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Sample records for 33s mas nmr

  1. Sensitivity enhancement in natural-abundance solid-state 33S MAS NMR spectroscopy employing adiabatic inversion pulses to the satellite transitions

    Hansen, Michael Ryan; Brorson, Michael; Bildsøe, Henrik; Skibsted, Jørgen; Jakobsen, Hans J.

    2008-02-01

    The WURST (wideband uniform rate smooth truncation) and hyperbolic secant (HS) pulse elements have each been employed as pairs of inversion pulses to induce population transfer (PT) between the four energy levels in natural abundance solid-state 33S (spin I = 3/2) MAS NMR, thereby leading to a significant gain in intensity for the central transition (CT). The pair of inversion pulses are applied to the satellite transitions for a series of inorganic sulfates, the sulfate ions in the two cementitious materials ettringite and thaumasite, and the two tetrathiometallates (NH 4) 2WS 4 and (NH 4) 2MoS 4. These materials all exhibit 33S quadrupole coupling constants ( CQ) in the range 0.1-1.0 MHz, with precise CQ values being determined from analysis of the PT enhanced 33S MAS NMR spectra. The enhancement factors for the WURST and HS elements are quite similar and are all in the range 1.74-2.25 for the studied samples, in excellent agreement with earlier reports on HS enhancement factors (1.6-2.4) observed for other spin I = 3/2 nuclei with similar CQ values (0.3-1.2 MHz). Thus, a time saving in instrument time by a factor up to five has been achieved in natural abundance 33S MAS NMR, a time saving which is extremely welcome for this important low-γ nucleus.

  2. Detection of Taurine in Biological Tissues by 33S NMR Spectroscopy

    Musio, Roberta; Sciacovelli, Oronzo

    2001-12-01

    The potential of 33S NMR spectroscopy for biochemical investigations on taurine (2-aminoethanesulfonic acid) is explored. It is demonstrated that 33S NMR spectroscopy allows the selective and unequivocal identification of taurine in biological samples. 33S NMR spectra of homogenated and intact tissues are reported for the first time, together with the spectrum of a living mollusc. Emphasis is placed on the importance of choosing appropriate signal processing methods to improve the quality of the 33S NMR spectra of biological tissues.

  3. 33S NMR cryogenic probe for taurine detection

    Hobo, Fumio; Takahashi, Masato; Maeda, Hideaki

    2009-03-01

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

  4. Structural biology applications of solid state MAS DNP NMR

    Akbey, Ümit; Oschkinat, Hartmut

    2016-08-01

    Dynamic Nuclear Polarization (DNP) has long been an aim for increasing sensitivity of nuclear magnetic resonance (NMR) spectroscopy, delivering spectra in shorter experiment times or of smaller sample amounts. In recent years, it has been applied in magic angle spinning (MAS) solid-state NMR to a large range of samples, including biological macromolecules and functional materials. New research directions in structural biology can be envisaged by DNP, facilitating investigations on very large complexes or very heterogeneous samples. Here we present a summary of state of the art DNP MAS NMR spectroscopy and its applications to structural biology, discussing the technical challenges and factors affecting DNP performance.

  5. 31P Solid-state MAS NMR spectra

    The structures of the silicoaluminiophosphates MCM-1 and MCM9 were characterized by 27Al and 31P MAS NMR. The structural identity of MCM-1 and its silicon-free homologue AlPO4-H3 is demonstrated. The presence of a structural mixture in MCM-9 is confirmed. 31P MAS NMR spectra of MCM-9 could be interpreted as a superposition of spectra of VPI-5, AlPO4-H3 and SAPO-11 phases. (author). 12 refs.; 3 figs.; 1 tab

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

    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.

  7. Magic-angle-spinning NMR (MAS-NMR) spectroscopy and the structure of zeolites

    After outlining the chemical features and properties which make zeolites such an important group of catalysts and sorbents, the article explains how high-resolution solid-state NMR with magic-angle spinning reveals numerous new insights into their structure. 29Si-MAS-NMR readily and quantitatively identifies five distinct Si(OAl)sub(n)(OSi)sub(4-n) structural groups in zeolitic frameworks (n=0,1,...4), corresponding to the first tetrahedral coordination shell of a silicon atom. Many catalytic and other chemical properties of zeolites are governed by the short-range Si, Al order, the nature of which is greatly clarified by 29Si-MAS-NMR. (orig./EF)

  8. 1H MAS, 13C CP/MAS, and 2H NMR spectra studies of piperidinium p-chlorobenzoate

    Anomalous H/D isotope effects were detected in the 1H MAS NMR spectra of piperidinium p-chlorobenzoate (C5H10NH 2+⋅ ClC6H4COO − ) upon deuterium substitution of hydrogen atoms which form two kinds of N-H⋯O H-bonds in the crystal; in contrast to these spectra, only slight chemical shifts were recorded in 13C CP/MAS NMR spectra. 2H NMR spectrum of the deuterated sample show quadrupole coupling constants of 148 and 108 kHz, and reveal that there are a few motions contributing to the electric-field modulation of the 2H nucleus. The 1H MAS NMR spectra of piperidinium p-chlrobenzoate-d16 (C5D10ND 2+⋅ ClC6D4COO − ) and -d14 (C5D10NH 2+⋅ ClC6D4COO − ) revealed that the change in the envelope is caused by chemical shifts of each signal upon deuteration. Calculations based on the density-functional-theory showed that the N-H distance along the crystallographic a-axis mainly contributes to the anomalous isotope effects on 1H MAS NMR envelopes.

  9. Sealed rotors for in situ high temperature high pressure MAS NMR

    Hu, Jian Z. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hu, Mary Y. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Zhao, Zhenchao [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Xu, Souchang [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Vjunov, Aleksei [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Shi, Hui [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Camaioni, Donald M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Peden, Charles H. F. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lercher, Johannes A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-07-06

    Magic angle spinning (MAS) nuclear magnetic resonance (NMR) investigations on heterogeneous samples containing solids, semi-solids, liquid and gases or a mixture of them under non-conventional conditions of a combined high pressure and high temperature, or cold temperature suffer from the unavailability of a perfectly sealed rotor. Here, we report the design of reusable and perfectly-sealed all-zircornia MAS rotors. The rotors are easy to use and are suitable for operation temperatures from below 0 to 250 °C and pressures up to 100 bar. As an example of potential applications we performed in situ MAS NMR investigations of AlPO₄-5 molecular sieve crystallization, a kinetic study of the cyclohexanol dehydration reaction using 13C MAS NMR, and an investigation of the metabolomics of intact biological tissue at low temperature using 1H HR-MAS NMR spectroscopy. The in situ MAS NMR experiments performed using the reported rotors allowed reproduction of the results from traditional batch reactions, while offering more detailed quantitative information at the molecular level, as demonstrated for the molecular sieve synthesis and activation energy measurements for cyclohexanol dehydration. The perfectly sealed rotor also shows promising application for metabolomics studies using 1H HR-MAS NMR.

  10. {sup 29}Si MAS NMR for the zeolite Y - gallium oxide system; {sup 29}Si mas NMR dla ukladu fojazyt-tlenek galu

    Sulikowski, B.; Derewinski, M. [Inst. Katalizy i Fizykochemii Powierzchni, Polska Akademia Nauk, Cracow (Poland); Olejniczak, Z.; Segnowski, S. [Institute of Nuclear Physics, Cracow (Poland)

    1994-12-31

    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 {sup 29}Si has been described and discussed. 11 refs, 4 figs, 2 tabs.

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

    Stevens, Tim J.; Fogh, Rasmus H.; Boucher, Wayne [University of Cambridge, Department of Biochemistry (United Kingdom); Higman, Victoria A. [University of Oxford, Department of Biochemistry (United Kingdom); Eisenmenger, Frank; Bardiaux, Benjamin; Rossum, Barth-Jan van; Oschkinat, Hartmut [Leibniz-Institut fuer Molekulare Pharmakologie, Department of Structural Biology (Germany); Laue, Ernest D., E-mail: e.d.laue@bioc.cam.ac.uk [University of Cambridge, Department of Biochemistry (United Kingdom)

    2011-12-15

    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.

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

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

    2011-12-01

    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. PMID:21953355

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

    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.

  14. Cp-MAS solid state NMR of secondary metabolites from northeastern Brazil plants

    Aiming to learn more about the 13 C NMR of secondary metabolites in the solid state, as well as to make use of the Cp-MAS probe available in the CENAUREMN (Northeastern Center for Application and Use od NMR) laboratory, an analysis has been performed on the the following six classes of secondary metabolites: diterpenes, coumarins, alkaloids, flavonoids and purines

  15. 29Si and 27Al MAS NMR spectra of mullites from different kaolinites.

    He, Hongping; Guo, Jiugao; Zhu, Jianxi; Yuan, Peng; Hu, Cheng

    2004-04-01

    Mullites synthesized from four kaolinites with different random defect densities have been studied by 27Al and 29Si magic angle spinning nuclear magnetic resonance spectroscopy (MAS NMR) and X-ray diffraction (XRD). All these mullites show the same XRD pattern. However, 29Si and 27Al MAS NMR spectra reveal that the mullites derived from kaolinites with high defect densities, have a sillimanite-type Al/Si ordering scheme and are low in silica, whereas those mullites derived from kaolinites with low defect densities, consist of both sillimanite- and mullite-type Al/Si ordering schemes and are rich in silica. PMID:15084323

  16. Advanced instrumentation for DNP-enhanced MAS NMR for higher magnetic fields and lower temperatures

    Matsuki, Yoh; Idehara, Toshitaka; Fukazawa, Jun; Fujiwara, Toshimichi

    2016-03-01

    Sensitivity enhancement of MAS NMR using dynamic nuclear polarization (DNP) is gaining importance at moderate fields (B0 90 K) with potential applications in chemistry and material sciences. However, considering the ever-increasing size and complexity of the systems to be studied, it is crucial to establish DNP under higher field conditions, where the spectral resolution and the basic NMR sensitivity tend to improve. In this perspective, we overview our recent efforts on hardware developments, specifically targeted on improving DNP MAS NMR at high fields. It includes the development of gyrotrons that enable continuous frequency tuning and rapid frequency modulation for our 395 GHz-600 MHz and 460 GHz-700 MHz DNP NMR spectrometers. The latter 700 MHz system involves two gyrotrons and a quasi-optical transmission system that combines two independent sub-millimeter waves into a single dichromic wave. We also describe two cryogenic MAS NMR probe systems operating, respectively, at T ∼100 K and ∼30 K. The latter system utilizes a novel closed-loop helium recirculation mechanism, achieving cryogenic MAS without consuming any cryogen. These instruments altogether should promote high-field DNP toward more efficient, reliable and affordable technology. Some experimental DNP results obtained with these instruments are presented.

  17. A solid state MAS NMR study of the thermal reactions in alkali-leached aluminosilicates

    The thermal transformations of aluminosilicate minerals such as kaolinite (Al2Si2O5(OH)4) are of importance for the production of both clay-based ceramics and high-technology ceramics such as sialons. Solid-state MAS NMR can provide information about the intermediate stages in the formation of mullite (Al6Si2O13). These intermediates, which are only poorly crystalline and less amenable to XRD study, may include poorly crystalline mullite, a cubic spinel similar to γ-Al2O3 but which has been suggested to contain Si, and other amorphous aluminosilicate phases of variable composition. Since the 29Si and 27Al MAS NMR spectra of all these phases are expected to contain resonances broadly in the same spectral area, unambiguous differentiation of these phases has not so far proved possible by this technique. The work reported here was suggested by the possibility of selective alkali extraction of some of the more silica-rich phases using techniques developed by Chakravorty and Ghosh, which was hoped to reveal the MAS NMR features of the less-leachable phases. NMR study of the leached products after subsequent thermal treatment also provided useful information about the leaching reactions themselves. Copyright (1999) Australasian Ceramic Society

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

    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.

  19. (11)B MAS NMR and First-Principles Study of the [OBO3] Pyramids in Borates.

    Zhou, Bing; Sun, Wei; Zhao, Biao-Chun; Mi, Jin-Xiao; Laskowski, Robert; Terskikh, Victor; Zhang, Xi; Yang, Lingyun; Botis, Sanda M; Sherriff, Barbara L; Pan, Yuanming

    2016-03-01

    Borates are built from the [Bϕ3] planar triangles and the [Bϕ4] tetrahedral groups, where ϕ denotes O or OH. However, the [Bϕ4] groups in some borates are highly distorted to include three normal B-O bonds and one anomalously long B-O bond and, therefore, are best described as the [OBO3] pyramids. Four synthetic borates of the boracite-type structures (Mg3B7O13Br, Cu3B7O13Br, Zn3B7O13Cl, and Mg3B7O13Cl) containing a range of [OBO3] pyramids were investigated by multifield (7.05, 14.1, and 21.1 T) (11)B magic-angle spinning nuclear magnetic resonance (MAS NMR), triple quantum (3Q) MAS NMR experiments, as well as density functional theory calculations. The high-resolution (11)B MAS NMR spectra supported by theoretical predictions show that the [OBO3] pyramids are characterized by isotropic chemical shifts δiso((11)B) from 1.4(1) to 4.9(1) ppm and nuclear quadrupole parameters CQ((11)B) up to 1.3(1) MHz, both significantly different from those of the [BO4] and [BO3] groups in borates. These δiso((11)B) and CQ((11)B) values indicate that the [OBO3] pyramids represent an intermediate state between the [BO4] tetrahedra and [BO3] triangles and demonstrate that the (11)B NMR parameters of four-coordinate boron oxyanions are sensitive to local structural environments. The orientation of the calculated unique electronic field gradient tensor element Vzz of the [OBO3] pyramids is aligned approximately along the direction of the anomalously long B-O bond, corresponding to B-2pz with the lowest electron density. PMID:26914372

  20. Bulk carbohydrate grain filling of barley ß-glucan mutants studied by 1H HR MAS NMR

    Seefeldt, Helene Fast; Larsen, Flemming Hofmann; Viereck, Nanna;

    2008-01-01

    Temporal and genotypic differences in bulk carbohydrate accumulation in three barley genotypes differing in the content of mixed linkage β-(1→3),(1→4)-D-glucan (β-glucan) and starch were investigated using proton high-resolution, magic angle spinning, nuclear magnetic resonance (1H HR MAS NMR......) during grain filling. For the first time, 1H HR MAS NMR spectra of flour from immature barley seeds are analyzed. Spectral assignments are made using two-dimensional (2D) NMR methods. Both α- and β-glucan biosynthesis were characterized by inspection of the spectra as well as by calibration to the...

  1. 31P MAS-NMR of human erythrocytes: independence of cell volume from angular velocity.

    Kuchel, P W; Bubb, W A; Ramadan, S; Chapman, B E; Philp, D J; Coen, M; Gready, J E; Harvey, P J; McLean, A J; Hook, J

    2004-09-01

    31P magic angle spinning NMR (MAS-NMR) spectra were obtained from suspensions of human red blood cells (RBCs) that contained the cell-volume-sensitive probe molecule, dimethyl methylphosphonate (DMMP). A mathematical representation of the spectral-peak shape, including the separation and width-at-half-height in the 31P NMR spectra, as a function of rotor speed, enabled us to explore the extent to which a change in cell volume would be reflected in the spectra if it occurred. We concluded that a fractional volume change in excess of 3% would have been detected by our experiments. Thus, the experiments indicated that the mean cell volume did not change by this amount even at the highest spinning rate of 7 kHz. The mean cell volume and intracellular 31P line-width were independent of the packing density of the cells and of the initial cell volume. The relationship of these conclusions to other non-NMR studies of pressure effects on cells is noted. PMID:15334588

  2. Raman and 31P MAS NMR spectroscopic studies of lead phosphate glasses containing thorium oxide

    (PbO)0.5(P2O5)0.5 glasses in which part of the PbO/ P2O5 was replaced by ThO2 up to 10 mol% have been prepared by conventional melt quench method and characterized by Raman and 31P MAS NMR spectroscopic studies. Raman studies of these samples clearly revealed the existence of PO4 structural units having two non bridging oxygen atoms attached to phosphorus (PO22-). The 31P MAS NMR studies indicated the presence of two types of phosphorus structural units in both PbO -P2O5 and PbO-P2O5-ThO2 glasses, namely Q2 and Q1 (PO4 structural units with 2 and 1 bridging oxygen atoms respectively). Increase in the concentration of ThO2 at the expense of both PbO/P2O5 has been found to result in the increased amount of Q1 structural units of phosphorus, indicating that ThO2 acts as only a network modifier. ThO2 has been found to form the glassy phase with PbO-P2O5 system only up to 10 mol%. (author)

  3. Structural analysis of molybdo-zinc-phosphate glasses: Neutron scattering, FTIR, Raman scattering, MAS NMR studies

    Renuka, C.; Shinde, A. B.; Krishna, P. S. R.; Reddy, C. Narayana

    2016-08-01

    Vitreous samples were prepared in the xMoO3-17ZnO-(83-x) NaPO3 with 35 ≥ x ≥ 55 glass forming system by energy efficient microwave heating method. Structural evolution of the vitreous network was monitored as a function of composition by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), Raman scattering, Magic Angle Spin Nuclear magnetic resonance (MAS NMR) and Neutron scattering. Addition of MoO3 to the ZnO-NaPO3 glass leads to a pronounced increase in glass transition temperature (Tg) suggesting a significant increase in network connectivity and strength. In order to analyze FTIR and Raman scattering, a simple structural model is presented to rationalize the experimental observations. A number of structural units are formed due to network modification, and the resulting glass may be characterized by a network polyhedral with different numbers of unshared corners. 31P MAS NMR confirms a clear distinction between structural species having 3, 2, 1, 0 bridging oxygens (BOs). Further, Neutron scattering studies were used to probe the structure of these glasses. The result suggests that all the investigated glasses have structures based on chains of four coordinated phosphate and six coordinated molybdate units, besides, two different lengths of P-O bonds in tetrahedral phosphate units that are assigned to bonds of the P-atom with terminal and bridging oxygen atoms.

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

    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 13C line widths and <0.5 ppm 15N 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

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

    Eddy, Matthew T. [The Scripps Research Institute, Department of Integrative Structural and Computational Biology (United States); Su, Yongchao; Silvers, Robert; Andreas, Loren; Clark, Lindsay [Massachusetts Institute of Technology, Department of Chemistry (United States); Wagner, Gerhard [Harvard Medical School, Department of Biological Chemistry and Molecular Pharmacology (United States); Pintacuda, Guido; Emsley, Lyndon [Université de Lyon, Centre de RMN à Très Hauts Champs, Institut des Sciences Analytiques (CNRS, ENS Lyon, UCB Lyon 1) (France); Griffin, Robert G., E-mail: rgg@mit.edu [Massachusetts Institute of Technology, Department of Chemistry (United States)

    2015-04-15

    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 {sup 13}C line widths and <0.5 ppm {sup 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

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

    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.

  7. Study of Surface Modification Mechanism of Calcined Kaolin by MAS NMR

    杨晓杰; 邓飞皇; 张蓓

    2002-01-01

    The 29Si and 27Al in modified and unmodified calcined kaolin were res earched and compared by using MAS NMR. The result shows that the chemical shift of -106×10-6 of 29Si almost keeps unchanged after being modifie d, but 27Al cha nges obviously. The chemical shift of 5.44×10-6 and 65.69×10-6 of 27Al are sep arately shifted to 3.8×10-6-4.4×10-6 and 54.6×10-6-59.9×1 0-6 after being mod ified. And the chemical modification of kaolin is completed by linking with Al o n the surface of it.

  8. 1H MAS NMR spectra of hy- droxyl species on diatomite surface

    2001-01-01

    High spinning speed 1H magic-angle spinning nuclear magnetic resonance (1H MAS NMR) was used to detect surface hydroxyl groups of diatomite, which include isolated hydroxyl groups and hydrogen-bonded hydroxyl groups, and water adsorbed on diatomite surface that include pore water and hydrogen-bonded water. The corresponding proton chemical shifts of above species are ca. 2.0, 6.0-7.1, 4.9 and 3.0 respectively. Accompanied by thermal treatment temperature ascending, the pore water and hydrogen-bonded water are desorbed successively. As a result, the relative intensities of the peaks assigned to protons of isolat-ed hydroxyl groups and hydrogen-bonded hydroxyl groups increase gradually and reach their maxima at 1000℃. After 1100℃ calcination, the hydroxyl groups that classified to strongly hydrogen-bonded ones and the isolated hydroxyl groups condense basically. But some weakly hydrogen-bonded hydroxyl groups may still persist in the micropores.

  9. The structural environments of cations adsorbed onto clays: A 133CsMAS NMR spectroscopic study

    Chapter One investigates the local structural environment of adsorbed cations on the mineral hectorite using 133Ca Variable-Temperature Magic-Angle-Spinning Nuclear Magnetic Resonance (VT-MAS NMR) spectroscopy. The results show that Cs on hectorite occurs in several distinctly different chemical environments, and that motional averaging of Ca between some of these sites occurs above ∼-40 degree C if water is present in the interlayer. Above ∼-10 degree C, spectra for slurries of hectorite in CsCl solutions yield two peaks, one due to Cs in solution, and the other due to Cs motionally-averaged on the clay. Below ∼-60 degree C, motional averaging of the adsorbed Cs slows sufficiently to allow resolution of two peaks representing different Cs-environments on the clay. The Stern-Gouy model is employed to explain these peaks and assign one to Cs in the Stern layer (relatively tightly bound to the basal oxygens), and the other to Cs in the Gouy diffuse layer. Between ∼-60 and ∼-10 degree C peaks for these two sites and a motionally-averaged peak are present. Cs-exchanged hectorite dehydrated at 500 degree C yields peaks for two different sites on the clay, interpreted to be highly coordinated site (probably 12), and a less coordinated site (possibly 9), both in the interlayer. Chapter II discusses 133Cs MAS NMR results for a number of other Cs-exchanged clays and the relationship of chemical and structural parameters to the 133Cs chemical shift. Increased rotational distortions of the basal oxygen sheet, total layer charge and tetrahedral Al3+ for Si4+ substitution correlate with increased deshielding of the 133Cs chemical shifts for both hydrated slurry and anhydrous samples. Correlations for the slurries are poorer because of the distances between the clay silicate and the CO in solution

  10. Sensitivity enhancement using paramagnetic relaxation in MAS solid-state NMR of perdeuterated proteins

    Linser, Rasmus; Chevelkov, Veniamin; Diehl, Anne; Reif, Bernd

    2007-12-01

    Previously, Ishii et al., could show that chelated paramagnetic ions can be employed to significantly decrease the recycle delay of a MAS solid-state NMR experiment [N.P. Wickramasinghe, M. Kotecha, A. Samoson, J. Past, Y. Ishii, Sensitivity enhancement in C-13 solid-state NMR of protein microcrystals by use of paramagnetic metal ions for optimizing H-1 T-1 relaxation, J. Magn. Reson. 184 (2007) 350-356]. Application of the method is limited to very robust samples, for which sample stability is not compromised by RF induced heating. In addition, probe integrity might be perturbed in standard MAS PRE experiments due to the use of very short duty cycles. We show that these deleterious effects can be avoided if perdeuterated proteins are employed that have been re-crystallized from D 2O:H 2O = 9:1 containing buffer solutions. The experiments are demonstrated using the SH3 domain of chicken α-spectrin as a model system. The labeling scheme allows to record proton detected 1H, 15N correlation spectra with very high resolution in the absence of heteronuclear dipolar decoupling. Cu-edta as a doping reagent yields a reduction of the recycle delay by up to a factor of 15. In particular, we find that the 1H T1 for the bulk H N magnetization is reduced from 4.4 s to 0.3 s if the Cu-edta concentration is increased from 0 mM to 250 mM. Possible perturbations like chemical shift changes or line broadening due to the paramagnetic chelate complex are minimal. No degradation of our samples was observed in the course of the experiments.

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

    Larsen, Flemming H; Byg, Inge; Damager, Iben; Diaz, Jerome; Engelsen, Søren B; Ulvskov, Peter

    2011-05-01

    Hydration of rhamnogalacturonan-I (RG-I) derived from potato cell wall was analyzed by (13)C single-pulse (SP) magic-angle-spinning (MAS) and (13)C cross-polarization (CP) MAS nuclear magnetic resonance (NMR) and supported by (2)H 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-galacturonic acid (Rha-GalA) backbone in RG-I. Potential food ingredient uses of RG-I by tailoring of its structure are discussed. PMID:21462966

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

    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

  13. Investigations of Li-containing SiCN(O) ceramics via 7Li MAS NMR.

    Gumann, Sina; Nestle, Nikolaus; Liebau-Kunzmann, Verena; Riedel, Ralf

    2007-04-01

    Lithium-containing silicon (oxy)carbonitride ceramics (SiCN(O):Li) were synthesized via precursor-to-ceramic-transformation of Li-containing (poly)silazanes. The precursors were obtained by lithiation of 2,4,6-trimethyl-2,4,6-trivinylcyclotrisilazane with n-butyllithium and by reaction of a commercial poly(organosilazane) VL20 with metallic lithium. The annealing treatment was carried out at temperatures between 200 and 1400 degrees C in argon (DeltaT=200 degrees C) and yielded Li-containing silicon (oxy)carbonitride. X-ray powder diffraction revealed that the resulting SiCN(O):Li ceramics were basically amorphous up to temperatures of 1000 degrees C and formed LiSi(2)N(3), graphite and silicon carbide as crystalline phases at higher temperatures. (7)Li MAS NMR spectroscopy was carried out to investigate the structure of the Li-containing phases and to study the reaction path of metallic Li with polysilazane. Based on the NMR spectra, there is almost no difference found in the chemical shift of the SiCN(O):Li ceramics obtained at different temperatures. Accordingly, Li is assigned to be mainly coordinated to N and O present as contaminant element. Relaxation time measurements showed that the most mobile Li(+) species seems to be present in the product obtained in the pyrolysis temperature range between 600 and 1000 degrees C. PMID:17418540

  14. Comparison of the 1H NMR analysis of solids by the CRAMPS and MAS-only techniques

    Dec, Steven F.; Bronnimann, Charles E.; Wind, Robert A.; Maciel, Gary E.

    1H NMR spectra are reported on eight representative solid samples, including pure powdered crystalline samples, synthetic organic polymers, a silica gel, HY zeolite, and a lignite. Spectra were obtained by the following three approaches: (1) single pulse on a static sample, (2) CRAMPS, and (3) single pulse with magic-angle spinning (MAS-only). The MAS-only results were obtained as a function of MAS speed. Although the MAS-only technique is capable of achieving a significant degree of line narrowing, even with modest MAS speeds, MAS-only spectra of the general quality of the apparently undistorted high-resolution 1H spectra obtained by the CRAMPS technique are not obtained at the highest MAS speeds examined (21 kHz for a polymethylmethacrylate sample), unless the 1H- 1H dipolar interactions in the sample are rather weak, as with silica gel or a zeolite. Thus, caution should be exercised in interpreting 1H MAS-only spectra, especially if CRAMPS results are not available as a calibration.

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

    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

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

    Zhang, Rongchun; Mroue, Kamal H.; Ramamoorthy, Ayyalusamy, E-mail: ramamoor@umich.edu [Biophysics and Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055 (United States)

    2015-10-14

    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), {sup 1}H MAS NMR spectra of rigid solids still suffer from poor resolution and severe peak overlap caused by the strong {sup 1}H–{sup 1}H homonuclear dipolar couplings and narrow {sup 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) {sup 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 {sup 1}H–{sup 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

  17. Structural nature of 7Li and 11B sites in the nonlinear optical material LiB3O5 using static NMR and MAS NMR

    The structural nature of the nonlinear optical properties of LiB3O5 is analyzed using single-crystal nuclear magnetic resonance (NMR) and magic angle spinning (MAS) NMR. The 3-coordinated trigonal [B(1) and B(2)] and 4-coordinated tetragonal [B(3)] sites are distinguished using the spectrum and the spin-lattice relaxation time in rotating frame T1ρ, which was obtained from the 11B MAS NMR. Moreover, the T1 and T1ρ values for 7Li and 11B are compared, and the activation energies were obtained. The T1ρ values of the boron nuclei in LiB3O5 show no significant changes. These results may be closely related to the largest second-order nonlinear optical coefficient. - Highlights: • The structural nature of the nonlinear optical properties of LiB3O5. • Single-crystal NMR and MAS NMR. • The 3-coordnated trigonal and 4-coordinated tetragonal. • The spin-lattice relaxation time in rotating frame T1ρ

  18. Rapid identification of osmolytes in tropical microalgae and cyanobacteria by (1)H HR-MAS NMR spectroscopy.

    Zea Obando, Claudia; Linossier, Isabelle; Kervarec, Nelly; Zubia, Mayalen; Turquet, Jean; Faÿ, Fabienne; Rehel, Karine

    2016-06-01

    In this study, we report the chemical characterization of 47 tropical microalgae and cyanobacteria by HR-MAS. The generated data confirm the interest of HR-MAS as a rapid screening technique with the major advantage of its easiness. The sample is used as powder of freeze-dried microalgae without any extraction process before acquisition. The spectral fingerprints of strains are then tested as variables for a chemotaxonomy study to discriminate cyanobacteria and dinoflagellates. The individual factor map generated by PCA analysis succeeds in separating the two groups, essentially thanks to the presence of specific carbohydrates. Furthermore, more resolved signals enable to identify many osmolytes. More precisely the characteristics δ of 2-O-alpha-D-glucosylglycerol (GG) are observed in all 21 h-MAS spectra of tropical cyanobacteria. After specific extraction, complementary analysis by 1D and 2D-NMR spectroscopies validates the identification of this osmolyte. PMID:27130130

  19. X-ray and MAS NMR characterization of the thermal transformation of Li(Na)-Y zeolite to lithium aluminosilicates

    The high temperature thermal transformation of Li-exchanged Na-Y zeolite has been investigated by X-ray diffraction and /sup 29/Si MAS NMR studies. At 7000C, the zeolite was transformed into an amorphous phase and upon further heating to 8000C, formation of lithium aluminosilicate with high-quartz structure, in addition to an amorphous phase, was noted. When heated above 9000C, the high-quartz structure was transformed into a β-spodumene related solid solution. X-ray and MAS NMR studies indicate the β-spodumene solid solution formed has the composition close to (Li/sub 0.23/Na/sub 0.06/)A iota /sub 0.29/Si/sub 0.71/O/sub 2/, which is in agreement with chemical analysis

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

    Urbanova, Martina; Brus, Jiri; Sedenkova, Ivana; Policianova, Olivia; Kobera, Libor

    In this contribution the ability of 19F MAS NMR spectroscopy to probe structural variability of poorly water-soluble drugs formulated as solid dispersions in polymer matrices is discussed. The application potentiality of the proposed approach is demonstrated on a moderately sized active pharmaceutical ingredient (API, Atorvastatin) exhibiting extensive polymorphism. In this respect, a range of model systems with the API incorporated in the matrix of polvinylpyrrolidone (PVP) was prepared. The extent of mixing of both components was determined by T1(1H) and T1ρ(1H) relaxation experiments, and it was found that the API forms nanosized domains. Subsequently it was found out that the polymer matrix induces two kinds of changes in 19F MAS NMR spectra. At first, this is a high-frequency shift reaching 2-3 ppm which is independent on molecular structure of the API and which results from the long-range polarization of the electron cloud around 19F nucleus induced by electrostatic fields of the polymer matrix. At second, this is broadening of the signals and formation of shoulders reflecting changes in molecular arrangement of the API. To avoid misleading in the interpretation of the recorded 19F MAS NMR spectra, because both the contributions act simultaneously, we applied chemometric approach based on multivariate analysis. It is demonstrated that factor analysis of the recorded spectra can separate both these spectral contributions, and the subtle structural differences in the molecular arrangement of the API in the nanosized domains can be traced. In this way 19F MAS NMR spectra of both pure APIs and APIs in solid dispersions can be directly compared. The proposed strategy thus provides a powerful tool for the analysis of new formulations of fluorinated pharmaceutical substances in polymer matrices.

  1. 1H MAS NMR characterization of hydrogen over silica-supported rhodium catalyst

    2001-01-01

    Hydrogen species in both SiO2 and Rh/SiO2 catalysts pretreated indifferent atmospheres (H2, O2, helium or air) at different temperatures (773 or 973 K) were investigated by means of 1H MAS NMR. In SiO2 and O2-pretreated catalysts, a series of downfield signals at ~7.0, 3.8-4.0, 2.0 and 1.5-1.0 were detected. The first two signals can be attributed to strongly adsorbed and physisorbed water and the others to terminal silanol (SiOH) and SiOH under the screening of oxygen vacancies in SiO2 lattice, respectively. Besides the above signals, both upfield signal at ~-110 and downfield signals at 3.0 and 0.0 were also detected in H2-pretreated catalyst, respectively. The upfield signal at ~-110 originated from the dissociative adsorption of H2 over rhodium and was found to consist of both the contributions of reversible and irreversible hydrogen. There also probably existed another dissociatively adsorbed hydrogen over rhodium, which was known to be b hydrogen and in a unique form of "delocalized hydrogen". It was presumed that the b hydrogen had an upfield shift of ca. -20- -50, though its 1H NMR signals, which, having been masked by the spinning sidebands of Si-OH, failed to be directly detected out. The downfield signal at 3.0 was assigned to spillover hydrogen weakly bound by the bridge oxygen of SiO2. Another downfield signal at 0.0 was assigned to hydrogen held in the oxygen vacancies of SiO2 (Si-H species), suffering from the screening of trapped electrons. Both the spillover hydrogen and the Si-H resulted from the migration of the reversible hydrogen and the b hydrogen from rhodium to SiO2 in the close vicinity. It was proved that the above migration of hydrogen was preferred to occur at higher temperature than at lower temperature.

  2. MAS-NMR study of lithium zinc silicate glasses and glass-ceramics with various ZnO content

    Lithium zinc silicate glasses of composition (mol%): 17.5Li2O-(72-x)SiO2-xZnO-5.1Na2O-1.3P2O5-4.1B2O3, 5.5≤x≤17.7, were prepared by conventional melt-quenched technique and converted to glass-ceramic by controlled crystallization process. 29Si and 31P MAS-NMR was used to characterize the structure of both glass and glass-ceramic samples. Despite the complex glass composition, Q2, Q3 and Q4 sites are identified from 29Si MAS-NMR, which relative intensities are found to vary with the ZnO content, indicating a network depolymerization by ZnO. Moreover, well separated Q3 and Q4 resonances for low ZnO content indicates the occurrence of phase separation. From 31P MAS-NMR, it is seen that phosphorus is mainly present in the form of ortho-(Q0) and pyro-phosphate (Q1) structural units and variation of ZnO content did not have much effect on these resonances, which provides an additional evidence for phase separation in the glass. On conversion to glass-ceramics, lithium disilicate (Li2Si2O5), lithium zinc ortho-silicate (Li3Zn0.5SiO4), tridymite (SiO2) and cristobalite (SiO2) were identified as major silicate crystalline phases. Using 29Si MAS-NMR, quantification of these silicate crystalline phases is carried out and correlated with the ZnO content in the glass-ceramics samples. In addition, 31P spectra unambiguously revealed the presence of crystalline Li3PO4 and (Na,Li)3PO4 in the glass-ceramics. - Graphical abstract: 29Si and 31P MAS-NMR analyses were carried out on multi-component Li2O-SiO2-ZnO-Na2O-P2O5-B2O3 glasses and glass-ceramics developed for sealing application. Structural data are reported, including phase separation process and quantification of amorphous and crystalline phases

  3. Temperature {sup 1}H, {sup 13}C, {sup 15}N NMR and CP/MAS {sup 15}N NMR spectra of benzotriazole derivatives - prototropic tautomerism; Widma temperaturowe {sup 1}H, {sup 13}C, {sup 15}N NMR oraz CP/MAS {sup 15}N NMR pochodnych benzotriazolu - tautomeria prototropowa

    Wiench, J.W.; Stefaniak, L. [Inst. Chemii Organicznej, Polska Akademia Nauk, Warsaw (Poland)

    1994-12-31

    The prototropic tautomerism in benzotriazole derivatives solutions has been investigated in different temperatures by means of {sup 1}H, {sup 13}C and {sup 15}N NMR and {sup 15}N CP/MAS NMR spectra. The ratio of different tautomeric forms and kinetics of proton exchange have been measured for the systems studied on the base of observed spectroscopic factors. 5 refs, 2 figs, 3 tabs.

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

    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.

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

    The plasticizing - antiplasticizing effect of water and glycerol contents on native corn starch samples is investigated by FT-Raman and 13C 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

  6. 1H HR-MAS NMR Spectroscopy and the Metabolite Determination of Typical Foods in Mediterranean Diet

    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.

  7. 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)

    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)

  8. 27Al Magic Angle Spinning–Nuclear Magnetic Resonance (MAS-NMR) Analyses Applied to Historical Mortars

    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

  9. CaCl2-Accelerated Hydration of Tricalcium Silicate: A STXM Study Combined with 29Si MAS NMR

    Qinfei Li; Yong Ge; Guoqing Geng; Sungchul Bae; Monteiro, Paulo J. M.

    2015-01-01

    The effect of calcium chloride (CaCl2) on tricalcium silicate (C3S) hydration was investigated by scanning transmission X-ray microscopy (STXM) with Near Edge X-ray Absorption Fine Structure (NEXAFS) spectra and 29Si MAS NMR. STXM is demonstrated to be a powerful tool for studying the chemical composition of a cement-based hydration system. The Ca L3,2-edge NEXAFS spectra obtained by examining C3S hydration in the presence of CaCl2 showed that this accelerator does not change the coordination...

  10. 2D 23Na-23Na DQ/MAS NMR spectroscopy: interface induced clustering and immobilization of sodium ions in nanostructured aluminosilicates

    Kobera, Libor; Urbanová, Martina; Brus, Jiří

    International Society of Magnetic Resonance, 2015. P 112. [Alpine Conference on Solid-State NMR /9./. 13.09.2015-17.09.2015, Chamonix Mont-Blanc] R&D Projects: GA ČR(CZ) GA13-24155S Institutional support: RVO:61389013 Keywords : MAS NMR * geopolymers * zeolites Subject RIV: JN - Civil Engineering

  11. 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

    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.

  12. Residual methyl protonation in perdeuterated proteins for multi-dimensional correlation experiments in MAS solid-state NMR spectroscopy

    Agarwal, Vipin; Reif, Bernd

    2008-09-01

    NMR studies involving perdeuterated proteins focus in general on exchangeable amide protons. However, non-exchangeable sites contain as well a small amount of protons as the employed precursors for protein biosynthesis are not completely proton depleted. The degree of methyl group protonation is in the order of 9% for CD 2H using >97% deuterium enriched glucose. We show in this manuscript that this small amount of residual protonation is sufficient to perform 2D and 3D MAS solid-state NMR experiments. In particular, we suggest a HCCH-TOBSY type experiment which we successfully employ to assign the methyl resonances in aliphatic side chains in a perdeuterated sample of the SH3 domain of chicken α-spectrin.

  13. Sealed rotors for in situ high temperature high pressure MAS NMR.

    Hu, Jian Zhi; Hu, Mary Y; Zhao, Zhenchao; Xu, Suochang; Vjunov, Aleksei; Shi, Hui; Camaioni, Donald M; Peden, Charles H F; Lercher, Johannes A

    2015-09-11

    Here we present the design of reusable and perfectly sealed all-zirconia MAS rotors. The rotors are used to study AlPO4-5 molecular sieve crystallization under hydrothermal conditions, high temperature high pressure cyclohexanol dehydration reaction, and low temperature metabolomics of intact biological tissue. PMID:26171928

  14. Site-resolved (2)H relaxation experiments in solid materials by global line-shape analysis of MAS NMR spectra.

    Lindh, E L; Stilbs, P; Furó, I

    2016-07-01

    We investigate a way one can achieve good spectral resolution in (2)H MAS NMR experiments. The goal is to be able to distinguish between and study sites in various deuterated materials with small chemical shift dispersion. We show that the (2)H MAS NMR spectra recorded during a spin-relaxation experiment are amenable to spectral decomposition because of the different evolution of spectral components during the relaxation delay. We verify that the results are robust by global least-square fitting of the spectral series both under the assumption of specific line shapes and without such assumptions (COmponent-REsolved spectroscopy, CORE). In addition, we investigate the reliability of the developed protocol by analyzing spectra simulated with different combinations of spectral parameters. The performance is demonstrated in a model material of deuterated poly(methacrylic acid) that contains two (2)H spin populations with similar chemical shifts but different quadrupole splittings. In (2)H-exchanged cellulose containing two (2)H spin populations with very similar chemical shifts and quadrupole splittings, the method provides new site-selective information about the molecular dynamics. PMID:27152833

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

    Sardessai, S.; Wahidullah, S.

    Humic acids from sediments of different depositional environments have been studied by solid-state sup(13)C NMR and the results compared with the traditional wet chemical analysis. Results obtained are well in agreement with the previous literature...

  16. Polydisperse methyl β-cyclodextrin–epichlorohydrin polymers: variable contact time 13C CP-MAS solid-state NMR characterization

    Isabelle Mallard

    2015-12-01

    Full Text Available The polymerization of partially methylated β-cyclodextrin (CRYSMEB with epichlorohydrin was carried out in the presence of a known amount of toluene as imprinting agent. Three different preparations (D1, D2 and D3 of imprinted polymers were obtained and characterized by solid-state 13C NMR spectroscopy under cross-polarization magic angle spinning (CP-MAS conditions. The polymers were prepared by using the same synthetic conditions but with different molar ratios of imprinting agent/monomer, leading to morphologically equivalent materials but with different absorption properties. The main purpose of the work was to find a suitable spectroscopic descriptor accounting for the different imprinting process in three homogeneous polymeric networks. The polymers were characterized by studying the kinetics of the cross-polarization process. This approach is based on variable contact time CP-MAS spectra, referred to as VCP-MAS. The analysis of the VCP-MAS spectra provided two relaxation parameters: TCH (the CP time constant and T1ρ (the proton spin-lattice relaxation time in the rotating frame. The results and the analysis presented in the paper pointed out that TCH is sensitive to the imprinting process, showing variations related to the toluene/cyclodextrin molar ratio used for the preparation of the materials. Conversely, the observed values of T1ρ did not show dramatic variations with the imprinting protocol, but rather confirmed that the three polymers are morphologically similar. Thus the combined use of TCH and T1ρ can be helpful for the characterization and fine tuning of imprinted polymeric matrices.

  17. Polydisperse methyl β-cyclodextrin-epichlorohydrin polymers: variable contact time (13)C CP-MAS solid-state NMR characterization.

    Mallard, Isabelle; Baudelet, Davy; Castiglione, Franca; Ferro, Monica; Panzeri, Walter; Ragg, Enzio; Mele, Andrea

    2015-01-01

    The polymerization of partially methylated β-cyclodextrin (CRYSMEB) with epichlorohydrin was carried out in the presence of a known amount of toluene as imprinting agent. Three different preparations (D1, D2 and D3) of imprinted polymers were obtained and characterized by solid-state (13)C NMR spectroscopy under cross-polarization magic angle spinning (CP-MAS) conditions. The polymers were prepared by using the same synthetic conditions but with different molar ratios of imprinting agent/monomer, leading to morphologically equivalent materials but with different absorption properties. The main purpose of the work was to find a suitable spectroscopic descriptor accounting for the different imprinting process in three homogeneous polymeric networks. The polymers were characterized by studying the kinetics of the cross-polarization process. This approach is based on variable contact time CP-MAS spectra, referred to as VCP-MAS. The analysis of the VCP-MAS spectra provided two relaxation parameters: T CH (the CP time constant) and T 1ρ (the proton spin-lattice relaxation time in the rotating frame). The results and the analysis presented in the paper pointed out that T CH is sensitive to the imprinting process, showing variations related to the toluene/cyclodextrin molar ratio used for the preparation of the materials. Conversely, the observed values of T 1ρ did not show dramatic variations with the imprinting protocol, but rather confirmed that the three polymers are morphologically similar. Thus the combined use of T CH and T 1ρ can be helpful for the characterization and fine tuning of imprinted polymeric matrices. PMID:26877800

  18. Polydisperse methyl β-cyclodextrin–epichlorohydrin polymers: variable contact time 13C CP-MAS solid-state NMR characterization

    Mallard, Isabelle; Baudelet, Davy; Castiglione, Franca; Ferro, Monica; Panzeri, Walter; Ragg, Enzio

    2015-01-01

    Summary The polymerization of partially methylated β-cyclodextrin (CRYSMEB) with epichlorohydrin was carried out in the presence of a known amount of toluene as imprinting agent. Three different preparations (D1, D2 and D3) of imprinted polymers were obtained and characterized by solid-state 13C NMR spectroscopy under cross-polarization magic angle spinning (CP-MAS) conditions. The polymers were prepared by using the same synthetic conditions but with different molar ratios of imprinting agent/monomer, leading to morphologically equivalent materials but with different absorption properties. The main purpose of the work was to find a suitable spectroscopic descriptor accounting for the different imprinting process in three homogeneous polymeric networks. The polymers were characterized by studying the kinetics of the cross-polarization process. This approach is based on variable contact time CP-MAS spectra, referred to as VCP-MAS. The analysis of the VCP-MAS spectra provided two relaxation parameters: T CH (the CP time constant) and T 1ρ (the proton spin-lattice relaxation time in the rotating frame). The results and the analysis presented in the paper pointed out that T CH is sensitive to the imprinting process, showing variations related to the toluene/cyclodextrin molar ratio used for the preparation of the materials. Conversely, the observed values of T 1ρ did not show dramatic variations with the imprinting protocol, but rather confirmed that the three polymers are morphologically similar. Thus the combined use of T CH and T 1ρ can be helpful for the characterization and fine tuning of imprinted polymeric matrices. PMID:26877800

  19. Combined high-field 13C CP MAS NMR and low-field NMR relaxation measurements on post mortem porcine muscles.

    Bertram, Hanne Christine; Jakobsen, Hans Jørgen; Andersen, Henrik Jørgen

    2004-05-19

    Changes in postmortem muscle characteristics are investigated in muscles from eight pigs exposed to different combinations of preslaughter stress (exercise on treadmill) and stunning method (CO(2) vs electrical stunning). Solid-state (13)C cross-polarization (CP) magic-angle spinning (MAS) NMR experiments are carried out on a total of 16 rapidly frozen M. longissimus muscle biopsies taken in vivo the day before slaughter and at 45 min postmortem. Simultaneously, low-field NMR T(2) relaxation time measurements are carried out on samples from M. longissimus. Glycogen and lactate are estimated from the (13)C CP MAS spectra, and correlations of r = 0.89 and r = 0.70, respectively, to subsequent biochemical determinations using partial least squares regression (PLSR) are established. Moreover, PLSR reveals that, besides the 72 ppm signal (carbons in glycogen), a signal around 38 ppm, which increases concomitantly with lactate, is also significantly correlated to changes in glycogen/lactate. With the assumption that the 38 ppm signal reflects CH(2) in phosphocreatine/creatine, altered mobility of creatine as a result of dephosphorylation is indicated. Finally, PLSR on the 45 min (13)C CP MAS spectra also reveals correlation (r = 0.54) to the slowest relaxing T(2) population (50 min postmortem), known to reflect extra-myofibrillar water. Subsequently, evaluation of the loading plot in the PLSR analysis reveals that the correlation exclusively is associated to the 52 ppm resonance intensity. With the assumption that this resonance reflects methyl groups in choline/phosphatidyl choline, the intensity changes in the 52 ppm resonance imply alterations in membrane properties. Accordingly, the data indicate a relationship between membrane properties and the amount of water being expelled from muscle cells postmortem, which supports the hypothesis that disruption of membranes is implicated in the postmortem mobilization of muscle water. PMID:15137869

  20. Application of (119)Sn CPMG MAS NMR for Fast Characterization of Sn Sites in Zeolites with Natural (119)Sn Isotope Abundance.

    Kolyagin, Yury G; Yakimov, Alexander V; Tolborg, Søren; Vennestrøm, Peter N R; Ivanova, Irina I

    2016-04-01

    (119)Sn CPMG MAS NMR is demonstrated to be a fast and efficient method for characterization of Sn-sites in Sn-containing zeolites. Tuning of the CPMG echo-train sequence decreases the experimental time by a factor of 5-40 in the case of as-synthesized and hydrated Sn-BEA samples and by 3 orders of magnitude in the case of dehydrated Sn-BEA samples as compared to conventional methods. In the latter case, the reconstruction of the quantitative spectrum without the loss of sensitivity is shown to be possible. The method proposed allows obtaining (119)Sn MAS NMR spectra with improved resolution for Sn-BEA zeolites with natural (119)Sn isotope abundance using conventional MAS NMR equipment. PMID:26978430

  1. Investigation on Acute Biochemical Effects of Ce(NO3)3 on Liver and Kidney Tissues by MAS 1H NMR Spectroscopic-Based Metabonomic Approach

    2006-01-01

    High resolution magic angle spinning (MAS)-1 H nuclear magnetic resonance (NMR) spectroscopic-based metabonomic approach was applied to the investigation on the acute biochemical effects of Ce(NO3)3. Male Wistar rats were liver and kidney tissues were analyzed using principal component analysis to extract toxicity information. The biochemical effects of Ce(NO3)3 were characterized by the increase of triglycerides and lactate and the decrease of glycogen in rat liver tissue, together with an elevation of the triglyceride level and a depletion of glycerophosphocholine and betaine in kidney tissues. The target lesions of Ce(NO3)3 on liver and kidney were found by MAS NMR-based metabonomic method. This study demonstrates that the combination of MAS 1H NMR and pattern recognition analysis can be an effective method for studies of biochemical effects of rare earths.

  2. SCAM-STMAS: satellite-transition MAS NMR of quadrupolar nuclei with self-compensation for magic-angle misset

    Ashbrook, Sharon E.; Wimperis, Stephen

    2003-06-01

    Several methods are available for the acquisition of high-resolution solid-state NMR spectra of quadrupolar nuclei with half-integer spin quantum number. Satellite-transition MAS (STMAS) offers an approach that employs only conventional MAS hardware and can yield substantial signal enhancements over the widely used multiple-quantum MAS (MQMAS) experiment. However, the presence of the first-order quadrupolar interaction in the satellite transitions imposes the requirement of a high degree of accuracy in the setting of the magic angle on the NMR probehead. The first-order quadrupolar interaction is only fully removed if the sample spinning angle, χ, equals cos-1(1/ 3) exactly and rotor synchronization is performed. The required level of accuracy is difficult to achieve experimentally, particularly when the quadrupolar interaction is large. If the magic angle is not set correctly, the first-order splitting is reintroduced and the spectral resolution is severely compromised. Recently, we have demonstrated a novel STMAS method (SCAM-STMAS) that is self-compensated for angle missets of up to ±1° via coherence transfer between the two different satellite transitions ST +( mI=+3/2↔+1/2) and ST -( mI=-1/2↔-3/2) midway through the t1 period. In this work we describe in more detail the implementation of SCAM-STMAS and demonstrate its wider utility through 23Na ( I=3/2), 87Rb ( I=3/2), 27Al ( I=5/2), and 59Co ( I=7/2) NMR. We discuss linewidths in SCAM-STMAS and the limits over which angle-misset compensation is achieved and we demonstrate that SCAM-STMAS is more tolerant of temporary spinning rate fluctuations than STMAS, resulting in less " t1 noise" in the two-dimensional spectrum. In addition, alternative correlation experiments, for example involving the use of double-quantum coherences, that similarly display self-compensation for angle misset are investigated. The use of SCAM-STMAS is also considered in systems where other high-order interactions, such as third

  3. 6Li MAS NMR Study of Lithium Insertion into Hydrothermally Prepared Li-Ti-O Spinel

    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

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

    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 alit...... belite, and silica fume are determined. It is demonstrated that 27Al MAS NMR spectra of hydrated Portland cements can give quantitative information about the formation of ettringite and the conversion of this phase to monosulphate during hydration....

  5. Determination of nuclear distances and chemical-shift anisotropy from 1H MAS NMR sideband patterns of surface OH groups

    Fenzke, Dieter; Hunger, Michael; Pfeifer, Harry

    A procedure is described which allows a separate determination of the proton-aluminum distance and of the chemical-shift anisotropy for the bridging OH groups of crystalline molecular sieves from their 'H MAS NMR sideband patterns. For the bridging OH groups which point into the 6-rings of the framework (line "c"), the 1H- 27Al distance could be determined to be 0.237 ± 0.004 and 0.234 ± 0.004 nm for molecular sieves of type H-Y and SAPO-5, respectively. In contrast, for the bridging OH groups of the 12-rings (line "b"), the corresponding distances are equal and distinctly larger, 0.248 ± 0.004 nm. Within the limits of error, the values of the chemical-shift anisotropy are equal (about 19 ± 2 ppm) except for line b of SAPO-5, which exhibits a much smaller value of 14.5 ± 2 ppm.

  6. 13C MAS NMR studies of the effects of hydration on the cell walls of potatoes and Chinese water chestnuts.

    Tang, H; Belton, P S; Ng, A; Ryden, P

    1999-02-01

    13C NMR with magic angle spinning (MAS) has been employed to investigate the cell walls of potatoes and Chinese water chestnuts over a range of hydration levels. Both single-pulse excitation (SPEMAS) and cross-polarization (CPMAS) experiments were carried out. Hydration led to a substantial increase in signal intensities of galactan and galacturonan in the SPEMAS spectra and a decrease in line width, implying mobilization in the backbone and side chains of pectin. In CPMAS spectra of both samples, noncellulose components showed signal loss as hydration increased. However, the signals of some galacturonan in the 3(1) helix configuration remained in the spectra even when the water content was as high as 110%. Cellulose was unaffected. It is concluded that the pectic polysaccharides experience a distribution of molecular conformations and mobility, whereas cellulose remained as typical rigid solid. PMID:10563925

  7. Assignment of amide proton signals by combined evaluation of HN, NN and HNCA MAS-NMR correlation spectra

    Rossum, Barth-Jan van; Castellani, Federica [Forschungsinstitut fuer Molekulare Pharmakologie (FMP) (Germany); Pauli, Jutta [BAM (Germany); Rehbein, Kristina [Forschungsinstitut fuer Molekulare Pharmakologie (FMP) (Germany); Hollander, J.; Groot, Huub J.M. de [BAM (Germany); Oschkinat, Hartmut [Forschungsinstitut fuer Molekulare Pharmakologie (FMP) (Germany)], E-mail: Oschkinat@fmp-berlin.de

    2003-03-15

    In this paper, we present a strategy for the {sup 1}H{sup N} resonance assignment in solid-state magic-angle spinning (MAS) NMR, using the {alpha}-spectrin SH3 domain as an example. A novel 3D triple resonance experiment is presented that yields intraresidue H{sup N}-N-C{sup {alpha}} correlations, which was essential for the proton assignment. For the observable residues, 52 out of the 54 amide proton resonances were assigned from 2D ({sup 1}H-{sup 15}N) and 3D ({sup 1}H-{sup 15}N-{sup 13}C) heteronuclear correlation spectra. It is demonstrated that proton-driven spin diffusion (PDSD) experiments recorded with long mixing times (4 s) are helpful for confirming the assignment of the protein backbone {sup 15}N resonances and as an aid in the amide proton assignment.

  8. Sensitivity Gains, Linearity, and Spectral Reproducibility in Nonuniformly Sampled Multidimensional MAS NMR Spectra of High Dynamic Range.

    Suiter, Christopher L.; Paramasivam, Sivakumar; Hou, Guangjin; Sun, Shangjin; Rice, David M.; Hoch, Jeffrey C.; Rovnyak, David S.; Polenova, Tatyana E.

    2014-04-22

    Recently, we have demonstrated that considerable inherent sensitivity gains are attained in MAS NMR spectra acquired by nonuniform sampling (NUS) and introduced maximum entropy interpolation (MINT) processing that assures the linearity of transformation between the time and frequency domains. In this report, we examine the utility of the NUS/MINT approach in multidimensional datasets possessing high dynamic range, such as homonuclear 13C–13C correlation spectra. We demonstrate on model compounds and on 1–73-(U-13C,15N)/74–108-(U-15N) E. coli thioredoxin reassembly, that with appropriately constructed 50 % NUS schedules inherent sensitivity gains of 1.7–2.1-fold are readily reached in such datasets. We show that both linearity and line width are retained under these experimental conditions throughout the entire dynamic range of the signals. Furthermore, we demonstrate that the reproducibility of the peak intensities is excellent in the NUS/MINT approach when experiments are repeated multiple times and identical experimental and processing conditions are employed. Finally, we discuss the principles for design and implementation of random exponentially biased NUS sampling schedules for homonuclear 13C–13C MAS correlation experiments that yield high quality artifact-free datasets.

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

    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.

  10. Coal structure at reactive sites by sup 1 H- sup 13 C- sup 19 F double cross polarization (DCP)/MAS sup 13 C NMR spectroscopy

    Hagaman, E.W.; Woody, M.C. (Oak Ridge National Lab., TN (USA))

    1989-01-01

    The solid state NMR technique, {sup 1}H-{sup 13}C-{sup 31}P double cross polarization (DCP)/MAS {sup 13}C-NMR spectroscopy, uses the direct dipolar interaction between {sup 13}C-{sup 31}P spin pairs in organophosphorus substances to identify the subset of carbons within a spherical volume element of 0.4 nm radius centered on the {sup 31}P atom. In combination with chemical manipulation of coals designed to introduce phosphorus containing functionality into the organic matrix, the NMR experiment becomes a method to examine selectively the carbon bonding network at the reactive sites in the coal. This approach generates a statistical structure description of the coal at the reaction centers in contrast to bulk carbon characterization using conventional {sup 1}H-{sup 13}C CP/MAS {sup 13}C NMR spectroscopy. 3 refs.

  11. Application of High-Resolution 1H MAS NMR Spectroscopy to the Analysis of Intact Bones from Mice Exposed to Gamma Radiation

    Zhang, QiBin; Hu, Jian Zhi; Rommereim, Donald N.; Murphy, Mark K; Phipps, Richard P.; HUSO, DAVID L.; Dicello, John F

    2009-01-01

    Herein we demonstrate that high-resolution magic angle spinning (MAS) 1H NMR can be used to profile the pathology of bone marrow rapidly and with minimal sample preparation. The spectral resolution obtained allows several metabolites to be analyzed quantitatively. The level of NMR-detectable metabolites in the epiphysis + metaphysis sections of mouse femur were significantly higher than that observed in the diaphysis of the same femur. The major metabolite damage to bone marrow resulting from...

  12. Structural investigations of PuIII phosphate by X-ray diffraction, MAS-NMR and XANES spectroscopy

    PuPO4 was prepared by a solid state reaction method and its crystal structure at room temperature was solved by powder X-ray diffraction combined with Rietveld refinement. High resolution XANES measurements confirm the +III valence state of plutonium, in agreement with valence bond derivation. The presence of the americium (as β− decay product of plutonium) in the +III oxidation state was determined based on XANES spectroscopy. High resolution solid state 31P NMR agrees with the XANES results and the presence of a solid-solution. - Graphical abstract: A full structural analysis of PuPO4 based on Rietveld analysis of room temperature X-ray diffraction data, XANES and MAS NMR measurements was performed. - Highlights: • The crystal structure of PuPO4 monazite is solved. • In PuPO4 plutonium is strictly trivalent. • The presence of a minute amount of AmIII is highlighted. • We propose PuPO4 as a potential reference material for spectroscopic and microscopic studies

  13. Structural investigations of Pu{sup III} phosphate by X-ray diffraction, MAS-NMR and XANES spectroscopy

    Popa, Karin [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe (Germany); Raison, Philippe E., E-mail: philippe.raison@ec.europa.eu [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe (Germany); Martel, Laura [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe (Germany); Martin, Philippe M. [CEA, DEN, DEC/SESC, F-13108 Saint Paul Lez Durance Cedex (France); Prieur, Damien [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe (Germany); Solari, Pier L. [Synchrotron SOLEIL, 91190 Saint-Aubin (France); Bouëxière, Daniel; Konings, Rudy J.M.; Somers, Joseph [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe (Germany)

    2015-10-15

    PuPO{sub 4} was prepared by a solid state reaction method and its crystal structure at room temperature was solved by powder X-ray diffraction combined with Rietveld refinement. High resolution XANES measurements confirm the +III valence state of plutonium, in agreement with valence bond derivation. The presence of the americium (as β{sup −} decay product of plutonium) in the +III oxidation state was determined based on XANES spectroscopy. High resolution solid state {sup 31}P NMR agrees with the XANES results and the presence of a solid-solution. - Graphical abstract: A full structural analysis of PuPO{sub 4} based on Rietveld analysis of room temperature X-ray diffraction data, XANES and MAS NMR measurements was performed. - Highlights: • The crystal structure of PuPO{sub 4} monazite is solved. • In PuPO{sub 4} plutonium is strictly trivalent. • The presence of a minute amount of Am{sup III} is highlighted. • We propose PuPO{sub 4} as a potential reference material for spectroscopic and microscopic studies.

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

    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

  15. Proton-detected scalar coupling based assignment strategies in MAS solid-state NMR spectroscopy applied to perdeuterated proteins

    Linser, Rasmus; Fink, Uwe; Reif, Bernd

    2008-07-01

    Assignment of proteins in MAS (magic angle spinning) solid-state NMR relies so far on correlations among heteronuclei. This strategy is based on well dispersed resonances in the 15N dimension. In many complex cases like membrane proteins or amyloid fibrils, an additional frequency dimension is desirable in order to spread the amide resonances. We show here that proton detected HNCO, HNCA, and HNCACB type experiments can successfully be implemented in the solid-state. Coherences are sufficiently long lived to allow pulse schemes of a duration greater than 70 ms before incrementation of the first indirect dimension. The achieved resolution is comparable to the resolution obtained in solution-state NMR experiments. We demonstrate the experiments using a triply labeled sample of the SH3 domain of chicken α-spectrin, which was re-crystallized in H 2O/D 2O using a ratio of 1/9. We employ paramagnetic relaxation enhancement (PRE) using EDTA chelated Cu II to enable rapid data acquisition.

  16. Application of 119Sn CPMG MAS NMR for Fast Characterization of Sn Sites in Zeolites with Natural 119Sn Isotope Abundance

    G. Kolyagin, Yury; V. Yakimo, Alexander; Tolborg, Søren;

    2016-01-01

    119Sn CPMG MAS NMR is demonstrated to be a fast and efficient method for characterization of Sn-sites in Sn-containing zeolites. Tuning of the CPMG echo-train sequence decreases the experimental time by a factor of 5–40 in the case of as-synthesized and hydrated Sn-BEA samples and by 3 orders of...

  17. 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

    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, e...

  18. Dynamic effects in MAS and MQMAS NMR spectra of half-integer quadrupolar nuclei: calculations and an application to the double perovskite cryolite.

    Kotecha, Mrignayani; Chaudhuri, Santanu; Grey, Clare P; Frydman, Lucio

    2005-11-30

    Dynamic processes such as chemical exchange or rotations between inequivalent orientations can affect the magic-angle spinning (MAS) and the multiple-quantum (MQ) MAS NMR spectra of half-integer quadrupolar nuclei. The present paper discusses such dynamic multisite MAS and MQMAS effects and applies them to study the dynamic processes that occur in the double perovskite cryolite, Na3AlF6. Dynamic line shape simulations invoking a second-order broadening of the central transition and relying on the semiclassical Bloch-McConnell formalism for chemical exchange were performed for a variety of exchange models possessing different symmetries. Fitting experimental variable-temperature cryolite 23Na NMR data with this formalism revealed that the two inequivalent sodium sites in this mineral undergo an exchange characterized by a broad distribution of rates. To further assess this dynamic process a variety of 27Al and 19F MAS NMR studies were also undertaken; quantitative 27Al-19F dipolar coupling measurements then revealed a dynamic motion of the AlF6 octahedra that were qualitatively consistent with predictions stemming from molecular dynamic simulations on this double perovskite. PMID:16305261

  19. CP-MAS 207Pb with 19F decoupling NMR spectroscopy: medium range investigation in fluoride materials.

    Bureau, B; Silly, G; Buzaré, J Y

    1999-11-01

    The isotropic chemical shift of 207Pb is used to perform structural investigations of crystalline fluoride compounds (PbF2, Pb2ZnF6, PbGaF5, Pb3Ga2F12 and Pb9Ga2F24) and transition metal fluoride glasses (TMFG) of the PZG family (PbF2-ZnF2-GaF3). Using 207Pb Cross Polarisation Magic Angle Spinning (CP-MAS) NMR with 19F decoupling, it is shown that the isotropic chemical shift of 207Pb varies on a large scale (1000 ppm) and that the main changes of its value are not due to the nearest neighbour fluorines but may be related to the number of next nearest neighbour (nnn) Pb2+ ions. In this way, it is demonstrated that 207Pb chemical shift is an interesting probe to investigate medium range order in either crystalline or glassy fluoride systems. The 207Pb delta(iso) parameter has been linearly correlated to the number of nnn Pb2+ ions. PMID:10670899

  20. N Photo-CIDNP MAS NMR To Reveal Functional Heterogeneity in Electron Donor of Different Plant Organisms.

    Janssen, Geertje J; Roy, Esha; Matysik, Jörg; Alia, A

    2012-02-01

    In plants and cyanobacteria, two light-driven electron pumps, photosystems I and II (PSI, PSII), facilitate electron transfer from water to carbon dioxide with quantum efficiency close to unity. While similar in structure and function, the reaction centers of PSI and PSII operate at widely different potentials with PSI being the strongest reducing agent known in living nature. Photochemically induced dynamic nuclear polarization (photo-CIDNP) in magic-angle spinning (MAS) nuclear magnetic resonance (NMR) measurements provides direct excess to the heart of large photosynthetic complexes (A. Diller, Alia, E. Roy, P. Gast, H.J. van Gorkom, J. Zaanen, H.J.M. de Groot, C. Glaubitz, J. Matysik, Photosynth. Res. 84, 303-308, 2005; Alia, E. Roy, P. Gast, H.J. van Gorkom, H.J.M. de Groot, G. Jeschke, J. Matysik, J. Am. Chem. Soc. 126, 12819-12826, 2004). By combining the dramatic signal increase obtained from the solid-state photo-CIDNP effect with (15)N isotope labeling of PSI, we were able to map the electron spin density in the active cofactors of PSI and study primary charge separation at atomic level. We compare data obtained from two different PSI proteins, one from spinach (Spinacia oleracea) and other from the aquatic plant duckweed (Spirodella oligorrhiza). Results demonstrate a large flexibility of the PSI in terms of its electronic architecture while their electronic ground states are strictly conserved. PMID:22303078

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

    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.

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

    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 ∼0.44 Å, a tilt angle of 24° ± 1°, and an azimuthal angle of 55° ± 6°. 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

  3. Identification of Li-Ion Battery SEI Compounds through (7)Li and (13)C Solid-State MAS NMR Spectroscopy and MALDI-TOF Mass Spectrometry.

    Huff, Laura A; Tavassol, Hadi; Esbenshade, Jennifer L; Xing, Wenting; Chiang, Yet-Ming; Gewirth, Andrew A

    2016-01-13

    Solid-state (7)Li and (13)C MAS NMR spectra of cycled graphitic Li-ion anodes demonstrate SEI compound formation upon lithiation that is followed by changes in the SEI upon delithiation. Solid-state (13)C DPMAS NMR shows changes in peaks associated with organic solvent compounds (ethylene carbonate and dimethyl carbonate, EC/DMC) upon electrochemical cycling due to the formation of and subsequent changes in the SEI compounds. Solid-state (13)C NMR spin-lattice (T1) relaxation time measurements of lithiated Li-ion anodes and reference poly(ethylene oxide) (PEO) powders, along with MALDI-TOF mass spectrometry results, indicate that large-molecular-weight polymers are formed in the SEI layers of the discharged anodes. MALDI-TOF MS and NMR spectroscopy results additionally indicate that delithiated anodes exhibit a larger number of SEI products than is found in lithiated anodes. PMID:26653886

  4. 13C chemical shift anisotropies for carbonate ions in cement minerals and the use of 13C, 27Al and 29Si MAS NMR in studies of Portland cement including limestone additions

    13C isotropic chemical shifts and chemical shift anisotropy parameters have been determined for a number of inorganic carbonates relevant in cement chemistry from slow-speed 13C MAS or 13C(1H) CP/MAS NMR spectra (9.4 T or 14.1 T) for 13C in natural abundance. The variation in the 13C chemical shift parameters is relatively small, raising some doubts that different carbonate species in Portland cement-based materials may not be sufficiently resolved in 13C MAS NMR spectra. However, it is shown that by combining 13C MAS and 13C(1H) CP/MAS NMR carbonate anions in anhydrous and hydrated phases can be distinguished, thereby providing valuable information about the reactivity of limestone in cement blends. This is illustrated for three cement pastes prepared from an ordinary Portland cement, including 0, 16, and 25 wt.% limestone, and following the hydration for up to one year. For these blends 29Si MAS NMR reveals that the limestone filler accelerates the hydration for alite and also results in a smaller fraction of tetrahedrally coordinated Al incorporated in the C-S-H phase. The latter result is more clearly observed in 27Al MAS NMR spectra of the cement–limestone blends and suggests that dissolved aluminate species in the cement–limestone blends readily react with carbonate ions from the limestone filler, forming calcium monocarboaluminate hydrate. -- Highlights: •13C chemical shift anisotropies for inorganic carbonates from 13C MAS NMR. •Narrow 13C NMR chemical shift range (163–171 ppm) for inorganic carbonates. •Anhydrous and hydrated carbonate species by 13C MAS and 13C(1H) CP/MAS NMR. •Limestone accelerates the hydration for alite in Portland – limestone cements. •Limestone reduces the amount of aluminium incorporated in the C-S-H phase

  5. Nanoscopic yttrium oxide fluorides: non-aqueous fluorolytic sol-gel synthesis and structural insights by 19F and 89Y MAS NMR.

    Scholz, G; Dreger, M; Bertram, R; Kemnitz, E

    2015-08-14

    Nanoscopic yttrium acetate fluorides Y(CH(3)COO)(3-z)F(z) and yttrium oxide fluorides YO(3-z)/(2)F(z )were prepared with tunable Y/F molar ratios via the fluorolytic sol-gel route. All samples were characterized by X-ray diffraction, elemental analysis and thermal analysis. In addition, local structures of all samples were studied by (19)F MAS, (19)F-(89)Y CP MAS and (1)H-(89)Y CP MAS NMR spectroscopy and the respective chemical shifts are given. For both classes of compounds, only the fluorination using one equivalent of F (z = 1) leads to defined, well crystalline matrices: yttrium acetate fluoride Y(CH(3)COO)(2)F and r-YOF. PMID:26133504

  6. 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

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

    2012-07-01

    The location of extraframework cations in Sr2+ and Ba2+ ion-exchanged SAPO-34 was estimated by means of 1H and 23Na 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 CO2 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.

  7. Hydrogen-bond interactions in organically-modified polysiloxane networks studied by 1D and 2D CRAMPS and double-quantum 1H MAS NMR

    Brus, Jiří; Dybal, Jiří

    2002-01-01

    Roč. 35, č. 27 (2002), s. 10038-10047. ISSN 0024-9297 R&D Projects: GA ČR GA203/98/P290; GA AV ČR KSK4050111 Institutional research plan: CEZ:AV0Z4050913 Keywords : Hydrogen bonding * polysiloxane * 1H MAS NMR Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.751, year: 2002

  8. 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

    The location of extraframework cations in Sr2+ and Ba2+ ion-exchanged SAPO-34 was estimated by means of 1H and 23Na 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 CO2 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 CO2 adsorption performance. Highlights: ► Location of extraframework Sr2+ or Ba2+ cations was estimated by means of 1H and 23Na MAS NMR. ► Level of Sr2+ or Ba2+ ion exchange was limited by the presence of protons and sodium cations. ► Presence of ammonium cations in the supercages facilitated the exchange. ► Sr2+ and Ba2+ ion exchanged SAPOs are outstanding CO2 adsorbents.

  9. Ease of delignification assesment of wood from different Eucalyptus species by pyrolysis (TMAH)-GC/MS and CP/MAS 13C-NMR spectrometry

    González-Vila, Francisco Javier; Almendros Martín, Gonzalo; Río Andrade, José Carlos del; Martín Martínez, Francisco; Gutiérrez Suárez, Ana; Romero Sánchez, Juan

    1999-01-01

    Flash-pyrolysis in the presence of tetramethylammonium hydroxide (TMAH) of woods from different species of Eucalyptus yields series of guaiacyl-type (G) and syringyl-type (S) units in slightly but characteristically different relative proportions. Such differences have been used to suggest a fine and appropriate index of the ease of delignification of the different Eucalyptus species when pulped by the Kraft process. The pyrolytic data were in agreement with those obtained from CP/MAS 13C-NMR...

  10. Optimum levels of exchangeable protons in perdeuterated proteins for proton detection in MAS solid-state NMR spectroscopy

    Akbey, Umit; Lange, Sascha; Trent Franks, W.; Linser, Rasmus; Rehbein, Kristina; Diehl, Anne; Rossum, Barth-Jan van; Reif, Bernd; Oschkinat, Hartmut, E-mail: oschkinat@fmp-berlin.d [Leibniz-Forschungsinstitut fuer Molekulare Pharmakologie (FMP) (Germany)

    2010-01-15

    We present a systematic study of the effect of the level of exchangeable protons on the observed amide proton linewidth obtained in perdeuterated proteins. Decreasing the amount of D{sub 2}O employed in the crystallization buffer from 90 to 0%, we observe a fourfold increase in linewidth for both {sup 1}H and {sup 15}N resonances. At the same time, we find a gradual increase in the signal-to-noise ratio (SNR) for {sup 1}H-{sup 15}N correlations in dipolar coupling based experiments for H{sub 2}O concentrations of up to 40%. Beyond 40%, a significant reduction in SNR is observed. Scalar-coupling based {sup 1}H-{sup 15}N correlation experiments yield a nearly constant SNR for samples prepared with {<=}30% H{sub 2}O. Samples in which more H{sub 2}O is employed for crystallization show a significantly reduced NMR intensity. Calculation of the SNR by taking into account the reduction in {sup 1}H T{sub 1} in samples containing more protons (SNR per unit time), yields a maximum SNR for samples crystallized using 30 and 40% H{sub 2}O for scalar and dipolar coupling based experiments, respectively. A sensitivity gain of 3.8 is obtained by increasing the H{sub 2}O concentration from 10 to 40% in the CP based experiment, whereas the linewidth only becomes 1.5 times broader. In general, we find that CP is more favorable compared to INEPT based transfer when the number of possible {sup 1}H,{sup 1}H interactions increases. At low levels of deuteration ({>=}60% H{sub 2}O in the crystallization buffer), resonances from rigid residues are broadened beyond detection. All experiments are carried out at MAS frequency of 24 kHz employing perdeuterated samples of the chicken {alpha}-spectrin SH3 domain.

  11. Chemometric analysis applied in 1H HR-MAS NMR and FT-IR data for chemotaxonomic distinction of intact lichen samples

    This paper describes the potentiality of chemometric analysis applied in 1H HR-MAS NMR and FT-IR data for lichen chemotaxonomic investigations. Lichens present a difficult morphologic differentiation and the chemical analyses are frequently employed for their taxonomic classification, mainly due to the secondary metabolites to be relatively constant for these organisms. The lichen chemotaxonomic classification is usually carried out by color reactions, chromatography, fluorescence and mass spectrometry analysis, where the identification is obtained by one or more techniques. There are some papers which use the carbohydrate content in chemotaxonomy investigation. However, the majority of these techniques involve laborious and time consuming sample pre-treatment. This work focuses on application of 1H high resolution magic angle spinning - nuclear magnetic resonance (HR-MAS NMR) and Fourier transform infrared (FT-IR) associated with chemometric analysis to intact samples. In comparison to other traditional techniques, 1H HR-MAS NMR and FT-IR allied with chemometrics provided a fast and economic method for lichen chemotaxonomy. Both methods were useful for lichen analysis and permitted the satisfactory distinction among families, genera and species, although better results were achieved for FT-IR data

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

    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-Mn2+ 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

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

    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.

  14. Solid state structure by X-ray and 13C CP/MAS NMR of new 5-[2-(N,N-dimethylamino)ethoxy]-4,7-dimethylcoumarins

    Ostrowska, Kinga; Maciejewska, Dorota; Dobrzycki, Łukasz; Socha, Pawel

    2016-05-01

    5-[2-(N,N-dimethylamino)ethoxy]-4,7-dimethylcoumarin (1) and 6-acetyl-5-[2-(N,N-dimethylamino)ethoxy]-4,7-dimethylcoumarin (2), structurally related, were synthesized using both conventional and microwave-assisted approach. An impact of acetyl groups on the molecular structure of coumarin derivatives has been examined. Crystals of 2 were investigated using single crystal and powder X-ray diffraction techniques. Compound 2 crystallizes forming two polymorphs (denoted as 2_1 and 2_2), both belonging to P21/c space group. Both polymorphs are comparably stable and can be formed simultaneously during crystallization process. The solid state structure was also analysed using the fully resolved 13C CP/MAS NMR. The double signals with the intensity ratio of about 1:1 which were observed in the 13C CP/MAS NMR spectrum of compound 1 must arise due to the presence of two conformers of 1. In contrast, NMR spectrum recorded for powder mixture of two polymorphs of compound 2 displays no signal splitting. This is related to structural similarities of molecules in both polymorphs.

  15. Global Fold of Human Cannabinoid Type 2 Receptor Probed by Solid-State 13C-, 15N-MAS NMR and Molecular Dynamics Simulations

    Kimura, Tomohiro; Vukoti, Krishna; Lynch, Diane L.; Hurst, Dow P.; Grossfield, Alan; Pitman, Michael C.; Reggio, Patricia H.; Yeliseev, Alexei A.; Gawrisch, Klaus

    2013-01-01

    The global fold of human cannabinoid type 2 (CB2) receptor in the agonist-bound active state in lipid bilayers was investigated by solid-state 13C- and 15N magic-angle spinning (MAS) NMR, in combination with chemical-shift prediction from a structural model of the receptor obtained by microsecond-long molecular dynamics (MD) simulations. Uniformly 13C-, and 15N-labeled CB2 receptor was expressed in milligram quantities by bacterial fermentation, purified, and functionally reconstituted into l...

  16. The study of a monocotyledon abscission zone using microscopic, chemical, enzymatic and solid state 13C CP/MAS NMR analyses.

    Henderson, J; Davies, H A; Heyes, S J; Osborne, D J

    2001-01-01

    We have investigated distinguishing features in cells of the abscission zone of a monocotyledon fruit, the oil palm Elaeis guineensis. The cell walls of the abscission zone and the subtending mesocarp and pedicel have been analysed by light and transmission electron microscopy, by chemical methods and by solid state 13C CP/MAS NMR spectroscopy. Results show that these abscission zone cells have specific characteristics which include high levels of unmethylated pectin in the walls and an inducible (x35) polygalacturonase enzyme expression. Together these findings help to explain the localised precision of cell separation events. PMID:11219806

  17. Solid state P-31 MAS NMR spectroscopy and conductivity measurements on NbOPO4 and H3PO4 composite materials

    Risskov Sørensen, Daniel; Nielsen, U. G.; Skou, E. M.

    2014-01-01

    .1 and 74.2 M% were produced and characterized with powder X-ray diffraction, P-31 MAS NMR and impedance spectroscopy. NMR revealed that a significant degree of dehydration and vaporization of H3PO4 takes place above 200 degrees C, and increases with temperature. At 500 degrees C the NbOPO4 and H3PO4 has...... reacted to form niobium pyrophosphate (Nb2P4O15). Impedance spectroscopy showed an increase in conductivity with increasing acid concentration, whereas the conductivity decreased slightly with increasing temperature. The highest conductivity measured was 2.5.10(-3) S/cm for a sample containing 74.2 M% of...

  18. 1H-MAS-NMR Chemical Shifts in Hydrogen-Bonded Complexes of Chlorophenols (Pentachlorophenol, 2,4,6-Trichlorophenol, 2,6-Dichlorophenol, 3,5-Dichlorophenol, and p-Chlorophenol) and Amine, and H/D Isotope Effects on 1H-MAS-NMR Spectra

    Hisashi Honda

    2013-01-01

    Chemical shifts (CS) of the 1H nucleus in N···H···O type hydrogen bonds (H-bond) were observed in some complexes between chlorophenols [pentachlorophenol (PCP), 2,4,6-tricholorophenol (TCP), 2,6-dichlorophenol (26DCP), 3,5-dichlorophenol (35DCP), and p-chlorophenol (pCP)] and nitrogen-base (N-Base) by solid-state high-resolution 1H-NMR with the magic-angle-spinning (MAS) method. Employing N-Bases with a wide range of pKa values (0.65–10.75), 1H-MAS-NMR CS values of bridging H atoms in H-bonds...

  19. 1H-MAS-NMR Chemical Shifts in Hydrogen-Bonded Complexes of Chlorophenols (Pentachlorophenol, 2,4,6-Trichlorophenol, 2,6-Dichlorophenol, 3,5-Dichlorophenol, and p-Chlorophenol and Amine, and H/D Isotope Effects on 1H-MAS-NMR Spectra

    Hisashi Honda

    2013-04-01

    Full Text Available Chemical shifts (CS of the 1H nucleus in N···H···O type hydrogen bonds (H-bond were observed in some complexes between chlorophenols [pentachlorophenol (PCP, 2,4,6-tricholorophenol (TCP, 2,6-dichlorophenol (26DCP, 3,5-dichlorophenol (35DCP, and p-chlorophenol (pCP] and nitrogen-base (N-Base by solid-state high-resolution 1H-NMR with the magic-angle-spinning (MAS method. Employing N-Bases with a wide range of pKa values (0.65–10.75, 1H-MAS-NMR CS values of bridging H atoms in H-bonds were obtained as a function of the N-Base’s pKa. The result showed that the CS values were increased with increasing pKa values in a range of DpKa 2: The maximum CS values was recorded in the PCP (pKa = 5.26–4-methylpyridine (6.03, TCP (6.59–imidazole (6.99, 26DCP (7.02–2-amino-4-methylpyridine (7.38, 35DCP (8.04–4-dimethylaminopyridine (9.61, and pCP (9.47–4-dimethylaminopyridine (9.61 complexes. The largest CS value of 18.6 ppm was recorded in TCP–imidazole crystals. In addition, H/D isotope effects on 1H-MAS-NMR spectra were observed in PCP–2-amino-3-methylpyridine. Based on the results of CS simulation using a B3LYP/6-311+G** function, it can be explained that a little changes of the N–H length in H-bond contribute to the H/D isotope shift of the 1H-MAS-NMR peaks.

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

    Emami, Sanaz; Fan Ying; Munro, Rachel; Ladizhansky, Vladimir; Brown, Leonid S., E-mail: lebrown@uoguelph.ca [University of Guelph, Departments of Physics, and Biophysics Interdepartmental Group (Canada)

    2013-02-15

    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 ({sup 13}C/{sup 15}N) isotopically labeled in this system and functionally reconstituted into phospholipids, giving excellent resolution of solid-state magic angle spinning NMR spectra.

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

    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 (13C/15N) isotopically labeled in this system and functionally reconstituted into phospholipids, giving excellent resolution of solid-state magic angle spinning NMR spectra.

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

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

    2016-04-04

    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.

  3. XRD, FTIR and 13C CP/ MAS NMR Studies of Composite Comprising Poly(vinyl acetate)- silylated Si-MCM-41

    A composite structure based on silylated MCM-41 and Poly(vinyl acetate) (PVAc) was synthesized via solution intercalation. Poly(vinyl acetate)-silylated Si- MCM-41 composite were characterized by XRD, FTIR spectroscopy and 13C CP/ MAS NMR in order to determine the compatibility between PVAc and the silicate host. XRD study reveals that the framework of silylated Si-MCM-41 was not altered upon incorporation of PVAc. FTIR study showed that characteristic peak assigned to carbonyl group in PVAc was observed around 1741.6 cm-1 for all the composites indicating the presence of PVAc in the silylated Si-MCM-41. 13C CP/ MAS NMR showed the increase of line width of the peak assigned to C=O carbonyl group indicating the increase in randomness of polymer chains in confined space. The shifting of the C=O carbonyl groups is a sign of the change in chemical environment of the carbonyl owing to the interaction of PVAc with the silica matrix of silylated Si-MCM-41. (author)

  4. Modification of molybdenum structural environment in borosilicate glasses with increasing content of boron and calcium oxide by 95Mo MAS NMR

    In nuclear borosilicate glasses, when molybdenum is in too high concentration and when it combines with other elements such as alkali and alkaline-earth elements it may form crystalline molybdates, including sodium molybdate, Na2MoO4, during melt cooling. In a nuclear vitrification context, the origin of this phenomenon must be understood to control and to avoid the appearance of this water-soluble crystalline phase. The solubility limit of MoO3 was found to be 2.5 mol% in a simplified SiO2-B2O3-Na2O-CaO nuclear glass at about 1300 degrees C. Higher MoO3 concentrations induced liquid phase separation followed by crystallization of Na2MoO4 and CaMoO4. This study assessed the impact of increasing the CaO and B2O3 content on the tendency of the melts to crystallize and the impact on the glass network structure. Structural analysis (Mo-95 MAS NMR and B-11 MAS NMR) of several glass series and standard SiO2-Na2O-MoO3 or SiO2-CaO-MoO3 glass showed that the nature of the crystallized phases that may appear during cooling of the melt can be controlled by correlation of the proportion of Na+ cations remaining free in the glass network with the soda/lime environment of tetrahedral MoO42- entities. (authors)

  5. Modification of Molybdenum Structural Environment in Borosilicate Glasses with Increasing Content of Boron and Calcium Oxide by 95Mo MAS NMR

    In nuclear borosilicate glasses, when molybdenum is in too high concentration and when it combines with other elements such as alkali and alkaline-earth elements it may form crystalline molybdates, including sodium molybdate, Na2MoO4, during melt cooling. In a nuclear vitrification context, the origin of this phenomenon must be understood to control and to avoid the appearance of this water-soluble crystalline phase. The solubility limit of MoO3 was found to be 2.5 mol% in a simplified SiO2-B2O3-Na2O-CaO nuclear glass at about 1300 degrees C. Higher MoO3 concentrations induced liquid phase separation followed by crystallization of Na2MoO4 and CaMoO4. This study assessed the impact of increasing the CaO and B2O3 content on the tendency of the melts to crystallize and the impact on the glass network structure. Structural analysis (95Mo MAS NMR and 11B MAS NMR) of several glass series and standard SiO2-Na2O-MoO3 or SiO2-CaO-MoO3 glass showed that the nature of the crystallized phases that may appear during cooling of the melt can be controlled by correlation of the proportion of Na+ cations remaining free in the glass network with the soda/lime environment of tetrahedral MoO42- entities. (authors)

  6. 15N Photo-CIDNP MAS NMR To Reveal Functional Heterogeneity in Electron Donor of Different Plant Organisms

    Janssen, Geertje J.; Roy, Esha; Matysik, Jörg; Alia, A.

    2011-01-01

    In plants and cyanobacteria, two light-driven electron pumps, photosystems I and II (PSI, PSII), facilitate electron transfer from water to carbon dioxide with quantum efficiency close to unity. While similar in structure and function, the reaction centers of PSI and PSII operate at widely different potentials with PSI being the strongest reducing agent known in living nature. Photochemically induced dynamic nuclear polarization (photo-CIDNP) in magic-angle spinning (MAS) nuclear magnetic res...

  7. Constant-time 2D and 3D through-bond correlation NMR spectroscopy of solids under 60 kHz MAS

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy, E-mail: ramamoor@umich.edu [Biophysics and Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055 (United States)

    2016-01-21

    Establishing connectivity and proximity of nuclei is an important step in elucidating the structure and dynamics of molecules in solids using magic angle spinning (MAS) NMR spectroscopy. Although recent studies have successfully demonstrated the feasibility of proton-detected multidimensional solid-state NMR experiments under ultrafast-MAS frequencies and obtaining high-resolution spectral lines of protons, assignment of proton resonances is a major challenge. In this study, we first re-visit and demonstrate the feasibility of 2D constant-time uniform-sign cross-peak correlation (CTUC-COSY) NMR experiment on rigid solids under ultrafast-MAS conditions, where the sensitivity of the experiment is enhanced by the reduced spin-spin relaxation rate and the use of low radio-frequency power for heteronuclear decoupling during the evolution intervals of the pulse sequence. In addition, we experimentally demonstrate the performance of a proton-detected pulse sequence to obtain a 3D {sup 1}H/{sup 13}C/{sup 1}H chemical shift correlation spectrum by incorporating an additional cross-polarization period in the CTUC-COSY pulse sequence to enable proton chemical shift evolution and proton detection in the incrementable t{sub 1} and t{sub 3} periods, respectively. In addition to through-space and through-bond {sup 13}C/{sup 1}H and {sup 13}C/{sup 13}C chemical shift correlations, the 3D {sup 1}H/{sup 13}C/{sup 1}H experiment also provides a COSY-type {sup 1}H/{sup 1}H chemical shift correlation spectrum, where only the chemical shifts of those protons, which are bonded to two neighboring carbons, are correlated. By extracting 2D F1/F3 slices ({sup 1}H/{sup 1}H chemical shift correlation spectrum) at different {sup 13}C chemical shift frequencies from the 3D {sup 1}H/{sup 13}C/{sup 1}H spectrum, resonances of proton atoms located close to a specific carbon atom can be identified. Overall, the through-bond and through-space homonuclear/heteronuclear proximities determined from the

  8. Constant-time 2D and 3D through-bond correlation NMR spectroscopy of solids under 60 kHz MAS

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy

    2016-01-01

    Establishing connectivity and proximity of nuclei is an important step in elucidating the structure and dynamics of molecules in solids using magic angle spinning (MAS) NMR spectroscopy. Although recent studies have successfully demonstrated the feasibility of proton-detected multidimensional solid-state NMR experiments under ultrafast-MAS frequencies and obtaining high-resolution spectral lines of protons, assignment of proton resonances is a major challenge. In this study, we first re-visit and demonstrate the feasibility of 2D constant-time uniform-sign cross-peak correlation (CTUC-COSY) NMR experiment on rigid solids under ultrafast-MAS conditions, where the sensitivity of the experiment is enhanced by the reduced spin-spin relaxation rate and the use of low radio-frequency power for heteronuclear decoupling during the evolution intervals of the pulse sequence. In addition, we experimentally demonstrate the performance of a proton-detected pulse sequence to obtain a 3D 1H/13C/1H chemical shift correlation spectrum by incorporating an additional cross-polarization period in the CTUC-COSY pulse sequence to enable proton chemical shift evolution and proton detection in the incrementable t1 and t3 periods, respectively. In addition to through-space and through-bond 13C/1H and 13C/13C chemical shift correlations, the 3D 1H/13C/1H experiment also provides a COSY-type 1H/1H chemical shift correlation spectrum, where only the chemical shifts of those protons, which are bonded to two neighboring carbons, are correlated. By extracting 2D F1/F3 slices (1H/1H chemical shift correlation spectrum) at different 13C chemical shift frequencies from the 3D 1H/13C/1H spectrum, resonances of proton atoms located close to a specific carbon atom can be identified. Overall, the through-bond and through-space homonuclear/heteronuclear proximities determined from the 3D 1H/13C/1H experiment would be useful to study the structure and dynamics of a variety of chemical and biological

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

    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

  10. Two-dimensional MAS NMR correlation protocols involving double-quantum filtering of quadrupolar spin-pairs.

    Edén, Mattias

    2010-05-01

    Three two-dimensional (2D) NMR homonuclear correlation techniques invoking double-quantum (2Q) filtration of the central transitions of half-integer spins are evaluated numerically and experimentally. They correlate directly detected single-quantum (1Q) coherences in the t(2) domain with either of 1Q, two-spin 2Q or single-spin multiple-quantum coherence-evolutions in the indirect (t(1)) dimension. We employ experimental (23)Na and (27)Al NMR on sodium sulfite and the natural mineral sillimanite (SiAl(2)O(5)), in conjunction with simulated 2D spectra from pairs of dipolar-recoupled spins-3/2 and 5/2 at different external magnetic fields, to compare the correlation strategies from the viewpoints of 2D spectral resolution, signal sensitivity, implementational aspects and their relative merits for establishing internuclear proximities and quadrupolar tensor orientations. PMID:20202872

  11. (14)N overtone NMR under MAS: signal enhancement using symmetry-based sequences and novel simulation strategies.

    Haies, Ibraheem M; Jarvis, James A; Bentley, Harry; Heinmaa, Ivo; Kuprov, Ilya; Williamson, Philip T F; Carravetta, Marina

    2015-03-01

    Overtone (14)N NMR spectroscopy is a promising route for the direct detection of (14)N signals with good spectral resolution. Its application is currently limited, however, by the absence of efficient polarization techniques for overtone signal enhancement and the lack of efficient numerical simulation techniques to aid in both the development of new methods and the analysis and interpretation of experimental data. In this paper we report a novel method for the transfer of polarization from (1)H to the (14)N overtone using symmetry-based R-sequences that overcome many of the limitations of adiabatic approaches that have worked successfully on static samples. Refinement of these sequences and the analysis of the resulting spectra have been facilitated through the development of an efficient simulation strategy for (14)N overtone NMR spectroscopy of spinning samples, using effective Hamiltonians on top of Floquet and Fokker-Planck equations. PMID:25662410

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

    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

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

    A soil incubated for 34 days in the absence (control) and presence (treated) of uniformly labelled 13C-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 13C n.m.r. (cross polarization/magic angle spinning 13C 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 13C 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

  14. Structural investigations of PuIII phosphate by X-ray diffraction, MAS-NMR and XANES spectroscopy

    Popa, Karin; Raison, Philippe E.; Martel, Laura; Martin, Philippe M.; Prieur, Damien; Solari, Pier L.; Bouëxière, Daniel; Konings, Rudy J. M.; Somers, Joseph

    2015-10-01

    PuPO4 was prepared by a solid state reaction method and its crystal structure at room temperature was solved by powder X-ray diffraction combined with Rietveld refinement. High resolution XANES measurements confirm the +III valence state of plutonium, in agreement with valence bond derivation. The presence of the americium (as β- decay product of plutonium) in the +III oxidation state was determined based on XANES spectroscopy. High resolution solid state 31P NMR agrees with the XANES results and the presence of a solid-solution.

  15. Structural investigations of PuIII phosphate by X-ray diffraction, MAS-NMR and XANES spectroscopy

    POPA KARIN; RAISON Philippe; MARTEL LAURA; Martin, Philippe; PRIEUR DAMIEN; SOLARI Pier-Lorenzo; BOUEXIERE Daniel; KONINGS Rudy; SOMERS Joseph

    2015-01-01

    PuPO4 was prepared by a solid state reaction method and its crystal structure at room temperature was solved by powder X-ray diffraction combined with Rietveld refinement. High resolution XANES measurements confirm the +III valence state of plutonium, in agreement with valence bond derivation. The presence of the americium (as beta- decay product of plutonium) in the +III oxidation state was determined based on XANES results. High resolution solid state 31P NMR seems to agree with the XANES r...

  16. Insights into a lipid regulator by solid-state MAS NMR : kinetic and structure-functional studies on diacylglycerol kinase

    Ullrich, Sandra Johanna

    2013-01-01

    In this thesis the integral membrane protein diacylglycerol kinase (DAGK) from E.coli is investigated with solid-state NMR. The aim is to gain an insight into the enzyme’s mechanism through integration of kinetic, structural and dynamic data. The biological function of DAGK is the transfer of the γ-phosphate group from Mg*ATP to diacylglycerol (DAG) building phosphatidic acid (PA)[6] as port of the membrane-derived oligosaccharide cycle[31,34]. Surprisingly, DAGK does not share structural or ...

  17. Investigation of the Structure and Active Sites of TiO2 Nanorod Supported VOx Catalysts by High-Field and Fast-Spinning 51V MAS NMR

    Hu, Jian Z.; Xu, Suochang; Li, Weizhen; Hu, Mary Y.; Deng, Xuchu; Dixon, David A.; Vasiliu, Monica; Craciun, Raluca; Wang, Yong; Bao, Xinhe; Peden, Charles HF

    2015-07-02

    Supported VOx/TiO2-Rod catalysts were studied by 51V MAS NMR at high field using a sample spinning rate of 55 kHz. The superior spectral resolution allows for the observation of at least five vanadate species. The assignment of these vanadate species was carried out by quantum mechanical calculations of 51V NMR chemical shifts of model V-surface structures. Methanol oxidative dehydrogenation (ODH) was used to establish the correlation between the reaction rate and the various surface V-sites. It is found that monomeric V-species dominated the catalyst at low vanadium loadings with two peaks observed at about -502 and -529 ppm. V-dimers with two bridged oxygen appeare at about -555 ppm. Vanadate dimers and polyvanadates connected by one bridged oxygen atom between two adjacent V atoms resonate at about -630 ppm. A positive correlation is found between the V-dimers related to the -555 ppm peak and the ODH rate while a better correlation is obtained by including monomeric contributions. This result indicates that surface V-dimers related to the -555 ppm peak are the major active sites for ODH reaction despite mono-V species are more catalytic active but their relative ratios are decreased dramatically at high V-loadings. Furthermore, a portion of the V-species is found invisible. In particular, the level of such invisibility increases with decreased level of V-loading, suggesting the existence of paramagnetic V-species at the surface.

  18. Hybridizing cross-polarization with NOE or refocused-INEPT enhances the sensitivity of MAS NMR spectroscopy

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

    2016-05-01

    Heteronuclear cross polarization (CP) has been commonly used to enhance the sensitivity of dilute low-γ nuclei in almost all solid-state NMR experiments. However, CP relies on heteronuclear dipolar couplings, and therefore the magnetization transfer efficiency becomes inefficient when the dipolar couplings are weak, as is often the case for mobile components in solids. Here, we demonstrate methods that combine CP with heteronuclear Overhauser effect (referred to as CP-NOE) or with refocused-INEPT (referred to as CP-RINEPT) to overcome the efficiency limitation of CP and enhance the signal-to-noise ratio (S/N) for mobile components. Our experimental results reveal that, compared to the conventional CP, significant S/N ratio enhancement can be achieved for resonances originating from mobile components, whereas the resonance signals associated with rigid groups are not significantly affected due to their long spin-lattice relaxation times. In fact, the S/N enhancement factor is also dependent on the temperature, CP contact time as well as on the system under investigation. Furthermore, we also demonstrate that CP-RINEPT experiment can be successfully employed to independently detect mobile and rigid signals in a single experiment without affecting the data collection time. However, the resolution of CP spectrum obtained from the CP-RINEPT experiment could be slightly compromised by the mandatory use of continuous wave (CW) decoupling during the acquisition of signals from rigid components. In addition, CP-RINEPT experiment can be used for spectral editing utilizing the difference in dynamics of different regions of a molecule and/or different components present in the sample, and could also be useful for the assignment of resonances from mobile components in poorly resolved spectra. Therefore, we believe that the proposed approaches are beneficial for the structural characterization of multiphase and heterogeneous systems, and could be used as a building block in

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

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

    2005-01-01

    system representing an ideal model system for NMR studies. 6Li resonances with large hyperfine shifts (approximately 145 ppm) were observed above the goethite point of zero charge, providing clear evidence for the presence of Li-O-Fe connectivities, and thus the formation of an inner sphere Li+ complex...... 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...

  20. Effect of organic matter application on CP-MAS-13C-NMR spectra of humic acids from a brown soil

    Dou, S.

    2009-04-01

    The humified SOM or humic substances (HS) composed of humic acid (HA), fulvic acid (FA) and humin (HM) represent the most microbially recalcitrant and stable reservoir of organic carbon in soil (Piccolo et al., 2004). OM applications can influence the amount and structural characteristics of HS(Dou et al., 2008). During the past few decades, there has been much research on HS, but their chemical structure is still not fully understood (Dong, 2006).CP-MAS-13C-NMR spectroscopy was considered as an effective method to study structures of HS without dissolving problem compared with liquid 13C-NMR (Conte et al., 1997; Dou et al., 2008). It can directly measure the carbon framework and reflect the nature of HS transformation after OM application (Spaccini et al., 2000). For that reason, this method was applied in this study. The objective of this paper was to clarify the effect of long term OM application on the changes of structural characteristics in HAs, which provided new information for improving soil fertility by OM application. The experiment was carried out on a brown soil (Paleudalf in USDA Soil Taxonomy) at Shenyang Agricultural University, Liaoning province, China (N41°48'-E123°25'). The experiment included 3 treatments: zero-treatment (CKbr), and two pig manure (PM) treatments (O1 and O2) at the rates of 0.9 t ha-1 and 1.8 t ha-1 of organic carbon, respectively. The samples of the HA fraction were extracted, separated and purified according to the method described by Dou et al. (1991). Elemental composition, Differential thermal analysis (DTA), -lgK value, FT-IR and CP-MAS- 13C-NMR of HAs were performed. Effects on the contents of orgaic carbon and its composition. The contents of TOC were from 8.77 g kg-1 to 12.25 g kg-1. The relative contents in TOC for WSS, HA, and FA were 6.87%, 14.2% and 19.8%. Comparing the CKbr, the contents of WSS, HA and FA for O1 and O2 increased, but relative contents of WSS and FA decreased. The content of the HA increased after

  1. 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

    The area intensity change of C1, C4, and C6 in spectrum obtained by 13C 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

  2. Amino-acid selective experiments on uniformly 13C and 15N labeled proteins by MAS NMR: Filtering of lysines and arginines

    Jehle, Stefan; Rehbein, Kristina; Diehl, Anne; van Rossum, Barth-Jan

    2006-12-01

    Amino-acid selective magic-angle spinning (MAS) NMR experiments can aid the assignment of ambiguous cross-peaks in crowded spectra of solid proteins. In particular for larger proteins, data analysis can be hindered by severe resonance overlap. In such cases, filtering techniques may provide a good alternative to site-specific spin-labeling to obtain unambiguous assignments that can serve as starting points in the assignment procedure. In this paper we present a simple pulse sequence that allows selective excitation of arginine and lysine residues. To achieve this, we make use of a combination of specific cross-polarization for selective excitation [M. Baldus, A.T. Petkova, J. Herzfeld, R.G. Griffin, Cross polarization in the tilted frame: assignment and spectral simplification in heteronuclear spin systems, Mol. Phys. 95 (1998) 1197-1207.] and spin diffusion for transfer along the amino-acid side-chain. The selectivity of the filter is demonstrated with the excitation of lysine and arginine side-chain resonances in a uniformly 13C and 15N labeled protein preparation of the α-spectrin SH3 domain. It is shown that the filter can be applied as a building block in a 13C- 13C lysine-only correlation experiment.

  3. {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

    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.

  4. Assigning large proteins in the solid state: a MAS NMR resonance assignment strategy using selectively and extensively {sup 13}C-labelled proteins

    Higman, Victoria A. [Leibniz-Institut fuer Molekulare Pharmakologie (Germany); Flinders, Jeremy [Genentech, Inc., Structural Biology Department (United States); Hiller, Matthias; Jehle, Stefan; Markovic, Stefan; Fiedler, Sebastian; Rossum, Barth-Jan van; Oschkinat, Hartmut [Leibniz-Institut fuer Molekulare Pharmakologie (Germany)], E-mail: oschkinat@fmp-berlin.de

    2009-08-15

    In recent years, solid-state magic-angle spinning nuclear magnetic resonance spectroscopy (MAS NMR) has been growing into an important technique to study the structure of membrane proteins, amyloid fibrils and other protein preparations which do not form crystals or are insoluble. Currently, a key bottleneck is the assignment process due to the absence of the resolving power of proton chemical shifts. Particularly for large proteins (approximately >150 residues) it is difficult to obtain a full set of resonance assignments. In order to address this problem, we present an assignment method based upon samples prepared using [1,3-{sup 13}C]- and [2-{sup 13}C]-glycerol as the sole carbon source in the bacterial growth medium (so-called selectively and extensively labelled protein). Such samples give rise to higher quality spectra than uniformly [{sup 13}C]-labelled protein samples, and have previously been used to obtain long-range restraints for use in structure calculations. Our method exploits the characteristic cross-peak patterns observed for the different amino acid types in {sup 13}C-{sup 13}C correlation and 3D NCACX and NCOCX spectra. An in-depth analysis of the patterns and how they can be used to aid assignment is presented, using spectra of the chicken {alpha}-spectrin SH3 domain (62 residues), {alpha}B-crystallin (175 residues) and outer membrane protein G (OmpG, 281 residues) as examples. Using this procedure, over 90% of the C{alpha}, C{beta}, C' and N resonances in the core domain of {alpha}B-crystallin and around 73% in the flanking domains could be assigned (excluding 24 residues at the extreme termini of the protein)

  5. Assigning large proteins in the solid state: a MAS NMR resonance assignment strategy using selectively and extensively 13C-labelled proteins

    In recent years, solid-state magic-angle spinning nuclear magnetic resonance spectroscopy (MAS NMR) has been growing into an important technique to study the structure of membrane proteins, amyloid fibrils and other protein preparations which do not form crystals or are insoluble. Currently, a key bottleneck is the assignment process due to the absence of the resolving power of proton chemical shifts. Particularly for large proteins (approximately >150 residues) it is difficult to obtain a full set of resonance assignments. In order to address this problem, we present an assignment method based upon samples prepared using [1,3-13C]- and [2-13C]-glycerol as the sole carbon source in the bacterial growth medium (so-called selectively and extensively labelled protein). Such samples give rise to higher quality spectra than uniformly [13C]-labelled protein samples, and have previously been used to obtain long-range restraints for use in structure calculations. Our method exploits the characteristic cross-peak patterns observed for the different amino acid types in 13C-13C correlation and 3D NCACX and NCOCX spectra. An in-depth analysis of the patterns and how they can be used to aid assignment is presented, using spectra of the chicken α-spectrin SH3 domain (62 residues), αB-crystallin (175 residues) and outer membrane protein G (OmpG, 281 residues) as examples. Using this procedure, over 90% of the Cα, Cβ, C' and N resonances in the core domain of αB-crystallin and around 73% in the flanking domains could be assigned (excluding 24 residues at the extreme termini of the protein)

  6. 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

    A series of complexes of 1-phenyldibenzophosphole (DBP), 1-phenyl-3,4,-dimethylphosphole (DMPP), and triphenylphosphine of the type LnAuX (n = 1, L = DBP, DMPP, Ph3P, X = Cl, Br, I; n = 3, L = DBP, X = Cl, Br, I; n = 3, L = Ph3P, X = Cl; n = 4, L = DBP, DMPP, X = PF6) have been prepared and characterized. The structures of (DBP)AuCl (1), (DBP)3AuCl (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 31P(1H) NMR spectrum of complex 1 shows two resonances in a 1:1 intensity ratio, and the CP/MAS 31P(1H) 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 Cs symmetry as evidenced by the observation of two 31P resonances in a 2:1 intensity ratio in its CP/MAS 31P(1H) NMR spectrum. Variable-temperature 31P(1H) 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

  7. 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

    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.

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

    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: 4.493, year: 2014 http://pubs.rsc.org/en/content/articlepdf/2015/cp/c5cp04475h

  9. Efficient and facile Ar-Si bond cleavage by montmorillonite KSF: synthetic and mechanistic aspects of solvent-free protodesilylation studied by solution and solid-state MAS NMR.

    Zafrani, Yossi; Gershonov, Eytan; Columbus, Ishay

    2007-08-31

    A facile and efficient method for the cleavage of the Ar-Si bond of various aryl trimethyl silanes is described. When adsorbed on montmorillonite KSF (mont KSF), these arylsilanes readily undergo a solvent-free protodesilylation to the corresponding arenes at room temperature in excellent yields. This approach seems to be superior to the traditional mild methods (i.e., desilylation by TFA, TBAF, CsF), in terms of reaction yield, rate, and environmentally benign conditions. Some mechanistic studies using both solution and solid-state magic-angle spinning (SS MAS) (1)H NMR are also presented. PMID:17676903

  10. Detection of dynamic water molecules in a microcrystalline sample of the SH3 domain of {alpha}-spectrin by MAS solid-state NMR

    Chevelkov, Veniamin [Forschungsinstitut fuer Molekulare Pharmakologie (FMP) (Germany); Faelber, Katja [Max-Delbrueck-Centrum fuer Molekulare Medizin (Germany); Diehl, Anne [Forschungsinstitut fuer Molekulare Pharmakologie (FMP) (Germany); Heinemann, Udo [Max-Delbrueck-Centrum fuer Molekulare Medizin (Germany); Oschkinat, Hartmut; Reif, Bernd [Forschungsinstitut fuer Molekulare Pharmakologie (FMP) (Germany)], E-mail: reif@fmp-berlin.de

    2005-04-15

    Water molecules are a major determinant of protein stability and are important for understanding protein-protein interactions. We present two experiments which allow to measure first the effective T{sub 2} decay rate of individual amide proton, and second the magnetization build-up rates for a selective transfer from H{sub 2}O to H{sup N} using spin diffusion as a mixing element. The experiments are demonstrated for a uniformly {sup 2}H, {sup 15}N labeled sample of a microcrystalline SH3 domain in which exchangeable deuterons were back-substituted with protons. In order to evaluate the NMR experimental data, as X-ray structure of the protein was determined using the same crystallization protocol as for the solid-state NMR sample. The NMR experimental data are correlated with the dipolar couplings calculated from H{sub 2}O-H{sup N} distances which were extracted from the X-ray structure of the protein. We find that the H{sup N}T{sub 2} decay rates and H{sub 2}O-H{sup N} build-up rates are sensitive to distance and dynamics of the detected water molecules with respect to the protein. We show that qualitative information about localization and dynamics of internal water molecules can be obtained in the solid-state by interpretation of the spin dynamics of a reporter amide proton.

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

    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.

  12. Carbonation of C–S–H and C–A–S–H samples studied by {sup 13}C, {sup 27}Al and {sup 29}Si MAS NMR spectroscopy

    Sevelsted, Tine F.; Skibsted, Jørgen, E-mail: jskib@chem.au.dk

    2015-05-15

    Synthesized calcium silicate hydrate (C–S–H) samples with Ca/Si ratios of 0.66, 1.0, and 1.5 have been exposed to atmospheric CO{sub 2} at room temperature and high relative humidity and studied after one to 12 weeks. {sup 29}Si NMR reveals that the decomposition of C–S–H caused by carbonation involves two steps and that the decomposition rate decreases with increasing Ca/Si ratio. The first step is a gradual decalcification of the C–S–H where calcium is removed from the interlayer and defect sites in the silicate chains until Ca/Si = 0.67 is reached, ideally corresponding to infinite silicate chains. In the seconds step, calcium from the principal layers is consumed, resulting in the final decomposition of the C–S–H and the formation of an amorphous silica phase composed of Q{sup 3} and Q{sup 4} silicate tetrahedra. The amount of solid carbonates and of carbonate ions in a hydrous environment increases with increasing Ca/Si ratio for the C–S–H, as shown by {sup 13}C NMR. For C–A–S–H samples with Ca/Si = 1.0 and 1.5, {sup 27}Al NMR demonstrates that all aluminium sites associated with the C–S–H are consumed during the carbonation reactions and incorporated mainly as tetrahedral Al(–OSi){sub 4} units in the amorphous silica phase. A small amount of penta-coordinated Al sites has also been identified in the silica phase.

  13. Carbonation of C–S–H and C–A–S–H samples studied by 13C, 27Al and 29Si MAS NMR spectroscopy

    Synthesized calcium silicate hydrate (C–S–H) samples with Ca/Si ratios of 0.66, 1.0, and 1.5 have been exposed to atmospheric CO2 at room temperature and high relative humidity and studied after one to 12 weeks. 29Si NMR reveals that the decomposition of C–S–H caused by carbonation involves two steps and that the decomposition rate decreases with increasing Ca/Si ratio. The first step is a gradual decalcification of the C–S–H where calcium is removed from the interlayer and defect sites in the silicate chains until Ca/Si = 0.67 is reached, ideally corresponding to infinite silicate chains. In the seconds step, calcium from the principal layers is consumed, resulting in the final decomposition of the C–S–H and the formation of an amorphous silica phase composed of Q3 and Q4 silicate tetrahedra. The amount of solid carbonates and of carbonate ions in a hydrous environment increases with increasing Ca/Si ratio for the C–S–H, as shown by 13C NMR. For C–A–S–H samples with Ca/Si = 1.0 and 1.5, 27Al NMR demonstrates that all aluminium sites associated with the C–S–H are consumed during the carbonation reactions and incorporated mainly as tetrahedral Al(–OSi)4 units in the amorphous silica phase. A small amount of penta-coordinated Al sites has also been identified in the silica phase

  14. Elemental and structural analysis of silicon forms in herbal drugs using silicon-29 MAS NMR and WD-XRF spectroscopic methods.

    Pajchel, L; Nykiel, P; Kolodziejski, W

    2011-12-01

    The objective of this work was to study concentration of silicon and its structural forms present in herbal drugs. Equisetum arvense and Urtica dioica L. from teapot bags, dietary supplements (tablets and capsules) containing those herbs, dry extract obtained from a teapot bag of E. arvense, and samples of the latter herb harvested in wild habitat over four months were studied using wavelength dispersive X-ray spectroscopy (WD-XRF) and high-resolution solid-state (29)Si NMR. The highest concentration of Si, ca. 27mg/g, was found in the herbal material from the teapot bags containing E. arvense. The Si content in natural E. arvense (whole plants) increased from May to August by ca. 7mg/g, reaching value 26mg/g. Three different silicon forms were detected in the studied herbal samples: Si(OSi)4 (Q(4)), Si(OH)(OSi)3 (Q(3)) and Si(OH)2(OSi)2 (Q(2)). Those sites were populated in E. arvense in the following order: Q(4)≫Q(3)>Q(2). A dramatic, ca. 50-fold decrease of the Si concentration during the infusion process was observed. The infusion process and the subsequent drying procedure augmented population of the Q(4) sites at the cost of the Q(2) sites. The WD-XRF and (29)Si NMR methods occurred useful and complementary in the study of herbal materials. PMID:21813258

  15. Investigation of Pozzolanic Reaction in Nanosilica-Cement Blended Pastes Based on Solid-State Kinetic Models and 29Si MAS NMR

    Jiho Moon

    2016-02-01

    Full Text Available The incorporation of pozzolanic materials in concrete has many beneficial effects to enhance the mechanical properties of concrete. The calcium silicate hydrates in cement matrix of concrete increase by pozzolanic reaction of silicates and calcium hydroxide. The fine pozzolanic particles fill spaces between clinker grains, thereby resulting in a denser cement matrix and interfacial transition zone between cement matrix and aggregates; this lowers the permeability and increases the compressive strength of concrete. In this study, Ordinary Portland Cement (OPC was mixed with 1% and 3% nanosilica by weight to produce cement pastes with water to binder ratio (w/b of 0.45. The specimens were cured for 7 days. 29Si nuclear magnetic resonance (NMR experiments are conducted and conversion fraction of nanosilica is extracted. The results are compared with a solid-state kinetic model. It seems that pozzolanic reaction of nanosilica depends on the concentration of calcium hydroxide.

  16. Inter- and intramolecular distance measurements by solid-state MAS NMR: Determination of gramicidin A channel dimer structure in hydrated phospholipid bilayers

    Fu Riqiang; Cotten, Myriam; Cross, Timothy A. [Center for Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory (United States)

    2000-03-15

    Distance constraints are an important complement to orientational constraints. While a high-resolution monomer structure of the ion channel forming polypeptide, gramicidin A, has been solved with 120 orientational constraints, the precise geometry of the dimer interface has not been characterized. Here, using both {sup 13}C and {sup 15}N labeled gramicidin A samples in hydrated phospholipid bilayers, both inter- and intramolecular distances have been measured with a recently developed simultaneous frequency and amplitude modulation (SFAM) solid-state NMR scheme. Using this approach {sup 15}N-{sup 13}C{sub 1} residual dipolar couplings across a hydrogen bond as small as 20 {+-} 2 Hz have been characterized. While such distances are on the order of 4.2 {+-} 0.2 A, the spectroscopy is complicated by rapid global motion of the molecular structure about the bilayer normal and channel axis. Consequently, the nominal 40 Hz dipolar coupling is averaged depending on the orientation of the internuclear vector with respect to the motional axis. The intermolecular distance confirmed the previously described monomeric structure, while the intramolecular distance across the monomer-monomer interface defined this junction and confirmed the previous model of this interface.

  17. (29)Si, (47)Ti, (49)Ti and (195)Pt solid state MAS NMR spectroscopic investigations of ternary silicides TPtSi, germanides TPtGe (T = Ti, Zr, Hf) and stannide TiPtSn.

    Benndorf, Christopher; Eckert, Hellmut; Pöttgen, Rainer

    2016-05-10

    Eight ternary tetrelides TPtX (T = Ti, Zr, Hf; X = Si, Ge, Sn) were synthesized from the elements by arc-melting and subsequent annealing. TiPtSi, ZrPtSi, ZrPtGe, HfPtSi and HfPtGe crystallize with the orthorhombic TiNiSi type structure, in the space group Pnma. The structures of HfPtSi (a = 654.44(9), b = 387.97(6), c = 750.0(1) pm, wR2 = 0.0592, 411 F(2) values, 20 variables) and HfPtGe (a = 660.36(7), b = 395.18(4), c = 763.05(8) pm, wR2 = 0.0495, 430 F(2) values, 20 variables) were refined from single crystal X-ray diffractometer data. TiPtSn adopts the cubic MgAgAs type. TiPtGe is dimorphic with a TiNiSi type high-temperature modification which transforms to cubic LT-TiPtGe (MgAgAs type). All phases were investigated by high resolution (29)Si, (47)Ti, (49)Ti and (195)Pt solid state MAS NMR spectroscopy. In the cubic compounds, the (47/49)Ti NMR signals are easily detected owing to the absence of quadrupolar broadening effects. The (195)Pt resonances of the orthorhombic compounds are characterized by strongly negative isotropic Knight shifts and large Knight shift anisotropies, whereas positive isotropic Knight shifts and no anisotropies are observed for the cubic compounds. These results indicate that the phase transition in TiPtGe is associated with dramatic changes in the electronic properties. Within each group of isotypic compounds the isotropic (29)Si, (47/49)Ti and (195)Pt Knight shifts show systematic dependences on the transition metal or tetrel atomic number, suggesting that the numerical values are influenced by the electronegativities of the metallic (or metalloid) neighbours. PMID:27097719

  18. Fe/ZSM-5 prepared by sublimination of FeCl{sub 3}: The structure of the Fe species as determined by IR, {sup 27}Al MAS NMR, and EXAFS spectroscopy

    Marturano, P.; Drozdova, L.; Kogelbauer, A.; Prins, R.

    2000-05-15

    The state of the iron in two different Fe/ZSM-5 samples prepared by sublimation of FeCl{sub 3} was investigated by EXAFS, IR, {sup 27}Al MAS NMR, XRD, and nitrogen adsorption measurements. In one Fe/ZSM-54 (Fe/Al = 1) sample, EXAFS revealed for the first time the presence of diferric (hydr)oxo-bridged binuclear clusters, whose structures differ from those postulated in the literature, resembling that of the methane monooxygenase enzyme. IR showed that binuclear Fe complexes are located at the ion-exchange positions of the zeolite, compensating one or two lattice charges. The remainder of the charge-compensating one or two lattice charges. The remainder of the charge-compensating sites are Broensted hydroxyls. On both zeolites, the NMR detection of the framework Al atoms (54 ppm) is strongly perturbed by the paramagnetic effects induced by the Fe ions. The intensity of this peak parallels that of the Broensted hydroxyls in the IR spectra, thus reflecting the presence of Fe species at ion-exchange positions. In a second Fe/ZSM-5 (Fe/Al = 0.8) sample, the iron was present predominantly in the form of large hematite particles (EXAFS, XRD), although a minor fraction of binuclear species might be present as well. The formation of different species seems to be related to different hydrolysis processes occurring on the two zeolites upon washing of the preparation after the sublimation of FeCl{sub 3}. It is also suggested that the final state of the Fe depends on the presence of extraframework Al species as well as the crystallite size of the zeolite used.

  19. 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

    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.

  20. Examination of the structure in solid state of amino analogs of 4,4‧-[1,5-pentanediylbis(oxy)]bisbenzonitrile by means of X-ray diffraction, 13C CP/MAS NMR, and theoretical calculations

    Maciejewska, Dorota; Wolska, Irena; Żabiński, Jerzy

    2008-05-01

    A single crystal of X-ray diffraction structures is presented for 4,4'-[1,5-(3-oxapentanediylbis(amino))]bisbenzonitrile 2 and 4,4'-[1,5-( N-methyl-3-azapentane-diylbis(oxy))]bisbenzonitrile 3. The molecular structures of these derivatives differ especially in conformations of the central linker: in 2 this linker adopts a trans/ gauche conformation, whereas in 3 - a fully extended conformation. The N atoms in various positions of the aliphatic linker change dramatically the molecular packing mode of both bisnitriles. But in both cases the nitrile groups take part in intermolecular hydrogen bonds: a type of N sbnd H···N in 2 and of C sbnd H···N in 3. Various conformations of both molecules were reflected in 13C CP/MAS NMR spectra in solid state as single and double resonance patterns for 2 and 3, respectively. A preliminary anticancer assay against 60 cell lines of 3 reveals strong growth inhibition of leukemia, melanoma, and renal cancer cells.

  1. Evolution of crystalline aluminates from hybrid gel-derived precursors studied by XRD and multinuclear solid-state MAS NMR; I. Celsian, BaAl{sub 2}Si{sub 2}O{sub 8}

    MacKenzie, K.J.D.; Kemmitt, T. [New Zealand Institute for Industrial Research and Development, P.O. Box 31-310, Lower Hutt (New Zealand)

    1999-01-04

    Hybrid gels of celsian composition were prepared from Al alkoxide, tetrathylorthosilicate (TEOS) and Ba acetate and their structure evolution was studied up to 1300C by thermal analysis and X-ray diffraction. Information on their pre-crystallization behaviour was also provided by {sup 27}Al, {sup 29}Si and {sup 137}Ba MAS NMR spectroscopy. Apart from some excess Ba acetate which decomposed to traces of BaCO{sub 3} and BaO by ca. 500C, the gels are X-ray amorphous and relatively homogeneous, and begin to crystallize to hexagonal celsian at 900C. From {approx}500C onwards, an Al-substituted tetrahedral SiO{sub 4} framework begins to be established, evidenced by a progressive increase in the tetrahedral {sup 27}Al sites and the Q{sup 4}(4Al) {sup 29}Si resonance. Migration of Ba into the polyhedral celsian sites occurs much more slowly. A small amount of mullite and Ba{sub 2}SiO{sub 4} which crystallize from Al-rich and Ba-rich regions, respectively, also form crystalline celsian in secondary reactions at ca. 1100C. The observation of a {sup 27}Al shoulder at ca. 36 ppm at 500-900C may arise from Ba-poor mullite-like regions. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  2. Evolution of crystalline aluminates from hybrid gel-derived precursors studied by XRD and multinuclear solid-state MAS NMR; I. Celsian, BaAl2Si2O8

    Hybrid gels of celsian composition were prepared from Al alkoxide, tetrathylorthosilicate (TEOS) and Ba acetate and their structure evolution was studied up to 1300C by thermal analysis and X-ray diffraction. Information on their pre-crystallization behaviour was also provided by 27Al, 29Si and 137Ba MAS NMR spectroscopy. Apart from some excess Ba acetate which decomposed to traces of BaCO3 and BaO by ca. 500C, the gels are X-ray amorphous and relatively homogeneous, and begin to crystallize to hexagonal celsian at 900C. From ∼500C onwards, an Al-substituted tetrahedral SiO4 framework begins to be established, evidenced by a progressive increase in the tetrahedral 27Al sites and the Q4(4Al) 29Si resonance. Migration of Ba into the polyhedral celsian sites occurs much more slowly. A small amount of mullite and Ba2SiO4 which crystallize from Al-rich and Ba-rich regions, respectively, also form crystalline celsian in secondary reactions at ca. 1100C. The observation of a 27Al shoulder at ca. 36 ppm at 500-900C may arise from Ba-poor mullite-like regions. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  3. Experimental (X-ray, (13)C CP/MAS NMR, IR, RS, INS, THz) and Solid-State DFT Study on (1:1) Co-Crystal of Bromanilic Acid and 2,6-Dimethylpyrazine.

    Łuczyńska, Katarzyna; Drużbicki, Kacper; Lyczko, Krzysztof; Dobrowolski, Jan Cz

    2015-06-01

    A combined structural, vibrational spectroscopy, and solid-state DFT study of the hydrogen-bonded complex of bromanilic acid with 2,6-dimethylpyrazine is reported. The crystallographic structure was determined by means of low-temperature single-crystal X-ray diffraction, which reveals the molecular units in their native protonation states, forming one-dimensional infinite nets of moderate-strength O···H-N hydrogen bonds. The nature of the crystallographic forces, stabilizing the studied structure, has been drawn by employing the noncovalent interactions analysis. It was found that, in addition to the hydrogen bonding, the intermolecular forces are dominated by stacking interactions and C-H···O contacts. The thermal and calorimetric analysis was employed to probe stability of the crystal phase. The structural analysis was further supported by a computationally assisted (13)C CP/MAS NMR study, providing a complete assignment of the recorded resonances. The vibrational dynamics was explored by combining the optical (IR, Raman, TDs-THz) and inelastic neutron scattering (INS) spectroscopy techniques with the state-of-the-art solid-state density functional theory (DFT) computations. Despite the quasi-harmonic approximation assumed throughout the study, an excellent agreement between the theoretical and experimental data was achieved over the entire spectral range, allowing for a deep and possibly thorough understanding of the vibrational characteristics of the system. Particularly, the significant influence of the long-range dipole coupling on the IR spectrum has been revealed. On the basis of a wealth of information gathered, the recent implementation of a dispersion-corrected linear-response scheme has been extensively examined. PMID:25961154

  4. 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

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

    2011-01-01

    Detailed insight into the magnetic properties and mobility of the different deuteron species in jarosites (AFe3(SO4)2(OD)6, A = K, Na, D3O) is obtained from variable temperature 2H MAS NMR spectroscopy from 40 K to 300 K. Fast MAS results in high resolution spectra of these paramagnetic compounds....... The 2H NMR hyperfine shift (), measured as a function of temperature, provides to be a very sensitive probe of the local magnetic environment. Two different magnetic environments are observed: i) Fe2-OD and D3O+/ in stoichiometric regions of the sample. Here (2H) is proportional to the bulk...... susceptibility and follows a Curie-Weiss law above 150 K. ii) Fe-OD2 and D2O near Fe vacancies. The Fe near these vacancies shows strong local anti-ferromagnetic couplings even high above the Néel temperature (ca. 65 K). 2H NMR can discriminate between D2O and D3O+ ions substituted on the A site due to the...

  5. An X-ray diffraction and P-31 MAS NMR study of rare-earth phosphate glasses, (R2O3)(x)(P2O5)(1-x), x=0.175-0.263, R = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er

    Cole, Jacqueline M.; van Eck, Ernst R. H.; Mountjoy, Gavin; Anderson, Ruth; Brennan, Tessa; Bushnell-Wye, Graham; Newport, Robert J; Saunders, George A.

    2001-01-01

    An X-ray diffraction and P-31 MAS NMR study of rare-earth phosphate glasses of composition, (R2O3)(x)P2O5)(1-x), where x = 0.175-0.263 and R = La-Er (except for Pm), is presented. The structures of these materials were investigated as a function of (a) rare-earth atomic number and (b) glass composition, The results show an increase in rare-earth coordination number from six to seven as the rare-earth ion increases in size. This effect is most evident for the rare earths, Ce, Pr and Nd, and ap...

  6. Ultra-low temperature MAS-DNP

    Lee, Daniel; Bouleau, Eric; Saint-Bonnet, Pierre; Hediger, Sabine; De Paëpe, Gaël

    2016-03-01

    Since the infancy of NMR spectroscopy, sensitivity and resolution have been the limiting factors of the technique. Regular essential developments on this front have led to the widely applicable, versatile, and powerful spectroscopy that we know today. However, the Holy Grail of ultimate sensitivity and resolution is not yet reached, and technical improvements are still ongoing. Hence, high-field dynamic nuclear polarization (DNP) making use of high-frequency, high-power microwave irradiation of electron spins has become very promising in combination with magic angle sample spinning (MAS) solid-state NMR experiments. This is because it leads to a transfer of the much larger polarization of these electron spins under suitable irradiation to surrounding nuclei, greatly increasing NMR sensitivity. Currently, this boom in MAS-DNP is mainly performed at minimum sample temperatures of about 100 K, using cold nitrogen gas to pneumatically spin and cool the sample. This Perspective deals with the desire to improve further the sensitivity and resolution by providing "ultra"-low temperatures for MAS-DNP, using cryogenic helium gas. Different designs on how this technological challenge has been overcome are described. It is shown that stable and fast spinning can be attained for sample temperatures down to 30 K using a large cryostat developed in our laboratory. Using this cryostat to cool a closed-loop of helium gas brings the additional advantage of sample spinning frequencies that can greatly surpass those achievable with nitrogen gas, due to the differing fluidic properties of these two gases. It is shown that using ultra-low temperatures for MAS-DNP results in substantial experimental sensitivity enhancements and according time-savings. Access to this temperature range is demonstrated to be both viable and highly pertinent.

  7. 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

    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.

  8. Magic-angle-spinning NMR studies of zeolite SAPO-5

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

    1988-01-01

    SAPO-5 was synthesized using triethylamine as template. Magic-angle-spinning (MAS) NMR of 1H, 27Al, 29Si and 31P was used to study the silicon incorporation into the framework and the nature of the Brønsted sites. 1H MAS NMR shows two types of bridging hydroxyl groups. 29Si MAS NMR indicates that silicon substitutes mostly for phosphorus and that there is a small amount of crystalline SiO 2 in the zeolite powder.

  9. Impact of structural differences in carcinopreventive agents indole-3-carbinol and 3,3'-diindolylmethane on biological activity. An X-ray, ¹H-¹⁴N NQDR, ¹³C CP/MAS NMR, and periodic hybrid DFT study.

    Latosińska, Jolanta Natalia; Latosińska, Magdalena; Szafrański, Marek; Seliger, Janez; Žagar, Veselko; Burchardt, Dorota V

    2015-09-18

    Three experimental techniques (1)H-(14)N NQDR, (13)C CP/MAS NMR and X-ray and Density Functional Theory (GGA/BLYP with PBC) and Hirshfeld surfaces were applied for the structure-activity oriented studies of two phyto-antioxidants and anticarcinogens: indole-3-carbinol, I3C, and 3,3'-diindolylmethane, DIM, (its bioactive metabolite). One set of (14)N NQR frequencies for DIM (2.310, 2.200 and 0.110 MHz at 295K) and I3C (2.315, 1.985 and 0.330 MHz at 160K) was recorded. The multiplicity of NQR lines recorded at RT revealed high symmetry (chemical and physical equivalence) of both methyl indazole rings of DIM. Carbonyl (13)C CSA tensor components were calculated from the (13)C CP/MAS solid state NMR spectrum of I3C recorded under fast and slow spinning. At room temperature the crystal structure of I3C is orthorhombic: space group Pca21, Z=4, a=5.78922(16), b=15.6434(7) and c=8.4405(2)Å. The I3C molecules are aggregated into ribbons stacked along [001]. The oxygen atomsare disorderedbetween the two sites of different occupancy factors. It implies that the crystal is built of about 70% trans and 30% gauche conformers, and apart from the weak OH⋯O hydrogen bonds (O⋯O=3.106Å) the formation of alternative O'H⋯O bonds (O'⋯O=2.785Å) is possible within the 1D ribbons. The adjacent ribbons are further stabilised by O'H⋯O bonds (O'⋯O=2.951Å). The analysis of spectra and intermolecular interactions pattern by experimental techniques was supported by solid (periodic) DFT calculations. The knowledge of the topology and competition of the interactions in crystalline state shed some light on the preferred conformations of CH2OH in I3C and steric hindrance of methyl indole rings in DIM. A comparison of the local environment in gas phase and solid permitted drawing some conclusions on the nature of the interactions required for effective processes of recognition and binding of a given anticarcinogen to the protein or nucleic acid. PMID:26066413

  10. E/Z MAS demonstration

    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

  11. Practical enrichment technique for 33S (34S)

    The successful preparation of a macroscopic sample of enriched 33S by laser-induced molecular dissociation is reported. Approach was to induce isotopically selective dissociation of SF6 with CO2-laser pulses and to separate the remaining SF6 from the sulfur-containing reaction products by cryogenic distillation. A 200 Hz, 0.75 J/pulse laser was used for photolysis of low-pressure (less than 1 torr) gas mixtures. The mixture of SF6 and scavenger recirculated continuously throughout the irradiation chamber where the laser pulses selectively dissociated 32SF6 to give the final products: SF4 or SOF2. The unreacted SF6 was enriched in the heavier isotopes: 33S, 34S, and 36S. A 1.3-g sample of SF6 was collected with a 33S enrichment factor of 1.96 and a 34S enrichment factor of 2.25. A similar size sample of depleted (32S) sulfur compounds was also collected. A scavenger was necessary to ensure high yield, and moist hydrogen was found to be best for our conditions. Removal of hydrogen fluoride was also necessary to prevent severe corrosion and to maintain high isotopic selectivity. 6 figures

  12. 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

    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.

  13. UAV Robust Strategy Control Based on MAS

    Jian Han; Changhong Wang; Guoxing Yi

    2014-01-01

    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 coo...

  14. Fluid flow dynamics in MAS systems.

    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 1.3mm-rotor diameter has been analyzed for spinning rates up to 67kHz. 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 1.3mm-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 1.3-7mm 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. PMID:26073599

  15. A social-democracia do MAS boliviano

    Guilherme Simões Reis

    2013-01-01

    O partido MAS, que governa a Bolívia e é liderado pelo presidente Evo Morales, geralmente é classificado como populista ou como revolucionário. Este artigo contesta ambos os diagnósticos, e sustenta que o MAS é um partido social-democrata. Tanto em sua gênese, como em seu comportamento na oposição, como em suas políticas no governo, o MAS apresenta todas as características necessárias para ser classificado como um representante da social-democracia. Para contestar os diagnósticos predominante...

  16. Is solid-state NMR enhanced by dynamic nuclear polarization?

    Lee, Daniel; Hediger, Sabine; De Paëpe, Gaël

    2015-01-01

    The recent trend of high-field (~5-20 T), low-temperature (~100 K) ssNMR combined with dynamic nuclear polarization (DNP) under magic angle spinning (MAS) conditions is analyzed. A brief overview of the current theory of hyperpolarization for so-called MAS-DNP experiments is given, along with various reasons why the DNP-enhancement, the ratio of the NMR signal intensities obtained in the presence and absence of microwave irradiation suitable for hyperpolarization, should not be used alone to gauge the value of performing MAS-DNP experiments relative to conventional ssNMR. This is demonstrated through a dissection of the current conditions required for MAS-DNP with particular attention to resulting absolute sensitivities and spectral resolution. Consequently, sample preparation methods specifically avoiding the surplus of glass-forming solvents so as to improve the absolute sensitivity and resolution are discussed, as are samples that are intrinsically pertinent for MAS-DNP studies (high surface area, amorphous, and porous). Owing to their pertinence, examples of recent applications on these types of samples where chemically-relevant information has been obtained that would have been impossible without the sensitivity increases bestowed by MAS-DNP are also detailed. Additionally, a promising further implementation for MAS-DNP is exampled, whereby the sensitivity improvements shown for (correlation) spectroscopy of nuclei at low natural isotopic abundance, facilitate internuclear distance measurements, especially for long distances (absence of dipolar truncation). Finally, we give some speculative perspectives for MAS-DNP. PMID:25779337

  17. NMR crystallography of active pharmaceuticals ingredients for industrial applications

    Urbanová, Martina; Brus, Jiří; Kobera, Libor

    Herceg Novi : Materials Research Society, 2008. s. 165. [Annual Conference YUCOMAT 2008 /10./. 08.09.2008-12.09.2008, Herceg Novi] R&D Projects: GA MŠk 2B08021 Institutional research plan: CEZ:AV0Z40500505 Keywords : MAS NMR * atorvastatin * NMR crystallography Subject RIV: CF - Physical ; Theoretical Chemistry

  18. Experimental Conditions: SE33_S01_M02_D01 [Metabolonote[Archive

    Full Text Available SE33_S01_M02_D01 SE33 Eucommia ulmoides leaf metabolite analysis SE33_S01 Eucommia ...ulmoides Leaf SE33_S01_M02 6.7mg [MassBase ID] MDLC1_12975 SE33_MS1 LC-FT-ICR-MS ESI positive method 1 SE33_...DS1 PowerGet analysis for detection of all peaks (B3) 6|ITMS 2 SE33_AM1 PowerGet annotation A1 ...

  19. Experimental Conditions: SE33_S01_M03_D01 [Metabolonote[Archive

    Full Text Available SE33_S01_M03_D01 SE33 Eucommia ulmoides leaf metabolite analysis SE33_S01 Eucommia ...ulmoides Leaf SE33_S01_M03 6.7mg [MassBase ID] MDLC1_12976 SE33_MS1 LC-FT-ICR-MS ESI positive method 1 SE33_...DS1 PowerGet analysis for detection of all peaks (B3) 6|ITMS 2 SE33_AM1 PowerGet annotation A1 ...

  20. Isotopic 32S/33S ratio as a diagnostic of presolar grains from novae

    A. Parikh

    2014-10-01

    Full Text Available Measurements of sulphur isotopes in presolar grains can help to identify the astrophysical sites in which these grains were formed. A more precise thermonuclear rate of the 33S(p,γ34Cl reaction is required, however, to assess the diagnostic ability of sulphur isotopic ratios. We have studied the 33S(3He,d34Cl proton-transfer reaction at 25 MeV using a high-resolution quadrupole–dipole–dipole–dipole magnetic spectrograph. Deuteron spectra were measured at ten scattering angles between 10° and 55°. Twenty-four levels in 34Cl over Ex=4.6–5.9 MeV were observed, including three levels for the first time. Proton spectroscopic factors were extracted for the first time for levels above the 33S + p threshold, spanning the energy range required for calculations of the thermonuclear 33S(p,γ34Cl rate in classical nova explosions. We have determined a new 33S(p,γ34Cl rate using a Monte Carlo method and have performed new hydrodynamic nova simulations to determine the impact on nova nucleosynthesis of remaining nuclear physics uncertainties in the reaction rate. We find that these uncertainties lead to a factor of ≤5 variation in the 33S(p,γ34Cl rate over typical nova peak temperatures, and variation in the ejected nova yields of SCa isotopes by ≤20%. In particular, the predicted 32S/33S ratio is 110–130 for the nova model considered, compared to 110–440 with previous rate uncertainties. As recent type II supernova models predict ratios of 130–200, the 32S/33S ratio may be used to distinguish between grains of nova and supernova origin.

  1. Constraining nova observables: direct measurements of resonance strengths in 33S(p,\\gamma)34Cl

    Fallis, J; Bertone, P F; Bishop, S; Buchmann, L; Chen, A A; Christian, G; Clark, J A; D'Auria, J M; Davids, B; Deibel, C M; Fulton, B R; Greife, U; Guo, B; Hager, U; Herlitzius, C; Hutcheon, D A; José, J; Laird, A M; Li, E T; Li, Z H; Lian, G; Liu, W P; Martin, L; Nelson, K; Ottewell, D; Parker, P D; Reeve, S; Rojas, A; Ruiz, C; Setoodehnia, K; Sjue, S; Vockenhuber, C; Wang, Y B; Wrede, C

    2013-01-01

    The 33S(p,\\gamma)34Cl reaction is important for constraining predictions of certain isotopic abundances in oxygen-neon novae. Models currently predict as much as 150 times the solar abundance of 33S in oxygen-neon nova ejecta. This overproduction factor may, however, vary by orders of magnitude due to uncertainties in the 33S(p,\\gamma)34Cl reaction rate at nova peak temperatures. Depending on this rate, 33S could potentially be used as a diagnostic tool for classifying certain types of presolar grains. Better knowledge of the 33S(p,\\gamma)34Cl rate would also aid in interpreting nova observations over the S-Ca mass region and contribute to the firm establishment of the maximum endpoint of nova nucleosynthesis. Additionally, the total S elemental abundance which is affected by this reaction has been proposed as a thermometer to study the peak temperatures of novae. Previously, the 33S(p,\\gamma)34Cl reaction rate had only been studied directly down to resonance energies of 432 keV. However, for nova peak temper...

  2. Micromegas detector for $^{33}$S(n,$\\alpha$) cross section measurement at n_TOF

    The present proposal is a consequence of the successful tests performed in 2011 related to the Letter of Intent CERN-INTC-2010-023/I-092. The main goal of this proposal is a first (n,$\\alpha$) cross section measurement with the Micromegas detector presently running at n_TOF for monitoring purposes and fission cross section measurements. The $^{33}$S(n,$\\alpha$) cross section is of interest in astrophysics mainly due to the origin of $^{36}$S which is still an open question. $^{33}$S is also of interest in medical physics since it has been proposed as a possible/alternative cooperating target to boron neutron capture therapy. Important discrepancies between previous measurements of $^{33}$S(n,$\\alpha$) cross section and especially between the resonance parameters are found in the literature. We propose to measure the (n,$\\alpha$) cross section of the stable isotope $^{33}$S in the energy range up to 300 keV covering the astrophysical range of interest. The possibility of increasing this energy range will be st...

  3. In situ NMR analysis of fluids contained in sedimentary rock

    de Swiet TM; Tomaselli; Hurlimann; Pines

    1998-08-01

    Limitations of resolution and absorption in standard chemical spectroscopic techniques have made it difficult to study fluids in sedimentary rocks. In this paper, we show that a chemical characterization of pore fluids may be obtained in situ by magic angle spinning (MAS) nuclear magnetic resonance (NMR), which is normally used for solid samples. 1H MAS-NMR spectra of water and crude oil in Berea sandstone show sufficient chemical shift resolution for a straightforward determination of the oil/water ratio. Copyright 1998 Academic Press. PMID:9716484

  4. Compact NMR

    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.

  5. Compact NMR

    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.

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

    Hwang, Son-Jong; Bowman, Robert C., Jr.; Kim, Chul; Zan, Jason A.; Reiter, Joseph W.

    2011-01-01

    Solid state NMR is widely applied in studies of solid state chemistries for hydrogen storage reactions. Use of ^(11)B MAS NMR in studies of metal borohydrides (BH_4) is mainly focused, revisiting the issue of dodecaborane formation and observation of ^(11)B{^1H} Nuclear Overhauser Effect.

  7. Characterizing polymorphism by solid-state NMR, X-ray powder diffraction and factor analysis

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

    Göteborg : University of Göteborg, 2009. s. 111. [Euromar 2009 - Magnetic Resonance Conference. 05.07.2009-09.07.2009, Göteborg] R&D Projects: GA MŠk 2B08021 Institutional research plan: CEZ:AV0Z40500505 Keywords : MAS NMR * atorvastatin * NMR crystallography Subject RIV: CD - Macromolecular Chemistry

  8. An NMR Investigation of Phase Structure and Chain Dynamics in the Polyethylene/Montmorillonite Nano composites

    Novel exfoliated and interacted polyethylene (PE)/montmorillonite (MMT) nano composites prepared by in situ polymerization were characterized by solid-state nuclear magnetic resonance (NMR). The phase structure and molecular mobility were investigated by proton and carbon NMR under static and magic-angle spinning (MAS) conditions. The results showed that incorporation of MMT layer enhanced the polyethylene crystallinity behavior. The chain mobility of crystalline phase, interphase and amorphous phase was hindered in the nano composites. The phase structure and chain dynamics were also investigated upon changing the temperature. The orthorhombic and monoclinic phases were detected according to the 13CP/MAS NMR. Quantitative characterization of the phase structure was also conducted by 13C DP/MAS upon changing the temperature. Finally, the difference in the phase structure and chain dynamics in each phase of PE/nano composites was compared based on the NMR results when fiber filler was introduced

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

    Rabello Casali, K.; Ravizzoni Dartora, D.; Moura, M; Bertagnolli, M.; Bader, M; Haibara, A.; Alenina, N; Irigoyen, M.C.; Santos, R. 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). Statio...

  10. Nanosatellites for Earth Environmental Monitoring: The MicroMAS Project

    Blackwell, William; Allen, G; Conrad, S.; Galbraith, C.; Kingsbury, R.; Leslie, R; McKinley, P.; Osaretin, I.; W. Osborn; Reid, B.; Retherford, L.; Scarito, M.; Semisch, C.; Shield, M; Silver, M

    2012-01-01

    The Micro-sized Microwave Atmospheric Satellite (MicroMAS) is a dual-spinning 3U CubeSat equipped with a passive microwave spectrometer that observes nine channels near the 118.75-GHz oxygen absorption line. The focus of this MicroMAS mission (hereafter, MicroMAS-1) is to observe convective thunderstorms, tropical cyclones, and hurricanes from a near-equatorial orbit. The MicroMAS-1 flight unit is currently being developed by MIT Lincoln Laboratory, the MIT Space Systems Laboratory, and the M...

  11. NMR spectroscopy

    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

  12. Combined zero-quantum and spin-diffusion mixing for efficient homonuclear correlation spectroscopy under fast MAS: broadband recoupling and detection of long-range correlations

    Lu, Xingyu, E-mail: luxingyu@udel.edu; Guo, Changmiao, E-mail: cmguo@udel.edu; Hou, Guangjin, E-mail: hou@udel.edu; Polenova, Tatyana, E-mail: tpolenov@udel.edu [University of Delaware, Department of Chemistry and Biochemistry (United States)

    2015-01-15

    Fast magic angle spinning (MAS) NMR spectroscopy is emerging as an essential analytical and structural biology technique. Large resolution and sensitivity enhancements observed under fast MAS conditions enable structural and dynamics analysis of challenging systems, such as large macromolecular assemblies and isotopically dilute samples, using only a fraction of material required for conventional experiments. Homonuclear dipolar-based correlation spectroscopy constitutes a centerpiece in the MAS NMR methodological toolbox, and is used essentially in every biological and organic system for deriving resonance assignments and distance restraints information necessary for structural analysis. Under fast MAS conditions (rotation frequencies above 35–40 kHz), dipolar-based techniques that yield multi-bond correlations and non-trivial distance information are ineffective and suffer from low polarization transfer efficiency. To overcome this limitation, we have developed a family of experiments, CORD–RFDR. These experiments exploit the advantages of both zero-quantum RFDR and spin-diffusion based CORD methods, and exhibit highly efficient and broadband dipolar recoupling across the entire spectrum, for both short-range and long-range correlations. We have verified the performance of the CORD–RFDR sequences experimentally on a U-{sup 13}C,{sup 15}N-MLF tripeptide and by numerical simulations. We demonstrate applications of 2D CORD–RFDR correlation spectroscopy in dynein light chain LC8 and HIV-1 CA tubular assemblies. In the CORD–RFDR spectra of LC8 acquired at the MAS frequency of 40 kHz, many new intra- and inter-residue correlations are detected, which were not observed with conventional dipolar recoupling sequences. At a moderate MAS frequency of 14 kHz, the CORD–RFDR experiment exhibits excellent performance as well, as demonstrated in the HIV-1 CA tubular assemblies. Taken together, the results indicate that CORD–RFDR experiment is beneficial in a

  13. Solid state NMR study of cumbaru flour

    The polysaccharide obtained by seed of Dipteryx alata Vog, has been characterised by 13C solid state, using the basic routine techniques, like MAS and CPMAS and by the proton spin-lattice relaxation time in the rotating frame parameter (T1Hρ). 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 13C NMR spectrum of the polysaccharide was investigated to know if it has some crystallinity. The MAS 13C 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 13C decays, which give us more information about sample heterogeneity. The T1HρHr 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)

  14. 二维双量子魔角旋转核磁共振技术在功能材料研究中的应用%Application of Two-dimensional Double Quantum Magic Angle Spinning NMR to Solid Functional Materials

    喻志武; 郑安民; 王强; 邓风

    2011-01-01

    简要介绍了二维双量子魔角旋转核磁共振(DQ-MAS NMR)新技术的基本原理,详细综述了1H,19F,29Si,31P和27 Al DQ-MAS NMR技术在各种固体功能材料中的应用,并展望了该技术的应用前景.%Solid-state NMR spectroscopy has been developed into a powerful tool for obtaining detailed information about the structure, ordering, and dynamics in various kinds of inorganic organic, and biological materials. Two-dimensional double quantum magic angle spinning(DQ-MAS) NMR experiment is a useful method for probing spatial proximities or interactions between nuclei in various solid materials. During the past decade, the DQ-MAS NMR technique has been successfully applied not only to spin I = 1/2 nuclei, such as 1H, 19F, 29Si' 31p, but also to quadrupolar nuclei system, such as 27Al, 11B and 23Na. In this paper, we briefly introduce the principle of two-dimensional DQ-MAS NMR, and review the recent applications of DQ-MAS NMR technique(including 1H, 19F, 29Si, 31p and 27Al DQ-MAS NMR) to various solid functional materials. In addition, a perspective for the future of DQ-MAS NMR is also given.

  15. The stoichiometry of synthetic alunite as a function of hydrothermal aging investigated by solid-state NMR spectroscopy, powder X-ray diffraction and infrared spectroscopy

    Grube, Elisabeth; Nielsen, Ulla Gro

    2015-01-01

    angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. The 1H MAS NMR spectra recorded at high magnetic field (21.1 T, 900 MHz) allowed for a clear separation of the different proton environments and for quantitative determination of the aluminum vacancy concentration as a function of time....... The concentration of structural defects determined from, i.e., aluminum vacancies was reduced from 4 to 1 %, as the reaction time was extended from one to 31 days based on 1H MAS NMR. This was further supported by an increase of the unit cell parameter c, which is indicative of the relative...... concentration of potassium defects present, from 17.261(1) to 17.324(5) Å. Solid-state 27Al MAS NMR revealed a decrease in the defect concentration as a function of time and showed the presence of 7-10 % impurities in the samples....

  16. Structural analysis of a signal peptide inside the ribosome tunnel by DNP MAS NMR.

    Lange, Sascha; Franks, W Trent; Rajagopalan, Nandhakishore; Döring, Kristina; Geiger, Michel A; Linden, Arne; van Rossum, Barth-Jan; Kramer, Günter; Bukau, Bernd; Oschkinat, Hartmut

    2016-08-01

    Proteins are synthesized in cells by ribosomes and, in parallel, prepared for folding or targeting. While ribosomal protein synthesis is progressing, the nascent chain exposes amino-terminal signal sequences or transmembrane domains that mediate interactions with specific interaction partners, such as the signal recognition particle (SRP), the SecA-adenosine triphosphatase, or the trigger factor. These binding events can set the course for folding in the cytoplasm and translocation across or insertion into membranes. A distinction of the respective pathways depends largely on the hydrophobicity of the recognition sequence. Hydrophobic transmembrane domains stabilize SRP binding, whereas less hydrophobic signal sequences, typical for periplasmic and outer membrane proteins, stimulate SecA binding and disfavor SRP interactions. In this context, the formation of helical structures of signal peptides within the ribosome was considered to be an important factor. We applied dynamic nuclear polarization magic-angle spinning nuclear magnetic resonance to investigate the conformational states of the disulfide oxidoreductase A (DsbA) signal peptide stalled within the exit tunnel of the ribosome. Our results suggest that the nascent chain comprising the DsbA signal sequence adopts an extended structure in the ribosome with only minor populations of helical structure. PMID:27551685

  17. Aspects of Wood Adhesion: Applications of 13C CP/MAS NMR and Fracture Testing

    Schmidt, Robert G

    1998-01-01

    Phenol Formaldehyde (PF) and polymeric isocyanate (pMDI) are the two main types of adhesives used in the production of structural wood-based composites. Much is unknown about various aspects of adhesion between these two types of resins and wood. The present research describes the development of techniques which will permit an enhanced understanding of 1.) the extent of cure of PF within a wood based composite, 2.) the scale of molecular level interactions between PF and pMDI and wood, 3.) ...

  18. Quantitative analysis of backbone motion in proteins using MAS solid-state NMR spectroscopy

    Chevelkov, Veniamin; Fink, Uwe; Reif, Bernd [Leibniz-Forschungsinstitut fuer Molekulare Pharmakologie (FMP) (Germany)], E-mail: reif@fmp-berlin.de

    2009-09-15

    We present a comprehensive analysis of protein dynamics for a micro-crystallin protein in the solid-state. Experimental data include {sup 15}N T{sub 1} relaxation times measured at two different magnetic fields as well as {sup 1}H-{sup 15}N dipole, {sup 15}N CSA cross correlated relaxation rates which are sensitive to the spectral density function J(0) and are thus a measure of T{sub 2} in the solid-state. In addition, global order parameters are included from a {sup 1}H,{sup 15}N dipolar recoupling experiment. The data are analyzed within the framework of the extended model-free Clore-Lipari-Szabo theory. We find slow motional correlation times in the range of 5 and 150 ns. Assuming a wobbling in a cone motion, the amplitude of motion of the respective amide moiety is on the order of 10 deg. for the half-opening angle of the cone in most of the cases. The experiments are demonstrated using a perdeuterated sample of the chicken {alpha}-spectrin SH3 domain.

  19. A Construction Way of MAS Based on Organization Theory

    GAO Bo; FEI Qi; CHEN Xue-guang

    2002-01-01

    With emphasizing that the integration of autonomy and coordination is the basis for constructing multi-agent systems (MAS), we analyze the organizational characters inherent with MAS and point out that it's a natural and essential way to construct MAS based on organization theory. We consider that the emphasis of the theory is the process of system analyzing. Then we present an analysis frame to expound the process, which includes the process of organization definition, the process of role definition, the process of organizational structure definition and the process of interaction protocol definition. Lastly, we discuss some issues associated with the processes of system design and implementation.

  20. Solid state NMR study calcium phosphate ceramics

    High-resolution 31P and 1H NMR spectra at 40 and 121 MHz 31P and 300 MHz 1H of synthetic and biological samples of calcium phosphates have been obtained by magic angle spinning (MAS) at spinning speeds up to 6.5 kHz, and high power proton decoupling. The samples include crystalline hydroxyapatite, a deficient hydroxyapatite characterized by a Ca/P atomic ratio of 1.5, a poorly crystallized hydroxyapatite, monetite, brushite, octacalcium phosphate, β-tricalcium phosphate and rabbit femoral bone. The interactions between nuclei in unlike structures and the mobility of acid protons are discussed. (author). 11 refs.; 2 figs.; 1 tab

  1. Solid-state NMR enhanced by dynamic nuclear polarization as a novel tool for ribosome structural biology

    Gelis, Ioannis; Vitzthum, Veronika; Dhimole, Neha; Caporini, Marc A.; Schedlbauer, Andreas; Carnevale, Diego; Connell, Sean R.; Fucini, Paola; Bodenhausen, Geoffrey

    2013-01-01

    The impact of Nuclear Magnetic Resonance (NMR) on studies of large macromolecular complexes hinges on improvements in sensitivity and resolution. Dynamic nuclear polarization (DNP) in the solid state can offer improved sensitivity, provided sample preparation is optimized to preserve spectral resolution. For a few nanomoles of intact ribosomes and an 800 kDa ribosomal complex we demonstrate that the combination of DNP and magic-angle spinning NMR (MAS-NMR) allows one to overcome current sensi...

  2. Evaluating Interaction of MAS Providing Context-Aware Services

    Sánchez-Pi, Nayat; Griol, David; Carbó, Javier; José M. Molina

    2011-01-01

    Much effort has been spent on suggesting and implementing new architectures of MAS to specific domains. Often each new architecture is not even compared to any existing architectures in order to evaluate their potential benefits. The evaluation of Multi-Agent Systems (MAS) is a complex problem and it does not have a single form. The present work follows the research line of considering the agent interaction as the main evaluation criteria, the most important characteristic of any complex soft...

  3. Solid-State NMR Examination of Alteration Layers on a Nuclear Waste Glasses

    Murphy, Kelly A. [Penn State Univ., State College, PA (United States). Dept. of Chemistry; Washton, Nancy M. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States). Environmental Molecular Science Lab.; Ryan, Joseph V. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Pantano, Carlo G. [Penn State Univ., State College, PA (United States). Dept. of Materials Science and Engineering; Mueller, Karl T. [Penn State Univ., State College, PA (United States). Dept. of Chemistry; Pacific Northwest National Laboratory (PNNL), Richland, WA (United States). Environmental Molecular Science Lab.

    2013-06-01

    Solid-state NMR is a powerful tool for probing the role and significance of alteration layers in determining the kinetics for the corrosion of nuclear waste glass. NMR methods are used to probe the chemical structure of the alteration layers to elucidate information about their chemical complexity, leading to increased insight into the mechanism of altered layer formation. Two glass compositions were examined in this study: a glass preliminarily designed for nuclear waste immobilization (called AFCI) and a simplified version of this AFCI glass (which we call SA1R). Powdered glasses with controlled and known particles sizes were corroded at 90 °C for periods of one and five months with a surface-area to solution-volume ratio of 100,000 m-1. 1H-29Si CP-CPMG MAS NMR, 1H-27Al CP-MAS NMR, 1H-11B CP-MAS NMR, and 1H-23Na CP-MAS NMR experiments provide isolated structural information about the alteration layers, which differ in structure from that of the pristine glass. Both glasses studied here develop alteration layers composed primarily of [IV]Si species. Aluminum is also retained in the alteration layers, perhaps facilitated by the observed increase in coordination from [IV]Al to [VI]Al, which correlates with a loss of charge balancing cations. 1H-11B CP-MAS NMR observations indicated a retention of boron in hydrated glass layers, which has not been characterized by previous work. For the AFCI glass, secondary phase formation begins during the corrosion times considered here, and these neophases are detected within the alteration layers. We identify precursor phases as crystalline sodium metasilicates. An important finding is that layer thickness depends on the length of the initial alteration stages and varies only with respect to silicon species during the residual rate regime.

  4. Solid-State NMR Examination of Alteration Layers on a Nuclear Waste Glasses

    Solid-state NMR is a powerful tool for probing the role and significance of alteration layers in determining the kinetics for the corrosion of nuclear waste glass. NMR methods are used to probe the chemical structure of the alteration layers to elucidate information about their chemical complexity, leading to increased insight into the mechanism of altered layer formation. Two glass compositions were examined in this study: a glass preliminarily designed for nuclear waste immobilization (called AFCI) and a simplified version of this AFCI glass (which we call SA1R). Powdered glasses with controlled and known particles sizes were corroded at 90 °C for periods of one and five months with a surface-area to solution-volume ratio of 100,000 m-1. 1H-29Si CP-CPMG MAS NMR, 1H-27Al CP-MAS NMR, 1H-11B CP-MAS NMR, and 1H-23Na CP-MAS NMR experiments provide isolated structural information about the alteration layers, which differ in structure from that of the pristine glass. Both glasses studied here develop alteration layers composed primarily of [IV]Si species. Aluminum is also retained in the alteration layers, perhaps facilitated by the observed increase in coordination from [IV]Al to [VI]Al, which correlates with a loss of charge balancing cations. 1H-11B CP-MAS NMR observations indicated a retention of boron in hydrated glass layers, which has not been characterized by previous work. For the AFCI glass, secondary phase formation begins during the corrosion times considered here, and these neophases are detected within the alteration layers. We identify precursor phases as crystalline sodium metasilicates. An important finding is that layer thickness depends on the length of the initial alteration stages and varies only with respect to silicon species during the residual rate regime

  5. Crystal structure based design of signal enhancement schemes for solid-state NMR of insensitive half-integer quadrupolar nuclei.

    O'Dell, Luke A; Ratcliffe, Christopher I

    2011-02-10

    A combination of density functional and optimal control theory has been used to generate amplitude- and phase-modulated excitation pulses tailored specifically for the (33)S nuclei in taurine, based on one of several reported crystal structures. The pulses resulted in significant signal enhancement (stemming from population transfer from the satellite transitions) without the need for any experimental optimization. This allowed an accurate determination of the (33)S NMR interaction parameters at natural abundance and at a moderate magnetic field strength (11.7 T). The (33)S NMR parameters, along with those measured from (14)N using frequency-swept pulses, were then used to assess the accuracy of various proposed crystal structures. PMID:21174418

  6. Unearthing Foundations of a Cosmic Cathedral: Searching the Stars for M33's Halo

    Cockcroft, Robert; Harris, William E; Ibata, Rodrigo; Irwin, Mike J; Ferguson, Annette M N; Fardal, Mark A; Babul, Arif; Chapman, Scott C; Lewis, Geraint F; Martin, Nicolas F; Puzia, Thomas H

    2012-01-01

    We use data from the Pan-Andromeda Archaeological Survey (PAndAS) to search for evidence of an extended halo component belonging to M33 (the Triangulum Galaxy). We identify a population of red giant branch (RGB) stars at large radii from M33's disk whose connection to the recently discovered extended "disk substructure" is ambiguous, and which may represent a "bona-fide" halo component. After first correcting for contamination from the Milky Way foreground population and misidentified background galaxies, we average the radial density of RGB candidate stars over circular annuli centered on the galaxy and away from the disk substructure. We find evidence of a low-luminosity, centrally concentrated component that is everywhere in our data fainter than mu_V ~ 33 mag arcsec^(-2). The scale length of this feature is not well constrained by our data, but it appears to be of order r_exp ~ 20 kpc; there is weak evidence to suggest it is not azimuthally symmetric. Inspection of the overall CMD for this region that spe...

  7. 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

    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 27Al and 31P 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 11B MAS, 29Si MAS and in situ 29Si{11B} REAPDOR NMR spectroscopy. (authors)

  8. NMR studies of metabolism

    In this paper, the authors present applications of NMR to the study of different aspects of metabolism. The authors begin with a brief outline of localization methods that are commonly used to obtain in vivo NMR spectra. The authors then describe in more detail metabolic information recently obtained by NMR of perfused organs, intact animals, and humans. Previous reviews have already covered the applications of NMR to the study of metabolism in microorganisms, isolated or cultivated cells, and tumors. NMR spectroscopy of the brain, and human in vivo NMR spectroscopy have also been reviewed

  9. High resolution nuclear magnetic resonance spectroscopy (NMR) studies on meat components: potentialities and prospects

    Antonio Sacco; Gino Vonghia; Francesco Giannico; Daniela Sacco; Vincenzo di Martino; Anna Caputi Jambrenghi; Maria Antonietta Brescia

    2010-01-01

    In recent years, increasing application of nuclear magnetic resonance (NMR) spectroscopy in the study of the agricultur-  al food products has been remarked, thanks to the advantages of this technique over other conventional analytical tech-  niques. This preliminary work presents, for the first time, the application of an innovative NMR technique, the  proton  high resolution magic angle spinning (1H HR-MAS), for studying meat features. It stresses that this method makes ...

  10. Dynamic nuclear polarization enhanced NMR at 187 GHz/284 MHz using an extended interaction Klystron amplifier

    Watts, A; Kemp, T; Dannatt, HRW; Barrow, NS; Brown, SP; Newton, ME; Dupree, R.

    2016-01-01

    A Dynamic Nuclear Polarisation (DNP) enhanced solid-state Magic Angle Spinning (MAS) NMR spectrometer which uses a 187 GHz (corresponding to 1H 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 i...

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

    Santos, Maiara S.; Edenir R. Pereira-Filho; Antonio G. Ferreira; Elisangela F. Boffo; 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, ¹H HR-MAS NMR and ¹H NMR in solution, combined with chemo...

  12. An MAS-Based ETL Approach for Complex Data

    Boussaïd, Omar; Darmont, Jérôme

    2008-01-01

    In a data warehousing process, the phase of data integration is crucial. Many methods for data integration have been published in the literature. However, with the development of the Internet, the availability of various types of data (images, texts, sounds, videos, databases...) has increased, and structuring such data is a difficult task. We name these data, which may be structured or unstructured, "complex data". In this paper, we propose a new approach for complex data integration, based on a Multi-Agent System (MAS), in association to a data warehousing approach. Our objective is to take advantage of the MAS to perform the integration phase for complex data. We indeed consider the different tasks of the data integration process as services offered by agents. To validate this approach, we have actually developed an MAS for complex data integration.

  13. NMR analysis of biodiesel

    Biodiesel is usually analyzed by the various methods called for in standards such as ASTM D6751 and EN 14214. Nuclear magnetic resonance (NMR) is not one of these methods. However, NMR, with 1H-NMR commonly applied, can be useful in a variety of applications related to biodiesel. These include monit...

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

    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

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

    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

  16. Project MAS 1984-1985. OEA Evaluation Report.

    New York City Board of Education, Brooklyn. Office of Educational Assessment.

    This multi-site instructional program (Project MAS) provides instruction in English as a second language and native language arts, as well as bilingual instruction in mathematics and science to approximately 400 Spanish-speaking schools. It serves third through eighth graders at four sites in the Bronx. Its instructional and non-instructional…

  17. Study of the 30P(α,p)33S reaction using a gas-filled magnetic spectrograph

    We have developed a technique using a gas-filled magnetic spectrograph which enables us to study (α,p) transfer reactions of astrophysical interest in inverse kinematics and by means of the time-inverse reactions. We present preliminary experimental results of the reaction 30P(α,p)33S which confirm that the technique permits the study of these kinds of transfer reactions.

  18. Fluorine dynamics in BaF2 superionic conductors investigated by NMR

    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...

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

    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. (author)

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

    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)

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

    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.

  2. High Resolution Magic Angle Spinning 1H-NMR Metabolic Profiling of Nanoliter Biological Tissues at High Magnetic Field

    Feng, Ju; Hu, Jian Z.; Burton, Sarah D.; Hoyt, David W.

    2013-03-05

    It is demonstrated that a high resolution magic angle spinning 1H-NMR spectrum of biological tissue samples with volumes as small as 150 nanoliters, or 0.15 mg in weight, can be acquired in a few minutes at 21.1 T magnetic field using a commercial 1.6 mm fast-MAS probe with minor modification of the MAS rotor. The strategies of sealing the samples inside the MAS rotor to avoid fluid leakage as well as the ways of optimizing the signal to noise are discussed.

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

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

    2006-01-01

    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...... have been investigated in detail by 29Si and 27Al MAS NMR where the combination of the results for these spin-nuclei provides important information on the degree of Al-incorporation in the C-S-H structure and of the average chain lengths of tetrahedral SiO4 and AlO4 units. This presentation will...

  4. Probing structure and dynamics of protein assemblies by magic angle spinning NMR spectroscopy.

    Yan, Si; Suiter, Christopher L; Hou, Guangjin; Zhang, Huilan; Polenova, Tatyana

    2013-09-17

    In living organisms, biological molecules often organize into multicomponent complexes. Such assemblies consist of various proteins and carry out essential functions, ranging from cell division, transport, and energy transduction to catalysis, signaling, and viral infectivity. To understand the biological functions of these assemblies, in both healthy and disease states, researchers need to study their three-dimensional architecture and molecular dynamics. To date, the large size, the lack of inherent long-range order, and insolubility have made atomic resolution studies of many protein assemblies challenging or impractical using traditional structural biology methods such as X-ray diffraction and solution NMR spectroscopy. In the past 10 years, we have focused our work on the development and application of magic angle spinning solid-state NMR (MAS NMR) methods to characterize large protein assemblies at atomic-level resolution. In this Account, we discuss the rapid progress in the field of MAS NMR spectroscopy, citing work from our laboratory and others on methodological developments that have facilitated the in-depth analysis of biologically important protein assemblies. We emphasize techniques that yield enhanced sensitivity and resolution, such as fast MAS (spinning frequencies of 40 kHz and above) and nonuniform sampling protocols for data acquisition and processing. We also discuss the experiments for gaining distance restraints and for recoupling anisotropic tensorial interactions under fast MAS conditions. We give an overview of sample preparation approaches when working with protein assemblies. Following the overview of contemporary MAS NMR methods, we present case studies into the structure and dynamics of two classes of biological systems under investigation in our laboratory. We will first turn our attention to cytoskeletal microtubule motor proteins including mammalian dynactin and dynein light chain 8. We will then discuss protein assemblies from the

  5. Study of the ferroelastic phase transition in the tetraethylammonium compound [N(C2H54]2ZnBr4 by magic-angle spinning and static NMR

    Ae Ran Lim

    2016-03-01

    Full Text Available The ferroelastic phase transition of tetraethylammonium compound [N(C2H54]2ZnBr4 at the phase transition temperature (TC = 283 K was characterized by magic-angle spinning (MAS and static nuclear magnetic resonance (NMR, and confirmed by optical polarizing spectroscopy. The structural geometry near TC was studied in terms of the chemical shifts and the spin-lattice relaxation times T1ρ in the rotating frame for 1H MAS NMR and 13C cross-polarization (CP/MAS NMR. The two inequivalent ethyl groups were distinguishable in the 13C NMR spectrum, and the T1ρ results indicate that they undergo tumbling motion above TC in a coupled manner. From the 14N NMR results, the two nitrogen nuclei in the N(C2H54+ ions were distinguishable above TC, and the splitting in the spectra below TC was related to the ferroelastic domains with different orientations.

  6. NMR at 900 MHz

    2002-01-01

    @@ An important factor in the development of solutionstate NMR has always been th e ability to produce stable and homogeneous magnetic fields. As higher and higher field strengths are reached the pressure is growing on manufacturers to produce NMR systems with greatly improved spectral resolution and signal to noise ratio. The introduction of the Varian 900 MHz INOVA system in August 2000 featuring Oxford Instruments 21.1 T magnet represents the latest pioneering development in NMR technology.

  7. Solid-state NMR studies of bacteriorhodopsin and the purple membrane

    Mason, A J

    2001-01-01

    proteins. This technique may prove particularly useful when studying large proteins that are difficult to orient where the MAS lineshapes will remain relatively unaffected in comparison with current static NMR methods. Finally the MAOSS method was extended to the study of the lipid components of the purple membrane and the feasibility of determining structural constraints from phospholipid headgroups was assessed. The potential of using sup 3 sup 1 P NMR to observe qualitative protein-lipid interactions in both the purple membrane and reconstituted membranes containing bovine rhodopsin was also demonstrated. Following the demonstration of a new MAS NMR method for resolving orientational constraints in uni-axially oriented biological membranes (Glaubitz and Watts, 1998), experiments were performed to realise the potential of the new method on large, oriented membrane proteins. Using bacteriorhodopsin in the purple membrane as a paradigm for large membrane proteins, the protein was specifically labelled with de...

  8. 10B and 11B high-resolution NMR studies on boron-doped diamond

    Murakami, M.; Shimizu, T.; Tansho, M.; Takano, Y.; Ishii, S.; Ekimov, E. A.; Sidorov, V. A.; Takegoshi, K.

    2010-12-01

    11B magic-angle spinning (MAS) NMR experiments are applied to B-doped diamond samples prepared by high-pressure and high-temperature methods. From the spectrum, we show that there are at least four boron signal components and the one at 28.5 ppm is ascribed to the substitutional boron in the diamond structure providing the carriers responsible for conductivity. We further apply two-dimensional (2D) NMR to examine 1H dipolar broadening and 11B-11B boron spin diffusion, and candidates purported so far for the excess boron, that is, a boron + hydrogen complex and -B-B- and/or -B-C-B- clusters are negated. Furthermore, we show that 10B MAS NMR is useful to selectively observe the substitutional boron in the diamond structure appearing at 28.5 ppm, whose quadrupolar coupling is much smaller than that of the excess boron at 65.5 ppm.

  9. DynamicWorkflow in Grid-MAS Integration Context

    Salle, Paola; Duvert, Frédéric; Hérin, Danièle; Stefano A. CERRI

    2007-01-01

    This paper addresses the architectural foundations of dynamic workflows in distributed multi-agent systems (MAS) integrated in Grid context. The purpose is to design an architecture at the same time taking into consideration tasks dependencies among agents, adaptation with respect to historic lessons learnt from past behaviour (memory) and the autonomous decisions when an unpredicted event occurs. In order to do this, given one ontology, called AGIO, which describes Agent-Grid Integration, we...

  10. Commercial facility site selection simulating based on MAS

    Chao, Yi; Li, Qingquan; Zheng, Guizhou

    2008-10-01

    The location of commercial facility decides the benefit of the operator to a large degree. Existing location methods can express the static relationships between site selection result and location factors, but there still are some limites when express the dynamic and uncertain relationship between them. Hence, a dynamic, stochastic and forecastable location model should be built which can introduce the customer's behavior into the model and combine the macro pattern and micro spatial interaction. So the authors proposes Geosim-LM based on MAS. Geosim-LM has 3 kinds of agents, CustAgent, SiteAgent and GovAgent. They represent the customers, commercial fercilities and government. The land type, land price and traffic are the model environment. Then Geosim-LM is applied in the bank branches site evaluation and selection in Liwan district, Guangzhou. In existing bank branches site evaluation, there are 70% consistent in score grade between result of Geosim-LM after 200 round runing and actual rebust location. It proves the model is reliable and feasible. The conclusions can be get from the paper. MAS have advantages in location choice than existed methods. The result of Geosim-LM running can powerfully proves that building location model based on MAS is feasible.

  11. Lectures on pulsed NMR

    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

  12. Lectures on pulsed NMR

    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

  13. MAS及其相关概念%MAS and Correlation Conceptions

    程显毅; 董红斌

    2000-01-01

    The researching of MAS originates from distributed artificial intelligence ,because new theory framework is provided for solving some problems in complex and distributed environment ,MAS is valued increasingly by computer ,automatic control and management science.

  14. Formalization of the Abstract Architecture of MAS Based on FIPA Specification

    Zheng Liwei(郑丽伟); Yu Xueli; Feng Xiufang

    2003-01-01

    The FIPA specification of MAS (multi-agent system)is accepted by most of the applications of MAS in the world, and has been used in many projects. This paper draws an abstract architecture from the FIPA based MAS, and gives formalization about it.

  15. Characterization of polymers by nuclear magnetic resonance (NMR)

    After having recalled some generalities which are necessary for the obtention of a spectrum and the method to be chosen, the author considers the use of the hydrogen 1 and carbon 13 high resolution nuclear magnetic resonance (in liquid and solid phase) on some examples in the field of polymers. In the case of the polymers in solution, this technology seems to be limited to liquid or soluble polymers and to insoluble polymers which are inflatable in some solvents. The other polymers (infusible and non-inflatable) require the use of the CP-MAS solid phase NMR (cross polarization magic angle spinning nuclear magnetic resonance). For liquids, the NMR allows to better know the microstructure of these compounds and to better understand the reaction mechanisms (in the case of poly-condensation, polymerization, degradation..) which can control the polymerization. The CP-MAS solid phase NMR is a particularly interesting method for the determination of insoluble three-dimensional polymers structures and for the study of the conformations and configurations of the chain carbonated skeleton. (O.M.). 46 refs., 18 figs

  16. O-17 NMR studies of some silicate crystals and glasses

    Yildirim, E K

    2000-01-01

    structure. Therefore some of the Sn has to be in three coordinated to oxygen for charge balancing. The sup 1 sup 7 O MAS NMR spectra of a partially crystallised sample showed three distinct sites which are assigned as Sn-O-Sn, Si-O-Sn, and Si-O-Si on the basis of their chemical shift. The C sub Q values obtained from the simulations of these peaks supports this assignment. The sup 2 sup 9 Si MAS NMR of the same sample showed two crystalline and a glassy peaks which are fitted to two crystalline and two glassy sites. The possible composition of this sample was calculated and found to be SiSn sub 8 O sub 1 sub 0. Crystalline and glassy silicates were investigated by means of sup 1 sup 7 O NMR. The dependence of the measured efg on the Si-O-AI bond angle was investigated in some crystalline aluminosilicate sodalites and kalsilite. The results show that C sub Q increases with increasing bond angle while eta decreases with increasing bond angle and they both follow a similar function to that found for the Si-O-Si ...

  17. Solid-state NMR in the analysis of drugs and naturally occurring materials.

    Paradowska, Katarzyna; Wawer, Iwona

    2014-05-01

    This article presents some of the solid-state NMR (SSNMR) techniques used in the pharmaceutical and biomedical research. Solid-state magic angle spinning (MAS) NMR provides structural information on powder amorphous solids for which single-crystal diffraction structures cannot be obtained. NMR is non-destructive; the powder sample may be used for further studies. Quantitative results can be obtained, although solid-state NMR spectra are not normally quantitative. As compared with other techniques, MAS NMR is insensitive and requires a significant amount of the powder sample (2-100mg) to fill the 1.3-7 mm ZrO2 rotor. This is its main drawback, since natural compounds isolated from plants, microorganisms or cell cultures are difficult to obtain in quantities higher than a few milligrams. Multinuclear MAS NMR routinely uses (1)H and (13)C nuclei, less frequently (15)N, (19)F, (31)P, (77)Se, (29)Si, (43)Ca or (23)Na. The article focuses on the pharmaceutical applications of SSNMR, the studies were aimed to control over manufacturing processes (e.g. crystallization and milling) investigation of chemical and physical stability of solid forms both as pure drug and in a formulated product. SSNMR is used in combination with some other analytical methods (DSC, XRD, FT-IR) and theoretical calculations of NMR parameters. Biologically active compounds, such as amino acids and small peptides, steroids and flavonoids were studied by SSNMR methods (part 4) providing valuable structural information. The SSNMR experiments performed on biopolymers and large natural products like proteins, cellulose and lipid layers are commented upon briefly in part 5. PMID:24173236

  18. Optimization of MAS and MODIS Polar ocean cloud mask

    Memmen, Sean P.

    2000-01-01

    With the reduction of funding for sea ice reconnaissance flights, the National/Naval Ice Center needs to capitalize on the improvements in satellite technology. Imaging sensors such as AVHRR, DMSP/OLS, SSM/I and RADARSAT have been used to detect the presence of sea ice, but with the exception of SSM/I and RADARSAT, clouds are a major obstacle to viewing the surface. With NASA's development of the Moderate-resolution Imaging Spectroradiometer (MODIS) and MODIS Airborne Simulator (MAS), there i...

  19. MAS-SCM for Auto Sector-The Framework

    Ritu Sindhu

    2011-07-01

    Full Text Available The purpose of this study is to describe in detail the development status of the innovative Multi -Agent based supply chain management (MAS-SCMAS for auto sector. This study was undertaken in view of the significance of improvement in efficiency of automobile sector and the development of a good multi-agent system framework to achieve that. The factors affecting the efficiency or OEE of the industry and the efficiency properties were identified. It was clearly revealed that the available model do not fulfill the needs in the supply chain management of automobile industry and there is a scope for evolving new model resulting in better efficiency.

  20. The MAS Six Years in Power in Bolivia

    2012-01-01

    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: Haymark...

  1. Carbon-13 solid state NMR studies in the aromatization of residual coals from hydropyrolised cellulose

    Pure cellulose was pyrolyzed is a fixed-bed reactor under hydrogen pressure (hydropyrolysis). Residual chars were collected and analysed by solid state nmr 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)

  2. Asynchronous through-bond homonuclear isotropic mixing: application to carbon–carbon transfer in perdeuterated proteins under MAS

    Kulminskaya, Natalia; Vasa, Suresh Kumar; Giller, Karin; Becker, Stefan; Linser, Rasmus, E-mail: rali@nmr.mpibpc.mpg.de [Max Planck Institute for Biophysical Chemistry, Department of NMR-based Structural Biology (Germany)

    2015-11-15

    Multiple-bond carbon–carbon homonuclear mixing is a hurdle in extensively deuterated proteins and under fast MAS due to the absence of an effective proton dipolar-coupling network. Such conditions are now commonly employed in solid-state NMR spectroscopy. Here, we introduce an isotropic homonuclear {sup 13}C–{sup 13}C through-bond mixing sequence, MOCCA, for the solid state. Even though applied under MAS, this scheme performs without rotor synchronization and thus does not pose the usual hurdles in terms of power dissipation for fast spinning. We compare its performance with existing homonuclear {sup 13}C–{sup 13}C mixing schemes using a perdeuterated and partially proton-backexchanged protein. Based on the analysis of side chain carbon–carbon correlations, we show that particularly MOCCA with standard 180-degree pulses and delays leading to non-rotor-synchronized spacing performs exceptionally well. This method provides high magnetization transfer efficiency for multiple-bond transfer in the aliphatic region compared with other tested mixing sequences. In addition, we show that this sequence can also be tailor-made for recoupling within a selected spectral region using band-selective pulses.

  3. Asynchronous through-bond homonuclear isotropic mixing: application to carbon–carbon transfer in perdeuterated proteins under MAS

    Multiple-bond carbon–carbon homonuclear mixing is a hurdle in extensively deuterated proteins and under fast MAS due to the absence of an effective proton dipolar-coupling network. Such conditions are now commonly employed in solid-state NMR spectroscopy. Here, we introduce an isotropic homonuclear 13C–13C through-bond mixing sequence, MOCCA, for the solid state. Even though applied under MAS, this scheme performs without rotor synchronization and thus does not pose the usual hurdles in terms of power dissipation for fast spinning. We compare its performance with existing homonuclear 13C–13C mixing schemes using a perdeuterated and partially proton-backexchanged protein. Based on the analysis of side chain carbon–carbon correlations, we show that particularly MOCCA with standard 180-degree pulses and delays leading to non-rotor-synchronized spacing performs exceptionally well. This method provides high magnetization transfer efficiency for multiple-bond transfer in the aliphatic region compared with other tested mixing sequences. In addition, we show that this sequence can also be tailor-made for recoupling within a selected spectral region using band-selective pulses

  4. μHigh resolution-magic-angle spinning NMR spectroscopy for metabolic phenotyping of Caenorhabditis elegans.

    Wong, Alan; Li, Xiaonan; Molin, Laurent; Solari, Florence; Elena-Herrmann, Bénédicte; Sakellariou, Dimitris

    2014-06-17

    Analysis of model organisms, such as the submillimeter-size Caenorhabditis elegans, plays a central role in understanding biological functions across species and in characterizing phenotypes associated with genetic mutations. In recent years, metabolic phenotyping studies of C. elegans based on (1)H high-resolution magic-angle spinning (HR-MAS) nuclear magnetic resonance (NMR) spectroscopy have relied on the observation of large populations of nematodes, requiring labor-intensive sample preparation that considerably limits high-throughput characterization of C. elegans. In this work, we open new platforms for metabolic phenotyping of C. elegans mutants. We determine rich metabolic profiles (31 metabolites identified) from samples of 12 individuals using a (1)H NMR microprobe featuring high-resolution magic-angle coil spinning (HR-MACS), a simple conversion of a standard HR-MAS probe to μHR-MAS. In addition, we characterize the metabolic variations between two different strains of C. elegans (wild-type vs slcf-1 mutant). We also acquire a NMR spectrum of a single C. elegans worm at 23.5 T. This study represents the first example of a metabolomic investigation carried out on a small number of submillimeter-size organisms, demonstrating the potential of NMR microtechnologies for metabolomics screening of small model organisms. PMID:24897622

  5. An explanation for the high stability of polycarboxythiophenes in photovoltaic devices—A solid-state NMR dipolar recoupling study

    Bierring, M.; Nielsen, J.S.; Siu, Ana;

    2008-01-01

    acid carbon atoms were measured by C-13 solid-state magic-angle-spinning (MAS) NMR using symmetry-based double-quantum (2Q) dipolar recoupling. This revealed the presence of C-13-C-13 distances of 3.85 angstrom, which correspond to the C-C distance in hydrogen-bonded carboxylic acid dimers. In spite of...

  6. Milli-Arcsecond (MAS) Imaging of the Solar Corona

    Davila, Joseph M.; Oktem, Figen S.; Kamalabadi, Farzad; O'Neill, John; Novo-Gradac, Anne-Marie; Daw, Adrian N.; Rabin, Douglas M.

    2016-05-01

    Dissipation in the solar corona is believed to occur in extremely thin current sheets of order 1-100 km. Emission from these hot but thin current sheets should be visible in coronal EUV emission lines. However, this spatial scale is far below the resolution of existing imaging instruments, so these dissipation sites have never been observed individually. Conventional optics cannot be manufactured with sufficient surface figure accuracy to obtain the required spatial resolution in the extreme-ultraviolet where these hot plasmas radiate. A photon sieve, a diffractive imaging element similar to a Fresnel zone plate, can be manufactured to provide a few milli-arcsec (MAS) resolution, with much more readily achievable tolerances than with conventional imaging technology. Prototype photon sieve elements have been fabricated and tested in the laboratory. A full-scale ultra-high resolution instrument will require formation flying and computational image deconvolution. Significant progress has been made in overcoming these challenges, and some recent results in these areas are discussed. A simple design for a sounding rocket concept demonstration payload is presented that obtains 80 MAS (0.080 arcsec) imaging with a 100 mm diameter photon sieve to image Fe XIV 334 and Fe XVI 335. These images will show the structure of the corona at a resolution never before obtained, and they will also allow a study of the temperature structure in the dissipation region.

  7. Functional studies using NMR

    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

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

    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 1H, 11B, 27Al, 29Si, and 31P. 24 refs.; 7 figs.; 1 table

  9. Renal transplant NMR

    The preliminary results of NMR evaluation of renal transplants (Txs) are reported including correlation with nuclear medicine (NM) and ultrasound (US). Thirteen Txs (8 cadaver (Cd), 5 living related doner (LRD) in 13 patients (6M, 7F) ranging in age from 25-47 (x 35) were evaluated by NM (32), NMR (15) and US (5). Clinical diagnoses included: rejection (8), ATN (2), infarction (1), and normal (2). Of the 8 patients with rejection (5) Cd; 3 LRD) pathologic proof was obtained in 3. An experimental 0.12 T resistive magnet (GE) was used with a partial saturation technique with repetition time (TR) of 143 and 286 msec to provide T1 weighting. T2 weighted information was obtained with a spin echo technique with echo times (TE) of 20, 40, 60 and 80 msec. The NMR appearance of normal Txs consisted of a uniform signal intensity (Tx> pelvic musculature), well-defined internal architecture with good cortical medullary differentiation and normal appearing vessels. The NMR appearance of abnormal transplants consisted of a heterogeneous or overall decrease in signal intensity (kidney muscle) with poor cortical medullary differentiation with or without a halo of decreased signal intensity. Although NMR was able to differentiate normal from abnormal, it was unable to clearly discriminate between ATN and rejection. Advantages of NMR included the ability to demonstrate regional anatomy, vasculature, post operative fluid collections and hematomas, and associated avascular necrosis of the hips

  10. An Improved NMR Study of Liposomes Using 1-Palmitoyl-2-oleoyl-sn-glycero-3-phospatidylcholine as Model

    AnnaLaura Segre

    2006-05-01

    Full Text Available In this paper we report a comparative characterization of Small UnilamellarVesicles (SUVs, Large Unilamellar Vesicles (LUVs and Multilamellar Vesicles (MLVsprepared from 1-palmitoyl-2-oleoyl-sn-glycero-3-phospatidylcholine (POPC, carried outusing two NMR techniques, namely High Resolution NMR in solution and HighResolution–Magic Angle Spinning (HR-MAS. The size and size distributions of thesevesicles were investigated using the dynamic light scattering technique. An improvedassignment of the 1H-NMR spectrum of MLVs is also reported.

  11. MODIS Airborne simulator (MAS) Final Report for CLASIC

    Thomas Arnold; Steven Platnick

    2010-11-24

    The MAS was flown aboard the NASA ER-2 for the CLASIC field experiment, and for all data collected, provided calibrated and geolocated (Level-1B) radiance data for it’s 50 spectral bands (ranging in wavelength for 0.47 to 14.3 µm). From the Level-1B data, as directed in the Statement of Work, higher order (Level-2) data products were derived. The Level-2 products include: a) cloud optical thickness, b) cloud effective radius, c) cloud top height (temperature), d) cloud fraction, e) cloud phase products. Preliminary Level-1B and Level-2 products were provided during the field experiment (typically within one or two days of data collection). Final version data products were made available in December 2008 following considerable calibration analysis. Data collection, data processing (to Level-2), and discussion of the calibration work are summarized below.

  12. The MAS Six Years in Power in Bolivia

    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.

  13. Solid state NMR studies of gels derived from low molecular mass gelators.

    Nonappa; Kolehmainen, E

    2016-07-13

    Since its invention more than six decades ago, nuclear magnetic resonance (NMR) spectroscopy has evolved as an inevitable part of chemical as well as structural analysis of small molecules, polymers, biomaterials and hybrid materials. In the solution state, due to the increased viscosity of complex viscoelastic fluids such as gels, liquid crystals and other soft materials, the rate of molecular tumbling is reduced, which in turn affects the chemical shift anisotropy, dipolar and quadrupolar interactions. As a consequence the solution state NMR spectra show broad lines, and therefore, extracting detailed structural information is a challenging task. In this context, solid state (SS) NMR has the ability to distinguish between a minute amount of polymorphic forms, conformational changes, and the number of non-equivalent molecules in an asymmetric unit of a crystal lattice, and to provide both qualitative as well as quantitative analytical data with a short-range order. Therefore, SS NMR has continued to evolve as an indispensable tool for structural analysis and gave birth to a new field called NMR crystallography. Solid state cross polarization (CP) and high resolution (HR) magic angle spinning (MAS) NMR spectroscopy has been used to study weak interactions in polymer gels. However, the application of SS NMR spectroscopy to study gels derived from low molecular weight gelators has been limited until recently. In this review, we will focus on the importance of solid state NMR spectroscopy in understanding and elucidating the structure of supramolecular gels derived from low molecular weight gelators with selected examples. PMID:27374054

  14. Solid-State NMR Characterization of Mixed Phosphonic Acid Ligand Binding and Organization on Silica Nanoparticles.

    Davidowski, Stephen K; Holland, Gregory P

    2016-04-01

    As ligand functionalization of nanomaterials becomes more complex, methods to characterize the organization of multiple ligands on surfaces is required. In an effort to further the understanding of ligand-surface interactions, a combination of multinuclear ((1)H, (29)Si, (31)P) and multidimensional solid-state nuclear magnetic resonance (NMR) techniques was utilized to characterize the phosphonic acid functionalization of fumed silica nanoparticles using methylphosphonic acid (MPA) and phenylphosphonic acid (PPA). (1)H → (29)Si cross-polarization (CP)-magic angle spinning (MAS) solid-state NMR was used to selectively detect silicon atoms near hydrogen atoms (primarily surface species); these results indicate that geminal silanols are preferentially depleted during the functionalization with phosphonic acids. (1)H → (31)P CP-MAS solid-state NMR measurements on the functionalized silica nanoparticles show three distinct resonances shifted upfield (lower ppm) and broadened compared to the resonances of the crystalline ligands. Quantitative (31)P MAS solid-state NMR measurements indicate that ligands favor a monodentate binding mode. When fumed silica nanoparticles were functionalized with an equal molar ratio of MPA and PPA, the MPA bound the nanoparticle surface preferentially. Cross-peaks apparent in the 2D (1)H exchange spectroscopy (EXSY) NMR measurements of the multiligand sample at short mixing times indicate that the MPA and PPA are spatially close (≤5 Å) on the surface of the nanostructure. Furthermore, (1)H-(1)H double quantum-single quantum (DQ-SQ) back-to-back (BABA) 2D NMR spectra further confirmed that MPA and PPA are strongly dipolar coupled with observation of DQ intermolecular contacts between the ligands. DQ experimental buildup curves and simulations indicate that the average distance between MPA and PPA is no further than 4.2 ± 0.2 Å. PMID:26914738

  15. Food Waste Composting Study from Makanan Ringan Mas

    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.

  16. Characterization of Al30 in commercial poly-aluminum chlorohydrate by solid-state (27)Al NMR spectroscopy.

    Phillips, Brian L; Vaughn, John S; Smart, Scott; Pan, Long

    2016-08-15

    Investigation of commercially produced hydrolysis salts of aluminum by solid-state (27)Al NMR spectroscopy and size-exclusion chromatography (SEC) reveals well-defined and distinct Al environments that can be related to physicochemical properties. (27)Al MAS and MQ-MAS NMR spectroscopic data show that the local structure of the solids is dominated by moieties that closely resemble the Al30 polyoxocation (Al30O8(OH)56(H2O)26(18+)), accounting for 72-85% of the total Al. These Al30-like clusters elute as several size fractions by SEC. Comparison of the SEC and NMR results indicates that the Al30-like clusters includes intact isolated clusters, moieties of larger polymers or aggregates, and possibly fragments resembling δ-Al13 Keggin clusters. The coagulation efficacy of the solids appears to correlate best with the abundance of intact Al30-like clusters and of smaller species available to promote condensation reactions. PMID:27232539

  17. New 34Cl proton-threshold states and the thermonuclear 33S(p,gamma)34Cl rate in ONe novae

    Parikh, A; Hertenberger, R; Krücken, R; Schafstadler, D; Wirth, H -F; Behrens, T; Bildstein, V; Bishop, S; Eppinger, K; Herlitzius, C; Hinke, C; Schlarb, M; Seiler, D; Wimmer, K

    2009-01-01

    Analysis of presolar grains in primitive meteorites has shown isotopic ratios largely characteristic of the conditions thought to prevail in various astrophysical environments. A possible indicator for a grain of ONe nova origin is a large 33S abundance: nucleosynthesis calculations predict as much as 150 times the solar abundance of 33S in the ejecta of nova explosions on massive ONe white dwarfs. This overproduction factor may, however, vary by factors of at least 0.01 - 3 because of uncertainties of several orders of magnitude in the 33S(p,gamma)34Cl reaction rate at nova peak temperatures (Tpeak ~ 0.1 - 0.4 GK). These uncertainties arise due to the lack of nuclear physics information for states within ~ 600 keV of the 33S+p threshold in 34Cl (Sp(34Cl) = 5143 keV). To better constrain this rate we have measured, for the first time, the 34S(3He,t)34Cl reaction over the region Ex(34Cl) = 4.9 - 6 MeV. We confirm previous states and find 15 new states in this energy region. New 33S(p,gamma)34Cl resonances at E...

  18. Synthesis and solid state NMR characterization of novel peptide/silica hybrid materials.

    Werner, Mayke; Heil, Andreas; Rothermel, Niels; Breitzke, Hergen; Groszewicz, Pedro Braga; Thankamony, Aany Sofia; Gutmann, Torsten; Buntkowsky, Gerd

    2015-11-01

    The successful synthesis and solid state NMR characterization of silica-based organic-inorganic hybrid materials is presented. For this, collagen-like peptides are immobilized on carboxylate functionalized mesoporous silica (COOH/SiOx) materials. A pre-activation of the silica material with TSTU (O-(N-Succinimidyl)-N,N,N',N'-tetramethyluronium tetrafluoroborate) is performed to enable a covalent binding of the peptides to the linker. The success of the covalent immobilization is indicated by the decrease of the (13)C CP-MAS NMR signal of the TSTU moiety. A qualitative distinction between covalently bound and adsorbed peptide is feasible by (15)N CP-MAS Dynamic Nuclear Polarization (DNP). The low-field shift of the (15)N signal of the peptide's N-terminus clearly identifies it as the binding site. The DNP enhancement allows the probing of natural abundance (15)N nuclei, rendering expensive labeling of peptides unnecessary. PMID:26411982

  19. 13C NMR spectroscopy of methane adsorbed in SAPO-11 molecular sieve

    Koskela, Tuomas; Ylihautala, Mika; Vaara, Juha; Jokisaari, Jukka

    1996-10-01

    Static 13C and 13C-{ 1H} NMR spectra of carbon-13 enriched methane ( 13CH 4) adsorbed into SAPO-11 molecular sieve were recorded at variable temperatures. Moreover, the corresponding MAS NMR spectra were measured. These experiments reveal a temperature-dependent, anisotropic and asymmetric 13C nuclear shielding tensor. Ab initio model calculations of methane in the field of a positive point charge suggest that the deformation of the shielding tensor may be related to the interaction between the methane molecule and the charge-compensating protons. A comparison with existing Xe data is made.

  20. Multinuclear NMR analysis of the antitubercular drug ethionamide

    Vale, Nuno; Correia, Alexandra; Figueiredo, Patrícia; Santos, Hélder A.

    2016-02-01

    Tuberculosis remains as the deadliest bacterial infection in developing countries, a situation that is particularly aggravated by the increasing spread of multidrug resistant mycobacteria (MDR-TB). In this view, not only new anti-tubercular drugs are urgently needed, but also a better understanding of the existing ones may aid in the future design of more efficient derivatives or surrogates. Ethionamide (ETA) is an anti-tubercular pro-drug used as second-line therapy against MDR-TB, being bio-activated by the mycobacterial monooxygenase EtA. ETA has been the focus of several research works, devoted either to the identification of ETA's metabolites or to the development of novel derivatives potentially useful to fight against tuberculosis. In either case, structural analysis of ETA and related structures is of undeniable relevance, while the presence of sulfur in ETA's structure brings about the possibility of including 33S-NMR in the toolbox of structural analysis techniques. In this work, we have engaged into a multinuclear NMR characterization of ETA, through the study of the drug's solubility in seven deuterated solvents, and of the chemical shifts for different nuclei in ETA. Results showed which are the best conditions to study ETA by NMR and provided some important evidence on the low reactivity of the drug's thioamide group, which may be of relevance for future drug derivatization approaches.

  1. Solid-state NMR enhanced by dynamic nuclear polarization as a novel tool for ribosome structural biology.

    Gelis, Ioannis; Vitzthum, Veronika; Dhimole, Neha; Caporini, Marc A; Schedlbauer, Andreas; Carnevale, Diego; Connell, Sean R; Fucini, Paola; Bodenhausen, Geoffrey

    2013-06-01

    The impact of Nuclear Magnetic Resonance (NMR) on studies of large macromolecular complexes hinges on improvements in sensitivity and resolution. Dynamic nuclear polarization (DNP) in the solid state can offer improved sensitivity, provided sample preparation is optimized to preserve spectral resolution. For a few nanomoles of intact ribosomes and an 800 kDa ribosomal complex we demonstrate that the combination of DNP and magic-angle spinning NMR (MAS-NMR) allows one to overcome current sensitivity limitations so that homo- and heteronuclear (13)C and (15)N NMR correlation spectra can be recorded. Ribosome particles, directly pelleted and frozen into an NMR rotor, yield DNP signal enhancements on the order of ~25-fold and spectra that exhibit narrow linewidths, suitable for obtaining site-specific information. We anticipate that the same approach is applicable to other high molecular weight complexes. PMID:23689811

  2. Solid-state NMR enhanced by dynamic nuclear polarization as a novel tool for ribosome structural biology

    The impact of Nuclear Magnetic Resonance (NMR) on studies of large macromolecular complexes hinges on improvements in sensitivity and resolution. Dynamic nuclear polarization (DNP) in the solid state can offer improved sensitivity, provided sample preparation is optimized to preserve spectral resolution. For a few nanomoles of intact ribosomes and an 800 kDa ribosomal complex we demonstrate that the combination of DNP and magic-angle spinning NMR (MAS-NMR) allows one to overcome current sensitivity limitations so that homo- and heteronuclear 13C and 15N NMR correlation spectra can be recorded. Ribosome particles, directly pelleted and frozen into an NMR rotor, yield DNP signal enhancements on the order of ∼25-fold and spectra that exhibit narrow linewidths, suitable for obtaining site-specific information. We anticipate that the same approach is applicable to other high molecular weight complexes.

  3. Perencanaan Disain Deep Dig Arm pada Kapal Water Witch Untuk Pengerukan Sampah di Kali Mas Surabaya

    Tony Bambang Musriyadi; Erno Setyawan; Irfan Syarif Arief

    2014-01-01

    Kali Mas merupaka salah satu Sungai di Surabaya yang bermanfaat bagi hajat hidup penduduk Surabaya,Namun seiring berjalan waktu Kali Mas mengalami pendangkalan dan polusi sampah padat akibat pembuangan sampah sembarangan.Oleh karena itu penting untuk melakuakan pengerukan sendimen dan sampah yang efektif dan tepat agar tidak menggangu fungsi utama dari Kali Mas,maka perlu suatu alat untuk pengerukan,Backhoe dreger merupak alat yang tepat untuk pengerukan, akan tetapi harus disesuaikan lengan ...

  4. MOS-2: A Two-Dimension Space for Positioning MAS Organizational Models

    Abbas, Hosny; Shaheen, Samir

    2015-01-01

    The increased complexity and dynamism of present and future Multi-Agent Systems (MAS) enforce the need for considering both of their static (design-time) and the dynamic (run-time) aspects. A type of balance between the two aspects can definitely give better results related to system stability and adaptivity. MAS organization is the research area that is concerned with these issues and it is currently a very active and interesting research area. Designing a MAS with an initial organization an...

  5. An HR-MAS MR Metabolomics Study on Breast Tissues Obtained with Core Needle Biopsy

    MuLan Li; Yonghyun Song; Nariya Cho; Jung Min Chang; Hye Ryoung Koo; Ann Yi; Hyeonjin Kim; Sunghyouk Park; Woo Kyung Moon

    2011-01-01

    BACKGROUND: Much research has been devoted to the development of new breast cancer diagnostic measures, including those involving high-resolution magic angle spinning (HR-MAS) magnetic resonance (MR) spectroscopic techniques. Previous HR-MAS MR results have been obtained from post-surgery samples, which limits their direct clinical applicability. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, we performed HR-MAS MR spectroscopic studies on 31 breast tissue samples (13 cancer and 18 non...

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

    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 27Al MAS NMR line at δ = 36.26 indicating the presence of a single tetrahedral aluminium species. Where as 29Si and 31P 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). 27Al 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. Phosphorus 31 solid state NMR characterization of oligonucleotides covalently bound to a solid support.

    Macdonald, P M; Damha, M J; Ganeshan, K; Braich, R; Zabarylo, S V

    1996-01-01

    31P cross polarization (CP) magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectra were acquired for various linear and branched di- and tri-nucleotides attached to a controlled pore glass (CPG) solid support. The technique readily distinguishes the oxidation state of the phosphorus atom (phosphate versus phosphate), the presence or absence of a protecting group attached directly to phosphorus (cyanoethyl), and other large changes in the phosphorus chemistry (phosphate versus pho...

  8. Powder NMR crystallography of new polyanhydride injectable microbead formulations of decitabine

    Brus, Jiří; Švec, P.; Czernek, Jiří; Husak, M.; Hrubý, Martin; Kobera, Libor; Urbanová, Martina; Policianová, Olivia

    Aveiro: University of Aveiro, 2015. s. 28. [International conference on Advanced Nanomaterials /6./, International conference on Graphene Technology /1./, International conference on Hydrogen Energy /1./ - ANM2015. 20.07.2015-22.07.2015, Aveiro] R&D Projects: GA ČR(CZ) GA14-03636S; GA MPO(CZ) FR-TI4/625 Institutional support: RVO:61389013 Keywords : MAS NMR * buccal films * ciclopirox Subject RIV: CD - Macromolecular Chemistry

  9. Solid-state NMR study of stability of geopolymers prepared from alkaline activated metakaoline

    Brus, Jiří; Urbanová, Martina; Koloušek, D.; Andertová, J.

    Zagreb : Faculty of Science & Faculty of Mining, Geology and Petroleum Engineering , University of Zagreb, 2006 - (Vlahovic, I.; Tibljaš, D.). s. 31 ISBN 953-6076-09-8. [Mid-European Clay Conference /3./. 18.09.2006-23.9.2006, Opatia] R&D Projects: GA ČR GA103/03/0506; GA MŠk 2B06120 Institutional research plan: CEZ:AV0Z40500505 Keywords : geopolymers * MAS NMR Subject RIV: JI - Composite Materials

  10. NMR Aerosolomics: Novel NMR Method for Organic Aerosol Analysis

    Horník, Štěpán; Schwarz, Jaroslav; Sýkora, Jan

    - : -, 2015, s. 162. ISBN N. [Small Molecule NMR Conference - SMASH 2015. Baveno (IT), 20.09.2015-23.09.2015] Institutional support: RVO:67985858 Keywords : aerosol * analysis * NMR Subject RIV: CC - Organic Chemistry