not only that MgMoO4 can form a (possibly) stable 8-hydrate but also that MgSeO4 can form a 9-hydrate that exists in equilibrium with liquid near the eutectic. These apparently esoteric compounds (from a planetary perspective) may yet hold the key to understanding the high-pressure behaviour of true planetary materials. Just as the search for analogue materials over many decades has substantially advanced our knowledge of Earth materials, similar analogue studies are poised to unlock the mysteries of these planetary ices.

Hydrogen bonding interactions and supramolecular assemblies in 2-amino guanidinium 4-methyl benzene sulphonate crystal structure: Hirshfeld surfaces and computational calculations

NASA Astrophysics Data System (ADS)

Muthuraja, P.; Joselin Beaula, T.; Balachandar, S.; Bena Jothy, V.; Dhandapani, M.

2017-10-01

2-aminoguanidinium 4-methyl benzene sulphonate (AGMS), an organic compound with big assembly of hydrogen bonding interactions was crystallized at room temperature. The structure of the compound was confirmed by FT-IR, NMR and single crystal X-ray diffraction analysis. Numerous hydrogen bonded interactions were found to form supramolecular assemblies in the molecular structure. Fingerprint plots of Hirshfeld surface analysis spells out the interactions in various directions. The molecular structure of AGMS was optimised by HF, MP2 and DFT (B3LYP and CAM-B3LYP) methods at 6-311G (d,p) basis set and the geometrical parameters were compared. Electrostatic potential calculations of the reactants and product confirm the transfer of proton. Optical properties of AGMS were ascertained by UV-Vis absorbance and reflectance spectra. The band gap of AGMS is found to be 2.689 eV. Due to numerous hydrogen bonds, the crystal is thermally stable up to 200 °C. Hyperconjugative interactions which are responsible for the second hyperpolarizabilities were accounted by NBO analysis. Static and frequency dependent optical properties were calculated at HF and DFT methods. The hyperpolarizabilities of AGMS increase rapidly at frequencies 0.0428 and 0.08 a.u. compared to static one. The compound exhibits violet and blue emission.

Upper Torso Control for HOAP-2 Using Neural Networks

NASA Technical Reports Server (NTRS)

Sandoval, Steven P.

2005-01-01

Humanoid robots have similar physical builds and motion patterns as humans. Not only does this provide a suitable operating environment for the humanoid but it also opens up many research doors on how humans function. The overall objective is replacing humans operating in unsafe environments. A first target application is assembly of structures for future lunar-planetary bases. The initial development platform is a Fujitsu HOAP-2 humanoid robot. The goal for the project is to demonstrate the capability of a HOAP-2 to autonomously construct a cubic frame using provided tubes and joints. This task will require the robot to identify several items, pick them up, transport them to the build location, then properly assemble the structure. The ability to grasp and assemble the pieces will require improved motor control and the addition of tactile feedback sensors. In recent years, learning-based control is becoming more and more popular; for implementing this method we will be using the Adaptive Neural Fuzzy Inference System (ANFIS). When using neural networks for control, no complex models of the system must be constructed in advance-only input/output relationships are required to model the system.

Synthesis and Evaluation of N-phenyl-3-sulfamoyl-benzamide Derivatives as Capsid Assembly Modulators inhibiting Hepatitis B Virus (HBV).

PubMed

Vandyck, Koen; Rombouts, Geert; Stoops, Bart; Tahri, Abdellah; Vos, Ann; Verschueren, Wim; Wu, Yiming; Yang, Jingmei; Hou, Fuliang; Huang, Bing; Vergauwen, Karen; Dehertogh, Pascale; Berke, Jan-Martin; Raboisson, Pierre Jean Marie Bernard

2018-06-15

Small molecule induced Hepatitis B virus (HBV) capsid assembly modulation is considered an attractive approach for new antiviral therapies against HBV. Here we describe efforts towards the discovery of a HBV capsid assembly modulator in a hit-to-lead optimization, resulting in JNJ-632, a tool compound used to further profile the mode of action. Administration of JNJ-632 (54) in HBV genotype D infected chimeric mice, resulted in a 2.77 log reduction of the HBV DNA viral load.

Process for producing elements from a fused bath using a metal strap and ceramic electrode body nonconsumable electrode assembly

DOEpatents

Byrne, S.C.

1984-07-03

A nonconsumable electrode assembly is described suitable for use in the production of metal by electrolytic reduction of a metal compound dissolved in a molten salt, the assembly comprising a ceramic electrode body and a metal subassembly of a metal conductor rod and at least one metal strap affixed to an end of the rod with opposing portions extending radially outwardly from the rod axis and having the ends of the strap attached to the electrode body. 7 figs.

"Artificial micro organs"--a microfluidic device for dielectrophoretic assembly of liver sinusoids.

PubMed

Schütte, Julia; Hagmeyer, Britta; Holzner, Felix; Kubon, Massimo; Werner, Simon; Freudigmann, Christian; Benz, Karin; Böttger, Jan; Gebhardt, Rolf; Becker, Holger; Stelzle, Martin

2011-06-01

In order to study possible toxic side effects of potential drug compounds in vitro a reliable test system is needed. Predicting liver toxicity presents a major challenge of particular importance as liver cells grown in a cell culture suffer from a rapid loss of their liver specific functions. Therefore we are developing a new microfluidic test system for liver toxicity. This test system is based on an organ-like liver 3D co-culture of hepatocytes and endothelial cells. We devised a microfluidic chip featuring cell culture chambers with integrated electrodes for the assembly of liver sinusoids by dielectrophoresis. Fluid channels enable an organ-like perfusion with culture media and test compounds. Different chamber designs were studied and optimized with regard to dielectrophoretic force distribution, hydrodynamic flow profile, and cell trapping rate using numeric simulations. Based on simulation results a microchip was injection-moulded from COP. This chip allowed the assembly of viable hepatocytes and endothelial cells in a sinusoid-like fashion.

Optically pure, water-stable metallo-helical ‘flexicate’ assemblies with antibiotic activity

NASA Astrophysics Data System (ADS)

Howson, Suzanne E.; Bolhuis, Albert; Brabec, Viktor; Clarkson, Guy J.; Malina, Jaroslav; Rodger, Alison; Scott, Peter

2012-01-01

The helicates—chiral assemblies of two or more metal atoms linked by short or relatively rigid multidentate organic ligands—may be regarded as non-peptide mimetics of α-helices because they are of comparable size and have shown some relevant biological activity. Unfortunately, these beautiful helical compounds have remained difficult to use in the medicinal arena because they contain mixtures of isomers, cannot be optimized for specific purposes, are insoluble, or are too difficult to synthesize. Instead, we have now prepared thermodynamically stable single enantiomers of monometallic units connected by organic linkers. Our highly adaptable self-assembly approach enables the rapid preparation of ranges of water-stable, helicate-like compounds with high stereochemical purity. One such iron(II) ‘flexicate’ system exhibits specific interactions with DNA, promising antimicrobial activity against a Gram-positive bacterium (methicillin-resistant Staphylococcus aureus, MRSA252), but also, unusually, a Gram-negative bacterium (Escherichia coli, MC4100), as well as low toxicity towards a non-mammalian model organism (Caenorhabditis elegans).

Influence of Oxygenated Compounds on Reaction Products in a Microwave Plasma Methane Pyrolysis Assembly for Post-Processing of Sabatier Methane

NASA Technical Reports Server (NTRS)

Mansell, J. Matthew; Abney, Morgan B.; Miller, Lee A.

2011-01-01

The state-of-the-art Carbon Dioxide Reduction Assembly (CRA) was delivered to the International Space Station (ISS) in April 2010. The system is designed to accept carbon dioxide from the Carbon Dioxide Removal Assembly and hydrogen from the Oxygen Generation Assembly. The two gases are reacted in the CRA in a Sabatier reactor to produce water and methane. Venting of methane results in an oxygen resupply requirement of about 378 lbs per crew member per year. If the oxygen is supplied as water, the total weight for resupply is about 476 lb per crew member per year. For long-term missions beyond low Earth orbit, during which resupply capabilities will be further limited, recovery of hydrogen from methane is highly desirable. For this purpose, NASA is pursuing development of a Plasma Pyrolysis Assembly (PPA) capable of recovering hydrogen from methane. Under certain conditions, water vapor and carbon dioxide (nominally intended to be separated from the CRA outlet stream) may be present in the PPA feed stream. Thus, testing was conducted in 2010 to determine the effect of these "oxygenated" compounds on PPA performance, particularly the effect of inlet carbon dioxide and water variations on the PPA product stream. This paper discusses the test set-up, analysis, and results of this testing

Luminescent Carbon Dot Mimics Assembled on DNA

PubMed Central

Chan, Ke Min; Xu, Wang; Kwon, Hyukin; Kietrys, Anna M.; Kool, Eric T.

2018-01-01

Nanometer-sized fragments of carbon in the form of multilayer graphene (“carbon dots”) have been under highly active study for applications in imaging. While offering advantages of low toxicity and photostability, such nanomaterials are inhomogeneous and have limited wavelengths of emission. Here we address these issues by assembling luminescent aromatic C16–C38 hydrocarbons together on a DNA scaffold in homogeneous, soluble molecular compounds. Monomer deoxyribosides of five different aromatic hydrocarbons were synthesized and assembled into a library of 1296 different tetramer compounds on PEG-polystyrene beads. These were screened for photostability and a range of emission colors using 365 nm excitation, observing visible light (>400 nm) emission. We identified a set of six oligomers (DNA-carbon assemblies, DNA-CAs) with exceptional photostability that emit from 400 to 680 nm in water, with Stokes shifts of up to 110 nm, quantum yields ranging from 0.01 to 0.29, and fluorescence lifetimes from 3 to 42 ns. In addition, several of these DNA-CAs exhibited white emission in aqueous solution. The molecules were used in multispectral cell imaging experiments and were taken up into cells passively. The results expand the range of emission properties that can be achieved in water with all-hydrocarbon chromophores and establish the use of the DNA scaffold to arrange carbon layers in homogeneous, rapidly synthesized assemblies. PMID:28841010

Influence of Oxygenated Compounds on Reaction Products in a Microwave Plasma Methane Pyrolysis Assembly for Post-Processing of Sabatier Methane

NASA Technical Reports Server (NTRS)

Mansell, J. Matthew; Abney, Morgan B.

2012-01-01

The state-of-the-art Carbon Dioxide Reduction Assembly (CRA) was delivered to the International Space Station (ISS) in April 2010. The system is designed to accept carbon dioxide from the Carbon Dioxide Removal Assembly and hydrogen from the Oxygen Generation Assembly. The two gases are reacted in the CRA in a Sabatier reactor to produce water and methane. Venting of methane results in an oxygen resupply requirement of about 378 lbs per crew member per year. If the oxygen is supplied as water, the total weight for resupply is about 476 lb per crew member per year. For long-term missions beyond low Earth orbit, during which resupply capabilities will be further limited, recovery of hydrogen from methane is highly desirable. For this purpose, NASA is pursuing development of a Plasma Pyrolysis Assembly (PPA) capable of recovering hydrogen from methane. Under certain conditions, water vapor and carbon dioxide (nominally intended to be separated from the CRA outlet stream) may be present in the PPA feed stream. Thus, testing was conducted in 2010 to determine the effect of these oxygenated compounds on PPA performance, particularly the effect of inlet carbon dioxide and water variations on the PPA product stream. This paper discusses the test set-up, analysis, and results of this testing.

[Study of physicochemical and bacteriological impact of a weekly assembly of automated compounding BAXA(®) Exacta-Mix 2400 on parenteral nutrition admixture manufacturing].

PubMed

Chappuy, L; Charroin, C; Vételé, F; Durand, T; Quessada, T; Klotz, M-C; Bréant, V; Aulagner, G

2014-01-01

The parenteral nutrition admixtures are manufactured with an automated compounding BAXA(®) Exacta-Mix 2400. A 48-hour assembly has been validated. To optimize time and cost, a weekly assembly was tested. Assembly was made on the first day. Ten identical parenteral nutrition admixtures (different volumes and compositions) were produced each day. A macroscopic examination was done at D0, D7 and D14. Physicochemical controls (electrolytes determinations by atomic absorption spectrophotometry, osmolalities measurements) were performed. Microbiological tests included a filtration membrane sterility test (Steritest(®)) and a plate count agar environmental monitoring. All mixtures were considered stable. The 12 Steritest(®) (H24, H48, D7 and D14) did not show any bacterial or fungal contamination. No microorganism has been detected on the plate count agar at D4 and D7. Concerning the physicochemical parameters of each parental nutrition admixture, no significant difference (Wilcoxon test) with the first day was found. The automated filling system BAXA(®) Exacta-Mix 2400 improves the quality and safety of production. According to these results, the weekly assembly is validated and permit to save time (80hours/year) and cost (40 000 euros on consumable/year). Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Novel self-assembled mesalamine-sucralfate complexes: preparation, characterization, and formulation aspects.

PubMed

Ispas-Szabo, Pompilia; Friciu, Mihaela Maria; Nguyen, Phuong; Dumoulin, Yves; Mateescu, Mircea Alexandru

2016-01-01

Two well-known active agents, mesalamine (MES) and sucralfate (SUC), were investigated for possible utilization as fixed-dose combination product. The anti-inflammatory action of MES in association with bioadhesiveness and mucosal healing properties of SUC were considered promising for the development of a new compound containing both molecules, aimed as an improved treatment of ulcerative colitis. The present study investigates the capacity of the two active agents to interact and generate a new and stable entity via self-assembling. Spray-drying was used to co-process the two active principles from an aqueous mixture where the ratio MES:SUC was in the range 25:75, 50:50, and 75:25. The structural data (X-Ray, FTIR, SEM, DSC, and (1)H NMR) have shown that MES and SUC are interacting leading to complexes with properties differing from those of each separate active agent and from their physical blends. (1)H NMR results indicated that complexation occurred when the aqueous suspensions of drugs were mixed, prior to spray-drying. Drug-drug self-assembling was the driving mechanism in the formation of the new entity. Based on the structural data, a hypothetical structure of the complex was proposed. Co-processing of MES and SUC represents a simple and useful procedure to prepare new self-assembled compounds by valorizing the ionic interactions between the two entities. Preliminary studies with oral solid dosage forms based on MES-SUC complexes tested in vitro have shown a controlled MES release, opening the perspective of a new colon-targeted delivery system and a novel class of compounds with therapeutic application in inflammatory bowel diseases.

Cleaning-resistant Cupriavidus and Ralstonia bacteria contaminating spacecrafts and the ultra clean rooms they are assembled in.

NASA Astrophysics Data System (ADS)

Leys, N.; Dams, A.; Bossus, A.; Provoost, A.; Venkateswaran, K.; Mergeay, M.

Background Planetary Protection is preventing microbial contamination of both the target planet and the Earth when sending spacecrafts on interplanetary space mission It is important to preserve the natural conditions of other planets and to not bring with robots earthly microbes forward contamination when looking for spores of extra terrestrial life Spacecrafts and the ultra clean rooms they are assembled in are routinely monitored for microbial contamination It was shown that the floor air and surfaces of such spacecraft assembly rooms often contain Cupriavidu s and Ralstonia bacteria These bacteria not only contaminated the clean rooms but have also been found prior-to-flight on surfaces of space robots such as the Mars Odyssey Orbiter La Duc et al 2003 and even in-flight in ISS cooling water and Shuttle drinking water unpublished Aim In this study several Cupriavidus and Ralstonia strains isolated from space craft assembling rooms and spacecrafts were characterized and analysed in detail Results The analysis showed that all the Cupriavidus and Ralstonia clean-room isolates are able to use a wide variety of substrates as carbon sources including ethanol and acetone In addition they all have accumulated moderate resistances to an extraordinary collection of physical and chemical antimicrobial agents Some of the test strains were able to form biofilms on plastic and metal materials used for space robots a nutritional and

Observation of martensitic transformation in Ni50Mn41Cu4Sn5 Heusler alloy prepared by mechanical alloying

NASA Astrophysics Data System (ADS)

Saini, Dinesh; Singh, Satyavir; Banerjee, M. K.; Sachdev, K.

2017-05-01

Mechanical alloying route has been employed for preparation of a single phase Ni50Mn41Cu4Sn5 (atomic %) Heusler alloy. Use of high energy planetary ball mill enables successful preparation of the same as authenticated by detailed X-ray diffraction (XRD) study. Microstructural study is carried out by optical and scanning electron microscopic techniques. XRD results reveal that increasing milling time leads to reduction in crystallite size and concurrent increase in lattice strain. Microstructural results indicate formation of self-assembled martensite twins.

STS-30 Magellan spacecraft is unpacked at Kennedy Space Center (KSC) SAEF-2

NASA Technical Reports Server (NTRS)

1989-01-01

At the Kennedy Space Center (KSC) inside the Space Assembly and Encapsulation Facility 2 (SAEF-2) (planetary checkout facility), the cover of the Payload Environmental Transportation System (PETS) is removed so that the Magellan spacecraft can be hoisted from the PETS trailer to the clean room floor. Clean-suited technicians guide the cover above plastic-wrapped spacecraft using rope. The spacecraft, destined for unprecedented studies of the Venusian topographic features, is to be deployed by the crew of NASA STS-30 mission in April 1989. View provided by KSC with alternate number KSC-88PC-1083.

Planetary ecology; Proceedings of the Sixth International Symposium on Environmental Biogeochemistry, Santa Fe, NM, October 10-14, 1983

NASA Technical Reports Server (NTRS)

Caldwell, D. E. (Editor); Brierley, J. A. (Editor); Brierley, C. L. (Editor)

1985-01-01

Topics presented include biological evolution and planetary chemistry; C-1 compounds; transport, deposition, and weathering; sulfur transformations; ground water; transformation processes for nitrogen oxides; and soils. Papers are presented on immunological studies on the organic matrix of recent and fossil invertebrate shells; biogenic gases in sediments deposited since Miocene times on the Walvis Ridge, South Atlantic Ocean; aspects of the biogeochemistry of Big Soda Lake, NV; mesophilic manganese-oxidizing bacteria from hydrothermal discharge areas at 21 deg North on the East Pacific Rise; and autotrophic growth and iron oxidation and inhibition kinetics of Leptospirillum ferrooxidans. Consideration is also given to thermophilic archaebacteria occurring in submarine hydrothermal areas; fate of sulfate in a soft-water, acidic lake; geochemical conditions in the ground water environment; microbial transformations as sources and sinks for nitrogen oxides; and the biogeochemistry of soil phosphorus.

Classification of Ion Mobility Data Using the Neural Network Approach

NASA Technical Reports Server (NTRS)

Duong, T. A.; Kanik, I.

2005-01-01

Determination of atmospheric and surface elemental and molecular composition of various solar system bodies is essential to the development of a firm understanding of the origin and evolution of the solar system. Furthermore, such data is needed to address the intriguing question of whether or not life exists or once existed elsewhere in the Solar System. As such, these measurements are among the primary scientific goals of NASA s current and future planetary missions. In recent years, significant progress toward both miniaturization and field portability of in situ analytical separation and detection devices have been made with future planetary explorations in mind. However, despite all these advances, accurate in situ identification of atmospheric and surface compounds remains a big challenge. In response to that we are developing various hardware and software tools which would enable us to uniquely identify species of interest in a complex chemical environment.

Comparison of methods for measurement of organic compounds at ultra-trace level: analytical criteria and application to analysis of amino acids in extraterrestrial samples.

PubMed

Vandenabeele-Trambouze, O; Claeys-Bruno, M; Dobrijevic, M; Rodier, C; Borruat, G; Commeyras, A; Garrelly, L

2005-02-01

The need for criteria to compare different analytical methods for measuring extraterrestrial organic matter at ultra-trace levels in relatively small and unique samples (e.g., fragments of meteorites, micrometeorites, planetary samples) is discussed. We emphasize the need to standardize the description of future analyses, and take the first step toward a proposed international laboratory network for performance testing.

History of Hubble Space Telescope (HST)

NASA Image and Video Library

1985-01-01

In this photograph, engineers and technicians prepare the Hubble Space Telescope's (HST's) Wide Field and Planetary Camera (WF/PC) for installation at the Lockheed Missile and Space Company. The WF/PC is designed to investigate the age of the universe and to search for new planetary systems around young stars. It takes pictures of large numbers of galaxies and close-ups of planets in our solar system. The HST is the first of NASA's great observatories and the most complex and sensitive optical telescope ever made. The purpose of the HST is to study the cosmos from a low-Earth orbit by placing the telescope in space, enabling astronomers to collect data that is free of the Earth's atmosphere. The HST was deployed from the Space Shuttle Discovery (STS-31 mission) into Earth orbit in April 1990. The Marshall Space Flight Center had overall responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Cornecticut, developed the optical system and guidance sensors. The Lockheed Missile and Space Company, Sunnyvale, California, produced the protective outer shroud and spacecraft systems, and assembled and tested the finished telescope.

Determination of Aromatic Ring Number Using Multi-Channel Deep UV Native Fluorescence

NASA Technical Reports Server (NTRS)

Bhartia, R.; McDonald, G. D.; Salas, E.; Conrad, P.

2004-01-01

The in situ detection of organic material on an extraterrestrial surface requires both effective means of searching a relatively large surface area or volume for possible organic carbon, and a more specific means of identifying and quantifying compounds in indicated samples. Fluorescence spectroscopy fits the first requirement well, as it can be carried out rapidly, with minimal or no physical contact with the sample, and with sensitivity unmatched by any other organic analytical technique. Aromatic organic compounds with know fluorescence signatures have been identified in several extraterrestrial samples, including carbonaceous chondrites, interplanetary dust particles, and Martian meteorites. The compound distributions vary among these sources, however, with clear differences in relative abundances by number of aromatic rings and by degree of alkylation. This relative abundance information, therefore, can be used to infer the source of organic material detected on a planetary surface.

On the formation of molecules and solid-state compounds from the AGB to the PN phases

NASA Astrophysics Data System (ADS)

García-Hernández, D. A.; Manchado, A.

2016-07-01

During the asymptoyic giant branch (AGB) phase, different elements are dredge- up to the stellar surface depending on progenitor mass and metallicity. When the mass loss increases at the end of the AGB, a circumstellar dust shell is formed, where different (C-rich or O-rich) molecules and solid-state compounds are formed. These are further processed in the transition phase between AGB stars and planetary nebulae (PNe) to create more complex organic molecules and inorganic solid-state compounds (e.g., polycyclic aromatic hydrocarbons, fullerenes, and graphene precursors in C-rich environments and oxides and crystalline silicates in O-rich ones). We present an observational review of the different molecules and solid-state materials that are formed from the AGB to the PN phases. We focus on the formation routes of complex fullerene (and fullerene-based) molecules as well as on the level of dust processing depending on metallicity.

CONTROL OF INDUSTRIAL VOC (VOLATILE ORGANIC COMPOUND) EMISSIONS BY CATALYTIC INCINERATION. VOLUME 8. CATALYTIC INCINERATOR PERFORMANCE AT INDUSTRIAL SITE C-6

EPA Science Inventory

The report is part of a two-phase EPA effort to assess the performance, suitability, and costs of various technologies to control emissions of volatile organic compounds (VOCs). In Phase 1, information was assembled from the literature on the use and cost of using catalytic incin...

CONTROL OF INDUSTRIAL VOC (VOLATILE ORGANIC COMPOUND) EMISSIONS BY CATALYTIC INCINERATION. VOLUME 1. ASSESSMENT OF CATALYTIC INCINERATION AND COMPETING CONTROLS

EPA Science Inventory

The report is part of a two-phase EPA effort to assess the performance, suitability, and costs of various technologies to control emissions of volatile organic compounds (VOCs). In Phase 1, information was assembled from the literature on the use and cost of using catalytic incin...

CONTROL OF INDUSTRIAL VOC (VOLATILE ORGANIC COMPOUND) EMISSIONS BY CATALYTIC INCINERATION. VOLUME 7. CATALYTIC INCINERATOR PERFORMANCE AT INDUSTRIAL SITE C-5

EPA Science Inventory

The report is part of a two-phase EPA effort to assess the performance, suitability, and costs of various technologies to control emissions of volatile organic compounds (VOCs). In Phase 1, information was assembled from the literature on the use and cost of using catalytic incin...

CONTROL OF INDUSTRIAL VOC (VOLATILE ORGANIC COMPOUND) EMISSIONS BY CATALYTIC INCINERATION. VOLUME 5. CATALYTIC INCINERATOR PERFORMANCE AT INDUSTRIAL SITE C-3

EPA Science Inventory

The report is part of a two-phase EPA effort to assess the performance, suitability, and costs of various technologies to control emissions of volatile organic compounds (VOCs). In Phase 1, information was assembled from the literature on the use and cost of using catalytic incin...

Inverted cucurbit[6]uril supramolecular assemblies formed in the presence of tetrachlorozincate anions

NASA Astrophysics Data System (ADS)

Chen, Kai; Xu, Jing; Qiu, Sheng-Chao; Wang, Yuan; Chen, Min-Dong; Zhang, Yun-Qian; Xiao, Xin; Tao, Zhu

2017-10-01

We investigated the interactions in an inverted cucurbit[6]uril (iQ[6]) with a series of 1,ω-alkyldimins and their supramolecular assemblies in the presence of the tetrachlorozincate anion ([ZnCl4]2-) structure directing agent. iQ[6] forms an outer surface interaction with [ZnCl4]2- to form different iQ[6]/[ZnCl4]2--based supramolecular assemblies with different length 1,ω-alkyldimins. Interestingly, most 1,ω-alkyldimins were not visible in crystals structures in the presence of concentrated HCl. The porous iQ[6]/[ZnCl4]2--based supramolecular assemblies could be used as materials for adsorbing volatile compounds.

A novel compound inhibits rHDL assembly and blocks nascent HDL biogenesis downstream of apoAI binding to ABCA1 expressing cells

PubMed Central

Lyssenko, Nicholas N.; Brubaker, Gregory; Smith, Bradley D.; Smith, Jonathan D.

2011-01-01

Objective Nascent high-density lipoprotein (HDL) particles form from cellular lipids and extracellular lipid-free apolipoprotein AI (apoAI) in a process mediated by ATP-binding cassette transporter A1 (ABCA1). We have sought out compounds that inhibit nascent HDL biogenesis without affecting ABCA1 activity. Methods and Results Reconstituted HDL (rHDL) formation and cellular cholesterol efflux assays were used to show that two compounds that bond via hydrogen with phospholipids inhibit rHDL and nascent HDL production. In rHDL formation assays, the inhibitory effect of compound 1 (methyl 3α-acetoxy-7α,12α-di[(phenylaminocarbonyl)amino]-5β-cholan-24-oate), the more active of the two, depended on its ability to associate with phospholipids. In cell assays, compound 1 suppressed ABCA1-mediated cholesterol efflux to apoAI, the 18A peptide, and taurocholate with high specificity, without affecting ABCA1-independent cellular cholesterol efflux to HDL and endocytosis of acetylated low-density lipoprotein (AcLDL) and transferrin. Furthermore, compound 1 did not affect ABCA1 activity adversely, as ABCA1-mediated shedding of microparticles proceeded unabated and apoAI binding to ABCA1-expressing cells increased in its presence. Conclusions The inhibitory effects of compound 1 support a three-step model of nascent HDL biogenesis: plasma membrane remodeling by ABCA1, apoAI binding to ABCA1, and lipoprotein particle assembly. The compound inhibits the final step, causing accumulation of apoAI in ABCA1-expressing cells. PMID:21836073

Synthesis and characterization of sugar based low molecular weight gelators and the preparation of chiral sulfinamides

NASA Astrophysics Data System (ADS)

Mangunuru, Hari Prasad Reddy

Low molecular weight gelators (LMWGs) have received considerable attention in the field of chemistry from last few decades. These compounds form self-assembled fibrous networks like micelles, cylindrical, sheets, fibers, layers and so on. The fibrous network entraps the solvent and forms gel, because of the self-assembly phenomenon and their demonstrated potential uses in a variety of areas, ranging from environmental to medicinal applications. Sugars are good starting materials to synthesize the new class of LMWG's, because these are different from some expensive materials, these are natural products. We have synthesized and characterized the LMGS's based on D-glucose and D-glucosamine. D-glucosamine is the versatile starting material to make different peptoids and triazoles. Several series of compounds were synthesized using compounds 1-3 as starting material and studied the gelation behavior all the compounds. We have studied the self-assembling properties of a new class of tripeptoids, synthesized by one-pot Ugi reaction from simple starting materials. Among the focused library of tripeptoids synthesized, we found that several efficient low molecular weight organogelators were obtained for aqueous DMSO and ethanol mixtures. We have also synthesized and characterized a series of monosaccharide triazole derivatives. These compounds were synthesized from N-acetyl glucosamine and D-glucose via a Cu(I) catalyzed azide/alkyne cycloaddition reaction (CuAAc). The compounds have been screened for their gelation properties and several efficient low molecular weight organo/hydro gelators were obtained, among these compounds, five per-acetyl glucosamine derivatives and one peracetyl glucose derivative were able to form gels in water. These new molecules are expected to be useful in drug delivery and tissue engineering.*. Asymmetric synthesis of chiral amines is a challenging in synthetic organic chemistry. The development of new catalysts for asymmetric organic transformations is a very important research goal in modern synthetic organic chemistry. We have synthesized a new class of chiral oxathiozinone from chiral amino phenol. From this synthesized chiral sulfinamides, ketimines followed by reducing the ketimines synthesized the highly hindered chiral amines. *Please refer to dissertation for diagrams.

Transition Metal Compounds Towards Holography

PubMed Central

Dieckmann, Volker; Eicke, Sebastian; Springfeld, Kristin; Imlau, Mirco

2012-01-01

We have successfully proposed the application of transition metal compounds in holographic recording media. Such compounds feature an ultra-fast light-induced linkage isomerization of the transition-metal–ligand bond with switching times in the sub-picosecond regime and lifetimes from microseconds up to hours at room temperature. This article highlights the photofunctionality of two of the most promising transition metal compounds and the photophysical mechanisms that are underlying the hologram recording. We present the latest progress with respect to the key measures of holographic media assembled from transition metal compounds, the molecular embedding in a dielectric matrix and their impressive potential for modern holographic applications. PMID:28817028

Characterization of a Novel Type of HIV-1 Particle Assembly Inhibitor Using a Quantitative Luciferase-Vpr Packaging-Based Assay

PubMed Central

Errazuriz, Elisabeth; Coric, Pascale; Souquet, Florence; Turcaud, Serge; Boulanger, Pierre; Bouaziz, Serge; Hong, Saw See

2011-01-01

The HIV-1 auxiliary protein Vpr and Vpr-fusion proteins can be copackaged with Gag precursor (Pr55Gag) into virions or membrane-enveloped virus-like particles (VLP). Taking advantage of this property, we developed a simple and sensitive method to evaluate potential inhibitors of HIV-1 assembly in a living cell system. Two proteins were coexpressed in recombinant baculovirus-infected Sf9 cells, Pr55Gag, which formed the VLP backbone, and luciferase fused to the N-terminus of Vpr (LucVpr). VLP-encapsidated LucVpr retained the enzymatic activity of free luciferase. The levels of luciferase activity present in the pelletable fraction recovered from the culture medium correlated with the amounts of extracellular VLP released by Sf9 cells assayed by conventional immunological methods. Our luciferase-based assay was then applied to the characterization of betulinic acid (BA) derivatives that differed from the leader compound PA-457 (or DSB) by their substituant on carbon-28. The beta-alanine-conjugated and lysine-conjugated DSB could not be evaluated for their antiviral potentials due to their high cytotoxicity, whereas two other compounds with a lesser cytotoxicity, glycine-conjugated and ε-NH-Boc-lysine-conjugated DSB, exerted a dose-dependent negative effect on VLP assembly and budding. A fifth compound with a low cytotoxicity, EP-39 (ethylene diamine-conjugated DSB), showed a novel type of antiviral effect. EP-39 provoked an aberrant assembly of VLP, resulting in nonenveloped, morula-like particles of 100-nm in diameter. Each morula was composed of nanoparticle subunits of 20-nm in diameter, which possibly mimicked transient intermediates of the HIV-1 Gag assembly process. Chemical cross-linking in situ suggested that EP-39 favored the formation or/and persistence of Pr55Gag trimers over other oligomeric species. EP-39 showed a novel type of negative effect on HIV-1 assembly, targeting the Pr55Gag oligomerisation. The biological effect of EP-39 underlined the critical role of the nature of the side chain at position 28 of BA derivatives in their anti-HIV-1 activity. PMID:22073298

Science with the James Webb Space Telescope

NASA Technical Reports Server (NTRS)

Gardner, Jonathan P.

2011-01-01

The scientific capabilities of the James Webb Space Telescope (JWST) fall into four themes. The End of the Dark Ages: First Light and Reionization theme seeks to identify the first luminous sources to form and to determine the ionization history of the universe. The Assembly of Galaxies theme seeks to determine how galaxies and the dark matter, gas, stars, metals, morphological structures, and active nuclei within them evolved from the epoch of reionization to the present. The Birth of Stars and Protoplanetary Systems theme seeks to unravel the birth and early evolution of stars, from infall onto dust-enshrouded protostars, to the genesis of planetary systems. The Planetary Systems and the Origins of Life theme seeks to determine the physical and chemical properties of planetary systems around nearby stars and of our own, and investigate the potential for life in those systems. To enable these for science themes, JWST will be a large (6.6m) cold (50K) telescope in orbit around the second Earth-Sun Lagrange point. It is the successor to the Hubble and Spitzer Space Telescopes, and is a partnership of NASA, ESA and CSA. JWST will have four instruments: The Near-Infrared Camera, the Near-Infrared multi-object Spectrograph, and the Tunable Filter Imager will cover the wavelength range 0.6 to 5 microns, while the Mid-Infrared Instrument will do both imaging and spectroscopy from 5 to 28.5 microns. I will conclude the talk with a description of recent technical progress in the construction of the observatory.

Science with the James Webb Space Telescope

NASA Technical Reports Server (NTRS)

Gardner, Jonathan P.

2006-01-01

The scientific capabilities of the James Webb Space Telescope (JWST) fall into four themes. The End of the Dark Ages: First Light and Reionization theme seeks to identify the first luminous sources to form and to determine the ionization history of the universe. The Assembly of Galaxies theme seeks to determine how galaxies and the dark matter, gas, stars, metals, morphological structures, and active nuclei within them evolved from the epoch of reionization to the present. The Birth of Stars and Protoplanetary Systems theme seeks to unravel the birth and early evolution of stars, from infall onto dust-enshrouded protostars, to the genesis of planetary systems. The Planetary Systems and the Origins of Life theme seeks to determine the physical and chemical properties of planetary systems around nearby stars and of our own, and investigate the potential for life in those systems. To enable these for science themes, JWST will be a large (6.5m) cold (50K) telescope launched to the second Earth-Sun Lagrange point early in the next decade. It is the successor to the Hubble Space Telescope, and is a partnership of NASA, ESA and CSA. JWST will have three instruments: The Near-Infrared Camera, and the Near-Infrared multi-object Spectrograph will cover the wavelength range 0.6 to 5 microns, while the Mid-Infrared Instrument will do both imaging and spectroscopy from 5 to 27 microns. I review the status and capabilities of the observatory and instruments in the context of the major scientific goals.

The James Webb Space Telescope: Extending the Science

NASA Technical Reports Server (NTRS)

Gardner, Jonathan P.

2012-01-01

The science objectives of the James Webb Space Telescope fall into four themes. The End of the Dark Ages: First Light and Reionization theme seeks to identify the first luminous sources to form and to determine the ionization history of the universe. The Assembly of Galaxies theme seeks to determine how galaxies and the dark matter, gas, stars, metals, morphological structures, and black holes within them evolved from the epoch of reionization to the present. The Birth of Stars and Protoplanetary Systems theme seeks to unravel the birth and early evolution of stars, from infall onto dust-enshrouded protostars, to the genesis of planetary systems. The Planetary Systems and the Origins of Life theme seeks. to determine the physical and chemical properties of planetary systems around nearby stars and of our own, and to investigate the potential for life in those systems. These four science themes were used to establish the design requirements for the observatory and instrumentation. Since Webb's capabilities are unique, those science themes will remain relevant through launch and operations and goals contained within these themes will continue to guide the design and implementation choices for the mission. More recently, it has also become clear that Webb will make major contributions to other areas of research, including dark energy, dark matter, exoplanet characterization and Solar System objects. In this paper, I review the original four science themes and discuss how the scientific output of Webb will extend to these new areas of research.

Supramolecular assembly in the epiisopiloturine hydrochloride salt

NASA Astrophysics Data System (ADS)

Mafud, Ana Carolina; Reinheimer, Eric W.; Lima, Filipe Camargo Dalmatti Alves; Batista, Larissa Fernandes; de Paula, Karina; Véras, Leiz Maria Costa; de Souza de Almeida Leite, José Roberto; Venancio, Tiago; Mascarenhas, Yvonne Primerano

2017-05-01

Epiisopiloturine hydrochloride (Epi-HCl) salt was synthetized from epiisopiloturine, an in vivo anthelmintic compound against Schistosoma mansoni worms. Despite there being no acute toxicity in mammalian cells, the compound's water insolubility makes its administration difficult. In this communication, we report the characterization of Epi-HCl its features by spectroscopy, thermal analysis, and PXRD. The single crystals suitable to X-ray diffraction were grown by slow evaporation technique. To better understand the nature of Epi-HCl' solid state, SS-NMR was also used. The salt's intramolecular structure was maintained via cation-pi intramolecular interactions, which in conjunction with hydrogen bonding, gives rise to an extended supramolecular assembly. The interatomic distances within the cations and environment around the chloride anion vary as function of temperature, suggesting a packing relaxation.

Criteria for the emergence and evolution of life in the solar system.

PubMed

Oró, J; Rewers, K; Odom, D

1982-09-01

During the past years we have explored most of the bodies of the solar system by means of the Apollo, Venera, Viking, Voyager, and other space missions. We are now in a better position to be able to compare the conditions of other planets and satellites with those of the Earth in order to determine what is unique about our planet which permitted the emergence and evolution of life on it. On the basis of this and other available scientific information we have arrived at the conclusion that there are at least some twentyfive specific conditions or requirements which have to be fulfilled in order for life as we know it to appear and evolve in a planetary system such as ours. Most of these necessary conditions or requirements are mutually interdependent, but in order to discuss their role in depth they have been divided into five major general areas which are discussed in some detail herein. Planetary criteria, which relate to the physical properties of the planet as it is formed and as it becomes a differentiated cosmic body and potential abode of life. The mass, orbital characteristics and energetic relationships with the central star as well as the discrete separation of gas, liquid and solid phases of the planet are of utmost importance. Chemical criteria, which are concerned with the composition, availability of effective energy sources, and chemical constraints (solvent, pH range, redox potential) of the environment(s) where reactions take place for the prebiological formation of biochemical compounds. Protobiological criteria, which relate to the prebiologically synthesized oligomeric and polymeric biomolecules, how they interact cooperatively to form protobiological structures and functions (replication, catalysis, information transfer, etc.) and self-assemble to give rise to a living system. Evolutionary criteria, which are concerned with the processes responsible for the increase in complexity of organisms by genomic multiplication, symbiotic integration and cellular differentiation, as well as with the negentropic ability of organisms to continuously recycle all the volatile biogenic elements. Altogether these processes made possible the development and evolution of life from the simplest prokaryotic cell ancestor to a cognitive and manipulative multicellular organism (man). In order to extend this inquiry to other systems beyond our solar system a fifth set of requirements based on astronomical observations is also discussed, namely, the Stellar criteria, which relate to the elemental composition mass, lifetime, and other features of Main Sequence stars which may be surrounded by planetary systems similar to our own. Finally, a brief review is made on the probability of the existence of extraterrestrial life as well as of civilizations capable of interstellar communication in our Galaxy.

Formation and Internal Structure of Terrestrial Planets, and Atmospheric Escape

NASA Astrophysics Data System (ADS)

Jin, S.

2014-11-01

As of 2014 April 21, over 1490 confirmed exoplanets and 3705 Kepler candidates have been detected. This implies that exoplanets may be ubiquitous in the universe. In this paper, we focus on the formation, evolution, and internal structure of terrestrial planets, and the atmospheric escape of close-in planets. In chapter 2, we investigate the dynamical evolution of planetary system after the protoplanetary disk has dissipated. We find that in the final assembly stage, the occurrence of terrestrial planets is quite common and in 40% of our simulations finally at least one planet is formed in the habitable zone. We also find that if there is a highly-inclined giant planet in the system, a great many bodies will be either driven out of the system, or collide with the giant planet or the central star. This will lead to the difficulty in planetary accretion. Moreover, our results show that planetary migration can lead to the formation of close-in planets. Besides migration, close-in terrestrial planets can also be formed by a collision-merger mechanism, which means that planetary embryos can kick terrestrial planets directly into orbits that are extremely close to their parent stars. In chapter 3, we construct numerically an internal structure model for terrestrial planets, and provide three kinds of possible internal structures of Europa (Jupiter's moon) based on this model. Then, we calculate the radii of low-mass exoplanets for various mass combinations of core and mantle, and find that some of them are inconsistent with the observed radius of rocky planets. This phenomenon can be explained only if there exists a large amount of water in the core, or they own gaseous envelopes. In chapter 4, we improve our planetary evolution codes using the semi-gray model of Guillot (2010), which includes the incident flux from the host star as a heating source in planetary atmosphere. The updated codes can solve the structure of the top radiative zone of intensely irradiated planets, and thus can simulate the atmospheric escape of close-in planets driven by strong stellar X-ray or EUV emissions. We find that low-mass planets are sensitive to the atmospheric escape, and they could lose all their initial H/He envelopes during the evolution. On the other hand, gas giant can only lose a small fraction of their initial envelopes. We then carry out a parameter study of atmospheric escape at the planetary core mass, envelope mass fraction, and semi-major axis space. We find that the most intense phase of evaporation occurs within the early 100 Myr. Afterwards, atmospheric escape only has a small impact on the planetary evolution. In chapter 5, we apply our new planetary evolution model to different synthetic planet populations that are directly produced by the core-accretion paradigm (Mordasini et al. 2012a,b). We show that although the mass distribution of the planet populations is hardly affected by evaporation, the radius distribution clearly shows a break around 2 R_{⊕}. This break leads to a bimodal distribution in planet sizes (Owen & Wu 2013). Furthermore, the bimodal distribution is related to the initial characteristics of the planetary populations. We find that in two extreme cases, namely without any evaporation or with a 100% heating efficiency in the evaporation model, the final radius distributions show significant differences compared to the radius distribution of Kepler candidates. In chapter 6, we introduce a radiative transfer model that can calculate the radiation spectrum of close-in exoplanets.

Contextualising and Analysing Planetary Rover Image Products through the Web-Based PRoGIS

NASA Astrophysics Data System (ADS)

Morley, Jeremy; Sprinks, James; Muller, Jan-Peter; Tao, Yu; Paar, Gerhard; Huber, Ben; Bauer, Arnold; Willner, Konrad; Traxler, Christoph; Garov, Andrey; Karachevtseva, Irina

2014-05-01

The international planetary science community has launched, landed and operated dozens of human and robotic missions to the planets and the Moon. They have collected various surface imagery that has only been partially utilized for further scientific purposes. The FP7 project PRoViDE (Planetary Robotics Vision Data Exploitation) is assembling a major portion of the imaging data gathered so far from planetary surface missions into a unique database, bringing them into a spatial context and providing access to a complete set of 3D vision products. Processing is complemented by a multi-resolution visualization engine that combines various levels of detail for a seamless and immersive real-time access to dynamically rendered 3D scenes. PRoViDE aims to (1) complete relevant 3D vision processing of planetary surface missions, such as Surveyor, Viking, Pathfinder, MER, MSL, Phoenix, Huygens, and Lunar ground-level imagery from Apollo, Russian Lunokhod and selected Luna missions, (2) provide highest resolution & accuracy remote sensing (orbital) vision data processing results for these sites to embed the robotic imagery and its products into spatial planetary context, (3) collect 3D Vision processing and remote sensing products within a single coherent spatial data base, (4) realise seamless fusion between orbital and ground vision data, (5) demonstrate the potential of planetary surface vision data by maximising image quality visualisation in 3D publishing platform, (6) collect and formulate use cases for novel scientific application scenarios exploiting the newly introduced spatial relationships and presentation, (7) demonstrate the concepts for MSL, (9) realize on-line dissemination of key data & its presentation by a web-based GIS and rendering tool named PRoGIS (Planetary Robotics GIS). PRoGIS is designed to give access to rover image archives in geographical context, using projected image view cones, obtained from existing meta-data and updated according to processing results, as a means to interact with and explore the archive. However PRoGIS is more than a source data explorer. It is linked to the PRoVIP (Planetary Robotics Vision Image Processing) system which includes photogrammetric processing tools to extract terrain models, compose panoramas, and explore and exploit multi-view stereo (where features on the surface have been imaged from different rover stops). We have started with the Opportunity MER rover as our test mission but the system is being designed to be multi-mission, taking advantage in particular of UCL MSSL's PDS mirror, and we intend to at least deal with both MER rovers and MSL. For the period of ProViDE until end of 2015 the further intent is to handle lunar and other Martian rover & descent camera data. The presentation discusses the challenges of integrating rover and orbital derived data into a single geographical framework, especially reconstructing view cones; our human-computer interaction intentions in creating an interface to the rover data that is accessible to planetary scientists; how we handle multi-mission data in the database; and a demonstration of the resulting system & its processing capabilities. The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 312377 PRoViDE.

Primers of glycosaminoglycan biosynthesis from Peruvian rain forest plants.

PubMed

Taylor, W H; Sinha, A; Khan, I A; McDaniel, S T; Esko, J D

1998-08-28

We have developed a rapid, high throughput screening assay for compounds that alter the assembly of glycosaminoglycan chains in Chinese hamster ovary cells. The assay uses autoradiography to measure the binding of newly synthesized [35S]proteoglycans and [35S]glycosaminoglycans to a positively charged membrane. Screening over 1000 extracts from a random plant collection obtained from the Amazon rain forest yielded five plants that stimulated glycosaminoglycan assembly in both wild-type cells and a mutant cell line defective in xylosyltransferase (the first committed enzyme involved in glycosaminoglycan biosynthesis). Fractionation of an extract of Maieta guianensis by silica gel and reverse-phase chromatography yielded two pure compounds with stimulatory activity. Spectroscopic analysis by NMR and mass spectrometry revealed that the active principles were xylosides of dimethylated ellagic acid. One of the compounds also contained a galloyl group at C-3 of the xylose moiety. These findings suggest that plants and other natural products may be a source of agents that can potentially alter glycosaminoglycan and proteoglycan formation in animal cells.

Surface activity of branched alkylamino-compounds and their influence on phase transfer behavior in water solutions of dyes

NASA Astrophysics Data System (ADS)

Li, Cuiqin; Guo, Suyue; Lin, Zhiyu; Wang, Jun; Ge, Tengjie

2016-02-01

Two branched alkylamino-compounds (AAC, R12-0.5G, and R12-1.0G), were synthesized from dodecylamine, methyl acrylate and ethylenediamine. The surface tension measurements on branched alkylamino- compounds demonstrated that surface activity of R12-1.0G is superior to that of R12-0.5G at 25°C. It has been found that the self-assembly of R12-1.0G and lauric acid formed by electrostatic interaction and the self-assembly of the molecule might transfer water-soluble dyes from water to toluene. These AAC might be applied for treating dyes in wastewater. The mass ratio of lauric to toluene, the concentration of R12-1.0G, and hydrophilic groups of dyes affected the transfer rate of the water-soluble dyes. The transfer rates of the watersoluble dyes by R12-1.0G were higher than that of 1.0G polyacrylamide-acrylamide.

Effect of water on self-assembled tubules in β-sitosterol + γ-oryzanol-based organogels

NASA Astrophysics Data System (ADS)

den Adel, Ruud; Heussen, Patricia C. M.; Bot, Arjen

2010-10-01

Mixtures of β-sitosterol and γ-oryzanol form a network in triglyceride oil that may serve as an alternative to the network of small crystallites of triglycerides occurring in regular oil structuring. The present x-ray diffraction study investigates the relation between the crystal forms of the individual compounds and the mixture in oil, water and emulsion. β-Sitosterol and γ-oryzanol form normal crystals in oil, in water, or in emulsions. The crystals are sensitive to the presence of water. The mixture of β-sitosterol + γ-oryzanol forms crystals in water and emulsions that can be traced back to the crystals of the pure compounds. Only in oil, a completely different structure emerges in the mixture of β-sitosterol + γ-oryzanol, which bears no relation to the structures that are formed by both individual compounds, and which can be identified as a self-assembled tubule (diameter 7.2±0.1 nm, wall thickness 0.8±0.2 nm).

Broad spectrum antibiotic compounds and use thereof

DOEpatents

Koglin, Alexander; Strieker, Matthias

2016-07-05

The discovery of a non-ribosomal peptide synthetase (NRPS) gene cluster in the genome of Clostridium thermocellum that produces a secondary metabolite that is assembled outside of the host membrane is described. Also described is the identification of homologous NRPS gene clusters from several additional microorganisms. The secondary metabolites produced by the NRPS gene clusters exhibit broad spectrum antibiotic activity. Thus, antibiotic compounds produced by the NRPS gene clusters, and analogs thereof, their use for inhibiting bacterial growth, and methods of making the antibiotic compounds are described.

Photochemical Formation of Sulfur-Containing Aerosols

NASA Astrophysics Data System (ADS)

Kroll, Jay A.; Vaida, Veronica

2017-06-01

In order to understand planetary climate systems, modeling the properties of atmospheric aerosols is vital. Aerosol formation plays an important role in planetary climates and is tied to feedback loops that can either warm or cool a planet. Sulfur compounds are known to play an important role in new particle aerosol formation and have been observed in a number of planetary atmospheres throughout our solar system. Our current understanding of sulfur chemistry explains much of what we observe in Earth's atmosphere; however, several discrepancies arise when comparing observations of the Venusian atmosphere with model predictions. This suggests that there are still problems in our fundamental understanding of sulfur chemistry. This is concerning given recent renewed interest in sulfate injections in the stratosphere for solar radiation management geo-engineering schemes. We investigate the role of sunlight as a potential driver of the formation of sulfur-containing aerosols. I will present recent work investigating the generation of large quantities of aerosol from the irradiation of mixtures of SO_2 with water and organic species, using a solar simulator that mimics the light that is available in the Earth's troposphere and the Venusian middle atmosphere. I will present on recent work done in our lab suggesting the formation of sulfurous acid, H_2SO_3, and describe experimental work that supports this proposed mechanism. Additionally I will present on new work showing the highly reactive nature of electronically excited SO_2 with saturated alkane species. The implications of this photochemically induced sulfur aerosol formation in the atmosphere of Earth and other planetary atmospheres will be discussed.

In Situ Biological Contamination Studies of the Moon: Implications for Planetary Protection and Life Detection Missions

NASA Technical Reports Server (NTRS)

Glavin, Daniel P.; Dworkin, Jason P.; Lupisella, Mark; Williams, David R.; Kminek, Gerhard; Rummel, John D.

2010-01-01

NASA and ESA have outlined visions for solar system exploration that will include a series of lunar robotic precursor missions to prepare for, and support a human return to the Moan, and future human exploration of Mars and other destinations, including possibly asteroids. One of the guiding principles for exploration is to pursue compelling scientific questions about the origin and evolution of life. The search for life on objects such as Mars will require careful operations, and that all systems be sufficiently cleaned and sterilized prior to launch to ensure that the scientific integrity of extraterrestrial samples is not jeopardized by terrestrial organic contamination. Under the Committee on Space Research's (COSPAR's) current planetary protection policy for the Moon, no sterilization procedures are required for outbound lunar spacecraft, nor is there a different planetary protection category for human missions, although preliminary C SPAR policy guidelines for human missions to Mars have been developed. Future in situ investigations of a variety of locations on the Moon by highly sensitive instruments designed to search for biologically derived organic compounds would help assess the contamination of the Moon by lunar spacecraft. These studies could also provide valuable "ground truth" data for Mars sample return missions and help define planetary protection requirements for future Mars bound spacecraft carrying life detection experiments. In addition, studies of the impact of terrestrial contamination of the lunar surface by the Apollo astronauts could provide valuable data to help refine future: Mars surface exploration plans for a human mission to Mars.

Measuring Enthalpy of Sublimation of Volatiles by Means of Piezoelectric Crystal Microbalances

NASA Astrophysics Data System (ADS)

Dirri, Fabrizio; Palomba, Ernesto; Longobardo, Andrea; Zampetti, Emiliano

2017-12-01

Piezoelectric Crystal Microbalances (PCM's) are widely used to study the chemical processes involving volatile compounds in any environment, such as condensation process. Since PCM's are miniaturized sensor, they are very suitable for planetary in situ missions, where can be used to detect and to measure the mass amount of astrobiologically significant compounds, such as water and organics. This work focuses on the realization and testing of a new experimental setup, able to characterize volatiles which can be found in a planetary environment. In particular the enthalpy of sublimation of some dicarboxylic acids has been measured. The importance of dicarboxylic acids in planetology and astrobiology is due to the fact that they have been detected in carbonaceous chondritic material (e.g. Murchinson), among the most pristine material present in our Solar System. In this work, a sample of acid was heated in an effusion cell up to its sublimation. For a set of temperatures (from 30 °C to 75 °C), the deposition rate on the PCM surface has been measured. From these measurements, it has been possible to infer the enthalpy of sublimation of Adipic acid, i.e. ΔH = 141.6 ± 0.8 kJ/mol and Succinic acid, i.e. ΔH = 113.3 ± 1.3 kJ/mol. This technique has so demonstrated to be a good choice to recognise a single compound or a mixture (with an analysis upstream) even if some improvements concerning the thermal stabilization of the system will be implemented in order to enhance the results' accuracy. The experiment has been performed in support of the VISTA (Volatile In Situ Thermogravimetry Analyzer) project, which is included in the scientific payload of the ESA MarcoPolo-R mission study.

Organic Synthesis via Irradiation and Warming of Ice Grains in the Solar Nebula

NASA Technical Reports Server (NTRS)

Ciesla, Fred J.; Sanford, Scott A.

2012-01-01

Complex organic compounds, including many important to life on Earth, are commonly found in meteoritic and cometary samples, though their origins remain a mystery. We examined whether such molecules could be produced within the solar nebula by tracking the dynamical evolution of ice grains in the nebula and recording the environments they were exposed to. We found that icy grains originating in the outer disk, where temperatures were less than 30 K, experienced UV irradiation exposures and thermal warming similar to that which has been shown to produce complex organics in laboratory experiments. These results imply that organic compounds are natural byproducts of protoplanetary disk evolution and should be important ingredients in the formation of all planetary systems, including our own.

Spin-canting magnetization in an unusual Co4 cluster-based layer compound from a 2,3-dihydroxyquinoxaline ligand.

PubMed

Yang, Chen-I; Chuang, Po-Hsiang; Lee, Gene-Hsiang; Peng, Shie-Ming; Lu, Kuang-Lieh

2012-01-16

The self-assembly of Co(O(2)CPh)(2) with a 2,3-dihydroxyquinoxaline (H(2)dhq) linker has revealed a new two-dimensional cluster-based compound, [Co(4)(OMe)(2)(O(2)CPh)(2)(dhq)(2)(MeOH)(2)](n), which shows spin-canted magnetization and a definite magnetic hysteresis loop.

Mechanical design of a shape memory alloy actuated prosthetic hand.

PubMed

De Laurentis, Kathryn J; Mavroidis, Constantinos

2002-01-01

This paper presents the mechanical design for a new five fingered, twenty degree-of-freedom dexterous hand patterned after human anatomy and actuated by Shape Memory Alloy artificial muscles. Two experimental prototypes of a finger, one fabricated by traditional means and another fabricated by rapid prototyping techniques, are described and used to evaluate the design. An important aspect of the Rapid Prototype technique used here is that this multi-articulated hand will be fabricated in one step, without requiring assembly, while maintaining its desired mobility. The use of Shape Memory Alloy actuators combined with the rapid fabrication of the non-assembly type hand, reduce considerably its weight and fabrication time. Therefore, the focus of this paper is the mechanical design of a dexterous hand that combines Rapid Prototype techniques and smart actuators. The type of robotic hand described in this paper can be utilized for applications requiring low weight, compactness, and dexterity such as prosthetic devices, space and planetary exploration.

Research and Development of External Occultor Technology for the Direct Observation of Extrasolar Planetary Systems : JPL Starshades Project

NASA Technical Reports Server (NTRS)

Franz, Herbert; Stadeler, Mehnert

2012-01-01

Our group conducted work during the Summer of 2012 assembling and developing JPL's Starshades Project under the Technology Development for Exoplanet Missions(TDEM) initiative created by NASA, specifically TDEM stage 2. The goal of the work conducted at JPL by our group was to construct four occultor petals, the main optical components of the Starshade, for the analysis of joint deployment characteristics and of mechanical strain. A Starshade is an optical structure measuring approximately 30 meters in diameter that uses the effects of light diffraction off sheer edges, light scattering, and negative interference between waves to negate all on-axis light in a telescope's image, providing very high contrast that allows planets orbiting a target star to be observed. We completed our engineering goals in the time span of 10 weeks, during which the assembly processes of manufacture, alignment, and structural bonding took place. The Starshade technology and construction process is further discussed in the body of this paper.

Controlling Corrosion in Defence Equipment - Technical Meeting,

DTIC Science & Technology

1985-10-01

methods identify elements. (c) IR absorption spectroscopy. % e The identifies radicals, sometimes compounds. X-ray fluorescence and atomic absorption ...components from this radio. There were 100 sets all with defective - silver plating, with a total value of $5 million. A method of refurbishment was...Assemblies from the FiiC Aircraft Slides of a corroded heat exchanger assembly were shown. A method of refurbishment was suggested. Estimated saving - $0.5

Non-planetary Science from Planetary Missions

NASA Astrophysics Data System (ADS)

Elvis, M.; Rabe, K.; Daniels, K.

2015-12-01

Planetary science is naturally focussed on the issues of the origin and history of solar systems, especially our own. The implications of an early turbulent history of our solar system reach into many areas including the origin of Earth's oceans, of ores in the Earth's crust and possibly the seeding of life. There are however other areas of science that stand to be developed greatly by planetary missions, primarily to small solar system bodies. The physics of granular materials has been well-studied in Earth's gravity, but lacks a general theory. Because of the compacting effects of gravity, some experiments desired for testing these theories remain impossible on Earth. Studying the behavior of a micro-gravity rubble pile -- such as many asteroids are believed to be -- could provide a new route towards exploring general principles of granular physics. These same studies would also prove valuable for planning missions to sample these same bodies, as techniques for anchoring and deep sampling are difficult to plan in the absence of such knowledge. In materials physics, first-principles total-energy calculations for compounds of a given stoichiometry have identified metastable, or even stable, structures distinct from known structures obtained by synthesis under laboratory conditions. The conditions in the proto-planetary nebula, in the slowly cooling cores of planetesimals, and in the high speed collisions of planetesimals and their derivatives, are all conditions that cannot be achieved in the laboratory. Large samples from comets and asteroids offer the chance to find crystals with these as-yet unobserved structures as well as more exotic materials. Some of these could have unusual properties important for materials science. Meteorites give us a glimpse of these exotic materials, several dozen of which are known that are unique to meteorites. But samples retrieved directly from small bodies in space will not have been affected by atmospheric entry, warmth or weathering. We give examples from both of these fields of enquiry.

Self-assembly processes in the prebiotic environment

PubMed Central

Deamer, David; Singaram, Sara; Rajamani, Sudha; Kompanichenko, Vladimir; Guggenheim, Stephen

2006-01-01

An important question guiding research on the origin of life concerns the environmental conditions where molecular systems with the properties of life first appeared on the early Earth. An appropriate site would require liquid water, a source of organic compounds, a source of energy to drive polymerization reactions and a process by which the compounds were sufficiently concentrated to undergo physical and chemical interactions. One such site is a geothermal setting, in which organic compounds interact with mineral surfaces to promote self-assembly and polymerization reactions. Here, we report an initial study of two geothermal sites where mixtures of representative organic solutes (amino acids, nucleobases, a fatty acid and glycerol) and phosphate were mixed with high-temperature water in clay-lined pools. Most of the added organics and phosphate were removed from solution with half-times measured in minutes to a few hours. Analysis of the clay, primarily smectite and kaolin, showed that the organics were adsorbed to the mineral surfaces at the acidic pH of the pools, but could subsequently be released in basic solutions. These results help to constrain the range of possible environments for the origin of life. A site conducive to self-assembly of organic solutes would be an aqueous environment relatively low in ionic solutes, at an intermediate temperature range and neutral pH ranges, in which cyclic concentration of the solutes can occur by transient dry intervals. PMID:17008220

Heteroaryldihydropyrimidine (HAP) and Sulfamoylbenzamide (SBA) Inhibit Hepatitis B Virus Replication by Different Molecular Mechanisms

PubMed Central

Zhou, Zheng; Hu, Taishan; Zhou, Xue; Wildum, Steffen; Garcia-Alcalde, Fernando; Xu, Zhiheng; Wu, Daitze; Mao, Yi; Tian, Xiaojun; Zhou, Yuan; Shen, Fang; Zhang, Zhisen; Tang, Guozhi; Najera, Isabel; Yang, Guang; Shen, Hong C.; Young, John A. T.; Qin, Ning

2017-01-01

Heteroaryldihydropyrimidine (HAP) and sulfamoylbenzamide (SBA) are promising non-nucleos(t)ide HBV replication inhibitors. HAPs are known to promote core protein mis-assembly, but the molecular mechanism of abnormal assembly is still elusive. Likewise, the assembly status of core protein induced by SBA remains unknown. Here we show that SBA, unlike HAP, does not promote core protein mis-assembly. Interestingly, two reference compounds HAP_R01 and SBA_R01 bind to the same pocket at the dimer-dimer interface in the crystal structures of core protein Y132A hexamer. The striking difference lies in a unique hydrophobic subpocket that is occupied by the thiazole group of HAP_R01, but is unperturbed by SBA_R01. Photoaffinity labeling confirms the HAP_R01 binding pose at the dimer-dimer interface on capsid and suggests a new mechanism of HAP-induced mis-assembly. Based on the common features in crystal structures we predict that T33 mutations generate similar susceptibility changes to both compounds. In contrast, mutations at positions in close contact with HAP-specific groups (P25A, P25S, or V124F) only reduce susceptibility to HAP_R01, but not to SBA_R01. Thus, HAP and SBA are likely to have distinctive resistance profiles. Notably, P25S and V124F substitutions exist in low-abundance quasispecies in treatment-naïve patients, suggesting potential clinical relevance. PMID:28205569

Photoswitching in azobenzene self-assembled monolayers capped on zinc oxide: nanodots vs nanorods.

PubMed

Shah, Syed Mujtaba; Martini, Cyril; Ackermann, Jörg; Fages, Frédéric

2012-02-01

We report the synthesis and spectroscopic characterization of nanohybrid structures consisting of an azobenzene compound grafted on the surface of zinc oxide nanoparticles. Characteristic bathochromic shifts indicate that the azobenzene photochromic molecules self-assemble onto the surface of the nanocrystals. The extent of packing is dependent on the shape of the nanoparticle. ZnO nanorods, with flat facets, enable a tighter organization of the molecules in the self-assembled monolayer than in the case of nanodots that display a more curvated shape. Consistently, the efficiency of photochromic switching of the self-assembled monolayer on ZnO nanoparticles is also shown to be strongly affected by nanoparticle shape. Copyright © 2011 Elsevier Inc. All rights reserved.

Using portable Raman spectrometers for the identification of organic compounds at low temperatures and high altitudes: exobiological applications.

PubMed

Jehlicka, J; Edwards, H G M; Culka, A

2010-07-13

Organic minerals, organic acids and NH-containing organic molecules represent important target molecules for astrobiology. Here, we present the results of the evaluation of a portable hand-held Raman spectrometer to detect these organic compounds outdoors under field conditions. These measurements were carried out during the February-March 2009 winter period in Austrian Alpine sites at temperatures ranging between -5 and -25 degrees C. The compounds investigated were detected under field conditions and their main Raman spectral features were observed unambiguously at their correct reference wavenumber positions. The results obtained demonstrate that a miniaturized Raman spectrometer equipped with 785 nm excitation could be applied with advantage as a key instrument for investigating the presence of organic minerals, organic acids and nitrogen-containing organic compounds outdoors under terrestrial low-temperature conditions. Within the payload designed by ESA and NASA for several missions focusing on Mars, Titan, Europa and other extraterrestrial bodies, Raman spectroscopy can be proposed as an important non-destructive analytical tool for the in situ identification of organic compounds relevant to life detection on planetary and moon surfaces or near subsurfaces.

Development of Additive Construction Technologies for Application to Development of Lunar/Martian Surface Structures Using In-Situ Materials

NASA Technical Reports Server (NTRS)

Werkheiser, Niki J.; Fiske, Michael R.; Edmunson, Jennifer E.; Khoshnevis, Berokh

2015-01-01

For long-duration missions on other planetary bodies, the use of in situ materials will become increasingly critical. As human presence on these bodies expands, so must the breadth of the structures required to accommodate them including habitats, laboratories, berms, radiation shielding for natural radiation and surface reactors, garages, solar storm shelters, greenhouses, etc. Planetary surface structure manufacturing and assembly technologies that incorporate in situ resources provide options for autonomous, affordable, pre-positioned environments with radiation shielding features and protection from micrometeorites, exhaust plume debris, and other hazards. The ability to use in-situ materials to construct these structures will provide a benefit in the reduction of up-mass that would otherwise make long-term Moon or Mars structures cost prohibitive. The ability to fabricate structures in situ brings with it the ability to repair these structures, which allows for the self-sufficiency and sustainability necessary for long-duration habitation. Previously, under the auspices of the MSFC In-Situ Fabrication and Repair (ISFR) project and more recently, under the jointly-managed MSFC/KSC Additive Construction with Mobile Emplacement (ACME) project, the MSFC Surface Structures Group has been developing materials and construction technologies to support future planetary habitats with in-situ resources. One such additive construction technology is known as Contour Crafting. This paper presents the results to date of these efforts, including development of novel nozzle concepts for advanced layer deposition using this process. Conceived initially for rapid development of cementitious structures on Earth, it also lends itself exceptionally well to the automated fabrication of planetary surface structures using minimally processed regolith as aggregate, and binders developed from in situ materials as well. This process has been used successfully in the fabrication of construction elements using lunar regolith simulant and Mars regolith simulant, both with various binder materials. Future planned activities will be discussed as well.

Multimodular biocatalysts for natural product assembly

NASA Astrophysics Data System (ADS)

Schwarzer, Dirk; Marahiel, Mohamed A.

2001-03-01

Nonribosomal peptides and polyketides represent a large class of natural products that show an extreme structural diversity and broad pharmacological relevance. They are synthesized from simple building blocks such as amino or carboxy acids and malonate derivatives on multimodular enzymes called nonribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs), respectively. Although utilizing different substrates, NRPSs and PKSs show striking similarities in the modular architecture of their catalytic domains and product assembly-line mechanism. Among these compounds are well known antibiotics (penicillin, vancomycin and erythromycin) as well as potent immunosuppressive agents (cyclosporin, rapamycin and FK 506). This review focuses on the modular organization of NRPSs, PKSs and mixed NRPS/PKS systems and how modules and domains that build up the biosynthetic templates can be exploited for the rational design of recombinant enzymes capable of synthesizing novel compounds.

Redox-promoted associative assembly of metal–organic materials† †Electronic supplementary information (ESI) available: Experimental procedures, compound characterization data, and X-ray crystallographic data for compounds 3–7 and 9–11. CCDC 1405641–1405645, 1429643, 1405647 and 1405648. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c5sc02214b Click here for additional data file. Click here for additional data file.

PubMed Central

Glavinović, Martin; Qi, Feng; Katsenis, Athanassios D.

2016-01-01

We develop an associative synthesis of metal–organic materials that combines solid-state metal oxidation and coordination-driven self-assembly into a one-step, waste-free transformation. The methodology hinges on the unique reactivity of ortho-quinones, which we introduce as versatile oxidants for mechanochemical synthesis. Our strategy opens a previously unexplored route to paramagnetic metal–organic materials from elementary metals. PMID:28791114

UV Astronomy: Stars from Birth to Death

NASA Astrophysics Data System (ADS)

Gómez de Castro, Ana I.; Barstow, Martin A.

The Joint Discussion on UV Astronmy: Stars from Birth to Death was held during the IAU General Assembly of 2006, in August 2006. It was aimed to provide a forum where the accomplishments of UV astrophysics could be highlighted and a new roadmap for the future discussed. This meeting focussed in particular on stellar astrophysics. The understanding of stellar physics is at the very base of our understanding of the Universe. The chemical evolution of the Universe is controlled by stars. Supernovae are prime distance indicators that have allowed to measure the evolution of the curvature of the Universe and to detect the existence of dark energy. The development of life sustaining system depends strongly on the evolution of stars like our Sun. Some of the most extreme forms of matter in the Universe, the densest and more strongly magnetized, are the magnetars, debris of stellar evolution. The excellent contributions presented in this Joint Discussion dealt with the many aspects of stellar astrophysics from the analysis of dissipative processes in the atmosphere of cool stars and their impact on the evolution of the planetary systems to the study of the atmospheres and winds of the hot massive stars or the determination of the abundances in white dwarfs. The physics of disks, its role in the evolution of binary systems, and the formation of supernovae were among the main topics treated in the meeting. We should also not forget the role of starbursts and, in general, high mass stars in the chemical evolution of galaxies. The metallicity gradient in the Galaxy is traced in the UV spectrum of planetary nebulae. The evolution of young planetary disks and the role of the central stars in the photoevaporation of the giant gaseous planets that have been detected recently. The book contains a summary of the numerous and high quality contributions to this Joint Discussion classified in five chapters: * Chapter 1: Star Formation and Young Stellar Objects * Chapter 2: Life in Main Sequence * Chapter 3: Star Death * Chapter 4: Compact Objects * Chapter 5: The impact of stellar astrophysics in understanding the formation of life sustainable systems; That correspond to the five sessions held during the meeting. A summary of the current status of UV astronomy and the discussions that took place during the XXVIth I. A. U. General Assembly can be found in Highlights of Astronomy, Volume 14.

SOS System Induction Inhibits the Assembly of Chemoreceptor Signaling Clusters in Salmonella enterica

PubMed Central

Irazoki, Oihane; Mayola, Albert; Campoy, Susana; Barbé, Jordi

2016-01-01

Swarming, a flagellar-driven multicellular form of motility, is associated with bacterial virulence and increased antibiotic resistance. In this work we demonstrate that activation of the SOS response reversibly inhibits swarming motility by preventing the assembly of chemoreceptor-signaling polar arrays. We also show that an increase in the concentration of the RecA protein, generated by SOS system activation, rather than another function of this genetic network impairs chemoreceptor polar cluster formation. Our data provide evidence that the molecular balance between RecA and CheW proteins is crucial to allow polar cluster formation in Salmonella enterica cells. Thus, activation of the SOS response by the presence of a DNA-injuring compound increases the RecA concentration, thereby disturbing the equilibrium between RecA and CheW and resulting in the cessation of swarming. Nevertheless, when the DNA-damage decreases and the SOS response is no longer activated, basal RecA levels and thus polar cluster assembly are reestablished. These results clearly show that bacterial populations moving over surfaces make use of specific mechanisms to avoid contact with DNA-damaging compounds. PMID:26784887

SOS System Induction Inhibits the Assembly of Chemoreceptor Signaling Clusters in Salmonella enterica.

PubMed

Irazoki, Oihane; Mayola, Albert; Campoy, Susana; Barbé, Jordi

2016-01-01

Swarming, a flagellar-driven multicellular form of motility, is associated with bacterial virulence and increased antibiotic resistance. In this work we demonstrate that activation of the SOS response reversibly inhibits swarming motility by preventing the assembly of chemoreceptor-signaling polar arrays. We also show that an increase in the concentration of the RecA protein, generated by SOS system activation, rather than another function of this genetic network impairs chemoreceptor polar cluster formation. Our data provide evidence that the molecular balance between RecA and CheW proteins is crucial to allow polar cluster formation in Salmonella enterica cells. Thus, activation of the SOS response by the presence of a DNA-injuring compound increases the RecA concentration, thereby disturbing the equilibrium between RecA and CheW and resulting in the cessation of swarming. Nevertheless, when the DNA-damage decreases and the SOS response is no longer activated, basal RecA levels and thus polar cluster assembly are reestablished. These results clearly show that bacterial populations moving over surfaces make use of specific mechanisms to avoid contact with DNA-damaging compounds.

Pathways Towards Habitable Planets: Capabilities of the James Webb Space Telescope

NASA Technical Reports Server (NTRS)

Clampin, Mark

2009-01-01

The James Webb Space Telescope (JWST) is a large aperture (6.5 meter), cryogenic space telescope with a suite of near and mid-infrared instruments covering the wavelength range of 0.6 m to 28 m. JWST s primary science goal is to detect and characterize the first galaxies. It will also study the assembly of galaxies, star formation, and the formation of evolution of planetary systems. We also review the expected scientific performance of the observatory for observations of exosolar planets by means of transit photometry and spectroscopy, and direct coronagraphic imaging and address its role in the search for habitable planets.

Planetary geological studies. [MARS crater morphology and ejecta deposit topography

NASA Technical Reports Server (NTRS)

Blasius, K. R.

1981-01-01

A global data base was assembled for the study of Mars crater ejecta morphology. The craters were classified as to morhology using individual photographic prints of Viking orbiter frames. Positional and scale information were derived by fitting digitized mosaic coordinates to lattitude-longitude coordinates of surface features from the Mars geodetic control net and feature coordinates from the U.S.G.S. series of 1:5,00,000 scale shaded relief maps. Crater morphology characteristics recorded are of two classes - attributes of each ejecta deposit and other crater charactersitics. Preliminary efforts to check the data base with findings of other workers are described.

A Survey of Space Robotics

NASA Technical Reports Server (NTRS)

Pedersen, L.; Kortenkamp, D.; Wettergreen, D.; Nourbakhsh, I.; Korsmeyer, David (Technical Monitor)

2003-01-01

In this paper we summarize a survey conducted by NASA to determine the state-of-the-art in space robotics and to predict future robotic capabilities under either nominal and intensive development effort. The space robotics assessment study examined both in-space operations including assembly, inspection, and maintenance and planetary surface operations like mobility and exploration. Applications of robotic autonomy and human-robot cooperation were considered. The study group devised a decomposition of robotic capabilities and then suggested metrics to specify the technical challenges associated with each. The conclusion of this paper identifies possible areas in which investment in space robotics could lead to significant advances of important technologies.

The James Webb Space Telescope

NASA Technical Reports Server (NTRS)

Mather, John C.

2003-01-01

The James Webb Space Telescope (JWST) will extend the discoveries of the Hubble Space Telescope by deploying a large cooled infrared telescope at the Sun-Earth Lagrange point L2. With a 6 m aperture and three instruments covering the wavelength range from 0.6 to 28 pm, it will provide sensitivities orders of magnitude better than any other facilities. It is intended to observe the light from the first galaxies and the first supernovae, the assembly of galaxies, and the formation and evolution of stars and planetary systems. In this talk I will review the scientific objectives, the hardware concepts and technology, and the predicted system performance.

The James Webb Space Telscope

NASA Technical Reports Server (NTRS)

Mather, John C.

2003-01-01

The James Webb Space Telescope (JWST) will extend the discoveries of the Hubble Space Telescope by deploying a large cooled infrared telescope at the Sun-Earth Lagrange point L2. With a 6 m aperture and three instruments covering the wavelength range from 0.6 to 28 microns, it will provide sensitivities orders of magnitude better than any other facilities. It is intended to observe the light from the first galaxies and the first supernovae, the assembly of galaxies, and the formation and evolution of stars and planetary systems. In this talk I will review the scientific objectives, the hardware concepts and technology, and the predicted system performance.

RNA-Seq analysis and annotation of a draft blueberry genome assembly identifies candidate genes involved in fruit ripening, biosynthesis of bioactive compounds, and stage-specific alternative splicing.

PubMed

Gupta, Vikas; Estrada, April D; Blakley, Ivory; Reid, Rob; Patel, Ketan; Meyer, Mason D; Andersen, Stig Uggerhøj; Brown, Allan F; Lila, Mary Ann; Loraine, Ann E

2015-01-01

Blueberries are a rich source of antioxidants and other beneficial compounds that can protect against disease. Identifying genes involved in synthesis of bioactive compounds could enable the breeding of berry varieties with enhanced health benefits. Toward this end, we annotated a previously sequenced draft blueberry genome assembly using RNA-Seq data from five stages of berry fruit development and ripening. Genome-guided assembly of RNA-Seq read alignments combined with output from ab initio gene finders produced around 60,000 gene models, of which more than half were similar to proteins from other species, typically the grape Vitis vinifera. Comparison of gene models to the PlantCyc database of metabolic pathway enzymes identified candidate genes involved in synthesis of bioactive compounds, including bixin, an apocarotenoid with potential disease-fighting properties, and defense-related cyanogenic glycosides, which are toxic. Cyanogenic glycoside (CG) biosynthetic enzymes were highly expressed in green fruit, and a candidate CG detoxification enzyme was up-regulated during fruit ripening. Candidate genes for ethylene, anthocyanin, and 400 other biosynthetic pathways were also identified. Homology-based annotation using Blast2GO and InterPro assigned Gene Ontology terms to around 15,000 genes. RNA-Seq expression profiling showed that blueberry growth, maturation, and ripening involve dynamic gene expression changes, including coordinated up- and down-regulation of metabolic pathway enzymes and transcriptional regulators. Analysis of RNA-seq alignments identified developmentally regulated alternative splicing, promoter use, and 3' end formation. We report genome sequence, gene models, functional annotations, and RNA-Seq expression data that provide an important new resource enabling high throughput studies in blueberry.

Draft Genome Sequence of Bioactive-Compound-Producing Cyanobacterium Tolypothrix campylonemoides Strain VB511288

PubMed Central

Das, Subhadeep; Singh, Deeksha; Madduluri, Madhavi; Chandrababunaidu, Mathu Malar; Gupta, Akash

2015-01-01

We report here the draft genome sequence of Tolypothrix campylonemoides VB511288, isolated from building facades in Santiniketan, India. The members of this genus produce several compounds of commercial importance. The draft assembly is 10,627,177 bases in 135 scaffolds, and it contains 7,886 protein-coding genes, 994 pseudogenes, 18 rRNA genes, and 76 tRNA genes. PMID:25838485

Synthesis of structurally diverse benzosuberene analogues and their biological evaluation as anti-cancer agents

PubMed Central

Tanpure, Rajendra P.; George, Clinton S.; Strecker, Tracy E.; Devkota, Laxman; Tidmore, Justin K.; Lin, Chen-Ming; Herdman, Christine A.; MacDonough, Matthew T.; Sriram, Madhavi; Chaplin, David J.; Trawick, Mary Lynn; Pinney, Kevin G.

2014-01-01

Diversely functionalized, fused aryl-alkyl ring systems hold a prominent position as well-established molecular frameworks for a variety of anti-cancer agents. The benzosuberene (6,7 fused, also referred to as dihydro-5H-benzo[7]annulene and benzocycloheptene) ring system has emerged as a valuable molecular core component for the development of inhibitors of tubulin assembly, which function as antiproliferative anti-cancer agents and, in certain cases, as vascular disrupting agents (VDAs). Both a phenolic-based analogue (known as KGP18, compound 39) and its corresponding amine-based congener (referred to as KGP156, compound 45), which demonstrate strong inhibition of tubulin assembly (low micromolar range) and potent cytotoxicity (picomolar range for KGP18 and nanomolar range for KGP156) are noteworthy examples of such benzosuberene-based compounds. In order to extend the structure-activity relationship (SAR) knowledge base related to benzosuberene anti-cancer agents, a series of eleven analogues (including KGP18) were prepared in which the methoxylation pattern on the pendant aryl ring as well as functional group incorporation on the fused aryl ring were varied. The synthetic approach to these compounds featured a sequential Wittig olefination, reduction, Eaton's reagent-mediated cyclization strategy to achieve the core benzosuberone intermediate, and represented a higher-yielding synthesis of KGP18 (which we prepared previously through a ring-expansion strategy). Incorporation of a fluorine or chlorine atom at the 1-position of the fused aryl ring or replacement of one of the methoxy groups with hydrogen (on the pendant aryl ring of KGP18) led to benzosuberene analogues that were both strongly inhibitory against tubulin assembly (IC50 approximately 1.0 M) and strongly cytotoxic against selected human cancer cell lines (for example, GI50 = 5.47 nM against NCI-H460 cells with fluorobenzosuberene analogue 37). A water-soluble phosphate prodrug salt of KGP18 (referred to as KGP265, compound 44) and a water-soluble serinamide salt (compound 48) of KGP156 were also synthesized and evaluated in this study. PMID:24183586

Diversity of anaerobic microbes in spacecraft assembly clean rooms.

PubMed

Probst, Alexander; Vaishampayan, Parag; Osman, Shariff; Moissl-Eichinger, Christine; Andersen, Gary L; Venkateswaran, Kasthuri

2010-05-01

Although the cultivable and noncultivable microbial diversity of spacecraft assembly clean rooms has been previously documented using conventional and state-of-the-art molecular techniques, the occurrence of obligate anaerobes within these clean rooms is still uncertain. Therefore, anaerobic bacterial communities of three clean-room facilities were analyzed during assembly of the Mars Science Laboratory rover. Anaerobic bacteria were cultured on several media, and DNA was extracted from suitable anaerobic enrichments and examined with conventional 16S rRNA gene clone library, as well as high-density phylogenetic 16S rRNA gene microarray (PhyloChip) technologies. The culture-dependent analyses predominantly showed the presence of clostridial and propionibacterial strains. The 16S rRNA gene sequences retrieved from clone libraries revealed distinct microbial populations associated with each clean-room facility, clustered exclusively within gram-positive organisms. PhyloChip analysis detected a greater microbial diversity, spanning many phyla of bacteria, and provided a deeper insight into the microbial community structure of the clean-room facilities. This study presents an integrated approach for assessing the anaerobic microbial population within clean-room facilities, using both molecular and cultivation-based analyses. The results reveal that highly diverse anaerobic bacterial populations persist in the clean rooms even after the imposition of rigorous maintenance programs and will pose a challenge to planetary protection implementation activities.

Assembly-directed antivirals differentially bind quasiequivalent pockets to modify hepatitis B virus capsid tertiary and quaternary structure.

PubMed

Katen, Sarah P; Tan, Zhenning; Chirapu, Srinivas Reddy; Finn, M G; Zlotnick, Adam

2013-08-06

Hepatitis B virus (HBV) is a major cause of liver disease. Assembly of the HBV capsid is a critical step in virus production and an attractive target for new antiviral therapies. We determined the structure of HBV capsid in complex with AT-130, a member of the phenylpropenamide family of assembly effectors. AT-130 causes tertiary and quaternary structural changes but does not disrupt capsid structure. AT-130 binds a hydrophobic pocket that also accommodates the previously characterized heteroaryldihydropyrimidine compounds but favors a unique quasiequivalent location on the capsid surface. Thus, this pocket is a promiscuous drug-binding site and a likely target for different assembly effectors with a broad range of mechanisms of activity. That AT-130 successfully decreases virus production by increasing capsid assembly rate without disrupting capsid structure delineates a paradigm in antiviral design, that disrupting reaction timing is a viable strategy for assembly effectors of HBV and other viruses. Copyright © 2013 Elsevier Ltd. All rights reserved.

Publications of the exobiology program for 1990: A special bibliography

NASA Technical Reports Server (NTRS)

1992-01-01

The Exobiology Program is an integrated program designed to investigate and understand those processes related to the origin, evolution, and distribution of life in the universe. The Exobiology Program is broad in scope, covering the following subject areas: cosmic evolution of biogenic compounds; prebiotic evolution; early evolution of life; evolution of advanced life; solar system exploration; search for extraterrestrial intelligence; planetary protection; and advanced programs in biological systems research. A listing of the 1990 publications resulting from research supported by the Exobiology Program is presented.

Clean Assembly of Genesis Collector Canister for Flight: Lessons for Planetary Sample Return

NASA Technical Reports Server (NTRS)

Allton, J. H.; Stansbery, E. K.; Allen, C. C.; Warren, J. L.; Schwartz, C. M.

2007-01-01

Measurement of solar composition in the Genesis collectors requires not only high sensitivity but very low blanks; thus, very strict collector contamination minimization was required beginning with mission planning and continuing through hardware design, fabrication, assembly and testing. Genesis started with clean collectors and kept them clean inside of a canister. The mounting hardware and container for the clean collectors were designed to be cleanable, with access to all surfaces for cleaning. Major structural components were made of aluminum and cleaned with megasonically energized ultrapure water (UPW). The UPW purity was >18 M resistivity. Although aluminum is relatively difficult to clean, the Genesis protocol achieved level 25 and level 50 cleanliness on large structural parts; however, the experience suggests that surface treatments may be helpful on future missions. All cleaning was performed in an ISO Class 4 (Class 10) cleanroom immediately adjacent to an ISO Class 4 assembly room; thus, no plastic packaging was required for transport. Persons assembling the canister were totally enclosed in cleanroom suits with face shield and HEPA filter exhaust from suit. Interior canister materials, including fasteners, were installed, untouched by gloves, using tweezers and other stainless steel tools. Sealants/lubricants were not exposed inside the canister, but vented to the exterior and applied in extremely small amounts using special tools. The canister was closed in ISO Class 4, not to be opened until on station at Earth-Sun L1. Throughout the cleaning and assembly, coupons of reference materials that were cleaned at the same time as the flight hardware were archived for future reference and blanks. Likewise reference collectors were archived. Post-mission analysis of collectors has made use of these archived reference materials.

Albumin binds self-assembling dyes as specific polymolecular ligands.

PubMed

Stopa, Barbara; Rybarska, Janina; Drozd, Anna; Konieczny, Leszek; Król, Marcin; Lisowski, Marek; Piekarska, Barbara; Roterman, Irena; Spólnik, Paweł; Zemanek, Grzegorz

2006-12-15

Self-assembling dyes with a structure related to Congo red (e.g. Evans blue) form polymolecular complexes with albumin. The dyes, which are lacking a self-assembling property (Trypan blue, ANS) bind as single molecules. The supramolecular character of dye ligands bound to albumin was demonstrated by indicating the complexation of dye molecules outnumbering the binding sites in albumin and by measuring the hydrodynamic radius of albumin which is growing upon complexation of self-assembling dye in contrast to dyes lacking this property. The self-assembled character of Congo red was also proved using it as a carrier introducing to albumin the intercalated nonbonding foreign compounds. Supramolecular, ordered character of the dye in the complex with albumin was also revealed by finding that self-assembling dyes become chiral upon complexation. Congo red complexation makes albumin less resistant to low pH as concluded from the facilitated N-F transition, observed in studies based on the measurement of hydrodynamic radius. This particular interference with protein stability and the specific changes in digestion resulted from binding of Congo red suggest that the self-assembled dye penetrates the central crevice of albumin.

The James Webb Space Telescope

NASA Technical Reports Server (NTRS)

Gardner, Jonathan P.

2011-01-01

The James Webb Space Telescope is the scientific successor to the Hubble and Spitzer Space Telescopes, and is currently the largest scientific project under construction in the United States. It will be a large (6.6m) cold (50K) telescope launched into orbit around the second Earth-Sun Lagrange point. It is a partnership of NASA with the European and Canadian Space Agencies. Science with the James Webb Space Telescope falls into four themes. The End of the Dark Ages: First Light and Reionization theme seeks to identify the first luminous sources to form and to determine the ionization history of the universe. The Assembly of Galaxies theme seeks to determine how galaxies and the dark matter, gas, stars, metals, morphological structures, and black holes within them evolved from the epoch of reionization to the present. The Birth of Stars and Protoplanetary Systems theme seeks to unravel the birth and early evolution of stars, from infall onto dust-enshrouded protostars, to the genesis of planetary systems. The Planetary Systems and the Origins of Life theme seeks to determine the physical and chemical properties of planetary systems around nearby stars and of our own, and investigate the potential for life in those systems. Webb will have four instruments: The Near-Infrared Camera, the Near-Infrared multi-object Spectrograph, and the Tunable Filter Imager will cover the wavelength range 0.6 to 5 microns, while the Mid-Infrared Instrument will do both imaging and spectroscopy from 5 to 28.5 microns. I will conclude the talk with a description of recent technical progress in the construction of the observatory.

The James Webb Space Telescope

NASA Technical Reports Server (NTRS)

Gardner, Jonathan P.

2011-01-01

The James Webb Space Telescope is the scientific successor to the Hubble and Spitzer Space Telescopes, and is currently the largest scientific project under construction in the United States. It will be a large (6.6m) cold (50K) telescope launched in about 5 years into orbit around the second Earth-Sun Lagrange point. It is a partnership of NASA with the European and Canadian Space Agencies. Science with the James Webb Space Telescope falls into four themes. The End of the Dark Ages: First Light and Reionization theme seeks to identify the first luminous sources to form and to determine the ionization history of the universe. The Assembly of Galaxies theme seeks to determine how galaxies and the dark matter, gas, stars, metals, morphological structures, and black holes within them evolved from the epoch of reionization to the present. The Birth of Stars and Protoplanetary Systems theme seeks to unravel the birth and early evolution of stars, from infall onto dust-enshrouded protostars, to the genesis of planetary systems. The Planetary Systems and the Origins of Life theme seeks to determine the physical and chemical properties of planetary systems around nearby stars and of our own, and investigate the potential for life in those systems. Webb will have four instruments: The Near-Infrared Camera, the Near-Infrared multi-object Spectrograph, and the Tunable Filter Imager will cover the wavelength range 0.6 to 5 microns, while the Mid-Infrared Instrument will do both imaging and spectroscopy from 5 to 28.5 microns. I will conclude the talk with a description of recent technical progress in the construction of the observatory.

The James Webb Space Telescope

NASA Technical Reports Server (NTRS)

Gardner, Jonathan P.

2007-01-01

The scientific capabilities of the James Webb Space Telescope (JWST) fall into four themes. The End of the Dark Ages: First Light and Reionization theme seeks to identify the first luminous sources to form and to determine the ionization history of the universe. The Assembly of Galaxies theme seeks to determine how galaxies and the dark matter, gas, stars, metals, morphological structures, and active nuclei within them evolved from the epoch of reionization to the present. The Birth of Stars and Protoplanetary Systems theme seeks to unravel the birth and early evolution of stars, from infall onto dust-enshrouded protostars, to the genesis of planetary systems. The Planetary Systems and the Origins of Life theme seeks to determine the physical and chemical properties of planetary systems around nearby stars and of our own, and investigate the potential for life in those systems. To enable these four science themes, JWST will be a large (6.6m) cold (50K) telescope launched to the second Earth-Sun Lagrange point early in the next decade. It is the successor to the Hubble Space Telescope, and is a partnership of NASA, ESA and CSA. JWST will have four instruments: The Near-Infrared Camera, the Near-Infrared multi-object Spectrograph, and the Tunable Filter Imager will cover the wavelength range 0.6 to 5 microns, while the Mid-Infrared Instrument will do both imaging and spectroscopy from 5 to 28.5 microns. In this paper, the status and capabilities of the observatory and instruments in the context of the major scientific goals are reviewed.

Planetary Protection for future missions to Europa and other icy moons: the more things change...

NASA Astrophysics Data System (ADS)

Conley, C. A.; Race, M.

2007-12-01

NASA maintains a planetary protection policy regarding contamination of extraterrestrial bodies by terrestrial microorganisms and organic compounds, and sets limits intended to minimize or prevent contamination resulting from spaceflight missions. Europa continues to be a high priority target for astrobiological investigations, and other icy moons of the outer planets are becoming increasingly interesting as data are returned from current missions. In 2000, a study was released by the NRC that provided recommendations on preventing the forward contamination of Europa. This study addressed a number of issues, including cleaning and sterilization requirements, the applicability of protocols derived from Viking and other missions to Mars, and the need to supplement spore based culture methods in assessing spacecraft bioload. The committee also identified a number of future studies that would improve knowledge of Europa and better define issues related to forward contamination of that body. The standard recommended by the 2000 study and adopted by NASA uses a probabilistic approach, such that spacecraft sent to Europa must demonstrate a probability less than 10-4 per mission of contaminating an europan ocean with one viable terrestrial organism. A number of factors enter into the equation for calculating this probability, including at least bioload at launch, probability of survival during flight, probability of reaching the surface of Europa, and probability of reaching an europan ocean. Recently, the NASA Planetary Protection Subcommittee of the NASA Advisory Council has recommended that the probabilistic approach recommended for Europa be applied to all outer planet icy moons, until another NRC study can be convened to reevaluate the issues in light of recent data. This presentation will discuss the status of current and anticipated planetary protection considerations for missions to Europa and other icy moons.

Overview: Exobiology in solar system exploration

NASA Technical Reports Server (NTRS)

Carle, Glenn C.; Schwartz, Deborah E.

1992-01-01

In Aug. 1988, the NASA Ames Research Center held a three-day symposium in Sunnyvale, California, to discuss the subject of exobiology in the context of exploration of the solar system. Leading authorities in exobiology presented invited papers and assisted in setting future goals. The goals they set were as follows: (1) review relevant knowledge learned from planetary exploration programs; (2) detail some of the information that is yet to be obtained; (3) describe future missions and how exobiologists, as well as other scientists, can participate; and (4) recommend specific ways exobiology questions can be addressed on future exploration missions. These goals are in agreement with those of the Solar System Exploration Committee (SSEC) of the NASA Advisory Council. Formed in 1980 to respond to the planetary exploration strategies set forth by the Space Science Board of the National Academy of Sciences' Committee on Planetary and Lunar Exploration (COMPLEX), the SSEC's main function is to review the entire planetary program. The committee formulated a long-term plan (within a constrained budget) that would ensure a vital, exciting, and scientifically valuable effort through the turn of the century. The SSEC's goals include the following: determining the origin, evolution, and present state of the solar system; understanding Earth through comparative planetology studies; and revealing the relationship between the chemical and physical evolution of the solar system and the appearance of life. The SSEC's goals are consistent with the over-arching goal of NASA's Exobiology Program, which provides the critical framework and support for basic research. The research is divided into the following four elements: (1) cosmic evolution of the biogenic compounds; (2) prebiotic evolution; (3) origin and early evolution of life; and (4) evolution of advanced life.

Origin and evolution of planetary atmospheres

NASA Technical Reports Server (NTRS)

Lewis, John S.

1992-01-01

This report concerns several research tasks related to the origin and evolution of planetary atmospheres and the large-scale distribution of volatile elements in the Solar System. These tasks and their present status are as follows: (1) we have conducted an analysis of the volatility and condensation behavior of compounds of iron, aluminum, and phosphorus in the atmosphere of Venus in response to publish interpretations of the Soviet Venera probe XRF experiment data, to investigate the chemistry of volcanic gases, injection of volatiles by cometary and asteroidal impactors, and reactions in the troposphere; (2) we have completed and are now writing up our research on condensation-accretion modeling of the terrestrial planets; (3) we have laid the groundwork for a detailed study of the effects of water transport in the solar nebula on the bulk composition, oxidation state, and volatile content of preplanetary solids; (4) we have completed an extensive laboratory study of cryovolcanic materials in the outer solar system; (5) we have begun to study the impact erosion and shock alteration of the atmosphere of Mars resulting from cometary and asteroidal bombardment; and (6) we have developed a new Monte Carlo model of the cometary and asteroidal bombardment flux on the terrestrial planets, including all relevant chemical and physical processes associated with atmospheric entry and impact, to assess both the hazards posed by this bombardment to life on Earth and the degree of cross-correlation between the various phenomena (NO(x) production, explosive yield, crater production, iridium signature, etc.) that characterize this bombardment. The purpose of these investigations has been to contribute to the developing understanding of both the dynamics of long-term planetary atmosphere evolution and the short-term stability of planetary surface environments.

Venus: Halide cloud condensation and volatile element inventories

NASA Technical Reports Server (NTRS)

Lewis, J. S.; Fegley, B., Jr.

1982-01-01

Several Venus cloud condensates, including A12C16 as well as halides, oxides and sulfides of arsenic and antimony, are assessed for their thermodynamic and geochemical plausibility. Aluminum chloride can confidently be ruled out, and condensation of arsenic sulfides on the surface will cause arsenic compounds to be too rare to produce the observed clouds. Antimony may conceivably be sufficiently volatile, but the expected molecular form is gaseous SbS, not the chloride. Arsenic and antimony compounds in the atmosphere will be regulated at very low levels by sulfide precipitation, irrespective of the planetary inventory of As and Sb. Thus the arguments for a volatile-deficient origin for Venus based on the depletion of water and mercury (relative to Earth) cannot be tested by a search for atmospheric arsenic or antimony.

Organic synthesis via irradiation and warming of ice grains in the solar nebula.

PubMed

Ciesla, Fred J; Sandford, Scott A

2012-04-27

Complex organic compounds, including many important to life on Earth, are commonly found in meteoritic and cometary samples, though their origins remain a mystery. We examined whether such molecules could be produced within the solar nebula by tracking the dynamical evolution of ice grains in the nebula and recording the environments to which they were exposed. We found that icy grains originating in the outer disk, where temperatures were less than 30 kelvin, experienced ultraviolet irradiation exposures and thermal warming similar to that which has been shown to produce complex organics in laboratory experiments. These results imply that organic compounds are natural by-products of protoplanetary disk evolution and should be important ingredients in the formation of all planetary systems, including our own.

Optical analysis of a compound quasi-microscope for planetary landers

NASA Technical Reports Server (NTRS)

Wall, S. D.; Burcher, E. E.; Huck, F. O.

1974-01-01

A quasi-microscope concept, consisting of facsimile camera augmented with an auxiliary lens as a magnifier, was introduced and analyzed. The performance achievable with this concept was primarily limited by a trade-off between resolution and object field; this approach leads to a limiting resolution of 20 microns when used with the Viking lander camera (which has an angular resolution of 0.04 deg). An optical system is analyzed which includes a field lens between camera and auxiliary lens to overcome this limitation. It is found that this system, referred to as a compound quasi-microscope, can provide improved resolution (to about 2 microns ) and a larger object field. However, this improvement is at the expense of increased complexity, special camera design requirements, and tighter tolerances on the distances between optical components.

Raman Spectrometer for Surface Identification of Minerals and Organic Compounds on Silicate Planets and Small Solar-System Bodies

NASA Technical Reports Server (NTRS)

Haskin, Larry A.

2000-01-01

This summary is the final report of work on two-year grant. Our objectives for this project were (1) to demonstrate that Raman spectroscopy is an excellent method for determining mineralogy on the surface of the Moon, Mars, and other planetary bodies; (2) to construct a prototype of a small Raman spectrometer of the kind we suggest could be used on a lander or rover; and (3) to test the ability of that spectrometer to identify minerals and quantify mineral proportions in lunar materials and complex Martian analog materials, and to identify organic matter in planetary surface materials, all under roughly simulated field conditions. These goals have been met. The principal accomplishments of this PIDDP project have been the following: selection for flight; construction of a breadboard Raman probe; throughput confirmation of the breadboard Raman probe; selection of a laser; a breadboard spectrograph based on our PIDDP design; and overall result.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ozaki, N.; Nellis, W. J.; Mashimo, T.

Materials at high pressures and temperatures are of great current interest for warm dense matter physics, planetary sciences, and inertial fusion energy research. Shock-compression equation-of-state data and optical reflectivities of the fluid dense oxide, Gd 3Ga 5O 12 (GGG), were measured at extremely high pressures up to 2.6 TPa (26 Mbar) generated by high-power laser irradiation and magnetically-driven hypervelocity impacts. Above 0.75 TPa, the GGG Hugoniot data approach/reach a universal linear line of fluid metals, and the optical reflectivity most likely reaches a constant value indicating that GGG undergoes a crossover from fluid semiconductor to poor metal with minimum metallicmore » conductivity (MMC). These results suggest that most fluid compounds, e.g., strong planetary oxides, reach a common state on the universal Hugoniot of fluid metals (UHFM) with MMC at sufficiently extreme pressures and temperatures. Lastly, the systematic behaviors of warm dense fluid would be useful benchmarks for developing theoretical equation-of-state and transport models in the warm dense matter regime in determining computational predictions.« less

Honors

NASA Astrophysics Data System (ADS)

Anonymous

2012-05-01

A number of AGU members were honored during the European Geosciences Union's (EGU) General Assembly, held on 22-27 April in Vienna. EGU Union awards were presented to the following people: Vincent Courtillot, University of Paris Diderot, France, received the 2012 Arthur Holmes Medal and EGU honorary membership for seminal contributions to geomagnetism and the geodynamics of mantle hot spots.Michael Ghil, University of California, Los Angeles, and École Normale Supérieure, France, received the 2012 Alfred Wegener Medal and EGU honorary membership for his leading contributions to theoretical climate dynamics; his innovative observational studies involving model assimilation of satellite data in meteorology, oceanography, and space physics; the breadth of his interdisciplinary studies, including macroeconomics; and his extensive supervision and mentoring of scores of graduate and postdoctoral students. Robin Clarke, Universidade Federal do Rio Grande do Sul, Brazil, received the 2012 Alexander von Humboldt Medal for fundamental contributions in statistical analysis and modeling of hydrological processes.Angioletta Coradini, Istituto Nazionale di Astrofsica, Italy, received the 2012 Jean Dominique Cassini Medal and EGU honorary membership in recognition of her important and wide range of work in planetary sciences and solar system formation and for her leading role in the development of space infrared instrumentation for planetary exploration.

Next Generation Simulation Framework for Robotic and Human Space Missions

NASA Technical Reports Server (NTRS)

Cameron, Jonathan M.; Balaram, J.; Jain, Abhinandan; Kuo, Calvin; Lim, Christopher; Myint, Steven

2012-01-01

The Dartslab team at NASA's Jet Propulsion Laboratory (JPL) has a long history of developing physics-based simulations based on the Darts/Dshell simulation framework that have been used to simulate many planetary robotic missions, such as the Cassini spacecraft and the rovers that are currently driving on Mars. Recent collaboration efforts between the Dartslab team at JPL and the Mission Operations Directorate (MOD) at NASA Johnson Space Center (JSC) have led to significant enhancements to the Dartslab DSENDS (Dynamics Simulator for Entry, Descent and Surface landing) software framework. The new version of DSENDS is now being used for new planetary mission simulations at JPL. JSC is using DSENDS as the foundation for a suite of software known as COMPASS (Core Operations, Mission Planning, and Analysis Spacecraft Simulation) that is the basis for their new human space mission simulations and analysis. In this paper, we will describe the collaborative process with the JPL Dartslab and the JSC MOD team that resulted in the redesign and enhancement of the DSENDS software. We will outline the improvements in DSENDS that simplify creation of new high-fidelity robotic/spacecraft simulations. We will illustrate how DSENDS simulations are assembled and show results from several mission simulations.

Honors

NASA Astrophysics Data System (ADS)

2012-05-01

A number of AGU members were honored during the European Geosciences Union's (EGU) General Assembly, held on 22-27 April in Vienna. EGU Union awards were presented to the following people: Vincent Courtillot, University of Paris Diderot, France, received the 2012 Arthur Holmes Medal and EGU honorary membership for seminal contributions to geomagnetism and the geodynamics of mantle hot spots. Michael Ghil, University of California, Los Angeles, and École Normale Supérieure, France, received the 2012 Alfred Wegener Medal and EGU honorary membership for his leading contributions to theoretical climate dynamics; his innovative observational studies involving model assimilation of satellite data in meteorology, oceanography, and space physics; the breadth of his interdisciplinary studies, including macroeconomics; and his extensive supervision and mentoring of scores of graduate and postdoctoral students. Robin Clarke, Universidade Federal do Rio Grande do Sul, Brazil, received the 2012 Alexander von Humboldt Medal for fundamental contributions in statistical analysis and modeling of hydrological processes. Angioletta Coradini, Istituto Nazionale di Astrofsica, Italy, received the 2012 Jean Dominique Cassini Medal and EGU honorary membership in recognition of her important and wide range of work in planetary sciences and solar system formation and for her leading role in the development of space infrared instrumentation for planetary exploration.

Rapid Optimization of Engineered Metabolic Pathways with Serine Integrase Recombinational Assembly (SIRA).

PubMed

Merrick, C A; Wardrope, C; Paget, J E; Colloms, S D; Rosser, S J

2016-01-01

Metabolic pathway engineering in microbial hosts for heterologous biosynthesis of commodity compounds and fine chemicals offers a cheaper, greener, and more reliable method of production than does chemical synthesis. However, engineering metabolic pathways within a microbe is a complicated process: levels of gene expression, protein stability, enzyme activity, and metabolic flux must be balanced for high productivity without compromising host cell viability. A major rate-limiting step in engineering microbes for optimum biosynthesis of a target compound is DNA assembly, as current methods can be cumbersome and costly. Serine integrase recombinational assembly (SIRA) is a rapid DNA assembly method that utilizes serine integrases, and is particularly applicable to rapid optimization of engineered metabolic pathways. Using six pairs of orthogonal attP and attB sites with different central dinucleotide sequences that follow SIRA design principles, we have demonstrated that ΦC31 integrase can be used to (1) insert a single piece of DNA into a substrate plasmid; (2) assemble three, four, and five DNA parts encoding the enzymes for functional metabolic pathways in a one-pot reaction; (3) generate combinatorial libraries of metabolic pathway constructs with varied ribosome binding site strengths or gene orders in a one-pot reaction; and (4) replace and add DNA parts within a construct through targeted postassembly modification. We explain the mechanism of SIRA and the principles behind designing a SIRA reaction. We also provide protocols for making SIRA reaction components and practical methods for applying SIRA to rapid optimization of metabolic pathways. © 2016 Elsevier Inc. All rights reserved.

Detection and formation scenario of citric acid, pyruvic acid, and other possible metabolism precursors in carbonaceous meteorites

PubMed Central

Cooper, George; Reed, Chris; Nguyen, Dang; Carter, Malika; Wang, Yi

2011-01-01

Carbonaceous meteorites deliver a variety of organic compounds to Earth that may have played a role in the origin and/or evolution of biochemical pathways. Some apparently ancient and critical metabolic processes require several compounds, some of which are relatively labile such as keto acids. Therefore, a prebiotic setting for any such individual process would have required either a continuous distant source for the entire suite of intact precursor molecules and/or an energetic and compact local synthesis, particularly of the more fragile members. To date, compounds such as pyruvic acid, oxaloacetic acid, citric acid, isocitric acid, and α-ketoglutaric acid (all members of the citric acid cycle) have not been identified in extraterrestrial sources or, as a group, as part of a “one pot” suite of compounds synthesized under plausibly prebiotic conditions. We have identified these compounds and others in carbonaceous meteorites and/or as low temperature (laboratory) reaction products of pyruvic acid. In meteorites, we observe many as part of three newly reported classes of compounds: keto acids (pyruvic acid and homologs), hydroxy tricarboxylic acids (citric acid and homologs), and tricarboxylic acids. Laboratory syntheses using 13C-labeled reactants demonstrate that one compound alone, pyruvic acid, can produce several (nonenzymatic) members of the citric acid cycle including oxaloacetic acid. The isotopic composition of some of the meteoritic keto acids points to interstellar or presolar origins, indicating that such compounds might also exist in other planetary systems. PMID:21825143

Detection and formation scenario of citric acid, pyruvic acid, and other possible metabolism precursors in carbonaceous meteorites.

PubMed

Cooper, George; Reed, Chris; Nguyen, Dang; Carter, Malika; Wang, Yi

2011-08-23

Carbonaceous meteorites deliver a variety of organic compounds to Earth that may have played a role in the origin and/or evolution of biochemical pathways. Some apparently ancient and critical metabolic processes require several compounds, some of which are relatively labile such as keto acids. Therefore, a prebiotic setting for any such individual process would have required either a continuous distant source for the entire suite of intact precursor molecules and/or an energetic and compact local synthesis, particularly of the more fragile members. To date, compounds such as pyruvic acid, oxaloacetic acid, citric acid, isocitric acid, and α-ketoglutaric acid (all members of the citric acid cycle) have not been identified in extraterrestrial sources or, as a group, as part of a "one pot" suite of compounds synthesized under plausibly prebiotic conditions. We have identified these compounds and others in carbonaceous meteorites and/or as low temperature (laboratory) reaction products of pyruvic acid. In meteorites, we observe many as part of three newly reported classes of compounds: keto acids (pyruvic acid and homologs), hydroxy tricarboxylic acids (citric acid and homologs), and tricarboxylic acids. Laboratory syntheses using (13)C-labeled reactants demonstrate that one compound alone, pyruvic acid, can produce several (nonenzymatic) members of the citric acid cycle including oxaloacetic acid. The isotopic composition of some of the meteoritic keto acids points to interstellar or presolar origins, indicating that such compounds might also exist in other planetary systems.

In vitro and in vivo activity of LS 4477 and LS 4559, novel analogues of the tubulin binder estramustine.

PubMed

Nicholson, K M; Phillips, R M; Shnyder, S D; Bibby, M C

2002-01-01

LS 4477 and LS 4559, two of a series of N-acyl-aminoalkyl phenyl ethers, are rationally designed compounds based on the tubulin binder estramustine. This study investigated their mechanism of action and compared their effectiveness in relation to estramustine in vitro against a panel of human and murine cell lines and in vivo against two murine colon tumour models (MAC). At biologically relevant concentrations, LS 4477 and LS 4559 caused a 59.9 and 56% reduction in tubulin assembly, respectively, compared with a 28.4% reduction in tubulin assembly by estramustine. The analogues were approximately 100 times more potent in chemosensitivity tests in vitro than the parent compound. Both analogues were orally active against the MAC 15A murine tumour model, to a greater extent than estramustine, producing significant growth delays (P<0.01). Significant activity was also shown against the slower growing MAC 26 tumour for LS 4577 (the soluble pro-drug of LS 4559). The results presented in this study suggest these compounds warrant further development with a view to assessing their clinical activity.

Formation, transformation and superhydrophobicity of compound surfactant-assisted aligned ZnO nanoplatelets

NASA Astrophysics Data System (ADS)

Xue, Mingshan; Xu, Tao; Xie, Xiaolin; Ou, Junfei; Wang, Fajun; Li, Wen

2015-11-01

Synthesis and understanding of hierarchically nanostructured materials are significant for exploring peculiar functional properties and underlying applications. In this study, the self-assembly formation and detailed transformation process of ZnO nanoplatelets grown by hydrothermal methods with the addition of compound surfactants (CTAB and Tween-20) have been investigated. The initial growth of ZnO nanoplatelets as well as the subsequent formation of bilayer nanorod arrays and divergent nanocone arrays on the surface and side face of these nanoplatelets were found. Compared with the formation of bulk/block crystals without the case of surfactants, the addition of compound surfactants into zinc nitrate solution is responsible for the self-assembly processes of ZnO because of the effective role of CTAB in decreasing the degree of crystallinity and the positive effect of Tween-20 on decreasing the particle size owing to the space hindered effect. As-formed hierarchically micro-nanostructured ZnO exhibits superhydrophobicity without any chemical modification, which can make water droplets suspend on the air film trapped between the nanoplatelet and nanoplatelet as well as between nanocone and nanocone.

AstroBioLab: A Mobile Biotic and Soil Analysis Laboratory

NASA Technical Reports Server (NTRS)

Bada, J. L.; Zent, A. P.; Grunthaner, F. J.; Quinn, R. C.; Navarro-Gonzalex, R.; Gonez-Silva, B.; McKay, C. P.

2003-01-01

The Jet Propulsion Laboratory, Scripps Institution of Oceanography, and NASA Ames Research Center are currently developing a mobile Astrobiology Laboratory (AstroBioLab) for a series of field campaigns using the Chilean Atacama Desert as a Martian surface analog site. The Astrobiology Science and Technology for Exploring Planets (ASTEP) program funded AstroBioLab is designed around the Mars Organic Detector (MOD) instrument and the Mars Oxidant Instrument (MOI) which provide complementary data sets. Using this suite of Mars Instrument Development Program (MIDP) and Planetary Instrument Definition and Development Program (PIDDP) derived in situ instruments, which provide state-of-the-art organic compound detection (attomolar sensitivity) and depth profiling of oxidation chemistry, we measure and correlate the interplay of organic compounds, inorganic oxidants, UV irradiation and water abundance. This mobile laboratory studies the proposition that intense UV irradiation coupled with low levels of liquid water generates metastable oxidizing species that can consume moderate amounts of seeded organic compounds. Results from the initial spring 2003 field campaign will be presented.

Draft Genome Sequence of Bioactive-Compound-Producing Cyanobacterium Tolypothrix campylonemoides Strain VB511288.

PubMed

Das, Subhadeep; Singh, Deeksha; Madduluri, Madhavi; Chandrababunaidu, Mathu Malar; Gupta, Akash; Adhikary, Siba Prasad; Tripathy, Sucheta

2015-04-02

We report here the draft genome sequence of Tolypothrix campylonemoides VB511288, isolated from building facades in Santiniketan, India. The members of this genus produce several compounds of commercial importance. The draft assembly is 10,627,177 bases in 135 scaffolds, and it contains 7,886 protein-coding genes, 994 pseudogenes, 18 rRNA genes, and 76 tRNA genes. Copyright © 2015 Das et al.

Molecular biomimetics: nanotechnology through biology.

PubMed

Sarikaya, Mehmet; Tamerler, Candan; Jen, Alex K-Y; Schulten, Klaus; Baneyx, François

2003-09-01

Proteins, through their unique and specific interactions with other macromolecules and inorganics, control structures and functions of all biological hard and soft tissues in organisms. Molecular biomimetics is an emerging field in which hybrid technologies are developed by using the tools of molecular biology and nanotechnology. Taking lessons from biology, polypeptides can now be genetically engineered to specifically bind to selected inorganic compounds for applications in nano- and biotechnology. This review discusses combinatorial biological protocols, that is, bacterial cell surface and phage-display technologies, in the selection of short sequences that have affinity to (noble) metals, semiconducting oxides and other technological compounds. These genetically engineered proteins for inorganics (GEPIs) can be used in the assembly of functional nanostructures. Based on the three fundamental principles of molecular recognition, self-assembly and DNA manipulation, we highlight successful uses of GEPI in nanotechnology.

CuNi Nanoparticles Assembled on Graphene for Catalytic Methanolysis of Ammonia Borane and Hydrogenation of Nitro/Nitrile Compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Chao; Fu, Jiaju; Muzzio, Michelle

Here we report a solution phase synthesis of 16 nm CuNi nanoparticles (NPs) with the Cu/Ni composition control. These NPs are assembled on graphene (G) and show Cu/Ni composition-dependent catalysis for methanolysis of ammonia borane (AB) and hydrogenation of aromatic nitro (nitrile) compounds to primary amines in methanol at room temperature. Among five different CuNi NPs studied, the G-Cu 36Ni 64 NPs are the best catalyst for both AB methanolysis (TOF = 49.1 mol H2 mol CuNi -1 min -1 and E a = 24.4 kJ/mol) and hydrogenation reactions (conversion yield >97%). In conclusion, the G-CuNi represents a unique noble-metal-freemore » catalyst for hydrogenation reactions in a green environment without using pure hydrogen.« less

Detection of Volatile Organic Compounds by Self-assembled Monolayer Coated Sensor Array with Concentration-independent Fingerprints

PubMed Central

Chang, Ye; Tang, Ning; Qu, Hemi; Liu, Jing; Zhang, Daihua; Zhang, Hao; Pang, Wei; Duan, Xuexin

2016-01-01

In this paper, we have modeled and analyzed affinities and kinetics of volatile organic compounds (VOCs) adsorption (and desorption) on various surface chemical groups using multiple self-assembled monolayers (SAMs) functionalized film bulk acoustic resonator (FBAR) array. The high-frequency and micro-scale resonator provides improved sensitivity in the detections of VOCs at trace levels. With the study of affinities and kinetics, three concentration-independent intrinsic parameters (monolayer adsorption capacity, adsorption energy constant and desorption rate) of gas-surface interactions are obtained to contribute to a multi-parameter fingerprint library of VOC analytes. Effects of functional group’s properties on gas-surface interactions are also discussed. The proposed sensor array with concentration-independent fingerprint library shows potential as a portable electronic nose (e-nose) system for VOCs discrimination and gas-sensitive materials selections. PMID:27045012

Adaptive Correction from Virtually Complex Dynamic Libraries: The Role of Noncovalent Interactions in Structural Selection and Folding.

PubMed

Lafuente, Maria; Atcher, Joan; Solà, Jordi; Alfonso, Ignacio

2015-11-16

The hierarchical self-assembling of complex molecular systems is dictated by the chemical and structural information stored in their components. This information can be expressed through an adaptive process that determines the structurally fittest assembly under given environmental conditions. We have set up complex disulfide-based dynamic covalent libraries of chemically and topologically diverse pseudopeptidic compounds. We show how the reaction evolves from very complex mixtures at short reaction times to the almost exclusive formation of a major compound, through the establishment of intramolecular noncovalent interactions. Our experiments demonstrate that the systems evolve through error-check and error-correction processes. The nature of these interactions, the importance of the folding and the effects of the environment are also discussed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Failure Investigation & Design Optimization of a Photo-Multiplier Tube Assembly Under Thermal Loading

NASA Technical Reports Server (NTRS)

Dahya, Kevin

2004-01-01

Analysis of GLAST ACD Photo-Multiplier Tube (PMT) assembly under thermal loading demonstrates that the glass tube experiences high stresses due to Coefficient of Thermal Expansion mismatch, as well as increased stress due to high stiffness and incompressibility of potting compound. Further investigation shows adverse loading effects due to the magnetic shield, a thin piece of steel wrapped around the PMT. This steel, Mu Metal, contained an overlap region that directly attributed to crack propagation in the outside surface of the tube. Sensitivities to different configurations were studied to reduce the stress and provide a more uniform loading throughout the PMT to ensure mission success. Studies indicate substituting a softer and more compressible potting compound and moving the Mu metal from the glass tube to the outside wall of the aluminum housing yields lower stress.

CuNi Nanoparticles Assembled on Graphene for Catalytic Methanolysis of Ammonia Borane and Hydrogenation of Nitro/Nitrile Compounds

DOE PAGES

Yu, Chao; Fu, Jiaju; Muzzio, Michelle; ...

2017-01-12

Here we report a solution phase synthesis of 16 nm CuNi nanoparticles (NPs) with the Cu/Ni composition control. These NPs are assembled on graphene (G) and show Cu/Ni composition-dependent catalysis for methanolysis of ammonia borane (AB) and hydrogenation of aromatic nitro (nitrile) compounds to primary amines in methanol at room temperature. Among five different CuNi NPs studied, the G-Cu 36Ni 64 NPs are the best catalyst for both AB methanolysis (TOF = 49.1 mol H2 mol CuNi -1 min -1 and E a = 24.4 kJ/mol) and hydrogenation reactions (conversion yield >97%). In conclusion, the G-CuNi represents a unique noble-metal-freemore » catalyst for hydrogenation reactions in a green environment without using pure hydrogen.« less

Self-assembled monolayers from biphenyldithiol derivatives: optimization of the deprotection procedure and effect of the molecular conformation.

PubMed

Shaporenko, Andrey; Elbing, Mark; Błaszczyk, Alfred; von Hänisch, Carsten; Mayor, Marcel; Zharnikov, Michael

2006-03-09

A series of biphenyl-derived dithiol (BDDT) compounds with terminal acetyl-protected sulfur groups and different structural arrangements of both phenyl rings have been synthesized and fully characterized. The different arrangements were achieved by introducing hydrocarbon substituents in the 2 and 2' positions of the biphenyl backbone. The presented model compounds enable the investigation of the correlation between the intramolecular conformation and other physical properties of interest, like, e.g., molecular assembly or electronic transport properties. Here, the ability of these model compounds to form self-assembled monolayers (SAMs) on Au(111) and Ag(111) is investigated in details. The deprotection of the target molecules was performed in situ using either NH4OH or triethylamine (TEA) deprotection agent. The fabricated films were characterized by synchrotron-based high-resolution photoelectron spectroscopy and near-edge absorption fine structure spectroscopy. Whereas the deprotection by NH4OH was found to result in the formation of multilayer films, the deprotection by TEA allowed the preparation of densely packed BDDT SAMs with a noticeably higher orientational order and smaller molecular inclination on Ag than on Au. Introduction of the alkyl bridge between the individual rings of the biphenyl backbone did not lead to a noticeable change in the structure and packing density of the BDDT SAMs as long as the molecule had a planar conformation in the respective SAM. The deviation from this conformation resulted in the deterioration of the film quality and a decrease of the orientational order.

A discrete Cu cluster and a 3D MnII-CuII framework based on assembly of Mn2Cu4 clusters: synthesis, structure and magnetic properties.

PubMed

Chakraborty, Anindita; Escuer, Albert; Ribas, Joan; Maji, Tapas Kumar

2016-10-04

The synthesis, single-crystal structure characterization and detailed magnetic study of a homometallic hexanuclear Cu II cluster [Cu 6 (μ 3 -OH) 2 (ppk) 6 (H 2 O) 2 (NO 3 ) 4 ] (1) and a three-dimensional (3D) compound [{MnCu 2 (dpkO 2 H) 2 (dpkO 2 )N 3 }·(NO 3 )·H 2 O] n (2) (ppk = phenyl-2-pyridyl ketoxime; dpk = di-2-pyridyl ketone) consisting of heterometallic Mn II -Cu II hexanuclear cores as secondary building units are reported in this paper. In compound 1, two symmetry-related Cu 3 triangles consisting of a hydroxido-bridged trinuclear unit, [Cu 3 (μ 3 -OH)(ppk) 3 (H 2 O)(NO 3 )] + , are assembled through nitrate bridging giving rise to the homometallic Cu 6 cluster. Compound 2 contains heterometallic {MnCu} cores, which are further connected to each other through an azido bridging ligand in all the crystallographic directions, resulting in a 3D metal-organic framework. Construction of such a heterometallic 3D framework from {MnCu} units is until now, unknown. Magnetic studies of both 1 and 2 were performed in detail and both compounds show dominant antiferromagnetic interaction in the respective clusters. Compound 1 reveals significant spin frustration and anti-symmetric exchange interaction in the trinuclear cores, with a significantly high value of J av (-655 cm -1 ). Furthermore, compound 2 exhibits a dominant antiferromagnetic interaction, which is also supported by an extensive magneto-structural correlation which considers the different magnetic pathways.

An Explorer-Class Astrobiology Mission

NASA Technical Reports Server (NTRS)

Sandford, Scott; Greene, Thomas; Allamandola, Louis; Arno, Roger; Bregman, Jesse; Cox, Sylvia; Davis, Paul K.; Gonzales, Andrew; Haas, Michael; Hanel, Robert;

Planetary protection and Mars: requirements and constraints on the 2016 and 2018 missions, and beyond

NASA Astrophysics Data System (ADS)

Rummel, J.; Kminek, G.; Conley, C.

2011-10-01

The suite of missions being planned currently by NASA and ESA as a partnership under the name "ExoMars" include an orbiter and an entry, descent, and landing demonstrator module (EDM) for the 2016 "ExoMars Trace Gas Orbiter" mission (ExoMars TGO), as well as a highly capable rover to be launched in 2018 to address the original ExoMars objectives (including the Pasteur payload). This 2018 ExoMars rover is expected to begin a series of missions leading to the first sample return mission from Mars, also conducted jointly between NASA, ESA, and their partners (JMSR). Each of these missions and mission components has a role in enabling future Mars exploration, including the search for life or life-related compounds on Mars, and each of them has the potential to carry confounding biological and organic materials into sensitive environments on Mars. Accordingly, this suite of missions will be subjected to joint planetary protection requirements applied by both ESA and NASA to their respective components, according to the COSPAR-delineated planetary protection policy to protect Mars from contamination, and eventually to provide for the protection of the Earth from potential life returned in a martian sample. This paper will discuss the challenges ahead for mission designers and the mission science teams, and will outline some of the potential pitfalls involved with different mission options.

Two-Step Resonance-Enhanced Desorption Laser Mass Spectrometry for In Situ Analysis of Organic-Rich Environments

NASA Technical Reports Server (NTRS)

Getty, S. A.; Grubisic, A.; Uckert, K.; Li, X.; Cornish, T.; Cook, J. E.; Brinckerhoff, W. B.

2016-01-01

A wide diversity of planetary surfaces in the solar system represent high priority targets for in situ compositional and contextual analysis as part of future missions. The planned mission portfolio will inform our knowledge of the chemistry at play on Mars, icy moons, comets, and primitive asteroids, which can lead to advances in our understanding of the interplay between inorganic and organic building blocks that led to the evolution of habitable environments on Earth and beyond. In many of these environments, the presence of water or aqueously altered mineralogy is an important indicator of habitable environments that are present or may have been present in the past. As a result, the search for complex organic chemistry that may imply the presence of a feedstock, if not an inventory of biosignatures, is naturally aligned with targeted analyses of water-rich surface materials. Here we describe the two-step laser mass spectrometry (L2MS) analytical technique that has seen broad application in the study of organics in meteoritic samples, now demonstrated to be compatible with an in situ investigation with technique improvements to target high priority planetary environments as part of a future scientific payload. An ultraviolet (UV) pulsed laser is used in previous and current embodiments of laser desorption/ionization mass spectrometry (LDMS) to produce ionized species traceable to the mineral and organic composition of a planetary surface sample. L2MS, an advanced technique in laser mass spectrometry, is selective to the aromatic organic fraction of a complex sample, which can provide additional sensitivity and confidence in the detection of specific compound structures. Use of a compact two-step laser mass spectrometer prototype has been previously reported to provide specificity to key aromatic species, such as PAHs, nucleobases, and certain amino acids. Recent improvements in this technique have focused on the interaction between the mineral matrix and the organic analyte. The majority of planetary targets of astrobiological interest are characterized by the presence of water or hydrated mineral phases. Water signatures can indicate a history of available liquid water that may have played an important role in the chemical environment of these planetary surfaces and subsurfaces. The studies we report here investigate the influence of water content on the detectability of organics by L2MS in planetary analog samples.

Characterization and kinetics of surface functionalization and binding of biologically and chemically significant molecules

NASA Astrophysics Data System (ADS)

Steiner, Rachel

The purpose of this project is to investigate intermolecular interactions of organic molecular assemblies. By understanding the structure and physical interactions in these assemblies, we gain insights into practical applications for nanoscale systems built upon these surface structures. It is possible for organic chemists to create many forms of modified organic molecules, functionalizing them with specific reactive end groups. Through surface functionalization, enabling covalent or highly associative binding, it is possible to create ordered molecular assemblies of these molecules. Scientists can study the nature of this structure and the intermolecular interactions through spectroscopic, optical, and scattering experiments. To understand the self-assembly process in molecular systems, we preliminarily created monolayer films on silica substrates with a variety of organic molecules. In particular, we functionalized silica substrates with hydroxyl groups and covalently bound acid chloride functionalized aromatic compounds, with and without an underlying adhesion layer of 3-aminopropyltriethoxysilane. We characterized the monolayer assemblies with ellipsometry, UV-vis absorption spectroscopy, FTIR spectroscopy, and fluorescence/photoemission spectroscopy, obtaining a quantitative measure of the molecular surface coverage. In order to understand the nature of these molecular assemblies, we also pursued an in-depth kinetic study to control and optimize the monolayer formation process. Through use of UV-vis spectroscopy, we determined that the monolayer formation can best be modeled with diffusion-limited Langmuir kinetics. Specifically, we concluded that for anthracene acid chloride in dichloromethane the average diffusion coefficient was 1.6x10-7 cm2/sec. Additionally, we find we are able to achieve surface coverages of approximately 2x1014 molecules/cm2. Having established the ability to create ordered molecular assemblies, through surface functionalization, enabling covalent or highly associative binding, we continued to explore the field of molecular assemblies by studying the binding and structure of molecules to carbon nanostructures. Previous studies have shown that alkyl side chains and aromatic compounds, such as pyrene, will bind non-covalently to the sidewalls of carbon nanotubes through pi-pi interactions. We explored functionalization of carbon nanotubes and graphene by using microscopy to examine the adsorption of biomolecules onto nanotube sidewalls and graphene.

FAITH – Fast Assembly Inhibitor Test for HIV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hadravová, Romana; Rumlová, Michaela, E-mail: michaela.rumlova@vscht.cz; Department of Biotechnology, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague

Due to the high number of drug-resistant HIV-1 mutants generated by highly active antiretroviral therapy (HAART), there is continuing demand for new types of inhibitors. Both the assembly of the Gag polyprotein into immature and mature HIV-1 particles are attractive candidates for the blocking of the retroviral life cycle. Currently, no therapeutically-used assembly inhibitor is available. One possible explanation is the lack of a reliable and simple assembly inhibitor screening method. To identify compounds potentially inhibiting the formation of both types of HIV-1 particles, we developed a new fluorescent high-throughput screening assay. This assay is based on the quantification ofmore » the assembly efficiency in vitro in a 96-well plate format. The key components of the assay are HIV-1 Gag-derived proteins and a dual-labelled oligonucleotide, which emits fluorescence only when the assembly of retroviral particles is inhibited. The method was validated using three (CAI, BM2, PF74) reported assembly inhibitors. - Highlights: • Allows screening of assembly inhibitors of both mature and immature HIV-1 particles. • Based on Gag-derived proteins with CA in mature or immature conformation. • Simple and sensitive method suitable for high-throughput screening of inhibitors. • Unlike in other HIV assembly methods, works under physiological conditions. • No washing steps are necessary.« less

Recent advances in self-assembled monolayers based biomolecular electronic devices.

PubMed

Arya, Sunil K; Solanki, Pratima R; Datta, Monika; Malhotra, Bansi D

2009-05-15

Self-assembled monolayers (SAMs) have aroused much interest due to their potential applications in biosensors, biomolecular electronics and nanotechnology. This has been largely attributed to their inherent ordered arrangement and controllable properties. SAMs can be formed by chemisorption of organic molecules containing groups like thiols, disulphides, amines, acids or silanes, on desired surfaces and can be used to fabricate biomolecular electronic devices. We focus on recent applications of organosulphur compounds (thiols) based SAMs to biomolecular electronic devices in the last about 3 years.

Programmable full-adder computations in communicating three-dimensional cell cultures.

PubMed

Ausländer, David; Ausländer, Simon; Pierrat, Xavier; Hellmann, Leon; Rachid, Leila; Fussenegger, Martin

2018-01-01

Synthetic biologists have advanced the design of trigger-inducible gene switches and their assembly into input-programmable circuits that enable engineered human cells to perform arithmetic calculations reminiscent of electronic circuits. By designing a versatile plug-and-play molecular-computation platform, we have engineered nine different cell populations with genetic programs, each of which encodes a defined computational instruction. When assembled into 3D cultures, these engineered cell consortia execute programmable multicellular full-adder logics in response to three trigger compounds.

Assembly of N,N-disubstituted hydrazines and 1-aryl-1H-indazoles via copper-catalyzed coupling reactions.

PubMed

Xiong, Xiaodong; Jiang, Yongwen; Ma, Dawei

2012-05-18

CuI-catalyzed coupling of N-acyl-N'-substituted hydrazines with aryl iodides takes place at 60-90 °C to afford N-acyl-N',N'-disubstituted hydrazines regioselectively and thereby gives a facile method for assembling N,N-diaryl hydrazines. N-Acyl-N'-substituted hydrazines can also react with 2-bromoarylcarbonylic compounds at 60-125 °C under the catalysis of CuI/4-hydroxy-l-proline to provide 1-aryl-1H-indazoles.

The polymeric nanofilm of triazinedithiolsilane fabricated by self-assembled technique on copper surface. Part 2: Characterization of composition and morphology

NASA Astrophysics Data System (ADS)

Wang, Yabin; Liu, Zhong; Huang, Yudong; Qi, Yutai

2015-11-01

In the first part, a novel design route for metal protection against corrosion was proposed, and a class of triazinedithiolsilane compounds was conceived as protector for copper. The protective capability of the polymeric nanofilm, fabricated by self-assembling one representative (abbreviated as TESPA) of triazinedithiolsilane compounds onto copper surface, has been investigated and evaluated by electrochemical tests. The results show that the polymeric nanofilm significantly inhibits copper corrosion. This study, on the one hand, concentrates on the chemical composition of the TESPA polymeric nanofilm by means of X-ray photoelectron spectroscopy (XPS). The XPS results reveal that the chemical bonds between copper and TESPA monomers, three dimensional disulfide units and siloxane networks are responsible for the satisfactory protection of TESPA polymeric nanofilm against copper corrosion. On the other hand, scanning electron microscope (SEM) and energy-dispersive spectroscopy (EDS) are utilized to reveal the morphology and the uniformity of the TESPA polymeric nanofilm. The SEM-EDS results demonstrate that the copper surfaces are uniformly covered with TESPA self-assembled monolayer and the polymeric nanofilm. The TESPA-covered copper surfaces turn out to be smoother than that of the bare copper surface.

Pyridoxamine driven selective turn-off detection of picric acid using glutathione stabilized fluorescent copper nanoclusters and its applications with chemically modified cellulose strips.

PubMed

Patel, Ravi; Bothra, Shilpa; Kumar, Rajender; Crisponi, Guido; Sahoo, Suban K

2018-04-15

The present work reports the interaction of various vitamin B 6 cofactors with the red emitting glutathione stabilized copper nanoclusters (GSH-CuNCs). Addition of pyridoxamine (PM) resulted a new turn-on band at 410nm due to the possible adsorption over the surface of GSH-CuNCs. The nano-assembly PM-GSH-CuNCs was applied for the selective detection of nitro-aromatic compounds. Upon addition of picric acid (PA), the fluorescence of PM-GSH-CuNCs was selectively quenched at 410nm and ~ 625nm among the other tested nitro-aromatic compounds. With a linearity range from 9.9μM to 43μM, the concentration of PA can be detected down to 2.74μM. The high selectivity exhibited by the nano-assembly allows to detect PA in real samples like tap water, river water and matchstick. Advantageously, the nano-assembly PM-GSH-CuNCs was chemically adsorbed over the cellulosic strips and applied for the naked-eye detection of PA down to 1μM. Copyright © 2017 Elsevier B.V. All rights reserved.

Engineering self-assembled bioreactors from protein microcompartments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Savage, David

2016-10-12

The goals of this research are to understand how organisms such as bacteria segregate certain metabolic processes inside of specific structures, or “microcompartments,” in the cell and apply this knowledge to develop novel engineered microcompartments for use in nanotechnology and metabolic engineering. For example, in some bacteria, self-assembling protein microcompartments called carboxysomes encapsulate the enzymes involved in carbon fixation, enabling the cell to utilize carbon dioxide more effectively than if the enzymes were free in the cell. The proposed research will determine how structures such as carboxysomes assemble and function in bacteria and develop a means for creating novel, syntheticmore » microcompartments for optimizing production of specific energy-rich compounds.« less

The continuity of bacterial and physicochemical evolution: theory and experiments.

PubMed

Spitzer, Jan

2014-01-01

The continuity of chemical and biological evolution, incorporating life's emergence, can be explored experimentally by energizing 'dead' bacterial biomacromolecules with nutrients under cycling physicochemical gradients. This approach arises from three evolutionary principles rooted in physical chemistry: (i) broken bacterial cells cannot spontaneously self-assemble into a living state without the supply of external energy - 2nd law of thermodynamics, (ii) the energy delivery must be cycling - the primary mechanism of chemical evolution at rotating planetary surfaces under solar irradiation, (iii) the cycling energy must act on chemical mixtures of high molecular diversity and crowding - provided by dead bacterial populations. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Glyceraldehyde and glycolaldehyde in interstellar ice analogues and the role of aldehydes in cosmochemical evolution

NASA Astrophysics Data System (ADS)

Meierhenrich, U.; de Marcellus, P.; Meinert, C.; Myrgorodska, I.; Nahon, L.; Buhse, T.; d'Hendecourt, L.

2015-10-01

Our understanding of the molecular origin of life is based on amino acids, ribose, and nucleobases that - after their selection by prebiotic processes - initiated the evolutionary assembly of catalytic and informational polymers, being proteins and ribonucleic acids. Following previous amino acid identifications in the room-temperature residues of simulated circumstellar/interstellar ices [1,2] we have searched for a different family of molecules of potential prebiotic interest. Using multidimensional gas chromatography coupled to time-of-flight mass spectrometry, we have detected ten aldehydes, including the sugar-related glycolaldehyde and glyceraldehyde - two species considered as key prebiotic intermediates in the first steps toward the synthesis of ribonucleotides in a planetary environment.

Design of a monitor and simulation terminal (master) for space station telerobotics and telescience

NASA Technical Reports Server (NTRS)

Lopez, L.; Konkel, C.; Harmon, P.; King, S.

1989-01-01

Based on Space Station and planetary spacecraft communication time delays and bandwidth limitations, it will be necessary to develop an intelligent, general purpose ground monitor terminal capable of sophisticated data display and control of on-orbit facilities and remote spacecraft. The basic elements that make up a Monitor and Simulation Terminal (MASTER) include computer overlay video, data compression, forward simulation, mission resource optimization and high level robotic control. Hardware and software elements of a MASTER are being assembled for testbed use. Applications of Neural Networks (NNs) to some key functions of a MASTER are also discussed. These functions are overlay graphics adjustment, object correlation and kinematic-dynamic characterization of the manipulator.

History of Hubble Space Telescope (HST)

NASA Image and Video Library

1995-12-01

This deepest-ever view of the universe unveils myriad galaxies back to the begirning of time. Several hundred, never-before-seen, galaxies are visible in this view of the universe, called Hubble Deep Field (HDF). Besides the classical spiral and elliptical shaped galaxies, there is a bewildering variety of other galaxy shapes and colors that are important clues to understanding the evolution of the universe. Some of the galaxies may have formed less than one-billion years after the Big Bang. The image was assembled from many separate exposures with the Wide Field/Planetary Camera 2 (WF/PC2), for ten consecutive days between December 18, 1995 and December 28, 1995. This true-color view was assembled from separate images taken with blue, red, and infrared light. By combining these separate images into a single color picture, astronomers will be able to infer, at least statistically, the distance, age, and composition of galaxies in the field. Blue objects contain young stars and/or are relatively close, while redder objects contain older stellar populations and/or are farther away.

Gas-Liquid Two-Phase Flows Through Packed Bed Reactors in Microgravity

NASA Technical Reports Server (NTRS)

Motil, Brian J.; Balakotaiah, Vemuri

2001-01-01

The simultaneous flow of gas and liquid through a fixed bed of particles occurs in many unit operations of interest to the designers of space-based as well as terrestrial equipment. Examples include separation columns, gas-liquid reactors, humidification, drying, extraction, and leaching. These operations are critical to a wide variety of industries such as petroleum, pharmaceutical, mining, biological, and chemical. NASA recognizes that similar operations will need to be performed in space and on planetary bodies such as Mars if we are to achieve our goals of human exploration and the development of space. The goal of this research is to understand how to apply our current understanding of two-phase fluid flow through fixed-bed reactors to zero- or partial-gravity environments. Previous experiments by NASA have shown that reactors designed to work on Earth do not necessarily function in a similar manner in space. Two experiments, the Water Processor Assembly and the Volatile Removal Assembly have encountered difficulties in predicting and controlling the distribution of the phases (a crucial element in the operation of this type of reactor) as well as the overall pressure drop.

Layer-by-layer self-assembly in the development of electrochemical energy conversion and storage devices from fuel cells to supercapacitors.

PubMed

Xiang, Yan; Lu, Shanfu; Jiang, San Ping

2012-11-07

As one of the most effective synthesis tools, layer-by-layer (LbL) self-assembly technology can provide a strong non-covalent integration and accurate assembly between homo- or hetero-phase compounds or oppositely charged polyelectrolytes, resulting in highly-ordered nanoscale structures or patterns with excellent functionalities and activities. It has been widely used in the developments of novel materials and nanostructures or patterns from nanotechnologies to medical fields. However, the application of LbL self-assembly in the development of highly efficient electrocatalysts, specific functionalized membranes for proton exchange membrane fuel cells (PEMFCs) and electrode materials for supercapacitors is a relatively new phenomenon. In this review, the application of LbL self-assembly in the development and synthesis of key materials of PEMFCs including polyelectrolyte multilayered proton-exchange membranes, methanol-blocking Nafion membranes, highly uniform and efficient Pt-based electrocatalysts, self-assembled polyelectrolyte functionalized carbon nanotubes (CNTs) and graphenes will be reviewed. The application of LbL self-assembly for the development of multilayer nanostructured materials for use in electrochemical supercapacitors will also be reviewed and discussed (250 references).

MICROWAVE-ACCELERATED MULTICOMPONENT REACTIONS UNDER SOLVENT-FREE CONDITIONS

EPA Science Inventory

The application of microwave-accelerated solventless synthetic protocols in multicomponent (MCC) reactions will be exemplified by several condensation and cyclization reactions including the rapid one-pot assembly of valuable heterocyclic compounds from in situ generated intermed...

Colloidal Assemblies Effect on Chemical Reactions.

DTIC Science & Technology

1986-07-01

JustIfloatIon By Availability Codes Avail and/or Dist Spoial (2) RESEARCH PLANS - Photodegradation of organic compounds by visible light. Other...distribution unlimited Participating scientific personel Edmondo PRAVAURO Associate Professor Claudio MINERO Associate Researcher op p LIST OF

Nature-Inspired One-Step Green Procedure for Enhancing the Antibacterial and Antioxidant Behavior of a Chitin Film: Controlled Interfacial Assembly of Tannic Acid onto a Chitin Film.

PubMed

Wang, Yuntao; Li, Jing; Li, Bin

2016-07-20

The final goal of this study was to develop antimicrobial food-contact materials based on a natural phenolic compound (tannic acid) and chitin, which is the second most abundant polysaccharide on earth, using an interfacial assembly approach. Chitin film has poor antibacterial and antioxidant ability, which limits its application in industrial fields such as active packaging. Therefore, in this study, a novel one-step green procedure was applied to introduce antibacterial and antioxidant properties into a chitin film simultaneously by incorporation of tannic acid into the chitin film through interfacial assembly. The antibacterial and antioxidant behavior of chitin film has been greatly enhanced. Hydrogen bonds and hydrophobic interaction were found to be the main driving forces for interfacial assembly. Therefore, controlled interfacial assembly of tannic acid onto a chitin film demonstrated a good way to develop functional materials that can be potentially applied in industry.

New faces of porous Prussian blue: interfacial assembly of integrated hetero-structures for sensing applications.

PubMed

Kong, Biao; Selomulya, Cordelia; Zheng, Gengfeng; Zhao, Dongyuan

2015-11-21

Prussian blue (PB), the oldest synthetic coordination compound, is a classic and fascinating transition metal coordination material. Prussian blue is based on a three-dimensional (3-D) cubic polymeric porous network consisting of alternating ferric and ferrous ions, which provides facile assembly as well as precise interaction with active sites at functional interfaces. A fundamental understanding of the assembly mechanism of PB hetero-interfaces is essential to enable the full potential applications of PB crystals, including chemical sensing, catalysis, gas storage, drug delivery and electronic displays. Developing controlled assembly methods towards functionally integrated hetero-interfaces with adjustable sizes and morphology of PB crystals is necessary. A key point in the functional interface and device integration of PB nanocrystals is the fabrication of hetero-interfaces in a well-defined and oriented fashion on given substrates. This review will bring together these key aspects of the hetero-interfaces of PB nanocrystals, ranging from structure and properties, interfacial assembly strategies, to integrated hetero-structures for diverse sensing.

Adhesives, fillers and potting compounds. Second progress report, December 1, 1967--April 1, 1968

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lichte, H.W.; Akst, I.B.

1968-12-31

Progress in the development program whose immediate purpose is to reduce set time of a silicone compound is described. Data are presented showing that a formulation of a current RTV silicone rubber with dibutyltin diacetate has a profitably lower set time than the same rubber in the present formulation which uses dibutyltin dilaurate, without increase in probability of either reversion or penalty to other weapons components. Time to set sufficiently to allow the next assembly step is 2 to 4 hours, compared to the 16 to 24 hours presently allowed or the 8 to 12 hours minimum attainable with themore » present formulation. The reduction is of the magnitude set as a goal, the attainment of which would increase production capacity enough to reduce the amount of new construction planned to accommodate weapons assembly programs.« less

Soil Organic Matter (SOM): Molecular Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andersen, Amity

Molecular simulation is a powerful tool used to gain an atomistic, molecular, and nanoscale level understanding of the structure, dynamics, and interactions from adsorption on minerals and assembly in aggregates of soil organic matter (SOM). Given the importance of SOM fate and persistence in soils and the current knowledge gaps, applications of atomistic scale simulations to study the complex compounds in SOM and their interactions in self-assembled aggregates composed of different organic matter compounds and with mineral surfaces of different types common in soils are few and far between. Here, we describe various molecular simulation methods that are currently inmore » use in various areas and applicable to SOM research, followed by a brief survey of specific applications to SOM research and an illustration with our own recent efforts in this area. We conclude with an outlook and the challenges for future research in this area.« less

Theranostic self-assembly structure of gold nanoparticles for NIR photothermal therapy and X-Ray computed tomography imaging.

PubMed

Deng, Heng; Zhong, Yanqi; Du, Meihong; Liu, Qinjun; Fan, Zhanming; Dai, Fengying; Zhang, Xin

2014-01-01

The controllable self-assembly of amphiphilic mixed polymers grafted gold nanoparitcles (AuNPs) leads to strong interparticle plasmonic coupling, which can be tuned to the near-infrared (NIR) region for enhanced photothermal therapy (PTT). In this study, an improved thiolation method was adopted for ATRP and ROP polymer to obtain amphiphilic brushes of PMEO2MA-SH and PCL-SH. By anchoring PCL-SH and PMEO2MA-SH onto the 14 nm AuNPs, a smart hybrid building block for self-assembly was obtained. Increasing the PCL/PMEO2MA chain ratio from 0.8:1, 2:1 and 3:1 to 7:1, the structure of gold assemblies (GAs) was observed to transfer from vesicle to large compound micelle (LCM). Contributed to the special dense packed structure of gold nanoparticles in LCM, the absorption spectrometry of gold nanoparticles drastically red-shifted from 520 nm to 830 nm, which endowed the GAs remarkable NIR photothermal conversion ability. In addition, gold has high X-ray absorption coefficient which qualifies gold nanomaterial a potential CT contrast agent Herein, we obtain a novel gold assembly structure which can be utilized as potential photothermal therapeutic and CT contrast agents. In vitro and In vivo studies testified the excellent treatment efficacy of optimum GAs as a PTT and CT contrast agent. In vitro degradation test, MTT assay and histology study indicated that GAs was a safe, low toxic reagent with good biodegradability. Therefore, the optimum GAs with strong NIR absorption and high X-ray absorption coefficient could be used as a theranostic agent and the formation of novel gold large compound micelle might offers a new theory foundation for engineering design and synthesis of polymer grafted AuNPs for biomedical applications.

The Mars Organic Molecule Analyzer (MOMA) Instrument: Characterization of Organic Material in Martian Sediments

PubMed Central

Goesmann, Fred; Brinckerhoff, William B.; Raulin, François; Danell, Ryan M.; Getty, Stephanie A.; Siljeström, Sandra; Mißbach, Helge; Steininger, Harald; Arevalo, Ricardo D.; Buch, Arnaud; Freissinet, Caroline; Grubisic, Andrej; Meierhenrich, Uwe J.; Pinnick, Veronica T.; Stalport, Fabien; Szopa, Cyril; Vago, Jorge L.; Lindner, Robert; Schulte, Mitchell D.; Brucato, John Robert; Glavin, Daniel P.; Grand, Noel; Li, Xiang; van Amerom, Friso H. W.

2017-01-01

Abstract The Mars Organic Molecule Analyzer (MOMA) instrument onboard the ESA/Roscosmos ExoMars rover (to launch in July, 2020) will analyze volatile and refractory organic compounds in martian surface and subsurface sediments. In this study, we describe the design, current status of development, and analytical capabilities of the instrument. Data acquired on preliminary MOMA flight-like hardware and experimental setups are also presented, illustrating their contribution to the overall science return of the mission. Key Words: Mars—Mass spectrometry—Life detection—Planetary instrumentation. Astrobiology 17, 655–685.

Exobiology issues and experiments at a Mars base

NASA Technical Reports Server (NTRS)

Mckay, Christopher P.

1986-01-01

Research in Exobiology, the study of the origin, evolution, and distribution of life in the universe, may be a major component of the science activities at a Mars Base. Exobiology activities would include: continuing the search for life on Mars; searching for evidence for ancient life from a warmer Martian past; research into the chemistry of the biogenic elements and their compounds; and other related activities. Mars provides an opportunity in Exobiology, both for immediate study and for long range and possibly large scale experimentation in planetary biology.

Publications of the exobiology program for 1989: A special bibliography

NASA Technical Reports Server (NTRS)

1991-01-01

A listing of 1989 publications resulting from research supported by the Exobiology Program is presented. Research supported by the Exobiology Program is explored in the following areas: (1) cosmic evolution of biogenic compounds; (2) prebiotic evolution; (3) early evolution of life; (4) and evolution of advanced life. Pre-mission and pre-project activities supporting these areas are supported in the areas of solar system exploration and search for extraterrestrial intelligence. The planetary protection subject area is included here because of its direct relevance to the Exobiology Program.

Estimation and assessment of Mars contamination.

PubMed

Debus, A

2005-01-01

Since the beginning of the exploration of Mars, more than fourty years ago, thirty-six missions have been launched, including fifty-nine different space systems such as fly-by spacecraft, orbiters, cruise modules, landing or penetrating systems. Taking into account failures at launch, about three missions out of four have been successfully sent toward the Red Planet. The fact today is that Mars orbital environment includes orbiters and perhaps debris, and that its atmosphere and its surface include terrestrial compounds and dormant microorganisms. Coming from the UN Outer Space Treaty [United Nations Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies (the "Outer Space Treaty") referenced 610 UNTS 205 - resolution 2222(XXI) of December 1966] and according to the COSPAR planetary protection policy recommendations [COSPAR Planetary Protection Policy (20 October 2002), accepted by the Council and Bureau, as moved for adoption by SC F and PPP, prepared by the COSPAR/IAU Workshop on Planetary Protection, 4/02 with updates 10/0, 2002], Mars environment has to be preserved so as not to jeopardize the scientific investigations, and the level of terrestrial material brought on and around Mars theoretically has to comply with this policy. It is useful to evaluate what and how many materials, compounds and microorganisms are on Mars, to list what is in orbit and to identify where all these items are. Considering assumptions about materials, spores and gas location and dispersion on Mars, average contamination levels can be estimated. It is clear now that as long as missions are sent to other extraterrestrial bodies, it is not possible to keep them perfectly clean. Mars is one of the most concerned body, and the large number of missions achieved, on-going and planned now raise the question about its possible contamination, not necessarily from a biological point of view, but with respect to all types of contamination. Answering this question, will help to assess the potential effects of such contamination on scientific results and will address concerns relative to any ethical considerations about the contamination of other planets. c2005 COSPAR. Published by Elsevier Ltd. All rights reserved.

Diversity of Anaerobic Microbes in Spacecraft Assembly Clean Rooms ▿ †

PubMed Central

Probst, Alexander; Vaishampayan, Parag; Osman, Shariff; Moissl-Eichinger, Christine; Andersen, Gary L.; Venkateswaran, Kasthuri

2010-01-01

Although the cultivable and noncultivable microbial diversity of spacecraft assembly clean rooms has been previously documented using conventional and state-of-the-art molecular techniques, the occurrence of obligate anaerobes within these clean rooms is still uncertain. Therefore, anaerobic bacterial communities of three clean-room facilities were analyzed during assembly of the Mars Science Laboratory rover. Anaerobic bacteria were cultured on several media, and DNA was extracted from suitable anaerobic enrichments and examined with conventional 16S rRNA gene clone library, as well as high-density phylogenetic 16S rRNA gene microarray (PhyloChip) technologies. The culture-dependent analyses predominantly showed the presence of clostridial and propionibacterial strains. The 16S rRNA gene sequences retrieved from clone libraries revealed distinct microbial populations associated with each clean-room facility, clustered exclusively within gram-positive organisms. PhyloChip analysis detected a greater microbial diversity, spanning many phyla of bacteria, and provided a deeper insight into the microbial community structure of the clean-room facilities. This study presents an integrated approach for assessing the anaerobic microbial population within clean-room facilities, using both molecular and cultivation-based analyses. The results reveal that highly diverse anaerobic bacterial populations persist in the clean rooms even after the imposition of rigorous maintenance programs and will pose a challenge to planetary protection implementation activities. PMID:20228115

A Global Scale Scenario for Prebiotic Chemistry: Silica-Based Self-Assembled Mineral Structures and Formamide.

PubMed

Saladino, Raffaele; Botta, Giorgia; Bizzarri, Bruno Mattia; Di Mauro, Ernesto; Garcia Ruiz, Juan Manuel

2016-05-17

The pathway from simple abiotically made organic compounds to the molecular bricks of life, as we know it, is unknown. The most efficient geological abiotic route to organic compounds results from the aqueous dissolution of olivine, a reaction known as serpentinization (Sleep, N.H., et al. (2004) Proc. Natl. Acad. Sci. USA 101, 12818-12822). In addition to molecular hydrogen and a reducing environment, serpentinization reactions lead to high-pH alkaline brines that can become easily enriched in silica. Under these chemical conditions, the formation of self-assembled nanocrystalline mineral composites, namely silica/carbonate biomorphs and metal silicate hydrate (MSH) tubular membranes (silica gardens), is unavoidable (Kellermeier, M., et al. In Methods in Enzymology, Research Methods in Biomineralization Science (De Yoreo, J., Ed.) Vol. 532, pp 225-256, Academic Press, Burlington, MA). The osmotically driven membranous structures have remarkable catalytic properties that could be operating in the reducing organic-rich chemical pot in which they form. Among one-carbon compounds, formamide (NH2CHO) has been shown to trigger the formation of complex prebiotic molecules under mineral-driven catalytic conditions (Saladino, R., et al. (2001) Biorganic & Medicinal Chemistry, 9, 1249-1253), proton irradiation (Saladino, R., et al. (2015) Proc. Natl. Acad. Sci. USA, 112, 2746-2755), and laser-induced dielectric breakdown (Ferus, M., et al. (2015) Proc Natl Acad Sci USA, 112, 657-662). Here, we show that MSH membranes are catalysts for the condensation of NH2CHO, yielding prebiotically relevant compounds, including carboxylic acids, amino acids, and nucleobases. Membranes formed by the reaction of alkaline (pH 12) sodium silicate solutions with MgSO4 and Fe2(SO4)3·9H2O show the highest efficiency, while reactions with CuCl2·2H2O, ZnCl2, FeCl2·4H2O, and MnCl2·4H2O showed lower reactivities. The collections of compounds forming inside and outside the tubular membrane are clearly specific, demonstrating that the mineral self-assembled membranes at the same time create space compartmentalization and selective catalysis of the synthesis of relevant compounds. Rather than requiring odd local conditions, the prebiotic organic chemistry scenario for the origin of life appears to be common at a universal scale and, most probably, earlier than ever thought for our planet.

Removal of volatile organic compounds using amphiphilic cyclodextrin-coated polypropylene.

PubMed

Lumholdt, Ludmilla; Fourmentin, Sophie; Nielsen, Thorbjørn T; Larsen, Kim L

2014-01-01

Polypropylene nonwovens were functionalised using a self-assembled, amphiphilic cyclodextrin coating and the potential for water purification by removal of pollutants was studied. As benzene is one of the problematic compounds in the Water Framework Directive, six volatile organic compounds (benzene and five benzene-based substances) were chosen as model compounds. The compounds were tested as a mixture in order to provide a more realistic situation since the wastewater will be a complex mixture containing multiple pollutants. The volatile organic compounds are known to form stable inclusion complexes with cyclodextrins. Six different amphiphilic cyclodextrin derivatives were synthesised in order to elucidate whether or not the uptake abilities of the coating depend on the structure of the derivative. Headspace gas chromatography was used for quantification of the uptake exploiting the volatile nature of benzene and its derivatives. The capacity was shown to increase beyond the expected stoichiometries of guest-host complexes with ratios of up to 16:1.

Functional annotation of chemical libraries across diverse biological processes.

PubMed

Piotrowski, Jeff S; Li, Sheena C; Deshpande, Raamesh; Simpkins, Scott W; Nelson, Justin; Yashiroda, Yoko; Barber, Jacqueline M; Safizadeh, Hamid; Wilson, Erin; Okada, Hiroki; Gebre, Abraham A; Kubo, Karen; Torres, Nikko P; LeBlanc, Marissa A; Andrusiak, Kerry; Okamoto, Reika; Yoshimura, Mami; DeRango-Adem, Eva; van Leeuwen, Jolanda; Shirahige, Katsuhiko; Baryshnikova, Anastasia; Brown, Grant W; Hirano, Hiroyuki; Costanzo, Michael; Andrews, Brenda; Ohya, Yoshikazu; Osada, Hiroyuki; Yoshida, Minoru; Myers, Chad L; Boone, Charles

2017-09-01

Chemical-genetic approaches offer the potential for unbiased functional annotation of chemical libraries. Mutations can alter the response of cells in the presence of a compound, revealing chemical-genetic interactions that can elucidate a compound's mode of action. We developed a highly parallel, unbiased yeast chemical-genetic screening system involving three key components. First, in a drug-sensitive genetic background, we constructed an optimized diagnostic mutant collection that is predictive for all major yeast biological processes. Second, we implemented a multiplexed (768-plex) barcode-sequencing protocol, enabling the assembly of thousands of chemical-genetic profiles. Finally, based on comparison of the chemical-genetic profiles with a compendium of genome-wide genetic interaction profiles, we predicted compound functionality. Applying this high-throughput approach, we screened seven different compound libraries and annotated their functional diversity. We further validated biological process predictions, prioritized a diverse set of compounds, and identified compounds that appear to have dual modes of action.

Water vapor in the spectrum of the extrasolar planet HD 189733b. I. The transit

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCullough, P. R.; Crouzet, N.; Deming, D.

2014-08-10

We report near-infrared spectroscopy of the gas giant planet HD 189733b in transit. We used the Hubble Space Telescope Wide Field Camera 3 (HST WFC3) with its G141 grism covering 1.1 μm to 1.7 μm and spatially scanned the image across the detector at 2'' s{sup –1}. When smoothed to 75 nm bins, the local maxima of the transit depths in the 1.15 μm and 1.4 μm water vapor features are, respectively, 83 ± 53 ppm and 200 ± 47 ppm greater than the local minimum at 1.3 μm. We compare the WFC3 spectrum with the composite transit spectrum ofmore » HD 189733b assembled by Pont et al., extending from 0.3 μm to 24 μm. Although the water vapor features in the WFC3 spectrum are compatible with the model of non-absorbing, Rayleigh-scattering dust in the planetary atmosphere, we also re-interpret the available data with a clear planetary atmosphere. In the latter interpretation, the slope of increasing transit depth with shorter wavelengths from the near infrared, through the visible, and into the ultraviolet is caused by unocculted star spots, with a smaller contribution of Rayleigh scattering by molecular hydrogen in the planet's atmosphere. At relevant pressures along the terminator, our model planetary atmosphere's temperature is ∼700 K, which is below the condensation temperatures of sodium- and potassium-bearing molecules, causing the broad wings of the spectral lines of Na I and K I at 0.589 μm and 0.769 μm to be weak.« less

Planetary Load Sharing in Three-Point- Mounted Wind Turbine Gearboxes: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo, Yi; Keller, Jonathan A

Wind turbine gearboxes do not achieve their expected design life. The cost of gearbox replacements and rebuilds and the downtime associated with these failures increase the cost of wind energy. In 2007, the U.S. Department of Energy established the National Renewable Energy Laboratory (NREL) Gearbox Reliability Collaborative (GRC). Its goals are to understand the root causes of premature gearbox failures and improve their reliability. To date, the GRC has focused on a 750-kW drivetrain with a three-stage, three-point-mounted gearbox. A nonproprietary version of the gearbox containing CRBs with C3 clearances in the planetary stage was customized. Two of these gearboxes,more » GB1 and GB2, were manufactured and then tested in the National Wind Technology Center's 2.5-MW dynamometer and in the field. Major GRC findings include the detrimental effect of rotor moments on planetary load sharing and predicted fatigue, and the risk of bearing sliding in low-torque conditions for three-point configuration drivetrains. Based on the knowledge gained from testing and analysis of the original design, the GRC gearbox was redesigned to improve its load-sharing characteristics and predicted fatigue. This new gearbox is named GB3. As shown in Figure 1, its key improvement is the incorporation of preloaded TRBs that support the planet carrier and planets. Roller loads can be optimized and bearing life maximized with a small preload [4]. These preloaded bearings, along with interference-fitted planet pins, improve alignments and load-sharing characteristics. A semi-integrated planet bearing design also increases capacity and eliminates outer race fretting. Romax Technology, with Powertrain Engineers and the Timken Company (Timken), completed the redesign. Timken manufactured and instrumented the planet gears and bearings. Brad Foote Gearing manufactured the other gearing and assembled the gearbox.« less

Hardware Architecture and Cutting-Edge Assembly Process of a Tiny Curved Compound Eye

PubMed Central

Viollet, Stéphane; Godiot, Stéphanie; Leitel, Robert; Buss, Wolfgang; Breugnon, Patrick; Menouni, Mohsine; Juston, Raphaël; Expert, Fabien; Colonnier, Fabien; L'Eplattenier, Géraud; Brückner, Andreas; Kraze, Felix; Mallot, Hanspeter; Franceschini, Nicolas; Pericet-Camara, Ramon; Ruffier, Franck; Floreano, Dario

2014-01-01

The demand for bendable sensors increases constantly in the challenging field of soft and micro-scale robotics. We present here, in more detail, the flexible, functional, insect-inspired curved artificial compound eye (CurvACE) that was previously introduced in the Proceedings of the National Academy of Sciences (PNAS, 2013). This cylindrically-bent sensor with a large panoramic field-of-view of 180° × 60° composed of 630 artificial ommatidia weighs only 1.75 g, is extremely compact and power-lean (0.9 W), while it achieves unique visual motion sensing performance (1950 frames per second) in a five-decade range of illuminance. In particular, this paper details the innovative Very Large Scale Integration (VLSI) sensing layout, the accurate assembly fabrication process, the innovative, new fast read-out interface, as well as the auto-adaptive dynamic response of the CurvACE sensor. Starting from photodetectors and microoptics on wafer substrates and flexible printed circuit board, the complete assembly of CurvACE was performed in a planar configuration, ensuring high alignment accuracy and compatibility with state-of-the art assembling processes. The characteristics of the photodetector of one artificial ommatidium have been assessed in terms of their dynamic response to light steps. We also characterized the local auto-adaptability of CurvACE photodetectors in response to large illuminance changes: this feature will certainly be of great interest for future applications in real indoor and outdoor environments. PMID:25407908

Technology of welding aluminum alloys-IV

NASA Technical Reports Server (NTRS)

Ginez, R.; Lewis, J. R.; Millett, A. U.; Saenger, K. A.; Skelly, J. K.; Standiford, V. E.; Whiteman, J. O.

1978-01-01

Skate-weld carriage and track assembly were developed for controlled fusion welding on compound-curvature surfaces. Unlike fixed-position carriage used for vertical, horizontal, and circumferential welding, carriage has suspension system that permits angular positioning of weld head on carriage. It also has carriage-and-drive track mechanism capable of traveling over compound curvatures. Carriage is designed with universal mounting platform so that slim tools, weld heads, or X-ray units can be interchanged without need for realinement.

Solid-phase organic synthesis of difluoroalkyl entities using a novel fluorinating cleavage strategy: part 2. Synthesis of three small gem-difluorinated compound libraries using a dithiane linker.

PubMed

Wiehn, Matthias S; Fürniss, Daniel; Bräse, Stefan

2009-01-01

Three small compound biaryl libraries featuring a novel fluorinating cleavage strategy for preparation of a difluoromethyl group were assembled on solid supports. The average reaction yield per step was up to 96% in a synthetic sequence over five to six steps. Key features were Suzuki coupling reactions, transesterification with potassium cyanide and amidation reaction with trimethyl aluminum on solid supports.

MICROWAVE-FACILITATED MULTICOMPONENT REACTIONS UNDER SOLVENT-FREE CONDITIONS

EPA Science Inventory

The application of microwave-expedited solvent-free synthetic protocols in multi-component (MCC) reactions will be exemplified by several condensation and cyclization reactions including the rapid one-pot assembly of heterocyclic compounds from in situ generated intermediates. R...

Metamagnetism in hydrophobically induced carboxylate (phenylmalonate)-bridged copper(II) layers.

PubMed

Pasán, Jorge; Sanchiz, Joaquín; Ruiz-Pérez, Catalina; Campo, Javier; Lloret, Francesc; Julve, Miguel

2006-07-21

Self-assembly of copper(l) ions, phenylmalonate and pyrimidine yields the layered compound [Cu(pym)(Phmal)n (1) where intralayer ferro- and interlayer antiferromagnetic interactions occur with three-dimensional antiferromagnetic ordering at T(c) = 2.15 K.

A rapid and rational approach to generating isomorphous heavy-atom phasing derivatives

PubMed Central

Lu, Jinghua; Sun, Peter D.

2014-01-01

In attempts to replace the conventional trial-and-error heavy-atom derivative search method with a rational approach, we previously defined heavy metal compound reactivity against peptide ligands. Here, we assembled a composite pH and buffer-dependent peptide reactivity profile for each heavy metal compound to guide rational heavy-atom derivative search. When knowledge of the best-reacting heavy-atom compound is combined with mass spectrometry-assisted derivatization, and with a quick-soak method to optimize phasing, it is likely that the traditional heavy-atom compounds could meet the demand of modern high-throughput X-ray crystallography. As an example, we applied this rational heavy-atom phasing approach to determine a previously unknown mouse serum amyloid A2 crystal structure. PMID:25040395

Diazo compounds in continuous-flow technology.

PubMed

Müller, Simon T R; Wirth, Thomas

2015-01-01

Diazo compounds are very versatile reagents in organic chemistry and meet the challenge of selective assembly of structurally complex molecules. Their leaving group is dinitrogen; therefore, they are very clean and atom-efficient reagents. However, diazo compounds are potentially explosive and extremely difficult to handle on an industrial scale. In this review, it is discussed how continuous flow technology can help to make these powerful reagents accessible on large scale. Microstructured devices can improve heat transfer greatly and help with the handling of dangerous reagents safely. The in situ formation and subsequent consumption of diazo compounds are discussed along with advances in handling diazomethane and ethyl diazoacetate. The potential large-scale applications of a given methodology is emphasized. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Smart DNA Fabrication Using Sound Waves

PubMed Central

Kanigowska, Paulina; Shen, Yue; Zheng, Yijing; Rosser, Susan; Cai, Yizhi

2016-01-01

Acoustic droplet ejection (ADE) technology uses focused acoustic energy to transfer nanoliter-scale liquid droplets with high precision and accuracy. This noncontact, tipless, low-volume dispensing technology minimizes the possibility of cross-contamination and potentially reduces the costs of reagents and consumables. To date, acoustic dispensers have mainly been used in screening libraries of compounds. In this paper, we describe the first application of this powerful technology to the rapidly developing field of synthetic biology, for DNA synthesis and assembly at the nanoliter scale using a Labcyte Echo 550 acoustic dispenser. We were able to successfully downscale PCRs and the popular one-pot DNA assembly methods, Golden Gate and Gibson assemblies, from the microliter to the nanoliter scale with high assembly efficiency, which effectively cut the reagent cost by 20- to 100-fold. We envision that acoustic dispensing will become an instrumental technology in synthetic biology, in particular in the era of DNA foundries. PMID:26163567

Self-assembly modes of glycyrrhetinic acid esters in view of the crystal packing of related triterpene molecules.

PubMed

Langer, Dominik; Wicher, Barbara; Szczołko, Wojciech; Gdaniec, Maria; Tykarska, Ewa

2016-08-01

The crystal structures of three ester derivatives of glycyrrhetinic acid (GE) are reported. X-ray crystallography revealed that despite differences in the size of the ester substituents (ethyl, isopropyl and 2-morpholinoethyl) the scheme of molecular self-assembly is similar in all three cases but differs significantly from that observed in other known GE esters. According to our analysis, the two basic patterns of self-assembly of GE esters observed in their unsolvated crystals correspond to two distinct orientations of the ester groups relative to the triterpene backbone. Moreover, comparison of the self-assembly modes of GE esters in their unsolvated forms with the supramolecular organization of GE and carbenoxolone in their solvated crystals revealed that ester substituents replace solvent molecules hydrogen bonded to the COOH group at the triterpene skeleton, resulting in similar packing arrangements of these compounds.

Self-assembly of [UO{sub 2}X{sub 4}]{sup 2−} (X=Cl, Br) dianions with γ substituted pyridinium cations: Structural systematics and fluorescence properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Surbella, Robert G.; Andrews, Michael B.; Cahill, Christopher L., E-mail: cahill@gwu.edu

2016-04-15

Room temperature self-assembly of [UO{sub 2}X{sub 4}]{sup 2−} (X=Cl, Br) with γ substituted pyridinium cations has resulted in the formation of twelve compounds that were studied via single crystal X-ray diffraction and fluorescence spectroscopy. Systematic variation of electron donating groups on the pyridinium species is shown to influence the presence and/or strength of various supramolecular synthons, including hydrogen bonding and pi interactions. Combinations of such non-covalent interactions (NCIs) have given rise to a range of supramolecular assemblies, and are shown to influence uranyl emission by way of second sphere coordination to equatorial ligands. - Graphical abstract: Supramolecular assembly of themore » [UO{sub 2}Cl{sub 4}]{sup 2−} dianion with pyridinium cations is a viable synthetic route to the growth of uranyl containing single crystals.« less

Synthesis, physical properties and self-assembly behavior of azole-fused pyrene derivatives

NASA Astrophysics Data System (ADS)

Xiao, Jinchong; Xiao, Xuyu; Zhao, Yanlei; Wu, Bo; Liu, Zhenying; Zhang, Xuemin; Wang, Sujuan; Zhao, Xiaohui; Liu, Lei; Jiang, Li

2013-05-01

A novel selenadiazole-fused pyrene derivative PySe was successfully synthesized and characterized. Its single structure is almost planar and adopts a sandwich-herringbone packing model. The self-assembly behaviors based on compound PySe and its analogue thiadiazole-fused pyrene derivative PyS were studied in detail and the as-formed nanostructures were fully characterized by means of UV-vis absorption, emission spectra, X-ray diffraction, field emission SEM and TEM. We attribute the bathochromic shift absorption and emission spectra of PyS and PySe in aqueous solution to the formation of J-type aggregation. In addition, our investigation demonstrated that the shape and size of the as-prepared nanostructures could be tuned by different chalcogen analogues and the volume ratio of water to organic solvent.A novel selenadiazole-fused pyrene derivative PySe was successfully synthesized and characterized. Its single structure is almost planar and adopts a sandwich-herringbone packing model. The self-assembly behaviors based on compound PySe and its analogue thiadiazole-fused pyrene derivative PyS were studied in detail and the as-formed nanostructures were fully characterized by means of UV-vis absorption, emission spectra, X-ray diffraction, field emission SEM and TEM. We attribute the bathochromic shift absorption and emission spectra of PyS and PySe in aqueous solution to the formation of J-type aggregation. In addition, our investigation demonstrated that the shape and size of the as-prepared nanostructures could be tuned by different chalcogen analogues and the volume ratio of water to organic solvent. Electronic supplementary information (ESI) available: TGA analysis, spectra characterization data for compound 1, 2, 3 and X-ray crystallographic data for compound PySe (2, CIF). CCDC 917821. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c3nr00523b

Hybrid de novo genome assembly of the Chinese herbal fleabane Erigeron breviscapus

PubMed Central

Zhang, Guanghui; Zhang, Jing; Liu, Hui; Chen, Wei; Wang, Xiao; Li, Yahe

2017-01-01

Abstract Background: The plants in the Erigeron genus of the Compositae (Asteraceae) family are commonly called fleabanes, possibly due to the belief that certain chemicals in these plants repel fleas. In the traditional Chinese medicine, Erigeron breviscapus, which is native to China, was widely used in the treatment of cerebrovascular disease. A handful of bioactive compounds, including scutellarin, 3,5-dicaffeoylquinic acid, and 3,4-dicaffeoylquinic acid, have been isolated from the plant. With the purpose of finding novel medicinal compounds and understanding their biosynthetic pathways, we propose to sequence the genome of E. breviscapus. Findings: We assembled the highly heterozygous E. breviscapus genome using a combination of PacBio single-molecular real-time sequencing and next-generation sequencing methods on the Illumina HiSeq platform. The final draft genome is approximately 1.2 Gb, with contig and scaffold N50 sizes of 18.8 kb and 31.5 kb, respectively. Further analyses predicted 37 504 protein-coding genes in the E. breviscapus genome and 8172 shared gene families among Compositae species. Conclusions: The E. breviscapus genome provides a valuable resource for the investigation of novel bioactive compounds in this Chinese herb. PMID:28431028

Resistance of spacecraft isolates to outer space for planetary protection purposes -first results of the experiment PROTECT of the EXPOSE-E mission.

NASA Astrophysics Data System (ADS)

Horneck, Gerda; Moeller, Ralf

Spore-forming microbes are of particular concern in the context of planetary protection, be-cause their endospores are highly resistant to a variety of environmental extremes, including certain sterilization procedures and the harsh environment of outer space or planetary sur-faces (Nicholson et al., 2000; Horneck et al. 2009). Furthermore, isolates from space craft and space craft assembly facilities have been identified that form spores of an elevated resistance to various physical and chemical conditions, such as ionizing and UV radiation, desiccation and oxidative stress (La Duc et al., 2007). This observation led to the supposition that the spe-cial conditions of ultraclean spacecraft assembly facilities and the applied spacecraft cleaning and decontamination measures cause a selection of the most resistant organisms as survivors. To test this hypothesis, spores of B. pumilus SAFR-032 isolated from these environments as well as spores of the laboratory strain B. subtilis 168 were subjected to selected parameters of space in the experiment PROTECT during the EXPOSE-E mission (February 7, 2008 -September 12, 2009), attached to the EuTEF platform outside of the Columbus module of the International Space Station. The spores were mounted as dry layers onto spacecraft-qualified material (aluminum coupons) and exposed to the following parameters of space, applied sep-arately or in selected combinations: (i) space vacuum, (ii) solar extraterrestrial UV radiation including vacuum-UV, (iii) simulated Mars atmosphere and UV radiation climate, and (iv) galactic cosmic radiation. After recovery, visual inspection showed color changes of the sun-exposed spore samples from white to brownish demonstrating photochemical damage caused by solar extraterrestrial UV radiation. On-going analyses include studies of viability and capabil-ity of repair of damage, mutagenic spectrum, e.g. trp-revertants, rifampicin-resistant mutants, DNA lesion, global gene expression, and genomic and proteomic characterizations using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). First viability studies gave the following survival rates: 20 -30 References: Horneck,G., D.M. Klaus, R.L. Mancinelli (2010) Space microbiology, Microb. Mol. Biol. Rev. (in press) La Duc MT, Dekas A, Osman S, Moissl C, Newcombe D, Venkateswaran K. (2007) Isolation and character-ization of bacteria capable of tolerating the extreme conditions of clean room environments. Appl Environ Microbiol. 73, 2600-11. Nicholson WL, Munakata N, Horneck G, Melosh HJ, and Setlow P (2000) Resistance of Bacillus endospores to extreme terrestrial and extraterrestrial environments, Microb. Mol. Biol. Rev. 64, 548-572.

COSPAR Workshop on Planetary Protection for Titan and Ganymede

NASA Astrophysics Data System (ADS)

Rummel, J. D.; Raulin, F.; Ehrenfreund, P.

2010-06-01

During the deliberations of the COSPAR Workshop on Planetary Protection for Outer Planet Satellites and Small Solar System Bodies (Rummel et al., 2009), held in Vienna in April 2009, a number of bodies in the outer Solar System were identified as being potentially in the "II+" category consistent with the COSPAR categorization scheme, referring to a body that is of interest to chemical evolution and the origin of life, but whose potential to support living organisms is undecided, including at least Titan, Ganymede, Triton, and the Pluto-Charon system (see Appendix C). Of these objects, Titan is the highest priority target for a near-term robotic flagship mission and Ganymede is also the subject of flagship mission interest. To address the concerns that were raised in Vienna about the categorization of Titan and Ganymede (as "II+") required another dedicated workshop to concentrate on those two bodies, a meeting was planned and held jointly by NASA, ESA, and COSPAR during the winter of 2009- 2010. This workshop included additional experts on Titan and Ganymede who were not able to participate in the Vienna meeting, and allowed the attendees to inspect detailed information about the most recent Cassini-Huygens results as well as the most current interpretation of the data available for both Titan and Ganymede. The goal of this workshop was to resolve the mission category for Titan and Ganymede and to develop a consensus on the II versus II+ dichotomy, taking into account both the conservative nature of planetary protection policy and the physical constraints on the Titan system and on Ganymede - the two largest moons in our solar system. This report summarizes the findings and recommendations from the workshop. The document will be distributed to the COSPAR Planetary Protection panel for consideration prior to the next General Assembly meeting in Bremen (Germany) during July 2010. Results from the Titan/Ganymede study will also be coordinated in a larger evaluation of outer planet icy satellites that has been requested from the US National Research Council.

Self-organisation of dodeca-dendronized fullerene into supramolecular discs and helical columns containing a nanowire-like core.

PubMed

Guerra, Sebastiano; Iehl, Julien; Holler, Michel; Peterca, Mihai; Wilson, Daniela A; Partridge, Benjamin E; Zhang, Shaodong; Deschenaux, Robert; Nierengarten, Jean-François; Percec, Virgil

2015-06-01

Twelve chiral and achiral self-assembling dendrons have been grafted onto a [60]fullerene hexa-adduct core by copper-catalyzed alkyne azide "click" cycloaddition. The structure adopted by these compounds was determined by the self-assembling peripheral dendrons. These twelve dendrons mediate the self-organisation of the dendronized [60]fullerene into a disc-shaped structure containing the [60]fullerene in the centre. The fullerene-containing discs self-organise into helical supramolecular columns with a fullerene nanowire-like core, forming a 2D columnar hexagonal periodic array. These unprecedented supramolecular structures and their assemblies are expected to provide new developments in chiral complex molecular systems and their application to organic electronics and solar cells.

Hydrogen bond-Driven Self-Assembly between Amidinium Cations and Carboxylate Anions: A Combined Molecular Dynamics, NMR Spectroscopy, and Single Crystal X-ray Diffraction Study.

PubMed

Thomas, Michael; Anglim Lagones, Thomas; Judd, Martyna; Morshedi, Mahbod; O'Mara, Megan L; White, Nicholas G

2017-07-04

A combination of molecular dynamics (MD), NMR spectroscopy, and single crystal X-ray diffraction (SCXRD) techniques was used to probe the self-assembly of para- and meta-bis(amidinium) compounds with para-, meta-, and ortho-dicarboxylates. Good concordance was observed between the MD and experimental results. In DMSO solution, the systems form several rapidly exchanging assemblies, in part because a range of hydrogen bonding interactions is possible between the amidinium and carboxylate moieties. Upon crystallization, the majority of the systems form 1D supramolecular polymers, which are held together by short N-H⋅⋅⋅O hydrogen bonds. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Investigating the Co-Adsorption Behavior of Nucleic-Acid Base (Thymine and Cytosine) and Melamine at Liquid/Solid Interface

NASA Astrophysics Data System (ADS)

Zhao, Huiling; Li, Yinli; Chen, Dong; Liu, Bo

2016-12-01

The co-adsorption behavior of nucleic-acid base (thymine; cytosine) and melamine was investigated by scanning tunneling microscopy (STM) technique at liquid/solid (1-octanol/graphite) interface. STM characterization results indicate that phase separation happened after dropping the mixed solution of thymine-melamine onto highly oriented pyrolytic graphite (HOPG) surface, while the hetero-component cluster-like structure was observed when cytosine-melamine binary assembly system is used. From the viewpoints of non-covalent interactions calculated by using density functional theory (DFT) method, the formation mechanisms of these assembled structures were explored in detail. This work will supply a methodology to design the supramolecular assembled structures and the hetero-component materials composed by biological and chemical compound.

Composition of LHB Comets and Their Influence on the Early Earth Atmosphere Composition

NASA Technical Reports Server (NTRS)

Tornow, C.; Kupper, S.; Ilgner, M.; Kuehrt, E.; Motschmann, U.

2011-01-01

Two main processes were responsible for the composition of this atmosphere: chemical evolution of the volatile fraction of the accretion material forming the planet and the delivery of gasses to the planetary surface by impactors during the late heavy bombardment (LHB). The amount and composition of the volatile fraction influences the outgassing of the Earth mantle during the last planetary formation period. A very weakened form of outgassing activity can still be observed today by examining the composition of volcanic gasses. An enlightenment of the second process is based on the sparse records of the LHB impactors resulting from the composition of meteorites, observed cometary comas, and the impact material found on the Moon. However, for an assessment of the influence of the outgassing on the one hand and the LHB event on the other, one has to supplement the observations with numerical simulations of the formation of volatiles and their incorporation into the accretion material which is the precursors of planetary matter, comets and asteroids. These simulations are performed with a combined hydrodynamic-chemical model of the solar nebula (SN). We calculate the chemical composition of the gas and dust phase of the SN. From these data, we draw conclusions on the upper limits of the water content and the amount of carbon and nitrogen rich volatiles incorporated later into the accretion material. Knowing these limits we determine the portion of major gas compounds delivered during the LHB and compare it with the related quantities of the outgassed species.

HUBBLE CAPTURES DETAILED IMAGE OF URANUS' ATMOSPHERE

NASA Technical Reports Server (NTRS)

2002-01-01

Hubble Space Telescope has peered deep into Uranus' atmosphere to see clear and hazy layers created by a mixture of gases. Using infrared filters, Hubble captured detailed features of three layers of Uranus' atmosphere. Hubble's images are different from the ones taken by the Voyager 2 spacecraft, which flew by Uranus 10 years ago. Those images - not taken in infrared light - showed a greenish-blue disk with very little detail. The infrared image allows astronomers to probe the structure of Uranus' atmosphere, which consists of mostly hydrogen with traces of methane. The red around the planet's edge represents a very thin haze at a high altitude. The haze is so thin that it can only be seen by looking at the edges of the disk, and is similar to looking at the edge of a soap bubble. The yellow near the bottom of Uranus is another hazy layer. The deepest layer, the blue near the top of Uranus, shows a clearer atmosphere. Image processing has been used to brighten the rings around Uranus so that astronomers can study their structure. In reality, the rings are as dark as black lava or charcoal. This false color picture was assembled from several exposures taken July 3, 1995 by the Wide Field Planetary Camera-2. CREDIT: Erich Karkoschka (University of Arizona Lunar and Planetary Lab) and NASA

Terrestrial Zone Exoplanets and Life

NASA Astrophysics Data System (ADS)

Matthews, Brenda

2018-01-01

One of the most exciting results from ALMA has been the detection of significant substructure within protoplanetary disks that can be linked to planet formation processes. For the first time, we are able to observe the process of assembly of material into larger bodies within such disks. It is not possible, however, for ALMA to probe the growth of planets in protoplanetary disks at small radii, i.e., in the terrestrial zone, where we expect rocky terrestrial planets to form. In this regime, the optical depths prohibit observation at the high frequencies observed by ALMA. To probe the effects of planet building processes and detect telltale gaps and signatures of planetary mass bodies at such small separations from the parent star, we require a facility of superior resolution and sensitivity at lower frequencies. The ngVLA is just such a facility. We will present the fundamental science that will be enabled by the ngVLA in protoplanetary disk structure and the formation of planets. In addition, we will discuss the potential for an ngVLA facility to detect the molecules that are the building blocks of life, reaching limits well beyond those reachable with the current generation of telescopes, and also to determine whether such planets will be habitable based on studies of the impact of stars on their nearest planetary neighbours.

Greener Synthesis of Organics and Nanomaterials

EPA Science Inventory

A brief account of reactions involving microwave (MW) exposure of neat reactants or catalyzed by mineral support surfaces, such as alumina, silica, clay, or their ‘doped’ versions, for the rapid one-pot assembly of heterocyclic compounds from in situ generated reactive intermedia...

40 CFR 129.105 - Polychlorinated biphenyls (PCBs).

Code of Federal Regulations, 2010 CFR

2010-07-01

... dielectric. (3) Electrical transformer manufacturer means a manufacturer who produces or assembles electrical transformers in which PCB or PCB-containing compounds are part of the dielectric. (4) The ambient water... manufacturer. (d) Electrical transformer manufacturer—(1) Applicability. (i) These standards or prohibitions...

40 CFR 129.105 - Polychlorinated biphenyls (PCBs).

Code of Federal Regulations, 2014 CFR

2014-07-01

... dielectric. (3) Electrical transformer manufacturer means a manufacturer who produces or assembles electrical transformers in which PCB or PCB-containing compounds are part of the dielectric. (4) The ambient water... manufacturer. (d) Electrical transformer manufacturer—(1) Applicability. (i) These standards or prohibitions...

40 CFR 129.105 - Polychlorinated biphenyls (PCBs).

Code of Federal Regulations, 2011 CFR

2011-07-01

... dielectric. (3) Electrical transformer manufacturer means a manufacturer who produces or assembles electrical transformers in which PCB or PCB-containing compounds are part of the dielectric. (4) The ambient water... manufacturer. (d) Electrical transformer manufacturer—(1) Applicability. (i) These standards or prohibitions...

40 CFR 129.105 - Polychlorinated biphenyls (PCBs).

Code of Federal Regulations, 2012 CFR

2012-07-01

... dielectric. (3) Electrical transformer manufacturer means a manufacturer who produces or assembles electrical transformers in which PCB or PCB-containing compounds are part of the dielectric. (4) The ambient water... manufacturer. (d) Electrical transformer manufacturer—(1) Applicability. (i) These standards or prohibitions...

40 CFR 129.105 - Polychlorinated biphenyls (PCBs).

Code of Federal Regulations, 2013 CFR

2013-07-01

... dielectric. (3) Electrical transformer manufacturer means a manufacturer who produces or assembles electrical transformers in which PCB or PCB-containing compounds are part of the dielectric. (4) The ambient water... manufacturer. (d) Electrical transformer manufacturer—(1) Applicability. (i) These standards or prohibitions...

Surface confined metallosupramolecular architectures: formation and scanning tunneling microscopy characterization.

PubMed

Li, Shan-Shan; Northrop, Brian H; Yuan, Qun-Hui; Wan, Li-Jun; Stang, Peter J

2009-02-17

Metallosupramolecular compounds have attracted a great deal of attention over the past two decades largely because of their unique, highly complex structural characteristics and their potential electronic, magnetic, optical, and catalytic properties. These molecules can be prepared with relative ease using coordination-driven self-assembly techniques. In particular, the use of electron-poor square-planar Pt(II) transition metals in conjunction with rigid, electron-rich pyridyl donors has enabled the spontaneous self-assembly of a rich library of 2D metallacyclic and 3D metallacage assemblies via the directional-bonding approach. With this progress in the preparation and characterization of metallosupramolecules, researchers have now turned their attention toward fully exploring and developing their materials properties. Assembling metallosupramolecular compounds on solid supports represents a vitally important step toward developing their materials properties. Surfaces provide a means of uniformly aligning and orienting these highly symmetric metallacycles and metallacages. This uniformity increases the level of coherence between molecules above that which can be achieved in the solution phase and provides a way to integrate adsorbed layers, or adlayers, into a solid-state materials setting. The dynamic nature of kinetically labile Pt(II)-N coordination bonds requires us to adjust deposition and imaging conditions to retain the assemblies' stability. Toward these aims, we have used scanning tunneling microscopy (STM) to image these adlayers and to understand the factors that govern surface self-assembly and the interactions that influence their structure and stability. This Account describes our efforts to deposit 2D rectangular and square metallacycles and 3D trigonal bipyramidal and chiral trigonal prism metallacages on highly oriented pyrolytic graphite (HOPG) and Au(111) substrates to give intact assemblies and ordered adlayers. We have investigated the effects of varying the size, symmetry, and dimensionality of supramolecular adsorbates, the choice of substrate, the use of a molecular template, and the effects of chirality. Our systematic investigations provide insights into the various adsorbate-adsorbate and substrate-adsorbate interactions that largely determine the architecture of each assembly and affect their performance in a materials setting. Rational control over adlayer formation and structure will greatly enhance the potential of these supramolecules to be used in a variety of applications such as host-guest sensing/diagnostic systems, molecular electronic devices, and heterogeneous stereoselective synthesis and catalysis.

Methods of making composite optical devices employing polymer liquid crystal

DOEpatents

Jacobs, Stephen D.; Marshall, Kenneth L.; Cerqua, Kathleen A.

1991-01-01

Composite optical devices using polymer liquid crystal materials both as optical and adhesive elements. The devices are made by assembling a heated polymer liquid crystal compound, while in a low viscosity form between optically transparent substrates. The molecules of the polymer are oriented, while in the liquid crystalline state and while above the glass transition temperature (T.sub.g) of the polymer, to provide the desired optical effects, such as polarization, and selective reflection. The liquid crystal polymer cements the substrates together to form an assembly providing the composite optical device.

Iterative Coupling of Two Different Enones by Nitromethane Using Bifunctional Thiourea Organocatalysts. Stereocontrolled Assembly of Cyclic and Acyclic Structures.

PubMed

Varga, Szilárd; Jakab, Gergely; Csámpai, Antal; Soós, Tibor

2015-09-18

An organocatalytic iterative assembly line has been developed in which nitromethane was sequentially coupled with two different enones using a combination of pseudoenantiomeric cinchona-based thiourea catalysts. Application of unsaturated aldehydes and ketones in the second step of the iterative sequence allows the construction of cyclic syn-ketols and acyclic compounds with multiple contiguous stereocenters. The combination of the multifunctional substrates and ambident electrophiles rendered some organocatalytic transformations possible that have not yet been realized in bifunctional noncovalent organocatalysis.

Graphene macro-assembly-fullerene composite for electrical energy storage

DOEpatents

Campbell, Patrick G.; Baumann, Theodore F.; Biener, Juergen; Merrill, Matthew; Montalvo, Elizabeth; Worsley, Marcus A.; Biener, Monika M.; Hernandez, Maira Raquel Ceron

2018-01-16

Disclosed here is a method for producing a graphene macro-assembly (GMA)-fullerene composite, comprising providing a GMA comprising a three-dimensional network of graphene sheets crosslinked by covalent carbon bonds, and incorporating at least 20 wt. % of at least one fullerene compound into the GMA based on the initial weight of the GMA to obtain a GMA-fullerene composite. Also described are a GMA-fullerene composite produced, an electrode comprising the GMA-fullerene composite, and a supercapacitor comprising the electrode and optionally an organic or ionic liquid electrolyte in contact with the electrode.

Flexible fuel cell gas manifold system

DOEpatents

Cramer, Michael; Shah, Jagdish; Hayes, Richard P.; Kelley, Dana A.

2005-05-03

A fuel cell stack manifold system in which a flexible manifold body includes a pan having a central area, sidewall extending outward from the periphery of the central area, and at least one compound fold comprising a central area fold connecting adjacent portions of the central area and extending between opposite sides of the central area, and a sidewall fold connecting adjacent portions of the sidewall. The manifold system further includes a rail assembly for attachment to the manifold body and adapted to receive pins by which dielectric insulators are joined to the manifold assembly.

The chemistry in circumstellar envelopes of evolved stars: following the origin of the elements to the origin of life.

PubMed

Ziurys, Lucy M

2006-08-15

Mass loss from evolved stars results in the formation of unusual chemical laboratories: circumstellar envelopes. Such envelopes are found around carbon- and oxygen-rich asymptotic giant branch stars and red supergiants. As the gaseous material of the envelope flows from the star, the resulting temperature and density gradients create a complex chemical environment involving hot, thermodynamically controlled synthesis, molecule "freeze-out," shock-initiated reactions, and photochemistry governed by radical mechanisms. In the circumstellar envelope of the carbon-rich star IRC+10216, >50 different chemical compounds have been identified, including such exotic species as C(8)H, C(3)S, SiC(3), and AlNC. The chemistry here is dominated by molecules containing long carbon chains, silicon, and metals such as magnesium, sodium, and aluminum, which makes it quite distinct from that found in molecular clouds. The molecular composition of the oxygen-rich counterparts is not nearly as well explored, although recent studies of VY Canis Majoris have resulted in the identification of HCO(+), SO(2), and even NaCl in this object, suggesting chemical complexity here as well. As these envelopes evolve into planetary nebulae with a hot, exposed central star, synthesis of molecular ions becomes important, as indicated by studies of NGC 7027. Numerous species such as HCO(+), HCN, and CCH are found in old planetary nebulae such as the Helix. This "survivor" molecular material may be linked to the variety of compounds found recently in diffuse clouds. Organic molecules in dense interstellar clouds may ultimately be traced back to carbon-rich fragments originally formed in circumstellar shells.

Martian canyons and African rifts: Structural comparisons and implications

NASA Technical Reports Server (NTRS)

Frey, H. V.

1978-01-01

The resistant parts of the canyon walls of the Martian rift complex Valled Marineris were used to infer an earlier, less eroded reconstruction of the major roughs. The individual canyons were then compared with individual rifts of East Africa. When measured in units of planetary radius, Martian canyons show a distribution of lengths nearly identical to those in Africa, both for individual rifts and for compound rift systems. A common mechanism which scales with planetary radius is suggested. Martian canyons are significantly wider than African rifts. The overall pattern of the rift systems of Africa and Mars are quite different in that the African systems are composed of numerous small faults with highly variable trend. On Mars the trends are less variable; individual scarps are straighter for longer than on earth. This is probably due to the difference in tectonic histories of the two planets: the complex history of the earth and the resulting complicated basement structures influence the development of new rifts. The basement and lithosphere of Mars are inferred to be simple, reflecting a relatively inactive tectonic history prior to the formation of the canyonlands.

Dust and molecules in extra-galactic planetary nebulae

NASA Astrophysics Data System (ADS)

Garcia-Hernandez, Domingo Aníbal

2015-08-01

Extra-galactic planetary nebulae (PNe) permit the study of dust and molecules in metallicity environments other than the Galaxy. Their known distances lower the number of free parameters in the observations vs. models comparison, providing strong constraints on the gas-phase and solid-state astrochemistry models. Observations of PNe in the Galaxy and other Local Group galaxies such as the Magellanic Clouds (MC) provide evidence that metallicity affects the production of dust as well as the formation of complex organic molecules and inorganic solid-state compounds in their circumstellar envelopes. In particular, the lower metallicity MC environments seem to be less favorable to dust production and the frequency of carbonaceous dust features and complex fullerene molecules is generally higher with decreasing metallicity. Here, I present an observational review of the dust and molecular content in extra-galactic PNe as compared to their higher metallicity Galactic counterparts. A special attention is given to the level of dust processing and the formation of complex organic molecules (e.g., polycyclic aromatic hydrocarbons, fullerenes, and graphene precursors) depending on metallicity.

Powder metallurgy of Ge, Si, and Ge-Si

NASA Astrophysics Data System (ADS)

Schilz, Jürgen; Langenbach, Marion

1993-03-01

id="ab1"Planetary ball-milling and pressing behaviour of Ge, Si and Ge-Si powder mixtures are investigated. Scanning and transmission electron microscopy observations revealed the different microstructure of the two elements after milling: Ge remains in a microcrystalline state, whereas Si can be comminuted into grains consisting of nanocrystalline regions. Planetary milling of the two elements together, using agate balls and vial, did not reveal any compound formation. By hot-isostatic pressing, pure Ge and Ge-Si mixtures were densified to a higher value than pure Si. This denotes a plastic flow of the Ge component at a process temperature of 800°C. The microhardness of hot-pressed Ge reaches the bulk value; hot-pressed Si is very soft. Energy dispersive X-ray analysis and X-ray diffraction did not detect any impurity contamination from vial and milling media wear. Moreover, by electrical transport measurements it turned out that the net carrier concentration density resulting from electrical active impurities introduced by the milling and pressing process is below 2 x 1016 cm 3 at room temperature.

Prebiotic hydrocarbon synthesis in impacting reduced astrophysical icy mixtures

DOE PAGES

Koziol, Lucas; Goldman, Nir

2015-04-21

We present results of prebiotic organic synthesis in shock-compressed reducing mixtures of simple ices from quantum molecular dynamics simulations extended to close to chemical equilibrium timescales. Given the relative abundance of carbon in reduced forms in astrophysical ices as well as the tendency of these mixtures to form complex hydrocarbons under the presence of external stimuli, it is possible that cometary impacts on a planetary surface could have yielded a larger array of prebiotic organic compounds than previously investigated. We find that the high pressures and temperatures due to shock compression yield a large assortment of carbon- and nitrogen-bonded extendedmore » structures that are highly reactive with short molecular lifetimes. Expansion and cooling causes these materials to break apart and form a wide variety of stable, potentially life-building compounds, including long-chain linear and branched hydrocarbons, large heterocyclic compounds, and a variety of different amines and exotic amino acids. Lastly, our results help provide a bottom-up understanding of hydrocarbon impact synthesis on the early Earth and its role in producing life-building molecules from simple starting materials.« less

Prebiotic hydrocarbon synthesis in impacting reduced astrophysical icy mixtures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koziol, Lucas; Goldman, Nir

We present results of prebiotic organic synthesis in shock-compressed reducing mixtures of simple ices from quantum molecular dynamics simulations extended to close to chemical equilibrium timescales. Given the relative abundance of carbon in reduced forms in astrophysical ices as well as the tendency of these mixtures to form complex hydrocarbons under the presence of external stimuli, it is possible that cometary impacts on a planetary surface could have yielded a larger array of prebiotic organic compounds than previously investigated. We find that the high pressures and temperatures due to shock compression yield a large assortment of carbon- and nitrogen-bonded extendedmore » structures that are highly reactive with short molecular lifetimes. Expansion and cooling causes these materials to break apart and form a wide variety of stable, potentially life-building compounds, including long-chain linear and branched hydrocarbons, large heterocyclic compounds, and a variety of different amines and exotic amino acids. Lastly, our results help provide a bottom-up understanding of hydrocarbon impact synthesis on the early Earth and its role in producing life-building molecules from simple starting materials.« less

Serpentinization and the Formation of H2 and CH4 on Celestial Bodies (Planets, Moons, Comets).

PubMed

Holm, N G; Oze, C; Mousis, O; Waite, J H; Guilbert-Lepoutre, A

2015-07-01

Serpentinization involves the hydrolysis and transformation of primary ferromagnesian minerals such as olivine ((Mg,Fe)2SiO4) and pyroxenes ((Mg,Fe)SiO3) to produce H2-rich fluids and a variety of secondary minerals over a wide range of environmental conditions. The continual and elevated production of H2 is capable of reducing carbon, thus initiating an inorganic pathway to produce organic compounds. The production of H2 and H2-dependent CH4 in serpentinization systems has received significant interdisciplinary interest, especially with regard to the abiotic synthesis of organic compounds and the origins and maintenance of life in Earth's lithosphere and elsewhere in the Universe. Here, serpentinization with an emphasis on the formation of H2 and CH4 are reviewed within the context of the mineralogy, temperature/pressure, and fluid/gas chemistry present in planetary environments. Whether deep in Earth's interior or in Kuiper Belt Objects in space, serpentinization is a feasible process to invoke as a means of producing astrobiologically indispensable H2 capable of reducing carbon to organic compounds.

A SAW-based chemical sensor for detecting sulfur-containing organophosphorus compounds using a two-step self-assembly and molecular imprinting technology.

PubMed

Pan, Yong; Yang, Liu; Mu, Ning; Shao, Shengyu; Wang, Wen; Xie, Xiao; He, Shitang

2014-05-19

This paper presents a new effective approach for the sensitive film deposition of surface acoustic wave (SAW) chemical sensors for detecting organophosphorus compounds such as O-ethyl-S-2-diisopropylaminoethyl methylphosphonothiolate (VX) containing sulfur at extremely low concentrations. To improve the adsorptive efficiency, a two-step technology is proposed for the sensitive film preparation on the SAW delay line utilizing gold electrodes. First, mono[6-deoxy-6-[(mercaptodecamethylene)thio

A SAW-Based Chemical Sensor for Detecting Sulfur-Containing Organophosphorus Compounds Using a Two-Step Self-Assembly and Molecular Imprinting Technology

PubMed Central

Pan, Yong; Yang, Liu; Mu, Ning; Shao, Shengyu; Wang, Wen; Xie, Xiao; He, Shitang

2014-01-01

This paper presents a new effective approach for the sensitive film deposition of surface acoustic wave (SAW) chemical sensors for detecting organophosphorus compounds such as O-ethyl-S-2-diisopropylaminoethyl methylphosphonothiolate (VX) containing sulfur at extremely low concentrations. To improve the adsorptive efficiency, a two-step technology is proposed for the sensitive film preparation on the SAW delay line utilizing gold electrodes. First, mono[6-deoxy-6-[(mercaptodecamethylene)thio

Highly stable meteoritic organic compounds as markers of asteroidal delivery

NASA Astrophysics Data System (ADS)

Cooper, George; Horz, Friedrich; Spees, Alanna; Chang, Sherwood

2014-01-01

Multiple missions to search for water-soluble organic compounds on the surfaces of Solar System bodies are either current or planned and, if such compounds were found, it would be desirable to determine their origin(s). Asteroid or comet material is likely to have been components of all surface environments throughout Solar System history. To simulate the survival of meteoritic compounds both during impacts with planetary surfaces and under subsequent (possibly) harsh ambient conditions, we subjected known meteoritic compounds to comparatively high impact-shock pressures (>30 GPa) and/or to extremely oxidizing/corrosive acid solution. Consistent with past impact experiments, α-amino acids survived only at trace levels above ∼18 GPa. Polyaromatic hydrocarbons (PAHs) survived at levels of 4-8% at a shock pressure of 36 GPa. Lower molecular weight sulfonic and phosphonic acids (S&P) had the highest degree of impact survival of all tested compounds at higher pressures. Oxidation of compounds was done with a 3:1 mixture of HCl:HNO3, a solution that generates additional strong oxidants such as Cl2 and NOCl. Upon oxidation, keto acids and α-amino acids were the most labile compounds with proline as a significant exception. Some fraction of the other compounds, including non-α amino acids and dicarboxylic acids, were stable during 16-18 hours of oxidation. However, S&P quantitatively survived several months (at least) under the same conditions. Such results begin to build a profile of the more robust meteoritic compounds: those that may have survived, i.e., may be found in, the more hostile Solar System environments. In the search for organic compounds, one current mission, NASA's Mars Science Laboratory (MSL), will use analytical procedures similar to those of this study and those employed previously on Earth to identify many of the compounds described in this work. The current results may thus prove to be directly relevant to potential findings of MSL and other missions designed for extraterrestrial organic analysis.

The Twenty-Fifth Lunar and Planetary Science Conference. Part 1: A-G

NASA Technical Reports Server (NTRS)

1994-01-01

Papers from the conference are presented, and the topics covered include the following: planetary geology, meteorites, planetary composition, meteoritic composition, planetary craters, lunar craters, meteorite craters, petrology, petrography, volcanology, planetary crusts, geochronology, geomorphism, mineralogy, lithology, planetary atmospheres, impact melts, volcanoes, planetary evolution, tectonics, planetary mapping, asteroids, comets, lunar soil, lunar rocks, lunar geology, metamorphism, chemical composition, meteorite craters, and planetary mantles.

Origin of the Reflectin Gene and Hierarchical Assembly of Its Protein.

PubMed

Guan, Zhe; Cai, Tiantian; Liu, Zhongmin; Dou, Yunfeng; Hu, Xuesong; Zhang, Peng; Sun, Xin; Li, Hongwei; Kuang, Yao; Zhai, Qiran; Ruan, Hao; Li, Xuanxuan; Li, Zeyang; Zhu, Qihui; Mai, Jingeng; Wang, Qining; Lai, Luhua; Ji, Jianguo; Liu, Haiguang; Xia, Bin; Jiang, Taijiao; Luo, Shu-Jin; Wang, Hong-Wei; Xie, Can

2017-09-25

Cephalopods, the group of animals including octopus, squid, and cuttlefish, have remarkable ability to instantly modulate body coloration and patterns so as to blend into surrounding environments [1, 2] or send warning signals to other animals [3]. Reflectin is expressed exclusively in cephalopods, filling the lamellae of intracellular Bragg reflectors that exhibit dynamic iridescence and structural color change [4]. Here, we trace the possible origin of the reflectin gene back to a transposon from the symbiotic bioluminescent bacterium Vibrio fischeri and report the hierarchical structural architecture of reflectin protein. Intrinsic self-assembly, and higher-order assembly tightly modulated by aromatic compounds, provide insights into the formation of multilayer reflectors in iridophores and spherical microparticles in leucophores and may form the basis of structural color change in cephalopods. Self-assembly and higher-order assembly in reflectin originated from a core repeating octapeptide (here named protopeptide), which may be from the same symbiotic bacteria. The origin of the reflectin gene and assembly features of reflectin protein are of considerable biological interest. The hierarchical structural architecture of reflectin and its domain and protopeptide not only provide insights for bioinspired photonic materials but also serve as unique "assembly tags" and feasible molecular platforms in biotechnology. Copyright © 2017 Elsevier Ltd. All rights reserved.

Urey onboard Exomars: Searching for life on Mars

NASA Astrophysics Data System (ADS)

Bada, J.; Ehrenfreund, P.; Grunthaner, F.; Sephton, M.; Urey Team

2009-04-01

Exomars is currently under development as the flagship mission of ESA's exploration program Aurora. A fundamental challenge ahead for the Exomars mission is to search for extinct and extant life. The Urey instrument (Mars Organic and Oxidant Detector) has been selected for the Pasteur payload and is considered a key instrument to achieve the mission's scientific objectives. Urey can detect organic compounds at unprecedented sensitivity of part-per-trillions in the Martian regolith. The instrument will target several key classes of organic molecules such as amino acids, nucleobases, amines and amino sugars and polycyclic aromatic hydrocrabon (PAHs) using state-of-the-art analytical methods. Chemoresistor oxidant sensors will provide complementary measurements by simultaneously evaluating the survival potential of organic compounds in the environment. The Urey instrument concept has tremendous future applications in Mars and Moon exploration in the framework of life detection and planetary protection.

Molecular processes from the AGB to the PN stage

NASA Astrophysics Data System (ADS)

García-Hernández, D. Anibal

2012-08-01

Many complex organic molecules and inorganic solid-state compounds have been observed in the circumstellar shell of stars (both C-rich and O-rich) in the transition phase between Asymptotic Giant Branch (AGB) stars and Planetary Nebulae (PNe). This short (~102-104 years) phase of stellar evolution represents a wonderful laboratory for astrochemistry and provides severe constraints on any model of gas-phase and solid-state chemistry. One of the major challenges of present day astrophysics and astrochemistry is to understand the formation pathways of these complex organic molecules and inorganic solid-state compounds (e.g., polycyclic aromatic hydrocarbons, fullerenes, and graphene in the case of a C-rich chemistry and oxides and crystalline silicates in O-rich environments) in space. In this review, I present an observational review of the molecular processes in the late stages of stellar evolution with a special emphasis on the first detections of fullerenes and graphene in PNe.

Carbon Monoxide and the Potential for Prebiotic Chemistry on Habitable Planets Around Main Sequence M Stars

NASA Technical Reports Server (NTRS)

Nava-Sedeno, J. Manik; Ortiz-Cervantes, Adrian; Segura, Antigona; Domagal-Goldman, Shawn D.

2016-01-01

Lifeless planets with CO2 atmospheres produce CO by CO2 photolysis. On planets around M dwarfs, CO is a long-lived atmospheric compound, as long as UV emission due to the stars chromospheric activity lasts, and the sink of CO and O2 in seawater is small compared to its atmospheric production. Atmospheres containing reduced compounds, like CO, may undergo further energetic and chemical processing to give rise to organic compounds of potential importance for the origin of life. We calculated the yield of organic compounds from CO2-rich atmospheres of planets orbiting M dwarf stars, which were previously simulated by Domagal- Goldman et al. (2014) and Harman et al. (2015), by cosmic rays and lightning using results of experiments by Miyakawaet al. (2002) and Schlesinger and Miller (1983a, 1983b). Stellar protons from active stars may be important energy sources for abiotic synthesis and increase production rates of biological compounds by at least 2 orders of magnitude compared to cosmic rays. Simple compounds such as HCN and H2CO are more readily synthesized than more complex ones, such as amino acids and uracil (considered here as an example), resulting in higher yields for the former and lower yields for the latter. Electric discharges are most efficient when a reducing atmosphere is present. Nonetheless, atmospheres with high quantities of CO2 are capable of producing higher amounts of prebiotic compounds, given that CO is constantly produced in the atmosphere. Our results further support planetary systems around M dwarf stars as candidates for supporting life or its origin.

Performance of The Far Ultraviolet Spectroscopic Explorer Mirror Assemblies

NASA Technical Reports Server (NTRS)

Ohi, Raymond G.; Barkhouser, Robert H.; Conard, Steven J.; Friedman, Scott D.; Hampton, Jeffery; Moos, H. Warren; Nikulla, Paul; Oliveira, Cristina M.; Saha, Timo T.; Obenschain, Arthur (Technical Monitor)

2000-01-01

The Far Ultraviolet Spectroscopic Explorer is a NASA astrophysics satellite which produces high-resolution spectra in the far-ultraviolet (90.5-118.7 nm bandpass) using a high effective area and low background detectors. The observatory was launched on its three-year mission from Cape Canaveral Air Station on 24 June 1999. The instrument contains four coaligned, normal incidence, off-axis parabolic mirrors which illuminate separate Rowland circle spectrograph channels equipped with holographically ruled diffraction gratings and delay line microchannel plate detectors. The telescope mirrors have a 352 x 387 mm aperture and 2245 mm focal length and are attached to actuator assemblies, which provide on-orbit, tip, tilt, and focus control. Two mirrors are coated with silicon carbide (SiC) and two are coated with lithium fluoride over aluminum (Al:LiF). We describe mirror assembly in-flight optical and mechanical performance. On-orbit measurements of the far-ultraviolet point spread function associated with each mirror are compared to expectations based on pre-flight laboratory measurements and modeling using the Optical Surface Analysis Code and surface metrology data. On-orbit imaging data indicate that the mirrors meet their instrument-level requirement of 50 percent and 95 percent slit transmission for the high- and mid-resolution spectrograph entrance slits, respectively. The degradation of mirror reflectivity during satellite integration and test is also discussed. The far-ultraviolet reflectivity of the SiC- and AlLiF-coated mirrors decreased about six percent and three percent, respectively, between coating and launch. Each mirror is equipped with three actuators, which consist of a stepper motor driving a ball screw via a two-stage planetary gear train. We also discuss the mechanical performance of the mirror assemblies, including actuator performance and thermal effects.

Performance of the Far Ultraviolet Spectroscopic Explorer mirror assemblies

NASA Astrophysics Data System (ADS)

Ohl, Raymond G.; Barkhouser, Robert H.; Conard, Steven J.; Friedman, Scott D.; Hampton, Jeffrey; Moos, H. Warren; Nikulla, Paul; Oliveira, Cristina M.; Saha, Timo T.

2000-12-01

The Far Ultraviolet Spectroscopic Explorer is a NASA astrophysics satellite which produces high-resolution spectra in the far-ultraviolet (90.5 - 118.7 nm bandpass) using a high effective area and low background detectors. The observatory was launched on its three-year mission from Cape Canaveral Air Station on 24 June 1999. The instrument contains four co- aligned, normal incidence, off-axis parabolic mirrors which illuminate separate Rowland circle spectrograph channels equipped with holographically ruled diffraction gratings and delay line microchannel plate detectors. The telescope mirrors have a 352 X 387 mm aperture and 2245 mm focal length and are attached to actuator assemblies, which provide on-orbit, tip, tilt, and focus control. Two mirrors are coated with silicon carbide (SiC) and two are coated with lithium fluoride over aluminum (Al:LiF). We describe mirror assembly in-flight optical and mechanical performance. On-orbit measurements of the far-ultraviolet point spread function associated with each mirror are compared to expectations based on pre-flight laboratory measurements and modeling using the Optical Surface Analysis Code and surface metrology data. On-orbit imaging data indicate that the mirrors meet their instrument-level requirement of 50% and 95% slit transmission for the high- and mid-resolution spectrograph entrance slits, respectively. The degradation of mirror reflectivity during satellite integration and test is also discussed. The FUV reflectivity of the SiC- and Al:LiF-coated mirrors decreased about 6% and 3%, respectively, between coating and launch. Each mirror is equipped with three actuators, which consist of a stepper motor driving a ball screw via a two-stage planetary gear train. We also discuss the mechanical performance of the mirror assemblies, including actuator performance and thermal effects.

Twenty-Fourth Lunar and Planetary Science Conference. Part 2: G-M

NASA Technical Reports Server (NTRS)

1993-01-01

The topics covered include the following: meteorites, meteoritic composition, geochemistry, planetary geology, planetary composition, planetary craters, the Moon, Mars, Venus, asteroids, planetary atmospheres, meteorite craters, space exploration, lunar geology, planetary surfaces, lunar surface, lunar rocks, lunar soil, planetary atmospheres, lunar atmosphere, lunar exploration, space missions, geomorphology, lithology, petrology, petrography, planetary evolution, Earth surface, planetary surfaces, volcanology, volcanos, lava, magma, mineralogy, minerals, ejecta, impact damage, meteoritic damage, tectonics, etc.

Twenty-Fourth Lunar and Planetary Science Conference. Part 3: N-Z

NASA Technical Reports Server (NTRS)

1993-01-01

Papers from the conference are presented, and the topics covered include the following: planetary geology, meteorites, planetary composition, meteoritic composition, planetary craters, lunar craters, meteorite craters, petrology, petrography, volcanology, planetary crusts, geochronology, geomorphism, mineralogy, lithology, planetary atmospheres, impact melts, K-T Boundary Layer, volcanoes, planetary evolution, tectonics, planetary mapping, asteroids, comets, lunar soil, lunar rocks, lunar geology, metamorphism, chemical composition, meteorite craters, planetary mantles, and space exploration.

A preliminary structural analysis of space-based inflatable tubular frame structures

NASA Technical Reports Server (NTRS)

Main, John A.; Peterson, Steven W.; Strauss, Alvin M.

1992-01-01

The use of inflatable structures has often been proposed for aerospace and planetary applications. The advantages of such structures include low launch weight and easy assembly. The use of inflatables for applications requiring very large frame structures intended for aerospace use are proposed. In order to consider using an inflated truss, the structural behavior of the inflated frame must be examined. The statics of inflated tubes as beams was discussed in the literature, but the dynamics of these elements has not received much attention. In an effort to evaluate the vibration characteristics of the inflated beam a series of free vibration tests of an inflated fabric cantilevers were performed. Results of the tests are presented and models for system behavior posed.

Space Telescope maintenance and refurbishment

NASA Technical Reports Server (NTRS)

Trucks, H. F.

1983-01-01

The Space Telescope (ST) represents a new concept regarding spaceborne astronomical observatories. Maintenance crews will be brought to the orbital worksite to make repairs and replace scientific instruments. For major overhauls the telescope can be temporarily returned to earth with the aid of the Shuttle. It will, thus, be possible to conduct astronomical studies with the ST for two decades or more. The five first-generation scientific instruments used with the ST include a wide field/planetary camera, a faint object camera, a faint object spectrograph, a high resolution spectrograph, and a high speed photometer. Attention is given to the optical telescope assembly, the support systems module, aspects of mission and science operations, unscheduled maintenance, contingency orbital maintenance, planned on-orbit maintenance, ground maintenance, ground refurbishment, and ground logistics.

Deuterium microbomb rocket propulsion

NASA Astrophysics Data System (ADS)

Winterberg, F.

2010-01-01

Large scale manned space flight within the solar system is still confronted with the solution of two problems: (1) A propulsion system to transport large payloads with short transit times between different planetary orbits. (2) A cost effective lifting of large payloads into earth orbit. For the solution of the first problem a deuterium fusion bomb propulsion system is proposed where a thermonuclear detonation wave is ignited in a small cylindrical assembly of deuterium with a gigavolt-multimegaampere proton beam, drawn from the magnetically insulated spacecraft acting in the ultrahigh vacuum of space as a gigavolt capacitor. For the solution of the second problem, the ignition is done by argon ion lasers driven by high explosives, with the lasers destroyed in the fusion explosion and becoming part of the exhaust.

Geologic map of the MTM 25047 and 20047 quadrangles, central Chryse Planitia/Viking 1 Lander site, Mars

USGS Publications Warehouse

Crumpler, L.S.; Craddock, R.A.; Aubele, J.C.

2001-01-01

This map uses Viking Orbiter image data and Viking 1 Lander image data to evaluate the geologic history of a part of Chryse Planitia, Mars. The map area lies at the termini of the Maja and Kasei Valles outwash channels and includes the site of the Viking 1 Lander. The photomosaic base for these quadrangles was assembled from 98 Viking Orbiter frames comprising 1204 pixels per line and 1056 lines and ranging in resolution from 20 to 200 m/pixel. These orbital image data were supplemented with images of the surface as seen from the Viking 1 Lander, one of only three sites on the martian surface where planetary geologic mapping is assisted by ground truth.

Noble gas storage and delivery system for ion propulsion

NASA Technical Reports Server (NTRS)

Back, Dwight Douglas (Inventor); Ramos, Charlie (Inventor)

2001-01-01

A method and system for storing and delivering a noble gas for an ion propulsion system where an adsorbent bearing a noble gas is heated within a storage vessel to desorb the noble gas which is then flowed through a pressure reduction device to a thruster assembly. The pressure and flow is controlled using a flow restrictor and low wattage heater which heats an adsorbent bed containing the noble gas propellant at low pressures. Flow rates of 5-60 sccm can be controlled to within about 0.5% or less and the required input power is generally less than 50 W. This noble gas storage and delivery system and method can be used for earth orbit satellites, and lunar or planetary space missions.

Development of a Linear Ion Trap Mass Spectrometer (LITMS) Investigation for Future Planetary Surface Missions

NASA Technical Reports Server (NTRS)

Brinckerhoff, W.; Danell, R.; Van Ameron, F.; Pinnick, V.; Li, X.; Arevalo, R.; Glavin, D.; Getty, S.; Mahaffy, P.; Chu, P.;

Detecting Nonvolatile Life- and Nonlife-Derived Organics in a Carbonaceous Chondrite Analogue with a New Multiplex Immunoassay and Its Relevance for Planetary Exploration.

PubMed

Moreno-Paz, Mercedes; Gómez-Cifuentes, Ana; Ruiz-Bermejo, Marta; Hofstetter, Oliver; Maquieira, Ángel; Manchado, Juan M; Morais, Sergi; Sephton, Mark A; Niessner, Reinhard; Knopp, Dietmar; Parro, Victor

2018-04-11

Potential martian molecular targets include those supplied by meteoritic carbonaceous chondrites such as amino acids and polycyclic aromatic hydrocarbons and true biomarkers stemming from any hypothetical martian biota (organic architectures that can be directly related to once living organisms). Heat extraction and pyrolysis-based methods currently used in planetary exploration are highly aggressive and very often modify the target molecules making their identification a cumbersome task. We have developed and validated a mild, nondestructive, multiplex inhibitory microarray immunoassay and demonstrated its implementation in the SOLID (Signs of Life Detector) instrument for simultaneous detection of several nonvolatile life- and nonlife-derived organic molecules relevant in planetary exploration and environmental monitoring. By utilizing a set of highly specific antibodies that recognize D- or L- aromatic amino acids (Phe, Tyr, Trp), benzo[a]pyrene (B[a]P), pentachlorophenol, and sulfone-containing aromatic compounds, respectively, the assay was validated in the SOLID instrument for the analysis of carbon-rich samples used as analogues of the organic material in carbonaceous chondrites or even Mars samples. Most of the antibodies enabled sensitivities at the 1-10 ppb level and some even at the ppt level. The multiplex immunoassay allowed the detection of B[a]P as well as aromatic sulfones in a water/methanol extract of an Early Cretaceous lignite sample (c.a., 140 Ma) representing type IV kerogen. No L- or D-aromatic amino acids were detected, reflecting the advanced diagenetic stage and the fossil nature of the sample. The results demonstrate the ability of the liquid extraction by ultrasonication and the versatility of the multiplex inhibitory immunoassays in the SOLID instrument to discriminate between organic matter derived from life and nonlife processes, an essential step toward life detection outside Earth. Key Words: Planetary exploration-Molecular biomarkers-D- and L- aromatic amino acids-Life detection-Multiplex inhibitory/competitive immunoassay-Kerogen type IV. Astrobiology 18, xxx-xxx.

Efficient Syntheses of Organics and Nanomaterials Using Microwaves

EPA Science Inventory

A brief account of reactions involving microwave (MW) exposure of neat reactants or catalyzed by mineral support surfaces, such as alumina, silica, clay, or their ‘doped’ versions, for the rapid one-pot assembly of heterocyclic compounds from in situ generated reactive intermedia...

Green Synthetic Alternatives to Organic Molecules and Nanomaterials

EPA Science Inventory

A brief account of reactions involving microwave (MW) exposure of neat reactants or catalyzed by mineral support surfaces, such as alumina, silica, clay, or their ‘doped’ versions, for the rapid one-pot assembly of heterocyclic compounds from in situ generated reactive intermedia...

Greener Synthetic Alternatives to Organic Molecules and Nanomaterials

EPA Science Inventory

A brief account of reactions involving microwave (MW) exposure of neat reactants or catalyzed by mineral support surfaces, such as alumina, silica, clay, or their ‘doped’ versions, for the rapid one-pot assembly of heterocyclic compounds from in situ generated reactive intermedia...

DEMONSTRATION BULLETIN: LOW TEMPERATURE THERMAL TREATMENT (LT3®) SYSTEM

EPA Science Inventory

The Roy F. Weston, Inc. (Weston) low temperature thermal treatment (LT³®) system thermally desorbs organic compounds from contaminated soil without heating the soil to combustion temperatures. The transportable system is comprised of equipment assembled on thre...

Greener Synthetic Alternatives to Heterocycles, Nanomaterials and Nanocomposites

EPA Science Inventory

Microwave (MW) expedited reaction of neat reactants or catalyzed by mineral support surfaces, such as alumina, silica, clay, or their ‘doped’ versions, for the rapid one-pot assembly of heterocyclic compounds from in situ generated reactive intermediates via enamines or using hyp...

Surface Confined Metallosupramolecular Architectures: Formation and STM Characterization

PubMed Central

Li, Shan-Shan; Northrop, Brian H.; Yuan, Qun-Hui; Wan, Li-Jun; Stang, Peter J.

2009-01-01

CONSPECTUS Metallosupramolecular compounds have attracted a great deal of attention over the past two decades largely because of their unique, highly-complex structural characteristics, the fact that they can be prepared with relative ease using coordination-driven self-assembly techniques, and their potential electronic, magnetic, optical, and catalytic properties. In particular, the use of electron-poor square planar Pt(II) transition metals in conjunction with rigid, electron-rich pyridyl donors had enabled the spontaneous self-assembly of a rich library of 2D metallacyclic and 3D metallacage assemblies via the directional-bonding approach. With the tremendous progress that has been made in the preparation and characterization of metallosupramolecules, much attention is now being turned toward fully exploring and developing their materials properties. Assembling metallosupramolecular compounds on solid supports represents a vitally important step toward developing their materials properties. Surfaces provide a means of uniformly aligning and orienting these highly symmetric metallacycles and metallacages, which increases the level of coherence between molecules above that which can be achieved in the solution phase and affords a means of integrating adlayers into a solid-state materials setting. The dynamic nature of kinetically labile Pt(II)-N coordination bonds, however, requires that deposition and imaging conditions be appropriate to retain the assemblies' stability. Toward these aims it is imperative to understand the factors that govern surface self-assembly and the interactions that influence the structure and stability of the resulting adlayer. Such insight can be obtained from Scanning Tunneling Microscopy (STM), which has emerged as a powerful technique for the imaging and characterization of self-assembled adlayers. This account describes the means by which 2D rectangular and square metallacycles and 3D trigonal bipyrimidal and chiral trigonal prism metallacages can be deposited on Highly Oriented Pyrolytic Graphite (HOPG) and Au(111) substrates such that the assemblies remain intact and result in ordered adlayers. The effects of varying the size, symmetry, and dimensionality of supramolecular adsorbates, the choice of substrate, the use of a molecular template, and the effects of chirality have been investigated. These systematic investigations provide much insight into the various adsorbate-adsorbate and substrate-adsorbate interactions that largely determine the architecture of each assembly and affect their performance in a materials setting. Exhibiting the ability to rationally control adlayer formation and structure will greatly enhance the potential of these supramolecules to be used in a variety of applications such as in host-guest sensing/diagnostic systems, molecular electronic devices, and in heterogeneous stereoselective synthesis and catalysis. PMID:19072706

Three-dimensional aromatic networks.

PubMed

Toyota, Shinji; Iwanaga, Tetsuo

2014-01-01

Three-dimensional (3D) networks consisting of aromatic units and linkers are reviewed from various aspects. To understand principles for the construction of such compounds, we generalize the roles of building units, the synthetic approaches, and the classification of networks. As fundamental compounds, cyclophanes with large aromatic units and aromatic macrocycles with linear acetylene linkers are highlighted in terms of transannular interactions between aromatic units, conformational preference, and resolution of chiral derivatives. Polycyclic cage compounds are constructed from building units by linkages via covalent bonds, metal-coordination bonds, or hydrogen bonds. Large cage networks often include a wide range of guest species in their cavity to afford novel inclusion compounds. Topological isomers consisting of two or more macrocycles are formed by cyclization of preorganized species. Some complicated topological networks are constructed by self-assembly of simple building units.

Recent developments on dry eye disease treatment compounds.

PubMed

Colligris, Basilio; Alkozi, Hanan Awad; Pintor, Jesus

2014-01-01

Dry eye syndrome is a common tears and ocular surface multifactorial disease, described by changes in the ocular surface epithelia related to reduced tears quantity and ocular surface sensitivity, leading to inflammatory reaction. Managing the eye inflammation proved helpful to patients with dry eye disease and current treatment is based on the use of topically applied artificial tear products/lubricants, tear retention management, stimulation of tear secretion and using anti-inflammatory drugs. In this article we revise the corresponding literature and patents assembling the new treatment approaches of novel and future pharmaceutical compounds destined for the dry eye disease treatment. The most frequent categories of compounds presented are secretagogues and anti-inflammatory drugs. These compounds are the research outcome of novel therapeutic strategies designed to reduce key inflammatory pathways and restore healthy tear film.

Aligned and Electrospun Piezoelectric Polymer Fiber Assembly and Scaffold

NASA Technical Reports Server (NTRS)

Holloway, Nancy M. (Inventor); Scott-Carnell, Lisa A. (Inventor); Siochi, Emilie J. (Inventor); Leong, Kam W. (Inventor); Kulangara, Karina (Inventor)

2015-01-01

A scaffold assembly and related methods of manufacturing and/or using the scaffold for stem cell culture and tissue engineering applications are disclosed which at least partially mimic a native biological environment by providing biochemical, topographical, mechanical and electrical cues by using an electroactive material. The assembly includes at least one layer of substantially aligned, electrospun polymer fiber having an operative connection for individual voltage application. A method of cell tissue engineering and/or stem cell differentiation uses the assembly seeded with a sample of cells suspended in cell culture media, incubates and applies voltage to one or more layers, and thus produces cells and/or a tissue construct. In another aspect, the invention provides a method of manufacturing the assembly including the steps of providing a first pre-electroded substrate surface; electrospinning a first substantially aligned polymer fiber layer onto the first surface; providing a second pre-electroded substrate surface; electrospinning a second substantially aligned polymer fiber layer onto the second surface; and, retaining together the layered surfaces with a clamp and/or an adhesive compound.

Aligned and Electrospun Piezoelectric Polymer Fiber Assembly and Scaffold

NASA Technical Reports Server (NTRS)

Kulangara, Karina (Inventor); Scott Carnell, Lisa A. (Inventor); Holloway, Nancy M. (Inventor); Leong, Kam W. (Inventor); Siochi, Emilie J. (Inventor)

2017-01-01

A method of manufacturing and/or using a scaffold assembly for stem cell culture and tissue engineering applications is disclosed. The scaffold at least partially mimics a native biological environment by providing biochemical, topographical, mechanical and electrical cues by using an electroactive material. The assembly includes at least one layer of substantially aligned, electrospun polymer fiber having an operative connection for individual voltage application. A method of cell tissue engineering and/or stem cell differentiation that uses the assembly seeded with a sample of cells suspended in cell culture media, incubates and applies voltage to one or more layers, and thus produces cells and/or a tissue construct. In another aspect, the invention provides a method of manufacturing the assembly including the steps of providing a first pre-electroded substrate surface; electrospinning a first substantially aligned polymer fiber layer onto the first surface; providing a second pre-electroded substrate surface; electrospinning a second substantially aligned polymer fiber layer onto the second surface; and, retaining together the layered surfaces with a clamp and/or an adhesive compound.

Three-dimensional six-connecting organic building blocks based on polychlorotriphenylmethyl units--synthesis, self-assembly, and magnetic properties.

PubMed

Roques, Nans; Maspoch, Daniel; Wurst, Klaus; Ruiz-Molina, Daniel; Rovira, Concepció; Veciana, Jaume

2006-12-13

The synthesis of a three-dimensional, six-connecting, organic building block based on a robust, rigid, and open-shell polychlorotriphenylmethyl (PTM) unit (radical 1) is reported, and its self-assembly properties are described in detail. The tendencies of this highly polar molecule and its hydrogenated precursor, compound 4, to form hydrogen bonds with oxygenated solvents ([1THF(6)] and [4THF(6)]) were reduced by replacing THF with diethyl ether in the crystallization process to yield two-dimensional (2D) hydrogen-bonded structures ([1(Et(2)O)(3)] and [4(Et(2)O)(3)]). The presence of direct hydrogen bonds between the radicals in the latter phase of 1 gives rise to very weak ferromagnetic intermolecular interactions at low temperatures, whereas when the radicals are isolated by THF molecules these interactions are antiferromagnetic and very weak. The role played by the carboxylic groups not only in the self-assembly properties but also in the transmission of the magnetic interactions has been illustrated by determination of the crystal structure and measurement of the magnetic properties of the corresponding hexaester radical 6, in which the close packing of molecular units gives rise to weak antiferromagnetic intermolecular interactions. Attempts to avoid solvation of the molecules in the solid state and to increase the structural and magnetic dimensionality were pursued by recrystallization of both compounds 1 and 4 from concentrated nitric acid, affording two three-dimensional (3D) robust hydrogen-bonded structures. While the structure obtained with compound 4 is characterized by the presence of polar channels and boxes containing water guest molecules along the c axis, radical 1 was oxidized to the corresponding fuchsone 10, which presented a completely different close-packed, guest-free structure.

Self-Assembled Pyridine-Dipyrrolate Cages.

PubMed

Zhang, Huacheng; Lee, Juhoon; Lammer, Aaron D; Chi, Xiaodong; Brewster, James T; Lynch, Vincent M; Li, Hao; Zhang, Zhan; Sessler, Jonathan L

2016-04-06

An inherently nonlinear pyridine dipyrrolate ligand, namely 2,6-bis(3,4-diethyl-5-carboxy-1H-pyrrol-2yl)pyridine (compound 1), is able to distinguish between different zinc(II) cation sources, namely Zn(acac)2 and Zn(OAc)2, respectively. This differentiation is manifest both in terms of the observed fluorescent behavior in mixed organic media and the reaction chemistry. Treatment of 1 with Zn(acac)2 gives rise to a cage dimer, cage-1, wherein two molecules of compound 1 act as double bridging units to connect two individual cage subunits. As inferred from X-ray crystallographic studies, this cage system consists of discrete zinc dimers with hydroxide bridges that, with the assistance of bound DMF solvent molecules, serve to fix the geometry and orientation of the pyridine dipyrrolate building blocks. When a different zinc source, Zn(OAc)2, is used to carry out an ostensibly similar complexation reaction with compound 1, an acetate-bridged 1D abacus-like cage polymer is obtained as inferred from X-ray diffraction analysis. This extended solid state structure, cage-2, contains individual zinc dimer cage submits and appears stabilized by solvent molecules (DMF) and the counteranion (acetate). Rod-like assemblies are also observed by DLS and SEM. This construct, in contrast to cage-1, proved fluorescent in mixed organic media. The structure of the ligand itself (i.e., in the absence of Zn(II)) was confirmed by X-ray crystallographic analysis and was found to assemble into a supramolecular polymer. Conversion to a dimer form was seen upon the addition of TBAOAc. On the basis of the metric parameters, the structures seen in the solid state are stabilized via hydrogen bonding interactions involving solvent molecules.

Screening Libraries of Semifluorinated Arylene Bisimides to Discover and Predict Thermodynamically Controlled Helical Crystallization.

PubMed

Ho, Ming-Shou; Partridge, Benjamin E; Sun, Hao-Jan; Sahoo, Dipankar; Leowanawat, Pawaret; Peterca, Mihai; Graf, Robert; Spiess, Hans W; Zeng, Xiangbing; Ungar, Goran; Heiney, Paul A; Hsu, Chain-Shu; Percec, Virgil

2016-12-12

Synthesis, structural, and retrostructural analysis of a library containing 16 self-assembling perylene (PBI), 1,6,7,12-tetrachloroperylene (Cl 4 PBI), naphthalene (NBI), and pyromellitic (PMBI) bisimides functionalized with environmentally friendly AB 3 chiral racemic semifluorinated minidendrons at their imide groups via m = 0, 1, 2, and 3 methylene units is reported. These semifluorinated compounds melt at lower temperatures than homologous hydrogenated compounds, permitting screening of all their thermotropic phases via structural analysis to discover thermodynamically controlled helical crystallization from propeller-like, cogwheel, and tilted molecules as well as lamellar-like structures. Thermodynamically controlled helical crystallization was discovered for propeller-like PBI, Cl 4 PBI and NBI with m = 0. Unexpectedly, assemblies of twisted Cl 4 PBIs exhibit higher order than those of planar PBIs. PBI with m = 1, 2, and 3 form a thermodynamically controlled columnar hexagonal 2D lattice of tilted helical columns with intracolumnar order. PBI and Cl 4 PBI with m = 1 crystallize via a recently discovered helical cogwheel mechanism, while NBI and PMBI with m = 1 form tilted helical columns. PBI, NBI and PMBI with m = 2 generate lamellar-like structures. 3D and 2D assemblies of PBI with m = 1, 2, and 3, NBI with m = 1 and PMBI with m = 2 exhibit 3.4 Å π-π stacking. The library approach applied here and in previous work enabled the discovery of six assemblies which self-organize via thermodynamic control into 3D and 2D periodic arrays, and provides molecular principles to predict the supramolecular structure of electronically active components.

Synthetic inhibitors of bacterial cell division targeting the GTP-binding site of FtsZ.

PubMed

Ruiz-Avila, Laura B; Huecas, Sonia; Artola, Marta; Vergoñós, Albert; Ramírez-Aportela, Erney; Cercenado, Emilia; Barasoain, Isabel; Vázquez-Villa, Henar; Martín-Fontecha, Mar; Chacón, Pablo; López-Rodríguez, María L; Andreu, José M

2013-09-20

Cell division protein FtsZ is the organizer of the cytokinetic Z-ring in most bacteria and a target for new antibiotics. FtsZ assembles with GTP into filaments that hydrolyze the nucleotide at the association interface between monomers and then disassemble. We have replaced FtsZ's GTP with non-nucleotide synthetic inhibitors of bacterial division. We searched for these small molecules among compounds from the literature, from virtual screening (VS), and from our in-house synthetic library (UCM), employing a fluorescence anisotropy primary assay. From these screens we have identified the polyhydroxy aromatic compound UCM05 and its simplified analogue UCM44 that specifically bind to Bacillus subtilis FtsZ monomers with micromolar affinities and perturb normal assembly, as examined with light scattering, polymer sedimentation, and negative stain electron microscopy. On the other hand, these ligands induce the cooperative assembly of nucleotide-devoid archaeal FtsZ into distinct well-ordered polymers, different from GTP-induced filaments. These FtsZ inhibitors impair localization of FtsZ into the Z-ring and inhibit bacterial cell division. The chlorinated analogue UCM53 inhibits the growth of clinical isolates of antibiotic-resistant Staphylococcus aureus and Enterococcus faecalis. We suggest that these interfacial inhibitors recapitulate binding and some assembly-inducing effects of GTP but impair the correct structural dynamics of FtsZ filaments and thus inhibit bacterial division, possibly by binding to a small fraction of the FtsZ molecules in a bacterial cell, which opens a new approach to FtsZ-based antibacterial drug discovery.

Quantification and characterization of volatiles evolved during extrusion of rice and soy flours.

PubMed

Vodovotz, Y; Zasypkin, D; Lertsiriyothin, W; Lee, T C; Bourland, C T

2000-01-01

NASA-Johnson Space Center is designing and building a habitat (Bioregenerative Planetary Life Support Systems Test Complex, BIO-Plex) intended for evaluating advanced life support systems developed for long-duration missions to the Moon or Mars where all consumables will be recycled and reused. A food system based on raw products obtained from higher plants (such as soybeans, rice, and wheat) may be a central feature of a biologically based Advanced Life Support System. To convert raw crops to edible ingredients or food items, multipurpose processing equipment such as an extruder is ideal. Volatile compounds evolved during the manufacturing of these food products may accumulate and reach toxic levels. Additionally, off-odors often dissipated in open-air environments without consequence may cause significant discomfort in the BIO-Plex. Rice and defatted soy flours were adjusted to 16% moisture, and triplicate samples were extruded using a tabletop single-screw extruder. The extrudate was collected in specially designed Tedlar bags from which air samples could be extracted. The samples were analyzed by GC-MS with special emphasis on compounds with Spacecraft Maximum Allowable Concentrations (SMACs). Results showed a combination of alcohols, aldehydes, ketones, and carbonyl compounds in the different flours. Each compound and its SMAC value, as well as its impact on the air revitalization system, was discussed.

Quantification and characterization of volatiles evolved during extrusion of rice and soy flours

NASA Technical Reports Server (NTRS)

Vodovotz, Y.; Zasypkin, D.; Lertsiriyothin, W.; Lee, T. C.; Bourland, C. T.

2000-01-01

NASA-Johnson Space Center is designing and building a habitat (Bioregenerative Planetary Life Support Systems Test Complex, BIO-Plex) intended for evaluating advanced life support systems developed for long-duration missions to the Moon or Mars where all consumables will be recycled and reused. A food system based on raw products obtained from higher plants (such as soybeans, rice, and wheat) may be a central feature of a biologically based Advanced Life Support System. To convert raw crops to edible ingredients or food items, multipurpose processing equipment such as an extruder is ideal. Volatile compounds evolved during the manufacturing of these food products may accumulate and reach toxic levels. Additionally, off-odors often dissipated in open-air environments without consequence may cause significant discomfort in the BIO-Plex. Rice and defatted soy flours were adjusted to 16% moisture, and triplicate samples were extruded using a tabletop single-screw extruder. The extrudate was collected in specially designed Tedlar bags from which air samples could be extracted. The samples were analyzed by GC-MS with special emphasis on compounds with Spacecraft Maximum Allowable Concentrations (SMACs). Results showed a combination of alcohols, aldehydes, ketones, and carbonyl compounds in the different flours. Each compound and its SMAC value, as well as its impact on the air revitalization system, was discussed.

A novel simplified model for torsional vibration analysis of a series-parallel hybrid electric vehicle

NASA Astrophysics Data System (ADS)

Tang, Xiaolin; Yang, Wei; Hu, Xiaosong; Zhang, Dejiu

2017-02-01

In this study, based on our previous work, a novel simplified torsional vibration dynamic model is established to study the torsional vibration characteristics of a compound planetary hybrid propulsion system. The main frequencies of the hybrid driveline are determined. In contrast to vibration characteristics of the previous 16-degree of freedom model, the simplified model can be used to accurately describe the low-frequency vibration property of this hybrid powertrain. This study provides a basis for further vibration control of the hybrid powertrain during the process of engine start/stop.

The Organic Content of the Tagish Lake Meteorite

NASA Technical Reports Server (NTRS)

Pizzarello, Sandra; Huang, Yongsong; Becker, Luann; Poreda, Robert J.; Nieman, Ronald A.; Cooper, George; Williams, Michael

2001-01-01

The Tagish Lake meteorite felt last year on a frozen take in Canada and may provide the most pristine material of its kind. Analyses have now shown this carbonaceous chondrite to contain a suite of soluble organic compounds (approximately 100 parts per million) that includes mono- and dicarboxylic acids, dicarboximides, pyridine carboxylic acids, a sulfonic acid, and both aliphatic and aromatic hydrocarbons. The insoluble carbon exhibits exclusive aromatic character, deuterium enrichment, and fullerenes containing 'planetary' helium and argon. The findings provide insight into an outcome of early solar chemical evolution that differs from any seen so far in meteorites.

Scientific guidelines for preservation of samples collected from Mars

NASA Technical Reports Server (NTRS)

Gooding, James L. (Editor)

1990-01-01

The maximum scientific value of Martian geologic and atmospheric samples is retained when the samples are preserved in the conditions that applied prior to their collection. Any sample degradation equates to loss of information. Based on detailed review of pertinent scientific literature, and advice from experts in planetary sample analysis, number values are recommended for key parameters in the environmental control of collected samples with respect to material contamination, temperature, head-space gas pressure, ionizing radiation, magnetic fields, and acceleration/shock. Parametric values recommended for the most sensitive geologic samples should also be adequate to preserve any biogenic compounds or exobiological relics.

Design of ferrocene-dipeptide bioorganometallic conjugates to induce chirality-organized structures.

PubMed

Moriuchi, Toshiyuki; Hirao, Toshikazu

2010-07-20

The highly ordered molecular assemblies in proteins can have a variety of functions, as observed in enzymes, receptors, and the like. Synthetic scientists are constructing bioinspired systems by harnessing the self-assembling properties of short peptides. Secondary structures such as alpha-helices, beta-sheets, and beta-turns are important in protein folding, which is mostly directed and stabilized by hydrogen bonding and the hydrophobic interactions of side chains. The design of secondary structure mimics that are composed of short peptides has attracted much attention, both for gaining fundamental insight into the factors affecting protein folding and for developing pharmacologically useful compounds, artificial receptors, asymmetric catalysts, and new materials. Ferrocenes are an organometallic scaffold with a central reverse-turn unit based on the inter-ring spacing of about 3.3 A, which is a suitable distance for hydrogen bonding between attached peptide strands. The conjugation of organometallic compounds with biomolecules such as amino acids, peptides, and DNA should provide novel systems that reflect properties of both the ferrocene and the biologically derived moieties. In this Account, we focus on recent advances in the design of ferrocene-peptide bioconjugates, which help illustrate the peptidomimetic basis for protein folding and the means of constructing highly ordered molecular assemblies. Ferrocene-peptide bioconjugates are constructed to form chirality-organized structures in both solid and solution states. The ferrocene serves as a reliable organometallic scaffold for the construction of protein secondary structures via intramolecular hydrogen bonding: the attached dipeptide strands are constrained within the appropriate dimensions. The introduction of the chiral dipeptide chains into the ferrocene scaffold induces the conformational enantiomerization of the ferrocenyl moiety; the chirality-organized structure results from intramolecular hydrogen bonding. The configuration and sequence of the amino acids are instrumental in the process. Regulation of the directionality and specificity of hydrogen bonding is a key component in the design of various molecular assemblies. Ferrocene-peptide bioconjugates also have a strong tendency to self-assemble through the contributions of available hydrogen-bonding donors in the solid state. Some ferrocene-peptide bioconjugates bearing only one dipeptide chain exhibit a helically ordered molecular assembly through a network of intermolecular (rather than intramolecular) hydrogen bonds. The propensity to form the chiral helicity appears to be controlled by the chirality of the dipeptide chains. Organization of host molecules is a useful strategy for forming artificial receptors. The conformationally regulated ferrocene-peptide bioconjugate provides the chirality-organized binding site for size-selective and chiral recognition of dicarboxylic acids through multipoint hydrogen bonds. Metal ions serve a variety of purposes in proteins, including structural stabilization for biological function. The complexation of ferrocene-peptide bioconjugates with palladium(II) compounds not only stabilizes the chirality conformational regulation but also induces conformational regulation of the dipeptide chain through complexation and intramolecular chirality organization. Construction of the chirality-organized ferrocene-peptide bioconjugates is also achieved by metal-directed assembly. These varied examples amply demonstrate the value of ferrocene-peptide bioconjugates in asserting architectural control over highly ordered molecular assemblies.

Twenty-Fourth Lunar and Planetary Science Conference. Part 2: G-M

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1993-01-01

The topics covered include the following: meteorites, meteoritic composition, geochemistry, planetary geology, planetary composition, planetary craters, the Moon, Mars, Venus, asteroids, planetary atmospheres, meteorite craters, space exploration, lunar geology, planetary surfaces, lunar surface, lunar rocks, lunar soil, planetary atmospheres, lunar atmosphere, lunar exploration, space missions, geomorphology, lithology, petrology, petrography, planetary evolution, Earth surface, planetary surfaces, volcanology, volcanos, lava, magma, mineralogy, minerals, ejecta, impact damage, meteoritic damage, tectonics, etc. Separate abstracts have been prepared for articles from this report.

Studies on the inhibition of tumor cell growth and microtubule assembly by 3-hydroxy-4-[(E)-(2-furyl)methylidene]methyl-3-cyclopentene-1,2-dione, an intensively coloured Maillard reaction product.

PubMed

Marko, D; Kemény, M; Bernady, E; Habermeyer, M; Weyand, U; Meiers, S; Frank, O; Hofmann, T

2002-01-01

Very recently, 3-hydroxy-4-[(E)-(2-furyl)methylidene]methyl-3-cyclopentene-1,2-dione (1) has been successfully identified as an intensively coloured Maillard product formed from glucose and L-proline upon thermal food processing. Using a biomimetic synthetic strategy, reference material of compound 1 was prepared and purified, and then used to study its effect on the growth of human tumor cells. Compound 1 was found to potently inhibit the growth of human tumor cells in vitro. Using a reporter gene assay we could show that in growth inhibitory concentrations compound 1 effectively inhibits the phosphorylation of the transcription factor Elk-1. In addition, 1 was found to affect the microtubule skeleton. The human mammary carcinoma cell line MCF-7 exhibits a decrease of the microtubule organisation when treated for 24 h with 1 (> or =20 microM). At concentrations of 30 microM and above a loss of microtubule integrity is observed after 1 h incubation. In vitro studies demonstrated that the polymerisation and, to a minor extent, also the depolymerisation of tubulin, isolated and purified from bovine brain, is inhibited in a dose-dependent manner at concentrations of 30 microM and above. This is the first time that a non-enzymatically formed browning compound of known structure was reported to effectively inhibit tumor cell growth and microtubule assembly.