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Sample records for lanthanide-induced phosphorus-31 nmr

  1. Phosphorus solubility of agricultural soils: a surface charge and phosphorus-31 NMR speciation study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We investigated ten soils from six states in United States to determine the relationship between potentiometric titration derived soil surface charge and Phosphorus-31 (P) nuclear magnetic resonance (NMR) speciation with the concentration of water-extractable P (WEP). The surface charge value at the...

  2. 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…

  3. Phosphorus-31 NMR visibility and characterization of rat liver mitochondrial matrix adenine nucleotides

    SciTech Connect

    Hutson, S.M.; Berkich, D.; Williams, G.D.; LaNoue, K.F.; Briggs, R.W. )

    1989-05-16

    Compartmentation and NMR visibility of mitochondrial adenine nucleotides were quantitated in isolated rat liver mitochondria respiring on succinate and glutamate in vitro at 8 and 25{degree}C. Intra- and extramitochondrial nucleotides were discriminated by adding the chelator trans-1,2-diaminocyclohexane-N,N,N{prime},N{prime}-tetraacetic acid (CDTA). T{sub 1} values of about 0.2-0.3 s for magnesium-bound matrix nucleotides were determined. Adenine nucleotide T{sub 1} values were influenced by the ionic environment; only magnesium-free ATP T{sub 1}'s were affected by temperature. Intra- and extramitochondrial adenine nucleotide ratios were varied in ATP-loaded mitochondria with added ATP and phosphate using the mitochondrial inhibitors oligomycin and carboxyatractyloside, and adenine nucleotides were quantitated by using NMR and enzymatic analysis. There was good agreement between matrix ATP concentrations (magnesium-bound ATP) calculated by using NMR and standard biochemical techniques. Although matrix ADP could be detected by NMR, it was difficult to quantitate accurately by NMR. The data indicate that mitochondrial ATP is NMR-visible in isolated mitochondria in vitro.

  4. A high-resolution phosphorus-31 nuclear magnetic resonance (NMR) spectroscopic method for the non-phosphorus markers of chemical warfare agents.

    PubMed

    Mazumder, Avik; Kumar, Ajeet; Purohit, Ajay K; Dubey, Devendra K

    2012-02-01

    A high-resolution phosphorus-31 nuclear magnetic resonance (NMR) spectroscopic method has been developed for detection, identification and quantification of non-phosphorus markers of toxic nerve agents (soman and V-class), vesicants (HD, HN-2, HN-3), and incapacitating agent (Bz). These analytes were converted to phosphorus-containing derivatives via phosphitylation reaction of their hydroxyl and sulfhydryl functions (using 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane). This was followed by (31)P{(1)H} and (31)P NMR analysis of these derivatives. The chemical shifts (δ) and coupling constants ((3)J(P-H)) of derivatives were used for their specific detection and identification. The method allowed clear distinction between the alcohols and thiols. The lower limits of detection of these analytes were found to be between 12 and 28 μg obtained from 128 transients of (31)P{(1)H} quantitative NMR experiments. Utility of the method was ensured by the detection and identification of triethanolamine present (at an original concentration of 5 μg/mL) in an aqueous sample from 28th OPCW Official Proficiency Tests. PMID:22160203

  5. 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.

  6. Alk-1-enylacyl, alkylacyl, and diacyl subclasses of native ethanolamine and choline glycerophospholipids can be quantified directly by phosphorus-31 NMR in solution.

    PubMed

    Malewicz, B; Baumann, W J

    1996-11-01

    We show that phosphorus-31 nuclear magnetic resonance spectroscopy can be used to distinguish and to quantify the alk-1-enylacyl, alkylacyl, and diacyl glycerophosphoethanolamine (GPE) subclasses, and the respective glycerophosphocholine (GPC) subclasses, in their native form without prior degradation or derivatization, provided the phospholipids are observed in the nonaggregated state. Monomeric phospholipid distribution is ascertained by recording the spectra, after removal of metal ions, on CDCl3/CD3OD/D2O (50:50:15, by vol) solutions. The utility of this approach is exemplified for the ethanolamine glycerophospholipids (EPL) from bovine brain and the choline glycerophospholipids (CPL) from bovine heart. Sharp and well-resolved resonances are obtained for alkylacylGPE (+0.395 ppm; re 1% H3PO4), alkenylacylGPE (+0.353 ppm), and diacylGPE (+0.315 ppm), and for alkylacylGPC (-0.383 ppm), alkenyl-acylGPC (-0.436 ppm) and diacylGPC (-0.451 ppm). Integrated peak areas are shown to closely correlate with dose. Accurate quantitation of EPL and CPL subclasses at submicromolar levels can further be facilitated by use of synthetic dialkylGPE (+0.602 ppm) and dialkylGPC (-0.196 ppm) as internal standards. The method is simple, rapid, sensitive and reproducible, and permits the complete resolution and direct quantitation of all ethanolamine and choline glycerophospholipid subclasses quite independent of fatty chain length and degree of unsaturation. PMID:8934452

  7. 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.

  8. Phosphorus-31 NMR spectra of ethidium, quinacrine, and daunomycin complexes with poly(adenylic acid)ter dot poly(uridylic acid) RNA duplex and calf thymus DNA

    SciTech Connect

    Gorenstein, D.G.; Lai, K. )

    1989-04-04

    {sup 31}P NMR provides a convenient monitor of the phosphate ester backbone conformational changes upon binding of the intercalating drugs ethidium, quinacrine, and daunomycin to sonicated poly(A){center dot}poly(U) and calf thymus DNA. {sup 31}P chemical shifts can also be used to assess differences in the duplex unwinding angles in the presence of the drug. Thus a new {sup 31}P signal, 1.8-2.2 ppm downfield from the double-stranded helix signals, is observed in the ethidium ion-poly(A){center dot}poly(U) complex. This signal arises from phosphates which are in perturbed environments due to intercalation of the drug. This is in keeping with the hypothesis that the P-O ester torsional angle in phosphates linking the intercalated base pairs is more trans-like. Similar though smaller deshielding of the {sup 31}P signals is observed in sonicated poly(A){center dot}poly(U)-quinacrine complexes as well as in the daunomycin complexes. The effect of added ethidium ion, quinacrine, and daunomycin on the {sup 31}P spectra of sonicated calf thymus DNA is consistent with Wilson and Jones' (1982) earlier study. In these drug-DNA complexes the drug produces a gradual downfield shift in the DNA {sup 31}P signal without the appearance of a separate downfield peak. These differences are attributed to differences in the rate of chemical exchange of the drug between free and bound duplex states. The previous correlation of {sup 31}P chemical shift with drug duplex unwinding angle is confirmed for both the RNA and DNA duplexes.

  9. 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. )

    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.

  10. Phosphorus 31 nuclear magnetic resonance examination of female reproductive tissues

    SciTech Connect

    Noyszewski, E.A.; Raman, J.; Trupin, S.R.; McFarlin, B.L.; Dawson, M.J. )

    1989-08-01

    Nuclear magnetic resonance spectroscopy is a powerful method of investigating the relationship between metabolism and function in living tissues. We present evidence that the phosphorus 31 spectra of myometrium and placenta are functions of physiologic state and gestational age. Specific spectroscopic abnormalities are observed in association with disorders of pregnancy and gynecologic diseases. Our results suggest that noninvasive nuclear magnetic resonance spectroscopy examinations may sometimes be a useful addition to magnetic resonance imaging examinations, and that nuclear magnetic resonance spectroscopy of biopsy specimens could become a cost-effective method of evaluating certain biochemical abnormalities.

  11. The solution structure of Ln (DOTP) 5- complexxes. A comparison of lanthanide-induced paramagnetic shifts with the MMX energy-minimized structure

    NASA Astrophysics Data System (ADS)

    Geraldes, Carlos F. G. C.; Sherry, A. Dean; Kiefer, Garry E.

    Complexes between the trivalent lanthanide ions and the macrocyclic chelate 1,4,7,10-tetraazacyclododecane- N,N',N″,N‴-tetra(methylene phosphonate) (DOTP) have been examined by high-resolution NMR spectroscopy. The proton spectra of the diamagnetic La(DOTP) 5- and Lu(DOTP) 5- complexes provide evidence for very rigid chelate structures with the ethylenediamine-containing chelate rings essentially locked into a single conformation at room temperature. The activation energy for ethylenediamine chelate ring interconversions in these complexes is approximately 100 kJ mol -1, considerably higher than that reported previously for the corresponding Ln(DOTA) - complexes (DOTA is the tetraacetate analog of DOTP). Lanthanide-induced shifts are reported for all 1H, 13C, and 31P nuclei in 11 Ln(DOTP) 5- complexes. The proton spectra of these complexes display unusually large lanthanide-induced shifts, one showing a spectrum in which the 1H resonances span 900 ppm. The contact and pseudocontact contributions to these shifts were separated using Reilley's temperature-independent method and the resulting pseudocontact lanthanide-induced NMR shifts were in excellent agreement with those calculated for a structure derived using MMX molecular modeling methods. The pseudocontact shifts provide evidence for Ln (DOTP) 5- chelates which have virtually identical structures along the lanthanide series, with the possible exception of Tm(DOTP) 5-.

  12. Phosphatic metabolites of the intact cornea by phosphorus-31 nuclear magnetic resonance.

    PubMed

    Greiner, J V; Kopp, S J; Gillette, T E; Glonek, T

    1983-05-01

    The principal low molecular weight phosphatic metabolites of the intact cornea were identified and quantitated nondestructively by phosphorus-31 nuclear magnetic resonance (P-31 NMR) spectroscopy. As part of this analytical procedure, the intracorneal pH was approximated from the resonance shift position of inorganic orthophosphate. In addition the metabolic and pH stability of incubated corneas at 37 C in MK medium was evaluated during an 8-hr time course and compared to similar dynamic analyses performed on corneas with denuded endothelium. Perchloric acid extracts prepared from these same corneas were analyzed by P-31 NMR to verify the metabolite peak assignments and to quantitate the concentrations of minor corneal metabolites. The concentrations of phosphatic metabolites of the cornea, including three previously unidentified phosphorus-containing substances, were determined for freshly excised corneas. The initial corneal spectroscopic profile was not altered by removal of the endothelium. At 37 C the MK media-incubated intact whole corneas experienced a time-dependent decline in ATP levels with a concomitant rise in inorganic orthophosphate; however, the tissue levels of the other principal phosphatic metabolites were not altered by prolonged incubation. In contrast, removal of the endothelial layer of the cornea-induced progressive metabolic deterioration of intact corneas characterized, most prominantly, by time-dependent declines in ATP and glycerol 3-phosphorylcholine levels and concomitant increases in ADP and inorganic orthophosphate levels relative to intact whole corneas. This study has established the feasibility of monitoring the metabolic status of intact rabbit corneas nondestructively and noninvasively. As such, P-31 NMR spectroscopy offers a promising method that may enable analysis of the metabolic viability of intact human donor corneas to provide a basis for selecting donor corneas for transplantation. PMID:6840999

  13. 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.

  14. A sex-specific metabolite identified in a marine invertebrate utilizing phosphorus-31 nuclear magnetic resonance.

    PubMed

    Kleps, Robert A; Myers, Terrell C; Lipcius, Romuald N; Henderson, Thomas O

    2007-01-01

    Hormone level differences are generally accepted as the primary cause for sexual dimorphism in animal and human development. Levels of low molecular weight metabolites also differ between men and women in circulating amino acids, lipids and carbohydrates and within brain tissue. While investigating the metabolism of blue crab tissues using Phosphorus-31 Nuclear Magnetic Resonance, we discovered that only the male blue crab (Callinectes sapidus) contained a phosphorus compound with a chemical shift well separated from the expected phosphate compounds. Spectra obtained from male gills were readily differentiated from female gill spectra. Analysis from six years of data from male and female crabs documented that the sex-specificity of this metabolite was normal for this species. Microscopic analysis of male and female gills found no differences in their gill anatomy or the presence of parasites or bacteria that might produce this phosphorus compound. Analysis of a rare gynandromorph blue crab (laterally, half male and half female) proved that this sex-specificity was an intrinsic biochemical process and was not caused by any variations in the diet or habitat of male versus female crabs. The existence of a sex-specific metabolite is a previously unrecognized, but potentially significant biochemical phenomenon. An entire enzyme system has been synthesized and activated only in one sex. Unless blue crabs are a unique species, sex-specific metabolites are likely to be present in other animals. Would the presence or absence of a sex-specific metabolite affect an animal's development, anatomy and biochemistry? PMID:17712428

  15. One-dimensional phosphorus-31 chemical shift imaging of human brain tumors

    SciTech Connect

    Rutter, A.; Hugenholtz, H.; Saunders, J.K.

    1995-06-01

    Phosphorus magnetic resonance spectroscopy has been used noninvasively to determine characteristic spectral parameters for untreated human brain tumors as a prelude to its use in clinical diagnosis. The spectra, which reflect the relative amounts of phosphorus-containing compounds, and the pH within and surrounding the tumors, were obtained in vivo using the the localization technique of one-dimensional chemical shift imaging applied with a surface coil. Phosphorus-31 chemical shift imaging was performed successfully in vivo on 9 volunteers and 27 patients with untreated brain tumors, including 7 with astrocytoma, 4 with glioblastoma, 3 with meningioma, and 11 with metastases. This study provides spectra from within and surrounding the brain tumors, and allows accountability for the heterogeneity of brain tumors by the selection of the maximum data point for each parameter. The ratios of resonance areas, phosphodiesters over nucleoside triphosphate (NTP), and phosphomonoesters over NTP, were found to be higher in glioblastomas (2.55 {plus_minus} 0.22, 1.06 {plus_minus} 0.09) and astorcytomas (3.04 {plus_minus} 0.36, 1.28 {plus_minus} 0.36) than in normal brain (2.00 {plus_minus} 0.32, 0.79 {plus_minus}0.22). The ratios of areas due to inorganic phosphate and NTP, and phosphocreatine and NTP, also were higher in astrocytomas (1.16 {plus_minus} 0.40, 1.17 {plus_minus} 0.41) compared with glioblastomas (0.68 {plus_minus} 0.01, 0.88 {plus_minus} 0.19) and normal brain (0.61 {plus_minus}0.03, 0.77 {plus_minus} 0.03). The pH of brain tumors ranged from alkaline to neutral, with meningiomas consistently having alkaline pH. These data show that there are statistically significant differences in the magnetic resonance parameters of the affected brain hemispheres of patients with astrocytomas, glioblastomas, meningiomas, and normal brain tissue, and underline the need for a multisite clinical trial to establish clinical criteria for diagnosis. 28 refs., 3 figs., 2 tabs.

  16. 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.

  17. Phosphorus-31 MRI of bones using quadratic echo line-narrowing

    NASA Astrophysics Data System (ADS)

    Frey, Merideth; Barrett, Sean; Insogna, Karl; Vanhouten, Joshua

    2012-02-01

    There is a great need to probe the internal composition of bone on the sub-0.1 mm length scale, both to study normal features and to look for signs of disease. Despite the obvious importance of the mineral fraction to the biomechanical properties of skeletal tissue, few non-destructive techniques are available to evaluate changes in its chemical structure and functional microarchitecture on the interior of bones. MRI would be an excellent candidate, but bone is a particularly challenging tissue to study given the relatively low water density and wider linewidths of its solid components. Recent fundamental research in quantum computing gave rise to a new NMR pulse sequence - the quadratic echo - that can be used to narrow the broad NMR spectrum of solids. This offers a new route to do high spatial resolution, 3D ^31P MRI of bone that complements conventional MRI and x-ray based techniques to study bone physiology and structure. We have used our pulse sequence to do 3D ^31P MRI of ex vivo bones with a spatial resolution of (sub-450 μm)^3, limited only by the specifications of a conventional 4 Tesla liquid-state MRI system. We will describe our plans to push this technique towards the factor of 1000 increase in spatial resolution imposed by fundamental limits.

  18. Transport and phosphorylation of choline in higher plant cells. Phosphorus-31 nuclear magnetic resonance studies

    SciTech Connect

    Bligny, R.; Foray, M.F.; Roby, C.; Douce, R.

    1989-03-25

    When sycamore cells were suspended in basal medium containing choline, the latter was taken up by the cells very rapidly. A facilitated diffusion system appertained at low concentrations of choline and exhibited Michaelis-Menten kinetics. At higher choline concentrations simple diffusion appeared to be the principal mode of uptake. Addition of choline to the perfusate of compressed sycamore cells monitored by /sup 31/P NMR spectroscopy resulted in a dramatic accumulation of P-choline in the cytoplasmic compartment containing choline kinase and not in the vacuole. The total accumulation of P-choline over a 10-h period exhibited Michaelis-Menten kinetics. During this period, in the absence of Pi in the perfusion medium there was a marked depletion of glucose-6-P, and the cytoplasmic Pi resonance disappeared almost completely. When a threshold of cytoplasmic Pi was attained, the phosphorylation of choline was sustained by the continuous release of Pi from the vacuole although at a much lower rate. However, when 100 microM inorganic phosphate was present in the perfusion medium, externally added Pi was preferentially used to sustain P-choline synthesis. It is clear, therefore, that cytosolic choline kinase associated with a carrier-mediated transport system for choline uptake appeared as effective systems for continuously trapping cytoplasmic Pi including vacuolar Pi entering the cytoplasm.

  19. Phosphorus-31 nuclear magnetic resonance spectroscopy transect study of poultry operations on the Delmarva Peninsula.

    PubMed

    Hill, Jane E; Cade-Menun, Barbara J

    2009-01-01

    Nonpoint source phosphorus (P) pollution into the Chesapeake Bay watershed from poultry operations contributes to the algal blooms, hypoxia, anoxia, and fish kill events that occur there most years. A major source of soluble, bioavailable P species is poultry litter, which is used as a crop fertilizer on fields adjacent to the tributaries of the Bay. A potentially significant source of orthophosphate in the litter is the heavily phosphorylated compound myo-inositol hexakisphosphate (phytate), which is indigestible by poultry and thus becomes a major component of their excreta. Phytate evaluation in environmental samples is expensive; hence, its impact is not captured in standard farmer-friendly eutrophication potential guides, like Delaware's Phosphorus Site Index. In this transect study of two poultry operations on the Delmarva Peninsula, we measured the incidence of all P compounds using solution 31P nuclear magnetic resonance (NMR) spectroscopy and extracts, relating them to relevant geochemical properties. The contribution of phytate to the overall pool of P declined from around 50% in manures to between 2 and 13% in down-gradient soils and sediments, corresponding to a rise in the relative proportion of orthophosphate (increasing from 39% to 65-88%). The results show that the large pool of phytate P spread onto croplands during standard operating practice at poultry farms on the Delmarva Peninsula does not appear to accumulate; rather, phytate decreases in down-gradient locations, most likely due to transport off-site and/or through in situ biological activity. PMID:19141802

  20. Phosphorus-31 nuclear magnetic resonance study of post mortem catabolism and intracellular pH in intact excised rabbit muscle.

    PubMed

    Renou, J P; Canioni, P; Gatelier, P; Valin, C; Cozzone, P J

    1986-04-01

    Phosphorus-31 nuclear magnetic resonance has been used to study the post mortem catabolism of high-energy phosphate compounds and the associated intracellular pH variation in pure fast- and slow-twitch rabbit muscles and in rabbit muscle with mixed fiber types. Comparative results from pure fiber types are reported for the first time. Large amounts of glycerophosphorylcholine (14.1 mumol/g fresh tissue) are found in the internal conoidal bundle (ICB), a pure oxidative slow twitch muscle, whereas the m. psoas major (PM), a pure glycolytic fast twitch muscle and the m. gastrocnemius caput medialis (GCM), with mixed fiber types, are devoid of the same metabolite. The total content of phosphorylated metabolites is constant among the three muscle types. The time-dependent post mortem changes in phosphorylated metabolites display the expected rapid drop in phosphocreatine and a simultaneous increase in intracellular inorganic phosphate. However, the ATP level remains constant during more than 2 h. Rate constants for metabolite breakdown and apparent ATPase activity have been determined. The comparative kinetics of intracellular acidosis at 25 degrees C yield rates of 3.3 X 10(-3) pH unit/min for PM, 2.7 X 10(-3) pH unit/min for GCM and 3.0 X 10(-3) pH unit/min for ICB. Initial intracellular pH values are 7.07, 7.20 and 7.02, respectively. Upon aging, the heterogeneity of the Pi signal reflects the existence of cellular compartments with different internal pH. The results suggest that the more intense low-pH Pi signal arises from the sarcoplasmic reticulum while the less intense resonance would reflect the sarcoplasmic higher pH. The temperature effect on post mortem catabolism in the 15-25 degrees C range has been documented. As expected, phosphocreatine and ATP breakdown increase with temperature but at a higher rate for slow-twitch ICB than for fast-twitch PM. PMID:3091088

  1. MR imaging and spectroscopy of the basal ganglia in chronic liver disease: correlation of T1-weighted contrast measurements with abnormalities in proton and phosphorus-31 MR spectra.

    PubMed

    Taylor-Robinson, S D; Sargentoni, J; Oatridge, A; Bryant, D J; Hajnal, J V; Marcus, C D; Seery, J P; Hodgson, H J; deSouza, N M

    1996-09-01

    The purpose of this study was to correlate the hyperintensity in the globus pallidus seen on T1-weighted magnetic resonance imaging (MRI) of the brain in chronic liver disease with changes in metabolite ratios measured from both proton and phosphorus-31 magnetic resonance spectroscopy (MRS) localised to the basal ganglia. T1-weighted spin echo (T1WSE) images were obtained in 21 patients with biopsy-proven cirrhosis (nine Child's grade A, eight Child's grade B and four Child's grade C). Four subjects showed no evidence of neuropsychiatric impairment on clinical, psychometric and electrophysiological testing, four showed evidence of subclinical hepatic encephalopathy and 13 had overt hepatic encephalopathy. Signal intensities of the globus pallidus and adjacent brain parenchyma were measured and contrast calculated, which correlated with the severity of the underlying liver disease, when graded according to the Pugh's score (p < 0.05). Proton MRS of the basal ganglia was performed in 12 patients and 14 healthy volunteers. Peak area ratios of choline (Cho), glutamine and glutamate (Glx) and N-acetylaspartate relative to creatine (Cr) were measured. Significant reductions in mean Cho/Cr and elevations in mean Glx/Cr ratios were observed in the patient population. Phosphorus-31 MRS of the basal ganglia was performed in the remaining nine patients and in 15 healthy volunteers. Peak area ratios of phosphomonoesters (PME), inorganic phosphate, phosphodiesters (PDE) and phosphocreatine relative to beta ATP (ATP) were then measured. Mean values of PME/ATP and PDE/ATP were significantly lower in the patient population. No correlation was found between the T1WSE MRI contrast measurements of the globus pallidus and the abnormalities in the metabolite ratios measured from either proton or phosphorus-31 MR spectra. Our results suggest that pallidal hyperintensity seen on T1WSE MR imaging of patients with chronic liver disease is not related to the functional abnormalities of the

  2. 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

  3. Absolute concentration determination of phosphorus metabolites in the Langendorff-perfused rabbit heart by phosphorus-31 nuclear magnetic resonance

    SciTech Connect

    Gard, J.K.

    1984-01-01

    The concentrations of mobile high energy phosphorus metabolites and intracellular pH of Langendorff-perfused rabbit heart have been determined under control and reduced flow conditions. Absolute concentration determination was accomplished by Lorentzian lineshape analysis after development of hexachlorocyclotriphosphazene as an external intensity standard. Hearts were demonstrated to be biochemically and physiologically competent during control perfusion periods and compromised during reduced flow conditions by independent hemodynamic and metabolic measurements coincident with the NMR experiment. Reduction in perfusate flow from 20 mL/min to 5.0 mL/min (25% flow) or 2.5 mL/min (12.5% flow) demonstrated a fall in phosphocreatine and adenosine triphosphate concentrations, a rise in cytosolic inorganic phosphate concentrations, and drops in pH. Subsequent recovery upon reflow was observed. The derived values for the free concentration of ADP were very close to the reported values of the Michaelis constant for respiratory stimulation, implicating a regulatory role for this molecule in cellular respiration. Strong evidence that the creating kinase reaction was in equilibrium in the 25% flow study was seen. The NMR observable correlated closely with myocardial performance and biochemical indices of metabolic function, and supported the use of phosphocreatine as an indicator of current metabolic integrity.

  4. Comparison of Crystal Field Dependent and Independent Methods to Analyse Lanthanide Induced NMR Shifts in Axially Symmetric Complexes. Part II: Systems with a C4 Symmetry Axis

    PubMed Central

    Zhang, Shanrong; Sherry, A. Dean

    2003-01-01

    Analysis of the LIS data for several series of Ln3+ complexes of C4 symmetry in terms of structural changes, crystal-field effects and/or variation of hyperfine constants along the lanthanide series was undertaken using a combination of the two-nuclei and three-nuclei techniques together with the classical onenucleus technique. Isostructurality of whole series of complexes, with changes of the Fi, and B02 parameters, was clearly defined for the complexes of L by the combination of the two first methods. Small changes, involving the three Fi, Gi and B02 parameters, are observed for the series of complexes of L-L4, using the three data plotting methods. Some of the plots according to the two- and three-nuclei methods are accidentally linear, without necessarily implying isostructurality of the complexes, as they involve parameters, which may be insensitive to any small structural changes occurring in these systems. These parameter variations could result from a magnification, by the present graphical analysis, of the breaks expected from the gradual structural changes along the series due to the lanthanide contraction. The α and β parameters of the three-nuclei method are not diagnostic of the type of structures the complexes have in solution, due to their very indirect dependence on the geometric factors. PMID:18365039

  5. Protective effect of pretreatment with the calcium antagonist anipamil on the ischemic-reperfused rat myocardium: a phosphorus-31 nuclear magnetic resonance study

    SciTech Connect

    Kirkels, J.H.; Ruigrok, T.J.; Van Echteld, C.J.; Meijler, F.L.

    1988-05-01

    To assess whether the prophylactic administration of anipamil, a new calcium antagonist, protects the heart against the effects of ischemia and reperfusion, rats were injected intraperitoneally twice daily for 5 days with 5 mg/kg body weight of this drug. The heart was then isolated and perfused by the Langendorff technique. Phosphorus-31 nuclear magnetic resonance spectroscopy was used to monitor myocardial energy metabolism and intracellular pH during control perfusion and 30 min of total ischemia (37/sup 0/C), followed by 30 min of reperfusion. Pretreatment with anipamil altered neither left ventricular developed pressure under normoxic conditions nor the rate and extent of depletion of adenosine triphosphate (ATP) and creatine phosphate during ischemia. Intracellular acidification, however, was attenuated. On reperfusion, hearts from anipamil-pretreated animals recovered significantly better than untreated hearts with respect to replenishment of ATP and creatine phosphate stores, restitution of low levels of intracellular inorganic phosphate and recovery of left ventricular function and coronary flow. Intracellular pH recovered rapidly to preischemic levels, whereas in untreated hearts a complex intracellular inorganic phosphate peak indicated the existence of areas of different pH within the myocardium. It is concluded that anipamil pretreatment protects the heart against some of the deleterious effects of ischemia and reperfusion. Because this protection occurred in the absence of a negative inotropic effect during normoxia, it cannot be attributed to an energy-sparing effect during ischemia. Therefore, alternative mechanisms of action are to be considered.

  6. Creatine target engagement with brain bioenergetics: a dose-ranging phosphorus-31 magnetic resonance spectroscopy study of adolescent females with SSRI-resistant depression

    PubMed Central

    Kondo, Douglas G.; Forrest, Lauren N.; Shi, Xianfeng; Sung, Young-Hoon; Hellem, Tracy L.; Huber, Rebekah S.; Renshaw, Perry F.

    2016-01-01

    Major depressive disorder (MDD) often begins during adolescence and is projected to become the leading cause of global disease burden by the year 2030. Yet, approximately 40 % of depressed adolescents fail to respond to standard antidepressant treatment with a selective serotonin reuptake inhibitor (SSRI). Converging evidence suggests that depression is related to brain mitochondrial dysfunction. Our previous studies of MDD in adult and adolescent females suggest that augmentation of SSRI pharmacotherapy with creatine monohydrate (CM) may improve MDD outcomes. Neuroimaging with phosphorus-31 magnetic resonance spectroscopy (31P-MRS) can measure the high-energy phosphorus metabolites in vivo that reflect mitochondrial function. These include phosphocreatine (PCr), a substrate for the creatine kinase reaction that produces adenosine triphosphate. As part of the National Institute of Mental Health’s experimental medicine initiative, we conducted a placebo-controlled doseranging study of adjunctive CM for adolescent females with SSRI-resistant MDD. Participants were randomized to receive placebo or CM 2, 4 or 10 g daily for 8 weeks. Pre- and post-treatment 31P-MRS scans were used to measure frontal lobe PCr, to assess CM’s target engagement with cerebral energy metabolism. Mean frontal lobe PCr increased by 4.6, 4.1 and 9.1 % in the 2, 4 and 10 g groups, respectively; in the placebo group, PCr fell by 0.7 %. There was no group difference in adverse events, weight gain or serum creatinine. Regression analysis of PCr and depression scores across the entire sample showed that frontal lobe PCr was inversely correlated with depression scores (p = 0.02). These results suggest that CM achieves target engagement with brain bioenergetics and that the target is correlated with a clinical signal. Further study of CM as a treatment for adolescent females with SSRI-resistant MDD is warranted. PMID:26907087

  7. Creatine target engagement with brain bioenergetics: a dose-ranging phosphorus-31 magnetic resonance spectroscopy study of adolescent females with SSRI-resistant depression.

    PubMed

    Kondo, Douglas G; Forrest, Lauren N; Shi, Xianfeng; Sung, Young-Hoon; Hellem, Tracy L; Huber, Rebekah S; Renshaw, Perry F

    2016-08-01

    Major depressive disorder (MDD) often begins during adolescence and is projected to become the leading cause of global disease burden by the year 2030. Yet, approximately 40 % of depressed adolescents fail to respond to standard antidepressant treatment with a selective serotonin reuptake inhibitor (SSRI). Converging evidence suggests that depression is related to brain mitochondrial dysfunction. Our previous studies of MDD in adult and adolescent females suggest that augmentation of SSRI pharmacotherapy with creatine monohydrate (CM) may improve MDD outcomes. Neuroimaging with phosphorus-31 magnetic resonance spectroscopy ((31)P-MRS) can measure the high-energy phosphorus metabolites in vivo that reflect mitochondrial function. These include phosphocreatine (PCr), a substrate for the creatine kinase reaction that produces adenosine triphosphate. As part of the National Institute of Mental Health's experimental medicine initiative, we conducted a placebo-controlled dose-ranging study of adjunctive CM for adolescent females with SSRI-resistant MDD. Participants were randomized to receive placebo or CM 2, 4 or 10 g daily for 8 weeks. Pre- and post-treatment (31)P-MRS scans were used to measure frontal lobe PCr, to assess CM's target engagement with cerebral energy metabolism. Mean frontal lobe PCr increased by 4.6, 4.1 and 9.1 % in the 2, 4 and 10 g groups, respectively; in the placebo group, PCr fell by 0.7 %. There was no group difference in adverse events, weight gain or serum creatinine. Regression analysis of PCr and depression scores across the entire sample showed that frontal lobe PCr was inversely correlated with depression scores (p = 0.02). These results suggest that CM achieves target engagement with brain bioenergetics and that the target is correlated with a clinical signal. Further study of CM as a treatment for adolescent females with SSRI-resistant MDD is warranted. PMID:26907087

  8. Moving NMR

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

    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 which delineate the direction into which portable NMR is moving.

  9. Intracellular pH measurements of the whole head and the basal ganglia in chronic liver disease: a phosphorus-31 MR spectroscopy study.

    PubMed

    Patel, N; Forton, D M; Coutts, G A; Thomas, H C; Taylor-Robinson, S D

    2000-09-01

    The purpose of this study was to determine the intracellular pH of the whole head and in voxels localized to the basal ganglia in patients with chronic liver disease using phosphorus-31 magnetic resonance spectroscopy (31P MRS). The study group compromised 82 patients with biopsy-proven cirrhosis (43 Child's grade A, 25 Child's grade B and 14 Child's grade C). Eleven subjects showed no evidence of neuropsychiatric impairment on clinical, psychometric and electrophysiological testing, 37 showed evidence of minimal hepatic encephalopathy and 34 had overt hepatic encephalopathy. Unlocalized 31P MRS of the whole head was performed in 48 patients and 10 healthy volunteers. Localized 31P MRS of the basal ganglia was performed in the 34 patients and in 20 healthy volunteers. The intracellular pH values were calculated from the chemical shift difference between the inorganic phosphate (P) and phosphocreatine (PCr) resonances. The percentage inorganic phosphate (%Pi), phosphocreatine (%PCr) and betaNTP signals, relative to the total 31P signal, and peak area ratios of inorganic phosphate and phosphocreatine, relative to betaNTP were also measured. There were no differences between patients and volunteers in intracellular pH in 31P MR spectra measured from the whole head or the basal ganglia. There was no correlation between the severity of encephalopathy (West Haven criteria) or liver dysfunction (Child score) and intracellular pH values. There was also no significant change in the inorganic phosphate, phosphocreatine or betaNTP resonances in spectra acquired from the whole head. However, in spectra localized to the basal ganglia, there was a significant increase in mean P/NTP (p=0.02) and PCr/NTP (p=0.009). The mean %Pi and mean %PCr were also increased (p=0.06; p=0.05, respectively), but there was no significant change in mean %betaNTP. When the patient population was classified according to the severity of encephalopathy, those with overt disease had a higher mean P

  10. Comparison of Phosphorus Forms in Wet and Dried Animal Manures by Solution Phosphorus-31 Nuclear Magnetic Resonance Spectroscopy and Enzymatic Hydrolysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Both enzymatic hydrolysis and solution 31P nuclear magnetic resonance (NMR) spectroscopy have been used to characterize P compounds in animal manures. However, no comparison of the two methods has been reported in the literature. In this study, we compared P compounds in dairy and poultry manures i...

  11. Strategies for the uses of lanthanide NMR shift probes in the determination of protein structure in solutio. Application to the EF calcium binding site of carp parvalbumin.

    PubMed

    Lee, L; Sykes, B D

    1980-10-01

    The homologous sequences observed for many calcium binding proteins such as parvalbumin, troponin C, the myosin light chains, and calmodulin has lead to the hypothesis that these proteins have homologous structures at the level of their calcium binding sites. This paper discusses the development of a nuclear magnetic resonance (NMR) technique which will enable us to test this structural hypothesis in solution. The technique involves the substitution of a paramagnetic lanthanide ion for the calcium ion which results in lanthanide induced shifts and broadening in the 1H NMR spectrum of the protein. These shifts are sensitive monitors of the precise geometrical orientation of each proton nucleus relative to the metal. The values of several parameters in the equation relating the NMR shifts to the structure are however known as priori. We have attempted to determine these parameters, the orientation and principal elements of the magnetic susceptibility tensor of the protein bound metal, by studying the lanthanide induced shifts for the protein parvalbumin whose structure has been determined by x-ray crystallographic techniques. The interaction of the lanthanide ytterbium with parvalbumin results in high resolution NMR spectra exhibiting a series of resonances with shifts spread over the range 32 to -19 ppm. The orientation and principal elements of the ytterbium magnetic susceptibility tensor have been determined using three assigned NMR resonances, the His-26 C2 and C4 protons and the amino terminal acetyl protons, and seven methyl groups; all with known geometry relative to the EF calcium binding site. The elucidation of these parameters has allowed us to compare the observed spectrum of the nuclei surrounding the EF calcium binding site of parvalbumin with that calculated from the x-ray structure. A significant number of the calculated shifts are larger than any of the observed shifts. We feel that a refinement of the x-ray based proton coordinates will be possible

  12. Lanthanide-cyclodextrin complexes as probes for elucidating optical purity by NMR spectroscopy

    SciTech Connect

    Wenzel, T.J.; Bogyo, M.S.; Lebeau, E.L. )

    1994-06-01

    A multidentate ligand is bonded to cyclodextrins by the reaction of diethylenetriaminepentaacetic dianhydride with 6-mono- and 2-mono(ethylenediamine) derivatives of cyclodextrin. Adding Dy(III) to the cyclodextrin derivatives enhances the enantiomeric resolution in the [sup 1]H NMR spectra of carbionoxamine maleate, doxylamine succinate, pheniramine maleate, propranolol hydrochloride, and tryptophan. The enhancement is more pronounced with the secondary derivative. The Dy(III)-induced shifts can be used to elucidate the geometry of cyclodextrin-substrate inclusion complexes. Lanthanide-induced shifts are reported for complexes of aspartame, tryptophan, propranolol, and 1-anilino-8-naphthalenesulfonate with cyclodextrins, and the relative magnitudes of the shifts agree with previously reported structures of the complexes. 37 refs., 9 figs., 5 tabs.

  13. Chromatographic NMR in NMR solvents

    NASA Astrophysics Data System (ADS)

    Carrara, Caroline; Viel, Stéphane; Delaurent, Corinne; Ziarelli, Fabio; Excoffier, Grégory; Caldarelli, Stefano

    2008-10-01

    Recently, it was demonstrated that pseudo-chromatographic NMR experiments could be performed using typical chromatographic solids and solvents. This first setup yielded improved separation of the spectral components of the NMR spectra of mixtures using PFG self-diffusion measurements. The method (dubbed Chromatographic NMR) was successively shown to possess, in favorable cases, superior resolving power on non-functionalized silica, compared to its LC counterpart. To further investigate the applicability of the method, we studied here the feasibility of Chromatographic NMR in common deuterated solvents. Two examples are provided, using deuterated chloroform and water, for homologous compounds soluble in these solvents, namely aromatic molecules and alcohols, respectively.

  14. In vivo 31P-NMR spectroscopy of chronically stimulated canine skeletal muscle.

    PubMed

    Clark, B J; Acker, M A; McCully, K; Subramanian, H V; Hammond, R L; Salmons, S; Chance, B; Stephenson, L W

    1988-02-01

    Chronic stimulation converts skeletal muscle of mixed fiber type to a uniform muscle made up of type I, fatigue-resistant fibers. Here, the bioenergetic correlates of fatigue resistance in conditioned canine latissimus dorsi are assessed with in vivo phosphorus-31 nuclear magnetic resonance (31P-NMR) spectroscopy. After chronic electrical stimulation, five dogs underwent 31P-NMR spectroscopic and isometric tension measurements on conditioned and contralateral control muscle during stimulation for 200, 300, 500, and 800 ms of an 1,100-ms duty cycle. With stimulation, phosphocreatine (PCr) fell proportional to the degree of stimulation in both conditioned and control muscle but fell significantly less in conditioned muscle at all but the least intense stimulation period (200 ms). Isometric tension, expressed as a tension time index per gram muscle, was significantly greater in the conditioned muscle at the two longest stimulation periods. The overall small change in PCr and the lack of a plateau in tension observed in the conditioned muscle are similar to that seen in cardiac muscle during increased energy demand. This study indicates that the conditioned muscle's markedly enhanced resistance to fatigue is in part the result of its increased capacity for oxidative phosphorylation. PMID:3348365

  15. In vivo sup 31 P-NMR spectroscopy of chronically stimulated canine skeletal muscle

    SciTech Connect

    Clark, B.J. III; McCully, A.K.; Subramanian, H.V.; Hammond, R.L.; Salmons, S.; Chance, B.; Stephenson, L.W. Univ. of Pennsylvania School of Medicine, Philadelphia Univ. of Birmingham )

    1988-02-01

    Chronic stimulation converts skeletal muscle of mixed fiber type to a uniform muscle made up of type I, fatigue-resistant fibers. Here, the bioenergetic correlates of fatigue resistance in conditioned canine latissimus dorsi are assessed with in vivo phosphorus-31 nuclear magnetic resonance ({sup 31}P-NMR) spectroscopy. After chronic electrical stimulation, five dogs underwent {sup 31}P-NMR spectroscopic and isometric tension measurements on conditioned and contralateral control muscle during stimulation for 200, 300, 500, and 800 ms of an 1,100-ms duty cycle. With stimulation, phosphocreatine (PCr) fell proportional to the degree of stimulation in both conditioned and control muscle but fell significantly less in conditioned muscle at all the least intense stimulation period (200 ms). Isometric tension, expressed as a tension time index per gram muscle, was significantly greater in the conditioned muscle at the two longest stimulation periods. The overall small change in PCr and the lack of a plateau in tension observed in the conditioned muscle are similar to that seen in cardiac muscle during increased energy demand. This study indicates that the conditioned muscle's markedly enhanced resistance to fatigue is in part the result of its increased capacity for oxidative phosphorylation.

  16. 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...

  17. 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.

  18. Lectures on pulsed NMR

    SciTech Connect

    Pines, A.

    1986-09-01

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

  19. Lectures on pulsed NMR

    SciTech Connect

    Pines, A.

    1988-08-01

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

  20. NMR logging apparatus

    DOEpatents

    Walsh, David O; Turner, Peter

    2014-05-27

    Technologies including NMR logging apparatus and methods are disclosed. Example NMR logging apparatus may include surface instrumentation and one or more downhole probes configured to fit within an earth borehole. The surface instrumentation may comprise a power amplifier, which may be coupled to the downhole probes via one or more transmission lines, and a controller configured to cause the power amplifier to generate a NMR activating pulse or sequence of pulses. Impedance matching means may be configured to match an output impedance of the power amplifier through a transmission line to a load impedance of a downhole probe. Methods may include deploying the various elements of disclosed NMR logging apparatus and using the apparatus to perform NMR measurements.

  1. Silver and Gold NMR

    PubMed Central

    Zangger, Klaus

    1999-01-01

    Silver and gold, together with copper, form the transition metal group IB elements in the periodic table and possess very different nuclear magnetic resonance (NMR) spectroscopic properties. While there is only one gold isotope (197Au), which has a spin of 3/2 and therefore a quadrupole moment, silver occurs in two isotopic forms (109Ag and 109Au), both of which have a spin 1/2 and similar NMR spectroscopic properties. The unfavorable properties of gold have prevented its NMR spectroscopic investigation thus far. On the other hand, there are several reports of silver NMR. However, the low sensitivity of silver, combined with its long relaxation times have rendered the direct detection of silver possible only with concentrations greater than a few tenth molar. Reviewed here are the general limitations of silver NMR and some techniques to partially overcome these limitations, as well as a summary of currently available chemical shift and scalar coupling data on 109Ag. PMID:18475898

  2. 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.''

  3. Dual Species NMR Oscillator

    NASA Astrophysics Data System (ADS)

    Weber, Joshua; Korver, Anna; Thrasher, Daniel; Walker, Thad

    2016-05-01

    We present progress towards a dual species nuclear magnetic oscillator using synchronous spin exchange optical pumping. By applying the bias field as a sequence of alkali 2 π pulses, we generate alkali polarization transverse to the bias field. The alkali polarization is then modulated at the noble gas resonance so that through spin exchange collisions the noble gas becomes polarized. This novel method of NMR suppresses the alkali field frequency shift by at least a factor of 2500 as compared to longitudinal NMR. We will present details of the apparatus and measurements of dual species co-magnetometry using this method. Research supported by the NSF and Northrop-Grumman Corp.

  4. X-ray diffraction and (1)H NMR in solution: structural determination of lanthanide complexes of a Py(2)N(6)Ac(4) ligand.

    PubMed

    Valencia, L; Martinez, J; Macías, A; Bastida, R; Carvalho, R A; Geraldes, C F G C

    2002-10-01

    Complexes between the Py(2)N(6)Ac(4) (H(4)L) ligand containing four carboxylate pendant arms and trivalent lanthanide ions have been synthesized, and structural studies have been made both in the solid state and aqueous solution. The crystal structures of the La, Ce, Sm, Tb, Dy, Ho, Er, Tm, and Lu complexes, with chemical formulas [LaH(2)L](NO(3)).3H(2)O (1), [Ce(4)L(2)](NO(3))(4).30H(2)O (2), [SmHL].EtOH.3H(2)O (5), [TbHL].EtOH.3H(2)O (8), [DyHL].2EtOH.2H(2)O (9), [HoHL].3H(2)O (10), [ErHL].EtOH.3H(2)O (11) [TmHL].EtOH.3H(2)O (12), and [LuHL].3H(2)O (14), have been determined by single-crystal X-ray crystallography. In the solid state, the complexes of the lighter lanthanide ions La(3+)-Dy(3+) show a 10-coordinated geometry close to a distorted bicapped antiprism, where the carboxylate pendants are situated alternatively above and below the best plane that contains the nitrogen donor atoms. The complexes of the heavier ions, Ho(3+)-Lu(3+), have a 9-coordinated geometry close to distorted tricapped trigonal prism, with one of the pendant carboxylate groups uncoordinated. The ligand is in a "twist-fold" conformation, where the twisting of the pyridine units is accompanied by an overall folding of the major ring of the macrocycle so that the pyridine nitrogen atoms and the metal are far from linear. The aqueous solution structures of the complexes were thoroughly characterized, the diamagnetic ones (La(3+) and Lu(3+)) by their COSY NMR spectra, and the paramagnetic complexes using a linear least-squares fitting of the (1)H LIS (lanthanide-induced shift) and LIR (lanthanide-induced relaxation) data with rhombic magnetic susceptibility tensors. The solution structures obtained for the La(3+)-Dy(3+) complexes (10-coordinate) and for the Tm(3+)-Lu(3+) complexes (9-coordinate) are in very good agreement with the corresponding crystal structures. However, the 10-coordinate structure is still exclusive in solution for the Ho(3+) complex and predominant for the Er(3

  5. Screening proteins for NMR suitability

    PubMed Central

    Yee, Adelinda A.; Semesi, Anthony; Garcia, Maite; Arrowsmith, Cheryl H.

    2014-01-01

    Summary NMR spectroscopy is an invaluable tool in structural genomics. Identification of protein samples that are amenable to structure determination by NMR spectroscopy requires efficient screening. Here, we describe how we prepare multiple samples in parallel and screen by NMR. The method described here is applicable to large structural genomics projects but can easily be scaled down for application to small structural biology projects since all the equipments used are those commonly found in any NMR structural biology laboratory. PMID:24590717

  6. Modern NMR Spectroscopy.

    ERIC Educational Resources Information Center

    Jelinski, Lynn W.

    1984-01-01

    Discusses direct chemical information that can be obtained from modern nuclear magnetic resonance (NMR) methods, concentrating on the types of problems that can be solved. Shows how selected methods provide information about polymers, bipolymers, biochemistry, small organic molecules, inorganic compounds, and compounds oriented in a magnetic…

  7. Enantiodiscrimination by NMR spectroscopy.

    PubMed

    Uccello-Barretta, Gloria; Balzano, Federica; Salvadori, Piero

    2006-01-01

    The analysis of enantiorecognition processes involves the detection of enantiomeric species as well as the study of chiral discrimination mechanisms. In both fields Nuclear Magnetic Resonance (NMR) spectroscopy plays a fundamental role, providing several tools, based on the use of suitable chiral auxiliaries, for observing distinct signals of enantiomers and for investigating the complexation phenomena involved in enantiodiscrimination processes. PMID:17100610

  8. 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.

  9. The NMR phased array.

    PubMed

    Roemer, P B; Edelstein, W A; Hayes, C E; Souza, S P; Mueller, O M

    1990-11-01

    We describe methods for simultaneously acquiring and subsequently combining data from a multitude of closely positioned NMR receiving coils. The approach is conceptually similar to phased array radar and ultrasound and hence we call our techniques the "NMR phased array." The NMR phased array offers the signal-to-noise ratio (SNR) and resolution of a small surface coil over fields-of-view (FOV) normally associated with body imaging with no increase in imaging time. The NMR phased array can be applied to both imaging and spectroscopy for all pulse sequences. The problematic interactions among nearby surface coils is eliminated (a) by overlapping adjacent coils to give zero mutual inductance, hence zero interaction, and (b) by attaching low input impedance preamplifiers to all coils, thus eliminating interference among next nearest and more distant neighbors. We derive an algorithm for combining the data from the phased array elements to yield an image with optimum SNR. Other techniques which are easier to implement at the cost of lower SNR are explored. Phased array imaging is demonstrated with high resolution (512 x 512, 48-cm FOV, and 32-cm FOV) spin-echo images of the thoracic and lumbar spine. Data were acquired from four-element linear spine arrays, the first made of 12-cm square coils and the second made of 8-cm square coils. When compared with images from a single 15 x 30-cm rectangular coil and identical imaging parameters, the phased array yields a 2X and 3X higher SNR at the depth of the spine (approximately 7 cm). PMID:2266841

  10. NMR imaging of materials

    SciTech Connect

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

    1988-03-01

    A method for obtaining at least one petrophysical property of a porous material containing therein at least one preselected fluid, is described, comprising: NMR imaging the material to generate signals dependent upon both M(0) and T/sub 1/ and M(0) and T/sub 2/, generating separate M(0), T/sub 1/ and T/sub 2/ images from the signals, and determining at least one petrophysical property from at least one of the images.

  11. 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

  12. Bayesian reconstruction of projection reconstruction NMR (PR-NMR).

    PubMed

    Yoon, Ji Won

    2014-11-01

    Projection reconstruction nuclear magnetic resonance (PR-NMR) is a technique for generating multidimensional NMR spectra. A small number of projections from lower-dimensional NMR spectra are used to reconstruct the multidimensional NMR spectra. In our previous work, it was shown that multidimensional NMR spectra are efficiently reconstructed using peak-by-peak based reversible jump Markov chain Monte Carlo (RJMCMC) algorithm. We propose an extended and generalized RJMCMC algorithm replacing a simple linear model with a linear mixed model to reconstruct close NMR spectra into true spectra. This statistical method generates samples in a Bayesian scheme. Our proposed algorithm is tested on a set of six projections derived from the three-dimensional 700 MHz HNCO spectrum of a protein HasA. PMID:25218584

  13. Soils, Pores, and NMR

    NASA Astrophysics Data System (ADS)

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

    2010-05-01

    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 natural porous systems. Examples are presented where soil samples from the Selhausen, Merzenhausen (silt loams), and Kaldenkirchen (sandy loam) test sites are investigated by means of Fast Field Cycling Relaxometry at different degrees of saturation. From the change of the relaxation time distributions with decreasing water content and by comparison with conventional water retention curves we conclude that the fraction of immobile water is characterized by T1 < 5 ms. Moreover, the dependence of the relaxation rate on magnetic field strength allows the identification of 2D diffusion at the interfaces as the mechanism which governs the relaxation process (Pohlmeier et al. 2009). T2 relaxation curves are frequently measured for the rapid characterization of soils by means of the CPMG echo train. Basically, they contain the same information about the pore systems like T1 curves, since mostly the overall relaxation is dominated by surface relaxivity and the surface/volume ratio of the pores. However, one must be aware that T2 relaxation is additionally affected by diffusion in internal gradients, and this can be overcome by using sufficiently short echo times and low magnetic fields (Stingaciu et al. 2009). Second, the logic continuation of conventional relaxation measurements is the 2-dimensional experiment, where prior to the final detection of the CPMG echo train an encoding period is applied. This can be T1-encoding by an inversion pulse, or T2 encoding by a sequence of 90 and 180° pulses. During the following evolution time the separately encoded signals can mix and this reveals information about

  14. Catalytic mechanism of α-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 α-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 α,β-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

  15. Catalytic mechanism of α-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 α-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 α,β-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

  16. Summary of Miniature NMR Development

    SciTech Connect

    Friedman, Gennady; Feinerman, Alan

    2000-12-31

    The effort in this project has been in 3 distinct directions: (1) First, they focused on development of miniature microfabricated micro-coil NMR detectors with maximum Signal-to-Noise (SNR) ratio. (2) Secondly, they focused on design of miniature micro-coil NMR detectors that have minimal effect on the NMR spectrum distortions. (3) Lastly they focused on the development of a permanent magnet capable of generating fields on the order of 1 Tesla with better than 10 ppm uniformity.

  17. 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

  18. THz Dynamic Nuclear Polarization NMR.

    PubMed

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

    2011-08-29

    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

  19. Two-dimensional NMR spectroscopy

    SciTech Connect

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

    1987-01-01

    Written for chemists and biochemists who are not NMR spectroscopists, but who wish to use the new techniques of two-dimensional NMR spectroscopy, this book brings together for the first time much of the practical and experimental data needed. It also serves as information source for industrial, academic, and graduate student researchers who already use NMR spectroscopy, but not yet in two dimensions. The authors describe the use of 2-D NMR in a wide variety of chemical and biochemical fields, among them peptides, steroids, oligo- and poly-saccharides, nucleic acids, natural products (including terpenoids, alkaloids, and coal-derived heterocyclics), and organic synthetic intermediates. They consider throughout the book both the advantages and limitations of using 2-D NMR.

  20. Integrative NMR for biomolecular research.

    PubMed

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

    2016-04-01

    NMR spectroscopy is a powerful technique for determining structural and functional features of biomolecules in physiological solution as well as for observing their intermolecular interactions in real-time. However, complex steps associated with its practice have made the approach daunting for non-specialists. We introduce an NMR platform that makes biomolecular NMR spectroscopy much more accessible by integrating tools, databases, web services, and video tutorials that can be launched by simple installation of NMRFAM software packages or using a cross-platform virtual machine that can be run on any standard laptop or desktop computer. The software package can be downloaded freely from the NMRFAM software download page ( http://pine.nmrfam.wisc.edu/download_packages.html ), and detailed instructions are available from the Integrative NMR Video Tutorial page ( http://pine.nmrfam.wisc.edu/integrative.html ). PMID:27023095

  1. Compact orthogonal NMR field sensor

    DOEpatents

    Gerald, II, Rex E.; Rathke, Jerome W.

    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.

  2. Polarization transfer NMR imaging

    DOEpatents

    Sillerud, Laurel O.; van Hulsteyn, David B.

    1990-01-01

    A nuclear magnetic resonance (NMR) image is obtained with spatial information modulated by chemical information. The modulation is obtained through polarization transfer from a first element representing the desired chemical, or functional, information, which is covalently bonded and spin-spin coupled with a second element effective to provide the imaging data. First and second rf pulses are provided at first and second frequencies for exciting the imaging and functional elements, with imaging gradients applied therebetween to spatially separate the nuclei response for imaging. The second rf pulse is applied at a time after the first pulse which is the inverse of the spin coupling constant to select the transfer element nuclei which are spin coupled to the functional element nuclei for imaging. In a particular application, compounds such as glucose, lactate, or lactose, can be labeled with .sup.13 C and metabolic processes involving the compounds can be imaged with the sensitivity of .sup.1 H and the selectivity of .sup.13 C.

  3. 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.

  4. 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.

  5. 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.

  6. NMR characterization of thin films

    DOEpatents

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

    2010-06-15

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

  7. NMR characterization of thin films

    DOEpatents

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

    2008-11-25

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

  8. Automated protein NMR resonance assignments.

    PubMed

    Wan, Xiang; Xu, Dong; Slupsky, Carolyn M; Lin, Guohui

    2003-01-01

    NMR resonance peak assignment is one of the key steps in solving an NMR protein structure. The assignment process links resonance peaks to individual residues of the target protein sequence, providing the prerequisite for establishing intra- and inter-residue spatial relationships between atoms. The assignment process is tedious and time-consuming, which could take many weeks. Though there exist a number of computer programs to assist the assignment process, many NMR labs are still doing the assignments manually to ensure quality. This paper presents (1) a new scoring system for mapping spin systems to residues, (2) an automated adjacency information extraction procedure from NMR spectra, and (3) a very fast assignment algorithm based on our previous proposed greedy filtering method and a maximum matching algorithm to automate the assignment process. The computational tests on 70 instances of (pseudo) experimental NMR data of 14 proteins demonstrate that the new score scheme has much better discerning power with the aid of adjacency information between spin systems simulated across various NMR spectra. Typically, with automated extraction of adjacency information, our method achieves nearly complete assignments for most of the proteins. The experiment shows very promising perspective that the fast automated assignment algorithm together with the new score scheme and automated adjacency extraction may be ready for practical use. PMID:16452794

  9. 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 (μm) requires the knowledge of the surface relaxivity (μm/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 μm. 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.

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

    SciTech Connect

    Matwiyoff, N.A.

    1983-01-01

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

  11. 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

  12. NMR Imaging: Instrumentation and Techniques

    NASA Astrophysics Data System (ADS)

    Tingle, Jeremy Mark

    Available from UMI in association with The British Library. This thesis presents three original contributions to the field of Nuclear Magnetic Resonance (NMR): the experimental framework and analysis for the measurement of a new imaging parameter to describe perfusion; the measurement and analysis of magnetic field inhomogeneity and a practical correction system for their reduction; a novel system for the synchronous control of NMR experiments based on the microprogrammed concept. The thesis begins with an introduction to the theory of NMR. The application of NMR to imaging is also introduced with emphasis on the techniques which developed into those in common use today. Inaccurate determination of the traditional NMR parameters (T_1 and T_2 and the molecular diffusion coefficient) can be caused by non-diffusive fluid movement within the sample. The experimental basis for determining a new imaging parameter --the Perfusion coefficient--is presented. This provides a measure of forced isotropic fluid motion through an organ or tissue. The instrumentation required for conducting NMR experiments is described in order to introduce the contribution made in this area during this research: A sequence controller. The controller is based on the concept of microprogramming and enables completely synchronous output of 128 bits of data. The software for the generation and storage of control data and the regulation of the data to provide experimental control is microcomputer based. It affords precise and accurate regulation of the magnetic field gradients, the rf synthesizer and the spectrometer for spectroscopic and imaging applications. Fundamental to the science of NMR is the presence of a magnetic field. A detailed study of the analysis of magnetic field inhomogeneity in terms of spherical harmonics is presented. The field of a whole body imaging system with poor inhomogeneity was measured and analyzed to determine and describe the components of the inhomogeneity. Finally a

  13. NMR planar microcoil for microanalysis

    NASA Astrophysics Data System (ADS)

    Sorli, B.; Chateaux, J. F.; Quiquerez, L.; Bouchet-Fakri, L.; Briguet, A.; Morin, P.

    2006-11-01

    This article deals with the analysis of small sample volume by using a planar microcoil and a micromachined cavity. This microcoil is used as a nuclear magnetic resonance (NMR) radio frequency detection coil in order to perform in vitro NMR analysis of the sample introduced into the microcavity. It is a real challenging task to develop microsystem for NMR spectrum extraction for smaller and smaller sample volume. Moreover, it is advantageous that these microsystems could be integrated in a Micro Total Analysing System (μ -TAS) as an analysing tool. In this paper, NMR theory, description, fabrication process and electrical characterization of planar microcoils receiver are described. Results obtained on NMR microspectroscopy experiments have been performed on water and ethanol, using a 1 mm diameter planar coil. This microcoil is tuned and matched at 85.13 MHz which is the Larmor frequency of proton in a 2 T magnetic field. This paper has been presented at “3e colloque interdisciplinaire en instrumentation (C2I 2004)”, École Normale Supérieure de Cachan, 29 30 janvier 2004.

  14. Improving NMR Structures of RNA.

    PubMed

    Bermejo, Guillermo A; Clore, G Marius; Schwieters, Charles D

    2016-05-01

    Here, we show that modern solution nuclear magnetic resonance (NMR) structures of RNA exhibit more steric clashes and conformational ambiguities than their crystallographic X-ray counterparts. To tackle these issues, we developed RNA-ff1, a new force field for structure calculation with Xplor-NIH. Using seven published NMR datasets, RNA-ff1 improves covalent geometry and MolProbity validation criteria for clashes and backbone conformation in most cases, relative to both the previous Xplor-NIH force field and the original structures associated with the experimental data. In addition, with smaller base-pair step rises in helical stems, RNA-ff1 structures enjoy more favorable base stacking. Finally, structural accuracy improves in the majority of cases, as supported by complete residual dipolar coupling cross-validation. Thus, the reported advances show great promise in bridging the quality gap that separates NMR and X-ray structures of RNA. PMID:27066747

  15. 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...

  16. Push-through Direction Injectin NMR Automation

    EPA Science Inventory

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

  17. Protein-Inhibitor Interaction Studies Using NMR

    PubMed Central

    Ishima, Rieko

    2015-01-01

    Solution-state NMR has been widely applied to determine the three-dimensional structure, dynamics, and molecular interactions of proteins. The designs of experiments used in protein NMR differ from those used for small-molecule NMR, primarily because the information available prior to an experiment, such as molecular mass and knowledge of the primary structure, is unique for proteins compared to small molecules. In this review article, protein NMR for structural biology is introduced with comparisons to small-molecule NMR, such as descriptions of labeling strategies and the effects of molecular dynamics on relaxation. Next, applications for protein NMR are reviewed, especially practical aspects for protein-observed ligand-protein interaction studies. Overall, the following topics are described: (1) characteristics of protein NMR, (2) methods to detect protein-ligand interactions by NMR, and (3) practical aspects of carrying out protein-observed inhibitor-protein interaction studies. PMID:26361636

  18. "Solvent Effects" in 1H NMR Spectroscopy.

    ERIC Educational Resources Information Center

    Cavaleiro, Jose A. S.

    1987-01-01

    Describes a simple undergraduate experiment in chemistry dealing with the "solvent effects" in nuclear magnetic resonance (NMR) spectroscopy. Stresses the importance of having students learn NMR spectroscopy as a tool in analytical chemistry. (TW)

  19. Deuterium Exchange Kinetics by NMR.

    ERIC Educational Resources Information Center

    Roper, G. C.

    1985-01-01

    Describes a physical chemistry experiment which allows such concepts as kinetics, catalysis, isotope shifts, coupling constants, and the use of nuclear magnetic resonance (NMR) for quantitative work to be covered in the same exercise. Background information, experimental procedures used, and typical results obtained are included. (JN)

  20. QUANTITATIVE 15N NMR SPECTROSCOPY

    EPA Science Inventory

    Line intensities in 15N NMR spectra are strongly influenced by spin-lattice and spin-spin relaxation times, relaxation mechanisms and experimental conditions. Special care has to be taken in using 15N spectra for quantitative purposes. Quantitative aspects are discussed for the 1...

  1. 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.

  2. Two dimensional NMR and NMR relaxation studies of coal structure

    SciTech Connect

    Zilm, K.W.

    1992-05-27

    This report covers the progress made on the title project for the project period. Four major areas of inquiry are being pursued. Advanced solid state NMR methods are being developed to assay the distribution of the various important functional groups that determine the reactivity of coals. Special attention is being paid to methods that are compatible with the very high magic angle sample spinning rates needed for operation at the high magnetic field strengths available today. Polarization inversion methods utilizing the difference in heat capacities of small groups of spins are particularly promising. Methods combining proton-proton spin diffusion with {sup 13}C CPMAS readout are being developed to determine the connectivity of functional groups in coals in a high sensitivity relay type of experiment. Additional work is aimed a delineating the role of methyl group rotation in the proton NMR relaxation behavior of coals.

  3. Solution NMR of large molecules and assemblies†

    PubMed Central

    Foster, Mark P.; McElroy, Craig A.; Amero, Carlos D.

    2008-01-01

    Solution NMR spectroscopy represents a powerful tool for examining the structure and function of biological macromolecules. The advent of multidimensional (2D–4D) NMR, together with the widespread use of uniform isotopic labeling of proteins and RNA with the NMR-active isotopes, 15N and 13C, opened the door to detailed analyses of macromolecular structure, dynamics and interactions of smaller macromolecules (< ~25 kDa). Over the past 10 years, advances in NMR and isotope labeling methods have expanded the range of NMR-tractable targets by at least an order of magnitude. Here we briefly describe the methodological advances that allow NMR spectroscopy of large macromolecules and their complexes, and provide a perspective on the wide range of applications of NMR to biochemical problems. PMID:17209543

  4. Application of 1H and 23Na magic angle spinning NMR spectroscopy to define the HRBC up-taking of MRI contrast agents

    NASA Astrophysics Data System (ADS)

    Calabi, Luisella; Paleari, Lino; Biondi, Luca; Linati, Laura; De Miranda, Mario; Ghelli, Stefano

    2003-09-01

    The up-take of Gd(III) complexes of BOPTA, DTPA, DOTA, EDTP, HPDO3A, and DOTP in HRBC has been evaluated by measuring the lanthanide induced shift (LIS) produced by the corresponding dysprosium complexes (DC) on the MAS-NMR resonances of water protons and free sodium ions. These complexes are important in their use as MRI contrast agents (MRI-CA) in diagnostics. 1H and 23Na MAS-NMR spectra of HRBC suspension, collected at 9.395 T, show only one signal due to extra- and intra-cellular water (or sodium). In MAS spectra, the presence of DC in a cellular compartment produces the LIS of only the nuclei (water proton or sodium) in that cellular compartment and this LIS can be related to the DC concentrations (by the experimental curves of LIS vs. DC concentrations) collected in the physiological solution. To obtain correct results about LIS, the use of MAS technique is mandatory, because it guarantees the only the nuclei staying in the same cellular compartment where the LC is present show the LIS. In all the cases considered, the addition of the DC to HRBC (100% hematocrit) produced a shift of only the extra-cellular water (or sodium) signal and the gradient of concentration ( GC) between extra- and intra-cellular compartments resulted greater than 100:1, when calculated by means of sodium signals. These high values of GC are direct proofs that none of the tested dysprosium complexes crosses the HRBC membrane. Since the DC are iso-structural to the gadolinium complexes the corresponding gadolinium ones (MRI-CA) do not cross the HRBC membrane and, consequently, they are not up-taken in HRBC. The GC values calculated by means of water proton signals resulted much lower than those obtained by sodium signals. This proves that the choice of the isotope is a crucial step in order to use this method in the best way. In fact, GC value depends on the lowest detectable LIS which, in turn, depends on the nature of the LC (lanthanide complex) and the observed isotopes.

  5. REDOR NMR for Drug Discovery

    PubMed Central

    Cegelski, Lynette

    2014-01-01

    Rotational-Echo DOuble-Resonance (REDOR) NMR is a powerful and versatile solid-state NMR measurement that has been recruited to elucidate drug modes of action and to drive the design of new therapeutics. REDOR has been implemented to examine composition, structure, and dynamics in diverse macromolecular and whole-cell systems, including taxol-bound microtubules, enzyme-cofactor-inhibitor ternary complexes, and antibiotic-whole-cell complexes. The REDOR approach involves the integrated design of specific isotopic labeling strategies and the selection of appropriate REDOR experiments. By way of example, this digest illustrates the versatility of the REDOR approach, with an emphasis on the practical considerations of experimental design and data interpretation. PMID:24035486

  6. Two-dimensional NMR spectrometry

    SciTech Connect

    Farrar, T.C.

    1987-06-01

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

  7. NMR investigation of Ag nanoparticles

    NASA Astrophysics Data System (ADS)

    Son, Kwanghyo; Jang, Zeehoon

    2013-01-01

    109Ag nuclear magnetic resonance (NMR) and relaxation measurements have been performed on two powder samples of Ag nanoparticles with average sizes of 20 nm and 80 nm. The measurements have been done in an external field of 9.4 T and in the temperature range 10 K < T < 280 K. The 109Ag NMR spectra for both samples have close to Lorentzian shapes and turn out to be mixtures of homogeneous and inhomogeneous lines. The linewidth Δ ν at room temperature is 1.3 kHz for both samples and gradually increases with decreasing temperature. Both the Knight shift ( K) and the nuclear spin-lattice relaxation rate (1/ T 1) are observed to be almost identical to the values reported for the bulk Ag metal, whereby the Korringa ratio R(= K 2 T 1 T/S) is found to be 2.0 for both samples in the investigated temperature range.

  8. NMR Hyperpolarization Techniques for Biomedicine

    PubMed Central

    Nikolaou, Panayiotis; Goodson, Boyd M.

    2015-01-01

    Recent developments in NMR hyperpolarization have enabled a wide array of new in vivo molecular imaging modalities—ranging from functional imaging of the lungs to metabolic imaging of cancer. This Concept article explores selected advances in methods for the preparation and use of hyperpolarized contrast agents, many of which are already at or near the phase of their clinical validation in patients. PMID:25470566

  9. Measurement of deformations by NMR

    NASA Astrophysics Data System (ADS)

    Bytchenkoff, Dimitri; Rodts, Stéphane

    2015-12-01

    Two NMR data acquisition protocols together with corresponding data processing algorithms for locating macroscopic objects, measuring distances between them or monitoring their displacements or deformations with microscopic precision are presented and discussed. The performance of the methods is demonstrated by applying them to the measurement of deformations of a freely supported beam under loading. We believe that our methods will find their applications in mechanics, civil engineering and medicine.

  10. Hyperpolarized 131Xe NMR spectroscopy

    PubMed Central

    Stupic, Karl F.; Cleveland, Zackary I.; Pavlovskaya, Galina E.; Meersmann, Thomas

    2011-01-01

    Hyperpolarized (hp) 131Xe with up to 2.2% spin polarization (i.e., 5000-fold signal enhancement at 9.4 T) was obtained after separation from the rubidium vapor of the spin-exchange optical pumping (SEOP) process. The SEOP was applied for several minutes in a stopped-flow mode, and the fast, quadrupolar-driven T1 relaxation of this spin I = 3/2 noble gas isotope required a rapid subsequent rubidium removal and swift transfer into the high magnetic field region for NMR detection. Because of the xenon density dependent 131Xe quadrupolar relaxation in the gas phase, the SEOP polarization build-up exhibits an even more pronounced dependence on xenon partial pressure than that observed in 129Xe SEOP. 131Xe is the only stable noble gas isotope with a positive gyromagnetic ratio and shows therefore a different relative phase between hp signal and thermal signal compared to all other noble gases. The gas phase 131Xe NMR spectrum displays a surface and magnetic field dependent quadrupolar splitting that was found to have additional gas pressure and gas composition dependence. The splitting was reduced by the presence of water vapor that presumably influences xenon-surface interactions. The hp 131Xe spectrum shows differential line broadening, suggesting the presence of strong adsorption sites. Beyond hp 131Xe NMR spectroscopy studies, a general equation for the high temperature, thermal spin polarization, P, for spin I⩾1/2 nuclei is presented. PMID:21051249

  11. 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

  12. Scalable NMR spectroscopy with semiconductor chips.

    PubMed

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

    2014-08-19

    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-mm(2) 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

  13. Advanced NMR technology for bioscience and biotechnology

    SciTech Connect

    Hammel, P.C.; Hernandez, G.; Trewhella, J.; Unkefer, C.J.; Boumenthal, D.K.; Kennedy, M.A.; Moore, G.J.

    1998-11-01

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

  14. 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.

  15. Pseudogap in Fe2VGa: NMR evidence

    NASA Astrophysics Data System (ADS)

    Lue, C. S.; Ross, Joseph H.

    2001-02-01

    We report the results of a 51V and 69Ga nuclear magnetic resonance (NMR) study of Fe2VGa at temperatures between 4 and 450 K. The presence of magnetic antisite defects is deduced from the NMR linewidth, which displays a Curie-law temperature dependence. The absence of associated NMR shifts indicates the material to be intrinsically nonmagnetic. At low temperatures the NMR spin-lattice relaxation rate exhibits Korringa behavior, indicating a small carrier density at the Fermi level. At elevated temperatures, the Knight shifts and NMR relaxation rates go over to a thermally activated response, a semiconductor-like behavior. These results are consistent with pseudogap features identified by recent band structure calculations. The Fermi level density of states deduced from NMR is considerably smaller than given by the specific heat coefficient, γ. The electronic properties are compared to the isostructural semimetal Fe2VAl.

  16. Solid-state distortions of nominally square-planar palladium and platinum (R sub 3 P) sub 2 MX sub 2 complexes as determined by a combination of sup 13 C( sup 1 H) and sup 31 P( sup 31 H) NMR spectroscopy

    SciTech Connect

    Rahn, J.A.; Nelson, J.H. ); O'Donnell, D.J.; Pamer, A.R. )

    1989-06-28

    Phosphorus-31 and carbon-13 NMR spectra have been obtained for a series of 20 (R{sub 3}P){sub 2}MX{sub 2} complexes (R{sub 3}P = MePh{sub 2}P and Me{sub 2}PhP; M = Pd, Pt; X = Cl, Br, I, CN, N{sub 3}) in the solid state by cross-polarization and magic-angle-spinning (CP/MAS) techniques. Comparison of these data with spectral data obtained at 300 K in CDCl{sub 3} solutions was made in order to investigate the influence of local symmetry on {sup 31}P and {sup 13}C chemical shifts in the solid state. It was found that most of these compounds, which have regular square-planar geometries in solution, are distorted in the solid state. The solid-state distortions are evidenced by additional {sup 31}P and {sup 13}C resonances in the CP/MAS spectra as compared to the solution spectra. The nature and degree of these distortions are discussed. 25 refs., 2 figs., 6 tabs.

  17. 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

  18. Hyphenated low-field NMR techniques: combining NMR with NIR, GPC/SEC and rheometry.

    PubMed

    Räntzsch, Volker; Wilhelm, Manfred; Guthausen, Gisela

    2016-06-01

    Hyphenated low-field NMR techniques are promising characterization methods for online process analytics and comprehensive offline studies of soft materials. By combining different analytical methods with low-field NMR, information on chemical and physical properties can be correlated with molecular dynamics and complementary chemical information. In this review, we present three hyphenated low-field NMR techniques: a combination of near-infrared spectroscopy and time-domain NMR (TD-NMR) relaxometry, online (1) H-NMR spectroscopy measured directly after size exclusion chromatographic (SEC, also known as GPC) separation and a combination of rheometry and TD-NMR relaxometry for highly viscous materials. Case studies are reviewed that underline the possibilities and challenges of the different hyphenated low-field NMR methods. Copyright © 2015 John Wiley & Sons, Ltd. PMID:25854997

  19. Probing surface interactions by combining NMR cryoporometry and NMR relaxometry

    NASA Astrophysics Data System (ADS)

    Mitchell, J.; Stark, S. C.; Strange, J. H.

    2005-06-01

    To further expand on the understanding of surface interactions at the liquid/solid interface on pore walls, the nuclear magnetic resonance (NMR) techniques of cryoporometry and relaxometry have been combined. The combination of these techniques allows variations in NMR relaxation parameters from pore surface to volume ratio changes and from surface interaction changes to be distinguished. By studying a range of sol-gel silicas from two different sources, it was noted that the relaxation time measurements were not consistent with the pore diameters determined by cryoporometry and N2 gas adsorption. Instead distinctly different relaxivity constants were determined for each absorbate in each of the two brands of silica. It was clear that the relaxation times were modified by more than just the pore geometry. Independent experiments on the two brands of silica suggested that the relaxometry results were heavily influenced by the concentration of paramagnetic relaxation centres in the silica gels. The strength of surface interaction, and hence surface affinity, was seen to depend on the liquid in the pores. Using this difference in surface affinities, binary mixtures of alkanes placed in sol-gel silicas were separated via preferential absorption and their components identified using cryoporometry, whereas the components could not be distinguished in the bulk liquid.

  20. NMR studies of isotopically labeled RNA

    SciTech Connect

    Pardi, A.

    1994-12-01

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

  1. Solid-state NMR and Membrane Proteins

    PubMed Central

    Opella, Stanley J.

    2015-01-01

    The native environment for a membrane protein is a phospholipid bilayer. Because the protein is immobilized on NMR timescales by the interactions within a bilayer membrane, solid-state NMR methods are essential to obtain high-resolution spectra. Approaches have been developed for both unoriented and oriented samples, however, they all rest on the foundation of the most fundamental aspects solid-state NMR, and the chemical shift and homo- and hetero-nuclear dipole-dipole interactions. Solid-state NMR has advanced sufficiently to enable the structures of membrane proteins to be determined under near-native conditions in phospholipid bilayers. PMID:25681966

  2. NMR exposure sensitizes tumor cells to apoptosis.

    PubMed

    Ghibelli, L; Cerella, C; Cordisco, S; Clavarino, G; Marazzi, S; De Nicola, M; Nuccitelli, S; D'Alessio, M; Magrini, A; Bergamaschi, A; Guerrisi, V; Porfiri, L M

    2006-03-01

    NMR technology has dramatically contributed to the revolution of image diagnostic. NMR apparatuses use combinations of microwaves over a homogeneous strong (1 Tesla) static magnetic field. We had previously shown that low intensity (0.3-66 mT) static magnetic fields deeply affect apoptosis in a Ca2+ dependent fashion (Fanelli et al., 1999 FASEBJ., 13;95-102). The rationale of the present study is to examine whether exposure to the static magnetic fields of NMR can affect apoptosis induced on reporter tumor cells of haematopoietic origin. The impressive result was the strong increase (1.8-2.5 fold) of damage-induced apoptosis by NMR. This potentiation is due to cytosolic Ca2+ overload consequent to NMR-promoted Ca2+ influx, since it is prevented by intracellular (BAPTA-AM) and extracellular (EGTA) Ca2+ chelation or by inhibition of plasma membrane L-type Ca2+ channels. Three-days follow up of treated cultures shows that NMR decrease long term cell survival, thus increasing the efficiency of cytocidal treatments. Importantly, mononuclear white blood cells are not sensitised to apoptosis by NMR, showing that NMR may increase the differential cytotoxicity of antitumor drugs on tumor vs normal cells. This strong, differential potentiating effect of NMR on tumor cell apoptosis may have important implications, being in fact a possible adjuvant for antitumor therapies. PMID:16528477

  3. Spin-Exchange-Pumped NMR Gyros

    NASA Astrophysics Data System (ADS)

    Walker, T. G.; Larsen, M. S.

    We present the basic theory governing spin-exchange pumped NMR gyros. We review the basic physics of spin-exchange collisions and relaxation as they pertain to precision NMR. We present a simple model of operation as an NMR oscillator and use it to analyze the dynamic response and noise properties of the oscillator. We discuss the primary systematic errors (differential alkali fields, quadrupole shifts, and offset drifts) that limit the bias stability, and discuss methods to minimize them. We give with a brief overview of a practical implementation and performance of an NMR gyro built by Northrop-Grumman Corporation, and conclude with some comments about future prospects.

  4. Analytical Applications of NMR: Summer Symposium on Analytical Chemistry.

    ERIC Educational Resources Information Center

    Borman, Stuart A.

    1982-01-01

    Highlights a symposium on analytical applications of nuclear magnetic resonance spectroscopy (NMR), discussing pulse Fourier transformation technique, two-dimensional NMR, solid state NMR, and multinuclear NMR. Includes description of ORACLE, an NMR data processing system at Syracuse University using real-time color graphics, and algorithms for…

  5. 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…

  6. 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.

  7. Picoliter H-1 NMR Spectroscopy

    SciTech Connect

    Minard, Kevin R. ); Wind, Robert A. )

    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.

  8. An Integrated Laboratory Project in NMR Spectroscopy.

    ERIC Educational Resources Information Center

    Hudson, Reggie L.; Pendley, Bradford D.

    1988-01-01

    Describes an advanced NMR project that can be done with a 60-MHz continuous-wave proton spectrometer. Points out the main purposes are to give students experience in second-order NMR analysis, the simplification of spectra by raising the frequency, and the effect of non-hydrogen nuclei on proton resonances. (MVL)

  9. NMR Spectroscopy and Its Value: A Primer

    ERIC Educational Resources Information Center

    Veeraraghavan, Sudha

    2008-01-01

    Nuclear magnetic resonance (NMR) spectroscopy is widely used by chemists. Furthermore, the use of NMR spectroscopy to solve structures of macromolecules or to examine protein-ligand interactions is popular. Yet, few students entering graduate education in biological sciences have been introduced to this method or its utility. Over the last six…

  10. Large NMR signals and polarization asymmetries.

    SciTech Connect

    Penttila, S. I.

    1998-11-25

    A large modulation in the series Q-meter can lead to nonlinear NMR signals and asymmetric polarization values. With a careful circuit analysis the nonlinearity can be estimated and corrections to polarization can be determined as a function of the strength of the modulation. We describe the recent LAMPF polarized proton target experiment, its NMR measurement and corrections to the measured polarizations.

  11. 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…

  12. A Guided Inquiry Approach to NMR Spectroscopy

    NASA Astrophysics Data System (ADS)

    Parmentier, Laura E.; Lisensky, George C.; Spencer, Brock

    1998-04-01

    We present a novel way to introduce NMR spectroscopy into the general chemistry curriculum as part of a week-long aspirin project in our one-semester introductory course. Aspirin is synthesized by reacting salicylic acid and acetic anhydride. Purity is determined by titration and IR and NMR spectroscopy. Students compare IR and NMR spectra of their aspirin product to a series of reference spectra obtained by the class. Students are able to interpret the IR spectra of their aspirin using IR data from previous experiments. NMR is introduced by having students collect 1H NMR spectra of a series of reference compounds chosen to include some of the structural features of aspirin and compare spectra and structures of the reference compounds to develop a correlation chart for chemical shifts. This process is done in small groups using shared class data and is guided by a series of questions designed to relate the different kinds of hydrogen atoms to number and position of peaks in the NMR spectrum. Students then identify the peaks in the NMR spectrum of their aspirin product and relate percent purity by titration with spectral results and percent yield. This is an enjoyable project that combines the synthesis of a familiar material with a guided inquiry-based introduction to NMR spectroscopy.

  13. An Inversion Recovery NMR Kinetics Experiment

    ERIC Educational Resources Information Center

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

    2011-01-01

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

  14. Robust, integrated computational control of NMR experiments to achieve optimal assignment by ADAPT-NMR.

    PubMed

    Bahrami, Arash; Tonelli, Marco; Sahu, Sarata C; Singarapu, Kiran K; Eghbalnia, Hamid R; Markley, John L

    2012-01-01

    ADAPT-NMR (Assignment-directed Data collection Algorithm utilizing a Probabilistic Toolkit in NMR) represents a groundbreaking prototype for automated protein structure determination by nuclear magnetic resonance (NMR) spectroscopy. With a [(13)C,(15)N]-labeled protein sample loaded into the NMR spectrometer, ADAPT-NMR delivers complete backbone resonance assignments and secondary structure in an optimal fashion without human intervention. ADAPT-NMR achieves this by implementing a strategy in which the goal of optimal assignment in each step determines the subsequent step by analyzing the current sum of available data. ADAPT-NMR is the first iterative and fully automated approach designed specifically for the optimal assignment of proteins with fast data collection as a byproduct of this goal. ADAPT-NMR evaluates the current spectral information, and uses a goal-directed objective function to select the optimal next data collection step(s) and then directs the NMR spectrometer to collect the selected data set. ADAPT-NMR extracts peak positions from the newly collected data and uses this information in updating the analysis resonance assignments and secondary structure. The goal-directed objective function then defines the next data collection step. The procedure continues until the collected data support comprehensive peak identification, resonance assignments at the desired level of completeness, and protein secondary structure. We present test cases in which ADAPT-NMR achieved results in two days or less that would have taken two months or more by manual approaches. PMID:22427982

  15. NMR and MRI apparatus and method

    DOEpatents

    Clarke, John; Kelso, Nathan; Lee, SeungKyun; Moessle, Michael; Myers, Whittier; McDermott, Robert; ten Haken, Bernard; Pines, Alexander; Trabesinger, Andreas

    2007-03-06

    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. Additional signal to noise benefits are obtained by use of a low noise polarization coil, comprising litz wire or superconducting materials. 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.

  16. Probing Cancer Cell Metabolism Using NMR Spectroscopy.

    PubMed

    Hollinshead, Kate E R; Williams, Debbie S; Tennant, Daniel A; Ludwig, Christian

    2016-01-01

    Altered cellular metabolism is now accepted to be at the core of many diseases including cancer. Over the past 20 years, NMR has become a core technology to study these metabolic perturbations in detail. This chapter reviews current NMR-based methods for steady-state metabolism and, in particular, the use of non-radioactive stable isotope-enriched tracers. Opportunities and challenges for each method, such as 1D (1)H NMR spectroscopy and (13)C carbon-based NMR spectroscopic methods, are discussed. Ultimately, the combination of NMR and mass spectra as orthogonal technologies are required to compensate for the drawbacks of each technique when used singly are discussed. PMID:27325263

  17. Background suppression in MAS NMR

    NASA Astrophysics Data System (ADS)

    White, Jeffery L.; Beck, Larry W.; Ferguson, David B.; Haw, James F.

    Pulse sequences for suppressing background signals from spinning modules used in magic-angle spinning NMR are described. These pulse sequences are based on spatially selective composite 90° pulses originally reported by Bax, which provide for no net excitation of spins outside the homogeneous region of the coil. We have achieved essentially complete suppression of background signals originating from our Vespel spinning module (which uses a free-standing coil) in both 1H and 13C spectra without notable loss in signal intensity. Successful modification of both Bloch decay and cross-polarization pulse sequences to include spatially selective pulses was essential to acquire background-free spectra for weak samples. Background suppression was also found to be particularly valuable for both T1 and T1 ϱ, relaxation measurements.

  18. NMR solution structure of butantoxin.

    PubMed

    Holaday, S K; Martin, B M; Fletcher, P L; Krishna, N R

    2000-07-01

    The NMR structure of a new toxin, butantoxin (BuTX), which is present in the venoms of the three Brazilian scorpions Tityus serrulatus, Tityus bahiensis, and Tityus stigmurus, has been investigated. This toxin was shown to reversibly block the Shaker B potassium channels (K(d) approximately 660 nM) and inhibit the proliferation of T-cells and the interleukin-2 production of antigen-stimulated T-helper cells. BuTX is a 40 amino acid basic protein stabilized by the four disulfide bridges: Cys2-Cys5, Cys10-Cys31, Cys16-Cys36, and Cys20-Cys38. The latter three are conserved among all members of the short-chain scorpion toxin family, while the first is unique to BuTX. The three-dimensional structure of BuTX was determined using (1)H-NMR spectroscopy. NOESY, phase sensitive COSY (PH-COSY), and amide hydrogen exchange data were used to generate constraints for molecular modeling calculations. Distance geometry and simulated annealing calculations were performed to generate a family of 49 structures free of constraint violations. The secondary structure of BuTX consists of a short 2(1/2) turn alpha-helix (Glu15-Phe23) and a beta-sheet. The beta-sheet is composed of two well-defined antiparallel strands (Gly29-Met32 and Lys35-Cys38) connected by a type-I' beta-turn (Asn33-Asn34). Residues Cys5-Ala9 form a quasi-third strand of the beta-sheet. The N-terminal C2-C5 disulfide bridge unique to this toxin does not appear to confer stability to the protein. PMID:10864437

  19. Enantioselective outer-sphere complexation of lanthanide(III) tris (pyridine-2,6-dicarboxylate) chelates with vitamin B 12 derivatives. An NMR and CD study

    NASA Astrophysics Data System (ADS)

    Meskers, Stefan C. J.; Dekkers, Harry P. J. M.

    1999-08-01

    The binding of three corrinoids, cyanocobalarnin (vitamin B 12, CNCbl), aquacobalamin (vitamin B 12a, H 2OCbl +) and dicyanocobinamide ((CN) 2Cbi), collectively denoted by Q, to the Δ- and Λ-enantiomer of Ln(DPA) 33- complexes (Ln=lanthanide, DPA=2,6-pyridine dicarboxylate) in aqueous solution at room temperature is investigated by NMR and Circular Dichroism (CD) spectroscopy. Tb(DPA) 33- induces shifts of the 1H-NMR resonances of Q. A formula, describing the dipolar interaction between the proton spin and the paramagnetic moment of the lanthanide complex, is fitted to the lanthanide induced shifts, yielding the position of Tb(DPA) 33- and the orientation of its magnetic axis with respect to the corrinoid. The magnitude of the shifts provide the value of Kavg, an average of the association constants of the two diastereomeric complexes {Δ-Tb(DPA) 33-Q) and {Λ-Tb(DPA) 33-Q}. We find Kavg=4±0.5 (B 12) and 0.8±0.2 M -1 ((CN) 2Cbi). The value for H 2OCbl + depends strongly on the solution's ionic strength I: Kavg=(7±1)×10 1, 22±5 and 16±7 M -1 at I=0.007, 0.12 and 0.22 M, respectively. The addition of the corrinoids to a (racemic) solution of Nd(DPA) 33-, induces CD in the electronic Nd(III) transitions in the 700-800 nm region (ICD). This Pfeiffer effect is attributed to an excess of Λ-Nd(DPA) 33- in the enantioselective, outer-sphere association with the corrinoids. From the magnitude of the ICD as a function of [Q], in conjunction with the (indirectly) determined CD effect of Λ-Nd(DPA) 33-, values are determined for KΔ- KΛ. We find KΔ- KΛ=-24±2 M -1 for H 2OCbl + at pH 6.7 and I=0.12 M and -12±2 M -1 at I=0.22 M; -4.4±0.5 M -1 for CNCbl and -0.9±0.3 M -1 for (CN) 2Cbi. Adopting the view that in the lanthanide series Ln(DPA) 33- chelates are isostructural, the results of the NMR and CD experiments are combined to estimate the enantioselectivity in the binding Eb, defined as ( KΔ- KΛ)/2 Kavg. We find Eb=-0.5±0.2 for H 2OCbl +, -0.7±0.2 for CNCbl

  20. An Introduction to Biological NMR Spectroscopy*

    PubMed Central

    Marion, Dominique

    2013-01-01

    NMR spectroscopy is a powerful tool for biologists interested in the structure, dynamics, and interactions of biological macromolecules. This review aims at presenting in an accessible manner the requirements and limitations of this technique. As an introduction, the history of NMR will highlight how the method evolved from physics to chemistry and finally to biology over several decades. We then introduce the NMR spectral parameters used in structural biology, namely the chemical shift, the J-coupling, nuclear Overhauser effects, and residual dipolar couplings. Resonance assignment, the required step for any further NMR study, bears a resemblance to jigsaw puzzle strategy. The NMR spectral parameters are then converted into angle and distances and used as input using restrained molecular dynamics to compute a bundle of structures. When interpreting a NMR-derived structure, the biologist has to judge its quality on the basis of the statistics provided. When the 3D structure is a priori known by other means, the molecular interaction with a partner can be mapped by NMR: information on the binding interface as well as on kinetic and thermodynamic constants can be gathered. NMR is suitable to monitor, over a wide range of frequencies, protein fluctuations that play a crucial role in their biological function. In the last section of this review, intrinsically disordered proteins, which have escaped the attention of classical structural biology, are discussed in the perspective of NMR, one of the rare available techniques able to describe structural ensembles. This Tutorial is part of the International Proteomics Tutorial Programme (IPTP 16 MCP). PMID:23831612

  1. MAS NMR of HIV-1 protein assemblies

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  2. Scalar operators in solid-state NMR

    SciTech Connect

    Sun, Boqin

    1991-11-01

    Selectivity and resolution of solid-state NMR spectra are determined by dispersion of local magnetic fields originating from relaxation effects and orientation-dependent resonant frequencies of spin nuclei. Theoretically, the orientation-dependent resonant frequencies can be represented by a set of irreducible tensors. Among these tensors, only zero rank tensors (scalar operators) are capable of providing high resolution NMR spectra. This thesis presents a series of new developments in high resolution solid-state NMR concerning the reconstruction of various scalar operators motion in solid C{sub 60} is analyzed.

  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. MAS NMR of HIV-1 protein assemblies.

    PubMed

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

    2015-04-01

    The negative global impact of the AIDS pandemic is well known. In this perspective article, the utility of magic angle spinning (MAS) NMR spectroscopy to answer pressing questions related to the structure and dynamics of HIV-1 protein assemblies is examined. In recent years, MAS NMR has undergone major technological developments enabling studies of large viral assemblies. We discuss some of these evolving methods and technologies and provide a perspective on the current state of MAS NMR as applied to the investigations into structure and dynamics of HIV-1 assemblies of CA capsid protein and of Gag maturation intermediates. PMID:25797001

  5. On electrophoretic NMR. Exploring high conductivity samples

    NASA Astrophysics Data System (ADS)

    Bielejewski, Michał; 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.

  6. 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.

  7. NMR data handbook for biomedical applications

    SciTech Connect

    Beall, P.T.; Amtey, S.R.; Kasturi, S.R.

    1984-01-01

    The text is divided into 10 chapters, each of which covers a specific block of material and has its own references. The volume is meant to serve as a laboratory handbook and a desk reference, containing basic NMR theory, useful formulae and physical constants, and compiled data from the NMR literature. The volume attempts to cover the development of biological NMR through several decades of in vitro experiments that have laid the groundwork for and pointed to profitable areas of investigation for new in vivo techniques.

  8. 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…

  9. NMR and optical studies of piezoelectric polymers

    SciTech Connect

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

    1993-01-01

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

  10. NMR Methods to Study Dynamic Allostery

    PubMed Central

    Grutsch, Sarina; Brüschweiler, Sven; Tollinger, Martin

    2016-01-01

    Nuclear magnetic resonance (NMR) spectroscopy provides a unique toolbox of experimental probes for studying dynamic processes on a wide range of timescales, ranging from picoseconds to milliseconds and beyond. Along with NMR hardware developments, recent methodological advancements have enabled the characterization of allosteric proteins at unprecedented detail, revealing intriguing aspects of allosteric mechanisms and increasing the proportion of the conformational ensemble that can be observed by experiment. Here, we present an overview of NMR spectroscopic methods for characterizing equilibrium fluctuations in free and bound states of allosteric proteins that have been most influential in the field. By combining NMR experimental approaches with molecular simulations, atomistic-level descriptions of the mechanisms by which allosteric phenomena take place are now within reach. PMID:26964042

  11. Epitope mapping by solution NMR spectroscopy.

    PubMed

    Bardelli, M; Livoti, E; Simonelli, L; Pedotti, M; Moraes, A; Valente, A P; Varani, L

    2015-06-01

    Antibodies play an ever more prominent role in basic research as well as in the biotechnology and pharmaceutical sectors. Characterizing their epitopes, that is, the region that they recognize on their target molecule, is useful for purposes ranging from molecular biology research to vaccine design and intellectual property protection. Solution NMR spectroscopy is ideally suited to the atomic level characterization of intermolecular interfaces and, as a consequence, to epitope discovery. Here, we illustrate how NMR epitope mapping can be used to rapidly and accurately determine protein antigen epitopes. The basic concept is that differences in the NMR signal of an antigen free or bound by an antibody will identify epitope residues. NMR epitope mapping provides more detailed information than mutagenesis or peptide mapping and can be much more rapid than X-ray crystallography. Advantages and drawbacks of this technique are discussed together with practical considerations. PMID:25726811

  12. 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.

  13. A New Microcell Technique for NMR Analysis.

    ERIC Educational Resources Information Center

    Yu, Sophia J.

    1987-01-01

    Describes a new laboratory technique for working with small samples of compounds used in nuclear magnetic resonance (NMR) analysis. Demonstrates how microcells can be constructed for each experiment and samples can be recycled. (TW)

  14. Interfaces in polymer nanocomposites - An NMR study

    NASA Astrophysics Data System (ADS)

    Böhme, Ute; Scheler, Ulrich

    2016-03-01

    Nuclear Magnetic Resonance (NMR) is applied for the investigation of polymer nanocomposites. Solid-state NMR is applied to study the modification steps to compatibilize layered double hydroxides with non-polar polymers. 1H relaxation NMR gives insight on the polymer dynamics over a wide range of correlation times. For the polymer chain dynamics the transverse relaxation time T2 is most suited. In this presentation we report on two applications of T2 measurements under external mechanical stress. In a low-field system relaxation NMR studies are performed in-situ under uniaxial stress. High-temperature experiments in a Couette cell permit the investigation of the polymer dynamics in the melt under shear flow.

  15. NMR-Assisted Molecular Docking Methodologies.

    PubMed

    Sturlese, Mattia; Bellanda, Massimo; Moro, Stefano

    2015-08-01

    Nuclear magnetic resonance (NMR) spectroscopy and molecular docking are regularly being employed as helpful tools of drug discovery research. Molecular docking is an extremely rapid method to evaluate possible binders from a large chemical library in a fast and cheap manner. NMR techniques can directly detect a protein-ligand interaction, can determine the corresponding association constant, and can consistently identify the ligand binding cavity. Consequently, molecular docking and NMR techniques are naturally complementary techniques where the combination of the two has the potential to improve the overall efficiency of drug discovery process. In this review, we would like to summarize the state of the art of docking methods which have been recently bridged to NMR experiments to identify novel and effective therapeutic drug candidates. PMID:27490497

  16. Rheology of Blood by NMR

    NASA Astrophysics Data System (ADS)

    Han, Song-I.; Marseille, Oliver; Gehlen, Christa; Blümich, Bernhard

    2001-09-01

    Pipe flow of blood in tubes of 1 and 7 mm inner diameter, respectively, was investigated employing two-dimensional NMR velocity imaging and PFG propagator measurements at different Reynolds numbers between 10 and 3500. The results are compared to flow of a water/glycerol mixture of matching viscosity under identical conditions. The transition from laminar to turbulent flow is observed by both a flattening of the velocity profile and a change of the propagator shape. For blood flow this transition is found to be shifted toward higher Reynolds numbers as compared to the transition of the water/glycerol mixture. This observation is in agreement with predictions from hydraulic measurements and is a consequence of the non-Newtonian flow characteristics of blood as a suspension of erythrocytes and plasma. Likewise, a deviation from the laminar flow condition is observed for blood at low Reynolds numbers between 10 and 100. This phenomenon is unknown for Newtonian liquids and is explained by the onset of a geometrical arrangement of the erythrocytes, the so-called rouleaux effect.

  17. Rheology of blood by NMR.

    PubMed

    Han, S I; Marseille, O; Gehlen, C; Blümich, B

    2001-09-01

    Pipe flow of blood in tubes of 1 and 7 mm inner diameter, respectively, was investigated employing two-dimensional NMR velocity imaging and PFG propagator measurements at different Reynolds numbers between 10 and 3500. The results are compared to flow of a water/glycerol mixture of matching viscosity under identical conditions. The transition from laminar to turbulent flow is observed by both a flattening of the velocity profile and a change of the propagator shape. For blood flow this transition is found to be shifted toward higher Reynolds numbers as compared to the transition of the water/glycerol mixture. This observation is in agreement with predictions from hydraulic measurements and is a consequence of the non-Newtonian flow characteristics of blood as a suspension of erythrocytes and plasma. Likewise, a deviation from the laminar flow condition is observed for blood at low Reynolds numbers between 10 and 100. This phenomenon is unknown for Newtonian liquids and is explained by the onset of a geometrical arrangement of the erythrocytes, the so-called rouleaux effect. PMID:11531367

  18. 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.

  19. Frontiers of NMR in Molecular Biology

    SciTech Connect

    1999-08-25

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

  20. NMR studies of multiphase flows II

    SciTech Connect

    Altobelli, S.A.; Caprihan, A.; Fukushima, E.

    1995-12-31

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

  1. NMR of Membrane Proteins: Beyond Crystals.

    PubMed

    Rajesh, Sundaresan; Overduin, Michael; Bonev, Boyan B

    2016-01-01

    Membrane proteins are essential for the flow of signals, nutrients and energy between cells and between compartments of the cell. Their mechanisms can only be fully understood once the precise structures, dynamics and interactions involved are defined at atomic resolution. Through advances in solution and solid state NMR spectroscopy, this information is now available, as demonstrated by recent studies of stable peripheral and transmembrane proteins. Here we highlight recent cases of G-protein coupled receptors, outer membrane proteins, such as VDAC, phosphoinositide sensors, such as the FAPP-1 pleckstrin homology domain, and enzymes including the metalloproteinase MMP-12. The studies highlighted have resulted in the determination of the 3D structures, dynamical properties and interaction surfaces for membrane-associated proteins using advanced isotope labelling strategies, solubilisation systems and NMR experiments designed for very high field magnets. Solid state NMR offers further insights into the structure and multimeric assembly of membrane proteins in lipid bilayers, as well as into interactions with ligands and targets. Remaining challenges for wider application of NMR to membrane structural biology include the need for overexpression and purification systems for the production of isotope-labelled proteins with fragile folds, and the availability of only a few expensive perdeuterated detergents.Step changes that may transform the field include polymers, such as styrene maleic acid, which obviate the need for detergent altogether, and allow direct high yield purification from cells or membranes. Broader demand for NMR may be facilitated by MODA software, which instantly predicts membrane interactive residues that can subsequently be validated by NMR. In addition, recent developments in dynamic nuclear polarization NMR instrumentation offer a remarkable sensitivity enhancement from low molarity samples and cell surfaces. These advances illustrate the current

  2. Multidimensional NMR spectroscopy in a single scan.

    PubMed

    Gal, Maayan; Frydman, Lucio

    2015-11-01

    Multidimensional NMR has become one of the most widespread spectroscopic tools available to study diverse structural and functional aspects of organic and biomolecules. A main feature of multidimensional NMR is the relatively long acquisition times that these experiments demand. For decades, scientists have been working on a variety of alternatives that would enable NMR to overcome this limitation, and deliver its data in shorter acquisition times. Counting among these methodologies is the so-called ultrafast (UF) NMR approach, which in principle allows one to collect arbitrary multidimensional correlations in a single sub-second transient. By contrast to conventional acquisitions, a main feature of UF NMR is a spatiotemporal manipulation of the spins that imprints the chemical shift and/or J-coupling evolutions being sought, into a spatial pattern. Subsequent gradient-based manipulations enable the reading out of this information and its multidimensional correlation into patterns that are identical to those afforded by conventional techniques. The current review focuses on the fundamental principles of this spatiotemporal UF NMR manipulation, and on a few of the methodological extensions that this form of spectroscopy has undergone during the years. PMID:26249041

  3. 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 μM taurine solutions, which is the level of sensitivity necessary for biological samples.

  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. 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…

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

    DOEpatents

    Fukushima, Eiichi; Roeder, Stephen B. W.; Assink, Roger A.; Gibson, Atholl A. V.

    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.

  7. Calibration of NMR well logs from carbonate reservoirs with laboratory NMR measurements and μXRCT

    SciTech Connect

    Mason, Harris E.; Smith, Megan M.; Hao, Yue; Carroll, Susan A.

    2014-12-31

    The use of nuclear magnetic resonance (NMR) well log data has the potential to provide in-situ porosity, pore size distributions, and permeability of target carbonate CO₂ storage reservoirs. However, these methods which have been successfully applied to sandstones have yet to be completely validated for carbonate reservoirs. Here, we have taken an approach to validate NMR measurements of carbonate rock cores with independent measurements of permeability and pore surface area to volume (S/V) distributions using differential pressure measurements and micro X-ray computed tomography (μXRCT) imaging methods, respectively. We observe that using standard methods for determining permeability from NMR data incorrectly predicts these values by orders of magnitude. However, we do observe promise that NMR measurements provide reasonable estimates of pore S/V distributions, and with further independent measurements of the carbonate rock properties that universally applicable relationships between NMR measured properties may be developed for in-situ well logging applications of carbonate reservoirs.

  8. BOOK REVIEW: NMR Imaging of Materials

    NASA Astrophysics Data System (ADS)

    Blümich, Bernhard

    2003-09-01

    Magnetic resonance imaging (MRI) of materials is a field of increasing importance. Applications extend from fundamental science like the characterization of fluid transport in porous rock, catalyst pellets and hemodialysers into various fields of engineering for process optimization and product quality control. While the results of MRI imaging are being appreciated by a growing community, the methods of imaging are far more diverse for materials applications than for medical imaging of human beings. Blümich has delivered the first book in this field. It was published in hardback three years ago and is now offered as a paperback for nearly half the price. The text provides an introduction to MRI imaging of materials covering solid-state NMR spectroscopy, imaging methods for liquid and solid samples, and unusual MRI in terms of specialized approaches to spatial resolution such as an MRI surface scanner. The book represents an excellent and thorough treatment which will help to grow research in materials MRI. Blümich developed the treatise over many years for his research students, graduates in chemistry, physics and engineering. But it may also be useful for medical students looking for a less formal discussion of solid-state NMR spectroscopy. The structure of this book is easy to perceive. The first three chapters cover an introduction, the fundamentals and methods of solid-state NMR spectroscopy. The book starts at the ground level where no previous knowledge about NMR is assumed. Chapter 4 discusses a wide variety of transformations beyond the Fourier transformation. In particular, the Hadamard transformation and the 'wavelet' transformation are missing from most related books. This chapter also includes a description of noise-correlation spectroscopy, which promises the imaging of large objects without the need for extremely powerful radio-frequency transmitters. Chapters 5 and 6 cover basic imaging methods. The following chapter about the use of relaxation and

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

    SciTech Connect

    Osbakken, M.; Haselgrove, J.

    1987-01-01

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

  10. Theoretical NMR correlations based Structure Discussion

    PubMed Central

    2011-01-01

    The constitutional assignment of natural products by NMR spectroscopy is usually based on 2D NMR experiments like COSY, HSQC, and HMBC. The actual difficulty of the structure elucidation problem depends more on the type of the investigated molecule than on its size. The moment HMBC data is involved in the process or a large number of heteroatoms is present, a possibility of multiple solutions fitting the same data set exists. A structure elucidation software can be used to find such alternative constitutional assignments and help in the discussion in order to find the correct solution. But this is rarely done. This article describes the use of theoretical NMR correlation data in the structure elucidation process with WEBCOCON, not for the initial constitutional assignments, but to define how well a suggested molecule could have been described by NMR correlation data. The results of this analysis can be used to decide on further steps needed to assure the correctness of the structural assignment. As first step the analysis of the deviation of carbon chemical shifts is performed, comparing chemical shifts predicted for each possible solution with the experimental data. The application of this technique to three well known compounds is shown. Using NMR correlation data alone for the description of the constitutions is not always enough, even when including 13C chemical shift prediction. PMID:21797997

  11. NMR studies of cation transport across membranes

    SciTech Connect

    Shochet, N.R.

    1985-01-01

    /sup 23/Na NMR Studies of cation transport across membranes were conducted both on model and biological membranes. Two ionophores, the carrier monensin and the channel-former gramicidin, were chosen to induce cation transport in large unilamellar phosphatidylcholine vesicles. The distinction between the NMR signals arising from the two sides of the membrane was achieved by the addition of an anionic paramagnetic shift reagent to the outer solution. The kinetics of the cation transport across the membrane was observed simultaneously monitoring the changes in the /sup 23/Na NMR signals of both compartments. Two mathematical models were developed for the estimation of the transport parameters of the monensin- and gramicidin-induced cation transport. The models were able to fit the experimental data very well. A new method for the estimation of the volume trapped inside the vesicles was developed. The method uses the relative areas of the intra- and extravesicular NMR signals arising from a suspension of vesicles bathed in the same medium they contain, as a measure for the relative volumes of these compartments. Sodium transport across biological membranes was studied by /sup 23/ NMR, using suspensions of cultured nerve cells. The sodium influx through voltage-gated channels was studied using the channel modifier batrachotoxin in combination with scorpion toxin.

  12. NMR structural studies on antifreeze proteins.

    PubMed

    Sönnichsen, F D; Davies, P L; Sykes, B D

    1998-01-01

    Antifreeze proteins (AFPs) are a structurally diverse class of proteins that bind to ice and inhibit its growth in a noncolligative manner. This adsorption-inhibition mechanism operating at the ice surface results in a lowering of the (nonequilibrium) freezing point below the melting point. A lowering of approximately 1 degree C, which is sufficient to prevent fish from freezing in ice-laden seawater, requires millimolar AFP levels in the blood. The solubility of AFPs at these millimolar concentrations and the small size of the AFPs (typically 3-15 kDa) make them ideal subjects for NMR analysis. Although fish AFPs are naturally abundant, seasonal expression, restricted access to polar fishes, and difficulties in separating numerous similar isoforms have made protein expression the method of choice for producing AFPs for structural studies. Expression of recombinant AFPs has also facilitated NMR analysis by permitting isotopic labeling with 15N and 13C and has permitted mutations to be made to help with the interpretation of NMR data. NMR analysis has recently solved two AFP structures and provided valuable information about the disposition of ice-binding side chains in a third. The potential exists to solve other AFP structures, including the newly described insect AFPs, and to use solid-state NMR techniques to address fundamental questions about the nature of the interaction between AFPs and ice. PMID:9923697

  13. Remote tuning of NMR probe circuits.

    PubMed

    Kodibagkar, V D; Conradi, M S

    2000-05-01

    There are many circumstances in which the probe tuning adjustments cannot be located near the rf NMR coil. These may occur in high-temperature NMR, low-temperature NMR, and in the use of magnets with small diameter access bores. We address here circuitry for connecting a fixed-tuned probe circuit by a transmission line to a remotely located tuning network. In particular, the bandwidth over which the probe may be remotely tuned while keeping the losses in the transmission line acceptably low is considered. The results show that for all resonant circuit geometries (series, parallel, series-parallel), overcoupling of the line to the tuned circuit is key to obtaining a large tuning bandwidth. At equivalent extents of overcoupling, all resonant circuit geometries have nearly equal remote tuning bandwidths. Particularly for the case of low-loss transmission line, the tuning bandwidth can be many times the tuned circuit's bandwidth, f(o)/Q. PMID:10783273

  14. 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

  15. Review of NMR characterization of pyrolysis oils

    DOE PAGESBeta

    Hao, Naijia; Ben, Haoxi; Yoo, Chang Geun; Adhikari, Sushil; Ragauskas, Arthur J.

    2016-08-24

    Here, pyrolysis of renewable biomass has been developed as a method to produce green fuels and chemicals in response to energy security concerns as well as to alleviate environmental issues incurred with fossil fuel usage. However, pyrolysis oils still have limited commercial application, mainly because unprocessed oils cannot be readily blended with current petroleum-based transportation fuels. To better understand these challenges, researchers have applied diverse characterization techniques in the development of bio-oil studies. In particular, nuclear magnetic resonance (NMR) is a key spectroscopic characterization method through analysis of bio-oil components. This review highlights the NMR strategies for pyrolysis oil characterizationmore » and critically discusses the applications of 1H, 13C, 31P, 19F, and two-dimensional (2-D NMR) analyses such as heteronuclear single quantum correlation (HSQC) in representative pyrolysis oil studies.« less

  16. A modularized pulse programmer for NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Mao, Wenping; Bao, Qingjia; Yang, Liang; Chen, Yiqun; Liu, Chaoyang; Qiu, Jianqing; Ye, Chaohui

    2011-02-01

    A modularized pulse programmer for a NMR spectrometer is described. It consists of a networked PCI-104 single-board computer and a field programmable gate array (FPGA). The PCI-104 is dedicated to translate the pulse sequence elements from the host computer into 48-bit binary words and download these words to the FPGA, while the FPGA functions as a sequencer to execute these binary words. High-resolution NMR spectra obtained on a home-built spectrometer with four pulse programmers working concurrently demonstrate the effectiveness of the pulse programmer. Advantages of the module include (1) once designed it can be duplicated and used to construct a scalable NMR/MRI system with multiple transmitter and receiver channels, (2) it is a totally programmable system in which all specific applications are determined by software, and (3) it provides enough reserve for possible new pulse sequences.

  17. 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.

  18. 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

  19. 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.

  20. Tritiation methods and tritium NMR spectroscopy

    SciTech Connect

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

    1991-09-01

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

  1. 1H NMR relaxation in urea

    NASA Astrophysics Data System (ADS)

    Taylor, R. E.; Bacher, Alfred D.; Dybowski, C.

    2007-11-01

    Proton NMR spin-lattice relaxation times T1 were measured for urea as a function of temperature. An activation energy of 46.3 ± 4.7 kJ/mol was extracted and compared with the range of 38-65 kJ/mol previously reported in the literature as measured by different magnetic resonance techniques. In addition, proton NMR spin-lattice relaxation times in the rotating frame T1 ρ were measured as a function of temperature. These measurements provide acquisition conditions for the 13C and 15N CP/MAS spectra of pure urea in the crystalline phase.

  2. 13C NMR Metabolomics: INADEQUATE Network Analysis

    PubMed Central

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

    2015-01-01

    The many advantages of 13C NMR are often overshadowed by its intrinsically low sensitivity. Given that carbon makes up the backbone of most biologically relevant molecules, 13C NMR offers a straightforward measurement of these compounds. Two-dimensional 13C-13C 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 semi-automated approach called INETA (INADEQUATE network analysis) for the untargeted analysis of INADEQUATE datasets using an in silico INADEQUATE database. We demonstrate this approach using isotopically labeled Caenorhabditis elegans mixtures. PMID:25932900

  3. 14 N NMR of tetrapropylammonium based crystals

    NASA Astrophysics Data System (ADS)

    Dib, E.; Mineva, T.; Gaveau, P.; Alonso, B.

    2015-07-01

    We have investigated using 14N NMR different types of materials containing tetrapropylammonium cations. We consider the tetrapropylammonium bromide crystal as well as two different microporous materials silicalite-1 and AlPO-5, with MFI and AFI topology respectively, where the tetrapropylammonium cation plays the role of structure directing agent. 14N NMR quadrupolar coupling parameters were determined experimentally for all the crystals. In addition calculations based on Density Functional Theory with empirical dispersion (DFT-D) were performed on the MFI type zeolite. The sensitivity of the 14N quadrupolar coupling parameters to the spatial distribution of the anions in the zeolite's framework is emphasized.

  4. Magic Angle Spinning NMR of Viruses

    PubMed Central

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

    2015-01-01

    Viruses, relatively simple pathogens, are able to replicate in many living organisms and to adapt to various environments. Conventional atomic-resolution structural biology techniques, X-ray crystallography and solution NMR spectroscopy provided abundant information on the structures of individual proteins and nucleic acids comprising viruses; however, viral assemblies are not amenable to analysis by these techniques because of their large size, insolubility, and inherent lack of long-range order. In this article, we review the recent advances in magic angle spinning NMR spectroscopy that enabled atomic-resolution analysis of structure and dynamics of large viral systems and give examples of several exciting case studies. PMID:25919197

  5. Sensitive detection of NMR for thin films.

    PubMed

    Lee, Soonchil

    2015-10-01

    NMR can provide valuable information about thin films, but its relatively low sensitivity allows data acquisition only from bulk samples. The sensitivity problem is circumvented by detection schemes with higher sensitivity and/or enhanced polarization. In most of these ingenious techniques, electrons play a central role through hyperfine interactions with the nuclei of interest or the conversion of the spin orientation to an electric charge. The state of the art in NMR is the control of a single nuclear spin state, the complete form of which is one of the ultimate goals of nanotechnology. PMID:26549846

  6. NMR investigation of the quantum pigeonhole effect

    NASA Astrophysics Data System (ADS)

    V. S., Anjusha; Hegde, Swathi S.; Mahesh, T. S.

    2016-02-01

    NMR quantum simulators have been used for studying various quantum phenomena. Here, using a four-qubit NMR quantum simulator, we investigate the recently postulated quantum pigeonhole effect. In this phenomenon, a set of three particles in a two-path interferometer often appears to be in such a superposition that no two particles can be assigned a single path, thus exhibiting the nonclassical behavior. In our experiments, quantum pigeons are emulated by three nuclear qubits whose states are probed jointly and noninvasively by an ancillary spin. The experimental results are in good agreement with quantum theoretical predictions.

  7. NMR Microscopy - Micron-Level Resolution.

    NASA Astrophysics Data System (ADS)

    Kwok, Wing-Chi Edmund

    1990-01-01

    Nuclear Magnetic Resonance Imaging (MRI) has been developed into a powerful and widely used diagnostic tool since the invention of techniques using linear magnetic field gradients in 1973. The variety of imaging contrasts obtainable in MRI, such as spin density, relaxation times and flow rate, gives MRI a significant advantage over other imaging techniques. For common diagnostic applications, image resolutions have been in the order of millimeters with slice thicknesses in centimeters. For many research applications, however, resolutions in the order of tens of microns or smaller are needed. NMR Imaging in these high resolution disciplines is known as NMR microscopy. Compared with conventional microscopy, NMR microscopy has the advantage of being non-invasive and non-destructive. The major obstacles of NMR microscopy are low signal-to-noise ratio and effects due to spin diffusion. To overcome these difficulties, more sensitive RF probes and very high magnetic field gradients have to be used. The most effective way to increase sensitivity is to build smaller probes. Microscope probes of different designs have been built and evaluated. Magnetic field gradient coils that can produce linear field gradients up to 450 Gauss/cm were also assembled. In addition, since microscope probes often employ remote capacitors for RF tuning, the associated signal loss in the transmission line was studied. Imaging experiments have been carried out in a 2.1 Tesla small bore superconducting magnet using the typical two-dimensional spin warp imaging technique. Images have been acquired for both biological and non-biological samples. The highest resolution was obtained in an image of a nerve bundle from the spinal cord of a racoon and has an in-plane resolution of 4 microns. These experiments have demonstrated the potential application of NMR microscopy to pathological research, nervous system study and non -destructive testings of materials. One way to further improve NMR microscopy is

  8. The Quiet Renaissance of Protein NMR

    PubMed Central

    Barrett, Paul J.; Chen, Jiang; Cho, Min-Kyu; Kim, Ji-Hun; Lu, Zhenwei; Mathew, Sijo; Peng, Dungeng; Song, Yuanli; Van Horn, Wade D.; Zhuang, Tiandi; Sönnichsen, Frank D.; Sanders, Charles R.

    2013-01-01

    From roughly 1985 through the start of the new millennium, the cutting edge of solution protein nuclear magnetic resonance (NMR) spectroscopy was to a significant extent driven by the aspiration to determine structures. Here we survey recent advances in protein NMR that herald a renaissance in which a number of its most important applications reflect the broad problem-solving capability displayed by this method during its classical era during the 1970s and early 80s. “Without receivers fitted and kept in order, the air may tingle and thrill with the message, but it will not reach my spirit and consciousness.” Mary Slessor, Calabar, circa 1910 PMID:23368985

  9. 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 (2ω 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 2ω0 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 2ω0 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.

  10. 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 μT. 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 μT 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.

  11. Solid-state NMR for bacterial biofilms

    NASA Astrophysics Data System (ADS)

    Reichhardt, Courtney; Cegelski, Lynette

    2014-04-01

    Bacteria associate with surfaces and one another by elaborating an extracellular matrix to encapsulate cells, creating communities termed biofilms. Biofilms are beneficial in some ecological niches, but also contribute to the pathogenesis of serious and chronic infectious diseases. New approaches and quantitative measurements are needed to define the composition and architecture of bacterial biofilms to help drive the development of strategies to interfere with biofilm assembly. Solid-state nuclear magnetic resonance (NMR) is uniquely suited to the examination of insoluble and complex macromolecular and whole-cell systems. This article highlights three examples that implement solid-state NMR to deliver insights into bacterial biofilm composition and changes in cell-wall composition as cells transition to the biofilm lifestyle. Most recently, solid-state NMR measurements provided a total accounting of the protein and polysaccharide components in the extracellular matrix of an Escherichia coli biofilm and transformed our qualitative descriptions of matrix composition into chemical parameters that permit quantitative comparisons among samples. We present additional data for whole biofilm samples (cells plus the extracellular matrix) that complement matrix-only analyses. The study of bacterial biofilms by solid-state NMR is an exciting avenue ripe with many opportunities and we close the article by articulating some outstanding questions and future directions in this area.

  12. Solid-state NMR imaging system

    SciTech Connect

    Gopalsami, N.; Dieckman, S.L.; Ellingson, W.A.

    1990-01-01

    An accessory 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.

  13. Structural Studies of Biological Solids Using NMR

    NASA Astrophysics Data System (ADS)

    Ramamoorthy, Ayyalusamy

    2011-03-01

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

  14. Advanced Laboratory NMR Spectrometer with Applications.

    ERIC Educational Resources Information Center

    Biscegli, Clovis; And Others

    1982-01-01

    A description is given of an inexpensive nuclear magnetic resonance (NMR) spectrometer suitable for use in advanced laboratory courses. Applications to the nondestructive analysis of the oil content in corn seeds and in monitoring the crystallization of polymers are presented. (SK)

  15. Solid-state NMR imaging system

    DOEpatents

    Gopalsami, Nachappa; Dieckman, Stephen L.; Ellingson, William A.

    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.

  16. Hyperpolarized NMR Probes for Biological Assays

    PubMed Central

    Meier, Sebastian; Jensen, Pernille R.; Karlsson, Magnus; Lerche, Mathilde H.

    2014-01-01

    During the last decade, the development of nuclear spin polarization enhanced (hyperpolarized) molecular probes has opened up new opportunities for studying the inner workings of living cells in real time. The hyperpolarized probes are produced ex situ, introduced into biological systems and detected with high sensitivity and contrast against background signals using high resolution NMR spectroscopy. A variety of natural, derivatized and designed hyperpolarized probes has emerged for diverse biological studies including assays of intracellular reaction progression, pathway kinetics, probe uptake and export, pH, redox state, reactive oxygen species, ion concentrations, drug efficacy or oncogenic signaling. These probes are readily used directly under natural conditions in biofluids and are often directly developed and optimized for cellular assays, thus leaving little doubt about their specificity and utility under biologically relevant conditions. Hyperpolarized molecular probes for biological NMR spectroscopy enable the unbiased detection of complex processes by virtue of the high spectral resolution, structural specificity and quantifiability of NMR signals. Here, we provide a survey of strategies used for the selection, design and use of hyperpolarized NMR probes in biological assays, and describe current limitations and developments. PMID:24441771

  17. A Primer of Fourier Transform NMR.

    ERIC Educational Resources Information Center

    Macomber, Roger S.

    1985-01-01

    Fourier transform nuclear magnetic resonance (NMR) is a new spectroscopic technique that is often omitted from undergraduate curricula because of lack of instructional materials. Therefore, information is provided to introduce students to the technique of data collection and transformation into the frequency domain. (JN)

  18. NMR analysis of a fluorocarbon copolymer

    SciTech Connect

    Smith, R.E.; Smith, C.H.

    1987-10-01

    Vinylidene fluoride (VF/sub 2/) can be copolymerized with chlorotrifluoroethylene (CTFE) in an aqueous emulsion using a peroxide chain initiator. The physical properties of the resulting fluorocarbon polymer depend on the ratio of VF/sub 2/ to CTFE and the randomness of the copolymerization. When CTFE and VF are polymerized in an approximately 3:1 mole ratio, the resulting polymer is soluble in acetone (and other solvents) at room temperature. Using proton and fluorine-19 NMR, the mole ratio of CTFE to VF/sub 2/, the emulsifier (perfluorodecanoate) concentration, and the randomness of copolymerization can be determined. A trifluorotoluene internal standard is added to a d/sub 6/-acetone solution of the fluoropolymer. Proton NMR is used to determine the amount of VF/sub 2/. Fluorine-19 NMR is used to measure the amount of emulsifier and the randomness of copolymerization. Each analysis requires about 5 minutes, and is quite precise, with relative standard deviations from 3 to 10% (10 replicates analyzed). In addition, the results from NMR analyses agree well with wet chemical analyses. 4 refs., 3 figs., 3 tabs.

  19. Increasing the quantitative bandwidth of NMR measurements.

    PubMed

    Power, J E; Foroozandeh, M; Adams, R W; Nilsson, M; Coombes, S R; Phillips, A R; Morris, G A

    2016-02-18

    The frequency range of quantitative NMR is increased from tens to hundreds of kHz by a new pulse sequence, CHORUS. It uses chirp pulses to excite uniformly over very large bandwidths, yielding accurate integrals even for nuclei such as (19)F that have very wide spectra. PMID:26789115

  20. Combining solid-state NMR spectroscopy with first-principles calculations - a guide to NMR crystallography.

    PubMed

    Ashbrook, Sharon E; McKay, David

    2016-06-01

    Recent advances in the application of first-principles calculations of NMR parameters to periodic systems have resulted in widespread interest in their use to support experimental measurement. Such calculations often play an important role in the emerging field of "NMR crystallography", where NMR spectroscopy is combined with techniques such as diffraction, to aid structure determination. Here, we discuss the current state-of-the-art for combining experiment and calculation in NMR spectroscopy, considering the basic theory behind the computational approaches and their practical application. We consider the issues associated with geometry optimisation and how the effects of temperature may be included in the calculation. The automated prediction of structural candidates and the treatment of disordered and dynamic solids are discussed. Finally, we consider the areas where further development is needed in this field and its potential future impact. PMID:27117884

  1. 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

  2. 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.

  3. 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...

  4. Solid-state NMR studies of supercapacitors.

    PubMed

    Griffin, John M; Forse, Alexander C; Grey, Clare P

    2016-01-01

    Electrochemical double-layer capacitors, or 'supercapacitors' are attracting increasing attention as high-power energy storage devices for a wide range of technological applications. These devices store charge through electrostatic interactions between liquid electrolyte ions and the surfaces of porous carbon electrodes. However, many aspects of the fundamental mechanism of supercapacitance are still not well understood, and there is a lack of experimental techniques which are capable of studying working devices. Recently, solid-state NMR has emerged as a powerful tool for studying the local environments and behaviour of electrolyte ions in supercapacitor electrodes. In this Trends article, we review these recent developments and applications. We first discuss the basic principles underlying the mechanism of supercapacitance, as well as the key NMR observables that are relevant to the study of supercapacitor electrodes. We then review some practical aspects of the study of working devices using ex situ and in situ methodologies and explain the key advances that these techniques have allowed on the study of supercapacitor charging mechanisms. NMR experiments have revealed that the pores of the carbon electrodes contain a significant number of electrolyte ions in the absence of any charging potential. This has important implications for the molecular mechanisms of supercapacitance, as charge can be stored by different ion adsorption/desorption processes. Crucially, we show how in situ NMR experiments can be used to quantitatively study and characterise the charging mechanism, with the experiments providing the most detailed picture of charge storage to date, offering the opportunity to design enhanced devices. Finally, an outlook for future directions for solid-state NMR in supercapacitor research is offered. PMID:26974032

  5. OPENCORE NMR: open-source core modules for implementing an integrated FPGA-based NMR spectrometer.

    PubMed

    Takeda, Kazuyuki

    2008-06-01

    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. Inside the FPGA chip have been implemented a number of digital modules including three pulse programmers, the digital part of DDS, a digital quadrature demodulator, dual digital low-pass filters, and a PC interface. These FPGA core modules are written in VHDL, and their source codes are available on our website. This work aims at providing sufficient information with which one can, given some facility in circuit board manufacturing, reproduce the OPENCORE NMR spectrometer presented here. Also, the users are encouraged to modify the design of spectrometer according to their own specific needs. A home-built NMR spectrometer can serve complementary roles to a sophisticated commercial spectrometer, should one comes across such new ideas that require heavy modification to hardware inside the spectrometer. This work can lower the barrier of building a handmade NMR spectrometer in the laboratory, and promote novel and exciting NMR experiments. PMID:18374613

  6. NMR Constraints Analyser: a web-server for the graphical analysis of NMR experimental constraints.

    PubMed

    Heller, Davide Martin; Giorgetti, Alejandro

    2010-07-01

    Nuclear magnetic resonance (NMR) spectroscopy together with X-ray crystallography, are the main techniques used for the determination of high-resolution 3D structures of biological molecules. The output of an NMR experiment includes a set of lower and upper limits for the distances (constraints) between pairs of atoms. If the number of constraints is high enough, there will be a finite number of possible conformations (models) of the macromolecule satisfying the data. Thus, the more constraints are measured, the better defined these structures will be. The availability of a user-friendly tool able to help in the analysis and interpretation of the number of experimental constraints per residue, is thus of valuable importance when assessing the levels of structure definition of NMR solved biological macromolecules, in particular, when high-quality structures are needed in techniques such as, computational biology approaches, site-directed mutagenesis experiments and/or drug design. Here, we present a free publicly available web-server, i.e. NMR Constraints Analyser, which is aimed at providing an automatic graphical analysis of the NMR experimental constraints atom by atom. The NMR Constraints Analyser server is available from the web-page http://molsim.sci.univr.it/constraint. PMID:20513646

  7. Squid detected NMR and MRI at ultralow fields

    SciTech Connect

    Clarke, John; McDermott, Robert; Pines, Alexander; Trabesinger, Andreas Heinz

    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.

  8. Squid detected NMR and MRI at ultralow fields

    DOEpatents

    Clarke, John; McDermott, Robert; Pines, Alexander; Trabesinger, Andreas Heinz

    2006-05-30

    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.

  9. SQUID detected NMR and MRI at ultralow fields

    DOEpatents

    Clarke, John; McDermott, Robert; Pines, Alexander; Trabesinger, Andreas Heinz

    2006-10-03

    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.

  10. Squid detected NMR and MRI at ultralow fields

    SciTech Connect

    Clarke, John; Pines, Alexander; McDermott, Robert F.; Trabesinger, Andreas H.

    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. 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

  12. Multiple effects of glycerol on plant cell metabolism. Phosphorus-31 nuclear magnetic resonance studies.

    PubMed

    Aubert, S; Gout, E; Bligny, R; Douce, R

    1994-08-26

    The effects of glycerol on plant cell metabolism were studied with sycamore (Acer pseudoplatanus L.) cells using 31P nuclear magnetic resonance spectroscopy. After a long period of sucrose starvation, the addition of 50 mM glycerol to the medium did not restore the original glucose-6-P pool and led to a rapid accumulation of sn-glycerol-3-P in the cytoplasmic compartment. The synthesis of sn-glycerol-3-P was rapid and occurred first at the expense of cytoplasmic P(i). Accumulated sn-glycerol-3-P competitively inhibited glucose-6-phosphate isomerase activity when fructose-6-P was the varied substrate. Such a situation prevented the rapid recycling of triose phosphates back to hexose phosphates and led to an arrest of the functioning of the cytosolic and plastidial pentose phosphate pathways. Under these conditions, the flow of carbon to drive cell respiration derived almost exclusively from glycerol, and this polyalcohol was not used as a source of carbon skeletons for biosynthesis. Glycerol also induced the accumulation of O-phosphohomoserine in the cytoplasmic compartment as long as the cell culture medium contained sucrose. Finally glycerol added to sucrose-starved cells stopped the accumulation of phosphocholine (Roby, C., Martin J.-B., Bligny, R., and Douce, R. (1987) J. Biol. Chem. 262, 5000-5007) and prevented a further decline in the uncoupled rate of O2 consumption by the cells (Journet, E. P., Bligny, R., and Douce, R. (1986) J. Biol. Chem. 261, 3193-3199). These last observations strongly suggest that glycerol prevented the triggering of autophagy induced by sucrose starvation in sycamore cells. PMID:8063774

  13. 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 β-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 → β-sheet-like → β-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 β-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.

  14. 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.

  15. NMR shielding calculations across the periodic table: diamagnetic uranium compounds. 2. Ligand and metal NMR.

    PubMed

    Schreckenbach, Georg

    2002-12-16

    In this and a previous article (J. Phys. Chem. A 2000, 104, 8244), the range of application for relativistic density functional theory (DFT) is extended to the calculation of nuclear magnetic resonance (NMR) shieldings and chemical shifts in diamagnetic actinide compounds. Two relativistic DFT methods are used, ZORA ("zeroth-order regular approximation") and the quasirelativistic (QR) method. In the given second paper, NMR shieldings and chemical shifts are calculated and discussed for a wide range of compounds. The molecules studied comprise uranyl complexes, [UO(2)L(n)](+/-)(q); UF(6); inorganic UF(6) derivatives, UF(6-n)Cl(n), n = 0-6; and organometallic UF(6) derivatives, UF(6-n)(OCH(3))(n), n = 0-5. Uranyl complexes include [UO(2)F(4)](2-), [UO(2)Cl(4)](2-), [UO(2)(OH)(4)](2-), [UO(2)(CO(3))(3)](4-), and [UO(2)(H(2)O)(5)](2+). For the ligand NMR, moderate (e.g., (19)F NMR chemical shifts in UF(6-n)Cl(n)) to excellent agreement [e.g., (19)F chemical shift tensor in UF(6) or (1)H NMR in UF(6-n)(OCH(3))(n)] has been found between theory and experiment. The methods have been used to calculate the experimentally unknown (235)U NMR chemical shifts. A large chemical shift range of at least 21,000 ppm has been predicted for the (235)U nucleus. ZORA spin-orbit appears to be the most accurate method for predicting actinide metal chemical shifts. Trends in the (235)U NMR chemical shifts of UF(6-n)L(n) molecules are analyzed and explained in terms of the calculated electronic structure. It is argued that the energy separation and interaction between occupied and virtual orbitals with f-character are the determining factors. PMID:12470051

  16. Nuclear spin noise in NMR revisited

    NASA Astrophysics Data System (ADS)

    Ferrand, Guillaume; Huber, Gaspard; Luong, Michel; Desvaux, Hervé

    2015-09-01

    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 comparisons 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.

  17. Multifunctional pulse sequence generator for pulse NMR

    NASA Astrophysics Data System (ADS)

    Wang, Dongsheng

    1988-06-01

    A new multifunctional pulse sequence generator has been designed and constructed. It can conveniently generate various pulse sequences used in nuclear-magnetic resonance (NMR) to measure the spin-lattice relaxation time T1, the spin-spin relaxation time T2, and the spin-locking relaxation time T1 ρ. It can also be used in pulse Fourier transform NMR and double resonance. The intervals of pulses can increase automatically with sequence repetitions and the generator can be used in two-dimensional spectrum measurement and spin-density imaging research. The sequences can be generated through four different triggering methods and there are two synchronous pulse outputs and fifteen auxiliary pulse outputs, so the generator can be conveniently interfaced with a computer or other instruments. The circuitry, functions, and features of the generator are described in this article.

  18. 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.

  19. 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

  20. NMR with excitation modulated by Frank sequences.

    PubMed

    Blümich, Bernhard; Gong, Qingxia; Byrne, Eimear; Greferath, Marcus

    2009-07-01

    Miniaturized NMR is of growing importance in bio-, chemical, and -material sciences. Other than the magnet, bulky components are the radio-frequency power amplifier and the power supply or battery pack. We show that constant flip-angle excitation with phase modulation following a particular type of polyphase perfect sequences results in low peak excitation power at high response peak power. It has ideal power distribution in both the time domain and the frequency domain. A savings in peak excitation power of six orders of magnitude has been realized compared to conventionally pulsed excitation. Among others, the excitation promises to be of use for button-cell operated miniature NMR devices as well as for complying with specific-absorption-rate regulations in high-field medical imaging. PMID:19386525

  1. NMR-based diffusion lattice imaging.

    PubMed

    Laun, Frederik Bernd; Müller, Lars; Kuder, Tristan Anselm

    2016-03-01

    Nuclear magnetic resonance (NMR) diffusion experiments are widely employed as they yield information about structures hindering the diffusion process, e.g., about cell membranes. While it has been shown in recent articles that these experiments can be used to determine the shape of closed pores averaged over a volume of interest, it is still an open question how much information can be gained in open well-connected systems. In this theoretical work, it is shown that the full structure information of connected periodic systems is accessible. To this end, the so-called "SEquential Rephasing by Pulsed field-gradient Encoding N Time intervals" (SERPENT) sequence is used, which employs several diffusion encoding gradient pulses with different amplitudes. Two two-dimensional solid matrices that are surrounded by an NMR-visible medium are considered: a hexagonal lattice of cylinders and a rectangular lattice of isosceles triangles. PMID:27078384

  2. Nuclear spin noise in NMR revisited

    SciTech Connect

    Ferrand, Guillaume; Luong, Michel

    2015-09-07

    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 comparisons 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.

  3. NMR studies of nucleic acid dynamics

    NASA Astrophysics Data System (ADS)

    Al-Hashimi, Hashim M.

    2013-12-01

    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.

  4. NMR spectral analysis using prior knowledge

    NASA Astrophysics Data System (ADS)

    Kasai, Takuma; Nagata, Kenji; Okada, Masato; Kigawa, Takanori

    2016-03-01

    Signal assignment is a fundamental step for analyses of protein structure and dynamics with nuclear magnetic resonance (NMR). Main-chain signal assignment is achieved with a sequential assignment method and/or an amino-acid selective stable isotope labeling (AASIL) method. Combinatorial selective labeling (CSL) methods, as well as our labeling strategy, stable isotope encoding (SiCode), were developed to reduce the required number of labeled samples, since one of the drawbacks of AASIL is that many samples are needed. Signal overlapping in NMR spectra interferes with amino-acid determination by CSL and SiCode. Since spectral deconvolution by peak fitting with a gradient method cannot resolve closely overlapped signals, we developed a new method to perform both peak fitting and amino acid determination simultaneously, with a replica exchange Monte Carlo method, incorporating prior knowledge of stable-isotope labeling ratios and the amino-acid sequence of the protein.

  5. NMR-based diffusion lattice imaging

    NASA Astrophysics Data System (ADS)

    Laun, Frederik Bernd; Müller, Lars; Kuder, Tristan Anselm

    2016-03-01

    Nuclear magnetic resonance (NMR) diffusion experiments are widely employed as they yield information about structures hindering the diffusion process, e.g., about cell membranes. While it has been shown in recent articles that these experiments can be used to determine the shape of closed pores averaged over a volume of interest, it is still an open question how much information can be gained in open well-connected systems. In this theoretical work, it is shown that the full structure information of connected periodic systems is accessible. To this end, the so-called "SEquential Rephasing by Pulsed field-gradient Encoding N Time intervals" (SERPENT) sequence is used, which employs several diffusion encoding gradient pulses with different amplitudes. Two two-dimensional solid matrices that are surrounded by an NMR-visible medium are considered: a hexagonal lattice of cylinders and a rectangular lattice of isosceles triangles.

  6. Theory of NMR in Superconducting Multilayers

    NASA Astrophysics Data System (ADS)

    Kuboki, Kazuhiro; Fukuyama, Hidetoshi

    1988-09-01

    Motivated by experiments of NMR on superconductor(S)-normal-metal(N) multi-layer system, we have calculated the nuclear spin-lattice relaxation rate, T1-1, for both N and S layers based on the bilayer model of McMillan for the proximity effect. The results of calculation are in essential agreement with experiments by Aoki et al. and Imai et al.

  7. Theory of NMR for superconducting superlattices

    NASA Astrophysics Data System (ADS)

    Kuboki, Kazuhiro; Fukuyama, Hidetoshi

    1988-06-01

    Motivated by experiments of NMR on superconductor(S)-normal-metal(N) multilayer system, we have calculated the nuclear spin-lattice relaxation rate,T1-1, for both N and S metals based on the bilayer model of McMillan for the proximity effect. The results of calculations are in essential agreement with experiments by Aoki et al. and Imai et al.

  8. 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.

  9. Quantitative calibration of radiofrequency NMR Stark effects

    NASA Astrophysics Data System (ADS)

    Tarasek, Matthew R.; Kempf, James G.

    2011-10-01

    Nuclear magnetic resonance (NMR) Stark responses can occur in quadrupolar nuclei for an electric field oscillating at twice the usual NMR frequency (2ω0). Calibration of responses to an applied E field is needed to establish nuclear spins as probes of native E fields within material and molecular systems. We present an improved approach and apparatus for accurate measurement of quadrupolar Stark effects. Updated values of C14 (the response parameter in cubic crystals) were obtained for both 69Ga and 75As in GaAs. Keys to improvement include a modified implementation of voltage dividers to assess the 2ω0 amplitude, |E|, and the stabilization of divider response by reduction of stray couplings in 2ω0 circuitry. Finally, accuracy was enhanced by filtering sets of |E| through a linear response function that we established for the radiofrequency amplifier. Our approach is verified by two types of spectral results. Steady-state 2ω0 excitation to presaturate NMR spectra yielded C14 = (2.59 ± 0.06) × 1012 m-1 for 69Ga at room-temperature and 14.1 T. For 75As, we obtained (3.1 ± 0.1) × 1012 m-1. Both values reconcile with earlier results from 77 K and below 1 T, whereas current experiments are at room temperature and 14.1 T. Finally, we present results where few-microsecond pulses of the 2ω0 field induced small (tens of Hz) changes in high-resolution NMR line shapes. There too, spectra collected vs |E| agree with the model for response, further establishing the validity of our protocols to specify |E|.

  10. Multiple-quantum NMR in solids

    NASA Astrophysics Data System (ADS)

    Yen, Yu-Sze; Pines, A.

    1983-03-01

    Multiple-quantum NMR has typically been observed in small groups of spins in isolated molecules. Due to the profusion of spin transitions in a solid, individual lines are unresolved. Excitation of high quantum transitions by normal schemes is thus difficult. To ensure that overlapping lines add constructively and to enhance sensitivity, time-reversal pulse sequences are used to generate all lines in phase. Up to 22-quantum 1H absorption in solid adamantane is observed.

  11. Multiple-quantum NMR in solids

    SciTech Connect

    Yen, Y.; Pines, A.

    1983-03-15

    Multiple-quantum NMR has typically been observed in small groups of spins in isolated molecules. Due to the profusion of spin transitions in a solid, individual lines are unresolved. Excitation of high quantum transitions by normal schemes is thus difficult. To ensure that overlapping lines add constructively and 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.

  12. Statistical filtering for NMR based structure generation

    PubMed Central

    2011-01-01

    The constitutional assignment of natural products by NMR spectroscopy is usually based on 2D NMR experiments like COSY, HSQC, and HMBC. The difficulty of a structure elucidation problem depends more on the type of the investigated molecule than on its size. Saturated compounds can usually be assigned unambiguously by hand using only COSY and 13C-HMBC data, whereas condensed heterocycles are problematic due to their lack of protons that could show interatomic connectivities. Different computer programs were developed to aid in the structural assignment process, one of them COCON. In the case of unsaturated and substituted molecules structure generators frequently will generate a very large number of possible solutions. This article presents a "statistical filter" for the reduction of the number of results. The filter works by generating 3D conformations using smi23d, a simple MD approach. All molecules for which the generation of constitutional restraints failed were eliminated from the result set. Some structural elements removed by the statistical filter were analyzed and checked against Beilstein. The automatic removal of molecules for which no MD parameter set could be created was included into WEBCOCON. The effect of this filter varies in dependence of the NMR data set used, but in no case the correct constitution was removed from the resulting set. PMID:21835037

  13. NMR methodologies for studying mitochondrial bioenergetics.

    PubMed

    Alves, Tiago C; Jarak, Ivana; Carvalho, Rui A

    2012-01-01

    Nuclear magnetic resonance (NMR) spectroscopy is a technique with an increasing importance in the study of metabolic diseases. Its initial important role in the determination of chemical structures (1, 2) has been considerably overcome by its potential for the in vivo study of metabolism (3-5). The main characteristic that makes this technique so attractive is its noninvasiveness. Only nuclei capable of transitioning between energy states, in the presence of an intense and constant magnetic field, are studied. This includes abundant nuclei such as proton ((1)H) and phosphorous ((31)P), as well as stable isotopes such as deuterium ((2)H) and carbon 13 ((13)C). This allows a wide range of applications that vary from the determination of water distribution in tissues (as obtained in a magnetic resonance imaging scan) to the calculation of metabolic fluxes under ex vivo and in vivo conditions without the need to use radioactive tracers or tissue biopsies (as in a magnetic resonance spectroscopy (MRS) scan). In this chapter, some technical aspects of the methodology of an NMR/MRS experiment as well as how it can be used to study mitochondrial bioenergetics are overviewed. Advantages and disadvantages of in vivo MRS versus high-resolution NMR using proton high rotation magic angle spinning (HRMAS) of tissue biopsies and tissue extracts are also discussed. PMID:22057574

  14. Sol-gel kinetics by NMR

    SciTech Connect

    Assink, R.A.; Kay, B.D.

    1991-01-01

    The chemical synthesis of advanced ceramic and glass materials by the sol-gel process has become an area of increasing activity in the field of material science. The sol-gel process provides a means to prepare homogeneous, high purity materials with tailored chemical and physical properties. This paper surveyed the nuclear magnetic resonance (NMR) studies of silicon-based sol-gel kinetics. A review of the various models which have been used to analyze the chemical kinetics of various sol-gel systems was presented. The utility of NMR spectroscopy was demonstrated in investigating the influence that various reaction conditions have on the reaction pathways by which sol-gel derived materials are synthesized. By observing in a direct fashion the chemical pathway of the sol-gel, it is often possible to relate the final properties of the material to the formulation and reaction conditions of the sol-gel. The study of reaction kinetics by NMR is expected to play an increasingly important role in understanding sol-gel processing and material properties. 15 refs. (DP)

  15. DFT and NMR parameterized conformation of valeranone.

    PubMed

    Torres-Valencia, J Martín; Meléndez-Rodríguez, Myriam; Alvarez-García, Rocío; Cerda-García-Rojas, Carlos M; Joseph-Nathan, Pedro

    2004-10-01

    A Monte Carlo random search using molecular mechanics, followed by geometry optimization of each minimum energy structure employing density functional theory (DFT) calculations at the B3LYP/6-31G* level and a Boltzmann analysis of the total energies, generated accurate molecular models which describe the conformational behavior of the antispasmodic bicyclic sesquiterpene valeranone (1). The theoretical H-C-C-H dihedral angles gave the corresponding 1H, 1H vicinal coupling constants using a generalized Karplus-type equation. In turn, the 3J(H,H) values were used as initial input data for the spectral simulation of 1, which after iteration provided an excellent correlation with the experimental 1H NMR spectrum. The calculated 3J(H,H) values closely predicted the experimental values, excepting the coupling constant between the axial hydrogen alpha to the carbonyl group and the equatorial hydrogen beta to the carbonyl group (J(2beta, 3beta)). The difference is explained in terms of the electron density distribution found in the highest occupied molecular orbital (HOMO) of 1. The simulated spectrum, together with 2D NMR experiments, allowed the total assignment of the 1H and 13C NMR spectra of 1. PMID:15366065

  16. Nonclassical correlation in NMR quadrupolar systems

    SciTech Connect

    Soares-Pinto, D. O.; Auccaise, R.; Azevedo, E. R. de; Bonagamba, T. J.; Celeri, L. C.; Maziero, J.; Serra, R. M.; Fanchini, F. F.

    2010-06-15

    The existence of quantum correlation (as revealed by quantum discord), other than entanglement and its role in quantum-information processing (QIP), is a current subject for discussion. In particular, it has been suggested that this nonclassical correlation may provide computational speedup for some quantum algorithms. In this regard, bulk nuclear magnetic resonance (NMR) has been successfully used as a test bench for many QIP implementations, although it has also been continuously criticized for not presenting entanglement in most of the systems used so far. In this paper, we report a theoretical and experimental study on the dynamics of quantum and classical correlations in an NMR quadrupolar system. We present a method for computing the correlations from experimental NMR deviation-density matrices and show that, given the action of the nuclear-spin environment, the relaxation produces a monotonic time decay in the correlations. Although the experimental realizations were performed in a specific quadrupolar system, the main results presented here can be applied to whichever system uses a deviation-density matrix formalism.

  17. 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 60μm yields on the order of 500cm(2) of solid-supported single bilayer surface, sufficient for NMR studies. The tubular bilayers are free of detergent, fully hydrated, and accessible for ligands from one side of the membrane. The use of AAO filters greatly improves reproducibility of the reconstitution process such that the influence of protein on lipid order parameters can be studied with high resolution. As an example, results for the G protein-coupled receptor of class A, bovine rhodopsin, are shown. By (2)H NMR order parameter measurements, it is detected that rhodopsin insertion elastically deforms membranes near the protein. Furthermore, by (1)H saturation-transfer NMR under conditions of magic angle spinning, we demonstrate detection of preferences in interactions of rhodopsin with particular lipid species. It is assumed that function of integral membrane proteins depends on both protein-induced elastic deformations of the lipid matrix and preferences for interaction of the protein with particular lipid species in the first layer of lipids surrounding the protein. PMID:23374188

  18. NMR quantitation: influence of RF inhomogeneity

    PubMed Central

    Mo, Huaping; Harwood, John; Raftery, Daniel

    2016-01-01

    The NMR peak integral is ideally linearly dependent on the sine of excitation angle (θ), 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 θ. To evaluate the impact quantitatively, we introduce a RF inhomogeneity factor I(θ) as a function of the nominal pulse excitation angle and propose a simple calibration procedure. Alternatively, I(θ) 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(θ), 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(θ) 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

  19. Earth's field NMR; a surface moisture detector?

    NASA Astrophysics Data System (ADS)

    Fukushima, Eiichi; Altobelli, Stephen; McDowell, Andrew; Zhang, Tongsheng

    2012-10-01

    Earth's field NMR (EFNMR), being free of magnets, would be an ideal teaching medium as well as a mobile NMR technique except for its weak S/N. The common EFNMR apparatus uses a powerful prepolarization field to enhance the spin magnetization before the experiment. We introduce a coil design geared to larger but manageable samples with sufficient sensitivity without prepolarization to move EFNMR closer to routine use and to provide an inexpensive teaching tool. Our coil consists of parallel wires spread out on a plywood to form a current sheet with the current return wires separated so they will not influence the main part of the coil assembly. The sensitive region is a relatively thin region parallel to the coil and close to it. A single turn of the coil is wound to be topologically equivalent to a figure-8. The two crossing segments in the center of a figure-8 form two of the parallel wires of the flat coil. Thus, a two-turn figure-8 has four crossing wires so its topologically equivalent coil will have four parallel wires with currents in phase. Together with the excellent sensitivity, this coil offers outstanding interference rejection because of the figure-8 geometry. An example of such a coil has 328 parallel wires covering a ˜1 meter square plywood which yields a good NMR signal from 26 liters of water spread out roughly over the area of the coil in less than one minute in a nearby park.

  20. NMR Studies of Dynamic Biomolecular Conformational Ensembles

    PubMed Central

    Torchia, Dennis A.

    2015-01-01

    Multidimensional heteronuclear NMR approaches can provide nearly complete sequential signal assignments of isotopically enriched biomolecules. The availability of assignments together with measurements of spin relaxation rates, residual spin interactions, J-couplings and chemical shifts provides information at atomic resolution about internal dynamics on timescales ranging from ps to ms, both in solution and in the solid state. However, due to the complexity of biomolecules, it is not possible to extract a unique atomic-resolution description of biomolecular motions even from extensive NMR data when many conformations are sampled on multiple timescales. For this reason, powerful computational approaches are increasingly applied to large NMR data sets to elucidate conformational ensembles sampled by biomolecules. In the past decade, considerable attention has been directed at an important class of biomolecules that function by binding to a wide variety of target molecules. Questions of current interest are: “Does the free biomolecule sample a conformational ensemble that encompasses the conformations found when it binds to various targets; and if so, on what time scale is the ensemble sampled?” This article reviews recent efforts to answer these questions, with a focus on comparing ensembles obtained for the same biomolecules by different investigators. A detailed comparison of results obtained is provided for three biomolecules: ubiquitin, calmodulin and the HIV-1 trans-activation response RNA. PMID:25669739

  1. Discrete analysis of stochastic NMR.II

    NASA Astrophysics Data System (ADS)

    Wong, S. T. S.; Rods, M. S.; Newmark, R. D.; Budinger, T. F.

    Stochastic NMR is an efficient technique for high-field in vivo imaging and spectroscopic studies where the peak RF power required may be prohibitively high for conventional pulsed NMR techniques. A stochastic NMR experiment excites the spin system with a sequence of RF pulses where the flip angles or the phases of the pulses are samples of a discrete stochastic process. In a previous paper the stochastic experiment was analyzed and analytic expressions for the input-output cross-correlations, average signal power, and signal spectral density were obtained for a general stochastic RF excitation. In this paper specific cases of excitation with random phase, fixed flip angle, and excitation with two random components in quadrature are analyzed. The input-output cross-correlation for these two types of excitations is shown to be Lorentzian. Line broadening is the only spectral distortion as the RF excitation power is increased. The systematic noise power is inversely proportional to the number of data points N used in the spectral reconstruction. The use of a complete maximum length sequence (MLS) may improve the signal-to-systematic-noise ratio by 20 dB relative to random binary excitation, but peculiar features in the higher-order autocorrelations of MLS cause noise-like distortion in the reconstructed spectra when the excitation power is high. The amount of noise-like distortion depends on the choice of the MLS generator.

  2. Guiding automated NMR structure determination using a global optimization metric, the NMR DP score.

    PubMed

    Huang, Yuanpeng Janet; Mao, Binchen; Xu, Fei; Montelione, Gaetano T

    2015-08-01

    ASDP is an automated NMR NOE assignment program. It uses a distinct bottom-up topology-constrained network anchoring approach for NOE interpretation, with 2D, 3D and/or 4D NOESY peak lists and resonance assignments as input, and generates unambiguous NOE constraints for iterative structure calculations. ASDP is designed to function interactively with various structure determination programs that use distance restraints to generate molecular models. In the CASD-NMR project, ASDP was tested and further developed using blinded NMR data, including resonance assignments, either raw or manually-curated (refined) NOESY peak list data, and in some cases (15)N-(1)H residual dipolar coupling data. In these blinded tests, in which the reference structure was not available until after structures were generated, the fully-automated ASDP program performed very well on all targets using both the raw and refined NOESY peak list data. Improvements of ASDP relative to its predecessor program for automated NOESY peak assignments, AutoStructure, were driven by challenges provided by these CASD-NMR data. These algorithmic improvements include (1) using a global metric of structural accuracy, the discriminating power score, for guiding model selection during the iterative NOE interpretation process, and (2) identifying incorrect NOESY cross peak assignments caused by errors in the NMR resonance assignment list. These improvements provide a more robust automated NOESY analysis program, ASDP, with the unique capability of being utilized with alternative structure generation and refinement programs including CYANA, CNS, and/or Rosetta. PMID:26081575

  3. Calibration of NMR well logs from carbonate reservoirs with laboratory NMR measurements and μXRCT

    DOE PAGESBeta

    Mason, Harris E.; Smith, Megan M.; Hao, Yue; Carroll, Susan A.

    2014-12-31

    The use of nuclear magnetic resonance (NMR) well log data has the potential to provide in-situ porosity, pore size distributions, and permeability of target carbonate CO₂ storage reservoirs. However, these methods which have been successfully applied to sandstones have yet to be completely validated for carbonate reservoirs. Here, we have taken an approach to validate NMR measurements of carbonate rock cores with independent measurements of permeability and pore surface area to volume (S/V) distributions using differential pressure measurements and micro X-ray computed tomography (μXRCT) imaging methods, respectively. We observe that using standard methods for determining permeability from NMR data incorrectlymore » predicts these values by orders of magnitude. However, we do observe promise that NMR measurements provide reasonable estimates of pore S/V distributions, and with further independent measurements of the carbonate rock properties that universally applicable relationships between NMR measured properties may be developed for in-situ well logging applications of carbonate reservoirs.« less

  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)

    Doğan, N.; Topkaya, R.; Subaşi, 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. NMR spectroscopy of experimentally shocked single crystal quartz: A reexamination of the NMR shock barometer

    NASA Technical Reports Server (NTRS)

    Fiske, P. S.; Gratz, A. J.; Nellis, W. J.

    1993-01-01

    Cygan and others report a broadening of the Si-29 nuclear magnetic resonance (NMR) peak for synthetic quartz powders with increasing shock pressure which they propose as a shock wave barometer for natural systems. These results are expanded by studying single crystal quartz shocked to 12 and 33 GPa using the 6.5 m two-stage light-gas gun at Lawrence Livermore National Laboratories. Our NMR results differ substantially from those of Cygan and others and suggest that the proposed shock wave barometer may require refinement. The difference in results between this study and that of Cygan and others is most likely caused by different starting materials (single crystal vs. powder) and different shock loading histories. NMR results from single crystal studies may be more applicable to natural systems.

  7. 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

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

    NASA Astrophysics Data System (ADS)

    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-13C, U-15N]-labeled proteins. Given the sequence of the protein and data for the orthogonal 2D 1H-15N and 1H-13C 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 1H, 13C, and 15N 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.

  9. NMR Wool Tube: a novel method for NMR solution analysis of derivatized glass surfaces.

    PubMed

    Cholewa, Olivia Maria

    2004-08-13

    Glass wool was placed within an NMR tube as a solid support for the covalent attachment of a molecule to allow for a simple one-dimensional 1H FT NMR solution analysis. This novel procedure avoids the use of expensive sample tubes or platforms, as required for magic angle or fast spinning, exotic pulse sequences, isotopic labeling or the use of a large number of scans to provide the ability to analyze the structure, mobility, ligand binding, and solvent interactions of the surface bound molecule. PMID:15387199

  10. Isotope labeling for NMR studies of macromolecular structure and interactions

    SciTech Connect

    Wright, P.E.

    1994-12-01

    Implementation of biosynthetic methods for uniform or specific isotope labeling of proteins, coupled with the recent development of powerful heteronuclear multidimensional NMR methods, has led to a dramatic increase in the size and complexity of macromolecular systems that are now amenable to NMR structural analysis. In recent years, a new technology has emerged that combines uniform {sup 13}C, {sup 15}N labeling with heteronuclear multidimensional NMR methods to allow NMR structural studies of systems approaching 25 to 30 kDa in molecular weight. In addition, with the introduction of specific {sup 13}C and {sup 15}N labels into ligands, meaningful NMR studies of complexes of even higher molecular weight have become feasible. These advances usher in a new era in which the earlier, rather stringent molecular weight limitations have been greatly surpassed and NMR can begin to address many central biological problems that involve macromolecular structure, dynamics, and interactions.

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

    NASA Astrophysics Data System (ADS)

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

    1988-01-01

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

  12. 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.

  13. 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

  14. 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.

  15. Rotational Doppler Effect and Barnett Field in Spinning NMR

    NASA Astrophysics Data System (ADS)

    Chudo, Hiroyuki; Harii, Kazuya; Matsuo, Mamoru; Ieda, Jun'ichi; Ono, Masao; Maekawa, Sadamichi; Saitoh, Eiji

    2015-04-01

    We report the observation of the rotational Doppler effect using nuclear magnetic resonance (NMR). We have developed a coil-spinning technique that enables measurements by rotating a detector and fixing a sample. We found that the rotational Doppler effect gives rise to NMR frequency shifts equal to the rotation frequency. We formulate the rotational Doppler effect and the Barnett field using a vector model for the nuclear magnetic moment. This formulation reveals that, with just the sample rotating, both effects cancel each other, thereby explaining the absence of an NMR frequency shift in conventional sample-spinning NMR measurements.

  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. Measurement of vorticity diffusion by NMR microscopy.

    PubMed

    Brown, Jennifer R; Callaghan, Paul T

    2010-05-01

    In a Newtonian fluid, vorticity diffuses at a rate determined by the kinematic viscosity. Here we use rapid NMR velocimetry, based on a RARE sequence, to image the time-dependent velocity field on startup of a fluid-filled cylinder and therefore measure the diffusion of vorticity. The results are consistent with the solution to the vorticity diffusion equation where the angular velocity on the outside surface of the fluid, at the cylinder's rotating wall, is fixed. This method is a means of measuring kinematic viscosity for low viscosity fluids without the need to measure stress. PMID:20189854

  18. Analysis of multiple pulse NMR in solids

    NASA Technical Reports Server (NTRS)

    Rhim, W.-K.; Elleman, D. D.; Vaughan, R. W.

    1973-01-01

    The general problems associated with the removal of the effects of dipolar broadening from solid-state NMR spectra are analyzed. The effects of finite pulse width and H sub 1 inhomogeneity are shown to have limited the resolution of previous pulse cycles, and a new eight-pulse cycle designed to minimize these problems is discussed. Spectra for F-19 in CaF2 taken with this cycle are presented which show residual linewidth near 10 Hz. The feasibility of measuring proton chemical shift tensors is discussed.

  19. Quenched Hydrogen Exchange NMR of Amyloid Fibrils.

    PubMed

    Alexandrescu, Andrei T

    2016-01-01

    Amyloid fibrils are associated with a number of human diseases. These aggregatively misfolded intermolecular β-sheet assemblies constitute some of the most challenging targets in structural biology because to their complexity, size, and insolubility. Here, protocols and controls are described for experiments designed to study hydrogen-bonding in amyloid fibrils indirectly, by transferring information about amide proton occupancy in the fibrils to the dimethyl sulfoxide-denatured state. Since the denatured state is amenable to solution NMR spectroscopy, the method can provide residue-level-resolution data on hydrogen exchange for the monomers that make up the fibrils. PMID:26453215

  20. NMR measurements in SSC dipole D00001

    SciTech Connect

    Kuchnir, M.; Schmidt, E.E.; Hanft, R.W.; Strait, J.B.

    1986-09-12

    The first 16.5 m long SSC dipole magnet (D00001) had its field intensity measured as a function of position with a custom made NMR magnetometer. A short description of the probe is presented. The data obtained (most of it near 2 T spaced apart by one inch) shows an average transfer function of 1.02830 T/KA with position dependent values deviating from the average by up to .00130 T/KA revealing contruction inhomogeneities that were measured with a sensitivity of 25 ppM.

  1. 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

  2. Touch NMR: An NMR Data Processing Application for the iPad

    ERIC Educational Resources Information Center

    Li, Qiyue; Chen, Zhiwei; Yan, Zhiping; Wang, Cheng; Chen, Zhong

    2014-01-01

    Nuclear magnetic resonance (NMR) spectroscopy has become one of the most powerful technologies to aid research in numerous scientific disciplines. With the development of consumer electronics, mobile devices have played increasingly important roles in our daily life. However, there is currently no application available for mobile devices able to…

  3. High resolution 1H NMR of a lipid cubic phase using a solution NMR probe

    NASA Astrophysics Data System (ADS)

    Boyle-Roden, E.; Hoefer, N.; Dey, K. K.; Grandinetti, P. J.; Caffrey, M.

    2007-11-01

    The cubic mesophase formed by monoacylglycerols and water is an important medium for the in meso crystallogenesis of membrane proteins. To investigate molecular level lipid and additive interactions within the cubic phase, a method was developed for improving the resolution of 1H NMR spectra when using a conventional solution state NMR probe. Using this approach we obtained well-resolved J-coupling multiplets in the one-dimensional NMR spectrum of the cubic-Ia3d phase prepared with hydrated monoolein. A high resolution t-ROESY two-dimensional 1H NMR spectrum of the cubic-Ia3d phase is also reported. Using this new methodology, we have investigated the interaction of two additive molecules, L-tryptophan and ruthenium-tris(2,2-bipyridyl) dichloride (rubipy), with the cubic mesophase. Based on the measured chemical shift differences when changing from an aqueous solution to the cubic phase, we conclude that L-tryptophan experiences specific interactions with the bilayer interface, whereas rubipy remains in the aqueous channels and does not associate with the lipid bilayer.

  4. 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.

  5. 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

  6. Characterizing carbohydrate-protein interactions by NMR

    PubMed Central

    Bewley, Carole A.; Shahzad-ul-Hussan, Syed

    2013-01-01

    Interactions between proteins and soluble carbohydrates and/or surface displayed glycans are central to countless recognition, attachment and signaling events in biology. The physical chemical features associated with these binding events vary considerably, depending on the biological system of interest. For example, carbohydrate-protein interactions can be stoichiometric or multivalent, the protein receptors can be monomeric or oligomeric, and the specificity of recognition can be highly stringent or rather promiscuous. Equilibrium dissociation constants for carbohydrate binding are known to vary from micromolar to millimolar, with weak interactions being far more prevalent; and individual carbohydrate binding sites can be truly symmetrical or merely homologous, and hence, the affinities of individual sites within a single protein can vary, as can the order of binding. Several factors, including the weak affinities with which glycans bind their protein receptors, the dynamic nature of the glycans themselves, and the non-equivalent interactions among oligomeric carbohydrate receptors, have made NMR an especially powerful tool for studying and defining carbohydrate-protein interactions. Here we describe those NMR approaches that have proven to be the most robust in characterizing these systems, and explain what type of information can (or cannot) be obtained from each. Our goal is to provide to the reader the information necessary for selecting the correct experiment or sets of experiments to characterize their carbohydrate-protein interaction of interest. PMID:23784792

  7. 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.

  8. 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

  9. NMR measurements in solutions of dialkylimidazolium haloaluminates

    SciTech Connect

    Takahashi, S.; Saboungi, M.L.; Klingler, R.J.; Chen, M.J.; Rathke, J.W.

    1992-06-01

    {sup 27}Al and {sup 35}Cl NMR spectra of AlCl{sub 3}-1-ethyl-3-methyl imidazolium chloride (EMIC) melts were measured for initial compositions ranging from 50 to 67 mol % AlCl{sub 3} at various temperatures. It was shown by changing the preaquisition delay time (DE value) that the dominant aluminum species are AlCl{sub 4}{sup {minus}} in the melt formed by mixing 50 mol % with EMIC and Al{sub 2}Cl{sub 7}{sup {minus}} in the 67 mol % AlCl{sub 3} melt. In the equimolar mixture, the chemical shift of {sup 27}Al NMR spectrum is 103.28 ppm and the line width is 22.83Hz. In the 67 mol % AlCl{sub 3} mixture, the chemical shift is 103.41 ppm and the line width is 2624Hz. A third species observed at 97 ppm in the {sup 27}Al spectra for the 55 and 60 mol % AlCl{sub 3} mixtures is identified to be a product of the reaction with residual water. The relaxation rates for each species in the melts were determined.

  10. Methods for spatial localization in NMR

    SciTech Connect

    Rath, A.R.

    1985-01-01

    Several unique coil configurations were developed that have applications in nuclear magnetic resonance. These include a number of designs appropriate for use as rf surface coils, and two configurations developed as NMR magnets. The magnetic field profiles were calculated for each of these designs, from which field strength and homogeneity information were obtained. The rf coil configurations modelled include the opposed loop, opposed half loop, bicycle wheel, opposed bicycle wheel, and semi-toroid. The opposed loop design was studied in detail in terms of the theoretical spatial sensitivity and selectivity it offers. A number of NMR experiments were performed to test the validity of these theoretical calculations. This configuration produces a field that is substantially reduced near the coil itself, compared with the field produced by a single loop surface coil, but that rises to a maximum along the coil axis yielding a somewhat homogeneous region that may be used to achieve a degree of spatial localization. Several comparison schemes are used to evaluate the relative advantages and disadvantages of both the single loop and the opposed loop coil. The opposed coil concept also has been applied to the design of magnets. The results of calculations on the homogeneity and field strength possible with an opposed solenoid magnet are presented.