Sample records for lanthanide-induced phosphorus-31 nmr

  1. Phosphorus-31 NMR studies of E. coli ribosomes.

    PubMed Central

    Tritton, T R; Armitage, I M

    1978-01-01

    Phosphorus-31 nuclear magnetic resonance spectra, relaxation times and nuclear Overhauser (NOE) enhancement have been measured for E. coli ribosomes, subunits and rRNA. NOE and T1 experiments reveal that the phosphorus relaxation in this organelle is largely dipolar in origin. Moreover these results imply the presence of internal motion within the RNA chain with a correlation time of about 3-5 x 10(-9) sec. In all cases the predominant resonance is centered at about -1.5 ppm (relative to 85% H3PO4) as expected for a phosphodiester linkage where there is a large degree of double helix. The linewidth narrows by about a factor of four when the ribosomal proteins are removed indicating a substantial immobilization of the RNA when it is assembled into the ribosome. In addition to the phosphodiester resonance, ribosomes also reveal one or two narrower resonances shifted to low field by 1-4 ppm. Based on the observation that these resonances show a pH dependent chemical shift, we assign them to phosphate monoesters i.e. terminal 3' or 5' phosphate groups. These terminal phosphates are due to short oligomers of RNA derived from the terminus of the chain. PMID:31604

  2. Phosphonato complexes of platinum(II): kinetics of formation and phosphorus-31 NMR characterization studies

    Microsoft Academic Search

    L. L. Slavin; R. N. Bose

    1990-01-01

    Reactions of cis-diamminedichloroplatinum(II) with phosphonoformic acid (PFA), phosphonoacetic acid (PAA), and methylenediphosphonic acid (MDP) yield various phosphonatoplatinum(II) chelates which were characterized by phosphorus-31 NMR spectroscopy. The P-31 resonances for the chelates appear at 6-12 ppm downfield as compared to the uncomplexed ligands. All complexes exhibit monoprotic acidic behavior in the pH range 2-10. The chemical shift-pH profiles yielded acidity constants,

  3. Phosphonato complexes of platinum(II): kinetics of formation and phosphorus-31 NMR characterization studies.

    PubMed

    Slavin, L L; Bose, R N

    1990-12-01

    Reactions of cis-diamminedichloroplatinum(II) with phosphonoformic acid (PFA), phosphonoacetic acid (PAA), and methylenediphosphonic acid (MDP) yield various phosphonatoplatinum(II) chelates which were characterized by phosphorus-31 NMR spectroscopy. The P-31 resonances for the chelates appear at 6-12 ppm downfield as compared to the uncomplexed ligands. All complexes exhibit monoprotic acidic behavior in the pH range 2-10. The chemical shift-pH profiles yielded acidity constants, 1.0 x 10(-4), 1.5 x 10(-4), and 1.3 x 10(-6) M-1, for the PFA, PAA, and MDP chelates. In addition to the monomeric chelate, MDP formed a bridged diplatinum(II,II) complex when it reacted with cis-Pt (NH3)2(H2O)2(2)+. The P-31 resonance for this binuclear complex appears at 22 ppm downfield from the unreacted ligand. Rate data for the complexation reactions of the phosphonate ligands with the dichloroplatinum complex are consistent with a mechanism in which a monodentate complex is formed initially through rate-limiting aquation process of the platinum complex, followed by a rapid chelation. For the PFA and PAA complexes, initial binding sites are the carboxylato oxygens. Implications of the various binding modes of the phosphonates in relationship to their antiviral activities are discussed. PMID:2150856

  4. Phosphonato complexes of platinum(II): kinetics of formation and phosphorus-31 NMR characterization studies

    SciTech Connect

    Slavin, L.L.; Bose, R.N. (Chemistry Department, Kent State University, OH (USA))

    1990-12-01

    Reactions of cis-diamminedichloroplatinum(II) with phosphonoformic acid (PFA), phosphonoacetic acid (PAA), and methylenediphosphonic acid (MDP) yield various phosphonatoplatinum(II) chelates which were characterized by phosphorus-31 NMR spectroscopy. The P-31 resonances for the chelates appear at 6-12 ppm downfield as compared to the uncomplexed ligands. All complexes exhibit monoprotic acidic behavior in the pH range 2-10. The chemical shift-pH profiles yielded acidity constants, 1.0 x 10(-4), 1.5 x 10(-4), and 1.3 x 10(-6) M-1, for the PFA, PAA, and MDP chelates. In addition to the monomeric chelate, MDP formed a bridged diplatinum(II,II) complex when it reacted with cis-Pt (NH3)2(H2O)2(2)+. The P-31 resonance for this binuclear complex appears at 22 ppm downfield from the unreacted ligand. Rate data for the complexation reactions of the phosphonate ligands with the dichloroplatinum complex are consistent with a mechanism in which a monodentate complex is formed initially through rate-limiting aquation process of the platinum complex, followed by a rapid chelation. For the PFA and PAA complexes, initial binding sites are the carboxylato oxygens. Implications of the various binding modes of the phosphonates in relationship to their antiviral activities are discussed.

  5. Nucleophilic Substitution Reactions Using Phosphine Nucleophiles: An Introduction to Phosphorus-31 NMR

    ERIC Educational Resources Information Center

    Sibbald, Paul A.

    2015-01-01

    Nuclear magnetic resonance (NMR) spectroscopy is commonly used in modern synthetic chemistry to monitor the conversion of reactants to products. Since instruction in the use of NMR spectroscopy typically does not occur until after the introduction of nucleophilic substitution reactions, organic chemistry students are not able to take advantage of…

  6. Synthesis and characterization of polyphosphazene copolymers using phosphorus-31 NMR spectroscopy

    SciTech Connect

    Stewart, F.F.; Peterson, E.S.; Stone, M.L. [Lockheed Martin Idaho Technologies Co., Idaho Falls, ID (United States); Singler, R.E. [Military Academy, West Point, NY (United States). Dept. of Chemistry

    1997-01-01

    It was observed that competitive nucleophilic addition processes may be observed by {sup 31}P NMR spectroscopy. Methoxyethoxyethanol (MEE) and p-methoxyphenol readily substitute for chlorineonto phosphorus and the relative rates are generally comparable to each other. Sterically, the phenol presents is slightly larger than MEE but this does not appear to effect substitution judging by the observed PN(OAr){sub 2} NMR signal. These processes are still being studied.

  7. Quantitative Phosphorus31 NMR Analysis of Lignins, a New Tool for the Lignin Chemist

    Microsoft Academic Search

    Dimitris S. Argyropoulos

    1994-01-01

    A novel quantitative method has been developed for the determination of the various types of hydroxyl groups present in lignins. The syringyl, guaiacyl and p-hydroxyphenyl free phenolic groups, as well as the primary, and the secondary hydroxyl groups (belonging to individual erythro and threo forms of the aryl-glycerol ?-O-4 ether strctures) can be quantitatively determined from a P NMR experiment.

  8. Contribution of protein phosphorylation to binding-induced folding of the SLBP-histone mRNA complex probed by phosphorus-31 NMR.

    PubMed

    Thapar, Roopa

    2014-01-01

    Phosphorus-31 ((31)P) NMR can be used to characterize the structure and dynamics of phosphorylated proteins. Here, I use (31)P NMR to report on the chemical nature of a phosphothreonine that lies in the RNA binding domain of SLBP (stem-loop binding protein). SLBP is an intrinsically disordered protein and phosphorylation at this threonine promotes the assembly of the SLBP-RNA complex. The data show that the (31)P chemical shift can be a good spectroscopic probe for phosphate-coupled folding and binding processes in intrinsically disordered proteins, particularly where the phosphate exhibits torsional strain and is involved in a network of hydrogen-bonding interactions. PMID:25379382

  9. Solid-state phosphorus-31 NMR spectroscopy of a multiple-spin system: an investigation of a rhodium-triphosphine complex.

    PubMed

    Bernard, Guy M; Feindel, Kirk W; Wasylishen, Roderick E; Cameron, T Stanley

    2008-09-28

    Phosphorus-31 NMR spectra of solid [tris(dimethylphenylphosphine)](2,5-norbornadiene) rhodium(I) hexafluorophosphate have been acquired at several applied magnetic field strengths. The phosphorus nuclei of the three phosphine ligands are spin-spin coupled to each other and to 103Rh, resulting in complex NMR spectra; however, the three phosphorus chemical shift (CS) tensors were determined through the analysis of NMR spectra of slow magic angle spinning and stationary samples. Spectra of spinning samples in rotational resonance and two-dimensional 31P NMR spectra were particularly useful for determining the magnitudes of the indirect spin-spin couplings, and to probe their signs. Despite being in similar environments, the three phosphorus nuclei of the phosphine ligands have distinct CS tensors. In particular, the spans of these tensors, delta11-delta33, range from 80 to 176 ppm. The phosphorus CS tensors have been assigned to specific sites determined by X-ray crystallography, based on a combination of the experimental results and the results of quantum chemical calculations of the phosphorus shielding and 2J(31P,31P) values. The effect of coordination of dimethylphenylphosphine with rhodium has been investigated by comparing calculated phosphorus CS tensors for the uncoordinated ligand with those obtained for the ligands in the complex. PMID:18956090

  10. Phosphorus-31 NMR magnetization transfer measurements of metabolic reaction rates in the rat heart and kidney in vivo

    SciTech Connect

    Koretsky, A.P.

    1984-08-01

    This dissertation is concerned with the measurement of the rates of ATP synthesis in the rat kidney and of the creatine kinase catalyzed reaction in the rat heart in situ. Chronically implanted detection coils, employing a balanced matching configuration of capacitors in the tuned circuit, were used to obtain /sup 31/P NMR spectra from heart, kidney, and liver in situ. Gated spectra of heart obtained at systole and diastole and the effects of fructose on kidney and liver were studied. The ability to observe other nuclei using implanted coils is illustrated with /sup 39/K NMR spectra from kidney and muscle. The theoretical considerations of applying magnetization transfer techniques to intact organs are discussed with emphasis on the problems associated with multiple exchange reactions and compartmentation of reactants. Experimental measurements of the ATP synthesis rate (13 ..mu..mol/min/gm tissue) were compared to whole kidney oxygen consumption and Na/sup +/ reabsorption rates to derive ATP/O (0.8 to 1.7) and Na/sup +//ATP (4 to 10) values. The problems associated with ATP synthesis rate measurements in kidney, e.g., the heterogeneity of the inorganic phosphate resonance, are discussed and experiments to overcome these problems proposed.

  11. Phosphorus-31 NMR magnetization transfer measurements of metabolic reaction rates in the rat heart and kidney in vivo

    SciTech Connect

    Koretsky, A.P.

    1984-01-01

    /sup 31/P NMR is a unique tool to study bioenergetics in living cells. The application of magnetization transfer techniques to the measurement of steady-state enzyme reaction rates provides a new approach to understanding the regulation of high energy phosphate metabolism. This dissertation is concerned with the measurement of the rates of ATP synthesis in the rat kidney and of the creatine kinase catalyzed reaction in the rat heart in situ. The theoretical considerations of applying magnetization transfer techniques to intact organs are discussed with emphasis on the problems associated with multiple exchange reactions and compartmentation of reactants. Experimental measurements of the ATP synthesis rate were compared to whole kidney oxygen consumption and Na/sup +/ reabsorption rates to derive ATP/O values. The problems associated with ATP synthesis rate measurements in kidney, e.g. the heterogeneity of the inorganic phosphate resonance, are discussed and experiments to overcome these problems proposed. In heart, the forward rate through creatine kinase was measured to be larger than the reverse rate. To account for the difference in forward and reverse rates a model is proposed based on the compartmentation of a small pool of ATP.

  12. Sodium transport and phosphorus metabolism in sodium-loaded yeast: simultaneous observation with sodium-23 and phosphorus-31 NMR spectroscopy in vivo

    Microsoft Academic Search

    Herbert Hoefeler; Dye Jensen; Martin M. Pike; Jean L. Delayre; Vincent P. Cirillo; Charles S. Springer; Eric T. Fossel; James A. Balschi

    1987-01-01

    Simultaneous ²³Na and ³¹P NMR spectra were obtained from a number of yeast suspensions. Prior to NMR spectroscopy, the yeast cells were Na-loaded: this replaced some of the intracellular K\\/sup +\\/ with Na\\/sup +\\/. These cells were also somewhat P-deficient in that they had no polyphosphate species visible in the ³¹P NMR spectrum. In the NMR experiments, the Na-loaded cells

  13. Characteristics and assessment of biogenic phosphorus in sediments from the multi-polluted Haihe River, China, using phosphorus fractionation and phosphorus-31 nuclear magnetic resonance (31P-NMR)

    NASA Astrophysics Data System (ADS)

    Zhang, W. Q.; Zhang, H.; Tang, W. Z.; Shan, B. Q.

    2013-10-01

    We studied the phosphorus (P) pollution, as described by concentrations, distribution and transformation potential, of sediments of the water scarce and heavily polluted Fuyang River, a tributary of the Haihe River, using P fractionation and phosphorus-31 nuclear magnetic resonance (31P-NMR).The sediments of the Fuyang River accumulate significant amounts of inorganic phosphorus (Pi) and organic phosphorus (Po) from industrial and domestic wastewater and agricultural non-point pollution. In terms of their contribution to total phosphorus, the rank order of the P fractions was as follows: H2SO4-P > NaOH-Pi > Res-P > NaOH-Po > KCl-P and their average relative proportions were 69.7:47.5:15.9:2.9:1.0 (the proportion was based on the average proportion of the KCl-P). Seven P compounds were detected by the 31P-NMR analysis. Orthophosphate (Ortho-P: 45.2-92.4%) and orthophosphate monoesters (mono-P: 6.6-45.7%) were the dominant forms. Smaller amounts of pyrophosphates (pyro-P: 0.1-6.6%), deoxyribonucleic acid (DNA-P: 0.3-3.9%), phosphonates (phon-P: 0-3.3%), phospholipids (lipids-P: 0-2.7%) and polyphosphate (poly-P: 0-0.04%) were observed in the sediments. Results of P fractionation and 31P-NMR analysis showed that 35% of Pi was labile P, including KCl-P and NaOH-Pi (Fe-P and Al-P). Biogenic-P accounted for 24% of P in the sediments. Analysis of the relationships between P species and water quality indicated that the Po compounds would mineralize to form ortho-P and would be potentially bioavailable for recycling to surface water, supporting further growth of phytoplankton and leading to algal blooms.

  14. Phosphorus-31, sup 15 N, and sup 13 C NMR of glyphosate: Comparison of pH titrations to the herbicidal dead-end complex with 5-enolpyruvoylshikimate-3-phosphate synthase

    SciTech Connect

    Castellino, S.; Leo, G.C.; Sammons, R.D.; Sikorski, J.A. (Monsanto Agricultural Company, St. Louis, MO (USA))

    1989-05-02

    The herbicidal dead-end ternary complex (E{sup S3P}{sub Glyph}) of glyphosate (N-(phosphonomethyl)glycine) with 5-enolpyruvoylshikimate-3-phosphate synthase (EPSPS) and the substrate shikimate 3-phosphate (S3P) has been characterized by {sup 31}P, {sup 15}N, and {sup 13}C NMR. The NMR spectra of EPSPS-bound glyphosate show unique chemical shifts ({delta}) for each of the three nuclei. By {sup 31}P NMR, glyphosate in the dead-end complex is a distinct species 3.5 ppm downfield from free glyphosate. The {sup 13}C signal of glyphosate in the dead-end complex is shifted 4 ppm downfield from that of free glyphosate. The {sup 15}N signal for glyphosate (99%) in the dead-end complex is 5 ppm further downfield than that of any free zwitterionic species and 10 ppm downfield from that of the average free species at pH 10.1. The structures of each ionic state of glyphosate are modeled with force field calculations by using MacroModel. A correlation is made for the {sup 31}P {delta} and the C-P-O bond angle, and the {sup 13}C and {sup 15}N {delta} values are postulated to be related to C-C-O and C-N-C bond angles, respectively. The downfield {sup 31}P chemical shift perturbation for S3P in the EPSPS binary complex is consistent with ionization of the 3-phosphate of S3P upon binding. Comparison with the S3P {sup 31}P {delta} vs pH titration curve specifies predominantly the dianion of the 3-phosphate in the E{sup S3P} binary complex, while the E{sup S3P}{sub Glyph} complex indicates net protonation at the 3-phosphate. Chemical shift perturbations of this latter type may be explained by changes in the O-P-O bond angle.

  15. Flavodoxin from Anabaena 7120: uniform nitrogen-15 enrichment and hydrogen-1, nitrogen-15, and phosphorus-31 NMR investigation of the flavin mononucleotide binding site in the reduced and oxidized states

    SciTech Connect

    Stockman, B.J.; Westler, W.M.; Mooberry, E.S.; Markley, J.L.

    1988-01-12

    Interactions between flavin mononucleotide (FMN) and apoprotein have been investigated in the reduced and oxidized states of the flavodoxin isolated from Anabaena 7120 (M/sub r/ approx. 21,000). /sup 1/H, /sup 15/N, and /sup 31/P NMR have been used to characterize the FMN-protein interactions in both redox states. These are compared with those seen in other flavodoxins. Uniformly enriched (/sup 15/N) flavodoxin was isolated from Anabaena 7120 grown on K/sup 15/NO/sub 3/ as the sole nitrogen source. /sup 15/N insensitive nucleus enhanced by polarization transfer (INEPT) and nuclear Overhauser effect (NOE) studies of this sample provided information regarding protein structure and dynamics. A /sup 1/H-detected /sup 15/N experiment allowed the correlation of nitrogen resonances to those of their attached protons. Over 90% of the expected N-H cross peaks could be resolved in this experiment.

  16. A conformational study of nucleic acid phosphate ester bonds using phosphorus-31 nuclear magnetic resonance.

    PubMed Central

    Haasnoot, C A; Altona, C

    1979-01-01

    A systematic phosphorus-31 nuclear magnetic resonance study of some nucleic acid constituents (6-N-(dimethyl)adenylyl-(3',5')-uridine and some nucleotide methyl esters) is presented. The temperature dependent phosphorus-31 chemical shifts were analyzed by standard thermodynamic procedures. It is shown that gt conformations about the P-O ester bonds have a lower free energy content relative to gg conformers. PMID:440971

  17. Phosphorus-31 nuclear magnetic resonance studies of cellular systems

    SciTech Connect

    Robitaille, P.M.L.

    1986-01-01

    In this study, /sup 31/P-NMR spectroscopy was applied to the study of (1) sipunculan erythrocytes, (2) spermatozoa isolated from several vertebrate and invertebrate species, and (3) unfertilized eggs isolated from the blue crab and the horseshoe crab. /sup 31/P-NMR results center on the identification of key metabolites and on the determination of intracellular pH. In studies involving fish spermatozoa, emphasis was also placed on examining changes in metabolic profiles following (1) an anaerobic insult, (2) motility initiation, or (3) short-term storage. This study also captures several difficulties in spectral interpretation which a spectroscopist is likely to encounter.

  18. Phosphorus-31 MRI of hard and soft solids using quadratic echo line-narrowing

    E-print Network

    Haller, Gary L.

    P in several ex vivo soft tissues. Bone is a composite material (8), containing approximately 45Phosphorus-31 MRI of hard and soft solids using quadratic echo line-narrowing Merideth A. Freya) Magnetic resonance imaging (MRI) of solids is rarely attempted. One of the main reasons is that the broader

  19. Dynamics of phosphate head groups in biomembranes. Comprehensive analysis using phosphorus-31 nuclear magnetic resonance lineshape and relaxation time measurements.

    PubMed

    Dufourc, E J; Mayer, C; Stohrer, J; Althoff, G; Kothe, G

    1992-01-01

    Phospholipid head group dynamics have been studied by pulsed phosphorus-31 nuclear magnetic resonance (31P-NMR) of unoriented and macroscopically aligned dimyristoylphosphatidylcholine model membranes in the temperature range, 203-343 K. Lineshapes and echo intensities have been recorded as a function of interpulse delay times, temperature and macroscopic orientation of the bilayer normal with respect to the magnetic field. The dipolar proton-phosphorus (1H-31P) contribution to the transverse relaxation time, T2E, and to lineshapes was eliminated by means of a proton spin-lock sequence. In case of longitudinal spin relaxation, T1Z, the amount of dipolar coupling was evaluated by measuring the maximum nuclear Overhauser enhancement. Hence, the results could be analyzed by considering chemical shift anisotropy as the only relaxation mechanism. The presence of various minima both in T1Z and T2E temperature plots as well as the angular dependence of these relaxation times allowed description of the dynamics of the phosphate head group in the 31P-NMR time window, by three different motional classes, i.e., intramolecular, intermolecular and collective motions. The intramolecular motions consist of two hindered rotations and one free rotation around the bonds linking the phosphate head group to the glycerol backbone. These motions are the fastest in the hierarchy of time with correlation times varying from less than 10(-12) to 10(-6) s in the temperature range investigated. The intermolecular motions are assigned to phospholipid long axis rotation and fluctuation. They have correlation times ranging from 10(-11) s at high temperatures to 10(-3) s at low temperatures. The slowest motion affecting the 31P-NMR observables is assigned to viscoelastic modes, i.e., so called order director fluctuations and is only detected at high temperatures, above the main transition in pulse frequency dependent T2ECP experiments. Comprehensive analysis of the phosphate head group dynamics is achieved by a dynamic NMR model based on the stochastic Liouville equation. In addition to correlation times, this analysis provides activation energies and order parameters for the various motions, and a value for the bilayer elastic constant. PMID:1540698

  20. Soil and Litter Phosphorus-31 Nuclear Magnetic Resonance Spectroscopy: Extractants, Metals, and Phosphorus Relaxation Times

    E-print Network

    Hemminga, Marcus A.

    .1 to 0.5 M Bu4NOH (Emsleytative, comparative analysis of P forms. However, for 31 P NMR to be and Niazi.0 s for orthophosphate and orthophosphateanalyses of soil and litter samples by solution 31 P NMR spectroscopy monoesters, delay times in use for soil ever possible. 31 P NMR spectroscopy include 20 s (Newman and Tate, 1980

  1. COMPARISON OF P FORMS IN ANIMAL MANURE IDENTIFIED BY ENZYMATIC HYDROLYSIS AND SOLUTION P-31 NMR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Both enzymatic hydrolysis and solution phosphorus-31 NMR spectroscopy have been used in characterizing P forms in animal manure. To date, however, there are no reports comparing the P identified by the two methods. In this study, P in 0.25 M NaOH/0.05 M EDTA extracts of dairy manure and poultry litt...

  2. Phosphorus-31 nuclear magnetic resonance spectroscopic study of the canine pancreas: applications to acute alcoholic pancreatitis

    SciTech Connect

    Janes, N.; Clemens, J.A.; Glickson, J.D.; Cameron, J.L.

    1988-01-01

    The first nuclear magnetic resonance spectroscopic study of the canine pancreas is described. Both in-vivo, ex-vivo protocols and NMR observables are discussed. The stability of the ex-vivo preparation based on the NMR observables is established for at least four hours. The spectra obtained from the in-vivo and ex-vivo preparations exhibited similar metabolite ratios, further validating the model. Metabolite levels were unchanged by a 50% increase in perfusion rate. Only trace amounts of phosphocreatine were observed either in the intact gland or in extracts. Acute alcoholic pancreatitis was mimicked by free fatty acid infusion. Injury resulted in hyperamylasemia, edema (weight gain), increased hematocrit and perfusion pressure, and depressed levels of high energy phosphates.

  3. The phosphorus-31 spectra of dielectrophoretically reoriented tubules in the HII phase of DOPE.

    PubMed

    Osman, P; Cornell, B

    1996-01-31

    31P electric field nuclear magnetic resonance measurements are described which assess the effect of electric field on the orientation of tubules comprising the HII phase of dioeleoylphosphatidylethanolamine. A model, based on dielectrophoretic effects, was used to predict that a field of 4 MV/m would change the orientation of the lipid tubules in a HII phase. The excitation pulse was biphasic to help discriminate electric field interactions with free ions or permanent dipoles from interactions with induced dipoles, as well as to control the problems of ohmic heating, electrolysis and polarisation associated with dc or unbalanced ac excitation voltages. Spectra consistent with irreversible electrorotation and with reversible and transient electrorotation were observed. No response to the electric field was seen in certain cases. The conditions for irreversible and reversible electrorotation and failure to rotate have been tabulated and are discussed. Finally, some simple models are considered, in order to calculate the energies involved, if the observed NMR spectra are interpreted as arising from lipid HII phase reorientations. PMID:8593272

  4. Phosphorus-31 Nuclear Magnetic Resonance Study of the Effect of Pentachlorophenol (PCP) on the Physiologies of PCP-Degrading Microorganisms

    PubMed Central

    Lohmeier-Vogel, Elke M.; Leung, Kam T.; Lee, Hung; Trevors, Jack T.; Vogel, Hans J.

    2001-01-01

    Free and agarose-encapsulated pentachlorophenol (PCP)-degrading Sphingomonas sp. isolates UG25 and UG30 were compared to Sphingomonas chlorophenolica ATCC 39723 with respect to the ability to degrade PCP. Pretreatment of the UG25 and UG30 strains with 50 ?g of PCP per ml enabled the cells to subsequently degrade higher levels of this environmental pollutant. Similar treatment of ATCC 39723 cells had no effect on the level of PCP degraded by this strain. Phosphorus-31 nuclear magnetic resonance spectra of agarose-immobilized strains UG25 and UG30 grown in the absence of PCP showed that there was marked deenergization of the cells upon exposure to a nonlethal concentration of PCP (120 ?g/ml). For example, no transmembrane pH gradient was observed, and the ATP levels were lower than the levels obtained in the absence of PCP. The transmembrane pH gradient and ATP levels were restored once the immobilized cells had almost completely degraded the PCP in the perfusion medium. PCP-pretreated cells, on the other hand, maintained their transmembrane pH gradient and ATP levels even in the presence of high levels of PCP. The ability of PCP-pretreated strain UG25 and UG30 cells to remain energized in the presence of PCP was shown to correlate with an altered membrane phospholipid profile; these cells had a higher concentration of cardiolipin than cells cultured in the absence of PCP. Strain ATCC 39723, which did not degrade higher levels of PCP after PCP pretreatment, did not show this response. PMID:11472931

  5. Effect of Cyclosporine on Hepatic Energy Status and on Fructose Metabolism after Portacaval Shunt in Dog as Monitored by Phosphorus-31 Nuclear Magnetic Resonance Spectroscopy in Vivo

    PubMed Central

    Rossaro, Lorenzo; Mazzaferro, Vincenzo; Scotti-Foglieni, Carlo L.; Williams, Donald S.; Simplaceanu, Elena; Simplaceanu, Virgil; Francavilla, Antonio; Starzl, Thomas E.; Ho, Chien; Van Thiel, David H.

    2010-01-01

    The effect of cyclosporin A on the hepatic energy status and intracellular pH of the liver and its response to a fructose challenge has been investigated using in vivo phosphorus-31 nuclear magnetic resonance spectroscopy in dogs. Three experimental groups were studied: (a) control dogs (n = 5), (b) dogs 4 days after the creation of an end-to-side portacaval shunt (n = 5), and (c) dogs 4 days after portacaval shunt and continuous infusion of cyclosporin A (4 mg/kg/day) by way of the left portal vein (portacaval shunt plus cyclosporin A, n = 5). The phosphorus-31 nuclear magnetic resonance spectra were obtained at 81 MHz using a Bruker BIOSPEC II 4.7-tesla nuclear magnetic resonance system equipped with a 40-cm horizontal bore superconducting solenoid. The phosphomonoesters (p < 0.01), inorganic phosphate and ATP levels (p < 0.05) were decreased significantly in portacaval shunt–treated and in portacaval shunt-plus-cyclosporin A–treated dogs compared with unshunted control dogs. After a fructose challenge (750 mg/kg body wt, intravenously), fructose-1-phosphate metabolism was reduced in portacaval shunt–treated dogs compared with either the normal or portacaval shunt-plus-cyclosporin A–treated dogs (p < 0.05). Both portacaval shunt– and portacaval shunt-plus-cyclosporin A–treated dogs demonstrated a reduced decline in ATP levels after fructose infusion when compared with the controls (p < 0.05). Immediately after the fructose challenge, the intracellular pH decreased from 7.30 ± 0.03 to 7.00 ± 0.05 in all animals (p < 0.01) and then gradually returned to normal over 60 min. These data, obtained in vivo using phosphorus-31 nuclear magnetic resonance spectroscopy of the liver after a portacaval shunt, suggest that: (a) the energy status of the liver is reduced in dogs with a portacaval shunt compared with that of normal controls and (b) cyclosporin A treatment ameliorates the reduction in hepatic metabolism normally observed after a fructose challenge to the liver with a portacaval shunt. PMID:2010174

  6. Determination of the chemical shift of the 1' proton of cytidine 2'-phosphate in the presence and absence of RNase via phosphorus-31 detection of proton-proton decoupling

    NASA Astrophysics Data System (ADS)

    Bolton, Philip H.

    The investigation of the conformations of cellular phosphates in solution typically relies on the interpretation of the chemical shifts and scalar couplings of protons. In many cases of potential interest, such as the binding of cellular phosphates to enzymes, the proton signals are obscured by those of the enzyme. A partial solution to this problem is given by heteronuclear two-dimensional magnetic resonance which allows the determination of proton spectral information via phosphorus-31 detection. The two-dimensional approach bypasses the inability to determine proton spectral information that is obscured in a conventional experiment but is typically limited to reporting only on those protons which are scalar coupled to the phosphorus-31 nucleus. Chemical shift information about an additional group of protons, those coupled to the protons coupled to the phosphorus-31 nucleus, can be determined by phosphorus-31 detection of proton-proton decoupling. This indirect approach observes the effect of proton-proton decoupling on heteronuclear population transfer. The method is used to determine the chemical shift of the 1' proton of cytidine 2'-phosphate in the presence and absence of RNase.

  7. Moving NMR

    Microsoft Academic Search

    Bernhard Blümich; Federico Casanova; Ernesto Danieli; Qingxia Gong; Marcus Greferath; Agnes Haber; Jürgen Kolz; Juan Perlo

    2008-01-01

    Initiated by the use of NMR for well logging, portable NMR instruments are being developed for a variety of novel applications in materials testing and process analysis and control. Open sensors enable non-destructive testing of large objects, and small, cup-size magnets become available for high throughput analysis by NMR relaxation and spectroscopy. Some recent developments of mobile NMR are reviewed

  8. NMR Spectroscopy Protein-NMR

    E-print Network

    Schüler, Axel

    is investigated. 5. Methodological development of selective NMR pulse sequences for the application in bioorganic. Bioorganic & Medicinal Chemistry Volume 19, Issue 11 (2011), 3497­3501. PROTEINENGINEERINGANDBIOANALYTICS

  9. NMR Animations

    NSDL National Science Digital Library

    This site features animated tutorials on NMR with sufficient depth to be useful to the non NMR savvy. The animations are accompanied by short descriptions so that the processes displayed can be understood by the viewer. This site goes beyond just showing precession. There are nice animations showing the effect of different pulses, including composite pulses on the magnetization, the effects of magnetic gradient pulses to measure diffusion and do coherence pathway selection.

  10. NMR tutorial

    NSDL National Science Digital Library

    Bogdal, Dariusz

    This site provides an entry-level introduction to NMR in a text and figures format. The site also contains example structure elucidation problems using NMR, IR and MS data complete with hints and answers. Although the molecules included are somewhat simple, the examples do a good job of illustrating the structure elucidation process. The site also has data for several more complex structure determination problems.

  11. C NMR Spectra C NMR Spectra

    E-print Network

    Collum, David B.

    S16 1 H and 13 C NMR Spectra (see p S3) Me N-i-Pr #12;S17 1 H and 13 C NMR Spectra (see p S3) Me NBn #12;S18 1 H and 13 C NMR Spectra (see p S4) NBn #12;S19 1 H and 13 C NMR Spectra (see p S4) NBn Me Me Me #12;S20 1 H and 13 C NMR Spectra (see p S4) N-n-Bu Me Me Me #12;S21 1 H and 13 C NMR Spectra

  12. Analysis of monoglycerides, diglycerides, sterols, and free fatty acids in coconut (Cocos nucifera L.) oil by 31P NMR spectroscopy.

    PubMed

    Dayrit, Fabian M; Buenafe, Olivia Erin M; Chainani, Edward T; de Vera, Ian Mitchelle S

    2008-07-23

    Phosphorus-31 nuclear magnetic resonance spectroscopy ( (31)P NMR) was used to differentiate virgin coconut oil (VCO) from refined, bleached, deodorized coconut oil (RCO). Monoglycerides (MGs), diglycerides (DGs), sterols, and free fatty acids (FFAs) in VCO and RCO were converted into dioxaphospholane derivatives and analyzed by (31)P NMR. On the average, 1-MG was found to be higher in VCO (0.027%) than RCO (0.019%). 2-MG was not detected in any of the samples down to a detection limit of 0.014%. On the average, total DGs were lower in VCO (1.55%) than RCO (4.10%). When plotted in terms of the ratio [1,2-DG/total DGs] versus total DGs, VCO and RCO samples grouped separately. Total sterols were higher in VCO (0.096%) compared with RCO (0.032%), and the FFA content was 8 times higher in VCO than RCO (0.127% vs 0.015%). FFA determination by (31)P NMR and titration gave comparable results. Principal components analysis shows that the 1,2-DG, 1,3-DG, and FFAs are the most important parameters for differentiating VCO from RCO. PMID:18576656

  13. Identification of trapped and boundary lipid binding sites in M13 coat protein/lipid complexes by deuterium NMR spectroscopy

    SciTech Connect

    Van Gorkom, L.C.; Horvath, L.I.; Hemminga, M.A.; Sternberg, B.; Watts, A. (Univ. of Oxford (England))

    1990-04-24

    The major coat protein of M13 bacteriophage has been incorporated into bilayers of 1,2-dimyristoyl-sn-glycero-3-phosphocholine, deuterated in the trimethyl segments of the choline headgroup (DMPC-d9). Two-component deuterium and phosphorus-31 NMR spectra have been observed from bilayer complexes containing the coat protein, indicating slow exchange (on the deuterium quadrupole anisotropy and phosphorus-31 chemical shift averaging time scales) of lipid molecules of less than 10(3) Hz between two motionally distinct environments in the complexes. The fraction of the isotropic spectral component increases with increasing M13 protein concentration, and this component is attributed to lipid headgroups, which are disordered relative to their order in protein-free bilayers. The activation energy of the fast local motions of the trimethyl groups of the choline residue in the headgroup decreases from 23 kJ mol-1 in the pure lipid bilayers to 20 kJ mol-1 for the protein-associated lipid headgroups. The chemical exchange rate of lipid molecules between the two motionally distinct environments has been estimated to be 20-50 Hz by steady-state line-shape simulations of the deuterium spectra of DMPC-d9/M13 coat protein complexes using exchange-coupled modified Bloch equations. The off-rate was, as expected from one-to-one exchange, independent of the L/P ratio; tau off -1 = 0.23 kHz. It is suggested that the protein-associated lipid may be trapped between closely packed parallel aggregates of M13 coat protein and that the high local concentration of protein in a one-dimensional arrangement in lipid bilayers may be required for the fast reassembly of phage particles before release from an infected cell.

  14. 1H and 31P NMR Lipidome of Ethanol-Induced Fatty Liver

    PubMed Central

    Fernando, Harshica; Kondraganti, Shakuntala; Bhopale, Kamlesh K.; Volk, David E.; Neerathilingam, Muniasamy; Kaphalia, Bhupendra S.; Luxon, Bruce A.; Boor, Paul J.; Ansari, G. A. Shakeel

    2011-01-01

    Background Hepatic steatosis (fatty liver), an early and reversible stage of alcoholic liver disease, is characterized by triglyceride deposition in hepatocytes, that can advance to steatohepatitis, fibrosis, cirrhosis, and ultimately to hepatocellular carcinoma. In the present work, we studied altered plasma and hepatic lipid metabolome (lipidome) to understand the mechanisms and lipid pattern of early stage alcohol induced-fatty liver. Methods Male Fischer 344 rats were fed 5% alcohol in a Lieber-DeCarli diet. Control rats were pair-fed an equivalent amount of maltose-dextrin. After one month, animals were sacrificed and plasma collected. Livers were excised for morphological, immunohistochemical, and biochemical studies. The lipids from plasma and livers were extracted with methyl-tert-butyl ether and analyzed by 750/800 MHz proton nuclear magnetic resonance (1H NMR) and phosphorus (31P) NMR spectroscopy on a 600 MHz spectrometer. The NMR data were then subjected to multivariate statistical analysis. Results Hemotoxylin & Eosin and Oil Red O stained liver sections showed significant fatty infiltration. Immunohistochemical analysis of liver sections from ethanol-fed rats showed no inflammation (absence of CD3 positive cells) or oxidative stress (absence of malondialdehyde reactivity or 4-hydroxynonenal positive straining). Cluster analysis and principal component analysis of 1H NMR data of lipid extracts of both plasma and livers showed a significant difference in the lipid metabolome of ethanol-fed vs. control rats. 31P NMR data of liver lipid extracts showed significant changes in phospholipids similar to 1H NMR data. 1H NMR data of plasma and liver reflected several changes while comparison of 1H NMR and 31P NMR data offered a correlation among the phospholipids. Conclusions Our results show that alcohol consumption alters metabolism of cholesterol, triglycerides and phospholipids that could contribute to the development of fatty liver. These studies also indicate that fatty liver precedes oxidative stress and inflammation. The similarities observed in plasma and liver lipid profiles offer a potential methodology for detecting early stage alcohol-induced fatty liver disease by analyzing the plasma lipid profile. PMID:20682011

  15. Soils, Pores, and NMR

    Microsoft Academic Search

    Andreas Pohlmeier; Sabina Haber-Pohlmeier; Agnes Haber; Oscar Sucre; Laura Stingaciu; Siegfried Stapf; Bernhard Blümich

    2010-01-01

    Within Cluster A, Partial Project A1, the pore space exploration by means of Nuclear Magnetic Resonance (NMR) plays a central role. NMR is especially convenient since it probes directly the state and dynamics of the substance of interest: water. First, NMR is applied as relaxometry, where the degree of saturation but also the pore geometry controls the NMR signature of

  16. Fundamentals of NMR

    NSDL National Science Digital Library

    James, Thomas L.

    This e-text presents an introduction to the fundamentals of NMR covering magnetic resonance, pulsed NMR, relaxation, chemical shift, spin-spin coupling, the nuclear Overhauser effect and chemical exchange. The document may be downloaded in PDF format.

  17. NMR analysis of biodiesel

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  18. 31P-NMR SPECTROSCOPY OF RAT LIVER DURING SIMPLE STORAGE OR CONTINUOUS HYPOTHERMIC PERFUSION1

    PubMed Central

    Rossaro, Lorenzo; Murase, Noriko; Caldwell, Cary; Farghali, Hassan; Casavilla, Adrian; Starzl, Thomas E.; Ho, Chien; Van Thiel, David H.

    2010-01-01

    SUMMARY The ATP content and intracellular pH (pHi)3 of isolated rat liver before, during, and after cold preservation in either UW-lactobionate (UW, n=10) or Euro-Collins (EC, n=8) solutions were monitored using phosphorus-31 nuclear magnetic resonance (31P-NMR) spectroscopy. The 31P-NMR spectra were obtained on a 4.7-Tesla system operating at 81 MHz. Fructose metabolism, liver enzyme release, O2 consumption, and rat survival after liver transplantation were also evaluated. During simple cold storage (SCS), the ATP level declined to undetectable levels with both preservation solutions while the pHi declined to approximately 7.0. In contrast, during continuous hypothermic perfusion (CHP), hepatic ATP levels remained measurable during the 24-hour EC preservation and actually increased significantly (p>0.01) during UW preservation. After reperfusion at 37°C with Krebs-lactate, the SCS livers treated with EC differed significantly from the UW livers in terms of their ATP and pHi as well as their response to a fructose challenge. In contrast, livers undergoing CHP demonstrated similar behaviors with both solutions. These results demonstrate an increase in the hepatic ATP content during CHP which occurs with UW but is not seen with EC. On the other hand, only livers that were simply stored with UW achieved significant survival after transplant, while CHP livers were affected by vascular damage as demonstrated by fatal thrombosis after transplant. These data suggest that ATP content is not the only determinant of good liver function although a system of hypothermic perfusion might further improve liver preservation efficacy should injury to vascular endothelium be avoided. PMID:1402332

  19. Two dimensional NMR spectroscopy

    SciTech Connect

    Schram, J.; Bellama, J.M.

    1988-01-01

    Two dimensional NMR represents a significant achievement in the continuing effort to increase solution in NMR spectroscopy. This book explains the fundamentals of this new technique and its analytical applications. It presents the necessary information, in pictorial form, for reading the ''2D NMR,'' and enables the practicing chemist to solve problems and run experiments on a commercial spectrometer by using the software provided by the manufacturer.

  20. Understanding NMR Spectroscopy

    NSDL National Science Digital Library

    Keeler, James

    This site provides links to a series of PDF files that represent chapters of an e-text on the basics of NMR. While many other textbooks on NMR are available, the chief merit of this one is that it has a nice chapter on the NMR instrumentation (ch. 5) which should be accessible to undergraduates. The text also provides a relatively mathematics-free or maybe more accurately Dirac bracket notation-free introduction to 1-D and 2-D (COSY and NOESY) experiments that would be appreciated by advanced undergraduates or beginning graduate students involved in undergraduate research experiences using NMR.

  1. Flow measurements by NMR

    Microsoft Academic Search

    A. Caprihan; E. Fukushima

    1990-01-01

    We review the current status of liquid flow velocity studies by pulsed nuclear magnetic resonance (NMR). NMR is a non-invasive method that is most sensitive to protons, so that, combined with the recently developed imaging capabilities, it is now possible to obtain images of hydrodynamic parameters of interest for most common liquids. Such parameters can include, besides velocity, diffusion coefficient,

  2. NMR Spectroscopy - Theory

    NSDL National Science Digital Library

    Lord, J.R.

    This web site begins with a simple quantum description of NMR and proceeds to introduce resonance absorption, relaxation, chemical shifts, and scalar couplings. This site will be useful for advanced undergraduate students needing a description of NMR that is more detailed than that given in most introductory Organic texts.

  3. Basics of NMR

    NSDL National Science Digital Library

    Hornak, Joseph P.

    Dr. Joseph Hornak of the Rochester Institute of Technology presents this high quality hypertextbook for in-depth coverage of the physics and technique behind Nuclear Magnetic Resonance (NMR) (For Dr. Hornak's Basics of MRI, see the August 4, 1999 Scout Report for Science & Engineering). The material is presented in a detailed and clear manner without over simplifying the concepts. Chapters include "The Mathematics of NMR," "Spin Physics," "NMR Spectroscopy," "Fourier Transforms," "Pulse Sequences," and much more. A chapter on "NMR Hardware" offers an overview of components (like the superconducting magnet and various coils) used in most NMR systems. The "Practical Considerations" chapter emphasizes spectroscopic techniques. With the screen split into two separate frames, explanatory graphics can be viewed alongside the text. A glossary and a list of symbols are also included in this carefully produced textbook.

  4. C-13 NMR 68 Chem 355 Jasperse C-13 NMR

    E-print Network

    Jasperse, Craig P.

    isotopes for carbon, nitrogen, and oxygen are all NMR inactive! Fortunately at least carbon-13 is active carbon-13 NMR; later we will use hydrogen NMR. Both of these will be used later in the year, especially that have quantized spin states are referred to as "NMR active". Just as electrons have quantized spin

  5. NMR IN BIOMEDICINE NMR Biomed. in press

    E-print Network

    Loening, Niko

    . Copyright # 2005 John Wiley & Sons, Ltd. KEYWORDS: 31 P edited 1 H NMR; INEPT; choline compounds; human.interscience.wiley.com). DOI:10.1002/nbm.973 Quantification of phosphocholine and glycerophosphocholine with 31 P edited 1 H. Here, a new scheme that uses 31 P edited 1 H spectroscopy to quantify the concentrations of choline, PC

  6. NMR imaging microscopy

    SciTech Connect

    Not Available

    1986-10-01

    In the past several years, proton nuclear magnetic resonance (NMR) imaging has become an established technique in diagnostic medicine and biomedical research. Although much of the work in this field has been directed toward development of whole-body imagers, James Aguayo, Stephen Blackband, and Joseph Schoeninger of the Johns Hopkins University School of Medicine working with Markus Hintermann and Mark Mattingly of Bruker Medical Instruments, recently developed a small-bore NMR microscope with sufficient resolution to image a single African clawed toad cell (Nature 1986, 322, 190-91). This improved resolution should lead to increased use of NMR imaging for chemical, as well as biological or physiological, applications. The future of NMR microscopy, like that of many other newly emerging techniques, is ripe with possibilities. Because of its high cost, however, it is likely to remain primarily a research tool for some time. ''It's like having a camera,'' says Smith. ''You've got a way to look at things at very fine levels, and people are going to find lots of uses for it. But it is a very expensive technique - it costs $100,000 to add imaging capability once you have a high-resolution NMR, which itself is at least a $300,000 instrument. If it can answer even a few questions that can't be answered any other way, though, it may be well worth the cost.''

  7. Catalytic mechanism of ?-phosphate attack in dUTPase is revealed by X-ray crystallographic snapshots of distinct intermediates, 31P-NMR spectroscopy and reaction path modelling

    PubMed Central

    Barabás, Orsolya; Németh, Veronika; Bodor, Andrea; Perczel, András; Rosta, Edina; Kele, Zoltán; Zagyva, Imre; Szabadka, Zoltán; Grolmusz, Vince I.; Wilmanns, Matthias; Vértessy, Beáta G.

    2013-01-01

    Enzymatic synthesis and hydrolysis of nucleoside phosphate compounds play a key role in various biological pathways, like signal transduction, DNA synthesis and metabolism. Although these processes have been studied extensively, numerous key issues regarding the chemical pathway and atomic movements remain open for many enzymatic reactions. Here, using the Mason–Pfizer monkey retrovirus dUTPase, we study the dUTPase-catalyzed hydrolysis of dUTP, an incorrect DNA building block, to elaborate the mechanistic details at high resolution. Combining mass spectrometry analysis of the dUTPase-catalyzed reaction carried out in and quantum mechanics/molecular mechanics (QM/MM) simulation, we show that the nucleophilic attack occurs at the ?-phosphate site. Phosphorus-31 NMR spectroscopy (31P-NMR) analysis confirms the site of attack and shows the capability of dUTPase to cleave the dUTP analogue ?,?-imido-dUTP, containing the imido linkage usually regarded to be non-hydrolyzable. We present numerous X-ray crystal structures of distinct dUTPase and nucleoside phosphate complexes, which report on the progress of the chemical reaction along the reaction coordinate. The presently used combination of diverse structural methods reveals details of the nucleophilic attack and identifies a novel enzyme–product complex structure. PMID:23982515

  8. Catalytic mechanism of ?-phosphate attack in dUTPase is revealed by X-ray crystallographic snapshots of distinct intermediates, 31P-NMR spectroscopy and reaction path modelling.

    PubMed

    Barabás, Orsolya; Németh, Veronika; Bodor, Andrea; Perczel, András; Rosta, Edina; Kele, Zoltán; Zagyva, Imre; Szabadka, Zoltán; Grolmusz, Vince I; Wilmanns, Matthias; Vértessy, Beáta G

    2013-12-01

    Enzymatic synthesis and hydrolysis of nucleoside phosphate compounds play a key role in various biological pathways, like signal transduction, DNA synthesis and metabolism. Although these processes have been studied extensively, numerous key issues regarding the chemical pathway and atomic movements remain open for many enzymatic reactions. Here, using the Mason-Pfizer monkey retrovirus dUTPase, we study the dUTPase-catalyzed hydrolysis of dUTP, an incorrect DNA building block, to elaborate the mechanistic details at high resolution. Combining mass spectrometry analysis of the dUTPase-catalyzed reaction carried out in and quantum mechanics/molecular mechanics (QM/MM) simulation, we show that the nucleophilic attack occurs at the ?-phosphate site. Phosphorus-31 NMR spectroscopy ((31)P-NMR) analysis confirms the site of attack and shows the capability of dUTPase to cleave the dUTP analogue ?,?-imido-dUTP, containing the imido linkage usually regarded to be non-hydrolyzable. We present numerous X-ray crystal structures of distinct dUTPase and nucleoside phosphate complexes, which report on the progress of the chemical reaction along the reaction coordinate. The presently used combination of diverse structural methods reveals details of the nucleophilic attack and identifies a novel enzyme-product complex structure. PMID:23982515

  9. NMR in molecular crystals

    NASA Astrophysics Data System (ADS)

    Decressain, R.; Amoureux, J. P.; Carpentier, L.; Nagy, J. B.

    The 1H, 19F and 13C relaxation times of fluoroadamantane C10H15F are measured over a wide temperature range. These relaxation times are analysed with two dynamical descriptions: an isotropic rotational diffusion and a Frenkel jump model. In this jump model, the structural equilibrium positions are taken into account and therefore two molecular motions are able to explain adequately the experimental results obtained in the plastic phase: a three-fold uniaxial rotation around the dipolar C-F axis and a tumbling reorientation of this axis between <111> cubic axes. The refinements are first carried out using 1H and 19F NMR results in conjunction with the residence time deduced from the dielectric relaxation. Finally, by introducing the 13C NMR results obtained in the plastic phase a precise determination of the two residence time can be made from the NMR results alone.

  10. NMR Relaxation and Petrophysical Properties

    Microsoft Academic Search

    Marc Fleury

    2011-01-01

    NMR relaxation is routinely used in the field of geosciences to give basic petrophysical properties such as porosity, pore size distribution, saturation etc. In this tutorial, we focus on the pore size distribution deduced from NMR. We recall the basic principle used in the interpretation of the NMR signal and compare the results with other standard petrophysical techniques such as

  11. 224} studied by NMR

    SciTech Connect

    Furukawa, Y; Fang, X; Kögerler, P

    2014-05-14

    7Li nuclear magnetic resonance (NMR) studies have been performed to investigate magnetic properties and spin dynamics of Mn3+ (S = 2) spins in the giant polyoxometalate molecule {Mn40W224}. The 7Li-NMR line width is proportional to the external magnetic field H as expected in a paramagnetic state above 3 K. Below this temperature the line width shows a sudden increase and is almost independent of H, which indicates freezing of the local Mn3+ spins. The temperature dependence of T1 for both 1H and 7Li reveals slow spin dynamics at low temperatures, consistent with spin freezing. The slow spin dynamics is also evidenced by the observation of a peak of 1/T2 around 3 K, where the fluctuation frequency of spins is of the order of ~200 kHz. An explicit form of the temperature dependence of the fluctuation frequency of Mn3+ spins is derived from the nuclear relaxation data.

  12. NMR Studies of Peroxidases.

    NASA Astrophysics Data System (ADS)

    Veitch, Nigel Charles

    Available from UMI in association with The British Library. Requires signed TDF. Peroxidases are a haem-containing group of enzymes with a wide diversity of function within biological systems. While a common characteristic is the ability to catalyse the conversion of hydrogen peroxide to water, it is the accompanying processes of hormone synthesis and degradation which have generated such a high level of interest. However, information at the molecular level is limited to a single well-resolved crystal structure, that of yeast cytochrome c peroxidase. This thesis presents a strategy for the investigation of peroxidase structure and function based on proton nuclear magnetic resonance spectroscopy, a technique which has the ability to address aspects of both protein structure and protein dynamics in solution. The application of one- and two-dimensional NMR techniques has been developed in the context of plant peroxidases, notably the isoenzyme HRP-C derived from the horseradish root. Characterisation of the proton NMR spectra of HRP -C in resting and ligated states provided new information enabling the structure of the binding site for aromatic donor molecules, such as indole-3-propionic, ferulic and benzhydroxamic acids, to be resolved. In order to overcome difficulties encountered with a protein of the complexity of peroxidase, additional information was obtained from chemical shift parameters and the use of peroxidase variants produced by site-directed mutagenesis. A comparative study using NMR spectroscopy was undertaken for wild-type recombinant HRP-C expressed in Escherichia coli, and two protein variants with substitutions made to residues located on the distal side of the haem pocket, Phe41 to Val and Arg38 to Lys. NMR analyses of a plant peroxidase from barley grains and the fungal peroxidase from Coprinus cinereus were also successful using methods conceived with HRP-C. Examination of three specifically constructed recombinant protein variants of C. cinereus peroxidase was essential in confirming the identity of residues participating in the aromatic donor molecule binding site of peroxidases.

  13. NMR in biology and medicine

    SciTech Connect

    Chien, S.; Chien, H.

    1986-01-01

    This volume explores the applications of NMR in basic biological research and in clinical diagnosis. The contributors highlight the capabilities of NMR as a tool for studying living organisms at the molecular and cellular levels and detecting abnormalities in various organ systems. Included are solid-state and high-resolution NMR studies of the molecular structure and dynamic interactions of lipids, proteins, and nucleic acids. The latest developments in NMR zeugmatographic imaging and in musculoskeletal and cardiovascular magnetic resonance imaging are detailed. Concluding chapters review the uses of in vivo NMR spectroscopy to study energy metabolism and cellular biochemistry. Emphasis is placed on in vivo NMR spectroscopy studies that elucidate normal metabolic functions and their pathological disturbances.

  14. NMR Investigations of Nanostructured Ceramics

    Microsoft Academic Search

    M. Edgar; M. Schubert; H. H. Limbach

    Nanostructured mesoporous silicates displaying hexagonally arranged channels, templated using a liquid crystal mesophase, were investigated using H-2 and N-15 NMR spectroscopy. It is shown that N-I5 MAS NMR spec- troscopy allows to estimate the surface acidity of mesoporous materials by measuring the N-H bond length via the N-15 chemical shift. Further, H-2 and N-15 NMR spectroscopy identify significant differences between

  15. THz Dynamic Nuclear Polarization NMR

    PubMed Central

    Nanni, Emilio A.; Barnes, Alexander B.; Griffin, Robert G.; Temkin, Richard J.

    2013-01-01

    Dynamic nuclear polarization (DNP) increases the sensitivity of nuclear magnetic resonance (NMR) spectroscopy by using high frequency microwaves to transfer the polarization of the electrons to the nuclear spins. The enhancement in NMR sensitivity can amount to a factor of well above 100, enabling faster data acquisition and greatly improved NMR measurements. With the increasing magnetic fields (up to 23 T) used in NMR research, the required frequency for DNP falls into the THz band (140–600 GHz). Gyrotrons have been developed to meet the demanding specifications for DNP NMR, including power levels of tens of watts; frequency stability of a few megahertz; and power stability of 1% over runs that last for several days to weeks. Continuous gyrotron frequency tuning of over 1 GHz has also been demonstrated. The complete DNP NMR system must include a low loss transmission line; an optimized antenna; and a holder for efficient coupling of the THz radiation to the sample. This paper describes the DNP NMR process and illustrates the THz systems needed for this demanding spectroscopic application. THz DNP NMR is a rapidly developing, exciting area of THz science and technology. PMID:24639915

  16. Achievement of 1020MHz NMR.

    PubMed

    Hashi, Kenjiro; Ohki, Shinobu; Matsumoto, Shinji; Nishijima, Gen; Goto, Atsushi; Deguchi, Kenzo; Yamada, Kazuhiko; Noguchi, Takashi; Sakai, Shuji; Takahashi, Masato; Yanagisawa, Yoshinori; Iguchi, Seiya; Yamazaki, Toshio; Maeda, Hideaki; Tanaka, Ryoji; Nemoto, Takahiro; Suematsu, Hiroto; Miki, Takashi; Saito, Kazuyoshi; Shimizu, Tadashi

    2015-07-01

    We have successfully developed a 1020MHz (24.0T) NMR magnet, establishing the world's highest magnetic field in high resolution NMR superconducting magnets. The magnet is a series connection of LTS (low-Tc superconductors NbTi and Nb3Sn) outer coils and an HTS (high-Tc superconductor, Bi-2223) innermost coil, being operated at superfluid liquid helium temperature such as around 1.8K and in a driven-mode by an external DC power supply. The drift of the magnetic field was initially ±0.8ppm/10h without the (2)H lock operation; it was then stabilized to be less than 1ppb/10h by using an NMR internal lock operation. The full-width at half maximum of a (1)H spectrum taken for 1% CHCl3 in acetone-d6 was as low as 0.7Hz (0.7ppb), which was sufficient for solution NMR. On the contrary, the temporal field stability under the external lock operation for solid-state NMR was 170ppb/10h, sufficient for NMR measurements for quadrupolar nuclei such as (17)O; a (17)O NMR measurement for labeled tri-peptide clearly demonstrated the effect of high magnetic field on solid-state NMR spectra. PMID:25978708

  17. NMR molecular photography

    E-print Network

    Anatoly K. Khitrin; Vladimir L. Ermakov; B. M. Fung

    2002-08-21

    A procedure is described for storing a 2D pattern consisting of 32x32 = 1024 bits in a spin state of a molecular system and then retrieving the stored information as a stack of NMR spectra. The system used is a nematic liquid crystal, the protons of which act as spin clusters with strong intramolecular interactions. The technique used is a programmable multi-frequency irradiation with low amplitude. When it is applied to the liquid crystal, a large number of coherent long-lived 1H response signals can be excited, resulting in a spectrum showing many sharp peaks with controllable frequencies and amplitudes. The spectral resolution is enhanced by using a second weak pulse with a 90 phase shift, so that the 1024 bits of information can be retrieved as a set of well-resolved pseudo-2D spectra reproducing the input pattern.

  18. THz Dynamic Nuclear Polarization NMR

    E-print Network

    Nanni, Emilio Alessandro

    Dynamic nuclear polarization (DNP) increases the sensitivity of nuclear magnetic resonance (NMR) spectroscopy by using high frequency microwaves to transfer the polarization of the electrons to the nuclear spins. The ...

  19. Compact orthogonal NMR field sensor

    DOEpatents

    Gerald, II, Rex E. (Brookfield, IL); Rathke, Jerome W. (Homer Glen, IL)

    2009-02-03

    A Compact Orthogonal Field Sensor for emitting two orthogonal electro-magnetic fields in a common space. More particularly, a replacement inductor for existing NMR (Nuclear Magnetic Resonance) sensors to allow for NMR imaging. The Compact Orthogonal Field Sensor has a conductive coil and a central conductor electrically connected in series. The central conductor is at least partially surrounded by the coil. The coil and central conductor are electrically or electro-magnetically connected to a device having a means for producing or inducing a current through the coil and central conductor. The Compact Orthogonal Field Sensor can be used in NMR imaging applications to determine the position and the associated NMR spectrum of a sample within the electro-magnetic field of the central conductor.

  20. NMR characterization of thin films

    DOEpatents

    Gerald, II, Rex E. (Brookfield, IL); Klingler, Robert J. (Glenview, IL); Rathke, Jerome W. (Homer Glen, IL); Diaz, Rocio (Chicago, IL); Vukovic, Lela (Westchester, IL)

    2008-11-25

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

  1. Optical pumping and xenon NMR

    SciTech Connect

    Raftery, M.D.

    1991-11-01

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

  2. Optical pumping and xenon NMR

    SciTech Connect

    Raftery, M.D.

    1991-11-01

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

  3. NMR insights into protein allostery

    PubMed Central

    Manley, Gregory; Loria, J. Patrick

    2014-01-01

    Allosterism is one of nature's principal methods for regulating protein function. Allosterism utilizes ligand binding at one site to regulate the function of the protein by modulating the structure and dynamics of a distant binding site. In this review, we first survey solution NMR techniques and how they may be applied to the study of allostery. Subsequently, we describe several examples of application of NMR to protein allostery and highlight the unique insight provided by this experimental technique. PMID:22198279

  4. Multispectral Analysis of NMR Imagery

    NASA Technical Reports Server (NTRS)

    Butterfield, R. L.; Vannier, M. W. And Associates; Jordan, D.

    1985-01-01

    Conference paper discusses initial efforts to adapt multispectral satellite-image analysis to nuclear magnetic resonance (NMR) scans of human body. Flexibility of these techniques makes it possible to present NMR data in variety of formats, including pseudocolor composite images of pathological internal features. Techniques do not have to be greatly modified from form in which used to produce satellite maps of such Earth features as water, rock, or foliage.

  5. NMR Relaxation and Petrophysical Properties

    NASA Astrophysics Data System (ADS)

    Fleury, Marc

    2011-03-01

    NMR relaxation is routinely used in the field of geosciences to give basic petrophysical properties such as porosity, pore size distribution, saturation etc. In this tutorial, we focus on the pore size distribution deduced from NMR. We recall the basic principle used in the interpretation of the NMR signal and compare the results with other standard petrophysical techniques such as mercury pore size distribution, BET specific surface measurements, thin section visualizations. The NMR pore size distribution is a unique information available on water saturated porous media and can give similar results as MICP in certain situations. The scaling of NMR relaxation time distribution (s) into pore sizes (?m) requires the knowledge of the surface relaxivity (?m/s) and we recommend using specific surface measurements as an independent determination of solid surface areas. With usual surface relaxivities, the NMR technique can explore length-scales starting from nano-meters and ending around 100 ?m. Finally, we will introduce briefly recent techniques sensitive to the pore to pore diffusional exchange, providing new information on the connectivity of the pore network, but showing another possibility of discrepancy in the determination of pore size distribution with standard techniques.

  6. Gerhard Wider: Technical aspects of NMR spectroscopy with biological macromolecules .... Technical aspects of NMR spectroscopy

    E-print Network

    Wider, Gerhard

    Gerhard Wider: Technical aspects of NMR spectroscopy with biological macromolecules .... -1- Technical aspects of NMR spectroscopy with biological macromolecules and studies of hydration in solution aspects of NMR spectroscopy with biological macromolecules .... -2- Contents 1. Introduction 5 2. Basic

  7. jsNMR: an embedded platform-independent NMR spectrum viewer.

    PubMed

    Vosegaard, Thomas

    2015-04-01

    jsNMR is a lightweight NMR spectrum viewer written in JavaScript/HyperText Markup Language (HTML), which provides a cross-platform spectrum visualizer that runs on all computer architectures including mobile devices. Experimental (and simulated) datasets are easily opened in jsNMR by (i) drag and drop on a jsNMR browser window, (ii) by preparing a jsNMR file from the jsNMR web site, or (iii) by mailing the raw data to the jsNMR web portal. jsNMR embeds the original data in the HTML file, so a jsNMR file is a self-transforming dataset that may be exported to various formats, e.g. comma-separated values. The main applications of jsNMR are to provide easy access to NMR data without the need for dedicated software installed and to provide the possibility to visualize NMR spectra on web sites. PMID:25641013

  8. FAST-NMR: Functional Annotation Screening Technology Using NMR Spectroscopy

    E-print Network

    Powers, Robert

    .; Fellenberg, M.; Heumann, K.; Mewes, H.-W. Nucleic Acids Res. 2003, 31, 207. (4) Kanehisa, M.; Goto, S.; Kawashima, S.; Okuno, Y.; Hattori, M. Nucleic Acids Res. 2004, 32, D277. Figure 1. Functional information-ligand interactions are determined through a tiered NMR screen using a library composed of compounds with known

  9. A SENSITIVE NMR THERMOMETER FOR MULTINUCLEI FT NMR

    EPA Science Inventory

    A pernicious problem in multinuclei FT NMR is accurate measurement of sample temperature. This arises from several factors including widespread use of high-power decoupling, large sample tubes (with potentially large temperature gradients across the sample volume), and lack of su...

  10. Using NMR for ligand discovery and optimization

    Microsoft Academic Search

    Hugo O Villar; Jiangli Yan; Mark R Hansen

    2004-01-01

    Several recent technology-driven advances in the area of NMR have rekindled an interest in the application of the technology to problems in drug discovery and development. A unique aspect of NMR is that it has applicability in broadly different areas of the drug discovery and optimization processes. NMR techniques for screening aimed at the discovery of novel ligands or low

  11. Quality Assessment of Horticultural Products by NMR

    Microsoft Academic Search

    B. P HILLS; C. J CLARK

    2003-01-01

    The potential for developing NMR as an on-line sensor of the internal quality of fruits and vegetables is discussed. The literature on the NMR of horticultural products is first surveyed for potentially useful correlations between NMR characteristics and internal quality factors in commercially important harvested products. This is followed by discussions on the cellular origins of these correlations and of

  12. Applications of NMR to food science

    Microsoft Academic Search

    E Alberti; P. S Belton; A. M Gil

    2002-01-01

    This report reviews the literature on the applications of NMR to food science from 1995 until March 2001. In order to be able to keep the number of references to manageable proportions, the number of papers referred to has been limited to those applications where NMR plays a major role in the experimental programme. Applications where NMR is simply used

  13. NMR spectroscopic analysis of lotusine.

    PubMed

    Yang, Jian

    2005-02-01

    Lotusine, a soluble alkaloid, is one of the major constituents of the Chinese medicine Lotus Plumule, and has antihypertension and antibacterial activity. In order to confirm the structures reported in the literature by explicit 1H and 13C assignments, we applied a series of NMR experiments including 1H-1H COSY, HSQC and HMBC. PMID:15562520

  14. Petrophysical applications of NMR imaging

    SciTech Connect

    Rothwell, W.P.; Vinegar, H.J.

    1985-12-01

    A system for obtaining high-resolution NMR images of oil field cores is described. Separate proton density and T/sub 2/ relaxation images are obtained to distinguish spatial variations of fluid-filled porosity and the physical nature of the pores. Results are presented for typical sandstones.

  15. Using NMR for ligand discovery and optimization.

    PubMed

    Villar, Hugo O; Yan, Jiangli; Hansen, Mark R

    2004-08-01

    Several recent technology-driven advances in the area of NMR have rekindled an interest in the application of the technology to problems in drug discovery and development. A unique aspect of NMR is that it has applicability in broadly different areas of the drug discovery and optimization processes. NMR techniques for screening aimed at the discovery of novel ligands or low molecular weight structures for fragment-based build up procedures are being applied commonly in the industry. Application of NMR in structure-guided drug design and metabonomics are also becoming routine. We present an overview of some of the most recent NMR developments in these areas. PMID:15288248

  16. Role for NMR in structural genomics.

    PubMed

    Kennedy, Michael A; Montelione, Gaetano T; Arrowsmith, Cheryl H; Markley, John L

    2002-01-01

    The 2nd EMSL Workshop on Structural Genomics was held on 28th and 29th July 2000 at the Environmental Molecular Sciences Laboratory at the Department of Energy's Pacific Northwest National Laboratory in Richland, WA. The workshop focused on four topics: 1. The role for NMR in structural and functional genomics; 2. The technical challenges NMR faces for structural and functional genomics; 3. The potential need for a national NMR center for structural and functional genomics in the United States; and 4. Organization of the NMR community. This report summarizes the workshop proceedings and conclusions reached regarding the role of NMR in the emerging fields of structural and functional genomics. PMID:12836706

  17. C NMR Spectra (see p S10)

    E-print Network

    Collum, David B.

    S31 1 H and 13 C NMR Spectra (see p S10) NHBn Me Ph 10 #12;S32 1 H and 13 C NMR Spectra (see p S10) NHBn Me Ph 11 #12;S33 1 H and 13 C NMR Spectra (see p S11) NH-i-Pr n-Bu NH-i-Pr n-Bu 12 Me Me 13 #12;S34 1 H and 13 C NMR Spectra (see p S11)NH-i-Pr Me Ph 14 #12;S35 1 H and 13 C NMR Spectra (see p S11

  18. Measuring material susceptibility using NMR

    NASA Astrophysics Data System (ADS)

    SanGiorgio, Paul; Zens, Albert

    2015-06-01

    We report on a method of measuring the high-field susceptibilities of paramagnetic and diamagnetic materials using only a standard NMR system equipped with pulsed field gradients. We demonstrate the accuracy and sensitivity of the technique by measuring a series of 99.9% copper wires with diameters between 0.16 mm and 0.79 mm. We measured the volumetric susceptibility of the copper to be ? = - 9.5 ± 0.2 ·10-6 , which agrees with the literature value of pure copper, - 9.6 ·10-6 . In addition to making quantitative measurements, this technique can also be used to evaluate the effectiveness of compensation schemes used to produce "zero-susceptibility" materials needed for construction of high-resolution NMR probes.

  19. Scalable NMR spectroscopy with semiconductor chips

    PubMed Central

    Ha, Dongwan; Paulsen, Jeffrey; Sun, Nan; Song, Yi-Qiao; Ham, Donhee

    2014-01-01

    State-of-the-art NMR spectrometers using superconducting magnets have enabled, with their ultrafine spectral resolution, the determination of the structure of large molecules such as proteins, which is one of the most profound applications of modern NMR spectroscopy. Many chemical and biotechnological applications, however, involve only small-to-medium size molecules, for which the ultrafine resolution of the bulky, expensive, and high-maintenance NMR spectrometers is not required. For these applications, there is a critical need for portable, affordable, and low-maintenance NMR spectrometers to enable in-field, on-demand, or online applications (e.g., quality control, chemical reaction monitoring) and co-use of NMR with other analytical methods (e.g., chromatography, electrophoresis). As a critical step toward NMR spectrometer miniaturization, small permanent magnets with high field homogeneity have been developed. In contrast, NMR spectrometer electronics capable of modern multidimensional spectroscopy have thus far remained bulky. Complementing the magnet miniaturization, here we integrate the NMR spectrometer electronics into 4-mm2 silicon chips. Furthermore, we perform various multidimensional NMR spectroscopies by operating these spectrometer electronics chips together with a compact permanent magnet. This combination of the spectrometer-electronics-on-a-chip with a permanent magnet represents a useful step toward miniaturization of the overall NMR spectrometer into a portable platform. PMID:25092330

  20. NMR Measures of Heterogeneity Length

    NASA Astrophysics Data System (ADS)

    Spiess, Hans W.

    2002-03-01

    Advanced solid state NMR spectroscopy provides a wealth of information about structure and dynamics of complex systems. On a local scale, multidimensional solid state NMR has elucidated the geometry and the time scale of segmental motions at the glass transition. The higher order correlation functions which are provided by this technique led to the notion of dynamic heterogeneities, which have been characterized in detail with respect to their rate memory and length scale. In polymeric and low molar mass glass formers of different fragility, length scales in the range 2 to 4 nm are observed. In polymeric systems, incompatibility of backbone and side groups as in polyalkylmethacrylates leads to heteogeneities on the nm scale, which manifest themselves in unusual chain dynamics at the glass transition involving extended chain conformations. References: K. Schmidt-Rohr and H.W. Spiess, Multidimensional Solid-State NMR and Polymers,Academic Press, London (1994). U. Tracht, M. Wilhelm, A. Heuer, H. Feng, K. Schmidt-Rohr, H.W. Spiess, Phys. Rev. Lett. 81, 2727 (1998). S.A. Reinsberg, X.H. Qiu, M. Wilhelm, M.D. Ediger, H.W. Spiess, J.Chem.Phys. 114, 7299 (2001). S.A. Reinsberg, A. Heuer, B. Doliwa, H. Zimmermann, H.W. Spiess, J. Non-Crystal. Solids, in press (2002)

  1. Development of LC-13C NMR

    NASA Technical Reports Server (NTRS)

    Dorn, H. C.; Wang, J. S.; Glass, T. E.

    1986-01-01

    This study involves the development of C-13 nuclear resonance as an on-line detector for liquid chromatography (LC-C-13 NMR) for the chemical characterization of aviation fuels. The initial focus of this study was the development of a high sensitivity flow C-13 NMR probe. Since C-13 NMR sensitivity is of paramount concern, considerable effort during the first year was directed at new NMR probe designs. In particular, various toroid coil designs were examined. In addition, corresponding shim coils for correcting the main magnetic field (B sub 0) homogeneity were examined. Based on these initial probe design studies, an LC-C-13 NMR probe was built and flow C-13 NMR data was obtained for a limited number of samples.

  2. Applications of NMR in Dairy Research

    PubMed Central

    Maher, Anthony D.; Rochfort, Simone J.

    2014-01-01

    NMR is a robust analytical technique that has been employed to investigate the properties of many substances of agricultural relevance. NMR was first used to investigate the properties of milk in the 1950s and has since been employed in a wide range of studies; including properties analysis of specific milk proteins to metabolomics techniques used to monitor the health of dairy cows. In this brief review, we highlight the different uses of NMR in the dairy industry. PMID:24958391

  3. NMR in well logging and hydrocarbon exploration

    Microsoft Academic Search

    M. G. Prammer

    2004-01-01

    Nuclear magnetic resonance (NMR) has become a versatile tool for the evaluation of underground hydrocarbon reservoirs. Formation\\u000a attributes such as rock porosity and rock pore size distributions, as well as the relative concentrations of water, oil and\\u000a gas, can be inferred from subsurface NMR. The hydrogen NMR signal encodes porosity as amplitude, pore sizes as relaxation\\u000a times and fluid properties

  4. Access to NMR Spectroscopy for Two-Year College Students: The NMR Site at Trinity University

    ERIC Educational Resources Information Center

    Mills, Nancy S.; Shanklin, Michael

    2011-01-01

    Students at two-year colleges and small four-year colleges have often obtained their exposure to NMR spectroscopy through "canned" spectra because the cost of an NMR spectrometer, particularly a high-field spectrometer, is prohibitive in these environments. This article describes the design of a NMR site at Trinity University in which spectral…

  5. New NMR well logging\\/fracture mapping technique with possible application of SQUID NMR detection

    Microsoft Academic Search

    1981-01-01

    A new method for making NMR measurements has been developed that potentially can receive NMR signals from a precise distance into the geologic formation. It is based on the production of a toroidal region of homogeneous radial magnetic field near the mid-plane between two magnets arranged axially so their fields oppose between them. NMR signals have been detected from such

  6. Introduction to NMR Spectroscopy and Physics. C-13 NMR in more detail than "Summary" 83 Chem 355 Jasperse C-13 NMR

    E-print Network

    Jasperse, Craig P.

    -active nuclei: H-1, C-13, N-15, F-19, P-31, Si-29, Se-79, Sn-119 Some NMR-inactive nuclei: C-12, N-14, O-16Introduction to NMR Spectroscopy and Physics. C-13 NMR in more detail than "Summary" 83 Chem 355 Jasperse C-13 NMR I. Introduction to Spectroscopy Spectroscopy involves gaining information from

  7. University of Oregon CAMCOR NMR Facility Varian NMR Instrument Guidelines (VnmrJ 3.2 software)

    E-print Network

    : carefully clean outside of tube with ethanol prior to bringing the sample to the NMR room to prevent preparation in NMR room no lab gloves in NMR room clean up after yourself... take your samples when you

  8. Using Cloud Storage for NMR Data Distribution

    ERIC Educational Resources Information Center

    Soulsby, David

    2012-01-01

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

  9. NMR techniques in biomedical and pharmaceutical analysis

    Microsoft Academic Search

    M. Malet-Martino; U. Holzgrabe

    2011-01-01

    This article focuses on the description of some of the NMR techniques used in the field of biomedical and pharmaceutical research. Indeed, the NMR method has special characteristics which make it uniquely suitable for these kinds of studies. It is non-selective so that all the low molecular weight compounds in the sample investigated are detected simultaneously in a single run.

  10. Hepatic metabolism by 31 P NMR

    Microsoft Academic Search

    R. A. Iles; J. R. Griffiths

    1982-01-01

    Hepatic metabolism in intact livers has been studied by 3lp nuclear magnetic resonance (NMR) spectroscopy. 3tp NMR spectroscopy of normal liver detects little ADP and much lower amounts of inorganic phosphate than are found by enzymatic or chemical analysis. Ischaemia of 30 min duration provokes a rapid fall in ATP to undetectable levels; reflow restores the ATP concentration to 70%

  11. NMR Properties of Petroleum Reservoir Fluids

    Microsoft Academic Search

    George J. Hirasaki; Ying Zhang

    NMR well logging of petroleum reservoir require the measurement of the NMR response of water, oil, and gas in the pore space of rocks at elevated temperatures and pressures. The viscosity of the oil may range from less than 1 cp to greater than 10,000 cp. Also, the oil and gas are not a single component but rather a broad

  12. Fracture Characterization with NMR Spectroscopic Techniques

    Microsoft Academic Search

    C. T. Philip Chang; Jinli Qiao; Songhua Chen; A. Ted Watson

    1997-01-01

    Determination of suitable techniques and analyses that can be implemented by NMR well logging can greatly improve the characterization of underground petroleum reservoirs and aquifers. In this paper, the feasibility for using various NMR methods for detection and characterization of fractures is explored. Analyses of experimental data obtained with a variety of samples are presented. It is shown that relaxation

  13. Mobile NMR: Measuring Pixels, Images, and Spectra

    Microsoft Academic Search

    Bernhard Bluemich

    2007-01-01

    The vision of bringing nuclear magnetic resonance out of the lab to the doctor's office, the chemical reactor, or the manufacturing site is becoming reality with the development of mobile NMR. Pioneered for well logging in the oil industry, the concept has been explored for materials testing in a more systematic way since the introduction of the NMR-MOUSE. This is

  14. NMR properties of petroleum reservoir fluids

    Microsoft Academic Search

    George J. Hirasaki; Sho-Wei Lo; Ying Zhang

    2003-01-01

    NMR well logging of petroleum reservoir require the measurement of the NMR response of water, oil, and gas in the pore space of rocks at elevated temperatures and pressures. The viscosity of the oil may range from less than 1 cp to greater than 10,000 cp. Also, the oil and gas are not a single component but rather a broad

  15. Solving structures by NMR Qinghua Wang

    E-print Network

    Hardy, Jeanne

    and 15NH4Cl for E. coli). Disadvantage is the substantial cost of isotopic labeling. #12;N H O OH N H O N (BPTI) from NOE derived dist restraints 1987 3D NMR: 13C, 15N labeling of recombinant proteins 1990 as a whole, leading to broad peaks. Problem #1 can be overcome by labeling protein with other NMR- sensitive

  16. C NMR Investigations of Fullerene Black

    Microsoft Academic Search

    M. Kanowski; G. Buntkowsky; H. Werner; M. Wohlers; R. Schlögl; H.-M. Vieth; K. Lüders

    1994-01-01

    Solid-state C NMR measurements on differently treated fullerene black samples are reported. The results show that no significant amounts of C60 molecules are entrapped in fullerene black in a way that they are not accessible for conventionally used toluene extraction. The broad distribution of chemical shifts in the C MAS NMR spectra confirms the large abundance of bent carbon structures

  17. NMR studies of oriented molecules

    SciTech Connect

    Sinton, S.W.

    1981-11-01

    Deuterium and proton magnetic resonance are used in experiments on a number of compounds which either form liquid crystal mesophases themselves or are dissolved in a liquid crystal solvent. Proton multiple quantum NMR is used to simplify complicated spectra. The theory of nonselective multiple quantum NMR is briefly reviewed. Benzene dissolved in a liquid crystal are used to demonstrate several outcomes of the theory. Experimental studies include proton and deuterium single quantum (..delta..M = +-1) and proton multiple quantum spectra of several molecules which contain the biphenyl moiety. 4-Cyano-4'-n-pentyl-d/sub 11/-biphenyl (5CB-d/sub 11/) is studied as a pure compound in the nematic phase. The obtained chain order parameters and dipolar couplings agree closely with previous results. Models for the effective symmetry of the biphenyl group in 5CB-d/sub 11/ are tested against the experimental spectra. The dihedral angle, defined by the planes containing the rings of the biphenyl group, is found to be 30 +- 2/sup 0/ for 5DB-d/sub 11/. Experiments are also described for 4,4'-d/sub 2/-biphenyl, 4,4' - dibromo-biphenyl, and unsubstituted biphenyl.

  18. Picoliter H-1 NMR Spectroscopy

    SciTech Connect

    Minard, Kevin R.(BATTELLE (PACIFIC NW LAB)) [BATTELLE (PACIFIC NW LAB); Wind, Robert A.(BATTELLE (PACIFIC NW LAB)) [BATTELLE (PACIFIC NW LAB)

    2002-02-01

    A RF probe that fits inside the bore of a small gradient coil package is described for routine 1H-NMR microscopy measurements on small samples. The probe operates at 500 MHz and houses a 267-um-diameter solenoid transceiver. When used in three dimensional chemical shift imaging (3D-CSI) experiments, the measured signal-to-noise ratio (SNR) is shown to be within 20-30 percent of theoretical limits formulated by only considering the solenoid's resistive losses. This is illustrated using a 100-um-diameter globule of triacylglycerols ({approx}900mM) that may be an oocyte precursor in young Xenopus Laevis frogs, and water sample containing choline at a concentration often found in live cells ({approx}33mM). In chemical shift images generated using a few thousand scans, the choline methyl line is found to have an acceptable SNR in resolved from just 5 picoliters in the Xenopus globule. It is concluded that the probe's sensitivity is sufficient for performing 1H-NMR on picoliter-scale volumes in biological cells and tissues.

  19. Probing porous media with gas diffusion NMR

    NASA Technical Reports Server (NTRS)

    Mair, R. W.; Wong, G. P.; Hoffmann, D.; Hurlimann, M. D.; Patz, S.; Schwartz, L. M.; Walsworth, R. L.

    1999-01-01

    We show that gas diffusion nuclear magnetic resonance (GD-NMR) provides a powerful technique for probing the structure of porous media. In random packs of glass beads, using both laser-polarized and thermally polarized xenon gas, we find that GD-NMR can accurately measure the pore space surface-area-to-volume ratio, S/V rho, and the tortuosity, alpha (the latter quantity being directly related to the system's transport properties). We also show that GD-NMR provides a good measure of the tortuosity of sandstone and complex carbonate rocks.

  20. On electrophoretic NMR. Exploring high conductivity samples

    NASA Astrophysics Data System (ADS)

    Bielejewski, Micha?; Giesecke, Marianne; Furó, István

    2014-06-01

    The performance of a new electrophoretic NMR (eNMR) method that uses a Carr-Purcell-Meiboom-Gill echo train with repeated electric field reversal is investigated. We show that this pulse sequence, with acronym CPMGER, yields strongly reduced artifacts from convective flow effects caused by the simultaneous presence of electroosmotic and thermal driving forces. We demonstrate the achieved improvements in various aqueous solutions. Ultimately, the method can be used for obtaining electrophoretic mobilities by eNMR without relying on uncharged reference molecules, otherwise a significant limitation for electrophoretic experiments performed with nuclei other than 1H.

  1. NMR-based metabolomics in wine science.

    PubMed

    Hong, Young-Shick

    2011-12-01

    As metabolomics is becoming an emerging field of 'omics' research, NMR serves as one of the major analytical approaches of the decade in metabolomic study, producing information-rich, highly reliable and reproducible data set in non-targeted or global and multivariate statistical analysis. Recently, NMR is successfully being used to characterize wine and find an association of wine metabolite with environmental and fermentative factors in vineyard and making wine. This review describes important analytical features and recent applications in/of NMR-based metabolomics in wine science. PMID:22290704

  2. NMR in drug discovery on membrane proteins.

    PubMed

    Wirmer-Bartoschek, Julia; Bartoschek, Stefan

    2012-05-01

    Drug discovery on membrane proteins is still a difficult task, despite the recognized importance of membrane proteins as drug targets. Here, we present an overview of NMR methods available for structure-based drug design on membrane proteins. NMR spectroscopy is capable of identifying potential binders in screening and defining their relative binding constants, binding stoichiometry, conformation in the binding pocket and the relative binding orientation for binders of different series. Examples are given in the review highlighting the potential of NMR spectroscopy for future progress in drug discovery on membrane proteins. PMID:22571612

  3. Probing porous media with gas diffusion NMR.

    PubMed

    Mair, R W; Wong, G P; Hoffmann, D; Hurlimann, M D; Patz, S; Schwartz, L M; Walsworth, R L

    1999-10-18

    We show that gas diffusion nuclear magnetic resonance (GD-NMR) provides a powerful technique for probing the structure of porous media. In random packs of glass beads, using both laser-polarized and thermally polarized xenon gas, we find that GD-NMR can accurately measure the pore space surface-area-to-volume ratio, S/V rho, and the tortuosity, alpha (the latter quantity being directly related to the system's transport properties). We also show that GD-NMR provides a good measure of the tortuosity of sandstone and complex carbonate rocks. PMID:11543587

  4. NMR logging and core analysis -- simplified

    SciTech Connect

    Murphy, D.P. [Shell E and P Co., Houston, TX (United States)

    1995-04-01

    This paper reviews the use of nuclear magnetic resonance (NMR) to determine various characteristics of oil and well stratigraphy and drill cores. NMR wireline logging tools, and benchtop spectrometer core and fluid analyzers can obtain information for formation evaluation decisions. All of this formation evaluation information cannot be obtained from NMR in every situation. Formation rock and fluid properties, and borehole environment affect accuracy and type of data that can be obtained. Information and performances is discussed on identifying: porosity, water saturation, permeability, fluid types, hydrocarbon types, oil saturation, and wettability information. The information is demonstrated in various graphs and a brief discussion of the types of logging tools are described.

  5. NMR investigations of gas transport in fluidized beds

    Microsoft Academic Search

    R. Wang; J. Ng; M. Rosen; R. Mair; R. Walsworth; D. Candela

    2004-01-01

    We are using NMR of hyperpolarized xenon to study gas transport in fluidized beds. Our preliminary investigations have shown that both the xenon NMR frequency and linewidth are dependent on the bulk gas flow rate through the bed; and that a distinct xenon NMR frequency spectral peak can be observed in the bubbling regime. These changes of the xenon NMR

  6. Development and Use of a Virtual NMR Facility

    Microsoft Academic Search

    Kelly A. Keating; James D. Myers; Jeffrey G. Pelton; Raymond A. Bair; David E. Wemmer; Paul D. Ellis

    2000-01-01

    We have developed a “virtual NMR facility” (VNMRF) to enhance access to the NMR spectrometers in Pacific Northwest National Laboratory's Environmental Molecular Sciences Laboratory (EMSL). We use the term virtual facility to describe a real NMR facility made accessible via the Internet. The VNMRF combines secure remote operation of the EMSL's NMR spectrometers over the Internet with real-time videoconferencing, remotely

  7. Development and Use of a Virtual NMR Facility

    Microsoft Academic Search

    Kelly A. Keating; James D. Myers; Jeffrey G. Pelton; Raymond A. Bair; David E. Wemmer; Paul D. Ellis

    2000-01-01

    We have developed a ``virtual NMR facility'' (VNMRF) to enhance access to the NMR spectrometers in Pacific Northwest National Laboratory's Environmental Molecular Sciences Laboratory (EMSL). We use the term virtual facility to describe a real NMR facility made accessible via the Internet. The VNMRF combines secure remote operation of the EMSL's NMR spectrometers over the Internet with real-time videoconferencing, remotely

  8. Quantum Theory of NMR Adiabatic Pulses and Their Applications

    Microsoft Academic Search

    Yong Ke

    1993-01-01

    Recently explosive developments of in vivo NMR spectroscopy (NMRS) and imaging (NMRI) in biological and medical sciences have resulted in the establishment of NMR as one of the most advanced major technique in life sciences. These developments have created huge demands for a variety of NMR adiabatic pulses with play a very important role in NMR experiments in vivo. In

  9. Quantitative determination of mebeverine HCl by NMR chemical shift migration

    Microsoft Academic Search

    Ian S. Blagbrough; Manal S. Elmasry; Timothy J. Woodman; Hanaa M. Saleh; Afaf Aboul Kheir

    2009-01-01

    Quantitative 1H NMR spectroscopic methods are not frequently reported, but current NMR instrumentation allows ready access to such data. Mebeverine HCl is an attractive molecule for NMR spectroscopy teaching purposes as it possesses a variety of simple but significant functional groups; we fully assign its 1H and 13C NMR spectra. Using mebeverine HCl, we show that concentration changes, in water

  10. The use of NMR core analysis in the interpretation of downhole NMR logs

    SciTech Connect

    Brancolini, A.; Gossenberg, P.; Lyne, A. [AGIP, Milano (Italy)] [and others

    1995-12-31

    Laboratory NMR measurements on core are particularly important for understanding NMR downhole logs from formations which have no NMR logging history. We have used low frequency (2MHz) NMR relaxation measurements on core plugs from a gas well in Southern Italy both to acquire petrophysical data and to clarify the interpretation of the downhole log. In the cored interval the lithology is divided into thin sand and shale beds (<1m). Measurements on the core have provided the basis for extracting maximum useful information from the NMR downhole measurements which do not resolve the thin beds. As part of a more general programme we have investigated the potential of NMR measurements on saturated core, from two wells in the field, as indirect predictors of other parameters of petrophysical interest such as irreducible water saturation and permeability.

  11. NMR Analysis of Unknowns: An Introduction to 2D NMR Spectroscopy

    ERIC Educational Resources Information Center

    Alonso, David E.; Warren, Steven E.

    2005-01-01

    A study combined 1D (one-dimensional) and 2D (two-dimensional) NMR spectroscopy to solve structural organic problems of three unknowns, which include 2-, 3-, and 4-heptanone. Results showed [to the first power]H NMR and [to the thirteenth power]C NMR signal assignments for 2- and 3-heptanone were more challenging than for 4-heptanone owing to the…

  12. NMR data visualization, processing, and analysis on mobile devices.

    PubMed

    Cobas, Carlos; Fernández, Isaac Iglesias; Otero, Felipe Seoane

    2015-08-01

    The design and technical development and capabilities of a new NMR app operating on both Android and iOS platforms to quickly visualize, process, analyze, and share NMR data on mobile devices, 'anywhere, anytime' are described. Routine 1D and 2D NMR spectra acquired in both high field and benchtop NMR instruments are fully supported. More advanced experiments such as non-uniform sampled NMR spectra can also be processed. PMID:26200331

  13. 33S NMR cryogenic probe for taurine detection

    NASA Astrophysics Data System (ADS)

    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 ?M taurine solutions, which is the level of sensitivity necessary for biological samples.

  14. Quantitative analysis of NMR spectra with chemometrics

    NASA Astrophysics Data System (ADS)

    Winning, H.; Larsen, F. H.; Bro, R.; Engelsen, S. B.

    2008-01-01

    The number of applications of chemometrics to series of NMR spectra is rapidly increasing due to an emerging interest for quantitative NMR spectroscopy e.g. in the pharmaceutical and food industries. This paper gives an analysis of advantages and limitations of applying the two most common chemometric procedures, Principal Component Analysis (PCA) and Multivariate Curve Resolution (MCR), to a designed set of 231 simple alcohol mixture (propanol, butanol and pentanol) 1H 400 MHz spectra. The study clearly demonstrates that the major advantage of chemometrics is the visualisation of larger data structures which adds a new exploratory dimension to NMR research. While robustness and powerful data visualisation and exploration are the main qualities of the PCA method, the study demonstrates that the bilinear MCR method is an even more powerful method for resolving pure component NMR spectra from mixtures when certain conditions are met.

  15. High-Pressure Protein Crystallography and NMR

    E-print Network

    Gruner, Sol M.

    High-Pressure Protein Crystallography and NMR to Explore Protein Conformations Marcus D. Collins,1 Crystallography. . . . . . . . . . . . . . . . . 87 Conformational Substates of Myglobin. . . . . . . . . . . . . . . . . . . . . . . 88 Energy Landscapes by Crystallography. . . . . . . . . . . . . . . . . 89 A VIEW INTO THE FUTURE

  16. Ab initio converse NMR approach for pseudopotentials

    E-print Network

    Ceresoli, Davide

    We extend the recently developed converse NMR approach [Thonhauser et al., J. Chem. Phys. 131, 101101 (2009)] such that it can be used in conjunction with norm-conserving, nonlocal pseudopotentials. This extension permits ...

  17. Modern NMR spectroscopy: a guide for chemists

    SciTech Connect

    Sanders, J.K.M.; Hunter, B.K.

    1988-01-01

    The aim of the authors of Modern NMR Spectroscopy is to bridge the communication gap between the chemist and the spectroscopist. The approach is nonmathematical, descriptive, and pictorial. To illustrate the ideas introduced in the text, the authors provide original spectra obtained specially for this purpose. Examples include spectroscopy of protons, carbon, and less receptive nuclei of interest to inorganic chemists. The authors succeed in making high-resolution NMR spectroscopy comprehensible for the average student or chemist.

  18. 2Dimensional NMR in Carbohydrate Structural Analysis

    Microsoft Academic Search

    Steven L. Patt

    1984-01-01

    2-Dimensional FT NMR techniques have greatly expanded the power of NMR to unravel complex chemical structures. Homonuclear 2D J-resolved experiments can be helpful in sorting out complex over lapping coupling patterns, while homonuclear chemical shift correla tion experiments can be used to determine the homonuclear coupling networks. Heteronuclear chemical shift correlation experiments can indicate the source of direct or long-range

  19. NMR Quantum Information Processing and Entanglement

    E-print Network

    Raymond Laflamme; David G. Cory; Camille Negrevergne; Lorenza Viola

    2001-10-05

    In this essay we discuss the issue of quantum information and recent nuclear magnetic resonance (NMR) experiments. We explain why these experiments should be regarded as quantum information processing (QIP) despite the fact that, in present liquid state NMR experiments, no entanglement is found. We comment on how these experiments contribute to the future of QIP and include a brief discussion on the origin of the power of quantum computers.

  20. Zero field NMR and NQR

    SciTech Connect

    Zax, D.B.; Bielecki, A.; Zilm, K.W.; Pines, A.; Weitekamp, D.P.

    1985-11-15

    Methods are described and demonstrated for detecting the coherent evolution of nuclear spin observables in zero magnetic field with the full sensitivity of high field NMR. The principle motivation is to provide a means of obtaining solid state spectra of the magnetic dipole and electric quadrupole interactions of disordered systems without the line broadening associated with random orientation with respect to the applied magnetic field. Comparison is made to previous frequency domain and high field methods. A general density operator formalism is given for the experiments where the evolution period is initiated by a sudden switching to zero field and is terminated by a sudden restoration of the field. Analytical expressions for the signals are given for a variety of simple dipolar and quadrupolar systems and numerical simulations are reported for up to six coupled spin-1/2 nuclei. Experimental results are reported or reviewed for /sup 1/H, /sup 2/D, /sup 7/Li, /sup 13/C, and /sup 27/Al nuclei in a variety of polycrystalline materials. The effects of molecular motion and bodily sample rotation are described. Various extensions of the method are discussed, including demagnetized initial conditions and correlation by two-dimensional Fourier transformation of zero field spectra with themselves or with high field spectra.

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

    ERIC Educational Resources Information Center

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

    2009-01-01

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

  2. Nuclear magnetic resonance apparatus having semitoroidal rf coil for use in topical NMR and NMR imaging

    DOEpatents

    Fukushima, Eiichi (Los Alamos, NM); Roeder, Stephen B. W. (La Mesa, CA); Assink, Roger A. (Albuquerque, NM); Gibson, Atholl A. V. (Bryan, TX)

    1986-01-01

    An improved nuclear magnetic resonance (NMR) apparatus for use in topical magnetic resonance (TMR) spectroscopy and other remote sensing NMR applications includes a semitoroidal radio-frequency (rf) coil. The semitoroidal rf coil produces an effective alternating magnetic field at a distance from the poles of the coil, so as to enable NMR measurements to be taken from selected regions inside an object, particularly including human and other living subjects. The semitoroidal rf coil is relatively insensitive to magnetic interference from metallic objects located behind the coil, thereby rendering the coil particularly suited for use in both conventional and superconducting NMR magnets. The semitoroidal NMR coil can be constructed so that it emits little or no excess rf electric field associated with the rf magnetic field, thus avoiding adverse effects due to dielectric heating of the sample or to any other interaction of the electric field with the sample.

  3. New NMR well logging/fracture mapping technique with possible application of SQUID NMR detection

    SciTech Connect

    Jackson, J.A.

    1981-01-01

    A new method for making NMR measurements has been developed that potentially can receive NMR signals from a precise distance into the geologic formation. It is based on the production of a toroidal region of homogeneous radial magnetic field near the mid-plane between two magnets arranged axially so their fields oppose between them. NMR signals have been detected from such a region in the laboratory. Preliminary data have been extrapolated to the projected performance of a logging tool using superconducting magnets. The presence of cryogenic temperatures required for these magnets may make signal detection using SQUIDs a logical consideration. Preliminary comparison of normal and SQUID NMR detection shows that near the borehole (<18 in.) standard NMR detection is probably superior; at greater distances SQUID detection may be advantageous. Directional detection of the signal may allow fractures near the wellbore to be mapped. Use of SQUID detection may be useful for this application.

  4. Sensitivity of nonuniform sampling NMR.

    PubMed

    Palmer, Melissa R; Suiter, Christopher L; Henry, Geneive E; Rovnyak, James; Hoch, Jeffrey C; Polenova, Tatyana; Rovnyak, David

    2015-06-01

    Many information-rich multidimensional experiments in nuclear magnetic resonance spectroscopy can benefit from a signal-to-noise ratio (SNR) enhancement of up to about 2-fold if a decaying signal in an indirect dimension is sampled with nonconsecutive increments, termed nonuniform sampling (NUS). This work provides formal theoretical results and applications to resolve major questions about the scope of the NUS enhancement. First, we introduce the NUS Sensitivity Theorem in which any decreasing sampling density applied to any exponentially decaying signal always results in higher sensitivity (SNR per square root of measurement time) than uniform sampling (US). Several cases will illustrate this theorem and show that even conservative applications of NUS improve sensitivity by useful amounts. Next, we turn to a serious limitation of uniform sampling: the SNR by US decreases for extending evolution times, and thus total experimental times, beyond 1.26T2 (T2 = signal decay constant). Thus, SNR and resolution cannot be simultaneously improved by extending US beyond 1.26T2. We find that NUS can eliminate this constraint, and we introduce the matched NUS SNR Theorem: an exponential sampling density matched to the signal decay always improves the SNR with additional evolution time. Though proved for a specific case, broader classes of NUS densities also improve SNR with evolution time. Applications of these theoretical results are given for a soluble plant natural product and a solid tripeptide (u-(13)C,(15)N-MLF). These formal results clearly demonstrate the inadequacies of applying US to decaying signals in indirect nD-NMR dimensions, supporting a broader adoption of NUS. PMID:25901905

  5. September, 2004 (Adapted from Michael Sattler's Lectures at EMBL Heidelberg) Introduction to biomolecular NMR spectroscopy

    E-print Network

    Ritort, Felix

    which can provide high-resolution structures of biological molecules such as proteins and nucleic acids ...................................................................................... 3 Methodological developments for structure determination by NMR ...........4 NMR in structural determination by solution NMR.....................................................14 NMR sample preparation

  6. NMR detection with an atomic magnetometer

    E-print Network

    Savukov, I M

    2004-01-01

    We demonstrate detection of NMR signals using a non-cryogenic atomic magnetometer and describe several novel applications of this technique. A water free induction decay (FID) signal in a 0.5 $\\mu$T field is detected using a spin-exchange-relaxation-free K magnetometer and the possibility of using a multi-channel magnetometer for 3-D MRI requiring only a single FID signal is described. We also demonstrate detection of less than $10^{13}$ $^{129}$Xe atoms whose NMR signal is enhanced by a factor of 540 due to Fermi-contact interaction with K atoms. This technique allows detection of less than $10^{9}$ $^{129}$Xe spins in a flowing system suitable for remote NMR applications.

  7. Wide-line NMR and protein hydration.

    PubMed

    Tompa, K; Bokor, M; Tompa, P

    2012-01-01

    In this chapter, the reader is introduced to the basics of wide-line NMR, with particular focus on the following: (1) basic theoretical and experimental NMR elements, necessary before switching the spectrometer and designing the experiment, (2) models/theories for the interpretation of measured data, (3) definition of wide-line NMR spectrometry, the description of the measurement and evaluation variants, useful hints for the novice, (4) advice on selecting the solvent, which is not a trivial task, (5) a note of warning that not all data are acceptable in spite of the statistical confidence. Finally, we wrap up the chapter with the results on two proteins (a globular and an intrinsically disordered). PMID:22760320

  8. T1? in Quadrupole-Perturbed NMR

    NASA Astrophysics Data System (ADS)

    Seliger, J.

    Spin-lattice relaxation time in the rotating frame, T1?, is calculated in quadrupole-perturbed NMR in the weak collision limit. It is assumed that the RF magnetic field excites only a single transition in the quadrupole-perturbed NMR spectrum. The results of the calculation show that T1?, associated with the central ( {1}/{2}?- {1}/{2}) transition in quadrupole-perturbed NMR of half-integer spin nuclei does not reflect the low-frequency fluctuations of the electric field-gradient tenser. On the other hand, the low-frequency fluctuations of the electric held-gradient tenser give the largest contribution to T1? when measured on the outer[± I?±( I-1)] satellite transitions.

  9. An optical NMR spectrometer for Larmor-beat detection and high-resolution POWER NMR

    NASA Astrophysics Data System (ADS)

    Kempf, J. G.; Marohn, J. A.; Carson, P. J.; Shykind, D. A.; Hwang, J. Y.; Miller, M. A.; Weitekamp, D. P.

    2008-06-01

    Optical nuclear magnetic resonance (ONMR) is a powerful probe of electronic properties in III-V semiconductors. Larmor-beat detection (LBD) is a sensitivity optimized, time-domain NMR version of optical detection based on the Hanle effect. Combining LBD ONMR with the line-narrowing method of POWER (perturbations observed with enhanced resolution) NMR further enables atomically detailed views of local electronic features in III-Vs. POWER NMR spectra display the distribution of resonance shifts or line splittings introduced by a perturbation, such as optical excitation or application of an electric field, that is synchronized with a NMR multiple-pulse time-suspension sequence. Meanwhile, ONMR provides the requisite sensitivity and spatial selectivity to isolate local signals within macroscopic samples. Optical NMR, LBD, and the POWER method each introduce unique demands on instrumentation. Here, we detail the design and implementation of our system, including cryogenic, optical, and radio-frequency components. The result is a flexible, low-cost system with important applications in semiconductor electronics and spin physics. We also demonstrate the performance of our systems with high-resolution ONMR spectra of an epitaxial AlGaAs /GaAs heterojunction. NMR linewidths down to 4.1Hz full width at half maximum were obtained, a 103-fold resolution enhancement relative any previous optically detected NMR experiment.

  10. Journal of Solid State Chemistry 180 (2007) 28772884 Cs4P2Se10: A new compound discovered with the application of

    E-print Network

    Weliky, David

    2007-01-01

    purity during a high-temperature synthesis done in a nuclear magnetic resonance (NMR) spectrometer. 31 P by quenching the melt in ice water, and Cs4P2Se10 was recovered upon annealing. The static 31 P NMR spectrum: NMR; Solid state; High temperature; Chalcogenides; Metal selenophosphates; Phosphorus; 31 P 1

  11. Hyperpolarized Xenon for NMR and MRI Applications

    PubMed Central

    Witte, Christopher; Kunth, Martin; Döpfert, Jörg; Rossella, Federica; Schröder, Leif

    2012-01-01

    Nuclear magnetic resonance (NMR) spectroscopy and imaging (MRI) suffer from intrinsic low sensitivity because even strong external magnetic fields of ~10 T generate only a small detectable net-magnetization of the sample at room temperature 1. Hence, most NMR and MRI applications rely on the detection of molecules at relative high concentration (e.g., water for imaging of biological tissue) or require excessive acquisition times. This limits our ability to exploit the very useful molecular specificity of NMR signals for many biochemical and medical applications. However, novel approaches have emerged in the past few years: Manipulation of the detected spin species prior to detection inside the NMR/MRI magnet can dramatically increase the magnetization and therefore allows detection of molecules at much lower concentration 2. Here, we present a method for polarization of a xenon gas mixture (2-5% Xe, 10% N2, He balance) in a compact setup with a ca. 16000-fold signal enhancement. Modern line-narrowed diode lasers allow efficient polarization 7 and immediate use of gas mixture even if the noble gas is not separated from the other components. The SEOP apparatus is explained and determination of the achieved spin polarization is demonstrated for performance control of the method. The hyperpolarized gas can be used for void space imaging, including gas flow imaging or diffusion studies at the interfaces with other materials 8,9. Moreover, the Xe NMR signal is extremely sensitive to its molecular environment 6. This enables the option to use it as an NMR/MRI contrast agent when dissolved in aqueous solution with functionalized molecular hosts that temporarily trap the gas 10,11. Direct detection and high-sensitivity indirect detection of such constructs is demonstrated in both spectroscopic and imaging mode. PMID:22986346

  12. An NMR Study of Microvoids in Polymers

    NASA Technical Reports Server (NTRS)

    Toy, James; Mattrix, Larry

    1996-01-01

    An understanding of polymer defect structures, like microvoids in polymeric matrices, is most crucial to their fabrication and application potential. In this project guest atoms are introduced into the microvoids in PMR-15 and NMR is used to determine microvoid sizes and locations. Xenon is a relatively inert probe that would normally not be found naturally in polymer or in NMR probe materials. There are two NMR active Xenon isotopes, Xe-129 and Xe-131. The Xe atom has a very high polarizability, which makes it sensitive to the intracrystalline environment of polymers. Interactions between the Xe atoms and the host matrix perturb and Xe electron cloud, deshielding the nuclei, and thereby expanding the range of the observed NMR chemical shifts. This chemical shift range which may be as large as 5000 ppm, permits subtle structural and chemical effects to be studied with high sensitivity. The Xe-129-NMR line shape has been found to vary in response to changes in the pore symmetry of the framework hosts in Zeolites and Clathrasil compounds. Before exposure to Xe gas, the PMR-15 samples were dried in a vacuum oven at 150 C for 48 hours. The samples were then exposed to Xe gas at 30 psi for 72 hours and sealed in glass tubes with 1 atmosphere of Xenon gas. Xenon gas at 1 atmosphere was used to tune up the spectrometer and to set up the appropriate NMR parameters. A series of spectra were obtained interspersed with applications of vacuum and heating to drive out the adsorbed Xe and determine the role of Xe-Xe interactions in the observed chemical shift.

  13. Hyperpolarized xenon for NMR and MRI applications.

    PubMed

    Witte, Christopher; Kunth, Martin; Döpfert, Jörg; Rossella, Federica; Schröder, Leif

    2012-01-01

    Nuclear magnetic resonance (NMR) spectroscopy and imaging (MRI) suffer from intrinsic low sensitivity because even strong external magnetic fields of ~10 T generate only a small detectable net-magnetization of the sample at room temperature (1). Hence, most NMR and MRI applications rely on the detection of molecules at relative high concentration (e.g., water for imaging of biological tissue) or require excessive acquisition times. This limits our ability to exploit the very useful molecular specificity of NMR signals for many biochemical and medical applications. However, novel approaches have emerged in the past few years: Manipulation of the detected spin species prior to detection inside the NMR/MRI magnet can dramatically increase the magnetization and therefore allows detection of molecules at much lower concentration (2). Here, we present a method for polarization of a xenon gas mixture (2-5% Xe, 10% N2, He balance) in a compact setup with a ca. 16000-fold signal enhancement. Modern line-narrowed diode lasers allow efficient polarization (7) and immediate use of gas mixture even if the noble gas is not separated from the other components. The SEOP apparatus is explained and determination of the achieved spin polarization is demonstrated for performance control of the method. The hyperpolarized gas can be used for void space imaging, including gas flow imaging or diffusion studies at the interfaces with other materials (8,9). Moreover, the Xe NMR signal is extremely sensitive to its molecular environment (6). This enables the option to use it as an NMR/MRI contrast agent when dissolved in aqueous solution with functionalized molecular hosts that temporarily trap the gas (10,11). Direct detection and high-sensitivity indirect detection of such constructs is demonstrated in both spectroscopic and imaging mode. PMID:22986346

  14. Prediction of peak overlap in NMR spectra.

    PubMed

    Hefke, Frederik; Schmucki, Roland; Güntert, Peter

    2013-06-01

    Peak overlap is one of the major factors complicating the analysis of biomolecular NMR spectra. We present a general method for predicting the extent of peak overlap in multidimensional NMR spectra and its validation using both, experimental data sets and Monte Carlo simulation. The method is based on knowledge of the magnetization transfer pathways of the NMR experiments and chemical shift statistics from the Biological Magnetic Resonance Data Bank. Assuming a normal distribution with characteristic mean value and standard deviation for the chemical shift of each observable atom, an analytic expression was derived for the expected overlap probability of the cross peaks. The analytical approach was verified to agree with the average peak overlap in a large number of individual peak lists simulated using the same chemical shift statistics. The method was applied to eight proteins, including an intrinsically disordered one, for which the prediction results could be compared with the actual overlap based on the experimentally measured chemical shifts. The extent of overlap predicted using only statistical chemical shift information was in good agreement with the overlap that was observed when the measured shifts were used in the virtual spectrum, except for the intrinsically disordered protein. Since the spectral complexity of a protein NMR spectrum is a crucial factor for protein structure determination, analytical overlap prediction can be used to identify potentially difficult proteins before conducting NMR experiments. Overlap predictions can be tailored to particular classes of proteins by preparing statistics from corresponding protein databases. The method is also suitable for optimizing recording parameters and labeling schemes for NMR experiments and improving the reliability of automated spectra analysis and protein structure determination. PMID:23585271

  15. NMR Stark Spectroscopy: New Methods to Calibrate NMR Sensitivity to Electric Fields

    NASA Astrophysics Data System (ADS)

    Tarasek, Matthew R.

    The influence of electrostatics on NMR parameters is well accepted. Thus, NMR is a promising route to probe electrical features within molecules and materials. However, applications of NMR Stark effects (E-field induced changes in spin energy levels) have been elusive. I have developed new approaches to resolve NMR Stark effects from an applied E field. This calibrates nuclear probes whose spectral response might later be used to evaluate internal E fields that are critical to function, such as those due to local charge distributions or sample structure. I will present two novel experimental approaches for direct calibration of NMR quadrupolar Stark effects (QSEs). In the first, steady-state (few-second) excitation by an E field at twice the NMR frequency (2? 0) is used to saturate spin magnetization. The extent of saturation vs. E-field amplitude calibrates the QSE response rate, while measurements vs sample orientation determine tensorial character. The second method instead synchronizes short (few µs) pulses of the 2?0 E field with a multiple-pulse NMR sequence. This, “POWER” (Perturbations Observed With Enhanced Resolution) approach enables more accurate measure of small QSEs (i.e. few Hz spectral changes). A 2nd key advantage is the ability to define tensorial response without reorienting the sample, but instead varying the phase of the 2?0 field. I will describe these experiments and my home-built NMR “Stark probe”, employed on a conventional wide-bore solid-state NMR system. Results with GaAs demonstrate each method, while extensions to a wider array of molecular and material systems may now be possible using these methods.

  16. AB Proton NMR Using Tensor Algebra Frank Rioux

    E-print Network

    Rioux, Frank

    AB Proton NMR Using Tensor Algebra Frank Rioux Professor Emeritus of Chemistry CSB|SJU The purpose of this tutorial is to deviate from the usual matrix mechanics approach to the ABC proton nmr system in order

  17. Rapid 3D MAS NMR Spectroscopy at Critical Sensitivity

    E-print Network

    Matsuki, Yoh

    Sensitive SIFTing: Multidimensional non-uniform sampling (NUS) NMR spectroscopy is extended to the severely sensitivity-limited regime typical of MAS NMR of biomacromolecules by the use of spectroscopy by the integration ...

  18. Journal of Biomolecular NMR, 15: 251264, 1999. KLUWER/ESCOM

    E-print Network

    Powers, Robert

    Journal of Biomolecular NMR, 15: 251­264, 1999. KLUWER/ESCOM © 1999 Kluwer Academic Publishers simulated and real protein NMR data sets. Abbreviations: CPU, central processing unit; CspA, the major cold

  19. The Montagne Ste Genevive Workshop on NMR of Biological Solids

    E-print Network

    enterocolitica adhesin A (YadA). In addition, solid-state NMR allowed us to gain information on the mobility NMR SPECTROSCOPY Actin plays a key role in muscle contraction. Even if the knowledge of the molecular

  20. (13)C NMR Metabolomics: INADEQUATE Network Analysis.

    PubMed

    Clendinen, Chaevien S; Pasquel, Christian; Ajredini, Ramadan; Edison, Arthur S

    2015-06-01

    The many advantages of (13)C NMR are often overshadowed by its intrinsically low sensitivity. Given that carbon makes up the backbone of most biologically relevant molecules, (13)C NMR offers a straightforward measurement of these compounds. Two-dimensional (13)C-(13)C correlation experiments like INADEQUATE (incredible natural abundance double quantum transfer experiment) are ideal for the structural elucidation of natural products and have great but untapped potential for metabolomics analysis. We demonstrate a new and semiautomated approach called INETA (INADEQUATE network analysis) for the untargeted analysis of INADEQUATE data sets using an in silico INADEQUATE database. We demonstrate this approach using isotopically labeled Caenorhabditis elegans mixtures. PMID:25932900

  1. Fourier transform zero field NMR and NQR

    SciTech Connect

    Zax, D.B.

    1984-09-01

    The characterization of the structural and chemical properties of matter, particularly in disordered condensed phases, is a difficult process. Few analytical methods work effectively on polycrystalline or amorphous solids. In many systems the chemical shifts measured by traditional high resolution solid state NMR methods are insufficiently sensitive or the information contained in the dipole-dipole couplings is more important. In these cases Fourier transform zero field magnetic resonance may make an important contribution. Zero field NMR and NQR is the subjecti of this thesis.

  2. NMR studies of laser-polarized xenon gas flow

    Microsoft Academic Search

    R. W. Mair; R. Wang; M. S. Rosen; R. L. Walsworth; D. Candela

    2003-01-01

    NMR techniques that are commonly used to measure diffusion can also be used to measure fluid velocity and\\/or acceleration. In recent years, laser-polarized noble gas NMR has developed into a powerful tool for spin density and diffusion imaging; however few attempts have been made to study gas flow by NMR. We report initial NMR velocity measurements of continuously flowing laser-polarized

  3. Applications of noble gas NMR to condensed matter systems

    Microsoft Academic Search

    C.-H. Tseng; R. W. Mair; G. P. Wong; R. L. Walsworth; S. Patz; D. Williamson; M. D. Hurlimann; L. M. Schwartz; D. G. Cory

    1998-01-01

    The spin-off of laser-polarized noble gases (^3He and ^129Xe) from atomic physics to biomedical imaging has renewed interest in gas-phase NMR and MRI. We are applying noble gas NMR to studies of condensed matter systems such as porous media and liquid xenon. NMR measurements of restricted noble gas diffusion in porous media offer two important advantages over conventional (liquid) NMR

  4. Advances of unilateral mobile NMR in nondestructive materials testing

    Microsoft Academic Search

    Bernhard Blümich; Federico Casanova; Juan Perlo; Sophia Anferova; Vladimir Anferov; Kai Kremer; Nicolae Goga; Klaus Kupferschläger; Michael Adams

    2005-01-01

    Unilateral mobile NMR employs portable instrumentation with sensors, which are applied to the object from one side. Based on the principles of well-logging NMR, a hand-held sensor, the NMR-MOUSE (MObile Universal Surface Explorer) has been developed for nondestructive materials testing. In the following, a number of new applications of unilateral NMR in materials science are reviewed. They are the state

  5. Two dimensional NMR and NMR relaxation studies on coal structure. Final report, September 13, 1994--January 31, 1995

    SciTech Connect

    Zilm, K.W.

    1995-10-01

    This research program focused on developing new solids nuclear magnetic resonance (NMR) techniques for improved analysis of coal structure. Most work has been concentrated on the development of spectral editing NMR methods for solids.

  6. NMR Structure of the Sea Urchin (Strongylocentrotus purpuratus) Metallothionein MTA

    E-print Network

    Riek, Roland

    NMR Structure of the Sea Urchin (Strongylocentrotus purpuratus) Metallothionein MTA Roland Riek1]-metallothionein-A (MTA) of the sea urchin Strongylocentrotus purpuratus was determined by homonuc- lear 1 H NMR Academic Press Keywords: metallothionein; NMR structure; sea urchin; metal-thiolate cluster topology

  7. Application of the NMR-MOUSE to food emulsions

    NASA Astrophysics Data System (ADS)

    Pedersen, H. T.; Ablett, S.; Martin, D. R.; Mallett, M. J. D.; Engelsen, S. B.

    2003-11-01

    The application of the NMR-MObile Universal Surface Explorer (NMR-MOUSE) to study food systems is evaluated using oil-in-water emulsions, and the results are compared to those obtained using a conventional low-field NMR (LF-NMR) instrument. The NMR-MOUSE is a small and portable LF-NMR system with a one-sided magnet layout that is used to replace the conventional magnet and probe on a LF-NMR instrument. The high magnetic field gradients associated with the one-sided MOUSE magnet result in NMR signal decays being dominated by molecular diffusion effects, which makes it possible to discriminate between the NMR signals from oil and water. Different data acquisition parameters as well as different approaches to the analysis of the NMR data from a range of oil-in-water emulsions are evaluated, and it is demonstrated how the concentration of oil and water can be determined from the NMR-MOUSE signals. From these model systems it is concluded that the NMR-MOUSE has good potential for the quantitative analysis of intact food products.

  8. Superoxygenated Water as an Experimental Sample for NMR Relaxometry

    ERIC Educational Resources Information Center

    Nestle, Nikolaus; Dakkouri, Marwan; Rauscher, Hubert

    2004-01-01

    The increase in NMR relaxation rates as a result of dissolved paramagnetic species on the sample of superoxygenated drinking water is demonstrated. It is concluded that oxygen content in NMR samples is an important issue and can give rise to various problems in the interpretation of both spectroscopic and NMR imaging or relaxation experiments.

  9. Artificial Neural Network Approach for NMR Data Analyses

    E-print Network

    Schouten, Theo

    : : : : : : : : : : : : : : : : : : : : : : : : : : 25 3.7.2 13 C NMR : : : : : : : : : : : : : : : : : : : : : : : : : 26 3.7.3 31 P NMR 3.1 Meaning of a NMR­Spectrum : : : : : : : : : : : : : : : : : : 19 3.2 The Fourier TransformArtificial Neural Network Approach for NMR Data Analyses E.R. de Blouw (9102337) Master Thesis no

  10. Applications of Diffusion Ordered Spectroscopy (DOSY-NMR)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Diffusion-ordered NMR (DOSY-NMR) is a powerful, but under-utilized, technique for the investigation of mixtures based on translational diffusion rates. DOSY spectra allow for determination by NMR of components that may differ in molecular weight, geometry or complexation. Typical applications coul...

  11. Low Field dc SQUID NMR on Room Temperature Samples

    E-print Network

    Sheldon, Nathan D.

    Low Field dc SQUID NMR on Room Temperature Samples and Single Crystal UPt3 by Aya Shibahara is the technique of dc SQUID NMR. Firstly the application of the technique for broadband spectroscopy on room temperature samples is described. The mo- tivation behind this work was to try to obtain SQUID NMR signals

  12. Solid state NMR measurements of conformation and conformational

    E-print Network

    Weliky, David

    Solid state NMR measurements of conformation and conformational distributions in the membrane Lansing, MI, USA The solid state NMR lineshape of a protein backbone carbonyl nucleus is a general conformation in the distri- bution. These types of solid state NMR methodologies have been applied

  13. The Muon g-2 Experiment The NMR Probe Circuitry

    E-print Network

    Washington at Seattle, University of - Department of Physics, Electroweak Interaction Research Group

    The Muon g-2 Experiment The NMR Probe Circuitry Upgrading the Circuit Building the Circuit Future Work Updating NMR Probe Electronics in the Muon g-2 Experiment Audrey Kvam University of Washington September 1, 2014 Audrey Kvam Updating NMR Probe Electronics in the Muon g-2 Experiment #12;The Muon g-2

  14. A New Unfree Fluid Index in Sandstones Through NMR Studies

    Microsoft Academic Search

    G. C. Borgia

    1996-01-01

    Nuclear magnetic resonance (NMR) of ¹H nuclei of liquids in saturated porous rocks furnishes an increasingly important tool in core analysis as well as in well-logging. In particular, there are several basic questions regarding NMR downhole logging in reservoir sandstones. For this reason, it is of interest to investigate the laboratory NMR properties to identify some important basic mechanisms. This

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

    Microsoft Academic Search

    George J. Hirasaki; Kishore K. Mohanty

    2005-01-01

    The objective of this report is to characterize the fluid properties and fluid-rock interactions that are needed for formation evaluation by NMR well logging. The advances made in the understanding of NMR fluid properties are summarized in a chapter written for an AAPG book on NMR well logging. This includes live oils, viscous oils, natural gas mixtures, and the relation

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

    Microsoft Academic Search

    George J. Hirasaki; Kishore K. Mohanty

    2003-01-01

    The objective of this project was to characterize the fluid properties and fluid-rock interactions that are needed for formation evaluation by NMR well logging. The advances made in the understanding of NMR fluid properties are summarized in a chapter written for an AAPG book on NMR well logging. This includes live oils, viscous oils, natural gas mixtures, and the relation

  17. The use of spectroscopic techniques (especially phosphorus-31 nuclear magnetic resonance [31

    E-print Network

    Sparks, Donald L.

    P species. Although phosphate associated with calcium and aluminum made up a large proportion of P forms of P in manures, identifying them as mostly calcium phosphate phases, phosphate associated controlled conditions. The magnesium ammonium phosphate mineral struvite was identified in all but one PL

  18. In vivo 19F NMR imaging.

    PubMed

    McFarland, E; Koutcher, J A; Rosen, B R; Teicher, B; Brady, T J

    1985-01-01

    In vitro and in vivo 19F spectra and images were obtained using various clinically safe fluorinated compounds. Standard and chemical shift images were acquired in solutions of fluorinated anesthetics with the chemical shift images clearly separating signals arising from a mixture of halothane and methoxyflurane. The 19F images of halothane in rats were unsuccessful at anesthetic concentration. In vivo 19F nuclear magnetic resonance (NMR) images were acquired at 57.9 MHz in rats receiving chronic injections of 14% perfluorodecalin, 6% perfluorotripropylamine (Fluosol-DA). The liver accumulates Fluosol-DA in the reticuloendothelial cells to concentrations that allow images to be obtained in less than 30 min. Image intensity from the perfluorochemicals reflects reticuloendothelial cell activity and thus is a functional image. Conventional proton NMR images at corresponding levels confirmed that the 19F signal arose from the liver and not muscle or fat. The 19F NMR images of the large bowel and stomach in rats were obtained by filling the lumen with concentrated Fluosol-DA. High contrast anatomical images showing gross structure of the gastrointestinal tract were acquired in as little as 12 min. These data suggest that 19F NMR may have a potential role in clinical imaging. PMID:3968284

  19. NMR implantable probe: limit of metabolites detection

    Microsoft Academic Search

    N. Baxan; J. F. Châteaux; A. Rengle; H. Rabeson; A. Briguet; G. Pasquet; P. Morin

    In this study a new concept of micro coil is presented in order to measure the small volumes and small concentrations samples by NMR spectroscopy. The goal of our work is to determine the concentration sensitivity and the limit of detection of a planar microcoil of ellipsoidal geometry 1000 x 500 ?m, fabricated using an electro plating technique and used

  20. Fourier transform zero field NMR and NQR

    SciTech Connect

    Zax, D.B.

    1985-01-01

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

  1. NMR Studies of Metallointercalator-DNA Interactions

    NASA Astrophysics Data System (ADS)

    Buck, Damian P.; Collins, J. Grant

    The study of the interaction between inert transition metal complexes and nucleic acids has developed from the early work of Dwyer [1], Lippard [2], Nordén [3] and Barton [4] to the point that it is now a central theme in bio-inorganic chemistry. While there has been considerable interest in metal complexes that bind nucleic acids, the interaction of metallointercalators with DNA and RNA has received the most attention [5, 6]. Square-planar platinum(II) complexes have demonstrated significant anticancer activity [7], and octahedral ruthenium(II) and rhodium(III) complexes have been used as probes of nucleic acid structure and as a means to study electron transfer reactions mediated by the heteroaromatic bases [5, 6]. While a range of techniques is available to study the nucleic acid binding of metal complexes, NMR spectroscopy (particularly 1H NMR) has proven to be the most useful. NMR spectroscopy can provide a detailed, atom level resolution, picture of the metal complex binding, and if the quality of the data is sufficient, a threedimensional structure of the metal complex bound to the oligonucleotide can be determined. The strategies used to assign the 1H NMR spectrum of an oligonucleotide [8-10], the extension of these methods to study the interaction of metal complexes with DNA and the use of molecular modelling will be presented in this chapter.

  2. Solid-state NMR imaging system

    DOEpatents

    Gopalsami, Nachappa (Naperville, IL); Dieckman, Stephen L. (Elmhurst, IL); Ellingson, William A. (Naperville, IL)

    1992-01-01

    An apparatus for use with a solid-state NMR spectrometer includes a special imaging probe with linear, high-field strength gradient fields and high-power broadband RF coils using a back projection method for data acquisition and image reconstruction, and a real-time pulse programmer adaptable for use by a conventional computer for complex high speed pulse sequences.

  3. NMR structure of the bovine prion protein

    Microsoft Academic Search

    Francisco López García; Ralph Zahn; Roland Riek; Kurt Wüthrich

    2000-01-01

    The NMR structures of the recombinant 217-residue polypeptide chain of the mature bovine prion protein, bPrP(23-230), and a C-terminal fragment, bPrP(121-230), include a globular domain extending from residue 125 to residue 227, a short flexible chain end of residues 228-230, and an N-terminal flexibly disordered \\

  4. Molecular Structure and Dynamics by NMR Spectroscopy

    NSDL National Science Digital Library

    Edison, Arthur S.

    This site provides PowerPoint slides for a lecture for a graduate-level course in NMR spectroscopy. The slides include useful animations which help to demonstrate the concepts described. While the casual student may find it hard to follow everything on the slides without an accompanying lecture, the files should be very useful for advanced students or educators putting together similar courses.

  5. SQUID detected NMR in microtesla magnetic fields

    NASA Astrophysics Data System (ADS)

    Matlachov, Andrei N.; Volegov, Petr L.; Espy, Michelle A.; George, John S.; Kraus, Robert H.

    2004-09-01

    We have built an NMR system that employs a superconducting quantum interference device (SQUID) detector and operates in measurement fields of 2-25 ?T. The system uses a pre-polarizing field from 4 to 30 mT generated by simple room-temperature wire-wound coils that are turned off during measurements. The instrument has an open geometry with samples located outside the cryostat at room-temperature. This removes constraints on sample size and allows us to obtain signals from living tissue. We have obtained 1H NMR spectra from a variety of samples including water, mineral oil, and a live frog. We also acquired gradient encoded free induction decay (FID) data from a water-plastic phantom in the ?T regime, from which simple projection images were reconstructed. NMR signals from samples inside metallic containers have also been acquired. This is possible because the penetration skin depth is much greater at the low operating frequencies of this system than for conventional systems. Advantages to ultra-low field NMR measurements include lower susceptibility artifacts caused by high strength polarizing and measurement fields, and negligible line width broadening due to measurement field inhomogeneity, reducing the burden of producing highly homogeneous fields.

  6. NMR measurement of bitumen at different temperatures

    Microsoft Academic Search

    Zheng Yang; George J. Hirasaki

    2008-01-01

    Heavy oil (bitumen) is characterized by its high viscosity and density, which is a major obstacle to both well logging and recovery. Due to the lost information of T2 relaxation time shorter than echo spacing (TE) and interference of water signal, estimation of heavy oil properties from NMR T2 measurements is usually problematic. In this work, a new method has

  7. Laplace Inversion of Low-Resolution NMR

    E-print Network

    Stanford University

    in industrial quality control for the deter- mination of solid-to-liquid and oil-to-water ratios in materials of digital images and signals. In this article, a numerical optimization method for analyzing LR- NMR data as diverse as oil-bearing rock, food emul- sions, and plant seeds (1). It offers great potential

  8. OPENCORE NMR: Open-source core modules for implementing an integrated FPGA-based NMR spectrometer

    Microsoft Academic Search

    Kazuyuki Takeda

    2008-01-01

    A tool kit for implementing an integrated FPGA-based NMR spectrometer [K. Takeda, A highly integrated FPGA-based nuclear magnetic resonance spectrometer, Rev. Sci. Instrum. 78 (2007) 033103], referred to as the OPENCORE NMR spectrometer, is open to public. The system is composed of an FPGA chip and several peripheral boards for USB communication, direct-digital synthesis (DDS), RF transmission, signal acquisition, etc.

  9. An NMR study of microvoids in polymers

    NASA Technical Reports Server (NTRS)

    Toy, James; Mattix, Larry

    1995-01-01

    An understanding of polymer defect structures, like microvoids in polymeric matrices, is crucial to their fabrication and application potential. In this project guest atoms are introduced into the microvoids in PMR-15 and NMR is used to determine microvoid sizes and locations. Xenon is a relatively inert probe that would normally be found naturally in polymer or in NMR probe materials. There are two NMR active xenon isotopes, Xe-129 and Xe-131. The Xe atom has a very high polarizability, which makes it sensitive to the intracrystalline environment of polymers. Interactions between the Xe atoms and the host matrix perturb the Xe electron cloud, deshielding the nuclei, and thereby expanding the range of the observed NMR chemical shifts. This chemical shift range which may be as large as 5000 ppm, permits subtle structural and chemical effects to be studied with high sensitivity. The Xe(129)-NMR line shape has been found to vary in response to changes in the pore symmetry of the framework hosts line Zeolites and Clathrasil compounds. Before exposure to Xe gas, the PMR-15 samples were dried in a vacuum oven at 150 C for 48 hours. The samples were then exposed to Xe gas at 30 psi for 72 hours and sealed in glass tubes with 1 atmosphere of xenon gas. Xenon gas at 1 atmosphere was used to tune up the spectrometer and to set up the appropriate NMR parameters. A single Xe-129 line at 83.003498 Mhz (with protons at 300 Mhz) was observed for the gas. With the xenon charged PMR-15 samples, a second broader line is observed 190 ppm downfield from the gas line (also observed). The width of the NMR line from the Xe-129 absorbed in the polymer is at least partially due to the distribution of microvoid sizes. From the chemical shift (relative to the gas line) and the line width, we estimate the average void sizes to be 2.74 +/- 0.20 angstroms. Since Xe-129 has such a large chemical shift range (approximately 5000 ppm), we expect the chemical shift anisotropy to contribute to the line width (delta upsilon = 2.5 kHz).

  10. Squid detected NMR and MRI at ultralow fields

    DOEpatents

    Clarke, John (Berkeley, CA); Pines, Alexander (Berkeley, CA); McDermott, Robert F. (Monona, WI); Trabesinger, Andreas H. (London, GB)

    2008-12-16

    Nuclear magnetic resonance (NMR) signals are detected in microtesla fields. Prepolarization in millitesla fields is followed by detection with an untuned dc superconducting quantum interference device (SQUID) magnetometer. Because the sensitivity of the SQUID is frequency independent, both signal-to-noise ratio (SNR) and spectral resolution are enhanced by detecting the NMR signal in extremely low magnetic fields, where the NMR lines become very narrow even for grossly inhomogeneous measurement fields. MRI in ultralow magnetic field is based on the NMR at ultralow fields. Gradient magnetic fields are applied, and images are constructed from the detected NMR signals.

  11. Squid detected NMR and MRI at ultralow fields

    DOEpatents

    Clarke, John (Berkeley, CA); McDermott, Robert (Louisville, CO); Pines, Alexander (Berkeley, CA); Trabesinger, Andreas Heinz (CH-8006 Zurich, CH)

    2007-05-15

    Nuclear magnetic resonance (NMR) signals are detected in microtesla fields. Prepolarization in millitesla fields is followed by detection with an untuned dc superconducting quantum interference device (SQUID) magnetometer. Because the sensitivity of the SQUID is frequency independent, both signal-to-noise ratio (SNR) and spectral resolution are enhanced by detecting the NMR signal in extremely low magnetic fields, where the NMR lines become very narrow even for grossly inhomogeneous measurement fields. MRI in ultralow magnetic field is based on the NMR at ultralow fields. Gradient magnetic fields are applied, and images are constructed from the detected NMR signals.

  12. Sodium ion effect on silk fibroin conformation characterized by solid-state NMR and generalized 2D NMR–NMR correlation

    Microsoft Academic Search

    Qing-Xia Ruan; Ping Zhou

    2008-01-01

    In the present work, we investigated Na+ ion effect on the silk fibroin (SF) conformation. Samples are Na+-involved regenerated silk fibroin films. 13C CP-MAS NMR demonstrates that as added [Na+] increases, partial silk fibroin conformation transit from helix-form to ?-form at certain Na+ ion concentration which is much higher than that in Bombyx mori silkworm gland. The generalized two-dimensional NMR–NMR

  13. Multiecho scheme advances surface NMR for aquifer characterization

    NASA Astrophysics Data System (ADS)

    Grunewald, Elliot; Walsh, David

    2013-12-01

    nuclear magnetic resonance (NMR) is increasingly used as a method to noninvasively characterize aquifers. This technology follows a successful history of NMR logging, applied over decades to estimate hydrocarbon reservoir properties. In contrast to logging, however, surface methods have utilized relatively simple acquisition sequences, from which pore-scale properties may not be reliably and efficiently estimated. We demonstrate for the first time the capability of sophisticated multiecho measurements to rapidly record a surface NMR response that more directly reflects aquifer characteristics. Specifically, we develop an adaptation of the multipulse Carr-Purcell-Meiboom-Gill (CPMG) sequence, widely used in logging, to measure the T2 relaxation response in a single scan. We validate this approach in a field surface NMR data set and by direct comparison with an NMR log. Adoption of the CPMG marked a landmark advancement in the history of logging NMR; we have now realized this same advancement in the surface NMR method.

  14. NMR CHARACTERIZATIONS OF PROPERTIES OF HETEROGENEOUS MEDIA

    SciTech Connect

    C.T. Philip Chang; Changho Choi; Jeromy T. Hollenshead; Rudi Michalak; Jack Phan; Ramon Saavedra; John C. Slattery; Jinsoo Uh; Randi Valestrand; A. Ted Watson; Song Xue

    2005-01-01

    A critical and long-standing need within the petroleum industry is the specification of suitable petrophysical properties for mathematical simulation of fluid flow in petroleum reservoirs (i.e., reservoir characterization). The development of accurate reservoir characterizations is extremely challenging. Property variations may be described on many scales, and the information available from measurements reflect different scales. In fact, experiments on laboratory core samples, well-log data, well-test data, and reservoir-production data all represent information potentially valuable to reservoir characterization, yet they all reflect information about spatial variations of properties at different scales. Nuclear magnetic resonance (NMR) spectroscopy and imaging (MRI) provide enormous potential for developing new descriptions and understandings of heterogeneous media. NMR has the rare capability to probe permeable media non-invasively, with spatial resolution, and it provides unique information about molecular motions and interactions that are sensitive to morphology. NMR well-logging provides the best opportunity ever to resolve permeability distributions within petroleum reservoirs. We develop MRI methods to determine, for the first time, spatially resolved distributions of porosity and permeability within permeable media samples that approach the intrinsic scale: the finest resolution of these macroscopic properties possible. To our knowledge, this is the first time that the permeability is actually resolved at a scale smaller than the sample. In order to do this, we have developed a robust method to determine of relaxation distributions from NMR experiments and a novel implementation and analysis of MRI experiments to determine the amount of fluid corresponding to imaging regions, which are in turn used to determine porosity and saturation distributions. We have developed a novel MRI experiment to determine velocity distributions within flowing experiments, and developed methodology using that data to determine spatially resolved permeability distributions. We investigate the use of intrinsic properties for developing improved correlations for predicting permeability from NMR well-logging data and for obtaining more accurate estimates of multiphase flow properties--the relative permeability and capillary pressure--from displacement experiments. We demonstrate the use of MRI measurements of saturation and relaxation for prediction wetting-phase relative permeability for unstable experiments. Finally, we developed an improved method for determining surface relaxivity with NMR experiments, which can provide better descriptions of permeable media microstructures and improved correlations for permeability predictions.

  15. BODIPY chromophores as efficient green light sensitizers for lanthanide-induced near-infrared emission.

    PubMed

    Zhong, Yihan; Si, Liping; He, Hongshan; Sykes, Andrew G

    2011-11-21

    A new boron dipyrromethene (BODIPY) modified 8-hydroxylquinoline ligand (8-HOQ-BODIPY) is synthesized for the sensitization of near-infrared emission of lanthanide(III) ions. The BODIPY unit, as revealed by single-crystal X-ray diffraction analysis, aligns almost perpendicularly to the 8-HOQ unit. The ligand exhibits strong absorption at ~506 nm and fluorescence at 510 nm in organic solvents with quantum yields ranging from ~0.45 in dichloromethane to 0.015 in ethanol. It forms stable ytterbium(III), erbium(III) and neodymium(III) complexes with 3:1 ligand-to-metal molar ratios. Upon excitation (~522 nm), the neodymium(III) and erbium(III) complexes emit weakly at 1060 and 1382 nm, respectively, whereas the ytterbium(III) complex exhibits strong emission at 976 and 1003 nm. The results demonstrate the potential of BODIPY dyes as efficient and robust visible light sensitizers for lanthanide-based NIR emitters in medical diagnosis. PMID:21922080

  16. Sodium ion effect on silk fibroin conformation characterized by solid-state NMR and generalized 2D NMR NMR correlation

    NASA Astrophysics Data System (ADS)

    Ruan, Qing-Xia; Zhou, Ping

    2008-07-01

    In the present work, we investigated Na + ion effect on the silk fibroin (SF) conformation. Samples are Na +-involved regenerated silk fibroin films. 13C CP-MAS NMR demonstrates that as added [Na +] increases, partial silk fibroin conformation transit from helix-form to ?-form at certain Na + ion concentration which is much higher than that in Bombyx mori silkworm gland. The generalized two-dimensional NMR-NMR correlation analysis reveals that silk fibroin undergoes several intermediate states during its conformation transition process as [Na +] increase. The appearance order of the intermediates is followed as: helix and/or random coil ? helix-like ? ?-sheet-like ? ?-sheet, which is the same as that produced by pH decrease from 6.8 to 4.8 in the resultant regenerated silk fibroin films. The binding sites of Na + to silk fibroin might involve the carbonyl oxygen atom of certain amino acids sequence which could promote the formation of ?-sheet conformation. Since the Na +sbnd O bond is weak, the ability of Na + inducing the secondary structure transition is weaker than those of Ca 2+, Cu 2+ and even K +. It is maybe a reason why the sodium content is much lower than potassium in the silkworm gland.

  17. NMR studies of nucleic acid dynamics

    PubMed Central

    Al-Hashimi, Hashim M.

    2014-01-01

    Nucleic acid structures have to satisfy two diametrically opposite requirements; on one hand they have to adopt well-defined 3D structures that can be specifically recognized by proteins; on the other hand, their structures must be sufficiently flexible to undergo very large conformational changes that are required during key biochemical processes, including replication, transcription, and translation. How do nucleic acids introduce flexibility into their 3D structure without losing biological specificity? Here, I describe the development and application of NMR spectroscopic techniques in my laboratory for characterizing the dynamic properties of nucleic acids that tightly integrate a broad set of NMR measurements, including residual dipolar couplings, spin relaxation, and relaxation dispersion with sample engineering and computational approaches. This approach allowed us to obtain fundamental new insights into directional flexibility in nucleic acids that enable their structures to change in a very specific functional manner. PMID:24149218

  18. (129)Xe NMR of Mesoporous Silicas

    SciTech Connect

    Anderson, M.T.; Asink, R.A.; Kneller, J.M.; Pietrass, T.

    1999-04-23

    The porosities of three mesoporous silica materials were characterized with {sup 129}Xe NMR spectroscopy. The materials were synthesized by a sol-gel process with r = 0, 25, and 70% methanol by weight in an aqueous cetyltrimethylammonium bromide solution. Temperature dependent chemical shifts and spin lattice relaxation times reveal that xenon does not penetrate the pores of the largely disordered (r= 70%) silica. For both r = 0 and 25%, temperature dependent resonances corresponding to physisorbed xenon were observed. An additional resonance for the r = 25% sample was attributed to xenon between the disordered cylindrical pores. 2D NMR exchange experiments corroborate the spin lattice relaxation data which show that xenon is in rapid exchange between the adsorbed and the gas phase.

  19. Nuclear spin noise in NMR revisited

    E-print Network

    Ferrand, Guillaume; Luong, Michel; Desvaux, Hervé

    2015-01-01

    The theoretical shapes of nuclear spin-noise spectra in NMR are derived by considering a receiver circuit with finite, preamplifier input impedance and a transmission line between the preamplifier and the probe. Using this model, it becomes possible to reproduce all observed experimental features: variation of the NMR resonance linewidth as a function of the transmission line phase, nuclear spin-noise signals appearing as a "bump" or as a "dip" superimposed on the average electronic noise level even for a spin system and probe at the same temperature, pure in-phase Lorentzian spin-noise signals exhibiting non-vanishing frequency shifts. Extensive comparison to experimental measurements validate the model predictions, and define the conditions for obtaining pure in-phase Lorentzian-shape nuclear spin noise with a vanishing frequency shift, in other words, the conditions for simultaneously obtaining the Spin-Noise and Frequency-Shift Tuning Optima.

  20. NMR Quantum Calculations of the Jones Polynomial

    E-print Network

    Raimund Marx; Amr Fahmy; Louis Kauffman; Samuel Lomonaco; Andreas Spörl; Nikolas Pomplun; John Myers; Steffen J. Glaser

    2009-09-06

    The repertoire of problems theoretically solvable by a quantum computer recently expanded to include the approximate evaluation of knot invariants, specifically the Jones polynomial. The experimental implementation of this evaluation, however, involves many known experimental challenges. Here we present experimental results for a small-scale approximate evaluation of the Jones Polynomial by nuclear-magnetic resonance (NMR), in addition we show how to escape from the limitations of NMR approaches that employ pseudo pure states. Specifically, we use two spin 1/2 nuclei of natural abundance chloroform and apply a sequence of unitary transforms representing the Trefoil Knot, the Figure Eight Knot and the Borromean Rings. After measuring the state of the molecule in each case, we are able to estimate the value of the Jones Polynomial for each of the knots.

  1. Superconducting wires for NMR-application

    SciTech Connect

    Salunin, N.I.; Plashkin, E.I.; Nikulenkov, E.V. [Bochvar All-Russia Scientific Research Inst. of Inorganic Materials, Moscow (Russian Federation)] [and others] [Bochvar All-Russia Scientific Research Inst. of Inorganic Materials, Moscow (Russian Federation); and others

    1996-07-01

    NMR analytical systems and MRI imaging magnets are now the very important area of NbTi based superconductors application. The characteristic features of these magnet systems are stability and high homogeneity of magnet fields. That is why the requirements for superconductors for that application include long unit length, low packing factor (P.F.) of superconducting alloy, high conductivity of matrix, precise dimensions of the filaments and the wire as a whole. Here, the results are presented on production of NbTi based conductors in copper matrix with wire diameters from 0.8 to 1.75 mm, filament numbers 12--42, filament diameters 55--130 {micro}m and packing factors 6.5--23%, with application in various NMR and MRI magnet systems. It is shown, that wire length could be tens of kilometers. Critical current, RRR and dielectric strength in all cases exceed requirements.

  2. Zero-field NMR and NQR spectrometer

    SciTech Connect

    Bielecki, A.; Zax, D.B.; Zilm, K.W.; Pines, A.

    1986-03-01

    In comparison to high-field NMR, zero-field techniques offer advantages in terms of spectral interpretability in studies of polycrystalline or amorphous solids. This article describes a technique and apparatus for time-domain measurements of nuclear magnetism in the absence of applied fields (Fourier transform zero-field NMR and NQR). Magnetic field cycling and high field detection are employed to enhance sensitivity. The field cycling is accomplished with an air-driven shuttle system which moves the sample between regions of high and low magnetic field, in combination with switchable electromagnets in the low-field region. Sudden field steps or pulses are used to initiate coherent nuclear spin evolution in zero field and to monitor such evolution as a function of time. Experimental results are shown and analyzed. Possible variations on the basic method are described and their relative advantages are discussed.

  3. Some nitrogen-14 NMR studies in solids

    SciTech Connect

    Pratum, T.K.

    1983-11-01

    The first order quadrupolar perturbation of the /sup 14/N NMR spectrum yields information regarding the static and dynamic properties of the surrounding electronic environment. Signal to noise problems caused by long /sup 14/N longitudinal relaxation times (T/sub 1/) and small equilibrium polarizations are reduced by rotating frame cross polarization (CP) experiments between /sup 14/N and /sup 1/H. Using quadrupolar echo and CP techniques, the /sup 14/N quadrupolar coupling constants (e/sup 2/qQ/h) and asymmetry parameters (eta) have been obtained for a variety of tetraalkylammonium compounds by observation of their quadrupolar powder patterns at various temperatures. For choline chloride and iodide the /sup 14/N NMR powder patterns exhibit the effects of anisotropic molecular motion, while choline bromide spectra show no such effects.

  4. Protein Structure Determination Using Protein Threading and Sparse NMR Data

    SciTech Connect

    Crawford, O.H.; Einstein, J.R.; Xu, D.; Xu, Y.

    1999-11-14

    It is well known that the NMR method for protein structure determination applies to small proteins and that its effectiveness decreases very rapidly as the molecular weight increases beyond about 30 kD. We have recently developed a method for protein structure determination that can fully utilize partial NMR data as calculation constraints. The core of the method is a threading algorithm that guarantees to find a globally optimal alignment between a query sequence and a template structure, under distance constraints specified by NMR/NOE data. Our preliminary tests have demonstrated that a small number of NMR/NOE distance restraints can significantly improve threading performance in both fold recognition and threading-alignment accuracy, and can possibly extend threading's scope of applicability from structural homologs to structural analogs. An accurate backbone structure generated by NMR-constrained threading can then provide a significant amount of structural information, equivalent to that provided by the NMR method with many NMR/NOE restraints; and hence can greatly reduce the amount of NMR data typically required for accurate structure determination. Our preliminary study suggests that a small number of NMR/NOE restraints may suffice to determine adequately the all-atom structure when those restraints are incorporated in a procedure combining threading, modeling of loops and sidechains, and molecular dynamics simulation. Potentially, this new technique can expand NMR's capability to larger proteins.

  5. Development of Halbach magnet for portable NMR device

    NASA Astrophysics Data System (ADS)

    Do?an, N.; Topkaya, R.; Suba?i, H.; Yerli, Y.; Rameev, B.

    2009-03-01

    Nuclear magnetic resonance (NMR) has enormous potential for various applications in industry as the on-line or at-line test/control device of process environments. Advantage of NMR is its non-destructive nature, because it does not require the measurement probe to have a contact with the tested media. Despite of the recent progress in this direction, application of NMR in industry is still very limited. This is related to the technical and analytical complications of NMR as a method, and high cost of NMR analyzers available at the market. However in many applications, NMR is a very useful technique to test various products and to monitor quantitatively industrial processes. Fortunately usually there is no need in a high-field superconducting magnets to obtain the high-resolution spectra with the detailed information on chemical shifts and coupling-constant. NMR analyzers are designed to obtain the relaxation parameters by measuring the NMR spectra in the time domain rather than in frequency domain. Therefore it is possible to use small magnetic field (and low frequency of 2-60 MHz) in NMR systems, based on permanent magnet technology, which are specially designed for specific at-line and on-line process applications. In this work we present the permanent magnet system developed to use in the portative NMR devices. We discuss the experimental parameters of the designed Halbach magnet system and compare them with results of theoretical modelling.

  6. Highly flexible pulse programmer for NMR applications

    NASA Technical Reports Server (NTRS)

    Dart, J.; Burum, D. P.; Rhim, W. K.

    1980-01-01

    A pulse generator for NMR application is described. Eighteen output channels are provided to allow use in single and double resonance experiments. Complex pulse sequences may be generated by loading instructions into a 256-word by 16-bit program memory. Features of the pulse generator include programmable time delays from 0.5 micros to 1000 s, branching and looping instructions, and the ability to be loaded and operated either manually or from a PDP-11/10 computer.

  7. Developments in core analysis by NMR measurements

    Microsoft Academic Search

    G. C. Borgia; V. Bortolotti; A. Brancolini; R. J. S. Brown; P. Fantazzini

    1996-01-01

    For a large suite of consolidated sandstone samples low in shale content we have measured the permeability k, irreducible water saturation Swi, porosity ?, electrical-resistivity formation factor F, porosity by NMR, geometric-mean relaxation times T1g, and stretched-exponential relaxation times T1s (or T1s) is the decisive parameter for the estimation of k or Swi of porous sandstones by other than direct

  8. Quantum Pattern Recognition With Liquid State NMR

    E-print Network

    Neigovzen, Rodion; Sollacher, Rudolf; Glaser, Steffen J

    2008-01-01

    A novel quantum pattern recognition scheme is presented, which combines the idea of a classic Hopfield neural network with quantum adiabatic computation. Both the input and the memorized patterns are represented by means of the problem Hamiltonian. In contrast to classic neural networks, the algorithm can simultaneously return multiple recognized patterns. The approach also promises extension of classic memory capacity. A proof of principle for the algorithm for two qubits is provided using a liquid state NMR quantum computer.

  9. NMR Characterizations of Properties of Heterogeneous Media

    SciTech Connect

    Watson, A. Ted; Phan, Jack; Uh, Jinsoo; Michalak, Rudi; Xue, Song

    2003-01-28

    The overall goal of this project was to develop reliable methods for resolving macroscopic properties important for describing the flow of one or more fluid phases in reservoirs from formation measurements. Completed the facilities to house our new NMR imager, the equipment has been delivered and installed. New experimental designs will provide for more reliable estimation of permeability distributions were evaluated. Designed and built a new core holder to incorporate one of the new experimental designs.

  10. digestive mixture by 2H NMR

    Microsoft Academic Search

    Philip W. Westerman

    H nuclear magnetic resonance (NMR) spectra were obtained at 30.87 MHz for 8% (w\\/v) aqueous disper- sions of mixtures of bile salts (MBS), mixed intestinal lipids (MIL; myristic acid, monomyristoylglycerol, dimyristoylphos- phatidylcholine = 5:1:1), and cholesterol, in which a single lipid component is selectively 2H-labeled. Using the observa- tion that the time-averaged quadrupole splitting of a C2H3 group varies according

  11. NMR properties of petroleum reservoir fluids.

    PubMed

    Hirasaki, George J; Lo, Sho-Wei; Zhang, Ying

    2003-01-01

    NMR well logging of petroleum reservoir require the measurement of the NMR response of water, oil, and gas in the pore space of rocks at elevated temperatures and pressures. The viscosity of the oil may range from less than 1 cp to greater than 10,000 cp. Also, the oil and gas are not a single component but rather a broad distribution of components. The log mean T1 and T2 relaxation time of dead (gas free) crude oils are correlated with viscosity/temperature and Larmor frequency. The relaxation time of live oils deviate from the correlation for dead crude oils. This deviation can be correlated with the methane content of the oil. Natural gas in the reservoir has components other than methane. Mixing rules are developed to accommodate components such as ethane, propane, carbon dioxide, and nitrogen. Interpretation of NMR logs uses both relaxation and diffusion to distinguish the different fluids present in the formation. Crude oils have a broad spectrum of components but the relaxation time distribution and diffusion coefficient distribution are correlated. This correlation is used to distinguish crude oil from the response of water in the pores of the rock. This correlation can also be used to estimate viscosity of the crude oil. PMID:12850718

  12. RHODOPSIN-LIPID INTERACTIONS STUDIED BY NMR

    PubMed Central

    Soubias, Olivier; Gawrisch, Klaus

    2012-01-01

    The biophysical properties of the lipid matrix are known to influence function of integral membrane proteins. We report on a sample preparation method for reconstitution of membrane proteins which uses porous anodic aluminum oxide (AAO) filters with 200 nm-wide pores of high density. The substrate permits formation of tubular, single membranes that line the inner surface of pores. One square centimeter of filter with a thickness of 60 ?m yields on the order of 500 cm2 of solid-supported single bilayer surface, sufficient for NMR studies. The tubular bilayers are free of detergent, fully hydrated and accessible for ligands from one side of the membrane. The use of AAO filters greatly improves reproducibility of the reconstitution process such that the influence of protein on lipid order parameters can be studied with high resolution. As an example, results for the G protein-coupled receptor of class A, bovine rhodopsin, are shown. By 2H NMR order parameter measurements it is detected that rhodopsin insertion elastically deforms membranes near the protein. Furthermore, by 1H saturation-transfer NMR under conditions of magic-angle spinning (MAS), we demonstrate detection of preferences in interactions of rhodopsin with particular lipid species. It is assumed that function of integral membrane proteins depends on both protein-induced elastic deformations of the lipid matrix and preferences for interaction of the protein with particular lipid species in the first layer of lipids surrounding the protein. PMID:23374188

  13. NMR Studies of Cartilage Dynamics, Diffusion, Degradation

    NASA Astrophysics Data System (ADS)

    Huster, Daniel; Schiller, Jürgen; Naji, Lama; et al.

    An increasing number of people is suffering from rheumatic diseases, and, therefore, methods of early diagnosis of joint degeneration are urgently required. For their establishment, however, an improved knowledge about the molecular organisation of cartilage would be helpful. Cartilage consists of three main components: Water, collagen and chondroitin sulfate (CS) that is (together with further polysaccharides and proteins) a major constituent of the proteoglycans of cartilage. 1H and 13C MAS (magic-angle spinning) NMR (nuclear magnetic resonance) opened new perspectives for the study of the macromolecular components in cartilage. We have primarily studied the mobilities of CS and collagen in bovine nasal and pig articular cartilage (that differ significantly in their collagen/polysaccharide content) by measuring 13C NMR relaxation times as well as the corresponding 13C CP (cross polarisation) MAS NMR spectra. These data clearly indicate that the mobility of cartilage macromolecules is broadly distributed from almost completely rigid (collagen) to highly mobile (polysaccharides), which lends cartilage its mechanical strength and shock-absorbing properties.

  14. Rhodopsin-lipid interactions studied by NMR.

    PubMed

    Soubias, Olivier; Gawrisch, Klaus

    2013-01-01

    The biophysical properties of the lipid matrix are known to influence function of integral membrane proteins. We report on a sample preparation method for reconstitution of membrane proteins which uses porous anodic aluminum oxide (AAO) filters with 200-nm-wide pores of high density. The substrate permits formation of tubular, single membranes that line the inner surface of pores. One square centimeter of filter with a thickness of 60?m yields on the order of 500cm(2) of solid-supported single bilayer surface, sufficient for NMR studies. The tubular bilayers are free of detergent, fully hydrated, and accessible for ligands from one side of the membrane. The use of AAO filters greatly improves reproducibility of the reconstitution process such that the influence of protein on lipid order parameters can be studied with high resolution. As an example, results for the G protein-coupled receptor of class A, bovine rhodopsin, are shown. By (2)H NMR order parameter measurements, it is detected that rhodopsin insertion elastically deforms membranes near the protein. Furthermore, by (1)H saturation-transfer NMR under conditions of magic angle spinning, we demonstrate detection of preferences in interactions of rhodopsin with particular lipid species. It is assumed that function of integral membrane proteins depends on both protein-induced elastic deformations of the lipid matrix and preferences for interaction of the protein with particular lipid species in the first layer of lipids surrounding the protein. PMID:23374188

  15. Pure-exchange solid-state NMR.

    PubMed

    deAzevedo, E R; Bonagamba, T J; Schmidt-Rohr, K

    2000-01-01

    Three exchange nuclear magnetic resonance (NMR) techniques are presented that yield (13)C NMR spectra exclusively of slowly reorienting segments, suppressing the often dominant signals of immobile components. The first technique eliminates the diagonal ridge that usually dominates two-dimensional (2D) exchange NMR spectra and that makes it hard to detect the broad and low off-diagonal exchange patterns. A modulation of the 2D exchange spectrum by the sine-square of a factor which is proportional to the difference between evolution and detection frequencies is generated by fixed additional evolution and detection periods of duration tau, yielding a 2D pure-exchange (PUREX) spectrum. Smooth off-diagonal intensity is obtained by systematically incrementing tau and summing up the resulting spectra. The related second technique yields a static one-dimensional (1D) spectrum selectively of the exchanging site(s), which can thus be identified. Efficient detection of previously almost unobservable slow motions in a semicrystalline polymer is demonstrated. The third approach, a 1D pure-exchange experiment under magic-angle spinning, is an extension of the exchange-induced sideband (EIS) method. A TOSS (total suppression of sidebands) spectrum obtained after the same number of pulses and delays, with a simple swap of z periods, is subtracted from the EIS spectrum, leaving only the exchange-induced sidebands and a strong, easily detected centerband of the mobile site(s). PMID:10617438

  16. NMR quantitation: influence of RF inhomogeneity.

    PubMed

    Mo, Huaping; Harwood, John; Raftery, Daniel

    2011-10-01

    The NMR peak integral is ideally linearly dependent on the sine of excitation angle (?), which has provided unsurpassed flexibility in quantitative NMR by allowing the use of a signal of any concentration as the internal concentration reference. Controlling the excitation angle is particularly critical for solvent proton concentration referencing to minimize the negative impact of radiation damping, and to reduce the risk of receiver gain compression. In practice, due to the influence of RF inhomogeneity for any given probe, the observed peak integral is not exactly proportional to sin ?. To evaluate the impact quantitatively, we introduce a RF inhomogeneity factor I(?) as a function of the nominal pulse excitation angle and propose a simple calibration procedure. Alternatively, I(?) can be calculated from the probe's RF profile, which can be readily obtained as a gradient image of an aqueous sample. Our results show that without consideration of I(?), even for a probe with good RF homogeneity, up to 5% error can be introduced due to different excitation pulse angles used for the analyte and the reference. Hence, a simple calibration of I(?) can eliminate such errors and allow an accurate description of the observed NMR signal's dependence on the excitation angle in quantitative analysis. PMID:21919056

  17. Universal quantitative NMR analysis of complex natural samples.

    PubMed

    Simmler, Charlotte; Napolitano, José G; McAlpine, James B; Chen, Shao-Nong; Pauli, Guido F

    2014-02-01

    Nuclear Magnetic Resonance (NMR) is a universal and quantitative analytical technique. Being a unique structural tool, NMR also competes with metrological techniques for purity determination and reference material analysis. In pharmaceutical research, applications of quantitative NMR (qNMR) cover mostly the identification and quantification of drug and biological metabolites. Offering an unbiased view of the sample composition, and the possibility to simultaneously quantify multiple compounds, qNMR has become the method of choice for metabolomic studies and quality control of complex natural samples such as foods, plants or herbal remedies, and biofluids. In this regard, NMR-based metabolomic studies, dedicated to both the characterization of herbal remedies and clinical diagnosis, have increased considerably. PMID:24484881

  18. Multidimensional spatial-spectral holographic interpretation of NMR photography

    NASA Astrophysics Data System (ADS)

    Kiruluta, Andrew J. M.

    2006-05-01

    A spectral holographic interpretation arises naturally in nuclear magnetic resonance (NMR) photography from either the intrinsic chemical shift anisotropy of the spin system or the field inhomogeneity due to the applied spatial encoding gradients. We can thus think of NMR photography as arising from a "diffraction" off a spatial-spectral holographic grating. The spatial holographic component arises from a high dielectric constant (>50) of the NMR medium at high field strength (>4T) when the excitation wavelength is commensurate with the size of the NMR sample; otherwise, it is a volume spectral holographic grating. In this paper, the NMR localized spectroscopy (imaging) equation is derived from the principles of spatial-spectral holography. Holographic properties of storage and programmable time delay and time reversal are shown to follow naturally from this viewpoint and are experimentally demonstrated in an inhomogeneously broadened NMR sample. These ideas are shown to be extendable to complex signal processing functions such as recognition, correlations, and triple products.

  19. Universal Quantitative NMR Analysis of Complex Natural Samples

    PubMed Central

    Simmler, Charlotte; Napolitano, José G.; McAlpine, James B.; Chen, Shao-Nong; Pauli, Guido F.

    2013-01-01

    Nuclear Magnetic Resonance (NMR) is a universal and quantitative analytical technique. Being a unique structural tool, NMR also competes with metrological techniques for purity determination and reference material analysis. In pharmaceutical research, applications of quantitative NMR (qNMR) cover mostly the identification and quantification of drug and biological metabolites. Offering an unbiased view of the sample composition, and the possibility to simultaneously quantify multiple compounds, qNMR has become the method of choice for metabolomic studies and quality control of complex natural samples such as foods, plants or herbal remedies, and biofluids. In this regard, NMR-based metabolomic studies, dedicated to both the characterization of herbal remedies and clinical diagnosis, have increased considerably. PMID:24484881

  20. Fast automated protein NMR data collection and assignment by ADAPT-NMR on Bruker spectrometers.

    PubMed

    Lee, Woonghee; Hu, Kaifeng; Tonelli, Marco; Bahrami, Arash; Neuhardt, Elizabeth; Glass, Karen C; Markley, John L

    2013-11-01

    ADAPT-NMR (Assignment-directed Data collection Algorithm utilizing a Probabilistic Toolkit in NMR) supports automated NMR data collection and backbone and side chain assignment for [U-(13)C, U-(15)N]-labeled proteins. Given the sequence of the protein and data for the orthogonal 2D (1)H-(15)N and (1)H-(13)C planes, the algorithm automatically directs the collection of tilted plane data from a variety of triple-resonance experiments so as to follow an efficient pathway toward the probabilistic assignment of (1)H, (13)C, and (15)N signals to specific atoms in the covalent structure of the protein. Data collection and assignment calculations continue until the addition of new data no longer improves the assignment score. ADAPT-NMR was first implemented on Varian (Agilent) spectrometers [A. Bahrami, M. Tonelli, S.C. Sahu, K.K. Singarapu, H.R. Eghbalnia, J.L. Markley, PLoS One 7 (2012) e33173]. Because of broader interest in the approach, we present here a version of ADAPT-NMR for Bruker spectrometers. We have developed two AU console programs (ADAPT_ORTHO_run and ADAPT_NMR_run) that run under TOPSPIN Versions 3.0 and higher. To illustrate the performance of the algorithm on a Bruker spectrometer, we tested one protein, chlorella ubiquitin (76 amino acid residues), that had been used with the Varian version: the Bruker and Varian versions achieved the same level of assignment completeness (98% in 20 h). As a more rigorous evaluation of the Bruker version, we tested a larger protein, BRPF1 bromodomain (114 amino acid residues), which yielded an automated assignment completeness of 86% in 55 h. Both experiments were carried out on a 500 MHz Bruker AVANCE III spectrometer equipped with a z-gradient 5 mm TCI probe. ADAPT-NMR is available at http://pine.nmrfam.wisc.edu/ADAPT-NMR in the form of pulse programs, the two AU programs, and instructions for installation and use. PMID:24091140

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

    SciTech Connect

    Hirasaki, George J.; Mohanty, Kishore K.

    2003-02-10

    The objective of this project was to characterize the fluid properties and fluid-rock interactions that are needed for formation evaluation by NMR well logging. The advances made in the understanding of NMR fluid properties are summarized in a chapter written for an AAPG book on NMR well logging. This includes live oils, viscous oils, natural gas mixtures, and the relation between relaxation time and diffusivity.

  2. Understanding NMR relaxometry of partially water-saturated rocks

    NASA Astrophysics Data System (ADS)

    Mohnke, O.; Jorand, R.; Nordlund, C.; Klitzsch, N.

    2015-06-01

    Nuclear magnetic resonance (NMR) relaxometry measurements are commonly used to characterize the storage and transport properties of water-saturated rocks. Estimations of these properties are based on the direct link of the initial NMR signal amplitude to porosity (water content) and of the NMR relaxation time to pore size. Herein, pore shapes are usually assumed to be spherical or cylindrical. However, the NMR response at partial water saturation for natural sediments and rocks may differ strongly from the responses calculated for spherical or cylindrical pores, because these pore shapes do not account for water menisci remaining in the corners of desaturated angular pores. Therefore, we consider a bundle of pores with triangular cross sections. We introduce analytical solutions of the NMR equations at partial saturation of these pores, which account for water menisci of desaturated pores. After developing equations that describe the water distribution inside the pores, we calculate the NMR response at partial saturation for imbibition and drainage based on the deduced water distributions. For this pore model, the NMR amplitudes and NMR relaxation times at partial water saturation strongly depend on pore shape, i.e., arising from the capillary pressure and pore shape-dependent water distribution in desaturated pores with triangular cross sections. Even so, the NMR relaxation time at full saturation only depends on the surface-to-volume ratio of the pore. Moreover, we show the qualitative agreement of the saturation-dependent relaxation-time distributions of our model with those observed for rocks and soils.

  3. Review of advances in coupling electrochemistry and liquid state NMR.

    PubMed

    Bussy, Ugo; Boujtita, Mohammed

    2015-05-01

    The coupling of electrochemistry and NMR spectroscopy (EC-NMR) may present an interesting approach in the environmental oxidative degradation or metabolism studies. This review presents experimental advances in the field of EC-NMR and highlights the main advantages and drawbacks of in situ and on line of NMR spectroelectrochemistry. The analysis of NMR spectra recorded in situ or on line EC-NMR permits to elucidate the reaction pathway of the electrochemical oxidation reactions and could constitute a fast way for monitoring unstable species as for instance quinone and quinone imine structures without using any coupling agents. The use of 1D and 2D NMR coupled with electrochemistry may leads to the elucidation of the major species produced from the electrochemical oxidation process. The present review gives an overview about the development of the electrochemical cells which can operate on line or in situ with NMR measurements. Future developments and potential applications of EC-NMR are also discussed. PMID:25702997

  4. Advanced fluid-typing methods for NMR logging

    Microsoft Academic Search

    Ranhong Xie; Lizhi Xiao

    2011-01-01

    In recent years, nuclear magnetic resonance (NMR) has been increasingly used for fluidtyping in well-logging because of the\\u000a improved generations of NMR logging tools. This paper first discusses the applicable conditions of two one-dimensional NMR\\u000a methods: the dual TW method and dual TE method. Then, the two-dimensional (T\\u000a 2, D) and (T\\u000a 2, T\\u000a 1) NMR methods are introduced. These

  5. Advances of unilateral mobile NMR in nondestructive materials testing.

    PubMed

    Blümich, Bernhard; Casanova, Federico; Perlo, Juan; Anferova, Sophia; Anferov, Vladimir; Kremer, Kai; Goga, Nicolae; Kupferschläger, Klaus; Adams, Michael

    2005-02-01

    Unilateral mobile NMR employs portable instrumentation with sensors, which are applied to the object from one side. Based on the principles of well-logging NMR, a hand-held sensor, the NMR-MOUSE (MObile Universal Surface Explorer) has been developed for nondestructive materials testing. In the following, a number of new applications of unilateral NMR in materials science are reviewed. They are the state assessment of polyethylene pipes, the characterization of wood, the in situ evaluation of stone conservation treatment, high-resolution profiling of rubber tubes and 2-D imaging for defect analysis in rubber products. PMID:15833612

  6. New generation NMR bioreactor coupled with high-resolution NMR spectroscopy leads to novel discoveries in Moorella thermoaceticum metabolic profiles

    SciTech Connect

    Xue, Junfeng; Isern, Nancy G.; Ewing, R James; Liyu, Andrey V.; Sears, Jesse A.; Knapp, Harlan; Iversen, Jens; Sisk, Daniel R.; Ahring, Birgitte K.; Majors, Paul D.

    2014-06-20

    An in-situ nuclear magnetic resonance (NMR) bioreactor was developed and employed to monitor microbial metabolism under batch-growth conditions in real time. We selected Moorella thermoacetica ATCC 49707 as a test case. M. thermoacetica (formerly Clostridium thermoaceticum) is a strictly anaerobic, thermophilic, acetogenic, gram-positive bacterium with potential for industrial production of chemicals. The metabolic profiles of M. thermoacetica were characterized during growth in batch mode on xylose (a component of lignocellulosic biomass) using the new generation NMR bioreactor in combination with high-resolution, high sensitivity NMR (HR-NMR) spectroscopy. In-situ NMR measurements were performed using water-suppressed H-1 NMR spectroscopy at an NMR frequency of 500 MHz, and aliquots of the bioreactor contents were taken for 600 MHz HR-NMR spectroscopy at specific intervals to confirm metabolite identifications and expand metabolite coverage. M. thermoacetica demonstrated the metabolic potential to produce formate, ethanol and methanol from xylose, in addition to its known capability of producing acetic acid. Real-time monitoring of bioreactor conditions showed a temporary pH decrease, with a concomitant increase in formic acid during exponential growth. Fermentation experiments performed outside of the magnet showed that the strong magnetic field employed for NMR detection did not significantly affect cell metabolism. Use of the in-situ NMR bioreactor facilitated monitoring of the fermentation process in real time, enabling identification of intermediate and end-point metabolites and their correlation with pH and biomass produced during culture growth. Real-time monitoring of culture metabolism using the NMR bioreactor in combination with the HR-NMR spectroscopy will allow optimization of the metabolism of microorganisms producing valuable bioproducts.

  7. Lithium Polymer Electrolytes and Solid State NMR

    NASA Technical Reports Server (NTRS)

    Berkeley, Emily R.

    2004-01-01

    Research is being done at the Glenn Research Center (GRC) developing new kinds of batteries that do not depend on a solution. Currently, batteries use liquid electrolytes containing lithium. Problems with the liquid electrolyte are (1) solvents used can leak out of the battery, so larger, more restrictive, packages have to be made, inhibiting the diversity of application and decreasing the power density; (2) the liquid is incompatible with the lithium metal anode, so alternative, less efficient, anodes are required. The Materials Department at GRC has been working to synthesize polymer electrolytes that can replace the liquid electrolytes. The advantages are that polymer electrolytes do not have the potential to leak so they can be used for a variety of tasks, small or large, including in the space rover or in space suits. The polymers generated by Dr. Mary Ann Meador's group are in the form of rod -coil structures. The rod aspect gives the polymer structural integrity, while the coil makes it flexible. Lithium ions are used in these polymers because of their high mobility. The coils have repeating units of oxygen which stabilize the positive lithium by donating electron density. This aids in the movement of the lithium within the polymer, which contributes to higher conductivity. In addition to conductivity testing, these polymers are characterized using DSC, TGA, FTIR, and solid state NMR. Solid state NMR is used in classifying materials that are not soluble in solvents, such as polymers. The NMR spins the sample at a magic angle (54.7') allowing the significant peaks to emerge. Although solid state NMR is a helpful technique in determining bonding, the process of preparing the sample and tuning it properly are intricate jobs that require patience; especially since each run takes about six hours. The NMR allows for the advancement of polymer synthesis by showing if the expected results were achieved. Using the NMR, in addition to looking at polymers, allows for participation on a variety of other projects, including aero-gels and carbon graphite mat en als. The goals of the polymer electrolyte research are to improve the physical properties of the polymers. This includes improving conductivity, durability, and expanding the temperature range over which it is effective. Currently, good conductivity is only present at high temperatures. My goals are to experiment with different arrangements of rods and coils to achieve these desirable properties. Some of my experiments include changing the number of repeat units in the polymer, the size of the diamines, and the types of coil. Analysis of these new polymers indicates improvement in some properties, such as lower glass transition temperature; however, they are not as flexible as desired. With further research we hope to produce polymers that encompass all of these properties to a high degree.

  8. The application of LC-NMR and LC-SPE-NMR to compositional studies of natural organic matter.

    PubMed

    Simpson, Andre J; Tseng, Li-Hong; Simpson, Myrna J; Spraul, Manfred; Braumann, Ulrich; Kingery, William L; Kelleher, Brian P; Hayes, Michael H B

    2004-12-01

    Non-living natural organic matter (NOM) is ubiquitous in the oceans, atmosphere, sediments, and soils, and represents the most abundant organic carbon reserves on earth. However, a large proportion is considered to be "molecularly uncharacterized" because the inherent complexity of NOM is problematic when applying conventional analytical techniques. This manuscript presents initial applications of LC-NMR (1H) and LC-SPE-NMR (1H) to the studies of NOM isolated from water and soil. LC-NMR is applied to dissolved natural organic matter (DNOM) collected from freshwater environments, and both LC-NMR and LC-SPE-NMR are applied to an alkaline soil extract. The polar and complex nature of the DNOM samples limits conventional reversed phase separation, which can be partially overcome with the use of an ion pair reagent, although such an approach further complicates the NMR detection. LC-SPE-NMR of the soil alkaline extract was encouraging, and specific components in the mixture could be assigned. This work demonstrates that it is both possible to separate and concentrate specific components in NOM such that NMR detection is possible. As NMR information will be critical in unraveling the novel and/or complex structures in NOM this represents a key analytical hurdle in this area. PMID:15565221

  9. The use of NMR spectroscopy to validate NMR logs from deeply buried reservoir sandstones

    Microsoft Academic Search

    H Rueslåtten; T Eidesmo; K. A Lehne; O. M Relling

    1998-01-01

    A Lower Jurassic deeply buried sandstone oil reservoir offshore Mid Norway was logged with NUMAR's MRIL-C tool. The NML data have been compared with standard logs as well as laboratory NMR and standard petrophysical core measurements. The two formations studied are in the oil zone, Formation A being characterised by an extensive distribution of pore lining chlorite, while asphalt staining

  10. NMR measurement of bitumen at different temperatures.

    PubMed

    Yang, Zheng; Hirasaki, George J

    2008-06-01

    Heavy oil (bitumen) is characterized by its high viscosity and density, which is a major obstacle to both well logging and recovery. Due to the lost information of T2 relaxation time shorter than echo spacing (TE) and interference of water signal, estimation of heavy oil properties from NMR T2 measurements is usually problematic. In this work, a new method has been developed to overcome the echo spacing restriction of NMR spectrometer during the application to heavy oil (bitumen). A FID measurement supplemented the start of CPMG. Constrained by its initial magnetization (M0) estimated from the FID and assuming log normal distribution for bitumen, the corrected T2 relaxation time of bitumen sample can be obtained from the interpretation of CPMG data. This new method successfully overcomes the TE restriction of the NMR spectrometer and is nearly independent on the TE applied in the measurement. This method was applied to the measurement at elevated temperatures (8-90 degrees C). Due to the significant signal-loss within the dead time of FID, the directly extrapolated M0 of bitumen at relatively lower temperatures (<60 degrees C) was found to be underestimated. However, resulting from the remarkably lowered viscosity, the extrapolated M0 of bitumen at over 60 degrees C can be reasonably assumed to be the real value. In this manner, based on the extrapolation at higher temperatures (> or = 60 degrees C), the M0 value of bitumen at lower temperatures (<60 degrees C) can be corrected by Curie's Law. Consequently, some important petrophysical properties of bitumen, such as hydrogen index (HI), fluid content and viscosity were evaluated by using corrected T2. PMID:18387325

  11. CHARACTERIZATION OF METABOLITES IN SMALL FISH BIOFLUIDS AND TISSUES BY NMR SPECTROSCOPY

    EPA Science Inventory

    Nuclear magnetic resonance (NMR) spectroscopy has been utilized for assessing ecotoxicity in small fish models by means of metabolomics. Two fundamental challenges of NMR-based metabolomics are the detection limit and characterization of metabolites (or NMR resonance assignments...

  12. NMR spectroscopic analysis of neferine and isoliensinine.

    PubMed

    Yang, Jian; Zhou, Kailan

    2004-11-01

    Neferine and isoliensinine are the two major compositions of the Chinese medicine lotus plumule. They have extensive cardiovascular activity, such as antiarrhythmic, antithrombic and antihypertensive. In order to confirm the structures reported in the literature by explicit 1H and 13C assignments, we used a series of NMR experiments including 1H, 1H-COSY, HSQC and HMBC. The absolute configuration of neferine (C-1 and C-1') was determined as R and S and that of isoliensinine (C-1 and C-1') was determined as R and R. PMID:15386549

  13. Algorithmic Cooling in Liquid State NMR

    E-print Network

    Yosi Atia; Yuval Elias; Tal Mor; Yossi Weinstein

    2014-11-17

    Algorithmic cooling is a method that employs thermalization to increase the qubits' purification level, namely it reduces the qubit-system's entropy. We utilized gradient ascent pulse engineering (GRAPE), an optimal control algorithm, to implement algorithmic cooling in liquid state nuclear magnetic resonance. Various cooling algorithms were applied onto the three qubits of 13C2-trichloroethylene, cooling the system beyond Shannon's entropy bound in several different ways. For example, in one experiment a carbon qubit was cooled by a factor of 4.61. This work is a step towards potentially integrating tools of NMR quantum computing into in vivo magnetic resonance spectroscopy.

  14. MULTIPLE-QUANTUM NMR IN SOLIDS

    SciTech Connect

    Yen, Y-S.

    1982-11-01

    Time domain multiple-quantum (MQ) nuclear magnetic resonance (NMR) spectroscopy is a powerful tool for spectral simplification and for providing new information on molecular dynamics. In this thesis, applications of MQ NMR are presented and show distinctly the advantages of this method over the conventional single-quantum NMR. Chapter 1 introduces the spin Hamiltonians, the density matrix formalism and some basic concepts of MQ NMR spectroscopy. In chapter 2, {sup 14}N double-quantum coherence is observed with high sensitivity in isotropic solution, using only the magnetization of bound protons. Spin echoes are used to obtain the homogeneous double-quantum spectrum and to suppress a large H{sub 2}O solvent signal. Chapter 3 resolves the main difficulty in observing high MQ transitions in solids. Due to the profusion of spin transitions in a solid, individual lines are unresolved. Excitation and detection of high quantum transitions by normal schemes are thus difficult. To ensure that overlapping lines add constructively and thereby to enhance sensitivity, time-reversal pulse sequences are used to generate all lines in phase. Up to 22-quantum {sup 1}H absorption in solid adamantane is observed. A time dependence study shows an increase in spin correlations as the excitation time increased. In chapter 4, a statistical theory of MQ second moments is developed for coupled spins of spin I = 1/2. The model reveals that the ratio of the average dipolar coupling to the rms value largely determines the dependence of second moments on the number of quanta. The results of this model are checked against computer-calculated and experimental second moments, and show good agreement. A simple scheme is proposed in chapter 5 for sensitivity improvement in a MQ experiment. The scheme involves acquiring all of the signal energy available in the detection period by applying pulsed spinlocking and sampling between pulses. Using this technique on polycrystalline adamantane, a large increase in sensitivity is observed. Correlation of motion of two interacting methyl groups is the subject of chapter 6. This system serves as a model for the study of hindered internal motion. Because the spin system is small and the motions are well-defined, the calculations involved are tractable. Group theory appropriate for nonrigid molecules is used to treat the change in the Hamiltonian as the methyl groups transit from correlated to uncorrelated motion. Results show that the four-quantum order alone is sufficient to distinguish between the two motions.

  15. NMR-based quantification of organic diphosphates

    PubMed Central

    Lenevich, Stepan

    2010-01-01

    Phosphorylated compounds are ubiquitous in life. Given their central role, many such substrates and analogues have been prepared for subsequent evaluation. Prior to biological experiments, it is typically necessary to determine the concentration of the target molecule in solution. Here we describe a method where concentrations of stock solutions of organic diphosphates and bisphosphonates are quantified using 31P NMR spectroscopy with standard instrumentation using a capillary tube with a secondary standard. The method is specific and is applicable down to a concentration of 200 ?M. The capillary tube provides the reference peak for quantification and deuterated solvent for locking. PMID:20833124

  16. NMR Characterizations of Properties of Heterogeneous Media

    SciTech Connect

    Uh, Jinsoo; Phan, Jack; Xue, Dong; Watson, A. Ted

    2003-01-28

    The overall goal of this project was to develop reliable methods for resolving macroscopic properties important for describing the flow of one or more fluid phases in reservoirs from formation measurements. During this reporting period, the determination of surface relaxivity from NMR data was investigated. A new method for determining the surface relaxivity from measured data was developed and tested with data obtained from an Exxon sample. The new method avoids the use of a certain mathematical short-time approximation in the data analysis, which has been shown to be unsuitable.

  17. NMR characterization of stabilized poly(methylmethacrylate)

    SciTech Connect

    Nelson, K.M.R.; Wallner, A.S. [MWSC, St. Joseph, MO (United States)

    1995-12-01

    Poly (methyl-methacrylate) (PMMA) is known to degrade when exposed to Ultra Violet radiation. Compounds such as Irganox and Poly (methyl-methacrylate-co-acrylonitrile) (PMMA-PAN) stabilize PMMA and lessen the degradation in the presence of UV light. Nuclear Magnetic Resonance (NMR) Spectroscopy was utilized to study these samples of stabilized PMMA. {sup 1}H, {sup 13}C, gated spin-echo (GASPE), and short range correlation two-dimensional spectra (HMQC) were collected allowing for characterization of the samples, evidence of chemical bonding of stabilizer to PMMA and quantification of the amount of stabilizer present.

  18. New generation NMR bioreactor coupled with high-resolution NMR spectroscopy leads to novel discoveries in Moorella thermoacetica metabolic profiles.

    PubMed

    Xue, Junfeng; Isern, Nancy G; Ewing, R James; Liyu, Andrei V; Sears, Jesse A; Knapp, Harlan; Iversen, Jens; Sisk, Daniel R; Ahring, Birgitte K; Majors, Paul D

    2014-10-01

    An in situ nuclear magnetic resonance (NMR) bioreactor was developed and employed to monitor microbial metabolism under batch growth conditions in real time. We selected Moorella thermoacetica ATCC 49707 as a test case. M. thermoacetica (formerly Clostridium thermoaceticum) is a strictly anaerobic, thermophilic, acetogenic, gram-positive bacterium with potential for industrial production of chemicals. The metabolic profiles of M. thermoacetica were characterized during growth in batch mode on xylose (a component of lignocellulosic biomass) using the new generation NMR bioreactor in combination with high-resolution NMR (HR-NMR) spectroscopy. In situ NMR measurements were performed using water-suppressed H-1 NMR spectroscopy at 500 MHz, and aliquots of the bioreactor contents were taken for 600-MHz HR-NMR spectroscopy at specific intervals to confirm metabolite identifications and expand metabolite coverage. M. thermoacetica demonstrated the metabolic potential to produce formate, ethanol, and methanol from xylose, in addition to its known capability of producing acetic acid. Real-time monitoring of bioreactor conditions showed a temporary pH decrease, with a concomitant increase in formic acid during exponential growth. Fermentation experiments performed outside of the magnet showed that the strong magnetic field employed for NMR detection did not significantly affect cell metabolism. Use of the in situ NMR bioreactor facilitated monitoring of the fermentation process, enabling identification of intermediate and endpoint metabolites and their correlation with pH and biomass produced during culture growth. Real-time monitoring of culture metabolism using the NMR bioreactor in combination with HR-NMR spectroscopy will allow optimization of the metabolism of microorganisms producing valuable bioproducts. PMID:24946863

  19. NMR of Redox Proteins of Plants, Yeasts and Photosynthetic Bacteria

    Microsoft Academic Search

    Xavier Trivelli; Sandrine Bouillac; Pascale Tsan; Isabelle Krimm; Jean-Marc Lancelin

    2004-01-01

    NMR spectroscopy has evolved dramatically over the past 15 years, establishing a new, reliable methodology for studying biomacromolecules at atomic resolution. The three-dimensional structure and dynamics of a biomolecule or a biomolecular complex is only one of the main types of information available using NMR. The spectral assignment to the specific nuclei of a biostructure is a very precise reflection

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

    SciTech Connect

    George J. Hirasaki; Kishore K. Mohanty

    2005-09-05

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

  1. Probe for high resolution NMR with sample reorientation

    DOEpatents

    Pines, Alexander (Berkeley, CA); Samoson, Ago (Tallinn, SU)

    1990-01-01

    An improved NMR probe and method are described which substantially improve the resolution of NMR measurements made on powdered or amorphous or otherwise orientationally disordered samples. The apparatus mechanically varies the orientation of the sample such that the time average of two or more sets of spherical harmonic functions are zero.

  2. A Fault-Tolerant Interconnect Mechanism for NMR Nanoarchitectures

    Microsoft Academic Search

    Ali Namazi; Mehrdad Nourani; Mohammad Saquib

    2010-01-01

    Redundancy techniques, such as N -tuple modular redundancy (NMR), has been widely used to correct faulty behavior of components and achieve high reliability. Almost all redundancy-based strategies rely on a majority voting. The voter, therefore, becomes a critical unit for the correct operation of any NMR system. In this paper, we propose a voterless fault-tolerant strategy to implement a robust

  3. Simulation of the Burgers equation by NMR quantum information processing

    Microsoft Academic Search

    Zhiying Chen; Jeffrey Yepez; David G. Cory

    2004-01-01

    We report on the implementation of Burgers equation as a type-II quantum computation on an NMR quantum information processor. Since the flow field evolving under the Burgers equation develops sharp features over time, this is a better test of liquid state NMR implementations of type-II quantum computers than the previous examples using the diffusion equation. In particular, we show that

  4. Journal of Biomolecular NMR, 11: 135152, 1998. KLUWER/ESCOM

    E-print Network

    Ikura, Mitsuhiko

    Journal of Biomolecular NMR, 11: 135­152, 1998. KLUWER/ESCOM © 1998 Kluwer Academic Publishers an array of isotope-assisted multidimensional heteronuclear NMR techniques. In some experiments (Flaherty et al., 1993; Ames et al., 1995a). The Ca2+-bound form of recoverin prolongs the visual

  5. Structure calculation, refinement and validation using CcpNmr Analysis.

    PubMed

    Skinner, Simon P; Goult, Benjamin T; Fogh, Rasmus H; Boucher, Wayne; Stevens, Tim J; Laue, Ernest D; Vuister, Geerten W

    2015-01-01

    CcpNmr Analysis provides a streamlined pipeline for both NMR chemical shift assignment and structure determination of biological macromolecules. In addition, it encompasses tools to analyse the many additional experiments that make NMR such a pivotal technique for research into complex biological questions. This report describes how CcpNmr Analysis can seamlessly link together all of the tasks in the NMR structure-determination process. It details each of the stages from generating NMR restraints [distance, dihedral, hydrogen bonds and residual dipolar couplings (RDCs)], exporting these to and subsequently re-importing them from structure-calculation software (such as the programs CYANA or ARIA) and analysing and validating the results obtained from the structure calculation to, ultimately, the streamlined deposition of the completed assignments and the refined ensemble of structures into the PDBe repository. Until recently, such solution-structure determination by NMR has been quite a laborious task, requiring multiple stages and programs. However, with the new enhancements to CcpNmr Analysis described here, this process is now much more intuitive and efficient and less error-prone. PMID:25615869

  6. Functional groups identified by solid state 13C NMR spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Animal manure is generally high in organic matter intensity so it is well suitable for 13C nuclear magnetic resonance (NMR) analysis. Solid-state 13C NMR techniques used in characterizing organic matter and its components include, but are not limited to, cross-polarization /magic angle spinning (CP...

  7. Xenon NMR measurements of permeability and tortuosity in reservoir rocks

    E-print Network

    Walsworth, Ronald L.

    Xenon NMR measurements of permeability and tortuosity in reservoir rocks Ruopeng Wanga,b , Tina of permeability, effective porosity and tortuosity on a variety of rock samples using NMR/MRI of thermal and laser of laser-polarized xenon into the rock core. Tortuosity is determined from measurements of the time

  8. AB3 Proton NMR Using Tensor Algebra Frank Rioux

    E-print Network

    Rioux, Frank

    AB3 Proton NMR Using Tensor Algebra Frank Rioux Professor Emeritus of Chemistry CSB|SJU The purpose of this tutorial is to calculate the NMR spectrum of a four proton AB3 system in Hz) are for the AB3 proton system 1,1dichloroethane at 60 MHz. A 350.0 B 120.0 Jab 10.00 Hamiltonian

  9. The Continuous Wavelet Transform, an Analysis Tool for NMR Spectroscopy

    Microsoft Academic Search

    D. Barache; J. P. Antoine; J. M. Dereppe

    1997-01-01

    The discrete wavelet transform has been used in NMR spectroscopy by several authors. We show here that the continuous wavelet transform (CWT) is also an efficient tool in that context. After reviewing briefly the analysis of spectral lines with the CWT, we discuss two applications specific to NMR, namely the removal of a large unwanted line and the rephasing of

  10. Interface between Microbiology and Structural Biology as viewed by NMR

    E-print Network

    Paris-Sud XI, Université de

    1 Interface between Microbiology and Structural Biology as viewed by NMR Muriel DELEPIERRE, Anne2007 Author manuscript, published in "Research in Microbiology 152, 8 (2001) 697-705" #12;2 Abstract in microbiology. 1 Introduction NMR and X-ray crystallography are the two most powerful tools available

  11. Identification of natural epimeric flavanone glycosides by NMR spectroscopy

    Microsoft Academic Search

    Federica Maltese; Cornelis Erkelens; Frank van der Kooy; Young Hae Choi; Robert Verpoorte

    2009-01-01

    Recently advanced analytical technology has provided evidence of the existence of stereoisomers of many natural products. Particularly, flavanones which might have two different configurations at C-2 exist in many food additives, e.g., citrus fruits. In this study, the possible stereoisomers of flavanone glycosides were identified by NMR spectroscopy. Based on NMR spectra of common flavanone glycosides such as naringin, hesperidin,

  12. SuspensionNMR Spectroscopyof Phosphinesand Carbonylnickel ComplexesImmobilizedon Silica

    E-print Network

    Bluemel, Janet

    SuspensionNMR Spectroscopyof Phosphinesand Carbonylnickel ComplexesImmobilizedon Silica K. DComplexes,Modifled Silica,"P CPA,{ASNMR Spectra The 31PsuspensionNMR spectraof silica)3Si(OEt)3(2), PPh2(C6H4)SiMerOEt(3), PPh2(C6H4)Si(OE03(4). Silica servesas a popular support, since

  13. 900-MHz NMR: Accelerating Scientific Discovery Scientific Innovation Through Integration

    E-print Network

    spectrometer, which recently saw its five-year anniversary of operation at EMSL, catalyzed the development operational for users in 2004. In the meantime, the manufacturer provided EMSL with two 600-MHz NMR spectrometers, followed by a significant discount on an 800-MHz NMR spectrometer, helping EMSL keep its state

  14. {sup 17}O NMR investigations of oxidative degradation in polymers

    SciTech Connect

    Alam, T.M.; Celina, M.; Assink, R.A.; Gillen, K.T.; Clough, R.L.

    1996-12-31

    We have initiated studies using both solution and solid state magic angle spinning {sup 17}O NMR for a series of oxidatively aged polymers. This short note reports the solution {sup 17}O NMR for oxidatively degraded polypropylene, ethylene-propylene-diene, polyisoprene, and nitrile rubber. Enriched O{sub 2} is used during the accelerated aging. 3 figs, 7 refs.

  15. Fixed point theory of iterative excitation schemes in NMR

    Microsoft Academic Search

    R. Tycko; A. Pines; J. Guckenheimer

    1985-01-01

    Iterative schemes for NMR have been developed by several groups. A theoretical framework based on mathematical dynamics is described for such iterative schemes in nonlinear NMR excitation. This is applicable to any system subjected to coherent radiation or other experimentally controllable external forces. The effect of the excitation, usually a pulse sequence, can be summarized by a propagator or superpropagator

  16. Probing Porous Media with NMR Measurements of Restricted Gas Diffusion

    Microsoft Academic Search

    R. W. Mair; G. P. Wong; D. Hoffmann; R. L. Walsworth; M. D. Hurlimann; L. M. Schwartz; S. Patz

    1999-01-01

    We probe the structure of porous media using NMR measurements of the time-dependent diffusion of xenon gas imbibed into the pore space. The primary advantages of gas-phase NMR, relative to previous measurements using water, are: (i) gas diffusion coefficients are orders of magnitude larger than those of liquids; and (ii) noble gases interact much less strongly with surfaces than do

  17. Detection of free chloride in concrete by NMR

    Microsoft Academic Search

    Haebum Yun; Mark E. Patton; James H. Garrett; Gary K. Fedder; Kevin M. Frederick; Jung-Jiin Hsu; Irving J. Lowe; Irving J. Oppenheim; Paul J. Sides

    2004-01-01

    Laboratory experiments to detect chloride in a cement matrix using pulse nuclear magnetic resonance (NMR) were conducted. The coils were in the centimeter scale and the magnetic field was 2.35 T. NMR signals were obtained from both aqueous chloride solution and samples of both regular and white Portland cement (WPC). A concrete sample from a sidewalk that had been in

  18. Permeability of Porous Media from Simulated NMR Response

    Microsoft Academic Search

    Irwan Hidajat; Mohit Singh; Josh Cooper; Kishore K. Mohanty

    2002-01-01

    Nuclear Magnetic Resonance (NMR) is an increasingly popular well-logging tool in petroleum industry because it is the only tool that attempts to estimate formation permeability. In this paper, spatially correlated porous media are generated. Permeabilities of these media are computed by the lattice Boltzmann method. NMR relaxation responses are simulated by a random walk technique and formation factors are computed

  19. Irreducible fluid saturation determined by pulsed field gradient NMR

    Microsoft Academic Search

    M. Appel; F. Stallmach; H. Thomann

    1998-01-01

    A new laboratory procedure, using a pulsed field gradient (PFG) NMR technique, for measuring the relative volumes of movable and nonmovable fluid in cores is reported. The saturations determined are in qualitative agreement with values obtained from mercury porosimetry and centrifuged gravimetric saturation measurements. An advantage of the PFG NMR method is that it is fast and does not require

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

    Microsoft Academic Search

    George J. Hirasaki; Kishore K. Mohanty

    2003-01-01

    The objective of this project was to characterize the fluid properties and fluid-rock interactions which are needed for formation evaluation by NMR well logging. NMR well logging is finding wide use in formation evaluation. The formation parameters commonly estimated were porosity, permeability, and capillary bound water. Special cases include estimation of oil viscosity, residual oil saturation, location of oil\\/water contact,

  1. Journal of Biomolecular NMR, 15: 114, 1999. KLUWER/ESCOM

    E-print Network

    Hong, Mei

    of Massachusetts, Amherst, MA 01003, U.S.A. Received 4 May 1999; Accepted 23 June 1999 Key words: isotopic labeling The comprehensive structure determination of isotopically labeled proteins by solid-state NMR requires sequence in such a methodology is isotopic labeling, used to enhance the signal-to-noise ratios of the NMR spec- tra. Although

  2. Current Topics Solution NMR of Large Molecules and Assemblies

    E-print Network

    Foster, Mark P.

    with the widespread use of uniform isotopic labeling of proteins and RNA with the NMR-active isotopes, 15N and 13C macromolecules (isotope labeling methods have expanded of uniform isotopic labeling of proteins and RNA with the NMR-active isotopes, 15 N and 13 C, opened the door

  3. NMR structure validation in relation to dynamics and structure determination.

    PubMed

    Vranken, Wim F

    2014-10-01

    NMR spectroscopy is a key technique for understanding the behaviour of proteins, especially highly dynamic proteins that adopt multiple conformations in solution. Overall, protein structures determined from NMR spectroscopy data constitute just over 10% of the Protein Data Bank archive. This review covers the validation of these NMR protein structures, but rather than describing currently available methodology, it focuses on concepts that are important for understanding where and how validation is most relevant. First, the inherent characteristics of the protein under study have an influence on quality and quantity of the distinct types of data that can be acquired from NMR experiments. Second, these NMR data are necessarily transformed into a model for use in a structure calculation protocol, and the protein structures that result from this reflect the types of NMR data used as well as the protein characteristics. The validation of NMR protein structures should therefore take account, wherever possible, of the inherent behavioural characteristics of the protein, the types of available NMR data, and the calculation protocol. These concepts are discussed in the context of 'knowledge based' and 'model versus data' validation, with suggestions for questions to ask and different validation categories to consider. The principal aim of this review is to stimulate discussion and to help the reader understand the relationships between the above elements in order to make informed decisions on which validation approaches are the most relevant in particular cases. PMID:25444697

  4. ORIGINAL PAPER NMR spectroscopy as a screening tool to validate

    E-print Network

    Paris-Sud XI, Université de

    for the rapid routine analysis of milk and milk substitutes. (NMR) (400 MHz 1 H)"" (SIMCA)(, ), (PLS) Dairy intolerance . Milk . Milk substitutes . Soy milk . Dairy products . . . . . . 1 Introduction DueORIGINAL PAPER NMR spectroscopy as a screening tool to validate nutrition labeling of milk, lactose

  5. Algorithmic cooling and scalable NMR quantum computers

    PubMed Central

    Boykin, P. Oscar; Mor, Tal; Roychowdhury, Vwani; Vatan, Farrokh; Vrijen, Rutger

    2002-01-01

    We present here algorithmic cooling (via polarization heat bath)—a powerful method for obtaining a large number of highly polarized spins in liquid nuclear-spin systems at finite temperature. Given that spin-half states represent (quantum) bits, algorithmic cooling cleans dirty bits beyond the Shannon's bound on data compression, by using a set of rapidly thermal-relaxing bits. Such auxiliary bits could be implemented by using spins that rapidly get into thermal equilibrium with the environment, e.g., electron spins. Interestingly, the interaction with the environment, usually a most undesired interaction, is used here to our benefit, allowing a cooling mechanism. Cooling spins to a very low temperature without cooling the environment could lead to a breakthrough in NMR experiments, and our “spin-refrigerating” method suggests that this is possible. The scaling of NMR ensemble computers is currently one of the main obstacles to building larger-scale quantum computing devices, and our spin-refrigerating method suggests that this problem can be resolved. PMID:11904402

  6. NMR investigation of iron-based superconductors

    NASA Astrophysics Data System (ADS)

    Imai, Takashi

    2010-03-01

    We report NMR investigation of the electronic properties of iron-based superconductors with primary focus on the 11 (FeSe) and 122 (Co-doped BaFe2As2) systems. From the ^77Se and ^75As NMR Knight shift K measurements, we will deduce the intrinsic temperature and concentration dependences of the uniform spin susceptibility, ?spin, in these systems. We will also demonstrate the evolution of antiferromagnetic spin fluctuations (AFSF) as a function of pressure (in FeSe) or the doping level (in Ba[Fe1-xCox]2As2). Our results show that the optimal superconducting phase exists in close proximity with SDW order; superconductivity sets in only after AFSF grow toward Tc. This work was carried out in collaboration with F.L. Ning and K. Ahilan (McMaster), T. McQueen and R.J. Cava (Princeton), A.S. Sefat, M.A. McGuire, B. C. Sales, and D. Mandrus (Oak Ridge), P. Cheng, B. Shen, and H.-H Wen (Chinese Academy of Sciences). The work at McMaster was supported by NSERC, CIFAR, and CFI.

  7. NMR assessment on bone simulated under microgravity

    NASA Astrophysics Data System (ADS)

    Ni, Q.; Qin, Y.

    Introduction Microgravity-induced bone loss has been suggested to be similar to disuse-osteoporosis on Earth which constitutes a challenging public health problem No current non-destructive method can provide the microstructural changes in bone particularly on cortical bone Recently the authors have applied low field nuclear magnetic resonance NMR spin-spin relaxation technique and computational analysis method to determine the porosity pore size distribution and microdamage of cortical bone 1-3 The studies by the authors have shown that this technology can be used to characterize microstructural changes as well as bone water distribution bound and mobile water changes of weightless treated simulating a microgravity condition turkey and mouse cortical bone We further determinate that the NMR spin-spin relaxation time T 2 spectrum derived parameters can be used as descriptions of bone quality e g matrix water distribution and porosity size distributions and alone or in combination with current techniques bone mineral density measurements more accurately predict bone mechanical properties Methods underline Bone sample preparation Two kinds of animal samples were collected and prepared for designed experiments from SUNY Cortical bones of the mid-diaphyses of the ulnae of 1-year-old male turkeys were dissected from freshly slaughtered animals Eight samples were categorized from normal or control and four samples were 4-week disuse treated by functionally isolated osteotomies disuse A total of 12

  8. The D0 solenoid NMR magnetometer

    SciTech Connect

    Sten Uldall Hansen Terry Kiper, Tom Regan, John Lofgren et al.

    2002-11-20

    A field monitoring system for the 2 Tesla Solenoid of the D0 detector is described. It is comprised of a very small NMR probe cabled to a DSP based signal processing board. The design magnetic field range is from 1.0 to 2.2 Tesla, corresponding to an RF frequency range of 42.57 to 93.67 MHz. The desired an accuracy is one part in 10{sup 5}. To minimize material in the interaction region of the D0 detector, the overall thickness of the NMR probe is 4 mm, including its mounting plate, and its width is 10 mm. To minimize cable mass, 4mm diameter IMR-100A cables are used for transmitting the RF signals from a nearby patch panel 25 meters to each of four probes mounted within the bore of the solenoid. RG213U cables 45 meters long are used to send the RF from the movable counting house to the patch panel. With this setup, the detector signal voltage at the moving counting room is in the range of 250-400 mV.

  9. High-resolution, high-pressure NMR studies of proteins.

    PubMed Central

    Jonas, J; Ballard, L; Nash, D

    1998-01-01

    Advanced high-resolution NMR spectroscopy, including two-dimensional NMR techniques, combined with high pressure capability, represents a powerful new tool in the study of proteins. This contribution is organized in the following way. First, the specialized instrumentation needed for high-pressure NMR experiments is discussed, with specific emphasis on the design features and performance characteristics of a high-sensitivity, high-resolution, variable-temperature NMR probe operating at 500 MHz and at pressures of up to 500 MPa. An overview of several recent studies using 1D and 2D high-resolution, high-pressure NMR spectroscopy to investigate the pressure-induced reversible unfolding and pressure-assisted cold denaturation of lysozyme, ribonuclease A, and ubiquitin is presented. Specifically, the relationship between the residual secondary structure of pressure-assisted, cold-denatured states and the structure of early folding intermediates is discussed. PMID:9649405

  10. Solid State OXYGEN17 NMR Studies of Hydrate in Biomolecules and Deuterium NMR Studies of Chain Dynamics in Crystalline bis

    Microsoft Academic Search

    Huiming Zhang

    1993-01-01

    There are two parts in this dissertation. In part one (chapter II-V), solid state ^{17 }O (I = 5\\/2) NMR is established as a useful and complementary approach to ^2H NMR for studying dynamic disorder of water of hydration in biomolecules. A highly efficient probe is designed and constructed from available small components for conducting these experiments. This reliable probe

  11. Improved nuclear magnetic resonance apparatus having semitoroidal rf coil for use in topical NMR and NMR imaging

    DOEpatents

    Fukushima, E.; Roeder, S.B.W.; Assink, R.A.; Gibson, A.A.V.

    1984-01-01

    An improved nuclear magnetic resonance (NMR) apparatus for use in topical magnetic resonance (TMR) spectroscopy and other remote sensing NMR applications includes a semitoroidal radio frequency (rf) coil. The semitoroidal rf coil produces an effective alternating magnetic field at a distance from the poles of the coil, so as to enable NMR measurements to be taken from selected regions inside an object, particularly including human and other living subjects. The semitoroidal rf coil is relatively insensitive to magnetic interference from metallic objects located behind the coil, thereby rendering the coil particularly suited for use in both conventional and superconducting NMR magnets. The semitoroidal NMR coil can be constructed so that it emits little or no excess rf electric field associated with the rf magnetic field, thus avoiding adverse effects due to dielectric heating of the sample or to any other interaction of the electric field with the sample.

  12. Combined chemometric analysis of (1)H NMR, (13)C NMR and stable isotope data to differentiate organic and conventional milk.

    PubMed

    Erich, Sarah; Schill, Sandra; Annweiler, Eva; Waiblinger, Hans-Ulrich; Kuballa, Thomas; Lachenmeier, Dirk W; Monakhova, Yulia B

    2015-12-01

    The increased sales of organically produced food create a strong need for analytical methods, which could authenticate organic and conventional products. Combined chemometric analysis of (1)H NMR-, (13)C NMR-spectroscopy data, stable-isotope data (IRMS) and ?-linolenic acid content (gas chromatography) was used to differentiate organic and conventional milk. In total 85 raw, pasteurized and ultra-heat treated (UHT) milk samples (52 organic and 33 conventional) were collected between August 2013 and May 2014. The carbon isotope ratios of milk protein and milk fat as well as the ?-linolenic acid content of these samples were determined. Additionally, the milk fat was analyzed by (1)H and (13)C NMR spectroscopy. The chemometric analysis of combined data (IRMS, GC, NMR) resulted in more precise authentication of German raw and retail milk with a considerably increased classification rate of 95% compared to 81% for NMR and 90% for IRMS using linear discriminate analysis. PMID:26041156

  13. Velocity imaging by ex situ NMR.

    PubMed

    Perlo, J; Casanova, F; Blümich, B

    2005-04-01

    A pulsed field gradient stimulated spin-echo NMR sequence is combined with imaging methods to spatially resolve velocity distributions and to measure 2D velocity maps ex situ. The implementation of these techniques in open sensors provides a powerful non-invasive tool to measure molecular displacement in a large number of applications inaccessible to conventional closed magnets. The method is implemented on an open tomograph that provides 3D spatial localization by combining slice selection in the presence of a uniform static magnetic field gradient along the depth direction with pulsed field gradients along the two lateral directions. Different pipe geometries are used to demonstrate that the sequence performs well even in the extremely inhomogeneous B0 and B1 fields of these sensors. PMID:15780917

  14. Estimating patient dielectric losses in NMR imagers.

    PubMed

    Redpath, T W; Hutchison, J M

    1984-01-01

    Dielectric losses in the patient may impair radiofrequency receiver coil sensitivity, and transmitter coil efficiency, in nuclear magnetic resonance (NMR) imagers. The frequency dependence of this loss mechanism is derived. Patient losses in a solenoidal head coil used for imaging heads were simulated by a cylindrical saline phantom. The frequency dependence of the loss introduced by the phantom can indicate whether dielectric losses in the patient will be significant compared to eddy current losses. The detuning caused by the phantom is used to calculate an upper limit for the distributed stray capacitance between coil and patient. Given the approximate conductivity of the patient, an upper limit for the dielectric loss can be estimated. Some methods of reducing patient dielectric losses are suggested. PMID:6530932

  15. NMR Experimental Demonstration of Probabilistic Quantum Cloning

    E-print Network

    Hongwei Chen; Dawei Lu; Bo Chong; Gan Qin; Xianyi Zhou; Xinhua Peng; Jiangfeng Du

    2011-04-19

    The method of quantum cloning is divided into two main categories: approximate and probabilistic quantum cloning. The former method is used to approximate an unknown quantum state deterministically, and the latter can be used to faithfully copy the state probabilistically. So far, many approximate cloning machines have been experimentally demonstrated, but probabilistic cloning remains an experimental challenge, as it requires more complicated networks and a higher level of precision control. In this work, we designed an efficient quantum network with a limited amount of resources, and performed the first experimental demonstration of probabilistic quantum cloning in an NMR quantum computer. In our experiment, the optimal cloning efficiency proposed by Duan and Guo [Phys. Rev. Lett. \\textbf{80}, 4999 (1998)] is achieved.

  16. Superconducting wire for NMR-tomography

    SciTech Connect

    Filkin, V.Y.; Plashkin, E.I.; Salunin, N.I.; Morozova, T.A.; Zelenskiy, G.K.; Vlasova, L.V.; Drobyshev, V.A.; Zinovev, V.G.; Yakovlev, B.V. (All-Union Scientific and Research Inst. of Inorganic Materials, 123060 Moscow (SU))

    1992-01-01

    The paper discusses the fabrication of Nb-Ti base superconducting wires having the superconductor packing factor of 15-20% and superconducting filaments 70-80 {mu}m dia. Three methods of precursor fabrication were tried. The NbTi-50 alloy base superconducting wire was fabricated to be used for the magnet system of a NMR-tomograph; the wire diameter is 0.85 mm; the packing factor is 16%; the maximum length of a single piece is 29 km{sub 2}. The critical current density is 6.1 {times} 10{sup 5} A/cm{sup 2} in the magnetic field of 1 T. The paper also presents the superconducting properties of similar wire on the NbTi-55 alloy base.

  17. NMR Metabolomics Analysis of Parkinson's Disease

    PubMed Central

    Lei, Shulei; Powers, Robert

    2015-01-01

    Parkinson's disease (PD) is a neurodegenerative disease, which is characterized by progressive death of dopaminergic neurons in the substantia nigra pars compacta. Although mitochondrial dysfunction and oxidative stress are linked to PD pathogenesis, its etiology and pathology remain to be elucidated. Metabolomics investigates metabolite changes in biofluids, cell lysates, tissues and tumors in order to correlate these metabolomic changes to a disease state. Thus, the application of metabolomics to investigate PD provides a systematic approach to understand the pathology of PD, to identify disease biomarkers, and to complement genomics, transcriptomics and proteomics studies. This review will examine current research into PD mechanisms with a focus on mitochondrial dysfunction and oxidative stress. Neurotoxin-based PD animal models and the rationale for metabolomics studies in PD will also be discussed. The review will also explore the potential of NMR metabolomics to address important issues related to PD treatment and diagnosis.

  18. Exploring RNA polymerase regulation by NMR spectroscopy.

    PubMed

    Drögemüller, Johanna; Strauß, Martin; Schweimer, Kristian; Wöhrl, Birgitta M; Knauer, Stefan H; Rösch, Paul

    2015-01-01

    RNA synthesis is a central process in all organisms, with RNA polymerase (RNAP) as the key enzyme. Multisubunit RNAPs are evolutionary related and are tightly regulated by a multitude of transcription factors. Although Escherichia coli RNAP has been studied extensively, only little information is available about its dynamics and transient interactions. This information, however, are crucial for the complete understanding of transcription regulation in atomic detail. To study RNAP by NMR spectroscopy we developed a highly efficient procedure for the assembly of active RNAP from separately expressed subunits that allows specific labeling of the individual constituents. We recorded [(1)H,(13)C] correlation spectra of isoleucine, leucine, and valine methyl groups of complete RNAP and the separately labeled ?' subunit within reconstituted RNAP. We further produced all RNAP subunits individually, established experiments to determine which RNAP subunit a certain regulator binds to, and identified the ? subunit to bind NusE. PMID:26043358

  19. ?-NMR study of boron in diamond

    NASA Astrophysics Data System (ADS)

    Izumikawa, T.; Mihara, M.; Matsuta, K.; Fukuda, M.; Ohtsubo, T.; Ohya, S.; Minamisono, T.

    2015-04-01

    A ?-NMR study of 12B implanted in diamond was performed in order to investigate the implantation sites and the defects. The maintained polarization of 12B was measured by use of widely modulated rf around the Larmor frequency ( ? = ? L ± 200 kHz) as a function of temperature from 160 K to 320 K. The observed polarization was found to be almost constant at about 0.9 % in this temperature range. The initial polarization for this system was obtained as about 8.1 %. Therefore about 10 % of the implanted 12B maintained its polarization in this frequency range. Conversely, about 90 % of the implanted 12B was undetected in the present experiment.

  20. Dynamic disorder and solid state NMR

    NASA Astrophysics Data System (ADS)

    Sergeev, N. A.; Olszewski, M.

    2008-04-01

    The temperature dependences of the second moment (M2) and spin-lattice relaxation times (T1 and T1?) in solids with dynamic disorder have been investigated assuming that the potential barrier E for the moving atom (or molecule) is a stochastic function of time. It has been shown that the temperature dependences of M2, T1 and T1? exhibit a significant dependence on the kind of standard deviation of the distribution of E and on the form of the activation energy Eb at frequency ?0 describing the temporal fluctuations of E. The obtained results have been applied to the interpretation of the temperature transformations of the second moment of 1H NMR spectra of the diffusing water molecules in the mineral natrolite.

  1. NMR data visualization, processing, and analysis on mobile devices.

    PubMed

    Cobas, Carlos; Iglesias, Isaac; Seoane, Felipe

    2015-08-01

    Touch-screen computers are emerging as a popular platform for many applications, including those in chemistry and analytical sciences. In this work, we present our implementation of a new NMR 'app' designed for hand-held and portable touch-controlled devices, such as smartphones and tablets. It features a flexible architecture formed by a powerful NMR processing and analysis kernel and an intuitive user interface that makes full use of the smart devices haptic capabilities. Routine 1D and 2D NMR spectra acquired in most NMR instruments can be processed in a fully unattended way. More advanced experiments such as non-uniform sampled NMR spectra are also supported through a very efficient parallelized Modified Iterative Soft Thresholding algorithm. Specific technical development features as well as the overall feasibility of using NMR software apps will also be discussed. All aspects considered the functionalities of the app allowing it to work as a stand-alone tool or as a 'companion' to more advanced desktop applications such as Mnova NMR. Copyright © 2015 John Wiley & Sons, Ltd. PMID:25924947

  2. Interactions between cations and peat organic matter monitored with NMR wideline, static and FFC NMR relaxometry

    NASA Astrophysics Data System (ADS)

    Schaumann, Gabriele E.; Conte, Pellegrino; Jäger, Alexander; Alonzo, Giuseppe; Bertmer, Marko

    2010-05-01

    The molecular size of humic substances is still under debate and is believed to range up to several hundred thousands Dalton, although a number of recent studies suggest much lower molecular weights. Nowadays an increasing number of authors suggest a model of molecular aggregates. One explanation why results on the molecular mass of humic materials are contradictory, may be that individual OM molecules are linked via intermolecular interactions, by bridges of water molecules or by cations bridging cation exchange sites (Schaumann, 2006a, b). Properties of such cross-linked systems can be similar to macromolecular systems revealing covalent cross-links. In this context, multivalent cations play an important ecological role, serving as reversible cross-linking agent. Formation and disruption of such cation bridges may close or open sorption sites in soil organic matter. Although cross-linking by multivalent cations has been proposed in many studies, the cross-linking effect has not yet been demonstrated on the molecular scale. The objective of this study was to investigate the interactions between cations and peat organic matter using NMR wideline techniques as well as static and fast field cycling (FFC) NMR relaxometry. Peat treated with solutions containing either Na+, Ca2+ or Al3+ was investigated in air-dried state for longitudinal relaxation times (T1) and NMR wideline characteristics. T1 distributions were separated into two Gaussian functions which were interpreted to represent two proton populations belonging to two environments of differing mobility. The relaxation rates (R1 = T1-1) in the cation treated samples spread over a range of 87-123 s-1 (R1a: fast component) and 32-42 s-1 (R1b: slow component). The rates in all treatments are significantly different from each other. and decrease in the order conditioned sample > desalinated sample > Na-treated sample. The treatment with multivalent cations affects R1a and R1b in different ways and needs more detailed explanation. Wideline proton NMR spectra can be used to quantify proton containing material, mainly water, based on their mobility. Spectra were decomposed into a Gaussian and Lorentzian line and changes to mobility after heat treatment indicate the water binding strength. In this study, differences in the various NMR parameters on the cation treatments will be presented and discussed with respect to the crosslinking hypothesis.

  3. Simultaneous Phase and Scatter Correction for NMR Datasets

    PubMed Central

    Worley, Bradley; Powers, Robert

    2014-01-01

    Nuclear magnetic resonance (NMR) spectroscopy has proven invaluable in the diverse field of chemometrics due to its ability to deliver information-rich spectral datasets of complex mixtures for analysis by techniques such as principal component analysis (PCA). However, NMR datasets present a unique challenge during preprocessing due to differences in phase offsets between individual spectra, thus complicating the correction of random dilution factors that may also occur. We show that simultaneously correcting phase and dilution errors in NMR datasets representative of metabolomics data yields improved cluster quality in PCA scores space, even with significant initial phase errors in the data. PMID:24489421

  4. Developments in high resolution NMR of inorganic solids

    SciTech Connect

    Pines, A. [Lawrence Berkeley National Lab., CA (United States)

    1996-12-31

    From the foundations laid by the pioneering work of J.S. Waugh at M.I.T., a number of advances in resolution and sensitivity have contributed to modem solid state nuclear magnetic resonance (NMR) and its applications to materials science. Among the recent developments at Berkeley aimed at high resolution spectroscopy in solids are multiple-quantum NMR, cross polarization of quadrupoles, multiple-axis spinning methods, zero field magnetic resonance and optically pumped xenon NMR of surfaces. Following the lecture we shall hear an update on the condition of Hartmann and Hahn.

  5. Characterization of a chiral nematic mesoporous organosilica using NMR

    NASA Astrophysics Data System (ADS)

    Manning, Alan; Shopsowitz, Kevin; Giese, Michael; MacLachlan, Mark; Dong, Ronald; Michal, Carl

    2012-10-01

    Using templation with nanocrystalline cellulose, a mesoporous organosilica film with a chiral nematic pore structure has recently been developed. [1] We have used a variety of Nuclear Magnetic Resonance (NMR) techniques to characterize the pore structure. The pore size distribution has been found by analyzing the freezing point depression of absorbed water via NMR cryoporometry. The effective longitudinal and transverse pore diameters for diffusing water were investigated with Pulsed-Field Gradient (PFG) NMR and compared to a 1-D connected-pore model. Preliminary data on testing imposed chiral ordering in absorbed liquid crystals is also presented. [4pt] [1] K.E. Shopsowitz et al. JACS 134(2), 867 (2012)

  6. Solid State NMR Studies of Amyloid Fibril Structure

    PubMed Central

    Tycko, Robert

    2011-01-01

    Current interest in amyloid fibrils stems from their involvement in neurodegenerative and other diseases and from their role as an alternative structural state for many peptides and proteins. Solid state NMR methods have the unique capability of providing detailed structural constraints for amyloid fibrils, sufficient for the development of full molecular models. In this article, recent progress in the application of solid state NMR to fibrils associated with Alzheimer’s disease, prion fibrils, and related systems is reviewed, along with relevant developments in solid state NMR techniques and technology. PMID:21219138

  7. NMR imaging of components and materials for DOE application

    SciTech Connect

    Richardson, B.R.

    1993-12-01

    The suitability for using NMR imaging to characterize liquid, polymeric, and solid materials was reviewed. The most attractive applications for NMR imaging appear to be liquid-filled porous samples, partially cured polymers, adhesives, and potting compounds, and composite polymers/high explosives containing components with widely varying thermal properties. Solid-state NMR line-narrowing and signal-enhancing markedly improve the imaging possibilities of true solid and materials. These techniques provide unique elemental and chemical shift information for highly complex materials and complement images with similar spatial resolution, such as X-ray computed tomography (CT).

  8. NMR contributions to structural dynamics studies of intrinsically disordered proteins.

    PubMed

    Konrat, Robert

    2014-04-01

    Intrinsically disordered proteins (IDPs) are characterized by substantial conformational plasticity. Given their inherent structural flexibility X-ray crystallography is not applicable to study these proteins. In contrast, NMR spectroscopy offers unique opportunities for structural and dynamic studies of IDPs. The past two decades have witnessed significant development of NMR spectroscopy that couples advances in spin physics and chemistry with a broad range of applications. This article will summarize key advances in basic physical-chemistry and NMR methodology, outline their limitations and envision future R&D directions. PMID:24656082

  9. Fragment-Based Drug Discovery Using NMR Spectroscopy

    PubMed Central

    Harner, Mary J.; Frank, Andreas O.; Fesik, Stephen W.

    2013-01-01

    Nuclear magnetic resonance (NMR) spectroscopy has evolved into a powerful tool for fragment-based drug discovery over the last two decades. While NMR has been traditionally used to elucidate the three-dimensional structures and dynamics of biomacromolecules and their interactions, it can also be a very valuable tool for the reliable identification of small molecules that bind to proteins and for hit-to-lead optimization. Here, we describe the use of NMR spectroscopy as a method for fragment-based drug discovery and how to most effectively utilize this approach for discovering novel therapeutics based on our experience. PMID:23686385

  10. 77Se-NMR einiger titanocendiselenolen-metallacyclen

    NASA Astrophysics Data System (ADS)

    Klapötke, Th.

    The first 77Se NMR was carried out on a titanocene diselenopyrocatechol derivative with Se bonded directly to the transition metal. Surprisingly, the Ti metallacycle shows, compared with Zr, a reversed shielding effect by proceeding from the non-cyclic Se system to the five-membered Se,Se' co-ordinated heterocycle. This reflects the different bonding system in Ti and Zr bis (cyclopentadienyl) dichalcogenolene complexes. The results are discussed on the basis of the 77Se NMR spectra, the dynamic 1H NMR spectra ( 1H DNMR), and the V. B. and M. O. bonding theories.

  11. Capillary toroid cavity detector for high pressure NMR

    DOEpatents

    Gerald, II, Rex E. (Brookfield, IL); Chen, Michael J. (Downers Grove, IL); Klingler, Robert J. (Glenview, IL); Rathke, Jerome W. (Honer Glen, IL); ter Horst, Marc (Chapel Hill, NC)

    2007-09-11

    A Toroid Cavity Detector (TCD) is provided for implementing nuclear magnetic resonance (NMR) studies of chemical reactions under conditions of high pressures and temperatures. A toroid cavity contains an elongated central conductor extending within the toroid cavity. The toroid cavity and central conductor generate an RF magnetic field for NMR analysis. A flow-through capillary sample container is located within the toroid cavity adjacent to the central conductor to subject a sample material flowing through the capillary to a static magnetic field and to enable NMR spectra to be recorded of the material in the capillary under a temperature and high pressure environment.

  12. Protein NMR Techniques, 3rd Methods in Molecular Biology, Springer Verlag (Humana Press), 2011

    E-print Network

    Linsley, Braddock K.

    Protein NMR Techniques, 3rd ed. Methods in Molecular Biology, Springer Verlag (Humana Press), 2011, 518 pages. The field of protein NMR spectroscopy has rapidly expanded into new areas of biochemistry of the latest innovations in the field of protein NMR. It focuses on the application of NMR to biochemistry

  13. NMR Methods, Applications and Trends for Groundwater Evaluation and Management

    NASA Astrophysics Data System (ADS)

    Walsh, D. O.; Grunewald, E. D.

    2011-12-01

    Nuclear magnetic resonance (NMR) measurements have a tremendous potential for improving groundwater characterization, as they provide direct detection and measurement of groundwater and unique information about pore-scale properties. NMR measurements, commonly used in chemistry and medicine, are utilized in geophysical investigations through non-invasive surface NMR (SNMR) or downhole NMR logging measurements. Our recent and ongoing research has focused on improving the performance and interpretation of NMR field measurements for groundwater characterization. Engineering advancements have addressed several key technical challenges associated with SNMR measurements. Susceptibility of SNMR measurements to environmental noise has been dramatically reduced through the development of multi-channel acquisition hardware and noise-cancellation software. Multi-channel instrumentation (up to 12 channels) has also enabled more efficient 2D and 3D imaging. Previous limitations in measuring NMR signals from water in silt, clay and magnetic geology have been addressed by shortening the instrument dead-time from 40 ms to 4 ms, and increasing the power output. Improved pulse sequences have been developed to more accurately estimate NMR relaxation times and their distributions, which are sensitive to pore size distributions. Cumulatively, these advancements have vastly expanded the range of environments in which SNMR measurements can be obtained, enabling detection of groundwater in smaller pores, in magnetic geology, in the unsaturated zone, and nearby to infrastructure (presented here in case studies). NMR logging can provide high-resolution estimates of bound and mobile water content and pore size distributions. While NMR logging has been utilized in oil and gas applications for decades, its use in groundwater investigations has been limited by the large size and high cost of oilfield NMR logging tools and services. Recently, engineering efforts funded by the US Department of Energy have produced an NMR logging tool that is much smaller and less costly than comparable oilfield NMR logging tools. This system is specifically designed for near surface groundwater investigations, incorporates small diameter probes (as small as 1.67 inches diameter) and man-portable surface stations, and provides NMR data and information content on par with oilfield NMR logging tools. A direct-push variant of this logging tool has also been developed. Key challenges associated with small diameter tools include inherently lower SNR and logging speeds, the desire to extend the sensitive zone as far as possible into unconsolidated formations, and simultaneously maintaining high power and signal fidelity. Our ongoing research in groundwater NMR aims to integrating surface and borehole measurements for regional-scale permeability mapping, and to develop in-place NMR sensors for long term monitoring of contaminant and remediation processes. In addition to groundwater resource characterization, promising new applications of NMR include assessing water content in ice and permafrost, management of groundwater in mining operations, and evaluation and management of groundwater in civil engineering applications.

  14. Structure elucidation and NMR spectral assignment of five new xanthones from the bark of Garcinia xanthochymus.

    PubMed

    Chen, Yu; Zhong, Fangfang; He, Hongwu; Hu, Yun; Zhu, Dan; Yang, Guangzhong

    2008-12-01

    Five new xanthones, namely Garcinexanthones A-E (1-5), were isolated from the barks of Garcinia xanthochymus. Their structures were elucidated by spectral analysis, primarily NMR, MS, and UV. The complete assignments of the (1)H NMR and (13)C NMR chemical shifts for the compounds were achieved by using 1D and 2D NMR techniques, including DEPT, HSQC, and HMBC NMR experiments. PMID:18800340

  15. Dynamic nuclear polarization for NMR : applications and hardware development

    E-print Network

    Casey, Andrew (Andrew Byron)

    2008-01-01

    solid State NMR (SSNMR) can determine molecular as well as supermolecular structure and dynamics. The low signal intensities make many of these experiments prohibitively long. Dynamic Nuclear Polarization provides a method ...

  16. Revisiting Protocols for the NMR Analysis of Bacterial Metabolomes

    PubMed Central

    Halouska, Steven; Zhang, Bo; Gaupp, Rosmarie; Lei, Shulei; Snell, Emily; Fenton, Robert J.; Barletta, Raul G.; Somerville, Greg A.; Powers, Robert

    2015-01-01

    Over the past decade, metabolomics has emerged as an important technique for systems biology. Measuring all the metabolites in a biological system provides an invaluable source of information to explore various cellular processes, and to investigate the impact of environmental factors and genetic modifications. Nuclear magnetic resonance (NMR) spectroscopy is an important method routinely employed in metabolomics. NMR provides comprehensive structural and quantitative information useful for metabolomics fingerprinting, chemometric analysis, metabolite identification and metabolic pathway construction. A successful metabolomics study relies on proper experimental protocols for the collection, handling, processing and analysis of metabolomics data. Critically, these protocols should eliminate or avoid biologically-irrelevant changes to the metabolome. We provide a comprehensive description of our NMR-based metabolomics procedures optimized for the analysis of bacterial metabolomes. The technical details described within this manuscript should provide a useful guide to reliably apply our NMR-based metabolomics methodology to systems biology studies.

  17. Exploring large coherent spin systems with solid state NMR

    E-print Network

    Cho, HyungJoon, Ph. D. Massachusetts Institute of Technology

    2005-01-01

    Solid state Nuclear Magnetic Resonance (NMR) allows us to explore a large coherent spin system and provides an ideal test-bed for studying strongly interacting multiple-spin system in a large Hilbert space. In this thesis, ...

  18. Investigation of Zeolite Nucleation and Growth Using NMR Spectroscopy 

    E-print Network

    Rivas Cardona, Alejandra

    2012-02-14

    and control of the zeolite properties. The primary objective of this dissertation is to determine the strength of organicinorganic interactions (i.e., the adsorption Gibbs energy) in transparent synthesis mixtures using PFG NMR spectroscopy, in order...

  19. Recent NMR developments applied to organic-inorganic materials.

    PubMed

    Bonhomme, Christian; Gervais, Christel; Laurencin, Danielle

    2014-02-01

    In this contribution, the latest developments in solid state NMR are presented in the field of organic-inorganic (O/I) materials (or hybrid materials). Such materials involve mineral and organic (including polymeric and biological) components, and can exhibit complex O/I interfaces. Hybrids are currently a major topic of research in nanoscience, and solid state NMR is obviously a pertinent spectroscopic tool of investigation. Its versatility allows the detailed description of the structure and texture of such complex materials. The article is divided in two main parts: in the first one, recent NMR methodological/instrumental developments are presented in connection with hybrid materials. In the second part, an exhaustive overview of the major classes of O/I materials and their NMR characterization is presented. PMID:24411829

  20. International NMR-based Environmental Metabolomics Intercomparison Exercise

    EPA Science Inventory

    Several fundamental requirements must be met so that NMR-based metabolomics and the related technique of metabonomics can be formally adopted into environmental monitoring and chemical risk assessment. Here we report an intercomparison exercise which has evaluated the effectivene...

  1. NMR methods for in-situ biofilm metabolism studies

    SciTech Connect

    Majors, Paul D.; Mclean, Jeffrey S.; Pinchuk, Gregory E.; Fredrickson, Jim K.; Gorby, Yuri A.; Minard, Kevin R.; Wind, Robert A.

    2005-09-01

    Novel procedures and instrumentation are described for nuclear magnetic resonance (NMR) spectroscopy and imaging studies of live, in situ microbial films. A perfused NMR/optical microscope sample chamber containing a planar biofilm support was integrated into a recirculation/dilution flow loop growth reactor system and used to grow in situ Shewanella oneidensis strain MR-1 biofilms. Localized NMR techniques were developed and used to non-invasively monitor time-resolved metabolite concentrations and to image the biomass volume and distribution. As a first illustration of the feasibility of the methodology an initial 13C-labeled lactate metabolic pathway study was performed, yielding results consistent with existing genomic data for MR-1. These results represent progress toward our ultimate goal of correlating time- and depth-resolved metabolism and mass transport with gene expression in live in situ biofilms using combined NMR/optical microscopy techniques.

  2. Mixing and Matching Detergents for Membrane Protein NMR Structure Determination

    SciTech Connect

    Columbus, Linda; Lipfert, Jan; Jambunathan, Kalyani; Fox, Daniel A.; Sim, Adelene Y.L.; Doniach, Sebastian; Lesley, Scott A.; (Stanford); (Scripps); (UV)

    2009-10-21

    One major obstacle to membrane protein structure determination is the selection of a detergent micelle that mimics the native lipid bilayer. Currently, detergents are selected by exhaustive screening because the effects of protein-detergent interactions on protein structure are poorly understood. In this study, the structure and dynamics of an integral membrane protein in different detergents is investigated by nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) spectroscopy and small-angle X-ray scattering (SAXS). The results suggest that matching of the micelle dimensions to the protein's hydrophobic surface avoids exchange processes that reduce the completeness of the NMR observations. Based on these dimensions, several mixed micelles were designed that improved the completeness of NMR observations. These findings provide a basis for the rational design of mixed micelles that may advance membrane protein structure determination by NMR.

  3. Portable pulsed NMR instrument and method of use

    SciTech Connect

    Brown, R. J. S.

    1984-10-30

    In accordance with the present invention, fluid-flow properties of a rock sample based on NMR response of the hydrogen nuclei of interstitial fluids within the pore space of such sample, can be swiftly and accurately achieved using a portable NMR instrument. Inherent instrument inadequacies (DC field inhomogeneity and large phase background jitter) are themselves relied upon to increase the data-throughput efficiency, i.e., the number of NMR responses performed per unit time. Result: Even though the instrument is placed at field sites away from the usual processing center, quick analysis of rock samples as during the drilling of a well, still results. Also, effects of possible echoes during subsequent measurements are prevented by using both the inhomogeneities of the DC field and the essentially random phase spectrum that is inherent in the instrument to average out echoes of prior generated NMR responses.

  4. Protein MAS NMR methodology and structural analysis of protein assemblies

    E-print Network

    Bayro, Marvin J

    2010-01-01

    Methodological developments and applications of solid-state magic-angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy, with particular emphasis on the analysis of protein structure, are described in this thesis. ...

  5. Investigation of porous media structures using NMR restricted diffusion measurements 

    E-print Network

    Miao, Peizhi

    1993-01-01

    of fluids contained in porous solids the measured value of dif- fusion coefficient is affected by the porous structure. If a pore structure charac- terization method can be developed using NMR diffusion measurements of fluids in porous media... represents the first known attempt to describe the restricted diffusion coefficient as a continuous function and extract the unknown function successfully from NMR restricted difFusion measurements. TO MY WIFE, XU vs ACKNOWLEDGEMENTS I sincerely thank...

  6. Structural Biology by NMR: Structure, Dynamics, and Interactions

    Microsoft Academic Search

    Phineus R. L. Markwick; Thérèse Malliavin; Michael Nilges

    2008-01-01

    The function of bio-macromolecules is determined by both their 3D structure and conformational dynamics. These molecules are inherently flexible systems displaying a broad range of dynamics on time-scales from picoseconds to seconds. Nuclear Magnetic Resonance (NMR) spectroscopy has emerged as the method of choice for studying both protein structure and dynamics in solution. Typically, NMR experiments are sensitive both to

  7. NMR elucidation of novel ligands derived from ( R )-(+)-camphor

    Microsoft Academic Search

    Grant A. Boyle; Thavendran Govender; Hendrik G. Kruger; Glenn E. M. Maguire

    2009-01-01

    The complete NMR elucidation of five camphor-derived ligands is reported. 2D NMR techniques such as NOESY are used to assist\\u000a in the determination of the orientation of the donor groups in space. The compounds were synthesized as ligands to be used\\u000a in asymmetric catalysis. They represent the first instance where both donor groups are pendant on the C3 position of

  8. NMR of molecules interacting with lipids in small unilamellar vesicles

    Microsoft Academic Search

    Grégory Da Costa; Liza Mouret; Soizic Chevance; Elisabeth Le Rumeur; Arnaud Bondon

    2007-01-01

    Detailed characterization of protein, peptide or drug interactions with natural membrane is still a challenge. This review\\u000a focuses on the use of nuclear magnetic resonance (NMR) for the analysis of interaction of molecules with small unilamellar\\u000a vesicles (SUV). These phospholipid vesicles are often used as model membranes for fluorescence or circular dichroism experiments.\\u000a The various NMR approaches for studying molecule-lipid

  9. Deuterium incorporation in biomass cell wall components by NMR analysis.

    PubMed

    Foston, Marcus B; McGaughey, Joseph; O'Neill, Hugh; Evans, Barbara R; Ragauskas, Arthur

    2012-03-01

    A commercially available deuterated kale sample was analyzed for deuterium incorporation by ionic liquid solution (2)H and (1)H nuclear magnetic resonance (NMR). This protocol was found to effectively measure the percent deuterium incorporation at 33%, comparable to the 31% value determined by combustion. The solution NMR technique also suggested by a qualitative analysis that deuterium is preferentially incorporated into the carbohydrate components of the kale sample. PMID:22223179

  10. Complete NMR characterization of lychnose from Stellaria media (L.) Vill

    Microsoft Academic Search

    Mieke Vanhaecke; Wim Van den Ende; André Van Laere; Piet Herdewijn; Eveline Lescrinier

    2006-01-01

    Lychnose (?-d-Gal-(1?6)-?-d-Glc-(1?2)-?-d-Fru-(1?1)-?-d-Gal) was isolated from Stellaria media, a representative member of the Caryophyllaceae plant family. Weak acid hydrolysis, enzymatic hydrolysis and complete NMR characterization were performed to confirm the identity of the tetrasaccharide. All 1H and 13C resonances were unambiguously assigned and the conformation of the sugars was determined using one and two dimensional NMR techniques. Anomeric characterizations in lychnose

  11. Functional cerebral imaging by susceptibility-contrast NMR

    Microsoft Academic Search

    J. W. Belliveau; B. R. Rosen; H. L. Kantor; R. R. Rzedzian; D. N. Kennedy; R. C. McKinstry; J. M. Vevea; M. S. Cohen; I. L. Pykett; T. J. Brady

    1990-01-01

    In vivo measurement of cerebral physiology by dynamic contrast-enhanced NMR is demonstrated. Time-resolved images of the cerebral transit of paramagnetic contrast agent were acquired using a new ultrafast NMR imaging technique and a novel mechanism of image contrast based on microscopic changes in tissue magnetic susceptibility. Global hypercapnia in dogs was used to establish the relationship between susceptibility-induced signal change

  12. NMR and DSC studies during thermal denaturation of collagen

    Microsoft Academic Search

    Abderrahim Rochdi; Jean-Pierre Renou

    2000-01-01

    Epimysial and intramuscular connective tissues from calf and cow muscle were studied by NMR and DSC. Water proton NMR transverse relaxation times (T2) were measured at 10°C for both native and thermally-denatured at 90°C for 30–360 min. DSC measurements were used to determine the temperature and the variation enthalpy of sol?gel transition. According to the heating time, significant differences were

  13. NMR relaxometry and differential scanning calorimetry during meat cooking

    Microsoft Academic Search

    Hanne Christine Bertram; Zhiyun Wu; Frans van den Berg; Henrik J. Andersen

    2006-01-01

    By combining simultaneous nuclear magnetic resonance (NMR) T2 relaxometry and differential scanning calorimetry (DSC) on pork samples heated to nine temperature levels between 25 and 75°C, the present study investigates the relationship between thermal denaturation of meat proteins and heat-induced changes in water characteristics. Principal component analysis (PCA) on the distributed 1H NMR T2 relaxation data revealed that the major

  14. INTRODUCTION TO NMR AND ITS APPLICATION IN METABOLITE

    E-print Network

    Powers, Robert

    for structure characterization of organic molecules, 13 C, 15 N, 31 P, and 19 F NMR spectra are also commonly.108 6.7283 150.864 15 N 1/2 0.37 À2.712 60.798 19 F 1/2 100 25.181 564.462 31 P 1/2 100 10.841 24212 INTRODUCTION TO NMR AND ITS APPLICATION IN METABOLITE STRUCTURE DETERMINATION XIAOHUA HUANG

  15. New applications of laser-polarized noble gas NMR

    Microsoft Academic Search

    R. L. Walsworth

    1999-01-01

    Laser optical pumping techniques greatly enhance the NMR detection sensitivity of the spin 1\\/2 noble gases (3He and 129Xe), with novel applications in both the biomedical and physical sciences. I will discuss new research activities by my group and collaborators using laser polarized noble gas NMR: gas-space imaging at both high and low magnetic fields; imaging of liquid xenon and

  16. NMR enantiodifferentiation of quaternary ammonium salts of Tröger base.

    PubMed

    Michon, Christophe; Gonçalves-Farbos, Maria-Héléna; Lacour, Jérôme

    2009-10-01

    Hexacoordinated phosphorus BINPHAT anion 1 is an efficient NMR chiral solvating agent for quaternary ammonium cations (quats) derived from Tröger base leading to large separations of the proton signals of the enantiomers and even in polar solvent media such as CD(3)CN (Delta Delta delta up to 0.12 ppm). Quite surprisingly, this efficacy in the NMR split efficiency is not translated into a supramolecular stereocontrol (Pfeiffer effect) of the cation configuration by the anion. PMID:19161219

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

    SciTech Connect

    Hirasaki, George J.; Mohanty, Kishore K.

    2003-02-10

    The objective of this project was to characterize the fluid properties and fluid-rock interactions which are needed for formation evaluation by NMR well logging. NMR well logging is finding wide use in formation evaluation. The formation parameters commonly estimated were porosity, permeability, and capillary bound water. Special cases include estimation of oil viscosity, residual oil saturation, location of oil/water contact, and interpretation on whether the hydrocarbon is oil or gas.

  18. 31 P NMR Investigation of vanadium-treated chick muscle

    Microsoft Academic Search

    C. Tyler Burt; Benjamin Chen; C. H. Hill

    1991-01-01

    The phosphorus NMR profile of normal and vanadium-treated chick muscle was obtained in vivo. The data show that the differentiation\\u000a of breast and thigh muscles in terms of pH, lipid related metabolites, and bioenergetic parameters can be readily followed.\\u000a Although the vanadium-treated chicks showed substantial retardation of growth, the only NMR parameter that was significanty\\u000a affected by dietary vanadium was

  19. Permeability Prediction for Low Porosity Rocks by Mobile NMR

    Microsoft Academic Search

    H. Pape; J. Arnold; R. Pechnig; C. Clauser; E. Talnishnikh; S. Anferova; B. Blümich

    2009-01-01

    Estimating permeability from NMR well logs or mobile NMR core scanner data is an attractive method as the measurements can\\u000a be performed directly in the formation or on fresh cores right after drilling. Furthermore, the method is fast and non-destructive.\\u000a Compared to T1 relaxation times, commonly measured T2 distributions are influenced by external and internal magnetic field gradients. We performed

  20. Recent progress in NMR\\/MRI in petroleum applications

    Microsoft Academic Search

    Yi-Qiao Song

    2007-01-01

    NMR has become an important technique for characterization of porous materials. In particular, its importance in petroleum exploration has been enhanced by the recent progress in NMR well-logging techniques and instruments. Such advanced techniques are increasing being accepted as a valuable service especially in deep-sea exploration. This paper will outline the recent progress of MR techniques at Schlumberger-Doll Research. Well-logging

  1. Analysis and optimization of NMR sensor for oilfield exploration applications

    Microsoft Academic Search

    Jaideva C. Goswami; Bruno Luong

    2000-01-01

    Nuclear magnetic resonance (NMR) measurements have become an important part of oilfield well-logging to identify and quantify oil and gas reservoirs. In this paper, some design aspects of NMR sensor for well-logging applications are discussed. The RF and static magnetic fields are computed using a 3D finite element method (FEM). A perturbation technique along with FEM is used to evaluate

  2. Mobile NMR for geophysical analysis and materials testing

    Microsoft Academic Search

    Bernhard Blümich; Jörg Mauler; Agnes Haber; Juan Perlo; Ernesto Danieli; Federico Casanova

    2009-01-01

    Initiated by well logging NMR, portable NMR instruments are being developed for a variety of novel applications in materials\\u000a testing, process analysis and control, which provides new opportunities for geophysical investigations. Small-diameter cylindrical\\u000a sensors can probe short distances into the walls of slim-line logging holes, and single-sided sensors enable non-destructive\\u000a testing of large objects. Both sensors are characterized by small

  3. Permeability Prediction for Low Porosity Rocks by Mobile NMR

    Microsoft Academic Search

    H. Pape; J. Arnold; R. Pechnig; C. Clauser; E. Talnishnikh; S. Anferova; B. Blümich

    Estimating permeability from NMR well logs or mobile NMR core scanner data is an attractive method as the measurements can\\u000a be performed directly in the formation or on fresh cores right after drilling. Furthermore, the method is fast and non-destructive.\\u000a Compared to T\\u000a 1 relaxation times, commonly measured T\\u000a 2 distributions are influenced by external and internal magnetic field gradients.

  4. 1 H NMR metabolic fingerprinting of saffron extracts

    Microsoft Academic Search

    Ali Yilmaz; Nils T. Nyberg; Per Mølgaard; Javad Asili; Jerzy W. Jaroszewski

    2010-01-01

    The aim of this study was to explore feasibility of 1H NMR metabolic fingerprinting for discrimination of authenticity of saffron using principal component analysis (PCA) modeling.\\u000a Authentic reference Iranian saffron (n = 31) and commercial samples (n = 32) were used. Cross-validated PCA models based on 1H NMR spectra of solutions prepared by direct extraction of grinded saffron with methanol-d\\u000a 4 distinguished reference Iranian

  5. 15N NMR of 1,4-dihydropyridine derivatives.

    PubMed

    Goba, Inguna; Liepinsh, Edvards

    2013-07-01

    In this article, we describe the characteristic (15)N and (1)HN NMR chemical shifts and (1)J((15)N-(1)H) coupling constants of various symmetrically and unsymmetrically substituted 1,4-dihydropyridine derivatives. The NMR chemical shifts and coupling constants are discussed in terms of their relationship to structural features such as character and position of the substituent in heterocycle, N-alkyl substitution, nitrogen lone pair delocalization within the conjugated system, and steric effects. PMID:23696534

  6. Ultrafast high-resolution magic-angle-spinning NMR spectroscopy.

    PubMed

    André, Marion; Piotto, Martial; Caldarelli, Stefano; Dumez, Jean-Nicolas

    2015-06-21

    We demonstrate the acquisition of ultrafast 2D NMR spectra of semi-solid samples, with a high-resolution magic-angle-spinning setup. Using a recent double-quantum NMR pulse sequence in optimised synchronisation conditions, high-quality 2D spectra can be recorded for a sample under magic-angle spinning. An illustration is given with a semi-solid sample of banana pulp. PMID:25946235

  7. The development of solid-state NMR of membrane proteins

    PubMed Central

    Opella, Stanley J.

    2014-01-01

    Most biological functions are carried out in supramolecular assemblies. As a result of their slow reorientation in solution, these assemblies have been resistant to the widely employed solution NMR approaches. The development of solid-state NMR to first of all overcome the correlation time problem and then obtain informative high-resolution spectra of proteins in supramolecular assemblies, such as virus particles and membranes, is described here. High resolution solid-state NMR is deeply intertwined with the history of NMR, and the seminal paper was published in 1948. Although the general principles were understood by the end of the 1950s, it has taken more than fifty years for instrumentation and experimental methods to become equal to the technical problems presented by the biological assemblies of greatest interest. It is now possible to obtain atomic resolution structures of viral coat proteins in virus particles and membrane proteins in phospholipid bilayers by oriented sample solid-state NMR methods. The development of this aspect of the field of solid-state NMR is summarized in this review article.

  8. Nanoscale NMR spectroscopy and imaging of multiple nuclear species.

    PubMed

    DeVience, Stephen J; Pham, Linh M; Lovchinsky, Igor; Sushkov, Alexander O; Bar-Gill, Nir; Belthangady, Chinmay; Casola, Francesco; Corbett, Madeleine; Zhang, Huiliang; Lukin, Mikhail; Park, Hongkun; Yacoby, Amir; Walsworth, Ronald L

    2015-02-01

    Nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) provide non-invasive information about multiple nuclear species in bulk matter, with wide-ranging applications from basic physics and chemistry to biomedical imaging. However, the spatial resolution of conventional NMR and MRI is limited to several micrometres even at large magnetic fields (>1?T), which is inadequate for many frontier scientific applications such as single-molecule NMR spectroscopy and in vivo MRI of individual biological cells. A promising approach for nanoscale NMR and MRI exploits optical measurements of nitrogen-vacancy (NV) colour centres in diamond, which provide a combination of magnetic field sensitivity and nanoscale spatial resolution unmatched by any existing technology, while operating under ambient conditions in a robust, solid-state system. Recently, single, shallow NV centres were used to demonstrate NMR of nanoscale ensembles of proton spins, consisting of a statistical polarization equivalent to ?100-1,000 spins in uniform samples covering the surface of a bulk diamond chip. Here, we realize nanoscale NMR spectroscopy and MRI of multiple nuclear species ((1)H, (19)F, (31)P) in non-uniform (spatially structured) samples under ambient conditions and at moderate magnetic fields (?20?mT) using two complementary sensor modalities. PMID:25559712

  9. Conjoined use of EM and NMR in RNA structure refinement.

    PubMed

    Gong, Zhou; Schwieters, Charles D; Tang, Chun

    2015-01-01

    More than 40% of the RNA structures have been determined using nuclear magnetic resonance (NMR) technique. NMR mainly provides local structural information of protons and works most effectively on relatively small biomacromolecules. Hence structural characterization of large RNAs can be difficult for NMR alone. Electron microscopy (EM) provides global shape information of macromolecules at nanometer resolution, which should be complementary to NMR for RNA structure determination. Here we developed a new energy term in Xplor-NIH against the density map obtained by EM. We conjointly used NMR and map restraints for the structure refinement of three RNA systems—U2/U6 small-nuclear RNA, genome-packing motif (?(CD))2 from Moloney murine leukemia virus, and ribosome-binding element from turnip crinkle virus. In all three systems, we showed that the incorporation of a map restraint, either experimental or generated from known PDB structure, greatly improves structural precision and accuracy. Importantly, our method does not rely on an initial model assembled from RNA duplexes, and allows full torsional freedom for each nucleotide in the torsion angle simulated annealing refinement. As increasing number of macromolecules can be characterized by both NMR and EM, the marriage between the two techniques would enable better characterization of RNA three-dimensional structures. PMID:25798848

  10. Multidimensional spatial-spectral holographic interpretation of NMR photography.

    PubMed

    Kiruluta, Andrew J M

    2006-05-21

    A spectral holographic interpretation arises naturally in nuclear magnetic resonance (NMR) photography from either the intrinsic chemical shift anisotropy of the spin system or the field inhomogeneity due to the applied spatial encoding gradients. We can thus think of NMR photography as arising from a "diffraction" off a spatial-spectral holographic grating. The spatial holographic component arises from a high dielectric constant (>50) of the NMR medium at high field strength (>4 T) when the excitation wavelength is commensurate with the size of the NMR sample; otherwise, it is a volume spectral holographic grating. In this paper, the NMR localized spectroscopy (imaging) equation is derived from the principles of spatial-spectral holography. Holographic properties of storage and programmable time delay and time reversal are shown to follow naturally from this viewpoint and are experimentally demonstrated in an inhomogeneously broadened NMR sample. These ideas are shown to be extendable to complex signal processing functions such as recognition, correlations, and triple products. PMID:16729804

  11. SPINS: Standardized ProteIn NMR Storage. A data dictionary and object-oriented relational database for archiving protein NMR spectra

    Microsoft Academic Search

    Michael C. Baran; Hunter N. B. Moseley; Gurmukh Sahota; Gaetano T. Montelione

    2002-01-01

    Modern protein NMR spectroscopy laboratories have a rapidly growing need for an easily queried local archival system of raw\\u000a experimental NMR datasets. SPINS (Standardized ProteIn Nmr Storage) is an object-oriented relational database that provides facilities for high-volume NMR data archival, organization\\u000a of analyses, and dissemination of results to the public domain by automatic preparation of the header files required for

  12. Improvements in Technique of NMR Imaging and NMR Diffusion Measurements in the Presence of Background Gradients.

    NASA Astrophysics Data System (ADS)

    Lian, Jianyu

    In this work, modification of the cosine current distribution rf coil, PCOS, has been introduced and tested. The coil produces a very homogeneous rf magnetic field, and it is inexpensive to build and easy to tune for multiple resonance frequency. The geometrical parameters of the coil are optimized to produce the most homogeneous rf field over a large volume. To avoid rf field distortion when the coil length is comparable to a quarter wavelength, a parallel PCOS coil is proposed and discussed. For testing rf coils and correcting B _1 in NMR experiments, a simple, rugged and accurate NMR rf field mapping technique has been developed. The method has been tested and used in 1D, 2D, 3D and in vivo rf mapping experiments. The method has been proven to be very useful in the design of rf coils. To preserve the linear relation between rf output applied on an rf coil and modulating input for an rf modulating -amplifying system of NMR imaging spectrometer, a quadrature feedback loop is employed in an rf modulator with two orthogonal rf channels to correct the amplitude and phase non-linearities caused by the rf components in the rf system. The modulator is very linear over a large range and it can generate an arbitrary rf shape. A diffusion imaging sequence has been developed for measuring and imaging diffusion in the presence of background gradients. Cross terms between the diffusion sensitizing gradients and background gradients or imaging gradients can complicate diffusion measurement and make the interpretation of NMR diffusion data ambiguous, but these have been eliminated in this method. Further, the background gradients has been measured and imaged. A dipole random distribution model has been established to study background magnetic fields Delta B and background magnetic gradients G_0 produced by small particles in a sample when it is in a B_0 field. From this model, the minimum distance that a spin can approach a particle can be determined by measuring and <{bf G}_sp{0 }{2}>. From this model, the particle concentration in a sample can be determined by measuring the lineshape of a free induction decay (fid).

  13. Automated protein NMR structure determination in solution.

    PubMed

    Gronwald, Wolfram; Kalbitzer, Hans Robert

    2010-01-01

    The main drawback of protein NMR spectroscopy today is still the extensive amount of time required for solving a single structure. The main bottleneck in this respect is the manual evaluation of the experimental spectra. A clear solution to this challenge is the development of automated methods for this purpose. At the current stage of development, this goal has been almost or in a few cases fully reached for favorable cases such as well-behaved, stably folding smaller proteins below the 25 kDa range. For larger and/or more difficult molecules, the input of a human expert is still required. However, even here, automated routines will substantially speed up the structure determination process. In this report, we will summarize recent developments in this field and especially emphasize practical aspects important for a successful automated protein structure determination in solution. An important aspect closely related to structure determination is structure validation. Therefore, we devote a section to automated approaches for this topic. PMID:20835795

  14. Variable temperature NMR characterization of ?-glycine

    NASA Astrophysics Data System (ADS)

    Taylor, R. E.; Dybowski, C.

    2008-10-01

    Proton NMR spin-lattice relaxation times in the laboratory frame ( T1) and in the rotating frame ( T1?) were measured as a function of temperature for a static sample of ?-glycine. Both T1 and T1? data can be fit quantitatively by a single thermally-activated motion (the modulation of the dipolar coupling by random hopping about the threefold axis of the -NH 3 group), with no addition of other mechanisms at any temperature between 173 and 415 K. An activation energy of 21.7 ± 1 kJ/mol was extracted and is compared with previously reported values for both ?- and ?-glycine. Such comparisons allow the correction of glycine polymorphs misidentified in the literature. The minimum in T1 at 325 K corresponds to a correlation time of 0.53 ns. Chemical shifts as a function of temperature were measured by 1H CRAMPS and by 13C and 15N CP/MAS experiments. These results are discussed relative to a previous report of anomalous electrical behavior in ?-glycine within this temperature range.

  15. Improving NMR and MRI sensitivity with parahydrogen.

    PubMed

    Duckett, Simon B; Mewis, Ryan E

    2013-01-01

    Parahydrogen induced polarisation (PHIP) has wide utility in NMR and MRI as it can increase the sensitivity of both techniques. The transfer of spin order from parahydrogen to nuclei in the analyte leads to an increased magnetic response following interrogation by RF pulses. This spin transfer is catalysed by a homogeneous or heterogeneous catalyst. The increased magnetic response not only reduces the number of transients required to obtain the spectrum or image, but can also illuminate previously undetectable species present in solution. From its theoretical prediction to its experimental validation, PHIP has been applied in a range of different areas such as the structural analysis of complexes, understanding reaction mechanisms involving hydrogen and for the production of contrast agents for use in MRI. PHIP can also be readily combined with other techniques such as photochemistry which widens its field of applicability. In this review, we detail the properties of parahydrogen and the methods for its preparation and utilisation in homogeneous and heterogeneous based hydrogenation and non-hydrogenative reactions. Specific examples are explained for the application of PHIP in photochemical and hydroformylation reactions. Pulse sequences designed to be compatible with PHIP are described to exemplify how the increase in sensitivity can be increased even further by the interrogation of the magnetic states optimally. Finally, a section on the use of PHIP in the production of contrast agents suitable for MRI, and the monitoring of hydrogenation reactions using imaging techniques is discussed. PMID:23138689

  16. SPINS: standardized protein NMR storage. A data dictionary and object-oriented relational database for archiving protein NMR spectra.

    PubMed

    Baran, Michael C; Moseley, Hunter N B; Sahota, Gurmukh; Montelione, Gaetano T

    2002-10-01

    Modern protein NMR spectroscopy laboratories have a rapidly growing need for an easily queried local archival system of raw experimental NMR datasets. SPINS (Standardized ProteIn Nmr Storage) is an object-oriented relational database that provides facilities for high-volume NMR data archival, organization of analyses, and dissemination of results to the public domain by automatic preparation of the header files required for submission of data to the BioMagResBank (BMRB). The current version of SPINS coordinates the process from data collection to BMRB deposition of raw NMR data by standardizing and integrating the storage and retrieval of these data in a local laboratory file system. Additional facilities include a data mining query tool, graphical database administration tools, and a NMRStar v2. 1.1 file generator. SPINS also includes a user-friendly internet-based graphical user interface, which is optionally integrated with Varian VNMR NMR data collection software. This paper provides an overview of the data model underlying the SPINS database system, a description of its implementation in Oracle, and an outline of future plans for the SPINS project. PMID:12495027

  17. Whole-core analysis by sup 13 C NMR

    SciTech Connect

    Vinegar, H.J.; Tutunjian, P.N. (Shell Development Co. (US)); Edelstein, W.A.; Roemer, P.B. (General Electric Corp. (US))

    1991-06-01

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

  18. NMR Study of Strontium Binding by a Micaceous Mineral

    SciTech Connect

    Bowers, Geoffrey M.; Ravella, Ramesh; Komarneni, S.; Mueller, Karl T.

    2006-04-13

    The nature of strontium binding by soil minerals directly affects the transport and sequestration/remediation of radioactive strontium species released from leaking high-level nuclear waste storage tanks. However, the molecular-level structure of strontium binding sites has seldom been explored in phyllosilicate minerals by direct spectroscopic means and is not well-understood. In this work, we use solid-state NMR to analyze strontium directly and indirectly in a fully strontium-exchanged synthetic mica of nominal composition Na4Mg6Al4Si4O20F4. Thermogravimetric analysis, X-ray diffraction analysis, and NMR evidence supports that heat treatment at 500 °C for 4 h fully dehydrates the mica, creating a hydrogen-free interlayer. Analysis of the strontium NMR spectrum of the heat-treated mica shows a single strontium environment with a quadrupolar coupling constant of 9.02 MHz and a quadrupolar asymmetry parameter of 1.0. These quadrupolar parameters are consistent with a highly distorted and asymmetric coordination environment that would be produced by strontium cations without water in the coordination sphere bound deep within the ditrigonal holes. Evidence for at least one additional strontium environment, where proton-strontium couplings may occur, was found via a 1H-87Sr transfer of populations by double resonance NMR experiment. We conclude that the strontium cations in the proton-free interlayer are observable by 87Sr NMR and bound through electrostatic interactions as nine coordinate inner-sphere complexes sitting in the ditrigonal holes. Partially hydrated strontium cations invisible to direct 87Sr NMR are also present and located on the external mica surfaces, which are known to hydrate upon exposure to atmospheric moisture. These results demonstrate that modern pulsed NMR techniques and high fields can be used effectively to provide structural details of strontium binding by phyllosilicate minerals.

  19. Accurate, fully-automated NMR spectral profiling for metabolomics.

    PubMed

    Ravanbakhsh, Siamak; Liu, Philip; Bjordahl, Trent C; Mandal, Rupasri; Grant, Jason R; Wilson, Michael; Eisner, Roman; Sinelnikov, Igor; Hu, Xiaoyu; Luchinat, Claudio; Greiner, Russell; Wishart, David S

    2015-01-01

    Many diseases cause significant changes to the concentrations of small molecules (a.k.a. metabolites) that appear in a person's biofluids, which means such diseases can often be readily detected from a person's "metabolic profile"-i.e., the list of concentrations of those metabolites. This information can be extracted from a biofluids Nuclear Magnetic Resonance (NMR) spectrum. However, due to its complexity, NMR spectral profiling has remained manual, resulting in slow, expensive and error-prone procedures that have hindered clinical and industrial adoption of metabolomics via NMR. This paper presents a system, BAYESIL, which can quickly, accurately, and autonomously produce a person's metabolic profile. Given a 1D 1H NMR spectrum of a complex biofluid (specifically serum or cerebrospinal fluid), BAYESIL can automatically determine the metabolic profile. This requires first performing several spectral processing steps, then matching the resulting spectrum against a reference compound library, which contains the "signatures" of each relevant metabolite. BAYESIL views spectral matching as an inference problem within a probabilistic graphical model that rapidly approximates the most probable metabolic profile. Our extensive studies on a diverse set of complex mixtures including real biological samples (serum and CSF), defined mixtures and realistic computer generated spectra; involving > 50 compounds, show that BAYESIL can autonomously find the concentration of NMR-detectable metabolites accurately (~ 90% correct identification and ~ 10% quantification error), in less than 5 minutes on a single CPU. These results demonstrate that BAYESIL is the first fully-automatic publicly-accessible system that provides quantitative NMR spectral profiling effectively-with an accuracy on these biofluids that meets or exceeds the performance of trained experts. We anticipate this tool will usher in high-throughput metabolomics and enable a wealth of new applications of NMR in clinical settings. BAYESIL is accessible at http://www.bayesil.ca. PMID:26017271

  20. Accurate, Fully-Automated NMR Spectral Profiling for Metabolomics

    PubMed Central

    Ravanbakhsh, Siamak; Liu, Philip; Bjordahl, Trent C.; Mandal, Rupasri; Grant, Jason R.; Wilson, Michael; Eisner, Roman; Sinelnikov, Igor; Hu, Xiaoyu; Luchinat, Claudio; Greiner, Russell; Wishart, David S.

    2015-01-01

    Many diseases cause significant changes to the concentrations of small molecules (a.k.a. metabolites) that appear in a person’s biofluids, which means such diseases can often be readily detected from a person’s “metabolic profile"—i.e., the list of concentrations of those metabolites. This information can be extracted from a biofluids Nuclear Magnetic Resonance (NMR) spectrum. However, due to its complexity, NMR spectral profiling has remained manual, resulting in slow, expensive and error-prone procedures that have hindered clinical and industrial adoption of metabolomics via NMR. This paper presents a system, BAYESIL, which can quickly, accurately, and autonomously produce a person’s metabolic profile. Given a 1D 1H NMR spectrum of a complex biofluid (specifically serum or cerebrospinal fluid), BAYESIL can automatically determine the metabolic profile. This requires first performing several spectral processing steps, then matching the resulting spectrum against a reference compound library, which contains the “signatures” of each relevant metabolite. BAYESIL views spectral matching as an inference problem within a probabilistic graphical model that rapidly approximates the most probable metabolic profile. Our extensive studies on a diverse set of complex mixtures including real biological samples (serum and CSF), defined mixtures and realistic computer generated spectra; involving > 50 compounds, show that BAYESIL can autonomously find the concentration of NMR-detectable metabolites accurately (~ 90% correct identification and ~ 10% quantification error), in less than 5 minutes on a single CPU. These results demonstrate that BAYESIL is the first fully-automatic publicly-accessible system that provides quantitative NMR spectral profiling effectively—with an accuracy on these biofluids that meets or exceeds the performance of trained experts. We anticipate this tool will usher in high-throughput metabolomics and enable a wealth of new applications of NMR in clinical settings. BAYESIL is accessible at http://www.bayesil.ca. PMID:26017271

  1. Use of nitroxides as NMR contrast enhancing agents for joints.

    PubMed

    Pou, S; Davis, P L; Wolf, G L; Rosen, G M

    1995-10-01

    NMR imaging is a well-established technology for obtaining cross-sectional anatomic pictures of organs and tissues. In addition, NMR can provide valuable information about the physiologic state of organs and tissues, especially, as a consequence of cellular injury. With this in mind, NMR in combination with gadolinium-based contrast enhancing agents has been used to assist in the detection of abnormalities to joints as well as to evaluate the status of damage resulting from an injury to this site. We describe the synthesis of a new nitroxide, which is bioresistant to the one-electron reduction mediated by superoxide in the presence of cysteine. This model mimics the reduction of nitroxides by extracellular secretion of superoxide by PMA-stimulated neutrophils. With this nitroxide, we found, in the range from 15 to 17.5 mumoles, enhancement of an NMR image in the knee joint of rabbits. Of interest is the finding that the contrast image remained for at least 90 minutes. These results demonstrate the utility of nitroxides as contrast enhancing agents for NMR imaging of joints. PMID:7493041

  2. NMR investigations of gas transport in fluidized beds

    NASA Astrophysics Data System (ADS)

    Wang, R.; Ng, J.; Rosen, M.; Mair, R.; Walsworth, R.; Candela, D.

    2004-03-01

    We are using NMR of hyperpolarized xenon to study gas transport in fluidized beds. Our preliminary investigations have shown that both the xenon NMR frequency and linewidth are dependent on the bulk gas flow rate through the bed; and that a distinct xenon NMR frequency spectral peak can be observed in the bubbling regime. These changes of the xenon NMR frequency spectrum are caused by differences in local magnetic susceptibility gradients for gas in the bubble and interstitial phases, due to different grain number densities in the two phases. We have also performed preliminary pulsed-field-gradient NMR studies of the xenon gas displacement probability as a function of time, which yields the vertical gas-flow velocity distribution through the fluidized bed. For low gas-flow, such that the granular sample remains static or homogeneously-fluidized, we find that the measured velocity distribution is Gaussian, which suggests coherent gas-flow through the bed. At the onset of bubbling, the emergence of more complicated gas-flow becomes apparent: the velocity distribution broadens considerably, and a significant fraction of the gas has a negative velocity. These measurements are consistent with a picture of gas in bubbles rising through the fluidized bed, while some interstitial-phase gas flows down in the reverse direction through the pack.

  3. NMR study of the potential composition of Titan's lakes

    NASA Astrophysics Data System (ADS)

    He, Chao; Smith, Mark A.

    2015-05-01

    A large number of hydrocarbon lakes have been discovered in Titan's surface. However, the chemical composition and physical properties of these lakes are not fully understood. We investigate the potential composition of Titan's lakes by NMR. Based upon NMR data, the 1H and 13C NMR spectra of the hydrocarbons in Titan's lakes are simulated on a 1 T spectrometer [being developed at the NASA Jet Propulsion Laboratory (JPL) for future in situ characterization of Titan's lakes]. The study indicates that the dominant composition (all components>1% of the lake composition by mole fraction) in Titan's lakes can be determined and the major soluble organics quantitatively identified from either quantitative 1H or 13C spectra on a 1 T NMR spectrometer. The proton T1 relaxation times are determined for a number of candidate organics in hydrocarbon solution, a necessary determinant for quantitative NMR. The gas solubility of these organics is also investigated to understand the equilibrium of composition between Titan's lakes and atmosphere and the precipitation rates of the molecules at Titan's ground level. Our results are significant for the ongoing discussion regarding the development of in situ, low bias analysis methods and instruments for Titan missions and other outer planet exploration.

  4. Study of cultured fibroblasts in vivo using NMR

    SciTech Connect

    Karczmar, G.S.

    1984-08-01

    The goal was to study the compartmentation of phosphorylated glycolytic intermediates in intact Chicken Embryo Fibroblasts (CEFs) using /sup 31/P NMR at 109 MHz. A technique for maintaining functional cells at high densities in an NMR magnet is described. Signals were detected from cytoplasmic inorganic phosphate (P/sub i/), ATP, NAD, NADH, phosphorylcholine and phosphorylethanolamine. The effect of external glucose on cytoplasmic pools of phosphates was studied. When cells were perfused with glucose-free medium the rate of glycolysis decreased, the amplitudes of the ATP resonances decreased, and the P/sub i/ intensity increased. The quantity of NMR-detectable P/sub i/ produced was significantly greater than the quantity of NMR-detectable ATP which was lost. Experiments with /sup 32/P labeled P/sub i/ showed that as the concentration of glucose in the medium was increase, the amount of phosphate sequestered in the cells increased. We conclude that there is a pool of P/sub i/ which is not detected by high resolution NMR and that the size of this pool increases as the rate of glycolysis increase. Longtitudinal relaxation times of intracellular phosphates in normal, transformed, and primary CEFs were measured. The results demonstrate that relaxation times of phosphates are sensitive to structural and metabolic changes which occur when cells are grown in culture. 59 references. 31 figures.

  5. Nonlinear Identification of NMR Spin Systems by Adaptive Filtering

    NASA Astrophysics Data System (ADS)

    Asfour, Aktham; Raoof, Kosai; Fournier, Jean-Marc

    2000-07-01

    In this paper, we present two new methods for identifying NMR spin systems. These methods are based on nonlinear adaptive filtering. The spin system is assumed to be time-invariant with memory. The first method uses a truncated discrete Volterra series to describe the nonlinear relationship between excitation (input) and system response (output). First-, second-, and third-order kernels of this series are estimated employing the least mean square (LMS) algorithm. Three parallel filters can then model the NMR spin system so that its output is no more than simple sum of three convolution products between combinations of the input signal and filters coefficients. It is also shown that the contribution of the Volterra second-order term to the total system response is neglected compared with the contributions of the first- and the third-order terms. In the second identification method, the output signal is related to the input signal through a recursive nonlinear difference equation with constant coefficients. The LMS algorithm is used again to estimate the equation coefficients. The two methods are validated with a simulated NMR system model based on Bloch equations. The results and the performances of these methods are analyzed and compared. It is shown that our methods permit a simple identification of NMR spin systems. The field of applications of this study is promising in the optimization of NMR signal detection, especially in the cases of low signal-to-noise ratios where optimum signal filtering and analysis must be performed.

  6. NMR of a Phospholipid: Modules for Advanced Laboratory Courses

    NASA Astrophysics Data System (ADS)

    Gaede, Holly C.; Stark, Ruth E.

    2001-09-01

    A laboratory project is described that builds upon the NMR experience undergraduates receive in organic chemistry with a battery of NMR experiments that investigate egg phosphatidylcholine (egg PC). This material, often labeled in health food stores as lecithin, is a major constituent of mammalian cell membranes. The NMR experiments may be used to make resonance assignments, to study molecular organization in model membranes, to test the effects of instrumental parameters, and to investigate the physics of nuclear spin systems. A suite of modular NMR exercises is described, so that the instructor may tailor the laboratory sessions to biochemistry, instrumental analysis, or physical chemistry. The experiments include solution-state one-dimensional (1D) 1H, 13C, and 31P experiments; two-dimensional (2D) TOtal Correlated SpectroscopY (TOCSY); and the spectral editing technique of Distortionless Enhancement by Polarization Transfer (DEPT). To demonstrate the differences between solution and solid-state NMR spectroscopy and instrumentation, a second set of experiments generates 1H, 13C, and 31P spectra of egg PC dispersed in aqueous solution, under both static and magic-angle spinning conditions.

  7. Determination of fat content in NMR images of meat

    NASA Astrophysics Data System (ADS)

    Ballerini, Lucia

    2000-12-01

    In this paper we present an application to food science of image processing technique. We describe a method for determining fat content in beef meat. The industry of meat faces a permanent need for improved methods for meat quality evaluation. Researchers want improved techniques to deepen their understanding of meat features. Expectations of consumers for meat quality grow constantly, which induces the necessity of quality control. Recent advances in the area of computer and video processing have created new ways to monitor quality in the food industry. We investigate the use of a new technology to control the quality of food: NMR imaging. The inherent advantages of NMR images are many. Chief among these unprecedented contrasts between the various structures present in meat like muscle, fat, and connective tissue. Moreover, the three-dimensional nature of the NMR method allow us to analyze isolated cross-sectional slices of the meat and to measure the volumetric content of fat, not only the fat visible on the surface. We propose a segmentation algorithm for the detection of fat together with a filtering technique to remove intensity inhomogeneities in NMR images caused by non-uniformities of the magnetic field during acquisition. Measurements have been successfully correlated with chemical analysis and digital photography. Results show that the NMR technique is a promising non-invasive method to determine the fat content in meat.

  8. Sensitive and robust electrophoretic NMR: instrumentation and experiments.

    PubMed

    Hallberg, Fredrik; Furó, István; Yushmanov, Pavel V; Stilbs, Peter

    2008-05-01

    Although simple as a concept, electrophoretic NMR (eNMR) has so far failed to find wider application. Problems encountered are mainly due to disturbing and partly irreproducible convection-like bulk flow effects from both electro-osmosis and thermal convection. Additionally, bubble formation at the electrodes and rf noise pickup has constrained the typical sample geometry to U-tube-like arrangements with a small filling factor and a low resulting NMR sensitivity. Furthermore, the sign of the electrophoretic mobility cancels out in U-tube geometries. We present here a new electrophoretic sample cell based on a vertically placed conventional NMR sample tube with bubble-suppressing palladium metal as electrode material. A suitable radiofrequency filter design prevents noise pickup by the NMR sample coil from the high-voltage leads which extend into the sensitive sample volume. Hence, the obtained signal-to-noise ratio of this cell is one order of magnitude higher than that of our previous U-tube cells. Permitted by the retention of the sign of the displacement-related signal phase in the new cell design, an experimental approach is described where bulk flow effects by electro-osmosis and/or thermal convection are compensated through parallel monitoring of a reference signal from a non-charged species in the sample. This approach, together with a CPMG-like pulse train scheme provides a superior first-order cancellation of non-electrophoretic bulk flow effects. PMID:18289894

  9. Applications of toroids in high-pressure NMR spectroscopy

    SciTech Connect

    Klingler, R.J.; Rathke, J.W.; Woelk, K. [and others

    1995-12-01

    Toroid detectors have distinct NMR sensitivity and imaging advantages. The magnetic field lines are nearly completely contained within the active volume element of a toroid. This results in high NMR signal sensitivity. In addition, the toroid detector may be placed next to the metallic walls of a containment vessel with minimal signal loss due to magnetic coupling with the metal container. Thus, the toroid detector is ideal for static high pressure or continuous flow monitoring systems. Toroid NMR detectors have been used to follow the hydroformylation of olefins in supercritical fluids under industrial process conditions. Supercritical fluids are potentially ideal media for conducting catalytic reactions that involve gaseous reactants, including H{sub 2}, CO, and CO{sub 2}. The presence of a single homogeneous reaction phase eliminates the gas-liquid mixing problem of alternative two-phase systems, which can limit process rates and adversely affect hydroformylation product selectivities. A second advantage of toroid NMR detectors is that they exhibit a well-defined gradient in the rf field. This magnetic field gradient can be used for NMR imaging applications. Distance resolutions of 20 {mu} have been obtained.

  10. Applications of toroids in high-pressure NMR spectroscopy

    SciTech Connect

    Klingler, R.J.; Rathke, J.W.; Woelk, K.; Kramarz, K.W.; Gerald, R. [Argonne National Lab., IL (United States)

    1995-12-31

    Toroid detectors have distinct NMR sensitivity and imaging advantages. The magnetic field lines are nearly completely contained within the active volume element of a toroid. This results in high NMR signal sensitivity. In addition, the toroid detector may be placed next to the metallic walls of a containment vessel with minimal signal loss due to magnetic coupling with the metal container. Thus, the toroid detector is ideal for static high pressure or continuous flow monitoring systems. Toroid NMR detectors have been used to follow the hydroformylation of olefins in supercritical fluids under industrial process conditions. Supercritical fluids are potentially ideal media for conducting catalytic reactions that involve gaseous reactants, including H{sub 2}, CO, and CO{sub 2}. The presence of a single homogeneous reaction phase eliminates the gas-liquid mixing problem of alternative two-phase systems, which can limit process rates and adversely affect hydroformylation product selectivities. A second advantage of toroid NMR detectors is that they exhibit a well-defined gradient in the rf field. This magnetic field gradient can be used for NMR imaging applications. Distance resolutions of 20 {mu} have been obtained.

  11. Characterization of amorphous material in shocked quartz by NMR spectroscopy

    SciTech Connect

    Assink, R.A.; Boslough, M.B.; Cygan, R.T.

    1993-08-01

    Nuclear magnetic resonance (NMR) analysis of the recovered products from a series of controlled explosive shock-loading experiments on quartz powders was performed to investigate shock-induced amorphization processes. Silicon-29 NMR spectroscopy is an excellent probe of the local bonding environment of silicon in minerals and is capable of detecting and characterizing amorphous and disordered components. NMR spectra obtained for the recovered material exhibit a narrow resonance associated with the shocked crystalline material, and a broad component consistent with an amorphous phase despite the absence of evidence for glass from optical microscopy. The NMR measurements were performed over a range of recycle times from 1 to 3 {times} 10{sup 5} S. Results demonstrate that the magnetization in both the crystalline and amorphous material following power-law behavior as a function of recycle time. The amorphous component dominates the spectra for short NMR recycle times due to its shorter relaxation time relative to the crystalline material. Fractal analysis of the power-law relations suggests a fractal dimension of 2 for the amorphous phase and 3 for the crystalline phase.

  12. NMR measurements on obliquely evaporated Co-Cr films

    NASA Astrophysics Data System (ADS)

    Lodder, J. C.; van Kranenburg, H.; Takei, K.; Maeda, Y.

    1993-01-01

    The distribution of the hyperfine fields or the resonance frequencies in metals and alloys obtained by NMR measurements have been known for a long time. Recently, new experimental data have been published about thin films for studying their chemical inhomogeneities. An example is the study on sputtered and evaporated Co-Cr layers. In this paper we report on the compositional distribution of co-evaporated Co-Cr films by using the Co spin-echo NMR technique. For comparison single source evaporated samples of Co-Cr and pure Co as well as two alloyed ribbons ("bulk" samples) have also been measured. Based on the NMR results the local Cr concentration of the ferromagnetic and less ferromagnetic regions are determined. In comparison the data from the co-evaporated films, even at low substrate temperature, have clearly shown the presence of a process-induced compositional separation. This is in qualitative agreement with the magnetic properties of the samples.

  13. A versatile magnetic field gradient control system for NMR imaging

    NASA Astrophysics Data System (ADS)

    Bottomley, P. A.

    1981-09-01

    A complete digitally controlled magnetic field gradient system for NMR imaging is described; the device is capable of operating in the projection reconstruction (PR), the sensitive line (SL), and the sensitive point (SP) modes. Gradient scanning is achieved via clocked eight-bit counters which step either a digital vector generator when operating in the PR mode, or a series of MDACs when in the SL or SP modes. Versatile control of the image array size, the spatial resolution, the orientation of projections, and the positioning of sensitive lines and points is provided without the use of moving parts or microprocessors and with little or no computer interfacing. The device will function either independent of a conventional NMR Fourier transform spectrometer system when manual gradient scanning is employed, or synchronously with the spectrometer when gradients are scanned automatically. A gradient coil design and criteria for establishing the gradient amplitudes are discussed, and some NMR images which were generated with the system are presented.

  14. Applications of saturation transfer difference NMR in biological systems.

    PubMed

    Bhunia, Anirban; Bhattacharjya, Surajit; Chatterjee, Subhrangsu

    2012-05-01

    The method of saturation transfer difference (STD) nuclear magnetic resonance (NMR) is an indispensable NMR tool in drug discovery. It identifies binding epitope(s) at the atomic resolution of small molecule ligands (e.g. organic drugs, peptides and oligosaccharides), while interacting with their receptors, such as proteins and/or nucleic acids. The method is widely used to screen active drug molecules, simultaneously ranking them in a qualitative way. STD NMR is highly successful for a variety of high molecular weight systems, such as whole viruses, platelets, intact cells, lipopolysaccharide micelles, membrane proteins, recombinant proteins and dispersion pigments. Modifications of STD pulse programs using (13)C and (15)N nuclei are now used to overcome the signal overlapping that occurs with more complex structures. PMID:22210119

  15. A new unfree fluid index in sandstones through NMR studies

    SciTech Connect

    Borgia, G.C. [Univ. of Bologna (Italy)

    1996-06-01

    Nuclear magnetic resonance (NMR) of {sup 1}H nuclei of liquids in saturated porous rocks furnishes an increasingly important tool in core analysis as well as in well-logging. In particular, there are several basic questions regarding NMR downhole logging in reservoir sandstones. For this reason, it is of interest to investigate the laboratory NMR properties to identify some important basic mechanisms. This paper presents new correlations among porosity, {phi}, irreducible water saturation, S{sub wi}, formation resistivity factor, F, and the geometric mean longitudinal relaxation time, T{sub 1}g. Equilibrium magnetization and longitudinal relaxation, T{sub 1}, measurements were performed on 57 clean sandstone samples from 12 oil and gas reservoirs.

  16. Fer expansion for effective propagators and Hamiltonians in NMR

    NASA Astrophysics Data System (ADS)

    Madhu, P. K.; Kurur, Narayanan D.

    2006-01-01

    Solving a time-dependent linear differential equation towards obtaining propagators is a central problem to NMR in general and solid-state NMR in particular. Designing of various pulse sequences and understanding of different experiments are based on the form of effective Hamiltonians and/or effective propagators. The commonly used methods for this are average Hamiltonian theory based on Magnus expansion and Floquet theory where use of van Vleck perturbation is employed. Here, we dwell upon an alternative expansion method to solving time-dependent linear differential equations called Fer expansion. We highlight the basics of this scheme and hint at its potential by considering Bloch-Siegert shift and heteronuclear dipolar decoupling in solid-state NMR.

  17. Relaxivities of different superparamagnetic particles for application in NMR tomography

    NASA Astrophysics Data System (ADS)

    Coroiu, I.

    1999-07-01

    The development of nuclear magnetic resonance (NMR) imaging technique as a clinical diagnostic modality has prompted the need for a new class of pharmaceuticals, so-called magneto-pharmaceuticals. These drugs must be administered to a patient in order to (1) enhance the image contrast between normal and diseased tissue and/or (2) indicate the status of organ functions or blood flow. A number of different agents have been suggested as potential NMR contrast agents, most of which is highly paramagnetic. Superparamagnetic particles represent an alternative class of NMR contrast agents that usually referred to as T2 or T ?2 contrast agents, opposed to T1 agents such as paramagnetic chelates. Because of their large permanent dipole moments these agents are able to relax neighbouring nuclei faster than paramagnetic ions. The synthesis and measurements of the transverse R2 and longitudinal R1 relaxivities of some ferro-, ferri- and superparamagnetic particles' suspensions are presented.

  18. Characterizing protein-glycosaminoglycan interactions using solution NMR spectroscopy.

    PubMed

    Joseph, Prem Raj B; Poluri, Krishna Mohan; Sepuru, Krishna Mohan; Rajarathnam, Krishna

    2015-01-01

    Solution nuclear magnetic resonance (NMR) spectroscopy and, in particular, chemical shift perturbation (CSP) titration experiments are ideally suited for characterizing the binding interface of macromolecular complexes. (1)H-(15)?N-HSQC-based CSP studies have become the method of choice due to their simplicity, short time requirements, and not requiring high-level NMR expertise. Nevertheless, CSP studies for characterizing protein-glycosaminoglycan (GAG) interactions have been challenging due to binding-induced aggregation/precipitation and/or poor quality data. In this chapter, we discuss how optimizing experimental variables such as protein concentration, GAG size, and sensitivity of NMR instrumentation can overcome these roadblocks to obtain meaningful structural insights into protein-GAG interactions. PMID:25325963

  19. Advances in solid-state NMR of cellulose.

    PubMed

    Foston, Marcus

    2014-06-01

    Nuclear magnetic resonance (NMR) spectroscopy is a well-established analytical and enabling technology in biofuel research. Over the past few decades, lignocellulosic biomass and its conversion to supplement or displace non-renewable feedstocks has attracted increasing interest. The application of solid-state NMR spectroscopy has long been seen as an important tool in the study of cellulose and lignocellulose structure, biosynthesis, and deconstruction, especially considering the limited number of effective solvent systems and the significance of plant cell wall three-dimensional microstructure and component interaction to conversion yield and rate profiles. This article reviews common and recent applications of solid-state NMR spectroscopy methods that provide insight into the structural and dynamic processes of cellulose that control bulk properties and biofuel conversion. PMID:24590189

  20. Canopy Dynamics in Nanoscale Ionic Materials Probed by NMR

    NASA Astrophysics Data System (ADS)

    Mirau, Peter

    2013-03-01

    Nanoscale ionic materials (NIMs) are hybrids prepared from ionically functionalized nanoparticles (NP) neutralized by oligomeric polymer counter-ions. NIMs are designed to behave as liquids under ambient conditions in the absence of solvent and have no volatile organic content, making them useful for a number of applications. We have used NMR relaxation and pulse-field gradient NMR to probe local and collective canopy dynamics in NIMs based on silica nanoparticles (NP), fullerols and proteins in order to understand the relationship between the core and canopy structure and the bulk properties. The NMR studies show that the canopy dynamics depend on the degree of neutralization, the canopy radius of gyration and molecular crowding at the ionically modified NP surface. The viscosity in NIMs can be directly controlled with the addition of ions that enhance the exchange rate for polymers at the NP surface. These results show that NIMs for many applications can be prepared by controlling the dynamics of the NP interface.

  1. A Theory of Protein Dynamics to Predict NMR Relaxation

    PubMed Central

    Caballero-Manrique, Esther; Bray, Jenelle K.; Deutschman, William A.; Dahlquist, Frederick W.; Guenza, Marina G.

    2007-01-01

    We present a theoretical, site-specific, approach to predict protein subunit correlation times, as measured by NMR experiments of 1H-15N nuclear Overhauser effect, spin-lattice relaxation, and spin-spin relaxation. Molecular dynamics simulations are input to our equation of motion for protein dynamics, which is solved analytically to produce the eigenvalues and the eigenvectors that specify the NMR parameters. We directly compare our theoretical predictions to experiments and to simulation data for the signal transduction chemotaxis protein Y (CheY), which regulates the swimming response of motile bacteria. Our theoretical results are in good agreement with both simulations and experiments, without recourse to adjustable parameters. The theory is general, since it allows calculations of any dynamical property of interest. As an example, we present theoretical calculations of NMR order parameters and x-ray Debye-Waller temperature factors; both quantities show good agreement with experimental data. PMID:17766356

  2. Detection of free chloride in concrete by NMR

    SciTech Connect

    Yun Haebum; Patton, Mark E.; Garrett, James H.; Fedder, Gary K.; Frederick, Kevin M.; Hsu, J.-J.; Lowe, Irving J.; Oppenheim, Irving J.; Sides, Paul J

    2004-03-01

    Laboratory experiments to detect chloride in a cement matrix using pulse nuclear magnetic resonance (NMR) were conducted. The coils were in the centimeter scale and the magnetic field was 2.35 T. NMR signals were obtained from both aqueous chloride solution and samples of both regular and white Portland cement (WPC). A concrete sample from a sidewalk that had been in the field for 20 years was also tested. The experiments demonstrated that the signal-to-noise ratio (SNR) for a centimeter-scale cement sample volume is so small, even after averaging, that sample volumes much lower than that are unlikely to produce measurable signals at fields of 1 T or below. The consequence is that the potential for realizing an embedded NMR-based sensor including the magnet is low. Parametric studies identify feasible alternative coil diameters and magnetic field strengths for detecting chloride ion concentrations in hardened concrete.

  3. Toroid cavity/coil NMR multi-detector

    DOEpatents

    Gerald, II, Rex E. (Brookfield, IL); Meadows, Alexander D. (Indianapolis, IN); Gregar, Joseph S. (Naperville, IL); Rathke, Jerome W. (Homer Glen, IL)

    2007-09-18

    An analytical device for rapid, non-invasive nuclear magnetic resonance (NMR) spectroscopy of multiple samples using a single spectrometer is provided. A modified toroid cavity/coil detector (TCD), and methods for conducting the simultaneous acquisition of NMR data for multiple samples including a protocol for testing NMR multi-detectors are provided. One embodiment includes a plurality of LC resonant circuits including spatially separated toroid coil inductors, each toroid coil inductor enveloping its corresponding sample volume, and tuned to resonate at a predefined frequency using a variable capacitor. The toroid coil is formed into a loop, where both ends of the toroid coil are brought into coincidence. Another embodiment includes multiple micro Helmholtz coils arranged on a circular perimeter concentric with a central conductor of the toroid cavity.

  4. Intrauterine fetal brain NMR spectroscopy: 1H and 31P studies in rats

    SciTech Connect

    Nakada, T.; Kwee, I.L.; Suzuki, N.; Houkin, K. (Veterans Administration Medical Center, Martinez, CA (USA))

    1989-11-01

    Fetal brain metabolism was investigated in utero noninvasively using multinuclear nuclear magnetic resonance spectroscopy in rats at two representative prenatal stages: early (17-18 days) and late (20-21 days) stages. Phosphorus-31 (31P) spectroscopy revealed that phosphocreatine is significantly lower in the early stage and increases to the level of early neonates by the late prenatal stage. Intracellular pH at the early stage was found to be strikingly high (7.52 +/- 0.21) and decreased to a level similar to that of neonates by the late stage (7.29 +/- 0.07). Phosphomonoester levels at both stages were similar to the values reported for early neonates. Water-suppressed proton (1H) spectroscopy demonstrated a distinctive in vivo fetal brain spectral pattern characterized by low levels of N-acetyl aspartate and high levels of taurine. High-resolution proton spectroscopy and homonuclear chemical-shift correlate spectroscopy of brain perchloric acid extracts confirmed these in vivo findings. In vitro 31P spectroscopy of acidified chloroform methanol extracts showed the characteristic membrane phospholipid profiles of fetal brain. The phosphatidylethanolamine (PE)-to-phosphatidylcholine (PC) ratio (PE/PC) did not show significant changes between the two stages at 0.40 +/- 0.11, a value similar to that of early neonates.

  5. An analytical methodology for magnetic field control in unilateral NMR

    NASA Astrophysics Data System (ADS)

    Marble, Andrew E.; Mastikhin, Igor V.; Colpitts, Bruce G.; Balcom, Bruce J.

    2005-05-01

    Traditionally, unilateral NMR systems such as the NMR-MOUSE have used the fringe field between two bar magnets joined with a yoke in a 'U' geometry. This allows NMR signals to be acquired from a sensitive volume displaced from the magnets, permitting large samples to be investigated. The drawback of this approach is that the static field ( B0) generated in this configuration is inhomogeneous, and has a large, nonlinear, gradient. As a consequence, the sensitive volume of the instrument is both small and ill defined. Empirical redesign of the permanent magnet array producing the B0 field has yielded instruments with magnetic field topologies acceptable for varying applications. The drawback of current approaches is the lack of formalism in the control of B0. Rather than tailoring the magnet geometry to NMR investigations, measurements must be tailored to the available magnet geometry. In this work, we present a design procedure whereby the size, shape, field strength, homogeneity, and gradients in the sensitive spot of a unilateral NMR sensor can be controlled. Our design uses high permeability pole pieces, shaped according to the contours of an analytical expression, to control B0, allowing unilateral NMR instruments to be designed to generate a controlled static field topology. We discuss the approach in the context of previously published design techniques, and explain the advantages inherent in our strategy as compared to other optimization methods. We detail the design, simulation, and construction of a unilateral magnet array using our approach. It is shown that the fabricated array exhibits a B0 topology consistent with the design. The utility of the design is demonstrated in a sample nondestructive testing application. Our design methodology is general, and defines a class of unilateral permanent magnet arrays in which the strength and shape of B0 within the sensitive volume can be controlled.

  6. An analytical methodology for magnetic field control in unilateral NMR.

    PubMed

    Marble, Andrew E; Mastikhin, Igor V; Colpitts, Bruce G; Balcom, Bruce J

    2005-05-01

    Traditionally, unilateral NMR systems such as the NMR-MOUSE have used the fringe field between two bar magnets joined with a yoke in a 'U' geometry. This allows NMR signals to be acquired from a sensitive volume displaced from the magnets, permitting large samples to be investigated. The drawback of this approach is that the static field (B0) generated in this configuration is inhomogeneous, and has a large, nonlinear, gradient. As a consequence, the sensitive volume of the instrument is both small and ill defined. Empirical redesign of the permanent magnet array producing the B0 field has yielded instruments with magnetic field topologies acceptable for varying applications. The drawback of current approaches is the lack of formalism in the control of B0. Rather than tailoring the magnet geometry to NMR investigations, measurements must be tailored to the available magnet geometry. In this work, we present a design procedure whereby the size, shape, field strength, homogeneity, and gradients in the sensitive spot of a unilateral NMR sensor can be controlled. Our design uses high permeability pole pieces, shaped according to the contours of an analytical expression, to control B0, allowing unilateral NMR instruments to be designed to generate a controlled static field topology. We discuss the approach in the context of previously published design techniques, and explain the advantages inherent in our strategy as compared to other optimization methods. We detail the design, simulation, and construction of a unilateral magnet array using our approach. It is shown that the fabricated array exhibits a B0 topology consistent with the design. The utility of the design is demonstrated in a sample nondestructive testing application. Our design methodology is general, and defines a class of unilateral permanent magnet arrays in which the strength and shape of B0 within the sensitive volume can be controlled. PMID:15809175

  7. Quantitating Metabolites in Protein Precipitated Serum Using NMR Spectroscopy

    PubMed Central

    2015-01-01

    Quantitative NMR-based metabolite profiling is challenged by the deleterious effects of abundant proteins in the intact blood plasma/serum, which underscores the need for alternative approaches. Protein removal by ultrafiltration using low molecular weight cutoff filters thus represents an important step. However, protein precipitation, an alternative and simple approach for protein removal, lacks detailed quantitative assessment for use in NMR based metabolomics. In this study, we have comprehensively evaluated the performance of protein precipitation using methanol, acetonitrile, perchloric acid, and trichloroacetic acid and ultrafiltration approaches using 1D and 2D NMR, based on the identification and absolute quantitation of 44 human blood metabolites, including a few identified for the first time in the NMR spectra of human serum. We also investigated the use of a “smart isotope tag,” 15N-cholamine for further resolution enhancement, which resulted in the detection of a number of additional metabolites. 1H NMR of both protein precipitated and ultrafiltered serum detected all 44 metabolites with comparable reproducibility (average CV, 3.7% for precipitation; 3.6% for filtration). However, nearly half of the quantified metabolites in ultrafiltered serum exhibited 10–74% lower concentrations; specifically, tryptophan, benzoate, and 2-oxoisocaproate showed much lower concentrations compared to protein precipitated serum. These results indicate that protein precipitation using methanol offers a reliable approach for routine NMR-based metabolomics of human blood serum/plasma and should be considered as an alternative to ultrafiltration. Importantly, protein precipitation, which is commonly used by mass spectrometry (MS), promises avenues for direct comparison and correlation of metabolite data obtained from the two analytical platforms to exploit their combined strength in the metabolomics of blood. PMID:24796490

  8. Brute-Force Hyperpolarization for NMR and MRI.

    PubMed

    Hirsch, Matthew L; Kalechofsky, Neal; Belzer, Avrum; Rosay, Melanie; Kempf, James G

    2015-07-01

    Hyperpolarization (HP) of nuclear spins is critical for ultrasensitive nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI). We demonstrate an approach for >1500-fold enhancement of key small-molecule metabolites: 1-(13)C-pyruvic acid, 1-(13)C-sodium lactate, and 1-(13)C-acetic acid. The (13)C solution NMR signal of pyruvic acid was enhanced 1600-fold at B = 1 T and 40 °C by pre-polarizing at 14 T and ?2.3 K. This "brute-force" approach uses only field and temperature to generate HP. The noted 1 T observation field is appropriate for benchtop NMR and near the typical 1.5 T of MRI, whereas high-field observation scales enhancement as 1/B. Our brute-force process ejects the frozen, solid sample from the low-T, high-B polarizer, passing it through low field (B < 100 G) to facilitate "thermal mixing". That equilibrates (1)H and (13)C in hundreds of milliseconds, providing (13)C HP from (1)H Boltzmann polarization attained at high B/T. The ejected sample arrives at a room-temperature, permanent magnet array, where rapid dissolution with 40 °C water yields HP solute. Transfer to a 1 T NMR system yields (13)C signals with enhancements at 80% of ideal for noted polarizing conditions. High-resolution NMR of the same product at 9.4 T had consistent enhancement plus resolution of (13)C shifts and J-couplings for pyruvic acid and its hydrate. Comparable HP was achieved with frozen aqueous lactate, plus notable enhancement of acetic acid, demonstrating broader applicability for small-molecule NMR and metabolic MRI. Brute-force avoids co-solvated free-radicals and microwaves that are essential to competing methods. Here, unadulterated samples obviate concerns about downstream purity and also exhibit slow solid-state spin relaxation, favorable for transporting HP samples. PMID:26098752

  9. Dynamic nuclear polarization in biomolecular solid state NMR : methods and applications in peptides and membrane proteins

    E-print Network

    Bajaj, Vikram Singh

    2007-01-01

    Solid state NMR can probe structure and dynamics on length scales from the atomic to the supramolecular. However, low sensitivity limits its application in macromolecules. NMR sensitivity can be improved by dynamic nuclear ...

  10. Electrical noise model for detection circuitry of an NMR-based formation evaluation Tool

    E-print Network

    Maison, Julie Laure K

    2011-01-01

    The RF signals received from Nuclear Magnetic Resonance (NMR) measurements in logging while drilling NMR instruments are often of the same amplitude as the noise generated by the instruments. Designers of these devices are ...

  11. Optimization of THz Wave Coupling into Samples in DNP/NMR Spectroscopy

    E-print Network

    Barnes, Alexander

    High power millimeter wave and terahertz sources are used in DNP/NMR spectroscopy to greatly enhance the NMR signal. A key issue is the efficient coupling of the source power to the sample. We present HFSS calculations ...

  12. Gerhard Wider: Structure Determination of Biological Macromolecules using NMR. Structure Determination of Biological

    E-print Network

    Wider, Gerhard

    Gerhard Wider: Structure Determination of Biological Macromolecules using NMR. -1- Structure Determination of Biological Macromolecules in Solution Using NMR spectroscopy Gerhard Wider Institut fürTechniques 29, 1278­1294 (2000) #12;Gerhard Wider: Structure Determination of Biological Macromolecules using

  13. COMPREHENSIVE PROGRESS REPORT FOR FOURIER TRANSFORM NMR (NUCLEAR MAGNETIC RESONANCE) OF METALS OF ENVIRONMENTAL SIGNIFICANCE

    EPA Science Inventory

    Interactions of the metals cadmium and selenium with various biologically important substrates were studied by nuclear magnetic resonance (NMR) spectroscopy. Cadmium-113 NMR was used for a critical examination of three metalloproteins: concanavalin A, bovine superoxide dismutase ...

  14. The refocused INADEQUATE MAS NMR experiment in multiple spin-systems: Interpreting observed correlation

    E-print Network

    Baltisberger, Jay H.

    The refocused INADEQUATE MAS NMR experiment in multiple spin-systems: Interpreting observed The robustness of the refocused INADEQUATE MAS NMR pulse sequence for probing through-bond connectivities has

  15. Experimental quantum deletion in an NMR quantum information processor

    NASA Astrophysics Data System (ADS)

    Long, Yu; Feng, GuanRu; Pearson, Jasong; Long, GuiLu

    2014-07-01

    We report an NMR experimental realization of a rapid quantum deletion algorithm that deletes marked states in an unsorted database. Unlike classical deletion, where search and deletion are equivalent, quantum deletion can be implemented with only a single query, which achieves exponential speed-up compared to the optimal classical analog. In the experimental realization, the GRAPE algorithm was used to obtain an optimized NMR pulse sequence, and the efficient method of maximum-likelihood has been used to reconstruct the experimental output state.

  16. Complete NMR characterization of lychnose from Stellaria media (L.) Vill.

    PubMed

    Vanhaecke, Mieke; Van den Ende, Wim; Van Laere, André; Herdewijn, Piet; Lescrinier, Eveline

    2006-11-27

    Lychnose (alpha-D-Gal-(1-->6)-alpha-D-Glc-(1-->2)-beta-D-Fru-(1-->1)-alpha-D-Gal) was isolated from Stellaria media, a representative member of the Caryophyllaceae plant family. Weak acid hydrolysis, enzymatic hydrolysis and complete NMR characterization were performed to confirm the identity of the tetrasaccharide. All (1)H and (13)C resonances were unambiguously assigned and the conformation of the sugars was determined using one and two dimensional NMR techniques. Anomeric characterizations in lychnose were confirmed from HMBC and NOESY spectra. PMID:16997290

  17. The HRMAS-NMR tool in foodstuff characterisation.

    PubMed

    Valentini, Massimiliano; Ritota, Mena; Cafiero, Caterina; Cozzolino, Sara; Leita, Liviana; Sequi, Paolo

    2011-12-01

    High resolution magic angle spinning, that is, HRMAS, is a quite novel tool in NMR spectroscopy; it offers the almost unique opportunity of measuring intact tissues disguised as suspended or swollen in a deuterated solvent. The feasibility of (1)H-HRMAS-NMR in foodstuff characterisation has been exploited, but in spite of this, its applications are still limited. Metabolic profiling and biopolymer composition and aggregation are the topics investigated until now for raw vegetables, meat and processed foodstuff. Almost all known studies are reported in the next pages. PMID:22290702

  18. A comment on powder averaging in wide line NMR.

    PubMed

    Iwaniec, T; Kopiecki, R; Szymanski, S

    2015-01-01

    Computer calculations of wide line NMR spectra of powders usually involve numerical evaluation of double integrals over two Euler angles. Practice confirms intuition-based expectations that the integration results should be independent from the choice of the crystal-fixed (or molecule-fixed) coordinate system used in the calculations. However, a closer inspection of the relevant integration formulas may make one wonder why this is so. The present paper provides a rigorous mathematical proof of the validity of these intuitive predictions, by formulating the problem in terms of surface integrals on a sphere, which has presumably no precedence in the NMR literature. PMID:25912210

  19. NMR STUDY OF MOLECULAR REFORIENTATION UNDER FIVEFOLD SYMMETRY SOLID PERMETHYLFERROCENE

    SciTech Connect

    Wemmer, D.E.; Ruben, D.J.; Pines, A.

    1980-08-01

    The ring reorientation in permethylferrocene has been studied using high resolution solid state {sup 13}C NMR. The constraints which symmetry places upon the number and types of motional parameters which may be determined from the NMR spectrum are discussed. From comparison of the experimental lineshapes in the slow reorientation temperatures range with theoretical models for random rotations and symmetry related jumps, it is concluded that the reorientation occurs as jumps between symmetry related orientations with jumps of 2{pi}/5 highly favored over 4{pi}/5. The activation energy derived for the jump process is 13.5 kjoules/mole.

  20. MVAPACK: A Complete Data Handling Package for NMR Metabolomics

    PubMed Central

    2015-01-01

    Data handling in the field of NMR metabolomics has historically been reliant on either in-house mathematical routines or long chains of expensive commercial software. Thus, while the relatively simple biochemical protocols of metabolomics maintain a low barrier to entry, new practitioners of metabolomics experiments are forced to either purchase expensive software packages or craft their own data handling solutions from scratch. This inevitably complicates the standardization and communication of data handling protocols in the field. We report a newly developed open-source platform for complete NMR metabolomics data handling, MVAPACK, and describe its application on an example metabolic fingerprinting data set. PMID:24576144

  1. NMR-Based Encoding and Processing of Alphanumeric Information

    NASA Astrophysics Data System (ADS)

    Ratner, Tamar; Reany, Ofer; Keinan, Ehud

    We present here a novel experimental computing device that is based on 1H Nuclear Magnetic Resonance (NMR) readout of chemical information. This chemical encoding system utilizes two measurable parameters of homogeneous mixtures, chemical shift and peak integration, for different applications: 1) text encoding device that is based on spectral representation of a sequence of symbols, 2) encoding of 21-digit binary numbers, each represented by an NMR spectrum, and their algebraic manipulations, such as addition and subtraction, and 3) encoding of 21-digit decimal numbers.

  2. Nonuniform sampling and maximum entropy reconstruction in multidimensional NMR.

    PubMed

    Hoch, Jeffrey C; Maciejewski, Mark W; Mobli, Mehdi; Schuyler, Adam D; Stern, Alan S

    2014-02-18

    NMR spectroscopy is one of the most powerful and versatile analytic tools available to chemists. The discrete Fourier transform (DFT) played a seminal role in the development of modern NMR, including the multidimensional methods that are essential for characterizing complex biomolecules. However, it suffers from well-known limitations: chiefly the difficulty in obtaining high-resolution spectral estimates from short data records. Because the time required to perform an experiment is proportional to the number of data samples, this problem imposes a sampling burden for multidimensional NMR experiments. At high magnetic field, where spectral dispersion is greatest, the problem becomes particularly acute. Consequently multidimensional NMR experiments that rely on the DFT must either sacrifice resolution in order to be completed in reasonable time or use inordinate amounts of time to achieve the potential resolution afforded by high-field magnets. Maximum entropy (MaxEnt) reconstruction is a non-Fourier method of spectrum analysis that can provide high-resolution spectral estimates from short data records. It can also be used with nonuniformly sampled data sets. Since resolution is substantially determined by the largest evolution time sampled, nonuniform sampling enables high resolution while avoiding the need to uniformly sample at large numbers of evolution times. The Nyquist sampling theorem does not apply to nonuniformly sampled data, and artifacts that occur with the use of nonuniform sampling can be viewed as frequency-aliased signals. Strategies for suppressing nonuniform sampling artifacts include the careful design of the sampling scheme and special methods for computing the spectrum. Researchers now routinely report that they can complete an N-dimensional NMR experiment 3(N-1) times faster (a 3D experiment in one ninth of the time). As a result, high-resolution three- and four-dimensional experiments that were prohibitively time consuming are now practical. Conversely, tailored sampling in the indirect dimensions has led to improved sensitivity. Further advances in nonuniform sampling strategies could enable further reductions in sampling requirements for high resolution NMR spectra, and the combination of these strategies with robust non-Fourier methods of spectrum analysis (such as MaxEnt) represent a profound change in the way researchers conduct multidimensional experiments. The potential benefits will enable more advanced applications of multidimensional NMR spectroscopy to study biological macromolecules, metabolomics, natural products, dynamic systems, and other areas where resolution, sensitivity, or experiment time are limiting. Just as the development of multidimensional NMR methods presaged multidimensional methods in other areas of spectroscopy, we anticipate that nonuniform sampling approaches will find applications in other forms of spectroscopy. PMID:24400700

  3. Comment on "NMR Experiment Factors Numbers with Gauss Sums"

    E-print Network

    J. A. Jones

    2007-04-16

    Mehring et al. have recently described an elegant nuclear magnetic resonance (NMR) experiment implementing an algorithm to factor numbers based on the properties of Gauss sums. Similar experiments have also been described by Mahesh et al. In fact these algorithms do not factor numbers directly, but rather check whether a trial integer $\\ell$ is a factor of a given integer $N$. Here I show that these NMR schemes cannot be used for factor checking without first implicitly determining whether or not $\\ell$ is a factor of $N$.

  4. Anti-flammable properties of capable phosphorus-nitrogen containing triazine derivatives on cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Most of new phosphorus-nitrogen containing compounds were prepared by organic reactions of cyanuric chloride and phosphonates. They were characterized by analytical tools such as proton (1H), carbon (13C), and phosphorus (31P) nuclear magnetic resonance (NMR) spectroscopy and elemental analysis (EA)...

  5. Study on crystallographically inequivalent protons in RbH2AsO4 using static NMR and MAS NMR

    NASA Astrophysics Data System (ADS)

    Lim, Ae Ran; Lee, Kwang-Sei

    2015-02-01

    Two inequivalent protons from 1H NMR spectra of RbH2AsO4 in the paraelectric phase were distinguished using static NMR and MAS NMR. From the 1H spin-lattice relaxation times in the laboratory frame, T1, and rotating frame, T1?, of the two crystallographically inequivalent hydrogen sites, i.e., H(1) and H(2), the temperature dependences of T1 and T1? for H(1) were related to the reorientational motion. The shorter H(1) bonds give rise to stronger H-bonds, and protons involved in stronger H-bonds have long relaxation times. Consequently, the RbH2AsO4 structure has two crystallographically inequivalent sites with two different hydrogen-bond lengths.

  6. 3D-printed system optimizing dissolution of hyperpolarized gaseous species for micro-sized NMR.

    PubMed

    Causier, A; Carret, G; Boutin, C; Berthelot, T; Berthault, P

    2015-04-21

    Dissolution of hyperpolarized species in liquids of interest for NMR is often hampered by the presence of bubbles that degrade the field homogeneity. Here a device composed of a bubble pump and a miniaturized NMR cell both fitted inside the narrow bore of an NMR magnet is built by 3D printing. (129)Xe NMR experiments performed with hyperpolarized xenon reveal high and homogeneous dissolution of the gas in water. PMID:25805248

  7. LC-NMR Technique in the Analysis of Phytosterols in Natural Extracts.

    PubMed

    Horník, St?pán; Sajfrtová, Marie; Karban, Jind?ich; Sýkora, Jan; B?ezinová, Anna; Wimmer, Zden?k

    2013-01-01

    The ability of LC-NMR to detect simultaneously free and conjugated phytosterols in natural extracts was tested. The advantages and disadvantages of a gradient HPLC-NMR method were compared to the fast composition screening using SEC-NMR method. Fractions of free and conjugated phytosterols were isolated and analyzed by isocratic HPLC-NMR methods. The results of qualitative and quantitative analyses were in a good agreement with the literature data. PMID:24455424

  8. NMR studies of laser-polarized xenon gas flow in porous and granular media

    Microsoft Academic Search

    R. W. Mair; M. S. Rosen; R. L. Walsworth; R. Wang; D. G. Cory; D. Candela

    2003-01-01

    NMR techniques that are commonly used to measure diffusion can also be used to measure fluid velocity and\\/or acceleration. In recent years, laser-polarized noble gas NMR has developed into a powerful tool for spin density and diffusion imaging; however few attempts have been made to study gas flow by NMR. We report initial NMR velocity measurements of continuously flowing laser-polarized

  9. LC-NMR Technique in the Analysis of Phytosterols in Natural Extracts

    PubMed Central

    Horník, Št?pán; Sajfrtová, Marie; Sýkora, Jan; B?ezinová, Anna; Wimmer, Zden?k

    2013-01-01

    The ability of LC-NMR to detect simultaneously free and conjugated phytosterols in natural extracts was tested. The advantages and disadvantages of a gradient HPLC-NMR method were compared to the fast composition screening using SEC-NMR method. Fractions of free and conjugated phytosterols were isolated and analyzed by isocratic HPLC-NMR methods. The results of qualitative and quantitative analyses were in a good agreement with the literature data. PMID:24455424

  10. Ultrafast 2D NMR Spectroscopy Using Sinusoidal Gradients: Principles and Ex Vivo Brain Investigations

    E-print Network

    Frydman, Lucio

    Ultrafast 2D NMR Spectroscopy Using Sinusoidal Gradients: Principles and Ex Vivo Brain ultrafast acquisitions of 2D NMR spectra with suitable spectral widths on a microimaging probe (for both Wiley-Liss, Inc. Key words: ultrafast 2D NMR; magnetic resonance spectros- copy; brain metabolites; 2D

  11. The Effect of Ergosterol on Dipalmitoylphosphatidylcholine Bilayers: A Deuterium NMR and Calorimetric Study

    Microsoft Academic Search

    Ya-Wei Hsueh; Kyle Gilbert; C. Trandum; M. Zuckermann; Jenifer Thewalt

    2005-01-01

    We have studied the effect of ergosterol, an important component of fungal plasma membranes, on the physical properties of dipalmitoylphosphatidylcholine (DPPC) multibilayers using deuterium nuclear magnetic resonance (2H NMR) and differential scanning calorimetry (DSC). For the 2H NMR experiments the sn-1 chain of DPPC was perdeuterated and NMR spectra were taken as a function of temperature and ergosterol concentration. The

  12. Unique opportunities for NMR methods in structural genomics Gaetano T. Montelione Cheryl Arrowsmith

    E-print Network

    Powers, Robert

    Unique opportunities for NMR methods in structural genomics Gaetano T. Montelione Æ Cheryl of structural genomics Á Functional genomics Á NMR Á Crystallography Á NMR methods Á Protein Structure contribu- tions of structural genomics (SG) for biomedical research, we envision many future opportunities

  13. ELECTROMAGNETIC PHANTOM DESIGN FOR MEASUREMENT AND IMAGING QUALITY TESTING USING NMR IMAGING METHODS

    Microsoft Academic Search

    I. Frollo; P. Andris; Z. Holúbeková

    2009-01-01

    Electromagnetic phantom design for measurement and imaging quality testing using NMR imaging has been performed. First attempts of electromagnetic phantom computation and testing on an experimental NMR 0,1 T imager were accomplished. The existing geometrical and chemical phantoms are generally used for testing of NMR imaging systems. They are simple cylindrical or rectangular objects with different dimensions and shapes with

  14. Automatic Alignment of High-Resolution NMR Spectra Using a Bayesian Estimation Approach

    E-print Network

    Wang, Zhou

    Automatic Alignment of High-Resolution NMR Spectra Using a Bayesian Estimation Approach Zhou Wang Conference on Pattern Recognition Abstract Nuclear magnetic resonance (NMR) spectral analysis has recently or more NMR spectra need to be compared, it is critical to properly align the spectra for the subsequent

  15. NMR Studies on a C-Methylated Dihydrochalcone from Pityrogramma triangularis Var. Viscosa

    Microsoft Academic Search

    Karl Egil Malterud

    1980-01-01

    The C NMR spectrum of the title substance and the H NMR spectrum of its silylated derivative are reported and discussed. ASIS analysis of the H NMR spectrum points to 4, 2?, 6?-trihydroxy-4?-methoxy-3?-methyldihydrochalcone as the correct structure.

  16. Structural Transitions in Short-Chain Lipid Assemblies Studied by P-NMR Spectroscopy

    E-print Network

    Kleinschmidt, Jörg H.

    Structural Transitions in Short-Chain Lipid Assemblies Studied by 31 P-NMR Spectroscopy Jo¨ rg HCnPG), and diacylphosphatidylserine (diCnPS) were investigated by 31 P nuclear magnetic resonance (NMR) spectroscopy as a function diacylphospholipid classes and the 31 P-NMR spectra provided evidence for a tubular network that appeared

  17. Scalar and anisotropic J interactions in undoped InP: A triple-resonance NMR study

    E-print Network

    Augustine, Mathew P.

    and can comple- ment optical studies.9,10 InP is a prominent example where ``anomalous'' 31 P NMR Engelsberg and Norberg's postulate that the 31 P NMR linewidth in InP is determined by the relative magnitudeScalar and anisotropic J interactions in undoped InP: A triple-resonance NMR study Marco Tomaselli

  18. Interaction between -Purothionin and Dimyristoylphosphatidylglycerol: P-NMR and Infrared Spectroscopic Study

    E-print Network

    Pezolet, Michel

    Interaction between -Purothionin and Dimyristoylphosphatidylglycerol: A 31 P-NMR and Infrared vesicles of dimyristoylphosphatidylglycerol (DMPG) was investigated by 31 P solid-state NMR and infrared are positively charged at neutral pH. The three-dimensional (3D) structure of purothionins has been solved by NMR

  19. Membrane Curvature Change Induced by an Antimicrobial Peptide Detected by 31P Exchange NMR

    E-print Network

    Hong, Mei

    Membrane Curvature Change Induced by an Antimicrobial Peptide Detected by 31P Exchange NMR P. A. B) of phosphocholine bilayers is investigated using one- (1D) and two-dimensional (2D) 31 P exchange NMR types of lipid bilayers. Thus, 31 P exchange NMR provides useful insights into the membrane

  20. 1D to 3D NMR study of microporous alumino-phosphate Cludia Moraisa,b

    E-print Network

    Paris-Sud XI, Université de

    ) From one- to two- and three-dimensional MAS NMR solid state experiments involving 31 P and 27 Al we-HMQC opens new possibilities in describing details of three dimensional bounded networks. Keywords: NMR, 31P they involve abundant and sensitive nuclei (27 Al, 31 P) high resolution solid state NMR is a tool of choice

  1. QUANTITATIVE SOLID-STATE 13C NMR SPECTROSCOPY OF ORGANIC MATTER FRACTIONS IN LOWLAND RICE SOILS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spin counting on solid-state **13C cross-polarization (CP) nuclear magnetic resonance (NMR) spectra of two humic fractions isolated from tropical lowland soils showed that only 32-81% of potential **13C NMR signal was detected. The observability of **13C NMR signal (Cobs) was higher in the mobile h...

  2. Solid-State Dipolar INADEQUATE NMR Spectroscopy with a Large Double-Quantum Spectral Width

    E-print Network

    Hong, Mei

    Solid-State Dipolar INADEQUATE NMR Spectroscopy with a Large Double-Quantum Spectral Width Mei Hong Academic Press Key Words: solid-state NMR; INADEQUATE; double-quan- tum; C7; dipolar recoupling. Recently, solid-state homonuclear double-quantum NMR spec- troscopy has been increasingly employed to obtain

  3. Western Gas Sands Project: Los Alamos NMR well-logging tool development

    Microsoft Academic Search

    J. A. Jackson; J. A. Brown; A. R. Koelle

    1982-01-01

    Major advances were made in all areas of the project. Two commercial laboratory NMR spectrometers for core studies were acquired and put into operation. A low-frequency NMR spectrometer was built for core measurements at the operating frequency of the logging tool. A permanent magnet laboratory mockup of the logging tool is being used to measure NMR properties of fluid in

  4. Field Demonstration of Slim-hole Borehole Nuclear Magnetic Resonance (NMR) Logging Tool for Groundwater Investigations

    Microsoft Academic Search

    D. Walsh; P. Turner; I. Frid; R. Shelby; E. D. Grunewald; E. Magnuson; J. J. Butler; C. D. Johnson; J. C. Cannia; D. A. Woodward; K. H. Williams

    2010-01-01

    Nuclear magnetic resonance (NMR) methods provide estimates of free and bound water content and hydraulic conductivity, which are critically important for groundwater investigations. Borehole NMR tools have been available and widely used in the oil industry for decades, but only recently have been designed for small diameter boreholes typical of groundwater investigations. Field tests of an 89-mm-diameter borehole NMR logging

  5. Two dimensional exchange NMR experiments of natural porous media with portable Halbach-Magnets

    Microsoft Academic Search

    Agnes Haber; Sabina Haber-Pohlmeier; Federico Casanova; Bernhard Blümich

    2010-01-01

    The characterization of pore space and connectivity in soils of different textures is one topic within Cluster A, Partial Project A1. For this purpose low field mobile NMR became a powerful tool following the development of portable NMR sensors for well logging. By now there are numerous applications of mobile NMR in materials analysis and chemical engineering where, for example,

  6. A Review of the Principles and Applications of the NMR Technique for Near-Surface Characterization

    NASA Astrophysics Data System (ADS)

    Behroozmand, Ahmad A.; Keating, Kristina; Auken, Esben

    2015-01-01

    This paper presents a comprehensive review of the recent advances in nuclear magnetic resonance (NMR) measurements for near-surface characterization using laboratory, borehole, and field technologies. During the last decade, NMR has become increasingly popular in near-surface geophysics due to substantial improvements in instrumentation, data processing, forward modeling, inversion, and measurement techniques. This paper starts with a description of the principal theory and applications of NMR. It presents a basic overview of near-surface NMR theory in terms of its physical background and discusses how NMR relaxation times are related to different relaxation processes occurring in porous media. As a next step, the recent and seminal near-surface NMR developments at each scale are discussed, and the limitations and challenges of the measurement are examined. To represent the growth of applications of near-surface NMR, case studies in a variety of different near-surface environments are reviewed and, as examples, two recent case studies are discussed in detail. Finally, this review demonstrates that there is a need for continued research in near-surface NMR and highlights necessary directions for future research. These recommendations include improving the signal-to-noise ratio, reducing the effective measurement dead time, and improving production rate of surface NMR (SNMR), reducing the minimum echo time of borehole NMR (BNMR) measurements, improving petrophysical NMR models of hydraulic conductivity and vadose zone parameters, and understanding the scale dependency of NMR properties.

  7. ODIN—Object-oriented Development Interface for NMR

    Microsoft Academic Search

    Thies H. Jochimsen; Michael von Mengershausen

    2004-01-01

    A cross-platform development environment for nuclear magnetic resonance (NMR) experiments is presented. It allows rapid prototyping of new pulse sequences and provides a common programming interface for different system types. With this object-oriented interface implemented in C++, the programmer is capable of writing applications to control an experiment that can be executed on different measurement devices, even from different manufacturers,

  8. Ultrafast two-dimensional NMR spectroscopy using constant acquisition gradients

    E-print Network

    Frydman, Lucio

    of such fast-switching scheme may also arise due to gradient-induced perineural stimulation. The present study magnetic resonance nD NMR plays a central role in numerous areas of contempo- rary research. It serves as a basis for numerous in vitro analy- ses of molecular structure and dynamics, and acts as a basic tool

  9. Strategies for Rapid NMR Rheometry by Magnetic Resonance Imaging Velocimetry

    PubMed

    Gibbs; Haycock; Frith; Ablett; Hall

    1997-03-01

    Strategies for NMR-based rheometry are discussed with particular attention given to ease of implementation, robustness, and measurement speed. The techniques are based on NMR velocimetry of Poiseuille flow, and together with measurements of the pressure drop, the velocimetric data may be processed to yield measures of the shear viscosity over the range of shear rates present in the Poiseuille flow field of the test fluid. Methods for NMR velocimetry are briefly reviewed, and three methods all based on the pulsed-field-gradient technique are compared experimentally; they involve (1) direct two-dimensional imaging of the tube cross section, (2) one-dimensional imaging of a Cartesian projection of the tube cross section followed by Abel inversion to obtain radial profiles, and (3) measurement of the bulk velocity spectrum of the tube cross section and conversion to the radial velocity profile. The second and third of these techniques allow the most rapid measurements (potentially less than one minute) and show promise for on-line NMR rheometry. PMID:9245359

  10. ECG gated NMR-CT for cardiovascular diseases

    SciTech Connect

    Nishikawa, J.; Ohtake, T.; Machida, K.; Iio, M.; Yoshimoto, N.; Sugimoto, T.

    1985-05-01

    The authors have been applying ECG gated NMR-CT to mainly patients with myocardial infarction (MI), and hypertrophic cardiomyopathy (HCM). Thirteen patients with MI, 8 with HCM and 5 without any heart diseases were studied by ECG gated NMR imaging (spin-echo technique, TR: depends on patient heart rate, TE: 35 and 70 msec.) with 0.35 T superconducting magnet. On NMR images (MRI), the authors examined the wall thickness, wall motion and T/sub 2/ relaxation time in the area of diseased myocardium. The lesions of old MI were depicted as the area of thin wall and T/sub 2/ relaxation time of those lesions were similar to the area of non-infarcted myocardium. The lesions of recent MI (up to 3.5 months from the recent attack) were shown as the same wall thickness as the non-infarcted myocardium and the area of prolonged T/sub 2/ relaxation time compared with that of non-infarcted myocardium. MRI demonstrated diffusely thick myocardium in all patients with HCM. T/sub 2/ relaxation time of the areas of HCM was almost the same as that of normal myocardium, and it's difference among each ventricular wall in patients with HCM was not statistically significant. The authors conclude that ECG gated NMR-CT offers 3-D morphological information of the heart without any contrast material nor radioisotopes. ECG gated MRI provides the useful informations to diagnose MI, especially in the differential diagnosis between old and recent MI.

  11. The fluorinated anesthetic halothane as a potential NMR biologic probe.

    PubMed

    Burt, C T; Moore, R R; Roberts, M F; Brady, T J

    1984-12-11

    Fluorinated anesthetics such as halothane preferentially partition into hydrophobic environments such as cell membranes. The 19F-NMR spectrum of halothane in a rat adenocarcinoma (with known altered lipid metabolism and membrane composition) shows an altered chemical shift pattern compared to the anesthetic in normal tissue. In eight tumor samples examined, the 19F-NMR spectra exhibit two distinct resonances, compared to a single resonance observed in normal tissues. This is explained by an enhanced or altered hydrophobic component in the tumor tissue giving rise to two discrete halothane environments. Another fluorinated anesthetic, isoflurane, shows similar behavior in distinguishing normal from diseased tissue. Given the large chemical shift range of fluorine and the inherent sensitivity of this nucleus, 19F-NMR spectra of fluorinated anesthetics can also be used to follow anesthetic degradation by the liver. The ability of fluorinated anesthetics to discriminate tissues and to monitor metabolic processes is potentially useful for in vivo 19F-NMR surface coil and imaging studies. PMID:6509092

  12. Amplification of Xenon NMR and MRI by remote detection

    SciTech Connect

    Moule, Adam J.; Spence, Megan M.; Han, Song-I.; Seeley, JulietteA.; Pierce, Kimberly L.; Saxena, Sunil; Pines, Alexander

    2003-03-31

    A novel technique is proposed in which a nuclear magneticresonance (NMR) spectrum or magnetic resonance image (MRI) is encoded andstored as spin polarization and is then moved to a different physicallocation to be detected. Remote detection allows the separateoptimization of the encoding and detection steps, permitting theindependent choice of experimental conditions, and excitation anddetection methodologies. In the first experimental demonstration of thistechnique, we show that NMR signal can be amplified by taking diluted129Xe from a porous sample placed inside a large encoding coil, andconcentrating it into a smaller detection coil. In general, the study ofNMR active molecules at low concentration that have low physical fillingfactor is facilitated by remote detection. In the second experiment, MRIinformation encoded in a very low field magnet (4-7mT) is transferred toa high field magnet (4.2 T) in order to be detected under optimizedconditions. Furthermore, remote detection allows the utilization ofultra-sensitive optical or superconducting detection techniques, whichbroadens the horizon of NMR experimentation.

  13. NMR Planar Micro coils for micro spectroscopy: Design and characterisation

    Microsoft Academic Search

    N. Baxan; A. Rengle; J.-F. Chateaux; A. Briguet; G. Pasquet; P. Morin; L. Fakri-Bouchet

    2006-01-01

    The goal of this study is to determine the concentration sensitivity and the limit of detection of a SNMR receiver planar micro coil with ellipsoidal geometry 1000times500 mum, fabricated using an electroplating technique and used as SNMR receiver coil at 200 MHz. The maximum signal intensity on the NMR images and simulation of RF field distribution allows defining an active

  14. Communication Interlaced Fourier transformation of ultrafast 2D NMR data

    E-print Network

    Frydman, Lucio

    ; Interlaced Fourier transformation; Signal-to-noise ratio; Sensitivity enhancement; Spectral resolution Two-dimensional is capable of dealing in a single, combined fashion, with the two mirror-imaged interferograms aris- ing the NMR pulse sequence, monitoring its effects requires the collection of several independent scans

  15. Artefacts and pitfalls in diffusion measurements by NMR

    Microsoft Academic Search

    Geir Humborstad Sørland; Dagfinn Aksnes

    2002-01-01

    When applying pulsed field gradient (PFG) NMR experiments to determine the molecular mobility characterized by the diffusion coefficient, it is crucial to have control over all experimental parameters that may affect the performance of the diffusion experiment. This could be diffusion measurement in the presence of magneticfield transients, internal magneticfield gradients, either constant or spatially varying, convection, mechanical vibrations, or

  16. 'Shim pulses' for NMR spectroscopy in inhomogeneous magneticfields

    Microsoft Academic Search

    Daniel Topgaard; Rachel W. Martin; Dimitris Sakellariou; Carlos Meriles; Alexander Pines

    2004-01-01

    NMR spectroscopy conveys information about chemical structure through ppm-scale shifts of the resonance frequency depending on the chemical environment. In order to observe these small shifts, magnets with highly homogeneous magnetic field Bâ are used. The high cost and large size of these magnets are a consequence of the requirement for high homogeneity. In this contribution we introduce a new

  17. Study of cultured fibroblasts in vivo using NMR

    SciTech Connect

    Karczmar, G.S.

    1984-01-01

    The goal of this thesis was to study the compartmentation of phosphorylated glycolytic intermediates in intact Chicken Embryo Fibroblasts (CEFs) using /sup 31/P NMR at 109 MHz. Because glycolysis is regulated differently in normal and virally transformed CEFs, NMR experiments were performed on both types of cells. A technique for maintaining functional cells at high densities in an NMR magnet is described. Signals were detected from cytoplasmic inorganic phosphate (P/sub i/), ATP, NAD, NADH, phosphorylcholine and phosphorylethanolamine. The effect of external glucose on cytoplasmic pools of phosphates was studied. However, experiments with /sup 32/P labelled P/sub i/ showed that as the concentration of glucose in the medium was increased, the amount of phosphate sequestered in the cells increased. They conclude that there is a pool of P/sub i/ which is not detected by high resolution of NMR and that the size of this pool increases as the rate of glycolysis increases. These effects were found only in cultured cells; the data for transformed and normal cells were similar. Longitudinal relaxation times of intracellular phosphates in normal, transformed, and primary CEFs were measured.

  18. Extended hopane derivatives in sediments - Identification by H-1 NMR

    NASA Technical Reports Server (NTRS)

    Taylor, J.; Wardroper, A. M. K.; Maxwell, J. R.

    1980-01-01

    Sedimentary C32 hopanoic acid, one of the most abundant in nature and of probable bacterial origin, has been isolated for the first time as a single component and characterized by H-1 NMR. The 17 alpha H, 21 beta H configuration of the C31 alkane has been similarly confirmed.

  19. Towards a NMR implementation of a quantum lattice gas algorithm

    Microsoft Academic Search

    Marco A. Pravia; Zhiying Chen; Jeffrey Yepez; David G. Cory

    2002-01-01

    Recent theoretical results suggest that an array of quantum information processors communicating via classical channels can be used to solve fluid dynamics problems. Quantum lattice-gas algorithms (QLGA) running on such architectures have been shown to solve the diffusion equation and the nonlinear Burgers equations. In this report, we describe progress towards an ensemble nuclear magnetic resonance (NMR) implementation of a

  20. A random graph approach to NMR sequential assignment

    Microsoft Academic Search

    Chris Bailey-Kellogg; Sheetal Chainraj; Gopal Pandurangan

    2004-01-01

    Nuclear magnetic resonance (NMR) spectroscopy allows scientists to study protein structure, dynamics, and interactions in solution. A necessary first step for such applications is determining the resonance assignment, mapping spectral data to atoms and residues in the primary sequence. Automated resonance assignment algorithms rely on information regarding connectivity (e.g. through-bond atomic interactions) and amino acid type, typically using the former

  1. Pulsed zero field NMR of solids and liquid crystals

    SciTech Connect

    Thayer, A.M.

    1987-02-01

    This work describes the development and applications to solids and liquid crystals of zero field nuclear magnetic resonance (NMR) experiments with pulsed dc magnetic fields. Zero field NMR experiments are one approach for obtaining high resolution spectra of amorphous and polycrystalline materials which normally (in high field) display broad featureless spectra. The behavior of the spin system can be coherently manipulated and probed in zero field with dc magnetic field pulses which are employed in a similar manner to radiofrequency pulses in high field NMR experiments. Nematic phases of liquid crystalline systems are studied in order to observe the effects of the removal of an applied magnetic field on sample alignment and molecular order parameters. In nematic phases with positive and negative magnetic susceptibility anisotropies, a comparison between the forms of the spin interactions in high and low fields is made. High resolution zero field NMR spectra of unaligned smectic samples are also obtained and reflect the symmetry of the liquid crystalline environment. These experiments are a sensitive measure of the motionally induced asymmetry in biaxial phases. Homonuclear and heteronuclear solute spin systems are compared in the nematic and smectic phases. Nonaxially symmetric dipolar couplings are reported for several systems. The effects of residual fields in the presence of a non-zero asymmetry parameter are discussed theoretically and presented experimentally. Computer programs for simulations of these and other experimental results are also reported. 179 refs., 75 figs.

  2. Investigations of silicone breast implants with the NMR-MOUSE

    Microsoft Academic Search

    Mirko Krüger; Annett Schwarz; Bernhard Blümich

    2007-01-01

    Silicone breast implants are used for breast augmentation and breast reconstruction. The issues of concern associated with such implants are: (a) the quality control of each implant before implantation, and (b) the detection of implant bleeding after implantation. We have studied the use of the Nuclear Magnetic Resonance–MObile Universal Surface Explorer (NMR-MOUSE) for the nondestructive testing of (a) the quality

  3. PROTEIN STRUCTURAL ANALYSIS FROM SOLID STATE NMR DERIVED ORIENTATIONAL CONSTRAINTS

    E-print Network

    Aluffi, Paolo

    PROTEIN STRUCTURAL ANALYSIS FROM SOLID STATE NMR DERIVED ORIENTATIONAL CONSTRAINTS J. R. QUINE provides a great structural analysis problem. Several approaches to this problem have been made in the past is demonstrated over the previous analysis methods. #12; PROTEIN STRUCTURAL ANALYSIS FROM ORIENTATIONAL

  4. Using NMR to Determine Protein Structure in Solution

    NASA Astrophysics Data System (ADS)

    Cavagnero, Silvia

    2003-02-01

    Nuclear magnetic resonance (NMR) is a marvelous spectroscopic technique that chemists, physicists, and biochemists routinely employ for their research around the world. This year half of the Nobel Prize for chemistry went to Kurt Wüthrich, who was recognized for the development of NMR-based techniques that lead to the structure determination of biomolecules in solution. In addition to implementing novel pulse sequences and software packages, Wüthrich also applied his methods to several biological systems of key importance to human health. These include the prion protein, which is heavily involved in the spongiform encephalopathy (best known as 'mad cow disease'), which recently caused numerous human deaths, particularly in the UK, due to ingestion of contaminated meat. Transverse relaxation optimized spectroscopy (TROSY) is the most intriguing new NMR method recently developed by Wüthrich and coworkers. This and other closely related pulse sequences promise to play a pivotal role in the extension of NMR to the conformational analysis of very large (up to the megadalton range) macromolecules and macromolecular complexes. More exciting new developments are expected in the near future.

  5. NMR and NQR study of the thermodynamically stable quasicrystals

    SciTech Connect

    Shastri, A.

    1995-02-10

    {sup 27}Al and {sup 61,65}Cu NMR measurements are reported for powder samples of stable AlCuFe and AlCuRu icosahedral quasicrystals and their crystalline approximants, and for a AlPdMn single grain quasicrystal. Furthermore, {sup 27}Al NQR spectra at 4.2 K have been observed in the AlCuFe and AlCuRu samples. From the quadrupole perturbed NMR spectra at different magnetic fields, and from the zero field NQR spectra, a wide distribution of local electric field gradient (EFG) tensor components and principal axis system orientations was found at the Al site. A model EFG calculation based on a 1/1 AlCuFe approximant was successful in explaining the observed NQR spectra. It is concluded that the average local gradient is largely determined by the p-electron wave function at the Al site, while the width of the distribution is due to the lattice contribution to the EFG. Comparison of {sup 63}Cu NMR with {sup 27}Al NMR shows that the EFG distribution at the two sites is similar, but that the electronic contribution to the EFG is considerably smaller at the Cu site, in agreement with a more s-type wave function of the conduction electrons.

  6. 1H NMR analysis of sporopollenin from Typha Angustifolia

    Microsoft Academic Search

    Friedhelm Ahlers; Ina Thom; Jörg Lambert; Rüdiger Kuckuk; Rolf Wiermann

    1999-01-01

    The first analysis of sporopollenin using 1H NMR-techniques revealed the presence of four phenolic compounds in different amounts. The phenolic compounds are tri- or tetrasubstituted. The sporopollenin was isolated and purified from Typha angustifolia by an enzymatic procedure, followed by extraction with organic solvents.

  7. NMR solution structure of the human prion protein

    Microsoft Academic Search

    Ralph Zahn; Aizhuo Liu; Thorsten Lührs; Roland Riek; Christine von Schroetter; Francisco López García; Martin Billeter; Luigi Calzolai; Gerhard Wider; Kurt Wüthrich

    2000-01-01

    The NMR structures of the recombinant human prion protein, hPrP(23-230), and two C-terminal fragments, hPrP(90-230) and hPrP(121-230), include a globular domain extending from residues 125-228, for which a detailed structure was obtained, and an N-terminal flexibly disordered \\

  8. MULTIVARIATE CURVE RESOLUTION OF NMR SPECTROSCOPY METABONOMIC DATA

    EPA Science Inventory

    Sandia National Laboratories is working with the EPA to evaluate and develop mathematical tools for analysis of the collected NMR spectroscopy data. Initially, we have focused on the use of Multivariate Curve Resolution (MCR) also known as molecular factor analysis (MFA), a tech...

  9. NMR of thin layers using a meanderline surface coil

    DOEpatents

    Cowgill, Donald F. (San Ramon, CA)

    2001-01-01

    A miniature meanderline sensor coil which extends the capabilities of nuclear magnetic resonance (NMR) to provide analysis of thin planar samples and surface layer geometries. The sensor coil allows standard NMR techniques to be used to examine thin planar (or curved) layers, extending NMRs utility to many problems of modern interest. This technique can be used to examine contact layers, non-destructively depth profile into films, or image multiple layers in a 3-dimensional sense. It lends itself to high resolution NMR techniques of magic angle spinning and thus can be used to examine the bonding and electronic structure in layered materials or to observe the chemistry associated with aging coatings. Coupling this sensor coil technology with an arrangement of small magnets will produce a penetrator probe for remote in-situ chemical analysis of groundwater or contaminant sediments. Alternatively, the sensor coil can be further miniaturized to provide sub-micron depth resolution within thin films or to orthoscopically examine living tissue. This thin-layer NMR technique using a stationary meanderline coil in a series-resonant circuit has been demonstrated and it has been determined that the flat meanderline geometry has about he same detection sensitivity as a solenoidal coil, but is specifically tailored to examine planar material layers, while avoiding signals from the bulk.

  10. NMR in rotating magnetic fields: Magic angle field spinning

    SciTech Connect

    Sakellariou, D.; Meriles, C.; Martin, R.; Pines, A.

    2004-09-10

    Magic angle sample spinning has been one of the cornerstones in high-resolution solid state NMR. Spinning frequencies nowadays have increased by at least one order of magnitude over the ones used in the first experiments and the technique has gained tremendous popularity. It is currently a routine procedure in solid-state NMR, high-resolution liquid-state NMR and solid-state MRI. The technique enhances the spectral resolution by averaging away rank 2 anisotropic spin interactions thereby producing isotropic-like spectra with resolved chemical shifts and scalar couplings. Andrew proposed that it should be possible to induce similar effects in a static sample if the direction of the magnetic field is varied, e.g., magic-angle rotation of the B0 field (B0-MAS) and this has been recently demonstrated using electromagnetic field rotation. Here we discuss on the possibilities to perform field rotation using alternative hardware, together with spectroscopic methods to recover isotropic resolution even in cases where the field is not rotating at the magic angle. Extension to higher magnetic fields would be beneficial in situations where the physical manipulation of the sample is inconvenient or impossible. Such situations occur often in materials or biomedical samples where ''ex-situ'' NMR spectroscopy and imaging analysis is needed.

  11. Exploiting image registration for automated resonance assignment in NMR.

    PubMed

    Strickland, Madeleine; Stephens, Thomas; Liu, Jian; Tjandra, Nico

    2015-06-01

    Analysis of protein NMR data involves the assignment of resonance peaks in a number of multidimensional data sets. To establish resonance assignment a three-dimensional search is used to match a pair of common variables, such as chemical shifts of the same spin system, in different NMR spectra. We show that by displaying the variables to be compared in two-dimensional plots the process can be simplified. Moreover, by utilizing a fast Fourier transform cross-correlation algorithm, more common to the field of image registration or pattern matching, we can automate this process. Here, we use sequential NMR backbone assignment as an example to show that the combination of correlation plots and segmented pattern matching establishes fast backbone assignment in fifteen proteins of varying sizes. For example, the 265-residue RalBP1 protein was 95.4 % correctly assigned in 10 s. The same concept can be applied to any multidimensional NMR data set where analysis comprises the comparison of two variables. This modular and robust approach offers high efficiency with excellent computational scalability and could be easily incorporated into existing assignment software. PMID:25828257

  12. Novel Dodecaarylporphyrins: Synthesis and Variable Temperature NMR Studies

    SciTech Connect

    Cancilla, Mark; Lebrilla, Carlito; Ma, Jian-Guo; Medforth, Craig J.; Muzzi, Cinzia M.; Shelnutt, John A.; Smith, Kevin M.; Voss, Lisa

    1999-05-05

    An investigation of the synthesis of novel dodecaarylporphyrins using the Suzuki coupling reaction of arylboronic acids with octabromotetraarylporphyrins is reported. Studies of the dynamic properties of these new porphyrins using variable temperature (VT) 1H NMR spectroscopy and molecular mechanics provide interesting insights into their dynamic properties, including the first determination of {beta} aryl rotation in a porphyrin system.

  13. NMR Studies of Biomass and its Reaction Products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biomass refers to biological material derived from living or recently living organisms, such as wood, agricultural products and wastes, and alcohol fuels. An increasingly popular R&D approach is to convert biomass into industrial polymers or chemicals. NMR is an excellent technique for the character...

  14. Development and use of a virtual NMR facility.

    PubMed

    Keating, K A; Myers, J D; Pelton, J G; Bair, R A; Wemmer, D E; Ellis, P D

    2000-03-01

    We have developed a "virtual NMR facility" (VNMRF) to enhance access to the NMR spectrometers in Pacific Northwest National Laboratory's Environmental Molecular Sciences Laboratory (EMSL). We use the term virtual facility to describe a real NMR facility made accessible via the Internet. The VNMRF combines secure remote operation of the EMSL's NMR spectrometers over the Internet with real-time videoconferencing, remotely controlled laboratory cameras, real-time computer display sharing, a Web-based electronic laboratory notebook, and other capabilities. Remote VNMRF users can see and converse with EMSL researchers, directly and securely control the EMSL spectrometers, and collaboratively analyze results. A customized Electronic Laboratory Notebook allows interactive Web-based access to group notes, experimental parameters, proposed molecular structures, and other aspects of a research project. This paper describes our experience developing a VNMRF and details the specific capabilities available through the EMSL VNMRF. We show how the VNMRF has evolved during a test project and present an evaluation of its impact in the EMSL and its potential as a model for other scientific facilities. All Collaboratory software used in the VNMRF is freely available from www.emsl.pnl.gov:2080/docs/collab. PMID:10698658

  15. Communications: Nanomagnetic shielding: High-resolution NMR in carbon allotropes

    Microsoft Academic Search

    Y. Kim; E. Abou-Hamad; A. Rubio; T. Gberg; A. V. Talyzin; D. Boesch; S. Aloni; A. Zettl; D. E. Luzzi; C. Goze-Bac

    2010-01-01

    The understanding and control of the magnetic properties of carbon-based materials is of fundamental relevance in applications in nano- and biosciences. Ring currents do play a basic role in those systems. In particular the inner cavities of nanotubes offer an ideal environment to investigate the magnetism of synthetic materials at the nanoscale. Here, by means of 13C high resolution NMR

  16. Noise figure characterization of preamplifiers at NMR frequencies

    NASA Astrophysics Data System (ADS)

    Nordmeyer-Massner, J. A.; De Zanche, N.; Pruessmann, K. P.

    2011-05-01

    A method for characterizing the noise figure of preamplifiers at NMR frequencies is presented. The noise figure of preamplifiers as used for NMR and MRI detection varies with source impedance and with the operating frequency. Therefore, to characterize a preamplifier's noise behavior, it is necessary to perform noise measurements at the targeted frequency while varying the source impedance with high accuracy. At high radiofrequencies, such impedance variation is typically achieved with transmission-line tuners, which however are not available for the relatively low range of typical NMR frequencies. To solve this issue, this work describes an alternative approach that relies on lumped-element circuits for impedance manipulation. It is shown that, using a fixed-impedance noise source and suitable ENR correction, this approach permits noise figure characterization for NMR and MRI purposes. The method is demonstrated for two preamplifiers, a generic BF998 MOSFET module and an MRI-dedicated, integrated preamplifier, which were both studied at 128 MHz, i.e., at the Larmor frequency of protons at 3 Tesla. Variations in noise figure of 0.01 dB or less over repeated measurements reflect high precision even for small noise figures in the order of 0.4 dB. For validation, large sets of measured noise figure values are shown to be consistent with the general noise-parameter model of linear two-ports. Finally, the measured noise characteristics of the superior preamplifier are illustrated by SNR measurements in MRI data.

  17. Improving magnetic field gradient coils for NMR imaging

    Microsoft Academic Search

    B. H. Suits; D. E. Wilken

    1989-01-01

    A general method of designing magnetic field gradient coils for NMR imaging is suggested and developed. The method utilises a combination of exact calculations for infinite continuous current sheets with a series expansion method to analyse finite discrete models of the continuous case. The method is applied to two orientations for coils on a cylindrical form resulting in improvements of

  18. Nondestructive NMR technique for moisture determination in radioactive materials.

    SciTech Connect

    Aumeier, S.; Gerald, R.E. II; Growney, E.; Nunez, L.; Kaminski, M.

    1998-12-04

    This progress report focuses on experimental and computational studies used to evaluate nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) for detecting, quantifying, and monitoring hydrogen and other magnetically active nuclei ({sup 3}H, {sup 3}He, {sup 239}Pu, {sup 241}Pu) in Spent nuclear fuels and packaging materials. The detection of moisture by using a toroid cavity NMR imager has been demonstrated in SiO{sub 2} and UO{sub 2} systems. The total moisture was quantified by means of {sup 1}H NMR detection of H{sub 2}O with a sensitivity of 100 ppm. In addition, an MRI technique that was used to determine the moisture distribution also enabled investigators to discriminate between bulk and stationary water sorbed on the particles. This imaging feature is unavailable in any other nondestructive assay (NDA) technique. Following the initial success of this program, the NMR detector volume was scaled up from the original design by a factor of 2000. The capacity of this detector exceeds the size specified by DOE-STD-3013-96.

  19. Time-of-Flight Flow Imaging Using NMR Remote Detection

    Microsoft Academic Search

    Josef Granwehr; Elad Harel; Song-I Han; Sandra Garcia; Alex Pines; Pabitra N. Sen; Yi-Qiao Song

    2005-01-01

    A time-of-flight imaging technique is introduced to visualize fluid flow and dispersion through porous media using NMR. As the fluid flows through a sample, the nuclear spin magnetization is modulated by rf pulses and magnetic field gradients to encode the spatial coordinates of the fluid. When the fluid leaves the sample, its magnetization is recorded by a second rf coil.

  20. Biomedical Applications of NMR Imaging and Diffusion Studies

    E-print Network

    Walsworth, Ronald L.

    ; Hyperpolarized noble gas; Hyperpolarized 129 Xe MRI; PGSE technique; Gas diffusion; Restricted diffusion; PorousBiomedical Applications of NMR Imaging and Diffusion Studies Using Thermal And Hyperpolarized Xenon Studies Using Thermal And Hyperpolarized Xenon by Sameer Anil Sheth Submitted to the Department of Physics

  1. NMR Characterization of Substituted Aromatic Poly (Ether Sulofone)s

    Microsoft Academic Search

    Frederick H. Roos; William H. Daly; Marietta N. Aniano-Ilao; Ioan I. Negulescu

    1996-01-01

    The synthesis of a variety of substituted bisphenol A polysulfones, including nitro, amino, aminomethyl, ethyl, and methyl derivatives, is described. Nuclear magnetic resonance (NMR) (both proton and carbon, and several 2-D experiments) data confirm conclusions on the substitution site based on arguments on inductive effects in the phenyl rings. The proton ortho to the oxygen in the bisphenol A (BPA)

  2. Efficient NMR enantiodifferentiation of chiral quats with BINPHAT anion.

    PubMed

    Lacour, Jérôme; Vial, Laurent; Herse, Christelle

    2002-04-18

    Hexacoordinated phosphorus BINPHAT anion is an efficient NMR chiral shift agent for quaternary ammonium cations (quats) leading to large separations (DeltaDeltadelta up to 0.29 ppm) of the proton signals of the enantiomers. [reaction: see text] PMID:11950360

  3. Journal of Biomolecular NMR, 20: 1114, 2001. KLUWER/ESCOM

    E-print Network

    Zhou, Pei

    direct NMR studies of the fusion proteins. Cleavage of the fusion proteins often re-introduces problems February 2001 Key words: protein G, protein stabilization, protein tag Abstract Protein-fusion constructs the solubility and stability of the fusion product dramatically while not interacting directly with the protein

  4. Plastic NMR Tubes and Reactor Systems for Handling Fluorine Compounds

    Microsoft Academic Search

    Christian A. Wamser; Burch B. Stewart

    1965-01-01

    A PLAST~C sample tube, which possesses adequate magnetlc transparency, has been develotJed and used extensively in these laboratories for !9F NMR analysis of corrosive fluorine compounds not requiring spinning. The plastic material found most suitable is translucent poly­ trifluorochloroethylene, preferably a modified type such as Allied Chemical \\

  5. Spectral Editing in 13 C MAS NMR under Moderately Fast

    E-print Network

    Frydman, Lucio

    Spectral Editing in 13 C MAS NMR under Moderately Fast Spinning Conditions1 Enrico De Vita-angle spinning (10­14 kHz MAS), CH and CH2 moieties behave to a large extent as if they were effectively isolated), magic-angle spinning (MAS), and efficient forms of proton decoupling has made the acquisition of 13 C

  6. Solid-State NMR Spectroscopy for the Physical Chemistry Laboratory

    ERIC Educational Resources Information Center

    Kinnun, Jacob J.; Leftin, Avigdor; Brown, Michael F.

    2013-01-01

    Solid-state nuclear magnetic resonance (NMR) spectroscopy finds growing application to inorganic and organic materials, biological samples, polymers, proteins, and cellular membranes. However, this technique is often neither included in laboratory curricula nor typically covered in undergraduate courses. On the other hand, spectroscopy and…

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

    Microsoft Academic Search

    George J. Hirasaki; Kishore K. Mohanty; K. Kishore

    2001-01-01

    The objective of this project is to characterize the fluid properties and fluid-rock interactions that are needed for formation evaluation by NMR well logging. This is the first annual progress report submitted to the DOE. It reports on the work completed during the reporting period even if it may have started before this period. This project is a partnership between

  8. Optimal control in NMR spectroscopy: Numerical implementation in SIMPSON

    NASA Astrophysics Data System (ADS)

    Tošner, Zden?k; Vosegaard, Thomas; Kehlet, Cindie; Khaneja, Navin; Glaser, Steffen J.; Nielsen, Niels Chr.

    2009-04-01

    We present the implementation of optimal control into the open source simulation package SIMPSON for development and optimization of nuclear magnetic resonance experiments for a wide range of applications, including liquid- and solid-state NMR, magnetic resonance imaging, quantum computation, and combinations between NMR and other spectroscopies. Optimal control enables efficient optimization of NMR experiments in terms of amplitudes, phases, offsets etc. for hundreds-to-thousands of pulses to fully exploit the experimentally available high degree of freedom in pulse sequences to combat variations/limitations in experimental or spin system parameters or design experiments with specific properties typically not covered as easily by standard design procedures. This facilitates straightforward optimization of experiments under consideration of rf and static field inhomogeneities, limitations in available or desired rf field strengths (e.g., for reduction of sample heating), spread in resonance offsets or coupling parameters, variations in spin systems etc. to meet the actual experimental conditions as close as possible. The paper provides a brief account on the relevant theory and in particular the computational interface relevant for optimization of state-to-state transfer (on the density operator level) and the effective Hamiltonian on the level of propagators along with several representative examples within liquid- and solid-state NMR spectroscopy.

  9. Journal of Biomolecular NMR, 14: 7174, 1999. KLUWER/ESCOM

    E-print Network

    Hong, Mei

    ; Accepted 8 February 1999 Key words: colicin Ia, double-quantum filter, isotopic labeling, resonance. Printed in the Netherlands. 71 Selective and extensive 13 C labeling of a membrane protein for solid assignment, solid-state NMR Abstract The selective and extensive 13C labeling of mostly hydrophobicamino acid

  10. Structural NMR of Protein Oligomers using Hybrid Methods

    PubMed Central

    Wang, Xu; Lee, Hsiau-Wei; Liu, Yizhou; Prestegard, James H.

    2010-01-01

    Solving structures of native oligomeric protein complexes using traditional high resolution NMR techniques remains challenging. However, increased utilization of computational platforms, and integration of information from less traditional NMR techniques with data from other complementary biophysical methods, promises to extend the boundary of NMR-applicable targets. This article reviews several of the techniques capable of providing less traditional and complementary structural information. In particular, the use of orientational constraints coming from residual dipolar couplings and residual chemical shift anisotropy offsets are shown to simplify the construction of models for oligomeric complexes, especially in cases of weak homo-dimers. Combining this orientational information with interaction site information supplied by computation, chemical shift perturbation, paramagnetic surface perturbation, cross-saturation and mass spectrometry allows high resolution models of the complexes to be constructed with relative ease. Non-NMR techniques, such as mass spectrometry, EPR and small angle X-ray scattering, are also expected to play increasingly important roles by offering alternative methods of probing the overall shape of the complex. Computational platforms capable of integrating information from multiple sources in the modeling process are also discussed in the article. And finally a new, detailed example on the determination of a chemokine tetramer structure will be used to illustrate how a non-traditional approach to oligomeric structure determination works in practice. PMID:21074622

  11. COMMUNICATION GFT projection NMR based resonance assignment of membrane

    E-print Network

    Yates, Andrew

    chain shifts. Moreover, the use of two G2 FT NMR experiments, that is, (5,3)D HN{N,CO}{Cab Ca } and (5,3)D {Cab Ca } {CON}HN, was explored to break the very high chemical shift degeneracy typically proteome are membrane proteins, which are pivotal for living cellular systems and constitute 60

  12. Protonproton Overhauser NMR spectroscopy with polypeptide chains in large structures

    E-print Network

    Wider, Gerhard

    ¨ rich, Switzerland; §Howard Hughes Medical Institute and Department of Genetics, Yale University School maromolecular assemblies in solution. 1H­1H NOE GroE chaperonine system NMR assignments protein structure connectivities for sequential assignment of the backbone 1 HN , 15 N, 13 C , and 13 CO resonances (1

  13. The DFRC Method for Lignin Analysis. Part 3. NMR Studies

    Microsoft Academic Search

    Fachuang Lu; John Ralph

    1998-01-01

    Two key reactions in the DFRC method have been examined by NMR. Both acetyl bromide (AcBr) derivatization of lignin and Zn reductive elimination of the ?-bromo derivatives from lignin were highly selective and essentially quantitative. Treatment with AcBr in acetic acid efficiently converted ?-aryl ether substructures of lignins into ?-bromo ethers while ?-hydroxy and phenol groups were acetylated; the following

  14. Two Phase Flow Measurements by Nuclear Magnetic Resonance (NMR)

    SciTech Connect

    Altobelli, Stephen A; Fukushima, Eiichi

    2006-08-14

    In concentrated suspensions, there is a tendency for the solid phase to migrate from regions of high shear rate to regions of low shear (Leighton & Acrivos, 1987). In the early years that our effort was funded by the DOE Division of Basic Energy Science, quantitative measurement of this process in neutrally buoyant suspensions was a major focus (Abbott, et al., 1991; Altobelli, et al., 1991). Much of this work was used to improve multi-phase numerical models at Sandia National Laboratories. Later, our collaborators at Sandia and the University of New Mexico incorporated body forces into their numerical models of suspension flow (Rao, Mondy, Sun, et al., 2002). We developed experiments that allow us to study flows driven by buoyancy, to characterize these flows in well-known and useful engineering terms (Altobelli and Mondy, 2002) and to begin to explore the less well-understood area of flows with multiple solid phases (Beyea, Altobelli, et al., 2003). We also studied flows that combine the effects of shear and buoyancy, and flows of suspensions made from non-Newtonian liquids (Rao, Mondy, Baer, et al, 2002). We were able to demonstrate the usefulness of proton NMR imaging of liquid phase concentration and velocity and produced quantitative data not obtainable by other methods. Fluids flowing through porous solids are important in geophysics and in chemical processing. NMR techniques have been widely used to study liquid flow in porous media. We pioneered the extension of these studies to gas flows (Koptyug, et al, 2000, 2000, 2001, 2002). This extension allows us to investigate a wider range of Peclet numbers, and to gather data on problems of interest in catalysis. We devised two kinds of NMR experiments for three-phase systems. Both experiments employ two NMR visible phases and one phase that gives no NMR signal. The earlier method depends on the two visible phases differing in a NMR relaxation property. The second method (Beyea, Altobelli, et al., 2003) uses two different nuclei, protons and 19F. It also uses two different types of NMR image formation, a conventional spin-echo and a single-point method. The single-point method is notable for being useful for imaging materials which are much more rigid than can usually be studied by NMR imaging. We use it to image “low density” polyethylene (LDPE) plastic in this application. We have reduced the imaging time for this three-phase imaging method to less than 10 s per pair of profiles by using new hardware. Directly measuring the solid LDPE signal was a novel feature for multi-phase flow studies. We also used thermally polarized gas NMR (as opposed to hyper-polarized gas) which produces low signal to noise ratios because gas densities are on the order of 1000 times smaller than liquid densities. However since we used multi-atom molecules that have short T1's and operated at elevated pressures we could overcome some of the losses. Thermally polarized gases have advantages over hyperpolarized gases in the ease of preparation, and in maintaining a well-defined polarization. In these studies (Codd and Altobelli, 2003), we used stimulated echo sequences to successfully obtain propagators of gas in bead packs out to observation times of 300 ms. Zarraga, et al. (2000) used laser-sheet profilometry to investigate normal stress differences in concentrated suspensions. Recently we developed an NMR imaging analog for comparison with numerical work that is being performed by Rekha Rao at Sandia National Laboratories (Rao, Mondy, Sun, et al, 2002). A neutrally buoyant suspension of 100 mm PMMA spheres in a Newtonian liquid was sheared in a vertical Couette apparatus inside the magnet. The outer cylinder rotates and the inner cylinder is fixed. At these low rotation rates, the free-surface of the Newtonian liquid shows no measurable deformation, but the suspension clearly shows its non-Newtonian character.

  15. Toxic actions of dinoseb in medaka ( Oryzias latipes) embryos as determined by in vivo 31P NMR, HPLC-UV and 1H NMR metabolomics

    Microsoft Academic Search

    Mark R. Viant; Christopher A. Pincetich; David E. Hinton; Ronald S. Tjeerdema

    2006-01-01

    Changes in metabolism of Japanese medaka (Oryzias latipes) embryos exposed to dinoseb (2-sec-butyl-4,6-dinitrophenol), a substituted dinitrophenol herbicide, were determined by in vivo 31P NMR, high-pressure liquid chromatography (HPLC)-UV, and 1H NMR metabolomics. ATP and phosphocreatine (PCr) metabolism were characterized within intact embryos by in vivo 31P NMR; concentrations of ATP, GTP, ADP, GDP, AMP and PCr were determined by HPLC-UV;

  16. Study of correlations in molecular motion by multiple quantum NMR

    SciTech Connect

    Tang, J.H.

    1981-11-01

    Nuclear magnetic resonance is a very useful tool for characterizing molecular configurations through the measurement of transition frequencies and dipolar couplings. The measurement of spectral lineshapes, spin-lattice relaxation times, and transverse relaxation times also provide us with valuable information about correlations in molecular motion. The new technique of multiple quantum nuclear magnetic resonance has numerous advantages over the conventional single quantum NMR techniques in obtaining information about static and dynamic interactions of coupled spin systems. In the first two chapters, the theoretical background of spin Hamiltonians and the density matrix formalism of multiple quantum NMR is discussed. The creation and detection of multiple quantum coherence by multiple pulse sequence are discussed. Prototype multiple quantum spectra of oriented benzene are presented. Redfield relaxation theory and the application of multiple quantum NMR to the study of correlations in fluctuations are presented. A specific example of an oriented methyl group relaxed by paramagnetic impurities is studied in detail. The study of possible correlated motion between two coupled methyl groups by multiple quantum NMR is presented. For a six spin system it is shown that the four-quantum spectrum is sensitive to two-body correlations, and serves a ready test of correlated motion. The study of the spin-lattice dynamics of orienting or tunneling methyl groups (CH/sub 3/ and CD/sub 3/) at low temperatures is presented. The anisotropic spin-lattice relaxation of deuterated hexamethylbenzene, caused by the sixfold reorientation of the molecules, is investigated, and the NMR spectrometers and other experimental details are discussed.

  17. Overhauser Dynamic Nuclear Polarization-Enhanced NMR Relaxometry.

    PubMed

    Franck, John M; Kausik, Ravinath; Han, Songi

    2013-09-15

    We present a new methodological basis for selectively illuminating a dilute population of fluid within a porous medium. Specifically, transport in porous materials can be analyzed by now-standard nuclear magnetic resonance (NMR) relaxometry and NMR pulsed field gradient (PFG) diffusometry methods in combination with with the prominent NMR signal amplification tool, dynamic nuclear polarization (DNP). The key components of the approach introduced here are (1) to selectively place intrinsic or extrinsic paramagnetic probes at the site or local volume of interest within the sample, (2) to amplify the signal from the local solvent around the paramagnetic probes with Overhauser DNP, which is performed in situ and under ambient conditions, and (3) to observe the ODNP-enhanced solvent signal with 1D or 2D NMR relaxometry methods, thus selectively amplifying only the relaxation dynamics of the fluid that resides in or percolates through the local porous volume that contains the paramagnetic probe. Here, we demonstrate the proof of principle of this approach by selectively amplifying the NMR signal of only one solvent population, which is in contact with a paramagnetic probe and occluded from a second solvent population. An apparent one-component T 2 relaxation decay is shown to actually contain two distinct solvent populations. The approach outlined here should be universally applicable to a wide range of other 1D and 2D relaxometry and PFG diffusometry measurements, including T 1-T 2 or T 1-D correlation maps, where the occluded population containing the paramagnetic probes can be selectively amplified for its enhanced characterization. PMID:23837010

  18. Recent progress in NMR/MRI in petroleum applications

    NASA Astrophysics Data System (ADS)

    Song, Yi-Qiao

    2007-03-01

    NMR has become an important technique for characterization of porous materials. In particular, its importance in petroleum exploration has been enhanced by the recent progress in NMR well-logging techniques and instruments. Such advanced techniques are increasing being accepted as a valuable service especially in deep-sea exploration. This paper will outline the recent progress of MR techniques at Schlumberger-Doll Research. Well-logging - The second generation NMR well-logging tool and the 2D NMR methods (D-T2, etc) enable measurements at several depths from the well bore allowing a one-dimensional profiling of the fluid. Such data have allowed quantification of fluid invasion during drilling, obtaining the properties of native fluids and identifying oil/gas zones. MRI- Rocks from oil reservoirs are heterogeneous (e.g. large range of pore sizes and porosity variation) due to the complex geological and geochemical histories. The spatial pattern of the heterogeneity has not been well studied. We have developed several NMR techniques to quantify pore length scale previously. In order to predict flow over a large length scale, it is necessary to determine spatial heterogeneity and pore connectivity over the relevant size. We have performed MRI on a series of carbonate rocks and found interesting patterns of the heterogeneity characteristics. Mathematics - It is well known that the Laplace inversion is non-unique and the resulting spectrum can be strongly dependent on the prior constraints, specific algorithm and noise. However, the different spectra can all be solutions consistent with data. It would be useful to have a robust criterion -- independent of algorithms -- to determine the properties of the resulting spectrum. Several methods will be described to examine the statistics of the solutions, uncertainty of the spectrum and its integrals and resolution.

  19. Overhauser Dynamic Nuclear Polarization-Enhanced NMR Relaxometry

    PubMed Central

    Franck, John M.; Kausik, Ravinath; Han, Songi

    2013-01-01

    We present a new methodological basis for selectively illuminating a dilute population of fluid within a porous medium. Specifically, transport in porous materials can be analyzed by now-standard nuclear magnetic resonance (NMR) relaxometry and NMR pulsed field gradient (PFG) diffusometry methods in combination with with the prominent NMR signal amplification tool, dynamic nuclear polarization (DNP). The key components of the approach introduced here are (1) to selectively place intrinsic or extrinsic paramagnetic probes at the site or local volume of interest within the sample, (2) to amplify the signal from the local solvent around the paramagnetic probes with Overhauser DNP, which is performed in situ and under ambient conditions, and (3) to observe the ODNP-enhanced solvent signal with 1D or 2D NMR relaxometry methods, thus selectively amplifying only the relaxation dynamics of the fluid that resides in or percolates through the local porous volume that contains the paramagnetic probe. Here, we demonstrate the proof of principle of this approach by selectively amplifying the NMR signal of only one solvent population, which is in contact with a paramagnetic probe and occluded from a second solvent population. An apparent one-component T2 relaxation decay is shown to actually contain two distinct solvent populations. The approach outlined here should be universally applicable to a wide range of other 1D and 2D relaxometry and PFG diffusometry measurements, including T1–T2 or T1-D correlation maps, where the occluded population containing the paramagnetic probes can be selectively amplified for its enhanced characterization. PMID:23837010

  20. Could smaller really be better? Current and future trends in high-resolution microcoil NMR spectroscopy.

    PubMed

    Jones, Christopher J; Larive, Cynthia K

    2012-01-01

    NMR is an invaluable analytical technique that provides structural and chemical information about a molecule without destroying the sample. However, NMR suffers from an inherent lack of sensitivity compared to other popular analytical techniques. This trends article focuses on strategies to increase the sensitivity of NMR using solenoidal microcoil, microstrip, and microslot probes. The role of these reduced-volume receiver coils for detection in hyphenated capillary electrophoresis (CE) and capillary isotachophoresis (cITP) NMR experiments is discussed. Future directions will likely build on work to develop probes containing multiple coils for high-throughput NMR and field-portable instruments. PMID:21879299

  1. Sensitization of a stray-field NMR to vibrations: A potential for MR elastometry with a portable NMR sensor

    NASA Astrophysics Data System (ADS)

    Mastikhin, Igor; Barnhill, Marie

    2014-11-01

    An NMR signal from a sample in a constant stray field of a portable NMR sensor is sensitized to vibrations. The CPMG sequence is synchronized to vibrations so that the constant gradient becomes an "effective" square-wave gradient, leading to the vibration-induced phase accumulation. The integrating nature of the spot measurement, combined with the phase distribution due to a non-uniform gradient and/or a wave field, leads to a destructive interference, the drop in the signal intensity and changes in the echo train shape. Vibrations with amplitudes as small as 140 nm were reliably detected with the permanent gradient of 12.4 T/m. The signal intensity depends on the phase offset between the vibrations and the pulse sequence. This approach opens the way for performing elastometry and micro-rheology measurements with portable NMR devices beyond the walls of a laboratory. Even without synchronization, if a vibration frequency is comparable to 1/2TE of the CPMG sequence, the signal can be severely affected, making it important for potential industrial applications of stray-field NMR.

  2. Development of a micro flow-through cell for high field NMR spectroscopy.

    SciTech Connect

    Alam, Todd Michael; McIntyre, Sarah K.

    2011-05-01

    A highly transportable micro flow-through detection cell for nuclear magnetic resonance (NMR) spectroscopy has been designed, fabricated and tested. This flow-through cell allows for the direct coupling between liquid chromatography (LC) and gel permeation chromatography (GPC) resulting in the possibility of hyphenated LC-NMR and GPC-NMR. The advantage of the present flow cell design is that it is independent and unconnected to the detection probe electronics, is compatible with existing commercial high resolution NMR probes, and as such can be easily implemented at any NMR facility. Two different volumes were fabricated corresponding to between {approx}3.8 and 10 {micro}L detection volume. Examples of the performance of the cell on different NMR instruments, and using different NMR detection probes were demonstrated.

  3. Solid State Nuclear Magnetic Resonance 29 (2006) 191198 Towards rapid throughput NMR studies of full wine bottles

    E-print Network

    Augustine, Mathew P.

    2006-01-01

    been pursued. This marriage of NMR and MRI has led to the development of functional MRI [5] and NMR specific vintages and types of French wine. In a similar vein high field high resolution NMR spectroscopy wine samples but with a different focus from the small sample study mentioned above. Specifically, NMR

  4. NightShift: NMR shift inference by general hybrid model training - a framework for NMR chemical shift prediction

    PubMed Central

    2013-01-01

    Background NMR chemical shift prediction plays an important role in various applications in computational biology. Among others, structure determination, structure optimization, and the scoring of docking results can profit from efficient and accurate chemical shift estimation from a three-dimensional model. A variety of NMR chemical shift prediction approaches have been presented in the past, but nearly all of these rely on laborious manual data set preparation and the training itself is not automatized, making retraining the model, e.g., if new data is made available, or testing new models a time-consuming manual chore. Results In this work, we present the framework NightShift (NMR Shift Inference by General Hybrid Model Training), which enables automated data set generation as well as model training and evaluation of protein NMR chemical shift prediction. In addition to this main result – the NightShift framework itself – we describe the resulting, automatically generated, data set and, as a proof-of-concept, a random forest model called Spinster that was built using the pipeline. Conclusion By demonstrating that the performance of the automatically generated predictors is at least en par with the state of the art, we conclude that automated data set and predictor generation is well-suited for the design of NMR chemical shift estimators. The framework can be downloaded from https://bitbucket.org/akdehof/nightshift. It requires the open source Biochemical Algorithms Library (BALL), and is available under the conditions of the GNU Lesser General Public License (LGPL). We additionally offer a browser-based user interface to our NightShift instance employing the Galaxy framework via https://ballaxy.bioinf.uni-sb.de/. PMID:23496927

  5. Miniature NMR spectrometer to analyse minerals at Mars

    NASA Astrophysics Data System (ADS)

    de Morais Mendonca Teles, Antonio

    There are some equipments and apparatuses for the study of interesting astrobiological places as planet Mars and moons Europa, Titan and Enceladus. As for Mars, some robotic missions have already analyzed its atmosphere and surface, using equipment with resolution down to milimetric scale. The NASA's Opportunity and Spirit rovers used microscope to study the sub-surface of the red planet at milimetric depth in drilled holes on rocks. In 1996, a NASA team announced the finding of organic molecules and morphological structures at nanometric scale, inside a meteorite which came from Mars. These possibly could be derived from an ancient Martian signature of biochemical activity, hypothetically, a fossilized `Archae-type' microorgan-ism. . In order to be acquired better resolutions for the mineralogical study of samples of its surface, it is necessary the use of nuclear magnetic resonance (NMR) spectrometers, with which one can obtain detailed astrobiological information below micrometer scale. NMR spectrome-ters are big equipment, but there are already miniature, lightweight, NMR spectrometers being developed which do not contain permanent magnets -they are designed to operate without applied magnetic fields; instead, they exploit the natural magnetic fields of the mineral phases (that contain iron) to be studied. These fields give rise to nuclear magnetic resonance of the isotope 57Fe at frequencies in the approximate range of 60 to 74 MHz. Such instrument has a mass of only 65 g (battery included) and consumes a power of only 0.2 W. It will be interesting the use of NMR spectroscopy at Mars. So, here in this paper, with the objective of the search for hypothetical extinct or extant life on Mars, I propose that in future robotic missions and a possible manned research at Mars, to be used miniature NMR spectrometers -rovers can have at the end of their robotic arms such those spectrometers and also astronauts can use those miniature NMR spectrometers to in-situ do very good quality research of surface and subsurface minerals, searching for organic molecules and morphological structures interestingly relevant for astrobiology.

  6. N NMR study of (pyrrolidine-2,2-diyl)bisphosphonic acid, tetraalkyl(pyrrolidine-2,2-diyl)bisphosphonates and acyclic tetraethyl

    E-print Network

    Boyer, Edmond

    A 1 H, 13 C, 31 P and 15 N NMR study of (pyrrolidine-2,2-diyl)bisphosphonic acid, tetraalkyl-381" #12;ABSTRACT: A multinuclear NMR study (1 H, 13 C, 31 P, 15 N) was performed on a series of new cyclic shifts and coupling constants of the various nuclei. KEYWORDS: NMR; 1 H NMR; 13 C NMR; 31 P NMR; 15 N NMR

  7. A Hall effect angle detector for solid-state NMR

    NASA Astrophysics Data System (ADS)

    Mamone, Salvatore; Dorsch, André; Johannessen, Ole G.; Naik, Manoj V.; Madhu, P. K.; Levitt, Malcolm H.

    2008-01-01

    We describe a new method for independent monitoring of the angle between the spinning axis and the magnetic field in solid-state NMR. A Hall effect magnetic flux sensor is fixed to the spinning housing, so that a change in the stator orientation leads to a change in the angle between the Hall plane and the static magnetic field. This leads to a change in the Hall voltage generated by the sensor when an electric current is passed through it. The Hall voltage may be measured externally by a precision voltmeter, allowing the spinning angle to be measured non-mechanically and independent of the NMR experiment. If the Hall sensor is mounted so that the magnetic field is approximately parallel to the Hall plane, the Hall voltage becomes highly sensitive to the stator orientation. The current angular accuracy is around 10 millidegrees. The precautions needed to achieve higher angular accuracy are described.

  8. Toward optimal-resolution NMR of intrinsically disordered proteins

    NASA Astrophysics Data System (ADS)

    Nová?ek, Ji?í; Žídek, Lukáš; Sklená?, Vladimír

    2014-04-01

    Proteins, which, in their native conditions, sample a multitude of distinct conformational states characterized by high spatiotemporal heterogeneity, most often termed as intrinsically disordered proteins (IDPs), have become a target of broad interest over the past 15 years. With the growing evidence of their important roles in fundamental cellular processes, there is an urgent need to characterize the conformational behavior of IDPs at the highest possible level. The unique feature of NMR spectroscopy in the context of IDPs is its ability to supply details of their structural and temporal alterations at atomic-level resolution. Here, we briefly review recently proposed NMR-based strategies to characterize transient states populated by IDPs and summarize the latest achievements and future prospects in methodological development. Because low chemical shift dispersion represents the major obstacle encountered when studying IDPs by nuclear magnetic resonance, particular attention is paid to techniques allowing one to approach the physical limits of attainable resolution.

  9. Susceptibility-matched plugs for microcoil NMR probes

    PubMed Central

    Kc, Ravi; Gowda, Yashas N.; Djukovic, Danijel; Henry, Ian D; Park, Gregory H J; Raftery, Daniel

    2010-01-01

    For mass limited samples, the residual sample volume outside the detection coil is an important concern, as is good base line resolution. Here, we present the construction and evaluation of magnetic susceptibility-matched plugs for microcoil NMR sample cells which address these issues. Mixed-epoxy glue and ultem tube plugs that have susceptibility values close to those of perfluorocarbon FC-43 (fluorinert) and copper were used in small volume (0.5 to 2 ?L) and larger volume (15 to 20 ?L) thin glass capillary sample cells. Using these plugs, the sample volume efficiency (i.e. ratio of active volume to total sample volume in the microcoil NMR cell) was improved by 6 to 12 fold without sensitivity and resolution trade-offs. Comparison with laser etched or heat etched microcoil sample cells is provided. The approaches described are potentially useful in metabolomics for biomarkers detection in mass limited biological samples. PMID:20510638

  10. Application of NMR metabolomics to search for human disease biomarkers.

    PubMed

    Gebregiworgis, Teklab; Powers, Robert

    2012-09-01

    Since antiquity, humans have used body fluids like saliva, urine and sweat for the diagnosis of diseases. The amount, color and smell of body fluids are still used in many traditional medical practices to evaluate an illness and make a diagnosis. The development and application of analytical methods for the detailed analysis of body fluids has led to the discovery of numerous disease biomarkers. Recently, mass spectrometry (MS), nuclear magnetic resonance spectroscopy (NMR), and multivariate statistical techniques have been incorporated into a multidisciplinary approach to profile changes in small molecules associated with the onset and progression of human diseases. The goal of these efforts is to identify metabolites that are uniquely correlated with a specific human disease in order to accurately diagnose and treat the malady. In this review we will discuss recent developments in sample preparation, experimental techniques, the identification and quantification of metabolites, and the chemometric tools used to search for biomarkers of human diseases using NMR. PMID:22480238

  11. Simulation of the Burgers equation by NMR quantum information processing

    E-print Network

    Zhiying Chen; Jeffrey Yepez; David G. Cory

    2004-10-25

    We report on the implementation of Burgers equation as a type-II quantum computation on an NMR quantum information processor. Since the flow field evolving under the Burgers equation develops sharp features over time, this is a better test of liquid state NMR implementations of type-II quantum computers than the previous examples using the diffusion equation. In particular, we show that Fourier approximations used in the encoding step are not the dominant error. Small systematic errors in the collision operator accumulate and swamp all other errors. We propose, and demonstrate, that the accumulation of this error can be avoided to a large extent by replacing the single collision operator with a set of operators with random errors and similar fidelities. Experiments have been implemented on 16 two-qubit sites for eight successive time steps for the Burgers equation.

  12. Experimental Identification of Diffusive Coupling Using 2D NMR

    NASA Astrophysics Data System (ADS)

    Song, Y.-Q.; Carneiro, G.; Schwartz, L. M.; Johnson, D. L.

    2014-12-01

    Spin relaxation based nuclear magnetic resonance (NMR) methods have been used extensively to determine pore size distributions in a variety of materials. This approach is based on the assumption that each pore is in the fast diffusion limit but that diffusion between pores can be neglected. However, in complex materials these assumptions may be violated and the relaxation time distribution is not easily interpreted. We present a 2D NMR technique and an associated data analysis that allow us to work directly with the time dependent experimental data without Laplace inversion to identify the signature of diffusive coupling between different pores. Measurements on microporous glass beads and numerical simulations are used to illustrate the technique.

  13. Semimetallic behavior in Fe2VAl: NMR evidence

    NASA Astrophysics Data System (ADS)

    Lue, Chin-Shan; Ross, Joseph H., Jr.

    1998-10-01

    We report the results of a 27Al and 51V nuclear magnetic resonance study of Fe2VAl at temperatures between 4 and 550 K. This material has been a subject of current interest due to indications of possible heavy fermion behavior. The low-temperature NMR relaxation rate follows a Korringa law, indicating a small density of carriers at the Fermi level. At elevated temperatures, the shifts and relaxation rates go over to a thermally activated response, a semiconductorlike behavior, consistent with separate low-lying bands removed from the Fermi-level. These results are consistent with recent electronic structure calculations, and can explain both the reported activated resistivity as well as the Fermi cutoff exhibited in photoemission studies. While we observe nonstoichiometric samples of (Fe1-xVx)3Al to be magnetic, the x=0.33 composition is nonmagnetic, with narrow NMR linewidths.

  14. Orbital ordering in UGa3: Detection by 69Ga NMR

    NASA Astrophysics Data System (ADS)

    Kambe, S.; Kato, H.; Sakai, H.; Walstedt, R. E.; Aoki, D.; Haga, Y.; Ônuki, Y.

    2002-12-01

    69Ga NMR spectra are reported and analyzed for the paramagnetic and antiferromagnetic (AFM) ordered states of UGa3(TN=67 K). Ordered-state splitting of the NMR lines indicates that the fourfold symmetry of the Ga-site hyperfine (HF) coupling is broken in the AFM state. A striking change in the Ga HF coupling constant also occurs at TN. These effects are attributed to uranium (5f) orbital ordering, which appears to set in just below TN. Orientation of the U moments has been determined as [11?](0

  15. An NMR study of hydrogen bonding in some azo dyestuffs

    NASA Astrophysics Data System (ADS)

    Wiench, J. W.; Schilf, W.; Stefaniak, L.; Webb, G. A.

    1999-11-01

    The 1H, 13C, and 15N NMR data reported for compounds 1- 4 show that in DMSO solutions all of them exist in the azo form only and do not participate in the azo-hydrazoimine equilibrium. The NMR data for compounds 1 and 2 show the presence of a weak hydrogen bond for the non-protonated forms, between N10 and the 2-N HCH 3 proton. All compounds have also been studied in TFA solutions in which they are protonated. The site of protonation of 1, 2 and 3 is determined to be at N10 in TFA solutions. These results are supported by some ab initio GIAO-CHF molecular orbital calculations.

  16. Auto-tuning for NMR probe using LabVIEW

    NASA Astrophysics Data System (ADS)

    Quen, Carmen; Pham, Stephanie; Bernal, Oscar

    2014-03-01

    Typical manual NMR-tuning method is not suitable for broadband spectra spanning several megahertz linewidths. Among the main problems encountered during manual tuning are pulse-power reproducibility, baselines, and transmission line reflections, to name a few. We present a design of an auto-tuning system using graphic programming language, LabVIEW, to minimize these problems. The program uses a simplified model of the NMR probe conditions near perfect tuning to mimic the tuning process and predict the position of the capacitor shafts needed to achieve the desirable impedance. The tuning capacitors of the probe are controlled by stepper motors through a LabVIEW/computer interface. Our program calculates the effective capacitance needed to tune the probe and provides controlling parameters to advance the motors in the right direction. The impedance reading of a network analyzer can be used to correct the model parameters in real time for feedback control.

  17. Structural analysis of teicoplanin A2 by 2d NMR

    NASA Astrophysics Data System (ADS)

    Heald, Sarah L.; Mueller, Luciano; Jeffs, Peter W.

    The analysis of the intact glycopeptide antibiotic, teicoplanin A 2, by two-dimensional proton NMR is described. Delayed-correlation spectroscopy (COSY), double-quantum coherence experiments (DACE), and nuclear Overhauser spectroscopy (NOESY) are utilized to confirm the primary structure. Distance constraints derived from NOESY data integrated with computer-assisted molecular modeling and force-field energy minimization yields a proposed three-dimensional solution-state conformation. Included are NMR methods developed for improved accuracy of distance measurements from 2D NOE experiments obtained on samples dissolved in DMSO- d6/water. The effects of different pulse sequences for water suppression on the 2D NOE spectral results are compared. Clear indication that teicoplanin exists in two unequally populated conformations which are in slow exchange is revealed by the presence of cross peaks attributable to conformational interchange in the NOESY spectra.

  18. NMR study of the solution structure of curcumin.

    PubMed

    Payton, Florastina; Sandusky, Peter; Alworth, William L

    2007-02-01

    Curcumin [1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione] is derived from the rhizomes of Curcuma longa. Although early studies concluded that curcumin exists predominantly as a keto-enol tautomer, 1b, in several recent articles the solution structure of curcumin has been represented as a beta-diketone tautomer, 1a. We have investigated the structure of curcumin in solvents ranging in polarity from CDCl3 to mixtures of DMSO-d6 in water, and in buffered aqueous DMSO-d6 solutions with pH values varying from 3 to 9. The solution structure of curcumin was determined on the basis of NMR techniques, including DEPT, HMQC, HMBC, and COSY. The results of the NMR studies show definitely that curcumin exists in solution as keto-enol tautomers, 1b. PMID:17315954

  19. Theoretical and experimental study of (15) N NMR protonation shifts.

    PubMed

    Semenov, Valentin A; Samultsev, Dmitry O; Krivdin, Leonid B

    2015-06-01

    A combined theoretical and experimental study revealed that the nature of the upfield (shielding) protonation effect in (15) N NMR originates in the change of the contribution of the sp(2) -hybridized nitrogen lone pair on protonation resulting in a marked shielding of nitrogen of about 100?ppm. On the contrary, for amine-type nitrogen, protonation of the nitrogen lone pair results in the deshielding protonation effect of about 25?ppm, so that the total deshielding protonation effect of about 10?ppm is due to the interplay of the contributions of adjacent natural bond orbitals. A versatile computational scheme for the calculation of (15) N NMR chemical shifts of protonated nitrogen species and their neutral precursors is proposed at the density functional theory level taking into account solvent effects within the supermolecule solvation model. Copyright © 2015 John Wiley & Sons, Ltd. PMID:25891386

  20. Low-frequency NMR with a non-resonant circuit.

    PubMed

    Hopper, Timothy; Mandal, Soumyajit; Cory, David; Hürlimann, Martin; Song, Yi-Qiao

    2011-05-01

    Nuclear magnetic resonance typically utilizes a tuned resonance circuit with impedance matching to transmit power and receive signal. The efficiency of such a tuned coil is often described in terms of the coil quality factor, Q. However, in field experiments such as in well-logging, the circuit Q can vary dramatically throughout the depth of the wellbore due to temperature or fluid salinity variations. Such variance can result in erroneous setting of NMR circuit parameters (tuning and matching) and subsequent errors in measurements. This paper investigates the use of a non-resonant transmitter to reduce the circuit sensitivity on Q and demonstrates that such circuits can be efficient in delivering power and current to the coil. We also describe a tuned receiver circuit whose resonant frequency can be controlled digitally. Experimental results show that a range of common NMR experiments can be performed with our circuits. PMID:21382732

  1. Low-frequency NMR with a non-resonant circuit

    NASA Astrophysics Data System (ADS)

    Hopper, Timothy; Mandal, Soumyajit; Cory, David; Hürlimann, Martin; Song, Yi-Qiao

    2011-05-01

    Nuclear magnetic resonance typically utilizes a tuned resonance circuit with impedance matching to transmit power and receive signal. The efficiency of such a tuned coil is often described in terms of the coil quality factor, Q. However, in field experiments such as in well-logging, the circuit Q can vary dramatically throughout the depth of the wellbore due to temperature or fluid salinity variations. Such variance can result in erroneous setting of NMR circuit parameters (tuning and matching) and subsequent errors in measurements. This paper investigates the use of a non-resonant transmitter to reduce the circuit sensitivity on Q and demonstrates that such circuits can be efficient in delivering power and current to the coil. We also describe a tuned receiver circuit whose resonant frequency can be controlled digitally. Experimental results show that a range of common NMR experiments can be performed with our circuits.

  2. NMR apparatus for in situ analysis of fuel cells

    DOEpatents

    Gerald, II, Rex E; Rathke, Jerome W

    2012-11-13

    The subject apparatus is a fuel cell toroid cavity detector for in situ analysis of samples through the use of nuclear magnetic resonance. The toroid cavity detector comprises a gas-tight housing forming a toroid cavity where the housing is exposed to an externally applied magnetic field B.sub.0 and contains fuel cell component samples to be analyzed. An NMR spectrometer is electrically coupled and applies a radiofrequency excitation signal pulse to the detector to produce a radiofrequency magnetic field B.sub.1 in the samples and in the toroid cavity. Embedded coils modulate the static external magnetic field to provide a means for spatial selection of the recorded NMR signals.

  3. Discovering [superscript 13]C NMR, [superscript 1]H NMR, and IR Spectroscopy in the General Chemistry Laboratory through a Sequence of Guided-Inquiry Exercises

    ERIC Educational Resources Information Center

    Iler, H. Darrell; Justice, David; Brauer, Shari; Landis, Amanda

    2012-01-01

    This sequence of three guided-inquiry labs is designed for a second-semester general chemistry course and challenges students to discover basic theoretical principles associated with [superscript 13]C NMR, [superscript 1]H NMR, and IR spectroscopy. Students learn to identify and explain basic concepts of magnetic resonance and vibrational…

  4. Why Are [superscript 1]H NMR Integrations Not Perfect? An Inquiry-Based Exercise for Exploring the Relationship between Spin Dynamics and NMR Integration in the Organic Laboratory

    ERIC Educational Resources Information Center

    Weizman, Haim

    2008-01-01

    When FT-NMR is used to collect data without a sufficient delay time between subsequent pulses, the integrated area under certain peaks may result in a lower value than should be observed under appropriate conditions. This discrepancy in integration may deceive the inexperienced eye and consequently can lead to a wrong assignment of the NMR

  5. NMR/MS Translator for the Enhanced Simultaneous Analysis of Metabolomics Mixtures by NMR Spectroscopy and Mass Spectrometry: Application to Human Urine.

    PubMed

    Bingol, Kerem; Brüschweiler, Rafael

    2015-06-01

    A novel metabolite identification strategy is presented for the combined NMR/MS analysis of complex metabolite mixtures. The approach first identifies metabolite candidates from 1D or 2D NMR spectra by NMR database query, which is followed by the determination of the masses (m/z) of their possible ions, adducts, fragments, and characteristic isotope distributions. The expected m/z ratios are then compared with the MS(1) spectrum for the direct assignment of those signals of the mass spectrum that contain information about the same metabolites as the NMR spectra. In this way, the mass spectrum can be assigned with very high confidence, and it provides at the same time validation of the NMR-derived metabolites. The method was first demonstrated on a model mixture, and it was then applied to human urine collected from a pool of healthy individuals. A number of metabolites could be detected that had not been reported previously, further extending the list of known urine metabolites. The new analysis approach, which is termed NMR/MS Translator, is fully automated and takes only a few seconds on a computer workstation. NMR/MS Translator synergistically uses the power of NMR and MS, enhancing the accuracy and efficiency of the identification of those metabolites compiled in databases. PMID:25881480

  6. 1D-NMR and 2D-NMR analysis of the thermal degradation products from vitrinites in relation to their

    E-print Network

    Boyer, Edmond

    is the most commonly used degradation method in the study of macromolecular materials due to the fact1D-NMR and 2D-NMR analysis of the thermal degradation products from vitrinites in relation the volatile and non-volatile fractions of the degradation products. From a study of selected perhydrous coals

  7. Synergistic effect of the simultaneous chemometric analysis of ¹H NMR spectroscopic and stable isotope (SNIF-NMR, ¹?O, ¹³C) data: application to wine analysis.

    PubMed

    Monakhova, Yulia B; Godelmann, Rolf; Hermann, Armin; Kuballa, Thomas; Cannet, Claire; Schäfer, Hartmut; Spraul, Manfred; Rutledge, Douglas N

    2014-06-23

    It is known that (1)H NMR spectroscopy represents a good tool for predicting the grape variety, the geographical origin, and the year of vintage of wine. In the present study we have shown that classification models can be improved when (1)H NMR profiles are fused with stable isotope (SNIF-NMR, (18)O, (13)C) data. Variable selection based on clustering of latent variables was performed on (1)H NMR data. Afterwards, the combined data of 718 wine samples from Germany were analyzed using linear discriminant analysis (LDA), partial least squares-discriminant analysis (PLS-DA), factorial discriminant analysis (FDA) and independent components analysis (ICA). Moreover, several specialized multiblock methods (common components and specific weights analysis (ComDim), consensus PCA and consensus PLS-DA) were applied to the data. The best improvement in comparison with (1)H NMR data was obtained for prediction of the geographical origin (up to 100% for the fused data, whereas stable isotope data resulted only in 60-70% correct prediction and (1)H NMR data alone in 82-89% respectively). Certain enhancement was obtained also for the year of vintage (from 88 to 97% for (1)H NMR to 99% for the fused data), whereas in case of grape varieties improved models were not obtained. The combination of (1)H NMR data with stable isotope data improves efficiency of classification models for geographical origin and vintage of wine and can be potentially used for other food products as well. PMID:24909771

  8. Can one and two-dimensional solid-state NMR fingerprint zeolite framework topology?

    PubMed

    Martineau, Charlotte; Vial, Sandrine; Barth, Dominique; Quessette, Franck; Taulelle, Francis

    2015-02-01

    In this contribution, we have explored the potential and strength of one-dimensional (1D) (29)Si and two-dimensional (2D) (29)S-(29)Si and (29)Si-(17)O NMR as invariants of non-oriented graph for fingerprinting zeolite frameworks. 1D and 2D (29)Si NMR can indeed provide indications on the graph vertices, edges and allow the construction of the adjacency matrix, i.e. the set of connections between the graph vertices. From the structural data, hypothetical 1D (29)Si and 2D (29)Si-(29)Si NMR signatures for 193 of the zeolite frameworks reported in the Atlas of Zeolite Structures have been generated. Comparison between all signatures shows that thanks to the 1D (29)Si NMR data only, almost 20% of the known zeolite frameworks could be distinguished. Further NMR signatures were generated by taking into account 2D (29)Si-(29)Si and (29)Si-(17)O correlations. By sorting and comparison of all the NMR data, up to 80% of the listed zeolites could be unambiguously discriminated. This work indicates that (i) solid-state NMR data indeed represent a rather strong graph invariant for zeolite framework, (ii) despite their difficulties and costs (isotopic labeling is often required, the NMR measurements can be long), (29)Si and (17)O NMR measurements are worth being investigated in the frame of zeolites structure resolution. This approach could also be generalized to other zeolite-related materials containing NMR-measurable nuclides. PMID:25454465

  9. High-resolution solid-state NMR of quadrupolar nuclei

    Microsoft Academic Search

    Eric Oldfield; Hye Kyung C. Timken; Ben Montez; R. Ramachandran

    1985-01-01

    Quadrupolar nuclei are the most abundant nuclear magnetic resonance (NMR)-receptive nuclei in the Earth's crust, and in many amorphous materials of technological interest (such as zeolite catalysts, ceramics and alloys), and have thus been intensively studied1-7. Of particular interest is the ability to resolve and quantitate the various types of sites present in a given material. Here we present a

  10. SIMPLTN, a Program for the Simulation of Pulse NMR Spectra

    Microsoft Academic Search

    Tim Allman; Alex D. Bain; Joel R. Garbow

    1996-01-01

    SIMPLTN, a computer program for thesimulation ofpulse andtwo-dimensionalNMR, is described and illustrated. The program is menu-driven and is designed to run as much like a spectrometer as possible. This approach allows a complete density-matrix calculation to be performed, yet still makes the program easy to use. SIMPLTN serves as a learning tool, and allows the design and testing of new

  11. NMR analysis, protonation equilibria and decomposition kinetics of tolperisone.

    PubMed

    Orgován, Gábor; Tihanyi, Károly; Noszál, Béla

    2009-12-01

    The rate constants of spontaneous and hydroxide-catalyzed decomposition and the tautomer-specific protonation constants of tolperisone, a classical muscle relaxant were determined. A solution NMR method without any separation techniques was elaborated to quantitate the progress of decomposition. All the rate and equilibrium constants were determined at four different temperatures and the activation parameters were calculated. The molecular mechanism of decomposition is proposed. PMID:19577875

  12. NMR study of 4-hydroxy-1-methylpiperidine betaine derivatives

    Microsoft Academic Search

    Z. Dega-Szafran; E. Dulewicz; M. Szafran

    2006-01-01

    Conformations of two 1-carbethoxymethyl-4-hydroxy-1-methylpiperidinium chlorides (1? and 1?), 4-hydroxy-1-methylpiperidine betaine hydrochlorides (2? and 2?), and 4-hydroxy-1-methylpiperidine betaine inner salts (3? and 3?), having a hydroxyl group at axial (?) or equatorial (?) positions, have been studied by the 1H and 13C NMR spectroscopy. The signals attributed to the equatorial and axial protons at C-2,6 have been found to differentiate the

  13. NMR Microscopy Using Large, Pulsed Magnetic-Field Gradients

    Microsoft Academic Search

    C. J. Rofe; J. Vannoort; P. J. Back; P. T. Callaghan

    1995-01-01

    The use of imaging schemes which employ large pulsed magnetic-field gradients to avoid susceptibility and diffusion artifacts in NMR microscopy is considered. The theory relating to these artifacts is briefly reviewed in the context of two specific pulse sequences, namely two-dimensional (i.e., slice-selective) phase-phase encoding and two-dimensional phase-frequency encoding in which the magnetization is recycled in a CPMG multi-pulse train.

  14. Characteristic NMR spectra of proton transfer in protonated water clusters

    NASA Astrophysics Data System (ADS)

    Lao-ngam, Charoensak; Phonyiem, Mayuree; Chaiwongwattana, Sermsiri; Kawazoe, Yoshiyuki; Sagarik, Kritsana

    2013-07-01

    Characteristic NMR spectra of proton transfer in protonated water clusters were studied using the H+(H2O)n complexes, n = 2 - 5, as model systems, and ab initio calculations at the RIMP2/TZVP level and BOMD simulations as model calculations. Based on the concept of presolvation, two-dimensional potential energy surface of proton in the smallest, most active intermediate complex (the Zundel complex) was constructed as a function of the H-bond distance (RO-O) and the asymmetric stretching coordinate (?dDA). The low-interaction energy path and the path with ?dDA = 0 Å were analyzed and discussed in comparison with the model systems. The two proton transfer paths associate with the characteristic IR frequencies namely, the structural diffusion and oscillatory shuttling frequencies, respectively. RIMP2/TZVP calculations showed that the proton moving on the oscillatory shuttling path is characterized by the 1H NMR shielding constant (?H+corr) varying in a narrow range, whereas on the structural diffusion path, ?H+corr changes exponentially with RO-H. The energetic, dynamic and spectroscopic results obtained from BOMD simulations in the temperature range between 350 and 450 K validated the presolvation model and revealed that the activation energies for the proton exchange in the smallest, most active intermediate complex, computed from the Arrhenius equation, IR spectra and a simple 1H NMR line shape analysis, are consistent and in good agreement with experiments in aqueous solution. Based on the presolvation model and the outstanding characteristics of the IR and 1H NMR spectra of the transferring protons, the present theoretical study suggested framework and steps to investigate structural diffusion processes in strong, protonated H-bond systems.

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

    Microsoft Academic Search

    Khan

    1986-01-01

    The proton NMR characteristics of internal pyroglutamic acid (Glp; 5-oxoproline) residues in seven tripeptides of the general structure Boc-Xxx-Glp-Yyy-NHâ were studied. In general, the chemical shifts of several diagnostic protons moved downfield on going from the Glu-containing peptides (Boc-Xxx-Glu-Yyy-NHâ) to the corresponding Glp-containing peptides. The C-2 proton of the Xxx residue was shifted by about 1.1 ppm. The N-2 proton

  16. Measuring protein reduction potentials using 15N HSQC NMR spectroscopy.

    PubMed

    Taylor, Samantha L; Crawley-Snowdon, Harriet; Wagstaff, Jane L; Rowe, Michelle L; Shepherd, Mark; Williamson, Richard A; Howard, Mark J

    2013-03-01

    NMR spectroscopy was used to measure reduction potentials of four redox proteins by following multiple (15)N HSQC protein resonances across a titration series using mixtures of oxidised and reduced glutathione. Results for PDI a, PDI ab and DsbA agree with the literature and our result for ERp18 confirms this protein as an oxidoreductase of comparable or greater reducing strength than PDI a. PMID:23360928

  17. Measuring protein reduction potentials using 15N HSQC NMR spectroscopy†

    PubMed Central

    Taylor, Samantha L.; Crawley-Snowdon, Harriet; Wagstaff, Jane L.; Rowe, Michelle L.; Shepherd, Mark; Williamson, Richard A.; Howard, Mark J.

    2015-01-01

    NMR spectroscopy was used to measure reduction potentials of four redox proteins by following multiple 15N HSQC protein resonances across a titration series using mixtures of oxidised and reduced glutathione. Results for PDI a, PDI ab and DsbA agree with the literature and our result for ERp18 confirms this protein as an oxidoreductase of comparable or greater reducing strength than PDI a. PMID:23360928

  18. Evolutionary and genetic optimization of NMR gradient and shim coils

    Microsoft Academic Search

    Jan Chládek; Pavel Konzbul; P. Osmera; A. Gottvald

    2000-01-01

    Evolutionary and genetic stochastic optimizations were explored for designing NMR gradient and shim coils. Together with their standard implementations, some hierarchical self-adaptible algorithms, based on a concept of meta-optimization, were tested. Time-demands and quality of the solutions were compared for various optimizers and a broad range of contrasting features was found for different settings of their governing parameters. Thus, an

  19. The Use of Dodecylphosphocholine Micelles in Solution NMR

    NASA Astrophysics Data System (ADS)

    Kallick, D. A.; Tessmer, M. R.; Watts, C. R.; Li, C. Y.

    Dodecylphosphocholine (DPC) micelles are useful as a model membrane system for solution NMR. Several new observations on dodecylphosphocholine micelles and their interactions with opioid peptides are described. The optimal lipid concentration has been investigated for small peptide NMR studies in DPC micelles for two opioid peptides, a 5-mer and a 17-mer. In contrast to reports in the literature, identical 2D spectra have been observed at low and high lipid concentrations. The chemical shift of resolved peptide proton resonances has been followed as a function of added lipid and indicates that there are changes in the chemical shifts above the critical micelle concentration and up to a ratio of 7:1 (lipid:peptide) for the 17-mer, and 9.6:1 for the 5-mer. These results suggest that conformational changes occur in the peptide significantly above the critical micelle concentration, up to a lipid:peptide ratio which is dependent upon the peptide, here ranging from 7:1 to 9.6:1. To address the stoichiometry more directly, the diffusion coefficients of the lipid alone and the lipid with peptide have been measured using pulsed-field gradient spin-echo NMR experiments. These data have been used to calculate the hydrodynamic radius and the aggregation number of the micelle with and without peptide and show that the aggregation number of the peptide-lipid complex increases at high lipid concentrations without a concomitant change in the peptide conformation. Last, several protonated impurities have been observed in the commercial preparation of DPC which resonate in the amide proton region of the NMR spectrum. These results are significant for researchers using DPC micelles and illustrate that both care in sample preparation and the stoichiometry are important issues with the use of DPC as a model membrane.

  20. Lipid?Ethanol Interaction Studied by NMR on Bicelles

    Microsoft Academic Search

    Bernd W. Koenig; Klaus Gawrisch

    2005-01-01

    The interaction of ethanol with phospholipids was studied in bicelles at a physiologically relevant ethanol concentration of 20 mM and a lipid content of 14 wt % by high-resolution NMR. Transient association of ethanol with magnetically aligned bicelles imparts a small degree of anisotropy to the solute. This anisotropy allows detection of residual 1H-1H and 1H-13C dipolar couplings, which are

  1. Quantitative 2H NMR spectroscopy with 1H lock extender.

    PubMed

    Vignali, Carlo; Caligiani, Augusta; Palla, Gerardo

    2007-07-01

    An inexpensive external unit that allows the use of the commercial high-resolution NMR spectrometer for (2)H observation with an (1)H lock system is described. The external unit does not require any tuning, is extremely easy to use, and could be a cheaper and more straightforward alternative to the more expensive (19)F lock configuration. An application for the quantitative determination of the natural isotopic ratio (2)H/(1)H of ethanol and acetic acid is reported. PMID:17485230

  2. NMR studies of selective population inversion and spin clustering

    SciTech Connect

    Baum, J.S.

    1986-02-01

    This work describes the development and application of selective excitation techniques in Nuclear Magnetic Resonance. Composite pulses and multiple-quantum methods are used to accomplish various goals, such as broadband and narrowband excitation in liquids, and collective excitation of groups of spins in solids. These methods are applied to a variety of problems, including non-invasive spatial localization, spin cluster size characterization in disordered solids and solid state NMR imaging.

  3. Beispiel und Übungen zur 1H-NMR Spektroskopie

    Microsoft Academic Search

    Reinhard Meusinger

    \\u000a In diesem Kapitel wird an Hand von vier Beispielen und sechs Übungen die Herangehensweise zur Auswertung von 1H-NMR Spektren demonstriert. Die Beispiele beinhalten den vollständigen und ausführlich erklärten Lösungsweg, währen es sich\\u000a bei den Übungen um Aufgabenblätter handelt, die zur selbständigen Arbeit dienen. Die vollständige Lösung wird aber direkt\\u000a im Anschluss gegeben, so dass man die eigenen Ergebnisse schnell überprüfen

  4. Relationship Between NMR Transverse Relaxation, Trabecular Bone Architecture, and Strength

    Microsoft Academic Search

    H. Chung; F. W. Wehrli; J. L. Williams; S. D. Kugelmass

    1993-01-01

    Structure, biomechanical competence, and incremental NMR line broadening (R'_2) of water in the intertrabecular spaces of cancellous bone were examined on 22 cylindrical specimens from the lumbar vertebral bodies of 16 human subjects 24-86 years old (mean, 60 years old). A strong association (r = 0.91; P < 0.0001) was found between Young's modulus of elasticity and R'_2 for a

  5. NMR-based metabonomics: a useful platform of oncology research

    Microsoft Academic Search

    Qian Shang; Jun-Feng Xiang; Ya-Lin Tang

    2010-01-01

    Cancer threatens human health, thus research focusing on oncology has great significance. Metabonomics is the global quantitative\\u000a assessment of the dynamic metabolic response of a biological system to some exogenous or genetic pathophysiological perturbation.\\u000a The metabolites are detected in tissues or fluids by various analytical methods, such as nuclear magnetic resonance (NMR)\\u000a and mass spectroscopy. Metabonomics, as a tool, can

  6. Spatial Modulation of the NMR Properties of the Cuprates

    NASA Astrophysics Data System (ADS)

    Haase, J.; Slichter, C. P.; Stern, R.; Milling, C. T.; Hinks, D. G.

    2000-11-01

    Substantial temperature dependent spatial modulation of the O and Cu NMR parameters of La 1.85Sr 0.15CuO 4 from 10 K to 300K are reported. The length scale of the modulations is only a few lattice distances. Analysis of the planar oxygen lineshape shows that modulations of the Knight shift and quadrupole coupling are correlated. The Cu spectra reveal a strong modulation of chemical shift. Similar results on other cuprates indicate universality of these phenomena.

  7. NMR study of the dissolution of laser-polarized xenon

    Microsoft Academic Search

    P. Berthault; H. Desvaux

    2003-01-01

    :   NMR of laser-polarized xenon is used to probe the dissolution behaviour of the noble gas in different liquids. The dissolution\\u000a and self-relaxation rates are extracted via a macroscopic model, and comparison of the decay rate of the xenon magnetization in deuterated and non-deuterated solvent\\u000a pairs allows the determination of the pure dipole-dipole contribution to relaxation. A transient convective effect,

  8. Inverse problem for in vivo NMR spatial localization

    SciTech Connect

    Hasenfeld, A.C.

    1985-11-01

    The basic physical problem of NMR spatial localization is considered. To study diseased sites, one must solve the problem of adequately localizing the NMR signal. We formulate this as an inverse problem. As the NMR Bloch equations determine the motion of nuclear spins in applied magnetic fields, a theoretical study is undertaken to answer the question of how to design magnetic field configurations to achieve these localized excited spin populations. Because of physical constraints in the production of the relevant radiofrequency fields, the problem factors into a temporal one and a spatial one. We formulate the temporal problem as a nonlinear transformation, called the Bloch Transform, from the rf input to the magnetization response. In trying to invert this transformation, both linear (for the Fourier Transform) and nonlinear (for the Bloch Transform) modes of radiofrequency excitation are constructed. The spatial problem is essentially a statics problem for the Maxwell equations of electromagnetism, as the wavelengths of the radiation considered are on the order of ten meters, and so propagation effects are negligible. In the general case, analytic solutions are unavailable, and so the methods of computer simulation are used to map the rf field spatial profiles. Numerical experiments are also performed to verify the theoretical analysis, and experimental confirmation of the theory is carried out on the 0.5 Tesla IBM/Oxford Imaging Spectrometer at the LBL NMR Medical Imaging Facility. While no explicit inverse is constructed to ''solve'' this problem, the combined theoretical/numerical analysis is validated experimentally, justifying the approximations made. 56 refs., 31 figs.

  9. NMR Studies of Molecules in Liquid Crystals and Graphite

    NASA Astrophysics Data System (ADS)

    Rosen, Mark Edward

    1992-01-01

    NMR has proven to be a rich source of information about molecular structure in condensed phases. A particularly good example of this is magnetic dipole couplings between protons on partially-oriented molecules. These couplings are very sensitive to the distance between the coupled protons and to the orientation of their internuclear vector with respect to the applied magnetic field. This spatial dependence gives proton dipole couplings the potential to be excellent probes of molecular conformation and orientation. This potential is usually not fully realized, since couplings between protons on molecules which undergo rapid conformational changes are averaged over all molecular motions which occur. The couplings, however, can provide detailed constraints on the time-averaged conformation of a molecule that can be used as a rigorous test of models for molecular interactions. NMR experiments to measure proton dipole couplings were performed on a series of n-alkanes (n-hexane through n-decane) dissolved in nematic liquid crystals. Computer modeling of the experimental NMR spectra was done using several different models for intermolecular interactions in these systems. The model of Photinos, et al. (1) was found to be best in describing the intermolecular interactions in these systems and can provide a statistical picture of the conformation and orientation of the alkane molecules in their partially-oriented environment. Order parameters and conformational distributions for the alkanes can be calculated from the modeling. The alkanes are found to have conformational distributions very much like those found in liquid alkanes. Proton NMR spectra of tetrahydrofuran (THF) intercalated in two graphite intercalation compounds were also measured. Computer simulations of these spectra provide a picture of THF in the constrained environment between the graphene layers where the THF is oriented at a particular angle, can translate and rotate freely, but does not appear to pseudorotate.

  10. Solution NMR of signal peptidase, a membrane protein.

    PubMed

    Musial-Siwek, Monika; Kendall, Debra A; Yeagle, Philip L

    2008-04-01

    Useful solution nuclear magnetic resonance (NMR) data can be obtained from full-length, enzymatically active type I signal peptidase (SPase I), an integral membrane protein, in detergent micelles. Signal peptidase has two transmembrane segments, a short cytoplasmic loop, and a 27-kD C-terminal catalytic domain. It is a critical component of protein transport systems, recognizing and cleaving amino-terminal signal peptides from preproteins during the final stage of their export. Its structure and interactions with the substrate are of considerable interest, but no three-dimensional structure of the whole protein has been reported. The structural analysis of intact membrane proteins has been challenging and only recently has significant progress been achieved using NMR to determine membrane protein structure. Here we employ NMR spectroscopy to study the structure of the full-length SPase I in dodecylphosphocholine detergent micelles. HSQC-TROSY spectra showed resonances corresponding to approximately 3/4 of the 324 residues in the protein. Some sequential assignments were obtained from the 3D HNCACB, 3D HNCA, and 3D HN(CO) TROSY spectra of uniformly 2H, 13C, 15N-labeled full-length SPase I. The assigned residues suggest that the observed spectrum is dominated by resonances arising from extramembraneous portions of the protein and that the transmembrane domain is largely absent from the spectra. Our work elucidates some of the challenges of solution NMR of large membrane proteins in detergent micelles as well as the future promise of these kinds of studies. PMID:18177734

  11. Multinuclear NMR approach to coal fly ash characterization

    SciTech Connect

    Netzel, D.A.

    1991-09-01

    This report describes the application of various nuclear magnetic resonance (NMR) techniques to study the hydration kinetics and mechanisms, the structural properties, and the adsorption characteristics of coal fly ash. Coal fly ash samples were obtained from the Dave Johnston and Laramie River electric power generating plants in Wyoming. Hydrogen NMR relaxation times were measured as a function of time to observe the kinetics of hydration for the two coal fly ashes at different temperatures and water-to-cement ration. The kinetic data for the hydrated coal fly ashes were compared to the hydration of portland cement. The mechanism used to describe the kinetic data for the hydration of portland cement was applied, with reservation, to describe the hydration of the coal fly ashes. The results showed that the coal fly ashes differ kinetically from that of portland cement and from each other. Consequently, both coal fly ashes were judged to be poorer cementitious materials than portland cement. Carbon-13 NMR CP/MAS spectra were obtained for the anhydrous coal fly ashes in an effort to determine the type of organic species that may be present, either adsorbed on the surface or entrained.

  12. Interfacing a microcomputer with the Varian EM-360 NMR spectrometer.

    PubMed

    Wright, J R

    1978-09-01

    Numerous NMR signal enhancement devices (CAT or Computers of Average Transients) are available commercially but at relatively high cost. These also have little or no flexibility of application, i.e., they are essentially signal averagers and nothing else. A far superior alternative, both in economy and range of application, is found in the new generation of computational devices based upon 8-bit LSI microprocessors. This paper reports the practical details of achieving a successful interface between one such microcomputer, the Altair 8800B, and the Varian EM-360 (1)H-NMR spectrometer. The resulting system is programmable in high level language (8k basic) and has sufficient memory to achieve 4096 point (12 bit) field resoltuion. The interface yields an intelligent instrument with multiple capabilities. Several operating modes have been developed using high level language programming, and these include conventional spectrum acquisition with variable field resolution, repetitive scan CAT, difference spectrometry, kinetic NMR spectrometry, progressive saturation analysis (for T1 and T2), and INDOR. The CAT program, for example, required 2 h to develop and debug, while a graphic output subroutine (shared by all modes) was written in 1 h. Correlation spectrometry is under development and requires user defined machine language routines. The system provides a graphic output of digitized data (using the existing recorder), magnetic storage of data files, and immediate data reduction capabilities. PMID:18699304

  13. Characterization of influenza hemagglutinin interactions with receptor by NMR.

    PubMed

    McCullough, Christopher; Wang, Minxiu; Rong, Lijun; Caffrey, Michael

    2012-01-01

    In influenza, the envelope protein hemagglutinin (HA) plays a critical role in viral entry by first binding to sialic acid receptors on the cell surface and subsequently mediating fusion of the viral and target membranes. In this work, the receptor binding properties of influenza A HA from different subtypes (H1 A/California/04/09, H5 A/Vietnam/1205/04, H5 A/bar-headed goose/Qinghai/1A/05, and H9 A/Hong Kong/1073/99) have been characterized by NMR spectroscopy. Using saturation transfer difference (STD) NMR, we find that all HAs bind to the receptor analogs 2,3-sialyllactose and 2,6-sialyllactose, with subtle differences in the binding mode. Using competition STD NMR, we determine the receptor preferences for the HA subtypes. We find that H5-Qinghai and H9-Hong Kong HA bind to both receptor analogs with similar affinity. On the other hand, H1 exhibits a clear preference for 2,6-sialyllactose while H5-Vietnam exhibits a clear preference for 2,3-sialyllactose. Together, these results are interpreted within the context of differences in both the amino acid sequence and structures of HA from the different subtypes in determining receptor preference. PMID:22815674

  14. Xe-129 NMR of xenon dissolved in biological media.

    NASA Astrophysics Data System (ADS)

    Mazitov, R. K.; Kuzma, N. N.; Happer, W.; Driehuys, B.; Merrill, G. F.

    2002-03-01

    The high solubility and large chemical shift of ^129Xe in various tissues makes it an ideal, non-invasive probe for pathological conditions such as cancer or atherosclerosis. To this end, we report NMR measurements of lineshapes, chemical shifts, and relaxation times of ^129Xe dissolved in the following biological tissues in vitro: heart, muscle, sinew, stomach(R.K. Mazitov, K. M. Enikeev, et al., Dokl. Akad. Nauk) 365, 396 (1999)., and the white and yolk of egg. NMR measurements of xenon dissolved in olive and sunflower oils are also reported. Tissues weighing 160--250 mg, not exposed to freezing, were studied in a 11.75 T field at the ^129Xe resonance frequency of 138.4 MHz; the pressure of xenon in the sealed-sample ampoules was ~20 bar. The influence of drugs and water content on tissues was studied. No xenon-water clathrates(J.A. Ripmeester and D.W. Davidson, J. Mol. Struct. ) 75, 67 (1981). were observed in the tissues, even at the high pressures used. The aim of this study is to establish possible correlations between the NMR parameters of dissolved xenon and the state of the tissue.

  15. Automated NMR relaxation dispersion data analysis using NESSY

    PubMed Central

    2011-01-01

    Background Proteins are dynamic molecules with motions ranging from picoseconds to longer than seconds. Many protein functions, however, appear to occur on the micro to millisecond timescale and therefore there has been intense research of the importance of these motions in catalysis and molecular interactions. Nuclear Magnetic Resonance (NMR) relaxation dispersion experiments are used to measure motion of discrete nuclei within the micro to millisecond timescale. Information about conformational/chemical exchange, populations of exchanging states and chemical shift differences are extracted from these experiments. To ensure these parameters are correctly extracted, accurate and careful analysis of these experiments is necessary. Results The software introduced in this article is designed for the automatic analysis of relaxation dispersion data and the extraction of the parameters mentioned above. It is written in Python for multi platform use and highest performance. Experimental data can be fitted to different models using the Levenberg-Marquardt minimization algorithm and different statistical tests can be used to select the best model. To demonstrate the functionality of this program, synthetic data as well as NMR data were analyzed. Analysis of these data including the generation of plots and color coded structures can be performed with minimal user intervention and using standard procedures that are included in the program. Conclusions NESSY is easy to use open source software to analyze NMR relaxation data. The robustness and standard procedures are demonstrated in this article. PMID:22032230

  16. Sensitivity enhancement of double quantum NMR spectroscopy by modified CPMG

    NASA Astrophysics Data System (ADS)

    Gowda, Chandrakala M.; Agarwal, Vipin; Kentgens, Arno P. M.

    2012-10-01

    A modified Carr-Purcell-Meiboom-Gill (CPMG) sequence for sensitivity enhancement of dipolar coupled homonuclear spin pairs in static solid-state NMR is presented. The modified CPMG block uses the Hahn-solid-Hahn echo as basic element of the CPMG echo train to refocus the homonuclear dipolar coupling and chemical shift anisotropy. The new CPMG sequence is dubbed as Hahn-solid-Hahn Carr-Purcell-Meiboom-Gill (HSHCPMG). We demonstrate a gain in signal to noise ratio of approximately 4.2 using HSHCPMG sequence in double quantum filtered CP experiment for 5%-13C2-15N-glycine. The resulting gain in sensitivity in the spikelet spectrum does not compromise the anisotropic information that is available from static NMR lineshapes. As an example, relative orientation angles of chemical shift anisotropy tensors for the alpha and carbonyl carbons in glycine are determined from the 2D DOQSY experiment recorded with the HSHCPMG block in the acquisition dimension. The resultant relative orientation angles of the two CSA tensors are compared to those obtained from 2D DOQSY experiment acquired without sensitivity enhancement as well as to the data as available from single crystal NMR experiments.

  17. Microcoils and microsamples in solid-state NMR.

    PubMed

    Takeda, Kazuyuki

    2012-01-01

    Recent reports on microcoils are reviewed. The first part of the review includes a discussion of how the geometries of the sample and coil affect the NMR signal intensity. In addition to derivation of the well-known result that the signal intensity increases as the coil size decreases, the prediction that dilution of a small sample with magnetically inert matter leads to better sensitivity if a tiny coil is not available is given. The second part of the review focuses on the issues specific to solid-state NMR. They include realization of magic-angle spinning (MAS) using a microcoil and harnessing of such strong pulses that are feasible only with a microcoil. Two strategies for microcoil MAS, the piggyback method and magic-angle coil spinning (MACS), are reviewed. In addition, MAS of flat, disk-shaped samples is discussed in the context of solid-state NMR of small-volume samples. Strong RF irradiation, which has been exploited in wide-line spectral excitation, multiple-quantum MAS (MQMAS), and dipolar decoupling experiments, has been accompanied by new challenges regarding the Bloch-Siegert effect, the minimum time resolution of the spectrometer, and the time scale of pulse transient effects. For a possible solution to the latter problem, recent reports on active compensation of pulse transients are described. PMID:23083521

  18. 2D NMR-spectroscopic screening reveals polyketides in ladybugs.

    PubMed

    Deyrup, Stephen T; Eckman, Laura E; McCarthy, Patrick H; Smedley, Scott R; Meinwald, Jerrold; Schroeder, Frank C

    2011-06-14

    Small molecules of biological origin continue to yield the most promising leads for drug design, but systematic approaches for exploring nature's cache of structural diversity are lacking. Here, we demonstrate the use of 2D NMR spectroscopy to screen a library of biorationally selected insect metabolite samples for partial structures indicating the presence of new chemical entities. This NMR-spectroscopic survey enabled detection of novel compounds in complex metabolite mixtures without prior fractionation or isolation. Our screen led to discovery and subsequent isolation of two families of tricyclic pyrones in Delphastus catalinae, a tiny ladybird beetle that is employed commercially as a biological pest control agent. The D. catalinae pyrones are based on 23-carbon polyketide chains forming 1,11-dioxo-2,6,10-trioxaanthracene and 4,8-dioxo-1,9,13-trioxaanthracene derivatives, representing ring systems not previously found in nature. This study highlights the utility of 2D NMR-spectroscopic screening for exploring nature's structure space and suggests that insect metabolomes remain vastly underexplored. PMID:21646540

  19. Stacking in RNA: NMR of Four Tetramers Benchmark Molecular Dynamics

    PubMed Central

    2015-01-01

    Molecular dynamics (MD) simulations for RNA tetramers r(AAAA), r(CAAU), r(GACC), and r(UUUU) are benchmarked against 1H–1H NOESY distances and 3J scalar couplings to test effects of RNA torsion parametrizations. Four different starting structures were used for r(AAAA), r(CAAU), and r(GACC), while five starting structures were used for r(UUUU). On the basis of X-ray structures, criteria are reported for quantifying stacking. The force fields, AMBER ff99, parmbsc0, parm99?_Yil, ff10, and parmTor, all predict experimentally unobserved stacks and intercalations, e.g., base 1 stacked between bases 3 and 4, and incorrect ?, ?, and sugar pucker populations. The intercalated structures are particularly stable, often lasting several microseconds. Parmbsc0, parm99?_Yil, and ff10 give similar agreement with NMR, but the best agreement is only 46%. Experimentally unobserved intercalations typically are associated with reduced solvent accessible surface area along with amino and hydroxyl hydrogen bonds to phosphate nonbridging oxygens. Results from an extensive set of MD simulations suggest that recent force field parametrizations improve predictions, but further improvements are necessary to provide reasonable agreement with NMR. In particular, intramolecular stacking and hydrogen bonding interactions may not be well balanced with the TIP3P water model. NMR data and the scoring method presented here provide rigorous benchmarks for future changes in force fields and MD methods. PMID:26082675

  20. NMR comparison of prokaryotic and eukaryotic cytochromes c.

    PubMed

    Chau, M H; Cai, M L; Timkovich, R

    1990-05-29

    1H NMR spectroscopy has been used to examine ferrocytochrome c-551 from Pseudomonas aeruginosa (ATCC 19429) over the pH range 3.5-10.6 and the temperature range 4-60 degrees C. Resonance assignments are proposed for main-chain and side-chain protons. Comparison of results for cytochrome c-551 to recently assigned spectra for horse cytochrome c (Wand et al. (1989) Biochemistry 28, 186-194) and mutants of yeast iso-1 cytochrome (Pielak et al. (1988) Eur. J. Biochem. 177, 167-177) reveals some unique resonances with unusual chemical shifts in all cytochromes that may serve as markers for the heme region. Results for cytochrome c-551 indicate that in the smaller prokaryotic cytochrome, all benzoid side chains are rapidly flipping on the NMR time scale. In contrast, in eukaryotic cytochromes there are some rings flipping slowly on the NMR time scale. The ferrocytochrome c-551 undergoes a transition linked to pH with a pK around 7. The pH behavior of assigned resonances provides evidence that the site of protonation is the inner or buried 17-propionic acid heme substituent (IUPAC-IUB porphyrin nomenclature). Conformational heterogeneity has been observed for segments near the inner heme propionate substituent. PMID:2165802