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Sample records for waxd nmr n2

  1. A new Schiff base compound N,N'-(2,2-dimetylpropane)-bis(dihydroxylacetophenone): synthesis, experimental and theoretical studies on its crystal structure, FTIR, UV-visible, 1H NMR and 13C NMR spectra.

    Science.gov (United States)

    Saheb, Vahid; Sheikhshoaie, Iran

    2011-10-15

    The Schiff base compound, N,N'-(2,2-dimetylpropane)-bis(dihydroxylacetophenone) (NDHA) is synthesized through the condensation of 2-hydroxylacetophenone and 2,2-dimethyl 1,3-amino propane in methanol at ambient temperature. The yellow crystalline precipitate is used for X-ray single-crystal determination and measuring Fourier transform infrared (FTIR), UV-visible, (1)H NMR and (13)C NMR spectra. Electronic structure calculations at the B3LYP, PBEPBE and PW91PW91 levels of theory are performed to optimize the molecular geometry and to calculate the FTIR, (1)H NMR and (13)C NMR spectra of the compound. Time-dependent density functional theory (TDDFT) method is used to calculate the UV-visible spectrum of NDHA. Vibrational frequencies are determined experimentally and compared with those obtained theoretically. Vibrational assignments and analysis of the fundamental modes of the compound are also performed. All theoretical methods can well reproduce the structure of the compound. The (1)H NMR and (13)C NMR chemical shifts calculated by all DFT methods are consistent with the experimental data. However, the NMR shielding tensors computed at the B3LYP/6-31+G(d,p) level of theory are in better agreement with experimental (1)H NMR and (13)C NMR spectra. The electronic absorption spectrum calculated at the B3LYP/6-31+G(d,p) level by using TD-DFT method is in accordance with the observed UV-visible spectrum of NDHA. In addition, some quantum descriptors of the molecule are calculated and conformational analysis is performed and the results were compared with the crystallographic data. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. NMR

    International Nuclear Information System (INIS)

    Kneeland, J.B.; Lee, B.C.P.; Whalen, J.P.; Knowles, R.J.R.; Cahill, P.T.

    1984-01-01

    Although still quite new, NMR imaging has already emerged as a safe, noninvasive, painless, and effective diagnostic modality requiring no ionizing radiation. Also, NMR appears already to have established itself as the method of choice for the examination of the brain spinal cord (excluding herniated disks). Another area in which NMR excels is in the examination of the pelvis. The use of surface coils offers the promise of visualizing structures with resolution unobtainable by any other means. In addition, NMR, with its superb visualization of vascular structures and potential ability to measure flow, may soon revolutionize the diagnosis of cardiovascular disease. Finally, NMR, through biochemically and physiologically based T/sub 1/ and T/sub 2/ indices or through spectroscopy, may provide a means of monitoring therapeutic response so as to permit tailoring of treatment to the individual patient. In short, NMR is today probably at the same stage as the x-ray was in Roentgen's day

  3. Time-Resolved WAXD and SAXS Investigations on Butyl Branched Alkane at Elevated Pressures

    NARCIS (Netherlands)

    Rastogi, A.; Hobbs, J.K.; Rastogi, S.

    2002-01-01

    The crystallization behavior and the morphological aspect of the butyl branched alkane C96H193CH(C4H9)C94H189 have been investigated using time-resolved wide-angle X-ray diffraction (WAXD) and small-angle X-ray scattering (SAXS) at atmospheric and elevated pressures. The solution crystallized sample

  4. Crystal structure, NMR study, dc-conductivity and dielectric relaxation studies of a new compound [C2H10N2]Cd(SCN2Cl2

    Directory of Open Access Journals (Sweden)

    Gargouri M.

    2012-06-01

    Full Text Available The crystal structure, the solid NMR spectroscopy and the complex impedance study have been carried out on [C2H10N2]CdCl2(SCN2. Characterization by single crystal X-ray crystallography shows that the cadmium atoms have à 2N2S2Cl hexa-coordination sphere, exhibiting pseudo-octahedral geometry. The cadmium atoms are bridged by two thiocyanate ions generating 1-D polymeric-chains. These chains are themselves interconnected by means of N-H…Cl(NCS hydrogen bonds originating from the organic cation [(NH32(CH22]2+. 111Cd isotropic chemical shifts span a range of 268ppm. The cadmium atom exhibits multiplets that result from 111Cd-14N spin-spin coupling. Examination of 111Cd and 13C MAS line shapes shows direct measurement of the indirect spin-spin coupling constant 2J(111Cd, 14N = 105Hz and the dipolar coupling constant of 1381Hz . Impedance spectroscopy measurements of [C2H10N2]CdCl2(SCN2 have been studied from 209Hz to 5 MHz over the temperature range 300-370 K. The Cole-Cole (Z” versus Z’ plots are fitted to two equivalent circuits models. The formalism of complex permittivity and impedance were employed to analyze the experimental data. The dc conductivity follows the Arrhenius relation with an activation energy Ea = 0.54 (3 eV.

  5. Synchrotron SAXS/WAXD and rheological studies of clay suspensions in silicone fluid.

    Science.gov (United States)

    Zhang, Li-Ming; Jahns, Christopher; Hsiao, Benjamin S; Chu, Benjamin

    2003-10-15

    Suspensions of two commercial smectite clays, montmorillonite KSF and montmorillonite K10, in a low-viscosity silicone oil (Dow Corning 245 Fluid) were studied by simultaneous synchrotron small-angle X-ray scattering (SAXS)/wide-angle X-ray diffraction (WAXD) techniques and rheological measurements. In the 0.5% (w/v) KSF clay suspension and two K10 clay suspensions (0.5% and 1.0%), WAXD profiles below 2theta=10.0 degrees did not display any characteristic reflection peaks associated with the chosen montmorillonite clays, while corresponding SAXS profiles exhibited distinct scattering maxima, indicating that both clays were delaminated by the silicone oil. In spite of the large increase in viscosity, the clay suspensions exhibited no gel characteristics. Dynamic rheological experiments indicated that the clay/silicone oil suspensions exhibited the behavior of viscoelasticity, which could be influenced by the type and the concentration of the clay. For the K10 clay suspensions, the frequency-dependent loss modulus (G") was greater in magnitude than the storage modulus (G') in the concentration range from 0.5 to 12.0%. The increase in the clay concentration shifted the crossover point between G' and G" into the accessible frequency range, indicating that the system became more elastic. In contrast, the KSF clay suspension exhibited lower G' and G" values, indicating a weaker viscoelastic response. The larger viscoelasticity response in the K10 clay suspension may be due to the acid treatment generating a higher concentration of silanol groups on the clay surface.

  6. NMR solution structure of an N2-guanine DNA adduct derived from the potent tumorigen dibenzo[a,l]pyrene: Intercalation from the minor groove with ruptured Watson-Crick base pairing

    Science.gov (United States)

    Tang, Yijin; Liu, Zhi; Ding, Shuang; Lin, Chin H.; Cai, Yuqin; Rodriguez, Fabian A.; Sayer, Jane M.; Jerina, Donald M.; Amin, Shantu; Broyde, Suse; Geacintov, Nicholas E.

    2012-01-01

    The most potent tumorigen identified among the polycyclic aromatic hydrocarbons (PAH) is the non-planar fjord region dibenzo[a,l]pyrene (DB[a,l]P). It is metabolically activated in vivo through the widely-studied diol epoxide (DE) pathway to form covalent adducts with DNA bases, predominantly guanine and adenine. The (+)-11S,12R,13R,14S DE enantiomer forms adducts via its C14-position with the exocyclic amino group of guanine. Here, we present the first NMR solution structure of a DB[a,l]P-derived adduct, the 14R (+)-trans-anti-DB[a,l]P–N2-dG (DB[a,l]P-dG) lesion in double-stranded DNA. In contrast to the stereochemically identical benzo[a]pyrene-derived N2-dG adduct (B[a]P-dG) in which the B[a]P rings reside in the B-DNA minor groove on the 3’-side of the modifed deoxyguanosine, in the DB[a,l]P-derived adduct the DB[a,l]P rings intercalate into the duplex on the 3’-side of the modified base from the sterically crowded minor groove. Watson-Crick base pairing of the modified guanine with the partner cytosine is broken, but these bases retain some stacking with the bulky DB[a,l]P ring system. This new theme in PAH DE - DNA adduct conformation differs from: (1) the classical intercalation motif where Watson-Crick base-pairing is intact at the lesion site, and (2) the base-displaced intercalation motif in which the damaged base and its partner are extruded from the helix . The structural considerations that lead to the intercalated conformation of the DB[a,l]P-dG lesion in contrast to the minor groove alignment of the B[a]P-dG adduct, and the implications of the DB[a,l]P-dG conformational motif for the recognition of such DNA lesions by the human nucleotide excision repair apparatus, are discussed. PMID:23121427

  7. New Insights into Lamellar Structure Development and SAXS/WAXD Sequence Appearance During Uniaxial Stretching of Amorphous Poly(ethylene terephthalate) Above Glass Transition Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Kawakami,D.; Burger, C.; Ran, S.; Avila-Orta, C.; Sics, I.; Chu, B.; Chiao, S.; Hsiao, B.; Kikutani, T.

    2008-01-01

    An in situ study of structure formation in amorphous poly(ethylene terephthalate) (PET) during uniaxial stretching at a temperature 30 C above glass transition temperature was carried out using synchrotron small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) techniques. Three major deformation-induced structure transitions were confirmed. (1) At small strains, the applied load increased initially but leveled off afterward. Sporadic isotropic crystallization without preferred orientation was observed by WAXD, where no hierarchical structure was seen by SAXS. (2) At intermediate strains, strain hardening took place. Although WAXD showed persistent progression of isotropic crystallization, SAXS indicated formation of a layered structure as well as a fibrillar domain in large scale. This behavior is not consistent with the mechanisms for shish-kebab or spinodal-assisted structure formation. Instead, it can be explained by flow-induced demixing of crystal and amorphous phases through layerlike flocking motion perpendicular to the stretching direction. (3) At high strains, the ratio between the applied load and strain was about constant. In this stage, crystal reorientation and lateral crystal growth took place. The corresponding structure changes could be categorized into three subregions. In the first region, the (010) crystalline plane began to orient. In the second region, the (100) crystalline plane began to orient. In the last region, the structure change became stable and the sample eventually broke apart.

  8. Noncompact N=2 supergravity

    International Nuclear Information System (INIS)

    Wit, B. de; Lauwers, P.G.; Philippe, R.; Van Proeyen, A.

    1983-10-01

    A massive spin-1 multiplet with central charge is coupled to N=2 supergravity. Compared to conventional gauge fields the anomalous magnetic moment of the spin-1 particles is of opposite sign. The construction of this theory is based on an N=2 supersymmetric gauge theory associated with the noncompact group SO(2,1). As a byproduct we present a convenient expression for the N=2 Einstein-Yang-Mills lagrangian. (Auth.)

  9. Time domain NMR evaluation of poly(vinyl alcohol) xerogels

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Elton Jorge da Rocha; Cavalcante, Maxwell de Paula; Tavares, Maria Ines Bruno, E-mail: mibt@ima.ufrj.br [Universidade Federal do Rio de Janeiro (IMA/UFRJ), Rio de Janeiro, RJ (Brazil). Centro de Tecnologia. Instituto de Macromoleculas Professora Eloisa Mano

    2016-05-15

    Poly(vinyl alcohol) (PVA)-based chemically cross-linked xerogels, both neat and loaded with nanoparticulate hydrophilic silica (SiO{sub 2}), were obtained and characterized mainly through time domain NMR experiments (TD-NMR). Fourier-transform infrared (FT-IR) and wide angle X-ray diffraction (WAXD) analyses were employed as secondary methods. TD-NMR, through the interpretation of the spin-lattice relaxation constant values and related information, showed both cross-linking and nanoparticle influences on PVA matrix. SiO{sub 2} does not interact chemically with the PVA chains, but has effect on its molecular mobility, as investigated via TD-NMR. Apparent energy of activation, spin-lattice time constant and size of spin domains in the sample have almost linear dependence with the degree of cross-linking of the PVA and are affected by the addition of SiO{sub 2}. These three parameters were derived from a single set of TD-NMR experiments, which demonstrates the versatility of the technique for characterization of inorganic-organic hybrid xerogels, an important class of materials. (author)

  10. Syntheses and multi-NMR study of fac- and mer-OsO(3)F(2)(NCCH(3)) and the X-ray crystal structure (n = 2) and Raman spectrum (n = 0) of fac-OsO(3)F(2)(NCCH(3)).nCH(3)CN.

    Science.gov (United States)

    Hughes, Michael J; Gerken, Michael; Mercier, Hélène P A; Schrobilgen, Gary J

    2010-06-07

    Dissolution of the infinite chain polymer, (OsO(3)F(2))(infinity), in CH(3)CN solvent at -40 degrees C followed by solvent removal under vacuum at -40 degrees C yielded fac-OsO(3)F(2)(NCCH(3)).nCH(3)CN (n >/= 2). Continued pumping at -40 degrees C with removal of uncoordinated CH(3)CN yielded fac-OsO(3)F(2)(NCCH(3)). Both fac-OsO(3)F(2)(NCCH(3)).nCH(3)CN and fac-OsO(3)F(2)(NCCH(3)) are yellow-brown solids and were characterized by low-temperature (-150 degrees C) Raman spectroscopy. The crystal structure (-173 degrees C) of fac-OsO(3)F(2)(NCCH(3)).2CH(3)CN consists of two co-crystallized CH(3)CN molecules and a pseudo-octahedral OsO(3)F(2).NCCH(3) molecule in which three oxygen atoms are in a facial arrangement and CH(3)CN is coordinated trans to an oxygen atom in an end-on fashion. The Os---N bond length (2.205(3) A) is among the shortest M---N adduct bonds observed for a d(0) transition metal oxide fluoride. The (19)F NMR spectrum of (OsO(3)F(2))(infinity) in CH(3)CN solvent (-40 degrees C) is a singlet (-99.6 ppm) corresponding to fac-OsO(3)F(2)(NCCH(3)). The (1)H, (15)N, (13)C, and (19)F NMR spectra of (15)N-enriched OsO(3)F(2)(NCCH(3)) were recorded in SO(2)ClF solvent (-84 degrees C). Nitrogen-15 enrichment resulted in splitting of the (19)F resonance of fac-OsO(3)F(2)((15)NCCH(3)) into a doublet ((2)J((15)N-(19)F), 21 Hz). In addition, a doublet of doublets ((2)J((19)F(ax)-(19)F(eq)), 134 Hz; (2)J((15)N-(19)F(eq)), 18 Hz) and a doublet ((2)J((19)F(ax)-(19)F(eq)), 134 Hz) were observed in the (19)F NMR spectrum that have been assigned to mer-OsO(3)F(2)((15)NCCH(3)); however, coupling of (15)N to the axial fluorine-on-osmium environment could not be resolved. The nitrogen atom of CH(3)CN is coordinated trans to a fluorine ligand in the mer-isomer. Quantum-chemical calculations at the SVWN and B3LYP levels of theory were used to calculate the energy-minimized gas-phase geometries, vibrational frequencies of fac- and mer-OsO(3)F(2)(NCCH(3)) and of CH(3)CN. The

  11. Nonabelian N=2 superstrings

    International Nuclear Information System (INIS)

    Isaev, A.P.; Ivanov, E.A.

    1990-04-01

    The Green-Schwarz covariant N=2 superstring action can be consistently deduced as the action of the Wess-Zumino-Witten (WZW) sigma model defined on the direct product of two N=1, D=10 Poincare supertranslation groups. Generalizing this result, we construct new WZW sigma models on the supergroups with a nonabelian even part and interpret them as models of superstrings moving on the supergroup manifolds. We show that these models are completely integrable and in some special cases possess fermionic k-symmetry. (author). 20 refs

  12. Crystal structure, quantum mechanical investigation, IR and NMR spectroscopy of two new organic perchlorates: (C6H18N3)·(ClO4)3H2O (I) and (C9H11N2)·ClO4(II)

    Science.gov (United States)

    Bayar, I.; Khedhiri, L.; Soudani, S.; Lefebvre, F.; Ferretti, V.; Ben Nasr, C.

    2018-06-01

    The reaction of perchloric acid with 1-(2-aminoethyl)piperazine or 5,6-dimethyl-benzimidazole results in the formation of 1-(2-amonioethyl)piperazine-1,4-dium triperchlorate hydrate (C6H18N3)·(ClO4)3·H2O (I) or 5,6-dimethyl-benzylimidazolium perchlorate (C9H11N2)·ClO4(II). Both compounds were fully structurally characterized including single crystal X-ray diffraction analysis. Compound (I) crystallizes in the centrosymmetric triclinic space group P 1 bar with the lattice parameters a = 7.455 (2), b = 10.462 (2), c = 10.824 (2) Å, α = 80.832 (2), β = 88.243 (2), γ = 88.160 (2) °, Z = 2 and V = 832.77 (3) Å3. Compound (II) has been found to belong to the P21/c space group of the monoclinic system, with a = 7.590 (3), b = 9.266 (3), c = 16.503 (6) Å, β = 107.38 (2) °, V = 1107.69 (7) Å3 and Z = 4. The structures of (I) and (II) consist of slightly distorted [ClO4]- tetrahedra anions and 1-(2-amonioethyl)piperazine-1,4-dium trication (I) or 5,6-dimethyl-benzylimidazolium cations (II) and additionally a lattice water in (I). The crystal structures of (I) and (II) exhibit complex three-dimensional networks of H-bonds connecting all their components. In the atomic arrangement of (I), the ClO4- anions form corrugated chains, while in (II) the atomic arrangement exhibits wide pseudo-hexagonal channels of ClO4 tetrahedra including the organic entities. The lattice water serves as a link between pairs of cations and pairs of anions via several Osbnd H⋯O and N-H⋯O interactions in compound (I). The vibrational absorption bands were identified by infrared spectroscopy. These compounds were also investigated by solid-state 13C, 35Cl and 15N NMR spectroscopy. DFT calculations allowed the attribution of the IR and NMR bands. Intermolecular interactions were investigated by Hirshfeld surfaces. Electronic properties such as HOMO and LUMO energies were derived.

  13. NMR imaging

    International Nuclear Information System (INIS)

    Andrew, E.R.

    1983-01-01

    Since hydrogen is the most abundant element in all living organisms, proton NMR lends itself well as a method of investigation in biology and medicine. NMR imaging has some special advantages as a diagnostic tool: no ionizing radiation is used, it is noninvasive; it provides a safer means of imaging than the use of x-rays, gamma rays, positrons, or heavy ions. In contrast with ultrasound, the radiation penetrates the bony structures without attenuation. In additional to morphological information, NMR imaging provides additional diagnostic insights through relaxation parameters, which are not available from other imaging methods. In the decade since the first primitive NMR images were obtained, the quality of images now obtained approaches those from CT x-ray scanners. Prototype instruments are being constructed for clinical evaluation and the first whole-body scanners are beginning to appear on the market at costs comparable to CT scanners. Primary differences in equipment for conventional NMR and NMR imaging are the much larger aperture magnets that are required for the examination of human subjects and the addition of coils to generate field gradients and facilities for manipulating the gradients. Early results from clinical trials in many parts of the world are encouraging, and in a few years, the usefuleness of this modality of medical imaging to the medical profession in diagnosis and treatment of disease will be defined. 10 figures

  14. Compact NMR

    Energy Technology Data Exchange (ETDEWEB)

    Bluemich, Bernhard; Haber-Pohlmeier, Sabina; Zia, Wasif [RWTH Aachen Univ. (Germany). Inst. fuer Technische und Makromolekulare Chemie (ITMC)

    2014-06-01

    Nuclear Magnetic Resonance (NMR) spectroscopy is the most popular method for chemists to analyze molecular structures, while Magnetic Resonance Imaging (MRI) is a non-invasive diagnostic tool for medical doctors that provides high-contrast images of biological tissue. In both applications, the sample (or patient) is positioned inside a large, superconducting magnet to magnetize the atomic nuclei. Interrogating radio-frequency pulses result in frequency spectra that provide the chemist with molecular information, the medical doctor with anatomic images, and materials scientist with NMR relaxation parameters. Recent advances in magnet technology have led to a variety of small permanent magnets to allow compact and low-cost instruments. The goal of this book is to provide an introduction to the practical use of compact NMR at a level nearly as basic as the operation of a smart phone.

  15. Simultaneous Synchrotron WAXD and Fast Scanning (Chip) Calorimetry: On the (Isothermal) Crystallization of HDPE and PA11 at High Supercoolings and Cooling Rates up to 200 °C s(-1).

    Science.gov (United States)

    Baeten, Dorien; Mathot, Vincent B F; Pijpers, Thijs F J; Verkinderen, Olivier; Portale, Giuseppe; Van Puyvelde, Peter; Goderis, Bart

    2015-06-01

    An experimental setup, making use of a Flash DSC 1 prototype, is presented in which materials can be studied simultaneously by fast scanning calorimetry (FSC) and synchrotron wide angle X-ray diffraction (WAXD). Accumulation of multiple, identical measurements results in high quality, millisecond WAXD patterns. Patterns at every degree during the crystallization and melting of high density polyethylene at FSC typical scanning rates from 20 up to 200 °C s(-1) are discussed in terms of the temperature and scanning rate dependent material crystallinities and crystal densities. Interestingly, the combined approach reveals FSC thermal lag issues, for which can be corrected. For polyamide 11, isothermal solidification at high supercooling yields a mesomorphic phase in less than a second, whereas at very low supercooling crystals are obtained. At intermediate supercooling, mixtures of mesomorphic and crystalline material are generated at a ratio proportional to the supercooling. This ratio is constant over the isothermal solidification time. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Development of synchrotron DSC/WAXD/SAXS simultaneous measurement system for polymeric materials at the BL40B2 in SPring-8 and its application to the study of crystal phase transitions of fluorine polymers

    International Nuclear Information System (INIS)

    Masunaga, Hiroyasu; Sasaki, Sono; Takata, Masaki; Inoue, Katsuaki; Ohta, Noboru; Yagi, Naoto; Tashiro, Kohji; Hanesaka, Makoto

    2007-01-01

    A new system of rapidly-scanning DSC/WAXD/SAXS simultaneous measurements has been successfully developed at the BL40B2 in SPring-8, Japan. The combination of the ultra-bright and highly-directional X-ray beams with the highly-sensitive two-dimensional (2D) detectors such as an imaging plate (IP), a CCD detector and a flat panel (FP) detector has made it possible to perform the rapidly-scanning time-resolved measurements of WAXD and SAXS for the polymeric materials subjected to the various kinds of external field like temperature, tensile force, magnetic field, hydrostatic pressure, and so on. The experimental data about the phase transitions of vinylidene fluoride-trifluoroethylene copolymer with VDF 82 mol% content and poly(vinylidene fluoride) form I have been presented as actual examples, where the phase transitions of the polar crystal consisting of planar-zigzag chains to the gauche-type high-temperature phase have been confirmed definitely and the remarkable change in lamellar stacking structure could be detected in the temperature region immediately below the melting point. (author)

  17. NMR imaging

    International Nuclear Information System (INIS)

    Ouchi, Toshihiro; Steiner, R.E.

    1984-01-01

    Three epidermoid and two dermoid tumours, pathologically proven, were examined by NMR and CT scans. Although most brain tumours have a low signal with a long T 1 , a dermoid cyst and one of the two components of the other dermoid tumour had a high signal and therefore a short T 1 . All three epidermoid tumours had a low signal and a long T 1 . Because of the high level contrast between some of the tumours and cerebrospinal fluid, NMR is helpful to detect the lesion. Neither of the liquid fluid levels in the tumour cysts or floating fat in the subarachnoid space was recognized in one patients, but the fine leakage of the content from the epidermoid cyst into the lateral ventricle was detected on a saturation recovery 1000 image in one case. (author)

  18. New nilpotent N =2 superfields

    Science.gov (United States)

    Kuzenko, Sergei M.; Tartaglino-Mazzucchelli, Gabriele

    2018-01-01

    We propose new off-shell models for spontaneously broken local N =2 supersymmetry, in which the supergravity multiplet couples to nilpotent Goldstino superfields that contain either a gauge one-form or a gauge two-form in addition to spin-1 /2 Goldstone fermions and auxiliary fields. In the case of N =2 Poincaré supersymmetry, we elaborate on the concept of twisted chiral superfields and present a nilpotent N =2 superfield that underlies the cubic nilpotency conditions given in J. High Energy Phys. 08 (2017) 109., 10.1007/JHEP08(2017)109 in terms of constrained N =1 superfields.

  19. NMR spectroscopy

    International Nuclear Information System (INIS)

    Gruenert, J.

    1989-01-01

    The book reviews the applications of NMR-spectroscopy in medicine and biology. The first chapter of about 40 pages summarizes the history of development and explains the chemical and physical fundamentals of this new and non-invasive method in an easily comprehensible manner. The other chapters summarize diagnostic results obtained with this method in organs and tissues, so that the reader will find a systematic overview of the available findings obtained in the various organ systems. It must be noted, however, that ongoing research work and new insight quite naturally will necessitate corrections to be done, as is the case here with some biochemical interpretations which would need adjustment to latest research results. NMR-spectroscopy is able to measure very fine energy differences on the molecular level, and thus offers insight into metabolic processes, with the advantage that there is no need of applying ionizing radiation in order to qualitatively or quantitatively analyse the metabolic processes in the various organ systems. (orig./DG) With 40 figs., 4 tabs [de

  20. N-(2-Chlorophenyl-2-methylbenzamide

    Directory of Open Access Journals (Sweden)

    B. Thimme Gowda

    2008-08-01

    Full Text Available In the structure of the title compound (N2CP2MBA, C14H12ClNO, the conformations of the N—H and C=O bonds are trans to each other. Furthermore, the conformation of the N—H bond is syn to the ortho-chloro group in the aniline ring and the C=O bond is syn to the ortho-methyl substituent in the benzoyl ring, similar to what is observed in 2-chloro-N-(2-chlorophenylbenzamide and 2-methyl-N-phenylbenzamide. The amide group makes almost the same dihedral angles of 41.2 (14 and 42.2 (13° with the aniline and benzoyl rings, respectively, while the dihedral angle between the benzoyl and aniline rings is only 7.4 (3°. The molecules in N2CP2MBA are packed into chains through N—H...O hydrogen bonds.

  1. The N=2 superconformal bootstrap

    Energy Technology Data Exchange (ETDEWEB)

    Beem, Christopher [Institute for Advanced Study, Einstein Drive,Princeton, NJ 08540 (United States); Lemos, Madalena [C. N. Yang Institute for Theoretical Physics, Stony Brook University,Stony Brook, NY 11794-3840 (United States); Liendo, Pedro [IMIP, Humboldt-Universität zu Berlin, IRIS Adlershof,Zum Großen Windkanal 6, 12489 Berlin (Germany); Rastelli, Leonardo [C. N. Yang Institute for Theoretical Physics, Stony Brook University,Stony Brook, NY 11794-3840 (United States); Rees, Balt C. van [Theory Group, Physics Department, CERN,CH-1211 Geneva 23 (Switzerland)

    2016-03-29

    In this work we initiate the conformal bootstrap program for N=2 superconformal field theories in four dimensions. We promote an abstract operator-algebraic viewpoint in order to unify the description of Lagrangian and non-Lagrangian theories, and formulate various conjectures concerning the landscape of theories. We analyze in detail the four-point functions of flavor symmetry current multiplets and of N=2 chiral operators. For both correlation functions we review the solution of the superconformal Ward identities and describe their superconformal block decompositions. This provides the foundation for an extensive numerical analysis discussed in the second half of the paper. We find a large number of constraints for operator dimensions, OPE coefficients, and central charges that must hold for any N=2 superconformal field theory.

  2. Electron correlation effects on the N2--N2 interaction

    International Nuclear Information System (INIS)

    Hay, P.J.; Pack, R.T.; Martin, R.L.

    1984-01-01

    Ab initio self-consistent field, configuration interaction, and many-body perturbation theory methods are used to calculate the intermolecular potential between two nitrogen molecules. The emphasis is placed on the repulsive region important at the temperatures and pressures encountered in detonations. In addition, electron gas calculations are employed to fit and extend the ab initio data. We also generate effective spherical potentials which fit dilute gas virial, viscosity, and differential scattering data while being constrained by Hugoniot or ab initio data in the repulsive region. Finally, we discuss the roles of electron correlation and of many-body effects on the N 2 --N 2 interaction. Comparisons are also made to the Ar 2 potential where similar ab initio calculations are compared to an accurate empirical potential

  3. Twisting the N=2 string

    International Nuclear Information System (INIS)

    Ketov, S.V.; Lechtenfeld, O.; Parkes, A.J.

    1993-12-01

    The most general homogeneous monodromy conditions in N= 2 string theory are classified in terms of the conjugacy classes of the global symmetry group U(1, 1) x Z 2 . For classes which generate a discrete subgroup Γ, the corresponding target space backgrounds C 1,1 /Γ include half spaces, complex orbifolds and tori. We propose a generalization of the intercept formula to matrix-valued twists, and find massless physical states in a number of twisted cases. In particular, the sixteen Z 2 -twisted sectors of the N = 2 string are investigated, and the corresponding ground states are identified via bosonization and BRST cohomology. We find enough room for an extended multiplet of 'spacetime' supersymmetry, with the number of supersymmetries being dependent on global 'spacetime' topology. Unfortunately, world-sheet locality for the chiral vertex operators does not permit interactions for the massless 'spacetime' fermions; however possibly, an asymmetric GSO projection could evade this problem. (orig.)

  4. Bootstrapping N=2 chiral correlators

    Science.gov (United States)

    Lemos, Madalena; Liendo, Pedro

    2016-01-01

    We apply the numerical bootstrap program to chiral operators in four-dimensional N=2 SCFTs. In the first part of this work we study four-point functions in which all fields have the same conformal dimension. We give special emphasis to bootstrapping a specific theory: the simplest Argyres-Douglas fixed point with no flavor symmetry. In the second part we generalize our setup and consider correlators of fields with unequal dimension. This is an example of a mixed correlator and allows us to probe new regions in the parameter space of N=2 SCFTs. In particular, our results put constraints on relations in the Coulomb branch chiral ring and on the curvature of the Zamolodchikov metric.

  5. Bootstrapping N=2 chiral correlators

    Energy Technology Data Exchange (ETDEWEB)

    Lemos, Madalena [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Liendo, Pedro [Humboldt-Univ. Berlin (Germany). IMIP

    2015-12-15

    We apply the numerical bootstrap program to chiral operators in four-dimensional N=2 SCFTs. In the first part of this work we study four-point functions in which all fields have the same conformal dimension. We give special emphasis to bootstrapping a specific theory: the simplest Argyres-Douglas fixed point with no flavor symmetry. In the second part we generalize our setup and consider correlators of fields with unequal dimension. This is an example of a mixed correlator and allows us to probe new regions in the parameter space of N=2 SCFTs. In particular, our results put constraints on relations in the Coulomb branch chiral ring and on the curvature of the Zamolodchikov metric.

  6. Bootstrapping N=2 chiral correlators

    Energy Technology Data Exchange (ETDEWEB)

    Lemos, Madalena [DESY Hamburg, Theory Group,Notkestrasse 85, D-22607 Hamburg (Germany); Liendo, Pedro [IMIP, Humboldt-Universität zu Berlin, IRIS Adlershof,Zum Großen Windkanal 6, 12489 Berlin (Germany)

    2016-01-07

    We apply the numerical bootstrap program to chiral operators in four-dimensional N=2 SCFTs. In the first part of this work we study four-point functions in which all fields have the same conformal dimension. We give special emphasis to bootstrapping a specific theory: the simplest Argyres-Douglas fixed point with no flavor symmetry. In the second part we generalize our setup and consider correlators of fields with unequal dimension. This is an example of a mixed correlator and allows us to probe new regions in the parameter space of N=2 SCFTs. In particular, our results put constraints on relations in the Coulomb branch chiral ring and on the curvature of the Zamolodchikov metric.

  7. Potentials in N=2 supergravity

    International Nuclear Information System (INIS)

    Zinov'ev, Yu.M.

    1985-01-01

    The potentials and Yukava interactions, that arise while introducing a gauge interaction of vector and scalar multiplets in N=2 supergravity are presented, in this the gauge group may be either compact or noncompact. The scalar multiplets geometry corresponds to nonlinear σ, models of the form Sp(2,2n)/Sp(2)xSp(2n), SU(2,n)/SU(2)SU(n)xU(1) and O(4,n)/O(4)xO(n)

  8. First detection of lamella-gyroid-cylinder phase transition of neat polyethylene-poly(ethylene oxide) diblock copolymers on the basis of synchrotron WAXD/SAXS and infrared/Raman spectral measurements

    International Nuclear Information System (INIS)

    Weiyu, Cao; Tashiro, Kohji; Hanesaka, Makoto; Takeda, Shinichi; Masunaga, Hiroyasu; Sasaki, Sono; Takata, Masaki

    2009-01-01

    The phase transition behaviour of polyethylene-b-poly(ethylene oxide) (PE-b-PEO) diblock copolymer with relatively short chain lengths has been studied on the basis of temperature dependent infrared and Raman spectral measurements and synchrotron WAXD/SAXS simultaneous measurements, from which the concrete structural changes were deduced successfully from the various levels of molecular chain conformation, chain packing mode and higher-order structure. The higher-order structure has been found to transform between lamella, perforated lamella, gyroid, cylinder and sphere structures. The inner structural changes occurring in the polyethylene and poly(ethylene oxide) parts have been related with these morphological changes. The morphological transition from lamella to gyroid occurs with keeping the crystalline state of polyethylene parts. This apparently curious transition can be interpreted reasonably by assuming the thermally-activated chain motion in the crystal lattice, which may play an important role as a trigger to induce the morphological change from lamella to gyroid. This idea was supported by the measurement of half-width of Raman anti-symmetric CH 2 stretching band sensitive to the thermal mobility of alkyl chains.

  9. Microelectronic systems N2 checkbook

    CERN Document Server

    Vears, R E

    2013-01-01

    Microelectronic Systems N2 Checkbook provides coverage of the Business and Technician Education Council level NII unit in Microelectronic Systems. However, it can be regarded as a textbook in microelectronic systems for a much wider range of studies. The aim of this book is to provide a foundation in microelectronic systems hardware and software techniques. Each topic considered in the text is presented in a way that assumes in the reader only the knowledge attained in BTEC Information Technology Studies F, Engineering Fundamentals F, or equivalent. This book concentrates on the highly popular

  10. Softly broken N=2 QCD

    CERN Document Server

    Alvarez-Gaumé, Luís; Kounnas, Costas; Marino, M; Alvarez-Gaume, Luis; Distler, Jacques; Kounnas, Costas; Marino, Marcos

    1996-01-01

    We analyze the possible soft breaking of N=2 supersymmetric Yang-Mills theory with and without matter flavour preserving the analyticity properties of the Seiberg-Witten solution. For small supersymmetry breaking parameter with respect to the dynamical scale of the theory we obtain an exact expression for the effective potential. We describe in detail the onset of the confinement transition and some of the patterns of chiral symmetry breaking. If we extrapolate the results to the limit where supersymmetry decouples, we obtain hints indicating that perhaps a description of the QCD vacuum will require the use of Lagrangians containing simultaneously mutually non-local degrees of freedom (monopoles and dyons).

  11. Thermodynamic stability and guest distribution of CH4/N2/CO2 mixed hydrates for methane hydrate production using N2/CO2 injection

    International Nuclear Information System (INIS)

    Lim, Dongwook; Ro, Hyeyoon; Seo, Yongwon; Seo, Young-ju; Lee, Joo Yong; Kim, Se-Joon; Lee, Jaehyoung; Lee, Huen

    2017-01-01

    Highlights: • We examine the thermodynamic stability and guest distribution of CH 4 /N 2 /CO 2 mixed hydrates. • Phase equilibria of the CH 4 /N 2 /CO 2 mixed hydrates were measured to determine the thermodynamic stability. • The N 2 /CO 2 ratio of the hydrate phase is almost constant despite the enrichment of CO 2 in the hydrate phase. • 13 C NMR results indicate the preferential occupation of N 2 and CO 2 in the small and large cages of sI hydrates, respectively. - Abstract: In this study, thermodynamic stability and cage occupation behavior in the CH 4 – CO 2 replacement, which occurs in natural gas hydrate reservoirs by injecting flue gas, were investigated with a primary focus on phase equilibria and composition analysis. The phase equilibria of CH 4 /N 2 /CO 2 mixed hydrates with various compositions were measured to determine the thermodynamic stability of gas hydrate deposits replaced by N 2 /CO 2 gas mixtures. The fractional experimental pressure differences (Δp/p) with respect to the CSMGem predictions were found to range from −0.11 to −0.02. The composition analysis for various feed gas mixtures with a fixed N 2 /CO 2 ratio (4.0) shows that CO 2 is enriched in the hydrate phase, and the N 2 /CO 2 ratio in the hydrate phase is independent of the feed CH 4 fractions. Moreover, 13 C NMR measurements indicate that N 2 molecules preferentially occupy the small 5 12 cages of sI hydrates while the CO 2 molecules preferentially occupy the large 5 12 6 2 cages, resulting in an almost constant area ratio of CH 4 molecules in the large to small cages of the CH 4 /N 2 /CO 2 mixed hydrates. The overall experimental results provide a better understanding of stability conditions and guest distributions in natural gas hydrate deposits during CH 4 – flue gas replacement.

  12. NMR of lignins

    Science.gov (United States)

    John Ralph; Larry L. Landucci

    2010-01-01

    This chapter will consider the basic aspects and findings of several forms of NMR spectroscopy, including separate discussions of proton, carbon, heteronuclear, and multidimensional NMR. Enhanced focus will be on 13C NMR, because of its qualitative and quantitative importance, followed by NMR’s contributions to our understanding of lignin...

  13. N=2 extended supersymmetric GUTs

    International Nuclear Information System (INIS)

    Fayet, P.

    1984-01-01

    We construct N = 2 extended SUSY GUTs which provide a general association between massive spin-1 gauge bosons, spin-1/2 inos and spin-0 Higgs bosons. The corresponding gauge hypermultiplets are of four different types, while leptons and quarks are associated with mirror and spin-0 partners. The anticommutators of the two supersymmetry generators provide two spin-0 symmetry generators Zsub(s) and Zsub(p), which do not commute. Their field-independent parts and do commute, however, and appear as central charges in the symmetry algebra of the spontaneously broken gauge theory. These central charges and are linear combinations of global symmetry generators with grand unification generators such as the weak hypercharge (but not the electrical charge). They survive the electroweak symmetry breaking. They do not vanish for massive gauge hypermultiplets of types II and III, which verify M 2 = 2 + 2 > 0 and M 2 > 2 + 2 > 0, respectively. The formula M 2 approx.= 2 + 2 determines the mass spectrum on the grand unification scale, up to electroweak corrections. Finally, we indicate how our mass relations can be interpreted in a 5- or 6-dimensional formalism, the central charges appearing as the extra components of the covariant momentum along the compact fifth or sixth dimensions; and how to evaluate the grand unification mass msub(x) in terms of the lengths of the latter (msub(x)approx.=(h/2π)/Lsub(5(6))c). (orig./HSI)

  14. Local supertwistors and N=2 conformal supergravity

    International Nuclear Information System (INIS)

    Merkulov, S.A.

    1989-01-01

    N = 2 sypersymmetric extension of the local twistor theory is formulated. A supertwistor superconnection determined by the superconformal structure of the base superspace is introduced on the bundle of N = 2 local supertwistors. It is proved that the Yang - Mills equations for this superconnection coincide exactly with the Bach equations describing the dynamics of N 2 conformal supergravity

  15. NMR-CT scanner

    International Nuclear Information System (INIS)

    Kose, Katsumi; Sato, Kozo; Sugimoto, Hiroshi; Sato, Masataka.

    1983-01-01

    A brief explanation is made on the imaging methods for a practical diagnostic NMR-CT scanner : A whole-body NMR-CT scanner utilizing a resistive magnet has been developed by Toshiba in cooperation with the Institute for Solid State Physics, the University of Tokyo. Typical NMR-CT images of volunteers and patients obtained in the clinical experiments using this device are presented. Detailed specifications are also shown about the practical NMR-CTs which are to be put on the market after obtaining the government approval. (author)

  16. NMR imaging and pharmaceutical sciences

    International Nuclear Information System (INIS)

    Beall, P.T.; Good, W.R.

    1986-01-01

    Described is the technique of NMR-imaging in diagnostic medicine. Proton and phosphorus NMR in diagnosis of abnormal tissue pathology. Discussed is the value of NMR to the pharmaceutical sciences. NMR may play an important role in monitoring the response of tissues to drugs, determining the localization of drugs, performing real time pharmacokinetics and testing the use of NMR contrast pharmaceuticals

  17. Anomalous N=2 superconformal Ward identities

    International Nuclear Information System (INIS)

    Ketov, Sergei V.

    2000-01-01

    The N=2 superconformal Ward identities and their anomalies are discussed in N=2 superspace (including N=2 harmonic superspace), at the level of the low-energy effective action (LEEA) in four-dimensional N=2 supersymmetric field theories. The (first) chiral N=2 supergravity compensator is related to the known N=2 anomalous Ward identity in the N=2 (abelian) vector mulitplet sector. As regards the hypermultiplet LEEA given by the N=2 non-linear sigma-model (NLSM), a new anomalous N=2 superconformal Ward identity is found, whose existence is related to the (second) analytic compensator in N=2 supergravity. The celebrated solution of Seiberg and Witten is known to obey the (first) anomalous Ward identity in the Coulomb branch. We find a few solutions to the new anomalous Ward identity, after making certain assumptions about unbroken internal symmetries. Amongst the N=2 NLSM target space metrics governing the hypermultiplet LEEA are the SU(2)-Yang-Mills-Higgs monopole moduli-space metrics that can be encoded in terms of the spectral curves (Riemann surfaces), similarly to the Seiberg-Witten-type solutions. After a dimensional reduction to three spacetime dimensions (3d), our results support the mirror symmetry between the Coulomb and Higgs branches in 3d, N=4 gauge theories

  18. Lectures on pulsed NMR

    International Nuclear Information System (INIS)

    Pines, A.

    1988-08-01

    These lectures discuss some recent developments in pulsed NMR, emphasizing fundamental principles with selected illustrative applications. Major topics covered include multiple-quantum spectroscopy, spin decoupling, the interaction of spins with a quantized field, adiabatic rapid passage, spin temperature and statistics of cross-polarization, coherent averaging, and zero field NMR. 32 refs., 56 figs

  19. Lectures on pulsed NMR

    International Nuclear Information System (INIS)

    Pines, A.

    1986-09-01

    These lectures discuss some recent developments in pulsed NMR, emphasizing fundamental principles with selected illustrative applications. Major topics covered include multiple-quantum spectroscopy, spin decoupling, the interaction of spins with a quantized field, adiabatic rapid passage, spin temperature and statistics of cross-polarization, coherent averaging, and zero field NMR. 55 figs

  20. N=2 current algebra and coset models

    International Nuclear Information System (INIS)

    Hull, C.M.; Spence, B.

    1990-01-01

    The N=2 supersymmetric extension of the Kac-Moody algebra and the corresponding Sugawara construction of the N=2 superconformal algebra are discussed both in components and in N=1 superspace. A formulation of the Kac-Moody algebra and Sugawara construction is given in N=2 superspace in terms of supercurrents satisfying a non-linear chiral constraint. The operator product of two supercurrents includes terms that are non-linear in the supercurrents. The N=2 generalization of the GKO coset construction is then given and the conditions found by Kazama and Suzuki are seen to arise from the non-linearity of the algebra. (orig.)

  1. Unconstrained multiplet in N=2 conformal supergravity

    International Nuclear Information System (INIS)

    Hayashi, Masahito; Uehara, Shozo.

    1985-02-01

    An unconstrained (general) multiplet was studied in N = 2 conformal supergravity. Transformation law, embedding formula and multiplication rule are explicitly presented at the linearized level. (author)

  2. Spontaneous symmetry breaking in N = 2 supergravity

    International Nuclear Information System (INIS)

    Zinov'ev, Y.M.

    1987-01-01

    A model describing the interaction of N = 2 supergravity with a vector and a linear multiplet is constructed. The model admits the introduction of spontaneous supersymmetry breaking with two arbitrary scales, one of which can be equal to zero, corresponding to the partial super-Higgs effect (N = 2→N = 1). The cosmological term is automatically equal to zero

  3. Functional studies using NMR

    International Nuclear Information System (INIS)

    McCready, V.R.; Leach, M.O.; Sutton; Ell, P.

    1986-01-01

    The object of this book is to discuss and evaluate an area of Nuclear Magnetic Resonance which to date has been less emphasized than it might be, namely the use of NMR for functional studies. The book commences with a discussion of the areas in which the NMR techniques might be needed due to deficiencies in other techniques. The physics of NMR especially relating to functional measurement are then explained. Technical factors in producing functional images are discussed and the use of paramagnetic substances for carrying out flow studies are detailed. Particular attention is paid to specific studies in the various organs. The book ends with a survey of imaging in each organ and the relation of NMR images to other techniques such as ultrasound, nuclear medicine and X-rays

  4. Functional studies using NMR

    International Nuclear Information System (INIS)

    McCready, V.R.; Leach, M.; Ell, P.J.

    1987-01-01

    This volume is based on a series of lectures delivered at a one-day teaching symposium on functional and metabolic aspects of NMR measurements held at the Middlesex Hospital Medical School on 1st September 1985 as a part of the European Nuclear Medicine Society Congress. Currently the major emphasis in medical NMR in vivo is on its potential to image and display abnormalities in conventional radiological images, providing increased contrast between normal and abnormal tissue, improved definition of vasculature, and possibly an increased potential for differential diagnosis. Although these areas are undeniably of major importance, it is probable that NMR will continue to complement conventional measurement methods. The major potential benefits to be derived from in vivo NMR measurements are likely to arise from its use as an instrument for functional and metabolic studies in both clinical research and in the everyday management of patients. It is to this area that this volume is directed

  5. NMR of unfolded proteins

    Indian Academy of Sciences (India)

    Unknown

    2005-01-03

    Jan 3, 2005 ... covering all the systems, so far discovered.5,7,8,12. With the increasing ... Structural investigations on proteins by NMR are, currently ... rapid analysis of unfolded proteins. ...... and hence help in design of drugs against them.

  6. Theory of NMR probe design

    International Nuclear Information System (INIS)

    Schnall, M.D.

    1988-01-01

    The NMR probe is the intrinsic part of the NMR system which allows transmission of a stimulus to a sample and the reception of a resulting signal from a sample. NMR probes are used in both imaging and spectroscopy. Optimal probe design is important to the production of adequate signal/moise. It is important for anyone using NMR techniques to understand how NMR probes work and how to optimize probe design

  7. Goldstino superfields in N=2 supergravity

    Energy Technology Data Exchange (ETDEWEB)

    Kuzenko, Sergei M.; McArthur, Ian N. [School of Physics and Astrophysics M013, The University of Western Australia,35 Stirling Highway, Crawley W.A. 6009 (Australia); Tartaglino-Mazzucchelli, Gabriele [Instituut voor Theoretische Fysica, KU Leuven,Celestijnenlaan 200D, B-3001 Leuven (Belgium)

    2017-05-11

    We present off-shell N=2 supergravity actions, which exhibit spontaneously broken local supersymmetry and allow for de Sitter vacua for certain values of the parameters. They are obtained by coupling the standard N=2 supergravity-matter systems to the Goldstino superfields introduced in arXiv:1105.3001 and arXiv:1607.01277 in the rigid supersymmetric case. These N=2 Goldstino superfields include nilpotent chiral and linear supermultiplets. We also describe a new reducible N=1 Goldstino supermultiplet.

  8. Mixed OPEs in N=2 superconformal theories

    International Nuclear Information System (INIS)

    Ramírez, Israel A.

    2016-01-01

    Using superspace techniques, we compute the mixed OPE between an N=2 stress-tensor multiplet, a chiral multiplet and a flavor current multiplet. We perform a detailed analysis of the three-point function between two of the mentioned multiplets and a third arbitrary operator. We then solve all the constraints coming from the N=2 superconformal symmetry and from the equations of motion and/or conservation equations, and obtain all the possible operators that can appear in the expansion. This calculation is the first step towards a more general superconformal block analysis of mixed correlators in N=2 theories.

  9. N = 2 coset compactifictions with nondiagonal invariants

    International Nuclear Information System (INIS)

    Aldazabal, G.; Allekotte, I.; Font, A.

    1992-01-01

    In this paper, the authors consider four-dimensional string models obtained by tensoring N = 2 coset theories with nondiagonal modular invariants. The authors present results from a systematic analysis including moddings by discrete symmetries

  10. Measuring N2 Pressure Using Cyanobacteria

    Science.gov (United States)

    Silverman, S. N.; Kopf, S.; Gordon, R.; Bebout, B.; Som, S.

    2017-11-01

    We have shown that cyanobacteria can record information about N2 partial pressure both morphologically and isotopically, and thus may serve as useful geobarometers to help us better understand Earth's ancient atmosphere.

  11. N2O isotopomers and N2:N2O ratio as indicators of denitrification in ecosystems

    International Nuclear Information System (INIS)

    Mander, Ülo; Zaman, Mohammad

    2015-01-01

    The world is experiencing climate change and variability due to increased greenhouse gas (GHG) emissions. The main GHG’s of concern are nitrous oxide (N 2 O), carbon dioxide (CO 2 ) and methane (CH 4 ). Agriculture contributes approximately 14% of the world’s GHG emissions. Nitrous oxide is one of the key GHG and ozone (O 3 ) depleting gas, constituting 7% of the anthropogenic greenhouse effect. On a molecular basis, N 2 O has a 310- and 16-fold greater global warming potential than each of CO 2 and CH 4 , respectively, over a 100-year period. Nitrous oxide can be produced through both chemical and biochemical pathways. They occur during denitrification (the stepwise conversion of nitrate (NO 3 - ) to nitrogen gas (N 2 ) and during nitrification by ammonia-oxidizing archea (bacteria) during the oxidation of hydroxylamine (NH 2 OH) to nitrite (NO 2 - ) which is then reduced to N 2 O and N 2 by nitrifier denitrification or heterotrophic denitrification

  12. Microprocessorized NMR measurement

    International Nuclear Information System (INIS)

    Rijllart, A.

    1984-01-01

    An MC68000 CAMAC microprocessor system for fast and accurate NMR signal measurement will be presented. A stand-alone CAMAC microprocessor system (MC68000 STAC) with a special purpose interface sweeps a digital frequency synthesizer and digitizes the NMR signal with a 16-bit ADC of 17 μs conversion time. It averages the NMR signal data over many sweeps and then transfers it through CAMAC to a computer for calculation of the signal parameters. The computer has full software control over the timing and sweep settings of this signal averager, and thus allows optimization of noise suppression. Several of these processor systems can be installed in the same crate for parallel processing, and the flexibility of the STAC also allows easy adaptation to other applications such as transient recording or phase-sensitive detection. (orig.)

  13. Fourier transform NMR

    International Nuclear Information System (INIS)

    Hallenga, K.

    1991-01-01

    This paper discusses the concept of Fourier transformation one of the many precious legacies of the French mathematician Jean Baptiste Joseph Fourier, essential for understanding the link between continuous-wave (CW) and Fourier transform (FT) NMR. Although in modern FT NMR the methods used to obtain a frequency spectrum from the time-domain signal may vary greatly, from the efficient Cooley-Tukey algorithm to very elaborate iterative least-square methods based other maximum entropy method or on linear prediction, the principles for Fourier transformation are unchanged and give invaluable insight into the interconnection of many pairs of physical entities called Fourier pairs

  14. Integrability in N=2 superconformal gauge theorie

    Energy Technology Data Exchange (ETDEWEB)

    Pomoni, Elli [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany). Theory Group; National Technical Univ. of Athens (Greece). Physics Div.

    2013-10-15

    Any N=2 superconformal gauge theory (including N=4 SYM) contains a set of local operators made only out of fields in the N=2 vector multiplet that is closed under renormalization to all loops, namely the SU(2,1 vertical stroke 2) sector. For planar N=4 SYM the spectrum of local operators can be obtained by mapping the problem to an integrable model (a spin chain in perturbation theory), in principle for any value of the coupling constant. We present a diagrammatic argument that for any planar N=2 superconformal gauge theory the SU(2,1 vertical stroke 2) Hamiltonian acting on infinite spin chains is identical to all loops to that of N=4 SYM, up to a redefinition of the coupling constant. Thus, this sector is integrable and anomalous dimensions can be, in principle, read off from the N=4 ones up to this redefinition.

  15. Integrability in N=2 superconformal gauge theories

    International Nuclear Information System (INIS)

    Pomoni, Elli; National Technical Univ. of Athens

    2013-10-01

    Any N=2 superconformal gauge theory (including N=4 SYM) contains a set of local operators made only out of fields in the N=2 vector multiplet that is closed under renormalization to all loops, namely the SU(2,1 vertical stroke 2) sector. For planar N=4 SYM the spectrum of local operators can be obtained by mapping the problem to an integrable model (a spin chain in perturbation theory), in principle for any value of the coupling constant. We present a diagrammatic argument that for any planar N=2 superconformal gauge theory the SU(2,1 vertical stroke 2) Hamiltonian acting on infinite spin chains is identical to all loops to that of N=4 SYM, up to a redefinition of the coupling constant. Thus, this sector is integrable and anomalous dimensions can be, in principle, read off from the N=4 ones up to this redefinition.

  16. The ${\\mathcal N}=2$ superconformal bootstrap

    CERN Document Server

    Beem, Christopher; Liendo, Pedro; Rastelli, Leonardo; van Rees, Balt C

    2016-01-01

    In this work we initiate the conformal bootstrap program for ${\\mathcal N}=2$ superconformal field theories in four dimensions. We promote an abstract operator-algebraic viewpoint in order to unify the description of Lagrangian and non-Lagrangian theories, and formulate various conjectures concerning the landscape of theories. We analyze in detail the four-point functions of flavor symmetry current multiplets and of ${\\mathcal N}=2$ chiral operators. For both correlation functions we review the solution of the superconformal Ward identities and describe their superconformal block decompositions. This provides the foundation for an extensive numerical analysis discussed in the second half of the paper. We find a large number of constraints for operator dimensions, OPE coefficients, and central charges that must hold for any ${\\mathcal N}=2$ superconformal field theory.

  17. International symposium on NMR spectroscopy

    International Nuclear Information System (INIS)

    The publication consists of 32 papers and presentations from the field of NMR spectroscopy applications submitted to the International Symposium on NMR Spectroscopy held at Smolenice between 29 Sep and 3 Oct, 1980. (B.S.)

  18. Nonabelian N=2 superstrings: Hamiltonian structure

    International Nuclear Information System (INIS)

    Isaev, A.P.; Ivanov, E.A.

    1991-04-01

    We examine the Hamiltonian structure of nonabelian N=2 superstring models which are the supergroup manifold extensions of N=2 Green-Schwarz superstring. We find the Kac-Moody and Virasoro type superalgebras of the relevant constraints and present elements of the corresponding quantum theory. A comparison with the type IIA Green-Schwarz superstring moving in a general curved 10-d supergravity background is also given. We find that nonabelian superstrings (for d=10) present a particular case of this general system corresponding to a special choice of the background. (author). 22 refs

  19. Covariant n2-plet mass formulas

    International Nuclear Information System (INIS)

    Davidson, A.

    1979-01-01

    Using a generalized internal symmetry group analogous to the Lorentz group, we have constructed a covariant n 2 -plet mass operator. This operator is built as a scalar matrix in the (n;n*) representation, and its SU(n) breaking parameters are identified as intrinsic boost ones. Its basic properties are: covariance, Hermiticity, positivity, charge conjugation, quark contents, and a self-consistent n 2 -1, 1 mixing. The GMO and the Okubo formulas are obtained by considering two different limits of the same generalized mass formula

  20. Single-sided NMR

    CERN Document Server

    Casanova, Federico; Blümich, Bernhard

    2011-01-01

    Single-Sided NMR describes the design of the first functioning single-sided tomograph, the related measurement methods, and a number of applications. One of the key advantages to this method is the speed at which the images are obtained.

  1. Autonomous driving in NMR.

    Science.gov (United States)

    Perez, Manuel

    2017-01-01

    The automatic analysis of NMR data has been a much-desired endeavour for the last six decades, as it is the case with any other analytical technique. This need for automation has only grown as advances in hardware; pulse sequences and automation have opened new research areas to NMR and increased the throughput of data. Full automatic analysis is a worthy, albeit hard, challenge, but in a world of artificial intelligence, instant communication and big data, it seems that this particular fight is happening with only one technique at a time (let this be NMR, MS, IR, UV or any other), when the reality of most laboratories is that there are several types of analytical instrumentation present. Data aggregation, verification and elucidation by using complementary techniques (e.g. MS and NMR) is a desirable outcome to pursue, although a time-consuming one if performed manually; hence, the use of automation to perform the heavy lifting for users is required to make the approach attractive for scientists. Many of the decisions and workflows that could be implemented under automation will depend on the two-way communication with databases that understand analytical data, because it is desirable not only to query these databases but also to grow them in as much of an automatic manner as possible. How these databases are designed, set up and the data inside classified will determine what workflows can be implemented. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  2. Effects of Carbon and Cover Crop Residues on N2O and N2 Emissions

    Science.gov (United States)

    Burger, M.; Cooperman, Y.; Horwath, W. R.

    2016-12-01

    In Mediterranean climate, nitrous oxide emissions occurring with the first rainfall after the dry summer season can contribute up to 50% of agricultural systems' total annual emissions, but the drivers of these emissions have not been clearly identified, and there are only few measurements of atmospheric nitrogen (N2) production (denitrification) during these events. In lab incubations, we investigated N2O and N2 production, gross ammonification and nitrification, and microbial N immobilization with wet-up in soil from a vineyard that was previously fallow or where cover crop residue had been incorporated the previous spring. Before the first rainfall, we measured 120 mg dissolved organic carbon (DOC-C) kg-1 soil in the 0-5 cm layer of this vineyard, and after the rain 10 mg DOC-C kg-1, while nitrate levels before the rain were cover cropped soil. The N2O/N2 production was 2, 7, 9, and 86% in fallow, legume-grass mixture, rye, and legume cover cropped soil. The N2O/N2 ratio tended to increase with lower DOC (post-rain) levels in the soil. The results suggest that accumulated carbon in dry surface soil is the main driving factor of N2O and N2 emissions through denitrification with the first rainfall after prolonged dry periods.

  3. NMR for chemists and biologists

    CERN Document Server

    Carbajo, Rodrigo J

    2013-01-01

    This book offers a concise introduction to the field of nuclear magnetic resonance or NMR. It presents the basic foundations of NMR in a non-mathematical way and provides an overview of both recent and important biological applications of NMR.

  4. Modular invariance of N=2 minimal models

    International Nuclear Information System (INIS)

    Sidenius, J.

    1991-01-01

    We prove modular covariance of one-point functions at one loop in the diagonal N=2 minimal superconformal models. We use the recently derived general formalism for computing arbitrary conformal blocks in these models. Our result should be sufficient to guarantee modular covariance at arbitrary genus. It is thus an important check on the general formalism which is not manifestly modular covariant. (orig.)

  5. Triality invariance in the N=2 superstring

    International Nuclear Information System (INIS)

    Castellani, Leonardo; Grassi, Pietro Antonio; Sommovigo, Luca

    2009-01-01

    We prove the discrete triality invariance of the N=2 NSR superstring moving in a D=2+2 target space. We find that triality holds also in the Siegel-Berkovits formulation of the selfdual superstring. A supersymmetric generalization of Cayley's hyperdeterminant, based on a quartic invariant of the SL(2|1) 3 superalgebra, is presented.

  6. Triality invariance in the N=2 superstring

    Energy Technology Data Exchange (ETDEWEB)

    Castellani, Leonardo [Dipartimento di Scienze e Tecnologie Avanzate and INFN Gruppo collegato di Alessandria, Universita del Piemonte Orientale, Via Teresa Michel 11, 15121 Alessandria (Italy)], E-mail: leonardo.castellani@mfn.unipmn.it; Grassi, Pietro Antonio [Dipartimento di Scienze e Tecnologie Avanzate and INFN Gruppo collegato di Alessandria, Universita del Piemonte Orientale, Via Teresa Michel 11, 15121 Alessandria (Italy)], E-mail: pietro.grassi@mfn.unipmn.it; Sommovigo, Luca [Dipartimento di Scienze e Tecnologie Avanzate and INFN Gruppo collegato di Alessandria, Universita del Piemonte Orientale, Via Teresa Michel 11, 15121 Alessandria (Italy)], E-mail: luca.sommovigo@mfn.unipmn.it

    2009-07-20

    We prove the discrete triality invariance of the N=2 NSR superstring moving in a D=2+2 target space. We find that triality holds also in the Siegel-Berkovits formulation of the selfdual superstring. A supersymmetric generalization of Cayley's hyperdeterminant, based on a quartic invariant of the SL(2|1){sup 3} superalgebra, is presented.

  7. Extremal black holes in N=2 supergravity

    NARCIS (Netherlands)

    Katmadas, S.

    2011-01-01

    An explanation for the entropy of black holes has been an outstanding problem in recent decades. A special case where this is possible is that of extremal black holes in N=2 supergravity in four and five dimensions. The best developed case is for black holes preserving some supersymmetry (BPS),

  8. Nanosecond pulsed discharges in N2 and N2/H2O mixtures

    NARCIS (Netherlands)

    Joosten, R.M.; Verreycken, T.; Veldhuizen, van E.M.; Bruggeman, P.J.

    2011-01-01

    Nanosecond pulsed discharges in N2 and N2/H2O at atmospheric pressure between two pin-shaped electrodes are studied. The evolution of the discharge is investigated with time-resolved imaging and optical emission spectroscopy. The discharge consists of three phases, the ignition (mainly molecular

  9. Isometries, gaugings and N=2 supergravity decoupling

    Energy Technology Data Exchange (ETDEWEB)

    Antoniadis, Ignatios [Laboratoire de Physique Théorique et Hautes Energies, Sorbonne Universités,CNRS UMR 7589, UPMC Paris 6, 4 place Jussieu, 75005 Paris (France); Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics,University of Bern,Sidlerstrasse 5, 3012 Bern (Switzerland); Derendinger, Jean-Pierre [Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics,University of Bern,Sidlerstrasse 5, 3012 Bern (Switzerland); Petropoulos, P. Marios [Centre de Physique Théorique, Ecole Polytechnique, CNRS UMR 7644, Université Paris-Saclay,91128 Palaiseau Cedex (France); Laboratoire de Physique Théorique et Hautes Energies, Sorbonne Universités,CNRS UMR 7589, UPMC Paris 6, 4 place Jussieu, 75005 Paris (France); Siampos, Konstantinos [Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics,University of Bern,Sidlerstrasse 5, 3012 Bern (Switzerland)

    2016-11-28

    We study off-shell rigid limits for the kinetic and scalar-potential terms of a single N=2 hypermultiplet. In the kinetic term, these rigid limits establish relations between four-dimensional quaternion-Kähler and hyper-Kähler target spaces with symmetry. The scalar potential is obtained by gauging the graviphoton along an isometry of the quaternion-Kähler space. The rigid limits unveil two distinct cases. A rigid N=2 theory on Minkowski or on AdS{sub 4} spacetime, depending on whether the isometry is translational or rotational respectively. We apply these results to the quaternion-Kähler space with Heisenberg⋉U(1) isometry, which describes the universal hypermultiplet at type-II string one-loop.

  10. On classification of N=2 supersymmetric theories

    International Nuclear Information System (INIS)

    Cecotti, S.; Vafa, C.

    1993-01-01

    We find a relation between the spectrum of solitons of massive N=2 quantum field theories in d=2 and the scaling dimensions of chiral fields at the conformal point. The condition that the scaling dimensions be real imposes restrictions on the soliton numbers and leads to a classification program for symmetric N=2 conformal theories and their massive deformations in terms of a suitable generalization of Dynkin diagrams (which coincides with the A-D-E Dynkin diagrams for minimal models). The Landau-Ginzburg theories are a proper subset of this classification. In the particular case of LG theories we relate the soliton numbers with intersection of vanishing cycles of the corresponding singularity; the relation between soliton numbers and the scaling dimensions in this particular case is a well known application of Picard-Lefschetz theory. (orig.)

  11. N=2 no-scale supergravity

    Energy Technology Data Exchange (ETDEWEB)

    Itoyama, H.; McLerran, L.; Taylor, T.R.; Van der Bij, J.J.

    1987-01-12

    N=2 extended supergravity is discussed and an assessment is made of the problems encountered in applying it to the construction of phenomenological models of particle physics. A specific class of so-called no-scale models is discussed, in which the two supersymmetries are spontaneously broken in flat space-time, with naturally vanishing cosmological constant and the symmetry breaking undetermined at the classical level. Supergravity-induced supersymmetry breaking generates effective mass terms for spin-1/2 components of the vector gauge multiplets and spin-0 components of the scalar matter multiplets. For finite globally supersymmetric models, this supersymmetry breaking preserves the finiteness. Possible connections of N=2 no-scale supergravity with superstrings and finite range antigravity are mentioned.

  12. N=2 no-scale supergravity

    International Nuclear Information System (INIS)

    Itoyama, H.; McLerran, L.; Taylor, T.R.; Van der Bij, J.J.

    1987-01-01

    N=2 extended supergravity is discussed and an assessment is made of the problems encountered in applying it to the construction of phenomenological models of particle physics. A specific class of so-called no-scale models is discussed, in which the two supersymmetries are spontaneously broken in flat space-time, with naturally vanishing cosmological constant and the symmetry breaking undetermined at the classical level. Supergravity-induced supersymmetry breaking generates effective mass terms for spin-1/2 components of the vector gauge multiplets and spin-0 components of the scalar matter multiplets. For finite globally supersymmetric models, this supersymmetry breaking preserves the finiteness. Possible connections of N=2 no-scale supergravity with superstrings and finite range antigravity are mentioned. (orig.)

  13. N=2 supersymmetric dynamics for pedestrians

    CERN Document Server

    Tachikawa, Yuji

    2015-01-01

    Understanding the dynamics of gauge theories is crucial, given the fact that all known interactions are based on the principle of local gauge symmetry. Beyond the perturbative regime, however, this is a notoriously difficult problem. Requiring invariance under supersymmetry turns out to be a suitable tool for analyzing supersymmetric gauge theories over a larger region of the space of parameters. Supersymmetric quantum field theories in four dimensions with extended N=2 supersymmetry are further constrained and have therefore been a fertile field of research in theoretical physics for quite some time. Moreover, there are far-reaching mathematical ramifications that have led to a successful dialogue with differential and algebraic geometry. These lecture notes aim to introduce students of modern theoretical physics to the fascinating developments in the understanding of N=2 supersymmetric gauge theories in a coherent fashion. Starting with a gentle introduction to electric-magnetic duality, the author guides r...

  14. Phases of N=2 necklace quivers

    Directory of Open Access Journals (Sweden)

    Antonio Amariti

    2018-01-01

    Full Text Available We classify the phases of N=2 elliptic models in terms of their global properties i.e. the spectrum of line operators. We show the agreement between the field theory and the M-theory analysis and how the phases form orbits under the action of the S-duality group which corresponds to the mapping class group of the Riemann surface in M-theory.

  15. NMR, water and plants

    International Nuclear Information System (INIS)

    As, H. van.

    1982-01-01

    This thesis describes the application of a non-destructive pulsed proton NMR method mainly to measure water transport in the xylem vessels of plant stems and in some model systems. The results are equally well applicable to liquid flow in other biological objects than plants, e.g. flow of blood and other body fluids in human and animals. The method is based on a pulse sequence of equidistant π pulses in combination with a linear magnetic field gradient. (Auth.)

  16. N2O formation in combustion systems

    International Nuclear Information System (INIS)

    1989-11-01

    The objective of this project is to characterize N 2 O emissions from combustion sources emphasizing N 2 O emissions from post-combustion selective gas phase NO x reduction processes and reburning. The processes to be evaluated include ammonia, urea and cyanuric acid injection and reburning. The project includes pilot-scale testing at two facilities supported by chemical kinetic modeling. Testing will be performed on both a gas-fired plug flow combustor and a pulverized-coal fired combustor. Work performed to date has included the performance of the initial detailed chemical kinetics calculations. These calculations showed that both urea and cyanuric acid produce significant quantities of N 2 O, while NH 3 injection produced negligible amounts. These kinetics data support limited test results reported for cyanuric acid and ammonia injection. Laboratory work to evaluate the selective gas phase NO x reduction processes listed above will begin in the gas-fired facility early in CY 1990. Testing to evaluate reburning at the coal-fired facility is currently planned to be performed in parallel with the testing at the gas-fired facility. Following completion of that work, additional kinetics calculations will be performed

  17. Current problems in (n,2n) reactions

    Energy Technology Data Exchange (ETDEWEB)

    Cindro, N; Frehaut, J

    1975-01-01

    Two kinds of problems related to (n,2n) reactions are briefly discussed. The first one is the understanding of the reaction mechanism. The nucleus evaporation formulas overestimate the experimental values of the cross sections. This difference can be accounted for either by reestimating the relative values of GAMMA sub(..gamma..) and GAMMA sub(n) or by adding nonequilibrium process contributions. The second problem is the Csikai-Petoe effect. A more extensive analysis of the data shows that they are not in agreement with its predictions.

  18. Current problems in (n,2n) reactions

    International Nuclear Information System (INIS)

    Cindro, N.; Frehaut, J.

    1975-01-01

    Two kinds of problems related to (n,2n) reactions are briefly discussed. The first one is the understanding of the reaction mechanism. The nucleus evaporation formulas overestimate the experimental values of the cross sections. This difference can be accounted for either by reestimating the relative values of GAMMA sub(γ) and GAMMA sub(n) or by adding nonequilibrium process contributions. The second problem is the Csikai-Petoe effect. A more extensive analysis of the data shows that they are not in agreement with its predictions [fr

  19. Magic Angle Spinning NMR Metabolomics

    Energy Technology Data Exchange (ETDEWEB)

    Zhi Hu, Jian

    2016-01-01

    Nuclear Magnetic Resonance (NMR) spectroscopy is a non-destructive, quantitative, reproducible, untargeted and unbiased method that requires no or minimal sample preparation, and is one of the leading analytical tools for metabonomics research [1-3]. The easy quantification and the no need of prior knowledge about compounds present in a sample associated with NMR are advantageous over other techniques [1,4]. 1H NMR is especially attractive because protons are present in virtually all metabolites and its NMR sensitivity is high, enabling the simultaneous identification and monitoring of a wide range of low molecular weight metabolites.

  20. NMR in clinical practice

    International Nuclear Information System (INIS)

    Smith, F.W.

    1987-01-01

    The development of NMR for clinical use has been complicated by a number of controversies, the largest of these being the question of what is the optimum field strength for proton imaging. Many workers believe that diagnostically useful images can only be produced at high field strength (i.e. 0.5 - 2.0 T), where in fact diagnostically useful images are made using field strengths of as low as 0.02 T. Because the method is more complex than X-ray CT, which relies on the measurement of only one parameter, tissue density, many new users have difficulty in selecting the correct imaging pulse sequence to provide the most useful image for diagnosis. NMR imaging pulse sequence may be selected to produce images of the proton density, T/sub 1/ or T/sub 2/ signals, or combinations of them. When this facility is used, images which are T/sub 1/ or T/sub 2/ weighted can be selected. Inversion-recovery sequences are more appropriate for imaging the abdomen where by selecting a short TR interval the signal from subcutaneous fat, which is the major cause of image artefact in abdominal imaging, is suppressed thereby improving image quality. The use of surface receiver coils, which are applied closely to the area of the body being examined is becoming more widespread and is of particular value when examining the orbits, facial structures, neck, breast, spine and limbs. The use of these coils together with a discussion of patient selection for NMR imaging, image interpretation and data storage follow

  1. 15N Hyperpolarization of Imidazole-15N2 for Magnetic Resonance pH Sensing via SABRE-SHEATH.

    Science.gov (United States)

    Shchepin, Roman V; Barskiy, Danila A; Coffey, Aaron M; Theis, Thomas; Shi, Fan; Warren, Warren S; Goodson, Boyd M; Chekmenev, Eduard Y

    2016-06-24

    15 N nuclear spins of imidazole- 15 N 2 were hyperpolarized using NMR signal amplification by reversible exchange in shield enables alignment transfer to heteronuclei (SABRE-SHEATH). A 15 N NMR signal enhancement of ∼2000-fold at 9.4 T is reported using parahydrogen gas (∼50% para-) and ∼0.1 M imidazole- 15 N 2 in methanol:aqueous buffer (∼1:1). Proton binding to a 15 N site of imidazole occurs at physiological pH (p K a ∼ 7.0), and the binding event changes the 15 N isotropic chemical shift by ∼30 ppm. These properties are ideal for in vivo pH sensing. Additionally, imidazoles have low toxicity and are readily incorporated into a wide range of biomolecules. 15 N-Imidazole SABRE-SHEATH hyperpolarization potentially enables pH sensing on scales ranging from peptide and protein molecules to living organisms.

  2. Synthesis, Spectral and Antimicrobial Studies of Some N(2)-Substituted Tetrahydroindazoles

    International Nuclear Information System (INIS)

    Amirthaganesan, Shanmugasundaram; Aridoss, Gopalakrishnan; Park, Keun Soo; Lim, Kwon Taek; Jeong, Yeon Tae

    2010-01-01

    A series of N(2)-benzothiazolyl substituted tetrahydroindazoles has been synthesized via cyclic β keto esters. Optimum reaction condition was found as acidic toluene and effect of higher acidity towards substituted hydrazines in situ was described. Synthesized compounds have been achieved as single isomer and characterized by using 1D and 2D NMR spectral reports. Antimicrobial screening was carried out for the synthesized compounds along with a series of N(2)-pyridyl tetrahydroindazoles. 1 The results of the in vitro antimicrobial screening studies revealed that compounds 13, 16 against Staphylococcus aureus, 11 against Escherichia coli, 10-12, 16 against Pseudomonas aeruginosa and 12 against Klebsiella pneumoniae recorded almost two-fold better activity compared to the standard drug used

  3. Lepton mixing from Δ(3n2 and Δ(6n2 and CP

    Directory of Open Access Journals (Sweden)

    Claudia Hagedorn

    2015-02-01

    Full Text Available We perform a detailed study of lepton mixing patterns arising from a scenario with three Majorana neutrinos in which a discrete flavor group Gf=Δ(3n2 or Gf=Δ(6n2 and a CP symmetry are broken to residual symmetries Ge=Z3 and Gν=Z2×CP in the charged lepton and neutrino sectors, respectively. While we consider all possible Z3 and Z2 generating elements, we focus on a certain set of CP transformations. The resulting lepton mixing depends on group theoretical indices and one continuous parameter. In order to study the mixing patterns comprehensively for all admitted Ge and Gν, it is sufficient to discuss only three types of combinations. One of them requires as flavor group Δ(6n2. Two types of combinations lead to mixing patterns with a trimaximal column, while the third one allows for a much richer structure. For the first type of combinations the Dirac phase as well as one of the Majorana phases are trivial, whereas the other two types of combinations predict in general all CP phases to be non-trivial and also non-maximal. Already for small values of the index n of the group, n≤11, experimental data on lepton mixing can be accommodated well for particular choices of the parameters of the theory. We also comment on the relation of the used CP transformations to the automorphisms of Δ(3n2 and Δ(6n2.

  4. Background harmonic superfields in N=2 supergravity

    International Nuclear Information System (INIS)

    Zupnik, B.M.

    1998-01-01

    A modification of the harmonic superfield formalism in D=4, N=2 supergravity using a subsidiary condition of covariance under the background supersymmetry with a central charge (B-covariance) is considered. Conservation of analyticity together with the B-covariance leads to the appearance of linear gravitational superfields. Analytic prepotentials arise in a decomposition of the background linear superfields in terms of spinor coordinates and transform in a nonstandard way under the background supersymmetry. The linear gravitational superfields can be written via spinor derivatives of nonanalytic spinor prepotentials. The perturbative expansion of supergravity action in terms of the B-covariant superfields and the corresponding version of the differential-geometric formalism are considered. We discuss the dual harmonic representation of the linearized extended supergravity, which corresponds to the dynamical condition of Grassmann analyticity

  5. Boundary rings and N=2 coset models

    International Nuclear Information System (INIS)

    Lerche, W.; Walcher, J.

    2002-01-01

    We investigate boundary states of N=2 coset models based on Grassmannians Gr(n,n+k), and find that the underlying intersection geometry is given by the fusion ring of U(n). This is isomorphic to the quantum cohomology ring of Gr(n,n+k+1), which in turn can be encoded in a 'boundary' superpotential whose critical points correspond to the boundary states. In this way the intersection properties can be represented in terms of a soliton graph that forms a generalized, Z n+k+1 symmetric McKay quiver. We investigate the spectrum of bound states and find that the rational boundary CFT produces only a small subset of the possible quiver representations

  6. NMR spectroscopy and drug development

    International Nuclear Information System (INIS)

    Craik, D.; Munro, S.

    1990-01-01

    The use of nuclear magnetic resonance (NMR) spectroscopy for structural and conformational studies on drug molecules, the three-dimensional investigation of proteins structure and their interactions with ligands are discussed. In-vivo NMR studies of the effects of drugs on metabolism in perfused organs and whole animals are also briefly presented. 5 refs., ills

  7. NMR in pulsed magnetic field

    KAUST Repository

    Abou-Hamad, Edy; Bontemps, P.; Rikken, Geert L J A

    2011-01-01

    Nuclear magnetic resonance (NMR) experiments in pulsed magnetic fields up to 30.4 T focused on 1H and 93Nb nuclei are reported. Here we discuss the advantage and limitation of pulsed field NMR and why this technique is able to become a promising research tool. © 2011 Elsevier Inc. All Rights Reserved.

  8. NMR imaging of osteoarticular pathology

    International Nuclear Information System (INIS)

    Frocrain, L.; Duvauferrier, R.; Gagey, N.

    1987-01-01

    NMR imaging is assuming an increasingly important role in the diagnosis of osteo-articular disorders. Semiological descriptions of the mean pathological disorders of the locomotor system are presented. Some investigation strategies are proposed to compare NMR imaging with other imaging techniques in various pathological states [fr

  9. Nuclear magnetic resonance (NMR) tomography

    International Nuclear Information System (INIS)

    Skalpe, I.O.

    1984-01-01

    A brief survey of the working principle of the NMR technique in diagnostical medicine is given. Its clinical usefulness for locating tumors, diagnosing various other diseases, such as some mental illnesses and multiple sclerosis, and its possibilities for studying biochemical processes in vivo are mentioned. The price of NMR image scanners and the problems of the strong magnetic field around the machines are mentioned

  10. NMR imaging studies of coal

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Z.R.; Zhang, P.Z.; Ding, G.L.; Li, L.Y.; Ye, C.H. [University of Science and Technology, Beijing (China). Dept. of Chemistry

    1996-06-01

    The permeation transportation and swelling behavior of solvents into coal are investigated by NMR imaging using pyridine-d{sub 5} and acetone-d{sub 6}. Images of coal swollen with deuterated solvents illuminate proton distributions of mobile phases within the coal macromolecular networks. More information about the chemical and physical structure of coal can be obtained using NMR imaging techniques.

  11. NMR in pulsed magnetic field

    KAUST Repository

    Abou-Hamad, Edy

    2011-09-01

    Nuclear magnetic resonance (NMR) experiments in pulsed magnetic fields up to 30.4 T focused on 1H and 93Nb nuclei are reported. Here we discuss the advantage and limitation of pulsed field NMR and why this technique is able to become a promising research tool. © 2011 Elsevier Inc. All Rights Reserved.

  12. Structural Biology: Practical NMR Applications

    CERN Document Server

    Teng, Quincy

    2005-01-01

    This textbook begins with an overview of NMR development and applications in biological systems. It describes recent developments in instrument hardware and methodology. Chapters highlight the scope and limitation of NMR methods. While detailed math and quantum mechanics dealing with NMR theory have been addressed in several well-known NMR volumes, chapter two of this volume illustrates the fundamental principles and concepts of NMR spectroscopy in a more descriptive manner. Topics such as instrument setup, data acquisition, and data processing using a variety of offline software are discussed. Chapters further discuss several routine stategies for preparing samples, especially for macromolecules and complexes. The target market for such a volume includes researchers in the field of biochemistry, chemistry, structural biology and biophysics.

  13. Fundamentals of Protein NMR Spectroscopy

    CERN Document Server

    Rule, Gordon S

    2006-01-01

    NMR spectroscopy has proven to be a powerful technique to study the structure and dynamics of biological macromolecules. Fundamentals of Protein NMR Spectroscopy is a comprehensive textbook that guides the reader from a basic understanding of the phenomenological properties of magnetic resonance to the application and interpretation of modern multi-dimensional NMR experiments on 15N/13C-labeled proteins. Beginning with elementary quantum mechanics, a set of practical rules is presented and used to describe many commonly employed multi-dimensional, multi-nuclear NMR pulse sequences. A modular analysis of NMR pulse sequence building blocks also provides a basis for understanding and developing novel pulse programs. This text not only covers topics from chemical shift assignment to protein structure refinement, as well as the analysis of protein dynamics and chemical kinetics, but also provides a practical guide to many aspects of modern spectrometer hardware, sample preparation, experimental set-up, and data pr...

  14. "N"-2 Repetition Costs Depend on Preparation in Trials "n"-1 and "n"-2

    Science.gov (United States)

    Scheil, Juliane; Kleinsorge, Thomas

    2014-01-01

    In task switching, a common result supporting the notion of inhibitory processes as a determinant of switch costs is the occurrence of "n"-2 repetition costs. Evidence suggests that this effect is not affected by preparation. However, the role of preparation on preceding trials has been neglected so far. In this study, evidence for an…

  15. Off-shell N = 2 tensor supermultiplets

    International Nuclear Information System (INIS)

    Wit, Bernard de; Saueressig, Frank

    2006-01-01

    A multiplet calculus is presented for an arbitrary number n of N = 2 tensor supermultiplets. For rigid supersymmetry the known couplings are reproduced. In the superconformal case the target spaces parametrized by the scalar fields are cones over (3n-1)-dimensional spaces encoded in homogeneous SU(2) invariant potentials, subject to certain constraints. The coupling to conformal supergravity enables the derivation of a large class of supergravity Lagrangians with vector and tensor multiplets and hypermultiplets. Dualizing the tensor fields into scalars leads to hypermultiplets with hyperkaehler or quaternion-Kaehler target spaces with at least n abelian isometries. It is demonstrated how to use the calculus for the construction of Lagrangians containing higher-derivative couplings of tensor multiplets. For the application of the c-map between vector and tensor supermultiplets to Lagrangians with higher-order derivatives, an off-shell version of this map is proposed. Various other implications of the results are discussed. As an example an elegant derivation of the classification of 4-dimensional quaternion-Kaehler manifolds with two commuting isometries is given

  16. Spectroscopic study, antimicrobial activity and crystal structures of N-(2-hydroxy-5-nitrobenzalidene)4-aminomorpholine and N-(2-hydroxy-1-naphthylidene)4-aminomorpholine

    Science.gov (United States)

    Yıldız, Mustafa; Ünver, Hüseyin; Dülger, Başaran; Erdener, Diğdem; Ocak, Nazan; Erdönmez, Ahmet; Durlu, Tahsin Nuri

    2005-03-01

    Schiff bases N-(2-hydroxy-3-nitrobenzalidene)4-aminomorpholine ( 1) and N-(2-hydroxy-1-naphthylidene)4-aminomorpholine ( 2) were synthesized from the reaction of 4-aminomorpholine with 2-hydroxy-5-nitrobenzaldehyde and 2-hydroxy-1-naphthaldehyde. Compounds 1 and 2 were characterized by elemental analysis, IR, 1H NMR, 13C NMR and UV-Visible techniques. The UV-Visible spectra of the Schiff bases with OH group in ortho position to the imino group were studied in polar and nonpolar solvents in acidic and basic media. The structures of compounds 1 and 2 have been examined cyrstallographically, for two compounds exist as dominant form of enol-imines in both the solutions and solid state. The title compounds 1 and 2 crystallize in the monoclinic space group P2 1/ c and P2 1/ n with unit cell parameters: a=8.410(1) and 11.911(3), b=6.350(9) and 4.860(9), c=21.728(3) and 22.381(6) Å, β=90.190(1) and 95.6(2)°, V=1160.6(3) and 1289.5(5) Å 3, Dx=1.438 and 1.320 g cm -3, respectively. The crystal structures were solved by direct methods and refined by full-matrix least squares. The antimicrobial activities of compounds 1 and 2 have also been studied. The antimicrobial activities of the ligands have been screened in vitro against the organisms Escherichia coli ATCC 11230, Staphylococcus aureus ATCC 6538, Klebsiella pneumoniae UC57, Micrococcus luteus La 2971, Proteus vulgaris ATCC 8427, Pseudomonas aeruginosa ATCC 27853, Mycobacterium smegmatis CCM 2067, Bacillus cereus ATCC 7064, Listeria monocytogenes ATCC 15313, Candida albicans ATCC 10231, Kluyveromyces fragilis NRRL 2415, Rhodotorula rubra DSM 70403, Debaryomyces hansenii DSM 70238 and Hanseniaspora guilliermondii DSM 3432.

  17. Two dimensional solid state NMR

    International Nuclear Information System (INIS)

    Kentgens, A.P.M.

    1987-01-01

    This thesis illustrates, by discussing some existing and newly developed 2D solid state experiments, that two-dimensional NMR of solids is a useful and important extension of NMR techniques. Chapter 1 gives an overview of spin interactions and averaging techniques important in solid state NMR. As 2D NMR is already an established technique in solutions, only the basics of two dimensional NMR are presented in chapter 2, with an emphasis on the aspects important for solid spectra. The following chapters discuss the theoretical background and applications of specific 2D solid state experiments. An application of 2D-J resolved NMR, analogous to J-resolved spectroscopy in solutions, to natural rubber is given in chapter 3. In chapter 4 the anisotropic chemical shift is mapped out against the heteronuclear dipolar interaction to obtain information about the orientation of the shielding tensor in poly-(oxymethylene). Chapter 5 concentrates on the study of super-slow molecular motions in polymers using a variant of the 2D exchange experiment developed by us. Finally chapter 6 discusses a new experiment, 2D nutation NMR, which makes it possible to study the quadrupole interaction of half-integer spins. 230 refs.; 48 figs.; 8 tabs

  18. N=2 super - W3(2) algebra in superfields

    International Nuclear Information System (INIS)

    Krivonos, S.; Sorin, A.

    1995-05-01

    It is presented a manifestly N=2 supersymmetric formulation of N=2 super-W 3 (2) algebra (its classical version) in terms of the spin 1 unconstrained generating a N=2 superconformal subalgebra and the spins 1/2, 2 fermionic constrained supercurrents. It is considered a superfield reduction of N=2 super-W 3 (2) to N=2 super-W 3 and construct a family of evolution equations for which N=2 super-W 3 (2) provides the second Hamiltonian structure

  19. nmr spectroscopic study and dft calculations of giao nmr shieldings

    African Journals Online (AJOL)

    Preferred Customer

    3Department of Physics, Arts and Science Faculty, Dumlupinar University, Kütahya, ... 1H, 13C NMR chemical shifts and 1JCH coupling constants of .... then estimated using the corresponding TMS shieldings calculated in advance at the same.

  20. NMR-based milk metabolomics

    DEFF Research Database (Denmark)

    Sundekilde, Ulrik; Larsen, Lotte Bach; Bertram, Hanne Christine S.

    2013-01-01

    and processing capabilities of bovine milk is closely associated to milk composition. Metabolomics is ideal in the study of the low-molecular-weight compounds in milk, and this review focuses on the recent nuclear magnetic resonance (NMR)-based metabolomics trends in milk research, including applications linking...... compounds. Furthermore, metabolomics applications elucidating how the differential regulated genes affects milk composition are also reported. This review will highlight the recent advances in NMR-based metabolomics on milk, as well as give a brief summary of when NMR spectroscopy can be useful for gaining...

  1. Annual reports on NMR spectroscopy

    CERN Document Server

    Webb, Graham A; McCarthy, M J

    1995-01-01

    Over recent years, no other technique has grown to such importance as that of NMR spectroscopy. It is used in all branches of science where precise structural determination is required and where the nature of interactions and reactions in solution is being studied. Annual Reports on NMR Spectroscopy has established itself as a means for the specialist and non-specialist alike to become familiar with new applications of the technique in all branches of chemistry, including biochemistry, and pharmaceutics. This volume focuses on theoretical aspects of NMR nuclear shielding and on applications of

  2. Life on N2O: deciphering the ecophysiology of N2O respiring bacterial communities in a continuous culture.

    Science.gov (United States)

    Conthe, Monica; Wittorf, Lea; Kuenen, J Gijs; Kleerebezem, Robbert; van Loosdrecht, Mark C M; Hallin, Sara

    2018-04-01

    Reduction of the greenhouse gas N 2 O to N 2 is a trait among denitrifying and non-denitrifying microorganisms having an N 2 O reductase, encoded by nosZ. The nosZ phylogeny has two major clades, I and II, and physiological differences among organisms within the clades may affect N 2 O emissions from ecosystems. To increase our understanding of the ecophysiology of N 2 O reducers, we determined the thermodynamic growth efficiency of N 2 O reduction and the selection of N 2 O reducers under N 2 O- or acetate-limiting conditions in a continuous culture enriched from a natural community with N 2 O as electron acceptor and acetate as electron donor. The biomass yields were higher during N 2 O limitation, irrespective of dilution rate and community composition. The former was corroborated in a continuous culture of Pseudomonas stutzeri and was potentially due to cytotoxic effects of surplus N 2 O. Denitrifiers were favored over non-denitrifying N 2 O reducers under all conditions and Proteobacteria harboring clade I nosZ dominated. The abundance of nosZ clade II increased when allowing for lower growth rates, but bacteria with nosZ clade I had a higher affinity for N 2 O, as defined by μ max /K s . Thus, the specific growth rate is likely a key factor determining the composition of communities living on N 2 O respiration under growth-limited conditions.

  3. QCL N2O data final MayAugust2016

    Data.gov (United States)

    U.S. Environmental Protection Agency — The dataset consists of daily measurements of N2O, N2O isotopic abundance and site preference, and CO2 flux. Data are presented as a daily averages of 10 second...

  4. N=2 supergravity in superspace and the BRS symmetry

    International Nuclear Information System (INIS)

    Kachkachi, M.; Lhallabi, T.

    1989-07-01

    The quantum N = 2 Einstein supergravity action is constructed by requiring the BRS symmetry. This latter is derived by the use of the distorted horizontality conditions in the curved N = 2 harmonic superspace. (author). 16 refs

  5. Singular dimensions of the N=2 superconformal algebras II: The twisted N=2 algebra

    International Nuclear Information System (INIS)

    Doerrzapf, M.; Gato-Rivera, B.

    2001-01-01

    We introduce a suitable adapted ordering for the twisted N=2 superconformal algebra (i.e. with mixed boundary conditions for the fermionic fields). We show that the ordering kernels for complete Verma modules have two elements and the ordering kernels for G-closed Verma modules just one. Therefore, spaces of singular vectors may be two-dimensional for complete Verma modules whilst for G-closed Verma modules they can only be one-dimensional. We give all singular vectors for the levels (1)/(2), 1, and (3)/(2) for both complete Verma modules and G-closed Verma modules. We also give explicite examples of degenerate cases with two-dimensional singular vector spaces in complete Verma modules. General expressions are conjectured for the relevant terms of all (primitive) singular vectors, i.e. for the coefficients with respect to the ordering kernel. These expressions allow to identify all degenerate cases as well as all G-closed singular vectors. They also lead to the discovery of subsingular vectors for the twisted N=2 superconformal algebra. Explicit examples of these subsingular vectors are given for the levels (1)/(2), 1, and (3)/(2). Finally, the multiplication rules for singular vector operators are derived using the ordering kernel coefficients. This sets the basis for the analysis of the twisted N=2 embedding diagrams. (orig.)

  6. β-NMR sample optimization

    CERN Document Server

    Zakoucka, Eva

    2013-01-01

    During my summer student programme I was working on sample optimization for a new β-NMR project at the ISOLDE facility. The β-NMR technique is well-established in solid-state physics and just recently it is being introduced for applications in biochemistry and life sciences. The β-NMR collaboration will be applying for beam time to the INTC committee in September for three nuclei: Cu, Zn and Mg. Sample optimization for Mg was already performed last year during the summer student programme. Therefore sample optimization for Cu and Zn had to be completed as well for the project proposal. My part in the project was to perform thorough literature research on techniques studying Cu and Zn complexes in native conditions, search for relevant binding candidates for Cu and Zn applicable for ß-NMR and eventually evaluate selected binding candidates using UV-VIS spectrometry.

  7. NMR Studies of Polymer Nanocomposites

    National Research Council Canada - National Science Library

    Greenbaum, Steve

    2001-01-01

    .... The primary tool is pulsed field gradient NMR. A static field gradient method was developed which makes possible variable pressure diffusion measurement, and the application to the important fuel cell membrane NAFION constitute the first results...

  8. Integrative NMR for biomolecular research

    International Nuclear Information System (INIS)

    Lee, Woonghee; Cornilescu, Gabriel; Dashti, Hesam; Eghbalnia, Hamid R.; Tonelli, Marco; Westler, William M.; Butcher, Samuel E.; Henzler-Wildman, Katherine A.; Markley, John L.

    2016-01-01

    NMR spectroscopy is a powerful technique for determining structural and functional features of biomolecules in physiological solution as well as for observing their intermolecular interactions in real-time. However, complex steps associated with its practice have made the approach daunting for non-specialists. We introduce an NMR platform that makes biomolecular NMR spectroscopy much more accessible by integrating tools, databases, web services, and video tutorials that can be launched by simple installation of NMRFAM software packages or using a cross-platform virtual machine that can be run on any standard laptop or desktop computer. The software package can be downloaded freely from the NMRFAM software download page ( http://pine.nmrfam.wisc.edu/download-packages.html http://pine.nmrfam.wisc.edu/download_packages.html ), and detailed instructions are available from the Integrative NMR Video Tutorial page ( http://pine.nmrfam.wisc.edu/integrative.html http://pine.nmrfam.wisc.edu/integrative.html ).

  9. Integrative NMR for biomolecular research

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Woonghee, E-mail: whlee@nmrfam.wisc.edu; Cornilescu, Gabriel; Dashti, Hesam; Eghbalnia, Hamid R.; Tonelli, Marco; Westler, William M.; Butcher, Samuel E.; Henzler-Wildman, Katherine A.; Markley, John L., E-mail: markley@nmrfam.wisc.edu [University of Wisconsin-Madison, National Magnetic Resonance Facility at Madison and Biochemistry Department (United States)

    2016-04-15

    NMR spectroscopy is a powerful technique for determining structural and functional features of biomolecules in physiological solution as well as for observing their intermolecular interactions in real-time. However, complex steps associated with its practice have made the approach daunting for non-specialists. We introduce an NMR platform that makes biomolecular NMR spectroscopy much more accessible by integrating tools, databases, web services, and video tutorials that can be launched by simple installation of NMRFAM software packages or using a cross-platform virtual machine that can be run on any standard laptop or desktop computer. The software package can be downloaded freely from the NMRFAM software download page ( http://pine.nmrfam.wisc.edu/download-packages.html http://pine.nmrfam.wisc.edu/download{sub p}ackages.html ), and detailed instructions are available from the Integrative NMR Video Tutorial page ( http://pine.nmrfam.wisc.edu/integrative.html http://pine.nmrfam.wisc.edu/integrative.html ).

  10. Interpretations of NMR images

    International Nuclear Information System (INIS)

    Shi, J.Z.; McFarland, W.D.; Chen, S.S.; Sadhu, V.K.

    1986-01-01

    Two color display schemes are generally considered in medical images: pseudo-color and color composite. Psuedo-color technique maps the intensity means of a single monochrome image into a three dimensional color space, the gray level is thus replaced by the assigned color. Such a psuedo-color assignment is somewhat arbitrary but may be advantageous if the monochrome image is composed of simple intensity patterns. A good example of psuedo-color application is in nuclear medicine: The change of gray levels can be simply determined and the isocounts from two regions with different surroundings can be readily recognized. However, the use of psuedo-color in CT or MR imaging is controversial because it does not give additional information and may exaggerate insignificant gray scale differences. The color composite technique maps three parametric image data into a three dimensional color space, and thus three monochrome images are merged to form a single color image. The color composite technique increases the number of ways information can be displayed and provides both quantitative and qualitative data about the object or event represented. This paper describes the application of color composite in NMR images

  11. Quantification of Atmospheric N2 Fixed by Cowpea, Pigeonpea and ...

    African Journals Online (AJOL)

    at taking advantage of legumes to replenish soil nitrogen (N due to legumes' N2 fixation). Glasshouse pot ... In both cases, maize (Katumani variety) was the non- N2- fixing reference crop. ... Biological N2 fixation is affected by several factors,.

  12. N-2 fixation by non-heterocystous cyanobacteria

    NARCIS (Netherlands)

    Bergman, B.; Gallon, J.R.; Rai, A.N.; Stal, L.J.

    1997-01-01

    Many, though not all, non-heterocystous cyanobacteria can fix N-2. However, very few strains can fix N-2 aerobically. Nevertheless, these organisms may make a substantial contribution to the global nitrogen cycle. In this general review, N-2 fixation by laboratory cultures and natural populations of

  13. NMR characterization of thin films

    Science.gov (United States)

    Gerald II, Rex E.; Klingler, Robert J.; Rathke, Jerome W.; Diaz, Rocio; Vukovic, Lela

    2010-06-15

    A method, apparatus, and system for characterizing thin film materials. The method, apparatus, and system includes a container for receiving a starting material, applying a gravitational force, a magnetic force, and an electric force or combinations thereof to at least the starting material, forming a thin film material, sensing an NMR signal from the thin film material and analyzing the NMR signal to characterize the thin film of material.

  14. NMR imaging of cerebral infarction

    International Nuclear Information System (INIS)

    Takusagawa, Yoshihiko; Yamaoka, Naoki; Doi, Kazuaki; Okada, Keisei

    1987-01-01

    One hundred and five patients with cerebral infarction were studied by nuclear magnetic resonance (NMR) CT (resistive type of magnet with strength of 0.1 tesla) and X-ray CT. Pulse sequences used saturation recovery (Tr = 600 mSec), Inversion recovery (Tr = 500 mSec, Td = 300 mSec) and spin echo (Tr = 1500 mSec, Te = 40, 80, 120, 160 mSec). Fifteen cases were examined by NMR-CT within 24 hours from onset. Proton NMR imaging could not detect cerebral ischemia as early as 2 hours after onset, but except could detect the lesions in Se image the area of cerebral infarct 3 hours after onset. After 5 hours from onset image changes in SE were evident and corresponded to the area of cerebral infarct, but image changes in IR could not fully delineate the infarcted area. NMR images of 41 year-old woman with cerebral embolism by MCA trunck occlusion associated with mitral stenosis were presented, and NMR-CT was examined 10 hours, 9th and 43th days after episode of MCA occlusion. Sixty patents (64 times) with lacunar infarction were studied by NMR-CT and X-ray CT. The inversion recovery images were used mainly for detection of lesions and comparison with X-ray CT. In 160 lesions which were detected by NMR-CT or X-ray CT, could 156 lesions be detected by NMR-CT and 78 lesions by X-ray CT. Inversion recovery images were more useful for detection of lacunes than X-ray CT. Calculated T1 and T2 values prolonged with time course from onset. (author)

  15. Optical pumping and xenon NMR

    International Nuclear Information System (INIS)

    Raftery, M.D.

    1991-11-01

    Nuclear Magnetic Resonance (NMR) spectroscopy of xenon has become an important tool for investigating a wide variety of materials, especially those with high surface area. The sensitivity of its chemical shift to environment, and its chemical inertness and adsorption properties make xenon a particularly useful NMR probe. This work discusses the application of optical pumping to enhance the sensitivity of xenon NMR experiments, thereby allowing them to be used in the study of systems with lower surface area. A novel method of optically-pumping 129 Xe in low magnetic field below an NMR spectrometer and subsequent transfer of the gas to high magnetic field is described. NMR studies of the highly polarized gas adsorbed onto powdered samples with low to moderate surface areas are now possible. For instance, NMR studies of optically-pumped xenon adsorbed onto polyacrylic acid show that xenon has a large interaction with the surface. By modeling the low temperature data in terms of a sticking probability and the gas phase xenon-xenon interaction, the diffusion coefficient for xenon at the surface of the polymer is determined. The sensitivity enhancement afforded by optical pumping also allows the NMR observation of xenon thin films frozen onto the inner surfaces of different sample cells. The geometry of the thin films results in interesting line shapes that are due to the bulk magnetic susceptibility of xenon. Experiments are also described that combine optical pumping with optical detection for high sensitivity in low magnetic field to observe the quadrupoler evolution of 131 Xe spins at the surface of the pumping cells. In cells with macroscopic asymmetry, a residual quadrupolar interaction causes a splitting in the 131 Xe NMR frequencies in bare Pyrex glass cells and cells with added hydrogen

  16. NMR characterization of thin films

    Science.gov (United States)

    Gerald, II, Rex E.; Klingler, Robert J.; Rathke, Jerome W.; Diaz, Rocio; Vukovic, Lela

    2008-11-25

    A method, apparatus, and system for characterizing thin film materials. The method, apparatus, and system includes a container for receiving a starting material, applying a gravitational force, a magnetic force, and an electric force or combinations thereof to at least the starting material, forming a thin film material, sensing an NMR signal from the thin film material and analyzing the NMR signal to characterize the thin film of material.

  17. Superfield realizations of N=2 super-W3

    International Nuclear Information System (INIS)

    Ivanov, E.; Krivonos, S.

    1992-04-01

    We present a manifestly N=2 supersymmetric formulation of N=2 super-W 3 algebra (its classical version) in terms of the spin 1 and spin 2 supercurrents. Two closely related types of the Feigin-Fuchs representation for these supercurrents are found: via two chiral spin 1/2 superfields generating N=2 extended U(1) Kac-Moody algebras and via two free chiral spin 0 superfields. We also construct a one-parameter family of N=2 super Boussinesq equations for which N=2 super-W 3 provides the second Hamiltonian structure. (author). 17 refs

  18. Renormalizable N=2 supersymmetric and gauge invariant interactions from the N=2 harmonic superspace with central charges

    International Nuclear Information System (INIS)

    Saidi, E.H.

    1986-04-01

    The N=2 harmonic-superspace in the presence of central charges is developed. Renormalizable interactions unusual in N=2 supersymmetric theories, are derived in a consistent way. Symmetries generated by the central charges are discussed. A certain equivalence between N=2 harmonic superspace with and without central charges is established. A non-abelian generalization of the model is given. (author)

  19. New Results in {mathcal {N}}=2 N = 2 Theories from Non-perturbative String

    Science.gov (United States)

    Bonelli, Giulio; Grassi, Alba; Tanzini, Alessandro

    2018-03-01

    We describe the magnetic phase of SU(N) $\\mathcal{N}=2$ Super Yang-Mills theories in the self-dual Omega background in terms of a new class of multi-cut matrix models. These arise from a non-perturbative completion of topological strings in the dual four dimensional limit which engineers the gauge theory in the strongly coupled magnetic frame. The corresponding spectral determinants provide natural candidates for the tau functions of isomonodromy problems for flat spectral connections associated to the Seiberg-Witten geometry.

  20. Medical applications of NMR imaging and NMR spectroscopy with stable isotopes. Summary

    Energy Technology Data Exchange (ETDEWEB)

    Matwiyoff, N.A.

    1983-01-01

    The current status of NMR imaging and NMR spectroscopy are summarized. For the most part examples from the March 1983 Puerto Rico symposium are used to illustrate the utility of NMR in medicine. 18 refs., 5 figs.

  1. Medical applications of NMR imaging and NMR spectroscopy with stable isotopes. Summary

    International Nuclear Information System (INIS)

    Matwiyoff, N.A.

    1983-01-01

    The current status of NMR imaging and NMR spectroscopy are summarized. For the most part examples from the March 1983 Puerto Rico symposium are used to illustrate the utility of NMR in medicine. 18 refs., 5 figs

  2. Estimating N2O processes during grassland renewal and grassland conversion to maize cropping using N2O isotopocules

    Science.gov (United States)

    Buchen, Caroline; Well, Reinhard; Flessa, Heinz; Fuß, Roland; Helfrich, Mirjam; Lewicka-Szczebak, Dominika

    2017-04-01

    Grassland break-up due to grassland renewal and grassland conversion to cropland can lead to a flush of mineral nitrogen from decomposition of the old grass sward and the decomposition of soil organic matter. Moreover, increased carbon and nitrogen mineralisation can result in enhanced nitrous oxide (N2O) emissions. As N2O is known to be an important greenhouse gas and a major precursor for ozone depletion, its emissions need to be mitigated by adjusting agricultural management practices. Therefore, it is necessary to understand the N2O processes involved, as well as the contribution of N2O reduction to N2. Apart from the widely used 15N gas flux method, natural abundance isotopic analysis of the four most abundant isotopocules of N2O species is a promising alternative to assess N2O production pathways. We used stable isotope analyses of soil-emitted N2O (δ18ON2O, δ15NN2Obulk and δ15NN2OSP= intramolecular distribution of 15N within the linear N2O molecule) with an isotopocule mapping approach to simultaneously estimate the magnitude of N2O reduction to N2 and the fraction of N2O originating from the bacterial denitrification pathway or fungal denitrification and/or nitrification. This approach is based on endmember areas of isotopic values for the N2O produced from different sources reported in the literature. For this purpose, we calculated two main scenarios with different assumptions for N2O produced: N2O is reduced to N2 before residual N2O is mixed with N2O of various sources (Scenario a) and vice versa (Scenario b). Based on this, we applied seven different scenario variations, where we evaluated the range of possible values for the potential N2O production pathways (heterotrophic bacterial denitrification and/or nitrifier denitrification and fungal denitrification and/or nitrification). This was done by using a range of isotopic endmember values and assuming different fractionation factors of N2O reduction in order to find the most reliable scenario

  3. Production of N2O in grass-clover pastures

    International Nuclear Information System (INIS)

    Carter, M.S.

    2005-09-01

    Agricultural soils are known to be a considerable source of the strong greenhouse gas nitrous oxide (N 2 O), and in soil N 2 O is mainly produced by nitrifying and denitrifying bacteria. In Denmark, grass-clover pastures are an important component of the cropping system in organic as well as conventional dairy farming, and on a European scale grass-clover mixtures represent a large part of the grazed grasslands. Biological dinitrogen (N 2 ) fixation in clover provides a major N input to these systems, but knowledge is sparse regarding the amount of fixed N 2 lost from the grasslands as N2O. Furthermore, urine patches deposited by grazing cattle are known to be hot-spots of N 2 O emission, but the mechanisms involved in the N 2 O production in urine-affected soil are very complex and not well understood. The aim of this Ph.D. project was to increase the knowledge of the biological and physical-chemical mechanisms, which control the production of N2O in grazed grass-clover pastures. Three experimental studies were conducted with the objectives of: 1: assessing the contribution of recently fixed N 2 as a source of N 2 O. 2: examining the link between N 2 O emission and carbon mineralization in urine patches. 3: investigating the effect of urine on the rates and N 2 O loss ratios of nitrification and denitrification, and evaluating the impact of the chemical conditions that arise in urine affected soil. The results revealed that only 3.2 ± 0.5 ppm of the recently fixed N 2 was emitted as N2O on a daily basis. Thus, recently fixed N released via easily degradable clover residues appears to be a minor source of N2O. Furthermore, increased N 2 O emission following urine application at rates up to 5.5 g N m -2 was not caused by enhanced denitrification stimulated by labile compounds released from scorched plant roots. Finally, the increase of soil pH and ammonium following urine application led to raised nitrification rate, which appeared to be the most important factor

  4. Soil invertebrate fauna affect N2 O emissions from soil.

    Science.gov (United States)

    Kuiper, Imke; de Deyn, Gerlinde B; Thakur, Madhav P; van Groenigen, Jan Willem

    2013-09-01

    Nitrous oxide (N2 O) emissions from soils contribute significantly to global warming. Mitigation of N2 O emissions is severely hampered by a lack of understanding of its main controls. Fluxes can only partly be predicted from soil abiotic factors and microbial analyses - a possible role for soil fauna has until now largely been overlooked. We studied the effect of six groups of soil invertebrate fauna and tested the hypothesis that all of them increase N2 O emissions, although to different extents. We conducted three microcosm experiments with sandy soil and hay residue. Faunal groups included in our experiments were as follows: fungal-feeding nematodes, mites, springtails, potworms, earthworms and isopods. In experiment I, involving all six faunal groups, N2 O emissions declined with earthworms and potworms from 78.4 (control) to 37.0 (earthworms) or 53.5 (potworms) mg N2 O-N m(-2) . In experiment II, with a higher soil-to-hay ratio and mites, springtails and potworms as faunal treatments, N2 O emissions increased with potworms from 51.9 (control) to 123.5 mg N2 O-N m(-2) . Experiment III studied the effect of potworm density; we found that higher densities of potworms accelerated the peak of the N2 O emissions by 5 days (P soil aeration by the soil fauna reduced N2 O emissions in experiment I, whereas in experiment II N2 O emissions were driven by increased nitrogen and carbon availability. In experiment III, higher densities of potworms accelerated nitrogen and carbon availability and N2 O emissions, but did not increase them. Overall, our data show that soil fauna can suppress, increase, delay or accelerate N2 O emissions from soil and should therefore be an integral part of future N2 O studies. © 2013 John Wiley & Sons Ltd.

  5. Carbon-13 NMR of flavinoids

    International Nuclear Information System (INIS)

    Agrawal, P.K.

    1989-01-01

    The present book has been written with the objective of introducing the organic chemists with the conceptual and experimental basis required for interpretation of 13 C NMR spectra of a flavonoid and to a discussion of general usefulness of the technique in solving flavonoid structural problem. After a brief general introduction to the essential aspects of flavonoids and 13 C NMR spectroscopy, considerable emphasis has been placed in chapter 2 on the various experimental methods and the interpretation of spectral details which enable individual resonance lines to be associated with the appropriate carbons in a molecule. The whole bulk of the literature, published on 13 C NMR of flavonoids in the major journals upto 1986 alongwith some recent references of 1987 has been classified in several categories such as: flavonoids, isflavonoids, other flavonoids, flavonoid glycosides, chalconoids and flavanoids. Each category constitutes a chapter. Finally the last chapter is devoted largely to a discussion for the differentiation of various categories and subcategories of flavonoids and for the establishment of aromatic substitution pattern in these compounds. It should be emphasized that the book is a data book and only concerned with the actual analysis of 13 C NMR spectra, thus a reasonable familiarity with basic instrumentation of 13 C NMR and general pattern of nuclear chemical shifts has been assumed. (author). refs.; figs.; tabs

  6. Greenhouse gas (N2O emission from Portuguese estuaries

    Directory of Open Access Journals (Sweden)

    Célia Gonçalves

    2014-07-01

    Tagus, Minho and Lima estuaries are source of N2O to the atmosphere. Particularly, in Lima estuary anthropogenic N input seems to play an important role on N2O emission. However, in a global perspective N2O attained emissions represent a reduced fraction (2O yr-1, Barnes and Upstill-Goddard, 2011. Values are comparable with those registered in some Portuguese estuaries and other European less eutrophic estuaries. However, it is known that higher N2O emissions in estuaries may occur during winter and spring (Sun et al., 2014. Thus, these systems may represent on an annual basis a larger source of N2O, which can only be clarified in future studies. Only a full comprehension of the global estuarine nitrogen cycle will provide an efficient basis of scientific knowledge for sustainably management of such ecosystems and ultimately reduce N2O emissions.

  7. NMR investigation of coal extracts

    Energy Technology Data Exchange (ETDEWEB)

    Lang, I; Sebor, G [Ceskoslovenska Akademie Ved, Prague. Hornicky Ustav; Sebor, G Jr; Hajek, M; Mostecky, J [Vysoka Skola Chemicko-Technologicka, Prague (Czechoslovakia)

    1978-07-01

    Proton NMR spectroscopy was used for the evaluation of 10% coal extract solutions in deuterated pyridine. Four types of Czechoslovak coal were analyzed. Agreement was found between the aromaticity of coal extracts calculated from /sup 1/H NMR data using Brown's method and Ladner's and Williams' method and the characterization of an average molecule of the coal extract by the number of non-bridge carbon atoms of aromatic rings, by the overall number of aromatic ring carbon atoms and the number of aromatic rings, determined by the Williams and Ferris methods. The methods for calculating carbon distribution from /sup 1/H NMR data, however, contain some constants theoretically estimated or experimentally found using the method which still remain to be verified.

  8. Dissolution and Release of Gaseous Nitrogen (N2, N2O) in the Source Region of the Yellow River

    Science.gov (United States)

    Zhang, L.; Xia, X.; Wang, J.

    2017-12-01

    Nitrogen is an important biogenic element. The migration and transformation of nitrogen in rivers is an important process affecting global nitrogen cycling and greenhouse gas emissions. However, there is a lack of research on nitrogen removal and greenhouse gas emission characteristics of high altitude rivers. In this work, the spatial and temporal variations of dissolved nitrogen (N2 and N2O) concentrations, saturation, and release flux as well as their responses to environmental factors were studied in the Yellow River source area, a typical high altitude river. The results showed that the dissolved concentrations of N2 and N2O in the rivers were 8.24-137.75 μmol.L-1 and 2.57-31.94 nmol.L-1, respectively. N2 and N2O saturation were greater than 100% for all the sampling sites, indicating that the river is a release source for atmosphere N2 and N2O. Correspondingly, the fluxes of N2 and N2O from river water to atmosphere were 24.12-1606.57 mmol (m2.d) -1 and 12.96-276.81 μmol (m2.d) -1, respectively. Generally, the dissolution concentration and release flux of N2 and N2O in July were larger than that in May. The concentrations of N2 and N2O in river water were related to the environmental factors, and the dissolved concentration of N2 in the surface water was significantly positively correlated with water temperature, NH4+-N and total inorganic nitrogen (DIN) (p<0.01). The dissolved concentration of N2O was significantly positively correlated with the content of suspended particulates, DO, and DIN (p<0.01). Thus, DIN is a key factor in the process of N2 and N2O formation. This study can help to understand the nitrogen cycling in high-altitude rivers and provide basic data for a comprehensive assessment of global river nitrogen loss. Key Words: Source Region of the Yellow River; Gaseous Nitrogen; Nitrogen loss; High altitude river

  9. Spectroscopic studies, antimicrobial activities and crystal structures of N-(2-hydroxy-3-methoxybenzalidene)1-aminonaphthalene

    Science.gov (United States)

    Ünver, Hüseyin; Yıldız, Mustafa; Dülger, Başaran; Özgen, Özen; Kendi, Engin; Durlu, Tahsin Nuri

    2005-03-01

    Schiff base N-(2-hydroxy-3-methoxybenzalidene)1-aminonaphthalene has been synthesized from the reaction of 2-hydroxy-3-methoxybenzaldehyde with 1-aminonaphthalene. The compound were characterized by elemental analysis, FT-IR, 1H NMR, 13C NMR and UV-visible techniques. The UV-visible spectra of the Schiff base were studied in polar and nonpolar solvents in acidic and basic media. The structure of the compound has been examined cyrstallographically. There are two independent molecules in the asymmetric unit. It crystallizes in the monoclinic space group P21/c, with unit cell parameters: a=14, 602(2), b=5,800(1), c=16, 899(1) Å, V=1394.4(2) Å 3, Dx=1.321 g cm -3 and Z=4. The crystal structure was solved by direct methods and refined by full-matrix least squares to a find R=0.041 of for 1179 observed reflections. The title compound's antimicrobial activities also have been studied. The antimicrobial activities of the ligand has been screened in vitro against the organisms Escherichia coli ATCC 11230, Staphylococcus aureus ATCC 6538, Klebsiella pneumoniae UC57, Micrococcus luteus La 2971, Proteus vulgaris ATCC 8427, Pseudomonas aeruginosa ATCC 27853, Mycobacterium smegmatis CCM 2067, Bacillus cereus ATCC 7064 and Listeria monocytogenes ATCC 15313, the yeast cultures Candida albicans ATCC 10231, Kluyveromyces fragilis NRRL 2415, Rhodotorula rubra DSM 70403, Debaryomyces hansenii DSM 70238 and Hanseniaspora guilliermondii DSM 3432.

  10. N2O emission under fluidized bed combustion condition

    International Nuclear Information System (INIS)

    Shen, B.X.; Yao, Q.; Mi, T.; Liu, D.C.; Feng, B.; Winter, Franz

    2003-01-01

    In this paper, many rules about N 2 O and NO x emission under fluidized bed combustion conditions were found by experiments. The research results indicate that CaO, CaSO 4 , Fe 2 O 3 and char have important influence on decomposition of N 2 O; co-combustion of coal and biomass are effective measures to low N 2 O and NO x emission

  11. The structure of N = 2 supergravity in N = 1 superfields

    International Nuclear Information System (INIS)

    Awada, M.A.; Mokhtari, S.

    1985-01-01

    A formulation of N = 2 supergravity in N = 1 superspace is presented. The authors solve up to all orders the N = 2 supergravity constraints in terms of unconstrained N = 1 superfields. The structure of the N = 2 action in N = 1 superspace is examined. The proposed action coincides in the quadratic limit of the spin (3/2,1) matter fields with the action given by previous workers. (author)

  12. Structure of N = 2 supergravity in N = 1 superfields

    Energy Technology Data Exchange (ETDEWEB)

    Awada, M.A.; Mokhtari, S. (Imperial Coll. of Science and Technology, London (UK). Blackett Lab.)

    1985-01-01

    A formulation of N = 2 supergravity in N = 1 superspace is presented. The authors solve up to all orders the N = 2 supergravity constraints in terms of unconstrained N = 1 superfields. The structure of the N = 2 action in N = 1 superspace is examined. The proposed action coincides in the quadratic limit of the spin (3/2,1) matter fields with the action given by previous workers.

  13. NOx and N2O emission control with catalyst's

    International Nuclear Information System (INIS)

    Hiltunen, M.

    1994-01-01

    Due to the increasingly stringent emission regulations, new technologies are needed to be developed for improving emission control in circulating fluidized-bed boilers. The objective of this project is to test the concept of using catalysts for NO x and N 2 O emission control. N 2 O emission is in the range of 30 - 100 ppm from fluidized bed combustors burning coal. Since it is a greenhouse gas an effective means of controlling N 2 O emission is needed

  14. Stratospheric concentrations of N2O in July 1975

    International Nuclear Information System (INIS)

    Krey, P.W.; Lagomarsino, R.J.; Schonberg, M.

    1977-01-01

    The first measurement of the hemispheric distribution of N 2 O concentrations in the lower stratosphere of the Northern Hemisphere is reported for July 1975. This distribution is similar to those of CCl 3 F and SF 6 , although N 2 O is more stable in the stratosphere than either of the other trace gases. The inventory of N 2 O in the stratosphere of the Northern Hemisphere in July 1975 against which future observations can be compared is 136 Tg

  15. A quantum chemical study of the N2H+ + e- → N2 + H reaction I: The linear dissociation path

    International Nuclear Information System (INIS)

    Talbi, D.

    2007-01-01

    A theoretical investigation of the dissociative recombination (DR) of linear N 2 H + (X 1 Σ g + ) to give N 2 + H has been undertaken because it is of interest for astrochemistry and also because it has been recently studied experimentally. Using state of the art quantum chemical methods, it is shown that the lowest 2 Σ repulsive state of N 2 H leading to the N 2 and H fragments in their ground electronic states does not cross the curve of the ion nor the one of the lowest N 2 H Rydberg state. This lowest 2 Σ repulsive state is very low in energy. Its curve passes below the 1 Σ N 2 H + state and below the lowest bound 2 Σ N 2 H states. However, it is also shown that there exist higher repulsive 2 Σ and 2 Δ states of N 2 H (the second and third repulsive states) crossing the ion curve. These states will lead to the formation of N 2 in its 3 Σ u + and 3 Δ u states. This study, the first of its type, shows that the DR of linear N 2 H + should involve the direct mechanism and that it should lead to N 2 in its first excited states. However this process may not be efficient for N 2 H + in its ground vibrational state (v = 0), a state in which it exists in the cold environment of the interstellar medium. For the DR to be efficient for N 2 H + in its ground v = 0 vibrational state, bent geometries of the ion might have to be considered

  16. Nitrous oxide (N2O) emission from aquaculture: a review.

    Science.gov (United States)

    Hu, Zhen; Lee, Jae Woo; Chandran, Kartik; Kim, Sungpyo; Khanal, Samir Kumar

    2012-06-19

    Nitrous oxide (N(2)O) is an important greenhouse gas (GHG) which has a global warming potential 310 times that of carbon dioxide (CO(2)) over a hundred year lifespan. N(2)O is generated during microbial nitrification and denitrification, which are common in aquaculture systems. To date, few studies have been conducted to quantify N(2)O emission from aquaculture. Additionally, very little is known with respect to the microbial pathways through which N(2)O is formed in aquaculture systems. This review suggests that aquaculture can be an important anthropogenic source of N(2)O emission. The global N(2)O-N emission from aquaculture in 2009 is estimated to be 9.30 × 10(10) g, and will increase to 3.83 × 10(11)g which could account for 5.72% of anthropogenic N(2)O-N emission by 2030 if the aquaculture industry continues to increase at the present annual growth rate (about 7.10%). The possible mechanisms and various factors affecting N(2)O production are summarized, and two possible methods to minimize N(2)O emission, namely aquaponic and biofloc technology aquaculture, are also discussed. The paper concludes with future research directions.

  17. N2O production, a widespread trait in fungi

    Science.gov (United States)

    Maeda, Koki; Spor, Aymé; Edel-Hermann, Véronique; Heraud, Cécile; Breuil, Marie-Christine; Bizouard, Florian; Toyoda, Sakae; Yoshida, Naohiro; Steinberg, Christian; Philippot, Laurent

    2015-04-01

    N2O is a powerful greenhouse gas contributing both to global warming and ozone depletion. While fungi have been identified as a putative source of N2O, little is known about their production of this greenhouse gas. Here we investigated the N2O-producing ability of a collection of 207 fungal isolates. Seventy strains producing N2O in pure culture were identified. They were mostly species from the order Hypocreales order--particularly Fusarium oxysporum and Trichoderma spp.--and to a lesser extent species from the orders Eurotiales, Sordariales, and Chaetosphaeriales. The N2O 15N site preference (SP) values of the fungal strains ranged from 15.8‰ to 36.7‰, and we observed a significant taxa effect, with Penicillium strains displaying lower SP values than the other fungal genera. Inoculation of 15 N2O-producing strains into pre-sterilized arable, forest and grassland soils confirmed the ability of the strains to produce N2O in soil with a significant strain-by-soil effect. The copper-containing nitrite reductase gene (nirK) was amplified from 45 N2O-producing strains, and its genetic variability showed a strong congruence with the ITS phylogeny, indicating vertical inheritance of this trait. Taken together, this comprehensive set of findings should enhance our knowledge of fungi as a source of N2O in the environment.

  18. Two-dimensional NMR spectrometry

    International Nuclear Information System (INIS)

    Farrar, T.C.

    1987-01-01

    This article is the second in a two-part series. In part one (ANALYTICAL CHEMISTRY, May 15) the authors discussed one-dimensional nuclear magnetic resonance (NMR) spectra and some relatively advanced nuclear spin gymnastics experiments that provide a capability for selective sensitivity enhancements. In this article and overview and some applications of two-dimensional NMR experiments are presented. These powerful experiments are important complements to the one-dimensional experiments. As in the more sophisticated one-dimensional experiments, the two-dimensional experiments involve three distinct time periods: a preparation period, t 0 ; an evolution period, t 1 ; and a detection period, t 2

  19. Solid state NMR of materials

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Sharon A; Ferguson, David B; Haw, James F [Texas A and M Univ., College Station, TX (United States). Dept. of Chemistry

    1994-12-31

    In situ NMR experiments are studied, including probe of several structures such as the structures of the organic adsorbates, Broensted acid sites, other nuclei associated with active sites, and other framework sites. The authors report that in the absence of high concentrations of paramagnetic sites or metal particles, high resolution MAS spectra are relatively easy to obtain and interpret. It is also concluded that NMR can measure spatial distributions and rates of diffusion; and are able to characterize equilibrium structures and the frequencies and amplitudes of molecular motion

  20. Push-through Direction Injectin NMR Automation

    Science.gov (United States)

    Nuclear magnetic resonance (NMR) and mass spectrometry (MS) are the two major spectroscopic techniques successfully used in metabolomics studies. The non-invasive, quantitative and reproducible characteristics make NMR spectroscopy an excellent technique for detection of endogeno...

  1. Fourier transform n.m.r. spectroscopy

    International Nuclear Information System (INIS)

    Shaw, D.

    1976-01-01

    This book is orientated to techniques rather than applications. The basic theory of n.m.r. is dealt with in a unified approach to the Fourier theory. The middle section of the book concentrates on the practical aspects of Fourier n.m.r., both instrumental and experimental. The final chapters briefly cover general application of n.m.r., but concentrate strongly on those areas where Fourier n.m.r. can give information which is not available by conventional techniques

  2. Soil invertebrate fauna affect N2O emissions from soil

    NARCIS (Netherlands)

    Kuiper, I.; Deyn, de G.B.; Thakur, M.P.; Groenigen, van J.W.

    2013-01-01

    Nitrous oxide (N2O) emissions from soils contribute significantly to global warming. Mitigation of N2O emissions is severely hampered by a lack of understanding of its main controls. Fluxes can only partly be predicted from soil abiotic factors and microbial analyses – a possible role for soil fauna

  3. Comparative Effects of Cowpea and Soybean Genotypes on N2 ...

    African Journals Online (AJOL)

    acer

    ABSTRACT:A field trial was conducted to asses N2 - fixation and N balance in five cultivars each of soybean (TGX 1945 – 1F, ... Key words: Legume genotype, N2 fixation, N balance and Nitrogen Harvest Index (NHI) ..... subsequent maize grain yield in the guinea savanna ... On-farm evaluation of biological nitrogen fixation.

  4. One-instanton calculations in N=2 supersymmetric gauge theories

    International Nuclear Information System (INIS)

    Ito, Katsushi

    1998-01-01

    We study the low-energy effective action of N=2 supersymmetric gauge theories in the Coulomb branch. Using microscopic instanton calculus, we compute the one-instanton contribution to the pre potential for N=2 supersymmetric SU(N c ) Yang-Mills theory. We show that the microscopic result agrees with the exact solution. (Author). 23 refs

  5. Nitrous Oxide (N2O) Emissions from Vehicles

    International Nuclear Information System (INIS)

    Becker, K.H.; Kurtenbach, R.; Lorzer, J.C.; Wiesen, P.; Jensen, T.; Wallington, T.J.

    2000-01-01

    N2O is an important greenhouse gas and accurate emission data are required to assess its impact on global climate. It is well established that automobiles, particularly those equipped with 3-way catalysts, emit N2O. However, the vehicle contribution to the global N2O budget is uncertain. We report results of N2O emission measurements performed in a road tunnel in Germany and using a chassis dynamometer system in the USA. We estimate that the global vehicle fleet emits (0.12±0.06) Tg yr-1 of N2O. From the emission factor (g N2O/g CO2) determined an annual N2O emission of (0.12±0.06) Tg yr-1 of N2O (0.08±0.04 Tg N yr-1) for the global vehicle fleet has been estimated which represents 1-4% of the atmospheric growth rate of this species. 9 refs

  6. NMR investigations of molecular dynamics

    Science.gov (United States)

    Palmer, Arthur

    2011-03-01

    NMR spectroscopy is a powerful experimental approach for characterizing protein conformational dynamics on multiple time scales. The insights obtained from NMR studies are complemented and by molecular dynamics (MD) simulations, which provide full atomistic details of protein dynamics. Homologous mesophilic (E. coli) and thermophilic (T. thermophilus) ribonuclease H (RNase H) enzymes serve to illustrate how changes in protein sequence and structure that affect conformational dynamic processes can be monitored and characterized by joint analysis of NMR spectroscopy and MD simulations. A Gly residue inserted within a putative hinge between helices B and C is conserved among thermophilic RNases H, but absent in mesophilic RNases H. Experimental spin relaxation measurements show that the dynamic properties of T. thermophilus RNase H are recapitulated in E. coli RNase H by insertion of a Gly residue between helices B and C. Additional specific intramolecular interactions that modulate backbone and sidechain dynamical properties of the Gly-rich loop and of the conserved Trp residue flanking the Gly insertion site have been identified using MD simulations and subsequently confirmed by NMR spin relaxation measurements. These results emphasize the importance of hydrogen bonds and local steric interactions in restricting conformational fluctuations, and the absence of such interactions in allowing conformational adaptation to substrate binding.

  7. PSYCHE Pure Shift NMR Spectroscopy.

    Science.gov (United States)

    Foroozandeh, Mohammadali; Morris, Gareth; Nilsson, Mathias

    2018-03-13

    Broadband homodecoupling techniques in NMR, also known as "pure shift" methods, aim to enhance spectral resolution by suppressing the effects of homonuclear coupling interactions to turn multiplet signals into singlets. Such techniques typically work by selecting a subset of "active" nuclear spins to observe, and selectively inverting the remaining, "passive", spins to reverse the effects of coupling. Pure Shift Yielded by Chirp Excitation (PSYCHE) is one such method; it is relatively recent, but has already been successfully implemented in a range of different NMR experiments. Paradoxically, PSYCHE is one of the trickiest of pure shift NMR techniques to understand but one of the easiest to use. Here we offer some insights into theoretical and practical aspects of the method, and into the effects and importance of the experimental parameters. Some recent improvements that enhance the spectral purity of PSYCHE spectra will be presented, and some experimental frameworks including examples in 1D and 2D NMR spectroscopy, for the implementation of PSYCHE will be introduced. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. N2O Emission from energy crop fields

    International Nuclear Information System (INIS)

    Joergensen, B.J.; Nyholm Joergensen, R.

    1996-03-01

    The interest in N 2 O emissions from soils with energy crops is a results of its properties as a greenhouse gas, since the global warming potential of N 2 O per unit mass is about 320 times greater than CO 2 . The contribution of N 2 O from the soil to the atmosphere may increase due to agricultural management. Consequently, large N 2 O emissions can lower the reduction of the greenhouse effect achieved by the substitution of fossil fuels by energy crops. For this reason it is crucial to find the crops for combustion with the lowest potential for emission of N 2 O from the soil per produced energy unit. The aims of this study were to assess the annual N 2 O flux from a Miscanthus 'Giganteus' (M. 'Giganteus') and winter rye (Secale cereale) field, and to investigate the factors affecting the N 2 O emission. To obtain these aims a method was developed for measurements in tall crops. The thesis contains a literature review on the N 2 O emission from the soils, a section with development of the technique for N 2 O flux measurements, and an experimental section. Finally, the thesis contains a section where the results are discussed in relation to the use of energy crops. In all the filed studies, the N 2 O emission was measured by using a new developed closed-chamber technique. The main advantages of the chamber method were the ability to contain growing plants up to a height of 3 m, and the relatively large area (2X2m) covered by each other. Soils with annual and perennial crops can be expected to emit less then 3 kg N 2 O ha -1 yr -1 . This amount corresponds to 960 kg CO 2 ha -1 yr -1 compared to a total CO 2 reduction of 10 to 19 tons CO 2 ha -1 yr -1 using the energy crops as substitution for fossil fuels. An efficient way to reduce the N 2 O emission is to exclude use of fertiliser but this also reduces the dry matter yield and consequently also the CO 2 reduction per unit dry matter. Following the guidelines for good agricultural practice concerning the

  9. Heat capacity and thermodynamic properties of N-(2-cyanoethyl) aniline (C9H10N2)

    International Nuclear Information System (INIS)

    Tian Qifeng; Tan Zhicheng; Shi Quan; Xu Fen; Sun Lixian; Zhang Tao

    2005-01-01

    The low temperature heat capacities of N-(2-cyanoethyl)aniline were measured with an automated adiabatic calorimeter over the temperature range from 83 to 353 K. The temperature corresponding to the maximum value of the apparent heat capacity in the fusion interval, molar enthalpy and entropy of fusion of this compound were determined to be 323.33 ± 0.13 K, 19.4 ± 0.1 kJ mol -1 and 60.1 ± 0.1 J K -1 mol -1 , respectively. Using the fractional melting technique, the purity of the sample was determined to be 99.0 mol% and the melting temperature for the tested sample and the absolutely pure compound were determined to be 323.50 and 323.99 K, respectively. A solid-to-solid phase transition occurred at 310.63 ± 0.15 K. The molar enthalpy and molar entropy of the transition were determined to be 980 ± 5 J mol -1 and 3.16 ± 0.02 J K -1 mol -1 , respectively. The thermodynamic functions of the compound [H T - H 298.15 ] and [S T - S 298.15 ] were calculated based on the heat capacity measurements in the temperature range of 83-353 K with an interval of 5 K

  10. UV-induced N2O emission from plants

    Science.gov (United States)

    Bruhn, Dan; Albert, Kristian R.; Mikkelsen, Teis N.; Ambus, Per

    2014-12-01

    Nitrous oxide (N2O) is an important long-lived greenhouse gas and precursor of stratospheric ozone-depleting mono-nitrogen oxides. The atmospheric concentration of N2O is persistently increasing; however, large uncertainties are associated with the distinct source strengths. Here we investigate for the first time N2O emission from terrestrial vegetation in response to natural solar ultra violet radiation. We conducted field site measurements to investigate N2O atmosphere exchange from grass vegetation exposed to solar irradiance with and without UV-screening. Further laboratory tests were conducted with a range of species to study the controls and possible loci of UV-induced N2O emission from plants. Plants released N2O in response to natural sunlight at rates of c. 20-50 nmol m-2h-1, mostly due to the UV component. The emission response to UV-A is of the same magnitude as that to UV-B. Therefore, UV-A is more important than UV-B given the natural UV-spectrum at Earth's surface. Plants also emitted N2O in darkness, although at reduced rates. The emission rate is temperature dependent with a rather high activation energy indicative for an abiotic process. The prevailing zone for the N2O formation appears to be at the very surface of leaves. However, only c. 26% of the UV-induced N2O appears to originate from plant-N. Further, the process is dependent on atmospheric oxygen concentration. Our work demonstrates that ecosystem emission of the important greenhouse gas, N2O, may be up to c. 30% higher than hitherto assumed.

  11. Electrochemical Reduction of N2 under Ambient Conditions for Artificial N2 Fixation and Renewable Energy Storage Using N2 /NH3 Cycle.

    Science.gov (United States)

    Bao, Di; Zhang, Qi; Meng, Fan-Lu; Zhong, Hai-Xia; Shi, Miao-Miao; Zhang, Yu; Yan, Jun-Min; Jiang, Qing; Zhang, Xin-Bo

    2017-01-01

    Using tetrahexahedral gold nanorods as a heterogeneous electrocatalyst, an electrocatalytic N 2 reduction reaction is shown to be possible at room temperature and atmospheric pressure, with a high Faradic efficiency up to 4.02% at -0.2 V vs reversible hydrogen electrode (1.648 µg h -1 cm -2 and 0.102 µg h -1 cm -2 for NH 3 and N 2 H 4 ·H 2 O, respectively). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. The N2HDM under theoretical and experimental scrutiny

    Energy Technology Data Exchange (ETDEWEB)

    Mühlleitner, Margarete [Institute for Theoretical Physics, Karlsruhe Institute of Technology, 76128 Karlsruhe (Germany); Sampaio, Marco O.P. [Departamento de Física, Universidade de Aveiro and CIDMA, Campus de Santiago, 3810-183 Aveiro (Portugal); Santos, Rui [ISEL - Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, 1959-007 Lisboa (Portugal); Centro de Física Teórica e Computacional, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, Edifício C8, 1749-016 Lisboa (Portugal); Wittbrodt, Jonas [Institute for Theoretical Physics, Karlsruhe Institute of Technology, 76128 Karlsruhe (Germany); Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, D-22607 Hamburg (Germany)

    2017-03-17

    The N2HDM is based on the CP-conserving 2HDM extended by a real scalar singlet field. Its enlarged parameter space and its fewer symmetry conditions as compared to supersymmetric models allow for an interesting phenomenology compatible with current experimental constraints, while adding to the 2HDM sector the possibility of Higgs-to-Higgs decays with three different Higgs bosons. In this paper the N2HDM is subjected to detailed scrutiny. Regarding the theoretical constraints we implement tests of tree-level perturbativity and vacuum stability. Moreover, we present, for the first time, a thorough analysis of the global minimum of the N2HDM. The model and the theoretical constraints have been implemented in ScannerS, and we provide N2HDECAY, a code based on HDECAY, for the computation of the N2HDM branching ratios and total widths including the state-of-the-art higher order QCD corrections and off-shell decays. We then perform an extensive parameter scan in the N2HDM parameter space, with all theoretical and experimental constraints applied, and analyse its allowed regions. We find that large singlet admixtures are still compatible with the Higgs data and investigate which observables will allow to restrict the singlet nature most effectively in the next runs of the LHC. Similarly to the 2HDM, the N2HDM exhibits a wrong-sign parameter regime, which will be constrained by future Higgs precision measurements.

  13. The N2HDM under theoretical and experimental scrutiny

    International Nuclear Information System (INIS)

    Mühlleitner, Margarete; Sampaio, Marco O.P.; Santos, Rui; Wittbrodt, Jonas

    2017-01-01

    The N2HDM is based on the CP-conserving 2HDM extended by a real scalar singlet field. Its enlarged parameter space and its fewer symmetry conditions as compared to supersymmetric models allow for an interesting phenomenology compatible with current experimental constraints, while adding to the 2HDM sector the possibility of Higgs-to-Higgs decays with three different Higgs bosons. In this paper the N2HDM is subjected to detailed scrutiny. Regarding the theoretical constraints we implement tests of tree-level perturbativity and vacuum stability. Moreover, we present, for the first time, a thorough analysis of the global minimum of the N2HDM. The model and the theoretical constraints have been implemented in ScannerS, and we provide N2HDECAY, a code based on HDECAY, for the computation of the N2HDM branching ratios and total widths including the state-of-the-art higher order QCD corrections and off-shell decays. We then perform an extensive parameter scan in the N2HDM parameter space, with all theoretical and experimental constraints applied, and analyse its allowed regions. We find that large singlet admixtures are still compatible with the Higgs data and investigate which observables will allow to restrict the singlet nature most effectively in the next runs of the LHC. Similarly to the 2HDM, the N2HDM exhibits a wrong-sign parameter regime, which will be constrained by future Higgs precision measurements.

  14. Uncertainties in United States agricultural N2O emissions: comparing forward model simulations to atmospheric N2O data.

    Science.gov (United States)

    Nevison, C. D.; Saikawa, E.; Dlugokencky, E. J.; Andrews, A. E.; Sweeney, C.

    2014-12-01

    Atmospheric N2O concentrations have increased from 275 ppb in the preindustrial to about 325 ppb in recent years, a ~20% increase with important implications for both anthropogenic greenhouse forcing and stratospheric ozone recovery. This increase has been driven largely by synthetic fertilizer production and other perturbations to the global nitrogen cycle associated with human agriculture. Several recent regional atmospheric inversion studies have quantified North American agricultural N2O emissions using top-down constraints based on atmospheric N2O data from the National Oceanic and Atmospheric Administration (NOAA) Global Greenhouse Gas Reference Network, including surface, aircraft and tall tower platforms. These studies have concluded that global N2O inventories such as EDGAR may be underestimating the true U.S. anthropogenic N2O source by a factor of 3 or more. However, simple back-of-the-envelope calculations show that emissions of this magnitude are difficult to reconcile with the basic constraints of the global N2O budget. Here, we explore some possible reasons why regional atmospheric inversions might overestimate the U.S. agricultural N2O source. First, the seasonality of N2O agricultural sources is not well known, but can have an important influence on inversion results, particularly when the inversions are based on data that are concentrated in the spring/summer growing season. Second, boundary conditions can strongly influence regional inversions but the boundary conditions used may not adequately account for remote influences on surface data such as the seasonal stratospheric influx of N2O-depleted air. We will present a set of forward model simulations, using the Community Land Model (CLM) and two atmospheric chemistry tracer transport models, MOZART and the Whole Atmosphere Community Climate Model (WACCM), that examine the influence of terrestrial emissions and atmospheric chemistry and dynamics on atmospheric variability in N2O at U.S. and

  15. Five Novel Selection Policies for N2R Network Structures

    DEFF Research Database (Denmark)

    Pedersen, Jens Myrup; Riaz, Muhammad Tahir; Madsen, Ole Brun

    2006-01-01

    This paper shows how 5 new selection policies can be applied to N2R structures. For each number of nodes, a selection policy determines which topology is chosen. Compared to approaches taken previously, the policies proposed in this paper allow us to choose structures which are significantly easi...... to implement, while having only slightly longer distances. The 5 policies reflect different trade-offs between distances and ease of implementation, and two of them explore the potentials of using N2R(p; q; r) instead of N2R(p; q) structures....

  16. UV-induced N2O emission from plants

    DEFF Research Database (Denmark)

    Bruhn, Dan; Albert, Kristian Rost; Mikkelsen, Teis Nørgaard

    2014-01-01

    investigate for the fi rst time N 2 O emission from terrestrial vegetation in response to natural solar ultra violet radiation. We conducted fi eld site measurements to investigate N 2 O atmosphere exchange from grass vegetation exposed to solar irradiance with and without UV-screening. Further laboratory...... magnitude as that to UV-B. Therefore, UV-A is more important than UV-B given the natural UV-spectrum at Earth's surface. Plants also emitted N 2 O in darkness, although at reduced rates. The emission rate is temperature dependent with a rather high activation energy indicative for an abiotic process...

  17. N=2 central charge bounds from 2d chiral algebras

    Energy Technology Data Exchange (ETDEWEB)

    Lemos, Madalena [DESY Hamburg, Theory Group,Notkestrasse 85, D-22607 Hamburg (Germany); Liendo, Pedro [IMIP, Humboldt-Universität zu Berlin, IRIS Adlershof,Zum Großen Windkanal 6, 12489 Berlin (Germany)

    2016-04-01

    We study protected correlation functions in N=2 SCFT whose description is captured by a two-dimensional chiral algebra. Our analysis implies a new analytic bound for the c-anomaly as a function of the flavor central charge k, valid for any theory with a flavor symmetry. Combining our result with older bounds in the literature puts strong constraints on the parameter space of N=2 theories. In particular, it singles out a special set of models whose value of c is uniquely fixed once k is given. This set includes the canonical rank one N=2 SCFTs given by Kodaira’s classification.

  18. A heterotic N=2 string with space-time supersymmetry

    International Nuclear Information System (INIS)

    Bellucci, S.; Galajinsky, A.; Lechtenfeld, O.

    2001-02-01

    It is reconsidered the issue of embedding space-time fermions into the four dimensional N=2 world-sheet supersymmetric string. A new heterotic theory is constructed, taking the right-movers from the N =4 topological extension of the conventional N=2 string but a c=0 conformal field theory supporting target-space supersymmetry for the left-moving sector. The global bosonic symmetry of the full formalism proves to be U(1,1), just as in the usual N=2 string. Quantization reveals a spectrum of only two physical states, one boson and one fermion, which fall in a multiplet of (1,0) supersymmetry

  19. Multidimensional effects on dissociation of N-2 on Ru(0001)

    DEFF Research Database (Denmark)

    Diaz, C.; Vincent, J.K.; Krishnamohan, G.P.

    2006-01-01

    on density functional theory. The computed reaction probabilities are in good agreement with molecular beam experiments. Comparison to previous calculations shows that the rotation of N-2 and its motion along the surface affect the reactivity of N-2 much more than nonadiabatic effects.......The applicability of the Born-Oppenheimer approximation to molecule-metal surface reactions is presently a topic of intense debate. We have performed classical trajectory calculations on a prototype activated dissociation reaction, of N-2 on Ru(0001), using a potential energy surface based...

  20. Stress-tensor OPE in N=2 superconformal theories

    International Nuclear Information System (INIS)

    Liendo, Pedro; Ramírez, Israel; Seo, Jihye

    2016-01-01

    We carry out a detailed superspace analysis of the OPE of two N=2 stress-tensor multiplets. Knowledge of the multiplets appearing in the expansion, together with the two-dimensional chiral algebra description of N=2 SCFTs, imply an analytic bound on the central charge c. This bound is valid for any N=2 SCFT regardless of its matter content and flavor symmetries, and is saturated by the simplest Argyres-Douglas fixed point. We also present a partial conformal block analysis for the scalar superconformal primary of the multiplet.

  1. Stress-tensor OPE in N=2 superconformal theories

    International Nuclear Information System (INIS)

    Liendo, Pedro; Ramirez, Israel; Univ. Tecnica Federico Santa Maria, Valparaiso; Seo, Jihye

    2015-11-01

    We carry out a detailed superspace analysis of the OPE of two N=2 stress-tensor multiplets. Knowledge of the multiplets appearing in the expansion, together with the two-dimensional chiral algebra description of N=2 SCFTs, imply an analytic bound on the central charge c. This bound is valid for any N=2 SCFT regardless of its matter content and flavor symmetries, and is saturated by the simplest Argyres-Douglas fixed point. We also present a partial conformal block analysis for the scalar superconformal primary of the multiplet.

  2. High resolution NMR theory and chemical applications

    CERN Document Server

    Becker, Edwin D

    1999-01-01

    High Resolution NMR provides a broad treatment of the principles and theory of nuclear magnetic resonance (NMR) as it is used in the chemical sciences. It is written at an "intermediate" level, with mathematics used to augment, rather than replace, clear verbal descriptions of the phenomena. The book is intended to allow a graduate student, advanced undergraduate, or researcher to understand NMR at a fundamental level, and to see illustrations of the applications of NMR to the determination of the structure of small organic molecules and macromolecules, including proteins. Emphasis is on the study of NMR in liquids, but the treatment also includes high resolution NMR in the solid state and the principles of NMR imaging and localized spectroscopy. Careful attention is given to developing and interrelating four approaches - steady state energy levels, the rotating vector picture, the density matrix, and the product operator formalism. The presentation is based on the assumption that the reader has an acquaintan...

  3. PVT Degradation Studies: NMR Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Herman M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kouzes, Richard T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2017-06-06

    Under certain environmental conditions, polyvinyl toluene (PVT) plastic scintillator has been observed to undergo internal fogging. Nuclear magnetic resonance spectroscopy has been used to elucidate the state of water inside the PVT. The deuterium NMR results show that water absorbed by PVT under warm, humid conditions enters several distinct environments, and when the PVT is transferred from incubation to ambient temperature and humidity the water is lost on a time scale of a few hours from these samples. Most of the deuterium NMR peaks can be assigned to bulk liquid water, but almost 35% of the detected signal intensity is contained in a resonance that resembles spectra of water contained in nanometer-scale pores in mesoporous carbon.

  4. NMR imaging of human atherosclerosis

    International Nuclear Information System (INIS)

    Toussaint, J.F.

    1995-01-01

    Diagnosis and prognosis of atherosclerosis can no longer be evaluated with morphological parameters only. A description of atherosclerotic plaque composition is necessary to study the mechanisms of plaque rupture, which depends on collagenous cap and lipid core thicknesses. NMR, as a biochemical imaging technique, allows visualization of these components using T1 contrast (mobile lipids), T2 contrast (cap vs. core), spin density (calcifications), diffusion imaging, 1H and 13C spectroscopy. Today, these imaging sequences allow to study in vitro the effects of interventional techniques such as angioplasty or atherectomy. Clinical investigations begin, which will attempt to develop in vivo microscopy and test the ability of NMR to predict plaque rupture. (author). 13 refs., 7 figs

  5. Influenza A (H3N2) Variant Virus

    Science.gov (United States)

    ... Swine Variant Pandemic Other Influenza A (H3N2) Variant Virus Language: English (US) Español Recommend on Facebook Tweet Share Compartir Influenza viruses that normally circulate in pigs are called “variant” ...

  6. Nitrous oxide reduction in nodules: denitrification or N2 fixation?

    International Nuclear Information System (INIS)

    Coyne, M.S.; Focht, D.D.

    1987-01-01

    Detached cowpea nodules that contained a nitrous oxide reductase-positive (Nor + ) rhizobium strain (8A55) and a nitrous oxide reductase-negative (Nor - ) rhizobium strain (32H1) were incubated with 1% 15 N 2 O (95 atom% 15 N) in the following three atmospheres: aerobic with C 2 H 2 (10%), aerobic without C 2 H 2 , and anaerobic (argon atmosphere) without C 2 H 2 . The greatest production of 15 N 2 occurred anaerobically with 8A55, yet very little was formed with 32H1. Although acetylene reduction activity was slightly higher with 32H1, about 10 times more 15 N 2 was produced aerobically by 8A55 than by 32H1 in the absence of acetylene. The major reductive pathway of N 2 O reduction by denitrifying rhizobium strain 8A55 is by nitrous oxide reductase rather than nitrogenase

  7. Arensky. Silhouettes (Suite N 2), Op. 23 / Jonathan Swain

    Index Scriptorium Estoniae

    Swain, Jonathan

    1991-01-01

    Uuest heliplaadist "Arensky. Silhouettes (Suite N 2), Op. 23. Scrjabin. Symphony N 3 in C minor, Op. 43 "Le divin poeme". Danish National Radio Symphony Orchestra. Neeme Järvi. Chandos cassette ABTD 1509; CD CHAN 8898 (66 minutes)

  8. Optimising biological N2 fixation by legumes in farming systems

    International Nuclear Information System (INIS)

    Hardarson, Gudni; Atkins, Craig

    2001-01-01

    Whether grown as pulses for grain, as green manure, as pastures or as the tree components of agro-forestry systems, the value of leguminous crops lies in their ability to fix atmospheric N 2 , so reducing the use of expensive fertiliser N and enhancing soil fertility. N 2 fixing legumes provide the basis for developing sustainable farming systems that incorporate integrated nutrient management. By exploiting the stable nitrogen isotope 15 N, it has been possible to reliably measure rates of N 2 fixation in a wide range of agro-ecological field situations involving many leguminous species. The accumulated data demonstrate that there is a wealth of genetic diversity among legumes and their Rhizobium symbionts which can be used to enhance N 2 fixation. Practical agronomic and microbiological means to maximise N inputs by legumes have also been identified. (author)

  9. The promotive effect of N 2 fixers, Bacillus circulans and ...

    African Journals Online (AJOL)

    The promotive effect of N 2 fixers, Bacillus circulans and Saccharomyces cerevisiae on the viability of native arbuscular mycorrhizal fungi and the impact on the productivity of alfalfa ( Medicago sativa l.)

  10. N2R vs. DR Network Infrastructure Evaluation

    DEFF Research Database (Denmark)

    Pedersen, Jens Myrup; Roost, Lars Jessen; Toft, Per Nesager

    2007-01-01

    Recent development of Internet-based services has set higher requirements to network infrastructures in terms of more bandwidth, lower delays and more reliability. Theoretical research within the area of Structural Quality of Service (SQoS) has introduced a new type of infrastructure which meet...... these requirements: N2R infrastructures. This paper contributes to the ongoing research with a case study from North Jutland. An evaluation of three N2R infrastructures compared to a Double Ring (DR) infrastructure will provide valuable information of the practical applicability of N2R infrastructures. In order...... to study if N2R infrastructures perform better than the DR infrastructure, a distribution network was established based on geographical information system (GIS) data. Nodes were placed with respect to demographic and geographical factors. The established distribution network was investigated with respect...

  11. The N=2 supersymmetric Ward-identities on harmonic superspace

    International Nuclear Information System (INIS)

    Lhallabi, T.

    1986-09-01

    The quantization of N=2 supersymmetric Yang-Mills theory coupled to matter hypermultiplet has been done in the harmonic superspace, by requiring BRS and anti-BRS invariance. Also the corresponding Ward-identities have been derived. (author)

  12. High resolution NMR in zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, Anix [INTEVEP, Filial de Petroleos de Venezuela, SA, Caracas (Venezuela). Dept. de Analisis y Evalucion

    1992-12-31

    In this work {sup 29} Si and {sup 27} Al NMR spectroscopy was used to study various types of zeolites. The corresponding spectra were used to measure the Si/Al ratios, to follow chemical modifications induced by acid and hydrothermal treatments, to determine non-equivalent crystallographic sites in highly dealuminated mordenites, and to detect modifications of faujasites due to the insertion of titanium atoms in the lattice. (author) 7 refs., 7 figs., 2 tabs.

  13. High resolution NMR in zeolites

    International Nuclear Information System (INIS)

    Diaz, Anix

    1991-01-01

    In this work 29 Si and 27 Al NMR spectroscopy was used to study various types of zeolites. The corresponding spectra were used to measure the Si/Al ratios, to follow chemical modifications induced by acid and hydrothermal treatments, to determine non-equivalent crystallographic sites in highly dealuminated mordenites, and to detect modifications of faujasites due to the insertion of titanium atoms in the lattice. (author)

  14. Singularity theory and N = 2 superconformal field theories

    International Nuclear Information System (INIS)

    Warner, N.P.

    1989-01-01

    The N = 2 superconformal field theories that appear at the fixed points of the renormalization group flows of Landau-Ginsburg models are discussed. Some of the techniques of singularity theory are employed to deduce properties of these superconformal theories. These ideas are then used to deduce the relationship between Calabi-Yau compactifications and tensored discrete series models. The chiral rings of general N = 2 superconformal theories are also described. 14 refs

  15. Alkali promotion of N-2 dissociation over Ru(0001)

    DEFF Research Database (Denmark)

    Mortensen, Jens Jørgen; Hammer, Bjørk; Nørskov, Jens Kehlet

    1998-01-01

    Using self-consistent density functional calculations, we show that adsorbed Na and Cs lower the barrier for dissociation of N2 on Ru(0001). Since N2 dissociation is a crucial step in the ammonia synthesis reaction, we explain in this way the experimental observation that alkali metals promote th...... the ammonia synthesis reaction over Ru catalysts. We also show that the origin of this effect is predominantly a direct electrostatic attraction between the adsorbed alkali atoms and the dissociating molecule....

  16. Emission of N2O from production of energy crops

    International Nuclear Information System (INIS)

    Lind, A.M.; Joergensen, U.; Maag, M.

    1995-01-01

    The contribution of N 2 O (nitrous oxide) to the greenhouse effect has been increasing during the latest years. The increase in the contribution from N 2 O is partly caused by increasing emission from soil, mainly due to human activity, and partly as a result of an increasing radiatively greenhouse effect as relative to CO 2 according to general recalculations and reevaluation. The contribution from agriculture is directly from cultivated soil as well as indirectly (production of fertilizer and food). Formation of N 2 O in soil is mainly dependent on variations in content of soil water, oxygen state, and on availability of organic matter. Soil type and cropping are also important. The factors are interrelated, and their influence on the two N 2 O-forming processes, nitrification and denitrification, are very fluctuating resulting in large variations (spatial and temporal) for measurements of the emission in field. In the present paper, the state of knowledge is given for the emission of nitrous oxide from cultivated soil as well as from different types of natural ecosystems. Significant differences between N 2 O-emission from different annual crops cannot be expected. Based on Danish measurements of N 2 O-emission (spring barley, winter wheat and spring rape) the net displacement of CO 2 is calculated. The deduction of N 2 O varied from being double as high as the deduction for the production dependent CO 2 -emission to a lot less than that. There was a marked influence of the yields of the specific crops in the actual measuring years on the relative effect of the N 2 O deduction on the net-displacement of CO 2 . (EG)

  17. Advanced NMR technology for bioscience and biotechnology

    Energy Technology Data Exchange (ETDEWEB)

    Hammel, P.C.; Hernandez, G.; Trewhella, J.; Unkefer, C.J. [Los Alamos National Lab., NM (US); Boumenthal, D.K. [Univ. of Utah, Salt Lake City, UT (US); Kennedy, M.A. [Pacific Northwest National Lab., Richland, WA (US); Moore, G.J. [Wayne State Univ., Detroit, MI (US)

    1998-11-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). NMR plays critical roles in bioscience and biotechnology in both imaging and structure determination. NMR is limited, however, by the inherent low sensitivity of the NMR experiment and the demands for spectral resolution required to study biomolecules. The authors addressed both of these issues by working on the development of NMR force microscopy for molecular imaging, and high field NMR with isotope labeling to overcome limitations in the size of biomolecules that can be studied using NMR. A novel rf coil design for NMR force microscopy was developed that increases the limits of sensitivity in magnetic resonance detection for imaging, and the authors demonstrated sub-surface spatial imaging capabilities. The authors also made advances in the miniaturization of two critical NMR force microscope components. They completed high field NMR and isotope labeling studies of a muscle protein complex which is responsible for regulating muscle contraction and is too large for study using conventional NMR approaches.

  18. Solid-state NMR of inorganic semiconductors.

    Science.gov (United States)

    Yesinowski, James P

    2012-01-01

    Studies of inorganic semiconductors by solid-state NMR vary widely in terms of the nature of the samples investigated, the techniques employed to observe the NMR signal, and the types of information obtained. Compared with the NMR of diamagnetic non-semiconducting substances, important differences often result from the presence of electron or hole carriers that are the hallmark of semiconductors, and whose theoretical interpretation can be involved. This review aims to provide a broad perspective on the topic for the non-expert by providing: (1) a basic introduction to semiconductor physical concepts relevant to NMR, including common crystal structures and the various methods of making samples; (2) discussions of the NMR spin Hamiltonian, details of some of the NMR techniques and strategies used to make measurements and theoretically predict NMR parameters, and examples of how each of the terms in the Hamiltonian has provided useful information in bulk semiconductors; (3) a discussion of the additional considerations needed to interpret the NMR of nanoscale semiconductors, with selected examples. The area of semiconductor NMR is being revitalized by this interest in nanoscale semiconductors, the great improvements in NMR detection sensitivity and resolution that have occurred, and the current interest in optical pumping and spintronics-related studies. Promising directions for future research will be noted throughout.

  19. Oceanic N2O emissions in the 21st century

    Science.gov (United States)

    Martinez-Rey, J.; Bopp, L.; Gehlen, M.; Tagliabue, A.; Gruber, N.

    2014-12-01

    The ocean is a substantial source of nitrous oxide (N2O) to the atmosphere, but little is known on how this flux might change in the future. Here, we investigate the potential evolution of marine N2O emissions in the 21st century in response to anthropogenic climate change using the global ocean biogeochemical model NEMO-PISCES. We implemented two different parameterizations of N2O production, which differ primarily at low oxygen (O2) conditions. When forced with output from a climate model simulation run under the business-as-usual high CO2 concentration scenario (RCP8.5), our simulations suggest a decrease of 4 to 12% in N2O emissions from 2005 to 2100, i.e., a reduction from 4.03/3.71 to 3.54/3.56 Tg N yr-1 depending on the parameterization. The emissions decrease strongly in the western basins of the Pacific and Atlantic oceans, while they tend to increase above the Oxygen Minimum Zones (OMZs), i.e., in the Eastern Tropical Pacific and in the northern Indian Ocean. The reduction in N2O emissions is caused on the one hand by weakened nitrification as a consequence of reduced primary and export production, and on the other hand by stronger vertical stratification, which reduces the transport of N2O from the ocean interior to the ocean surface. The higher emissions over the OMZ are linked to an expansion of these zones under global warming, which leads to increased N2O production associated primarily with denitrification. From the perspective of a global climate system, the averaged feedback strength associated with the projected decrease in oceanic N2O emissions amounts to around -0.009 W m-2 K-1, which is comparable to the potential increase from terrestrial N2O sources. However, the assesment for a compensation between the terrestrial and marine feedbacks calls for an improved representation of N2O production terms in fully coupled next generation of Earth System Models.

  20. Infrared spectroscopy of physisorbed and chemisorbed N-2 in the Pt(111)(3x3)N-2 structure

    DEFF Research Database (Denmark)

    Gustafsson, K.; Karlberg, Gustav; Andersson, Sven

    2007-01-01

    Using infrared spectroscopy and low electron energy diffraction, we have investigated the adsorption of N-2, at 30 K, on the Pt(111) and the Pt(111)(1x1)H surfaces. At monolayer coverage, N-2 orders in commensurate (3x3) structures on both surfaces, and we propose that the unit cells contain four...... molecules in each case. The infrared spectra reveal that N-2 exclusively physisorbs on the Pt(111)(1x1)H surface, while both physisorbed and chemisorbed N-2 is detected on the Pt(111) surface. Physisorbed N-2 is the majority species in the latter case, and the two adsorption states show an almost identical...... uptake behavior, which indicates that they are intrinsic constituents of the growing (3x3) N-2 islands. An analysis of the infrared absorbance data, based on a simple scaling concept suggested by density functional theory calculations, supports a model in which the (3x3) unit cell contains one...

  1. The vibration-rotation-tunneling levels of N2-H2O and N2-D2O

    Science.gov (United States)

    Wang, Xiao-Gang; Carrington, Tucker

    2015-07-01

    In this paper, we report vibration-rotation-tunneling levels of the van der Waals clusters N2-H2O and N2-D2O computed from an ab initio potential energy surface. The only dynamical approximation is that the monomers are rigid. We use a symmetry adapted Lanczos algorithm and an uncoupled product basis set. The pattern of the cluster's levels is complicated by splittings caused by H-H exchange tunneling (larger splitting) and N-N exchange tunneling (smaller splitting). An interesting result that emerges from our calculation is that whereas in N2-H2O, the symmetric H-H tunnelling state is below the anti-symmetric H-H tunnelling state for both K = 0 and K = 1, the order is reversed in N2-D2O for K = 1. The only experimental splitting measurements are the D-D exchange tunneling splittings reported by Zhu et al. [J. Chem. Phys. 139, 214309 (2013)] for N2-D2O in the v2 = 1 region of D2O. Due to the inverted order of the split levels, they measure the sum of the K = 0 and K = 1 tunneling splittings, which is in excellent agreement with our calculated result. Other splittings we predict, in particular those of N2-H2O, may guide future experiments.

  2. Teaching NMR spectra analysis with nmr.cheminfo.org.

    Science.gov (United States)

    Patiny, Luc; Bolaños, Alejandro; Castillo, Andrés M; Bernal, Andrés; Wist, Julien

    2018-06-01

    Teaching spectra analysis and structure elucidation requires students to get trained on real problems. This involves solving exercises of increasing complexity and when necessary using computational tools. Although desktop software packages exist for this purpose, nmr.cheminfo.org platform offers students an online alternative. It provides a set of exercises and tools to help solving them. Only a small number of exercises are currently available, but contributors are invited to submit new ones and suggest new types of problems. Copyright © 2018 John Wiley & Sons, Ltd.

  3. Dynamic pulsed-field-gradient NMR

    CERN Document Server

    Sørland, Geir Humborstad

    2014-01-01

    Dealing with the basics, theory and applications of dynamic pulsed-field-gradient NMR NMR (PFG NMR), this book describes the essential theory behind diffusion in heterogeneous media that can be combined with NMR measurements to extract important information of the system being investigated. This information could be the surface to volume ratio, droplet size distribution in emulsions, brine profiles, fat content in food stuff, permeability/connectivity in porous materials and medical applications currently being developed. Besides theory and applications it will provide the readers with background knowledge on the experimental set-ups, and most important, deal with the pitfalls that are numerously present in work with PFG-NMR. How to analyze the NMR data and some important basic knowledge on the hardware will be explained, too.

  4. Isotopologue fractionation during N(2)O production by fungal denitrification.

    Science.gov (United States)

    Sutka, Robin L; Adams, Gerard C; Ostrom, Nathaniel E; Ostrom, Peggy H

    2008-12-01

    Identifying the importance of fungi to nitrous oxide (N2O) production requires a non-intrusive method for differentiating between fungal and bacterial N2O production such as natural abundance stable isotopes. We compare the isotopologue composition of N2O produced during nitrite reduction by the fungal denitrifiers Fusarium oxysporum and Cylindrocarpon tonkinense with published data for N2O production during bacterial nitrification and denitrification. The fractionation factors for bulk nitrogen isotope values for fungal denitrification were in the range -74.7 to -6.6 per thousand. There was an inverse relationship between the absolute value of the fractionation factors and the reaction rate constant. We interpret this in terms of variation in the relative importance of the rate constants for diffusion and enzymatic reduction in controlling the net isotope effect for N2O production during fungal denitrification. Over the course of nitrite reduction, the delta(18)O values for N2O remained constant and did not exhibit a relationship with the concentration characteristic of an isotope effect. This probably reflects isotopic exchange with water. Similar to the delta(18)O data, the site preference (SP; the difference in delta(15)N between the central and outer N atoms in N2O) was unrelated to concentration during nitrite reduction and, therefore, has the potential to act as a conservative tracer of production from fungal denitrification. The SP values of N2O produced by F. oxysporum and C. tonkinense were 37.1 +/- 2.5 per thousand and 36.9 +/- 2.8 per thousand, respectively. These SP values are similar to those obtained in pure culture studies of bacterial nitrification but quite distinct from SP values for bacterial denitrification. The large magnitude of the bulk nitrogen isotope fractionation and the delta(18)O values associated with fungal denitrification are distinct from bacterial production pathways; thus multiple isotopologue data holds much promise for

  5. N2-fixing red alder indirectly accelerates ecosystem nitrogen cycling

    Science.gov (United States)

    Perakis, Steven S.; Matkins, Joselin J.; Hibbs, David E.

    2012-01-01

    Symbiotic N2-fixing tree species can accelerate ecosystem N dynamics through decomposition via direct pathways by producing readily decomposed leaf litter and increasing N supply to decomposers, as well as via indirect pathways by increasing tissue and detrital N in non-fixing vegetation. To evaluate the relative importance of these pathways, we compared three-year decomposition and N dynamics of N2-fixing red alder leaf litter (2.34 %N) to both low-N (0.68 %N) and high-N (1.21 %N) litter of non-fixing Douglas-fir, and decomposed each litter source in four forests dominated by either red alder or Douglas-fir. We also used experimental N fertilization of decomposition plots to assess elevated N availability as a potential mechanism of N2-fixer effects on litter mass loss and N dynamics. Direct effects of N2-fixing red alder on decomposition occurred primarily as faster N release from red alder than Douglas-fir litter, but direct increases in N supply to decomposers via fertilization did not stimulate decomposition of any litter. Fixed N indirectly influenced detrital dynamics by increasing Douglas-fir tissue and litter N concentrations, which accelerated litter N release without accelerating mass loss. By increasing soil N, tissue N, and the rate of N release from litter of non-fixers, we conclude that N2-fixing vegetation can indirectly foster plant-soil feedbacks that contribute to the persistence of elevated N availability in terrestrial ecosystems.

  6. An Inversion Recovery NMR Kinetics Experiment

    OpenAIRE

    Williams, Travis J.; Kershaw, Allan D.; Li, Vincent; Wu, Xinping

    2011-01-01

    A convenient laboratory experiment is described in which NMR magnetization transfer by inversion recovery is used to measure the kinetics and thermochemistry of amide bond rotation. The experiment utilizes Varian spectrometers with the VNMRJ 2.3 software, but can be easily adapted to any NMR platform. The procedures and sample data sets in this article will enable instructors to use inversion recovery as a laboratory activity in applied NMR classes and provide research students with a conveni...

  7. Investigation of nitrogen atom production in Ar/N2 and He/N2 surface wave plasmas

    International Nuclear Information System (INIS)

    Tabbal, M.; Kazopoulo, M.; Christidis, T.; Isber, S.

    2000-01-01

    Full text: There is presently great interest in nitrogen plasmas for surface coating processes. Such as the deposition of nitride thin films and surface treatment of materials. Indeed, nitrogen plasmas have been used to nitride the surface of ferrous and non-ferrous materials in order to improve their surface properties such as resistance to corrosion and hardness. Moreover, the design and development of nitrogen atom sources could be essential for the synthesis of gallium nitride (GaN), a wide band-gap semiconductor whose properties have revolutionized the microelectronics and optoelectronics industries. Correlations have been established between the density of active species in the process, namely atomic nitrogen (N) produced by the discharge and GaN film properties. Thus, it is of fundamental importance to investigate the N-atom production mechanisms in such discharges. N-atom production has been studied in pure N 2 surface-wave plasmas (SWP), as a function of operating parameters, namely gas pressure and electrical power. These studies indicate that the increase in the gas temperature (T g ) limits the N-atom production. One possible way of enhancing the N 2 dissociation rate ([N]/[N 2 ]) in the plasma could be the use of gas mixtures such as Ar/N 2 or He/N 2 . the aim of this paper is to characterize an Ar/N 2 and He/N 2 surface-wave discharge (SWD) by optical emission spectroscopy (OES), in order to determine the optimal plasma conditions in terms of [N]/[N 2 ]. The plasma is generated by a radio frequency (40.68 MHz) wave launcher. The effect of mixing N 2 with Ar and He on the production of N-atoms in the plasma was investigated at varying experimental conditions, such as operating pressure (4.5 and 7.5 Torr), electrical power (40 to 120 W), at a total gas flow of 250 sccm. It was found that [N]/[N 2 ] increases with the partial pressure of Ar in the mixture by a factor of about 8 at 120W. Such an enhancement is reduced at lower incident powers. On the

  8. NMR in structure-based drug design.

    Science.gov (United States)

    Carneiro, Marta G; Ab, Eiso; Theisgen, Stephan; Siegal, Gregg

    2017-11-08

    NMR spectroscopy is a powerful technique that can provide valuable structural information for drug discovery endeavors. Here, we discuss the strengths (and limitations) of NMR applications to structure-based drug discovery, highlighting the different levels of resolution and throughput obtainable. Additionally, the emerging field of paramagnetic NMR in drug discovery and recent developments in approaches to speed up and automate protein-observed NMR data collection and analysis are discussed. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  9. NMR spectroscopy using liquid crystal solvents

    CERN Document Server

    Emsley, JW

    2013-01-01

    NMR Spectroscopy using Liquid Crystal Solvents covers the importance of using a liquid crystal solvent in NMR to derive nuclear dipolar spin-spin coupling constants. This book is composed of ten chapters, and begins with a brief description of the features and benefits of liquid crystal in NMR spectroscopic analysis. The succeeding chapters deal with the mode of operation of nuclear spin Hamiltonian for partially oriented molecules and the analysis of NMR spectra of partially oriented molecules, as well as the determination of rigid molecule structure. These topics are followed by discussions

  10. Solution NMR structure determination of proteins revisited

    International Nuclear Information System (INIS)

    Billeter, Martin; Wagner, Gerhard; Wuethrich, Kurt

    2008-01-01

    This 'Perspective' bears on the present state of protein structure determination by NMR in solution. The focus is on a comparison of the infrastructure available for NMR structure determination when compared to protein crystal structure determination by X-ray diffraction. The main conclusion emerges that the unique potential of NMR to generate high resolution data also on dynamics, interactions and conformational equilibria has contributed to a lack of standard procedures for structure determination which would be readily amenable to improved efficiency by automation. To spark renewed discussion on the topic of NMR structure determination of proteins, procedural steps with high potential for improvement are identified

  11. NMR studies of isotopically labeled RNA

    Energy Technology Data Exchange (ETDEWEB)

    Pardi, A. [Univ. of Colorado, Boulder, CO (United States)

    1994-12-01

    In summary, the ability to generate NMR quantities of {sup 15}N and {sup 13}C-labeled RNAs has led to the development of heteronuclear multi-dimensional NMR techniques for simplifying the resonance assignment and structure determination of RNAs. These methods for synthesizing isotopically labeled RNAs are only several years old, and thus there are still relatively few applications of heteronuclear multi-dimensional NMR techniques to RNA. However, given the critical role that RNAs play in cellular function, one can expect to see an increasing number of NMR structural studies of biologically active RNAs.

  12. Ligand-receptor Interactions by NMR Spectroscopy

    Directory of Open Access Journals (Sweden)

    Novak. P.

    2008-04-01

    Full Text Available Today NMR spectroscopy is a method of choice for elucidation of interactions between biomolecules and the potential ligands. Knowledge on these interactions is an essential prerequisite for the rational drug design. The most important contribution of NMR to drug design a few years ago was the 3D structure determination of proteins. Besides delivering the 3D structures of the free proteins as a raw material for the modeling studies on ligand binding, NMR can directly yield valuable experimental data on the biologically important protein-ligand complexes. In addition to X-ray diffraction, NMR spectroscopy can provide information on the internal protein dynamics ordynamics of intermolecular interactions. Changes in NMR parameters allow us to detect ("SAR by NMR" and quantitatively determine binding affinities (titration, diffusion NMR experiments, etc. of potential ligands. Also, it is possible to determine the binding site and conformations of ligands, receptors and receptor-ligand complexes with the help of NMR methods such as tr-NOESY. Epitopes or functional groups responsible for binding of ligands to the receptor can be identified by employing STD or WaterLOGSY experiments. In this review are described some of the most frequent NMR methods for the characterization of the interactions between biomolecules and ligands, together with their advantages and disadvantages.

  13. Biologically fixed N2 as a source for N2O production in a grass–clover mixture, measured by 15N2 (erratum i vol. 74 p. 203)

    DEFF Research Database (Denmark)

    Carter, Mette Sustmann; Ambus, P.

    2006-01-01

    The contribution of biologically fixed dinitrogen (N-2) to the nitrous oxide (N2O) production in grasslands is unknown. To assess the contribution of recently fixed N-2 as a source of N2O and the transfer of fixed N from clover to companion grass, mixtures of white clover and perennial ryegrass...

  14. Covariant currents in N=2 super-Liouville theory

    International Nuclear Information System (INIS)

    Gomis, J.; Suzuki, Hiroshi

    1993-01-01

    Based on a path-integral prescription for anomaly calculation, we analyze an effective theory of the two-dimensional N=2 supergravity, i.e. N=2 super-Liouville theory. We calculate the anomalies associated with the BRST supercurrent and the ghost-number supercurrent. From those expressions of anomalies, we construct covariant BRST and ghost-number supercurrents in the effective theory. We then show that the (super-)coordinate BRST current algebra forms a superfield extension of the topological conformal algebra for an arbitrary type of conformal matter or, in terms of the string theory, for an arbitrary number of space-time dimensions. This fact is in great contrast with N=0 and N=1 (super-)Liouville theory, where the topological algebra singles out a particular value of dimensions. Our observation suggests a topological nature of the two-dimensional N=2 supergravity as a quantum theory. (orig.)

  15. From N=2 strings to M-theory

    International Nuclear Information System (INIS)

    Ketov, S.V.

    1997-01-01

    Taking the N=2 strings as the starting point, we discuss the equivalent self-dual field theories and analyze their symmetry structure in 2 + 2 dimensions. Restoring the full 'Lorentz' invariance in the target space necessarily leads to an extension of the N=2 string theory to a theory of 2 + 2 dimensional supermembranes propagating in 2 + 10 dimensional target space. The supermembrane requires maximal conformal supersymmetry in 2 + 2 dimensions, in the way advocated by Siegel, and it leads to the self-dual N=4 super-Yang-Mills theory and the self-dual N=8 (gauged) supergravity in 2+2 dimensions. The N=2 strings now appear on equal footing with the other string models as particular limits of the M-theory. (orig.)

  16. Some features of SUSY breaking in N=2 supergravity

    International Nuclear Information System (INIS)

    Cecotti, S.; Giradello, L.; Porrati, M.

    1984-08-01

    We discuss some features of SUSY breaking in N=2 Supergravity. Firstly, we show that in a general N=2 Sugra model (constructed according to the tensor calculus) all stationary points of the potential, at Λ=0, are fully supersymmetric if the compensating multiplet is not gauged. Thus a viable super-Higgs effect in N=2 supergravity can occur only in the presence of a Fayet-Iliopoulos term. Then we present an explicit model with two scales of breaking in anti-de Sitter space. Moreover, the ratio of the two gravitino masses is sliding i.e. not determined by the classical potential. In the extreme situation one of the gravitino mass equals √-Λ/3, and thus we have partial super-Higgs (in AdS space). The cosmological constant may be arranged to an arbitrary small value while keeping the mass of the heavy gravitino constant. (author)

  17. Lepton mixing predictions from Δ(6n2) family symmetry

    International Nuclear Information System (INIS)

    King, Stephen F.; Neder, Thomas; Stuart, Alexander J.

    2013-01-01

    We obtain predictions of lepton mixing parameters for direct models based on Δ(6n 2 ) family symmetry groups for arbitrarily large n in which the full Klein symmetry is identified as a subgroup of the family symmetry. After reviewing and developing the group theory associated with Δ(6n 2 ), we find many new candidates for large n able to yield reactor angle predictions within 3σ of recent global fits. We show that such Δ(6n 2 ) models with Majorana neutrinos predict trimaximal mixing with reactor angle θ 13 fixed up to a discrete choice, an oscillation phase of either zero or π and the atmospheric angle sum rules θ 23 =45°∓θ 13 /√(2), respectively, which are consistent with recent global fits and will be tested in the near future

  18. Determinant formula for the topological N = 2 superconformal algebra

    International Nuclear Information System (INIS)

    Doerrzapf, Matthias; Gato-Rivera, Beatriz

    1999-01-01

    The Kac determinant for the topological N = 2 superconformal algebra is presented as well as a detailed analysis of the singular vectors detected by the roots of the determinants. In addition we identify the standard Verma modules containing 'no-label' singular vectors (which are not detected directly by the roots of the determinants). We show that in standard Verma modules there are (at least) four different types of submodules, regarding size and shape. We also review the chiral determinant formula, for chiral Verma modules, adding new insights. Finally we transfer the results obtained to the Verma modules and singular vectors of the Ramond N = 2 algebra, which have been very poorly studied so far. This work clarifies several misconceptions and confusing claims appeared in the literature about the singular vectors, Verma modules and submodules of the topological N = 2 superconformal algebra

  19. Complex superspaces and prepotentials for N = 2 supergravity

    International Nuclear Information System (INIS)

    Sokatchev, E.

    1981-01-01

    A prepotential formulation of N=2 supergravity is constructed as a generalization of the non-minimal N=1 case. The non-minimal and minimal prepotential formulations of N=1 supergravity are briefly reviewed, the non-minimal case is then generalized to from the basis of the N=2 theory. The action of the Lorentz structure group is extracted from the transformation law of the spinar derivatives. Vielbeins and connections are defined and expressed in terms of the prepotentials. In evaluation of the torsion components the normal gauge technique is applied. The possibility of using the invariant volume of the chiral superspaces as an action for the N=2 supergravity is considered. (author)

  20. NMR characterization of pituitary tumors

    International Nuclear Information System (INIS)

    Osbakken, M.; Gonzales, J.; Page, R.

    1984-01-01

    Twelve patients (5 male, 7 female, mean age 37.9 +- 20) with pituitary tumors were extensively evaluated with NMR imaging using a 1.5K gauss resistive magnet. Saturation recovery (SR), inversion recovery (IR) and spin echo (SE) pulse sequences were used for qualitative characterization of the lesions. T/sub 1/ calculations were also performed for brain and pituitary. Tumor histology and endocrine status were correlated with NMR data. All tumors were large with suprasellar extension (6 with prolactin secretion, 6 without). Pituitary T/sub 1/'s ranged from .2 to .64, the mean T/sub 1/ being longer than that of brain (Brain = .4 +- .04; Pit = .48 +- .14). 3 patients with histological evidence of homogeneous adenomas had long T/sub 1/'s (0.58 +- .05). 3 patients with evidence of recent or old hemorhage into the pituitary had much shorter T/sub 1/'s (0.29 +- .12). There was no relationship between prolactin secretion and T/sub 1/. Qualitative T/sub 1/ and T/sub 2/ information can be obtained by using a combination of SR, IR, and SE images. Using this method in the patients, homogeneous adenomas had similar T/sub 1/'s and longer T/sub 2/'s compared to the brain, while patients with bleeds had shorter T/sub 1/'s and T/sub 2/'s. Image T/sub 1/ characteristics correlated well with the calculated T/sub 1/ values. The range of T/sub 1/ (and potentially T/sub 2/) values which occur in apparently similar lesions are most likely due to anatomical and pathophysiological variations in these lesions. It may be ultimately possible to separate different types of pathological processes based on NMR image T/sub 1/ and T/sub 2/ characteristics after careful comparative studies of NMR and histological data are completed. The combination of calculated T/sub 1/ and T/sub 2/ with image T/sub 1/ and T/sub 2/ information may also be useful in further characterization of lesions

  1. Short recovery time NMR probe

    International Nuclear Information System (INIS)

    Ramia, M.E.; Martin, C.A.; Jeandrevin, S.

    2011-01-01

    A NMR probe for low frequency and short recovery time is presented in this work. The probe contains the tuning circuit, diode expanders and quarter wavelength networks to protect the receiver from both the amplifier noise and the coil ringing following the transmitter power pulse. It also possesses a coil damper which is activated by of non active components. The probe performance shows a recovery time of about of 15μs a sensitive Q factor reduction and an increase of the signal to noise ratio of about 68% during the reception at a work frequency of 2 MHz. (author)

  2. Slowdown of N2O emissions from China's croplands

    Science.gov (United States)

    Zhou, F.; Shang, Z.; Ciais, P.; Piao, S.; Tian, H.; Saikawa, E.; Zaehle, S.; Del Grosso, S. J.; Galloway, J. N.

    2016-12-01

    To feed the increasing population, China has experienced a rapid agricultural development over past decades, accompanied by increased fertilizer consumptions in croplands, but the magnitude, trend, and causes of the associated nitrous oxide (N2O) emissions has remain unclear. The primary sources of this uncertainty are conflicting estimates of fertilizer consumption and emission factors, the latter being uncertain because of very few regional representativeness of the Nrate-flux relationships in China. Here we re-estimate China's N2O emissions from croplands using three different methods: flux upscaling technique, process-based models and atmospheric inversion, and also analyze the corresponding drivers using an attribution approach. The three methods produce similar estimates of N2O emissions in the range of 0.67 ± 0.08 to 0.62± 0.11 Tg nitrogen per year, which is 29% larger than the estimates by the Emission Database for Global Atmospheric Research (EDGAR) that is adopted by Intergovernmental Panel on Climate Change (IPCC) as the emission baseline and twofold larger than the latest Chinese national report submitted to the United Nations Framework Convention on Climate Change, but the revised trend slows down after 2005. Fertilizer N application per area is the dominant factor driving the increase in N2O emissions across most cropping regions from 1990 to 2004, but climate-induced change of emission factors has also controlled N2O flux from 2005 onwards. Our findings suggest that, as precipitation would increase in North China but decline in the South in future, EF will increasingly control China's agri. soil emissions of N2O, unless offset by larger reductions of fertilizer consumptions.

  3. Joyo ATWS test analysis by Mimir-N2

    International Nuclear Information System (INIS)

    Yoshida, Akihiro

    2001-03-01

    The study on the passive safety test by using the Experimental Fast Reactor Joyo was performed to demonstrate the inherent safety of fast breeder reactors. An analysis code: Mimir-N2, which has been developed to analyze Joyo plant kinetics, was selected as a standard code for this study. In order to increase the reliability of the calculation, Mimir-N2 code was adjusted based on the data obtained through several plant characteristics tests carried out in Joyo. Throughout an operational data obtained in Joyo, it is supposed that the burn-up dependency observed on the power reactivity coefficient might be coming from the reactivity shift caused by a depression of a thermal expansion of fuel pellet. Based on the relationship between the measured power reactivity coefficient and the core averaged burn-up, the burn-up dependency mentioned above was estimated and introduced to Mimir-N2. As a result, calculated core and plant dynamics during the step reactivity response test, such as the response of the power range neutron monitor and the coolant temperature at the core inlet/outlet, corresponded with the measured value. Especially, it was confirmed that Mimir-N2 can simulate the perturbation caused by the thermal expansion of the core support plate. In addition, Mimir-N2 was modified to be enable to take into account for the core bowing reactivity, which is calculated by the core bowing reactivity analysis system developed for Joyo. The preliminary analysis of the plant dynamics during the ATWS events in MK-III core were carried out by using modified Mimir-N2. As a result, it was confirmed that the core bowing reactivity should not be neglected because it sometimes shows positive feedback characteristics. (author)

  4. Performance of the WeNMR CS-Rosetta3 web server in CASD-NMR

    NARCIS (Netherlands)

    Van Der Schot, Gijs; Bonvin, Alexandre M J J

    We present here the performance of the WeNMR CS-Rosetta3 web server in CASD-NMR, the critical assessment of automated structure determination by NMR. The CS-Rosetta server uses only chemical shifts for structure prediction, in combination, when available, with a post-scoring procedure based on

  5. Experimental ion mobility measurements in Ne-N2

    International Nuclear Information System (INIS)

    Cortez, A.F.V.; Encarnação, P.M.C.C.; Santos, F.P.; Borges, F.I.G.M.; Conde, C.A.N.; Veenhof, R.; Neves, P.N.B.

    2016-01-01

    Data on ion mobility is important to improve the performance of large volume gaseous detectors, such as the ALICE TPC or in the NEXT experiment. In the present work the method, experimental setup and results for the ion mobility measurements in Ne-N 2 mixtures are presented. The results for this mixture show the presence of two peaks for different gas ratios of Ne-N 2 , low reduced electric fields, E / N , 10–20 Td (2.4–4.8 kV·cm −1 ·bar −1 ), low pressures 6–8 Torr (8–10.6 mbar) and at room temperature.

  6. Thermal expansion of crystals of the N2 type

    International Nuclear Information System (INIS)

    Tolkachev, A.M.; Manzhelii, V.G.; Azarenkov, V.P.; Jezowski, A.; Kosobutskaya, E.A.

    1981-01-01

    Linear expansion coefficients of low temperature crystals with linear molecules and Pa3 lattice N 2 (2-21 K), CO(2-28 K), CO 2 (2-25 K), N 2 O(2-90 K) were measured. A version of the law of corresponding states to describe the translational component of the thermal expansion of the substances studied and other low temperature crystals with close-packed lattices is proposed. In the thermal properties of crystals consisting of molecules without inversion centre, we have found anomalies interpreted as the evidence of a partial dipole ordering. (orig.)

  7. A Specific N=2 Supersymmetric Quantum Mechanical Model: Supervariable Approach

    Directory of Open Access Journals (Sweden)

    Aradhya Shukla

    2017-01-01

    Full Text Available By exploiting the supersymmetric invariant restrictions on the chiral and antichiral supervariables, we derive the off-shell nilpotent symmetry transformations for a specific (0 + 1-dimensional N=2 supersymmetric quantum mechanical model which is considered on a (1, 2-dimensional supermanifold (parametrized by a bosonic variable t and a pair of Grassmannian variables (θ,θ¯. We also provide the geometrical meaning to the symmetry transformations. Finally, we show that this specific N=2 SUSY quantum mechanical model is a model for Hodge theory.

  8. Duality and BPS spectra in N = 2 supersymmetric QCD

    International Nuclear Information System (INIS)

    Ferrari, F.

    1997-01-01

    I review, with some pedagogy, two different approaches to the computation of BPS spectra in N = 2 supersymmetric QCD with gauge group SU(2). The first one is semiclassical and has been widely used in the literature. The second one makes use of constraints coming from the non perturbative, global structure of the Coulomb branch of these theories. The second method allows for a description of discontinuities in the BPS spectra at strong coupling, and should lead to accurate test of duality conjectures in N = 2 theories. (orig.)

  9. Integrability and symmetry algebra associated with N=2 KP flows

    International Nuclear Information System (INIS)

    Ghosh, Sasanka; Sarma, Debojit

    2001-01-01

    We show the complete integrability of N=2 nonstandard KP flows establishing the bi-Hamiltonian structures. One of Hamiltonian structures is shown to be isomorphic to the nonlinear N=2 W ∞ algebra with the bosonic sector having W 1+∞ ·W ∞ structure. A consistent free field representation of the super conformal algebra is obtained. The bosonic generators are found to be an admixture of free fermions and free complex bosons, unlike the linear one. The fermionic generators become exponential in free fields, in general

  10. Synthesis of [1,3 - 15 N2] uracil

    International Nuclear Information System (INIS)

    Chiriac, M.; Axente, D.

    2001-01-01

    The synthesis of 15 N labelled uracil, using CO( 15 NH 2 ) 2 as starting material, is presented. The experimental procedure is an adaptation of the synthesis methods for the corresponding unlabelled compounds. Urea- 15 N 2 used as starting material was obtained from H 15 NO 3 (99 at.% 15 N) produced at National Institute for Research and Development of Isotopic and Molecular Technologies, Cluj-Napoca.The uracil structure was determined using the mass spectrometry method and the isotopic labelling was determined by the same method on the molecular compound. The synthesis scheme of (1,3- 15 N 2 ) uracil is presented. (authors)

  11. Duality and BPS spectra in N = 2 supersymmetric QCD

    Energy Technology Data Exchange (ETDEWEB)

    Ferrari, F. [Ecole Normale Superieure, 75 - Paris (France). Lab. de Physique Theorique

    1997-05-01

    I review, with some pedagogy, two different approaches to the computation of BPS spectra in N = 2 supersymmetric QCD with gauge group SU(2). The first one is semiclassical and has been widely used in the literature. The second one makes use of constraints coming from the non perturbative, global structure of the Coulomb branch of these theories. The second method allows for a description of discontinuities in the BPS spectra at strong coupling, and should lead to accurate test of duality conjectures in N = 2 theories. (orig.).

  12. Market Analysis DeN2O. Market potential for reduction of N2O emissions at nitric acid facilities

    International Nuclear Information System (INIS)

    Smit, A.W.; Gent, M.M.C.; Van den Brink, R.W.

    2001-05-01

    ECN has developed a technique for the removal of nitrous oxide (N2O) from the tail gases of a nitric acid plant. The aim of this project was to make an assessment of the market opportunities of this technique. To this end a study was made of the relevant international regulations and agreements on the field of climate policy. The formulation of an international greenhouse gas policy and concomitant flexible mechanisms is a prerequisite for the market introduction of any N2O abatement technique. The available techniques and techniques in development for N2O abatement in the nitric acid industry are described and the strengths and weaknesses are given. Furthermore, the costs per ton CO2 equivalents removed are estimated. Direct decomposition of N2O (either in the NH3 combustion reactor or downstream the absorber) are the most cost efficient techniques. Finally, the number and sizes of nitric acid plants in Europe and the developments in the fertiliser market are described. The current difficult fertiliser market makes the nitric acid producers reluctant to invest in N2O abatement technologies

  13. 1H-NMR urinalysis

    International Nuclear Information System (INIS)

    Yamamoto, Hideaki; Yamaguchi, Shuichi

    1988-01-01

    In an effort to examine the usefulness of 1 H-nuclear magnetic resonance (NMR) urinalysis in the diagnosis of congenital metabolic disorders, 70 kinds of urinary metabolites were analysed in relation to the diagnosis of inborn errors of amino acid and organic acid disorders. Homogated decoupling (HMG) method failed to analyze six metabolites within the undetectable range. When non-decoupling method (NON), in which the materials are dissolved in dimethyl sulfoxide, was used, the identification of signals became possible. The combination of HMG and NON methods was, therefore, considered to identify all of the metabolites. When the urine samples, which were obtained from patients with hyperglycerolemia, hyperornithinemia, glutaric acidemia type II, or glycerol kinase deficiency, were analysed by using both HMG and NON methods, abnormally increased urinary metabolites were detected. 1 H-NMR urinalysis, if used in the combination of HMG and NON methods, may allow simultanenous screening of inborn errors of metabolism of amino acid and organic acid disorders. (Namekawa, K.)

  14. Oxide, interface, and border traps in thermal, N2O, and N2O-nitrided oxides

    International Nuclear Information System (INIS)

    Fleetwood, D.M.; Saks, N.S.

    1996-01-01

    We have combined thermally stimulated-current (TSC) and capacitance endash voltage (C endash V) measurements to estimate oxide, interface, and effective border trap densities in 6 endash 23 nm thermal, N 2 O, and N 2 O-nitrided oxides exposed to ionizing radiation or high-field electron injection. Defect densities depend strongly on oxide processing, but radiation exposure and moderate high-field stress lead to similar trapped hole peak thermal energy distributions (between ∼1.7 and ∼2.0 eV) for all processes. This suggests that similar defects dominate the oxide charge trapping properties in these devices. Radiation-induced hole and interface trap generation efficiencies (0.1%endash 1%) in the best N 2 O and N 2 O-nitrided oxides are comparable to the best radiation hardened oxides in the literature. After ∼10 Mrad(SiO 2 ) x-ray irradiation or ∼10 mC/cm 2 constant current Fowler endash Nordheim injection, effective border trap densities as high as ∼5x10 11 cm -2 are inferred from C endash V hysteresis. These measurements suggest irradiation and high-field stress cause similar border trap energy distributions. In each case, even higher densities of compensating trapped electrons in the oxides (up to 2x10 12 cm -2 ) are inferred from combined TSC and C endash V measurements. These trapped electrons prevent conventional C endash V methods from providing accurate estimates of the total oxide trap charge density in many irradiation or high-field stress studies. Fewer compensating electrons per trapped hole (∼26%±5%) are found for irradiation of N 2 O and N 2 O-nitrided oxides than for thermal oxides (∼46%±7%). (Abstract Truncated)

  15. d = 2, N = 2 superconformal symmetries and models

    International Nuclear Information System (INIS)

    Delduc, F.; Gieres, F.; Gourmelen, S.

    1996-01-01

    We discuss the following aspects of two-dimensional N = 2 supersymmetric theories defined on compact super Riemann surfaces: parametrization of (2,0) and (2,2) superconformal structures in terms of Beltrami coefficients and formulation of superconformal models on such surfaces (invariant actions, anomalies and compensating actions, Ward identities). (author)

  16. Grassmann expansion of the classical N=2 supergravity field equations

    International Nuclear Information System (INIS)

    Embacher, F.

    1984-01-01

    The classical field equations of N=2 supergravity are expanded with respect to an infinite dimensional Grassmann algebra. The general freedom in constructing classical solution is exhibited. As an application, a uniqueness theorem for supersymmetric extreme black holes is given. (Author)

  17. Brazilian N2 laser similar to imported models

    International Nuclear Information System (INIS)

    Santos, P.A.M. dos; Tavares Junior, A.D.; Silva Reis, H. da; Tagliaferri, A.A.; Massone, C.A.

    1981-09-01

    The development of a high power N 2 Laser, similar to imported models but built enterely with Brazilian materials is described. The prototype shows pulse repetitivity that varies from 1 to 50 per second and has a peak power of 500 kW. (Author) [pt

  18. N 2 O Emissions and Inorganic N Release Following Incorporation ...

    African Journals Online (AJOL)

    West African Journal of Applied Ecology ... The results from the study demonstrated that whilst there is the potential for N2O emission to be controlled through varying ratios of residue:fertiliser input, the magnitude and direction of interactions between these N sources vary between different species as a result of their ...

  19. Near thermal charge transfer between Ar+2 and N2

    International Nuclear Information System (INIS)

    Holzscheiter, H.M.; Church, D.A.

    1981-01-01

    The near thermal charge transfer reaction of Ar +2 with N 2 has been studied at total pressures below 10 -7 Torr using a stored ion technique. Ar +2 ions produced by electron impact double ionization of Ar gas were selectively stored for times the order of seconds in a split-ring Penning-type ion trap. The decay with time of the initial ion sample number in a mixture of Ar and N 2 gases was fit to the sum of two exponentials, corresponding to different reaction rates for the 3 P and 1 D low-lying Ar +2 levels. The observed Ar +2 number decrease is attributed to the double-charge transfer process Ar +2 +N 2 →Ar+N 2 +2 →Ar+N + +N + in accord with recent flow-tube measurements. A rate constant for the metastable Ar +2 ( 1 D) level reaction with a value k( 1 D)=1.4 x 10 -9 cm 3 /sec is obtained, using the previously measured rate constant for the Ar +2 ( 3 P) state

  20. N2 vs H20 as purge/hydrostatic head

    International Nuclear Information System (INIS)

    Mast, J.C.

    1996-01-01

    This document provides the information to explain to the customer the ETP for the N2 vs H20 as Purge/Hydrostatic Head. This ETP follows the format described in Issurance of New Characterization Equipment Engineering Desk Instructions, 75200-95-013

  1. Superspace actions and duality transformations for N=2 tensor multiplets

    International Nuclear Information System (INIS)

    Galperin, A.; Ivanov, E.; Ogievetsky, V.

    1985-01-01

    General actions for self-interacting N=2 tensor multiplets are considered in the harmonic superspace approach. All of them are shown to be equivalent, by superfield duality transformations, to some restricted class of the hypermultiplets actions. In particular, the improved tensor multiplet theory is dual to a free hypermultiplet one. Superspace couplings of these improved matter multiplets against conformal supergravity are also constructed

  2. Off-shell N=2 linear multiplets in five dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Ozkan, Mehmet [Department of Physics, Istanbul Technical University,Maslak 34469 Istanbul (Turkey)

    2016-11-25

    We present a superconformal tensor calculus for an arbitrary number of five dimensional N=2 linear multiplets. We also demonstrate how to construct higher derivative invariants, and produce higher order supersymmetric off-diagonal models. Finally, we show the procedure required for the derivation of the supersymmetric completion of the non-Abelian F{sup 4} action.

  3. H9N2 avian influenza transmission and antigenicity

    Science.gov (United States)

    Low pathogenic H9N2 avian influenza has become endemic in parts of Asia, the Middle East and North Africa causing respiratory disease with occasional mortality. The use of vaccination has become common to try and control the clinical disease, but vaccination has not been shown to be an effective er...

  4. Dynamics of liquid N2 studied by neutron inelastic scattering

    DEFF Research Database (Denmark)

    Pedersen, Karen Schou; Carneiro, Kim; Hansen, Flemming Yssing

    1982-01-01

    Neutron inelastic-scattering data from liquid N2 at wave-vector transfer κ between 0.18 and 2.1 Å-1 and temperatures ranging from T=65-77 K are presented. The data are corrected for the contribution from multiple scattering and incoherent scattering. The resulting dynamic structure factor S (κ,ω)...

  5. Rimsky-Korsakov: Symphony N2 (Symphonic Suite) / Warrack, John

    Index Scriptorium Estoniae

    Warrack, John

    1990-01-01

    Uuest heliplaadist "Rimsky-Korsakov: Symphony N2 (Symphonic Suite), Op. 9, "Antar" Russian Easter Festival Overture, Op.36. Philharmonia Orchestra, Evgeni Svetlanov. Hyperion KA 66399. CDA 66399. Teise sümfoonia esitust võrreldud Neeme Järvi plaadistusega

  6. Weak coupling chambers in N=2 BPS quiver theory

    Energy Technology Data Exchange (ETDEWEB)

    Saidi, El Hassan, E-mail: h-saidi@fsr.ac.ma [Lab of High Energy Physics, Modeling and Simulations, Faculty of Science, University Mohammed V-Agdal, 4 Avenue Ibn Battota, Rabat (Morocco); Centre of Physics and Mathematics, CPM-CNESTEN, Rabat (Morocco)

    2012-11-01

    Using recent results on BPS quiver theory, we develop a group theoretical method to describe the quiver mutations encoding the quantum mechanical duality relating the spectra of distinct quivers. We illustrate the method by computing the BPS spectrum of the infinite weak chamber of some examples of N=2 supersymmetric gauge models without and with quark hypermultiplets.

  7. A 2PI/sub u/ state of N2+

    International Nuclear Information System (INIS)

    Wu, H.H.

    1975-01-01

    The N 2 + Meinel (N 2 + M) system (A 2 PI/sub u/ - X 2 Σ + /sub g/) was examined through steady state and transient electron excitation of pure N 2 in a semi-static system by 80-eV electrons in the pressure range from 0.5 mTorr to 50 mTorr, and at wave lengths in the 1800 to 9200 A region. Examination of the rotational structure of the (2,0) band indicates that the A state is inverted and that the rotational distribution is never in thermal equilibrium under any experimental condition in pure N 2 . The variation of electronic transition moment was estimated from the relative emission rates within the N 2 + M system, and can be described by a quadratic function of r-centroid, anti r, as R/sub e/(anti r)/R/sub e/(1.0) = 33.28 (1.0 - 1.8 anti r + 0.8 anti r 2 ), in the interval 1.02A less than anti r less than 1.14A. Two measurable decay components are detected in the transient observations. The shorter lived component with relative intensity greater than or equal to % of the total is believed to be from direct excitation-ionization. This component has a lifetime of 5.1 to +- 0.8 μsec, and a quenching coefficient of 7.9 x 10 -10 cm 3 /sec. The damping constant of the longer lived component is dominated by diffusion or drift loss and has an estimated zero pressure radiative probability of less than or equal to 0.05 μsec -1 . The quenching coefficient of the long lived component is estimated to be 3.7 x 10 -11 cm 3 /sec. Intersystem cascade among the high vibrational levels of the N 2 + X and N 2 + A state to explain the observed longer lived component. The variation is relative intensity of the two components in the 1 mTorr less than P less than 15 mTorr region can be described within experimental uncertainty by this model, with assumed1/tau = 0.06 μsec -1 and quenching coefficient of 1.2 x 10 -9 cm 3 sec -1 for the high vibrational levels of the A state

  8. Peptides containing internal residues of pyroglutamic acid: proton NMR characteristics

    International Nuclear Information System (INIS)

    Khan, S.A.

    1986-01-01

    The proton NMR characteristics of internal pyroglutamic acid (Glp; 5-oxoproline) residues in seven tripeptides of the general structure Boc-Xxx-Glp-Yyy-NH 2 were studied. In general, the chemical shifts of several diagnostic protons moved downfield on going from the Glu-containing peptides (Boc-Xxx-Glu-Yyy-NH 2 ) to the corresponding Glp-containing peptides. The C-2 proton of the Xxx residue was shifted by about 1.1 ppm. The N-2 proton of the Yyy residue was shifted by about 0.5 ppm. The C-2 proton of the Glx residue itself was shifted by about 0.5 ppm. One of the Glx C-3 protons was also shifted by about 0.5 ppm, but the other remained essentially unchanged. Finally, the Glx C-4 protons were shifted by about 0.3 ppm. Internal Glu residues are readily converted chemically into internal Glp residues. This conversion also occurs as a side reaction during HP cleavage of the protecting group from Glu(OBzl) residues. The spontaneous fragmentation of serum proteins C3, C4 and λ 2 -macroglobulin under denaturing conditions is probably due to regioselective hydrolysis of an internal Glp residue formed in each of these proteins upon denaturation. These proton NMR characteristics may be useful in establishing the presence of internal Glp residues in synthetic and natural peptides

  9. Powder-XRD and (14) N magic angle-spinning solid-state NMR spectroscopy of some metal nitrides.

    Science.gov (United States)

    Kempgens, Pierre; Britton, Jonathan

    2016-05-01

    Some metal nitrides (TiN, ZrN, InN, GaN, Ca3 N2 , Mg3 N2 , and Ge3 N4 ) have been studied by powder X-ray diffraction (XRD) and (14) N magic angle-spinning (MAS) solid-state NMR spectroscopy. For Ca3 N2 , Mg3 N2 , and Ge3 N4 , no (14) N NMR signal was observed. Low speed (νr  = 2 kHz for TiN, ZrN, and GaN; νr  = 1 kHz for InN) and 'high speed' (νr  = 15 kHz for TiN; νr  = 5 kHz for ZrN; νr  = 10 kHz for InN and GaN) MAS NMR experiments were performed. For TiN, ZrN, InN, and GaN, powder-XRD was used to identify the phases present in each sample. The number of peaks observed for each sample in their (14) N MAS solid-state NMR spectrum matches perfectly well with the number of nitrogen-containing phases identified by powder-XRD. The (14) N MAS solid-state NMR spectra are symmetric and dominated by the quadrupolar interaction. The envelopes of the spinning sidebands manifold are Lorentzian, and it is concluded that there is a distribution of the quadrupolar coupling constants Qcc 's arising from structural defects in the compounds studied. Copyright © 2015 John Wiley & Sons, Ltd.

  10. Early history of NMR at Los Alamos

    International Nuclear Information System (INIS)

    Jackson, J.A.

    1985-11-01

    Nuclear magnetic resonance (NMR) spectroscopy has developed into an important research tool in chemistry. More recently, NMR imaging and in vivo spectroscopy promise to produce a revolution in medicine and biochemistry. Early experiments at Los Alamos led to DOE programs involving stable isotopes of importance to biology and to medicine. These events are briefly recounted. 2 refs

  11. Characterization of natural bentonite by NMR

    International Nuclear Information System (INIS)

    Leite, Sidnei Q.M.; Dieguez, Lidia C.; Menezes, Sonia M.C.; San Gil, Rosane A.S.

    1993-01-01

    Solid state NMR as well as several other instrumental chemical analysis techniques were used in order to characterize two natural occurring bentonite. The methodology is described. The NMR spectra, together with the other used techniques suggest that the observed differences are due to iron inclusions in tetrahedral and octahedral sites

  12. Using Cloud Storage for NMR Data Distribution

    Science.gov (United States)

    Soulsby, David

    2012-01-01

    An approach using Google Groups as method for distributing student-acquired NMR data has been implemented. We describe how to configure NMR spectrometer software so that data is uploaded to a laboratory section specific Google Group, thereby removing bottlenecks associated with printing and processing at the spectrometer workstation. Outside of…

  13. Quartz Crystal Temperature Sensor for MAS NMR

    Science.gov (United States)

    Simon, Gerald

    1997-10-01

    Quartz crystal temperature sensors (QCTS) were tested for the first time as wireless thermometers in NMR MAS rotors utilizing the NMR RF technique itself for exiting and receiving electro-mechanical quartz resonances. This new tool in MAS NMR has a high sensitivity, linearity, and precision. When compared to the frequently used calibration of the variable temperature in the NMR system by a solid state NMR chemical shift thermometer (CST), such as lead nitrate, QCTS shows a number of advantages. It is an inert thermometer in close contact with solid samples operating parallel to the NMR experiment. QCTS can be manufactured for any frequency to be near a NMR frequency of interest (typically 1 to 2 MHz below or above). Due to the strong response of the crystal, signal detection is possible without changing the tuning of the MAS probe. The NMR signal is not influenced due to the relative sharp crystal resonance, restricted excitation by finite pulses, high probeQvalues, and commonly used audio filters. The quadratic dependence of the temperature increase on spinning speed is the same for the QCTS and for the CST lead nitrate and is discussed in terms of frictional heat in accordance with the literature about lead nitrate and with the results of a simple rotor speed jump experiment with differently radial located lead nitrate in the rotor.

  14. NMR studies of the structure of glasses

    International Nuclear Information System (INIS)

    Bray, P.J.; Gravina, S.J.; Stallworth, P.E.; Szu, S.P.; Jianhui Zhong

    1988-01-01

    Earlier continuous wave (CW) NMR studies of chemical bonding and structure in glasses are summarized. Examples are given of this use of the quadrupolar interaction and chemical shift to obtain structural information. New NMR data and analyses are presented for alkali borate and gallate glasses. Extensions to other elements (e.g. molybdenum, lanthanum) are suggested. 44 refs. (author)

  15. An Inversion Recovery NMR Kinetics Experiment

    Science.gov (United States)

    Williams, Travis J.; Kershaw, Allan D.; Li, Vincent; Wu, Xinping

    2011-01-01

    A convenient laboratory experiment is described in which NMR magnetization transfer by inversion recovery is used to measure the kinetics and thermochemistry of amide bond rotation. The experiment utilizes Varian spectrometers with the VNMRJ 2.3 software, but can be easily adapted to any NMR platform. The procedures and sample data sets in this…

  16. Selective sensitivity enhancement in FT-NMR

    International Nuclear Information System (INIS)

    Farrar, T.C.

    1987-01-01

    In this article the basic two-spin nuclear magnetic resonance (NMR) experiment and the new sensitivity enhancement experiments are reviewed. In part two of this two-part series an overview of two-dimensional NMR experiments will be presented. Part two will appear in the June 1 issue of Analytical Chemistry

  17. 2D NMR studies of biomolecules

    International Nuclear Information System (INIS)

    Lamerichs, R.M.J.N.

    1989-01-01

    The work described in this thesis comprises two related subjects. The first part describes methods to derive high-resolution structures of proteins in solution using two-dimensional (2-D) NMR. The second part describes 2-D NMR studies on the interaction between proteins and DNA. (author). 261 refs.; 52 figs.; 23 tabs

  18. Synthesis and NMR Elucidation of Novel Pentacycloundecane ...

    African Journals Online (AJOL)

    Herein we report the synthesis and NMR elucidation of five novel pentacycloundecane (PCU)-derived short peptides as potential HIV protease inhibitors. 1H and 13C spectral analysis show major overlapping of methine resonance of the PCU 'cage' thereby making it extremely difficult to assign the NMR signals. Attachment ...

  19. Development and applications of quantitative NMR spectroscopy

    International Nuclear Information System (INIS)

    Yamazaki, Taichi

    2016-01-01

    Recently, quantitative NMR spectroscopy has attracted attention as an analytical method which can easily secure traceability to SI unit system, and discussions about its accuracy and inaccuracy are also started. This paper focuses on the literatures on the advancement of quantitative NMR spectroscopy reported between 2009 and 2016, and introduces both NMR measurement conditions and actual analysis cases in quantitative NMR. The quantitative NMR spectroscopy using an internal reference method enables accurate quantitative analysis with a quick and versatile way in general, and it is possible to obtain the precision sufficiently applicable to the evaluation of pure substances and standard solutions. Since the external reference method can easily prevent contamination to samples and the collection of samples, there are many reported cases related to the quantitative analysis of biologically related samples and highly scarce natural products in which NMR spectra are complicated. In the precision of quantitative NMR spectroscopy, the internal reference method is superior. As the quantitative NMR spectroscopy widely spreads, discussions are also progressing on how to utilize this analytical method as the official methods in various countries around the world. In Japan, this method is listed in the Pharmacopoeia and Japanese Standard of Food Additives, and it is also used as the official method for purity evaluation. In the future, this method will be expected to spread as the general-purpose analysis method that can ensure traceability to SI unit system. (A.O.)

  20. NMR imaging of soft tissue tumors

    International Nuclear Information System (INIS)

    Laval-Jeantet, M.; Tobolsk, F.; Delepine, N.; Delepine, G.; Roger, B.; Cabanis, E.A.

    1986-01-01

    Preliminary findings on NMR imaging of 30 soft tissue tumors demonstrated the indispensable value of this examination (particularly when a surface antenna is used) for preoperative investigation and diagnosis of tumoral recurrence when compared with other radiologic techniques. The possible potential of NMR imaging for characterization of tissues, apart from lipoma or liposarcoma, cannot be evaluated at the present time [fr

  1. Solid polymer/salt electrolytes based on linear poly((N-2-cyanoethyl)ethylenimine)

    International Nuclear Information System (INIS)

    Erickson, M.; Frech, R.; Glatzhofer, D.T.

    2003-01-01

    There has been growing interest in the structure, properties, ionic association, and conductivity in poly(acrylonitrile) (PAN)/salt systems and its structural analogues. We have developed a simple procedure to cyanoethylate the nitrogen atoms (>95% by 1 H-NMR) of linear poly(ethylenimine) (PEI) to form poly((N-2-cyanoethyl)ethylenimine) (PCEEI). IR studies indicate that, like PAN, a second nitrile stretching band develops for PCEEI on addition of LiTf, indicating coordination of nitrile groups to Li cations. However, spectroscopic data on the triflate ions indirectly suggest that, unlike PAN/LiTf systems, PCEEI systems contain significant proportions of 'free' Li cations at high LiTf concentrations. Initial results indicate the RT ionic conductivity in the PCEEI systems is on the order of 10 -8 S cm -1 at a composition of N:Li=6:1 and was found to be largely independent of LiTf concentration over a range of sample concentrations. The nature of the relative concentrations of ionic species of LiTf in PCEEI was determined with infrared spectroscopy. Results of room temperature and variable temperature complex impedance measurements are presented

  2. Carbon-13 NMR spectroscopy of biological systems

    CERN Document Server

    Beckmann, Nicolau

    1995-01-01

    This book is intended to provide an in-depth understanding of 13C NMR as a tool in biological research. 13C NMR has provided unique information concerning complex biological systems, from proteins and nucleic acids to animals and humans. The subjects addressed include multidimensional heteronuclear techniques for structural studies of molecules in the liquid and solid states, the investigation of interactions in model membranes, the elucidation of metabolic pathwaysin vitro and in vivo on animals, and noninvasive metabolic studies performed on humans. The book is a unique mix of NMR methods and biological applications which makes it a convenient reference for those interested in research in this interdisciplinary area of physics, chemistry, biology, and medicine.Key Features* An interdisciplinary text with emphasis on both 13C NMR methodology and the relevant biological and biomedical issues* State-of-the-art 13C NMR techniques are described; Whenever possible, their advantages over other approaches are empha...

  3. Comparative pathology of pigs infected with Korean H1N1, H1N2, or H3N2 swine influenza A viruses

    OpenAIRE

    Lyoo, Kwang-Soo; Kim, Jeong-Ki; Jung, Kwonil; Kang, Bo-Kyu; Song, Daesub

    2014-01-01

    Background The predominant subtypes of swine influenza A virus (SIV) in Korea swine population are H1N1, H1N2, and H3N2. The viruses are genetically close to the classical U.S. H1N1 and triple-reassortant H1N2 and H3N2 viruses, respectively. Comparative pathogenesis caused by Korean H1N1, H1N2, and H3N2 SIV was evaluated in this study. Findings The H3N2 infected pigs had severe scores of gross and histopathological lesions at post-inoculation days (PID) 2, and this then progressively decrease...

  4. TransCom N2O model inter-comparison, Part II : Atmospheric inversion estimates of N2O emissions

    NARCIS (Netherlands)

    Thompson, R. L.; Ishijima, K.; Saikawa, E.; Corazza, M.; Karstens, U.; Patra, P. K.; Bergamaschi, P.; Chevallier, F.; Dlugokencky, E.; Prinn, R. G.; Weiss, R. F.; O'Doherty, S.; Fraser, P. J.; Steele, L. P.; Krummel, P. B.; Vermeulen, A.; Tohjima, Y.; Jordan, A.; Haszpra, L.; Steinbacher, M.; Van Der Laan, S.; Aalto, T.; Meinhardt, F.; Popa, Maria Elena; Moncrieff, J.; Bousquet, P.

    2014-01-01

    This study examines N2O emission estimates from 5 different atmospheric inversion frameworks. The 5 frameworks differ in the choice of atmospheric transport model, meteorological data, prior uncertainties and inversion method but use the same prior emissions and observation dataset. The mean

  5. TransCom N2O model inter-comparison - Part 2 : Atmospheric inversion estimates of N2O emissions

    NARCIS (Netherlands)

    Thompson, R. L.; Ishijima, K.; Saikawa, E.; Corazza, M.; Karstens, U.; Patra, P. K.; Bergamaschi, P.; Chevallier, F.; Dlugokencky, E.; Prinn, R. G.; Weiss, R. F.; O'Doherty, S.; Fraser, P. J.; Steele, L. P.; Krummel, P. B.; Vermeulen, A.; Tohjima, Y.; Jordan, A.; Haszpra, L.; Steinbacher, M.; Van Der Laan, S.; Aalto, T.; Meinhardt, F.; Popa, Maria Elena|info:eu-repo/dai/nl/375806407; Moncrieff, J.; Bousquet, P.

    2014-01-01

    This study examines N2O emission estimates from five different atmospheric inversion frameworks based on chemistry transport models (CTMs). The five frameworks differ in the choice of CTM, meteorological data, prior uncertainties and inversion method but use the same prior emissions and observation

  6. Quasicomplex N=2, d=1 Supersymmetric Sigma Models

    Directory of Open Access Journals (Sweden)

    Evgeny A. Ivanov

    2013-11-01

    Full Text Available We derive and discuss a new type of N=2 supersymmetric quantum mechanical sigma models which appear when the superfield action of the (1,2,1 multiplets is modified by adding an imaginary antisymmetric tensor to the target space metric, thus completing the latter to a non-symmetric Hermitian metric. These models are not equivalent to the standard de Rham sigma models, but are related to them through a certain special similarity transformation of the supercharges. On the other hand, they can be obtained by a Hamiltonian reduction from the complex supersymmetric N=2 sigma models built on the multiplets (2,2,0 and describing the Dolbeault complex on the manifolds with proper isometries. We study in detail the extremal two-dimensional case, when the target space metric is defined solely by the antisymmetric tensor, and show that the corresponding quantum systems reveal a hidden N=4 supersymmetry.

  7. An N=2 gauge theory and its supergravity dual

    CERN Document Server

    Brandhuber, A

    2000-01-01

    We study flows on the scalar manifold of N=8 gauged supergravity in five dimensions which are dual to certain mass deformations of N=4 super Yang-Mill theory. In particular, we consider a perturbation of the gauge theory by a mass term for the adjoint hyper-multiplet, giving rise to an N=2 theory. The exact solution of the 5-dim gauged supergravity equations of motion is found and the metric is uplifted to a ten-dimensional background of type-IIB supergravity. Using these geometric data and the AdS/CFT correspondence we analyze the spectra of certain operators as well as Wilson loops on the dual gauge theory side. The physical flows are parametrized by a single non-positive constant and describe part of the Coulomb branch of the N=2 theory at strong coupling.

  8. The N=2 super-W3 algebra

    International Nuclear Information System (INIS)

    Romans, L.J.

    1992-01-01

    We present the complete structure of the N=2 super-W 3 algebra, a non-linear extended conformal algebra containing the usual N=2 superconformal algebra (with generators of spins 1, 3/2, 3/2 and 2) and a higher-spin multiplet of generators with spins 2, 5/2, 5/2 and 3. We investigate various sub-algebras and related algebras, and find necessary conditions upon possible unitary representations of the algebra. In particular, the central charge c is restricted to two discrete series, one ascending and one descending to a common accumulation point c=6. The results suggest that the algebra is realised in certain (compact or non-compact) Kazama-Suzuki coset models, including a c=9 model proposed by Bars based on SU(2, 1)/U(2). (orig.)

  9. Superconformal invariance from N = 2 supersymmetry Ward identities

    International Nuclear Information System (INIS)

    Baulieu, Laurent; Bossard, Guillaume

    2008-01-01

    We algebraically prove the cancellation of the β function at all order of perturbation theory of N = 2 supersymmetric gauge theories with a vanishing one-loop β function. The proof generalises that recently given for the N = 4 case. It uses the consistent Slavnov-Taylor identities of the shadow dependent formulation. We also demonstrate the cancellation at all orders of the anomalous dimensions of vector and hypermultiplet 1/2 BPS operators

  10. R-symmetry violation in N=2 SUSY

    International Nuclear Information System (INIS)

    Volkov, G.G.; Maslikov, A.A.

    1990-01-01

    The present paper discusses the spontaneous R-symmetry violation in the N=2 SUSY SU(4)xU(1) model with soft SUSY breaking terms preserving finiteness. (In this case an invisible axion appears). In particular, the mechanism producting a light photino mass up to some GeV is suggested. In R-odd version of this model the mechanisms of enhancement of the neutrino decay is discussed. 10 refs.; 3 figs

  11. Experimental and theoretical studies on the structural, spectroscopic and hydrogen bonding on 4-nitro-n-(2,4-dinitrophenyl) benzenamine

    Science.gov (United States)

    Subhapriya, G.; Kalyanaraman, S.; Jeyachandran, M.; Ragavendran, V.; Krishnakumar, V.

    2018-04-01

    Synthesized 4-nitro-N-(2,4-dinitrophenyl) benzenamine (NDPBA) molecule was confirmed applying the tool of NMR. Theoretical prediction addressed the NMR chemical shifts and correlated well with the experimental data. The molecule subjected to theoretical DFT at 6-311++G** level unraveled the spectroscopic and structural properties of the NDPBA molecule. Moreover the structural features proved the occurrence of intramolecular Nsbnd H· · O hydrogen bonding in the molecule which was further confirmed with the help of Frontier molecular orbital analysis. Vibrational spectroscopic characterization through FT-IR and Raman experimentally and theoretically gave an account for the vibrational properties. An illustration of the topology of the molecule theoretically helped also in finding the hydrogen bonding energy.

  12. The Lie algebra of the N=2-string

    International Nuclear Information System (INIS)

    Kugel, K.

    2006-01-01

    The theory of generalized Kac-Moody algebras is a generalization of the theory of finite dimensional simple Lie algebras. The physical states of some compactified strings give realizations of generalized Kac-Moody algebras. For example the physical states of a bosonic string moving on a 26 dimensional torus form a generalized Kac-Moody algebra and the physical states of a N=1 string moving on a 10 dimensional torus form a generalized Kac-Moody superalgebra. A natural question is whether the physical states of the compactified N=2-string also realize such an algebra. In this thesis we construct the Lie algebra of the compactified N=2-string, study its properties and show that it is not a generalized Kac-Moody algebra. The Fock space of a N=2-string moving on a 4 dimensional torus can be described by a vertex algebra constructed from a rational lattice of signature (8,4). Here 6 coordinates with signature (4,2) come from the matter part and 6 coordinates with signature (4,2) come from the ghost part. The physical states are represented by the cohomology of the BRST-operator. The vertex algebra induces a product on the vector space of physical states that defines the structure of a Lie algebra on this space. This Lie algebra shares many properties with generalized Kac-Moody algebra but we will show that it is not a generalized Kac-Moody algebra. (orig.)

  13. 4d N=2 theories with disconnected gauge groups

    Energy Technology Data Exchange (ETDEWEB)

    Argyres, Philip C.; Martone, Mario [Physics Department, University of Cincinnati,PO Box 210011, Cincinnati OH 45221 (United States)

    2017-03-28

    In this paper we present a beautifully consistent web of evidence for the existence of interacting 4d rank-1 N=2 SCFTs obtained from gauging discrete subgroups of global symmetries of other existing 4d rank-1 N=2 SCFTs. The global symmetries that can be gauged involve a non-trivial combination of discrete subgroups of the U(1){sub R}, low-energy EM duality group SL(2,ℤ), and the outer automorphism group of the flavor symmetry algebra, Out(F). The theories that we construct are remarkable in many ways: (i) two of them have exceptional F{sub 4} and G{sub 2} flavor groups; (ii) they substantially complete the picture of the landscape of rank-1 N=2 SCFTs as they realize all but one of the remaining consistent rank-1 Seiberg-Witten geometries that we previously constructed but were not associated to known SCFTs; and (iii) some of them have enlarged N=3 SUSY, and have not been previously constructed. They are also examples of SCFTs which violate the Shapere-Tachikawa relation between the conformal central charges and the scaling dimension of the Coulomb branch vev. We propose a modification of the formulas computing these central charges from the topologically twisted Coulomb branch partition function which correctly compute them for discretely gauged theories.

  14. N=2 vacua in electrically gauged N=4 supergravities

    Energy Technology Data Exchange (ETDEWEB)

    Horst, Christoph

    2013-06-15

    In this thesis we study N= 2 vacua in gauged N=4 supergravity theories in fourdimensional spacetime. Using the embedding tensor formalism that describes general consistent magnetic gaugings of an ungauged N=4 matter-coupled supergravity theory in a symplectic frame with SO(1,1) x SO(6,n) off-shell symmetry we formulate necessary conditions for partial supersymmetry breaking and find that the Killing spinor equations can be solved for the embedding tensor components. Subsequently, we show that the classification of theories that allow for vacua with partial supersymmetry amounts to solving a system of purely algebraic quadratic equations. Then, we restrict ourselves to the class of purely electric gaugings and explicitly construct a class of consistent super-Higgs mechanisms and study its properties. In particular, we find that the spectrum fills complete N=2 supermultiplets that are either massless or BPS. Furthermore, we demonstrate that (modulo an abelian Lie algebra) arbitrary unbroken gauge Lie algebras can be realized provided that the number of N=4 vector multiplets is sufficiently large. Finally, we compute the relevant terms of the effective action below the scale of partial supersymmetry breaking and argue that the special Kaehler manifold for the scalars of the N=2 vector multiplets has to be in the unique series of special Kaehler product manifolds.

  15. The Lie algebra of the N=2-string

    Energy Technology Data Exchange (ETDEWEB)

    Kugel, K

    2006-07-01

    The theory of generalized Kac-Moody algebras is a generalization of the theory of finite dimensional simple Lie algebras. The physical states of some compactified strings give realizations of generalized Kac-Moody algebras. For example the physical states of a bosonic string moving on a 26 dimensional torus form a generalized Kac-Moody algebra and the physical states of a N=1 string moving on a 10 dimensional torus form a generalized Kac-Moody superalgebra. A natural question is whether the physical states of the compactified N=2-string also realize such an algebra. In this thesis we construct the Lie algebra of the compactified N=2-string, study its properties and show that it is not a generalized Kac-Moody algebra. The Fock space of a N=2-string moving on a 4 dimensional torus can be described by a vertex algebra constructed from a rational lattice of signature (8,4). Here 6 coordinates with signature (4,2) come from the matter part and 6 coordinates with signature (4,2) come from the ghost part. The physical states are represented by the cohomology of the BRST-operator. The vertex algebra induces a product on the vector space of physical states that defines the structure of a Lie algebra on this space. This Lie algebra shares many properties with generalized Kac-Moody algebra but we will show that it is not a generalized Kac-Moody algebra. (orig.)

  16. Magnetism and structural chemistry of the n=2 Ruddlesden-Popper phase La3LiMnO7

    International Nuclear Information System (INIS)

    Battle, Peter D.; Burley, Jonathan C.; Gallon, Daniel J.; Grey, Clare P.; Sloan, Jeremy

    2004-01-01

    Polycrystalline samples of the n=2 Ruddlesden-Popper phase La 3 LiMnO 7 have been prepared and characterized. X-ray and neutron diffraction suggest that the structure is tetragonal with a disordered distribution of Li and Mn cations over the octahedral sites, but 6 Li MAS NMR shows that the Li and Mn are 1:1 ordered locally. Electron microscopy shows that the stacking of the cation-ordered, perovskite-like bilayers along the crystallographic z-axis is disordered on the distance scale sampled by X-ray and neutron diffraction. Magnetometry data and neutron diffraction data collected at 2 K together suggest that the Mn cations within each structural domain order antiferromagnetically at 14 K, but that the disorder along z prevents the establishment of long-range magnetic order

  17. An introduction to biological NMR spectroscopy

    International Nuclear Information System (INIS)

    Marion, Dominique

    2013-01-01

    NMR spectroscopy is a powerful tool for biologists interested in the structure, dynamics, and interactions of biological macromolecules. This review aims at presenting in an accessible manner the requirements and limitations of this technique. As an introduction, the history of NMR will highlight how the method evolved from physics to chemistry and finally to biology over several decades. We then introduce the NMR spectral parameters used in structural biology, namely the chemical shift, the J-coupling, nuclear Overhauser effects, and residual dipolar couplings. Resonance assignment, the required step for any further NMR study, bears a resemblance to jigsaw puzzle strategy. The NMR spectral parameters are then converted into angle and distances and used as input using restrained molecular dynamics to compute a bundle of structures. When interpreting a NMR-derived structure, the biologist has to judge its quality on the basis of the statistics provided. When the 3D structure is a priori known by other means, the molecular interaction with a partner can be mapped by NMR: information on the binding interface as well as on kinetic and thermodynamic constants can be gathered. NMR is suitable to monitor, over a wide range of frequencies, protein fluctuations that play a crucial role in their biological function. In the last section of this review, intrinsically disordered proteins, which have escaped the attention of classical structural biology, are discussed in the perspective of NMR, one of the rare available techniques able to describe structural ensembles. This Tutorial is part of the International Proteomics Tutorial Programme (IPTP 16 MCP). (authors)

  18. NMR imaging of the brain: initial impressions

    International Nuclear Information System (INIS)

    Spencer, D.H.; Bydder, G.M.

    1983-01-01

    An NMR imaging system designed and built by Thorn-EMI Ltd was installed at Hammersmith Hospital in March 1981. In the first year of operation 180 patients and 40 volunteers have had cranial examinations and initial impressions bases on this experience are presented. Patients with a wide variety of neurological diseases have been studied to provide a basis for diagnostic interpretation, to define distinctive features, and to evaluate different types of scanning sequences. NMR imaging appears to be of considerable value in neurological diagnosis and has a number of advantages over CT. The detailed evaluation of NMR imaging will require much more work but the initial results are very promising

  19. Oriented solid-state NMR spectrosocpy

    DEFF Research Database (Denmark)

    Bertelsen, Kresten

    This thesis is concerned with driving forward oriented solid-state NMR spectroscopy as a viable technique for studying peptides in membrane bilayers. I will show that structural heterogeneity is an intrinsic part of the peptide/lipid system and that NMR can be used to characterize static...... and dynamic structural features of the peptides and its local surroundings. In fact one need to take into account the dynamical features of the system in order to correctly predict the structure from oriented solid-state NMR spectra.      ...

  20. NMR reaction monitoring in flow synthesis

    Directory of Open Access Journals (Sweden)

    M. Victoria Gomez

    2017-02-01

    Full Text Available Recent advances in the use of flow chemistry with in-line and on-line analysis by NMR are presented. The use of macro- and microreactors, coupled with standard and custom made NMR probes involving microcoils, incorporated into high resolution and benchtop NMR instruments is reviewed. Some recent selected applications have been collected, including synthetic applications, the determination of the kinetic and thermodynamic parameters and reaction optimization, even in single experiments and on the μL scale. Finally, software that allows automatic reaction monitoring and optimization is discussed.

  1. NMR reaction monitoring in flow synthesis.

    Science.gov (United States)

    Gomez, M Victoria; de la Hoz, Antonio

    2017-01-01

    Recent advances in the use of flow chemistry with in-line and on-line analysis by NMR are presented. The use of macro- and microreactors, coupled with standard and custom made NMR probes involving microcoils, incorporated into high resolution and benchtop NMR instruments is reviewed. Some recent selected applications have been collected, including synthetic applications, the determination of the kinetic and thermodynamic parameters and reaction optimization, even in single experiments and on the μL scale. Finally, software that allows automatic reaction monitoring and optimization is discussed.

  2. Introduction to some basic aspects of NMR

    International Nuclear Information System (INIS)

    Goldman, M.

    1992-01-01

    The principal interactions are reviewed that are experienced by nuclear spins making magnetic resonance feasible and which disturb it in a way that gives access to the properties of bulk matter. The interactions leading to NMR include Zeeman interaction, dipole-dipole interactions, and exchange interactions. Spin-lattice relaxation relevant to NMR is revisited next. It is followed by an overview of spin temperature. Finally, the care of periodic Hamiltonian is discussed in detail as another contribution to NMR. (R.P.) 48 refs., 12 figs

  3. NMR study of LaPb2

    International Nuclear Information System (INIS)

    Ueda, K.; Kohara, T.; Yamada, Y.

    1995-01-01

    La and Pb NMR signals were observed in LaPb 2 with a superconducting transition temperature of about 7 K. The width of the Pb NMR spectrum with an asymmetric line shape was rather narrower than those of Er-, Gd- and Ho-Pb 2 . The spin-lattice relaxation time of Pb nuclei was twice longer than that of Pb metal. La NMR spectrum had satellites due to the electric quadrupole interaction. These results show that each local environment at La or Pb site in LaPb 2 compound is uniquely determined, compared with those in randomly substituted alloys. ((orig.))

  4. Graphical programming for pulse automated NMR experiments

    International Nuclear Information System (INIS)

    Belmonte, S.B.; Oliveira, I.S.; Guimaraes, A.P.

    1999-01-01

    We describe a software program designed to control a broadband pulse Nuclear Magnetic Resonance (NMR) spectrometer used in zero-field NMR studies of magnetic metals. The software is written in the graphical language LabVIEW. This type of programming allows modifications and the inclusion of new routines to be easily made by the non-specialist, without changing the basic structure of the program. The program corrects for differences in the gain of the two acquisition channels [U (phase) and V (quadrature)], and automatic baseline subtraction. We present examples of measurements of NMR spectra, spin-echo decay (T 2 ), and quadrupolar oscillations, performed in magnetic intermetallic compounds. (author)

  5. The characterisation of polymers using pulsed NMR

    International Nuclear Information System (INIS)

    Charlesby, A.

    1983-01-01

    Broad line pulsed NMR is applied to obtain information on radiation-induced polymer changes and other aspects of polymer science based on the interpretation of spin-spin relaxation curves. Calculations are made to determine the molecular weight, the crosslink density of simple, low molecular weight, flexible polymers. For higher molecular weight polymers, a conclusion can be drawn on the concentrations of entangled and crosslinked units by means of pulsed NMR. Some typical applications of the technique are illustrated by the examples of polyethylenes, rubbers, filled polymeric systems and aqueous polyethylene oxide solutions. The morphology of polymers can be followed by pulsed NMR. (V.N.)

  6. MAS NMR of HIV-1 protein assemblies

    Science.gov (United States)

    Suiter, Christopher L.; Quinn, Caitlin M.; Lu, Manman; Hou, Guangjin; Zhang, Huilan; Polenova, Tatyana

    2015-04-01

    The negative global impact of the AIDS pandemic is well known. In this perspective article, the utility of magic angle spinning (MAS) NMR spectroscopy to answer pressing questions related to the structure and dynamics of HIV-1 protein assemblies is examined. In recent years, MAS NMR has undergone major technological developments enabling studies of large viral assemblies. We discuss some of these evolving methods and technologies and provide a perspective on the current state of MAS NMR as applied to the investigations into structure and dynamics of HIV-1 assemblies of CA capsid protein and of Gag maturation intermediates.

  7. N2,N2,N5,N5-Tetrakis(2-chloroethyl-3,4-dimethylthiophene-2,5-dicarboxamide

    Directory of Open Access Journals (Sweden)

    Yi-Dan Tang

    2010-01-01

    Full Text Available In the title compound, C16H22Cl4N2O2S, the two imide groups adopt a trans arrangement relative to the central thienyl ring, so the four terminal 2-chloroethyl arms adopt different orientations. In the crystal, molecules are linked by weak C—H...Cl and C—H...O hydrogen bonds into a three-dimensional network.

  8. NMR data-driven structure determination using NMR-I-TASSER in the CASD-NMR experiment

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Richard [Huazhong University of Science and Technology, School of Software Engineering (China); Wang, Yan [Huazhong University of Science and Technology, School of Life Science and Technology (China); Xue, Zhidong, E-mail: zdxue@hust.edu.cn [Huazhong University of Science and Technology, School of Software Engineering (China); Zhang, Yang, E-mail: zhng@umich.edu [University of Michigan, Department of Computational Medicine and Bioinformatics (United States)

    2015-08-15

    NMR-I-TASSER, an adaption of the I-TASSER algorithm combining NMR data for protein structure determination, recently joined the second round of the CASD-NMR experiment. Unlike many molecular dynamics-based methods, NMR-I-TASSER takes a molecular replacement-like approach to the problem by first threading the target through the PDB to identify structural templates which are then used for iterative NOE assignments and fragment structure assembly refinements. The employment of multiple templates allows NMR-I-TASSER to sample different topologies while convergence to a single structure is not required. Retroactive and blind tests of the CASD-NMR targets from Rounds 1 and 2 demonstrate that even without using NOE peak lists I-TASSER can generate correct structure topology with 15 of 20 targets having a TM-score above 0.5. With the addition of NOE-based distance restraints, NMR-I-TASSER significantly improved the I-TASSER models with all models having the TM-score above 0.5. The average RMSD was reduced from 5.29 to 2.14 Å in Round 1 and 3.18 to 1.71 Å in Round 2. There is no obvious difference in the modeling results with using raw and refined peak lists, indicating robustness of the pipeline to the NOE assignment errors. Overall, despite the low-resolution modeling the current NMR-I-TASSER pipeline provides a coarse-grained structure folding approach complementary to traditional molecular dynamics simulations, which can produce fast near-native frameworks for atomic-level structural refinement.

  9. NMR mechanisms in gel dosimetry

    International Nuclear Information System (INIS)

    Schreiner, L J

    2009-01-01

    Nuclear magnetic resonance was critical to the development of gel dosimetry, as it established the potential for three dimensional dosimetry with chemical dosimeter systems through magnetic resonance imaging [1]. In the last two decades MRI has served as the gold standard for imaging, while NMR relaxometry has played an important role in the development and understanding of the behaviour of new gel dosimetry systems. Therefore, an appreciation of the relaxation mechanisms determining the NMR behaviour of irradiated gel dosimeters is important for a full comprehension of a considerable component of the literature on gel dosimetry. A number of excellent papers have presented this important theory, this brief review will highlight some of the salient points made previously [1-5]. The spin relaxation of gel dosimeters (which determines the dose dependence in most conventional MR imaging) is determined principally by the protons on water molecules in the system. These water protons exist in different environments, or groups (see Figure 1): on bulk water, on water hydrating the chemical species that are being modified under irradiation, and on water hydrating the gel matrix used to spatially stabilize the dosimeter (e.g., gelatin, agarose, etc). The spin relaxation depends on the inherent relaxation rate of each spin group, that is, on the relaxation rate which would be observed for the specific group if it were isolated. Also, the different water environments are not isolated from each other, and the observed relaxation rate also depends on the rate of exchange of magnetization between the groups, and on the fraction of protons in each group. In fact, the water exchanges quickly between the environments, so that relaxation is in what is usually termed the fast exchange regime. In the limit of fast exchange, the relaxation of the water protons is well characterized by a single exponential and hence by a single apparent relaxation rate. In irradiated gel dosimeters this

  10. Structural investigations of substituted indolizine derivatives by NMR studies

    International Nuclear Information System (INIS)

    Furdui, Bianca; Dinica, Rodica; Demeunynck, Martine; Druta, Ioan

    2008-01-01

    Owing to the increasing importance of indolizine heterocycles in the field of biology and pharmacology we have synthesized and investigated the obtained heterocycles by NMR techniques. In order to investigate the substituent effects on the spectroscopic properties, a series of indolizine derivatives were studied by 1 H-NMR, 13 C-NMR and 2D NMR (GCOSY, GHMBC and GHMQC spectra). (authors)

  11. Continuous measurements of N2O emissions from arable fields

    Science.gov (United States)

    Wallman, Magdalena; Lammirato, Carlo; Rütting, Tobias; Delin, Sofia; Weslien, Per; Klemedtsson, Leif

    2017-04-01

    Agriculture represents 59 % of the anthropogenic nitrous oxide (N2O) emissions, according to the IPCC (Ciais et al. 2013). N2O emissions are typically irregular and vary widely in time and space, which makes it difficult to get a good representation of the emissions (Henault et al. 2012), particularly if measurements have low frequency and/or cover only a short time period. Manual measurements are, for practical reasons, often short-term and low-frequent, or restricted to periods where emissions are expected to be high, e.g. after fertilizing. However, the nature of N2O emissions, being largely unpredictable, calls for continuous or near-continuous measurements over long time periods. So far, rather few long-term, high resolution measurements of N2O emissions from arable fields are reported; among them are Flessa et al. (2002) and Senapati et al. (2016). In this study, we have a two-year data set (2015-2017) with hourly measurements from ten automatic chambers, covering unfertilized controls as well as different nitrogen fertilizer treatments. Grain was produced on the field, and effects of tillage, harvest and other cropping measures were covered. What we can see from the experiment is that (a) the unfertilized control plots seem to follow the same emission pattern as the fertilized plots, at a level similar to the standard mineral fertilized plots (120 kg N ha-1 yr-1) and (b) freeze/thaw emissions are comparable in size to emissions after fertilizing. These two findings imply that the importance of fertilizing to the overall N2O emissions from arable soils may be smaller than previously expected. References: Ciais, P., C. Sabine, G. Bala, L. Bopp, V. Brovkin, J. Canadell et al. 2013: Carbon and Other Biogeochemical Cycles. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung et

  12. NMR in the SPINE Structural Proteomics project.

    Science.gov (United States)

    Ab, E; Atkinson, A R; Banci, L; Bertini, I; Ciofi-Baffoni, S; Brunner, K; Diercks, T; Dötsch, V; Engelke, F; Folkers, G E; Griesinger, C; Gronwald, W; Günther, U; Habeck, M; de Jong, R N; Kalbitzer, H R; Kieffer, B; Leeflang, B R; Loss, S; Luchinat, C; Marquardsen, T; Moskau, D; Neidig, K P; Nilges, M; Piccioli, M; Pierattelli, R; Rieping, W; Schippmann, T; Schwalbe, H; Travé, G; Trenner, J; Wöhnert, J; Zweckstetter, M; Kaptein, R

    2006-10-01

    This paper describes the developments, role and contributions of the NMR spectroscopy groups in the Structural Proteomics In Europe (SPINE) consortium. Focusing on the development of high-throughput (HTP) pipelines for NMR structure determinations of proteins, all aspects from sample preparation, data acquisition, data processing, data analysis to structure determination have been improved with respect to sensitivity, automation, speed, robustness and validation. Specific highlights are protonless (13)C-direct detection methods and inferential structure determinations (ISD). In addition to technological improvements, these methods have been applied to deliver over 60 NMR structures of proteins, among which are five that failed to crystallize. The inclusion of NMR spectroscopy in structural proteomics pipelines improves the success rate for protein structure determinations.

  13. NMR study of Albemoschus esculentus characterization

    International Nuclear Information System (INIS)

    Bathista, A.L.B.S; Silva, E.O.; Nogueira, Jose de S.; Tavares, M.I.B.

    2001-01-01

    The investigation of the main compounds presented in the Albemoschus esculentus has been carried out employing nuclear magnetic resonance spectroscopy (NMR), using solution and solid state NMR when it one was necessary. The evaluation of NMR data allowed us to characterize the main type of components presented in this kind of sample. It was necessary to use a total information from solid state NMR and also the solution response. From these information we could get that four main components were presented in this sample. One in the shell, that is cellulose, another one between the shell and seeds that is a polysaccharide and in the seed two components were found one is a starch and the second one is an oil, a triacylglycerol. These components are responsible by its physical chemistry properties. (author)

  14. Bayesian Peak Picking for NMR Spectra

    KAUST Repository

    Cheng, Yichen

    2014-02-01

    Protein structure determination is a very important topic in structural genomics, which helps people to understand varieties of biological functions such as protein-protein interactions, protein–DNA interactions and so on. Nowadays, nuclear magnetic resonance (NMR) has often been used to determine the three-dimensional structures of protein in vivo. This study aims to automate the peak picking step, the most important and tricky step in NMR structure determination. We propose to model the NMR spectrum by a mixture of bivariate Gaussian densities and use the stochastic approximation Monte Carlo algorithm as the computational tool to solve the problem. Under the Bayesian framework, the peak picking problem is casted as a variable selection problem. The proposed method can automatically distinguish true peaks from false ones without preprocessing the data. To the best of our knowledge, this is the first effort in the literature that tackles the peak picking problem for NMR spectrum data using Bayesian method.

  15. NMR and optical studies of piezoelectric polymers

    International Nuclear Information System (INIS)

    Schmidt, V.H.; Tuthill, G.F.

    1993-01-01

    Progress is reported in several areas dealing with piezoelectric (electroactive) polymers (mostly vinylidene fluoride, trifluoroethylene, copolymers, PVF 2 ) and liquid crystals. Optical studies, neutron scattering, NMR, thermal, theory and modeling were done

  16. High resolution NMR theory and chemical applications

    CERN Document Server

    Becker, Edwin D

    2012-01-01

    High Resolution NMR: Theory and Chemical Applications discusses the principles and theory of nuclear magnetic resonance and how this concept is used in the chemical sciences. This book is written at an intermediate level, with mathematics used to augment verbal descriptions of the phenomena. This text pays attention to developing and interrelating four approaches - the steady state energy levels, the rotating vector picture, the density matrix, and the product operator formalism. The style of this book is based on the assumption that the reader has an acquaintance with the general principles of quantum mechanics, but no extensive background in quantum theory or proficiency in mathematics is required. This book begins with a description of the basic physics, together with a brief account of the historical development of the field. It looks at the study of NMR in liquids, including high resolution NMR in the solid state and the principles of NMR imaging and localized spectroscopy. This book is intended to assis...

  17. NMR studies of cerebral metabolism in vivo

    International Nuclear Information System (INIS)

    Prichard, J.W.

    1986-01-01

    The nature and extent of the potential synergism between PET and NMR methods is not yet well appreciated in the biomedical community. The long-range interest of medical neurobiology will be well served by efforts of PET and NMR scientists to follow each others' work so that opportunities for productive interchange can be efficiently exploited. Appreciation of the synergism by the rest of the biomedical community will follow naturally. PET is said by the people doing it to be still in its infancy, for they are more concerned with advancing their discipline than with admiring its already impressive achievements. On the scale of the same developmental metaphor, many NMR methods for studying the living human brain are still in utero. The best way to provide the reader a sense of the current status and future course of NMR research in medical neurobiology is by discussion of published in vivo studies. Such a discussion, adapted from another article is what follows

  18. Development of Two-Dimensional NMR

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 20; Issue 11. Development of Two-Dimensional NMR: Strucure Determination of Biomolecules in Solution. Anil Kumar. General Article Volume 20 Issue 11 November 2015 pp 995-1002 ...

  19. NMR spectroscopy of coal pyrolysis products

    Energy Technology Data Exchange (ETDEWEB)

    Polonov, V.M.; Kalabin, G.A.; Kushnarev, D.F.; Shevchenko, G.G.

    1985-12-01

    The authors consider the scope for using H 1 and C 13 NMR spectroscopy to describe the products from coal pyrolysis and hydrogenization. The accuracy of the structural information provided by the best NMR methods is also considered. The stuctural parameters derived from H 1 and C 13 NMR spectra are presented. Results demonstrate the high accuracy and sensitivity of the structural information provided by H 1 AND C 13 NMR spectra for coal products. There are substantial structural differences between the soluble products from medium-temperature coking of Cheremkhov coal and high-speed pyrolysis of Kan-Acha coal, and also differences in behavior during hydrogenation. These differences are related to the structure of the organic matter in the initial coal and to differences in the pyrolysis mechanisms.

  20. Non-renormalization theorems andN=2 supersymmetric backgrounds

    International Nuclear Information System (INIS)

    Butter, Daniel; Wit, Bernard de; Lodato, Ivano

    2014-01-01

    The conditions for fully supersymmetric backgrounds of general N = 2 locally supersymmetric theories are derived based on the off-shell superconformal multiplet calculus. This enables the derivation of a non-renormalization theorem for a large class of supersymmetric invariants with higher-derivative couplings. The theorem implies that the invariant and its first order variation must vanish in a fully supersymmetric background. The conjectured relation of one particular higher-derivative invariant with a specific five-dimensional invariant containing the mixed gauge-gravitational Chern-Simons term is confirmed

  1. An N=2 dual pair and a phase transition

    International Nuclear Information System (INIS)

    Aspinwall, P.S.

    1996-01-01

    We carefully analyze the N=2 dual pair of string theories in four dimensions introduced by Ferrara, Harvey, Strominger and Vafa. The analysis shows that a second discrete degree of freedom must be switched on in addition to the known ''Wilson line'' to achieve a non-perturbatively consistent theory. We also identify the phase transition this model undergoes into another dual pair via a process analogous to a conifold transition. This provides the first known example of a phase transition which is understood from both the type II and the heterotic string picture. (orig.)

  2. The exact superpartners of N = 2 supergravity solitons

    International Nuclear Information System (INIS)

    Aichelburg, P.C.; Embacher, F.

    1986-01-01

    By applying long-range N = 2 supergauge transformations to the Majumdar-Papapetrou configurations, the set of all superpartners to the bosonic multi-solitons is exhibited. The resulting configuration is parametrized by two additional complex Grassmann numbers. Apart from mass and electric (possibly magnetic) charge it carries a supercharge which is algebraically constrained due to the central charges in the supersymmetry algebra. The supercharge gives rise to an 'intrinsic' angular momentum. Similar to the Kerr metric, the configuration is stationary with an anomalous magnetic moment. (Author)

  3. Local rings of singularities and N=2 supersymmetric quantum mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Klimek, S.; Lesniewski, A. (Harvard Univ., Cambridge, MA (USA))

    1991-02-01

    We investigate the Kaehler structure arising in n-component, N = 2 supersymmetric quantum mechanics. We define L{sup 2}-cohomology groups of a modified {delta}-operator and relate them to the corresponding spaces of harmonic forms. We prove that the cohomology is concentrated in the middle dimension, and is isomorphic to the direct sum of the local rings of the singularities of the superpotential. In the physics language, this means that the number of ground states is equal to the absolute value of the index of the supercharge, and each ground state contains exactly n fermions. (orig.).

  4. Chains of N=2, D=4 heterotic type II duals

    CERN Document Server

    Aldazabal, G; Font, A; Quevedo, Fernando

    1996-01-01

    We report on a search for N=2 heterotic strings that are dual candidates of type II compactifications on Calabi-Yau threefolds described as K3 fibrations. We find many new heterotic duals by using standard orbifold techniques. The associated type II compactifications fall into chains in which the proposed duals are heterotic compactifications related one another by a sequential Higgs mechanism. This breaking in the heterotic side typically involves the sequence SU(4)\\rightarrow SU(3)\\rightarrow SU(2)\\rightarrow 0, while in the type II side the weights of the complex hypersurfaces and the structure of the K3 quotient singularities also follow specific patterns.

  5. Role of steps in N-2 activation on Ru(0001)

    DEFF Research Database (Denmark)

    Dahl, Søren; Logadottir, Ashildur; Egeberg, Rasmus

    1999-01-01

    Using adsorption experiments and density functional calculations we show that N-2 dissociation on the Ru(0001) surface is totally dominated by steps. The measured adsorption rate at the steps is at least 9 orders of magnitude higher than on the terraces at 500 K, and the corresponding calculated ...... difference in activation energy is 1.5 eV. The low barrier at the step is shown to be due to a combination of electronic and geometrical effects. The consequences for Ru as a catalyst for ammonia synthesis are discussed....

  6. Two-dimensional N = 2 Super-Yang-Mills Theory

    Science.gov (United States)

    August, Daniel; Wellegehausen, Björn; Wipf, Andreas

    2018-03-01

    Supersymmetry is one of the possible scenarios for physics beyond the standard model. The building blocks of this scenario are supersymmetric gauge theories. In our work we study the N = 1 Super-Yang-Mills (SYM) theory with gauge group SU(2) dimensionally reduced to two-dimensional N = 2 SYM theory. In our lattice formulation we break supersymmetry and chiral symmetry explicitly while preserving R symmetry. By fine tuning the bar-mass of the fermions in the Lagrangian we construct a supersymmetric continuum theory. To this aim we carefully investigate mass spectra and Ward identities, which both show a clear signal of supersymmetry restoration in the continuum limit.

  7. Lagrangians of N=2 supergravity-matter systems

    International Nuclear Information System (INIS)

    Wit, B. de; Proeyen, A. van; Lauwers, P.G.

    1984-12-01

    We present explicit expressions for general actions of vector and scalar multiplets coupled to N=2 supergravity. We outline their construction which is based on the superconformal tensor calculus. The vector multiplets may be associated with a gauge group G which may also act on the scalar multiplets. The latter are naturally described in terms of quaternions; in the simplest case their kinetic terms define a nonlinear sigma model of a quaternionic projective space. We give an extension of the vector multiplet action which is not obtained from a chiral superspace density, and contains a Chern-Simons-type term. Transformation rules are given and the conditions for supersymmetry breaking are defined. (orig.)

  8. Periodic Schur process, cylindric partitions and N=2* theory

    International Nuclear Information System (INIS)

    Iqbal, Amer; Kozcaz, Can; Sohail, Tanweer

    2011-01-01

    Type IIA string theory compactified on an elliptic CY3-fold gives rise to N=2U(1) gauge theory with an adjoint hypermultiplet. We study the refined open and closed topological string partition functions of this geometry using the refined topological vertex. We show that these partition functions, open and closed, are examples of periodic Schur process and are related to the generating function of the cylindric partitions if the Kaehler parameters are quantized in units of string coupling. The level-rank duality appears as the exchange symmetry of the two Kaehler parameters of the elliptic CY3-fold.

  9. NMR study of hydride systems

    International Nuclear Information System (INIS)

    Peretz, M.

    1980-02-01

    The hydrides of thorium (ThH 2 , Th 4 H 15 and Th 4 D 15 ) and the intermetallic compound system (Zr(Vsub(1-x)Cosub(x)) 2 and its hydrides were investigated using the nuclear magnetic resonance (NMR) technique. From the results for the thorium hydride samples it was concluded that the density of states at the Fermi level n(Esub(f)) is higher in Th 4 H 15 than in ThH 2 ; there is an indirect reaction between the protons and the d electrons belonging to the Th atoms in Th 4 H 15 ; n(E) has a sharp structure near Esub(f). It was also found that the hydrogen diffusion mechanism changes with temperature. From the results for the intermetallic compound system conclusions were drawn concerning variations in the electronic structure, which explain the behavior of the system. In hydrogen diffusion studies in several samples it was found that Co atoms slow the diffusion rate. Quadrupole spectra obtained at low temperatures show that the H atoms preferably occupy tetrahedral sites formed by three V atoms and one Z atom. (H.K.)

  10. Frontiers of NMR in Molecular Biology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-08-25

    NMR spectroscopy is expanding the horizons of structural biology by determining the structures and describing the dynamics of blobular proteins in aqueous solution, as well as other classes of proteins including membrane proteins and the polypeptides that form the aggregates diagnostic of prion and amyloid diseases. Significant results are also emerging on DNA and RNA oligomers and their complexes with proteins. This meeting focused attention on key structural questions emanating from molecular biology and how NMR spectroscopy can be used to answer them.

  11. NMR studies of multiphase flows II

    Energy Technology Data Exchange (ETDEWEB)

    Altobelli, S.A.; Caprihan, A.; Fukushima, E. [Lovelace Institutes, Albuquerque, NM (United States)] [and others

    1995-12-31

    NMR techniques for measurements of spatial distribution of material phase, velocity and velocity fluctuation are being developed and refined. Versions of these techniques which provide time average liquid fraction and fluid phase velocity have been applied to several concentrated suspension systems which will not be discussed extensively here. Technical developments required to further extend the use of NMR to the multi-phase flow arena and to provide measurements of previously unobtainable parameters are the focus of this report.

  12. observed by high pressure NMR and NQR

    Indian Academy of Sciences (India)

    Akogun, Hyogo 678-1297, Japan. ∗. Email: kohara@sci.himeji tech.ac.jp. Abstract. NMR and NQR studies on two interesting systems (URu2Si2, CeTIn5) were performed under high pressure. (1) URu2Si2: In the pressure range 3.0 to 8.3 kbar, we have observed new 29Si. NMR signals arising from the antiferromagnetic ...

  13. NMRbox: A Resource for Biomolecular NMR Computation.

    Science.gov (United States)

    Maciejewski, Mark W; Schuyler, Adam D; Gryk, Michael R; Moraru, Ion I; Romero, Pedro R; Ulrich, Eldon L; Eghbalnia, Hamid R; Livny, Miron; Delaglio, Frank; Hoch, Jeffrey C

    2017-04-25

    Advances in computation have been enabling many recent advances in biomolecular applications of NMR. Due to the wide diversity of applications of NMR, the number and variety of software packages for processing and analyzing NMR data is quite large, with labs relying on dozens, if not hundreds of software packages. Discovery, acquisition, installation, and maintenance of all these packages is a burdensome task. Because the majority of software packages originate in academic labs, persistence of the software is compromised when developers graduate, funding ceases, or investigators turn to other projects. To simplify access to and use of biomolecular NMR software, foster persistence, and enhance reproducibility of computational workflows, we have developed NMRbox, a shared resource for NMR software and computation. NMRbox employs virtualization to provide a comprehensive software environment preconfigured with hundreds of software packages, available as a downloadable virtual machine or as a Platform-as-a-Service supported by a dedicated compute cloud. Ongoing development includes a metadata harvester to regularize, annotate, and preserve workflows and facilitate and enhance data depositions to BioMagResBank, and tools for Bayesian inference to enhance the robustness and extensibility of computational analyses. In addition to facilitating use and preservation of the rich and dynamic software environment for biomolecular NMR, NMRbox fosters the development and deployment of a new class of metasoftware packages. NMRbox is freely available to not-for-profit users. Copyright © 2017 Biophysical Society. All rights reserved.

  14. A microscale protein NMR sample screening pipeline

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, Paolo; Swapna, G. V. T.; Huang, Yuanpeng J.; Aramini, James M. [State University of New Jersey, Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, Rutgers (United States); Anklin, Clemens [Bruker Biospin Corporation (United States); Conover, Kenith; Hamilton, Keith; Xiao, Rong; Acton, Thomas B.; Ertekin, Asli; Everett, John K.; Montelione, Gaetano T., E-mail: guy@cabm.rutgers.ed [State University of New Jersey, Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, Rutgers (United States)

    2010-01-15

    As part of efforts to develop improved methods for NMR protein sample preparation and structure determination, the Northeast Structural Genomics Consortium (NESG) has implemented an NMR screening pipeline for protein target selection, construct optimization, and buffer optimization, incorporating efficient microscale NMR screening of proteins using a micro-cryoprobe. The process is feasible because the newest generation probe requires only small amounts of protein, typically 30-200 {mu}g in 8-35 {mu}l volume. Extensive automation has been made possible by the combination of database tools, mechanization of key process steps, and the use of a micro-cryoprobe that gives excellent data while requiring little optimization and manual setup. In this perspective, we describe the overall process used by the NESG for screening NMR samples as part of a sample optimization process, assessing optimal construct design and solution conditions, as well as for determining protein rotational correlation times in order to assess protein oligomerization states. Database infrastructure has been developed to allow for flexible implementation of new screening protocols and harvesting of the resulting output. The NESG micro NMR screening pipeline has also been used for detergent screening of membrane proteins. Descriptions of the individual steps in the NESG NMR sample design, production, and screening pipeline are presented in the format of a standard operating procedure.

  15. O-17 NMR measurement of water

    International Nuclear Information System (INIS)

    Fukazawa, Nobuyuki

    1990-01-01

    Recently, attention has been paid to the various treatment of water and the utilization of water by magnetic treatment, electric field treatment and so on. It has been said that by these treatments, the change in the properties of water arises. The state of this treated water cannot be explained by the properties of water from conventional physical and chemical standpoints. In addition, the method of measurement of whether the change arose or not is not yet determined. It is necessary to establish the method of measurement for the basic state of water. In this study, O-17 NMR which observes the state of water directly at molecular or atomic level was investigated as the method of measuring water. The measurement of O-17 NMR was carried out with a JNR 90Q FT NMR of Fourier transformation type of JEOL Ltd. The experimental method and the results are reported. The result of measurement of the O-17 NMR spectrum for distilled ion exchange water is shown. It is know that it has very wide line width as compared with the NMR spectra of protons and C-13. The relative sensitivity of O-17 observation is about 1/100,000 of that of protons. As to the information on the state of water obtained by O-17 NMR, there are chemical shift and line width. As temperature rose, the line width showed decrease, which seemed to be related to the decrease of hydrogen combination. (K.I.)

  16. Purification and H-1 NMR spectroscopic characterization of phase II metabolites of tolfenamic acid

    DEFF Research Database (Denmark)

    Sidelmann, U. G.; Christiansen, E.; Krogh, L.

    1997-01-01

    samples obtained on days 7 to 10 from a human volunteer after oral administration of 200 mg of the drug three times per day (steady-state plasma concentration). The metabolites of tolfenamic acid were initially concentrated by preparative solid phase extraction (PSPE) chromatography, thereby removing...... the endogenous polar compounds that are present in the urine. The individual metabolites were purified by preparative high performance liquid chromatography (HPLC) and then identified using H-1 NMR, Both one- and two-dimensional NMR experiments were performed to identify the phase II metabolites of tolfenamic......), and N-(2-methyl-4-hydroxyphenyl)-anthranilic acid (11) were identified. The phase II metabolites (5-11) had not previously been identified in urine from humans administered tolfenamic acid. The phase I metabolites of the glucuronides 7, 8, 10, and 11 were identified here for the first time. An HPLC...

  17. Excessive use of nitrogen in Chinese agriculture results in high N2O/(N2O+N2) product ratio of denitrification, primarily due to acidification of the soils

    Science.gov (United States)

    Qu, Zhi; Wang, Jingguo; Almøy, Trygve; Bakken, Lars R

    2014-01-01

    China is the world's largest producer and consumer of fertilizer N, and decades of overuse has caused nitrate leaching and possibly soil acidification. We hypothesized that this would enhance the soils' propensity to emit N2O from denitrification by reducing the expression of the enzyme N2O reductase. We investigated this by standardized oxic/anoxic incubations of soils from five long-term fertilization experiments in different regions of China. After adjusting the nitrate concentration to 2 mM, we measured oxic respiration (R), potential denitrification (D), substrate-induced denitrification, and the denitrification product stoichiometry (NO, N2O, N2). Soils with a history of high fertilizer N levels had high N2O/(N2O+N2) ratios, but only in those field experiments where soil pH had been lowered by N fertilization. By comparing all soils, we found a strong negative correlation between pH and the N2O/(N2O+N2) product ratio (r2 = 0.759, P soil pH. The immediate effect of liming acidified soils was lowered N2O/(N2O+N2) ratios. The results provide evidence that soil pH has a marginal direct effect on potential denitrification, but that it is the master variable controlling the percentage of denitrified N emitted as N2O. It has been known for long that low pH may result in high N2O/(N2O+N2) product ratios of denitrification, but our documentation of a pervasive pH-control of this ratio across soil types and management practices is new. The results are in good agreement with new understanding of how pH may interfere with the expression of N2O reductase. We argue that the management of soil pH should be high on the agenda for mitigating N2O emissions in the future, particularly for countries where ongoing intensification of plant production is likely to acidify the soils. PMID:24249526

  18. Basics of spectroscopic instruments. Hardware of NMR spectrometer

    International Nuclear Information System (INIS)

    Sato, Hajime

    2009-01-01

    NMR is a powerful tool for structure analysis of small molecules, natural products, biological macromolecules, synthesized polymers, samples from material science and so on. Magnetic Resonance Imaging (MRI) is applicable to plants and animals Because most of NMR experiments can be done by an automation mode, one can forget hardware of NMR spectrometers. It would be good to understand features and performance of NMR spectrometers. Here I present hardware of a modern NMR spectrometer which is fully equipped with digital technology. (author)

  19. 33S NMR cryogenic probe for taurine detection

    Science.gov (United States)

    Hobo, Fumio; Takahashi, Masato; Maeda, Hideaki

    2009-03-01

    With the goal of a S33 nuclear magnetic resonance (NMR) probe applicable to in vivo NMR on taurine-biological samples, we have developed the S33 NMR cryogenic probe, which is applicable to taurine solutions. The NMR sensitivity gain relative to a conventional broadband probe is as large as 3.5. This work suggests that improvements in the preamplifier could allow NMR measurements on 100 μM taurine solutions, which is the level of sensitivity necessary for biological samples.

  20. Petrophysical properties of greensand as predicted from NMR measurements

    DEFF Research Database (Denmark)

    Hossain, Zakir; Grattoni, Carlos A.; Solymar, Mikael

    2011-01-01

    ABSTRACT: Nuclear magnetic resonance (NMR) is a useful tool in reservoir evaluation. The objective of this study is to predict petrophysical properties from NMR T2 distributions. A series of laboratory experiments including core analysis, capillary pressure measurements, NMR T2 measurements...... with macro-pores. Permeability may be predicted from NMR by using Kozeny's equation when surface relaxivity is known. Capillary pressure drainage curves may be predicted from NMR T2 distribution when pore size distribution within a sample is homogeneous....

  1. Chiral trace relations in Ω-deformed N=2 theories

    Energy Technology Data Exchange (ETDEWEB)

    Beccaria, Matteo; Fachechi, Alberto; Macorini, Guido [Dipartimento di Matematica e Fisica Ennio De Giorgi,Università del Salento, Via Arnesano, 73100 Lecce (Italy); INFN - Sezione di LecceVia Arnesano, 73100 Lecce (Italy)

    2017-05-04

    We consider N=2SU(2) gauge theories in four dimensions (pure or mass deformed) and discuss the properties of the simplest chiral observables in the presence of a generic Ω-deformation. We compute them by equivariant localization and analyze the structure of the exact instanton corrections to the classical chiral ring relations. We predict exact relations valid at all instanton number among the traces 〈Trφ{sup n}〉, where φ is the scalar field in the gauge multiplet. In the Nekrasov-Shatashvili limit, such relations may be explained in terms of the available quantized Seiberg-Witten curves. Instead, the full two-parameter deformation enjoys novel features and the ring relations require non trivial additional derivative terms with respect to the modular parameter. Higher rank groups are briefly discussed emphasizing non-factorization of correlators due to the Ω-deformation. Finally, the structure of the deformed ring relations in the N=2{sup ⋆} theory is analyzed from the point of view of the Alday-Gaiotto-Tachikawa correspondence proving consistency as well as some interesting universality properties.

  2. Expanding the landscape of N=2 rank 1 SCFTs

    International Nuclear Information System (INIS)

    Argyres, Philip C.; Lotito, Matteo; Lü, Yongchao; Martone, Mario

    2016-01-01

    We refine our previous proposal http://arxiv.org/abs/1505.04814http://arxiv.org/abs/1601.00011P. Argyres, M. Lotito, Y. Lü and M. Martone, Geometric constraints on the space of N=2 SCFTs III: enhanced Coulomb branches and central charges, to appear. for systematically classifying 4d rank-1 N=2 SCFTs by constructing their possible Coulomb branch geometries. Four new recently discussed rank-1 theories http://dx.doi.org/10.1007/JHEP03(2016)083http://arxiv.org/abs/1601.02077, including novel N=3 SCFTs, sit beautifully in our refined classification framework. By arguing for the consistency of their RG flows we can make a strong case for the existence of at least four additional rank-1 SCFTs, nearly doubling the number of known rank-1 SCFTs. The refinement consists of relaxing the assumption that the flavor symmetries of the SCFTs have no discrete factors. This results in an enlarged (but finite) set of possible rank-1 SCFTs. Their existence can be further constrained using consistency of their central charges and RG flows.

  3. Gauge-independent renormalization of the N2HDM

    Science.gov (United States)

    Krause, Marcel; López-Val, David; Mühlleitner, Margarete; Santos, Rui

    2017-12-01

    The Next-to-Minimal 2-Higgs-Doublet Model (N2HDM) is an interesting benchmark model for a Higgs sector consisting of two complex doublet and one real singlet fields. Like the Next-to-Minimal Supersymmetric extension (NMSSM) it features light Higgs bosons that could have escaped discovery due to their singlet admixture. Thereby, the model allows for various different Higgs-to-Higgs decay modes. Contrary to the NMSSM, however, the model is not subject to supersymmetric relations restraining its allowed parameter space and its phenomenology. For the correct determination of the allowed parameter space, the correct interpretation of the LHC Higgs data and the possible distinction of beyond-the-Standard Model Higgs sectors higher order corrections to the Higgs boson observables are crucial. This requires not only their computation but also the development of a suitable renormalization scheme. In this paper we have worked out the renormalization of the complete N2HDM and provide a scheme for the gauge-independent renormalization of the mixing angles. We discuss the renormalization of the Z_2 soft breaking parameter m 12 2 and the singlet vacuum expectation value v S . Both enter the Higgs self-couplings relevant for Higgs-to-Higgs decays. We apply our renormalization scheme to different sample processes such as Higgs decays into Z bosons and decays into a lighter Higgs pair. Our results show that the corrections may be sizable and have to be taken into account for reliable predictions.

  4. The diversity of the N2O reducers matters for the N2O:N2 denitrification end-product ratio across an annual and a perennial cropping system.

    Science.gov (United States)

    Domeignoz-Horta, Luiz A; Spor, Aymé; Bru, David; Breuil, Marie-Christine; Bizouard, Florian; Léonard, Joël; Philippot, Laurent

    2015-01-01

    Agriculture is the main source of terrestrial emissions of N2O, a potent greenhouse gas and the main cause of ozone layer depletion. The reduction of N2O into N2 by microorganisms carrying the nitrous oxide reductase gene (nosZ) is the only biological process known to eliminate this greenhouse gas. Recent studies showed that a previously unknown clade of N2O-reducers was related to the capacity of the soil to act as an N2O sink, opening the way for new strategies to mitigate emissions. Here, we investigated whether the agricultural practices could differently influence the two N2O reducer clades with consequences for denitrification end-products. The abundance of N2O-reducers and producers was quantified by real-time PCR, and the diversity of both nosZ clades was determined by 454 pyrosequencing. Potential N2O production and potential denitrification activity were used to calculate the denitrification gaseous end-product ratio. Overall, the results showed limited differences between management practices but there were significant differences between cropping systems in both the abundance and structure of the nosZII community, as well as in the [rN2O/r(N2O+N2)] ratio. More limited differences were observed in the nosZI community, suggesting that the newly identified nosZII clade is more sensitive than nosZI to environmental changes. Potential denitrification activity and potential N2O production were explained mainly by the soil properties while the diversity of the nosZII clade on its own explained 26% of the denitrification end-product ratio, which highlights the importance of understanding the ecology of this newly identified clade of N2O reducers for mitigation strategies.

  5. Validation of ACE-FTS N2O measurements

    Directory of Open Access Journals (Sweden)

    G. P. Stiller

    2008-08-01

    Full Text Available The Atmospheric Chemistry Experiment (ACE, also known as SCISAT, was launched on 12 August 2003, carrying two instruments that measure vertical profiles of atmospheric constituents using the solar occultation technique. One of these instruments, the ACE Fourier Transform Spectrometer (ACE-FTS, is measuring volume mixing ratio (VMR profiles of nitrous oxide (N2O from the upper troposphere to the lower mesosphere at a vertical resolution of about 3–4 km. In this study, the quality of the ACE-FTS version 2.2 N2O data is assessed through comparisons with coincident measurements made by other satellite, balloon-borne, aircraft, and ground-based instruments. These consist of vertical profile comparisons with the SMR, MLS, and MIPAS satellite instruments, multiple aircraft flights of ASUR, and single balloon flights of SPIRALE and FIRS-2, and partial column comparisons with a network of ground-based Fourier Transform InfraRed spectrometers (FTIRs. Between 6 and 30 km, the mean absolute differences for the satellite comparisons lie between −42 ppbv and +17 ppbv, with most within ±20 ppbv. This corresponds to relative deviations from the mean that are within ±15%, except for comparisons with MIPAS near 30 km, for which they are as large as 22.5%. Between 18 and 30 km, the mean absolute differences for the satellite comparisons are generally within ±10 ppbv. From 30 to 60 km, the mean absolute differences are within ±4 ppbv, and are mostly between −2 and +1 ppbv. Given the small N2O VMR in this region, the relative deviations from the mean are therefore large at these altitudes, with most suggesting a negative bias in the ACE-FTS data between 30 and 50 km. In the comparisons with the FTIRs, the mean relative differences between the ACE-FTS and FTIR partial columns (which cover a mean altitude range of 14 to 27 km are within ±5.6% for eleven of the twelve contributing stations. This mean relative difference is negative at ten stations

  6. Superconformal theories d=2,N=2 and w superalgebras; Theories superconformes d=2,N=2 et superalgebres w

    Energy Technology Data Exchange (ETDEWEB)

    Gourmelen, S

    1997-12-19

    Conformal invariance and supersymmetry are the two great fields of theoretical physics concerned with two dimensional conformal theories. These two dimensional conformal theories are here studied within the frame of supersymmetric N=2 extension in a no-metric formalism. The (2,0) and (2,2) Riemann super-surfaces (SSR) are characterized by Beltrami superfields. On such a SSR a superconformal field theory owns a local invariance linked to both diffeomorphisms and U-gauge symmetry. The study of these symmetries is carried out in the BRS formalism and applied to quantum anomaly determination. Sigma models are built on (2,0) and (2,2) SSR. Moreover the projective structures of SSR,N=2 are analysed by using a Schwartz connection which enables us to build super-differential covariant operators under superconformal transformations defined on SSR. These operators are categorized and their matrix analysis leads, owing to null curvature condition, to the study of W superalgebra. (author) 130 refs.

  7. Continuous Flow 1H and 13C NMR Spectroscopy in Microfluidic Stripline NMR Chips

    NARCIS (Netherlands)

    Oosthoek-de Vries, Anna Jo; Bart, Jacob; Tiggelaar, Roald M.; Janssen, Johannes W.G.; van Bentum, Jan (P.J.M.); Gardeniers, Han J.G.E.; Kentgens, Arno P.M.

    2017-01-01

    Microfluidic stripline NMR technology not only allows for NMR experiments to be performed on small sample volumes in the submicroliter range, but also experiments can easily be performed in continuous flow because of the stripline's favorable geometry. In this study we demonstrate the possibility of

  8. Performance of the WeNMR CS-Rosetta3 web server in CASD-NMR.

    Science.gov (United States)

    van der Schot, Gijs; Bonvin, Alexandre M J J

    2015-08-01

    We present here the performance of the WeNMR CS-Rosetta3 web server in CASD-NMR, the critical assessment of automated structure determination by NMR. The CS-Rosetta server uses only chemical shifts for structure prediction, in combination, when available, with a post-scoring procedure based on unassigned NOE lists (Huang et al. in J Am Chem Soc 127:1665-1674, 2005b, doi: 10.1021/ja047109h). We compare the original submissions using a previous version of the server based on Rosetta version 2.6 with recalculated targets using the new R3FP fragment picker for fragment selection and implementing a new annotation of prediction reliability (van der Schot et al. in J Biomol NMR 57:27-35, 2013, doi: 10.1007/s10858-013-9762-6), both implemented in the CS-Rosetta3 WeNMR server. In this second round of CASD-NMR, the WeNMR CS-Rosetta server has demonstrated a much better performance than in the first round since only converged targets were submitted. Further, recalculation of all CASD-NMR targets using the new version of the server demonstrates that our new annotation of prediction quality is giving reliable results. Predictions annotated as weak are often found to provide useful models, but only for a fraction of the sequence, and should therefore only be used with caution.

  9. Use of NMR and NMR Prediction Software to Identify Components in Red Bull Energy Drinks

    Science.gov (United States)

    Simpson, Andre J.; Shirzadi, Azadeh; Burrow, Timothy E.; Dicks, Andrew P.; Lefebvre, Brent; Corrin, Tricia

    2009-01-01

    A laboratory experiment designed as part of an upper-level undergraduate analytical chemistry course is described. Students investigate two popular soft drinks (Red Bull Energy Drink and sugar-free Red Bull Energy Drink) by NMR spectroscopy. With assistance of modern NMR prediction software they identify and quantify major components in each…

  10. New methods for the correction of 31P NMR spectra in in vivo NMR spectroscopy

    International Nuclear Information System (INIS)

    Starcuk, Z.; Bartusek, K.; Starcuk, Z. jr.

    1994-01-01

    The new methods for the correction of 31 P NMR spectra in vivo NMR spectroscopy have been performed. A method for the baseline correction of the spectra which represents a combination of time-domain and frequency-domain has been discussed.The method is very fast and efficient for minimization of base line artifacts of biological tissues impact

  11. The transformations between N= 2 supersymmetric Korteweg-de Vries and Harry Dym equations

    International Nuclear Information System (INIS)

    Tian Kai; Liu, Q. P.

    2012-01-01

    The N= 2 supercomformal transformations are employed to study supersymmetric integrable systems. It is proved that two known N= 2 supersymmetric Harry Dym equations are transformed into two N= 2 supersymmetric modified Korteweg-de Vries equations, thus are connected with two N= 2 supersymmetric Korteweg-de Vries equations.

  12. Anomalous broadening of the N2+ first negative band system

    International Nuclear Information System (INIS)

    Robben, F.; Cattolica, R.; Coe, D.; Talbot, L.

    1976-01-01

    Analysis of the fluorescence excited by a high energy electron beam has become a standard technique for measurement of density, rotational temperature of nitrogen, and translational temperature of helium and argon in rarefied gas dynamics. To obtain translational temperature the Doppler broadening of the fluorescence is determined by measuring the spectral line shape with a Fabry-Perot interferometer. To apply this technique to nitrogen a single rotational line must be selected from the band spectrum for analysis by the Fabry-Perot interferometer. As supported by extensive additional measurements, there is an anomalous broadening of the rotational lines of the N 2 + first negative band system with a width equivalent to about a 70 0 K translational temperature of nitrogen. It appears that the line width of approximately 0.03 cm -1 is an inherent property of this nitrogen band when excited by electron impact directly from the ground state

  13. New Higgs transitions between dual N=2 string models

    International Nuclear Information System (INIS)

    Berglund, P.; Katz, S.; Klemm, A.; Mayr, P.

    1997-01-01

    We describe a new kind of transition between topologically distinct N=2 type II Calabi-Yau vacua through points with enhanced non-abelian gauge symmetries together with fundamental charged matter hyper multiplets. We connect the appearance of matter to the local geometry of the singularity and discuss the relation between the instanton numbers of the Calabi-Yau manifolds taking part in the transition. In a dual heterotic string theory on K3 x T 2 the process corresponds to Higgsing a semi-classical gauge group or equivalently to a variation of the gauge bundle. In special cases the situation reduces to simple conifold transitions in the Coulomb phase of the non-abelian gauge symmetries. (orig.)

  14. Measuring small distances in N=2 sigma models

    International Nuclear Information System (INIS)

    Aspinwall, Paul S.; Greene, Brian R.; Morrison, David R.

    1994-01-01

    We analyze global aspects of the moduli space of Kaehler forms for N=(2,2) conformal σ-models. Using algebraic methods and mirror symmetry we study extensions of the mathematical notion of length (as specified by a Kaehler structure) to conformal field theory and calculate the way in which lengths change as the moduli fields are varied along distinguished paths in the moduli space. We find strong evidence supporting the notion that, in the robust setting of quantum Calabi-Yau moduli space, string theory restricts the set of possible Kaehler forms by enforcing ''minimal length'' scales, provided that topology change is properly taken into account. Some lengths, however, may shrink to zero. We also compare stringy geometry to classical general relativity in this context. ((orig.))

  15. Pure spinor formalism as an N = 2 topological string

    International Nuclear Information System (INIS)

    Berkovits, Nathan

    2005-01-01

    Following suggestions of Nekrasov and Siegel, a non-minimal set of fields are added to the pure spinor formalism for the superstring. Twisted c-circumflex = 3 N = 2 generators are then constructed where the pure spinor BRST operator is the fermionic spin-one generator, and the formalism is interpreted as a critical topological string. Three applications of this topological string theory include the super-Poincare covariant computation of multiloop superstring amplitudes without picture-changing operators, the construction of a cubic open superstring field theory without contact-term problems, and a new four-dimensional version of the pure spinor formalism which computes F-terms in the spacetime action

  16. Probing N=2 superconformal field theories with localization

    Energy Technology Data Exchange (ETDEWEB)

    Fiol, Bartomeu [Departament de Física Fonamental i Institut de Ciències del Cosmos,Universitat de Barcelona,Martí i Franquès 1, 08028 Barcelona, Catalonia (Spain); Garolera, Blai [Escuela de Física, Universidad de Costa Rica,11501-2060 San José (Costa Rica); Torrents, Genís [Departament de Física Fonamental i Institut de Ciències del Cosmos,Universitat de Barcelona,Martí i Franquès 1, 08028 Barcelona, Catalonia (Spain)

    2016-01-27

    We use supersymmetric localization to study probes of four dimensional Lagrangian N=2 superconformal field theories. We first derive a unique equation for the eigenvalue density of these theories. We observe that these theories have a Wigner eigenvalue density precisely when they satisfy a necessary condition for having a holographic dual with a sensible higher-derivative expansion. We then compute in the saddle-point approximation the vacuum expectation value of 1/2-BPS circular Wilson loops, and the two-point functions of these Wilson loops with the Lagrangian density and with the stress-energy tensor. This last computation also provides the corresponding Bremsstrahlung functions and entanglement entropies. As expected, whenever a finite fraction of the matter is in the fundamental representation, the results are drastically different from those of N=4 supersymmetric Yang-Mills theory.

  17. Gauge and matter fields coupled to N=2 supergravity

    International Nuclear Information System (INIS)

    Wit, B. de; Lauwers, P.G.; Philippe, R.; Su, S.-Q.; Proeyen, A. van.

    1983-07-01

    The authors consider the potential of a general matter system of N=2 vector and scalar multiplets coupled to supergravity. For lagrangians that are initially quadratic in the matter fields the potential is proved to be either positive or unbounded from below. The results have been obtained in the framework of a superconformal multiplet calculus, and it has been verified that they can be derived from each of the three off-shell representations. As an example the authors consider SO(6) Yang-Mills theory coupled to scalar multiplets in the 10+10 representation, which, for suitably chosen parameters, leads to the potential of gauged N=8 supergravity. Finally, a discussion of the possibility to set residual nonabelian symmetry groups after breaking of N=8 supersymmetry to N=1 or 2 is presented. (Auth.)

  18. Classical and quantum N=2 supersymmetric black holes

    International Nuclear Information System (INIS)

    Behrndt, K.; De Wit, B.; Kallosh, R.; Luest, D.; Mohaupt, T.

    1997-01-01

    We use heterotic/type-II prepotentials to study quantum/classical black holes with half the N=2, D=4 supersymmetries unbroken. We show that, in the case of heterotic string compactifications, the perturbatively corrected entropy formula is given by the tree-level entropy formula with the tree-level coupling constant replaced by the perturbative coupling constant. In the case of type-II compactifications, we display a new entropy/area formula associated with axion-free black-hole solutions, which depends on the electric and magnetic charges as well as on certain topological data of Calabi-Yau three-folds, namely the intersection numbers, the second Chern class and the Euler number of the three-fold. We show that, for both heterotic and type-II theories, there is the possibility to relax the usual requirement of the non-vanishing of some of the charges and still have a finite entropy. (orig.)

  19. Stringy instanton corrections to N=2 gauge couplings

    CERN Document Server

    Billo', Marco; Fucito, Francesco; Lerda, Alberto; Morales, Jose F; Poghosyan, Rubik

    2010-01-01

    We discuss a string model where a conformal four-dimensional N=2 gauge theory receives corrections to its gauge kinetic functions from "stringy" instantons. These contributions are explicitly evaluated by exploiting the localization properties of the integral over the stringy instanton moduli space. The model we consider corresponds to a setup with D7/D3-branes in type I' theory compactified on T4/Z2 x T2, and possesses a perturbatively computable heterotic dual. In the heteoric side the corrections to the quadratic gauge couplings are provided by a 1-loop threshold computation and, under the duality map, match precisely the first few stringy instanton effects in the type I' setup. This agreement represents a very non-trivial test of our approach to the exotic instanton calculus.

  20. Theoretical study of the interaction of N2 with water molecules. (H2O)/sub n/:N2, n = 1--8

    International Nuclear Information System (INIS)

    Curtiss, L.A.; Eisgruber, C.L.

    1984-01-01

    Ab initio molecular orbital calculations including correlation energy have been carried out on the interaction of a single H 2 O molecule with N 2 . The potential energy surface for H 2 O:N 2 is found to have a minimum corresponding to a HOH xxx N 2 structure with a weak ( -1 ) hydrogen bond. A second, less stable, configuration corresponding to a H 2 O xxx N 2 structure with N 2 bonded side on to the oxygen of H 2 O was found to be either a minimum or a saddle point in the potential energy surface depending on the level of calculation. The minimal STO-3G basis set was used to investigate the interaction of up to eight H 2 O molecules with N 2 . Two types of clusters, one containing only HOH xxx N 2 interactions and the other containing both HOH xxxN 2 and H 2 O xxx N 2 interactions, were investigated for [N 2 :(H 2 O)/sub n/, n = 2--8

  1. Green primary explosives: 5-nitrotetrazolato-N2-ferrate hierarchies.

    Science.gov (United States)

    Huynh, My Hang V; Coburn, Michael D; Meyer, Thomas J; Wetzler, Modi

    2006-07-05

    The sensitive explosives used in initiating devices like primers and detonators are called primary explosives. Successful detonations of secondary explosives are accomplished by suitable sources of initiation energy that is transmitted directly from the primaries or through secondary explosive boosters. Reliable initiating mechanisms are available in numerous forms of primers and detonators depending upon the nature of the secondary explosives. The technology of initiation devices used for military and civilian purposes continues to expand owing to variations in initiating method, chemical composition, quantity, sensitivity, explosive performance, and other necessary built-in mechanisms. Although the most widely used primaries contain toxic lead azide and lead styphnate, mixtures of thermally unstable primaries, like diazodinitrophenol and tetracene, or poisonous agents, like antimony sulfide and barium nitrate, are also used. Novel environmentally friendly primary explosives are expanded here to include cat[Fe(II)(NT)(3)(H(2)O)(3)], cat(2)[Fe(II)(NT)(4)(H(2)O)(2)], cat(3)[Fe(II)(NT)(5)(H(2)O)], and cat(4)[Fe(II)(NT)(6)] with cat = cation and NT(-) = 5-nitrotetrazolato-N(2). With available alkaline, alkaline earth, and organic cations as partners, four series of 5-nitrotetrazolato-N(2)-ferrate hierarchies have been prepared that provide a plethora of green primaries with diverse initiating sensitivity and explosive performance. They hold great promise for replacing not only toxic lead primaries but also thermally unstable primaries and poisonous agents. Strategies are also described for the systematic preparation of coordination complex green primaries based on appropriate selection of ligands, metals, and synthetic procedures. These strategies allow for maximum versatility in initiating sensitivity and explosive performance while retaining properties required for green primaries.

  2. HPLC-NMR revisited: Using time-slice HPLC-SPE-NMR with database assisted dereplication

    DEFF Research Database (Denmark)

    Johansen, Kenneth; Wubshet, Sileshi Gizachew; Nyberg, Nils

    2013-01-01

    Time based trapping of chromatographically separated compounds on to solid-phase extraction cartridges (SPE) and subsequent elution to NMR-tubes was done to emulate the function of HPLC–NMR for dereplication purposes. Sufficient mass sensitivity was obtained by the use of a state-of-the-art HPLC......–SPE–NMR-system with a cryogenically cooled probe head, designed for 1.7 mm NMR-tubes. The resulting 1H NMR spectra (600 MHz) were evaluated against a database of previously acquired and prepared spectra. The in-house developed matching algorithm, based on partitioning of the spectra and allowing for changes in the chemical shifts......, is described and the code included as Supplementary Information. Two mixtures of natural products was used to test the approach; one extract of Carthamus oxyacantha (wild safflower) containing an array of spiro compounds and one extract of the endophytic fungus Penicillum namyslowski containing griseofulvin...

  3. NMR techniques in the study of cardiovascular structure and functions

    International Nuclear Information System (INIS)

    Osbakken, M.; Haselgrove, J.

    1987-01-01

    The chapter titles of this book are: Introduction to NMR Techniques;Theory of NMR Probe Design;Overview of Magnetic Resonance Imaging to Study the Cardiovascular System;Vascular Anatomy and Physiology Studied with NMR Techniques;Assessment of Myocardial Ischemia and Infarction by Nuclear Magnetic Resonance Imaging;The Use of MRI in Congenital Heart Disease;Cardiomyopathies and Myocarditis Studied with NMR Techniques;Determination of Myocardial Mechanical Function with Magnetic Resonance Imaging Techniques;Determination of Flow Using NMR Techniques;The Use of Contrast Agents in Cardiac MRI;Can Cardiovascular Disease Be Effectively Evaluated with NMR Spectroscopy? NMR Studies of ATP Synthesis Reactions in the Isolated Heart;Studies of Intermediary Metabolism in the Heart by 13C NMR Spectroscopy;23Na and 39K NMR Spectroscopic Studies of the Intact Beating Heart;and Evaluation of Skeletal Muscle Metabolism in Patients with Congestive Heart Failure Using Phosphorus Nuclear Magnetic Resonance

  4. High resolution NMR spectroscopy of synthetic polymers in bulk

    International Nuclear Information System (INIS)

    Komorski, R.A.

    1986-01-01

    The contents of this book are: Overview of high-resolution NMR of solid polymers; High-resolution NMR of glassy amorphous polymers; Carbon-13 solid-state NMR of semicrystalline polymers; Conformational analysis of polymers of solid-state NMR; High-resolution NMR studies of oriented polymers; High-resolution solid-state NMR of protons in polymers; and Deuterium NMR of solid polymers. This work brings together the various approaches for high-resolution NMR studies of bulk polymers into one volume. Heavy emphasis is, of course, given to 13C NMR studies both above and below Tg. Standard high-power pulse and wide-line techniques are not covered

  5. Technical Note: Simultaneous measurement of sedimentary N2 and N2O production and a modified 15N isotope pairing technique

    Science.gov (United States)

    Hsu, T.-C.; Kao, S.-J.

    2013-12-01

    Dinitrogen (N2) and/or nitrous oxide (N2O) are produced through denitrification, anaerobic ammonium oxidation (anammox) or nitrification in sediments, of which entangled processes complicate the absolute rate estimations of gaseous nitrogen production from individual pathways. The classical isotope pairing technique (IPT), the most common 15N nitrate enrichment method to quantify denitrification, has recently been modified by different researchers to (1) discriminate between the N2 produced by denitrification and anammox or to (2) provide a more accurate denitrification rate under considering production of both N2O and N2. In case 1, the revised IPT focused on N2 production being suitable for the environments of a low N2O-to-N2 production ratio, while in case 2, anammox was neglected. This paper develops a modified method to refine previous versions of IPT. Cryogenic traps were installed to separately preconcentrate N2 and N2O, thus allowing for subsequent measurement of the two gases generated in one sample vial. The precision is better than 2% for N2 (m/z 28, m/z 29 and m/z 30), and 1.5% for N2O (m/z 44, m/z 45 and m/z 46). Based on the six m/z peaks of the two gases, the 15N nitrate traceable processes including N2 and N2O from denitrification and N2 from anammox were estimated. Meanwhile, N2O produced by nitrification was estimated via the production rate of unlabeled 44N2O. To validate the applicability of our modified method, incubation experiments were conducted using sediment cores taken from the Danshuei Estuary in Taiwan. Rates of the aforementioned nitrogen removal processes were successfully determined. Moreover, N2O yield was as high as 66%, which would significantly bias previous IPT approaches if N2O was not considered. Our modified method not only complements previous versions of IPT but also provides more comprehensive information to advance our understanding of nitrogen dynamics of the water-sediment interface.

  6. Nuclear magnetic resonance (NMR): principles and applications

    International Nuclear Information System (INIS)

    Quibilan, E.I.

    The basis for the phenomenon of nuclear magnetic resonance (NMR) is the ability of certain nuclei possessing both intrinsic angular momentum or ''spin'' I and magnetic moment to absorb electromagnetic energy in the radio frequency range. In principle, there are approximately 200 nuclei which may be investigated using the NMR technique. The NMR spectrum consists of intensity peaks along an axis calibrated in terms of the steady magnetic field or the frequency of the radiofrequency electromagnetic radiation. Analysis of the number, spacing, position and intensity of the lines in an NMR spectrum consists of intensity peaks along an axis calibrated in terms of the steady magnetic field or the frequency of the radiofrequency electromagnetic radiation. Analysis of the number, spacing, position and intensity of the lines in an NMR spectrum provides a variety of qualitative and quantitative analytical applications. The most obvious applications consist of the measurements of nuclear properties, such as spin number and nuclear magnetic moment. In liquids, the fine structure of resonance spectra provides a tool for chemical identification and molecular structure analysis. Other applications include the measurements of self-diffusion coefficients, magnetic fields and field homogeneity, inter-nuclear distances, and, in some cases, the water content of biological materials. (author)

  7. N = 2 local and N = 4 non-local reductions of supersymmetric KP hierarchy in N = 2 superspace

    International Nuclear Information System (INIS)

    Delduc, F.; Gallot, L.; Sorin, A.

    1999-01-01

    An N = 4 supersymmetric matrix KP hierarchy is proposed and a wide class of its reductions which are characterized by a finite number of fields are described. This class includes the one-dimensional reduction of the two-dimensional N = (2,2) superconformal Toda lattice hierarchy possessing the N = 4 supersymmetry -- the N = 4 Toda chain hierarchy - which may be relevant in the construction of supersymmetric matrix models. The Lax-pair representations of the bosonic and fermionic flows, corresponding local and non-local Hamiltonians, finite and infinite discrete symmetries, the first two Hamiltonian structures and the recursion operator connecting all evolution equations and the Hamiltonian structures of the N = 4 Toda chain hierarchy are constructed in explicit form. Is secondary reduction to the N 4 supersymmetric α = - 2 KdV hierarchy is

  8. Comparative pathology of pigs infected with Korean H1N1, H1N2, or H3N2 swine influenza A viruses.

    Science.gov (United States)

    Lyoo, Kwang-Soo; Kim, Jeong-Ki; Jung, Kwonil; Kang, Bo-Kyu; Song, Daesub

    2014-09-24

    The predominant subtypes of swine influenza A virus (SIV) in Korea swine population are H1N1, H1N2, and H3N2. The viruses are genetically close to the classical U.S. H1N1 and triple-reassortant H1N2 and H3N2 viruses, respectively. Comparative pathogenesis caused by Korean H1N1, H1N2, and H3N2 SIV was evaluated in this study. The H3N2 infected pigs had severe scores of gross and histopathological lesions at post-inoculation days (PID) 2, and this then progressively decreased. Both the H1N1 and H1N2 infected pigs lacked gross lesions at PID 2, but they showed moderate to severe pneumonia on PID 4, 7 and 14. The pigs infected with H1N1 had significant scores of gross and histopathological lesions when compared with the other pigs infected with H1N2, H3N2, and mock at PID 14. Mean SIV antigen-positive scores were rarely detected for pigs infected with H1N2 and H3N2 from PID 7, whereas a significantly increased amount of viral antigens were found in the bronchioles and alveolar epithelium of the H1N1infected pigs at PID 14. We demonstrated that Korean SIV subtypes had different pulmonary pathologic patterns. The Korean H3N2 rapidly induced acute lung lesions such as broncho-interstitial pneumonia, while the Korean H1N1 showed longer course of infection as compared to other strains.

  9. Potential short-term losses of N2O and N2 from high concentrations of biogas digestate in arable soils

    Science.gov (United States)

    Fiedler, Sebastian Rainer; Augustin, Jürgen; Wrage-Mönnig, Nicole; Jurasinski, Gerald; Gusovius, Bertram; Glatzel, Stephan

    2017-09-01

    Biogas digestate (BD) is increasingly used as organic fertilizer, but has a high potential for NH3 losses. Its proposed injection into soils as a countermeasure has been suggested to promote the generation of N2O, leading to a potential trade-off. Furthermore, the effect of high nutrient concentrations on N2 losses as they may appear after injection of BD into soil has not yet been evaluated. Hence, we performed an incubation experiment with soil cores in a helium-oxygen atmosphere to examine the influence of soil substrate (loamy sand, clayey silt), water-filled pore space (WFPS; 35, 55, 75 %) and application rate (0, 17.6 and 35.2 mL BD per soil core, 250 cm3) on the emission of N2O, N2 and CO2 after the usage of high loads of BD. To determine the potential capacity for gaseous losses, we applied anaerobic conditions by purging with helium for the last 24 h of incubation. Immediate N2O and N2 emissions as well as the N2 / (N2O+N2) product ratio depended on soil type and increased with WFPS, indicating a crucial role of soil gas diffusivity for the formation and emission of nitrogenous gases in agricultural soils. However, emissions did not increase with the application rate of BD. This is probably due to an inhibitory effect of the high NH4+ content of BD on nitrification. Our results suggest a larger potential for N2O formation immediately following BD injection in the fine-textured clayey silt compared to the coarse loamy sand. By contrast, the loamy sand showed a higher potential for N2 production under anaerobic conditions. Our results suggest that short-term N losses of N2O and N2 after injection may be higher than probable losses of NH3 following surface application of BD.

  10. NMR Phase Noise in Bitter Magnets

    Science.gov (United States)

    Sigmund, E. E.; Calder, E. S.; Thomas, G. W.; Mitrović, V. F.; Bachman, H. N.; Halperin, W. P.; Kuhns, P. L.; Reyes, A. P.

    2001-02-01

    We have studied the temporal instability of a high field resistive Bitter magnet through nuclear magnetic resonance (NMR). This instability leads to transverse spin decoherence in repeated and accumulated NMR experiments as is normally performed during signal averaging. We demonstrate this effect via Hahn echo and Carr-Purcell-Meiboom-Gill (CPMG) transverse relaxation experiments in a 23-T resistive magnet. Quantitative analysis was found to be consistent with separate measurements of the magnetic field frequency fluctuation spectrum, as well as with independent NMR experiments performed in a magnetic field with a controlled instability. Finally, the CPMG sequence with short pulse delays is shown to be successful in recovering the intrinsic spin-spin relaxation even in the presence of magnetic field temporal instability.

  11. Remote tuning of NMR probe circuits.

    Science.gov (United States)

    Kodibagkar, V D; Conradi, M S

    2000-05-01

    There are many circumstances in which the probe tuning adjustments cannot be located near the rf NMR coil. These may occur in high-temperature NMR, low-temperature NMR, and in the use of magnets with small diameter access bores. We address here circuitry for connecting a fixed-tuned probe circuit by a transmission line to a remotely located tuning network. In particular, the bandwidth over which the probe may be remotely tuned while keeping the losses in the transmission line acceptably low is considered. The results show that for all resonant circuit geometries (series, parallel, series-parallel), overcoupling of the line to the tuned circuit is key to obtaining a large tuning bandwidth. At equivalent extents of overcoupling, all resonant circuit geometries have nearly equal remote tuning bandwidths. Particularly for the case of low-loss transmission line, the tuning bandwidth can be many times the tuned circuit's bandwidth, f(o)/Q. Copyright 2000 Academic Press.

  12. Deuterium NMR, induced and intrinsic cholesteric lyomesophases

    International Nuclear Information System (INIS)

    Alcantara, M.R.

    1982-01-01

    Induced and intrinsic cholesteric lyotropic mesophases were studied. Induced cholesteric lyomesophases based on potassium laurate (KL) system, with small amounts of cholesterol added, were studied by deuterium NMR and by polarizing microscopy. Order profiles obtained from deuterium NMR of KL perdenderated chains in both induced cholesteric and normal mesophases were compared. The intrinsic cholesteric lyotropic mesophases were based on the amphiphile potassium N-lauroyl serinate (KLNS) in the resolved levo form. The study of the type I intrinsic cholesteric mesophase was made by optical microscopy under polarized light and the type II intrinsic cholesteric lyomesophase was characterized by deuterium NMR. The new texture was explained by the use of the theory of disclinations developed for thermotropic liquid crystals, specially for cholesteric type. (M.J.C.) [pt

  13. Determination of solid fat content by NMR

    International Nuclear Information System (INIS)

    Kawada, Tsukasa; Kato, Chihiro; Suzuki, Kazuaki

    1984-01-01

    To establish a standard method for determing solid fat content, the NMR method was tested at six laboratories and the results were examined for collaboration. Two types of instruments, pulse NMR and wide-line NMR were used. Standard deviation in results at six laboratories was less than 1.5 for the step wise method, but more than 1.5 for the rapid method. The standard deviation in results at a single laboratory was much less than either of these cases. No significant difference could be observed in the values obtained using both instruments. Solid fat content values measured for a mixture of fully hydrogenated rapeseed and rapeseed oil agreed well with the percentage of solid by weight. (author)

  14. Muscular pathology: echographic and NMR imaging aspects

    International Nuclear Information System (INIS)

    Pascal-Suisse, P.; Beaurain, P.; Mougniot, C.

    1995-01-01

    A comparison of echographic techniques and NMR imaging has been done for the diagnosis of muscular trauma and tumor pathologies. In traumatic pathology, the echographic analysis allows to determine the complete assessment of recent muscular injuries. NMR imaging can be used in granuloma or fibrous callosity appreciation and for the analysis of deep injury (muscles and muscles-tendon junctions) and of muscular aponeurosis. Echography must be used together with color coding Doppler technique in the diagnosis of tumor pathology and for the study of slow fluxes. The recently available energy Doppler technique seems to be powerful in the study of vascularization of small expansive formations, but their extension to adjacent bone or tissue can only be appreciated using NMR imaging. (J.S.)

  15. Contact replacement for NMR resonance assignment.

    Science.gov (United States)

    Xiong, Fei; Pandurangan, Gopal; Bailey-Kellogg, Chris

    2008-07-01

    Complementing its traditional role in structural studies of proteins, nuclear magnetic resonance (NMR) spectroscopy is playing an increasingly important role in functional studies. NMR dynamics experiments characterize motions involved in target recognition, ligand binding, etc., while NMR chemical shift perturbation experiments identify and localize protein-protein and protein-ligand interactions. The key bottleneck in these studies is to determine the backbone resonance assignment, which allows spectral peaks to be mapped to specific atoms. This article develops a novel approach to address that bottleneck, exploiting an available X-ray structure or homology model to assign the entire backbone from a set of relatively fast and cheap NMR experiments. We formulate contact replacement for resonance assignment as the problem of computing correspondences between a contact graph representing the structure and an NMR graph representing the data; the NMR graph is a significantly corrupted, ambiguous version of the contact graph. We first show that by combining connectivity and amino acid type information, and exploiting the random structure of the noise, one can provably determine unique correspondences in polynomial time with high probability, even in the presence of significant noise (a constant number of noisy edges per vertex). We then detail an efficient randomized algorithm and show that, over a variety of experimental and synthetic datasets, it is robust to typical levels of structural variation (1-2 AA), noise (250-600%) and missings (10-40%). Our algorithm achieves very good overall assignment accuracy, above 80% in alpha-helices, 70% in beta-sheets and 60% in loop regions. Our contact replacement algorithm is implemented in platform-independent Python code. The software can be freely obtained for academic use by request from the authors.

  16. Prediction of peak overlap in NMR spectra

    International Nuclear Information System (INIS)

    Hefke, Frederik; Schmucki, Roland; Güntert, Peter

    2013-01-01

    Peak overlap is one of the major factors complicating the analysis of biomolecular NMR spectra. We present a general method for predicting the extent of peak overlap in multidimensional NMR spectra and its validation using both, experimental data sets and Monte Carlo simulation. The method is based on knowledge of the magnetization transfer pathways of the NMR experiments and chemical shift statistics from the Biological Magnetic Resonance Data Bank. Assuming a normal distribution with characteristic mean value and standard deviation for the chemical shift of each observable atom, an analytic expression was derived for the expected overlap probability of the cross peaks. The analytical approach was verified to agree with the average peak overlap in a large number of individual peak lists simulated using the same chemical shift statistics. The method was applied to eight proteins, including an intrinsically disordered one, for which the prediction results could be compared with the actual overlap based on the experimentally measured chemical shifts. The extent of overlap predicted using only statistical chemical shift information was in good agreement with the overlap that was observed when the measured shifts were used in the virtual spectrum, except for the intrinsically disordered protein. Since the spectral complexity of a protein NMR spectrum is a crucial factor for protein structure determination, analytical overlap prediction can be used to identify potentially difficult proteins before conducting NMR experiments. Overlap predictions can be tailored to particular classes of proteins by preparing statistics from corresponding protein databases. The method is also suitable for optimizing recording parameters and labeling schemes for NMR experiments and improving the reliability of automated spectra analysis and protein structure determination.

  17. Extreme emission of N2O from tropical wetland soil (Pantanal, South America)

    DEFF Research Database (Denmark)

    Jensen, Lars Liengård; Nielsen, Lars Peter; Revsbech, Niels Peter

    2013-01-01

    Nitrous oxide (N(2)O) is an important greenhouse gas and ozone depleter, but the global budget of N(2)O remains unbalanced. Currently, ~25% of the global N(2)O emission is ascribed to uncultivated tropical soils, but the exact locations and controlling mechanisms are not clear. Here we present...... the first study of soil N(2)O emission from the Pantanal indicating that this South American wetland may be a significant natural source of N(2)O. At three sites, we repeatedly measured in situ fluxes of N(2)O and sampled porewater nitrate [Formula: see text] during the low water season in 2008 and 2009....... In 2010, 10 sites were screened for in situ fluxes of N(2)O and soil [Formula: see text] content. The in situ fluxes of N(2)O were comparable to fluxes from heavily fertilized forests or agricultural soils. An important parameter affecting N(2)O emission rate was precipitation, inducing peak emissions...

  18. Applications of NMR spectroscopy to xenobiotic metabolism

    International Nuclear Information System (INIS)

    Harris, T.M.

    1989-01-01

    Recent years have seen high field NMR spectrometers become commonplace in research laboratories. At the same time, major advances in methodology for structural analysis have occurred, particularly notable among these being the development of two-dimensional spectroscopic techniques. Many applications have been made of NMR spectroscopy in the study of xenobiotic metabolic processes. This deals with two specific applications which have been made in the author's laboratory and involve mechanistic studies of the reactions of the carcinogens ethylene dibromide and aflatoxin with DNA

  19. Tritiation methods and tritium NMR spectroscopy

    International Nuclear Information System (INIS)

    Jaiswal, D.K.; Morimoto, H.; Salijoughian, M.; Williams, P.G.

    1991-09-01

    We have used a simple process for the production of highly tritiated water and characterized the product species by 1 H and 3 H NMR spectroscopy. The water is readily manipulated and used in subsequent reactions either as T 2 O, CH 3 COOT or CF 3 COOT. Development of tritiated diimide has progressed to the point where cis-hydrogenated products at 1-20 Ci/mmole S.A. are possible. Tri-n-butyl tin tritide has been produced at >95% tritium content and well characterized by multinuclear NMR techniques. 27 refs., 3 figs

  20. Applications of NMR in biological metabolic research

    International Nuclear Information System (INIS)

    Nie Jiarui; Li Xiuqin; He Chunjian

    1989-01-01

    The nuclear magnetic resonance has become a powerful means of studying biological metabolism in non-invasive and non-destructive way. Being used to study the metabolic processes of living system in normal physiological conditions as well as in molecular level, the method is better than other conventional approaches. Using important parameters such as NMR-chemical shifts, longitudinal relaxation time and transverse relaxation time, it is possible to probe the metabolic processes as well as conformation, concentration, transportation and distribution of reacting and resulting substances. The NMR spectroscopy of 1 H, 31 P and 13 C nuclei has already been widely used in metabolic researches

  1. Deuteron NMR and modelling in solid polymers

    International Nuclear Information System (INIS)

    Hirschinger, J.

    1992-01-01

    Deuteron NMR techniques are described and some recent applications to the study of rotational motions in solid polymers are reviewed. The information content and the domain of applicability of each technique are presented. Ultra-slow motions are studied in real time without any motional model consideration. For very fast motions, computer molecular dynamics simulations are shown to complement the NMR results. Experimental examples deal with the chain motion in the crystalline α-phase of poly(vinylidenefluoride) and nylon 6,6

  2. Programmable pulse series generator for NMR relaxometer

    International Nuclear Information System (INIS)

    Stolbunov, R.N.; Chichikov, S.A.; Lundin, A.G.

    2005-01-01

    Paper describes a pulse series generator for NMR relaxometer. The operation mode is set on the basis of the PC program by the PCI bus in the internal memory. The design is based on two Altera Company MAX7000S and Cyclone family microcircuits using the Qartus II 4.0 software. The basic parameters are as follows: pulse minimum length - 50 ns, time resolution - 10 ns, pulse maximum number - 1024, number of controlled output channels - 8. The designed device as a part of the NMR hardware-software system enables to record, to process and to store the experiment results in the form of electronic document [ru

  3. NMR relaxation times of natural rubber latex

    International Nuclear Information System (INIS)

    Harun, S.; Aziz, H.; Basir, Z.

    1994-01-01

    NMR relaxation times T sub 1 and T sub 2 of natural rubber latex have been measured at 25 degree C on a pulsed NMR spectrometer. The work focuses on the variation of the relaxation times with the amount of water content from 0% to 50%. The water content was adjusted by centrifuging and removing a certain amount of water from the sample. The data were analysed using a biexponential fitting procedure which yields simultaneously either T sub 1a and T sub 1b or T sub 2a and T sub 2b. The amount of solid was compared with the known amount of dry rubber content

  4. Pure N=2 super Yang-Mills and exact WKB

    International Nuclear Information System (INIS)

    Kashani-Poor, Amir-Kian; Troost, Jan

    2015-01-01

    We apply exact WKB methods to the study of the partition function of pure N=2ϵ i -deformed gauge theory in four dimensions in the context of the 2d/4d correspondence. We study the partition function at leading order in ϵ 2 /ϵ 1 (i.e. at large central charge) and in an expansion in ϵ 1 . We find corrections of the form ∼exp [−((/tiny SW periods)/(ϵ 1 ))] to this expansion. We attribute these to the exchange of the order of summation over gauge instanton number and over powers of ϵ 1 when passing from the Nekrasov form of the partition function to the topological string theory inspired form. We conjecture that such corrections should be computable from a worldsheet perspective on the partition function. Our results follow upon the determination of the Stokes graphs associated to the Mathieu equation with complex parameters and the application of exact WKB techniques to compute the Mathieu characteristic exponent.

  5. Summing up D-instantons in N=2 supergravity

    International Nuclear Information System (INIS)

    Ketov, Sergei V.

    2003-01-01

    The non-perturbative quantum geometry of the universal hypermultiplet (UH) is investigated in N=2 supergravity. The UH low-energy effective action is given by the four-dimensional quaternionic non-linear sigma-model having an U(1)xU(1) isometry. The UH metric is governed by the single real pre-potential that is an eigenfunction of the Laplacian in the hyperbolic plane. We calculate the classical pre-potential corresponding to the standard (Ferrara-Sabharwal) metric of the UH arising in the Calabi-Yau compactification of type-II superstrings. The non-perturbative quaternionic metric, describing the D-instanton contributions to the UH geometry, is found by requiring the SL(2,Z) modular invariance of the UH pre-potential. The pre-potential found is unique, while it coincides with the D-instanton function of Green and Gutperle, given by the order-3/2 Eisenstein series. As a by-product, we prove cluster decomposition of D-instantons in curved spacetime. The non-perturbative UH pre-potential interpolates between the perturbative (large CY volume) region and the superconformal (Landau-Ginzburg) region in the UH moduli space. We also calculate a non-perturbative scalar potential in the hyper-Kaehler limit, when an abelian isometry of the UH metric is gauged in the presence of D-instantons

  6. Novel Lipid Biomarkers for Past Oceanic N2 Fixation

    Science.gov (United States)

    Bale, N. J.; Hopmans, E. C.; Villareal, T. A.; Zell, C. I.; Sinninghe Damsté, , J.; Schouten, S.

    2014-12-01

    Nitrogen-fixing cyanobacteria play important roles in the biogeochemical cycles of aquatic systems. Both heterocystous and non-heterocystous N2-fixing cyanobacteria are symbiotic with marine diatoms and thrive in low nutrient environments. These associations are significant exporters of carbon to the deep-sea, but suitable tracers for reconstructing their importance in past environments are lacking. We recently analyzed the heterocyst glycolipids (HGs) of the heterocystous Richelia intracellularis symbiont of the marine diatoms Hemiaulus hauckii and H. membranaceus and found unique C5 glycolipids with C30-32 carbon chains, a structure different from the C6 glycolipids detected in freshwater heterocystous cyanobacteria. We developed a high performance liquid chromatography/ multiple reaction monitoring mass spectrometry (HPLC/MS) method specific for trace analysis of long chain C5 HGs and applied it to suspended particulate matter (SPM) and surface sediment from the Amazon plume, a region known to harbor marine diatoms carrying heterocystous cyanobacteria as endosymbionts. C5 HGs were detected in both SPM and sediments demonstrating their biomarker potential. They were not detected in SPM or sediment from freshwater settings in the region. Rather, limnetic SPM and sediments contained C6 HGs which are established biomarkers for free-living heterocystous cyanobacteria. Glycolipids have been found preserved in sediments of up to 49 Ma old. Our development of the C5 biomarkers has the potential to improve our knowledge of the contribution of symbiotic cyanobacteria to the paleo-N-cycle.

  7. Split Attractor Flow in N=2 Minimally Coupled Supergravity

    CERN Document Server

    Ferrara, Sergio; Orazi, Emanuele

    2011-01-01

    We classify the stability region, marginal stability walls (MS) and split attractor flows for two-center extremal black holes in four-dimensional N=2 supergravity minimally coupled to n vector multiplets. It is found that two-center (continuous) charge orbits, classified by four duality invariants, either support a stability region ending on a MS wall or on an anti-marginal stability (AMS) wall, but not both. Therefore, the scalar manifold never contains both walls. Moreover, the BPS mass of the black hole composite (in its stability region) never vanishes in the scalar manifold. For these reasons, the "bound state transformation walls" phenomenon does not necessarily occur in these theories. The entropy of the flow trees also satisfies an inequality which forbids "entropy enigma" decays in these models. Finally, the non-BPS case, due to the existence of a "fake" superpotential satisfying a triangle inequality, can be treated as well, and it can be shown to exhibit a split attractor flow dynamics which, at le...

  8. Summing up D-instantons in N=2 supergravity

    Energy Technology Data Exchange (ETDEWEB)

    Ketov, Sergei V. E-mail: ketov@phys.metro-u.ac.jp

    2003-01-20

    The non-perturbative quantum geometry of the universal hypermultiplet (UH) is investigated in N=2 supergravity. The UH low-energy effective action is given by the four-dimensional quaternionic non-linear sigma-model having an U(1)xU(1) isometry. The UH metric is governed by the single real pre-potential that is an eigenfunction of the Laplacian in the hyperbolic plane. We calculate the classical pre-potential corresponding to the standard (Ferrara-Sabharwal) metric of the UH arising in the Calabi-Yau compactification of type-II superstrings. The non-perturbative quaternionic metric, describing the D-instanton contributions to the UH geometry, is found by requiring the SL(2,Z) modular invariance of the UH pre-potential. The pre-potential found is unique, while it coincides with the D-instanton function of Green and Gutperle, given by the order-3/2 Eisenstein series. As a by-product, we prove cluster decomposition of D-instantons in curved spacetime. The non-perturbative UH pre-potential interpolates between the perturbative (large CY volume) region and the superconformal (Landau-Ginzburg) region in the UH moduli space. We also calculate a non-perturbative scalar potential in the hyper-Kaehler limit, when an abelian isometry of the UH metric is gauged in the presence of D-instantons.

  9. Analysis of (n, 2n) multiplication in lead

    International Nuclear Information System (INIS)

    Segev, M.

    1984-01-01

    Lead is being considered as a possible amplifier of neutrons for fusion blankets. A simple one-group model of neutron multiplications in Pb is presented. Given the 14 MeV neutron cross section on Pb, the model predicts the multiplication. Given measured multiplications, the model enables the determination of the (n, 2n) and transport cross sections. Required for the model are: P-the collision probability for source neutrons in the Pb body-and W- an average collision probability for non-virgin, non-degraded neutrons. In simple geometries, such as a source in the center of a spherical shell, P and an approximate W can be expressed analytically in terms of shell dimensions and the Pb transport cross section. The model was applied to Takahashi's measured multiplications in Pb shells in order to understand the apparent very high multiplicative power of Pb. The results of the analysis are not consistent with basic energy-balance and cross section magnitude constraints in neutron interaction theory. (author)

  10. Testing the Role of Recollision in N2+ Air Lasing

    Science.gov (United States)

    Britton, Mathew; Laferrière, Patrick; Ko, Dong Hyuk; Li, Zhengyan; Kong, Fanqi; Brown, Graham; Naumov, Andrei; Zhang, Chunmei; Arissian, Ladan; Corkum, P. B.

    2018-03-01

    It has been known for many years that during filamentation of femtosecond light pulses in air, gain is observed on the B to X transition in N2+ . While the gain mechanism remains unclear, it has been proposed that recollision, a process that is fundamental to much of strong field science, is critical for establishing gain. We probe this hypothesis by directly comparing the influence of the ellipticity of the pump light on gain in air filaments. Then, we decouple filamentation from gain by measuring the gain in a thin gas jet that we also use for high harmonic generation. The latter allows us to compare the dependence of the gain on the ellipticity of the pump with the dependence of the high harmonic signal on the ellipticity of the fundamental. We find that gain and harmonic generation have very different behavior in both filaments and in the jet. In fact, in a jet we even measure gain with circular polarization. Thus, we establish that recollision does not play a significant role in creating the inversion.

  11. Effects of flooding-induced N2O production, consumption and emission dynamics on the annual N2O emission budget in wetland soil

    DEFF Research Database (Denmark)

    Jørgensen, Christian Juncher; Elberling, Bo

    2012-01-01

    during mid-summer when the WL was at its seasonally lowest counterbalancing ~6.4% of the total annual net N2O emission budget. Main surface emission periods of N2O were observed when the water level and associated peaks in subsurface N2O concentrations were gradually decreasing to soil depths down to 40...... production and consumption capacities where >500 nmol N2O cm-3 were sequentially produced and consumed in less than 24 hrs. It is concluded that a higher future frequency of flooding induced N2O emissions will have a very limited effect on the net annual N2O emission budget as long as NO3- availability...

  12. DETECTING AND CONSTRAINING N2 ABUNDANCES IN PLANETARY ATMOSPHERES USING COLLISIONAL PAIRS

    International Nuclear Information System (INIS)

    Schwieterman, Edward W.; Meadows, Victoria S.; Misra, Amit; Robinson, Tyler D.; Domagal-Goldman, Shawn

    2015-01-01

    Characterizing the bulk atmosphere of a terrestrial planet is important for determining surface pressure and potential habitability. Molecular nitrogen (N 2 ) constitutes the largest fraction of Earth's atmosphere and is likely to be a major constituent of many terrestrial exoplanet atmospheres. Due to its lack of significant absorption features, N 2 is extremely difficult to remotely detect. However, N 2 produces an N 2N 2 collisional pair, (N 2 ) 2 , which is spectrally active. Here we report the detection of (N 2 ) 2 in Earth's disk-integrated spectrum. By comparing spectra from NASA's EPOXI mission to synthetic spectra from the NASA Astrobiology Institute's Virtual Planetary Laboratory three-dimensional spectral Earth model, we find that (N 2 ) 2 absorption produces a ∼35% decrease in flux at 4.15 μm. Quantifying N 2 could provide a means of determining bulk atmospheric composition for terrestrial exoplanets and could rule out abiotic O 2 generation, which is possible in rarefied atmospheres. To explore the potential effects of (N 2 ) 2 in exoplanet spectra, we used radiative transfer models to generate synthetic emission and transit transmission spectra of self-consistent N 2 –CO 2 –H 2 O atmospheres, and analytic N 2 –H 2 and N 2 –H 2 –CO 2 atmospheres. We show that (N 2 ) 2 absorption in the wings of the 4.3 μm CO 2 band is strongly dependent on N 2 partial pressures above 0.5 bar and can significantly widen this band in thick N 2 atmospheres. The (N 2 ) 2 transit transmission signal is up to 10 ppm for an Earth-size planet with an N 2 -dominated atmosphere orbiting within the habitable zone of an M5V star and could be substantially larger for planets with significant H 2 mixing ratios

  13. Seroprevalence of H1N1, H3N2 and H1N2 influenza viruses in pigs in seven European countries in 2002-2003.

    Science.gov (United States)

    Van Reeth, Kristien; Brown, Ian H; Dürrwald, Ralf; Foni, Emanuela; Labarque, Geoffrey; Lenihan, Patrick; Maldonado, Jaime; Markowska-Daniel, Iwona; Pensaert, Maurice; Pospisil, Zdenek; Koch, Guus

    2008-05-01

    Avian-like H1N1 and human-like H3N2 swine influenza viruses (SIV) have been considered widespread among pigs in Western Europe since the 1980s, and a novel H1N2 reassortant with a human-like H1 emerged in the mid 1990s. This study, which was part of the EC-funded 'European Surveillance Network for Influenza in Pigs 1', aimed to determine the seroprevalence of the H1N2 virus in different European regions and to compare the relative prevalences of each SIV between regions. Laboratories from Belgium, the Czech Republic, Germany, Italy, Ireland, Poland and Spain participated in an international serosurvey. A total of 4190 sow sera from 651 farms were collected in 2002-2003 and examined in haemagglutination inhibition tests against H1N1, H3N2 and H1N2. In Belgium, Germany, Italy and Spain seroprevalence rates to each of the three SIV subtypes were high (> or =30% of the sows seropositive) to very high (> or =50%), except for a lower H1N2 seroprevalence rate in Italy (13.8%). Most sows in these countries with high pig populations had antibodies to two or three subtypes. In Ireland, the Czech Republic and Poland, where swine farming is less intensive, H1N1 was the dominant subtype (8.0-11.7% seropositives) and H1N2 and H3N2 antibodies were rare (0-4.2% seropositives). Thus, SIV of H1N1, H3N2 and H1N2 subtype are enzootic in swine producing regions of Western Europe. In Central Europe, SIV activity is low and the circulation of H3N2 and H1N2 remains to be confirmed. The evolution and epidemiology of SIV throughout Europe is being further monitored through a second 'European Surveillance Network for Influenza in Pigs'.

  14. N=2 super - W{sub 3}{sup (2)} algebra in superfields

    Energy Technology Data Exchange (ETDEWEB)

    Krivonos, S; Sorin, A [Joint Inst. for Nuclear Research, Dubna (Russian Federation). Lab. of Theoretical Physics; [Istituto Nazionale di Fisica Nucleare, Frascati (Italy); Ivanov, E [Joint Inst. for Nuclear Research, Dubna (Russian Federation). Lab. of Theoretical Physics

    1995-05-01

    It is presented a manifestly N=2 supersymmetric formulation of N=2 super-W{sub 3}{sup (2)} algebra (its classical version) in terms of the spin 1 unconstrained generating a N=2 superconformal subalgebra and the spins 1/2, 2 fermionic constrained supercurrents. It is considered a superfield reduction of N=2 super-W{sub 3}{sup (2)} to N=2 super-W{sub 3} and construct a family of evolution equations for which N=2 super-W{sub 3}{sup (2)} provides the second Hamiltonian structure.

  15. Investigation of N2O Production from 266 and 532 nm Laser Flash Photolysis of O3/N2/O2 Mixtures

    Science.gov (United States)

    Estupinan, E. G.; Nicovich, J. M.; Li, J.; Cunnold, D. M.; Wine, P. H.

    2002-01-01

    Tunable diode laser absorption spectroscopy has been employed to measure the amount of N2O produced from laser flash photolysis of O3/N2/O2 mixtures at 266 and 532 nm. In the 532 nm photolysis experiments very little N2O is observed, thus allowing an upper limit yield of 7 x 10(exp -8) to be established for the process O3 + N2 yield N2O + O2, where O3 is nascent O3 that is newly formed via O(3P(sub J)) + O2 recombination (with vibrational excitation near the dissociation energy of O3). The measured upper limit yield is a factor of approx. 600 smaller than a previous literature value and is approximately a factor of 10 below the threshold for atmospheric importance. In the 266 nm photolysis experiments, significant N2O production is observed and the N2O quantum yield is found to increase linearly with pressure over the range 100 - 900 Torr in air bath gas. The source of N2O in the 266 nm photolysis experiments is believed to be the addition reaction O(1D(sub 2)) + N2 + M yields (k(sub sigma)) N2O + M, although reaction of (very short-lived) electronically excited O3 with N2 cannot be ruled out by the available data. Assuming that all observed N2O comes from the O(1D(sub 2)) + N2 + M reaction, the following expression describes the temperature dependence of k(sub sigma) (in its third-order low-pressure limit) that is consistent with the N2O yield data: k(sub sigma) = (2.8 +/- 0.1) x 10(exp -36)(T/300)(sup -(0-88+0.36)) cm(sup 6) molecule(sup -2)/s, where the uncertainties are 2(sigma) and represent precision only. The accuracy of the reported rate coefficients at the 95% confidence level is estimated to be 30 - 40% depending on the temperature. Model calculations suggest that gas phase processes initiated by ozone absorption of a UV photon represent about 1.4% of the currently estimated global source strength of atmospheric N2O. However, these processes could account for a significant fraction of the oxygen mass-independent enrichment observed in atmospheric N2O, and

  16. Recommendations of the wwPDB NMR Validation Task Force

    Science.gov (United States)

    Montelione, Gaetano T.; Nilges, Michael; Bax, Ad; Güntert, Peter; Herrmann, Torsten; Richardson, Jane S.; Schwieters, Charles; Vranken, Wim F.; Vuister, Geerten W.; Wishart, David S.; Berman, Helen M.; Kleywegt, Gerard J.; Markley, John L.

    2013-01-01

    As methods for analysis of biomolecular structure and dynamics using nuclear magnetic resonance spectroscopy (NMR) continue to advance, the resulting 3D structures, chemical shifts, and other NMR data are broadly impacting biology, chemistry, and medicine. Structure model assessment is a critical area of NMR methods development, and is an essential component of the process of making these structures accessible and useful to the wider scientific community. For these reasons, the Worldwide Protein Data Bank (wwPDB) has convened an NMR Validation Task Force (NMR-VTF) to work with the wwPDB partners in developing metrics and policies for biomolecular NMR data harvesting, structure representation, and structure quality assessment. This paper summarizes the recommendations of the NMR-VTF, and lays the groundwork for future work in developing standards and metrics for biomolecular NMR structure quality assessment. PMID:24010715

  17. Structural properties of carbon nanotubes derived from 13C NMR

    KAUST Repository

    Abou-Hamad, E.; Babaa, M.-R.; Bouhrara, M.; Kim, Y.; Saih, Y.; Dennler, S.; Mauri, F.; Basset, Jean-Marie; Goze-Bac, C.; Wå gberg, T.

    2011-01-01

    We present a detailed experimental and theoretical study on how structural properties of carbon nanotubes can be derived from 13C NMR investigations. Magic angle spinning solid state NMR experiments have been performed on single- and multiwalled

  18. nmrML: A Community Supported Open Data Standard for the Description, Storage, and Exchange of NMR Data.

    Science.gov (United States)

    Schober, Daniel; Jacob, Daniel; Wilson, Michael; Cruz, Joseph A; Marcu, Ana; Grant, Jason R; Moing, Annick; Deborde, Catherine; de Figueiredo, Luis F; Haug, Kenneth; Rocca-Serra, Philippe; Easton, John; Ebbels, Timothy M D; Hao, Jie; Ludwig, Christian; Günther, Ulrich L; Rosato, Antonio; Klein, Matthias S; Lewis, Ian A; Luchinat, Claudio; Jones, Andrew R; Grauslys, Arturas; Larralde, Martin; Yokochi, Masashi; Kobayashi, Naohiro; Porzel, Andrea; Griffin, Julian L; Viant, Mark R; Wishart, David S; Steinbeck, Christoph; Salek, Reza M; Neumann, Steffen

    2018-01-02

    NMR is a widely used analytical technique with a growing number of repositories available. As a result, demands for a vendor-agnostic, open data format for long-term archiving of NMR data have emerged with the aim to ease and encourage sharing, comparison, and reuse of NMR data. Here we present nmrML, an open XML-based exchange and storage format for NMR spectral data. The nmrML format is intended to be fully compatible with existing NMR data for chemical, biochemical, and metabolomics experiments. nmrML can capture raw NMR data, spectral data acquisition parameters, and where available spectral metadata, such as chemical structures associated with spectral assignments. The nmrML format is compatible with pure-compound NMR data for reference spectral libraries as well as NMR data from complex biomixtures, i.e., metabolomics experiments. To facilitate format conversions, we provide nmrML converters for Bruker, JEOL and Agilent/Varian vendor formats. In addition, easy-to-use Web-based spectral viewing, processing, and spectral assignment tools that read and write nmrML have been developed. Software libraries and Web services for data validation are available for tool developers and end-users. The nmrML format has already been adopted for capturing and disseminating NMR data for small molecules by several open source data processing tools and metabolomics reference spectral libraries, e.g., serving as storage format for the MetaboLights data repository. The nmrML open access data standard has been endorsed by the Metabolomics Standards Initiative (MSI), and we here encourage user participation and feedback to increase usability and make it a successful standard.

  19. Radioiodinated N-(2-aminoethyl)-2-chloro-4-iodobenzamide

    International Nuclear Information System (INIS)

    Ohmomo, Yoshiro; Murakami, Katsuhiko; Tanaka, Chiaki; Hirata, Masahiko; Magata, Yasuhiro; Yokoyama, Akira.

    1994-01-01

    In developing monoamine oxidase (MAO)-B specific radioligands, N-(2-aminoethyl)-2-chloro-4-[ 125 I]iodobenzamide ([ 125 I]FIBA) was conveniently synthesized from its tributylstannyl precursor by an iododestannylation reaction using sodium [ 125 I]iodide and hydrogen peroxide with high radiochemical yield. The method should be applicable for labeling with 123 I, a suitable radioisotope for in vivo imaging with single photon emission computed tomography (SPECT). In vitro binding studies using mouse brain mitochondrial preparations showed that the specific binding of [ 125 I]FIBA was saturable and of high affinity. Calculated values for K D and B max were 201 nM and 9.5 pmol/mg protein, respectively. The [ 125 I]FIBA binding was effectively prevented by MAO-B specific inhibitors (l-deprenyl, Ro 16-6491, FIBA) or substrate (β-phenethylamine). However, MAO-A specific inhibitor (clorgyline) and substrate (serotonin) had no significant effect. After an intravenous injection into mice, [ 125 I]FIBA showed high brain uptake (1.64% dose/g at 15-30 min post injection) and long retention (1.11% dose/g at 120 min post injection) in the brain. Good brain-to-blood radioactivity ratios of 2.19 and 2.41 at 60 and 120 min after injection, respectively, were obtained. The in vitro binding data and in vivo characteristics suggested that [ 125 I]FIBA is potentially useful as a probe for biological studies including specific labeling of MAO-B in vivo as well as in vitro. Moreover, the 123 I-labeled counterpart, [ 123 I]FIBA, might be valuable for non-invasive imaging and mapping of MAO-B in the living brain with SPECT. (author)

  20. NMR investigation of amine complexes of aluminium borohydride

    International Nuclear Information System (INIS)

    Bojko, G.N.; Malov, Yu.I.; Semenenko, K.N.; Shilkin, S.P.

    1976-01-01

    Spectra complexes of composition AlI 3 NH 2 Me, AlI 3 .NHMe 2 , AlIsub(3-n)Clsub(n).4N 2 H 4 , where I=BH 4 , where n=0, 1, 2, 3, and AlI 3 .NH 3 were measured on by 11 B-NMR and double resonances 1 H-[ 11 B] and 1 H-[ 27 Al]. In complexes of composition 1:1, the resonance signals of 1 H, 11 B, and 27 Al were shifted to the strong field in comparison with the signal position in free AlI 3 . The strongest changes of shielding were observed for Al due to symmetry changes from the planar in AlI 3 to tetrahedral in complexes. The donor activity of ligands in relation to AlI 3 changes in the order: NMe 3 >NHMe 2 >NH 2 Me>NH 3 . No proof of the existence of a bridge structure in the complexes was obtained. The observed spectra show an equivalence of all H atoms on B. For a temperature decrease, an averaging of the spin-spin interaction of the protons with B and Al was observed. At -80 0 , a narrow singlet is observed showing the equivalance of H atoms in BH 4 - and a full isolation of interactions H-B and H-Al

  1. Software Library for Bruker TopSpin NMR Data Files

    Energy Technology Data Exchange (ETDEWEB)

    2016-10-14

    A software library for parsing and manipulating frequency-domain data files that have been processed using the Bruker TopSpin NMR software package. In the context of NMR, the term "processed" indicates that the end-user of the Bruker TopSpin NMR software package has (a) Fourier transformed the raw, time-domain data (the Free Induction Decay) into the frequency-domain and (b) has extracted the list of NMR peaks.

  2. Constraints on global oceanic emissions of N2O from observations and models

    Science.gov (United States)

    Buitenhuis, Erik T.; Suntharalingam, Parvadha; Le Quéré, Corinne

    2018-04-01

    We estimate the global ocean N2O flux to the atmosphere and its confidence interval using a statistical method based on model perturbation simulations and their fit to a database of ΔpN2O (n = 6136). We evaluate two submodels of N2O production. The first submodel splits N2O production into oxic and hypoxic pathways following previous publications. The second submodel explicitly represents the redox transformations of N that lead to N2O production (nitrification and hypoxic denitrification) and N2O consumption (suboxic denitrification), and is presented here for the first time. We perturb both submodels by modifying the key parameters of the N2O cycling pathways (nitrification rates; NH4+ uptake; N2O yields under oxic, hypoxic and suboxic conditions) and determine a set of optimal model parameters by minimisation of a cost function against four databases of N cycle observations. Our estimate of the global oceanic N2O flux resulting from this cost function minimisation derived from observed and model ΔpN2O concentrations is 2.4 ± 0.8 and 2.5 ± 0.8 Tg N yr-1 for the two N2O submodels. These estimates suggest that the currently available observational data of surface ΔpN2O constrain the global N2O flux to a narrower range relative to the large range of results presented in the latest IPCC report.

  3. NMR imaging of the cardiovascular system

    International Nuclear Information System (INIS)

    Canby, R.C.; Evanochko, W.T.; Pohost, G.M.

    1986-01-01

    Proton nuclear magnetic resonance (NMR) imaging permits high-resolution tomographic and three-dimensional images of the human body to be obtained without exposure to ionizing radiation. Such imaging not only yields anatomic resolution comparable to X-ray examinations but also provides a potential means to discriminate between healthy tissue and diseased tissue. This potential is based on certain NMR properties known as relaxation times, which determine, in part, the signal intensity in an image. These properties are related to such factors as the sizes and concentrations of proteins and mobile lipids and the compartmentalization of the protons of water. Although NMR imaging (also called magnetic resonance imaging, MRI) is becoming widely available for clinical use, application to the cardiovascular system, though promising, remains primarily a research tool. Gated proton NMR imaging can generate cardiac images with excellent morphologic detail and contrast; however, its ultimate importance as a cardiovascular diagnostic modality will depend on the development of several unique applications. These applications are discussed in this paper

  4. NMR imaging of the musculoskeletal system

    International Nuclear Information System (INIS)

    Naegele, M.; Lienemann, A.; Hahn, D.

    1988-01-01

    NMR imaging now allows in vivo imaging of soft tissue hitherto undetectable by non-invasive means. This opens up excellent perspectives with regard to the diagnosis and therapy of various diseases in the field of traumatology and oncology, of which examples are discussed in this paper. (orig.) [de

  5. Fourier transform zero field NMR and NQR

    International Nuclear Information System (INIS)

    Zax, D.B.

    1985-01-01

    In many systems the chemical shifts measured by traditional high resolution solid state NMR methods are insufficiently sensitive, or the information contained in the dipole-dipole couplings is more important. In these cases, Fourier transform zero field magnetic resonance may make an important contribution. Zero field NMR and NQR is the subject of this thesis. Chapter I presents the quantum mechanical background and notational formalism for what follows. Chapter II gives a brief review of high resolution magnetic resonance methods, with particular emphasis on techniques applicable to dipole-dipole and quadrupolar couplings. Level crossings between spin-1/2 and quadrupolar spins during demagnetization transfer polarization from high to low λ nuclei. This is the basis of very high sensitivity zero field NQR measurements by field cycling. Chapter III provides a formal presentation of the high resolution Fourier transform zero field NMR method. Theoretical signal functions are calculated for common spin systems, and examples of typical spectra are presented. Chapters IV and V review the experimental progress in zero field NMR of dipole-dipole coupled spin-1/2 nuclei and for quadrupolar spin systems. Variations of the simple experiment describe in earlier chapters that use pulsed dc fields are presented in Chapter VI

  6. NMR analog of Bell's inequalities violation test

    International Nuclear Information System (INIS)

    Souza, A M; Oliveira, I S; Sarthour, R S; Magalhaes, A; Teles, J; Azevedo, E R de; Bonagamba, T J

    2008-01-01

    In this paper, we present an analog of Bell's inequalities violation test for N qubits to be performed in a nuclear magnetic resonance (NMR) quantum computer. This can be used to simulate or predict the results for different Bell's inequality tests, with distinct configurations and a larger number of qubits. To demonstrate our scheme, we implemented a simulation of the violation of the Clauser, Horne, Shimony and Holt (CHSH) inequality using a two-qubit NMR system and compared the results to those of a photon experiment. The experimental results are well described by the quantum mechanics theory and a local realistic hidden variables model (LRHVM) that was specifically developed for NMR. That is why we refer to this experiment as a simulation of Bell's inequality violation. Our result shows explicitly how the two theories can be compatible with each other due to the detection loophole. In the last part of this work, we discuss the possibility of testing some fundamental features of quantum mechanics using NMR with highly polarized spins, where a strong discrepancy between quantum mechanics and hidden variables models can be expected

  7. NMR Analysis of Some Pentacycloundecanedione Derivatives

    African Journals Online (AJOL)

    NJD

    Although many authors have commented on the difficulty of ... coming these former difficulties. Cookson's dione 19,10 .... and 2.58 ppm) is the common factor and the positions of H-2. (2.94 ppm) .... Owing to advances in NMR technology, the.

  8. Proton NMR imaging in experimental ischemic infarction

    International Nuclear Information System (INIS)

    Buonanno, F.S.; Pykett, I.L.; Brady, T.J.; Vielma, J.; Burt, C.T.; Goldman, M.R.; Hinshaw, W.S.; Pohost, G.M.; Kistler, J.P.

    1983-01-01

    Proton nuclear magnetic resonance (NMR) images depict the distribution and concentration of mobile protons modified by the relaxation times T1 and T2. Using the steady-state-free-precession (SSFP) technique, serial coronal images were obtained sequentially over time in laboratory animals with experimental ischemic infarction. Image changes were evident as early as 2 hours after carotid artery ligation, and corresponded to areas of ischemic infarction noted pathologically. Resulting SSFP images in experimental stroke are contrasted to inversion-recovery NMR images in an illustrative patient with established cerebral infarction. Bulk T1 and T2 measurements were made in vitro in three groups of gerbils: normal, those with clinical evidence of infarction, and those clinically normal after carotid ligature. Infarcted hemispheres had significantly prolonged T1 and T2 (1.47 +/- .12 sec, 76.0 +/- 9.0 msec, respectively) when compared to the contralateral hemisphere (T1 . 1.28 +/- .05 sec, T2 . 58.7 +/- 3.9 msec) or to the other two groups. These data suggest that changes in NMR parameters occur and can be detected by NMR imaging as early as two hours after carotid artery ligation

  9. Hyperpolarized NMR Probes for Biological Assays

    Directory of Open Access Journals (Sweden)

    Sebastian Meier

    2014-01-01

    Full Text Available During the last decade, the development of nuclear spin polarization enhanced (hyperpolarized molecular probes has opened up new opportunities for studying the inner workings of living cells in real time. The hyperpolarized probes are produced ex situ, introduced into biological systems and detected with high sensitivity and contrast against background signals using high resolution NMR spectroscopy. A variety of natural, derivatized and designed hyperpolarized probes has emerged for diverse biological studies including assays of intracellular reaction progression, pathway kinetics, probe uptake and export, pH, redox state, reactive oxygen species, ion concentrations, drug efficacy or oncogenic signaling. These probes are readily used directly under natural conditions in biofluids and are often directly developed and optimized for cellular assays, thus leaving little doubt about their specificity and utility under biologically relevant conditions. Hyperpolarized molecular probes for biological NMR spectroscopy enable the unbiased detection of complex processes by virtue of the high spectral resolution, structural specificity and quantifiability of NMR signals. Here, we provide a survey of strategies used for the selection, design and use of hyperpolarized NMR probes in biological assays, and describe current limitations and developments.

  10. Structural Studies of Biological Solids Using NMR

    Science.gov (United States)

    Ramamoorthy, Ayyalusamy

    2011-03-01

    High-resolution structure and dynamics of biological molecules are important in understanding their function. While studies have been successful in solving the structures of water-soluble biomolecules, it has been proven difficult to determine the structures of membrane proteins and fibril systems. Recent studies have shown that solid-state NMR is a promising technique and could be highly valuable in studying such non-crystalline and non-soluble biosystems. I will present strategies to study the structures of such challenging systems and also about the applications of solid-state NMR to study the modes of membrane-peptide interactions for a better assessment of the prospects of antimicrobial peptides as substitutes to antibiotics in the control of human disease. Our studies on the mechanism of membrane disruption by LL-37 (a human antimicrobial peptide), analogs of the naturally occurring antimicrobial peptide magainin2 extracted from the skin of the African frog Xenopus Laevis, and pardaxin will be presented. Solid-state NMR experiments were used to determine the secondary structure, dynamics and topology of these peptides in lipid bilayers. Similarities and difference in the cell-lysing mechanism, and their dependence on the membrane composition, of these peptides will be discussed. Atomic-level resolution NMR structures of amyloidogenic proteins revealing the misfolding pathway and early intermediates that play key roles in amyloid toxicity will also be presented.

  11. Synthesis and NMR elucidation of novel pentacycloundecane ...

    African Journals Online (AJOL)

    NICO

    SYNTHESIS AND NMR ELUCIDATION OF NOVEL. PENTACYCLOUNDECANE DERIVED PEPTIDES. Rajshekhar Karpoormath, a. Oluseye K. Onajole, a. Thavendran Govender, b. Glenn E. M. Maguire, a and Hendrik G. Kruger a* a. School of Chemistry, University of KwaZulu-Natal, Durban 4001, South Africa b. School of ...

  12. The bar coil for NMR tomograph

    International Nuclear Information System (INIS)

    Bogorodzki, P.; Piatkowski, A.; Wasielewski, J.

    1995-01-01

    The bar coil (bi-planar) for the NMR tomograph, designed for medical diagnostics, has been described. The tests of coil shown that it generates good homogenous magnetic field in a big volume what results in improving of the signal-to-noise ratio

  13. NMR characterization of polymers: Review and update

    Science.gov (United States)

    NMR spectroscopy is a major technique for the characterization and analysis of polymers. A large number of methodologies have been developed in both the liquid and the solid state, and the literature has grown considerably (1-5). The field now covers a broad spectrum of activities, including polym...

  14. Some exercises in quantitative NMR imaging

    International Nuclear Information System (INIS)

    Bakker, C.J.G.

    1985-01-01

    The articles represented in this thesis result from a series of investigations that evaluate the potential of NMR imaging as a quantitative research tool. In the first article the possible use of proton spin-lattice relaxation time T 1 in tissue characterization, tumor recognition and monitoring tissue response to radiotherapy is explored. The next article addresses the question whether water proton spin-lattice relaxation curves of biological tissues are adequately described by a single time constant T 1 , and analyzes the implications of multi-exponentiality for quantitative NMR imaging. In the third article the use of NMR imaging as a quantitative research tool is discussed on the basis of phantom experiments. The fourth article describes a method which enables unambiguous retrieval of sign information in a set of magnetic resonance images of the inversion recovery type. The next article shows how this method can be adapted to allow accurate calculation of T 1 pictures on a pixel-by-pixel basis. The sixth article, finally, describes a simulation procedure which enables a straightforward determination of NMR imaging pulse sequence parameters for optimal tissue contrast. (orig.)

  15. Structures of Biomolecules by NMR Spectroscopy

    Indian Academy of Sciences (India)

    IAS Admin

    an edge over the X-ray method as it can be used to study biomolecules ... currently as an Associate. Professor. ... Such a wealth of data is made available to the NMR ... important step towards structural characterization of a biomolecule. Box 1.

  16. NMR blood vessel imaging method and apparatus

    International Nuclear Information System (INIS)

    Riederer, S.J.

    1988-01-01

    A high speed method of forming computed images of blood vessels based on measurements of characteristics of a body is described comprising the steps of: subjecting a predetermined body area containing blood vessels of interest to, successively, applications of a short repetition time (TR) NMR pulse sequence during the period of high blood velocity and then to corresponding applications during the period of low blood velocity for successive heart beat cycles; weighting the collected imaging data from each application of the NMR pulse sequence according to whether the data was acquired during the period of high blood velocity or a period of low blood velocity of the corresponding heart beat cycle; accumulating weighted imaging data from a plurality of NMR pulse sequences corresponding to high blood velocity periods and from a plurality of NMR pulse sequences corresponding to low blood velocity periods; subtracting the weighted imaging data corresponding to each specific phase encoding acquired during the high blood velocity periods from the weighted imaging data for the same phase encoding corresponding to low blood velocity periods in order to compute blood vessel imaging data; and forming an image of the blood vessels of interest from the blood vessel imaging data

  17. Recent Advances in Targeted and Untargeted Metabolomics by NMR and MS/NMR Methods

    Energy Technology Data Exchange (ETDEWEB)

    Bingol, Kerem

    2018-04-18

    Metabolomics has made significant progress in multiple fronts in the last 18 months. This minireview aimed to give an overview of these advancements in the light of their contribution to targeted and untargeted metabolomics. New computational approaches have emerged to overcome manual absolute quantitation step of metabolites in 1D 1H NMR spectra. This provides more consistency between inter-laboratory comparisons. Integration of 2D NMR metabolomics databases under a unified web server allowed very accurate identification of the metabolites that have been catalogued in these databases. For the remaining uncatalogued and unknown metabolites, new cheminformatics approaches have been developed by combining NMR and mass spectrometry. These hybrid NMR/MS approaches accelerated the identification of unknowns in untargeted studies, and now they are allowing to profile ever larger number of metabolites in application studies.

  18. FT-IR, NMR spectroscopic and quantum mechanical investigations of two ferrocene derivatives

    Directory of Open Access Journals (Sweden)

    Ö. Alver

    2017-07-01

    Full Text Available New ferrocene derivatives as N-(3-piperidin-1-ylpropylferrocenamide (Fc-3ppa and N-(pyridine-3-ylmethylferrocenamide (Fc-3pica and structural investigations were carried out with 1H, 13C, DEPT 45 or 135, HETCOR, COSY NMR and FT-IR spectroscopic techniques. Characterization of Fc-3ppa (FeC19H26N2O and Fc-3pica (FeC17H16N2O was also supported by density functional theory (DFT used by B3LYP functional and 6-31G(d or 6-311++G(d,p basis sets. From the combination of all the results, it can be clearly seen that syntheses of Fc-3ppa and Fc-3pica have been successfully achieved. Theoretical values are successfully compared against experimental data and B3LYP method is able to provide satisfactory results for predicting NMR properties and vibrational frequencies of the synthesized ferrocene based systems.

  19. Solid-state NMR spectroscopy on complex biomolecules

    NARCIS (Netherlands)

    Renault, M.A.M.; Cukkemane, A.A.; Baldus, M.

    2010-01-01

    Biomolecular applications of NMR spectroscopy are often merely associated with soluble molecules or magnetic resonance imaging. However, since the late 1970s, solid-state NMR (ssNMR) spectroscopy has demonstrated its ability to provide atomic-level insight into complex biomolecular systems ranging

  20. Polymeric proanthocyanidins 13C NMR studies of procyanidins

    Science.gov (United States)

    Lawrence J. Porter; Roger H. Newman; Lai Yeap Foo; Herbert Wong; Richard W. Hemingway

    1982-01-01

    Proanthocyanidin polymers have been shown to consist entirely of flavan-3-ol units by a combination of techniques including 13C n.m.r. spectroscopy. The 13C n.m.r. spectra of the polymers and related molecules are now considered in more detail. Prior to this study UC n.m.r. data has been published of procyanidins and...

  1. Performance of the WeNMR CS-Rosetta3 web server in CASD-NMR

    Energy Technology Data Exchange (ETDEWEB)

    Schot, Gijs van der [Uppsala University, Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology (Sweden); Bonvin, Alexandre M. J. J., E-mail: a.m.j.j.bonvin@uu.nl [Utrecht University, Faculty of Science – Chemistry, Bijvoet Center for Biomolecular Research (Netherlands)

    2015-08-15

    We present here the performance of the WeNMR CS-Rosetta3 web server in CASD-NMR, the critical assessment of automated structure determination by NMR. The CS-Rosetta server uses only chemical shifts for structure prediction, in combination, when available, with a post-scoring procedure based on unassigned NOE lists (Huang et al. in J Am Chem Soc 127:1665–1674, 2005b, doi: 10.1021/ja047109h 10.1021/ja047109h ). We compare the original submissions using a previous version of the server based on Rosetta version 2.6 with recalculated targets using the new R3FP fragment picker for fragment selection and implementing a new annotation of prediction reliability (van der Schot et al. in J Biomol NMR 57:27–35, 2013, doi: 10.1007/s10858-013-9762-6 10.1007/s10858-013-9762-6 ), both implemented in the CS-Rosetta3 WeNMR server. In this second round of CASD-NMR, the WeNMR CS-Rosetta server has demonstrated a much better performance than in the first round since only converged targets were submitted. Further, recalculation of all CASD-NMR targets using the new version of the server demonstrates that our new annotation of prediction quality is giving reliable results. Predictions annotated as weak are often found to provide useful models, but only for a fraction of the sequence, and should therefore only be used with caution.

  2. Performance of the WeNMR CS-Rosetta3 web server in CASD-NMR

    International Nuclear Information System (INIS)

    Schot, Gijs van der; Bonvin, Alexandre M. J. J.

    2015-01-01

    We present here the performance of the WeNMR CS-Rosetta3 web server in CASD-NMR, the critical assessment of automated structure determination by NMR. The CS-Rosetta server uses only chemical shifts for structure prediction, in combination, when available, with a post-scoring procedure based on unassigned NOE lists (Huang et al. in J Am Chem Soc 127:1665–1674, 2005b, doi: 10.1021/ja047109h 10.1021/ja047109h ). We compare the original submissions using a previous version of the server based on Rosetta version 2.6 with recalculated targets using the new R3FP fragment picker for fragment selection and implementing a new annotation of prediction reliability (van der Schot et al. in J Biomol NMR 57:27–35, 2013, doi: 10.1007/s10858-013-9762-6 10.1007/s10858-013-9762-6 ), both implemented in the CS-Rosetta3 WeNMR server. In this second round of CASD-NMR, the WeNMR CS-Rosetta server has demonstrated a much better performance than in the first round since only converged targets were submitted. Further, recalculation of all CASD-NMR targets using the new version of the server demonstrates that our new annotation of prediction quality is giving reliable results. Predictions annotated as weak are often found to provide useful models, but only for a fraction of the sequence, and should therefore only be used with caution

  3. Upland Trees Contribute to Exchange of Nitrous Oxide (N2O) in Forest Ecosystems

    Science.gov (United States)

    Tian, H.; Thompson, R.; Canadell, J.; Winiwarter, W.; Machacova, K.; Maier, M.; Halmeenmäki, E.; Svobodova, K.; Lang, F.; Pihlatie, M.; Urban, O.

    2017-12-01

    The increase in atmospheric nitrous oxide (N2O) concentration contributes to the acceleration of the greenhouse effect. However, the role of trees in the N2O exchange of forest ecosystems is still an open question. While the soils of temperate and boreal forests were shown to be a natural source of N2O, trees have been so far overlooked in the forest N2O inventories. We determined N2O fluxes in common tree species of boreal and temperate forests: Scots pine (Pinus sylvestris), Norway spruce (Picea abies), downy and silver birch (Betula pubescens, B. pendula), and European beech (Fagus sylvatica). We investigated (1) whether these tree species exchange N2O with the atmosphere under natural field conditions, (2) how the tree N2O fluxes contribute to the forest N2O balance, and (3) whether these fluxes show seasonal dynamics. The studies were performed in a boreal forest (SMEAR II station, Finland; June 2014 - May 2015) and two temperate mountain forests (White Carpathians, Czech Republic; Black Forest, Germany; June and July 2015). Fluxes of N2O in mature tree stems and forest floor were measured using static chamber systems followed by chromatographic and photo-acoustic analyses of N2O concentration changes. Pine, spruce and birch trees were identified as net annual N2O sources. Spruce was found the strongest emitter (0.27 mg ha-1 h-1) amounting thus up to 2.5% of forest floor N2O emissions. All tree species showed a substantial seasonality in stem N2O flux that was related to their physiological activity and climatic variables. In contrast, stems of beech trees growing at soils consuming N2O may act as a substantial sink of N2O from the atmosphere. Consistent N2O consumption by tree stems ranging between -12.1 and -35.2 mg ha-1 h-1 and contributing by up to 3.4% to the forest floor N2O uptake is a novel finding in contrast to current studies presenting trees as N2O emitters. To understand these fluxes, N2O exchange of photoautotrophic organisms associated with

  4. First NMR Experiments in the Hybrid, 40T and beyond: A challenge to traditional NMR instrumentation

    Science.gov (United States)

    Reyes, Arneil P.

    2001-03-01

    The recent commissioning of the continuous 45T hybrid magnet at NHMFL has opened new horizon for science but carried with it new challenges that forced NMR spectroscopists to reevaluate the traditional approach to NMR instrumentation. Very recently, a world record frequency at 1.5GHz has been achieved, signaling the new era of NMR probe designs that may someday blur the distinction between the classic NMR and millimeter-wave spectroscopies. No longer can we ignore stray capacitances and exposed leads in the terrain where every millimeter of cable counts. The challenge brought about by ever increasing fields and consequently, frequency, requirements has stimulated ingenuity among scientists. This is eased by accelerated growth in RF communications and computing technologies that made available advanced devices with more speed, power, bandwidth, noise immunity, flexibility, and complexity in small space at very low costs. Utilization of these devices have been paramount consideration in cutting-edge designs at NHMFL for Condensed Matter NMR and will be described in this talk. I will also discuss a number of first >33T NMR experiments to date utilizing the strength of the field to expose, as well as to induce occurrence of, new physical phenomena in condensed matter and which resulted in better understanding of the physics of materials. This work has been a result of continuing collaboration with P. L Kuhns, W. G. Moulton, W. P. Halperin (NU), and W. G. Clark (UCLA). The NHMFL is supported through the National Science Foundation and the State of Florida.

  5. Theoretical studies for the N2N2O van der Waals complex: The potential energy surface, intermolecular vibrations, and rotational transition frequencies

    International Nuclear Information System (INIS)

    Zheng, Rui; Zheng, Limin; Yang, Minghui; Lu, Yunpeng

    2015-01-01

    Theoretical studies of the potential energy surface (PES) and bound states are performed for the N 2N 2 O van der Waals (vdW) complex. A four-dimensional intermolecular PES is constructed at the level of single and double excitation coupled-cluster method with a non-iterative perturbation treatment of triple excitations [CCSD(T)] with aug-cc-pVTZ basis set supplemented with bond functions. Two equivalent T-shaped global minima are located, in which the O atom of N 2 O monomer is near the N 2 monomer. The intermolecular fundamental vibrational states are assigned by inspecting the orientation of the nodal surface of the wavefunctions. The calculated frequency for intermolecular disrotation mode is 23.086 cm −1 , which is in good agreement with the available experimental data of 22.334 cm −1 . A negligible tunneling splitting with the value of 4.2 MHz is determined for the ground vibrational state and the tunneling splitting increases as the increment of the vibrational frequencies. Rotational levels and transition frequencies are calculated for both isotopomers 14 N 2N 2 O and 15 N 2N 2 O. The accuracy of the PES is validated by the good agreement between theoretical and experimental results for the transition frequencies and spectroscopic parameters

  6. Uncertainty modelling to evaluate nitrogen balances as a tool to determine N2 and N2O formation in ammonia bioscrubbers

    NARCIS (Netherlands)

    Estelles, F.; Calvet, S.; Melse, R.W.; Ogink, N.W.M.

    2012-01-01

    Biological scrubbers aim at reducing gaseous ammonia emissions by transferring it to a water phase followed by conversion to nitrite and nitrate. A small part of the removed nitrogen may be emitted as N2 and N2O produced as a result of denitrification processes. Due to the large greenhouse warming

  7. Influence of N2 partial pressure on structural and microhardness properties of TiN/ZrN multilayers deposited by Ar/N2 vacuum arc discharge

    Science.gov (United States)

    Naddaf, M.; Abdallah, B.; Ahmad, M.; A-Kharroub, M.

    2016-08-01

    The influence of N2 partial pressure on structural, mechanical and wetting properties of multilayered TiN/ZrN thin films deposited on silicon substrates by vacuum arc discharge of (N2 + Ar) gas mixtures is investigated. X-ray diffraction (XRD) results show that the average texturing coefficient of (1 1 1) orientation and the grain size of both TiN and ZrN individual layers increase with increasing the N2 partial pressure. The Rutherford back scattering (RBS) measurements and analysis reveal that incorporation of the nitrogen in the film increases with increasing the N2 partial pressure and both TiN and ZrN individual layers have a nitrogen over-stoichiometry for N2 partial pressure ⩾50%. The change in the film micro-hardness is correlated to the changes in crystallographic texture, grain size, stoichiometry and the residual stress in the film as a function of the N2 partial pressure. In particular, stoichiometry of ZrN and TiN individual is found to play the vital role in determining the multilayer hardness. The multilayer film deposited at N2 partial pressure of 25% has the best stoichiometric ratio of both TiN and ZrN layers and the highest micro-hardness of about 32 GPa. In addition, water contact angle (WCA) measurements and analysis show a decrease in the work of adhesion on increasing the N2 partial pressure.

  8. Influence of N_2 partial pressure on structural and microhardness properties of TiN/ZrN multilayers deposited by Ar/N_2 vacuum arc discharge

    International Nuclear Information System (INIS)

    Naddaf, M.; Abdallah, B.; Ahmad, M.; A-Kharroub, M.

    2016-01-01

    The influence of N_2 partial pressure on structural, mechanical and wetting properties of multilayered TiN/ZrN thin films deposited on silicon substrates by vacuum arc discharge of (N_2 + Ar) gas mixtures is investigated. X-ray diffraction (XRD) results show that the average texturing coefficient of (1 1 1) orientation and the grain size of both TiN and ZrN individual layers increase with increasing the N_2 partial pressure. The Rutherford back scattering (RBS) measurements and analysis reveal that incorporation of the nitrogen in the film increases with increasing the N_2 partial pressure and both TiN and ZrN individual layers have a nitrogen over-stoichiometry for N_2 partial pressure ⩾50%. The change in the film micro-hardness is correlated to the changes in crystallographic texture, grain size, stoichiometry and the residual stress in the film as a function of the N_2 partial pressure. In particular, stoichiometry of ZrN and TiN individual is found to play the vital role in determining the multilayer hardness. The multilayer film deposited at N_2 partial pressure of 25% has the best stoichiometric ratio of both TiN and ZrN layers and the highest micro-hardness of about 32 GPa. In addition, water contact angle (WCA) measurements and analysis show a decrease in the work of adhesion on increasing the N_2 partial pressure.

  9. Isotope signatures of N2O emitted from vegetable soil: Ammonia oxidation drives N2O production in NH4(+)-fertilized soil of North China.

    Science.gov (United States)

    Zhang, Wei; Li, Yuzhong; Xu, Chunying; Li, Qiaozhen; Lin, Wei

    2016-07-08

    Nitrous oxide (N2O) is a potent greenhouse gas. In North China, vegetable fields are amended with high levels of N fertilizer and irrigation water, which causes massive N2O flux. The aim of this study was to determine the contribution of microbial processes to N2O production and characterize isotopic signature effects on N2O source partitioning. We conducted a microcosm study that combined naturally abundant isotopologues and gas inhibitor techniques to analyze N2O flux and its isotopomer signatures [δ(15)N(bulk), δ(18)O, and SP (intramolecular (15)N site preference)] that emitted from vegetable soil after the addition of NH4(+) fertilizers. The results show that ammonia oxidation is the predominant process under high water content (70% water-filled pore space), and nitrifier denitrification contribution increases with increasing N content. δ(15)N(bulk) and δ(18)O of N2O may not provide information about microbial processes due to great shifts in precursor signatures and atom exchange, especially for soil treated with NH4(+) fertilizer. SP and associated two end-member mixing model are useful to distinguish N2O source and contribution. Further work is needed to explore isotopomer signature stability to improve N2O microbial process identification.

  10. Hairy black holes in N=2 gauged supergravity

    Energy Technology Data Exchange (ETDEWEB)

    Faedo, Federico [Dipartimento di Fisica, Università di Milano, Via Celoria 16, 20133 Milano (Italy); Klemm, Dietmar; Nozawa, Masato [Dipartimento di Fisica, Università di Milano, Via Celoria 16, 20133 Milano (Italy); INFN, Sezione di Milano, Via Celoria 16, 20133 Milano (Italy)

    2015-11-06

    We construct black holes with scalar hair in a wide class of four-dimensional N=2 Fayet-Iliopoulos gauged supergravity theories that are characterized by a prepotential containing one free parameter. Considering the truncated model in which only a single real scalar survives, the theory is reduced to an Einstein-scalar system with a potential, which admits at most two AdS critical points and is expressed in terms of a real superpotential. Our solution is static, admits maximally symmetric horizons, asymptotically tends to AdS space corresponding to an extremum of the superpotential, but is disconnected from the Schwarzschild-AdS family. The condition under which the spacetime admits an event horizon is addressed for each horizon topology. It turns out that for hyperbolic horizons the black holes can be extremal. In this case, the near-horizon geometry is AdS{sub 2}×H{sup 2}, where the scalar goes to the other, non-supersymmetric, critical point of the potential. Our solution displays fall-off behaviours different from the standard one, due to the fact that the mass parameter m{sup 2}=−2ℓ{sup −2} at the supersymmetric vacuum lies in a characteristic range m{sub BF}{sup 2}≤m{sup 2}

  11. Catalytic properties of extraframework iron-containing species in ZSM-5 for N2O decomposition

    NARCIS (Netherlands)

    Li, G.; Pidko, E.A.; Filot, I.A.W.; Santen, van R.A.; Li, Can; Hensen, E.J.M.

    2013-01-01

    The reactivity of mononuclear and binuclear iron-containing complexes in ZSM-5 zeolite for catalytic N2O decomposition has been investigated by periodic DFT calculations and microkinetic modeling. On mononuclear sites, the activation of a first N2O molecule is favorable. The rate of catalytic N2O

  12. Uncertainty propagation analysis of an N2O emission model at the plot and landscape scale

    NARCIS (Netherlands)

    Nol, L.; Heuvelink, G.B.M.; Veldkamp, A.; Vries, de W.; Kros, J.

    2010-01-01

    Nitrous oxide (N2O) emission from agricultural land is an important component of the total annual greenhouse gas (GHG) budget. In addition, uncertainties associated with agricultural N2O emissions are large. The goals of this work were (i) to quantify the uncertainties of modelled N2O emissions

  13. Distinguishing sources of N2O in European grasslands by stable isotope analysis

    NARCIS (Netherlands)

    Wrage, N.; Lauf, J.; Prado, del A.; Pinto, M.; Pietrzak, S.; Yamulki, S.; Oenema, O.; Gebauer, G.

    2004-01-01

    Nitrifiers and denitrifiers are the main producers of the greenhouse gas nitrous oxide (N2O). Knowledge of the respective contributions of each of these microbial groups to N2O production is a prerequisite for the development of effective mitigation strategies for N2O. Often, the differentiation is

  14. Influenza AH1N2 Viruses, United Kingdom, 2001?02 Influenza Season

    OpenAIRE

    Ellis, Joanna S.; Alvarez-Aguero, Adriana; Gregory, Vicky; Lin, Yi Pu; Hay, A.; Zambon, Maria C.

    2003-01-01

    During the winter of 2001?02, influenza AH1N2 viruses were detected for the first time in humans in the U.K. The H1N2 viruses co-circulated with H3N2 viruses and a very small number of H1N1 viruses and were isolated in the community and hospitalized patients, predominantly from children

  15. Nitrous Oxide (N2O) emissions from human waste in 1970-2050

    NARCIS (Netherlands)

    Strokal, M.; Kroeze, C.

    2014-01-01

    Nitrous oxide (N2O) is an important contributor to climate change. Human waste is an important source of N2O emissions in several world regions, and its share in global emissions may increase in the future. In this paper we, therefore, address N2O emission from human waste: collected (from treatment

  16. N=2 superconformal models, Landau-Ginsburg Hamiltonians and the ε expansion

    International Nuclear Information System (INIS)

    Howe, P.S.; West, P.C.

    1989-01-01

    The anomalous dimensions of a class of operators, operator product expansions and the central change, c, are calculated in a family of N=2 supersymmetric two-dimensional Landau-Ginsburg models. The results allow the identification of these theories with N=2 minimal superconformal models. A key role is placed by the N=2 non-renormalization theorem. (orig.)

  17. Influenza A(H9N2) Virus, Myanmar, 2014-2015.

    Science.gov (United States)

    Lin, Thant Nyi; Nonthabenjawan, Nutthawan; Chaiyawong, Supassama; Bunpapong, Napawan; Boonyapisitsopa, Supanat; Janetanakit, Taveesak; Mon, Pont Pont; Mon, Hla Hla; Oo, Kyaw Naing; Oo, Sandi Myint; Mar Win, Mar; Amonsin, Alongkorn

    2017-06-01

    Routine surveillance of influenza A virus was conducted in Myanmar during 2014-2015. Influenza A(H9N2) virus was isolated in Shan State, upper Myanmar. Whole-genome sequencing showed that H9N2 virus from Myanmar was closely related to H9N2 virus of clade 4.2.5 from China.

  18. Towards an agronomic assessment of N2O emissions: a case study for arable crops

    NARCIS (Netherlands)

    Groenigen, van J.W.; Velthof, G.L.; Oenema, O.; Groenigen, van K.J.; Kessel, van C.

    2010-01-01

    Agricultural soils are the main anthropogenic source of nitrous oxide (N2O), largely because of nitrogen (N) fertilizer use. Commonly, N2O emissions are expressed as a function of N application rate. This suggests that smaller fertilizer applications always lead to smaller N2O emissions. Here we

  19. 40 CFR 721.520 - Alanine, N-(2-carboxyethyl)-N-alkyl-, salt.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alanine, N-(2-carboxyethyl)-N-alkyl... Specific Chemical Substances § 721.520 Alanine, N-(2-carboxyethyl)-N-alkyl-, salt. (a) Chemical substance... alanine, N-(2-carboxyethyl)-N- alkyl-, salt (P-89-336) is subject to reporting under this section for the...

  20. The interaction between silver and N2O in relation to the oxidative dehydrogenation of methanol

    NARCIS (Netherlands)

    Lefferts, Leonardus; van Ommen, J.G.; Ross, J.R.H.

    1988-01-01

    The interaction of N2O with pure silver at temperatures up to 900 °C has been studied using temperature-programmed reduction and desorption; the interaction is compared with that of oxygen with silver. The effect of addition of N2O, as well as of the complete replacement of oxygen by N2O, on the

  1. When the Sun's Away, N2O5 Comes Out to Play: An Updated Analysis of Ambient N2O5 Heterogeneous Chemistry

    Science.gov (United States)

    McDuffie, E. E.; Brown, S. S.

    2017-12-01

    The heterogeneous chemistry of N2O5 impacts the budget of tropospheric oxidants, which directly controls air quality at Earth's surface. The reaction between gas-phase N2O5 and aerosol particles occurs largely at night, and is therefore more important during the less-intensively-studied winter season. Though N2O5-aerosol interactions are vital for the accurate understanding and simulation of tropospheric chemistry and air quality, many uncertainties persist in our understanding of how various environmental factors influence the reaction rate and probability. Quantitative and accurate evaluation of these factors directly improves the predictive capabilities of atmospheric models, used to inform mitigation strategies for wintertime air pollution. In an update to last year's presentation, The Wintertime Fate of N2O5: Observations and Box Model Analysis for the 2015 WINTER Aircraft Campaign, this presentation will focus on recent field results regarding new information about N2O5 heterogeneous chemistry and future research directions.

  2. The N2 paradox: similar outcomes of pre- and postoperatively identified single-zone N2a positive non-small-cell lung cancer.

    Science.gov (United States)

    Tsitsias, Thomas; Boulemden, Anas; Ang, Keng; Nakas, Apostolos; Waller, David A

    2014-05-01

    Resection of N2a non-small-cell lung cancer (NSCLC) diagnosed preoperatively is controversial but there is support for resection of unexpected N2 disease discovered at surgery. Since the seventh TNM edition, we have intentionally resected clinical N2a disease. To validate this policy, we determined prognostic factors associated with all resected N2 disease. From a prospective database of 1131 consecutive patients undergoing elective resection for primary lung cancer over a period of 8 years, we identified 68 patients (35 females (51.4%), mean age 66 years, standard deviation (SD) 9 years) who had pathological N2 disease. All patients had positron emission computed tomography (CT-PET) staging and selective mediastinoscopy. A Cox-regression analysis was performed to identify prognostic factors. At a median follow-up of 38.7 months (standard error 10, 95% confidence interval (CI) 19.0-58.4), the overall median survival was 22.2 months (95% CI 14.6-29.8) with 1-, 2- and 5-year survival rates of 63.3, 46.6 and 13.2%, respectively. Survival after resection of pN2 disease is adversely affected by the need for pneumonectomy, multizone pN2b involvement and by non-compliance with adjuvant chemotherapy. Pathological involvement of the subcarinal zone but no other zone appears to be associated with an adverse prognosis (hazard ratio (HR) 1.87, P = 0.063). Importantly, long-term survival is not different between those patients who have a negative preoperative PET-CT scan and yet are found to have pN2 after resection, and those who are single-zone cN2a positive before resection on PET-CT scan (HR 1.37, P = 0.335). Our results support a policy of intentionally resecting single-zone N2a NSCLC identified preoperatively as part of a multimodality therapy.

  3. Direct 13C NMR Detection in HPLC Hyphenation Mode

    DEFF Research Database (Denmark)

    Wubshet, Sileshi Gizachew; Johansen, Kenneth; Nyberg, Nils

    2012-01-01

    Solid phase extraction (SPE) was introduced as a crucial step in the HPLC-SPE-NMR technique to enable online analyte enrichment from which proton-detected NMR experiments on submicrogram amounts from complex mixtures were possible. However, the significance of direct-detected (13)C NMR experiments...... application of HPLC-SPE-NMR analysis using direct-detected (13)C NMR spectra. HPLC column loading, accumulative SPE trappings, and the effect of different elution solvents were evaluated and optimized. A column loading of approximately 600 mug of a prefractionated triterpenoid mixture, six trappings...

  4. Use of NMR as an online sensor in industrial processes

    International Nuclear Information System (INIS)

    Andrade, Fabiana Diuk de

    2012-01-01

    Nuclear magnetic resonance (NMR) is one of the most versatile analytical techniques for chemical, biochemical and medical applications. Despite this great success, NMR is seldom used as a tool in industrial applications. The first application of NMR in flowing samples was published in 1951. However, only in the last ten years Flow NMR has gained momentum and new and potential applications have been proposed. In this review we present the historical evolution of flow or online NMR spectroscopy and imaging, and current developments for use in the automation of industrial processes. (author)

  5. Spatial Variations in N2O Concentration and Isotopomer Composition off the Peru Coast

    Science.gov (United States)

    Bourbonnais, A.; Letscher, R. T.; Kock, A.; Bange, H. W.; Altabet, M. A.

    2016-02-01

    Nitrous oxide (N2O) is a potent greenhouse gas and stratospheric ozone depleting substance. The ocean is an important source of N2O to the atmosphere, accounting for up to about 30% of total emissions. However, the factors controlling N2O production and consumption in oceanic environments are still not understood nor constrained. N2O is a by-product of aerobic nitrification, and is formed by two different pathways: 1) the decomposition of hydroxylamine, an intermediate during ammonium oxidation to nitrite, or 2) the reduction of nitrite to N2O (nitrifier-denitrification). N2O is also an intermediate during denitrification under anoxic conditions. In this study, we measured N2O concentrations and isotopomer ratios, as well as O2, nutrient and biogenic N2 concentrations and the isotopic compositions of nitrate, nitrite and biogenic N2 at several coastal stations during two cruises off the Peru coast (6-14°S, 75-81°W) in December 2012 and January 2013. [N2O] varied from below equilibrium values in the OMZ to up to 238 nmol L-1 at 11 m depth at one of the shallowest stations. The isotopic composition of N2O (bulk δ15N: -5 to 30‰, δ18O: 41 to 95‰, and Site Preference: -3 to 65‰) also varied widely, with important differences between stations. Our results show a strong spatial heterogeneity in the mechanisms controlling N2O production and consumption in coastal upwelling regions, which should be taken into account in oceanic N2O models. We will discuss the contributions from different N2O production processes responsible for the observed extreme N2O accumulations.

  6. Fluid simulation of species concentrations in capacitively coupled N2/Ar plasmas: Effect of gas proportion

    Science.gov (United States)

    Liang, Ying-Shuang; Liu, Gang-Hu; Xue, Chan; Liu, Yong-Xin; Wang, You-Nian

    2017-05-01

    A two-dimensional self-consistent fluid model and the experimental diagnostic are employed to investigate the dependencies of species concentrations on the gas proportion in the capacitive N2/Ar discharges operated at 60 MHz, 50 Pa, and 140 W. The results indicate that the N2/Ar proportion has a considerable impact on the species densities. As the N2 fraction increases, the electron density, as well as the Ar+ and Arm densities, decreases remarkably. On the contrary, the N2 + density is demonstrated to increase monotonically with the N2 fraction. Moreover, the N density is observed to increase significantly with the N2 fraction at the N2 fractions below 40%, beyond which it decreases slightly. The electrons are primarily generated via the electron impact ionization of the feed gases. The electron impact ionization of Ar essentially determines the Ar+ density. For the N2 + production, the charge transition process between the Ar+ ions and the feed gas N2 dominates at low N2 fraction, while the electron impact ionization of N2 plays the more important role at high N2 fraction. At any gas mixtures, more than 60% Arm atoms are generated through the radiative decay process from Ar(4p). The dissociation of the feed gas N2 by the excited Ar atoms and by the electrons is responsible for the N formation at low N2 fraction and high N2 fraction, respectively. To validate the simulation results, the floating double probe and the optical emission spectroscopy are employed to measure the total positive ion density and the emission intensity originating from Ar(4p) transitions, respectively. The results from the simulation show a qualitative agreement with that from the experiment, which indicates the reliable model.

  7. Editorial L&E, v.7, n.2, 2013.

    Directory of Open Access Journals (Sweden)

    Rede Conpadre

    2013-04-01

    Full Text Available Editorial L&E, v.7, n.2, 2013 Neste ano, o prêmio jovem cientista do Conselho Nacional de Pesquisa e Desenvolvimento (CNPq adotou como tema central “Água. Desafios da Sociedade”. Esta edição da Revista Labor & Engenho (L&E, v.7, n.2, 2013 reúne oito artigos, todos voltados às questões do desenvolvimento regional, enfocando principalmente a ordenação e o uso do território, o patrimônio local e a conformação da paisagem. Todavia, três deles são voltados diretamente para as questões de uso e ocupação do solo e, água. A Lei 9433/97 trouxe muitos avanços em relação ao antigo código das águas de 1930. Definiu como espaço territorial para o planejamento e gestão, a bacia hidrográfica; definiu que a prática do planejamento e gestão devem integrar com o planejamento de uso e ocupação do solo; assim como questões de quantidade e qualidade da água devem estar associadas. Foram definidos novos instrumentos para a gestão como o plano de recursos hídricos; o sistema de informações; a outorga e; a cobrança pela captação de água bruta. Além de definir a Política Nacional para Gestão de Recursos Hídricos, a Lei apresenta o Sistema Nacional para Gestão de Recursos Hídricos, que entre outros, atribui o domínio governamental das águas nos níveis Federativo e Estadual. Desde a regulamentação da Lei, não se pode negar os avanços. Mas é um consenso, da práxis e do mundo acadêmico-científico, que há muitas lacunas a serem preenchidas até que se possa observar o controle efetivo através das outorgas concedidas e da cobrança, a elaboração e integração do Plano Nacional (já regulamentado e os Planos Estaduais de Recursos Hídricos (alguns já regulamentados, o Sistema Nacional de Informações sobre Recursos Hídricos, a gestão participativa, a racionalidade, as práticas de conservação da água, o manejo adequado e, equilíbrio entre escassez e excessos de águas pluviais, a sustentabilidade atrav

  8. Elucidating source processes of N2O fluxes following grassland-to-field-conversion using isotopologue signatures of soil-emitted N2O

    Science.gov (United States)

    Roth, G.; Giesemann, A.; Well, R.; Flessa, H.

    2012-04-01

    Conversion of grassland to arable land often causes enhanced nitrous oxide (N2O) emissions to the atmosphere. This is due to the tillage of the sward and subsequent decomposition of organic matter. Prediction of such effects is uncertain so far because emissions may differ depending on site and soil conditions. The processes of N2O turnover (nitrification, production by bacterial or fungal denitrifiers, bacterial reduction to N2) are difficult to identify, however. Isotopologue signatures of N2O such as δ18O, average δ15N (δ15Nbulk) and 15N site preference (SP = difference in δ15N between the central and peripheral N positions of the asymmetric N2O molecule) can be used to characterize N2O turnover processes using the known ranges of isotope effects of the various N2O pathways. We aim to evaluate the impact of grassland-to-field-conversion on N2O fluxes and the governing processes using isotopic signatures of emitted N2O. At two sites, in Kleve (North Rhine-Westphalia, Germany, conventional farming) and Trenthorst (Schleswig-Holstein, Germany, organic farming), a four times replicated plot experiment with (i) mechanical conversion (ploughing, maize), (ii) chemical conversion (broadband herbicide, maize per direct seed) and (iii) continuous grassland as reference was started in April 2010. In Trenthorst we additionally established a (iv) field with continuous maize cultivation as further reference. Over a period of two years, mineral nitrogen (Nmin) content was measured weekly on soil samples taken from 0-10 cm and 10-30 cm depth. Soil water content and N2O emissions were measured weekly as well. Gas samples were collected using a closed chamber system. Isotope ratio mass spectrometry was carried out on gas samples from selected high flux events to determine δ18O, δ15Nbulk and SP of N2O. δ18O and SP of N2O exhibited a relatively large range (32 to 72 ‰ and 6 to 34 ‰, respectively) indicating highly variable process dynamics. The data-set is grouped

  9. [Characteristics of N2, N2O, NO, CO2 and CH4 Emissions in Anaerobic Condition from Sandy Loam Paddy Soil].

    Science.gov (United States)

    Cao, Na; Wang, Rui; Liao, Ting-ting; Chen, Nuo; Zheng, Xun-hua; Yao, Zhi-sheng; Zhang, Hai; Butterbach-Bahl, Klaus

    2015-09-01

    Understanding the characteristics of the production of nitrogen gases (N2, N2O and NO), CO2 and CH4 in anaerobic paddy soils is not only a prerequisite for an improved mechanistic understanding of key microbial processes involved in the production of atmospheric greenhouse gases (GHG), but might also provide the basis for designing greenhouse gas mitigation strategies. Moreover, quantifying the composition fractions of denitrification gaseous products is of key importance for improving parameterization schemes of microbial processes in process-oriented models which are increasingly used for assessing soil GHG emissions at site and national scales. In our experiments we investigated two sandy loam soils from two paddy fields. The initial concentrations of soil nitrate and dissolved organic carbon (DOC) were set at approximately 50 mg.kg-1 and mg.kg-1, respectively, by adding a mixture solution of KNO3 and glucose. The emissions of N2, N2O NO, CO2 and CH4, as well as concentrations of carbon and nitrogen substrates for each soil sample were measured simultaneously, using a gas-flow-soil-core technique and a paralleling substrate monitoring system. The results showed that the accumulative emissions of N2, N2O and NO of the two soil samples for the entire incubation period were 6 - 8, 20, and 15 - 18 mg.kg-1, respectively. By measuring the cumulative emissions of denitrification gases (N, = N2 + N2O + NO) we were able to explain 95% to 98% of observed changes in s1ifr nilrate concentrations. The mass fractions of N2, N2O and NO emissions to Nt were approximately 15% -19%, 47% -49%, and 34% -36%, respectively. Thus, in our experiments N2O and NO were the main products of denitrification for the entire incubation period. However, as the temporal courses of hourly or daily production of the denitrification gases showed, NO production dominated and peaked firstly, and then N2O, before finally N2 became the dominant product. Our results show the high temporal dynamic of

  10. Simple control strategy for mitigating N2O emissions in phase isolated full-scale WWTPs

    DEFF Research Database (Denmark)

    Ekström, Sara Elisabet Margareta; Vangsgaard, Anna Katrine; Lemaire, Romain

    2017-01-01

    removal processes relying on nitrification and denitrification are known to produce N2O. A one year long-term study of N2O production and emissions was performed at Lynetten, Denmark’s largest WWTP. Nitrification and denitrification takes place by alternating process conditions as well as influent....... Nitrification phases were identified to produce and emit most of the N2O. High production and emissions were also associated with the afternoon loading peaks at the WWTP. During denitrification phases N2O was produced initially but consumed consequently. An effective control strategy was implemented, whereby N2...

  11. Solid-state NMR basic principles and practice

    CERN Document Server

    Apperley, David C; Hodgkinson, Paul

    2014-01-01

    Nuclear Magnetic Resonance (NMR) has proved to be a uniquely powerful and versatile tool for analyzing and characterizing chemicals and materials of all kinds. This book focuses on the latest developments and applications for "solid-state" NMR, which has found new uses from archaeology to crystallography to biomaterials and pharmaceutical science research. The book will provide materials engineers, analytical chemists, and physicists, in and out of lab, a survey of the techniques and the essential tools of solid-state NMR, together with a practical guide on applications. In this concise introduction to the growing field of solid-state nuclear magnetic resonance spectroscopy The reader will find: * Basic NMR concepts for solids, including guidance on the spin-1/2 nuclei concept * Coverage of the quantum mechanics aspects of solid state NMR and an introduction to the concept of quadrupolar nuclei * An understanding relaxation, exchange and quantitation in NMR * An analysis and interpretation of NMR data, with e...

  12. Isostructural and cage-specific replacement occurring in sII hydrate with external CO2/N2 gas and its implications for natural gas production and CO2 storage

    International Nuclear Information System (INIS)

    Seo, Young-ju; Park, Seongmin; Kang, Hyery; Ahn, Yun-Ho; Lim, Dongwook; Kim, Se-Joon; Lee, Jaehyoung; Lee, Joo Yong; Ahn, Taewoong; Seo, Yongwon; Lee, Huen

    2016-01-01

    Highlights: • The structural sustainability of sII hydrate is demonstrated during the replacement. • The experimental evidence of isostructural replacement is revealed. • The cage-specific replacement in sII hydrates allows long-term CO 2 storage. • The compositions and extent of replacement are cross-checked by GC and NMR analyses. - Abstract: A replacement technique has been regarded as a promising strategy for both CH 4 exploitation from gas hydrates and CO 2 sequestration into deep-ocean reservoirs. Most research has been focused on replacement reactions that occur in sI hydrates due to their prevalence in natural gas hydrates. However, sII hydrates in nature have been also discovered in some regions, and the replacement mechanism in sII hydrates significantly differs from that in sI hydrates. In this study, we have intensively investigated the replacement reaction of sII (C 3 H 8 + CH 4 ) hydrate by externally injecting CO 2 /N 2 (50:50) gas mixture with a primary focus on powder X-ray diffraction, Raman spectroscopy, NMR spectroscopy, and gas chromatography analyses. In particular, it was firstly confirmed that there was no structural transformation during the replacement of C 3 H 8 + CH 4 hydrate with CO 2 /N 2 gas injection, indicating that sII hydrate decomposition followed by sI hydrate formation did not occur. Furthermore, the cage-specific replacement pattern of the C 3 H 8 + CH 4 hydrate revealed that CH 4 replacement with N 2 in the small cages of sII was more significant than C 3 H 8 replacement with CO 2 in the large cages of sII. The total extent of the replacement for the C 3 H 8 + CH 4 hydrate was cross-checked by NMR and GC analyses and found to be approximately 54%. Compared to the replacement for CH 4 hydrate with CO 2 /N 2 gas, the lower extent of the replacement for the C 3 H 8 + CH 4 hydrate with CO 2 /N 2 gas was attributable to the persistent presence of C 3 H 8 in the large cages and the lower content of N 2 in the feed gas. The

  13. NMR shielding calculations across the periodic table: diamagnetic uranium compounds. 2. Ligand and metal NMR.

    Science.gov (United States)

    Schreckenbach, Georg

    2002-12-16

    In this and a previous article (J. Phys. Chem. A 2000, 104, 8244), the range of application for relativistic density functional theory (DFT) is extended to the calculation of nuclear magnetic resonance (NMR) shieldings and chemical shifts in diamagnetic actinide compounds. Two relativistic DFT methods are used, ZORA ("zeroth-order regular approximation") and the quasirelativistic (QR) method. In the given second paper, NMR shieldings and chemical shifts are calculated and discussed for a wide range of compounds. The molecules studied comprise uranyl complexes, [UO(2)L(n)](+/-)(q); UF(6); inorganic UF(6) derivatives, UF(6-n)Cl(n), n = 0-6; and organometallic UF(6) derivatives, UF(6-n)(OCH(3))(n), n = 0-5. Uranyl complexes include [UO(2)F(4)](2-), [UO(2)Cl(4)](2-), [UO(2)(OH)(4)](2-), [UO(2)(CO(3))(3)](4-), and [UO(2)(H(2)O)(5)](2+). For the ligand NMR, moderate (e.g., (19)F NMR chemical shifts in UF(6-n)Cl(n)) to excellent agreement [e.g., (19)F chemical shift tensor in UF(6) or (1)H NMR in UF(6-n)(OCH(3))(n)] has been found between theory and experiment. The methods have been used to calculate the experimentally unknown (235)U NMR chemical shifts. A large chemical shift range of at least 21,000 ppm has been predicted for the (235)U nucleus. ZORA spin-orbit appears to be the most accurate method for predicting actinide metal chemical shifts. Trends in the (235)U NMR chemical shifts of UF(6-n)L(n) molecules are analyzed and explained in terms of the calculated electronic structure. It is argued that the energy separation and interaction between occupied and virtual orbitals with f-character are the determining factors.

  14. To what extent might N2 limit dive performance in king penguins?

    Science.gov (United States)

    Fahlman, A; Schmidt, A; Jones, D R; Bostrom, B L; Handrich, Y

    2007-10-01

    A mathematical model was used to explore if elevated levels of N2, and risk of decompression sickness (DCS), could limit dive performance (duration and depth) in king penguins (Aptenodytes patagonicus). The model allowed prediction of blood and tissue (central circulation, muscle, brain and fat) N2 tensions (P(N2)) based on different cardiac outputs and blood flow distributions. Estimated mixed venous P(N2) agreed with values observed during forced dives in a compression chamber used to validate the assumptions of the model. During bouts of foraging dives, estimated mixed venous and tissue P(N2) increased as the bout progressed. Estimated mean maximum mixed venous P(N2) upon return to the surface after a dive was 4.56+/-0.18 atmospheres absolute (ATA; range: 4.37-4.78 ATA). This is equivalent to N2 levels causing a 50% DCS incidence in terrestrial animals of similar mass. Bout termination events were not associated with extreme mixed venous N2 levels. Fat P(N2) was positively correlated with bout duration and the highest estimated fat P(N2) occurred at the end of a dive bout. The model suggested that short and shallow dives occurring between dive bouts help to reduce supersaturation and thereby DCS risk. Furthermore, adipose tissue could also help reduce DCS risk during the first few dives in a bout by functioning as a sink to buffer extreme levels of N2.

  15. N2O emission hotspots at different spatial scales and governing factors for small scale hotspots

    International Nuclear Information System (INIS)

    Heuvel, R.N. van den; Hefting, M.M.; Tan, N.C.G.; Jetten, M.S.M.; Verhoeven, J.T.A.

    2009-01-01

    Chronically nitrate-loaded riparian buffer zones show high N 2 O emissions. Often, a large part of the N 2 O is emitted from small surface areas, resulting in high spatial variability in these buffer zones. These small surface areas with high N 2 O emissions (hotspots) need to be investigated to generate knowledge on the factors governing N 2 O emissions. In this study the N 2 O emission variability was investigated at different spatial scales. Therefore N 2 O emissions from three 32 m 2 grids were determined in summer and winter. Spatial variation and total emission were determined on three different scales (0.3 m 2 , 0.018 m 2 and 0.0013 m 2 ) at plots with different levels of N 2 O emissions. Spatial variation was high at all scales determined and highest at the smallest scale. To test possible factors inducing small scale hotspots, soil samples were collected for slurry incubation to determine responses to increased electron donor/acceptor availability. Acetate addition did increase N 2 O production, but nitrate addition failed to increase total denitrification or net N 2 O production. N 2 O production was similar in all soil slurries, independent of their origin from high or low emission soils, indicating that environmental conditions (including physical factors like gas diffusion) rather than microbial community composition governed N 2 O emission rates

  16. Novel microelectrode-based online system for monitoring N2O gas emissions during wastewater treatment.

    Science.gov (United States)

    Marques, Ricardo; Oehmen, Adrian; Pijuan, Maite

    2014-11-04

    Clark-type nitrous oxide (N2O) microelectrodes are commonly used for measuring dissolved N2O levels, but have not previously been tested for gas-phase applications, where the N2O emitted from wastewater systems can be directly quantified. In this study, N2O microelectrodes were tested and validated for online gas measurements, and assessed with respect to their temperature, gas flow, composition dependence, gas pressure, and humidity. An exponential correlation between temperature and sensor signal was found, whereas gas flow, composition, pressure, and humidity did not have any influence on the signal. Two of the sensors were tested at different N2O concentration ranges (0-422.3, 0-50, 0-10, and 0-2 ppmv N2O) and exhibited a linear response over each range. The N2O emission dynamics from two laboratory scale sequencing batch reactors performing ammonia or nitrite oxidation were also monitored using one of the microsensors and results were compared with two other analytical methods. Results show that N2O emissions were accurately described with these microelectrodes and support their application for assessing gaseous N2O emissions from wastewater treatment systems. Advantages of the sensors as compared to conventional measurement techniques include a wider quantification range of N2O fluxes, and a single measurement system that can assess both liquid and gas-phase N2O dynamics.

  17. The N2O activation by Rh5 clusters. A quantum chemistry study.

    Science.gov (United States)

    Olvera-Neria, Oscar; Avilés, Roberto; Francisco-Rodríguez, Héctor; Bertin, Virineya; García-Cruz, Raúl; González-Torres, Julio César; Poulain, Enrique

    2015-04-01

    Nitrous oxide (N2O) is a by-product of exhaust pipe gases treatment produced by motor vehicles. Therefore, the N2O reduction to N2 is necessary to meet the actual environmental legislation. The N2O adsorption and dissociation assisted by the square-based pyramidal Rh5 cluster was investigated using the density functional theory and the zero-order regular approximation (ZORA). The Rh5 sextet ground state is the most active in N2O dissociation, though the quartet and octet states are also active because they are degenerate. The Rh5 cluster spontaneously activates the N2─O cleavage, and the reaction is highly exothermic ca. -75 kcal mol(-1). The N2─O breaking is obtained for the geometrical arrangement that maximizes the overlap and electron transfers between the N2O and Rh5 frontier orbitals. The Rh5 high activity is due to the Rh 3d orbitals are located between the N2O HOMO and LUMO orbitals, which makes possible the interactions between them. In particular, the O 2p states strongly interact with Rh 3d orbitals, which finally weaken the N2─O bond. The electron transfer is from the Rh5 HOMO orbital to the N2O antibonding orbital.

  18. 239Pu(n, 2n) and 241Pu(n, 2n) surrogate cross section measurements using NeutronSTARS

    Energy Technology Data Exchange (ETDEWEB)

    Burke, J. T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Alan, B. S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Akindele, O. A. [Univ. of California, Berkeley, CA (United States); Casperson, R. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hughes, R. O. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Koglin, J. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Tamashiro, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Oregon State Univ., Corvallis, OR (United States); Kolos, K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Norman, E. B. [Univ. of California, Berkeley, CA (United States); Saastamoinen, A. [Univ. of California, Los Angeles, CA (United States); Padilla, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Univ. of California, Los Angeles, CA (United States); Fisher, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-12-08

    The goal of this project was to develop a new approach to measuring (n,2n) reactions for isotopes of interest. We set out to measure the 239Pu(n,2n) and 241Pu(n,2n) cross sections by directly detecting the 2n neutrons that are emitted. With the goal of improving the 239Pu(n,2n) cross section and to measure the 241Pu(n,2n) cross section for the first time. To that end, we have constructed a new neutron-charged-particle detector array called NeutronSTARS. It has been described extensively in Casperson et al. [1] and in Akindele et al. [2]. We have used this new neutron-charged-particle array to measure the 241Pu and 239Pu fission neutron multiplicity as a function of equivalent incident-neutron energy from 100 keV to 20 MeV. We have made a preliminary determination of the 239Pu(n,2n) and 241Pu(n,2n) cross sections from the surrogate 240Pu(α,α’2n) and 242Pu(α,α’2n) reactions respectively. The experimental approach, detector array, data analysis, and results to date are summarized in the following sections.

  19. A low temperature investigation of the gas-phase N(2D) + NO reaction. Towards a viable source of N(2D) atoms for kinetic studies in astrochemistry.

    Science.gov (United States)

    Nuñez-Reyes, Dianailys; Hickson, Kevin M

    2018-06-18

    The gas-phase reaction of metastable atomic nitrogen N(2D) with nitric oxide has been investigated over the 296-50 K temperature range using a supersonic flow reactor. As N(2D) could not be produced photolytically in the present work, these excited state atoms were generated instead through the C(3P) + NO → N(2D) + CO reaction while C(3P) atoms were created in situ by the 266 nm pulsed laser photolysis of CBr4 precursor molecules. The kinetics of N(2D) atoms were followed on-resonance by vacuum ultraviolet laser induced fluorescence at 116.7 nm. The measured rate constants for the N(2D) + NO reaction are in excellent agreement with most of the earlier work at room temperature and represent the only available kinetic data for this process below 296 K. The rate constants are seen to increase slightly as the temperature falls to 100 K with a more substantial increase at even lower temperature; a finding which is not reproduced by theoretical work. The prospects for using this chemical source of N(2D) atoms in future studies of a wide range of N(2D) atom reactions are discussed.

  20. N2 Reduction and Hydrogenation to Ammonia by a Molecular Iron-Potassium Complex

    Science.gov (United States)

    Rodriguez, Meghan M.; Bill, Eckhard; Brennessel, William W.; Holland, Patrick L.

    2011-01-01

    The most common catalyst in the Haber-Bosch process for the hydrogenation of dinitrogen (N2) to ammonia is an iron surface promoted with K+, but soluble iron complexes have neither reduced the N-N bond of N2 to nitride nor produced large amounts of NH3 from N2. We report a molecular iron complex that reacts with N2 and a potassium reductant to give a complex with two nitrides, which are bound to iron and potassium cations. The product has a Fe3N2 core, implying that three iron atoms cooperate to break the N-N triple bond through a six-electron reduction. The nitride complex reacts with acid and with H2 to give substantial yields of N2-derived ammonia. These reactions, though not yet catalytic, give structural and spectroscopic insight into N2 cleavage and N-H bond-forming reactions of iron. PMID:22076372

  1. Modeling N2O Reduction and Decomposition in a Circulating Fluidized bed Boiler

    DEFF Research Database (Denmark)

    Johnsson, Jan Erik; Åmand, Lars-Erik; Dam-Johansen, Kim

    1996-01-01

    The N2O concentration was measured in a circulating fluidized bed boiler of commercial size. Kinetics for N2O reduction by char and catalytic reduction and decomposition over bed material from the combustor were determined in a laboratory fixed bed reactor. The destruction rate of N2O in the comb......The N2O concentration was measured in a circulating fluidized bed boiler of commercial size. Kinetics for N2O reduction by char and catalytic reduction and decomposition over bed material from the combustor were determined in a laboratory fixed bed reactor. The destruction rate of N2O...... in the combustion chamber and the cyclone was calculated taking three mechanisms into account: Reduction by char, catalytic decomposition over bed material and thermal decomposition. The calculated destruction rate was in good agreement with the measured destruction of N2O injected at different levels in the boiler...

  2. A consilience model to describe N2O production during biological N removal

    DEFF Research Database (Denmark)

    Domingo Felez, Carlos; Smets, Barth F.

    2016-01-01

    Nitrous oxide (N2O), a potent greenhouse gas, is produced during biological nitrogen conversion in wastewater treatment operations. Complex mechanisms underlie N2O production by autotrophic and heterotrophic organisms, which continue to be unravelled. Mathematical models that describe nitric oxide...... (NO) and N2O dynamics have been proposed. Here, a first comprehensive model that considers all relevant NO and N2O production and consumption mechanisms is proposed. The model describes autotrophic NO production by ammonia oxidizing bacteria associated with ammonia oxidation and with nitrite reduction......, followed by NO reduction to N2O. It also considers NO and N2O as intermediates in heterotrophic denitrification in a 4-step model. Three biological NO and N2O production pathways are accounted for, improving the capabilities of existing models while not increasing their complexity. Abiotic contributions...

  3. Structural and spectral analyses of N,N'-(2,2'-dithiodi-o-phenylene)bis-(furan-2-carboxamide)

    Science.gov (United States)

    Yıldırım, Sema Öztürk; Büyükmumcu, Zeki; Pekdur, Özlem Savaş; Butcher, Ray J.; Doǧan, Şengül Dilem

    2018-02-01

    In this study we report structure determination of N,N'-(2,2'-dithiodi-o-phenylene)bis-(furan-2-carboxamide). 2,2'-Dithiobis(benzamide) derivatives have been reported to possess important biological properties such as antibacterial, antifungal activities and inhibition of blood platelet aggregation and redeterrmined at 100(2)K from the data published by Raftery, Lallbeeharry, Bhowon, Laulloo & Joulea [Acta Cryst. 2009, E65, o16]. 2,2'-Dithiobis(N-butyl-benzamide) has been reported to be useful as an antiseptic for cosmetics. The structural properties of the compound have been characterized by using 1H NMR and the structure were determined by single-crystal X-ray diffraction. Molecular structure crystallizes in triclinic form, space group with a = 9.6396(7) Å, b = 9.9115(7) Å, c = 12.0026(8) Å, α = 109.743(6)°, β = 103.653(6)°, γ = 104.633(6)° and V = 977.15(13) Å3. In the solid state of the molecular structure N-H…S, N-H…O and C-H…O, type interactions provide for stabilization. The geometries of the title compound have been optimized using density functional theory (DFT) method. The calculated values were found to be in agreement with the experimental data.

  4. Synthesis and characterization of N-(2-hydroxy)propyl-3-trimethyl ammonium chitosan chloride for potential application in gene delivery.

    Science.gov (United States)

    Xiao, Bo; Wan, Ying; Wang, Xiaoyu; Zha, Qichen; Liu, Haoming; Qiu, Zhiye; Zhang, Shengmin

    2012-03-01

    A series of N-(2-hydroxy)propyl-3-trimethyl ammonium chitosan chloride (HTCC) samples with various degrees of quaternization ranging from 12.4 to 43.7% was synthesized. The structures and properties of HTCC were investigated by FT-IR, (1)H NMR, conductometric titration and XRD analysis. It was found that HTCC had a more amorphous structure than chitosan. HTCC samples showed significantly lower cytotoxicity than polyethyleneimine in HepG2 and HeLa cell lines. The samples spontaneously formed complexes with pGL3 luciferase plasmid. These complexes had desirable particle sizes (160-300 nm) and zeta potentials (10.8-18.7 mV) when the weight ratios of HTCC to plasmid altered in the range of 3:1-20:1. In vitro gene transfection results indicated that HTCC had significantly high transfection efficiency compared with chitosan for delivering pGL3 luciferase plasmid to HeLa cells. The results suggest that HTCC could be a promising non-viral vector for safe and efficient DNA delivery. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Effect of Soil pH Increase by Biochar on NO, N2O and N2 Production during Denitrification in Acid Soils.

    Directory of Open Access Journals (Sweden)

    Alfred Obia

    Full Text Available Biochar (BC application to soil suppresses emission of nitrous- (N2O and nitric oxide (NO, but the mechanisms are unclear. One of the most prominent features of BC is its alkalizing effect in soils, which may affect denitrification and its product stoichiometry directly or indirectly. We conducted laboratory experiments with anoxic slurries of acid Acrisols from Indonesia and Zambia and two contrasting BCs produced locally from rice husk and cacao shell. Dose-dependent responses of denitrification and gaseous products (NO, N2O and N2 were assessed by high-resolution gas kinetics and related to the alkalizing effect of the BCs. To delineate the pH effect from other BC effects, we removed part of the alkalinity by leaching the BCs with water and acid prior to incubation. Uncharred cacao shell and sodium hydroxide (NaOH were also included in the study. The untreated BCs suppressed N2O and NO and increased N2 production during denitrification, irrespective of the effect on denitrification rate. The extent of N2O and NO suppression was dose-dependent and increased with the alkalizing effect of the two BC types, which was strongest for cacao shell BC. Acid leaching of BC, which decreased its alkalizing effect, reduced or eliminated the ability of BC to suppress N2O and NO net production. Just like untreated BCs, NaOH reduced net production of N2O and NO while increasing that of N2. This confirms the importance of altered soil pH for denitrification product stoichiometry. Addition of uncharred cacao shell stimulated denitrification strongly due to availability of labile carbon but only minor effects on the product stoichiometry of denitrification were found, in accordance with its modest effect on soil pH. Our study indicates that stimulation of denitrification was mainly due to increases in labile carbon whereas change in product stoichiometry was mainly due to a change in soil pH.

  6. The influence of the N(2D) and N(2P) states in the ionization of the pink afterglow of the nitrogen flowing DC discharge

    Science.gov (United States)

    Levaton, J.; Klein, A. N.; Binder, C.

    2018-01-01

    In the present work, we extensively discuss the role of N(2D) and N(2P) atoms in the ionization processes of pink afterglow based on optical emission spectroscopy analysis and kinetic numerical modelling. We studied the pink afterglow generated by a nitrogen DC discharge operating at 0.6 Slm-1 flow rate, 45 mA discharge current and pressures ranging from 250 to 1050 Pa. The 391.4 nm nitrogen band was monitored along the afterglow furnishing the relative density of the N2+(B2Σ+u, v = 0) state. A numerical model developed to calculate the nitrogen species densities in the afterglow fits the excited ion density profiles well for the experimental conditions. From the modelling results, we determine the densities of the N+, N2+, N3+, and N4+ ions; the calculations show that the N3+ ion density predominates in the afterglow at the typical residence times of the pink afterglow. This behaviour has been observed experimentally and reported in the literature. Furthermore, we calculate the fractional contribution in the ionization for several physical-chemical mechanisms in the post-discharge. Even with the N3+ ion density being dominant in the afterglow, we find through the calculations that the ionization is dominated by the reactions N(2D) + N(2P) → N2+(X2Σ+g) + e and N2(a'1Σ-u) + N2(X 1Σg+, v > 24) → N4+ + e. The ion conversion mechanisms, or ion transfer reactions, which are responsible for the fact that the N3+ density dominates in the post-discharge, are investigated.

  7. Controlling cyanobacterial blooms in hypertrophic Lake Taihu, China: will nitrogen reductions cause replacement of non-N2 fixing by N2 fixing taxa?

    Directory of Open Access Journals (Sweden)

    Hans W Paerl

    Full Text Available Excessive anthropogenic nitrogen (N and phosphorus (P inputs have caused an alarming increase in harmful cyanobacterial blooms, threatening sustainability of lakes and reservoirs worldwide. Hypertrophic Lake Taihu, China's third largest freshwater lake, typifies this predicament, with toxic blooms of the non-N2 fixing cyanobacteria Microcystis spp. dominating from spring through fall. Previous studies indicate N and P reductions are needed to reduce bloom magnitude and duration. However, N reductions may encourage replacement of non-N2 fixing with N2 fixing cyanobacteria. This potentially counterproductive scenario was evaluated using replicate, large (1000 L, in-lake mesocosms during summer bloom periods. N+P additions led to maximum phytoplankton production. Phosphorus enrichment, which promoted N limitation, resulted in increases in N2 fixing taxa (Anabaena spp., but it did not lead to significant replacement of non-N2 fixing with N2 fixing cyanobacteria, and N2 fixation rates remained ecologically insignificant. Furthermore, P enrichment failed to increase phytoplankton production relative to controls, indicating that N was the most limiting nutrient throughout this period. We propose that Microcystis spp. and other non-N2 fixing genera can maintain dominance in this shallow, highly turbid, nutrient-enriched lake by outcompeting N2 fixing taxa for existing sources of N and P stored and cycled in the lake. To bring Taihu and other hypertrophic systems below the bloom threshold, both N and P reductions will be needed until the legacy of high N and P loading and sediment nutrient storage in these systems is depleted. At that point, a more exclusive focus on P reductions may be feasible.

  8. DNA oligonucleotide conformations: high resolution NMR studies

    International Nuclear Information System (INIS)

    Mellema, J.-R.

    1984-01-01

    The present work describes a DNA double-helix model, which is well comparable with the models derived from fibre-diffraction studies. The model has a mononucleotide repeat with torsion angles in accordance with average geometries as derived from 1 H NMR studies. Special attention was paid to reduce the number of short H-H nonbonding contacts, which are abundantly present in the 'classical' fibre-diffraction models. Chapter 3 describes the first complete assignment of a 1 H NMR spectrum of a DNA tetramer, d(TAAT). Preliminary conformational data derived from the spectral parameters recorded at 27 0 C are given. A more detailed analysis employing temperature-dependence studies is given in Chapter 4. (Auth.)

  9. Some nitrogen-14 NMR studies in solids

    Energy Technology Data Exchange (ETDEWEB)

    Pratum, T.K.

    1983-11-01

    The first order quadrupolar perturbation of the /sup 14/N NMR spectrum yields information regarding the static and dynamic properties of the surrounding electronic environment. Signal to noise problems caused by long /sup 14/N longitudinal relaxation times (T/sub 1/) and small equilibrium polarizations are reduced by rotating frame cross polarization (CP) experiments between /sup 14/N and /sup 1/H. Using quadrupolar echo and CP techniques, the /sup 14/N quadrupolar coupling constants (e/sup 2/qQ/h) and asymmetry parameters (eta) have been obtained for a variety of tetraalkylammonium compounds by observation of their quadrupolar powder patterns at various temperatures. For choline chloride and iodide the /sup 14/N NMR powder patterns exhibit the effects of anisotropic molecular motion, while choline bromide spectra show no such effects.

  10. Fully automated system for pulsed NMR measurements

    International Nuclear Information System (INIS)

    Cantor, D.M.

    1977-01-01

    A system is described which places many of the complex, tedious operations for pulsed NMR experiments under computer control. It automatically optimizes the experiment parameters of pulse length and phase, and precision, accuracy, and measurement speed are improved. The hardware interface between the computer and the NMR instrument is described. Design features, justification of the choices made between alternative design strategies, and details of the implementation of design goals are presented. Software features common to all the available experiments are discussed. Optimization of pulse lengths and phases is performed via a sequential search technique called Uniplex. Measurements of the spin-lattice and spin-spin relaxation times and of diffusion constants are automatic. Options for expansion of the system are explored along with some of the limitations of the system

  11. Exploring the limits to spatially resolved NMR

    Energy Technology Data Exchange (ETDEWEB)

    Gaedke, Achim; Nestle, Nikolaus [TU Darmstadt, Institute of Condensed Matter Physics (Germany)

    2010-07-01

    Recent advances in MRI have demonstrated resolutions down to 1 {mu}m. Magnetic resonance force microscopy has the potential to reach sensitivity for single nuclear spins. Given these numbers, in vivo imaging of single cells or even biomacromolecules may seem possible. However, for in vivo applications, there are fundamental differences in the contrast mechanisms compared to MRI at macroscopic scales as the length scale of of molecular self-diffusion exceeds that of the spatial resolution on the NMR time scale. Those effects - which are fundamentally different from the echo attenuation in field gradient NMR - even may lead to general limitations on the spatial resolution achievable in aqueous systems with high water content. In our contribution, we explore those effects on a model system in a high-resolution stray-field imaging setup. In addition to experimental results, simulations based on the Bloch-Torrey equation are presented.

  12. Recent topics in NMR imaging and MRI

    International Nuclear Information System (INIS)

    Watanabe, Tokuko

    2002-01-01

    NMR and NMR imaging (MRI) are finding increasing use not only in the clinical and medical fields, but also in material, physicochemical, biological, geological, industrial and environmental applications. This short review is limited to two topics: new techniques and pulse sequences and their application to non-clinical fields that may have clinical application; and new trends in MR contrast agents. The former topic addresses pulse sequence and data analysis; dynamics such as diffusion, flow, velocity and velocimetry; chemometrics; pharmacological agents; and chemotherapy; the latter topic addresses contrast agents (CA) sensitive to biochemical activity; CA based on water exchange; molecular interactions and stability of CA; characteristics of emerging CA; superparamagnetic CA; and macromolecular CA. (author)

  13. Some nitrogen-14 NMR studies in solids

    International Nuclear Information System (INIS)

    Pratum, T.K.

    1983-11-01

    The first order quadrupolar perturbation of the 14 N NMR spectrum yields information regarding the static and dynamic properties of the surrounding electronic environment. Signal to noise problems caused by long 14 N longitudinal relaxation times (T 1 ) and small equilibrium polarizations are reduced by rotating frame cross polarization (CP) experiments between 14 N and 1 H. Using quadrupolar echo and CP techniques, the 14 N quadrupolar coupling constants (e 2 qQ/h) and asymmetry parameters (eta) have been obtained for a variety of tetraalkylammonium compounds by observation of their quadrupolar powder patterns at various temperatures. For choline chloride and iodide the 14 N NMR powder patterns exhibit the effects of anisotropic molecular motion, while choline bromide spectra show no such effects

  14. Investigation of the N2O emission strength in the U. S. Corn Belt

    Science.gov (United States)

    Fu, Congsheng; Lee, Xuhui; Griffis, Timothy J.; Dlugokencky, Edward J.; Andrews, Arlyn E.

    2017-09-01

    Nitrous oxide (N2O) has a high global warming potential and depletes stratospheric ozone. The U. S. Corn Belt plays an important role in the global anthropogenic N2O budget. To date, studies on local surface N2O emissions and the atmospheric N2O budget have commonly used Lagrangian models. In the present study, we used an Eulerian model - Weather Research and Forecasting Chemistry (WRF-Chem) model to investigate the relationships between N2O emissions in the Corn Belt and observed atmospheric N2O mixing ratios. We derived a simple equation to relate the emission strengths to atmospheric N2O mixing ratios, and used the derived equation and hourly atmospheric N2O measurements at the KCMP tall tower in Minnesota to constrain agricultural N2O emissions. The modeled spatial patterns of atmospheric N2O were evaluated against discrete observations at multiple tall towers in the NOAA flask network. After optimization of the surface flux, the model reproduced reasonably well the hourly N2O mixing ratios monitored at the KCMP tower. Agricultural N2O emissions in the EDGAR42 database needed to be scaled up by 19.0 to 28.1 fold to represent the true emissions in the Corn Belt for June 1-20, 2010 - a peak emission period. Optimized mean N2O emissions were 3.00-4.38, 1.52-2.08, 0.61-0.81 and 0.56-0.75 nmol m- 2 s- 1 for June 1-20, August 1-20, October 1-20 and December 1-20, 2010, respectively. The simulated spatial patterns of atmospheric N2O mixing ratios after optimization were in good agreement with the NOAA discrete observations during the strong emission peak in June. Such spatial patterns suggest that the underestimate of emissions using IPCC (Inter-governmental Panel on Climate Change) inventory methodology is not dependent on tower measurement location.

  15. High Resolution Measurements of Nitrous Oxide (N2O in the Elbe Estuary

    Directory of Open Access Journals (Sweden)

    Lisa Brase

    2017-05-01

    Full Text Available Nitrous oxide (N2O is one of the most important greenhouse gases and a major sink for stratospheric ozone. Estuaries are sites of intense biological production and N2O emissions. We aimed to identify hot spots of N2O production and potential pathways contributing to N2O concentrations in the surface water of the tidal Elbe estuary. During two research cruises in April and June 2015, surface water N2O concentrations were measured along the salinity gradient of the Elbe estuary by using a laser-based on-line analyzer coupled to an equilibrator. Based on these high-resolution N2O profiles, N2O saturations, and fluxes across the surface water/atmosphere interface were calculated. Additional measurements of DIN concentrations, oxygen concentration, and salinity were performed. Highest N2O concentrations were determined in the Hamburg port region reaching maximum values of 32.3 nM in April 2015 and 52.2 nM in June 2015. These results identify the Hamburg port region as a significant hot spot of N2O production, where linear correlations of AOU-N2Oxs indicate nitrification as an important contributor to N2O production in the freshwater part. However, in the region with lowest oxygen saturation, sediment denitrification obviously affected water column N2O saturation. The average N2O saturation over the entire estuary was 201% (SD: ±94%, with an average estuarine N2O flux density of 48 μmol m−2 d−1 and an overall emission of 0.18 Gg N2O y−1. In comparison to previous studies, our data indicate that N2O production pathways over the whole estuarine freshwater part have changed from predominant denitrification in the 1980s toward significant production from nitrification in the present estuary. Despite a significant reduction in N2O saturation compared to the 1980s, N2O concentrations nowadays remain on a high level, comparable to the mid-90s, although a steady decrease of DIN inputs occurred over the last decades. Hence, the Elbe estuary still

  16. NMR dispersion measurement of dynamic nuclear polarization

    International Nuclear Information System (INIS)

    Davies, K.; Cox, S.F.J.

    1978-01-01

    The feasibility of monitoring dynamic nuclear polarization from the NMR dispersive susceptibility is examined. Two prototype instruments are tested in a polarized proton target using organic target material. The more promising employs a tunnel diode oscillator, inside the target cavity, and should provide a precise polarization measurement working at a frequency far enough from the main resonance for the disturbance of the measured polarization to be negligible. Other existing methods for measuring target polarization are briefly reviewed. (author)

  17. Structure of high-resolution NMR spectra

    CERN Document Server

    Corio, PL

    2012-01-01

    Structure of High-Resolution NMR Spectra provides the principles, theories, and mathematical and physical concepts of high-resolution nuclear magnetic resonance spectra.The book presents the elementary theory of magnetic resonance; the quantum mechanical theory of angular momentum; the general theory of steady state spectra; and multiple quantum transitions, double resonance and spin echo experiments.Physicists, chemists, and researchers will find the book a valuable reference text.

  18. NMR of 1,2-dioxiquinolines

    International Nuclear Information System (INIS)

    Figueroa Villar, Jose Daniel; Santos, N.L. dos

    1993-01-01

    Several derivates of quinoline are known for presenting pharmacological activity as antibiotics and anti-parasites, from which an important group are the antibiotics for the treatment of malaria and infections of the urinary tract. This work presents the structures and the NMR spectra of three new derivates of quinoline. These compounds are being tested as possible antibiotics for the treatment of urinary infections caused by Escherichia coli which are extremely resistant to other types of antibiotics

  19. 31-P NMR spectroscopy in radiotherapy

    International Nuclear Information System (INIS)

    Kiricuta, I.C.; Schmitt, W.G.H.; Beyer, H.K.

    1987-01-01

    Results suggest 31-P NMR spectroscopy to allow a discrimination between good and bad blood supply to the tumour owing to different metabolic behaviour and to furnish important information on tumour response to radiotherapy just a few hours after the application of a relatively low dose. Spectroscopy showed the radiation-sensitive tumour cells to behave relatively uniformly after radiotherapy suggesting this behaviour to be interpreted as therapeutical effectiveness. (orig./SHA) [de

  20. 3D Reconstruction of NMR Images

    Directory of Open Access Journals (Sweden)

    Peter Izak

    2007-01-01

    Full Text Available This paper introduces experiment of 3D reconstruction NMR images scanned from magnetic resonance device. There are described methods which can be used for 3D reconstruction magnetic resonance images in biomedical application. The main idea is based on marching cubes algorithm. For this task was chosen sophistication method by program Vision Assistant, which is a part of program LabVIEW.

  1. Characterization of functional polymers by NMR

    International Nuclear Information System (INIS)

    Neto, Oscar H.S. A.S.; San Gil, Rosane A.S.; Nakayama, T.; Costa Neto, Claudio

    1993-01-01

    Several synthetic polymers are used in the chemical analysis of complexes mixtures aiming to extract certain specific functional groups for further identification. This work describes the utilization of NMR in the characterization of one of the above mentioned compounds which will be used as reagent for the synthesis of another compound of the same type, which will be further used in the chemical analysis of alcohols and phenols. The methodology is described. The results are described and discussed

  2. NMR characteristics of rat mammary tumors

    International Nuclear Information System (INIS)

    Osbakken, M.; Kreider, J.; Taczanowsky, P.

    1984-01-01

    12 rats were injected intradermally with 13762A rat mammary adenocarcinoma (1 x 10/sup 6/ cells). 3 rats died before completion of the study and 2 rat had tumor regression; the first 3 were excluded from data analysis. NMR imaging with a 1.5K gauss resistive magnet at 2, 3, 4, and 5 weeks after injection demonstrated increasing tumor mass. Saturation recovery (SR), inversion recovery (IR), and spin echo (SE) pulse sequence images and T/sub 1/ calculation were done for tumor characterization. (Tumor size was too small to identify at 2 weeks.) 3 rats were sacrificed after the last 3 imaging periods for histological studies, done to distinguish solid tumor mass from necrosis. Planimetry of tumor areas showed that as tumors grew in size, the ratio of necrotic area to area of solid tumor increased (week 3 = .3 +- .11; week 4 = .45 +- .07; week 5 = .51 +- 05); simultaneous calculated T/sub 1/ values also increased (week 3 = .35 +- .15; week 4 = .45 +- .06; week 5 = .42 +- 03). Qualitative NMR image T/sub 1/ values also increased as evidenced by progression of SR and IR tumor image intensity from very bright compared to the rest of the body at week 3 to less intense than other structures at week 5. These findings indicate that change in T/sub 1/ may be secondary to the pathophysiological change in the tumor (the increasing in necrosis, associated with increased free water). Thus, the range of T/sub 1/ values obtained in tumors in this study (and in previous studies) may be due to change in tumor physiology and anatomy. Careful correlation of histological with NMR data may allow ultimate use of NMR relaxation characteristics for determination of the physiological state of tumors

  3. Evaluation and adjustment of description of denitrification in the DailyDayCent and COUP models based on N2 and N2O laboratory incubation system measurements

    Science.gov (United States)

    Grosz, Balázs; Well, Reinhard; Dannenmann, Michael; Dechow, René; Kitzler, Barbara; Michel, Kerstin; Reent Köster, Jan

    2017-04-01

    Denitrification is an anaerobic key process by microbes where the NO3- is step-by-step reduced and emitted as NO, N2O and finally N2 gas from the soil. The accurate knowledge of the reduction of nitrate (NO3-) and nitrite (NO2-) to N2O and molecular N2 is important because the N2O fraction is further reduced to N2 and constitutes the main emission source of this greenhouse gas from agricultural soils. Hence, our understanding and ability to quantify soil denitrification is crucial for mitigating nitrogen fertilizer loss as well as for reducing N2O emissions. Models can be an important tool to predict mitigation effects and help to develop climate smart mitigation strategies. Ideally, commonly used biogeochemical models could provide adequate predictions of denitrification processes of agricultural soils but often simplified process descriptions and inadequate model parameters prevent models from simulating adequate fluxes of N2 and N2O on field scale. Model development and parametrization often suffers from limited availability of empirical data describing denitrification processes in agricultural soils. While in many studies N2O emissions are used to develop and train models, detailed measurements on NO, N2O, N2 fluxes and concentrations and related soil conditions are necessary to develop and test adequate model algorithms. Composition of denitrifying communities, coinciding effects of management and local conditions on the development of denitrification hotspots are highly variable in space and time. To address this issue the coordinated research unit „Denitrification in Agricultural Soils: Integrated Control and Modelling at Various Scales (DASIM)" was initiated to more closely investigate N-fluxes caused by denitrification in response to environmental effects, soil properties and microbial communities. Data suitable to validate denitrification models are still scarce due to previous technical and/or methodical limitations of measuring N2 fluxes, but large

  4. 43Ca NMR in solid state

    Science.gov (United States)

    Bellot, P.-V.; Trokiner, A.; Zhdanov, Yu.; Yakubovskii, A.

    1998-02-01

    In this paper we show that 43Ca is a suitable NMR probe to study the properties of high-Tc superconducting oxides. In the normal state, we report the temperature and doping dependencies of the spin susceptibility measured by 43Ca NMR. In the superconducting state and more exactly in the mixed state, by analysing 43Ca NMR linewidth, we have studied the magnetic induction distribution due to the presence of vortices and deduced λ, the penetration depth. Dans cet article, on montre que l'isotope 43 du calcium est une bonne sonde RMN pour l'étude des propriétés des oxydes supraconducteurs à haute température. Dans l'état normal, par la détermination du déplacement de la raie, en fonction de la température, on accède à la variation thermique de la susceptibilité de spin. Dans l'état supraconducteur et plus particulièrement dans l'état mixte, la largeur de raie RMN permet d'étudier la distribution d'induction magnétique due à la présence des vortex et de déterminer λ, la longueur de pénétration.

  5. Automatic maximum entropy spectral reconstruction in NMR

    International Nuclear Information System (INIS)

    Mobli, Mehdi; Maciejewski, Mark W.; Gryk, Michael R.; Hoch, Jeffrey C.

    2007-01-01

    Developments in superconducting magnets, cryogenic probes, isotope labeling strategies, and sophisticated pulse sequences together have enabled the application, in principle, of high-resolution NMR spectroscopy to biomolecular systems approaching 1 megadalton. In practice, however, conventional approaches to NMR that utilize the fast Fourier transform, which require data collected at uniform time intervals, result in prohibitively lengthy data collection times in order to achieve the full resolution afforded by high field magnets. A variety of approaches that involve nonuniform sampling have been proposed, each utilizing a non-Fourier method of spectrum analysis. A very general non-Fourier method that is capable of utilizing data collected using any of the proposed nonuniform sampling strategies is maximum entropy reconstruction. A limiting factor in the adoption of maximum entropy reconstruction in NMR has been the need to specify non-intuitive parameters. Here we describe a fully automated system for maximum entropy reconstruction that requires no user-specified parameters. A web-accessible script generator provides the user interface to the system

  6. Phosphorus NMR of isolated perfused morris hepatomas

    International Nuclear Information System (INIS)

    Graham, R.A.; Meyer, R.A.; Brown, T.R.; Sauer, L.A.

    1986-01-01

    The authors are developing techniques for the study of perfused solid tumors by NMR. Tissue-isolated solid hepatomas were grown to 1-2 cm diameter as described previously. The arterial supply was isolated and the tumors perfused (0.5 - 1.0 ml/min) in vitro at 25 C with a 15% suspension of red blood cells in Krebs-Henseliet solution. 31 P-NMR spectra were acquired at 162 MHz in a specially-designed NMR probe using a solenoidal coil. Intracellular pH (monitored from the chemical shift of inorganic phosphate) and ATP levels were stable for up to 6 hrs during perfusion. During 30 min of global ischemia, ATP decreased by 75% and pH fell from 7.0 to 6.7. These changes were reversed by 1 hr reperfusion. In addition to ATP and phosphate, the spectra included a large resonance due to phosphomonoesters, as well as peaks consistent with glycerylphosphocholine, glyceryl-phosphoethanolamine, phosphocreatine, NAD, and UDPG. However, the most novel feature of the spectra was the presence of an unidentified peak in the phosphonate region (+ 16.9 ppm). The peak was not present in spectra of muscle, liver, brain, kidney, or fat tissues excised from the same animals. They are presently attempting to identify the compound that gives rise to this peak and to establish its metabolic origin

  7. Solid state NMR study of cumbaru flour

    International Nuclear Information System (INIS)

    Nogueira, Jose S.; Bathista, Andre L.B.S.; Silva, Emerson O.; Priante Filho, Nicolau; Tavares, Maria I.B.

    2001-01-01

    The polysaccharide obtained by seed of Dipteryx alata Vog, has been characterised by 13 C solid state, using the basic routine techniques, like MAS and CPMAS and by the proton spin-lattice relaxation time in the rotating frame parameter (T 1 H ρ). Knowing that the chemical structure and molecular dynamic are extremely necessary route to obtain information on the polysaccharides, this work contributes to the classification of the seed containing in the cumbaru fruit to get response on its application. To obtain the initial responses for our purposes some solid state NMR techniques were chosen. The CPMAS 13 C NMR spectrum of the polysaccharide was investigated to know if it has some crystallinity. The MAS 13 C NMR spectrum showed the presence of domains with distinct molecular mobility, because these domains will differ basically in the distribution size and chain packing. The variable contact time experiment was used to analyse the distribution form of 13 C decays, which give us more information about sample heterogeneity. The T 1 H ρHr values were obtained from the variable contact time and by delayed contact time experiment, because these parameter indicate the order of polysaccharides. From the values of this parameter, we found that this polysaccharide is completely non-ordered. (author)

  8. NMR measurement of bitumen at different temperatures.

    Science.gov (United States)

    Yang, Zheng; Hirasaki, George J

    2008-06-01

    Heavy oil (bitumen) is characterized by its high viscosity and density, which is a major obstacle to both well logging and recovery. Due to the lost information of T2 relaxation time shorter than echo spacing (TE) and interference of water signal, estimation of heavy oil properties from NMR T2 measurements is usually problematic. In this work, a new method has been developed to overcome the echo spacing restriction of NMR spectrometer during the application to heavy oil (bitumen). A FID measurement supplemented the start of CPMG. Constrained by its initial magnetization (M0) estimated from the FID and assuming log normal distribution for bitumen, the corrected T2 relaxation time of bitumen sample can be obtained from the interpretation of CPMG data. This new method successfully overcomes the TE restriction of the NMR spectrometer and is nearly independent on the TE applied in the measurement. This method was applied to the measurement at elevated temperatures (8-90 degrees C). Due to the significant signal-loss within the dead time of FID, the directly extrapolated M0 of bitumen at relatively lower temperatures (viscosity, the extrapolated M0 of bitumen at over 60 degrees C can be reasonably assumed to be the real value. In this manner, based on the extrapolation at higher temperatures (> or = 60 degrees C), the M0 value of bitumen at lower temperatures (index (HI), fluid content and viscosity were evaluated by using corrected T2.

  9. Rhodopsin-lipid interactions studied by NMR.

    Science.gov (United States)

    Soubias, Olivier; Gawrisch, Klaus

    2013-01-01

    The biophysical properties of the lipid matrix are known to influence function of integral membrane proteins. We report on a sample preparation method for reconstitution of membrane proteins which uses porous anodic aluminum oxide (AAO) filters with 200-nm-wide pores of high density. The substrate permits formation of tubular, single membranes that line the inner surface of pores. One square centimeter of filter with a thickness of 60μm yields on the order of 500cm(2) of solid-supported single bilayer surface, sufficient for NMR studies. The tubular bilayers are free of detergent, fully hydrated, and accessible for ligands from one side of the membrane. The use of AAO filters greatly improves reproducibility of the reconstitution process such that the influence of protein on lipid order parameters can be studied with high resolution. As an example, results for the G protein-coupled receptor of class A, bovine rhodopsin, are shown. By (2)H NMR order parameter measurements, it is detected that rhodopsin insertion elastically deforms membranes near the protein. Furthermore, by (1)H saturation-transfer NMR under conditions of magic angle spinning, we demonstrate detection of preferences in interactions of rhodopsin with particular lipid species. It is assumed that function of integral membrane proteins depends on both protein-induced elastic deformations of the lipid matrix and preferences for interaction of the protein with particular lipid species in the first layer of lipids surrounding the protein. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Principles of high resolution NMR in solids

    CERN Document Server

    Mehring, Michael

    1983-01-01

    The field of Nuclear Magnetic Resonance (NMR) has developed at a fascinating pace during the last decade. It always has been an extremely valuable tool to the organic chemist by supplying molecular "finger print" spectra at the atomic level. Unfortunately the high resolution achievable in liquid solutions could not be obtained in solids and physicists and physical chemists had to live with unresolved lines open to a wealth of curve fitting procedures and a vast amount of speculations. High resolution NMR in solids seemed to be a paradoxon. Broad structure­ less lines are usually encountered when dealing with NMR in solids. Only with the recent advent of mUltiple pulse, magic angle, cross-polarization, two-dimen­ sional and multiple-quantum spectroscopy and other techniques during the last decade it became possible to resolve finer details of nuclear spin interactions in solids. I have felt that graduate students, researchers and others beginning to get involved with these techniques needed a book which trea...

  11. Nuclear magnetic resonance apparatus having semitoroidal RF coil for use in topical NMR and NMR imaging

    International Nuclear Information System (INIS)

    Fukushima, E.; Assink, R.A.; Roeder, S.B.W.; Gibson, A.A.V.

    1984-01-01

    An improved nuclear magnetic resonance (NMR) apparatus for use in topical magnetic resonance (TMR) spectroscopy and other remote sensing NMR applications includes a semitoroidal radio frequency (rf) coil. The semitoroidal rf coil produces an effective alternating magnetic field at a distance from the poles of the coil, to enable NMR measurements to be taken from selected regions inside an object, particularly human and other living subjects. The semitoroidal rf coil is relatively insensitive to magnetic interference from metallic objects located behind the coil, thereby rendering the coil particularly suited for use in both conventional and superconducting NMR magnets. The semitoroidal NMR coil can be constructed so that it emits little or no excess rf electric field associated with the rf magnetic field, thus avoiding adverse effects due to dielectric heating of the sample or to any other electric field interactions. The coil may be combined with a like orthogonal coil and suitably driven to provide a circularly polarised field; or it may be used in conjunction with a concentrically nested smaller semitoroidal coil to move the maximum field further from the coil assembly. (author)

  12. CcpNmr AnalysisAssign: a flexible platform for integrated NMR analysis

    Energy Technology Data Exchange (ETDEWEB)

    Skinner, Simon P.; Fogh, Rasmus H. [University of Leicester, Department of Molecular and Cell Biology, Leicester Institute for Structural- and Chemical Biology (United Kingdom); Boucher, Wayne [University of Cambridge, Department of Biochemistry (United Kingdom); Ragan, Timothy J.; Mureddu, Luca G.; Vuister, Geerten W., E-mail: gv29@le.ac.uk [University of Leicester, Department of Molecular and Cell Biology, Leicester Institute for Structural- and Chemical Biology (United Kingdom)

    2016-10-15

    NMR spectroscopy is an indispensably powerful technique for the analysis of biomolecules under ambient conditions, both for structural- and functional studies. However, in practice the complexity of the technique has often frustrated its application by non-specialists. In this paper, we present CcpNmr version-3, the latest software release from the Collaborative Computational Project for NMR, for all aspects of NMR data analysis, including liquid- and solid-state NMR data. This software has been designed to be simple, functional and flexible, and aims to ensure that routine tasks can be performed in a straightforward manner. We have designed the software according to modern software engineering principles and leveraged the capabilities of modern graphics libraries to simplify a variety of data analysis tasks. We describe the process of backbone assignment as an example of the flexibility and simplicity of implementing workflows, as well as the toolkit used to create the necessary graphics for this workflow. The package can be downloaded from www.ccpn.ac.uk/v3-software/downloads http://www.ccpn.ac.uk/v3-software/downloads and is freely available to all non-profit organisations.

  13. CcpNmr AnalysisAssign: a flexible platform for integrated NMR analysis

    International Nuclear Information System (INIS)

    Skinner, Simon P.; Fogh, Rasmus H.; Boucher, Wayne; Ragan, Timothy J.; Mureddu, Luca G.; Vuister, Geerten W.

    2016-01-01

    NMR spectroscopy is an indispensably powerful technique for the analysis of biomolecules under ambient conditions, both for structural- and functional studies. However, in practice the complexity of the technique has often frustrated its application by non-specialists. In this paper, we present CcpNmr version-3, the latest software release from the Collaborative Computational Project for NMR, for all aspects of NMR data analysis, including liquid- and solid-state NMR data. This software has been designed to be simple, functional and flexible, and aims to ensure that routine tasks can be performed in a straightforward manner. We have designed the software according to modern software engineering principles and leveraged the capabilities of modern graphics libraries to simplify a variety of data analysis tasks. We describe the process of backbone assignment as an example of the flexibility and simplicity of implementing workflows, as well as the toolkit used to create the necessary graphics for this workflow. The package can be downloaded from www.ccpn.ac.uk/v3-software/downloads http://www.ccpn.ac.uk/v3-software/downloads and is freely available to all non-profit organisations.

  14. Guiding automated NMR structure determination using a global optimization metric, the NMR DP score

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yuanpeng Janet, E-mail: yphuang@cabm.rutgers.edu; Mao, Binchen; Xu, Fei; Montelione, Gaetano T., E-mail: gtm@rutgers.edu [Rutgers, The State University of New Jersey, Department of Molecular Biology and Biochemistry, Center for Advanced Biotechnology and Medicine, and Northeast Structural Genomics Consortium (United States)

    2015-08-15

    ASDP is an automated NMR NOE assignment program. It uses a distinct bottom-up topology-constrained network anchoring approach for NOE interpretation, with 2D, 3D and/or 4D NOESY peak lists and resonance assignments as input, and generates unambiguous NOE constraints for iterative structure calculations. ASDP is designed to function interactively with various structure determination programs that use distance restraints to generate molecular models. In the CASD–NMR project, ASDP was tested and further developed using blinded NMR data, including resonance assignments, either raw or manually-curated (refined) NOESY peak list data, and in some cases {sup 15}N–{sup 1}H residual dipolar coupling data. In these blinded tests, in which the reference structure was not available until after structures were generated, the fully-automated ASDP program performed very well on all targets using both the raw and refined NOESY peak list data. Improvements of ASDP relative to its predecessor program for automated NOESY peak assignments, AutoStructure, were driven by challenges provided by these CASD–NMR data. These algorithmic improvements include (1) using a global metric of structural accuracy, the discriminating power score, for guiding model selection during the iterative NOE interpretation process, and (2) identifying incorrect NOESY cross peak assignments caused by errors in the NMR resonance assignment list. These improvements provide a more robust automated NOESY analysis program, ASDP, with the unique capability of being utilized with alternative structure generation and refinement programs including CYANA, CNS, and/or Rosetta.

  15. N2O, NO, N2 and CO2 emissions from tropical savanna and grassland of northern Australia: an incubation experiment with intact soil cores

    Directory of Open Access Journals (Sweden)

    C. Werner

    2014-11-01

    Full Text Available Strong seasonal variability of hygric and thermal soil conditions are a defining environmental feature in northern Australia. However, how such changes affect the soil–atmosphere exchange of nitrous oxide (N2O, nitric oxide (NO and dinitrogen (N2 is still not well explored. By incubating intact soil cores from four sites (three savanna, one pasture under controlled soil temperatures (ST and soil moisture (SM we investigated the release of the trace gas fluxes of N2O, NO and carbon dioxide (CO2. Furthermore, the release of N2 due to denitrification was measured using the helium gas flow soil core technique. Under dry pre-incubation conditions NO and N2O emissions were very low (−2 h−1; 2O-N m−2 h−1 or in the case of N2O, even a net soil uptake was observed. Substantial NO (max: 306.5 μg N m−2 h−1 and relatively small N2O pulse emissions (max: 5.8 ± 5.0 μg N m−2 h−1 were recorded following soil wetting, but these pulses were short lived, lasting only up to 3 days. The total atmospheric loss of nitrogen was generally dominated by N2 emissions (82.4–99.3% of total N lost, although NO emissions contributed almost 43.2% to the total atmospheric nitrogen loss at 50% SM and 30 °C ST incubation settings (the contribution of N2 at these soil conditions was only 53.2%. N2O emissions were systematically higher for 3 of 12 sample locations, which indicates substantial spatial variability at site level, but on average soils acted as weak N2O sources or even sinks. By using a conservative upscale approach we estimate total annual emissions from savanna soils to average 0.12 kg N ha−1 yr−1 (N2O, 0.68 kg N ha−1 yr−1 (NO and 6.65 kg N ha−1 yr−1 (N2. The analysis of long-term SM and ST records makes it clear that extreme soil saturation that can lead to high N2O and N2 emissions only occurs a few days per year and thus has little impact on the annual total. The potential contribution of nitrogen released due to pulse events

  16. Aircraft Observations of Nitrous Oxide (N2O) in the San Joaquin Valley of California

    Science.gov (United States)

    Muto, S.; Herrera, S.; Pusede, S.

    2017-12-01

    Agriculture is the largest source of anthropogenic nitrous oxide (N2O) in the U.S. While it is generally known which processes produce N2O, there is considerable uncertainty in controls over N2O emissions. Factors that determine N2O fluxes, such as soil properties and manure management, are highly variable in space and time, and, as a result, it has proven difficult to upscale chamber-derived soil flux measurements to regional spatial scales. Aircraft observations provide a regional picture of the N2O spatial distribution, but, because N2O is very long-lived, it is challenging to attribute measured concentrations of N2O to distinct local sources, especially over areas with complex and integrated land use. This study takes advantage of a novel aircraft N2O dataset collected onboard the low-flying, slow-moving NASA C-23 Sherpa in the San Joaquin Valley (SJV) of California, a region with a variety of N2O sources, including dairies, feedlots, fertilized cropland, and industrial facilities. With these measurements, we link observed N2O enhancements to specific sources at sub-inventory spatial scales. We compare our results with area-weighted emission profiles obtained by integrating detailed emission inventory data, agricultural statistics, and GIS source mapping.

  17. Archaea produce lower yields of N2 O than bacteria during aerobic ammonia oxidation in soil.

    Science.gov (United States)

    Hink, Linda; Nicol, Graeme W; Prosser, James I

    2017-12-01

    Nitrogen fertilisation of agricultural soil contributes significantly to emissions of the potent greenhouse gas nitrous oxide (N 2 O), which is generated during denitrification and, in oxic soils, mainly by ammonia oxidisers. Although laboratory cultures of ammonia oxidising bacteria (AOB) and archaea (AOA) produce N 2 O, their relative activities in soil are unknown. This work tested the hypothesis that AOB dominate ammonia oxidation and N 2 O production under conditions of high inorganic ammonia (NH 3 ) input, but result mainly from the activity of AOA when NH 3 is derived from mineralisation. 1-octyne, a recently discovered inhibitor of AOB, was used to distinguish N 2 O production resulting from archaeal and bacterial ammonia oxidation in soil microcosms, and specifically inhibited AOB growth, activity and N 2 O production. In unamended soils, ammonia oxidation and N 2 O production were lower and resulted mainly from ammonia oxidation by AOA. The AOA N 2 O yield relative to nitrite produced was half that of AOB, likely due to additional enzymatic mechanisms in the latter, but ammonia oxidation and N 2 O production were directly linked in all treatments. Relative contributions of AOA and AOB to N 2 O production, therefore, reflect their respective contributions to ammonia oxidation. These results suggest potential mitigation strategies for N 2 O emissions from fertilised agricultural soils. © 2016 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

  18. Effect of atmosphere on the fabrication of Si2N2O matrix composites

    Directory of Open Access Journals (Sweden)

    Wei Li

    2018-03-01

    Full Text Available Si2N2O matrix composites were fabricated by solid/gas reaction in air or N2 atmosphere. The effects of atmosphere on the phase and microstructure of the composites were investigated. The reaction mechanism of Si2N2O system was discussed by analysing the variation of the Gibbs free energy with temperature. The effect of N2 and air on sintering of Si2N2O matrix composites was discussed in relation to observed kinetics and thermodynamic calculations. The results showed that gradient structure of Si2N2O matrix composites were obtained in N2 atmosphere. While high N2 concentration was useful for the formation of the pure β-Si3N4 ceramics, low N2 concentration was proposed to form the pure Si2N2O ceramics. However, in the air atmosphere, structure of the Si3N4/SiO2 composites is homogeneous without the gradient structure appearing. Its composition is a little different as the O2 concentration changes.

  19. Mechanisms of nitrous oxide (N2 O) formation and reduction in denitrifying biofilms.

    Science.gov (United States)

    Sabba, Fabrizio; Picioreanu, Cristian; Nerenberg, Robert

    2017-12-01

    Nitrous oxide (N 2 O) is a potent greenhouse gas that can be formed in wastewater treatment processes by ammonium oxidizing and denitrifying microorganisms. While N 2 O emissions from suspended growth systems have been extensively studied, and some recent studies have addressed emissions from nitrifying biofilms, much less is known about N 2 O emissions from denitrifying biofilm processes. This research used modeling to evaluate the mechanisms of N 2 O formation and reduction in denitrifying biofilms. The kinetic model included formation and consumption of key denitrification species, including nitrate (NO3-), nitrite (NO2-), nitric oxide (NO), and N 2 O. The model showed that, in presence of excess of electron donor, denitrifying biofilms have two distinct layers of activity: an outer layer where there is net production of N 2 O and an inner layer where there is net consumption. The presence of oxygen (O 2 ) had an important effect on N 2 O emission from suspended growth systems, but a smaller effect on biofilm systems. The effects of NO3- and O 2 differed significantly based on the biofilm thickness. Overall, the effects of biofilm thickness and bulk substrate concentrations on N 2 O emissions are complex and not always intuitive. A key mechanism for denitrifying biofilms is the diffusion of N 2 O and other intermediates from one zone of the biofilm to another. This leads to zones of N 2 O formation or consumption transformations that would not exist in suspended growth systems. © 2017 Wiley Periodicals, Inc.

  20. The first Swedish H1N2 swine influenza virus isolate represents an uncommon reassortant

    Directory of Open Access Journals (Sweden)

    Renström Lena HM

    2009-10-01

    Full Text Available Abstract The European swine influenza viruses (SIVs show considerable diversity comprising different types of H1N1, H3N2, and H1N2 strains. The intensifying full genome sequencing efforts reveal further reassortants within these subtypes. Here we report the identification of an uncommon reassortant variant of H1N2 subtype influenza virus isolated from a pig in a multisite herd where H1N2 swine influenza was diagnosed for the first time in Sweden during the winter of 2008-2009. The majority of the European H1N2 swine influenza viruses described so far possess haemagglutinin (HA of the human-like H1N2 SIV viruses and the neuraminidase (NA of either the European H1N2 or H3N2 SIV-like viruses. The Swedish isolate has an avian-like SIV HA and a H3N2 SIV-like NA, which is phylogenetically more closely related to H3N2 SIV NAs from isolates collected in the early '80s than to the NA of H3N2 origin of the H1N2 viruses isolated during the last decade, as depicted by some German strains, indicative of independent acquisition of the NA genes for these two types of reassortants. The internal genes proved to be entirely of avian-like SIV H1N1 origin. The prevalence of this SIV variant in pig populations needs to be determined, as well as the suitability of the routinely used laboratory reagents to analyze this strain. The description of this H1N2 SIV adds further information to influenza epidemiology and supports the necessity of surveillance for influenza viruses in pigs.

  1. The first Swedish H1N2 swine influenza virus isolate represents an uncommon reassortant.

    Science.gov (United States)

    Bálint, Adám; Metreveli, Giorgi; Widén, Frederik; Zohari, Siamak; Berg, Mikael; Isaksson, Mats; Renström, Lena Hm; Wallgren, Per; Belák, Sándor; Segall, Thomas; Kiss, István

    2009-10-28

    The European swine influenza viruses (SIVs) show considerable diversity comprising different types of H1N1, H3N2, and H1N2 strains. The intensifying full genome sequencing efforts reveal further reassortants within these subtypes. Here we report the identification of an uncommon reassortant variant of H1N2 subtype influenza virus isolated from a pig in a multisite herd where H1N2 swine influenza was diagnosed for the first time in Sweden during the winter of 2008-2009. The majority of the European H1N2 swine influenza viruses described so far possess haemagglutinin (HA) of the human-like H1N2 SIV viruses and the neuraminidase (NA) of either the European H1N2 or H3N2 SIV-like viruses. The Swedish isolate has an avian-like SIV HA and a H3N2 SIV-like NA, which is phylogenetically more closely related to H3N2 SIV NAs from isolates collected in the early '80s than to the NA of H3N2 origin of the H1N2 viruses isolated during the last decade, as depicted by some German strains, indicative of independent acquisition of the NA genes for these two types of reassortants. The internal genes proved to be entirely of avian-like SIV H1N1 origin. The prevalence of this SIV variant in pig populations needs to be determined, as well as the suitability of the routinely used laboratory reagents to analyze this strain.The description of this H1N2 SIV adds further information to influenza epidemiology and supports the necessity of surveillance for influenza viruses in pigs.

  2. The Nitrous Oxide (N2O) Budget: Constraints from Atmospheric Observations and Models

    Science.gov (United States)

    Tian, H.; Thompson, R.; Canadell, J.; Winiwarter, W.; Tian, H.; Thompson, R.; Prather, M. J.

    2017-12-01

    The increasing global abundance of N2O poses a threat to human health and society over this coming century through both climate change and ozone depletion. In the sense of greenhouse gases, N2O ranks third behind CO2 and CH4. In the sense of ozone depletion, N2O stands alone. In order to identify the cause of these increases and hopefully reverse them, we need to have a thorough understanding of the sources and sinks (a.k.a. the budget) of N2O and how they can be altered. A bottom-up approach to the budget evaluates individual biogeochemical sources of N2O from the land and ocean; whereas, a top-down approach uses atmospheric observations of the variability, combined with modeling of the atmospheric chemistry and transport, to infer the magnitude of sources and sinks throughout the Earth system. This paper reviews top-down approaches using atmospheric data; a similar top-down approach can be taken with oceanic measurements of N2O, but is not covered here. Stratospheric chemistry is the predominant loss of N2O, and here we review how a merging of new measurements with stratospheric chemistry models is able to provide a constrained budget for the global N2O sink. N2O surface sources are transported and mixed throughout the atmosphere, providing positive anomalies in the N2O abundance (mole fraction of N2O with respect to dry air); while N2O-depleted air from the stratosphere provides negative anomalies. With accurate atmospheric transport models, including for stratosphere-troposphere exchange, the observed tropospheric variability in N2O is effectively a fingerprint of the location and magnitude of sources. This inverse modeling of sources is part of the top-down constraints and is reviewed here.

  3. N2O production pathways in the subtropical acid forest soils in China

    International Nuclear Information System (INIS)

    Zhang Jinbo; Cai Zucong; Zhu Tongbin

    2011-01-01

    To date, N 2 O production pathways are poorly understood in the humid subtropical and tropical forest soils. A 15 N-tracing experiment was carried out under controlled laboratory conditions to investigate the processes responsible for N 2 O production in four subtropical acid forest soils (pH 2 O emission in the subtropical acid forest soils, being responsible for 56.1%, 53.5%, 54.4%, and 55.2% of N 2 O production, in the GC, GS, GB, and TC soils, respectively, under aerobic conditions (40%-52%WFPS). The heterotrophic nitrification (recalcitrant organic N oxidation) accounted for 27.3%-41.8% of N 2 O production, while the contribution of autotrophic nitrification was little in the studied subtropical acid forest soils. The ratios of N 2 O-N emission from total nitrification (heterotrophic+autotrophic nitrification) were higher than those in most previous references. The soil with the lowest pH and highest organic-C content (GB) had the highest ratio (1.63%), suggesting that soil pH-organic matter interactions may exist and affect N 2 O product ratios from nitrification. The ratio of N 2 O-N emission from heterotrophic nitrification varied from 0.02% to 25.4% due to soil pH and organic matter. Results are valuable in the accurate modeling of N2O production in the subtropical acid forest soils and global budget. - Highlights: → We studied N 2 O production pathways in subtropical acid forest soil under aerobic conditions. → Denitrification was the main source of N 2 O production in subtropical acid forest soils. → Heterotrophic nitrification accounted for 27.3%-41.8% of N 2 O production. → While, contribution of autotrophic nitrification to N 2 O production was little. → Ratios of N 2 O-N emission from nitrification were higher than those in most previous references.

  4. Constraints on global oceanic emissions of N2O from observations and models

    Directory of Open Access Journals (Sweden)

    E. T. Buitenhuis

    2018-04-01

    Full Text Available We estimate the global ocean N2O flux to the atmosphere and its confidence interval using a statistical method based on model perturbation simulations and their fit to a database of ΔpN2O (n =  6136. We evaluate two submodels of N2O production. The first submodel splits N2O production into oxic and hypoxic pathways following previous publications. The second submodel explicitly represents the redox transformations of N that lead to N2O production (nitrification and hypoxic denitrification and N2O consumption (suboxic denitrification, and is presented here for the first time. We perturb both submodels by modifying the key parameters of the N2O cycling pathways (nitrification rates; NH4+ uptake; N2O yields under oxic, hypoxic and suboxic conditions and determine a set of optimal model parameters by minimisation of a cost function against four databases of N cycle observations. Our estimate of the global oceanic N2O flux resulting from this cost function minimisation derived from observed and model ΔpN2O concentrations is 2.4 ± 0.8 and 2.5 ± 0.8 Tg N yr−1 for the two N2O submodels. These estimates suggest that the currently available observational data of surface ΔpN2O constrain the global N2O flux to a narrower range relative to the large range of results presented in the latest IPCC report.

  5. Seroprevalence of H1N1, H3N2 and H1N2 influenza viruses in pigs in seven European countries in 2002-2003

    NARCIS (Netherlands)

    Reeth, K.; Brown, I.H.; Durrwald, R.; Foni, E.; Labarque, G.; Lenihan, P.; Maldonado, J.; Markowska-Daniel, I.; Pensaert, M.; Pospisil, Z.; Koch, G.

    2008-01-01

    Objectives Avian-like H1N1 and human-like H3N2 swine influenza viruses (SIV) have been considered widespread among pigs in Western Europe since the 1980s, and a novel H1N2 reassortant with a human-like H1 emerged in the mid 1990s. This study, which was part of the EC-funded 'European Surveillance

  6. Nqrs Data for C3H2Cl10N2PSb[C3HCl4N2P·Cl6HSb](Subst. No. 0601)

    Science.gov (United States)

    Chihara, H.; Nakamura, N.

    This document is part of Subvolume A `Substances Containing Ag … C10H15' of Volume 48 `Nuclear Quadrupole Resonance Spectroscopy Data' of Landolt-Börnstein - Group III `Condensed Matter'. It contains an extract of Section `3.2 Data tables' of the Chapter `3 Nuclear quadrupole resonance data' providing the NQRS data for C3H2Cl10N2PSb [C3HCl4N2P·Cl6HSb] (Subst. No. 0601)

  7. Formation of N2 in the fixed-bed pyrolysis of low rank coals and the mechanisms; Koteisho netsubunkai ni okeru teitankatan kara no N2 no sisei

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Z.; Otsuka, Y. [Tohoku University, Sendai (Japan). Institute for Chemical Reaction Science

    1996-10-28

    In order to establish coal NOx preventive measures, discussions were given on formation of N2 in the fixed-bed pyrolysis of low rank coals and the mechanisms thereof. Chinese ZN coal and German RB coal were used for the discussions. Both coals do not produce N2 at 600{degree}C, and the main product is volatile nitrogen. Conversion into N2 does not depend on heating rates, but increases linearly with increasing temperature, and reaches 65% to 70% at 1200{degree}C. In contrast, char nitrogen decreases linearly with the temperature. More specifically, these phenomena suggest that the char nitrogen or its precursor is the major supply source of N2. When mineral substances are removed by using hydrochloric acid, their catalytic action is lost, and conversion into N2 decreases remarkably. Iron existing in ion-exchanged condition in low-rank coal is reduced and finely diffused into metallic iron particles. The particles react with heterocyclic nitrogen compounds and turn into iron nitride. A solid phase reaction mechanism may be conceived, in which N2 is produced due to decomposition of the iron nitride. 5 refs., 4 figs., 1 tab.

  8. Quantification of nitrous oxide (N2O) emissions and soluble microbial product (SMP) production by a modified AOB-NOB-N2O-SMP model.

    Science.gov (United States)

    Kim, MinJeong; Wu, Guangxue; Yoo, ChangKyoo

    2017-03-01

    A modified AOB-NOB-N 2 O-SMP model able to quantify nitrous oxide (N 2 O) emissions and soluble microbial product (SMP) production during wastewater treatment is proposed. The modified AOB-NOB-N 2 O-SMP model takes into account: (1) two-step nitrification by ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB), (2) N 2 O production by AOB denitrification under oxygen-limited conditions and (3) SMP production by microbial growth and endogenous respiration. Validity of the modified model is demonstrated by comparing the simulation results with experimental data from lab-scale sequencing batch reactors (SBRs). To reliably implement the modified model, a model calibration that adjusts model parameters to fit the model outputs to the experimental data is conducted. The results of this study showed that the modeling accuracy of the modified AOB-NOB-N 2 O-SMP model increases by 19.7% (NH 4 ), 51.0% (NO 2 ), 57.8% (N 2 O) and 16.7% (SMP) compared to the conventional model which does not consider the two-step nitrification and SMP production by microbial endogenous respiration. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Investigation of nitrous oxide (N2O) abatement technologies. 2; Asanka chisso (N2O) no teigen taisaku ni kansuru chosa. 2

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    Emission amount of nitrous oxide (N2O) from anthropogenic sources is analyzed, and reduction effects by the abatement technologies are evaluated. The concentration of nitrous oxide in the atmosphere continues to increase and emissions from agricultural and ecosystem sources are drawing particular attention. For the emission of N2O in Japan, 8.28 Gg-N2O per year is emitted from fossil fuel combustion facilities, 6.95 from waste incineration facilities, 22.5 from transportation vehicles including automobiles, 26.7 from the chemical industry including establishments engaged in adipic acid production, 2.1 from sewage treatment facilities including septic tanks, 6.3 from farmland, and 7.1 from livestock excrement. For the N2O abatement technologies for different sources, fuel improvement, high temperature combustion, acceleration of reduction decomposition reaction, and development of catalysts are significant for the combustion technologies. In connection with N2O discharged in the process of adipic acid production, major businesses have internationally committed to up to 99% abatement of the N2O emissions by 1998. With regard to wastewater and sewage treatment facilities and septic tanks, improvement in COD/NO-N ratio, retention period, pH level, and reduction process is pointed out. 204 refs., 70 figs., 53 tabs.

  10. NMDA receptor GluN2A/GluN2B subunit ratio as synaptic trait of levodopa-induced dyskinesias: from experimental models to patients

    Directory of Open Access Journals (Sweden)

    Manuela eMellone

    2015-07-01

    Full Text Available Levodopa-induced dyskinesias (LIDs are major complications in the pharmacological management of Parkinson’s disease (PD. Abnormal glutamatergic transmission in the striatum is considered a key factor in the development of LIDs. This work aims at i. characterizing NMDA receptor GluN2A/GluN2B subunit ratio as a common synaptic trait in rat and primate models of LIDs and in dyskinetic PD patients, and ii. validating the potential therapeutic effect of a cell-permeable peptide interfering with GluN2A synaptic localization on the dyskinetic behavior of these experimental models of LIDs. Here we demonstrate an altered ratio of synaptic GluN2A/GluN2B-containing NMDA receptors in the striatum of levodopa-treated dyskinetic rats and monkeys as well as in post-mortem tissue from dyskinetic PD patients. The modulation of synaptic NMDA receptor composition by a cell-permeable peptide interfering with GluN2A subunit interaction with the scaffolding protein PSD-95 leads to a reduction in the dyskinetic motor behavior in the two animal models of LIDs. Our results indicate that targeting synaptic NMDA receptor subunit composition may represent an intriguing therapeutic approach aimed at ameliorating levodopa motor side effects.

  11. Screening the DNA interaction ability and antimicrobial activity of a few novel bioactive complexes tethering N-((2-aminophenyl)(phenyl)methylene)-4-nitroaniline

    Energy Technology Data Exchange (ETDEWEB)

    Muniyandi, Vellaichamy; Raman, Natarajan, E-mail: ramchem1964@gmail.com

    2016-11-01

    Few novel transition metal complexes having N-((2-aminophenyl)(phenyl)methylene)-4-nitroaniline were synthesized and characterized by elemental analyses, IR, {sup 1}H and {sup 13}C NMR, electronic, EPR and mass spectra, conductivity and magnetic susceptibility measurements. All the metal complexes adopted square planar geometrical arrangements. The DNA-binding properties of the metal(II) complexes have been investigated by electronic absorption, fluorescence, CD spectra, cyclic voltammetry, differential pulse voltammogram and viscosity measurements. The results obtained indicate that these complexes bind to DNA via an intercalation binding mode. DNA cleavage activities indicate that the metal complexes exhibit greater activity than the ligand. The antimicrobial screening reveals that all the metal complexes exhibit better activity than the free ligand. - Highlights: • The newly synthesized mixed-ligand metal complexes act as persistent intercalators. • These mixed-ligand metal complexes display better chemical nuclease activity. • They exhibit potential antimicrobial activity. • Novel DNA targeting metal complexes are synthesized.

  12. N2O, NO, N2 and CO2 emissions from tropical savanna and grassland of northern Australia: an incubation experiment with intact soil cores

    Science.gov (United States)

    Werner, C.; Reiser, K.; Dannenmann, M.; Hutley, L. B.; Jacobeit, J.; Butterbach-Bahl, K.

    2014-11-01

    Strong seasonal variability of hygric and thermal soil conditions are a defining environmental feature in northern Australia. However, how such changes affect the soil-atmosphere exchange of nitrous oxide (N2O), nitric oxide (NO) and dinitrogen (N2) is still not well explored. By incubating intact soil cores from four sites (three savanna, one pasture) under controlled soil temperatures (ST) and soil moisture (SM) we investigated the release of the trace gas fluxes of N2O, NO and carbon dioxide (CO2). Furthermore, the release of N2 due to denitrification was measured using the helium gas flow soil core technique. Under dry pre-incubation conditions NO and N2O emissions were very low (soil uptake was observed. Substantial NO (max: 306.5 μg N m-2 h-1) and relatively small N2O pulse emissions (max: 5.8 ± 5.0 μg N m-2 h-1) were recorded following soil wetting, but these pulses were short lived, lasting only up to 3 days. The total atmospheric loss of nitrogen was generally dominated by N2 emissions (82.4-99.3% of total N lost), although NO emissions contributed almost 43.2% to the total atmospheric nitrogen loss at 50% SM and 30 °C ST incubation settings (the contribution of N2 at these soil conditions was only 53.2%). N2O emissions were systematically higher for 3 of 12 sample locations, which indicates substantial spatial variability at site level, but on average soils acted as weak N2O sources or even sinks. By using a conservative upscale approach we estimate total annual emissions from savanna soils to average 0.12 kg N ha-1 yr-1 (N2O), 0.68 kg N ha-1 yr-1 (NO) and 6.65 kg N ha-1 yr-1 (N2). The analysis of long-term SM and ST records makes it clear that extreme soil saturation that can lead to high N2O and N2 emissions only occurs a few days per year and thus has little impact on the annual total. The potential contribution of nitrogen released due to pulse events compared to the total annual emissions was found to be of importance for NO emissions

  13. Knowns and unknowns in metabolomics identified by multidimensional NMR and hybrid MS/NMR methods

    Energy Technology Data Exchange (ETDEWEB)

    Bingol, Kerem; Brüschweiler, Rafael

    2017-02-01

    Metabolomics continues to make rapid progress through the development of new and better methods and their applications to gain insight into the metabolism of a wide range of different biological systems from a systems biology perspective. Customization of NMR databases and search tools allows the faster and more accurate identification of known metabolites, whereas the identification of unknowns, without a need for extensive purification, requires new strategies to integrate NMR with mass spectrometry, cheminformatics, and computational methods. For some applications, the use of covalent and non-covalent attachments in the form of labeled tags or nanoparticles can significantly reduce the complexity of these tasks.

  14. Diagnostic of N2(A) concentration in high velocity nitrogen afterglow at atmospheric pressure

    Science.gov (United States)

    Pointu, Anne-Marie; Mintusov, Evgeny

    2009-10-01

    An optical emission diagnostic was used to measure N2(A) concentration in a high velocity (1000 cm/s) N2 flowing afterglow of corona discharge at atmospheric pressure, used for biological decontamination. Introducing impurities of NO (measured at different axial distances and for different values of NO injected flow. Moreover, it has been demonstrated that N2(A) creation comes from N+N+N2 atom recombination with a global rate around 2e-33 cm^6/s, a result which agrees with literature, as well as N2(A) loss mechanisms were confirmed to go via quenching with O and N atoms. The order of magnitude of obtained N2(A) concentration, about 1e11 cm-3, coincides with the results of direct measurement (by Vegard-Kaplan band), using a spectrometer of better resolution.

  15. BRST cohomology of N = 2 super-Yang-Mills theory in four dimensions

    International Nuclear Information System (INIS)

    Tanzini, A.; Ventura, O.S.; Vilar, L.C.Q.; Sorella, S.P.

    2000-01-01

    The BRST cohomology of the N = 2 supersymmetric Yang-Mills theory in four dimensions is discussed by making use of the twisted version of the N = 2 algebra. By the introduction of a set of suitable constant ghosts associated with the generators of N = 2, the quantization of the model can be done by taking into account both gauge invariance and supersymmetry. In particular, we show how the twisted N = 2 algebra can be used to obtain in a straightforward way the relevant cohomology classes. Moreover, we shall be able to establish a very useful relationship between the local gauge-invariant polynomial tr φ 2 and the complete N = 2 Yang-Mills action. This important relation can be considered as the first step towards a fully algebraic proof of the one-loop exactness of the N = 2 β-function.

  16. [Research advances in control of N2O emission from municipal solid waste landfill sites].

    Science.gov (United States)

    Cai, Chuan-Yu; Li, Bo; Lü, Hao-Hao; Wu, Wei-Xiang

    2012-05-01

    Landfill is one of the main approaches for municipal solid waste treatment, and landfill site is a main emission source of greenhouse gases nitrous oxide (N2O) and methane (CH4). As a high-efficient trace greenhouse gas, N2O has a very high warming potential, with a warming capacity 296 times of CO2, and has a long-term stability in atmosphere, giving greater damage to the ozone layer. Aiming at the researches in the control of N2O emission from municipal solid waste landfill sites, this paper summarized the characteristics and related affecting factors of the N2O emission from the landfill sites, and put forward a series of the measures adaptable to the N2O emission control of present municipal solid waste landfill sites in China. Some further research focuses on the control of N2O emission from the landfill sites were also presented.

  17. Mechanism of plutonium metal dissolution in HNO3-HF-N2H4 solution

    International Nuclear Information System (INIS)

    Karraker, D.G.

    1985-01-01

    An oxidation-reduction balance of the products of the dissolution of plutonium metal and alloys in HNO 3 -HF-N 2 H 4 solution shows that the major reactions during dissolution are the reduction of nitrate to NH 3 , N 2 and N 2 O by the metal, and the oxidation of H free radicals to NH 3 by N 2 H 4 . Reactions between HNO 3 and N 2 H 4 produce varying amounts of HN 3 . The reaction rate is greater for delta-Pu than alpha-Pu, and is increased by higher concentrations of HF and HNO 3 . The low yield of reduced nitrogen species indicates that nitrate is reduced on the metal surface without producing a significant concentration of species that react with N 2 H 4 . It is conjectured that intermediate Pu valences and electron transfer within the metal are involved. 7 refs., 3 tabs

  18. Direct Comparison of 19F qNMR and 1H qNMR by Characterizing Atorvastatin Calcium Content

    Directory of Open Access Journals (Sweden)

    Yang Liu

    2016-01-01

    Full Text Available Quantitative nuclear magnetic resonance (qNMR is a powerful tool in measuring drug content because of its high speed, sensitivity, and precision. Most of the reports were based on proton qNMR (1H qNMR and only a few fluorine qNMR (19F qNMR were reported. No research has been conducted to directly compare the advantage and disadvantage between these two methods. In the present study, both 19F and 1H qNMR were performed to characterize the content of atorvastatin calcium with the same internal standard. Linearity, precision, and results from two methods were compared. Results showed that 19F qNMR has similar precision and sensitivity to 1H qNMR. Both methods generate similar results compared to mass balance method. Major advantage from 19F qNMR is that the analyte signal is with less or no interference from impurities. 19F qNMR is an excellent approach to quantify fluorine-containing analytes.

  19. Structural basis of subunit selectivity for competitive NMDA receptor antagonists with preference for GluN2A over GluN2B subunits

    Energy Technology Data Exchange (ETDEWEB)

    Lind, Genevieve E.; Mou, Tung-Chung; Tamborini, Lucia; Pomper, Martin G.; De Micheli, Carlo; Conti, Paola; Pinto, Andrea; Hansen, Kasper B. (JHU); (Milan); (Montana)

    2017-07-31

    NMDA-type glutamate receptors are ligand-gated ion channels that contribute to excitatory neurotransmission in the central nervous system (CNS). Most NMDA receptors comprise two glycine-binding GluN1 and two glutamate-binding GluN2 subunits (GluN2A–D). We describe highly potent (S)-5-[(R)-2-amino-2-carboxyethyl]-4,5-dihydro-1H-pyrazole-3-carboxylic acid (ACEPC) competitive GluN2 antagonists, of which ST3 has a binding affinity of 52 nM at GluN1/2A and 782 nM at GluN1/2B receptors. This 15-fold preference of ST3 for GluN1/2A over GluN1/2B is improved compared with NVP-AAM077, a widely used GluN2A-selective antagonist, which we show has 11-fold preference for GluN1/2A over GluN1/2B. Crystal structures of the GluN1/2A agonist binding domain (ABD) heterodimer with bound ACEPC antagonists reveal a binding mode in which the ligands occupy a cavity that extends toward the subunit interface between GluN1 and GluN2A ABDs. Mutational analyses show that the GluN2A preference of ST3 is primarily mediated by four nonconserved residues that are not directly contacting the ligand, but positioned within 12 Å of the glutamate binding site. Two of these residues influence the cavity occupied by ST3 in a manner that results in favorable binding to GluN2A, but occludes binding to GluN2B. Thus, we reveal opportunities for the design of subunit-selective competitive NMDA receptor antagonists by identifying a cavity for ligand binding in which variations exist between GluN2A and GluN2B subunits. This structural insight suggests that subunit selectivity of glutamate-site antagonists can be mediated by mechanisms in addition to direct contributions of contact residues to binding affinity.

  20. On electromagnetic duality in locally supersymmetric N = 2 Yang-Mills theory

    CERN Document Server

    Ceresole, Anna; Ferrara, S.; Van Proeyen, Antoine; Ceresole, A; D'Auria, R; Ferrara, S; Van Proeyen, A

    1995-01-01

    We consider duality transformations in N=2 Yang--Mills theory coupled to N=2 supergravity, in a manifestly symplectic and coordinate covariant setting. We give the essential of the geometrical framework which allows one to discuss stringy classical and quantum monodromies, the form of the spectrum of BPS saturated states and the Picard--Fuchs identities encoded in the special geometry of N=2 supergravity theories.

  1. Supersymmetric KP hierarchy in N=1 superspace and its N=2 reductions

    International Nuclear Information System (INIS)

    Lechtenfeld, O.; Sorin, A.

    2000-01-01

    A wide class of N=2 reductions of the supersymmetric KP hierarchy in N=1 superspace is described. This class includes a new N=2 supersymmetric generalization of the Toda chain hierarchy. The Lax pair representations of the bosonic and fermionic flows, local and non-local Hamiltonians, finite and infinite discrete symmetries, first two Hamiltonian structures and the recursion operator of this hierarchy are constructed. Its secondary reduction to new N=2 supersymmetric modified KdV hierarchy is discussed

  2. Supersymmetric KP hierarchy in N=1 superspace and its N=2 reductions

    International Nuclear Information System (INIS)

    Lechtenfeld, O.; Sorin, A.

    1999-01-01

    A wide class of N=2 reductions of the supersymmetric KP hierarchy in N=1 superspace is described. This class includes a new N=2 supersymmetric generalization of the Toda chain hierarchy. The Lax pair representations of the bosonic and fermionic flows, local and nonlocal Hamiltonians, finite and infinite discrete symmetries, first two Hamiltonian structures and the recursion operator of this hierarchy are constructed. Its secondary reduction to new N=2 supersymmetric modified KdV hierarchy is discussed

  3. Replication and transmission of H9N2 influenza viruses in ferrets: evaluation of pandemic potential.

    Directory of Open Access Journals (Sweden)

    Hongquan Wan

    2008-08-01

    Full Text Available H9N2 avian influenza A viruses are endemic in poultry of many Eurasian countries and have caused repeated human infections in Asia since 1998. To evaluate the potential threat of H9N2 viruses to humans, we investigated the replication and transmission efficiency of H9N2 viruses in the ferret model. Five wild-type (WT H9N2 viruses, isolated from different avian species from 1988 through 2003, were tested in vivo and found to replicate in ferrets. However these viruses achieved mild peak viral titers in nasal washes when compared to those observed with a human H3N2 virus. Two of these H9N2 viruses transmitted to direct contact ferrets, however no aerosol transmission was detected in the virus displaying the most efficient direct contact transmission. A leucine (Leu residue at amino acid position 226 in the hemagglutinin (HA receptor-binding site (RBS, responsible for human virus-like receptor specificity, was found to be important for the transmission of the H9N2 viruses in ferrets. In addition, an H9N2 avian-human reassortant virus, which contains the surface glycoprotein genes from an H9N2 virus and the six internal genes of a human H3N2 virus, showed enhanced replication and efficient transmission to direct contacts. Although no aerosol transmission was observed, the virus replicated in multiple respiratory tissues and induced clinical signs similar to those observed with the parental human H3N2 virus. Our results suggest that the establishment and prevalence of H9N2 viruses in poultry pose a significant threat for humans.

  4. Effect of watershed urbanization on N2O emissions from the Chongqing metropolitan river network, China

    Science.gov (United States)

    He, Yixin; Wang, Xiaofeng; Chen, Huai; Yuan, Xingzhong; Wu, Ning; Zhang, Yuewei; Yue, Junsheng; Zhang, Qiaoyong; Diao, Yuanbin; Zhou, Lilei

    2017-12-01

    Watershed urbanization, an integrated anthropogenic perturbation, is another considerable global concern in addition to that of global warming and may significantly enrich the N loadings of watersheds, which then greatly influences the nitrous oxide (N2O) production and fluxes of these aquatic systems. However, little is known about the N2O dynamics in human-dominated metropolitan river networks. In this study, we present the temporal and spatial variations in N2O saturation and emission in the Chongqing metropolitan river network, which is undergoing intensified urbanization. The N2O saturation and fluxes at 84 sampling sites ranged from 126% to 10536% and from 4.5 to 1566.8 μmol N2O m-2 d-1, with means of 1780% and 261 μmol N2O m-2 d-1. The riverine N2O saturation and fluxes increased along with the urbanization gradient and urbanization rate, with disproportionately higher values in urban rivers due to the N2O-rich sewage inputs and enriched in situ N substrates. We found a clear seasonal pattern of N2O saturation, which was co-regulated by both water temperature and precipitation. Regression analysis indicated that the N substrates and dissolved oxygen (DO) that controlled nitrogen metabolism acted as good predictors of the N2O emissions of urban river networks. Particularly, phosphorus (P) and hydromorphological factors (water velocity, river size and bottom substrate) had stronger relationships with the N2O saturation and could also be used to predict the N2O emission hotspots in regions with rapid urbanization. In addition, the default emission factors (EF5-r) used in the Intergovernmental Panel on Climate Change (IPCC) methodology may need revision given the differences among the physical and chemical factors in different rivers, especially urban rivers.

  5. Effects of macro nutrient concentration on biological N2 fixation by Azotobacter vinelandii ATCC 12837

    International Nuclear Information System (INIS)

    Liew Pauline Woan Ying; Nazalan Najimudin; Jong Bor Chyan; Latiffah Noordin; Khairuddin Abdul Rahim; Amir Hamzah Ahmad Ghazali

    2010-01-01

    The dynamic changes of biological N 2 fixation by Azotobacter vinelandii ATCC 12837 under the influence of various macro nutrients, specifically phosphorus (P) and potassium (K), was investigated. In this attempt, Oryza sativa L. var. MR 219 was used as the model plant. Results obtained showed changes in the biological N 2 fixation activities with different macro nutrient(s) manipulations. The research activity enables optimisation of macro nutrients concentration for optimal/ enhanced biological N 2 fixation by A. vinelandii ATCC 12837. (author)

  6. Influenza A Virus with a Human-Like N2 Gene Is Circulating in Pigs

    DEFF Research Database (Denmark)

    Breum, Solvej Østergaard; Hjulsager, Charlotte Kristiane; Trebbien, Ramona

    2013-01-01

    A novel reassortant influenza A virus, H1avN2hu, has been found in Danish swine. The virus contains an H1 gene similar to the hemagglutinin (HA) gene of H1N1 avian-like swine viruses and an N2 gene most closely related to the neuraminidase (NA) gene of human H3N2 viruses from the mid-1990s....

  7. Safety in handling of cryogenic substance (liquid N2) and regulatory aspects

    International Nuclear Information System (INIS)

    Sharma, M.L.

    2009-01-01

    Liquid N 2 is at - 196 deg C may cause cold burning and if being used in a confined area/space upon spill can increase N 2 concentration in the environment and deplete O 2 , hence cause danger to the lives of the occupants if not rescued and evacuated from that area. In view of the this danger/unsafe condition while handling liquid N 2 , safety concerns are discussed in detail

  8. Isotope labeling for NMR studies of macromolecular structure and interactions

    International Nuclear Information System (INIS)

    Wright, P.E.

    1994-01-01

    Implementation of biosynthetic methods for uniform or specific isotope labeling of proteins, coupled with the recent development of powerful heteronuclear multidimensional NMR methods, has led to a dramatic increase in the size and complexity of macromolecular systems that are now amenable to NMR structural analysis. In recent years, a new technology has emerged that combines uniform 13 C, 15 N labeling with heteronuclear multidimensional NMR methods to allow NMR structural studies of systems approaching 25 to 30 kDa in molecular weight. In addition, with the introduction of specific 13 C and 15 N labels into ligands, meaningful NMR studies of complexes of even higher molecular weight have become feasible. These advances usher in a new era in which the earlier, rather stringent molecular weight limitations have been greatly surpassed and NMR can begin to address many central biological problems that involve macromolecular structure, dynamics, and interactions

  9. 13C-NMR assignment, structure, and dynamics of deoxyoligonucleotides

    International Nuclear Information System (INIS)

    Zanatta, N.; Borer, P.N.; Levy, G.C.

    1986-01-01

    The unique spectral properties of 13 C-NMR for studying nucleic acids and some of the important features of 13 C-NMR in oligonucleotide studies are demostrated. The main difficulty in studying oligonucleotides by 13 C-NMR and recent improvements in NMR instrumentation and advances in oligonucleotide synthesis are presented. The high resolution 13 C-NMR spectra, T 1 relaxation times and NOEs were measured for duplex of the self-complementary oligo-DNAs: d(CG) 3 and d(GGTATACC) are studied. The target of this study is to developed a systematic 13 C-NMR spectral assignment and to investigate the structure and dynamics of these two sequences by this techniques. (M.J.C.) [pt

  10. A primer to nutritional metabolomics by NMR spectroscopy and chemometrics

    DEFF Research Database (Denmark)

    Savorani, Francesco; Rasmussen, Morten Arendt; Mikkelsen, Mette Skau

    2013-01-01

    This paper outlines the advantages and disadvantages of using high throughput NMR metabolomics for nutritional studies with emphasis on the workflow and data analytical methods for generation of new knowledge. The paper describes one-by-one the major research activities in the interdisciplinary...... metabolomics platform and highlights the opportunities that NMR spectra can provide in future nutrition studies. Three areas are emphasized: (1) NMR as an unbiased and non-destructive platform for providing an overview of the metabolome under investigation, (2) NMR for providing versatile information and data...... structures for multivariate pattern recognition methods and (3) NMR for providing a unique fingerprint of the lipoprotein status of the subject. For the first time in history, by combining NMR spectroscopy and chemometrics we are able to perform inductive nutritional research as a complement to the deductive...

  11. Isotope labeling for NMR studies of macromolecular structure and interactions

    Energy Technology Data Exchange (ETDEWEB)

    Wright, P.E. [Scripps Research Institute, La Jolla, CA (United States)

    1994-12-01

    Implementation of biosynthetic methods for uniform or specific isotope labeling of proteins, coupled with the recent development of powerful heteronuclear multidimensional NMR methods, has led to a dramatic increase in the size and complexity of macromolecular systems that are now amenable to NMR structural analysis. In recent years, a new technology has emerged that combines uniform {sup 13}C, {sup 15}N labeling with heteronuclear multidimensional NMR methods to allow NMR structural studies of systems approaching 25 to 30 kDa in molecular weight. In addition, with the introduction of specific {sup 13}C and {sup 15}N labels into ligands, meaningful NMR studies of complexes of even higher molecular weight have become feasible. These advances usher in a new era in which the earlier, rather stringent molecular weight limitations have been greatly surpassed and NMR can begin to address many central biological problems that involve macromolecular structure, dynamics, and interactions.

  12. Hotspots of soil N2O emission enhanced through water absorption by plant residue

    Energy Technology Data Exchange (ETDEWEB)

    Kravchenko, A.N.; Toosi, E.R.; Guber, A.K.; Ostrom, N.E.; Yu, J.; Azeem, K.; Rivers, M.L.; Robertson , G.P. (UAF Pakistan); (UC); (Hubei); (MSU)

    2017-06-05

    N2O is a highly potent greenhouse gas and arable soils represent its major anthropogenic source. Field-scale assessments and predictions of soil N2O emission remain uncertain and imprecise due to the episodic and microscale nature of microbial N2O production, most of which occurs within very small discrete soil volumes. Such hotspots of N2O production are often associated with decomposing plant residue. Here we quantify physical and hydrological soil characteristics that lead to strikingly accelerated N2O emissions in plant residue-induced hotspots. Results reveal a mechanism for microscale N2O emissions: water absorption by plant residue that creates unique micro-environmental conditions, markedly different from those of the bulk soil. Moisture levels within plant residue exceeded those of bulk soil by 4–10-fold and led to accelerated N2O production via microbial denitrification. The presence of large (Ø >35 μm) pores was a prerequisite for maximized hotspot N2O production and for subsequent diffusion to the atmosphere. Understanding and modelling hotspot microscale physical and hydrologic characteristics is a promising route to predict N2O emissions and thus to develop effective mitigation strategies and estimate global fluxes in a changing environment.

  13. N2O emission from plant surfaces – light stimulated and a global phenomenon

    DEFF Research Database (Denmark)

    Mikkelsen, Teis Nørgaard; Bruhn, Dan; Ambus, Per

    2017-01-01

    for the first time N2O emission fromterrestrial vegetation in response to natural solar ultra violet radiation. We conducted field site measurementsto investigate N2O atmosphere exchange from grass vegetation exposed to solar irradiance with and withoutUV-screening. Further laboratory tests were conducted...... with a range of species to study the controls and possibleloci of UV-induced N2O emission from plants. Plants released N2O in response to natural sunlight at rates of c.20-50 nmol m-2 h-1, mostly due to the UV component. The emission rate is temperature dependent with a ratherhigh activation energy indicative...

  14. Arbuscular mycorrhizal fungi reduce nitrous oxide emissions from N2 O hotspots.

    Science.gov (United States)

    Storer, Kate; Coggan, Aisha; Ineson, Phil; Hodge, Angela

    2017-12-05

    Nitrous oxide (N 2 O) is a potent, globally important, greenhouse gas, predominantly released from agricultural soils during nitrogen (N) cycling. Arbuscular mycorrhizal fungi (AMF) form a mutualistic symbiosis with two-thirds of land plants, providing phosphorus and/or N in exchange for carbon. As AMF acquire N, it was hypothesized that AMF hyphae may reduce N 2 O production. AMF hyphae were either allowed (AMF) or prevented (nonAMF) access to a compartment containing an organic matter and soil patch in two independent microcosm experiments. Compartment and patch N 2 O production was measured both before and after addition of ammonium and nitrate. In both experiments, N 2 O production decreased when AMF hyphae were present before inorganic N addition. In the presence of AMF hyphae, N 2 O production remained low following ammonium application, but increased in the nonAMF controls. By contrast, negligible N 2 O was produced following nitrate application to either AMF treatment. Thus, the main N 2 O source in this system appeared to be via nitrification, and the production of N 2 O was reduced in the presence of AMF hyphae. It is hypothesized that AMF hyphae may be outcompeting slow-growing nitrifiers for ammonium. This has significant global implications for our understanding of soil N cycling pathways and N 2 O production. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  15. N2 Fluxes From Amazon Cropland Are a Significant Component of Watershed N Budgets.

    Science.gov (United States)

    Fox, R. J.; Neill, C.; Macedo, M.; Davidson, E. A.; Lefebvre, P.; Jankowski, K.; Maracahipes-Santos, L.

    2017-12-01

    Amazon tropical rainforests have experienced significant deforestation and conversion to cropland. Recently, cropping has intensified to include higher application rates of N fertilizer, typically in a soybean-corn rotation. Our previous work in Mato Grosso, Brazil, suggests that the addition of N fertilizer (80 Kg N ha-1 yr-1) has not increased N2O fluxes from soils or elevated dissolved N concentrations in streams or groundwater. Here, we investigate whether N fertilizer is converted to N2 in groundwater. We collected samples during January and October 2016 from streams and well transects across riparian forest buffers bordering cropland or within intact riparian forests. Samples were collected using a positive pressure pump and analyzed using Membrane Inlet Mass Spectrometry (MIMS) for N2, Ar, and O2 and gas chromatography for N2O and CH4. N2 concentrations in excess of solubility (based on Ar) were measured at nearly all locations in January and ranged from -15 to 220 in cropland and -2 to 93 µmol N2-N L-1 in intact forest. N2 concentrations were generally lower in October and ranged from -0.9 to 95 in cropland and -0.6 to 52 µmol N2-N L-1 in intact forest. Higher N2 concentrations accumulated at lower dissolved oxygen concentrations and at the borders between cropland and riparian forest. N2O concentrations were significantly lower than N2 concentrations on both dates and ranged between 0.01 and 0.33 µmol N2O-N L-1. Preliminary estimates suggest that N2 losses from cropland ranged from 10 to 20 kg N ha-1 y-1 and losses from forests ranged from 2 to 12 kg N ha-1 y-1. High concentrations of N2 in groundwater have been found in and around agricultural fields in temperate regions, but direct N2 measurements in tropical agricultural regions have not been previously documented. These results suggest that N2 fluxes from tropical cropland receiving modest amounts of N fertilizer could be substantial.

  16. The first Swedish H1N2 swine influenza virus isolate represents an uncommon reassortant

    OpenAIRE

    Renström Lena HM; Isaksson Mats; Berg Mikael; Zohari Siamak; Widén Frederik; Metreveli Giorgi; Bálint Ádám; Wallgren Per; Belák Sándor; Segall Thomas; Kiss István

    2009-01-01

    Abstract The European swine influenza viruses (SIVs) show considerable diversity comprising different types of H1N1, H3N2, and H1N2 strains. The intensifying full genome sequencing efforts reveal further reassortants within these subtypes. Here we report the identification of an uncommon reassortant variant of H1N2 subtype influenza virus isolated from a pig in a multisite herd where H1N2 swine influenza was diagnosed for the first time in Sweden during the winter of 2008-2009. The majority o...

  17. Two genotypes of H1N2 swine influenza viruses appeared among pigs in China.

    Science.gov (United States)

    Xu, Chuantian; Zhu, Qiyun; Yang, Huanliang; Zhang, Xiumei; Qiao, Chuanling; Chen, Yan; Xin, Xiaoguang; Chen, Hualan

    2009-10-01

    H1N2 is one of the main subtypes of influenza, which circulates in swine all over the world. To investigate the prevalence and genetic of H1N2 in swine of China. Two H1N2 swine influenza viruses were isolated from Tianjin and Guangdong province of China in 2004 and 2006, respectively. The molecular evolution of eight gene segments was analyzed. A/Swine/Tianjin/1/2004 has low identity with A/Swine/Guangdong/2006; in the phylogenetic tree of PA gene, A/Swine/Guangdong/1/2006 and A/Swine/Guangxi/1/2006 along with the H1N2 swine isolates of North America formed a cluster; and A/Swine/Tianjin/2004 and A/Swine/Zhejiang/2004, along with the classical H1N1 swine isolates formed another cluster; except that NA gene of A/Swine/Tianjin/1/2004 fell into the cluster of the H3N2 human influenza virus, indicating the reassortment between H3N2 human and H1N1 swine influenza viruses. Two different genotypes of H1N2 appeared among pigs in China. A/swine/Guangdong/1/06 was probably from H1N2 swine influenza viruses of North America; while A/swine/Tianjin/1/04 maybe come from reassortments of classical H1N1 swine and H3N2 human viruses prevalent in North America.

  18. A reverse genetic analysis of human Influenza A virus H1N2

    OpenAIRE

    Anton, Aline

    2010-01-01

    Reassortment between influenza A viruses of different subtypes rarely appears. Even in a community where H1N1 and H3N2 viruses co-circulate, reassortment to produce persistent viruses of mixed gene segments does not readily occur. H1N2 viruses, that circulated between 2001-2003 were considered to have arisen through the reassortment of the two human influenza subtypes H1N1 and H3N2. Due to the fact they make such a rare appearance, H1N2 viruses used to have new characteristics compared to the...

  19. Novel reassortant of swine influenza H1N2 virus in Germany.

    Science.gov (United States)

    Zell, Roland; Motzke, Susann; Krumbholz, Andi; Wutzler, Peter; Herwig, Volker; Dürrwald, Ralf

    2008-01-01

    European porcine H1N2 influenza viruses arose after multiple reassortment steps involving a porcine influenza virus with avian-influenza-like internal segments and human H1N1 and H3N2 viruses in 1994. In Germany, H1N2 swine influenza viruses first appeared in 2000. Two German H1N2 swine influenza virus strains isolated from pigs with clinical symptoms of influenza are described. They were characterized by the neutralization test, haemagglutination inhibition (HI) test and complete sequencing of the viral genomes. The data demonstrate that these viruses represent a novel H1N2 reassortant. The viruses showed limited neutralization by sera raised against heterologous A/sw/Bakum/1,832/00-like H1N2 viruses. Sera pools from recovered pigs showed a considerably lower HI reaction, indicative of diagnostic difficulties in using the HI test to detect these viruses with A/sw/Bakum/1,832/00-like H1N2 antigens. Genome sequencing revealed the novel combination of the human-like HAH1 gene of European porcine H1N2 influenza viruses and the NAN2 gene of European porcine H3N2 viruses.

  20. Transmission of Avian Influenza Virus (H3N2) to Dogs

    OpenAIRE

    Song, Daesub; Kang, Bokyu; Lee, Chulseung; Jung, Kwonil; Ha, Gunwoo; Kang, Dongseok; Park, Seongjun; Park, Bongkyun; Oh, Jinsik

    2008-01-01

    In South Korea, where avian influenza virus subtypes H3N2, H5N1, H6N1, and H9N2 circulate or have been detected, 3 genetically similar canine influenza virus (H3N2) strains of avian origin (A/canine/Korea/01/2007, A/canine/Korea/02/2007, and A/canine/Korea/03/2007) were isolated from dogs exhibiting severe respiratory disease. To determine whether the novel canine influenza virus of avian origin was transmitted among dogs, we experimentally infected beagles with this influenza virus (H3N2) is...