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Sample records for mas nmr correlation

  1. Spin-echo based diagonal peak suppression in solid-state MAS NMR homonuclear chemical shift correlation spectra

    Science.gov (United States)

    Wang, Kaiyu; Zhang, Zhiyong; Ding, Xiaoyan; Tian, Fang; Huang, Yuqing; Chen, Zhong; Fu, Riqiang

    2018-02-01

    The feasibility of using the spin-echo based diagonal peak suppression method in solid-state MAS NMR homonuclear chemical shift correlation experiments is demonstrated. A complete phase cycling is designed in such a way that in the indirect dimension only the spin diffused signals are evolved, while all signals not involved in polarization transfer are refocused for cancellation. A data processing procedure is further introduced to reconstruct this acquired spectrum into a conventional two-dimensional homonuclear chemical shift correlation spectrum. A uniformly 13C, 15N labeled Fmoc-valine sample and the transmembrane domain of a human protein, LR11 (sorLA), in native Escherichia coli membranes have been used to illustrate the capability of the proposed method in comparison with standard 13C-13C chemical shift correlation experiments.

  2. 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.

  3. 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.

  4. 31P Solid-state MAS NMR spectra

    International Nuclear Information System (INIS)

    Grobet, P.J.; Geerts, H.; Martens, J.A.; Jacobs, P.A.

    1989-01-01

    The structures of the silicoaluminiophosphates MCM-1 and MCM9 were characterized by 27 Al and 31 P MAS NMR. The structural identity of MCM-1 and its silicon-free homologue AlPO 4 -H 3 is demonstrated. The presence of a structural mixture in MCM-9 is confirmed. 31 P MAS NMR spectra of MCM-9 could be interpreted as a superposition of spectra of VPI-5, AlPO 4 -H 3 and SAPO-11 phases. (author). 12 refs.; 3 figs.; 1 tab

  5. Solid state NMR of proteins at high MAS frequencies: symmetry-based mixing and simultaneous acquisition of chemical shift correlation spectra

    International Nuclear Information System (INIS)

    Bellstedt, Peter; Herbst, Christian; Häfner, Sabine; Leppert, Jörg; Görlach, Matthias; Ramachandran, Ramadurai

    2012-01-01

    We have carried out chemical shift correlation experiments with symmetry-based mixing sequences at high MAS frequencies and examined different strategies to simultaneously acquire 3D correlation spectra that are commonly required in the structural studies of proteins. The potential of numerically optimised symmetry-based mixing sequences and the simultaneous recording of chemical shift correlation spectra such as: 3D NCAC and 3D NHH with dual receivers, 3D NC′C and 3D C′NCA with sequential 13 C acquisitions, 3D NHH and 3D NC′H with sequential 1 H acquisitions and 3D CANH and 3D C’NH with broadband 13 C– 15 N mixing are demonstrated using microcrystalline samples of the β1 immunoglobulin binding domain of protein G (GB1) and the chicken α-spectrin SH3 domain.

  6. Solid state NMR of proteins at high MAS frequencies: symmetry-based mixing and simultaneous acquisition of chemical shift correlation spectra

    Energy Technology Data Exchange (ETDEWEB)

    Bellstedt, Peter [Fritz Lipmann Institute, Biomolecular NMR spectroscopy, Leibniz Institute for Age Research (Germany); Herbst, Christian [Ubon Ratchathani University, Department of Physics, Faculty of Science (Thailand); Haefner, Sabine; Leppert, Joerg; Goerlach, Matthias; Ramachandran, Ramadurai, E-mail: raman@fli-leibniz.de [Fritz Lipmann Institute, Biomolecular NMR spectroscopy, Leibniz Institute for Age Research (Germany)

    2012-12-15

    We have carried out chemical shift correlation experiments with symmetry-based mixing sequences at high MAS frequencies and examined different strategies to simultaneously acquire 3D correlation spectra that are commonly required in the structural studies of proteins. The potential of numerically optimised symmetry-based mixing sequences and the simultaneous recording of chemical shift correlation spectra such as: 3D NCAC and 3D NHH with dual receivers, 3D NC Prime C and 3D C Prime NCA with sequential {sup 13}C acquisitions, 3D NHH and 3D NC Prime H with sequential {sup 1}H acquisitions and 3D CANH and 3D C'NH with broadband {sup 13}C-{sup 15}N mixing are demonstrated using microcrystalline samples of the {beta}1 immunoglobulin binding domain of protein G (GB1) and the chicken {alpha}-spectrin SH3 domain.

  7. Design of high-power, broadband 180o pulses and mixing sequences for fast MAS solid state chemical shift correlation NMR spectroscopy

    International Nuclear Information System (INIS)

    Herbst, Christian; Herbst, Jirada; Kirschstein, Anika; Leppert, Joerg; Ohlenschlaeger, Oliver; Goerlach, Matthias; Ramachandran, Ramadurai

    2009-01-01

    An approach for the design of high-power, broadband 180 o pulses and mixing sequences for generating dipolar and scalar coupling mediated 13 C- 13 C chemical shift correlation spectra of isotopically labelled biological systems at fast magic-angle spinning frequencies without 1 H decoupling during mixing is presented. Considering RF field strengths in the range of 100-120 kHz, as typically available in MAS probes employed at high spinning speeds, and limited B 1 field inhomogeneities, the Fourier coefficients defining the phase modulation profile of the RF pulses were optimised numerically to obtain broadband inversion and refocussing pulses and mixing sequences. Experimental measurements were carried out to assess the performance characteristics of the mixing sequences reported here

  8. A General Protocol for Temperature Calibration of MAS NMR Probes at Arbitrary Spinning Speeds

    Science.gov (United States)

    Guan, Xudong; Stark, Ruth E.

    2010-01-01

    A protocol using 207Pb NMR of solid lead nitrate was developed to determine the temperature of magic-angle spinning (MAS) NMR probes over a range of nominal set temperatures and spinning speeds. Using BioMAS and fastMAS probes with typical sample spinning rates of 8 and 35 kHz, respectively, empirical equations were devised to predict the respective sample temperatures. These procedures provide a straightforward recipe for temperature calibration of any MAS probe. PMID:21036557

  9. Measuring proton shift tensors with ultrafast MAS NMR.

    Science.gov (United States)

    Miah, Habeeba K; Bennett, David A; Iuga, Dinu; Titman, Jeremy J

    2013-10-01

    A new proton anisotropic-isotropic shift correlation experiment is described which operates with ultrafast MAS, resulting in good resolution of isotropic proton shifts in the detection dimension. The new experiment makes use of a recoupling sequence designed using symmetry principles which reintroduces the proton chemical shift anisotropy in the indirect dimension. The experiment has been used to measure the proton shift tensor parameters for the OH hydrogen-bonded protons in tyrosine·HCl and citric acid at Larmor frequencies of up to 850 MHz. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Relation Between Acid and Catalytic Properties of Chlorinated Gamma-Alumina. a 31p Mas Nmr and Ftir Investigation

    Directory of Open Access Journals (Sweden)

    Guillaume D.

    1999-07-01

    Full Text Available In this paper, we have studied the effect of chlorine on the surface properties of gamma-alumina, especially on their acid properties. The use of FTIR spectroscopy and 31P MAS NMR of adsorbed trimethylphosphine allows to propose a chlorination mechanism. To correlate the surface properties of these chlorinated gamma-alumina with their catalytic properties, we have used a model reaction, the cracking of n-heptane under reforming conditions. The analysis of the correlation between acid properties determined by 31P MAS NMR and the catalytic results (in terms of activities and selectivities allows to identify which sites are involved in the cracking reaction.

  11. Radiofrequency fields in MAS solid state NMR probes

    Science.gov (United States)

    Tošner, Zdeněk; Purea, Armin; Struppe, Jochem O.; Wegner, Sebastian; Engelke, Frank; Glaser, Steffen J.; Reif, Bernd

    2017-11-01

    We present a detailed analysis of the radiofrequency (RF) field over full volume of a rotor that is generated in a solenoid coil. On top of the usually considered static distribution of amplitudes along the coil axis we describe dynamic radial RF inhomogeneities induced by sample rotation. During magic angle spinning (MAS), the mechanical rotation of the sample about the magic angle, a spin packet travels through areas of different RF fields and experiences periodical modulations of both the RF amplitude and the phase. These modulations become particularly severe at the end regions of the coil where the relative RF amplitude varies up to ±25% and the RF phase changes within ±30°. Using extensive numerical simulations we demonstrate effects of RF inhomogeneity on pulse calibration and for the ramped CP experiment performed at a wide range of MAS rates. In addition, we review various methods to map RF fields using a B0 gradient along the sample (rotor axis) for imaging purposes. Under such a gradient, a nutation experiment provides directly the RF amplitude distribution, a cross polarization experiment images the correlation of the RF fields on the two channels according to the Hartmann-Hahn matching condition, while a spin-lock experiment allows to calibrate the RF amplitude employing the rotary resonance recoupling condition. Knowledge of the RF field distribution in a coil provides key to understand its effects on performance of a pulse sequence at the spectrometer and enables to set robustness requirements in the experimental design.

  12. Assessing Heterogeneity of Osteolytic Lesions in Multiple Myeloma by 1H HR-MAS NMR Metabolomics

    Directory of Open Access Journals (Sweden)

    Laurette Tavel

    2016-10-01

    Full Text Available Multiple myeloma (MM is a malignancy of plasma cells characterized by multifocal osteolytic bone lesions. Macroscopic and genetic heterogeneity has been documented within MM lesions. Understanding the bases of such heterogeneity may unveil relevant features of MM pathobiology. To this aim, we deployed unbiased 1H high-resolution magic-angle spinning (HR-MAS nuclear magnetic resonance (NMR metabolomics to analyze multiple biopsy specimens of osteolytic lesions from one case of pathological fracture caused by MM. Multivariate analyses on normalized metabolite peak integrals allowed clusterization of samples in accordance with a posteriori histological findings. We investigated the relationship between morphological and NMR features by merging morphological data and metabolite profiling into a single correlation matrix. Data-merging addressed tissue heterogeneity, and greatly facilitated the mapping of lesions and nearby healthy tissues. Our proof-of-principle study reveals integrated metabolomics and histomorphology as a promising approach for the targeted study of osteolytic lesions.

  13. Multinuclear MAS NMR studies on coked zeolites H-ZSM-5

    International Nuclear Information System (INIS)

    Ernst, H.; Freude, D.; Hunger, M.; Pfeifer, H.

    1991-01-01

    During the cracking process carbonaceous materials are deposited on the outer or inner surface of the catalyst. These deposits are in many cases the main cause of catalyst deactivation. Magic angle spinning (MAS) NMR investigations and catalytic n-hexane cracking were carried out on H-ZSM-5 zeolites after a mild hydrothermal de-alumination. By 13 C CP MAS NMR it could be shown that the enhanced catalytic activity does not enhance the coke formation and that the chemical nature of these deposits is essentially aromatic. From 1 H MAS NMR studies performed on shallow-bed activated sealed samples and 27 Al and 29 Si MAS NMR on rehydrated samples it follows that for high coke concentrations the catalyst deactivation is caused mainly by blocking of Broensted acid sites. (author). 27 refs.; 3 figs.; 2 tabs

  14. A software framework for analysing solid-state MAS NMR data

    International Nuclear Information System (INIS)

    Stevens, Tim J.; Fogh, Rasmus H.; Boucher, Wayne; Higman, Victoria A.; Eisenmenger, Frank; Bardiaux, Benjamin; Rossum, Barth-Jan van; Oschkinat, Hartmut; Laue, Ernest D.

    2011-01-01

    Solid-state magic-angle-spinning (MAS) NMR of proteins has undergone many rapid methodological developments in recent years, enabling detailed studies of protein structure, function and dynamics. Software development, however, has not kept pace with these advances and data analysis is mostly performed using tools developed for solution NMR which do not directly address solid-state specific issues. Here we present additions to the CcpNmr Analysis software package which enable easier identification of spinning side bands, straightforward analysis of double quantum spectra, automatic consideration of non-uniform labelling schemes, as well as extension of other existing features to the needs of solid-state MAS data. To underpin this, we have updated and extended the CCPN data model and experiment descriptions to include transfer types and nomenclature appropriate for solid-state NMR experiments, as well as a set of experiment prototypes covering the experiments commonly employed by solid-sate MAS protein NMR spectroscopists. This work not only improves solid-state MAS NMR data analysis but provides a platform for anyone who uses the CCPN data model for programming, data transfer, or data archival involving solid-state MAS NMR data.

  15. Advances in 27Al MAS NMR studies of geopolymers

    Czech Academy of Sciences Publication Activity Database

    Brus, Jiří; Abbrent, Sabina; Kobera, Libor; Urbanová, Martina; Cuba, P.

    2016-01-01

    Roč. 88, č. 2016 (2016), s. 79-147 ISSN 0066-4103 R&D Projects: GA ČR(CZ) GA13-24155S; GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : geopolymers * aluminosilicates * solid-state NMR Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.600, year: 2016

  16. 1H CSA parameters by ultrafast MAS NMR: Measurement and applications to structure refinement.

    Science.gov (United States)

    Miah, Habeeba K; Cresswell, Rosalie; Iuga, Dinu; Titman, Jeremy J

    2017-10-01

    A 1 H anisotropic-isotropic chemical shift correlation experiment which employs symmetry-based recoupling sequences to reintroduce the chemical shift anisotropy in ν 1 and ultrafast MAS to resolve 1 H sites in ν 2 is described. This experiment is used to measure 1 H shift parameters for L-ascorbic acid, a compound with a relatively complex hydrogen-bonding network in the solid. The 1 H CSAs of hydrogen-bonded sites with resolved isotropic shifts can be extracted directly from the recoupled lineshapes. In combination with DFT calculations, hydrogen positions in crystal structures obtained from X-ray and neutron diffraction are refined by comparison with simulations of the full two-dimensional NMR spectrum. The improved resolution afforded by the second dimension allows even unresolved hydrogen-bonded sites 1 H to be assigned and their shift parameters to be obtained. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. {sup 1}H HR-MAS NMR and S180 cells: metabolite assignment and evaluation of pulse sequence

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Aline L. de; Martinelli, Bruno César B.; Lião, Luciano M. [Universidade Federal de Goiás (UFG), Goiânia, GO (Brazil). Instituto de Química. Lab. de RMN; Pereira, Flávia C.; Silveira-Lacerda, Elisangela P. [Universidade Federal de Goiás (UFG), Goiânia, GO (Brazil). Instituto de Ciências Biológicas. Laboratório Genética Molecular e Citogenética; Alcantara, Glaucia B., E-mail: glaucia.alcantara@ufms.br [Universidade Federal de Mato Grosso do Sul (UFMS), Campo Grande, MS (Brazil). Inst. de Química

    2014-07-01

    High resolution magic angle spinning {sup 1}H nuclear magnetic resonance spectroscopy (HR-MAS NMR) is a useful technique for evaluation of intact cells and tissues. However, optimal NMR parameters are crucial in obtaining reliable results. To identify the key steps for the optimization of HR-MAS NMR parameters, we assessed different pulse sequences and NMR parameters using sarcoma 180 (S180) cells. A complete assignment of the metabolites of S180 is given to assist future studies. (author)

  18. 1H HR-MAS NMR and S180 cells: metabolite assignment and evaluation of pulse sequence

    International Nuclear Information System (INIS)

    Oliveira, Aline L. de; Martinelli, Bruno César B.; Lião, Luciano M.; Pereira, Flávia C.; Silveira-Lacerda, Elisangela P.; Alcantara, Glaucia B.

    2014-01-01

    High resolution magic angle spinning 1 H nuclear magnetic resonance spectroscopy (HR-MAS NMR) is a useful technique for evaluation of intact cells and tissues. However, optimal NMR parameters are crucial in obtaining reliable results. To identify the key steps for the optimization of HR-MAS NMR parameters, we assessed different pulse sequences and NMR parameters using sarcoma 180 (S180) cells. A complete assignment of the metabolites of S180 is given to assist future studies. (author)

  19. 29Si MAS NMR for the zeolite Y - gallium oxide system

    International Nuclear Information System (INIS)

    Sulikowski, B.; Derewinski, M.; Olejniczak, Z.; Segnowski, S.

    1994-01-01

    Wide-pore zeolites modified by gallium oxide has been prepared for catalytic use. Its physico-chemical and catalytic properties have been studied. The structure changes of the catalyst have been investigated by means of MAS NMR spectroscopy. Spectra of 29 Si has been described and discussed

  20. Proton chemical shift tensors determined by 3D ultrafast MAS double-quantum NMR spectroscopy

    International Nuclear Information System (INIS)

    Zhang, Rongchun; Mroue, Kamal H.; Ramamoorthy, Ayyalusamy

    2015-01-01

    Proton NMR spectroscopy in the solid state has recently attracted much attention owing to the significant enhancement in spectral resolution afforded by the remarkable advances in ultrafast magic angle spinning (MAS) capabilities. In particular, proton chemical shift anisotropy (CSA) has become an important tool for obtaining specific insights into inter/intra-molecular hydrogen bonding. However, even at the highest currently feasible spinning frequencies (110–120 kHz), 1 H MAS NMR spectra of rigid solids still suffer from poor resolution and severe peak overlap caused by the strong 1 H– 1 H homonuclear dipolar couplings and narrow 1 H chemical shift (CS) ranges, which render it difficult to determine the CSA of specific proton sites in the standard CSA/single-quantum (SQ) chemical shift correlation experiment. Herein, we propose a three-dimensional (3D) 1 H double-quantum (DQ) chemical shift/CSA/SQ chemical shift correlation experiment to extract the CS tensors of proton sites whose signals are not well resolved along the single-quantum chemical shift dimension. As extracted from the 3D spectrum, the F1/F3 (DQ/SQ) projection provides valuable information about 1 H– 1 H proximities, which might also reveal the hydrogen-bonding connectivities. In addition, the F2/F3 (CSA/SQ) correlation spectrum, which is similar to the regular 2D CSA/SQ correlation experiment, yields chemical shift anisotropic line shapes at different isotropic chemical shifts. More importantly, since the F2/F1 (CSA/DQ) spectrum correlates the CSA with the DQ signal induced by two neighboring proton sites, the CSA spectrum sliced at a specific DQ chemical shift position contains the CSA information of two neighboring spins indicated by the DQ chemical shift. If these two spins have different CS tensors, both tensors can be extracted by numerical fitting. We believe that this robust and elegant single-channel proton-based 3D experiment provides useful atomistic-level structural and dynamical

  1. Deuterium and lithium-6 MAS NMR studies of manganese oxide electrode materials

    Science.gov (United States)

    Paik, Younkee

    Electrolytic manganese dioxide (EMD) is used world wide as the cathode materials in both lithium and alkaline primary (non-rechargeable) batteries. We have developed deuterium and lithium MAS NMR techniques to study EMD and related manganese oxides and hydroxides, where diffraction techniques are of limited value due to a highly defective nature of the structures. Deuterons in EMD, manganite, groutite, and deuterium-intercalated pyrolusite and ramsdellite were detected by NMR, for the first time, and their locations and motions in the structures were analyzed by applying variable temperature NMR techniques. Discharge mechanisms of EMD in alkaline (aqueous) electrolytes were studied, in conjunction with step potential electrochemical spectroscopic (SPECS) method, and five distinctive discharge processes were proposed. EMD is usually heat-treated at about 300--400°C to remove water to be used in lithium batteries. Details of the effects of heat-treatment, such as structural and compositional changes as a function of heat-treatment temperature, were studied by a combination of MAS NMR, XRD, and thermogravimetric analysis. Lithium local environments in heat-treated EMD (HEMD) that were discharged in lithium cells, were described in terms of related environments found in model compounds pyrolusite and ramsdellite where specific Li + sites were detected by MAS NMR and the hyperfine shift scale method of Grey et al. Acid-leaching of Li2MnO3 represents an approach for synthesizing new or modified manganese oxide electrode materials for lithium rechargeable batteries. Progressive removal of lithium from specific crystallographic sites, followed by a gradual change of the crystal structure, was monitored by a combination of NMR and XRD techniques.

  2. HR-MAS NMR allied to chemometric on Hancornia speciosa varieties differentiation

    Energy Technology Data Exchange (ETDEWEB)

    Flores, Igor S. [Instituto Federal de Goiás (IFG), Luziânia, GO (Brazil); Silva, Andressa K.; Chaves, Lazaro J.; Collevatti, Rosane G.; Lião, Luciano M., E-mail: lucianoliao@ufg.br [Universidade Federal de Goiás (UFG), Goiânia, GO (Brazil); Furquim, Leonnardo C. [Faculdade Objetivo, GO (Brazil); Castro, Carlos F.S. [Instituto Federal de Educação, Ciência e Tecnologia Goiano (IFGoiano), GO (Brazil)

    2018-05-01

    This work describes the potential of chemometric analyses applied to {sup 1}H high-resolution magic angle spinning nuclear magnetic resonance ({sup 1}H HR-MAS NMR) data for the chemotaxonomic investigation of Hancornia speciosa (Apocynaceae) varieties. This plant, popularly known as mangaba, has a complex morphological differentiation and thus chemical analyses can be used for their taxonomic classification. In comparison to traditional techniques, {sup 1}H HR-MAS NMR allied with chemometrics provided a simple and low cost method for chemotaxonomy. Leaves of four varieties of H. speciosa from a common garden experiment was studied and demonstrated that H. speciosa var. speciosa differs from others due to its specific metabolic profile, and var. pubescens was discriminated based on its high phenolic compound content. The distinction between the latter variety and gardineri is important once it allows for the selection of samples with greater commercial value, once they produce the largest and heaviest fruits. (author)

  3. Identifying inter-residue resonances in crowded 2D {sup 13}C-{sup 13}C chemical shift correlation spectra of membrane proteins by solid-state MAS NMR difference spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Miao Yimin; Cross, Timothy A. [Florida State University, Department of Chemistry and Biochemistry (United States); Fu Riqiang, E-mail: rfu@magnet.fsu.edu [National High Magnet Field Lab (United States)

    2013-07-15

    The feasibility of using difference spectroscopy, i.e. subtraction of two correlation spectra at different mixing times, for substantially enhanced resolution in crowded two-dimensional {sup 13}C-{sup 13}C chemical shift correlation spectra is presented. With the analyses of {sup 13}C-{sup 13}C spin diffusion in simple spin systems, difference spectroscopy is proposed to partially separate the spin diffusion resonances of relatively short intra-residue distances from the longer inter-residue distances, leading to a better identification of the inter-residue resonances. Here solid-state magic-angle-spinning NMR spectra of the full length M2 protein embedded in synthetic lipid bilayers have been used to illustrate the resolution enhancement in the difference spectra. The integral membrane M2 protein of Influenza A virus assembles as a tetrameric bundle to form a proton-conducting channel that is activated by low pH and is essential for the viral lifecycle. Based on known amino acid resonance assignments from amino acid specific labeled samples of truncated M2 sequences or from time-consuming 3D experiments of uniformly labeled samples, some inter-residue resonances of the full length M2 protein can be identified in the difference spectra of uniformly {sup 13}C labeled protein that are consistent with the high resolution structure of the M2 (22-62) protein (Sharma et al., Science 330(6003):509-512, 2010)

  4. Improved background suppression in 1H MAS NMR using composite pulses

    Science.gov (United States)

    Odedra, Smita; Wimperis, Stephen

    2012-08-01

    A well known feature of 1H MAS NMR spectroscopy, particularly of solids where the concentration of 1H nuclei is low, is the presence in the spectrum of a significant broad "background" signal arising from 1H nuclei that are outside the MAS rotor and radiofrequency coil, probably located on the surfaces of the static components of the probehead. A popular method of suppressing this unwanted signal is the "depth pulse" method, consisting of a 90° pulse followed by one or two 180° pulses that are phase cycled according to the "Exorcycle" scheme, which removes signal associated with imperfect 180° pulses. Consequently, only spins in the centre of the radiofrequency coil contribute to the 1H MAS spectrum, while those experiencing a low B1 field outside the coil are suppressed. Although very effective at removing background signal from the spectrum, one drawback with this approach is that significant loss of the desired signal from the sample also occurs. Here we investigate the 1H background suppression problem and, in particular, the use of novel antisymmetric passband composite pulses to replace the simple pulses in a depth pulse experiment. We show that it is possible to improve the intensity of the 1H signals of interest while still maintaining effective background suppression. We expect that these results will be relevant to 1H MAS NMR studies of, for example, nominally perdeuterated biological samples or nominally anhydrous inorganic materials.

  5. Improved background suppression in ¹H MAS NMR using composite pulses.

    Science.gov (United States)

    Odedra, Smita; Wimperis, Stephen

    2012-08-01

    A well known feature of ¹H MAS NMR spectroscopy, particularly of solids where the concentration of ¹H nuclei is low, is the presence in the spectrum of a significant broad "background" signal arising from ¹H nuclei that are outside the MAS rotor and radiofrequency coil, probably located on the surfaces of the static components of the probehead. A popular method of suppressing this unwanted signal is the "depth pulse" method, consisting of a 90° pulse followed by one or two 180° pulses that are phase cycled according to the "Exorcycle" scheme, which removes signal associated with imperfect 180° pulses. Consequently, only spins in the centre of the radiofrequency coil contribute to the ¹H MAS spectrum, while those experiencing a low B₁ field outside the coil are suppressed. Although very effective at removing background signal from the spectrum, one drawback with this approach is that significant loss of the desired signal from the sample also occurs. Here we investigate the ¹H background suppression problem and, in particular, the use of novel antisymmetric passband composite pulses to replace the simple pulses in a depth pulse experiment. We show that it is possible to improve the intensity of the ¹H signals of interest while still maintaining effective background suppression. We expect that these results will be relevant to ¹H MAS NMR studies of, for example, nominally perdeuterated biological samples or nominally anhydrous inorganic materials. Copyright © 2012 Elsevier Inc. All rights reserved.

  6. In situ high temperature MAS NMR study of the mechanisms of catalysis. Ethane aromatization on Zn-modified zeolite BEA.

    Science.gov (United States)

    Arzumanov, Sergei S; Gabrienko, Anton A; Freude, Dieter; Stepanov, Alexander G

    2009-04-01

    Ethane conversion into aromatic hydrocarbons over Zn-modified zeolite BEA has been analyzed by high-temperature MAS NMR spectroscopy. Information about intermediates (Zn-ethyl species) and reaction products (mainly toluene and methane), which were formed under the conditions of a batch reactor, was obtained by (13)C MAS NMR. Kinetics of the reaction, which was monitored by (1)H MAS NMR in situ at the temperature of 573K, provided information about the reaction mechanism. Simulation of the experimental kinetics within the frames of the possible kinetic schemes of the reaction demonstrates that a large amount of methane evolved under ethane aromatization arises from the stage of direct ethane hydrogenolysis.

  7. Local environments and lithium adsorption on the iron oxyhydroxides lepidocrocite (gamma-FeOOH) and goethite (alpha-FeOOH): A 2H-2 and 7Li solid-state MAS NMR study

    DEFF Research Database (Denmark)

    Nielsen, Ulla Gro; Grey, Clare P.; Paik, Jonkim

    2008-01-01

    2H and 7LiMAS NMR spectroscopy techniques were applied to study the local surface and bulk environments of iron oxyhydroxide lepiclocrocite (gamma-FeOOH). 2H variable-temperature (VT) MAS NMR experiments were performed, showing the presence of short-range, strong antiferromagnetic correlations......, even at temperatures above the Neel temperature, TN, 77 K. The formation of a Li+ inner-sphere complex on the surface of lepiclocrocite was confirmed by the observation of a signal with a large 7Li hyperfine shift in the 7Li  MAS NMR spectrum. The effect of pH and relative humidity (RH...

  8. Residue specific hydration of primary cell wall potato pectin identified by solid-state 13C single-pulse MAS and CP/MAS NMR spectroscopy

    DEFF Research Database (Denmark)

    Larsen, Flemming Hofmann; Chrestensen, Inge Byg; Damager, Iben

    2011-01-01

    Hydration of rhamnogalacturonan-I (RG-I) derived from potato cell wall was analyzed by 13C single-pulse (SP) magic-angle-spinning (MAS) and 13C cross-polarization (CP) MAS nuclear magnetic resonance (NMR) and supported by 2H SP/MAS NMR experiments. The study shows that the arabinan side chains...... hydrate more readily than the galactan side chains and suggests that the overall hydration properties can be controlled by modifying the ratio of these side chains. Enzymatic modification of native (NA) RG-I provided samples with reduced content of arabinan (sample DA), galactan (sample DG), or both side...... chains (sample DB). Results of these samples suggested that hydration properties were determined by the length and character of the side chains. NA and DA exhibited similar hydration characteristics, whereas DG and DB were difficult to hydrate because of the less hydrophilic properties of the rhamnose...

  9. Variable temperature 127I MAS NMR of β-AgI

    International Nuclear Information System (INIS)

    Wagner, G.W.

    1991-01-01

    Variable temperature 127 I MAS NMR of β-AgI powder, measured from 123 to 413 K is sensitive to Ag + diffusion through the iodine lattice. In low temperature spectra, the iodine ions appear to be in nearly static environments in agreement with the low temperature crystal structure. However, at higher temperatures, substantial broadening of the central transition linewidth is consistent with the presence of two types of Ag + diffusion with activation energies of 0.17 and 0.0080 eV. (author). 15 refs.; 5 figs.; 1 tab

  10. Conformational analysis of capsaicin using 13C, 15N MAS NMR, GIAO DFT and GA calculations

    Science.gov (United States)

    Siudem, Paweł; Paradowska, Katarzyna; Bukowicki, Jarosław

    2017-10-01

    Capsaicin produced by plants from genus Capsicum exerts multiple pharmacological effects and has found applications in food and pharmaceutical industry. The alkaloid was studied by a combined approach: solid-state NMR, GA conformational search and GIAO DFT methods. The 13C CPMAS NMR spectra were recorded using variable contact time and dipolar dephasing experiments. The results of cross-polarization (CP) kinetics, such as TCP values and long T1ρH (100-200 ms), indicated that the capsaicin molecule is fairly mobile, especially at the end of the aliphatic chain. The15N MAS NMR spectrum showed one narrow signal at -255 ppm. Genetic algorithm (GA) search with multi modal optimization was used to find low-energy conformations of capsaicin. Theoretical GIAO DFT calculations were performed using different basis sets to characterize five selected conformations. 13C CPMAS NMR was used as a validation method and the experimental chemical shifts were compared with those calculated for selected stable conformers. Conformational analysis suggests that the side chain can be bent or extended. A comparison of the experimental and the calculated chemical shifts indicates that solid capsaicin does not have the same structure as those established by PWXRD.

  11. Lipid bilayer-bound conformation of an integral membrane beta barrel protein by multidimensional MAS NMR

    International Nuclear Information System (INIS)

    Eddy, Matthew T.; Su, Yongchao; Silvers, Robert; Andreas, Loren; Clark, Lindsay; Wagner, Gerhard; Pintacuda, Guido; Emsley, Lyndon; Griffin, Robert G.

    2015-01-01

    The human voltage dependent anion channel 1 (VDAC) is a 32 kDa β-barrel integral membrane protein that controls the transport of ions across the outer mitochondrial membrane. Despite the determination of VDAC solution and diffraction structures, a structural basis for the mechanism of its function is not yet fully understood. Biophysical studies suggest VDAC requires a lipid bilayer to achieve full function, motivating the need for atomic resolution structural information of VDAC in a membrane environment. Here we report an essential step toward that goal: extensive assignments of backbone and side chain resonances for VDAC in DMPC lipid bilayers via magic angle spinning nuclear magnetic resonance (MAS NMR). VDAC reconstituted into DMPC lipid bilayers spontaneously forms two-dimensional lipid crystals, showing remarkable spectral resolution (0.5–0.3 ppm for 13 C line widths and <0.5 ppm 15 N line widths at 750 MHz). In addition to the benefits of working in a lipid bilayer, several distinct advantages are observed with the lipid crystalline preparation. First, the strong signals and sharp line widths facilitated extensive NMR resonance assignments for an integral membrane β-barrel protein in lipid bilayers by MAS NMR. Second, a large number of residues in loop regions were readily observed and assigned, which can be challenging in detergent-solubilized membrane proteins where loop regions are often not detected due to line broadening from conformational exchange. Third, complete backbone and side chain chemical shift assignments could be obtained for the first 25 residues, which comprise the functionally important N-terminus. The reported assignments allow us to compare predicted torsion angles for VDAC prepared in DMPC 2D lipid crystals, DMPC liposomes, and LDAO-solubilized samples to address the possible effects of the membrane mimetic environment on the conformation of the protein. Concluding, we discuss the strengths and weaknesses of the reported

  12. Exploring high-resolution magic angle spinning (HR-MAS) NMR spectroscopy for metabonomic analysis of apples.

    Science.gov (United States)

    Vermathen, Martina; Marzorati, Mattia; Vermathen, Peter

    2012-01-01

    Classical liquid-state high-resolution (HR) NMR spectroscopy has proved a powerful tool in the metabonomic analysis of liquid food samples like fruit juices. In this paper the application of (1)H high-resolution magic angle spinning (HR-MAS) NMR spectroscopy to apple tissue is presented probing its potential for metabonomic studies. The (1)H HR-MAS NMR spectra are discussed in terms of the chemical composition of apple tissue and compared to liquid-state NMR spectra of apple juice. Differences indicate that specific metabolic changes are induced by juice preparation. The feasibility of HR-MAS NMR-based multivariate analysis is demonstrated by a study distinguishing three different apple cultivars by principal component analysis (PCA). Preliminary results are shown from subsequent studies comparing three different cultivation methods by means of PCA and partial least squares discriminant analysis (PLS-DA) of the HR-MAS NMR data. The compounds responsible for discriminating organically grown apples are discussed. Finally, an outlook of our ongoing work is given including a longitudinal study on apples.

  13. Characterization of solid polymer dispersions of active pharmaceutical ingredients by 19F MAS NMR and factor analysis

    Czech Academy of Sciences Publication Activity Database

    Urbanová, Martina; Brus, Jiří; Šeděnková, Ivana; Policianová, Olivia; Kobera, Libor

    2013-01-01

    Roč. 100, 1 January (2013), s. 59-66 ISSN 1386-1425 R&D Projects: GA ČR GPP106/11/P426; GA MŠk 2B08021 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : solid-state NMR * factor analysis * 19F MAS NMR Subject RIV: FR - Pharmacology ; Medidal Chemistry Impact factor: 2.129, year: 2013

  14. A preliminary study of the relation between adsorption and CP-MAS-NMR characteristics of fused silica model substrates

    NARCIS (Netherlands)

    Scholten, A.B.; Janssen, J.G.M.; Haan, de J.W.; Cramers, C.A.M.G.; Sandra, P.J.F.; Devos, G.; Sandra, P.

    1993-01-01

    The fumed silica model substrate Aerosil was trimethylsilylated to different extents and studied by the combination of IGC and 29Si CP-MAS-NMR. Dihydroxydisiloxane groups were shown to be chemically more reactive than monohydroxytrisiloxane groups. Chromatographic experiments showed that these

  15. Improved quantification of alite and belite in anhydrous Portland cements by 29Si MAS NMR: Effects of paramagnetic ions

    DEFF Research Database (Denmark)

    Poulsen, Søren Lundsted; Kocaba, Vanessa; Le Saoût, Gwenn

    2009-01-01

    The applicability, reliability, and repeatability of 29Si MAS NMR for determination of the quantities of alite (Ca3SiO5) and belite (Ca2SiO4) in anhydrous Portland cement was investigated in detail for 11 commercial Portland cements and the results compared with phase quantifications based...

  16. New perspectives of 19F MAS NMR in the characterization of amorphous forms of atorvastatin in dosage formulations

    Czech Academy of Sciences Publication Activity Database

    Brus, Jiří; Urbanová, Martina; Šeděnková, Ivana; Brusová, H.

    2011-01-01

    Roč. 409, 1/2 (2011), s. 62-74 ISSN 0378-5173 R&D Projects: GA MŠk 2B08021 Institutional research plan: CEZ:AV0Z40500505 Keywords : 19F MAS NMR * factor analysis * polymorphism Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.350, year: 2011

  17. Gamma-radiation induced cross-links in ethylene-propylene rubber studied by CP-MAS NMR

    International Nuclear Information System (INIS)

    Sohma, J.; Shiotani, M.; Murakami, S.

    1983-01-01

    A new technique of 13 C-NMR, the CP-MAS method, was applied to study a chemistry of cross-links induced by #betta#-irradiation of ethylene-propylene rubber. The chemical species of cross-linking points were specified with their relative concentrations by the analysis of the CP-MAS spectra obtained before and after the irradiation. It was found that the short branches were also formed by the irradiation. A comparison was made between the cross-links detected by the CP-MAS method and those obtained by the Charlesby-Pinner analysis of the gelation caused by the #betta#-irradiation. The conventional 13 C-NMR of the cross-linked and swollen EPR provided us an information on the sol parts of the sample but little information on the cross-links in the gel parts. (author)

  18. Characterization of coal structure by CP/MAS carbon-13 NMR spectrometry

    International Nuclear Information System (INIS)

    Yoshida, T.; Maekawa, Y.

    1987-01-01

    Cross-polarization (CP)/magic angle spinning (MAS) carbon-13 nuclear magnetic resonance (n.m.r.) spectrometry has been applied to the analysis of the whole structures of different ranks of coal. Three basic structural parameters, namely carbon aromaticity fa, new carbon aromaticity fa', and atomic H/C ratio for the hypothetical unsubstituted aromatic nuclei Haru/Car, were derived from the combined data of ultimate analysis, the distributions of carbon and oxygen functional groups obtained from the spectrum and the distribution of four types of methylene carbon groups in coal. Both fa and fa' values generally increased with coal rank and ranged from 0.51 to 0.71 and from 0.62 to 0.76, respectively. Haru/Car value tended to decrease with coal rank although the value was greatly affected by the types of hydroaromatic methylene carbons to aromatic rings. The values indicated that lower-rank coals consisted mainly of 1-3 aromatic rings, and higher-rank coals, 3-5 aromatic rings. 24 refs.; 5 figs.; 4 tabs

  19. Molybdenum modified phosphate glasses studied by 31P MAS NMR and Raman spectroscopy.

    Science.gov (United States)

    Szumera, Magdalena

    2015-02-25

    Glasses have been synthesized in the system P2O5-SiO2-K2O-MgO-CaO modified by addition of MoO3. Glasses were prepared by conventional fusion method from 40 g batches. The influence of Mo-cations on the analysed glass structure was investigated by means of Raman and (31)P MAS-NMR techniques. It has been found that molybdate units can form Mo[MoO4/MoO6]-O-P and/or Mo[MoO4/MoO6]-O-Si bonds with non-bridging oxygens atoms of Q2 methaphosphate units, resulting in the transformation of chain methaphosphate structure into pyrophosphate and finally into orthophosphate structure. It has been also found that increasing amount of MoO3 in the structure of investigated glasses causes their gradual depolymerization and molybdenum ions in the analysed glass matrix act as modifying cations. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. 1H-detected MAS solid-state NMR experiments enable the simultaneous mapping of rigid and dynamic domains of membrane proteins

    Science.gov (United States)

    Gopinath, T.; Nelson, Sarah E. D.; Veglia, Gianluigi

    2017-12-01

    Magic angle spinning (MAS) solid-state NMR (ssNMR) spectroscopy is emerging as a unique method for the atomic resolution structure determination of native membrane proteins in lipid bilayers. Although 13C-detected ssNMR experiments continue to play a major role, recent technological developments have made it possible to carry out 1H-detected experiments, boosting both sensitivity and resolution. Here, we describe a new set of 1H-detected hybrid pulse sequences that combine through-bond and through-space correlation elements into single experiments, enabling the simultaneous detection of rigid and dynamic domains of membrane proteins. As proof-of-principle, we applied these new pulse sequences to the membrane protein phospholamban (PLN) reconstituted in lipid bilayers under moderate MAS conditions. The cross-polarization (CP) based elements enabled the detection of the relatively immobile residues of PLN in the transmembrane domain using through-space correlations; whereas the most dynamic region, which is in equilibrium between folded and unfolded states, was mapped by through-bond INEPT-based elements. These new 1H-detected experiments will enable one to detect not only the most populated (ground) states of biomacromolecules, but also sparsely populated high-energy (excited) states for a complete characterization of protein free energy landscapes.

  1. Characterizing crystal disorder of trospium chloride: a comprehensive,(13) C CP/MAS NMR, DSC, FTIR, and XRPD study.

    Science.gov (United States)

    Urbanova, Martina; Sturcova, Adriana; Brus, Jiri; Benes, Hynek; Skorepova, Eliska; Kratochvil, Bohumil; Cejka, Jan; Sedenkova, Ivana; Kobera, Libor; Policianova, Olivia; Sturc, Antonin

    2013-04-01

    Analysis of C cross-polarization magic angle spinning (CP/MAS) nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR), and X-ray powder diffraction data of trospium chloride (TCl) products crystallized from different mixtures of water-ethanol [φ(EtOH) = 0.5-1.0] at various temperatures (0°C, 20°C) and initial concentrations (saturated solution, 30%-50% excess of solvent) revealed extensive structural variability of TCl. Although (13) C CP/MAS NMR spectra indicated broad variety of structural phases arising from molecular disorder, temperature-modulated DSC identified presence of two distinct components in the products. FTIR spectra revealed alterations in the hydrogen bonding network (ionic hydrogen bond formation), whereas the X-ray diffraction reflected unchanged unit cell parameters. These results were explained by a two-component character of TCl products in which a dominant polymorphic form is accompanied by partly separated nanocrystalline domains of a secondary phase that does not provide clear Bragg reflections. These phases slightly differ in the degree of molecular disorder, in the quality of crystal lattice and hydrogen bonding network. It is also demonstrated that, for the quality control of such complex products, (13) C CP/MAS NMR spectroscopy combined with factor analysis (FA) can satisfactorily be used for categorizing the individual samples: FA of (13) C CP/MAS NMR spectra found clear relationships between the extent of molecular disorder and crystallization conditions. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 102:1235-1248, 2013. Copyright © 2013 Wiley Periodicals, Inc.

  2. 1 H MAS NMR study of structure of hybrid siloxane-based networks and the interaction with quartz filler

    Czech Academy of Sciences Publication Activity Database

    Brus, Jiří; Škrdlantová, M.

    2001-01-01

    Roč. 281, 1-3 (2001), s. 61-71 ISSN 0022-3093 R&D Projects: GA ČR GA203/98/P290; GA AV ČR KSK2050602 Institutional research plan: CEZ:AV0Z4050913 Keywords : hybrid siloxane networks * 1 H MAS NMR spectroscopy * hydrogen bonds Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.363, year: 2001

  3. HR-MAS NMR for rapid identification of illicit substances in tablets and Blotter papers seized by Police Department

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Luciano F.; Vieira, Tarcísio S.; Lião, Luciano M., E-mail: lucianoliao@ufg.br [Universidade Federal de Goiás (UFG), Goiânia, GO (Brazil). Instituto de Química; Alcantara, Glaucia B. [Universidade Federal de Mato Grosso do Sul (UFMS), Campo Grande, MS (Brazil). Instituto de Química

    2016-07-01

    Illicit substances found in blotter papers and tablets seized by police are traditionally identified and characterized from extracts of these materials. However, the procedures involved in extraction stages can result in artifacts and even contamination of the samples to be analyzed. On the other hand, high-resolution magic angle spinning nuclear magnetic resonance (HR-MAS NMR) is a technique that requires no pretreatment steps, enabling direct analysis of the material, including the analysis of new illegal synthetic psychoactive substances. This study presents and discusses applications of the HR-MAS NMR in the analysis of tablets and blotter papers seized. Additional analysis in solution of the extracts of these materials was performed to compare the obtained spectral resolution signals. The results demonstrated that the HR-MAS NMR allowed the rapid identification of 3,4-methylenedioxy-N-methylcathinone (methylone), 4-methylmethcathinone (mephedrone), 2,5-dimethoxy-4-bromoamphetamine (DOB) and 2-(4-bromo-2,5-dimethoxyphenyl)-N-[(2- methoxyphenyl)methyl]ethanamine (25B-NBOMe) in samples of tablets and blotter papers seized in Goiás State, Brazil. (author)

  4. HR-MAS NMR for rapid identification of illicit substances in tablets and Blotter papers seized by Police Department

    International Nuclear Information System (INIS)

    Souza, Luciano F.; Vieira, Tarcísio S.; Lião, Luciano M.; Alcantara, Glaucia B.

    2016-01-01

    Illicit substances found in blotter papers and tablets seized by police are traditionally identified and characterized from extracts of these materials. However, the procedures involved in extraction stages can result in artifacts and even contamination of the samples to be analyzed. On the other hand, high-resolution magic angle spinning nuclear magnetic resonance (HR-MAS NMR) is a technique that requires no pretreatment steps, enabling direct analysis of the material, including the analysis of new illegal synthetic psychoactive substances. This study presents and discusses applications of the HR-MAS NMR in the analysis of tablets and blotter papers seized. Additional analysis in solution of the extracts of these materials was performed to compare the obtained spectral resolution signals. The results demonstrated that the HR-MAS NMR allowed the rapid identification of 3,4-methylenedioxy-N-methylcathinone (methylone), 4-methylmethcathinone (mephedrone), 2,5-dimethoxy-4-bromoamphetamine (DOB) and 2-(4-bromo-2,5-dimethoxyphenyl)-N-[(2- methoxyphenyl)methyl]ethanamine (25B-NBOMe) in samples of tablets and blotter papers seized in Goiás State, Brazil. (author)

  5. Investigating sorption on iron-oxyhydroxide soil minerals by solid-state NMR spectroscopy: a 6Li MAS NMR study of adsorption and absorption on goethite

    DEFF Research Database (Denmark)

    Nielsen, Ulla Gro; Paik, Younkee; Julmis, Keinia

    2005-01-01

    High-resolution 2H MAS NMR spectra can be obtained for nanocrystalline particles of goethite (alpha-FeOOH, particle size approximately 4-10 nm) at room temperature, facilitating NMR studies of sorption under environmentally relevant conditions. Li sorption was investigated as a function of pH, th...... on the goethite surface. Even larger Li hyperfine shifts (289 ppm) were observed for Li+-exchanged goethite, which contains lithium ions in the tunnels of the goethite structure, confirming the Li assignment of the 145 ppm Li resonance to the surface sites. Udgivelsesdato: 2005-Oct-6...

  6. 27Al MAS NMR spectroscopic identification of reaction intermediates in the carbothermal reduction and nitridation of alumina

    International Nuclear Information System (INIS)

    Jung, Woo-Sik; Chae, Seen-Ae

    2010-01-01

    The reaction intermediates in the carbothermal reduction and nitridation (CRN) reaction of γ-Al 2 O 3 were identified by 27 Al magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. This identification ruled out the possibility of a reaction mechanism involving the gaseous reaction intermediates. In the CRN reaction of γ-Al 2 O 3 , AlO 4 units were converted to AlN stepwise via AlN x O 4-x (x = 1, 2, 3) intermediates, while AlO 6 units were more slowly converted to AlN than AlO 4 units and the NMR peaks of partially nitridated AlO 6 units were not detected. The NMR peak intensities of partially nitridated AlO 4 units became weaker with increasing reaction temperature.

  7. A new aluminium-hydrate species in hydrated Portland cements characterized by 27Al and 29Si MAS NMR spectroscopy

    International Nuclear Information System (INIS)

    Andersen, Morten Daugaard; Jakobsen, Hans J.; Skibsted, Jorgen

    2006-01-01

    Recent 27 Al MAS NMR studies of hydrated Portland cements and calcium-silicate-hydrate (C-S-H) phases have shown a resonance from Al in octahedral coordination, which cannot be assigned to the well-known aluminate species in hydrated Portland cements. This resonance, which exhibits the isotropic chemical shift δ iso = 5.0 ppm and the quadrupole product parameter P Q = 1.2 MHz, has been characterized in detail by 27 Al MAS and 27 Al{ 1 H} CP/MAS NMR for different hydrated white Portland cements and C-S-H phases. These experiments demonstrate that the resonance originates from an amorphous or disordered aluminate hydrate which contains Al(OH) 6 3- or O x Al(OH) 6-x (3+x)- units. The formation of the new aluminate hydrate is related to the formation of C-S-H at ambient temperatures, however, it decomposes by thermal treatment at temperatures of 70-90 o C. From the experiments in this work it is proposed that the new aluminate hydrate is either an amorphous/disordered aluminate hydroxide or a calcium aluminate hydrate, produced as a separate phase or as a nanostructured surface precipitate on the C-S-H phase. Finally, the possibilities of Al 3+ for Ca 2+ substitution in the principal layers and interlayers of the C-S-H structure are discussed

  8. Determination of the structural changes by Raman and {sup 13}C CP/MAS NMR spectroscopy on native corn starch with plasticizers

    Energy Technology Data Exchange (ETDEWEB)

    Cozar, O. [Academy of Romanian Scientists, Splaiul Independentei 54, 050094, Bucharest, Romania and National Institute of Research-Development for Machines and Installations Designed to Agriculture and Food Industry - INMA Bucureşti - Cluj-Napoca Branch (Romania); Filip, C.; Tripon, C. [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath, 400293 Cluj-Napoca (Romania); Cioica, N.; Coţa, C.; Nagy, E. M. [National Institute of Research-Development for Machines and Installations Designed to Agriculture and Food Industry - INMA Bucureşti - Cluj-Napoca Branch, RO-400458 Cluj-Napoca (Romania)

    2013-11-13

    The plasticizing - antiplasticizing effect of water and glycerol contents on native corn starch samples is investigated by FT-Raman and {sup 13}C CP/MAS NMR spectroscopy. The presence of both amorphous and crystalline structural phases was evidenced in pure native corn starch and also in the samples containing plasticizers. Among the crystalline starch structures, the A- and V- types were suggested by CP/MAS NMR spectra.

  9. 1H HR-MAS NMR Spectroscopy and the Metabolite Determination of Typical Foods in Mediterranean Diet

    Directory of Open Access Journals (Sweden)

    Carmelo Corsaro

    2015-01-01

    Full Text Available NMR spectroscopy has become an experimental technique widely used in food science. The experimental procedures that allow precise and quantitative analysis on different foods are relatively simple. For a better sensitivity and resolution, NMR spectroscopy is usually applied to liquid sample by means of extraction procedures that can be addressed to the observation of particular compounds. For the study of semisolid systems such as intact tissues, High-Resolution Magic Angle Spinning (HR-MAS has received great attention within the biomedical area and beyond. Metabolic profiling and metabolism changes can be investigated both in animal organs and in foods. In this work we present a proton HR-MAS NMR study on the typical vegetable foods of Mediterranean diet such as the Protected Geographical Indication (PGI cherry tomato of Pachino, the PGI Interdonato lemon of Messina, several Protected Designation of Origin (PDO extra virgin olive oils from Sicily, and the Traditional Italian Food Product (PAT red garlic of Nubia. We were able to identify and quantify the main metabolites within the studied systems that can be used for their characterization and authentication.

  10. 27Al Magic Angle Spinning–Nuclear Magnetic Resonance (MAS-NMR) Analyses Applied to Historical Mortars

    Czech Academy of Sciences Publication Activity Database

    Hanzlíček, Tomáš; Perná, Ivana; Brus, Jiří

    2013-01-01

    Roč. 7, č. 2 (2013), s. 153-164 ISSN 1558-3058 R&D Projects: GA AV ČR IAA300460702 Institutional research plan: CEZ:AV0Z30460519; CEZ:AV0Z40500505 Keywords : mortars * magic angle spinning –nuclear magnetic resonance (MAS-NMR) in solid state * alumina-silicates Subject RIV: DM - Solid Waste and Recycling Impact factor: 0.714, year: 2013 http://www.tandfonline.com/doi/abs/10.1080/15583058.2011.624253

  11. Chemical profile of beans cultivars (Phaseolus vulgaris) by 1H NMR - high resolution magic angle spinning (HR-MAS);Perfil quimico de cultivares de feijao (Phaseolus vulgaris) pela tecnica de high resolution magic angle spinning (HR-MAS)

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Luciano Morais; Choze, Rafael; Cavalcante, Pedro Paulo Araujo; Santos, Suzana da Costa; Ferri, Pedro Henrique, E-mail: luciano@quimica.ufg.b [Universidade Federal de Goias (UFG), Goiania, GO (Brazil). Inst. de Quimica; Ferreira, Antonio Gilberto [Universidade Federal de Sao Carlos (UFScar), SP (Brazil). Dept. de Quimica

    2010-07-01

    The application of one-dimensional proton high-resolution magic angle spinning ({sup 1}H HR-MAS) NMR combined with a typical advantages of solid and liquid-state NMR techniques was used as input variables for the multivariate statistical analysis. In this paper, different cultivars of beans (Phaseolus vulgaris) developed and in development by EMBRAPA - Arroz e Feijao were analyzed by {sup 1}H HR-MAS, which have been demonstrated to be a valuable tool in its differentiation according chemical composition and avoid the manipulation of the samples as used in other techniques. (author)

  12. Lightweight hydrogen-storage material Mg0.65Sc0.35D2 studied with 2H and 2H–{45Sc} MAS NMR exchange spectroscopy

    NARCIS (Netherlands)

    Srinivasan, S.; Magusin, P.C.M.M.

    2011-01-01

    Using double-quantum 2H MAS NMR with 45Sc recoupling and Bloch–Siegert compensated 2H–{45Sc} TRAPDOR we have identified the overlapping NMR signals of deuterium with and without scandium neighbors in Mg0.65Sc0.35D2, a candidate lightweight material for hydrogen storage. At room temperature we also

  13. Microscopic structural analysis of fractured silk fibers from Bombyx mori and Samia cynthia ricini using 13C CP/MAS NMR with a 1 mm microcoil MAS NMR probehead

    KAUST Repository

    Yamauchi, Kazuo

    2010-07-01

    Conformational changes have been studied in silk fibers from the domestic silkworm Bombyx mori and a wild silkworm Samia cynthia ricini as a result of fractured by stretching. About 300 samples consisting of only the fractured regions of [1-13C]Ala or [1-13C]Gly labeled silk fibers were collected and observed by 13C CP/MAS NMR spectra. The total amount of these fractured fibers is only about 1 mg and therefore we used a home-built 1 mm microcoil MAS NMR probehead. A very small increase in the fraction of random coil was noted for the alanine regions of both silk fibroins and for the glycine region of B. mori silk fibroin. However, there is no difference in the spectra before and after fractured for the glycine region of S. c. ricini silk fibroin. Thus, the influence of fracture occurs exclusively at the Ala region for S. c. ricini. The relationship between sequence, fracture and structure is discussed. © 2010 Elsevier Inc. All rights reserved.

  14. High field 27Al MAS NMR and TPD studies of active sites in ethanol dehydration using thermally treated transitional aluminas as catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Jian Zhi; Xu, Suochang; Kwak, Ja Hun; Hu, Mary Y.; Wan, Chuan; Zhao, Zhenchao; Szanyi, Janos; Bao, Xinhe; Han, Xiuwen; Wang, Yong; Peden, Charles H. F.

    2016-04-01

    High field quantitative 27Al MAS NMR and temperature programmed desorption (TPD) of ethanol are used to study the surface and phase transformation of gamma-Al2O3 during calcination in the temperature range of 500 to 1300 degrees C. Following ethanol adsorption, ethylene is generated during TPD with a desorption temperature > 200 degrees C. With increasing calcination temperature prior to TPD, the amount of ethylene produced decreases monotonically. Significantly, 27Al MAS NMR reveals that the amount of penta-coordinate Al3+ ions (Lewis acid sites) also decreases with increasing calcination temperature. In fact, a strong correlation between the amount of penta-coordinate Al3+ ions and the amount of strongly adsorbed ethanol molecules (i.e., the ones that convert to ethylene during TPD) is obtained. This result indicates that the penta-coordinate aluminum sites are the catalytic active sites on alumina surfaces during ethanol dehydration reaction across the entire course of gamma- to alpha-Al2O3 phase transformations.

  15. Acceleration of natural-abundance solid-state MAS NMR measurements on bone by paramagnetic relaxation from gadolinium-DTPA

    Science.gov (United States)

    Mroue, Kamal H.; Zhang, Rongchun; Zhu, Peizhi; McNerny, Erin; Kohn, David H.; Morris, Michael D.; Ramamoorthy, Ayyalusamy

    2014-07-01

    Reducing the data collection time without affecting the signal intensity and spectral resolution is one of the major challenges for the widespread application of multidimensional nuclear magnetic resonance (NMR) spectroscopy, especially in experiments conducted on complex heterogeneous biological systems such as bone. In most of these experiments, the NMR data collection time is ultimately governed by the proton spin-lattice relaxation times (T1). For over two decades, gadolinium(III)-DTPA (Gd-DTPA, DTPA = Diethylene triamine pentaacetic acid) has been one of the most widely used contrast-enhancement agents in magnetic resonance imaging (MRI). In this study, we demonstrate that Gd-DTPA can also be effectively used to enhance the longitudinal relaxation rates of protons in solid-state NMR experiments conducted on bone without significant line-broadening and chemical-shift-perturbation side effects. Using bovine cortical bone samples incubated in different concentrations of Gd-DTPA complex, the 1H T1 values were calculated from data collected by 1H spin-inversion recovery method detected in natural-abundance 13C cross-polarization magic angle spinning (CPMAS) NMR experiments. Our results reveal that the 1H T1 values can be successfully reduced by a factor of 3.5 using as low as 10 mM Gd-DTPA without reducing the spectral resolution and thus enabling faster data acquisition of the 13C CPMAS spectra. These results obtained from 13C-detected CPMAS experiments were further confirmed using 1H-detected ultrafast MAS experiments on Gd-DTPA doped bone samples. This approach considerably improves the signal-to-noise ratio per unit time of NMR experiments applied to bone samples by reducing the experimental time required to acquire the same number of scans.

  16. 6Li MAS NMR Study of Lithium Insertion into Hydrothermally Prepared Li-Ti-O Spinel

    Czech Academy of Sciences Publication Activity Database

    Krtil, Petr; Dědeček, Jiří; Kostlánová, Tereza; Brus, Jiří

    2004-01-01

    Roč. 7, č. 7 (2004), A163-A166 ISSN 1099-0062 R&D Projects: GA ČR GA203/03/0823 Institutional research plan: CEZ:AV0Z4040901 Keywords : lithium insertion * spinel * NMR Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.271, year: 2004

  17. Incorporation of phosphorus guest ions in the calcium silicate phases of Portland cement from 31P MAS NMR spectroscopy.

    Science.gov (United States)

    Poulsen, Søren L; Jakobsen, Hans J; Skibsted, Jørgen

    2010-06-21

    Portland cements may contain small quantities of phosphorus (typically below 0.5 wt % P(2)O(5)), originating from either the raw materials or alternative sources of fuel used to heat the cement kilns. This work reports the first (31)P MAS NMR study of anhydrous and hydrated Portland cements that focuses on the phase and site preferences of the (PO(4))(3-) guest ions in the main clinker phases and hydration products. The observed (31)P chemical shifts (10 to -2 ppm), the (31)P chemical shift anisotropy, and the resemblance of the lineshapes in the (31)P and (29)Si MAS NMR spectra strongly suggest that (PO(4))(3-) units are incorporated in the calcium silicate phases, alite (Ca(3)SiO(5)) and belite (Ca(2)SiO(4)), by substitution for (SiO(4))(4-) tetrahedra. This assignment is further supported by a determination of the spin-lattice relaxation times for (31)P in alite and belite, which exhibit the same ratio as observed for the corresponding (29)Si relaxation times. From simulations of the intensities, observed in inversion-recovery spectra for a white Portland cement, it is deduced that 1.3% and 2.1% of the Si sites in alite and belite, respectively, are replaced by phosphorus. Charge balance may potentially be achieved to some extent by a coupled substitution mechanism where Ca(2+) is replaced by Fe(3+) ions, which may account for the interaction of the (31)P spins with paramagnetic Fe(3+) ions as observed for the ordinary Portland cements. A minor fraction of phosphorus may also be present in the separate phase Ca(3)(PO(4))(2), as indicated by the observation of a narrow resonance at delta((31)P) = 3.0 ppm for two of the studied cements. (31)P{(1)H} CP/MAS NMR spectra following the hydration of a white Portland cement show that the resonances from the hydrous phosphate species fall in the same spectral range as observed for (PO(4))(3-) incorporated in alite. This similarity and the absence of a large (31)P chemical shift ansitropy indicate that the hydrous (PO(4

  18. 13C CP MAS NMR and GIAO-CHF/DFT calculations of flavonoids: Morin, kaempferol, tricin, genistein, formononetin and 3,7-dihydroxyflavone

    Science.gov (United States)

    Zielińska, Agnieszka; Paradowska, Katarzyna; Jakowski, Jacek; Wawer, Iwona

    2008-02-01

    13C CP MAS NMR spectra of the flavonoids: morin, kaempferol, 3,7-dihydroxyflavone, tricin and isoflavones: genistein and formononetin were recorded to characterize solid-state conformations. Intramolecular hydrogen bonds forming five-, six- and seven-membered rings are present in the two morin molecules in the crystals - their 13C resonances have been assigned with the aid of the calculated shielding constants. Linear relationships between the calculated shielding constants σDFT (ppm) and chemical shifts ( δCPMAS, ppm) were obtained for all studied compounds. Higher correlation coefficients suggest that the conformation with "clockwise" orientation of both OH groups is more probable in the solid 3,7-dihydroxyflavone, whereas in the solid formononetin the OH and OCH 3 substituents are directed "anticlockwise". The barrier to the rotation of phenyl ring B decreases in the order: morin (2'-OH, 3-OH) > kaempferol (3-OH) > tricin.

  19. Glycerin-Induced Conformational Changes in Bombyx mori Silk Fibroin Film Monitored by (13)C CP/MAS NMR and ¹H DQMAS NMR.

    Science.gov (United States)

    Asakura, Tetsuo; Endo, Masanori; Hirayama, Misaki; Arai, Hiroki; Aoki, Akihiro; Tasei, Yugo

    2016-09-09

    In order to improve the stiff and brittle characteristics of pure Bombyx mori (B. mori) silk fibroin (SF) film in the dry state, glycerin (Glyc) has been used as a plasticizer. However, there have been very limited studies on the structural characterization of the Glyc-blended SF film. In this study, (13)C Cross Polarization/Magic Angle Spinning nuclear magnetic resonance (CP/MAS NMR) was used to monitor the conformational changes in the films by changing the Glyc concentration. The presence of only 5 wt % Glyc in the film induced a significant conformational change in SF where Silk I* (repeated type II β-turn and no α-helix) newly appeared. Upon further increase in Glyc concentration, the percentage of Silk I* increased linearly up to 9 wt % Glyc and then tended to be almost constant (30%). This value (30%) was the same as the fraction of Ala residue within the Silk I* form out of all Ala residues of SF present in B. mori mature silkworm. The ¹H DQMAS NMR spectra of Glyc-blended SF films confirmed the appearance of Silk I* in the Glyc-blended SF film. A structural model of Glyc-SF complex including the Silk I* form was proposed with the guidance of the Molecular Dynamics (MD) simulation using ¹H-¹H distance constraints obtained from the ¹H Double-Quantum Magic Angle Spinning (DQMAS) NMR spectra.

  20. Hydration properties and phosphorous speciation in native, gelatinized and enzymatically modified potato starch analyzed by solid-state MAS NMR

    DEFF Research Database (Denmark)

    Larsen, Flemming H.; Kasprzak, Miroslaw Marek; Lærke, Helle Nygaard

    2013-01-01

    Hydration of granular, gelatinized and molecularly modified states of potato starch in terms of molecular mobility were analyzed by 13C and 31P solid-state MAS NMR. Gelatinization (GEL) tremendously reduced the immobile fraction compared to native (NA) starch granules. This effect was enhanced...... by enzyme-assisted catalytic branching with branching enzyme (BE) or combined BE and β-amylase (BB) catalyzed exo-hydrolysis. Carbons of the glycosidic α-1,6 linkages required high hydration rates before adopting uniform chemical shifts indicating solid-state disorder and poor water accessibility...... regions was only observed in NA starch. Moreover phosphorous was observed in a minor pH-insensitive form and as major phosphate in hydrated GEL and BE starches....

  1. Studies using 27Al MAS NMR of AFm and AFt phases and the formation of Friedel's salt

    International Nuclear Information System (INIS)

    Jones, M.R.; Macphee, D.E.; Chudek, J.A.; Hunter, G.; Lannegrand, R.; Talero, R.; Scrimgeour, S.N.

    2003-01-01

    This paper describes the application of the magic angle spinning (MAS) NMR spectroscopy to study the chemical environment of 27 Al-bearing phases in Portland cement-based concrete. A specific methodology is described that allows reliable spectra to be determined for combinations of different types of cements and fillers (in this case, Portland cement, fly ash, slag, silica fume, metakaolin and limestone filler). As well as the study of 'molecular structure' of cement matrix, the paper reviews the mechanism of Friedel's salt formation in cement systems. Mechanisms based on ion exchange of chloride for hydroxide in hydroxy-AF m and on chloride absorption on formation are discussed. Finally, the nature of the chloride/hydrate binding phenomena are described to provide a reasonable robust and fundamental picture of the role different cements can play in the provision of overall concrete durability to chloride ingress from a chemical perspective

  2. Surface Characterization of Some Novel Bonded Phase Packing Materials for HPLC Columns Using MAS-NMR Spectroscopy

    Directory of Open Access Journals (Sweden)

    Jude Abia

    2015-03-01

    Full Text Available Information on the surface properties of three novel chemically bonded phase packing materials for High performance liquid chromatography (HPLC were obtained using spectra obtained by solid state cross-polarization (CP magic-angle spinning (MAS nuclear magnetic resonance (NMR spectroscopic experiments for the 29Si, and 13C nuclei. These packing materials were: Cogent bidentate C18 bonded to type-C silica, hybrid packing materials XTerra MS C18, and XBridge Prep. C18. The spectra obtained using cross-polarization magic angle spinning (CP-MAS on the Cogent bidentate C18 bonded to type-C silica show the surface to be densely populated with hydride groups (Si-H, with a relative surface coverage exceeding 80%. The hybrid packing materials XTerra and XBridge gave spectra that reveal the silicon atoms to be bonded to organic moieties embedded in the molecular structure of these materials with over 90% of the alkyl silicon atoms found within the completely condensed silicon environments. The hydrolytic stability of these materials were investigated in acidic aqueous solutions at pHs of 7.0 and 3.0, and it was found that while the samples of XTerra and XBridge were not affected by hydrolysis at this pH range, the sample of Cogent lost a significant proportion of its Si-H groups after five days of treatment in acidic aqueous solution.

  3. 1H MAS NMR (magic-angle spinning nuclear magnetic resonance) techniques for the quantitative determination of hydrogen types in solid catalysts and supports.

    Science.gov (United States)

    Kennedy, Gordon J; Afeworki, Mobae; Calabro, David C; Chase, Clarence E; Smiley, Randolph J

    2004-06-01

    Distinct hydrogen species are present in important inorganic solids such as zeolites, silicoaluminophosphates (SAPOs), mesoporous materials, amorphous silicas, and aluminas. These H species include hydrogens associated with acidic sites such as Al(OH)Si, non-framework aluminum sites, silanols, and surface functionalities. Direct and quantitative methodology to identify, measure, and monitor these hydrogen species are key to monitoring catalyst activity, optimizing synthesis conditions, tracking post-synthesis structural modifications, and in the preparation of novel catalytic materials. Many workers have developed several techniques to address these issues, including 1H MAS NMR (magic-angle spinning nuclear magnetic resonance). 1H MAS NMR offers many potential advantages over other techniques, but care is needed in recognizing experimental limitations and developing sample handling and NMR methodology to obtain quantitatively reliable data. A simplified approach is described that permits vacuum dehydration of multiple samples simultaneously and directly in the MAS rotor without the need for epoxy, flame sealing, or extensive glovebox use. We have found that careful optimization of important NMR conditions, such as magnetic field homogeneity and magic angle setting are necessary to acquire quantitative, high-resolution spectra that accurately measure the concentrations of the different hydrogen species present. Details of this 1H MAS NMR methodology with representative applications to zeolites, SAPOs, M41S, and silicas as a function of synthesis conditions and post-synthesis treatments (i.e., steaming, thermal dehydroxylation, and functionalization) are presented.

  4. Quality of spelt pasta enriched with eggs and identification of eggs using 13C MAS NMR spectroscopy

    Directory of Open Access Journals (Sweden)

    Filipović Jelena S.

    2015-01-01

    Full Text Available This paper deals with the characteristics of spelt pasta enriched with eggs. Eggs were added to spelt farina in the quantity of 0, 124 or 248 g/kg (equivalent to 0, 3 or 6 eggs, respectively. Post-hoc Tukey’s HSD test at 95% confidence limit showed significant differences between various samples. Relatively low coefficients of variation have been obtained for each applied assay (1.25-12.42%, which confirmed the high accuracy measurements and statistically significant results. Standard score analysis is applied for accessing the contribution of eggs content to spelt pasta quality. Maximum scores regarding quality (0.89 and chemical characteristics (0.70, have been obtained for 6 eggs spelt pasta formulation. It is also shown that the presence of eggs in pasta can be clearly confirmed by 13C MAS NMR spectroscopy. Simultaneous increase in area of peak positioned at 29.5 and 176 ppm is directly associated with the increase in the content of added eggs in the corresponding samples. Pertinent data point at positive contribution of eggs to the spelt pasta and also that NMR spectrum can be used in the egg quantity control. [Projekat Ministarstva nauke Republike Srbije, br. TRI 46005 i br. TR 31029

  5. Analysis of Hydroperoxides in Solid Polyethylene by MAS (13)C NMR and EPR

    International Nuclear Information System (INIS)

    ASSINK, ROGER A.; CELINA, MATHIAS C.; DUNBAR, TIMOTHY D.; ALAM, TODD M.; CLOUGH, ROGER LEE; GILLEN, KENNETH T.

    1999-01-01

    13 C-enriched polyethylene was subjected to γ-irradiation in the presence of air at 25 and 80 C for total doses ranging from 71 to 355 kGy. Significant quantities of hydroperoxides were detected in the 25 C irradiated sample by 13 C magic angle spinning NMR spectroscopy. This method of detection was performed on the solid polymer and required no chemical derivatization or addition of solvent. The chemical stability and subsequent products of the hydroperoxide species were studied by annealing the irradiated samples in air at temperatures ranging from 22 to 110 C. A time-temperature superposition analysis provided an activation energy of 108 kJ/mol for the hydroperoxide decomposition process. The primary products of hydroperoxide decomposition were ketones and secondary alcohols with lesser amounts of acids and esters. EPR measurements suggest that the reactive hydroperoxide species reside in the amorphous phase of polyethylene, consistent with degradation occurring in the amorphous phase

  6. A MAS NMR and DRIFT study of the Ga species in Ga/H-ZSM5 catalysts and their effect on propane ammoxidation

    NARCIS (Netherlands)

    Pal, P.; Quartararo, J.; Hamid, abd S.B.; Derouane, E.G.; Védrine, J.C.; Magusin, P.C.M.M.; Anderson, B.G.

    2005-01-01

    71Ga, 27Al and 29Si MAS-NMR and DRIFT spectroscopies were used to characterize the state of gallium in Ga/H-ZSM5 catalysts tested for their ability to catalyse the ammoxidation of propane. Ga-species were observed in two different possible environments: octahedrally-coordinated gallium in small

  7. Hydration kinetics for the alite, belite, and calcium aluminate phase in Portland cements from 27Al and 29Si MAS NMR spectroscopy

    DEFF Research Database (Denmark)

    Skibsted, Jørgen; Jensen, Ole Mejlhede; Jakobsen, Hans Jørgen

    1997-01-01

    29Si magic-angle spinning (MAS) NMR spectroscopy is shown to be a valuable tool for obtaining the quantities of alite and belite in hydrated Portland cements. The hydration (1-180 days) of a white Portland cement with 10 wt.% silica fume added is investigated and the degrees of hydration for alite...

  8. Anomalous H/D isotope effect on 35Cl NQR frequencies and H/D isotope effect on 1H MAS NMR spectra in pyrrolidinium p-chlorobenzoate

    International Nuclear Information System (INIS)

    Nakano, Ryo; Honda, Hisashi; Nakata, Eiichi; Takamizawa, Satoshi; Noro, Sumiko; Kimura, Taiki; Kyo, Shin-shin; Ishimaru, Shin'ichi; Miyake, Ryosuke

    2010-01-01

    An anomalous isotope effect was observed in the 35 Cl NQR frequency of pyrrolidinium p-chlorobenzoate (C 4 H 8 NH 2 + ·ClC 6 H 4 COO - ) by deuterium substitution of hydrogen atoms which form two kinds of N-H...O type hydrogen bonds. Large negative frequency shifts of the 35 Cl resonance lines, reaching 309 kHz at 77 K and 267 kHz at 293 K, were obtained upon deuteration, although the Cl atom in the molecule formed no hydrogen bonds in the crystal. 1 H MAS NMR lines showed significant changes by the deuterium substitution, while in contrast, small shifts of 13 C CP/MAS NMR signals were obtained. Our measurements of 1 H NMR spin-lattice relaxation times (T 1 ) suggested that the H/D isotope shifts detected from the 35 Cl NQR frequencies and 1 H NMR spectra are due to structural changes rather than molecular dynamics. Single-crystal X-ray diffraction measurements showed two remarkable H/D isotope differences in the molecular arrangements, (1) the N-H length along the crystallographic a axis became 1 pm shorter, and (2) the dihedral angle between benzene and the pyrrolidine ring changed by 1.1(2)deg upon deuteration. Using density functional theory estimations, the anomalous 35 Cl NQR frequency shifts and 1 H MAS NMR line-shape changes could be explained by the dihedral angle change rather than the N-H length difference. (author)

  9. Structural investigations of borosilicate glasses containing MoO{sub 3} by MAS NMR and Raman spectroscopies

    Energy Technology Data Exchange (ETDEWEB)

    Caurant, D., E-mail: daniel-caurant@enscp.f [Laboratoire de Chimie de la Matiere Condensee de Paris, UMR-CNRS 7574, Ecole Nationale Superieure de Chimie de Paris (ENSCP, ParisTech), 11 rue Pierre et Marie Curie, 75231 Paris (France); Majerus, O.; Fadel, E.; Quintas, A. [Laboratoire de Chimie de la Matiere Condensee de Paris, UMR-CNRS 7574, Ecole Nationale Superieure de Chimie de Paris (ENSCP, ParisTech), 11 rue Pierre et Marie Curie, 75231 Paris (France); Gervais, C. [Laboratoire de Chimie de la Matiere Condensee de Paris, UMR-CNRS 7574, Universite Pierre et Marie Curie, 75252 Paris (France); Charpentier, T. [CEA, IRAMIS, Service Interdisciplinaire sur les Systemes Moleculaires et Materiaux, CEA Saclay, 91191 Gif-sur-Yvette (France); Neuville, D. [Physique des Mineraux et des Magmas, UMR-CNRS 7047, Institut de Physique du Globe, place Jussieu, 75252 Paris (France)

    2010-01-01

    High molybdenum concentration in glass compositions may lead to alkali and alkaline-earth molybdates crystallization during melt cooling that must be controlled particularly during the preparation of highly radioactive nuclear glassy waste forms. To understand the effect of molybdenum addition on the structure of a simplified nuclear glass and to know how composition changes can affect molybdates crystallization tendency, the structure of two glass series belonging to the SiO{sub 2}-B{sub 2}O{sub 3}-Na{sub 2}O-CaO-MoO{sub 3} system was studied by {sup 29}Si, {sup 11}B, {sup 23}Na MAS NMR and Raman spectroscopies by increasing MoO{sub 3} or B{sub 2}O{sub 3} concentrations. Increasing MoO{sub 3} amount induced an increase of the silicate network reticulation but no significant effect was observed on the proportion of BO{sub 4}{sup -} units and on the distribution of Na{sup +} cations in glass structure. By increasing B{sub 2}O{sub 3} concentration, a strong evolution of the distribution of Na{sup +} cations was observed that could explain the evolution of the nature of molybdate crystals (CaMoO{sub 4} or Na{sub 2}MoO{sub 4}) formed during melt cooling.

  10. Structure of Selected Derivates of p-Hydroxy Cynamonic Acid According to 13C CP MAS NMR and DFT Calculation

    International Nuclear Information System (INIS)

    Pisklak, D.M.; Wawer, I.; Tkaczyk, M.

    2005-01-01

    Derivatives of p-hydroxy cynamonic acid are widely occurring in fruits, vegetables, tea and coffee. They exhibit strong antioxidant activity due to the presence of phenolic group. Epidemiological, biological and biochemical data support health beneficial role of this group of compounds and anticarcinogenic, antimutagenic and antiinflamatory effects have been reported. The most common caffeic acid contributes significantly to the total polyphenol intake and has been suggested to play a role in the apparent association between the regular consumption of polyphenol-rich food and beverages, and the prevetion of inflammatory and proliferative diseases. 13 C MAS NMR spectra were recorded on a BRUKER DSX 400 spectrometer at 400,13. Powder samples were spun in a 4 mm rotor at 10 kHz ( 13 C). Signals were assigned:- By comparison with solution spectra; - Using dipolar dephasing and variable contact time experiments; - Confirmed by DFT calculations of shielding constants. The differences in chemical shifts between solution and solid state spectra are due to the formation of intramolecular and intermolecular hydrogen bonds, including C-OH...OC within cyclic dimers. (author)

  11. Determination of structural topology of a membrane protein in lipid bilayers using polarization optimized experiments (POE) for static and MAS solid state NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Mote, Kaustubh R. [University of Minnesota, Department of Chemistry (United States); Gopinath, T. [University of Minnesota, Department of Biochemistry, Molecular Biology and Biophysics (United States); Veglia, Gianluigi, E-mail: vegli001@umn.edu [University of Minnesota, Department of Chemistry (United States)

    2013-10-15

    The low sensitivity inherent to both the static and magic angle spinning techniques of solid-state NMR (ssNMR) spectroscopy has thus far limited the routine application of multidimensional experiments to determine the structure of membrane proteins in lipid bilayers. Here, we demonstrate the advantage of using a recently developed class of experiments, polarization optimized experiments, for both static and MAS spectroscopy to achieve higher sensitivity and substantial time-savings for 2D and 3D experiments. We used sarcolipin, a single pass membrane protein, reconstituted in oriented bicelles (for oriented ssNMR) and multilamellar vesicles (for MAS ssNMR) as a benchmark. The restraints derived by these experiments are then combined into a hybrid energy function to allow simultaneous determination of structure and topology. The resulting structural ensemble converged to a helical conformation with a backbone RMSD {approx}0.44 A, a tilt angle of 24 Degree-Sign {+-} 1 Degree-Sign , and an azimuthal angle of 55 Degree-Sign {+-} 6 Degree-Sign . This work represents a crucial first step toward obtaining high-resolution structures of large membrane proteins using combined multidimensional oriented solid-state NMR and magic angle spinning solid-state NMR.

  12. 1H and 23Na MAS NMR spectroscopy of cationic species in CO2 selective alkaline earth metal porous silicoaluminophosphates prepared via liquid and solid state ion exchange

    International Nuclear Information System (INIS)

    Arévalo-Hidalgo, Ana G.; Dugar, Sneha; Fu, Riqiang; Hernández-Maldonado, Arturo J.

    2012-01-01

    The location of extraframework cations in Sr 2+ and Ba 2+ ion-exchanged SAPO-34 was estimated by means of 1 H and 23 Na MAS NMR spectroscopy and spectral deconvolution. Incorporation of the alkaline earth metal cations onto the SAPO framework was achieved via liquid state ion exchange, coupled partial detemplation/solid-state ion exchange, and combination of both techniques. MAS NMR revealed that the level of ion exchange was limited by the presence of protons and sodium cations near hexagonal prisms (site SI), which are relatively difficult to exchange with the alkaline earth metal due to steric and charge repulsion criteria. In addition, the presence of ammonium cations in the supercages facilitated the exchange of otherwise tenacious hydrogen as corroborated by unit cell compositional data as well as enhanced CO 2 adsorption at low partial pressures. The extraframework ammonium species were produced from partial detemplation of the structure-directing agent employed for the SAPO-34 synthesis, tetraethylammonium. - Graphical abstract: MAS NMR was used to elucidate the position the cationic species in alkaline earth metal exchanged silicoaluminophosphates. These species played a significant role during the ion exchange process and, therefore, the materials ultimate CO 2 adsorption performance. Highlights: ► Location of extraframework Sr 2+ or Ba 2+ cations was estimated by means of 1 H and 23 Na MAS NMR. ► Level of Sr 2+ or Ba 2+ ion exchange was limited by the presence of protons and sodium cations. ► Presence of ammonium cations in the supercages facilitated the exchange. ► Sr 2+ and Ba 2+ ion exchanged SAPOs are outstanding CO 2 adsorbents.

  13. A MAS NMR and DRIFT study of the Ga species in Ga/H-ZSM5 catalysts and their effect on propane ammoxidation

    Energy Technology Data Exchange (ETDEWEB)

    Pal, P. [Indian Inst. of Petroleum, Dehradun (India). Catalysis Division; Quartararo, J. [Liverpool Univ., Liverpool (United Kingdom). Leverhulme Centre for Innovative Catalysis, Dept. of Chemistry; Abd Hamid, S.B. [Malaya Univ., Postgraduate School, Bangunan (Malaysia); Derouane, E.G. [Algarve Univ., Faro (Portugal). Faculdade de Ciencias e Tecnologia; Vedrine, J.C. [Laboratoire de Physico-Chimie des Surface, Paris (France). Faculdade de Ciencias e Tecnologia; Magusin, P.C.M.M.; Anderson, B.G. [Eindhoven Univ. of Technology, Eindhoven (Netherlands). Schuit Institute of Catalysis

    2005-07-01

    This paper presents the results of a study that sought information about the nature and environment of the gallium (Ga) species in Ga/H-ZSM5 zeolites following H{sub 2}-O{sub 2} redox treatments applied during their activation by use of magic-angle spinning (MAS) {sup 71}Ga, {sup 27}Al, and {sup 29}Si NMR spectroscopy (Ga coordination) complemented by diffuse reflectance FT IR (DRIFT) spectroscopy (Bronsted acidity). This information was then correlated with their catalytic behavior for the ammoxidation of propane. Ga species were observed in several environments: octahedrally coordinated gallium in small Ga{sub 2}O{sub 3} particles at the external surface of the zeolite crystals; octahedrally coordinated gallium in GaO(OH) or related species; and tetrahedrally coordinated gallium in cationic-exchange positions inside the zeolite. Redox (H{sub 2}-O{sub 2}) cycles promote the migration of gallium from the GaO(OH) or Ga{sub 2}O{sub 3} species at the external surface of the zeolite crystals to cationic-exchange sites within the zeolite channels. It was concluded that the redox treatment had a beneficial effect on its catalytic performance for the ammoxidation of propane, which occurs via a bifunctional mechanism. The main product was acetonitrile at high gallium and aluminium contents. It was suggested that higher yields in acrylonitrile could be obtained through Ga-modified zeolites with a higher gallium and lower aluminium content. 22 refs., 1 tab., 6 figs.

  14. Evidence for radiation induced crosslinking in polytetrafluoroethylene by means of high-resolution solid-state 19F high-speed MAS NMR

    International Nuclear Information System (INIS)

    Katoh, Etsuko; Sugisawa, Hisashi; Oshima, Akihiro; Tabata, Yoneho; Seguchi, Tadao; Yamazaki, Toshimasa

    1999-01-01

    Radiation effects on molecular structure of polytetrafluoroethylene (PTFE) were studied by high-resolution solid-state 19 F high speed magic angle spinning (HS MAS) NMR spectroscopy. Samples used for the NMR studies were prepared by electron beam irradiation of PTFE with a wide range of irradiation doses from 0.5-10 MGy in the molten state at 340 deg. C under oxygen-free atmosphere. While the non-irradiated PTFE displayed only an intense peak of the internal CF 2 , several new signals corresponding to CF 3 , CF 2 and CF groups were observed for the PTFE which was high temperature irradiated at 340 deg. C in oxygen-free atmosphere (hti-PTFE). Intensities of these new signals increased with an increase of irradiation dose. The present solid-state 19 F HS MAS NMR studies provide not only the first experimental evidence regarding the existence of crosslinking structure in hti-PTFE, directly detected as the CF signal, but also the crosslinking density which can be estimated from a proportion of the CF versus total fluorine signal intensities. The higher the irradiation dose, the higher the crosslinking density; hti-PTFE with 10 MGy contains one crosslinking site per approximately 24 CF 2 groups, while the hti-PTFE with 5 MGy contains one crosslinking site per approximately 36 CF 2 groups. Further, G value of crosslinking (G(x)) was estimated from the signal intensities of 19 F HS MAS NMR spectra. The highest G(x)-value, 1.85, was observed for the 2MGy hti-PTFE sample, suggesting that crosslinking of PTFE is formed most efficaciously with 2 MGy irradiation in the molten state at 340 deg. C under oxygen-free atmosphere

  15. High field 27Al MAS NMR and TPD studies of active sites in ethanol dehydration using thermally treated transitional aluminas as catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Jian Zhi; Xu, Suochang; Kwak, Ja Hun; Hu, Mary Y.; Wan, Chuan; Zhao, Zhenchao; Szanyi, Janos; Bao, Xinhe; Han, Xiuwen; Wang, Yong; Peden, Charles H. F.

    2016-04-01

    Gamma-, sigma- and theta-Al2O3 are well known metastable “transitional” alumina structural polymorphs. Upon heating, Al2O3 transitions to the so-called and Al2O3 polymorphs and finally forms the thermally stable Al2O3. The poorly developed crystallinity and co-existence of the , , and Al2O3 prior to forming all Al2O3, making it difficult to characterize the structures as well as to quantify the various phases of the transition alumina. As a result, there are significant controversies in the literatures. In this work, a detailed NMR analysis was carried out at high magnetic field on three special aluminum oxide samples where the, , , Al2O3 phases are made dominant, respectively, by controlling the synthesis conditions. The goal is to simplify, including making unambiguous, spectral assignments in 27Al MAS NMR spectra of transition alumina that have not yet been commonly agreed previously. Specifically, quantitative 1D 27Al MAS NMR was used to quantify the ratios of the different alumina structural units, 2D MQMAS 27Al MAS was used for obtaining the highest spectral resolution to guide the analysis of the 1D spectrum, and a saturation pulse sequence was integrated into the 1D NMR to select the amorphous structures, including obtain spectra where the penta-coordinate sites are observed with enhanced relative intensity. Collectively, this study uniquely assigns Al-peaks (both octahedral and tetrahedral) to the Al2O3 and the Al2O3 phases and offers a new way of understanding, including quantifying, the different structural units and sites in transition alumina samples.

  16. Obtaining aluminas from the thermal decomposition of their different precursors: An {sup 27}Al MAS NMR and X-ray powder diffraction studies

    Energy Technology Data Exchange (ETDEWEB)

    Chagas, L.H.; De Carvalho, G.S.G. [Universidade Federal de Juiz de Fora, Departamento de Química, Grupo de Físico-Química de Sólidos e Interfaces, 36036-330 Juiz de Fora, MG (Brazil); San Gil, R.A.S. [Universidade Federal do Rio de Janeiro, Instituto de Química, 21949-900 Rio de Janeiro, RJ (Brazil); Chiaro, S.S.X. [PETROBRAS-CENPES, 21941-915 Rio de Janeiro, RJ (Brazil); Leitão, A.A. [Universidade Federal de Juiz de Fora, Departamento de Química, Grupo de Físico-Química de Sólidos e Interfaces, 36036-330 Juiz de Fora, MG (Brazil); Diniz, R., E-mail: renata.diniz@ufjf.edu.br [Universidade Federal de Juiz de Fora, Departamento de Química, Grupo de Físico-Química de Sólidos e Interfaces, 36036-330 Juiz de Fora, MG (Brazil)

    2014-01-01

    Graphical abstract: - Highlights: • We synthesized three precursors of alumina from different methods. • The calcination of the precursors generated several alumina polymorphs. • XRD and NMR were used for structural investigation of the polymorphs. • The synthesis route determines the structural and textural properties of the solids. - Abstract: A commercial sample of Boehmite was used as precursor of alumina polymorphs. For comparison, three other precursors were synthesized from different methods. Particularly, the use of excess of urea promoted a very crystalline form of basic aluminum carbonate. The characteristics of the four precursors were investigated by thermal, vibrational and X-ray powder diffraction (XRD) analysis. Additionally, the nuclear magnetic resonance, with magic angle spinning ({sup 27}Al MAS NMR), was used to verify the coordination of aluminum cations. Each precursor was calcined at various temperatures generating alumina polymorphs, which were structurally analyzed by XRD and {sup 27}Al MAS NMR. Due to interest in catalysis supports, special attention was given to the γ-Al{sub 2}O{sub 3} phase, which in addition to structural investigation was subjected to textural analysis. The results showed that, from different synthesis procedures and common route of calcination, one can obtain materials with the same composition but with different structural and textural properties, which in turn can significantly influence the performance of a supported catalyst.

  17. Observation of immobile regions in natural rubber at ambient temperature by solid-state C-13 CP/MAS NMR spectroscopy

    DEFF Research Database (Denmark)

    Larsen, F.H.; Rasmussen, T.; Pedersen, Walther Batsberg

    1999-01-01

    Employing C-13 CP/MAS NMR spectroscopy, the existence of immobile regions in natural rubber (cis-1,4-polyisoprene) corresponding to a few percent of the monomer units has been detected at ambient temperature. For synthetic rubbers no immobile regions have been detected at all. Applying different...... physical and chemical treatments to natural rubber it is shown that mastication, gamma-irradiation, and increasing the temperature, slightly above the ambient, reduce the amount of immobile regions. (C) 1999 Elsevier Science Ltd. All rights reserved....

  18. Fate of [15N]glycine in peat as determined by 13C and 15N CP-MAS NMR spectroscopy

    International Nuclear Information System (INIS)

    Benzing-Purdie, L.M.; Cheshire, M.V.; Williams, B.L.; Sparling, G.P.; Ratcliffe, C.I.; Ripmeester, J.A.

    1986-01-01

    Peat samples, nonsterile, sterilized by γ irradiation or autoclaving, were incubated with [ 15 N]glycine for a period of 6 months. The 13 C NMR data showed the established trend of increased humification with decreasing particle size and that autoclaving had significantly disturbed the humification-particle size distribution. The 15 N CP-MAS NMR spectra showed the presence of [ 15 N]glycine in all fractions after incubation. 15 NH 4 + , a result of either biological or chemical deamination, was one of the main products in the nonsterile peat series. The 15 N spectra also showed resonances corresponding to amine, secondary amide, and pyrrole-type nitrogen and the presence of glycine derivatives and melanoidins. The results presented give the first spectroscopic evidence of the possible involvement of the Maillard reaction in the humification process

  19. 1H line width dependence on MAS speed in solid state NMR - Comparison of experiment and simulation

    Science.gov (United States)

    Sternberg, Ulrich; Witter, Raiker; Kuprov, Ilya; Lamley, Jonathan M.; Oss, Andres; Lewandowski, Józef R.; Samoson, Ago

    2018-06-01

    Recent developments in magic angle spinning (MAS) technology permit spinning frequencies of ≥100 kHz. We examine the effect of such fast MAS rates upon nuclear magnetic resonance proton line widths in the multi-spin system of β-Asp-Ala crystal. We perform powder pattern simulations employing Fokker-Plank approach with periodic boundary conditions and 1H-chemical shift tensors calculated using the bond polarization theory. The theoretical predictions mirror well the experimental results. Both approaches demonstrate that homogeneous broadening has a linear-quadratic dependency on the inverse of the MAS spinning frequency and that, at the faster end of the spinning frequencies, the residual spectral line broadening becomes dominated by chemical shift distributions and susceptibility effects even for crystalline systems.

  20. Yeast-expressed human membrane protein aquaporin-1 yields excellent resolution of solid-state MAS NMR spectra

    International Nuclear Information System (INIS)

    Emami, Sanaz; Fan Ying; Munro, Rachel; Ladizhansky, Vladimir; Brown, Leonid S.

    2013-01-01

    One of the biggest challenges in solid-state NMR studies of membrane proteins is to obtain a homogeneous natively folded sample giving high spectral resolution sufficient for structural studies. Eukaryotic membrane proteins are especially difficult and expensive targets in this respect. Methylotrophic yeast Pichia pastoris is a reliable producer of eukaryotic membrane proteins for crystallography and a promising economical source of isotopically labeled proteins for NMR. We show that eukaryotic membrane protein human aquaporin 1 can be doubly ( 13 C/ 15 N) isotopically labeled in this system and functionally reconstituted into phospholipids, giving excellent resolution of solid-state magic angle spinning NMR spectra.

  1. CP/MAS 13C NMR characterization of the isomeric states and intermolecular packing in tris(8-hydroxyquinoline) aluminum(III) (Alq3).

    Science.gov (United States)

    Kaji, Hironori; Kusaka, Yasunari; Onoyama, Goro; Horii, Fumitaka

    2006-04-05

    The isomeric states and intermolecular packing of tris(8-hydroxyquinoline) aluminum(III) (Alq(3)) in the alpha-, gamma-, and delta-crystalline forms and in the amorphous state, which are important for understanding the light-emitting and electron-transport properties, have been analyzed by CP/MAS (13)C NMR. This simple NMR experiment shows that the isomeric state of alpha- and amorphous Alq(3) is meridional, whereas that of gamma- and delta-Alq(3) is facial. In the amorphous Alq(3), the inclusion of facial isomers has been under debate. Our experiments show that meridional isomers are dominant in the amorphous Alq(3), although the existence of facial isomers cannot be completely denied. The local structure of amorphous Alq(3) is similar to that of alpha-Alq(3) and is significantly different from those of gamma- and delta-Alq(3). Among these Alq(3) samples, the effect of intermolecular interaction is not found only for gamma-Alq(3). This finding can explain the good solvent solubility of gamma-Alq(3), compared with the other crystalline forms. It is also shown that the structures are locally disordered not only for amorphous Alq(3) but also for alpha-Alq(3), although clear X-ray diffraction peaks are observed for alpha-Alq(3). In contrast, the local structures of gamma- and delta-Alq(3) are well defined. A clear relation is found between the spectral patterns of CP/MAS (13)C NMR and the fluorescence wavelengths; the samples, which consist of facial isomers, show blue-shifted fluorescence compared with those of meridionals.

  2. Characterizing crystal disorder of trospium chloride: a comprehensive, 13C CP/MAS NMR, DSC, FTIR, and XRPD study

    Czech Academy of Sciences Publication Activity Database

    Urbanová, Martina; Šturcová, Adriana; Brus, Jiří; Beneš, Hynek; Skořepová, E.; Kratochvíl, B.; Čejka, J.; Šeděnková, Ivana; Kobera, Libor; Policianová, Olivia; Šturc, A.

    2013-01-01

    Roč. 102, č. 4 (2013), s. 1235-1248 ISSN 0022-3549 R&D Projects: GA ČR GPP106/11/P426 Institutional support: RVO:61389013 Keywords : trospium chloride * solid state NMR * factor analysis Subject RIV: FR - Pharmacology ; Medidal Chemistry Impact factor: 3.007, year: 2013

  3. CP/MAS ¹³C NMR study of pulp hornification using nanocrystalline cellulose as a model system.

    Science.gov (United States)

    Idström, Alexander; Brelid, Harald; Nydén, Magnus; Nordstierna, Lars

    2013-01-30

    The hornification process of paper pulp was investigated using solid-state (13)C NMR spectroscopy. Nanocrystalline cellulose was used to serve as a model system of the crystalline parts of the fibrils in pulp fibers. Characterization of the nanocrystalline cellulose dimensions was carried out using scanning electron microscopy. The samples were treated by drying and wetting cycles prior to NMR analysis where the hornification phenomenon was recorded by spectral changes of the cellulose C-4 carbon signals. An increase of the crystalline signal and a decrease of the signals corresponding to the accessible amorphous domains were found for both paper pulp and nanocrystalline cellulose. These spectral changes grew stronger with repeating drying and wetting cycles. The results show that cellulose co-crystallization contribute to hornification. Another conclusion is that the surfaces of higher hydrophobicity in cellulose fibrils have an increased preference for aggregation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Acidic properties of SSZ-33 and SSZ-35 novel zeolites: a complex infrared and MAS NMR study

    Czech Academy of Sciences Publication Activity Database

    Gil, B.; Zones, S. I.; Hwang, S.-J.; Voláková, Martina; Čejka, Jiří

    2008-01-01

    Roč. 112, č. 8 (2008), s. 2997-3007 ISSN 1932-7447 R&D Projects: GA ČR GA104/07/0383; GA AV ČR 1QS400400560 Institutional research plan: CEZ:AV0Z40400503 Keywords : nuclear magnetic resonance * adsorbed probe molecules * angle- spinning NMR Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.396, year: 2008

  5. Transitions in Al Coordination during Gibbsite Crystallization Using High-Field 27 Al and 23 Na MAS NMR Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Jian Zhi [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Zhang, Xin [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Jaegers, Nicholas R. [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Washington State University, Pullman, Washington 99164, United States; Wan, Chuan [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Graham, Trent R. [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Washington State University, Pullman, Washington 99164, United States; Hu, Mary [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Pearce, Carolyn I. [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Felmy, Andrew R. [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Washington State University, Pullman, Washington 99164, United States; Clark, Sue B. [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Washington State University, Pullman, Washington 99164, United States; Rosso, Kevin M. [Pacific Northwest National Laboratory, Richland, Washington 99354, United States

    2017-11-30

    Mechanisms of nucleation and growth of Al hydroxides such as gibbsite from aqueous solution, particularly in highly alkaline conditions, remain poorly understood. In this work, quantitative 27Al and 22Na MAS NMR experiments were conducted on solid samples extracted from the crystallization of gibbsite from an amorphous aluminum hydroxide gel precursor. The use of high magnetic field and fast sample spinning allowed transitional tetrahedral (AlT) and pentahedral (AlP) aluminum species to be observed along with the octahedral aluminum (AlO) that dominates the gibbsite product. Low-coordinated Al species could be detected at concentrations as low as 0.1% of the total Al sites. It is established that (a) AlT and AlP coexist on the surface of growing gibbsites even with a combined percentage over the total Al sites of less than 1%; (b) Different synthesis methods generate gibbsite with varying amounts of low-coordinated Al; (c) the amorphous gel precursor contains a significant amount of low-coordinated Al sites with AO: AlP: AlT ratios of approximately 4:2:1; (d) upon hydration, the external, low-coordinated Al sites become six-fold coordinated by interacting with the oxygen in H2O and the 27Al MAS NMR peak position shifts to that for the AlO sites; (e) gibbsite with increased long range order is synthesized over longer times by gradually incorporating residual AlP and AlT sites into octahedrally-coordinated AlO sites; (f) trace Na is predominantly a surface species on gibbsite particles. These findings provide a basis for understanding the gibbsite crystallization mechanism, along with a general means of characterizing gibbsite surface properties that are of equal importance for understanding related processes such as dissolution behavior.

  6. Solid state CP/MAS 13C n.m.r. analysis of particle size and density fractions of soil incubated with uniformly labelled 13C-glucose

    International Nuclear Information System (INIS)

    Baldock, J.A.; Oades, J.M.

    1990-01-01

    A soil incubated for 34 days in the absence (control) and presence (treated) of uniformly labelled 13 C-glucose was dispersed using an ultrasonic probe and fractionated by sedimentation in water and a polytungstate solution of density 2.0 Mg m -3 . Solid state CP/MAS 13 C n.m.r. (cross polarization/magic angle spinning 13 C nuclear magnetic resonance) spectroscopy was used to characterize the chemical structure of the native soil organic carbon and the residual substrate carbon in the fractions of the control and treated soils. To obtain quantitative results it was essential to determine the spin lattice relaxation time in a rotating frame of the individual carbon types in the spectra as the relaxation behaviour of the native organic material in the clay fraction was different from that of the residual substrate carbon. The residual substrate carbon was found to accumulate in predominantly alkyl and O-alkyl structures in both fractions. However, significant amounts of acetal and carboxyl carbon were also observed in the clay fraction. Little if any aromatic or phenolic carbon was synthesized by the soil microorganisms utilizing substrate carbon. Dipolar dephasing CP/MAS 13 C n.m.r. experiments were also performed and allowed the proportion of each type of carbon which was protonated and nonprotonated to be estimated. Essentially all of the O-alkyl and acetal carbon, 25-40% of the aromatic carbon and 66-80% of the alkyl carbon was protonated in the fractions isolated from the treated soil. 24 refs., 4 figs., 2 tabs

  7. Metallic nature of Sn{sub 1-} {sub x} Sb {sub x} O{sub 2{+-}} {sub {delta}} (x=0.0, 0.10 and 0.20) mixed oxides: Probed by {sup 119}Sn MAS NMR

    Energy Technology Data Exchange (ETDEWEB)

    Jayakumar, O.D. [Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)]. E-mail: ddjaya@apsara.barc.ernet.in; Sudarsan, V. [Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Kulshreshtha, S.K. [Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    2007-04-15

    Antimony doped SnO{sub 2} samples were prepared by co-precipitation method and characterized by X-ray diffraction (XRD), {sup 119}Sn magic angle spinning nuclear magnetic resonance (MAS NMR) and variable temperature electrical conductivity measurements. Based on {sup 119}Sn MAS NMR measurements on these samples, it was established that only above 400 deg. C, the structural units of antimony and tin interacts, resulting in the metallic nature. Metallic behavior of the high-temperature heated samples was further confirmed by the variable temperature electrical conductivity measurements.

  8. Solubilization and localization of weakly polar lipids in unsonicated egg phosphatidylcholine: A 13C MAS NMR study

    International Nuclear Information System (INIS)

    Hamilton, J.A.; Fujito, D.T.; Hammer, C.F.

    1991-01-01

    The weakly polar lipids cholesteryl ester, triacylglycerol, and diacylglycerol incorporate to a limited extent into the lamellar structure of small unilamellar vesicles. The localization of the carbonyl group(s) at the aqueous interface was detected by [ 13 C]carbonyl chemical shift changes relative to the neat unhydrated lipid. This study uses 13 C NMR to investigate the interactions of thes lipids with unsonicated (multilamellar) phosphatidylcholine, a model system for cellular membranes and surfaces of emulsion particles with low curvature. Magic angle spinning reduced the broad lines of the unsonicated dispersions to narrow lines comparable to those from sonicated dispersions. [ 13 C]Carbonyl chemical shifts revealed incorporation of the three lipids into the lamellar structure of the unsonicated phospholipids and a partial hydration of the carbonyl groups similar to that observed in small vesicles. Other properties of interfacial weakly polar lipids in multilayers were similar to those in small unilamellar bilayers. There is thus a general tendency of weakly polar lipids to incorparate at least to a small extent into the lamellar structure of phospholipids and take on interfacial properties that are distinct from their bulk-phase properties. This pool of surface-located lipid is likely to be directly involved in enzymatyic transformations and protein-mediated transport. The 13 C magic angle spinning NMR method may be generally useful for determining the orientation of molecules in model membranes

  9. Indirectly detected chemical shift correlation NMR spectroscopy in solids under fast magic angle spinning

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Kanmi [Iowa State Univ., Ames, IA (United States)

    2011-01-01

    The development of fast magic angle spinning (MAS) opened up an opportunity for the indirect detection of insensitive low-γ nuclei (e.g., 13C and 15N) via the sensitive high-{gamma} nuclei (e.g., 1H and 19F) in solid-state NMR, with advanced sensitivity and resolution. In this thesis, new methodology utilizing fast MAS is presented, including through-bond indirectly detected heteronuclear correlation (HETCOR) spectroscopy, which is assisted by multiple RF pulse sequences for 1H-1H homonuclear decoupling. Also presented is a simple new strategy for optimization of 1H-1H homonuclear decoupling. As applications, various classes of materials, such as catalytic nanoscale materials, biomolecules, and organic complexes, are studied by combining indirect detection and other one-dimensional (1D) and two-dimensional (2D) NMR techniques. Indirectly detected through-bond HETCOR spectroscopy utilizing refocused INEPT (INEPTR) mixing was developed under fast MAS (Chapter 2). The time performance of this approach in 1H detected 2D 1H{l_brace}13C{r_brace} spectra was significantly improved, by a factor of almost 10, compared to the traditional 13C detected experiments, as demonstrated by measuring naturally abundant organic-inorganic mesoporous hybrid materials. The through-bond scheme was demonstrated as a new analytical tool, which provides complementary structural information in solid-state systems in addition to through-space correlation. To further benefit the sensitivity of the INEPT transfer in rigid solids, the combined rotation and multiple-pulse spectroscopy (CRAMPS) was implemented for homonuclear 1H decoupling under fast MAS (Chapter 3). Several decoupling schemes (PMLG5m$\\bar{x}$, PMLG5mm$\\bar{x}$x and SAM3) were analyzed to maximize the performance of through-bond transfer based

  10. Analysis of mercerization process based on the intensity change of deconvoluted resonances of 13C CP/MAS NMR: Cellulose mercerized under cooling and non-cooling conditions

    International Nuclear Information System (INIS)

    Miura, Kento; Nakano, Takato

    2015-01-01

    The area intensity change of C1, C4, and C6 in spectrum obtained by 13 C CP/MAS NMR and the mutual relationship between their changes were examined for cellulose samples treated with various concentrations of aqueous NaOH solutions under non-cooling and cooling conditions. The area intensity of C1-up and C6-down changed cooperatively with that of C4-down which corresponds to the crystallinity of samples: “-up” and “-down” are the up- and down- field component in a splitting peak of NMR spectrum, respectively. The intensity change of C1-up starts to decrease with decreasing in that of C4-down after that of C6-down is almost complete. These changes were more clearly observed for samples treated under cooling condition. It can be suggested that their characteristic change relates closely to the change in conformation of cellulose chains by induced decrystallization and the subsequent crystallization of cellulose II, and presumed that their changes at microscopic level relate to the macroscopic morphological changes such as contraction along the length of cellulose chains and recovery along the length. - Highlight: • Samples were mercerized at various NaOH concentrations under non-cooling and cooling. • The intensity change of C1 starts immediately after that of C6 is complete. • The creation of cell-II starts when decrystallization proceeds to a certain state. • This change relates closely to the change in conformation of cellulose chains. • The above change is more clearly found for samples treated under cooling

  11. Solid-state NMR covariance of homonuclear correlation spectra.

    Science.gov (United States)

    Hu, Bingwen; Amoureux, Jean-Paul; Trebosc, Julien; Deschamps, Michael; Tricot, Gregory

    2008-04-07

    Direct covariance NMR spectroscopy, which does not involve a Fourier transformation along the indirect dimension, is demonstrated to obtain homonuclear correlation two-dimensional (2D) spectra in the solid state. In contrast to the usual 2D Fourier transform (2D-FT) NMR, in a 2D covariance (2D-Cov) spectrum the spectral resolution in the indirect dimension is determined by the resolution along the detection dimension, thereby largely reducing the time-consuming indirect sampling requirement. The covariance method does not need any separate phase correction or apodization along the indirect dimension because it uses those applied in the detection dimension. We compare in detail the specifications obtained with 2D-FT and 2D-Cov, for narrow and broad resonances. The efficiency of the covariance data treatment is demonstrated in organic and inorganic samples that are both well crystallized and amorphous, for spin -1/2 nuclei with 13C, 29Si, and 31P through-space or through-bond homonuclear 2D correlation spectra. In all cases, the experimental time has been reduced by at least a factor of 10, without any loss of resolution and signal to noise ratio, with respect to what is necessary with the 2D-FT NMR. According to this method, we have been able to study the silicate network of glasses by 2D NMR within reasonable experimental time despite the very long relaxation time of the 29Si nucleus. The main limitation of the 2D-Cov data treatment is related to the introduction of autocorrelated peaks onto the diagonal, which does not represent any actual connectivity.

  12. Effects of solvent concentration and composition on protein dynamics: 13C MAS NMR studies of elastin in glycerol-water mixtures.

    Science.gov (United States)

    Demuth, Dominik; Haase, Nils; Malzacher, Daniel; Vogel, Michael

    2015-08-01

    We use (13)C CP MAS NMR to investigate the dependence of elastin dynamics on the concentration and composition of the solvent at various temperatures. For elastin in pure glycerol, line-shape analysis shows that larger-scale fluctuations of the protein backbone require a minimum glycerol concentration of ~0.6 g/g at ambient temperature, while smaller-scale fluctuations are activated at lower solvation levels of ~0.2 g/g. Immersing elastin in various glycerol-water mixtures, we observe at room temperature that the protein mobility is higher for lower glycerol fractions in the solvent and, thus, lower solvent viscosity. When decreasing the temperature, the elastin spectra approach the line shape for the rigid protein at 245 K for all studied samples, indicating that the protein ceases to be mobile on the experimental time scale of ~10(-5) s. Our findings yield evidence for a strong coupling between elastin fluctuations and solvent dynamics and, hence, such interaction is not restricted to the case of protein-water mixtures. Spectral resolution of different carbon species reveals that the protein-solvent couplings can, however, be different for side chain and backbone units. We discuss these results against the background of the slaving model for protein dynamics. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Fast MAS 1H NMR Study of Water Adsorption and Dissociation on the (100) Surface of Ceria Nanocubes: A Fully Hydroxylated, Hydrophobic Ceria Surface

    Energy Technology Data Exchange (ETDEWEB)

    Gill, Lance [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division; Beste, Ariana [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Joint Institute for Computational Sciences (JIBS); Univ. of Tennessee, Knoxville, TN (United States); Chen, Banghao [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division; Li, Meijun [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division; Mann, Amanda K. P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division; Overbury, Steven H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division; Hagaman, Edward W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division

    2017-03-22

    1H nuclear magnetic resonance (NMR) spectroscopy was used to study hydroxylic surface species on ceria nanocubes, a crystalline, high-surface-area CeO2 that presents mostly (100) facets. Water adsorption and desorption experiments in combination with fast magic angle spinning (MAS, 20–40 kHz) 1H NMR provide high-resolution 1H spectra that allow the observation of ten resonance bands (water or hydroxyl) on or under the (100) surface. Assignments were made using a combination of adsorption and temperature-programmed desorption, quantitative spin counting, deuterium exchange, spin–lattice (T1) and spin–spin (T2) relaxation, and DFT calculations. In air, the (100) surface exists as a fully hydroxylated surface. Water adsorption and dissociation on dry ceria surfaces occur first at oxygen vacancies, but Ce3+ centers are not required since water dissociation is barrier-less on the fully oxidized surface. Surface $-$OH functionality occurs in two resolved bands representing isolated $-$OH (1 ppm) and hydrogen-bonded $-$OH (9 ppm), the latter being dominant. Deuterium exchange of surface hydroxyls with D2O does not occur under mild or forcing conditions. Despite large differences in the T1 of surface hydroxyls and physisorbed water, surface hydroxyl T1 values are independent of the presence or absence of physisorbed water, demonstrating that the protons within these two functional group pools are not in intimate contact. These observations show that, once hydroxylated, the surface $-$OH functionality preferentially forms hydrogen bonds with surface lattice oxygen, i.e., the hydroxylated (100) surface of ceria is hydrophobic. Near this surface it is energetically more favorable for physisorbed water to hydrogen bond to itself rather than to the surface. DFT calculations support this notion. Impurity Na+ remaining in incompletely washed ceria nanocubes

  14. Effect of Ge/Si substitutions on the local geometry of Si framework sites in zeolites: A combined high resolutionsup29/supSi MAS NMR and DFT/MM study on zeolite Beta polymorph C (BEC)

    Czech Academy of Sciences Publication Activity Database

    Whittleton, Sarah R.; Vicente, A.; Fernandez, C.; Rastegar, Somayeh F.; Fishchuk, Anna V.; Sklenák, Štěpán

    2018-01-01

    Roč. 267, SEP 2018 (2018), s. 124-133 ISSN 1387-1811 R&D Projects: GA ČR(CZ) GA15-14007S Grant - others:Ga MŠk(CZ) LM2015070 Institutional support: RVO:61388955 Keywords : 29 Si MAS NMR * bec * Ge-zeolites * Germanoaluminosilicates * Zeolite Beta polymorph C Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 3.615, year: 2016

  15. {sup 1}H and {sup 23}Na MAS NMR spectroscopy of cationic species in CO{sub 2} selective alkaline earth metal porous silicoaluminophosphates prepared via liquid and solid state ion exchange

    Energy Technology Data Exchange (ETDEWEB)

    Arevalo-Hidalgo, Ana G. [Department of Chemical Engineering, University of Puerto Rico-Mayagueez Campus, Mayagueez, PR 00681-9000 (Puerto Rico); Dugar, Sneha; Fu, Riqiang [National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310 (United States); Hernandez-Maldonado, Arturo J., E-mail: arturoj.hernandez@upr.edu [Department of Chemical Engineering, University of Puerto Rico-Mayagueez Campus, Mayagueez, PR 00681-9000 (Puerto Rico)

    2012-07-15

    The location of extraframework cations in Sr{sup 2+} and Ba{sup 2+} ion-exchanged SAPO-34 was estimated by means of {sup 1}H and {sup 23}Na MAS NMR spectroscopy and spectral deconvolution. Incorporation of the alkaline earth metal cations onto the SAPO framework was achieved via liquid state ion exchange, coupled partial detemplation/solid-state ion exchange, and combination of both techniques. MAS NMR revealed that the level of ion exchange was limited by the presence of protons and sodium cations near hexagonal prisms (site SI), which are relatively difficult to exchange with the alkaline earth metal due to steric and charge repulsion criteria. In addition, the presence of ammonium cations in the supercages facilitated the exchange of otherwise tenacious hydrogen as corroborated by unit cell compositional data as well as enhanced CO{sub 2} adsorption at low partial pressures. The extraframework ammonium species were produced from partial detemplation of the structure-directing agent employed for the SAPO-34 synthesis, tetraethylammonium. - Graphical abstract: MAS NMR was used to elucidate the position the cationic species in alkaline earth metal exchanged silicoaluminophosphates. These species played a significant role during the ion exchange process and, therefore, the materials ultimate CO{sub 2} adsorption performance. Highlights: Black-Right-Pointing-Pointer Location of extraframework Sr{sup 2+} or Ba{sup 2+} cations was estimated by means of {sup 1}H and {sup 23}Na MAS NMR. Black-Right-Pointing-Pointer Level of Sr{sup 2+} or Ba{sup 2+} ion exchange was limited by the presence of protons and sodium cations. Black-Right-Pointing-Pointer Presence of ammonium cations in the supercages facilitated the exchange. Black-Right-Pointing-Pointer Sr{sup 2+} and Ba{sup 2+} ion exchanged SAPOs are outstanding CO{sub 2} adsorbents.

  16. IR and NMR spectroscopic correlation of enterobactin by DFT

    Science.gov (United States)

    Moreno, M.; Zacarias, A.; Porzel, A.; Velasquez, L.; Gonzalez, G.; Alegría-Arcos, M.; Gonzalez-Nilo, F.; Gross, E. K. U.

    2018-06-01

    Emerging and re-emerging epidemic diseases pose an ongoing threat to global health. Currently, Enterobactin and Enterobactin derivatives have gained interest, owing to their potential application in the pharmaceutical field. As it is known [J. Am. Chem. Soc (1979) 101, 20, 6097-6104], Enterobactin (H6EB) is an efficient iron carrier synthesized and secreted by many microbial species. In order to facilitate the elucidation of enterobactin and its analogues, here we propose the creation of a H6EB standard set using Density Functional Theory Infrared (IR) and NMR spectra. We used two exchange-correlation (xc) functionals (PBE including long-range corrections sbnd LC-PBEsbnd and mPW1), 2 basis sets (QZVP and 6-31G(d)) and 2 grids (fine and ultrafine) for most of the H6EB structures dependent of dihedral angles. The results show a significant difference between the Osbnd H and Nsbnd H bands, while the Cdbnd O amide and Osbnd (Cdbnd O)sbnd IR bands are often found on top of each other. The NMR DFT calculations show a strong dependence on the xc functional, basis set, and grid used for the H6EB structure. Calculated 1H and 13C NMR spectra enable the effect of the solvent to be understood in the context of the experimental measurements. The good agreement between the experimental and the calculated spectra using LC-PBE/QZVP and ultrafine grid suggest the possibility of the systems reported here to be considered as a standard set. The dependence of electrostatic potential and frontier orbitals with the catecholamide dihedral angles of H6EB is described. The matrix-assisted laser desorption/ionization time of the flight mass spectrometry (MALDI-TOF MS) of H6EB is also reported of manner to enrich the knowledge about its reactivity.

  17. One-Pot Synthesis, X-Ray Diffraction and MAS NMR Spectroscopic Study of Gallosilicate Nitrate Cancrinite Na8[GaSiO4]6(NO34(H2O6

    Directory of Open Access Journals (Sweden)

    Ashok V. Borhade

    2010-01-01

    Full Text Available One-pot synthetic gallosilicate nitrate cancrinite (CAN framework topology have been synthesized under hydrothermal conditions at 100 °C. The synthesized product was characterized by, X-ray powder diffraction, IR, Raman and 29Si, 23Na MAS NMR spectroscopy, SEM and thermogravimetry. The crystal structure refinement of pure nitrate cancrinite has been carried out from X-ray data using Rietveld refinement method. Gallosilicate cancrinite Na8[GaSiO4]6(NO34(H2O6 crystalline hexagonal with space group P63 and a = 12.77981 Å (2, c = 5.20217 Å (1, (Rwp = 0.0696 Rp = 0.0527. The results by MAS NMR spectroscopy confirmed the alternating Si, Ga ordering of the gallosilicate framework for a Si/Ga ratio of 1.0. A distribution of the quadrupolar interaction of the sodium cations caused by the enclatherated water molecules and motional effects can be suggested from the 23Na MAS NMR. Thermogravimetric investigation shows the extent of nitrate entrapment, stability within the cancrinite cage and decomposition properties. SEM clearly shows the hexagonal needle shaped crystals of nitrate cancrinite.

  18. Phosphole complexes of Gold(I) halides: Comparison of solution and solid-state structures by a combination of solution and CP/MAS 31P NMR spectroscopy and x-ray crystallography

    International Nuclear Information System (INIS)

    Attar, S.; Nelson, J.H.; Bearden, W.H.; Alcock, N.W.; Alyea, E.C.

    1990-01-01

    A series of complexes of 1-phenyldibenzophosphole (DBP), 1-phenyl-3,4,-dimethylphosphole (DMPP), and triphenylphosphine of the type L n AuX (n = 1, L = DBP, DMPP, Ph 3 P, X = Cl, Br, I; n = 3, L = DBP, X = Cl, Br, I; n = 3, L = Ph 3 P, X = Cl; n = 4, L = DBP, DMPP, X = PF 6 ) have been prepared and characterized. The structures of (DBP)AuCl (1), (DBP) 3 AuCl (2), and (DMPP)AuCl (3) have been determined from three-dimensional x-ray data collected by counter methods. Crystal structure of the complexes is reported. The CP/MAS 31 P( 1 H) NMR spectrum of complex 1 shows two resonances in a 1:1 intensity ratio, and the CP/MAS 31 P( 1 H) NMR spectrum of complex 3 shows three resonances in a 1:1:1 intensity ratio for reasons that are not yet understood. Though the three phospholes are crystallographically inequivalent (d(AuP) = 2.359 (1), 2.382 (1), and 2.374 (2) angstrom) the molecule has effective C s symmetry as evidenced by the observation of two 31 P resonances in a 2:1 intensity ratio in its CP/MAS 31 P( 1 H) NMR spectrum. Variable-temperature 31 P( 1 H) NMR spectra obtained on solutions of LAuCl + L in various ratios were analyzed to determine the nature of the species present in solution and to gain information regarding their relative stabilities as a function of the nature of the phosphine. 79 refs., 8 figs., 9 tabs

  19. 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

  20. Analysis of local molecular motions of aromatic sidechains in proteins by 2D and 3D fast MAS NMR spectroscopy and quantum mechanical calculations

    Czech Academy of Sciences Publication Activity Database

    Paluch, P.; Pawlak, T.; Jeziorna, A.; Trébosc, J.; Hou, G.; Vega, A. J.; Amoureux, J. P.; Dračínský, Martin; Polenova, T.; Potrzebowski, M. J.

    2015-01-01

    Roč. 17, č. 43 (2015), s. 28789-28801 ISSN 1463-9076 R&D Projects: GA ČR GA15-11223S Institutional support: RVO:61388963 Keywords : solid-state NMR * angle spinning NMR * NMR Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.449, year: 2015 http://pubs.rsc.org/en/content/articlepdf/2015/cp/c5cp04475h

  1. Structure determination of uniformly {sup 13}C, {sup 15}N labeled protein using qualitative distance restraints from MAS solid-state {sup 13}C-NMR observed paramagnetic relaxation enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Tamaki, Hajime [Hokkaido University, Graduate School of Life Science (Japan); Egawa, Ayako [Osaka University, Institute for Protein Research (Japan); Kido, Kouki [Hokkaido University, Graduate School of Life Science (Japan); Kameda, Tomoshi [National Institute of Advanced Industrial Science and Technology, Biotechnology Research Institute for Drug Discovery (Japan); Kamiya, Masakatsu; Kikukawa, Takashi; Aizawa, Tomoyasu [Hokkaido University, Faculty of Advanced Life Science (Japan); Fujiwara, Toshimichi [Osaka University, Institute for Protein Research (Japan); Demura, Makoto, E-mail: demura@sci.hokudai.ac.jp [Hokkaido University, Faculty of Advanced Life Science (Japan)

    2016-01-15

    Magic angle spinning (MAS) solid-state nuclear magnetic resonance (NMR) is a powerful method for structure determination of insoluble biomolecules. However, structure determination by MAS solid-state NMR remains challenging because it is difficult to obtain a sufficient amount of distance restraints owing to spectral complexity. Collection of distance restraints from paramagnetic relaxation enhancement (PRE) is a promising approach to alleviate this barrier. However, the precision of distance restraints provided by PRE is limited in solid-state NMR because of incomplete averaged interactions and intermolecular PREs. In this report, the backbone structure of the B1 domain of streptococcal protein G (GB1) has been successfully determined by combining the CS-Rosetta protocol and qualitative PRE restraints. The derived structure has a Cα RMSD of 1.49 Å relative to the X-ray structure. It is noteworthy that our protocol can determine the correct structure from only three cysteine-EDTA-Mn{sup 2+} mutants because this number of PRE sites is insufficient when using a conventional structure calculation method based on restrained molecular dynamics and simulated annealing. This study shows that qualitative PRE restraints can be employed effectively for protein structure determination from a limited conformational sampling space using a protein fragment library.

  2. Heteronuclear 2D (1H-13C) MAS NMR Resolves the Electronic Structure of Coordinated Histidines in Light-Harvesting Complex II: Assessment of Charge Transfer and Electronic Delocalization Effect

    International Nuclear Information System (INIS)

    Matysik, Joerg; Boer, Ido de; Gast, Peter; Gorkom, Hans J. van; Groot, Huub J.M. de

    2004-01-01

    In a recent MAS NMR study, two types of histidine residues in the light-harvesting complex II (LH2) of Rhodopseudomonas acidophila were resolved: Type 1 (neutral) and Type 2 (positively charged) (Alia et al. J. Am. Chem. Soc.). The isotropic 13 C shifts of histidines coordinating to B850 BChl a are similar to fully positively charged histidine, while the 15 N shift anisotropy shows a predominantly neutral character. In addition the possibility that the ring currents are quenched by overlap in the superstructure of the complete ring of 18 B850 molecules in the LH2 complex could not be excluded. In the present work, by using two-dimensional heteronuclear ( 1 H- 13 C) dipolar correlation spectroscopy with phase-modulated Lee-Goldburg homonuclear 1 H decoupling applied during the t 1 period, a clear and unambiguous assignment of the protons of histidine interacting with the magnesium of a BChl a molecule is obtained and a significant ring current effect from B850 on the coordinating histidine is resolved. Using the ring current shift on 1 H, we refine the 13 C chemical shift assignment of the coordinating histidine and clearly distinguish the electronic structure of coordinating histidines from that of fully positively charged histidine. The DFT calculations corroborate that the coordinating histidines carry ∼0.2 electronic equivalent of positive charge in LH2. In addition, the data indicate that the ground state electronic structures of individual BChl a/His complexes is largely independent of supermolecular π interactions in the assembly of 18 B850 ring in LH2

  3. Dynamics-based selective 2D 1H/1H chemical shift correlation spectroscopy under ultrafast MAS conditions

    Science.gov (United States)

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy

    2015-05-01

    Dynamics plays important roles in determining the physical, chemical, and functional properties of a variety of chemical and biological materials. However, a material (such as a polymer) generally has mobile and rigid regions in order to have high strength and toughness at the same time. Therefore, it is difficult to measure the role of mobile phase without being affected by the rigid components. Herein, we propose a highly sensitive solid-state NMR approach that utilizes a dipolar-coupling based filter (composed of 12 equally spaced 90° RF pulses) to selectively measure the correlation of 1H chemical shifts from the mobile regions of a material. It is interesting to find that the rotor-synchronized dipolar filter strength decreases with increasing inter-pulse delay between the 90° pulses, whereas the dipolar filter strength increases with increasing inter-pulse delay under static conditions. In this study, we also demonstrate the unique advantages of proton-detection under ultrafast magic-angle-spinning conditions to enhance the spectral resolution and sensitivity for studies on small molecules as well as multi-phase polymers. Our results further demonstrate the use of finite-pulse radio-frequency driven recoupling pulse sequence to efficiently recouple weak proton-proton dipolar couplings in the dynamic regions of a molecule and to facilitate the fast acquisition of 1H/1H correlation spectrum compared to the traditional 2D NOESY (Nuclear Overhauser effect spectroscopy) experiment. We believe that the proposed approach is beneficial to study mobile components in multi-phase systems, such as block copolymers, polymer blends, nanocomposites, heterogeneous amyloid mixture of oligomers and fibers, and other materials.

  4. Dynamics-based selective 2D 1H/1H chemical shift correlation spectroscopy under ultrafast MAS conditions

    International Nuclear Information System (INIS)

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy

    2015-01-01

    Dynamics plays important roles in determining the physical, chemical, and functional properties of a variety of chemical and biological materials. However, a material (such as a polymer) generally has mobile and rigid regions in order to have high strength and toughness at the same time. Therefore, it is difficult to measure the role of mobile phase without being affected by the rigid components. Herein, we propose a highly sensitive solid-state NMR approach that utilizes a dipolar-coupling based filter (composed of 12 equally spaced 90° RF pulses) to selectively measure the correlation of 1 H chemical shifts from the mobile regions of a material. It is interesting to find that the rotor-synchronized dipolar filter strength decreases with increasing inter-pulse delay between the 90° pulses, whereas the dipolar filter strength increases with increasing inter-pulse delay under static conditions. In this study, we also demonstrate the unique advantages of proton-detection under ultrafast magic-angle-spinning conditions to enhance the spectral resolution and sensitivity for studies on small molecules as well as multi-phase polymers. Our results further demonstrate the use of finite-pulse radio-frequency driven recoupling pulse sequence to efficiently recouple weak proton-proton dipolar couplings in the dynamic regions of a molecule and to facilitate the fast acquisition of 1 H/ 1 H correlation spectrum compared to the traditional 2D NOESY (Nuclear Overhauser effect spectroscopy) experiment. We believe that the proposed approach is beneficial to study mobile components in multi-phase systems, such as block copolymers, polymer blends, nanocomposites, heterogeneous amyloid mixture of oligomers and fibers, and other materials

  5. Correlation of NMR and refractometry to evaluate the stability constant on carbon tetrachloride

    International Nuclear Information System (INIS)

    Modarress, H.; Pouryazadanpanah, N.

    2004-01-01

    An equation has been suggested which correlate the NMR and refractometry results to evaluate the stability constant of electron donor complexes. Using this equation the stability constant of complexation between carbon tetrachloride and toluene in cyclohexane has been studied by refractometry and NMR spectroscopy

  6. A study of the adsorption activities of silanol surface structures on a fused silica model substrate by combining 29Si CP MAS NMR and inverse gas chromatographic data

    NARCIS (Netherlands)

    Scholten, A.B.; Janssen, J.G.M.; Haan, de J.W.; Cramers, C.A.

    1994-01-01

    The possibilities of inverse gas-solid chromatog. (IGC) in obtaining chromatog. data on fumed silica were examd. Aerosil A-200, a fused silica model substrate in 29Si NMR anal., was trimethylsilylated to different degrees. IGC was used to vary reproducibly det. the free specific energies of

  7. Combined use of EPR and 23Na MAS NMR spectroscopy for assessing the properties of the mixed cobalt-nickel-manganese layers of P3-NayCo1-2xNixMnxO2.

    Science.gov (United States)

    Kalapsazova, M; Ivanova, S; Kukeva, R; Simova, S; Wegner, S; Zhecheva, E; Stoyanova, R

    2017-10-11

    Knowledge on the formation of mixed transition metal layers on lithium and sodium transition metal oxides, Li/Na(Co,Ni,Mn,)O 2 , determines the ability to control their electrochemical properties as electrode materials in alkaline ion batteries. Taking this into account, herein we combine the EPR and 23 Na MAS NMR spectroscopic techniques to gain insights into the structural peculiarities of the mixed cobalt-nickel-manganese layers of Na y Co 1-2x Ni x Mn x O 2 with a three-layer stacking (P3-type) structure. Two types of compositions are examined where diamagnetic Co 3+ and paramagnetic Ni 3+ and Mn 4+ are stabilized: Na 2/3 Co 1/3 Ni 1/3 Mn 1/3 O 2 and Na 1/2 Ni 1/2 Mn 1/2 O 2 . EPR spectroscopy operating in the X- and Q-band region is applied with an aim to improve the spectra resolution and, on the other hand, to provide straightforward information on the coordination of the transition metal ions inside the layers. The analysis of EPR spectra is based on the reference for the Mn 4+ and Ni 2+ ions occurring simultaneously in oxides with two layer stacking, P2-Na 2/3 Ni 1/3 Mn 2/3 O 2 . Complementary to EPR, 23 Na MAS NMR spectroscopy at high spinning rates is undertaken to assess the local structure of the Na nucleus in the layered P3-Na y Co 1-2x Ni x Mn x O 2 oxides. All results are discussed taking into account the EPR and NMR data for the well-known lithium analogues O3-LiCo 1/3 Ni 1/3 Mn 1/3 O 2 and O3-LiNi 1/2 Mn 1/2 O 2 . Finally, the structure peculiarities of the transition metal layers extracted from the EPR and NMR methods are demonstrated by electrochemical intercalation of Li + ions into P3-Na y Co 1-2x Ni x Mn x O 2 .

  8. Out-and-back {sup 13}C-{sup 13}C scalar transfers in protein resonance assignment by proton-detected solid-state NMR under ultra-fast MAS

    Energy Technology Data Exchange (ETDEWEB)

    Barbet-Massin, Emeline; Pell, Andrew J. [University of Lyon, CNRS/ENS Lyon/UCB Lyon 1, Centre de RMN a Tres Hauts Champs (France); Jaudzems, Kristaps [Latvian Institute of Organic Synthesis (Latvia); Franks, W. Trent; Retel, Joren S. [Leibniz-Institut fuer Molekulare Pharmakologie (Germany); Kotelovica, Svetlana; Akopjana, Inara; Tars, Kaspars [Biomedical Research and Study Center (Latvia); Emsley, Lyndon [University of Lyon, CNRS/ENS Lyon/UCB Lyon 1, Centre de RMN a Tres Hauts Champs (France); Oschkinat, Hartmut [Leibniz-Institut fuer Molekulare Pharmakologie (Germany); Lesage, Anne; Pintacuda, Guido, E-mail: guido.pintacuda@ens-lyon.fr [University of Lyon, CNRS/ENS Lyon/UCB Lyon 1, Centre de RMN a Tres Hauts Champs (France)

    2013-08-15

    We present here {sup 1}H-detected triple-resonance H/N/C experiments that incorporate CO-CA and CA-CB out-and-back scalar-transfer blocks optimized for robust resonance assignment in biosolids under ultra-fast magic-angle spinning (MAS). The first experiment, (H)(CO)CA(CO)NH, yields {sup 1}H-detected inter-residue correlations, in which we record the chemical shifts of the CA spins in the first indirect dimension while during the scalar-transfer delays the coherences are present only on the longer-lived CO spins. The second experiment, (H)(CA)CB(CA)NH, correlates the side-chain CB chemical shifts with the NH of the same residue. These high sensitivity experiments are demonstrated on both fully-protonated and 100 %-H{sup N} back-protonated perdeuterated microcrystalline samples of Acinetobacter phage 205 (AP205) capsids at 60 kHz MAS.

  9. A general assignment method for oriented sample (OS) solid-state NMR of proteins based on the correlation of resonances through heteronuclear dipolar couplings in samples aligned parallel and perpendicular to the magnetic field.

    Science.gov (United States)

    Lu, George J; Son, Woo Sung; Opella, Stanley J

    2011-04-01

    A general method for assigning oriented sample (OS) solid-state NMR spectra of proteins is demonstrated. In principle, this method requires only a single sample of a uniformly ¹⁵N-labeled membrane protein in magnetically aligned bilayers, and a previously assigned isotropic chemical shift spectrum obtained either from solution NMR on micelle or isotropic bicelle samples or from magic angle spinning (MAS) solid-state NMR on unoriented proteoliposomes. The sequential isotropic resonance assignments are transferred to the OS solid-state NMR spectra of aligned samples by correlating signals from the same residue observed in protein-containing bilayers aligned with their normals parallel and perpendicular to the magnetic field. The underlying principle is that the resonances from the same residue have heteronuclear dipolar couplings that differ by exactly a factor of two between parallel and perpendicular alignments. The method is demonstrated on the membrane-bound form of Pf1 coat protein in phospholipid bilayers, whose assignments have been previously made using an earlier generation of methods that relied on the preparation of many selectively labeled (by residue type) samples. The new method provides the correct resonance assignments using only a single uniformly ¹⁵N-labeled sample, two solid-state NMR spectra, and a previously assigned isotropic spectrum. Significantly, this approach is equally applicable to residues in alpha helices, beta sheets, loops, and any other elements of tertiary structure. Moreover, the strategy bridges between OS solid-state NMR of aligned samples and solution NMR or MAS solid-state NMR of unoriented samples. In combination with the development of complementary experimental methods, it provides a step towards unifying these apparently different NMR approaches. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Structural, (197)Au Mössbauer and solid state (31)P CP/MAS NMR studies on bis (cis-bis(diphenylphosphino)ethylene) gold(I) complexes [Au(dppey)(2)]X for X = PF(6), I.

    Science.gov (United States)

    Healy, Peter C; Loughrey, Bradley T; Bowmaker, Graham A; Hanna, John V

    2008-07-28

    (197)Au Mössbauer spectra for the d(10) gold(i) phosphine complexes, [Au(dppey)(2)]X (X = PF(6), I; dppey = (cis-bis(diphenylphosphino)ethylene), and the single crystal X-ray structure and solid state (31)P CPMAS NMR spectrum of [Au(dppey)(2)]I are reported here. In [Au(dppey)(2)]I the AuP(4) coordination geometry is distorted from the approximately D(2) symmetry observed for the PF(6)(-) complex with Au-P bond lengths 2.380(2)-2.426(2) A and inter-ligand P-Au-P angles 110.63(5)-137.71(8) degrees . Quadrupole splitting parameters derived from the Mössbauer spectra are consistent with the increased distortion of the AuP(4) coordination sphere with values of 1.22 and 1.46 mm s(-1) for the PF(6)(-) and I(-) complexes respectively. In the solid state (31)P CP MAS NMR spectrum of [Au(dppey)(2)]I, signals for each of the four crystallographically independent phosphorus nuclei are observed, with the magnitude of the (197)Au quadrupole coupling being sufficiently large to produce a collapse of (1)J(Au-P) splitting from quartets to doublets. The results highlight the important role played by the counter anion in the determination of the structural and spectroscopic properties of these sterically crowded d(10) complexes.

  11. Surface characteristics of the iron-oxyhydroxide layer formed during brick coatings by ESEM/EDS, {sup 23}Na and {sup 1}H MAS NMR, and ToF-SIMS

    Energy Technology Data Exchange (ETDEWEB)

    Allahdin, O. [Chaire Unesco « Sur la gestion de l' eau », Laboratoire Hydrosciences Lavoisier, Université de Bangui, Faculté des Sciences, B.P. 908 (Central African Republic); Wartel, M. [Université Lille1, Laboratoire LASIR (UMR CNRS 8516), Equipe Physico-chimie de l' Environnement, Bât. C8, 2" è" m" e étage, 59655 Villeneuve d' Ascq cedex (France); Mabingui, J. [Chaire Unesco « Sur la gestion de l' eau », Laboratoire Hydrosciences Lavoisier, Université de Bangui, Faculté des Sciences, B.P. 908 (Central African Republic); Revel, B. [Université Lille1, Service RMN, Bât. C4, 59655 Villeneuve d' Ascq cedex (France); Nuns, N. [Université Lille1, Institut Chevreul, 59655 Villeneuve d' Ascq cedex (France); Boughriet, A., E-mail: abdel.boughriet@univ-lille1.fr [Université Lille1, Laboratoire LASIR (UMR CNRS 8516), Equipe Physico-chimie de l' Environnement, Bât. C8, 2" è" m" e étage, 59655 Villeneuve d' Ascq cedex (France)

    2015-09-01

    Brick made locally by craftsmen in Bangui (Central African Republic) was modified first by HCl activation and second by iron-oxyhydroxide impregnation through the precipitation of ferric ions by NaOH at various fixed pH values (ranging from 3 to 13). The elemental analyses of synthesized compounds were performed using ICP-AES, and their surface chemistry/properties were investigated by environmental scanning electron microscopy (ESEM/EDS), {sup 1}H and {sup 23}Na MAS NMR spectroscopy, and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The evidence of different {sup 23}Na chemical environments and the coexistence of Si and Al bound to ferrihydrite were made. The surface properties of this material which was found to be dependent upon synthesis pH, contributed to enhance metal uptake from water. - Highlights: • HCl-activated brick was coated at different Fe(III)-precipitation pH. • Surface properties were determined by ESEM, NMR and ToF-SIMS. • Al- and Si-bearing ferrihydrite and different Na environments were detected. • The pH used for modified-brick synthesis influenced metal uptake from water.

  12. A generalized theoretical framework for the description of spin decoupling in solid-state MAS NMR: Offset effect on decoupling performance

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Kong Ooi; Meier, Beat H., E-mail: beme@ethz.ch, E-mail: maer@ethz.ch; Ernst, Matthias, E-mail: beme@ethz.ch, E-mail: maer@ethz.ch [Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich (Switzerland); Agarwal, Vipin [Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich (Switzerland); TIFR Centre for Interdisciplinary Sciences, 21 Brundavan Colony, Narsinghi, Hyderabad 500 075 (India)

    2016-09-07

    We present a generalized theoretical framework that allows the approximate but rapid analysis of residual couplings of arbitrary decoupling sequences in solid-state NMR under magic-angle spinning conditions. It is a generalization of the tri-modal Floquet analysis of TPPM decoupling [Scholz et al., J. Chem. Phys. 130, 114510 (2009)] where three characteristic frequencies are used to describe the pulse sequence. Such an approach can be used to describe arbitrary periodic decoupling sequences that differ only in the magnitude of the Fourier coefficients of the interaction-frame transformation. It allows a ∼100 times faster calculation of second-order residual couplings as a function of pulse sequence parameters than full spin-dynamics simulations. By comparing the theoretical calculations with full numerical simulations, we show the potential of the new approach to examine the performance of decoupling sequences. We exemplify the usefulness of this framework by analyzing the performance of commonly used high-power decoupling sequences and low-power decoupling sequences such as amplitude-modulated XiX (AM-XiX) and its super-cycled variant SC-AM-XiX. In addition, the effect of chemical-shift offset is examined for both high- and low-power decoupling sequences. The results show that the cross-terms between the dipolar couplings are the main contributions to the line broadening when offset is present. We also show that the SC-AM-XIX shows a better offset compensation.

  13. A generalized theoretical framework for the description of spin decoupling in solid-state MAS NMR: Offset effect on decoupling performance.

    Science.gov (United States)

    Tan, Kong Ooi; Agarwal, Vipin; Meier, Beat H; Ernst, Matthias

    2016-09-07

    We present a generalized theoretical framework that allows the approximate but rapid analysis of residual couplings of arbitrary decoupling sequences in solid-state NMR under magic-angle spinning conditions. It is a generalization of the tri-modal Floquet analysis of TPPM decoupling [Scholz et al., J. Chem. Phys. 130, 114510 (2009)] where three characteristic frequencies are used to describe the pulse sequence. Such an approach can be used to describe arbitrary periodic decoupling sequences that differ only in the magnitude of the Fourier coefficients of the interaction-frame transformation. It allows a ∼100 times faster calculation of second-order residual couplings as a function of pulse sequence parameters than full spin-dynamics simulations. By comparing the theoretical calculations with full numerical simulations, we show the potential of the new approach to examine the performance of decoupling sequences. We exemplify the usefulness of this framework by analyzing the performance of commonly used high-power decoupling sequences and low-power decoupling sequences such as amplitude-modulated XiX (AM-XiX) and its super-cycled variant SC-AM-XiX. In addition, the effect of chemical-shift offset is examined for both high- and low-power decoupling sequences. The results show that the cross-terms between the dipolar couplings are the main contributions to the line broadening when offset is present. We also show that the SC-AM-XIX shows a better offset compensation.

  14. Nuclear magnetic resonance (NMR) imaging in the diagnosis of liver disease. Differential diagnosis of hepatic tumors and correlation between NMR imaging and histological findings

    Energy Technology Data Exchange (ETDEWEB)

    Ebara, Masaaki; Oto, Masao; Sugiura, Nobuyuki; Kimura, Kunio; Okuda, Kunio; Hirooka, Noboru; Ikehira, Hiroo; Fukuda, Nobuo; Tateno, Yukio

    1984-06-01

    Characteristics of nuclear magnetic resonance (NMR) images for various liver diseases were examined using a 0.1 T resistive NMR imaging unit on 26 patients with liver disease and 10 normal volunteers. Hepatic tumors, including small hepatocellular carcinoma 1.5 cm in diameter, were detected on NMR imaging. Ring sign characteristic of nodular type hepatocellular carcinoma was shown on NMR-CT in 60 % of patients. T/sub 1/ values allowed differential diagnosis of hepatic tumors. There was close correlation between NMR images and histopathological findings. The T/sub 1/ in the liver and spleen was more prolonged in patients with liver cirrhosis than in normal volunteers, with significant differences. (Namekawa, K.).

  15. Analysis of mercerization process based on the intensity change of deconvoluted resonances of {sup 13}C CP/MAS NMR: Cellulose mercerized under cooling and non-cooling conditions

    Energy Technology Data Exchange (ETDEWEB)

    Miura, Kento [Mitsubishi Rayon Co., Ltd. Otake Research Laboratories (Japan); Nakano, Takato, E-mail: tnakano@kais.kyoto-u.ac.jp [Laboratory of Biomaterials Design, Division of Forest and Biomaterials Science, Graduate School of Agriculture, Kyoto University (Japan)

    2015-08-01

    The area intensity change of C1, C4, and C6 in spectrum obtained by {sup 13}C CP/MAS NMR and the mutual relationship between their changes were examined for cellulose samples treated with various concentrations of aqueous NaOH solutions under non-cooling and cooling conditions. The area intensity of C1-up and C6-down changed cooperatively with that of C4-down which corresponds to the crystallinity of samples: “-up” and “-down” are the up- and down- field component in a splitting peak of NMR spectrum, respectively. The intensity change of C1-up starts to decrease with decreasing in that of C4-down after that of C6-down is almost complete. These changes were more clearly observed for samples treated under cooling condition. It can be suggested that their characteristic change relates closely to the change in conformation of cellulose chains by induced decrystallization and the subsequent crystallization of cellulose II, and presumed that their changes at microscopic level relate to the macroscopic morphological changes such as contraction along the length of cellulose chains and recovery along the length. - Highlight: • Samples were mercerized at various NaOH concentrations under non-cooling and cooling. • The intensity change of C1 starts immediately after that of C6 is complete. • The creation of cell-II starts when decrystallization proceeds to a certain state. • This change relates closely to the change in conformation of cellulose chains. • The above change is more clearly found for samples treated under cooling.

  16. Identifying secondary structures in proteins using NMR chemical shift 3D correlation maps

    Science.gov (United States)

    Kumari, Amrita; Dorai, Kavita

    2013-06-01

    NMR chemical shifts are accurate indicators of molecular environment and have been extensively used as aids in protein structure determination. This work focuses on creating empirical 3D correlation maps of backbone chemical shift nuclei for use as identifiers of secondary structure elements in proteins. A correlated database of backbone nuclei chemical shifts was constructed from experimental structural data gathered from entries in the Protein Data Bank (PDB) as well as isotropic chemical shift values from the RefDB database. Rigorous statistical analysis of the maps led to the conclusion that specific correlations between triplets of backbone chemical shifts are best able to differentiate between different secondary structures such as α-helices, β-strands and turns. The method is compared with similar techniques that use NMR chemical shift information as aids in biomolecular structure determination and performs well in tests done on experimental data determined for different types of proteins, including large multi-domain proteins and membrane proteins.

  17. Simultaneous acquisition for T2 -T2 Exchange and T1 -T2 correlation NMR experiments

    Science.gov (United States)

    Montrazi, Elton T.; Lucas-Oliveira, Everton; Araujo-Ferreira, Arthur G.; Barsi-Andreeta, Mariane; Bonagamba, Tito J.

    2018-04-01

    The NMR measurements of longitudinal and transverse relaxation times and its multidimensional correlations provide useful information about molecular dynamics. However, these experiments are very time-consuming, and many researchers proposed faster experiments to reduce this issue. This paper presents a new way to simultaneously perform T2 -T2 Exchange and T1 -T2 correlation experiments by taking the advantage of the storage time and the two steps phase cycling used for running the relaxation exchange experiment. The data corresponding to each step is either summed or subtracted to produce the T2 -T2 and T1 -T2 data, enhancing the information obtained while maintaining the experiment duration. Comparing the results from this technique with traditional NMR experiments it was possible to validate the method.

  18. Quantifying NMR relaxation correlation and exchange in articular cartilage with time domain analysis

    Science.gov (United States)

    Mailhiot, Sarah E.; Zong, Fangrong; Maneval, James E.; June, Ronald K.; Galvosas, Petrik; Seymour, Joseph D.

    2018-02-01

    Measured nuclear magnetic resonance (NMR) transverse relaxation data in articular cartilage has been shown to be multi-exponential and correlated to the health of the tissue. The observed relaxation rates are dependent on experimental parameters such as solvent, data acquisition methods, data analysis methods, and alignment to the magnetic field. In this study, we show that diffusive exchange occurs in porcine articular cartilage and impacts the observed relaxation rates in T1-T2 correlation experiments. By using time domain analysis of T2-T2 exchange spectroscopy, the diffusive exchange time can be quantified by measurements that use a single mixing time. Measured characteristic times for exchange are commensurate with T1 in this material and so impacts the observed T1 behavior. The approach used here allows for reliable quantification of NMR relaxation behavior in cartilage in the presence of diffusive fluid exchange between two environments.

  19. Theoretical investigations of quantum correlations in NMR multiple-pulse spin-locking experiments

    Science.gov (United States)

    Gerasev, S. A.; Fedorova, A. V.; Fel'dman, E. B.; Kuznetsova, E. I.

    2018-04-01

    Quantum correlations are investigated theoretically in a two-spin system with the dipole-dipole interactions in the NMR multiple-pulse spin-locking experiments. We consider two schemes of the multiple-pulse spin-locking. The first scheme consists of π /2-pulses only and the delays between the pulses can differ. The second scheme contains φ-pulses (0Quantum discord is obtained for the first scheme of the multiple-pulse spin-locking experiment at different temperatures.

  20. (13)C-(15)N correlation via unsymmetrical indirect covariance NMR: application to vinblastine.

    Science.gov (United States)

    Martin, Gary E; Hilton, Bruce D; Blinov, Kirill A; Williams, Antony J

    2007-12-01

    Unsymmetrical indirect covariance processing methods allow the derivation of hyphenated 2D NMR data from the component 2D spectra, potentially circumventing the acquisition of the much lower sensitivity hyphenated 2D NMR experimental data. Calculation of HSQC-COSY and HSQC-NOESY spectra from GHSQC, COSY, and NOESY spectra, respectively, has been reported. The use of unsymmetrical indirect covariance processing has also been applied to the combination of (1)H- (13)C GHSQC and (1)H- (15)N long-range correlation data (GHMBC, IMPEACH, or CIGAR-HMBC). The application of unsymmetrical indirect covariance processing to spectra of vinblastine is now reported, specifically the algorithmic extraction of (13)C- (15)N correlations via the unsymmetrical indirect covariance processing of the combination of (1)H- (13)C GHSQC and long-range (1)H- (15)N GHMBC to produce the equivalent of a (13)C- (15)N HSQC-HMBC correlation spectrum. The elimination of artifact responses with aromatic solvent-induced shifts (ASIS) is shown in addition to a method of forecasting potential artifact responses through the indirect covariance processing of the GHSQC spectrum used in the unsymmetrical indirect covariance processing.

  1. Spatially resolved D-T(2) correlation NMR of porous media.

    Science.gov (United States)

    Zhang, Yan; Blümich, Bernhard

    2014-05-01

    Within the past decade, 2D Laplace nuclear magnetic resonance (NMR) has been developed to analyze pore geometry and diffusion of fluids in porous media on the micrometer scale. Many objects like rocks and concrete are heterogeneous on the macroscopic scale, and an integral analysis of microscopic properties provides volume-averaged information. Magnetic resonance imaging (MRI) resolves this spatial average on the contrast scale set by the particular MRI technique. Desirable contrast parameters for studies of fluid transport in porous media derive from the pore-size distribution and the pore connectivity. These microscopic parameters are accessed by 1D and 2D Laplace NMR techniques. It is therefore desirable to combine MRI and 2D Laplace NMR to image functional information on fluid transport in porous media. Because 2D Laplace resolved MRI demands excessive measuring time, this study investigates the possibility to restrict the 2D Laplace analysis to the sum signals from low-resolution pixels, which correspond to pixels of similar amplitude in high-resolution images. In this exploratory study spatially resolved D-T2 correlation maps from glass beads and mortar are analyzed. Regions of similar contrast are first identified in high-resolution images to locate corresponding pixels in low-resolution images generated with D-T2 resolved MRI for subsequent pixel summation to improve the signal-to-noise ratio of contrast-specific D-T2 maps. This method is expected to contribute valuable information on correlated sample heterogeneity from the macroscopic and the microscopic scales in various types of porous materials including building materials and rock. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. NMR spectroscopy, Hammett correlations and biological activity of some Schiff bases derived from piperonal

    International Nuclear Information System (INIS)

    Echevarria, Aurea; Giesbrecht, Astrea

    1999-01-01

    A series of eleven Schiff Bases have been synthesized. They were obtained by condensation of piperonal (3,4-methylenedioxybenzaldehyde) with the corresponding aromatic primary amines. Their 1 H and 13 C-NMR spectra have been obtained and the Hammett correlations including chemical shifts and the substituent constants (σ p , σR e σI) were studied. Linear and bilinear significant correlations were observed for iminic carbon (C-α) and C-1 ' , showing a more significant resonance effect on chemical shifts. The chemical shifts for C-4 ' were highly affected by substituent effects, especially for halogens in the expected direction. Their biological activity against microorganisms has also been measured and significant activity was showed against Epidermophyton floccosum. The biological activity did not give a reasonable relationship with electronic effects. (author)

  3. Parent heparin and daughter LMW heparin correlation analysis using LC-MS and NMR

    International Nuclear Information System (INIS)

    Liu, Xinyue; St Ange, Kalib; Wang, Xiaohua; Lin, Lei; Zhang, Fuming

    2017-01-01

    Heparin is a structurally complex, polysaccharide anticoagulant derived from livestock, primarily porcine intestinal tissues. Low molecular weight (LMW) heparins are derived through the controlled partial depolymerization of heparin. Increased manufacturing and regulatory concerns have provided the motivation for the development of more sophisticated analytical methods for determining both their structure and pedigree. A strategy, for the comprehensive comparison of parent heparins and their LMW heparin daughters, is described that relies on the analysis of monosaccharide composition, disaccharide composition, and oligosaccharide composition. Liquid chromatography-mass spectrometry is rapid, robust, and amenable to automated processing and interpretation of both top-down and bottom-up analyses. Nuclear magnetic resonance spectroscopy provides complementary top-down information on the chirality of the uronic acid residues and glucosamine substitution. Principal component analysis (PCA) was applied to the normalized abundance of oligosaccharides, calculated in the bottom-up analysis, to show parent and daughter correlation in oligosaccharide composition. Using these approaches, six pairs of parent heparins and their daughter generic enoxaparins from two different manufacturers were comprehensively analyzed. Enoxaparin is the most widely used LMW heparin and is prepared through controlled chemical β-eliminative cleavage of porcine intestinal heparin. Lovenox"®, the innovator version of enoxaparin marketed in the US, was analyzed as a reference for the daughter LMW heparins. The results, show similarities between LMW heparins from two different manufacturers with Lovenox"®, excellent lot-to-lot consistency of products from each manufacturer, and detects a correlation between each parent heparin and daughter LMW heparin. - Highlights: • Low molecular weight heparins prepared from different heparin parents were analyzed. • An integrated analytical approach relied

  4. Parent heparin and daughter LMW heparin correlation analysis using LC-MS and NMR

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xinyue, E-mail: liux22@rpi.edu [National Glycoengineering Research Center, Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, State Key Laboratory of Microbial Technology, Shandong University, Jinan, Shandong, 250100 (China); Department of Chemistry and Chemical Biology, Department of Chemical and Biological Engineering, Department of Biology, Department of Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, 12180 (United States); St Ange, Kalib, E-mail: stangk2@rpi.edu [Department of Chemistry and Chemical Biology, Department of Chemical and Biological Engineering, Department of Biology, Department of Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, 12180 (United States); Wang, Xiaohua, E-mail: wangx35@rpi.edu [Department of Chemistry and Chemical Biology, Department of Chemical and Biological Engineering, Department of Biology, Department of Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, 12180 (United States); School of Computer and Information, Hefei University of Technology, Hefei (China); Lin, Lei, E-mail: Linl5@rpi.edu [Department of Chemistry and Chemical Biology, Department of Chemical and Biological Engineering, Department of Biology, Department of Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, 12180 (United States); Zhang, Fuming, E-mail: zhangf2@rpi.edu [Department of Chemistry and Chemical Biology, Department of Chemical and Biological Engineering, Department of Biology, Department of Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, 12180 (United States); and others

    2017-04-08

    Heparin is a structurally complex, polysaccharide anticoagulant derived from livestock, primarily porcine intestinal tissues. Low molecular weight (LMW) heparins are derived through the controlled partial depolymerization of heparin. Increased manufacturing and regulatory concerns have provided the motivation for the development of more sophisticated analytical methods for determining both their structure and pedigree. A strategy, for the comprehensive comparison of parent heparins and their LMW heparin daughters, is described that relies on the analysis of monosaccharide composition, disaccharide composition, and oligosaccharide composition. Liquid chromatography-mass spectrometry is rapid, robust, and amenable to automated processing and interpretation of both top-down and bottom-up analyses. Nuclear magnetic resonance spectroscopy provides complementary top-down information on the chirality of the uronic acid residues and glucosamine substitution. Principal component analysis (PCA) was applied to the normalized abundance of oligosaccharides, calculated in the bottom-up analysis, to show parent and daughter correlation in oligosaccharide composition. Using these approaches, six pairs of parent heparins and their daughter generic enoxaparins from two different manufacturers were comprehensively analyzed. Enoxaparin is the most widely used LMW heparin and is prepared through controlled chemical β-eliminative cleavage of porcine intestinal heparin. Lovenox{sup ®}, the innovator version of enoxaparin marketed in the US, was analyzed as a reference for the daughter LMW heparins. The results, show similarities between LMW heparins from two different manufacturers with Lovenox{sup ®}, excellent lot-to-lot consistency of products from each manufacturer, and detects a correlation between each parent heparin and daughter LMW heparin. - Highlights: • Low molecular weight heparins prepared from different heparin parents were analyzed. • An integrated analytical

  5. NMR-based metabonomics and correlation analysis reveal potential biomarkers associated with chronic atrophic gastritis.

    Science.gov (United States)

    Cui, Jiajia; Liu, Yuetao; Hu, Yinghuan; Tong, Jiayu; Li, Aiping; Qu, Tingli; Qin, Xuemei; Du, Guanhua

    2017-01-05

    Chronic atrophic gastritis (CAG) is one of the most important pre-cancerous states with a high prevalence. Exploring of the underlying mechanism and potential biomarkers is of significant importance for CAG. In the present work, 1 H NMR-based metabonomics with correlative analysis was performed to analyze the metabolic features of CAG. 19 plasma metabolites and 18 urine metabolites were enrolled to construct the circulatory and excretory metabolome of CAG, which was in response to alterations of energy metabolism, inflammation, immune dysfunction, as well as oxidative stress. 7 plasma biomarkers and 7 urine biomarkers were screened to elucidate the pathogenesis of CAG based on the further correlation analysis with biochemical indexes. Finally, 3 plasma biomarkers (arginine, succinate and 3-hydroxybutyrate) and 2 urine biomarkers (α-ketoglutarate and valine) highlighted the potential to indicate risks of CAG in virtue of correlation with pepsin activity and ROC analysis. Here, our results paved a way for elucidating the underlying mechanisms in the development of CAG, and provided new avenues for the diagnosis of CAG and presented potential drug targets for treatment of CAG. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Correlations between the 1H NMR chemical shieldings and the pKa values of organic acids and amines.

    Science.gov (United States)

    Lu, Juanfeng; Lu, Tingting; Zhao, Xinyun; Chen, Xi; Zhan, Chang-Guo

    2018-06-01

    The acid dissociation constants and 1 H NMR chemical shieldings of organic compounds are important properties that have attracted much research interest. However, few studies have explored the relationship between these two properties. In this work, we theoretically studied the NMR chemical shifts of a series of carboxylic acids and amines in the gas phase and in aqueous solution. It was found that the negative logarithms of the experimental acid dissociation constants (i.e., the pK a values) of the organic acids and amines in aqueous solution correlate almost linearly with the corresponding calculated NMR chemical shieldings. Key factors that affect the theoretically predicted pK a values are discussed in this paper. The present work provides a new way to predict the pK a values of organic/biochemical compounds. Graphical abstract The chemical shielding values of organic acids and amines correlate near linearly with their corresponding pK a values.

  7. FoodPro: A Web-Based Tool for Evaluating Covariance and Correlation NMR Spectra Associated with Food Processes

    Directory of Open Access Journals (Sweden)

    Eisuke Chikayama

    2016-10-01

    Full Text Available Foods from agriculture and fishery products are processed using various technologies. Molecular mixture analysis during food processing has the potential to help us understand the molecular mechanisms involved, thus enabling better cooking of the analyzed foods. To date, there has been no web-based tool focusing on accumulating Nuclear Magnetic Resonance (NMR spectra from various types of food processing. Therefore, we have developed a novel web-based tool, FoodPro, that includes a food NMR spectrum database and computes covariance and correlation spectra to tasting and hardness. As a result, FoodPro has accumulated 236 aqueous (extracted in D2O and 131 hydrophobic (extracted in CDCl3 experimental bench-top 60-MHz NMR spectra, 1753 tastings scored by volunteers, and 139 hardness measurements recorded by a penetrometer, all placed into a core database. The database content was roughly classified into fish and vegetable groups from the viewpoint of different spectrum patterns. FoodPro can query a user food NMR spectrum, search similar NMR spectra with a specified similarity threshold, and then compute estimated tasting and hardness, covariance, and correlation spectra to tasting and hardness. Querying fish spectra exemplified specific covariance spectra to tasting and hardness, giving positive covariance for tasting at 1.31 ppm for lactate and 3.47 ppm for glucose and a positive covariance for hardness at 3.26 ppm for trimethylamine N-oxide.

  8. FoodPro: A Web-Based Tool for Evaluating Covariance and Correlation NMR Spectra Associated with Food Processes.

    Science.gov (United States)

    Chikayama, Eisuke; Yamashina, Ryo; Komatsu, Keiko; Tsuboi, Yuuri; Sakata, Kenji; Kikuchi, Jun; Sekiyama, Yasuyo

    2016-10-19

    Foods from agriculture and fishery products are processed using various technologies. Molecular mixture analysis during food processing has the potential to help us understand the molecular mechanisms involved, thus enabling better cooking of the analyzed foods. To date, there has been no web-based tool focusing on accumulating Nuclear Magnetic Resonance (NMR) spectra from various types of food processing. Therefore, we have developed a novel web-based tool, FoodPro, that includes a food NMR spectrum database and computes covariance and correlation spectra to tasting and hardness. As a result, FoodPro has accumulated 236 aqueous (extracted in D₂O) and 131 hydrophobic (extracted in CDCl₃) experimental bench-top 60-MHz NMR spectra, 1753 tastings scored by volunteers, and 139 hardness measurements recorded by a penetrometer, all placed into a core database. The database content was roughly classified into fish and vegetable groups from the viewpoint of different spectrum patterns. FoodPro can query a user food NMR spectrum, search similar NMR spectra with a specified similarity threshold, and then compute estimated tasting and hardness, covariance, and correlation spectra to tasting and hardness. Querying fish spectra exemplified specific covariance spectra to tasting and hardness, giving positive covariance for tasting at 1.31 ppm for lactate and 3.47 ppm for glucose and a positive covariance for hardness at 3.26 ppm for trimethylamine N -oxide.

  9. Alpha shift correlation (ASC) method. Sensitivity of B-11 NMR shifts to halogen substitution in the ten-vertex nido and arachno series of boron clusters. Linear behavior of NMR effects

    Czech Academy of Sciences Publication Activity Database

    Štíbr, Bohumil

    2018-01-01

    Roč. 471, FEB (2018), s. 615-619 ISSN 0020-1693 R&D Projects: GA ČR(CZ) GA16-01618S Institutional support: RVO:61388980 Keywords : Boranes * Dicarbaboranes * NMR shifts- B NMR correlation 11 * Sensitivity factors * Substitution effects Subject RIV: CA - Inorganic Chemistry OBOR OECD: Inorganic and nuclear chemistry Impact factor: 2.002, year: 2016

  10. Measuring diffusion-relaxation correlation maps using non-uniform field gradients of single-sided NMR devices.

    Science.gov (United States)

    Nogueira d'Eurydice, Marcel; Galvosas, Petrik

    2014-11-01

    Single-sided NMR systems are becoming a relevant tool in industry and laboratory environments due to their low cost, low maintenance and capacity to evaluate quantity and quality of hydrogen based materials. The performance of such devices has improved significantly over the last decade, providing increased field homogeneity, field strength and even controlled static field gradients. For a class of these devices, the configuration of the permanent magnets provides a linear variation of the magnetic field and can be used in diffusion measurements. However, magnet design depends directly on its application and, according to the purpose, the field homogeneity may significantly be compromised. This may prevent the determination of diffusion properties of fluids based on the natural inhomogeneity of the field using known techniques. This work introduces a new approach that extends the applicability of diffusion-editing CPMG experiments to NMR devices with highly inhomogeneous magnetic fields, which do not vary linearly in space. Herein, we propose a method to determine a custom diffusion kernel based on the gradient distribution, which can be seen as a signature of each NMR device. This new diffusion kernel is then utilised in the 2D inverse Laplace transform (2D ILT) in order to determine diffusion-relaxation correlation maps of homogeneous multi-phasic fluids. The experiments were performed using NMR MObile Lateral Explore (MOLE), which is a single-sided NMR device designed to maximise the volume at the sweet spot with enhanced depth penetration. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Carbonaceous species (coke) characterization in zeolites by solid state {sup 13} C NMR; Caracterizacao de especies carbonaceas (coque) em zeolitos por RMN de {sup 13} C estado solido (CP/MAS)

    Energy Technology Data Exchange (ETDEWEB)

    Mota, Claudio J.A.; Menezes, Sonia C [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

    1992-12-31

    This work applies solid state {sup 13} C NMR for characterization of carbonaceous species (coke) deposited on zeolites after contact with n-hexane at 370 deg C. The results have shown two types of carbon: saturated (sp{sup 3}) and unsaturated (sp{sup 2}) 4 refs., 4 tabs.

  12. The NMR probe of high-Tc materials and correlated electron systems. 2. ed.

    International Nuclear Information System (INIS)

    Walstedt, Russell E.

    2018-01-01

    This new edition updates readers in three areas of NMR studies, namely, recent developments in high-T c materials, heavy fermion systems and actinide oxides are presented. The NMR probe has yielded a vast array of data for solid state materials, corresponding to different compounds, ionic sites, and nuclear species, as well as to a wide variety of experimental conditions. The last two parts of the book are completely new in this edition, while the first part has seen major updates. This edition features the latest developments for high-T c materials, especially the advances in the area of pseudogap studies are reviewed. An in depth overview of heavy fermion systems is presented in the second part, notably Kondo lattices, quantum critical points and unconventional superconductivity are areas of intense research recently and are covered extensively. Finally, valuable information from NMR studies with actinide oxides will be provided. Ongoing analysis and discussion of NMR data have resulted in a wealth of important insights into the physics of these exotic systems. The aims of this monograph are manifold. First, it reviews NMR methodology as it has been applied to the different studies. This is addressed to NMR practitioners and to physics laypersons alike. Next, it presents a review of NMR measurements and the wide variety of phenomena which they represent. The third phase is to recount the theoretical model calculations and other proposals which have been put forward to account for these data.

  13. The NMR probe of high-T{sub c} materials and correlated electron systems. 2. ed.

    Energy Technology Data Exchange (ETDEWEB)

    Walstedt, Russell E. [Michigan Univ., Ann Arbor, MI (United States). Dept. of Physics

    2018-03-01

    This new edition updates readers in three areas of NMR studies, namely, recent developments in high-T{sub c} materials, heavy fermion systems and actinide oxides are presented. The NMR probe has yielded a vast array of data for solid state materials, corresponding to different compounds, ionic sites, and nuclear species, as well as to a wide variety of experimental conditions. The last two parts of the book are completely new in this edition, while the first part has seen major updates. This edition features the latest developments for high-T{sub c} materials, especially the advances in the area of pseudogap studies are reviewed. An in depth overview of heavy fermion systems is presented in the second part, notably Kondo lattices, quantum critical points and unconventional superconductivity are areas of intense research recently and are covered extensively. Finally, valuable information from NMR studies with actinide oxides will be provided. Ongoing analysis and discussion of NMR data have resulted in a wealth of important insights into the physics of these exotic systems. The aims of this monograph are manifold. First, it reviews NMR methodology as it has been applied to the different studies. This is addressed to NMR practitioners and to physics laypersons alike. Next, it presents a review of NMR measurements and the wide variety of phenomena which they represent. The third phase is to recount the theoretical model calculations and other proposals which have been put forward to account for these data.

  14. A combined NMR and XRD study of AFI and AEL type molecular sieves

    NARCIS (Netherlands)

    Peeters, M.P.J.; Ven, van de L.J.M.; Haan, de J.W.; Hooff, van J.H.C.

    1993-01-01

    Calcined dehydrated AlPO4-5 was studied by x-ray powder diffraction, 31P MAS, and 27Al double-resonance (DOR) NMR. Three crystallog. different sites can be distinguished in the structure of dehydrated AlPO4-5 in the ratio 1:1:1. The obsd. splitting of the NMR spectra is correlated to the line width

  15. Two-dimensional NMR spectroscopy: correlated, homonuclear-correlated, and nuclear Overhauser spectroscopy. January 1975-December 1988 (Citations from the INSPEC: Information Services for the Physics and Engineering Communities data base). Report for January 1975-December 1988

    International Nuclear Information System (INIS)

    1988-12-01

    This bibliography contains citations concerning the enhanced analytical techniques of two-dimensional nuclear magnetic resonance (2-D NMR). Applications to specific molecules, biomolecules, and compounds as well as comparisons of three 2-D NMR techniques: correlated spectroscopy (COSY), nuclear Overhauser (NOSEY), and homonuclear-correlated spectroscopy (HOMCOR). (Contains 190 citations fully indexed and including a title list.)

  16. The NMR probe of high-Tc materials and correlated electron systems

    CERN Document Server

    Walstedt, Russell E

    2018-01-01

    This new edition updates readers in three areas of NMR studies, namely, recent developments in high-Tc materials, heavy fermion systems and actinide oxides are presented.  The NMR probe has yielded a vast array of data for solid state materials, corresponding to different compounds, ionic sites, and nuclear species, as well as to a wide variety of experimental conditions. The last two parts of the book are completely new in this edition, while the first part has seen major updates. This edition features the latest developments for high-Tc materials, especially the advances in the area of pseudogap studies are reviewed.  An in depth overview of heavy fermion systems is presented in the second part,  notably Kondo lattices, quantum critical points and unconventional superconductivity are areas of intense research recently and are covered extensively. Finally, valuable information from NMR studies with actinide oxides will be provided. Ongoing analysis and discussion of NMR data have resulted in a wealth o...

  17. Perturbed Angular Correlation (PAC)/NMR spectroscopic properties and dynamics of compounds containing metal ions

    DEFF Research Database (Denmark)

    Arcisauskaité, Vaida

    have been used to elucidate Hg coordination in proteins. Computational chemistry calculations have a potential to contribute to the interpretation of this spectroscopic data, as calculated diagonalised electric field gradient (EFG) tensor components (jVzzj jVyyj jVxxj) and NMR shielding constants...... steps towards understanding how Zn(II) reaches its target position in biological systems in vivo and in vitro experiments in aqueous solution, is the detailed investigation of water exchange reactions for Zn(II)(aq). A very advanced (albeit not complete) picture of structure and dynamics of solvated Zn...

  18. Preliminary observations on the correlation of proliferative phenomena with in vivo /sup 31/P NMR spectroscopy after tumor chemotherapy

    International Nuclear Information System (INIS)

    Schiffer, L.M.; Braunschweiger, P.G.; Glickson, J.D.; Evanochko, W.T.; Ng, T.C.

    1985-01-01

    In order to translate the concepts that have been developed in animal systems to human treatment programs, there is an urgent need for noninvasive techniques to study tumor cell biology. The characteristics of the ideal technique for the noninvasive monitoring of cell proliferation are truly imposing. The method should not require repeated biopsies; it should be amenable to repeated studies at frequent intervals without patient discomfort; it should monitor the proliferative response to the treatment modality; and it should not, in itself, perturb the tumor. Ideally, one would also like to be able to evaluate normal cell proliferation as well. It appears now that a new technique, /sup 31/P nuclear magnetic resonance (/sup 31/PNMR), may fulfill these rather rigid requirements. However, many studies in animal systems are necessary before it can be applied to the study of human tumors. The theory and mechanics of /sup 31/P NMR have been well described. Recently, its use as a noninvasive technique to study in vivo metabolic processes has become important. The authors presented a series of reports on the use of /sup 31/P NMR for the evaluation of tumor metabolism in animal systems under a variety of conditions. Studies of subcutaneously transplanted mouse tumors and human xenografts detected significant changes in nucleotide triphosphate (NTP), phosphocreatine, and inorganic phosphorus (Pi) as a result of tumor growth and perturbation with chemotherapeutic drugs, radiation, and hyperthermia. Their collabortive studies were designed to evaluate the changing effects of a noncurative single dose of cyclophosphamide on the /sup 31/P NMR resonances from the RIF-1 tumor, and to compare them with the proliferative changes that occur with time after drug administration. They were carried out in the hope of finding a noninvasive correlate with tumor cell proliferation

  19. Manifestations of classical physics in the quantum evolution of correlated spin states in pulsed NMR experiments.

    Science.gov (United States)

    Ligare, Martin

    2016-05-01

    Multiple-pulse NMR experiments are a powerful tool for the investigation of molecules with coupled nuclear spins. The product operator formalism provides a way to understand the quantum evolution of an ensemble of weakly coupled spins in such experiments using some of the more intuitive concepts of classical physics and semi-classical vector representations. In this paper I present a new way in which to interpret the quantum evolution of an ensemble of spins. I recast the quantum problem in terms of mixtures of pure states of two spins whose expectation values evolve identically to those of classical moments. Pictorial representations of these classically evolving states provide a way to calculate the time evolution of ensembles of weakly coupled spins without the full machinery of quantum mechanics, offering insight to anyone who understands precession of magnetic moments in magnetic fields.

  20. E/Z MAS demonstration

    International Nuclear Information System (INIS)

    Boor, M.G.; Hurford, J.M.; Landry, R.P.; Martinez, B.J.; Solem, A.M.; Whiteson, R.; Zardecki, A.

    1998-01-01

    Los Alamos National Laboratory has developed E/Z MAS, a new generation nuclear material accountability application based on the latest technology and designed for facilities required to track nuclear materials with a simple-to-use interface. E/Z MAS is based on years of experience spent developing nuclear material accounting systems. E/Z MAS uses a modern relational database with a web server and enables users on a classified local area network to interact with the database with web browsers. The E/Z MAS Demonstration poster session demonstrates the E/Z MAS functions required by an operational nuclear facility to track material as it enters and leaves a facility and to account for the material as it moves through a process. The generation of internal facility reports and external reports for the Russian Federal system will be demonstrated. Bar-code readers will be used to demonstrate the ability of EZ MAS to automate certain functions, such as physical inventories at facilities

  1. Structural Characterization of MAO and Related Aluminum Complexes. 1. Solid-State 27 Al NMR with Comparison to EFG Tensors from ab Initio Molecular Orbital Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, Pamela L.; Harwell, Chris; Mrse, Anthony A.; Emery, Earl F.; Gan, Zhedong; Caldwell, Tod; Reyes, Arneil P.; Kuhns, Philip; Hoyt, David W.; Simeral, Larry S.; Hall, Randall W.; Butler, Leslie G.

    2001-11-07

    Aminato and propanolato aluminum clusters with 3-, 4-, and 6-coordinate aluminum sites are studied with three 27Al NMR techniques optimized for large 27Al Quadrupole coupling constants: field-swept, frequency-stepped, and high-field MAS NMR. The 27Al quadrupole coupling constants and asymmetry parameters of molecular species, both experimental and derived from ab initio molecular orbital calculations, are correlated with structure.

  2. Mn55 NMR investigation of the correlation between antiferromagnetism and ferroelectricity in TbMn2O5

    Science.gov (United States)

    Baek, S.-H.; Reyes, A. P.; Hoch, M. J. R.; Moulton, W. G.; Kuhns, P. L.; Harter, A. G.; Hur, N.; Cheong, S.-W.

    2006-10-01

    The correlation between antiferromagnetism and ferroelectricity in magnetoelectric multiferroic TbMn2O5 has been investigated by zero-field Mn55 NMR. Antiferromagnetic transition near 40K is found to be first order. When an external field up to 7T is applied along the easy a axis, a dramatic change in the signal intensity is observed which is hysteretic in nature. Such effects are absent for H along the b and c axes. The observed field-induced signal enhancement is attributed to antiferromagnetic domain walls which are strongly coupled to ferroelectric domain walls. Experimental data suggest that this may be related to the field-induced ferromagnetic ordering of the Tb ion.

  3. Brain oxidative metabolism of the newborn dog: correlation between 31P NMR spectroscopy and pyridine nucleotide redox state.

    Science.gov (United States)

    Mayevsky, A; Nioka, S; Subramanian, V H; Chance, B

    1988-04-01

    The effects of both anoxia and short- and long-term hypoxia on brain oxidative metabolism were studied in newborn dogs. Oxidative metabolism was evaluated by two independent measures: in vivo continuous monitoring of mitochondrial NADH redox state and energy stores as calculated from the phosphocreatine (PCr)/Pi levels measured by 31P nuclear magnetic resonance (NMR) spectroscopy. The hemodynamic response to low oxygen supply was further evaluated by measuring the changes in the reflected light intensity at 366 nm (the excitation wavelength for NADH). The animal underwent surgery and was prepared for monitoring of the two signals (NADH and PCr/Pi). It was then placed inside a Phosphoenergetics 260-80 NMR spectrometer magnet with a 31-cm bore. Each animal (1-21 days old) was exposed to short-term anoxia or hypoxia as well as to long-term hypoxia (1-2 h). The results can be summarized as follow: (a) In the normoxic brain, the ratio between PCr and Pi was greater than 1 (1.2-1.4), while under hypoxia or asphyxia a significant decrease that was correlated to the FiO2 levels was recorded. (b) A clear correlation was found between the decrease in PCr/Pi values and the increased NADH redox state developed under decreased O2 supply to the brain. (c) Exposing the animal to moderately long-term hypoxia led to a stabilized low-energy state of the brain with a good recovery after rebreathing normal air. (d) Under long-term and severe hypoxia, the microcirculatory autoregulatory mechanism was damaged and massive vasoconstriction was optically recorded simultaneously with a significant decrease in PCr/Pi values.(ABSTRACT TRUNCATED AT 250 WORDS)

  4. Shale characteristics impact on Nuclear Magnetic Resonance (NMR fluid typing methods and correlations

    Directory of Open Access Journals (Sweden)

    Mohamed Mehana

    2016-06-01

    Full Text Available The development of shale reservoirs has brought a paradigm shift in the worldwide energy equation. This entails developing robust techniques to properly evaluate and unlock the potential of those reservoirs. The application of Nuclear Magnetic Resonance techniques in fluid typing and properties estimation is well-developed in conventional reservoirs. However, Shale reservoirs characteristics like pore size, organic matter, clay content, wettability, adsorption, and mineralogy would limit the applicability of the used interpretation methods and correlation. Some of these limitations include the inapplicability of the controlling equations that were derived assuming fast relaxation regime, the overlap of different fluids peaks and the lack of robust correlation to estimate fluid properties in shale. This study presents a state-of-the-art review of the main contributions presented on fluid typing methods and correlations in both experimental and theoretical side. The study involves Dual Tw, Dual Te, and doping agent's application, T1-T2, D-T2 and T2sec vs. T1/T2 methods. In addition, fluid properties estimation such as density, viscosity and the gas-oil ratio is discussed. This study investigates the applicability of these methods along with a study of the current fluid properties correlations and their limitations. Moreover, it recommends the appropriate method and correlation which are capable of tackling shale heterogeneity.

  5. TiO{sub 2} colloidal nanocrystals surface modification by V{sub 2}O{sub 5} species: Investigation by {sup 47,49}Ti MAS-NMR and H{sub 2}, CO and NO{sub 2} sensing properties

    Energy Technology Data Exchange (ETDEWEB)

    Epifani, Mauro, E-mail: mauro.epifani@le.imm.cnr.it [Consiglio Nazionale delle Ricerche—Istituto per la Microelettronica e Microsistemi (CNR–IMM), via Monteroni c/o Campus Universitario, I-73100 Lecce (Italy); Comini, Elisabetta [SENSOR Lab, Department of Information Engineering, Brescia University and CNR-INO, via Valotti 9, 25133 Brescia (Italy); Díaz, Raül [Electrochemical Processes Unit, IMDEA Energy Institute, Avda. Ramón de la Sagra 3, 28935 Móstoles (Spain); Force, Carmen [NMR Unit, Centro de Apoyo Tecnológico, Universidad Rey Juan Carlos, c/Tulipán, s/n, 28933 Móstoles (Spain); Siciliano, Pietro [Consiglio Nazionale delle Ricerche—Istituto per la Microelettronica e Microsistemi (CNR–IMM), via Monteroni c/o Campus Universitario, I-73100 Lecce (Italy); Faglia, Guido [SENSOR Lab, Department of Information Engineering, Brescia University and CNR-INO, via Valotti 9, 25133 Brescia (Italy)

    2015-10-01

    Highlights: • Novel sensing architecture is presented, made by V{sub 2}O{sub 5} modification of TiO{sub 2} surface. • MAS NMR techniques are a powerful tool for studying the influence of the V{sub 2}O{sub 5} layer. • The V{sub 2}O{sub 5} surface deposition enhanced the adsorption properties with respect to pure TiO{sub 2}. - Abstract: TiO{sub 2} and TiO{sub 2}–V{sub 2}O{sub 5} nanocrystals were prepared by coupling sol–gel and solvothermal methods, followed by heat-treatment at 400 °C, after which the mean nanocrystal size was about 5 nm. The materials were characterized by X-ray diffraction, transmission electron microscopy and solid state nuclear magnetic resonance spectroscopy. It was shown that while the TiO{sub 2} phase was always anatase even after heat-treatment at 500 °C, the presence of the vanadium oxide species enhanced the surface re-configuration of the Ti ions. Hence the coordination environment of surface Ti atoms was drastically changed, by formation of further bonds and imposition of a given local geometry. The final hypothesis was that in pure titania surface rearrangement occurs, leading to the new NMR signal, but this modification was favored in the TiO{sub 2}–V{sub 2}O{sub 5} sample, where the Ti surface atoms were forced into the final configurations by the bonding with V atoms through oxygen. The materials heat-treated at 400 °C were used to process chemoresistive sensors, which were tested to hydrogen, CO and NO{sub 2}, as examples of gases with peculiar sensing mechanisms. The results evidenced that the surface deposition of V{sub 2}O{sub 5} onto the anatase TiO{sub 2} nanocrystals was effective in modifying the adsorption properties of the anatase nanocrystals.

  6. Lithium ion mobility in lithium phosphidosilicates: Crystal structure, {sup 7}Li, {sup 29}Si, and {sup 31}P MAS NMR spectroscopy, and impedance spectroscopy of Li{sub 8}SiP{sub 4} and Li{sub 2}SiP{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Toffoletti, Lorenzo; Landesfeind, Johannes; Klein, Wilhelm; Gasteiger, Hubert A.; Faessler, Thomas F. [Department of Chemistry, Technische Universitaet Muenchen, Lichtenbergstrasse 4, 85747, Garching bei Muenchen (Germany); Kirchhain, Holger; Wuellen, Leo van [Department of Physics, University of Augsburg, Universitaetsstrasse 1, 86159, Augsburg (Germany)

    2016-12-05

    The need to improve electrodes and Li-ion conducting materials for rechargeable all-solid-state batteries has drawn enhanced attention to the investigation of lithium-rich compounds. The study of the ternary system Li-Si-P revealed a series of new compounds, two of which, Li{sub 8}SiP{sub 4} and Li{sub 2}SiP{sub 2}, are presented. Both phases represent members of a new family of Li ion conductors that display Li ion conductivity in the range from 1.15(7) x 10{sup -6} Scm{sup -1} at 0 C to 1.2(2) x 10{sup -4} Scm{sup -1} at 75 C (Li{sub 8}SiP{sub 4}) and from 6.1(7) x 10{sup -8} Scm{sup -1} at 0 C to 6(1) x 10{sup -6} Scm{sup -1} at 75 C (Li{sub 2}SiP{sub 2}), as determined by impedance measurements. Temperature-dependent solid-state {sup 7}Li NMR spectroscopy revealed low activation energies of about 36 kJ mol{sup -1} for Li{sub 8}SiP{sub 4} and about 47 kJ mol{sup -1} for Li{sub 2}SiP{sub 2}. Both compounds were structurally characterized by X-ray diffraction analysis (single crystal and powder methods) and by {sup 7}Li, {sup 29}Si, and {sup 31}P MAS NMR spectroscopy. Both phases consist of tetrahedral SiP{sub 4} anions and Li counterions. Li{sub 8}SiP{sub 4} contains isolated SiP{sub 4} units surrounded by Li atoms, while Li{sub 2}SiP{sub 2} comprises a three-dimensional network based on corner-sharing SiP{sub 4} tetrahedra, with the Li ions located in cavities and channels. (copyright 2016 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Correlations of the chemical shift on fasly rotating biological solids by means of NMR spectroscopy

    International Nuclear Information System (INIS)

    Herbst, Christian

    2010-01-01

    The basic aim of the thesis was the development and improvement of homo- and heteronuclear feedback sequences for the generation of correlation spectra of the chemical shift. In a first step the possibility of the acquisition of 13 C- 13 correlation spectra of the chemical shift by means of inversion pulses with low RF power factor was studied. Furthermore it was shown that broad-band phase-modulated inversion and universal rotational pulses can be constructed by means of global optimization procedures like the genetic algorithms under regardment of the available RF field strength. By inversion, universal rotational, and 360 pulses as starting values of the optimization efficient homonuclear CN n ν and RN n ν mixing sequences as well as heteronuclear RN n ν s ,ν k feedback sequences were generated. The satisfactory power of the numerically optimized sequences was shown by means of the simulation as well by means of correlation experiments of the chemical shift of L-histidine, L-arginine, and the (CUG) 97 -RNA. This thesis deals furthermore with the possibility to acquire simultaneously different signals with several receivers. By means of numerically optimized RN n ν s ,ν k pulse sequences both 15 N- 13 C and 13 C- 15 N correlation spectra were simultaneously generated. Furthermore it could be shown that the simultaneous acquisition of 3D- 15 N- 13 C- 13 C and 13 C- 15 N-( 1 H)- 1 H correlation spectra is possible. By this in only one measurement process resonance assignments can be met and studies of the global folding performed. A further application of several receivers is the simultaneous acquisition of CHHC, NHHN, NHHC, as well as CHHN spectra. By such experiments it is possible to characterize the hydrogen-bonding pattern and the glycosidic torsion angle χ in RNA. This was demonstrated by means of the (CUG) 97 -RNA. The simultaneous acquisition of all relevant crossing signals of the correlation spectra leads not only to an essential time saving, but

  8. 1H NMR and Multivariate Analysis for Geographic Characterization of Commercial Extra Virgin Olive Oil: A Possible Correlation with Climate Data

    Directory of Open Access Journals (Sweden)

    Domenico Rongai

    2017-11-01

    Full Text Available 1H Nuclear Magnetic Resonance (NMR spectroscopy coupled with multivariate analysis has been applied in order to investigate metabolomic profiles of more than 200 extravirgin olive oils (EVOOs collected in a period of over four years (2009–2012 from different geographic areas. In particular, commercially blended EVOO samples originating from different Italian regions (Tuscany, Sicily and Apulia, as well as European (Spain and Portugal and non-European (Tunisia, Turkey, Chile and Australia countries. Multivariate statistical analysis (Principal Component Analisys (PCA and Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA applied on the NMR data revealed the existence of marked differences between Italian (in particular from Tuscany, Sicily and Apulia regions and foreign (in particular Tunisian EVOO samples. A possible correlation with available climate data has been also investigated. These results aim to develop a powerful NMR-based tool able to protect Italian olive oil productions.

  9. Communication: Proton NMR dipolar-correlation effect as a method for investigating segmental diffusion in polymer melts

    International Nuclear Information System (INIS)

    Lozovoi, A.; Mattea, C.; Stapf, S.; Herrmann, A.; Rössler, E. A.; Fatkullin, N.

    2016-01-01

    A simple and fast method for the investigation of segmental diffusion in high molar mass polymer melts is presented. The method is based on a special function, called proton dipolar-correlation build-up function, which is constructed from Hahn Echo signals measured at times t and t/2. The initial rise of this function contains additive contributions from both inter- and intramolecular magnetic dipole-dipole interactions. The intermolecular contribution depends on the relative mean squared displacements (MSDs) of polymer segments from different macromolecules, while the intramolecular part reflects segmental reorientations. Separation of both contributions via isotope dilution provides access to segmental displacements in polymer melts at millisecond range, which is hardly accessible by other methods. The feasibility of the method is illustrated by investigating protonated and deuterated polybutadiene melts with molecular mass 196 000 g/mol at different temperatures. The observed exponent of the power law of the segmental MSD is close to 0.32 ± 0.03 at times when the root MSD is in between 45 Å and 75 Å, and the intermolecular proton dipole-dipole contribution to the total proton Hahn Echo NMR signal is larger than 50% and increases with time.

  10. Recent advances in solid state NMR and its application to ceramics

    International Nuclear Information System (INIS)

    Maekawa, Hideki

    2006-01-01

    The basic principles of solid state NMR are explained. Four application examples contained amorphous glass, determination of defects of oxide crystal, nano particle and ionic materials. The structure of inorganic glass is measured by 29 Si, 11 B, 31 P and 23 Na NMR and Magic Angle Spinning NMR (MAS-NMR), chemical species near hydrogen by Cross-Polarization Magic Angle Spinning (CP/MAS) method, and hydrogen by Combined Rotation And Multiple Pulse Spectroscopy (CRAMPS) and MAS-NMR. Hydrous and anhydrous silicate glass with condensed 17 O was measured by 17 O Multi Quantum Magic Angle Spinning (MQ/MAS). 27 Al in slags was analyzed by 27 Al 5Q-MAS. 89 Y NMR spectrum of YSZ (Yttria Stabilization Zirconia, Y 2 O 3 -ZrO 2 ) was explained. The ion transfer phenomena in the electrolyte are observed directly by the solid state NMR. (S.Y.)

  11. Investigation of the chemomarkers correlated with flower colour in different organs of Catharanthus roseus using NMR-based metabolomics.

    Science.gov (United States)

    Pan, Qifang; Dai, Yuntao; Nuringtyas, Tri Rini; Mustafa, Natali Rianika; Schulte, Anna Elisabeth; Verpoorte, Robert; Choi, Young Hae

    2014-01-01

    Flower colour is a complex phenomenon that involves a wide range of secondary metabolites of flowers, for example phenolics and carotenoids as well as co-pigments. Biosynthesis of these metabolites, though, occurs through complicated pathways in many other plant organs. The analysis of the metabolic profile of leaves, stems and roots, for example, therefore may allow the identification of chemomarkers related to the final expression of flower colour. To investigate the metabolic profile of leaves, stems, roots and flowers of Catharanthus roseus and the possible correlation with four flower colours (orange, pink, purple and red). (1) H-NMR and multivariate data analysis were used to characterise the metabolites in the organs. The results showed that flower colour is characterised by a special pattern of metabolites such as anthocyanins, flavonoids, organic acids and sugars. The leaves, stems and roots also exhibit differences in their metabolic profiles according to the flower colour. Plants with orange flowers featured a relatively high level of kaempferol analogues in all organs except roots. Red-flowered plants showed a high level of malic acid, fumaric acid and asparagine in both flowers and leaves, and purple and pink flowering plants exhibited high levels of sucrose, glucose and 2,3-dihydroxy benzoic acid. High concentrations of quercetin analogues were detected in flowers and leaves of purple-flowered plants. There is a correlation between the metabolites specifically associated to the expression of different flower colours and the metabolite profile of other plant organs and it is therefore possible to predict the flower colours by detecting specific metabolites in leaves, stems or roots. This may have interesting application in the plant breeding industry. Copyright © 2013 John Wiley & Sons, Ltd.

  12. The "long tail" of the protein tumbling correlation function: observation by (1)H NMR relaxometry in a wide frequency and concentration range.

    Science.gov (United States)

    Roos, Matthias; Hofmann, Marius; Link, Susanne; Ott, Maria; Balbach, Jochen; Rössler, Ernst; Saalwächter, Kay; Krushelnitsky, Alexey

    2015-12-01

    Inter-protein interactions in solution affect the auto-correlation function of Brownian tumbling not only in terms of a simple increase of the correlation time, they also lead to the appearance of a weak slow component ("long tail") of the correlation function due to a slowly changing local anisotropy of the microenvironment. The conventional protocol of correlation time estimation from the relaxation rate ratio R1/R2 assumes a single-component tumbling correlation function, and thus can provide incorrect results as soon as the "long tail" is of relevance. This effect, however, has been underestimated in many instances. In this work we present a detailed systematic study of the tumbling correlation function of two proteins, lysozyme and bovine serum albumin, at different concentrations and temperatures using proton field-cycling relaxometry combined with R1ρ and R2 measurements. Unlike high-field NMR relaxation methods, these techniques enable a detailed study of dynamics on a time scale longer than the normal protein tumbling correlation time and, thus, a reliable estimate of the parameters of the "long tail". In this work we analyze the concentration dependence of the intensity and correlation time of the slow component and perform simulations of high-field (15)N NMR relaxation data demonstrating the importance of taking the "long tail" in the analysis into account.

  13. Assignment of methyl NMR resonances of a 52 kDa protein with residue-specific 4D correlation maps

    International Nuclear Information System (INIS)

    Mishra, Subrata H.; Frueh, Dominique P.

    2015-01-01

    Methyl groups have become key probes for structural and functional studies by nuclear magnetic resonance. However, their NMR signals cluster in a small spectral region and assigning their resonances can be a tedious process. Here, we present a method that facilitates assignment of methyl resonances from assigned amide groups. Calculating the covariance between sensitive methyl and amide 3D spectra, each providing correlations to C α and C β separately, produces 4D correlation maps directly correlating methyl groups to amide groups. Optimal correlation maps are obtained by extracting residue-specific regions, applying derivative to the dimensions subject to covariance, and multiplying 4D maps stemming from different 3D spectra. The latter procedure rescues weak signals that may be missed in traditional assignment procedures. Using these covariance correlation maps, nearly all assigned isoleucine, leucine, and valine amide resonances of a 52 kDa nonribosomal peptide synthetase cyclization domain were paired with their corresponding methyl groups

  14. High Tech M&As

    DEFF Research Database (Denmark)

    Toppenberg, Gustav

    2013-01-01

    Technology driven industries have seen fast moving technology changes, higher complexity and reduced product life cycles. These emerging trends present challenges for companies in industries where technology is at the forefront. The extant research deals with ‘low-tech’ industries and majority...... of findings are not applicable to the high-tech industry; in fact this industry has many additional challenges. In this study, we aim to explore the process of M&A in the high-tech industry by drawing on extant literature and empirical field work. The paper outlines a research project in progress which...... intends to provide theoretical, empirical and practical contributions in answering the research question: what role does Operations and IT play in creating value in high-tech M&As? The research adds a needed perspective on M&A literature by unveiling unique challenges and opportunities faced by the M...

  15. Correlations of the chemical shift on fasly rotating biological solids by means of NMR spectroscopy; Korrelationen der chemischen Verschiebung an schnell rotierenden biologischen Festkoerpern mittels NMR-Spektroskopie

    Energy Technology Data Exchange (ETDEWEB)

    Herbst, Christian

    2010-04-27

    The basic aim of the thesis was the development and improvement of homo- and heteronuclear feedback sequences for the generation of correlation spectra of the chemical shift. In a first step the possibility of the acquisition of {sup 13}C-{sup 13} correlation spectra of the chemical shift by means of inversion pulses with low RF power factor was studied. Furthermore it was shown that broad-band phase-modulated inversion and universal rotational pulses can be constructed by means of global optimization procedures like the genetic algorithms under regardment of the available RF field strength. By inversion, universal rotational, and 360 pulses as starting values of the optimization efficient homonuclear CN{sub n}{sup {nu}} and RN{sub n}{sup {nu}} mixing sequences as well as heteronuclear RN{sub n}{sup {nu}{sub s},{nu}{sub k}} feedback sequences were generated. The satisfactory power of the numerically optimized sequences was shown by means of the simulation as well by means of correlation experiments of the chemical shift of L-histidine, L-arginine, and the (CUG){sub 97}-RNA. This thesis deals furthermore with the possibility to acquire simultaneously different signals with several receivers. By means of numerically optimized RN{sub n}{sup {nu}{sub s},{nu}{sub k}} pulse sequences both {sup 15}N-{sup 13}C and {sup 13}C-{sup 15}N correlation spectra were simultaneously generated. Furthermore it could be shown that the simultaneous acquisition of 3D-{sup 15}N-{sup 13}C-{sup 13}C and {sup 13}C-{sup 15}N-({sup 1}H)-{sup 1}H correlation spectra is possible. By this in only one measurement process resonance assignments can be met and studies of the global folding performed. A further application of several receivers is the simultaneous acquisition of CHHC, NHHN, NHHC, as well as CHHN spectra. By such experiments it is possible to characterize the hydrogen-bonding pattern and the glycosidic torsion angle {sup {chi}} in RNA. This was demonstrated by means of the (CUG){sub 97

  16. Correlations among experimental and theoretical NMR data to determine the absolute stereochemistry of darcyribeirine, a pentacyclic indole alkaloid isolated from Rauvolfia grandiflora

    Science.gov (United States)

    Cancelieri, Náuvia Maria; Ferreira, Thiago Resende; Vieira, Ivo José Curcino; Braz-Filho, Raimundo; Piló-Veloso, Dorila; Alcântara, Antônio Flávio de Carvalho

    2015-10-01

    Darcyribeirine (1) is a pentacyclic indole alkaloid isolated from Rauvolfia grandiflora. Stereochemistry of 1 was previously proposed based on 1D (coupling constant data) and 2D (NOESY correlations) NMR techniques, having been established a configuration 3R, 15S, and 20R (isomer 1a). Stereoisomers of 1 (i.e., 1a-1h) can be grouped into four sets of enantiomers. Carbon chemical shifts and hydrogen coupling constants were calculated using BLYP/6-31G* theory level for the eight isomers of 1. Calculated NMR data of 1a-1h were correlated with the corresponding experimental data of 1. The best correlations between theoretical and experimental carbon chemical shift data were obtained for the set of enantiomers 1e/1f to structures in the gaseous phase and considering solvent effects (using PCM and explicit models). Similar results were obtained when the same procedure was performed to correlations between theoretical and experimental coupling constant data. Finally, optical rotation calculations indicate 1e as its absolute stereochemistry. Orbital population analysis indicates that the hydrogen bonding between N-H of 1e and DMSO is due to contributions of its frontier unoccupied molecular orbitals, mainly LUMO+1, LUMO+2, and LUMO+3.

  17. 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

  18. Structure and distribution of cross-links in boron-modified phenol-formaldehyde resins designed for soft magnetic composites: a multiple-quantum 11B-11B MAS NMR correlation spectroscopy study

    Czech Academy of Sciences Publication Activity Database

    Kobera, Libor; Czernek, Jiří; Strečková, M.; Urbanová, Martina; Abbrent, Sabina; Brus, Jiří

    2015-01-01

    Roč. 48, č. 14 (2015), s. 4874-4881 ISSN 0024-9297 R&D Projects: GA MŠk(CZ) LD14010 Grant - others:European Commission(XE) COST Action MP1202 HINT Institutional support: RVO:61389013 Keywords : phenol-formaldehyde polymers * boron crosslinks * soft magnetic composites Subject RIV: CD - Macromolecular Chemistry Impact factor: 5.554, year: 2015

  19. Interface induced growth and transformation of polymer-conjugated proto-crystalline phases in aluminosilicate hybrids: a multiple-quantum 23Na-23Na MAS NMR correlation spectroscopy study

    Czech Academy of Sciences Publication Activity Database

    Brus, Jiří; Kobera, Libor; Urbanová, Martina; Doušová, B.; Lhotka, M.; Koloušek, D.; Kotek, Jiří; Čuba, P.; Czernek, Jiří; Dědeček, Jiří

    2016-01-01

    Roč. 32, č. 11 (2016), s. 2787-2797 ISSN 0743-7463 R&D Projects: GA ČR(CZ) GA13-24155S; GA MŠk(CZ) LD14010; GA MŠk(CZ) LO1507 Grant - others:European Commission(XE) COST Action MP1202 HINT Institutional support: RVO:61389013 ; RVO:61388955 Keywords : aluminosilicate hybrids * hybrid geopolymers * interface Subject RIV: CD - Macromolecular Chemistry; CF - Physical ; Theoretical Chemistry (UFCH-W) Impact factor: 3.833, year: 2016

  20. Viscosity of concentrated solutions and of human erythrocyte cytoplasm determined from NMR measurement of molecular correlation times

    International Nuclear Information System (INIS)

    Endre, Z.H.; Kuchel, P.W.

    1986-01-01

    Metabolically active human erythrocytes were incubated with [α- 13 C]glycine which led to the specific enrichment of intracellular glutathione. The cells were then studied using 13 C-NMR in which the longitudinal relaxation times (T 1 ) and nuclear Overhauser enhancements of the free glycine and glutathione were measured. Bulk viscosities of the erythrocyte cytoplasm were measured using Ostwald capillary viscometry. Large differences existed between the latter viscosity estimates and those based upon NMR-T 1 measurements. The authors derived an equation from the theory of the viscosity of concentrated solutions which contains two phenomenological interaction parameters, a 'shape' factor and a 'volume' factor; it was fitted to data relating to the concentration dependence of viscosity measured by both methods. Under various conditions of extracellular osmotic pressure, erythrocytes change volume and thus the viscosity of the intracellular milieu is altered. The volume changes resulted in changes in the T 1 of [α- 13 C]glycine. Conversely, the authors showed that alterations in T 1 , when appropriately calibrated, could be used for monitoring changes in volume of metabolically active cells. (Auth.)

  1. Fluid flow dynamics in MAS systems

    Science.gov (United States)

    Wilhelm, Dirk; Purea, Armin; Engelke, Frank

    2015-08-01

    The turbine system and the radial bearing of a high performance magic angle spinning (MAS) probe with 1.3 mm-rotor diameter has been analyzed for spinning rates up to 67 kHz. We focused mainly on the fluid flow properties of the MAS system. Therefore, computational fluid dynamics (CFD) simulations and fluid measurements of the turbine and the radial bearings have been performed. CFD simulation and measurement results of the 1.3 mm-MAS rotor system show relatively low efficiency (about 25%) compared to standard turbo machines outside the realm of MAS. However, in particular, MAS turbines are mainly optimized for speed and stability instead of efficiency. We have compared MAS systems for rotor diameter of 1.3-7 mm converted to dimensionless values with classical turbomachinery systems showing that the operation parameters (rotor diameter, inlet mass flow, spinning rate) are in the favorable range. This dimensionless analysis also supports radial turbines for low speed MAS probes and diagonal turbines for high speed MAS probes. Consequently, a change from Pelton type MAS turbines to diagonal turbines might be worth considering for high speed applications. CFD simulations of the radial bearings have been compared with basic theoretical values proposing considerably smaller frictional loss values. The discrepancies might be due to the simple linear flow profile employed for the theoretical model. Frictional losses generated inside the radial bearings result in undesired heat-up of the rotor. The rotor surface temperature distribution computed by CFD simulations show a large temperature gradient over the rotor.

  2. Hierarchical MAS based control strategy for microgrid

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Z.; Li, T.; Huang, M.; Shi, J.; Yang, J.; Yu, J. [School of Information Science and Engineering, Yunnan University, Kunming 650091 (China); Xiao, Z. [School of Electrical and Electronic Engineering, Nanyang Technological University, Western Catchment Area, 639798 (Singapore); Wu, W. [Communication Branch of Yunnan Power Grid Corporation, Kunming, Yunnan 650217 (China)

    2010-09-15

    Microgrids have become a hot topic driven by the dual pressures of environmental protection concerns and the energy crisis. In this paper, a challenge for the distributed control of a modern electric grid incorporating clusters of residential microgrids is elaborated and a hierarchical multi-agent system (MAS) is proposed as a solution. The issues of how to realize the hierarchical MAS and how to improve coordination and control strategies are discussed. Based on MATLAB and ZEUS platforms, bilateral switching between grid-connected mode and island mode is performed under control of the proposed MAS to enhance and support its effectiveness. (authors)

  3. Fatty acid synthesis in Xylella fastidiosa: correlations between genome studies, 13C NMR data, and molecular models

    International Nuclear Information System (INIS)

    Osiro, Denise; Muniz, Joao Renato C.; Coleta Filho, Helvecio Della; Alves de Sousa, Alessandra; Machado, Marcos Antonio; Garratt, Richard C.; Colnago, Luiz Alberto

    2004-01-01

    Xylella fastidiosa was the first plant pathogen to have its complete genome sequence elucidated. Routine database analyses suggested that two enzymes essential for fatty acid synthesis were missing, one of these is the holo-acyl-carrier-protein synthase. However, here we demonstrate, using 13 C NMR spectroscopy, that X. fastidiosa is indeed able to synthesize fatty acids from acetate via an apparently conventional metabolic pathway. We further identify a gene product HetI, an alternative phosphopantetheinyl transferase, which we propose to fill the missing link. Homology modeling of HetI shows conservation of the Coenzyme A binding site suggesting it to be an active enzyme and reveals several interesting structural features when compared with the surfactin synthase-activating enzyme, on which the model was built. These include a simplified topology due to N- and C-terminal deletions and the observation of a novel serine ladder

  4. Evidence for Heterodimerization and Functional Interaction of the Angiotensin Type 2 Receptor and the Receptor MAS.

    Science.gov (United States)

    Leonhardt, Julia; Villela, Daniel C; Teichmann, Anke; Münter, Lisa-Marie; Mayer, Magnus C; Mardahl, Maibritt; Kirsch, Sebastian; Namsolleck, Pawel; Lucht, Kristin; Benz, Verena; Alenina, Natalia; Daniell, Nicholas; Horiuchi, Masatsugu; Iwai, Masaru; Multhaup, Gerhard; Schülein, Ralf; Bader, Michael; Santos, Robson A; Unger, Thomas; Steckelings, Ulrike Muscha

    2017-06-01

    The angiotensin type 2 receptor (AT2R) and the receptor MAS are receptors of the protective arm of the renin-angiotensin system. They mediate strikingly similar actions. Moreover, in various studies, AT2R antagonists blocked the effects of MAS agonists and vice versa. Such cross-inhibition may indicate heterodimerization of these receptors. Therefore, this study investigated the molecular and functional interplay between MAS and the AT2R. Molecular interactions were assessed by fluorescence resonance energy transfer and by cross correlation spectroscopy in human embryonic kidney-293 cells transfected with vectors encoding fluorophore-tagged MAS or AT2R. Functional interaction of AT2R and MAS was studied in astrocytes with CX3C chemokine receptor-1 messenger RNA expression as readout. Coexpression of fluorophore-tagged AT2R and MAS resulted in a fluorescence resonance energy transfer efficiency of 10.8 ± 0.8%, indicating that AT2R and MAS are capable to form heterodimers. Heterodimerization was verified by competition experiments using untagged AT2R and MAS. Specificity of dimerization of AT2R and MAS was supported by lack of dimerization with the transient receptor potential cation channel, subfamily C-member 6. Dimerization of the AT2R was abolished when it was mutated at cysteine residue 35. AT2R and MAS stimulation with the respective agonists, Compound 21 or angiotensin-(1-7), significantly induced CX3C chemokine receptor-1 messenger RNA expression. Effects of each agonist were blocked by an AT2R antagonist (PD123319) and also by a MAS antagonist (A-779). Knockout of a single of these receptors made astrocytes unresponsive for both agonists. Our results suggest that MAS and the AT2R form heterodimers and that-at least in astrocytes-both receptors functionally depend on each other. © 2017 American Heart Association, Inc.

  5. Simplifying the complex 1H NMR spectra of fluorine-substituted benzamides by spin system filtering and spin-state selection: multiple-quantum-single-quantum correlation.

    Science.gov (United States)

    Baishya, Bikash; Reddy, G N Manjunatha; Prabhu, Uday Ramesh; Row, T N Guru; Suryaprakash, N

    2008-10-23

    The proton NMR spectra of fluorine-substituted benzamides are very complex (Figure 1) due to severe overlap of (1)H resonances from the two aromatic rings, in addition to several short and long-range scalar couplings experienced by each proton. With no detectable scalar couplings between the inter-ring spins, the (1)H NMR spectra can be construed as an overlap of spectra from two independent phenyl rings. In the present study we demonstrate that it is possible to separate the individual spectrum for each aromatic ring by spin system filtering employing the multiple-quantum-single-quantum correlation methodology. Furthermore, the two spin states of fluorine are utilized to simplify the spectrum corresponding to each phenyl ring by the spin-state selection. The demonstrated technique reduces spectral complexity by a factor of 4, in addition to permitting the determination of long-range couplings of less than 0.2 Hz and the relative signs of heteronuclear couplings. The technique also aids the judicious choice of the spin-selective double-quantum-single-quantum J-resolved experiment to determine the long-range homonuclear couplings of smaller magnitudes.

  6. The flexibility of SIMPSON and SIMMOL for numerical simulations in solid-and liquid-state NMR spectroscopy

    International Nuclear Information System (INIS)

    Vosegaard, T.; Malmendal, A.; Nielsen, N.C.

    2002-01-01

    Addressing the need for numerical simulations in the design and interpretation of advanced solid- and liquid-state NMR experiments, we present a number of novel features for numerical simulations based on the SIMPSON and SIMMOL open source software packages. Major attention is devoted to the flexibility of these Tcl-interfaced programs for numerical simulation of NMR experiments being complicated by demands for efficient powder averaging, large spin systems, and multiple-pulse rf irradiation. These features are exemplified by fast simulation of second-order quadrupolar powder patterns using crystallite interpolation, analysis of rotary resonance triple-quantum excitation for quadrupolar nuclei, iterative fitting of MQ-MAS spectra by combination of SIMIPSON and MINUIT, simulation of multiple-dimensional PISEMA-type correlation experiments for macroscopically oriented membrane proteins, simulation of Hartman-Hahn polarization transfers in liquid-state NMR, and visualization of the spin evolution under complex composite broad-band excitation pulses. (author)

  7. UAV Robust Strategy Control Based on MAS

    Directory of Open Access Journals (Sweden)

    Jian Han

    2014-01-01

    Full Text Available A novel multiagent system (MAS has been proposed to integrate individual UAV (unmanned aerial vehicle to form a UAV team which can accomplish complex missions with better efficiency and effect. The MAS based UAV team control is more able to conquer dynamic situations and enhance the performance of any single UAV. In this paper, the MAS proposed and established combines the reacting and thinking abilities to be an initiative and autonomous hybrid system which can solve missions involving coordinated flight and cooperative operation. The MAS uses BDI model to support its logical perception and to classify the different missions; then the missions will be allocated by utilizing auction mechanism after analyzing dynamic parameters. Prim potential algorithm, particle swarm algorithm, and reallocation mechanism are proposed to realize the rational decomposing and optimal allocation in order to reach the maximum profit. After simulation, the MAS has been proved to be able to promote the success ratio and raise the robustness, while realizing feasibility of coordinated flight and optimality of cooperative mission.

  8. Staphylococcal nuclease active-site amino acids: pH dependence of tyrosines and arginines by 13C NMR and correlation with kinetic studies

    International Nuclear Information System (INIS)

    Grissom, C.G.; Markley, J.L.

    1989-01-01

    The pH and temperature dependence of the kinetic parameters of staphylococcal nuclease have been examined with three p-nitrophenyl phosphate containing DNA analogues that vary as to 3'-substituent. With wild-type (Foggi variant) nuclease (nuclease wt) and the substrates thymidine 3'-phosphate 5'-(p-nitrophenyl phosphate) (PNPdTp), thymidine 3'-methylphosphonate 5'-(p-nitrophenyl phosphate) (PNPdTp Me), and thymidine 5'-(p-nitrophenyl phosphate) (PNPdT), k cat remains nearly constant at 13 min -1 . However, k cat /k m with nuclease wt varies considerably. The data suggests that the inflection k cat /K m with pK a at 9.67 arises from ionization of tyrosine-85, which hydrogen bonds to the divalent 3'-phosphomonester of substrates with this substituent. The enthalpy of ionization of both deprotonation steps in the k cat /K m versus pH profile is 5 kcal/mol. 13 C NMR has been used to determine the pK a values of the arginine and tyrosine residues. The results do not rule out arginine as a candidate for the acidic catalyst that protonates the 5'-ribose alkoxide prior to product release. The phenolic hydroxyl carbon of tyrosine-85 has been assigned by comparing the 13 C NMR spectrum of nuclease wt and nuclease Y85F. This correlation between pK a values along with the absence of other candidates indicates that the ionization of tyrosine-85 is the pK a seen in the k cat /K m vs pH profile for substrates with a divalent 3'-phosphomonester. This conclusion is consistent with the proposed role of tyrosine-85 as a hydrogen-bond donor to the 3'-phosphomonoester of substrates poised for exonucleolytic hydrolysis

  9. Correlation of the antimicrobial activity of salicylaldehydes with broadening of the NMR signal of the hydroxyl proton. Possible involvement of proton exchange processes in the antimicrobial activity.

    Science.gov (United States)

    Elo, Hannu; Kuure, Matti; Pelttari, Eila

    2015-03-06

    Certain substituted salicylaldehydes are potent antibacterial and antifungal agents and some of them merit consideration as potential chemotherapeutic agents against Candida infections, but their mechanism of action has remained obscure. We report here a distinct correlation between broadening of the NMR signal of the hydroxyl proton of salicylaldehydes and their activity against several types of bacteria and fungi. When proton NMR spectra of the compounds were determined using hexadeuterodimethylsulfoxide as solvent and the height of the OH proton signal was measured, using the signal of the aldehyde proton as an internal standard, it was discovered that a prerequisite of potent antimicrobial activity is that the proton signal is either unobservable or relatively very low, i.e. that it is extremely broadened. Thus, none of the congeners whose OH proton signal was high were potent antimicrobial agents. Some congeners that gave a very low OH signal were, however, essentially inactive against the microbes, indicating that although drastic broadening of the OH signal appears to be a prerequisite, also other (so far unknown) factors are needed for high antimicrobial activity. Because broadening of the hydroxyl proton signal is related to the speed of the proton exchange process(es) involving that proton, proton exchange may be involved in the mechanism of action of the compounds. Further studies are needed to analyze the relative importance of different factors (such as electronic effects, strength of the internal hydrogen bond, co-planarity of the ring and the formyl group) that determine the rates of those processes. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  10. Hepatocarcinogenesis tumor grading correlated with in vivo image-guided 1H-NMR spectroscopy in a rat model

    International Nuclear Information System (INIS)

    Towner, Rheal A.; Foley, Lesley M.; Painter, Dorothy M.

    2005-01-01

    Hepatocellular carcinoma (HCC) is a common malignancy worldwide, the occurrence of which is unevenly distributed. Most hepatocellular carcinoma cases present late and have a poor prognosis; therefore, early diagnosis is essential to prolong survival. Differential diagnosis with magnetic resonance imaging (MRI) is difficult. We studied the feasibility of using magnetic resonance spectroscopy (MRS) at 7.0 T for the diagnosis and grading of liver tumors. An animal model of hepatocarcinogenesis was used, which allowed tumor progression from precancerous lesions to hepatocellular carcinomas. This study was focused primarily on the grading of the tumors and its correlation with the ratio between the MRS peaks arising from MRS-detected lipid hydrogens (0.9, 1.3 and 5.3 ppm) and compared to the γ-methylene hydrogens of glutamate (Glu) and glutamine (Gln) which was used as an internal reference (2.4 ppm). The lipid methylene hydrogen (1.3 ppm) to (Glu + Gln) ratio was found to correlate with the formation of differentiated small foci and (precancerous) hepatic nodules, whereas the unsaturated olefinic lipid hydrogen (5.3 ppm) to (Glu + Gln) ratio was able to correlate with the formation of late stage tumors such as adenomas and hepatocellular carcinomas. The results of our study suggest that MRS-detected alterations in lipid metabolism can be correlated with the grading of liver tumor tissue at different stages during the carcinogenesis process

  11. Electronic correlations in the hole-doped superconductor RbFe{sub 2}As{sub 2} probed via {sup 75}As NMR

    Energy Technology Data Exchange (ETDEWEB)

    Molatta, S.; Wosnitza, J. [Hochfeld-Magnetlabor Dresden (HLD), Helmholtz-Zentrum Dresden-Rossendorf (Germany); TU Dresden (Germany); DFG, GRK-1621 (Germany); Zhang, Z.; Dmytriieva, D.; Kuehne, H. [Hochfeld-Magnetlabor Dresden (HLD), Helmholtz-Zentrum Dresden-Rossendorf (Germany); Khim, S.; Grafe, H.J. [IFW Dresden (Germany); Wurmehl, S.; Buechner, B. [TU Dresden (Germany); DFG, GRK-1621 (Germany); IFW Dresden (Germany)

    2016-07-01

    We will present latest {sup 75}As NMR data in the normal state of the stoichiometric superconductor RbFe{sub 2}As{sub 2}. This will be put into context to known results for the heavily hole-doped compound KFe{sub 2}As{sub 2}. The static and dynamic magnetic correlations were probed via measurements of the Knight shift and nuclear spin-lattice relaxation rate in a wide temperature range from 0.3 to 300 K. Although neither a magnetic nor a structural transition were observed down to lowest temperatures, the very close proximity of the ground state to a magnetic instability is indicated by a pronounced Curie-Weiss-like behavior of spin fluctuations. At around 100 K, we find a maximum of the Knight shift and a changing exponent of the temperature-dependent relaxation rate. This is phenomenologically similar to the case of KFe{sub 2}As{sub 2} and was proposed to stem from a incoherence-coherence crossover mechanism of electronic correlations.

  12. CORRELATION ANALYSIS OF IR, 1 H- AND 13 C-NMR SPECTRAL DATA OF N-ALKYL AND N-CYCLOALKYL CYANOACETAMIDES

    Directory of Open Access Journals (Sweden)

    Aleksandar D. Marinković

    2011-09-01

    Full Text Available Linear free energy relationships (LFER were applied to the IR, 1H- and 13C--NMR spectral data in N-alkyl and N-cycloalkyl cyanoacetamides. N-alkyl and N-cycloalkyl cyanocetamides were synthesized from corresponding amine and ethyl cyanoacetate. A number of substituents were employed for alkyl substitution, and fairly good correlations were obtained, using simple Hammett equation. In N-alkyl and N-cycloalkyl cyanoacetamides substituent cause SCS of N-H hydrogen primarily by steric interaction, polar subtituent effect influences SCS shift of C=O carbon, while steric effect of N-alkyl substituent causes IR stretching frequencies of N-H, C=O and CN group. The conformations of investigated compounds have been studied by the use of semiempirical PM6 method, and together with LFER analysis, give a better insight into the influence of such a structure on the transmission of electronic substituent effects. Negative ρ values for several correlations (reverse substituent effect were found.

  13. Pairwise NMR experiments for the determination of protein backbone dihedral angle Φ based on cross-correlated spin relaxation

    International Nuclear Information System (INIS)

    Takahashi, Hideo; Shimada, Ichio

    2007-01-01

    Novel cross-correlated spin relaxation (CCR) experiments are described, which measure pairwise CCR rates for obtaining peptide dihedral angles Φ. The experiments utilize intra-HNCA type coherence transfer to refocus 2-bond J NCα coupling evolution and generate the N (i)-C α (i) or C'(i-1)-C α (i) multiple quantum coherences which are required for measuring the desired CCR rates. The contribution from other coherences is also discussed and an appropriate setting of the evolution delays is presented. These CCR experiments were applied to 15 N- and 13 C-labeled human ubiquitin. The relevant CCR rates showed a high degree of correlation with the Φ angles observed in the X-ray structure. By utilizing these CCR experiments in combination with those previously established for obtaining dihedral angle Ψ, we can determine high resolution structures of peptides that bind weakly to large target molecules

  14. 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

  15. Insight into the local magnetic environments and deuteron mobility in jarosite (AFe3(SO4)2(OD)6, A = K, Na, D3O) and hydronium alunite ((D3O)Al3(SO4)2(OD,OD2)6), from variable temperature 2H MAS NMR spectroscopy

    DEFF Research Database (Denmark)

    Nielsen, Ulla Gro; Heinmaa, Ivo; Samoson, Ago

    2011-01-01

    to the different temperature dependence of their isotropic shifts. An activation energy of 6.3(4) kJ/mol is determined for the D3O+ motion in the isostructural compound D3OAl3(SO4)2(OD)6. Our NMR results support theories that ascribes the spin glass behavior of (H3O)Fe3(SO4)2(OD)6 is to disorder of the D3O+ ion...... and/or a less distorted Fe coordination environment. No sign of proton transfer reactions from the D3O+ ion to the framework is observed....

  16. Correlating the P-31 NMR Chemical Shielding Tensor and the (2)J(P,C) Spin-Spin Coupling Constants with Torsion Angles zeta and alpha in the Backbone of Nucleic Acids

    Czech Academy of Sciences Publication Activity Database

    Benda, Ladislav; Sochorová Vokáčová, Zuzana; Straka, Michal; Sychrovský, Vladimír

    2012-01-01

    Roč. 116, č. 12 (2012), s. 3823-3833 ISSN 1520-6106 R&D Projects: GA ČR GAP205/10/0228; GA ČR GPP208/10/P398; GA ČR GA203/09/2037 Institutional research plan: CEZ:AV0Z40550506 Keywords : nucleic acids * phosphorus NMR * NMR calculations * cross-correlated relaxation * spin–spin coupling constants Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.607, year: 2012

  17. Sensitivity improvement for correlations involving arginine side-chain Nε/Hε resonances in multi-dimensional NMR experiments using broadband 15N 180o pulses

    International Nuclear Information System (INIS)

    Iwahara, Junji; Clore, G. Marius

    2006-01-01

    Due to practical limitations in available 15 N rf field strength, imperfections in 15 N 180 o pulses arising from off-resonance effects can result in significant sensitivity loss, even if the chemical shift offset is relatively small. Indeed, in multi-dimensional NMR experiments optimized for protein backbone amide groups, cross-peaks arising from the Arg guanidino 15 Nε (∼85 ppm) are highly attenuated by the presence of multiple INEPT transfer steps. To improve the sensitivity for correlations involving Arg Nε-Hε groups, we have incorporated 15 N broadband 180 deg. pulses into 3D 15 N-separated NOE-HSQC and HNCACB experiments. Two 15 N-WURST pulses incorporated at the INEPT transfer steps of the 3D 15 N-separated NOE-HSQC pulse sequence resulted in a ∼1.5-fold increase in sensitivity for the Arg Nε-Hε signals at 800 MHz. For the 3D HNCACB experiment, five 15 N Abramovich-Vega pulses were incorporated for broadband inversion and refocusing, and the sensitivity of Arg 1 Hε- 15 Nε- 13 Cγ/ 13 Cδ correlation peaks was enhanced by a factor of ∼1.7 at 500 MHz. These experiments eliminate the necessity for additional experiments to assign Arg 1 Hε and 15 Nε resonances. In addition, the increased sensitivity afforded for the detection of NOE cross-peaks involving correlations with the 15 Nε/ 1 Hε of Arg in 3D 15 N-separated NOE experiments should prove to be very useful for structural analysis of interactions involving Arg side-chains

  18. On the use of ultracentrifugal devices for routine sample preparation in biomolecular magic-angle-spinning NMR.

    Science.gov (United States)

    Mandal, Abhishek; Boatz, Jennifer C; Wheeler, Travis B; van der Wel, Patrick C A

    2017-03-01

    A number of recent advances in the field of magic-angle-spinning (MAS) solid-state NMR have enabled its application to a range of biological systems of ever increasing complexity. To retain biological relevance, these samples are increasingly studied in a hydrated state. At the same time, experimental feasibility requires the sample preparation process to attain a high sample concentration within the final MAS rotor. We discuss these considerations, and how they have led to a number of different approaches to MAS NMR sample preparation. We describe our experience of how custom-made (or commercially available) ultracentrifugal devices can facilitate a simple, fast and reliable sample preparation process. A number of groups have since adopted such tools, in some cases to prepare samples for sedimentation-style MAS NMR experiments. Here we argue for a more widespread adoption of their use for routine MAS NMR sample preparation.

  19. On the use of ultracentrifugal devices for routine sample preparation in biomolecular magic-angle-spinning NMR

    Energy Technology Data Exchange (ETDEWEB)

    Mandal, Abhishek; Boatz, Jennifer C. [University of Pittsburgh School of Medicine, Department of Structural Biology (United States); Wheeler, Travis B. [University of Pittsburgh School of Medicine, Department of Cell Biology (United States); Wel, Patrick C. A. van der, E-mail: vanderwel@pitt.edu [University of Pittsburgh School of Medicine, Department of Structural Biology (United States)

    2017-03-15

    A number of recent advances in the field of magic-angle-spinning (MAS) solid-state NMR have enabled its application to a range of biological systems of ever increasing complexity. To retain biological relevance, these samples are increasingly studied in a hydrated state. At the same time, experimental feasibility requires the sample preparation process to attain a high sample concentration within the final MAS rotor. We discuss these considerations, and how they have led to a number of different approaches to MAS NMR sample preparation. We describe our experience of how custom-made (or commercially available) ultracentrifugal devices can facilitate a simple, fast and reliable sample preparation process. A number of groups have since adopted such tools, in some cases to prepare samples for sedimentation-style MAS NMR experiments. Here we argue for a more widespread adoption of their use for routine MAS NMR sample preparation.

  20. Metabolite Profiling of the Microalgal Diatom Chaetoceros Calcitrans and Correlation with Antioxidant and Nitric Oxide Inhibitory Activities via 1H NMR-Based Metabolomics

    Directory of Open Access Journals (Sweden)

    Awanis Azizan

    2018-05-01

    Full Text Available Microalgae are promising candidate resources from marine ecology for health-improving effects. Metabolite profiling of the microalgal diatom, Chaetoceros calcitrans was conducted by using robust metabolomics tools, namely 1H nuclear magnetic resonance (NMR spectroscopy coupled with multivariate data analysis (MVDA. The unsupervised data analysis, using principal component analysis (PCA, resolved the five types of extracts made by solvents ranging from polar to non-polar into five different clusters. Collectively, with various extraction solvents, 11 amino acids, cholesterol, 6 fatty acids, 2 sugars, 1 osmolyte, 6 carotenoids and 2 chlorophyll pigments were identified. The fatty acids and both carotenoid pigments as well as chlorophyll, were observed in the extracts made from medium polar (acetone, chloroform and non-polar (hexane solvents. It is suggested that the compounds were the characteristic markers that influenced the separation between the clusters. Based on partial least square (PLS analysis, fucoxanthin, astaxanthin, violaxanthin, zeaxanthin, canthaxanthin, and lutein displayed strong correlation to 2,2-diphenyl-1-picrylhydrazyl (DPPH free radical scavenging and nitric oxide (NO inhibitory activity. This metabolomics study showed that solvent extractions are one of the main bottlenecks for the maximum recovery of bioactive microalgal compounds and could be a better source of natural antioxidants due to a high value of metabolites.

  1. Functional Groups Determine Biochar Properties (pH and EC as Studied by Two-Dimensional (13C NMR Correlation Spectroscopy.

    Directory of Open Access Journals (Sweden)

    Xiaoming Li

    Full Text Available While the properties of biochar are closely related to its functional groups, it is unclear under what conditions biochar develops its properties. In this study, two-dimensional (2D (13C nuclear magnetic resonance (NMR correlation spectroscopy was for the first time applied to investigate the development of functional groups and establish their relationship with biochar properties. The results showed that the agricultural biomass carbonized to biochars was a dehydroxylation/dehydrogenation and aromatization process, mainly involving the cleavage of O-alkylated carbons and anomeric O-C-O carbons in addition to the production of fused-ring aromatic structures and aromatic C-O groups. With increasing charring temperature, the mass cleavage of O-alkylated groups and anomeric O-C-O carbons occurred prior to the production of fused-ring aromatic structures. The regression analysis between functional groups and biochar properties (pH and electrical conductivity further demonstrated that the pH and electrical conductivity of rice straw derived biochars were mainly determined by fused-ring aromatic structures and anomeric O-C-O carbons, but the pH of rice bran derived biochars was determined by both fused-ring aromatic structures and aliphatic O-alkylated (HCOH carbons. In summary, this work suggests a novel tool for characterising the development of functional groups in biochars.

  2. 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.

  3. Perspective of MAS in Power System via a Fuzzy Framework

    Directory of Open Access Journals (Sweden)

    S. Razini

    2017-03-01

    Full Text Available Multi agent systems (MAS are popularly used in practice, however; a few studies have looked at MAS capabilities from the power engineering perspective. This paper presents the results of an investigation concerning the compatibility of MAS capabilities in different power engineering categories. Five MAS capabilities and seven power system categories are established. A framework for applying MAS in power engineering is developed. A fuzzy inference system is adopted to evaluate the paper proposed framework. Two approaches, namely simulation and real, are considered for different power categories. The paper shows that MAS capabilities are generally compatible with both approaches, although compatibility of MAS with real approach is more significant. The paper concludes that in the near future MAS is anticipated to be a key important tool in the development of intelligent systems and smart grids in power system. This paper contributes to thinking on perspective of MAS in power System.

  4. Theoretical predictions of the two-dimensional solid-state NMR spectra: a case study of the 13C-1H correlations in metergoline

    Czech Academy of Sciences Publication Activity Database

    Czernek, Jiří; Brus, Jiří

    2013-01-01

    Roč. 586, 24 October (2013), s. 56-60 ISSN 0009-2614 Institutional support: RVO:61389013 Keywords : NMR * shielding * metergoline Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.991, year: 2013

  5. Relaxation-compensated difference spin diffusion NMR for detecting {sup 13}C–{sup 13}C long-range correlations in proteins and polysaccharides

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Tuo; Williams, Jonathan K. [Massachusetts Institute of Technology, Department of Chemistry (United States); Schmidt-Rohr, Klaus [Brandeis University, Department of Chemistry (United States); Hong, Mei, E-mail: meihong@mit.edu [Massachusetts Institute of Technology, Department of Chemistry (United States)

    2015-02-15

    The measurement of long-range distances remains a challenge in solid-state NMR structure determination of biological macromolecules. In 2D and 3D correlation spectra of uniformly {sup 13}C-labeled biomolecules, inter-residue, inter-segmental, and intermolecular {sup 13}C–{sup 13}C cross peaks that provide important long-range distance constraints for three-dimensional structures often overlap with short-range cross peaks that only reflect the covalent structure of the molecule. It is therefore desirable to develop new approaches to obtain spectra containing only long-range cross peaks. Here we show that a relaxation-compensated modification of the commonly used 2D {sup 1}H-driven spin diffusion (PDSD) experiment allows the clean detection of such long-range cross peaks. By adding a z-filter to keep the total z-period of the experiment constant, we compensate for {sup 13}C T{sub 1} relaxation. As a result, the difference spectrum between a long- and a scaled short-mixing time spectrum show only long-range correlation signals. We show that one- and two-bond cross peaks equalize within a few tens of milliseconds. Within ∼200 ms, the intensity equilibrates within an amino acid residue and a monosaccharide to a value that reflects the number of spins in the local network. With T{sub 1} relaxation compensation, at longer mixing times, inter-residue and inter-segmental cross peaks increase in intensity whereas intra-segmental cross-peak intensities remain unchanged relative to each other and can all be subtracted out. Without relaxation compensation, the difference 2D spectra exhibit both negative and positive intensities due to heterogeneous T{sub 1} relaxation in most biomolecules, which can cause peak cancellation. We demonstrate this relaxation-compensated difference PDSD approach on amino acids, monosaccharides, a crystalline model peptide, a membrane-bound peptide and a plant cell wall sample. The resulting difference spectra yield clean multi-bond, inter

  6. Relaxation-compensated difference spin diffusion NMR for detecting 13C–13C long-range correlations in proteins and polysaccharides

    International Nuclear Information System (INIS)

    Wang, Tuo; Williams, Jonathan K.; Schmidt-Rohr, Klaus; Hong, Mei

    2015-01-01

    The measurement of long-range distances remains a challenge in solid-state NMR structure determination of biological macromolecules. In 2D and 3D correlation spectra of uniformly 13 C-labeled biomolecules, inter-residue, inter-segmental, and intermolecular 13 C– 13 C cross peaks that provide important long-range distance constraints for three-dimensional structures often overlap with short-range cross peaks that only reflect the covalent structure of the molecule. It is therefore desirable to develop new approaches to obtain spectra containing only long-range cross peaks. Here we show that a relaxation-compensated modification of the commonly used 2D 1 H-driven spin diffusion (PDSD) experiment allows the clean detection of such long-range cross peaks. By adding a z-filter to keep the total z-period of the experiment constant, we compensate for 13 C T 1 relaxation. As a result, the difference spectrum between a long- and a scaled short-mixing time spectrum show only long-range correlation signals. We show that one- and two-bond cross peaks equalize within a few tens of milliseconds. Within ∼200 ms, the intensity equilibrates within an amino acid residue and a monosaccharide to a value that reflects the number of spins in the local network. With T 1 relaxation compensation, at longer mixing times, inter-residue and inter-segmental cross peaks increase in intensity whereas intra-segmental cross-peak intensities remain unchanged relative to each other and can all be subtracted out. Without relaxation compensation, the difference 2D spectra exhibit both negative and positive intensities due to heterogeneous T 1 relaxation in most biomolecules, which can cause peak cancellation. We demonstrate this relaxation-compensated difference PDSD approach on amino acids, monosaccharides, a crystalline model peptide, a membrane-bound peptide and a plant cell wall sample. The resulting difference spectra yield clean multi-bond, inter-residue and intermolecular correlation peaks

  7. Toward a Rational Design of Bioactive Glasses with Optimal Structural Features: Composition–Structure Correlations Unveiled by Solid-State NMR and MD Simulations

    Science.gov (United States)

    2013-01-01

    The physiological responses of silicate-based bioactive glasses (BGs) are known to depend critically on both the P content (nP) of the glass and its silicate network connectivity (N̅BOSi). However, while the bioactivity generally displays a nonmonotonic dependence on nP itself, recent work suggest that it is merely the net orthophosphate content that directly links to the bioactivity. We exploit molecular dynamics (MD) simulations combined with 31P and 29Si solid-state nuclear magnetic resonance (NMR) spectroscopy to explore the quantitative relationships between N̅BOSi, nP, and the silicate and phosphate speciations in a series of Na2O–CaO–SiO2–P2O5 glasses spanning 2.1 ≤ N̅BOSi ≤ 2.9 and variable P2O5 contents up to 6.0 mol %. The fractional population of the orthophosphate groups remains independent of nP at a fixed N̅BOSi-value, but is reduced slightly as N̅BOSi increases. Nevertheless, P remains predominantly as readily released orthophosphate ions, whose content may be altered essentially independently of the network connectivity, thereby offering a route to optimize the glass bioactivity. We discuss the observed composition-structure links in relation to known composition-bioactivity correlations, and define how Na2O–CaO–SiO2–P2O5 compositions exhibiting an optimal bioactivity can be designed by simultaneously altering three key parameters: the silicate network connectivity, the (ortho)phosphate content, and the nNa/nCa molar ratio. PMID:24364818

  8. Ferromagnetic correlations in Yb based heavy fermions probed by NMR relaxation: YbNi{sub 4}P{sub 2} vs. Yb(Rh,Ir){sub 2}Si{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Baenitz, M.; Sarkar, R.; Khuntia, P.; Krellner, C.; Geibel, C.; Steglich, F. [Max - Planck Institute of Chemical Physics of Solids, 01187 Dresden, Germany (Germany)

    2012-07-01

    Intersite correlations in Ce-based heavy fermion systems close to the quantum critical point separating the magnetic ordered state from the paramagnetic Kondo lattice are in almost all cases predominantly antiferromagnetic (AFM) in nature. The NMR relaxation of these systems show an evolution from localized fluctuations with 1/T{sub 1} nearly constant above the Kondo temperature T{sub K}, to a linear in T Korringa- like behavior with a constant and enhanced (1/T{sub 1}T)- value below T{sub K}. We report on {sup 31}P-NMR results on the ferromagnetic (FM) quantum critical system YbNi{sub 4}P{sub 2} over a wide range in temperature (2-300 K) and field (0.2 - 9 T). Here, {sup 31}(1/T{sub 1}T)(T) does not show such a signature at T{sub K}, instead a continuous increase of (1/T{sub 1}T) down to lowest T is observed. A similar behavior has been reported for YbRh{sub 2}Si{sub 2}, which also exhibits strong FM correlations evidenced by {sup 29}Si - NMR and an enhanced Wilson ratio. Furthermore, in CeFePO, which is likely unique among Ce-based quantum critical system because of its strong FM correlations, (1/T{sub 1}T) also diverges continuously for T {yields}0. This suggests that the difference in the relaxation between most of the Ce systems and the Yb systems is predominantly related to a change from AFM to FM intersite correlations. NMR-results (shift, line width, T{sub 1}) are analyzed and discussed in different models (Korringa, Moriya).

  9. 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)

  10. Solid State NMR Characterization of Complex Metal Hydrides systems for Hydrogen Storage Applications

    Directory of Open Access Journals (Sweden)

    Son-Jong Hwang

    2011-12-01

    Full Text Available Solid state NMR is widely applied in studies of solid state chemistries for hydrogen storage reactions. Use of 11B MAS NMR in studies of metal borohydrides (BH4 is mainly focused, revisiting the issue of dodecaborane formation and observation of 11B{1H} Nuclear Overhauser Effect.

  11. Application of unsymmetrical indirect covariance NMR methods to the computation of the (13)C (15)N HSQC-IMPEACH and (13)C (15)N HMBC-IMPEACH correlation spectra.

    Science.gov (United States)

    Martin, Gary E; Hilton, Bruce D; Irish, Patrick A; Blinov, Kirill A; Williams, Antony J

    2007-10-01

    Utilization of long-range (1)H--(15)N heteronuclear chemical shift correlation has continually grown in importance since the first applications were reported in 1995. More recently, indirect covariance NMR methods have been introduced followed by the development of unsymmetrical indirect covariance processing methods. The latter technique has been shown to allow the calculation of hyphenated 2D NMR data matrices from more readily acquired nonhyphenated 2D NMR spectra. We recently reported the use of unsymmetrical indirect covariance processing to combine (1)H--(13)C GHSQC and (1)H--(15)N GHMBC long-range spectra to yield a (13)C--(15)N HSQC-HMBC chemical shift correlation spectrum that could not be acquired in a reasonable period of time without resorting to (15)N-labeled molecules. We now report the unsymmetrical indirect covariance processing of (1)H--(13)C GHMBC and (1)H--(15)N IMPEACH spectra to afford a (13)C--(15)N HMBC-IMPEACH spectrum that has the potential to span as many as six to eight bonds. Correlations for carbon resonances long-range coupled to a protonated carbon in the (1)H--(13)C HMBC spectrum are transferred via the long-range (1)H--(15)N coupling pathway in the (1)H--(15)N IMPEACH spectrum to afford a much broader range of correlation possibilities in the (13)C--(15)N HMBC-IMPEACH correlation spectrum. The indole alkaloid vincamine is used as a model compound to illustrate the application of the method. (c) 2007 John Wiley & Sons, Ltd.

  12. Fluorine dynamics in BaF2 superionic conductors investigated by NMR

    International Nuclear Information System (INIS)

    Gumann, Patryk

    2008-01-01

    In this work the dynamics of fluorine in solid-state electrolytes having BaF 2 -structure was investigated using three different NMR-methods: field cycling relaxometry, lineshape analysis, and static field gradient NMR. For this purpose a pure BaF 2 crystal, as well as crystals doped with trivalent impurities (LaF 3 ), were studied as a function of temperature. Using MAS NMR it was possible to identify two lines in Ba 0.9 La 0.1 F 2.1 having different chemical shift, and to refer them to the modified crystal structure. On this basis a model for the fluorine lineshape has been developed, taking into account three motional processes characterized by their correlation times. It includes jump diffusion of the fluorine ions among equivalent sites within two crystallographically distinct sublattices, and inter-lattice exchange processes. By measuring frequency and temperature-dependent spin lattice relaxation times, it was possible to gain information about fluorine dynamics on microscopic length scales. An attempt was also made to analyze the data for pure BaF 2 and low admixture concentration samples with a non-exponential correlation function. (orig.)

  13. Fluorine dynamics in BaF{sub 2} superionic conductors investigated by NMR

    Energy Technology Data Exchange (ETDEWEB)

    Gumann, Patryk

    2008-07-01

    In this work the dynamics of fluorine in solid-state electrolytes having BaF{sub 2}-structure was investigated using three different NMR-methods: field cycling relaxometry, lineshape analysis, and static field gradient NMR. For this purpose a pure BaF{sub 2} crystal, as well as crystals doped with trivalent impurities (LaF{sub 3}), were studied as a function of temperature. Using MAS NMR it was possible to identify two lines in Ba{sub 0.9}La{sub 0.1}F{sub 2.1} having different chemical shift, and to refer them to the modified crystal structure. On this basis a model for the fluorine lineshape has been developed, taking into account three motional processes characterized by their correlation times. It includes jump diffusion of the fluorine ions among equivalent sites within two crystallographically distinct sublattices, and inter-lattice exchange processes. By measuring frequency and temperature-dependent spin lattice relaxation times, it was possible to gain information about fluorine dynamics on microscopic length scales. An attempt was also made to analyze the data for pure BaF{sub 2} and low admixture concentration samples with a non-exponential correlation function. (orig.)

  14. Sensitivity and Resolution Enhanced Solid-State NMR for Paramagnetic Systems and Biomolecules under Very Fast Magic Angle Spinning

    KAUST Repository

    Parthasarathy, Sudhakar; Nishiyama, Yusuke; Ishii, Yoshitaka

    2013-01-01

    Recent research in fast magic angle spinning (MAS) methods has drastically improved the resolution and sensitivity of NMR spectroscopy of biomolecules and materials in solids. In this Account, we summarize recent and ongoing developments

  15. The covariance of the differences between experimental and theoretical chemical shifts as an aid for assigning two-dimensional heteronuclear correlation solid-state NMR spectra

    Czech Academy of Sciences Publication Activity Database

    Czernek, Jiří; Brus, Jiří

    2014-01-01

    Roč. 608, 21 July (2014), s. 334-339 ISSN 0009-2614 R&D Projects: GA ČR(CZ) GA14-03636S Institutional support: RVO:61389013 Keywords : NMR * DFT * covariance Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.897, year: 2014

  16. 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

  17. Modification and intercalation of layered zirconium phosphates: a solid-state NMR monitoring.

    Science.gov (United States)

    Bakhmutov, Vladimir I; Kan, Yuwei; Sheikh, Javeed Ahmad; González-Villegas, Julissa; Colón, Jorge L; Clearfield, Abraham

    2017-07-01

    Several layered zirconium phosphates treated with Zr(IV) ions, modified by monomethoxy-polyethyleneglycol-monophosphate and intercalated with doxorubicin hydrochloride have been studied by solid-state MAS NMR techniques. The organic components of the phosphates have been characterized by the 13 C{ 1 H} CP MAS NMR spectra compared with those of initial compounds. The multinuclear NMR monitoring has provided to establish structure and covalent attachment of organic/inorganic moieties to the surface and interlayer spaces of the phosphates. The MAS NMR experiments including kinetics of proton-phosphorus cross polarization have resulted in an unusual structure of zirconium phosphate 6 combining decoration of the phosphate surface by polymer units and their partial intercalation into the interlayer space. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  18. Solid-state 13C magic angle spinning NMR spectroscopy characterization of particle size structural variations in synthetic nanodiamonds

    International Nuclear Information System (INIS)

    Alam, Todd M.

    2004-01-01

    Solid-state 13 C magic angle spinning (MAS) NMR spectroscopy has been used to quantify the different carbon species observed in synthetically produced nanodiamonds. Two different diamond-like carbon species were observed using 13 C MAS NMR, which have been attributed to a highly ordered crystalline diamond phase and a disordered crystalline diamond phase. The relative ratio of these different diamond phases was found to vary with the particle size of the nanodiamond materials

  19. Novel NMR tools to study structure and dynamics of biomembranes.

    Science.gov (United States)

    Gawrisch, Klaus; Eldho, Nadukkudy V; Polozov, Ivan V

    2002-06-01

    Nuclear magnetic resonance (NMR) studies on biomembranes have benefited greatly from introduction of magic angle spinning (MAS) NMR techniques. Improvements in MAS probe technology, combined with the higher magnetic field strength of modern instruments, enables almost liquid-like resolution of lipid resonances. The cross-relaxation rates measured by nuclear Overhauser enhancement spectroscopy (NOESY) provide new insights into conformation and dynamics of lipids with atomic-scale resolution. The data reflect the tremendous motional disorder in the lipid matrix. Transfer of magnetization by spin diffusion along the proton network of lipids is of secondary relevance, even at a long NOESY mixing time of 300 ms. MAS experiments with re-coupling of anisotropic interactions, like the 13C-(1)H dipolar couplings, benefit from the excellent resolution of 13C shifts that enables assignment of the couplings to specific carbon atoms. The traditional 2H NMR experiments on deuterated lipids have higher sensitivity when conducted on oriented samples at higher magnetic field strength. A very large number of NMR parameters from lipid bilayers is now accessible, providing information about conformation and dynamics for every lipid segment. The NMR methods have the sensitivity and resolution to study lipid-protein interaction, lateral lipid organization, and the location of solvents and drugs in the lipid matrix.

  20. Dynamic inter-subunit interactions in thermophilic F1-ATPase subcomplexes studied by cross-correlated relaxation-enhanced polarization transfer NMR

    International Nuclear Information System (INIS)

    Kobayashi, Masumi; Yagi, Hiromasa; Yamazaki, Toshio; Yoshida, Masasuke; Akutsu, Hideo

    2008-01-01

    F 1 -ATPase is a unique enzyme in terms of its rotational catalytic activity. The smallest unit showing this property is the α 3 β 3 γ complex (351 kDa). For investigation of such a huge system by means of solution NMR, we have explored a suitable NMR method using F 1 -ATPase subcomplexes from a thermophilic Bacillus PS3 including an α 3 β 3 hexamer (319 kDa). Pulse sequences for large molecules, effects of deuteration and simplification of the spectra were examined in this work. Since the β subunit includes the catalytic site, this was the target of the analysis in this work. The combination of [ 15 N, 1 H]-CRINEPT-HMQC-[ 1 H]-TROSY, deuteration of both α and β subunits, and segmental isotope-labeling was found essential to analyze such a huge and complex molecular system. Utilizing this method, subcomplexes composed of α and β subunits were investigated in terms of inter-subunit interactions. It turned out that there is equilibrium among monomers, heterodimers and the α 3 β 3 hexamers in solution. The rate of exchange between the dimer and hexamer is in the slow regime on the NMR time scale. In chemical shift perturbation experiments, the N-terminal domain was found to be involved in strong inter-subunit interactions. In contrast, the C-terminal domain was found to be mobile even in the hexamer

  1. The structure of poly(carbonsuboxide) on the atomic scale: a solid-state NMR study.

    Science.gov (United States)

    Schmedt auf der Günne, Jörn; Beck, Johannes; Hoffbauer, Wilfried; Krieger-Beck, Petra

    2005-07-18

    In this contribution we present a study of the structure of amorphous poly(carbonsuboxide) (C3O2)x by 13C solid-state NMR spectroscopy supported by infrared spectroscopy and chemical analysis. Poly(carbonsuboxide) was obtained by polymerization of carbonsuboxide C3O2, which in turn was synthesized from malonic acid bis(trimethylsilylester). Two different 13C labeling schemes were applied to probe inter- and intramonomeric bonds in the polymer by dipolar solid-state NMR methods and also to allow quantitative 13C MAS NMR spectra. Four types of carbon environments can be distinguished in the NMR spectra. Double-quantum and triple-quantum 2D correlation experiments were used to assign the observed peaks using the through-space and through-bond dipolar coupling. In order to obtain distance constraints for the intermonomeric bonds, double-quantum constant-time experiments were performed. In these experiments an additional filter step was applied to suppress contributions from not directly bonded 13C,13C spin pairs. The 13C NMR intensities, chemical shifts, connectivities and distances gave constraints for both the polymerization mechanism and the short-range order of the polymer. The experimental results were complemented by bond lengths predicted by density functional theory methods for several previously suggested models. Based on the presented evidence we can unambiguously exclude models based on gamma-pyronic units and support models based on alpha-pyronic units. The possibility of planar ladder- and bracelet-like alpha-pyronic structures is discussed.

  2. 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)

  3. Structural characteristics of marine sedimentary humic acids by CP/MAS sup(13)C NMR spectroscopy

    Digital Repository Service at National Institute of Oceanography (India)

    Sardessai, S.; Wahidullah, S.

    quino- nes or semiquinones which exhibit 13C resonance at around 195 ppm. Free radicals of semiquinone type have been reported from the aquatic environment [2]. Spectra of all the four samples show absorption at 195 ppm. The total acidity of marine..., significant resonance at 55 ppm (8.9) from aromatic methoxy carbon suggests that phenol is present mostly as methyl ether and not as free phenol. The signal at 55 ppm is also attributed to aliphatic carbon adjacent to the amino functional group as in amino...

  4. HR-MAS NMR metabolomics of 'Swingle' citrumelo rootstock genetically modified to overproduce proline.

    Science.gov (United States)

    de Oliveira, Caroline S; Carlos, Eduardo F; Vieira, Luiz G E; Lião, Luciano M; Alcantara, Glaucia B

    2014-08-01

    The accumulation of proline is a typical physiological response to abiotic stresses in higher plants. 'Swingle' citrumelo, an important rootstock for citrus production, has been modified with a mutated Δ(1)-pyrroline-5-carboxylate synthetase gene (VaP5CSF129A) linked to the cauliflower mosaic virus 35S promoter to induce the overproduction of free proline. This paper presents a comparative metabolomic study of nontransgenic versus transgenic 'Swingle' citrumelo plants with high endogenous proline. (1)H high-resolution magic angle spinning nuclear magnetic resonance spectroscopy and multivariate analysis showed significant differences in some metabolites between the nontransgenic and transgenic leaves and roots. The overproduction of proline has reduced the sucrose content in transgenic leaves, revealing a metabolic cost for these plants. In roots, the high level of free proline acts for the adjustment of cation-anion balance, causing the reduction of acetic acid content. The same sucrose level in roots indicates that they can be considered as sucrose sink. Similar behavior may be waited for fruits produced on transgenic rootstock. Copyright © 2014 John Wiley & Sons, Ltd.

  5. Characterization of Silicon Nanocrystal Surfaces by Multidimensional Solid-State NMR Spectroscopy

    International Nuclear Information System (INIS)

    Hanrahan, Michael P.; Fought, Ellie L.; Windus, Theresa L.; Wheeler, Lance M.; Anderson, Nicholas C.

    2017-01-01

    The chemical and photophysical properties of silicon nanocrystals (Si NCs) are strongly dependent on the chemical composition and structure of their surfaces. Here we use fast magic angle spinning (MAS) and proton detection to enable the rapid acquisition of dipolar and scalar 2D 1 H– 29 Si heteronuclear correlation (HETCOR) solid-state NMR spectra and reveal a molecular picture of hydride-terminated and alkyl-functionalized surfaces of Si NCs produced in a nonthermal plasma. 2D 1 H– 29 Si HETCOR and dipolar 2D 1 H– 1 H multiple-quantum correlation spectra illustrate that resonances from surface mono-, di-, and trihydride groups cannot be resolved, contrary to previous literature assignments. Instead the 2D NMR spectra illustrate that there is large distribution of 1 H and 29 Si chemical shifts for the surface hydride species in both the as-synthesized and functionalized Si NCs. However, proton-detected 1 H– 29 Si refocused INEPT experiments can be used to unambiguously differentiate NMR signals from the different surface hydrides. Varying the 29 Si evolution time in refocused INEPT experiments and fitting the oscillation of the NMR signals allows for the relative populations of the different surface hydrides to be estimated. This analysis confirms that monohydride species are the predominant surface species on the as-synthesized Si NCs. A reduction in the populations of the di- and trihydrides is observed upon functionalization with alkyl groups, consistent with our previous hypothesis that the trihydride, or silyl (*SiH 3 ), group is primarily responsible for initiating surface functionalization reactions. Density functional theory (DFT) calculations were used to obtain quantum chemical structural models of the Si NC surface and reproduce the observed 1 H and 29 Si chemical shifts. Furthermore, the approaches outlined here will be useful to obtain a more detailed picture of surface structures for Si NCs and other hydride-passivated nanomaterials.

  6. Measurements of relative chemical shift tensor orientations in solid-state NMR: new slow magic angle spinning dipolar recoupling experiments.

    Science.gov (United States)

    Jurd, Andrew P S; Titman, Jeremy J

    2009-08-28

    Solid-state NMR experiments can be used to determine conformational parameters, such as interatomic distances and torsion angles. The latter can be obtained from measurements of the relative orientation of two chemical shift tensors, if the orientation of these with respect to the surrounding bonds is known. In this paper, a new rotor-synchronized magic angle spinning (MAS) dipolar correlation experiment is described which can be used in this way. Because the experiment requires slow MAS rates, a novel recoupling sequence, designed using symmetry principles, is incorporated into the mixing period. This recoupling sequence is based in turn on a new composite cyclic pulse referred to as COAST (for combined offset and anisotropy stabilization). The new COAST-C7(2)(1) sequence is shown to give good theoretical and experimental recoupling efficiency, even when the CSA far exceeds the MAS rate. In this regime, previous recoupling sequences, such as POST-C7(2)(1), exhibit poor recoupling performance. The effectiveness of the new method has been explored by a study of the dipeptide L-phenylalanyl-L-phenylalanine.

  7. Human- and computer-accessible 2D correlation data for a more reliable structure determination of organic compounds. Future roles of researchers, software developers, spectrometer managers, journal editors, reviewers, publisher and database managers toward artificial-intelligence analysis of NMR spectra.

    Science.gov (United States)

    Jeannerat, Damien

    2017-01-01

    The introduction of a universal data format to report the correlation data of 2D NMR spectra such as COSY, HSQC and HMBC spectra will have a large impact on the reliability of structure determination of small organic molecules. These lists of assigned cross peaks will bridge signals found in NMR 1D and 2D spectra and the assigned chemical structure. The record could be very compact, human and computer readable so that it can be included in the supplementary material of publications and easily transferred into databases of scientific literature and chemical compounds. The records will allow authors, reviewers and future users to test the consistency and, in favorable situations, the uniqueness of the assignment of the correlation data to the associated chemical structures. Ideally, the data format of the correlation data should include direct links to the NMR spectra to make it possible to validate their reliability and allow direct comparison of spectra. In order to take the full benefits of their potential, the correlation data and the NMR spectra should therefore follow any manuscript in the review process and be stored in open-access database after publication. Keeping all NMR spectra, correlation data and assigned structures together at all time will allow the future development of validation tools increasing the reliability of past and future NMR data. This will facilitate the development of artificial intelligence analysis of NMR spectra by providing a source of data than can be used efficiently because they have been validated or can be validated by future users. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  8. DAMPAK KEBIJAKAN PEMERINTAH TERHADAP KOMODITAS PISANG MAS KIRANA

    Directory of Open Access Journals (Sweden)

    Ariq Dewi Maharani

    2016-10-01

    Full Text Available ABSTRAKPenelitian ini bertujuan untuk menganalisis aspek profitabilitas pisang mas Kirana di Kabupaten Lumajang, dan menganalisis dampak kebijakan pemerintah terhadap pisang mas Kirana di Kabupaten Lumajang. Penentuan lokasi dilakukan secara sengaja (purposive method di Kabupaten Lumajang. Data yang digunakan meliputi data primer dan data sekunder. Analisa data menggunakan Policy Analysis Matrix (PAM untuk menganalisis aspek profitabilitas dan dampak kebijakan pemerintah terhadap pisang mas Kirana. Hasil penelitian menunjukkan bahwa Komoditas pisang mas Kirana menguntungkan secara finansial dan ekonomi yang ditunjukkan dengan keuntungan privat (PP Rp 10.444.911,8 per hektar dan keuntungan sosial (SP sebesar Rp 23.108.983,7 per hektar. Keuntungan privat pisang mas Kirana lebih kecil daripada keuntungan sosialnya (PPmas Kirana, terdapat dampak kebijakan subsidi terhadap harga-harga input pada usahatani pisang mas Kirana; masih belum ada lembaga yang dapat memberikan pelayanan yang kompetitif serta informasi yang lengkap dan rendahnya harga beli pisang mas Kirana di dalam negeri. ABSTRACTThe purpose of this research for: to analyse the aspect of profitability Kirana Mas banana and to analyse impact of government policy on Kirana Mas banana in Lumajang District. Determination of location was done intentionally or purposive method in Lumajang regency. The data that was used covering primary data and secondary data. Data analysis used Policy Analysis Matrix (PAM for knowing of profitability aspect and impact of government policy on Kirana Mas banana. The results showed that Commodity of Kirana Mas banana has financially and economically beneficial, shown by private profit (PP Rp 10,444,911.8 per hectare and social benefits (SP Rp 23,108,983.7 per hectare. Private profits of “Kirana mas” banana are smaller than social benefit (PP

  9. PEMANFAATAN TANAMAN ATRAKTAN MENGENDALIKAN HAMA KEONG MAS PADI

    Directory of Open Access Journals (Sweden)

    Ameilia Zuliyanti Siregar

    2018-01-01

    In Indonesia, many plantation as use as beneficial plants. This study aims to obtain an effective formula that can be used as a biopesticide to control snail pests during the vegetative phase from May to July 2017 using random non-factorial methods at two rice planting locations in the Village Lae parira, Dairi, North Sumatra. Design with 6 treatments and 3 replicates (ie control, neem leaves (Azadirachta indica, tobacco leaf (Nicotiana tabacum, sweet potato leaf (Manihot glaziovii, noni fruit, Morinda citrifolia, and betel nut (Areca catechu and papaya (Carica papaya as an eco-friendly herbaceous and biopesticide. Based on the study recorded in sampling for 7 days with 6 treatments had significant effect on the percentage affected by the clump of rice attacked and the percentage of death. Pearson correlation value recorded percentage of death and percentage of impacted  showed a very significant relationship. Neem is the best biopesticide in controlling mollusicides, followed by betel nuts, tobacco, poisonous yams and noni. Death of 100% snail mas will prevent damage to the clump of rice plants Dairi, North Sumatra. All biopesticide treatments were tested to control snail pests in rice plants that will increase agicultural productivity in maintaining food security in Dairi, North Sumatra.

  10. CAMEX-4 ER-2 MODIS AIRBORNE SIMULATOR (MAS) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The MODIS Airborne Simulator (MAS) is an airborne scanning spectrometer that acquires high spatial resolution imagery of cloud and surface features from its vantage...

  11. Multinuclear solid-state high-resolution and C-13 -{Al-27} double-resonance magic-angle spinning NMR studies on aluminum alkoxides

    NARCIS (Netherlands)

    Abraham, A.; Prins, R.; Bokhoven, J.A. van; Eck, E.R.H. van; Kentgens, A.P.M.

    2006-01-01

    A combination of Al-27 magic-angle spinning (MAS)/multiple quantum (MQ)-MAS, C-13-H-1 CPMAS, and C-13-{Al-27} transfer of population in double-resonance (TRAPDOR) nuclear magnetic resonance (NMR) were used for the structural elucidation of the aluminum alkoxides aluminum ethoxide, aluminum

  12. Experimental solid state NMR of gas hydrates : problems and solutions

    Energy Technology Data Exchange (ETDEWEB)

    Moudrakovski, I.; Lu, H.; Ripmeester, J. [National Research Council of Canada, Ottawa, ON (Canada). Steacie Inst. for Molecular Sciences; Kumar, R.; Susilo, R. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Chemical and Biological Engineering; Luzi, M. [GeoForschungsZentrum Potsdam, Potsdam (Germany)

    2008-07-01

    Solid State NMR is a suitable spectroscopic technique for hydrate research for several reasons, including its capability to distinguish between different structural types of hydrates, its quantitative nature and potential for both in-situ and time resolved experiments. This study illustrated the applications of solid state NMR for compositional and structural studies of clathrate hydrates, with particular emphasis on experimental techniques and potential ways to overcome technical difficulties. In order to use the method to its full capacity, some instrumental developments are needed to adapt it to the specific experimental requirements of hydrate studies, such as very low temperatures and high pressures. This presentation discussed the quantification of the Carbon-13 spectra with examples from natural and synthetic hydrates prepared from multi-component mixtures of hydrocarbons. The main approach used for the first two examples was Carbon-13 NMR with Magic Angle Spinning (MAS) at -100 degrees C. The detailed characterization of mixed hydrogen hydrates required low temperature hydrogen MAS. The quantification problems encountered during these experiments were also discussed. The purpose of these recent experimental developments was to prompt wider application of Solid State NMR in hydrate research. NMR proved to be a viable method for analyzing the composition and structure of multi-component mixed gas hydrates; characterizing natural gas hydrates; and, evaluating the formation conditions and properties of mixed hydrogen hydrates. The limitations of the method were highlighted and sensible choices of experimental conditions and techniques that ensure accurate results were discussed. 34 refs., 10 figs.

  13. 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...

  14. The structure of phosphate and borosilicate glasses and their structural evolution at high temperatures as studied with solid state NMR spectroscopy: Phase separation, crystallisation and dynamic species exchange

    International Nuclear Information System (INIS)

    Wegner, S.; Van Wullen, L.; Tricot, G.; Tricot, G.

    2010-01-01

    In this contribution we present an in-depth study of the network structure of different phosphate based and borosilicate glasses and its evolution at high temperatures. Employing a range of advanced solid state NMR methodologies, complemented by the results of XPS, the structural motifs on short and intermediate length scales are identified. For the phosphate based glasses, at temperatures above the glass transition temperature Tg, structural relaxation processes and the devitrification of the glasses were monitored in situ employing MAS NMR spectroscopy and X-ray diffraction. Dynamic species exchange involving rapid P-O-P and P-O-Al bond breaking and reforming was observed employing in situ 27 Al and 31 P MAS NMR spectroscopy and could be linked to viscous flow. For the borosilicate glasses, an atomic scale investigation of the phase separation processes was possible in a combined effort of ex situ NMR studies on glass samples with different thermal histories and in situ NMR studies using high temperature MAS NMR spectroscopy including 11 B MAS, 29 Si MAS and in situ 29 Si{ 11 B} REAPDOR NMR spectroscopy. (authors)

  15. Increased vascular sympathetic modulation in mice with Mas receptor deficiency

    Science.gov (United States)

    Rabello Casali, Karina; Ravizzoni Dartora, Daniela; Moura, Marina; Bertagnolli, Mariane; Bader, Michael; Haibara, Andrea; Alenina, Natalia; Irigoyen, Maria Claudia; Santos, Robson A

    2016-01-01

    Introduction: The angiotensin-converting enzyme 2 (ACE2)/angiotensin (Ang)-(1–7)/Mas axis could modulate the heart rate (HR) and blood pressure variabilities (BPV) which are important predictors of cardiovascular risk and provide information about the autonomic modulation of the cardiovascular system. Therefore we investigated the effect of Mas deficiency on autonomic modulation in wild type and Mas-knockout (KO) mice. Methods: Blood pressure was recorded at high sample rate (4000 Hz). Stationary sequences of 200–250 beats were randomly chosen. Frequency domain analysis of HR and BPV was performed with an autoregressive algorithm on the pulse interval sequences and on respective systolic sequences. Results: The KO group presented an increase of systolic arterial pressure (SAP; 127.26±11.20 vs 135.07±6.98 mmHg), BPV (3.54±1.54 vs 5.87±2.12 mmHg2), and low-frequency component of systolic BPV (0.12±0.11 vs 0.47±0.34 mmHg2). Conclusions: The deletion of Mas receptor is associated with an increase of SAP and with an increased BPV, indicating alterations in autonomic control. Increase of sympathetic vascular modulation in absence of Mas evidences the important role of Ang-(1–7)/Mas on cardiovascular regulation. Moreover, the absence of significant changes in HR and HRV can indicate an adaptation of autonomic cardiac balance. Our results suggest that the Ang-(1–7)/Mas axis seems more important in autonomic modulation of arterial pressure than HR. PMID:27080540

  16. Numerical design of RNnν symmetry-based RF pulse schemes for recoupling and decoupling of nuclear spin interactions at high MAS frequencies

    International Nuclear Information System (INIS)

    Herbst, Christian; Herbst, Jirada; Leppert, Joerg; Ohlenschlaeger, Oliver; Goerlach, Matthias; Ramachandran, Ramadurai

    2009-01-01

    An approach for the efficient implementation of RN n ν symmetry-based pulse schemes that are often employed for recoupling and decoupling of nuclear spin interactions in biological solid state NMR investigations is demonstrated at high magic-angle spinning frequencies. RF pulse sequences belonging to the RN n ν symmetry involve the repeated application of the pulse sandwich {R φ R -φ }, corresponding to a propagator U RF = exp(-i4φI z ), where φ = πν/N and R is typically a pulse that rotates the nuclear spins through 180 o about the x-axis. In this study, broadband, phase-modulated 180 o pulses of constant amplitude were employed as the initial 'R' element and the phase-modulation profile of this 'R' element was numerically optimised for generating RN n ν symmetry-based pulse schemes with satisfactory magnetisation transfer characteristics. At representative MAS frequencies, RF pulse sequences were implemented for achieving 13 C- 13 C double-quantum dipolar recoupling and through bond scalar coupling mediated chemical shift correlation and evaluated via numerical simulations and experimental measurements. The results from these investigations are presented here

  17. Recoupling and decoupling of nuclear spin interactions at high MAS frequencies: numerical design of CNnν symmetry-based RF pulse schemes

    International Nuclear Information System (INIS)

    Herbst, Christian; Herbst, Jirada; Kirschstein, Anika; Leppert, Joerg; Ohlenschlaeger, Oliver; Goerlach, Matthias; Ramachandran, Ramadurai

    2009-01-01

    The CN n ν class of RF pulse schemes, commonly employed for recoupling and decoupling of nuclear spin interactions in magic angle spinning solid state NMR studies of biological systems, involves the application of a basic 'C' element corresponding to an RF cycle with unity propagator. In this study, the design of CN n ν symmetry-based RF pulse sequences for achieving 13 C- 13 C double-quantum dipolar recoupling and through bond scalar coupling mediated 13 C- 13 C chemical shift correlation has been examined at high MAS frequencies employing broadband, constant-amplitude, phase-modulated basic 'C' elements. The basic elements were implemented as a sandwich of a small number of short pulses of equal duration with each pulse characterised by an RF phase value. The phase-modulation profile of the 'C' element was optimised numerically so as to generate efficient RF pulse sequences. The performances of the sequences were evaluated via numerical simulations and experimental measurements and are presented here

  18. NMR spectroscopy applied to the eye: Drugs and metabolic studies

    Energy Technology Data Exchange (ETDEWEB)

    Saether, Oddbjoern

    2005-07-01

    NMR spectroscopy has been extensively applied in biomedical research during the last decades. It has proved to be an analytical tool of great value. From being mainly used in chemistry, technological developments have expanded the application of NMR spectroscopy to a great wealth of disciplines. With this method, biochemical information can be obtained by analysing tissue extracts. Moreover, NMR spectroscopy is increasingly employed for pharmacokinetic studies and analysis of biofluids. Technological progress has provided increased sensitivity and resolution in the spectra, which enable even more of the complexity of biological samples to be elucidated. With the implementation of high-resolution magic angle spinning (HR-MAS) NMR spectroscopy in biomedicine, intact tissue samples or biopsies can be investigated. Thus, NMR spectroscopy has an ever-increasing impact in metabolic screening of human samples and in animal models, and methods are also increasingly realised in vivo. The present work, NMR spectroscopy applied to eye research, consists of two main parts. Firstly, the feasibility to monitor fluorinated ophthalmic drugs directly in the eye was assessed. Secondly, HR-MAS H1 NMR spectroscopy was applied for metabolic profiling of the anterior eye segment, specifically to analyse metabolic changes in intact corneal and lenticular samples after cataractogenic insults. This work included metabonomics with the application of pattern recognition methods to analyse HR-MAS spectra of eye tissues. Optimisation strategies were explored for F19 NMR detection of fluorinated drugs in a phantom eye. S/N gains in F19 NMR spectroscopy were achieved by implementing time-share H1 decoupling at 2.35 T. The method is advantageous for compounds displaying broad spectral coupling patterns, though detection of drugs at concentrations encountered in the anterior eye segment after topical application was not feasible. Higher magnetic fields and technological improvements could enable

  19. NMR spectroscopy applied to the eye: Drugs and metabolic studies

    International Nuclear Information System (INIS)

    Saether, Oddbjoern

    2005-01-01

    NMR spectroscopy has been extensively applied in biomedical research during the last decades. It has proved to be an analytical tool of great value. From being mainly used in chemistry, technological developments have expanded the application of NMR spectroscopy to a great wealth of disciplines. With this method, biochemical information can be obtained by analysing tissue extracts. Moreover, NMR spectroscopy is increasingly employed for pharmacokinetic studies and analysis of biofluids. Technological progress has provided increased sensitivity and resolution in the spectra, which enable even more of the complexity of biological samples to be elucidated. With the implementation of high-resolution magic angle spinning (HR-MAS) NMR spectroscopy in biomedicine, intact tissue samples or biopsies can be investigated. Thus, NMR spectroscopy has an ever-increasing impact in metabolic screening of human samples and in animal models, and methods are also increasingly realised in vivo. The present work, NMR spectroscopy applied to eye research, consists of two main parts. Firstly, the feasibility to monitor fluorinated ophthalmic drugs directly in the eye was assessed. Secondly, HR-MAS H1 NMR spectroscopy was applied for metabolic profiling of the anterior eye segment, specifically to analyse metabolic changes in intact corneal and lenticular samples after cataractogenic insults. This work included metabonomics with the application of pattern recognition methods to analyse HR-MAS spectra of eye tissues. Optimisation strategies were explored for F19 NMR detection of fluorinated drugs in a phantom eye. S/N gains in F19 NMR spectroscopy were achieved by implementing time-share H1 decoupling at 2.35 T. The method is advantageous for compounds displaying broad spectral coupling patterns, though detection of drugs at concentrations encountered in the anterior eye segment after topical application was not feasible. Higher magnetic fields and technological improvements could enable

  20. KINERJA USAHA TANAMAN HIAS POTONG PT PESONA DAUN MAS ASRI

    Directory of Open Access Journals (Sweden)

    Muhamad Arief Bangun Sanjaya

    2017-01-01

    Full Text Available Pesona Daun Mas Asri is a company in cut flowers  and leaves cultivation. The  achievement is shown by the performance of the company. The overall company’s performance contributes in developing the company’s vision. Balanced score card is a management tool used to observe and maintain the stability between financial indicators (financial perspective and non financial indicators (customer, business internal process, growth and learning.  The objective of the journal is to plan the performance of the company using balanced scorecard approach, analyze and calculate the vision, mission and strategy implemented by Pesona Daun Mas in it business activity..  The result for every strategic target shows that the performance of Pesona Daun Mas is excellent with the achieved score of 78,04%.  However the target for the selling growth level and marketing activities are classified as average which means that it still needs to be developed.   Keywords:  balanced scorecard, performance evaluation, KPI performance index, ornamental plants cutAbstrakPesona Daun Mas Asri merupakan perusahaan yang bergerak dalam bidang budi daya bunga potong dan daun potong. Pencapaian dalam menjalankan sebuah perusahaan dapat dilihat dari kinerja perusahaan tersebut.Kinerja perusahaan Pesona Daun Mas Asri secara keseluruhan dapat berkontribusi untuk mengembangkan perusahaan dalam mencapai visi. Balanced scorecard adalah salah satu alat manajemen yang dapat melihat dan menjaga keseimbangan antara indikator keuangan (perspektif keuangan dan indikator non-keuangan (pelanggan, proses bisnisinternal, pertumbuhan dan pembelajaran. Tujuan dari jurnal ini adalah untuk merancang pengukuran kinerja perusahaan dengan pendekatan Balanced scorecard. Penelitian ini juga bertujuan menganalisis dan mengukur pelaksanaan visi, misi dan strategi yang dijalankan oleh Pesona Daun Mas Asri dalam kegiatan bisnisnya. Selain itu, memberikan saran dan rekomendasi, serta merumuskan implikasi

  1. MAS2-8 radar and digital control unit

    Science.gov (United States)

    Oberg, J. M.; Ulaby, F. T.

    1974-01-01

    The design of the MAS 2-8 (2 to 8 GHz microwave-active spectrometer), a ground-based sensor system, is presented. A major modification in 1974 to the MAS 2-8, that of a control subsystem to automate the data-taking operation, is the prime focus. The digital control unit automatically changes all system parameters except FM rate and records the return signal on paper tape. The overall system operation and a detailed discussion of the design and operation of the digital control unit are presented.

  2. 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)

  3. 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

  4. A new approach to the silica gel surface : characterization of different surface regions by 29Si magic angle spinning NMR relaxation parameters and consequences for quantification of silica gels by NMR: characterization of different surface regions by silicon-29 magic angle spinning NMR relaxation parameters and consequences for quantification of silica gels by NMR

    NARCIS (Netherlands)

    Pfleiderer, B.; Albert, K.; Bayer, E.; Ven, van de L.J.M.; Haan, de J.W.; Cramers, C.A.M.G.

    1990-01-01

    Native and some monofunctionally derivatized silica gels have been investigated by 29Si CP MAS NMR spectroscopy with pulse and with cross-polarization (CP) excitation. Contact time variation experiments for some native materials yield results for the siloxane (Q4)g roups which cannot be described

  5. TG/DTG, FT-ICR Mass Spectrometry, and NMR Spectroscopy Study of Heavy Fuel Oil

    KAUST Repository

    Elbaz, Ayman M.; Abdul Jameel, Abdul Gani; Hourani, Nadim; Emwas, Abdul-Hamid M.; Sarathy, Mani; Roberts, William L.

    2015-01-01

    infusion atmospheric pressure chemical ionization Fourier transform ion cyclotron resonance mass spectrometry (APCI-FTICR MS), high resolution 1H nuclear magnetic resonance (NMR), 13C NMR, and two-dimensional heteronuclear multiple bond correlation (HMBC

  6. Communication: Localized molecular orbital analysis of the effect of electron correlation on the anomalous isotope effect in the NMR spin-spin coupling constant in methane

    Energy Technology Data Exchange (ETDEWEB)

    Zarycz, M. Natalia C., E-mail: mnzarycz@gmail.com; Provasi, Patricio F., E-mail: patricio@unne.edu.ar [Department of Physics, University of Northeastern - CONICET, Av. Libertad 5500, Corrientes W3404AAS (Argentina); Sauer, Stephan P. A., E-mail: sauer@kiku.dk [Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø (Denmark)

    2014-10-21

    We discuss the effect of electron correlation on the unexpected differential sensitivity (UDS) in the {sup 1}J(C–H) coupling constant of CH{sub 4} using a decomposition into contributions from localized molecular orbitals and compare with the {sup 1}J(N–H) coupling constant in NH{sub 3}. In particular, we discuss the well known fact that uncorrelated coupled Hartree-Fock (CHF) calculations are not able to reproduce the UDS in methane. For this purpose we have implemented for the first time a localized molecular orbital analysis for the second order polarization propagator approximation with coupled cluster singles and doubles amplitudes—SOPPA(CCSD) in the DALTON program. Comparing the changes in the localized orbital contributions at the correlated SOPPA and SOPPA(CCSD) levels and at the uncorrelated CHF level, we find that the latter overestimates the effect of stretching the bond between the coupled atoms on the contribution to the coupling from the localized bonding orbital between these atoms. This disturbs the subtle balance between the molecular orbital contributions, which lead to the UDS in methane.

  7. Authenticity study of Phyllanthus species by NMR and FT-IR techniques coupled with chemometric methods

    International Nuclear Information System (INIS)

    Santos, Maiara S.; Pereira-Filho, Edenir R.; Ferreira, Antonio G.; Boffo, Elisangela F.; Figueira, Glyn M.

    2012-01-01

    The importance of medicinal plants and their use in industrial applications is increasing worldwide, especially in Brazil. Phyllanthus species, popularly known as 'quebra-pedras' in Brazil, are used in folk medicine for treating urinary infections and renal calculus. This paper reports an authenticity study, based on herbal drugs from Phyllanthus species, involving commercial and authentic samples using spectroscopic techniques: FT-IR, 1 H HR-MAS NMR and 1 H NMR in solution, combined with chemometric analysis. The spectroscopic techniques evaluated, coupled with chemometric methods, have great potential in the investigation of complex matrices. Furthermore, several metabolites were identified by the NMR techniques. (author)

  8. Authenticity study of Phyllanthus species by NMR and FT-IR Techniques coupled with chemometric methods

    Directory of Open Access Journals (Sweden)

    Maiara S. Santos

    2012-01-01

    Full Text Available The importance of medicinal plants and their use in industrial applications is increasing worldwide, especially in Brazil. Phyllanthus species, popularly known as "quebra-pedras" in Brazil, are used in folk medicine for treating urinary infections and renal calculus. This paper reports an authenticity study, based on herbal drugs from Phyllanthus species, involving commercial and authentic samples using spectroscopic techniques: FT-IR, ¹H HR-MAS NMR and ¹H NMR in solution, combined with chemometric analysis. The spectroscopic techniques evaluated, coupled with chemometric methods, have great potential in the investigation of complex matrices. Furthermore, several metabolites were identified by the NMR techniques.

  9. Fluorine dynamics in BaF2 superionic conductors investigated by NMR

    OpenAIRE

    Gumann, Patryk

    2008-01-01

    In this work the dynamics of fluorine in solid-state electrolytes having BaF2-structure was investigated using three different NMR-methods: field cycling relaxometry, lineshape analysis, and static field gradient NMR. For this purpose a pure BaF2 crystal, as well as crystals doped with trivalent impurities (LaF3), were studied as a function of temperature. The main goal of this investigation was to utilize the structure information provided by neutron scattering and MAS NMR data in order to s...

  10. Authenticity study of Phyllanthus species by NMR and FT-IR techniques coupled with chemometric methods

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Maiara S.; Pereira-Filho, Edenir R.; Ferreira, Antonio G. [Universidade Federal de Sao Carlos (UFSCAR), SP (Brazil). Dept. de Quimica; Boffo, Elisangela F. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica; Figueira, Glyn M., E-mail: maiarassantos@yahoo.com.br [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Centro Pluridisciplinar de Pesquisas Quimicas, Biologicas e Agricolas

    2012-07-01

    The importance of medicinal plants and their use in industrial applications is increasing worldwide, especially in Brazil. Phyllanthus species, popularly known as 'quebra-pedras' in Brazil, are used in folk medicine for treating urinary infections and renal calculus. This paper reports an authenticity study, based on herbal drugs from Phyllanthus species, involving commercial and authentic samples using spectroscopic techniques: FT-IR, {sup 1}H HR-MAS NMR and {sup 1}H NMR in solution, combined with chemometric analysis. The spectroscopic techniques evaluated, coupled with chemometric methods, have great potential in the investigation of complex matrices. Furthermore, several metabolites were identified by the NMR techniques. (author)

  11. Authenticity study of Phyllanthus species by NMR and FT-IR techniques coupled with chemometric methods

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Maiara S.; Pereira-Filho, Edenir R.; Ferreira, Antonio G. [Universidade Federal de Sao Carlos (UFSCAR), SP (Brazil). Dept. de Quimica; Boffo, Elisangela F. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica; Figueira, Glyn M., E-mail: maiarassantos@yahoo.com.br [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Centro Pluridisciplinar de Pesquisas Quimicas, Biologicas e Agricolas

    2012-07-01

    The importance of medicinal plants and their use in industrial applications is increasing worldwide, especially in Brazil. Phyllanthus species, popularly known as 'quebra-pedras' in Brazil, are used in folk medicine for treating urinary infections and renal calculus. This paper reports an authenticity study, based on herbal drugs from Phyllanthus species, involving commercial and authentic samples using spectroscopic techniques: FT-IR, {sup 1}H HR-MAS NMR and {sup 1}H NMR in solution, combined with chemometric analysis. The spectroscopic techniques evaluated, coupled with chemometric methods, have great potential in the investigation of complex matrices. Furthermore, several metabolites were identified by the NMR techniques. (author)

  12. Sensitivity improvement for correlations involving arginine side-chain N{epsilon}/H{epsilon} resonances in multi-dimensional NMR experiments using broadband {sup 15}N 180{sup o} pulses

    Energy Technology Data Exchange (ETDEWEB)

    Iwahara, Junji; Clore, G. Marius [National Institutes of Health, Laboratory of Chemical Physics, Building 5, National Institute of Diabetes and Digestive and Kidney Disease (United States)], E-mail: mariusc@intra.niddk.nih.gov

    2006-12-15

    Due to practical limitations in available {sup 15}N rf field strength, imperfections in {sup 15}N 180{sup o} pulses arising from off-resonance effects can result in significant sensitivity loss, even if the chemical shift offset is relatively small. Indeed, in multi-dimensional NMR experiments optimized for protein backbone amide groups, cross-peaks arising from the Arg guanidino {sup 15}N{epsilon} ({approx}85 ppm) are highly attenuated by the presence of multiple INEPT transfer steps. To improve the sensitivity for correlations involving Arg N{epsilon}-H{epsilon} groups, we have incorporated {sup 15}N broadband 180 deg. pulses into 3D {sup 15}N-separated NOE-HSQC and HNCACB experiments. Two {sup 15}N-WURST pulses incorporated at the INEPT transfer steps of the 3D {sup 15}N-separated NOE-HSQC pulse sequence resulted in a {approx}1.5-fold increase in sensitivity for the Arg N{epsilon}-H{epsilon} signals at 800 MHz. For the 3D HNCACB experiment, five {sup 15}N Abramovich-Vega pulses were incorporated for broadband inversion and refocusing, and the sensitivity of Arg{sup 1}H{epsilon}-{sup 15}N{epsilon}-{sup 13}C{gamma}/{sup 13}C{delta} correlation peaks was enhanced by a factor of {approx}1.7 at 500 MHz. These experiments eliminate the necessity for additional experiments to assign Arg {sup 1}H{epsilon} and {sup 15}N{epsilon} resonances. In addition, the increased sensitivity afforded for the detection of NOE cross-peaks involving correlations with the {sup 15}N{epsilon}/{sup 1}H{epsilon} of Arg in 3D {sup 15}N-separated NOE experiments should prove to be very useful for structural analysis of interactions involving Arg side-chains.

  13. 3D 14N/1H Double Quantum/1H Single Quantum Correlation Solid-State NMR for Probing Parallel and Anti-Parallel Beta-Sheet Arrangement of Oligo-Peptides at Natural Abundance.

    Science.gov (United States)

    Hong, You-Lee; Asakura, Tetsuo; Nishiyama, Yusuke

    2018-05-08

    β-sheet structure of oligo- and poly-peptides can be formed in anti-parallel (AP)- and parallel (P)-structure, which is the important feature to understand the structures. In principle, P- and AP-β-sheet structures can be identified by the presence (AP) and absence (P) of the interstrand 1HNH/1HNH correlations on a diagonal in 2D 1H double quantum (DQ)/1H single quantum (SQ) spectrum due to the different interstrand 1HNH/1HNH distances between these two arrangements. However, the 1HNH/1HNH peaks overlap to the 1HNH3+/1HNH3+ peaks, which always give cross peaks regardless of the β-sheet arrangement. The 1HNH3+/1HNH3+ peaks disturb the observation of the presence/absence of 1HNH/1HNH correlations and the assignment of 1HNH and 1HNH3+ is not always available. Here, 3D 14N/1H DQ/1H SQ correlation solid-state NMR experiments at fast magic angle spinning (70 kHz) are introduced to distinguish AP and P β-sheet structure. The 14N dimension allows the separate observation of 1HNH/1HNH peaks from 1HNH3+/1HNH3+ peaks with clear assignment of 1HNH and 1HNH3+. In addition, the high natural abundance of 1H and 14N enables 3D 14N/1H DQ/1H SQ experiments of oligo-alanines (Ala3-6) in four hours without any isotope labelling. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. The evolution of the MasAgro hubs

    NARCIS (Netherlands)

    Camacho-Villa, Tania Carolina; Almekinders, Conny; Hellin, Jon; Martinez-Cruz, Tania Eulalia; Rendon-Medel, Roberto; Guevara-Hernández, Francisco; Beuchelt, Tina D.; Govaerts, Bram

    2016-01-01

    Purpose: Little is known about effective ways to operationalize agricultural innovation processes. We use the MasAgro program in Mexico (which aims to increase maize and wheat productivity, profitability and sustainability), and the experiences of middle level ‘hub managers’, to understand how

  15. Angiotensin type 2 receptor (AT2R) and receptor Mas

    DEFF Research Database (Denmark)

    Villela, Daniel; Leonhardt, Julia; Patel, Neal

    2015-01-01

    The angiotensin type 2 receptor (AT2R) and the receptor Mas are components of the protective arms of the renin-angiotensin system (RAS), i.e. they both mediate tissue protective and regenerative actions. The spectrum of actions of these two receptors and their signalling mechanisms display striki...

  16. 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

  17. 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

  18. Catalyst surface characterized by high magnetic field NMR; Kojiba NMR ni yoru shokubai hyomen no kansatsu

    Energy Technology Data Exchange (ETDEWEB)

    Sato, S. [Chiba University, Chiba (Japan). Faculty of Engineering

    1997-08-01

    This paper introduces studies performed by the authors on observation of surface of solid catalysts by means of solid NMR measurement using the high-speed MAS technology which uses a high magnetic field device. In the studies, a device with 14.1T (resonant frequency of proton at 600 MHz) was used to conduct CP-MAS NMR measurement on {sup 29}Si to identify bonding of silica carrier in a fixed aluminum chloride catalyst. As a result, it was verified that the surface structure of aluminum chloride species deposited on the silica carrier turns to a structure in which AlCl2 species of a monomeric substance is bonded with a surface hydroxyl group and fixed in four- or five-orientation. When adjusted at low temperatures, an Al2Cl5 structure is formed, which is fixed as a dimeric substance with AlCl3 oriented in the AlCl2 species. It is conceived that the Al2Cl5 species has higher electrophilicity than the AlCl2 species as a result of AlCl3 oriented in AlCl2, whereas the hydroxyl group on the silica surface oriented with the Al2Cl5 species dissociates, discharging protons, thus showing strong acidity. 18 refs., 8 figs., 2 tabs.

  19. Dynamics and interactions of ibuprofen in cyclodextrin nanosponges by solid-state NMR spectroscopy

    Directory of Open Access Journals (Sweden)

    Monica Ferro

    2017-01-01

    Full Text Available Two different formulations of cyclodextrin nanosponges (CDNS, obtained by polycondensation of β-cyclodextrin with ethylenediaminetetraacetic acid dianhydride (EDTAn, were treated with aqueous solutions of ibuprofen sodium salt (IbuNa affording hydrogels that, after lyophilisation, gave two solid CDNS-drug formulations. 1H fast MAS NMR and 13C CP-MAS NMR spectra showed that IbuNa was converted in situ into its acidic and dimeric form (IbuH after freeze-drying. 13C CP-MAS NMR spectra also indicated that the structure of the nanosponge did not undergo changes upon drug loading compared to the unloaded system. However, the 13C NMR spectra collected under variable contact time cross-polarization (VCT-CP conditions showed that the polymeric scaffold CDNS changed significantly its dynamic regime on passing from the empty CDNS to the drug-loaded CDNS, thus showing that the drug encapsulation can be seen as the formation of a real supramolecular aggregate rather than a conglomerate of two solid components. Finally, the structural features obtained from the different solid-state NMR approaches reported matched the information from powder X-ray diffraction profiles.

  20. Evaluation of group electronegativities and hardness (softness) of group 14 elements and containing functional groups through density functional theory and correlation with NMR spectra data

    International Nuclear Information System (INIS)

    Vivas-Reyes, R.; Aria, A.

    2008-01-01

    Quantum Chemical calculations for group 14 elements of Periodic Table (C, Si, Ge, Sn, Pb) and their functional groups have been carried out using Density Functional Theory (DFT) based reactivity descriptors such as group electronegativities, hardness and softness. DFT calculations were performed for a large series of tetra coordinated Sn compounds of the CH 3 SnRR'X type, where X is a halogen and R and R' are alkyl, halogenated alkyl, alkoxy, or alkyl thio groups. The results were interpreted in terms of calculated electronegativity and hardness of the SnRR'X groups, applying a methodology previously developed by Geerlings and coworkers (J. Phys. Chem. 1993, 97, 1826). These calculations allowed to see the regularities concerning the influence of the nature of organic groups RR' and inorganic group X on electronegativities and hardness of the SnRR'X groups; in this case, it was found a very good correlation between the electronegativity of the fragment and experimental 119 Sn chemical shifts, a property that sensitively reflects the change in the valence electronic structure of molecules. This work was complemented with the study of some compounds of the EX and ER types, where E= C, Si, Ge, Sn and R= CH 3 , H, which was performed to study the influence that the central atom has on the electronegativity and hardness of molecules, or whether these properties are mainly affected for the type of ligand bound to the central atom. All these calculations were performed using the B3PW91 functional together with the 6-3 1 1 + + G basis set level for H, C, Si, Ge, F, Cl and Br atoms and the 3-21G for Sn and I atoms. (author)

  1. Evaluation of group electronegativities and hardness (softness) of group 14 elements and containing functional groups through density functional theory and correlation with NMR spectra data

    Energy Technology Data Exchange (ETDEWEB)

    Vivas-Reyes, R.; Aria, A. [Universidad de Cartagena, Cartagena (Colombia). Facultad de Ciencias Naturales y Exactas. Grupo de Quimica Cuantica y Computacional]. E-mail: rvivasr@unicartagena.edu.co

    2008-07-01

    Quantum Chemical calculations for group 14 elements of Periodic Table (C, Si, Ge, Sn, Pb) and their functional groups have been carried out using Density Functional Theory (DFT) based reactivity descriptors such as group electronegativities, hardness and softness. DFT calculations were performed for a large series of tetra coordinated Sn compounds of the CH{sub 3}SnRR'X type, where X is a halogen and R and R' are alkyl, halogenated alkyl, alkoxy, or alkyl thio groups. The results were interpreted in terms of calculated electronegativity and hardness of the SnRR'X groups, applying a methodology previously developed by Geerlings and coworkers (J. Phys. Chem. 1993, 97, 1826). These calculations allowed to see the regularities concerning the influence of the nature of organic groups RR' and inorganic group X on electronegativities and hardness of the SnRR'X groups; in this case, it was found a very good correlation between the electronegativity of the fragment and experimental {sup 119}Sn chemical shifts, a property that sensitively reflects the change in the valence electronic structure of molecules. This work was complemented with the study of some compounds of the EX and ER types, where E= C, Si, Ge, Sn and R= CH{sub 3}, H, which was performed to study the influence that the central atom has on the electronegativity and hardness of molecules, or whether these properties are mainly affected for the type of ligand bound to the central atom. All these calculations were performed using the B3PW91 functional together with the 6-3 1 1 + + G basis set level for H, C, Si, Ge, F, Cl and Br atoms and the 3-21G for Sn and I atoms. (author)

  2. 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.

  3. NMR characterization of simulated Hanford low-activity waste glasses and its use in understanding waste form chemical durability

    International Nuclear Information System (INIS)

    Darab, J.G.; Linehan, J.C.; McGrail, B.P.

    1999-01-01

    Magic Angle Spinning Nuclear Magnetic Resonance (MAS-NMR) spectroscopy has been used to characterize the structural and chemical environments of B, Al, and Si in model Hanford low-activity waste glasses. The average 29 Si NMR peak position was found to systematically change with changing glass composition and structure. From an understanding of the structural roles of Al and B obtained from MAS-NMR experiments, the authors first developed a model that reliably predicts the distribution of structural units and the average 29 Si chemical shift value, δ, based purely on glass composition. A product consistency test (PCT) was used to determine the normalized elemental release (NL) from the prepared glasses. Comparison of the NMR and PCT data obtained from sodium boro-aluminosilicate glasses indicates that a rudimentary exponential relationship exists between the 29 Si chemical shift value, and the boron NL value

  4. Multinuclear (27Al, 29Si, 47,49Ti) solid-state NMR of titanium substituted zeolite USY.

    Science.gov (United States)

    Ganapathy, S; Gore, K U; Kumar, Rajiv; Amoureux, Jean-Paul

    2003-01-01

    Multinuclear solid-state NMR spectroscopy, employing 29Si MAS,27Al MAS/3Q-MAS and (47,49)Ti wide-line experiments, has been used for the structural characterization of titanium substituted ultra-stable zeolite Y (Ti-USY). 27Al MAS experiments show the presence of aluminum in four (Al(IV)), five (Al(V)), and six (Al(VI)) coordination, whereas the multiplicity within Al(IV) and Al(VI) is revealed by 27Al 3Q-MAS experiments. Two different tetrahedral and octahedral Al environments are resolved and their isotropic chemical shifts (delta(CS)) and second-order quadrupole interaction parameters (P(Q)) have been determined by a graphical analysis of the 3Q-MAS spectra. The emergence of signal with higher intensity at -101 ppm in the 29Si MAS spectrum of Ti-USY samples indicates the possible occurrence of Q4(3Si,1Ti) type silicon environments due to titanium substitution in the faujasite framework. High-field (11.74T) operation, using a probehead specially designed to handle a large sample volume, has enabled the acquisition of 47,49Ti static spectra and identification of the titanium environment in the zeolite. The chemical shielding and electric field gradient tensors for the titanium environment in the zeolite have been determined by a computer simulation of the quadrupolar broadened static 47,49Ti NMR spectra.

  5. ERP sistēmas ieviešana

    OpenAIRE

    Proskurins, Aleksandrs

    2008-01-01

    Šajā darbā tika apskatīta informācijas sistēmu klasifikācija, uzņēmuma resursu plānošanas sistēmas (ERP) definīcija un tās vieta IS klasifikācijā. Tika apskatīti ERP sistēmu ieviešanas teorētiskie aspekti, izstrādes un pielāgošanas specifika, kā arī tika izanalizēti vairāki ERP sistēmas ieviešanas projekti Latvijas uzņēmumos.

  6. Ab initio random structure searching of organic molecular solids: assessment and validation against experimental data† †Electronic supplementary information (ESI) available: Results of similarity analysis between the 11 structures of lowest energy obtained in the AIRSS calculations and the reported structures of form III and form IV of m-ABA; unit cell parameters and volumes for all structures considered; comparison of 2θ values derived from the unit cell parameters of different structural models representing form III of m-ABA; Le Bail fitting of the experimental powder XRD pattern of form IV of m-ABA recorded at 70 K using, as the initial structural model, the reported crystal structure following geometry optimization; table of calculated (GIPAW) absolute isotropic NMR shieldings; simulated powder XRD data for the considered structures after precise geometry optimization; experimental 1H MAS NMR spectra of forms III and IV. (pdf) The calculated and experimental data for this study are provided as a supporting dataset from WRAP, the Warwick Research Archive Portal at http://wrap.warwick.ac.uk/91884. See DOI: 10.1039/c7cp04186a

    Science.gov (United States)

    Zilka, Miri; Dudenko, Dmytro V.; Hughes, Colan E.; Williams, P. Andrew; Sturniolo, Simone; Franks, W. Trent; Pickard, Chris J.

    2017-01-01

    This paper explores the capability of using the DFT-D ab initio random structure searching (AIRSS) method to generate crystal structures of organic molecular materials, focusing on a system (m-aminobenzoic acid; m-ABA) that is known from experimental studies to exhibit abundant polymorphism. Within the structural constraints selected for the AIRSS calculations (specifically, centrosymmetric structures with Z = 4 for zwitterionic m-ABA molecules), the method is shown to successfully generate the two known polymorphs of m-ABA (form III and form IV) that have these structural features. We highlight various issues that are encountered in comparing crystal structures generated by AIRSS to experimental powder X-ray diffraction (XRD) data and solid-state magic-angle spinning (MAS) NMR data, demonstrating successful fitting for some of the lowest energy structures from the AIRSS calculations against experimental low-temperature powder XRD data for known polymorphs of m-ABA, and showing that comparison of computed and experimental solid-state NMR parameters allows different hydrogen-bonding motifs to be discriminated. PMID:28944393

  7. 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

  8. 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

  9. 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.

  10. 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

  11. PROPAGANDA POLITIK PARTAI GERINDRA DALAM GAME MAS GARUDA PADA PEMILU 2014 (Analisis Deskriptif Game Online Mas Garuda

    Directory of Open Access Journals (Sweden)

    Angga Satrya Putra

    2016-03-01

    Full Text Available The purpose of this study was to determine how the meaning of the look and content of the online game “Garuda Mas”. This game contains aspects of politically charged designations so that it can become a propaganda technique. The subject of this study is the game “Garuda Mas” which has been input on social media Facebook.Methods of data collection using documentary and literature. Data analysis using descriptive techniques. Data validity checking techniques using triangulation source.The results showed that the game “MAS GARUDA” can form the perspective of the players against Mas Garuda as a superhero figure hopes the Indonesian people who are able to overcome all the problems that exist in Indonesia. This game is a form of creative campaigns using propaganda techniques inserted in the game that has the power to change the mindset of every player. Change of mindset occurs because the player did not have an opportunity to think critically on aspects marking contained in the game. By indirectly the players will feel the emotional of this game and assume characterizations “Garuda Mas” in this game is a truth that can be believed.Keywords: Descriptive, Online Games, Mas Garuda, Partai Gerindra

  12. Biomolecular solid state NMR with magic-angle spinning at 25K.

    Science.gov (United States)

    Thurber, Kent R; Tycko, Robert

    2008-12-01

    A magic-angle spinning (MAS) probe has been constructed which allows the sample to be cooled with helium, while the MAS bearing and drive gases are nitrogen. The sample can be cooled to 25K using roughly 3 L/h of liquid helium, while the 4-mm diameter rotor spins at 6.7 kHz with good stability (+/-5 Hz) for many hours. Proton decoupling fields up to at least 130 kHz can be applied. This helium-cooled MAS probe enables a variety of one-dimensional and two-dimensional NMR experiments on biomolecular solids and other materials at low temperatures, with signal-to-noise proportional to 1/T. We show examples of low-temperature (13)C NMR data for two biomolecular samples, namely the peptide Abeta(14-23) in the form of amyloid fibrils and the protein HP35 in frozen glycerol/water solution. Issues related to temperature calibration, spin-lattice relaxation at low temperatures, paramagnetic doping of frozen solutions, and (13)C MAS NMR linewidths are discussed.

  13. Antioxidant capacity of cornelian cherry (Cornus mas L.) - comparison between permanganate reducing antioxidant capacity and other antioxidant methods.

    Science.gov (United States)

    Popović, Boris M; Stajner, Dubravka; Slavko, Kevrešan; Sandra, Bijelić

    2012-09-15

    Ethanol extracts (80% in water) of 10 cornelian cherry (Cornus mas L.) genotypes were studied for antioxidant properties, using methods including DPPH(), ()NO, O(2)(-) and ()OH antiradical powers, FRAP, total phenolic and anthocyanin content (TPC and ACC) and also one relatively new, permanganate method (permanganate reducing antioxidant capacity-PRAC). Lipid peroxidation (LP) was also determined as an indicator of oxidative stress. The data from different procedures were compared and analysed by multivariate techniques (correlation matrix calculation and principal component analysis (PCA)). Significant positive correlations were obtained between TPC, ACC and DPPH(), ()NO, O(2)(-), and ()OH antiradical powers, and also between PRAC and TPC, ACC and FRAP. PCA found two major clusters of cornelian cherry, based on antiradical power, FRAP and PRAC and also on chemical composition. Chemometric evaluation showed close interdependence between PRAC method and FRAP and ACC. There was a huge variation between C. mas genotypes in terms of antioxidant activity. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. 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

  15. Characterization of lithium coordination sites with magic-angle spinning NMR

    Science.gov (United States)

    Haimovich, A.; Goldbourt, A.

    2015-05-01

    Lithium, in the form of lithium carbonate, is one of the most common drugs for bipolar disorder. Lithium is also considered to have an effect on many other cellular processes hence it possesses additional therapeutic as well as side effects. In order to quantitatively characterize the binding mode of lithium, it is required to identify the interacting species and measure their distances from the metal center. Here we use magic-angle spinning (MAS) solid-state NMR to study the binding site of lithium in complex with glycine and water (LiGlyW). Such a compound is a good enzyme mimetic since lithium is four-coordinated to one water molecule and three carboxylic groups. Distance measurements to carbons are performed using a 2D transferred echo double resonance (TEDOR) MAS solid-state NMR experiment, and water binding is probed by heteronuclear high-resolution proton-lithium and proton-carbon correlation (wPMLG-HETCOR) experiments. Both HETCOR experiments separate the main complex from impurities and non-specifically bound lithium species, demonstrating the sensitivity of the method to probe the species in the binding site. Optimizations of the TEDOR pulse scheme in the case of a quadrupolar nucleus with a small quadrupole coupling constant show that it is most efficient when pulses are positioned on the spin-1/2 (carbon-13) nucleus. Since the intensity of the TEDOR signal is not normalized, careful data analysis that considers both intensity and dipolar oscillations has to be performed. Nevertheless we show that accurate distances can be extracted for both carbons of the bound glycine and that these distances are consistent with the X-ray data and with lithium in a tetrahedral environment. The lithium environment in the complex is very similar to the binding site in inositol monophosphatase, an enzyme associated with bipolar disorder and the putative target for lithium therapy. A 2D TEDOR experiment applied to the bacterial SuhB gene product of this enzyme was designed

  16. Water speciation in sodium silicate glasses (quenched melts): A comprehensive NMR study

    Science.gov (United States)

    Xue, X.; Kanzaki, M.; Eguchi, J.

    2012-12-01

    Dissolution mechanism of water is an important factor governing how the dissolved water affects the physical and thermodynamic properties of silicate melts and glasses. Our previous studies have demonstrated that 1H MAS NMR in combination with 29Si-1H and 27Al-1H double-resonance NMR experiments is an effective approach for unambiguously differentiating and quantifying different water species in quenched silicate melts (glasses). Several contrasting dissolution mechanisms have been revealed depending on the melt composition: for relatively polymerized melts, the formation of SiOH/AlOH species (plus molecular H2O) and depolymerization of the network structure dominate; whereas for depolymerized Ca-Mg silicate melts, free OH (e.g. MgOH) become increasingly important (cf. [1]). The proportion of free OH species has been shown to decrease with both increasing melt polymerization (silica content) and decreasing field strength of the network modifying cations (from Mg to Ca). Our previous 1H and 29Si MAS NMR results for hydrous Na silicate glasses of limited compositions (Na2Si4O9 and Na2Si2O5) were consistent with negligible free OH (NaOH) species and depolymerizing effect of water dissolution [2]. On the other hand, there were also other studies that proposed the presence of significant NaOH species in hydrous glasses near the Na2Si2O5 composition. The purpose of this study is apply the approach of combined 1H MAS NMR and double-resonance (29Si-1H and 23Na-1H) NMR to gain unambiguous evidence for the OH speciation in Na silicate glasses (melts) as a function of composition. Hydrous Na silicate glasses containing mostly ≤ 1 wt% H2O for a range of Na/Si ratios from 0.33 to 1.33 have been synthesized by rapidly quenching melts either at 0.2 GPa using an internally heated gas pressure vessel or at 1 GPa using a piston cylinder high-pressure apparatus. NMR spectra have been acquired using a 9.4 T Varian Unity-Inova spectrometer. The 29Si and 1H chemical shifts are

  17. Two-dimensional NMR spectroscopy. Applications for chemists and biochemists

    International Nuclear Information System (INIS)

    Croasmun, W.R.; Carlson, R.M.K.

    1987-01-01

    Two-dimensional nuclear magnetic resonance spectroscopy (2-D NMR) has become a very powerful class of experiments (in the hands of an adept scientist) with broad adaptability to new situations. It is the product of a happy marriage between modern pulse FT-NMR technology, with its large memory and high-speed computers, and the physicists and chemists who love to manipulate spin systems. Basic 2-D experiments are now a standard capability of modern NMR spectrometers, and this timely book intends to make 2-D NMR users of those who are familiar with normal 1-D NMR. The 2-D NMR goal is correlation of the lines of the observed NMR spectrum with other properties of the system. This book deals with applications to high-resolution spectrum analysis, utilizing either coupling between the NMR-active nuclei or chemical exchange to perform the correlation. The coupling can be scalar (through bonds) or direct through space (within 5 A). The coupling may be homonuclear (between like nuclei) or heteronuclear

  18. Hexagonal ice in pure water and biological NMR samples

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Thomas; Gath, Julia; Hunkeler, Andreas; Ernst, Matthias, E-mail: maer@ethz.ch [ETH Zurich, Physical Chemistry (Switzerland); Böckmann, Anja, E-mail: a.bockmann@ibcp.fr [UMR 5086 CNRS, Université de Lyon 1, Institut de Biologie et Chimie des Protéines (France); Meier, Beat H., E-mail: beme@ethz.ch [ETH Zurich, Physical Chemistry (Switzerland)

    2017-01-15

    Ice, in addition to “liquid” water and protein, is an important component of protein samples for NMR spectroscopy at subfreezing temperatures but it has rarely been observed spectroscopically in this context. We characterize its spectroscopic behavior in the temperature range from 100 to 273 K, and find that it behaves like pure water ice. The interference of magic-angle spinning (MAS) as well as rf multiple-pulse sequences with Bjerrum-defect motion greatly influences the ice spectra.

  19. Characterization of zeolites by magic-angle-spinning NMR

    International Nuclear Information System (INIS)

    Brunner, E.; Ernst, H.; Freude, D.; Hunger, M.; Pfeifer, H.

    1988-01-01

    Magic-angle-spinning nuclear magnetic resonance (MAS NMR) has been used to study structure defects in TPA/ZSM-5, the dealumination process caused by hydrothermal treatment and acid leaching of zeolites, the influence of Lewis sites upon water as a probe molecule, the boron incorporation into the ZSM-5 framework, and the acid sites and structure defects in SAPO-5. The nuclei under study are 1 H, 11 B, 27 Al, 29 Si, and 31 P. 24 refs.; 7 figs.; 1 table

  20. Development of 19F-NMR chemical shift detection of DNA B-Z equilibrium using 19F-NMR.

    Science.gov (United States)

    Nakamura, S; Yang, H; Hirata, C; Kersaudy, F; Fujimoto, K

    2017-06-28

    Various DNA conformational changes are in correlation with biological events. In particular, DNA B-Z equilibrium showed a high correlation with translation and transcription. In this study, we developed a DNA probe containing 5-trifluoromethylcytidine or 5-trifluoromethylthymidine to detect DNA B-Z equilibrium using 19 F-NMR. Its probe enabled the quantitative detection of B-, Z-, and ss-DNA based on 19 F-NMR chemical shift change.

  1. What drives cross-border M&As in commercial banking?

    NARCIS (Netherlands)

    Galamhussen, Mohamed; Hennart, Jean-Francois; Pinheiro, Carlos Manuel

    2016-01-01

    Using a gravity model, we analyze the determinants of the probability that commercial banks in 89 acquiring countries and 118 target countries will undertake M&As over a 30-year period (1981–2010) and of the value of these M&As. We find that the value of cross-border M&As increases with the size of

  2. Applications of solid-state Nuclear Magnetic Resonance (NMR) in studies of Portland cements-based materials

    DEFF Research Database (Denmark)

    Skibsted, Jørgen; Andersen, Morten Daugaard; Jakobsen, Hans Jørgen

    2007-01-01

    Solid-state NMR spectroscopy represents an important research tool in the characterization of a range of structural properties for cement-based materials. Different approaches of the technique can be used to obtain information on hydration kinetics, mobile and bound water, porosity, and local...... atomic structures. After a short introduction to these NMR techniques, it is exemplified how magic-angle spinning (MAS) NMR can provide quantitative and structural information about specific phases in anhydrous and hydrated Portland cements with main emphasis on the incorporation of Al3+ ions...

  3. 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.)

  4. The importance of including local correlation times in the calculation of inter-proton distances from NMR measurements: ignoring local correlation times leads to significant errors in the conformational analysis of the Glc alpha1-2Glc alpha linkage by NMR spectroscopy.

    Science.gov (United States)

    Mackeen, Mukram; Almond, Andrew; Cumpstey, Ian; Enis, Seth C; Kupce, Eriks; Butters, Terry D; Fairbanks, Antony J; Dwek, Raymond A; Wormald, Mark R

    2006-06-07

    The experimental determination of oligosaccharide conformations has traditionally used cross-linkage 1H-1H NOE/ROEs. As relatively few NOEs are observed, to provide sufficient conformational constraints this method relies on: accurate quantification of NOE intensities (positive constraints); analysis of absent NOEs (negative constraints); and hence calculation of inter-proton distances using the two-spin approximation. We have compared the results obtained by using 1H 2D NOESY, ROESY and T-ROESY experiments at 500 and 700 MHz to determine the conformation of the terminal Glc alpha1-2Glc alpha linkage in a dodecasaccharide and a related tetrasaccharide. For the tetrasaccharide, the NOESY and ROESY spectra produced the same qualitative pattern of linkage cross-peaks but the quantitative pattern, the relative peak intensities, was different. For the dodecasaccharide, the NOESY and ROESY spectra at 500 MHz produced a different qualitative pattern of linkage cross-peaks, with fewer peaks in the NOESY spectrum. At 700 MHz, the NOESY and ROESY spectra of the dodecasaccharide produced the same qualitative pattern of peaks, but again the relative peak intensities were different. These differences are due to very significant differences in the local correlation times for different proton pairs across this glycosidic linkage. The local correlation time for each proton pair was measured using the ratio of the NOESY and T-ROESY cross-relaxation rates, leaving the NOESY and ROESY as independent data sets for calculating the inter-proton distances. The inter-proton distances calculated including the effects of differences in local correlation times give much more consistent results.

  5. 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

  6. Microscopic structural analysis of fractured silk fibers from Bombyx mori and Samia cynthia ricini using 13C CP/MAS NMR with a 1 mm microcoil MAS NMR probehead

    KAUST Repository

    Yamauchi, Kazuo; Yamasaki, Shizuo; Takahashi, Rui; Asakura, Tetsuo

    2010-01-01

    Conformational changes have been studied in silk fibers from the domestic silkworm Bombyx mori and a wild silkworm Samia cynthia ricini as a result of fractured by stretching. About 300 samples consisting of only the fractured regions of [1-13C

  7. 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.)

  8. Proton Environments in Biomimetic Calcium Phosphates Formed from Mesoporous Bioactive CaO-SiO2-P2O5 Glasses in Vitro: Insights from Solid-State NMR.

    Science.gov (United States)

    Mathew, Renny; Turdean-Ionescu, Claudia; Yu, Yang; Stevensson, Baltzar; Izquierdo-Barba, Isabel; García, Ana; Arcos, Daniel; Vallet-Regí, María; Edén, Mattias

    2017-06-22

    When exposed to body fluids, mesoporous bioactive glasses (MBGs) of the CaO-SiO 2 -P 2 O 5 system develop a bone-bonding surface layer that initially consists of amorphous calcium phosphate (ACP), which transforms into hydroxy-carbonate apatite (HCA) with a very similar composition as bone/dentin mineral. Information from various 1 H-based solid-state nuclear magnetic resonance (NMR) experiments was combined to elucidate the evolution of the proton speciations both at the MBG surface and within each ACP/HCA constituent of the biomimetic phosphate layer formed when each of three MBGs with distinct Ca, Si, and P contents was immersed in a simulated body fluid (SBF) for variable periods between 15 min and 30 days. Directly excited magic-angle-spinning (MAS) 1 H NMR spectra mainly reflect the MBG component, whose surface is rich in water and silanol (SiOH) moieties. Double-quantum-single-quantum correlation 1 H NMR experimentation at fast MAS revealed their interatomic proximities. The comparatively minor H species of each ACP and HCA component were probed selectively by heteronuclear 1 H- 31 P NMR experimentation. The initially prevailing ACP phase comprises H 2 O and "nonapatitic" HPO 4 2- /PO 4 3- groups, whereas for prolonged MBG soaking over days, a well-progressed ACP → HCA transformation was evidenced by a dominating O 1 H resonance from HCA. We show that 1 H-detected 1 H → 31 P cross-polarization NMR is markedly more sensitive than utilizing powder X-ray diffraction or 31 P NMR for detecting the onset of HCA formation, notably so for P-bearing (M)BGs. In relation to the long-standing controversy as to whether bone mineral comprises ACP and/or forms via an ACP precursor, we discuss a recently accepted structural core-shell picture of both synthetic and biological HCA, highlighting the close relationship between the disordered surface layer and ACP.

  9. 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.

  10. 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.

  11. NMR studies of chemical structural variation of insoluble organic matter from different carbonaceous chondrite groups

    Science.gov (United States)

    Cody, George D.; Alexander, Conel M. O.'D.

    2005-02-01

    Solid-state 1H and 13C Nuclear Magnetic Resonance (NMR) spectroscopic experiments have been performed on isolated meteoritic Insoluble Organic Matter (IOM) spanning four different carbonaceous chondrite meteorite groups; a CR2 (EET92042), a CI1 (Orgueil), a CM2 (Murchison), and the unique C2 meteorite, Tagish Lake. These solid state NMR experiments reveal considerable variation in bulk organic composition across the different meteorite group's IOM. The fraction of aromatic carbon increases as CR2 meteorite groups. Single pulse (SP) 13C magic angle spinning (MAS) NMR experiments reveal the presence of nanodiamonds with an apparent concentration ranking in the IOM of CR2 IOM of all four meteoritic IOM fractions are highly substituted. Fast spinning SP 1H MAS NMR spectral data combined with other NMR experimental data reveal that the average hydrogen content of sp 3 bonded carbon functional groups is low, requiring a high degree of aliphatic chain branching in each IOM fraction. The variation in chemistry across the meteorite groups is consistent with alteration by low temperature chemical oxidation. It is concluded that such chemistry principally affected the aliphatic moieties whereas the aromatic moieties and nanodiamonds may have been largely unaffected.

  12. 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.

  13. Solid-state 29Si NMR and FTIR analyses of lignin-silica coprecipitates

    DEFF Research Database (Denmark)

    Cabrera Orozco, Yohanna; Cabrera, Andrés; Larsen, Flemming Hofmann

    2016-01-01

    When agricultural residues are processed to ethanol, lignin and silica are some of the main byproducts. Separation of these two products is difficult and the chemical interactions between lignin and silica are not well described. In the present study, the effect of lignin-silica complexing has been...... investigated by characterizing lignin and silica coprecipitates by FTIR and solid state NMR. Silica particles were coprecipitated with three different lignins, three lignin model compounds, and two silanes representing silica-in-lignin model compounds. Comparison of 29Si SP/MAS NMR spectra revealed differences...

  14. Structural Investigations of Portland Cement Components, Hydration, and Effects of Admixtures by Solid-State NMR Spectroscopy

    DEFF Research Database (Denmark)

    Skibsted, Jørgen Bengaard; Andersen, Morten D.; Jakobsen, Hans Jørgen

    2006-01-01

    for the C-S-H phase formed during hydration. It will be demonstrated that Al3+ and flouride guest-ions in the anhydrous and hydrated calcium silicates can be studied in detail by 27Al and 19F MAS NMR, thereby providing information on the local structure and the mechanisms for incorporation of these ions......Solid-state, magic-angle spinning (MAS) NMR spectroscopy represents a valuable tool for structural investigations on the nanoscale of the most important phases in anhydrous and hydrated Portland cements and of various admixtures. This is primarily due to the fact that the method reflects the first......- and second-coordination spheres of the spin nucleus under investigation while it is less sensitive to long-range order. Thus, crystalline as well as amorphous phases can be detected in a quantitative manner by solid-state NMR. In particular the structure of the calcium-silicate-hydrate (C-S-H) phase have...

  15. Exploring abiotic stress on asynchronous protein metabolism in single kernels of wheat studied by NMR spectroscopy and chemometrics

    DEFF Research Database (Denmark)

    Winning, H.; Viereck, N.; Wollenweber, B.

    2009-01-01

    at the vegetative growth stage had little effect on the parameters investigated. For the first time, H-1 HR-MAS NMR spectra of grains taken during grain-filling were analysed by an advanced multiway model. In addition to the results from the chemical protein analysis and the H-1 HR-MAS NMR spectra of single kernels...... was to examine the implications of different drought treatments on the protein fractions in grains of winter wheat using H-1 nuclear magnetic resonance spectroscopy followed by chemometric analysis. Triticum aestivum L. cv. Vinjett was studied in a semi-field experiment and subjected to drought episodes either...... at terminal spikelet, during grain-filling or at both stages. Principal component trajectories of the total protein content and the protein fractions of flour as well as the H-1 NMR spectra of single wheat kernels, wheat flour, and wheat methanol extracts were analysed to elucidate the metabolic development...

  16. The MAS Six Years in Power in Bolivia

    Directory of Open Access Journals (Sweden)

    Ton Salman

    2012-04-01

    Full Text Available Review Essay of:– The Rise of Evo Morales and the MAS, by Sven Harten. London/New York: Zed Books, 2011.– Evo Morales and the Movimiento al Socialismo in Bolivia; The First Term in Context, edited by Adrian J. Pearce. London, Institute for the Study of the Americas, 2011.– El estado de derecho como tiranía, by Luis Tapia. La Paz: CIDES/UMSA, 2011.– From Rebellion to Reform in Bolivia: Class Struggle, Indigenous Liberation and the Politics of Evo Morales, by Jeffery R. Webber. Chicago: Haymarket Books, 2011.– La democracia desde los márgenes: Transformaciones en el campo político boliviano, by María Teresa Zegada, with Claudia Arce, Gabriela Canedo and Alber Quispe. La Paz: Muela del Diablo Editores/CLACSO, 2011.

  17. TOKSISITAS LETAL MOLUSKISIDA NIKLOSAMIDA PADA BENIH IKAN MAS (Cyprinus carpio

    Directory of Open Access Journals (Sweden)

    Yosmaniar Yosmaniar

    2009-04-01

    Full Text Available Penggunaan moluskisida untuk menanggulangi hama dalam budidaya tanaman padi yang semakin meningkat berpotensi mencemari lingkungan perairan, karena mengandung residu dari bahan aktifnya. Moluskisida niklosamida (C13H8Cl2N2O4 merupakan bahan aktif pestisida yang digunakan untuk memberantas hama keong mas atau siput murbei (Pomacea sp. di sawah. Dengan demikian, bahan tersebut memiliki potensi untuk mencemari lahan tempat usaha budidaya ikan. Penelitian ini bertujuan untuk mengetahui potensi toksisitas akut niklosamida terhadap benih ikan mas (Cyprinus carpio yang ditunjukkan oleh nilai Median Lethal Concentration (LC50 24, 48, dan 96 jam. Penelitian dilakukan di Instalasi Riset Lingkungan Perikanan Budidaya dan Toksikologi, Cibalagung-Bogor. Menggunakan ikan mas dengan bobot individu 2,47 ± 0,13 g. Moluskisida yang digunakan mengandung bahan aktif niklosamida 250g/L. Wadah pengujian berupa 21 unit akuarium kaca berukuran 40 cm x 20 cm x 20 cm yang dilengkapi aerasi serta saluran pemasukan dan pengeluaran. Jumlah ikan uji setiap wadah 10 ekor dengan peubah yang diukur adalah mortalitas ikan. Selama penelitian ikan tidak diberi makan. Tahapan penelitian terdiri atas penentuan nilai ambang atas-bawah, nilai lethal time dan LC50 -24, 48, 72, dan 96 jam. Data diolah dengan analisis probit program LC50. Hasil penelitian menunjukkan bahwa nilai LC50-24, 48, 72, dan 96 jam terhadap benih ikan mas adalah 0,8012 (0,7140—0,8990; 0,5999 (0,5356—0,6719; 0,4511 (0,4067—0,5004; dan 0,3849 mg/L (0,3684—0,4061. Hal ini menunjukkan niklosamida termasuk pestisida yang memiliki toksisitas sangat tinggi (golongan A. The use of molluscicide in aquatic as well as in terresterial agro ecosystem without properly controlled may produce detrimental effects on freshwater fisheries. Molluscicide utilization for golden apple snail (Pomacea sp. control in rice field has increased. The ingredient potencially has a possibility to pollute aquaculture water. The

  18. Food Waste Composting Study from Makanan Ringan Mas

    Science.gov (United States)

    Kadir, A. A.; Ismail, S. N. M.; Jamaludin, S. N.

    2016-07-01

    The poor management of municipal solid waste in Malaysia has worsened over the years especially on food waste. Food waste represents almost 60% of the total municipal solid waste disposed in the landfill. Composting is one of low cost alternative method to dispose the food waste. This study is conducted to compost the food waste generation in Makanan Ringan Mas, which is a medium scale industry in Parit Kuari Darat due to the lack knowledge and exposure of food waste recycling practice. The aim of this study is to identify the physical and chemical parameters of composting food waste from Makanan Ringan Mas. The physical parameters were tested for temperature and pH value and the chemical parameter are Nitrogen, Phosphorus and Potassium. In this study, backyard composting was conducted with 6 reactors. Tapioca peel was used as fermentation liquid and soil and coconut grated were used as the fermentation bed. Backyard composting was conducted with six reactors. The overall results from the study showed that the temperature of the reactors were within the range which are from 30° to 50°C. The result of this study revealed that all the reactors which contain processed food waste tend to produce pH value within the range of 5 to 6 which can be categorized as slightly acidic. Meanwhile, the reactors which contained raw food waste tend to produce pH value within the range of 7 to 8 which can be categorized as neutral. The highest NPK obtained is from Reactor B that process only raw food waste. The average value of Nitrogen is 48540 mg/L, Phosphorus is 410 mg/L and Potassium is 1550 mg/L. From the comparison with common chemical fertilizer, it shows that NPK value from the composting are much lower than NPK of the common chemical fertilizer. However, comparison with NPK of organic fertilizer shown only slightly difference value in NPK.

  19. Unified integration intervals for the structural characterization of oil, coal or fractions there of by 1h NMR and 13c NMR

    International Nuclear Information System (INIS)

    Avella, Eliseo; Fierro, Ricardo

    2010-01-01

    Based on an analysis of publications reported between 1972 and 2006, it became clear that there are inaccuracies in the limits of the ranges of integration that the authors assigned to signals in nuclear magnetic resonance (NMR) to the structural characterization of petroleum, coals and their derived fractions, from their hydrogen (1H NMR) and carbon (13C NMR) spectra. Consequently, consolidated limits were determined for the integration of 1H NMR spectra and 13C NMR of these samples using a statistical treatment applied to the limits of integration intervals already published. With these unified limits, correlation NMR charts were developed that are useful for the allocation of the integral at such intervals, and at smaller intervals defined in terms of the intersection between different assignments. Also raised equations needed to establish the integral attributable to specific fragments in an attempt to make a more accurate structural characterization from NMR spectra of oil, coal or fractions derived.

  20. Supra-molecular structure and chemical reactivity of cellulose I studied using CP/MAS (sup)13 C-NMR

    CSIR Research Space (South Africa)

    Chunilall, Viren

    2013-08-01

    Full Text Available There are a few traditional methods of analysing the chemical properties of cellulose I. Some of these methods include the Permanganate number determination, which is used to obtain the lignin content of the pulp [12]. The acid insoluble lignin content... – Fundamental Aspects 88 [10] Fengel D, Wegener G. Wood Chemistry, Ultrastructure, Reactions, Walter de Gruyter; 1984. [11] Uhlmann T. Ullmann's encyclopedia of industrial chemistry. Paper and Pulp. 1991; 18 (A). [12] Permanganate number of pulp, Tappi T...

  1. Fluid-Rock Characterization and Interactions in NMR Well Logging

    Energy Technology Data Exchange (ETDEWEB)

    George J. Hirasaki; Kishore K. Mohanty

    2005-09-05

    The objective of this report is to characterize the fluid properties and fluid-rock interactions that are needed for formation evaluation by NMR well logging. The advances made in the understanding of NMR fluid properties are summarized in a chapter written for an AAPG book on NMR well logging. This includes live oils, viscous oils, natural gas mixtures, and the relation between relaxation time and diffusivity. Oil based drilling fluids can have an adverse effect on NMR well logging if it alters the wettability of the formation. The effect of various surfactants on wettability and surface relaxivity are evaluated for silica sand. The relation between the relaxation time and diffusivity distinguishes the response of brine, oil, and gas in a NMR well log. A new NMR pulse sequence in the presence of a field gradient and a new inversion technique enables the T{sub 2} and diffusivity distributions to be displayed as a two-dimensional map. The objectives of pore morphology and rock characterization are to identify vug connectivity by using X-ray CT scan, and to improve NMR permeability correlation. Improved estimation of permeability from NMR response is possible by using estimated tortuosity as a parameter to interpolate between two existing permeability models.

  2. Structural diversity of solid dispersions of acetylsalicylic acid as seen by solid-state NMR.

    Science.gov (United States)

    Policianova, Olivia; Brus, Jiri; Hruby, Martin; Urbanova, Martina; Zhigunov, Alexander; Kredatusova, Jana; Kobera, Libor

    2014-02-03

    Solid dispersions of active pharmaceutical ingredients are of increasing interest due to their versatile use. In the present study polyvinylpyrrolidone (PVP), poly[N-(2-hydroxypropyl)-metacrylamide] (pHPMA), poly(2-ethyl-2-oxazoline) (PEOx), and polyethylene glycol (PEG), each in three Mw, were used to demonstrate structural diversity of solid dispersions. Acetylsalicylic acid (ASA) was used as a model drug. Four distinct types of the solid dispersions of ASA were created using a freeze-drying method: (i) crystalline solid dispersions containing nanocrystalline ASA in a crystalline PEG matrix; (ii) amorphous glass suspensions with large ASA crystallites embedded in amorphous pHPMA; (iii) solid solutions with molecularly dispersed ASA in rigid amorphous PVP; and (iv) nanoheterogeneous solid solutions/suspensions containing nanosized ASA clusters dispersed in a semiflexible matrix of PEOx. The obtained structural data confirmed that the type of solid dispersion can be primarily controlled by the chemical constitutions of the applied polymers, while the molecular weight of the polymers had no detectable impact. The molecular structure of the prepared dispersions was characterized using solid-state NMR, wide-angle X-ray scattering (WAXS), and differential scanning calorimetry (DSC). By applying various (1)H-(13)C and (1)H-(1)H correlation experiments combined with T1((1)H) and T1ρ((1)H) relaxation data, the extent of the molecular mixing was determined over a wide range of distances, from intimate intermolecular contacts (0.1-0.5 nm) up to the phase-separated nanodomains reaching ca. 500 nm. Hydrogen-bond interactions between ASA and polymers were probed by the analysis of (13)C and (15)N CP/MAS NMR spectra combined with the measurements of (1)H-(15)N dipolar profiles. Overall potentialities and limitations of individual experimental techniques were thoroughly evaluated.

  3. Tracing compartment exchange by NMR diffusometry: Water in lithium-exchanged low-silica X zeolites

    Science.gov (United States)

    Lauerer, A.; Kurzhals, R.; Toufar, H.; Freude, D.; Kärger, J.

    2018-04-01

    The two-region model for analyzing signal attenuation in pulsed field gradient (PFG) NMR diffusion studies with molecules in compartmented media implies that, on their trajectory, molecules get from one region (one type of compartment) into the other one with a constant (i.e. a time-invariant) probability. This pattern has proved to serve as a good approach for considering guest diffusion in beds of nanoporous host materials, with the two regions ("compartments") identified as the intra- and intercrystalline pore spaces. It is obvious, however, that the requirements of the application of the two-region model are not strictly fulfilled given the correlation between the covered diffusion path lengths in the intracrystalline pore space and the probability of molecular "escape" from the individual crystallites. On considering water diffusion in lithium-exchanged low-silica X zeolite, we are now assuming a different position since this type of material is known to offer "traps" in the trajectories of the water molecules. Now, on attributing the water molecules in the traps and outside of the traps to these two types of regions, we perfectly comply with the requirements of the two-region model. We do, moreover, benefit from the option of high-resolution measurements owing to the combination of magic angle spinning (MAS) with PFG NMR. Data analysis via the two-region model under inclusion of the influence of nuclear magnetic relaxation yields satisfactory agreement between experimental evidence and theoretical estimates. Limitations in accuracy are shown to result from the fact that mass transfer outside of the traps is too complicated for being adequately reflected by simple Fick's laws with but one diffusivity.

  4. Solid state NMR studies for a new carbonization process with high temperature preheating

    Science.gov (United States)

    Saito, Koji; Hatakeyama, Moriaki; Komaki, Ikuo; Katoh, Kenji

    2002-01-01

    A new carbonization process with rapid preheating and coke discharging at medium temperature has been developed in Japan. The result of this process shows that even when no or slightly coking coal is by 50 wt% the coking property is improved and a coking coke with cold strength usable at blast furnace can be manufactured with the new carbonization process. The mechanism of the coking property improvement was examined by coal properties using mainly solid state NMR ( 1H CRAMPS and 13C SPE/MAS, CP/MAS) and NMR imaging (single point imaging, in-situ imaging). It has been clarified that the molecular structure of coal is relaxed by the rapid heating treatment and, in addition, there is a close relation between hydrogen bonding and relaxation of the molecular structure of coal.

  5. 13C and 15N CP/MAS, 1H-15N SCT CP/MAS and FTIR spectroscopy as tools for qualitative detection of the presence of zwitterionic and non-ionic forms of ansa-macrolide 3-formylrifamycin SV and its derivatives in solid state.

    Science.gov (United States)

    Przybylski, Piotr; Pyta, Krystian; Klich, Katarzyna; Schilf, Wojciech; Kamieński, Bohdan

    2014-01-01

    (13)C, (15)N CP/MAS, including (1)H-(13)C and (1)H-(15)N short contact time CP/MAS experiments, and FTIR methods were applied for detailed structural characterization of ansa-macrolides as 3-formylrifamycin SV (1) and its derivatives (2-6) in crystal and in powder forms. Although HPLC chromatograms for 2/CH3 OH and 2/CH3 CCl3 were the same for rifampicin crystals dissolved in respective solvents, the UV-vis data recorded for them were different in 300-375 nm region. Detailed solid state (13)C and (15)N CP/MAS NMR and FTIR studies revealed that rifampicin (2), in contrast to 3-formylrifamycin SV (1) and its amino derivatives (3-6), can occur in pure non-ionic or zwitterionic forms in crystal and in pure these forms or a mixture of them in a powder. Multinuclear CP/MAS and FTIR studies demonstrated also that 3-6 derivatives were present exclusively in pure zwitterionic forms, both in powder and in crystal. On the basis of the solid state NMR and FTIR studies, two conformers of 3-formylrifamycin SV were detected in powder form due to the different orientations of carbonyl group of amide moiety. The PM6 molecular modeling at the semi-empirical level of theory, allowed visualization the most energetically favorable non-ionic and zwitterionic forms of 1-6 antibiotics, strongly stabilized via intramolecular H-bonds. FTIR studies indicated that the originally adopted forms of these type antibiotics in crystal or in powder are stable in standard laboratory conditions in time. The results presented point to the fact that because of a possible presence of two forms of rifampicin (compound 2), quantification of the content of this antibiotic in relevant pharmaceuticals needs caution. Copyright © 2013 John Wiley & Sons, Ltd.

  6. Synthesis and NMR characterization of SAPO-35 from non-aqueous systems using hexamethyleneimine template

    International Nuclear Information System (INIS)

    Venkatathri, N.

    2005-01-01

    SAPO-35 was synthesized using hexamethyleneimine template in non-aqueous systems. X-ray diffraction and scanning electron micrograph analysis shows the synthesized sample is pure and well crystalline. Presence of four stages (1.6%, 0.8%, 7.8% and 8.4%) of weight loss is observed by TG/DTA analysis. FT-IR analysis in the framework region shows the presence of tetrahedral T-O-T vibrations is similar to the other known aluminophosphate molecular sieves. FT-IR spectrum in the -OH region shows stretching vibrations at 3631, 3604 and 3580 cm -1 can be assigned to OH groups in bigger cages near S6R, in bigger cages near D6R and those actually confined inside the D6R, respectively. The spectra for the as-synthesized sample show a single symmetrical 27 Al MAS NMR line at δ = 36.26 indicating the presence of a single tetrahedral aluminium species. Where as 29 Si and 31 P MAS NMR shows the presence of two peaks in both at (-89.9 and -95.15 ppm) and (-34.01 and -40.45 ppm) due to the Si substitution of P present in two different locations in double 6 ring (D6R) and in single 6 ring (S6R). 27 Al 3Q-MAS NMR shows two peaks for environmentally different tetrahedral aluminium atoms. This is the first time we are showing such a fact which is not observable using ordinary MAS NMR

  7. Angiotensin-(1-7)/Mas axis integrity is required for the expression of object recognition memory.

    Science.gov (United States)

    Lazaroni, Thiago L N; Raslan, Ana Cláudia S; Fontes, Walkiria R P; de Oliveira, Marilene L; Bader, Michael; Alenina, Natalia; Moraes, Márcio F D; Dos Santos, Robson A; Pereira, Grace S

    2012-01-01

    It has been shown that the brain has its own intrinsic renin-angiotensin system (RAS) and angiotensin-(1-7) (Ang-(1-7)) is particularly interesting, because it appears to counterbalance most of the Ang II effects. Ang-(1-7) exerts its biological function through activation of the G-protein-coupled receptor Mas. Interestingly, hippocampus is one of the regions with higher expression of Mas. However, the role of Ang-(1-7)/Mas axis in hippocampus-dependent memories is still poorly understood. Here we demonstrated that Mas ablation, as well as the blockade of Mas in the CA1-hippocampus, impaired object recognition memory (ORM). We also demonstrated that the blockade of Ang II receptors AT1, but not AT2, recovers ORM impairment of Mas-deficient mice. Considering that high concentrations of Ang-(1-7) may activate AT1 receptors, nonspecifically, we evaluate the levels of Ang-(1-7) and its main precursors Ang I and Ang II in the hippocampus of Mas-deficient mice. The Ang I and Ang II levels are unaltered in the whole hipocampus of MasKo. However, Ang-(1-7) concentration is increased in the whole hippocampus of MasKo mice, as well as in the CA1 area. Taken together, our findings suggest that the functionality of the Ang-(1-7)/Mas axis is essential for normal ORM processing. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. NMR studies of metallic tin confined within porous matrices

    International Nuclear Information System (INIS)

    Charnaya, E. V.; Tien, Cheng; Lee, M. K.; Kumzerov, Yu. A.

    2007-01-01

    119 Sn NMR studies were carried out for metallic tin confined within synthetic opal and porous glass. Tin was embedded into nanoporous matrices in the melted state under pressure. The Knight shift for liquid confined tin was found to decrease with decreasing pore size. Correlations between NMR line shapes, Knight shift, and pore filling were observed. The melting and freezing phase transitions of tin under confinement were studied through temperature dependences of NMR signals upon warming and cooling. Melting of tin within the opal matrix agreed well with the liquid skin model suggested for small isolated particles. The influence of the pore filling on the melting process was shown

  9. Progress in proton-detected solid-state NMR (SSNMR): Super-fast 2D SSNMR collection for nano-mole-scale proteins

    Science.gov (United States)

    Ishii, Yoshitaka; Wickramasinghe, Ayesha; Matsuda, Isamu; Endo, Yuki; Ishii, Yuji; Nishiyama, Yusuke; Nemoto, Takahiro; Kamihara, Takayuki

    2018-01-01

    Proton-detected solid-state NMR (SSNMR) spectroscopy has attracted much attention due to its excellent sensitivity and effectiveness in the analysis of trace amounts of amyloid proteins and other important biological systems. In this perspective article, we present the recent sensitivity limit of 1H-detected SSNMR using "ultra-fast" magic-angle spinning (MAS) at a spinning rate (νR) of 80-100 kHz. It was demonstrated that the high sensitivity of 1H-detected SSNMR at νR of 100 kHz and fast recycling using the paramagnetic-assisted condensed data collection (PACC) approach permitted "super-fast" collection of 1H-detected 2D protein SSNMR. A 1H-detected 2D 1H-15N correlation SSNMR spectrum for ∼27 nmol of a uniformly 13C- and 15N-labeled GB1 protein sample in microcrystalline form was acquired in only 9 s with 50% non-uniform sampling and short recycle delays of 100 ms. Additional data suggests that it is now feasible to detect as little as 1 nmol of the protein in 5.9 h by 1H-detected 2D 1H-15N SSNMR at a nominal signal-to-noise ratio of five. The demonstrated sensitivity is comparable to that of modern solution protein NMR. Moreover, this article summarizes the influence of ultra-fast MAS and 1H-detection on the spectral resolution and sensitivity of protein SSNMR. Recent progress in signal assignment and structural elucidation by 1H-detected protein SSNMR is outlined with both theoretical and experimental aspects.

  10. 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.)

  11. Distributed Cooperation Solution Method of Complex System Based on MAS

    Science.gov (United States)

    Weijin, Jiang; Yuhui, Xu

    To adapt the model in reconfiguring fault diagnosing to dynamic environment and the needs of solving the tasks of complex system fully, the paper introduced multi-Agent and related technology to the complicated fault diagnosis, an integrated intelligent control system is studied in this paper. Based on the thought of the structure of diagnostic decision and hierarchy in modeling, based on multi-layer decomposition strategy of diagnosis task, a multi-agent synchronous diagnosis federation integrated different knowledge expression modes and inference mechanisms are presented, the functions of management agent, diagnosis agent and decision agent are analyzed, the organization and evolution of agents in the system are proposed, and the corresponding conflict resolution algorithm in given, Layered structure of abstract agent with public attributes is build. System architecture is realized based on MAS distributed layered blackboard. The real world application shows that the proposed control structure successfully solves the fault diagnose problem of the complex plant, and the special advantage in the distributed domain.

  12. Multi-Robot Remote Interaction with FS-MAS

    Directory of Open Access Journals (Sweden)

    Yunliang Jiang

    2013-02-01

    Full Text Available The need to reduce bandwidth, improve productivity, autonomy and the scalability in multi-robot teleoperation has been recognized for a long time. In this article we propose a novel finite state machine mobile agent based on the network interaction service model, namely FS-MAS. This model consists of three finite state machines, namely the Finite State Mobile Agent (FS-Agent, which is the basic service module. The Service Content Finite State Machine (Content-FS, using the XML language to define workflow, to describe service content and service computation process. The Mobile Agent computation model Finite State Machine (MACM-FS, used to describe the service implementation. Finally, we apply this service model to the multi-robot system, the initial realization completing complex tasks in the form of multi-robot scheduling. This demonstrates that the robot has greatly improved intelligence, and provides a wide solution space for critical issues such as task division, rational and efficient use of resource and multi-robot collaboration.

  13. 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.

  14. 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

  15. 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.

  16. ECG gated NMR-CT for cardiovascular diseases

    International Nuclear Information System (INIS)

    Nishikawa, J.; Machida, K.; Iio, M.; Yoshimoto, N.; Sugimoto, T.; Kawaguchi, H.; Mano, H.

    1984-01-01

    The authors applied NMR-CT to cardiac study with ECG gated technique to evaluate the left ventricular (LV) function and compared it with cardiovascular nuclear medicine study (NM). The NMR-CT machine has resistive air-core magnet with 0.15 Tesla. The saturation recovery image or inversion recovery image were obtained as 256 x 256 matrix and 15 mm in thickness. The study population was ten patients who were evaluated both by NMR image and by NM performed within one week interval. The heart muscle was able to be visualized without any contrast material nor radioisotopes in inversion recovery images, whereas saturation recovery images failed to separate heart muscle from blood pool. The wall motions of LV in both methods were well correlated except for inferior wall. The values of ejection fraction in NMR image were moderately low, but two modalities showed satisfactory correlation (r=0.85). The region of myocardial infarction was revealed as wall thinning and/or wall motion abnormality. It is still preliminary to draw a conclusion, however, it can be said that in the evaluation of LV function, method by NMR might be of equal value to those of NM. It can be certain that eventually gated NMR-CT will become more effective method for various aspects of cardiovascular evaluation

  17. A Hybrid Solid-State NMR and Electron Microscopy Structure-Determination Protocol for Engineering Advanced para-Crystalline Optical Materials

    NARCIS (Netherlands)

    Thomas, Brijith; Rombouts, Jeroen; Oostergetel, Gert T.; Gupta, Karthick B.S.S.; Buda, Francesco; Lammertsma, Koop; Orru, Romano; de Groot, Huub J.M.

    2017-01-01

    Hybrid magic-angle spinning (MAS) NMR spectroscopy and TEM were demonstrated for de novo structure determination of para-crystalline materials with a bioinspired fused naphthalene diimide (NDI)–salphen–phenazine prototype light-harvesting compound. Starting from chiral building blocks with C2

  18. High-resolution magic angle spinning (1)H NMR spectroscopy of metabolic changes in rabbit lens after treatment with dexamethasone combined with UVB exposure

    Czech Academy of Sciences Publication Activity Database

    Seather, O.; Risa, O.; Čejková, Jitka; Krane, J.; Midelfart, A.

    2004-01-01

    Roč. 242, - (2004), s. 1000-1007 ISSN 0721-832X R&D Projects: GA ČR GA304/03/0419 Institutional research plan: CEZ:AV0Z5008914 Keywords : HR-MAS 1H NMR Subject RIV: FF - HEENT, Dentistry Impact factor: 1.513, year: 2004

  19. Chemical structure changes in coals after low-temperature oxidation and demineralization by acid treatment as revealed by high resolution solid state 13C NMR

    International Nuclear Information System (INIS)

    Tekely, P.; Nicole, D.; Delpuech, J.-J.; Totino, E.; Muller, J.F.

    1987-01-01

    13 C CP/MAS NMR has been used for characterization of chemical structure changes in coals after low-temperature oxidation and prolonged demineralization by acid treatment. In both cases the changes take place mainly in the aliphatic part of coal molecules. 21 refs.; 3 figs.; 2 tabs

  20. Isotope labeling strategies for NMR studies of RNA

    International Nuclear Information System (INIS)

    Lu, Kun; Miyazaki, Yasuyuki; Summers, Michael F.

    2010-01-01

    The known biological functions of RNA have expanded in recent years and now include gene regulation, maintenance of sub-cellular structure, and catalysis, in addition to propagation of genetic information. As for proteins, RNA function is tightly correlated with structure. Unlike proteins, structural information for larger, biologically functional RNAs is relatively limited. NMR signal degeneracy, relaxation problems, and a paucity of long-range 1 H- 1 H dipolar contacts have limited the utility of traditional NMR approaches. Selective isotope labeling, including nucleotide-specific and segmental labeling strategies, may provide the best opportunities for obtaining structural information by NMR. Here we review methods that have been developed for preparing and purifying isotopically labeled RNAs, as well as NMR strategies that have been employed for signal assignment and structure determination.

  1. Determination of moisture in fiber reinforced composites using pulsed NMR

    International Nuclear Information System (INIS)

    Matzkanin, G.A.

    1982-01-01

    Nuclear magnetic resonance (NMR) signals from hydrogen atoms in two organic matrix composite systems subjected to environmental conditioning at 51.6 C (125 F) and 95% relative humidity were examined. The composites were 8 ply, + or - 45 deg laminates fabricated from SP 250 resin/S2 glass fiber and Reliabond 9350 resin/Kevlar 49 fiber. Free induction decay NMR signals from the composite specimens consisted of a large amplitude, fast decaying component associated with hydrogen in rigid polymer molecules and a lower amplitude, slower decaying component associated with hydrogen in the mobile absorbed moisture molecules. The absorbed moisture NMR signals consists of distinct multiple components which were attributed to moisture in various states of molecular binding. Particularly complex free induction decay signals were observed from Kevlar composite as well as from Kevlar fiber. Good correlation was obtained between the NMR signal amplitude and the dry weight moisture percentage for both composite systems. Results of destructive tensile tests were examined

  2. Evaluation of thermoplastic starch/MMT nanocomposites by nuclear magnetic resonance (NMR)

    International Nuclear Information System (INIS)

    Schlemmer, D.; Rodrigues, Tiago C.A.F.; Resck, I.S.; Sales, M.J.A.

    2010-01-01

    Starch has been studied for replace petrochemical plastics for short shelf life. However, the starch films have limitations: sensitivity to moisture and poor mechanical strength. This can be improved by incorporating loads such as montmorillonite, forming nanocomposites. Nanocomposites were prepared with 1, 3, 5 and 10% of montmorillonite, using vegetable oils of Brazilian Cerrado as plasticizers. The NMR spectra of oils are similar, but the intensities of the signals varying with the proportion of fatty acids. The molar mass of the oils was also calculated by NMR. The spectrum of CP/MAS 13 C NMR for starch presented a duplet in 97 and 98 ppm, on the amorphous domains of C-1, indicating a crystal type A. The spectra of the nanocomposites are similar to those of starch and oils. No new peaks appear, suggesting that there are no strong chemical bonds between components. (author)

  3. E/Z MAS: An easy-to-use computerized materials control and accountability system

    International Nuclear Information System (INIS)

    Anderson, L.K.; Boor, M.G.; Hurford, J.M.; Landry, R.P.; Martinez, B.J.; Solem, A.M.; Whiteson, R.; Zardecki, A.

    1998-01-01

    Nuclear facilities that handle and process nuclear materials are required to track their nuclear holdings and to keep adequate records that manage and control the inventory of those holdings. The complexity of a system that does this job is directly proportional to the complexity of the facility's operations. This paper describes an approach to computerized materials protection, control, and accountability (MPC and A) that was introduced by Los Alamos National Laboratory (LANL) in the fall of 1997. This new system, E/Z MAS, is the latest addition to the LANL suite of computerized MPC and A tools, which also includes the CoreMAS system. E/Z MAS was initially designed to address the needs of those facilities that have small to modest MPC and A needs but has been expanded to provide full functionality for any facility. The system name, E/Z MAS, reflects the system's easy-to-use characteristics, which include ease of installation and ease of software maintenance. Both CoreMAS and E/Z MAS have been provided to facilities in the Former Soviet Union to assist them in implementing a computerized MPC and A system that meets their needs. In this paper the authors will address the functionality of CoreMAS and E/Z MAS, and an argument in favor of intranet-based material control and accountability will be advanced

  4. Evidence for Heterodimerization and Functional Interaction of the Angiotensin Type 2 Receptor and the Receptor MAS

    DEFF Research Database (Denmark)

    Leonhardt, Julia; Villela, Daniel C.; Teichmann, Anke

    2017-01-01

    The angiotensin type 2 receptor (AT2R) and the receptor MAS are receptors of the protective arm of the renin-angiotensin system. They mediate strikingly similar actions. Moreover, in various studies, AT2R antagonists blocked the effects of MAS agonists and vice versa. Such cross-inhibition may in...

  5. Assessment of 1H NMR-based metabolomics analysis for normalization of urinary metals against creatinine.

    Science.gov (United States)

    Cassiède, Marc; Nair, Sindhu; Dueck, Meghan; Mino, James; McKay, Ryan; Mercier, Pascal; Quémerais, Bernadette; Lacy, Paige

    2017-01-01

    Proton nuclear magnetic resonance ( 1 H NMR, or NMR) spectroscopy and inductively coupled plasma-mass spectrometry (ICP-MS) are commonly used for metabolomics and metal analysis in urine samples. However, creatinine quantification by NMR for the purpose of normalization of urinary metals has not been validated. We assessed the validity of using NMR analysis for creatinine quantification in human urine samples in order to allow normalization of urinary metal concentrations. NMR and ICP-MS techniques were used to measure metabolite and metal concentrations in urine samples from 10 healthy subjects. For metabolite analysis, two magnetic field strengths (600 and 700MHz) were utilized. In addition, creatinine concentrations were determined by using the Jaffe method. Creatinine levels were strongly correlated (R 2 =0.99) between NMR and Jaffe methods. The NMR spectra were deconvoluted with a target database containing 151 metabolites that are present in urine. A total of 50 metabolites showed good correlation (R 2 =0.7-1.0) at 600 and 700MHz. Metal concentrations determined after NMR-measured creatinine normalization were comparable to previous reports. NMR analysis provided robust urinary creatinine quantification, and was sufficient for normalization of urinary metal concentrations. We found that NMR-measured creatinine-normalized urinary metal concentrations in our control subjects were similar to general population levels in Canada and the United Kingdom. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Characterization of Two Distinct Amorphous Forms of Valsartan by Solid-State NMR.

    Science.gov (United States)

    Skotnicki, Marcin; Apperley, David C; Aguilar, Juan A; Milanowski, Bartłomiej; Pyda, Marek; Hodgkinson, Paul

    2016-01-04

    Valsartan (VAL) is an antihypertensive drug marketed in an amorphous form. Amorphous materials can have different physicochemical properties depending on preparation method, thermal history, etc., but the nature of such materials is difficult to study by diffraction techniques. This study characterizes two different amorphous forms of valsartan (AR and AM) using solid-state NMR (SSNMR) as a primary investigation tool, supported by solution-state NMR, FT-IR, TMDSC, and dissolution tests. The two forms are found to be clearly distinct, with a significantly higher level of structural arrangement in the AR form, as observed in (13)C, (15)N, and (1)H SSNMR. (13)C and (15)N NMR indicates that the fully amorphous material (AM) contains an approximately equal ratio of cis-trans conformers about the amide bond, whereas the AR form exists mainly as one conformer, with minor conformational "defects". (1)H ultrafast MAS NMR shows significant differences in the hydrogen bonding involving the tetrazole and acid hydrogens between the two materials, while (15)N NMR shows that both forms exist as a 1,2,3,4-tetrazole tautomer. NMR relaxation times show subtle differences in local and bulk molecular mobility, which can be connected with the glass transition, the stability of the glassy material, and its response to aging. Counterintuitively the fully amorphous material is found to have a significantly lower dissolution rate than the apparently more ordered AR material.

  7. Application of NMR Spectroscopy in the Analysis of Petroleum Derivatives and Products

    Directory of Open Access Journals (Sweden)

    Parlov Vuković, J.

    2012-11-01

    Full Text Available Complex chemical composition and physical properties of oil and fuel make their complete cha racterization very difficult. Components present in oil and oil products differ in structure, size, po larity and functionality. The presence and structure of specific hydrocarbons in final products depend on the processing procedure and type of the fuel. In order to predict or improve fuel pro perties it is necessary to determine its composition. Thus, new and more sophisticated analytical methods and procedures are constantly being developed. NMR spectroscopy plays a significant role in analysis and identification of complex hydrocarbon mixtures of petroleum and petroleum products. In this review, we describe the application of NMR spectroscopy for analyzing gasoline and diesel fuels. Hence, by using NMR spectroscopy it is possible to determine gasoline composition and presence of benzene and oxygenates, as well as some important physical characteristics of gasoli ne such as the research octane number. An application of different NMR techniques made it pos sible to characterize diesel fuels and middle oil distillates from various refineries. Data so obtained can be used in combination with statistical methods to predict fuel properties and to monitor pro- duction processes in the petroleum industry. NMR spectroscopy has proven useful in analysis of FAME which has recently been used as an ecologically acceptable alternative fuel. Furthermore, techniques such as CP/MAS for characterization of solid state oil-geochemical samples are inclu- ded. Also, possibilities of using NMR spectroscopy in the analysis of polymeric additives are di- scussed.

  8. Angiotensin-(1-7)/Mas axis modulates fear memory and extinction in mice.

    Science.gov (United States)

    Lazaroni, Thiago Luiz do Nascimento; Bastos, Cristiane Perácio; Moraes, Márcio Flávio Dutra; Santos, Robson Souza; Pereira, Grace Schenatto

    2016-01-01

    Inappropriate defense-alerting reaction to fear is a common feature of neuropsychiatric diseases. Therefore, impairments in brain circuits, as well as in molecular pathways underlying the neurovegetative adjustments to fear may play an essential role on developing neuropsychiatric disorders. Here we tested the hypothesis that interfering with angiotensin-(1-7) [Ang-(1-7)]/Mas receptor axis homeostasis, which appears to be essential to arterial pressure control, would affect fear memory and extinction. Mas knockout (MasKO) mice, in FVB/N background, showed normal cued fear memory and extinction, but increased freezing in response to context. Next, as FVB/N has poor performance in contextual fear memory, we tested MasKO in mixed 129xC57BL/6 background. MasKO mice behaved similarly to wild-type (WT), but memory extinction was slower in contextual fear conditioning to a weak protocol (1CS/US). In addition, delayed extinction in MasKO mice was even more pronounced after a stronger protocol (3CS/US). We showed previously that Angiotensin II receptor AT1 antagonist, losantan, rescued object recognition memory deficit in MasKO mice. Here, losartan was also effective. Memory extinction was accelerated in MasKO mice after treatment with losartan. In conclusion, we showed for the first time that Ang-(1-7)/Mas axis may modulate fear memory extinction. Furthermore, we suggest MasKO mice as an animal model to study post-traumatic stress disorder (PTSD). Copyright © 2015 Elsevier Inc. All rights reserved.

  9. 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

  10. 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.

  11. 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

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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...

  17. Solid-state 27Al and 29Si NMR characterization of hydrates formed in calcium aluminate-silica fume mixtures

    International Nuclear Information System (INIS)

    Pena, P.; Rivas Mercury, J.M.; Aza, A.H. de; Turrillas, X.; Sobrados, I.; Sanz, J.

    2008-01-01

    Partially deuterated Ca 3 Al 2 (SiO 4 ) y (OH) 12-4y -Al(OH) 3 mixtures, prepared by hydration of Ca 3 Al 2 O 6 (C 3 A), Ca 12 Al 14 O 33 (C 12 A 7 ) and CaAl 2 O 4 (CA) phases in the presence of silica fume, have been characterized by 29 Si and 27 Al magic-angle spinning-nuclear magnetic resonance (MAS-NMR) spectroscopies. NMR spectroscopy was used to characterize anhydrous and fully hydrated samples. In hydrated compounds, Ca 3 Al 2 (OH) 12 and Al(OH) 3 phases were detected. From the quantitative analysis of 27 Al NMR signals, the Al(OH) 3 /Ca 3 Al 2 (OH) 12 ratio was deduced. The incorporation of Si into the katoite structure, Ca 3 Al 2 (SiO 4 ) 3-x (OH) 4x , was followed by 27 Al and 29 Si NMR spectroscopies. Si/OH ratios were determined from the quantitative analysis of 27 Al MAS-NMR components associated with Al(OH) 6 and Al(OSi)(OH) 5 environments. The 29 Si NMR spectroscopy was also used to quantify the unreacted silica and amorphous calcium aluminosilicate hydrates formed, C-S-H and C-A-S-H for short. From 29 Si NMR spectra, the amount of Si incorporated into different phases was estimated. Si and Al concentrations, deduced by NMR, transmission electron microscopy, energy dispersive spectrometry, and Rietveld analysis of both X-ray and neutron data, indicate that only a part of available Si is incorporated in katoite structures. - Graphical abstract: Transmission electron micrograph of CaAl 2 O 4 -microsilica mixture hydrated at 90 deg. C for 31 days showing a cubic Ca 3 Al 2.0±0.2 (SiO 4 ) 0.9±0.2 (OH) 1.8 crystal surrounded by unreacted amorphous silica spheres

  18. The application of 199Hg NMR and 199mHg perturbed angular correlation (PAC) spectroscopy to define the biological chemistry of HgII

    DEFF Research Database (Denmark)

    Iranzo, Olga; Thulstrup, Peter Waaben; Ryu, Seung-baek

    2007-01-01

    The use of de novo designed peptides is a powerful strategy to elucidate HgII-protein interactions and to gain insight into the chemistry of HgII in biological systems. Cysteine derivatives of the designed -helical peptides of the TRI family [Ac-G-(LaKbAcLdEeEfKg)4-G-NH2] bind HgII at high p...... to characterize the distinct species that are generated under different pH conditions and peptide TRI L9C/HgII ratios. These studies prove for the first time the formation of [Hg{(TRI L9C)2-(TRI L9C H)}], a dithiolate-HgII complex in the hydrophobic interior of the three-stranded coiled coil (TRI L9C)3. 199Hg NMR...

  19. High-resolution 1H NMR spectroscopy of fish muscle, eggs and small whole fish via Hadamard-encoded intermolecular multiple-quantum coherence.

    Directory of Open Access Journals (Sweden)

    Honghao Cai

    Full Text Available BACKGROUND AND PURPOSE: Nuclear magnetic resonance (NMR spectroscopy has become an important technique for tissue studies. Since tissues are in semisolid-state, their high-resolution (HR spectra cannot be obtained by conventional NMR spectroscopy. Because of this restriction, extraction and high-resolution magic angle spinning (HR MAS are widely applied for HR NMR spectra of tissues. However, both of the methods are subject to limitations. In this study, the feasibility of HR (1H NMR spectroscopy based on intermolecular multiple-quantum coherence (iMQC technique is explored using fish muscle, fish eggs, and a whole fish as examples. MATERIALS AND METHODS: Intact salmon muscle tissues, intact eggs from shishamo smelt and a whole fish (Siamese algae eater are studied by using conventional 1D one-pulse sequence, Hadamard-encoded iMQC sequence, and HR MAS. RESULTS: When we use the conventional 1D one-pulse sequence, hardly any useful spectral information can be obtained due to the severe field inhomogeneity. By contrast, HR NMR spectra can be obtained in a short period of time by using the Hadamard-encoded iMQC method without shimming. Most signals from fatty acids and small metabolites can be observed. Compared to HR MAS, the iMQC method is non-invasive, but the resolution and the sensitivity of resulting spectra are not as high as those of HR MAS spectra. CONCLUSION: Due to the immunity to field inhomogeneity, the iMQC technique can be a proper supplement to HR MAS, and it provides an alternative for the investigation in cases with field distortions and with samples unsuitable for spinning. The acquisition time of the proposed method is greatly reduced by introduction of the Hadamard-encoded technique, in comparison with that of conventional iMQC method.

  20. Topotactic transformations of sodalite cages: synthesis and NMR study of mixed salt-free and salt-bearing sodalites.

    Science.gov (United States)

    Trill, Henning; Eckert, Hellmut; Srdanov, Vojislav I

    2002-07-17

    A series of mixed sodalite samples, Na(8)[Al(6)Si(6)O(24)]Br(x).(H(3)O(2))(2-x), with the unit cell stoichiometries varying in the 0 < x <2 region, was made by hydrothermal synthesis and subsequently transformed into Na(6+x)[Al(6)Si(6)O(24)]Br(x).(4H(2)O)(2-x) and Na(6+x)[Al(6)Si(6)O(24)]Br(x).circle(2-x) sodalites. Here, circle refers to an empty sodalite cage. The three series, referred hereafter to as the Br/basic, Br/hydro, and Br/dry series, were characterized by powder diffraction X-ray and by (23)Na, (27)Al, and (81)Br magic angle spinning (MAS) NMR and high-resolution triple quantum (TQ) MAS NMR spectroscopy. We determined that incorporation of Br(-) anions is 130 times more preferred than incorporation of H(3)O(2)(-) anions during the formation of sodalite cages, which permitted precise control of the halide content in the solid. Monotonic trends in chemical shifts were observed as a function of cage occupancy, reflecting continuous changes in structural parameters. A linear correlation between (81)Br chemical shift and lattice constant with a slope of -86 ppm/A was observed for all three series. Likewise, (23)Na chemical shifts for Na(+) cations in salt-bearing sodalite cages correlate linearly with the lattice constant. Both results indicate a universal dependence of the (23)Na and (81)Br chemical shifts on the Na-Br distance. The (27)Al chemical shifts of Br/basic and Br/hydro sodalites obey an established relation between delta(cs) and the average T-O-T bond angle of 0.72 ppm/degrees. Br/dry sodalites show two aluminum resonances, characterized by significantly different chemical shifts and quadrupolar interaction parameters. In that series, local symmetry distortions are evident from strong quadrupolar perturbations in the NMR spectra. P(Q) values for (27)Al vary between 0.8 MHz in Br/basic sodalites and 4.4 MHz in the Br/dry series caused by deviations from the tetrahedral symmetry of the salt-free sodalite cages. For (23)Na, P(Q) values of 0.8, 0

  1. Optimized strategy of 1H and 13C solid-state NMR methods to investigate water dynamics in soil organic matter as well as the influence of crystallinity of poly(methylene) segments

    Science.gov (United States)

    Bertmer, Marko; Jaeger, Alexander; Schwarz, Jette; Schaumann, Gabriele

    2010-05-01

    Water plays a crucial role in soil organic matter (SOM) having various different functions such as transport of material, elution of ,e. g., pollutants in soil, and also the sequestration of humic substances. Furthermore, the generation and quantification of hydrophilic and hydrophobic regions in soil has several effects on SOM which can also include the storage amount and time of certain material, especially chemical pollutants. The importance of water in soil is also documented by the multitude of scientific approaches to characterize soils including diffusion NMR to study the water channel structure in soil. Our focus is on the study of water dynamics and soil structure to elucidate mechanisms of physicochemical aging. The approach uses the application of various solid-state NMR techniques - including 1H and 13C NMR - to get a multitude of information on SOM. In non-rotating samples, 1H lines are usually very broad and unstructured. Nevertheless, this rather simple technique allows for a differentiation of 1H containing chemicals based on their dynamics in soil. This includes rather solid soil components and solid as well as mobile water molecules. Based on an optimized 1H solid-state NMR strategy to study soil material together with a straightforward lineshape analysis, a series of soils and peats are characterized. Although even 1H NMR with sample spinning (MAS) often gives only limited information on different structures, we present results on the application of 2D 1H-1H phase-modulated Lee-Goldburg sequences (PMLG), that show already at medium spinning speeds the separation of functional groups. Their quantification can be correlated with sample composition, type of sample conditioning, and other parameters such as cation type or concentration and heat treatment. We are especially interested to correlate NMR data with DSC measurements based on a certain heat treatment of the soils. Our proposed model describes the presence of water in soil as a matrix

  2. Crystal structure and tautomerism of Pigment Yellow 138 determined by X-ray powder diffraction and solid-state NMR

    DEFF Research Database (Denmark)

    Gumbert, Silke D.; Körbitzer, Meike; Alig, Edith

    2016-01-01

    The crystal structure of C.I. Pigment Yellow 138 was determined from X-ray powder diffraction data using real-space methods with subsequent Rietveld refinements. The tautomeric state was investigated by solid-state 1D and 2D multinuclear NMR experiments. In the crystals, the compound exhibits...... the NH-tautomer with a hydrogen atom situated at the nitrogen of the quinoline moiety. Direct evidence of the presence of the NH-tautomer is provided by 1H–14N HMQC solid-state NMR at very fast MAS. Solid-state dispersion-corrected density functional theory calculations with BLYP-D3 confirm...

  3. Hydronephrosis alters cardiac ACE2 and Mas receptor expression in mice.

    Science.gov (United States)

    Zhang, Yanling; Ma, Lulu; Wu, Junyan; Chen, Tingting

    2015-06-01

    Hydronephrosis is characterized by substantial loss of tubules and affects renin secretion in the kidney. However, whether alterations of angiotensin-converting enzyme (ACE), ACE2 and Mas receptor in the heart are observed in hydronephrosis is unknown. Thus, we assessed these components in hydronephrotic mice treated with AT1 receptor blockade and ACE inhibitor. Hydronephrosis was induced by left ureteral ligation in Balb/C mice except sham-operated animals. The levels of cardiac ACE, ACE2 and Mas receptor were measured after treatment of losartan or enalapril. Hydronephrosis led to an increase of ACE level and a decrease of ACE2 and Mas receptor in the heart. Losartan decreased cardiac ACE level, but ACE2 and Mas receptor levels significantly increased in hydronephrotic mice (p Hydronephrosis increased cardiac ACE and suppressed ACE2 and Mas receptor levels. AT1 blockade caused sustained activation of cardiac ACE2 and Mas receptor, but ACE inhibitor had the limitation of such activation of Mas receptor in hydronephrotic animals. © The Author(s) 2015.

  4. 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

  5. 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

  6. Quantitative dynamic nuclear polarization‐NMR on blood plasma for assays of drug metabolism

    DEFF Research Database (Denmark)

    Lerche, Mathilde Hauge; Meier, Sebastian; Jensen, Pernille Rose

    2011-01-01

    ‐scan 13C DNP‐NMR. An internal standard is used for the accurate quantification of drug and metabolite. Comparison of quantitative DNP‐NMR data with an established analytical method (liquid chromatography‐mass spectrometry) yields a Pearson correlation coefficient r of 0.99. Notably, all DNP...

  7. Can Memory Assessment Services (MAS) in England be categorized? A national survey.

    Science.gov (United States)

    Chrysanthaki, T; Fernandes, B; Smith, S; Black, N

    2017-12-01

    The effectiveness and efficiency of memory assessment services (MASs) is unknown. Our aim was to determine if a typology can be constructed, based on shared structural and process characteristics, as a basis for a non-randomized evaluation of their effectiveness and cost-effectiveness. Survey of random sample of 73 MASs in 2015; comparison of characteristics and investigation of inter-correlation. It was not possible to group characteristics to form the basis of a typology of MASs. However, there was considerable variation in staff numbers (20-fold), new patients per whole-time equivalent (WTE) staff (20-fold), skill mix and the nurse:doctor ratio (1-10). The operational performance also varied: first appointments (50-120 minutes); time for first follow-up (2-12 weeks); frequency of follow-up in first year (1-5). These differences were not associated with the number of new patients per WTE staff or the accreditation status of the MAS. Post diagnosis, all MASs provided pharmacological treatment but the availability of non-pharmacological support varied, with half providing none or only one intervention while others providing four or more. In the absence of any clear typology, evaluation of MASs will need to focus on the impact of individual structural and process characteristics on outcomes. © The Author 2017. Published by Oxford University Press on behalf of Faculty of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

  8. Flow units from integrated WFT and NMR data

    Energy Technology Data Exchange (ETDEWEB)

    Kasap, E.; Altunbay, M.; Georgi, D.

    1997-08-01

    Reliable and continuous permeability profiles are vital as both hard and soft data required for delineating reservoir architecture. They can improve the vertical resolution of seismic data, well-to-well stratigraphic correlations, and kriging between the well locations. In conditional simulations, permeability profiles are imposed as the conditioning data. Variograms, covariance functions and other geostatistical indicators are more reliable when based on good quality permeability data. Nuclear Magnetic Resonance (NMR) logging and Wireline Formation Tests (WFT) separately generate a wealth of information, and their synthesis extends the value of this information further by providing continuous and accurate permeability profiles without increasing the cost. NMR and WFT data present a unique combination because WFTs provide discrete, in situ permeability based on fluid-flow, whilst NMR responds to the fluids in the pore space and yields effective porosity, pore-size distribution, bound and moveable fluid saturations, and permeability. The NMR permeability is derived from the T{sub 2}-distribution data. Several equations have been proposed to transform T{sub 2} data to permeability. Regardless of the transform model used, the NMR-derived permeabilities depend on interpretation parameters that may be rock specific. The objective of this study is to integrate WFT permeabilities with NMR-derived, T{sub 2} distribution-based permeabilities and thereby arrive at core quality, continuously measured permeability profiles. We outlined the procedures to integrate NMR and WFT data and applied the procedure to a field case. Finally, this study advocates the use of hydraulic unit concepts to extend the WFT-NMR derived, core quality permeabilities to uncored intervals or uncored wells.

  9. 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.

  10. 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...

  11. 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

  12. Interaction study of polyisobutylene with paraffins by NMR using the evaluation of spin-lattice relaxation times for hydrogen nuclei

    International Nuclear Information System (INIS)

    Marques, Rosana G.G.; Tavares, Maria I.B.

    2001-01-01

    The evaluation of spin-lattice relaxation times of 1 H for polyisobutylene/paraffin systems, were obtained using the classic inversion recovery technique, and also through Cross Polarization Magic Angle Spinning (CP/MAS) techniques varying the contact time and also by the delayed contact time pulse sequence. NMR results showed that the polyisobutylene/paraffin systems in which high molecular weight paraffins were used, is heterogeneous. However, for paraffins with low molecular weight, the system presents good homogeneity. (author)

  13. Smoke, Clouds and Radiation Brazil NASA ER-2 Moderate Resolution Imaging Spectrometer (MODIS) Airborne Simulator (MAS) Data

    Data.gov (United States)

    National Aeronautics and Space Administration — SCARB_ER2_MAS data are Smoke, Clouds and Radiation Brazil (SCARB) NASA ER2 Moderate Resolution Imaging Spectrometer (MODIS) Airborne Simulator (MAS)...

  14. Chirp echo Fourier transform EPR-detected NMR.

    Science.gov (United States)

    Wili, Nino; Jeschke, Gunnar

    2018-04-01

    A new ultra-wide band (UWB) pulse EPR method is introduced for observing all nuclear frequencies of a paramagnetic center in a single shot. It is based on burning spectral holes with a high turning angle (HTA) pulse that excites forbidden transitions and subsequent detection of the hole pattern by a chirp echo. We term this method Chirp Echo Epr SpectroscopY (CHEESY)-detected NMR. The approach is a revival of FT EPR-detected NMR. It yields similar spectra and the same type of information as electron-electron double resonance (ELDOR)-detected NMR, but with a multiplex advantage. We apply CHEESY-detected NMR in Q band to nitroxides and correlate the hyperfine spectrum to the EPR spectrum by varying the frequency of the HTA pulse. Furthermore, a selective π pulse before the HTA pulse allows for detecting hyperfine sublevel correlations between transitions of one nucleus and for elucidating the coupling regime, the same information as revealed by the HYSCORE experiment. This is demonstrated on hexaaquamanganese(II). We expect that CHEESY-detected NMR is generally applicable to disordered systems and that our results further motivate the development of EPR spectrometers capable of coherent UWB excitation and detection, especially at higher fields and frequencies. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

  15. In situ viscosity of oil sands using low field NMR

    International Nuclear Information System (INIS)

    Bryan, J.; Moon, D.; Kantzas, A.

    2005-01-01

    In heavy oil and bitumen reservoirs, oil viscosity is a vital piece of information that will have great bearing on the chosen EOR scheme and the recovery expected. Prediction of in situ viscosity with a logging tool would he very beneficial in reservoir characterization and exploitation design. Low field NMR is a technology that has shown great potential as a tool for characterizing hydrocarbon properties in heavy oil and bitumen reservoirs. An oil viscosity correlation has previously been developed that is capable of providing order of magnitude viscosity estimates for a wide range of oils taken from various fields in Alberta. This paper presents tuning procedures to improve the NMR predictions for different viscosity ranges, and extends the NMR viscosity model to in situ heavy oil in unconsolidated sands. The results of this work show that the NMR oil peak can be de-convoluted from the in situ signals of the oil and water, and the bulk viscosity correlation that was developed for bulk oils can he applied to predict the in situ oil viscosity. These results can be translated to an NMR logging tool algorithm, allowing for in situ measurements of oil viscosity at the proper reservoir conditions. (author)

  16. Chirp echo Fourier transform EPR-detected NMR

    Science.gov (United States)

    Wili, Nino; Jeschke, Gunnar

    2018-04-01

    A new ultra-wide band (UWB) pulse EPR method is introduced for observing all nuclear frequencies of a paramagnetic center in a single shot. It is based on burning spectral holes with a high turning angle (HTA) pulse that excites forbidden transitions and subsequent detection of the hole pattern by a chirp echo. We term this method Chirp Echo Epr SpectroscopY (CHEESY)-detected NMR. The approach is a revival of FT EPR-detected NMR. It yields similar spectra and the same type of information as electron-electron double resonance (ELDOR)-detected NMR, but with a multiplex advantage. We apply CHEESY-detected NMR in Q band to nitroxides and correlate the hyperfine spectrum to the EPR spectrum by varying the frequency of the HTA pulse. Furthermore, a selective π pulse before the HTA pulse allows for detecting hyperfine sublevel correlations between transitions of one nucleus and for elucidating the coupling regime, the same information as revealed by the HYSCORE experiment. This is demonstrated on hexaaquamanganese(II). We expect that CHEESY-detected NMR is generally applicable to disordered systems and that our results further motivate the development of EPR spectrometers capable of coherent UWB excitation and detection, especially at higher fields and frequencies.

  17. 48 CFR 538.270 - Evaluation of multiple award schedule (MAS) offers.

    Science.gov (United States)

    2010-10-01

    ... SERVICES ADMINISTRATION SPECIAL CATEGORIES OF CONTRACTING FEDERAL SUPPLY SCHEDULE CONTRACTING Establishing and Administering Federal Supply Schedules 538.270 Evaluation of multiple award schedule (MAS) offers... determining the Government's price negotiation objectives, consider the following factors: (1) Aggregate...

  18. 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.

  19. 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...

  20. 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 ).

  1. 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 ).

  2. 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

  3. Microfabricated inserts for magic angle coil spinning (MACS wireless NMR spectroscopy.

    Directory of Open Access Journals (Sweden)

    Vlad Badilita

    Full Text Available This article describes the development and testing of the first automatically microfabricated probes to be used in conjunction with the magic angle coil spinning (MACS NMR technique. NMR spectroscopy is a versatile technique for a large range of applications, but its intrinsically low sensitivity poses significant difficulties in analyzing mass- and volume-limited samples. The combination of microfabrication technology and MACS addresses several well-known NMR issues in a concerted manner for the first time: (i reproducible wafer-scale fabrication of the first-in-kind on-chip LC microresonator for inductive coupling of the NMR signal and reliable exploitation of MACS capabilities; (ii improving the sensitivity and the spectral resolution by simultaneous spinning the detection microcoil together with the sample at the "magic angle" of 54.74° with respect to the direction of the magnetic field (magic angle spinning - MAS, accompanied by the wireless signal transmission between the microcoil and the primary circuit of the NMR spectrometer; (iii given the high spinning rates (tens of kHz involved in the MAS methodology, the microfabricated inserts exhibit a clear kinematic advantage over their previously demonstrated counterparts due to the inherent capability to produce small radius cylindrical geometries, thus tremendously reducing the mechanical stress and tearing forces on the sample. In order to demonstrate the versatility of the microfabrication technology, we have designed MACS probes for various Larmor frequencies (194, 500 and 700 MHz testing several samples such as water, Drosophila pupae, adamantane solid and LiCl at different magic angle spinning speeds.

  4. Dynamic Nuclear Polarization enhanced NMR at 187 GHz/284 MHz using an Extended Interaction Klystron amplifier.

    Science.gov (United States)

    Kemp, Thomas F; Dannatt, Hugh R W; Barrow, Nathan S; Watts, Anthony; Brown, Steven P; Newton, Mark E; Dupree, Ray

    2016-04-01

    A Dynamic Nuclear Polarisation (DNP) enhanced solid-state Magic Angle Spinning (MAS) NMR spectrometer which uses a 187 GHz (corresponding to (1)H NMR frequency of 284 MHz) Extended Interaction Klystron (EIK) amplifier as the microwave source is briefly described. Its performance is demonstrated for a biomolecule (bacteriorhodopsin), a pharmaceutical, and surface functionalised silica. The EIK is very compact and easily incorporated into an existing spectrometer. The bandwidth of the amplifier is sufficient that it obviates the need for a sweepable magnetic field, once set, for all commonly used radicals. The variable power (CW or pulsed) output from the EIK is transmitted to the DNP-NMR probe using a quasi-optic system with a high power isolator and a corrugated waveguide which feeds the microwaves into the DNP-NMR probe. Curved mirrors inside the probe project the microwaves down the axis of the MAS rotor, giving a very efficient system such that maximum DNP enhancement is achieved with less than 3 W output from the microwave source. The DNP-NMR probe operates with a sample temperature down to 90K whilst spinning at 8 kHz. Significant enhancements, in excess of 100 for bacteriorhodopsin in purple membrane (bR in PM), are shown along with spectra which are enhanced by ≈25 with respect to room temperature, for both the pharmaceutical furosemide and surface functionalised silica. These enhancements allow hitherto prohibitively time consuming experiments to be undertaken. The power at which the DNP enhancement in bR in PM saturates does not change significantly between 90K and 170 K even though the enhancement drops by a factor of ≈11. As the DNP build up time decreases by a factor 3 over this temperature range, the reduction in T1n is presumably a significant contribution to the drop in enhancement. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  5. MAS Integration and Controllership Effectiveness: Evidence of a Preparer-User Perception Gap

    OpenAIRE

    Weißenberger, Barbara E.; Angelkort, Hendrik; Holthoff, Gero

    2012-01-01

    Recent evidence suggests that managers establish a positive link between management accounting system (MAS) integration and controllership effectiveness, which is fully mediated by the perceived consistency of financial language. Our paper extends this research by analyzing whether controllers have similar perceptions on MAS design. Testing a series of multi-group structural equation models, we find evidence for a preparer-user perception gap with respect to the mediating impact of a consiste...

  6. 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.

  7. 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)

  8. 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

  9. 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.

  10. Perturbation of nuclear spin polarizations in solid state NMR of nitroxide-doped samples by magic-angle spinning without microwaves

    International Nuclear Information System (INIS)

    Thurber, Kent R.; Tycko, Robert

    2014-01-01

    We report solid state 13 C and 1 H nuclear magnetic resonance (NMR) experiments with magic-angle spinning (MAS) on frozen solutions containing nitroxide-based paramagnetic dopants that indicate significant perturbations of nuclear spin polarizations without microwave irradiation. At temperatures near 25 K, 1 H and cross-polarized 13 C NMR signals from 15 N, 13 C-labeled L-alanine in trinitroxide-doped glycerol/water are reduced by factors as large as six compared to signals from samples without nitroxide doping. Without MAS or at temperatures near 100 K, differences between signals with and without nitroxide doping are much smaller. We attribute most of the reduction of NMR signals under MAS near 25 K to nuclear spin depolarization through the cross-effect dynamic nuclear polarization mechanism, in which three-spin flips drive nuclear polarizations toward equilibrium with spin polarization differences between electron pairs. When T 1e is sufficiently long relative to the MAS rotation period, the distribution of electron spin polarization across the nitroxide electron paramagnetic resonance lineshape can be very different from the corresponding distribution in a static sample at thermal equilibrium, leading to the observed effects. We describe three-spin and 3000-spin calculations that qualitatively reproduce the experimental observations

  11. Perturbation of nuclear spin polarizations in solid state NMR of nitroxide-doped samples by magic-angle spinning without microwaves.

    Science.gov (United States)

    Thurber, Kent R; Tycko, Robert

    2014-05-14

    We report solid state (13)C and (1)H nuclear magnetic resonance (NMR) experiments with magic-angle spinning (MAS) on frozen solutions containing nitroxide-based paramagnetic dopants that indicate significant perturbations of nuclear spin polarizations without microwave irradiation. At temperatures near 25 K, (1)H and cross-polarized (13)C NMR signals from (15)N,(13)C-labeled L-alanine in trinitroxide-doped glycerol/water are reduced by factors as large as six compared to signals from samples without nitroxide doping. Without MAS or at temperatures near 100 K, differences between signals with and without nitroxide doping are much smaller. We attribute most of the reduction of NMR signals under MAS near 25 K to nuclear spin depolarization through the cross-effect dynamic nuclear polarization mechanism, in which three-spin flips drive nuclear polarizations toward equilibrium with spin polarization differences between electron pairs. When T1e is sufficiently long relative to the MAS rotation period, the distribution of electron spin polarization across the nitroxide electron paramagnetic resonance lineshape can be very different from the corresponding distribution in a static sample at thermal equilibrium, leading to the observed effects. We describe three-spin and 3000-spin calculations that qualitatively reproduce the experimental observations.

  12. Perturbation of nuclear spin polarizations in solid state NMR of nitroxide-doped samples by magic-angle spinning without microwaves

    Energy Technology Data Exchange (ETDEWEB)

    Thurber, Kent R., E-mail: thurberk@niddk.nih.gov; Tycko, Robert [Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520 (United States)

    2014-05-14

    We report solid state {sup 13}C and {sup 1}H nuclear magnetic resonance (NMR) experiments with magic-angle spinning (MAS) on frozen solutions containing nitroxide-based paramagnetic dopants that indicate significant perturbations of nuclear spin polarizations without microwave irradiation. At temperatures near 25 K, {sup 1}H and cross-polarized {sup 13}C NMR signals from {sup 15}N,{sup 13}C-labeled L-alanine in trinitroxide-doped glycerol/water are reduced by factors as large as six compared to signals from samples without nitroxide doping. Without MAS or at temperatures near 100 K, differences between signals with and without nitroxide doping are much smaller. We attribute most of the reduction of NMR signals under MAS near 25 K to nuclear spin depolarization through the cross-effect dynamic nuclear polarization mechanism, in which three-spin flips drive nuclear polarizations toward equilibrium with spin polarization differences between electron pairs. When T{sub 1e} is sufficiently long relative to the MAS rotation period, the distribution of electron spin polarization across the nitroxide electron paramagnetic resonance lineshape can be very different from the corresponding distribution in a static sample at thermal equilibrium, leading to the observed effects. We describe three-spin and 3000-spin calculations that qualitatively reproduce the experimental observations.

  13. Sine-squared shifted pulses for recoupling interactions in solid-state NMR

    Science.gov (United States)

    Jain, Mukul G.; Rajalakshmi, G.; Equbal, Asif; Mote, Kaustubh R.; Agarwal, Vipin; Madhu, P. K.

    2017-06-01

    Rotational-Echo DOuble-Resonance (REDOR) is a versatile experiment for measuring internuclear distance between two heteronuclear spins in solid-state NMR. At slow to intermediate magic-angle spinning (MAS) frequencies, the measurement of distances between strongly coupled spins is challenging due to rapid dephasing of magnetisation. This problem can be remedied by employing the pulse-shifted version of REDOR known as Shifted-REDOR (S-REDOR) that scales down the recoupled dipolar coupling. In this study, we propose a new variant of the REDOR sequence where the positions of the π pulses are determined by a sine-squared function. This new variant has scaling properties similar to S-REDOR. We use theory, numerical simulations, and experiments to compare the dipolar recoupling efficiencies and the experimental robustness of the three REDOR schemes. The proposed variant has advantages in terms of radiofrequency field requirements at fast MAS frequencies.

  14. 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.

  15. 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

  16. Whole-core analysis by 13C NMR

    International Nuclear Information System (INIS)

    Vinegar, H.J.; Tutunjian, P.N.; Edelstein, W.A.; Roemer, P.B.

    1991-01-01

    This paper reports on a whole-core nuclear magnetic resonance (NMR) system that was used to obtain natural abundance 13 C spectra. The system enables rapid, nondestructive measurements of bulk volume of movable oil, aliphatic/aromatic ratio, oil viscosity, and organic vs. carbonate carbon. 13 C NMR can be used in cores where the 1 H NMR spectrum is too broad to resolve oil and water resonances separately. A 5 1/4-in. 13 C/ 1 H NMR coil was installed on a General Electric (GE) CSI-2T NMR imager/spectrometer. With a 4-in.-OD whole core, good 13 C signal/noise ratio (SNR) is obtained within minutes, while 1 H spectra are obtained in seconds. NMR measurements have been made of the 13 C and 1 H density of crude oils with a wide range of API gravities. For light- and medium-gravity oils, the 13 C and 1 H signal per unit volume is constant within about 3.5%. For heavy crudes, the 13 C and 1 H density measured by NMR is reduced by the shortening of spin-spin relaxation time. 13 C and 1 H NMR spin-lattice relaxation times were measured on a suite of Cannon viscosity standards, crude oils (4 to 60 degrees API), and alkanes (C 5 through C 16 ) with viscosities at 77 degrees F ranging from 0.5 cp to 2.5 x 10 7 cp. The 13 C and 1 H relaxation times show a similar correlation with viscosity from which oil viscosity can be estimated accurately for viscosities up to 100 cp. The 13 C surface relaxation rate for oils on water-wet rocks is very low. Nonproton decoupled 13 C NMR is shown to be insensitive to kerogen; thus, 13 C NMR measures only the movable hydrocarbon content of the cores. In carbonates, the 13 C spectrum also contains a carbonate powder pattern useful in quantifying inorganic carbon and distinguishing organic from carbonate carbon

  17. 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

  18. Spectral editing at ultra-fast magic-angle-spinning in solid-state NMR: facilitating protein sequential signal assignment by HIGHLIGHT approach

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Songlin; Matsuda, Isamu; Long, Fei; Ishii, Yoshitaka, E-mail: yishii@uic.edu [University of Illinois at Chicago, Department of Chemistry (United States)

    2016-02-15

    This study demonstrates a novel spectral editing technique for protein solid-state NMR (SSNMR) to simplify the spectrum drastically and to reduce the ambiguity for protein main-chain signal assignments in fast magic-angle-spinning (MAS) conditions at a wide frequency range of 40–80 kHz. The approach termed HIGHLIGHT (Wang et al., in Chem Comm 51:15055–15058, 2015) combines the reverse {sup 13}C, {sup 15}N-isotope labeling strategy and selective signal quenching using the frequency-selective REDOR pulse sequence under fast MAS. The scheme allows one to selectively observe the signals of “highlighted” labeled amino-acid residues that precede or follow unlabeled residues through selectively quenching {sup 13}CO or {sup 15}N signals for a pair of consecutively labeled residues by recoupling {sup 13}CO–{sup 15}N dipolar couplings. Our numerical simulation results showed that the scheme yielded only ∼15 % loss of signals for the highlighted residues while quenching as much as ∼90 % of signals for non-highlighted residues. For lysine-reverse-labeled micro-crystalline GB1 protein, the 2D {sup 15}N/{sup 13}C{sub α} correlation and 2D {sup 13}C{sub α}/{sup 13}CO correlation SSNMR spectra by the HIGHLIGHT approach yielded signals only for six residues following and preceding the unlabeled lysine residues, respectively. The experimental dephasing curves agreed reasonably well with the corresponding simulation results for highlighted and quenched residues at spinning speeds of 40 and 60 kHz. The compatibility of the HIGHLIGHT approach with fast MAS allows for sensitivity enhancement by paramagnetic assisted data collection (PACC) and {sup 1}H detection. We also discuss how the HIGHLIGHT approach facilitates signal assignments using {sup 13}C-detected 3D SSNMR by demonstrating full sequential assignments of lysine-reverse-labeled micro-crystalline GB1 protein (∼300 nmol), for which data collection required only 11 h. The HIGHLIGHT approach offers valuable

  19. NMR of geophysical drill cores with a mobile Halbach scanner

    International Nuclear Information System (INIS)

    Talnishnikh, E.

    2007-01-01

    This thesis is devoted to a mobile NMR with an improved Halbach scanner. This is a lightweight tube-shaped magnet with sensitive volume larger and a homogeneity of the magnetic field higher than the previous prototype version. The improved Halbach scanner is used for analysis of water-saturated drill cores and plugs with diameters up to 60 mm. To provide the analysis, the standard 1D technique with the CPMG sequence as well as 2D correlation experiments were successfully applied and adapted to study properties of fluid-saturated sediments. Afterwards the Halbach scanner was calibrated to fast non-destructive measurements of porosity, relaxation time distributions, and estimation of permeability. These properties can be calculated directly from the NMR data using the developed methodology. Any independent measurements of these properties with other methods are not needed. One of the main results of this work is the development of a new NMR on-line core scanner for measurements of porosity in long cylindrical and semi cylindrical drill cores. Also dedicated software was written to operate the NMR on-line core scanner. The physical background of this work is the study of the diffusion influence on transverse relaxation. The diffusion effect in the presence of internal gradients in porous media was probed by 1D and 2D experiments. The transverse relaxation time distributions obtained from 1D and from 2D experiments are comparable but different in fine details. Two new methodologies were developed based on the results of this study. First is the methodology quantifying the influence of diffusion in the internal gradients of water-saturated sediments on transverse relaxation from 2D correlation experiments. The second one is the correction of the permeability estimation from the NMR data taking in account the influence of the diffusion. Furthermore, PFG NMR technique was used to study restricted diffusion in the same kind of samples. Preliminary results are reported

  20. NMR of geophysical drill cores with a mobile Halbach scanner

    Energy Technology Data Exchange (ETDEWEB)

    Talnishnikh, E.

    2007-08-21

    This thesis is devoted to a mobile NMR with an improved Halbach scanner. This is a lightweight tube-shaped magnet with sensitive volume larger and a homogeneity of the magnetic field higher than the previous prototype version. The improved Halbach scanner is used for analysis of water-saturated drill cores and plugs with diameters up to 60 mm. To provide the analysis, the standard 1D technique with the CPMG sequence as well as 2D correlation experiments were successfully applied and adapted to study properties of fluid-saturated sediments. Afterwards the Halbach scanner was calibrated to fast non-destructive measurements of porosity, relaxation time distributions, and estimation of permeability. These properties can be calculated directly from the NMR data using the developed methodology. Any independent measurements of these properties with other methods are not needed. One of the main results of this work is the development of a new NMR on-line core scanner for measurements of porosity in long cylindrical and semi cylindrical drill cores. Also dedicated software was written to operate the NMR on-line core scanner. The physical background of this work is the study of the diffusion influence on transverse relaxation. The diffusion effect in the presence of internal gradients in porous media was probed by 1D and 2D experiments. The transverse relaxation time distributions obtained from 1D and from 2D experiments are comparable but different in fine details. Two new methodologies were developed based on the results of this study. First is the methodology quantifying the influence of diffusion in the internal gradients of water-saturated sediments on transverse relaxation from 2D correlation experiments. The second one is the correction of the permeability estimation from the NMR data taking in account the influence of the diffusion. Furthermore, PFG NMR technique was used to study restricted diffusion in the same kind of samples. Preliminary results are reported

  1. Analysis of Hydroperoxides in solid Polyethylene by NMR and EPR Spectroscopy

    International Nuclear Information System (INIS)

    Assink, Roger A.; Celina, Mathias C.; Dunbar, Timothy D.; Alam, Todd M.; Clough, Roger Lee; Gillen, Kenneth T.

    2000-01-01

    The authors have shown that the hydroperoxide species in γ-irradiated 13 C-polyethylene can be directly observed by 13 C MAS NMR spectroscopy. The experiment was performed without the need for special sample preparation such as chemical derivatization or dissolution. Annealing experiments were employed to study the thermal decomposition of the hydroperoxide species and to measure an activation energy of 98 kJ/mol. EPR spectroscopy suggests that residual polyenyl and alkylperoxy radicals are predominantly trapped in interracial or crystalline regions, while the peroxy radicals observed after UV-photolysis of hydroperoxides are in amorphous regions

  2. Real time neutron diffraction and NMR of the Empress II glass-ceramic system.

    Science.gov (United States)

    O'Donnell, M D; Hill, R G; Karpukhina, N; Law, R V

    2011-10-01

    This study reports real time neutron diffraction on the Empress II glass-ceramic system. The commercial glass-ceramics was characterized by real time neutron diffraction, ³¹P and ²⁹Si solid-state MAS-NMR, DSC and XRD. On heating, the as-received glass ceramic contained lithium disilicate (Li₂Si₂O₅), which melted with increasing temperature. This was revealed by neutron diffraction which showed the Bragg peaks for this phase had disappeared by 958°C in agreement with thermal analysis. On cooling lithium metasilicate (Li₂SiO₃) started to form at around 916°C and a minor phase of cristobalite at around 852°C. The unit cell volume of both Li-silicate phases increased linearly with temperature at a rate of +17×10⁻³ ų.°C⁻¹. Room temperature powder X-ray diffraction (XRD) of the material after cooling confirms presence of the lithium metasilicate and cristobalite as the main phases and shows, in addition, small amount of lithium disilicate and orthophosphate. ³¹P MAS-NMR reveals presence of the lithiorthophosphate (Li₃PO₄) before and after heat treatment. The melting of lithium disilicate on heating and crystallisation of lithium metasilicate on cooling agree with endothermic and exotermic features respectively observed by DSC. ²⁹Si MAS-NMR shows presence of lithium disilicate phase in the as-received glass-ceramic, though not in the major proportion, and lithium metasilicate in the material after heat treatment. Both phases have significantly long T₁ relaxation time, especially the lithium metasilicate, therefore, a quantitative analysis of the ²⁹Si MAS-NMR spectra was not attempted. Significance. The findings of the present work demonstrate importance of the commercially designed processing parameters in order to preserve desired characteristics of the material. Processing the Empress II at a rate slower than recommended 60°C min⁻¹ or long isothermal hold at the maximal processing temperature 920°C can cause

  3. Neuroprotective Mechanisms of the ACE2-Angiotensin-(1-7)-Mas Axis in Stroke

    DEFF Research Database (Denmark)

    Bennion, Douglas M; Haltigan, Emily; Regenhardt, Robert W

    2015-01-01

    The discovery of beneficial neuroprotective effects of the angiotensin converting enzyme 2-angiotensin-(1-7)-Mas axis [ACE2-Ang-(1-7)-Mas] in ischemic and hemorrhagic stroke has spurred interest in a more complete characterization of its mechanisms of action. Here, we summarize findings that desc......The discovery of beneficial neuroprotective effects of the angiotensin converting enzyme 2-angiotensin-(1-7)-Mas axis [ACE2-Ang-(1-7)-Mas] in ischemic and hemorrhagic stroke has spurred interest in a more complete characterization of its mechanisms of action. Here, we summarize findings...... that describe the protective role of the ACE2-Ang-(1-7)-Mas axis in stroke, along with a focused discussion on the potential mechanisms of neuroprotective effects of Ang-(1-7) in stroke. The latter incorporates evidence describing the actions of Ang-(1-7) to counter the deleterious effects of angiotensin II...... complete understanding of the mechanisms of action of Ang-(1-7) to elicit neuroprotection will serve as an essential step toward research into potential targeted therapeutics in the clinical setting....

  4. 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.

  5. 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

  6. Facilitated assignment of large protein NMR signals with covariance sequential spectra using spectral derivatives.

    Science.gov (United States)

    Harden, Bradley J; Nichols, Scott R; Frueh, Dominique P

    2014-09-24

    Nuclear magnetic resonance (NMR) studies of larger proteins are hampered by difficulties in assigning NMR resonances. Human intervention is typically required to identify NMR signals in 3D spectra, and subsequent procedures depend on the accuracy of this so-called peak picking. We present a method that provides sequential connectivities through correlation maps constructed with covariance NMR, bypassing the need for preliminary peak picking. We introduce two novel techniques to minimize false correlations and merge the information from all original 3D spectra. First, we take spectral derivatives prior to performing covariance to emphasize coincident peak maxima. Second, we multiply covariance maps calculated with different 3D spectra to destroy erroneous sequential correlations. The maps are easy to use and can readily be generated from conventional triple-resonance experiments. Advantages of the method are demonstrated on a 37 kDa nonribosomal peptide synthetase domain subject to spectral overlap.

  7. Escala de atitudes frente ao dinheiro (MAS: Teste de modelos e poder preditivo

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Pimentel

    2012-01-01

    Full Text Available The social importance attached to money and its role as an important motivator of behavior justifies the study of its psychosocial aspects. But there is a lack of studies concerning attitudinal or psychological aspects of money in Brazil. In order to encourage research in this context, the validity of the Money Attitudes Scale (MAS was tested using confirmatory factor approaches. Results supported a brief 16-items version of the scale and replicated the factor analytic pattern with satisfactory internal consistency for the factors of power, retention, distrust, and anxiety. Age differences were observed regarding money attitudes of power, and the predictive role of the MAS to account for consumer behavior was also confirmed. This version of the MAS shows evidences of factorial validity and reliability, justifying its use in future research.

  8. SIMPSON: A general simulation program for solid-state NMR spectroscopy

    Science.gov (United States)

    Bak, Mads; Rasmussen, Jimmy T.; Nielsen, Niels Chr.

    2011-12-01

    A computer program for fast and accurate numerical simulation of solid-state NMR experiments is described. The program is designed to emulate a NMR spectrometer by letting the user specify high-level NMR concepts such as spin systems, nuclear spin interactions, RF irradiation, free precession, phase cycling, coherence-order filtering, and implicit/explicit acquisition. These elements are implemented using the Tel scripting language to ensure a minimum of programming overhead and direct interpretation without the need for compilation, while maintaining the flexibility of a full-featured programming language. Basicly, there are no intrinsic limitations to the number of spins, types of interactions, sample conditions (static or spinning, powders, uniaxially oriented molecules, single crystals, or solutions), and the complexity or number of spectral dimensions for the pulse sequence. The applicability ranges from simple ID experiments to advanced multiple-pulse and multiple-dimensional experiments, series of simulations, parameter scans, complex data manipulation/visualization, and iterative fitting of simulated to experimental spectra. A major effort has been devoted to optimizing the computation speed using state-of-the-art algorithms for the time-consuming parts of the calculations implemented in the core of the program using the C programming language. Modification and maintenance of the program are facilitated by releasing the program as open source software (General Public License) currently at http://nmr.imsb.au.dk. The general features of the program are demonstrated by numerical simulations of various aspects for REDOR, rotational resonance, DRAMA, DRAWS, HORROR, C7, TEDOR, POST-C7, CW decoupling, TPPM, F-SLG, SLF, SEMA-CP, PISEMA, RFDR, QCPMG-MAS, and MQ-MAS experiments.

  9. 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...

  10. Covariance NMR Processing and Analysis for Protein Assignment.

    Science.gov (United States)

    Harden, Bradley J; Frueh, Dominique P

    2018-01-01

    During NMR resonance assignment it is often necessary to relate nuclei to one another indirectly, through their common correlations to other nuclei. Covariance NMR has emerged as a powerful technique to correlate such nuclei without relying on error-prone peak peaking. However, false-positive artifacts in covariance spectra have impeded a general application to proteins. We recently introduced pre- and postprocessing steps to reduce the prevalence of artifacts in covariance spectra, allowing for the calculation of a variety of 4D covariance maps obtained from diverse combinations of pairs of 3D spectra, and we have employed them to assign backbone and sidechain resonances in two large and challenging proteins. In this chapter, we present a detailed protocol describing how to (1) properly prepare existing 3D spectra for covariance, (2) understand and apply our processing script, and (3) navigate and interpret the resulting 4D spectra. We also provide solutions to a number of errors that may occur when using our script, and we offer practical advice when assigning difficult signals. We believe such 4D spectra, and covariance NMR in general, can play an integral role in the assignment of NMR signals.

  11. Development of a generic, computerized nuclear material accountability system: NucMAS

    International Nuclear Information System (INIS)

    Cornell, M.D.; O'Leary, J.M.

    1987-01-01

    The application NucMAS provides basic computerized accountability functions for the Savannah River Plant (SRP) Separations Department Material Balance Areas (MBA's). These functions include data entry, data management, calculations, and report generation. NucMAS can be used both for routine reporting to the SRP central Material Control and Accounting (MC and A) system and for rapid ad hoc queries in emergency situations. The system is designed to work with any process handling one or more of the 17 accountable nuclear materials specified by the Department of Energy (DOE). It relies on user-supplied configuration data to drive data prompts, report headings, data validations, and calculations

  12. Structure resolution of Ba5Al3F19 and Iivestigation of fluorine ion dynamics by synchrotron powder diffraction, variable-temperature solid-state NMR, and quantum computations

    International Nuclear Information System (INIS)

    Martineau, C.; Fayon, F.; Suchomel, M.R.; Allix, M.; Massiot, D.; Taulelle, F.

    2011-01-01

    The room temperature structure of Ba 5 Al 3 F 19 has been solved using electron microscopy and synchrotron powder diffraction data. One-dimensional (1D) 27 Al and ultrafast magic-angle-spinning (MAS) 19 F NMR spectra have been recorded and are in agreement with the proposed structural model for Ba 5 Al 3 F 19 . The 19 F isotropic chemical shift and 27 Al quadrupolar parameters have been calculated using the CASTEP code from the experimental and density functional theory geometry-optimized structures. After optimization, the calculated NMR parameters of both the 19 F and 27 Al nuclei show improved consistency with the experimental values, demonstrating that the geometry optimization step is necessary to obtain more accurate and reliable structural data. This also enables a complete and unambiguous assignment of the 19 F MAS NMR spectrum of Ba 5 Al 3 F 19 . Variable-temperature 1D MAS 19 F NMR experiments have been carried out, showing the occurrence of fluorine ion mobility. Complementary insights were obtained from both two-dimensional (2D) exchange and 2D double-quantum dipolar recoupling NMR experiments, and a detailed analysis of the anionic motion in Ba 5 Al 3 F 19 is proposed, including the distinction between reorientational processes and chemical exchange involving bond breaking and re-formation.

  13. Characterization of new materials in chromatography and fuel cell development by modern NMR techniques; Charakterisierung neuer Materialien in der Chromatographie und Brennstoffzellen-Forschung mit Hilfe moderner NMR-Techniken

    Energy Technology Data Exchange (ETDEWEB)

    Schauff, S.

    2007-12-28

    New materials, suitable for the application in reversed phase liquid chromatography and fuel cell membranes, were characterized regarding their structure and dynamic properties using solid-state and suspended-state NMR spectroscopy. Both methods were found to be suitable to study the dynamic behaviour, the first to observe intrinsic mobilities of phosphonic acids, the second to monitor interaction processes taking place in a chromatography-like system. Several phosphonic acids, which are promising materials for high temperature fuel cell membranes, were investigated with respect to proton mobility and transport applying various solid-state NMR methods. In addition, water uptake and its effects on anhydride formation were studied on samples that were equilibrated with saturated salt solutions. For PVPA substantial, reversible anhydride formation was found, while MePA did not show condensation. These results show that the relation between hydrogen bond strength and proton mobility is complex. In particular, this work demonstrates that the application of simple 1D 1H and 2H NMR experiments provides easy access to information about proton/deuteron mobility on short time scales, needed for an identification of materials with high intrinsic proton conductivities. Stationary phases for reversed phase liquid chomatography were characterized by solid-state NMR spectroscopy, and their influence on different analytes was studied using suspendedstate HR-MAS NMR spectroscopy. Suspended-state HR-MAS NMR spectroscopy showed to be suitable to model the separation process of analytes on chromatographic sorbents. For this, the stationary phase was suspended in a solution of analyte dissolved in mobile phase. MePhSucc showed a peak doubling of the CH2 group in presence of monomeric C18 phase, leading to the coexistence of a narrow and a broadened peak. Thus, the dynamic interactions of MePhSucc towards the stationary phase, and under the influence of the mobile phase, could be

  14. 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

  15. The xGa{sub 2}O{sub 3}–(100 − x)NaPO{sub 3} glass system: Preparation, properties and structural analysis by solid state NMR

    Energy Technology Data Exchange (ETDEWEB)

    Caron, A. [UCCS UMR-CNRS 8181, Université de Lille1, Villeneuve d' Ascq (France); Doumert, B. [IMMCL, Université de Lille1, Villeneuve d' Ascq (France); Tricot, G., E-mail: gregory.tricot@univ-lille1.fr [UCCS UMR-CNRS 8181, Université de Lille1, Villeneuve d' Ascq (France); LASIR UMR-CNRS 8516, Université de Lille1, Villeneuve d' Ascq (France)

    2014-10-15

    Insertion of Ga{sub 2}O{sub 3} in sodium metaphosphate glasses has been investigated in this paper. Materials containing up to 30 mol% of Ga{sub 2}O{sub 3} have been prepared using the standard melt-quenching technique within the xGa{sub 2}O{sub 3}–(100 − x)NaPO{sub 3} composition line. Macroscopic properties (glass transition temperature, density and molar volume) are significantly affected by the Ga{sub 2}O{sub 3} insertion. 1D {sup 71}Ga and {sup 31}P magic angle spinning nuclear magnetic resonance (MAS-NMR) performed at very high field (18.8 T) indicate a strong evolution of the gallium coordination state around the x = 15 composition and a continuous evolution of the phosphate network organisation. In addition, {sup 71}Ga({sup 31}P) D-HMQC NMR technique was used for the first time to highlight the presence of mixed P–O–Ga linkages within the glass structure. The impact of gallium insertion is finally discussed and compared to the effect of the widely used aluminum and boron elements. If gallium and aluminum elements present similar effect on the macroscopic properties, some discrepancies can be observed concerning their structural effect. - Highlights: • Glasses with 30 mol% of Ga{sub 2}O{sub 3} have been prepared in the NaPO{sub 3}–Ga{sub 2}O{sub 3} line. • T{sub g} and density are affected by the Ga{sup 3+} insertion. • Presence of mixed Ga/P species have been highlighted by 2D correlation NMR.

  16. 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.

  17. 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.

  18. Measurement of backbone hydrogen-deuterium exchange in the type III secretion system needle protein PrgI by solid-state NMR

    Science.gov (United States)

    Chevelkov, Veniamin; Giller, Karin; Becker, Stefan; Lange, Adam

    2017-10-01

    In this report we present site-specific measurements of amide hydrogen-deuterium exchange rates in a protein in the solid state phase by MAS NMR. Employing perdeuteration, proton detection and a high external magnetic field we could adopt the highly efficient Relax-EXSY protocol previously developed for liquid state NMR. According to this method, we measured the contribution of hydrogen exchange on apparent 15N longitudinal relaxation rates in samples with differing D2O buffer content. Differences in the apparent T1 times allowed us to derive exchange rates for multiple residues in the type III secretion system needle protein.

  19. MetAssimulo:Simulation of Realistic NMR Metabolic Profiles

    Directory of Open Access Journals (Sweden)

    De Iorio Maria

    2010-10-01

    Full Text Available Abstract Background Probing the complex fusion of genetic and environmental interactions, metabolic profiling (or metabolomics/metabonomics, the study of small molecules involved in metabolic reactions, is a rapidly expanding 'omics' field. A major technique for capturing metabolite data is 1H-NMR spectroscopy and this yields highly complex profiles that require sophisticated statistical analysis methods. However, experimental data is difficult to control and expensive to obtain. Thus data simulation is a productive route to aid algorithm development. Results MetAssimulo is a MATLAB-based package that has been developed to simulate 1H-NMR spectra of complex mixtures such as metabolic profiles. Drawing data from a metabolite standard spectral database in conjunction with concentration information input by the user or constructed automatically from the Human Metabolome Database, MetAssimulo is able to create realistic metabolic profiles containing large numbers of metabolites with a range of user-defined properties. Current features include the simulation of two groups ('case' and 'control' specified by means and standard deviations of concentrations for each metabolite. The software enables addition of spectral noise with a realistic autocorrelation structure at user controllable levels. A crucial feature of the algorithm is its ability to simulate both intra- and inter-metabolite correlations, the analysis of which is fundamental to many techniques in the field. Further, MetAssimulo is able to simulate shifts in NMR peak positions that result from matrix effects such as pH differences which are often observed in metabolic NMR spectra and pose serious challenges for statistical algorithms. Conclusions No other software is currently able to simulate NMR metabolic profiles with such complexity and flexibility. This paper describes the algorithm behind MetAssimulo and demonstrates how it can be used to simulate realistic NMR metabolic profiles with

  20. A High-Resolution Magic Angle Spinning NMR Study of the Enantiodiscrimination of 3,4-Methylenedioxymethamphetamine (MDMA by an Immobilized Polysaccharide-Based Chiral Phase.

    Directory of Open Access Journals (Sweden)

    Juliana C Barreiro

    Full Text Available This paper reports the investigation of the chiral interaction between 3,4-methylenedioxy-methamphetamine (MDMA enantiomers and an immobilized polysaccharide-based chiral phase. For that, suspended-state high-resolution magic angle spinning nuclear magnetic resonance spectroscopy (1H HR-MAS NMR was used. 1H HR-MAS longitudinal relaxation time and Saturation Transfer Difference (STD NMR titration experiments were carried out yielding information at the molecular level of the transient diastereoisomeric complexes of MDMA enantiomers and the chiral stationary phase. The interaction of the enantiomers takes place through the aromatic moiety of MDMA and the aromatic group of the chiral selector by π-π stacking for both enantiomers; however, a stronger interaction was observed for the (R-enantiomer, which is the second one to elute at the chromatographic conditions.

  1. 1H High Resolution Magic-Angle Coil Spinning (HR-MACS µNMR Metabolic Profiling of whole Saccharomyces cervisiae cells: A Demonstrative Study

    Directory of Open Access Journals (Sweden)

    Alan eWong

    2014-06-01

    Full Text Available The low sensitivity of Nuclear Magnetic Resonance (NMR is its prime shortcoming compared to other analytical methods for metabolomic studies. It relies on large sample volume (30–50 µl for HR-MAS for rich metabolic profiling, hindering high-throughput screening especially when the sample requires a labor-intensive preparation or is a sacred specimen. This is indeed the case for some living organisms. This study evaluates a 1H HR-MAS approach for metabolic profiling of small volume (250 nl whole bacterial cells, Saccharomyces cervisiae, using an emerging micro-NMR technology: high-resolution magic-angle coil spinning (HR-MACS. As a demonstrative study for whole cells, we perform two independent metabolomics studies identifying the significant metabolites associated with osmotic stress and aging.

  2. Who bears the burden of international taxation? Evidence from cross-border M&As

    NARCIS (Netherlands)

    Huizinga, H.P.; Voget, J.; Wagner, W.B.

    2012-01-01

    Cross-border M&As can trigger additional taxation of the target's income in the form of non-resident dividend withholding taxes and acquirer-country corporate income taxation. This paper finds that this additional international taxation is fully capitalized into lower takeover premiums. In contrast,

  3. Acceptance Test Report for the Modular Automation System (MAS) Manufactured by Honeywell Inc

    International Nuclear Information System (INIS)

    ANDERSON, D.L.

    2000-01-01

    This document details the performance of the acceptance test of the Honeywell MAS Control System for equipment to be installed in gloveboxes HA-20MB and HA-211 at a later date. Equipment that was anticipated included 6 stabilization furnaces, only three and their associated equipment were installed

  4. SecMAS: Security Enhanced Monitoring and Analysis Systems for Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Ding Chao

    2016-01-01

    Full Text Available The monitoring, control, and security guarantee for the communication in the wireless sensor networks (WSNs are currently treated as three independent issues and addressed separately through specialized tools. However, most cases of WSNs applications requires the network administrator change the network configuration in a very short time to response to the change of observed phenomenon with security guarantee. To meet this requirement, we propose a security enhanced monitoring and control platform named SecMAS for WSNs, which provides the real-time visualization about network states and online reconfiguration of the network properties and behaviours in a resource-efficient way. Besides, basic cryptographic primitives and part of the anomaly detection functionalities are implemented in SecMAS to enabling the secure communication in WSNs. Furthermore, we conduct experiments to evaluate the performance of SecMAS in terms of the latency, throughput, communication overhead, and the security capacity. The experimental results demonstrate that the SecMAS system achieves stable, efficient and secure data collection with lightweight quick-response network control.

  5. Characterization and significance of ACE2 and Mas receptor in human colon adenocarcinoma.

    Science.gov (United States)

    Bernardi, Stella; Zennaro, Cristina; Palmisano, Silvia; Velkoska, Elena; Sabato, Nicoletta; Toffoli, Barbara; Giacomel, Greta; Buri, Luigi; Zanconati, Fabrizio; Bellini, Giuseppe; Burrell, Louise M; De Manzini, Nicolò; Fabris, Bruno

    2012-03-01

    A new arm of the renin-angiotensin system (RAS) has been recently characterized; this includes angiotensin converting enzyme (ACE)2 and angiotensin (Ang)1-7, a heptapeptide acting through the Mas receptor (MasR). Recent studies show that Ang1-7 has an antiproliferative action on lung adenocarcinoma cells. The aim of this study was to characterize RAS expression in human colon adenocarcinoma and to investigate whether Ang1-7 exerts an antiproliferative effect on human colon adenocarcinoma cells. Gene, protein expression and enzymatic activity of the main components of the RAS were determined on non-neoplastic colon mucosa as well as on the tumor mass and the mucosa taken 5 cm distant from it, both collected from patients with colon adenocarcinoma. Two different human colon cancer cell lines were treated with AngII and Ang1-7. The novel finding of this study was that MasR was significantly upregulated in colon adenocarcinoma compared with non-neoplastic colon mucosa, which showed little or no expression of it. ACE gene expression and enzymatic activity were also increased in the tumors. However, AngII and Ang1-7 did not have any pro-/antiproliferative effects in the cell lines studied. The data suggest that upregulation of the MasR could be used as a diagnostic marker of colon adenocarcinoma.

  6. 77 FR 43084 - Multiple Award Schedule (MAS) Program Continuous Open Season-Operational Change

    Science.gov (United States)

    2012-07-23

    ... (GSA), Federal Acquisition Service (FAS) intends to institute a Demand Based Model (DBM) designed to... will restore and maintain the MAS program's value to Federal agencies as a streamlined acquisition... adding innovative solutions, improving pricing and simplifying the buying experience. DATES: This change...

  7. An Analysis of the Rise and Fall of the AA-MAS Policy

    Science.gov (United States)

    Lazarus, Sheryl S.; Thurlow, Martha L.; Ysseldyke, James E.; Edwards, Lynn M.

    2015-01-01

    In 2005, to address concerns about students who might fall in the "gap" between the regular assessment and the alternate assessment based on alternate achievement standards (AA-AAS), the U.S. Department of Education announced that states could develop alternate assessments based on modified achievement standards (AA-MAS). This article…

  8. Considerations for Consortia as States Transition Away from AA-MAS. NCEO Brief. Number 7

    Science.gov (United States)

    National Center on Educational Outcomes, 2014

    2014-01-01

    States with an alternate assessment based on modified achievement standards (AA-MAS) that received a flexibility waiver from some of the requirements of No Child Left Behind are required to phase out their use of this assessment. And, on August 23, 2013, the U.S. Department of Education published a proposed rollback of regulation that allowed the…

  9. Successfully Transitioning from the AA-MAS to the General Assessment. NCEO Policy Directions. Number 22

    Science.gov (United States)

    Lazarus, Sheryl; Thurlow, Martha; Christensen, Laurene; Shyyan, Vitaliy

    2014-01-01

    Federal policy initiatives such as the flexibility waivers for accountability are requiring that states transition away from the use of an alternate assessment based on modified achievement standards (AA-MAS). It is expected that those students who had participated in that assessment will instead participate in the state's general assessment (or a…

  10. Marker-assisted-selection (MAS): A fast track to increase genetic ...

    African Journals Online (AJOL)

    Mapping and tagging of agriculturally important genes have been greatly facilitated by an array of molecular markers in crop plants. Marker-assisted selection (MAS) is gaining considerable importance as it would improve the efficiency of plant breeding through precise transfer of genomic regions of interest (foreground ...

  11. Two-Stage MAS Technique for Analysis of DRA Elements and Arrays on Finite Ground Planes

    DEFF Research Database (Denmark)

    Larsen, Niels Vesterdal; Breinbjerg, Olav

    2007-01-01

    A two-stage Method of Auxiliary Sources (MAS) technique is proposed for analysis of dielectric resonator antenna (DRA) elements and arrays on finite ground planes (FGPs). The problem is solved by first analysing the DRA on an infinite ground plane (IGP) and then using this solution to model the FGP...

  12. Optimal degree of protonation for {sup 1}H detection of aliphatic sites in randomly deuterated proteins as a function of the MAS frequency

    Energy Technology Data Exchange (ETDEWEB)

    Asami, Sam [Helmholtz-Zentrum Muenchen (HMGU), Deutsches Forschungszentrum fuer Gesundheit und Umwelt (HMGU) (Germany); Szekely, Kathrin; Schanda, Paul; Meier, Beat H. [Eidgenoessische Technische Hochschule Zuerich (ETH Zuerich) (Switzerland); Reif, Bernd, E-mail: reif@tum.de [Helmholtz-Zentrum Muenchen (HMGU), Deutsches Forschungszentrum fuer Gesundheit und Umwelt (HMGU) (Germany)

    2012-10-15

    The {sup 1}H dipolar network, which is the major obstacle for applying proton detection in the solid-state, can be reduced by deuteration, employing the RAP (Reduced Adjoining Protonation) labeling scheme, which yields random protonation at non-exchangeable sites. We present here a systematic study on the optimal degree of random sidechain protonation in RAP samples as a function of the MAS (magic angle spinning) frequency. In particular, we compare {sup 1}H sensitivity and linewidth of a microcrystalline protein, the SH3 domain of chicken {alpha}-spectrin, for samples, prepared with 5-25 % H{sub 2}O in the E. coli growth medium, in the MAS frequency range of 20-60 kHz. At an external field of 19.96 T (850 MHz), we find that using a proton concentration between 15 and 25 % in the M9 medium yields the best compromise in terms of sensitivity and resolution, with an achievable average {sup 1}H linewidth on the order of 40-50 Hz. Comparing sensitivities at a MAS frequency of 60 versus 20 kHz, a gain in sensitivity by a factor of 4-4.5 is observed in INEPT-based {sup 1}H detected 1D {sup 1}H,{sup 13}C correlation experiments. In total, we find that spectra recorded with a 1.3 mm rotor at 60 kHz have almost the same sensitivity as spectra recorded with a fully packed 3.2 mm rotor at 20 kHz, even though {approx}20 Multiplication-Sign less material is employed. The improved sensitivity is attributed to {sup 1}H line narrowing due to fast MAS and to the increased efficiency of the 1.3 mm coil.

  13. HUBUNGAN ANTARA PERTUMBUHAN DENGAN KEBERADAAN GEN TAHAN PENYAKIT MAJOR HISTOCOMPATIBILITY COMPLEX (MHC PADA IKAN MAS (Cyprinus carpio

    Directory of Open Access Journals (Sweden)

    Erma Primanita Hayuningtyas

    2016-04-01

    Full Text Available Wabah penyakit koi herpes virus (KHV di Indonesia yang terjadi sejak tahun 2002 merupakan salah satu faktor yang memicu kemerosotan produksi ikan mas budidaya. Pembentukan strain unggul ikan mas tahan KHV dapat menjadi solusi bagi permasalahan tersebut. Pemilihan genotip ikan mas tahan KHV dengan marka molekuler gen major histocompatibility complex class II (MHC-II, khususnya pada alel Cyca DAB 1*05 akan membantu dalam kegiatan seleksi. Penelitian ini bertujuan untuk mengetahui keberadaan gen MHC-II pada populasi dasar G0 ikan mas strain Rajadanu dan hubungannya dengan pertumbuhan (bobot. Metode deteksi keberadaan gen MHC-II pada dua kelompok ikan dengan ukuran berbeda dilakukan dengan teknik PCR. Hubungan antara pertumbuhan ikan mas dengan persentase kemunculan gen MHC-II dianalisis dengan menggunakan program SPSS (Statistical Package for the Social Sciences, sehingga diperoleh korelasi di antara keduanya. Hasil penelitian menunjukkan bahwa hubungan antara pertumbuhan dengan persentase keberadaan gen MHC-II berkorelasi negatif dengan nilai R = -0,742. Hal ini mengindikasikan bahwa semakin cepat pertumbuhan populasi ikan mas maka semakin sedikit persentase individu yang mempunyai gen MHC-II pada setiap populasi ikan mas. Sehingga populasi ikan mas yang pertumbuhannya lambat memiliki tingkat persentase positif MHC-II lebih tinggi (85,71%-100% dibandingkan populasi ikan mas yang pertumbuhannya cepat (42,86%-85,71%.

  14. Group Chemical Changes and Physical Property Correlations in Refining of Lube Base Stocks. Ir and Nmr Spectroscopy Corrélations entre les propriétés physiques et les changements de composition chimique au cours du raffinage des huiles de base. Spectrométrie infra rouge et résonance magnétique nucléaire

    Directory of Open Access Journals (Sweden)

    Singh H.

    2006-11-01

    Full Text Available Changes occurring in the chemical composition of lubricating oil base stocks with different degreeand typeof refining have been investigated by IR and NMR spectroscopy. Significant conclusions about the chemical composition have been reached through the study of structural parameters. Correlations between molecular parameters such as aromaticity , average number of carbon atoms per alkyl substituentand the Viscosity Indexof base oils are reported. The term degree of refininghas been assigned a quantitative value in combination with the VI to denote the progressive refining of raw lube distillates to base stocks. Les modifications de la composition chimique d'huiles lubrifiantes au cours de divers type de raffinage à des degrés variables de sévérité sont étudiées par spectrométries IR et RMN. L'étude des paramètres structuraux aboutit à des conclusions significatives sur la composition chimique. Des corrélations entre l'indice de viscosité et des paramètres structuraux tels que l'aromaticité et le nombre moyen d'atomes de carbone par substituant alkyl sont dégagées. On attribue au terme degré de raffinage une valeur quantitative - combiné avec l'indice de viscosité pour signifier le raffinage progressif de distillats bruts en huiles de base.

  15. Aluminum siting in silicon-rich zeolite frameworks: A combined high-resolution Al-27 NMR spectroscopy and quantum mechanics/molecular mechanics study of ZSM-5

    Czech Academy of Sciences Publication Activity Database

    Sklenák, Štěpán; Dědeček, Jiří; Li, Chengbin; Wichterlová, Blanka; Gábová, Vendula; Sierka, M.; Sauer, J.

    2007-01-01

    Roč. 46, č. 38 (2007), s. 7286-7289 ISSN 1433-7851 R&D Projects: GA AV ČR 1ET400400413; GA ČR GA203/06/1449; GA AV ČR IAA4040308 Institutional research plan: CEZ:AV0Z40400503 Keywords : MQ MAS NMR * chemical-shifts * ab-initio * catalysts Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 10.031, year: 2007

  16. Further conventions for NMR shielding and chemical shifts (IUPAC Recommendations 2008)

    Energy Technology Data Exchange (ETDEWEB)

    Harris, R.K. [University of Durham, Durham (United Kingdom). Dept. of Chemistry; Becker, E.D. [National Institutes of Health, Bethesda, MD (United States); Menezes, S.M. Cabral de [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES); Granger, P. [University Louis Pasteur, Strasbourg (France). Inst. of Chemistry; Hoffman, R.E. [The Hebrew University of Jerusalem, Safra Campus, Jerusalem (Israel). Dept. of Organic Chemistry; Zilm, K.W., E-mail: r.k.harris@durham.ac.uk [Yale University, New Haven, CT (United States). Dept. of Chemistry

    2008-07-01

    IUPAC has published a number of recommendations regarding the reporting of nuclear magnetic resonance (NMR) data, especially chemical shifts. The most recent publication [Pure Appl. Chem. 73, 1795 (2001)] recommended that tetramethylsilane (TMS) serve as a universal reference for reporting the shifts of all nuclides, but it deferred recommendations for several aspects of this subject. This document first examines the extent to which the {sup 1}H shielding in TMS itself is subject to change by variation in temperature, concentration, and solvent. On the basis of recently published results, it has been established that the shielding of TMS in solution [along with that of sodium-3- (trimethylsilyl)propanesulfonate, DSS, often used as a reference for aqueous solutions] varies only slightly with temperature but is subject to solvent perturbations of a few tenths of a part per million (ppm). Recommendations are given for reporting chemical shifts under most routine experimental conditions and for quantifying effects of temperature and solvent variation, including the use of magnetic susceptibility corrections and of magic-angle spinning (MAS). This document provides the first IUPAC recommendations for referencing and reporting chemical shifts in solids, based on high-resolution MAS studies. Procedures are given for relating {sup 13}C NMR chemical shifts in solids to the scales used for high resolution studies in the liquid phase. The notation and terminology used for describing chemical shift and shielding tensors in solids are reviewed in some detail, and recommendations are given for best practice. (author)

  17. DRAMAtic transforms in magic angle spinning recoupling NMR: The Bessel function pathway.

    Science.gov (United States)

    Goodman, Russell; Hancock, Jason; Siemens, Mark; Jarrell, Harold; Siminovitch, David

    2005-07-01

    In magic angle spinning (MAS) NMR recoupling experiments, the extraction of multiple couplings or a coupling distribution from the observed dephasing signals remains a challenging problem. At least for REDOR experiments, the REDOR transform solves this problem, enabling the simultaneous measurement of multiple dipolar couplings. Focusing on the quadrupolar dephasing observed in QUADRAMA experiments as a representative example, we demonstrate that the same analytical form used for the mathematical description of REDOR dephasing also describes the dephasing observed in a wide variety of MAS NMR recoupling experiments. This fact immediately extends REDOR transform techniques to a much broader suite of recoupling experiments than had previously been realized, including those of DRAMA, MELODRAMA and QUADRAMA. As an illustration, we use the DRAMAtic transform to provide the first inversion of a QUADRAMA dephasing signal to extract the quadrupole coupling distribution. Using a complete elliptic integral of the first kind, we further develop a novel expression for the Pake-spun powder patterns of the corresponding recoupled lineshapes. Our methods and results reinforce the central role that Bessel functions can play in simplifying the integrals that define both the dephasing signals in the time domain, and their Fourier transforms in the frequency domain.

  18. Further conventions for NMR shielding and chemical shifts (IUPAC Recommendations 2008)

    International Nuclear Information System (INIS)

    Harris, R.K.; Menezes, S.M. Cabral de; Granger, P.; Hoffman, R.E.; Zilm, K.W.

    2008-01-01

    IUPAC has published a number of recommendations regarding the reporting of nuclear magnetic resonance (NMR) data, especially chemical shifts. The most recent publication [Pure Appl. Chem. 73, 1795 (2001)] recommended that tetramethylsilane (TMS) serve as a universal reference for reporting the shifts of all nuclides, but it deferred recommendations for several aspects of this subject. This document first examines the extent to which the 1 H shielding in TMS itself is subject to change by variation in temperature, concentration, and solvent. On the basis of recently published results, it has been established that the shielding of TMS in solution [along with that of sodium-3- (trimethylsilyl)propanesulfonate, DSS, often used as a reference for aqueous solutions] varies only slightly with temperature but is subject to solvent perturbations of a few tenths of a part per million (ppm). Recommendations are given for reporting chemical shifts under most routine experimental conditions and for quantifying effects of temperature and solvent variation, including the use of magnetic susceptibility corrections and of magic-angle spinning (MAS). This document provides the first IUPAC recommendations for referencing and reporting chemical shifts in solids, based on high-resolution MAS studies. Procedures are given for relating 13 C NMR chemical shifts in solids to the scales used for high resolution studies in the liquid phase. The notation and terminology used for describing chemical shift and shielding tensors in solids are reviewed in some detail, and recommendations are given for best practice. (author)

  19. High resolution NMR spectroscopy of nanocrystalline proteins at ultra-high magnetic field

    International Nuclear Information System (INIS)

    Sperling, Lindsay J.; Nieuwkoop, Andrew J.; Lipton, Andrew S.; Berthold, Deborah A.; Rienstra, Chad M.

    2010-01-01

    Magic-angle spinning (MAS) solid-state NMR (SSNMR) spectroscopy of uniformly- 13 C, 15 N labeled protein samples provides insight into atomic-resolution chemistry and structure. Data collection efficiency has advanced remarkably in the last decade; however, the study of larger proteins is still challenged by relatively low resolution in comparison to solution NMR. In this study, we present a systematic analysis of SSNMR protein spectra acquired at 11.7, 17.6 and 21.1 Tesla ( 1 H frequencies of 500, 750, and 900 MHz). For two protein systems-GB1, a 6 kDa nanocrystalline protein and DsbA, a 21 kDa nanocrystalline protein-line narrowing is demonstrated in all spectral regions with increasing field. Resolution enhancement is greatest in the aliphatic region, including methine, methylene and methyl sites. The resolution for GB1 increases markedly as a function of field, and for DsbA, resolution in the C-C region increases by 42%, according to the number of peaks that can be uniquely picked and integrated in the 900 MHz spectra when compared to the 500 MHz spectra. Additionally, chemical exchange is uniquely observed in the highest field spectra for at least two isoleucine Cδ1 sites in DsbA. These results further illustrate the benefits of high-field MAS SSNMR spectroscopy for protein structural studies.

  20. Occurrence, biological activities and 13C NMR data of amides from Piper (Piperaceae

    Directory of Open Access Journals (Sweden)

    Jeferson C. do Nascimento

    2012-01-01

    Full Text Available This manuscript describes an update review with up to 285 references concerning the occurrence of amides from a variety of species of the genus Piper (Piperaceae. Besides addressing occurrence, this review also describes the biological activities attributed to extracts and pure compounds, a compiled 13C NMR data set, the main correlations between structural and NMR spectroscopic data of these compounds, and employment of hyphened techniques such as LC-MS, GC-MS and NMR for analysis of amides from biological samples and crude Piper extracts.

  1. Occurrence, biological activities and 13C NMR data of amides from Piper (Piperaceae)

    International Nuclear Information System (INIS)

    Nascimento, Jeferson C. do; Paula, Vanderlucia F. de; David, Jorge M.; David, Juceni P.

    2012-01-01

    This manuscript describes an update review with up to 285 references concerning the occurrence of amides from a variety of species of the genus Piper (Piperaceae). Besides addressing occurrence, this review also describes the biological activities attributed to extracts and pure compounds, a compiled 13 C NMR data set, the main correlations between structural and NMR spectroscopic data of these compounds, and employment of hyphened techniques such as LC-MS, GC-MS and NMR for analysis of amides from biological samples and crude Piper extracts. (author)

  2. Occurrence, biological activities and {sup 13}C NMR data of amides from Piper (Piperaceae)

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Jeferson C. do; Paula, Vanderlucia F. de [Universidade Estadual do Sudoeste da Bahia, Jequie, BA (Brazil). Dept. de Quimica e Exatas; David, Jorge M. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica; David, Juceni P., E-mail: jmdavid@ufba.br [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Fac. de Farmacia

    2012-07-01

    This manuscript describes an update review with up to 285 references concerning the occurrence of amides from a variety of species of the genus Piper (Piperaceae). Besides addressing occurrence, this review also describes the biological activities attributed to extracts and pure compounds, a compiled {sup 13}C NMR data set, the main correlations between structural and NMR spectroscopic data of these compounds, and employment of hyphened techniques such as LC-MS, GC-MS and NMR for analysis of amides from biological samples and crude Piper extracts. (author)

  3. Solid-State NMR Study of New Copolymers as Solid Polymer Electrolytes

    Directory of Open Access Journals (Sweden)

    Jean-Christophe Daigle

    2018-01-01

    Full Text Available We report the analysis of comb-like polymers by solid-state NMR. The polymers were previously evaluated as solid-polymer-electrolytes (SPE for lithium-polymer-metal batteries that have suitable ionic conductivity at 60 °C. We propose to develop a correlation between 13C solid-state NMR measurements and phase segregation. 13C solid-state NMR is a perfect tool for differentiating polymer phases with fast or slow motions. 7Li was used to monitor the motion of lithium ions in the polymer, and activation energies were calculated.

  4. 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...

  5. Effect of gamma radiation on lipids by the TBARS and NMR

    International Nuclear Information System (INIS)

    Silva, Adriana Cristina de Oliveira; Cortez, Marco Antonio Sloboda; Marsico, Eliane Teixeira; Guimaraes, Carlos Frederico; Jesus, Edgar Francisco Oliveira de

    2011-01-01

    The aim of this work was to study the effect of gamma radiation on lipids by TBARS and NMR. The samples of raw whole milk were subjected to gamma radiation from Co 60 in doses of 1, 2 and 3 kGy and the production of rancidity was studied through Nuclear Magnetic Resonance (NMR) and Thiobarbituric Acid Test (2-TBARS). The TBARS values increased according to the intensity of the radiation dose applied at the samples, demonstrating correlation between the radiation dose and the production of lipid oxidation. This was confirmed by NMR with the formation of peaks of aldehydes and ketones that were small and similar in the doses of 1 and 2 kGy. In the dose of 3 kGy, the total degradation of milk fat was observed. A correlation between the NMR and 2-TBA was detected. (author)

  6. Effect of gamma radiation on lipids by the TBARS and NMR

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Adriana Cristina de Oliveira; Cortez, Marco Antonio Sloboda, E-mail: vetdri@gmail.com [Lab. de Inspecao e Tecnologia de Leite e Derivados Lacteos, Faculdade de Medicina Veterinaria, Universidade Federal Fluminense, Niteroi - RJ (Brazil); Marsico, Eliane Teixeira; Guimaraes, Carlos Frederico [Laboratorio de Controle Fisico-Quimico de Produtos de Origem Animal, Faculdade de Medicina Veterinaria, Universidade Federal Fluminense, Niteroi - RJ (Brazil); Jesus, Edgar Francisco Oliveira de [Laboratorio de Instrumentacao Nuclear, Instituto Alberto Luiz Coimbra de Pos-graduacao e Pesquisa de Engenharia, Universidade Federal do Rio de Janeiro, Rio de Janeiro - RJ (Brazil)

    2011-11-15

    The aim of this work was to study the effect of gamma radiation on lipids by TBARS and NMR. The samples of raw whole milk were subjected to gamma radiation from Co{sup 60} in doses of 1, 2 and 3 kGy and the production of rancidity was studied through Nuclear Magnetic Resonance (NMR) and Thiobarbituric Acid Test (2-TBARS). The TBARS values increased according to the intensity of the radiation dose applied at the samples, demonstrating correlation between the radiation dose and the production of lipid oxidation. This was confirmed by NMR with the formation of peaks of aldehydes and ketones that were small and similar in the doses of 1 and 2 kGy. In the dose of 3 kGy, the total degradation of milk fat was observed. A correlation between the NMR and 2-TBA was detected. (author)

  7. Understanding API-polymer proximities in amorphous stabilized composite drug products using fluorine-carbon 2D HETCOR solid-state NMR.

    Science.gov (United States)

    Abraham, Anuji; Crull, George

    2014-10-06

    A simple and robust method for obtaining fluorine-carbon proximities was established using a (19)F-(13)C heteronuclear correlation (HETCOR) two-dimensional (2D) solid-state nuclear magnetic resonance (ssNMR) experiment under magic-angle spinning (MAS). The method was applied to study a crystalline active pharmaceutical ingredient (API), avagacestat, containing two types of fluorine atoms and its API-polymer composite drug product. These results provide insight into the molecular structure, aid with assigning the carbon resonances, and probe API-polymer proximities in amorphous spray dried dispersions (SDD). This method has an advantage over the commonly used (1)H-(13)C HETCOR because of the large chemical shift dispersion in the fluorine dimension. In the present study, fluorine-carbon distances up to 8 Å were probed, giving insight into the API structure, crystal packing, and assignments. Most importantly, the study demonstrates a method for probing an intimate molecular level contact between an amorphous API and a polymer in an SDD, giving insights into molecular association and understanding of the role of the polymer in API stability (such as recrystallization, degradation, etc.) in such novel composite drug products.

  8. Spin coherence transfer in chemical transformations monitoredNMR

    Energy Technology Data Exchange (ETDEWEB)

    Anwar, Sabieh M.; Hilty, Christian; Chu, Chester; Bouchard,Louis-S.; Pierce, Kimberly L.; Pines, Alexander

    2006-07-31

    We demonstrate the use of micro-scale nuclear magneticresonance (NMR) for studying the transfer of spin coherence innon-equilibrium chemical processes, using spatially separated NMRencoding and detection coils. As an example, we provide the map ofchemical shift correlations for the amino acid alanine as it transitionsfrom the zwitterionic to the anionic form. Our method is unique in thesense that it allows us to track the chemical migration of encodednuclear spins during the course of chemical transformations.

  9. Bone marrow NMR imaging and scintigraphy in AIDS patients

    International Nuclear Information System (INIS)

    Theisen, P.; Waters, W.; Schicha, H.; Rasokat, H.; Steigleder, G.K.

    1988-01-01

    The examinations were carried out in order to ascertain whether bone marrow abnormalities can be detected in AIDS patients by means of magnetic resonance imaging or scintiscanning. In 16 of the 19 patients the NMR image and/or the scintiscan distinctly revealed bone marrow abnormalities, but there was no exact correlation to be found to immunological parameters, the peripheral blood picture, or the clinical stage of the HIV infection. (orig.) [de

  10. 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.

  11. 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

  12. Chemical vs. electrochemical extraction of lithium from the Li-excess Li(1.10)Mn(1.90)O4 spinel followed by NMR and DRX techniques.

    Science.gov (United States)

    Martinez, S; Sobrados, I; Tonti, D; Amarilla, J M; Sanz, J

    2014-02-21

    Lithium extraction from the Li-excess Li1.10Mn1.90O4 spinel has been performed by chemical and electrochemical methods in aqueous and in organic media, respectively. De-lithiated samples have been investigated by XRD, SEM, TG, (7)Li and (1)H MAS-NMR techniques. The comparative study has allowed demonstrating that the intermediate de-intercalated samples prepared during the chemical extraction by acid titration are similar to those prepared by the electrochemical way in a non-aqueous electrolyte. LiMn2O4 based spinel with a tailored de-lithiation degree can be prepared as a single phase by controlling the pH used in chemical extraction. (7)Li MAS-NMR spectroscopy has been used to follow the influence of the manganese oxidation state on tetra and octahedral Li-signals detected in Li-extracted samples. The oxidation of Mn(III) ions goes parallel to the partial dissolution of the spinel, following Hunter's mechanism. Based on this mechanism, a generalized chemical reaction has been proposed to explain the formation of intermediate Li(+) de-intercalated samples during acid treatment in aqueous media. By the (1)H MAS NMR study, no evidence of Li-H topotactic exchange in the bulk of the acid treated material was found.

  13. 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.

  14. 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)

  15. Fusing in vivo and ex vivo NMR sources of information for brain tumor classification

    International Nuclear Information System (INIS)

    Croitor-Sava, A R; Laudadio, T; Sima, D M; Van Huffel, S; Martinez-Bisbal, M C; Celda, B; Piquer, J; Heerschap, A

    2011-01-01

    In this study we classify short echo-time brain magnetic resonance spectroscopic imaging (MRSI) data by applying a model-based canonical correlation analyses algorithm and by using, as prior knowledge, multimodal sources of information coming from high-resolution magic angle spinning (HR-MAS), MRSI and magnetic resonance imaging. The potential and limitations of fusing in vivo and ex vivo nuclear magnetic resonance sources to detect brain tumors is investigated. We present various modalities for multimodal data fusion, study the effect and the impact of using multimodal information for classifying MRSI brain glial tumors data and analyze which parameters influence the classification results by means of extensive simulation and in vivo studies. Special attention is drawn to the possibility of considering HR-MAS data as a complementary dataset when dealing with a lack of MRSI data needed to build a classifier. Results show that HR-MAS information can have added value in the process of classifying MRSI data

  16. Synthesis and evaluation of nitroxide-based oligoradicals for low-temperature dynamic nuclear polarization in solid state NMR

    Science.gov (United States)

    Yau, Wai-Ming; Thurber, Kent R.; Tycko, Robert

    2014-07-01

    We describe the synthesis of new nitroxide-based biradical, triradical, and tetraradical compounds and the evaluation of their performance as paramagnetic dopants in dynamic nuclear polarization (DNP) experiments in solid state nuclear magnetic resonance (NMR) spectroscopy with magic-angle spinning (MAS). Under our experimental conditions, which include temperatures in the 25-30 K range, a 9.4 T magnetic field, MAS frequencies of 6.2-6.8 kHz, and microwave irradiation at 264.0 GHz from a 800 mW extended interaction oscillator source, the most effective compounds are triradicals that are related to the previously-described compound DOTOPA-TEMPO (see Thurber et al., 2010), but have improved solubility in glycerol/water solvent near neutral pH. Using these compounds at 30 mM total nitroxide concentration, we observe DNP enhancement factors of 92-128 for cross-polarized 13C NMR signals from 15N,13C-labeled melittin in partially protonated glycerol/water, and build-up times of 2.6-3.8 s for 1H spin polarizations. Net sensitivity enhancements with biradical and tetraradical dopants, taking into account absolute 13C NMR signal amplitudes and build-up times, are approximately 2-4 times lower than with the best triradicals.

  17. A quasi-optical and corrugated waveguide microwave transmission system for simultaneous dynamic nuclear polarization NMR on two separate 14.1 T spectrometers

    Science.gov (United States)

    Dubroca, Thierry; Smith, Adam N.; Pike, Kevin J.; Froud, Stuart; Wylde, Richard; Trociewitz, Bianca; McKay, Johannes; Mentink-Vigier, Frederic; van Tol, Johan; Wi, Sungsool; Brey, William; Long, Joanna R.; Frydman, Lucio; Hill, Stephen

    2018-04-01

    Nuclear magnetic resonance (NMR) is an intrinsically insensitive technique, with Boltzmann distributions of nuclear spin states on the order of parts per million in conventional magnetic fields. To overcome this limitation, dynamic nuclear polarization (DNP) can be used to gain up to three orders of magnitude in signal enhancement, which can decrease experimental time by up to six orders of magnitude. In DNP experiments, nuclear spin polarization is enhanced by transferring the relatively larger electron polarization to NMR active nuclei via microwave irradiation. Here, we describe the design and performance of a quasi-optical system enabling the use of a single 395 GHz gyrotron microwave source to simultaneously perform DNP experiments on two different 14.1 T (1H 600 MHz) NMR spectrometers: one configured for magic angle spinning (MAS) solid state NMR; the other configured for solution state NMR experiments. In particular, we describe how the high power microwave beam is split, transmitted, and manipulated between the two spectrometers. A 13C enhancement of 128 is achieved via the cross effect for alanine, using the nitroxide biradical AMUPol, under MAS-DNP conditions at 110 K, while a 31P enhancement of 160 is achieved via the Overhauser effect for triphenylphosphine using the monoradical BDPA under solution NMR conditions at room temperature. The latter result is the first demonstration of Overhauser DNP in the solution state at a field of 14.1 T (1H 600 MHz). Moreover these results have been produced with large sample volumes (∼100 μL, i.e. 3 mm diameter NMR tubes).

  18. A quasi-optical and corrugated waveguide microwave transmission system for simultaneous dynamic nuclear polarization NMR on two separate 14.1 T spectrometers.

    Science.gov (United States)

    Dubroca, Thierry; Smith, Adam N; Pike, Kevin J; Froud, Stuart; Wylde, Richard; Trociewitz, Bianca; McKay, Johannes; Mentink-Vigier, Frederic; van Tol, Johan; Wi, Sungsool; Brey, William; Long, Joanna R; Frydman, Lucio; Hill, Stephen

    2018-04-01

    Nuclear magnetic resonance (NMR) is an intrinsically insensitive technique, with Boltzmann distributions of nuclear spin states on the order of parts per million in conventional magnetic fields. To overcome this limitation, dynamic nuclear polarization (DNP) can be used to gain up to three orders of magnitude in signal enhancement, which can decrease experimental time by up to six orders of magnitude. In DNP experiments, nuclear spin polarization is enhanced by transferring the relatively larger electron polarization to NMR active nuclei via microwave irradiation. Here, we describe the design and performance of a quasi-optical system enabling the use of a single 395 GHz gyrotron microwave source to simultaneously perform DNP experiments on two different 14.1 T ( 1 H 600 MHz) NMR spectrometers: one configured for magic angle spinning (MAS) solid state NMR; the other configured for solution state NMR experiments. In particular, we describe how the high power microwave beam is split, transmitted, and manipulated between the two spectrometers. A 13 C enhancement of 128 is achieved via the cross effect for alanine, using the nitroxide biradical AMUPol, under MAS-DNP conditions at 110 K, while a 31 P enhancement of 160 is achieved via the Overhauser effect for triphenylphosphine using the monoradical BDPA under solution NMR conditions at room temperature. The latter result is the first demonstration of Overhauser DNP in the solution state at a field of 14.1 T ( 1 H 600 MHz). Moreover these results have been produced with large sample volumes (∼100 µL, i.e. 3 mm diameter NMR tubes). Copyright © 2018 Elsevier Inc. All rights reserved.

  19. DNP-enhanced solid-state NMR spectroscopy of active pharmaceutical ingredients.

    Science.gov (United States)

    Zhao, Li; Pinon, Arthur C; Emsley, Lyndon; Rossini, Aaron J

    2017-11-28

    Solid-state NMR spectroscopy has become a valuable tool for the characterization of both pure and formulated active pharmaceutical ingredients (APIs). However, NMR generally suffers from poor sensitivity that often restricts NMR experiments to nuclei with favorable properties, concentrated samples, and acquisition of one-dimensional (1D) NMR spectra. Here, we review how dynamic nuclear polarization (DNP) can be applied to routinely enhance the sensitivity of solid-state NMR experiments by one to two orders of magnitude for both pure and formulated APIs. Sample preparation protocols for relayed DNP experiments and experiments on directly doped APIs are detailed. Numerical spin diffusion models illustrate the dependence of relayed DNP enhancements on the relaxation properties and particle size of the solids and can be used for particle size determination when the other factors are known. We then describe the advanced solid-state NMR experiments that have been enabled by DNP and how they provide unique insight into the molecular and macroscopic structure of APIs. For example, with large sensitivity gains provided by DNP, natural isotopic abundance, 13 C- 13 C double-quantum single-quantum homonuclear correlation NMR spectra of pure APIs can be routinely acquired. DNP also enables solid-state NMR experiments with unreceptive quadrupolar nuclei such as 2 H, 14 N, and 35 Cl that are commonly found in APIs. Applications of DNP-enhanced solid-state NMR spectroscopy for the molecular level characterization of low API load formulations such as commercial tablets and amorphous solid dispersions are described. Future perspectives for DNP-enhanced solid-state NMR experiments on APIs are briefly discussed. Copyright © 2017 John Wiley & Sons, Ltd.

  20. Systematic comparison of crystal and NMR protein structures deposited in the protein data bank.

    Science.gov (United States)

    Sikic, Kresimir; Tomic, Sanja; Carugo, Oliviero

    2010-09-03

    Nearly all the macromolecular three-dimensional structures deposited in Protein Data Bank were determined by either crystallographic (X-ray) or Nuclear Magnetic Resonance (NMR) spectroscopic methods. This paper reports a systematic comparison of the crystallographic and NMR results deposited in the files of the Protein Data Bank, in order to find out to which extent these information can be aggregated in bioinformatics. A non-redundant data set containing 109 NMR - X-ray structure pairs of nearly identical proteins was derived from the Protein Data Bank. A series of comparisons were performed by focusing the attention towards both global features and local details. It was observed that: (1) the RMDS values between NMR and crystal structures range from about 1.5 Å to about 2.5 Å; (2) the correlation between conformational deviations and residue type reveals that hydrophobic amino acids are more similar in crystal and NMR structures than hydrophilic amino acids; (3) the correlation between solvent accessibility of the residues and their conformational variability in solid state and in solution is relatively modest (correlation coefficient = 0.462); (4) beta strands on average match better between NMR and crystal structures than helices and loops; (5) conformational differences between loops are independent of crystal packing interactions in the solid state; (6) very seldom, side chains buried in the protein interior are observed to adopt different orientations in the solid state and in solution.

  1. 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.

  2. 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.

  3. Participation and Performance Reporting for the Alternate Assessment Based on Modified Achievement Standards (AA-MAS). Technical Report 58

    Science.gov (United States)

    Albus, Deb; Thurlow, Martha L.; Lazarus, Sheryl S.

    2011-01-01

    This report examines publicly reported participation and performance data for the alternate assessment based on modified achievement standards (AA-MAS). The authors' analysis of these data included all states publicly reporting AA-MAS data, regardless of whether they had received approval to use the results for Title I accountability calculations.…

  4. Angiotensin II Type 2 Receptor and Receptor Mas Are Colocalized and Functionally Interdependent in Obese Zucker Rat Kidney

    DEFF Research Database (Denmark)

    Patel, Sanket N; Ali, Quaisar; Samuel, Preethi

    2017-01-01

    The actions of angiotensin II type 2 receptor (AT2R) and the receptor Mas (MasR) are complex but show similar pronatriuretic function; particularly, AT2R expression and natriuretic function are enhanced in obese/diabetic rat kidney. In light of some reports suggesting a potential positive...... interaction between these receptors, we tested hypothesis that renal AT2R and MasR physically interact and are interdependent to stimulate cell signaling and promote natriuresis in obese rats. We found that infusion of AT2R agonist C21 in obese Zucker rats (OZR) increased urine flow and urinary Na excretion...... coimmunoprecipitated with MasR in cortical homogenate of OZR. Immunoblotting of cortical homogenate cross-linked with zero-length oxidative (sulfhydryl groups) cross-linker cupric-phenanthroline revealed a shift of AT2R and MasR bands upward with overlapping migration for their complexes which were sensitive...

  5. MAS-based Distributed Coordinated Control and Optimization in Microgrid and Microgrid Clusters: A Comprehensive Overview

    DEFF Research Database (Denmark)

    Han, Yang; Zhang, Ke; Hong, Li

    2018-01-01

    The increasing integration of the distributed renewable energy sources highlights the requirement to design various control strategies for microgrids (MGs) and microgrid clusters (MGCs). The multi-agent system (MAS)-based distributed coordinated control strategies shows the benefits to balance...... the power and energy, stabilize voltage and frequency, achieve economic and coordinated operation among the MGs and MGCs. However, the complex and diverse combinations of distributed generations in multi-agent system increase the complexity of system control and operation. In order to design the optimized...... configuration and control strategy using MAS, the topology models and mathematic models such as the graph topology model, non-cooperative game model, the genetic algorithm and particle swarm optimization algorithm are summarized. The merits and drawbacks of these control methods are compared. Moreover, since...

  6. Le Kāmasūtra et la « pulsion shastrique » en Inde

    OpenAIRE

    Naudou, Elizabeth

    2013-01-01

    Le mot « shastrique » fait référence au traité (śāstra) d’où sont issus les Kāmasūtra, (plus généralement appelé le Kāmasūtra), « aphorismes sur l’amour » : le Kāmaśāstra, « traité sur l’amour ». Qui dit śāstra, dit, en Inde, exposé religieux ou scientifique, d’où l’expression « pulsion shastrique » que l’on pourrait rendre par « pulsion encyclopédique énumérative et classificatoire ». Le but de cet exposé est de replacer le texte dans cette structure mentale typiquement indienne, qui reflète...

  7. El Proyecto Sismico "LARSE" - Trabajando Hacia un Futuro con Mas Seguridad para Los Angeles

    Science.gov (United States)

    Henyey, Thomas L.; Fuis, Gary S.; Benthien, Mark L.; Burdette, Thomas R.; Christofferson, Shari A.; Clayton, Robert W.; Criley, Edward E.; Davis, Paul M.; Hendley, James W.; Kohler, Monica D.; Lutter, William J.; McRaney, John K.; Murphy, Janice M.; Okaya, David A.; Ryberg, Trond; Simila, Gerald W.; Stauffer, Peter H.

    1999-01-01

    La region de Los Angeles contiene una red de fallas activas, incluyendo muchas fallas por empuje que son profundas y no rompen la superficie de la tierra. Estas fallas ocultas incluyen la falla anteriormente desconocida que fue responsable por la devastacion que ocurrio durante el terremoto de Northridge en enero de 1994, el terremoto mas costoso en la historia de los Estados Unidos. El Experimento Sismico en la Region de Los Angeles (Los Angeles Region Seismic Experiment, LARSE), esta localizando los peligros ocultos de los terremotos debajo de la region de Los Angeles para mejorar la construccion de las estructuras que pueden apoyar terremotos que son inevitables en el futuro, y que ayudaran a los cientificos determinar donde occurira el sacudimento mas fuerte y poderoso.

  8. 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.

  9. Efficient design of multituned transmission line NMR probes: the electrical engineering approach.

    Science.gov (United States)

    Frydel, J A; Krzystyniak, M; Pienkowski, D; Pietrzak, M; de Sousa Amadeu, N; Ratajczyk, T; Idzik, K; Gutmann, T; Tietze, D; Voigt, S; Fenn, A; Limbach, H H; Buntkowsky, G

    2011-01-01

    Transmission line-based multi-channel solid state NMR probes have many advantages regarding the cost of construction, number of RF-channels, and achievable RF-power levels. Nevertheless, these probes are only rarely employed in solid state-NMR-labs, mainly owing to the difficult experimental determination of the necessary RF-parameters. Here, the efficient design of multi-channel solid state MAS-NMR probes employing transmission line theory and modern techniques of electrical engineering is presented. As technical realization a five-channel ((1)H, (31)P, (13)C, (2)H and (15)N) probe for operation at 7 Tesla is described. This very cost efficient design goal is a multi port single coil transmission line probe based on the design developed by Schaefer and McKay. The electrical performance of the probe is determined by measuring of Scattering matrix parameters (S-parameters) in particular input/output ports. These parameters are compared to the calculated parameters of the design employing the S-matrix formalism. It is shown that the S-matrix formalism provides an excellent tool for examination of transmission line probes and thus the tool for a rational design of these probes. On the other hand, the resulting design provides excellent electrical performance. From a point of view of Nuclear Magnetic Resonance (NMR), calibration spectra of particular ports (channels) are of great importance. The estimation of the π/2 pulses length for all five NMR channels is presented. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Solid state NMR, basic theory and recent progress for quadrupole nuclei with half-integer spin

    International Nuclear Information System (INIS)

    Dieter, F.

    1998-01-01

    This review describes the basic theory and some recently developed techniques for the study of quadrupole nuclei with half integer spins in powder materials. The latter is connected to the introduction of the double rotation (DOR) by A. Samoson et al. (1) and to the introduction of the multiple quantum magic-angle spinning (MQ MAS) technique by L. Frydman et. al. (2). For integer spins, especially the solid-state deuterium magnetic resonance, we refer to the review of G.L. Hoatson and R.L. Vold: '' 2 H-NMR Spectroscopy of Solids and Liquid Crystals'' (3). For single crystals we refer to O. Kanert and M. Mehring: ''Static quadrupole effects in disordered cubic solids''(4) and we would like also to mention the ''classic'' review of M.H. Cohen and F. Reif: ''Quadrupole effects in NMR studies of solids'' (5). Some more recent reviews in the field under study are D. Freude and J. Haase ''Quadrupole effects in solid-state NMR'' (6). Ch. Jager: ''Satellite Transition Spectroscopy of Quadrupolar Nuclei'' (7) and B.F. Chmelka and J.W. Zwanziger: ''Solid State NMR Line Narrowing Methods for Quadrupolar Nuclei - Double Rotation and Dynamic-Angle Spinning'' (8). A survey of nuclear quadrupole frequency data published before the end of 1982 is given by H. Chihara and N. Nakamura in Landolt-Bornstein, Vol. 20 (9). Values of the chemical shift of quadrupole nuclei in solids can be found in books such as ''Multinuclear NMR'' edited by J. Mason (10). In section 9 of ref (6) some electric field gradient and chemical shift data published from 1983 to 1992 for the most studied quadrupole nuclei sup 27 Al, sup 23 Na, and sup 17 O are given

  11. Solid NMR study of lithium ions accommodated in various transition metal oxides

    International Nuclear Information System (INIS)

    Kanzaki, Yasushi; Suzuki, Noriko

    2008-01-01

    Solid NMR was used to elucidate the lithium accommodation/extraction reaction in various transition metal oxides. The first study was the lithium ion exchange reaction of titanium antimonic acid (TiSbA). The effect of hydration on the selectivity of lithium ion in the solid phase was examined using 7 Li NMR. The second study was the irreversible ion exchange behavior of HNbO 3 . The selectivity for the lithium ion and the irreversible behavior were examined using 1 H and 7 Li NMR. The third study was the isotope separation between 6 Li and 7 Li in various inorganic ion exchangers. The high isotope separation coefficient was ascribed to the degree of dehydration during the ion exchange reaction. The degree of dehydration was examined by 1 H and 7 Li NMR studies. The last study was determining the mechanism of the lithium accommodation/extraction reaction of λ-MnO 2 in an aqueous solution. The different paths between the accommodation and extraction and the formation of MnO 4- during the accommodation were determined by chemical analysis. The Knight shift in the 7 Li MAS-NMR spectra of Li 0.5 MnO 2 suggested the localization of the electron density on the lithium nuclei. An XPS study also suggested the presence of an electron density on the lithium nuclei. A pH-independent redox couple was assumed to account for the accommodation/extraction reaction of lithium ions, such as Li(I)/Li(0). (author)

  12. Mas Gusó: a Roman military Settlement in the suburbium of Emporiae

    Directory of Open Access Journals (Sweden)

    Josep Casas Genover

    2016-11-01

    Full Text Available Although the site of Mas Gusó (province of Girona has been interpreted as a Roman uilla, this is actually a public building. Its existence have to be contextualized within the frame of the structures established by the Roman authority for territorial control closely linked to the creation of a new road network and a tax collection system. We also analyse its survival until the 3rd century AD, which are closely related to the nearby city of Emporiae.

  13. 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.

  14. NMR metabolomics for assessment of exercise effects with mouse biofluids

    Energy Technology Data Exchange (ETDEWEB)

    Le Moyec, Laurence; Mille-Hamard, Laurence; Breuneval, Carole; Petot, Helene; Billat, Veronique L. [Universite Evry Val d' Essonne, UBIAE INSERM U902, Evry Cedex (France); Triba, Mohamed N. [Universite Paris 13, CSPBAT UMR 7244, Bobigny (France)

    2012-08-15

    Exercise modulates the metabolome in urine or blood as demonstrated previously for humans and animal models. Using nuclear magnetic resonance (NMR) metabolomics, the present study compares the metabolic consequences of an exhaustive exercise at peak velocity (Vp) and at critical velocity (Vc) on mice. Since small-volume samples (blood and urine) were collected, dilution was necessary to acquire NMR spectra. Consequently, specific processing methods were applied before statistical analysis. According to the type of exercise (control group, Vp group and Vc group), 26 male mice were divided into three groups. Mice were sacrificed 2 h after the end of exercise, and urine and blood samples were drawn from each mouse. Proton NMR spectra were acquired with urine and deproteinized blood. The NMR data were aligned with the icoshift method and normalised using the probabilistic quotient method. Finally, data were analysed with the orthogonal projection of latent-structure analysis. The spectra obtained with deproteinized blood can neither discriminate the control mice from exercised mice nor discriminate according to the duration of the exercise. With urine samples, a significant statistical model can be estimated when comparing the control mice to both groups, Vc and Vp. The best model is obtained according to the exercise duration with all mice. Taking into account the spectral regions having the highest correlations, the discriminant metabolites are allantoin, inosine and branched-chain amino acids. In conclusion, metabolomic profiles assessed with NMR are highly dependent on the exercise. These results show that urine samples are more informative than blood samples and that the duration of the exercise is a more important parameter to influence the metabolomic status than the exercise velocity. (orig.)

  15. Effectiveness of FitoMas-E in the cultivation of chickpea under two soil moisture levels

    Directory of Open Access Journals (Sweden)

    Yanitza Meriño Hernández

    2018-01-01

    Full Text Available To evaluate the effect of FitoMas-E on the performance of the chickpea, in conditions of drought stress, was the objective of this investigation. An experiment was conducted in the Intensive Garden "Río de Guisa" in the municipality of Guisa during the period from November to February 2014. Four treatments were applied, distributed in a randomized block design with three repetitions, on a "Pardo mullido grisaceo" soil, comparing the application of FitoMas-E under two soil moisture regimes, with and without water stress. The yield of grain and its components were evaluated at the time of harvest maturity, to analyze the responses of these variables to the treatments applied. An analysis of variance was performed using the statistical package STASTISTICA version 8.0 for Windows and the means of the treatments were compared using the Tukey Multiple Range test. The variables that showed a greater response to the treatments imposed were the number of legumes per plant, number of seeds per plant, the mass of 100 seeds and the yield of grain, which ranged between 0.9 and 0.93 t ha-1 for the treatments 2 and 4 respectively. The results obtained in this research showed that the chickpea crop achieved the best productive indicators when the plants were under water stress conditions and received the application of FitoMas-E.

  16. Stanowisko badawcze do oceny efektów utwardzania mas ze szkłem wodnym

    Directory of Open Access Journals (Sweden)

    M. Stachowicz

    2012-12-01

    Full Text Available W pracy przedstawiono wyniki badań nad możliwością zastosowania nowego stanowiska badawczego do oceny, na podstawie końcowejzawartości wody, finalnego efektu utwardzania wybranymi metodami mas ze szkłem wodnym. Badania wykonano na innowacyjnym,mobilnym stanowisku mikrofalowej linii szczelinowej wykorzystującej zjawisko występowania fali stojącej w falowodzie. Badaniompoddano pięć mas sporządzonych z dostępnymi w handlu gatunkami szkła wodnego, które utwardzano trzema, wybranymi metodami:mikrofalową, klasyczną oraz w procesie CO2. Wykazano, na przykładzie mas ze szkłem wodnym, że prezentowane, mobilne stanowiskopomiarowe może, na podstawie określenia końcowej zawartości wody, służyć z powodzeniem do oceny ostatecznego efektu utwardzaniamas formierskich i rdzeniowych.

  17. 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...

  18. SYNTHESIS, IR AND NMR SPECTRAL CORRELATIONS IN SOME ...

    African Journals Online (AJOL)

    Preferred Customer

    reaction of interest to chemists up to date in the fields of macrocyclic and supramolecular chemistry. The diimines or bisimines or bis-Schiff's bases also been ... [12] have studied the effects of substituent on infrared C=N, nuclear magnetic ...

  19. 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.

  20. 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

  1. 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

  2. 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.

  3. 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.

  4. Variable angle correlation spectroscopy

    International Nuclear Information System (INIS)

    Lee, Y.K.; Lawrence Berkeley Lab., CA

    1994-05-01

    In this dissertation, a novel nuclear magnetic resonance (NMR) technique, variable angle correlation spectroscopy (VACSY) is described and demonstrated with 13 C nuclei in rapidly rotating samples. These experiments focus on one of the basic problems in solid state NMR: how to extract the wealth of information contained in the anisotropic component of the NMR signal while still maintaining spectral resolution. Analysis of the anisotropic spectral patterns from poly-crystalline systems reveal information concerning molecular structure and dynamics, yet in all but the simplest of systems, the overlap of spectral patterns from chemically distinct sites renders the spectral analysis difficult if not impossible. One solution to this problem is to perform multi-dimensional experiments where the high-resolution, isotropic spectrum in one dimension is correlated with the anisotropic spectral patterns in the other dimensions. The VACSY technique incorporates the angle between the spinner axis and the static magnetic field as an experimental parameter that may be incremented during the course of the experiment to help correlate the isotropic and anisotropic components of the spectrum. The two-dimensional version of the VACSY experiments is used to extract the chemical shift anisotropy tensor values from multi-site organic molecules, study molecular dynamics in the intermediate time regime, and to examine the ordering properties of partially oriented samples. The VACSY technique is then extended to three-dimensional experiments to study slow molecular reorientations in a multi-site polymer system

  5. 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)

  6. Carbon-13 solid state NMR studies in the aromatization of residual coals from hydropyrolised cellulose; Estudo por {sup 13} C RMN em estado solido da aromatizacao em carvoes residuais de celulose hidropirolisada

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, J.D.; Luengo, C.A. [Universidade Estadual de Campinas, SP (Brazil). Inst. de Fisica; Snape, C.A. [Dept. Pure and Apllied Chemistry, Glasgow (United Kingdom)

    1997-12-31

    Pure cellulose was pyrolyzed is a fixed-bed reactor under hydrogen pressure (hydropyrolysis). Residual chars were collected and analysed by solid state nmr {sup 13} C (CP-MAS) and elemental. Hydrophyrolysis parameters such as final temperature in the range of 300 to 520 deg C and hydrogen pressure from 5 to 100 atm gave different char samples. CP-MAS spectra were obtained in a BRUKER MSL-100 spectrometer. The results showed that the aromatic and aliphatic fractions had strong dependence with temperature and no influence with pressure. Elemental analysis indicated the carbon content increased more with temperature than the pressure increasing. (author) 6 refs., 2 figs., 2 tabs.

  7. Sensitivity and Resolution Enhanced Solid-State NMR for Paramagnetic Systems and Biomolecules under Very Fast Magic Angle Spinning

    KAUST Repository

    Parthasarathy, Sudhakar

    2013-09-17

    Recent research in fast magic angle spinning (MAS) methods has drastically improved the resolution and sensitivity of NMR spectroscopy of biomolecules and materials in solids. In this Account, we summarize recent and ongoing developments in this area by presenting (13)C and (1)H solid-state NMR (SSNMR) studies on paramagnetic systems and biomolecules under fast MAS from our laboratories. First, we describe how very fast MAS (VFMAS) at the spinning speed of at least 20 kHz allows us to overcome major difficulties in (1)H and (13)C high-resolution SSNMR of paramagnetic systems. As a result, we can enhance both sensitivity and resolution by up to a few orders of magnitude. Using fast recycling (∼ms/scan) with short (1)H T1 values, we can perform (1)H SSNMR microanalysis of paramagnetic systems on the microgram scale with greatly improved sensitivity over that observed for diamagnetic systems. Second, we discuss how VFMAS at a spinning speed greater than ∼40 kHz can enhance the sensitivity and resolution of (13)C biomolecular SSNMR measurements. Low-power (1)H decoupling schemes under VFMAS offer excellent spectral resolution for (13)C SSNMR by nominal (1)H RF irradiation at ∼10 kHz. By combining the VFMAS approach with enhanced (1)H T1 relaxation by paramagnetic doping, we can achieve extremely fast recycling in modern biomolecular SSNMR experiments. Experiments with (13)C-labeled ubiquitin doped with 10 mM Cu-EDTA demonstrate how effectively this new approach, called paramagnetic assisted condensed data collection (PACC), enhances the sensitivity. Lastly, we examine (13)C SSNMR measurements for biomolecules under faster MAS at a higher field. Our preliminary (13)C SSNMR data of Aβ amyloid fibrils and GB1 microcrystals acquired at (1)H NMR frequencies of 750-800 MHz suggest that the combined use of the PACC approach and ultrahigh fields could allow for routine multidimensional SSNMR analyses of proteins at the 50-200 nmol level. Also, we briefly discuss the

  8. 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

  9. Development and Investigation of NMR tools for chiral compound identification

    Energy Technology Data Exchange (ETDEWEB)

    Alam, Todd Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Electronic, Optical and Nano Materials; Lansdon, Rick [Oak Ridge Inst. for Science and Education (ORISE), Oak Ridge, TN (United States)

    2014-09-01

    The goal behind the assigned summer project was to investigate the ability of nuclear magnetic resonance spectroscopy (NMR) to identify enantiomers of select chiral organo-fluorophosphates (OFPs) compounds which are analogs of chemical warfare agents (CWAs, e.g. Sarin). This involved investigations utilizing chiral solvating agents (CSAs) and characterizing the binding phenomena with cyclodextrins. The resolution of OFPs enantiomers using NMR would be useful for research into toxicodynamics and toxicokinetics in biological systems due to the widely differing properties of the CWA enantiomers [1]. The optimization of decontamination abilities in the case of a CWA events, with this method’s potential rapidity and robustness, as well as the development of models correlating chiral compounds with CSAs for optimal resolution are all rational benefits of this research.

  10. Peakr: simulating solid-state NMR spectra of proteins

    International Nuclear Information System (INIS)

    Schneider, Robert; Odronitz, Florian; Hammesfahr, Bjorn; Hellkamp, Marcel; Kollmar, Martin

    2013-01-01

    When analyzing solid-state nuclear magnetic resonance (NMR) spectra of proteins, assignment of resonances to nuclei and derivation of restraints for 3D structure calculations are challenging and time-consuming processes. Simulated spectra that have been calculated based on, for example, chemical shift predictions and structural models can be of considerable help. Existing solutions are typically limited in the type of experiment they can consider and difficult to adapt to different settings. Here, we present Peakr, a software to simulate solid-state NMR spectra of proteins. It can generate simulated spectra based on numerous common types of internuclear correlations relevant for assignment and structure elucidation, can compare simulated and experimental spectra and produces lists and visualizations useful for analyzing measured spectra. Compared with other solutions, it is fast, versatile and user friendly. (authors)

  11. NMR structural studies of oligosaccharides and other natural products

    DEFF Research Database (Denmark)

    Kjærulff, Louise

    produce secondary metabolites for signaling and competing against other organisms, and these molecules are important in drug discovery due to their inherent biological activities. From a marine Photobacterium (P. halotolerans) we isolated the solonamides and the ngercheumicins, two families of cyclic...... through the nJCH correlation, this experiment has exciting applications for configurational assignment of e.g. carbohydrates and for residual dipolar couplings. Identification of known molecules and discovery of novel molecules are other important applications of NMR spectroscopy. Bacteria and fungi....... fijiensis, was also investigated for production of novel secondary metabolites, and a new pyranonigrin (E) was isolated and structure elucidated by NMR spectroscopy along with JBIR-74 and decumbenone A, two known metabolites previously isolated from Aspergillus and Penicillium species. Oligosaccharides...

  12. Nano-mole scale sequential signal assignment by 1 H-detected protein solid-state NMR

    KAUST Repository

    Wang, Songlin; Parthasarathy, Sudhakar; Xiao, Yiling; Nishiyama, Yusuke; Long, Fei; Matsuda, Isamu; Endo, Yuki; Nemoto, Takahiro; Yamauchi, Kazuo; Asakura, Tetsuo; Takeda, Mitsuhiro; Terauchi, Tsutomu; Kainosho, Masatsune; Ishii, Yoshitaka

    2015-01-01

    We present a 3D 1H-detected solid-state NMR (SSNMR) approach for main-chain signal assignments of 10-100 nmol of fully protonated proteins using ultra-fast magic-angle spinning (MAS) at ∼80 kHz by a novel spectral-editing method, which permits drastic spectral simplification. The approach offers ∼110 fold time saving over a traditional 3D 13C-detected SSNMR approach. This journal is © The Royal Society of Chemistry 2015.

  13. Metabolic engineering applications of in vivo 31P and 13C NMR studies of Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Shanks, J.V.

    1989-01-01

    With intent to quantify NMR measurements as much as possible, analysis techniques of the in vivo 31 P NMR spectrum are developed. A systematic procedure is formulated for estimating the relative intracellular concentrations of the sugar phosphates in S. cerevisiae from the 31 P NMR spectrum. In addition, in vivo correlation of inorganic phosphate chemical shift with the chemical shifts of 3-phosphoglycerate, β-fructose 1,6-diphosphate, fructose 6-phosphate, and glucose 6-phosphate are determined. Also, a method was developed for elucidation of the cytoplasmic and vacuolar components of inorganic phosphate in the 31 P NMR spectrum of S. cerevisiae. An in vivo correlation relating the inorganic phosphate chemical shift of the vacuole with the chemical shift of the resonance for pyrophosphate and the terminal phosphate of polyphosphate (PP 1 ) is established. Transient measurements provided by 31 P NMR are applied to reg1 mutant and standard strains. 31 P and 13 C NMR measurements are used to analyze the performance of recombinant strains in which the glucose phosphorylation step had been altered

  14. Validation of interventional fiber optic spectroscopy with MR Spectroscopy, MAS-NMR spectroscopy, high-performance thin-layer chromatography, and histopathology for accurate hepatic fat quantification

    NARCIS (Netherlands)

    Nachabé, R.; Hoorn, J.W.A. van der; Molengraaf, R. van de; Lamerichs, R.; Pikkemaat, J.; Sio, C.F.; Hendriks, B.H.W.; Sterenborg, H.J.C.M.

    2012-01-01

    Objectives: To validate near-infrared (NIR)-based optical spectroscopy measurements of hepatic fat content using a minimally invasive needle-like probe with integrated optical fibers, enabling real-time feedback during percutaneous interventions. The results were compared with magnetic resonance

  15. 119Sn MAS NMR Study of Probe Molecules Interaction with Sn-BEA: The Origin of Penta- and Hexacoordinated Tin Formation

    DEFF Research Database (Denmark)

    Yakimov, Alexander V.; G. Kolyagin, Yury; Tolborg, Søren

    2016-01-01

    and weak Lewis acidity, respectively. The adsorption of acetonitrile and methanol resulted in observation of pentacoordinated tin species, due to the formation of 1:1 adsorption complexes over both Sn-sites. Water adsorption led first to formation of pentacoordinated tin species, which were further...... by the formation of pentacoordinated Sn species in the case of weak sites and hexacoordinated Sn over sites with strong Lewis acidity, pointing to the possibility of dissociative adsorption of secondary alcohols over strong Sn-sites....

  16. Deactivation by polysiloxane and phenyl containing disilazane : a 29Si CP-MAS NMR study after the formation of polysiloxane chains at the surface

    NARCIS (Netherlands)

    Hetem, M.J.J.; Rutten, G.A.F.M.; Ven, van de L.J.M.; Haan, de J.W.; Cramers, C.A.M.G.

    1988-01-01

    A high degree of deactivation of glass and fused-silica capillary column walls is attainable by means of high temperature silylation (HTS) with or without a preceding leaching process. HTS with a phenyl containing disilazane, diphenyltetramethyldisilazane (DPTMDS), and polydimethylsiloxane (PDMS)

  17. APPLICATION OF A C-13 NMR TOPOLOGICAL MODEL TO THE STRUCTURE ELUCIDATION OF ORGANIC COMPOUNDS

    Institute of Scientific and Technical Information of China (English)

    袁身刚; 彭琛; 郑崇直

    1992-01-01

    This paper presents an approach which can elucidate automatically the structures of simple organic compounds from their C-13 NMR spectral data by using a computer. Based on a substructure/C-13 NMR chemical shift topological correlation model, the approach deduces the candidate substructures and the constraints for the substructure assembling from the molecular formula and C-13 NMR spectral data. Then, candidate structures are generated under these constraints by assembling the candidate substructures in a partial superposition manner. Candidate substructures or structures are evaluated once they are generated in order to eliminate those conflicting with the original data as early as possible. The evaluation of a (sub)structure is mainly carried out by simulating its C-13 NMR (sub) spectrum, which is again based on the model, and comparing the simulated spectrum with the original data.

  18. Method of detecting cancer by measuring lipid-peroxidation using NMR

    International Nuclear Information System (INIS)

    Fossel, E.T.

    1992-01-01

    A technique and an apparatus are disclosed for the detection of cancer using nuclear magnetic resonance (NMR). Specifically, NMR parameters for protons of lipid methyl and/or methylene groups are determined and compared against a corresponding value for healthy patients. Suppression of the water proton signal is employed where necessary in order to obtain a suitable spectrum for the non-water component protons. In the event that a positive reading is obtained, the level of plasma triglycerides is determined and if it is high, the patient's bodily fluid sample is further subjected to second nuclear magnetic spectroscopy. The area or the intensity of the portion correlating to 2.0 and 2.8 ppm of the resonance line generated in the second NMR is measured which discriminates between true and false positive results from the proton NMR reading and determines the presence or absence of cancer in the patient

  19. NPK NMR Sensor: Online Monitoring of Nitrogen, Phosphorus, and Potassium in Animal Slurry.

    Science.gov (United States)

    Sørensen, Morten K; Jensen, Ole; Bakharev, Oleg N; Nyord, Tavs; Nielsen, Niels Chr

    2015-07-07

    Knowledge of the actual content of nitrogen, phosphorus, and potassium (NPK) in animal slurry is highly important to optimize crop production and avoid environmental pollution when slurry is spread on agricultural fields. Here, we present a mobile, low-field nuclear magnetic resonance (NMR) sensor suitable for online monitoring of the NPK content in animal slurry as an alternative to crude estimates or tedious nonspecific, off-site laboratory analysis. The sensor is based on (14)N, (17)O, (31)P, and (39)K NMR in a digital NMR instrument equipped with a 1.5 T Halbach magnet for direct detection of ammonium N, total P, and K and indirect evaluation of the organic N content, covering all practical components of NPK in animal slurry. In correlation studies, the obtained NMR measurements show good agreement with reference measurements from commercial laboratories.

  20. Evaluation of thermoplastic starch/MMT nanocomposites by nuclear magnetic resonance (NMR); Avaliacao de nanocompositos de amido termoplastico e argila por RMN

    Energy Technology Data Exchange (ETDEWEB)

    Schlemmer, D.; Rodrigues, Tiago C.A.F.; Resck, I.S.; Sales, M.J.A., E-mail: danielas@unb.b [Universidade de Brasilia (LabPol/UnB), DF (Brazil). Inst. de Quimica. Lab. de Pesquisa em Polimeros

    2010-07-01

    Starch has been studied for replace petrochemical plastics for short shelf life. However, the starch films have limitations: sensitivity to moisture and poor mechanical strength. This can be improved by incorporating loads such as montmorillonite, forming nanocomposites. Nanocomposites were prepared with 1, 3, 5 and 10% of montmorillonite, using vegetable oils of Brazilian Cerrado as plasticizers. The NMR spectra of oils are similar, but the intensities of the signals varying with the proportion of fatty acids. The molar mass of the oils was also calculated by NMR. The spectrum of CP/MAS {sup 13}C NMR for starch presented a duplet in 97 and 98 ppm, on the amorphous domains of C-1, indicating a crystal type A. The spectra of the nanocomposites are similar to those of starch and oils. No new peaks appear, suggesting that there are no strong chemical bonds between components. (author)

  1. 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.)

  2. 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

  3. 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

  4. 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…

  5. 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)

  6. 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…

  7. 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

  8. 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

  9. 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 ...

  10. 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.)

  11. 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

  12. Transformation of meta-stable calcium silicate hydrates to tobermorite: reaction kinetics and molecular structure from XRD and NMR spectroscopy

    Science.gov (United States)

    2009-01-01

    Understanding the integrity of well-bore systems that are lined with Portland-based cements is critical to the successful storage of sequestered CO2 in gas and oil reservoirs. As a first step, we investigate reaction rates and mechanistic pathways for cement mineral growth in the absence of CO2 by coupling water chemistry with XRD and NMR spectroscopic data. We find that semi-crystalline calcium (alumino-)silicate hydrate (Al-CSH) forms as a precursor solid to the cement mineral tobermorite. Rate constants for tobermorite growth were found to be k = 0.6 (± 0.1) × 10-5 s-1 for a solution:solid of 10:1 and 1.6 (± 0.8) × 10-4 s-1 for a solution:solid of 5:1 (batch mode; T = 150°C). This data indicates that reaction rates for tobermorite growth are faster when the solution volume is reduced by half, suggesting that rates are dependent on solution saturation and that the Gibbs free energy is the reaction driver. However, calculated solution saturation indexes for Al-CSH and tobermorite differ by less than one log unit, which is within the measured uncertainty. Based on this data, we consider both heterogeneous nucleation as the thermodynamic driver and internal restructuring as possible mechanistic pathways for growth. We also use NMR spectroscopy to characterize the site symmetry and bonding environment of Al and Si in a reacted tobermorite sample. We find two [4]Al coordination structures at δiso = 59.9 ppm and 66.3 ppm with quadrupolar product parameters (PQ) of 0.21 MHz and 0.10 MHz (± 0.08) from 27Al 3Q-MAS NMR and speculate on the Al occupancy of framework sites by probing the protonation environment of Al metal centers using 27Al{1H}CP-MAS NMR. PMID:19144195

  13. 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...

  14. Solid-state NMR of the Yersinia pestis outer membrane protein Ail in lipid bilayer nanodiscs sedimented by ultracentrifugation

    International Nuclear Information System (INIS)

    Ding, Yi; Fujimoto, L. Miya; Yao, Yong; Marassi, Francesca M.

    2015-01-01

    Solid-state NMR studies of sedimented soluble proteins has been developed recently as an attractive approach for overcoming the size limitations of solution NMR spectroscopy while bypassing the need for sample crystallization or precipitation (Bertini et al. Proc Natl Acad Sci USA 108(26):10396–10399, 2011). Inspired by the potential benefits of this method, we have investigated the ability to sediment lipid bilayer nanodiscs reconstituted with a membrane protein. In this study, we show that nanodiscs containing the outer membrane protein Ail from Yersinia pestis can be sedimented for solid-state NMR structural studies, without the need for precipitation or lyophilization. Optimized preparations of Ail in phospholipid nanodiscs support both the structure and the fibronectin binding activity of the protein. The same sample can be used for solution NMR, solid-state NMR and activity assays, facilitating structure–activity correlation experiments across a wide range of timescales

  15. Solid-state NMR of the Yersinia pestis outer membrane protein Ail in lipid bilayer nanodiscs sedimented by ultracentrifugation

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Yi; Fujimoto, L. Miya; Yao, Yong; Marassi, Francesca M., E-mail: fmarassi@sbmri.org [Sanford-Burnham Medical Research Institute (United States)

    2015-04-15

    Solid-state NMR studies of sedimented soluble proteins has been developed recently as an attractive approach for overcoming the size limitations of solution NMR spectroscopy while bypassing the need for sample crystallization or precipitation (Bertini et al. Proc Natl Acad Sci USA 108(26):10396–10399, 2011). Inspired by the potential benefits of this method, we have investigated the ability to sediment lipid bilayer nanodiscs reconstituted with a membrane protein. In this study, we show that nanodiscs containing the outer membrane protein Ail from Yersinia pestis can be sedimented for solid-state NMR structural studies, without the need for precipitation or lyophilization. Optimized preparations of Ail in phospholipid nanodiscs support both the structure and the fibronectin binding activity of the protein. The same sample can be used for solution NMR, solid-state NMR and activity assays, facilitating structure–activity correlation experiments across a wide range of timescales.

  16. MAS: Malware Analysis System Based on Hardware-Assisted Virtualization Technology

    Science.gov (United States)

    Kim, Taehyoung; Kim, Inhyuk; Min, Changwoo; Eom, Young Ik

    There are many analysis techniques in order to analyze malicious codes. However, recently malicious codes often evade detection using stealthy obfuscation techniques, and attack computing systems. We propose an enhanced dynamic binary instrumentation using hardware-assisted virtualization technology. As a machine-level analyzer, our system can be isolated from almost the whole threats of malware, and provides single step analysis environment. Proposed system also supports rapid system call analysis environment. We implement our malware analysis system (referred as MAS) on the KVM hypervisor with Intel VT-x virtualization support. Our experiments with benchmarks show that the proposed system provides efficient analysis environment with low overhead.

  17. Comparison of NMR and crystal structures for the proteins TM1112 and TM1367

    International Nuclear Information System (INIS)

    Mohanty, Biswaranjan; Serrano, Pedro; Pedrini, Bill; Jaudzems, Kristaps; Geralt, Michael; Horst, Reto; Herrmann, Torsten; Elsliger, Marc-André; Wilson, Ian A.; Wüthrich, Kurt

    2010-01-01

    NMR structures of the proteins TM1112 and TM1367 solved by the JCSG in solution at 298 K could be superimposed with the corresponding crystal structures at 100 K with r.m.s.d. values of <1.0 Å for the backbone heavy atoms. For both proteins the structural differences between multiple molecules in the asymmetric unit of the crystals correlated with structural variations within the bundles of conformers used to represent the NMR solution structures. A recently introduced JCSG NMR structure-determination protocol, which makes use of the software package UNIO for extensive automation, was further evaluated by comparison of the TM1112 structure obtained using these automated methods with another NMR structure that was independently solved in another PSI center, where a largely interactive approach was applied. The NMR structures of the TM1112 and TM1367 proteins from Thermotoga maritima in solution at 298 K were determined following a new protocol which uses the software package UNIO for extensive automation. The results obtained with this novel procedure were evaluated by comparison with the crystal structures solved by the JCSG at 100 K to 1.83 and 1.90 Å resolution, respectively. In addition, the TM1112 solution structure was compared with an NMR structure solved by the NESG using a conventional largely interactive methodology. For both proteins, the newly determined NMR structure could be superimposed with the crystal structure with r.m.s.d. values of <1.0 Å for the backbone heavy atoms, which provided a starting platform to investigate local structure variations, which may arise from either the methods used or from the different chemical environments in solution and in the crystal. Thereby, these comparative studies were further explored with the use of reference NMR and crystal structures, which were computed using the NMR software with input of upper-limit distance constraints derived from the molecular models that represent the results of structure

  18. MODIS Airborne Simulator (MAS) Measurements Taken Onboard the NASAER-2 During the TOGA COARE Intensive Observing Period

    Data.gov (United States)

    National Aeronautics and Space Administration — The TOGA COARE Data Information System has responsibility for distributing information about TOGA COAREdatasets and access paths.The MAS data are available upon...

  19. Exposure (mAs) optimisation of a multi-detector CT protocol for hepatic lesion detection: are thinner slices better?

    International Nuclear Information System (INIS)

    Dobeli, Karen L.; Lewis, Sarah J.; Meikle, Steven R.; Brennan, Patrick C.; Thiele, David L.

    2014-01-01

    The purpose of this work was to determine the exposure-optimised slice thickness for hepatic lesion detection with CT. A phantom containing spheres (diameter 9.5, 4.8 and 2.4mm) with CT density 10 HU below the background (50 HU) was scanned at 125, 100, 75 and 50 mAs. Data were reconstructed at 5-, 3- and 1-mm slice thicknesses. Noise, contrast-to-noise ratio (CNR), area under the curve (AUC) as calculated using receiver operating characteristic analysis and sensitivity representing lesion detection were calculated and compared. Compared with the 125 mAs/5mm slice thickness setting, significant reductions in AUC were found for 75 mAs (P<0.01) and 50 mAs (P<0.05) at 1- and 3-mm thicknesses, respectively; sensitivity for the 9.5-mm sphere was significantly reduced for 75 (P<0.05) and 50 mAs (P<0.01) at 1-mm thickness; sensitivity for the 4.8-mm sphere was significantly lower for 100, 75 and 50 mAs at all three slice thicknesses (P<0.05). The 2.4-mm sphere was rarely detected. At each slice thickness, noise at 100, 75 and 50 mAs exposures was approximately 10, 30 and 50% higher, respectively, than that at 125 mAs exposure. CNRs decreased in an irregular manner with reductions in exposure and slice thickness. This study demonstrated no advantage to using slices below 5mm thickness, and consequently thinner slices are not necessarily better.

  20. Proton NMR relaxation in hydrous melts

    International Nuclear Information System (INIS)

    Braunstein, J.; Bacarella, A.L.; Benjamin, B.M.; Brown, L.L.; Girard, C.

    1976-01-01

    Pulse and continuous wave NMR measurements are reported for protons in hydrous melts of calcium nitrate at temperatures between -4 and 120 0 C. Although measured in different temperature ranges, spin-lattice (T 1 ) and spin-spin (T 2 ) relaxation times appear to be nearly equal to each other and proportional to the self-diffusion coefficients of solute metal cations such as Cd 2+ . At temperatures near 50 0 C, mean Arrhenius coefficients Δ H/sub T 1 / (kcal/mol) are 7.9, 7.3, and 4.8, respectively, for melts containing 2.8, 4.0, and 8.0 moles of water per mole of calcium nitrate, compared to 4.6 kcal/mol for pure water. Temperature dependence of T 1 and T 2 in Ca(NO 3 ) 2 -2.8 H 2 O between -4 and 120 0 C are non-Arrhenius and can be represented by a Fulcher-type equation with a ''zero mobility temperature'' (T 0 ) of 225 0 K, close to the value of T 0 for solute diffusion, electrical conductance and viscosity. Resolution of the relaxation rates into correlation times for intramolecular (rotational) and intermolecular (translational) diffusional motion is discussed in terms of the Bloembergen-Purcell-Pound and more recent models for dipolar relaxation

  1. Magic-angle-spinning NMR spectroscopy. January 1978-May 1988 (Citations from the INSPEC: Information Services for the Physics and Engineering Communities data base). Report for January 1978-May 1988

    International Nuclear Information System (INIS)

    1988-05-01

    This bibliography contains citations concerning the principles and applications of magic-angle spinning (MAS) nuclear magnetic resonance (NMR) in high-resolution spectra analysis of solids. Magic-angle spinning NMR is a very powerful spectrographic technique for the study of structures, dynamics, and reactivity of solids, and polcrystalline and amorphous solids. Studies of various materials are presented, including zeolites, organic compounds and polymers, liquid crystals, silicate and borate glasses, and alumina and oxide films. Applications in conductive polymers, biological systems, and organic matrixes of composite materials are presented. (Contains 89 citations fully indexed and including a title list.)

  2. El medievalismo fértil de Paloma Díaz-Mas

    Directory of Open Access Journals (Sweden)

    Rafael M. Mérida Jiménez

    2001-01-01

    Full Text Available The author of this article is concerned with trying to understand why Paloma Díaz-Mas, the writer of such an excellent novel as La tierra fértil (1999, has not received much critical attention. He underlines three main reasons. First, she does not live in Madrid or Barcelona and so she is far away from the main centres of cultural power. Second, she teaches Spanish literature in the Basque Country, a political and linguistic community which significantly differs from that of many other writers. Third, she writes historical novels, which does not appear to be very fashionable in Spain these days. Moreover, Díaz-Mas is a woman writer who does not make use of the most commonly available feminine patterns, and she does not seem to offer a model easy to include in a given feminist methodology either. However, Mérida-Jiménez argues that Paloma provides an intelligent deconstruction of “male authority” through subtle rhetorical means, as well as a representation of the weakness of his “domination” in very innovative ways, such as those derived from the dialectics between history and fiction, centrality and marginality, heterosexuality and homosexuality, individual and society, dream and reason or tradition and modernity.

  3. Active and passive fire protection system in academic building KH. Mas Mansur, Islamic University of Indonesia

    Directory of Open Access Journals (Sweden)

    Suryoputro M. Ragil

    2018-01-01

    Full Text Available According to the theory of fire triangle, the existence of combustible materials, heat, and oxygen can cause fire disaster. KH. Mas Mansur building, Islamic University of Indonesia has a fire protection, but rarely to be checked regularly and the number of equipment is less standard as well as the lack of an evacuation route map to facilitate the evacuation process. Inside the building also does not provide safety signs such as the evacuation directions, exit, and warning in case of fire. Therefore, researchers analysed the infrastructure of prevention and control in the building KH. Mas Mansur. Researchers used the method of observation, interviews, and checklist to know the condition directly, and compare with the standard regulations. Results concordance rate of existing infrastructure is 67% fire extinguisher, hydrant box 56%, 71% alarms, sprinkler 0%, 40% detectors, emergency doors 71%, 50% emergency stairs, assembly point 0% and directions 0%. The current results were below the standard of at least 80%. As for recommendations, researchers create a new evacuation map then put the existing infrastructure according to standard regulations, and it had consulted with the specialist of Occupational Safety and Health in the field of fire.

  4. MODELAGEM DE UM SISTEMA MULTIAGENTE DE APOIO À PBL UTILIZANDO A METODOLOGIA MAS-COMMONKADS+

    Directory of Open Access Journals (Sweden)

    Laysa Mabel de Oliveira Fontes

    2014-10-01

    Full Text Available A aprendizagem baseada em problema (Problem-Based Learning - PBL é um método no qual os estudantes aprendem através da resolução de um problema que, em geral, não possui uma solução trivial e uma única solução correta. A PBL destaca o trabalho em equipe como um dos principais requisitos para o sucesso do processo de aprendizagem, ou seja, a colaboração é essencial. No entanto, a implantação de um método de ensino com base na PBL não é uma tarefa trivial. Em Ambientes Virtuais de Aprendizagem (AVAs, a complexidade de implantação deste método é ainda maior, pois o facilitador nem sempre pode detectar possíveis problemas na colaboração, nem possui todas as informações necessárias para aplicar as técnicas de aprendizagem deste método. Desta forma, este artigo apresenta o processo de modelagem de um Sistema Multiagente (SMA de apoio à PBL. O SMA proposto foi modelado utilizando a metodologia MAS-CommonKADS+, que consiste em uma extensão da metodologia MAS-CommonKADS.

  5. ANALISIS PERHITUNGAN DAN PELAPORAN PAJAK PERTAMBAHAN NILAI PADA PT FAJAR MAS KARYATAMA

    Directory of Open Access Journals (Sweden)

    MARINDO PUTRA

    2017-05-01

    Full Text Available Value Added Tax (VAT is Tax that imposed on any apreciation in value of the goods or services in its circulation from producers to consumers. Through the calculation dan reporting is good, then the company may be said it has complied with the applicable rules in order to enhance the national development budget of the Government. PT Fajar Mas Karyatama as a company engaged intrade of goods subject to VAT, as in general make a purchase with Input Tax which may be credited. The purpose of this study to know whether the application of VAT and VAT underpayment or overpayment in accordance with law of VAT No. 42 of 2009. This study used a comparative method. The company will account for and report the delivery of Added Value Tax in the Notice Period of Added Value Tax (VAT Period SPT. VAT calculations made by company are the basis for the report required to implement Tax Laws for the companies. Conclusion is that application of VAT in the calculating and reporting of PT Fajar Mas Karyatama was almost accordance with the VAT Act applied and through the application of VAT, namely the purchase and sale of Taxable Goods so that the sum of the difference by the number of Input Tax or Output Tax generate VAT Less/More Pay at the end each mont, it is accordance with the Law of VAT No. 42 of 2009.

  6. Quality of Milk Pasteurized Produced By UD. Gading Mas During Storage in Refrigerator

    Directory of Open Access Journals (Sweden)

    Manik Eirry Sawitri

    2012-02-01

    Full Text Available The aim of this research was to study pasteurized milk quality produced by UD. Gading Mas on pH, Acidity, alcohol test and TPC during 5 days storage in refrigerator. On first day showed that  weight mass 1,06 (w/w; fat content 2,00 (g/100g,  protein content 3,02  (g/100g, Zn 1,67 ppm, Cu<0,005 ppm, Pb 0,02 ppm,  As  0,0120 ppm, Hg< 0,0002 ppm, Sn 1,60 ppm dan Cd < 0,001 ppm and organoleptic test included color, flavor and taste were normal. Pasteurized milk characteristic during 5 days refrigeration for pH were 6,57;6,58;6,73;6,60 and 6,50 respectively. Acidity were 1,147 %, 0,145 %, 0,145%, 0,157 %, 0,156 % and 0,175  % respectively. TPC were 6,16 x 101, 1,2. 104; 3,15.104, 0,42.106 and 3,5.108 respectively. It concluded that pasteurized milk produced by UD Gading Mas fulfilled SNI quality standard based on weight mass, pH, acidity, fat, protein, heavy metal content, organoleptic test and TPC.   Keywords: pasteurized milk, quality, refrigerator

  7. Genotyping by sequencing (GBS, an ultimate marker-assisted selection (MAS tool to accelerate plant breeding

    Directory of Open Access Journals (Sweden)

    Jiangfeng eHe

    2014-09-01

    Full Text Available Marker-assisted selection (MAS refers to the use of molecular markers to assist phenotypic selections in crop improvement. Several types of molecular markers, such as single nucleotide polymorphism (SNP, have been identified and effectively used in plant breeding. The application of next-generation sequencing (NGS technologies has led to remarkable advances in whole genome sequencing, which provides ultra-throughput sequences to revolutionize plant genotyping and breeding. To further broaden NGS usages to large crop genomes such as maize and wheat, genotyping by sequencing (GBS has been developed and applied in sequencing multiplexed samples that combine molecular marker discovery and genotyping. GBS is a novel application of NGS protocols for discovering and genotyping SNPs in crop genomes and populations. The GBS approach includes the digestion of genomic DNA with restriction enzymes followed by the ligation of barcode adapter, PCR amplification and sequencing of the amplified DNA pool on a single lane of flow cells. Bioinformatic pipelines are needed to analyze and interpret GBS datasets. As an ultimate MAS tool and a cost-effective technique, GBS has been successfully used in implementing genome-wide association study (GWAS, genomic diversity study, genetic linkage analysis, molecular marker discovery and genomic selection (GS under a large scale of plant breeding programs.

  8. Elektroniskās naudas sistēmas WebMoney

    OpenAIRE

    Zablocka, Jelena

    2011-01-01

    Šī darba mērķis ir pamatojoties uz speciālo literatūru un pieejamu statistisko informāciju izskatīt jautājumu par elektroniskās naudas būtību, raksturot un parādīt tās veidus, analizēt un izskatīt elektroniskās naudas izmantošanas problēmas, izpētīt un norādīt tās izmantošanas perspektīvas, novērtēt tās uzskaites un kontroles operāciju problēmas, kas ir sastopamas, izmantojot elektronisko naudu praksē. Darbs sastāv no 5 nodaļām. Pirmajā nodaļā aplūkoti elektroniskās naudas jēdziens un ...

  9. Genotype evaluation of cowpea seeds (Vigna unguiculata) using 1H qNMR combined with exploratory tools and solid-state NMR.

    Science.gov (United States)

    Alves Filho, Elenilson G; Silva, Lorena M A; Teofilo, Elizita M; Larsen, Flemming H; de Brito, Edy S

    2017-01-01

    The ultimate aim of this study was to apply a non-targeted chemometric analysis (principal component analysis and hierarchical clustering analysis using the heat map approach) of NMR data to investigate the variability of organic compounds in nine genotype cowpea seeds, without any complex pre-treatment. In general, both exploratory tools show that Tvu 233, CE-584, and Setentão genotypes presented higher amount mainly of raffinose and Tvu 382 presented the highest content of choline and least content of raffinose. The evaluation of the aromatic region showed the Setentão genotype with highest content of niacin/vitamin B3 whereas Tvu 382 with lowest amount. To investigate rigid and mobile components in the seeds cotyledon, 13 C CP and SP/MAS solid-state NMR experiments were performed. The cotyledon of the cowpea comprised a rigid part consisting of starch as well as a soft portion made of starch, fatty acids, and protein. The variable contact time experiment suggests the presence of lipid-amylose complexes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Identification of the silver state in the framework of Ag-containing zeolite by XRD, FTIR, photoluminescence, 109Ag NMR, EPR, DR UV-vis, TEM and XPS investigations.

    Science.gov (United States)

    Popovych, Nataliia; Kyriienko, Pavlo; Soloviev, Sergiy; Baran, Rafal; Millot, Yannick; Dzwigaj, Stanislaw

    2016-10-26

    Silver has been identified in the framework of Ag x SiBEA zeolites (where x = 3-6 Ag wt%) by the combined use of XRD, 109 Ag MAS NMR, FTIR, diffuse reflectance UV-visible, EPR and XPS spectroscopy. The incorporation of Ag ions into the framework of SiBEA zeolite has been evidenced by XRD. The consumption of OH groups as a result of their reaction with the silver precursor has been monitored by FTIR and photoluminescence spectroscopy. The changes in the silver state as a function of Ag content and thermal and hydrogen treatment at 573 K have been identified by 109 Ag MAS NMR, EPR, DR UV-visible, TEM and XPS investigations. The acidity of AgSiBEA has been investigated by FTIR spectroscopy of adsorbed CO and pyridine used as probe molecules.

  11. Reducing acquisition times in multidimensional NMR with a time-optimized Fourier encoding algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhiyong [Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100 (Israel); Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, Fujian 361005 (China); Smith, Pieter E. S.; Frydman, Lucio, E-mail: lucio.frydman@weizmann.ac.il [Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100 (Israel)

    2014-11-21

    Speeding up the acquisition of multidimensional nuclear magnetic resonance (NMR) spectra is an important topic in contemporary NMR, with central roles in high-throughput investigations and analyses of marginally stable samples. A variety of fast NMR techniques have been developed, including methods based on non-uniform sampling and Hadamard encoding, that overcome the long sampling times inherent to schemes based on fast-Fourier-transform (FFT) methods. Here, we explore the potential of an alternative fast acquisition method that leverages a priori knowledge, to tailor polychromatic pulses and customized time delays for an efficient Fourier encoding of the indirect domain of an NMR experiment. By porting the encoding of the indirect-domain to the excitation process, this strategy avoids potential artifacts associated with non-uniform sampling schemes and uses a minimum number of scans equal to the number of resonances present in the indirect dimension. An added convenience is afforded by the fact that a usual 2D FFT can be used to process the generated data. Acquisitions of 2D heteronuclear correlation NMR spectra on quinine and on the anti-inflammatory drug isobutyl propionic phenolic acid illustrate the new method's performance. This method can be readily automated to deal with complex samples such as those occurring in metabolomics, in in-cell as well as in in vivo NMR applications, where speed and temporal stability are often primary concerns.

  12. NMR studies of stock process water and reaction pathways in hydrothermal carbonization of furfural residue

    Directory of Open Access Journals (Sweden)

    Fen Yue

    2018-04-01

    Full Text Available Hydrothermal carbonization (HTC is a valuable approach to convert furfural residue (FR into carbon material. The prepared biochars are usually characterized comprehensively, while the stock process water still remains to be studied in detail. Herein, a NMR study of the main components in stock process water generated at different HTC reaction conditions was reported. Various qualitative and quantitative NMR techniques (1H and 13C NMR, 1H–1H COSY and 1H13C HSQC etc. especially 1D selective gradient total correlation spectroscopy (TOCSY NMR were strategically applied in the analysis of HTC stock process water. Without separation and purification, it was demonstrated that the main detectable compounds are 5-hydroxymethylfurfural, formic acid, methanol, acetic acid, levulinic acid, glycerol, hydroxyacetone and acetaldehyde in this complicate mixture. Furthermore, the relationship between the concentration of major products and the reaction conditions (180–240 °C at 8 h, and 1–24 h at 240 °C was established. Finally, reasonable reaction pathways for hydrothermal conversion of FR were proposed based on this result and our previously obtained characteristics of biochars. The routine and challenging NMR methods utilized here would be an alternative other than HPLC or GC for biomass conversion research and can be extended to more studies. Keywords: NMR, Hydrothermal carbonization, Furfural residue, Stock process water

  13. In-cell NMR spectroscopy of proteins inside Xenopus laevis oocytes

    International Nuclear Information System (INIS)

    Sakai, Tomomi; Tochio, Hidehito; Tenno, Takeshi; Ito, Yutaka; Kokubo, Tetsuro; Hiroaki, Hidekazu; Shirakawa, Masahiro

    2006-01-01

    In-cell NMR is an application of solution NMR that enables the investigation of protein conformations inside living cells. We have measured in-cell NMR spectra in oocytes from the African clawed frog Xenopus laevis. 15 N-labeled ubiquitin, its derivatives and calmodulin were injected into Xenopus oocytes and two-dimensional 1 H- 15 N correlation spectra of the proteins were obtained. While the spectrum of wild-type ubiquitin in oocytes had rather fewer cross-peaks compared to its in vitro spectrum, ubiquitin derivatives that are presumably unable to bind to ubiquitin-interacting proteins gave a markedly larger number of cross-peaks. This observation suggests that protein-protein interactions between ubiquitin and ubiquitin-interacting proteins may cause NMR signal broadening, and hence spoil the quality of the in-cell HSQC spectra. In addition, we observed the maturation of ubiquitin precursor derivative in living oocytes using the in-cell NMR technique. This process was partly inhibited by pre-addition of ubiquitin aldehyde, a specific inhibitor for ubiquitin C-terminal hydrolase (UCH). Our work demonstrates the potential usefulness of in-cell NMR with Xenopus oocytes for the investigation of protein conformations and functions under intracellular environmental conditions

  14. Reducing acquisition times in multidimensional NMR with a time-optimized Fourier encoding algorithm

    International Nuclear Information System (INIS)

    Zhang, Zhiyong; Smith, Pieter E. S.; Frydman, Lucio

    2014-01-01

    Speeding up the acquisition of multidimensional nuclear magnetic resonance (NMR) spectra is an important topic in contemporary NMR, with central roles in high-throughput investigations and analyses of marginally stable samples. A variety of fast NMR techniques have been developed, including methods based on non-uniform sampling and Hadamard encoding, that overcome the long sampling times inherent to schemes based on fast-Fourier-transform (FFT) methods. Here, we explore the potential of an alternative fast acquisition method that leverages a priori knowledge, to tailor polychromatic pulses and customized time delays for an efficient Fourier encoding of the indirect domain of an NMR experiment. By porting the encoding of the indirect-domain to the excitation process, this strategy avoids potential artifacts associated with non-uniform sampling schemes and uses a minimum number of scans equal to the number of resonances present in the indirect dimension. An added convenience is afforded by the fact that a usual 2D FFT can be used to process the generated data. Acquisitions of 2D heteronuclear correlation NMR spectra on quinine and on the anti-inflammatory drug isobutyl propionic phenolic acid illustrate the new method's performance. This method can be readily automated to deal with complex samples such as those occurring in metabolomics, in in-cell as well as in in vivo NMR applications, where speed and temporal stability are often primary concerns

  15. Theoretical and experimental NMR studies on muscimol from fly agaric mushroom (Amanita muscaria)

    Science.gov (United States)

    Kupka, Teobald; Wieczorek, Piotr P.

    2016-01-01

    In this article we report results of combined theoretical and experimental NMR studies on muscimol, the bioactive alkaloid from fly agaric mushroom (Amanita muscaria). The assignment of 1H and 13C NMR spectra of muscimol in DMSO-d6 was supported by additional two-dimensional heteronuclear correlated spectra (2D NMR) and gauge independent atomic orbital (GIAO) NMR calculations using density functional theory (DFT). The effect of solvent in theoretical calculations was included via polarized continuum model (PCM) and the hybrid three-parameter B3LYP density functional in combination with 6-311++G(3df,2pd) basis set enabled calculation of reliable structures of non-ionized (neutral) molecule and its NH and zwitterionic forms in the gas phase, chloroform, DMSO and water. GIAO NMR calculations, using equilibrium and rovibrationally averaged geometry, at B3LYP/6-31G* and B3LYP/aug-cc-pVTZ-J levels of theory provided muscimol nuclear magnetic shieldings. The theoretical proton and carbon chemical shifts were critically compared with experimental NMR spectra measured in DMSO. Our results provide useful information on its structure in solution. We believe that such data could improve the understanding of basic features of muscimol at atomistic level and provide another tool in studies related to GABA analogs.

  16. Two-Dimensional NMR Evidence for Cleavage of Lignin and Xylan Substituents in Wheat Straw Through Hydrothermal Pretreatment and Enzymatic Hydrolysis

    Science.gov (United States)

    Daniel J. Yelle; Prasad Kaparaju; Christopher G. Hunt; Kolby Hirth; Hoon Kim; John Ralph; Claus Felby

    2012-01-01

    Solution-state two-dimensional (2D) nuclear magnetic resonance (NMR) spectroscopy of plant cell walls is a powerful tool for characterizing changes in cell wall chemistry during the hydrothermal pretreatment process of wheat straw for second-generation bioethanol production. One-bond 13C-1H NMR correlation spectroscopy, via...

  17. Accessible surface area from NMR chemical shifts

    Energy Technology Data Exchange (ETDEWEB)

    Hafsa, Noor E.; Arndt, David; Wishart, David S., E-mail: david.wishart@ualberta.ca [University of Alberta, Department of Computing Science (Canada)

    2015-07-15

    Accessible surface area (ASA) is the surface area of an atom, amino acid or biomolecule that is exposed to solvent. The calculation of a molecule’s ASA requires three-dimensional coordinate data and the use of a “rolling ball” algorithm to both define and calculate the ASA. For polymers such as proteins, the ASA for individual amino acids is closely related to the hydrophobicity of the amino acid as well as its local secondary and tertiary structure. For proteins, ASA is a structural descriptor that can often be as informative as secondary structure. Consequently there has been considerable effort over the past two decades to try to predict ASA from protein sequence data and to use ASA information (derived from chemical modification studies) as a structure constraint. Recently it has become evident that protein chemical shifts are also sensitive to ASA. Given the potential utility of ASA estimates as structural constraints for NMR we decided to explore this relationship further. Using machine learning techniques (specifically a boosted tree regression model) we developed an algorithm called “ShiftASA” that combines chemical-shift and sequence derived features to accurately estimate per-residue fractional ASA values of water-soluble proteins. This method showed a correlation coefficient between predicted and experimental values of 0.79 when evaluated on a set of 65 independent test proteins, which was an 8.2 % improvement over the next best performing (sequence-only) method. On a separate test set of 92 proteins, ShiftASA reported a mean correlation coefficient of 0.82, which was 12.3 % better than the next best performing method. ShiftASA is available as a web server ( http://shiftasa.wishartlab.com http://shiftasa.wishartlab.com ) for submitting input queries for fractional ASA calculation.

  18. 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)

  19. Increasing brain angiotensin converting enzyme 2 activity decreases anxiety-like behavior in male mice by activating central Mas receptors.

    Science.gov (United States)

    Wang, Lei; de Kloet, Annette D; Pati, Dipanwita; Hiller, Helmut; Smith, Justin A; Pioquinto, David J; Ludin, Jacob A; Oh, S Paul; Katovich, Michael J; Frazier, Charles J; Raizada, Mohan K; Krause, Eric G

    2016-06-01

    Over-activation of the brain renin-angiotensin system (RAS) has been implicated in the etiology of anxiety disorders. Angiotensin converting enzyme 2 (ACE2) inhibits RAS activity by converting angiotensin-II, the effector peptide of RAS, to angiotensin-(1-7), which activates the Mas receptor (MasR). Whether increasing brain ACE2 activity reduces anxiety by stimulating central MasR is unknown. To test the hypothesis that increasing brain ACE2 activity reduces anxiety-like behavior via central MasR stimulation, we generated male mice overexpressing ACE2 (ACE2 KI mice) and wild type littermate controls (WT). ACE2 KI mice explored the open arms of the elevated plus maze (EPM) significantly more than WT, suggesting increasing ACE2 activity is anxiolytic. Central delivery of diminazene aceturate, an ACE2 activator, to C57BL/6 mice also reduced anxiety-like behavior in the EPM, but centrally administering ACE2 KI mice A-779, a MasR antagonist, abolished their anxiolytic phenotype, suggesting that ACE2 reduces anxiety-like behavior by activating central MasR. To identify the brain circuits mediating these effects, we measured Fos, a marker of neuronal activation, subsequent to EPM exposure and found that ACE2 KI mice had decreased Fos in the bed nucleus of stria terminalis but had increased Fos in the basolateral amygdala (BLA). Within the BLA, we determined that ∼62% of GABAergic neurons contained MasR mRNA and expression of MasR mRNA was upregulated by ACE2 overexpression, suggesting that ACE2 may influence GABA neurotransmission within the BLA via MasR activation. Indeed, ACE2 overexpression was associated with increased frequency of spontaneous inhibitory postsynaptic currents (indicative of presynaptic release of GABA) onto BLA pyramidal neurons and central infusion of A-779 eliminated this effect. Collectively, these results suggest that ACE2 may reduce anxiety-like behavior by activating central MasR that facilitate GABA release onto pyramidal neurons within the

  20. 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