Sample records for alh3 vliyanie dobavok

  1. Doping of AlH3 with alkali metal hydrides for enhanced decomposition kinetics

    NASA Astrophysics Data System (ADS)

    Sandrock, Gary; Reilly, James

    2005-03-01

    Aluminum hydride, AlH3, has inherently high gravimetric and volumetric properties for onboard vehiclular hydrogen storage (10 wt% H2 and 0.148 kg H2/L). Yet it has been widely neglected because of its kinetic limitations for low-temperature H2 desorption and the thermodynamic difficulties associated with recharging. This paper considers a scenario whereby doped AlH3 is decomposed onboard and recharged offboard. In particular, we show that particle size control and doping with small levels of alkali metal hydrides (e.g., LiH) results in accelerated H2 desorption rates nearly high enough to supply fuel-cell and ICE vehicles. The mechanism of enhanced H2 desorption is associated with the formation of alanate windows (e.g., LiAlH4) between the AlH3 particles and the external gas phase. These alanate windows can be doped with Ti to further enhance transparency, even to the point of accomplishing slow decomposition of AlH3 at room temperature. It is highly likely 2010 gravimetric and volumetric vehicular system targets (6 wt% H2 and 0.045 kg/L) can be met with AlH3. But a new, low-cost method of offboard regeneration of spent Al back to AlH3 is yet needed.

  2. First-principles prediction of low-energy structures for AlH3

    NASA Astrophysics Data System (ADS)

    Sun, Shoutian; Ke, Xuezhi; Chen, Changfeng; Tanaka, Isao

    2009-01-01

    We report density-functional calculations that predict ten different low-energy structures for aluminum hydride AlH3 with space groups Pnma , P6/mmm , I4/mcm , P4/mbm , P4/nmm , Pm3¯m , P21/m , P21/c , Pbcm , and P4/n . Phonon calculations within harmonic approximation reveal unstable modes in the P6/mmm , I4/mcm , P4/mbm , P4/nmm , Pm3¯m , P21/m , and P21/c structures, indicating that they are unstable at low temperatures. The calculations show that the thermodynamic stabilities for AlH3 with space groups Pnma , Pbcm , and P4/n are overall close to the existing α - and γ-AlH3 . From x-ray powder-diffraction patterns, the simulated main-peak positions for AlH3 (P4/n) are in good agreement with experimental δ-AlH3 . A full Rietveld analysis reveals that the fitting space groups R3¯c , Pbcm , and Pnma to the experimental x-ray powder-diffraction pattern of α-AlH3 gives almost the same satisfactory result.

  3. Electron band structure of the high pressure cubic phase of AlH3

    NASA Astrophysics Data System (ADS)

    Shi, Hongliang; Zarifi, Niliffar; Yim, Wai-Leung; Tse, J. S.

    2012-07-01

    The electronic band structure of the cubic Pm3n phase of AlH3 stable above 100 GPa is examined with semi-local, Tran-Blaha modified Becke-Johnson local density approximation (TB-mBJLDA), screened hybrid density functionals and GW methods. The shift of the conduction band to higher energy with increasing pressure is predicted by all methods. However, there are significant differences in detail band structure. In the pressure range from 90 to160 GPa, semi-local, hybrid functional and TB-mBJLDA calculations predicted that AlH3 is a poor metal. In comparison, GW calculations show a gap opening at 160 GPa and AlH3 becomes a small gap semi-conductor. From the trends of the calculated band shifts, it can be concluded that the favourable conditions leading to the nesting of Fermi surfaces predicted by semi-local calculation have disappeared if the exchange term is included. The results highlight the importance of the correction to the exchange energy on the band structure of hydrogen dominant dense metal hydrides at high pressure hydrides and may help to rationalize the absence of superconductivity in AlH3 from experimental measurements.

  4. Chemical Bonding of AlH3 Hydride by Al-L2,3 Electron Energy-Loss Spectra and First-Principles Calculations

    PubMed Central

    Tatsumi, Kazuyoshi; Muto, Shunsuke; Ikeda, Kazutaka; Orimo, Shin-Ichi

    2012-01-01

    In a previous study, we used transmission electron microscopy and electron energy-loss (EEL) spectroscopy to investigate dehydrogenation of AlH3 particles. In the present study, we systematically examine differences in the chemical bonding states of Al-containing compounds (including AlH3) by comparing their Al-L2,3 EEL spectra. The spectral chemical shift and the fine peak structure of the spectra were consistent with the degree of covalent bonding of Al. This finding will be useful for future nanoscale analysis of AlH3 dehydrogenation toward the cell. PMID:28816996

  5. Biogenic Magnetite in Martian Meteorite ALH84001

    NASA Technical Reports Server (NTRS)

    Thomas-Keprta, K. L.; Bazylinski, Dennis; Wentworth, Susan J.; McKay, David S.; Kirschvink, Joseph L.; Clemett, SImon J.; Bell, Mary Sue; Golden, D. C.; Gibson, Everett K., Jr.

    1999-01-01

    Fine-grained magnetite (Fe3O4) in martian meteorite ALH84001, generally less than 200 nm in size, is located primarily in the rims that surround the carbonate globules. There are two populations of ALH84001 magnetites, which are likely formed at low temperature by inorganic and biogenic processes. Nearly 27% of ALH84001 magnetite particles, also called elongated prisms, have characteristics which make them uniquely identifiable as biological precipitates. Additional information is contained in the original extended abstract.

  6. Electrical conductivity of aluminum hydride AlH3 at high pressure and temperature

    NASA Astrophysics Data System (ADS)

    Shakhray, Denis; Molodets, Alexander; Fortov, Vladimir; Khrapak, Aleksei

    2009-06-01

    A study of electrophysical and thermodynamic properties of alane AlH3 under multi shock compression has been carried out. The increase in specific electroconductivity of alane at shock compression up to pressure 100 GPa have been measured. High pressures and temperatures were obtained with explosive device, which accelerates the stainless impactor up to 3 km/sec. The impact shock is split into a shock wave reverberating in alane between two stiff metal anvils. The conductivity of shocked alane increases in the range up to 60-75 GPa and is about 30 1/Ohm*cm. In this region the semiconductor regime is true for shocked alane. The conductivity of alane achieves approximately 500 1/Ohm*cm at 80-90 GPa. In this region conductivity is interpreted in frames of the conception of the ``dielectric catastrophe'', taking into consideration significant difference between electronic states of isolated AlH3 molecule and condensed alane.

  7. Metallization of aluminum hydride AlH3 at high multiple-shock pressures

    NASA Astrophysics Data System (ADS)

    Molodets, A. M.; Shakhray, D. V.; Khrapak, A. G.; Fortov, V. E.

    2009-05-01

    A study of electrophysical and thermodynamic properties of alane AlH3 under multishock compression has been carried out. The increase in specific electroconductivity of alane at shock compression up to pressure 100 GPa has been measured. High pressures and temperatures were obtained with an explosive device, which accelerates the stainless impactor up to 3 km/s. A strong shock wave is generated on impact with a holder containing alane. The impact shock is split into a shock wave reverberating in alane between two stiff metal anvils. This compression loads the alane sample by a multishock manner up to pressure 80-90 GPa, heats alane to the temperature of about 1500-2000 K, and lasts 1μs . The conductivity of shocked alane increases in the range up to 60-75 GPa and is about 30(Ωcm)-1 . In this region the semiconductor regime is true for shocked alane. The conductivity of alane achieves approximately 500(Ωcm)-1 at 80-90 GPa. In this region, conductivity is interpreted in frames of the conception of the “dielectric catastrophe,” taking into consideration significant differences between the electronic states of isolated molecule AlH3 and condensed alane.

  8. Petrologic and oxygen isotopic study of ALH 85085-like chondrites

    NASA Astrophysics Data System (ADS)

    Prinz, M.; Weisberg, M. K.; Clayton, R. N.; Mayeda, T. K.; Ebihara, M.

    1994-07-01

    Four meteorites (PAT 91546, PCA 91328, PCA 91452, PCA 91467) petrologically similar to ALH 85085 chondrite have now been found. Previous studies of ALH 85085 showed it be a new kind of CR-related microchondrule-bearing chondrite, although one called it a sub-chondrite. The purpose of this study is to learn more about ALH 85085-like meteorites and their relationship to CR and CR-related (LEW 85332, Acfer 182, Bencubbin) chondrites. The methods used included petrology, INA bulk chemical analysis (PAT 91546, PCA 91467), and O isotopic analyses of the whole rocks and separated chondrules and dark inclusions (DIs) from PAT 91546. Since microchondrules and fragments are approximately 20 microns it was necessary to analyze composite samples for O; one was of approximately 100 chondrules, and another was of 5 DIs. Petrologically, the four meteorites are similar to ALH 85085, and there is no basis for determining if all of them, or any combinations, are paired. Mineralogically, olivine and pyroxene are highly magnesian FeNi metal generally has 3-10% Ni, and has a positive Ni-Co correlation similar to that in CR and CR-related chondrites. Refractory inclusions are similar in size to the chondrules and have the following assemblages: (1) hibonite-perovskite, (2) melilite-fassaite-forsterite, (3) grossite (Ca-dialuminate)-melilite-perovskite, (4) spinel-melilite, and (5) spinel-pyroxene aggregates. Chemically, INA analyses indicate that PAT 91546 and PCA 91467 are generally similar to ALH 85085. Oxygen isotopic analyses of the four whole-rock compositions fall along the CR mixing line as does ALH 85085; they are also close to LEW 85332, Acfer 182, and Bencubbin. This supports the concept that these are all CR-related chondrites. Even stronger support is found in the compositions of the chondrules and DIs in PAT 91546, which also plot on or near the CR line.

  9. Focused Ion Beam Microscopy of ALH84001 Carbonate Disks

    NASA Technical Reports Server (NTRS)

    Thomas-Keprta, Kathie L.; Clemett, Simon J.; Bazylinski, Dennis A.; Kirschvink, Joseph L.; McKay, David S.; Vali, Hojatollah; Gibson, Everett K., Jr.; Romanek, Christopher S.

    2005-01-01

    Our aim is to understand the mechanism(s) of formation of carbonate assemblages in ALH84001. A prerequisite is that a detailed characterization of the chemical and physical properties of the carbonate be established. We present here analyses by transmission electron microscopy (TEM) of carbonate thin sections produced by both focused ion beam (FIB) sectioning and ultramicrotomy. Our results suggest that the formation of ALH84001 carbonate assemblages were produced by considerably more complex process(es) than simple aqueous precipitation followed by partial thermal decomposition as proposed by other investigators [e.g., 1-3].

  10. Search for Unique Organic Biomarkers in ALH84001

    NASA Technical Reports Server (NTRS)

    Zare, Richard N.

    1999-01-01

    Four goals were outlined for this project. These were: [1] to reproduce the measurement of polycyclic aromatic hydrocarbons (PAHS) in ALH84001 with both a higher spatial resolution and sensitivity than has been previously reported; [2] to extend such measurements to include other members of the Martian SNC (Shergotties, Nahklites, and Chassigny) meteorite clan, in particular the Antarctic Martian meteorite EETA79001; [3] to address issues of potential organic contamination, because at present very little is known about the effect of terrestrial weathering in the Antarctic environment as it pertains to perturbing an indigenous organic distribution within a meteoritic matrix; and [4] to diversify the range of organic compounds studied to include species that can serve as unique biological markers - "molecular fossils" - derived from once living organisms. In order to achieve this, three specific goals were outlined for the funding period 06/01/97 to 02/28/98. They were: [1] to investigate the effects of terrestrial weathering and organic contamination of meteoritic samples collected from Antarctica; [2] to reproduce and extend upon the measurements of PAHs in ALH84001 with the aim of establishing or refuting the indigeneity of these species; and [3] to extend the analysis of organic compounds in ALH84001 and EETA79001 to address compounds that are considered to be more biologically relevant than PAHS. All three were successfully accomplished, as detailed in the previous performance report. In brief, however, the results achieved were to establish that the PAHs found in ALH84001 were indigenous and not due to contamination, and to determine that a novel and sensitive technique in meteoritic work, capillary zone electrophoresis (CE), could indeed detect amino acids, a potential class of biomarker.

  11. ALH84001: The Key to Unlocking Secrets About Mars-15 Years and Counting

    NASA Technical Reports Server (NTRS)

    Gibson, Everett K.; McKay, D. S.; Thomas-Keprta, K. L.; Clemett, S. J.

    2011-01-01

    From the December 27, 1984 discovery of ALH84001, and its subsequent identification as a sample of Mars in 1993, mystery and debate has surrounded the meteorite [1]. With the realization that the ALH84001 sample was a orthopyroxenite and one of the oldest SNC meteorites (approx.4.09 Ga) [2] available to study, important and critical information about the Martian hydrosphere and atmosphere along with the early history and evolution of the planet could be obtained by studying the unique carbonate globules (approx.3.9 Ga) in the sample [3]. The initial work showed the carbonate globules were deposited within fractures and cracks in the host-orthopyroxene by low-temperature aqueous fluids [4]. Ideas that the carbonates were formed at temperatures [5] approaching 800 C were ruled out by later experiments [6]. The 1996 announcement by McKay et al. [7] that ALH84001 contained features which could be interpreted as having a biogenic origin generated considerable excitement and criticism. The NASA Administrator Dan Golden said the 1996 ALH84001 announcement saved NASAs Mars planetary exploration program and injected $6 billion dollars over five years into the scientific research and analysis efforts [8]. All of the original four lines of evidence for possible biogenic features within ALH84001 offered by McKay et al. have withstood the test of time. Criticism has been directed at the interpretation of the 1996 analytical data. Research has expanded to other SNC meteorites. Despite the numerous attacks on the ideas, the debate continues after 15 years. The 2009 paper by Thomas-Keprta et al. [9] on the origins of a suite of magnetites within the ALH84001 has offered strong arguments that some of the magnetites can only be formed by biogenic processes and not from thermal decomposition or shock events which happened to the meteorite. NASA s Astrobiology Institute was formed from the foundation laid by the ALH84001 hypothesis of finding life beyond the Earth. The strong

  12. SXRF determination of trace elements in chondrule rims in the unequilibrated CO3 chondrite, ALH A77307

    NASA Technical Reports Server (NTRS)

    Brearley, Adrian J.; Bajt, Sasa; Sutton, Steve R.; Papike, J. J.

    1993-01-01

    The concentrations of Ni, Cu, Zn, Ga, Ge, and Se in five chondrule rims in the CO3 chondrite ALH A77307 (3.0) using the synchrotron x-ray fluorescence (SXRF) microprobe at Brookhaven National Laboratory were determined. The data show that the trace element chemistry of rims on different chondrules is remarkably similar, consistent with data obtained for the major elements by electron microprobe. These results support the idea that rims are not genetically related to individual chondrules, but all sampled the same reservoir of homogeneously mixed dust. Of the trace elements analyzed Zn and Ga show depletions relative to CI chondrite values, but in comparison with bulk CO chondrites all the elements are enriched by approximately 1.5 to 3.5 x CO. The high concentrations of the highly volatile elements Se and Ga and moderately volatile Zn (1.5 to 2 x CO) in rims show that matrix is the major reservoir of volatile elements in ALH A77307.

  13. Terahertz Spectroscopy of CrH (X 6Σ+) and AlH (X 1Σ+)

    NASA Astrophysics Data System (ADS)

    Halfen, D. T.; Ziurys, L. M.

    2016-12-01

    New laboratory measurements of hydrides have been carried out using terahertz direct absorption spectroscopy. Spin components of the N=2≤ftarrow 1 transition of the free radical CrH (X 6Σ+) have been recorded in the range 730-734 GHz, as well as a new measurement of the J=2≤ftarrow 1 line of AlH (X 1Σ+) near 755 GHz. Both species were created in an AC discharge of H2, argon, and metal vapor. For CrH, the chromium source was Cr(CO)6, while AlH was produced from Al(CH3)3. The J=4.5≤ftarrow 3.5 and 3.5≤ftarrow 2.5 fine-structure components were recorded for CrH, each which consists of resolved proton hyperfine doublets. For AlH, the two main quadrupole components, F=4.5≤ftarrow 3.5 and 3.5≤ftarrow 2.5, of the J=2≤ftarrow 1 transition were observed as blended features. These data were analyzed with previous 1≤ftarrow 0 millimeter/submillimeter measurements with 6Σ and 1Σ Hamiltonians for chromium and aluminum hydrides, respectively, and rotational, fine-structure (CrH only), and hyperfine constants were derived. The new measurements have resulted in refined spectroscopic parameters for both species, as well as direct measurement of the respective 2≤ftarrow 1 rotational transitions. This work also resolves a 10 MHz discrepancy in the frequency of the AlH line. CrH and AlH have already been observed in the photospheres of stars via their electronic transitions. These data will facilitate their discovery at submillimeter/terahertz wavelengths in circumstellar envelopes and perhaps in diffuse clouds.

  14. Modern terrestrial analogues for the carbonate globules in Martian meteorite ALH84001.

    PubMed

    Kazmierczak, Józef; Kempe, Stephan

    2003-04-01

    Modern carbonate globules, located in cracks of submerged volcanic rocks and in calcareous pinnacles in alkaline (sodic) Lake Van, Turkey, appear to be analogues for the approximately 3.9 billion-year-old carbonate globules in Martian meteorite ALH84001. These terrestrial globules have similar diameters and are chemically and mineralogically zoned. Furthermore, they display surface and etching structures similar to those described from ALH84001, which were interpreted as fossilized microbial forms. These terrestrial carbonates formed at low temperatures where Ca-rich groundwaters enter the lake. Chemical, mineralogical, microbiological, and biomolecular methods were used in an attempt to decipher the process responsible for the genesis of these structures. Although the exact mode of formation of Lake Van carbonates remains an enigma, their similarity to the Martian globules indicates that the ALH84001 carbonates may have formed in similar setting on ancient Mars.

  15. ALH84001: The Key to Unlocking Secrets About Mars-15 Years and Counting

    NASA Technical Reports Server (NTRS)

    Gibson, Everett K.

    2011-01-01

    From the December 27, 1984 discovery of ALH84001, and its subsequent identification as a sample of Mars in 1993, mystery and debate has surrounded the meteorite. With the realization that the ALH84001 sample was a orthopyroxenite and one of the oldest SNC meteorites (4.09 Ga) available to study, important and critical information about the Martian hydrosphere and atmosphere along with the early history and evolution of the planet could be obtained by studying the unique carbonate globules (3.9 Ga) in the sample. The initial work showed the carbonate globules were deposited within fractures and cracks in the host-orthopyroxene by low-temperature aqueous fluids. Ideas that the carbonates were formed at temperatures approaching 800oC were ruled out by later experiments. The 1996 announcement by McKay et al. that ALH84001 contained features which could be interpreted as having a biogenic origin generated considerable excitement and criticism. The NASA Administrator Dan Golden said the 1996 ALH84001 announcement saved NASA s Mars planetary exploration program and injected $6 billion dollars over five years into the scientific research and analysis efforts. All of the original four lines of evidence for possible biogenic features within ALH84001 offered by McKay et al. have withstood the test of time. Criticism has been directed at the interpretation of the 1996 analytical data. Research has expanded to other SNC meteorites. Despite the numerous attacks on the ideas, the debate continues after 15 years. The 2009 paper by Thomas-Keprta et al. on the origins of a suite of magnetites within the ALH84001 has offered strong arguments that some of the magnetites can only be formed by biogenic processes and not from thermal decomposition or shock events which happened to the meteorite. NASA s Astrobiology Institute was formed from the foundation laid by the ALH84001 hypothesis of finding life beyond the Earth. The strong astrobiology outreach programs have expanded because of

  16. Truncated Hexa-Octahedral Magnetite Crystals in Martian Meteorite ALH84001: Evidence of Biogenic Activity on Early Mars

    NASA Technical Reports Server (NTRS)

    Thomas-Keprta, K.; Clemett, S. J.; Schwartz, C.; McIntosh, J. R.; Bazylinski, D. A.; Kirschvink, J.; McKay, D. S.; Gibson, E. K.; Vali, H.; Romanek, C. S.

    2004-01-01

    The landmark paper by McKay et al. [1] cited four lines of evidence associated with the Martian meteorite ALH84001 to support the hypothesis that life existed on Mars approximately 4 Ga ago. Now, more than five years later, attention has focused on the ALH84001 magnetite grains embedded within carbonate globules in the ALH84001 meteorite. We have suggested that up to approx.25% of the ALH84001 magnetite crystals are products of biological activity [e.g., 2]. The remaining magnetites lack sufficient characteristics to constrain their origin. The papers of Thomas Keprta et al. were criticized arguing that the three dimensional structure of ALH84001 magnetite crystals can only be unambiguously determined using electron tomographic techniques. Clemett et al. [3] confirmed that magnetites produced by magnetotactic bacteria strain MV-I display a truncated hexa-octahedral geometry using electron tomography and validated the use of the multi-tilt classical transmission microscopy technique used by [2]. Recently the geometry of the purported martian biogenic magnetites was shown be identical to that for MV-1 magnetites using electron tomography [6].

  17. Geochemical evidence for mixing of three components in martian orthopyroxenite ALH 84001. [Abstract only

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, D. W.; Lindstrom, M. M.

    1994-01-01

    ALH 84001, a ferroan martian orthopyroxenite, originally consisted of three petrographically defined components: a cumulus assemblage of orthopyroxene + chromite, a trapped melt assemblage of orthopyroxene(?) + chromite + maskelynite + apatite + augite +/- pyrite, and a metasomatic assemblage of carbonate +/- pyrite. We present the results of Instrumental Neutron Activation Analysis (INAA) study of five bulk samples of ALH 84001, combined with Scanning Ion Mass Spectrometer (SIMS) data on the orthopyroxene, in order to attempt to set limits on the geochemical characteristics of the latter two components, and therefore on the petrogenesis of ALH 84001. The INAA data support the petrographic observations, suggesting that there are at least three components in ALH 84001. We will assume that each of the three geochemically required components can be equated with one of the petrographically observed components. Both trapped melt and metasomatic components in ALH 84001 have higher Na than orthopyroxene based on compositions of maskelynite, apatite, and carbonate. For the metasomatic component, we will assume its Na content is that of carbonate, while for a trapped melt component, we will use a typical Na content inferred for martian meteorite parent melts, approximately 1 wt% Na2O. Under these assumptions, we can set limits on the Light Rare Earth Elements/Heavy Rare Earth Elements (LREE/HREE) ratios of the components, and use this information to compare the petrogenesis of ALH 84001 with other martian meteorites. The above calculations assume that the bulk samples are representative of different portions of ALH 84001. We will also evaluate the possible heterogeneous distribution of mineral phases in the bulk samples as the cause of compositional heterogeneity in our samples.

  18. The Origin of Magnetite Crystals in ALH84001 Carbonate Disks

    NASA Technical Reports Server (NTRS)

    Thomas-Keprta, K. L.; Clemett, S. J.; Wentworth, S. J.; McKay, D. S.; Gibson, E. K., Jr.

    2012-01-01

    Martian meteorite ALH84001 preserves evidence of interaction with aqueous fluids while on Mars in the form of microscopic carbonate disks believed to have formed approx 3.9 Ga ago at beginning of the Noachian epoch. Intimately associated within and throughout these carbonate disks are nanocrystal magnetites (Fe3O4) with unusual chemical and physical properties, whose origins have become the source of considerable debate. One group of hypotheses argues that these magnetites are the product of partial thermal decomposition of the host carbonate. Alternatively, the origins of magnetite and carbonate may be unrelated; that is, from the perspective of the carbonate the magnetite is allochthonous. We have sought to resolve between these hypotheses through the detailed characterized of the compositional and structural relationships between the carbonate disks, their associated magnetites and the orthopyroxene matrix in which they are embedded. Comparison of these results with experimental thermal decomposition studies of sideritic carbonates conducted under a range of heating scenarios suggests that the magnetite nanocrystals in the ALH84001 carbonate disks are not the products of thermal decomposition.

  19. ExoMol line lists XXVIII: The rovibronic spectrum of AlH

    NASA Astrophysics Data System (ADS)

    Yurchenko, Sergei N.; Williams, Henry; Leyland, Paul C.; Lodi, Lorenzo; Tennyson, Jonathan

    2018-06-01

    A new line list for AlH is produced. The WYLLoT line list spans two electronic states X 1Σ+ and A 1Π. A diabatic model is used to model the shallow potential energy curve of the A 1Π state, which has a strong pre-dissociative character with only two bound vibrational states. Both potential energy curves are empirical and were obtained by fitting to experimentally derived energies of the X 1Σ+ and A 1Π electronic states using the diatomic nuclear motion codes DPOTFIT and DUO. High temperature line lists plus partition functions and lifetimes for three isotopologues 27AlH, 27AlD and 26AlH were generated using ab initio dipole moments. The line lists cover both the X-X and A-X systems and are made available in electronic form at the CDS and ExoMol databases.

  20. Origin of Magnetite Crystals in Martian Meteorite ALH84001 Carbonate Disks

    NASA Technical Reports Server (NTRS)

    Thomas-Keprta, K.L.; Clemett, S.J.; McKay, D.S.; Gibson, E. K.; Wentworth, S. J.

    2010-01-01

    Martian meteorite ALH84001 preserves evidence of interaction with aqueous fluids while on Mars in the form of microscopic carbonate disks which are believed to have precipitated approx.3.9 Ga ago at beginning of the Noachian epoch. Intimately associated within and throughout these carbonate disks are nanocrystal magnetites (Fe3O4) with unusual chemical and physical properties, whose origins have become the source of considerable debate. One group of hypotheses argues that these Fe3O4 are the product of partial thermal decomposition of the host carbonate. Alternatively, the origins of Fe3O4 and carbonate may be unrelated; that is, from the perspective of the carbonate the magnetite is allochthonous. We have sought to resolve between these hypotheses through the detailed characterized of the compositional and structural relationships of the carbonate disks and associated magnetites with the orthopyroxene matrix in which they are embedded [1]. We focus this discussion on the composition of ALH84001 magnetites and then compare these observations with those from our thermal decomposition studies of sideritic carbonates under a range of plausible geological heating scenarios.

  1. A Petrographic History of Martian Meteorite ALH84001: Two Shocks and an Ancient Age

    NASA Technical Reports Server (NTRS)

    Treiman, Allan H.

    1995-01-01

    ALH84001 is an igneous meteorite, an orthopyroxenite of martian origin. It contains petrographic evidence of two shock metamorphic events, separated by thermal and chemical events. The evidence for two shock events suggests that ALH84001 is ancient and perhaps a sample of the martian highlands. From petrography and mineral chemistry, the history of ALH84001 must include: crystallization from magma, a first shock (impact) metamorphism, thermal metamorphism, low-temperature chemical alteration, and a second shock (impact) metamorphism. Originally, ALH84001 was igneous, an orthopyroxene-chromite cumulate. In the first shock event, the igneous rock was cut by melt-breccia or cataclastic veinlets, now bands of equigranular fine-grained pyroxene and other minerals (crush zones). Intact fragments of the cumulate were fractured and strained (now converted to polygonized zones). The subsequent thermal metamorphism (possibly related to the first shock) annealed the melt-breccia or cataclastic veinlets to their present granoblastic texture and permitted chemical homogenization of all mineral species present. The temperature of metamorphism was at least 875 C, based on mineral thermometers. Next, Mg-Fe-Ca carbonates and pyrite replaced plagioclase in both clasts and granular bands, producing ellipsoidal carbonate globules with sub-micron scale compositional stratigraphy, repeated identically in all globules, The second shock event produced microfault offsets of carbonate stratigraphy and other mineral contacts, radial fractures around chromite and maskelynite, and strain birefringence in pyroxene. Maskelynite could not have been preserved from the first shock event, because it would have crystallized back to plagioclase. The martian source area for ALH84001 must permit this complex, multiple impact history. Very few craters on young igneous surfaces are on or near earlier impact features. It is more likely that ALH84001 was ejected from an old igneous unit (Hesperian or

  2. Determination of the Three-Dimensional Morphology of ALH84001 and Biogenic MV-1 Magnetite: Comparison of Results from Electron Tomography and Classical Transmission Electron Microscopy

    NASA Technical Reports Server (NTRS)

    Thomas-Keprta, Kathie L.; Clemett, Simon J.; Schwartz, Cindy; Morphew, Mary; McIntosh, J. Richard; Bazylinski, Dennis A.; Kirschvink, Joseph L.; Wentworth, Susan J.; McKay, David S.; Vali, Hojatollah

    2004-01-01

    Dated at approximately 3.9 billion years of age, carbonate disks, found within fractures of the host rock of Martian meteorite ALH84001, have been interpreted as secondary minerals that formed at low temperature in an aqueous medium. Heterogeneously distributed within these disks are magnetite nanocrystals that are of Martian origin. Approximately one quarter of these magnetites have morphological and chemical similarities to magnetite particles produced by magnetotactic bacteria strain MV-1, which are ubiquitous in aquatic habitats on Earth. Moreover, these types of magnetite particles are not known or expected to be produced by abiotic means either through geological processes or synthetically in the laboratory. The remaining three quarters of the ALH84001 magnetites are likely products of multiple processes including, but not limited to, precipitation from a hydrothermal fluid, thermal decomposition of the carbonate matrix in which they are embedded, and extracellular formation by dissimilatory Fe-reducing bacteria. We have proposed that the origins of magnetites in ALH84001 can be best explained as the products of multiple processes, one of which is biological. Recently the three-dimensional (3-D) external morphology of the purported biogenic fraction of the ALH84001 magnetites has been the subject of considerable debate. We report here the 3-D geometry of biogenic magnetite crystals extracted from MV-1 and of those extracted from ALH84001 carbonate disks using a combination of high resolution classical and tomographic transmission electron microscopy (TEM). We focus on answering the following questions: (1) which technique provides adequate information to deduce the 3-D external crystal morphology?; and, (2) what is the precise 3-D geometry of the ALH84001 and MV-1 magnetites?

  3. Microstructures of Hibonite From an ALH A77307 (CO3.0) CAI: Evidence for Evaporative Loss of Calcium

    NASA Technical Reports Server (NTRS)

    Han, Jangmi; Brearley, Adrian J.; Keller, Lindsay P.

    2014-01-01

    Hibonite is a comparatively rare, primary phase found in some CAIs from different chondrite groups and is also common in Wark-Lovering rims [1]. Hibonite is predicted to be one of the earliest refractory phases to form by equilibrium condensation from a cooling gas of solar composition [2] and, therefore, can be a potential recorder of very early solar system processes. In this study, we describe the microstructures of hibonite from one CAI in ALH A77307 (CO3.0) using FIB/TEM techniques in order to reconstruct its formational history.

  4. Truncated hexa-octahedral magnetite crystals in ALH84001: Presumptive biosignatures

    PubMed Central

    Thomas-Keprta, Kathie L.; Clemett, Simon J.; Bazylinski, Dennis A.; Kirschvink, Joseph L.; McKay, David S.; Wentworth, Susan J.; Vali, Hojatollah; Gibson, Everett K.; McKay, Mary Fae; Romanek, Christopher S.

    2001-01-01

    McKay et al. [(1996) Science 273, 924–930] suggested that carbonate globules in the meteorite ALH84001 contained the fossil remains of Martian microbes. We have characterized a subpopulation of magnetite (Fe3O4) crystals present in abundance within the Fe-rich rims of these carbonate globules. We find these Martian magnetites to be both chemically and physically identical to terrestrial, biogenically precipitated, intracellular magnetites produced by magnetotactic bacteria strain MV-1. Specifically, both magnetite populations are single-domain and chemically pure, and exhibit a unique crystal habit we describe as truncated hexa-octahedral. There are no known reports of inorganic processes to explain the observation of truncated hexa-octahedral magnetites in a terrestrial sample. In bacteria strain MV-1 their presence is therefore likely a product of Natural Selection. Unless there is an unknown and unexplained inorganic process on Mars that is conspicuously absent on the Earth and forms truncated hexa-octahedral magnetites, we suggest that these magnetite crystals in the Martian meteorite ALH84001 were likely produced by a biogenic process. As such, these crystals are interpreted as Martian magnetofossils and constitute evidence of the oldest life yet found. PMID:11226210

  5. Truncated hexa-octahedral magnetite crystals in ALH84001: presumptive biosignatures

    NASA Technical Reports Server (NTRS)

    Thomas-Keprta, K. L.; Clemett, S. J.; Bazylinski, D. A.; Kirschvink, J. L.; McKay, D. S.; Wentworth, S. J.; Vali, H.; Gibson, E. K. Jr; McKay, M. F.; Romanek, C. S.

    2001-01-01

    McKay et al. [(1996) Science 273, 924-930] suggested that carbonate globules in the meteorite ALH84001 contained the fossil remains of Martian microbes. We have characterized a subpopulation of magnetite (Fe(3)O(4)) crystals present in abundance within the Fe-rich rims of these carbonate globules. We find these Martian magnetites to be both chemically and physically identical to terrestrial, biogenically precipitated, intracellular magnetites produced by magnetotactic bacteria strain MV-1. Specifically, both magnetite populations are single-domain and chemically pure, and exhibit a unique crystal habit we describe as truncated hexa-octahedral. There are no known reports of inorganic processes to explain the observation of truncated hexa-octahedral magnetites in a terrestrial sample. In bacteria strain MV-1 their presence is therefore likely a product of Natural Selection. Unless there is an unknown and unexplained inorganic process on Mars that is conspicuously absent on the Earth and forms truncated hexa-octahedral magnetites, we suggest that these magnetite crystals in the Martian meteorite ALH84001 were likely produced by a biogenic process. As such, these crystals are interpreted as Martian magnetofossils and constitute evidence of the oldest life yet found.

  6. Carbon Compounds from Mars Found Inside Meteorite ALH84001

    NASA Image and Video Library

    1996-08-08

    This 4.5 billion-year-old rock, labeled meteorite ALH84001, is one of 10 rocks from Mars in which researchers have found organic carbon compounds that originated on Mars without involvement of life. http://photojournal.jpl.nasa.gov/catalog/PIA00289

  7. New Insights into the Origin of Magnetite Crystals in ALH84001 Carbonate Disks

    NASA Technical Reports Server (NTRS)

    Thomas-Keptra, Katie L.; Clemett, S. J.; Wentworth S. J.; Mckay, D. S.; Gibson, E. K., Jr.

    2010-01-01

    Martian meteorite ALH84001 preserves evidence of interaction with aqueous fluids while on Mars in the form of microscopic carbonate disks believed to have formed approx.3.9 Ga ago at beginning of the Noachian epoch. Intimately associated within and throughout these carbonate disks are nanocrystal magnetites (Fe3O4) with unusual chemical and physical properties, whose ori gins have become the source of considerable debate. One group of hypotheses argues that these magnetites are the product of partial thermal decomposition of the host carbonate. Alternatively, the origins of magnetite and carbonate may be unrelated: that is, from the perspective of the carbonate the magnetite is allochthonous. We have sought to resolve between these hypotheses through the detailed characterized of the compositional and structural relationships between the carbonate disks, their associated magnetites and the orthopyroxene matrix in which they are embedded [1]. Comparison of these results with experimental thermal decomposition studies of sideritic carbonates conducted under a range of heating scenarios suggests that the magnetite nanocrystals in the ALH84001 carbonate disks are not the products of thermal decomposition.

  8. LEW 88180, LEW 87119, and ALH 85119: New EH6, EL7, and EL4 Enstatite Chondrites

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Benoit, P. H.; Sears, D. W. G.

    1993-07-01

    The EH and EL chondrites formed in a uniquely reducing environment, containing low-Fe pyroxene, abundant metal, and a number of unusual sulphides and other minerals [1]. An important aspect of their history is that while the EL chondrites consist predominantly of metamorphosed meteorites, the EH consist primarily of little-metamorphosed meteorites (e.g., [2]), and yet EL chondrites have lower equilibrium temperatures than EH chondrite [3,4]. To help understand this observation and its implication for the history of the classes, we have been searching for new enstatite chondrites, looking especially for meteorites of previously unknown chemical-petrologic class. Using our normal INAA methods [5] and sample splits of 100-200 mg, the bulk composition of nine Antarctic enstatite chondrites and one fall were determined. The data were used to assign the meteorites to chemical classes, the Ni/Ir vs. Al/V plot (Fig. 1) being especially useful since it uses the refractory element difference between EH and EL chondrites and is insensitive to metal-silicate heterogeneity. The well-analyzed Qingzhen was included to check our method. ALH84170, ALH84206, and EET87746, which Mason described as E3, E4, and E4 were all found to be EH chondrites [6]. Our data for the three paired EL3 chondrites were discussed earlier (MAC88136, 88180, and 88184) [7,8]. LEW88180, LEW87119, and ALH85119, which Mason described as type E6, E6, and E4 respectively [6], are EH, EL, and EL; thus LEW88180 and ALH85119 appear to be the first EH6 and EL4 chondrites. The compositions of kamacite, phosphide, and niningerite-alabandite (Fig. 2) for ALH84170, ALH84206, EET87746, LEW88180, and ALH85119 are consistent with Mason's petrologic type assignments [6]. The mineral composition of LEW88180 (2.7% Si and 9.4% Ni in the kamacite, 7.8% Ni in the phosphide, and 60% FeS in the niningerite) confirms our classification of this meteorite as EH6. ALH85119 contains kamacite with 0.5% Si and 7% Ni, phosphide with 46

  9. Early evolution of Martian volatiles: Nitrogen and noble gas components in ALH84001 and Chassigny

    NASA Astrophysics Data System (ADS)

    Mathew, K. J.; Marti, K.

    2001-01-01

    Studies on SNC meteorites have permitted the characterization of modern Martian atmospheric components as well as indigenous Martian nitrogen and solar-type xenon. New isotopic and elemental abundances of noble gases and nitrogen in ALH84001 and Chassigny provide important constraints on the early evolution of the planet. A primitive solar Xe component (Chass-S) and an evolved Xe component (Chass-E), augmented with fission Xe are identified in Chassigny. Both components represent interior reservoirs of Mars and are characterized by low 129Xe/132Xe (<1.07) and by distinct elemental ratios 36Ar/132Xe<5 and >130, respectively. Light nitrogen (δ15N=-30‰) is associated with the Chass-S component and is enriched in melt inclusions in olivine. An ancient (presumably incorporated ~4 Gyr ago) evolved Martian atmospheric component is identified in ALH84001 and has the following signatures: 129Xe/132Xe=2.16, 36Ar/38Ar>=5.0, 36Ar/132Xe=~50, 84Kr/132Xe=~6, and δ15N=7‰. The trapped Xe component in ALH84001 is not isotopically fractionated. We observe major shifts in nitrogen signatures due to cosmogenic N component in both Chassigny and ALH84001. A heavy nitrogen component of comparable magnitude (δ15N>150‰) has previously been interpreted as (heavy) Martian atmospheric N. In situ produced fission Xe components, due to 244Pu in ALH84001 and due to 238U in Chassigny, are identified. The ALH84001 data strongly constrain exchanges of Martian atmospheric and interior reservoirs. Mars retained abundant fission Xe components, and this may account for the low observed fission Xe component in the modern Martian atmosphere. Chronometric information regarding the evolution of the early Martian atmosphere can be secured from the relative abundances of radiogenic and fission Xe, as ~80% of the Martian 129Xer is observed in the atmospheric 129Xe/132Xe ratio ~ 4 Gyr ago.

  10. Did an Impact Make the Mysterious Microscopic Magnetite Crystals in ALH 84001?

    NASA Astrophysics Data System (ADS)

    Taylor, G. J.

    2007-10-01

    Fervent debate swirls around microscopic crystals of magnetite (Fe3O4) in Martian meteorite ALH 84001. Some investigators suggest that the crystals are evidence of past life on Mars, citing magnetite crystals of similar chemical compositions and sizes made by magnetotactic bacteria on Earth. Others cite assorted experiments and observations to argue that the important little crystals formed entirely by non-biological processes, hence say nothing about life on Mars. One of those processes is the decomposition of iron carbonate (the mineral siderite), which occurs in ALH 84001. Researchers argue that heating this mineral causes it to decompose into magnetite and CO2 gas. Experiments showing this were done by heating siderite and observing that it decomposed and formed magnetite, but nobody had shock-heated siderite to see if magnetite crystals formed. (Shock is a rapid, strong rise and fall in pressure. It happens under many circumstances, including meteorite impacts.) The lack of shock experiments has been solved by Mary Sue Bell (University of Houston and Jacobs Engineering). She experimentally shocked samples of siderite at the Experimental Impact Laboratory at the Johnson Space Center. She shows that magnetite crystals of the right size and composition formed when samples were shocked to 49 GPa (about 500,000 times the pressure at the Earth's surface). This is more evidence for a non-biological origin for the magnetite crystals in ALH 84001 and is consistent with what we know about the impact history of the rock. There seems to be growing evidence against a biological origin, but don't expect these results to completely settle the debate!

  11. Coordinated In Situ Nanosims Analyses of H-C-O Isotopes in ALH 84001 Carbonates

    NASA Technical Reports Server (NTRS)

    Usui, T.; Alexander, C. M. O'D.; Wang, J.; Simon, J. I.; Jones, J. H.

    2016-01-01

    The surface geology and geomorphology of Mars indicate that it was once warm enough to maintain a large body of liquid water on its surface, though such a warm environment might have been transient. This study reports the hydrogen, carbon, and oxygen isotope compositions of the ancient atmosphere/hydrosphere of Mars based on in situ ion microprobe analyses of approximately 4 Ga-old carbonates in Allan Hills (ALH) 84001. The ALH 84001 carbonates are the most promising targets because they are thought to have formed from fluid that was closely associated with the Noachian atmosphere. While there are a number of carbon and oxygen isotope studies of the ALH 84001 carbonates, in situ hydrogen isotope analyses of these carbonates are limited and were reported more than a decade ago. Well-documented coordinated in situ analyses of carbon, oxygen and hydrogen isotopes provide an internally consistent dataset that can be used to constrain the nature of the Noachian atmosphere/hydrosphere and may eventually shed light on the hypothesis of ancient watery Mars.

  12. A first principles calculation and statistical mechanics modeling of defects in Al-H system

    NASA Astrophysics Data System (ADS)

    Ji, Min; Wang, Cai-Zhuang; Ho, Kai-Ming

    2007-03-01

    The behavior of defects and hydrogen in Al was investigated by first principles calculations and statistical mechanics modeling. The formation energy of different defects in Al+H system such as Al vacancy, H in institution and multiple H in Al vacancy were calculated by first principles method. Defect concentration in thermodynamical equilibrium was studied by total free energy calculation including configuration entropy and defect-defect interaction from low concentration limit to hydride limit. In our grand canonical ensemble model, hydrogen chemical potential under different environment plays an important role in determing the defect concentration and properties in Al-H system.

  13. Atomic force microscopy imaging of fragments from the Martian meteorite ALH84001

    NASA Technical Reports Server (NTRS)

    Steele, A.; Goddard, D.; Beech, I. B.; Tapper, R. C.; Stapleton, D.; Smith, J. R.

    1998-01-01

    A combination of scanning electron microscopy (SEM) and environmental scanning electron microscopy (ESEM) techniques, as well as atomic force microscopy (AFM) methods has been used to study fragments of the Martian meteorite ALH84001. Images of the same areas on the meteorite were obtained prior to and following gold/palladium coating by mapping the surface of the fragment using ESEM coupled with energy-dispersive X-ray analysis. Viewing of the fragments demonstrated the presence of structures, previously described as nanofossils by McKay et al. (Search for past life on Mars--possible relic biogenic activity in martian meteorite ALH84001. Science, 1996, pp. 924-930) of NASA who used SEM imaging of gold-coated meteorite samples. Careful imaging of the fragments revealed that the observed structures were not an artefact introduced by the coating procedure.

  14. A mild, near-surface aqueous environment on Noachian Mars preserved in ALH84001

    NASA Astrophysics Data System (ADS)

    Halevy, I.; Fischer, W. W.; Eiler, J. M.

    2011-12-01

    Despite widespread evidence for liquid water at the surface of Mars during parts of the Noachian epoch, the temperature of early aqueous environments has been impossible to establish, raising questions of whether Mars' surface was ever warmer than today. This has hindered insight into aqueous alteration processes, which, on the basis of orbital spectroscopy, appear to have been prevalent on Noachian Mars. It is important to understand such processes, as they link the observed secondary mineral assemblages to interactions between primary igneous silicates and the surface environment (atmosphere-hydrosphere). We have addressed this problem by determining the precipitation temperatures of secondary carbonate minerals preserved in the oldest known sample of Mars' crust-the meteorite Allan Hills 84001 (ALH84001). Using carbonate 'clumped' isotope thermometry we have found that the carbonates in ALH84001, which are 3.9-4.0 billion years old, formed at a temperature of ~18±4°C. With temperature known, we used the carbon and oxygen isotopic composition of the carbonates, as constrained by both our measurements and previous acid digestion and ion microprobe studies, to develop a model for their formation process and environment. The observed isotopic variation is best explained by carbonate precipitation out of a gradually evaporating, shallow subsurface aqueous solution (e.g. a regolith aquifer) at near-constant temperatures. Furthermore, on the basis of the isotopic composition of the earliest precipitated carbonates in ALH84001, the volatiles from which they formed (H2O and CO2) came not from depth, but from the early Martian surface. The occurrence of carbonates in other SNC meteorites and as a minor component of Martian dust implies that environments analogous to the one we studied may have been important in generating some of the observed secondary mineral assemblages by interaction between Mars' igneous crust and its atmosphere-hydrosphere.

  15. Rock Magnetic and Ferromagnetic Resonance Tests of Biogenic Magnetite in ALH84001

    NASA Technical Reports Server (NTRS)

    Kirschvink, J. L.; Kim, S.; Weiss, B. P.; Shannon, D. M.; Kobayashi, A. K.

    2002-01-01

    Three separate rock magnetic and ferromagnetic resonance tests support the hypothesis that between 25 and 50% of the fine-grained magnetite in the Martian meteorite ALH84001 was formed via biological processes. Additional information is contained in the original extended abstract.

  16. LU-HF Age and Isotope Systematics of ALH84001

    NASA Technical Reports Server (NTRS)

    Righter, M.; Lapen, T. J.; Brandon, A. D.; Beard, B. L.; Shafer, J. T.; Peslier, A. H.

    2009-01-01

    Allan Hills (ALH) 84001 is an orthopyroxenite that is unique among the Martian meteorites in having the oldest inferred crystallization age (approx..4.5 to 4.0 Gyr) [e.g., 1-6 and references therein 7]. Its ancient origin makes this stone a critical constraint on early history of Mars, in particular the evolution of different planetary crust and mantle reservoirs. However, because there is significant variability in reported crystallization ages, determination of initial isotope compositions is imprecise making assessment of planetary reservoirs difficult. Here we report a new Lu-Hf mineral isochron age, initial Hf-176/Hf-177 isotope composition, and inferred Martian mantle source compositions for ALH84001 that place constraints on longlived source reservoirs for the enriched shergottite suite of Martian meteorites including Shergotty, Zagami, NWA4468, NWA856, RBT04262, LAR06319, and Los Angeles. Sm-Nd isotope analyses are under way for the same mineral aliquots analyzed for Lu-Hf. The Lu-Hf system was utilized because Lu and Hf are both lithophile and refractory and are not easily redistributed during short-lived thermal pulses associated with shock metamorphism. Moreover, chromite has relatively modest Hf concentrations with very low Lu/Hf ratios [9] yielding tight constraints on initial Hf-176/Hf-177 isotope compositions

  17. Efficacy of horse chestnut leaf extract ALH-L1005 as a matrix metalloproteinase inhibitor in ligature-induced periodontitis in canine model

    PubMed Central

    Kim, Se Eun; Kim, Tae Hyun; Park, Shin Ae; Kim, Won Tae; Park, Young Woo; Ahn, Jae Sang; Jeong, Manbok; Kim, Min-Young

    2017-01-01

    Matrix metalloproteinases (MMPs) are the main proteinases associated with periodontal tissue destruction and remodeling. Therefore, inhibition of host-derived MMPs has a key role in the prevention and reduction of periodontitis progression. Horse chestnut (Aesculus hippocastanum L.) extracts have been used as treatments for inflammatory disease, traditionally. This study assessed the clinical effect as a MMP inhibitor of horse chestnut leaf extract ALH-L1005 on periodontitis. ALH-L1005 was obtained from horse chestnut leaf and its MMP inhibitory activities estimated. Periodontitis was induced in beagles assigned to 4 groups and medicated for 6 weeks: low dose test (LT; ALH-L1005, 100 mg/kg/day), high dose test (HT; ALH-L1005, 200 mg/kg/day), positive control (PC; doxycycline, 10 mg/kg/day), or negative control (NC; placebo). Before and after administration, clinical indices of the teeth and MMP quantity in gingival tissues using zymography were measured. Clinical conditions of the LT, HT, and PC groups were significantly improved after 6 weeks. In zymographic evaluations, gelatinolytic and caseinolytic activities were suppressed in LT, HT, and PC groups but not in the NC group. The results suggest that ALH-L1005 could be an effective agent for clinical prevention and treatment of periodontitis by inhibiting the gelatinase and collagenase activities, which can detach periodontal ligaments from alveolar bone. PMID:27515267

  18. Efficacy of horse chestnut leaf extract ALH-L1005 as a matrix metalloproteinase inhibitor in ligature-induced periodontitis in canine model.

    PubMed

    Kim, Se Eun; Kim, Tae Hyun; Park, Shin Ae; Kim, Won Tae; Park, Young Woo; Ahn, Jae Sang; Jeong, Manbok; Kim, Min-Young; Seo, Kangmoon

    2017-06-30

    Matrix metalloproteinases (MMPs) are the main proteinases associated with periodontal tissue destruction and remodeling. Therefore, inhibition of host-derived MMPs has a key role in the prevention and reduction of periodontitis progression. Horse chestnut ( Aesculus hippocastanum L.) extracts have been used as treatments for inflammatory disease, traditionally. This study assessed the clinical effect as a MMP inhibitor of horse chestnut leaf extract ALH-L1005 on periodontitis. ALH-L1005 was obtained from horse chestnut leaf and its MMP inhibitory activities estimated. Periodontitis was induced in beagles assigned to 4 groups and medicated for 6 weeks: low dose test (LT; ALH-L1005, 100 mg/kg/day), high dose test (HT; ALH-L1005, 200 mg/kg/day), positive control (PC; doxycycline, 10 mg/kg/day), or negative control (NC; placebo). Before and after administration, clinical indices of the teeth and MMP quantity in gingival tissues using zymography were measured. Clinical conditions of the LT, HT, and PC groups were significantly improved after 6 weeks. In zymographic evaluations, gelatinolytic and caseinolytic activities were suppressed in LT, HT, and PC groups but not in the NC group. The results suggest that ALH-L1005 could be an effective agent for clinical prevention and treatment of periodontitis by inhibiting the gelatinase and collagenase activities, which can detach periodontal ligaments from alveolar bone.

  19. Pigeonholing planetary meteorites: The lessons of misclassification of EET87521 and ALH84001

    NASA Technical Reports Server (NTRS)

    Lindstrom, M. M.; Treiman, A. H.; Mittlefehldt, D. W.

    1994-01-01

    The last few years have provided two noteworthy examples of misclassifications of achondritic meteorites because the samples were new kinds of meteorites from planetary rather than asteroidal parent bodies. Basaltic lunar meteorite EET87521 was misclassified as a eucrite and SNC (martian) orthopyroxenite ALH84001 was misclassified as a diogenite. In classifying meteorites we find what we expect: we pigeonhole meteorites into known categories most of which were derived from the more common asteroidal meteorites. But the examples of EET8752 and ALH84001 remind us that planets are more complex than asteroids and exhibit a wider variety of rock types. We should expect variety in planetary meteorites and we need to know how to recognize them when we have them. Our intent here is to show that our asteroidal perspective is inappropriate for planetary meteorites.

  20. Experimental Shock Decomposition of Siderite and the Origin of Magnetite in Martian Meteorite ALH84001

    NASA Technical Reports Server (NTRS)

    Bell, Mary Sue

    2007-01-01

    Shock recovery experiments to determine whether magnetite could be produced by the decomposition of iron-carbonate were initiated. Naturally occurring siderite was first characterized by electron microprobe (EMP), transmission electron microscopy (TEM), Mossbauer spectroscopy, and magnetic susceptibility measurements to be sure that the starting material did not contain detectable magnetite. Samples were shocked in tungsten-alloy holders (W=90%, Ni=6%, Cu=4%) to further insure that any iron phases in the shock products were contributed by the siderite rather than the sample holder. Each sample was shocked to a specific pressure between 30 to 49 GPa. Previously reported results of TEM analyses on 49 GPa experiments indicated the presence of nano-phase spinel-structured iron oxide. Transformation of siderite to magnetite as characterized by TEM was found in the 49 GPa shock experiment. Compositions of most magnetites are greater than 50% Fe sup(+2) in the octahedral site of the inverse spinel structure. Magnetites produced in shock experiments display the same range of single-domain, superparamagnetic sizes (approx. 50 100 nm), compositions (100% magnetite to 80% magnetite-20% magnesioferrite), and morphologies (equant, elongated, euhedral to subhedral) as magnetites synthesized by Golden et al. (2001) or magnetites grown naturally by MV1 magnetotactic bacteria, and as the magnetites in Martian meteorite ALH84001. Fritz et al. (2005) previously concluded that ALH84001 experienced approx. 32 GPa pressure and a resultant thermal pulse of approx. 100 - 110 C. However, ALH84001 contains evidence of local temperature excursions high enough to 1 melt feldspar, pyroxene, and a silica-rich phase. This 49 GPa experiment demonstrates that magnetite can be produced by the shock decomposition of siderite as a result of local heating to greater than 470 C. Therefore, magnetite in the rims of carbonates in Martian meteorite ALH84001 could be a product of shock devolatilization of

  1. Truncated Hexa-Octahedral Magnetites: Biosignatures in Terrestrial Samples and Martian Meteorite ALH84001

    NASA Technical Reports Server (NTRS)

    Thomas-Keprta, Kathie L.; Clemett, Simon J.; Bazylinski, Dennis A.; Kirschvink, Joseph L.; McKay, David S.; Wentworth, Susan J.; Vali, H.; Gibson, Everett K.

    2001-01-01

    We suggest that the observation of truncated hexa-octahedral magnetites in ALH84001 are both consistent with, and in the absence of terrestrial inorganic analogs, likely formed by biogenic processes. Additional information is contained in the original extended abstract.

  2. Chains of magnetite crystals in the meteorite ALH84001: Evidence of biological origin

    PubMed Central

    Friedmann, E. Imre; Wierzchos, Jacek; Ascaso, Carmen; Winklhofer, Michael

    2001-01-01

    The presence of magnetite crystal chains, considered missing evidence for the biological origin of magnetite in ALH84001 [Thomas-Keprta, K. L., Bazylinski, D. A., Kirschvink, J. L., Clemett, S. J., McKay, D. S., Wentworth, S. J., Vali, H., Gibson, E. K., Jr., & Romanek, C. S. (2000) Geochim. Cosmochim. Acta 64, 4049–4081], is demonstrated by high-power stereo backscattered scanning electron microscopy. Five characteristics of such chains (uniform crystal size and shape within chains, gaps between crystals, orientation of elongated crystals along the chain axis, flexibility of chains, and a halo that is a possible remnant of a membrane around chains), observed or inferred to be present in magnetotactic bacteria but incompatible with a nonbiological origin, are shown to be present. Although it is unlikely that magnetotactic bacteria were ever alive in ALH84001, decomposed remains of such organisms could have been deposited in cracks in the rock while it was still on the surface on Mars. PMID:11226212

  3. Lattice damage and Al-metal precipitation in 2.5 MeV-electron-irradiated AlH3

    NASA Astrophysics Data System (ADS)

    Zogal, O. J.; Vajda, P.; Beuneu, F.; Pietraszko, A.

    1998-04-01

    AlH3 powder was bombarded with energetic electrons at 20 K and at room temperature and investigated by EPR, NMR, X-ray diffractometry, and microwave dielectric-constant measurements. The EPR spectra of the irradiated powder and of a selected single crystal cuboid of ˜ {10^{ - 1}} mm edge show a complex asymmetric line centered at g = 2.009, with a Curie-like temperature dependence, attributed to radiation-induced color centers and/or their agglomerates. At the same time, the grains, which have become shiny black after irradiation, exhibit an increase of both the real and the imaginary part of ɛ. 27Al-NMR spectra of the irradiated powder present a Knight-shifted line at 1600(50) ppm, close to the position of bulk metallic Al, and corresponding to a concentration of c(Al) ˜ {10^{ - 1}}. In addition, the main hydride line differs from that before irradiation, demonstrating an alteration of environmental symmetry. The irradiation induces also a change in shape and width of the 1H-NMR line, another indication of symmetry change in the lattice. Finally, a refined X-ray single-crystal structure analysis of the irradiated cuboid indicates a change of structure from trigonal R -3 c to R -3, with a loss of mirror symmetry for the two Al sites caused by the introduction of Al-defects in the vicinity of one of them.

  4. The Carbonates in ALH 84001 Record the Evolution of the Martian Atmosphere Through Multiple Formation Events

    NASA Technical Reports Server (NTRS)

    Shaheen, R.; Niles, P. B.; Corrgan, C.

    2012-01-01

    Current Martian conditions restrict the presence of liquid water due to low temperatures (approx 210K), a thin atmosphere (approx 7mb), and intense UV radiation. However, past conditions on Mars may have been different with the possibility that the ancient Martian climate was warm and wet with a dense CO2 atmosphere. The cycling of carbon on Mars through atmospheric CO2 and carbonate minerals is critical for deciphering its climate history. In particular stable isotopes contained in carbonates can provide information of their origin and formation environment as well as possibly hinting at the composition of global reservoirs such as atmospheric CO2. Martian meteorite ALH 84001 contains widely studied carbonate rosettes that have been dated to approx. 3.9 Ga and have been used to interpret climatic conditions present at that time. However, there is mount-ing evidence for multiple episodes of carbonate formation in ALH 84001 with potentially distinct isotopic compositions. This study seeks to tease out these different carbonate assemblages using stepped phosphoric acid dissolution and analysis of carbon and triple oxygen stable isotopes. In addition, we report SIMS analyses of the delta O-18 several petrographically unusual carbonate phases in the meteorite.

  5. Biosignatures in the Recrystallized Shock Melt Pocket of ALH-77005 Shergottite — Clues to Martian Life

    NASA Astrophysics Data System (ADS)

    Gyollai, I.; Polgári, M.; Bérczi, Sz.; Gucsik, A.; Pál-Molnár, E.

    2017-11-01

    In the spinifex textured, recrystallized shock melt portion in ALH 77005 shergottite mineralized microbially produced texture (MMPT) - in form of pearl necklace-like, vermiform inner signatures - was measured, which we propose to have Martian origin.

  6. Ca-,Al-rich inclusions in the unique chondrite ALH85085 - Petrology, chemistry, and isotopic compositions

    NASA Technical Reports Server (NTRS)

    Kimura, Makoto; El-Goresy, Ahmed; Palme, Herbert; Zinner, Ernst

    1993-01-01

    A comprehensive study is performed for the Ca-,Al-rich inclusions (CAIs) in the unique chondrite ALH85085. The ALH85085 inclusions are smaller (5-80 microns) and more refractory than their counterparts in carbonaceous chondrites. The study includes 42 inclusions for petrography and mineralogy, 15 for bulk major and minor element chemical composition, six for Mg-Al isotopic systematics, 10 for Ca isotopes, nine for Ti isotopes, and six for trace element abundances. In addition, oxygen-isotopic compositions were determined in minerals from a single inclusion. No correlation is found between mineralogy, major element chemistry, and trace element abundances. It is further shown that the high-temperature geochemical behavior of ultrarefractory trace elements is decoupled from that of the major elements Ca and Ti (Ti is correlated with the relatively volatile elements Nb and Yb) implying that perovskite is of only minor importance as carrier of ultrarefractories.

  7. ALH85085: a unique volatile-poor carbonaceous chondrite with possible implications for nebular fractionation processes

    USGS Publications Warehouse

    Grossman, J.N.; Rubin, A.E.; MacPherson, G.J.

    1988-01-01

    Allan Hills 85085 is a unique chondrite with affinities to the Al Rais-Renazzo clan of carbonaceous chondrites. Its constituents are less than 50 ??m in mean size. Chondrules and microchondrules of all textures are present; nonporphyritic chondrules are unusually abundant. The mean compositions of porphyritic, nonporphyritic and barred olivine chondrules resemble those in ordinary chondrites except that they are depleted in volatile elements. Ca-, Al-rich inclusions are abundant and largely free of nebular alteration; they comprise types similar to those in CM and CO chondrites, as well as unique types. Calcium dialuminate occurs in several inclusions. Metal, silicate and sulfide compositions are close to those in CM-CO chondrites and Al Rais and Renazzo. C1-chondrite clasts and metal-rich "reduced" clasts are present, but opaque matrix is absent. Siderophile abundances in ALH85085 are extremely high (e.g., Fe Si = 1.7 ?? solar), and volatiles are depleted (e.g., Na Si = 0.25 ?? solar, S Si = 0.03 ?? solar). Nonvolatile lithophile abundances are similar to those in Al Rais, Renazzo, and CM and CO chondrites. ALH85085 agglomerated when temperatures in the nebula were near 1000 K, in the same region where Renazzo, Al Rais and the CI chondrites formed. Agglomeration of high-temperature material may thus be a mechanism by which the fractionation of refractory lithophiles occurred in the nebula. Chondrule formation must have occurred at high temperatures when clumps of precursors were small. After agglomeration, ALH85085 was annealed and lightly shocked. C1 and other clasts were subsequently incorporated during late-stage brecciation. ?? 1988.

  8. Hydrothermal Origin for Carbonate Globules in Martian Meteorite ALH84001: A Terrestrial Analogue from Spitsbergen (Norway)

    NASA Technical Reports Server (NTRS)

    Treiman, Allan H.; Amundsen, Hans E. F.; Blake, David F.; Bunch, Ted

    2002-01-01

    Carbonate minerals in the ancient Martian meteorite ALH84001 are the only known solid phases that bear witness to the processing of volatile and biologically critical compounds (CO2, H2O) on early Mars. Similar carbonates have been found in xenoliths and their host basalts from Quaternary volcanic centers in northern Spitsbergen (Norway). These carbonates were deposited by hot (i.e., hydrothermal) waters associated with the volcanic activity. By analogy with the Spitsbergen carbonates, the ALH84001 carbonates were probably also deposited by hot water. Hydrothermal activity was probably common and widespread on Early Mars, which featured abundant basaltic rocks, water as ice or liquid, and heat from volcanos and asteroid impacts. On Earth, descendants of the earliest life forms still prefer hydrothermal environments, which are now shown to have been present on early Mars.

  9. Thermal Decomposition of an Impure (Roxbury) Siderite: Relevance to the Presence of Chemically Pure Magnetite Crystals in ALH84001 Carbonate Disks

    NASA Technical Reports Server (NTRS)

    McKay, D.S.; Gibson, E.K.; Thomas-Keprta, K.L.; Clemett, S.J.; Wentworth, S.J.

    2009-01-01

    The question of the origin of nanophase magnetite in Martian meteorite ALH84001 has been widely debated for nearly a decade. Golden et al. have reported producing nearly chemically pure magnetite from thermal decomposition of chemically impure siderite [(Fe, Mg, Mn)CO3]. This claim is significant for three reasons: first, it has been argued that chemically pure magnetite present in the carbonate disks in Martian meteorite ALH84001 could have formed by the thermal decomposition of the impure carbonate matrix in which they are embedded; second, the chemical purity of magnetite has been previously used to identify biogenic magnetite; and, third, previous studies of thermal decomposition of impure (Mg,Ca,Mn)-siderites, which have been investigated under a wide variety of conditions by numerous researchers, invariably yields a mixed metal oxide phase as the product and not chemically pure magnetite. The explanation for this observation is that these siderites all possess the same crystallographic structure (Calcite; R3c) so solid solutions between these carbonates are readily formed and can be viewed on an atomic scale as two chemically different but structurally similar lattices.

  10. Submicron magnetite grains and carbon compounds in Martian meteorite ALH84001: inorganic, abiotic formation by shock and thermal metamorphism.

    PubMed

    Treiman, Allan H

    2003-01-01

    Purported biogenic features of the ALH84001 Martian meteorite (the carbonate globules, their submicron magnetite grains, and organic matter) have reasonable inorganic origins, and a comprehensive hypothesis is offered here. The carbonate globules were deposited from hydrothermal water, without biological mediation. Thereafter, ALH84001 was affected by an impact shock event, which raised its temperature nearly instantaneously to 500-700K, and induced iron-rich carbonate in the globules to decompose to magnetite and other minerals. The rapidity of the temperature increase caused magnetite grains to nucleate in abundance; hence individual crystals were very small. Nucleation and growth of magnetite crystals were fastest along edges and faces of the precursor carbonate grains, forcing the magnetite grains to be platy or elongated, including the "truncated hexa-octahedra" shape. ALH84001 had formed at some depth within Mars where the lithostatic pressure was significantly above that of Mars' surface. Also, because the rock was at depth, the impact heat dissipated slowly. During this interval, magnetite crystals approached chemical equilibria with surrounding minerals and gas. Their composition, nearly pure Fe(3)O(4), reflects those of equilibria; elements that substitute into magnetite are either absent from iron-rich carbonate (e.g., Ti, Al, Cr), or partitioned into other minerals during magnetite formation (Mg, Mn). Many microstructural imperfections in the magnetite grains would have annealed out as the rock cooled. In this post-shock thermal regime, carbon-bearing gas from the decomposition of iron carbonates reacted with water in the rock (or from its surroundings) to produce organic matter via Fischer-Tropschlike reactions. Formation of such organic compounds like polycyclic aromatic hydrocarbons would have been catalyzed by the magnetite (formation of graphite, the thermochemically stable phase, would be kinetically hindered).

  11. Ab initio studies on Al(+)(H(2)O)(n), HAlOH(+)(H(2)O)(n-1), and the size-dependent H(2) elimination reaction.

    PubMed

    Siu, Chi-Kit; Liu, Zhi-Feng; Tse, John S

    2002-09-11

    We report computational studies on Al(+)(H(2)O)(n), and HAlOH(+)(H(2)O)(n-1), n = 6-14, by the density functional theory based ab initio molecular dynamics method, employing a planewave basis set with pseudopotentials, and also by conventional methods with Gaussian basis sets. The mechanism for the intracluster H(2) elimination reaction is explored. First, a new size-dependent insertion reaction for the transformation of Al(+)(H(2)O)(n), into HAlOH(+)(H(2)O)(n-1) is discovered for n > or = 8. This is because of the presence of a fairly stable six-water-ring structure in Al(+)(H(2)O)(n) with 12 members, including the Al(+). This structure promotes acidic dissociation and, for n > or = 8, leads to the insertion reaction. Gaussian based BPW91 and MP2 calculations with 6-31G* and 6-31G** basis sets confirmed the existence of such structures and located the transition structures for the insertion reaction. The calculated transition barrier is 10.0 kcal/mol for n = 9 and 7.1 kcal/mol for n = 8 at the MP2/6-31G** level, with zero-point energy corrections. Second, the experimentally observed size-dependent H(2) elimination reaction is related to the conformation of HAlOH(+)(H(2)O)(n-1), instead of Al(+)(H(2)O)(n). As n increases from 6 to 14, the structure of the HAlOH(+)(H(2)O)(n-1) cluster changes into a caged structure, with the Al-H bond buried inside, and protons produced in acidic dissociation could then travel through the H(2)O network to the vicinity of the Al-H bond and react with the hydride H to produce H(2). The structural transformation is completed at n = 13, coincident approximately with the onset of the H(2) elimination reaction. From constrained ab initio MD simulations, we estimated the free energy barrier for the H(2) elimination reaction to be 0.7 eV (16 kcal/mol) at n = 13, 1.5 eV (35 kcal/mol) at n = 12, and 4.5 eV (100 kcal/mol) at n = 8. The existence of transition structures for the H(2) elimination has also been verified by ab initio calculations

  12. Hydrogeological Interpretation of Candidate Origin Sites for Martian Meteorite ALH84001

    NASA Technical Reports Server (NTRS)

    Gulick, Virginia C.; McKay, Chris; Cuzzi, Jeffrey N. (Technical Monitor)

    1996-01-01

    Barlow (this meeting) has identified two potential source craters for the martian meteorite ALH84001. The craters are at 11.7 deg S, 243.3 deg W (Mare Tyrrhenum site) and 14.0 deg S, 343.5 deg W (Sinus Sabaeus site). As noted by Barlow, both craters lie in the heavily cratered terrain (HCT) and are adjacent to fluvial valleys, Here I explore the fluvial history of these areas based upon the surrounding valley morphology. The most prominent valley network at the Sabaeus site is Evros Vallis. This wide, flat-floored valley is approximately 600 km long with an average width of 2.5 km and a depth of 220 m. The eroded volume of the entire Evros network is approximately 6 x 10(exp 11) cc. This is typical for networks located in the heavily cratered terrain (e.g. Warrego and Parana Valles). Evros is also an isolated valley system. No similar networks are found in the surrounding terrain. Thus it is unlikely that Evros formed as a result of widespread rainfall. A localized water source, such as discharge of a hydrothermal system or localized melting of snowfall, seems more consistent Previous modeling has demonstrated that only hydrothermal systems associated with high permeability subsurfaces can discharge sufficient water to form a valley network. The bulk of the discharge from such systems is consequently low temperature, slightly heated water Precipitation of calcium carbonate by low temperature fluids is consistent with most interpretations of the geochemistry of ALH84001. Available imagery at the Tyrrhenum site is of lesser quality. While eroded units of the HCT are nearby, there are no comparable well developed valley networks at this site. Erosion is instead manifested predominantly as gullies on slopes. This style of erosion suggests that water was not present at this site for the length of time as at the more integrated Sabaeus site. The superposition of fluidized ejecta blankets suggests however that ground water or ground ice was still present at this locality

  13. Formation of "Chemically Pure" Magnetite from Mg-Fe-Carbonates Implications for the Exclusively Inorganic Origin of Magnetite and Sulfides in Martian Meteorite ALH84001

    NASA Technical Reports Server (NTRS)

    Golden, D. C.; Ming, Douglas W.; Lauer, H. V., Jr.; Morris, R. V.; Trieman, A. H.; McKay, G. A.

    2006-01-01

    Magnetite and sulfides in the black rims of carbonate globules in Martian meteorite ALH84001 have been studied extensively because of the claim by McKay et al. that they are biogenic in origin. However, exclusively inorganic (abiotic) processes are able to account for the occurrence of carbonate-sulfide-magnetite assemblages in the meteorite. We have previously precipitated chemically zoned and sulfide-bearing carbonate globules analogous to those in ALH84001 (at less than or equal to 150 C) from multiple fluxes of variable-composition Ca-Mg-Fe-CO2-S-H2O solutions. Brief heating of precipitated globules to approx. 470 C produced magnetite and pyrrhotite within the globules by thermal decomposition of siderite and pyrite, respectively. We have also shown that morphology of magnetite formed by inorganic thermal decomposition of Fe-rich carbonate is similar to the morphology of so-called biogenic magnetite in the carbonate globules of ALH84001. Magnetite crystals in the rims of carbonate globules in ALH84001 are chemically pure [Note: "Chemically pure" is defined here as magnetite with Mg at levels comparable or lower than Mg detected by [8] in ALH84001 magnetite]. A debate continues on whether or not chemically pure magnetite can form by the thermal decomposition of mixed Mg-Fe-carbonates that have formed under abiotic conditions. Thomas-Keprta et al. argue that it is not possible to form Mg-free magnetite from Mg-Fe-carbonate based on thermodynamic data. We previously suggested that chemically pure magnetite could form by the thermal decomposition of relatively pure siderite in the outer rims of the globules. Mg-Fe-carbonates may also thermally decompose under conditions conducive for formation of chemically pure magnetite. In this paper we show through laboratory experiments that chemically pure magnetite can form by an inorganic process from mixed Mg-Fe-carbonates.

  14. A Hypothesis for the Abiotic and Non-Martian Origins of Putative Signs of Ancient Martian Life in ALH84001

    NASA Technical Reports Server (NTRS)

    Treiman, Allan H.

    2001-01-01

    Putative evidence of martian life in ALH84001 can be explained by abiotic and non-martian processes consistent with the meteorite's geological history. Additional information is contained in the original extended abstract.

  15. Covariant C and O Isotope Trends in Some Terrestrial Carbonates and ALH 84001: Possible Linkage Through Similar Formation Processes

    NASA Technical Reports Server (NTRS)

    Volk, Kathryn E.; Niles, Paul B.; Socki, Richard A.

    2011-01-01

    Carbonate minerals found on the surface of Mars and in martian meteorites indicate that liquid water has played a significant role in the planet's history. These findings have raised questions regarding the history of the martian hydrosphere and atmosphere as well as the possibility of life. Sunset Crater, Arizona is a dry environment with relatively high evaporation and brief periods of precipitation. This environment resembles Mars and may make Sunset Crater a good analog to martian carbonates. In this study we sought to identify discrete micro-scale isotopic variation within the carbonate crusts in Sunset Crater to see if they resembled the micro-scale isotope variation found in ALH 84001 carbonates. Sunset Crater carbonate formation may be used as a martian analog and ultimately provide insight into carbonate formation in ALH 84001.

  16. Cubic and orthorhombic structures of aluminum hydride Al H3 predicted by a first-principles study

    NASA Astrophysics Data System (ADS)

    Ke, Xuezhi; Kuwabara, Akihide; Tanaka, Isao

    2005-05-01

    The most stable structure of aluminum hydride AlH3 is believed to be a hexagonal symmetry. However, using the density functional theory, we have identified two more stable structures for the AlH3 with the cubic and orthorhombic symmetries. Based on the quasiharmonic approximation, the cubic and orthorhombic AlH3 are almost degenerate when the zero-point energies are included. The geometric and electronic structures, the phonon, and the thermodynamic properties for the hexagonal, cubic, and orthorhombic AlH3 have been studied by means of density functional theory and direct ab initio force constant approach. The calculated electronic structures, phonon density of states, and thermodynamic functions [including S(T) and H(T)-H(0) ] for the three hydrides are similar. The results show that these three hydrides have negative enthalpies of formation, but positive free energies of formation. This conclusion is the same as that made by Wolverton for the hexagonal AlH3 [Phys. Rev. B 69, 144109 (2004)]. The thermodynamic properties indicate that the orthorhombic and cubic AlH3 should be more difficult to dissociate than the hexagonal AlH3 .

  17. A low temperature transfer of ALH84001 from Mars to Earth.

    PubMed

    Weiss, B P; Kirschvink, J L; Baudenbacher, F J; Vali, H; Peters, N T; Macdonald, F A; Wikswo, J P

    2000-10-27

    The ejection of material from Mars is thought to be caused by large impacts that would heat much of the ejecta to high temperatures. Images of the magnetic field of martian meteorite ALH84001 reveal a spatially heterogeneous pattern of magnetization associated with fractures and rock fragments. Heating the meteorite to 40 degrees C reduces the intensity of some magnetic features, indicating that the interior of the rock has not been above this temperature since before its ejection from the surface of Mars. Because this temperature cannot sterilize most bacteria or eukarya, these data support the hypothesis that meteorites could transfer life between planets in the solar system.

  18. AMINO ACID ANALYSES OF THE ANTARCTIC CM2 METEORITES ALH 83100 AND LEW 90500 USING LIQUID CHROMATOGRAPHY-TIME OF FLIGHT-MASS SPECTROMETRY

    NASA Technical Reports Server (NTRS)

    Glavin, D. P.; Dworkin, J. P.; Aubrey, A.; Botta, O.; Doty, J. H., III; Bada, J. L.

    2001-01-01

    The investigation of organic compounds in primitive carbonaceous meteorites provides a record of the chemical processes that occurred in the early solar system. In particular, amino acids have been shown to be potential indicators in tracing the nature of carbonaceous chondrite parent bodies [ 13. The delivery of amino acids by carbonaceous chondrites to the early Earth could have been any important source of the Earth's prebiotic organic inventory [2]. Over 80 different amino acids have been detected in the Murchison CM2 meteorite, most of them completely non-existent in the terrestrial biosphere [3]. We have optimized a new liquid chromatography-time-of-flight-mass spectrometry (LC-ToF-MS) technique coupled with OPAMAC derivatization in order to detect amino acids in meteorite extracts by UV fluorescence and exact mass simultaneously. The detection limit of the LC-ToF-MS instrument for amino acids is at least 3 orders of magnitude lower than traditional GC-MS techniques. Here we report on the first analyses of amino acids and their enantiomeric abundances in the CM2 carbonaceous meteorites ALH 83100, LEW 90500, and Murchison using this new LC-ToF-MS instrument configuration. Amino acid analyses of any kind for the CM meteorite ALH 83100 have not previously been reported.

  19. Magnetite Formation from Thermal Decomposition of Siderite: Implications for Inorganic Magnetite Formation in Martian Meteorite ALH84001

    NASA Technical Reports Server (NTRS)

    Morris, RIchard V.

    2002-01-01

    A biogenic mechanism for formation of a subpopulation magnetite in Martian meteorite ALH84001 has been suggested [McKay et al., 1996; Thomas-Keprta, et al., 2000]. We are developing experimental evidence for an alternating working hypothesis, that the subpopulation was produced inorganically by the thermal decomposition of siderite [Golden et al., 2000].

  20. Cryogenic Calcite: A Morphologic and Isotopic Analog to the ALH84001 Carbonates

    NASA Technical Reports Server (NTRS)

    Niles, P. B.; Leshin, L. A.; Socki, R. A.; Guan, Y.; Ming, D. W.; Gibson, E. K.

    2004-01-01

    Martian meteorite ALH84001 carbonates preserve large and variable microscale isotopic compositions, which in some way reflect their formation environment. These measurements show large variations (>20%) in the carbon and oxygen isotopic compositions of the carbonates on a 10-20 micron scale that are correlated with chemical composition. However, the utilization of these data sets for interpreting the formation conditions of the carbonates is complex due to lack of suitable terrestrial analogs and the difficulty of modeling under non-equilibrium conditions. Thus, the mechanisms and processes are largely unknown that create and preserve large microscale isotopic variations in carbonate minerals. Experimental tests of the possible environments and mechanisms that lead to large microscale isotopic variations can help address these concerns. One possible mechanism for creating large carbon isotopic variations in carbonates involves the freezing of water. Carbonates precipitate during extensive CO2 degassing that occurs during the freezing process as the fluid s decreasing volume drives CO2 out. This rapid CO2 degassing results in a kinetic isotopic fractionation where the CO2 gas has a much lighter isotopic composition causing an enrichment of 13C in the remaining dissolved bicarbonate. This study seeks to determine the suitability of cryogenically formed carbonates as analogs to ALH84001 carbonates. Specifically, our objective is to determine how accurately models using equilibrium fractionation factors approximate the isotopic compositions of cryogenically precipitated carbonates. This includes determining the accuracy of applying equilibrium fractionation factors during a kinetic process, and determining how isotopic variations in the fluid are preserved in microscale variations in the precipitated carbonates.

  1. High Resolution Chemical Study of ALH84001

    NASA Technical Reports Server (NTRS)

    Conrad, Pamela G.; Douglas, Susanne; Kuhlman, Kimberly R.

    2001-01-01

    We have studied the chemistry of a sample of the SNC meteorite ALH84001 using an environmental scanning electron microscope (ESEM) with an energy dispersive chemical analytical detector and a focused ion beam secondary ion mass spectrometer (FIB-SIMS). Here we present the chemical data, both spectra and images, from two techniques that do not require sample preparation with a conductive coating, thus eliminating the possibility of preparation-induced textural artifacts. The FIB-SIMS instrument includes a column optimized for SEM with a quadrupole type mass spectrometer. Its spatial and spectral resolution are 20 nm and 0.4 AMU, respectively. The spatial resolution of the ESEM for chemical analysis is about 100 nm. Limits of detection for both instruments are mass dependent. Both the ESEM and the FIB-SIMS instrument revealed contrasting surficial features; crumbled, weathered appearance of the matrix in some regions as well as a rather ubiquitous presence of euhedral halite crystals, often associated with cracks or holes in the surface of the rock. Other halogen elements present in the vicinity of the NaCl crystals include K and Br. In this report, elemental inventories are shown as mass spectra and as X-ray maps.

  2. Statistical Analyses Comparing Prismatic Magnetite Crystals in ALH84001 Carbonate Globules with those from the Terrestrial Magnetotactic Bacteria Strain MV-1

    NASA Technical Reports Server (NTRS)

    Thomas-Keprta, Kathie L.; Clemett, Simon J.; Bazylinski, Dennis A.; Kirschvink, Joseph L.; McKay, David S.; Wentworth, Susan J.; Vali, H.; Gibson, Everett K.

    2000-01-01

    Here we use rigorous mathematical modeling to compare ALH84001 prismatic magnetites with those produced by terrestrial magnetotactic bacteria, MV-1. We find that this subset of the Martian magnetites appears to be statistically indistinguishable from those of MV-1.

  3. ACFER 182/207/214 A Metal-rich, Volatile-poor Chondritic Meteorite, Similar to ALH85085

    NASA Astrophysics Data System (ADS)

    Palme, H.; Spettel, B.

    1992-07-01

    The unique Antarctic meteorite ALH85085 was the first chondritic meteorite to contain a significant excess of metallic Fe and associated siderophile elements (e.g., Grossman et al. 1988, Wasson and Kallemeyn 1990). Recently three Sahara meteorites, Acfer 182/207/214, apparently belonging to the same fall, were shown to be chemically and mineralogically very similar to ALHA85085, although minor textural differences appear to exclude a common origin with ALH85085. A mineralogical description and chemical composition of Acfer182/207/214 (henceforth ACFER182) are given in Bischoff et al. (1992). These authors suggested designating ALH85085 and ACFER182 as HH-chondrites reflecting high total Fe and high metal. The Fe/Mg-ratio of ACFER182 is 1.7 times that of CI-chondrites. All metals more refractory than Fe have similar enrichment factors, i.e., non-volatile metals occur in chondritic proportions, except for a slightly lower W enrichment. Metals more volatile than Fe are strongly depleted, with the depletion sequence closely following decreasing condensation temperatures. CI-normalized abundances are: Fe(1.92), Au(1.33), As(1.04), Cu(0.62), Ga(0.38), and the chalcophile Se(0.17). Lithophiles, more refractory than Mg, but including Mg and Cr, also occur in CI-abundance ratios (e.g., Sc/Mg in ACFER182 is 1.05xCI), although their absolute abundances are lower than those of metals. More volatile lithophile elements (Mn, Zn, etc.) decrease in abundance with decreasing condensation temperatures, just as the metals. The parallel (metal and silicate) decrease in moderately volatile element abundances with condensation temperatures suggests a similar nebular history for metal and silicate and is readily understood in a model where nebular gas is continually removed during condensation (Wasson and Chou 1974). Actual mixing of silicate and metal, i.e., agglomeration of silicate and metal grains in non-chondritic proportions (with 70% metal excess) could have occurred at relatively

  4. Origins of Magnetite Nanocrystals in Martian Meteorite ALH84001

    NASA Technical Reports Server (NTRS)

    Thomas-Keprta, Kathie L.; Clemett, Simon J.; Mckay, David S.; Gibson, Everett K.; Wentworth, Susan J.

    2009-01-01

    The Martian meteorite ALH84001 preserves evidence of interaction with aqueous fluids while on Mars in the form of microscopic carbonate disks. These carbonate disks are believed to have precipitated 3.9 Ga ago at beginning of the Noachian epoch on Mars during which both the oldest extant Martian surfaces were formed, and perhaps the earliest global oceans. Intimately associated within and throughout these carbonate disks are nanocrystal magnetites (Fe3O4) with unusual chemical and physical properties, whose origins have become the source of considerable debate. One group of hypotheses argues that these magnetites are the product of partial thermal decomposition of the host carbonate. Alternatively, the origins of mag- netite and carbonate may be unrelated; that is, from the perspective of the carbonate the magnetite is allochthonous. For example, the magnetites might have already been present in the aqueous fluids from which the carbonates were believed to have been deposited. We have sought to resolve between these hypotheses through the detailed characterized of the compo- sitional and structural relationships of the carbonate disks and associated magnetites with the orthopyroxene matrix in which they are embedded. Extensive use of focused ion beam milling techniques has been utilized for sample preparation. We then compared our observations with those from experimental thermal decomposition studies of sideritic carbonates under a range of plausible geological heating scenarios. We conclude that the vast majority of the nanocrystal magnetites present in the car- bonate disks could not have formed by any of the currently proposed thermal decomposition scenarios. Instead, we find there is considerable evidence in support of an alternative allochthonous origin for the magnetite unrelated to any shock or thermal processing of the carbonates.

  5. Bacterial mineralization patterns in basaltic aquifers: implications for possible life in martian meteorite ALH84001

    NASA Technical Reports Server (NTRS)

    Thomas-Keprta, K. L.; McKay, D. S.; Wentworth, S. J.; Stevens, T. O.; Taunton, A. E.; Allen, C. C.; Coleman, A.; Gibson, E. K. Jr; Romanek, C. S.

    1998-01-01

    To explore the formation and preservation of biogenic features in igneous rocks, we have examined the organisms in experimental basaltic microcosms using scanning and transmission electron microscopy. Four types of microorganisms were recognized on the basis of size, morphology, and chemical composition. Some of the organisms mineralized rapidly, whereas others show no evidence of mineralization. Many mineralized cells are hollow and do not contain evidence of microstructure. Filaments, either attached or no longer attached to organisms, are common. Unattached filaments are mineralized and are most likely bacterial appendages (e.g., prosthecae). Features similar in size and morphology to unattached, mineralized filaments are recognized in martian meteorite ALH84001.

  6. FTIR Analysis of Water in Pyroxene and Plagioclase in ALH 84001 and Nakhlites

    NASA Technical Reports Server (NTRS)

    Peslier, A. H.; Cintala, M. J.; Montes, R.; Cardenas, F.

    2016-01-01

    with crustal reservoirs or hydrothermal fluids. Here, nominally anhydrous minerals (pyroxene, olivine, plagioclase, or maskelynite) in orthopyroxenite ALH 84001 and selected nakhlites are analyzed for water and major elements, in order to determine 1) whether they contain any water; 2) if they do, what controls its distribution (crystallization, degassing, hydrothermal or impact processes); and 3) if any of these measurements can be used to infer the water contents of the parent magma and their mantle sources. A shock-reverberation experiment was also performed on terrestrial orthopyroxenes (opx) to simulate the heavily shocked conditions of ALH 84001 (> 31 GPa [17]).

  7. Bacterial mineralization patterns in basaltic aquifers: Implications for possible life in Martian meteorite ALH84001

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

    Thomas-Keprta, K.L.; Wentworth, S.J.; Allen, C.C.

    To explore the formation and preservation of biogenic features in igneous rocks, the authors have examined the organisms in experimental basaltic microcosms using scanning and transmission electron microscopy. Four types of microorganisms were recognized on the basis of size, morphology, and chemical composition. Some of the organisms mineralized rapidly, whereas others show no evidence of mineralization. Many mineralized cells are hollow and do not contain evidence of microstructure. Filaments, either attached or no longer attached to organisms, are common. Unattached filaments are mineralized and are most likely bacterial appendages (e.g., prosthecae). Features similar in size and morphology to unattached, mineralizedmore » filaments are recognized in martial meteorite ALH84001.« less

  8. Sn2+-Stabilization in MASnI3 perovskites by superhalide incorporation.

    PubMed

    Xiang, Junxiang; Wang, Kan; Xiang, Bin; Cui, Xudong

    2018-03-28

    Sn-based hybrid halide perovskites are a potential solution to replace Pb and thereby reduce Pb toxicity in MAPbI 3 perovskite-based solar cells. However, the instability of Sn 2+ in air atmosphere causes a poor reproducibility of MASnI 3 , hindering steps towards this goal. In this paper, we propose a new type of organic metal-superhalide perovskite of MASnI 2 BH 4 and MASnI 2 AlH 4 . Through first-principles calculations, our results reveal that the incorporation of BH 4 and AlH 4 superhalides can realize an impressive enhancement of oxidation resistance of Sn 2+ in MASnI 3 perovskites because of the large electron transfer between Sn 2+ and [BH 4 ] - /[AlH 4 ] - . Meanwhile, the high carrier mobility is preserved in these superhalide perovskites and only a slight decrease is observed in the optical absorption strength. Our studies provide a new path to attain highly stable performance and reproducibility of Sn-based perovskite solar cells.

  9. The origin of organic matter in the Martian meteorite ALH84001.

    PubMed

    Becker, L; Popp, B; Rust, T; Bada, J L

    1999-01-01

    Stable carbon isotope measurements of the organic matter associated with the carbonate globules and the bulk matrix material in the ALH84001 Martian meteorite indicate that two distinct sources are present in the sample. The delta 13C values for the organic matter associated with the carbonate globules averaged -26% and is attributed to terrestrial contamination. In contrast, the delta 13C values for the organic matter associated with the bulk matrix material yielded a value of -15%. The only common carbon sources on the Earth that yield similar delta 13C values, other then some diagenetically altered marine carbonates, are C4 plants. A delta 13C value of -15%, on the other hand, is consistent with a kerogen-like component, the most ubiquitous form of organic matter found in carbonaceous chondrites such as the Murchison meteorite. Examination of the carbonate globules and bulk matrix material using laser desorption mass spectrometry (LDMS) indicates the presence of a high molecular weight organic component which appears to be extraterrestrial in origin, possibly derived from the exogenous delivery of meteoritic or cometary debris to the surface of Mars.

  10. The origin of organic matter in the Martian meteorite ALH84001.

    PubMed

    Becker, L; Popp, B; Rust, T; Bada, J L

    1999-03-30

    Stable carbon isotope measurements of the organic matter associated with the carbonate globules and the bulk matrix material in the ALH84001 Martian meteorite indicate that two distinct sources are present in the sample. The delta 13C values for the organic matter associated with the carbonate globules averaged -26% and is attributed to terrestrial contamination. In contrast, the delta 13C values for the organic matter associated with the bulk matrix material yielded a value of -15%. The only common sources of carbon on the Earth that yield similar delta 13C values, other then some diagenetically altered marine carbonates, are C4 plants. A delta 13C value of -15%, on the other hand, is consistent with a kerogen-like component, the most ubiquitous form of organic matter found in carbonaceous chondrites such as the Murchison meteorite. Examination of the carbonate globules and bulk matrix material using laser desorption mass spectrometry (LDMS) indicates the presence of a high molecular weight organic component which appears to be extraterrestrial in origin, possibly derived from the exogenous delivery, of meteoritic or cometary debris to the surface of Mars.

  11. Search for Past Life on Mars: Possible Relict Biogenic Activity in Martian Meteorite ALH84001

    NASA Technical Reports Server (NTRS)

    McKay, David S.; Gibson, Everett K., Jr.; Thomas-Keprta, Kathie L.; Vali, Hojatollah; Romanek, Christopher S.; Clemett, Simon J.; Chillier, Xavier D. F.; Maechling, Claude R.; Zare, Richard N.

    1996-01-01

    Fresh fracture surfaces of the martian meteorite ALH84001 contain abundant polycyclic aromatic hydrocarbons (PAHs). These fresh fracture surfaces also display carbonate globules. Contamination studies suggest the PAHs are indigenous to the meteorite. High resolution scanning and transmission electron microscopy study of surface textures and internal structures of selected carbonate globules show that the globules contain fine-grained, secondary phases of single-domain magnetite and Fe-monosulfides. The carbonate globules are similar in texture and size to some terrestrial bacterially induced carbonate precipitates. Although inorganic formation is possible, formation of the globules by biogenic processes could explain many of the observed features including the PAHs. The PAHs, the carbonate globules, and their associated secondary mineral phases and textures could thus be fossil remains of a past martian biota.

  12. Sn2+—Stabilization in MASnI3 perovskites by superhalide incorporation

    NASA Astrophysics Data System (ADS)

    Xiang, Junxiang; Wang, Kan; Xiang, Bin; Cui, Xudong

    2018-03-01

    Sn-based hybrid halide perovskites are a potential solution to replace Pb and thereby reduce Pb toxicity in MAPbI3 perovskite-based solar cells. However, the instability of Sn2+ in air atmosphere causes a poor reproducibility of MASnI3, hindering steps towards this goal. In this paper, we propose a new type of organic metal-superhalide perovskite of MASnI2BH4 and MASnI2AlH4. Through first-principles calculations, our results reveal that the incorporation of BH4 and AlH4 superhalides can realize an impressive enhancement of oxidation resistance of Sn2+ in MASnI3 perovskites because of the large electron transfer between Sn2+ and [BH4]-/[AlH4]-. Meanwhile, the high carrier mobility is preserved in these superhalide perovskites and only a slight decrease is observed in the optical absorption strength. Our studies provide a new path to attain highly stable performance and reproducibility of Sn-based perovskite solar cells.

  13. Al6H18: A baby crystal of γ-AlH3

    NASA Astrophysics Data System (ADS)

    Kiran, B.; Kandalam, Anil K.; Xu, Jing; Ding, Y. H.; Sierka, M.; Bowen, K. H.; Schnöckel, H.

    2012-10-01

    Using global-minima search methods based on the density functional theory calculations of (AlH3)n (n = 1-8) clusters, we show that the growth pattern of alanes for n ≥ 4 is dominated by structures containing hexa-coordinated Al atoms. This is in contrast to the earlier studies where either linear or ring structures of AlH3 were predicted to be the preferred structures in which the Al atoms can have a maximum of five-fold coordination. Our calculations also reveal that the Al6H18 cluster, with its hexa-coordination of the Al atoms, resembles the unit-cell of γ-AlH3, thus Al6H18 is designated as the "baby crystal." The fragmentation energies of the (AlH3)n (n = 2-8) along with the dimerization energies for even n clusters indicate an enhanced stability of the Al6H18 cluster. Both covalent (hybridization) and ionic (charge) contribution to the bonding are the driving factors in stabilizing the isomers containing hexa-coordinated Al atoms.

  14. Soviet Tactics for Warfare at Sea: Two Decades of Upheaval

    DTIC Science & Technology

    1982-11-01

    can deliver a strike without entering the area of action of fighters providing air cover for ships"); A.N. Sukhanov , "Vliyanie razvitiya tekhniki i... Sukhanov , A.N. "Vliyanie razvitiya tekhniki i oruzhiya na taktiku aviatsii pri deystviyakh po korablyam v more" [Impact of the development of

  15. Isotope Geochemistry of Possible Terrestrial Analogue for Martian Meteorite ALH84001

    NASA Technical Reports Server (NTRS)

    Mojzsis, Stephen J.

    2000-01-01

    We have studied the microdomain oxygen and carbon isotopic compositions by SIMS of complex carbonate rosettes from spinel therzolite xenoliths, hosted by nepheline basanite, from the island of Spitsbergen (Norway). The Quaternary volcanic rocks containing the xenoliths erupted into a high Arctic environment and through relatively thick continental crust containing carbonate rocks. We have attempted to constrain the sources of the carbonates in these rocks by combined O-18/O-16 and C-13/C-12 ratio measurements in 25 micron diameter spots of the carbonate and compare them to previous work based primarily on trace-element distributions. The origin of these carbonates can be interpreted in terms of either contamination by carbonate country rock during ascent of the xenoliths in the host basalt, or more probably by hydrothermal processes after emplacement. The isotopic composition of these carbonates from a combined delta.18O(sub SMOW) and delta.13C(sub PDB) standpoint precludes a primary origin of these minerals from the mantle. Here a description is given of the analysis procedure, standardization of the carbonates, major element compositions of the carbonates measured by electron microprobe, and their correlated C and O isotope compositions as measured by ion microprobe. Since these carbonate rosettes may represent a terrestrial analogue to the carbonate "globules" found in the martian meteorite ALH84001 interpretations for the origin of the features found in the Spitsbergen may be of interest in constraining the origin of these carbonate minerals on Mars.

  16. Aqueous Alteration of Carbonaceous Chondrites: New Insights from Comparative Studies of Two Unbrecciated CM2 Chondrites, Y 791198 and ALH 81002

    NASA Technical Reports Server (NTRS)

    Chizmadia, L. J.; Brearley, A. J.

    2004-01-01

    Carbonaceous chondrites are an important resource for understanding the physical and chemical conditions in the early solar system. In particular, a long-standing question concerns the role of water in the cosmochemical evolution of carbonaceous chondrites. It is well established that extensive hydration of primary nebular phases occurred in the CM and CI chondrites, but the location where this alteration occurred remains controversial. In the CM2 chondrites, hydration formed secondary phases such as serpentine, tochilinite, pentlandite, carbonate and PCP. There are several textural observations which suggest that alteration occurred before the accretion of the final CM parent asteroid, i.e. preaccretionary alteration. Conversely, there is a significant body of evidence that supports parent-body alteration. In order to test these two competing hypotheses further, we studied two CM chondrites, Y-791198 and ALH81002, two meteorites that exhibit widely differing degrees of aqueous alteration. In addition, both meteorites have primary accretionary textures, i.e. experienced minimal asteroidal brecciation. Brecciation significantly complicates the task of unraveling alteration histories, mixing components that have been altered to different degrees from different locations on the same asteroidal parent body. Alteration in Y-791198 is mostly confined to chondrule mesostases, FeNi metal and fine-grained matrix and rims. In comparison, the primary chondrule silicates in ALH81002 have undergone extensive replacement by secondary hydrous phases. This study focuses on compositional and textural relationships between chondrule mesostasis and the associated rim materials. Our hypothesis is: both these components are highly susceptible to aqueous alteration and should be sensitive recorders of the alteration process. For parent body alteration, we expect systematic coupled mineralogical and compositional changes in rims and altered mesostasis, as elemental exchange between these

  17. Looking for Martian True Polar Wander in mutually oriented slices of ALH84001

    NASA Astrophysics Data System (ADS)

    Buz, J.; Murphy, T. G.; Kirschvink, J. L.

    2016-12-01

    True polar wander (TPW) on Mars has been hypothesized based on a variety of observations including geoid instability [1], locations of apparent polar deposits [2], and locations of magnetic anomalies [3, 4]. A proposed driving force for TPW is redistribution of mass on the surface of the planet such as by extensive volcanism events [5]. The majority of TPW modeling research has been using orbital datasets and modeling. However, laboratory analyses of Martian samples should also be conducted to test for Martian TPW. The Martian meteorite, ALH84001, is a prime sample for observing Martian TPW because of its preservation of thermal remanent magnetization from Mars [6]. Previous work on the sample has demonstrated that the interior of the meteorite was not heated above 40 C during transport from Mars to Earth and that there is a heterogeneous magnetization within the meteorite [7]. Within the meteorite are a series of fracture-filling carbonate blebs which contain magnetite and pyrrhotite with original remanence. These carbonates are presumed to have precipitated onto the meteorite [8]. We have divided a fracture-containing portion of the meteorite into three sets of sequential, mutually oriented slices. Using an ultra-high resolution scanning SQuID magnetometer we are able to visualize the magnetization within each slice. We are able to model each magnetic scan as a series of discrete dipoles using a modification from Lima and Weiss [9]. Our results demonstrate that within one of our slice sequences the dipoles lie along a great circle path. Dipoles lying along an arc in a stereographic projection can be interpreted as resulting from TPW if there is a significant amount of time from start to end of magnetization. Our ongoing work includes continued analysis and scanning of our slices as well as statistical tests for confirming if the dipoles lie along an arc. [1] Sprenke, KF et al. 2005 Icarus 174(2) 486-9 [2] Perron, JT et al. 2007 Nature 447(7146) 840-3 [3

  18. Covariant C and O Isotope Trends in Arctic Carbonate Crusts and ALH 84001: Potential Biomarker or Indicator of Cryogenic Formation Environment?

    NASA Technical Reports Server (NTRS)

    Socki, Richard A.; Niles, Paul B.; Blake, Weston; Leveille, Richard

    2009-01-01

    This work seeks to use the chemical, isotopic, and mineralogical characteristics of secondary carbonate minerals produced during brief aqueous events to identify the conditions of the aqueous environment in which they formed. Liquid water near the surface of Mars is subject to either rapid freezing and/or evaporation. These processes are also active on Earth, and produce secondary minerals that have complex chemical, mineralogical, and isotopic textures and compositions that can include covariant relationships between Delta C-13 (sub VPDB) and delta O-18 (sub VSMOW). The extremely well studied four billion year old carbonates preserved in martian meteorite ALH 84001 also show covariant delta C-13 and delta O-18 compositions, but these variations are manifested on a micro-scale in a single thin section while the variation observed so far in terrestrial carbonates is seen between different hand samples.

  19. Calcification of the acetabular labrum of the hip: prevalence in the general population and relation to hip articular cartilage and fibrocartilage degeneration.

    PubMed

    Hawellek, Thelonius; Hubert, Jan; Hischke, Sandra; Krause, Matthias; Bertrand, Jessica; Schmidt, Burkhard C; Kronz, Andreas; Püschel, Klaus; Rüther, Wolfgang; Niemeier, Andreas

    2018-05-30

    Meniscal calcification is considered to play a relevant role in the pathogenesis of osteoarthritis of the knee. Little is known about the biology of acetabular labral disease and its importance in hip pathology. Here, we analyze for the first time the calcification of the acetabular labrum of the hip (ALH) and its relation to hip cartilage degeneration. In this cross-sectional post-mortem study of an unselected sample of the general population, 170 ALH specimens and 170 femoral heads from 85 donors (38 female, 47 male; mean age 62.1 years) were analyzed by high-resolution digital contact radiography (DCR) and histological degeneration grade. The medial menisci (MM) from the same 85 donors served as an intra-individual reference for cartilage calcification (CC). Scanning electron microscopy (SEM), energy dispersive analysis (ED) and Raman spectroscopy were performed for characterization of ALH CC. The prevalence of CC in the ALH was 100% and that in the articular cartilage of the hip (ACH) was 96.5%. Quantitative analysis revealed that the amount of ALH CC was higher than that in the ACH (factor 3.0, p < 0.001) and in the MM (factor 1.3, p < 0.001). There was significant correlation between the amount of CC in the fibrocartilage of the left and right ALH (r = 0.70, p < 0.001). Independent of age, the amount of ALH CC correlated with histological degeneration of the ALH (Krenn score) (r = 0.55; p < 0.001) and the ACH (Osteoarthritis Research Society International (OARSI), r = 0.69; p < 0.001). Calcification of the ALH was characterized as calcium pyrophosphate dihydrate deposition. The finding that ALH fibrocartilage is a strongly calcifying tissue is unexpected and novel. The fact that ALH calcification correlates with cartilage degeneration independent of age is suggestive of an important role of ALH calcification in osteoarthritis of the hip and renders it a potential target for the prevention and treatment of hip joint degeneration.

  20. Density functional theory studies on the solvent effects in Al(H2O)63+ water-exchange reactions: the number and arrangement of outer-sphere water molecules.

    PubMed

    Liu, Li; Zhang, Jing; Dong, Shaonan; Zhang, Fuping; Wang, Ye; Bi, Shuping

    2018-03-07

    Density functional theory (DFT) calculations combined with cluster models are performed at the B3LYP/6-311+G(d,p) level for investigating the solvent effects in Al(H 2 O) 6 3+ water-exchange reactions. A "One-by-one" method is proposed to obtain the most representative number and arrangement of explicit H 2 Os in the second hydration sphere. First, all the possible ways to locate one explicit H 2 O in second sphere (N m ' = 1) based on the gas phase structure (N m ' = 0) are examined, and the optimal pathway (with the lowest energy barrier) for N m ' = 1 is determined. Next, more explicit H 2 Os are added one by one until the inner-sphere is fully hydrogen bonded. Finally, the optimal pathways with N m ' = 0-7 are obtained. The structural and energetic parameters as well as the lifetimes of the transition states are compared with the results obtained with the "Independent-minimum" method and the "Independent-average" method, and all three methods show that the pathway with N m ' = 6 may be representative. Our results give a new idea for finding the representative pathway for water-exchange reactions in other hydrated metal ion systems.

  1. Experimental Shock Decomposition of Siderite to Magnetite

    NASA Technical Reports Server (NTRS)

    Bell, M. S.; Golden, D. C.; Zolensky, M. E.

    2005-01-01

    The debate about fossil life on Mars includes the origin of magnetites of specific sizes and habits in the siderite-rich portions of the carbonate spheres in ALH 84001 [1,2]. Specifically [2] were able to demonstrate that inorganic synthesis of these compositionally zoned spheres from aqueous solutions of variable ion-concentrations is possible. They further demonstrated the formation of magnetite from siderite upon heating at 550 C under a Mars-like CO2-rich atmosphere according to 3FeCO3 = Fe3O4 + 2CO2 + CO [3] and they postulated that the carbonates in ALH 84001 were heated to these temperatures by some shock event. The average shock pressure for ALH 84001, substantially based on the refractive index of diaplectic feldspar glasses [3,4,5] is some 35-40 GPa and associated temperatures are some 300-400 C [4]. However, some of the feldspar is melted [5], requiring local deviations from this average as high as 45-50 GPa. Indeed, [5] observes the carbonates in ALH 84001 to be melted locally, requiring pressures in excess of 60 GPa and temperatures > 600 C. Combining these shock studies with the above inorganic synthesis of zoned carbonates it seems possible to produce the ALH 84001 magnetites by the shock-induced decomposition of siderite.

  2. Neonatal case studies using active leptospermum honey.

    PubMed

    Mohr, Lynn D; Reyna, Roxana; Amaya, Rene

    2014-01-01

    Treatment of the neonatal patient with clinically complex wounds creates a challenge due to the safety and efficacy issues associated with the use of many advanced wound care products. The purpose of this case series was to present outcomes of 3 neonates with wounds of differing etiologies managed by Active Leptospermum Honey (ALH). Clinical case series. Clinical experiences with 3 neonates, 1 male and 2 females, are described. These premature infants received care at Rush University Medical Center, Houston, Texas, or Driscoll Children's Hospital, Corpus Christi, Texas. Each neonate presented with dissimilar wounds and differing treatment goals. For a premature infant with left foot ischemia, ALH dressings allowed for removal of nonviable tissue and facilitated the granulation of the open wounds. This removal of nonviable tissue coupled with the facilitation of granulation tissue enabled the premature infant's toe tips to be salvaged without requiring aggressive surgical intervention. For the 2 preterm infants with extravasation of intravenous solutions, ALH dressings allowed healing and increased tissue granulation without any noted toxicity to the wound bed. Further, the method of action of ALH includes an osmotic pull effect that reduced periwound erythema and edema. Although the use of ALH has been well documented in adult care, these case studies demonstrate its potential use in different wound etiologies in 3 neonatal patients.

  3. Extent of Atypical Hyperplasia Stratifies Breast Cancer Risk in Two Independent Cohorts of Women

    PubMed Central

    Degnim, Amy C.; Dupont, William D.; Radisky, Derek C.; Vierkant, Robert A.; Frank, Ryan D.; Frost, Marlene H.; Winham, Stacey J.; Sanders, Melinda E.; Smith, Jeffrey R.; Page, David L.; Hoskin, Tanya L.; Vachon, Celine M.; Ghosh, Karthik; Hieken, Tina J.; Denison, Lori A.; Carter, Jodi M.; Hartmann, Lynn C.; Visscher, Daniel W.

    2016-01-01

    Background Women with atypical hyperplasia (AH) on breast biopsy have a substantially increased risk of breast cancer (BC). Here we report BC risk with AH extent and subtype in two separate cohorts. Methods All samples containing AH were included from two cohorts of benign breast disease, Mayo Clinic and Nashville. Histology review quantified the number of foci of atypical ductal hyperplasia (ADH) and atypical lobular hyperplasia (ALH). BC risk was stratified for number of AH foci within AH subtypes. Results The study included 708 Mayo and 466 Nashville AH subjects. In the Mayo Cohort, increasing foci of AH was associated with a significant increase in risk of BC, both for ADH (RR’s of 2.61, 5.21, and 6.36 for 1, 2, and 3+ foci, p=0.006 for linear trend) and for ALH (RR’s of 2.56, 3.50, and 6.79 for 1, 2, and 3+ foci, p=0.001 for linear trend). In the Nashville Cohort, RR’s of BC for ADH were 2.70, 5.17, and 15.06 for 1, 2, and 3+ foci respectively (p<0.001 for linear trend); for ALH, RR’s also increased but not significantly (2.61, 3.48, and 4.02, p=0.148). Combining both Mayo and Nashville samples, risk increased significantly for 1, 2, and 3+ foci: RR’s of 2.65, 5.19, and 8.94 for ADH (p<0.001), and 2.58, 3.49, and 4.97 for ALH (p=0.001). Conclusions In two independent cohort studies of benign breast disease, extent of atypia stratifies long-term breast cancer risk for ADH and ALH. PMID:27352219

  4. Solid State NMR Studies of the Aluminum Hydride Phases

    NASA Technical Reports Server (NTRS)

    Hwang, Son-Jong; Bowman, R. C., Jr.; Graetz, Jason; Reilly, J. J.

    2006-01-01

    Several solid state NMR techniques including magic-angle-spinning (MAS) and multiple-quantum (MQ) MAS experiments have been used to characterize various AlH3 samples. MAS-NMR spectra for the 1H and 27Al nuclei have been obtained on a variety of AlH3 samples that include the (beta)- and (gamma)- phases as well as the most stable (alpha)-phase. While the dominant components in these NMR spectra correspond to the aluminum hydride phases, other species were found that include Al metal, molecular hydrogen (H2), as well as peaks that can be assigned to Al-O species in different configurations. The occurrence and concentration of these extraneous components are dependent upon the initial AlH3 phase composition and preparation procedures. Both the (beta)-AlH3 and (gamma)-AlH3 phases were found to generate substantial amounts of Al metal when the materials were stored at room temperature while the (alpha)-phase materials do not exhibit these changes.

  5. Breast cancer risk by extent and type of atypical hyperplasia: An update from the Nurses' Health Studies.

    PubMed

    Collins, Laura C; Aroner, Sarah A; Connolly, James L; Colditz, Graham A; Schnitt, Stuart J; Tamimi, Rulla M

    2016-02-15

    Women with atypical hyperplasia (AH) on a benign breast biopsy specimen are at increased risk for the development of breast cancer. However, the relation between the type and extent of AH (atypical ductal hyperplasia [ADH] vs atypical lobular hyperplasia [ALH]) and the magnitude of the breast cancer risk is not well defined. A nested case-control study of benign breast disease and breast cancer risk was conducted. Women with breast cancer and prior benign breast biopsy findings (488 cases) were matched to women with prior benign breast biopsy findings who were free from breast cancer (1907 controls). Benign breast biopsy slides were reviewed and categorized as nonproliferative, proliferative without atypia, or AH (ADH or ALH). The number of foci of AH was also recorded. Among women with ADH, the interrelation between the extent of atypia and breast cancer risk was not significant (odds ratio [OR] for 1 or 2 foci, 3.5; 95% confidence interval [CI], 2.2-5.6; OR for ≥3 foci, 2.7; 95% CI, 1.4-5.1; P = .41). Similarly, although the risk with ALH was higher for those with ≥3 foci than for those with <3 foci, the difference was not statistically significant (OR for 1 or 2 foci, 5.2; 95% CI, 2.7-10.0; OR for ≥3 foci, 8.0; 95% CI, 4.5-14.2; P = .19). This analysis demonstrates that the extent of ADH or ALH does not significantly contribute to breast cancer risk. The lack of a significant dose-response relation between the extent and type of atypia and breast cancer risk suggests that it would be premature to use the extent of atypia to influence management decisions for women with ADH or ALH. © 2015 American Cancer Society.

  6. Breast Cancer Risk by Extent and Type of Atypical Hyperplasia: An Update from the Nurses’ Health Studies

    PubMed Central

    Collins, Laura C.; Aroner, Sarah; Connolly, James L.; Colditz, Graham A.; Schnitt, Stuart J.; Tamimi, Rulla M.

    2015-01-01

    Background Women with atypical hyperplasia (AH) on a benign breast biopsy (BBB) are at increased risk for the development of breast cancer. However, the relationship between type and extent of AH (atypical ductal hyperplasia (ADH) vs. atypical lobular hyperplasia (ALH)) and magnitude of breast cancer risk is not well-defined. Methods We conducted a nested case-control study of benign breast disease and breast cancer risk. Women with breast cancer and a prior BBB (cases=488) were matched to women with a prior BBB but free from breast cancer (controls=1907). BBB slides were reviewed and categorized as either non-proliferative, proliferative without atypia, or AH (ADH or ALH). The number of foci of AH was also recorded. Results Among women with ADH, the inter-relationship between extent of atypia and breast cancer risk was not significant (OR=3.5; 95%CI 2.2-5.6 for 1-2 foci, OR= 2.7; 95%CI 1.4-5.1 for ≥3 foci; p=0.58). Similarly, while the risk with ALH was higher for those with ≥3 foci than for those with <3 foci, the difference was not statistically significant (OR=5.2; 95%CI 2.7-10.0 for 1-2 foci; OR=8.0; 95%CI 4.5-14.2 for ≥3 foci; p=0.66). Conclusion This analysis demonstrates that the extent of ADH or ALH did not significantly contribute to breast cancer risk. The lack of a significant dose-response relationship between extent and type of atypia and breast cancer risk suggests that it would be premature to use extent of atypia to influence management decisions in women with ADH or ALH. PMID:26565738

  7. LEW85332: A C2 Chondrite in the CR Clan

    NASA Astrophysics Data System (ADS)

    Prinz, M.; Weisberg, M. K.; Brearley, A.; Grady, M. M.; Pillinger, C.; Clayton, R. N.; Mayeda, T. K.

    1992-07-01

    Introduction. LEW85332 was described as a unique C3 chondrite [1] and we undertook this study to learn more about its relationship to other carbonaceous chondrites. We find it to be a C2 chondrite with significant similarites to CR2 chondrites. This linkage extends to the ALH85085 [2] and Acfer 182 [3,4] chondrites, although there are some important differences among them. Petrologic and isotopic similarities define the CR clan, which consists of CR chondrites and their three relatives noted above (and Bencubbin). Some differences are due to major component abundances (chondrules, matrix, metal), and some to minor differences between components, but the similarities are greater and define the clan. Results. Petrogically, LEW85332 has over 60% (vol) chondrules, about 30% matrix and matrix clasts, and about 4-7% metal. Extensive weathering makes modal abundances uncertain. Chondrules are anhydrous, about 170 micrometers wide [1] and of all textural types. ALH85085 chondrules average 20 micrometers and are mainly pyroxene-rich, whereas Acfer 182 is more like LEW85332. Matrix is hydrous and occurs as interstitial matrix, matrix clasts, and chondrule rims [5]. The matrix contains phyllosilicates and magnetite framboids. Matrix clasts are not foreign [1], but part of the chondrite, making it C2. This is also the case for Acfer 182 [3], and perhaps ALH85085. Phyllosilicates are mainly saponite and serpentine [5], and their composition is similar to that in CR chondrites. The water/rock ratio was low. Metal abundances in LEW85332 [1] are lower than in Acfer 182 (9.3 vol%) [4] and ALH85085 (22%) [6]. However, FeNi composition is the same, with a positive Ni-Co trend equivalent to the solar abundance ratio. This is the same as that in CR chondrites [7]. LEW85332 contains 0.5% carbon, combusting between 200 and 500 degrees C, indicating fine-grained, poorly crystalline carbon, or organic material. It contains 259 ppm nitrogen with delta^15N = +249o/oo. Most nitrogen is

  8. A Case of Intractable Hemophagocytic Syndrome Associated with Systemic Lupus Erythematosus Resistant to Corticosteroids and Intravenous Cyclophosphamide that Was Successfully Treated with Cyclosporine A.

    PubMed

    Toko, Hirofumi; Tsuboi, Hiroto; Umeda, Naoto; Honda, Fumika; Ohyama, Ayako; Takahashi, Hidenori; Abe, Saori; Yokosawa, Masahiro; Asashima, Hiromitsu; Hagiwara, Shinya; Hirota, Tomoya; Kondo, Yuya; Matsumoto, Isao; Sumida, Takayuki

    2018-05-18

    Hemophagocytic syndrome (HPS) associated with systemic lupus erythematosus (SLE), dubbed acute lupus hemophagocytic syndrome (ALHS), is an intractable complication of SLE. A 24-year-old man who had been diagnosed with SLE three months previously, presented with fever, rash, hallucination, and pancytopenia accompanied with hyperferritinemia and bone marrow hemophagocytosis. He was diagnosed with ALHS and neuropsychiatric (NP)-SLE. Although 4 courses of methylprednisolone pulse therapy and 1 course of intravenous cyclophosphamide (IVCY) improved his NP-SLE, his ALHS did not respond. However, the addition of cyclosporine A (CsA) led to a rapid remission from ALHS. This suggests the usefulness of CsA in the treatment of intractable, corticosteroid- and IVCY-resistant ALHS.

  9. Using Real-Time PCR to Quantify Aster Yellows Phytoplasma in its Insect Vector; Relationship of Infectivity to Transmissibility in the Aster Leafhopper

    USDA-ARS?s Scientific Manuscript database

    The aster yellows (AY) index is used to prescribe insecticide sprays that target Macrosteles quadrilineatus, or aster leafhopper (ALH), the vector of the aster yellows phytoplasma (AYp). The AY index metric is the product of the proportion of infective ALHs and the relative ALH population size at a ...

  10. Analysis of Siderite Thermal Decomposition by Differential Scanning Calorimetry

    NASA Technical Reports Server (NTRS)

    Bell, M. S.; Lin, I.-C.; McKay, D. S.

    2000-01-01

    Characterization of carbonate devolitilization has important implications for atmospheric interactions and climatic effects related to large meteorite impacts in platform sediments. On a smaller scale, meteorites contain carbonates which have witnessed shock metamorphic events and may record pressure/temperature histories of impact(s). ALH84001 meteorite contains zoned Ca-Mg-Fe-carbonates which formed on Mars. Magnetite crystals are found in the rims and cores of these carbonates and some are associated with void spaces leading to the suggestion by Brearley et al. that the crystals were produced by thermal decomposition of the carbonate at high temperature, possibly by incipient shock melting or devolitilization. Golden et al. recently synthesized spherical Mg-Fe-Ca-carbonates from solution under mild hydrothermal conditions that have similar carbonate compositional zoning to those of ALH84001. They have shown experimental evidence that the carbonate-sulfide-magnetite assemblage in ALH84001 can result from a multistep inorganic process involving heating possibly due to shock events. Experimental shock studies on calcium carbonate prove its stability to approx. 60 GPa, well in excess of the approx. 45 GPa peak pressures indicated by other shock features in ALH84001. In addition, Raman spectroscopy of carbonate globules in ALH84001 indicates no presence of CaO and MgO. Such oxide phases should be found associated with the magnetites in voids if these magnetites are high temperature shock products, the voids resulting from devolitilization of CO2 from calcium or magnesium carbonate. However, if the starting material was siderite (FeCO3), thermal breakdown of the ALH84001 carbonate at 470 C would produce iron oxide + CO2. As no documentation of shock effects in siderite exists, we have begun shock experiments to determine whether or not magnetite is produced by the decomposition of siderite within the < 45GPa pressure window and by the resultant thermal pulse to approx

  11. Allan Hills 76005 Polymict Eucrite Pairing Group: Curatorial and Scientific Update on a Jointly Curated Meteorite

    NASA Technical Reports Server (NTRS)

    Righter, K.

    2011-01-01

    Allan Hills 76005 (or 765) was collected by the joint US-Japan field search for meteorites in 1976-77. It was described in detail as "pale gray in color and consists of finely divided macrocrystalline pyroxene-rich matrix that contains abundant clastic fragments: (1) Clasts of white, plagioclase-rich rocks. (2) Medium-gray, partly devitrified, cryptocrystalline. (3) Monomineralic fragments and grains of pyroxene, plagioclases, oxide minerals, sulfides, and metal. In overall appearance it is very similar to some lunar breccias." Subsequent studies found a great diversity of basaltic clast textures and compositions, and therefore it is best classified as a polymict eucrite. Samples from the 1976-77, 77-78, and 78-79 field seasons (76, 77, and 78 prefixes) were split between US and Japan (NIPR). The US specimens are currently at NASA-JSC, Smithsonian Institution, or the Field Museum in Chicago. After this initial finding of ALH 76005, the next year s team recovered one additional mass ALH 77302, and then four additional masses were found during the third season ALH 78040 and ALH 78132, 78158 and 78165. The joint US-Japan collection effort ended after three years and the US began collecting in the Trans-Antarctic Mountains with the 1979-80 and subsequent field seasons. ALH 79017 and ALH 80102 were recovered in these first two years, and then in 1981-82 field season, 6 additional masses were recovered from the Allan Hills. Of course it took some time to establish pairing of all of these specimens, but altogether the samples comprise 4292.4 g of material. Here will be summarized the scientific findings as well as some curatorial details of how specimens have been subdivided and allocated for study. A detailed summary is also presented on the NASA-JSC curation webpage for the HED meteorite compendium.

  12. Estimation of Mesoscale Atmospheric Latent Heating Profiles from TRMM Rain Statistics Utilizing a Simple One-Dimensional Model

    NASA Technical Reports Server (NTRS)

    Iacovazzi, Robert A., Jr.; Prabhakara, C.

    2002-01-01

    In this study, a model is developed to estimate mesoscale-resolution atmospheric latent heating (ALH) profiles. It utilizes rain statistics deduced from Tropical Rainfall Measuring Mission (TRMM) data, and cloud vertical velocity profiles and regional surface thermodynamic climatologies derived from other available data sources. From several rain events observed over tropical ocean and land, ALH profiles retrieved by this model in convective rain regions reveal strong warming throughout most of the troposphere, while in stratiform rain regions they usually show slight cooling below the freezing level and significant warming above. The mesoscale-average, or total, ALH profiles reveal a dominant stratiform character, because stratiform rain areas are usually much larger than convective rain areas. Sensitivity tests of the model show that total ALH at a given tropospheric level varies by less than +/- 10 % when convective and stratiform rain rates and mesoscale fractional rain areas are perturbed individually by +/- 15 %. This is also found when the non-uniform convective vertical velocity profiles are replaced by one that is uniform. Larger variability of the total ALH profiles arises when climatological ocean- and land-surface temperatures (water vapor mixing ratios) are independently perturbed by +/- 1.0 K (+/- 5%) and +/- 5.0 K (+/- 15%), respectively. At a given tropospheric level, such perturbations can cause a +/- 25% variation of total ALH over ocean, and a factor-of-two sensitivity over land. This sensitivity is reduced substantially if perturbations of surface thermodynamic variables do not change surface relative humidity, or are not extended throughout the entire model evaporation layer. The ALH profiles retrieved in this study agree qualitatively with tropical total diabatic heating profiles deduced in earlier studies. Also, from January and July 1999 ALH-profile climatologies generated separately with TRMM Microwave Imager and Precipitation Radar rain

  13. Estimation of Mesoscale Atmospheric Latent Heating Profiles from TRMM Rain Statistics Utilizing a Simple One-Dimensional Model

    NASA Technical Reports Server (NTRS)

    Iacovazzi, Robert A., Jr.; Prabhakara, C.; Lau, William K. M. (Technical Monitor)

    2001-01-01

    In this study, a model is developed to estimate mesoscale-resolution atmospheric latent heating (ALH) profiles. It utilizes rain statistics deduced from Tropical Rainfall Measuring Mission (TRMM) data, and cloud vertical velocity profiles and regional surface thermodynamic climatologies derived from other available data sources. From several rain events observed over tropical ocean and land, ALH profiles retrieved by this model in convective rain regions reveal strong warming throughout most of the troposphere, while in stratiform rain regions they usually show slight cooling below the freezing level and significant warming above. The mesoscale-average, or total, ALH profiles reveal a dominant stratiform character, because stratiform rain areas are usually much larger than convective rain areas. Sensitivity tests of the model show that total ALH at a given tropospheric level varies by less than +/- 10 % when convective and stratiform rain rates and mesoscale fractional rain areas are perturbed individually by 1 15 %. This is also found when the non-uniform convective vertical velocity profiles are replaced by one that is uniform. Larger variability of the total ALH profiles arises when climatological ocean- and land-surface temperatures (water vapor mixing ratios) are independently perturbed by +/- 1.0 K (+/- 5 %) and +/- 5.0 K (+/- 15 %), respectively. At a given tropospheric level, such perturbations can cause a +/- 25 % variation of total ALH over ocean, and a factor-of-two sensitivity over land. This sensitivity is reduced substantially if perturbations of surface thermodynamic variables do not change surface relative humidity, or are not extended throughout the entire model evaporation layer. The ALH profiles retrieved in this study agree qualitatively with tropical total diabatic heating profiles deduced in earlier studies. Also, from January and July 1999 ALH-profile climatologies generated separately with TRMM Microwave Imager and Precipitation Radar rain

  14. ARC-1996-AC96-0345-11

    NASA Image and Video Library

    1996-10-10

    Martian Meteorite (ALH84001): This high resolution transmission electron microscope image is of a cast, or replica, from a chip of a Martian meteorite, labeled ALH84001, that shows the outline of what are believed to be possible microscopic fossils of bacteria-like organisms that may have lived on Mars more than 3.6 billion years ago. The tubular features in this image are less than a micrometer in size, or about 1/500th the diameter of a human hair. (JSC ref: S96-12637)

  15. A Pilot Study of the Efficacy of Active Leptospermum Honey for the Treatment of Partial-Thickness Facial Burns.

    PubMed

    Duncan, Christina L; Enlow, Paul T; Szabo, Margo M; Tolchin, Eric; Kelly, Robert W; Castanon, Lourdes; Aballay, Ariel M

    2016-08-01

    Research suggests that active Leptospermum honey (ALH) improves outcomes in patients with partial-thickness burns by enhancing healing and reepithelialization rates, as well as by protecting against antibiotic-resistant microorganisms. This study assessed the effectiveness of ALH gel on healing time, bacterial growth, patient satisfaction, and cost of treatment. Single-arm, prospective case series. Seven patients (aged 7-64 years) with partial-thickness facial burns were recruited from a northeastern US burn center. All patients cleansed their wounds daily with soap and water, after which they applied ALH gel. Three physicians independently rated healing using wound photography and daily tests for the presence of exudate. Wound cultures on days 1 and 7 (±2 days) assessed bacterial growth. Patients completed a satisfaction survey at the end of treatment, and cost of treatment was calculated. Healing time ranged from 3 to 14 days (mean, 8.1 days). Wound cultures revealed normal bacterial growth on days 1 and 7 for all patients. Patients rated ALH gel favorably, with the most common complaint of stickiness in 5 patients. One patient experienced transient burning on application that did not interrupt treatment. Average hospital-based cost of treatment was $26.15 per patient. Healing time was congruent with or better than what would have been expected with standard treatment. Furthermore, despite no antibiotic treatment, wound culture results yielded no abnormal bacterial growth. Finally, patients overall reported satisfaction with treatment. The findings of this study suggest that ALH is a clinically and economically valuable treatment for partial-thickness facial burns.

  16. Successful management of angiolymphoid hyperplasia with eosinophilia in a split-face trial of topical tacrolimus and timolol solution.

    PubMed

    Chacon, Anna; Mercer, Jessica

    2016-08-01

    Angiolymphoid hyperplasia with eosinophilia (ALHE) is an uncommon, benign condition characterized by multiple benign angiomatous nodules or plaques. Cutaneous lesions can be painful, pruritic, pulsatile, or potentially disfiguring resulting in significant morbidity. ALHE is a pathologic diagnosis featuring proliferations of capillary-sized vessels with epithelioid endothelial cells surrounded by larger, thick-walled vessels and accompanying eosinophils and lymphocytes. Surgery is generally required, however the skin lesions often recur after excision. ALHE is notoriously difficult to treat and many physicians would prefer a non-invasive treatment of choice. We report a case of ALHE that was successfully treated with the novel use of topical tacrolimus in a split-face trial with topical timolol solution.

  17. Understanding the premalignant potential of atypical hyperplasia through its natural history: A longitudinal cohort study

    PubMed Central

    Hartmann, Lynn C; Radisky, Derek C; Frost, Marlene H; Santen, Richard J; Vierkant, Robert A; Benetti, Lorelle L; Tarabishy, Yaman; Ghosh, Karthik; Visscher, Daniel W; Degnim, Amy C

    2014-01-01

    Atypical hyperplasia is a high risk premalignant lesion of the breast, but its biology is poorly understood. Many believe that atypical ductal hyperplasia (ADH) is a direct precursor for low-grade ductal breast cancer (BC) while atypical lobular hyperplasia (ALH) serves as a risk indicator. These assumptions underlie current clinical recommendations. We tested these assumptions by studying the characteristics of the breast cancers (BCs) that develop in women with ADH or ALH. Using the Mayo Benign Breast Disease Cohort, we identified all women with ADH or ALH from 1967–2001 and followed them for later BCs, characterizing side of BC vs side of atypia; time to BC; type, histology and grade of BC, looking for patterns consistent with precursors vs risk indicators. 698 women with atypical hyperplasia were followed a mean of 12.5 years; 143 developed BC. For both ADH and ALH, there is a 2:1 ratio of ipsilateral to contralateral BCs. The ipsilateral predominance is marked in the first five years, consistent with a precursor phenotype for both ADH and ALH. For both, there is a predominance of invasive ductal cancers with 69% of moderate or high-grade. 25% are node positive. Both ADH and ALH portend risk for DCIS and invasive BCs, predominantly ductal, with two thirds moderate or high-grade. The ipsilateral breast is at especially high risk for BC in the first five years after atypia, with risk remaining elevated in both breasts long-term. ADH and ALH behave similarly in terms of later BC endpoints. PMID:24480577

  18. Safety and efficacy of active Leptospermum honey in neonatal and paediatric wound debridement.

    PubMed

    Amaya, R

    2015-03-01

    Safety is a critically important factor in the selection of products used in neonatal and paediatric wound care. Given the lack of standardisation of neonatal and paediatric wound care protocols, the goal of this study was to present data on the safety and efficacy of active Leptospermum honey (ALH) in this patient population. A multicentre, retrospective chart review was conducted at eight inpatient facilities and one outpatient clinic between October 2011 and March 2014. The number of applications of ALH, adverse events, and the success of debridement and wound healing were recorded. Data were collected on 115 neonatal and paediatric patients, with 121 wounds requiring debridement, treated with ALH. Patients were treated for an average of 18.7 days. ALH was well tolerated, with two (1.7%) patients reporting adverse events involving a transient stinging sensation on application, which did not prohibit additional applications of ALH. Successful debridement was achieved in 86.0% (104 wounds), and 77.7% (94 wounds) were successfully closed using nonsurgical intervention. Outcomes in neonates were similar to the overall paediatric population, with 86.1% (31/36) wounds successfully debrided with no adverse events. In a subset of six patients with available pre- and post-treatment data, no clinically meaningful changes in white blood cell counts or glucose levels were associated with the initiation of treatment with ALH. The results of this study support ALH as a safe and effective treatment option in this group of patients. This study was supported by a grant from Derma Sciences (Princeton, NJ USA). Dr Amaya is a paid speaker for Derma Sciences.

  19. Differential responses of autonomic function in sea level residents, acclimatized lowlanders at >3500 m and Himalayan high altitude natives at >3500 m: A cross-sectional study.

    PubMed

    Dhar, Priyanka; Sharma, Vijay K; Das, Saroj K; Barhwal, Kalpana; Hota, Sunil K; Singh, Shashi B

    2018-04-09

    We studied the differential responses of autonomic function in sea level residents (SLR), acclimatized lowlanders (ALH) in high altitude (HA) and HA natives (HAN) at >3500 m. Out of 771 male volunteers included in this cross-sectional study, SLR, ALH and HAN groups were comprised of 351, 307 and 113 volunteers, respectively. Our results showed persistent sympathetic dominance with significantly reduced (p < 0.05) parasympathetic response in ALH as compared to SLR and HAN populations. This may be attributed to significantly increased (p < 0.05) concentration of coronary risk factors and plasma catecholamines in ALH as compared to SLR and HAN. The ALH also showed significantly increased (p < 0.05) level of serum homocysteine as compared to SLR. The HAN exhibited no changes in autonomic function despite significantly elevated (p < 0.05) homocysteine level as compared to SLR. Our findings may have clinical relevance for assessment of susceptibility to cardiovascular risks in HA dwellers, native highlanders and patients with hypoxemia. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Characterization of Spitsbergen Disks by Transmission Electron Microscopy and Raman Spectroscopy

    NASA Technical Reports Server (NTRS)

    Thomas-Keprta, K. L.; Clemett, S. J.; Le, L.; Ross, K.; McKay, David S.; Gibson, E. K., Jr.

    2010-01-01

    'Carbonate disks' found in the fractures and pores spaces of peridotite xenoliths and basalts from the island of Spitsbergen in the Norwegian Svalbard archipelago have been suggested to be "The best (and best documented) terrestrial analogs for the [Martian meteorite] ALH84001 carbonate globules ..." Previous studies have indicated that Spitsbergen carbonates show broadly comparable internal layering and mineral compositions to ALH84001 carbonate-magnetite disks. We report here for the first time, the detailed mineral characterization of Spitsbergen carbonates and their spatial relationship to the host mineral assemblages in the xenolith, using high resolution TEM (as used previously for ALH84001 carbonate disks). These studies were conducted in concert with complementary Raman and SEM analysis of the same samples. Our results indicate that there are significant chemical and physical differences between the disks in Spitsbergen and the carbonates present in ALH84001.

  1. Reconstruction of the Exposure Histories of 20 Allan Hills Ordinary Chondrites on the Basis of Cosmogenic 10Be, 26Al, Noble Gases, and Cosmic Ray Tracks

    NASA Astrophysics Data System (ADS)

    Neupert, U.; Knauer, M.; Michel, R.; Loeken, Th.; Schultz, L.; Dittrich-Hannen, B.; Suter, M.; Kubik, P. W.; Metzler, K.; Romstedt, J.

    1995-09-01

    Twenty ordinary chondrites from the 1988/89 meteorite search (ALH 88004, 88008, 88010, 88011, 88013, 88016 to 88021, 88026 to 88031, 88033, 88039, 88042) [1,2] were investigated for 10Be and 26Al, and for He, Ne and Ar by accelerator and rare gas mass spectrometry, respectively. Cosmic ray tracks were measured in samples of ALH 88019. Using theoretical production rates calculated by a physical model [3] the experimental data are interpreted with respect to the reconstruction of the preatmospheric exposure conditions and exposure histories of the meteoroids. Ordinary chondrites are particularly well suited to exemplify the capabilities of an interpretation of many cosmogenic nuclides measured in one sample. Model calculations of GCR production rates were performed for 10Be, 26Al, 3He, 21Ne, 22Ne and 38Ar as reported elsewhere [4,5]. For all meteorites, except for ALH 88019, the cosmogenic nuclide data can be explained by simple one stage exposure histories between 3 Ma and 44 Ma in meteoroids with radii between 5 cm and 85 cm. Exposure ages were derived from cosmogenic 3He, 21Ne and 38Ar on the basis of the theoretical production rates as function of3He/21Ne and 22Ne/21Ne as well as on the empirical ones proposed by Eugster [6]. The average ratios of exposure ages determined from theoretical production rates to those calculated according to Eugster [6] were 1.08+/-0.11, 1.11+/-0.25 and 1.12+/-0.17 in case of 3He, 21Ne and 38Ar, respectively. Repeated measurements of 10Be and 26Al in ALH 88019 resulted in 10.4+/-1.3 dpm/kg and 5.6+/-0.5 dpm/kg, respectively. But, the cosmogenic rare gas concentrations point to a (single stage) exposure age of 39 Ma in a meteoroid. This is in accordance with a measured cosmic ray track density in olivine of 2.8 * 10^6 cm^-2. The samples are from depths betwen 3 cm and 8 cm. Based on the track data we obtain a minimum meteoroid radius of 8 cm. The low 10Be and 26Al cannot be explained by a one stage exposure history and a long

  2. Peering Through a Martian Veil: ALHA84001 Sm-Nd Age Revisited

    NASA Technical Reports Server (NTRS)

    Nyquist, Laurence E.; Shih, Chi-Yu

    2013-01-01

    The ancient Martian orthopyroxenite ALH84001experienced a complex history of impact and aqueous alteration events. Here we summarize Sm-147-Nd-143 and Sm-146-Nd-142 analyses performed at JSC. Further, using REE data, we model the REE abundance pattern of the basaltic magma parental to ALH84001 cumulus orthopyroxene. We find the Sm-146-Nd-142 isotopic data to be consistent with isotopic evolution in material having the modeled Sm/Nd ratio from a time very close to the planet's formation to igneous crystallization of ALH84001 as inferred from the Sm-Nd studies.

  3. Magnetotactic bacteria on Earth and on Mars.

    PubMed

    McKay, Christopher P; Friedmann, E Imre; Frankel, Richard B; Bazylinski, Dennis A

    2003-01-01

    Continued interest in the possibility of evidence for life in the ALH84001 Martian meteorite has focused on the magnetite crystals. This review is structured around three related questions: is the magnetite in ALH84001 of biological or non-biological origin, or a mixture of both? does magnetite on Earth provide insight to the plausibility of biogenic magnetite on Mars? could magnetotaxis have developed on Mars? There are credible arguments for both the biological and non-biological origin of the magnetite in ALH84001, and we suggest that more studies of ALH84001, extensive laboratory simulations of non-biological magnetite formation, as well as further studies of magnetotactic bacteria on Earth will be required to further address this question. Magnetite grains produced by bacteria could provide one of the few inorganic traces of past bacterial life on Mars that could be recovered from surface soils and sediments. If there was biogenic magnetite on Mars in sufficient abundance to leave fossil remains in the volcanic rocks of ALH84001, then it is likely that better-preserved magnetite will be found in sedimentary deposits on Mars. Deposits in ancient lakebeds could contain well-preserved chains of magnetite clearly indicating a biogenic origin.

  4. Magnetotactic bacteria on Earth and on Mars

    NASA Technical Reports Server (NTRS)

    McKay, Christopher P.; Friedmann, E. Imre; Frankel, Richard B.; Bazylinski, Dennis A.

    2003-01-01

    Continued interest in the possibility of evidence for life in the ALH84001 Martian meteorite has focused on the magnetite crystals. This review is structured around three related questions: is the magnetite in ALH84001 of biological or non-biological origin, or a mixture of both? does magnetite on Earth provide insight to the plausibility of biogenic magnetite on Mars? could magnetotaxis have developed on Mars? There are credible arguments for both the biological and non-biological origin of the magnetite in ALH84001, and we suggest that more studies of ALH84001, extensive laboratory simulations of non-biological magnetite formation, as well as further studies of magnetotactic bacteria on Earth will be required to further address this question. Magnetite grains produced by bacteria could provide one of the few inorganic traces of past bacterial life on Mars that could be recovered from surface soils and sediments. If there was biogenic magnetite on Mars in sufficient abundance to leave fossil remains in the volcanic rocks of ALH84001, then it is likely that better-preserved magnetite will be found in sedimentary deposits on Mars. Deposits in ancient lakebeds could contain well-preserved chains of magnetite clearly indicating a biogenic origin.

  5. Detection and variability of Aster Yellows Phytoplasma Titer in its insect vector, Macrosteles quadrilineatus (Hemiptera: Cicadellidae)

    USDA-ARS?s Scientific Manuscript database

    The aster yellows phytoplasma (AYp) is transmitted by the aster leafhopper (ALH), Macrosteles quadrilineatus Forbes, in a persistent and propagative manner. To study AYp replication and examine the variability of AYp titer in individual ALHs, we developed a quantitative, real-time PCR (qPCR) assay t...

  6. Risk profile of breast cancer following atypical hyperplasia detected through organized screening.

    PubMed

    Buckley, Elizabeth; Sullivan, Tom; Farshid, Gelareh; Hiller, Janet; Roder, David

    2015-06-01

    Few population-based data are available indicating the breast cancer risk following detection of atypia within a breast screening program. Prospectively collected data from the South Australian screening program were linked with the state cancer registry. Absolute and relative breast cancer risk estimates were calculated for ADH and ALH separately, and by age at diagnosis and time since diagnosis. Post-hoc analysis was undertaken of the effect of family history on breast cancer risk. Women with ADH and ALH had an increase in relative risk for malignancy (ADH HR 2.81 [95% CI 1.72, 4.59] and (ALH HR 4.14 [95% CI 1.97, 8.69], respectively. Differences in risk profile according to time since diagnosis and age at diagnosis were not statistically significant. Estimates of the relative risk of breast cancer are necessary to inform decisions regarding clinical management and/or treatment of women with ADH and ALH. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Cryogenic Origin for Mars Analog Carbonates in the Bockfjord Volcanic Complex Svalbard (Norway)

    NASA Technical Reports Server (NTRS)

    Amundsen, H. E. F.; Benning, L.; Blake, D. F.; Fogel, M.; Ming, D.; Skidmore, M.; Steele, A.

    2011-01-01

    The Sverrefjell and Sigurdfjell eruptive centers in the Bockfjord Volcanic Complex (BVC) on Svalbard (Norway) formed by subglacial eruptions ca. 1 Ma ago. These eruptive centers carry ubiquitous magnesian carbonate deposits including dolomitemagnesite globules similar to those in the Martian meteorite ALH84001. Carbonates in mantle xenoliths are dominated by ALH84001 type carbonate globules that formed during quenching of CO2-rich mantle fluids. Lava hosted carbonates include ALH84001 type carbonate globules occurring throughout lava vesicles and microfractures and massive carbonate deposits associated with vertical volcanic vents. Massive carbonates include < or equal 5 cm thick magnesite deposits protruding downwards into clear blue ice within volcanic vents and carbonate cemented lava breccias associated with volcanic vents. Carbonate cements comprise layered deposits of calcite, dolomite, huntite, magnesite and aragonite associated with ALH84001 type carbonate globules lining lava vesicles. Combined Mossbauer, XRD and VNIR data show that breccia carbonate cements at Sverrefjell are analog to Comanche carbonates at Gusev crater.

  8. Angiolymphoid hyperplasia with eosinophilia-acquired port-wine-stain-like lesions: attempt at treatment with the argon laser.

    PubMed

    Pasyk, K A; Elsenety, E N; Schelbert, E B

    1988-01-01

    An unusual case of angiolymphoid hyperplasia with eosinophilia (ALHE) simulating port-wine stain in a 50-year-old woman is reported. The lesions of ALHE are typically papules or subcutaneous masses that range from light pink to red-brown in color. In addition to the usual histologic findings of ALHE, the biopsy in our patient showed some fibrin-like material and fibrous long-spacing collagen on ultrastructural examination. This unusual lesion necessitates biopsy because the differential diagnosis includes port-wine stain, sarcoidosis, lupus erythematosus, and non-Hodgkin lymphoma (mycosis fungoides). Many different forms of treatment have been attempted for ALHE including radiotherapy, cytotoxic chemotherapy, corticosteroids, and antibiotics. The lesions in our patient responded to argon laser therapy and surgical excision, though there has been recurrence on the border of the treated area. Because laser energy is noncumulative in the tissues and effective in removing the lesions, we recommend it as the treatment of choice for these lesions.

  9. Magnetic resonance imaging-guided core needle breast biopsies resulting in high-risk histopathologic findings: upstage frequency and lesion characteristics.

    PubMed

    Weinfurtner, R Jared; Patel, Bhavika; Laronga, Christine; Lee, Marie C; Falcon, Shannon L; Mooney, Blaise P; Yue, Binglin; Drukteinis, Jennifer S

    2015-06-01

    Analysis of magnetic resonance imaging-guided breast biopsies yielding high-risk histopathologic features at a single institution found an overall upstage rate to malignancy of 14% at surgical excision. All upstaged lesions were associated with atypical ductal hyperplasia. Flat epithelial atypia and atypical lobular hyperplasia alone or with lobular carcinoma in situ were not associated with an upstage to malignancy. The purpose of the present study w as to determine the malignancy upstage rates and imaging features of high-risk histopathologic findings resulting from magnetic resonance imaging (MRI)-guided core needle breast biopsies. These features include atypical ductal hyperplasia (ADH), atypical lobular hyperplasia (ALH), flat epithelial atypia (FEA), and lobular carcinoma in situ (LCIS). A retrospective medical record review was performed on all MRI-guided core needle breast biopsies at a single institution from June 1, 2007 to December 1, 2013 to select biopsies yielding high-risk histopathologic findings. The patient demographics, MRI lesion characteristics, and histopathologic features at biopsy and surgical excision were analyzed. A total of 257 MRI-guided biopsies had been performed, and 50 yielded high-risk histopathologic features (19%). Biopsy site and surgical excision site correlation was confirmed in 29 of 50 cases. Four of 29 lesions (14%) were upstaged: 1 case to invasive ductal carcinoma and 3 cases to ductal carcinoma in situ. ADH alone had an overall upstage rate of 7% (1 of 14), mixed ADH/ALH a rate of 75% (3 of 4), ALH alone or with LCIS a rate of 0% (0 of 7), and FEA a rate of 0% (0 of 4). Only mixed ADH/ALH had a statistically significant upstage rate to malignancy compared with the other high-risk histopathologic subtypes combined. No specific imaging characteristics on MRI were associated with an upstage to malignancy on the statistical analysis. MRI-guided breast biopsies yielding high-risk histopathologic features were associated with

  10. Analysis of the bonding in XH3Cu+ (XB, Al, Ga) complexes

    NASA Astrophysics Data System (ADS)

    Corral, Inés; Mó, Otilia; Yáñez, Manuel

    High-level density functional theory (DFT) calculations on XH3Cu+ (XB, Al, Ga) complexes show that the attachment of the metal cation to the base takes place through agostic-type interactions. These interactions that can be viewed as dative bonds from the σXH bonding orbitals of the base toward low-lying empty 4s orbitals of the metal cation, and back-donations from the lone pairs of the metal into the σ *XH antibonding orbitals of the neutral, are particularly favored when the XH bonds have a high X+δH-δ polarity. Accordingly, the AlH3 and GaH3 Cu+ binding energies are very similar, but much larger than that of BH3. Depopulation of the σXH bonding orbital and the concomitant population of the σ *XH antibonding orbital involved in the agostic interaction result in a significant weakening of the corresponding XH linkages, whose bond length increases and whose stretching frequency appears red-shifted.

  11. The History of Allan Hills 84001 Revised: Multiple Shock Events

    NASA Technical Reports Server (NTRS)

    Treiman, Allan H.

    1998-01-01

    The geologic history of Martian meteorite Allan Hills (ALH) 84001 is more complex than previously recognized, with evidence for four or five crater-forming impacts onto Mars. This history of repeated deformation and shock metamorphism appears to weaken some arguments that have been offered for and against the hypothesis of ancient Martian life in ALH 84001. Allan Hills 84001 formed originally from basaltic magma. Its first impact event (I1) is inferred from the deformation (D1) that produced the granular-textured bands ("crush zones") that transect the original igneous fabric. Deformation D1 is characterized by intense shear and may represent excavation or rebound flow of rock beneath a large impact crater. An intense thermal metamorphism followed D1 and may be related to it. The next impact (I2) produced fractures, (Fr2) in which carbonate "pancakes" were deposited and produced feldspathic glass from some of the igneous feldspars and silica. After I2, carbonate pancakes and globules were deposited in Fr2 fractures and replaced feldspathic glass and possibly crystalline silicates. Next, feldspars, feldspathic glass, and possibly some carbonates were mobilized and melted in the third impact (I3). Microfaulting, intense fracturing, and shear are also associated with 13. In the fourth impact (I4), the rock was fractured and deformed without significant heating, which permitted remnant magnetization directions to vary across fracture surfaces. Finally, ALH 84001 was ejected from Mars in event I5, which could be identical to I4. This history of multiple impacts is consistent with the photogeology of the Martian highlands and may help resolve some apparent contradictions among recent results on ALH 84001. For example, the submicron rounded magnetite grains in the carbonate globules could be contemporaneous with carbonate deposition, whereas the elongate magnetite grains, epitaxial on carbonates, could be ascribed to vapor-phase deposition during I3.

  12. House Dust Endotoxin and Peripheral Leukocyte Counts: Results from Two Large Epidemiologic Studies.

    PubMed

    Fessler, Michael B; Carnes, Megan U; Salo, Päivi M; Wilkerson, Jesse; Cohn, Richard D; King, Debra; Hoppin, Jane A; Sandler, Dale P; Travlos, Greg; London, Stephanie; Thorne, Peter; Zeldin, Darryl

    2017-05-31

    The peripheral leukocyte count is a biomarker of inflammation and is associated with human all-cause mortality. Although causes of acute leukocytosis are well-described, chronic environmental determinants of leukocyte number are less well understood. We investigated the relationship between house dust endotoxin concentration and peripheral leukocyte counts in human subjects. The endotoxin–leukocyte relationship was evaluated by linear regression in the National Health and Nutrition Examination Survey (NHANES) 2005–2006 (n=6,254) and the Agricultural Lung Health Study (ALHS; n=1,708). In the ALHS, we tested for a gene [Toll-like Receptor 4 ( TLR4 ), encoding the endotoxin receptor]-by-environment interaction in the endotoxin–leukocyte relationship using regression models with an interaction term. There is a statistically significant, positive association between endotoxin concentration and total leukocyte number [estimated change, 0.186×10 3 /μL (95% CI: 0.070, 0.301×10 3 /μL) per 10-fold change in endotoxin; p=0.004) in the NHANES. Similar positive associations were found for monocytes, lymphocytes, and neutrophils. Stratified analyses revealed possible effect modification by asthma and chronic obstructive pulmonary disease. We observed similar associations in the ALHS. For total leukocytes, there was suggestive evidence in the ALHS of a gene-by-environment interaction for minor allele carrier status at the TLR4 haplotype defined by rs4986790 and rs4986791 (interaction p=0.15). This is, to our knowledge, the first report of an association between house dust endotoxin and leukocyte count in a national survey. The finding was replicated in a farming population. Peripheral leukocyte count may be influenced by residential endotoxin exposure in diverse settings. https://doi.org/10.1289/EHP661.

  13. Evidence for shock heating and constraints on Martian surface temperatures revealed by 40Ar/ 39Ar thermochronometry of Martian meteorites

    NASA Astrophysics Data System (ADS)

    Cassata, William S.; Shuster, David L.; Renne, Paul R.; Weiss, Benjamin P.

    2010-12-01

    The thermal histories of Martian meteorite are important for the interpretation of petrologic, geochemical, geochronological, and paleomagnetic constraints that they provide on the evolution of Mars. In this paper, we quantify 40Ar/ 39Ar ages and Ar diffusion kinetics of Martian meteorites Allan Hills (ALH) 84001, Nakhla, and Miller Range (MIL) 03346. We constrain the thermal history of each meteorite and discuss the resulting implications for their petrology, paleomagnetism, and geochronology. Maskelynite in ALH 84001 yields a 40Ar/ 39Ar isochron age of 4163 ± 35 Ma, which is indistinguishable from recent Pb-Pb ( Bouvier et al., 2009a) and Lu-Hf ages ( Lapen et al., 2010). The high precision of this result arises from clear resolution of a reproducible trapped 40Ar/ 36Ar component in maskelynite in ALH 84001 ( 40Ar/ 36Ar = 632 ± 90). The maskelynite 40Ar/ 39Ar age predates the Late Heavy Bombardment and likely represents the time at which the original natural remanent magnetization (NRM) component observed in ALH 84001 was acquired. Nakhla and MIL 03346 yield 40Ar/ 39Ar isochron ages of 1332 ± 24 and 1339 ± 8 Ma, respectively, which we interpret to date crystallization. Multi-phase, multi-domain diffusion models constrained by the observed Ar diffusion kinetics and 40Ar/ 39Ar age spectra suggest that localized regions within both ALH 84001 and Nakhla were intensely heated for brief durations during shock events at 1158 ± 110 and 913 ± 9 Ma, respectively. These ages may date the marginal melting of pyroxene in each rock, mobilization of carbonates and maskelynite in ALH 84001, and NRM overprints observed in ALH 84001. The inferred peak temperatures of the shock heating events (>1400 °C) are sufficient to mobilize Ar, Sr, and Pb in constituent minerals, which may explain some of the dispersion observed in 40Ar/ 39Ar, Rb-Sr, and U-Th-Pb data toward ages younger than ˜4.1 Ga. The data also place conservative upper bounds on the long-duration residence

  14. Building "Applied Linguistic Historiography": Rationale, Scope, and Methods

    ERIC Educational Resources Information Center

    Smith, Richard

    2016-01-01

    In this article I argue for the establishment of "Applied Linguistic Historiography" (ALH), that is, a new domain of enquiry within applied linguistics involving a rigorous, scholarly, and self-reflexive approach to historical research. Considering issues of rationale, scope, and methods in turn, I provide reasons why ALH is needed and…

  15. Histology after lumpectomy in women with epithelial atypia on stereotactic vacuum-assisted breast biopsy.

    PubMed

    Graesslin, O; Antoine, M; Chopier, J; Seror, J Y; Flahault, A; Callard, P; Daraï, E; Uzan, S

    2010-02-01

    Large-core needle biopsy of the breast (LCNB) and vacuum-assisted breast biopsy (VABB) are widely used as alternatives to open surgical biopsy (OSB) for initial diagnosis of mammographic abnormalities. Between 18% and 80% of cases in which such specimens show atypical lobular hyperplasia (ALH) or atypical ductal hyperplasia (ADH) are found to be malignant at surgery. From 1999 to 2005, 68 women with mammographic abnormalities were sampled by stereotactic VABB and presented atypical epithelial hyperplasia. Immunohistochemical staining with anti-cytokeratin 5/6 and anti-E-cadherin antibodies was performed. All women underwent a lumpectomy. Clinical, radiological or histological factors predictive of the risk of finding malignancy at surgery were sought. VABB initially showed 28 cases of ADH, 32 cases of ALH, one case of flat epithelial atypia, five cases of mixed atypia, and two cases of Lobular Carcinoma In Situ (LCIS). After slide review with immunohistochemical staining, two cases of ADH were reclassified as simple hyperplasia and two cases of ALH were reclassified as mixed atypia. Seven lesions (10.3%) that appeared to be benign on VABB were found to be malignant on OSB (Ductal Carcinoma In Situ (DCIS) in six cases and invasive ductal carcinoma in one case). ADH was the only predictive factor of malignancy on OSB (p=0.04 versus ALH). ADH diagnosed by vacuum-assisted breast biopsy frequently corresponds to cancer on open surgical biopsy. Surgical excision of all breast lesions containing atypical hyperplasia on percutaneous biopsy can be recommended. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  16. Mineralization of Bacteria in Terrestrial Basaltic Rocks: Comparison With Possible Biogenic Features in Martian Meteorite Allan Hills 84001

    NASA Technical Reports Server (NTRS)

    Thomas-Keprta, K. L.; McKay, D. S.; Wentworth, S. J.; Stevens, T. O.; Taunton, A. E.; Allen, C. C.; Gibson, E. K., Jr.; Romanek, C. S.

    1998-01-01

    The identification of biogenic features altered by diagenesis or mineralization is important in determining whether specific features in terrestrial rocks and in meteorites may have a biogenic origin. Unfortunately, few studies have addressed the formation of biogenic features in igneous rocks, which may be important to these phenomena, including the controversy over possible biogenic features in basaltic martian meteorite ALH84001. To explore the presence of biogenic features in igneous rocks, we examined microcosms growing in basaltic small-scale experimental growth chambers or microcosms. Microbial communities were harvested from aquifers of the Columbia River Basalt (CRB) group and grown in a microcosm containing unweathered basalt chips and groundwater (technique described in. These microcosms simulated natural growth conditions in the deep subsurface of the CRB, which should be a good terrestrial analog for any putative martian subsurface ecosystem that may have once included ALH84001. Here we present new size measurements and photomicrographs comparing the putative martian fossils to biogenic material in the CRB microcosms. The range of size and shapes of the biogenic features on the CRB microcosm chips overlaps with and is similar to those on ALH84001 chips. Although this present work does not provide evidence for the biogenicity of ALH84001 features, we believe that, based on criteria of size, shape, and general morphology, a biogenic interpretation for the ALH84001 features remains plausible.

  17. Orthopyroxenes as Recorders of Diogenite Petrogenesis: Al-Cr-Ti Systematics

    NASA Astrophysics Data System (ADS)

    Fowler, G. W.; Papike, J. J.; Spilde, M. N.; Shearer, C. K.

    1993-07-01

    This research represents a continuing effort to understand the petrogenesis of diogenites and their relationship to eucrites. Our present suite of 17 diogenites includes: Aioun El Atrouss, Ellemeet, Garland, Ibbenburen, Johnstown, Manegoan, Peckelsheim, Roda, Shalka, Tatahouine, EET 83246, EET 83247, EET 87530, EET A79002, LEW 88008, and olivine diogenites ALH 84001 and ALH A77256. In our previous studies [1,2], we reported major, minor, and trace element systematics for a subgroup of 13 of these samples. In these studies, we concluded that Fe/Mg was compromised by post-crystallization annealing reactions. We also demonstrated [1] strong, positive correlations between Cr and Al along several trajectories on a Cr-Al data display. REE and Zr-Ti systematics indicate that most sampled diogenites represent cumulates from similar basaltic melts. These modeled melt compositions are similar to eucrites but show a greater compositional range. Here we further explore the Al-Cr-Ti systematics. Figure 1 (figures include over 1,000 high quality EMP analyses) is a Ti-Al plot that shows a main trend with a positive correlation between Ti and Al. Rhoda and one of the assemblages in polymict Garland have elevated Ti concentrations relative to the main trend while Manegoan has relatively depleted Ti concentrations. Figure 2 is a (Cr+Ti) vs. Al plot with a main trend that shows a strong, positive correlation between (Cr+Ti) and Al. Manegoan occupies the high (Cr+Ti)-Al end of the trend while Peckelsheim occupies the low end. Olivine diogenite ALH A77256 falls distinctly off the trend. However, ALH 84001, our only other olivine diogenite, plots with the other diogenite in the main trend. Several things are indicated by these systematics. The positive correlation of (Cr+Ti) vs. Al indicate that the most important charge balance couples are ^VITi^4+-^IVAl(sub)2, ^VITi^3+-^IVAl, ^VICr^3+-^IVAl, and ^VIAl-^IVAl. The ^VIAl-^IVAl couple is relatively more important in olivine diogenite ALH

  18. Reaction paths of alane dissociation on the Si(0 0 1) surface

    NASA Astrophysics Data System (ADS)

    Smith, Richard; Bowler, David R.

    2018-03-01

    Building on our earlier study, we examine the kinetic barriers to decomposition of alane, AlH3, on the Si(0 0 1) surface, using the nudged elastic band approach within density functional theory. We find that the initial decomposition to AlH with two H atoms on the surface proceeds without a significant barrier. There are several pathways available to lose the final hydrogen, though these present barriers of up to 1 eV. Incorporation is more challenging, with the initial structures less stable in several cases than the starting structures, just as was found for phosphorus. We identify a stable route for Al incorporation following selective surface hydrogen desorption (e.g. by scanning tunneling microscope tip). The overall process parallels PH3, and indicates that atomically precise acceptor doping should be possible.

  19. Hydrogen release reactions of Al-based complex hydrides enhanced by vibrational dynamics and valences of metal cations

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

    Sato, T.; Ramirez-Cuesta, Anibal J.; Daemen, Luke L.

    2016-08-31

    Hydrogen release from Al-based complex hydrides composed of metal cation(s) and [AlH4] – was investigated using inelastic neutron scattering viewed from vibrational dynamics. Here, the hydrogen release followed the softening of translational and [AlH4] – librational modes, which was enhanced by vibrational dynamics and the valence(s) of the metal cation(s).

  20. Successful Capture, Extraction and Identification of Hypervelocity CM2 Meteorite Fragments Shot by Light-Gas Gun

    NASA Technical Reports Server (NTRS)

    Snead, C.; Westphal, A. J.; Dominguez, G.; Zolensky, M. E.

    2003-01-01

    Here we report the successful capture, extraction and identification of two fragments of a CM2 meteorite (ALH83100) into lowdensity aerogel. The shot was carried out at the AVGR at NASAARC. A mixture of powdered ALH83100 and borosilicate glass microspheres was shot at 4.55.0 km/sec into 50 mg cm silicate aerogel.

  1. A Thermal Infrared Emission Spectra Library for Unpowdered Meteorites

    NASA Astrophysics Data System (ADS)

    Ashley, J. W.; Christensen, P. R.

    2007-12-01

    Mid-infrared thermal emission spectra have been obtained for whole-rock (unpowdered) samples of the following 25 meteorites: Abee, Admire, Allende, Bondoc, Brahin, Bruderheim, Canyon Diablo, Carichic, Clover Springs, Dhofar 007, Estherville, Holbrook, Juancheng, Kapoeta, Long Island, Marion, Modoc, ALH77225, ALH77233, ALH84082, LEW85322, ALH85025, ALH79029, ALH77004, and LEW86015. Meteorites were provided through the Center for Meteorite Studies at ASU, Johnson Space Center and the NASA Antarctic Meteorite Working Group, and from private collections. The database was prepared to aid in the on-going detection and interpretation of meteorites on Mars using the Miniature Thermal Emission Spectrometer (Mini-TES) instruments on both Mars Exploration Rovers. It therefore includes several specimens of low, moderate, and high weathering intensities, reflecting different levels of water exposure in desert and non-desert environments. Unweathered falls are also considered. Samples represent all three chondrite classes, stony irons (mesosiderites and pallasites), and select achondrites. Special consideration is given to dust-covered iron-nickel meteorites as part of a separate study designed to evaluate the Mini-TES spectra of iron-nickel meteorites on Mars. All samples were analyzed at or near a temperature of 80° C using a modified Nicolet Nexus 670 FT-IR spectrometer at the Mars Space Flight Facility at Arizona State University. Data were collected within the 2000 to 200 wavenumber (5 to 50 microns) mid-infrared range. The results show that many meteorite types display moderate to wide variability in the depth and position of prominent absorption features, making them easily distinguishable from each other. Most previous meteorite spectroscopy studies have either focused on near-infrared reflectance spectra [e.g. 1], and/or involved powdered samples to represent asteroid regoliths in the mid-infrared [e.g. 2 & 3]. Particle size- related issues are often at the heart of

  2. FOSB immunoreactivity in endothelia of epithelioid hemangioma (angiolymphoid hyperplasia with eosinophilia).

    PubMed

    Ortins-Pina, Ana; Llamas-Velasco, Mar; Turpin, Sara; Soares-de-Almeida, Luís; Filipe, Paulo; Kutzner, Heinz

    2018-06-01

    Accurate distinction of epithelioid hemangioma (EH) from its malignant mimics is paramount but remains challenging due to its wide morphological spectrum and lack of objective molecular markers. FOSB oncogenic activation was recently identified as a key event in endothelial proliferation. We sought to investigate the FOSB staining pattern in EH with angiolymphoid hyperplasia with eosinophilia (EH-AHLE) morphology and to evaluate its value in differential diagnosis of epithelioid vascular tumors. From the authors' files, 15 representative cases of EH-ALHE were selected and evaluated for their FOSB immunostaining pattern. Other vascular proliferations which can be morphological mimics were also tested: epithelioid hemangioendothelioma (EHE) (5 cases) and epithelioid angiosarcoma (EAS) (5 cases). All 15 cases of EH-ALHE showed strong and homogeneous FOSB nuclear expression in endothelial cells with ample cytoplasm and intracytoplasmic vacuoles. All cases of EHE and EAS lacked FOSB immunoreactivity or showed only incidental weak FOSB immunoreactivity in less than 5 nuclei per lesion. FOSB immunohistochemistry is sensitive in the diagnosis of EH-ALHE, and allows differentiation from its histological mimics. An immunohistochemical panel including not only pan-cytokeratin AE1/AE3 and endothelial markers, but also FOSB, helps in the diagnosis of epithelioid vascular tumors. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. KH+Ti co-doped NaAlH4 for high-capacity hydrogen storage

    NASA Astrophysics Data System (ADS)

    Wang, Ping; Kang, Xiang-Dong; Cheng, Hui-Ming

    2005-10-01

    A method for preparation of Ti-doped NaAlH4 with high hydrogen capacity was developed, in which the NaH/Al mixture was mechanically milled with a catalytic amount of KH together with metallic Ti. The addition of KH was found to result in a pronounced improvement in the dehydriding performance of the Na3AlH6/NaH+Al step. As a result, the practical cycling hydrogen capacity has been markedly enhanced from 3.3 wt % for the Ti-doped hydride to 4.7 wt % for KH+Ti co-doped material. Moreover, the pronounced enhancement on hydrogen capacity arising upon adding KH was observed to persist in the following dehydrogenation/hydrogenation cycles. Structural investigation shows that the addition of KH has led to a lattice expansion. Moreover, it was found that the enthalpy change of the Na3AlH6/NaH+Al decomposition step underwent a considerable decrease upon adding KH. Therefore, the observed property improvement may be ascribed to a favorable thermodynamic adjustment arising upon the addition of KH.

  4. Computational study of pristine and titanium-doped sodium alanates for hydrogen storage applications

    NASA Astrophysics Data System (ADS)

    Dathar, Gopi Krishna Phani

    formalism as implemented in CASTEP (Cambridge Serial Total Energy Package) is used to study the structure and energetics of pristine and Ti-doped sodium alanates. From investigations of various models of sodium alanates with Ti dopants, it is shown that the difference between the energy required for Ti→SNa (Ti-substituted Na at the lattice site on the surface) and Ti→TI (Ti placed on top of the surface interstitial SI site) is 0.003 eV atom-1, and is minimal compared to other models. Since less energy is required for Ti→S Na and Ti→TI, these two sites (SNa and T I) would be preferred by the Ti dopants. In Ti→SNa model, Ti is coordinated to two aluminum and seven hydrogen atoms resulting in the possible formation of a TiAl2H7 complex. At elevated temperatures (423 and 448 K), the number of aluminum atoms coordinating with titanium in the complex increase from two (at distances in the 2.6-2.7 A range) to five (at distances in the 2.6-2.7 A range). Besides the formation of a Ti-Al-H complex, Al-Al association (with a 2.97 A bond length) is also seen from the DFT-MD results. In the case of Ti→TI, Ti is coordinated to two aluminum and two hydrogen atoms resulting in the possible formation of a TiAl2H2 complex. TiAl2 H2 complex becomes TiAl3H6 and TiAl 3H7 at elevated temperatures of 423 and 448 K, respectively. The investigation of thermodynamics pathways in Ti-doped sodium alanates illustrates a three step reaction pathway to the formation of TiAl3 (Ti and AlH3 after the first reaction, TiAl after the second and finally TiAl3). This investigation also suggests aluminum in its +3 oxidation state present in aluminum hydride species is responsible in the formation of Ti-Al alloys. From kinetics studies, the proposed mechanism is related to transition from AlH4- to AlH6 3-. The rate limiting step is determined to be associated with hydrogen evolution from association of AlH3 species nucleating aluminum phase. This step is 15 kJ/mol higher than the nearest highest

  5. Effects of acute feed restriction combined with targeted use of increasing luteinizing hormone content of follicle-stimulating hormone preparations on ovarian superstimulation, fertilization, and embryo quality in lactating dairy cows

    PubMed Central

    Bender, R. W.; Hackbart, K. S.; Dresch, A. R.; Carvalho, P. D.; Vieira, L. M.; Crump, P. M.; Guenther, J. N.; Fricke, P. M.; Shaver, R. D.; Combs, D. K.; Wiltbank, M. C.

    2018-01-01

    Multiple metabolic and hormonal factors can affect the success of protocols for ovarian superstimulation. In this study, the effect of acute feed restriction and increased LH content in the superstimulatory FSH preparation on numbers of ovulations, fertilization, and embryo quality in lactating dairy cows was evaluated. Two experiments were performed using a Latin square design with treatments arranged as a 2 × 2 factorial: feed restriction (FR; 25% reduction in dry matter intake) compared with ad libitum (AL) feeding, combined with high (H) versus low (L) LH in the last 4 injections of the superstimulatory protocol. As expected, FR decreased circulating insulin concentrations (26.7 vs. 46.0 μU/mL). Two analyses were performed: one that evaluated the complete Latin square in experiment 2 and a second that evaluated only the first periods of experiments 1 and 2. For both analyses, follicle numbers, ovulation rates, and corpora lutea on d 7 were not different. In the first period analysis of experiments 1 and 2, we observed an interaction between feed allowance and amount of LH on fertilization rates, percentage of embryos or oocytes that were quality 1 and 2 embryos, and number of embryos or oocytes that were degenerate. Fertilization rates were greater for the AL-L (89.4%) and FR-H (80.1%) treatments compared with the AL-H (47.9%) and FR-L (59.9%) treatments. Similarly, the proportion of total embryos or oocytes designated as quality 1 and 2 embryos was greater for AL-L (76.7%) and FR-H (73.4%) treatments compared with AL-H (35.6%) and FR-L (47.3%) treatments. In addition, the number of degenerate embryos was decreased for AL-L (1.3) and FR-H (0.4) treatments compared with the AL-H (2.6) and FR-L (2.3) treatments. Thus, cows with either too low (FR-L) or too high (AL-H) insulin and LH stimulation had lesser embryo production after superstimulation because of reduced fertilization rate and increased percentage of degenerate embryos. Therefore, interaction of the

  6. Mineral Biomarkers in Martian Meteorite Allan Hills 84001?

    NASA Technical Reports Server (NTRS)

    Thomas-Keprta, K. L.; Bazylinski, D. A.; Wentworth, S. J.; McKay, D. S.; Golden, D. C.; Gibson, E. K., Jr.; Romanek, C. S.

    1998-01-01

    The occurrence of fine-grained magnetite in the Fe-rich rims surrounding carbonate globules in the martian meteorite ALH84001, originally described in , have been proposed as fossil remains of primitive martian organisms. Here we report observations on size and shape distributions of magnetites from ALH84001 and compare them to biogenic and inorganic magnetite crystals of terrestrial origin. While some magnetite morphology is not unequivocally diagnostic for its biogenicity, such as cubodial forms of magnetite, which are common in inorganically formed magnetites, other morphologies of magnetite (parallel-epiped or elongated prismatic and arrowhead forms) are more likely signatures of biogenic activity. Some ALH 84001 magnetite particles described below have unique morphology and length-to-width ratios that are indistinguishable from a variety of terrestrial biogenic magnetite and distinct from all known inorganic forms of magnetite.

  7. Mechanism of sodium and chloride transport in the thin ascending limb of Henle.

    PubMed Central

    Imai, M; Kokko, J P

    1976-01-01

    Our previous in vitro studies have disclosed that the thin ascending limb of Henle (tALH) possesses some unique membrane characteristics. In those studies we failed to demonstrated active transport of sodium chloride by the tALH, although it was shown that the isotopic permeability to sodium and chloride was unusually high. However, we did not examine the mechanisms by which the apparent high permeation of sodium chloride occurs. Thus the purpose of the present studies was to elucidate the mechanism of sodium chloride transport across the isolated tALH of the rabbit by conducting four different types of studies: (1) comparison of the observed chloride and sodium flux ratios to those predicted by Ussing's equation under imposed salt concentration gradients; (2) kinetic evaluation of chloride and sodium fluxes; (3) examination of the effect of bromide on the kinetics of chloride transport; and (4) experiments to test for the existence of exchange diffusion of chloride. In the first set of studies the predicted and the theoretical flux ratios of sodium were identical in those experiments in which sodium chloride was added either to the perfusate or to the bath. However, the observed chloride flux ratio, lumen-to-bath/bath-to-lumen, was significantly lower than that predicted from Ussing's equation when 100 mM sodium chloride was added to the bath. In the second set of experiments the apparent isotopic permeability for sodium and for chloride was measured under varying perfusate and bath NaCl concentrations. There was no statistical change in the apparent sodium permeability coefficient when the NaCl concentration was raised by varying increments from 85.5 to 309.5 mM. However, permeation of 36Cl decrease significantly with an increase in Cl from 73.6 to 598.6 mM. These events could be explained by a two component chloride transport process consisting of simple diffusion and a saturable facilitated diffusion process with a Vmax = 3.71 neq mm-1 min-1. In the third set

  8. High-Throughput Serum 25-Hydroxy Vitamin D Testing with Automated Sample Preparation.

    PubMed

    Stone, Judy

    2016-01-01

    Serum from bar-coded tubes, and then internal standard, are pipetted to 96-well plates with an 8-channel automated liquid handler (ALH). The first precipitation reagent (methanol:ZnSO4) is added and mixed with the 8-channel ALH. A second protein precipitating agent, 1 % formic acid in acetonitrile, is added and mixed with a 96-channel ALH. After a 4-min delay for larger precipitates to settle to the bottom of the plate, the upper 36 % of the precipitate/supernatant mix is transferred with the 96-channel ALH to a Sigma Hybrid SPE(®) plate and vacuumed through for removal of phospholipids and precipitated proteins. The filtrate is collected in a second 96-well plate (collection plate) which is foil-sealed, placed in the autosampler (ALS), and injected into a multiplexed LC-MS/MS system running AB Sciex Cliquid(®) and MPX(®) software. Two Shimadzu LC stacks, with multiplex timing controlled by MPX(®) software, inject alternately to one AB Sciex API-5000 MS/MS using positive atmospheric pressure chemical ionization (APCI) and a 1.87 min water/acetonitrile LC gradient with a 2.1 × 20 mm, 2.7 μm, C18 fused core particle column (Sigma Ascentis Express). LC-MS/MS through put is ~44 samples/h/LC-MS/MS system with dual-LC channel multiplexing. Plate maps are transferred electronically from the ALH and reformatted into LC-MS/MS sample table format using the Data Innovations LLC (DI) Instrument Manager middleware application. Before collection plates are loaded into the ALS, the plate bar code is manually scanned to download the sample table from the DI middleware to the LC-MS/MS. After acquisition-LC-MS/MS data is analyzed with AB Sciex Multiquant(®) software using customized queries, and then results are transferred electronically via a DI interface to the LIS. 2500 samples/day can be extracted by two analysts using four ALHs in 4-6 h. LC-MS/MS analysis of those samples on three dual-channel LC multiplexed LC-MS/MS systems requires 19-21 h and data analysis can be

  9. Post-metamorphic brecciation in type 3 ordinary chondrites

    NASA Technical Reports Server (NTRS)

    Scott, E. R. D.; Mccoy, T. J.; Keil, K.

    1993-01-01

    Type 3.1-3.9 ordinary chondrites can be divided into two kinds: those in which the compositions of chondrule silicates are entirely consistent with metamorphism of type 3.0 material, and those in which the computational heterogeneity appears to be too extreme for in situ metamorphism. We present petrologic data for three LL3 chondrites of the second kind--Ngawi, ALH A77278 (both type 3.6), and Hamlet (type 3.9)--and compare these data with results for the first kind of LL3-4 chondrites. Given that chondrules form in the nebula and that metamorphic equilibration occurs in asteroids, our new data imply that Ngawi, A77278, Hamlet, and many other type 3 ordinary chondrites are post-metamorphic breccias containing materials with diverse metamorphic histories; they are not metamorphic rocks or special kinds of 'primitive breccias.' We infer also that metamorphism to type 3.1-3.9 levels produces very friable material that is easily remixed into breccias and lithified by mild shock. Thus, petrologic types and subtypes of chondrites indicate the mean metamorphic history of the ingredients, not the thermal history of the rock. The metamorphic history of individual type 1 or 2 porphyritic chondrules in type 3 breccias is best derived from olivine and pyroxene analyses and the data of McCoy et al. for unbrecciated chondrites. The new chondrule classification schemes of Sears, DeHart et al., appears to provide less information about the original state and metamorphic history of individual porphyritic chondrules and should not replace existing classification schemes.

  10. Post-metamorphic brecciation in type 3 ordinary chondrites

    NASA Astrophysics Data System (ADS)

    Scott, E. R. D.; McCoy, T. J.; Keil, K.

    1993-03-01

    Type 3.1-3.9 ordinary chondrites can be divided into two kinds: those in which the compositions of chondrule silicates are entirely consistent with metamorphism of type 3.0 material, and those in which the computational heterogeneity appears to be too extreme for in situ metamorphism. We present petrologic data for three LL3 chondrites of the second kind--Ngawi, ALH A77278 (both type 3.6), and Hamlet (type 3.9)--and compare these data with results for the first kind of LL3-4 chondrites. Given that chondrules form in the nebula and that metamorphic equilibration occurs in asteroids, our new data imply that Ngawi, A77278, Hamlet, and many other type 3 ordinary chondrites are post-metamorphic breccias containing materials with diverse metamorphic histories; they are not metamorphic rocks or special kinds of 'primitive breccias.' We infer also that metamorphism to type 3.1-3.9 levels produces very friable material that is easily remixed into breccias and lithified by mild shock. Thus, petrologic types and subtypes of chondrites indicate the mean metamorphic history of the ingredients, not the thermal history of the rock. The metamorphic history of individual type 1 or 2 porphyritic chondrules in type 3 breccias is best derived from olivine and pyroxene analyses and the data of McCoy et al. for unbrecciated chondrites. The new chondrule classification schemes of Sears, DeHart et al., appears to provide less information about the original state and metamorphic history of individual porphyritic chondrules and should not replace existing classification schemes.

  11. Angiolymphoid hyperplasia with eosinophilia: a clinicopathologic study of 9 cases.

    PubMed

    Guinovart, R M; Bassas-Vila, J; Morell, L; Ferrándiz, C

    2014-03-01

    Angiolymphoid hyperplasia with eosinophilia (ALHE) is a rare disease characterized by single or multiple angiomatous lesions typically located on the scalp and the face. We present a retrospective analysis of 9 cases of ALHE. The lesions appeared largely as multiple grouped papules or, in some cases, subcutaneous nodules, located mainly on the scalp, particularly around the ear. We also observed lesions in atypical locations, such as areas of the head other than the scalp, and the shoulder, neck, and forearm. At these sites the lesions had an atypical clinical appearance that made diagnosis difficult; this should be borne in mind in patients with single, well-delimited lesions with a vascular appearance and superficial ulceration or crusting. Surgery was the most common treatment in our series, and even though ALHE is considered a benign condition, recurrence was common. Copyright © 2012 Elsevier España, S.L. and AEDV. All rights reserved.

  12. Extinct Life on Mars: Looking for Traces of Viruses Instead of Bacteria

    NASA Astrophysics Data System (ADS)

    Ksanfomality, Leonid

    The finds in the ALH 84001 meteorite were reported as a sign of traces and fossils of ancient Martian primitive life. Despite many experiments, the issue has not been settled. A study of geochemical data suggests that simple inorganic processes sometimes offer a more plausible explanation of the suspicious structures found in the ALH 84001 meteorite that had been discussed by many authors. A photo of certain micro structures got in the paper of N. Yushkin (Fig. 1) proves the point. (Figure: The inorganic structures in granites.) It is known that viruses possess an ability to survive under very severe external conditions. The Martian biogenic activity (if any) could leave its virus' sign. Thus it could make a sense to look for viruses or even DNA traces both in the body of the ALH 84001 meteorite and on Mars in future space missions instead of traces of the extinct bacteria.

  13. Materials Data on Na3AlH6 (SG:14) by Materials Project

    DOE Data Explorer

    Kristin Persson

    2014-11-02

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  14. [Construction and Characterization of B850-Only LH2 Energy Transfer System in Purple Bacteria].

    PubMed

    Li, Kai; Zhao, Chun-gui; Yue, Hui-ying; Yang, Su-ping; Qu, Yin-bo; Jiao, Nian-zhi

    2015-04-01

    To seek microscopic molecular mechanism of energy transfer and complex reconstitution in the photosynthesis, the conditions for construction of B850-only peripheral light-harvesting complex (LH2) and their properties were investigated using absorption, fluorescence spectroscopy, molecular sieve chromatography, ultrafiltration and sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) from the purple bacteria. The results indicated that bacteriochlorophylls (BChl) of B800 incubated in 10 mmo · L(-1) Tris-HCl (pH 8.0) buffer are selectively released from their binding sites of LH2 of Rhodobacter azotoformans (A-LH2) by 0.08% (W/V) SDS. B850-only A-LH2 was constructed after removing free BChl mixing with 10% methyl alcohol by ultrafiltration. B850 BChl was released after A-LH2 was incubated for 240 min in dark at room temperature (RT). While BChl of B800 incubated in pH 1.9 buffer were selectively released from their binding sites of LH2 of Rhodopseudomonas palustris (P-LH2). The authors acquired two components using molecular sieve chromatography. Free BChl of one component was not removed and self-assembled to P-LH2. The other removed free BChl and B850-only P-LH2 was constructed. B850 unchanged after P-LH2 was incubated. P-LH2 α and β subunits have different molecular weights, but those of A-LH2 are in the contrary. It is concluded that B850-only P-LH2 is more stable than A-LH2. The enigmatic split of the B800 absorption band was not observed in these LH2, but we acquired two kinds of B800-released LH2 from Rhodopseudomonas palustris. The authors' results may provide a new light to separate homogeneous Apoprotein LH2.

  15. Physiological differences between female limited, alternative life history strategies: The Alba phenotype in the butterfly Colias croceus.

    PubMed

    Woronik, Alyssa; Stefanescu, Constanti; Käkelä, Reijo; Wheat, Christopher W; Lehmann, Philipp

    Across a wide range of taxa, individuals within populations exhibit alternative life history strategies (ALHS) where their phenotypes dramatically differ due to divergent investments in growth, reproduction and survivorship, with the resulting trade-offs directly impacting Darwinian fitness. Though the maintenance of ALHS within populations is fairly well understood, little is known regarding the physiological mechanisms that underlie ALHS and how environmental conditions can affect the evolution and expression of these phenotypes. One such ALHS, known as Alba, exists within females of many species in the butterfly genus Colias. Previous works in New World species not only found that female morphs differ in their wing color due to a reallocation of resources away from the synthesis of wing pigments to other areas of development, but also that temperature played an important role in these trade-offs. Here we build on previous work conducted in New World species by measuring life history traits and conducting lipidomics on individuals reared at hot and cold temperatures in the Old World species Colias croceus. Results suggest that the fitness of Alba and orange morphs likely varies with rearing temperature, where Alba females have higher fitness in cold conditions and orange in warm. Additionally shared traits between Old and New World species suggest the Alba mechanism is likely conserved across the genus. Finally, in the cold treatment we observe an intermediate yellow morph that may have decreased fitness due to slower larval development. This cost may manifest as disruptive selection in the field, thereby favoring the maintenance of the two discrete morphs. Taken together these results add insights into the evolution of, and the selection on, the Alba ALHS. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Atypia on breast core needle biopsies: reproducibility and significance.

    PubMed

    Darvishian, Farbod; Singh, Baljit; Simsir, Aylin; Ye, Weimin; Cangiarella, Joan F

    2009-01-01

    This study analyzes the interobserver variability in interpreting atypia on breast core needle biopsies and in each category of atypia calculates the upgrade risk of carcinoma in the subsequent surgical excision. We identified 51 cases of atypia on breast core needle biopsies performed at our institution from January 2003 to August 2006. The atypia was classified into 4 categories: atypical ductal hyperplasia (ADH), atypical lobular hyperplasia (ALH), flat epithelial atypia (FEA), and atypia of undetermined significance (AUS). After a tutorial session, these cases were independently reviewed by four pathologists, whose overall multi-rater kappa value for agreement on different categories of atypia was 0.79 (95% CI, 0.69-0.89), which is within the substantial agreement range. The upgrade risk in each category of atypia was as follows: ADH 20% (p = 0.04); ALH 10% (p = 0.6); FEA 16.6% (p = 0.23), and AUS 100% (p = 0.96). Based on our findings, we conclude that follow-up excision should be performed after a diagnosis of ADH. The upgrade risk did not reach statistical significance in ALH or FEA. Although follow-up excision cannot be strongly recommended in ALH and FEA, it should be considered since the upgrade risk is not negligible. Strict adherence to the diagnostic criteria and tutorial sessions can help pathologists to achieve substantial agreement in interpreting atypia on breast core needle biopsies.

  17. Analyses at High Spatial Resolution of Organic Molecules in Extraterrestrial Samples: Two-Step Laser Mass Spectrometry: Search for Polycyclic Aromatic Hydrocarbons in Antarctic Meteorite and Micrometeorite Samples

    NASA Technical Reports Server (NTRS)

    Zare, Richard N.

    1998-01-01

    Perhaps the best way to summarize the past three-year grant period is to cite the publications and present a brief synopsis of each: 1. "Indigenous Polycyclic Aromatic Hydrocarbon Molecules in Circumstellar Graphite Grains." Bulk C-12/C-13 isotope ratios observed in some graphite grains extracted from primitive meteorites point strongly to a circumstellar origin. By applying our technique of microprobe two-step laser desorption laser ionization mass spectrometry ((mu)L(sup 2)MS) to individual circumstellar graphite grains we have measured the C-12/C-13 isotope ratio of various polycyclic aromatic hydrocarbons (PAHS) found in these grains. 2. "Deuterium Enrichments in Cluster IDPS," Large enrichments in the D/H isotope ratios in IDPs likely arise from the preservation of presolar molecules. 3. "Evidence for thermalization of surface-disorder molecules at heating rates of 10(exp 8) K/s". A careful study of the ((mu)L(sup 2)MS) of aniline-d(sub 7) from a single-crystal surface (0001) of sapphire (al2O3) shows that all measured properties are consistent with a thermal mechanism for desorption. 4. "Search for past life on Mars; possible relic biogenic activity in Martian meteorite ALH 84001. The authors examined the Martian meteorite ALH 84001 and found several lines of evidence compatible with existence of past primitive (single-cell) life on early Mars. 5. "Microprobe two-step laser mass spectrometry as an analytical tool for meteorite samples". THis paper presents a comprehensive review of (mu)L(sup 2)MS and how this technique can be applied to meteoritic samples. 6. "Indigenous polycyclic aromatic hydrocarbons in circumstellar graphite grains from primitive meteorites". The C-12/C-13 isotope ratios were measured for PAHs in a total of 89 spherical graphite grains. 7. "Observation of indigenous polycyclic aromatic hydrocarbons in "Giant" carbonaceous antarctic micrometeorites." The (mu)L(sup 2)MS method was used to establish the nature and distribution of PAHs in

  18. A benign synthesis of alane by the composition-controlled mechanochemical reaction of sodium hydride and aluminum chloride

    DOE PAGES

    Hlova, Ihor; Goldston, Jennifer F.; Gupta, Shalabh; ...

    2017-05-30

    Solid-state mechanochemical synthesis of alane (AlH 3) starting from sodium hydride (NaH) and aluminum chloride (AlCl 3) has been achieved at room temperature. The transformation pathway of this solid-state reaction was controlled by a stepwise addition of AlCl 3 to the initial reaction mixture that contained sodium hydride in excess of stoichiometric amount. As in the case of previously investigated LiH–AlCl 3 system, complete selectivity was achieved whereby formation of unwanted elemental aluminum was fully suppressed, and AlH 3 was obtained in quantitative yield. Reaction progress during each step was investigated by means of solid-state NMR and powder X-ray diffraction,more » which revealed that the overall reaction proceeds through a series of intermediate alanates that may be partially chlorinated. The NaH–AlCl 3 system presents some subtle differences compared to LiH–AlCl 3 system particularly with respect to optimal concentrations needed during one of the reaction stages. Based on the results, we postulate that high local concentrations of NaH may stabilize chlorine-containing derivatives and prevent decomposition into elemental aluminum with hydrogen evolution. As a result, complete conversion with quantitative yield of alane was confirmed by both SSNMR and hydrogen desorption analysis.« less

  19. A benign synthesis of alane by the composition-controlled mechanochemical reaction of sodium hydride and aluminum chloride

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

    Hlova, Ihor; Goldston, Jennifer F.; Gupta, Shalabh

    Solid-state mechanochemical synthesis of alane (AlH 3) starting from sodium hydride (NaH) and aluminum chloride (AlCl 3) has been achieved at room temperature. The transformation pathway of this solid-state reaction was controlled by a stepwise addition of AlCl 3 to the initial reaction mixture that contained sodium hydride in excess of stoichiometric amount. As in the case of previously investigated LiH–AlCl 3 system, complete selectivity was achieved whereby formation of unwanted elemental aluminum was fully suppressed, and AlH 3 was obtained in quantitative yield. Reaction progress during each step was investigated by means of solid-state NMR and powder X-ray diffraction,more » which revealed that the overall reaction proceeds through a series of intermediate alanates that may be partially chlorinated. The NaH–AlCl 3 system presents some subtle differences compared to LiH–AlCl 3 system particularly with respect to optimal concentrations needed during one of the reaction stages. Based on the results, we postulate that high local concentrations of NaH may stabilize chlorine-containing derivatives and prevent decomposition into elemental aluminum with hydrogen evolution. As a result, complete conversion with quantitative yield of alane was confirmed by both SSNMR and hydrogen desorption analysis.« less

  20. Passive remote sensing of altitude and optical depth of dust plumes using the oxygen A and B bands: First results from EPIC/DSCOVR at Lagrange-1 point

    NASA Astrophysics Data System (ADS)

    Xu, Xiaoguang; Wang, Jun; Wang, Yi; Zeng, Jing; Torres, Omar; Yang, Yuekui; Marshak, Alexander; Reid, Jeffrey; Miller, Steve

    2017-07-01

    We presented an algorithm for inferring aerosol layer height (ALH) and optical depth (AOD) over ocean surface from radiances in oxygen A and B bands measured by the Earth Polychromatic Imaging Camera (EPIC) on the Deep Space Climate Observatory (DSCOVR) orbiting at Lagrangian-1 point. The algorithm was applied to EPIC imagery of a 2 day dust outbreak over the North Atlantic Ocean. Retrieved ALHs and AODs were evaluated against counterparts observed by Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), Moderate Resolution Imaging Spectroradiometer, and Aerosol Robotic Network. The comparisons showed 71.5% of EPIC-retrieved ALHs were within ±0.5 km of those determined from CALIOP and 74.4% of EPIC AOD retrievals fell within a ± (0.1 + 10%) envelope of MODIS retrievals. This study demonstrates the potential of EPIC measurements for retrieving global aerosol height multiple times daily, which are essential for evaluating aerosol profile simulated in climate models and for better estimating aerosol radiative effects.

  1. Sublimation: A Mechanism for the Enrichment of Organics in Antarctic Ice

    NASA Technical Reports Server (NTRS)

    Becker, Luann; McDonald, Gene D.; Glavin, Daniel P.; Bada, Jeffrey L.; Bunch, Theodore E.; Chang, Sherwood (Technical Monitor)

    1997-01-01

    Recent analyses of the carbonate globules present in the Martian meteorite ALH84001 have detected polycyclic aromatic hydrocarbons (PAHs) at the ppm level. The distribution of PAHs observed in ALH84001 was interpreted as being inconsistent with a terrestrial origin and were claimed to be indigenous to the meteorite, perhaps derived from an ancient Martian biota. However, Becker et al., have examined PAHs in the Martian meteorite EETA79001, in several Antarctic carbonaceous chondrites and Antarctic Allan Hills Ice and detected many of the same PAHs found in ALH84001. The reported presence of L-amino acids of apparent terrestrial origin in the EETA79001 druse material, suggests that this meteorite is contaminated with terrestrial/extraterrestrial organics probably derived from Antarctic ice meltwater that had percolated through the meteorite. The detection of PAHs and L-amino acids in these Martian meteorites suggests that despite storage in the Antarctic ice, selective changes of certain chemical and mineralogical phases has occurred.

  2. Combined pulsed dye and CO2 lasers in the treatment of angiolymphoid hyperplasia with eosinophilia.

    PubMed

    Sagi, Lior; Halachmi, Shlomit; Levi, Assi; Amitai, Dan Ben; Enk, Claes D; Lapidoth, Moshe

    2016-08-01

    Angiolymphoid hyperplasia with eosinophilia (ALHE) is an uncommon dermatosis of unknown etiology that manifests as characteristic red nodules and papules with a predilection for the scalp and periauricular region. Treatment is required for both esthetic and functional reasons, as lesions may ulcerate and bleed. Many treatment approaches have been reported, including excision, systemic medical approaches, topical or intralesional therapies, and non-invasive modalities including cryotherapy, electrosurgery, and laser. Treatments have exhibited variable efficacy, and the recurrence rate is 100 %. We report the combination of pulsed dye laser and CO2 laser in the treatment of ALHE in 14 patients. All patients exhibited clinical response after a mean of 2.4 ± 0.4 treatment sessions. The clinical efficacy of the combined treatment, together with its well-tolerated nature, render the use of pulsed dye laser in combination with CO2 laser, a viable treatment for debulking ALHE lesions. Ongoing maintenance treatments are needed to due to the high degree of relapse.

  3. Amino Acids in the Antarctic Martian Meteorite MIL03346

    NASA Technical Reports Server (NTRS)

    Glavin, D. P.; Aubrey, A.; Dworkin, J. P.; Botta, O.; Bada, J. L.

    2005-01-01

    The report by McKay et al. that the Martian meteorite ALH84001 contains evidence for life on Mars remains controversial. Of central importance is whether ALH84001 and other Antarctic Martian meteorites contain endogenous organic compounds. In any investigation of organic compounds possibly derived from Mars it is important to focus on compounds that play an essential role in biochemistry as we know it and that have properties such as chirality which can be used to distinguish between biotic versus abiotic origins. Amino acids are one of the few compounds that fulfill these requirements. Previous analyses of the Antarctic Martian meteorites ALH84001 and EETA79001 have shown that these meteorites contain low levels of terrestrial amino acid contamination derived from Antarctic ice meltwater. Here we report preliminary amino acid investigations of a third Antarctic Martian meteorite MIL03346 which was discovered in Antarctica during the 2003-04 ANSMET season. Additional information is included in the original extended abstract

  4. Towards direct synthesis of alane: A predicted defect-mediated pathway confirmed experimentally

    DOE PAGES

    Wang, Lin -Lin; Herwadkar, Aditi; Reich, Jason M.; ...

    2016-08-18

    Here, alane (AlH 3) is a unique energetic material that has not found a broad practical use for over 70 years because it is difficult to synthesize directly from its elements. Using density functional theory, we examine the defect-mediated formation of alane monomers on Al(111) in a two-step process: (1) dissociative adsorption of H 2 and (2) alane formation, which are both endothermic on a clean surface. Only with Ti dopant to facilitate H 2 dissociation and vacancies to provide Al adatoms, both processes become exothermic. In agreement, in situ scanning tunneling microscopy showed that during H 2 exposure, alanemore » monomers and clusters form primarily in the vicinity of Al vacancies and Ti atoms. Moreover, ball milling of the Al samples with Ti (providing necessary defects) showed a 10 % conversion of Al into AlH 3 or closely related species at 344 bar H 2, indicating that the predicted pathway may lead to the direct synthesis of alane from elements at pressures much lower than the 104 bar expected from bulk thermodynamics.« less

  5. Isospecific propylene polymerization with in situ generated bis(phenoxy-amine)zirconium and hafnium single site catalysts.

    PubMed

    Makio, Haruyuki; Prasad, Aitha Vishwa; Terao, Hiroshi; Saito, Junji; Fujita, Terunori

    2013-07-07

    Bis(phenoxy-imine) Zr and Hf complexes were activated with (i)Bu3Al or (i)Bu2AlH in conjunction with Ph3CB(C6F5)4 and tested as catalysts for propylene polymerization with emphasis on the enantioselectivity of the isospecific species and the single site polymerization characteristics. The isoselective species was identified as the in situ generated bis(phenoxy-amine) complex whose isoselectivity was sensitive to subtle changes in ligand structure. By employing specific substituents at certain key positions the isotacticity reached an extremely high level comparable to high-end commercial isotactic polypropylenes (Tm > 160 °C). Single site polymerization characteristics depended upon the efficiency and selectivity of the in situ imine reduction which is sensitive to the substituent on the imine nitrogen and the reaction conditions. By using (i)Bu2AlH as a reducing agent, quantitative imine reduction can be achieved with a stoichiometric amount of the reducing agent. This lower alkylaluminum loading is beneficial for the catalyst and significantly enhances the polymerization activity and the molecular weight of the resultant polymer.

  6. Morphometric and kinematic sperm subpopulations in split ejaculates of normozoospermic men

    PubMed Central

    Santolaria, Pilar; Soler, Carles; Recreo, Pilar; Carretero, Teresa; Bono, Araceli; Berné, José M; Yániz, Jesús L

    2016-01-01

    This study was designed to analyze the sperm kinematic and morphometric subpopulations in the different fractions of the ejaculate in normozoospermic men. Ejaculates from eight normozoospermic men were collected by masturbation in three fractions after 3–5 days of sexual abstinence. Analyses of sperm motility by computer-assisted sperm analysis (CASA-Mot), and of sperm morphometry by computer-assisted sperm morphometry analysis (CASA-Morph) using fluorescence were performed. Clustering and discriminant procedures were performed to identify sperm subpopulations in the kinematic and morphometric data obtained. Clustering procedures resulted in the classification of spermatozoa into three kinematic subpopulations (slow with low ALH [35.6% of all motile spermatozoa], with circular trajectories [32.0%], and rapid with high ALH [32.4%]), and three morphometric subpopulations (large-round [33.9% of all spermatozoa], elongated [32.0%], and small [34.10%]). The distribution of kinematic sperm subpopulations was different among ejaculate fractions (P < 0.001), with higher percentages of spermatozoa exhibiting slow movements with low ALH in the second and third portions, and with a more homogeneous distribution of kinematic sperm subpopulations in the first portion. The distribution of morphometric sperm subpopulations was also different among ejaculate fractions (P < 0.001), with more elongated spermatozoa in the first, and of small spermatozoa in the third, portion. It is concluded that important variations in the distribution of kinematic and morphometric sperm subpopulations exist between ejaculate fractions, with possible functional implications. PMID:27624985

  7. Isotopic Composition of Trapped and Cosmogenic Noble Gases in Several Martian Meteorites

    NASA Technical Reports Server (NTRS)

    Garrison, Daniel H.; Bogard, Donald D.

    1997-01-01

    Isotopic abundances of the noble gases were measured in the following Martian meteorites: two shock glass inclusions from EET79001, shock vein glass from Shergotty and Y793605, and whole rock samples of ALH84001 and QUE94201. These glass samples, when combined with literature data on a separate single glass inclusion from EET79001 and a glass vein from Zagami, permit examination of the isotopic composition of Ne, Ar, Kr, and Xe trapped from the Martian atmosphere in greater detail. The isotopic composition of Martian Ne, if actually present in these glasses, remains poorly defined. The Ar-40/Ar-36 ratio of Martian atmospheric Ar may be much less than the ratio measured by Viking and possibly as low as approx. 1900. The atmospheric Ar-36/Ar-38 ratio is less than or equal to 4.0. Martian atmospheric Kr appears to be enriched in lighter isotopes by approx. 0.4%/amu compared to both solar wind Kr and to the Martian composition previously reported. The Martian atmospheric Ar-36/Xe-132 and Kr-84/Xe-132 Xe elemental ratios are higher than those reported by Viking by factors of approx. 3.3 and approx. 2.5, respectively. Cosmogenic gases indicate space exposure ages of 13.9 +/- 1 Myr for ALH84001 and 2.7 +/- 0.6 Myr for QUE94201. Small amounts of Ne-21 produced by energetic solar protons may be present in QUE94201, but are not present in ALH84001 or Y793605. The space exposure age for Y793605 is 4.9 +/- 0.6 Myr and appears to be distinctly older than the ages for basaltic shergottites.

  8. The role of chemoprevention in modifying the risk of breast cancer in women with atypical breast lesions.

    PubMed

    Coopey, Suzanne B; Mazzola, Emanuele; Buckley, Julliette M; Sharko, John; Belli, Ahmet K; Kim, Elizabeth M H; Polubriaginof, Fernanda; Parmigiani, Giovanni; Garber, Judy E; Smith, Barbara L; Gadd, Michele A; Specht, Michelle C; Guidi, Anthony J; Roche, Constance A; Hughes, Kevin S

    2012-12-01

    Women with atypical ductal hyperplasia (ADH), atypical lobular hyperplasia (ALH), lobular carcinoma in situ (LCIS), and severe ADH are at increased risk of breast cancer, but a systematic quantification of this risk and the efficacy of chemoprevention in the clinical setting is still lacking. The objective of this study is to evaluate a woman's risk of breast cancer based on atypia type and to determine the effect of chemoprevention in decreasing this risk. Review of 76,333 breast pathology reports from three institutions within Partners Healthcare System, Boston, from 1987 to 2010 using natural language processing was carried out. This approach identified 2,938 women diagnosed with atypical breast lesions. The main outcome of this study is breast cancer occurrence. Of the 2,938 patients with atypical breast lesions, 1,658 were documented to have received no chemoprevention, and 184/1,658 (11.1 %) developed breast cancer at a mean follow-up of 68 months. Estimated 10-year cancer risks were 17.3 % with ADH, 20.7 % with ALH, 23.7 % with LCIS, and 26.0 % with severe ADH. In a subset of patients treated from 1999 on (the chemoprevention era), those who received no chemoprevention had an estimated 10-year breast cancer risk of 21.3 %, whereas those treated with chemoprevention had a 10-year risk of 7.5 % (p < 0.001). Chemoprevention use significantly reduced breast cancer risk for all atypia types (p < 0.05). The risk of breast cancer with atypical breast lesions is substantial. Physicians should counsel patients with ADH, ALH, LCIS, and severe ADH about the benefit of chemoprevention in decreasing their breast cancer risk.

  9. Developments in the Aerosol Layer Height Retrieval Algorithm for the Copernicus Sentinel-4/UVN Instrument

    NASA Astrophysics Data System (ADS)

    Nanda, Swadhin; Sanders, Abram; Veefkind, Pepijn

    2016-04-01

    The Sentinel-4 mission is a part of the European Commission's Copernicus programme, the goal of which is to provide geo-information to manage environmental assets, and to observe, understand and mitigate the effects of the changing climate. The Sentinel-4/UVN instrument design is motivated by the need to monitor trace gas concentrations and aerosols in the atmosphere from a geostationary orbit. The on-board instrument is a high resolution UV-VIS-NIR (UVN) spectrometer system that provides hourly radiance measurements over Europe and northern Africa with a spatial sampling of 8 km. The main application area of Sentinel-4/UVN is air quality. One of the data products that is being developed for Sentinel-4/UVN is the Aerosol Layer Height (ALH). The goal is to determine the height of aerosol plumes with a resolution of better than 0.5 - 1 km. The ALH product thus targets aerosol layers in the free troposphere, such as desert dust, volcanic ash and biomass during plumes. KNMI is assigned with the development of the Aerosol Layer Height (ALH) algorithm. Its heritage is the ALH algorithm developed by Sanders and De Haan (ATBD, 2016) for the TROPOMI instrument on board the Sentinel-5 Precursor mission that is to be launched in June or July 2016 (tentative date). The retrieval algorithm designed so far for the aerosol height product is based on the absorption characteristics of the oxygen-A band (759-770 nm). The algorithm has heritage to the ALH algorithm developed for TROPOMI on the Sentinel 5 precursor satellite. New aspects for Sentinel-4/UVN include the higher resolution (0.116 nm compared to 0.4 for TROPOMI) and hourly observation from the geostationary orbit. The algorithm uses optimal estimation to obtain a spectral fit of the reflectance across absorption band, while assuming a single uniform layer with fixed width to represent the aerosol vertical distribution. The state vector includes amongst other elements the height of this layer and its aerosol optical

  10. Workshop on the Issue Martian Meteorites: Where do we Stand and Where are we Going?

    NASA Technical Reports Server (NTRS)

    1998-01-01

    The presentations in this workshop discuss the composition of Martian meteorites. Many of the talks were on a specific meteorite, i.e., Allan Hills 84001 (ALH84001). The discovery earlier of carbonates in ALH84001 lead some researchers to suggest that there was evidence of martian life. Other possible explanations for this phenomena are given. Other papers discuss methods to sterilize martian samples, the existence of water on Mars, the facilities of the Meteorite Processing Laboratory at Johnson Space Center, comparative analyses of geologic processes and the gathering of meteorites.

  11. [Benign proliferative breast disease with and without atypia].

    PubMed

    Coutant, C; Canlorbe, G; Bendifallah, S; Beltjens, F

    2015-12-01

    In the last few years, diagnostics of high-risk breast lesions (atypical ductal hyperplasia [ADH], flat epithelial atypia [FEA], lobular neoplasia: atypical lobular hyperplasia [ALH], lobular carcinoma in situ [LCIS], radial scar [RS], usual ductal hyperplasia [UDH], adenosis, sclerosing adenosis [SA], papillary breast lesions, mucocele-like lesion [MLL]) have increased with the growing number of breast percutaneous biopsies. The management of these lesions is highly conditioned by the enlarged risk of breast cancer combined with either an increased probability of finding cancer after surgery, either a possible malignant transformation (in situ or invasive cancer), or an increased probability of developing cancer on the long range. An overview of the literature reports grade C recommendations concerning the management and follow-up of these lesions: in case of ADH, FEA, ALH, LCIS, RS, MLL with atypia, diagnosed on percutaneous biopsies: surgical excision is recommended; in case of a diagnostic based on vacuum-assisted core biopsy with complete disappearance of radiological signal for FEA or RS without atypia: surgical abstention is a valid alternative approved by multidisciplinary meeting. In case of ALH (incidental finding) associated with benign lesion responsible of radiological signal: abstention may be proposed; in case of UDH, adenosis, MLL without atypia, diagnosed on percutaneous biopsies: the concordance of radiology and histopathology findings must be ensured. No data is available to recommend surgery; in case of non-in sano resection for ADH, FEA, ALH, LCIS (except pleomorphic type), RS, MLL: surgery does not seem to be necessary; in case of previous ADH, ALH, LCIS: a specific follow-up is recommended in accordance with HAS's recommendations. In case of FEA and RS or MLL combined with atypia, little data are yet available to differ the management from others lesions with atypia; in case of UDH, usual sclerosing adenosis, RS without atypia, fibro cystic

  12. Aluminum Hydride as a Fuel Supplement to NanoThermites

    DTIC Science & Technology

    2014-01-01

    nanocomposite thermite based on CuO, Bi2O3, and Fe2O3. Pressure cell and burn tube experiments demonstrated enhancements in absolute pressure...pressurization rate, and burning velocity when micron-scale aluminum hydride was used as a minor fuel component in a nanoaluminum–copper-oxide thermite ...alane, AlH3) replaced nanoaluminum incrementally as a fuel in a nanocomposite thermite based on CuO, Bi2O3, and Fe2O3. Pressure cell and burn tube

  13. Computer-Assisted Sperm Analysis (CASA) parameters and their evolution during preparation as predictors of pregnancy in intrauterine insemination with frozen-thawed donor semen cycles.

    PubMed

    Fréour, Thomas; Jean, Miguel; Mirallié, Sophie; Dubourdieu, Sophie; Barrière, Paul

    2010-04-01

    To study the potential of CASA parameters in frozen-thawed donor semen before and after preparation on silica gradient as predictors of pregnancy in IUI with donor semen cycles. CASA parameters were measured in thawed donor semen before and after preparation on a silica gradient in 132 couples undergoing 168 IUI cycles with donor semen. The evolution of these parameters throughout this process was calculated. The relationship with cycle outcome was then studied. Clinical pregnancy rate was 18.4% per cycle. CASA parameters on donor semen before or after preparation were not significantly different between pregnancy and failure groups. However, amplitude of lateral head displacement (ALH) of spermatozoa improved in all cycles where pregnancy occurred, thus predicting pregnancy with a sensitivity of 100% and a specificity of 20%. Even if CASA parameters do not seem to predict pregnancy in IUI with donor semen cycles, their evolution during the preparation process should be evaluated, especially for ALH. However, the link between ALH improvement during preparation process and pregnancy remains to be explored. Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.

  14. Flat epithelial atypia on core needle biopsy, must we surgically excise?

    PubMed

    Acott, A A; Mancino, A T

    2016-12-01

    Breast flat epithelial atypia (FEA) often coexists with more aggressive pathology and excision is currently recommended when diagnosed by core needle biopsy (CNB). Recent studies suggest isolated FEA has a low association with carcinoma and may warrant close surveillance. A radiology database containing 2189 breast CNB was reviewed for isolated FEA or FEA in combination with atypical pathology. 79 patients had FEA. There were 48/79 with isolated FEA and 31/79 concomitant FEA with ADH, ALH, or LCIS. 46 subsequent excisional biopsies of isolated FEA resulted: benign 38/46, ADH 5/46, LCIS 2/46, DCIS 1/46. Concomitant FEA + ADH/ALH/LCIS group resulted: benign 26/31, DCIS 3/31, DCIS and LCIS 1/31, tubular carcinoma 1/31. DCIS/invasive cancer on excision in the FEA + ADH group is 5/31 versus 1/46 for isolated FEA (p 0.0489). Findings support literature suggesting isolated FEA has a low association with carcinoma. These patients may not require surgical excision, but instead have close surveillance. Based on the higher cancer incidence in FEA combined with ADH, ALH, LCIS, or residual microcalcifications, we still recommend surgical excision. Breast flat epithelial atypia (FEA) often coexists with more aggressive pathology and surgical excision is currently recommended when diagnosed by core needle biopsy. Recent studies have suggested isolated FEA has a low association with carcinoma and these patients may warrant close surveillance. Isolated FEA has a low association with carcinoma in our series. These patients may not require surgical excision, but instead have close surveillance. Published by Elsevier Inc.

  15. Evolving concepts in the management of lobular neoplasia.

    PubMed

    Anderson, Benjamin O; Calhoun, Kristine E; Rosen, Eric L

    2006-05-01

    Lobular neoplasia broadly defines the spectrum of changes within the lobule, ranging from atypical lobular hyperplasia (ALH) to lobular carcinoma in situ (LCIS). This continuum of lesions is associated with an increased risk for developing subsequent invasive breast cancer, with the magnitude of that risk corresponding to the degree of proliferative change. The associated risk for developing invasive breast cancer after a diagnosis of lobular neoplasia is multicentric, bilateral, and equal in both breasts. Lobular neoplasia itself may transform into invasive carcinoma, although the frequency of this occurrence is unknown. Thus, lobular neoplasia is a risk factor for invasive breast cancer and may be a precursor lesion in unusual circumstances. The management of ALH and LCIS depends on the setting in which they are encountered. When ALH and LCIS are diagnosed after core needle breast biopsy, wire localization for surgical excision is required for definitive diagnosis because rates of histologic underestimation approach those of atypical ductal hyperplasia (ADH). When diagnosed on surgical biopsy, ALH and LCIS generally do not require further intervention, even when present at a surgical margin. However, bilateral breast cancer risk must be considered, especially when patients have a family history of breast cancer. In selected situations, bilateral prophylactic mastectomy with or without reconstruction may be considered when atypical hyperplasia or LCIS is diagnosed. Although this reduces risk for developing subsequent breast carcinoma by 90%, patients selected for prophylactic mastectomy represent a small subgroup of lobular neoplasia patients and generally have other risk factors, such as strong family history or evidence of genetic predisposition.

  16. Influence of feeding supplements of almond hulls and ensiled citrus pulp on the milk production, milk composition, and methane emissions of dairy cows.

    PubMed

    Williams, S R O; Chaves, A V; Deighton, M H; Jacobs, J L; Hannah, M C; Ribaux, B E; Morris, G L; Wales, W J; Moate, P J

    2018-03-01

    Almond hulls and citrus pulp have been fed to dairy cows with variable responses for milk production, but no information exists on their effect on enteric methane emissions. This experiment examined the effects of dietary supplementation with either almond hulls or ensiled citrus pulp on the milk yield, milk composition, and enteric methane emissions of dairy cows. Thirty-two Holstein dairy cows in mid lactation were offered 1 of 3 diets over a 28-d experiment. Twelve cows received a control (CON) diet, 10 cows a diet containing almond hulls (ALH), and 10 cows a diet containing ensiled citrus pulp (CIT). All cows were offered 6.0 kg of dry matter (DM)/d of crushed corn, 2.0 kg of DM/d of cold-pressed canola, and 0.2 kg of DM/d of a mineral mix. In addition, cows fed the CON diet were offered 14.5 kg of DM/d of alfalfa cubes; cows fed the ALH diet were offered 10.5 kg of DM/d of alfalfa cubes and 4.0 kg of DM/d of almond hulls; and cows on the CIT diet were offered 11.5 kg of DM/d of alfalfa cubes and 3.0 kg of DM/d of ensiled citrus pulp. Milk yield was measured daily and milk composition was measured on 4 d of each week. Individual cow methane emissions were measured by a sulfur hexafluoride tracer technique on d 24 to 28 of the experiment. The mean milk yield of cows fed the CON diet (27.4 kg/d) was greater than the mean milk yield of cows fed the ALH diet (24.6 kg/cow per day), whereas the mean milk yield of cows fed the CIT diet (26.2 kg/cow per day) was not different from the mean milk yield from cows fed the other 2 diets. Dietary treatment did not influence the concentrations of milk fat, protein, and lactose or fat yields, but the mean protein yield from cows fed the CON diet (0.87 kg/d) was greater than that from cows fed the ALH diet (0.78 kg/d) but not different to those fed the CIT diet (0.85 kg/d). In general, we found no differences in the proportion of individual fatty acids in milk. The mean pH of ruminal fluid from cows offered the CON diet was not

  17. Contribution of Organic Material to the Stable Isotope Composition of Some Terrestrial Carbonates as Analogs for Martian Processes

    NASA Technical Reports Server (NTRS)

    Socki, Richard A.; Gibson, Everett K., Jr.; Bissada, K. K.

    2005-01-01

    Understanding the isotopic geochemistry of terrestrial carbonate formation is essential to understanding the evolution of the Martian atmosphere, hydrosphere, and potential biosphere. Carbonate minerals, in particular, are important secondary minerals for interpreting past aqueous environments, as illustrated by the carbonates present in ALH84001 [1]. Models for the history of Mars suggest that the planet was warmer, wetter, and possessed a greater atmospheric pressure within the first billion years as compared to present conditions [2],[3],[4], and likely had an active hydrologic cycle. Morse and Marion [5] point out that associated with this hydrologic cycle would be the active chemical weathering of silicate minerals and thus consumption of atmospheric CO2 and deposition of carbonate and silica. It is during this warmer and wetter period of Martian history that surface and/or near-surface conditions would be most favorable for harboring possible microbiological life. Carbonates within ALH84001 offer evidence that fluids were present at 3.9 Gy on Mars [6]. A more through understanding of the effects of aqueous weathering and the potential contribution of organic compounds on the isotopic composition of Martian carbonate minerals can be gained by studying some terrestrial occurrences of carbonate rocks.

  18. Low-pressure Structural Modification of Aluminum Hydride

    DTIC Science & Technology

    2011-02-01

    Acknowledgments Use of the National Synchrotron Light Source (NSLS), Brookhaven National Laboratory ( BNL ) was supported by the U.S. Department of Energy...National Synchrotron Light Source (NSLS) of Brookhaven National Laboratory ( BNL ). The spectral resolution of ±4 cm–1 was used for all IR measurements...12 List of Symbols, Abbreviations, and Acronyms Al aluminum AlH3 aluminum hydride BNL Brookhaven National Laboratory EOS equation of

  19. Functional anion concept: effect of fluorine anion on hydrogen storage of sodium alanate.

    PubMed

    Yin, Li-Chang; Wang, Ping; Kang, Xiang-Dong; Sun, Cheng-Hua; Cheng, Hui-Ming

    2007-03-28

    Doping NaAlH(4) with Ti-catalyst has produced a promising hydrogen storage system that can be reversibly operated at moderate temperature conditions. Of the various dopant precursors, TiCl(3) was well recognized due to its pronounced catalytic effect on the reversible dehydrogenation processes of sodium aluminium hydrides. Quite recently we experimentally found that TiF(3) was even better than TiCl(3) in terms of the critical hydrogen storage properties of the doped hydrides, in particular the dehydriding performance at Na(3)AlH(6)/NaH + Al step at moderate temperature. We present here the DFT calculation results of the TiF(3) or TiCl(3) doped Na(3)AlH(6). Our computational studies have demonstrated that F(-) and Cl(-) anions differ substantially from each other with regard to the state and function in the doped sodium aluminium hydride. In great contrast to the case of chloride doping where Cl(-) anion constitutes the "dead weight" NaCl, the fluoride doping results in a substitution of H(-) by F(-) anion in the hydride lattice and accordingly, a favorable thermodynamics adjustment. These results well explain the observed dehydriding performance associated with TiF(3)/TiCl(3)-doping. More significantly, the coupled computational and experimental efforts allow us to put forward a "functional anion" concept. This renews the current mechanism understanding in the catalytically enhanced sodium alanate.

  20. An ion microprobe study of CAIs from CO3 meteorites. [Abstract only

    NASA Technical Reports Server (NTRS)

    Russell, S. S.; Greenwood, R. C.; Fahey, A. J.; Huss, G. R.; Wasserburg, G. J.

    1994-01-01

    When attempting to interpret the history of Ca, Al-rich inclusions (CAIs) it is often difficult to distinguish between primary features inherited from the nebula and those produced during secondary processing on the parent body. We have undertaken a systematic study of CAIs from 10 CO chondrites, believed to represent a metamorphic sequence with the goal of distinguishing primary and secondary features. ALHA 77307 (3.0), Colony (3.0), Kainsaz (3.1), Felix (3.2), ALH 82101 (3.3), Ornans (3.3), Lance (3.4), ALHA 77003 (3.5), Warrenton (3.6), and Isna (3.7) were examined by Scanning Electron Microscopy (SEM) and optical microscopy. We have identified 141 CAIs within these samples, and studied in detail the petrology of 34 inclusions. The primary phases in the lower petrologic types are spinel, melilite, and hibonite. Perovskite, FeS, ilmenite, anorthite, kirschsteinite, and metallic Fe are present as minor phases. Melilite becomes less abundant in higher petrologic types and was not detected in chondrites of type 3.5 and above, confirming previous reports that this mineral easily breaks down during heating. Iron, an element that would not be expected to condense at high temperatures, has a lower abundance in spinel from low-petrologic-type meteorites than those of higher grade, and CaTiO3 is replaced by FeTiO3 in meteorites of higher petrologic type. The abundance of CAIs is similar in each meteorite. Eight inclusions have been analyzed by ion probe. The results are summarized. The results obtained to date show that CAIs in CO meteorites, like those from other meteorite classes, contain Mg* and that Mg in some inclusions has been redistributed.

  1. Surgical upgrade rate of breast atypia to malignancy: An academic center's experience and validation of a predictive model.

    PubMed

    Linsk, Ali; Mehta, Tejas S; Dialani, Vandana; Brook, Alexander; Chadashvili, Tamuna; Houlihan, Mary Jane; Sharma, Ranjna

    2018-03-01

    Atypical ductal hyperplasia (ADH), atypical lobular hyperplasia (ALH), and lobular carcinoma in situ (LCIS) are commonly seen on breast core needle biopsy (CNB). Many institutions recommend excision of these lesions to exclude malignancy. A retrospective chart review was performed on patients who had ADH, ALH, or LCIS on breast CNB from 1/1/08 to 12/31/10 who subsequently had surgical excision of the biopsy site. Study objectives included determining upgrade to malignancy at surgical excision, identification of predictors of upgrade, and validation of a recently published predictive model. Clinical and demographic factors, pathology, characteristics of the biopsy procedure and visible residual lesion were recorded. T test and chi-squared test were used to identify predictors. Classification tree was used to predict upgrade. 151 patients had mean age of 53 years. The mean maximum lesion size on imaging was 11 mm. The primary atypia was ADH in 63.6%, ALH in 27.8%, and LCIS in 8.6%. 16.6% of patients had upgrade to malignancy, with 72% DCIS and 28% invasive carcinoma. Risk factors for upgrade included maximum lesion size (P = .002) and radiographic presence of residual lesion (P = .001). A predictive model based on these factors had sensitivity 78%, specificity 80% and AUC = 0.88. Validating a published nomogram with our data produced accuracy figures (AUC = 0.65) within published CI of 0.63-0.82. In CNB specimens containing ADH, ALH, or LCIS, initial lesion size and presence of residual lesion are predictors of upgrade to malignancy. A validated model may be helpful in developing patient management strategies. © 2017 Wiley Periodicals, Inc.

  2. Candidates source regions of martian meteorites as identified by OMEGA/MEx

    NASA Astrophysics Data System (ADS)

    Ody, A.; Poulet, F.; Quantin, C.; Bibring, J.-P.; Bishop, J. L.; Dyar, M. D.

    2015-09-01

    The objective of this study is to identify and map spectral analogues of some key martian meteorites (basaltic shergottites Los Angeles, Shergotty, QUE 94201, lherzolitic shergottite ALH A77005, Nakhla, Chassigny and the orthopyroxenite ALH 84001) in order to localize terrain candidates for their source regions. We develop a best fit procedure to reproduce the near-infrared (NIR) spectral properties of the martian surface as seen by the hyperspectral imaging spectrometer OMEGA/MEx from the NIR spectra of the martian meteorites. The fitting process is tested and validated, and Root Mean Square (RMS) global maps for each meteorite are obtained. It is found that basaltic shergottites have NIR spectral properties the most representative of the martian surface with the best spectral analogues found in early Hesperian volcanic provinces. Sites with spectral properties similar to those of ALH A77005 are scarce. They are mainly localized in olivine-bearing regions such as Nili Fossae and small Noachian/early Hesperian terrains. The only plausible source region candidate for Chassigny is the Nili Patera caldera dated to 1.6 Ga. Widespread spectral analogues for the ALH 84001 meteorite are found northeast of Syrtis Major and northwest of the Hellas basin. While this distribution is in agreement with the low-calcium-pyroxene-rich composition and old age (4.1 Ga) of this meteorite, the modal mineralogy of these candidates is not consistent with that of this meteorite. No convincing spectral analogue is found for the Amazonian-aged Nakhla meteorite suggesting that its olivine/high-calcium-pyroxene-rich composition could be representative of the Amazonian terrains buried under dust. Finally, some young rayed craters are proposed as possible candidates for source craters of the studied martian meteorites.

  3. [Angiolymphoid hyperplasia with eosinophilia with bilateral involvement of the lacrimal glands].

    PubMed

    Baráková, Drahomíra; Sâch, Josef; Kuchynka, Pavel; Rêdinová, Magdalena; Kocur, Ivo

    2002-05-01

    Angiolymphoid hyperplasia with eosinophilia (ALHE) and Kimura's disease are two rarely occurring disorders very similar to each other; however, they are individual nosological entities. For a long time they were considered as a single disease due to the frequency of similar characteristics. The majority of authors have recently considered these diseases as two individual entities with some reciprocal specifications, both clinical as well as morphological. We report on the case of a 76-year old male white European who had suffered for more than six years from subcutaneous tumour formations in different parts of the body. Eyelid oedema on the right side with palpable resistance under the upper temporal edge of the orbit initially occurred five years after the first symptoms of the disease. A similar finding occurred on the left side after eight months. The tumours on both sides were surgically removed and sent for histological analysis. A unilateral recurrence of the finding appeared after one year, followed by surgical intervention and histological examination. Tumour infiltrate in the first two orbita excisions was topically related to lacrimal gland structures; these structures were not found in the third excision. The case was histologically diagnosed as ALHE despite some similar characteristics with Kimura's disease. The diagnosis of ALHE was histologically supported, especially by the absence of lymphatic follicle formations and fibrotisation in the infiltrate, and the identification of the appearance of epitheloid up to histiocytoid of proliferating endothelium, which forms small lumens. The diagnosis of ALHE was additionally supported by the fact that the incidence of Kimura's disease in white Europeans is very rare. According to our findings, both entities overlap one another, even in some characteristics considered to be distinguishing. The question arises, therefore, whether the strict separation of these nosological entities can indeed be determined with

  4. House Dust Endotoxin and Peripheral Leukocyte Counts: Results from Two Large Epidemiologic Studies

    PubMed Central

    Carnes, Megan U.; Salo, Päivi M.; Wilkerson, Jesse; Cohn, Richard D.; King, Debra; Hoppin, Jane A.; Sandler, Dale P.; Travlos, Greg; London, Stephanie J.; Thorne, Peter S.; Zeldin, Darryl C.

    2017-01-01

    Background: The peripheral leukocyte count is a biomarker of inflammation and is associated with human all-cause mortality. Although causes of acute leukocytosis are well-described, chronic environmental determinants of leukocyte number are less well understood. Objectives: We investigated the relationship between house dust endotoxin concentration and peripheral leukocyte counts in human subjects. Methods: The endotoxin–leukocyte relationship was evaluated by linear regression in the National Health and Nutrition Examination Survey (NHANES) 2005–2006 (n=6,254) and the Agricultural Lung Health Study (ALHS; n=1,708). In the ALHS, we tested for a gene [Toll-like Receptor 4 (TLR4), encoding the endotoxin receptor]-by-environment interaction in the endotoxin–leukocyte relationship using regression models with an interaction term. Results: There is a statistically significant, positive association between endotoxin concentration and total leukocyte number [estimated change, 0.186×103/μL (95% CI: 0.070, 0.301×103/μL) per 10-fold change in endotoxin; p=0.004) in the NHANES. Similar positive associations were found for monocytes, lymphocytes, and neutrophils. Stratified analyses revealed possible effect modification by asthma and chronic obstructive pulmonary disease. We observed similar associations in the ALHS. For total leukocytes, there was suggestive evidence in the ALHS of a gene-by-environment interaction for minor allele carrier status at the TLR4 haplotype defined by rs4986790 and rs4986791 (interaction p=0.15). Conclusions: This is, to our knowledge, the first report of an association between house dust endotoxin and leukocyte count in a national survey. The finding was replicated in a farming population. Peripheral leukocyte count may be influenced by residential endotoxin exposure in diverse settings. https://doi.org/10.1289/EHP661 PMID:28599265

  5. DNA methylation in a Scottish family multiply affected by bipolar disorder and major depressive disorder.

    PubMed

    Walker, Rosie May; Christoforou, Andrea Nikie; McCartney, Daniel L; Morris, Stewart W; Kennedy, Nicholas A; Morten, Peter; Anderson, Susan Maguire; Torrance, Helen Scott; Macdonald, Alix; Sussmann, Jessika Elizabeth; Whalley, Heather Clare; Blackwood, Douglas H R; McIntosh, Andrew Mark; Porteous, David John; Evans, Kathryn Louise

    2016-01-01

    Bipolar disorder (BD) is a severe, familial psychiatric condition. Progress in understanding the aetiology of BD has been hampered by substantial phenotypic and genetic heterogeneity. We sought to mitigate these confounders by studying a multi-generational family multiply affected by BD and major depressive disorder (MDD), who carry an illness-linked haplotype on chromosome 4p. Within a family, aetiological heterogeneity is likely to be reduced, thus conferring greater power to detect illness-related changes. As accumulating evidence suggests that altered DNA methylation confers risk for BD and MDD, we compared genome-wide methylation between (i) affected carriers of the linked haplotype (ALH) and married-in controls (MIs), (ii) well unaffected haplotype carriers (ULH) and MI, (iii) ALH and ULH and (iv) all haplotype carriers (LH) and MI. Nominally significant differences in DNA methylation were observed in all comparisons, with differences withstanding correction for multiple testing when the ALH or LH group was compared to the MIs. In both comparisons, we observed increased methylation at a locus in FANCI, which was accompanied by increased FANCI expression in the ALH group. FANCI is part of the Fanconi anaemia complementation (FANC) gene family, which are mutated in Fanconi anaemia and participate in DNA repair. Interestingly, several FANC genes have been implicated in psychiatric disorders. Regional analyses of methylation differences identified loci implicated in psychiatric illness by genome-wide association studies, including CACNB2 and the major histocompatibility complex. Gene ontology analysis revealed enrichment for methylation differences in neurologically relevant genes. Our results highlight altered DNA methylation as a potential mechanism by which the linked haplotype might confer risk for mood disorders. Differences in the phenotypic outcome of haplotype carriers might, in part, arise from additional changes in DNA methylation that converge on

  6. Remanent magnetic properties of unbrecciated eucrites

    NASA Technical Reports Server (NTRS)

    Cisowski, Stanley M.

    1991-01-01

    This study examines the remanent magnetic properties of five unbrecciated eucrites, ranging from the coarse-grained cumulate Moore County to the quenched melt rock ALH 81001 in order to assess the strength of the magnetic field associated with their parent body during their formation. Two of the meteorites are judged as unlikely to have preserved their primary thermal remanence because of large variations in subsample remanence intensity and direction (Ibitira), and lack of NRM resistance to AF and thermal demagnetization (PCA 82502). The lack of a strong (greater than 0.01 mT) magnetizing field during their cooling on the eucrite parent body is inferred from the low normalized NRM intensities for subsamples of ALH 81001 and Yamato 791195.

  7. Perspective of Family Members of Transitions to Alternative Levels of Care in Anglo-Saxon Countries.

    PubMed

    Merla, C; Wickson-Griffiths, A; Kaasalainen, S; Dal Bello-Haas, V; Banfield, L; Hadjistavropoulos, T; Di Sante, E

    2018-01-01

    This scoping review explores circumstances surrounding the decision about, and eventual experience of, transitioning older adults into alternative levels of housing (ALH), such as long-term care. This topic is examined from a family member perspective, given their exposure and involvement in the care of older adult relatives during this transitional period. The scoping review methodology is based on the framework of Arksey and O'Malley and subsequent recommendations from Levac, Colquhoun, and O'Brien. Approximately 470 articles were reviewed covering the period between 2000 and November 2014; 37 articles met inclusion criteria. A temporal organization of themes was used to describe the experiences of family members in the pretransition, active transition, and posttransition periods of moving older adult relatives into ALH. This paper highlights the transitional period as a time of crisis, with a lack of planning, support, and transparent discussion. This study identifies a need for future research on the potential benefits of family support groups, interim transitional housing options, different models of ALH, changing roles in the posttransition period, and the need for a comprehensive list of housing options for older adults. Results have the potential to inform policy/practice and improve the lives of older adults and their family.

  8. Lunar and Planetary Science XXXVI, Part 3

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Topics discussed include: Characterization of Non-Organized Soils at Gusev Crater with the Spirit Rover Data; Searching for Life with Rovers: Exploration Methods & Science Results from the 2004 Field Campaign of the "Life in the Atacama" Project and Applications to Future Mars Missions; Analysis of the Lunar Surface with Global Mineral and Mg-Number Maps ALH77005: The Magmatic History from Rehomogenized Melt Inclusions; New 70-cm Radar Mapping of the Moon; Cryptomare Deposits Revealed by 70-cm Radar; Construction of a PZT Sensor Network for Low and Hypervelocity Impact Detection; Palmer Quest: A Feasible Nuclear Fission "Vision Mission" to the Mars Polar Caps; Physical Properties of Volcanic Deposits on Venus from Radar Polarimetry; Science Alert Demonstration with a Rover Traverse Science Data Analysis System; Earth and Mars, Similar Features and Parallel Lives? Didactic Activities; Expected Constraints on Rhea s Interior from Cassini; Microbially Induced Precipitates: Examples from CO3, Si-, Mn- and Fe-rich Deposits; Li, B - Behavior in Lunar Basalts During Shock and Thermal Metamorphism: Implications for H2O in Martian Magmas; Evaluation of CO Self-Shielding as a Possible Mechanism for Anomalous Oxygen Isotopic Composition of Early Solar System Materials; Effect of Ground Ice on Apparent Thermal Inertia on Mars; Utah Marbles and Mars Blueberries: Comparative Terrestrial Analogs for Hematite Concretions on Mars; Newly Discovered Meteor Crater Metallic Impact Spherules: Report and Implications; and Evidence of Very Young Glacial Processes in Central Candor Chasma, Mars.

  9. Self-Defense by Any Other Name is Still Self-Defense

    DTIC Science & Technology

    2003-04-01

    Unlimited D D15Th3WON STAT13ENT L YNANNOUNIPV 03 JUSMIICATION BY DISTIBUTON/T AVAILABILIT CODES DIST1ZDtmN AVAILABILI AQM SPECI~ALH DATE ACCMSIONED...homeport? When the invasion force enters another state’s sovereign waters ? Is it as simplistic as which side fired the first shot? 34 These rhetorical...States’ sovereignty in her territorial waters and even led to the occasional killing of Whereas armed vessels sailing under authority or pretence of

  10. Possible Evidence for Life in ALH84001

    NASA Technical Reports Server (NTRS)

    McKay, David; Gibson, Everett K., Jr.; Thomas-Keprta, Kathie

    1999-01-01

    Since our original paper Science in August 1996, considerable new data has appeared from laboratories throughout the world, and our own team has had a chance to examine the sample in greater detail. The following summary touches on our original data and interpretation, and points out new data from us and from other groups, and the resulting changes and refinements in interpretations which we have made during the past three years.

  11. Porous, S-bearing silica in metal-sulfide nodules and in the interchondrule clastic matrix in two EH3 chondrites

    NASA Astrophysics Data System (ADS)

    Lehner, S. W.; Németh, P.; Petaev, M. I.; Buseck, P. R.

    2017-11-01

    Two new occurrences of porous, S-bearing, amorphous silica are described within metal-sulfide nodules (MSN) and as interchondrule patches in EH3 chondrites SAH 97072 and ALH 84170. This porous amorphous material, which was first reported from sulfide-bearing chondrules, consists of sinewy SiO2-rich areas containing S with minor Na or Ca as well as Fe, Mg, and Al. Some pores contain minerals including pyrite, pyrrhotite, and anhydrite. Most pores appear vacant or contain unidentified material that is unstable under analytical conditions. Niningerite, olivine, enstatite, albite, and kumdykolite occur enclosed within porous silica patches. Porous silica is commonly interfingered with cristobalite suggesting its amorphous structure resulted from high-temperature quenching. We interpret the S-bearing porous silica to be a product of silicate sulfidation, and the Na, Ca, Fe, Mg, and Al detectable within this material are chemical residues of sulfidized silicates and metal. The occurrence of porous silica in the cores of MSN, which are considered to be pre-accretionary objects, suggests the sulfidizing conditions occurred prior to final parent-body solidification. Ubiquitous S-bearing porous silica among sulfide-bearing chondrules, MSN, and in the interchondrule clastic matrix, suggests that similar sulfidizing conditions affected all the constituents of these EH3 chondrites.

  12. Sodium Chloride and Water Transport in the Medullary Thick Ascending Limb of Henle. EVIDENCE FOR ACTIVE CHLORIDE TRANSPORT

    PubMed Central

    Rocha, Antonino S.; Kokko, Juha P.

    1973-01-01

    Transport of NaCl and water was examined in the rabbit medullary thick ascending limb of Henle (ALH) by perfusing isolated segments of these nephrons in vitro. Osmotic water permeability was evaluated by perfusing tubules against imposed osmotic gradients. In these experiments the net transport of fluid remained at zero when segments of thick ALH were perfused with isotonic ultrafiltrate in a bath of rabbit serum in which the serum osmolality was increased by the addition of either 239±8 mosmol/liter of raffinose or 232±17 mosmol of NaCl indicating that the thick ascending limb of Henle is impermeant to osmotic flow of water. When these tubules were perfused at slow rates with isosmolal ultrafiltrate of same rabbit serum as used for the bath, the effluent osmolality was consistently lowered to concentrations less than the perfusate and the bath. That this decrease in collected fluid osmolality represented salt transport was demonstrated in a separate set of experiments in which it was shown that the sodium and chloride concentrations decreased to 0.79±0.02 and 0.77±0.02 respectively when compared with the perfusion fluid concentrations. In each instance the simultaneously determined transtubular potential difference (PD) revealed the lumen to be positive with the magnitude dependent on the perfusion rate. At flow rates above 2 nl·min-1, the mean transtubular PD was stable and equal to 6.70±0.34 mv. At stop-flow conditions this PD became more positive. Ouabain and cooling reversibly decreased the magnitude of this PD. The transtubular PD remained positive, 3.3±0.2 mV, when complete substitution of Na by choline was carried out in both the perfusion fluid and the bathing media. These results are interpreted to indicate that the active transport process is primarily an electrogenic chloride mechanism. The isotopic permeability coefficient for Na was 6.27±0.38 × 10-5 cm·s-1 indicating that the thick ALH is approximately as permeable to Na as the proximal

  13. The arcuate line hernia: operative treatment and a review of the literature.

    PubMed

    Montgomery, A; Petersson, U; Austrums, E

    2013-06-01

    An arcuate line hernia (ALH) is a rare diagnosis with no consensus on how to deal with this condition either when symptomatic or when found accidentally. Suggestions for laparoscopic and open operative techniques are given together with a review of the literature and a presentation of three new cases. The PubMed database was searched for publications on ALH. Identified cases, including three from our department, are reported. Five males and two females, with a median age of 53 years were identified. Three patients were correctly diagnosed on a preoperative CT scan and the rest at surgery. Two patients had bilateral ALHs and four had other concomitant hernias repaired. Small bowel was present in the hernia in three cases and sigmoid colon in one. In one case, an emergency operation was performed due to bowel incarceration. Five patients had laparoscopic repairs, three with mesh and two without. Two patients, one converted from laparoscopic to open operation, had open mesh repairs. The postoperative course was uneventful in all cases, and no recurrences have been reported at a median follow-up of 6 months. A laparoscopic approach is recommended for diagnostic purposes, for pre-peritoneal mesh placement and for repair of concomitant hernias in both elective and emergency settings. Highlighting its existence might help general surgeons in interpreting an unusual finding on a CT scan or at operation.

  14. Impact of the Geoplasma on a Spaceborne GPS(Global Positioning System) Receiver System - A Preliminary Study

    DTIC Science & Technology

    1989-02-28

    valug vhich *dvrivv the A044 1 hý’we not met with mucth suktflV. Klobutchsr Ot al (1987) have obtained ThC data for tho first ti=# "t a polar cap sit...ntudy in 1984. found teei s vaiblty int TE. as-pri trainsg of ehnmntof the -ardor of J-O1gtffs~ fltpt riqd4 al ghlort a; tpný mrl’seO Were nbtrvud... ALE ) THEN ENC - V3 * ZEC ELSE EAR - (SIN (P1(3) - ALH) * 2.92) **6 F3 - EXP (- EAR) "V3 - V3 * F3 F3 - 1.0 - F3C* C* S3 - SOLAR CYCLE FUNCTION IF(1.1

  15. Surgical excision of pure flat epithelial atypia identified on core needle breast biopsy.

    PubMed

    Prowler, Vanessa L; Joh, Jennifer E; Acs, Geza; Kiluk, John V; Laronga, Christine; Khakpour, Nazanin; Lee, M Catherine

    2014-08-01

    The biology of flat epithelial atypia (FEA) is still being investigated as its presence becomes more frequent on biopsy specimens. FEA is more commonly associated with malignancy when found in association with ADH, ALH or LCIS. Pure FEA is only upgraded to cancer in 3.2% of patients. Surgical excision of pure FEA found on core needle biopsy results in overtreatment in the vast majority of breast patients and may not be necessary. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Cumberland Falls chondritic inclusions. III - Consortium study of relationship to inclusions in Allan Hills 78113 aubrite

    NASA Astrophysics Data System (ADS)

    Lipschutz, Michael E.; Verkouteren, R. Michael; Sears, Derek W. G.; Hasan, Fouad A.; Prinz, Martin.; Weisberg, M. K.; Nehru, Cherukupalli E.; Delaney, Jeremy S.; Grossman, Lawrence; Boily, Michel

    1988-07-01

    The contents of Ag, Au, Bi, Cd, Co, Cs, Ga, In, Rb, Sb, Se, Te, Tl, U, and Zn in large chondritic clasts from the Cumbersand Falls aubrite were determined by radiochemical neutron activation analysis, and the results, together with the results of a mineralogical investigation, were compared with respective data obtained for three primitive inclusions from the ALH A78113 aubrite. The results indicated that the clasts from both aubrite sources constitute a single chondritic suite. The analyses data, together with the results of thermoluminescence data for Cumberland Falls chondritic inclusions and achondritic host, indicate that inclusions in Cumberland Falls and in ALH A78113 aubrite represent a primitive chondrite sample suite whose properties were established during primary nebular accretion and condensation over a broad redox range.

  17. Carbonates in the Martian meteorite Allan Hills 84001 formed at 18 ± 4 °C in a near-surface aqueous environment

    PubMed Central

    Halevy, Itay; Fischer, Woodward W.; Eiler, John M.

    2011-01-01

    Despite evidence for liquid water at the surface of Mars during the Noachian epoch, the temperature of early aqueous environments has been impossible to establish, raising questions of whether the surface of Mars was ever warmer than today. We address this problem by determining the precipitation temperature of secondary carbonate minerals preserved in the oldest known sample of Mars’ crust—the approximately 4.1 billion-year-old meteorite Allan Hills 84001 (ALH84001). The formation environment of these carbonates, which are constrained to be slightly younger than the crystallization age of the rock (i.e., 3.9 to 4.0 billion years), has been poorly understood, hindering insight into the hydrologic and carbon cycles of earliest Mars. Using “clumped” isotope thermometry we find that the carbonates in ALH84001 precipitated at a temperature of approximately 18 °C, with water and carbon dioxide derived from the ancient Martian atmosphere. Furthermore, covarying carbonate carbon and oxygen isotope ratios are constrained to have formed at constant, low temperatures, pointing to deposition from a gradually evaporating, subsurface water body—likely a shallow aquifer (meters to tens of meters below the surface). Despite the mild temperatures, the apparently ephemeral nature of water in this environment leaves open the question of its habitability. PMID:21969543

  18. Vacancy-mediated dehydrogenation of sodium alanate

    PubMed Central

    Gunaydin, Hakan; Houk, Kendall N.; Ozoliņš, Vidvuds

    2008-01-01

    Clarification of the mechanisms of hydrogen release and uptake in transition-metal-doped sodium alanate, NaAlH4, a prototypical high-density complex hydride, has fundamental importance for the development of improved hydrogen-storage materials. In this and most other modern hydrogen-storage materials, H2 release and uptake are accompanied by long-range diffusion of metal species. Using first-principles density-functional theory calculations, we have determined that the activation energy for Al mass transport via AlH3 vacancies is Q = 85 kJ/mol·H2, which is in excellent agreement with experimentally measured activation energies in Ti-catalyzed NaAlH4. The activation energy for an alternate decomposition mechanism via NaH vacancies is found to be significantly higher: Q = 112 kJ/mol·H2. Our results suggest that bulk diffusion of Al species is the rate-limiting step in the dehydrogenation of Ti-doped samples of NaAlH4 and that the much higher activation energies measured for uncatalyzed samples are controlled by other processes, such as breaking up of AlH4− complexes, formation/dissociation of H2 molecules, and/or nucleation of the product phases. PMID:18299582

  19. Microstructure and Thermal History of Metal Particles in CH Chondrites

    NASA Astrophysics Data System (ADS)

    Goldstein, J. I.; Jones, R. H.; Kotula, P. G.; Michael, J. R.

    2005-03-01

    This paper provides detailed microstructural and microchemical information at the nm to µm scale (SEM, EPMA, TEM, EBSD) for a select suite of metal particles in four CH chondrites, ALH 85085, PAT 91546, Acfer 214, NWA 739.

  20. Hydrogen Sorption Properties of Potassium Alanate

    NASA Astrophysics Data System (ADS)

    Matysina, Z. A.; Zaginaichenko, S. Yu.; Schur, D. V.; Zolotarenko, Al. D.; Zolotarenko, An. D.; Gabdulin, M. T.

    2018-06-01

    Molecular kinetic representations were used to develop the statistical theory of phase transformations of thermal decomposition of KAlH4 potassium alanate with formation of a more complex K3AlH6 alanate and KH potassium hydride and subsequent dehydrogenation of the latter accompanied with free hydrogen, pure potassium and aluminum yield. Temperature dependence of the emitted free hydrogen was established. Isotherms and isopleths were built. The possibility of hysteresis effect manifestation was established. The results of calculations were compared to the experimental data.

  1. What Were the Major Factors That Controlled Mineralogical Similarities and Differences of Basaltic, Lherzolitic and Clinopyroxentic Martian Meteorites Within Each Group

    NASA Technical Reports Server (NTRS)

    Mikouchi, T.; Miyamoto, M.; McKay, G. A.

    1998-01-01

    Twelve martian meteorites that have been re- covered so far are classified into five groups (basalt, lherzolite, clinopyroxenite, dunite, and orthopyroxenite) mainly from petrology and chemistry. Among them, the dunite and orthopyroxenite groups consist of only one meteorite each (dunite: Chassigny, orthopyroxenite: ALH 84001). The basalt group is the largest group and consists of four meteorites (Shergotty, Zagani, EETA 79001, and QUE 94201). The lherzolitic and clinopyroxenitic groups include three meteorites each (Lherzolite: ALH 77005, LEW 88516, and Y793605, clinopyroxenite: Nakhla, Governador Valadares, and Lafayette). These meteorites within each group are generally similar to the others, but none of them is paired with the others. In this abstract, we discuss the major factors that controlled mineralogical similarities and differences of basaltic, lherzolitic, and clinopyroxenitic meteorites within each group. This may help in understanding their petrogenesis and original locations on Mars in general.

  2. Xe-129 - Xe-128 and Ar-40 - Ar-39 chronology of two Antarctic enstatite meteorites

    NASA Technical Reports Server (NTRS)

    Honda, M.; Bernatowicz, T. J.; Podosek, F. A.

    1983-01-01

    Xe-129 - Xe-128 and Ar-40 - Ar-39 analyses has been performed on two Antarctic enstatite meteorites, the chondrite Y-691 and the aubrite (enstatite achondrite) ALH-78113. Both meteorites have complex Ar-40 - Ar-39 release patterns to which no unambiguous age assignment is possible. Both give apparently satisfactory Xe-129 - Xe-128 correlations corresponding to unusual ages. The I-Xe age of the chondrite Y-691 is 16 Ma after Bjurbole, not unusual for chondrites in general but 10 Ma later than previously known ages for enstatite chondrites. The I-Xe age of the aubrite ALH-78113 is 210 Ma after Bjurbole, the latest age (rather than a limit) so far observed by the I-Xe technique, but this age assignment must be considered tentative because of the possibility that it is significantly influenced by terrestrial I contamination.

  3. Modeling Continuous-Time Random Processes in Digital Computer Simulations of Physical Systems

    DTIC Science & Technology

    1986-08-27

    hf) + BD1QD1B31 + BD2QD2B62 + BD3QD3BZ3 + BD4QD4BZ4 (51) where ODk = E[NDk-_•k] for k = 1 to 4. Note that PD(ti+l) has four BDiQDiBZi terms, one from...3 , collecting terms, and rearrang- ing equation (95), results in (aUz 3 + a 2 z 2 + a3z + ag4)hBV(z)Xlz) , (96) z 4 - alhAz 3 - (1 + a2 hA)z 2 - a 3...approximate the Taylor series form of I(h,I)? To answer this question, expand equation (1ll) in a series form , collect terms and compare it to 1(hI) . EhA

  4. Breast Changes and Conditions

    Cancer.gov

    Breast changes include benign conditions and those that increase the risk of breast cancer. Symptoms and treatment of breast conditions such as ADH, ALH, cysts, DCIS, and LCIS are explained to women who may have received an abnormal mammogram finding.

  5. Exposure Histories of Calcalong Creek and LEW 88516 Meteorites

    NASA Astrophysics Data System (ADS)

    Nishiizumi, K.; Arnold, J. R.; Caffee, M. W.; Finkel, R. C.; Southon, J.

    1992-07-01

    We report here preliminary results of cosmogenic radionuclides in lunar meteorite Calcalong Creek and shergottite LEW 88516 for study of exposure histories. Table 1 shows ^36Cl and ^10Be results for these two meteorites along with previous measurements of ^36Cl and ^10Be of SNC meteorites. The AMS measurements were performed at LLNL. Measured ^36Cl activities, in dpm/kg meteorite, were normalized to the target element concentration, dpm/kg (8Ca+Fe), for comparison and shown in the table. The ^36Cl saturation activity is ~22 +- 2 dpm/kg (8Ca+Fe) for 4-pi irradiation. Calcalong Creek: This is the first lunar meteorite found outside Antarctica (Hill et al., 1991; Marvin and Holmberg, 1992). ^36Cl and ^10Be activity levels are slightly (10-20%) higher than the production rate of these nuclides on the moon. One possibility is that the meteorite was ejected from near the surface (<70 g/cm^2) of the moon and transferred to the earth. The transition time from moon to earth was ~0.2 My. The other simple case is that the meteorite was ejected from deep (at least a few meters) in the moon, like Yamato 82192, and exposed to cosmic rays as a small body. The transition time in this case was ~2 My. The terrestrial age must be <70 ky for either case. Other cosmogenic nuclide measurements (in progress) are required to constrain the history further. LEW 88516: This meteorite was classified as a shergottite (Mason, 1991). The recovered mass is 13.2 g. We measured ^36Cl and ^10Be in 93.9 mg of homogenized bulk sample. All aspects of petrography and bulk chemical composition of LEW 88516 are remarkably similar to those of ALH 77005 (Boynton et al., 1992; Lindstrom et al., 1992). Since the ^10Be activities of ALH 77005 samples vary from 13.7 to 16.2 dpm/kg with increasing shielding depth (Nishiizumi et al., 1986a), the average of ^10Be in ALH 77005 is slightly lower than ^10Be in LEW 88516. The calculated ^10Be exposure age is ~3.0 My. The normalized ^36Cl activity of LEW 88516 is near

  6. Density functional theory study on aqueous aluminum-fluoride complexes: exploration of the intrinsic relationship between water-exchange rate constants and structural parameters for monomer aluminum complexes.

    PubMed

    Jin, Xiaoyan; Qian, Zhaosheng; Lu, Bangmei; Yang, Wenjing; Bi, Shuping

    2011-01-01

    Density functional theory (DFT) calculation is carried out to investigate the structures, (19)F and (27)Al NMR chemical shifts of aqueous Al-F complexes and their water-exchange reactions. The following investigations are performed in this paper: (1) the microscopic properties of typical aqueous Al-F complexes are obtained at the level of B3LYP/6-311+G**. Al-OH(2) bond lengths increase with F(-) replacing inner-sphere H(2)O progressively, indicating labilizing effect of F(-) ligand. The Al-OH(2) distance trans to fluoride is longer than other Al-OH(2) distance, accounting for trans effect of F(-) ligand. (19)F and (27)Al NMR chemical shifts are calculated using GIAO method at the HF/6-311+G** level relative to F(H(2)O)(6)(-) and Al(H(2)O)(6)(3+) references, respectively. The results are consistent with available experimental values; (2) the dissociative (D) activated mechanism is observed by modeling water-exchange reaction for [Al(H(2)O)(6-i)F(i)]((3-i)+) (i = 1-4). The activation energy barriers are found to decrease with increasing F(-) substitution, which is in line with experimental rate constants (k(ex)). The log k(ex) of AlF(3)(H(2)O)(3)(0) and AlF(4)(H(2)O)(2)(-) are predicted by three ways. The results indicate that the correlation between log k(ex) and Al-O bond length as well as the given transmission coefficient allows experimental rate constants to be predicted, whereas the correlation between log k(ex) and activation free energy is poor; (3) the environmental significance of this work is elucidated by the extension toward three fields, that is, polyaluminum system, monomer Al-organic system and other metal ions system with high charge-to-radius ratio.

  7. Modeling the contributions of phytoplankton and non-algal particles to spectral scattering properties in near-shore and lagoon waters

    NASA Astrophysics Data System (ADS)

    Vadakke-Chanat, Sayoob; Shanmugam, Palanisamy

    2017-03-01

    Particular attention was focused on modeling the spectral scattering properties of phytoplankton (bph(λ)) and non-algal particles (detrital organic and inorganic sediments bNAP(λ)) from absorption and attenuation measurements in near-shore and lagoon waters. The absorption line height (aLH(676)) measured above a linear background between 648 nm and 714 nm in particulate and dissolved organic matter absorption spectra (ap(λ)) is a spectral feature that is primarily associated with the chlorophyll with significantly less pigment package effect compared to the blue peak, and hence it is solely attributed to the phytoplankton absorption (aph). The correlation of aph(λ) with bph(λ) in terms of the spectral shape and the relation of aLH(676) with chlorophyll concentration hold the key to derive bph(648) from the aLH(676) measurements. bNAP(648) values are then determined by subtracting the bph(648) from bp(648), allowing the power-law model to derive the bNAP(λ). In-situ determination of bph (λ) is subsequently achieved by subtracting the featureless bNAP(λ) from bp(λ) provided by the ac-s sensor. These data form the basis for the development of models for independent estimates of bph(λ) and bNAP(λ) based on the measurements of aLH and suspended sediment concentration or turbidity. The validity of this method was demonstrated in a wide variety of samples from coastal and inland environments. Comparison of the modeled and measured spectral variations of bph(λ) showed the mean relative percent difference between these two data to be within 20%. bNAP(λ) predictions also had an error a few percent and the correlation coefficient close to unity. When comparing the modeled bph(λ) with laboratory culture data, the results were exceptionally good although discrepancies in size and refractive index of cells of monospecific lab culture samples and natural assemblages due to the simultaneous presence of different species. The proposed approach and models are highly

  8. Bulk Diffusion via a ``kick-out'' method for Lithium in the decomposition reaction LiAlH4/Li3AlH6

    NASA Astrophysics Data System (ADS)

    Rolih, Biljana; Ozolins, Vidvuds; Ozolins Team

    2013-03-01

    In the pursuit to find a practical system for hydrogen storage, complex metal hydrides have long been considered as viable candidates due to their high hydrogen content. However, some of the challenges faced with these types of systems are poor thermodynamics or kinetics. The underlying mechanisms, and their limiting processes, for the decomposition of these materials need to be understood. From experimental work on the decomposition of hydrogen storage materials, it has been suggested that bulk diffusion of metal species is the bottleneck for hydrogen release. In this work is the dehydrogenation we investigated the system LiAlH4  LiAlH6 with favorable hydrogen release (5.3 wt %), at moderate temperatures. Using first-principles density functional theory we found the defects facilitating mass transport by calculating individual formation energies, highest concentrations, and activation barriers for defect mobility. The mass transport of Lithium is found to be mediated by a ``kick-out'' mechanism. The results are used to further our understanding of the fundamental mechanism of mass transport and evaluate the possibility of kinetics as the limiting process in this reaction.

  9. Effect of separate and combined exposure of selenium and diazinon on rat sperm motility by computer assisted semen analysis.

    PubMed

    Toman, Robert; Hluchy, Svatoslav; Cabaj, Michal; Massanyi, Peter; Roychoudhury, Shubhadeep; Tunegova, Martina

    2016-12-01

    Effects of selenium (Se) and diazinon (DZN) on sperm motility parameters in rats were investigated. Male rats received a separate dose of Se (2mgkg -1 b.w., intraperitoneally, 5mgL -1 , per os in drinking water), diazinon (20mgkg -1 b.w., intraperitoneally, 40mgL -1 , per os in drinking water), and in combination (Se+DZN) with the same dosage as in the separate administration. 36h an intraperitoneal (i.p.) and after 90days of per oral (p.o.) exposure, thirteen parameters of sperm motility were evaluated using a Computer Assisted Sperm Analyzer (CASA). Almost all the evaluated sperm motility parameters significantly decreased in Se p.o. exposed groups. In the Se i.p. group decrease was noted only in beat cross frequency (BCF) and progressive motility. Significant decline in the sperm motility, progressive motility, BCF and increase in amplitude of lateral head displacement (ALH) were recorded after DZN i.p. administration. In DZN p.o. group, significant increase in ALH, velocity average path (VAP) and curvilinear velocity (VCL) but decrease in progressive motility and BCF was detected. Se+DZN i.p. administration caused a significant decrease in motility, progressive motility and BCF. Per oral administration of Se+DZN decreased all motility parameters except LIN, WOB and ALH. Sperm abnormalities increased in all experimental conditions. Se and DZN negatively affected sperm structure and function in separate doses or in combination. No protective effect of Se was observed. Copyright © 2016 Elsevier GmbH. All rights reserved.

  10. Ameliorative Effect of Hexane Extract of Phalaris canariensis on High Fat Diet-Induced Obese and Streptozotocin-Induced Diabetic Mice

    PubMed Central

    Perez Gutierrez, Rosa Martha; Madrigales Ahuatzi, Diana; Horcacitas, Maria del Carmen; Garcia Baez, Efren; Cruz Victoria, Teresa; Mota-Flores, Jose Maria

    2014-01-01

    Obesity is one of the major factors to increase various disorders like diabetes. The present paper emphasizes study related to the antiobesity effect of Phalaris canariensis seeds hexane extract (Al-H) in high-fat diet- (HFD-) induced obese CD1 mice and in streptozotocin-induced mild diabetic (MD) and severely diabetic (SD) mice.AL-H was orally administered to MD and SD mice at a dose of 400 mg/kg once a day for 30 days, and a set of biochemical parameters were studied: glucose, cholesterol, triglycerides, lipid peroxidation, liver and muscle glycogen, ALP, SGOT, SGPT, glucose-6-phosphatase, glucokinase, hexokinase, SOD, CAT, GSH, GPX activities, and the effect on insulin level. HS-H significantly reduced the intake of food and water and body weight loss as well as levels of blood glucose, serum cholesterol, triglyceride, lipoprotein, oxidative stress, showed a protective hepatic effect, and increased HDL-cholesterol, serum insulin in diabetic mice. The mice fed on the high-fat diet and treated with AL-H showed inhibitory activity on the lipid metabolism decreasing body weight and weight of the liver and visceral adipose tissues and cholesterol and triglycerides in the liver. We conclude that AL-H can efficiently reduce serum glucose and inhibit insulin resistance, lipid abnormalities, and oxidative stress in MD and SD mice. Our results demonstrate an antiobesity effect reducing lipid droplet accumulation in the liver, indicating that its therapeutic properties may be due to the interaction plant components soluble in the hexane extract, with any of the multiple targets involved in obesity and diabetes pathogenesis. PMID:24523819

  11. Organic Carbon Exists in Mars Meteorites: Where is it on the Martian Surface?

    NASA Technical Reports Server (NTRS)

    McKay, D. S.; Clemett, S. J.; Gibson, E. K., Jr.; Thomas-Keprta, K. L.; Wentworth, S. J.

    2010-01-01

    The search for organic carbon on Mars has been a major challenge. The first attempt was the Viking GC-MS in situ experiment which gave inconclusive results at two sites oil. After the discovery that the SNC meteorites were from Mars, reported C isotopic compositional information which suggested a reduced C component present in the Martian meteorites reported the presence of reduced C components (i.e., polycyclic aromatic hydrocarbons) associated with the carbonate globules in ALH84001. Jull et al. noted in Nakhla there was acid insoluble C component present with more than 75% of its C lacking any C-14, which is modern-day terrestrial carbon. This C fraction was believed to be either indigenous martian or ancient meteoritic carbon. Fisk et al. have shown textural evidence along with C-enriched areas within fractures in Nakhla and ALH84001. Westall et al. have shown the presence of a large irregular fragment of organic material completely embedded within a chip of ALH84001. Interior samples from the Naklnla SNC made available by the British Museum of Natural History, were analyzed. Petrographic examination of Nakhla showed evidence of fractures (approx.0.5 microns wide) filled with dark brown to black dendritic material with characteristics similar to those observed by. Iddingsite is also present along fractures in olivine. Fracture filling and dendritic material was examined by SEM-EDX, TEM-EDX, Focused Electron Beam microscopy, Laser Raman Spectroscopy, Nano-SIMS Ion Micro-probe, and Stepped-Combustion Static Mass Spectrometry. Observations from the first three techniques are discussed.

  12. Comparison of retinal vessel measurements using adaptive optics scanning laser ophthalmoscopy and optical coherence tomography.

    PubMed

    Arichika, Shigeta; Uji, Akihito; Ooto, Sotaro; Muraoka, Yuki; Yoshimura, Nagahisa

    2016-05-01

    We compared adaptive optics scanning laser ophthalmoscopy (AOSLO) and optical coherence tomography (OCT) vessel caliber measurements. AOSLO videos were acquired from 28 volunteers with healthy eyes. Artery measurements were made 0.5-1 disc diameters away from the optic disc margin. Individual segmented retinal arterial caliber was measured in synchronization with cardiac pulsation and averaged to obtain final horizontal retinal arterial caliber (ACH) and horizontal retinal arterial lumen (ALH). All OCT images were obtained with the Spectralis OCT, a spectral-domain OCT system. Vertical retinal arterial caliber (ACV) and vertical retinal arterial lumen (ALV) were measured on the same artery measured with AOSLO. Measurements made with the two imaging systems were compared. Average ACH, measured with AOSLO, was 123.4 ± 11.2 and average ALH was 101.8 ± 10.2 µm. Average ACV, measured with OCT, was 125.5 ± 11.4 and average ALV was 99.1 ± 10.6 µm. Both arterial caliber (r = 0.767, p < 0.0001) and arterial lumen (r = 0.81, p < 0.0001) measurements were significantly correlated between imaging modalities. Additionally, ACH and ACV were not significantly different (p = 0.16). However, ALH measurements were significantly higher than ALV measurements (p = 0.03). Vessel measurements made with AOSLO and OCT were well correlated. Moreover, plasma is visible and distinguishable from the retinal vessel wall in AOSLO images but not in OCT images. Therefore, AOSLO may measure vessel width more precisely than OCT.

  13. Aqueous Chemical Modeling of Sedimentation on Early Mars with Application to Surface-Atmosphere Evolution

    NASA Technical Reports Server (NTRS)

    Catling, David C.

    2004-01-01

    This project was to investigate models for aqueous sedimentation on early Mars from fluid evaporation. Results focused on three specific areas: (1) First, a fluid evaporation model incorporating iron minerals was developed to compute the evaporation of a likely solution on early Mars derived from the weathering of mafic rock. (2) Second, the fluid evaporation model was applied to salts within Martian meteorites, specifically salts in the nakhlites and ALH84001. Evaporation models were found to be consistent with the mineralogy of salt assemblages-anhydrite, gypsum, Fe-Mg-Ca carbonates, halite, clays-- and the concentric chemical fractionation of Ca-to Mg-rich carbonate rosettes in ALH84001. We made progress in further developing our models of fluid concentration by contributing to updating the FREZCHEM model. (3) Third, theoretical investigation was done to determine the thermodynamics and kinetics involved in the formation of gray, crystalline hematite. This mineral, of probable ancient aqueous origin, has been observed in several areas on the surface of Mars by the Thermal Emission Spectrometer on Mars Global Surveyor. The "Opportunity" Mars Exploration Rover has also detected gray hematite at its landing site in Meridiani Planum. We investigated how gray hematite can be formed via atmospheric oxidation, aqueous precipitation and subsequent diagenesis, or hydrothermal processes. We also studied the geomorphology of the Aram Chaos hematite region using Mars Orbiter Camera (MOC) images.

  14. Calculation of the 13C NMR shieldings of the C0 2 complexes of aluminosilicates

    NASA Astrophysics Data System (ADS)

    Tossell, J. A.

    1995-04-01

    13C NMR shieldings have been calculated using the random-phase-approximation, localized-orbital local-origins version of ab initio coupled Hartree-Fuck perturbation theory for CO 2 and and for several complexes formed by the reaction of CO 2 with molecular models for aluminosilicate glasses, H 3TOT'H3 3-n, T,T' = Si,Al. Two isomeric forms of the CO 2-aluminosilicate complexes have been considered: (1) "CO 2-like" complexes, in which the CO 2 group is bound through carbon to a bridging oxygen and (2) "CO 3-like" complexes, in which two oxygens of a central CO 3 group form bridging bonds to the two TH 3 groups. The CO 2-like isomer of CO 2-H 3SiOSiH 3 is quite weakly bonded and its 13C isotropic NMR shielding is almost identical to that in free CO 2. As Si is progressively replaced by Al in the - H terminated aluminosilicate model, the CO 2-like isomers show increasing distortion from the free CO 2 geometry and their 13C NMR shieldings decrease uniformly. The calculated 13C shielding value for H 3AlO(CO 2)AlH 3-2 is only about 6 ppm larger than that calculated for point charge stabilized CO 3-2. However, for a geometry of H 3SiO(CO 2) AlH 3-1, in which the bridging oxygen to C bond length has been artificially increased to that found in the - OH terminated cluster (OH) 3SiO(CO 2)Al(OH) 3-1, the calculated 13C shielding is almost identical to that for free CO 2. The CO 3-like isomers of the CO 2-aluminosili-cate complexes show carbonate like geometries and 13C NMR shieldings about 4-9 ppm larger than those of carbonate for all T,T' pairs. For the Si,Si tetrahedral atom pair the CO 2-like isomer is more stable energetically, while for the Si,Al and Al,Al cases the CO 3-like isomer is more stable. Addition of Na + ions to the CO 3-2 or H 3AlO(CO 2)AlH 3-2 complexes reduces the 13C NMR shieldings by about 10 ppm. Complexation with either Na + or CO 2 also reduces the 29Si NMR shieldings of the aluminosilicate models, while the changes in 27Al shielding with Na + or CO 2

  15. Fission Xenon on Mars

    NASA Technical Reports Server (NTRS)

    Mathew, K. J.; Marti, K.; Marty, B.

    2002-01-01

    Fission Xe components due to Pu-244 decay in the early history of Mars have been identified in nakhlites; as in the case of ALH84001 and Chassigny the fission gas was assimilated into indigenous solar-type Xe. Additional information is contained in the original extended abstract.

  16. Alteration of Rock Fragments from Columbia River Basalt Microcosms

    NASA Technical Reports Server (NTRS)

    Wentworth, Susan J.; Thomas-Keprta, Kathie L.; Velbel, Michael A.; McKay, David S.; Stevens, Todd O.

    1999-01-01

    During an earlier study, microorganisms were grown microcosms consisting of sterilized chips of Columbia River Basalt (CRB) and natural CRB ground water with its natural microflora; environmental conditions simulated a deep subsurface, anaerobic, dark environment. Subsequent scanning and transmission electron microscope (SEM and TEM) studies revealed the presence of several types of bacteria and biofilm, some of which were mineralized. Some of these biological features are very similar to possible biogenic features found in two meteorites from Mars, ALH84001 (found in Antarctica) and Nakhla (observed to fall in Egypt). Both ALH84001 and Nakhla contain traces of low-temperature aqueous alteration of silicates, oxides, and sulfides. The goals of this study are to use high-resolution field-emission SEM (FE-SEM) to examine the CRB samples for evidence of alteration features similar to those in the martian meteorites, to determine the extent of alteration during the CRB microcosm experiments, and to determine whether effects of biological activity can be distinguished from inorganic effects.

  17. Mars Life? - Orange-colored Carbonate Mineral Globules

    NASA Technical Reports Server (NTRS)

    1996-01-01

    This photograph shows orange-colored carbonate mineral globules found in a meteorite, called ALH84001, believed to have once been a part of Mars. These carbonate minerals in the meteorite are believed to have been formed on Mars more than 3.6 billion years ago. Their structure and chemistry suggest that they may have been formed with the assistance of primitive, bacteria-like living organisms. A two-year investigation by a NASA research team found organic molecules, mineral features characteristic of biological activity and possible microscopic fossils inside of carbonate minerals such as these in the meteorite.

  18. Mars Life? - Microscopic Tube-like Structures

    NASA Technical Reports Server (NTRS)

    1996-01-01

    This high-resolution scanning electron microscope image shows an unusual tube-like structural form that is less than 1/100th the width of a human hair in size found in meteorite ALH84001, a meteorite believed to be of Martian origin. Although this structure is not part of the research published in the Aug. 16 issue of the journal Science, it is located in a similar carbonate glob in the meteorite. This structure will be the subject of future investigations that could confirm whether or not it is fossil evidence of primitive life on Mars 3.6 billion years ago.

  19. Evaluation of Meterorite Amono Acid Analysis Data Using Multivariate Techniques

    NASA Technical Reports Server (NTRS)

    McDonald, G.; Storrie-Lombardi, M.; Nealson, K.

    1999-01-01

    The amino acid distributions in the Murchison carbonaceous chondrite, Mars meteorite ALH84001, and ice from the Allan Hills region of Antarctica are shown, using a multivariate technique known as Principal Component Analysis (PCA), to be statistically distinct from the average amino acid compostion of 101 terrestrial protein superfamilies.

  20. Spatial distribution analysis of the OMI aerosol layer height: a pixel-by-pixel comparison to CALIOP observations

    NASA Astrophysics Data System (ADS)

    Chimot, Julien; Pepijn Veefkind, J.; Vlemmix, Tim; Levelt, Pieternel F.

    2018-04-01

    A global picture of atmospheric aerosol vertical distribution with a high temporal resolution is of key importance not only for climate, cloud formation, and air quality research studies but also for correcting scattered radiation induced by aerosols in absorbing trace gas retrievals from passive satellite sensors. Aerosol layer height (ALH) was retrieved from the OMI 477 nm O2 - O2 band and its spatial pattern evaluated over selected cloud-free scenes. Such retrievals benefit from a synergy with MODIS data to provide complementary information on aerosols and cloudy pixels. We used a neural network approach previously trained and developed. Comparison with CALIOP aerosol level 2 products over urban and industrial pollution in eastern China shows consistent spatial patterns with an uncertainty in the range of 462-648 m. In addition, we show the possibility to determine the height of thick aerosol layers released by intensive biomass burning events in South America and Russia from OMI visible measurements. A Saharan dust outbreak over sea is finally discussed. Complementary detailed analyses show that the assumed aerosol properties in the forward modelling are the key factors affecting the accuracy of the results, together with potential cloud residuals in the observation pixels. Furthermore, we demonstrate that the physical meaning of the retrieved ALH scalar corresponds to the weighted average of the vertical aerosol extinction profile. These encouraging findings strongly suggest the potential of the OMI ALH product, and in more general the use of the 477 nm O2 - O2 band from present and future similar satellite sensors, for climate studies as well as for future aerosol correction in air quality trace gas retrievals.

  1. Reversible Dehydration Behavior Reveals Coordinatively Unsaturated Metal Sites in Microporous Aluminum Phosphonates

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

    Kinnibrugh, Tiffany L.; Bakhmutov, Vladimir I.; Clearfield, Abraham

    2014-10-01

    Incorporation of the same ligand into three different aluminum phenylenediphosphonates (Al(H 2O)(O 3PC 6H 4PO 3H) (1), Al-4(H 2O)(2)(O 3PC 6H 4PO 3)(3) (2), and Al-4(H 2O)(4)(O 3PC 6H 4PO 3)(2.84)(OH)(0.64) (3)) was accomplished by varying the synthetic conditions. The compounds have different sorption properties; however, all exhibit reversible dehydration behavior. The structures of the hydrated and dehydrated phases were determined from powder X-ray diffraction data. Compounds 2 and 3 were found to be microporous, while compound 1 was found to be nonporous. The stability of the dehydrated phase and the resulting porosity was found to be influenced by themore » change in the structure upon loss of water.« less

  2. Mars Life? - Microscopic Tube-like Structures

    NASA Image and Video Library

    1996-08-09

    This high-resolution scanning electron microscope image shows an unusual tube-like structural form that is less than 1/100th the width of a human hair in size found in meteorite ALH84001, a meteorite believed to be of Martian origin. http://photojournal.jpl.nasa.gov/catalog/PIA00288

  3. Rubidium-Strontium Formation Age of Allan Hills 84001 Carbonates

    NASA Technical Reports Server (NTRS)

    Borg, L. E.; Nyquist, L. E.; Shih, C.-Y.; Weismann, H.; Reese, Y.; Connelly, J. N.

    1998-01-01

    Our preferred age for the formation of carbonates in the martian meteorite ALH 84001 is 3.90 plus or minus 0.04 Ga for Lambda (Rubidium 87) equals 0.01402 Ga (exp -1), or 3.85 plus or minus 0.04 Ga for Lambda (Rubidium 87) = 0.0142 Ga(exponent -1). This age is determined by a three-point Rb-Sr isochron defined by leachates of high-graded carbonate-rich material. Major cation and especially phosphorous analyses of the leachates permit contributions from igneous whitlockite to be recognized for low-acidity leachates, and the corresponding data are omitted from the isochron. Data for the two highest acidity leachates plot close to the preferred isochron, but are omitted because we believe they contain contributions leached from the pyroxene substrate on which most of the carbonates are found. Nevertheless, the isochron age for all five highest-acidity leachates is 3.94 plus or minus 0.04 Ga, and is within error of the age obtained for the more restricted data set. All leachates used to define the isochron have major cation compositions that are singular to those obtained by microprobe analyses of the carbonate rosettes and are consistent with progressive digestion of the carbonates according to their composition. The age thus obtained for the carbonates is about 600 m.y. younger than the crystalization age of ALH 84001 determined by Sm-Nd analyses but is within error limits of the age of impact metamorphism inferred from the Rb-Sr and Ar-Ar systematics of silicates. which yield ages of 3.85 plus or minus 0.05 Ga and 4.05- 3.80 Ga to 4.3-3.8 Ga, respectively. Similarities between the carbonate crystallization age and the age of impact metamorphism as determined by Ar-Ar and Rb-Sr suggest that the carbonate formation is impact-related. Nevertheless, both high and low- temperature scenarios for the origin of the carbonates are possible.

  4. Chemical and physical studies of type 3 chondrites 12: The metamorphic history of CV chondrites and their components

    NASA Technical Reports Server (NTRS)

    Guimon, R. Kyle; Symes, Steven J. K.; Sears, Derek W. G.

    1995-01-01

    The induced thermoluminescence (TL) properties of 16 CV and CV-related chondrites, four CK chondrites and Renazzo (CR2) have been measured in order to investigate their metamorphic history. The petrographic, mineralogical and bulk compositional differences among the CV chondrites indicate that the TL sensitivity of the approximately 130 C TL peak is reflecting the abundance of ordered feldspar, especially in chondrule mesostasis, which in turn reflects parent-body metamorphism. The TL properties of 18 samples of homogenized Allende powder heated at a variety of times and temperatures, and cathodoluminescence mosaics of Axtell and Coolidge, showed results consistent with this conclusion. Five refractory inclusions from Allende, and separates from those inclusions, were also examined and yielded trends reflecting variations in mineralogy indicative of high peak temperatures (either metamorphic or igneous) and fairly rapid cooling. The CK chondrites are unique among metamorphosed chondrites in showing no detectable induced TL, which is consistent with literature data that suggests very unusual feldspar in these meteorites. Using TL sensitivity and several mineral systems and allowing for the differences in the oxidized and reduced subgroups, the CV and CV-related meteorites can be divided into petrologic types analogous to those of the ordinary and CO type 3 chondrites. Axtell, Kaba, Leoville, Bali, Arch and ALHA81003 are type 3.0-3.1, while ALH84018, Efremovka, Grosnaja, Allende and Vigarano are type 3.2-3.3 and Coolidge and Loongana 001 are type 3.8. Mokoia is probably a breccia with regions ranging in petrologic type from 3.0 to 3.2. Renazzo often plots at the end of the reduced and oxidized CV chondrite trends, even when those trends diverge, suggesting that in many respects it resembles the unmetamorphosed precursors of the CV chondrites. The low-petrographic types and low-TL peak temperatures of all samples, including the CV3.8 chondrites, indicates metamorphism

  5. Facile Synthesis and Superior Catalytic Activity of Nano-TiN@N-C for Hydrogen Storage in NaAlH4.

    PubMed

    Zhang, Xin; Ren, Zhuanghe; Lu, Yunhao; Yao, Jianhua; Gao, Mingxia; Liu, Yongfeng; Pan, Hongge

    2018-05-09

    Herein, we synthesize successfully ultrafine TiN nanoparticles (<3 nm in size) embedded in N-doped carbon nanorods (nano-TiN@N-C) by a facile one-step calcination process. The prepared nano-TiN@N-C exhibits superior catalytic activity for hydrogen storage in NaAlH 4 . Adding 7 wt % nano-TiN@N-C induces more than 100 °C reduction in the onset dehydrogenation temperature of NaAlH 4 . Approximately 4.9 wt % H 2 is rapidly released from the 7 wt % nano-TiN@N-C-containing NaAlH 4 at 140 °C within 60 min, and the dehydrogenation product is completely hydrogenated at 100 °C within 15 min under 100 bar of hydrogen, exhibiting significantly improved desorption/absorption kinetics. No capacity loss is observed for the nano-TiN@N-C-containing sample within 25 de-/hydrogenation cycles because nano-TiN functions as an active catalyst instead of a precursor. A severe structural distortion with extended bond lengths and reduced bond strengths for Al-H bonding when the [AlH 4 ] - group adsorbs on the TiN cluster is demonstrated for the first time by density functional theory calculations, which well-explains the reduced de-/hydrogenation temperatures of the nano-TiN@N-C-containing NaAlH 4 . These findings provide new insights into designing and synthesizing high-performance catalysts for hydrogen storage in complex hydrides.

  6. Thermally metamorphosed carbonaceous chondrites from data for thermally mobile trace elements

    NASA Astrophysics Data System (ADS)

    Wang, Ming-Sheng; Lipschutz, Michael E.

    1998-11-01

    We report RNAA data for U, Co, Au, Sb, Ga, Rb, Cs, Se, Ag, Te, Zn, In, Bi, Tl and Cd (ordered by increasing ease of vaporization and loss from Murchison CM2 chondrite during open-system heating) in 9 Antarctic C2 and C3 chondrites. These meteorites exhibit properties (obtained by reflectance spectroscopy, oxygen isotope mass spectrometry and/or mineralogy-petrology) suggesting thermal metamorphism in their parent bodies. Five of these (Asuka 881655, Yamato (Y) 793495, Y-790992, PCA 91008 and Y-86789, paired with Y-86720) exhibit significant depletion of the most thermally-mobile 1-5 trace elements consistent with open-system loss during extended parent body heating under conditions duplicated by week-long heating of Murchison C2 chondrite heated at 500-700 deg C in a low pressure (initially 10-5 atm) H atmosphere. From earlier data, three other C3 chondrites - Allan Hills (ALH) 81003, ALH 85003 and Lewis Cliffs 85332 - show significant Cd depletion. Nine additional C2 and C3 chondrites show no evidence of mobile trace element depletion - including Y-793321, which by all other criteria was mildly metamorphosed thermally. Either metamorphism of these nine occurred under closed conditions and/or alteration took place under such mild conditions that even Cd could not be lost. The RNAA data suggest that 10 of the 46 Antarctic carbonaceous chondrites (including 4 of 37 from Victoria Land and 6 of 9 from Queen Maud Land) exhibit open-system loss of at least some thermally mobile trace elements by heating in their parent bodies while none of the 25 non-Antarctic falls experienced this. These results are consistent with the idea that the Antarctic sampling of near-Earth material differs from that being sampled today.

  7. Lunar and Planetary Science XXXV: Astrobiology

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The presentations in this session are: 1. A Prototype Life Detection Chip 2. The Geology of Atlantis Basin, Mars, and Its Astrobiological Interest 3. Collecting Bacteria Together with Aerosols in the Martian Atmosphere by the FOELDIX Experimental Instrument Developed with a Nutrient Detector Pattern: Model Measurements of Effectivity 4. 2D and 3D X-ray Imaging of Microorganisms in Meteorites Using Complexity Analysis to Distinguish Field Images of Stromatoloids from Surrounding Rock Matrix in 3.45 Ga Strelley Pool Chert, Western Australia 4. Characterization of Two Isolates from Andean Lakes in Bolivia Short Time Scale Evolution of Microbiolites in Rapidly Receding Altiplanic Lakes: Learning How to Recognize Changing Signatures of Life 5. The Effect of Salts on Electrospray Ionization of Amino Acids in the Negative Mode 6. Determination of Aromatic Ring Number Using Multi-Channel Deep UV Native Fluorescence 7. Microbial D/H Fractionation in Extraterrestrial Materials: Application to Micrometeorites and Mars 8. Carbon Isotope Characteristics of Spring-fed Iron-precipitating Microbial Mats 9. Amino Acid Survival Under Ambient Martian Surface UV Lighting Extraction of Organic Molecules from Terrestrial Material: Quantitative Yields from Heat and Water Extractions 10. Laboratory Detection and Analysis of Organic Compounds in Rocks Using HPLC and XRD Methods 11. Thermal Decomposition of Siderite-Pyrite Assemblages: Implications for Sulfide Mineralogy in Martian Meteorite ALH84001 Carbonate Globules 12. Determination of the Three-Dimensional Morphology of ALH84001 and Biogenic MV-1 Magnetite: Comparison of Results from Electron Tomography and Classical Transmission Electron Microscopy 13. On the Possibility of a Crypto-Biotic Crust on Mars Based on Northern and Southern Ringed Polar Dune Spots 14. Comparative Planetology of the Terrestrial Inner Planets: Implications for Astrobiology 15. A Possible Europa Exobiology 16. A Possible Biogeochemical Model for Titan

  8. Rare Potassium-Bearing Mica in Allan Hills 84001: Additional Constraints on Carbonate Formation

    NASA Technical Reports Server (NTRS)

    Brearley, A. J.

    1998-01-01

    There have been presented several intriguing observations suggesting evidence of fossil life in martian orthopyroxenite ALH 84001. These exciting and controversial observations have stimulated extensive debate over the origin and history of ALH 84001, but many issues still remain unresolved. Among the most important is the question of the temperature at which the carbonates, which host the putative microfossils, formed. Oxygen- isotopic data, while showing that the carbonates are generally out of isotopic equilibria with the host rock, cannot constrain their temperature of formation. Both low- and high-temperature scenarios are plausible depending on whether carbonate growth occurred in an open or closed system. Petrographic arguments have generally been used to support a high-temperature origin but these appear to be suspect because they assume equilibrium between carbonate compositions that are not in contact. Some observations appear to be consistent with shock mobilization and growth from immiscible silicate-carbonate melts at high temperatures. Proponents of a low-temperature origin for the carbonates are hampered by the fact that there is currently no evidence of hydrous phases that would indicate low temperatures and the presence of a hydrous fluid during the formation of the carbonates. However, the absence of hydrous phases does not rule out carbonate formation at low temperatures, because the carbonate forming fluids may have been extremely CO2 rich, such that hydrous phases would not have been stabilized. In this study, I have carried out additional Transmission electron microscopy (TEM) studies of ALH-84001 and have found evidence of very rare phyllosilicates, which appear to be convincingly of pre-terrestrial origin. At present these observations are limited to one occurrence: further studies are in progress to determine if the phyllosilicates are more widespread.

  9. A robust robotic high-throughput antibody purification platform.

    PubMed

    Schmidt, Peter M; Abdo, Michael; Butcher, Rebecca E; Yap, Min-Yin; Scotney, Pierre D; Ramunno, Melanie L; Martin-Roussety, Genevieve; Owczarek, Catherine; Hardy, Matthew P; Chen, Chao-Guang; Fabri, Louis J

    2016-07-15

    Monoclonal antibodies (mAbs) have become the fastest growing segment in the drug market with annual sales of more than 40 billion US$ in 2013. The selection of lead candidate molecules involves the generation of large repertoires of antibodies from which to choose a final therapeutic candidate. Improvements in the ability to rapidly produce and purify many antibodies in sufficient quantities reduces the lead time for selection which ultimately impacts on the speed with which an antibody may transition through the research stage and into product development. Miniaturization and automation of chromatography using micro columns (RoboColumns(®) from Atoll GmbH) coupled to an automated liquid handling instrument (ALH; Freedom EVO(®) from Tecan) has been a successful approach to establish high throughput process development platforms. Recent advances in transient gene expression (TGE) using the high-titre Expi293F™ system have enabled recombinant mAb titres of greater than 500mg/L. These relatively high protein titres reduce the volume required to generate several milligrams of individual antibodies for initial biochemical and biological downstream assays, making TGE in the Expi293F™ system ideally suited to high throughput chromatography on an ALH. The present publication describes a novel platform for purifying Expi293F™-expressed recombinant mAbs directly from cell-free culture supernatant on a Perkin Elmer JANUS-VariSpan ALH equipped with a plate shuttle device. The purification platform allows automated 2-step purification (Protein A-desalting/size exclusion chromatography) of several hundred mAbs per week. The new robotic method can purify mAbs with high recovery (>90%) at sub-milligram level with yields of up to 2mg from 4mL of cell-free culture supernatant. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. [Shall all lobular intraepithelial neoplasia diagnosed on image-guided biopsy require a surgical management?].

    PubMed

    Fischer-Hunsinger, Maeva; Guinebretière, Jean-Marc; Lasry, Serge; Langer, Adriana; Berment, Hélène; Nekka, Ibtissem; Nodiot, Philippe; Cherel, Pascal

    2016-05-01

    Lobular intraepithelial neoplasia (LIN) diagnosed on image-guided biopsy may be associated with an undiagnosed cancer. This is called under-diagnosis. The consequence is that management of these lesions is often surgical. But many surgeries finally are unnecessary. The aim of our study was to define criteria to avoid unnecessary surgery. This is a single-center, retrospective after a database collected prospectively study. Fourteen thousand biopsies were analyzed, including 456 diagnosed NLI. Under-diagnosis rates were analyzed according to many criteria. The average duration of following was 45 months. For atypical lobular hyperplasia (ALH), we obtained 7.6% under-diagnosis and combining several criteria, we got a low risk of cancer (2%). For LCIS, this rate was 23% and any low-risk group could be identified. ALH with calcifications≤20 mm, without any atypical lesion associated, histologically focal and whose removal is representative may be safely observed. For other LIN, surgery remains indicated. Copyright © 2016 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.

  11. U.S. EPA, Pesticide Product Label, MYCOTROL ES, 11/13/2008

    EPA Pesticide Factsheets

    2011-04-21

    ... rL"plr~iI,'r Ille·l·tillg .\\iII)SI I sl~llldards nfa( kast R-'):'i or Pl)5. Rq)~alCd L'XpOSUI\\' III hit!h l'PllcL'llIr:lliull:' pI" 1l1l .... Ttihl:!I 111"1)IL'II1:-. (:llll';ltl:-'l' alh . ...

  12. Search for fullerenes in stone meteorites

    NASA Astrophysics Data System (ADS)

    Oester, M. Y.; Kuechl, D.; Sipiera, P. P.; Welch, C. J.

    1994-07-01

    The possibility of identifying fullerenes in stony meteorites became apparent from a paper given by Radicati de Brozolo. In this paper it was reported that fullerenes were present in the debris resulting from a collision between a micrometeoroid and an orbiting satellite. This fact generated sufficient curiosity to initiate a search for the presence of fullerenes in various stone meteorites. In the present study seven ordinary chondrites (al-Ghanim L6 (find), Dimmitt H4 (find), Lazbuddie LL5 (find), New Concord H5 (fall), Silverton H4 (find), Springlake L6 (find), and Umbarger L3/6 (find)). Four carbonaceous chondrites (ALH 83100 C2 (find), ALH 83108 C30 (find), Allende CV3 (fall), and Murchison CM2 (fall), and one achondrite (Monticello How (find)) were analyzed for the presence of fullerenes. The analytical procedure employed was as follows: 100 mg of meteorite was ground up with a mortar and pestle; 10 mL of toluene was then added and the mixture was refluxed for 90 min; this mixture was then filtered through a short column of silica; a 50 microliter sample was then analyzed by high pressure liquid chromatography (HPLC) using a Buckyclutcher I column with a mobile phase consisting of equal volumes of toluene and hexane at a flow rate of 1.00 mg per minute, with detection at 330 and 600 nm. Three of the meteorites, Allende, Murchison, and al-Ghanim, gave HPLC traces containing peaks with similar retention times to the HPLC trace of an authentic fullerene C60. However, further analysis using an HPLC instrument equipped with a diode-array detector failed to confirm any of the substances detected in the three meteorites as C60. Additional analyses will be conducted to identify what the HPLC traces actually represent.

  13. Fine-Grained Rims in the Allan Hills 81002 and Lewis Cliff 90500 CM2 Meteorites: Their Origin and Modification

    NASA Technical Reports Server (NTRS)

    Hua, X.; Wang, J.; Buseck, P. R.

    2002-01-01

    Antarctic CM meteorites Allan Hills (ALH) 8 1002 and Lewis Cliff (LEW) 90500 contain abundant fine-grained rims (FGRs) that surround a variety of coarse-grained objects. FGRs from both meteorites have similar compositions and petrographic features, independent of their enclosed objects. The FGRs are chemically homogeneous at the 10 m scale for major and minor elements and at the 25 m scale for trace elements. They display accretionary features and contain large amounts of volatiles, presumably water. They are depleted in Ca, Mn, and S but enriched in P. All FGRs show a slightly fractionated rare earth element (REE) pattern, with enrichments of Gd and Yb and depletion of Er. Gd is twice as abundant as Er. Our results indicate that those FGRs are not genetically related to their enclosed cores. They were sampled from a reservoir of homogeneously mixed dust, prior to accretion to their parent body. The rim materials subsequently experienced aqueous alteration under identical conditions. Based on their mineral, textural, and especially chemical similarities, we conclude that ALH 8 1002 and LEW 90500 likely have a similar or identical source.

  14. Strength and Microstructure of Ceramics

    DTIC Science & Technology

    1989-11-01

    processing defects (pores or inclusions), etc. Theoretically, flaws have been represented as scaled-down versions of large cracks, so that the...no spurious reflections. confirming that the defects were not microtwins, From the TEM evidence. alhing with corresponding observations of fault...Lawn Vol. 71. No. I Interfaces. can be viewred as high-energy planar defects . AS Such. V. Conclusions they represent favored sites for microcrack

  15. First Principles Based Simulation of Reaction-Induced Phase Transition in Hydrogen Storage and Other Materials

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

    Ge, Qingfeng

    2014-08-31

    This major part of this proposal is simulating hydrogen interactions in the complex metal hydrides. Over the period of DOE BES support, key achievements include (i) Predicted TiAl 3Hx as a precursor state for forming TiAl 3 through analyzing the Ti-doped NaAlH 4 and demonstrated its catalytic role for hydrogen release; (ii) Explored the possibility of forming similar complex structures with other 3d transition metals in NaAlH 4 as well as the impact of such complex structures on hydrogen release/uptake; (iii) Demonstrated the role of TiAl 3 in hydriding process; (iv) Predicted a new phase of NaAlH 4 that linksmore » to Na3AlH6 using first-principles metadynamics; (v) Examined support effect on hydrogen release from supported/encapsulated NaAlH 4; and (vi) Expanded research scope beyond hydrogen storage. The success of our research is documented by the peer-reviewed publications.« less

  16. Experimental Impacts into Chondritic Targets. Part 1; Disruption of an L6 Chondrite by Multiple Impacts

    NASA Technical Reports Server (NTRS)

    Cintala, Mark J.; Horz, Friedrich

    2007-01-01

    A fragment of an L6 chondrite (ALH 85017,13) with an initial mass (M(sub 0)) of 464.1 g was the target in a series of experimental impacts in which the largest remaining fragment (M(sub R)) after each shot was impacted by a 3.18-mm ceramic sphere at a nominal speed of 2 km/s. This continued until the mass of the largest remaining piece was less than half the mass of the target presented to that shot (M(sub S)). Two chunks of Bushveldt gabbro with similar initial masses were also impacted under the same conditions until M(sub R) was less than half M(sub 0). The two gabbro targets required a total of 1.51x10(exp 7) and 1.75x10(exp 7) erg/g to attain 0.27 and 0.33 M(sub R)/M(sub 0), respectively; the chondrite, however, was considerably tougher, reaching 0.40 and 0.21 M(sub R)/M(sub 0) only after receiving 2.37x10(exp 7) and 3.10x10(exp 7) erg g-1, respectively. The combined ejecta and spallation products from the gabbro impacts were coarser than those from the chondrite and in sufficient quantities that the new surface areas exceeded those from the meteorite until the fifth shot in the chondrite series, which was the number of impacts required to disrupt each gabbro target (i.e., MR/M0 = 0.5). Unlike the behavior shown in previous regolith-evolution series, neither gabbro target produced an enhancement in the size fraction reflecting the mean size of the crystals composing the rock (about 3 mm), an effect possibly related to the width of the shock pulse. The original chondrite was so fine-grained and fractured, and the variance in its grain-size distribution so large, that effects related to grain-size were relegated to the <63- m fraction. Impacts into ALH 85017 produced abundant, fine-grained debris, but otherwise the slopes of its size distributions were comparable to those from other experiments involving natural and fabricated terrestrial targets. The characteristic slopes of the chondrite's size distributions, however, were notably more constant over the entire

  17. Observation and Analysis of In Situ Carbonaceous Matter in Naklha. Part 2

    NASA Technical Reports Server (NTRS)

    Gibson, E. K., Jr.; Clemett, S. J.; Thomas-Kerpta, K. L.; McKay, D. S.; Wentworth, S. J.; Robert, F.; Verchovsky, A. B.; Wright, I. P.; Pillinger, C. T.; Rice, T.; hide

    2006-01-01

    The search for indigenous carbon components on Mars has been a challenge. The first attempt was the Viking GC-MS in situ experiment which gave inconclusive results at two sites on Mars [1]. After the discovery that the SNC meteorites were from Mars [2], [3-5] reported C isotopic compositional information which suggested a reduced C component present in the martian meteorites. [6 & 7] reported the presence of reduced C components (i.e., polycyclic aromatic hydrocarbons) associated with the carbonate globules in ALH84001. Jull et al. [8] noted in Nakhla there was an acid insoluble C component present with more than 75% of its C lacking any C-14, which is modern-day carbon. This C fraction was believed to be either indigenous martian or ancient meteoritic carbon. Fisk et al. [9, 10] have shown textural evidence along with C-enriched areas within fractures in Nakhla and ALH84001. To further understand the nature of possible indigenous reduced C components, we have carried out a variety of measurements on martian meteorites. For this presentation we will discuss only the Nakhla results. Interior samples from the Nakhla SNC meteorite, recently made available by the British Museum of Natural History, were analyzed. Petrographic examination [11, McKay et al., this volume] of Nakhla showed evidence of fractures (approx.0.5 micron wide) filled with dark brown to black dendritic material [Fig. 1] with characteristics similar to those observed by [10]. Iddingsite is also present along fractures in olivine. Fracture filling and dendritic material was examined by SEM-EDX, TEM-EDX, Focused Electron Beam microscopy, Laser Raman Spectroscopy, Nano-SIMS Ion Micro-probe, and Stepped-Combustion Static Mass Spectrometry.

  18. METEORITE - ASTRONOMY

    NASA Image and Video Library

    1985-08-28

    S85-39565 (For release August 1996) --- According to scientists, this 4.5 billion year old rock, labeled meteorite ALH84001, is believed to have once been a part of Mars and to contain fossil evidence that primitive life may have existed on Mars more than 3.6 billion years ago. The rock is a portion of a meteorite that was dislodged from Mars by a huge impact about 16 million years ago and that fell to Earth in Antarctica 13,000 years ago. The meteorite was found in Allan Hills ice field, Antarctica, by an annual expedition of the National Science Foundation?s Antarctic Meteorite Program in 1984. It is preserved for study at the Johnson Space Center?s (JSC) Meteorite Processing Laboratory in Houston, Texas.

  19. Angular distribution of γ rays from neutron-induced compound states of 140La

    NASA Astrophysics Data System (ADS)

    Okudaira, T.; Takada, S.; Hirota, K.; Kimura, A.; Kitaguchi, M.; Koga, J.; Nagamoto, K.; Nakao, T.; Okada, A.; Sakai, K.; Shimizu, H. M.; Yamamoto, T.; Yoshioka, T.

    2018-03-01

    The angular distribution of individual γ rays, emitted from a neutron-induced compound-nuclear state via radiative capture reaction of 139La(n ,γ ) has been studied as a function of incident neutron energy in the epithermal region by using germanium detectors. An asymmetry ALH was defined as (NL-NH) /(NL+NH) , where NL and NH are integrals of low- and high-energy region of a neutron resonance respectively, and we found that ALH has the angular dependence of (A cosθγ+B ) , where θγ is the emitted angle of γ rays, with A =-0.3881 ±0.0236 and B =-0.0747 ±0.0105 in 0.74 eV p -wave resonance. This angular distribution was analyzed within the framework of interference between s - and p -wave amplitudes in the entrance channel to the compound-nuclear state, and it is interpreted as the value of the partial p -wave neutron width corresponding to the total angular momentum of the incident neutron combined with the weak matrix element, in the context of the mechanism of enhanced parity-violating effects. Additionally, we use the result to quantify the possible enhancement of the breaking of time-reversal invariance in the vicinity of the p -wave resonance.

  20. Trace element distributions in primitive achondrites

    NASA Technical Reports Server (NTRS)

    Davis, Andrew M.; Prinz, Martin; Weisberg, Michael K.

    1993-01-01

    The primitive achondrites have approximately chondritic bulk chemical composition but achondritic textures. Clayton et al. show that nine of these meteorites, the acapulcoites and the lodranites, have similar oxygen isotopic compositions. The acapulcoites appear to be highly metamorphosed, but undifferentiated meteorites of chondritic composition; whereas, the lodranites appear to have lost a feldspathic partial melt. In order to learn more about metamorphic processes and partial melt removal, we have measured the trace element compositions of constituent phases of a number of primitive achondrites by ion microprobe. We have analyzed two acapulcoites, Acapulco and ALH81261 (paired with ALH77081), and three londranites, Lodran, LEW88280, and MAC88177. In addition, we analyzed LEW88663, which has the bulk composition, mineral chemistry, and oxygen isotopic composition of L-chondrites, but is metal-free and has an achondrite texture; and Divnoe, a plagioclase-poor, olivine-rich primitive achondrite with an oxygen isotopic composition similar to that of the group IAB iron meteorites. These meteorites show a variety of REE patterns in their constituent phases, and there are consistent differences between acapulcoites and lodranites that are consistent with removal of a LREE- and Eu-enriched melt that is apparently responsible for the low plagioclase content of lodranites.

  1. Synthesis of square-planar aluminum(III) complexes.

    PubMed

    Thompson, Emily J; Myers, Thomas W; Berben, Louise A

    2014-12-15

    The synthesis of two four-coordinate and square planar (SP) complexes of aluminum(III) is presented. Reaction of a phenyl-substituted bis(imino)pyridine ligand that is reduced by two electrons, Na2((Ph)I2P(2-)), with AlCl3 afforded five-coordinate [((Ph)I2P(2-))Al(THF)Cl] (1). Square-planar [((Ph)I2P(2-))AlCl] (2) was obtained by performing the same reaction in diethyl ether followed by lyphilization of 2 from benzene. The four-coordinate geometry index for 2, τ4, is 0.22, where 0 would be a perfectly square-planar molecule. The analogous aluminum hydride complex, [((Ph)I2P(2-))AlH] (3), is also square-planar, and was characterized crystallographically and has τ4=0.13. Both 2 and 3 are Lewis acidic and bind 2,6-lutidine. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. America’s Public Diplomacy Deficit

    DTIC Science & Technology

    1997-01-01

    experienced soldiers that the servrces so desperately need to keep Unfortunately, rt 1s clear that the objectives-resources unbalance will not be resolved...do we square the circle? The obvrous alternative 1s to work closely with our alhes, both to promote world economrc growth and share the security...and predictability in trade relations that led to raped expansion m trade and growth m economic prosperrty Increased trade in turn demanded expansion

  3. Computational Study of Formic Acid Dehydrogenation Catalyzed by Al(III)-Bis(imino)pyridine.

    PubMed

    Lu, Qian-Qian; Yu, Hai-Zhu; Fu, Yao

    2016-03-18

    The mechanism of formic acid dehydrogenation catalyzed by the bis(imino)pyridine-ligated aluminum hydride complex (PDI(2-))Al(THF)H (PDI=bis(imino)pyridine) was studied by density functional theory calculations. The overall transformation is composed of two stages: catalyst activation and the catalytic cycle. The catalyst activation begins with O-H bond cleavage of HCOOH promoted by aluminum-ligand cooperation, followed by HCOOH-assisted Al-H bond cleavage, and protonation of the imine carbon atom of the bis(imino)pyridine ligand. The resultant doubly protonated complex ((H,H) PDI)Al(OOCH)3 is the active catalyst for formic acid dehydrogenation. Given this, the catalytic cycle includes β-hydride elimination of ((H,H) PDI)Al(OOCH)3 to produce CO2, and the formed ((H,H) PDI)Al(OOCH)2 H mediates HCOOH to release H2. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Sodium-based hydrides for thermal energy applications

    NASA Astrophysics Data System (ADS)

    Sheppard, D. A.; Humphries, T. D.; Buckley, C. E.

    2016-04-01

    Concentrating solar-thermal power (CSP) with thermal energy storage (TES) represents an attractive alternative to conventional fossil fuels for base-load power generation. Sodium alanate (NaAlH4) is a well-known sodium-based complex metal hydride but, more recently, high-temperature sodium-based complex metal hydrides have been considered for TES. This review considers the current state of the art for NaH, NaMgH3- x F x , Na-based transition metal hydrides, NaBH4 and Na3AlH6 for TES and heat pumping applications. These metal hydrides have a number of advantages over other classes of heat storage materials such as high thermal energy storage capacity, low volume, relatively low cost and a wide range of operating temperatures (100 °C to more than 650 °C). Potential safety issues associated with the use of high-temperature sodium-based hydrides are also addressed.

  5. Effects of the supplementation with an high-polyphenols extra-virgin olive oil on kinetic sperm features and seminal plasma oxidative status in healthy dogs.

    PubMed

    Tufarelli, V; Rizzo, A; Lacalandra, G M; Guaricci, A C; Laudadio, V; Valentini, L

    2018-06-01

    The aim of this work was to evaluate the effects of the supplementation of two extra-virgin olive oils (EVOO) having different polyphenols content, on canine spermatozoa kinetic parameters and seminal plasma oxidative status. The study was conducted on 12 clinically healthy dogs of different breeds (2-7 years, 5-48 kg of body weight) divided into two groups: an experimental group supplemented with EVOO (Coratina cultivar) high in polyphenols (H-P) and a control group fed EVOO (Cima di Bitonto cultivar) low in polyphenols (L-P). The oil was daily administered per os (1 ml/3 kg BW) before meal. Semen collection was made twice at 15 days distance (D0 1 and D0 2 ) and then at 30 (D30), 60 (D60) and 90 (D90) days. Semen concentration and kinetic parameters were measured using computer-assisted sperm analysis (CASA) system to evaluate: sperm total count, sperm motile (MOT%), progressive motility (PROGR%) and its fractions, straight-line velocity (VSL, μm/s), curvilinear velocity (VCL, μm/s), average path velocity (VAP, μm/s), amplitude of lateral head displacement (ALH, μm), beat cross frequency (BCF, Hz), straightness (STR%) and linearity (LIN%). On seminal plasma, reactive oxygen species (ROS) and biological antioxidant potential (BAP) were tested. From findings, no differences were found for sperm MOT, VSL, VCL, VAP, ALH, BCF, STR, LIN and BAP. A gradual enhancement of PROGR% was observed in H-P group (p < .01). The ROS levels were higher in dogs H-P compared to the other group (p < .05). In conclusion, our results highlight the positive effects of EVOO polyphenols on sperm PROGR% in healthy dogs. © 2018 Blackwell Verlag GmbH.

  6. Seminal plasma removal by density-gradient centrifugation is superior for goat sperm preservation compared with classical sperm washing.

    PubMed

    Santiago-Moreno, J; Esteso, M C; Castaño, C; Toledano-Díaz, A; Delgadillo, J A; López-Sebastián, A

    2017-06-01

    Seminal plasma removal is routine in goat sperm cryopreservation protocols. The classical washing procedure designed to accomplish this usually leaves the pellet resulting from use of this procedure contaminated with dead sperm, debris, and cells other than sperm. This contamination negatively affects viability of sperm after cryopreservation. The present research was conducted to compare the effect on chilled and frozen-thawed goat sperm of the classical washing method to that of a selective washing method involving density gradient centrifugation (DGC). In the first experiment, sperm variables were measured in freshly collected sperm, and again after its washing with both methods and chilling at 5°C for 0, 3, 24, 48, 72 or 96h. The DGC-washed sperm had greater (P<0.01) straight line velocity (VSL), average path velocity (VAP) and progression ratio values at all chilling times. The amplitude of lateral head displacement (ALH) was, however, less (P<0.001) in the DGC-washed sperm at all chilling times. There was a negative correlation (P<0.05) between ALH and VSL. In the second experiment involving the freezing-thawing of sperm washed by using either method, aliquots were post-wash diluted with a Tris-citric acid/glucose/egg yolk/glycerol-based medium and frozen in liquid nitrogen for 5days. After thawing, neither the VCL, VSL nor VAP of the DGC-washed samples were affected, whereas the traditionally washed samples had less motility. In conclusion, the use of DGC was associated with enhanced sperm motility variables after chilling and freezing-thawing. This procedure would, therefore, be a useful means of removing seminal plasma from goat semen and obtaining greater quality sperm for insemination purposes. Copyright © 2017. Published by Elsevier B.V.

  7. Electron exchange between r-keggin tungstoaluminates and a well-defined cluster-anion probe for studies in electron transfer

    Treesearch

    Yurii V. Geletii; Craig L. Hill; Alan J. Bailey; Kenneth I. Hardcastle; Rajai H. Atalla; Ira A. Weinstock

    2005-01-01

    Fully oxidized [alpha]-AlIIIW12O405-(1ox), and one-electron-reduced [alpha]-AlIIIW12O406-(1red), are well-behaved (stable and free of ion pairing) over a wide range of pH and ionic-strength values at room temperature in water. Having established this, 27Al NMR spectroscopy is used to measure rates of electron exchange between 1ox (27Al NMR: 72.2 ppm relative to Al(H2O)...

  8. CM chondrites exhibit the complete petrologic range from type 2 to 1. [Abstract only

    NASA Technical Reports Server (NTRS)

    Zolensky, M. E.; Browning, L. B.

    1994-01-01

    Recognition and characterization of the different CM lithologies as components in all meteorites could reveal details of the nature and chronology of alteration and brecciation events on hydrous asteroids. The CM chondrites are of particular interest, as they are the most common carbonaceous chondrites and are found as clasts within other types of meteorites, which suggests that the CM parent asteroids are (or were) widespread in the sections of the asteroid belt providing samples to Earth. Some CM2s, including EET 90047, ALH 83100, and Y 82042, are more 'extensively' altered, and are distinguished by a high proportion of Mg-rich phyllosilicates and Ca-Mg carbonates, frequently in rounded aggregates, and near absence of olivine or pyroxene. 'Completely' altered CMs, called CM1s, essentially lack olivine or pyroxene; these include EET 83334, ALH 88045, and the CM1 clasts in Kaidun. Cold Bokkeveld and EET 84034, both highly brecciated CMs, consist of both extensively and completely altered lithologies. We describe how these lithologies further cosntrain physicochemical conditions on hydrous asteroids. We conclude that CM chondrites exhibit the petrologic range 2 through 1, and that progressive alteration on the parent hydrous asteroid(s) was accompanied by significant increases in temperature (to a peak of approximately 450 C), fO2, water-rock ratio, and (locally) degree of chemical leaching, all well beyond the conditions recorded by CM2s.

  9. Microbial Extremophiles in Evolutionary Aspect

    NASA Technical Reports Server (NTRS)

    Pikuta, Elena V.; Hoover, Richard B.

    2007-01-01

    The microflora of the cryosphere of planet Earth provides the best analogs for life forms that might be found in the permafrost or polar ice caps of Mars, near the surface of the cometary nuclei, or in the liquid water beneath the ice crusts of icy moons of Jupiter and Saturn. For astrobiology the focus on the study alkaliphilic microorganisms was enhanced by the findings of abundant carbonates and carbonate globules rimmed with possibly biogenic magnetites in association with the putative microfossils in the ALH84001 meteorite. Although the ALH84001 "nanofossils" were to small and simple to be unambiguously recognized as biogenic, they stimulated Astrobiology research and studies of microbial extremophiles and biomarkers in ancient rocks and meteorites. Recent studies of CI and CM carbonaceous meteorites have resulted in the detection of the well-preserved mineralized remains of coccoidal and" filamentous microorganisms in cyanobacterial mats. Energy Dispersive X-ray Analysis has shown anomalous biogenic element ratios clearly indicating they are not recent biological contaminants. This paper reviews microbial extremophiles in context of their significance to Astrobiology and the evolution of life. Extremophilic microorganisms on Earth are models for life that might endure high radiation environments in the ice near the surface of comets or on the icy moons of Jupiter and Saturn and in the seafloor deep beneath the icy crusts of Europa and Enceladus.

  10. [Spermicidal effect of alcohol extracts from different ratios of Sophora flavescens Ait/Chinese Bulbul in vitro].

    PubMed

    Meng, Xiang-hu; Lu, Can-feng; Zang, Guang-hui; Fan, Long-chang; Wang, Tao; Ding, Jing; Su, Qian; Yin, Chun-ping; Liu, Ji-hong

    2012-01-01

    To observe the spermicidal effect of alcohol extracts from different ratios of Sophora flavescens Ait/Chinese Bulbul in vitro. Semen samples aseptically obtained by masturbation and prepared by density gradient centrifugation from 15 healthy men were incubated in the alcohol extracts from 9 different ratios of Sophora flavescens Ait/Chinese Bulbul for 20 seconds, 2 minutes and 4 minutes. Then the motility and movement parameters of the sperm were detected by computer-assisted semen analysis, and the minimal effective concentrations of the instant spermicidal effect of the extracts were determined. At the ratio of 3:1, the extract at 0.5 mg/ml significantly inhibited the sperm motility and other sperm movement parameters VCL, VSL, VAP, ALH, WOB and MAD, as compared with the control group. The minimal effective concentration of the instant spermicidal effect of the extracts was 3.5 mg/ml at 3:1. The alcohol extracts from Sophora flavescens Ait and Chinese Bulbul at the ratio of 3:1 have the best spermicidal effect in vitro.

  11. What we have learned about Mars from SNC meteorites

    NASA Technical Reports Server (NTRS)

    Mcsween, Harry Y., Jr.

    1994-01-01

    lithosphere, but it is in isotopic equilibrium with the atmosphere and has been since 1.3 Ga. The isotopically heavy atmosphere/hydrosphere composition deduced from these rocks reflects a loss process more severe than current atmospheric evolution models, and the occurence of carbonates in SNC meteorites suggest that they, rather than scapolite or hydrous carbonates, are the major crustal sink for CO2. Weathering products in SNC meteorites support the idea of limited alteration of the lithosphere by small volumes of saline, CO2-bearing water. Atmospheric composition and evolution are further constrained by noble gases in these meteorites, although Xe and Kr isotopes suggest different origins for the atmosphere. Planetary ejection of these rocks has promoted an advance in the understanding of impact physics, which has been accomplished by a model involving spallation during large cratering events. Ejection of all the SNC meteorites (except ALH84001) in one or two events may provide a plausible solution to most constraints imposed by chronology, geochemistry, and cosmic ray exposure, although problems remain with this scenario; ALH84001 may represent older martian crust sampled during a separate impact.

  12. Approaches to Establishing the Chemical Structure of Extraterrestrial Organic Solids

    NASA Technical Reports Server (NTRS)

    Cody, G. D.; Alexander, C. M. OD.; Wirick, Susan

    2003-01-01

    The majority of extraterrestrial organic matter in carbonaceous chondrites resides in a chemically complex, insoluble and perhaps macromolecular phase. We have been applying a series of independent solid state NMR experiments that are designed to provide a self consistent chemical characterization of this complex material. To date we have thoroughly analyzed 8 organic residues from different meteorites, including a CR2 (EET92042), CIl(Orgueil), CM2 (Murchison), Tagish Lake, CM2 (AlH83100), CM2 (Cold Bokkefeld), CM2 (Mighei), CM3 (Y86720). In fig 1. (1)H to (13)C cross polarization NMR spectra of four of these are shown. Note that there exists an enormous range in chemistry exhibited in organic solid [evident by the breadth of the spectral features both in the aliphatic region (sp(sup 3)) and the aromatic region (sp(sup 2))]. There is also considerable differences in the carbon chemistry across the meteorite groups.

  13. Militarism and Foreign Conflict Behavior: A Quantitative Study Revisited.

    DTIC Science & Technology

    1982-05-20

    more, or other, indicators could have been dhosen it was felt that than seven were universally aplicable and describe the overall militarized...discussion of each indicator will point out where it varies from the 1972 study, if aplicable . I~f R tmtram an A ~~tg of _ErGtOD& ren for B9alh and...Demonstrations 7 8 Troop Movements 8 5 Severance of Diplomatic Relations 9 9 Military Actions 10 10 Mobilization 11 11 War 12 12 *For a complete description of

  14. An alternative hypothesis for high-T 40Ar/39Ar age spectrum discordance in polyphase extraterrestrial materials

    NASA Astrophysics Data System (ADS)

    Cassata, W. S.; Shuster, D. L.; Renne, P. R.; Weiss, B. P.

    2009-12-01

    A common feature observed in 40Ar/39Ar age spectra of extraterrestrial (ET) rocks is a conspicuous decrease in the ages of high temperature extractions relative to lower temperature steps and a correlated increase in Ca/K, often succeeded by a monotonic increase in ages. This feature is routinely attributed to recoil-implanted 39Ar from a potassium (K)-rich donor phase into a K-poor receptor phase (e.g., 1,2). While 39Ar recoil redistribution is undoubtedly manifested in many terrestrial and ET 40Ar/39Ar whole-rock age spectra, it cannot easily explain the magnitude of high release temperature 40Ar*/39ArK anomalies observed in Martian meteorites ALH 84001 and Nakhla, as well as other course-grained meteorites and lunar rocks. Depending on the aliquot and sample, 50 - 100% of the pyroxene release spectra in ALH 84001 and Nakhla appear strongly perturbed to lower ages. As the mean recoil distance of 39Ar ~0.1 µm, the recoil hypothesis demands that a high-K phase be ubiquitously distributed amongst sub-micron to micron sized pyroxene crystals to account for the observed pyroxene age spectra. However, in both Nakhla and ALH 84001, pyroxene is often completely isolated from high-K phases and individual grains commonly exceed 100 µm in diameter. 40Ar/39Ar analyses of pyroxene-bearing terrestrial basalts, wherein fine-grained pyroxene and plagioclase are intimately adjoined, show that recoil-implanted 39Ar into pyroxene produces much less precipitous anomalies in 40Ar*/39ArK, as predicted by the recoil lengthscale. An alternative hypothesis is that whole-rock age spectra of ET samples with anomalously low ages at high temperatures may reflect diffusive 40Ar distributions within considerably degassed pyroxene grains. Owing to apparent differences in activation energies between glass and/or plagioclase and pyroxene, 40Ar may diffuse more rapidly from pyroxene under certain high-temperature conditions (i.e., above the temperature at which the extrapolated Ar Arrhenius

  15. Evolution of the martian mantle as recorded by igneous rocks

    NASA Astrophysics Data System (ADS)

    Balta, J. B.; McSween, H. Y.

    2013-12-01

    Martian igneous rocks provide our best window into the current state of the martian mantle and its evolution after accretion and differentiation. Currently, those rocks have been examined in situ by rovers, characterized in general from orbiting spacecraft, and analyzed in terrestrial laboratories when found as meteorites. However, these data have the potential to bias our understanding of martian magmatism, as most of the available meteorites and rover-analyzed rocks come from the Amazonian (<2 Ga) and Hesperian (~3.65 Ga) periods respectively, while igneous rocks from the Noachian (>3.8 Ga) have only been examined by orbiters and as the unique meteorite ALH 84001. After initial differentiation, the main planetary-scale changes in the structure of Mars which impact igneous compositions are cooling of the planet and thickening of the crust with time. As the shergottite meteorites give ages <500 Ma1, they might be expected to represent thick-crust, recent volcanism. Using spacecraft measurements of volcanic compositions and whole rock compositions of meteorites, we demonstrate that the shergottite meteorites do not match the composition of the igneous rocks composing the young volcanoes on Mars, particularly in their silica content, and no crystallization or crustal contamination trend reproduces the volcanoes from a shergottite-like parent magma. However, we show that the shergottite magmas do resemble older martian rocks in composition and mineralogy. The Noachian-aged meteorite ALH 84001 has similar radiogenic-element signatures to the shergottites and may derive from a similar mantle source despite the age difference2. Thus, shergottite-like magmas may represent melting of mantle sources that were much more abundant early in martian history. We propose that the shergottites represent the melting products of an originally-hydrous martian mantle, containing at least several hundred ppm H2O. Dissolved water can increase the silica content of magmas and thus

  16. Effects of diluting medium and holding time on sperm motility analysis by CASA in ram.

    PubMed

    Mostafapor, Somayeh; Farrokhi Ardebili, Farhad

    2014-01-01

    The aim of this study was to evaluate the effects of dilution rate and holding time on various motility parameters using computer-assisted sperm analysis (CASA). The semen samples were collected from three Ghezel rams. Samples were diluted in seminal plasma (SP), phosphate-buffered saline (PBS) containing 1% bovine serum albumin (BSA) and Bioexcell. The motility parameters that computed and recorded by CASA include curvilinear velocity (VCL), straight line velocity (VSL), average path velocity (VAP), straightness (STR), linearity (LIN), amplitude of lateral head displacement (ALH), and beat cross frequency (BCF). In all diluters, there was a decrease in the average of all three parameters of sperms movement velocity as the time passed, but density of this decrease was more intensive in SP. The average of ALH between diluters indicated a significant difference, as it was more in Bioexcell in comparison with the similar amount in SP and PBS. The average of LIN in the diluted sperms in Bioexcell was less than two other diluters in all three times. The motility parameters of the diluted sperms in Bioexcell and PBS indicated an important and considerable difference with the diluted sperms in SP. According to the gained results, the Bioexcell has greater ability in preserving motility of sperm in comparison with the other diluters but as SP is considered as physiological environment for sperm. It seems that the evaluation of the motility parameters in Bioexcell and PBS cannot be an accurate and comparable evaluation with SP.

  17. Papillary lesions of the breast: To excise or observe?

    PubMed

    Khan, Sidrah; Diaz, Adrian; Archer, Kellie J; Lehman, Rebecca R; Mullins, Tiffany; Cardenosa, Gilda; Bear, Harry D

    2018-05-01

    Papillary lesions of the breast range from benign to atypical to malignant. Although papillomas without frank cancer are benign, their management remains controversial. When a core needle biopsy of a lesion yields a diagnosis of intraductal papilloma with atypia, excision is generally recommended to rule out a concurrent malignant neoplasm. For intraductal papillomas without atypia, however, recommendations for excision versus observation are variable. The aims of this study are to evaluate the rate of concurrent malignancies for intraductal papilloma diagnosed on core needle biopsy and to assess the long-term risk of developing cancer after the diagnosis of a papillary lesion. This single institution retrospective study analyzed 259 patients that were diagnosed with intraductal papilloma (IDP) by core needle biopsy from 1995 to 2010. Patients were grouped by initial diagnosis into three groups (papilloma without atypia, papilloma with atypia, and papilloma with atypical duct hyperplasia or atypical lobular hyperplasia (ADH/ALH) and followed up for long-term outcomes. After a core needle biopsy showing IDP with atypia or IDP + ADH/ALH, surgical excision yielded a diagnosis of concomitant invasive or ductal in situ cancer in greater that 30% of cases. For intraductal papilloma without atypia, the likelihood of cancer was much lower. Moreover, even with excision, the finding of intraductal papilloma with atypia carries a significant risk of developing cancer long-term, and such patients should be followed carefully and perhaps should be considered for chemoprevention. © 2017 Wiley Periodicals, Inc.

  18. Prototype electrostatic ground state approach to predicting crystal structures of ionic compounds: Application to hydrogen storage materials

    NASA Astrophysics Data System (ADS)

    Majzoub, E. H.; Ozoliņš, V.

    2008-03-01

    We have developed a procedure for crystal structure generation and prediction for ionic compounds consisting of a collection of cations and rigid complex anions. Our approach is based on global optimization of an energy functional consisting of the electrostatic and soft-sphere repulsive energies using Metropolis Monte Carlo (MMC) simulated annealing in conjunction with smoothing of the potential energy landscape via the distance scaling method. The resulting structures, or prototype electrostatic ground states (PEGS), are subsequently relaxed using first-principles density-functional theory (DFT) calculations to obtain accurate structural parameters and thermodynamic properties. This method is shown to produce the ground state structures of NaAlH4 and Mg(AlH4)2 , as well as the mixed cation alanate K2LiAlH6 . For LiAlH4 , the PEGS search produces a structure with a static DFT total energy equal to that of the experimentally observed structure; the latter is stabilized by vibrational contributions to the free energy. For mixed-valence hexa-alanates, XY AlH6 , where X=(Li,Na,K) , and Y=(Mg,Ca) , the PEGS method predicts six unsuspected structure types, which are not found in the existing structure databases. The PEGS search yields energies that are, on the average, better than the best database structures with the same number of atoms per unit cell, demonstrating the predictive power and usefulness of the PEGS structures. In addition to the recently synthesized LiMgAlH6 compound, we predict that LiCaAlH6 , NaCaAlH6 , and KCaAlH6 are also thermodynamically stable with respect to phase separation into other alanates and metal hydrides. In contrast, NaMgAlH6 and KMgAlH6 are slightly unstable (by less than 3kJ/mol ) relative to the phase separation into NaAlH4 , KAlH4 , and MgH2 . We suggest that solid-state ion-exchange reactions between X3AlH6 (X=Li,Na,K) and YCl2 (Y=Mg,Ca) could be used to synthesize the predicted mixed-valence hexa-alanates.

  19. The Future of Human Exploration

    NASA Technical Reports Server (NTRS)

    Cooke, Doug

    2001-01-01

    This slide presentation reviews the near term future of human space exploration in terms of possible mission scenarios, propulsion technologies, orbital dynamics that lead to Low-Energy Transfer from Earth-Moon LI to Solar Libration Points and Return Potential Staging Point for Human Mars Missions. It also examines the required evolution of mission architecture, solar electric propulsion concept, vehicle concepts for future Mars missions, and an overview of a Mars Mission, Also in this presentation are pictures of several historic personages and occasions, and a view of a Mars Meteorite (i.e., ALH84001.0)

  20. A Perspective on the Numerical and Experimental Characteristics of Multi-Mode Dry-Friction Whip and Whirl

    DTIC Science & Technology

    2008-06-01

    different builds of the ALH; only the first of these ran according to plan . Following test 1, the development of large supersynchronous vibrations...Precession Frequency vs. Speed Case:20, Prox:1, Dn 0 50 100 150 200 250 0 50 100 150 200 Speed (rpm) A m pl itu de ( μ m ) Max Backward Precession...1 -2000 -1500 -1000 -500 0 500 1000 1500 2000 0 50 100 150 200 250 0 50 100 150 Waterfall Plot Frequency (Hz) Speed (rpm) A m pl itu de ( μ m

  1. Reversible hydrogen storage by NaAlH4 confined within a titanium-functionalized MOF-74(Mg) nanoreactor.

    PubMed

    Stavila, Vitalie; Bhakta, Raghunandan K; Alam, Todd M; Majzoub, Eric H; Allendorf, Mark D

    2012-11-27

    We demonstrate that NaAlH(4) confined within the nanopores of a titanium-functionalized metal-organic framework (MOF) template MOF-74(Mg) can reversibly store hydrogen with minimal loss of capacity. Hydride-infiltrated samples were synthesized by melt infiltration, achieving loadings up to 21 wt %. MOF-74(Mg) possesses one-dimensional, 12 Å channels lined with Mg atoms having open coordination sites, which can serve as sites for Ti catalyst stabilization. MOF-74(Mg) is stable under repeated hydrogen desorption and hydride regeneration cycles, allowing it to serve as a "nanoreactor". Confining NaAlH(4) within these pores alters the decomposition pathway by eliminating the stable intermediate Na(3)AlH(6) phase observed during bulk decomposition and proceeding directly to NaH, Al, and H(2), in agreement with theory. The onset of hydrogen desorption for both Ti-doped and undoped nano-NaAlH(4)@MOF-74(Mg) is ∼50 °C, nearly 100 °C lower than bulk NaAlH(4). However, the presence of titanium is not necessary for this increase in desorption kinetics but enables rehydriding to be almost fully reversible. Isothermal kinetic studies indicate that the activation energy for H(2) desorption is reduced from 79.5 kJ mol(-1) in bulk Ti-doped NaAlH(4) to 57.4 kJ mol(-1) for nanoconfined NaAlH(4). The structural properties of nano-NaAlH(4)@MOF-74(Mg) were probed using (23)Na and (27)Al solid-state MAS NMR, which indicates that the hydride is not decomposed during infiltration and that Al is present as tetrahedral AlH(4)(-) anions prior to desorption and as Al metal after desorption. Because of the highly ordered MOF structure and monodisperse pore dimensions, our results allow key template features to be identified to ensure reversible, low-temperature hydrogen storage.

  2. Nature of Reduced Carbon in Martian Meteorites

    NASA Technical Reports Server (NTRS)

    Gibson, Everett K., Jr.; McKay, D. S.; Thomas-Keprta, K. L.; Clemett, S. J.; White, L. M.

    2012-01-01

    Martian meteorites provide important information on the nature of reduced carbon components present on Mars throughout its history. The first in situ analyses for carbon on the surface of Mars by the Viking landers yielded disappointing results. With the recognition of Martian meteorites on Earth, investigations have shown carbon-bearing phases exist on Mars. Studies have yielded presence of reduced carbon, carbonates and inferred graphitic carbon phases. Samples ranging in age from the first approximately 4 Ga of Mars history [e.g. ALH84001] to nakhlites with a crystallization age of 1.3 Ga [e.g. Nakhla] with aqueous alteration processes occurring 0.5-0.7 Ga after crystallizaton. Shergottites demonstrate formation ages around 165-500 Ma with younger aqueous alterations events. Only a limited number of the Martian meteorites do not show evidence of significance terrestrial alterations. Selected areas within ALH84001, Nakhla, Yamato 000593 and possibly Tissint are suitable for study of their indigenous reduced carbon bearing phases. Nakhla possesses discrete, well-defined carbonaceous phases present within iddingsite alteration zones. Based upon both isotopic measurements and analysis of Nakhla's organic phases the presence of pre-terrestrial organics is now recognized. The reduced carbon-bearing phases appear to have been deposited during preterrestrial aqueous alteration events that produced clays. In addition, the microcrystalline layers of Nakhla's iddingsite have discrete units of salt crystals suggestive of evaporation processes. While we can only speculate on the origin of these unique carbonaceous structures, we note that the significance of such observations is that it may allow us to understand the role of Martian carbon as seen in the Martian meteorites with obvious implications for astrobiology and the pre-biotic evolution of Mars. In any case, our observations strongly suggest that reduced organic carbon exists as micrometer- size, discrete structures

  3. Dehydrogenation kinetics and reversibility of LiAlH4-LiBH4 doped with Ti-based additives and MWCNT

    NASA Astrophysics Data System (ADS)

    Thaweelap, Natthaporn; Utke, Rapee

    2016-11-01

    Dehydrogenation kinetics and reversibility of LiAlH4-LiBH4 doped with Ti-based additives (TiCl3 and Ti-isopropoxide), multiwall carbon nanotubes (MWCNT), and MWCNT impregnated with Ti-based additives are proposed. Reduction of dehydrogenation temperature as well as improvements of kinetics and reversibility, especially decomposition of thermodynamically stable hydride (LiBH4) is obtained from the samples doped with Ti-isopropoxide and MWCNT. This can be due to the fact that the formations of LixAl(1-x)B2 and LiH-Al containing phase during dehydrogenation favor decomposition of LiH, leading to increment of hydrogen capacity, and stabilization of boron in solid state, resulting in improvement of reversibility. Besides, the curvatures and thermal conductivity of MWCNT benefit hydrogen diffusion and heat transfer during de/rehydrogenation. Nevertheless, deficient hydrogen content reversible is observed in all samples due to the irreversible of LiAlH4 and/or Li3AlH6 as well as the formation of stable phase (Li2B12H12) during de/rehydrogenation.

  4. Science verification of operational aerosol and cloud products for TROPOMI on Sentinel-5 precursor

    NASA Astrophysics Data System (ADS)

    Lelli, Luca; Gimeno-Garcia, Sebastian; Sanders, Abram; Sneep, Maarten; Rozanov, Vladimir V.; Kokhanvosky, Alexander A.; Loyola, Diego; Burrows, John P.

    2016-04-01

    With the approaching launch of the Sentinel-5 precursor (S-5P) satellite, scheduled by mid 2016, one preparatory task of the L2 working group (composed by the Institute of Environmental Physics IUP Bremen, the Royal Netherlands Meteorological Institute KNMI De Bilt, and the German Aerospace Center DLR Oberpfaffenhofen) has been the assessment of biases among aerosol and cloud products, that are going to be inferred by the respective algorithms from measurements of the platform's payload TROPOspheric Monitoring Instrument (TROPOMI). The instrument will measure terrestrial radiance with varying moderate spectral resolutions from the ultraviolet throughout the shortwave infrared. Specifically, all the operational and verification algorithms involved in this comparison exploit the sensitivity of molecular oxygen absorption (the A-band, 755-775 nm, with a resolution of 0.54 nm) to changes in optical and geometrical parameters of tropospheric scattering layers. Therefore, aerosol layer height (ALH) and thickness (AOT), cloud top height (CTH), thickness (COT) and albedo (CA) are the targeted properties. First, the verification of these properties has been accomplished upon synchronisation of the respective forward radiative transfer models for a variety of atmospheric scenarios. Then, biases against independent techniques have been evaluated with real measurements of selected GOME-2 orbits. Global seasonal bias assessment has been carried out for CTH, CA and COT, whereas the verification of ALH and AOT is based on the analysis of the ash plume emitted by the icelandic volcanic eruption Eyjafjallajökull in May 2010 and selected dust scenes off the Saharan west coast sensed by SCIAMACHY in year 2009.

  5. Design tool for estimating chemical hydrogen storage system characteristics for light-duty fuel cell vehicles

    DOE PAGES

    Brooks, Kriston P.; Sprik, Samuel J.; Tamburello, David A.; ...

    2018-04-07

    The U.S. Department of Energy (DOE) developed a vehicle Framework model to simulate fuel cell-based light-duty vehicle operation for various hydrogen storage systems. This transient model simulates the performance of the storage system, fuel cell, and vehicle for comparison to Technical Targets established by DOE for four drive cycles/profiles. Chemical hydrogen storage models have been developed for the Framework for both exothermic and endothermic materials. Despite the utility of such models, they require that material researchers input system design specifications that cannot be estimated easily. To address this challenge, a design tool has been developed that allows researchers to directlymore » enter kinetic and thermodynamic chemical hydrogen storage material properties into a simple sizing module that then estimates system parameters required to run the storage system model. Additionally, the design tool can be used as a standalone executable file to estimate the storage system mass and volume outside of the Framework model. Here, these models will be explained and exercised with the representative hydrogen storage materials exothermic ammonia borane (NH 3BH 3) and endothermic alane (AlH 3).« less

  6. Design tool for estimating chemical hydrogen storage system characteristics for light-duty fuel cell vehicles

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

    Brooks, Kriston P.; Sprik, Samuel J.; Tamburello, David A.

    The U.S. Department of Energy (DOE) developed a vehicle Framework model to simulate fuel cell-based light-duty vehicle operation for various hydrogen storage systems. This transient model simulates the performance of the storage system, fuel cell, and vehicle for comparison to Technical Targets established by DOE for four drive cycles/profiles. Chemical hydrogen storage models have been developed for the Framework for both exothermic and endothermic materials. Despite the utility of such models, they require that material researchers input system design specifications that cannot be estimated easily. To address this challenge, a design tool has been developed that allows researchers to directlymore » enter kinetic and thermodynamic chemical hydrogen storage material properties into a simple sizing module that then estimates system parameters required to run the storage system model. Additionally, the design tool can be used as a standalone executable file to estimate the storage system mass and volume outside of the Framework model. Here, these models will be explained and exercised with the representative hydrogen storage materials exothermic ammonia borane (NH 3BH 3) and endothermic alane (AlH 3).« less

  7. Pavement Functional Condition Indicators

    DTIC Science & Technology

    1975-02-01

    HiuhSiwed Rnod ffiillh’ hquiimml h’vulu- uimii. Keseareh Report No 7,vi (Center for Highway Keseareh, I he I niversiiN ol lesas at Austin. 1%K). "• Ko ^er S...III Scull AFB. Illim.is i?) Ko >al At-’ Wi«)dlifut(jf, 1-Jif>laral 111 Kiiiiliduc Al-H. Mk-liijjan (4) Zijvibnwkfii AH. limuam IS) Miiioi AKB, Norlh...K.J. IVters. Surltur hruiimi Slmly iif \\II nmi Hinhuury HKK-TI (Hifilm.iy Research Board. 147.1). "’I /uhi .oiil I. Sko «. A SIIKIV HI ihf

  8. Optimizing the multicycle subrotational internal cooling of diatomic molecules

    NASA Astrophysics Data System (ADS)

    Aroch, A.; Kallush, S.; Kosloff, R.

    2018-05-01

    Subrotational cooling of the AlH+ ion to the miliKelvin regime, using optimally shaped pulses, is computed. The coherent electromagnetic fields induce purity-conserved transformations and do not change the sample temperature. A decrease in a sample temperature, manifested by an increase of purity, is achieved by the complementary uncontrolled spontaneous emission which changes the entropy of the system. We employ optimal control theory to find a pulse that stirs the system into a population configuration that will result in cooling, upon multicycle excitation-emission steps. The obtained optimal transformation was shown capable to cool molecular ions to the subkelvins regime.

  9. Estimation of Inertial Parameters of Rigid Body Links of Manipulators.

    DTIC Science & Technology

    1986-02-01

    H AN ET RL. FED 86 UNCLRSSIFIED Al-H-88? NSSI4-8- C -O5OS F/ O 13/13 ML mmmmmmmmuhmhEMENOMONEE 1248 = . I 2.2. 36I W 11111 1.0 112.0 ~ Lm 11111 1111 25l...good match was obtained between joint [lror uesq’pre;Act om the estimated parameters and the joint torques computed A" rn fu~ S. C b.. .:. Massachusetts...value o , which if not zero indicates that linear combination of parameters, vYO, is identifiable. Since K is a function only of the geometry of the

  10. Modeling Chemical and Isotopic Variations in Lab Formed Hydrothermal Carbonates

    NASA Technical Reports Server (NTRS)

    Niles, P. B.; Leshin, L. A.; Golden, D. C.; Socki, R. A.; Guan, Y.; Ming, D. W.

    2005-01-01

    Chemical and mineralogical data (e.g. [1]) from Mars suggest that the history of liquid water on the planet was more sporadic in nature than long-lived. The non-equilibrium chemical and isotopic compositions of the carbonates preserved in the martian meteorite ALH84001 are direct evidence of ancient secondary minerals that have not undergone significant diagenesis or stabilization processes typical of long-lived aqueous systems on Earth. Thus secondary minerals and sediments on Mars may primarily record the characteristics of the aqueous environment in which they formed without being significantly overprinted by subsequent diagenetic processes during burial.

  11. Analysis and Thermodynamic Prediction of Hydrogen Solution in Solid and Liquid Multicomponent Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    Anyalebechi, P. N.

    Reported experimentally determined values of hydrogen solubility in liquid and solid Al-H and Al-H-X (where X = Cu, Si, Zn, Mg, Li, Fe or Ti) systems have been critically reviewed and analyzed in terms of Wagner's interaction parameter. An attempt has been made to use Wagner's interaction parameter and statistic linear regression models derived from reported hydrogen solubility limits for binary aluminum alloys to predict the hydrogen solubility limits in liquid and solid (commercial) multicomponent aluminum alloys. Reasons for the observed poor agreement between the predicted and experimentally determined hydrogen solubility limits are discussed.

  12. Structural Characterization of Metal Hydrides for Energy Applications

    NASA Astrophysics Data System (ADS)

    George, Lyci

    Hydrogen can be an unlimited source of clean energy for future because of its very high energy density compared to the conventional fuels like gasoline. An efficient and safer way of storing hydrogen is in metals and alloys as hydrides. Light metal hydrides, alanates and borohydrides have very good hydrogen storage capacity, but high operation temperatures hinder their application. Improvement of thermodynamic properties of these hydrides is important for their commercial use as a source of energy. Application of pressure on materials can have influence on their properties favoring hydrogen storage. Hydrogen desorption in many complex hydrides occurs above the transition temperature. Therefore, it is important to study the physical properties of the hydride compounds at ambient and high pressure and/or high temperature conditions, which can assist in the design of suitable storage materials with desired thermodynamic properties. The high pressure-temperature phase diagram, thermal expansion and compressibility have only been evaluated for a limited number of hydrides so far. This situation serves as a main motivation for studying such properties of a number of technologically important hydrides. Focus of this dissertation was on X-ray diffraction and Raman spectroscopy studies of Mg2FeH6, Ca(BH4) 2, Mg(BH4)2, NaBH4, NaAlH4, LiAlH4, LiNH2BH3 and mixture of MgH 2 with AlH3 or Si, at different conditions of pressure and temperature, to obtain their bulk modulus and thermal expansion coefficient. These data are potential source of information regarding inter-atomic forces and also serve as a basis for developing theoretical models. Some high pressure phases were identified for the complex hydrides in this study which may have better hydrogen storage properties than the ambient phase. The results showed that the highly compressible B-H or Al-H bonds and the associated bond disordering under pressure is responsible for phase transitions observed in brorohydrides or

  13. Do photoperiod and endocrine disruptor 4-tert-octylphenol effect on spermatozoa of bank vole (Clethrionomys glareolus)?

    PubMed

    Kotula-Balak, Malgorzata; Grzmil, Pawel; Chojnacka, Katarzyna; Andryka, Katarzyna; Bilinska, Barbara

    2014-05-15

    Photoperiod is an environmental signal that controls physiology and behavior of all organisms. Bank voles, which are seasonal breeders, are stimulated to reproduce by the long photoperiod associated with spring and summer. To date, physiology of bank vole spermatozoa has not been explored, although they constitute an interesting model for examining the relationship between photoperiod and xenoestrogen on spermatozoa function. In an attempt to evaluate the acute effect of 4-tert-octylphenol (OP) an in vitro system was used. Spermatozoa isolated from the cauda epididymidies of long-day (LD; 18 h light: 6 h darkness) and short-day (SD; 6 h light: 18 h darkness) bank voles were treated with two OP concentrations (10(-4) M and 10(-8)M, respectively). OP-treated spermatozoa were used for the examination of motility parameters (computer-assisted semen analyzer CEROS), acrosome integrity (Commassie blue staining), cAMP production (immunoenzymatic assay) and cell viability (flow-cytometry analysis). The study revealed the photoperiod-dependent effect of short OP-treatment on motility parameters of vole spermatozoa. In LD spermatozoa, an increase of velocities: (curvilinear velocity [VCL], average path velocity [VAP] straight line velocity [VSL]) and head activity (amplitude of the lateral head displacement, [ALH]) was found. Interestingly, in SD spermatozoa opposite effect on VCL, VAP, VSL and ALH was observed, however only after treatment with 10(-4)M OP. The dose-dependent influence of OP upon acrosome integrity, as well as cAMP levels, in relation to the reproductive status of voles was observed. Moreover, OP exposure affected spermatozoa morphology rather than spermatozoa viability. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. New Meteorite Type NWA 8159 Augite Basalt: Specimen from a Previously Unsampled Location on Mars?

    NASA Technical Reports Server (NTRS)

    Agee, C. B.; Muttik, N.; Ziegler, K.; Walton, E. L.; Herd, C. D. K.; McCubbin, F. M.; Santos, A. R.; Simon, J. I.; Peters, T. J.; Tappa, M. J.; hide

    2014-01-01

    Up until recently the orthopyroxenite ALH 84001, a singleton martian meteorite type, was the only sample that did not fit within the common SNC types. However with the discovery of the unique basaltic breccia NWA 7034 pairing group [1] the diversity of martian meteorites beyond SNC types was expanded, and now with Northwest Africa (NWA) 8159, and its possible pairing NWA 7635 [2], the diversiy is expanded further with a third unique non-SNC meteorite type. The existence of meteorite types beyond the narrow range seen in SNCs is what might be expected from a random cratering sampling of a geologically long-lived and complex planet such as Mars.

  15. Explicit and Observation-based Aerosol Treatment in Tropospheric NO2 Retrieval over China from the Ozone Monitoring Instrument

    NASA Astrophysics Data System (ADS)

    Liu, M.; Lin, J.; Boersma, F.; Pinardi, G.; Wang, Y.; Chimot, J.; Wagner, T.; Xie, P.; Eskes, H.; Van Roozendael, M.; Hendrick, F.

    2017-12-01

    Satellite retrieval of vertical column densities (VCDs) of tropospheric nitrogen dioxide (NO2) is influenced by aerosols substantially. Aerosols affect the retrieval of "effective cloud fraction (CF)" and "effective cloud top pressure (CP)" that are used in the subsequent NO2 retrieval to account for the presentence of clouds. And aerosol properties and vertical distributions directly affect the NO2 air mass factor (AMF) calculations. Our published POMINO algorithm uses a parallelized LIDORT-driven AMFv6 code to derive CF, CP and NO2 VCD. Daily information on aerosol optical properties are taken from GEOS-Chem simulations, with aerosol optical depth (AOD) further constrained by monthly MODIS AOD. However, the published algorithm does not include an observation-based constraint of aerosol vertical distribution. Here we construct a monthly climatological observation dataset of aerosol extinction profiles, based on Level-2 CALIOP data over 2007-2015, to further constrain aerosol vertical distributions. GEOS-Chem captures the temporal variations of CALIOP aerosol layer heights (ALH) but has an overall underestimate by about 0.3 km. It tends to overestimate the aerosol extinction by 10% below 2 km but with an underestimate by 30% above 2 km, leading to a low bias by 10-30% in the retrieved tropospheric NO2 VCD. After adjusting GEOS-Chem aerosol extinction profiles by the CALIOP monthly ALH climatology, the retrieved NO2 VCDs increase by 4-16% over China on a monthly basis in 2012. The improved NO2 VCDs are better correlated to independent MAX-DOAS observations at three sites than POMINO and DOMINO are - especially for the polluted cases, R2 reaches 0.76 for the adjusted POMINO, much higher than that for the published POMINO (0.68) and DOMINO (0.38). The newly retrieved CP increases by 60 hPa on average, because of a stronger aerosol screening effect. Compared to the CF used in DOMINO, which implicitly includes aerosol information, our improved CF is much lower and can

  16. Theoretical study of hydrogen storage in metal hydrides.

    PubMed

    Oliveira, Alyson C M; Pavão, A C

    2018-05-04

    Adsorption, absorption and desorption energies and other properties of hydrogen storage in palladium and in the metal hydrides AlH 3 , MgH 2 , Mg(BH 4 ) 2 , Mg(BH 4 )(NH 2 ) and LiNH 2 were analyzed. The DFT calculations on cluster models show that, at a low concentration, the hydrogen atom remains adsorbed in a stable state near the palladium surface. By increasing the hydrogen concentration, the tetrahedral and the octahedral sites are sequentially occupied. In the α phase the tetrahedral site releases hydrogen more easily than at the octahedral sites, but the opposite occurs in the β phase. Among the hydrides, Mg(BH 4 ) 2 shows the highest values for both absorption and desorption energies. The absorption energy of LiNH 2 is higher than that of the palladium, but its desorption energy is too high, a recurrent problem of the materials that have been considered for hydrogen storage. The release of hydrogen, however, can be favored by using transition metals in the material structure, as demonstrated here by doping MgH 2 with 3d and 4d-transition metals to reduce the hydrogen atomic charge and the desorption energy.

  17. Detection of oxygen isotopic anomaly in terrestrial atmospheric carbonates and its implications to Mars.

    PubMed

    Shaheen, R; Abramian, A; Horn, J; Dominguez, G; Sullivan, R; Thiemens, Mark H

    2010-11-23

    The debate of life on Mars centers around the source of the globular, micrometer-sized mineral carbonates in the ALH84001 meteorite; consequently, the identification of Martian processes that form carbonates is critical. This paper reports a previously undescribed carbonate formation process that occurs on Earth and, likely, on Mars. We identified micrometer-sized carbonates in terrestrial aerosols that possess excess (17)O (0.4-3.9‰). The unique O-isotopic composition mechanistically describes the atmospheric heterogeneous chemical reaction on aerosol surfaces. Concomitant laboratory experiments define the transfer of ozone isotopic anomaly to carbonates via hydrogen peroxide formation when O(3) reacts with surface adsorbed water. This previously unidentified chemical reaction scenario provides an explanation for production of the isotopically anomalous carbonates found in the SNC (shergottites, nakhlaites, chassignites) Martian meteorites and terrestrial atmospheric carbonates. The anomalous hydrogen peroxide formed on the aerosol surfaces may transfer its O-isotopic signature to the water reservoir, thus producing mass independently fractionated secondary mineral evaporites. The formation of peroxide via heterogeneous chemistry on aerosol surfaces also reveals a previously undescribed oxidative process of utility in understanding ozone and oxygen chemistry, both on Mars and Earth.

  18. Detection of oxygen isotopic anomaly in terrestrial atmospheric carbonates and its implications to Mars

    PubMed Central

    Shaheen, R.; Abramian, A.; Horn, J.; Dominguez, G.; Sullivan, R.; Thiemens, Mark H.

    2010-01-01

    The debate of life on Mars centers around the source of the globular, micrometer-sized mineral carbonates in the ALH84001 meteorite; consequently, the identification of Martian processes that form carbonates is critical. This paper reports a previously undescribed carbonate formation process that occurs on Earth and, likely, on Mars. We identified micrometer-sized carbonates in terrestrial aerosols that possess excess 17O (0.4–3.9‰). The unique O-isotopic composition mechanistically describes the atmospheric heterogeneous chemical reaction on aerosol surfaces. Concomitant laboratory experiments define the transfer of ozone isotopic anomaly to carbonates via hydrogen peroxide formation when O3 reacts with surface adsorbed water. This previously unidentified chemical reaction scenario provides an explanation for production of the isotopically anomalous carbonates found in the SNC (shergottites, nakhlaites, chassignites) Martian meteorites and terrestrial atmospheric carbonates. The anomalous hydrogen peroxide formed on the aerosol surfaces may transfer its O-isotopic signature to the water reservoir, thus producing mass independently fractionated secondary mineral evaporites. The formation of peroxide via heterogeneous chemistry on aerosol surfaces also reveals a previously undescribed oxidative process of utility in understanding ozone and oxygen chemistry, both on Mars and Earth. PMID:21059939

  19. Molecular Isotopic Characterization of the ALH 85013.50 Meteorite: Defining the Extraterrestrial Organic Compounds

    NASA Technical Reports Server (NTRS)

    Fuller, M.; Huang, Y.

    2003-01-01

    The Antarctic Meteorite Program has returned over 16,000 meteorites from the ice sheets of the Antarctic. This more than doubles the number of preexisting meteorite collection and adds important and rare specimens to the assemblage. The CM carbonaceous chondrites are of particular interest because of their high organic component. The Antarctic carbonaceous chondrites provide a large, previously uninvestigated suite of meteorites. Of the 161 CM chondrites listed in the Catalogue of Meteorites 138 of them have been recovered from the Antarctic ice sheets,. However, these meteorites have typically been exposed to Earth s conditions for long periods of time. The extent of terrestrial organic contamination and weathering that has taken place on these carbonaceous chondrites is unknown. In the past, stable isotope analysis was used to identify bulk organics that were extraterrestrial in origin. Although useful, this method could not exclude the possibility of terrestrial contamination contributing to the isotopic measurement. Compound specific isotope analysis of organic meteorite material has provided the opportunity to discern the terrestrial contamination from extraterrestrial organic compounds on the molecular level.

  20. Geochemistry of Martian Meteorites and the Petrologic Evolution of Mars

    NASA Technical Reports Server (NTRS)

    Mittlefehldt, D. W.

    2002-01-01

    Mafic igneous rocks serve as probes of the interiors of their parent bodies - the compositions of the magmas contain an imprint of the source region composition and mineralogy, the melting and crystallization processes, and mixing and assimilation. Although complicated by their multifarious history, it is possible to constrain the petrologic evolution of an igneous province through compositional study of the rocks. Incompatible trace elements provide one means of doing this. I will use incompatible element ratios of martian meteorites to constrain the early petrologic evolution of Mars. Incompatible elements are strongly partitioned into the melt phase during igneous processes. The degree of incompatibility will differ depending on the mineral phases in equilibrium with the melt. Most martian meteorites contain some cumulus grains, but nevertheless, incompatible element ratios of bulk meteorites will be close to those of their parent magmas. ALH 84001 is an exception, and it will not be discussed. The martian meteorites will be considered in two groups; a 1.3 Ga group composed of the clinopyroxenites and dunite, and a younger group composed of all others.

  1. Solution processed aluminum paper for flexible electronics.

    PubMed

    Lee, Hye Moon; Lee, Ha Beom; Jung, Dae Soo; Yun, Jung-Yeul; Ko, Seung Hwan; Park, Seung Bin

    2012-09-11

    As an alternative to vacuum deposition, preparation of highly conductive papers with aluminum (Al) features is successfully achieved by the solution process consisting of Al precursor ink (AlH(3){O(C(4)H(9))(2)}) and low temperature stamping process performed at 110 °C without any serious hydroxylation and oxidation problems. Al features formed on several kinds of paper substrates (calendar, magazine, and inkjet printing paper substrates) are less than ~60 nm thick, and their electrical conductivities were found to be as good as thermally evaporated Al film or even better (≤2 Ω/□). Strong adhesion of Al features to paper substrates and their excellent flexibility are also experimentally confirmed by TEM observation and mechanical tests, such as tape and bending tests. The solution processed Al features on paper substrates show different electrical and mechanical performance depending on the paper type, and inkjet printing paper is found to be the best substrate with high and stable electrical and mechanical properties. The Al conductive papers produced by the solution process may be applicable in disposal paper electronics.

  2. Inter-observer variability between general pathologists and a specialist in breast pathology in the diagnosis of lobular neoplasia, columnar cell lesions, atypical ductal hyperplasia and ductal carcinoma in situ of the breast

    PubMed Central

    2014-01-01

    Background This study aimed to assess inter-observer variability between the original diagnostic reports and later review by a specialist in breast pathology considering lobular neoplasias (LN), columnar cell lesions (CCL), atypical ductal hyperplasia (ADH), and ductal carcinoma in situ (DCIS) of the breast. Methods A retrospective, observational, cross-sectional study was conducted. A total of 610 breast specimens that had been formally sent for consultation and/or second opinions to the Breast Pathology Laboratory of Federal University of Minas Gerais were analysed between January 2005 and December 2010. The inter-observer variability between the original report and later review was compared regarding the diagnoses of LN, CCL, ADH, and DCIS. Statistical analyses were conducted using the Kappa index. Results Weak correlations were observed for the diagnoses of columnar cell change (CCC; Kappa = 0.38), columnar cell hyperplasia (CCH; Kappa = 0.32), while a moderate agreement (Kappa = 0.47) was observed for the diagnoses of flat epithelial atypia (FEA). Good agreement was observed in the diagnoses of atypical lobular hyperplasia (ALH; Kappa = 0.62) and lobular carcinoma in situ (LCIS; Kappa = 0.66). However, poor agreement was observed for the diagnoses of pleomorphic LCIS (Kappa = 0.22). Moderate agreement was observed for the diagnoses of ADH (Kappa = 0.44), low-grade DCIS (Kappa = 0.47), intermediate-grade DCIS (Kappa = 0.45), and DCIS with microinvasion (Kappa = 0.56). Good agreement was observed between the diagnoses of high-grade DCIS (Kappa = 0.68). Conclusions According to our data, the best diagnostic agreements were observed for high-grade DCIS, ALH, and LCIS. CCL without atypia and pleomorphic LCIS had the worst agreement indices. Virtual Slides The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1640072350119725. PMID:24948027

  3. Antarctic Martian Meteorites at Johnson Space Center

    NASA Technical Reports Server (NTRS)

    Funk, R. C.; Satterwhite, C. E.; Righter, K.; Harrington, R.

    2018-01-01

    This past year marked the 40th anniversary of the first Martian meteorite found in Antarctica by the ANSMET Antarctic Search for Meteorites) program, ALH 77005. Since then, an additional 14 Martian meteorites have been found by the ANSMET program making for a total of 15 Martian meteorites in the U. S. Antarctic meteorite collection at Johnson Space Center (JSC). Of the 15 meteorites, some have been paired so the 15 meteorites actually represent a total of approximately 9 separate samples. The first Martian meteorite found by ANSMET was ALH 77005 (482.500 g), a lherzolitic shergottite. When collected, this meteorite was split as a part of the joint expedition with the National Institute of Polar Research (NIPR) Japan. Originally classified as an "achondrite-unique", it was re-classified as a Martian lherzolitic shergottite in 1982. This meteorite has been allocated to 137 scientists for research and there are 180.934 g remaining at JSC. Two years later, one of the most significant Martian meteorites of the collection at JSC was found at Elephant Moraine, EET 79001 (7942.000 g), a shergottite. This meteorite is the largest in the Martian collection at JSC and was the largest stony meteorite sample collected during the 1979 season. In addition to its size, this meteorite is of particular interest because it contains a linear contact separating two different igneous lithologies, basaltic and olivine-phyric. EET 79001 has glass inclusions that contain noble gas and nitrogen compositions that are proportionally identical to the Martian atmosphere, as measured by the Viking spacecraft. This discovery helped scientists to identify where the "SNC" meteorite suite had originated, and that we actually possessed Martian samples. This meteorite has been allocated to 205 scientists for research and 5,298.435 g of sample is available.

  4. Inter-observer variability between general pathologists and a specialist in breast pathology in the diagnosis of lobular neoplasia, columnar cell lesions, atypical ductal hyperplasia and ductal carcinoma in situ of the breast.

    PubMed

    Gomes, Douglas S; Porto, Simone S; Balabram, Débora; Gobbi, Helenice

    2014-06-19

    This study aimed to assess inter-observer variability between the original diagnostic reports and later review by a specialist in breast pathology considering lobular neoplasias (LN), columnar cell lesions (CCL), atypical ductal hyperplasia (ADH), and ductal carcinoma in situ (DCIS) of the breast. A retrospective, observational, cross-sectional study was conducted. A total of 610 breast specimens that had been formally sent for consultation and/or second opinions to the Breast Pathology Laboratory of Federal University of Minas Gerais were analysed between January 2005 and December 2010. The inter-observer variability between the original report and later review was compared regarding the diagnoses of LN, CCL, ADH, and DCIS. Statistical analyses were conducted using the Kappa index. Weak correlations were observed for the diagnoses of columnar cell change (CCC; Kappa=0.38), columnar cell hyperplasia (CCH; Kappa=0.32), while a moderate agreement (Kappa=0.47) was observed for the diagnoses of flat epithelial atypia (FEA). Good agreement was observed in the diagnoses of atypical lobular hyperplasia (ALH; Kappa=0.62) and lobular carcinoma in situ (LCIS; Kappa=0.66). However, poor agreement was observed for the diagnoses of pleomorphic LCIS (Kappa=0.22). Moderate agreement was observed for the diagnoses of ADH (Kappa=0.44), low-grade DCIS (Kappa=0.47), intermediate-grade DCIS (Kappa=0.45), and DCIS with microinvasion (Kappa=0.56). Good agreement was observed between the diagnoses of high-grade DCIS (Kappa=0.68). According to our data, the best diagnostic agreements were observed for high-grade DCIS, ALH, and LCIS. CCL without atypia and pleomorphic LCIS had the worst agreement indices. The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1640072350119725.

  5. 40 Years of Collecting Martian Meteorites

    NASA Technical Reports Server (NTRS)

    Funk, R. C.; Sattershite, C. E.; Righter, K.; Harrington, R.

    2017-01-01

    meteorite in 1993 [3,4]. ALH 84001 is known as the "Life on Mars" meteorite, sparked debate about whether it contained evidence of Martian life [5] and significantly influenced the field of astrobiol-ogy. This sample has been allocated to 173 scientists for research and has 1426.694 g remaining at JSC. In 1988, another lherzolitic shergottite was found, LEW 88516, (13.203 g). This meteorite wasn't recognized in the field as an achondrite until it was broken during processing 2 years later. LEW 88516 has been allocated to 43 scientists for research and 5.351 g of this meteorite remains at JSC. Six years later a basaltic shergottite was found in the Queen Alexandra Range, QUE 94201 (12.020 g). This meteorite was believed to be of terrestrial origin until maskelynite was seen in a thin section. QUE 94201 has been allocated to 57 scientists for research and there are 3.629 g of this meteorite left at JSC. In 2003, the NASA Mars Exploration Program joined the ANSMET team with the hopes of finding another Martian mete-orite. During this expedition, MIL 03346 (715.200 g) was found. This meteorite is a nakhlite. MIL 03346 has been allocated to 98 scientists for research and there are 579.046 g of this sample remaining at JSC. Six years later, 3 more meteorites that have been paired with MIL 03346 were found, MIL 090030 (452.630 g), 090032 (532.190 g ) and 090136 (170.980 g). MIL 090030 has been allocated to 21 scientists for research and has 434.420 g remaining at JSC, MIL 090032 has been allocated to 21 scientists for re-search and has 508.710 g remaining at JSC and MIL 090136 has been allocated to 14 scientists for research and has 156.790 g remaining at JSC. During the 2004 expedition, 2 identical meteorites where found together on the ice, RBT 04261 (78.763 g) and RBT 04262 (204.600 g). These paired meteorites are olivine-phyric shergottites. RBT 04261 has been allocated to 33 scientists for research and has 32.335 g remaining at JSC. RBT 04262 has been allocated to 46

  6. Identification of carbonate-rich outcrops on Mars by the Spirit rover.

    PubMed

    Morris, Richard V; Ruff, Steven W; Gellert, Ralf; Ming, Douglas W; Arvidson, Raymond E; Clark, Benton C; Golden, D C; Siebach, Kirsten; Klingelhöfer, Göstar; Schröder, Christian; Fleischer, Iris; Yen, Albert S; Squyres, Steven W

    2010-07-23

    Decades of speculation about a warmer, wetter Mars climate in the planet's first billion years postulate a denser CO2-rich atmosphere than at present. Such an atmosphere should have led to the formation of outcrops rich in carbonate minerals, for which evidence has been sparse. Using the Mars Exploration Rover Spirit, we have now identified outcrops rich in magnesium-iron carbonate (16 to 34 weight percent) in the Columbia Hills of Gusev crater. Its composition approximates the average composition of the carbonate globules in martian meteorite ALH 84001. The Gusev carbonate probably precipitated from carbonate-bearing solutions under hydrothermal conditions at near-neutral pH in association with volcanic activity during the Noachian era.

  7. A Howardite-Eucrite-Diogenite (HED) Meteorite Compendium: Summarizing Samples of ASteroid 4 Vesta in Preparation for the Dawn Mission

    NASA Technical Reports Server (NTRS)

    Garber, J. M.; Righter, K.

    2011-01-01

    The Howardite-Eucrite-Diogenite (HED) suite of achondritic meteorites, thought to originate from asteroid 4 Vesta, has recently been summarized into a meteorite compendium. This compendium will serve as a guide for researchers interested in further analysis of HEDs, and we expect that interest in these samples will greatly increase with the planned arrival of the Dawn Mission at Vesta in August 2011. The focus of this abstract/poster is to (1) introduce and describe HED samples from both historical falls and Antarctic finds, and (2) provide information on unique HED samples available for study from the Antarctic Meteorite Collection at JSC, including the vesicular eucrite PCA91007, the olivine diogenite EETA79002, and the paired ALH polymict eucrites.

  8. In vitro sperm characterization and development of a sperm cryopreservation method using directional solidification in the killer whale (Orcinus orca).

    PubMed

    Robeck, T R; Gearhart, S A; Steinman, K J; Katsumata, E; Loureiro, J D; O'Brien, J K

    2011-07-15

    Research was conducted to characterize seminal traits and to develop a sperm cryopreservation method using directional freezing (DF) for the killer whale (Orcinus orca). Experiments evaluated effects of: (i) freezing rate (SLOW, MED, FAST) by diluent (BF5F, Biladyl®, EYC) in 0.5 mL straws; and (ii) freezing method (straw or DF) by glycerol (3, 6, or 9% final concentration, v:v) on in vitro sperm quality. Fresh ejaculates (n = 161) were (mean ± SD) 7.8 ± 7.4 mL at 740 × 10(6) sperm/mL with 92.2 ± 6.3% total motility (TM), 85.4 ± 6.9% progressive motility (PM), 89.6 ± 9.0% viability and 89.8 ± 9.2% acrosome integrity. Samples frozen using straws by the MED or SLOW method were improved (P < 0.05) over FAST across all diluents. At 3 h post thaw (PT), TM, PM, Rapid motility (RM), VAP, VCL, ALH and viability for 3% and 6% glycerol were improved (P < 0.05) over 9% glycerol. Directional freezing samples at 0 h and 3 h PT, at all glycerol concentrations, displayed higher (P < 0.001) TM, PM, RM, VAP, VSL, VCL and viability /intact acrosomes (PI/FITC-PNA) than straw. These data provided the first information on ejaculate characteristics and the development of a semen cryopreservation method using DF in the killer whale. Copyright © 2011 Elsevier Inc. All rights reserved.

  9. Possible impact-induced refractory-lithophile fractionations in EL chondrites

    NASA Astrophysics Data System (ADS)

    Rubin, Alan E.; Huber, Heinz; Wasson, John T.

    2009-03-01

    Literature data show that refractory-lithophile elements in most chondrite groups are unfractionated relative to CI chondrites; the principal exception is the EL-chondrite group whose observed falls (all of which are type 6) are depleted in Ca and light REE. In contrast, literature data and our new INAA data on EL3 PCA 91020, EL3 MAC 88136 and EL4 Grein 002 show that some replicates of these samples have nearly flat REE patterns (unlike those of EL6 chondrites); other replicates exhibit fractionated REE patterns similar to those of EL6 chondrites. Petrographic examination shows that many EL6 (and some EL3 and EL4) chondrites are impact-melt breccias or contain impact-melted portions. We suggest that the same impact processes that formed these breccias and produced melt are responsible for the observed bulk compositional fractionations in refractory-lithophile elements, i.e., EL6 chondrites were produced from initially unequilibrated EL3 material. When large amounts of impact heat were deposited, plagioclase and/or oldhamite (CaS) (the major REE carriers in enstatite chondrites) may have been melted and then transported appreciable (>10 cm) distances. EL6 chondrites represent the residuum that is depleted in REE (particularly in LREE) and Ca. Unlike the case for EL chondrites, our new INAA data on ALH 84170, EET 87746 and SAH 97096 (all EH3) show some scatter but are consistent with the EH group having uniform refractory-lithophile abundances.

  10. Meteorite constraints on Martian atmospheric loss and paleoclimate

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

    Cassata, William S.

    The evolution of Mars' atmosphere to its currently thin state incapable of supporting liquid water remains poorly understood and has important implications for Martian climate history. Martian meteorites contain trapped atmospheric gases that can be used to constrain both the timing and effectiveness of atmospheric escape processes. Here in this article, measurements of xenon isotopes in two ancient Martian meteorites, ALH 84001 and NWA 7034, are reported. The data indicate an early episode of atmospheric escape that mass fractionated xenon isotopes culminated within a few hundred million years of planetary formation, and little change to the atmospheric xenon isotopic compositionmore » has occurred since this time. In contrast, on Earth atmospheric xenon fractionation continued for at least two billion years (Pujol et al., 2011). Such differences in atmospheric Xe fractionation between the two planets suggest that climate conditions on Mars may have differed significantly from those on Archean Earth. For example, the hydrogen escape flux may not have exceeded the threshold required for xenon escape on Mars after 4.2–4.3 Ga, which indicates that Mars may have been significantly drier than Earth after this time.« less

  11. Meteorite constraints on Martian atmospheric loss and paleoclimate

    DOE PAGES

    Cassata, William S.

    2017-10-06

    The evolution of Mars' atmosphere to its currently thin state incapable of supporting liquid water remains poorly understood and has important implications for Martian climate history. Martian meteorites contain trapped atmospheric gases that can be used to constrain both the timing and effectiveness of atmospheric escape processes. Here in this article, measurements of xenon isotopes in two ancient Martian meteorites, ALH 84001 and NWA 7034, are reported. The data indicate an early episode of atmospheric escape that mass fractionated xenon isotopes culminated within a few hundred million years of planetary formation, and little change to the atmospheric xenon isotopic compositionmore » has occurred since this time. In contrast, on Earth atmospheric xenon fractionation continued for at least two billion years (Pujol et al., 2011). Such differences in atmospheric Xe fractionation between the two planets suggest that climate conditions on Mars may have differed significantly from those on Archean Earth. For example, the hydrogen escape flux may not have exceeded the threshold required for xenon escape on Mars after 4.2–4.3 Ga, which indicates that Mars may have been significantly drier than Earth after this time.« less

  12. Al-Coated Conductive Fiber Filters for High-Efficiency Electrostatic Filtration: Effects of Electrical and Fiber Structural Properties.

    PubMed

    Choi, Dong Yun; An, Eun Jeong; Jung, Soo-Ho; Song, Dong Keun; Oh, Yong Suk; Lee, Hyung Woo; Lee, Hye Moon

    2018-04-10

    Through the direct decomposition of an Al precursor ink AlH 3 {O(C 4 H 9 ) 2 }, we fabricated an Al-coated conductive fiber filter for the efficient electrostatic removal of airborne particles (>99%) with a low pressure drop (~several Pascals). The effects of the electrical and structural properties of the filters were investigated in terms of collection efficiency, pressure drop, and particle deposition behavior. The collection efficiency did not show a significant correlation with the extent of electrical conductivity, as the filter is electrostatically charged by the metallic Al layers forming electrical networks throughout the fibers. Most of the charged particles were collected via surface filtration by Coulombic interactions; consequently, the filter thickness had little effect on the collection efficiency. Based on simulations of various fiber structures, we found that surface filtration can transition to depth filtration depending on the extent of interfiber distance. Therefore, the effects of structural characteristics on collection efficiency varied depending on the degree of the fiber packing density. This study will offer valuable information pertaining to the development of a conductive metal/polymer composite air filter for an energy-efficient and high-performance electrostatic filtration system.

  13. Measurement Of Hydrogen Capacities And Stability In Thin Films Of AlH Deposited By Magnetron Sputtering

    NASA Astrophysics Data System (ADS)

    Dissanayake, A.; AlFaify, S.; Garratt, E.; Nandasiri, M. I.; Taibu, R.; Tecos, G.; Hamdan, N. M.; Kayani, A.

    2011-06-01

    Thin, hydrogenated aluminum hydride films were deposited on silicon substrates using unbalanced magnetron (UBM) sputtering of a high purity aluminum target under electrically grounded conditions. Argon was used as sputtering gas and hydrogenation was carried out by diluting the growth plasma with hydrogen. The effect of hydrogen partial pressure on the final concentration of trapped elements including hydrogen has been studied using ion beam analysis (IBA) techniques. Moreover, in-situ thermal stability of trapped hydrogen in the film was carried out using Rutherford Backscattering Spectrometry (RBS), Non-Rutherford Backscattering Spectrometry (NRBS) and Elastic Recoil Detection Analysis (ERDA). Microstructure of the film was investigated by SEM analysis. Hydrogen content in the thin films was found decreasing as the films were heated above 110 °C in vacuum.

  14. Measuring Health-Related Quality of Life of HIV-Positive Adolescents in Resource-Constrained Settings

    PubMed Central

    Masquillier, Caroline; Wouters, Edwin; Loos, Jasna; Nöstlinger, Christiana

    2012-01-01

    Background and Objectives Access to antiretroviral treatment among adolescents living with HIV (ALH) is increasing. Health-related quality of life (HRQOL) is relevant for monitoring the impact of the disease on both well-being and treatment outcomes. However, adequate screening tools to assess HRQOL in low-resource settings are scarce. This study aims to fill this research gap, by 1) assessing the psychometric properties and reliability of an Eastern African English version of a European HRQOL scale for adolescents (KIDSCREEN) and 2) determining which version of the KIDSCREEN (52-, 27- and 10-item version) is most suitable for low-resource settings. Methods The KIDSCREEN was translated into Eastern African English, Luganda (Uganda) and Dholuo (Kenya) according to standard procedures. The reconciled version was administered in 2011 to ALH aged 13–17 in Kenya (n = 283) and Uganda (n = 299). All three KIDSCREEN versions were fitted to the data with confirmatory factor analysis (CFA). After comparison, the most suitable version was adapted based on the CFA outcomes utilizing the results of previous formative research. In order to develop a general HRQOL factor, a second-order measurement model was fitted to the data. Results The CFA results showed that without adjustments, the KIDSCREEN cannot be used for measuring the HRQOL of HIV-positive adolescents. After comparison, the most suitable version for low-resource settings - the 27-item version - was adapted further. The introduction of a negative wording factor was required for the Dholuo model. The Dholuo (CFI: 0.93; RMSEA: 0.039) and the Luganda model (CFI: 0.90; RMSEA: 0.052) showed a good fit. All cronbach’s alphas of the factors were 0.70 or above. The alpha value of the Dholuo and Lugandan HRQOL second-order factor was respectively 0.84 and 0.87. Conclusions The study showed that the adapted KIDSCREEN-27 is an adequate tool for measuring HRQOL in low-resource settings with high HIV prevalence. PMID

  15. Does isolated flat epithelial atypia on vacuum-assisted breast core biopsy require surgical excision?

    PubMed

    Dialani, Vandana; Venkataraman, Shambhavi; Frieling, Gretchen; Schnitt, Stuart J; Mehta, Tejas S

    2014-01-01

    To determine whether flat epithelial atypia (FEA) found in isolation on large core vacuum-assisted biopsy (CNB) requires surgical excision. After Institutional Review Board approval, pathology reports of all patients who underwent CNB from January 1, 2005 to December 31, 2010 were reviewed. All patients with reports of isolated FEA without other atypia or in situ or invasive carcinoma were identified. Patient age, history, target on imaging, biopsy modality, and residual target post CNB noted. Histology of CNB's (blinded to surgical outcome) and subsequent surgical excisions were reviewed by a dedicated breast pathologist. Only cases with confirmed isolated FEA on review were used for data analysis. Of 2,556 CNB's performed over 6 years, 37 (1.4%) had isolated FEA confirmed on review, comprising our study population. Thirty (81%) had biopsy for calcifications on mammography and 7 (19%) for mass or non-mass like enhancement on magnetic resonance imaging. There were no US guided CNBs that met our inclusion criteria. 29 (78.4%) underwent surgical excision, 6 (16.2%) had imaging follow-up, and 2 (5.4%) were lost to follow-up. Of the 29 with surgery, 2 (6.9%) had "upgrade" to low-grade in situ carcinoma (1 ductal and 1 pleomorphic lobular), 5 (17.2%) had "change in diagnosis" to other atypia (ADH/ALH), 15 (51.7%) had additional FEA and 7 (24.2%) had benign tissue without atypia. Both "upgraded" cases had residual microcalcifications on imaging following CNB. There were no upgrades to invasive cancers. In our study, none of 29 with isolated FEA on CNB had invasive cancer on surgical excision. If there are residual microcalcifications or residual lesion after a CNB that shows isolated FEA, excision is warranted, due to the possibility of other atypia (ADH/ALH [17.2%] or DCIS [5.4%]). If there are no residual microcalcifications following CNB, imaging follow-up as an alternative to surgery may be a reasonable option. © 2014 Wiley Periodicals, Inc.

  16. Sampling factors influencing accuracy of sperm kinematic analysis.

    PubMed

    Owen, D H; Katz, D F

    1993-01-01

    Sampling conditions that influence the accuracy of experimental measurement of sperm head kinematics were studied by computer simulation methods. Several archetypal sperm trajectories were studied. First, mathematical models of typical flagellar beats were input to hydrodynamic equations of sperm motion. The instantaneous swimming velocities of such sperm were computed over sequences of flagellar beat cycles, from which the resulting trajectories were determined. In a second, idealized approach, direct mathematical models of trajectories were utilized, based upon similarities to the previous hydrodynamic constructs. In general, it was found that analyses of sampling factors produced similar results for the hydrodynamic and idealized trajectories. A number of experimental sampling factors were studied, including the number of sperm head positions measured per flagellar beat, and the time interval over which these measurements are taken. It was found that when one flagellar beat is sampled, values of amplitude of lateral head displacement (ALH) and linearity (LIN) approached their actual values when five or more sample points per beat were taken. Mean angular displacement (MAD) values, however, remained sensitive to sampling rate even when large sampling rates were used. Values of MAD were also much more sensitive to the initial starting point of the sampling procedure than were ALH or LIN. On the basis of these analyses of measurement accuracy for individual sperm, simulations were then performed of cumulative effects when studying entire populations of motile cells. It was found that substantial (double digit) errors occurred in the mean values of curvilinear velocity (VCL), LIN, and MAD under the conditions of 30 video frames per second and 0.5 seconds of analysis time. Increasing the analysis interval to 1 second did not appreciably improve the results. However, increasing the analysis rate to 60 frames per second significantly reduced the errors. These findings

  17. Investigations into an unknown organism on the martian meteorite Allan Hills 84001

    NASA Technical Reports Server (NTRS)

    Steele, A.; Goddard, D. T.; Stapleton, D.; Toporski, J. K.; Peters, V.; Bassinger, V.; Sharples, G.; Wynn-Williams, D. D.; McKay, D. S.

    2000-01-01

    Examination of fracture surfaces near the fusion crust of the martian meteorite Allan Hills (ALH) 84001 have been conducted using scanning electron microscopy (SEM) and atomic force microscopy (AFM) and has revealed structures strongly resembling mycelium. These structures were compared with similar structures found in Antarctic cryptoendolithic communities. On morphology alone, we conclude that these features are not only terrestrial in origin but probably belong to a member of the Actinomycetales, which we consider was introduced during the Antarctic residency of this meteorite. If true, this is the first documented account of terrestrial microbial activity within a meteorite from the Antarctic blue ice fields. These structures, however, do not bear any resemblance to those postulated to be martian biota, although they are a probable source of the organic contaminants previously reported in this meteorite.

  18. Isotope Variations in Terrestrial Carbonates and Thermal Springs as Biomarkers: Analogs for Martian Processes

    NASA Technical Reports Server (NTRS)

    Socki, Richard A.; Gibson, Everett K., Jr.; Bissada, K. K.

    2006-01-01

    Stable isotope measurements of carbonate minerals contained within ALH84001 [1] suggest that fluids were present at 3.9 Gy on Mars [2, 3, 4, 5]. Both oxygen and carbon isotopes provide independent means of deciphering paleoenvironmental conditions at the time of carbonate mineral precipitation. In terrestrial carbonate rocks oxygen isotopes not only indicate the paleotemperature of the precipitating fluid, but also provide clues to environmental conditions that affected the fluid chemistry. Carbon isotopes, on the other hand, can indicate the presence or absence of organic compounds during precipitation (i.e. biogenically vs. thermogenically-generated methane), thus serving as a potential biomarker. We have undertaken a study of micro scale stable isotope variations measured in some terrestrial carbonates and the influence of organic compounds associated with the formation of these carbonates. Preliminary results indicate that isotope variations occur within narrow and discrete intervals, providing clues to paleoenvironmental conditions that include both biological and non-biological activity. These results carry implications for deciphering Martian isotope data and therefore potential biological prospecting on the planet Mars. Recently, Fourier Transform Spectrometer observations have detected methane occurring in the Martian atmosphere [6] that could be attributed to a possible biogenic source. Indeed, Mars Express has detected the presence of methane in the Martian atmosphere [7], with evidence indicating that methane abundances are greatest above those basins with high water concentrations.

  19. Carbonate Cements from the Sverrefjell and Sigurdfjell Volcanoes, Svalbard Norway: Analogs for Martian Carbonates

    NASA Technical Reports Server (NTRS)

    Blake, D. F.; Treiman, A. H.; Morris, R.; Bish, D.; Amundsen, H.E.F.; Steele, A.

    2011-01-01

    The Sverrefjell and Sigurdfjell volcanic complexes erupted at 1Ma on Svalbard, Norway. Sverrefjell is a cone of cinders, pillow lavas and dikes; Sigurdfjell is elongate in outcrop and may represent a fissure eruption [1]. The lavas of both volcanos were volatile rich. The volcanos erupted under ice and were subsequently dissected by glaciation (glacial eratics are present on most of Sverrefjell, even on its summit). Eruption beneath an ice sheet is inferred, based on the presence of pillow lavas from near sea level to 1000 m above sea level. Sverrefjell contains the largest fraction of ultramafic xenoliths of any volcanic complex in the world, in places accounting for as much as 50% of the volume of the outcrop. The Sverrefjell and Sigurdfell volcanos contain carbonate cements of several varieties: (1) Amundsen [2] reported Mg-Fe-rich carbonate in sub-mm globules in basalts and ultramafic xenoliths from the volcanos. These globules are the best terrestrial analogs to the carbonate globules in the Mars meteorite ALH84001 [3]. (2) Thick (1-3 cm) coatings of carbonate cement drape the walls of vertical volcanic pipes or conduits on the flanks and near the present summit of Sverrefjell. Similar occurrences are found on Sigurdfjell. (3) Breccia-filled pipes or vents occur on Sverrefjell and Siggurdfjell in which the breccia fragments are cemented by carbonate. The fragments themselves commonly contain carbonate globules similar to those found in the basalts and ultramafic xenoliths.

  20. The Valence of Iron in CM Chondrite Serpentine as Measured by Synchrotron Xanes

    NASA Technical Reports Server (NTRS)

    Mikouchi, T.; Zolensky, Michael E.; Satake, W.; Le, L.

    2012-01-01

    Fe-bearing phyllosilicates are the dominant product of aqueous alteration in carbonaceous chondrites, and serpentine is the most abundant phyllosilicate in CM2 chondrites that are the most abundant carbonaceous chondrite. Browning et al. predicted that Fe(3+)/(sum of Fe) ratios of serpentine in CM chondrites should change with progressive alteration. They proposed that progressive CM alteration is best monitored by evaluating the progress of Si and Fe3+ substitutions that necessarily attend the transition from end-member cronstedtite to serpentine. Their proposed Mineralogic Alteration Index, 2-(Fe(3+)/(2-Si)), was intended to highlight and utilize the relevant ex-change information in the stoichiometric phyllosilicate formulas based upon the coupled substitution of 2(Fe(3+), Al) = Si + (Mg, Fe(2+)...) in serpentine. The value of this ratio increases as alteration proceeds. We always wanted to directly test Browning s pre-diction through actual measurements of the Fe3+ con-tent of serpentine at the micron scale appropriate to EPMA analyses (Zega et al. have measured it at much finer scale), and this test can now be made using Synchrotron Radiation X-ray Absorption Near-Edge Structure (SR-XANES). Thus, we have recently begun investigation with CMs that span a large portion of the range of observed aqueous alteration, and we first analyzed Murray, Nogoya, and ALH84029 by SR-XANES. However, we did not find clear correlation between Fe3+/(sum of Fe) ratios of serpentine and their alteration degrees. We thus analyzed serpentine in three more CMs and here report their Fe3+/(sum of Fe) ratios in comparison with our previous results.

  1. Microbial Contamination of Allende and Murchison Carbonaceous Chondrites; Developing a Protocol for Life Detection in Extraterrestrial Materials Using Biotechnology

    NASA Technical Reports Server (NTRS)

    Steele, A.; Whitby, C.; Griffin, C.; Toporski, J. K. W.; Westall, F.; Saunders, J. R.; McKay, D. S.

    2001-01-01

    The arguments used to refute the McKay et al., (1996) hypothesis of possible Martian life in ALH84001 failed to use contamination of the meteorite as a source. This has worrying implications for our ability to detect terrestrial microbiota in meteorites and therefore any potential extraterrestrial biosignatures in both meteorites and possible returned samples. We report on imaging and microbial culturing of both Allende and Murchison carbonaceous chondrites and on the use of molecular biology techniques on a sample of Allende. Contaminating fungi and bacteria were observed (in the case of Murchison) and cultured from both meteorites. DNA was successfully extracted and subsequent PCR showed the presence of both bacterial and fungal DNA although no Archaea were detected. These results show that it is possible to use molecular biological techniques on very small quantities (300 mg) of extraterrestrial material.

  2. Scanning Electron Microscopy Investigation of a Sample Depth Profile Through the Martian Meteorite Nakhla

    NASA Technical Reports Server (NTRS)

    Toporski, Jan; Steele, Andrew; Westall, Frances; McKay, David S.

    2000-01-01

    The ongoing scientific debate as to whether or not the Martian meteorite ALH84001 contained evidence of possible biogenic activities showed the need to establish consistent methods to ascertain the origin of such evidence. To distinguish between terrestrial organic material/microbial contaminants and possible indigenous microbiota within meteorites is therefore crucial. With this in mind a depth profile consisting of four samples from a new sample allocation of Martian meteorite Nakhla was investigated using scanning electron microscopy (SEM) and energy dispersive X-ray analysis. SEM imaging of freshly broken fractured chips revealed structures strongly recent terrestrial microorganisms, in some cases showing evidence of active growth. This conclusion was supported by EDX analysis, which showed the presence of carbon associated with these structures, we concluded that these structures represent recent terrestrial contaminants rather than structures indigenous to the meteorite. Page

  3. [Detection of organic compounds on Mars].

    PubMed

    Kobayashi, K

    1997-03-01

    McKay et al. detected polycyclic aromatic hydrocarbons (PAHs) in Martian meteorite ALH 84001 by two-step laser mass spectrometry. From the presence of PAHs, together with other results, they concluded that there were past life of Mars. On the other hands, no organisms nor organic compounds were detected in Martian regolith in Viking experiments in 1976. In order to obtain solid evidence for organisms or bioorganic compounds compounds on Mars, further analyses of Martian samples are required. There may be four classes of organic compounds on Mars, which are (i) organic compounds abiotically formed from primitive Mars atmosphere, (ii) Organic compounds delivered out of Mars, (iii) Organic compounds biotically formed by Mars organisms, and (iv) Organic compounds abiotically formed from the present Mars atmosphere. Possible organic compounds on Mars and analytical methods for them are discussed.

  4. Preliminary Interpretations of Atmospheric Stable Isotopes and Argon from Mars Science Laboratory (SAM)

    NASA Technical Reports Server (NTRS)

    Jones, J. H.; Niles, P. B.; Webster, C. R.; Mahaffy, P. R.; Flesch, G. J.; Christensen, L. E.; Leshin, L. A.; Franz, H.; Wong, M.; Atreya, S. K.; hide

    2013-01-01

    Given the broad agreement between C, H, and O isotopic ratios in the modern atmosphere and the ALH 84001 meteorite, it is possible that these reservoirs were established after early atmospheric loss prior to 4 Ga. The preservation of these signals over this long period of history can be explained in several slightly different ways: 1) C, O, and H have remained static in the atmosphere and have not exchanged with the surface over the past 4 Ga; 2) C, O, and H in the atmosphere have potentially varied widely over history but have been continually buffered by larger reservoirs in the crust which have remained unchanged over the past 4 Ga. This second possibility allows for potentially large variations in atmospheric pressure to occur as CO2 is recycled back into the atmosphere from crustal reservoirs or degassed from the mantle.

  5. WATEQ4F - a personal computer Fortran translation of the geochemical model WATEQ2 with revised data base

    USGS Publications Warehouse

    Ball, J.W.; Nordstrom, D. Kirk; Zachmann, D.W.

    1987-01-01

    A FORTRAN 77 version of the PL/1 computer program for the geochemical model WATEQ2, which computes major and trace element speciation and mineral saturation for natural waters has been developed. The code (WATEQ4F) has been adapted to execute on an IBM PC or compatible microcomputer. Two versions of the code are available, one operating with IBM Professional FORTRAN and an 8087 or 89287 numeric coprocessor, and one which operates without a numeric coprocessor using Microsoft FORTRAN 77. The calculation procedure is identical to WATEQ2, which has been installed on many mainframes and minicomputers. Limited data base revisions include the addition of the following ions: AlHS04(++), BaS04, CaHS04(++), FeHS04(++), NaF, SrC03, and SrHCO3(+). This report provides the reactions and references for the data base revisions, instructions for program operation, and an explanation of the input and output files. Attachments contain sample output from three water analyses used as test cases and the complete FORTRAN source listing. U.S. Geological Survey geochemical simulation program PHREEQE and mass balance program BALANCE also have been adapted to execute on an IBM PC or compatible microcomputer with a numeric coprocessor and the IBM Professional FORTRAN compiler. (Author 's abstract)

  6. Optical response of the sodium alanate system: GW0-BSE calculations and thin film measurements

    NASA Astrophysics Data System (ADS)

    van Setten, M. J.; Gremaud, R.; Brocks, G.; Dam, B.; Kresse, G.; de Wijs, G. A.

    2011-01-01

    We calculate from first principles the optical spectra of the hydrides in the sodium alanate hydrogen storage system: NaH, NaAlH4, and Na3AlH6. In particular we study the effects of systematic improvements of the theoretical description. To benchmark the calculations we also measure the optical response of a thin film of NaH. The simplest calculated dielectric functions are based upon independent electrons and holes, whose spectrum is obtained at the G0W0 level. Successive improvements consist of including partial self-consistency (so-called GW0) and account for excitonic effects, using the Bethe-Salpeter equation (BSE). Each improvement gives a sizable blue shift or red shift of the dielectric functions, but conserves the trend in the optical gap among different materials. Whereas these shifts partially cancel at the highest (GW0-BSE) level of approximation, the shape of the dielectric functions is strongly modified by excitonic effects. Calculations at the GW0-BSE level give a good agreement with the dielectric function of NaH extracted from the measurements. It demonstrates that the approach can be used for a quantitative interpretation of spectra in novel hydrogen storage materials obtained via, e.g., hydrogenography.

  7. Modeling of a thermal energy storage system based on coupled metal hydrides (magnesium iron – sodium alanate) for concentrating solar power plants

    DOE PAGES

    d'Entremont, A.; Corgnale, C.; Sulic, M.; ...

    2017-08-31

    Concentrating solar power plants represent low cost and efficient solutions for renewable electricity production only if adequate thermal energy storage systems are included. Metal hydride thermal energy storage systems have demonstrated the potential to achieve very high volumetric energy densities, high exergetic efficiencies, and low costs. The current work analyzes the technical feasibility and the performance of a storage system based on the high temperature Mg 2FeH 6 hydride coupled with the low temperature Na 3AlH 6 hydride. To accomplish this, a detailed transport model has been set up and the coupled metal hydride system has been simulated based onmore » a laboratory scale experimental configuration. Proper kinetics expressions have been developed and included in the model to replicate the absorption and desorption process in the high temperature and low temperature hydride materials. The system showed adequate hydrogen transfer between the two metal hydrides, with almost complete charging and discharging, during both thermal energy storage and thermal energy release. The system operating temperatures varied from 450°C to 500°C, with hydrogen pressures between 30 bar and 70 bar. This makes the thermal energy storage system a suitable candidate for pairing with a solar driven steam power plant. The model results, obtained for the selected experimental configuration, showed an actual thermal energy storage system volumetric energy density of about 132 kWh/m 3, which is more than 5 times the U.S. Department of Energy SunShot target (25 kWh/m 3).« less

  8. Thermochemistry of Alane Complexes for Hydrogen Storage: A Theoretical and Experimental Investigation

    PubMed Central

    2011-01-01

    Knowledge of the relative stabilities of alane (AlH3) complexes with electron donors is essential for identifying hydrogen storage materials for vehicular applications that can be regenerated by off-board methods; however, almost no thermodynamic data are available to make this assessment. To fill this gap, we employed the G4(MP2) method to determine heats of formation, entropies, and Gibbs free energies of formation for 38 alane complexes with NH3−nRn (R = Me, Et; n = 0−3), pyridine, pyrazine, triethylenediamine (TEDA), quinuclidine, OH2−nRn (R = Me, Et; n = 0−2), dioxane, and tetrahydrofuran (THF). Monomer, bis, and selected dimer complex geometries were considered. Using these data, we computed the thermodynamics of the key formation and dehydrogenation reactions that would occur during hydrogen delivery and alane regeneration, from which trends in complex stability were identified. These predictions were tested by synthesizing six amine−alane complexes involving trimethylamine, triethylamine, dimethylethylamine, TEDA, quinuclidine, and hexamine and obtaining upper limits of ΔG° for their formation from metallic aluminum. Combining these computational and experimental results, we establish a criterion for complex stability relevant to hydrogen storage that can be used to assess potential ligands prior to attempting synthesis of the alane complex. On the basis of this, we conclude that only a subset of the tertiary amine complexes considered and none of the ether complexes can be successfully formed by direct reaction with aluminum and regenerated in an alane-based hydrogen storage system. PMID:22962624

  9. Modeling of a thermal energy storage system based on coupled metal hydrides (magnesium iron – sodium alanate) for concentrating solar power plants

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

    d'Entremont, A.; Corgnale, C.; Sulic, M.

    Concentrating solar power plants represent low cost and efficient solutions for renewable electricity production only if adequate thermal energy storage systems are included. Metal hydride thermal energy storage systems have demonstrated the potential to achieve very high volumetric energy densities, high exergetic efficiencies, and low costs. The current work analyzes the technical feasibility and the performance of a storage system based on the high temperature Mg 2FeH 6 hydride coupled with the low temperature Na 3AlH 6 hydride. To accomplish this, a detailed transport model has been set up and the coupled metal hydride system has been simulated based onmore » a laboratory scale experimental configuration. Proper kinetics expressions have been developed and included in the model to replicate the absorption and desorption process in the high temperature and low temperature hydride materials. The system showed adequate hydrogen transfer between the two metal hydrides, with almost complete charging and discharging, during both thermal energy storage and thermal energy release. The system operating temperatures varied from 450°C to 500°C, with hydrogen pressures between 30 bar and 70 bar. This makes the thermal energy storage system a suitable candidate for pairing with a solar driven steam power plant. The model results, obtained for the selected experimental configuration, showed an actual thermal energy storage system volumetric energy density of about 132 kWh/m 3, which is more than 5 times the U.S. Department of Energy SunShot target (25 kWh/m 3).« less

  10. Discovery of Carbonate-Rich Outcrops in the Gusev Crater Columbia Hills by the MER Rover Spirit

    NASA Technical Reports Server (NTRS)

    Morris, Richard V.; Ruff, Steven W.; Gellert, Ralf; Ming, Douglas W.; Arvidson, Raymond E.; Clark, Benton C.; Golden, Dadi C.; Siebach, Kirsten L.; Klingelhoefer, Goestar; Schroeder, Christian; hide

    2010-01-01

    The chemical composition, global abundance, distribution, and formation pathways of carbonates are central to understanding aqueous processes, climate, and habitability of early Mars. The Mars Exploration Rover (MER) Spirit analyzed a series of olivine-rich outcrops while descending from the summit region of Husband Hill into the Inner Basin of the Columbia Hills of Gusev Crater to the eastern edge of the El Dorado ripple field in late 2005. Reanalysis of Spirit s mineralogical data from the Moessbauer Spectrometer (MB) and the Miniature Thermal Emission Spectrometer (Mini-TES) and chemical data from the Alpha Particle X-Ray Spectrometer (APXS) in 2010, coupled with new laboratory data for carbonate-bearing samples, lead to identification of carbonate in one of the outcrops (Comanche) [Morris, R.V., et al., Science, 329, 421-424]. The carbonate is rich in magnesium and iron (Mc62Sd25Cc11Rh2, assuming all Ca and Mn is associated with the carbonate) and is a major component of the Comanche outcrops (16 to 34 wt.%). The mineralogical, chemical, and abundance data are constrained in multiple, mutually consistent ways by the MER analyses. For example, a low-Ca carbonate is required by the MB and APXS data and is consistent with Mini-TES data. Three spectral features attributable to fundamental infrared vibrational modes of low-Ca carbonate are present in the Mini-TES spectra of Comanche outcrops. The average composition of Comanche carbonate approximates the average composition of the carbonate globules in Martian meteorite ALH 84001. Analogy with ALH 84001, terrestrial, and synthetic carbonate globules suggests that Comanche carbonate precipitated from aqueous solutions under hydrothermal conditions at near neutral pH in association with volcanic activity during the Noachian era. Comanche outcrop morphology suggests they are remnants of a larger carbonate-bearing formation that evolved in ultramafic rock and then preferentially eroded by a combination of aeolian

  11. The use of gelatine in long-term storage (up to 48 hr) at 5°C preserves the pre-freezing and post-thawing quality of brown bear sperm.

    PubMed

    Lopez-Urueña, E; Anel-López, L; Borragan, S; Ortega Ferrusola, C; Manrique, P; de Paz, P; Anel, L; Alvarez, M

    2016-10-01

    Sedimentation of spermatozoa occurs during long-term liquid storage and this may produce deleterious changes. Our aim was to apply gelatine supplementation during long-term pre-freezing storage of bear sperm, applying final dilution and 6% glycerol at room temperature and cool in straws. We tested four models of sperm storage using a 1:1 dilution in TTF-ULE-Bear extender (TesT-fructose-egg yolk-glycerol 6%): (i) second 1:1 dilution at room temperature (RT), cooling at 5°C in a tube and final dilution (100 × 10(6)  sperm ml(-1) ) (Standard); (ii) final dilution at RT and cooling in a tube (FD-Tube); (iii) final dilution at RT and cooling in 0.25 ml plastic straw (FD-Straw); and (iv) final dilution at RT in extender supplemented with 1.5% gelatine (Gelatine) and cooling in a 0.25 ml plastic straw. A Standard sample was stored at 5°C for 1 hr (Control); the rest of the samples (Standard, FD-Tube, FD-Straw, Gelatine) were stored for 24 or 48 hrs before freezing (100 × 10(6)  sperm ml(-1) , glycerol 6%). The quality of the samples was assessed for motility by CASA, and viability (SYBR-14/propidium iodide-PI-; VIAB), acrosomal status (PNA-FITC/PI; iACR) and apoptotic status (YO-PRO-1/PI; YOPRO-) by flow cytometry. At pre-freezing, after 48 hr, Gelatine showed significantly higher viability (for VIAB and YOPRO-) and progressiveness (PM, LIN and STR). At 48 hr, Gelatine showed similar YOPRO-, iACR, LIN, STR and ALH respect to Control. At both 24 and 48 h post-thawing, Gelatine sample had similar scores for YOPRO-, iACR, LIN, STR, WOB and VIAB (only 24 hr) when compared with Control, and lower for TM, PM, rapidPM, VAP and ALH. No differences were found among others experimental groups with respect to Control. In conclusion, gelatine could be a suitable alternative to preserve the viability and progressive motility of brown bear ejaculates during long-term pre-freezing storage at 5°C. © 2016 Blackwell Verlag GmbH.

  12. Al-26 from red giants. [connections with anomalous Mg-26 content in meteorites and solar system formation

    NASA Technical Reports Server (NTRS)

    Norgaard, H.

    1980-01-01

    Simplified models of thermally pulsing red giants are investigated, with particular emphasis on predicting the extent to which nuclear processing at the base of the convective envelope in conjunction with processing in the thermally unstable He shell can synthesize Al-26 (tau/1/2/ = 7.2 x 10 to the 5th yr). Values of Al-26/Al-27 of about 0.5-1, with Al-27/Al-27(solar) of about 1-2, are predicted in some cases. It is pointed out that such results can lead to isotope shifts in the absorption lines of AlH and AlO, which should be observationally identifiable in some late-type supergiants. The possible connection with the anomalous Mg-26 content (assigned to the decay of Al-26) detected in some meteorites and the connection with formation of the solar system are also touched on.

  13. Evidence for life in a martian meteorite?

    PubMed

    McSween, H Y

    1997-07-01

    The controversial hypothesis that the ALH84001 meteorite contains relics of ancient martian life has spurred new findings, but the question has not yet been resolved. Organic matter probably results, at least in part, from terrestrial contamination by Antarctic ice meltwater. The origin of nanophase magnetites and sulfides, suggested, on the basis of their sizes and morphologies, to be biogenic remains contested, as does the formation temperature of the carbonates that contain all of the cited evidence for life. The reported nonfossils may be magnetite whiskers and platelets, probably grown from a vapor. New observations, such as the possible presence of biofilms and shock metamorphic effects in the carbonates, have not yet been evaluated. Regardless of the ultimate conclusion, this controversy continues to help define strategies and sharpen tools that will be required for a Mars exploration program focused on the search for life.

  14. Extraterrestrial amino acids identified in metal-rich CH and CB carbonaceous chondrites from Antarctica

    NASA Astrophysics Data System (ADS)

    Burton, Aaron S.; Elsila, Jamie E.; Hein, Jason E.; Glavin, Daniel P.; Dworkin, Jason P.

    2013-03-01

    Carbonaceous chondrites contain numerous indigenous organic compounds and could have been an important source of prebiotic compounds required for the origin of life on Earth or elsewhere. Extraterrestrial amino acids have been reported in five of the eight groups of carbonaceous chondrites and are most abundant in CI, CM, and CR chondrites but are also present in the more thermally altered CV and CO chondrites. We report the abundance, distribution, and enantiomeric and isotopic compositions of simple primary amino acids in six metal-rich CH and CB carbonaceous chondrites that have not previously been investigated for amino acids: Allan Hills (ALH) 85085 (CH3), Pecora Escarpment (PCA) 91467 (CH3), Patuxent Range (PAT) 91546 (CH3), MacAlpine Hills (MAC) 02675 (CBb), Miller Range (MIL) 05082 (CB), and Miller Range (MIL) 07411 (CB). Amino acid abundances and carbon isotopic values were obtained by using both liquid chromatography time-of-flight mass spectrometry and fluorescence, and gas chromatography isotope ratio mass spectrometry. The δ13C/12C ratios of multiple amino acids fall outside of the terrestrial range and support their extraterrestrial origin. Extracts of CH chondrites were found to be particularly rich in amino acids (13-16 parts per million, ppm) while CB chondrite extracts had much lower abundances (0.2-2 ppm). The amino acid distributions of the CH and CB chondrites were distinct from the distributions observed in type 2 and 3 CM and CR chondrites and contained elevated levels of β-, γ-, and δ-amino acids compared to the corresponding α-amino acids, providing evidence that multiple amino acid formation mechanisms were important in CH and CB chondrites.

  15. Extraterrestrial Amino Acids Identified in Metal-Rich CH and CB Carbonaceous Chondrites from Antarctica

    NASA Technical Reports Server (NTRS)

    Burton, Aaron S.; Elsila, Jamie E.; Hein, Jason E.; Glavin, Daniel P.; Dworkin, Jason P.

    2013-01-01

    Carbonaceous chondrites contain numerous indigenous organic compounds and could have been an important source of prebiotic compounds required for the origin of life on Earth or elsewhere. Extraterrestrial amino acids have been reported in five of the eight groups of carbonaceous chondrites and are most abundant in CI, CM, and CR chondritesbut are also present in the more thermally altered CV and CO chondrites. We report the abundance, distribution, and enantiomeric and isotopic compositions of simple primary amino acids in six metal-rich CH and CB carbonaceous chondrites that have not previously been investigated for amino acids: Allan Hills (ALH) 85085 (CH3), Pecora Escarpment(PCA) 91467 (CH3), Patuxent Range (PAT) 91546 (CH3), MacAlpine Hills (MAC) 02675(CBb), Miller Range (MIL) 05082 (CB), and Miller Range (MIL) 07411 (CB). Amino acid abundances and carbon isotopic values were obtained by using both liquid chromatography time-of-flight mass spectrometry and fluorescence, and gas chromatography isotope ratiomass spectrometry. The (delta D, delta C-13, delta N-15) ratios of multiple amino acids fall outside of the terrestrial range and support their extraterrestrial origin. Extracts of CH chondrites were found to be particularly rich in amino acids (1316 parts per million, ppm) while CB chondrite extracts had much lower abundances (0.22 ppm). The amino acid distributions of the CH and CB chondrites were distinct from the distributions observed in type 2 and 3 CM and CR chondrites and contained elevated levels of beta-, gamma-, and delta-amino acids compared to the corresponding alpha-amino acids, providing evidence that multiple amino acid formation mechanisms were important in CH and CB chondrites.

  16. Distribution of Aliphatic Amines in CO, CV, and CK Carbonaceous Chondrites and Relation to Mineralogy and Processing History

    NASA Technical Reports Server (NTRS)

    Aponte, Jose C.; Abreu, Neyda M.; Glavin, Daniel P.; Dworkin, Jason P.; Elsila, Jamie E.

    2017-01-01

    The analysis of water-soluble organic compounds in meteorites provides valuable insights into the prebiotic synthesis of organic matter and the processes that occurred during the formation of the solar system. We investigated the concentration of aliphatic monoamines present in hot acid water extracts of the unaltered Antarctic carbonaceous chondrites, Dominion Range (DOM) 08006 (CO3) and Miller Range (MIL) 05013 (CO3), and the thermally altered meteorites, Allende (CV3), LAP 02206 (CV3), GRA 06101 (CV3), Allan Hills (ALH) 85002 (CK4), and EET 92002 (CK5). We have also reviewed and assessed the petrologic characteristics of the meteorites studied here to evaluate the effects of asteroidal processing on the abundance and molecular distributions of monoamines. The CO3, CV3, CK4, and CK5 meteorites studied here contain total concentrations of amines ranging from 1.2 to 4.0 nmol/g of meteorite; these amounts are 1-3 orders of magnitude below those observed in carbonaceous chondrites from the CI, CM, and CR groups. The low-amine abundances for CV and CK chondrites may be related to their extensive degree of thermal metamorphism and/or to their low original amine content. Although the CO3 meteorites, DOM 08006 and MIL 05013, do not show signs of thermal and aqueous alteration, their monoamine contents are comparable to those observed in moderately/extensively thermally altered CV3, CK4, and CK5 carbonaceous chondrites. The low content of monoamines in pristine CO carbonaceous chondrites suggests that the initial amounts, and not asteroidal processes, play a dominant role in the content of monoamines in carbonaceous chondrites. The primary monoamines, methylamine, ethylamine, and n-propylamine constitute the most abundant amines in the CO3, CV3, CK4, and CK5 meteorites studied here. Contrary to the predominance of n-x-amino acid isomers in CO3 and thermally altered meteorites, there appears to be no preference for the larger n-amines.

  17. Fluids During Diagenesis and Sulfate Vein Formation in Sediments at Gale Crater, Mars

    NASA Technical Reports Server (NTRS)

    Schwenzer, S. P.; Bridges, J. C.; Weins, R. C.; Conrad, P. G.; Kelley, S. P.; Leveille, R.; Mangold, N.; Martin-Torres, J.; McAdam, A.; Newsom, H.; hide

    2016-01-01

    We model the fluids involved in the alteration processes recorded in the Sheep bed Member mudstones of Yellowknife Bay (YKB), Gale crater, Mars, as revealed by the Mars Science Laboratory Curiosity rover investigations. We compare the Gale crater waters with fluids modeled for shergottites, nakhlites, and the ancient meteorite ALH 84001, as well as rocks analyzed by the Mars Exploration rovers, and with terrestrial ground and surface waters. The aqueous solution present during sediment alteration associated with phyllosilicate formation at Gale was high in Na, K, and Si; had low Mg, Fe, and Al concentrations relative to terrestrial ground waters such as the Deccan Traps and other modeled Mars fluids; and had near neutral to alkaline pH. Ca and S species were present in the 10(exp -3) to 10(exp -2) concentration range. A fluid local to Gale crater strata produced the alteration products observed by Curiosity and subsequent evaporation of this ground water- type fluid formed impure sulfate- and silica-rich deposits veins or horizons. In a second, separate stage of alteration, partial dissolution of this sulfate-rich layer in Yellowknife Bay,or beyond, led to the pure sulfate veins observed in YKB. This scenario is analogous to similar processes identified at a terrestrial site in Triassic sediments with gypsum veins of the Mercia Mudstone Group in Watchet Bay, UK.

  18. Reactions of aqueous aluminum species at mineral surfaces

    USGS Publications Warehouse

    Brown, David Wayne; Hem, John David

    1975-01-01

    Aqueous aluminum solutions containing 4.5 ? 10 4 molar aluminum in 0.01 molar NaC104 were partly neutralized with NaOH to give OH:A1 mole ratios from 1.40 to 2.76. Measured amounts of montmorillonite, kaolinite, volcanic ash, or feldspathic sand were added to provide an area of inert surface. Reactions that occurred during 100 days of aging were compared with those in similar solutions without added surfaces, studied in earlier work. Adsorption of monomeric species Al(H20)6+3, AlOH(H2O)5+2, and Al(OH)2(H2O 4? on the added surfaces follows a cation exchange mass law equilibrium model, and adsorption is essentially complete in 1 hour. Only minor changes in monomeric aluminum species occurred after that. Rapid adsorption of polynuclear aluminum hydroxide species also occurs and follows the pattern of the Langmuir adsorption isotherm. In the absence of surfaces, the polynuclear ions slowly increase in size and become microcrystalline gibbsite during aging. Electron micrographs showed microcrystalline gibbsite was present or surfaces after aging only 2 days. However, the analytical data suggest this material must have been adsorbed after it had already attained a near-crystalline state. Adsorbed polynuclear aluminum hydroxide species were not extensively converted to microcrystalline gibbsite during 100 days of aging.

  19. Fluids during diagenesis and sulfate vein formation in sediments at Gale crater, Mars

    NASA Astrophysics Data System (ADS)

    Schwenzer, S. P.; Bridges, J. C.; Wiens, R. C.; Conrad, P. G.; Kelley, S. P.; Leveille, R.; Mangold, N.; Martín-Torres, J.; McAdam, A.; Newsom, H.; Zorzano, M. P.; Rapin, W.; Spray, J.; Treiman, A. H.; Westall, F.; Fairén, A. G.; Meslin, P.-Y.

    2016-11-01

    We model the fluids involved in the alteration processes recorded in the Sheepbed Member mudstones of Yellowknife Bay (YKB), Gale crater, Mars, as revealed by the Mars Science Laboratory Curiosity rover investigations. We compare the Gale crater waters with fluids modeled for shergottites, nakhlites, and the ancient meteorite ALH 84001, as well as rocks analyzed by the Mars Exploration rovers, and with terrestrial ground and surface waters. The aqueous solution present during sediment alteration associated with phyllosilicate formation at Gale was high in Na, K, and Si; had low Mg, Fe, and Al concentrations—relative to terrestrial groundwaters such as the Deccan Traps and other modeled Mars fluids; and had near neutral to alkaline pH. Ca and S species were present in the 10-3 to 10-2 concentration range. A fluid local to Gale crater strata produced the alteration products observed by Curiosity and subsequent evaporation of this groundwater-type fluid formed impure sulfate- and silica-rich deposits—veins or horizons. In a second, separate stage of alteration, partial dissolution of this sulfate-rich layer in Yellowknife Bay, or beyond, led to the pure sulfate veins observed in YKB. This scenario is analogous to similar processes identified at a terrestrial site in Triassic sediments with gypsum veins of the Mercia Mudstone Group in Watchet Bay, UK.

  20. Genesis of Augite-Bearing Ureilites: Evidence From LA-ICP-MS Analyses of Pyroxenes and Olivine

    NASA Technical Reports Server (NTRS)

    Herrin, J. S.; Lee, C-T. A.; Mittlefehldt, D. W.

    2008-01-01

    Ureilites are ultramafic achondrites composed primarily of coarse-grained low-Ca pyroxene and olivine with interstitial carbonaceous material, but a number of them contain augite [1]. Ureilites are considered to be restites after partial melting of a chondritic precursor, although at least some augite-bearing ureilites may be partially cumulate [1, 2]. In this scenario, the augite is a cumulus phase derived from a melt that infiltrated a restite composed of typical ureilite material (olivine+low-Ca pyroxene) [2]. To test this hypothesis, we examined the major and trace element compositions of silicate minerals in select augite-bearing ureilites with differing mg#. Polished thick sections of the augite-bearing ureilites ALH 84136 , EET 87511, EET 96293, LEW 88201, and META78008 and augite-free typical ureilite EET 90019 were examined by EPMA for major and minor elements and laser ablation ICP-MS (LA-ICP-MS) for trace elements, REE in particular. Although EET 87511 is reported to contain augite, the polished section that we obtained did not.

  1. Isotope ratios of H, C, and O in CO2 and H2O of the martian atmosphere.

    PubMed

    Webster, Chris R; Mahaffy, Paul R; Flesch, Gregory J; Niles, Paul B; Jones, John H; Leshin, Laurie A; Atreya, Sushil K; Stern, Jennifer C; Christensen, Lance E; Owen, Tobias; Franz, Heather; Pepin, Robert O; Steele, Andrew; Achilles, Cherie; Agard, Christophe; Alves Verdasca, José Alexandre; Anderson, Robert; Anderson, Ryan; Archer, Doug; Armiens-Aparicio, Carlos; Arvidson, Ray; Atlaskin, Evgeny; Aubrey, Andrew; Baker, Burt; Baker, Michael; Balic-Zunic, Tonci; Baratoux, David; Baroukh, Julien; Barraclough, Bruce; Bean, Keri; Beegle, Luther; Behar, Alberto; Bell, James; Bender, Steve; Benna, Mehdi; Bentz, Jennifer; Berger, Gilles; Berger, Jeff; Berman, Daniel; Bish, David; Blake, David F; Blanco Avalos, Juan J; Blaney, Diana; Blank, Jen; Blau, Hannah; Bleacher, Lora; Boehm, Eckart; Botta, Oliver; Böttcher, Stephan; Boucher, Thomas; Bower, Hannah; Boyd, Nick; Boynton, Bill; Breves, Elly; Bridges, John; Bridges, Nathan; Brinckerhoff, William; Brinza, David; Bristow, Thomas; Brunet, Claude; Brunner, Anna; Brunner, Will; Buch, Arnaud; Bullock, Mark; Burmeister, Sönke; Cabane, Michel; Calef, Fred; Cameron, James; Campbell, John; Cantor, Bruce; Caplinger, Michael; Caride Rodríguez, Javier; Carmosino, Marco; Carrasco Blázquez, Isaías; Charpentier, Antoine; Chipera, Steve; Choi, David; Clark, Benton; Clegg, Sam; Cleghorn, Timothy; Cloutis, Ed; Cody, George; Coll, Patrice; Conrad, Pamela; Coscia, David; Cousin, Agnès; Cremers, David; Crisp, Joy; Cros, Alain; Cucinotta, Frank; d'Uston, Claude; Davis, Scott; Day, Mackenzie; de la Torre Juarez, Manuel; DeFlores, Lauren; DeLapp, Dorothea; DeMarines, Julia; DesMarais, David; Dietrich, William; Dingler, Robert; Donny, Christophe; Downs, Bob; Drake, Darrell; Dromart, Gilles; Dupont, Audrey; Duston, Brian; Dworkin, Jason; Dyar, M Darby; Edgar, Lauren; Edgett, Kenneth; Edwards, Christopher; Edwards, Laurence; Ehlmann, Bethany; Ehresmann, Bent; Eigenbrode, Jen; Elliott, Beverley; Elliott, Harvey; Ewing, Ryan; Fabre, Cécile; Fairén, Alberto; Farley, Ken; Farmer, Jack; Fassett, Caleb; Favot, Laurent; Fay, Donald; Fedosov, Fedor; Feldman, Jason; Feldman, Sabrina; Fisk, Marty; Fitzgibbon, Mike; Floyd, Melissa; Flückiger, Lorenzo; Forni, Olivier; Fraeman, Abby; Francis, Raymond; François, Pascaline; Freissinet, Caroline; French, Katherine Louise; Frydenvang, Jens; Gaboriaud, Alain; Gailhanou, Marc; Garvin, James; Gasnault, Olivier; Geffroy, Claude; Gellert, Ralf; Genzer, Maria; Glavin, Daniel; Godber, Austin; Goesmann, Fred; Goetz, Walter; Golovin, Dmitry; Gómez Gómez, Felipe; Gómez-Elvira, Javier; Gondet, Brigitte; Gordon, Suzanne; Gorevan, Stephen; Grant, John; Griffes, Jennifer; Grinspoon, David; Grotzinger, John; Guillemot, Philippe; Guo, Jingnan; Gupta, Sanjeev; Guzewich, Scott; Haberle, Robert; Halleaux, Douglas; Hallet, Bernard; Hamilton, Vicky; Hardgrove, Craig; Harker, David; Harpold, Daniel; Harri, Ari-Matti; Harshman, Karl; Hassler, Donald; Haukka, Harri; Hayes, Alex; Herkenhoff, Ken; Herrera, Paul; Hettrich, Sebastian; Heydari, Ezat; Hipkin, Victoria; Hoehler, Tori; Hollingsworth, Jeff; Hudgins, Judy; Huntress, Wesley; Hurowitz, Joel; Hviid, Stubbe; Iagnemma, Karl; Indyk, Steve; Israël, Guy; Jackson, Ryan; Jacob, Samantha; Jakosky, Bruce; Jensen, Elsa; Jensen, Jaqueline Kløvgaard; Johnson, Jeffrey; Johnson, Micah; Johnstone, Steve; Jones, Andrea; Joseph, Jonathan; Jun, Insoo; Kah, Linda; Kahanpää, Henrik; Kahre, Melinda; Karpushkina, Natalya; Kasprzak, Wayne; Kauhanen, Janne; Keely, Leslie; Kemppinen, Osku; Keymeulen, Didier; Kim, Myung-Hee; Kinch, Kjartan; King, Penny; Kirkland, Laurel; Kocurek, Gary; Koefoed, Asmus; Köhler, Jan; Kortmann, Onno; Kozyrev, Alexander; Krezoski, Jill; Krysak, Daniel; Kuzmin, Ruslan; Lacour, Jean Luc; Lafaille, Vivian; Langevin, Yves; Lanza, Nina; Lasue, Jeremie; Le Mouélic, Stéphane; Lee, Ella Mae; Lee, Qiu-Mei; Lees, David; Lefavor, Matthew; Lemmon, Mark; Lepinette Malvitte, Alain; Léveillé, Richard; Lewin-Carpintier, Éric; Lewis, Kevin; Li, Shuai; Lipkaman, Leslie; Little, Cynthia; Litvak, Maxim; Lorigny, Eric; Lugmair, Guenter; Lundberg, Angela; Lyness, Eric; Madsen, Morten; Maki, Justin; Malakhov, Alexey; Malespin, Charles; Malin, Michael; Mangold, Nicolas; Manhes, Gérard; Manning, Heidi; Marchand, Geneviève; Marín Jiménez, Mercedes; Martín García, César; Martin, Dave; Martin, Mildred; Martínez-Frías, Jesús; Martín-Soler, Javier; Martín-Torres, F Javier; Mauchien, Patrick; Maurice, Sylvestre; McAdam, Amy; McCartney, Elaina; McConnochie, Timothy; McCullough, Emily; McEwan, Ian; McKay, Christopher; McLennan, Scott; McNair, Sean; Melikechi, Noureddine; Meslin, Pierre-Yves; Meyer, Michael; Mezzacappa, Alissa; Miller, Hayden; Miller, Kristen; Milliken, Ralph; Ming, Douglas; Minitti, Michelle; Mischna, Michael; Mitrofanov, Igor; Moersch, Jeff; Mokrousov, Maxim; Molina Jurado, Antonio; Moores, John; Mora-Sotomayor, Luis; Morookian, John Michael; Morris, Richard; Morrison, Shaunna; Mueller-Mellin, Reinhold; Muller, Jan-Peter; Muñoz Caro, Guillermo; Nachon, Marion; Navarro López, Sara; Navarro-González, Rafael; Nealson, Kenneth; Nefian, Ara; Nelson, Tony; Newcombe, Megan; Newman, Claire; Newsom, Horton; Nikiforov, Sergey; Nixon, Brian; Noe Dobrea, Eldar; Nolan, Thomas; Oehler, Dorothy; Ollila, Ann; Olson, Timothy; de Pablo Hernández, Miguel Ángel; Paillet, Alexis; Pallier, Etienne; Palucis, Marisa; Parker, Timothy; Parot, Yann; Patel, Kiran; Paton, Mark; Paulsen, Gale; Pavlov, Alex; Pavri, Betina; Peinado-González, Verónica; Peret, Laurent; Perez, Rene; Perrett, Glynis; Peterson, Joe; Pilorget, Cedric; Pinet, Patrick; Pla-García, Jorge; Plante, Ianik; Poitrasson, Franck; Polkko, Jouni; Popa, Radu; Posiolova, Liliya; Posner, Arik; Pradler, Irina; Prats, Benito; Prokhorov, Vasily; Purdy, Sharon Wilson; Raaen, Eric; Radziemski, Leon; Rafkin, Scot; Ramos, Miguel; Rampe, Elizabeth; Raulin, François; Ravine, Michael; Reitz, Günther; Rennó, Nilton; Rice, Melissa; Richardson, Mark; Robert, François; Robertson, Kevin; Rodriguez Manfredi, José Antonio; Romeral-Planelló, Julio J; Rowland, Scott; Rubin, David; Saccoccio, Muriel; Salamon, Andrew; Sandoval, Jennifer; Sanin, Anton; Sans Fuentes, Sara Alejandra; Saper, Lee; Sarrazin, Philippe; Sautter, Violaine; Savijärvi, Hannu; Schieber, Juergen; Schmidt, Mariek; Schmidt, Walter; Scholes, Daniel; Schoppers, Marcel; Schröder, Susanne; Schwenzer, Susanne; Sebastian Martinez, Eduardo; Sengstacken, Aaron; Shterts, Ruslan; Siebach, Kirsten; Siili, Tero; Simmonds, Jeff; Sirven, Jean-Baptiste; Slavney, Susie; Sletten, Ronald; Smith, Michael; Sobrón Sánchez, Pablo; Spanovich, Nicole; Spray, John; Squyres, Steven; Stack, Katie; Stalport, Fabien; Stein, Thomas; Stewart, Noel; Stipp, Susan Louise Svane; Stoiber, Kevin; Stolper, Ed; Sucharski, Bob; Sullivan, Rob; Summons, Roger; Sumner, Dawn; Sun, Vivian; Supulver, Kimberley; Sutter, Brad; Szopa, Cyril; Tan, Florence; Tate, Christopher; Teinturier, Samuel; ten Kate, Inge; Thomas, Peter; Thompson, Lucy; Tokar, Robert; Toplis, Mike; Torres Redondo, Josefina; Trainer, Melissa; Treiman, Allan; Tretyakov, Vladislav; Urqui-O'Callaghan, Roser; Van Beek, Jason; Van Beek, Tessa; VanBommel, Scott; Vaniman, David; Varenikov, Alexey; Vasavada, Ashwin; Vasconcelos, Paulo; Vicenzi, Edward; Vostrukhin, Andrey; Voytek, Mary; Wadhwa, Meenakshi; Ward, Jennifer; Weigle, Eddie; Wellington, Danika; Westall, Frances; Wiens, Roger Craig; Wilhelm, Mary Beth; Williams, Amy; Williams, Joshua; Williams, Rebecca; Williams, Richard B; Wilson, Mike; Wimmer-Schweingruber, Robert; Wolff, Mike; Wong, Mike; Wray, James; Wu, Megan; Yana, Charles; Yen, Albert; Yingst, Aileen; Zeitlin, Cary; Zimdar, Robert; Zorzano Mier, María-Paz

    2013-07-19

    Stable isotope ratios of H, C, and O are powerful indicators of a wide variety of planetary geophysical processes, and for Mars they reveal the record of loss of its atmosphere and subsequent interactions with its surface such as carbonate formation. We report in situ measurements of the isotopic ratios of D/H and (18)O/(16)O in water and (13)C/(12)C, (18)O/(16)O, (17)O/(16)O, and (13)C(18)O/(12)C(16)O in carbon dioxide, made in the martian atmosphere at Gale Crater from the Curiosity rover using the Sample Analysis at Mars (SAM)'s tunable laser spectrometer (TLS). Comparison between our measurements in the modern atmosphere and those of martian meteorites such as ALH 84001 implies that the martian reservoirs of CO2 and H2O were largely established ~4 billion years ago, but that atmospheric loss or surface interaction may be still ongoing.

  2. Element distributions in metallic fractions of ordinary chondrites

    NASA Astrophysics Data System (ADS)

    Kong, P.; Ebihara, M.; Endo, K.

    1994-07-01

    Kamacite and taenite are the major metallic phases in ordinary chondrite, in individual grains of pure alloy. Wood interpreted the concentration gradients of Ni found in two metal phases as a result of exsolution of kamacite from taenite followed by sluggish diffusion of Ni into the taenite crystals upon cooling through approximately 500 C. A selective chemical dissolution method was developed to separated taenite from kamacite and this method was applied to several ordinary chondrites. Based on Instrumental Neutron Activation Analysis (INAA) data and Mossbauer spectra for the metal separates, we evaluated the distribution of various elements between taenite and kamacite. The magnetic fraction separated from ALH 77231 (L6) was boiled in HF for 2 min and named M-1. The M-1 fraction was further treated for 5, 10, and 15 min and the remaining fractions were designed as M-2, M-3, and M-4 respectively. Mossbauer spectrum showed that M-1 was composed almost of alpha-phase kamacite. Mossbauer spectra of the M-2, M-3, and M-4 showed each having similar intensities of kamacite, taenite, and tetrataenite. On the basis of different leaching rate with concentrated HF acid between kamacite and taenite, we can determine element distributions in these different fractions. INAA analyses show that the M-1 is composed of 10% Ni. Contents of Ni in the M-2, M-3, and M-4 show that these three metal fractions are mainly composed of Ni-rich metals with a mean value of 36% Ni. Based on different proportions of kamacite and taenite in these metal fractions, we calculated siderophile-element contents in taenite and kamacite.

  3. The classification and complex thermal history of the enstatite chondrites

    NASA Technical Reports Server (NTRS)

    Zhang, Yanhong; Benoit, Paul H.; Sears, Derek W. G.

    1995-01-01

    We have carried out instrumental neutron activation analysis of 11 enstatite chondrites and electron microprobe analyses of 17 enstatite chondrites, most of which were previously little described. We report here the third known EH5 chondrite (LEW 88180) and an unusual EL6 chondrite (LEW 87119), new data on four EL3 chondrites (ALH 85119, EET 90299, PCA 91020, and MAC 88136, which is paired with MAC 88180 and MAC 88184), the second EL5 chondrite (TIL 91714), and an unusual metal-rich and sulfide-poor EL3 chondrite (LEW 87223). The often discussed differences in mineral composition displayed by the EH and EL chondrites are not as marked after the inclusion of the new samples in the database, and the two classes apparently experienced a similar range of equilibrium temperatures. However, texturally the EL chondrites appear to have experienced much higher levels of metamorphic alteration than EH chondrites of similar equilibration temperatures. Most of the petrologic type criteria are not applicable to enstatite chondrites and, unlike the ordinary chondrites, texture and mineralogy reflect different aspects of the meteorite history. We therefore propose that the existing petrologic type scheme not be used for enstatite chondrites. We suggest that while 'textural type' reflects peak metamorphic temperatures, the 'mineralogical type' reflects equilibration during postmetamorphic (probably regolith) processes. Unlike the ordinary chondrites and EH chondrites, EL chondrites experienced an extensive low-temperature metamorphic episode. There are now a large number of enstatite meteorite breccias and impact melts, and apparently surface processes were important in determining the present nature of the enstatite chondrites.

  4. Organic Carbon Exists in Mars Meteorites: where is it on the Martian Surface?

    NASA Astrophysics Data System (ADS)

    McKay, David; Clemett, Simon; Gibson, Everett; Thomas-Keprta, Kathie; Wentworth, Susan

    The search for organic carbon on Mars has been a major challenge. The first attempt was the Viking GC-MS in situ experiment which gave inconclusive results at two sites on Mars [1]. After the discovery that the SNC meteorites were from Mars [2], [3-5] reported C isotopic compositional information which suggested a reduced C component present in the Martian meteorites. [6 7] reported the presence of reduced C components (i.e., polycyclic aromatic hydrocarbons) associated with the carbonate globules in ALH84001. Jull et al. [8] noted in Nakhla there was an acid insoluble C component present with more than 75% of its C lacking any 14 C, which is modern-day terrestrial carbon. This C fraction was believed to be either indigenous martian or ancient meteoritic carbon. Fisk et al. [9, 10] have shown textural evidence along with C-enriched areas within fractures in Nakhla and ALH84001. Westall et al. [11] have shown the presence of a large irregular fragment of organic material completely embedded within a chip of ALH84001. Interior samples from the Nakhla SNC made available by the British Museum of Natural His-tory, were analyzed. Petrographic examination [12] of Nakhla showed evidence of fractures ( 0.5 m wide) filled with dark brown to black dendritic material with characteristics similar to those observed by [10]. Iddingsite is also present along fractures in olivine. Fracture filling and dendritic material was examined by SEM-EDX, TEM-EDX, Focused Electron Beam mi-croscopy, Laser Raman Spectroscopy, Nano-SIMS Ion Micro-probe, and Stepped-Combustion Static Mass Spectrometry. Observations from the first three techniques are discussed in [12 and 13]. Nano-SIMS Ion Microprobe studies of the C-bearing fractures, containing the optically dark dendritic material, show direct correlation between C- and CN- abundances. Ion abun-dances for epoxy are distinct from those of the dendritic material[12] . Laser Raman Spectrometry was utilized to examine the optically dark dendritic

  5. Facile Preparation of Ultrafine Aluminum Hydroxide Particles with or without Mesoporous MCM-41 in Ambient Environments.

    PubMed

    Dubovoy, Viktor; Subramanyam, Ravi; Stranick, Michael; Du-Thumm, Laurence; Pan, Long

    2017-05-11

    An aqueous suspension of nanogibbsite was synthesized via the titration of aluminum aqua acid [Al(H2O)6] 3+ with L-arginine to pH 4.6. Since the hydrolysis of aqueous aluminum salts is known to produce a wide array of products with a wide range of size distributions, a variety of state-of-the-art instruments (i.e., 27 Al/ 1 H NMR, FTIR, ICP-OES, TEM-EDX, XPS, XRD, and BET) were used to characterize the synthesis products and identification of byproducts. The product, which was comprised of nanoparticles (10-30 nm), was isolated using gel permeation chromatography (GPC) column technique. Fourier transform infrared (FTIR) spectroscopy and powder X-ray diffraction (PXRD) identified the purified material as the gibbsite polymorph of aluminum hydroxide. The addition of inorganic salts (e.g., NaCl) induced electrostatic destabilization of the suspension, thereby agglomerating the nanoparticles to yield Al(OH)3 precipitate with large particle sizes. By utilizing the novel synthetic method described here, Al(OH)3 was partially loaded inside the highly ordered mesoporous framework of MCM-41, with average pore dimensions of 2.7 nm, producing an aluminosilicate material with both octahedral and tetrahedral Al (Oh/Td = 1.4). The total Al content, measured using energy-dispersive X-ray spectrometry (EDX), was 11% w/w with a Si/Al molar ratio of 2.9. A comparison of bulk EDX with surface X-ray photoelectron spectroscopy (XPS) elemental analysis provided insight into the distribution of Al within the aluminosilicate material. Furthermore, a higher ratio of Si/Al was observed on the external surface (3.6) as compared to the bulk (2.9). Approximations of O/Al ratios suggest a higher concentration of Al(O)3 and Al(O)4 groups near the core and external surface, respectively. The newly developed synthesis of Al-MCM-41 yields a relatively high Al content while maintaining the integrity of the ordered silica framework and can be used for applications where hydrated or anhydrous Al2O3

  6. Field Characterization of the Mineralogy and Organic Chemistry of Carbonates from the 2010 Arctic Mars Analog Svalbard Expedition by Evolved Gas Analysis

    NASA Technical Reports Server (NTRS)

    McAdam, A. C.; Ten Kate, I. L.; Stern, J. C.; Mahaffy, P. R.; Blake, D. F.; Morris, R. V.; Steele, A.; Amundson, H. E. F.

    2011-01-01

    The 2010 Arctic Mars Analog Svalbard Expedition (AMASE) investigated two geologic settings using methodologies and techniques being developed or considered for future Mars missions, such as the Mars Science Laboratory (MSL), ExoMars, and Mars Sample Return. The Sample Analysis at Mars (SAM) [1] instrument suite, which will be on MSL, consists of a quadrupole mass spectrometer (QMS), a gas chromatograph (GC), and a tunable laser mass spectrometer (TLS); all will be applied to analyze gases created by pyrolysis of samples. During AMASE, a Hiden Evolved Gas Analysis-Mass Spectrometer (EGA-MS) system represented the EGA-MS capability of SAM. Another MSL instrument, CheMin, will use x-ray diffraction (XRD) and x-ray fluorescence (XRF) to perform quantitative mineralogical characterization of samples [e.g., 2]. Field-portable versions of CheMin were used during AMASE. AMASE 2010 focused on two sites that represented biotic and abiotic analogs. The abiotic site was the basaltic Sigurdfjell vent complex, which contains Mars-analog carbonate cements including carbonate globules which are excellent analogs for the globules in the ALH84001 martian meteorite [e.g., 3, 4]. The biotic site was the Knorringfjell fossil methane seep, which featured carbonates precipitated in a methane-supported chemosynthetic community [5]. This contribution focuses on EGA-MS analyses of samples from each site, with mineralogy comparisons to CheMin team results. The results give insight into organic content and organic-mineral associations, as well as some constraints on the minerals present.

  7. Isotopic analysis of individual refractory metal nuggets using atom probe tomography

    NASA Astrophysics Data System (ADS)

    Daly, L.; Bland, P.; Schaefer, B. F.; Saxey, D. W.; Reddy, S.; Fougerouse, D.; William, R. D. A.; Forman, L. V.; Trimby, P.; La Fontaine, A.; Yang, L.; Cairney, J.; Ringer, S.

    2016-12-01

    Sub-micrometre metallic alloys of the highly siderophile elements, known as refractory metal nuggets (RMNs), can be found in primitive carbonaceous chondrites. There has been some suggestion that these grains may have a pre-solar origin, however their <1 µm size has meant that isotopic analysis of individual grains has not previously been possible. Atom probe microscopy has sufficient spatial resolution to quantify the isotopic compositions, across the entire mass range, of small sample volumes (<0.02 µm3) with high sensitivity and precision. We present analyses of four individual RMNs from the same refractory inclusion within the ALH 77307 meteorite. The results indicate that these RMNs have significant isotopic deviations from solar relative isotope abundances and therefore preserve a pre-solar isotopic signature. All RMNs exhibit large p-process enrichments in 98Ru and depletions in s-process 186Os. Two RMNs have a similar isotopic signature, suggesting formation in the same stellar environment. This similarity between two RMNs indicates that there may be a significant contribution of material to our solar system from a single source. The other two RMNs are isotopically dissimilar. Finally, three of the RMNs plot on a 187Re -187Os isochron from which we can derive a galactic age of 12.5 Ga ±1.8. To the best of our knowledge this is the first direct determination of the age of the Milky Way through physical analysis of non-solar material.

  8. Computer-assisted sperm analysis of fresh epididymal cat spermatozoa and the impact of cool storage (4 degrees C) on sperm quality.

    PubMed

    Filliers, M; Rijsselaere, T; Bossaert, P; De Causmaecker, V; Dewulf, J; Pope, C E; Van Soom, A

    2008-12-01

    Epididymal cat sperm is commonly used for in vitro fertilization. Because of the high variability in preparation protocols and methods of evaluation, sperm quality may vary considerably between experiments and laboratories. The aims of the present study were (1) to describe an epididymal sperm preparation protocol to produce clean, highly motile samples using density gradient centrifugation, (2) to provide reference values of computer-assisted semen analysis (CASA) parameters of fresh epididymal cat sperm after density gradient centrifugation and (3) to investigate the effect of cool storage on various spermatozoa characteristics. After slicing the epididymides, viable and motile sperm cells were isolated using Percoll centrifugation. Sperm motility parameters were subsequently assessed using CASA in experiment 1. In experiment 2, fresh (day 0) sperm samples were evaluated for motility parameters (HTR) and stained for assessment of acrosomal status (FITC-PSA), morphology (eosin/nigrosin (E/N)), membrane integrity (E/N and SYBR((R))14-PI) and DNA fragmentation (TUNEL). After addition of a Tris-glucose-citrate diluent containing 20% egg yolk, samples were cooled to 4 degrees C and reassessed on d1, d3, d5, d7 and d10. Cool storage impaired most motility and velocity parameters: MOT, PMOT, VAP, VSL, VCL, BCF, RAPID and the percentage of normal spermatozoa showed a decrease over time (P<0.05) as compared to fresh samples. In contrast, STR, ALH, membrane integrity, DNA fragmentation and the percentage of acrosome intact spermatozoa were not affected by cool storage. However, the influence of cool storage of cat spermatozoa on subsequent in vitro embryo development and quality after IVF requires further investigation.

  9. Mars Atmospheric Composition, Isotope Ratios and Seasonal Variations: Overview and Updates of the SAM Measurements at Gale Crater

    NASA Technical Reports Server (NTRS)

    Niles, Paul

    2014-01-01

    We will summarize the in situ measurements of atmospheric composition and the isotopic ratios of D/H in water, C-13/C-12, O-18/O-16, O-17 / O-16, and C-13 O-18 / C-12 O-16 in carbon dioxide, and Ar-38 / Ar-36, Kr-x / Kr-84, and N-15 / N-14 made in the martian atmosphere at Gale Crater from the Curiosity Rover using the Sample Analysis at Mars (SAM)'s Quadrupole Mass Spectrometer (QMS) and Tunable Laser Spectrometer (TLS). With data over 700 sols since the Curiosity landing, we will discuss evidence and implications for changes on seasonal and other timescales. We will also present results for continued methane and methane enrichment experiments over this time period. Comparison between our measurements in the modern atmosphere and those of martian meteorites like ALH 84001 implies that the martian reservoirs of CO2 and H2O were largely established approximately 4 billion years ago, but that atmospheric loss or surface interaction may be still ongoing.

  10. Astrobiology Objectives for Mars Sample Return

    NASA Astrophysics Data System (ADS)

    Meyer, M. A.

    2002-05-01

    Astrobiology is the study of life in the Universe, and a major objective is to understand the past, present, and future biologic potential of Mars. The current Mars Exploration Program encompasses a series of missions for reconnaissance and in-situ analyses to define in time and space the degree of habitability on Mars. Determining whether life ever existed on Mars is a more demanding question as evidenced by controversies concerning the biogenicity of features in the Mars meteorite ALH84001 and in the earliest rocks on Earth. In-situ studies may find samples of extreme interest but resolution of the life question most probably would require a sample returned to Earth. A selected sample from Mars has the many advantages: State-of-the-art instruments, precision sample handling and processing, scrutiny by different investigators employing different techniques, and adaptation of approach to any surprises It is with a returned sample from Mars that Astrobiology has the most to gain in determining whether life did, does, or could exist on Mars.

  11. Using Vanadium in Spinel as a Sensor of Oxygen Fugacity in Meteorites: Applications to Mars, Vesta, and Other Asteroids

    NASA Technical Reports Server (NTRS)

    Righter, K.; Sutton, S.; Danielson, L.; Le, L.; Newville, M.; Pando, K.

    2009-01-01

    Igneous and metamorphic rocks commonly contain a mineral assemblage that allows oxygen fugacity to be calculated or constrained such as FeTi oxides, olivine-opx-spinel, or some other oxybarometer [1]. Some rocks, however, contain a limited mineral assemblage and do not provide constraints on fO2 using mineral equilibria. Good examples of the latter are orthopyroxenites or dunites, such as diogenites, ALH 84001, chassignites, or brachinites. In fact it is no surprise that the fO2 of many of these samples is not well known, other than being "reduced" and below the metal saturation value. In order to bridge this gap in our understanding, we have initiated a study of V in chromites in natural meteorite samples. Because the V pre-edge peak intensity and energy in chromites varies with fO2 (Fig. 1) [2], and this has been calibrated over a large fO 2 range, we can apply this relation to rocks for which we otherwise have no fO2 constraints.

  12. ESEEM of industrial quartz powders: insights into crystal chemistry of Al defects

    NASA Astrophysics Data System (ADS)

    Romanelli, Maurizio; Di Benedetto, Francesco; Bartali, Laura; Innocenti, Massimo; Fornaciai, Gabriele; Montegrossi, Giordano; Pardi, Luca A.; Zoleo, Alfonso; Capacci, Fabio

    2012-06-01

    A set of raw industrial materials, that is, pure quartz and quartz-rich mixtures, were investigated through electron paramagnetic resonance and electron spin echo-envelope modulation spectroscopies, with the aim of evaluating the effective role played by defect centres and of assessing whether they can be used to monitor changes in the physical properties of quartz powders with reference to their health effects. The obtained results point to two interactions of the Al defect centres with H+, hosted in sites within the channels parallel and perpendicular to the c axis of quartz, respectively. These two Al/H+ (hAl) centres exhibit a weak chemical bond, and their relative amounts appear to be modified/controlled by the thermo-mechanical processes underwent by powders. Indeed, a mechanically promoted inter-conversion between the two kinds of site is suggested. As a consequence, the hAl centres are effective in monitoring even modest activations of powders, through thermal or mechanical processes, and they are also supposed to play a specific, relevant role in quartz reactivity during the considered industrial processes.

  13. Comparing Meteorite and Spacecraft Noble Gas Measurements to Trace Processes in the Martian Crust and Atmosphere

    NASA Astrophysics Data System (ADS)

    Swindle, T. D.

    2014-12-01

    Our knowledge of the noble gas abundances and isotopic compositions in the Martian crust and atmosphere come from two sources, measurements of meteorites from Mars and in situ measurements by spacecraft. Measurements by the Viking landers had large uncertainties, but were precise enough to tie the meteorites to Mars. Hence most of the questions we have are currently defined by meteorite measurements. Curiosity's SAM has confirmed that the Ar isotopic composition of the atmosphere is highly fractionated, presumably representing atmospheric loss that can now be modeled with more confidence. What turns out to be a more difficult trait to explain is the fact that the ratio of Kr/Xe in nakhlites, chassignites and ALH84001 is distinct from the atmospheric ratio, as defined by measurements from shergottites. This discrepancy has been suggested to be a result of atmosphere/groundwater/rock interaction, polar clathrate formation, or perhaps local temperature conditions. More detailed atmospheric measurements, along with targeted simulation experiments, will be needed to make full use of this anomaly.

  14. V Xanes in Spinels as an Oxy-Barometer in Meteorites with Implications for Redox Variations in the Inner Solar System

    NASA Technical Reports Server (NTRS)

    Righter, K.; Sutton, S.; Danielson, L.; Pando, K.; Le, L.; Newville, M.

    2015-01-01

    The variation of oxygen fugacity within inner solar system materials spans a range of nearly 15 orders of magnitude. Igneous and metamorphic rocks commonly contain a mineral assemblage that allows oxygen fugacity to be calculated or con-strained such as FeTi oxides, olivine-opx-spinel, or some other oxy-barometer. Some rocks, however, contain a limited mineral assemblage and do not provide constraints on fO2 using mineral equilibria. Good examples of the latter are orthopyroxenites or dunites, such as diogenites, ALH 84001, chassignites, or brachinites. In fact it is no surprise that the fO2 of many of these achondrites is not well known, other than being "reduced" and below the metal saturation value. In order to bridge this gap in our understanding, we have initiated a study of V in chromites in achondrite. Because the V pre-edge peak intensity and energy in chromites varies with fO2, and this has been calibrated over a large fO2 range, we can apply this relation to rocks for which we otherwise have no fO2 constraints.

  15. Fertility and semen quality of workers exposed to high temperatures in the ceramics industry.

    PubMed

    Figà-Talamanca, I; Dell'Orco, V; Pupi, A; Dondero, F; Gandini, L; Lenzi, A; Lombardo, F; Scavalli, P; Mancini, G

    1992-01-01

    The objective of this study was to test the hypothesis that chronic occupational exposure to high temperatures may be detrimental to male reproduction. The study was based on 92 healthy ceramics oven operators with a long exposure to high temperatures, and 87 controls, recruited from the shipment department of the same industry. Interviews with all subjects provided data on sociodemographic characteristics, health status, and fertility problems. Semen analysis was carried out on 46 of the workers exposed to high temperatures, and 14 of the controls, and included evaluation of the sperm concentration, morphology, and motility, including computer-assisted sperm motion analysis (velocity, linearity, ALH, BCF). The results of the questionnaire showed that exposed individuals had a higher incidence of childlessness and of self-reported difficulty in conceiving than controls. The semen analysis showed no significant differences except in sperm velocity. Although differences in semen parameters, taken singly, were not statistically significant, the overall evaluation of the sperm parameters indicated a higher prevalence of pathologic sperm profiles among the exposed compared to the controls.

  16. Lunar and Planetary Science XXXV: Organics and Alteration in Carbonaceous Chondrites: Goop and Crud

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The session "Organics and Alteration in Carbonaceous Chondrites: Goop and Crud" included the following reports:Organics on Fe-Silicate Grains: Potential Mimicry of Meteoritic Processes?; Molecular and Compound-Specific Isotopic Study of Monocarboxylic Acids in Murchison and Antarctic Meteorites; Nanoglobules, Macromolecular Materials, and Carbon Sulfides in Carbonaceous Chondrites; Evidence for Terrestrial Organic Contamination of the Tagish Lake Meteorite; Nitrogen Isotopic Imaging of Tagish Lake Carbon Globules; Microscale Distribution of Hydrogen Isotopes in Two Carbonaceous Chondrites; The Nature and Origin of Aromatic Organic Matter in the Tagish Lake Meteorite; Terrestrial Alteration of CM Chondritic Carbonate; Serpentine Nanotubes in CM Chondrites; Experimental Study of Serpentinization Reactions; Chondrule Glass Alteration in Type IIA Chondrules in the CR2 Chondrites EET 87770 and EET 92105: Insights into Elemental Exchange Between Chondrules and Matrices; Aqueous Alteration of Carbonaceous Chondrites: New Insights from Comparative Studies of Two Unbrecciated CM2 Chondrites, Y 791198 and ALH 81002 ;and A Unique Style of Alteration of Iron-Nickel Metal in WIS91600, an Unusual C2 Carbonaceous Chondrite.

  17. Evidence from Hydrogen Isotopes in Meteorites for a Subsurface Hydrogen Reservoir on Mars

    NASA Technical Reports Server (NTRS)

    Usui, Tomohiro; Alexander, Conel M. O'D.; Wang, Jianhua; Simon, Justin I.; Jones, John H.

    2015-01-01

    The surface geology and geomorphology of Mars indicates that it was once warm enough to maintain a large body of liquid water on its surface, though such a warm environment might have been transient. The transition to the present cold and dry Mars is closely linked to the history of surface water, yet the evolution of surficial water is poorly constrained. We have conducted in situ hydrogen isotope (D/H) analyses of quenched and impact glasses in three Martian meteorites (Yamato 980459, EETA79001, LAR 06319) by Cameca ims-6f at Digital Terrain Models (DTM) following the methods of [1]. The hydrogen isotope analyses provide evidence for the existence of a distinct but ubiquitous water/ice reservoir (D/H = 2-3 times Earth's ocean water: Standard Mean Ocean Water (SMOW)) that lasted from at least the time when the meteorites crystallized (173-472 Ma) to the time they were ejected by impacts (0.7-3.3 Ma), but possibly much longer [2]. The origin of this reservoir appears to predate the current Martian atmospheric water (D/H equals approximately 5-6 times SMOW) and is unlikely to be a simple mixture of atmospheric and primordial water retained in the Martian mantle (D/H is approximately equal to SMOW [1]). Given the fact that this intermediate-D/H reservoir (2-3 times SMOW) is observed in a diverse range of Martian materials with different ages (e.g., SNC (Shergottites, Nakhlites, Chassignites) meteorites, including shergottites such as ALH 84001; and Curiosity surface data [3]), we conclude that this intermediate-D/H reservoir is likely a global surficial feature that has remained relatively intact over geologic time. We propose that this reservoir represents either hydrated crust and/or ground ice interbedded within sediments. Our results corroborate the hypothesis that a buried cryosphere accounts for a large part of the initial water budget of Mars.

  18. Organization of P, S, and Fe Inclusions in a Freshwater Magnetococcus

    NASA Technical Reports Server (NTRS)

    Cox, Lea; Popa Radu; Douglas, Susanne; Belz, Andrea; Nealson, Kenneth H.

    2001-01-01

    Magnetotactic bacteria are a heterogeneous group of motile, mainly aquatic procaryotes that align and swim along geomagnetic field lines. They are of interest to astrobiologists because of the magnetite crystals found in the Mars meteorite ALH84001 which share many characteristics with the magnetite produced intracellularly by magnetotactic bacteria. These bacteria are diverse morphologically, physiologically and phylogenetically, sharing a few key characteristics: 1) the presence of intracellular membrane-bound magnetic crystals (magnetosomes), usually but not always arranged in chains; 2) motility by means of flagella; and 3) microaerophillic or anaerobic physiology. The bilophotrichous (having two flagella bundles) magnetotactic cocci (MC) are ubiquitous in aquatic habitats but have proven extremely difficult to cultivate. Because only several marine strains have been isolated and grown in axenic culture, little is known about the physiology and the biogeochemical roles of the MC. We studied the composition and distribution of intracellular structures in an uncultured MC, designated ARB-1. To do this, a combination of light microscopy, environmental scanning electron microscopy (ESEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS) were used. Cells of ARB-1 were separated from sediments collected from Baldwin Lake (Los Angeles Arboretum, Arcadia, CA). They are large spherical to oblate spheroidal Gram-negative cells, ranging from 1 to 4 micrometers along the maximum dimension, which is perpendicular to the direction of swimming. Cells have two large phosphorus-containing inclusions that comprise a large percentage of the cell volume. Many smaller sulfur inclusions are located at the convex end of the cell. Most of the cellular Fe is present in the magnetosomes. These may be arranged as a clump at the concave end of the cell, near the two flagella bundles, or as chains, or as both a clump and chains. The magnetosomes were

  19. Field Emission Gun Scanning Electron (FEGSEM) and Transmission Electron (TEM) Microscopy of Phyllosilicates in Martian Meteorites ALH84001, Nakhla, and Shergotty

    NASA Technical Reports Server (NTRS)

    Thomas-Keprta, Kathie L.; Wentworth, Susan J.; McKay, David S.; Gibson, Everett K.

    2000-01-01

    Here we document the occurrence of phyllosilicates and alteration phases in three martian meteorites, suggest formation conditions required for phyllosilicate formation and speculate on the extent of fluid:rock interactions during the past history of Mars.

  20. A decade of change: an institutional experience with breast surgery in 1995 and 2005.

    PubMed

    Guth, Amber A; Shanker, Beth Ann; Roses, Daniel F; Axelrod, Deborah; Singh, Baljit; Toth, Hildegard; Shapiro, Richard L; Hiotis, Karen; Diflo, Thomas; Cangiarella, Joan F

    2008-01-01

    With the adoption of routine screening mammography, breast cancers are being diagnosed at earlier stages, with DCIS now accouting for 22.5% of all newly diagnosed breast cancers. This has been attributed to both increased breast cancer awareness and improvements in breast imaging techniques. How have these changes, including the increased use of image-guided sampling techniques, influenced the clinical practice of breast surgery? The institutional pathology database was queried for all breast surgeries, including breast reconstruction, performed in 1995 and 2005. Cosmetic procedures were excluded. The results were analysed utilizing the Chi-square test. Surgical indications changed during 10-year study period, with an increase in preoperatively diagnosed cancers undergoing definitive surgical management. ADH, and to a lesser extent, ALH, became indications for surgical excision. Fewer surgical biopsies were performed for indeterminate abnormalities on breast imaging, due to the introduction of stereotactic large core biopsy. While the rate of benign breast biopsies remained constant, there was a higher percentage of precancerous and DCIS cases in 2005. The overall rate of mastectomy decreased from 36.8% in 1995 to 14.5% in 2005. With the increase in sentinel node procedures, the rate of ALND dropped from 18.3% to 13.7%. Accompanying the increased recognition of early-stage cancers, the rate of positive ALND also decreased, from 43.3% to 25.0%. While the rate of benign breast biopsies has remained constant over a recent 10-year period, fewer diagnostic surgical image-guided biopsies were performed in 2005. A greater percentage of patients with breast cancer or preinvasive disease have these diagnoses determined before surgery. More preinvasive and Stage 0 cancers are undergoing surgical management. Earlier stage invasive cancers are being detected, reflected by the lower incidence of axillary nodal metastases.

  1. A Decade of Change: An Institutional Experience with Breast Surgery in 1995 and 2005

    PubMed Central

    Guth, Amber A.; Shanker, Beth Ann; Roses, Daniel F.; Axelrod, Deborah; Singh, Baljit; Toth, Hildegard; Shapiro, Richard L.; Hiotis, Karen; Diflo, Thomas; Cangiarella, Joan F.

    2008-01-01

    Introduction: With the adoption of routine screening mammography, breast cancers are being diagnosed at earlier stages, with DCIS now accouting for 22.5% of all newly diagnosed breast cancers. This has been attributed to both increased breast cancer awareness and improvements in breast imaging techniques. How have these changes, including the increased use of image-guided sampling techniques, influenced the clinical practice of breast surgery? Methods: The institutional pathology database was queried for all breast surgeries, including breast reconstruction, performed in 1995 and 2005. Cosmetic procedures were excluded. The results were analysed utilizing the Chi-square test. Results: Surgical indications changed during 10-year study period, with an increase in preoperatively diagnosed cancers undergoing definitive surgical management. ADH, and to a lesser extent, ALH, became indications for surgical excision. Fewer surgical biopsies were performed for indeterminate abnormalities on breast imaging, due to the introduction of stereotactic large core biopsy. While the rate of benign breast biopsies remained constant, there was a higher percentage of precancerous and DCIS cases in 2005. The overall rate of mastectomy decreased from 36.8% in 1995 to 14.5% in 2005. With the increase in sentinel node procedures, the rate of ALND dropped from 18.3% to 13.7%. Accompanying the increased recognition of early-stage cancers, the rate of positive ALND also decreased, from 43.3% to 25.0%. Conclusions: While the rate of benign breast biopsies has remained constant over a recent 10-year period, fewer diagnostic surgical image-guided biopsies were performed in 2005. A greater percentage of patients with breast cancer or preinvasive disease have these diagnoses determined before surgery. More preinvasive and Stage 0 cancers are undergoing surgical management. Earlier stage invasive cancers are being detected, reflected by the lower incidence of axillary nodal metastases. PMID

  2. Ground-based characterization of Hayabusa2 mission target asteroid 162173 Ryugu: constraining mineralogical composition in preparation for spacecraft operations

    NASA Astrophysics Data System (ADS)

    Le Corre, Lucille; Sanchez, Juan A.; Reddy, Vishnu; Takir, Driss; Cloutis, Edward A.; Thirouin, Audrey; Becker, Kris J.; Li, Jian-Yang; Sugita, Seiji; Tatsumi, Eri

    2018-03-01

    Asteroids that are targets of spacecraft missions are interesting because they present us with an opportunity to validate ground-based spectral observations. One such object is near-Earth asteroid (NEA) (162173) Ryugu, which is the target of the Japanese Space Agency's (JAXA) Hayabusa2 sample return mission. We observed Ryugu using the 3-m NASA Infrared Telescope Facility on Mauna Kea, Hawaii, on 2016 July 13 to constrain the object's surface composition, meteorite analogues, and link to other asteroids in the main belt and NEA populations. We also modelled its photometric properties using archival data. Using the Lommel-Seeliger model we computed the predicted flux for Ryugu at a wide range of viewing geometries as well as albedo quantities such as geometric albedo, phase integral, and spherical Bond albedo. Our computed albedo quantities are consistent with results from Ishiguro et al. Our spectral analysis has found a near-perfect match between our spectrum of Ryugu and those of NEA (85275) 1994 LY and Mars-crossing asteroid (316720) 1998 BE7, suggesting that their surface regoliths have similar composition. We compared Ryugu's spectrum with that of main belt asteroid (302) Clarissa, the largest asteroid in the Clarissa asteroid family, suggested as a possible source of Ryugu by Campins et al. We found that the spectrum of Clarissa shows significant differences with our spectrum of Ryugu, but it is similar to the spectrum obtained by Moskovitz et al. The best possible meteorite analogues for our spectrum of Ryugu are two CM2 carbonaceous chondrites, Mighei and ALH83100.

  3. A mutli-technique search for the most primitive CO chondrites

    NASA Astrophysics Data System (ADS)

    Alexander, C. M. O'D.; Greenwood, R. C.; Bowden, R.; Gibson, J. M.; Howard, K. T.; Franchi, I. A.

    2018-01-01

    As part of a study to identify the most primitive COs and to look for weakly altered CMs amongst the COs, we have conducted a multi-technique study of 16 Antarctic meteorites that had been classified as primitive COs. For this study, we have determined: (1) the bulk H, C and N abundances and isotopes, (2) bulk O isotopic compositions, (3) bulk modal mineralogies, and (4) for some selected samples the abundances and compositions of their insoluble organic matter (IOM). Two of the 16 meteorites do appear to be CMs - BUC 10943 seems to be a fairly typical CM, while MIL 090073 has probably been heated. Of the COs, DOM 08006 appears to be the most primitive CO identified to date and is quite distinct from the other members of its pairing group. The other COs fall into two groups that are less primitive than DOM 08006 and ALH 77307, the previously most primitive CO. The first group is composed of members of the DOM 08004 pairing group, except DOM 08006. The second group is composed of meteorites belonging to the MIL 03377 and MIL 07099 pairing groups. These two pairing groups should probably be combined. There is a dichotomy in the bulk O isotopes between the primitive (all Antarctic finds) and the more metamorphosed COs (mostly falls). This dichotomy can only partly be explained by the terrestrial weathering experienced by the primitive Antarctic samples. It seems that the more equilibrated samples interacted to a greater extent with 16O-poor material, probably water, than the more primitive meteorites.

  4. Inverse correlation between reactive oxygen species in unwashed semen and sperm motion parameters as measured by a computer-assisted semen analyzer.

    PubMed

    Takeshima, Teppei; Yumura, Yasushi; Yasuda, Kengo; Sanjo, Hiroyuki; Kuroda, Shinnosuke; Yamanaka, Hiroyuki; Iwasaki, Akira

    2017-01-01

    This study investigated the correlation between sperm motion parameters obtained by a computer-assisted semen analyzer and levels of reactive oxygen species in unwashed semen. In total, 847 patients, except for azoospermic patients were investigated. At the time of each patient's first consultation, semen parameters were measured using SMAS™ or CellSoft 3000™, and production of reactive oxygen species was measured using a computer-driven LKB Wallac Luminometer 1251 Analyzer. The patients were divided into two groups: reactive oxygen species - positive and negative. The semen parameters within each group were measured using one of the two computer-assisted semen analyzer systems and then compared. Correlations between reactive oxygen species levels and sperm motion parameters in semen from the reactive oxygen species - positive group were also investigated. Reactive oxygen species were detected in semen samples of 282 cases (33.3%). Sperm concentration (P < 0.01; P < 0.01), motility (P < 0.01; P < 0.05), and progressive motility (P < 0.01; P < 0.01) were markedly lower in the reactive oxygen species - positive group than in the reactive oxygen species - negative group. Among the sperm motion parameters in the reactive oxygen species - positive group, sperm concentration (P < 0.01; P < 0.01), motility (P < 0.05; P < 0.01), mALH (P < 0.05; P < 0.01), and progressive motility (P < 0.05; P < 0.01) also showed inverse correlations with the logarithmic transformed reactive oxygen species levels. Therefore, this study demonstrated that excessive reactive oxygen species in semen damage sperm concentration, motility, and other sperm motion parameters.

  5. Amino acid compositions in heated carbonaceous chondrites and their compound-specific nitrogen isotopic ratios

    NASA Astrophysics Data System (ADS)

    Chan, Queenie Hoi Shan; Chikaraishi, Yoshito; Takano, Yoshinori; Ogawa, Nanako O.; Ohkouchi, Naohiko

    2016-01-01

    A novel method has been developed for compound-specific nitrogen isotope compositions with an achiral column which was previously shown to offer high precision for nitrogen isotopic analysis. We applied the method to determine the amino acid contents and stable nitrogen isotopic compositions of individual amino acids from the thermally metamorphosed (above 500 °C) Antarctic carbonaceous chondrites Ivuna-like (CI)1 (or CI-like) Yamato (Y) 980115 and Ornans-like (CO)3.5 Allan Hills (ALH) A77003 with the use of gas chromatography/combustion/isotope ratio mass spectrometry. ALHA77003 was deprived of amino acids due to its extended thermal alteration history. Amino acids were unambiguously identified in Y-980115, and the δ15N values of selected amino acids (glycine +144.8 ‰; α-alanine +121.2 ‰) are clearly extraterrestrial. Y-980115 has experienced an extended period of aqueous alteration as indicated by the presence of hydrous mineral phases. It has also been exposed to at least one post-hydration short-lived thermal metamorphism. Glycine and alanine were possibly produced shortly after the accretion event of the asteroid parent body during the course of an extensive aqueous alteration event and have abstained from the short-term post-aqueous alteration heating due to the heterogeneity of the parent body composition and porosity. These carbonaceous chondrite samples are good analogs that offer important insights into the target asteroid Ryugu of the Hayabusa-2 mission, which is a C-type asteroid likely composed of heterogeneous materials including hydrated and dehydrated minerals.

  6. The provenance and formation of reduced carbon phases on Mars from the study of Martian meteorites.

    NASA Astrophysics Data System (ADS)

    Steele, A.; McCubbin, F. M.; Fries, M.

    2015-12-01

    Organic carbon compounds are essential building blocks of terrestrial life, so the occurrence and origin (biotic or abiotic) of organic compounds on Mars is of great significance. Indeed, the question of Martian organic matter is among the highest priority targets for robotic spacecraft missions in the next decade includ- ing the Mars Science Laboratory and Mars 2020. Sev- eral Martian meteorites contain organic carbon (i.e., macromolecular reduced carbon-rich material, not nec- essarily related to biota), but there is little agreement on its origins. Initial hypotheses for the origin of this organic carbon included: terrestrial contamination; chondritic meteoritic input; thermal decomposition of Martian carbonate minerals; direct precipitation from cooling aqueous fluids; and the remains of ancient Martian biota. We report on results from the analysis of 14 martian meteorites and show the distribution of organic phases throughout the samples analyzed. We will present formation scearios for each of the types of organic matter discovered. These studies when combined show 4 possible pools of reduced carbon on Mars. 1) impact generated graphite in the Tissint meteorite, 2) secondary hydrothermal generated graphite in ALH 84001, 3) primary igneous reduced carbon in 12 Martian meteorites associated with spinel inclusions in olivine and pyroxene 4) and potentially primary hydrothermally formed organic carbon / nitrogen containing organic species in the maskelynite phases of the Tissint meteorite. These studies show that Mars has produced reduced carbon / organic carbon via several mechanisms and reveal that the building blocks of life, if not life itself, are present on Mars.

  7. Amino acid distribution in meteorites: diagenesis, extraction methods, and standard metrics in the search for extraterrestrial biosignatures.

    PubMed

    McDonald, Gene D; Storrie-Lombardi, Michael C

    2006-02-01

    The relative abundance of the protein amino acids has been previously investigated as a potential marker for biogenicity in meteoritic samples. However, these investigations were executed without a quantitative metric to evaluate distribution variations, and they did not account for the possibility of interdisciplinary systematic error arising from inter-laboratory differences in extraction and detection techniques. Principal component analysis (PCA), hierarchical cluster analysis (HCA), and stochastic probabilistic artificial neural networks (ANNs) were used to compare the distributions for nine protein amino acids previously reported for the Murchison carbonaceous chondrite, Mars meteorites (ALH84001, Nakhla, and EETA79001), prebiotic synthesis experiments, and terrestrial biota and sediments. These techniques allowed us (1) to identify a shift in terrestrial amino acid distributions secondary to diagenesis; (2) to detect differences in terrestrial distributions that may be systematic differences between extraction and analysis techniques in biological and geological laboratories; and (3) to determine that distributions in meteoritic samples appear more similar to prebiotic chemistry samples than they do to the terrestrial unaltered or diagenetic samples. Both diagenesis and putative interdisciplinary differences in analysis complicate interpretation of meteoritic amino acid distributions. We propose that the analysis of future samples from such diverse sources as meteoritic influx, sample return missions, and in situ exploration of Mars would be less ambiguous with adoption of standardized assay techniques, systematic inclusion of assay standards, and the use of a quantitative, probabilistic metric. We present here one such metric determined by sequential feature extraction and normalization (PCA), information-driven automated exploration of classification possibilities (HCA), and prediction of classification accuracy (ANNs).

  8. Thermally stable green Ba(3)Y(PO(4))3:Ce(3+),Tb(3+) and red Ca(3)Y(AlO)(3)(BO(3))4:Eu(3+) phosphors for white-light fluorescent lamps.

    PubMed

    Huang, Chien-Hao; Kuo, Te-Wen; Chen, Teng-Ming

    2011-01-03

    A class of thermal stable of green-emitting phosphors Ba(3)Y(PO(4))(3):Ce(3+),Tb(3+) (BYP:Ce(3+),Tb(3+)) and red-emitting phosphors Ca(3)Y(AlO)(3)(BO(3))(4):Eu(3+) (CYAB:Eu(3+)) for white-light fluorescent lamps were synthesized by high temperature solid-state reaction. We observed a decay of only 3% at 150 °C for BYP:0.25Ce3+,0.25Tb3+ (3% for LaPO4:Ce(3+),Tb(3+)), and a decay of 4% for CYAB:0.5Eu(3+) (7% for Y(2)O(3):Eu(3+), 24% for Y(2)O(2)S:Eu(3+)). The emission intensity of composition-optimized Ba(3)(Y(0.5)Ce(0.25)Tb(0.25))(PO(4))(3) is 70% of that of commercial LaPO(4):Ce(3+),Tb(3+) phosphors, and the CIE chromaticity coordinates are found to be (0.323, 0.534). The emission intensity of Ca(3)(Y(0.5)Eu(0.5))(AlO)(3)(BO(3))(4) is 70% and 83% of those of Y(2)O(3):Eu(3+) and Y(2)O(2)S:Eu(3+) phosphors, respectively, and the CIE chromaticity coordinates are redder (0.652, 0.342) than those of Y(2)O(3):Eu(3+) (0.645, 0.347) and Y(2)O(2)S:Eu(3+) (0.647, 0.343). A white-light fluorescent lamp is fabricated using composition-optimized Ba(3)(Y(0.5)Ce(0.25)Tb(0.25))(PO(4))(3) and Ca(3)(Y(0.5)Eu(0.5))(AlO)(3)(BO(3))(4) phosphors and matching blue-emitting phosphors. The results indicate that the quality of the brightness and color reproduction is suitable for application in shortwave UV fluorescent lamps. The white-light fluorescent lamp displays CIE chromaticity coordinates of x = 0.33, y = 0.35, a warm white light with a correlated color temperature of 5646 K, and a color-rendering index of Ra = 70.

  9. Atmospheric Chemistry of (CF3)2CHOCH3, (CF3)2CHOCHO, and CF3C(O)OCH3.

    PubMed

    Østerstrøm, Freja From; Wallington, Timothy J; Sulbaek Andersen, Mads P; Nielsen, Ole John

    2015-10-22

    Smog chambers with in situ FTIR detection were used to measure rate coefficients in 700 Torr of air and 296 ± 2 K of: k(Cl+(CF3)2CHOCH3) = (5.41 ± 1.63) × 10(-12), k(Cl+(CF3)2CHOCHO) = (9.44 ± 1.81) × 10(-15), k(Cl+CF3C(O)OCH3) = (6.28 ± 0.98) × 10(-14), k(OH+(CF3)2CHOCH3) = (1.86 ± 0.41) × 10(-13), and k(OH+(CF3)2CHOCHO) = (2.08 ± 0.63) × 10(-14) cm(3) molecule(-1) s(-1). The Cl atom initiated oxidation of (CF3)2CHOCH3 gives (CF3)2CHOCHO in a yield indistinguishable from 100%. The OH radical initiated oxidation of (CF3)2CHOCH3 gives the following products (molar yields): (CF3)2CHOCHO (76 ± 8)%, CF3C(O)OCH3 (16 ± 2)%, CF3C(O)CF3 (4 ± 1)%, and C(O)F2 (45 ± 5)%. The primary oxidation product (CF3)2CHOCHO reacts with Cl atoms to give secondary products (molar yields): CF3C(O)CF3 (67 ± 7)%, CF3C(O)OCHO (28 ± 3)%, and C(O)F2 (118 ± 12)%. CF3C(O)OCH3 reacts with Cl atoms to give: CF3C(O)OCHO (80 ± 8)% and C(O)F2 (6 ± 1)%. Atmospheric lifetimes of (CF3)2CHOCH3, (CF3)2CHOCHO, and CF3C(O)OCH3 were estimated to be 62 days, 1.5 years, and 220 days, respectively. The 100-year global warming potentials (GWPs) for (CF3)2CHOCH3, (CF3)2CHOCHO, and CF3C(O)OCH3 are estimated to be 6, 121, and 46, respectively. A comprehensive description of the atmospheric fate of (CF3)2CHOCH3 is presented.

  10. Lunar and Planetary Science XXXVI, Part 19

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The topics include: 1) The abundances of Iron-60 in Pyroxene Chondrules from Unequilibrated Ordinary Chondrites; 2) LL-Ordinary Chondrite Impact on the Moon: Results from the 3.9 Ga Impact Melt at the Landing Site of Appolo 17; 3) Evaluation of Chemical Methods for Projectile Identification in Terrestrial and Lunar Impactites; 4) Impact Cratering Experiments in Microgravity Environment; 5) New Achondrites with High-Calcium Pyroxene and Its implication for Igneous Differentiation of Asteroids; 6) Climate History of the Polar Regions of Mars Deduced form Geologic Mapping Results; 7) The crater Production Function for Mars: A-2 Cumulative Power-Law Slope for Pristine Craters Greater than 5 km in Diameter Based on Crater Distribution for Northern Plains Materials; 8) High Resolution Al-26 Chronology: Resolved Time Interval Between Rim and Interior of a Highly Fractionated Compact Type a CAI from Efremovka; 9) Assessing Aqueous Alteration on Mars Using Global Distributions of K and Th; 10) FeNi Metal Grains in LaPaz Mare Basalt Meteorites and Appolo 12 Basalts; 11) Unique Properties of Lunar Soil for In Situ Resource Utilization on the Moon; 12) U-Pb Systematics of Phosphates in Nakhlites; 13) Measurements of Sound Speed in Granular Materials Simulated Regolith; 14) The Effects of Oxygen, Sulphur and Silicon on the Dihedral Angles Between Fe-rich Liquid Metal and Olivine, Ringwoodite and Silicate Perovskite: Implications for Planetary Core Formation; 15) Seismic Shaking Removal of Craters 0.2-0.5 km in Diameter on Asteroid 433 Eros; 16) Focused Ion Beam Microscoopy of ALH84001 Carbonate Disks; 17) Simulating Micro-Gravity in the Laboratory; 18) Mars Atmospheric Sample Return Instrument Development; 19) Combined Remote LIBS and Raman Spectroscopy Measurements; 20) Unusual Radar Backscatter Properties Along the Northern Rim of Imbrium Basin; 21) The Mars Express/NASAS Project at JPL; 22) The Geology of the Viking 2 Lander Site Revisited; 23) An Impact Genesis for Loki

  11. Relativistic GW calculations on CH3NH3PbI3 and CH3NH3SnI3 perovskites for solar cell applications.

    PubMed

    Umari, Paolo; Mosconi, Edoardo; De Angelis, Filippo

    2014-03-26

    Hybrid AMX3 perovskites (A = Cs, CH3NH3; M = Sn, Pb; X = halide) have revolutionized the scenario of emerging photovoltaic technologies, with very recent results demonstrating 15% efficient solar cells. The CH3NH3PbI3/MAPb(I(1-x)Cl(x))3 perovskites have dominated the field, while the similar CH3NH3SnI3 has not been exploited for photovoltaic applications. Replacement of Pb by Sn would facilitate the large uptake of perovskite-based photovoltaics. Despite the extremely fast progress, the materials electronic properties which are key to the photovoltaic performance are relatively little understood. Density Functional Theory electronic structure methods have so far delivered an unbalanced description of Pb- and Sn-based perovskites. Here we develop an effective GW method incorporating spin-orbit coupling which allows us to accurately model the electronic, optical and transport properties of CH3NH3SnI3 and CH3NH3PbI3, opening the way to new materials design. The different CH3NH3SnI3 and CH3NH3PbI3 electronic properties are discussed in light of their exploitation for solar cells, and found to be dominantly due to relativistic effects. These effects stabilize the CH3NH3PbI3 material towards oxidation, by inducing a deeper valence band edge. Relativistic effects, however, also increase the material band-gap compared to CH3NH3SnI3, due to the valence band energy downshift (~0.7 eV) being only partly compensated by the conduction band downshift (~0.2 eV).

  12. Relativistic GW calculations on CH3NH3PbI3 and CH3NH3SnI3 Perovskites for Solar Cell Applications

    PubMed Central

    Umari, Paolo; Mosconi, Edoardo; De Angelis, Filippo

    2014-01-01

    Hybrid AMX3 perovskites (A = Cs, CH3NH3; M = Sn, Pb; X = halide) have revolutionized the scenario of emerging photovoltaic technologies, with very recent results demonstrating 15% efficient solar cells. The CH3NH3PbI3/MAPb(I1−xClx)3 perovskites have dominated the field, while the similar CH3NH3SnI3 has not been exploited for photovoltaic applications. Replacement of Pb by Sn would facilitate the large uptake of perovskite-based photovoltaics. Despite the extremely fast progress, the materials electronic properties which are key to the photovoltaic performance are relatively little understood. Density Functional Theory electronic structure methods have so far delivered an unbalanced description of Pb- and Sn-based perovskites. Here we develop an effective GW method incorporating spin-orbit coupling which allows us to accurately model the electronic, optical and transport properties of CH3NH3SnI3 and CH3NH3PbI3, opening the way to new materials design. The different CH3NH3SnI3 and CH3NH3PbI3 electronic properties are discussed in light of their exploitation for solar cells, and found to be dominantly due to relativistic effects. These effects stabilize the CH3NH3PbI3 material towards oxidation, by inducing a deeper valence band edge. Relativistic effects, however, also increase the material band-gap compared to CH3NH3SnI3, due to the valence band energy downshift (~0.7 eV) being only partly compensated by the conduction band downshift (~0.2 eV). PMID:24667758

  13. Modeling the Hydrogen Solubility in Liquid Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    Harvey, Jean-Philippe; Chartrand, Patrice

    2010-08-01

    The modeling of hydrogen solubility in multicomponent Al-(Li, Mg, Cu, and Si) liquid phase has been performed with a thermodynamic approach using the modified quasichemical model with the pair approximation (MQMPA). All hydrogen solubility data available in literature was assessed critically to obtain the binary parameters of the MQMPA model for the Al-H, Li-H, Mg-H, Cu-H, Zn-H, and Si-H melts. For the Li-H system, a new thermodynamic description of the stable solid lithium hydride was determined based on the c p found in literature. The thermodynamic model for the Al-Li system also was reassessed in this work to take into account the short-range ordering observed for this system. Built-in interpolation techniques allow the model to estimate the thermodynamic properties of the multicomponent liquid solution from the liquid model parameters of the lower order subsystems. A comparison of the calculated hydrogen solubility performed at various equilibrium conditions of temperature, pressure, and composition with the available experimental data found in the literature is presented in this work, as well as a comparison with some results from previous modeling.

  14. Chlorine Abundances in Martian Meteorites

    NASA Technical Reports Server (NTRS)

    Bogard, D.D.; Garrison, D.H.; Park, J.

    2009-01-01

    Chlorine measurements made in martian surface rocks by robotic spacecraft typically give Chlorine (Cl) abundances of approximately 0.1-0.8%. In contrast, Cl abundances in martian meteorites appear lower, although data is limited, and martian nakhlites were also subjected to Cl contamination by Mars surface brines. Chlorine abundances reported by one lab for whole rock (WR) samples of Shergotty, ALH77005, and EET79001 range 108-14 ppm, whereas Cl in nakhlites range 73-1900 ppm. Measurements of Cl in various martian weathering phases of nakhlites varied 0.04-4.7% and reveal significant concentration of Cl by martian brines Martian meteorites contain much lower Chlorine than those measured in martian surface rocks and give further confirmation that Cl in these surface rocks was introduced by brines and weathering. It has been argued that Cl is twice as effective as water in lowering the melting point and promoting melting at shallower martian depths, and that significant Cl in the shergottite source region would negate any need for significant water. However, this conclusion was based on experiments that utilized Cl concentrations more analogous to martian surface rocks than to shergottite meteorites, and may not be applicable to shergottites.

  15. Improving promoter prediction for the NNPP2.2 algorithm: a case study using Escherichia coli DNA sequences.

    PubMed

    Burden, S; Lin, Y-X; Zhang, R

    2005-03-01

    Although a great deal of research has been undertaken in the area of promoter prediction, prediction techniques are still not fully developed. Many algorithms tend to exhibit poor specificity, generating many false positives, or poor sensitivity. The neural network prediction program NNPP2.2 is one such example. To improve the NNPP2.2 prediction technique, the distance between the transcription start site (TSS) associated with the promoter and the translation start site (TLS) of the subsequent gene coding region has been studied for Escherichia coli K12 bacteria. An empirical probability distribution that is consistent for all E.coli promoters has been established. This information is combined with the results from NNPP2.2 to create a new technique called TLS-NNPP, which improves the specificity of promoter prediction. The technique is shown to be effective using E.coli DNA sequences, however, it is applicable to any organism for which a set of promoters has been experimentally defined. The data used in this project and the prediction results for the tested sequences can be obtained from http://www.uow.edu.au/~yanxia/E_Coli_paper/SBurden_Results.xls alh98@uow.edu.au.

  16. Mn-53-Cr-53 Systematics of R-Chondrite NWA 753

    NASA Technical Reports Server (NTRS)

    Jogo, K.; Shih, C-Y.; Reese, Y. D.; Nyquist, L. E.

    2006-01-01

    Chondrules and chondrites are interpreted as objects formed in the early solar system, and it is important to study them in order to elucidate its evolution. Here, we report the study of the Mn-Cr systematics of the R-Chondrite NWA753 and compare the results to other chondrite data. The goal was to determine Cr isotopic and age variations among chondrite groups with different O-isotope signatures. The Mn-53-Cr-53 method as applied to individual chondrules [1] or bulk chondrites [2] is based on the assumption that 53Mn was initially homogeneously distributed in that portion the solar nebula where the chondrules and/or chondrites formed. However, different groups of chondrites formed from regions of different O-isotope compositions. So, different types of chondrites also may have had different initial Mn-53 abundances and/or Cr isotopic compositions. Thus, it is important to determine the Cr isotopic systematics among chondrites from various chondrite groups. We are studying CO-chondrite ALH83108 and Tagish Lake in addition to R-Chondrite NWA753. These meteorites have very distinct O-isotope compositions (Figure 1).

  17. Serial Interface through Stream Protocol on EPICS Platform for Distributed Control and Monitoring

    NASA Astrophysics Data System (ADS)

    Das Gupta, Arnab; Srivastava, Amit K.; Sunil, S.; Khan, Ziauddin

    2017-04-01

    Remote operation of any equipment or device is implemented in distributed systems in order to control and proper monitoring of process values. For such remote operations, Experimental Physics and Industrial Control System (EPICS) is used as one of the important software tool for control and monitoring of a wide range of scientific parameters. A hardware interface is developed for implementation of EPICS software so that different equipment such as data converters, power supplies, pump controllers etc. could be remotely operated through stream protocol. EPICS base was setup on windows as well as Linux operating system for control and monitoring while EPICS modules such as asyn and stream device were used to interface the equipment with standard RS-232/RS-485 protocol. Stream Device protocol communicates with the serial line with an interface to asyn drivers. Graphical user interface and alarm handling were implemented with Motif Editor and Display Manager (MEDM) and Alarm Handler (ALH) command line channel access utility tools. This paper will describe the developed application which was tested with different equipment and devices serially interfaced to the PCs on a distributed network.

  18. Unknown caller: can we effectively manage the announcement of discovery of extraterrestrial life?

    NASA Astrophysics Data System (ADS)

    Gartrelle, Gordon M.

    2015-10-01

    The definitive discovery of another form of life from beyond Earth will answer one of our most fundamental questions: Are we alone in the Universe? This announcement will be the most significant in history. It will have impact on every facet of our lives and affect everyone on Earth. Ensuring the announcement is handled properly represents an opportunity to unify government, industrial, and scientific resources to work together on a global scale issue. The purpose of the present paper is to understand whether we have the overall strategy, management structures and process disciplines in place on a global scale to handle an announcement of this magnitude. The research methodology included review and analysis of peer-reviewed work on the topic, publications from appropriate scientific and policy organizations, and public statements from several acknowledged experts in the field of astrobiology and extraterrestrial communications. The 1996 case of the announcement of possible life from Martian meteorite ALH84001 was also analysed. The findings of the paper are multiple deficiencies exist in the ability to manage this problem globally in an integrated fashion across borders, institutional boundaries, and through the media. High-level recommendations are offered to address major identified gaps.

  19. A high-performance aluminum-feed microfluidic fuel cell stack

    NASA Astrophysics Data System (ADS)

    Wang, Yifei; Leung, Dennis Y. C.

    2016-12-01

    In this paper, a six-cell microfluidic fuel cell (MFC) stack is demonstrated. Low-cost aluminum is fed directly to the stack, which produces hydrogen fuel on site, through the Al-H2O reaction. This design is not only cost-efficient, but also eliminates the need for hydrogen storage. Unlike the conventional MFC stacks which generally require complex electrolyte distribution and management, the present Al-feed MFC stack requires only a single electrolyte stream, flowing successively through individual cells, which is finally utilized for hydrogen generation. In this manner, the whole system is greatly simplified while the operational robustness is also improved. With 2 M sodium hydroxide solution as electrolyte and kitchen foil Al as fuel, the present six-cell stack (in series) exhibits an open circuit voltage of nearly 6 V and a peak power density of 180.6 mWcm-2 at room temperature. In addition, an energy density of 1 Whg-1(Al) is achieved, which is quite high and comparable with its proton exchange membrane-based counterparts. Finally, pumpless operation of the present stack, together with its practical applications are successfully demonstrated, including lightening LED lights, driving an electric fan, and cell phone charging.

  20. The Molybdenum(V) and Tungsten(VI) Oxoazides [MoO(N3 )3 ], [MoO(N3 )3 ⋅2 CH3 CN], [(bipy)MoO(N3 )3 ], [MoO(N3 )5 ](2-) , [WO(N3 )4 ], and [WO(N3 )4 ⋅CH3 CN].

    PubMed

    Haiges, Ralf; Skotnitzki, Juri; Fang, Zongtang; Dixon, David A; Christe, Karl O

    2015-12-14

    A series of novel molybdenum(V) and tungsten(VI) oxoazides was prepared starting from [MOF4 ] (M=Mo, W) and Me3 SiN3 . While [WO(N3 )4 ] was formed through fluoride-azide exchange in the reaction of Me3 SiN3 with WOF4 in SO2 solution, the reaction with MoOF4 resulted in a reduction of Mo(VI) to Mo(V) and formation of [MoO(N3 )3 ]. Carried out in acetonitrile solution, these reactions resulted in the isolation of the corresponding adducts [MoO(N3 )3 ⋅2 CH3 CN] and [WO(N3 )4 ⋅CH3 CN]. Subsequent reactions of [MoO(N3 )3 ] with 2,2'-bipyridine and [PPh4 ][N3 ] resulted in the formation and isolation of [(bipy)MoO(N3 )3 ] and [PPh4 ]2 [MoO(N3 )5 ], respectively. Most molybdenum(V) and tungsten(VI) oxoazides were fully characterized by their vibrational spectra, impact, friction and thermal sensitivity data and, in the case of [WO(N3 )4 ⋅CH3 CN], [(bipy)MoO(N3 )3 ], and [PPh4 ]2 [MoO(N3 )5 ], by their X-ray crystal structures. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Association rate constants for reactions between resonance-stabilized radicals: C 3H 3 + C 3H 3, C 3H 3 + C 3H 5, and C 3H 5 + C 3H 5

    DOE PAGES

    Georgievskii, Yuri; Miller, James A.; Klippenstein, Stephen J.

    2007-05-18

    Reactions between resonance-stabilized radicals play an important role in combustion chemistry. The theoretical prediction of rate coefficients and product distributions for such reactions is complicated by the fact that the initial complex-formation steps and some dissociation steps are barrierless. In this work, direct variable reaction coordinate transition state theory (VRC-TST) is used to predict accurately the association rate constants for the self and cross reactions of propargyl and allyl radicals. For each reaction, a set of multifaceted dividing surfaces is used to account for the multiple possible addition channels. Because of their resonant nature the geometric relaxation of the radicalsmore » is important. Here, the effect of this relaxation is explicitly calculated with the UB3LYP/cc-pvdz method for each mutual orientation encountered in the configurational integrals over the transition state dividing surfaces. The final energies are obtained from CASPT2/cc-pvdz calculations with all π-orbitals in the active space. Evaluations along the minimum energy path suggest that basis set corrections are negligible. The VRC-TST approach was also used to calculate the association rate constant and the corresponding number of states for the C 6H 5 + H → C 6H 6 exit channel of the C 3H 3 + C 3H 3 reaction, which is also barrierless. For this reaction, the interaction energies were evaluated with the CASPT2(2e,2o)/cc-pvdz method and a 1-D correction is included on the basis of CAS+1+2+QC/aug-cc-pvtz calculations for the CH 3 + H reference system. For the C 3H 3 + C 3H 3 reaction, the VRC-TST results for the energy and angular momentum resolved numbers of states in the entrance channels and in the C 6H 5 + H exit channel are incorporated in a master equation simulation to determine the temperature and pressure dependence of the phenomenological rate coefficients. The rate constants for the C 3H 3 + C 3H 3 and C 3H 5 + C 3H 5 self-reactions compare favorably

  2. TES/Aura L3 Ammonia (NH3) Daily V3 (TL3NH3D)

    Atmospheric Science Data Center

    2018-03-14

    ... TES Aura L1B Nadir Spatial Coverage:  5.3 x 8.5 km Spatial Resolution:  0.5 x 5 km ... Guide Documents:  Data User's Guide (PDF):  Level 3 Level 3 Algorithms, Requirements, & Products (PDF) ...

  3. Synthesis of 2,3-trans-3,4-cis- and 2,3-trans-3,4-trans-2,3,4-triphenyltetrahydrofurans.

    PubMed

    Munshi, K L; Dikshit, D K; Kapil, R S; Anand, N

    1974-04-01

    The synthesis of 2,3-trans-3,4-cis- and 2,3-trans-3,4-trans-2,3,4-triphenyltetrahydrofurans was undertaken because these compounds incorportae the essential structural features of certain 2,3-diphenyl-benzofurans and 1,2,3-triphenylalkanones reported earlier to have marked antifertility activity. The synthesis of the 2 tetrahydrofurans was achieved by the cyclization of corresponding 2,3,4-triphenylbutane-1,4-diols upon heating with dimethyl sulfoxide (DMSO). The butane 1,4-diols were in turn prepared either by direct litium aluminum hydride (LAH) reduction of methyl 3-benzoyl-2,3-diphenylpropionates or by conversion of these propionates to delta-3,4-butryrolactones followed by LAH reduction. The propionates were prepared from the Fiedel-Crafts reaction of 2,3-diphenylsuccinic anhydride with benzene. Tetrahydrofurans were tested for their antiimplantation activity in rats. 2,3-trans-3,4-cis-2,4-diphenyl-3-p -(beta-pyrrolidinoethoxy) phenyltetrahydrofuran oxalate was found to inhibit implantation completely at 50 mg/kg, but was inefective at a lower dose.

  4. Catalytic dehydrofluorination of 1,1,1,3,3-pentafluoropropane to 1,3,3,3-tetrafluoropropene over fluorinated NiO/Cr2O3 catalysts

    NASA Astrophysics Data System (ADS)

    Luo, Jian-Wei; Song, Jian-Dong; Jia, Wen-Zhi; Pu, Zhi-Ying; Lu, Ji-Qing; Luo, Meng-Fei

    2018-03-01

    Catalytic dehydrofluorination of 1,1,1,3,3-pentafluoropropane to 1,3,3,3-tetrafluoropropene was performed on a series of fluorinated NiO/Cr2O3 catalysts. The NiO/Cr2O3 catalysts were more active than the Cr2O3 because the new acid sites provided by NiF2 had higher turnover frequencies (9.43 × 10-3 - 12.08 × 10-3 s-1) than those on the Cr2O3 (4.55 × 10-3 s-1). Also, the NiO/Cr2O3 was more stable than the Cr2O3 due to its lower density of surface acid sites, which alleviated the coke deposition on the catalyst as evidenced by the Raman spectroscopic results. The kinetic results revealed that the15NiO/Cr2O3 had much lower activation energy (63.6 ± 4.5 kJ mol-1) than the Cr2O3 (127.6 ± 3.8 kJ mol-1). Accordingly, different reaction pathways on the two catalysts were proposed, which involved the cleavage of the Csbnd F and Csbnd H bonds on the surface acid and base sites, respectively.

  5. a Matlab Geodetic Software for Processing Airborne LIDAR Bathymetry Data

    NASA Astrophysics Data System (ADS)

    Pepe, M.; Prezioso, G.

    2015-04-01

    The ability to build three-dimensional models through technologies based on satellite navigation systems GNSS and the continuous development of new sensors, as Airborne Laser Scanning Hydrography (ALH), data acquisition methods and 3D multi-resolution representations, have contributed significantly to the digital 3D documentation, mapping, preservation and representation of landscapes and heritage as well as to the growth of research in this fields. However, GNSS systems led to the use of the ellipsoidal height; to transform this height in orthometric is necessary to know a geoid undulation model. The latest and most accurate global geoid undulation model, available worldwide, is EGM2008 which has been publicly released by the U.S. National Geospatial-Intelligence Agency (NGA) EGM Development Team. Therefore, given the availability and accuracy of this geoid model, we can use it in geomatics applications that require the conversion of heights. Using this model, to correct the elevation of a point does not coincide with any node must interpolate elevation information of adjacent nodes. The purpose of this paper is produce a Matlab® geodetic software for processing airborne LIDAR bathymetry data. In particular we want to focus on the point clouds in ASPRS LAS format and convert the ellipsoidal height in orthometric. The algorithm, valid on the whole globe and operative for all UTM zones, allows the conversion of ellipsoidal heights using the EGM2008 model. Of this model we analyse the slopes which occur, in some critical areas, between the nodes of the undulations grid; we will focus our attention on the marine areas verifying the impact that the slopes have in the calculation of the orthometric height and, consequently, in the accuracy of the in the 3-D point clouds. This experiment will be carried out by analysing a LAS APRS file containing topographic and bathymetric data collected with LIDAR systems along the coasts of Oregon and Washington (USA).

  6. Host-sensitized luminescence properties in CaNb2O6:Ln(3+) (Ln(3+) = Eu(3+)/Tb(3+)/Dy(3+)/Sm(3+)) phosphors with abundant colors.

    PubMed

    Li, Kai; Liu, Xiaoming; Zhang, Yang; Li, Xuejiao; Lian, Hongzhou; Lin, Jun

    2015-01-05

    A series of Ln(3+) (Ln(3+) = Eu(3+)/Tb(3+)/Dy(3+)/Sm(3+)) ion doped CaNb2O6 (CNO) phosphors have been prepared via the conventional high-temperature solid-state reaction route. The X-ray diffraction (XRD) and structure refinement, diffuse reflection, photoluminescence (PL), and fluorescent decay curves were used to characterize the as-prepared samples. Under UV radiation, the CNO host present a broad emission band from about 355 to 605 nm centered around 460 nm originating from the NbO6 octahedral groups, which has spectral overlaps with the excitation of f-f transitions of Eu(3+)/Tb(3+)/Dy(3+)/Sm(3+) in CNO:Eu(3+)/Tb(3+)/Dy(3+)/Sm(3+) samples. They show both host emission and respective emission lines derived from the characteristic f-f transitions of activators, which present different emission colors owing to the energy transfer from the NbO6 group in the host to Eu(3+)/Tb(3+)/Dy(3+)/Sm(3+) with increasing activator concentrations. The decreases of decay lifetimes of host emissions in CNO:Eu(3+)/Tb(3+)/Dy(3+)/Sm(3+) demonstrate the energy transfer from the hosts to Eu(3+)/Tb(3+)/Dy(3+)/Sm(3+). The energy transfer mechanisms in CNO:Eu(3+)/Tb(3+)/Dy(3+) phosphors have been determined to be a resonant type via dipole-dipole mechanisms. For CNO:Sm(3+), the metal-metal charge transfer transition (MMCT) might contribute to the different variations of decay lifetimes and emission intensity from CNO:Eu(3+)/Tb(3+)/Dy(3+) samples. The best quantum efficiency is 71.2% for CNO:0.01/0.02Dy(3+). The PL properties of as-prepared materials indicate the promising application in UV-pumped white-emitting lighting diodes field.

  7. 28 CFR 3.3 - Registration.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Registration. 3.3 Section 3.3 Judicial Administration DEPARTMENT OF JUSTICE GAMBLING DEVICES § 3.3 Registration. Persons required to register pursuant to section 3 of the Act shall register with the Assistant Attorney General, Criminal Division...

  8. 28 CFR 3.3 - Registration.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 28 Judicial Administration 1 2011-07-01 2011-07-01 false Registration. 3.3 Section 3.3 Judicial Administration DEPARTMENT OF JUSTICE GAMBLING DEVICES § 3.3 Registration. Persons required to register pursuant to section 3 of the Act shall register with the Assistant Attorney General, Criminal Division...

  9. 28 CFR 3.3 - Registration.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 28 Judicial Administration 1 2012-07-01 2012-07-01 false Registration. 3.3 Section 3.3 Judicial Administration DEPARTMENT OF JUSTICE GAMBLING DEVICES § 3.3 Registration. Persons required to register pursuant to section 3 of the Act shall register with the Assistant Attorney General, Criminal Division...

  10. 28 CFR 3.3 - Registration.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 28 Judicial Administration 1 2014-07-01 2014-07-01 false Registration. 3.3 Section 3.3 Judicial Administration DEPARTMENT OF JUSTICE GAMBLING DEVICES § 3.3 Registration. Persons required to register pursuant to section 3 of the Act shall register with the Assistant Attorney General, Criminal Division...

  11. 28 CFR 3.3 - Registration.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 28 Judicial Administration 1 2013-07-01 2013-07-01 false Registration. 3.3 Section 3.3 Judicial Administration DEPARTMENT OF JUSTICE GAMBLING DEVICES § 3.3 Registration. Persons required to register pursuant to section 3 of the Act shall register with the Assistant Attorney General, Criminal Division...

  12. 17 CFR 3.3 - [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 17 Commodity and Securities Exchanges 1 2013-04-01 2013-04-01 false [Reserved] 3.3 Section 3.3 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION REGISTRATION Registration § 3.3 [Reserved] ...

  13. 17 CFR 3.3 - [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 17 Commodity and Securities Exchanges 1 2012-04-01 2012-04-01 false [Reserved] 3.3 Section 3.3 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION REGISTRATION Registration § 3.3 [Reserved] ...

  14. Real-Space Bonding Indicator Analysis of the Donor-Acceptor Complexes X3BNY3, X3AlNY3, X3BPY3, and X3AlPY3 (X, Y = H, Me, Cl).

    PubMed

    Mebs, Stefan; Beckmann, Jens

    2017-10-12

    Calculations of real-space bonding indicators (RSBI) derived from Atoms-In-Molecules (AIM), Electron Localizability Indicator (ELI-D), Non-Covalent Interactions index (NCI), and Density Overlap Regions Indicator (DORI) toolkits for a set of 36 donor-acceptor complexes X 3 BNY 3 (1, 1a-1h), X 3 AlNY 3 (2, 2a-2h), X 3 BPY 3 (3, 3a-3h), and X 3 AlPY 3 (4, 4a-4h) reveal that the donor-acceptor bonds comprise covalent and ionic interactions in varying extents (X = Y = H for 1-4; X = H, Y = Me for 1a-4a; X = H, Y = Cl for 1b-4b; X = Me, Y = H for 1c-4c; X, Y = Me for 1d-4d; X = Me, Y = Cl for 1e-4e; X = Cl, Y = H for 1f-4f; X = Cl, Y = Me for 1g-4g; X, Y = Cl for 1h-4h). The phosphinoboranes X 3 BPY 3 (3, 3a-3h) in general and Cl 3 BPMe 3 (3f) in particular show the largest covalent contributions and the least ionic contributions. The aminoalanes X 3 AlNY 3 (2, 2a-2h) in general and Me 3 AlNCl 3 (2e) in particular show the least covalent contributions and the largest ionic contributions. The aminoboranes X 3 BNY 3 (1, 1a-1h) and the phosphinoalanes X 3 AlPY 3 (4, 4a-4h) are midway between phosphinoboranes and aminoalanes. The degree of covalency and ionicity correlates with the electronegativity difference BP (ΔEN = 0.15) < AlP (ΔEN = 0.58) < BN (ΔEN = 1.00) < AlN (ΔEN = 1.43) and a previously published energy decomposition analysis (EDA). To illustrate the importance of both contributions in Lewis formula representations, two resonance formulas should be given for all compounds, namely, the canonical form with formal charges denoting covalency and the arrow notation pointing from the donor to the acceptor atom to emphasis ionicity. If the Lewis formula mainly serves to show the atomic connectivity, the most significant should be shown. Thus, it is legitimate to present aminoalanes using arrows; however, for phosphinoboranes the canonical form with formal charges is more appropriate.

  15. 22 CFR 3.3 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 22 Foreign Relations 1 2013-04-01 2013-04-01 false Definitions. 3.3 Section 3.3 Foreign Relations DEPARTMENT OF STATE GENERAL GIFTS AND DECORATIONS FROM FOREIGN GOVERNMENTS § 3.3 Definitions. When used in... described in paragraph (b)(1) of this section; (3) any agent or representative of any such unit or...

  16. 22 CFR 3.3 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 22 Foreign Relations 1 2012-04-01 2012-04-01 false Definitions. 3.3 Section 3.3 Foreign Relations DEPARTMENT OF STATE GENERAL GIFTS AND DECORATIONS FROM FOREIGN GOVERNMENTS § 3.3 Definitions. When used in... described in paragraph (b)(1) of this section; (3) any agent or representative of any such unit or...

  17. 22 CFR 3.3 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Definitions. 3.3 Section 3.3 Foreign Relations DEPARTMENT OF STATE GENERAL GIFTS AND DECORATIONS FROM FOREIGN GOVERNMENTS § 3.3 Definitions. When used in... described in paragraph (b)(1) of this section; (3) any agent or representative of any such unit or...

  18. 22 CFR 3.3 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 22 Foreign Relations 1 2014-04-01 2014-04-01 false Definitions. 3.3 Section 3.3 Foreign Relations DEPARTMENT OF STATE GENERAL GIFTS AND DECORATIONS FROM FOREIGN GOVERNMENTS § 3.3 Definitions. When used in... described in paragraph (b)(1) of this section; (3) any agent or representative of any such unit or...

  19. Methanesulfonates of high-valent metals: syntheses and structural features of MoO2(CH3SO3)2, UO2(CH3SO3)2, ReO3(CH3SO3), VO(CH3SO3)2, and V2O3(CH3SO3)4 and their thermal decomposition under N2 and O2 atmosphere.

    PubMed

    Betke, Ulf; Neuschulz, Kai; Wickleder, Mathias S

    2011-11-04

    Oxide methanesulfonates of Mo, U, Re, and V have been prepared by reaction of MoO(3), UO(2)(CH(3)COO)(2)·2H(2)O, Re(2)O(7)(H(2)O)(2), and V(2)O(5) with CH(3)SO(3)H or mixtures thereof with its anhydride. These compounds are the first examples of solvent-free oxide methanesulfonates of these elements. MoO(2)(CH(3)SO(3))(2) (Pbca, a=1487.05(4), b=752.55(2), c=1549.61(5) pm, V=1.73414(9) nm(3), Z=8) contains [MoO(2)] moieties connected by [CH(3)SO(3)] ions to form layers parallel to (100). UO(2)(CH(3)SO(3))(2) (P2(1)/c, a=1320.4(1), b=1014.41(6), c=1533.7(1) pm, β=112.80(1)°, V=1.8937(3) nm(3), Z=8) consists of linear UO(2)(2+) ions coordinated by five [CH(3)SO(3)] ions, forming a layer structure. VO(CH(3)SO(3))(2) (P2(1)/c, a=1136.5(1), b=869.87(7), c=915.5(1) pm, β=113.66(1)°, V=0.8290(2) nm(3), Z=4) contains [VO] units connected by methanesulfonate anions to form corrugated layers parallel to (100). In ReO(3)(CH(3)SO(3)) (P1, a=574.0(1), b=1279.6(3), c=1641.9(3) pm, α=102.08(2), β=96.11(2), γ=99.04(2)°, V=1.1523(4) nm(3), Z=8) a chain structure exhibiting infinite O-[ReO(2)]-O-[ReO(2)]-O chains is formed. Each [ReO(2)]-O-[ReO(2)] unit is coordinated by two bidentate [CH(3)SO(3)] ions. V(2)O(3)(CH(3)SO(3))(4) (I2/a, a=1645.2(3), b=583.1(1), c=1670.2(3) pm, β=102.58(3), V=1.5637(5) pm(3), Z=4) adopts a chain structure, too, but contains discrete [VO]-O-[VO] moieties, each coordinated by two bidentate [CH(3)SO(3)] ligands. Additional methanesulfonate ions connect the [V(2)O(3)] groups along [001]. Thermal decomposition of the compounds was monitored under N(2) and O(2) atmosphere by thermogravimetric/differential thermal analysis and XRD measurements. Under N(2) the decomposition proceeds with reduction of the metal leading to the oxides MoO(2), U(3)O(7), V(4)O(7), and VO(2); for MoO(2)(CH(3)SO(3))(2), a small amount of MoS(2) is formed. If the thermal decomposition is carried out in a atmosphere of O(2) the oxides MoO(3) and V(2)O(5) are formed. Copyright

  20. 38 CFR 3.3 - Pension.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2012-07-01 2012-07-01 false Pension. 3.3 Section 3.3 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation General § 3.3 Pension. (a) Pension for veterans—(1) Service...

  1. 38 CFR 3.3 - Pension.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2011-07-01 2011-07-01 false Pension. 3.3 Section 3.3 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation General § 3.3 Pension. (a) Pension for veterans—(1) Service...

  2. 38 CFR 3.3 - Pension.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2013-07-01 2013-07-01 false Pension. 3.3 Section 3.3 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation General § 3.3 Pension. (a) Pension for veterans—(1) Service...

  3. 38 CFR 3.3 - Pension.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Pension. 3.3 Section 3.3 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation General § 3.3 Pension. (a) Pension for veterans—(1) Service...

  4. 38 CFR 3.3 - Pension.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2014-07-01 2014-07-01 false Pension. 3.3 Section 3.3 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation General § 3.3 Pension. (a) Pension for veterans—(1) Service...

  5. 32 CFR 3.3 - Applicability.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 1 2014-07-01 2014-07-01 false Applicability. 3.3 Section 3.3 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE ACQUISITION TRANSACTIONS OTHER THAN CONTRACTS, GRANTS, OR COOPERATIVE AGREEMENTS FOR PROTOTYPE PROJECTS § 3.3 Applicability. This part applies to the...

  6. 32 CFR 3.3 - Applicability.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 1 2013-07-01 2013-07-01 false Applicability. 3.3 Section 3.3 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE ACQUISITION TRANSACTIONS OTHER THAN CONTRACTS, GRANTS, OR COOPERATIVE AGREEMENTS FOR PROTOTYPE PROJECTS § 3.3 Applicability. This part applies to the...

  7. 32 CFR 3.3 - Applicability.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 1 2011-07-01 2011-07-01 false Applicability. 3.3 Section 3.3 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE ACQUISITION TRANSACTIONS OTHER THAN CONTRACTS, GRANTS, OR COOPERATIVE AGREEMENTS FOR PROTOTYPE PROJECTS § 3.3 Applicability. This part applies to the...

  8. 32 CFR 3.3 - Applicability.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 1 2012-07-01 2012-07-01 false Applicability. 3.3 Section 3.3 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE ACQUISITION TRANSACTIONS OTHER THAN CONTRACTS, GRANTS, OR COOPERATIVE AGREEMENTS FOR PROTOTYPE PROJECTS § 3.3 Applicability. This part applies to the...

  9. Reactivity of Hydrogen and Methanol on (001) Surfaces of WO3, ReO3, WO3/ReO3 and ReO3/WO3

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

    Ling, Sanliang; Mei, Donghai; Gutowski, Maciej S.

    2011-05-16

    Bulk tungsten trioxide (WO3) and rhenium trioxide (ReO3) share very similar structures but display different electronic properties. WO3 is a wide bandgap semiconductor while ReO3 is an electronic conductor. With the advanced molecular beam epitaxy techniques, it is possible to make heterostructures comprised of layers of WO3 and ReO3. These heterostructures might display reactivity different than pure WO3 and ReO3. The interactions of two probe molecules (hydrogen and methanol) with the (001) surfaces of WO3, ReO3, and two heterostructures ReO3/WO3 and WO3/ReO3 were investigated at the density functional theory level. Atomic hydrogen prefers to adsorb at the terminal O1C sitesmore » forming a surface hydroxyl on four surfaces. Dissociative adsorption of a hydrogen molecule at the O1C site leads to formation of a water molecule adsorbed at the surface M5C site. This is thermodynamically the most stable state. A thermodynamically less stable dissociative state involves two surface hydroxyl groups O1CH and O2CH. The interaction of molecular hydrogen and methanol with pure ReO3 is stronger than with pure WO3 and the strength of the interaction substantially changes on the WO3/ReO3 and ReO3/WO3 heterostructures. The reaction barriers for decomposition and recombination reactions are sensitive to the nature of heterostructure. The calculated adsorption energy of methanol on WO3(001) of -65.6 kJ/mol is consistent with the previous experimental estimation of -67 kJ/mol. This material is based upon work supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences.« less

  10. NIR emission using Ce3+→Nd3+ energy transfer in Ba3Ce(PO4)3:Nd3+ phosphor

    NASA Astrophysics Data System (ADS)

    Tumram, P. V.; Moharil, S. V.

    2018-05-01

    In the System CePO4-Ba3(PO4)2, the intermediate compound Ba3Ce(PO4)3, is well known. In recent years, luminescence of rare earths has been studied in this host. However, there are no reports on the NIR emission in Ba3Ce(PO4)3. Here, NIR emission resulting from Ce3+→Nd3+ energy transfer in Ba3Ce(PO4)3 host is reported. This could be relevant for applications in bioimaging, telecommunication, solar photovoltaics, Photodynamic therapy, photostimulated localized hyperthermia, etc.

  11. Hydrothermal synthesis and tunable luminescence of CaSiO{sub 3}:RE{sup 3+}(RE{sup 3+} = Eu{sup 3+}, Sm{sup 3+}, Tb{sup 3+}, Dy{sup 3+}) nanocrystals

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

    Fu, Linlin; Yang, Xingxing; Fu, Zuoling, E-mail: zlfu@jlu.edu.cn

    2015-05-15

    Highlights: • Near-spherical CaSiO{sub 3} nanocrystals were synthesized via a hydrothermal method. • The effect of calcination temperature on crystalline phase formation was discussed. • Optical properties of trivalent ions doped CaSiO{sub 3} nanocrystals were investigated. • Tunable luminescence of CaSiO{sub 3}:Tb{sup 3+}, Eu{sup 3+} can be achieved by a simple method. - Abstract: CaSiO{sub 3}:RE{sup 3+} (RE{sup 3+} = Eu{sup 3+}, Sm{sup 3+}, Tb{sup 3+}, Dy{sup 3+}) nanocrystals were prepared by facile hydrothermal method with further calcinations. The crystal structure and the effects of annealing temperature on phase transition have been characterized by X-ray diffraction (XRD). The photoluminescence (PL)more » and PL excitation (PLE) spectra were used to characterize the optical properties of all samples. The effect of Eu{sup 3+} and Sm{sup 3+} doping concentrations on the luminescent intensity were also investigated in details, respectively. Moreover, the luminescence colors of the Tb{sup 3+} and Eu{sup 3+} co-doped CaSiO{sub 3} samples can be tuned by simply adjusting the relative doping concentrations of the rare earth ions under a single wavelength excitation, which might find potential applications in the fields of light display systems and optoelectronic devices.« less

  12. 21 CFR 3.3 - Scope.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Scope. 3.3 Section 3.3 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PRODUCT JURISDICTION Assignment of Agency Component for Review of Premarket Applications § 3.3 Scope. This section applies to: (a) Any...

  13. 7 CFR 3.3 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 1 2011-01-01 2011-01-01 false Definitions. 3.3 Section 3.3 Agriculture Office of the Secretary of Agriculture DEBT MANAGEMENT General § 3.3 Definitions. For the purpose of this part, except as where otherwise specifically provided, the term or terms: Agency means a subagency, office, or...

  14. 7 CFR 3.3 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 1 2013-01-01 2013-01-01 false Definitions. 3.3 Section 3.3 Agriculture Office of the Secretary of Agriculture DEBT MANAGEMENT General § 3.3 Definitions. For the purpose of this part, except as where otherwise specifically provided, the term or terms: Agency means a subagency, office, or...

  15. 7 CFR 3.3 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 1 2012-01-01 2012-01-01 false Definitions. 3.3 Section 3.3 Agriculture Office of the Secretary of Agriculture DEBT MANAGEMENT General § 3.3 Definitions. For the purpose of this part, except as where otherwise specifically provided, the term or terms: Agency means a subagency, office, or...

  16. 7 CFR 3.3 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 1 2014-01-01 2014-01-01 false Definitions. 3.3 Section 3.3 Agriculture Office of the Secretary of Agriculture DEBT MANAGEMENT General § 3.3 Definitions. For the purpose of this part, except as where otherwise specifically provided, the term or terms: Agency means a subagency, office, or...

  17. 21 CFR 3.3 - Scope.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Scope. 3.3 Section 3.3 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PRODUCT JURISDICTION Assignment of Agency Component for Review of Premarket Applications § 3.3 Scope. This section applies to: (a) Any...

  18. 21 CFR 3.3 - Scope.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Scope. 3.3 Section 3.3 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PRODUCT JURISDICTION Assignment of Agency Component for Review of Premarket Applications § 3.3 Scope. This section applies to: (a) Any...

  19. 21 CFR 3.3 - Scope.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Scope. 3.3 Section 3.3 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PRODUCT JURISDICTION Assignment of Agency Component for Review of Premarket Applications § 3.3 Scope. This section applies to: (a) Any...

  20. 7 CFR 3.3 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... (Federal agencies and private sector entities) into their respective databases for the purpose of... 7 Agriculture 1 2010-01-01 2010-01-01 false Definitions. 3.3 Section 3.3 Agriculture Office of the Secretary of Agriculture DEBT MANAGEMENT General § 3.3 Definitions. For the purpose of this part, except as...

  1. 45 CFR 3.3 - Compliance.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 45 Public Welfare 1 2011-10-01 2011-10-01 false Compliance. 3.3 Section 3.3 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION CONDUCT OF PERSONS AND TRAFFIC ON THE NATIONAL INSTITUTES OF HEALTH FEDERAL ENCLAVE General § 3.3 Compliance. A person must comply with the regulations in...

  2. 45 CFR 3.3 - Compliance.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Compliance. 3.3 Section 3.3 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION CONDUCT OF PERSONS AND TRAFFIC ON THE NATIONAL INSTITUTES OF HEALTH FEDERAL ENCLAVE General § 3.3 Compliance. A person must comply with the regulations in...

  3. Synthesis of 1,3,3-trinitroazetidine

    DOEpatents

    Hiskey, Michael A.; Coburn, Michael D.

    1994-01-01

    A process of preparing 1,3,3-trinitroazetidine including forming a 5-hydroxymethyl-5-nitro-1-alkyltetrahydro-1,3-oxazine, e.g., reacting a 1,3,5-trialkyl hexahydrotriazine and tris(hydroxymethyl)nitromethane, ring opening said 5-hydroxymethyl-5-nitro-1-alkyltetrahydro-1,3-oxazine to form a 3-alkylamino-2-hydroxymethyl-2-nitro-1-propanol salt, ring closing said 3-alkylamino-2-hydroxymethyl-2-nitro-1-propanol salt to form a 3-hydroxymethyl-3-nitro-1-alkylazetidine salt, nitrating said 3-hydroxymethyl-3-nitro-1-alkylazetidine salt to form a 1-alkyl-3,3-dinitroazetidine, and converting said 1-alkyl-3,3-dinitroazetidine into 1,3,3-trinitroazetidine is disclosed.

  4. Synthesis of 1,3,3-trinitroazetidine

    DOEpatents

    Hiskey, M.A.; Coburn, M.D.

    1994-08-09

    A process of preparing 1,3,3-trinitroazetidine includes forming a 5-hydroxymethyl-5-nitro-1-alkyltetrahydro-1,3-oxazine, e.g., reacting a 1,3,5-trialkyl hexahydrotriazine and tris(hydroxymethyl)nitromethane, ring opening said 5-hydroxymethyl-5-nitro-1-alkyltetrahydro-1,3-oxazine to form a 3-alkylamino-2-hydroxymethyl-2-nitro-1-propanol salt, ring closing said 3-alkylamino-2-hydroxymethyl-2-nitro-1-propanol salt to form a 3-hydroxymethyl-3-nitro-1-alkylazetidine salt, nitrating said 3-hydroxymethyl-3-nitro-1-alkylazetidine salt to form a 1-alkyl-3,3-dinitroazetidine, and converting said 1-alkyl-3,3-dinitroazetidine into 1,3,3-trinitroazetidine is disclosed. 1 fig.

  5. Electron driven processes in sulphur containing compounds CH3SCH3 and CH3SSCH3

    NASA Astrophysics Data System (ADS)

    Kopyra, Janina; Władziński, Jakub

    2015-06-01

    Dissociative electron attachment to gas phase dimethyl sulphide (CH3SCH3) and dimethyl disulphide (CH3SSCH3) has been studied by means of a crossed beams apparatus. Cleavage of the C-S bond within CH3SCH3 and the S-S bond within CH3SSCH3 is observed within a resonance in the energy range below 2 eV and visible preferentially via the appearance of the fragment CH2S-. The striking finding is that the intensity of CH2S- generated from CH3SSCH3 is more than two orders of magnitude higher than the intensity of the respective anionic fragment generated from CH3SCH3. Our results clearly demonstrate that the CH3SSCH3 molecule, which contains disulphide bridge is substantially more sensitive towards electron attachment resulting mainly in dissociation along the S-S bridge.

  6. Annihilation rates of 3D2(2--) and 3D3(3--) heavy quarkonia

    NASA Astrophysics Data System (ADS)

    Wang, Tianhong; Fu, Hui-Feng; Jiang, Yue; Li, Qiang; Wang, Guo-Li

    2017-03-01

    We calculate the annihilation decay rates of the 3D 2(2--) and 3D 3(3--) charmonia and bottomonia by using the instantaneous Bethe-Salpeter (BS) method. The wave functions of states with quantum numbers JPC = 2-- and 3-- are constructed. By solving the corresponding instantaneous BS equations, we obtain the mass spectra and wave functions of the quarkonia. The annihilation amplitude is written within Mandelstam formalism and the relativistic corrections are taken into account properly. This is important, especially for high excited states, since their relativistic corrections are large. The results for the 3g channel are as follows: Γ13D2(cc¯)→ggg = 9.24 keV, Γ13D3(cc¯)→ggg = 25.0 keV, Γ13D2(bb¯)→ggg = 1.87 keV and Γ13D3(bb¯)→ggg = 0.815 keV.

  7. Decomposition of P(CH 3) 3 on Ru(0001): comparison with PH 3 and PCl 3

    NASA Astrophysics Data System (ADS)

    Tao, H.-S.; Diebold, U.; Shinn, N. D.; Madey, T. E.

    1997-04-01

    The decomposition of P(CH 3) 3 adsorbed on Ru(0001) at 80 K is studied by soft X-ray photoelectron spectroscopy using synchrotron radiation. Using the chemical shifts in the P 2p core levels, we are able to identify various phosphorus-containing surface reaction products and follow their reactions on Ru(0001). It is found that P(CH 3) 3 undergoes a step-wise demethylation on Ru(0001), P(CH 3) 3 → P(CH 3) 2 → P(CH 3) → P, which is complete around ˜450 K. These results are compared with the decomposition of isostructural PH 3 and PCl 3 on Ru(0001). The decomposition of PH 3 involves a stable intermediate, labeled as PH x, and follows a reaction of: PH 3 → PH x → P, which is complete around ˜190 K. The conversion of chemisorbed phosphorus to ruthenium phosphide is observed and is complete around ˜700 K on Ru(0001). PCl 3 also follows a step-wise decomposition reaction, PCl 3 → PCl 2 → PCl → P, which is complete around ˜300 K. The energetics of the adsorption and the step-wise decomposition reactions of PH 3, PCl 3 and P(CH 3) 3 are estimated using the bond order conservation Morse potential (BOCMP) method. The energetics calculated using the BOCMP method agree qualitatively with the experimental data.

  8. Tunable emission in Ln3+ (Ce3+/Dy3+, Ce3+/Tb3+) doped KNa3Al4Si4O16 phosphor synthesized by combustion method

    NASA Astrophysics Data System (ADS)

    Kolte, M. M.; Pawade, V. B.; Bhattacharya, A. B.; Dhoble, S. J.

    2018-05-01

    Ln3+ (Ln = Ce3+/Dy3+, Ce3+/Tb3+) doped KNa3Al4Si4O16 phosphor has been synthesized by Combustion method (CS) at 550° C successfully. Ln3+ (Ln = Ce3+, Dy3+, Tb3+) ions when doped in KNa3Al4Si4O16 host lattice, it shows blue and green emission band under the near Ultraviolet (NUV) excitation wavelength. The Photoluminescence excitation (PLE) and emission spectra are observed due to f-f and d-f transition of rare earth ions. Also, an effective energy transfer (ET) study from Ce3+ → Dy3+ and Ce3+ → Tb3+ ions has been studied and confirmed on the basis of Dexter-Foster theory. Further synthesized phosphor is well characterized by XRD, SEM, TEM and decay time measurement. However, the analysis of crystallite size, lattice strain has been studied by using theoretical as well as experimental techniques. Hence, the observed tunable emission in Ln3+ doped KNa3Al4Si4O16 phosphor may be applicable for solid state lighting technology.

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

    Spitz, A.H.; Boynton, W.V.

    Six ureilites (ALHA77257, ALHA81101, ALH82130, PCA82506, Kanna, and Novo Urei) were analyzed using neutron activation analysis for Ca, Sc, Cr, Mn, Fe, Co, Ni, Zn, Ga, REE, W, Re, Os, Ir, and Au. The authors examined bulk samples as well as acid-treated samples. In bulk samples the refractory siderophiles' concentrations range from approximately 0.1 to 1.0 times CI chondrites while the volatile siderophiles' concentrations range from approximately 0.1 to 1.0 times CI chondrites while the volatile siderophiles range from about 0.07 to 0.3 times CI chondrites. Rare earth elements (REEs) in ureilites are quite depleted and display light and heavymore » rare earth enrichments. The Antarctic meteorites display either much less pronounced v-shaped patterns or no enrichment in the light rare earths at all. In terms of the new trace-element results, ureilites do not fall into the coherent groups that other workers have defined by chemical or petrographic characteristics. Trace elements do provide additional constraints on the models for the petrogenesis of ureilites. In particular, the siderophile element abundances call for simplified models of chemical processing rather than the complex, multistage processing called for in silicate fractionation models. REE concentrations, on the other hand, imply multistage processing to produce the ureilites. None of the ureilite petrogenesis models extant account for the trace element data. These new data and the considerations of them with respect to the proposed ureilite petrogenesis models indicate that the direction of modeling should be toward contemplation of mixtures and how the components the authors observe in ureilites behave under such conditions.« less

  10. Compound-Specific Carbon, Nitrogen, and Hydrogen Isotopic Ratios for Amino Acids in CM and CR Chondrites and their use in Evaluating Potential Formation Pathways

    NASA Technical Reports Server (NTRS)

    Elsila, Jamie E.; Charnley, Steven B.; Burton, Aaron S.; Glavin, Daniel P.; Dworkin, Jason P.

    2012-01-01

    Stable hydrogen, carbon, and nitrogen isotopic ratios (oD, 013C, and olSN) of organic compounds can revcal information about their origin and formation pathways. Several formation mechanisms and environments have been postulated for the amino acids detected in carbonaceous chondrites. As each proposed mechanism utilizes different precursor molecules, the isotopic signatures of the resulting amino acids may indicate the most likely of these pathways. We have applied gas chromatography with mass spectrometry and combustion isotope ratio mass spectrometry to measure the compound-specific C, N, and H stable isotopic ratios of amino acids from seven CM and CR carbonaceous chondrites: CM1I2 Allan Hills (ALH) 83100, CM2 Murchison, CM2 Lewis Cliff (LEW) 90500, CM2 Lonewolf Nunataks (LON) 94101, CRZ Graves Nunataks (GRA) 95229, CRZ Elephant Moraine (EET) 92042, and CR3 Queen Alexandra Range (QUE) 99177. We compare the isotopic compositions of amino acids in these meteorites with predictions of expected isotopic enrichments from potential formation pathways. We observe trends of decreasing ODC and increasing oD with increasing carbon number in the aH, (l-NH2 amino acids that correspond to predictions made for formation via Streckercyanohydrin synthesis. We also observe light ODC signatures for -alanine, which may indicate either formation via Michael addition or via a pathway that forms primarily small, straight-chain, amine-terminal amino acids (n-ro-amino acids). Higher deuterium enrichments are observed in amethyl amino acids, indicating formation of these amino acids or their precursors in cold interstellar or nebular environments. Finally, individual amino acids are more enriched in deuterium in CR chondrites than CM chondrites, reflecting different parent-body chemistry.

  11. A Terrestrial Analogue from Spitsbergen (Svalbard, Norway) for the Comanche Carbonate at Gusev Crater, Mars

    NASA Technical Reports Server (NTRS)

    Morris, Richard V.; Blake, D. F.; Bish, D.; Ming, Douglas W.; Agresti, D. G.; Treiman, A. H.; Steele, A.; Amundsen, H. E. F.

    2011-01-01

    Carbonate occurs at the Comanche outcrops in Gusev Crater on the basis of analyses made by the Mars Exploration Rover Spirit [1]. Taken together, mineralogical data from Spirit's Moessbauer (MB) and Mini-TES spectrometer and chemical data from the APXS spectrometer show that Comanche carbonate has an Mg-Fe-rich bulk chemical composition, is present at high concentrations, and is distributed throughout the outcrop and not just at the MB and APXS analysis location. The granular outcrop texture and the observation that it appears to be resistant to weathering compared with surrounding material [1] imply that the carbonate may be present as a cement. A hydrothermal origin for the Comanche carbonate was inferred by analogy with laboratory experiments and with a carbonate occurrence within the Bockfjord volcanic complex on the island Spitsbergen (Svalbard, Norway) [1]. The laboratory carbonates, synthesized by precipitation from hydrothermal solutions, have (MB) parameters and average bulk chemical compositions that are characteristic of Comanche carbonate. The connection to Comanche carbonate is only through chemical data for certain occurrences of Spitsbergen carbonates. In fact, the common average bulk chemical composition for these Spitsbergen carbonates, the synthetic carbonates, the Comanche carbonate, and also the carbonate globules found in martian meteorite ALH84001 is a chemical constraint consistent with a hydrothermal formation process for all the carbonates [e.g., 1-3]. We develop here a link between MB data for the Comanche carbonate from MER and MB data for certain Spitsbergen carbonate occurrences from laboratory measurements. We also obtained visible and near- IR spectra on Spitsbergen carbonates for comparison with martian carbonate detections made on the basis of CRISM spectral data, e.g., in Nili Fossae [4].

  12. Understanding the role of Ti in reversible hydrogen storage as sodium alanate: a combined experimental and density functional theoretical approach.

    PubMed

    Chaudhuri, Santanu; Graetz, Jason; Ignatov, Alex; Reilly, James J; Muckerman, James T

    2006-09-06

    We report the results of an experimental and theoretical study of hydrogen storage in sodium alanate (NaAlH(4)). Reversible hydrogen storage in this material is dependent on the presence of 2-4% Ti dopant. Our combined study shows that the role of Ti may be linked entirely to Ti-containing active catalytic sites in the metallic Al phase present in the dehydrogenated NaAlH(4). The EXAFS data presented here show that dehydrogenated samples contain a highly disordered distribution of Ti-Al distances with no long-range order beyond the second coordination sphere. We have used density functional theory techniques to calculate the chemical potential of possible Ti arrangements on an Al(001) surface for Ti coverages ranging from 0.125 to 0.5 monolayer (ML) and have identified those that can chemisorb molecular hydrogen via spontaneous or only moderately activated pathways. The chemisorption process exhibits a characteristic nodal symmetry property for the low-barrier sites: the incipient doped surface-H(2) adduct's highest occupied molecular orbital (HOMO) incorporates the sigma antibonding molecular orbital of hydrogen, allowing the transfer of charge density from the surface to dissociate the molecular hydrogen. This work also proposes a plausible mechanism for the transport of an aluminum hydride species back into the NaH lattice that is supported by Car-Parrinello molecular dynamics (CPMD) simulations of the stability and mobility of aluminum clusters (alanes) on Al(001). As an experimental validation of the proposed role of titanium and the subsequent diffusion of alanes, we demonstrate experimentally that AlH(3) reacts with NaH to form NaAlH(4) without any requirement of a catalyst or hydrogen overpressure.

  13. EPR studies of Er 3+, Nd 3+ and Ce 3+ in YAlO 3 single crystals

    NASA Astrophysics Data System (ADS)

    Asatryan, H. R.; Rosa, J.; Mareš, J. A.

    1997-10-01

    EPR spectra of Er 3+, Nd 3+ and Ce 3+ ions in YAlO 3 lattice have been studied. These spectra can be described by spin Hamiltonian with an effective spin S = {1}/{2} and rhombohedric symmetry. The g factors as well as the constants of hyperfine interaction of Nd 3+ and Er 3+ were obtained. It was stated that all the resonances which are upon the interest of this article, belong to the RE 3+ ions replacing the Y 3+ cations in the YAlO 3 lattice.

  14. 3,3-Dimethylbenzidine

    Integrated Risk Information System (IRIS)

    3,3 - Dimethylbenzidine ; CASRN 119 - 93 - 7 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcin

  15. 3,3\\'-Dichlorobenzidine

    Integrated Risk Information System (IRIS)

    3,3 ' - Dichlorobenzidine ; CASRN 91 - 94 - 1 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarci

  16. 14-3-3 α and 14-3-3 ζ contribute to immune responses in planarian Dugesia japonica.

    PubMed

    Lu, Qingqing; Wu, Suge; Zhen, Hui; Deng, Hongkuan; Song, Qian; Ma, Kaifu; Cao, Zhonghong; Pang, Qiuxiang; Zhao, Bosheng

    2017-06-05

    14-3-3 proteins are a family of highly conserved acidic proteins that regulate cellular processes. They act as a kind of important signaling molecules taking part in many crucial decisions throughout the development process. We have isolated and characterized two members of the 14-3-3 family, namely, Dj14-3-3 α and Dj14-3-3 ζ in the planarian Dugesia japonica. The Dj14-3-3 α and ζ genes encode polypeptides of 260 and 255 amino acids respectively. We have proved that the Dj14-3-3 α and ζ genes were especially expressed in the pharynx in adult and regenerating planarians by in situ hybridization and they were not involved in regeneration process. Besides, Dj14-3-3 α and ζ genes can compensate each other in planarians by RNA interference. The Dj14-3-3 α and ζ were significantly up-regulated expression when planarians were stimulated with the pathogen-associated molecular patterns including lipopolysaccharide (LPS), peptidoglycan (PGN), β-Glu and Poly (I:C), indicating that the Dj14-3-3 α and ζ may be involved in the immune responses. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. 45 CFR 3.3 - Compliance.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 45 Public Welfare 1 2013-10-01 2013-10-01 false Compliance. 3.3 Section 3.3 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION CONDUCT OF PERSONS AND TRAFFIC ON THE NATIONAL... other authorized person, including traffic and parking directions. ...

  18. 45 CFR 3.3 - Compliance.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 45 Public Welfare 1 2012-10-01 2012-10-01 false Compliance. 3.3 Section 3.3 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION CONDUCT OF PERSONS AND TRAFFIC ON THE NATIONAL... other authorized person, including traffic and parking directions. ...

  19. 45 CFR 3.3 - Compliance.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 45 Public Welfare 1 2014-10-01 2014-10-01 false Compliance. 3.3 Section 3.3 Public Welfare Department of Health and Human Services GENERAL ADMINISTRATION CONDUCT OF PERSONS AND TRAFFIC ON THE NATIONAL... other authorized person, including traffic and parking directions. ...

  20. The onset of metamorphism in ordinary and carbonaceous chondrites

    USGS Publications Warehouse

    Grossman, J.N.; Brearley, A.J.

    2005-01-01

    subdivide types 3.0 and 3.1 into types 3.00 through 3.15. On this basis, the most primitive ordinary chondrite known is Semarkona, although even this meteorite has experienced a small amount of metamorphism. Allan Hills (ALH) A77307 is the least metamorphosed CO chondrite and shares many properties with the ungrouped carbonaceous chondrite Acfer 094. Analytical problems are significant for glasses in type II chondrules, as Na is easily lost during microprobe analysis. As a result, existing schemes for chondrule classification that are based on the alkali content of glasses need to be revised. ?? The Meteorological Society, 2005.

  1. Total cross sections of electron scattering by molecules NF3, PF3, N(CH3)3, P(CH3)3, NH(CH3)2, PH(CH3)2, NH2CH3 and PH2CH3 at 30-5000 eV

    NASA Astrophysics Data System (ADS)

    Shi, D. H.; Sun, J. F.; Zhu, Z. L.; Liu, Y. F.

    2010-04-01

    Total cross sections of electron scattering by eight molecules NF3, PF3, N(CH3)3, P(CH3)3, NH(CH3)2, PH(CH3)2, NH2CH3 and PH2CH3, which have some structural similarities, are calculated at the Hartree-Fork level by the modified additivity rule approach [D.H. Shi, J.F. Sun, Z.L. Zhu, H. Ma, Y.F. Liu, Eur. Phys. J. D 45, 253 (2007); D.H. Shi, J.F. Sun, Y.F. Liu, Z.L. Zhu, X.D. Yang, Chin. Opt. Lett. 4, 192 (2006)]. The modified additivity rule approach takes into considerations that the contributions of the geometric shielding effect vary as the energy of incident electrons, the dimension of target molecule, the number of electrons in the molecule and the number of atoms constituting the molecule. The present investigations cover the impact energy range from 30 to 5000 eV. The quantitative total cross sections are compared with those obtained by experiments and other theories. Excellent agreement is observed even at energies of several tens of eV. It shows that the modified additivity rule approach is applicable to carry out the total cross section calculations of electron scattering by these molecules at intermediate and high energies, in particular over the energy range above 80 eV or so. It proves that the microscopic molecular properties, such as the geometrical size of the target and the number of atoms constituting the molecule, are of crucial importance in the TCS calculations. The new results for PH(CH3)2 and PH2CH3 are also presented at energies from 30 to 5000 eV, although no experimental and theoretical data are available for comparison. In the present calculations, the atoms are still represented by the spherical complex optical potential, which is composed of static, exchange, polarization and absorption terms.

  2. The system Na2CO3-CaCO3 at 3 GPa

    NASA Astrophysics Data System (ADS)

    Podborodnikov, Ivan V.; Shatskiy, Anton; Arefiev, Anton V.; Rashchenko, Sergey V.; Chanyshev, Artem D.; Litasov, Konstantin D.

    2018-04-01

    It was suggested that alkali-alkaline earth carbonates may have a substantial role in petrological processes relevant to metasomatism and melting of the Earth's mantle. Because natrite, Na2CO3, Na-Ca carbonate (shortite and/or nyerereite), and calcite, CaCO3, have been recently reported from xenoliths of shallow mantle (110-115 km) origin, we performed experiments on phase relations in the system Na2CO3-CaCO3 at 3 GPa and 800-1300 °C. We found that the system has one intermediate compound, Na2Ca3(CO3)4, at 800 °C, and two intermediate compounds, Na2Ca(CO3)2 and Na2Ca3(CO3)4, at 850 °C. CaCO3 crystals recovered from experiments at 950 and 1000 °C are aragonite and calcite, respectively. Maximum solid solution of CaCO3 in Na2CO3 is 20 mol% at 850 °C. The Na-carbonate-Na2Ca(CO3)2 eutectic locates near 860 °C and 56 mol% Na2CO3. Na2Ca(CO3)2 melts incongruently near 880 °C to produce Na2Ca3(CO3)4 and a liquid containing about 51 mol% Na2CO3. Na2Ca3(CO3)4 disappears above 1000 °C via incongruent melting to calcite and a liquid containing about 43 mol% Na2CO3. At 1050 °C, the liquid, coexisting with Na-carbonate, contains 87 mol% Na2CO3. Na-carbonate remains solid up to 1150 °C and melts at 1200 °C. The Na2CO3 content in the liquid coexisting with calcite decreases to 15 mol% as temperature increases to 1300 °C. Considering the present and previous data, a range of the intermediate compounds on the liquidus of the Na2CO3-CaCO3 join changes as pressure increases in the following sequence: Na2Ca(CO3)2 (0.1 GPa) → Na2Ca(CO3)2, Na2Ca3(CO3)4 (3 GPa) → Na4Ca(CO3)3, Na2Ca3(CO3)4 (6 GPa). Thus, the Na2Ca(CO3)2 nyerereite stability field extends to the shallow mantle pressures. Consequently, findings of nyerereite among daughter phases in the melt inclusions in olivine from the sheared garnet peridotites are consistent with their mantle origin.

  3. 12 CFR 3.3 - Transitional rules.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 1 2011-01-01 2011-01-01 false Transitional rules. 3.3 Section 3.3 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY MINIMUM CAPITAL RATIOS; ISSUANCE OF DIRECTIVES Authority and Definitions § 3.3 Transitional rules. Intangible assets, other than mortgage...

  4. 12 CFR 3.3 - Transitional rules.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 1 2012-01-01 2012-01-01 false Transitional rules. 3.3 Section 3.3 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY MINIMUM CAPITAL RATIOS; ISSUANCE OF DIRECTIVES Authority and Definitions § 3.3 Transitional rules. Intangible assets, other than mortgage...

  5. 12 CFR 3.3 - Transitional rules.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 1 2013-01-01 2013-01-01 false Transitional rules. 3.3 Section 3.3 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY MINIMUM CAPITAL RATIOS; ISSUANCE OF DIRECTIVES Authority and Definitions § 3.3 Transitional rules. Intangible assets, other than mortgage...

  6. 43 CFR 3105.3-3 - Requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Requirements. 3105.3-3 Section 3105.3-3 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT... § 3105.3-3 Requirements. The contract shall be accompanied by a statement showing all the interests held...

  7. 43 CFR 3105.3-3 - Requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Requirements. 3105.3-3 Section 3105.3-3 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT... § 3105.3-3 Requirements. The contract shall be accompanied by a statement showing all the interests held...

  8. 43 CFR 3105.3-3 - Requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Requirements. 3105.3-3 Section 3105.3-3 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT... § 3105.3-3 Requirements. The contract shall be accompanied by a statement showing all the interests held...

  9. 10 CFR 960.3-3 - Consultation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Consultation. 960.3-3 Section 960.3-3 Energy DEPARTMENT OF ENERGY GENERAL GUIDELINES FOR THE PRELIMINARY SCREENING OF POTENTIAL SITES FOR A NUCLEAR WASTE REPOSITORY Implementation Guidelines § 960.3-3 Consultation. The DOE shall provide to designated officials of the affected...

  10. 10 CFR 960.3-3 - Consultation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Consultation. 960.3-3 Section 960.3-3 Energy DEPARTMENT OF ENERGY GENERAL GUIDELINES FOR THE PRELIMINARY SCREENING OF POTENTIAL SITES FOR A NUCLEAR WASTE REPOSITORY Implementation Guidelines § 960.3-3 Consultation. The DOE shall provide to designated officials of the affected...

  11. 10 CFR 960.3-3 - Consultation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Consultation. 960.3-3 Section 960.3-3 Energy DEPARTMENT OF ENERGY GENERAL GUIDELINES FOR THE PRELIMINARY SCREENING OF POTENTIAL SITES FOR A NUCLEAR WASTE REPOSITORY Implementation Guidelines § 960.3-3 Consultation. The DOE shall provide to designated officials of the affected...

  12. 10 CFR 960.3-3 - Consultation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Consultation. 960.3-3 Section 960.3-3 Energy DEPARTMENT OF ENERGY GENERAL GUIDELINES FOR THE PRELIMINARY SCREENING OF POTENTIAL SITES FOR A NUCLEAR WASTE REPOSITORY Implementation Guidelines § 960.3-3 Consultation. The DOE shall provide to designated officials of the affected...

  13. Tunable upconversion luminescence of monodisperse Y2O3: Er3+/Yb3+/Tm3+ nanoparticles

    NASA Astrophysics Data System (ADS)

    Wu, Qibai; Lin, Shaoteng; Xie, Zhongxiang; Zhang, Liqing; Qian, Yannan; Wang, Yaodong; Zhang, Haiyan

    2017-12-01

    Monodisperse Y2O3: Er3+/Yb3+/Tm3+ nanoparticles with various dopant concentrations have been synthesized successfully by a homogeneous precipitation method. Their phase structures and surface morphologies have been characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The diversities of upconversion luminescence spectra and CIE coordinates of prepared samples are investigated in detail at room temperature under 980 nm excitation. Through adjusting the concentrations of Yb3+, Tm3+ and Er3+ ions, three upconversion emission bands in red, green and blue region could be tunable to achieve the color of interest and near white light emission can be obtained in the tri-doped Y2O3 nanoparticles for a variety of application.

  14. Reactions at the Metal Vertex of a Monometal Metallocarborane Cluster. The Chemistry of (closo-3,3-(PPh3)2-3-(HSO4)-3,1,2-RhC2B9H11) and (closo-3-(PPh3)-3,3-(NO3)-3,1,2RhC2B9H11).

    DTIC Science & Technology

    1982-03-09

    4) produced by dissociation of PPh 3 from (2) or through an ionic species such as [closo-3,3- (PPh 3)2 -3,1,2-RhC 289 H ] [HSO4 (4a). Secondly, the...acetylene molecule and subsequent insertion into a metal-carbon bond has been observed in the linear oligomerization of acetylere catalyzed by [Ni(CO...monoxide were obtained from Liquid Carbonic and used without further treatment. Phenylacetylene (Aldrich) was distilled under vacuum before use and n

  15. 43 CFR 3742.3-3 - Publication.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Publication. 3742.3-3 Section 3742.3-3... Under the Act § 3742.3-3 Publication. (a) Upon receipt of a Request for Publication and accompanying... expense of the requesting person (who prior to the commencement of publication must furnish the agreement...

  16. 43 CFR 3742.3-3 - Publication.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Publication. 3742.3-3 Section 3742.3-3... Under the Act § 3742.3-3 Publication. (a) Upon receipt of a Request for Publication and accompanying... expense of the requesting person (who prior to the commencement of publication must furnish the agreement...

  17. 43 CFR 3742.3-3 - Publication.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Publication. 3742.3-3 Section 3742.3-3... Under the Act § 3742.3-3 Publication. (a) Upon receipt of a Request for Publication and accompanying... expense of the requesting person (who prior to the commencement of publication must furnish the agreement...

  18. 43 CFR 3742.3-3 - Publication.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Publication. 3742.3-3 Section 3742.3-3... Under the Act § 3742.3-3 Publication. (a) Upon receipt of a Request for Publication and accompanying... expense of the requesting person (who prior to the commencement of publication must furnish the agreement...

  19. Broken SU(3) x SU(3) x SU(3) x SU(3) Symmetry

    DOE R&D Accomplishments Database

    Freund, P. G. O.; Nambu, Y.

    1964-10-01

    We argue that the "Eight-fold Way" version of the SU(3) symmetry should be extended to a product of up to four separate and badly broken SU(3) groups, including the gamma{sub 5} type SU(3) symmetry. A hierarchy of subgroups (or subalgebras) are considered within this framework, and two candidates are found to be interesting in view of experimental evidence. Main features of the theory are: 1) the baryons belong to a nonet; 2) there is an octet of axial vector gauge mesons in addition to one or two octets of vector mesons; 3) pseudoscalar and scalar mesons exist as "incomplete" multiplets arising from spontaneous breakdown of symmetry.

  20. Study of Ce3+, Dy3+ and Eu3+ activated SrSnO3 for white LEDs

    NASA Astrophysics Data System (ADS)

    Jain, Neha; Pandey, Deepak Kumar; Singh, Rajan Kumar; Singh, Jai; Singh, R. A.

    2018-05-01

    Herein, Eu3+- Dy3+-Ce3+ tri-doped SrSnO3 have been prepared by conventional sol-gel method. XRD analysis confirmed its orthorhombic phase with Pnma (62) space group symmetry. The morphology of the sample is flake like which has examined by SEM. SrSnO3 consists of several vibrational modes due to Sn-O bond which was analysed by Fourier transform Infrared (FTIR) spectra. Photoluminescence (PL) emission and excitation spectra have been recorded for optical analysis. It consist characteristic emission peaks of Ce3+, Dy3+ and Eu3. The intensity of 590 nm emission increases with increasing Eu3+ concentration and it is maximum for 3 at% Eu3+ co-doped sample. The CIE chromaticity co-ordinates are found near white region so it would be a promising phosphor for white LEDs.

  1. Nuclear Hyperfine Structure in the Donor – Acceptor Complexes (CH3)3N-BF3 and (CH)33N-B(CH3)3

    EPA Science Inventory

    The donor-acceptor complexes (CH3)3N-BF3 and (CH3)3N-B(CH3)3 have been reinvestigated at high resolution by rotational spectroscopy in a supersonic jet. Nuclear hyperfine structure resulting from both nitrogen and boron has been resolved and quadrupole coupling constants have bee...

  2. 31 CFR 3.3 - Legal review.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance: Treasury 1 2014-07-01 2014-07-01 false Legal review. 3.3 Section 3.3 Money... OF DEPARTMENT OF TREASURY EMPLOYEES Claims Under the Federal Tort Claims Act § 3.3 Legal review. Any... that is likely to result in multiple claimants, shall be forwarded to the legal division of the bureau...

  3. 31 CFR 3.3 - Legal review.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance: Treasury 1 2012-07-01 2012-07-01 false Legal review. 3.3 Section 3.3 Money... OF DEPARTMENT OF TREASURY EMPLOYEES Claims Under the Federal Tort Claims Act § 3.3 Legal review. Any... that is likely to result in multiple claimants, shall be forwarded to the legal division of the bureau...

  4. 31 CFR 3.3 - Legal review.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance: Treasury 1 2011-07-01 2011-07-01 false Legal review. 3.3 Section 3.3 Money... OF DEPARTMENT OF TREASURY EMPLOYEES Claims Under the Federal Tort Claims Act § 3.3 Legal review. Any... that is likely to result in multiple claimants, shall be forwarded to the legal division of the bureau...

  5. 31 CFR 3.3 - Legal review.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Legal review. 3.3 Section 3.3 Money... OF DEPARTMENT OF TREASURY EMPLOYEES Claims Under the Federal Tort Claims Act § 3.3 Legal review. Any... that is likely to result in multiple claimants, shall be forwarded to the legal division of the bureau...

  6. 31 CFR 3.3 - Legal review.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance: Treasury 1 2013-07-01 2013-07-01 false Legal review. 3.3 Section 3.3 Money... OF DEPARTMENT OF TREASURY EMPLOYEES Claims Under the Federal Tort Claims Act § 3.3 Legal review. Any... that is likely to result in multiple claimants, shall be forwarded to the legal division of the bureau...

  7. Ultraviolet and near-infrared luminescence of LaBO3:Ce3+,Yb3+

    NASA Astrophysics Data System (ADS)

    Wei, Heng-Wei; Shao, Li-Ming; Jiao, Huan; Jing, Xi-Ping

    2018-01-01

    Ce3+ or Yb3+ singly doped LaBO3 and Ce3+-Yb3+ co-doped LaBO3 were prepared by conventional solid state reactions at 1100 °C and their photoluminescence (PL) properties were investigated. The emission spectrum of LaBO3:Ce3+,Yb3+ contains both the Ce3+ ultraviolet (UV) emissions (355 nm and 380 nm) and the Yb3+ near infrared (NIR) emission (975 nm) when excited by the UV light at 270 nm. By using the data of the Ce3+ decay curves and the PL intensities of both Ce3+ and Yb3+, the energy transfer efficiency (η) from Ce3+ to Yb3+, the actual energy transfer efficiency (AE) and the quantum efficiency (Q) of the Yb3+ emission were calculated. In the Ce3+-Yb3+ co-doped LaBO3, Ce3+ can transfer its absorbed energy to Yb3+ efficiently (η can be over 60%), and Yb3+ shows the Q value over 50% when it accepts the energy from Ce3+, which results in the low AE value ∼30%. The energy transfer process from Ce3+ to Yb3+ may be understood by the charge transfer mechanism: Ce3+ + Yb3+ ↔ Ce4+ + Yb2+. Particularly the Ce3+-Yb3+ co-doped LaBO3 phosphor gives the emissions mainly in the UV range and the NIR range with a portion of visible emissions in eye-insensitive range. This unique property may be suitable for applications in anti-counterfeiting techniques and public security affairs.

  8. Solubility of SC2O3 in NA3ALF6-K3ALF6-ALF3 Melts

    NASA Astrophysics Data System (ADS)

    Tian, Zhongliang; Hu, Xun; Lai, Yanqing; Yang, Shu; Ye, Shaolong; Li, Jie

    The electrolyte with high solubility for Sc2O3 is very important to realize the preparation of Al-Sc master alloy by the molten salt electrolysis. The solubility of Sc2O3 in K3AlF6-Na3AlF6-AlF3 melts is determined with an isothermal saturation method. The effects of KR (ratio of K3AlF6 to K3AlF6+Na3AlF6), the concentration of Al2O3 and the temperature on the solubility of Sc2O3 are also investigated. The results indicate that the solubility of Sc2O3 in K3AlF6-Na3AlF6-AlF3 melts increases and then decreases with KR increasing. The solubility of Sc2O3 is 8.698 wt.% in (K3AlF6-Na3AlF6)(KR25%)-18 wt.%AlF3 melts at 940°C. The effect of temperature on the solubility is little, and the values are 8.575 wt.% and 8.762 wt.% respectively when the temperatures are 930°C and 960°C. The solubility decreases from 8.809 wt.% to 7.058 wt.% as the concentration of Al2O3 increases from 1.5 wt.% to 5.0 wt.% at 950°C.

  9. Prediction on electronic structure of CH3NH3PbI3/Fe3O4 interfaces

    NASA Astrophysics Data System (ADS)

    Hou, Xueyao; Wang, Xiaocha; Mi, Wenbo; Du, Zunfeng

    2018-01-01

    The interfacial electronic structures of CH3NH3PbI3(MAPbI3)/Fe3O4 heterostructures are predicted by density functional theory. Four models (MAI/FeBO, PbI2/FeBO, MAI/FeA and PbI2/FeA) are included. Especially, a half-metal to semiconductor transition of Fe3O4 appears in PbI2/FeA model. A series of electric field is added to PbI2/FeA model, and a direct-indirect bandgap transition of Fe3O4 appears at a 500-kV/cm field. The electric field can control the bandgap of Fe3O4 in PbI2/FeA model by modulating the hybridization. The prediction of spin-related bandgap characteristic in MAPbI3/Fe3O4 is meaningful for further study.

  10. Block of high-threshold calcium channels by the synthetic polyamines sFTX-3.3 and FTX-3.3.

    PubMed

    Norris, T M; Moya, E; Blagbrough, I S; Adams, M E

    1996-10-01

    A polyamine component of Agelenopsis aperta spider venom designated FTX is reported to be a selective antagonist of P-type calcium channels in the mammalian brain. Consequently, this component has frequently been used as a pharmacological tool to determine the presence, distribution, and function of P-type channels in physiological systems. We describe antagonism of calcium channels by the synthesized polyamine FTX-3.3, which has the proposed structure of natural FTX. We also examined a corresponding polyamine amide, sFTX-3.3. These polyamines are critically evaluated for antagonism of three high-threshold calcium channel subtypes in rat neurons through the use of the whole-cell patch-clamp technique. FTX-3.3 (IC50 = approximately 0.13 mM) is approximately twice as potent as sFTX-3.3 (IC50 = approximately 0.24 mM) against P-type channels and approximately 3-fold more potent against N-type channels (FTX-3.3, IC50 = approximately 0.24 mM; sFTX-3.3, IC50 = approximately 0.70 mM). Both polyamines also block L-type calcium channels with similar potencies. sFTX-3.3 (1 mM) and FTX-3.3 (0.5 mM) typically block 50% and 65% of Bay K8644-enhanced L-type current, respectively. Antagonism of each calcium channel subtype is voltage dependent, with less inhibition of Ba2+ currents at more-positive potentials. These data show that both sFTX-3.3 and FTX-3.3 antagonize P-, N-, and L-type calcium channels in mammalian Purkinje and superior cervical ganglia neurons with similar IC50 values.

  11. In vitro assessment of soybean lecithin and egg yolk based diluents for cryopreservation of goat semen.

    PubMed

    Salmani, Hossein; Towhidi, Armin; Zhandi, Mahdi; Bahreini, Majid; Sharafi, Mohsen

    2014-04-01

    Soybean lecithin is a suitable plant-based cryoprotectant for freezing ruminant sperm. Optimum level of lecithin was not clear for goat semen cryopreservation. The objective of this study was to investigate the effects of different levels of soybean lecithin in semen extender on post-thaw sperm quality including CASA-motion parameters, viability, plasma membrane integrity and lipid peroxidation. Semen samples were collected from 4 Mahabadi bucks using an artificial vagina. Different concentrations of soy lecithin (SL, 0.5%, 1%, 1.5%, 2% and 2.5% w/v) were compared to 15% (v/v) egg yolk-based extender (TR-EY). No significant difference was observed for sperm progressive motility, viability or plasma membrane integrity in 1.5% SL media (33.8%, 66%, and 62.7%, respectively) and TR-EY medium (35.4%, 67.2%, and 64.9%, respectively). Sperm motion characteristics (VAP, VSL, VCL, ALH and LIN) and rapid spermatozoa were improved with extender containing 1% and 1.5% SL, compared to TR-EY extender. Furthermore, egg yolk produced significantly higher malondialdehyde (4.02±0.21) than other groups. Results suggest that the optimal lecithin concentration in the semen extender was 1.5% and also soy lecithin can substitute for egg yolk during cryopreservation for caprine sperm. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Heavily-hydrated lithic clasts in CH chondrites and the related, metal-rich chondrites Queen Alexandra Range 94411 and Hammadah al Hamra 237

    NASA Astrophysics Data System (ADS)

    Greshake, A.; Krot, A. N.; Meibom, A.; Weisberg, M. K.; Zolensky, M. E.; Keil, K.

    2002-02-01

    Fine-grained, heavily-hydrated lithic clasts in the metal-rich (CB) chondrites Queen Alexandra Range (QUE) 94411 and Hammadah al Hamra 237 and CH chondrites, such as Patuxent Range (PAT) 91546 and Allan Hills (ALH) 85085, are mineralogically similar suggesting genetic relationship between these meteorites. These clasts contain no anhydrous silicates and consist of framboidal and platelet magnetite, prismatic sulfides (pentlandite and pyrrhotite), and Fe-Mn-Mg-bearing Ca-carbonates set in a phyllosilicate-rich matrix. Two types of phyllosilicates were identified: serpentine, with basal spacing of ?0.73 nm, and saponite, with basal spacings of about 1.1-1.2 nm. Chondrules and FeNi-metal grains in CB and CH chondrites are believed to have formed at high temperature (>1300 K) by condensation in a solar nebula region that experienced complete vaporization. The absence of aqueous alteration of chondrules and metal grains in CB and CH chondrites indicates that the clasts experienced hydration in an asteroidal setting prior to incorporation into the CH and CB parent bodies. The hydrated clasts were either incorporated during regolith gardening or accreted together with chondrules and FeNi-metal grains after these high-temperature components had been transported from their hot formation region to a much colder region of the solar nebula.

  13. 2,4-Bis(3-methoxy-phen-yl)-3-aza-bicyclo-[3.3.1]nonan-9-one.

    PubMed

    Parthiban, P; Ramkumar, V; Jeong, Yeon Tae

    2009-12-04

    In the crystal structure, the title compound, C(22)H(25)NO(3), exists in a twin-chair conformation with equatorial orientations of the meta-methoxy-phenyl groups on both sides of the secondary amino group. The title compound is a positional isomer of 2,4-bis-(2-methoxy-phen-yl)-3-aza-bicyclo-[3.3.1]nonan-9-one and 2,4-bis-(4-methoxy-phen-yl)-3-aza-bicyclo-[3.3.1]nonan-9-one, which both also exhibit twin-chair conformations with equatorial dispositions of the anisyl rings on both sides of the secondary amino group. In the title compound, the meta-methoxy-phenyl rings are orientated at an angle of 25.02 (3)° with respect to each other, whereas in the ortho and para isomers, the anisyl rings are orientated at dihedral angles of 33.86 (3) and 37.43 (4)°, respectively. The crystal packing is dominated by van der Waals inter-actions and by an inter-molecular N-H⋯O hydrogen bond, whereas in the ortho isomer, an inter-molecular N-H⋯π inter-action (H⋯Cg = 2.75 Å) is found.

  14. Copolyimides Prepared from 3,4'-Oxydianiline and 1,3-Bis(3-Aminophenoxy) Benzene with 3,3', 4,4'-Biphenylcarboxylic Dianhydride

    NASA Technical Reports Server (NTRS)

    Jensen, Brian J. (Inventor)

    1999-01-01

    Polyimide copolymers were prepared by reacting different ratios of 3,4'-oxydianiline (ODA) and 1,3-bis(3- aminophenoxy)benzene (APB) with 3,3',4,4'- biphenylcarboxylic dianhydride (BPDA) and endcappfng with an effective amount of a non-reactive endcapper. Within a narrow ratio of diamines, from -50% ODA/50% APB to -95% ODA/5% APB, the copolyimides prepared with BPDA have a unique combination of properties that make them very attractive for various applications. This unique combination of properties includes low pressure processing (200 psi and below), long term melt stability (several hours at 390 C.), improved toughness, improved solvent resistance, improved adhesive properties, and improved composite mechanical properties.

  15. Enhanced Performance of Perovskite CH3NH3PbI3 Solar Cell by Using CH3NH3I as Additive in Sequential Deposition.

    PubMed

    Xie, Yian; Shao, Feng; Wang, Yaoming; Xu, Tao; Wang, Deliang; Huang, Fuqiang

    2015-06-17

    Sequential deposition is a widely adopted method to prepare CH3NH3PbI3 on mesostructured TiO2 electrode for organic lead halide perovskite solar cells. However, this method often suffers from the uncontrollable crystal size, surface morphology, and residual PbI2 in the resulting CH3NH3PbI3, which are all detrimental to the device performance. We herein present an optimized sequential solution deposition method by introducing different amount of CH3NH3I in PbI2 precursor solution in the first step to prepare CH3NH3PbI3 absorber on mesoporous TiO2 substrates. The addition of CH3NH3I in PbI2 precursor solution can affect the crystallization and composition of PbI2 raw films, resulting in the variation of UV-vis absorption and surface morphology. Proper addition of CH3NH3I not only enhances the absorption but also improves the efficiency of CH3NH3PbI3 solar cells from 11.13% to 13.37%. Photoluminescence spectra suggest that the improvement of device performance is attributed to the decrease of recombination rate of carriers in CH3NH3PbI3 absorber. This current method provides a highly repeatable route for enhancing the efficiency of CH3NH3PbI3 solar cell in the sequential solution deposition method.

  16. Photoelectric characteristics of CH3NH3PbI3/p-Si heterojunction

    NASA Astrophysics Data System (ADS)

    Yamei, Wu; Ruixia, Yang; Hanmin, Tian; Shuai, Chen

    2016-05-01

    Organic-inorganic hybrid perovskite CH3NH3PbI3 film is prepared on p-type silicon substrate using the one-step solution method to form a CH3NH3PbI3/p-Si heterojunction. The film morphology and structure are characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The photoelectric properties of the CH3NH3PbI3/p-Si heterojunction are studied by testing the current-voltage (I-V) with and without illumination and capacitance-voltage (C-V) characteristics. It turns out from the I-V curve without illumination that the CH3NH3PbI3/p-Si heterojunction has a rectifier feature with the rectification ratio over 70 at the bias of ±5 V. Also, there appears a photoelectric conversion phenomenon on this heterojunction with a short circuit current (Isc) of 0.16 μA and an open circuit voltage (Voc) of about 10 mV The high frequency C-V characteristic of the Ag/CH3NH3PbI3/p-Si heterojunction turns out to be similar to that of the metal-insulator-semiconductor (MIS) structure, and a parallel translation of the C-V curve along the forward voltage axis is found. This parallel translation means the existence of defects at the CH3NH3PbI3/p-Si interface and positive fixed charges in the CH3NH3PbI3 layer. The defects at the interface of the CH3NH3PbI3/p-Si heterojunction result in the dramatic decline of the Voc. Besides, the C-V test of CH3NH3PbI3 film shows a non-linear dielectric property and the dielectric value is about 4.64 as calculated. Project supported by the Hebei Province Natural Science Foundation of China (No. F2014202184) and the Tianjin Natural Science Foundation of China (No. 15JCZDJC37800).

  17. Addition of NH{sub 3} to Al{sub 3}O{sub 3}{sup -}

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

    Wyrwas, Richard B.; Jarrold, Caroline Chick; Das, Ujjal

    2006-05-28

    Recent computational studies on the addition of ammonia (NH{sub 3}) to the Al{sub 3}O{sub 3}{sup -} cluster anion [A. Guevara-Garcia, A. Martinez, and J. V. Ortiz, J. Chem. Phys. 122, 214309 (2005)] have motivated experimental and additional computational studies, reported here. Al{sub 3}O{sub 3}{sup -} is observed to react with a single NH{sub 3} molecule to form the Al{sub 3}O{sub 3}NH{sub 3}{sup -} ion in mass spectrometric studies. This is in contrast to similarly performed studies with water, in which the Al{sub 3}O{sub 5}H{sub 4}{sup -} product was highly favored. However, the anion PE spectrum of the ammoniated species ismore » very similar to that of Al{sub 3}O{sub 4}H{sub 2}{sup -}. The adiabatic electron affinity of Al{sub 3}O{sub 3}NH{sub 3} is determined to be 2.35(5) eV. Based on comparison between the spectra and calculated electron affinities, it appears that NH{sub 3} adds dissociatively to Al{sub 3}O{sub 3}{sup -}, suggesting that the time for the Al{sub 3}O{sub 3}{sup -}{center_dot}NH{sub 3} complex to either overcome or tunnel through the barrier to proton transfer (which is higher for NH{sub 3} than for water) is short relative to the time for collisional cooling in the experiment.« less

  18. NH{sub 3}(3,3) AND CH{sub 3}OH NEAR SUPERNOVA REMNANTS: GBT AND VLA OBSERVATIONS

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

    McEwen, Bridget C.; Pihlström, Ylva M.; Sjouwerman, Loránt O.

    2016-08-01

    We report on Green Bank Telescope 23.87 GHz NH{sub 3}(3,3) emission observations in five supernova remnants (SNRs) interacting with molecular clouds (G1.4−0.1, IC 443, W44, W51C, and G5.7−0.0). The observations show a clumpy gas density distribution, and in most cases the narrow line widths of ∼3–4 km s{sup −1} are suggestive of maser emission. Very Large Array observations reveal 36 and/or 44 GHz CH{sub 3}OH maser emission in a majority (72%) of the NH{sub 3} peak positions toward three of these SNRs. This good positional correlation is in agreement with the high densities required for the excitation of each line.more » Through these observations we have shown that CH{sub 3}OH and NH{sub 3} maser emission can be used as indicators of high-density clumps of gas shocked by SNRs, and provide density estimates thereof. Modeling of the optical depth of the NH{sub 3}(3,3) emission is compared to that of CH{sub 3}OH, constraining the densities of the clumps to a typical density of the order of 10{sup 5} cm{sup −3} for cospatial masers. Regions of gas with this density are found to exist in the post-shocked gas quite close to the SNR shock front, and may be associated with sites where cosmic rays produce gamma-ray emission via neutral pion decay.« less

  19. 48 CFR 3.908-3 - Policy.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Policy. 3.908-3 Section 3.908-3 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION GENERAL IMPROPER BUSINESS... Policy. (a) Contractors and subcontractors are prohibited from discharging, demoting, or otherwise...

  20. 47 CFR 15.251 - Operation within the bands 2.9-3.26 GHz, 3.267-3.332 GHz, 3.339-3.3458 GHz, and 3.358-3.6 GHz.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... exceed 3000 microvolts/meter/MHz at 3 meters in any direction. Further, an AVIS, when in its operating position, shall not produce a field strength greater than 400 microvolts/meter/MHz at 3 meters in any... maximum of 100 microvolts/meter/MHz at 3 meters, measured from 30 MHz to 20 GHz for the complete system...

  1. Energy transfer and tunable multicolor emission and paramagnetic properties of GdF3:Dy(3+),Tb(3+),Eu(3+) phosphors.

    PubMed

    Guan, Hongxia; Sheng, Ye; Xu, Chengyi; Dai, Yunzhi; Xie, Xiaoming; Zou, Haifeng

    2016-07-20

    A series of Dy(3+), Tb(3+), Eu(3+) singly or doubly or triply doped GdF3 phosphors were synthesized by a glutamic acid assisted one-step hydrothermal method. The samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and photoluminescence (PL) spectroscopy. The results show that the synthesized samples are all pure GdF3. The obtained samples have a peanut-like morphology with a diameter of about 270 nm and a length of about 600 nm. Under UV excitation, GdF3:Dy(3+), GdF3:Tb(3+) and GdF3:Eu(3+) samples exhibit strong blue, green and red emissions, respectively. By adjusting their relative doping concentrations in the GdF3 host, the different color hues of green and red light are obtained by co-doped Dy(3+), Tb(3+) and Tb(3+), Eu(3+) ions in the GdF3 host, respectively. Besides, there exist two energy transfer pairs in the GdF3 host: (1) Dy(3+) → Tb(3+) and (2) Tb(3+) → Eu(3+). More significantly, in the Dy(3+), Tb(3+), and Eu(3+) tri-doped GdF3 phosphors, white light can also be achieved upon excitation of UV light by adjusting the doping concentration of Eu(3+). In addition, the obtained samples also exhibit paramagnetic properties at room temperature (300 K) and low temperature (2 K). It is obvious that multifunctional Dy(3+), Tb(3+), Eu(3+) tri-doped GdF3 materials including tunable multicolors and intrinsic paramagnetic properties may have potential applications in the field of full-color displays.

  2. Host-Sensitized and Tunable Luminescence of GdNbO4:Ln3+ (Ln3+ = Eu3+/Tb3+/Tm3+) Nanocrystalline Phosphors with Abundant Color.

    PubMed

    Liu, Xiaoming; Chen, Chen; Li, Shuailong; Dai, Yuhua; Guo, Huiqin; Tang, Xinghua; Xie, Yu; Yan, Liushui

    2016-10-17

    Up to now, GdNbO 4 has always been regarded as an essentially inert material in the visible region with excitation of UV light and electron beams. Nevertheless, here we demonstrate a new recreating blue emission of GdNbO 4 nanocrystalline phosphors with a quantum efficiency of 41.6% and host sensitized luminescence in GdNbO 4 :Ln 3+ (Ln 3+ = Eu 3+ /Tb 3+ /Tm 3+ ) nanocrystalline phosphors with abundant color in response to UV light and electron beams. The GdNbO 4 and GdNbO 4 :Ln 3+ (Ln 3+ = Eu 3+ /Tb 3+ /Tm 3+ ) nanocrystalline phosphors were synthesized by a Pechini-type sol-gel process. With excitation of UV light and low-voltage electron beams, the obtained GdNbO 4 nanocrystalline phosphor presents a strong blue luminescence from 280 to 650 nm centered around 440 nm, and the GdNbO 4 :Ln 3+ nanocrystalline phosphors show both host emission and respective emission lines derived from the characterize f-f transitions of the doping Eu 3+ , Tb 3+ , and Tm 3+ ions. The luminescence color of GdNbO 4 :Ln 3+ nanocrystalline phosphors can be tuned from blue to green, red, blue-green, orange, pinkish, white, etc. by varying the doping species, concentration, and relative ratio of the codoping rare earth ions in GdNbO 4 host lattice. A single-phase white-light-emission has been realized in Eu 3+ /Tb 3+ /Tm 3+ triply doped GdNbO 4 nanocrystalline phosphors. The luminescence properties and mechanisms of GdNbO 4 and GdNbO 4 :Ln 3+ (Ln 3+ = Eu 3+ /Tb 3+ /Tm 3+ ) are updated.

  3. Synthesis of the water soluble ligands dmPTA and dmoPTA and the complex [RuClCp(HdmoPTA)(PPh(3))](OSO(2)CF(3)) (dmPTA = N,N'-Dimethyl-1,3,5-triaza-7-phosphaadamantane, dmoPTA = 3,7-Dimethyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane, HdmoPTA = 3,7-H-3,7-Dimethyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane).

    PubMed

    Mena-Cruz, Adrian; Lorenzo-Luis, Pablo; Romerosa, Antonio; Saoud, Mustapha; Serrano-Ruiz, Manuel

    2007-07-23

    The new water-soluble ligand dmPTA(OSO(2)CF(3))(2) (1) (dmPTA = N,N'-dimethyl-1,3,5-triaza-7-phosphaadamantane) has been synthesized by reaction of PTA with MeOSO(2)CF(3) in acetone (PTA = 1,3,5-triaza-7-phosphatricycle[3.3.1.1(3,7)]decane). The reaction of 1 with KOH gave rise to the new water-soluble ligand dmoPTA (3) (dmoPTA = 3,7-dimethyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane) by elimination of the -CH(2)- group located between both NCH(3) units. Compound dmPTA(BF(4))(2) (2) and complex [RuClCp(HdmoPTA)(PPh(3))](OSO(2)CF(3)) (4) have also been synthesized, while compounds HdmoPTA(BF(4)) (3a) and [RuClCp(dmPTA)(PPh(3))](OSO(2)CF(3)) (5) were characterized but not isolated. The new ligands and the complex have been fully characterized by NMR, IR, elemental analysis, and X-ray crystal structure determination (ligand 1 and complex 4). The synthetic processes for 3 and 4 were studied.

  4. Synthesis ofN-(2-chloro-5-methylthiophenyl)-N'-(3-methyl-thiophenyl)-N'-[3H3]methylguanidine, l brace [3H3]CNS-5161 r brace

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

    Gibbs, Andrew R.; Morimoto, Hiromi; VanBrocklin, Henry F.

    2001-09-28

    The preparation of the title compound, [{sup 3}H{sub 3}]CNS-5161, was accomplished in three steps starting with the production of [{sup 3}H{sub 3}]iodomethane (CT{sub 3}I). The intermediate N-[{sup 3}H{sub 3}]methyl-3-(thiomethylphenyl)cyanamide was prepared in 77% yield by the addition of CT{sub 3}I to 3-(thiomethylphenyl)cyanamide, previously treated with sodium hydride. Reaction of this tritiated intermediate with 2-chloro-5-thiomethylaniline hydrochloride formed the guanidine compound [{sup 3}H{sub 3}]CNS-5161. Purification by HPLC gave the desired labeled product in an overall yield of 9% with greater than 96% radiochemical purity and a final specific activity of 66 Ci mmol{sup -1}.

  5. 26 CFR 3.3 - Nontaxability of deposits.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 14 2014-04-01 2013-04-01 true Nontaxability of deposits. 3.3 Section 3.3...) CAPITAL CONSTRUCTION FUND § 3.3 Nontaxability of deposits. (a) In general. Section 607(d) of the Act sets... section 607(b) and § 3.2. The specific treatment of deposits with respect to each of the subceilings is...

  6. 26 CFR 3.3 - Nontaxability of deposits.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 14 2011-04-01 2010-04-01 true Nontaxability of deposits. 3.3 Section 3.3...) CAPITAL CONSTRUCTION FUND § 3.3 Nontaxability of deposits. (a) In general. Section 607(d) of the Act sets... section 607(b) and § 3.2. The specific treatment of deposits with respect to each of the subceilings is...

  7. 26 CFR 3.3 - Nontaxability of deposits.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 14 2010-04-01 2010-04-01 false Nontaxability of deposits. 3.3 Section 3.3...) CAPITAL CONSTRUCTION FUND § 3.3 Nontaxability of deposits. (a) In general. Section 607(d) of the Act sets... section 607(b) and § 3.2. The specific treatment of deposits with respect to each of the subceilings is...

  8. 26 CFR 3.3 - Nontaxability of deposits.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 14 2012-04-01 2012-04-01 false Nontaxability of deposits. 3.3 Section 3.3...) CAPITAL CONSTRUCTION FUND § 3.3 Nontaxability of deposits. (a) In general. Section 607(d) of the Act sets... section 607(b) and § 3.2. The specific treatment of deposits with respect to each of the subceilings is...

  9. 26 CFR 3.3 - Nontaxability of deposits.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 14 2013-04-01 2013-04-01 false Nontaxability of deposits. 3.3 Section 3.3...) CAPITAL CONSTRUCTION FUND § 3.3 Nontaxability of deposits. (a) In general. Section 607(d) of the Act sets... section 607(b) and § 3.2. The specific treatment of deposits with respect to each of the subceilings is...

  10. 17 CFR 3.3 - Chief compliance officer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 17 Commodity and Securities Exchanges 1 2013-04-01 2013-04-01 false Chief compliance officer. 3.3 Section 3.3 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION REGISTRATION Registration § 3.3 Chief compliance officer. (a) Designation. Each futures commission merchant, swap dealer...

  11. 17 CFR 3.3 - Chief compliance officer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 17 Commodity and Securities Exchanges 1 2014-04-01 2014-04-01 false Chief compliance officer. 3.3 Section 3.3 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION REGISTRATION Registration § 3.3 Chief compliance officer. (a) Designation. Each futures commission merchant, swap dealer...

  12. 48 CFR 3.101-3 - Agency regulations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Agency regulations. 3.101-3 Section 3.101-3 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION GENERAL IMPROPER BUSINESS PRACTICES AND PERSONAL CONFLICTS OF INTEREST Safeguards 3.101-3 Agency regulations. (a...

  13. 48 CFR 3.101-3 - Agency regulations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Agency regulations. 3.101-3 Section 3.101-3 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION GENERAL IMPROPER BUSINESS PRACTICES AND PERSONAL CONFLICTS OF INTEREST Safeguards 3.101-3 Agency regulations. (a...

  14. 5 CFR 3.3 - Conversion of appointments.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 5 Administrative Personnel 1 2014-01-01 2014-01-01 false Conversion of appointments. 3.3 Section 3.3 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE RULES NONCOMPETITIVE ACQUISITION OF STATUS (RULE III) § 3.3 Conversion of appointments. Any person who acquires a competitive...

  15. 5 CFR 3.3 - Conversion of appointments.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 5 Administrative Personnel 1 2013-01-01 2013-01-01 false Conversion of appointments. 3.3 Section 3.3 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE RULES NONCOMPETITIVE ACQUISITION OF STATUS (RULE III) § 3.3 Conversion of appointments. Any person who acquires a competitive...

  16. 5 CFR 3.3 - Conversion of appointments.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 5 Administrative Personnel 1 2012-01-01 2012-01-01 false Conversion of appointments. 3.3 Section 3.3 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE RULES NONCOMPETITIVE ACQUISITION OF STATUS (RULE III) § 3.3 Conversion of appointments. Any person who acquires a competitive...

  17. 5 CFR 3.3 - Conversion of appointments.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Conversion of appointments. 3.3 Section 3.3 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE RULES NONCOMPETITIVE ACQUISITION OF STATUS (RULE III) § 3.3 Conversion of appointments. Any person who acquires a competitive...

  18. 5 CFR 3.3 - Conversion of appointments.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Conversion of appointments. 3.3 Section 3.3 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE RULES NONCOMPETITIVE ACQUISITION OF STATUS (RULE III) § 3.3 Conversion of appointments. Any person who acquires a competitive...

  19. 38 CFR 3.18-3.19 - [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2011-07-01 2011-07-01 false [Reserved] 3.18-3.19 Section 3.18-3.19 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation General §§ 3.18-3.19 [Reserved] ...

  20. 38 CFR 3.18-3.19 - [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2013-07-01 2013-07-01 false [Reserved] 3.18-3.19 Section 3.18-3.19 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation General §§ 3.18-3.19 [Reserved] ...

  1. 38 CFR 3.18-3.19 - [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2014-07-01 2014-07-01 false [Reserved] 3.18-3.19 Section 3.18-3.19 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation General §§ 3.18-3.19 [Reserved] ...

  2. 38 CFR 3.18-3.19 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false [Reserved] 3.18-3.19 Section 3.18-3.19 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation General §§ 3.18-3.19 [Reserved] ...

  3. 38 CFR 3.18-3.19 - [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2012-07-01 2012-07-01 false [Reserved] 3.18-3.19 Section 3.18-3.19 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation General §§ 3.18-3.19 [Reserved] ...

  4. 12 CFR 3.12-3.19 - [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 1 2014-01-01 2014-01-01 false [Reserved] 3.12-3.19 Section 3.12-3.19 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY CAPITAL ADEQUACY STANDARDS Capital Ratio Requirements and Buffers §§ 3.12-3.19 [Reserved] ...

  5. 43 CFR 3410.3-3 - Operating regulations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Operating regulations. 3410.3-3 Section 3410.3-3 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND... § 3410.3-3 Operating regulations. The licensee shall comply with the provisions of the operating...

  6. Correlations for the Viscosity of 2,3,3,3-Tetrafluoroprop-1-ene (R1234yf) and trans-1,3,3,3-Tetrafluoropropene (R1234ze(E))†

    PubMed Central

    Huber, Marcia L.; Assael, Marc J.

    2016-01-01

    Due to concerns about global warming, there is interest in 2,3,3,3-Tetrafluoroprop-1-ene (R1234yf) and trans-1,3,3,3-Tetrafluoropropene (R1234ze(E)) as potential replacements for refrigerants with high global warming potential (GWP). In this manuscript we survey available data and provide viscosity correlations that cover the entire fluid range including vapor, liquid, and supercritical regions. The correlation for R1234yf is valid from the triple point (220 K) to 410 K at pressures up to 30 MPa, and the correlation for R1234ze(E) is valid from the triple point (169 K) to 420 K at pressures up to 100 MPa. The estimated uncertainty for both correlations at a 95 % confidence level is 2 % for the liquid phase over the temperature range 243 K to 363 K at pressures to 30 MPa, and 3 % for the gas phase at atmospheric pressure. PMID:27840461

  7. 38 CFR 3.253-3.255 - [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2014-07-01 2014-07-01 false [Reserved] 3.253-3.255 Section 3.253-3.255 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation Dependency, Income and Estate §§ 3.253-3...

  8. 38 CFR 3.253-3.255 - [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2013-07-01 2013-07-01 false [Reserved] 3.253-3.255 Section 3.253-3.255 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation Dependency, Income and Estate §§ 3.253-3...

  9. 38 CFR 3.253-3.255 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false [Reserved] 3.253-3.255 Section 3.253-3.255 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation Dependency, Income and Estate §§ 3.253-3...

  10. 38 CFR 3.258-3.259 - [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2011-07-01 2011-07-01 false [Reserved] 3.258-3.259 Section 3.258-3.259 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation Dependency, Income and Estate §§ 3.258-3...

  11. 38 CFR 3.253-3.255 - [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2012-07-01 2012-07-01 false [Reserved] 3.253-3.255 Section 3.253-3.255 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation Dependency, Income and Estate §§ 3.253-3...

  12. 38 CFR 3.258-3.259 - [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false [Reserved] 3.258-3.259 Section 3.258-3.259 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation Dependency, Income and Estate §§ 3.258-3...

  13. 38 CFR 3.258-3.259 - [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2013-07-01 2013-07-01 false [Reserved] 3.258-3.259 Section 3.258-3.259 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation Dependency, Income and Estate §§ 3.258-3...

  14. 38 CFR 3.253-3.255 - [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2011-07-01 2011-07-01 false [Reserved] 3.253-3.255 Section 3.253-3.255 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation Dependency, Income and Estate §§ 3.253-3...

  15. 38 CFR 3.258-3.259 - [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2012-07-01 2012-07-01 false [Reserved] 3.258-3.259 Section 3.258-3.259 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation Dependency, Income and Estate §§ 3.258-3...

  16. 38 CFR 3.258-3.259 - [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2014-07-01 2014-07-01 false [Reserved] 3.258-3.259 Section 3.258-3.259 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS ADJUDICATION Pension, Compensation, and Dependency and Indemnity Compensation Dependency, Income and Estate §§ 3.258-3...

  17. 10 CFR 960.3-1-3 - Regionality.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Regionality. 960.3-1-3 Section 960.3-1-3 Energy DEPARTMENT OF ENERGY GENERAL GUIDELINES FOR THE PRELIMINARY SCREENING OF POTENTIAL SITES FOR A NUCLEAR WASTE REPOSITORY Implementation Guidelines § 960.3-1-3 Regionality. In making site recommendations for repository...

  18. 10 CFR 960.3-1-3 - Regionality.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Regionality. 960.3-1-3 Section 960.3-1-3 Energy DEPARTMENT OF ENERGY GENERAL GUIDELINES FOR THE PRELIMINARY SCREENING OF POTENTIAL SITES FOR A NUCLEAR WASTE REPOSITORY Implementation Guidelines § 960.3-1-3 Regionality. In making site recommendations for repository...

  19. 10 CFR 960.3-1-3 - Regionality.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Regionality. 960.3-1-3 Section 960.3-1-3 Energy DEPARTMENT OF ENERGY GENERAL GUIDELINES FOR THE PRELIMINARY SCREENING OF POTENTIAL SITES FOR A NUCLEAR WASTE REPOSITORY Implementation Guidelines § 960.3-1-3 Regionality. In making site recommendations for repository...

  20. 10 CFR 960.3-1-3 - Regionality.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Regionality. 960.3-1-3 Section 960.3-1-3 Energy DEPARTMENT OF ENERGY GENERAL GUIDELINES FOR THE PRELIMINARY SCREENING OF POTENTIAL SITES FOR A NUCLEAR WASTE REPOSITORY Implementation Guidelines § 960.3-1-3 Regionality. In making site recommendations for repository...

  1. Water Remedial Investigation Report, Version 3.3. Volume 3

    DTIC Science & Technology

    1989-07-01

    26084 ,.6085,26086, .6088,61627,26129 ,261.3,26.0 ,2 142 ,2 1147 27 27001 , 27002�, 27005, 27016, 27024, 27026, 27028, 27030, 27031, 27040, 27049...0.115 - 1.220 0 -- 2, Confined 28 1 0.058 I 40.300 3, Unconfined 4 0 -- 0 -- 3, Confined 20 I 0.162 I ɘ ISO 4, Unconfined 0 0 -- 0 -- 4, Confined 19...monitoring event in Sections 2, 23, 24, 27 and 34, and in the northern off-post area (Figure 4.2-8). These iso !-ted detections, except for those noted in

  2. The ν 3 and 2ν 3 bands of 32S 16O 3, 32S 18O 3, 34S 16O 3, and 34S 18O 3

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

    Sharpe, Steven W.; Blake, Thomas A.; Sams, Robert L.

    2003-12-01

    The fifth of a series of publications on the high resolution rotation-vibration spectra of sulfur trioxide reports the results of a systematic study of the v3(é) and 2v3(A1'+E') infrared bands of the four symmetric top isotopomers 32S 16O 3, 34S 16O 3, 32S 18O 3, and 34S 18O 3. An internal coupling between the l = 0 and l = +2 levels of the 2v3 (A1'+E') states was observed. This small perturbation results in a level crossing between K-l = 9 and 12, in consequence of which the band origins of the A1', l=0 “ghost” states could be determined tomore » a high degree of accuracy. Ground and upper state rotational as well as vibrational anharmonicity constants are reported. The constants for the center-of-mass substituted species 32S 16O 3 and 34S 16O 3 vary only slightly, as do the constants for the 32S 18O 3, 34S 18O 3 pair. The S-O bond lengths for the vibrational ground states of the species 32S 16O 3, 34S 16O 3, 32S 18O 3 and 34S 18O 3, are, respectively, 141.981992(6), 141.979412(20), 150.605240(73), and 150.602348(73) pm, where the uncertainties, given in parentheses, are two standard deviations and refer to the last digits of the associated quantity.« less

  3. CH3NH3PbI3 perovskites: Ferroelasticity revealed.

    PubMed

    Strelcov, Evgheni; Dong, Qingfeng; Li, Tao; Chae, Jungseok; Shao, Yuchuan; Deng, Yehao; Gruverman, Alexei; Huang, Jinsong; Centrone, Andrea

    2017-04-01

    Ferroelectricity has been proposed as a plausible mechanism to explain the high photovoltaic conversion efficiency in organic-inorganic perovskites; however, convincing experimental evidence in support of this hypothesis is still missing. Identifying and distinguishing ferroelectricity from other properties, such as piezoelectricity, ferroelasticity, etc., is typically nontrivial because these phenomena can coexist in many materials. In this work, a combination of microscopic and nanoscale techniques provides solid evidence for the existence of ferroelastic domains in both CH 3 NH 3 PbI 3 polycrystalline films and single crystals in the pristine state and under applied stress. Experiments show that the configuration of CH 3 NH 3 PbI 3 ferroelastic domains in single crystals and polycrystalline films can be controlled with applied stress, suggesting that strain engineering may be used to tune the properties of this material. No evidence of concomitant ferroelectricity was observed. Because grain boundaries have an impact on the long-term stability of organic-inorganic perovskite devices, and because the ferroelastic domain boundaries may differ from regular grain boundaries, the discovery of ferroelasticity provides a new variable to consider in the quest for improving their stability and enabling their widespread adoption.

  4. 40 CFR 257.3-3 - Surface water.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Surface water. 257.3-3 Section 257.3-3... and Practices § 257.3-3 Surface water. (a) For purposes of section 4004(a) of the Act, a facility... Water Act, as amended. (b) For purposes of section 4004(a) of the Act, a facility shall not cause a...

  5. 40 CFR 257.3-3 - Surface water.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Surface water. 257.3-3 Section 257.3-3... and Practices § 257.3-3 Surface water. (a) For purposes of section 4004(a) of the Act, a facility... Water Act, as amended. (b) For purposes of section 4004(a) of the Act, a facility shall not cause a...

  6. 40 CFR 257.3-3 - Surface water.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Surface water. 257.3-3 Section 257.3-3... and Practices § 257.3-3 Surface water. (a) For purposes of section 4004(a) of the Act, a facility... Water Act, as amended. (b) For purposes of section 4004(a) of the Act, a facility shall not cause a...

  7. 40 CFR 257.3-3 - Surface water.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Surface water. 257.3-3 Section 257.3-3... and Practices § 257.3-3 Surface water. (a) For purposes of section 4004(a) of the Act, a facility... Water Act, as amended. (b) For purposes of section 4004(a) of the Act, a facility shall not cause a...

  8. 40 CFR 257.3-3 - Surface water.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Surface water. 257.3-3 Section 257.3-3... and Practices § 257.3-3 Surface water. (a) For purposes of section 4004(a) of the Act, a facility... Water Act, as amended. (b) For purposes of section 4004(a) of the Act, a facility shall not cause a...

  9. The photoluminescent properties of Y2O3:Bi3+, Eu3+, Dy3+ phosphors for white-light-emitting diodes.

    PubMed

    Han, Xiumei; Feng, Xu; Qi, Xiwei; Wang, Xiaoqiang; Li, Mingya

    2014-05-01

    Bi3+, Eu3+, Dy3+ activated Y2O3 phosphors were prepared through the sol-gel process. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectra, and photoluminescence (PL) spectra were used to characterize the resulting phosphors. The XRD patterns show the refined crystal structure of Y2O3. The energy transfer processes of Bi(3+)-Eu3+ occurred in the host lattices. The thermal stability of Y2O3:Bi3+, Eu3+, Dy3+ phosphors was studied. Under short wavelength UV excitation, the phosphors show excellent characteristic red, blue, and yellow emission with medium intensity.

  10. The Influence of Layer Thickness-Ratio on Magnetoresistance in La2/3Ca1/3MnO3/La1/3Ca2/3MnO3 Exchange Biased System

    NASA Astrophysics Data System (ADS)

    Gomez, Maria Elena; Milena Diez, Sandra; Cuartas, Lina Maria; Marin, Lorena; Prieto, Pedro

    2012-02-01

    Isothermal magnetic field dependence of the resistance in La2/3Ca1/3MnO3 (F-LCMO)/ La1/3Ca2/3MnO3(AF-LCMO) bilayer and AF-LCMO/F-LCMO/AF-LCMO trilayer at temperatures below N'eel temperature of the antiferromagnetic layer were carried out to study the thickness layers influence on magneto transport properties. We grew multilayers using a high oxygen pressure sputtering technique. We systematically varied the thickness of the F-LCMO layer, tF, maintaining constant the thickness of the AF-LCMO layer, tAF. We studied the influence of the thickness ratio tF/tAF on the ZFC and FC magnetoresistance (MR) loops. HFC was varied from 100 Oe to 400 Oe. We found that MR has hysteretic behavior as observed in [La2/3Ca1/3MnO3/La1/3Ca2/3MnO3]N superlattices, where MR increases with the increasing field from H=0 to a maximum and then it decreases continuously. The position and magnitude of the maximum is not symmetric with respect to the axis H=0 for both FC and ZFC loops. We found that magnetoresistance behavior of the bilayer and trilayer is thickness-ratio dependent for both ZFC and FC loops.

  11. Luminescence and energy transfer properties of Ca2Ba3(PO4)3Cl and Ca2Ba3(PO4)3Cl:A (A = Eu2+/Ce3+/Dy3+/Tb3+) under UV and low-voltage electron beam excitation.

    PubMed

    Shang, Mengmeng; Geng, Dongling; Yang, Dongmei; Kang, Xiaojiao; Zhang, Yang; Lin, Jun

    2013-03-18

    Pure Ca2Ba3(PO4)3Cl and rare earth ion (Eu(2+)/Ce(3+)/Dy(3+)/Tb(3+)) doped Ca2Ba3(PO4)3Cl phosphors with the apatite structure have been prepared via a Pechini-type sol-gel process. X-ray diffraction (XRD) and structure refinement, photoluminescence (PL) spectra, cathodoluminescence (CL) spectra, absolute quantum yield, as well as lifetimes were utilized to characterize samples. Under UV light excitation, the undoped Ca2Ba3(PO4)3Cl sample shows broad band photoluminescence centered near 480 nm after being reduced due to the defect structure. Eu(2+) and Ce(3+) ion doped Ca2Ba3(PO4)3Cl samples also show broad 5d → 4f transitions with cyan and blue colors and higher quantum yields (72% for Ca2Ba3(PO4)3Cl:0.04Eu(2+); 67% for Ca2Ba3(PO4)3Cl:0.016Ce(3+)). For Dy(3+) and Tb(3+) doped Ca2Ba3(PO4)3Cl samples, they give strong line emissions coming from 4f → 4f transitions. Moreover, the Ce(3+) ion can transfer its energy to the Tb(3+) ion in the Ca2Ba3(PO4)3Cl host, and the energy transfer mechanism has been demonstrated to be a resonant type, via a dipole-quadrupole interaction. However, under the low voltage electron beam excitation, Tb(3+) ion doped Ca2Ba3(PO4)3Cl samples present different luminescence properties compared with their PL spectra, which is ascribed to the different excitation mechanism. On the basis of the good PL and CL properties of the Ca2Ba3(PO4)3Cl:A (A = Ce(3+)/Eu(2+)/Tb(3+)/Dy(3+)), Ca2Ba3(PO4)3Cl might be promising for application in solid state lighting and field-emission displays.

  12. NaLa(MoO{sub 4}){sub 2}: RE{sup 3+} (RE{sup 3+} = Eu{sup 3+}, Sm{sup 3+}, Er{sup 3+}/Yb{sup 3+}) microspheres: the synthesis and optical properties

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

    Gao, Zhiyi; Wang, Zhiying; Fu, Linlin

    The strong green upconversion (UC) emission were observed in various Er{sup 3+}, Yb{sup 3+} co-doped NaLa(MoO{sub 4}){sub 2} samples synthesized via a hydrothermal route. The UC intensity depends on the dopant concentration, and the optimal UC emission was obtained in NaLa(MoO{sub 4}){sub 2}: 0.02Er{sup 3+}/0.10 Yb{sup 3+}. - Highlights: • The NaLa(MoO{sub 4}){sub 2} microspheres doped with Eu{sup 3+}, Sm{sup 3+} and Er{sup 3+}/Yb{sup 3+} were synthesized by a hydrothermal method. • The effects of the EDTA in the initial solution crystal phase and morphology were studied. • The down-conversion luminescence properties of NaLa(MoO{sub 4}){sub 2}: RE{sup 3+} (RE{sup 3+}more » = Eu{sup 3+}, Sm{sup 3+}) were investigated. • The UC luminescence properties and mechanism of Er{sup 3+}/Yb{sup 3+} co-doped NaLa(MoO{sub 4}){sub 2} was discussed. - Abstract: NaLa(MoO{sub 4}){sub 2}: RE{sup 3+} (RE{sup 3+} = Eu{sup 3+}, Sm{sup 3+}) microspheres have been synthesized at 180 °C via a facile EDTA-mediated hydrothermal route. X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), photoluminescence (PL) spectra were employed to characterize the samples. It was found that the amount of EDTA in the initial solution was responsible for crystal phase and shape determination. The effect of Eu{sup 3+} and Sm{sup 3+} doping concentrations on the luminescent intensity was also investigated in details. Furthermore, the up-conversion (UC) emissions have been observed in a series of Er{sup 3+}/Yb{sup 3+} co-doped NaLa(MoO{sub 4}){sub 2} samples. Concentration dependent studies revealed that the optimal composition was realized for a 2% Er{sup 3+} and 10% Yb{sup 3+}-doping concentration.« less

  13. Enhancing the High-Voltage Cycling Performance of LiNi1/3Co1/3Mn1/3O2/Graphite Batteries Using Alkyl 3,3,3-Trifluoropropanoate as an Electrolyte Additive.

    PubMed

    Zheng, Xiangzhen; Huang, Tao; Pan, Ying; Wang, Wenguo; Fang, Guihuang; Ding, Kaining; Wu, Maoxiang

    2017-06-07

    The present study demonstrates that the use of alkyl 3,3,3-trifluoropropanoate, including methyl 3,3,3-trifluoropropanoate (TFPM) and ethyl 3,3,3-trifluoropropanoate (TFPE), as new electrolyte additive can dramatically enhance the high-voltage performance of LiNi 1/3 Co 1/3 Mn 1/3 O 2 /graphite lithium-ion batteries (3.0-4.6 V, vs Li/Li + ). The capacity retention was significantly increased from 45.6% to 75.4% after 100 charge-discharge cycles due to the addition of 0.2 wt % TFPM in the electrolyte, and significantly increased from 45.6% to 76.1% after 100 charge-discharge cycles due to the addition of 0.5 wt % TFPE in the electrolyte, verifying their suitability in this application. Electrochemical impedance spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy were employed to study the effect of TFPM and TFPE on cell performance. The data indicates that the improved cycling activity can be ascribed to the participation of TFPM or TFPE in the formation of a thinner cathode/electrolyte interfacial film, thereby enhancing the cell cycling performance owing to a reduced interfacial resistance at high voltage.

  14. Yellow to orange-reddish glass phosphors: Sm3+, Tb3+ and Sm3+/Tb3+ in zinc tellurite-germanate glasses

    NASA Astrophysics Data System (ADS)

    Alvarez-Ramos, M. E.; Alvarado-Rivera, J.; Zayas, Ma. E.; Caldiño, U.; Hernández-Paredes, J.

    2018-01-01

    An optical spectroscopy analysis of TeO-GeO2-ZnO glass co-activating Sm3+/Tb3+ ions was carried out through Raman, photoluminescence spectra and decay time profiles as a function of Sm3+ concentration. According to the estimated CIE1931 chromaticity coordinates, the color of the emission can be adjusted from the yellow light region (0.4883, 0.4774), towards the reddish light region (0.5194,0.4144) by increasing the Sm3+ content from 1, 3, 5% mol, co-doped with 1% mol Tb3+ under co-excitation of Sm3+ and Tb3+ at 378 nm. The color temperatures are in the range of 1379-2804 K. Such photoluminescence is generated by the 4G 5/2 → 4H 5/2, 4H 7/2, 4H9/2 emissions of Sm3+ in addition to the 5D4→7F6,5,4,3 emissions of Tb3+; the single doped Sm3+ glass displayed an intense orange light. Meanwhile, co-doped Sm3+/Tb3+ glasses excited at 378 nm showed a significant reduction in Tb3+ emission, with a simultaneous increment in the reddish-orange emission of Sm3+, due to a non-radiative resonant energy transfer from Tb3+ to Sm3+. Decay time profile analysis of the Tb3+ emission as function of Sm3+ ion content suggests that an electric dipole-dipole interaction into Tb3+-Sm3+ clusters might dominate in the energy transfer process, with an efficiency and probability of 0.22, 0.27, 0.38 and 122.8, 327.6, 522.7 s-1, respectively.

  15. 40 CFR 721.3031 - Boric acid (H3BO3), zinc salt (2=3).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Boric acid (H3BO3), zinc salt (2=3... Substances § 721.3031 Boric acid (H3BO3), zinc salt (2=3). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as boric acid (H3BO3), zinc salt (2=3) (PMN P...

  16. 40 CFR 721.3031 - Boric acid (H3BO3), zinc salt (2=3).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Boric acid (H3BO3), zinc salt (2=3... Substances § 721.3031 Boric acid (H3BO3), zinc salt (2=3). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as boric acid (H3BO3), zinc salt (2=3) (PMN P...

  17. Comparative interactomics: analysis of arabidopsis 14-3-3 complexes reveals highly conserved 14-3-3 interactions between humans and plants.

    PubMed

    Paul, Anna-Lisa; Liu, Li; McClung, Scott; Laughner, Beth; Chen, Sixue; Ferl, Robert J

    2009-04-01

    As a first step in the broad characterization of plant 14-3-3 multiprotein complexes in vivo, stringent and specific antibody affinity purification was used to capture 14-3-3s together with their interacting proteins from extracts of Arabidopsis cell suspension cultures. Approximately 120 proteins were identified as potential in vivo 14-3-3 interacting proteins by mass spectrometry of the recovered complexes. Comparison of the proteins in this data set with the 14-3-3 interacting proteins from a similar study in human embryonic kidney cell cultures revealed eight interacting proteins that likely represent reasonably abundant, fundamental 14-3-3 interaction complexes that are highly conserved across all eukaryotes. The Arabidopsis 14-3-3 interaction data set was also compared to a yeast in vivo 14-3-3 interaction data set. Four 14-3-3 interacting proteins are conserved in yeast, humans, and Arabidopsis. Comparisons of the data sets based on biochemical function revealed many additional similarities in the human and Arabidopsis data sets that represent conserved functional interactions, while also leaving many proteins uniquely identified in either Arabidopsis or human cells. In particular, the Arabidopsis interaction data set is enriched for proteins involved in metabolism.

  18. Surface chemistry of PH 3, PF 3 and PCl 3 on Ru(0001)

    NASA Astrophysics Data System (ADS)

    Tao, H.-S.; Diebold, U.; Shinn, N. D.; Madey, T. E.

    1994-06-01

    The adsorption, desorption and decomposition of PH 3, PF 3 and PCl 3 on Ru(0001) have been studied by soft X-ray photoelectron spectroscopy (SXPS) using synchrotron radiation. Due to large chemical shifts in the P 2p core levels, different phosphorus containing surface species can be identified. We find that PF 3 adsorbs molecularly on Ru(0001) at 80 and 300 K. At 80 K, PH 3 saturates the surface with one layer of atomic hydrogen, elemental phosphorus, subhydride (i.e., PHx (0 < x < 3)) and PH 3, with a total phosphorus coverage of 0.4 ML. At 300 K, PH 3 decomposes into atomic hydrogen and elemental phosphorus with a phosphorus coverage of 0.8 ML. At 80 K, PCl 3 adsorbs dissociatively into atomic chlorine, elemental phosphorus, PCl and possibly PCl 2 and PCl 3 in the first monolayer. Formation of multilayers of PCl 3 is observed at 80 K. At 300 K, PCl 3 adsorbs dissociatively as atomic chlorine and elemental phosphorus with a saturation phosphorus coverage of 0.1 ML. The variation in total phosphorus uptake at 300 K from PX3 ( X = H, FandCl) adsorption is a result of competition between site blocking by dissociation fragments and displacement reactions. Annealing surfaces with adsorbed phosphorus to 1000 K results in formation of RuzP ( z = 1 or 2), which is manifested by the chemical shifts in the P2p core level, as well as the P LVV Auger transition. The recombination of adsorbed phosphorus and adsorbed X ( = H, FandCl) from decomposition is also observed, but is a minor reaction channel on the surface. Thermochemical data are used to analyze the different stabilities of PX 3 at 300 K, namely, PF 3 adsorbs molecularly and PH 3 and PCl 3 dissociate completely. First, we compare the heat of molecular adsorption and the heat of dissociative adsorption of PX 3 on Ru(0001), using an enthalpy approach, and find results consistent with experimental observations. Second, we compare the total bond energy difference between molecular adsorption and complete dissociation of

  19. Compound-specific carbon, nitrogen, and hydrogen isotopic ratios for amino acids in CM and CR chondrites and their use in evaluating potential formation pathways

    NASA Astrophysics Data System (ADS)

    Elsila, Jamie E.; Charnley, Steven B.; Burton, Aaron S.; Glavin, Daniel P.; Dworkin, Jason P.

    2012-09-01

    Stable hydrogen, carbon, and nitrogen isotopic ratios (δD, δ13C, and δ15N) of organic compounds can reveal information about their origin and formation pathways. Several formation mechanisms and environments have been postulated for the amino acids detected in carbonaceous chondrites. As each proposed mechanism utilizes different precursor molecules, the isotopic signatures of the resulting amino acids may indicate the most likely of these pathways. We have applied gas chromatography with mass spectrometry and combustion isotope ratio mass spectrometry to measure the compound-specific C, N, and H stable isotopic ratios of amino acids from seven CM and CR carbonaceous chondrites: CM1/2 Allan Hills (ALH) 83100, CM2 Murchison, CM2 Lewis Cliff (LEW) 90500, CM2 Lonewolf Nunataks (LON) 94101, CR2 Graves Nunataks (GRA) 95229, CR2 Elephant Moraine (EET) 92042, and CR3 Queen Alexandra Range (QUE) 99177. We compare the isotopic compositions of amino acids in these meteorites with predictions of expected isotopic enrichments from potential formation pathways. We observe trends of decreasing δ13C and increasing δD with increasing carbon number in the α-H, α-NH2 amino acids that correspond to predictions made for formation via Strecker-cyanohydrin synthesis. We also observe light δ13C signatures for β-alanine, which may indicate either formation via Michael addition or via a pathway that forms primarily small, straight-chain, amine-terminal amino acids (n-ω-amino acids). Higher deuterium enrichments are observed in α-methyl amino acids, indicating formation of these amino acids or their precursors in cold interstellar or nebular environments. Finally, individual amino acids are more enriched in deuterium in CR chondrites than in CM chondrites, reflecting different parent-body chemistry.

  20. Vanadium isotope heterogeneity of the early solar system

    NASA Astrophysics Data System (ADS)

    Nielsen, S.; Auro, M. E. E.; Magna, T.; Davis, D. M.; Mezger, K.; Sarafian, A. R.

    2017-12-01

    Vanadium (V) has two isotopes with masses 50 and 51 that have 51V/50V ratio of 410. This ratio can be modified by production of 50V through cosmic irradiation, heterogeneous distribution of anomalous nucleosynthetic material and stable isotope fractionation. Due to the existence of only two V isotopes in nature, these latter processes cannot directly be distinguished from irradiation processes. Previous data has suggested that Earth is characterized by 51V/50V that is significantly different to that of meteorites. These data are difficult to reconcile with a singular process that caused the V isotope variation in the early Solar System. Here we present new V isotope data for a large range of meteorites in order to investigate the ultimate origin of V isotope variation in the early Solar System. We find limited and non-systematic 51V/50V variation of 0.3‰ for 25 martian meteorites (depleted/intermediate/enriched shergottites, nakhlites, and chassignite and orthopyroxenite ALH 84001), which suggests that igneous processes on Mars did not induce significant V isotope shifts. Our best estimate for V isotope composition of the bulk silicate Mars can thus be approximated by the mean value of the entire Martian meteorite suite. This value is significantly lighter ( 0.4‰) than that measured for pristine terrestrial rocks. In contrast, meteorites from the HED parent body reveal significant 51V/50V variation that may be linked to magmatic processes such as fractional crystallization of Vestan magma ocean. The two data sets illustrate that several processes are likely to explain the V isotope variation found in meteorites. We will also present new V isotope data for carbonaceous and ordinary chondrites and put them in the context of the values found for Earth, Mars and the HED parent body.