Science.gov

Sample records for 4sosub 4center dot2hsub

  1. Studies on the local structures and spin Hamiltonian parameters for the rhombic Nb4+ centers in MO2 (M = Sn, Ti and Ge) crystals

    NASA Astrophysics Data System (ADS)

    Zhang, Z.-H.; Wu, S.-Y.; Xu, P.; Li, L.-L.; Zhang, S.-X.

    2011-02-01

    The local structures and the spin Hamiltonian parameters for the substitutional Nb4+ centers in MO2 (M = Sn, Ti and Ge) crystals are theoretically studied using the perturbation formulas of these parameters for a 4d1 ion in a rhombically compressed octahedron. The above Nb4+ centers are found to experience the Jahn-Teller distortions, characteristic of the relative axial compressions (~ 0.01-0.02 Å) and the non-axial (planar) angular increases (~ 3°). As a result, the ligand octahedra are transformed from original elongation on host tetravalent cation sites to compression in the impurity centers, with additional non-axial distortions smaller than those in the hosts. The influences of the Jahn-Teller distortions and the ligand orbital contributions are also analyzed.

  2. Pseudo-Jahn-Teller and relaxation-rate analyses of a model for the hydride ion at the E' 4 center in alpha quartz

    NASA Astrophysics Data System (ADS)

    Georgiev, M.; Manov, A.

    1988-02-01

    Calculated cluster data on the energy vs hydride-ion displacement for the E' 4 center, as reported by Isoya, Weil, and Halliburton, are re-analyzed in terms of the Pseudo-Jahn-Teller effect. Realistic values are obtained of the vibronic-mixing parameters giving credibility to our interpretation. Relaxation rates are computed of hydrogen transfer between two opposite off-center sites.

  3. Synthesis and characterization of the layered zirconium arsenate Zr{sub 2}O{sub 3}(HAsO{sub 4}){center_dot}nH{sub 2}O

    SciTech Connect

    Bortun, A.I.; Bortun, L.N.; Clearfield, A.; Trobajo, C.; Garcia, J.R.

    1998-04-01

    Layered sodium zirconium arsenate of composition Zr{sub 2}O{sub 3}(NaAsO{sub 4}){center_dot}3H{sub 2}O was prepared by the reaction between Zr(OC{sub 3}H{sub 7}){sub 4} and sodium arsenate in alkaline media (pH > 12) under mild hydrothermal conditions (180--200 C). Two hydrogen forms of the zirconium arsenate ({psi}-ZrAs) Zr{sub 2}O{sub 3}(HAsO{sub 4}){center_dot}3H{sub 2}O and Zr{sub 2}O{sub 3}(HAsO{sub 4}){center_dot}H{sub 2}O, were prepared by acid treatment of the sodium form. The intercalation of n-alkylamines into the {psi}-ZrAs from the gas phase was studied. The synthesized materials were characterized by elemental analysis, thermogravimetric analysis, infrared spectroscopy and powder X-ray diffraction. The data indicate that the zirconium arsenate is isostructural to {psi}-Zr{sub 2}O{sub 3}(HPO{sub 4}){center_dot}nH{sub 2}O (n = 0.5, 1.5). The new compounds exhibit high hydrolytic stability in alkaline media. The ion exchange behavior of the {psi}-Zr{sub 2}O{sub 3}(HAsO{sub 4}){center_dot}3H{sub 2}O towards alkali, alkaline-earth, and some di- and tri-valent metal cations in different solutions was studied over a wide pH range (2--14) by the batch technique.

  4. Investigations of the spin-Hamiltonian parameters and defect structure due to Jahn-Teller effect for the tetragonal Nb4+ center in cubic Cs2ZrCl6 crystal

    NASA Astrophysics Data System (ADS)

    Wu, Xiao-Xuan; Zheng, Wen-Chen

    2015-06-01

    The spin-Hamiltonian parameters (g factors g//, ?, and hyperfine structure constants A//, ?) of the tetragonally compressed Nb4+ center in cubic Cs2ZrCl6 crystal are calculated from two theoretical methods: one is the complete diagonalization (of energy matrix) method and another is the perturbation theory method. Both methods are based on the two-spin-orbit-parameter model where the contributions to spin-Hamiltonian parameters from the spin-orbit parameter of central dn ion (in the conventional crystal field theory) and that of ligand ion via covalence effect are contained. The calculated results from the two methods are in reasonable agreement with the experimental values. The tetragonal distortion of (NbCl6)2- octahedral cluster due to the Jahn-Teller effect for Nb4+ at the cubic Zr4+ site in Cs2ZrCl6 is also acquired. The results are discussed.

  5. Copper uranyl phosphate and arsenate incorporating an organic ligand with a pillared layer structure: [Cu(4,4 Prime -bpy)(UO{sub 2}){sub 0.5}(HPO{sub 4})(H{sub 2}PO{sub 4})]{center_dot}H{sub 2}O and [Cu(4,4 Prime -bpy)(UO{sub 2}){sub 0.5}(HAsO{sub 4})(H{sub 2}AsO{sub 4})]{center_dot}1.5H{sub 2}O

    SciTech Connect

    Wang, Chih-Min; Lii, Kwang-Hwa

    2013-01-15

    Two mixed-metal uranium compounds, [Cu(4,4 Prime -bpy)(UO{sub 2}){sub 0.5}(HPO{sub 4})(H{sub 2}PO{sub 4})]{center_dot}H{sub 2}O (1) and [Cu(4,4 Prime -bpy)(UO{sub 2}){sub 0.5}(HAsO{sub 4})(H{sub 2}AsO{sub 4})]{center_dot}1.5H{sub 2}O (2) have been synthesized under hydrothermal conditions and structurally characterized by single-crystal X-ray diffraction, fluorescence spectroscopy, and magnetic susceptibility. They are the first examples of mixed-metal uranium phosphate and arsenate incorporating an organic ligand. Their structures contain copper uranyl phosphate/arsenate layers which are covalently linked by 4,4 Prime -bpy pillars to form a 3-D framework structure. The fluorescence spectrum of 1 shows the characteristic vibronic structure of the UO{sub 2}{sup 2+} moiety despite the presence of copper(II) ions in its structure. The two compounds are isostructural and crystallize in the monoclinic space group C2/c with a=20.184(4) A, b=8.921(2) A, c=19.095(3) A, {beta}=115.15(1) Degree-Sign , and R{sub 1}=0.0244 for 1, and a=20.184(1) A, b=9.0210(5) A, c=19.714(1) A, {beta}=114.879(1) Degree-Sign , and R{sub 1}=0.0399 for 2. - Graphical abstract.: A new copper uranyl phosphate and the arsenate analog have been presented. The compounds contain copper uranyl phosphate/arsenate layers covalently linked by 4,4 Prime -bipyridine pillars into an open-framework structure.

  6. Probing the electronic structure of [MoOS(4)](-) centers using anionic photoelectron spectroscopy.

    PubMed

    Wang, Xue-Bin; Inscore, Frank E; Yang, Xin; Cooney, J Jon A; Enemark, John H; Wang, Lai-Sheng

    2002-08-28

    Using photodetachment photoelectron spectroscopy (PES) in the gas phase, we investigated the electronic structure and chemical bonding of six anionic [Mo(V)O](3+) complexes, [MoOX(4)](-) (where X = Cl (1), SPh (2), and SPh-p-Cl (3)), [MoO(edt)(2)](-) (4), [MoO(bdt)(2)](-) (5), and [MoO(bdtCl(2))(2)](-) (6) (where edt = ethane-1,2-dithiolate, bdt = benzene-1,2-dithiolate, and bdtCl(2) = 3,6-dichlorobenzene-1,2-dithiolate). The gas-phase PES data revealed a wealth of new electronic structure information about the [Mo(V)O](3+) complexes. The energy separations between the highest occupied molecular orbital (HOMO) and HOMO-1 were observed to be dependent on the O-Mo-S-C(alpha) dihedral angles and ligand types, being relatively large for the monodentate ligands, 1.32 eV for Cl and 0.78 eV for SPh and SPhCl, compared to those of the bidentate dithiolate complexes, 0.47 eV for edt and 0.44 eV for bdt and bdtCl(2). The threshold PES feature in all six species is shown to have the same origin and is due to detaching the single unpaired electron in the HOMO, mainly of Mo 4d character. This result is consistent with previous theoretical calculations and is verified by comparison with the PES spectra of two d(0) complexes, [VO(bdt)(2)](-) and [VO(bdtCl(2))(2)](-). The observed PES features are interpreted on the basis of theoretical calculations and previous spectroscopic studies in the condensed phase.

  7. Crystal field energy levels, spin-Hamiltonian parameters and local structures for the Cr3+ and Mn4+ centers in La3Ga5SiO14 crystals

    NASA Astrophysics Data System (ADS)

    Mei, Yang; Chen, Bo-Wei; Zheng, Wen-Chen; Li, Bang-Xing

    2017-02-01

    The crystal field energy levels (obtained from optical spectra) together with the spin-Hamiltonian parameters g//, g⊥ and D (obtained from EPR spectra) for 3d3 ions Cr3+ and Mn4+ at the trigonal octahedral Ga3+ sites in La3Ga5SiO14 crystals are computed from the complete diagonalization (of energy matrix) method based on the two-spin-orbit-parameter model. The model takes into account the contributions due to the spin-orbit parameter of central dn ion (in the traditional crystal field theory) and that of ligand ions via covalence effect. The calculated results are in rational accord with the experimental values. The calculations also imply that the covalence of (MnO6)8- center in La3Ga5SiO14 crystals is stronger than that of (CrO6)9- center, and the impurity-induced local lattice relaxation for (MnO6)8- center is larger than that for (CrO6)9- cluster because of the larger size and charge mismatch for Mn4+ replacing Ga3+ in La3Ga5SiO14 crystals.

  8. Temperature sensitivity (Q10), and dynamics of soil organic matter (SOM) decomposition in permafrost soils with different carbon quality and under experimental warming. R. Bracho1, E.A.G Schuur1, E. Pegoraro1, K.G. Crummer1, S. Natali2, J. Zhou, Y Luo3, J. L. Wu3, M. Tiedje4, K. Konstantinidis5 1Department of Biology, University of Florida, Gainesville, FL. 2Woods Hole Research Center, Falmouth, MA. 3Institute for Environmental Genomics and Department of Botany and Microbiology, University of Oklahoma, Norman, OK, 4Center for Microbial Ecology, Michigan State University, East Lansing, MI; 5Center for Bioinformatics and Computational Genomics and School of Biology, Georgia Institute of Technology, Atlanta, GA

    NASA Astrophysics Data System (ADS)

    Bracho, R. G.; Schuur, E. A.; Pegoraro, E.; Crummer, K. G.; Natali, S.; Zhou, J.; Wu, L.; Luo, Y.; Tiedje, J. M.; Konstantinidis, K.

    2013-12-01

    Permafrost soils contain approximately1700 Pg of carbon (C), twice the amount of C in the atmosphere. Temperatures in higher latitudes are increasing, inducing permafrost thaw and subsequent microbial decomposition of previously frozen C. This process is one of the most likely positive feedbacks to climate change. Understanding the temperature sensitivity (Q10) and dynamics of SOM decomposition under warming is essential to predict the future state of the earth - climate system. Alaskan tundra soils were exposed to two winter warming (WW) seasons in the field, which warmed the soils by 4°C to 40 cm depth. Soils were obtained from three depths (0 - 15, 15 - 25 and 45 - 55 cm) and differed in initial amounts of labile and recalcitrant C. Soils were incubated in the lab under aerobic conditions, at 15 and 25°C over 365 days. Q10 was estimated at 14, 100 & 280 days of incubation (DOI); C fluxes were measured periodically and dynamics of SOM decomposition (C pool sizes and decay rates) were estimated by fitting a two pool C model to cumulative respired C (Ccum, mgC/ginitialC). After two WW seasons, initial C content tended to decrease through the soil profile and C:N ratio was significantly decreased in the top 15 cm. After one year of incubation, Ccum was twice as high at 25°C as at 15°C and significantly decreased with depth. No significant WW field treatment was detected, although Ccum tended to be lower in warmed soils. Labile C accounted for up to 5% of initial soil C content in the top 15 cm and decreased with depth. Soils exposed to WW had smaller labile C pools, and higher labile C decay rates in the top 25 cm. Q10 significantly decreased with time and depth as labile pool decreased, especially for WW. This decrease with time indicates a lower temperature sensitivity of the most recalcitrant C pool. The deepest WW soil layer, where warming was more pronounced, had significantly lower Q10 compared to control soils at the same depth. After two seasons, the warming treatment affected decomposition by reducing labile C pools and increasing its decay rates. Warming also reduced temperature sensitivity, showing acclimation of the most recalcitrant C pool in the tundra ecosystem.

  9. Muscular Dystrophy

    MedlinePlus

    ... in Duchenne muscular dystrophy. Dev. Med. Child Neurol. Mar 1995;37(3):260-269. 4. Centers for ... DM1) . The International Myotonic Dystrophy Consortium (IDMC). Neurology. Mar 28 2000;54(6):1218-1221. 5. Harper ...

  10. CaSeO4-0.625H2O - Water Channel Occupation in a bassanite Related Structure

    SciTech Connect

    S Fritz; H Schmidt; I Paschke; O Magdysyuk; R Dinnebier; D Freyer; W Voigt

    2011-12-31

    Calcium selenate subhydrate, CaSeO{sub 4} {center_dot} 0.625H{sub 2}O, was prepared by hydrothermal conversion of CaSeO{sub 4} {center_dot} 2H{sub 2}O at 463 K. From the single crystals obtained in the shape of hexagonal needles, 50-300 {micro}m in length, the crystal structure could be solved in a trigonal unit cell with space group P3{sub 2}21. The cell was confirmed and refined by high-resolution synchrotron powder diffraction. The subhydrate was characterized by thermal analysis and Raman spectroscopy.

  11. Photocopy of photograph (original photograph in possession of Atlanta Housing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original photograph in possession of Atlanta Housing Authority, Atlanta, GA). Photographer unknown, June, 1940. VIEW OF STORE AND ADMINISTRATION BUILDING (RIGHT), BUILDING 4 (CENTER) AND BUILDING 5 RIGHT, FROM NORTH FACING SOUTH ALONG TECHWOOD DRIVE. - Techwood Homes (Public Housing), Bounded by North Avenue, Parker Street, William Street & Lovejoy Street, Atlanta, Fulton County, GA

  12. Infants' Early Visual Attention and Social Engagement as Developmental Precursors to Joint Attention

    ERIC Educational Resources Information Center

    Salley, Brenda; Sheinkopf, Stephen J.; Neal-Beevers, A. Rebecca; Tenenbaum, Elena J.; Miller-Loncar, Cynthia L.; Tronick, Ed; Lagasse, Linda L.; Shankaran, Seetha; Bada, Henrietta; Bauer, Charles; Whitaker, Toni; Hammond, Jane; Lester, Barry M.

    2016-01-01

    This study examined infants' early visual attention (at 1 month of age) and social engagement (4 months) as predictors of their later joint attention (12 and 18 months). The sample (n = 325), drawn from the Maternal Lifestyle Study, a longitudinal multicenter project conducted at 4 centers of the National Institute of Child Health and Human…

  13. Handbook for Researching Missing-In-Action Cases: 1941-1960

    DTIC Science & Technology

    1994-02-01

    Legislative Archives (NSC) ........................ 1-9 a. Archival Programs Branch ( NSCA ) ................................................ 1-9 4. Center for...Center for Legislative Archives (NSC) a. Archival Programs Branch ( NSCA ) 1. RG 287-Publications of the U.S. Government Record Group 287 - Publications of

  14. Quasi-Experimental Study: Head Start Preschoolers' Cognitive Development as Assessed by the Learning Accomplishment Profile--Diagnostic

    ERIC Educational Resources Information Center

    Hines, Jeanne M.

    2014-01-01

    Abstract Preschoolers' cognitive abilities were assessed each year as part of the Head Start Program requirements. The Head Start PK-4 Center evaluated preschoolers' cognition by administering the Learning Accomplishment Profile-Diagnostic (LAP-D), as a pretest and posttest measure. The LAP-D study used archival data collected from the 2009-2010…

  15. Implementing automated surveillance for tracking Clostridium difficile infection at multiple healthcare facilities.

    PubMed

    Dubberke, Erik R; Nyazee, Humaa A; Yokoe, Deborah S; Mayer, Jeanmarie; Stevenson, Kurt B; Mangino, Julie E; Khan, Yosef M; Fraser, Victoria J

    2012-03-01

    Automated surveillance using electronically available data has been found to be accurate and save time. An automated Clostridium difficile infection (CDI) surveillance algorithm was validated at 4 Centers for Disease Control and Prevention Epicenter hospitals. Electronic surveillance was highly sensitive, specific, and showed good to excellent agreement for hospital-onset; community-onset, study facility-associated; indeterminate; and recurrent CDI.

  16. Off-Season Enrollment Building.

    ERIC Educational Resources Information Center

    Wassom, Julie

    2002-01-01

    Maintains that the winter months are an ideal time to review and refine a child care center's marketing program. Highlights the following target areas for review: (1) marketing plan; (2) action plan; (3) center or company identity package; (4) center brochure; (5) photos; (6) web site; (7) advertisements; (8) publicity; (9) voice mail message;…

  17. Total syntheses of (-)-alpha-kainic acid and (+)-alpha-allokainic acid via stereoselective C-H insertion and efficient 3,4-stereocontrol.

    PubMed

    Jung, Young Chun; Yoon, Cheol Hwan; Turos, Edward; Yoo, Kyung Soo; Jung, Kyung Woon

    2007-12-21

    Reported herein is a novel approach to the total syntheses of (-)-alpha-kainic acid and (+)-alpha-allokainic acid, where the stereochemistries on C(2), C(3), and C(4) of the pyrrolidine core were introduced efficiently and selectively. A regio- and stereoselective C-H insertion reaction was utilized to prepare the gamma-lactam as an intermediate. A Michael-type cyclization of phenylsulfone with a conjugated acetylenic ketone was developed to prepare the tricyclic ketone as a key intermediate for (-)-alpha-kainic acid. Subsequently, a stereoselective dephenylsulfonylation was carried out successfully to secure the cis relationship at C(3) and C(4) centers. An unprecedented acetylation on the phenylsulfone, followed by a stereoselective dephenylsulfonylation, secured the trans relationship at C(3) and C(4) centers in (+)-alpha-allokainic acid.

  18. Dynamics of light-induced NIR-absorption of Nb4 polarons in SBN

    NASA Astrophysics Data System (ADS)

    Gao, Ming; Vikhnin, V.; Kapphan, S.

    The dynamics of light-induced (Kr+-, Ar+-laser) electronic polarons (Nb4+ centers with broad absorption band around 0.8 eV) and light-induced centers of other types were investigated in SrxBa1-xNb2O6: Cr (SBN:Cr) and in SBN: Ce using FTIR absorption measurements at low temperature. A theoretical model involving Cr3+/Cr4+, Ce3+/Ce4+, Nb4+ electronic polarons and trapping X-centers is proposed. The trapping of polarons at Cr4+/Ce4+ centers with subsequent recharging is shown to play an important role in the polaron dynamics. The predictions of the model are in very good agreement with the experimental results.

  19. Mechanical Properties of Carbon Nanotubes / Hydroxyapatite Composites Prepared by Spark Plasma Sintering

    SciTech Connect

    Tanaka, Masa-aki; Onoki, Takamasa; Omori, Mamoru; Hashida, Toshiyuki; Okubo, Akira

    2006-05-05

    In this study, Multi-Walled Carbon Nanotubes (MWCNTs) / Hydroxylapatite (HAp) composites were made to improve mechanical properties by using Spark Plasma Sintering (SPS) method. Slurry 6 mol of CaHPO4{center_dot}2H2O (DCPD), 4 mol calcium hydroxide and MWCNTs were mixed and sintered by using SPS at 5-120 MPa pressure, 1200-1250 deg. C and in vacuum or N2 atmosphere. The fracture toughness of sintered MWCNTs/HAp composites was increased.

  20. Synthesis and crystal structure of tetrakis(2-pyridinecarboxylato) niobium(IV)-2-ethanol, an octacoordinate dodecahedral d{sup 1} M(A-B){sub 4} system

    SciTech Connect

    Ooi, Bee-Lean; Sakane, Genta; Shibahara, Takashi

    1996-12-04

    The authors report the chemical preparation and crystal structure of the complex [Nb(pyc){sub 4}]{center_dot}2C{sub 2}H{sub 5}OH (pyc = 2-pyridinecarboxylate) in order to test Orgel`s postulate. This complex yields empirical evidence of the verity of Orgel`s postulate, where the {pi}-acceptor ligand is predicted to occupy the B sites and {pi}-donors occupy A sites of a dodecahedron.

  1. Thermal preparation effects on the x-ray diffractograms of compounds produced during flue gas desulfurization

    SciTech Connect

    Wertz, D.L.; Burns, K.H.; Keeton, R.W.

    1995-12-31

    The diffractograms of syn-gypsum and of flue gas desulfurization products indicate that CaSO{sub 4} {center_dot} 2H{sub 2}O is converted to other phase(s) when heated to 100{degrees}C. Syn-hannebachite CaSO{sub 3}{center_dot}0.5H{sub 2}O is unaffected by similar thermal treatment. 6 refs., 3 figs.

  2. Near-IR Direct Detection of Water Vapor in Tau Bootis b

    DTIC Science & Technology

    2014-02-24

    The Astrophysical Journal Letters, 783:L29 (6pp), 2014 March 10 doi:10.1088/2041-8205/783/2/L29 C© 2014. The American Astronomical Society. All...Institute of Technology, Pasadena, CA 91125, USA; alock@caltech.edu 2 Harvard-Smithsonian Center for Astrophysics , Institute for Theory and Computation...Cambridge, MA 02138, USA 3 Department of Astronomy & Astrophysics , Pennsylvania State University, University Park, PA 16802, USA 4 Center for Exoplanet

  3. Xyloglucan oligosaccharides promote growth and activate cellulase: Evidence for a role of cellulase in cell expansion. [Pisum sativum L

    SciTech Connect

    McDougall, G.J.; Fry, S.C. )

    1990-07-01

    Oligosaccharides produced by the action of fungal cellulase on xyloglucans promoted the elongation of etiolated pea (Pisum sativum L.) stem segments in a straight-growth bioassay designed for the determination of auxins. The oligosaccharides were most active at about 1 micromolar. We tested the relative growth-promoting activities of four HPLC-purified oligosaccharides which shared a common glucose{sub 4} {center dot} xylose{sub 3} (XG7) core. The substituted oligosaccharides XG8 (glucose{sub 4} {center dot} xylose{sub 3} {center dot} galactose) and XG9n (glucose{sub 4} {center dot} xylose{sub 3} {center dot} galactose{sub 2}) were more effective than XG7 itself and XG9 (glucose{sub 4} {center dot} xylose{sub 3} {center dot} galactose {center dot} fucose). The same oligosaccharides also promoted the degradation, assayed viscometrically, of xyloglucan by an acidic cellulase from bean (Phaseolus vulgaris L.) leaves. The oligosaccharides were highly active at 10{sup {minus}4} molar, causing up to a fourfold increase in activity, but the effect was still detectable at 1 micromolar. Those oligosaccharides (XG8 and XG9n) which best promoted growth, stimulated cellulase activity to the greatest extent. The oligosaccharides did not stimulate the action of the cellulase in an assay based on the conversion of ({sup 3}H)xyloglucan to ethanol-soluble fragments. This suggests that the oligosaccharides enhanced the midchain hydrolysis of xyloglucan molecules (which would rapidly reduce the viscosity of the solution), at the expense of cleavage near the termini (which would yield ethanol-soluble products).

  4. [FeIII(SR)4]1- Complexes can be Synthesized by the Direct Reaction of Thiolates with FeCl3

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It is shown that the previously characterized [FeIII(SR)4]1- (R=Et, i-Pr, Ph) complexes can be synthesized by the direct reaction of 4 equivalents of LiSR with FeCl3 in DMF solution. [FeIII(SR)4]1- complexes are synthetic analogs for the [FeIII(S-Cystein)4] center in rubredoxin proteins....

  5. Center for the Study of Traumatic Stress

    DTIC Science & Technology

    2016-06-15

    will continue to fulfill our mission. In this Annual Report, we share some of the many contributions we are making to enhance psychological health...Forensic Psychology and Forensic Psychi- New Collaborations in 2015 4 | CENTER FOR THE STUDY OF TRAUMATIC STRESS, USU atry Fellowship training...the project. Psychological Stress and Resilience in Mortuary Affairs (MA) Soldiers: Longitudinal Study Since 2005, CSTS has conducted research on

  6. Zinc bioavailability in pork loin

    SciTech Connect

    Hortin, A.E.; Bechtel, P.J. Baker, D.H. )

    1991-03-15

    Pork loins were uniformly trimmed and divided into three groups: raw, roasted and braised. Following cooking, the loins were freeze dried and then ground to a fine granular consistency. Zinc levels of 51, 60 and 63 mg/kg dry matter (DM) were contained in the raw, roasted and braised products, respectively. The chick bioavailability (BV) assay employed a Zn-deficient soy isolate basal diet that was supplemented with 0, 5 or 10 mg Zn/kg from ZnSO{sub 4}{center dot}H{sub 2}O to produce a standard straight-line response in tibia Zn as a function of supplemental Zn intake. Experimental Zn sources were also added to the basal diet to provide 10 mg Zn/kg. Standard curve methodology indicated that Zn BV was unaffected by cooking. Roasted pork lion had a Zn BV of 184% relative to ZnSO{sub 4}{center dot}H{sub 2}O. Addition of 0.40% L-cysteine to the diet containing 10 mg Zn/kg from ZnSO{sub 4}{center dot}H{sub 2}O increased Zn BV to 175%. Results with histidine as a Zn-enhancing factor were variable. It is apparent that pork loin is an excellent source of bioavailable Zn, and SH-containing compounds such as cysteine and glutathione that are present in meat may contribute to enhanced gut absorption of meat-source Zn.

  7. From dihydrated iron(III) phosphate to monohydrated ammonium-iron(II) phosphate: Solvothermal reaction mediated by acetone-urea mixtures

    SciTech Connect

    Alfonso, Belen F.; Pique, Carmen; Blanco, Jesus A.

    2012-12-15

    By reaction between synthetic phosphosiderite FePO{sub 4}{center_dot}2H{sub 2}O, urea (NH{sub 2}){sub 2}CO, and acetone (CH{sub 3}){sub 2}CO, we report a novel solvothermal synthesis of polycrystalline NH{sub 4}FePO{sub 4}{center_dot}H{sub 2}O. The preparation of other two individual phases, NH{sub 4}Fe{sub 2}(OH)(PO{sub 4}){sub 2}{center_dot}2H{sub 2}O and NH{sub 4}Fe{sub 2}(PO{sub 4}){sub 2}, is also described. The obtained product is a function of the reaction time and the N/P molar ratio in the reagent mixture, and the existence of structural memory in the dissolution-precipitation processes is discussed. Below 25 K, NH{sub 4}FePO{sub 4}{center_dot}H{sub 2}O behaves magnetically in a complex way, because both ferromagnetic and antiferromagnetic signals are superimposed, suggesting the existence of a canting of iron(II) magnetic moments. - Graphical abstract: Solvothermal synthesis of polycrystalline NH{sub 4}FePO{sub 4}{center_dot}H{sub 2}O is presented. The preparation of other two individual phases, NH{sub 4}Fe{sub 2}(OH)(PO{sub 4}){sub 2}{center_dot}2H{sub 2}O and NH{sub 4}Fe{sub 2}(PO{sub 4}){sub 2} as a function of the N/P molar ratio in the reagent mixture and the reaction time, is also described. Highlights: Black-Right-Pointing-Pointer Solvothermal synthesis of NH{sub 4}FePO{sub 4}{center_dot}H{sub 2}O from an Fe(III) phosphate: reduction process. Black-Right-Pointing-Pointer Formation of two intermediate metastable phases: phase diagram. Black-Right-Pointing-Pointer Thermal decomposition in two steps: mass loss of both water and ammonia. Black-Right-Pointing-Pointer Magnetic behaviour: AF+constant spontaneous magnetization.

  8. Preparation, structure, and luminescence of dinuclear lanthanide complexes of a novel imine-amine phenolate macrocycle

    SciTech Connect

    Matthews, K.D.; Kahwa, I.A. ); Williams, D.J. )

    1994-03-30

    Metal-free condensation of 2,6-diformyl-p-cresol with 3,6-dioxa-1,8-octanediamine followed by reduction with sodium tetrahydroborate and addition of lanthanide(III) nitrate salts, in that order, yield (slowly) crystalline dinuclear complexes of a novel imine-amine phenolate macrocycle 2. The decacoordination geometry of the identical Pr[sup 3+] ions in a C[sub 2v] 4A,6B-extended dodecahedron made up of two bidentate NO[sub 3]-ions, two phenolate and two either oxygens, and one imine and one amine nitrogens. Dinuclear lanthanide complexes of 2 appear to be more stable than those of the totally reduced chelate 2 in alcoholic media. The Tb[sub 2]2(NO[sub 3])[sub 4][center dot]1.2CH[sub 3]-OH and (La[sub 0.97]Tb[sub 0.03])[sub 2]2(NO[sub 3])[sub 4][center dot]1.2CH[sub 3]OH compounds exhibit strong Tb[sup 3+] ([sup 5]D[sub 4] [yields] [sup 7]F[sub J]) emission sensitized by the single state of 2 at both 77 and 295 K. No Tb[sup 3+]-Tb[sup 3+] self-quenching or N-H trapping effects are observed at 77 K (decay rate is 598 s[sup [minus]1]); the coordination cavities of 2 are therefore potentially good hosts for Tb[sup 3+] in luminescent diagnostic agents. At room temperature the complex decay kinetics of Tb[sup 3+] in Tb[sub 2]2(NO[sub 3])[sub 4][center dot]1.2CH[sub 3]OH are similar to those of Tb[sub 2]1(NO[sub 3])[sub 4][center dot]H[sub 2]O. But for the dilute complex, (La[sub 0.97]-Tb[sub 0.03])[sub 2]2(NO[sub 3])[sub 4][center dot]1.35CH[sub 3]OH, unusual thermal equilibration of the ligand triplet and Tb[sup 3+] [sup 5]D[sub 4] states occurs at room temperature; the ligand-to-Tb[sup 3+] energy-transfer rate is [approx]4.36 x 10[sup 4] s[sup [minus]1], while Tb[sup 3+]-to-ligand back-energy-transfer is [approx]7.1 x 10[sup 4] s[sup [minus]1].

  9. Transannular Diels-Alder/1,3-Dipolar Cycloaddition Cascade of 1,3,4-Oxadiazoles: Total Synthesis of a Unique Set of Vinblastine Analogues

    PubMed Central

    Campbell, Erica L.; Skepper, Colin K.; Sankar, Kuppusamy; Duncan, Katharine K.; Boger, Dale L.

    2013-01-01

    A powerful tandem [4+2]/[3+2] cycloaddition cascade of 1,3,4-oxadiazoles initiated by a transannular [4+2] cycloaddition is detailed. An impressive four rings, four carbon-carbon bonds, and six stereocenters are set on each site of the newly formed central six-membered ring in a cascade thermal reaction that proceeds at temperatures as low as 80 °C. The resulting cycloadducts provide the basis for the synthesis of unique analogues of vinblastine containing metabolically benign deep-seated cyclic modifications at the C3/C4 centers of the vindoline-derived subunit of the natural product. PMID:24087969

  10. ATOMIC BEAM STUDIES IN THE RHIC H-JET POLARIMETER.

    SciTech Connect

    MAKDISI,Y.; ZELENSKI,A.; GRAHAM,D.; KOKHANOVSKI,S.; MAHLER,G.; NASS,A.; RITTER,J.; ZUBETS,V.; ET AL.

    2005-01-28

    The results of atomic beam production studies are presented. Improved cooling of the atoms before jet formation in the dissociator cold nozzle apparently reduces the atomic beam velocity spread and improves beam focusing conditions. A carefully designed sextupole separating (and focusing) magnet system takes advantage of the high brightness source. As a result a record beam intensity of a 12.4 {center_dot} 10{sup 16} atoms/s was obtained within 10 mm acceptance at the collision point. The results of the polarization dilution factor measurements (by the hydrogen molecules at the collision point) are also presented.

  11. ENVIRONMENTAL REACTIVITY OF SOLID STATE HYDRIDE MATERIALS

    SciTech Connect

    Gray, J; Donald Anton, D

    2009-04-23

    In searching for high gravimetric and volumetric density hydrogen storage systems, it is inevitable that higher energy density materials will be used. In order to make safe and commercially acceptable condensed phase hydrogen storage systems, it is important to understand quantitatively the risks involved in using and handling these materials and to develop appropriate mitigation strategies to handle potential material exposure events. A crucial aspect of the development of risk identification and mitigation strategies is the development of rigorous environmental reactivity testing standards and procedures. This will allow for the identification of potential risks and implementation of risk mitigation strategies. Modified testing procedures for shipping air and/or water sensitive materials, as codified by the United Nations, have been used to evaluate two potential hydrogen storage materials, 2LiBH{sub 4} {center_dot} MgH{sub 2} and NH{sub 3}BH{sub 3}. The modified U.N. procedures include identification of self-reactive substances, pyrophoric substances, and gas-emitting substances with water contact. The results of these tests for air and water contact sensitivity will be compared to the pure material components where appropriate (e.g. LiBH{sub 4} and MgH{sub 2}). The water contact tests are divided into two scenarios dependent on the hydride to water mole ratio and heat transport characteristics. Air contact tests were run to determine whether a substance will spontaneously react with air in a packed or dispersed form. In the case of the 2LiBH{sub 4} {center_dot} MgH{sub 2} material, the results from the hydride mixture compared to the pure materials results showed the MgH{sub 2} to be the least reactive component and LiBH{sub 4} the more reactive. The combined 2LiBH{sub 4} {center_dot} MgH{sub 2} resulted in a material having environmental reactivity between these two materials. Relative to 2LiBH{sub 4} {center_dot} MgH{sub 2}, the chemical hydride NH{sub 3}BH

  12. Snythesis and characterization of the first main group oxo-centered trinuclear carboxylate

    NASA Technical Reports Server (NTRS)

    Duraj, Stan A.

    1994-01-01

    The synthesis and structural characterization of the first main group oxo-centered, trinuclear carboxylato-bridged species is reported, namely (Ga3(mu(sub 3)-O) (mu-O2CC6H5)6 (4-Mepy)3) GaCl4 center dot 4-Mepy (compound 1), where 4-Mepy is 4-methylpyridine. Compound 1 is a main group example of a well-established class of complexes, referred to as 'basic carboxylates' of the general formula (M3(mu(sub 3)-O)(mu-O2CR)6L3)(+), previously observed only for transition metals.

  13. Observation of Instabilities of Coherent Transverse Ocillations in the Fermilab Booster

    SciTech Connect

    Alexahin, Y.; Eddy, N.; Gianfelice-Wendt, E.; Lebedev, V.; Marsh, W.; Pellico, W.; Triplett, K.; /Fermilab

    2012-05-01

    The Fermilab Booster - built more than 40 years ago - operates well above the design proton beam intensity of 4 {center_dot} 10{sup 12} ppp. Still, the Fermilab neutrino experiments call for even higher intensity exceeding 5.5 {center_dot} 10{sup 12} ppp. A multitude of intensity related effects must be overcome in order to meet this goal including suppression of coherent dipole instabilities of transverse oscillations which manifest themselves as a sudden drop in the beam current. In this report we present the results of observation of these instabilities at different tune, coupling and chromaticity settings and discuss possible cures.

  14. New Regularization Method for EXAFS Analysis

    SciTech Connect

    Reich, Tatiana Ye.; Reich, Tobias; Korshunov, Maxim E.; Antonova, Tatiana V.; Ageev, Alexander L.; Moll, Henry

    2007-02-02

    As an alternative to the analysis of EXAFS spectra by conventional shell fitting, the Tikhonov regularization method has been proposed. An improved algorithm that utilizes a priori information about the sample has been developed and applied to the analysis of U L3-edge spectra of soddyite, (UO2)2SiO4{center_dot}2H2O, and of U(VI) sorbed onto kaolinite. The partial radial distribution functions g1(UU), g2(USi), and g3(UO) of soddyite agree with crystallographic values and previous EXAFS results.

  15. Reserve Manpower, Personnel, and Training Research.

    DTIC Science & Technology

    1986-09-01

    ucM) q 24 WWESWEEPMR (MCJ/M"𔃾 28 MOBLE NHORE UNDERSEA WAAR LHTS 4 ADPICIIA 94PS (LST/LSf) 22 CRAFT OF OPPORTIJT UNITS (COOP) 4 SALVAE SUPS (ARS) 4...Centers with the aid of computer technology . Once decentralized, personnel data would .- be captured, maintained, and reported at the local level. In... Technology Mr. Eugene R. Hall 202/696-4844 Novel Training Systems Center 305/646-4498 ,- CDR George Connor, USU Office of the CNO, Op-091 Dr. Stanley A

  16. Isopiestic Determination of the Osmotic and Activity Coefficients of Li2SO4(aq) at T = 298.15 and 323.15 K, and Representation with an Extended Ion-interaction (Pitzer) model

    SciTech Connect

    Rard, J A; Clegg, S L; Palmer, D A

    2007-01-03

    Isopiestic vapor-pressure measurements were made for Li{sub 2}SO{sub 4}(aq) from 0.1069 to 2.8190 mol {center_dot} kg{sup -1} at 298.15 K, and from 0.1148 to 2.7969 mol {center_dot} kg{sup -1} at 323.15 K, with NaCl(aq) as the reference standard. Published thermodynamic data for this system were reviewed, recalculated for consistency, and critically assessed. The present results and the more reliable published results were used to evaluate the parameters of an extended version of Pitzer's ion-interaction model with an ionic-strength dependent third virial coefficient, as well as those of the standard Pitzer model, for the osmotic and activity coefficients at both temperatures. Published enthalpies of dilution at 298.15 K were also analyzed to yield the parameters of the ion-interaction models for the relative apparent molar enthalpies of dilution. The resulting models at 298.15 K are valid to the saturated solution molality of the thermodynamically stable phase Li{sub 2}SO{sub 4} {center_dot} H{sub 2}O(cr). Solubilities of Li{sub 2}SO{sub 4} {center_dot} H{sub 2}O(cr) at 298.15 K were assessed, and the selected value of m(sat.) = 3.13 {+-} 0.04 mol {center_dot} kg{sup -1} was used to evaluate the thermodynamic solubility product K{sub s}(Li{sub 2}SO{sub 4} {center_dot} H{sub 2}O, cr, 298.15 K) = (2.62 {+-} 0.19) and a CODATA-compatible standard molar Gibbs energy of formation {Delta}{sub f}G{sub m}{sup o} (Li{sub 2}SO{sub 4} {center_dot} H{sub 2}O, cr, 298.15 K) = -(1564.6 {+-} 0.5) kJ {center_dot} mol{sup -1}.

  17. Magnesia-ammonium phosphate-bonded cordierite refractory castables: Phase evolution on heating and mechanical properties

    SciTech Connect

    Hipedinger, Nora E.; Scian, Alberto N.; Aglietti, Esteban F

    2004-01-01

    A cordierite refractory castable was developed using the MgO-NH{sub 4}H{sub 2}PO{sub 4} reaction. This castable was made with cordierite-mullite aggregates from scrap refractory material and a cement paste based on magnesia, calcined alumina, silica fume, and ammonium dihydrogen phosphate, which forms cordierite (2MgO{center_dot}2Al{sub 2}O{sub 3}{center_dot}5SiO{sub 2}) during heating at high temperature. The mix with water was cast into steel molds; the cold setting occurs within 30 min. The set castables were thermally treated and the evolution of the phases was observed. Struvite (NH{sub 4}{center_dot}MgPO{sub 4}{center_dot}6H{sub 2}O) was identified at room temperature; between 110 and 750 deg. C, the present phosphates were amorphous to X-ray diffraction (XRD). At 1100 deg. C, magnesium orthophosphate (Mg{sub 3}(PO{sub 4}){sub 2}) and aluminum orthophosphate (AlPO{sub 4}) were present. At 1350 deg. C, the main crystalline phases were cordierite and mullite. Cold and hot flexural strength, thermal shock resistance, and physical properties were measured. The properties of magnesia-phosphate-bonded cordierite castables were compared with cordierite material obtained by conventional slip-casting method from aggregates, clay, talc, and calcined alumina.

  18. A single iron site confined in a graphene matrix for the catalytic oxidation of benzene at room temperature

    PubMed Central

    Deng, Dehui; Chen, Xiaoqi; Yu, Liang; Wu, Xing; Liu, Qingfei; Liu, Yun; Yang, Huaixin; Tian, Huanfang; Hu, Yongfeng; Du, Peipei; Si, Rui; Wang, Junhu; Cui, Xiaoju; Li, Haobo; Xiao, Jianping; Xu, Tao; Deng, Jiao; Yang, Fan; Duchesne, Paul N.; Zhang, Peng; Zhou, Jigang; Sun, Litao; Li, Jianqi; Pan, Xiulian; Bao, Xinhe

    2015-01-01

    Coordinatively unsaturated (CUS) iron sites are highly active in catalytic oxidation reactions; however, maintaining the CUS structure of iron during heterogeneous catalytic reactions is a great challenge. Here, we report a strategy to stabilize single-atom CUS iron sites by embedding highly dispersed FeN4 centers in the graphene matrix. The atomic structure of FeN4 centers in graphene was revealed for the first time by combining high-resolution transmission electron microscopy/high-angle annular dark-field scanning transmission electron microscopy with low-temperature scanning tunneling microscopy. These confined single-atom iron sites exhibit high performance in the direct catalytic oxidation of benzene to phenol at room temperature, with a conversion of 23.4% and a yield of 18.7%, and can even proceed efficiently at 0°C with a phenol yield of 8.3% after 24 hours. Both experimental measurements and density functional theory calculations indicate that the formation of the Fe═O intermediate structure is a key step to promoting the conversion of benzene to phenol. These findings could pave the way toward highly efficient nonprecious catalysts for low-temperature oxidation reactions in heterogeneous catalysis and electrocatalysis. PMID:26665170

  19. Gallium hole traps in irradiated KTiOPO{sub 4}:Ga crystals

    SciTech Connect

    Grachev, V.; Meyer, M.; Malovichko, G.; Hunt, A. W.

    2014-12-07

    Nominally pure and gallium doped single crystals of potassium titanyl phosphate (KTiOPO{sub 4}) have been studied by Electron Paramagnetic Resonance at low temperatures before and after irradiation. Irradiation with 20 MeV electrons performed at room temperature and liquid nitrogen temperature caused an appearance of electrons and holes. Gallium impurities act as hole traps in KTiOPO{sub 4} creating Ga{sup 4+} centers. Two different Ga{sup 4+} centers were observed, Ga1 and Ga2. The Ga1 centers are dominant in Ga-doped samples. For the Ga1 center, a superhyperfine structure with one nucleus with nuclear spin ½ was registered and attributed to the interaction of gallium electrons with a phosphorus nucleus or proton in its surrounding. In both Ga1 and Ga2 centers, Ga{sup 4+} ions substitute for Ti{sup 4+} ions, but with a preference to one of two electrically distinct crystallographic positions (site selective substitution). The Ga doping eliminates one of the shortcomings of KTP crystals—ionic conductivity of bulk crystals. However, this does not improve significantly the resistance of the crystals to electron and γ-radiation.

  20. Isolation and characterization of an Fe,-S8 ferredoxin (ferredoxin II) from Clostridium thermoaceticum.

    PubMed Central

    Elliott, J I; Ljungdahl, L G

    1982-01-01

    A second ferredoxin protein was isolated from the thermophilic anaerobic bacterium Clostridium thermoaceticum and termed ferredoxin II. This ferredoxin was found to contain 7.9 +/- 0.3 iron atoms and 7.4 +/- 0.4 acid-labile sulfur atoms per mol of protein. Extrusion studies of the iron-sulfur centers showed the presence of two [Fe4-S4] centers per mol of protein and accounted for all of the iron present. The absorption spectrum was characterized by maxima at 390 nm (epsilon 390 = 30,400 M-1cm-1) and 280 nm (epsilon 280 = 41.400 M-1 cm-1) and by a shoulder at 300 nm. The ration of the absorbance of the pure protein at 390 nm to the absorbance at 280 nm was 0.74. Electron paramagnetic resonance data showed a weak signal in the oxidized state, and the reduced ferredoxin exhibited a spectrum typical of [Fe4-S4] clusters. Double integration of the reduced spectra showed that two electrons were necessary for the complete reduction of ferredoxin II. Amino histidine, and 1 arginine, and a molecular weight of 6,748 for the native protein. The ferredoxin is stable under anaerobic conditions for 60 min at 70 degrees C. The average oxidation-reduction potential for the two [Fe4-S4] centers was measured as -365 mV. PMID:6282807

  1. Conversion of tribasic lead sulfate to lead dioxide in lead/acid battery plates. 1: Relationship between the phase compositions of plates in the cured and formed states

    NASA Astrophysics Data System (ADS)

    Zerroual, L.; Chelali, N.; Tedjar, F.; Guitton, J.

    1994-10-01

    The influence of the initial amount of H2SO4 added to lead powder on the phase compositions of plates in the cured and formed states has been studied. IR spectra, x-ray diffraction, scanning electron microscope observations, and wet-chemical analysis are used as techniques of investigation. It was found that the phase composition of the paste depends on the H2SO4:oxidized lead powder ratio. In addition, it is found that alpha- and beta-PbO2 are formed in the lead/acid battery positive plate from 3PbO center-dot PbSO4 center-dot H2O. The amounts of these two compounds were strongly affected when varying the quantity of H2SO4 with respect to the lead powder.

  2. Performance and discharge characteristics of doped (beta) MnO2 in H2SO4 electrolyte

    NASA Astrophysics Data System (ADS)

    Desai, Buqui D.; Lobo, Fernando S.; Kamatdalal, V. N.

    1994-10-01

    Doped manganese dioxides (beta-MnO2) were prepared by thermal decomposition (180 C) of manganese nitrate in the presence of weighed quantities of NH4VO3, Na2WO4 center-dot 2H2O, LiNO3, AgNO3, or MoO3. Detailed chemical analyses, surface area, and pycnometric density determinations were carried out, and the electrochemical performance was evaluated in H2SO4 (8 N) electrolyte. The discharge behavior was monitored using constant currents and constant resistances (both continuous and intermittent discharge). Some of the Mo-doped samples together with the Li- and Ag-doped materials performed well as cathodes in H2SO4. The consistency of discharge duration under different discharge regimes was a marked feature of the behavior of some of the compositions.

  3. Enhancement of biodiesel synthesis from soybean oil by potassium fluoride modification of a calcium magnesium oxides catalyst.

    PubMed

    Fan, Mingming; Zhang, Pingbo; Ma, Qinke

    2012-01-01

    Transesterification of soybean oil with methanol was carried out in the presence of CaO-MgO and KF-modified CaO-MgO catalysts at atmospheric pressure. While the methyl ester yield for the CaO-MgO catalyst with a ratio of 8:2 (CaO:MgO) was 63.6%, it was 97.9% for the KF-modified catalyst at a 2% catalyst to the reactants (methanol/oil mixture) weight ratio, a temperature of 65 °C, a methanol-soybean oil ratio of 9:1 and a reaction time of 2.5 h. The KF/CaO-MgO catalyst still yielded 86.7% after four successive uses. The catalytic performance of the KF/CaO-MgO catalyst was attributed to the formation of active KCaF(3) and K(2)MgF(4) centers.

  4. Immobilization and fixation of molybdenum (6) by Portland cement

    SciTech Connect

    Kindness, A.; Lachowski, E.E.; Minocha, A.K.; Glasser, F.P. . Dept. of Chemistry)

    1994-01-01

    The immobilization of molybdenum (6) in Portland cement has been studied. Analytical methods are reviewed. As a precursor to studies using commercial cements, the cement constituent phases Ca[sub 3]Al[sub 2]O[sub 6] and Ca[sub 3]SiO[sub 5] and mixtures of Ca[sub 3]Al[sub 2]O[sub 6] and gypsum (CaSO[sub 4][center dot]2H[sub 2]O) have been synthesized and subsequently hydrated with an aqueous solution containing initially 2,000 ppm Mo. The aqueous Mo contents decrease slowly over the first 12 days before attaining a steady-state concentration, ca. 40--50 ppm. Its main speciation is as molybdate, MoO[sub 4][sup 2[minus

  5. A new zinc pyromellitate, [(C 4N 2H 12) 0.5(NH 2(CH 3) 2][Zn(C 10H 2O 8)]·1.78H 2O, with a layered structure

    NASA Astrophysics Data System (ADS)

    Ganesan, S. V.; Lightfoot, Philip; Natarajan, Srinivasan

    2004-07-01

    A hydrothermal reaction of ZnO, HCl, pyromellitic acid, piperazine and water/DMF mixture gave rise to a layered Zn coordination polymer. The structure, determined by single crystal XRD, consists of a network of ZnO 4 centers, tetrahedrally coordinated by pyromellitate anions giving rise to a two-dimensional sheet structure. The connectivity resembles a 4-connected network in which each Zn atom is connected to four BTEC anions and each BTEC anion is linked to four Zn 2+ ions. The DMF, under hydrothermal conditions, has transformed into dimethylamine. Both the acid and polymer shows photoluminescence with the main emission band for the polymer at about 390 nm ( λex=338 nm). Our continuing investigations clearly reveal that it is profitable to explore amine templated metal-organic frameworks.

  6. Fabrication of an infrared bolometer with a high T sub c superconducting thermometer

    SciTech Connect

    Vergjese, S.; Richards, P.L. . Dept. of Physics Lawrence Berkeley Lab., CA ); Char, K.; Sachtjen, S.A. )

    1990-09-01

    A sensitive high {Tc} superconducting bolometer has been fabricated on a 20 {mu}m thick sapphire substrate with a YBCO thin film transition edge thermometer. Optical measurements with a He-Ne laser gave a noise equivalent power of 2.4{center dot}10{sup {minus}11} W/Hz{sup 1/2} at 10 Hz and a responsivity of 17 V/W in good agreement with electrical bolometer measurements. Gold black smoke was then deposited on the back side of the assembled bolometer as an absorber. Spectral measurements on a Fourier transform spectrometer show that the bolometer has useful sensitivity from visible wavelengths to beyond {approximately}100 {mu}m. This performance is clearly superior to that of a commercial room temperature pyroelectric detector. Some improvement appears possible. 10 refs., 5 figs.

  7. New limit on the present temporal variation of the fine structure constant

    SciTech Connect

    Peik, E.; Lipphardt, B.; Schnatz, H.; Schneider, T.; Tamm, Chr.; Karshenboim, S.G.

    2005-05-05

    A comparison of different atomic frequency standards over time can be used to perform a measurement of the present value of the temporal derivative of the fine structure constant {alpha} in a model-independent way without assumptions on constancy or variability of other parameters. We have measured an optical transition frequency at 688 THz in Yb+ with a cesium atomic clock at two times separated by 2.8 years and find that a variation of this frequency can be excluded within a 1{sigma} relative uncertainty of 4.4{center_dot}10-15 yr-1. Combined with recently published values for the constancy of other transition frequencies this measurement provides a limit on the present variability of {alpha} at the level of 2.0{center_dot}10-15 yr-1. Constraints are also derived for the drift rates of other fundamental constants like the electron/proton mass ratio and the proton g-factor.

  8. Modality of choice for renal replacement therapy for children with acute kidney injury: Results of a survey

    PubMed Central

    Vasudevan, A.; Iyengar, A.; Phadke, K.

    2012-01-01

    Information on current practices in India for management of renal replacement therapy (RRT) in acute kidney injury (AKI) is lacking. We mailed a questionnaire to 26 pediatric nephrology centers across India to obtain information on the current choice of dialysis modality for management of AKI in children. Acute intermittent peritoneal dialysis was available at all centers surveyed, whereas intermittent hemodialysis and continuous RRT were available in 86% and 17% centers, respectively. Peritoneal dialysis was the predominant modality (accounting for more than 80% of all dialysis) in 14 of the 22 centers, while 4 centers used hemodialysis more commonly. The most important factors influencing the modality choice were patient size, hemodynamic stability, and duration of AKI. These results provide insight into the choice of modality and factors influencing their selection in the management of pediatric AKI in our country. PMID:22787314

  9. Formation of crystalline titanium(IV) phosphates from titanium(III) solutions

    SciTech Connect

    Bortun, A.; Jaimez, E.; Llavona, R.; Garcia, J.R.; Rodriguez, J.

    1995-04-01

    Crystalline phases of titanium (IV) phosphate have been obtained from titanium(III) chloride in phosphoric acid solutions. The {alpha}-titanium phosphate synthesis is possible at low temperature (60--80 C). {gamma}-Titanium phosphate is obtained by reflux with very concentrated phosphoric acid in 3--5 hours by oxidation with O{sub 2}. The influence in these reactions of several factors (concentration of reagents, molar ratio P:Ti in the reaction mixture, temperature and reaction) was studied. The {alpha}-titanium phosphate formation takes place in several steps through the sequential formation of amorphous titanium(IV) phosphate, {gamma}-titanium phosphate and/or a semicrystalline titanium(IV) hydroxophosphate, Ti(OH){sub 2}(HPO{sub 4}){center_dot}H{sub 2}O.

  10. Characteristics of gypsum crystal growth over calcium-based slurry in desulfurization reactions

    SciTech Connect

    Chu, K.J.; Yoo, K.S.; Kim, K.T.

    1997-02-01

    A wet absorption of sulfur dioxide in a batch-type reactor was carried out, using three calcium compounds, namely, CaCO{sub 3}, CaO, and Ca(OH){sub 2} as absorbents. Based on Fourier Transform Infrared, X-ray diffraction, and scanning electron microscopy analyses, the different absorbents resulted in the different reaction pathways and mechanisms of crystal formation at the early reaction stage. In particular, the CaSO{sub 3} {center_dot} {1/2}H{sub 2}O produced from CaO and Ca(OH){sub 2} showed spherical aggregates consisting of small subparticles, rather than plate or needle-like crystals, of CaSO{sub 4} {center_dot} 2H{sub 2}O from CaCO{sub 3}. This might be due to the different solubility of the absorbents in water.

  11. The antioxidant effect of derivatives pyroglutamic lactam

    NASA Astrophysics Data System (ADS)

    Rohadi, Atisya; Lazim, Azwani Mat; Hasbullah, Siti Aishah

    2013-11-01

    Diphenylpicrylhydrazyl (DPPH) is widely used for quickly accessing the ability of polyphenols to transfer labile H atoms to radicals. The antioxidant activity of all the synthesized compounds was screened by DPPH method. Compound (4) showed 54% antioxidant potential while all other compounds were found to have moderate to have moderate to mild antioxidant activity ranging from 47-52%. Pyroglutamic lactams have been synthesized stereoselectively in racemic form from levulinic acid as bifunctional adduct using convertible isocyanide in one-pot Ugi 4-center-3-component condensation reaction (U-4C-3CR). The product formed provides biologically interesting products in excellent yields in a short reaction time. The structures of the synthesized compounds were elucidated using spectroscopic data and elemental analysis.

  12. An experimental and theoretical study of the resonant Auger spectrum of the ethene molecule

    NASA Astrophysics Data System (ADS)

    Flammini, R.; Satta, M.; O'Keeffe, P.; Coreno, M.; Kivimäki, A.; de Simone, M.; Carbone, M.; Feyer, V.; Prince, K. C.; Avaldi, L.

    2014-07-01

    Resonant Auger spectra of the ethene molecule excited at energies across the C1s \\to \\;{{\\pi }^{*}} energy band are reported. Our measurements address the unexpected variation of the intensity of the A state with respect to the other singly ionized valence states. An approach, based on group theory and calculations using Coulomb 4-center integrals, is proposed to explain the behaviour of the intensity of the ground state and excited states of the ion upon resonant excitation. The new method provides a calculationally inexpensive route to predict relative intensities of different resonant Auger bands in polyatomic molecules, without the need for an exhaustive knowledge of the potential energy surfaces of the electronic states involved.

  13. A biomimetic copper water oxidation catalyst with low overpotential.

    PubMed

    Zhang, Teng; Wang, Cheng; Liu, Shubin; Wang, Jin-Liang; Lin, Wenbin

    2014-01-08

    Simply mixing a Cu(II) salt and 6,6'-dihydroxy-2,2'-bipyridine (H2L) in a basic aqueous solution afforded a highly active water oxidation catalyst (WOC). Cyclic voltammetry of the solution at pH = 12-14 shows irreversible catalytic current with an onset potential of ~0.8 V versus NHE. Catalytic oxygen evolution takes place in controlled potential electrolysis at a relatively low overpotential of 640 mV. Experimental and computational studies suggest that the L ligand participates in electron transfer processes to facilitate the oxidation of the Cu center to lead to an active WOC with low overpotential, akin to the use of the tyrosine radical by Photosystem II to oxidize the CaMn4 center for water oxidation.

  14. The antioxidant effect of derivatives pyroglutamic lactam

    SciTech Connect

    Rohadi, Atisya; Lazim, Azwani Mat; Hasbullah, Siti Aishah

    2013-11-27

    Diphenylpicrylhydrazyl (DPPH) is widely used for quickly accessing the ability of polyphenols to transfer labile H atoms to radicals. The antioxidant activity of all the synthesized compounds was screened by DPPH method. Compound (4) showed 54% antioxidant potential while all other compounds were found to have moderate to have moderate to mild antioxidant activity ranging from 47–52%. Pyroglutamic lactams have been synthesized stereoselectively in racemic form from levulinic acid as bifunctional adduct using convertible isocyanide in one-pot Ugi 4-center-3-component condensation reaction (U-4C-3CR). The product formed provides biologically interesting products in excellent yields in a short reaction time. The structures of the synthesized compounds were elucidated using spectroscopic data and elemental analysis.

  15. The use of LANDSAT-1 imagery in mapping and managing soil and range resources in the Sand Hills region of Nebraska

    NASA Technical Reports Server (NTRS)

    Seevers, P. M. (Principal Investigator); Drew, J. V.

    1976-01-01

    The author has identified the following significant results. Evaluation of ERTS-1 imagery for the Sand Hills region of Nebraska has shown that the data can be used to effectively measure several parameters of inventory needs. (1) Vegetative biomass can be estimated with a high degree of confidence using computer compatable tape data. (2) Soils can be mapped to the subgroup level with high altitude aircraft color infrared photography and to the association level with multitemporal ERTS-1 imagery. (3) Water quality in Sand Hills lakes can be estimated utilizing computer compatable tape data. (4) Center pivot irrigation can be inventoried from satellite data and can be monitored regarding site selection and relative success of establishment from high altitude aircraft color infrared photography. (5) ERTS-1 data is of exceptional value in wide-area inventory of natural resource data in the Sand Hills region of Nebraska.

  16. Chrysolcolla Redefined as Spertiniite

    SciTech Connect

    Farges, Francois; Benzerara, Karim; Brown, Gordon E., Jr.; /Stanford U., Geo. Environ. Sci. /SLAC, SSRL

    2006-12-13

    XAFS and {mu}-XAFS spectra were collected at the Cu K-edge for seven chrysocolla samples (Peru, USA, and Congo). The results suggest that the local structure around Cu is similar to that in Cu(OH){sub 2} (spertiniite). Cu-L{sub 3} STXM imaging and spectroscopy confirm that the chrysocolla samples examined here consist of mesoscopic Cu(II)-rich domains surrounded by Si-rich domains (in agreement with results from infra-red spectroscopy). Hence, we suggest that chrysocolla, which is generally considered to be orthorhombic with composition (Cu,Al){sub 2}H{sub 2}Si{sub 2}O{sub 5}(OH){sub 4} {center_dot} nH{sub 2}O, is in actually a mesoscopic assemblage composed dominantly of spertiniite (Cu(OH){sub 2}), water and amorphous silica (SiO{sub 2}).

  17. Synthetic pathways to vanadyl organophosphonates through aqueous media

    SciTech Connect

    Gendraud, P.; Bigey, L.; Roy, M.E. de; Besse, J.P.

    1997-01-01

    Synthesis of vanadyl(IV) organophosphonates VORPO{sub 3}{center_dot}nH{sub 2}O (with R = CH{sub 3}, C{sub 2}H{sub 5}, C{sub 6}H{sub 5}) has been investigated by reaction of VOSO{sub 4}{center_dot}5H{sub 2}O + RPO{sub 3}H{sub 2} under refluxing conditions in aqueous media. The influence of different parameters is discussed, and compounds are characterized by X-ray powder diffraction, TGA, IR, XANES, and EXAFS. For example, three crystallographic forms of VOC{sub 6}H{sub 5}PO{sub 3}{center_dot}2H{sub 2}O obtained differ from each other in the location of the trans water molecule in the layered structure.

  18. The energy landscape of uranyl-peroxide species.

    PubMed

    Tiferet, Eitan; Gil, Adrià; Bo, Carles; Shvareva, Tatiana Y; Nyman, May; Navrotsky, Alexandra

    2014-03-24

    Nanoscale uranyl peroxide clusters containing UO2(2+) groups bonded through peroxide bridges to form polynuclear molecular species (polyoxometalates) exist both in solution and in the solid state. There is an extensive family of clusters containing 28 uranium atoms (U28 clusters), with an encapsulated anion in the center, for example, [UO2(O2)(3-x)(OH)(x)(4-)], [Nb(O2)4(3-)], or [Ta(O2)4(3-)]. The negative charge of these clusters is balanced by alkali ions, both encapsulated, and located exterior to the cluster. The present study reports measurement of enthalpy of formation for two such U28 compounds, one of which is uranyl centered and the other is peroxotantalate centered. The [(Ta(O2)4]-centered U28 capsule is energetically more stable than the [(UO2)(O2)3]-centered capsule. These data, along with our prior studies on other uranyl-peroxide solids, are used to explore the energy landscape and define thermochemical trends in alkali-uranyl-peroxide systems. It was suggested that the energetic role of charge-balancing alkali ions and their electrostatic interactions with the negatively charged uranyl-peroxide species is the dominant factor in defining energetic stability. These experimental data were supported by DFT calculations, which agree that the [(Ta(O2)4]-centered U28 capsule is more stable than the uranyl-centered capsule. Moreover, the relative stability is controlled by the interactions of the encapsulated alkalis with the encapsulated anion. Thus, the role of alkali-anion interactions was shown to be important at all length scales of uranyl-peroxide species: in both comparing clusters to clusters; and clusters to monomers or extended solids.

  19. Safety and Efficacy of PDpoetin for Management of Anemia in Patients with end Stage Renal Disease on Maintenance Hemodialysis: Results from a Phase IV Clinical Trial.

    PubMed

    Javidan, Abbas Norouzi; Shahbazian, Heshmatollah; Emami, Amirhossein; Yekaninejad, Mir Saeed; Emami-Razavi, Hassan; Farhadkhani, Masoumeh; Ahmadzadeh, Ahmad; Gorjipour, Fazel

    2014-08-26

    Recombinant human erythropoietin (rHuEPO) is available for correcting anemia. PDpoetin, a new brand of rHuEPO, has been certified by Food and Drug Department of Ministry of Health and Medical Education of Iran for clinical use in patients with chronic kidney disease. We conducted this post-marketing survey to further evaluate the safety and efficacy of PDpoetin for management of anemia in patients on maintenance hemodialysis. Patients from 4 centers in Iran were enrolled for this multicenter, open-label, uncontrolled phase IV clinical trial. Changes in blood chemistry, hemoglobin and hematocrit levels, renal function, and other characteristics of the patients were recorded for 4 months; 501 of the patients recruited, completed this study. Mean age of the patients was 50.9 (±16.2) years. 48.7% of patients were female. Mean of the hemoglobin value in all of the 4 centers was 9.29 (±1.43) g/dL at beginning of the study and reached 10.96 (±2.23) g/dL after 4 months and showed significant increase overall (P<0.001). PDpoetin dose was stable at 50-100 U/kg thrice weekly. Hemorheologic disturbancesand changes in blood electrolytes was not observed. No case of immunological reactions to PDpoetin was observed. Our study, therefore, showed that PDpoetin has significantly raised the level of hemoglobin in the hemodialysis patients (about 1.7±0.6 g/dL). Anemia were successfully corrected in 49% of patients under study. Use of this biosimilar was shown to be safe and effective for the maintenance of hemoglobin in patients on maintenance hemodialysis.

  20. Synthesis and characterization of micrometer Cu/PVP architectures

    SciTech Connect

    Luo, Huajuan; Zhao, Yanbao; Sun, Lei

    2011-08-15

    Graphical abstract: A simple method for the synthesis of novel micrometer flower-like Cu/PVP architectures was introduced. Highlights: {yields} Micrometer flower-like copper/polyvinylpyrrolidone architectures were obtained by a simple chemical route. {yields} The amount of N{sub 2}H{sub 4}{center_dot}H{sub 2}O, the reaction temperature, the molar ratio of CuCl{sub 2} to PVP and different molecular weights of PVP play an important role in the controlling the morphology of the Cu/PVP architectures. {yields} A possible mechanism of the formation of Cu/PVP architectures was discussed. -- Abstract: Micrometer-sized flower-like Cu/polyvinylpyrrolidone (PVP) architectures are synthesized by the reduction of copper (II) salt with hydrazine hydrate in aqueous solution in the presence of PVP capping agent. The resulting Cu/PVP architectures are investigated by UV-vis spectroscopy, transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and scanning electron microscopy (SEM). The Cu/PVP flowers have uniform morphologies with an average diameter of 10 {mu}m, made of several intercrossing plates. The formation of Cu/PVP flowers is a new kinetic control process, and the factors such as the amount of N{sub 2}H{sub 4}{center_dot}H{sub 2}O, reaction temperature, molar ratio of CuCl{sub 2} to PVP and molecular weight of PVP have significant effect on the morphology of Cu/PVP architectures. A possible mechanism of the formation of micrometer Cu/PVP architectures was discussed.

  1. Erectile Dysfunction in Individuals with Neurologic Disability: A Hospital-based Cross-sectional Study

    PubMed Central

    Gervasi, Giuseppe; Naro, Antonino; de Luca, Rosaria; Marullo, Michelangelo; Bramanti, Placido

    2016-01-01

    Objective: Neurogenic erectile dysfunction can be broadly defined as an inability to sustain or maintain a penile erection due to neurologic impairment. Sexual problems can occur due to any lesion affecting the central and peripheral nervous system. The aim of this study was to evaluate the prevalence and causes of erectile dysfunction in a group of hospital inpatients suffering from neurologic disorders. Methods: Three-hundred and twenty six male patients admitted to the Neurorehabilitation Unit of IRCCS Centro Neurolesi “Bonino-Pulejo” in Messina Italy from March 2012 to June 2013 were screened for erectile dysfunction using the International Index of Erectile Function questionnaire. The patients who reported erectile dysfuntion underwent vascular, neurophysiological, and hormonal testing, and were divided into two groups according to their lesion sites: G1 (lesions above the S2-S4 center) and G2 (lesions below the S2-S4 center). Results: Of the 326 admitted patients, 126 patients (38.6%), mean age of 54.56±11.74 years (age range 27-82 years), were affected by erectile dysfunction (i.e., scored ≤21). A statistically significant correlation between International Index of Erectile Function questionnaire scores and location of the neurologic lesions was observed in G2 (r=0.22) with an increased risk of erectile dysfuntion of around 2:1 (odds ratio=1.87) without influences related to aging. Conclusion: The occurence of erectile dysfunction is significantly more prevalent among neurologically disabled men, particularly those with lesions below S2-S4, than among men without neurologic disability. Considering the prevalence of erectile dysfunction among neurologically disabled men, sexual functioning should be regularly evaluated during acute and long-term rehabilitation, and any existing sexual dysfunction should be addressed in the treatment plan. PMID:27413582

  2. NICKEL SPECIES EMISSION INVENTORY FOR OIL-FIRED BOILERS

    SciTech Connect

    Kevin C. Galbreath; Richard L. Schulz; Donald L. Toman; Carolyn M. Nyberg

    2004-01-01

    Representative duplicate fly ash samples were obtained from the stacks of 400-MW and 385-MW utility boilers (Unit A and Unit B, respectively) using a modified U.S. Environmental Protection Agency (EPA) Method 17 sampling train assembly as they burned .0.9 and 0.3 wt% S residual oils, respectively, during routine power plant operations. Residual oil fly ash (ROFA) samples were analyzed for nickel (Ni) concentrations and speciation using inductively coupled plasma-atomic emission spectroscopy, x-ray absorption fine structure (XAFS) spectroscopy, x-ray diffraction (XRD), and a water-soluble Ni extraction method. ROFA water extraction residues were also analyzed for Ni speciation using XAFS and XRD. Total Ni concentrations in the ROFAs were similar, ranging from 1.3 to 1.5 wt%; however, stack gas Ni concentrations in the Unit A were {approx}990 {micro}g/Nm{sup 3} compared to {approx}620 {micro}g/Nm{sup 3} for Unit B because of the greater residual oil feed rates employed at Unit A to attain higher load (i.e., MW) conditions with a lower heating value oil. Ni speciation analysis results indicate that ROFAs from Unit A contain about 3 wt% NiSO{sub 4} {center_dot} xH{sub 2}O (where x is assumed to be 6 for calculation purposes) and a Ni-containing spinel compound, similar in composition to (Mg,Ni)(Al,Fe){sub 2}O{sub 4}. ROFAs from Unit B contain on average 2.0 wt% NiSO{sub 4} {center_dot} 6H{sub 2}O and 1.1 wt% NiO. XAFS and XRD analyses did not detect any nickel sulfide compounds, including nickel subsulfide (Ni{sub 3}S{sub 2}) (XAFS detection limit is 5% of the total Ni concentration). In addition, XAFS measurements indicated that inorganic sulfate and organic thiophene species account for >97% of the total sulfur in the ROFAs. The presence of NiSO{sub 4} {center_dot} xH{sub 2}O and nickel oxide compound mixtures and lack of carcinogenic Ni{sub 3}S{sub 2} or nickel sulfide compounds (e.g., NiS, NiS{sub 2}) in ROFAs stack-sampled from 400- and 385-MW boilers are contrary

  3. Inhibited Release of Mobile Contaminants from Hanford Tank Residual Waste

    SciTech Connect

    Cantrell, Kirk J.; Heald, Steve M.; Arey, Bruce W.; Lindberg, Michael J.

    2011-03-03

    Investigations of contaminant release from Hanford Site tank residual waste have indicated that in some cases certain contaminants of interest (Tc and Cr) exhibit inhibited release. The percentage of Tc that dissolved from residual waste from tanks 241-C-103, 241-C-106, 241-C-202, and 241-C-203 ranged from approximately 6% to 10%. The percent leachable Cr from residual waste from tanks C-103, C 202, and C-203 ranged from approximately 1.1% to 44%. Solid phase characterization results indicate that the recalcitrant forms of these contaminants are associated with iron oxides. X-ray absorption near edge structure analysis of Tc and Cr in residual waste indicates that these contaminants occur in Fe oxide particles as their lower, less soluble oxidation states [Tc(IV) and Cr(III)]. The form of these contaminants is likely as oxides or hydroxides incorporated within the structure of the Fe oxide. Leaching behavior of U from tank residual waste was studied using deionized water, and CaCO3 and Ca(OH)2 saturated solutions as leachants. The release behavior of U from tank residual waste is complex. Initial U concentrations in water and CaCO3 leachants are high due to residual amounts of the highly soluble U mineral cejkaite. As leaching and dilution occur NaUO2PO4 {center_dot} xH2O, Na2U2O7(am) and schoepite (or a similar phase) become the solubility controlling phases for U. In the case of the Ca(OH)2 leachant, U release from tank residual waste is dramatically reduced. Thermodynamic modeling indicates that the solubility of CaUO4(c) controls release of U from residual waste in the Ca(OH)2 leachants. It is assumed the solubility controlling phase is actually a hydrated version of CaUO4 with a variable water content ranging from CaUO4 to CaUO4 {center_dot} (H2O). The critically reviewed value for CaUO4(c) (log KSP0 = 15.94) produced good agreement with our experimental data for the Ca(OH)2 leachates.

  4. Synthesis, crystal structures, and luminescent properties of Cd(II) coordination polymers assembled from semi-rigid multi-dentate N-containing ligand

    SciTech Connect

    Yuan, Gang; Shao, Kui-Zhan; Chen, Lei; Liu, Xin-Xin; Su, Zhong-Min; Ma, Jian-Fang

    2012-12-15

    Three new polymers, [Cd(L){sub 2}(H{sub 2}O){sub 2}]{sub n} (1), [Cd{sub 3}(L){sub 2}({mu}{sub 3}-OH){sub 2}({mu}{sub 2}-Cl){sub 2}(H{sub 2}O){sub 2}]{sub n} (2), {l_brace}[Cd{sub 2}(L){sub 2}(nic){sub 2}(H{sub 2}O){sub 2}]{center_dot}H{sub 2}O{r_brace}{sub n} (3) (HL=5-(4-((1H-1,2,4-triazol-1-yl)methyl)phenyl)-1H-tetrazole, Hnic=nicotinic acid) have been prepared and structurally characterized. Compounds 1 and 2 display 2D monomolecular layers built by the inter-linking single helical chains and L{sup -} ligands connecting chain-like [Cd({mu}{sub 3}-OH)({mu}{sub 2}-Cl)]{sub n} secondary building units, respectively. Compound 3 is constructed from the mixed ligands and possesses a (3,4)-connected framework with (4{center_dot}8{sup 2})(4{center_dot}8{sup 2}{center_dot}10{sup 3}) topology. Moreover, the fluorescent properties of HL ligand and compounds 1-3 are also been investigated. - Graphical abstract: Three new coordination polymers based on the semi-rigid multidentate N-donor ligand have been successfully synthesized by hydrothermal reaction. Complexes 1 and 2 exhibit the 2D layers formed by inter-linking single helices and L{sup -} anions bridging 1D chain-like SBUs, respectively. Complex 3 is buit by L{sup -} and assistant nic{sup -} ligands connecting metal centers and possesses a (3,4)-connected framework with (4 Multiplication-Sign 8{sup 2})(4 Multiplication-Sign 8{sup 2} Multiplication-Sign 10{sup 3}) topology. Moreover, these complexes display fluorescent properties indicating that they may have potential applications as optical materials. Highlights: Black-Right-Pointing-Pointer Three Cd-compounds were prepared from semi-rigid HL ligand with different N-containing groups. Black-Right-Pointing-Pointer They exhibit diverse structures from 2D monomolecular layer to 3D covalent framework. Black-Right-Pointing-Pointer The HL ligands displayed various coordination modes under different reaction conditions. Black-Right-Pointing-Pointer These compounds exhibit

  5. Drying results of K-Basin fuel element 3128W (run 2)

    SciTech Connect

    Abrefah, J.; Klinger, G.S.; Oliver, B.M.; Marshman, S.C.; MacFarlan, P.J.; Ritter, G.A.; Flament, T.A.

    1998-07-01

    An N-Reactor outer fuel element that had been stored underwater in the Hanford 100 Area K-East Basin was subjected to a combination of low- and high-temperature vacuum drying treatments. These studies are part of a series of tests being conducted by Pacific Northwest National Laboratory on the drying behavior of N-Reactor spent nuclear fuel elements removed from both the K-West and K-East Basins. The drying test series was designed to test fuel elements that ranged from intact to severely damaged. The fuel element discussed in this report was removed from an open K-East canister (3128W) during the first fuel selection campaign conducted in 1995, and has remained in wet storage in the Postirradiation Testing Laboratory (PTL, 327 Building) since that time. Although it was judged to be breached during in-basin (i.e., K-Basin) examinations, visual inspection of this fuel element in the hot cell indicated that it was likely intact. Some scratches on the coating covering the cladding were identified before the furnace test. The drying test was conducted in the Whole Element Furnace Testing System located in G-Cell within the PTL. This test system is composed of three basic systems: the in-cell furnace equipment, the system gas loop, and the analytical instrument package. Element 3128W was subjected to the drying processes based on those proposed under the Integrated Process Strategy, which included a hot drying step. Results of the Pressure Rise and Gas Evolution Tests suggest that most of the free water in the system was released during the extended CVD cycle (68 hr versus 8 hr for the first run). An additional {approximately}0.34 g of water was released during the subsequent HVD phase, characterized by multiple water release peaks, with a principle peak at {approximately}180 C. This additional water is attributed to decomposition of a uranium hydrate (UO{sub 4}{center_dot}4H{sub 2}O/UO{sub 4}{center_dot}2H{sub 2}O) coating that was observed to be covering the surface

  6. Biological determinants of photobioreactor design. 6th Quarterly report, October 1994--December 1994

    SciTech Connect

    Palsson, B.O.; Brown, G.G.

    1995-03-01

    A novel photobioreactor (PBR) system using light-emitting diodes (LEDs) as a sole light source was constructed and operated with continuous medium perfusion. Direct internal illumination by 680 nm LEDs could deliver as high as 50 mW/cm{sup 2} of light into the culture medium. Gas transfer by internal sparging had the capacity to transfer 250 mmol O{sub 2}/L culture/h. Nutritional limitations could be overcome by continuous perfusion, supplying the medium components to the culture without increasing osmolarity, while removing potentially inhibitory cellular wastes. When the PBR operated in a continuous perfusion mode with a perfusion rate of 6 reactor volumes a day (6 VVD), it could support ultra high-density algal cultures up to cell concentrations of 4{center_dot}10{sup 9} cells/mL and total cell volume fractions of 9.4% v/v (about 25 g dry weight/L). The oxygen production rate at its peak was 13 to 15 mmol/L culture/h. This performance represents the highest reported cell densities attained in photoautotrophic cultures. Continuous perfusion allowed for long-term stable oxygen production, while oxygen production in batch mode ceased when stationary phase was reached. The results presented suggest that PBR technology can still be significantly improved.

  7. Measurement of the Decay B- to D*0 e- anti-nu_e

    SciTech Connect

    Aubert, B.

    2008-01-15

    Using 226 million B{bar B} events recorded on the {Upsilon}(4S) resonance with the BABAR detector at the SLAC e{sup +}e{sup -} PEP-II storage rings, they reconstruct B{sup -} {yields} D*{sup 0}e{sup -}{bar {nu}}{sub e} decays using the decay chain D*{sup 0} {yields} D{sup 0}{pi}{sup 0} and D{sup 0} {yields} K{sup -} {pi}{sup +}. From the dependence of their differential rate on the w, the dot product of the four-velocities of B{sup -} and D*{sup 0}, and using the form factor description by Caprini et al. with the parameters F(1) and {rho}{sub 1{sub 1}}{sup 2}, they obtain the results {rho}{sub A{sub 1}}{sup 2} = 1.16 {+-} 0.06 {+-} 0.08, F(1) {center_dot} |V{sub cb}| = (35.9 {+-} 0.6 {+-} 1.4) {center_dot} 10{sup -3}, and {beta}(B{sup -} {yields} D*{sup 0} e{sup -}{bar {nu}}{sub e}) = (5.56 {+-} 0.08 {+-} 0.41)%.

  8. Increased fluorescence intensity in CaTiO3:Pr3+ phosphor due to NH3 treatment and Nb Co-doping

    NASA Astrophysics Data System (ADS)

    Holliday, K. S.; Kohlgruber, T. A.; Tran, I. C.; Åberg, D.; Seeley, Z. M.; Bagge-Hansen, M.; Srivastava, A. M.; Cherepy, N. J.; Payne, S. A.

    2016-10-01

    Development of next generation red phosphors for commercial lighting requires understanding of how increased luminescence is achieved by various treatment strategies. In this work, we compare co-doping with Nb to NH3 treatment of CaTiO3:Pr phosphors to reveal a general mechanism responsible for the increased luminescence. The phosphors were synthesized using standard solid-state synthesis techniques and the fluorescence was characterized for potential use in fluorescent lighting, with 254 nm excitation. The lifetime of the fluorescence was determined and used to identify a change in a trap state by the co-doping of Nb5+ in the phosphor. The oxidation state of the Pr was probed by NEXAFS and revealed that both Nb5+ co-doping and NH3 treatment reduced the number of non-fluorescing Pr4+ centers. Calculations were performed to determine the energetically favorable defects. Vacuum annealing was also used to further probe the nature of the trap state. It was determined that NH3 treatments reduce the number of Pr4+ non-fluorescing centers, while Nb5+ co-doping additionally reduces the number of excess oxygen trap states that quench the fluorescence.

  9. Financing energy access through community participatory equity: Building and modeling a multidimensional energy access framework for rural community-level PV micro-grids to inform market entry strategy

    NASA Astrophysics Data System (ADS)

    Ananthaneni, Sahithi

    Research on nanomaterials in various fields such as industrial chemicals, biomedical technology, and electronic applications are providing a platform to answer key challenges in terms of energy storage or conversion. In the work described here, we worked on two different projects focusing on both nanoelectronics and nanocatalysis. We present DFT calculations to study the geometric structure and charge transfer to the GaCl4 center in (BETS)2-GaCl4 on the Ag (111) and Ag (100) surfaces, with multiple successive F substitutions onto the Ga center. Results show two interesting important phenomena: first, that the amount of charge transfer is indeed highly surface sensitive (by about .6 net electrons in this case), and second, that substitution of different amounts of F halogenation on the Ga center also has profound effects on the charge transfer to the Ga center. We studied electrochemical conversion of CO2 into a recycled value added chemical fuel such as CH4, or CH3OH via graphene supported WC nanoparticle catalysts. In this work we present the results of DFT calculations to understand the thermodynamic energy landscape of CO2 reduction to CH4 and to CH3OH.

  10. Heavy metals in wastewater: Modelling the hydroxide precipitation of copper(II) from wastewater using lime as the precipitant

    SciTech Connect

    Baltpurvins, K.A.; Burns, R.C.; Lawrance, G.A.

    1996-12-31

    The effect of effluent composition (Cl{sup {minus}}, SO{sub 4}{sup 2{minus}} or CO{sub 3}{sup 2{minus}}) on the efficiency of the hydroxide precipitation of Cu(II) modelling lime (CaO) as the precipitant has been predicted using the solubility domain approach and has been experimentally validated. Solubility domains were based on the phases that were found to be solubility-limiting for systems representing potential effluent chemical composition limits. The generated solubility domains generally encompassed the experimentally observed solubilities, thereby providing effluent treatment quality assurance ranges for the hydroxide precipitation process. The presence of gypsum (CaSO{sub 4{center_dot}}2H{sub 2}O) and calcite (CaCO{sub 3}) as secondary precipitates had little effect on the observed residual Cu(II) solubilities, with Cu(II) mobility being governed by the least-soluble kinetically precipitated (rather than thermodynamically favored) phase in the system under study.

  11. Effects of salts on preparation and use of calcium silicates for flue gas desulfurization

    SciTech Connect

    Kind, K.K.; Wassermann, P.D.; Rochelle, G.T. )

    1994-02-01

    High surface area calcium silicate hydrates that are highly reactive with SO[sub 2] can be made by slurrying fly ash and lime in water at elevated temperatures for several hours. This concept is the basis for the ADVACATE (ADVAnced siliCATE) process for flue gas desulfurization. This paper examines the impact of salts on such a system. Two low calcium fly ashes, from the Shawnee and Clinch River power plants, were examined. The addition of gypsum (CaSO[sub 4][center dot]2H[sub 2]O) or calcium chloride to the slurry system increased the dissolved calcium concentration, allowing the reaction rate to increase and the maximum surface area to more than double in some cases. This increase came despite a lower solution hydroxide level. The salts also enhanced the reaction of the sorbent with sulfur dioxide. This resulted from the higher equilibrium moisture on the sorbent at any humidity due to the deliquescent properties of some of the salts used (calcium chloride and calcium nitrate). Solids made without the deliquescent salts exhibited equilibrium moisture adsorption consistent with a type-II BET isotherm while the deliquescent salts caused hysteresis in the adsorption/desorption isotherm. 22 refs., 10 figs., 2 tabs.

  12. Sub-surface deposits of hydrous silicates or hydrated magnesium sulfates as hydrogen reservoirs near the Martian equator : plausible or not?

    SciTech Connect

    Fialips, C. I.; Carey, J. W.; Vaniman, D. T.; Feldman, W. C.; Bish, D. L.; Mellon, M. T.

    2004-01-01

    Neutron maps obtained using the neutron spectrometer (NS) and the high-energy neutron detector aboard the Mars Odyssey spacecraft reveal variations in the concentration of hydrogen over the martian low to middle latitudes, with up to {approx}10 wt% water-equivalent hydrogen in some equatorial regions. Infrared spectroscopic data provide evidence of chemically and/or physically bound H{sub 2}O and/or OH. Likewise, the decrease in flux of epithermal neutrons in Arabia Terra and southwest of Olympus Mons has been attributed to enhanced concentration of water-bearing minerals in the subsurface. The near-surface martian regolith is expected to contain both unweathered and weathered materials. It may contain significant and heterogeneously distributed amounts of hydrous minerals, such as clays, zeolites, and/or salt hydrates, such as MgSO{sub 4} {center_dot} nH{sub 2}O. Experimental studies suggest that if such water-bearing minerals formed in the past on the martian surface, they may retain significant amounts of water under present martian surface conditions. Hydrous minerals could thus account for some or all of the water observed in the martian regolith by Odyssey. Our study uses surface P-T data to predict regions of stability and the hydration state of selected water-bearing minerals from low to middle latitudes and to identify the nature and amount of hydrous minerals that could possibly account for the water observed by NS.

  13. The Human Microbiome Project strategy for comprehensive sampling of the human microbiome and why it matters.

    PubMed

    Aagaard, Kjersti; Petrosino, Joseph; Keitel, Wendy; Watson, Mark; Katancik, James; Garcia, Nathalia; Patel, Shital; Cutting, Mary; Madden, Tessa; Hamilton, Holli; Harris, Emily; Gevers, Dirk; Simone, Gina; McInnes, Pamela; Versalovic, James

    2013-03-01

    The Human Microbiome Project used rigorous good clinical practice standards to complete comprehensive body site sampling in healthy 18- to 40-yr-old adults, creating an unparalleled reference set of microbiome specimens. To ensure that specimens represented minimally perturbed microbiomes, we first screened potential participants using exclusion criteria based on health history, including the presence of systemic diseases (e.g., hypertension, cancer, or immunodeficiency or autoimmune disorders), use of potential immunomodulators, and recent use of antibiotics or probiotics. Subsequent physical examinations excluded individuals based on body mass index (BMI), cutaneous lesions, and oral health. We screened 554 individuals to enroll 300 (149 men and 151 women, mean age 26 yr, mean BMI 24 kg/m, 20.0% racial minority, and 10.7% Hispanic). We obtained specimens from the oral cavity, nares, skin, gastrointestinal tract, and vagina (15 specimens from men and 18 from women). The study evaluated longitudinal changes in an individual's microbiome by sampling 279 participants twice (mean 212 d after the first sampling; range 30-359 d) and 100 individuals 3 times (mean 72 d after the second sampling; range 30-224 d). This sampling strategy yielded 11,174 primary specimens, from which 12,479 DNA samples were submitted to 4 centers for metagenomic sequencing. Our clinical design and well-defined reference cohort has laid a foundation for microbiome research.

  14. Determination of Nickel Species in Stack Emissions from Eight Residual Oil-Fired Utility Steam-Generating Units

    SciTech Connect

    F Huggins; K Galbreath; K Eylands; L Van Loon; J Olson; E Zillioux; S Ward; P Lynch; P Chu

    2011-12-31

    XAFS spectroscopy has been used to determine the Ni species in particulate matter collected on quartz thimble filters in the stacks of eight residual (No. 6 fuel) oil-burning electric utility steam-generating units. Proper speciation of nickel in emitted particulate matter is necessary to correctly anticipate potential health risks. Analysis of the spectroscopic data using least-squares linear combination methods and a newly developed method specific for small quantities of Ni sulfide compounds in such emissions show that potentially carcinogenic Ni sulfide compounds are absent within the detection limits of the method ({le}3% of the total Ni) in the particulate matter samples investigated. In addition to the major nickel sulfate phase (NiSO{sub 4} {center_dot} 6H{sub 2}O), lesser amounts of (Ni,Mg)O and/or NiFe{sub 2}O{sub 4} were also identified in most emission samples. On the basis of the results from these emission characterization studies, the appropriateness of the U.S. Environmental Protection Agency's assumption that the Ni compound mixture emitted from residual oil-fired power plants is 50% as carcinogenic as nickel subsulfide (Ni{sub 3}S{sub 2}) should be re-evaluated.

  15. Bioremediation enhancement of phenanthrene contaminated soils by chemical pre-oxidation

    SciTech Connect

    Van Kemenade, I.; Anderson, W.A.; Scharer, J.M.; Moo-Young, Murray

    1995-12-31

    A two-step oxidation process was investigated for the treatment of phenanthrene contaminated soil fines (particle diameter {le}63 {mu}m) resulting from a soil washing process. Oxone{reg_sign} (2KHSO{sub 5}{center_dot}KHSO{sub 4}{center_dot}K{sub 2}SO{sub 4}) and hydrogen peroxide (H{sub 2}O{sub 2}) were used as oxidants for the chemical pre-oxidation step and unacclimatized municipal activated sludge was employed in the subsequent biodegradation step. Oxone was found to have an oxidation efficiency approximately ten-fold greater than hydrogen peroxide on a stoichiometric basis. In comparison to chemical oxidation only, a 24 hour pre-oxidation step using 5 and 10 g/L Oxone followed by a 5 day biological oxidation step enhanced removal of phenanthrene from the soil by 115% and 32%, respectively. Similarly, a 48 hour pre-oxidation step utilizing 5 and 10 g/L Oxone followed by a 5 day biological oxidation step enhanced the removal of phenanthrene from the soil by 113% and 43%, respectively. Based on this preliminary assessment, a treatment protocol that integrates a 24 hour chemical preoxidation step with 5 g/L Oxone followed by a 5 day biological oxidation step appears to be an effective combination for the remediation of this phenanthrene contaminated soil. 21 refs., 4 figs., 2 tabs.

  16. Synthesis and characterization of a novel layered tin(IV) phosphate with ion exchange properties

    SciTech Connect

    Bortun, A.I.; Bortun, L.N.; Clearfield, A.; Khainakov, S.A. |; Jaimez, E.; Garcia, J.R.

    1999-04-01

    A novel layered tin(IV) phosphate, Sn(NH{sub 4}PO{sub 4})(HPO{sub 4}){center_dot}2H{sub 2}O ({delta}-SnP-NH{sub 4}), was synthesized under mild hydrothermal conditions (190 C) in the presence of urea. The treatment of this compound with mineral acids gave a new phase of tin(IV) bis(monohydrogenphosphate), Sn(HPO{sub 4}){sub 2}{center_dot}3H{sub 2}O ({delta}-SnP-H). The layered nature of the solid was confirmed from amine intercalation, exfoliation in alkaline media, and the ion exchange behavior towards alkali and alkaline earth ions. High affinity (K{sub d}{sup Cs} {approximately} 5 {times} 10{sup 4} to 2 {times} 10{sup 5} mL g{sup {minus}1}) and capacity (160--200 mg Cs{sup +} per g of exchanger) for Cs{sup +} makes these materials promising for selective radioactive cesium removal from contaminated groundwater and nuclear waste.

  17. Measurements of hadron form factors at BESIII

    NASA Astrophysics Data System (ADS)

    Morales, Cristina Morales

    2016-05-01

    BEPCII is a symmetric e+e--collider located in Beijing running at center-of-mass energies between 2.0 and 4.6 GeV. This energy range allows the BESIII-experiment to measure hadron form factors both from direct e+e--annihilation and from initial state radiation processes. In this paper, results on e+e- → p p ¯ based on data collected by BESIII in 2011 and 2012 are presented. We also present preliminary results on e+e- → Λ Λ ¯ based on the same data samples at 4 center-of-mass energies. BESIII results obtained from e+e- → π+π- using the initial state radiation technique at the center-of-mass energy of 3.773 GeV are also summarized. Finally, expectations on the measurement of baryon electromagnetic form factors from the BESIII high luminosity energy scan in 2015 and from initial state radiation processes at different center-of-mass energies are also explained.

  18. 805 MHz Beta = 0.47 Elliptical Accelerating Structure R & D

    SciTech Connect

    S. Bricker; C. Compton; W. Hartung; M. Johnson; F. Marti; J. Popierlarski; R. C. York; et al

    2008-09-22

    A 6-cell 805 MHz superconducting cavity for acceleration in the velocity range of about 0.4 to 0.53 times the speed of light was designed. After single-cell prototyping, three 6-cell niobium cavities were fabricated. In vertical RF tests of the 6-cell cavities, the measured quality factors (Q{sub 0}) were between 7 {center_dot} 10{sup 9} and 1.4 {center_dot} 10{sup 10} at the design field (accelerating gradient of 8 to 10 MV/m). A rectangular cryomodule was designed to house 4 cavities per cryomodule. The 4-cavity cryomodule could be used for acceleration of ions in a linear accelerator, with focusing elements between the cryomodules. A prototype cryomodule was fabricated to test 2 cavities under realistic operating conditions. Two of the 6-cell cavities were equipped with helium tanks, tuners, and input coupler and installed into the cryomodule. The prototype cryomodule was used to verify alignment, electromagnetic performance, frequency tuning, cryogenic performance, low-level RF control, and control of microphonics.

  19. Structure of SiO[sub 2] on Al[sub 2]O[sub 3] monolayer catalysts: Investigation by infrared spectroscopy and [sup 29]Si MAS NMR

    SciTech Connect

    Sheng, T.C. ); Lang, S.; Morrow, B.A. ); Gay, I.D. )

    1994-07-01

    Infrared spectroscopy and [sup 29]Si MAS NMR are used to probe the structure of SiO[sub 2] on Al[sub 2]O[sub 3] catalysts prepared by chemical vapor deposition of Si(OCH[sub 3])[sub 4][center dot]SiO[sub 2] loadings from about 0.2-2.5 statistical monolayers are studied. Infrared shows a gradual disappearance of AlOH vibrations as the SiO[sub 2] loading is increased. A population of inaccessible AlOH is also observed. The Si-O-X asymmetric stretching frequency shows a continuous variation with SiO[sub 2] content, consistent with X varying from Al at low levels to Si at high levels of silica. [sup 29]Si NMR shows composite peaks at all SiO[sub 2] levels. At the lowest level most intensity is concentrated in the -80 to -85 ppm range, corresponding to Si with attached -OAl groups. At the highest silica levels, the spectrum can be deconvoluted into peaks at -108, -100, and -92 ppm. These correspond to Si(OSi)[sub 4], Si(OSi)[sub 3]OH, and mixtures of Si(OSi)[sub 2](OH)[sub 2] with -OAl-containing species. A model is proposed for build up of the silica layer on these catalysts. Random deposition of silica on any available surface is shown to give a semiquantitative account of the experimental results. 31 refs., 6 fig., 2 tabs.

  20. In situ encapsulation bench-scale demonstration report FY-94 (for TTP-ID 142012)

    SciTech Connect

    Weidner, J.R.; Shaw, P.G.

    1995-01-01

    This report describes the test objectives, procedures, and results of the laboratory-scale tests of in situ waste encapsulation of buried waste using a synthetic analogue of natural cement. The products of the reaction FeSO{sub 4} {center_dot} 7H{sub 2}O + Ca(OH){sub 2} = gypsum and iron oxide/hydroxide were examined as a possible waste encapsulation material for application at the Subsurface Disposal Area at the Idaho National Engineering Laboratory. This technique for transuranic waste encapsulation is being pursued by the Buried Waste Integrated Demonstration as a possible candidate containment and stabilization method for geologic time. The data indicate that the iron waste encapsulation materials tested are appropriate choices for the intended purpose. Based on these observations and conclusions, full-scale tests are recommended to determine the performance of the iron waste isolation materials under field conditions and for extended time periods. The viscosity of the reagents indicates that jet grouting is probably an appropriate application method.

  1. Extended universal finite-T renormalization of excitations in a class of one-dimensional quantum magnets.

    SciTech Connect

    Zheludev, Andrey I; Garlea, Vasile O; Regnault, L.-P.; Manaka, H.; Tswelik, A.

    2008-01-01

    Temperature dependencies of gap energies and magnon lifetimes are measured in the quasi-one-dimensional S=1/2 gapped quantum magnets (CH{sub 3}){sub 2}CHNH{sub 3}CuCL{sub 3} (IPA-CuCl{sub 3}, where IPA denotes isopropyl ammonium) and Cu{sub 2}Cl{sub 4} {center_dot} D{sub 8}C{sub 4}SO{sub 2} (Sul-Cu{sub 2}Cl{sub 4}) using inelastic neutron scattering. The results are compared to those found in literature for S=1 Haldane spin chain materials and to theoretical calculations for the O(3)- and O(N)- quantum nonlinear {delta}-models. It is found that when the T=0 energy gap {Delta} is used as the temperature scale, all experimental and theoretical curves are identical to within system-dependent but temperature-independent scaling factors of the order of unity. This quasi-universality extends over a surprising broad T range, at least up to {kappa}T {approx} 1.5{Delta}.

  2. Total shoulder arthroplasty outcome for treatment of osteoarthritis: a multicenter study using a contemporary implant.

    PubMed

    Wright, Thomas W; Flurin, Pierre-Henri; Crosby, Lynn; Struk, Aimee M; Zuckerman, Joseph D

    2015-11-01

    In this article, we present clinical results of primary total shoulder arthroplasty for osteoarthritis using an implant that provides dual eccentricity and variable neck and version angles for reconstruction of proximal humeral anatomy. Two hundred one patients with symptomatic osteoarthritis underwent 218 total shoulder arthroplasties with a fourth-generation anatomical shoulder and a replicator plate at 4 centers between August 1, 2006, and December 31, 2010. Fourth-generation implants allow for varying humeral neck and version angles and have dual eccentricity so as to be consistently able to cover the humeral head cut. At a mean follow-up of 3 years (minimum, 2 years), there was an 81% follow-up rate. At final follow-up, 3 objective measures were significantly (P < .05) improved over preoperative levels: average active elevation (preoperative, 92°; postoperative, 137°), active external rotation (pre, 15°; post, 42°), and active internal rotation (pre, S3; post, L2). The functional outcome scores that were significantly (P < .05) improved at final follow-up were Constant normalized (pre, 39; post, 79), Shoulder Pain and Disability Index (pre, 86; post, 20), Simple Shoulder Test (pre, 3.3; post, 10), UCLA Shoulder Rating Scale (pre, 13; post, 31), and American Shoulder and Elbow Surgeons Shoulder Assessment (pre, 33; post, 85). Complications were noted in 11% of the shoulders. The most common complications were rotator cuff failure (13, 6%) and infection (5, 2%).

  3. Separation of flue-gas scrubber sludge into marketable products. Third year, first quarterly technical progress report Quarter No. 9, September 1, 1995--November 30, 1995

    SciTech Connect

    Kawatra, S.K.; Eisele, T.C.

    1995-12-01

    To reduce their sulfur emissions, many coal-fired electric power plants use wet flue-gas scrubbers. These scrubbers convert sulfur oxides into solid sulfate and sulfite sludge, which must then be disposed of This sludge is a result of reacting limestone with sulfur dioxide to precipitate calcium sulfite and calcium sulfate. It consists of calcium sulfite (CaSO{sub 3}{center_dot}0.5H{sub 2}O), gypsum (CaSO{sub 4}{center_dot}2H{sub 2}O), and unreacted limestone (CaCO{sub 3}) or lime (Ca(OH){sub 2}), with miscellaneous objectionable impurities such as iron oxides, silicates, and magnesium, sodium, and potassium oxides or salts. These impurities prevent many sludges from being utilized as a replacement for natural gypsum, and as a result they must be disposed of in landfills, which presents a serious disposal problem. Knowledge of scrubber sludge characteristics is necessary for the development of purification technologies which will make it possible to directly utilize scrubber sludges rather than landfilling them. This project is studying the use of minimal-reagent froth flotation as the purification process, using the surface properties of the particles of unreacted limestone to remove them and their associated impurities from the material, leaving a purified calcium sulfite/gypsum product.

  4. Diamagnetic Ru(2+) in Na2La2Ti2RuO10-x (0 < x < 2): A Series of Complex Oxides Prepared by Topochemical Reduction.

    PubMed

    Pratt, Jacob A; Shepherd, Ashley M; Hayward, Michael A

    2015-11-16

    Reaction of the n = 3 Ruddlesden-Popper phase Na2La2Ti2RuO10 with a 5% H2/95% N2 atmosphere between 300 and 900 °C leads to the formation of phases of composition Na2La2Ti2RuO10-x (0 < x < 2) via topochemical reduction. Magnetization data collected from Na2La2Ti2RuO10-x samples in the range 0 < x < 1 show a rapid decline in susceptibility with increasing x, consistent with the conversion of S = 1, Ru(4+) centers at x = 0 to S = 0, Ru(2+) centers at x = 1. We believe this is the first report of diamagnetic Ru(2+) centers in an extended oxide phase. Further reduction of Na2La2Ti2RuO9 leads to the reduction of Ti(4+) to Ti(3+); however, Na2La2Ti2RuO10-x samples in the range 1 < x < 2 exhibit only a very weak paramagnetic response. Given the highly insulating nature of the phases, this suggests the electrons added on reduction of titanium are paired within a local Ti-Ti bonding network in a manner analogous to that observed for TinO2n-1 phases.

  5. Separation of Flue-Gas Scrubber Sludge into Marketable Products

    SciTech Connect

    1998-02-28

    The reduction of sulfur oxides from high sulfur coal burning utility companies has resulted in the production of huge quantities of wet flue-gas desulfurization scrubber sludge. A typical 400 MW power station burning a coal containing 3.5% sulfur by weight and using a limestone absorbent would produce approximately 177,000 tons (dry weight) of scrubber sludge per year. This brownish colored, finely divided material contains calcium sulfite (CaSO{sub 3} {center_dot} 1/2 H{sub 2}O), calcium sulfate (CaSO{sub 4} {center_dot} 2H{sub 2}O), unreacted limestone (CaCO{sub 3}), and various other impurities such as fly-ash and iron oxide particles. The physical separation of the components of scrubber sludge would result in the re-use of this material. The primary use would be conversion to a highly pure synthetic gypsum. This technical report concentrates on the effect of baffle configuration on the separation of calcium sulfite/sulfate from limestone. The position of the baffles as they related to the feed inlet, and the quantity of the baffles were examined. A clean calcium sulfite/sulfate (less than 2.0% limestone by weight) was achieved with the combination of water-only cyclone and horizontally baffled column.

  6. Recovery and utilization of gypsum and limestone from scrubber sludge. Final technical report, September 1, 1992--August 31, 1993

    SciTech Connect

    Kawatra, S.K.; Eisele, T.C.

    1993-12-31

    Wet flue-gas desulfurization units in coal-fired power plants produce a large amount of sludge which must be disposed of, and which is currently landfilled in most cases. Increasing landfill costs are gradually forcing utilities to find other alternatives. In principle, this sludge can be used to make gypsum (CaSO{sub 4}{center_dot}2H{sub 2}O) for products such as plaster-of-Paris and wallboard, but only if impurities such as unreacted limestone and soluble salts are removed, and the calcium sulfite (CaSO{sub 3}) is oxidized to calcium sulfate (CaSO{sub 4}). This project investigated methods for removing the impurities from the sludge so that high-quality, salable gypsum products can be made. Two processes were studied, both separately and in combination: Water-only cycloning, and froth flotation. A large fraction (30--40%) of the impurities in the sludge are contained in the coarser, higher-density particles, which are readily removed using a water-only cyclone. Much of the remaining impurities are hydrophobic, and can be removed by froth flotation. A combined cyclone/froth flotation process has been found to be suitable for producing a high-purity product from scrubber sludge at low cost.

  7. New Sericostomatid Caddisflies (Trichoptera) from the Brazilian Subregion

    NASA Astrophysics Data System (ADS)

    Holzenthal, R. W.; Blahnik, R. J.

    2005-05-01

    The caddisfly family Sericostomatidae, with 20 genera and almost 100 species, is nearly cosmopolitan in distribution, but is absent from the Australasian region, has only a single species in the Oriental region, and occurs only in the southernmost regions of Africa and South America. Within its distribution, it displays 4 centers of species diversity: the southeastern United States, Europe and the western Palearctic, South Africa, and southern Chile. Five genera occur in the Neotropics: Chiloecia (1 species), Grumicha (1 species), Myotrichia (1 species), Notidobiella (3 species), and Parasericostoma (10 species), all occurring in southern Chile, except Grumicha, from southeast Brazil and adjacent Argentina. Recent collecting throughout South America, but especially in SE Brazil, has resulted in the discovery of 4 new species and an extension of the family's range in South America well beyond the Chilean subregion. The new taxa include: 1 new species of Grumicha from southeastern Brazil, 2 new species of Notidobiella from SE Brazil and Ecuador, respectively, and a new species, probably representing a new genus, from Amazonian Brazil. Males, females, and immatures of these new species are described and illustrated. Biogeographical implications suggest both recent dispersal as well as more ancient Gondwanan vicariant patterns.

  8. Multiscale Assessment of Methylarsenic Reactivity in Soil. 2. Distribution and Speciation in Soil

    SciTech Connect

    M Shimizu; Y Arai; D Sparks

    2011-12-31

    Methylated forms of arsenic (As), monomethylarsenate (MMA) and dimethylarsenate (DMA), have historically been used as herbicides and pesticides. Because of their large application to agriculture fields and the toxicity of MMA and DMA, the distribution, speciation, and sorption of methylated As to soils requires investigation. Monomethylarsenate and DMA were reacted with a soil up to one year under aerobic and anaerobic conditions. Microsynchrotron based X-ray fluorescence ({mu}-SXRF) mapping studies showed that MMA and DMA were heterogeneously distributed in the soil and were mainly associated with iron oxyhydroxides, e.g., goethite, in the soil. Micro-X-ray absorption near edge structure (XANES) spectra collected from As hotspots showed MMA and DMA were demethylated to arsenate over one year incubation under aerobic conditions. Monomethylarsenate was methylated to DMA, and DMA was maintained as DMA over a 3 month incubation under anaerobic conditions. Arsenic-iron precipitation, such as the formation of scorodite (FeAsO{sub 4} {center_dot} 2H{sub 2}O), was not observed, indicating that MMA and DMA were mainly associated with Fe-oxyhydroxides as sorption complexes.

  9. Effect of Li+ ions co-doping on luminescence, scintillation properties and defects characteristics of LuAG:Ce ceramics

    NASA Astrophysics Data System (ADS)

    Liu, Shuping; Feng, Xiqi; Mares, Jiri A.; Babin, Vladimir; Hu, Chen; Kou, Huamin; D'Ambrosio, Carmelo; Li, Jiang; Pan, Yubai; Nikl, Martin

    2017-02-01

    Monovalent Li+ codoped Lu3Al5O12:Ce (LuAG:Ce) optical ceramics were fabricated by solid state reaction method and further optimized by an air-annealing process. Optical absorption, radioluminescence spectra and scintillation properties such as light yield, scintillation decay times and afterglow were measured and compared with those of the Li+ free LuAG:Ce ceramic and the commercial LuAG:Ce single crystal samples. Positive effect of Li+ codopant consists mainly in the significant increase of scintillation light yield, acceleration of scintillation decay as well as the decrease of afterglow intensity. With 0.3% Li codoping, the obtained LuAG:Ce,Li ceramic displays a light yield of ∼29200 ph/MeV at 10 μs shaping time, higher than that of the LuAG:Ce single crystal and optical ceramic scintillators ever reported. The partial conversion of the stable Ce3+ to Ce4+ centers and the shallow and deep traps effect suppression by the Li+ codoping are discussed.

  10. Design of active and stable Co-Mo-Sx chalcogels as pH-universal catalyst for the hydrogen evolution reaction.

    SciTech Connect

    Staszak-Jirkovsky, Jakub; Malliakas, Christos D.; Lopes, Pietro P.; Danilovic, Nemanja; Kota, Subrahmanyam S.; Chang, Kee-Chul; Genorio, Bostjan; Strmcnik, Dusan; Stamenkovic, Vojislav R.; Kanatzidis, Mercouri G.; Markovic, Nenad M.

    2016-02-01

    Three of the fundamental catalytic limitations that have plagued the electrochemical production of hydrogen for decades still remain: low efficiency, short lifetime of catalysts and a lack of low-cost materials. Here, we address these three challenges by establishing and exploring an intimate functional link between the reactivity and stability of crystalline (CoS2 and MoS2) and amorphous (CoSx and MoSx) hydrogen evolution catalysts. We propose that Co2+ and Mo4+ centers promote the initial discharge of water (alkaline solutions) or hydronium ions (acid solutions). We establish that although CoSx materials are more active than MoSx they are also less stable, suggesting that the active sites are defects formed after dissolution of Co and Mo cations. By combining the higher activity of CoSx building blocks with the higher stability of MoSx units into a compact and robust CoMoSx structure, we are able to design a low-cost alternative to noble metal catalysts for efficient electrocatalytic production of hydrogen in both alkaline and acidic environments.

  11. BUILDING MATERIALS MADE FROM FLUE GAS DESULFURIZATION BY-PRODUCTS

    SciTech Connect

    Michael W. Grutzeck; Maria DiCola; Paul Brenner

    2006-03-30

    Flue gas desulphurization (FGD) materials are produced in abundant quantities by coal burning utilities. Due to environmental restrains, flue gases must be ''cleaned'' prior to release to the atmosphere. They are two general methods to ''scrub'' flue gas: wet and dry. The choice of scrubbing material is often defined by the type of coal being burned, i.e. its composition. Scrubbing is traditionally carried out using a slurry of calcium containing material (slaked lime or calcium carbonate) that is made to contact exiting flue gas as either a spay injected into the gas or in a bubble tower. The calcium combined with the SO{sub 2} in the gas to form insoluble precipitates. Some plants have been using dry injection of these same materials or their own Class C fly ash to scrub. In either case the end product contains primarily hannebachite (CaSO{sub 3} {center_dot} 1/2H{sub 2}O) with smaller amounts of gypsum (CaSO{sub 4} {center_dot} 2H{sub 2}O). These materials have little commercial use. Experiments were carried out that were meant to explore the feasibility of using blends of hannebachite and fly ash mixed with concentrated sodium hydroxide to make masonry products. The results suggest that some of these mixtures could be used in place of conventional Portland cement based products such as retaining wall bricks and pavers.

  12. Synthesis and crystal structure of the coordination compound of pyridoxine with manganese sulfate

    SciTech Connect

    Furmanova, N. G. Verin, I. A.; Shyityeva, N.; Sulaimankulov, K. S.; Berdalieva, Zh.; Resnyanskii, V. F.; Duishenbaeva, A. T.

    2011-11-15

    The reaction of pyridoxine with manganese sulfate in an aqueous solution gave the coordination compound MnSO{sub 4} {center_dot} 2C{sub 8}H{sub 11}O{sub 3}N {center_dot} 2H{sub 2}O (I). The structure of I was determined from single-crystal X-ray diffraction data. In the centrosymmetric complex (sp. gr. P1-bar, Z = 1), the Mn atom is coordinated by two pyridoxine molecules and two water molecules, thus adopting an octahedral coordination. The sulfate anion is also at a center of symmetry and, consequently, is disordered. The pyridoxine molecules are coordinated to the metal atom through the oxygen atoms of the deprotonated hydroxyl group and the CH{sub 2}OH group that retains the hydrogen atom. The nitrogen atom is protonated in such a way that the heterocycle assumes a pyridinium character. The crystal structure also contains six water molecules of crystallization. A thermogravimetric study showed that the decomposition of I occurs in several successive steps, such as dehydration, the combustion of organic ligands, and the formation of an inorganic residue.

  13. Low-temperature photochromic response of phosphorus-doped bismuth silicon oxide

    NASA Astrophysics Data System (ADS)

    McCullough, J. S.; Harmon, Angela; Martin, J. J.; Martin, J. J.; Harris, M. T.; Larkin, J. J.

    1995-08-01

    Phosphorus is one of several dopants that electronically compensate the native deep donor responsible for the yellow coloration observed in bismuth silicon oxide (BSO). Low-temperature optical absorption measurements of a series of Czochralski-grown P-doped BSO crystals show that ˜0.1-0.15 at. % P is needed in the sample to fully remove the yellow coloration. The absorption cutoff in the fully compensated P-doped sample was at 3.2 eV while compensated Al- and Ga-doped samples cutoff at 3.35 eV. Excitation at 10-15 K with near band-edge light produces photochromic absorption bands. In the lightly-doped (partially bleached) samples these bands were identical to those observed in undoped BSO. In the fully bleached sample a new spectrum was observed. Its major contribution was a band centered near 1.8 eV with a weaker absorption in the blue-green. By comparison with the spectra observed in undoped and in Al-doped material before and after photoexcitation it is believed that the 1.8 eV band is due to the [PO4]- center and that the broad 2.45 eV band observed in Al- and Ga-doped BSO is due to the [BiO4]0 center.

  14. Reactivity and Mössbauer spectroscopic characterization of an Fe(IV) ketimide complex and reinvestigation of an Fe(IV) norbornyl complex.

    PubMed

    Lewis, Richard A; Smiles, Danil E; Darmon, Jonathan M; Stieber, S Chantal E; Wu, Guang; Hayton, Trevor W

    2013-07-15

    Thermolysis of Fe(N═C(t)Bu2)4 (1) for 8 h at 50 °C generates the mixed valent Fe(III)/Fe(II) bimetallic complex Fe2(N═C(t)Bu2)5 (2) in moderate yield. Also formed in this reaction are tert-butyl cyanide, isobutane, and isobutylene, the products of ketimide oxidation by the Fe(4+) center. Reaction of 1 with 1 equiv of acetylacetone affords the Fe(III) complex, Fe(N═C(t)Bu2)2(acac) (3), concomitant with formation of bis(tert-butyl)ketimine, tert-butyl cyanide, isobutane, and isobutylene. In addition, the Mössbauer spectra of 1 and its lower-valent analogues [Li(12-crown-4)2][Fe(N═C(t)Bu2)4] (5) and [Li(THF)]2[Fe(N═C(t)Bu2)4] (6) were recorded. We also revisited the chemistry of Fe(1-norbornyl)4 (4) to elucidate its solid-state molecular structure and determine its Mössbauer spectrum, for comparison with that recorded for 1.

  15. Elucidating Oxygen Reduction Active Sites in Pyrolyzed Metal–Nitrogen Coordinated Non-Precious-Metal Electrocatalyst Systems

    PubMed Central

    2015-01-01

    Detailed understanding of the nature of the active centers in non-precious-metal-based electrocatalyst, and their role in oxygen reduction reaction (ORR) mechanistic pathways will have a profound effect on successful commercialization of emission-free energy devices such as fuel cells. Recently, using pyrolyzed model structures of iron porphyrins, we have demonstrated that a covalent integration of the Fe–Nx sites into π-conjugated carbon basal plane modifies electron donating/withdrawing capability of the carbonaceous ligand, consequently improving ORR activity. Here, we employ a combination of in situ X-ray spectroscopy and electrochemical methods to identify the various structural and functional forms of the active centers in non-heme Fe/N/C catalysts. Both methods corroboratively confirm the single site 2e– × 2e– mechanism in alkaline media on the primary Fe2+–N4 centers and the dual-site 2e– × 2e– mechanism in acid media with the significant role of the surface bound coexisting Fe/FexOy nanoparticles (NPs) as the secondary active sites. PMID:24817921

  16. Uranyl fluoride luminescence in acidic aqueous solutions

    SciTech Connect

    Beitz, J.V.; Williams, C.W.

    1996-08-01

    Luminescence emission spectra and decay rates are reported for uranyl species in acidic aqueous solutions containing HF or added NaF. The longest luminescence lifetime, 0.269 {+-} 0.006 ms, was observed from uranyl in 1 M HF + 1 M HClO{sub 4} at 296 K and decreased with increasing temperature. Based on a luminescence dynamics model that assumes equilibrium among electronically excited uranyl fluoride species and free fluoride ion, this long lived uranyl luminescence in aqueous solution is attributed primarily to UO{sub 2}F{sub 2}. Studies on the effect of added LiNO{sub 3} or Na{sub 2}WO{sub 4}{center_dot}2H{sub 2}O showed relatively weak quenching of uranyl fluoride luminescence which suggests that high sensitivity determination of the UF{sub 6} content of WF{sub 6} gas should be feasible via uranyl luminescence analysis of hydrolyzed gas samples of impure WF{sub 6}.

  17. Follicular lymphoma cell niche: identification of a preeminent IL-4-dependent T(FH)-B cell axis

    PubMed Central

    Pangault, Céline; Amé-Thomas, Patricia; Ruminy, Philippe; Rossille, Delphine; Caron, Gersende; Baia, Maryse; De Vos, John; Roussel, Mikael; Monvoisin, Céline; Lamy, Thierry; Tilly, Hervé; Gaulard, Philippe; Tarte, Karin; Fest, Thierry

    2010-01-01

    Follicular lymphoma (FL) B cells contract tight connections with their microenvironment, which governs the pathogenesis and progression of the disease. Indeed, specific immune response gene signatures, obtained on whole biopsy samples, have been associated with patient survival. In this study we performed gene expression profiling of purified B-cell and non-B cell compartments obtained from FL and reactive lymph nodes. We identified 677 nonredundant genes defining the FL interface and involving 26 FL-specific functional networks. This approach highlighted an IL-4-centered pathway associated with an activation of STAT6 that favors overexpression of IL-4-target genes. In addition, FL microenvironment was characterized by a strong enrichment in follicular helper T cells (TFH), as demonstrated through transcriptomic and flow cytometry analyses. The majority of phospho-STAT6pos B cells were located at the vicinity of cells expressing the PD-1 TFH marker. Moreover, purified FL-derived TFH, expressed IL4 at very high levels compared to purified tonsil-derived TFH or non-TFH microenvironment. Altogether, our study demonstrated that tumor-infiltrating TFH specifically express functional IL-4 in FL, creating an IL-4-dependent TFH-B cell axis. This crosstalk could sustain FL pathogenesis and represent a new potential therapeutic target. PMID:20944673

  18. SYNTHESIS OF SULFUR-BASED WATER TREATMENT AGENT FROM SULFUR DIOXIDE WASTE STREAMS

    SciTech Connect

    Robert C. Brown; Maohong Fan; Adrienne Cooper

    2002-10-01

    Absorption of sulfur dioxide from a simulated flue gas was investigated for the production of polymeric ferric sulfate (PFS), a highly effective coagulant useful in treatment of drinking water and wastewater. The reaction for PFS synthesis took place near atmospheric pressure and at temperatures of 30-80 C. SO{sub 2} removal efficiencies greater than 90% were achieved, with ferrous iron concentrations in the product less than 0.1%. A factorial analysis of the effect of temperature, oxidant dosage, SO{sub 2} concentration, and gas flow rate on SO{sub 2} removal efficiency was carried out, and statistical analyses are conducted. The solid PFS was also characterized with different methods. Characterization results have shown that PFS possesses both crystalline and non-crystalline structure. The kinetics of reactions among FeSO{sub 4} {center_dot} 7H{sub 2}O, NaHSO{sub 3} and NaClO{sub 3} was investigated. The PFS product was used in pilot-scale tests at a municipal water treatment facility and gave good results in removal of turbidity and superior results in removal of disinfection byproduct precursors (TOC, DOC, UV-254) when compared with equal doses of ferric chloride.

  19. Use of Mini-Grant to Disseminate Evidence-Based Interventions for Cancer Prevention and Control.

    PubMed

    Kegler, Michelle C; Carvalho, Michelle L; Ory, Marcia; Kellstedt, Deb; Friedman, Daniela B; McCracken, James Lyndon; Dawson, Glenna; Fernandez, Maria

    2015-01-01

    Mini-grants are an increasingly common tool for engaging communities in evidence-based interventions for promoting public health. This article describes efforts by 4 Centers for Disease Control and Prevention/National Cancer Institute-funded Cancer Prevention and Control Research Network centers to design and implement mini-grant programs to disseminate evidence-based interventions for cancer prevention and control. This article also describes source of evidence-based interventions, funding levels, selection criteria, time frame, number and size of grants, types of organizations funded, selected accomplishments, training and technical assistance, and evaluation topics/methods. Grant size ranged from $1000 to $10 000 (median = $6250). This mini-grant opportunity was characterized by its emphasis on training and technical assistance for evidence-based programming and dissemination of interventions from National Cancer Institute's Research-Tested Intervention Programs and Centers for Disease Control and Prevention's Guide to Community Preventive Services. All projects had an evaluation component, although they varied in scope. Mini-grant processes described can serve as a model for organizations such as state health departments working to bridge the gap between research and practice.

  20. Resonant planar antenna as an inductive plasma source

    SciTech Connect

    Guittienne, Ph.; Lecoultre, S.; Howling, A. A.; Hollenstein, Ch.; Fayet, P.; Larrieu, J.

    2012-04-15

    A resonant planar antenna as an inductive plasma source operating at 13.56 MHz inside a low pressure vacuum vessel is presented for potential plasma processing applications. Its principle consists in interconnecting elementary resonant meshes composed of inductive and capacitive elements. Due to its structure, the antenna shows a set of resonant modes associated with peaks of the real input impedance. Each of these modes is defined by its own current and voltage distribution oscillating at the frequency of the mode. A rectangular antenna of 0.55mx0.20m has been built, and first results obtained with argon plasmas are presented. Plasma generation is shown to be efficient as densities up to 4{center_dot}10{sup 17}m{sup -3} at 2000 W have been measured by microwave interferometry at a distance of 4 cm from the source plane. It is also demonstrated that the plasma couples inductively with the resonating currents flowing in the antenna above a threshold power of about 60 W. A non-uniformity of less than {+-}5% is obtained at 1000 W at a few centimeters above the antenna over 75% of its surface.

  1. The effect of the Syrian crisis on organ transplantation in Syria.

    PubMed

    Saeed, Bassam

    2015-04-01

    The war in Syria that started in March 2011 has destroyed much of the country's infrastructure including many hospitals. The total number of kidney transplants performed in Syria in 2010 was 385 transplants before the number gradually declined to 154 transplants in 2013, a decrease of 60%. In addition, the number of operational kidney transplant centers has decreased from 8 to 4 centers. Unrelated-donor kidney transplant decreased from 70% during the years that preceded the crisis to 47% in 2013. More than 50% of physicians and surgeons involved in kidney transplant are not practicing transplant currently in their centers. Difficulties in the provision of immunosuppressive drugs for all patients in all provinces constitute a major challenge for the health authorities and transplant patients, especially patients who cannot arrange an alternate source. The project to initiate liver transplant came to a halt because foreign trainers could not visit Syria. The autologous bone marrow transplant program continued to function, but in a smaller and irregular manner. The commitment of transplant teams despite the large challenges was, and still is, extraordinary. In conclusion, all aspects of organ transplant have been affected, paralyzing new projects and negatively affecting existing programs.

  2. Reinforcing of QA/QC programs in radiotherapy departments in Croatia: Results of treatment planning system verification

    SciTech Connect

    Jurković, Slaven; Švabić, Manda; Diklić, Ana; Smilović Radojčić, Đeni; Dundara, Dea; Kasabašić, Mladen; Ivković, Ana; Faj, Dario

    2013-04-01

    Implementation of advanced techniques in clinical practice can greatly improve the outcome of radiation therapy, but it also makes the process much more complex with a lot of room for errors. An important part of the quality assurance program is verification of treatment planning system (TPS). Dosimetric verifications in anthropomorphic phantom were performed in 4 centers where new systems were installed. A total of 14 tests for 2 photon energies and multigrid superposition algorithms were conducted using the CMS XiO TPS. Evaluation criteria as specified in the International Atomic Energy Agency Technical Reports Series (IAEA TRS) 430 were employed. Results of measurements are grouped according to the placement of the measuring point and the beam energy. The majority of differences between calculated and measured doses in the water-equivalent part of the phantom were in tolerance. Significantly more out-of-tolerance values were observed in “nonwater-equivalent” parts of the phantom, especially for higher-energy photon beams. This survey was done as a part of continuous effort to build up awareness of quality assurance/quality control (QA/QC) importance in the Croatian radiotherapy community. Understanding the limitations of different parts of the various systems used in radiation therapy can systematically improve quality as well.

  3. Surface nature of nanoparticle zinc-titanium oxide aerogel catalysts

    NASA Astrophysics Data System (ADS)

    Wang, Chien-Tsung; Lin, Jen-Chieh

    2008-05-01

    Nanoparticle zinc-titanium oxide materials were prepared by the aerogel approach. Their structure, surface state and reactivity were investigated. Zinc titanate powders formed at higher zinc loadings possessed a higher surface area and smaller particle size. X-ray photoelectron spectroscopy (XPS) revealed a stronger electronic interaction between Zn and Ti atoms in the mixed oxide structure and showed the formation of oxygen vacancy due to zinc doping into titania or zinc titanate matrices. The 8-45 nm aerogel particles were evaluated as catalysts for methanol oxidation in an ambient flow reactor. Carbon dioxide was favorably produced on the oxides with anion defects. Titanium based oxides exhibited a high selectivity to dimethyl ether, so that a strong Lewis acidic character suggested for the catalysts was associated primarily with the Ti 4+ center. Both methanol conversion and dimethyl ether formation rates increased with increasing the zinc content added to the oxide support. Results demonstrate that cubic zinc titanate phases produce new Lewis acid sites having also a higher reactivity and that the nature of the catalytic surface transforms from Lewis acidic to basic characters due to the presence of reactive oxygen vacancies.

  4. Results of Propellant Mixing Variable Study Using Precise Pressure-Based Burn Rate Calculations

    NASA Technical Reports Server (NTRS)

    Stefanski, Philip L.

    2014-01-01

    A designed experiment was conducted in which three mix processing variables (pre-curative addition mix temperature, pre-curative addition mixing time, and mixer speed) were varied to estimate their effects on within-mix propellant burn rate variability. The chosen discriminator for the experiment was the 2-inch diameter by 4-inch long (2x4) Center-Perforated (CP) ballistic evaluation motor. Motor nozzle throat diameters were sized to produce a common targeted chamber pressure. Initial data analysis did not show a statistically significant effect. Because propellant burn rate must be directly related to chamber pressure, a method was developed that showed statistically significant effects on chamber pressure (either maximum or average) by adjustments to the process settings. Burn rates were calculated from chamber pressures and these were then normalized to a common pressure for comparative purposes. The pressure-based method of burn rate determination showed significant reduction in error when compared to results obtained from the Brooks' modification of the propellant web-bisector burn rate determination method. Analysis of effects using burn rates calculated by the pressure-based method showed a significant correlation of within-mix burn rate dispersion to mixing duration and the quadratic of mixing duration. The findings were confirmed in a series of mixes that examined the effects of mixing time on burn rate variation, which yielded the same results.

  5. The characteristic photoluminescence and EPR features of superdeep diamonds (São-Luis, Brazil)

    NASA Astrophysics Data System (ADS)

    Yuryeva, Olga P.; Rakhmanova, Mariana I.; Nadolinny, Vladimir A.; Zedgenizov, Dmitry A.; Shatsky, Vladislav S.; Kagi, Hiroyuki; Komarovskikh, Andrey Yu.

    2015-10-01

    Photoluminescence (PL) spectroscopy and electron paramagnetic resonance (EPR) were used for the first time to characterize properties of superdeep diamonds from the São-Luis alluvial deposits (Brazil). The infrared measurements showed the low nitrogen content (>50 of 87 diamonds from this locality were nitrogen free and belonged to type IIa) and simultaneously the extremely high level of nitrogen aggregation (pure type IaB being predominant), which indicates that diamonds under study might have formed under high pressure and temperature conditions. In most cases, PL features excited at various wavelengths (313, 473, and 532 nm) were indicative of different growth and post-growth processes during which PL centers could be formed via interaction between vacancies and nitrogen atoms. The overall presence of the 490.7 nm, H3, and H4 centers in the luminescence spectra attests to strong plastic deformations in these diamonds. The neutral vacancy known as the GR1 center has probably occurred in a number of crystals due to radiation damage in the post-growth period. The 558.5 nm PL center is found to be one of the most common defects in type IIa samples which is accompanied by the EPR center with g-factor of 2.00285. The 536 and 576 nm vibronic systems totally dominated the PL spectra of superdeep diamonds, while none of "normal" diamonds from the Mir pipe (Yakutia) with similar nitrogen characteristics showed the latter three PL centers.

  6. Elucidating Oxygen Reduction Active Sites in Pyrolyzed Metal-Nitrogen Coordinated Non-Precious-Metal Electrocatalyst Systems.

    PubMed

    Tylus, Urszula; Jia, Qingying; Strickland, Kara; Ramaswamy, Nagappan; Serov, Alexey; Atanassov, Plamen; Mukerjee, Sanjeev

    2014-05-01

    Detailed understanding of the nature of the active centers in non-precious-metal-based electrocatalyst, and their role in oxygen reduction reaction (ORR) mechanistic pathways will have a profound effect on successful commercialization of emission-free energy devices such as fuel cells. Recently, using pyrolyzed model structures of iron porphyrins, we have demonstrated that a covalent integration of the Fe-N x sites into π-conjugated carbon basal plane modifies electron donating/withdrawing capability of the carbonaceous ligand, consequently improving ORR activity. Here, we employ a combination of in situ X-ray spectroscopy and electrochemical methods to identify the various structural and functional forms of the active centers in non-heme Fe/N/C catalysts. Both methods corroboratively confirm the single site 2e(-) × 2e(-) mechanism in alkaline media on the primary Fe(2+)-N4 centers and the dual-site 2e(-) × 2e(-) mechanism in acid media with the significant role of the surface bound coexisting Fe/Fe x O y nanoparticles (NPs) as the secondary active sites.

  7. A systematic approach to prioritize drug targets using machine learning, a molecular descriptor-based classification model, and high-throughput screening of plant derived molecules: a case study in oral cancer.

    PubMed

    Randhawa, Vinay; Kumar Singh, Anil; Acharya, Vishal

    2015-12-01

    Systems-biology inspired identification of drug targets and machine learning-based screening of small molecules which modulate their activity have the potential to revolutionize modern drug discovery by complementing conventional methods. To utilize the effectiveness of such pipelines, we first analyzed the dysregulated gene pairs between control and tumor samples and then implemented an ensemble-based feature selection approach to prioritize targets in oral squamous cell carcinoma (OSCC) for therapeutic exploration. Based on the structural information of known inhibitors of CXCR4-one of the best targets identified in this study-a feature selection was implemented for the identification of optimal structural features (molecular descriptor) based on which a classification model was generated. Furthermore, the CXCR4-centered descriptor-based classification model was finally utilized to screen a repository of plant derived small-molecules to obtain potential inhibitors. The application of our methodology may assist effective selection of the best targets which may have previously been overlooked, that in turn will lead to the development of new oral cancer medications. The small molecules identified in this study can be ideal candidates for trials as potential novel anti-oral cancer agents. Importantly, distinct steps of this whole study may provide reference for the analysis of other complex human diseases.

  8. Structure and photoluminescence properties of rare-earth free narrow-band red-emitting Mg6ZnGeGa2O12: Mn4+ phosphor excited by NUV light

    NASA Astrophysics Data System (ADS)

    Ding, Xin; Wang, Yuhua

    2017-02-01

    A kind novel red emission Mg6ZnGeGa2O12: Mn4+ phosphor under NUV excitation is synthesized successfully by high temperature solid-state reaction. The structure of Mg6ZnGeGa2O12 is investigated by TEM and X-ray powder diffraction (XRD) Rietveld Refinement; the luminescence properties are measured by diffuse reflection spectra, emission spectra, excitation spectra, decay curves and temperature dependence spectra. The result indicated that it has one octahedral site and tetrahedral site in crystal structure. Mn4+ can occupy octahedral (Mg2+(Zn2+)/Ga3+) site. It can emit red light peaking at 660 nm under NUV (420 nm) excitation. The critical quenching concentration of Mn4+ was about 1.0 mol%. The concentration quenching mechanism investigates to be a d-d interaction for the Mn4+ center. The CIE chromaticity coordinates and FWHM are (0.717, 0.283) and 25 nm. The PL intensity of Mg6ZnGeGa2O12: 1.0%Mn4+ drops to 75% when the temperature is raised up to 150 °C. It implies that Mg6ZnGeGa2O12: Mn4+ is a potential red phosphor matching NUV LED chips.

  9. Simulation of Adsorption of Carbon Dioxide and Methane on Graphene Sheet

    NASA Astrophysics Data System (ADS)

    Maiga, Sidi; Gatica, Silvina

    Carbon dioxide (CO2) and Methane (CH4) constitute 90% of the annual greenhouse emission. These gases are emitted from multitude of sources such as: power station, transportation fuels, industrial processes, and agricultural byproducts. Scientists around the globe are looking for materials capable of capturing, separating, and storing these gases. Graphene with its high specific surface area provides a great platform for gas adsorption and separation. Adsorption is defined as the attachment of atoms, or molecules of a gas, liquid or dissolved solid onto a surface, creating a film or monolayer of material onto the adsorbing surface. Using the Method of Grand Canonical Monte Carlo, we computed the adsorption of carbon dioxide (CO2) and methane (CH4) on a monolayer graphene sheet, at various temperatures for each gas. For each temperature, we compute the adsorption isotherm, Energy gas-surface and Energy gas-gas. We compare the uptake pressures of CO2 and CH4. Using the Ideal Adsorbed Solution Theory (IAST), we predict the selectivity of a mixture CO2/CH4. Center for Integrated Quantum Materials (CIQM), NSF Grant No. DMR-1231319.

  10. A rat CD4 mutant containing the gp120-binding site mediates human immunodeficiency virus type 1 infection

    PubMed Central

    1993-01-01

    CD4 is the primary receptor for the human immunodeficiency virus type 1 (HIV-1). Early mutational studies implicated a number of residues of CD4, centered in the region 41-59, in binding to gp120. However, further mutational analyses, together with studies using inhibitory antibodies or CD4-derived peptides, have suggested that other regions of CD4 are also involved in binding or postbinding events during infection. To resolve these ambiguities, we used rat CD4 mutants in which particular regions were replaced with the corresponding sequence of human CD4. We have previously shown that some of these are able to bind HIV-1 gp120, and here we test their ability to act as functional receptors. We find that the presence of human CD4 residues 33-62 is enough to confer efficient receptor function to rat CD4, and we conclude that it is unlikely that regions of CD4 outside this sequence are involved in specific interactions with HIV-1 during either infection or syncytium formation. PMID:8459222

  11. Excitonic-type polaron states: photoluminescence in SBN and in other ferroelectric oxides

    NASA Astrophysics Data System (ADS)

    Vikhnin, V. S.; Kislova, I.; Kutsenko, A. B.; Kapphan, S. E.

    2002-07-01

    A theoretical model for two characteristic photoluminescence (PL) bands in SBN, 'green luminescence' and 'red luminescence' is proposed on the basis of the extended photoluminescence experiments in SBN:Cr, and also in SBN:Ce and in nominally pure SBN systems under different conditions. While the RL-band is suggested to be connected with charge transfer vibronic exciton (CTVE) clusters induced by Cr3+ impurities in the Nb-sites, the GL- band is connected with Nb4+ electronic polarons in a new, charge transfer excited states. Here Nb4+ centers are the cores of the CTVE clusters induced by these charged scores. The PL mechanism is the in-cluster CTVE recombination for both bands under discussion. But the CTVE states are quasi-resonantly mixed here with 4T2 states of the Cr3+ core in the RL-band case, and with 5s-states of the Nb4+ core in the GL-band case. The role of excitonic polarons of CTVE nature is also discussed in connection with 'green' luminescence origin in KTaO3 and KNbO3 crystals.

  12. A novel analytical method for the determination of residual moisture in plutonium dioxide: Supercritical fluid extraction/Fourier transform infrared spectroscopy

    SciTech Connect

    Martinez, A.M.; Hollis, W.K.; Rubin, J.B.; Taylor, C.M.V.; Jasperson, M.N.; Vance, D.E.; Rodriguez, J.B.

    1999-02-01

    A novel approach has been developed at the Los Alamos National Laboratory for the quantitative determination of moisture content in impure plutonium oxide. The method combines a commercial supercritical fluid extraction instrument using supercritical carbon dioxide (SCCO{sub 2}) with on-line detection using a high-pressure Fourier Transform Infrared Spectroscopy (FTIR) cell. The combined SCCO{sub 2}/FTIR system has been modified for use inside a fully enclosed glove box. A series of validation experiments were performed using a pure, surrogate oxide (ThO{sub 2}) and an inorganic hydrate (CaSO{sub 4}{center_dot}2H{sub 2}O). The level of agreement between LOI and SCCO{sub 2}/FTIR for the surrogate oxide is excellent. The results for the inorganic hydrate showed excellent correlation with the known amount of water present. Results obtained for a group of nominally pure PuO{sub 2} samples were verified by independent measurement. The results of SCCO{sub 2}/FTIR for impure PuO{sub 2} samples is consistently lower than the results of obtained from the current analytical method (Loss On Ignition), indicating that the current method is inadequate for analytical purposes. While further verification experiments of the SCCO{sub 2}/FTIR method are underway, these initial results suggest that SCCO{sub 2}/FTIR could be used as an alternative analytical method for the Materials Identification and Surveillance program.

  13. Hydrothermal reactions of fly ash. Final report

    SciTech Connect

    Brown, P.W.

    1995-12-31

    The emphasis of the work done has been to determine the reactivities of two ashes believed to be representative of those generated. A bituminous ash and a lignitic ash have been investigated. The reactions of these ashes undergo when subjected to mild hydrothermal conditions were explored. The nature of the reactions which the ashes undergo when alkaline activators, calcium hydroxide and calcium sulfate are present was also investigated. It was determined that calcium silicate hydrate, calcium aluminate hydrate, and the calcium sulfoaluminate hydrate ettringite form under these conditions. It appears 3CaO{center_dot}Al{sub 2}O{sub 3}{center_dot}3CaSO{sub 4}{center_dot}32H{sub 2}O (ettringite) formation needs to be considered in ashes which contain significant amounts of sulfate. Therefore the stability region for ettringite was established. It was also determined that calcium silicate hydrate, exhibiting a high internal surface area, will readily form with hydrothermal treatment between 50{degrees} and 100{degrees}C. This phase is likely to have a significant capacity to take up heavy metals and oxyanions and this ability is being explored.

  14. Weathering rates of marble in laboratory and outdoor conditions

    SciTech Connect

    Yerrapragada, S.S.; Chirra, S.R.; Jaynes, J.H.; Bandyopadhyay, J.K.; Gauri, K.L.; Li, S.

    1996-09-01

    In the modern urban atmosphere SO{sub 2} and NO{sub 2} attack calcite (CaCO{sub 3}) in marble exposed at rain-sheltered surfaces creating largely gypsum (CaSO{sub 4}{center_dot}2H{sub 2}O) crusts that eventually exfoliate. In combination with CO{sub 2} these gases erode the marble at unsheltered surfaces. the authors report the development of mathematical models to predict the rate of growth of crust and the rate of surface recession. To determine the rate of growth of crust the kinetic rate constant, diffusion rate, and the order of reaction were determined by the application of the shrinking-core model applied to data generated in laboratory experiments. Based on these parameters /and average ambient levels of 10 parts per billion (ppb) SO{sub 2} and 25 ppb NO{sub 2} in Louisville, Ky., the rate of crust formation for this metro area was calculated to be 1.8 {micro}m in the first year. However, the rate of recession was modeled from data obtained by exposing marble slabs to rainfalls. A surface recession of 15 {micro}m/yr was calculated. The models predicted well the rate of growth of crust observed at several sites in Louisville and the predicted surface recession compared well with values reported in the literature.

  15. Uptake of chloride and carbonate ions by calcium monosulfoaluminate hydrate

    SciTech Connect

    Mesbah, Adel; Cau-dit-Coumes, Celine; Frizon, Fabien

    2012-08-15

    Decommissioning of old nuclear reactors may produce waste streams containing chlorides and carbonates, including radioactive {sup 36}Cl{sup -} and {sup 14}CO{sub 3}{sup 2-}. Their insolubilization by calcium monosulfoaluminate hydrate was investigated. Carbonates were readily depleted from the solution, giving at thermodynamic equilibrium monocarboaluminate, monocarboaluminate + calcite, or calcite only, depending on the initial ratio between the anion and calcium monosulfoaluminate hydrate. Chloride ions reacted more slowly and were precipitated as Kuzel's salt, Kuzel's and Friedel's salts, or Friedel's salt only. Rietveld refinement of X-Ray powder diffraction patterns was successfully used to quantify the phase distributions, which were compared to thermodynamic calculations. Moreover, analysing the lattice parameters of Kuzel's salt as a function of its chloride content showed the occurrence of a restricted solid solution towards the sulfate side with general formula 3CaO{center_dot}Al{sub 2}O{sub 3}{center_dot}xCaCl{sub 2}{center_dot}(1 - x)CaSO{sub 4}{center_dot}(12 - 2x){center_dot}H{sub 2}O (0.36 {<=} x {<=} 0.50).

  16. Increased fluorescence intensity in CaTiO3:Pr3+ phosphor due to NH3 treatment and Nb Co-doping

    DOE PAGES

    Holliday, K. S.; Kohlgruber, T. A.; Tran, I. C.; ...

    2016-08-28

    Development of next generation red phosphors for commercial lighting requires understanding of how increased luminescence is achieved by various treatment strategies. In our work, we compare co-doping with Nb to NH3 treatment of CaTiO3:Pr phosphors to reveal a general mechanism responsible for the increased luminescence. The phosphors were synthesized using standard solid-state synthesis techniques and the fluorescence was characterized for potential use in fluorescent lighting, with 254 nm excitation. The lifetime of the fluorescence was determined and used to identify a change in a trap state by the co-doping of Nb5+ in the phosphor. Furthermore, the oxidation state of themore » Pr was probed by NEXAFS and revealed that both Nb5+ co-doping and NH3 treatment reduced the number of non-fluorescing Pr4+ centers. We performed calculations in order to determine the energetically favorable defects. Vacuum annealing was also used to further probe the nature of the trap state. It was determined that NH3 treatments reduce the number of Pr4+ non-fluorescing centers, while Nb5+ co-doping additionally reduces the number of excess oxygen trap states that quench the fluorescence.« less

  17. Solubility of triuranyl diphosphate tetrahydrate (TDT) and Na autunite at 23 and 50 degrees C

    SciTech Connect

    Armstrong, Christopher R.; Felmy, Andrew R.; Clark, Sue B.

    2010-11-01

    In this report we present experimental solubility data for well-characterized triuranyl diphosphate tetrahydrate (TDT: (UO2)(3)(PO4)(2)center dot 4H(2)O) and Na autunite (Na[UO2PO4]center dot xH(2)O) at 23 and 50 degrees C in NaClO4-HClO4 solutions at pC(H+) = 2. Duplicate samples of TDT in 0.1, 0.5, 1.0, 2.0 and 5.0 in solutions were equilibrated at 23 and 50 degrees C. TDT solid was synthesized and characterized with ICP-OES, ATR-IR and powder XRD before and after solubility experiments. The pH of the suspensions were monitored throughout the experiments. Equilibrium was achieved from undersaturation with respect to TDT and oversaturation for Na autunite. Steady-state conditions were achieved in all cases within 82 d. TDT was unstable at ionic strengths above 0.1 m, where its complete conversion to Na autunite was observed. The ion-interaction model was used to interpret the experimental solubility data. The solubility product, log K-sp, for TDT was determined to be -49.7 and -51.3 at 23 and 50 degrees C respectively. log K for Na autunite was determined to be -24.4 (23 degrees C) and -24.1 +/- 0.2 (50 degrees C).

  18. Dynamic HypA zinc site is essential for acid viability and proper urease maturation in Helicobacter pylori

    PubMed Central

    Johnson, Ryan C.; Hu, Heidi Q.; Merrell, D. Scott; Maroney, Michael J.

    2015-01-01

    Helicobacter pylori requires urease activity in order to survive in the acid environment of the human stomach. Urease is regulated in part by nickelation, a process that requires the HypA protein, which is a putative nickel metallochaperone that is generally associated with hydrogenase maturation. However, in H. pylori, HypA plays a dual role. In addition to an N-terminal nickel binding site, HypA proteins also contain a structural zinc site that is coordinated by two rigorously conserved CXXC sequences, which in H. pylori are flanked by His residues. These structural Zn sites are known to be dynamic, converting from Zn(Cys)4 centers at pH 7.2 to Zn(Cys)2(His)2 centers at pH 6.3 in the presence of Ni(II) ions. In this study, mutant strains of H. pylori that express zinc site variants of the HypA protein are used to show that the structural changes in the zinc site are important for the acid viability of the bacterium, and that a reduction in acid viability in these variants can be traced in large measure to deficient urease activity. This in turn leads to a model that connects the Zn(Cys)4 coordination to urease maturation. PMID:25608738

  19. Influence of the Torsion Angle in 3,3'-Dimethyl-2,2'-bipyridine on the Intermediate Valence of Yb in (C5Me5)2 Yb(3,3'-Me2-bipy)

    SciTech Connect

    Nocton, Grégory; Booth, Corwin H.; Maron, Laurent; Andersen, Richard A.

    2014-06-26

    The synthesis and X-ray crystal structures of Cp-2*Yb(3,3'-Me(2)bipy) and [Cp-2 Yb(3,3'-Me(2)bipy)][Cp-2 YbCl1.6I0.4]center dot CH2Cl2 are described. In both complexes, the NCCN torsion angles are approximately 40 degrees. The temperature-independent value of n(f) of 0.17 shows that the valence of ytterbium in the neutral adduct is multiconfigurational, in reasonable agreement with a CASSCF calculation that yields a n(f) value of 0.27; that is, the two configurations in the wave function are f(13)(pi(1))(1) and f(14)(pi(1))(0) in a ratio of 0.27:0.73, respectively, and the open-shell singlet lies 0.28 eV below the triplet state (n(f) accounts for f-hole occupancy; that is, n(f) = 1 when the configuration is f(13) and n(f) = 0 when the configuration is f(14)). A correlation is outlined between the value of nf and the individual ytterbocene and bipyridine fragments such that, as the reduction potentials of the ytterbocene cation and the free x,x'-R-2-bipy ligands approach each other, the value of nf and therefore the f(13):f(14) ratio reaches a maximum; conversely, the ratio is minimized as the disparity increases.

  20. Changes in Zinc Speciation with Mine Tailings Acidification in a Semiarid Weathering Environment

    SciTech Connect

    Hayes, Sarah M.; O’Day, Peggy A.; Webb, Sam M.; Maier, Raina M.; Chorover, Jon

    2012-10-09

    High concentrations of residual metal contaminants in mine tailings can be transported easily by wind and water, particularly when tailings remain unvegetated for decades following mining cessation, as is the case in semiarid landscapes. Understanding the speciation and mobility of contaminant metal(loid)s, particularly in surficial tailings, is essential to controlling their phytotoxicities and to revegetating impacted sites. In prior work, we showed that surficial tailings samples from the Klondyke State Superfund Site (AZ, USA), ranging in pH from 5.4 to 2.6, represent a weathering series, with acidification resulting from sulfide mineral oxidation, long-term Fe hydrolysis, and a concurrent decrease in total (6000 to 450 mg kg{sup -1}) and plant-available (590 to 75 mg kg{sup -1}) Zn due to leaching losses and changes in Zn speciation. Here, we used bulk and microfocused Zn K-edge X-ray absorption spectroscopy (XAS) data and a six-step sequential extraction procedure to determine tailings solid phase Zn speciation. Bulk sample spectra were fit by linear combination using three references: Zn-rich phyllosilicate (Zn{sub 0.8}talc), Zn sorbed to ferrihydrite (Zn{sub adsFeOx}), and zinc sulfate (ZnSO{sub 4} {center_dot} 7H{sub 2}O). Analyses indicate that Zn sorbed in tetrahedral coordination to poorly crystalline Fe and Mn (oxyhydr)oxides decreases with acidification in the weathering sequence, whereas octahedral zinc in sulfate minerals and crystalline Fe oxides undergoes a relative accumulation. Microscale analyses identified hetaerolite (ZnMn{sub 2}O{sub 4}), hemimorphite (Zn{sub 4}Si{sub 2}O{sub 7}(OH){sub 2} {center_dot} H{sub 2}O) and sphalerite (ZnS) as minor phases. Bulk and microfocused spectroscopy complement the chemical extraction results and highlight the importance of using a multimethod approach to interrogate complex tailings systems.

  1. The influence of zinc(II) on thioredoxin/glutathione disulfide exchange: QM/MM studies to explore how zinc(II) accelerates exchange in higher dielectric environments.

    PubMed

    Kurian, Roby; Bruce, Mitchell R M; Bruce, Alice E; Amar, François G

    2015-08-01

    QM/MM studies were performed to explore the energetics of exchange reactions of glutathione disulfide (GSSG) and the active site of thioredoxin [Cys32-Gly33-Pro34-Cys35] with and without zinc(II), in vacuum and solvated models. The activation energy for exchange, in the absence of zinc, is 29.7 kcal mol(-1) for the solvated model. This is 3.3 kcal mol(-1) higher than the activation energy for exchange in the gas phase, due to ground state stabilization of the active site Cys-32 thiolate in a polar environment. In the presence of zinc, the activation energy for exchange is 4.9 kcal mol(-1) lower than in the absence of zinc (solvated models). The decrease in activation energy is attributed to stabilization of the charge-separated transition state, which has a 4-centered, cyclic arrangement of Zn-S-S-S with an estimated dipole moment of 4.2 D. A difference of 4.9 kcal mol(-1) in activation energy would translate to an increase in rate by a factor of about 4000 for zinc-assisted thiol-disulfide exchange. The calculations are consistent with previously reported experimental results, which indicate that metal-thiolate, disulfide exchange rates increase as a function of solvent dielectric. This trend is opposite to that observed for the influence of the dielectric environment on the rate of thiol-disulfide exchange in the absence of metal. The results suggest a dynamic role for zinc in thiol-disulfide exchange reactions, involving accessible cysteine sites on proteins, which may contribute to redox regulation and mechanistic pathways during oxidative stress.

  2. A multicenter prospective trial evaluating fetal bovine dermal graft (Xenform® Matrix) for pelvic reconstructive surgery

    PubMed Central

    2010-01-01

    Background A prospective multicenter clinical study was performed to evaluate the safety and efficacy of a bovine dermal graft (Xenform® Matrix, Boston Scientific, Natick, MA, USA) during vaginal reconstructive surgery. Methods Forty-five women with ICS stage 2 or higher pelvic organ prolapse (POP) were enrolled at 4 centers. POP-Q, pelvic floor function (PFDI-20), sexual function (PISQ-12), and patient satisfaction tools were used to assess subjects at baseline, and at 2 and 6 weeks, and 3, 6 and 12 months post surgery. The significance of symptom score changes at 6 months and 1 year were determined by the t-test for paired data. Forty-three of the 45 patients completed the 12 month study. Results The majority of the subjects had cystocele (98%) and/or rectocele (84%) defects at study entry. At 12 months, 74% of the defects had improved to a stage 0 or 1. Mean PFDI-20 scores improved by 72% (p < 0.001) at 12 months, and PISQ-12 scores were maintained during the follow-up period indicating no decline in sexual function. Three subjects experienced one serious adverse event each; one of the adverse events (constipation) was deemed by the study physician to be unrelated to Xenform®. One subject had severe pyelonephritis resulting in dialysis. This subject had a previous history of pyelonephritis, sepsis and acute renal failure. The third subject had a reported recurrent cystocele of moderate severity, possibly related to the device. No graft related erosions or pain lasting more than 30 days were reported. No subjects withdrew due to an adverse event. Conclusion This study is the first to investigate the use of Xenform® Matrix in vaginal reconstructive surgery among patients with POP. Significant improvement was maintained at 12 months utilizing both objective and subjective assessment tools, confirming the safety and efficacy of this material in vaginal surgery. Trial Registration ClinicalTrials.gov NCT01244165 PMID:21144043

  3. Reduction of SeO{sub 4}{sup 2{minus}} anions and anoxic formation of iron(II)-Iron(III) hydroxy-selenate green rust

    SciTech Connect

    Refait, P.; Simon, L.; Genin, J.M.R.

    2000-03-01

    Iron(II)-iron(III) hydroxy-salts known as green rusts were recently discovered as minerals present in hydromorphic soils and sediments. Due to their high reactivity, they are envisioned as potential reducing agents of a number of pollutants such as nitrate, chromate, or selenate. The interaction of selenate ions with such iron(II)-containing hydroxy compounds was studied by monitoring the oxidation processes of the iron phases with transmission Moessbauer spectroscopy measured at 14 K and by following the evolution of Se(VI) in solution by capillary electrophoresis. This interaction involved the hydroxy-selenate green rust, a compound isomorphous to the hydroxy-sulfate GR(SO{sub 4}{sup 2{minus}}). Its chemical composition, Fe{sub y}{sup II}Fe{sub 2}{sup III}(OH){sub 2(y+2)}SeO{sub 4}{center_dot}8H{sub 2}O, varied with time since y starts at 5.5 and ends at 4. GR(SeO{sub 4}{sup 2{minus}}) was obtained from Fe(OH){sub 2} precipitates by simultaneous accumulation of SeO{sub 4}{sup 2{minus}} anions inside the solid phase and reduction of an equal amount of SeO{sub 4}{sup 2{minus}} anions to Se(IV) species. These species were found to be less mobile, partially bound to iron compounds and/or forming iron salts. Finally, the hydroxy-selenate GR2(SeO{sub 4}{sup 2{minus}}) can form without any other oxidizing agent than selenate itself.

  4. Mineralogical characterization of arsenic in gold mine tailings from three sites in Nova Scotia

    SciTech Connect

    M Corriveau; H Jamieson; M Parsons; G Hall

    2011-12-31

    Chronic exposure to high concentrations of arsenic (As) in windblown and vehicle-raised dust from tailings sites in Nova Scotia poses a potential health risk to recreational users of these areas and to nearby residents. The exposure may involve inhalation of dust, as well as oral ingestion of particles. It is important to understand the mineralogy and morphology of As-bearing dust particles in order to evaluate the risk posed by near-surface particulates in As-bearing tailings fields, as this will influence the stability and toxicity of As in the wastes. Optical mineralogy, scanning electron microscopy, electron microprobe, X-ray diffraction, synchrotron-based micro-X-ray diffraction ({mu}XRD) and micro-X-ray absorption near edge structure ({mu}XANES), and sequential leach extractions were applied to tailings samples from three sites in eastern Nova Scotia. Arsenic occurs naturally in these gold deposits mainly in arsenopyrite (FeAsS). In the near-surface material of the tailings fields, sulphide minerals have almost completely oxidized to secondary minerals such as scorodite (FeAsO{sub 4}{center_dot}2H{sub 2}O) and Ca-Fe arsenates. Iron oxyhydroxides contain variable amounts of As{sub 2}O{sub 5} from trace to 30 wt.% and CaO up to 8 wt.%. The presence of multiple As-hosting solid phases, including relatively soluble Ca-Fe arsenates and Fe oxyhydroxides with adsorbed As has important implications for human health risk assessment and remediation design.

  5. Polymyalgia Rheumatica (PMR) Special Interest Group at OMERACT 11: outcomes of importance for patients with PMR.

    PubMed

    Mackie, Sarah L; Arat, Seher; da Silva, Jose; Duarte, Catia; Halliday, Sue; Hughes, Rod; Morris, Marianne; Pease, Colin T; Sherman, Jeffrey W; Simon, Lee S; Walsh, Maggie; Westhovens, René; Zakout, Samy; Kirwan, John R

    2014-04-01

    We worked toward developing a core outcome set for clinical research studies in polymyalgia rheumatica (PMR) by conducting (1) patient consultations using modified nominal group technique; (2) a systematic literature review of outcome measures in PMR; (3) a pilot observational study of patients presenting with untreated PMR, and further discussion with patient research partners; and (4) a qualitative focus group study of patients with PMR on the meaning of stiffness, using thematic analysis. (1) Consultations included 104 patients at 4 centers. Symptoms of PMR included pain, stiffness, fatigue, and sleep disturbance. Function, anxiety, and depression were also often mentioned. Participants expressed concerns about diagnostic delay, adverse effects of glucocorticoids, and fear of relapse. (2) In the systematic review, outcome measures previously used for PMR include pain visual analog scores (VAS), morning stiffness, blood markers, function, and quality of life; standardized effect sizes posttreatment were large. (3) Findings from the observational study indicated that asking about symptom severity at 7 AM, or "on waking," appeared more relevant to disease activity than asking about symptom severity "now" (which depended on the time of assessment). (4) Preliminary results were presented from the focus group qualitative study, encompassing broad themes of stiffness, pain, and the effect of PMR on patients' lives. It was concluded that further validation work is required before a core outcome set in PMR can be recommended. Nevertheless, the large standardized effect sizes suggest that pain VAS is likely to be satisfactory as a primary outcome measure for assessing response to initial therapy of PMR. Dissection of between-patient heterogeneity in the subsequent treatment course may require attention to comorbidity as a potential confounding factor.

  6. Structure of Calcium Aluminate Decahydrate (CaAl2O4.10D2O) from Neutron and X-ray Powder Diffraction Data

    SciTech Connect

    Christensen,A.; Lebech, B.; Sheptyakov, D.; Hanson, J.

    2007-01-01

    Calcium aluminate decahydrate is hexagonal with the space group P63/m and Z = 6. The compound has been named CaAl2O4{center_dot}10H2O (CAH10) for decades and is known as the product obtained by hydration of CaAl2O4 (CA) in the temperature region 273-288 K - one of the main components in high-alumina cements. The lattice constants depend on the water content. Several sample preparations were used in this investigation: one CAH10, three CAD10 and one CA(D/H)10, where the latter is a zero-matrix sample showing no coherent scattering contribution from the D/H atoms in a neutron diffraction powder pattern. The crystal structure including the positions of the H/D atoms was determined from analyses of four neutron diffraction powder patterns by means of the ab initio crystal structure determination program FOX and the FULLPROF crystal structure refinement program. Additionally, eight X-ray powder diffraction patterns (Cu K[alpha]1 and synchrotron X-rays) were used to establish phase purity. The analyses of these combined neutron and X-ray diffraction data clearly show that the previously published positions of the O atoms in the water molecules are in error. Thermogravimetric analysis of the CAD10 sample preparation used for the neutron diffraction studies gave the composition CaAl2(OD)8(D2O)2{center_dot}2.42D2O. Neutron and X-ray powder diffraction data gave the structural formula CaAl2(OX)8(X2O)2{center_dot}[gamma]X2O (X = D, H and D/H), where the [gamma] values are sample dependent and lie between 2.3 and 3.3.

  7. Impact of Age-related Macular Degeneration on Vision-Specific Quality of Life: Follow-Up from the 10-Year and 15-Year Visits of The Study of Osteoporotic Fractures

    PubMed Central

    Coleman, Anne L.; Yu, Fei; Ensrud, Kristine E.; Stone, Katie L.; Cauley, Jane A; Pedula, Kathryn L.; Hochberg, Marc C.; Mangione, Carol M.

    2010-01-01

    Purpose To assess vision-specific quality of life (QOL), based on abbreviated surveys derived from the National Eye Institute Visual Function Questionnaire (NEI-VFQ), in a cohort of US women who participated in the Study of Osteoporotic Fractures (SOF). Design Prospective, observational cohort study Methods Age-related macular degeneration (AMD) status, based on a three level classification (no AMD, early AMD, late AMD), and vision-specific QOL, based on abbreviated NEI-VFQ surveys were calculated for 1,674 women enrolled in the SOF at 4 centers within the US, who had gradable fundus photographs at both the 10-year and 15-year follow-up visits. The associations among 5-year changes in NEI-VFQ composite scores, change in AMD status, and distance visual acuity were examined. Results Compared to study participants without AMD at both visits, study participants with late AMD at both visits and those that progressed from early AMD to late AMD demonstrated the greatest declines in adjusted NEI-VFQ composite scores, up to a mean decrease of 16.2 out of a scale of 100. Visual acuity declines were also most prominent for patients with late AMD at both visits and for those that progressed from early AMD to late AMD. Change in visual acuity was found to correlate significantly with change in vision-specific QOL. Conclusions The abbreviated NEI-VFQ surveys provide reliable assessments of vision-specific QOL in AMD patients. The decline in vision-specific QOL associated with the progression of AMD is clinically meaningful. PMID:20691423

  8. Rare-earth-free red-emitting K2Ge4O9:Mn(4+) phosphor excited by blue light for warm white LEDs.

    PubMed

    Ding, Xin; Wang, Qian; Wang, Yuhua

    2016-03-21

    A series of novel K2Ge4O9:Mn(4+) phosphors with red emission under blue light excitation have been synthesized successfully by traditional high-temperature solid-state reaction. The structure of K2Ge4O9 has been investigated by high-resolution transmission electron microscopy, scanning electron microscopy and X-ray powder diffraction with Rietveld refinement. The PL properties have been investigated by measuring diffuse reflection spectra, emission spectra, excitation spectra, decay curves and temperature-dependent spectra. The KGO:0.1% Mn(4+) phosphor can emit red light peaking at 663 nm under UV or blue light excitation. The critical quenching concentration of Mn(4+) was about 0.1 mol%. The concentration quenching mechanism could be a d-d interaction for the Mn(4+) center. The CIE chromaticity coordinates and FWHM are (0.702, 0.296) and 20 nm, which demonstrated that the K2Ge4O9:Mn(4+) has a high color purity. By tuning the weight ratio of yellow and red phosphors, the fabricated white LEDs, using a 455 nm InGaN blue chip combined with a blend of the yellow phosphor YAG:Ce(3+) and the red-emitting KGO:Mn(4+) phosphor driven by a 40 mA current, can get white light with chromaticity coordinates (0.405, 0.356) and CCT 3119 K. These results indicated that K2Ge4O9:Mn(4+) is a potential red phosphor to match blue LED chips to get warm white light.

  9. Synthesis and characterization of thorium(IV) sulfates.

    PubMed

    Knope, Karah E; Wilson, Richard E; Skanthakumar, S; Soderholm, L

    2011-09-05

    Three Th(IV) sulfates, two new and one previously reported, have been synthesized from aqueous solution. In all of the compounds, the sulfate anions coordinate the Th(4+) metal center(s) in a monodentate manner with Th-S distances of 3.7-3.8 Å. Th(SO(4))(2)(H(2)O)(7)·2(H(2)O) (1; P2(1)/m, a = 7.224(1) Å, b = 12.151(1) Å, c = 7.989(1) Å, ss =98.289(2)°) and Th(4)(SO(4))(7)(H(2)O)(7)(OH)(2)·H(2)O (2; Pnma, a = 18.139(2) Å, b = 11.173(1) Å, c = 14.391(2) Å) each contain 9-coordinate monomeric (1,2) and dimeric (2) Th(IV) cations in monocapped square antiprism geometry. Alternatively, Th(OH)(2)SO(4) (3; Pnma, a = 11.684(1) Å, b = 6.047(1) Å, c = 7.047(1) Å) is built from chains of hydroxo-bridged, 8-coordinate Th(4+) centers. Whereas 1 adopts a molecular structure, 2 and 3 both exhibit 3D architectures. Differences in the dimensionality and the topology of 1-3 are manifested in the local coordination environment about the Th(IV) centers, the formation of oligomeric Th(4+) species, and the extended connectivity of the sulfate ligands. Herein, we report the syntheses and characterization of 1-3 as well as the atomic correlations of 1 in solution, as determined by high-energy X-ray scattering (HEXS).

  10. The use of FBC wastes in the reclamation of coal slurry solids

    SciTech Connect

    Dreher, G.B.

    1991-01-01

    Fluidized bed combustion (FBC) is a relatively new technology that is used commercially for the combustion of coal. In Illinois, this technology is valuable because it allows the combustion of Illinois high sulfur coal without pollution of the atmosphere with vast quantities of sulfur oxides. In FBC, coal is mixed with limestone or dolomite either before injection into the combustion chamber or in the combustion chamber. As the coal burns, sulfur in the coal is oxidized to SO{sub 2} and this is trapped by reaction with the limestone or dolomite to form gypsum (CaSO{sub 4}{center dot}2H{sub 2}O). Solid by-products from FBC are generally a mixture of calcium oxide, gypsum, coal ash, and unburned coal. The present research project is designed to provide initial data on one possible use of FBC waste. FBC wastes from five different locations in the Illinois are mixed with coal slurry solids from two different coal preparation plants at Illinois coal mines. In mixtures of FBC waste and coal slurry solids, the alkaline components of the FBC waste are expected to react with acid produced by the oxidation of pyrite in the coal slurry solid. An objective of this research is to determine the chemical composition of aqueous leachates from mixtures of FBC wastes, generated under various operating conditions, and the coal slurry solids. These data will be used in future research into the ability of such mixtures to support seed germination and plant growth. The ultimate of this and future research is to determine whether mixed FBC waste and coal slurry solids can be slurry pond reclamation.

  11. The use of FBC wastes in the reclamation of coal slurry solids. Technical report, September 1--November 30, 1991

    SciTech Connect

    Dreher, G.B.

    1991-12-31

    Fluidized bed combustion (FBC) is a relatively new technology that is used commercially for the combustion of coal. In Illinois, this technology is valuable because it allows the combustion of Illinois high sulfur coal without pollution of the atmosphere with vast quantities of sulfur oxides. In FBC, coal is mixed with limestone or dolomite either before injection into the combustion chamber or in the combustion chamber. As the coal burns, sulfur in the coal is oxidized to SO{sub 2} and this is trapped by reaction with the limestone or dolomite to form gypsum (CaSO{sub 4}{center_dot}2H{sub 2}O). Solid by-products from FBC are generally a mixture of calcium oxide, gypsum, coal ash, and unburned coal. The present research project is designed to provide initial data on one possible use of FBC waste. FBC wastes from five different locations in the Illinois are mixed with coal slurry solids from two different coal preparation plants at Illinois coal mines. In mixtures of FBC waste and coal slurry solids, the alkaline components of the FBC waste are expected to react with acid produced by the oxidation of pyrite in the coal slurry solid. An objective of this research is to determine the chemical composition of aqueous leachates from mixtures of FBC wastes, generated under various operating conditions, and the coal slurry solids. These data will be used in future research into the ability of such mixtures to support seed germination and plant growth. The ultimate of this and future research is to determine whether mixed FBC waste and coal slurry solids can be slurry pond reclamation.

  12. Novel alkaline earth copper germanates with ferro and antiferromagnetic S=1/2 chains

    SciTech Connect

    Brandao, Paula; Reis, Mario S; Gai, Zheng; Moreira Dos Santos, Antonio F

    2013-01-01

    Two new alkaline earth copper(II) germanates were hydrothermally synthesized: CaCuGeO4 center dot H2O (1) and BaCu2Ge3O9 center dot H2O (2), and their structures determined by single crystal X-ray diffraction. Compound (1) crystallizes in space group P2(1)/c with a=5.1320(2) angstrom, b=16.1637(5) angstrom, c=5.4818(2) angstrom, beta=102.609(2)degrees, V=443.76(3) angstrom(3) and Z=4. This copper germanate contains layers of composition [CuGeO4](infinity)(2-) comprising CuO4 square planes and GeO4 tetrahedra with calcium and water molecules in the inter-layer space. Compound (2) crystallizes in the Cmcm space group with a=5.5593(3) angstrom, b=10.8606(9) angstrom, c=13.5409(8) angstrom, V=817.56(9) angstrom(3) and Z=4. This structure contains GeO6 and CuO6 octahedra as well as GeO4 tetrahedra, forming a three-dimensional network of interconnecting six-membered ring channels. The magnetic susceptibility for both samples can be interpreted as S=1/2 chains, in agreement with the copper topology observed in the crystal structure. The susceptibility of (1) exhibits a Bonner-Fisher type behavior, resulting from antiferromagnetic intra-chain interactions without three-dimensional ordering down to 5 K-the lowest measured temperature. This observation, together with the absence of super-exchange paths between the copper chains, make this system particularly promising for the study of low dimensional magnetism. The magnetic properties of (2) show a very weak ferromagnetic near-neighbor interaction along the chain. In this compound a peak the chi T plot seems to indicate the onset of interchain antiferromagentic correlations. However, no ordering temperature is detected in the susceptibility data.

  13. First examples of hybrids based on polyoxometalates, metal halide clusters and organic ligands

    SciTech Connect

    Wang Lamei; Fan Yong; Wang Yan; Xiao Lina; Hu Yangyang; Peng Yu; Wang Tiegang; Gao Zhongmin; Zheng Dafang; Cui Xiaobing; Xu Jiqing

    2012-07-15

    Two new organic-inorganic compounds based on polyoxometalates, metal halide clusters and organic ligands: [BW{sub 12}O{sub 40}]{sub 2}[Cu{sub 2}(Phen){sub 4}Cl](H{sub 2}4, 4 Prime -bpy){sub 4}{center_dot}H{sub 3}O{center_dot}5H{sub 2}O (1) and [HPW{sub 12}O{sub 40}][Cd{sub 2}(Phen){sub 4}Cl{sub 2}](4, 4 Prime -bpy) (2) (Phen=1, 10-phenanthroline, bpy=bipyridine), have been prepared and characterized by IR, UV-vis, XPS, XRD and single crystal X-ray diffraction analyses. Crystal structure analyses reveal that compound 1 is constructed from [BW{sub 12}O{sub 40}]{sup 5-}, metal halide clusters [Cu{sub 2}(Phen){sub 4}Cl]{sup +}and 4, 4 Prime -bpy ligands, while compound 2 is constructed from [PW{sub 12}O{sub 40}]{sup 3-}, metal halide cluster [Cd{sub 2}(Phen){sub 4}Cl{sub 2}]{sup 2+} and 4, 4 Prime -bpy ligands. Compound 1 and compound 2 are not common hybrids based on polyoxometalates and metal halide clusters, they also contain dissociated organic ligands, therefore, compound 1 and 2 are the first examples of hybrids based on polyoxometalates, metal halide clusters and organic ligands. - Graphical Abstract: Two new compounds have been synthesized and characterized. Structure analyses revealed that the two compounds are the first examples of hybrids based on polyoxometalates, metal halide clusters and organic ligands. Highlights: Black-Right-Pointing-Pointer First examples of hybrids based on polyoxometalates, metal halide clusters and organic ligands. Black-Right-Pointing-Pointer Two different kinds of metal halide clusters. Black-Right-Pointing-Pointer Supramolecular structures based on polyoxometalates, metal halide clusters and organic ligands. Black-Right-Pointing-Pointer Hybridization of three different of building blocks.

  14. High Resolution Imaging of Io's Volcanoes with LBTI

    NASA Astrophysics Data System (ADS)

    Conrad, Al; Leisenring, Jarron; de Kleer, Katherine; Skemer, Andy; Hinz, Philip; Skrutskie, Michael; Veillet, Christian; de Pater, Imke; Bertero, Mario; Boccacci, Patrizia; Defrère, Denis; Hofmann, Karl-Heinz; La Camera, Andrea; Schertl, Dieter; Spencer, John; Weigelt, Gerd; Woodward, Charles E.

    2014-11-01

    The Large Binocular Telescope (LBT), located on Mount Graham in eastern Arizona, employs two 8.4 meter mirrors with a 14.4 center-to-center separation on a common mount. Coherent combination of these two AO-corrected apertures via the LBT Interferometer (LBTI) produces Fizeau interferometric images with spatial resolution consistent with the diffraction limit of the 22.8-meter aperture. In particular LBTI resolves thermal signatures (i.e., features observed at M-band) on the surface of Io down to ~150 kilometers; a two-fold improvement over what has previously been possible from the ground. We show images collected with LBTI on December 24, 2013, in which Loki's shape is clearly resolved and at least fourteen additional volcanic hot spots are detected.We analyze three locations in the LBTI data: emission features within Loki Patera, the area near Rarog and Heno Patarae, and a hot spot seen in the Colchis Regio.For Loki Patera, we interpret spatially resolved variation in the emission within that region. With M-band resolution that is comparable to what has previously been achievable only at K-band, we compare localized emission features with what has been seen in earlier observations at shorter wavelengths.Thermal emission from activity at Rarog and Heno Patarae is well resolved in these images, while a third hot-spot in the nearby Lerna Regio is also clearly resolved. This area is of special interest since it was the site of two high-effusion outbursts on August 15th, 2013 [de Pater et al. (2014) Icarus].Lastly, we explore a hot-spot seen in the Colchis Regio that may be a remnant of a violent outburst detected on August 29th, 2013 [de Kleer et al. (2014) Icarus].

  15. Two new metal-organic coordination polymers of lead with O-, N-donor ligands: Synthesis, characterization, luminescence and thermal behavior

    SciTech Connect

    Rana, Abhinandan; Kumar Jana, Swapan; Bera, Madhusudan; Hazari, Debdoot; Sankar Chowdhuri, Durga; Zangrando, Ennio; Dalai, Sudipta

    2013-01-15

    The synthesis of two new lead(II) coordination polymers, [Pb{sub 2}(picOH){sub 4}]{center_dot}H{sub 2}O (1) and [Pb{sub 3}(Sip){sub 2}(H{sub 2}O){sub 2}]{center_dot}H{sub 2}O (2) has been reported, where HpicOH=3-hydroxypicolinic acid and NaH{sub 2}Sip=5-sulfoisophthalic acid monosodium salt. Both the complexes were structurally characterized by X-ray single crystal diffraction analysis. Complex 1, where the 3-hydroxypicolinate ligand is used for the first time in conjunction with Pb(II), revealed to be a 1D polymeric array. Complex 2 showed a 3D structure with 5-sulfoisophthalate ligand adopting two novel binding modes of high denticity ({eta}{sup 6}{mu}{sub 6} and {eta}{sup 7}{mu}{sub 7}). The photoluminescence and thermal properties of the two complexes have been studied. - Graphical abstract: 1D and 3D inorganic organic hybrid luminescent material of Pb(II) have been synthesized by using 3-hydroxypicolinate and 5-sulfoisophthalate anions. The 5-sulfoisophthalate ligand shows two novel binding modes with high denticity. Highlights: Black-Right-Pointing-Pointer 3-hydroxypicolinic acid is used for first time with Pb{sup 2+} in a MOF. Black-Right-Pointing-Pointer 5-sulfoisophthalic acid displays two novel binding modes of high denticity. Black-Right-Pointing-Pointer Complex 1 shows high thermal stability (up to 167 Degree-Sign C). Black-Right-Pointing-Pointer MLCT is present in both the complexes.

  16. Prospective, multicenter evaluation of balloon sinus dilation for treatment of pediatric chronic rhinosinusitis

    PubMed Central

    Rosenbloom, Jeffrey S.; Skarada, Douglas; Gutman, Michael; Hoy, Mark J.; Nguyen, Shaun A.

    2016-01-01

    Background Although balloon sinus dilation is a treatment option for adults with chronic rhinosinusitis (CRS), there have been few studies performed in pediatric patients. Methods This study was designed as a prospective, multicenter, single‐arm investigation. Children (2 to 21 years old) with CRS who had failed medical management were treated with balloon sinus dilation and followed to 6 months postprocedure. Results Fifty children were treated at 4 centers; 33 participants were 2 to 12 years old (mean ± standard deviation age: 6.6 ± 2.2 years) and 17 participants were >12 to 21 years (mean age: 15.7 ± 2.5 years). A total of 157 sinus dilations were attempted (98 maxillary, 30 frontal, and 29 sphenoid sinuses) and all were successful with no complications. Significant improvement in the Sinus and Nasal Quality of Life Survey (SN‐5) was seen for all children between baseline and 6 months (4.6 ± 1.2 vs 1.7 ± 0.8; p < 0.0001) and 92% improved by a minimal clinically important difference (MCID) of 1.0 or more. Those children aged 2 to 12 years with standalone balloon dilation also showed significant SN‐5 improvements between baseline and follow‐up (4.5 ± 1.0 vs 1.9 ± 0.8; p < 0.0001). Multivariate regression analysis showed no differences or associations of SN‐5 improvement at 6 months with the presence of allergy, asthma, or concomitant procedures. For adolescents, overall 22‐item Sino‐Nasal Outcome Test (SNOT‐22) mean scores were also significantly improved at 6 months (42.2 ± 19.2 vs 10.4 ± 9.7; p < 0.0001). Conclusion Balloon sinus dilation is safe and appears effective for children with CRS aged 2 years and older. PMID:27888649

  17. Factors affecting expanded electricity trade in North America

    SciTech Connect

    Hill, L.J.

    1994-01-01

    The authors explore factors that affect electricity trade between enterprises in the US and Canada and the US and Mexico. They look to those underlying policy and institutional factors that affect the relative costs of producing electricity in the three countries. In particular, they consider six factors that appear to have a significant impact on electricity trade in North America: differences in the types of economic regulation of power leading to differences in cost recovery for wholesale and retail power and wheeling charges; changing regulatory attitudes, placing more emphasis on demand-side management and environmental concerns; differences in energy and economic policies; differences in national and subnational environmental policies; changing organization of electric power industries which may foster uncertainty, change historical relationships, and provide other potentially important sources of power for distribution utilities; and differences in the ability of enterprises to gain access to electric power markets because of restrictions placed on transmission access. In Section 2, the authors discuss the regulation of electricity trade in North America and provide an overview of the recent trading experience for electricity between Canada and the US and between Mexico and the US, including the volume of that trade over the past decade and existing transmission capacity between regions of the three countries. In Section 3, they look at the benefits that accrue to trading counties and what those benefits are likely to be for the three countries. The discussion in Section 4 centers on the relevant provisions of the Canada Free Trade Agreement and the proposed North American Free Trade Agreement. In Section 5, they set the stage for the discussion of policy and institutional differences presented in Section 6 by outlining differences in the organization of the electric power sectors of Canada, the US, and Mexico. The study is synthesized in Section 7.

  18. Long term follow-up study to evaluate immunogenicity and safety of a single dose of live attenuated hepatitis a vaccine in children.

    PubMed

    Mitra, Monjori; Shah, Nitin; Faridi, Mma; Ghosh, Apurba; Sankaranarayanan, V S; Aggarwal, Anju; Chatterjee, Suparna; Bhattacharyya, Nisha; Kadhe, Ganesh; Vishnoi, Gaurav; Mane, Amey

    2015-01-01

    Worldwide, viral hepatitis continues to be a cause of considerable morbidity and mortality. Mass immunization with a single dose of live attenuated HAV has been shown to significantly reduce disease burden in the community. This was a phase IV, 5-year follow up study carried out at 4 centers (Kolkata, Delhi, Mumbai and Chennai) across India. The subjects with antibody titer <20 mIU/mL at baseline were evaluated for long term immunogenicity. Of the 503 subjects enrolled, 349 subjects were baseline seronegative with an anti-HAV antibody titer <20 mIU/mL. Overall, 343 subjects could be followed up at some point of time during this 5 y post vaccination period. In the last year (60 months) of follow-up, 108 subjects (97.3%) of 111 subjects (who came for follow-up at the end of 5 y) had a protective antibody titer (anti-HAV antibody titer >20 mIU/mL). The seroconversion rates considering seroprotection levels of anti-HAV antibody titer >20 mIU/mL, following vaccination starting from 6 weeks, 6 months, 12 months, 24 months, 36 months, 48 months and 60 months were 95.1%, 97.9%, 98.3%, 96.2%, 97.8%, 92.6% and 97.3%, respectively. The geometric mean concentration (GMC) over the years increased from 64.9 mIU/mL at 6 weeks to 38.1 mIU/mL and 135.2 mIU/mL at 6 months and 12 months, respectively and was maintained at 127.1 mIU/mL at 60 months. In conclusion, the result of this 5-year follow up study showed that the single dose of live attenuated vaccine is well tolerated and provides long-term immunogenicity in healthy Indian children.

  19. IR laser power transmission through silver halide crystals and polycrystalline fibers

    SciTech Connect

    Nagli, L.; Burstein, D.; Shalem, S.; German, A.

    1997-12-01

    Laser-induced breakdown (LIB) thresholds in AgC{sub x},Br{sub 1-x} crystals and fibers were studied under CO{sub 2} laser pulsed and CW excitation. The value of LIB threshold P{sub c} of the bulk crystals is about 7.2{center_dot}10{sup 8} W/cm{sup 2} for AgCl and 4{center_dot}10{sup 9} W/cm{sup 2} for AgBr under 60 ns TEA laser excitation. The LIB threshold in fibers is much smaller; about 2{center_dot}10{sup 8} W/cm{sup 2}. The absorption of the crystals at 10.6 {mu}m changes from 8{center_dot}10{sup -5} cm{sup -1} for AgCl to 2{center_dot}10{sup -5 }cm{sup -1} for AgBr; for fibers with the same composition absorption is much greater (3{center_dot}10{sup -4 }cm{sup -1} for AgCl; 2{center_dot}10{sup -4} cm{sup -1} for AgBr). The dependence of the LIB and IR absorption on composition, and mechanical and temperature treatments suggests that the LIB in silver halide crystals and fibers is due to the avalanche electrons in a high electric field. The initial free electrons for this process are supplied by ionization of the cation vacancy - charged dislocation complexes. The relatively lower optical stability of the fibers is due to the increased concentration of defects formed in the hot extrusion of the crystal. A simple thermal annealing method for reduction of the IR absorption is proposed.

  20. Some aspects of the atmospheric corrosion of copper in the presence of sodium chloride

    SciTech Connect

    Strandberg, H.; Johansson, L.G.

    1998-04-01

    The effect of NaCl in combination with O{sub 3} and SO{sub 2} on the atmospheric corrosion of copper was investigated. Corrosion products formed after 4 weeks exposure were characterized qualitatively by X-ray diffraction and quantitatively by gravimetry and ion chromatography of leaching solutions. Studies of SO{sub 2} deposition and O{sub 3} consumption were performed using on-line gas analysis. Large amounts of cuprite (Cu{sub 2}O) formed in all environments at 70 and 90% relative humidity. The corrosive effect of salt was strong in pure humid air and in air containing O{sub 3} or SO{sub 2}. Corrosion rate was correlated to the amount of chloride applied to the surface and to humidity. In an atmosphere containing a combination of SO{sub 2} and O{sub 3} at 90% relative humidity, corrosion was rapid in the absence of NaCl. In this case, small additions of NaCl resulted in a marked decrease in corrosion rate. In the absence of SO{sub 2}, tenorite (CuO), nantokite (CuCl), clinoatacamite [Cu{sub 2}(OH){sub 3}Cl], and malachite [Cu{sub 2}(OH){sub 2}CO{sub 3}] were identified. In the presence of SO{sub 2}, brochantite [Cu{sub 4}(OH){sub 6}SO{sub 4}], soluble sulfate, and an unknown phase occurred, while no tenorite or malachite was formed. The combination of SO{sub 2} and O{sub 3} resulted in the formation of antlerite [Cu{sub 3}(OH){sub 4}SO{sub 4}] and Cu{sub 2.5}(OH){sub 3}SO{sub 4}{center_dot}2H{sub 2}O as well.

  1. EPR evidence for magnetic exchange through a four-carbon aliphatic bridge in a binuclear copper(II) complex. Single crystal x-ray structure of 7,7'-(1,4-butanediyl)-bis(2,12-dimethyl-3,7,11,17-tetraazabicyclo(11. 3. 1)heptadeca-1(17),2,11,13,15-pentaene)nickel(II)) perchlorate monohydrate

    SciTech Connect

    Foster, K.A.; Brown, D.R.; Timken, M.D.; Van Derveer, D.G.; Belford, R.L.; Barefield, E.K.

    1988-12-01

    The single crystal x-ray structure of the title, binuclear nickel(II) complex has been determined and the compound used as a host for EPR investigations of the analogous copper(II) complex. The impetus for this work was an earlier suggestion that magnetic exchange interactions detected by EPR spectroscopy on frozen solutions of the biscopper(II) complex were a result of a direct copper-copper interaction in a closed conformation of the binuclear species. Results reported here suggest that the complex exists in the open conformation where the distance between metal centres is maximized and that the magnetic exchange occurs by a super-exchange mechanism through the aliphatic chain. The /vert bar/J/vert bar/ value for the exchange interaction is greater than 0.018 cm/sup /minus/1/. Crystal data for (Ni/sub 2/C/sub 34/H/sub 50/N/sub 8/)(ClO/sub 4/)/sub 4/ /center dot/ H/sub 2/O (298 K): monoclinic, space group P2/sub 1//n, a = 13.560(3), b = 11.678(2), c = 15.377(3) /angstrom/, /beta/ = = 108.48(2)/degree/, /rho//sub calcd/ = 1.588 g cm/sup /minus/3/ for Z = 2 and M/sub r/ = 1104.1, R = 0.068, R/sub w/ = 0.76. The intramolecular Ni-Ni distance is 9.13 /angstrom/. The analogous copper complex is isomorphorus with the nickel complex.

  2. In-situ contact electrical resistance technique for investigating corrosion inhibitor adsorption on copper electrodes

    SciTech Connect

    Moretti, G.; Quartarone, G.; Zingales, A.; Molokanov, V.V.

    1998-02-01

    Traditional electrochemical tests and the contact electrical resistance technique (CER) were used to investigate the effect on corrosion of pure copper (99.999 wt%) of adding benzotriazole (BTA) and 1-hydroxybenzotriazone (1-OH-BTA) to acidic solutions (sulfuric acid [H{sub 2}SO{sub 4}], pH = 1.7, and sodium sulfate [Na{sub 2}SO{sub 4}] until total sulfate [SO{sub 4}{sup 2{minus}}] concentration = 0.1 M). This technique permitted growth of oxide and/or salt films as well as adsorption of the organic inhibitors on the copper surface to be evaluated. Formation of copper oxide ([Cu{sub 2}O]{sub 2})., sulfate (CuSo{sub 4}{center_dot}5H{sub 2}O), thiocyanate (CuSCN), and halogenyde (CuI, CuBr, and CuCl) films on copper electrodes was followed in situ in sulfate solutions at various pH values under low overpotentials. Effects of pH, solution anion content, and/or the amount of BTA or 1-OH-BTA on electrical resistance (R) of the surface films formed on pure copper electrodes were treated. BTA acted as a more efficient corrosion inhibitor than 1-OH-BTA, reaching inhibition percentages (IP) of {approximately}90% compared to those of 1-OH-BTA, which reached a maximum of {approximately}76% in 2 {times} 10{sup {minus}3} M solutions. It was possible to distinguish between maximum R of the surface film, found in solutions containing BTA, associated with the adsorption of neutral inhibitor molecules, and the sharp rise in R attributable to [Cu(BTA)]{sub n} complex formation.

  3. Densitometer-Specific Differences in the Correlation Between Body Mass Index and Lumbar Spine Trabecular Bone Score.

    PubMed

    Mazzetti, Gillian; Berger, Claudie; Leslie, William D; Hans, Didier; Langsetmo, Lisa; Hanley, David A; Kovacs, Christopher S; Prior, Jerrilyn C; Kaiser, Stephanie M; Davison, K Shawn; Josse, Robert; Papaioannou, Alexandra; Adachi, Jonathan R; Goltzman, David; Morin, Suzanne N

    2016-12-26

    Trabecular bone score (TBS) is a gray-level texture measure derived from lumbar spine dual-energy X-ray absorptiometry (DXA) images that predicts fractures independent of bone mineral density (BMD). Increased abdominal soft tissue in individuals with elevated body mass index (BMI) absorbs more X-rays during image acquisition for BMD measurement and must be accommodated by the TBS algorithm. We aimed to determine if the relationship between BMI and TBS varied between 2 major manufacturers' densitometers, because different densitometers accommodate soft tissues differently. We identified 1919 women and 811 men, participants of the Canadian Multicentre Osteoporosis Study, aged ≥40 yr with lumbar spine DXA scans acquired on GE Lunar (4 centers) or Hologic (3 centers) densitometers at year 10 of follow-up. TBS was calculated for L1-L4 (TBS iNsight® software, version 2.1). A significant negative correlation between TBS and BMI was observed when TBS measurements were performed on Hologic densitometers in men (Pearson r = -0.36, p <0.0001) and in women (Pearson r = -0.33, p <0.0001); significant correlations were not seen when TBS was measured on GE Lunar densitometers (Pearson r = 0.00 in men, Pearson r = -0.02 in women). Age-adjusted linear regression models confirmed significant interactions between BMI and densitometer manufacturer for both men and women (p < 0.0001). In contrast, comparable positive correlations were observed between BMD and BMI on both Hologic and GE Lunar densitometers in men and women. In conclusion, BMI significantly affects TBS values in men and women when measured on Hologic but not GE Lunar densitometers. This finding has implications for clinical and research applications of TBS, especially when TBS is measured sequentially on DXA densitometers from different manufacturers or when results from different machines are pooled for analysis.

  4. Transport of Impurity Ions in the Wendelstein 7-AS Stellarator Plasma

    SciTech Connect

    Burhenn, Rainer; Baldzuhn, Juergen; Beidler, Craig; Brakel, Rudolf; Ehmler, Hartmut; Giannone, Louis; Grigull, Peter; Hirsch, Matthias; Knauer, Jens; Krychowiak, Maciej; Maassberg, Henning; McCormick, Kent; Pasch, Ekkehard; Weller, Arthur; Ida, Katsumi

    2006-01-15

    The impact of global plasma parameters on impurity transport in the stellarator W7-AS was investigated by laser blow-off technique. Both, density and heating power were identified to have a strong influence on impurity confinement {tau}{sub I} {approx} n{sub e}{sup 1.2}/P{sub ECRH}{sup 0.8}. In spite of stationary conditions at lower densities, an increasing trend for accumulation was observed at plasma densities beyond 5{center_dot}1019 m-3 due to reduction of the diffusion coefficients. Up to densities of at least 9{center_dot}1019 m-3, launching of electron cyclotron resonance heating (ECRH) power of 1.2 MW is able to counteract the impurity accumulation by deterioration of the impurity confinement with heating power according to the scaling law as given above. In neutral beam injection (NBI) heated plasmas at densities higher than 1{center_dot}1020m-3, long confinement times were observed, often accompanied by loss of density control and degradation of plasma energy due to increasing radiation losses. The installation of island divertor allowed a general extension of the range of accessible densities up to 4{center_dot}1020m-3: beyond a certain power-dependent threshold density (1.5-2.1{center_dot}1020m-3), the plasma enters the High Density H-mode (HDH) regime and the impurity confinement time drops to values comparable to the energy confinement time. High density plasmas could be sustained quasi-stationary with a low level of impurity radiation. The favourable impurity behavior goes along with a reduction of the inward impurity convection in the core plasma and possible changes in the edge transport. For the characterization of the general impurity behavior in W7-AS plasmas the usual transport models for axisymmetric devices are not sufficient and additional stellarator specific processes have to be considered.

  5. Designing lead-free and stable perovskite materials for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Sun, Yiyang; Zhang, Shengbai

    A critical barrier for large-scale deployment of the current perovskite solar materials is the use of Pb to achieve high power conversion efficiency. While this appears to be a technical issue, there are more fundamental reasons behind. The current research has mainly focused on the replacement of Pb by other elements, in particular, Sn. However, in halide perovskites (i.e., I-II-VII3 composition), Sn is in its less stable 2 + state. The formation of more stable 4 + centers in the Sn(II)-based materials under ambient conditions makes the device efficiency very low. Worse, there might be no other elements across the Periodic Table that can replace Pb while maintaining the desirable properties, such as band gap. Out-of-the-box ideas are therefore called for to stimulate the research in this field. In this talk, two approaches are proposed based on state-of-the-art first-principles calculations. Through a screening of chalcogenide perovskite materials, CaTiS3, BaZrS3, CaZrSe3, and CaHfSe3 have been predicted to have suitable band gaps for making solar cells. Among these materials, BaZrS3 have been synthesized experimentally. Another proposed approach is to introduce dual anions (i.e., splitting the anion sites) that allow the composition to satisfy charge neutrality, while replacing Pb by more environmentally benign elements. One of the candidate materials is CH3NH3BiSI2, which is predicted to have band gap around 1.4 eV and high optical absorption.

  6. Performances and first experimental results of BACH, the beamline for dichroism and scattering experiments at ELETTRA

    SciTech Connect

    Zangrando, M.; Zacchigna, M.; Bondino, F.; Finazzi, M.; Pardini, T.; Plate, M.; Rochow, R.; Cocco, D.; Parmigiani, F.

    2004-05-12

    BACH, the new soft x-ray beamline for polarization dependent experiments at the Italian synchrotron radiation facility ELETTRA, has been commissioned, characterized and opened to external users. Based on two APPLE II undulators, it covers an energy range between 35 eV and 1600 eV with the control of the light polarization. The monochromator works either in high resolution or high flux mode. Resolving powers of 16000 at 50 eV, 12000 at 90 eV, more than 12000 at 400 eV, 15000 at 534 eV and 6600 at 867 eV have been achieved with the three high resolution gratings. The resolving powers of the high flux grating, which covers the 290 - 1600 eV range, have been measured reaching 7000 at 400 eV and 2200 at 867 eV. The fluxes, in the high resolution mode, range between 4{center_dot}1011 photons/s at 125 eV and 2{center_dot}1010 photons/s at about 1100 eV. Using the high flux grating with the best resolution achievable 1.7{center_dot}1011 photons/s impinge on the sample at 900 eV. Two branches are installed after the monochromator allowing the set-up of two different experimental stations. One of them, besides several facilities for surface preparation and analysis, hosts a compact inelastic soft x-ray spectrometer (ComIXS) dedicated to x-ray emission experiments exploiting the small spot (10 {mu}m in the vertical direction) on the sample. The other branch hosts a liquid helium cryostat equipped with a superconducting coil to perform absorption and transmission experiments with temperatures down to 2 K and magnetic field up to {+-}7 T.

  7. Organic oxalate as leachant and precipitant for the recovery of valuable metals from spent lithium-ion batteries

    SciTech Connect

    Sun Liang; Qiu Keqiang

    2012-08-15

    Graphical abstract: Display Omitted Highlights: Black-Right-Pointing-Pointer Vacuum pyrolysis as a pretreatment was used to separate cathode material from aluminum foils. Black-Right-Pointing-Pointer Cobalt and lithium can be leached using oxalate while cobalt can be directly precipitated as cobalt oxalate. Black-Right-Pointing-Pointer Cobalt and lithium can be separated efficiently from each other only in the oxalate leaching process. Black-Right-Pointing-Pointer High reaction efficiency of LiCoO{sub 2} was obtained with oxalate. - Abstract: Spent lithium-ion batteries containing lots of strategic resources such as cobalt and lithium are considered as an attractive secondary resource. In this work, an environmentally compatible process based on vacuum pyrolysis, oxalate leaching and precipitation is applied to recover cobalt and lithium from spent lithium-ion batteries. Oxalate is introduced as leaching reagent meanwhile as precipitant which leaches and precipitates cobalt from LiCoO{sub 2} and CoO directly as CoC{sub 2}O{sub 4}{center_dot}2H{sub 2}O with 1.0 M oxalate solution at 80 Degree-Sign C and solid/liquid ratio of 50 g L{sup -1} for 120 min. The reaction efficiency of more than 98% of LiCoO{sub 2} can be achieved and cobalt and lithium can also be separated efficiently during the hydrometallurgical process. The combined process is simple and adequate for the recovery of valuable metals from spent lithium-ion batteries.

  8. International, collaborative assessment of limitations of chromosome-specific probes (CSP) and fluorescent in situ hybridization (FISH): Analysis of expected detections in 73,000 prenatal cases

    SciTech Connect

    Evans, M.I.; Henry, G.P.; Miller, W.A.

    1994-09-01

    FISH and CSP have been proposed to reduce karyotyping need. The purpose of this study was to assess the potential efficacy of CSP-FISH using currently available probes (13, 18, 21, X, & Y) in large, prenatal diagnostic centers. Results (1990-1993) from 7 centers in 4 countries were divided by those expected to be detectable by currently available probes, and those which would be missed assuming 10% probe efficacy. 72,994 karyotypes included 699 trisomy 21`s, 352 trisomy 18`s, 136 trisomy 13`s, 358 sex chromosome aneuploidies, 70 triploidies, and 855 others (translocations, inversions, deletions, markers). Of 2,613 abnormalities, 1,745 would be detectable (66.8%). [Detroit 55.7%, Stockholm 68.3%, Boston 52.6%, Denver 61.3%, Muenster 77.0%, London 84.5%, Philadelphia 69.4%]. Centers with high proportions of referrals for ultrasound anomalies had the highest CSP-FISH positives secondary to increased T 18 & 13. We conclude: (1) 73,000 karyotypes show relatively consistent incidences of the common trisomies, sex chromosome abnormalities, and other chromosome abnormalities among the centers. (2) The proportion expected detectable by FISH-CSP technology varies from 52.6% to 84.5%, averaging 66.8%. (3) 1/3 of the karyotypic abnormalities would be missed, and therefore, replacement of complete karyotyping with FISH would have unacceptably high false-negative rates for routine evaluation. (4) FISH-CSP, while useful when positive for anomalies, is not sufficient when negative to obviate the need for a complete karyotype.

  9. Products from reactions of [Mn[sub 2]O[sub 2](O[sub 2]CCH[sub 3])(tpen)][sup 2+] in acidic and neutral aqueous media: [Mn[sub 2]([mu]-O)[sub 2]([mu]-O[sub 2]CCH[sub 3])(tpen)][sup 3+] and [[l brace]Mn[sub 3]([mu]-O)[sub 4](OH)(tpen)[r brace][sub 2]([mu]-tpen)][sup 6+

    SciTech Connect

    Pal, S.; Armstrong, W.H. )

    1992-12-23

    The mixed-valence compound [Mn[sub 2]([mu]-O)[sub 2]([mu]-O[sub 2]CCH[sub 3])(tpen)](ClO[sub 4])[sub 2][center dot]3H[sub 2]O (2[center dot]3H[sub 2]O) reacts to form [Mn[sub 2]([mu]-O)[sub 2]([mu]-O[sub 2]CCH[sub 3])(tpen)](ClO[sub 4])[sub 3] (3) is acidic aqueous solution and in contrast is converted to [[l brace]Mn[sub 3]([mu]-O)[sub 4](OH)(tpen)[r brace][sub 2]([mu]-tpen)](ClO[sub 4])[sub 6][center dot]4H[sub 2]O (4[center dot]4H[sub 2]O) in distilled water (tpen is N,N,N[prime],N[prime]-tetrakis(2-pyridylmethyl)-1,2-ethanediamine). Both reactions were carried out in the presence of a large excess of perchlorate counterion. Syntheses, structures, and selected properties of 3 and 4 are reported. Structural parameters for 3 are consistent with both manganese ions being in the 4+ oxidation state. The cyclic voltammogram of 3 in CH[sub 3]CN exhibits IV,IV/IV,III and IV,III/III,III reductions at +0.90 and [minus]0.13 V, respectively, vs SSCE. The cation in 4 resides on an inversion center. Bond distances and angles in 4 confirm that all Mn atoms are in the +4 oxidation state. The structure of 4 consists of two [l brace]Mn[sub 3]O[sub 4][r brace][sup 4+] units linked by one tpen moiety. The [l brace]Mn[sub 3]O[sub 4][r brace][sup 4+] cores in 4 are distorted in a manner that is reminiscent of [Mn[sub 3]O[sub 4](OH)(bpea)[sub 3

  10. Luminescence and creation of electron centers in UV-irradiated YAlO{sub 3} single crystals

    SciTech Connect

    Grigorjeva, L.; Krasnikov, A.; Zazubovich, S.; Laguta, V. V.; Nikl, M.

    2010-09-15

    Luminescence and defect creation processes were studied by the photoluminescence, thermally stimulated luminescence, and electron paramagnetic resonance methods in the UV-irradiated single crystals of undoped YAlO{sub 3}, containing small amounts of Ce, Mo, and Ti ions as accidental impurities. The luminescence of the electron antisite Y{sub Al}{sup 2+}-type centers of different structures was found around 2.45 eV and studied at 4.2-500 K. The luminescence of the Ti{sup 3+}-related centers (2.03 and 1.73 eV) and Ti{sup 4+} centers (2.78 eV) was observed as well. Dependences of the number of the Y{sub Al}{sup 2+}-type and Ti{sup 3+}-related centers on the UV irradiation energy, temperature, and duration, as well as on various crystal heat-treatment procedures were examined. As a result of the photostimulated electron transfer from the O{sup 2-} ligand ions to Mo{sup 4+} and Ti{sup 4+} ions, the paramagnetic hole O{sup -}-type centers and electron Ti{sup 3+} and Mo{sup 3+} centers are created. The antisite Y{sub Al}{sup 2+}-type centers are created due to the photostimulated release of electrons mainly from the Mo{sup 3+} centers to the conduction band and their subsequent trapping at the Y{sub Al}{sup 3+} ions located near an oxygen vacancy or a defect at the neighboring Y{sup 3+} site.

  11. A Randomized Study on the Effect of Weight Loss on Obstructive Sleep Apnea Among Obese Patients With Type 2 Diabetes

    PubMed Central

    Foster, Gary D.; Borradaile, Kelley E.; Sanders, Mark H.; Millman, Richard; Zammit, Gary; Newman, Anne B.; Wadden, Thomas A.; Kelley, David; Wing, Rena R.; Pi-Sunyer, F. Xavier; Reboussin, David; Kuna, Samuel T.

    2010-01-01

    Background The belief that weight loss improves obstructive sleep apnea (OSA) has limited empirical support. The purpose of this 4-center study was to assess the effects of weight loss on OSA over a 1-year period. Methods The study included 264 participants with type 2 diabetes and a mean (SD) age of 61.2 (6.5) years, weight of 102.4 (18.3) kg, body mass index (BMI) (calculated as weight in kilograms divided by height in meters squared) of 36.7 (5.7), and an apnea-hypopnea index (AHI) of 23.2 (16.5) events per hour. The participants were randomly assigned to either a behavioral weight loss program developed specifically for obese patients with type 2 diabetes (intensive lifestyle intervention [ILI]) or 3 group sessions related to effective diabetes management (diabetes support and education [DSE]). Results The ILI participants lost more weight at 1 year than did DSE participants (10.8 kg vs 0.6 kg; P < .00l). Relative to the DSE group, the ILI intervention was associated with an adjusted (SE) decrease in AHI of 9.7 (2.0) events per hour (P < .001). At 1 year, more than 3 times as many participants in the ILI group than in the DSE group had total remission of their OSA, and the prevalence of severe OSA among ILI participants was half that of the DSE group. Initial AHI and weight loss were the strongest predictors of changes in AHI at 1 year (P<.01). Participants with a weight loss of 10 kg or more had the greatest reductions in AHI. Conclusions Physicians and their patients can expect that weight loss will result in significant and clinically relevant improvements in OSA among obese patients with type 2 diabetes. Trial Registration clinicaltrials.gov Identifier: NCT00194259 PMID:19786682

  12. The use of FBC wastes in the reclamation of coal slurry solids. Technical report, March 1, 1992--May 31, 1992

    SciTech Connect

    Dreher, G.B.; Roy, W.R.; Steele, J.D.

    1992-10-01

    Fluidized bed combustion (FBC) is a relatively new technology that is used commercially for the combustion of coal. In Illinois, this technology is valuable because it allows the combustion of Illinois high sulfur coal without pollution of the atmosphere with vast quantities of sulfur oxides. In FBC, coal is mixed with limestone or dolomite either before injection into the combustion chamber or in the combustion chamber. As the coal burns, sulfur in the coal is oxidized to S0{sub 2} and this is trapped by reaction with the limestone or dolomite to form gypsum (CaSO{sub 4} {center_dot} 2H{sub 2}O). Solid by-products from FBC are generally a mixture of calcium oxide, gypsum, coal ash, and unburned coal. The present research project is designed to provide initial data on one possible use of FBC waste. FBC wastes from five different locations in Illinois are mixed with coal slurry solids (CSS) from two different coal preparation plants at Illinois coal mines. In mixtures of FBC waste and coal slurry solids, the alkaline components of the FBC waste are expected to react with acid produced by the oxidation of pyrite in the coal slurry solid. An objective of this research is to determine the chemical composition of aqueous leachates from mixtures of FBC wastes, generated under various operating conditions, and the coal slurry solids. These data will be used in future research into the ability of such mixtures to support seed germination and plant growth. The final goal of this and future research is to determine whether mixed FBC waste and coal slurry solids can be used as a satisfactory growing medium in slurry pond reclamation. The chemical analyses of the 8 starting solids (5 FBC wastes, 2 Css samples, and 1 agricultural limestone sample) were completed.

  13. Evaluation of a Combined Ultraviolet Photocatalytic Oxidation(UVPCO)/Chemisorbent Air Cleaner for Indoor Air Applications

    SciTech Connect

    Hodgson, Alfred T.; Destaillats, Hugo; Hotchi, Toshifumi; Fisk,William J.

    2007-02-01

    buildings containing typical VOC sources. The magnitude of the expected increase will depend upon a number of interrelated factors. Series of experiments were conducted to determine if the oxidizer, sodium permanganate (NaMnO{sub 4}{center_dot}H{sub 2}O), has sufficient reaction rates and capacity to counteract formaldehyde and acetaldehyde production and enable a 50 % reduction in building ventilation rate without net increases in indoor aldehyde concentrations. A commercially produced filter element and two laboratory-fabricated media beds containing NaMnO{sub 4}{center_dot}H{sub 2}O chemisorbent media were evaluated. The effectiveness of a device for removal of formaldehyde, acetaldehyde and other VOCs was determined by measurement of concentrations immediately upstream and downstream of the device. In some experiments, conversion efficiencies and byproduct generation by the UVPCO device also were determined. Six experiments were conducted with the commercial filter element installed downstream of the UVPCO reactor. Eleven experiments were conducted with a single panel media bed (30 cm by 61 cm by 2.5 cm deep) installed downstream of the UVPCO reactor; in these, the effects of temperature and air residence time on conversion efficiency were examined. Two experiments were conducted with a four-panel, folded, media bed (approximately four times the size of the single panel bed) installed downstream of the reactor. Because the commercial unit contained activated carbon as an additional component, it was effective at removing lower volatility compounds that typically have low oxidation rates in the UVPCO reactor. The filter element also met the minimum efficiency objective for formaldehyde. However, the removal of acetaldehyde was less than required. The air residence time in the single panel bed was not optimized as the removal efficiencies for both formaldehyde and acetaldehyde were strongly inversely related to the air flow rate through the device. In addition, the

  14. A comparative study of ordinary and mineralised Portland cement clinker from two different production units Part I: Composition and hydration of the clinkers

    SciTech Connect

    Emanuelson, Anna; Hansen, Staffan; Viggh, Erik

    2003-10-01

    Portland cement clinkers from two production units were investigated; Plant 1: ordinary clinker (P1) and clinker mineralised with CaF{sub 2}+CaSO{sub 4} (P1m); Plant 2: ordinary clinker (P2) and two clinkers mineralised with CaF{sub 2}+CaSO{sub 4} (P2m, low SO{sub 3} and P2m', high SO{sub 3}). The chemical composition of the clinkers was determined by X-ray fluorescence, ICP analysis, titration (free lime) and ion selective electrode measurements (F). Observed clinker parameters (LSF, SR, AR, R, wt.% MgO, F, SO{sub 3}, free lime): P1 (0.96, 2.72, 1.27, 1.04, 0.78, 0.06, 0.64, 0.71); P1m (1.03, 2.21, 1.58, 2.18, 0.87, 0.23, 1.95, 0.69); P2 (1.00, 2.66, 1.72, 0.75, 4.06, 0.20, 1.38, 1.51); P2m (1.01, 2.91, 1.96, 0.90, 3.21, 0.39, 1.72, 2.06); P2m' (0.97, 2.70, 1.84, 1.15, 3.86, 0.42, 2.48, 0.89). The qualitative and quantitative phase compositions were characterised using X-ray powder diffraction, backscattered electron imaging, X-ray microanalysis and elemental mapping, plus optical reflection microscopy. Phases observed in all clinkers were: alite, {beta}-belite, cubic aluminate, ferrite and free lime. Additional phases observed were: aphthitalite (P1, P2, P2m, P2m'), calcium langbeinite (P1m) and periclase (P2, P2m, P2m'). The clinker composition and texture differ more between the two plants, than between ordinary and mineralised clinker from the same production unit. Laboratory cements were prepared by mixing ground clinker with CaSO{sub 4}{center_dot}2H{sub 2}O. The cements were hydrated in an isothermal calorimeter at 20 deg. C (water/cement weight ratio=0.5) during 33 h. After 12 h, the laboratory cement based on P1m reached a higher level of reaction than the one based on P1. The P2m and P2m' laboratory cements had a slower reaction than the P2 cement.

  15. Manufacture of ammonium sulfate fertilizer from FGD-gypsum. Quarterly report, 1 December 1994--28 February 1995

    SciTech Connect

    Chou, M.I.M.; Rostam-Abadi, M.; Lytle, J.M.; Bruinius, J.A.; Hoeft, R.; Dewey, S.; Achorn, F.

    1995-12-31

    The overall goal of this project is to assess the technical and economic feasibility for producing feasibility-grade ammonium sulfate from gypsum produced as part of limestone flue gas desulfurization (FGD) processes. This is a cooperative effort among the ISGS, the UIUC, AlliedSignal, SE-ME, Henry Fertilizer, Illinois Power Co. (IP), and Central Illinois Public Services (CIPS). Bench-scale experiments will be conducted to obtain process engineering data for the manufacture of ammonium sulfate from FGD-gypsum and to help evaluate technical and economic feasibility of the process. Controlled greenhouse experiments will be conducted at UIUC to evaluate the chemical impact of coal-derived impurities in ammonium sulfate produced from FGD-gypsum on soil properties. A process flow sheet will be proposed and market demand for the products will be established. An engineering team at IP will provide an independent review of the economics of the process. AlliedSignal will be involved in testing and quality evaluation of ammonium sulfate samples and is interested in an agreement to market the finished product. CIPS will provide technical assistance and samples of FGD -gypsum for the project. In this quarter, with an exception of the neutron activation analysis, analyses of FGD-gypsum samples that were generated by two power stations were completed. The high quality FGD-gypsum sample produced from the Abbott power plant in Champaign, IL was 98.36% gypsum, CaSO{sub 4}{center_dot}2H{sub 2}O, and less than 0.01% calcium`` sulfite, CaSO{sub 3}. The low quality sample from CIPS`s Newton Power Plant at Jasper, Illinois, was only 7.36% of gypsum. It was 87.54% calcium sulfite. A literature search provided the information to set up a batch, bench-scale reactor system. Reactions were conducted at 70{degrees}C for a range of times which resulted in 82% conversion of calcium sulfate to ammonium sulfate.

  16. FY04 Engineering Technology Reports Technology Base

    SciTech Connect

    Sharpe, R M

    2005-01-27

    exploration of selected technology areas with high strategic potential, such as assessment of university, laboratory, and industrial partnerships. Engineering's five Centers, in partnership with the Division Leaders and Department Heads, focus and guide longer-term investments within Engineering. The Centers attract and retain top staff, develop and maintain critical core technologies, and enable programs. Through their technology-base projects, they oversee the application of known engineering approaches and techniques to scientific and technical problems. The Centers and their Directors are as follows: (1) Center for Computational Engineering: Robert M. Sharpe; (2) Center for Microtechnology and Nanotechnology: Raymond P. Mariella, Jr. (3) Center for Nondestructive Characterization: Harry E. Martz, Jr.; (4) Center for Precision Engineering: Keith Carlisle; and (5) Center for Complex Distributed Systems: Gregory J. Suski, Acting Director.

  17. NMR and computational characterization of mitomycin cross-linked to adjacent deoxyguanosines in the minor groove of the d(T-A-C-G-T-A)ter dot d(T-A-C-G-T-A) duplex

    SciTech Connect

    Norman, D.; Sastry, M.; Patel, D.J. ); Live, D. ); Lipman, R.; Tomasz, M. ); Hingerty, B.E. ); Broyde, S. )

    1990-03-20

    Two-dimensional homonuclear and heteronuclear NMR and minimized potential energy calculations have been combined to define the structure of the antitumor agent mitomycin C (MC) cross-linked to deoxyguanosines on adjacent base pairs in the d(T1-A2-C3-G4-T5-A6){center dot}d(T7-A8-C9-G10-T11-A12) duplex. The majority of the mitomycin and nucleic acid protons in the MC-X 6-mer complex have been assigned from through-bond and through-space two-dimensional proton NMR studies in aqueous solution at 5 and 20{degree}C. The C3{center dot}G10 and G4{center dot}C9 base pairs are intact at the cross-link site and stack on each other in the complex. The amino protons of G4 and G10 resonate at 9.36 and 8.87 ppm and exhibit slow exchange with solvent H{sub 2}O. The NMR experimental data establish that the mitomycin is cross-linked to the DNA through the amino groups of G4 and G10 and is positioned in the minor groove. The proton chemical shifts and NOEs establish fraying at the ends of the d(T-A-C-G-T-A) duplex, and this feature is retained on mitomycin cross-linked formation. The NMR distance constraints have been included in minimized potential energy computations on the MC-X 6-mer complex. These computations were undertaken with the nonplanar five-membered ring of mitomycin in each of two pucker orientation. The resulting low-energy structures MX1 and MX2 have the mitomycin cross-linked in a widened minor groove with the chromophore ring system in the vicinity of the G10-T11 step on one of the two strands in the duplex. The experimental evidence supports this model since the H1{prime} of G10 is shifted dramatically upfield and the H1{prime} proton of T11 is shifted dramatically downfield on complex formation.

  18. Identification and assignment of base pairs in four helical segments of Bacillus megaterium ribosomal 5S RNA and its ribonuclease T1 cleavage fragments by means of 500-MHz proton homonuclear Overhauser enhancements

    SciTech Connect

    Kim, J.H.; Marshall, A.G. )

    1990-01-23

    Three different fragments of Bacillus megaterium ribosomal 5S RNA have been produced by enzymatic cleavage with ribonuclease T1. Fragment A consists of helices II and III, fragment B contains helix IV, and fragment C contains helix I of the universal 5S rRNA secondary structure. All (eight) imino proton resonances in the downfield region (9-15 ppm) of the 500-MHz proton FT NMR spectrum of fragment B have been identified and assigned as G{sub 80}{center dot}C{sub 92}{center dot}G{sub 81}{center dot}C{sub 91}-G{sub 82}{center dot}C{sub 90}-A{sub 83}{center dot}U{sub 89}-C{sub 84}{center dot}G{sub 88} and three unpaired U's in helix IV by proton homonuclear Overhauser enhancement connectivities. The secondary structure in helix IV of the prokaryotic loop is completely demonstrated spectroscopically for the first time in any native or enzyme-cleaved 5S rRNA. In addition, G{sub 21}{center dot}C{sub 58}-A{sub 20}{center dot}U{sub 59}-G{sub 19}{center dot}C{sub 60}-A{sub 18}{center dot}U{sub 61} in helix II, U{sub 32}{center dot}A{sub 46}-G{sub 31}{center dot}C{sub 47}-C{sub 30}{center dot}G{sub 48}-C{sub 29}{center dot}G{sub 49} in helix III, and G{sub 4}{center dot}C{sub 112}-G{sub 5}{center dot}C{sub 111}-U{sub 6}{center dot}G{sub 110} in the terminal stem (helix I) have been assigned by means of NOE experiments on intact 5S rRNA and its fragments A and C. Base pairs in helices I-IV of the universal secondary structure of B. megaterium 5S RNA are described.

  19. [Catheter ablation of atrial fibrillation: Health Technology Assessment Report from the Italian Association of Arrhythmology and Cardiac Pacing (AIAC)].

    PubMed

    Themistoclakis, Sakis; Tritto, Massimo; Bertaglia, Emanuele; Berto, Patrizia; Bongiorni, Maria Grazia; Catanzariti, Domenico; De Fabrizio, Giuseppe; De Ponti, Roberto; Grimaldi, Massimo; Pandozi, Claudio; Tondo, Claudio; Gulizia, Michele

    2011-11-01

    Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and significantly impact patients' quality of life, morbidity and mortality. The number of affected patients is expected to increase as well as the costs associated with AF management, mainly driven by hospitalizations. Over the last decade, catheter ablation techniques targeting pulmonary vein isolation have demonstrated to be effective in treating AF and preventing AF recurrence. This Health Technology Assessment report of the Italian Association of Arrhythmology and Cardiac Pacing (AIAC) aims to define the current role of catheter ablation of AF in terms of effectiveness, efficiency and appropriateness. On the basis of an extensive review of the available literature, this report provides (i) an overview of the epidemiology, clinical impact and socio-economic burden of AF; (ii) an evaluation of therapeutic options other than catheter ablation of AF; and (iii) a detailed presentation of clinical outcomes and cost-benefit ratio associated with catheter ablation. The costs of catheter ablation of AF in Italy were obtained using a bottom-up analysis of a resource utilization survey of 52 hospitals that were considered a representative sample, including 4 Centers that contributed with additional unit cost information in a separate questionnaire. An analysis of budget impact was also performed to evaluate the impact of ablation on the management costs of AF. Results of this analysis show that (1) catheter ablation is effective, safe and superior to antiarrhythmic drug therapy in maintaining sinus rhythm; (2) the cost of an ablation procedure in Italy typically ranges from €8868 to €9455, though current reimbursement remains insufficient, covering only about 60% of the costs; (3) the costs of follow-up are modest (about 8% of total costs); (4) assuming an adjustment of reimbursement to the real cost of an ablation procedure and a 5-10% increase in the annual rate of ablation procedures, after

  20. Synthesis and properties of new DNA cleavage agents based on oxoruthenium(IV)

    SciTech Connect

    Gupta, N.; Grover, N.; Neyhart, G.A.; Singh, P.; Thorp, H.H. )

    1993-02-03

    New aquaruthenium(II) reagents that are capable of being oxidized to hydrooxoruthenium(III) and oxoruthenium(IV) have been prepared. Complexes based on Ru(tpy)(L)OH[sub 2][sup 2+] (L = [eta][sup 2]-tpt, phen, dppz, tmen; tpy = 2,2[prime]:6[prime],2[double prime]-terpyridine, tpt = 2,4,6-tripyridyltriazine, phen = 1,10-phenanthroline, dppz = dipyridophenazine, and tmen = N,N,N[prime],N[prime]-tetramethylethylenediamine) have been prepared and can all be reversibly oxidized to their Ru[sup IV]O forms, which are component DNA cleavage agents, as in Ru(phen)[sub 2](py)O[sup 2+]. In addition to Ru(tpy)([eta][sup 2]-tpt)OH[sub 2][sup 2+], the [eta][sup 3] complex of tpt, Ru(tpy)([eta][sup 3]-tpt)[sup 2+], can also be prepared under similar conditions. In the presence of Ag[sup +] ion, a novel Ru[sub 2]Ag complex can be isolated and has been crystallographically characterized. The complex [Ru(tpy)([eta][sup 3]-tpt)](ClO[sub 4])[sub 2][center dot]0.5AgClO[sub 4][center dot]0.5H[sub 2]O crystallizes in the monoclinic space group A2/A with a = 14.723 (5) [Angstrom], b = 26.061 (6) [Angstrom], c = 22.148 (6) [Angstrom], [beta] = 106.33 (3)[degrees], V = 8155 (5) [Angstrom][sup 3], Z = 4, R = 0.0807, and R[sub w] = 0.1156 for 2,923 reflections with I [ge] 2[sigma](I). The Ru(tpy)OH[sub 2][sup 2+] unit can also be attached to the tmen-AO[sup +] ligand, where a N,N[prime],N[prime]-trimethylethylenediamine function is appended via a (CH[sub 2])[sub 6] linker to the acridine orange intercalator. The Ru(tpy)(tmen-AO)OH[sub 2][sup 3+] complex is an effective cleavage agent, but only when oxidation is performed on the complex prebound to DNA. In homogeneous solution, electrochemically reversible access of only the Ru[sup III]OH form is possible, probably because of oxidation of the polymethylene linker. 25 refs., 11 figs., 9 tabs.

  1. Structural and resonance Raman studies of an oxygen-evolving catalyst. Crystal structure of [(bpy){sub 2}(H{sub 2}O)Ru{sup III}ORu{sup IV}(OH)(bpy){sub 2}](ClO{sub 4}){sub 4}

    SciTech Connect

    Schoonover, J.; Ni, JinFeng; Roecker, L.; White, P.S.; Meyer, T.J. |

    1996-09-25

    The oxidized form of the blue dimer water oxidation catalyst [(bpy){sub 2}(H{sub 2}O)Ru{sup III}ORu{sup IV}(OH)(bpy){sub 2}](ClO{sub 4}){sub 4} (bpy is 2,2{prime}-bipyridine) has been characterized structurally by X-ray crystallography. Comparisons with [(bpy){sub 2}(H{sub 2}O)Ru{sup III}-ORu{sup III}(OH{sub 2})(bpy){sub 2}](ClO{sub 4}){sub 4}{center_dot}2H{sub 2}O, [(bpy){sub 2}ClRu{sup III}ORu{sup IV}Cl(bpy){sub 2}](ClO{sub 4}){sub 3}{center_dot}H{sub 2}O, and [(tpy)(bpy)Os{sup III}OOs{sup IV}(bpy)-(tpy)]Na(ClO{sub 4}){sub 6}{center_dot}3H{sub 2}O (tpy is 2,2{prime}:6{prime},2{double_prime}-terpyridine) reveal that oxidation of Ru{sup III}-O-Ru{sup III} to Ru{sup III}-O-Ru{sup IV} results in significant structural changes at the {mu}-oxo bridge. There is an increase toward linearity along M-O-M, a decrease in the M-O bond distances at the bridge, and an increase in the H{sub 2}O-Ru-O bridge angle. These changes are discussed in the context of the structural requirements for O...O coupling and O{sub 2} evolution in higher oxidation states. Resonance Raman spectra of these and related complexes reveal that internal ligand vibrations as well as overtone and combination bands of an intense, symmetrical M-O-M stretch at 360-400 cm{sup {minus}1} contribute significantly to the Raman spectra. Additional M-O-M bands are identified near 800 cm{sup {minus}1} and, tentatively, near 130 cm{sup {minus}1}. It is not possible to assign bands to Ru-OH{sub 2} or Ru-OH stretches; bands at low energy appear to originate from modes that are highly mixed.

  2. Planar CoB18- Cluster: a New Motif for - and Metallo-Borophenes

    NASA Astrophysics Data System (ADS)

    Chen, Teng-Teng; Jian, Tian; Lopez, Gary; Li, Wan-Lu; Chen, Xin; Li, Jun; Wang, Lai-Sheng

    2016-06-01

    Combined Photoelectron Spectroscopy (PES) and theoretical calculations have found that anion boron clusters (Bn-) are planar and quasi-planar up to B25-. Recent works show that anion pure boron clusters continued to be planar at B27-,B30-,B35- and B36-. B35- and B36- provide the first experimental evidence for the viability of the two-dimensional (2D) boron sheets (Borophene). The 2D to three-dimensional (3D) transitions are shown to happen at B40-,B39- and B28-, which possess cage-like structures. These fullerene-like boron cage clusters are named as Borospherene. Recently, borophenes or similar structures are claimed to be synthesized by several groups. Following an electronic design principle, a series of transition-metal-doped boron clusters (M©Bn-, n=8-10) are found to possess the monocyclic wheel structures. Meanwhile, CoB12- and RhB12- are revealed to adopt half-sandwich-type structures with the quasi-planar B12 moiety similar to the B12- cluster. Very lately, we show that the CoB16- cluster possesses a highly symmetric Cobalt-centered drum-like structure, with a new record of coordination number at 16. Here we report the CoB18- cluster to possess a unique planar structure, in which the Co atom is doped into the network of a planar boron cluster. PES reveals that the CoB18- cluster is a highly stable electronic system with the first adiabatic detachment energy (ADE) at 4.0 eV. Global minimum searches along with high-level quantum calculations show the global minimum for CoB18- is perfectly planar and closed shell (1A1) with C2v symmetry. The Co atom is bonded with 7 boron atoms in the closest coordination shell and the other 11 boron atoms in the outer coordination shell. The calculated vertical detachment energy (VDE) values match quite well with our experimental results. Chemical bonding analysis by the Adaptive Natural Density Partitioning (AdNDP) method shows the CoB18- cluster is π-aromatic with four 4-centered-2-electron (4c-2e) π bonds and one 19

  3. Synthesis, spectral, and structural characterizations of imidazole oxalato molybdenum(IV/V/VI) complexes.

    PubMed

    Chen, Quan-Liang; Chen, Hong-Bin; Cao, Ze-Xing; Zhou, Zhao-Hui

    2013-02-07

    Substitutions of trans-Na(Him)[Mo(2)O(4)(ox)(2)(H(2)O)(2)]·H(2)O (1) and trans-(Him)(2)[Mo(2)O(4)(ox)(2)(H(2)O)(2)] (2) with imidazole result in the formation of the mixed-ligand molybdenum complexes cis-Na(2)[Mo(2)O(4)(ox)(2)(im)(2)]·4.5H(2)O (3), cis-K(2)[Mo(2)O(4)(ox)(2)(im)(2)]·3H(2)O (4), respectively (H(2)ox = oxalic acid; im = imidazole). Further reduction of cis-K(2)[Mo(2)O(4)(ox)(2)(im)(2)]·3H(2)O (4) gives a trinuclear molybdenum(IV) complex K(Him)[Mo(3)O(4)(ox)(3)(im)(3)]·3H(2)O (5), which contains an incomplete cubane cluster [Mo(IV)(3)O(4)](4+). Two novel trinuclear mixed-valence imidazole compounds [Mo(3)O(8)(im)(4)](im)·H(2)O (6) and [Mo(3)O(8)(im)(4)]·H(2)O (7) were obtained by the reduction of (Him)(4)[Mo(8)O(26)(im)(2)] (8). Both 6 and 7 contain a novel Mo(VI)O(4)(Mo(V)(2)O(4)) center, where the [Mo(V)(2)O(4)](2+) unit is linked by [Mo(VI)O(4)](2-) anion. The Mo-Mo bond distances in 1-7 decrease with the decrease of oxidation state of molybdenum. Solid and solution NMR spectra show that imidazole molybdenum compounds 6-8 fully dissociate in solution, where solvated imidazole and imidazolium groups in 6 and 8 could be served as internal references in their solid (13)C NMR spectra. Furthermore, mixed-ligand molybdenum species 3 and 4 are stable in water. Stabilities of 3 and 4 in solution may be attributed to the strong coordination of bidentate oxalate and the formation of hydrogen bond. Dimers 2 and 4 display quasi-reversible redox process, while trimer 6 is irreversible. Bond valence calculations for 1-8 are consistent with their oxidation states of molybdenum atoms. Calculation of the oxidation state in recent structure of iron molybdenum cofactor [MoFe(7)S(9)C(R-homocit)] (FeMo-co) is 3.318.

  4. Barium uranyl diphosphonates

    SciTech Connect

    Nelson, Anna-Gay D.; Alekseev, Evgeny V.; Ewing, Rodney C.; Albrecht-Schmitt, Thomas E.

    2012-08-15

    Three Ba{sup 2+}/UO{sub 2}{sup 2+} methylenediphosphonates have been prepared from mild hydrothermal treatment of uranium trioxide, methylendiphosphonic acid (C1P2) with barium hydroxide octahydrate, barium iodate monohydrate, and small aliquots of HF at 200 Degree-Sign C. These compounds, Ba[UO{sub 2}[CH{sub 2}(PO{sub 3}){sub 2}]{center_dot}1.4H{sub 2}O (Ba-1), Ba{sub 3}[(UO{sub 2}){sub 4}(CH{sub 2}(PO{sub 3}){sub 2}){sub 2}F{sub 6}]{center_dot}6H{sub 2}O (Ba-2), and Ba{sub 2}[(UO{sub 2}){sub 2}(CH{sub 2}(PO{sub 3}){sub 2})F{sub 4}]{center_dot}5.75H{sub 2}O (Ba-3) all adopt layered structures based upon linear uranyl groups and disphosphonate molecules. Ba-2 and Ba-3 are similar in that they both have UO{sub 5}F{sub 2} pentagonal bipyramids that are bridged and chelated by the diphosphonate moiety into a two-dimensional zigzag anionic sheet (Ba-2) and a one-dimensional ribbon anionic chain (Ba-3). Ba-1, has a single crystallographically unique uranium metal center where the C1P2 ligand solely bridges to form [UO{sub 2}[CH{sub 2}(PO{sub 3}){sub 2}]{sup 2-} sheets. The interlayer space of the structures is occupied by Ba{sup 2+}, which, along with the fluoride ion, mediates the structure formed and maintains overall charge balance. - Graphical abstract: Illustration of the stacking of the layers in Ba{sub 3}[(UO{sub 2}){sub 4}(CH{sub 2}(PO{sub 3}){sub 2}){sub 2})F{sub 6}]{center_dot}6H{sub 2}O viewed along the c-axis. The structure is constructed from UO{sub 7} pentagonal bipyramidal units, U(1)O{sub 7}=gray, U(2)O{sub 7}=yellow, barium=blue, phosphorus=magenta, fluorine=green, oxygen=red, carbon=black, and hydrogen=light peach. Highlights: Black-Right-Pointing-Pointer The polymerization of the UO{sub 2}{sup 2+} sites to form uranyl dimers leads to structural variations in compounds. Black-Right-Pointing-Pointer Barium cations stitch uranyl diphosphonate anionic layers together, and help mediate structure formation. Black-Right-Pointing-Pointer HF acts as both a

  5. Hydrothermal syntheses, structures and characterizations of two luminescent cadmium(II) complexes with p-xylenediphosphonic acid and N-donor ligands

    SciTech Connect

    Sun Yanqiong; Hu Jin; Zhang Hanhui; Chen Yiping

    2012-02-15

    Two novel cadmium diphosphonates [Cd(cis-H{sub 4}BDPP)(2,2 Prime -bipy){sub 2}]{center_dot}(trans-H{sub 2}BDPP)]{sub n} (1) and [Cd(trans-H{sub 2}BDPP)(phen)]{sub n} (2) (H{sub 4}BDPP=p-xylenediphosphonic acid, phen=1,10-phenanthroline, 2,2 Prime -bipy=2,2 Prime -bipyridine) were hydrothermally synthesized from p-xylenediphosphonic acid and CdSO{sub 4}{center_dot}3H{sub 2}O with phen or 2,2 Prime -bipy as second ligand components and characterized by means of elemental analyses, IR, TG analysis, luminescence spectroscopy and single crystal X-ray diffraction. Compound 1 consists of a novel one-dimensional (1D) sinusoidal [Cd(cis-H{sub 4}BDPP)(2,2 Prime -bipy){sub 2}] chains and trans-H{sub 2}BDPP anions. Compound 2 possesses a three-dimensional architecture built from double zigzag -Cd-O-P-O-Cd- chains pillared by trans-p-xylylenediphosphonate ligands from four different directions. There are hexagonal channels running along the c-axis and the coordinated phen ligands suspend in the hexagonal channels. The results indicate that p-xylenediphosphonic acid can adopt varied coordination modes and conformations in the formation of the complexes and the influence of the N-donor ligands on the structure of the complexes is discussed. - Graphical abstract: Two new cadmium diphosphonates were obtained by using two different auxiliary ligands. The influence of the N-donor ligands on the structure of the complexes is discussed. Highlights: Black-Right-Pointing-Pointer The first example of cadmium(II)-p-xylenediphosphonates templated by second ligand. Black-Right-Pointing-Pointer The role of size of the auxiliary ligand on the structure of cadmium p-xylenediphosphonates. Black-Right-Pointing-Pointer The cis and trans configurations of p-xylenediphosphonates exist in the same crystal structure. Black-Right-Pointing-Pointer Three-dimensional 4-connected framework with PtS network topology.

  6. Intervalence charge transfer luminescence: The anomalous luminescence of cerium-doped Cs{sub 2}LiLuCl{sub 6} elpasolite

    SciTech Connect

    Seijo, Luis; Barandiarán, Zoila

    2014-12-07

    The existence of intervalence charge transfer (IVCT) luminescence is reported. It is shown that the so called anomalous luminescence of Ce-doped elpasolite Cs{sub 2}LiLuCl{sub 6}, which is characterized mainly by a very large Stokes shift and a very large band width, corresponds to an IVCT emission that takes place in Ce{sup 3+}–Ce{sup 4+} pairs, from the 5de{sub g} orbital of Ce{sup 3+} to 4f orbitals of Ce{sup 4+}. Its Stokes shift is the sum of the large reorganization energies of the Ce{sup 4+} and Ce{sup 3+} centers formed after the fixed-nuclei electron transfer and it is equal to the energy of the IVCT absorption commonly found in mixed-valence compounds, which is predicted to exist in this material and to be slightly larger than 10 000 cm{sup −1}. The large band width is the consequence of the large offset between the minima of the Ce{sup 3+}–Ce{sup 4+} and Ce{sup 4+}–Ce{sup 3+} pairs along the electron transfer reaction coordinate. This offset is approximately 2√(3) times the difference of Ce–Cl equilibrium distances in the Ce{sup 3+} and Ce{sup 4+} centers. It is shown that the energies of the peaks and the widths of IVCT absorption and emission bands can be calculated ab initio with reasonable accuracy from diabatic energy surfaces of the ground and excited states and that these can be obtained, in turn, from independent calculations on the donor and acceptor active centers. We obtained the energies of the Ce{sup 3+} and Ce{sup 4+} active centers of Ce-doped Cs{sub 2}LiLuCl{sub 6} by means of state-of-the-art wave-function-theory spin-orbit coupling relativistic calculations on the donor cluster (CeCl{sub 6}Li{sub 6}Cs{sub 8}){sup 11+} and the acceptor cluster (CeCl{sub 6}Li{sub 6}Cs{sub 8}){sup 12+} embedded in a quantum mechanical embedding potential of the host. The calculations provide interpretations of unexplained experimental observations as due to higher energy IVCT absorptions, and allow to reinterpret others. The existence of

  7. A series of 2D metal-quinolone complexes: Syntheses, structures, and physical properties

    SciTech Connect

    He, Jiang-Hong; Xiao, Dong-Rong; Chen, Hai-Yan; Sun, Dian-Zhen; Yan, Shi-Wei; Wang, Xin; Ye, Zhong-Li; Luo, Qun-Li; Wang, En-Bo

    2013-02-15

    Six novel 2D metal-quinolone complexes, namely [Cd(cfH)(bpdc)]{center_dot}H{sub 2}O (1), [M(norfH)(bpdc)]{center_dot}H{sub 2}O (M=Cd (2) and Mn (3)), [Mn{sub 2}(cfH)(odpa)(H{sub 2}O){sub 3}]{center_dot}0.5H{sub 2}O (4), [Co{sub 2}(norfH)(bpta)({mu}{sub 2}-H{sub 2}O)(H{sub 2}O){sub 2}]{center_dot}H{sub 2}O (5) and [Co{sub 3}(saraH){sub 2}(Hbpta){sub 2}(H{sub 2}O){sub 4}]{center_dot}9H{sub 2}O (6) (cfH=ciprofloxacin, norfH=norfloxacin, saraH=sarafloxacin, bpdc=4,4 Prime -biphenyldicarboxylate, odpa=4,4 Prime -oxydiphthalate, bpta=3,3 Prime ,4,4 Prime -biphenyltetracarboxylate) have been synthesized and characterized. Compounds 1-3 consist of 2D arm-shaped layers based on the 1D {l_brace}M(COO){r_brace}{sub n}{sup n+} chains. Compounds 4 and 5 display 2D structures based on tetranuclear manganese or cobalt clusters with (3,6)-connected kgd topology. Compound 6 exhibits a 2D bilayer structure, which represents the first example of metal-quinolone complexes with 2D bilayer structure. By inspection of the structures of 1-6, it is believed that the long aromatic polycarboxylate ligands are important for the formation of 2D metal-quinolone complexes. The magnetic properties of compounds 3-6 was studied, indicating the existence of antiferromagnetic interactions. Furthermore, the luminescent properties of compounds 1-2 are discussed. - Graphical abstract: Six novel 2D metal-quinolone complexes have been prepared by self-assemblies of the quinolones and metal salts in the presence of long aromatic polycarboxylates. Highlights: Black-Right-Pointing-Pointer Compounds 1-3 consist of novel 2D arm-shaped layers based on the 1D {l_brace}M(COO){r_brace}{sub n}{sup n+} chains. Black-Right-Pointing-Pointer Compounds 4 and 5 are two novel 2D layers based on tetranuclear Mn or Co clusters with kgd topology. Black-Right-Pointing-Pointer Compound 6 is the first example of metal-quinolone complexes with 2D bilayer structure. Black-Right-Pointing-Pointer Compounds 1-6 represent six unusual

  8. Hydrothermal syntheses, crystal structures and luminescence properties of zinc(II) and cadmium(II) coordination polymers based on bifunctional 3,2 Prime :6 Prime ,3 Prime Prime -terpyridine-4 Prime -carboxylic acid

    SciTech Connect

    Li, Na; Guo, Hui-Lin; Hu, Huai-Ming; Song, Juan; Xu, Bing; Yang, Meng-Lin; Dong, Fa-Xin; Xue, Gang-Lin

    2013-02-15

    Five new coordination polymers, [Zn{sub 2}(ctpy){sub 2}Cl{sub 2}]{sub n} (1), [Zn{sub 2}(ctpy){sub 2}(ox)(H{sub 2}O){sub 2}]{sub n} (2), [Zn{sub 2}(ctpy)(3-btc)(H{sub 2}O)]{sub n}{center_dot}0.5nH{sub 2}O (3), [Cd(ctpy){sub 2}(H{sub 2}O)]{sub n} (4), [Cd{sub 4}(ctpy){sub 2}(2-btc){sub 2}(H{sub 2}O){sub 2}]{sub n}{center_dot}2nH{sub 2}O (5), (Hctpy=3,2 Prime :6 Prime ,3 Prime Prime -terpyridine-4 Prime -carboxylic acid, H{sub 2}ox=oxalic acid, H{sub 3}(3-btc)=1,3,5-benzenetricarboxylic acid, H{sub 3}(2-btc)=1,2,4-benzenetricarboxylic acid) have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction. Compounds 1-2 are a one-dimensional chain with weak interactions to form 3D supramolecular structures. Compound 3 is a 4-nodal 3D topology framework comprised of binuclear zinc units and (ctpy){sup -} anions. Compound 4 shows two dimensional net. Compound 5 is a (4,5,6)-connected framework with {l_brace}4{sup 4}{center_dot}6{sup 2}{r_brace}{l_brace}4{sup 6}{center_dot}6{sup 4}{r_brace}{sub 2}{l_brace}4{sup 9}{center_dot}6{sup 6}{r_brace} topology. In addition, the thermal stabilities and photoluminescence properties of 1-5 were also studied in the solid state. - Graphical abstract: Five new Zn/Cd compounds with 3,2 Prime :6 Prime ,3 Prime Prime -terpyridine-4 Prime -carboxylic acid were prepared. The photoluminescence and thermal stabilities properties of 1-5 were investigated in the solid state. Highlights: Black-Right-Pointing-Pointer Five new zinc/cadmium metal-organic frameworks have been hydrothermal synthesized. Black-Right-Pointing-Pointer The structural variation is attributed to the diverse metal ions and auxiliary ligand. Black-Right-Pointing-Pointer Compounds 1-5 exhibit 1D ring chain, 2D layer and 3D open-framework, respectively. Black-Right-Pointing-Pointer These compounds exhibit strong solid state luminescence emission at room temperature.

  9. FY04 Engineering Technology Reports Laboratory Directed Research and Development

    SciTech Connect

    Sharpe, R M

    2005-01-27

    areas. Their LDRD projects are the key resources to attain this competency, and, as such, nearly all of Engineering's portfolio falls under one of the five Centers. The Centers and their Directors are: (1) Center for Computational Engineering: Robert M. Sharpe; (2) Center for Microtechnology and Nanotechnology: Raymond P. Mariella, Jr.; (3) Center for Nondestructive Characterization: Harry E. Martz, Jr.; (4) Center for Precision Engineering: Keith Carlisle; and (5) Center for Complex Distributed Systems: Gregory J. Suski, Acting Director.

  10. Novel Potent Hepatitis C Virus NS3 Serine Protease Inhibitors Derived from Proline-Based Macrocycles

    SciTech Connect

    Chen, Kevin X.; Njoroge, F. George; Arasappan, Ashok; Venkatraman, Srikanth; Vibulbhan, Bancha; Yang, Weiying; Parekh, Tejal N.; Pichardo, John; Prongay, Andrew; Cheng, Kuo-Chi; Butkiewicz, Nancy; Yao, Nanhua; Madison, Vincent; Girijavallabhan, Viyyoor

    2008-06-30

    The hepatitis C virus (HCV) NS3 protease is essential for viral replication. It has been a target of choice for intensive drug discovery research. On the basis of an active pentapeptide inhibitor, 1, we envisioned that macrocyclization from the P2 proline to P3 capping could enhance binding to the backbone Ala156 residue and the S4 pocket. Thus, a number of P2 proline-based macrocyclic {alpha}-ketoamide inhibitors were prepared and investigated in an HCV NS3 serine protease continuous assay (K*{sub i}). The biological activity varied substantially depending on factors such as the ring size, number of amino acid residues, number of methyl substituents, type of heteroatom in the linker, P3 residue, and configuration at the proline C-4 center. The pentapeptide inhibitors were very potent, with the C-terminal acids and amides being the most active ones (24, K*{sub i} = 8 nM). The tetrapeptides and tripeptides were less potent. Sixteen- and seventeen-membered macrocyclic compounds were equally potent, while fifteen-membered analogues were slightly less active. gem-Dimethyl substituents at the linker improved the potency of all inhibitors (the best compound was 45, K*{sub i} = 6 nM). The combination of tert-leucine at P3 and dimethyl substituents at the linker in compound 47 realized a selectivity of 307 against human neutrophil elastase. Compound 45 had an IC{sub 50} of 130 nM in a cellular replicon assay, while IC{sub 50} for 24 was 400 nM. Several compounds had excellent subcutaneous AUC and bioavailability in rats. Although tripeptide compound 40 was 97% orally bioavailable, larger pentapeptides generally had low oral bioavailability. The X-ray crystal structure of compounds 24 and 45 bound to the protease demonstrated the close interaction of the macrocycle with the Ala156 methyl group and S4 pocket. The strategy of macrocyclization has been proved to be successful in improving potency (>20-fold greater than that of 1) and in structural depeptization.

  11. Chemical and Mineralogical Characterization of Arsenic, Lead, Chromium, and Cadmium in a Metal-contaminated Histosol

    SciTech Connect

    Gao, X.; Schulze, D

    2010-01-01

    The chemical and mineralogical forms of As, Pb, Cr, and Cd were studied in a metal-contaminated organic soil (Histosol) that received runoff and seepage water from a site that was once occupied by a lead smelter. Soil samples were collected from different depth intervals during both wet and dry seasons and analyzed using bulk powder X-ray diffraction (XRD), synchrotron-based micro X-ray diffraction ({mu}-XRD), and micro X-ray fluorescence ({mu}-SXRF) spectroscopy. There was a clear pattern of mineral distribution with depth that indicated the presence of an intense redox gradient. The oxidized reddish brown surface layer (0-10 cm) was dominated by goethite ({alpha}-FeOOH) and poorly crystalline akaganeite ({beta}-FeOOH). Lead and arsenic were highly associated with these Fe oxides, possibly by forming inner-sphere surface complexes. Gypsum (CaSO{sub 4} {center_dot} 2H{sub 2}O) was abundant in the layer as well, particularly for samples collected during dry periods. Fe(II)-containing minerals, such as magnetite (Fe{sub 3}O{sub 4}) and siderite (FeCO{sub 3}), were identified in the intermediate layers (10-30 cm) where the reductive dissolution of Fe(III) oxides occurred. A number of high-temperature minerals, such as mullite (3Al{sub 2}O{sub 3} {center_dot} 2Si{sub 2}O), corundum ({alpha}-Al{sub 2}O{sub 3}), hematite ({alpha}-Fe{sub 2}O{sub 3}), and wustite (FeO) were identified in the subsurface and they probably formed as a result of a burning event. Several sulfide minerals were identified in the most reduced layers at depths > 30 cm. They included realgar (AsS), alacranite (As{sub 4}S{sub 4}), galena (PbS), and sphalerite (Zn, Fe{sup 2+})S, and a series of Fe sulfides, including greigite (Fe{sup 2+}Fe{sub 2}{sup 3+} S{sub 4}), pyrrhotite (Fe{sub 1-x}S), mackinawite (FeS), marcasite (FeS{sub 2}), and pyrite (FeS{sub 2}). Most of these minerals occurred as almost pure phases in sub-millimeter aggregates and appeared to be secondary phases that had precipitated from

  12. Versatility of Y-family Sulfolobus solfataricus DNA Polymerase Dpo4 in Translesion Synthesis Past Bulky N[superscript 2]-Alkylguanine Adducts

    SciTech Connect

    Zhang, Huidong; Eoff, Robert L.; Kozekov, Ivan D.; Rizzo, Carmelo J.; Egli, Martin; Guengerich, F. Peter

    2009-09-25

    In contrast to replicative DNA polymerases, Sulfolobus solfataricus Dpo4 showed a limited decrease in catalytic efficiency (k{sub cat}/K{sub m}) for insertion of dCTP opposite a series of N{sup 2}-alkylguanine templates of increasing size from (methyl (Me) to (9-anthracenyl)-Me (Anth)). Fidelity was maintained with increasing size up to (2-naphthyl)-Me (Naph). The catalytic efficiency increased slightly going from the N{sup 2}-NaphG to the N{sup 2}-AnthG substrate, at the cost of fidelity. Pre-steady-state kinetic bursts were observed for dCTP incorporation throughout the series (N{sup 2}-MeG to N{sup 2}-AnthG), with a decrease in the burst amplitude and k{sub pol}, the rate of single-turnover incorporation. The pre-steady-state kinetic courses with G and all of the six N{sup 2}-alkyl G adducts could be fit to a general DNA polymerase scheme to which was added an inactive complex in equilibrium with the active ternary Dpo4 {center_dot} DNA {center_dot} dNTP complex, and only the rates of equilibrium with the inactive complex and phosphodiester bond formation were altered. Two crystal structures of Dpo4 with a template N{sup 2}-NaphG (in a post-insertion register opposite a 3'-terminal C in the primer) were solved. One showed N{sup 2}-NaphG in a syn conformation, with the naphthyl group located between the template and the Dpo4 'little finger' domain. The Hoogsteen face was within hydrogen bonding distance of the N4 atoms of the cytosine opposite N{sup 2}-NaphG and the cytosine at the -2 position. The second structure showed N{sup 2}-Naph G in an anti conformation with the primer terminus largely disordered. Collectively these results explain the versatility of Dpo4 in bypassing bulky G lesions.

  13. Synthesis, characterization, and reactivity of sulfided hexanuclear molybdenum cluster compounds

    SciTech Connect

    Spink, D.

    1990-09-21

    Hexanuclear molybdenum clusters with mixed chloride and sulfide bridging ligands were prepared by reacting {alpha}-MoCl{sub 2} with sodium hydrosulfide in the presence of sodium butoxide. The resulting species, Mo{sub 6}Cl{sub (8-x)}S{sub x}{center dot}npy(x {congruent} 3.6, n {congruent} 4, py = pyridine), was pyrophoric and insoluble. The mixed sulfide chloride cluster species Mo{sub 6}S{sub 4}Cl{sub 4}{center dot}6OPEt{sub 3} and Mo{sub 6}S{sub {approximately}5}Cl{sub {approximately}3}{center dot}6PEt{sub 3} and Mo{sub 6}S{sub 8}{center dot}6PEt{sub 3} were isolated and characterized. Phosphorus-31 nuclear magnetic resonance, electron paramagnetic resonance, and UV/visible spectra were obtained for each fraction. The completely sulfided cluster, Mo{sub 6}S{sub 8}{center dot}6PEt{sub 3}, was prepared similarly and used in various experiments as a possible precursor to Chevrel phase materials of the type Mo{sub 6}S{sub 8}or M{sub n}Mo{sub 6}S{sub 8}. With the goal of removing all of the triethylphosphine ligands, Mo{sub 6}S{sub 8}{center dot}6PEt{sub 3} was reacted with the transition metal carbonyls molybdenum hexacarbonyl and dicobalt octacarbonyl. Reaction on the molecular sulfide cluster with copper(I) chloride in toluene gave a completely insoluble product. The reaction of Mo{sub 6}S{sub 8}{center dot}6PEt{sub 3} with propylene sulfide gave a product whose infrared spectra showed only very weak peaks associated with coordinated triethylphosphine. The elemental analysis of this product fit the formula Mo{sub 6}S{sub 8}{center dot}5SPEt{sub 3}. Reactivity of the outer ligands of the Mo{sub 6}S{sub 8}{center dot}npy and Mo{sub 6}S{sub 8}{center dot}(6{minus}x)PrNH{sub x} clusters were investigated. Crystalline Mo{sub 6}S{sub 8}{center dot}6THT was recovered from the reaction of the n-propylamine derivative with THT. A crystal structure determination was done. 87 refs., 12 fig., 15 tabs.

  14. The high-pressure-high-temperature behavior of bassanite

    SciTech Connect

    Comodi, Paola; Nazzareni, Sabrina; Dubrovinsky, Leonid; Merlini, Marco

    2010-02-11

    The pressure evolution of bassanite (CaSO{sub 4} {center_dot} 1/2 H{sub 2}O) was investigated by synchrotron X-ray powder diffraction along three isotherms: at room temperature up to 33 GPa, at 109 C up to 22 GPa, and at 200 C up to 12 GPa. The room-temperature cell-volume data, from 0.001 to 33 GPa, were fitted to a third-order Birch-Murnaghan equation-of-state, and a bulk modulus K{sub 0} = 86(7) GPa with K' = 2.5(3) was obtained. The axial compressibility values are {beta}{sub a} = 3.7(2), {beta}{sub b} = 3.6(1), and {beta}{sub c} = 2.8(1) GPa{sup -1} (x10{sup -3}) showing a slightly anisotropic behavior, with the least compressible direction along c axis. The strain tensor analysis shows that the main deformation occurs in the (010) plane in a direction 18{sup o} from the a axis. The bulk moduli for isotherms 109 and 200 C, were obtained by fitting cell-volume data with a second-order Birch-Murnaghan equation-of-state, with K' fixed at 4, and were found to be K{sub 109} = 79(4) GPa and K{sub 200} = 63(7) GPa, respectively. The axial compressibility values for isotherm 109 C are {beta}{sub a} = 2.4(1), {beta}{sub b} = 3.0(1), {beta}{sub c} = 2.5(1) (x10{sup -3}) GPa{sup -1}, and for isotherm 200 C they are {beta}{sub a} = 3.5(3), {beta}{sub b} = 3.4(3), {beta}{sub c} = 2.6(4) (x10{sup -3}) GPa{sup -1}. These two bulk moduli and the 20 C bulk modulus, K{sub 0,20} = 69(8) recalculated to a second-order Birch-Murnaghan EoS to be consistent, as well as the axial compressibilities, are similar for the three isotherms indicating that the thermal effect on the bulk moduli is not significant up to 200 C. The size variation of the pseudo-hexagonal channel with pressure and temperature indicates that the sulfate 'host' lattice and the H{sub 2}O 'guest' molecule in bassanite do not undergo strong change up to 33 GPa and 200 C.

  15. Blood transfusion and alloimmunization in patients with thalassemia: multicenter study.

    PubMed

    Azarkeivan, Azita; Ansari, Shahla; Ahmadi, Mohammad Hossein; Hajibeigy, Bashir; Maghsudlu, Mahtab; Nasizadeh, Soheila; Shaigan, Mojgan; Toolabi, Abdolmajid; Salahmand, Mitra

    2011-09-01

    One of transfusion's side effects is alloimmunization against red blood cell (RBC) antigens. Early diagnosis by antibody screening is an important step in the detection of these alloantibodies. The authors studied the frequency of alloimmunization in thalassemic patients of 4 centers (2 adult and 2 pediatric centers) and compared the rates in children (up to 15 years) and adults. Antibody screening tests were performed by gel method according to its standard pattern and respective program. In positive cases, antibody identification test by gel method was performed. Eight hundred thirty-five patients were studied; 548 (65.6%) were adults (mean age = 24.5), and 287 (34.4%) cases were pediatrics (mean age = 10.05). Of these patients, 74.1% had no history of transfusion reaction, whereas 21 (2.5%) had hemolytic complications. Seventy-eight (9.3%) exhibited allergic symptoms, and 117 (14%) cases experienced febrile reactions during transfusion. Antibody screening showed positive results in 22 pediatric cases (7.7%) and 79 adults (14.4%); 72 (71.3%), 19 (18.8%), 3 (3%), and 1 (1%) cases exhibited single, double, triple, and autoantibodies, respectively. Anti-Kell antibody was seen in 34 (33.7%) cases, anti-D was seen in 11 (10.9%) cases, and anti-E in was seen in 10 (9.9%) cases. The authors observed 8 anti-D+C (7.9%) cases, 1 anti-D+E (1%), 3 anti-Kell+E, 3 anti-Kell+Kpa (3%), and 1 anti-Kell+D double antibodies. These antibodies were also a combination of Rh subgroups or Rh and Kell subgroups. The authors observed meaningful relations between history of transfusion reactions and age with antibody screening results (P = .005). Based on alloantibodies types, more than two thirds of them were Rh subgroups and Kell groups. Phenotype determination of RBCs before beginning chronic blood transfusion and careful cross-matching with Kell and Rh subgroups in addition to ABO may help reduce alloimmunization in chronic transfusion patients.

  16. Homolytic dissociation of the vulcanization accelerator tetramethylthiuram disulfide (TMTD) and structures and stabilities of the related radicals Me2NCSn* (n = 1-4).

    PubMed

    Steudel, Ralf; Steudel, Yana; Mak, Adrian Matthew; Wong, Ming Wah

    2006-12-08

    The homolytic dissociation of the important vulcanization accelerator tetramethylthiuram disulfide (TMTD) has been studied by ab initio calculations according to the G3X(MP2) and G3X(MP2)-RAD theories. Homolytic cleavage of the SS bond requires a low enthalpy of 150.0 kJ mol-1, whereas 268.0 kJ mol-1 is needed for the dissociation of one of the C-S single bonds. To cleave one of the SS bonds of the corresponding trisulfide (TMTT) requires 191.1 kJ mol-1. Me2NCS2* is a particularly stable sulfur radical as reflected in the low S-H bond dissociation enthalpy of the corresponding acid Me2NC(=S)SH (301.7 kJ mol-1). Me2NCS2* (2B2) is a sigma radical characterized by the unpaired spin density shared equally between the two sulfur atoms and by a 4-center (NCS2) delocalized pi system. The ESR g-tensors of the radicals Me2NCSn* (n = 1-3) have been calculated. Both TMTD and the mentioned radicals form stable chelate complexes with a Li+ cation, which here serves as a model for the zinc ions used in accelerated rubber vulcanization. Although the binding energy of the complex [Li(TMTD)]+ is larger than that of the isomeric species [Li(S2CNMe2)2]+ (12), the dissociation enthalpy of TMTD as a ligand is smaller (125.5 kJ mol-1) than that of free TMTD. In other words, the homolytic dissociation of the SS bonds of TMTD is facilitated by the presence of Li+ ions. The sulfurization of TMTD in the presence of Li+ to give the paramagnetic complex [Li(S3CNMe2)2]+ is strongly exothermic. These results suggest that TMTD reacts with naked zinc ions as well as with the surface atoms of solid zinc oxide particles in an analogous manner producing highly reactive complexes, which probably initiate the crosslinking process during vulcanization reactions of natural or synthetic rubber accelerated by TMTD/ZnO.

  17. Effect of CPAP on Cardiac Function in Minimally Symptomatic Patients with OSA: Results from a Subset of the MOSAIC Randomized Trial

    PubMed Central

    Craig, Sonya; Kylintireas, Ilias; Kohler, Malcolm; Nicoll, Debby; Bratton, Daniel J.; Nunn, Andrew J.; Leeson, Paul; Neubauer, Stefan; Stradling, John R.

    2015-01-01

    Study Objectives: Minimally symptomatic obstructive sleep apnea (OSA) is highly prevalent, and the effects of continuous positive airway pressure (CPAP) on myocardial function in these patients are unknown. The MOSAIC randomized, controlled trial of CPAP for minimally symptomatic OSA assessed the effect of CPAP on myocardial function in a subset of patients. Methods: Two centers taking part in the MOSAIC trial randomized 238 patients in parallel to 6 months of CPAP (120) or standard care (118). Of these, 168 patients had echocardiograms, and 68 patients had a cardiac magnetic resonance scan (CMR). A larger group (314) from 4 centers had brain natriuretic peptide (BNP) measured. Results: Mean (SD) baseline oxygen desaturation index (ODI) and Epworth sleepiness score (ESS) were 13.5 (13.2), and 8.4 (4.0), respectively. CPAP significantly reduced ESS and ODI. Baseline LV ejection fraction (LVEF) was well preserved (60.4%). CPAP had no significant effect on echo-derived left atrial (LA) area (−1.0 cm2, 95% CI −2.6 to +0.6, p = 0.23) or early to late left ventricular filling velocity (E/A) ratio (−0.01, 95% CI −0.07 to +0.05, p = 0.79). There was a small change in echo-derived LV end diastolic volume (EDV) with CPAP (−5.9 mL, 95% CI −10.6 to −1.2, p = 0.015). No significant changes were detected by CMR on LV mass index (+1.1 g/m2, 95% CI −5.9 to +8.0, p = 0.76) or LVEF (+0.8%, 95% CI −1.2 to +2.8, p = 0.41). CPAP did not affect BNP levels (p = 0.16). Conclusions: Six months of CPAP therapy does not change cardiac functional or structural parameters measured by echocardiogram or CMR in patients with minimally symptomatic mild-to-moderate OSA. Clinical Trial Registration: ISRCTN 34164388 (http://isrctn.org). Citation: Craig S, Kylintireas I, Kohler M, Nicoll D, Bratton DJ, Nunn AJ, Leeson P, Neubauer S, Stradling JR. Effect of CPAP on cardiac function in minimally symptomatic patients with OSA: results from a subset of the MOSAIC randomized trial. J Clin

  18. Association of CD4+ T cell subpopulations and psychological stress measures in women living with HIV.

    PubMed

    Rehm, Kristina E; Konkle-Parker, Deborah

    2017-01-24

    Psychological stress is a known immunomodulator. In individuals with HIV, depression, the most common manifestation of increased psychological stress, can affect immune function with lower CD4+ T cell counts correlating with higher levels of depression. It is unknown how other forms of psychological stress can impact immune markers in people living with HIV. We conducted a cross-sectional study to determine how CD4+ T cell subpopulations correlated with different forms of psychological stress. We recruited 50 HIV-positive women as part of the Women's Interagency HIV Study. We assessed perceived stress, worry, acute anxiety, trait anxiety, and depression through self-report questionnaires and CD4+ T cell subpopulations using flow cytometry. Our sample was 96% African-American with a mean ± SD age and body mass index of 42 ± 8.8 years and 36.6 ± 11.5 kg/m(2), respectively. The mean ± SD scores on the psychological measures were as follows: Perceived Stress Scale (PSS), 16.5 ± 6.4; Penn State Worry Questionnaire (PSWQ), 47.7 ± 13.8; State-Trait Anxiety Inventory - State (STAIS), 39.1 ± 12.3; State-Trait Anxiety Inventory - Trait (STAIT), 40.2 ± 11.4; Center for Epidemiological Studies Depression Scale (CES-D), 15.6 ± 11.4. The mean + SD values for the immune parameters were as follows: regulatory T cells (Treg), 1.25% ± 0.7; T helper 1 (Th1), 14.9% ± 6.1; T helper 2 (Th2), 3.8% ± 2; Th1/Th2 ratio, 4.6 ± 3; and CD4+ T cell count (cells/mm(3)), 493 ± 251. Treg levels positively correlated with PSS, STAIS, and STAIT. CD4+ T cell count negatively correlated with PSS, PSWQ, STAIS, STAIT, and CES-D. These data suggest that immune function may be impacted by various forms of psychological stress in HIV-positive women. Interventions that target stress reduction may be useful in improving immune parameters and quality of life.

  19. Luminescence dynamics and {sup 13}C NMR characteristics of dinuclear complexes exhibiting coupled lanthanide(III) cation pairs

    SciTech Connect

    Matthews, K.D.; Bailey-Folkes, S.A.; Kahwa, I.A.

    1992-08-20

    Luminescence and cross-polarization magic angle spinning (CP-MAS) {sup 13}C NMR properties of lanthanide dinuclear macrocyclic complexes of a compartmental Schiff base chelate (1) derived from the condensation of 2,6-diformyl-p-cresol and 3,6-dioxa-1,8-octanediamine are reported. The Schiff base chromophore in 1 is a strong light absorber and an efficient sensitizer for intense Tb{sup 3+}({sup 5}D{sub 4}) and Eu{sup 3+}({sup 5}D{sub 0})(T < 110 K ) emission which does not exhibit self-quenching effects. Emission from Tb{sup 3+} is sensitized by the ligand singlet state; in striking contrast, Eu{sup 3+} emission is sensitized by the triplet state and reveals an unusual nonradiative quenching process at T > 110 K with a thermal barrier of {approx} 2300 cm{sup {minus}1}. Weak emission is observed from Dy{sup 3+}({sup 4}F{sub 9/2}), Sm{sup 3+}({sup 4}G{sub 5/2}), and Pr{sup 3+}({sup 1}D{sub 2}) diluted in Gd{sup 3+} (i.e., from Gd{sup 3+}-Ln{sup 3+} heteropairs, Ln = Pr, Sm, Dy). Intramolecular metal-metal (Ln-Ln = 4 {Angstrom}) interactions account for the greatly quenched emission from Sm{sup 3+}-Sm{sup 3+} and Dy{sup 3+}-Dy{sup 3+} homopairs compared to Gd{sup 3+}-Ln heteropairs (Ln = Sm, Dy). Gd{sup 3+}-Ln{sup 3+} emission lifetimes at 77 K are 1610 (Tb{sup 3+}), 890 (Eu{sup 3+}), 14 (Dy{sup 3+}) and {approx} 13 {mu}s (Sm{sup 3+}). Nonradiative relaxation processes at 77 K in dilute Ln{sup 3+}:Gd{sub 2}1(NO{sub 3}){sub 4}{center_dot}H{sub 2}O, being temperature independent for Sm{sup 3+} and Eu{sup 3+} but temperature dependent for Tb{sup 3+}, follow the energy gap law with {alpha} {approx} - 10{sup {minus}3} cm and B {approx} 2 x 10{sup 8} s{sup {minus}1}. CP-MAS data show paramagnetic broadening of {sup 13}C resonances which increases with the magnetic moment of Ln{sup 3+}. Surprisingly, no significant shifts in resonance positions corresponding to the changing nature of paramagnetic Ln{sup 3+} ions are observed. 43 refs., 8 figs., 2 tabs.

  20. Solution structure and dynamics of lanthanide complexes of the macrocyclic polyamino carboxylate DTPA-dien. NMR study and crystal structures of the lanthanum(III) and europium(III) complexes

    SciTech Connect

    Franklin, S.J.; Raymond, K.N.

    1994-12-07

    An 18-membered macrocyclic DTPA-bis(amide) ligand (DTPA = diethylenetriaminepentaacetic acid) containing a heteroatom in the amide link has been prepared via the condensation of DTPA-dianhydride and diethylenetriamine. The solution structures of the two isomeric pairs present in the Ln(III) complexes of DTPA-dien have been investigated by {sup 1}H NMR. The structures of the lanthanum(III) and europium(III) DTPA-dien complexes have been determined by X-ray analysis. [La(DTPA-dienH{sup +})H{sub 2}O]{sub 2}(CF{sub 3}SO{sub 3}{sup -}){sub 2}{center_dot}18H{sub 2}O (I) crystallizes as a carboxylate-bridged dimer about a center of inversion in the orthorhombic space group Pbca with a = 12.626(2) {angstrom}, b = 21.405(3) {angstrom}, c = 26.422(9) {angstrom}, and Z = 8. Each lanthanum ion is 11-coordinate with octadentate ligand coordination, an {eta}{sup 2} bridging carboxylate, and one water. [Eu(DTPA-dienH{sup +})]{sub 4}(CF{sub 3}SO{sub 3}{sup -}){sub 4}{center_dot}6NaCF{sub 3}SO{sub 3}{center_dot}20H{sub 2}O (II) crystallizes as a carboxylate-bridged tetramer with two crystallographically independent Eu(III) positions (Z = 8 for each) in the monoclinic space group C2/c: a = 30.94(1) {angstrom}, b = 23.456(3) {angstrom}, c = 22.611(4) {angstrom}, {beta} = 105.78(2){degrees}. The coordination geometries about Eu1 and Eu2 are nearly identical and are described as a nine-coordinate tricapped trigonal prism with octadentate ligand coordination plus an {eta}{sup 1} bridging carboxylate. The tendency to oligomerize is attributed to the constraints imposed by the macrocycle and the hydrogen bonding available with the link heteroatom. The structural differences between the two complexes are attributed to a difference in La(III) and Eu(III) ionic size.

  1. Nurnet- A case of crowdsourcing for geographic knowledge production.

    NASA Astrophysics Data System (ADS)

    Spanu, Valentina; Demontis, Roberto; Lorrai, Eva; Muscas, Laura

    2015-04-01

    Nurnet - The net of the Nuraghes (http://www.nurnet.it) is a Foundation of Participation aiming to promote the culture of the Pre-Nuragical (3200-2700 BC) and Nuragical period (up to the 2nd century AD) in the island of Sardinia (Italy). It is fed by a net of conventional social connections or through social web- networks empowered by private citizens, agents and public administrations sharing the same goals and interests. CRS4 (Center for Advanced Studies, Research and Development in Sardinia), in collaboration with Nurnet Foundation, developed a geoportal (http://nurnet.crs4.it/nurnetgeo/) on the web, at the moment as a beta version, enable the users to access and share information. The application is based on Geographic Information System (GIS) and Participatory Geographic Information System (PGIS) and it manages several types of information like archaeological sites, artifacts and museum information. Such information comes from the users of the portal and from other sources that make the data available, according to the "open data" philosophy: free data accessible to anyone. The users are encouraged to generate and manage information of archaeological sites in the Italian island of Sardinia about location, history, preservation of the archaeological patrimony, pictures and videos to enrich a wide geo-database pertaining the big heritage of this region in every place there are nuraghes, dolmens domus de janas, menhirs, villages and sacred pits. A specific data model has been created, the geo-attribute is in WGS84 and it can be a point, a line or a polygon. There are three types of actors: viewers, editors and validators. The viewer can query data with a map or a form; the editor can insert and update data through maps using Google or Open Street Map as base layer; the validators are the experts working behind the geoportal: they evaluate and validate the data quality (archaeologists for example). To implement the geoportal, open source software has been used and

  2. Analysis of Parallel Burn Without Crossfeed TSTO RLV Architectures and Comparison to Parallel Burn With Crossfeed and Series Burn Architectures

    NASA Technical Reports Server (NTRS)

    Smith, Garrett; Phillips, Alan

    2002-01-01

    There are currently three dominant TSTO class architectures. These are Series Burn (SB), Parallel Burn with crossfeed (PBw/cf), and Parallel Burn without crossfeed (PBncf). The goal of this study was to determine what factors uniquely affect PBncf architectures, how each of these factors interact, and to determine from a performance perspective whether a PBncf vehicle could be competitive with a PBw/cf or SB vehicle using equivalent technology and assumptions. In all cases, performance was evaluated on a relative basis for a fixed payload and mission by comparing gross and dry vehicle masses of a closed vehicle. Propellant combinations studied were LOX: LH2 propelled orbiter and booster (HH) and LOX: Kerosene booster with LOX: LH2 orbiter (KH). The study conclusions were: 1) a PBncf orbiter should be throttled as deeply as possible after launch until the staging point. 2) a detailed structural model is essential to accurate architecture analysis and evaluation. 3) a PBncf TSTO architecture is feasible for systems that stage at mach 7. 3a) HH architectures can achieve a mass growth relative to PBw/cf of < 20%. 3b) KH architectures can achieve a mass growth relative to Series Burn of < 20%. 4) center of gravity (CG) control will be a major issue for a PBncf vehicle, due to the low orbiter specific thrust to weight ratio and to the position of the orbiter required to align the nozzle heights at liftoff. 5 ) thrust to weight ratios of 1.3 at liftoff and between 1.0 and 0.9 when staging at mach 7 appear to be close to ideal for PBncf vehicles. 6) performance for all vehicles studied is better when staged at mach 7 instead of mach 5. The study showed that a Series Burn architecture has the lowest gross mass for HH cases, and has the lowest dry mass for KH cases. The potential disadvantages of SB are the required use of an air-start for the orbiter engines and potential CG control issues. A Parallel Burn with crossfeed architecture solves both these problems, but the

  3. Possible Glacial Erosion of Interior Layered Deposit Mounds in Central Candor Chasma

    NASA Astrophysics Data System (ADS)

    Chapman, M. G.; Dumke, A.; Michaels, G.; Neukum, G.

    2007-12-01

    Within Candor Chasma, there are 5 mesas or mounds (Candor and Baetis Mensae and 3 unnamed mensae to the east) of interior layered deposits (ILDs) that encircle the central Chasma low and have v- and wedge-shaped terminations that point toward this basin. Several datasets (Viking, MOLA, MOC, THEMIS, and HRSC) show features, analogous to glacial landforms, deposited on and carved into these ILD flanks and into the dark materials that embay them and also cover the chasma floor (Chapman et al., 2004, 2005). Five canyons (1 west of Candor Mensa and 4 between the five ILD mounds) are observed to terminate at the floor of central Candor Chasma. West of Candor Mensa, canyon 1 shows a pair of side-bounding ridges that may be possible lateral moraines, one on the west side of the southern mensa horn. This canyon is headed by a 3- forked (or pronged) headwall (centered at about lat 6.5° S., long 74°) that is very similar to analog glacial cirques. More erosional features can be observed up slope from this possible cirque. Canyon 2, between Candor and Baetis Mensae, is bound on the sides by possible lateral moraines and can be traced to a possible cirque on the wall between Ophir and Candor Chasmata. Just below this possible cirque (west of Baetis) the canyon contains a narrow central ridge that may be a medial moraine. Canyon 3, east of Baetis Mensa, shows numerous grooves cut into its floor and eroded, stair-stepped ridges of dark material on the canyon terminus at the central Candor Chasma floor. Analogous terrestrial terminal ridges can form as glaciers shrink and recess back from a point of maximum extent, each ridge may be a depositional end moraine that marks a hiatus in the recession process. Canyon 4, centered at about lat 6.5° S., long 71.4° and between the two unnamed ILD mounds east of Baetis Mensa, is a short hanging wall canyon again bound by sets of ridges (lateral moraines?). Canyon 5, between the easternmost ILDs of central Candor Chasma, shows 2 terraces

  4. Separation of flue-gas scrubber sludge into marketable products

    SciTech Connect

    Kawatra, S.K.; Eisele, T.C.

    1997-08-31

    A tremendous amount of wet flue-gas desulfurization scrubber sludge (estimated 20 million metric tons per year in the US) is currently being landfilled at a huge cost to utility companies. Scrubber sludge is the solid precipitate produced during desulfurization of flue-gas from burning high sulfur coal. The amount of this sludge is expected to increase in the near future due to ever increasing governmental regulation concerning the amount of sulfur emissions. Scrubber sludge is a fine, grey colored powder that contains calcium sulfite hemihydrate (CaSO{sub 3} {center_dot} 1/2H{sub 2}), calcium sulfate dihydrate (CaSO{sub 4} {center_dot} 2H{sub 2}O), limestone (CaCO{sub 3}), silicates, and iron oxides. This material can continue to be landfilled at a steadily increasing cost, or an alternative for utilizing this material can be developed. This study explores the characteristics of a naturally oxidized wet flue-gas desulfurization scrubber sludge and uses these characteristics to develop alternatives for recycling this material. In order for scrubber sludge to be used as a feed material for various markets, it was necessary to process it to meet the specifications of these markets. A physical separation process was therefore needed to separate the components of this sludge into useful products at a low cost. There are several physical separation techniques available to separate fine particulates. These techniques can be divided into four major groups: magnetic separation, electrostatic separation, physico-chemical separation, and density-based separation. The properties of this material indicated that two methods of separation were feasible: water-only cycloning (density-based separation), and froth flotation (physico-chemical separation). These processes could be used either separately, or in combination. The goal of this study was to reduce the limestone impurity in this scrubber sludge from 5.6% by weight to below 2.0% by weight. The resulting clean calcium

  5. Step-by-step thermal transformations of a new porous coordination polymer [(H{sub 2}O){sub 5}CuBa(Me{sub 2}mal){sub 2}]{sub n} (Me{sub 2}mal{sup 2-}=dimethylmalonate): Thermal degradation to barium cuprate

    SciTech Connect

    Zauzolkova, Natalya; Dobrokhotova, Zhanna; Lermontov, Anatoly; Zorina, Ekaterina; Emelina, Anna; Bukov, Mikhail; Sidorov, Aleksey; Kiskin, Mikhail; Bogomyakov, Artem; Lytvynenko, Anton; Kolotilov, Sergey; Velikodnyi, Yuriy; Kovba, Maksim

    2013-01-15

    The reactions of CuSO{sub 4}{center_dot}5H{sub 2}O, dimethylmalonic acid and Ba(OH){sub 2}{center_dot}H{sub 2}O (Cu: H{sub 2}Me{sub 2}mal: Ba=1: 2: 2) in aqueous and aqueous-ethanol solutions (H{sub 2}O: EtOH=1: 1) resulted in formation of 3D-porous coordination polymers [(H{sub 2}O){sub 3}({mu}-H{sub 2}O){sub 2}CuBa({mu}{sub 3}-Me{sub 2}mal)(Me{sub 2}mal)]{sub n} (1) and [({mu}-H{sub 2}O)CuBa({mu}{sub 3}-Me{sub 2}mal)({mu}{sub 4}-Me{sub 2}mal)]{sub n} (2), respectively. It has been shown that compound 2 was an intermediate in the thermal degradation of compound 1. Thorough studies of solid-state thermolysis of 1 and 2 allowed to detect formation of coordination polymer [CuBa({mu}{sub 4}-Me{sub 2}mal)({mu}{sub 5}-Me{sub 2}mal)]{sub n} (3), structure of which was determined by X-ray powder diffraction. It has been found that the channels in polymer 3 were accessible for guest molecules (MeOH). Theoretical estimation of methanol diffusion barrier was carried out. Complete solid-phase thermolysis of 1 and 2 leads to a mixture of BaCuO{sub 2}, BaCO{sub 3}, and CuO. Special conditions for obtaining of a crystalline phase of pure cubic BaCuO{sub 2} were determined. - Graphical abstract: Step-by-step transformation of new coordination polymer [(H{sub 2}O){sub 5}CuBa(Me{sub 2}mal){sub 2}]{sub n} to [(H{sub 2}O)CuBa(Me{sub 2}mal){sub 2}]{sub n} and [CuBa(Me{sub 2}mal){sub 2}]{sub n} were performed. Dehydration of initial compound leads to structural changes of 12-membered ring fragment. All compounds have porous structure. The final product of thermal decomposition is crystalline phase of individual cubic BaCuO{sub 2}. Highlights: Black-Right-Pointing-Pointer New 3D-polymers [(H{sub 2}O){sub 5}CuBa(Me{sub 2}mal){sub 2}]{sub n} and [(H{sub 2}O)CuBa(Me{sub 2}mal){sub 2}]{sub n} were synthesized. Black-Right-Pointing-Pointer Thermal analysis showed step-by-step transformations of [(H{sub 2}O){sub 5}CuBa(Me{sub 2}mal){sub 2}]{sub n}. Black-Right-Pointing-Pointer Crystalline

  6. SYNTHESIS OF SULFUR-BASED WATER TREATMENT AGENT FROM SULFUR DIOXIDE WASTE STREAMS

    SciTech Connect

    Robert C. Brown; Maohong Fan; Adrienne Cooper

    2004-11-01

    Absorption of sulfur dioxide from a simulated flue gas was investigated for the production of polymeric ferric sulfate (PFS), a highly effective coagulant useful in treatment of drinking water and wastewater. The reaction for PFS synthesis took place near atmospheric pressure and at temperatures of 30-80 C. SO{sub 2} removal efficiencies greater than 90% were achieved, with ferrous iron concentrations in the product less than 0.1%. A factorial analysis of the effect of temperature, oxidant dosage, SO{sub 2} concentration, and gas flow rate on SO{sub 2} removal efficiency was carried out, and statistical analyses are conducted. The solid PFS was also characterized with different methods. Characterization results have shown that PFS possesses both crystalline and non-crystalline structure. The kinetics of reactions among FeSO{sub 4} {center_dot} 7H{sub 2}O, NaHSO{sub 3} and NaClO{sub 3} was investigated. Characterizations of dry PFS synthesized from SO{sub 2} show the PFS possesses amorphous structure, which is desired for it to be a good coagulant in water and wastewater treatment. A series of lab-scale experiments were conducted to evaluate the performance of PFS synthesized from waste sulfur dioxide, ferrous sulfate and sodium chlorate. The performance assessments were based on the comparison of PFS and other conventional and new coagulants for the removal of turbidity and arsenic under different laboratory coagulant conditions. Pilot plant studies were conducted at Des Moines Water Works in Iowa and at the City of Savannah Industrial and Domestic (I&D) Water Treatment Plant in Port Wentworth, Georgia. PFS performances were compared with those of conventional coagulants. The tests in both water treatment plants have shown that PFS is, in general, comparable or better than other coagulants in removal of turbidity and organic substances. The corrosion behavior of polymeric ferric sulfate (PFS) prepared from SO{sub 2} and ferric chloride (FC) were compared. Results

  7. Redgillite, Cu[subscript 6](OH)1 0(SO[subscript 4]).2H[subscript 2]O, a new mineral from Caldbeck Fells, Cumbria, England, UK: Description and crystal structure

    SciTech Connect

    Pluth, J.J.; Steele, I.M.; Kampf, A.R.; Green, D.I.

    2008-10-03

    Redgillite, Cu{sub 6}(OH){sub 10}(SO{sub 4}) {center_dot} H{sub 2}O, space group P2{sub 1}/c, a 3.155(3) {angstrom}, b 10.441(8) {angstrom}, c 19.436(16) {angstrom}, {beta} 90.089(13){sup o}, V = 640.2(9) {angstrom}{sup 3}, Z = 2, is a new mineral from Silver Gill, Caldbeck Fells, Cumbria, England. The strongest six lines of the X-ray powder-diffraction pattern [d in {angstrom}, (I) (hkl)] are: 9.72 (90) (002), 7.11 (100) (012), 4.60 (30) (022), 4.068 (20) (023), 2.880 (30) (112,11{bar 2}), 2.318 (50) (131,13{bar 1}). It occurs as translucent to transparent grass-green bladed crystals up to 0.15 mm long with squared-off or tapering terminations; usually in radiating groups. Forms observed are {l_brace}001{r_brace} prominent, {l_brace}010{r_brace} as composite stepped faces, and {l_brace}100{r_brace} irregular. Redgillite has white streak, vitreous lustre and Mohs hardness of {approx}2. Blades are slightly flexible with irregular fracture and exhibit a perfect {l_brace}001{r_brace} cleavage and good {l_brace}100{r_brace} and {l_brace}010{r_brace} cleavages. The measured density (by sink-float) is 3.45(5) g/cm{sup 3}; the calculated density is 3.450 g/cm{sup 3}. The mineral dissolves slowly in dilute HCl. Redgillite is biaxial-negative with {alpha} = 1.693(2), {beta} = 1.721(2), {gamma} = 1.723(2), 2V = 30(2){sup o} (meas.) and 30{sup o} (calc.); dispersion is r > v, medium; pleochroism: Y blue-green > X blue-green > Z yellow-green; orientation: X c, Y = b, Z a. Electron microprobe analyses yielded CuO 68.9, SO{sub 3} 11.6, total 80.5. With water inferred from the structure analysis, the empirical formula is: Cu{sub 5.995}(OH){sub 9.991}(SO{sub 4}){sub 1.003} {center_dot} H{sub 2}O. Redgillite is typically found in thin fractures in partly oxidized sulphides where it is commonly associated with langite and more rarely with malachite, cuprite, connellite and brochantite. The name is for the Red Gill mine, from which the mineral is best known. The crystal structure of

  8. Yegorovite, Na4[Si4O8(OH)4]·7H2O, a new mineral from the Lovozero alkaline pluton, Kola Peninsula

    NASA Astrophysics Data System (ADS)

    Pekov, I. V.; Zubkova, N. V.; Chukanov, N. V.; Zadov, A. E.; Grishin, V. G.; Pushcharovsky, D. Yu.

    2010-12-01

    of two types: [NaO(OH)2(H2O)3] and [NaO(OH)(H2O)4] centered by Na. The mineral was named in memory of Yu. K. Yegorov-Tismenko (1938-2007), outstanding Russian crystallographer and crystallochemist. The type material of yegorovite has been deposited at the Fersman Mineralogical Museum of Russian Academy of Sciences, Moscow.

  9. DUSEL Facility Cooling Water Scaling Issues

    SciTech Connect

    Daily, W D

    2011-04-05

    Precipitation (crystal growth) in supersaturated solutions is governed by both kenetic and thermodynamic processes. This is an important and evolving field of research, especially for the petroleum industry. There are several types of precipitates including sulfate compounds (ie. barium sulfate) and calcium compounds (ie. calcium carbonate). The chemical makeup of the mine water has relatively large concentrations of sulfate as compared to calcium, so we may expect that sulfate type reactions. The kinetics of calcium sulfate dihydrate (CaSO4 {center_dot} 2H20, gypsum) scale formation on heat exchanger surfaces from aqueous solutions has been studied by a highly reproducible technique. It has been found that gypsum scale formation takes place directly on the surface of the heat exchanger without any bulk or spontaneous precipitation in the reaction cell. The kinetic data also indicate that the rate of scale formation is a function of surface area and the metallurgy of the heat exchanger. As we don't have detailed information about the heat exchanger, we can only infer that this will be an issue for us. Supersaturations of various compounds are affected differently by temperature, pressure and pH. Pressure has only a slight affect on the solubility, whereas temperature is a much more sensitive parameter (Figure 1). The affect of temperature is reversed for calcium carbonate and barium sulfate solubilities. As temperature increases, barium sulfate solubility concentrations increase and scaling decreases. For calcium carbonate, the scaling tendencies increase with increasing temperature. This is all relative, as the temperatures and pressures of the referenced experiments range from 122 to 356 F. Their pressures range from 200 to 4000 psi. Because the cooling water system isn't likely to see pressures above 200 psi, it's unclear if this pressure/scaling relationship will be significant or even apparent. The most common scale minerals found in the oilfield include

  10. Response of atmosphere circulation on global and regional scales to the two El Niño flavors

    NASA Astrophysics Data System (ADS)

    Zheleznova, Irina; Gushchina, Daria

    2015-04-01

    Indonesia, south to the equator prevails air descent. During El Niño Modoki anomalous air rising occurs over the central equatorial Pacific, while descending motion develop to the east (mainly in the equatorial regions of the Southern Hemisphere) and to the west (in the Northern Hemisphere). The structure of the anomalies of vertical cells outside the Pacific region differ over the Western Indian Ocean and East Africa, South America and the Caribbean. The analysis of regional circulation response to the El Niño revealed that in the Northern Hemisphere the intensity of the response is comparable for two types of El Niño, while in the Southern Hemisphere the circulation anomalies are more pronounced during the El Niño Modoki. All atmosphere centers of actions under investigation were divided into four groups according to the character of circulation response to the two types of El Niño: 1 - centers of action with similar response to both types of El Niño; 2 - centers of action with different response to canonical and Modoki El Niño; 3 - centers of action, having significant correlations with only one type of El Niño; 4 - centers of action with no significant relationships with two types of El Niño. It is suggested that the difference in weather anomalies observed during the two types of El Niño are mostly associated to the circulation anomalies in the centers of action and in the vertical cells which differs between canonical and Modoki El Niño. References: 1. Ashok K., Behera S. K., Rao S. A., Weng H., Yamagata, T. El Nino Modoki and its possible teleconnection. J. Geophys. Res. 2007, 112, C11007, doi:10.1029/2006JC003798. 2. Kug, J.S., Jin F.F. and An S.I. Two types of El Niño events:Cold tongue El Niño and warm pool El Niño. // J. Clim., 2009, vol. 22, pp. 1499-1515. 3. Mo, K. C., Interdecadal modulation of the impact of ENSO on precipitation and temperature over the United States, J. Clim., 2010, 23, 3639-3656, doi:10.1175/2010JCLI3553.1. 4. Weng H., Behera

  11. Refractory Materials for Flame Deflector Protection System Corrosion Control: Refractory Ceramics Literature Survey

    NASA Technical Reports Server (NTRS)

    Calle, Luz Marina; Hintze, Paul E.; Parlier, Christopher R.; Curran, Jerome P.; Kolody, Mark; Perusich, Stephen; Whitten, Mary C.; Trejo, David; Zidek, Jason; Sampson, Jeffrey W.; Coffman, Brekke E.

    2009-01-01

    Ceramics can be defmed as a material consisting of hard brittle properties produced from inorganic and nonmetallic minerals made by firing at high temperatures. These materials are compounds between metallic and nonmetallic elements and are either totally ionic, or predominately ionic but having some covalent character. This definition allows for a large range of materials, not all applicable to refractory applications. As this report is focused on potential ceramic materials for high temperature, aggressive exposure applications, the ceramics reviewed as part of this report will focus on refractory ceramics specifically designed and used for these applications. Ceramic materials consist of a wide variety of products. Callister (2000) 1 characterized ceramic materials into six classifications: glasses, clay products, refractories, cements, abrasives, and advanced ceramics. Figure 1 shows this classification system. This review will focus mainly on refractory ceramics and cements as in general, the other classifications are neither applicable nor economical for use in large structures such as the flame trench. Although much work has been done in advanced ceramics over the past decade or so, these materials are likely cost prohibitive and would have to be fabricated off-site, transported to the NASA facilities, and installed, which make these even less feasible. Although the authors reviewed the literature on advanced ceramic refractories 2 center dot 3 center dot 4 center dot 5 center dot 6 center dot 7 center dot 8 center dot 9 center dot 10 center dot 11 center dot 12 after the review it was concluded that these materials should not be ' the focus of this report. A review is in progress on materials and systems for prefabricated refractory ceramic panels, but this review is focusing more on typical refractory materials for prefabricated systems, which could make the system more economically feasible. Refractory ceramics are used for a wide variety of applications

  12. New images of Mercury in the 210-350°W longitude range

    NASA Astrophysics Data System (ADS)

    Ksanfomality, L. V.

    2008-09-01

    apparently similar to the structure of Caloris Planitia area, having, most likely, an impact origin, as suggested earlier [1]. The rim of Basin S has a more or less regular shape, as is seen in the image (a). The feature may be revealed both by shadows of the east rim and by albedo effects. The unsharp mask operation used in creating Fig. 1, involves a compromise choice. Therefore the actual tone, either of Basin S and of dark mare on the limb, are darker, than on Fig. 1. The sector 265-350oW of longitudes of Mercury is enriched by contrast features in comparison with the sector 210-285oW (Fig. 1b). A few large features in Fig. 1a attract the attention. On the very limb, to the south of equator, a big dark crater mare of the genuine lunar type is seen as a dark at the left, with the center near 25°S, 330°W. Its diameter is about 700 kms. This is the first detection of such a lunar type mare on Mercury. Along the limb, from North Pole up to 20°S, a line of bright craters extends. The brightest is placed in northern part of the planet, at 65°N, 330°W, approximately. The crater is small, its diameter is 90-100 kms; to the north and south sides there are two linear structures adjoining, extending for 400-500 kms. Such opposingly directed rays of debris from an impact crater are unusual; it may be a result of a low tangent trajectory of an impactor [4]. Centered approximately at 0°, 300°W there is a huge crater with the conditional nickname "Medallion". Its northern periphery is overlapped in part with the southwest extremity of Basin S. Details of the crater "Medallion" are presented in Fig. 2, in negative versions. The visibility in this version unveils petals of the "medallion" in more detail. In the center of "Medallion" there is a dark (in negative) nucleus («the central hill» in the lunar terminology), having diameter about 110 kms, surrounded with a crater bottom, diameter about 320 kms (extents are given in the meridian direction). The extensive terrace of debris