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Sample records for 23na nmr imaging

  1. The molecular environment of intracellular sodium: 23Na NMR relaxation.

    PubMed

    Rooney, W D; Springer, C S

    1991-10-01

    The comprehensive approach described in the accompanying paper is illustrated here with the 23Na signal of a concentrated solution of bovine serum albumin (BSA) in saline and the intracellular (Nai) 23Na resonance of a dense suspension of Na(+)-loaded yeast cells. We use frequency shift reagents to discriminate the latter from the extracellular resonance. We find that the Nai signal corresponds to that of an effective single population of Na+ ions exhibiting a single type c spectrum. This is true despite the fact that the yeast protoplasm is too large and too compartmentalized for a given Na+ ion to sample its entirety on the relevant NMR timescale. Our results show clearly that, in addition to the decay of transverse magnetization, the recovery of longitudinal magnetization is biexponential. This is required for a type c spectrum but has not often been detected. The temperature dependence of the relaxation rate constants of the Nai resonance is not consistent with either a simple Debye process or a discrete exchange mechanism connecting two sites in the fast limit. We have fitted the data using an asymmetric continuous distribution of correlation times for the fluctuations of electric field gradients sensed by the Nai nuclei. The analogous distribution function for the Na+ in a 44% (w/w) BSA solution is quite similar to that of the Nai at the same temperature. This suggests that while the macromolecular environment of the Nai ions is quite congested, it is also isotropic on quite a small spatial scale. Also, one can use the correlation time distribution function, obtained from fitting the relaxation data, to calculate a relaxometry curve. This is useful because experimental 23Na relaxometry is difficult. The calculated curve may be a reasonable model for the mostly extracellular 23Na resonance encountered in vivo. PMID:1751346

  2. 23Na NMR study of the effect of organic osmolytes on DNA counterion atmosphere.

    PubMed Central

    Flock, S; Labarbe, R; Houssier, C

    1996-01-01

    The effect of different organic osmolytes on the DNA counterion condensation layer has been investigated by 23Na NMR relaxation measurements. The zwitterionic compounds glycine, beta-alanine, 4-aminobutyric acid, and 6-aminocaproic acid have shown an increasing capacity to decrease the amount of sodium ions in the vicinity of the macromolecule. The experimental data have been correlated with the dielectric constant increase in their corresponding solutions and have been compared with the prediction of counterion condensation theory. Polyols (sorbitol and mannitol) did not display the same effect. These compounds largely increase the relaxation rate of sodium ions in the proximity of DNA, unlike the zwitterionic compounds. This probably results from a perturbation of the water dynamic around the macromolecule, of the primary or secondary hydration shell of the sodium nuclei involved, or both. PMID:8874025

  3. Sepsis does not alter red blood cell glucose metabolism or Na+ concentration: A 2H-, 23Na-NMR study

    SciTech Connect

    Hotchkiss, R.S.; Song, S.K.; Ling, C.S.; Ackerman, J.J.; Karl, I.E. )

    1990-01-01

    The effects of sepsis on intracellular Na+ concentration ((Na+)i) and glucose metabolism were examined in rat red blood cells (RBCs) by using 23Na- and 2H-nuclear magnetic resonance (NMR) spectroscopy. Sepsis was induced in 15 halothane-anesthetized female Sprague-Dawley rats by using the cecal ligation and perforation technique; 14 control rats underwent cecal manipulation without ligation. The animals were fasted for 36 h, but allowed free access to water. At 36 h postsurgery, RBCs were examined by 23Na-NMR by using dysprosium tripolyphosphate as a chemical shift reagent. Human RBCs from 17 critically ill nonseptic patients and from 7 patients who were diagnosed as septic were also examined for (Na+)i. Five rat RBC specimens had (Na+)i determined by both 23Na-NMR and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). For glucose metabolism studies, RBCs from septic and control rats were suspended in modified Krebs-Henseleit buffer containing (6,6-2H2)glucose and examined by 2H-NMR. No significant differences in (Na+)i or glucose utilization were found in RBCs from control or septic rats. There were no differences in (Na+)i in the two groups of patients. The (Na+)i determined by NMR spectroscopy agreed closely with measurements using ICP-AES and establish that 100% of the (Na+)i of the RBC is visible by NMR. Glucose measurements determined by 2H-NMR correlated closely (correlation coefficient = 0.93) with enzymatic analysis. These studies showed no evidence that sepsis disturbed RBC membrane function or metabolism.

  4. Solid-state 23Na and 7Li NMR investigations of sodium- and lithium-reduced mesoporous titanium oxides.

    PubMed

    Lo, Andy Y H; Schurko, Robert W; Vettraino, Melissa; Skadtchenko, Boris O; Trudeau, Michel; Antonelli, David M

    2006-02-20

    Mesoporous titanium oxide synthesized using a dodecylamine template was treated with 0.2, 0.6, and 1.0 equiv of Li- or Na-naphthalene. The composite materials were characterized by nitrogen adsorption, powder X-ray diffraction, X-ray photoelectron spectroscopy, elemental analysis, thermogravimetric analysis, and solid-state 23Na and 7Li NMR spectroscopy. In all cases the wormhole mesoporosity was retained as evidenced by BET surface areas from 400 to 700 m(2)/g, Horvath-Kawazoe pore sizes in the 20 Angstroms range, and a lack of hysteresis in the nitrogen adsorption isotherms. Variable-temperature conductivity studies show that the Li-reduced materials are semiconductors, with conductivity values 3 orders of magnitude higher than those of the Na-reduced materials. Electrochemical measurements demonstrate reversible intercalation/deintercalation of Li+ ions into pristine mesoporous Ti oxides with good cycling capacity. Solid-state 23Na NMR reveals two distinct Na environments: one corresponding to sodium ions in the mesoporous channels and the other corresponding to sodium ions intercalated into the metal framework. 23Na NMR spectra also indicate that the relative population of the framework site increases with increased reduction levels. Solid-state 7Li NMR spectra display a single broad resonance, which increases in breadth with increased reduction levels, though individual resonances inferring the presence of channel and framework Li species are not resolved. Comparisons of the lithium chemical shifts with published values suggests an "anatase-like structure" with no long-range order in the least-reduced samples but a "lithium titanate-like structure" with no long-range order in the higher reduced materials. PMID:16472000

  5. Time course of myocardial sodium accumulation after burn trauma: a (31)P- and (23)Na-NMR study.

    PubMed

    Sikes, P J; Zhao, P; Maass, D L; Horton, J W

    2001-12-01

    In this study, (23)Na- and (31)P- nuclear magnetic resonance (NMR) spectra were examined in perfused rat hearts harvested 1, 2, 4, and 24 h after 40% total body surface area burn trauma and lactated Ringer resuscitation, 4 ml. kg(-1). %(-1) burn. (23)Na-NMR spectroscopy monitored myocardial intracellular Na+ using the paramagnetic shift reagent thulium 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetra(methylenephosphonic acid). Left ventricular function, cardiac high-energy phosphates (ATP/PCr), and myocyte intracellular pH were studied by using (31)P NMR spectroscopy to examine the hypothesis that burn-mediated acidification of cardiomyocytes contributes to subsequent Na+ accumulation by this cell population. Intracellular Na+ accumulation was confirmed by sodium-binding benzofuran isophthalate loading and fluorescence spectroscopy in cardiomyocytes isolated 1, 2, 4, 8, 12, 18, and 24 h postburn. This myocyte Na+ accumulation as early as 2 h postburn occurred despite no changes in cardiac ATP/PCr and intracellular pH. Left ventricular function progressively decreased after burn trauma. Cardiomyocyte Na+ accumulation paralleled cardiac contractile dysfunction, suggesting that myocardial Na+ overload contributes, in part, to the progressive postburn decrease in ventricular performance. PMID:11717236

  6. 23Na NMR and FT-IR studies of sodium complexes with the ionophore lasalocid in solution

    NASA Astrophysics Data System (ADS)

    Schroeder, G.; Gierczyk, B.; Brzezinski, B.; Różalski, B.; Bartl, F.; Zundel, G.; Sośnicki, J.; Grech, E.

    2000-01-01

    Lasalocid forms 1:1 or 2:2 complexes with sodium ions. The process of complexation was studied in different solvents at various temperatures by 23Na NMR. The formation constants and Δ G values were determined. The nature of the complex between lasalocid and Na + ions was also studied by FT-IR spectroscopy. In chloroform, a 2:2 complex of lasalocid and Na + ions is formed. A continuous absorption is observed in the far FT-IR spectrum of this complex. It indicates the large Na + polarizability due to fast fluctuations of the Na + ions in multiminima potentials, in the dimeric structure.

  7. Four-dimensional 1H and 23Na imaging using continuously oscillating gradients.

    PubMed

    Star-Lack, J M; Roos, M S; Wong, S T; Schepkin, V D; Budinger, T F

    1997-02-01

    A class of fast magnetic spectroscopic imaging methods using continuously oscillating gradients for four-dimensional (three spatial and one spectral) localization is introduced. Sampling may start immediately following the application of an RF excitation pulse, thus enabling measurement of spin density, chemical shift, and relaxation rates of short-T2 species. For spatial localization, steady-state sinusoidal gradient waveforms are used to sample a ball in k space. The two types of trajectories presented include: (1) continuously oscillating gradients with continuously rotating direction used for steady-state free-precession imaging and (2) continuously oscillating gradients followed by a spoiler directed along discrete projections. Design criteria are given and spatial-spectral and spatial-temporal reconstruction methods are developed. Theoretical point-spread functions and signal-to-noise ratios are derived while considering T2*, off-resonance effects, and RF excitation options. Experimental phantom, in vivo, and in vitro 1H and 23Na images collected at 2.35 T are presented. The 1H images were acquired with isotropic spatial resolution ranging from 0.03 to 0.27 cm3 and gradient-oscillation frequencies ranging from 600 to 700 Hz, thus allowing for the separation of water and lipid signals within a voxel. The 23Na images, acquired with 500 and 800 Hz gradient waveforms and 0.70 cm3 isotropic resolution, were resolved in the time domain, yielding spatially localized FIDs. PMID:9169223

  8. Interface Induced Growth and Transformation of Polymer-Conjugated Proto-Crystalline Phases in Aluminosilicate Hybrids: A Multiple-Quantum (23)Na-(23)Na MAS NMR Correlation Spectroscopy Study.

    PubMed

    Brus, Jiri; Kobera, Libor; Urbanova, Martina; Doušová, Barbora; Lhotka, Miloslav; Koloušek, David; Kotek, Jiří; Čuba, Pavel; Czernek, Jiri; Dědeček, Jiří

    2016-03-22

    Nanostructured materials typically offer enhanced physicochemical properties because of their large interfacial area. In this contribution, we present a comprehensive structural characterization of aluminosilicate hybrids with polymer-conjugated nanosized zeolites specifically grown at the organic-inorganic interface. The inorganic amorphous Al-O-Si framework is formed by alkali-activated low-temperature transformation of metakaoline, whereas simultaneous copolymerization of organic comonomers creates a secondary epoxide network covalently bound to the aluminosilicate matrix. This secondary epoxide phase not only enhances the mechanical integrity of the resulting hybrids but also introduces additional binding sites accessible for compensating negative charge on the aluminosilicate framework. This way, the polymer network initiates growth and subsequent transformation of protocrystalline short-range ordered zeolite domains that are located at the organic-inorganic interface. By applying an experimental approach based on 2D (23)Na-(23)Na double-quantum (DQ) MAS NMR spectroscopy, we discovered multiple sodium binding sites in these protocrystalline domains, in which immobilized Na(+) ions form pairs or small clusters. It is further demonstrated that these sites, the local geometry of which allows for the pairing of sodium ions, are preferentially occupied by Pb(2+) ions during the ion exchange. The proposed synthesis protocol thus allows for the preparation of a novel type of geopolymer hybrids with polymer-conjugated zeolite phases suitable for capturing and storage of metal cations. The demonstrated (23)Na-(23)Na DQ MAS NMR combined with DFT calculations represents a suitable approach for understanding the role of Na(+) ions in aluminositicate solids and related inorganic-organic hybrids, particularly their specific arrangement and clustering at interfacial areas. PMID:26931131

  9. Lanthanide complexes of aminophosphonates as shift reagents for 7Li and 23Na NMR studies in biological systems.

    PubMed

    Ramasamy, R; Castro, M M; de Freitas, D M; Geraldes, C F

    1992-01-01

    A systematic NMR characterization of various Dy(III) complexes of linear and macrocyclic aminophosphonates as 7Li and 23Na NMR shift reagents for biological systems was undertaken. Their efficacy as shift reagents (SR) was tested under constant aqueous solution ionic strength conditions at pH 7.5 as a function of rho = [SR]/[M+]. Further characterization of the two best SRs, Dy(PcPcP)2(7-) and Dy(DOTP)5-, led to the conclusion that, although quite sensitive to solution pH and the presence of alkali metal ions and Mg2+ and Ca2+, these complexes were stable towards hydrolysis by phosphatases. The lack of precipitation of its solutions in the presence of Ca2+, allowed the choice of Dy(DOTP)5- as the best overall SR for biological studies. Other SRs, like Dy(TTHA)3-, although less sensitive to pH and to divalent ions, require significantly higher concentrations to yield the same shifts, leading to large bulk susceptibility artifacts in perfused tissues and organs. PMID:1467337

  10. Positive and Negative Mixed Glass Former Effects in Sodium Borosilicate and Borophosphate Glasses Studied by (23)Na NMR.

    PubMed

    Storek, Michael; Adjei-Acheamfour, Mischa; Christensen, Randilynn; Martin, Steve W; Böhmer, Roland

    2016-05-19

    Glasses with varying compositions of constituent network formers but constant mobile ion content can display minima or maxima in their ion transport which are known as the negative or the positive mixed glass former effect, MGFE, respectively. Various nuclear magnetic resonance (NMR) techniques are used to probe the ion hopping dynamics via the (23)Na nucleus on the microscopic level, and the results are compared with those from conductivity spectroscopy, which are more sensitive to the macroscopic charge carrier mobility. In this way, the current work examines two series of sodium borosilicate and sodium borophosphate glasses that display positive and negative MGFEs, respectively, in the composition dependence of their Na(+) ion conductivities at intermediate compositions of boron oxide substitution for silicon oxide and phosphorus oxide, respectively. A coherent theoretical analysis is performed for these glasses which jointly captures the results from measurements of spin relaxation and central-transition line shapes. On this basis and including new information from (11)B magic-angle spinning NMR regarding the speciation in the sodium borosilicate glasses, a comparison is carried out with predictions from theoretical approaches, notably from the network unit trap model. This comparison yields detailed insights into how a variation of the boron oxide content and thus of either the population of silicon or phosphorus containing network-forming units with different charge-trapping capabilities leads to nonlinear changes of the microscopic transport properties. PMID:27092392

  11. Aggregation of double-tail sulfonate surfactants probed by /sup 23/Na NMR

    SciTech Connect

    Kilpatrick, P.K.; Miller, W.G.

    1984-04-12

    Analysis of sodium-23 NMR chemical shift and line-width data on sodium 4-(1-heptylnonyl)benzenesulfonate (SHBS) in water at 47/sup 0/C indicates the surfactant continuously aggregates in an anti- or weakly cooperative manner up to the surfactant solubility limit, a point beyond which a hydrated lamellar phase is in equilibrium with the surfactant-saturated isotropic solution. By contrast, sodium bis(2-ethylhexyl) sulfosuccinate (Aerosol OT) shows little if any aggregation up to the point of a highly cooperative micellization. Both chemical shift and line-width data indicate the presence of an isotropic solution-liquid crystal phase boundary; the line shape of a biphasic mixture of isotropic solution and lamellar liquid crystal is not motionally averaged, in contrast to a micellar solution, and thus differentiation between micelle formation and solubility boundary is possible. A multiple equilibrium treatment of stepwise amphiphile aggregate formation is used to model both highly cooperative surfactant association, i.e., micellization, and anti- or noncooperative association. The sodium counterion binding to surfactant aggregates was modelled by assuming the oligomers are spherical and have a constant surface charge density with all anionic head groups residing at the surface of the sphere. It was then assumed that the sodium ion exists in one of two environments: free or bound, each having a characteristic chemical shift and transverse relaxation rate. On the basis of a comparison of the model with experimental data, it was concluded that SHBS aggregate concentration decreases with increasing aggregate size; i.e., the aggregation is non- or weakly anticooperative, while Aerosol OT associates very cooperatively, the large degree of cooperativity being an indication of micelle formation.

  12. 23Na and 35/37Cl as NMR probes of growth and shape of sodium taurodeoxycholate micellar aggregates in the presence of NaCl.

    PubMed

    Asaro, Fioretta; Feruglio, Luigi; Galantini, Luciano; Nardelli, Alessia

    2013-02-15

    The growth of the aggregates of the dihydroxylated bile salt sodium taurodeoxycholate (NaTDC) upon NaCl addition and the involvement of the counterion were investigated by NMR spectroscopy of monoatomic ionic species. (23)Na T(1) values from 0.015, 0.100, and 0.200 mol kg(-1) NaTDC solutions in D(2)O, at variable NaCl content, proved to be sensitive to the transition from primary to secondary aggregates, which occurs in the former sample, and to intermicellar interaction. Some (79)Br NMR measurements were performed on a 0.100 mol kg(-1) NaTDC sample added by NaBr in place of NaCl for comparison purposes. The (23)Na, (35)Cl, and (37)Cl double quantum filtered (DQF) patterns, from the 0.100 mol kg(-1) NaTDC sample, and (23)Na ones also from the 0.200 mol kg(-1) NaTDC one, in the presence of 0.750 mol kg(-1) NaCl, are a clear manifestation of motional anisotropy. Moreover, the DQF spectra of (23)Na and (37)Cl, which possess close quadrupole moments, display a striking similarity. The DQF lineshapes were simulated exploiting the Scilab environment to obtain an estimate of the residual quadrupole splitting magnitude. These results support the description of NaTDC micelles as cylindrical aggregates, strongly interacting at high ionic strengths, and capable of association with added electrolytes. PMID:23127873

  13. Lead exchange into zeolite and clay minerals: A [sup 29]Si, [sub 27]Al, [sup 23]Na solid-state NMR study

    SciTech Connect

    Liang, J.J.; Sherriff, B.L. )

    1993-08-01

    Chabazite, vermiculite, montmorillonite, hectorite, and kaolinite were used to remove Pb, through ion exchange, from 0.01 M aqueous Pb(NO[sub 3])[sub 2] solutions. These minerals contained 27 (Na-chabazite), 16, 9, 9, and 0.5 wt % of Pb, respectively, after equilibration with the solutions. Ion exchange reached equilibrium within 24 h for Na-chabazite and vermiculite, but in less than 5 min for montmorillonite and hectorite. Na-chabazite took up more Pb than natural (Ca, Na)-chabazite (7 wt % Pb), whereas no such difference was observed in different cation forms of the clay minerals. Calcite impurities, associated with the clay minerals, effectively removed Pb from the aqueous solutions by the precipitation of cerussite (PbCO[sub 3]). [sup 29]Si, [sup 27]Al, and [sup 23]Na magic angle spinning (MAS) nuclear magnetic resonance (NMR), [sup 23]Na double rotation (DOR) NMR, and [sup 23]Na variable-temperature MAS NMR were used to study the ion exchange mechanisms. In Na-chabazite, cations in all three possible sites take part in the fast chemical exchange. The chemical exchange passes from the fast exchange regime to the slow regime at [minus]80 to [minus]100[degrees]C. One site contains a relatively low population of exchangeable cations. The other two more shielded sites contain most of the exchangeable cation. The exchangeable cations in chabazite and vermiculite were found to be close to the SiO[sub 4] and AlO[sub 4] tetrahedra, while those in the other clay minerals were more distant. Two sites (or groups of sites) for exchangeable cations were observed in hectorite. Lead tended to occupy the one which corresponds to the [minus]8 ppM peak on the [sup 23]Na MAS NMR spectrum. The behavior of the exchangeable cations in the interlayer sites was similar in all the clay minerals studied. 27 refs., 7 figs., 4 tabs.

  14. Multiple quantum filtered 23Na NMR in the Langendorff perfused mouse heart: Ratio of triple/double quantum filtered signals correlates with [Na]i

    PubMed Central

    Eykyn, Thomas R.; Aksentijević, Dunja; Aughton, Karen L.; Southworth, Richard; Fuller, William; Shattock, Michael J.

    2015-01-01

    We investigate the potential of multiple quantum filtered (MQF) 23Na NMR to probe intracellular [Na]i in the Langendorff perfused mouse heart. In the presence of Tm(DOTP) shift reagent the triple quantum filtered (TQF) signal originated largely from the intracellular sodium pool with a 32 ± 6% contribution of the total TQF signal arising from extracellular sodium, whilst the rank 2 double-quantum filtered signal (DQF), acquired with a 54.7° flip-angle pulse, originated exclusively from the extracellular sodium pool. Given the different cellular origins of the 23Na MQF signals we propose that the TQF/DQF ratio can be used as a semi-quantitative measure of [Na]i in the mouse heart. We demonstrate a good correlation of this ratio with [Na]i measured with shift reagent at baseline and under conditions of elevated [Na]i. We compare the measurements of [Na]i using both shift reagent and TQF/DQF ratio in a cohort of wild type mouse hearts and in a transgenic PLM3SA mouse expressing a non-phosphorylatable form of phospholemman, showing a modest but measurable elevation of baseline [Na]i. MQF filtered 23Na NMR is a potentially useful tool for studying normal and pathophysiological changes in [Na]i, particularly in transgenic mouse models with altered Na regulation. PMID:26196304

  15. In Situ 13C and 23Na Magic Angle Spinning NMR Investigation of Supercritical CO2 Incorporation in Smectite-Natural Organic Matter Composites

    SciTech Connect

    Bowers, Geoffrey M.; Hoyt, David W.; Burton, Sarah D.; Ferguson, Brennan O.; Varga, Tamas; Kirkpatrick, Robert J.

    2014-01-29

    This paper presents an in situ NMR study of clay-natural organic polymer systems (a hectoritehumic acid [HA] composite) under CO2 storage reservoir conditions (90 bars CO2 pressure, 50°C). The 13C and 23Na NMR data show that supercritical CO2 interacts more strongly with the composite than with the base clay and does not react to form other C-containing species over several days at elevated CO2. With and without organic matter, the data suggest that CO2 enters the interlayer space of Na-hectorite equilibrated at 43% relative humidity. The presence of supercritical CO2 also leads to increased 23Na signal intensity, reduced line width at half height, increased basal width, more rapid 23Na T1 relaxation rates, and a shift to more positive resonance frequencies. Larger changes are observed for the hectorite-HA composite than for the base clay. In light of recently reported MD simulations of other polymer-Na-smectite composites, we interpret the observed changes as an increase in the rate of Na+ site hopping in the presence of supercritical CO2, the presence of potential new Na+ sorption sites when the humic acid is present, and perhaps an accompanying increase in the number of Na+ ions actively involved in site hopping. The results suggest that the presence of organic material either in clay interlayers or on external particle surfaces can significantly affect the behavior of supercritical CO2 and the mobility of metal ions in reservoir rocks.

  16. 1H and 23Na MAS NMR spectroscopy of cationic species in CO2 selective alkaline earth metal porous silicoaluminophosphates prepared via liquid and solid state ion exchange

    NASA Astrophysics Data System (ADS)

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

    2012-07-01

    The location of extraframework cations in Sr2+ and Ba2+ ion-exchanged SAPO-34 was estimated by means of 1H and 23Na MAS NMR spectroscopy and spectral deconvolution. Incorporation of the alkaline earth metal cations onto the SAPO framework was achieved via liquid state ion exchange, coupled partial detemplation/solid-state ion exchange, and combination of both techniques. MAS NMR revealed that the level of ion exchange was limited by the presence of protons and sodium cations near hexagonal prisms (site SI), which are relatively difficult to exchange with the alkaline earth metal due to steric and charge repulsion criteria. In addition, the presence of ammonium cations in the supercages facilitated the exchange of otherwise tenacious hydrogen as corroborated by unit cell compositional data as well as enhanced CO2 adsorption at low partial pressures. The extraframework ammonium species were produced from partial detemplation of the structure-directing agent employed for the SAPO-34 synthesis, tetraethylammonium.

  17. Thermotropic ionic liquid crystals. II. 1H and 23Na NMR study of the smectic mesophase of molten sodium n-butyrate and sodium isovalerate

    NASA Astrophysics Data System (ADS)

    Bonekamp, J. E.; Eguchi, T.; Plesko, S.; Jonas, J.

    1983-08-01

    The 1H and 23Na NMR studies of smectic ionic mesophases of molten sodium n-butyrate and sodium isovalerate are reported over the temperature range of the stability of the liquid crystalline phases. The 1H spin-lattice relaxation times T1 at ν0=9.2, 24.3, and 60 MHz for the anions of both the systems are interpreted in terms of diffusion intermolecular relaxation mechanism. The predicted anion diffusion coefficients are in agreement with those measured directly by spin-echo technique and indicate that the anion diffuses rapidly. In contrast to the T1 relaxation mechanism the results obtained for the proton relaxation times in the rotating coordinate frame T1ρ indicate that the order-fluctuation relaxation mechanism determines the frequency dispersion of T1ρ. The analysis of the T1ρ data provides an approximate measure of the order parameter S as a function of temperature. Fourier transform spectra of the 23Na transitions show that the electric field gradient (EFG) at the Na+ ion is nonaveraged and of such a strength as to produce a second order quadrupole effect in the spectra of the central transition. From the first-order splitting, the quadrupole coupling constant (QCC) is obtained as a function of temperature. The gradual temperature change of QCC demonstrates that only a single liquid crystalline phase exists over the temperature interval of the stability of the smectic mesophase. Using approximate analysis the correlation time τc for the EFG fluctuation is obtained from the 23Na T1 data for the melts of both sodium n-butyrate and sodium isovalerate.

  18. Competition between Na + and Li + for Unsealed and Cytoskeleton-Depleted Human Red Blood Cell Membrane: A 23Na Multiple Quantum Filtered and 7Li NMR Relaxation Study

    NASA Astrophysics Data System (ADS)

    Srinivasan, Chandra; Minadeo, Nicole; Toon, Jason; Graham, Daniel; Mota de Freitas, Duarte; Geraldes, Carlos F. G. C.

    1999-09-01

    Evidence for competition between Li+ and Na+ for binding sites of human unsealed and cytoskeleton-depleted human red blood cell (csdRBC) membranes was obtained from the effect of added Li+ upon the 23Na double quantum filtered (DQF) and triple quantum filtered (TQF) NMR signals of Na+-containing red blood cell (RBC) membrane suspensions. We found that, at low ionic strength, the observed quenching effect of Li+ on the 23Na TQF and DQF signal intensity probed Li+/Na+ competition for isotropic binding sites only. Membrane cytoskeleton depletion significantly decreased the isotropic signal intensity, strongly affecting the binding of Na+ to isotropic membrane sites, but had no effect on Li+/Na+ competition for those sites. Through the observed 23Na DQF NMR spectra, which allow probing of both isotropic and anisotropic Na+ motion, we found anisotropic membrane binding sites for Na+ when the total ionic strength was higher than 40 mM. This is a consequence of ionic strength effects on the conformation of the cytoskeleton, in particular on the dimer-tetramer equilibrium of spectrin. The determinant involvement of the cytoskeleton in the anisotropy of Na+ motion at the membrane surface was demonstrated by the isotropy of the DQF spectra of csdRBC membranes even at high ionic strength. Li+ addition initially quenched the isotropic signal the most, indicating preferential Li+/Na+ competition for the isotropic membrane sites. High ionic strength also increased the intensity of the anisotropic signal, due to its effect on the restructuring of the membrane cytoskeleton. Further Li+ addition competed with Na+ for those sites, quenching the anisotropic signal. 7Li T1 relaxation data for Li+-containing suspensions of unsealed and csdRBC membranes, in the absence and presence of Na+ at low ionic strength, showed that cytoskeleton depletion does not affect the affinity of Na+ for the RBC membrane, but increases the affinity of Li+ by 50%. This clearly indicates that cytoskeleton

  19. Triple-quantum filtered NMR imaging of sodium in the human brain

    SciTech Connect

    Keltner, J.R.

    1993-04-01

    In the past multiple-quantum filtered imaging of biexponential relaxation sodium-23 nuclei in the human brain has been limited by low signal to noise ratios; this thesis demonstrates that such imaging is feasible when using a modified gradient-selected triple-quantum filter at a repetition time which maximizes the signal to noise ratio. Nuclear magnetic resonance imaging of biexponential relaxation sodium-23 ({sup 23}Na) nuclei in the human brain may be useful for detecting ischemia, cancer, and pathophysiology related to manic-depression. Conventional single-quantum NMR imaging of in vivo biexponential relaxation {sup 23}Na signals is complicated by the presence of single-exponential relaxation {sup 23}Na signals. Multiple-quantum filters may be used to selectively image biexponential relaxation {sup 23}Na signals since these filters suppress single-exponential relaxation {sup 23}Na signals. In this thesis, the typical repetition times (200--300 ms) used for in vivo multiple-quantum filtered {sup 23}Na experiments are shown to be approximately 5 times greater than the optimal repetition time which maximizes multiple-quantum filtered SNR. Calculations and experimental verification show that the gradient-selected triple-quantum (GS3Q) filtered SNR for {sup 23}Na in a 4% agarose gel increases by a factor of two as the repetition time decreases from 300 ms to 55 ms. The measured relaxation times of the {sup 23}Na in the 4% agarose gel were similar to in vivo {sup 23}Na relaxation times.

  20. The effects of pre-salting methods on salt and water distribution of heavily salted cod, as analyzed by (1)H and (23)Na MRI, (23)Na NMR, low-field NMR and physicochemical analysis.

    PubMed

    Gudjónsdóttir, María; Traoré, Amidou; Jónsson, Ásbjörn; Karlsdóttir, Magnea Gudrún; Arason, Sigurjón

    2015-12-01

    The effect of different pre-salting methods (brine injection with salt with/without polyphosphates, brining and pickling) on the water and salt distribution in dry salted Atlantic cod (Gadus morhua) fillets was studied with proton and sodium NMR and MRI methods, supported by physicochemical analysis of salt and water content as well as water holding capacity. The study indicated that double head brine injection with salt and phosphates lead to the least heterogeneous water distribution, while pickle salting had the least heterogeneous salt distribution. Fillets from all treatments contained spots with unsaturated brine, increasing the risk of microbial denaturation of the fillets during storage. Since a homogeneous water and salt distribution was not achieved with the studied pre-salting methods, further optimizations of the salting process, including the pre-salting and dry salting steps, must be made in the future. PMID:26041245

  1. Short-T2 Imaging for Quantifying Concentration of Sodium (23Na) of Bi-Exponential T2 Relaxation

    PubMed Central

    Qian, Yongxian; Panigrahy, Ashok; Laymon, Charles M.; Lee, Vincent K.; Drappatz, Jan; Lieberman, Frank S.; Boada, Fernando E.; Mountz, James M.

    2014-01-01

    Purpose This work intends to demonstrate a new method for quantifying concentration of sodium (23Na) of bi-exponential T2 relaxation in patients on MRI scanners at 3.0 Tesla. Theory Two single-quantum (SQ) sodium images acquired at very-short and short echo times (TE=0.5 and 5.0ms) are subtracted to produce an image of the short-T2 component of the bi-exponential (or bound) sodium. An integrated calibration on the SQ and short-T2 images quantifies both total and bound sodium concentrations. Methods Numerical models were used to evaluate signal response of the proposed method to the short-T2 components. MRI scans on agar phantoms and brain tumor patients were performed to assess accuracy and performance of the proposed method, in comparison with a conventional method of triple-quantum filtering. Results A good linear relation (R2=0.98) was attained between the short-T2 image intensity and concentration of bound sodium. A reduced total scan time of 22min was achieved under the SAR restriction for human studies in quantifying both total and bound sodium concentrations. Conclusion The proposed method is feasible for quantifying bound sodium concentration in routine clinical settings at 3.0 Tesla. PMID:25078966

  2. Quantification of the Contribution of Extracellular Sodium to 23Na Multiple-Quantum-Filtered NMR Spectra of Suspensions of Human Red Blood Cells

    NASA Astrophysics Data System (ADS)

    Knubovets, Tatyana; Shinar, Hadassah; Navon, Gil

    1998-03-01

    23Na double-quantum-filtered (DQF) NMR enables the detection of anisotropic motion of sodium ions due to their interaction with ordered structures in biological tissues. Using the technique, anisotropic motion was found for sodium ions in mammalian red blood cell suspensions (RBC) and the effect was shown to correlate with the integrity of membrane cytoskeleton. In the present study relative contributions to the DQF and triple-quantum-filtered (TQF) spectra of sodium bound to anisotropic and isotropic binding sites in the intra- and extracellular sodium pools (Na content being 15 and 150 mM, respectively) of human RBC were quantified for different hematocrits. DQF spectra were measured by a modified Jeener-Broekaert pulse sequence which enabled exclusive detection of anisotropically moving sodium ions. The relative contributions of the extracellular sodium to the TQF and DQF spectra decreased as the hematocrit increased, but their efficiency relative to the sodium content increased. The contribution of the extracellular sodium to the TQF signal was found to dominate the spectrum of the RBC suspension at all hematocrits studied. The contribution of the extracellular sodium to the DQF was significantly smaller than that to the TQF and was only 22% at a high hematocrit of about 90%.

  3. 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.

  4. 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.''

  5. 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.

  6. Molecular and electron-spin structures of a ring-shaped mixed-valence polyoxovanadate (IV, V) studied by (11)B and (23)Na solid-state NMR spectroscopy and DFT calculations.

    PubMed

    Iijima, Takahiro; Yamase, Toshihiro; Nishimura, Katsuyuki

    2016-01-01

    (11)B and (23)Na solid-state nuclear magnetic resonance (NMR) spectra of ring-shaped paramagnetic crystals of H15[V7(IV)V5(V)B32O84Na4]·13H2O containing seven d(1) electrons from V(IV) were studied. Magic-angle-spinning (MAS) and multiple-quantum MAS NMR experiments were performed at moderate (9.4T) and ultrahigh magnetic fields (21.6T). The NMR parameters for quadrupole and isotropic chemical shift interactions were estimated by simulation of the NMR spectra and from relativistic density functional theory (DFT) calculations. Four Na ions incorporated into the framework were found to occupy four distinct sites with different populations. The DFT calculation showed that d(1) electrons with effectively one up-spin caused by strong antiferromagnetic interactions were delocalized over the 12V ions. PMID:27018827

  7. NMR relaxation behavior and quadrupole coupling constants of 39K and 23Na ions in glycerol. Comparisons with 39K tissue data

    NASA Astrophysics Data System (ADS)

    Wellard, R. Mark; Shehan, B. Philip; Craik, David J.; Adam, William R.

    The quadrupole coupling constants (qcc) for 39K and 23Na ions in glycerol have been calculated from linewidths measured as a function of temperature (which in turn results in changes in solution viscosity). The qcc of 39K in glycerol is found to be 1.7 MHz, and that of 23Na is 1.6 MHz. The relaxation behavior of 39K and 23Na ions in glycerol shows magnetic field and temperature dependence consistent with the equations for transverse relaxation more commonly used to describe the reorientation of nuclei in a molecular framework with intramolecular field gradients. It is shown, however, that τ c is not simply proportional to the ratio of viscosity/temperature (η T). The 39K qcc in glycerol and the value of 1.3 MHz estimated for this nucleus in aqueous solution are much greater than values of 0.075 to 0.12 MHz calculated from T 2 measurements of 39K in freshly excised rat tissues. This indicates that, in biological samples, processes such as exchange of potassium between intracellular compartments or diffusion of ions through locally ordered regions play a significant role in determining the effective quadrupole coupling constant and correlation time governing 39K relaxation. T1 and T2 measurements of rat muscle at two magnetic fields also indicate that a more complex correlation function may be required to describe the relaxation of 39K in tissue. Similar results and conclusions are found for 23Na.

  8. 23Na Magnetic Resonance Imaging of the Lower Leg of Acute Heart Failure Patients during Diuretic Treatment

    PubMed Central

    Hammon, Matthias; Grossmann, Susan; Linz, Peter; Kopp, Christoph; Dahlmann, Anke; Garlichs, Christoph; Janka, Rolf; Cavallaro, Alexander; Luft, Friedrich C.; Uder, Michael; Titze, Jens

    2015-01-01

    Objective Na+ can be stored in muscle and skin without commensurate water accumulation. The aim of this study was to assess Na+ and H2O in muscle and skin with MRI in acute heart failure patients before and after diuretic treatment and in a healthy cohort. Methods Nine patients (mean age 78 years; range 58–87) and nine age and gender-matched controls were studied. They underwent 23Na/1H-MRI at the calf with a custom-made knee coil. Patients were studied before and after diuretic therapy. 23Na-MRI gray-scale measurements of Na+-phantoms served to quantify Na+-concentrations. A fat-suppressed inversion recovery sequence was used to quantify H2O content. Results Plasma Na+-levels did not change during therapy. Mean Na+-concentrations in muscle and skin decreased after furosemide therapy (before therapy: 30.7±6.4 and 43.5±14.5 mmol/L; after therapy: 24.2±6.1 and 32.2±12.0 mmol/L; p˂0.05 and p˂0.01). Water content measurements did not differ significantly before and after furosemide therapy in muscle (p = 0.17) and only tended to be reduced in skin (p = 0.06). Na+-concentrations in calf muscle and skin of patients before and after diuretic therapy were significantly higher than in healthy subjects (18.3±2.5 and 21.1±2.3 mmol/L). Conclusions 23Na-MRI shows accumulation of Na+ in muscle and skin in patients with acute heart failure. Diuretic treatment can mobilize this Na+-deposition; however, contrary to expectations, water and Na+-mobilization are poorly correlated. PMID:26501774

  9. Spin dynamics in Na4-x Ir3O8 (x  =  0.3 and 0.7) investigated by 23Na NMR and μSR

    NASA Astrophysics Data System (ADS)

    Yoon, Sungwon; Baek, S.-H.; Balodhi, Ashiwini; Lee, W.-J.; Choi, K.-Y.; Watanabe, I.; Lord, J. S.; Büchner, B.; Suh, B. J.; Singh, Yogesh

    2015-12-01

    We report 23Na nuclear magnetic resonance (NMR) and zero-field (ZF) and longitudinal-field (LF) muon spin relaxation (μSR) measurements of the depleted hyperkagome compounds Na4-x Ir3O8 (x  =  0.3 and 0.7), which undergo an insulator-semimetal transition as a function of x. The 23Na spin-lattice relaxation rates, T1-1 , follow a T 2.5 power law behavior at accessible temperatures of T  =  120-350 K. A substantial temperature dependence of T1-1 indicates the presence of gapped excitations at elevated temperatures through the transition to a semimetallic phase. ZF-μSR results reveal that hole-doping leads to a melting of quasi-static order to a dynamically fluctuating state. The very slow muon depolarization rate which varies hardly with temperature indicates that spins are close to an itinerant limit in the largest doping x  =  0.7. The dynamic relaxation rates extracted from the LF-μSR spectra show a three-dimensional diffusive transport. Our combined NMR and μSR results suggest the occurrence of intriguing spin and charge excitations across the insulator-semimetal transition.

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

    SciTech Connect

    Arevalo-Hidalgo, Ana G.; Dugar, Sneha; Fu, Riqiang; Hernandez-Maldonado, Arturo J.

    2012-07-15

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

  11. 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.

  12. X-ray CT and NMR imaging of rocks

    SciTech Connect

    Vinegar, H.J.

    1986-03-01

    In little more than a decade, X-ray computerized tomography (CT) and nuclear magnetic resonance (NMR) imaging have become the premier modalities of medical radiology. Both of these imaging techniques also promise to be useful tools in petrophysics and reservoir engineering, because CT and NMR can nondestructively image a host of physical and chemical properties of porous rocks and multiple fluid phases contained within their pores. The images are taken within seconds to minutes, at reservoir temperatures and pressures, with spatial resolution on the millimeter and submillimeter level. The physical properties imaged by the two techniques are complementary. CT images bulk density and effective atomic number. NMR images the nuclide concentration, M/sub 0/, of a variety of nuclei (/sup 1/H, /sup 19/F, /sup 23/Na, /sup 31/P, etc.), their longitudinal and transverse relaxation-time curves (t/sub 1/ and t/sub 2/), and their chemical shift spectra. In rocks, CT images both rock matrix and pore fluids, while NMR images only mobile fluids and the interactions of these mobile fluids with the confining surfaces of the pores.

  13. 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.

  14. 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

  15. {sup 27}Al and {sup 23}Na MAS NMR and powder x-ray diffraction studies of sodium aluminate speciation and the mechanistics of aluminum hydroxide precipitation upon acid hydrolysis

    SciTech Connect

    Bradley, S.M.; Hanna, J.V.

    1994-08-24

    {sup 27}Al and {sup 23}Na MAS NMR, powder X-ray diffraction, and infrared spectroscopic investigations of freeze-dried sodium aluminates and aluminum hydroxides formed through acid hydrolysis have been undertaken, with OH/Al hydrolysis ratios between 5.3 and 2.8 being analyzed. Numerous {sup 27}AlNMR resonances were observed, the intensities of which vary as a function of OH/Al ratio, and these have been assigned to four-, five-, and six-coordinate aluminum species constituting a variety of structural moieties. The dominant species at an OH/Al ratio above 4.4 appears to be a Q{sup o}Na[Al(OH);{sub 4}] salt, as indicated by a {sup 27}Al resonance at 86.6 ppm. In addition, a second, broader resonance at 71.3 ppm demonstrates the simultaneous existence of further four-coordinate aluminum species linked thorough oxo bonds to other four-coordinate aluminums (e.g., Q{sup 2} [Al(OH);{sub 2}(OAl){sub 2}];{sup x-}). At an OH/Al ratio between 4.4 and 4.1, a water-soluble phase forms that contains both four- and six-coordinate aluminum. At OH/Al ratios fo 4.0 and below, a water-soluble phase forms that contains both four-and six-coordinate aluminum. AT OH/Al ratios of 4.0 and below, a water-insoluble phase exists possessing four-, five-, and six-coordinate aluminum. At OH/Al{le}3.9 range exhibits {sup 27}Al chemical shifts similar to those reported for transitional aluminas such as {gamma}-, {eta}-, and 0-Al{sub 2}O{sub 3} and an infrared spectrum similar to pseudo-spinel gels, suggesting that a pseudo-spinel intermediate is the first phase involved in the crystallization of gibbsite. The resonance assigned to five-coordinate aluminum probably results from species involved in the transformation of the pseudo-spinal phase to pseudo-boehmite. The formation of gibbssite on the acid hydrolysis of alkaline sodium aluminate solutions thus appears to follow the pathway pseudo-spinel {r_arrow} pseudo-boehmite {r_arrow} bayerite {r_arrow} gibbsite. 82 refs., 7 figs., 3 tabs.

  16. 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.

  17. Nanoscale phase quantification in lead-free (Bi1 /2Na1 /2) TiO3-BaTiO3 relaxor ferroelectrics by means of 23Na NMR

    NASA Astrophysics Data System (ADS)

    Groszewicz, Pedro B.; Breitzke, Hergen; Dittmer, Robert; Sapper, Eva; Jo, Wook; Buntkowsky, Gerd; Rödel, Jürgen

    2014-12-01

    We address the unsolved question on the structure of relaxor ferroelectrics at the atomic level by characterizing lead-free piezoceramic solid solutions (100 -x ) (Bi1 /2Na1 /2) TiO3-x BaTiO3 (BNT -x BT ) (for x =1 ,4 ,6 , and 15). Based on the relative intensity between spectral components in quadrupolar perturbed 23Na nuclear magnetic resonance, we present direct evidence of the coexistence of cubic and polar local symmetries in these relaxor ferroelectrics. In addition, we demonstrate how the cubic phase vanishes whenever a ferroelectric state is induced, either by field cooling or changing the dopant amount, supporting the relation between this cubic phase and the relaxor state.

  18. Application of 23Na MRI to Monitor Chemotherapeutic Response in RIF-1 Tumors1

    PubMed Central

    Babsky, Andriy M; Hekmatyar, Shahryar K; Zhang, Hong; Solomon, James L; Bansal, Navin

    2005-01-01

    Abstract Effects of an alkylating anticancer drug, cyclophosphamide (Cp), on 23Na signal intensity (23Na SI) and water apparent diffusion coefficient (ADC) were examined in subcutaneously-implanted radiation-induced fibrosarcoma (RIF-1) tumors by in vivo 23Na and 1H magnetic resonance imaging (MRI). MRI experiments were performed on untreated control (n = 5) and Cp-treated (n = 6) C3H mice, once before Cp injection (300 mg/kg) then daily for 3 days after treatment. Tumor volumes were significantly lower in treated animals 2 and 3 days posttreatment. At the same time points, MRI experiments showed an increase in both 23Na SI and water ADC in treated tumors, whereas control tumors did not show any significant changes. The correlation between 23Na SI and water ADC changes was dramatically increased in the Cp-treated group, suggesting that the observed increases in 23Na SI and water ADC were caused by the same mechanism. Histologic sections showed decreased cell density in the regions of increased 23Na and water ADC SI. Destructive chemical analysis showed that Cp treatment increased the relative extracellular space and tumor [Na+]. We conclude that the changes in water ADC and 23Na SI were largely due to an increase in extracellular space. 23Na MRI and 1H water ADC measurements may provide valuable noninvasive techniques for monitoring chemotherapeutic responses. PMID:16026645

  19. 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.

  20. 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.

  1. 7-T (35)Cl and (23)Na MR Imaging for Detection of Mutation-dependent Alterations in Muscular Edema and Fat Fraction with Sodium and Chloride Concentrations in Muscular Periodic Paralyses.

    PubMed

    Weber, Marc-André; Nagel, Armin M; Marschar, Anja M; Glemser, Philip; Jurkat-Rott, Karin; Wolf, Maya B; Ladd, Mark E; Schlemmer, Heinz-Peter; Kauczor, Hans-Ulrich; Lehmann-Horn, Frank

    2016-09-01

    Purpose To determine whether altered sodium (Na(+)) and chloride (Cl(-)) homeostasis can be visualized in periodic paralyses by using 7-T sodium 23 ((23)Na) and chlorine 35 ((35)Cl) magnetic resonance (MR) imaging. Materials and Methods Institutional review board approval and informed consent of all participants were obtained. (23)Na (repetition time msec/echo time msec, 160/0.35) and (35)Cl (40/0.6) MR imaging of both lower legs was performed with a 7-T whole-body system in patients with genetically confirmed hypokalemic periodic paralysis (Cav1.1-R1239H mutation, n = 5; Cav1.1-R528H mutation, n = 8) and Andersen-Tawil syndrome (n = 3) and in 16 healthy volunteers. Additionally, each participant underwent 3-T proton MR imaging on the same day by using T1-weighted, short-tau inversion-recovery, and Dixon-type sequences. Muscle edema was assessed on short-tau inversion-recovery images, fatty degeneration was assessed on T1-weighted images, and muscular fat fraction was quantified with Dixon-type imaging. Na(+) and Cl(-) were quantified in the soleus muscle by using three phantoms that contained 10-, 20-, and 30-mmol/L NaCl solution and 5% agarose gel as a reference. Parametric data for all subpopulations were tested by using one-way analysis of variance with the Dunnett test, and correlations were assessed with the Spearman rank correlation coefficient. Results Median muscular (23)Na concentration was higher in patients with Cav1.1-R1239H (34.7 mmol/L, P < .001), Cav1.1-R528H (32.0 mmol/L, P < .001), and Kir2.1 (24.3 mmol/L, P = .035) mutations than in healthy volunteers (19.9 mmol/L). Median muscular normalized (35)Cl signal intensity was higher in patients with Cav1.1-R1239H (27.6, P < .001) and Cav1.1-R528H (23.6, P < .001) than in healthy volunteers (12.6), but not in patients with the Kir2.1 mutation (14.3, P = .517). When compared with volunteers, patients with Cav1.1-R1239H and Cav1.1-R528H showed increased muscular edema (P < .001 and P = .003, respectively

  2. 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

  3. Information preserving image compression for archiving NMR images.

    PubMed

    Li, C C; Gokmen, M; Hirschman, A D; Wang, Y

    1991-01-01

    This paper presents a result on information preserving compression of NMR images for the archiving purpose. Both Lynch-Davisson coding and linear predictive coding have been studied. For NMR images of 256 x 256 x 12 resolution, the Lynch-Davisson coding with a block size of 64 as applied to prediction error sequences in the Gray code bit planes of each image gave an average compression ratio of 2.3:1 for 14 testing images. The predictive coding with a third order linear predictor and the Huffman encoding of the prediction error gave an average compression ratio of 3.1:1 for 54 images under test, while the maximum compression ratio achieved was 3.8:1. This result is one step further toward the improvement, albeit small, of the information preserving image compression for medical applications. PMID:1913579

  4. (39) K and (23) Na relaxation times and MRI of rat head at 21.1 T.

    PubMed

    Nagel, Armin M; Umathum, Reiner; Rösler, Manuela B; Ladd, Mark E; Litvak, Ilya; Gor'kov, Peter L; Brey, William W; Schepkin, Victor D

    2016-06-01

    At ultrahigh magnetic field strengths (B0  ≥ 7.0 T), potassium ((39) K) MRI might evolve into an interesting tool for biomedical research. However, (39) K MRI is still challenging because of the low NMR sensitivity and short relaxation times. In this work, we demonstrated the feasibility of (39) K MRI at 21.1 T, determined in vivo relaxation times of the rat head at 21.1 T, and compared (39) K and sodium ((23) Na) relaxation times of model solutions containing different agarose gel concentrations at 7.0 and 21.1 T. (39) K relaxation times were markedly shorter than those of (23) Na. Compared with the lower field strength, (39) K relaxation times were up to 1.9- (T1 ), 1.4- (T2S ) and 1.9-fold (T2L ) longer at 21.1 T. The increase in the (23) Na relaxation times was less pronounced (up to 1.2-fold). Mono-exponential fits of the (39) K longitudinal relaxation time at 21.1 T revealed T1  = 14.2 ± 0.1 ms for the healthy rat head. The (39) K transverse relaxation times were 1.8 ± 0.2 ms and 14.3 ± 0.3 ms for the short (T2S ) and long (T2L ) components, respectively. (23) Na relaxation times were markedly longer (T1  = 41.6 ± 0.4 ms; T2S  = 4.9 ± 0.2 ms; T2L  = 33.2 ± 0.2 ms). (39) K MRI of the healthy rat head could be performed with a nominal spatial resolution of 1 × 1 × 1 mm(3) within an acquisition time of 75 min. The increase in the relaxation times with magnetic field strength is beneficial for (23) Na and (39) K MRI at ultrahigh magnetic field strength. Our results demonstrate that (39) K MRI at 21.1 T enables acceptable image quality for preclinical research. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27061712

  5. 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.

  6. NMR imaging of components and materials for DOE application

    SciTech Connect

    Richardson, B.R.

    1993-12-01

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

  7. NMR velocity imaging of single liquid drops

    NASA Astrophysics Data System (ADS)

    Amar, A.; Stapf, S.; Bluemich, B.

    2007-03-01

    Liquid-liquid extraction processes are often found in industrial applications when a bulk phase needs to be purified from dissolved components. The extraction strategy consists of dissolving the impurities into a second, carrier phase, with optimal performance being guaranteed by maximizing both contact interface area and mass transfer rate, in the shape of a swarm of dispersed droplets. Their buoyancy-driven flow within the continuous medium induces internal fluid motion driven by momentum transfer at the drop surface. This convective transport enhances mass transfer and the efficiency of an extraction column. However, understanding mass transfer depends on a proper description of the flow field inside and outside the drops. For that purpose, a cell was built that enables the levitation of a single drop within a counterstream of water. NMR velocity imaging was then applied to drops of different fluids to monitor the internal dynamics as a function of drop size, age, and interface tension. Vortex-type patterns in at least part of the drop were observed where their size and velocity magnitude depended on the system impurity concentration.

  8. A Demonstration of Imaging on an NMR Spectrometer.

    ERIC Educational Resources Information Center

    Hull, L. A.

    1990-01-01

    Described is a simple demonstration that relates the techniques of magnetic resonance imaging (MRI) used in medicine and nuclear magnetic resonance (NMR) spectroscopy. Included are materials, procedures, and probable results. (KR)

  9. Laundering and Deinking Applications of 1H NMR Imaging

    NASA Astrophysics Data System (ADS)

    Tutunjian, P. N.; Borchardt, J. K.; Prieto, N. E.; Raney, K. H.; Ferris, J. A.

    One-dimensional 1H NMR imaging techniques are used to visualize oil removal from fabrics and paper fibers immersed in aqueous solutions of nonionic detergents. The method provides a unique approach to the study of oil-removal kinetics in nonionic detergent systems where traditional optical techniques fail due to solution turbidity. The only requirement of the NMR experiment is the use of deuterated water in order to selectively image the hydrocarbon phase. Preliminary applications to laundering and paper deinking are discussed.

  10. NMR imaging and cryoporometry of swelling clays

    NASA Astrophysics Data System (ADS)

    Dvinskikh, Sergey V.; Szutkowski, Kosma; Petrov, Oleg V.; Furó, István.

    2010-05-01

    Compacted bentonite clay is currently attracting attention as a promising "self-sealing" buffer material to build in-ground barriers for the encapsulation of radioactive waste. It is expected to fill up the space between waste canister and surrounding ground by swelling and thus delay flow and migration from the host rock to the canister. In environmental sciences, evaluation and understanding of the swelling properties of pre-compacted clay are of uttermost importance for designing such buffers. Major goal of present study was to provide, in a non-invasive manner, a quantitative measure of bentonite distribution in extended samples during different physical processes in an aqueous environment such as swelling, dissolution, and sedimentation on the time scale from minutes to years. The propagation of the swelling front during clay expansion depending on the geometry of the confining space was also studied. Magnetic resonance imaging and nuclear magnetic resonance spectroscopy were adapted and used as main experimental techniques. With this approach, spatially resolved movement of the clay/water interface as well as clay particle distributions in gel phase can be monitored [1]. Bulk samples with swelling in a vertical tube and in a horizontal channel were investigated and clay content distribution profiles in the concentration range over five orders of magnitude and with sub-millimetre spatial resolution were obtained. Expansion rates for bulk swelling and swelling in narrow slits were compared. For sodium-exchanged montmorillonite in contact with de-ionised water, we observed a remarkable acceleration of expansion as compared to that obtained in the bulk. To characterize the porosity of the clay a cryoporometric study [2] has been performed. Our results have important implications to waste repository designs and for the assessment of its long-term performance. Further research exploring clay-water interaction over a wide variety of clay composition and water ionic

  11. 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

  12. 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.

  13. NMR imaging of fluid dynamics in reservoir core.

    PubMed

    Baldwin, B A; Yamanashi, W S

    1988-01-01

    A medical NMR imaging instrument has been modified to image water and oil in reservoir rocks by the construction of a new receiving coil. Both oil and water inside the core produced readily detectable proton NMR signals, while the rock matrix produced no signal. Because of similar T2 NMR relaxation times, the water was doped with a paramagnetic ion, Mn+2, to reduce its T2 relaxation time. This procedure enhanced the separation between the oil and water phases in the resulting images. Sequential measurements, as water imbibed into one end and oil was expelled from the other end of a core plug, produced a series of images which showed the dynamics of the fluids. For water-wet Berea Sandstone a flood front was readily observed, but some of the oil was apparently left behind in small, isolated pockets which were larger than individual pores. After several additional pore volumes of water flowed through the plug the NMR image indicated a homogeneous distribution of oil. The amount of residual oil, as determined from the ratio of NMR intensities, closely approximated the residual oil saturation of fully flooded Berea samples measured by Dean-Stark extraction. A Berea sandstone core treated to make it partially oil-wet, did not show a definitive flood front, but appeared to channel the water around the perimeter of the core plug. The relative ease with which these images were made indicates that NMR imaging can be a useful technique to follow the dynamics of oil and water through a core plug for a variety of production processes. PMID:3226235

  14. Determination of fat content in NMR images of meat

    NASA Astrophysics Data System (ADS)

    Ballerini, Lucia

    2000-12-01

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

  15. Nanoscale NMR spectroscopy and imaging of multiple nuclear species

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  16. Hepatic cancer: Correlative imaging with radioimmunodetection, NMR, and TCT

    SciTech Connect

    De Lund, F.H.; Lieber, A.; Ram, M.D.; Goldenberg, D.M.

    1984-01-01

    The purpose of this study was to compare the sensitivity of radioimmunodetection (RAID) imaging and nuclear magnetic resonance imaging in the detection of hepatic tumors. Twelve consecutive patients with metastatic (11) or primary (1) carcinoma of the liver were imaged concurrently with labeled antibodies-to-tumor antigens and by nuclear magnetic resonance. Evidence of hepatic tumors was corrected with other diagnostic procedures including TCT. Eleven patients were imaged with I-131 labeled antibodies to CEA, CSAP and one with I-131 labeled antibodies to AFP. Polyclonal, monoclonal, and Fab'/sub 2/ antibodies were used. The preparation and labeling of the antibodies have been described previously. Each patient received 2-3 mCi of labeled antibodies and was imaged at 24 to 48 hrs. Nontarget radioactivity was diminished by other radionuclides simulating nontumor distribution using a computer subtraction technique. NMR images were obtained with a 0.15T resistive instrument. In all twelve patients hepatic tumor was diagnosed by RAID. Nine of the hepatic tumors were confirmed by other methods. NMR demonstrated four positive findings in these nine. Computerized tomography detected tumors in three of the nine patients at the time of the first RAID examination, and subsequently in one more patient when RAID and NMR examinations were performed concurrently. In this series of patients the detection of hepatic cancer by RAID showed twice the sensitivity of NMR or TCT.

  17. Measurement of a wide range of intracellular sodium concentrations in erythrocytes by 23Na nuclear magnetic resonance.

    PubMed Central

    Boulanger, Y; Vinay, P; Desroches, M

    1985-01-01

    The accuracy of the 23Na nuclear magnetic resonance (NMR) method for measuring the sodium concentration in erythrocytes was tested by comparing the NMR results to those obtained by emission-flame photometry. Comparisons were made on aqueous solutions, hemolysates, gels, ghosts, and intact erythrocytes. The intra- and extracellular 23Na NMR signals were distinguished by addition of the dysprosium tripolyphosphate [Dy(PPP)7-2] shift reagent to the extracellular fluid. The intra- and extracellular volumes of ghosts and cells were determined by the isotope dilution method. Our results indicate that greater than 20% of the intracellular signal remains undetected by NMR in ghosts and cells. When the cells are hemolyzed, the amount of NMR-detectable sodium varies depending on the importance of gel formation. In hemolysates prepared by water addition, the NMR and flame photometry results are identical. The loss of signal in ghosts, cells, and undiluted hemolysates is attributed to partial binding of the Na+ ion to intracellular components, this binding being operative only when these components exist in a gel state. In a second part, 31P NMR was used to monitor the penetration of the shift reagent into the cells during incubation. Our data demonstrate that free Dy3+ can slowly accumulate inside the red cell. PMID:3986283

  18. NMR clinical imaging and spectroscopy: Its impact on nuclear medicine

    SciTech Connect

    Not Available

    1990-02-02

    This is a collection of four papers describing aspects of past and future use of nuclear magnetic resonance as a clinical diagnostic tool. The four papers are entitled (1) What Does NMR Offer that Nuclear Medicine Does Not by Jerry W. Froelich, (2) Oncological Imaging: Now, Future and Impact Jerry W. Froelich, (3) Magnetic Resonance Spectroscopy/Spectroscopic Imaging and Nuclear Medicine: Past, Present and Future by H. Cecil Charles, and (4) MR Cardiology: Now, Future and Impact by Robert J. Herfkens.

  19. NMR clinical imaging and spectroscopy: Its impact on nuclear medicine

    SciTech Connect

    Not Available

    1990-02-02

    This is a collection of four papers describing aspects of past and future use of nuclear magnetic resonance as a clinical diagnostic tool. The four papers are entitled (1) What Does NMR Offer that Nuclear Medicine Does Not? by Jerry W. Froelich, (2) Oncological Imaging: Now, Future and Impact Jerry W. Froelich, (3) Magnetic Resonance Spectroscopy/Spectroscopic Imaging and Nuclear Medicine: Past, Present and Future by H. Cecil Charles, and (4) MR Cardiology: Now, Future and Impact by Robert J. Herfkens.

  20. Mobile sensor for high resolution NMR spectroscopy and imaging

    NASA Astrophysics Data System (ADS)

    Danieli, Ernesto; Mauler, Jörg; Perlo, Juan; Blümich, Bernhard; Casanova, Federico

    2009-05-01

    In this work we describe the construction of a mobile NMR tomograph with a highly homogeneous magnetic field. Fast MRI techniques as well as NMR spectroscopy measurements were carried out. The magnet is based on a Halbach array built from identical permanent magnet blocks generating a magnetic field of 0.22 T. To shim the field inhomogeneities inherent to magnet arrays constructed from these materials, a shim strategy based on the use of movable magnet blocks is employed. With this approach a reduction of the line-width from ˜20 kHz to less than 0.1 kHz was achieved, that is by more than two orders of magnitude, in a volume of 21 cm 3. Implementing a RARE sequence, 3D images of different objects placed in this volume were obtained in short experimental times. Moreover, by reducing the sample size to 1 cm 3, sub ppm resolution is obtained in 1H NMR spectra.

  1. NMR imaging of cell phone radiation absorption in brain tissue

    PubMed Central

    Gultekin, David H.; Moeller, Lothar

    2013-01-01

    A method is described for measuring absorbed electromagnetic energy radiated from cell phone antennae into ex vivo brain tissue. NMR images the 3D thermal dynamics inside ex vivo bovine brain tissue and equivalent gel under exposure to power and irradiation time-varying radio frequency (RF) fields. The absorbed RF energy in brain tissue converts into Joule heat and affects the nuclear magnetic shielding and the Larmor precession. The resultant temperature increase is measured by the resonance frequency shift of hydrogen protons in brain tissue. This proposed application of NMR thermometry offers sufficient spatial and temporal resolution to characterize the hot spots from absorbed cell phone radiation in aqueous media and biological tissues. Specific absorption rate measurements averaged over 1 mg and 10 s in the brain tissue cover the total absorption volume. Reference measurements with fiber optic temperature sensors confirm the accuracy of the NMR thermometry. PMID:23248293

  2. NMR imaging of cell phone radiation absorption in brain tissue.

    PubMed

    Gultekin, David H; Moeller, Lothar

    2013-01-01

    A method is described for measuring absorbed electromagnetic energy radiated from cell phone antennae into ex vivo brain tissue. NMR images the 3D thermal dynamics inside ex vivo bovine brain tissue and equivalent gel under exposure to power and irradiation time-varying radio frequency (RF) fields. The absorbed RF energy in brain tissue converts into Joule heat and affects the nuclear magnetic shielding and the Larmor precession. The resultant temperature increase is measured by the resonance frequency shift of hydrogen protons in brain tissue. This proposed application of NMR thermometry offers sufficient spatial and temporal resolution to characterize the hot spots from absorbed cell phone radiation in aqueous media and biological tissues. Specific absorption rate measurements averaged over 1 mg and 10 s in the brain tissue cover the total absorption volume. Reference measurements with fiber optic temperature sensors confirm the accuracy of the NMR thermometry. PMID:23248293

  3. In situ assessment of tumor vascularity using fluorine NMR imaging.

    PubMed

    Ceckler, T L; Gibson, S L; Hilf, R; Bryant, R G

    1990-03-01

    In situ fluorine NMR imaging has been used to measure vascularity in subcutaneously implanted mammary tumors. Oxyferol, a perfluorinated blood substitute comprised of an emulsion of 25% w/v perfluorotributylamine, was used as a tracer. Following iv administration, this perfluorocarbon emulsion remains primarily in the vasculature during the image acquisition period. The distribution of the PFTA in the 19F NMR image gives a map of tissue regions with intact vascularity. This technique has been used to demonstrate decreased blood flow in necrotic regions of R3230AC mammary tumors in which vasculature had been damaged either as a result of spontaneous necrosis or by photodynamic therapy (PDT). Damage to tumor vascularity following PDT was observed prior to the development of necrosis. PMID:2325542

  4. (22)Ne(proton, gamma)(23)Na, (23)Na(proton, gamma)(24)Mg, and globular cluster abundance anomalies

    NASA Astrophysics Data System (ADS)

    Hale, Stephen Earl, Jr.

    Anticorrelations between sodium and oxygen have been observed in red giant stars in globular clusters, contrary to expectations from the standard theory of stellar evolution. It has been proposed that the 23Na is being produced through the NeNa cycle operating in layers above the main hydrogen-burning shell. The (p, γ) reactions that produce and destroy sodium have large uncertainties because of the possible influence of several resonances. We have carried out measurements of the ( 3He, d) proton-stripping reaction on 22Ne and 23Na in order to study these resonances. The upper limits on the resonance strengths of two possible resonances at Ecm = 68 and 100 keV, that account for most of the uncertainty in 22Ne( p, γ)23Na, have been reduced by factors of 10 and 4, respectively. The reaction rate of 23Na(p, γ) 24Mg has been increased dramatically with the observation of the resonance at Ecm = 136 keV with an increased strength from 10 to 6300 times stronger than the previously used value. The effect of these changes is to establish the nuclear reactions that can produce sodium in the red giant hydrogen-burning shell. The production of sodium is seen to coincide with the destruction of oxygen, through the NeNa and the CNO cycle respectively.

  5. Nuclear magnetic resonance of 23Na ions interacting with the gramicidin channel.

    PubMed Central

    Monoi, H.

    1985-01-01

    Basic nuclear magnetic resonance (NMR) features of 23Na ions bound to the gramicidin channel (packaged into lecithin liposomes) were studied. The first binding constant K1 of Na+ was not significantly dependent on channel models employed. With the two-identical-site model (Model I), K1 was 13.7 (+/- 1.4) molal-1 (in the activity basis) at 25 degrees C; when the binding of a third ion was included (Model II), it was 13.0 (+/- 2.0) molal-1. The second binding constant K2 was model dependent; it was 1.6 (+/- 0.2) and 3-4 molal-1 for Models I and II, respectively. The rate constants, k-1 and k-2, of Na+ for exit from singly and doubly loaded channels, respectively, were 8 X 10(5) s-1 less than or equal to k-1 less than or equal to 3 X 10(6) s-1 and 8 X 10(5) s-1 less than or equal to k-2 less than or equal to 1.0 X 10(7) s-1 at 25 degrees C; the lower bound represents a rough approximation of k-1. The ratio k-2/k-1 was greater than one and did not greatly exceed 20. From the competition experiment, K1 of T1+ was 5.7 (+/- 0.6) X 10(2) molal-1. The longitudinal relaxation time T1 of bound 23Na in the state of single occupancy (T 1B sing) was virtually independent of models, 0.56 (+/- 0.03) and 0.55 (+/- 0.04) ms at 25 degrees C for Models I and II, respectively. For the state of double occupancy, T1 of bound 23Na (T 1B doub) was model dependent: 0.27 (+/- 0.01) and 0.4-0.6 ms for Models I and II. The correlation time tau c of bound 23Na was 2.2 (+/- 0.2) ns at 25 degrees C for single occupancy; tau c for double occupancy was not significantly different from this value. The estimated tau c was found to involve no appreciable contribution of the exchange of 23Na between the channel and the bulk solution. Thé quadrupole coupling constant chi was 1.0 (+/- 0.1) MHz for 23Na in single occupancy; chi for double occupancy was 0.9-1.4 MHz, depending on models. A lower bound of the average quadrupole coupling constant chi alpha was 0.13-0.26 MHz at 25 degrees C for 23Na in single

  6. Time-of-flight flow imaging using NMR remote detection

    SciTech Connect

    Granwehr, Josef; Harel, Elad; Han, Song-I; Garcia, Sandra; Pines,Alex; Sen, Pabitra N.; Song, Yi-Qiao

    2005-05-05

    A time-of-flight imaging technique is introduced to visualize fluid flow and dispersion through porous media using NMR. As the fluid flows through a sample, the nuclear spin magnetization is modulated by RF pulses and magnetic field gradients to encode the spatial coordinates of the fluid. When the fluid leaves the sample, its magnetization is recorded by a second RF coil. This scheme not only facilitates a time-dependent imaging of fluid flow, it also allows a separate optimization of encoding and detection subsystems to enhance overall sensitivity. The technique is demonstrated by imaging gas flow through a porous rock.

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

    NASA Astrophysics Data System (ADS)

    Lian, Jianyu

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

  8. Exploiting Image Registration for Automated Resonance Assignment in NMR

    PubMed Central

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

    2015-01-01

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

  9. Multinuclear NMR Imaging of Fluid Phases in Berea Sandstone

    NASA Astrophysics Data System (ADS)

    Sarkar, S. N.; Dechter, J. J.; Komoroski, R. A.

    Multinuclear NMR of 7Li, 19F, and 1H has been investigated as a method for discriminating multiple fluid phases in porous rock. Good 7Li NMR images from LiCl brine in saturated Berea sandstone were obtained within a few hours at 1 × 1 × 5 mm 3 resolution using a low-TE, 3D volume imaging sequence. At 4.7 T, the 7Li T1 was 750 ms, and T2 was 10 ms. High-quality 19F and 1H images of a model fluorinated injectant (trifluorotoluene) in Berea were obtained at 0.4 × 0.4 × 3 mm 3 resolution in a few hours. Fluorine-19 imaging was found to be easier than 1H imaging due to the narrower 19F resonance and comparable T1 and T2 in Berea sandstone. Lithium-7 and 19F imaging offer alternatives for discriminating aqueous and organic phases unambiguously in flooded oil cores, especially where 1H signals for the two phases are unresolved.

  10. A double-tuned 1H/23Na dual resonator system for tissue sodium concentration measurements in the rat brain via Na-MRI

    NASA Astrophysics Data System (ADS)

    Wetterling, Friedrich; Tabbert, Martin; Junge, Sven; Gallagher, Lindsay; Mhairi Macrae, I.; Fagan, Andrew J.

    2010-12-01

    A method for quantifying the tissue sodium concentration (TSC) in the rat brain from 23Na-MR images was developed. TSC is known to change in a variety of common human diseases and holds considerable potential to contribute to their study; however, its accurate measurement in small laboratory animals has been hindered by the extremely low signal to noise ratio (SNR) in 23Na images. To address this, the design, construction and characterization of a double-tuned 1H/23Na dual resonator system for 1H-guided quantitative 23Na-MRI are described. This system comprises an SNR-optimized surface detector coil for 23Na image acquisition, and a volume resonator producing a highly homogeneous B1 field (<5% inhomogeneity) for the Na channel across the rat head. The resonators incorporated channel-independent balanced matching and tuning capabilities with active decoupling circuitry at the 23Na resonance frequency. A quantification accuracy of TSC of <10 mM was achieved in Na-images with 1.2 µl voxel resolution acquired in 10 min. The potential of the quantification technique was demonstrated in an in vivo experiment of a rat model of cerebral stroke, where the evolution of the TSC was successfully monitored for 8 h after the stroke was induced.

  11. Time resolved spectroscopic NMR imaging using hyperpolarized 129Xe.

    PubMed

    Han, S; Kühn, H; Häsing, F W; Münnemann, K; Blümich, B; Appelt, S

    2004-04-01

    We have visualized the melting and dissolution processes of xenon (Xe) ice into different solvents using the methods of nuclear magnetic resonance (NMR) spectroscopy, imaging, and time resolved spectroscopic imaging by means of hyperpolarized 129Xe. Starting from the initial condition of a hyperpolarized solid Xe layer frozen on top of an ethanol (ethanol/water) ice block we measured the Xe phase transitions as a function of time and temperature. In the pure ethanol sample, pieces of Xe ice first fall through the viscous ethanol to the bottom of the sample tube and then form a thin layer of liquid Xe/ethanol. The xenon atoms are trapped in this liquid layer up to room temperature and keep their magnetization over a time period of 11 min. In the ethanol/water mixture (80 vol%/20%), most of the polarized Xe liquid first stays on top of the ethanol/water ice block and then starts to penetrate into the pores and cracks of the ethanol/water ice block. In the final stage, nearly all the Xe polarization is in the gas phase above the liquid and trapped inside the pores. NMR spectra of homogeneous samples of pure ethanol containing thermally polarized Xe and the spectroscopic images of the melting process show that very high concentrations of hyperpolarized Xe (about half of the density of liquid Xe) can be stored or delivered in pure ethanol. PMID:15040986

  12. NMR imaging of immiscible displacements in porous media

    SciTech Connect

    Majors, P.D.; Li, P.; Peters, E.J.

    1995-12-31

    We introduce a rapid, quantitative nuclear magnetic resonance imaging (NMRI) technique to resolve and measure multiple fluid phases in porous media. Liquids are resolved on the basis of their NMR spin-spin (T{sub 2}) relaxation times, and their intensities are corrected via attenuation analysis. The spatially resolved and corrected NMRI intensities are normalized to yield fluid saturations. In-situ saturation measurements are presented for three immiscible (oil and water) displacements in the same Berea sandstone core. NMRI and effluent recovery methods were compared. T{sub 2} of the displacement fluids were observed to be sensitive to displacement conditions.

  13. Coherent Microwave Control of Ultracold 23Na 4K Molecules

    NASA Astrophysics Data System (ADS)

    Will, Sebastian A.; Park, Jee Woo; Yan, Zoe Z.; Loh, Huanqian; Zwierlein, Martin W.

    2016-06-01

    We demonstrate coherent microwave control of rotational and hyperfine states of trapped, ultracold, and chemically stable 23Na 40K molecules. Starting with all molecules in the absolute rovibrational and hyperfine ground state, we study rotational transitions in combined magnetic and electric fields and explain the rich hyperfine structure. Following the transfer of the entire molecular ensemble into a single hyperfine level of the first rotationally excited state, J =1 , we observe lifetimes of more than 3 s, comparable to those in the rovibrational ground state, J =0 . Long-lived ensembles and full quantum state control are prerequisites for the use of ultracold molecules in quantum simulation, precision measurements, and quantum information processing.

  14. Using an NMR Spectrometer to Do Magnetic Resonance Imaging: An Undergraduate Physical Chemistry Laboratory Experiment

    ERIC Educational Resources Information Center

    Steinmetz, Wayne E.; Maher, M. Cyrus

    2007-01-01

    A conventional Fourier-transform NMR spectrometer with a triple-axis gradient probe can function as a MRI imager. In this experiment students gain hands-on experience with MRI while they learn about important principles underlying the practice of NMR, such as gradients, multi-dimensional spectroscopy, and relaxation. Students image a biological…

  15. Practical design of a 4 Tesla double-tuned RF surface coil for interleaved 1H and 23Na MRI of rat brain

    NASA Astrophysics Data System (ADS)

    Alecci, M.; Romanzetti, S.; Kaffanke, J.; Celik, A.; Wegener, H. P.; Shah, N. J.

    2006-08-01

    MRI is proving to be a very useful tool for sodium quantification in animal models of stroke, ischemia, and cancer. In this work, we present the practical design of a dual-frequency RF surface coil that provides 1H and 23Na images of the rat head at 4 T. The dual-frequency RF surface coil comprised of a large loop tuned to the 1H frequency and a smaller co-planar loop tuned to the 23Na frequency. The mutual coupling between the two loops was eliminated by the use of a trap circuit inserted in the smaller coil. This independent-loop design was versatile since it enabled a separate optimisation of the sensitivity and RF field distributions of the two coils. To allow for an easy extension of this simple double-tuned coil design to other frequencies (nuclei) and dimensions, we describe in detail the practical aspects of the workbench design and MRI testing using a phantom that mimics in vivo conditions. A comparison between our independent-loop, double-tuned coil and a single-tuned 23Na coil of equal size obtained with a phantom matching in vivo conditions, showed a reduction of the 23Na sensitivity (about 28 %) because of signal losses in the trap inductance. Typical congruent 1H and 23Na rat brain images showing good SNR ( 23Na: brain 7, ventricular cerebrospinal fluid 11) and spatial resolution ( 23Na: 1.25 × 1.25 × 5 mm 3) are also reported. The in vivo SNR values obtained with this coil were comparable to, if not better than, other contemporary designs in the literature.

  16. 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.

  17. Consortium to develop the medical uses of NMR imaging, NMR spectroscopy, and positron emission tomography. Final technical report

    SciTech Connect

    Pohost, G.M.

    1998-06-01

    The goal of this work is to, perform clinically relevant studies using a new whole-body 4.1 T NMR imaging spectrometer. Initially we will develop and approach for the assessment of the severity of skeletal muscle involvement in ischemic peripheral vascular disease.

  18. Estimating radiofrequency power deposition in body NMR imaging.

    PubMed

    Bottomley, P A; Redington, R W; Edelstein, W A; Schenck, J F

    1985-08-01

    Simple theoretical estimates of the average, maximum, and spatial variation of the radiofrequency power deposition (specific absorption rate) during hydrogen nuclear magnetic resonance imaging are deduced for homogeneous spheres and for cylinders of biological tissue with a uniformly penetrating linear rf field directed axially and transverse to the cylindrical axis. These are all simple scalar multiples of the expression for the cylinder in an axial field published earlier (Med. Phys. 8, 510 (1981]. Exact solutions for the power deposition in the cylinder with axial (Phys. Med. Biol. 23, 630 (1978] and transversely directed rf field are also presented, and the spatial variation of power deposition in head and body models is examined. In the exact models, the specific absorption rates decrease rapidly and monotonically with decreasing radius despite local increases in rf field amplitude. Conversion factors are provided for calculating the power deposited by Gaussian and sinc-modulated rf pulses used for slice selection in NMR imaging, relative to rectangular profiled pulses. Theoretical estimates are compared with direct measurements of the total power deposited in the bodies of nine adult males by a 63-MHz body-imaging system with transversely directed field, taking account of cable and NMR coil losses. The results for the average power deposition agree within about 20% for the exact model of the cylinder with axial field, when applied to the exposed torso volume enclosed by the rf coil. The average values predicted by the simple spherical and cylindrical models with axial fields, the exact cylindrical model with transverse field, and the simple truncated cylinder model with transverse field were about two to three times that measured, while the simple model consisting of an infinitely long cylinder with transverse field gave results about six times that measured. The surface power deposition measured by observing the incremental power as a function of external

  19. Magnetic Particle Imaging (MPI) for NMR and MRI Researchers

    PubMed Central

    Goodwill, Patrick W.; Croft, Laura R.; Konkle, Justin J.; Lu, Kuan; Zheng, Bo; Conolly, Steven M.

    2012-01-01

    Magnetic Particle Imaging (MPI) is a new tracer imaging modality that is gaining significant interest from NMR and MRI researchers. While the physics of MPI differ substantially from MRI, it employs hardware and imaging concepts that are familiar to MRI researchers, such as magnetic excitation and detection, pulse sequences, and relaxation effects. Furthermore, MPI employs the same superparamagnetic iron oxide (SPIO) contrast agents that are sometimes used for MR angiography and are often used for MRI cell tracking studies. These SPIOs are much safer for humans than iodine or gadolinium, especially for chronic kidney disease (CKD) patients. The weak kidneys of CKD patients cannot safely excrete iodine or gadolinium, leading to increased morbidity and mortality after iodinated X-ray or CT angiograms, or after gadolinium MRA studies. Iron oxides, on the other hand, are processed in the liver, and have been shown to be safe even for CKD patients. Unlike the “black blood” contrast generated by SPIOs in MRI due to increased T2* dephasing, SPIOs in MPI generate positive, “bright blood” contrast. With this ideal contrast, even prototype MPI scanners can already achieve fast, high-sensitivity, and high-contrast angiograms with millimeter-scale resolutions in phantoms and in animals. Moreover, MPI shows great potential for an exciting array of applications, including stem cell tracking in vivo, first-pass contrast studies to diagnose or stage cancer, and inflammation imaging in vivo. So far, only a handful of prototype small-animal MPI scanners have been constructed worldwide. Hence, MPI is open to great advances, especially in hardware, pulse sequence, and nanoparticle improvements, with the potential to revolutionize the biomedical imaging field. PMID:23305842

  20. Magnetic Particle Imaging (MPI) for NMR and MRI researchers

    NASA Astrophysics Data System (ADS)

    Saritas, Emine U.; Goodwill, Patrick W.; Croft, Laura R.; Konkle, Justin J.; Lu, Kuan; Zheng, Bo; Conolly, Steven M.

    2013-04-01

    Magnetic Particle Imaging (MPI) is a new tracer imaging modality that is gaining significant interest from NMR and MRI researchers. While the physics of MPI differ substantially from MRI, it employs hardware and imaging concepts that are familiar to MRI researchers, such as magnetic excitation and detection, pulse sequences, and relaxation effects. Furthermore, MPI employs the same superparamagnetic iron oxide (SPIO) contrast agents that are sometimes used for MR angiography and are often used for MRI cell tracking studies. These SPIOs are much safer for humans than iodine or gadolinium, especially for Chronic Kidney Disease (CKD) patients. The weak kidneys of CKD patients cannot safely excrete iodine or gadolinium, leading to increased morbidity and mortality after iodinated X-ray or CT angiograms, or after gadolinium-MRA studies. Iron oxides, on the other hand, are processed in the liver, and have been shown to be safe even for CKD patients. Unlike the “black blood” contrast generated by SPIOs in MRI due to increased T2∗ dephasing, SPIOs in MPI generate positive, “bright blood” contrast. With this ideal contrast, even prototype MPI scanners can already achieve fast, high-sensitivity, and high-contrast angiograms with millimeter-scale resolutions in phantoms and in animals. Moreover, MPI shows great potential for an exciting array of applications, including stem cell tracking in vivo, first-pass contrast studies to diagnose or stage cancer, and inflammation imaging in vivo. So far, only a handful of prototype small-animal MPI scanners have been constructed worldwide. Hence, MPI is open to great advances, especially in hardware, pulse sequence, and nanoparticle improvements, with the potential to revolutionize the biomedical imaging field.

  1. Targeted Molecular Imaging of Cancer Cells Using MS2-Based (129)Xe NMR.

    PubMed

    Jeong, Keunhong; Netirojjanakul, Chawita; Munch, Henrik K; Sun, Jinny; Finbloom, Joel A; Wemmer, David E; Pines, Alexander; Francis, Matthew B

    2016-08-17

    We have synthesized targeted, selective, and highly sensitive (129)Xe NMR nanoscale biosensors using a spherical MS2 viral capsid, Cryptophane A molecules, and DNA aptamers. The biosensors showed strong binding specificity toward targeted lymphoma cells (Ramos line). Hyperpolarized (129)Xe NMR signal contrast and hyper-CEST (129)Xe MRI image contrast indicated its promise as highly sensitive hyperpolarized (129)Xe NMR nanoscale biosensor for future applications in cancer detection in vivo. PMID:27454679

  2. Miniaturized multi-coil arrays for functional planar imaging with a single-sided NMR sensor.

    PubMed

    Oligschläger, Dirk; Lehmkuhl, Sören; Watzlaw, Jan; Benders, Stefan; de Boever, Eva; Rehorn, Christian; Vossel, Manuel; Schnakenberg, Uwe; Blümich, Bernhard

    2015-05-01

    Nowadays most low-field NMR sensors, such as the single-sided Profile NMR-MOUSE®, still suffer from poor sensitivity, either resulting from low magnetic field strengths and correspondingly low NMR frequencies, or lack of sensitivity. Generally, micro-coils can improve sensitivity, but due to their small size, and thus small inductance, they are mainly used for high-field NMR. Their main application field is parallel imaging, where those coils are typically assembled to receive-only coil-arrays and increase the field-of-view. Prominent signal combination techniques such as GRAPPA and SENSE are used to combine the spatially independent NMR signals to images in order to increase acquisition speed. A decisive disadvantage of today's single-sided NMR probes is the limited accessibility for NMR imaging. Although it is possible to use flat gradient coils on top of the NMR-MOUSE® to apply imaging techniques, such images can only be recorded with very long acquisition times, excluding the NMR-MOUSE® for lateral imaging of time-dependent processes. In this study sensitivity improved micro-structured RF coils, optimized for low frequencies, and correspondingly arrays of these coils, were employed to improve sensitivity and gave access to lateral spatial resolution within the sensitive plane at several observation points at the same time. Recently developed three- and four-coil arrays were combined with a Profile NMR-MOUSE® and characterized in terms of coil coupling, noise correlation and signal combination. The three-coil array was used for lateral imaging of moisture transport in travertine rock samples and to study the one-dimensional drying of paint. PMID:25771358

  3. Miniaturized multi-coil arrays for functional planar imaging with a single-sided NMR sensor

    NASA Astrophysics Data System (ADS)

    Oligschläger, Dirk; Lehmkuhl, Sören; Watzlaw, Jan; Benders, Stefan; de Boever, Eva; Rehorn, Christian; Vossel, Manuel; Schnakenberg, Uwe; Blümich, Bernhard

    2015-05-01

    Nowadays most low-field NMR sensors, such as the single-sided Profile NMR-MOUSE®, still suffer from poor sensitivity, either resulting from low magnetic field strengths and correspondingly low NMR frequencies, or lack of sensitivity. Generally, micro-coils can improve sensitivity, but due to their small size, and thus small inductance, they are mainly used for high-field NMR. Their main application field is parallel imaging, where those coils are typically assembled to receive-only coil-arrays and increase the field-of-view. Prominent signal combination techniques such as GRAPPA and SENSE are used to combine the spatially independent NMR signals to images in order to increase acquisition speed. A decisive disadvantage of today's single-sided NMR probes is the limited accessibility for NMR imaging. Although it is possible to use flat gradient coils on top of the NMR-MOUSE® to apply imaging techniques, such images can only be recorded with very long acquisition times, excluding the NMR-MOUSE® for lateral imaging of time-dependent processes. In this study sensitivity improved micro-structured RF coils, optimized for low frequencies, and correspondingly arrays of these coils, were employed to improve sensitivity and gave access to lateral spatial resolution within the sensitive plane at several observation points at the same time. Recently developed three- and four-coil arrays were combined with a Profile NMR-MOUSE® and characterized in terms of coil coupling, noise correlation and signal combination. The three-coil array was used for lateral imaging of moisture transport in travertine rock samples and to study the one-dimensional drying of paint.

  4. Line-Integral Projection Reconstruction (LPR) with Slice Encoding Techniques: Multislice Regional Imaging in NMR Tomography.

    PubMed

    Oh, C H; Park, H W; Cho, Z H

    1984-01-01

    Line-integral projection reconstruction (LPR) in NMR imaging was found to be useful and has several advantages such as the imaging capability of objects having short T2 and compensation of phase fluctuations arising from the system instability. Although single slice LPR is found to be inefficient and poor in signal-to-noise ratio (SNR), the multislice encoded LPR method is of interest since it has a high SNR and also the capability of selected regional volume or multislice imaging. The latter, i.e., regional volume imaging capability, is a unique property of NMR imaging and offers a variety of imaging capabilities such as simultaneous multislice imaging of sagittal, transaxial, or coronal views. In this paper, we have investigated two basic forms of the multislice encoded imaging methods using LPR, i.e., Fourier and Hadamard-like encoding matrices. Applications of the methods to the experimented NMR imaging show good agreement with predicted behavior. PMID:18234626

  5. Three dimensional nuclear magnetic resonance spectroscopic imaging of sodium ions using stochastic excitation and oscillating gradients

    SciTech Connect

    Frederick, B.deB. |

    1994-12-01

    Nuclear magnetic resonance (NMR) spectroscopic imaging of {sup 23}Na holds promise as a non-invasive method of mapping Na{sup +} distributions, and for differentiating pools of Na{sup +} ions in biological tissues. However, due to NMR relaxation properties of {sup 23}Na in vivo, a large fraction of Na{sup +} is not visible with conventional NMR imaging methods. An alternate imaging method, based on stochastic excitation and oscillating gradients, has been developed which is well adapted to measuring nuclei with short T{sub 2}. Contemporary NMR imaging techniques have dead times of up to several hundred microseconds between excitation and sampling, comparable to the shortest in vivo {sup 23}Na T{sub 2} values, causing significant signal loss. An imaging strategy based on stochastic excitation has been developed which greatly reduces experiment dead time by reducing peak radiofrequency (RF) excitation power and using a novel RF circuit to speed probe recovery. Continuously oscillating gradients are used to eliminate transient eddy currents. Stochastic {sup 1}H and {sup 23}Na spectroscopic imaging experiments have been performed on a small animal system with dead times as low as 25{mu}s, permitting spectroscopic imaging with 100% visibility in vivo. As an additional benefit, the encoding time for a 32x32x32 spectroscopic image is under 30 seconds. The development and analysis of stochastic NMR imaging has been hampered by limitations of the existing phase demodulation reconstruction technique. Three dimensional imaging was impractical due to reconstruction time, and design and analysis of proposed experiments was limited by the mathematical intractability of the reconstruction method. A new reconstruction method for stochastic NMR based on Fourier interpolation has been formulated combining the advantage of a several hundredfold reduction in reconstruction time with a straightforward mathematical form.

  6. High frequency volume coils for clinical NMR imaging and spectroscopy.

    PubMed

    Vaughan, J T; Hetherington, H P; Otu, J O; Pan, J W; Pohost, G M

    1994-08-01

    A tuned transmission line resonator has been developed in theory and in practical design for the clinical NMR volume coil application at 4.1 tesla. The distributed circuit transmission line resonator was designed for high frequency, large conductive volume applications where conventional lumped element coil designs perform less efficiently. The resonator design has made use of a resonant coaxial cavity, which could be variably tuned to the Larmor frequency of interest by tunable transmission line elements. Large head- and body-sized volumes, high efficiencies, and broad tuning ranges have been shown to be characteristic of the transmission line resonator to frequencies of 500 MHz. The B1 homogeneity of the resonator has been demonstrated to be a function of the electromagnetic properties of the load itself. By numerically solving Maxwell's equations for the fully time-dependent B1 field, coil homogeneity was predicted with finite-element models of anatomic structure, and inhomogeneities corrected for. A how-to exposition of coil design and construction has been included. Simple methods of quadrature driving and double tuning the transmission line resonator have also been presented. Human head images obtained with a tuned transmission line resonator at 175 MHz have clearly demonstrated uncompromised high field advantages of signal-to-noise and spatial resolution. PMID:7968443

  7. The application of NMR imaging to the studies of enhanced oil recovery in China.

    PubMed

    Weimin, W; Dongjiang, L; Wei, L

    1996-01-01

    The advantages of the application of NMR imaging to the studies of enhanced oil recovery methods that include polymer slug flooding, combination slug flooding, and thermal soaking are described. PMID:8970120

  8. Nuclear magnetic resonance (NMR) imaging of Arnold-Chiari type I malformation with hydromyelia

    SciTech Connect

    DeLaPaz, R.L.; Brady, T.J.; Buonanno, F.S.; New, P.F.; Kistler, J.P.; McGinnis, B.D.; Pykett, I.L.; Taveras, J.M.

    1983-02-01

    Saturation recovery nuclear magnetic resonance (NMR) images and metrizamide computed tomography (CT) scans were obtained in an adult patient with a clinical history suggestive of syringomyelia. Both NMR and CT studies showed low lying cerebellar tonsils. The CT study demonstrated central cavitation of the spinal cord from the midthoracic to midcervical levels but could not exclude an intramedullary soft tissue mass at the cervico-medullary junction. The NMR images in transverse, coronal, and sagittal planes demonstrated extension of an enlarged central spinal cord cerebrospinal fluid space to the cervico-medullary junction. This was felt to be strong evidence for exclusion of an intramedullary soft tissue mass and in favor of a diagnosis of Arnold-Chiari Type I malformation with hydromyelia. The noninvasive nature of spinal cord and cervico-medullary junction evaluation with NMR is emphasized.

  9. In vivo Observation of Tree Drought Response with Low-Field NMR and Neutron Imaging

    PubMed Central

    Malone, Michael W.; Yoder, Jacob; Hunter, James F.; Espy, Michelle A.; Dickman, Lee T.; Nelson, Ron O.; Vogel, Sven C.; Sandin, Henrik J.; Sevanto, Sanna

    2016-01-01

    Using a simple low-field NMR system, we monitored water content in a living tree in a greenhouse over 2 months. By continuously running the system, we observed changes in tree water content on a scale of half an hour. The data showed a diurnal change in water content consistent both with previous NMR and biological observations. Neutron imaging experiments show that our NMR signal is primarily due to water being rapidly transported through the plant, and not to other sources of hydrogen, such as water in cytoplasm, or water in cell walls. After accounting for the role of temperature in the observed NMR signal, we demonstrate a change in the diurnal signal behavior due to simulated drought conditions for the tree. These results illustrate the utility of our system to perform noninvasive measurements of tree water content outside of a temperature controlled environment. PMID:27200037

  10. In vivo observation of tree drought response with low-field NMR and neutron imaging

    DOE PAGESBeta

    Malone, Michael W.; Yoder, Jacob; Hunter, James F.; Espy, Michelle A.; Dickman, Lee T.; Nelson, Ron O.; Vogel, Sven C.; Sandin, Henrik J.; Sevanto, Sanna

    2016-05-01

    Using a simple low-field NMR system, we monitored water content in a living tree in a greenhouse over 2 months. By continuously running the system, we observed changes in tree water content on a scale of half an hour. The data showed a diurnal change in water content consistent both with previous NMR and biological observations. Neutron imaging experiments show that our NMR signal is primarily due to water being rapidly transported through the plant, and not to other sources of hydrogen, such as water in cytoplasm, or water in cell walls. After accounting for the role of temperature inmore » the observed NMR signal, we demonstrate a change in the diurnal signal behavior due to simulated drought conditions for the tree. Lastly, these results illustrate the utility of our system to perform noninvasive measurements of tree water content outside of a temperature controlled environment.« less

  11. In vivo Observation of Tree Drought Response with Low-Field NMR and Neutron Imaging.

    PubMed

    Malone, Michael W; Yoder, Jacob; Hunter, James F; Espy, Michelle A; Dickman, Lee T; Nelson, Ron O; Vogel, Sven C; Sandin, Henrik J; Sevanto, Sanna

    2016-01-01

    Using a simple low-field NMR system, we monitored water content in a living tree in a greenhouse over 2 months. By continuously running the system, we observed changes in tree water content on a scale of half an hour. The data showed a diurnal change in water content consistent both with previous NMR and biological observations. Neutron imaging experiments show that our NMR signal is primarily due to water being rapidly transported through the plant, and not to other sources of hydrogen, such as water in cytoplasm, or water in cell walls. After accounting for the role of temperature in the observed NMR signal, we demonstrate a change in the diurnal signal behavior due to simulated drought conditions for the tree. These results illustrate the utility of our system to perform noninvasive measurements of tree water content outside of a temperature controlled environment. PMID:27200037

  12. High resolution 23Na-nuclear magnetic resonance study of stroke-prone spontaneously hypertensive rat erythrocytes.

    PubMed

    Kwan, C Y; Seo, Y; Ito, H; Murakami, M; Watari, H

    1987-06-01

    The intracellular Na+ content of washed erythrocytes from stroke-prone spontaneously hypertensive rats (SHRSP) and Wistar-Kyoto normotensive rats (WKY) was measured by a high resolution 23Na-nuclear magnetic resonance (NMR) technique using a non-permeant aqueous shift reagent, dysprosium triethylenetetramine hexaacetic acid, Dy(TTHA)3-. The initial intracellular Na+ of freshly isolated and washed erythrocytes was very low (approximately 5 mmol/l) and increased progressively with prolonged incubation in isotonic salt solution at 37 degrees C. There was no significant difference in the erythrocyte Na+ concentration between SHRSP and WKY over the entire period of measurement, nor was any difference detected in their osmotic fragility or total cellular volume, although the osmotic fragility decreased with incubation time. The high energy phosphate metabolites were also studied in the same erythrocytes by 31P-NMR. The level of intracellular ATP decreased with incubation at 37 degrees C but showed no difference between the SHRSP and WKY samples. Inclusion of 1 mmol/l ouabain in the incubation medium substantially retarded the breakdown of intracellular ATP and resulted in a concomitant increase in intracellular Na+. However, neither the ouabain-sensitive nor the ouabain-insensitive component of Na+ influx altered in SHRSP erythrocytes compared with WKY erythrocytes in paired experiments. Our results do not support the hypothesis that altered Na+ transport, resulting in an increase in erythrocyte Na+ concentration, is associated with spontaneous hypertension. PMID:3611783

  13. Gated cardiac NMR imaging and 2D echocardiography in the detection of intracardial neoplasm

    SciTech Connect

    Go, R.T.; O'Donnell, J.K.; Salcedo, E.E.; Feiglin, D.H.; Underwood, D.A.; MacIntyre, W.J.; Meaney, T.F.

    1985-05-01

    Noninvasive 2D echocardiography has replaced contrast angiography as the procedure of choice in the diagnosis of intracardiac neoplasm. The purpose of this study was to determine whether intracardiac neoplasm can be detected as well by gated cardiac NMR. Four patients with known intracardiac neoplasm previously diagnosed by 2D echocardiography had gated cardiac NMR imaging using a superconductive 0.6 Tesla magnet. All patients were performed using a Tl weighted spin echo pulse sequence with a TE of 30 msec and TR of one R-R interval. Two-dimensional planar single or multiple slice techniques were used. In one patient, imaging at different times along the R-R interval were performed for cine display. The results of the present study show detection of the intracardiac neoplasm in all four cases by gated cardiac NMR imaging and the results were comparable to 2D echocardiography. The former imaging technique showed superior spatial resolution. Despite its early stage of development, gated cardiac NMR imaging appears at least equal to 2D echocardiography in the detection of intracardiac neoplasm. The availability of multislice coupled with multiframe acquisition techniques now being developed will provide a cinematic display that will be more effective in the display of the tumor in motion within the cardiac chamber involved and facilitate visualization of the relationship of the tumor to adjacent cardiac structures.

  14. Overhauser dynamic nuclear polarization amplification of NMR flow imaging

    NASA Astrophysics Data System (ADS)

    Lingwood, Mark D.; Sederman, Andrew J.; Mantle, Mick D.; Gladden, Lynn F.; Han, Songi

    2012-03-01

    We describe the first study comparing the ability of phase shift velocity imaging and Overhauser dynamic nuclear polarization (DNP)-enhanced imaging to generate contrast for visualizing the flow of water. Prepolarization of water by the Overhauser DNP mechanism is performed in the 0.35 T fringe field of an unshielded 2.0 T non-clinical MRI magnet, followed by the rapid transfer of polarization-enhanced water to the 2.0 T imaging location. This technique, previously named remotely enhanced liquids for image contrast (RELIC), produces a continuous flow of hyperpolarized water and gives up to an -8.2-fold enhanced signal within the image with respect to thermally polarized signal at 2.0 T. Using flow through a cylindrical expansion phantom as a model system, spin-echo intensity images with DNP are compared to 3D phase shift velocity images to illustrate the complementary information available from the two techniques. The spin-echo intensity images enhanced with DNP show that the levels of enhancement provide an estimate of the transient propagation of flow, while the phase shift velocity images quantitatively measure the velocity of each imaging voxel. Phase shift velocity images acquired with and without DNP show that DNP weights velocity values towards those of the inflowing (DNP-enhanced) water, while velocity images without DNP more accurately reflect the average steady-state velocity of each voxel. We conclude that imaging with DNP prepolarized water better captures the transient path of water shortly after injection, while phase shift velocity imaging is best for quantifying the steady-state flow of water throughout the entire phantom.

  15. Elastic Scattering between Ultracold 23Na and 85Rb Atoms in the Triplet State

    NASA Astrophysics Data System (ADS)

    Hu, Qiu-Bo; Zhang, Yong-Sheng; Sun, Jin-Feng; Yu, Ke

    2011-04-01

    The elastic scattering properties between ultracold 23Na and 85Rb atoms for the triplet state (a3 Σ+u) are researched. The s-wave scattering lengths of 23Na and 85Rb are calculated by the Numerov and semiclassical method with two kinds of interatomic potentials, which are the interpolation potential and Lennard—Jones potential (LJ12,6) by the same phase Φ. Shape resonances appear clearly in the l = 5 partial waves for the a3 Σ+u state. Moreover, the s-wave scattering cross section, total cross section and energy positions of shape resonances are also discussed.

  16. Cross Polarization for 1H NMR Image Contrast in Solids

    NASA Astrophysics Data System (ADS)

    Nakai, Toshihito; Fukunaga, Yasuhiro; Nonaka, Masayuki; Matsui, Shigeru; Inouye, Tamon

    1998-09-01

    A novel1H imaging method for solids, yielding images reflecting1H-13C dipolar interactions through cross relaxation timeTIS, is presented. Phase-alternating multiple-contact cross polarization (PAMC CP) was incorporated into the magic-echo frequency-encoding imaging scheme; the PAMC CP sequence may partly but efficiently destroy the initial1H magnetization depending on theTISvalues. A theory describing the effects of the PAMC CP sequence was developed, which was used for the assessment of the sequence as well as the analysis for the experimental results. It was demonstrated that theTIS-weighted1H image and theTISmapping for a phantom, constituted of adamantane and ferrocene, can distinguish these compounds clearly.

  17. Lithium Visibility in Rat Brain and Muscle in Vivoby 7Li NMR Imaging

    NASA Astrophysics Data System (ADS)

    Komoroski, Richard A.; Pearce, John M.; Newton, Joseph E. O.

    1998-07-01

    The apparent concentration of lithium (Li)in vivowas determined for several regions in the brain and muscle of rats by7Li NMR imaging at 4.7 T with inclusion of an external standard of known concentration and visibility. The average apparent concentrations were 10.1 mM for muscle, and 4.2-5.3 mM for various brain regions under the dosing conditions used. The results were compared to concentrations determinedin vitroby high-resolution7Li NMR spectroscopy of extracts of brain and muscle tissue from the same rats. The comparison provided estimates of the7Li NMR visibility of the Li cation in each tissue region. Although there was considerable scatter of the calculated visibilities among the five rats studied, the results suggested essentially full visibility (96%) for Li in muscle, and somewhat reduced visibility (74-93%) in the various brain regions.

  18. Spatial Mapping of Flow-Induced Molecular Alignment in a Noncrystalline Biopolymer Fluid Using Double Quantum Filtered (DQF) (23)Na MRI.

    PubMed

    Pavlovskaya, Galina E; Meersmann, Thomas

    2014-08-01

    Flow-induced molecular alignment was observed experimentally in a non-liquid-crystalline bioplymeric fluid during developed tubular flow. The fluid was comprised of rigid rods of the polysaccharide xanthan and exhibited shear-thinning behavior. Without a requirement for optical transparency or the need for an added tracer, (23)Na magic angle (MA) double quantum filtered (DQF) magnetic resonance imaging (MRI) enabled the mapping of the anisotropic molecular arrangement under flow conditions. A regional net molecular alignment was found in areas of high shear values in the vicinity of the tube wall. Furthermore, the xanthan molecules resumed random orientations after the cessation of flow. The observed flow-induced molecular alignment was correlated with the rheological properties of the fluid. The work demonstrates the ability of (23)Na MA DQF magnetic resonance to provide a valuable molecular-mechanical link. PMID:26277955

  19. Two-dimensional imaging with a single-sided NMR probe.

    PubMed

    Casanova, F; Blümich, B

    2003-07-01

    A new low field unilateral NMR sensor equipped with a two-dimensional gradient coil system was built. A new NMR-MOUSE concept using a simple bar magnet instead of the classical U-shaped geometry was used to produce magnetic field profiles comparatively homogeneous in extended lateral planes defining a suitable field of view for 2D spatial localization. Slice selection along the depth direction is obtained by means of the highly constant static magnetic field gradient produced by this magnet geometry. Implementing a two-dimensional phase-encoding imaging method 2D cross sections of objects were obtained with high spatial resolution. By retuning the probe it was possible to change the depth of the selected slice obtaining a 3D imaging method. The details of the construction of the new device are presented together with imaging tests to show the quality of space encoding. PMID:12852905

  20. Creation of a strongly dipolar gas of ultracold ground-state 23 Na87 Rb molecules

    NASA Astrophysics Data System (ADS)

    Guo, Mingyang; Zhu, Bing; Lu, Bo; Ye, Xin; Wang, Fudong; Wang, Dajun; Vexiau, Romain; Bouloufa-Maafa, Nadia; Quéméner, Goulven; Dulieu, Olivier

    2016-05-01

    We report on successful creation of an ultracold sample of ground-state 23 Na87 Rb molecules with a large effective electric dipole moment. Through a carefully designed two-photon Raman process, we have successfully transferred the magneto-associated Feshbach molecules to the singlet ground state with high efficiency, obtaining up to 8000 23 Na87 Rb molecules with peak number density over 1011 cm-3 in their absolute ground-state level. With an external electric field, we have induced an effective dipole moment over 1 Debye, making 23 Na87 Rb the most dipolar ultracold particle ever achieved. Contrary to the expectation, we observed a rather fast population loss even for 23 Na87 Rb in the absolute ground state with the bi-molecular exchange reaction energetically forbidden. The origin for the short lifetime and possible ways of mitigating it are currently under investigation. Our achievements pave the way toward investigation of ultracold bosonic molecules with strong dipolar interactions. This work is supported by the Hong Kong RGC CUHK404712 and the ANR/RGC Joint Research Scheme ACUHK403/13.

  1. 1H Solid-State NMR Imaging by TREV-CRAMPS

    NASA Astrophysics Data System (ADS)

    Buszko, M. L.; Maciel, G. E.

    A proton NMR imaging experiment based on line narrowing by TREV-CRAMPS with a time-dependent magnetic field gradient has been demonstrated on a solid adamantane phantom. With the magnetic field gradient applied as 16 μs pulses in the windows of the RF pulse sequence, a spatial resolution of about 100 μm is experimentally achieved (based on linewidth and gradient strength), with a digital resolution of 40 μm, qualitatively similar to what is achieved in liquid-sample NMR imaging. The technique benefits from a favorable time average of the magnetic field gradient, relatively wide windows between the magic-echo sandwiches, and the good off-resonance line-narrowing characteristics of the TREV technique. High-resolution chemical-shift information is retained and hence potentially attainable. The low MAS rate, compared to what is used in imaging experiments in which MAS is the only line-narrowing procedure used, may be of importance if one wishes to apply 1H NMR imaging to certain types of samples, e.g., biological tissue.

  2. Nondestructive evaluation of energetic materials via NMR imaging

    NASA Astrophysics Data System (ADS)

    Iwamiya, J. H.; Sinton, S. W.; Callahan, J.; Drobny, G. P.

    The present discussion of nuclear magnetic resonance imaging (NMRI) notes that the use of standard spin-echo techniques can yield the spatial distribution of a rocket propellant or explosive charge's polymer matrix spatial distribution. For detailed NMRI studies of the solid particles embedded in the matrix, the use of either extremely large magnetic field gradients or line-narrowing methods appear promising. While the stray-field NMRI technique is currently technically difficult, it offers advantages associated with sample size and conceptual simplicity.

  3. PUPA: a pulse programming assistant for NMR imaging

    SciTech Connect

    Foxvog, D.; Li, X.; Vargas, J.E.; Bourne, J.R.; Sztipanovits, J.; Mushlin, R.; Harrison, C.G.

    1987-12-01

    The design of pulse programs for magnetic resonance imaging (MRI) experiments is tedious and complex, requiring a deep understanding of the interactions that exist between magnetic fields generated during an MRI experiment. This paper describes an intelligent system that understands how to construct the multichannel temporal sequences of pulses needed to control an MRI experiment. PUPA, the PUlse Programmers Assistant, provides assistance to a relatively naive user of MRI systems. Knowledge is coded in the form of rules and semantic networks. A natural language facility and menu system are provided for communication with the user.

  4. An instrument control and data analysis program for NMR imaging and spectroscopy

    SciTech Connect

    Roos, M.S.; Mushlin, R.A.; Veklerov, E.; Port, J.D.; Ladd, C.; Harrison, C.G.

    1988-01-01

    We describe a software environment created to support real-time instrument control and signal acquisition as well as array-processor based signal and image processing in up to five dimensions. The environment is configured for NMR imaging and in vivo spectroscopy. It is designed to provide flexible tools for implementing novel NMR experiments in the research laboratory. Data acquisition and processing operations are programmed in macros which are loaded in assembled from to minimize instruction overhead. Data arrays are dynamically allocated for efficient use of memory and can be mapped directly into disk files. The command set includes primitives for real-time control of data acquisition, scalar arithmetic, string manipulation, branching, a file system and vector operations carried out by an array processor. 6 figs.

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

    DOEpatents

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

    1984-01-01

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

  6. NMR imaging and spectroscopy of the mammalian central nervous system after heavy ion radiation

    SciTech Connect

    Richards, T.

    1984-09-01

    NMR imaging, NMR spectroscopic, and histopathologic techniques were used to study the proton relaxation time and related biochemical changes in the central nervous system after helium beam in vivo irradiation of the rodent brain. The spectroscopic observations reported in this dissertation were made possible by development of methods for measuring the NMR parameters of the rodent brain in vivo and in vitro. The methods include (1) depth selective spectroscopy using an optimization of rf pulse energy based on a priori knowledge of N-acetyl aspartate and lipid spectra of the normal brain, (2) phase-encoded proton spectroscopy of the living rodent using a surface coil, and (3) dual aqueous and organic tissue extraction technique for spectroscopy. Radiation induced increases were observed in lipid and p-choline peaks of the proton spectrum, in vivo. Proton NMR spectroscopy measurements on brain extracts (aqueous and organic solvents) were made to observe chemical changes that could not be seen in vivo. Radiation-induced changes were observed in lactate, GABA, glutamate, and p-choline peak areas of the aqueous fraction spectra. In the organic fraction, decreases were observed in peak area ratios of the terminal-methyl peaks, the N-methyl groups of choline, and at a peak at 2.84 ppM (phosphatidyl ethanolamine and phosphatidyl serine resonances) relative to TMS. With histology and Evans blue injections, blood-brain barrier alternations were seen as early as 4 days after irradiation. 83 references, 53 figures.

  7. 23Na (α,p )26Mg Reaction Rate at Astrophysically Relevant Energies

    NASA Astrophysics Data System (ADS)

    Howard, A. M.; Munch, M.; Fynbo, H. O. U.; Kirsebom, O. S.; Laursen, K. L.; Diget, C. Aa.; Hubbard, N. J.

    2015-07-01

    The production of 26Al in massive stars is sensitive to the 23Na (α,p )26Mg cross section. Recent experimental data suggest the currently recommended cross sections are underestimated by a factor of ˜40 . We present here differential cross sections for the 23Na (α,p )26Mg reaction measured in the energy range Ec .m .=1.7 - 2.5 MeV . Concurrent measurements of Rutherford scattering provide absolute normalizations that are independent of variations in target properties. Angular distributions are measured for both p0 and p1 permitting the determination of total cross sections. The results show no significant deviation from the statistical model calculations upon which the recommended rates are based. We therefore retain the previous recommendation without the increase in cross section and resulting stellar reaction rates by a factor of 40, impacting the 26Al yield from massive stars by more than a factor of 3.

  8. Creation of an Ultracold Gas of Ground-State Dipolar 23Na 87 Molecules

    NASA Astrophysics Data System (ADS)

    Guo, Mingyang; Zhu, Bing; Lu, Bo; Ye, Xin; Wang, Fudong; Vexiau, Romain; Bouloufa-Maafa, Nadia; Quéméner, Goulven; Dulieu, Olivier; Wang, Dajun

    2016-05-01

    We report the successful production of an ultracold sample of absolute ground-state 23Na 87Rb molecules. Starting from weakly bound Feshbach molecules formed via magnetoassociation, the lowest rovibrational and hyperfine level of the electronic ground state is populated following a high-efficiency and high-resolution two-photon Raman process. The high-purity absolute ground-state samples have up to 8000 molecules and densities of over 1011 cm-3 . By measuring the Stark shifts induced by external electric fields, we determined the permanent electric dipole moment of the absolute ground-state 23Na 87Rb and demonstrated the capability of inducing an effective dipole moment over 1 D. Bimolecular reaction between ground-state 23Na 87Rb molecules is endothermic, but we still observed a rather fast decay of the molecular sample. Our results pave the way toward investigation of ultracold molecular collisions in a fully controlled manner and possibly to quantum gases of ultracold bosonic molecules with strong dipolar interactions.

  9. Three New Low-Energy Resonances in the 22Ne (p ,γ )23Na Reaction

    NASA Astrophysics Data System (ADS)

    Cavanna, F.; Depalo, R.; Aliotta, M.; Anders, M.; Bemmerer, D.; Best, A.; Boeltzig, A.; Broggini, C.; Bruno, C. G.; Caciolli, A.; Corvisiero, P.; Davinson, T.; di Leva, A.; Elekes, Z.; Ferraro, F.; Formicola, A.; Fülöp, Zs.; Gervino, G.; Guglielmetti, A.; Gustavino, C.; Gyürky, Gy.; Imbriani, G.; Junker, M.; Menegazzo, R.; Mossa, V.; Pantaleo, F. R.; Prati, P.; Scott, D. A.; Somorjai, E.; Straniero, O.; Strieder, F.; Szücs, T.; Takács, M. P.; Trezzi, D.; LUNA Collaboration

    2015-12-01

    The 22Ne (p ,γ )23Na reaction takes part in the neon-sodium cycle of hydrogen burning. This cycle affects the synthesis of the elements between 20Ne and 27Al in asymptotic giant branch stars and novae. The 22Ne(p ,γ )23Na reaction rate is very uncertain because of a large number of unobserved resonances lying in the Gamow window. At proton energies below 400 keV, only upper limits exist in the literature for the resonance strengths. Previous reaction rate evaluations differ by large factors. In the present work, the first direct observations of the 22Ne (p ,γ )23Na resonances at 156.2, 189.5, and 259.7 keV are reported. Their resonance strengths are derived with 2%-7% uncertainty. In addition, upper limits for three other resonances are greatly reduced. Data are taken using a windowless 22Ne gas target and high-purity germanium detectors at the Laboratory for Underground Nuclear Astrophysics in the Gran Sasso laboratory of the National Institute for Nuclear Physics, Italy, taking advantage of the ultralow background observed deep underground. The new reaction rate is a factor of 20 higher than the recent evaluation at a temperature of 0.1 GK, relevant to nucleosynthesis in asymptotic giant branch stars.

  10. Three New Low-Energy Resonances in the ^{22}Ne(p,γ)^{23}Na Reaction.

    PubMed

    Cavanna, F; Depalo, R; Aliotta, M; Anders, M; Bemmerer, D; Best, A; Boeltzig, A; Broggini, C; Bruno, C G; Caciolli, A; Corvisiero, P; Davinson, T; di Leva, A; Elekes, Z; Ferraro, F; Formicola, A; Fülöp, Zs; Gervino, G; Guglielmetti, A; Gustavino, C; Gyürky, Gy; Imbriani, G; Junker, M; Menegazzo, R; Mossa, V; Pantaleo, F R; Prati, P; Scott, D A; Somorjai, E; Straniero, O; Strieder, F; Szücs, T; Takács, M P; Trezzi, D

    2015-12-18

    The ^{22}Ne(p,γ)^{23}Na reaction takes part in the neon-sodium cycle of hydrogen burning. This cycle affects the synthesis of the elements between ^{20}Ne and ^{27}Al in asymptotic giant branch stars and novae. The ^{22}Ne(p,γ)^{23}Na reaction rate is very uncertain because of a large number of unobserved resonances lying in the Gamow window. At proton energies below 400 keV, only upper limits exist in the literature for the resonance strengths. Previous reaction rate evaluations differ by large factors. In the present work, the first direct observations of the ^{22}Ne(p,γ)^{23}Na resonances at 156.2, 189.5, and 259.7 keV are reported. Their resonance strengths are derived with 2%-7% uncertainty. In addition, upper limits for three other resonances are greatly reduced. Data are taken using a windowless ^{22}Ne gas target and high-purity germanium detectors at the Laboratory for Underground Nuclear Astrophysics in the Gran Sasso laboratory of the National Institute for Nuclear Physics, Italy, taking advantage of the ultralow background observed deep underground. The new reaction rate is a factor of 20 higher than the recent evaluation at a temperature of 0.1 GK, relevant to nucleosynthesis in asymptotic giant branch stars. PMID:26722918

  11. Towards a study of 22Ne(pγ)23Na at LUNA

    NASA Astrophysics Data System (ADS)

    Depalo, R.; LUNA Collaboration

    2016-01-01

    The 22Ne(p,γ)23Na reaction is involved in the NeNa cycle of hydrogen burning. This cycle plays an important role for nucleosynthesis in the Red Giant Branch and Asymptotic Giant Branch phases of stellar evolution, as well as in classical novae and type Ia supernovae explosions. The 22Ne(p,γ)23Na reaction rate is highly uncertain because of a large number of resonances lying in the energy region of the Gamow peak. Several of these resonances have never been studied in either direct or indirect experiments, and only upper limits exist for their strengths. A measurement of the 2Ne(p,γ)23Na cross section is on-going at the Laboratory for Underground Nuclear Astrophysics (LUNA) in Gran Sasso. With the LUNA setup, it will be possible to study the 22Ne+p reaction inside the Gamow window. The results of a feasibility test, as well as the measurement strategy and the setup for the first experimental campaign are discussed

  12. Neuronal Tracing with Magnetic Labels: NMR Imaging Methods, Preliminary Results, and New Optimized Coils.

    NASA Astrophysics Data System (ADS)

    Ghosh, Pratik

    1992-01-01

    The investigations focussed on in vivo NMR imaging studies of magnetic particles with and within neural cells. NMR imaging methods, both Fourier transform and projection reconstruction, were implemented and new protocols were developed to perform "Neuronal Tracing with Magnetic Labels" on small animal brains. Having performed the preliminary experiments with neuronal tracing, new optimized coils and experimental set-up were devised. A novel gradient coil technology along with new rf-coils were implemented, and optimized for future use with small animals in them. A new magnetic labelling procedure was developed that allowed labelling of billions of cells with ultra -small magnetite particles in a short time. The relationships among the viability of such cells, the amount of label and the contrast in the images were studied as quantitatively as possible. Intracerebral grafting of magnetite labelled fetal rat brain cells made it possible for the first time to attempt monitoring in vivo the survival, differentiation, and possible migration of both host and grafted cells in the host rat brain. This constituted the early steps toward future experiments that may lead to the monitoring of human brain grafts of fetal brain cells. Preliminary experiments with direct injection of horse radish peroxidase-conjugated magnetite particles into neurons, followed by NMR imaging, revealed a possible non-invasive alternative, allowing serial study of the dynamic transport pattern of tracers in single living animals. New gradient coils were built by using parallel solid-conductor ribbon cables that could be wrapped easily and quickly. Rapid rise times provided by these coils allowed implementation of fast imaging methods. Optimized rf-coil circuit development made it possible to understand better the sample-coil properties and the associated trade -offs in cases of small but conducting samples.

  13. New pulse sequences for T1- and T1/T2-contrast enhancing in NMR imaging.

    PubMed

    Andreev, N K; Hakimov, A M; Idiyatullin, D S

    1998-10-01

    Improved pulse sequences DIFN (abbreviation of the words: DIFferentiation by N pulses), 90 degrees - tau1 - 180 degrees tau1 - . . . 180 degrees - tau1 with optimised time intervals tau1- for T1 measurement and contrast enhancing in NMR imaging are presented. The pulse sequences DIFN have a better sensitivity to T1 than the well-known pulse sequence SR. In contrast to the IR pulse sequence, the information given by the DIFN pulse sequence is more reliable, because the NMR signal does not change its sign. For a given time interval tau0 < or = (0.1 - 0.3) T(1) the DIFN pulse sequences serve as T1-filters. They pass the signal components with relatively short T1 < T(1) and suppress the components with relatively long T1 < T(1). The effects of the radiofrequency field inhomogeneity and inaccurate adjusting of pulse lengths are also considered. It is also proposed in this work to use the joint T1T2-contrast in NMR imaging obtained as a result of applying the DIFN pulse sequences in combination with the well-known Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence. The region of interest, where the contrast should be especially enhanced, is specified by the two times at which measurements are performed, which allow the amplitudes of pixels to reach some defined levels by spin-lattice and spin-spin relaxation. PMID:9814781

  14. NMR study in sodium-hydrogen-C{sub 60} superconductor

    SciTech Connect

    Ogata, H.; Miyajima, S.; Imaeda, K.; Inokuchi, H.

    1998-12-31

    {sup 23}Na and {sup 1}H NMR studies have been carried out for a Na{sub x}H{sub y}C{sub 60} superconductor. The peak position of the {sup 23}Na NMR spectrum exhibits discontinuous upfield shift of 30 ppm at about 250 K, indicates a first order phase transition. From the line shape of the {sup 23}Na spectrum obtained at 7 K, the quadrupole coupling constant tensor is evaluated to be {vert_bar}e{sup 2}Qq/h{vert_bar} = 3.7 MHz with the asymmetry parameter {eta} = 0.95. The {sup 1}H NMR spectrum suggests an anionic hydrogen state with weakly delocalized nature.

  15. (7)Li in situ 1D NMR imaging of a lithium ion battery.

    PubMed

    Klamor, S; Zick, K; Oerther, T; Schappacher, F M; Winter, M; Brunklaus, G

    2015-02-14

    The spatial distribution of charge carriers in lithium ion batteries during current flow is of fundamental interest for a detailed understanding of transport properties and the development of strategies for future improvements of the electrolyte-electrode interface behaviour. In this work we explored the potential of (7)Li 1D in situ NMR imaging for the identification of concentration gradients under constant current load in a battery cell. An electrochemical cell based on PTFE body and a stack of glass microfiber discs that are soaked with a technically relevant electrolyte suitable for high-temperature application and squeezed between a Li metal and a nano-Si-graphite composite electrode was assembled to acquire (7)Li 1D in situ NMR profiles with an improved NMR pulse sequence as function of time and state of charge, thereby visualizing the course of ion concentration during charge and discharge. Surface localized changes of Li concentration were attributed to processes such as solid electrolyte interphase formation or full lithiation of the composite electrode. The method allows the extraction of lithium ion transport properties. PMID:25578436

  16. Biological effects and physical safety aspects of NMR imaging and in vivo spectroscopy

    SciTech Connect

    Tenforde, T.S.; Budinger, T.F.

    1985-08-01

    An assessment is made of the biological effects and physical hazards of static and time-varying fields associated with the NMR devices that are being used for clinical imaging and in vivo spectroscopy. A summary is given of the current state of knowledge concerning the mechanisms of interaction and the bioeffects of these fields. Additional topics that are discussed include: (1) physical effects on pacemakers and metallic implants such as aneurysm clips, (2) human health studies related to the effects of exposure to nonionizing electromagnetic radiation, and (3) extant guidelines for limiting exposure of patients and medical personnel to the fields produced by NMR devices. On the basis of information available at the present time, it is concluded that the fields associated with the current generation of NMR devices do not pose a significant health risk in themselves. However, rigorous guidelines must be followed to avoid the physical interaction of these fields with metallic implants and medical electronic devices. 476 refs., 5 figs., 2 tabs.

  17. Investigating the Dissolution Performance of Amorphous Solid Dispersions Using Magnetic Resonance Imaging and Proton NMR.

    PubMed

    Tres, Francesco; Coombes, Steven R; Phillips, Andrew R; Hughes, Leslie P; Wren, Stephen A C; Aylott, Jonathan W; Burley, Jonathan C

    2015-01-01

    We have investigated the dissolution performance of amorphous solid dispersions of poorly water-soluble bicalutamide in a Kollidon VA64 polymeric matrix as a function of the drug loading (5% vs. 30% bicalutamide). A combined suite of state-of-the-art analytical techniques were employed to obtain a clear picture of the drug release, including an integrated magnetic resonance imaging UV-Vis flow cell system and 1H-NMR. Off-line 1H-NMR was used for the first time to simultaneously measure the dissolution profiles and rates of both the drug and the polymer from a solid dispersion. MRI and 1H-NMR data showed that the 5% drug loading compact erodes linearly, and that bicalutamide and Kollidon VA64 are released at approximately the same rate from the molecular dispersion. For the 30% extrudate, data indicated a slower water ingress into the compact which corresponds to a slower dissolution rate of both bicalutamide and Kollidon VA64. PMID:26378506

  18. Imaging of multiphase fluid saturation within a porous material via sodium NMR.

    PubMed

    Washburn, Kathryn E; Madelin, Guillaume

    2010-01-01

    We present in this paper a method to monitor multiphase fluid core saturation through measurement of the sodium NMR signal. In a rock core saturated with water and oil, sodium will be present only in the water phase, and therefore can be used to separate the two fluids. Two dimensional sodium images were taken to monitor the movement of brine into oil saturated rock cores. The measured fluid exchange agrees well with expected behavior from traditional core analysis methods. Indications of damage to the rock structure can be seen from the patterns of fluid imbibition. PMID:19864169

  19. NMR imaging of heavy metal absorption in alginate, immobilized cells, and kombu algal biosorbents.

    PubMed

    Nestle, N F; Kimmich, R

    1996-09-01

    In this contribution, an NMR imaging study of heavy metal absorption in alginate, immobilized-cell biosorbents, and kombu (Laminaria japonica) algal biomass is presented. This method provides the good possibility of directly monitoring the time evolution of the spatial distribution of the ions in the materials. From these results, we demonstrate that rare earth ions are absorbed with a steep reaction front that can be described very well with a modified shrinking core model, while copper ions are absorbed with a more diffuse front. PMID:18629817

  20. NMR imaging of the chest at 0.12 T: initial clinical experience with a resistive magnet.

    PubMed

    Axel, L; Kressel, H Y; Thickman, D; Epstein, D M; Edelstein, W; Bottomley, P; Redington, R; Baum, S

    1983-12-01

    The chests of 40 subjects were imaged with an experimental nuclear magnetic resonance (NMR) imager operating at a magnetic field of 0.12 T. There were six normal volunteers and 34 patients with abnormalities affecting different areas, including the chest wall, pleura, hila, mediastinum, and lung parenchyma, and including benign and malignant processes. In this initial clinical experience, NMR imaging provided useful information on the presence and extent of disease by its ability to distinguish different tissues and by the excellent demonstration of vascular structures. PMID:6606311

  1. Geometric Hall Effect of ^{23}Na Condensate in a Time- and Space-Dependent Magnetic Field

    NASA Astrophysics Data System (ADS)

    Zheng, Gong-Ping; Yang, Ling-Ling; Chang, Gao-Zhan; Wu, Zhe

    2016-04-01

    We simulate numerically the dynamics of ^{23}Na condensate in a time- and space-dependent magnetic field with a variational approach. It is shown to be an efficient method to describe the complex dynamics of the system, which may excite the breather mode, the scissor mode, and the dipole mode simultaneously. Our results agree with the experimental observations of Choi et al. (Phys Rev Lett 111:245301, 2013). We reproduce qualitatively the geometric Hall effect and resonance behavior. We also find that the condensate shows a scissor-mode-like motion, which may play the shearing force to deform the condensate and consequently leads to the dynamical nucleation of quantized vortices.

  2. Use of multi-coil parallel-gap resonators for co-registration EPR/NMR imaging

    NASA Astrophysics Data System (ADS)

    Kawada, Yuuki; Hirata, Hiroshi; Fujii, Hirodata

    2007-01-01

    This article reports experimental investigations on the use of RF resonators for continuous-wave electron paramagnetic resonance (cw-EPR) and proton nuclear magnetic resonance (NMR) imaging. We developed a composite resonator system with multi-coil parallel-gap resonators for co-registration EPR/NMR imaging. The resonance frequencies of each resonator were 21.8 MHz for NMR and 670 MHz for EPR. A smaller resonator (22 mm in diameter) for use in EPR was placed coaxially in a larger resonator (40 mm in diameter) for use in NMR. RF magnetic fields in the composite resonator system were visualized by measuring a homogeneous 4-hydroxy-2,2,6,6-tetramethyl-piperidinooxy (4-hydroxy-TEMPO) solution in a test tube. A phantom of five tubes containing distilled water and 4-hydroxy-TEMPO solution was also measured to demonstrate the potential usefulness of this composite resonator system in biomedical science. An image of unpaired electrons was obtained for 4-hydroxy-TEMPO in three tubes, and was successfully mapped on the proton image for five tubes. Technical problems in the implementation of a composite resonator system are discussed with regard to co-registration EPR/NMR imaging for animal experiments.

  3. The Dependence Of Nuclear Magnetic Resonance (NMR) Image Contrast On Intrinsic And Operator-Selectable Parameters

    NASA Astrophysics Data System (ADS)

    Wehrli, F. W.; MacFall, J. R.; Glover, G. H.

    1983-12-01

    In nuclear magnetic resonance (NMR) the image pixel value is governed by four intrinsic parameters: the spin density ρ, the spin-lattice relaxation time T1, the spin-spin relaxation time T2 and, for non-stationary spins, the flow velocity v. The extent to which the signal is weighted toward one or several parameters is related to the history of the spin system preceding the detection pulse. In the present work T1 and T2 were determined in vivo for several regions in the CNS from inversion-recovery (T1) And multiple-echo (T2) images, using least-squares fitting procedures. From averaged values of T1 and T2 in grey matter, white matter and CSF, the signal intensity was calculated on the basis of the Bloch equations and plotted as a function of the intrinsic parameters for the three most common imaging pulse sequences. These data are in excellent agreement with images, recorded from normal volunteers on an experimental whole-body imaging system operating at 12.8 MHz (0.3T). The graphical presentation of contrast further will provide the radiologist with a straightforward tool for image interpretation.

  4. Creating Fermionic Ground State Molecules of 23Na40K with Strong Dipolar Interactions

    NASA Astrophysics Data System (ADS)

    Park, Jee; Wu, Cheng-Hsun; Schloss, Jennifer; Will, Sebastian; Zwierlein, Martin

    2013-05-01

    In our experiment, we work towards creating fermionic ground state molecules of 23Na40K with strong dipolar interactions. These molecules will be chemically stable in the rovibrational ground state, and will carry a large induced dipole moment of 2.72 Debye. Building up on our previous work, we have done photoassociation spectroscopy on the 23Na-40K mixture in order to understand the molecular excited state potentials and identify possible intermediate states for efficient STIRAP transfer of Feshbach molecules down to the absolute rovibrational ground state. In addition, our recent effort in doing two-photon spectroscopy to locate the absolute rovibrational ground state will be presented. Our work paves the way towards creating stable dipolar quantum gases, which will open up new avenues to quantum many-body phases with intriguing properties such as supersolidity and topological phases. This work was supported by the NSF, AFOSR-MURI and -PECASE, ARO-MURI, ONR YIP, DARPA YFA, a grant from the Army Research Office with funding from the DARPA OLE program and the David and Lucille Packard Foundation.

  5. Direct measurement of the 22Ne(p,γ)23Na reaction cross section at LUNA

    NASA Astrophysics Data System (ADS)

    Ferraro, Federico; LUNA Collaboration

    2016-06-01

    The 22Ne(p, γ)23Na reaction takes part in the NeNa cycle of hydrogen burning, influencing the production of the elements between 20Ne and 27Al in red giant stars, asymptotic giant stars and classical novae. The 22Ne(p,γ)27Na reaction rate is very uncertain because of a large number of tentative resonances in the Gamow window, where only upper limits were quoted in literature. A direct measurement of the 22Ne(p, γ)23Na reaction cross section has been carried out at LUNA using a windowless differential-pumping gas target with two high- purity germanium (HPGe) detectors. A new measurement with a 4π bismuth germanate (BGO) summing detector is ongoing. During the HPGe phase of the experiment the strengths of the resonances at 156.2 keV, 189.5 keV and 259.7 keV have been directly measured for the first time and their contribution to the reaction rate has been calculated. The decay scheme of the newly discovered resonances has been established as well and some improved upper limits on the unobserved resonances have been put. The BGO detector with its 70% γ-detection efficiency allows to measure the cross section at lower energy. In order to further investigate the resonances at 71 keV and 105 keV and the direct-capture component, the data taking is ongoing.

  6. Rotational Spectroscopy on Ultracold 23 Na40 K Ground State Molecules

    NASA Astrophysics Data System (ADS)

    Will, Sebastian; Park, Jee Woo; Yan, Zoe; Loh, Huanqian; Zwierlein, Martin

    2016-05-01

    Ultracold molecules with controllable dipolar long-range interactions will open up new routes for quantum simulation and the creation of novel states of matter. In particular, the molecules' rich internal degrees of freedom allow for versatile control of intermolecular interactions by applying static electric and microwave fields. Starting from an ultracold, spin-polarized ensemble of trapped fermionic 23 Na40 K molecules in the absolute ground state, we perform microwave spectroscopy on the first rotationally excited state for a range of magnetic and electric fields. Extracting the rotational and hyperfine coupling constants, we comprehensively understand the observed spectra. Following the coherent transfer of the entire ensemble of chemically stable 23 Na40 K molecules to the first rotationally excited state, we observe a lifetime of more than 3 sec, comparable to the lifetime in the rovibrational ground state. The collisional stability of excited rotational states opens up intriguing prospects for the control of intermolecular van-der-Waals interactions via electric fields.

  7. Solid-state C-13 and H-1 NMR imaging stdies of the accelerated-sulfur cured high vinyl polybutadiene. [NMR (nuclear magnetic resonance)

    SciTech Connect

    Rana, M.A.

    1993-01-01

    Solid-state [sup 13]C NMR and [sup 1]H Imaging methods have been used to follow the progress of accelerated-sulfur vulcanization of unfilled high vinyl polybutadiene. Different NMR pulse sequences have been used to characterize the micro-network structures present in the bulk of the finally cured rubber samples. These studies were made as a function of formulation and processing variables. The time-resolved, integrated rubber network. Mono-sulfidic as well as the residual accelerator fragments were differentiated from the polysulfidic crosslinks in a finally cured material. Dynamic studies of these network structures were made using spin-spin relaxation (T[sub 2c]) measurements. The activation energies calculated based on T[sub 2] were used to verify different carbons, directly attached to the sulfur atoms. A swelling method based on Flory-Rehner's equation was also used to determine the crosslink densities and the number-average molecular weight between the nodal junctions in different formulations. Different spatially resolved structural features have been detected in the swollen samples using NMR imaging method. The voids, no-voids and other impurities were differentiated on the basis of magnetic susceptibility differences. Cyclohexane was used as a swelling solvent to probe the morphological defects in these materials. The T[sub 2]-weighted images were used to evaluate the crosslink densities in different samples. The quantitative estimations based on histogram was also employed to determine the average volume per crosslink region. The contrast based on H-1 spin-density or mobility was highlighted in T[sub 2]-weighted images. The variations were found to be closely related to variation in both concentration and mobility of the network.

  8. 23Na and 39K nuclear magnetic resonance studies of perfused rat hearts. Discrimination of intra- and extracellular ions using a shift reagent.

    PubMed Central

    Pike, M M; Frazer, J C; Dedrick, D F; Ingwall, J S; Allen, P D; Springer, C S; Smith, T W

    1985-01-01

    High-resolution 23Na and 39K nuclear magnetic resonance (NMR) spectra of perfused, beating rat hearts have been obtained in the absence and presence of the downfield shift reagent Dy(TTHA)3- in the perfusing medium. Evidence indicates that Dy(TTHA)3- enters essentially all extracellular spaces but does not enter intracellular spaces. It can thus be used to discriminate the resonances of the ions in these spaces. Experiments supporting this conclusion include interventions that inhibit the Na+/K+ pump such as the inclusion of ouabain in and the exclusion of K+ from the perfusing medium. In each of these experiments, a peak corresponding to intracellular sodium increased in intensity. In the latter experiment, the increase was reversed when the concentration of K+ in the perfusing medium was returned to normal. When the concentration of Ca2+ in the perfusing medium was also returned to normal, the previously quiescent heart resumed beating. In the beating heart where the Na+/K+ pump was not inhibited, the intensity of the intracellular Na+ resonance was less than 20% of that expected. Although the data are more sparse, the NMR visibility of the intracellular K+ signal appears to be no more than 20%. PMID:4016206

  9. Point sensitive NMR imaging system using a magnetic field configuration with a spatial minimum

    DOEpatents

    Eberhard, Philippe H.

    1985-01-01

    A point-sensitive NMR imaging system (10) in which a main solenoid coil (11) produces a relatively strong and substantially uniform magnetic field and a pair of perturbing coils (PZ1 and PZ2) powered by current in the same direction superimposes a pair of relatively weak perturbing fields on the main field to produce a resultant point of minimum field strength at a desired location in a direction along the Z-axis. Two other pairs of perturbing coils (PX1, PX2; PY1, PY2) superimpose relatively weak field gradients on the main field in directions along the X- and Y-axes to locate the minimum field point at a desired location in a plane normal to the Z-axes. An RF generator (22) irradiates a tissue specimen in the field with radio frequency energy so that desired nuclei in a small volume at the point of minimum field strength will resonate.

  10. Point sensitive NMR imaging system using a magnetic field configuration with a spatial minimum

    DOEpatents

    Eberhard, P.H.

    A point-sensitive NMR imaging system in which a main solenoid coil produces a relatively strong and substantially uniform magnetic field and a pair of perturbing coils powered by current in the same direction superimposes a pair of relatively weak perturbing fields on the main field to produce a resultant point of minimum field strength at a desired location in a direction along the Z-axis. Two other pairs of perturbing coils superimpose relatively weak field gradients on the main field in directions along the X- and Y-axes to locate the minimum field point at a desired location in a plane normal to the Z-axes. An rf generator irradiates a tissue specimen in the field with radio frequency energy so that desired nuclei in a small volume at the point of minimum field strength will resonate.

  11. Neutron Elastic and Inelastic Scattering Cross Sections on ^NatFe and ^23Na

    NASA Astrophysics Data System (ADS)

    Kersting, Luke; Lueck, Collin J.; Hicks, S. F.; Crider, B. P.; McEllistrem, M. T.; Peters, E. E.; Vanhoy, J. R.

    2010-10-01

    Neutron elastic and inelastic scattering angular distributions from ^NatFe and ^23Na at incident neutron energies of 3.57 and 3.81 MeV have been measured at the University of Kentucky 7 MV Van de Graaff laboratory using neutron time-of-flight techniques. The neutron beam was produced using the ^3H(p,n)He^3reaction. The scattered neutrons were detected at angles between 20 and 150 in 10 intervals with a hexafluorbenzene detector located approximately 3 m from the scattering samples. Neutron scattering differential cross sections were deduced. These cross sections and their uncertainties are important for understanding neutron-induced reactions in fission reactors and are important for fission reactor criticality calculations.

  12. NMR imaging and hydrodynamic analysis of neutrally buoyant non-Newtonian slurry flows

    SciTech Connect

    Bouillard, J.X.; Sinton, S.W.

    1995-02-01

    The flow of solids loaded suspension in cylindrical pipes has been the object of intense experimental and theoretical investigations in recent years. These types of flows are of great interest in chemical engineering because of their important use in many industrial manufacturing processes. Such flows are for example encountered in the manufacture of solid-rocket propellants, advanced ceramics, reinforced polymer composites, in heterogenous catalytic reactors, and in the pipeline transport of liquid-solids suspensions. In most cases, the suspension microstructure and the degree of solids dispersion greatly affect the final performance of the manufactured product. For example, solid propellant pellets need to be extremely-well dispersed in gel matrices for use as rocket engine solid fuels. The homogeneity of pellet dispersion is critical to allow good uniformity of the burn rate, which in turn affects the final mechanical performance of the engine. Today`s manufacturing of such fuels uses continuous flow processes rather than batch processes. Unfortunately, the hydrodynamics of such flow processes is poorly understood and is difficult to assess because it requires the simultaneous measurements of liquid/solids phase velocities and volume fractions. Due to the recent development in pulsed Fourier Transform NMR imaging, NMR imaging is now becoming a powerful technique for the non intrusive investigation of multi-phase flows. This paper reports and exposes a state-of-the-art experimental and theoretical methodology that can be used to study such flows. The hydrodynamic model developed for this study is a two-phase flow shear thinning model with standard constitutive fluid/solids interphase drag and solids compaction stresses. this model shows good agreement with experimental data and the limitations of this model are discussed.

  13. DUAL FREQUENCY RESONATOR FOR 1.2 GHZ EPR/16.2 MHZ NMR CO-IMAGING

    PubMed Central

    Petryakov, Sergey; Samouilov, Alexandre; Kesselring, Eric; Caia, George L.; Sun, Ziqi; Zweier, Jay L.

    2010-01-01

    The development of a dual frequency resonator that enables both EPR and proton NMR imaging within the same resonator, magnet and gradient system is described. A novel design allows the same resonator to perform both EPR and proton NMR operation without moving resonator cables or switches. The resonator is capable of working at frequencies of 16.18 MHz for proton NMR and 1.2 GHz for EPR and is optimized for isolated rat heart experiments, measuring 22 mm in inner diameter and 19 mm in length. In EPR mode, the resonator functions as a one loop two gap resonator, electrically coupled through a half wavelength inverter. In NMR mode, it functions a single turn coil. Using the same loop for both modalities maximizes filling factor at both frequencies. Placing the tuning and switching controls away from the resonator prevents any inadvertent movement that would cause errors of EPR and NMR co-imaging registration. The resonator enabled good quality EPR and proton MRI of isolated rat hearts with precise registration. PMID:20434379

  14. Low-Energy resonances in the 22Ne(p,γ)23Na reaction directly observed at LUNA

    NASA Astrophysics Data System (ADS)

    Depalo, Rosanna; LUNA Collaboration

    2016-04-01

    The neon-sodium cycle of hydrogen burning influences the synthesis of the elements between 20Ne and 27Al in AGB stars and classical novae explosions. The 22Ne(p,γ)23Na reaction rate is very uncertain because of a large number of unobserved resonances lying in the Gamow window. A new direct study of the 22Ne(p,γ)23Na reaction has been performed at the Laboratory for Underground Nuclear Astrophysics (LUNA) using a windowless gas target and two HPGe detectors. Several resonances have been observed for the first time in a direct experiment.

  15. Cryptate 13C and 23Na nuclear magnetic relaxation as a probe of counterion dynamics in aqueous polyacrylate solutions

    NASA Astrophysics Data System (ADS)

    Van Der Maarel, J. R. C.; Van Duijn, D.; De Bleijser, J.; Leyte, J. C.

    1987-03-01

    In a series of fully alkali neutralized polyacrylate solutions the counterions are included by a macrobicyclic ligand (cryptand) to form a well-defined coordination shell. Vapor pressure experiments show the polyacrylate-cryptate system to behave osmotically as an ordinary polyelectrolyte solution. Cryptate 13C and 23Na relaxation show that the influence of polyions on the counter-ion reorientational mobility is moderate. The main 23Na relaxation mechanism is found to be the fluctuating electric field gradient caused by the surrounding ligand.

  16. NMR imaging of fluid exchange between macropores and matrix in eogenetic karst

    USGS Publications Warehouse

    Florea, L.J.; Cunningham, K.J.; Altobelli, S.

    2009-01-01

    Sequential time-step images acquired using nuclear magnetic resonance (NMR) show the displacement of deuterated water (D2O) by fresh water within two limestone samples characterized by a porous and permeable limestone matrix of peloids and ooids. These samples were selected because they have a macropore system representative of some parts of the eogenetic karst limestone of the Biscayne Aquifer in southeastern Florida. The macroporosity, created by the trace fossil Ophiomorpha, is principally well connected and of centimeter scale. These macropores occur in broadly continuous stratiform zones that create preferential flow layers within the hydrogeologic units of the Biscayne. This arrangement of porosity is important because in coastal areas, it could produce a preferential pathway for salt water intrusion. Two experiments were conducted in which samples saturated with D2O were placed in acrylic chambers filled with fresh water and examined with NMR. Results reveal a substantial flux of fresh water into the matrix porosity with a simultaneous loss of D 2O. Specifically, we measured rates upward of 0.001 mL/h/g of sample in static conditions, and perhaps as great as 0.07 mL/h/g of sample when fresh water continuously flows past a sample at velocities less than those found within stressed areas of the Biscayne. These experiments illustrate how fresh water and D2O, with different chemical properties, migrate within one type of matrix porosity found in the Biscayne. Furthermore, these experiments are a comparative exercise in the displacement of sea water by fresh water in the matrix of a coastal, karst aquifer since D2O has a greater density than fresh water. ?? 2008 National Ground Water Association.

  17. Measurement of regional cerebral blood flow in cat brain using intracarotid 2H2O and 2H NMR imaging

    SciTech Connect

    Detre, J.A.; Subramanian, V.H.; Mitchell, M.D.; Smith, D.S.; Kobayashi, A.; Zaman, A.; Leigh, J.S. Jr. )

    1990-05-01

    Cerebral blood flow (CBF) was measured in cat brain in vivo at 2.7 T using 2H NMR to monitor the washout of deuterated saline injected into both carotid arteries via the lingual arteries. In anesthetized cats, global CBF varied directly with PaCO{sub 2} over a range of 20-50 mm Hg, and the corresponding global CBF values ranged from 25 to 125 ml.100 g-1.min-1. Regional CBF was measured in a 1-cm axial section of cat brain using intracarotid deuterated saline and gradient-echo 2H NMR imaging. Blood flow images with a maximum pixel resolution of 0.3 x 0.3 x 1.0 cm were generated from the deuterium signal washout at each pixel. Image derived values for CBF agreed well with other determinations, and decreased significantly with hypocapnia.

  18. Differential Cross Sections for Neutron Elastic and Inelastic Scattering on 23Na

    NASA Astrophysics Data System (ADS)

    Vanhoy, J. R.; Hicks, S. F.; Chakraborty, A.; Champine, B. R.; Combs, B.; Crider, B. P.; Kersting, L. J.; Kumar, A.; Lueck, C. J.; McDonough, P. J.; McEllistrem, M. T.; Peters, E. E.; Prados-Estévez, F. M.; Sidwell, L.; Sigillito, A.; Watts, D. W.; Yates, S. W.

    2014-03-01

    Measurements of neutron elastic and inelastic scattering from 23Na have been performed for sixteen incident neutron energies above 1.5 MeV with the 7-MV University of Kentucky Accelerator using the 3H(p,n) reaction as the neutron source. These measurements were complemented by γ-ray excitation functions using the (n,n'γ) reaction. The time-of-flight technique is employed for background reduction in both neutron and γ- ray measurements and for determining the energy of the scattered neutrons. Cross section determinations support fuel cycle and structural materials research and development. Previous reaction model evaluations [1] relied primarily on total cross sections and four (n,n0) and (n,n1) angular distributions in the En = 5 to 9 MeV range. The inclusion of more inelastic channels at lower neutron energies provides additional information on direct couplings between elastic and inelastic scattering as a function of angular momentum transfer. Reaction model calculations examining direct collective and statistical properties were performed.

  19. Measurement of (23)Na(n,2n) cross section in well-defined reactor spectra.

    PubMed

    Košťál, Michal; Švadlenková, Marie; Baroň, Petr; Milčák, Ján; Mareček, Martin; Uhlíř, Jan

    2016-05-01

    The present paper aims to compare the calculated and experimental reaction rates of (23)Na(n,2n)(22)Na in a well-defined reactor spectra of a special core assembled in the LR-0 reactor. The experimentally determined reaction rate, derived using gamma spectroscopy of irradiated NaF sample, is used for average cross section determination. The resulting value averaged in spectra is 0.91±0.02µb. This cross-section is important as it is included in International Reactor Dosimetry and Fusion File and is also relevant to the correct estimation of long-term activity of Na coolant in Sodium Fast Reactors. The calculations were performed with the MCNP6 code using ENDF/B-VII.0, JEFF-3.1, JEFF-3.2, JENDL-3.3, JENDL-4, ROSFOND-2010 and CENDL-3.1 nuclear data libraries. Generally the best C/E agreement, within 2%, was found using the ROSFOND-2010 data set, whereas the worst, as high as 40%, was found using the ENDF/B-VII.0. PMID:26894323

  20. Long Hyperfine Coherence Time of Ultracold Fermionic 23 Na40 K Molecules

    NASA Astrophysics Data System (ADS)

    Park, Jee Woo; Yan, Zoe; Loh, Huanqian; Will, Sebastian; Zwierlein, Martin

    2016-05-01

    Ultracold molecules created and trapped at sub uK temperatures allow the full control of the molecule's external and internal degrees of freedom down to a single hyperfine state. In particular, an ensemble of molecules all initialized in a single rotational and hyperfine state can be prepared and be coherently addressed using microwave fields. In this talk, we report on the observation of long coherence time between two hyperfine states of fermionic 23 Na40 K molecules in the ro-vibronic ground state (v = 0 , J = 0). A direct two-photon microwave transition via the J = 1 state is used to prepare a superposition of two lowest hyperfine states of J = 0 , and we perform Ramsey spectroscopy as a direct probe of phase coherence between these states. The fermionic nature of the molecules and the lack of electronic angular momentum in the ro-vibronic ground state heavily suppress the decoherence from collisions and external fields, respectively, and we observe long coherence times upto 0.5 sec for this hyperfine superposition state. The observed long coherence time is a crucial step for applications of trapped dipolar molecules in quantum information processing schemes.

  1. NMR imaging of chitosan and carboxymethyl starch tablets: swelling and hydration of the polyelectrolyte complex.

    PubMed

    Wang, Y J; Assaad, E; Ispas-Szabo, P; Mateescu, M A; Zhu, X X

    2011-10-31

    The hydration and swelling properties of the tablets made of chitosan, carboxymethyl starch, and a polyelectrolyte complex of these two polysaccharides have been studied by NMR imaging. We studied the effect of pH and ionic strength on the swelling of the tablets and on the diffusion of fluid into the tablets in water and simulated physiological fluids. The pH value of the fluids exerts a more significant effect than their ionic strengths on the swelling of the tablets. The tablets are compared also with those made of cross-linked high amylose starch. The formation of complex helps to keep the integrity of the tablets in various media and render a slow and restricted swelling similar to that of the tablets of the cross-linked high amylase starch, which is significantly lower than the swelling of chitosan and of carboxymethyl starch. The capacities to modulate the release rate of drugs in different media are discussed by comparing the matrices and evaluating the preparation process of the complex. A sustained release of less soluble drugs such as aspirin in gastrointestinal fluids can be provided by the complex, due to the ionic interaction and hydrogen bonding between the drug and the biopolymer complex. PMID:21864660

  2. High resolution measurement of neutron inelastic scattering cross-sections for 23Na

    NASA Astrophysics Data System (ADS)

    Rouki, C.; Archier, P.; Borcea, C.; De Saint Jean, C.; Drohé, J. C.; Kopecky, S.; Moens, A.; Nankov, N.; Negret, A.; Noguère, G.; Plompen, A. J. M.; Stanoiu, M.

    2012-04-01

    The neutron inelastic scattering cross-section of 23Na has been measured in response to the relevant request of the OECD-NEA High Priority Request List, which requires a target uncertainty of 4% in the energy range up to 1.35 MeV for the development of sodium-cooled fast reactors. The measurement was performed at the GELINA facility with the Gamma Array for Inelastic Neutron Scattering (GAINS), featuring eight high purity germanium detectors. The setup is installed at a 200 m flight path from the neutron source and provides high resolution measurements using the (n,n'γ)-technique. The sample was an 80 mm diameter metallic sodium disk prepared at IRMM. Transitions up to the seventh excited state were observed and the differential gamma cross-sections at 110° and 150° were measured, showing mostly isotropic gamma emission. From these the gamma production, level and inelastic cross-sections were determined for neutron energies up to 3838.9 keV. The results agree well with the existing data and the evaluated nuclear data libraries in the low energies, and provide new experimental points in the little studied region above 2 MeV. Following a detailed review of the methodology used for the gamma efficiency calibrations and flux normalization of GAINS data, an estimated total uncertainty of 2.2% was achieved for the inelastic cross-section integrals over the energy ranges 0.498-1.35 MeV and 1.35-2.23 MeV, meeting the required targets.

  3. Accurate Characterization of Ion Transport Properties in Binary Symmetric Electrolytes Using In Situ NMR Imaging and Inverse Modeling.

    PubMed

    Sethurajan, Athinthra Krishnaswamy; Krachkovskiy, Sergey A; Halalay, Ion C; Goward, Gillian R; Protas, Bartosz

    2015-09-17

    We used NMR imaging (MRI) combined with data analysis based on inverse modeling of the mass transport problem to determine ionic diffusion coefficients and transference numbers in electrolyte solutions of interest for Li-ion batteries. Sensitivity analyses have shown that accurate estimates of these parameters (as a function of concentration) are critical to the reliability of the predictions provided by models of porous electrodes. The inverse modeling (IM) solution was generated with an extension of the Planck-Nernst model for the transport of ionic species in electrolyte solutions. Concentration-dependent diffusion coefficients and transference numbers were derived using concentration profiles obtained from in situ (19)F MRI measurements. Material properties were reconstructed under minimal assumptions using methods of variational optimization to minimize the least-squares deviation between experimental and simulated concentration values with uncertainty of the reconstructions quantified using a Monte Carlo analysis. The diffusion coefficients obtained by pulsed field gradient NMR (PFG-NMR) fall within the 95% confidence bounds for the diffusion coefficient values obtained by the MRI+IM method. The MRI+IM method also yields the concentration dependence of the Li(+) transference number in agreement with trends obtained by electrochemical methods for similar systems and with predictions of theoretical models for concentrated electrolyte solutions, in marked contrast to the salt concentration dependence of transport numbers determined from PFG-NMR data. PMID:26247105

  4. 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.

  5. Exploring the {sup 22}Ne(p,γ){sup 23}Na reaction at LUNA and at HZDR

    SciTech Connect

    Cavanna, Francesca; Collaboration: LUNA Collaboration

    2014-05-09

    The {sup 22}Ne(p,γ){sup 23}Na reaction is involved in the hydrogen burning NeNa cycle. This determines the nucleosynthesis of the Ne and Na isotopes in the Red Giant Branch and Asymptotic Giant Branch phases of stellar evolution. In the energy range relevant for astrophysics (20 keV < E < 600 keV), the {sup 22}Ne(p,γ){sup 23}Na reaction rate is highly uncertain because of the contribution of a large number of resonances never measured directly. A related study is under preparation at the Laboratory for Underground Nuclear Astrophysics (LUNA), in the Gran Sasso National Laboratory, and it will cover the energy range 100 keV < E < 400 keV. Meanwhile, a measurement at higher energies (i.e. 436 keV) has been carried out at the Tandetron accelerator of the HZDR (Helmholtz Zentrum Dresden Rossendorf) in Germany. Some preliminary results will be presented.

  6. Discrimination of intra- and extracellular 23Na + signals in yeast cell suspensions using longitudinal magnetic resonance relaxography

    NASA Astrophysics Data System (ADS)

    Zhang, Yajie; Poirer-Quinot, Marie; Springer, Charles S.; Balschi, James A.

    2010-07-01

    This study tested the ability of MR relaxography (MRR) to discriminate intra- (Nai+) and extracellular (Nae+)23Na + signals using their longitudinal relaxation time constant ( T1) values. Na +-loaded yeast cell ( Saccharomyces cerevisiae) suspensions were investigated. Two types of compartmental 23Na +T1 differences were examined: a selective Nae+T1 decrease induced by an extracellular relaxation reagent (RR e), GdDOTP 5-; and, an intrinsic T1 difference. Parallel studies using the established method of 23Na MRS with an extracellular shift reagent (SR e), TmDOTP 5-, were used to validate the MRR measurements. With 12.8 mM RR e, the 23Nae+T1 was 2.4 ms and the 23Nai+T1 was 9.5 ms (9.4T, 24 °C). The Na + amounts and spontaneous efflux rate constants were found to be identical within experimental error whether measured by MRR/RR e or by MRS/SR e. Without RR e, the Na +-loaded yeast cell suspension 23Na MR signal exhibited two T1 values, 9.1 (±0.3) ms and 32.7 (±2.3) ms, assigned to 23Nai+ and 23Nae+, respectively. The Nai+ content measured was lower, 0.88 (±0.06); while Nae+ was higher, 1.43 (±0.12) compared with MRS/SR e measures on the same samples. However, the measured efflux rate constant was identical. T1 MRR potentially may be used for Nai+ determination in vivo and Na + flux measurements; with RR e for animal studies and without RR e for humans.

  7. Computational Diffusion Magnetic Resonance Imaging Based on Time-Dependent Bloch NMR Flow Equation and Bessel Functions.

    PubMed

    Awojoyogbe, Bamidele O; Dada, Michael O; Onwu, Samuel O; Ige, Taofeeq A; Akinwande, Ninuola I

    2016-04-01

    Magnetic resonance imaging (MRI) uses a powerful magnetic field along with radio waves and a computer to produce highly detailed "slice-by-slice" pictures of virtually all internal structures of matter. The results enable physicians to examine parts of the body in minute detail and identify diseases in ways that are not possible with other techniques. For example, MRI is one of the few imaging tools that can see through bones, making it an excellent tool for examining the brain and other soft tissues. Pulsed-field gradient experiments provide a straightforward means of obtaining information on the translational motion of nuclear spins. However, the interpretation of the data is complicated by the effects of restricting geometries as in the case of most cancerous tissues and the mathematical concept required to account for this becomes very difficult. Most diffusion magnetic resonance techniques are based on the Stejskal-Tanner formulation usually derived from the Bloch-Torrey partial differential equation by including additional terms to accommodate the diffusion effect. Despite the early success of this technique, it has been shown that it has important limitations, the most of which occurs when there is orientation heterogeneity of the fibers in the voxel of interest (VOI). Overcoming this difficulty requires the specification of diffusion coefficients as function of spatial coordinate(s) and such a phenomenon is an indication of non-uniform compartmental conditions which can be analyzed accurately by solving the time-dependent Bloch NMR flow equation analytically. In this study, a mathematical formulation of magnetic resonance flow sequence in restricted geometry is developed based on a general second order partial differential equation derived directly from the fundamental Bloch NMR flow equations. The NMR signal is obtained completely in terms of NMR experimental parameters. The process is described based on Bessel functions and properties that can make it

  8. Use of NMR Imaging to Determine the Diffusion Coefficient of Water in Bio-based Hydrogels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The diffusion of liquid in a hydrogel material is a fundamental property which must be controlled in order to create effective delivery systems for the agricultural and pharmaceutical industries. NMR spectroscopy has been used to determine the diffusion of water and deuterium oxide in a bio-based h...

  9. Organ specific mapping of in vivo redox state in control and cigarette smoke-exposed mice using EPR/NMR co-imaging

    NASA Astrophysics Data System (ADS)

    Caia, George L.; Efimova, Olga V.; Velayutham, Murugesan; El-Mahdy, Mohamed A.; Abdelghany, Tamer M.; Kesselring, Eric; Petryakov, Sergey; Sun, Ziqi; Samouilov, Alexandre; Zweier, Jay L.

    2012-03-01

    In vivo mapping of alterations in redox status is important for understanding organ specific pathology and disease. While electron paramagnetic resonance imaging (EPRI) enables spatial mapping of free radicals, it does not provide anatomic visualization of the body. Proton MRI is well suited to provide anatomical visualization. We applied EPR/NMR co-imaging instrumentation to map and monitor the redox state of living mice under normal or oxidative stress conditions induced by secondhand cigarette smoke (SHS) exposure. A hybrid co-imaging instrument, EPRI (1.2 GHz)/proton MRI (16.18 MHz), suitable for whole-body co-imaging of mice was utilized with common magnet and gradients along with dual EPR/NMR resonators that enable co-imaging without sample movement. The metabolism of the nitroxide probe, 3-carbamoyl-proxyl (3-CP), was used to map the redox state of control and SHS-exposed mice. Co-imaging allowed precise 3D mapping of radical distribution and reduction in major organs such as the heart, lungs, liver, bladder and kidneys. Reductive metabolism was markedly decreased in SHS-exposed mice and EPR/NMR co-imaging allowed quantitative assessment of this throughout the body. Thus, in vivo EPR/NMR co-imaging enables in vivo organ specific mapping of free radical metabolism and redox stress and the alterations that occur in the pathogenesis of disease.

  10. A double species 23Na and 87Rb Bose-Einstein condensate with tunable miscibility via an interspecies Feshbach resonance

    NASA Astrophysics Data System (ADS)

    Wang, Fudong; Li, Xiaoke; Xiong, Dezhi; Wang, Dajun

    2016-01-01

    We have realized a dual-species Bose-Einstein condensate (BEC) of 23Na and 87Rb atoms and observed its immiscibility. Because of the favorable background intra- and inter-species scattering lengths, stable condensates can be obtained via efficient evaporative cooling and sympathetic cooling without the need for fine tuning of the interactions. Our system thus provides a clean platform for studying inter-species interactions-driven effects in superfluid mixtures. With a Feshbach resonance, we have successfully created double BECs with largely tunable inter-species interactions and studied the miscible-immiscible phase transition.

  11. Sodium 3D COncentration MApping (COMA 3D) using 23Na and proton MRI

    NASA Astrophysics Data System (ADS)

    Truong, Milton L.; Harrington, Michael G.; Schepkin, Victor D.; Chekmenev, Eduard Y.

    2014-10-01

    Functional changes of sodium 3D MRI signals were converted into millimolar concentration changes using an open-source fully automated MATLAB toolbox. These concentration changes are visualized via 3D sodium concentration maps, and they are overlaid over conventional 3D proton images to provide high-resolution co-registration for easy correlation of functional changes to anatomical regions. Nearly 5000/h concentration maps were generated on a personal computer (ca. 2012) using 21.1 T 3D sodium MRI brain images of live rats with spatial resolution of 0.8 × 0.8 × 0.8 mm3 and imaging matrices of 60 × 60 × 60. The produced concentration maps allowed for non-invasive quantitative measurement of in vivo sodium concentration in the normal rat brain as a functional response to migraine-like conditions. The presented work can also be applied to sodium-associated changes in migraine, cancer, and other metabolic abnormalities that can be sensed by molecular imaging. The MATLAB toolbox allows for automated image analysis of the 3D images acquired on the Bruker platform and can be extended to other imaging platforms. The resulting images are presented in a form of series of 2D slices in all three dimensions in native MATLAB and PDF formats. The following is provided: (a) MATLAB source code for image processing, (b) the detailed processing procedures, (c) description of the code and all sub-routines, (d) example data sets of initial and processed data. The toolbox can be downloaded at: http://www.vuiis.vanderbilt.edu/~truongm/COMA3D/.

  12. Sodium 3D COncentration MApping (COMA 3D) using (23)Na and proton MRI.

    PubMed

    Truong, Milton L; Harrington, Michael G; Schepkin, Victor D; Chekmenev, Eduard Y

    2014-10-01

    Functional changes of sodium 3D MRI signals were converted into millimolar concentration changes using an open-source fully automated MATLAB toolbox. These concentration changes are visualized via 3D sodium concentration maps, and they are overlaid over conventional 3D proton images to provide high-resolution co-registration for easy correlation of functional changes to anatomical regions. Nearly 5000/h concentration maps were generated on a personal computer (ca. 2012) using 21.1T 3D sodium MRI brain images of live rats with spatial resolution of 0.8×0.8×0.8 mm(3) and imaging matrices of 60×60×60. The produced concentration maps allowed for non-invasive quantitative measurement of in vivo sodium concentration in the normal rat brain as a functional response to migraine-like conditions. The presented work can also be applied to sodium-associated changes in migraine, cancer, and other metabolic abnormalities that can be sensed by molecular imaging. The MATLAB toolbox allows for automated image analysis of the 3D images acquired on the Bruker platform and can be extended to other imaging platforms. The resulting images are presented in a form of series of 2D slices in all three dimensions in native MATLAB and PDF formats. The following is provided: (a) MATLAB source code for image processing, (b) the detailed processing procedures, (c) description of the code and all sub-routines, (d) example data sets of initial and processed data. The toolbox can be downloaded at: http://www.vuiis.vanderbilt.edu/~truongm/COMA3D/. PMID:25261742

  13. Sodium 3D COncentration MApping (COMA 3D) Using 23Na and Proton MRI

    PubMed Central

    Truong, Milton L.; Harrington, Michael G.; Schepkin, Victor D.; Chekmenev, Eduard Y.

    2014-01-01

    Functional changes of sodium 3D MRI signals were converted into millimolar concentration changes using an open-source fully automated MATLAB toolbox. These concentration changes are visualized via 3D sodium concentration maps, and they are overlaid over conventional 3D proton images to provide high-resolution co-registration for easy correlation of functional changes to anatomical regions. Nearly 5000/hour concentration maps were generated on a personal computer (ca. 2012) using 21.1 T 3D sodium MRI brain images of live rats with spatial resolution of 0.8×0.8×0.8 mm3 and imaging matrices of 60×60×60. The produced concentration maps allowed for non-invasive quantitative measurement of in vivo sodium concentration in the normal rat brain as a functional response to migraine-like conditions. The presented work can also be applied to sodium-associated changes in migraine, cancer, and other metabolic abnormalities that can be sensed by molecular imaging. The MATLAB toolbox allows for automated image analysis of the 3D images acquired on the Bruker platform and can be extended to other imaging platforms. The resulting images are presented in a form of series of 2D slices in all three dimensions in native MATLAB and PDF formats. The following is provided: (a) MATLAB source code for image processing, (b) the detailed processing procedures, (c) description of the code and all sub-routines, (d) example data sets of initial and processed data. The toolbox can be downloaded at: http://www.vuiis.vanderbilt.edu/~truongm/COMA3D/ PMID:25261742

  14. Measurement of 23Na(α,p)26Mg at Energies Relevant to 26Al Production in Massive Stars.

    PubMed

    Tomlinson, J R; Fallis, J; Laird, A M; Fox, S P; Akers, C; Alcorta, M; Bentley, M A; Christian, G; Davids, B; Davinson, T; Fulton, B R; Galinski, N; Rojas, A; Ruiz, C; de Séréville, N; Shen, M; Shotter, A C

    2015-07-31

    26Al is an important radioisotope in astrophysics that provides evidence of ongoing nucleosynthesis in the Galaxy. The 23Na(α, p)26Mg reaction has been identified by a sensitivity study as being one of the most important reactions for the production of 26Al in the convective C/Ne burning shell of massive stars. Owing to large uncertainties in previous experimental data, model calculations are used for the reaction rate of 23Na(α, p)26Mg in this sensitivity study. Current experimental data suggest a reaction rate a factor of ∼40 higher than model calculations. However, a new measurement of this reaction cross section has been made in inverse kinematics in the energy range E(c.m.)=1.28-3.15  MeV at TRIUMF, and found to be in reasonable agreement with the model calculation. A new reaction rate is calculated and tight constraints on the uncertainty in the production of 26Al, due to this reaction, are determined. PMID:26274415

  15. Diagnostics of a charge breeder electron cyclotron resonance ion source helium plasma with the injection of 23Na1+ ions

    NASA Astrophysics Data System (ADS)

    Tarvainen, O.; Koivisto, H.; Galatà, A.; Angot, J.; Lamy, T.; Thuillier, T.; Delahaye, P.; Maunoury, L.; Mascali, D.; Neri, L.

    2016-05-01

    This work describes the utilization of an injected 23Na1+ ion beam as a diagnostics of the helium plasma of a charge breeder electron cyclotron resonance ion source. The obtained data allows estimating the upper limit for the ion-ion collision mean-free path of the incident sodium ions, the lower limit of ion-ion collision frequencies for all charge states of the sodium ions and the lower limit of the helium plasma density. The ion-ion collision frequencies of high charge state ions are shown to be at least on the order of 1-10 MHz and the plasma density is estimated to be on the order of 1011 cm-3 or higher. The experimental results are compared to simulations of the 23Na1+ capture into the helium plasma. The results indicate that the lower breeding efficiency of light ions in comparison to heavier elements is probably due to different capture efficiencies in which the in-flight ionization of the incident 1 + ions plays a vital role.

  16. Time-efficient interleaved human (23)Na and (1)H data acquisition at 7 T.

    PubMed

    de Bruin, Paul W; Koken, Peter; Versluis, Maarten J; Aussenhofer, Sebastian A; Meulenbelt, Ingrid; Börnert, Peter; Webb, Andrew G

    2015-10-01

    The aim of this study was to implement and evaluate a flexible and time-efficient interleaved imaging approach for the acquisition of proton and sodium images of the human knee at 7 T within a clinically relevant timescale. A flexible software framework was established which allowed the interleaving of multiple, different, fully specific absorption ratio (SAR)-validated scans. The system was able to switch between these different scans at flexible time points. The practical example presented consists of interleaved proton (Dixon imaging and T2* mapping) and sodium (mapping the sodium content and fluid-suppressed component separately) sequences with the key idea to perform proton MRI whilst the sodium nuclei relax towards thermal equilibrium, and vice versa. Comparisons were made between these four scans being acquired sequentially in the normal mode of scanner operation and those acquired in an interleaved fashion. Images acquired in the interleaved mode were very similar to those acquired in sequential scans with no image artifacts produced by the slight intra-sequence variation in steady-state magnetization. A reduction in scanning time of almost a factor of two was established using the interleaved scans, allowing such a protocol to be completed within 30 min. Phantom experiments and in vivo scans performed in healthy volunteers and in one patient proved the basic feasibility of this approach. This approach for the interleaving of multiple proton and sodium scans, each with different contrasts, is an efficient method for the design of new practical clinical protocols for sodium MRI. PMID:26269329

  17. Longitudinal NMR parameter measurements of Japanese pear fruit during the growing process using a mobile magnetic resonance imaging system

    NASA Astrophysics Data System (ADS)

    Geya, Yuto; Kimura, Takeshi; Fujisaki, Hirotaka; Terada, Yasuhiko; Kose, Katsumi; Haishi, Tomoyuki; Gemma, Hiroshi; Sekozawa, Yoshihiko

    2013-01-01

    Longitudinal nuclear magnetic resonance (NMR) parameter measurements of Japanese pear fruit (Pyrus pyrifolia Nakai, Kosui) were performed using an electrically mobile magnetic resonance imaging (MRI) system with a 0.2 T and 16 cm gap permanent magnet. To measure the relaxation times and apparent diffusion coefficients of the pear fruit in relation to their weight, seven pear fruits were harvested almost every week during the cell enlargement period and measured in a research orchard. To evaluate the in situ relaxation times, six pear fruits were longitudinally measured for about two months during the same period. The measurements for the harvested samples showed good agreement with the in situ measurements. From the measurements of the harvested samples, it is clear that the relaxation rates of the pear fruits linearly change with the inverse of the linear dimension of the fruits, demonstrating that the relaxation mechanism is a surface relaxation. We therefore conclude that the mobile MRI system is a useful device for measuring the NMR parameters of outdoor living plants.

  18. Development of an antibody-based, modular biosensor for 129Xe NMR molecular imaging of cells at nanomolar concentrations

    PubMed Central

    Rose, Honor M.; Witte, Christopher; Rossella, Federica; Klippel, Stefan; Freund, Christian; Schröder, Leif

    2014-01-01

    Magnetic resonance imaging (MRI) is seriously limited when aiming for visualization of targeted contrast agents. Images are reconstructed from the weak diamagnetic properties of the sample and require an abundant molecule like water as the reporter. Micromolar to millimolar concentrations of conventional contrast agents are needed to generate image contrast, thus excluding many molecular markers as potential targets. To address this limitation, we developed and characterized a functional xenon NMR biosensor that can identify a specific cell surface marker by targeted 129Xe MRI. Cells expressing the cell surface protein CD14 can be spatially distinguished from control cells with incorporation of as little as 20 nM of the xenon MRI readout unit, cryptophane-A. Cryptophane-A serves as a chemical host for hyperpolarized nuclei and facilitates the sensitivity enhancement achieved by xenon MRI. Although this paper describes the application of a CD14-specific biosensor, the construct has been designed in a versatile, modular fashion. This allows for quick and easy adaptation of the biosensor to any cell surface target for which there is a specific antibody. In addition, the modular design facilitates the creation of a multifunctional probe that incorporates readout modules for different detection methods, such as fluorescence, to complement the primary MRI readout. This modular antibody-based approach not only offers a practical technique with which to screen targets, but one which can be readily applied as the xenon MRI field moves closer to molecular imaging applications in vivo. PMID:25071165

  19. Development of an antibody-based, modular biosensor for 129Xe NMR molecular imaging of cells at nanomolar concentrations.

    PubMed

    Rose, Honor M; Witte, Christopher; Rossella, Federica; Klippel, Stefan; Freund, Christian; Schröder, Leif

    2014-08-12

    Magnetic resonance imaging (MRI) is seriously limited when aiming for visualization of targeted contrast agents. Images are reconstructed from the weak diamagnetic properties of the sample and require an abundant molecule like water as the reporter. Micromolar to millimolar concentrations of conventional contrast agents are needed to generate image contrast, thus excluding many molecular markers as potential targets. To address this limitation, we developed and characterized a functional xenon NMR biosensor that can identify a specific cell surface marker by targeted (129)Xe MRI. Cells expressing the cell surface protein CD14 can be spatially distinguished from control cells with incorporation of as little as 20 nM of the xenon MRI readout unit, cryptophane-A. Cryptophane-A serves as a chemical host for hyperpolarized nuclei and facilitates the sensitivity enhancement achieved by xenon MRI. Although this paper describes the application of a CD14-specific biosensor, the construct has been designed in a versatile, modular fashion. This allows for quick and easy adaptation of the biosensor to any cell surface target for which there is a specific antibody. In addition, the modular design facilitates the creation of a multifunctional probe that incorporates readout modules for different detection methods, such as fluorescence, to complement the primary MRI readout. This modular antibody-based approach not only offers a practical technique with which to screen targets, but one which can be readily applied as the xenon MRI field moves closer to molecular imaging applications in vivo. PMID:25071165

  20. On the suppression of background signals originating from NMR hardware components. Application to zero echo time imaging and relaxation time analysis.

    PubMed

    Dreher, Wolfgang; Bardenhagen, Ingo; Huang, Li; Bäumer, Marcus

    2016-04-01

    Modern NMR imaging systems used for biomedical research are equipped with B0 gradient systems with strong maximum gradient strength and short switching time enabling (1)H NMR measurements of samples with very short transverse relaxation times. However, background signal originating from non-optimized RF coils may hamper experiments with ultrashort delays between RF excitation and signal reception. We demonstrate that two simple means, outer volume suppression and the use of shaped B0 fields produced by higher-order shim coils, allow a considerable suppression of disturbing background signals. Thus, the quality of NMR images acquired at ultrashort or zero echo time is improved and systematic errors in quantitative data evaluation are avoided. Fields of application comprise MRI with ultrashort echo time or relaxation time analysis, for both biomedical research and characterizing porous media filled with liquids or gases. PMID:26597837

  1. 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.

  2. The Effect of Inhomogeneous Sample Susceptibility on Measured Diffusion Anisotropy Using NMR Imaging

    NASA Astrophysics Data System (ADS)

    Trudeau, J. D.; Dixon, W. T.; Hawkins, J.

    1995-07-01

    Water diffusion measurements in white matter of freshly excised pig spinal cord and in parenchyma of fresh celery (excluding the fibers along the edge of the stalk) were performed using NMR at 200 MHz. In white matter of pig spinal cord, the measured diffusion coefficient is anisotropic and independent of sample orientation with respect to the magnetic field, In celery parenchyma, diffusion is isotropic and independent of orientation in the magnetic field when using a diffusion sequence that gives results independent of self-induced magnetic-held gradients. However, when the standard diffusion pulse sequence that gives results dependent upon self-induced magnetic-field gradients is used, diffusion in celery appears isotropic when the stalk is oriented parallel to the magnetic field but anisotropic when oriented perpendicular. Susceptibility variations leading to anisotropic self-induced magnetic-field gradients approximately 3 kHz/cm in magnitude when the celery is oriented perpendicular to the magnetic field can explain this apparent anisotropic diffusion. A study of the apparent diffusion coefficient (ADC) in celery as a function of diffusion times ranging from 8 to 22 ms indicates that the motion is at most only slightly restricted. Therefore, although the effect is not seen in all types of samples, one must be aware that self-induced gradients may affect the ADC and may cause isotropic diffusion to appear anisotropic. In addition, NMR experiments that change diffusion-sensitizing gradient timings to study restricted diffusion change the effects of the self-induced gradients as well as the effect of barriers on the ADC, complicating interpretation.

  3. Fast production of large {sup 23}Na Bose-Einstein condensates in an optically plugged magnetic quadrupole trap

    SciTech Connect

    Heo, Myoung-Sun; Choi, Jae-yoon; Shin, Yong-il

    2011-01-15

    We demonstrate a fast production of large {sup 23}Na Bose-Einstein condensates in an optically plugged magnetic quadrupole trap. A single global minimum of the trapping potential is generated by slightly displacing the plug beam from the center of the quadrupole field. With a dark magneto-optical trap and a simple rf evaporation, our system produces a condensate with N{approx_equal}10{sup 7} atoms every 17 s. The Majorana loss rates and the resultant heating rates for various temperatures are measured with and without plugging. The average energy of a spin-flipped atom is almost linearly proportional to temperature and determined to be about 60% of the average energy of a trapped atom. We present a numerical study of the evaporation dynamics in a plugged linear trap.

  4. Neutron scattering differential cross sections for 23Na from 1.5 to 4.5 MeV

    NASA Astrophysics Data System (ADS)

    Vanhoy, J. R.; Hicks, S. F.; Chakraborty, A.; Champine, B. R.; Combs, B. M.; Crider, B. P.; Kersting, L. J.; Kumar, A.; Lueck, C. J.; Liu, S. H.; McDonough, P. J.; McEllistrem, M. T.; Peters, E. E.; Prados-Estévez, F. M.; Sidwell, L. C.; Sigillito, A. J.; Watts, D. W.; Yates, S. W.

    2015-07-01

    Measurements of neutron elastic and inelastic scattering cross sections from 23Na have been performed for sixteen incident neutron energies between 1.5 and 4.5 MeV. These measurements were complemented by γ-ray excitation functions using the (n ,n‧ γ) reaction to include excited levels not resolved in the neutron detection measurements. The time-of-flight (TOF) technique was employed for background reduction in both neutron and γ-ray measurements and for energy determination in neutron detection measurements. Previous reaction model evaluations relied primarily on neutron total cross sections and four (n, n0) and (n, n1) angular distributions in the 5 to 9 MeV range. The inclusion of more inelastic channels and measurements at lower incident neutron energies provide additional information on direct couplings between elastic and inelastic scattering as a function of angular momentum transfer. Reaction model calculations examining collective direct-coupling and compound absorption components were performed.

  5. Chemically selective NMR imaging of a 3-component (solid-solid-liquid) sedimenting system.

    PubMed

    Beyea, Steven D; Altobelli, Stephen A; Mondy, Lisa A

    2003-04-01

    A novel magnetic resonance imaging (MRI) technique which resolves the separate components of the evolving vertical concentration profiles of 3-component non-colloidal suspensions is described. This method exploits the sensitivity of MRI to chemical differences between the three phases to directly image the fluid phase and one of the solid phases, with the third phase obtained by subtraction. 19F spin-echo imaging of a polytetrafluoroethylene (PTFE) oil was interlaced with 1H SPRITE imaging of low-density polyethylene (LDPE) particles. The third phase was comprised of borosilicate glass spheres, which were not visible while imaging the PTFE or LDPE phases. The method is demonstrated by performing measurements on 2-phase materials containing only the floating (LDPE) particles, with the results contrasted to the experimental behaviour of the individual phases in the full 3-phase system. All experiments were performed using nearly monodisperse particles, with initial suspension volume fractions, phi(i), of 0.1. PMID:12713970

  6. Stray-field NMR diffusion q-space diffraction imaging of monodisperse coarsening foams.

    PubMed

    Smith, Kieron; Burbidge, Adam; Apperley, David; Hodgkinson, Paul; Markwell, Fraser A; Topgaard, Daniel; Hughes, Eric

    2016-08-15

    The technique of stray field diffusion NMR is adapted to study the diffusion properties of water in monodisperse wet foams. We show for the first time, that the technique is capable of observing q-space diffusion diffraction peaks in monodisperse aqueous foams with initial bubble sizes in the range of 50-85μm. The position of the peak maximum can be correlated simply to the bubble size in the foam leading to a technique that can investigate the stability of the foam over time. The diffusion technique, together with supplementary spin-spin relaxation analysis of the diffusion data is used to follow the stability and coarsening behaviour of monodisperse foams with a water fraction range between 0.24 and 0.33. The monodisperse foams remain stable for a period of hours in terms of the initial bubble size. The duration of this stable period correlates to the initial size of the bubbles. Eventually the bubbles begin to coarsen and this is observed in changes in the position of the diffusion diffraction maxima. PMID:27179175

  7. Direct measurement of the (23)Na(α,p)(26)Mg reaction cross section at energies relevant for the production of galactic (26)Al.

    PubMed

    Almaraz-Calderon, S; Bertone, P F; Alcorta, M; Albers, M; Deibel, C M; Hoffman, C R; Jiang, C L; Marley, S T; Rehm, K E; Ugalde, C

    2014-04-18

    The 1809-keV γ ray from the decay of (26)Al(g) is an important target for γ-ray astronomy. In the convective C/Ne burning shell of massive presupernova stars, the (23)Na(α,p)(26)Mg reaction directly influences the production of (26)Al. We have performed a direct measurement of the (23)Na(α,p)(26)Mg reaction cross section at the appropriate astrophysically important energies. The stellar rate calculated in the present work is larger than the recommended rate by nearly a factor of 40 and could strongly affect the production of (26)Al in massive stars. PMID:24785033

  8. Imaging of the B1 distribution and background signal in a MAS NMR probehead using inhomogeneous B0 and B1 fields.

    PubMed

    Odedra, Smita; Wimperis, Stephen

    2013-06-01

    Several widely used methods for suppressing the "background" signal in (1)H magic angle spinning (MAS) NMR spectroscopy are based on the assumption of a significant difference between the B1 radiofrequency field experienced by the sample (within the MAS rotor) and that felt by static components of the probehead (where the background signal is believed to originate). In this work, a two-dimensional correlation experiment employing inhomogeneous B0 and B1 fields is used to image the B1 distribution in a MAS NMR probehead. The experiment, which can be performed on any spectrometer, allows the distribution of the B1 field to be measured and also correlated with the spatial location of the NMR signal within the probehead. The method can also readily be combined with various "depth pulse" techniques for background suppression, allowing their performances to be more rigorously evaluated. PMID:23644349

  9. Integration of biaxial planar gradient coils and an RF microcoil for NMR flow imaging

    NASA Astrophysics Data System (ADS)

    Goloshevsky, A. G.; Walton, J. H.; Shutov, M. V.; de Ropp, J. S.; Collins, S. D.; McCarthy, M. J.

    2005-02-01

    A package of two planar gradient coils combined with an RF coil was microfabricated for low-field MRI measurements of velocity flow profiles. The package generates orthogonal gradients in the radial and velocity encoding directions for standard flow imaging experiments. A commercial 0.6 T superconductive magnet was used to test coil performance. For comparison flow imaging was also performed using a commercial set of gradient coils. Velocity profiles were obtained for several volumetric flow rates of water in tubes with inner diameters of 1.02 mm and 1.4 mm. Velocity resolution was 0.13 mm s-1, comparable to that achieved with commercial gradient coils. The quality of the velocity profile was sufficient for viscosity calculations, and thus permits future utilization of this coil package in the design of a portable MRI viscometer.

  10. Clinical NMR imaging of the brain in children: normal and neurologic disease

    SciTech Connect

    Johnson, M.A,; Pennock, J.M.; Bydder, G.M.; Steiner, R.E.; Thomas, D.J.; Hayward, R.; Bryant, D.R.T.; Payne, J.A.; Levene, M.I.; Whitelaw, A.; Dubowitz, L.M.S.; Dubowitz, V.

    1983-11-01

    The results of initial clinical nuclear magnetic resonance imaging of the brain in eight normal and 52 children with a wide variety of neurologic diseases were reviewed. The high level of gray-white matter contrast available with inversion-recovery sequences provided a basis for visualizing normal myelination as well as delays or deficits in this process. The appearances seen in cases of parenchymal hemorrhage, cerebral infarction, and proencephalic cysts are described. Ventricular enlargement was readily identified and marginal edema was demonstrated with spin-echo sequences. Abnormalities were seen in cerebral palsy, congenital malformations, Hallervorden-Spatz disease, aminoaciduria, and meningitis. Space-occupying lesions were identified by virtue of their increased relaxation times and mass effects. Nuclear magnetic resonance imaging has considerable potential in pediatric neuroradiologic practice, in some conditions supplying information not available by computed tomography or sonography.

  11. Multiphase imaging of gas flow in a nanoporous material usingremote detection NMR

    SciTech Connect

    Harel, Elad; Granwehr, Josef; Seeley, Juliette A.; Pines, Alex

    2005-10-03

    Pore structure and connectivity determine how microstructured materials perform in applications such as catalysis, fluid storage and transport, filtering, or as reactors. We report a model study on silica aerogel using a recently introduced time-of-flight (TOF) magnetic resonance imaging technique to characterize the flow field and elucidate the effects of heterogeneities in the pore structure on gas flow and dispersion with Xe-129 as the gas-phase sensor. The observed chemical shift allows the separate visualization of unrestricted xenon and xenon confined in the pores of the aerogel. The asymmetrical nature of the dispersion pattern alludes to the existence of a stationary and a flow regime in the aerogel. An exchange time constant is determined to characterize the gas transfer between them. As a general methodology, this technique provides new insights into the dynamics of flow in porous media where multiple phases or chemical species may be present.

  12. Software and hardware integration of a microprogrammable state machine for NMR imaging.

    PubMed

    Stewart, B K; Pratt, R G; Thomas, S R; Dieckman, S L; Ridgway, T H

    1991-01-01

    We have integrated a commercially available microprogrammable state machine (Tecmag PULSkit) for use as a magnetic resonance pulse programmer. Providing the capability for active research environment imaging protocols, it features timing resolution of 100 nsec, ten 16-bit loop counters, and individually addressable look-up tables. This integration involved hardware and software integration with a VAX 11/750 at several levels. Hardware: Each of the three gradient channels employs three digital-to-analog converters (DACs). An 8-bit, 4-quadrant, multiplying DAC generates the gradient waveform shape. A 12-bit DAC generates the multiplying DAC scaling voltage, controlling gradient amplitude and sign. A third 12-bit DAC produces a gradient offset (shim) voltage. An eddy current compensation network is present for each gradient channel. Software: The software design philosophy was to create a flexible interface (interactive window environment), while not constraining complex manipulation of the hardware (direct use of the pulse-sequence compiler primitives and microprogramming). The software levels include (a) pulse-sequence microprogramming, (b) pulse-sequence compiler, (c) interactive parameter specification, and (d) canned pulse-sequence microcode library. PMID:1779734

  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. Experimental determination of the {sup 26}Al(n,{alpha}){sup 23}Na reaction cross section and calculation of the Maxwellian averaged cross section at stellar temperatures

    SciTech Connect

    Smet, L. de; Wagemans, C.; Wagemans, J.; Heyse, J.; Gils, J. van

    2007-10-15

    The {sup 26}Al(n,{alpha}){sup 23}Na reaction cross section has been studied at the linear accelerator GELINA of the Institute for Reference Materials and Measurements in Geel, Belgium, and has been determined up to a neutron energy of about 100 keV using the time-of-flight technique. Six resonances could be observed in this energy region, whereas before only one had been identified experimentally. For four of them, resonance parameters such as resonance energy, total width, area, and spin of the state could be determined. From the obtained {sup 26}Al(n,{alpha}){sup 23}Na cross section data, Maxwellian averaged cross section (MACS) values were calculated by numerical integration. Since neutron induced reactions are among the major destruction mechanisms of {sup 26}Al in our Galaxy, these new MACS values contribute to a better understanding of the observed {sup 26}Al abundance.

  15. The 12C(12C,α)20Ne and 12C(12C,p)23Na reactions at the Gamow peak via the Trojan Horse Method

    NASA Astrophysics Data System (ADS)

    Tumino, A.; Spitaleri, C.; Cherubini, S.; Guardo, L.; Gulino, M.; Indelicato, I.; La Cognata, M.; Lamia, L.; Pizzone, R. G.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Spartá, R.

    2016-05-01

    A measurement of the 12C(14N,α20Ne)2H and 12C(14N,p23Na)2Hreactions has been performed at a 14N beam energy of 30.0 MeV. The experiment aims to explore the extent to which contributing 24Mg excited states can be populated in the quasi-free reaction off the deuteron in 14N. In particular, the 24Mg excitation region explored in the measurement plays a key role in stellar carbon burning whose cross section is commonly determined by extrapolating high-energy fusion data. From preliminary results, α and proton channels are clearly identified. In particular, ground and first excited states of 20Ne and 23Na play a major role.

  16. Measurement of the Absolute Elastic and Inelastic Differential Neutron Cross Sections for 23Na Between 2 and 4 MeV

    NASA Astrophysics Data System (ADS)

    Kumar, A.; Chakraborty, A.; Crider, B. P.; McEllistrem, M. T.; Peters, E. E.; Prados-Estévez, F. M.; Yates, S. W.; Hicks, S. F.; Kersting, L. J.; Luke, C. J.; McDonough, P. J.; Sigillito, A. J.; Vanhoy, J. R.

    2013-03-01

    Elastic and inelastic neutron scattering angular distributions have been measured from 23Na for incident neutron energies between 2 and 4 MeV at the University of Kentucky using neutron time-of-flight techniques. The cross sections obtained are important for applications in nuclear reactor development and other areas, and they are an energy region in which existing data are very sparse. Absolute cross sections were obtained by normalizing Na angular distributions to the well-known np cross sections.

  17. Application of NMR spectroscopy and multidimensional imaging to the gelcasting process and in-situ real-time monitoring of cross-linking polyacrylamide gels

    SciTech Connect

    Ahuja, S.; Dieckman, S.L.; Gopalsami, N.

    1995-04-01

    In the gelcasting process, a slurry of ceramic powder in a solution of organic monomers is cast in a mold. The process is different from injection molding in that it separates mold-filling from setting during conversion of the ceramic slurry to a formed green part. In this work, NMR spectroscopy and imaging have been conducted for in-situ monitoring of the gelation process and for mapping the polymerization. {sup 1}H nuclear magnetic resonance spectra have been obtained during polymerization of a premix of soluble reactive methacrylamide (monomer) and N, N`-methylene bisacrylamide (cross-linking molecules). The premix was polymerized by adding ammonium persulfate (initiator) and tetramethyl-ethylene-diamine (accelerator) to form long-chain, cross-linked polymers. The time-varying spin-lattice relaxation times T{sub 1} during polymerization have been studied at 25 and 35{degrees}C, and the variation of spectra and T{sub 1} with respect to extent of polymerization has been determined. To verify homogeneous polymerization, multidimensional NMR imaging was utilized for in-situ monitoring of the process. The intensities from the images are modeled and the correspondence shows a direct extraction of T{sub 1} data from the images.

  18. Multinuclear Solid-State NMR Investigation of Hexaniobate and Hexatantalate Compounds.

    PubMed

    Deblonde, Gauthier J-P; Coelho-Diogo, Cristina; Chagnes, Alexandre; Cote, Gérard; Smith, Mark E; Hanna, John V; Iuga, Dinu; Bonhomme, Christian

    2016-06-20

    This work determines the potential of solid-state NMR techniques to probe proton, alkali, and niobium environments in Lindqvist salts. Na7HNb6O19·15H2O (1), K8Nb6O19·16H2O (2), and Na8Ta6O19·24.5H2O (3) have been studied by solid-state static and magic angle spinning (MAS) NMR at high and ultrahigh magnetic field (16.4 and 19.9 T). (1)H MAS NMR was found to be a convenient and straightforward tool to discriminate between protonated and nonprotonated clusters AxH8-xM6O19·nH2O (A = alkali ion; M = Nb, Ta). (93)Nb MAS NMR studies at different fields and MAS rotation frequencies have been performed on 1. For the first time, the contributions of NbO5Oμ2H sites were clearly distinguished from those assigned to NbO6 sites in the hexaniobate cluster. The strong broadening of the resonances obtained under MAS was interpreted by combining chemical shift anisotropy (CSA) with quadrupolar effects and by using extensive fitting of the line shapes. In order to obtain the highest accuracy for all NMR parameters (CSA and quadrupolar), (93)Nb WURST QCPMG spectra in the static mode were recorded at 16.4 T for sample 1. The (93)Nb NMR spectra were interpreted in connection with the XRD data available in the literature (i.e., fractional occupancies of the NbO5Oμ2H sites). 1D (23)Na MAS and 2D (23)Na 3QMAS NMR studies of 1 revealed several distinct sodium sites. The multiplicity of the sites was again compared to structural details previously obtained by single-crystal X-ray diffraction (XRD) studies. The (23)Na MAS NMR study of 3 confirmed the presence of a much larger distribution of sodium sites in accordance with the 10 sodium sites predicted by XRD. Finally, the effect of Nb/Ta substitutions in 1 was also probed by multinuclear MAS NMR ((1)H, (23)Na, and (93)Nb). PMID:27245403

  19. 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

  20. 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.

  1. A 23Na magic angle spinning nuclear magnetic resonance, XANES, and high-temperature X-ray diffraction study of NaUO3, Na4UO5, and Na2U2O7.

    PubMed

    Smith, A L; Raison, P E; Martel, L; Charpentier, T; Farnan, I; Prieur, D; Hennig, C; Scheinost, A C; Konings, R J M; Cheetham, A K

    2014-01-01

    The valence state of uranium has been confirmed for the three sodium uranates NaU(V)O3/[Rn](5f(1)), Na4U(VI)O5/[Rn](5f(0)), and Na2U(VI)2O7/[Rn](5f(0)), using X-ray absorption near-edge structure (XANES) spectroscopy. Solid-state (23)Na magic angle spinning nuclear magnetic resonance (MAS NMR) measurements have been performed for the first time, yielding chemical shifts at -29.1 (NaUO3), 15.1 (Na4UO5), and -14.1 and -19 ppm (Na1 8-fold coordinated and Na2 7-fold coordinated in Na2U2O7), respectively. The [Rn]5f(1) electronic structure of uranium in NaUO3 causes a paramagnetic shift in comparison to Na4UO5 and Na2U2O7, where the electronic structure is [Rn]5f(0). A (23)Na multi quantum magic angle spinning (MQMAS) study on Na2U2O7 has confirmed a monoclinic rather than rhombohedral structure with evidence for two distinct Na sites. DFT calculations of the NMR parameters on the nonmagnetic compounds Na4UO5 and Na2U2O7 have permitted the differentiation between the two Na sites of the Na2U2O7 structure. The linear thermal expansion coefficients of all three compounds have been determined using high-temperature X-ray diffraction: αa = 22.7 × 10(-6) K(-1), αb = 12.9 × 10(-6) K(-1), αc = 16.2 × 10(-6) K(-1), and αvol = 52.8 × 10(-6) K(-1) for NaUO3 in the range 298-1273 K; αa = 37.1 × 10(-6) K(-1), αc = 6.2 × 10(-6) K(-1), and αvol = 81.8 × 10(-6) K(-1) for Na4UO5 in the range 298-1073 K; αa = 6.7 × 10(-6) K(-1), αb = 14.4 × 10(-6) K(-1), αc = 26.8 × 10(-6) K(-1), αβ = -7.8 × 10(-6) K(-1), and αvol = -217.6 × 10(-6) K(-1) for Na2U2O7 in the range 298-573 K. The α to β phase transition reported for the last compound above about 600 K was not observed in the present studies, either by high-temperature X-ray diffraction or by differential scanning calorimetry. PMID:24350659

  2. Status of the direct measurements of 18O(p,γ)19F and 23Na(p,γ)24Mg cross sections at astrophysical energies at LUNA

    NASA Astrophysics Data System (ADS)

    Boeltzig, A.; Pantaleo, F. R.; Best, A.; Imbriani, G.; Junker, M.

    2016-04-01

    18O(p, γ)19F and 23Na(p,γ)24Mg are reactions of astrophysical interest for example in AGB star scenarios. The rates of both reactions are potentially influenced by low-energy resonances for whose strengths either exist only values with large uncertainties, upper limits or even contradictory claims. Measurements at the Laboratory for Underground Nuclear Astrophysics (LUNA) aim at a direct observation of these low-energy resonances, and additional cross section measurements to aid a more precise determination of the reaction rates in astrophysical scenarios. We report the experimental setup and the status of the ongoing measurements of the two reactions at LUNA.

  3. Atomic masses of {sup 6}Li,{sup 23}Na,{sup 39,41}K,{sup 85,87}Rb, and {sup 133}Cs

    SciTech Connect

    Mount, Brianna J.; Redshaw, Matthew; Myers, Edmund G.

    2010-10-15

    The atomic masses of the alkali-metal isotopes {sup 6}Li,{sup 23}Na,{sup 39,41}K,{sup 85,87}Rb, and {sup 133}Cs have been obtained from measurements of cyclotron frequency ratios of pairs of ions simultaneously trapped in a Penning trap. The results, with one standard deviation uncertainty, are: M({sup 6}Li)=6.015 122 887 4(16)u,M({sup 23}Na)=22.989769 282 8(26)u,M({sup 39}K)=38.963 706 485 6(52)u,M({sup 41}K)=40.961 825 257 4(48)u,M({sup 85}Rb)=84.911 789739(9)u,M({sup 87}Rb)=86.909 180 535(10)u, and M({sup 133}Cs)=132.905 451 963(13)u. Our mass of {sup 6}Li yields an improved neutron separation energy for {sup 7}Li of 7251.1014(45) keV.

  4. Strengths of the resonances at 436, 479, 639, 661, and 1279 keV in the 22Ne(p ,γ ) 23Na reaction

    NASA Astrophysics Data System (ADS)

    Depalo, Rosanna; Cavanna, Francesca; Ferraro, Federico; Slemer, Alessandra; Al-Abdullah, Tariq; Akhmadaliev, Shavkat; Anders, Michael; Bemmerer, Daniel; Elekes, Zoltán; Mattei, Giovanni; Reinicke, Stefan; Schmidt, Konrad; Scian, Carlo; Wagner, Louis

    2015-10-01

    The 22Ne(p ,γ )23Na reaction is included in the neon-sodium cycle of hydrogen burning. A number of narrow resonances in the Gamow window dominate the thermonuclear reaction rate. Several resonance strengths are only poorly known. As a result, the 22Ne(p ,γ )23Na thermonuclear reaction rate is the most uncertain rate of the cycle. Here, a new experimental study of the strengths of the resonances at 436, 479, 639, 661, and 1279 keV proton beam energy is reported. The data have been obtained using a tantalum target implanted with 22Ne. The strengths ω γ of the resonances at 436, 639, and 661 keV have been determined with a relative approach, using the 479- and 1279-keV resonances for normalization. Subsequently, the ratio of resonance strengths of the 479- and 1279-keV resonances were determined, improving the precision of these two standards. The new data are consistent with, but more precise than, the literature with the exception of the resonance at 661 keV, which is found to be less intense by one order of magnitude. In addition, improved branching ratios have been determined for the gamma decay of the resonances at 436, 479, and 639 keV.

  5. 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.

  6. 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.

  7. Double rotation NMR studies of zeolites and aluminophosphate molecular sieves

    SciTech Connect

    Jelinek, R. |

    1993-07-01

    Goal is to study the organization and structures of guest atoms and molecules and their reactions on internal surfaces within pores of zeolites and aluminophosphate molecular sieves. {sup 27}Al and {sup 23}Na double rotation NMR (DOR) is used since it removes the anisotropic broadening in NMR spectra of quadrupolar nuclei, thus increasing resolution. This work concentrates on probing aluminum framework atoms in aluminophosphate molecular sieves and sodium extra framework cations in porous aluminosilicates. In aluminophosphates, ordering and electronic environments of the framework {sup 27}Al nuclei are modified upon adsorption of water molecules within the channels; a relation is sought between the sieve channel topology and the organization of adsorbed water, as well as the interaction between the Al nuclei and the water molecules. Extra framework Na{sup +} cations are directly involved in adsorption processes and reactions in zeolite cavities.

  8. Spin-labeled gel for the production of radical-free dynamic nuclear polarization enhanced molecules for NMR spectroscopy and imaging

    NASA Astrophysics Data System (ADS)

    McCarney, Evan R.; Han, Songi

    2008-02-01

    Dynamic nuclear polarization (DNP) has recently received much attention as a viable approach to enhance the sensitivity of nuclear magnetic resonance (NMR) spectroscopy and the contrast of magnetic resonance imaging (MRI), where the significantly higher electron spin polarization of stable radicals is transferred to nuclear spins. In order to apply DNP-enhanced NMR and MRI signal to biological and in vivo systems, it is crucial to obtain highly polarized solution samples at ambient temperatures. As stable radicals are employed as the source for the DNP polarization transfer, it is also crucial that the highly polarized sample lacks residual radical concentration because the polarized molecules will be introduced to a biological system that will be sensitive to the presence of radicals. We developed an agarose-based porous media that is covalently spin-labeled with stable radicals. The loading of solvent accessible radical is sufficiently high and their mobility approximates that in solution, which ensures high efficiency for Overhauser mechanism induced DNP without physically releasing any measurable radical into the solution. Under ambient conditions at 0.35 T magnetic field, we measure the DNP enhancement efficiency of 1H signal of stagnant and continuously flowing water utilizing immobilized stable nitroxide radicals that contain two or three ESR hyperfine splitting lines and compare them to the performance of freely dissolved radicals.

  9. Using "On/Off" (19)F NMR/Magnetic Resonance Imaging Signals to Sense Tyrosine Kinase/Phosphatase Activity in Vitro and in Cell Lysates.

    PubMed

    Zheng, Zhen; Sun, Hongbin; Hu, Chen; Li, Gongyu; Liu, Xiaomei; Chen, Peiyao; Cui, Yusi; Liu, Jing; Wang, Junfeng; Liang, Gaolin

    2016-03-15

    Tyrosine kinase and phosphatase are two important, antagonistic enzymes in organisms. Development of noninvasive approach for sensing their activity with high spatial and temporal resolution remains challenging. Herein, we rationally designed a hydrogelator Nap-Phe-Phe(CF3)-Glu-Tyr-Ile-OH (1a) whose supramolecular hydrogel (i.e., Gel 1a) can be subjected to tyrosine kinase-directed disassembly, and its phosphate precursor Nap-Phe-Phe(CF3)-Glu-Tyr(H2PO3)-Ile-OH (1b), which can be subjected to alkaline phosphatase (ALP)-instructed self-assembly to form supramolecular hydrogel Gel 1b, respectively. Mechanic properties and internal fibrous networks of the hydrogels were characterized with rheology and cryo transmission electron microscopy (cryo-TEM). Disassembly/self-assembly of their corresponding supramolecular hydrogels conferring respective "On/Off" (19)F NMR/MRI signals were employed to sense the activity of these two important enzymes in vitro and in cell lysates for the first time. We anticipate that our new (19)F NMR/magnetic resonance imaging (MRI) method would facilitate pharmaceutical researchers to screen new inhibitors for these two enzymes without steric hindrance. PMID:26901415

  10. Applications of high resolution NMR to geochemistry: crystalline, glass, and molten silicates

    SciTech Connect

    Schneider, E.

    1985-11-01

    The nuclear spin interactions and the associated quantum mechanical dynamics which are present in solid state NMR are introduced. A brief overview of aluminosilicate structure is presented and crystalline structure is then reviewed, with emphasis on the contributions made by /sup 29/Si NMR spectroscopy. The local structure of glass aluminosilicates as observed by NMR, is presented with analysis of the information content of /sup 29/Si spectra. A high-temperature (to 1300/sup 0/C) NMR spectroscopic investigation of the local environment and dynamics of molecular motion in molten aluminosilicates is described. A comparison is made of silicate liquid, glass, and crystalline local structure. The atomic and molecular motions present in a melt are investigated through relaxation time (T/sub 1/ and T/sub 2/) measurements as a function of composition and temperature for /sup 23/Na and /sup 29/Si.

  11. 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

    the connectivity of the pore system. Examples are given for T1-T2 correlation of some soil samples (Haber-Pohlmeier et al. 2010). Third, relaxometric information forms the basis of understanding magnetic resonance imaging (MRI) results. The general difficulty of imaging in soils are the inherent fast T2 relaxation times due to i) the small pore sizes, ii) presence of paramagnetic ions in the solid matrix, and iii) diffusion in internal gradients. The last point is important, since echo times can not set shorter than about 1ms for imaging purposes. The way out is either the usage of low fields for imaging in soils or special ultra-short pulse sequences, which do not create echoes. In this presentation we will give examples on conventional imaging of macropore fluxes in soil cores (Haber-Pohlmeier et al. 2010), and the combination with relaxometric imaging, as well as the advantages and drawbacks of low-field and ultra-fast pulse imaging. Also first results on the imaging of soil columns measured by SIP in Project A3 are given. Haber-Pohlmeier, S., S. Stapf, et al. (2010). "Waterflow Monitored by Tracer Transport in Natural Porous Media Using MRI." Vadose Zone J.: submitted. Haber-Pohlmeier, S., S. Stapf, et al. (2010). "Relaxation in a Natural soil: Comparison of Relaxometric Imaging, T1 - T2 Correlation and Fast-Field Cycling NMR." The Open Magnetic Resonance Journal: in print. Pohlmeier, A., S. Haber-Pohlmeier, et al. (2009). "A Fast Field Cycling NMR Relaxometry Study of Natural Soils." Vadose Zone J. 8: 735-742. Stingaciu, L. R., A. Pohlmeier, et al. (2009). "Characterization of unsaturated porous media by high-field and low-field NMR relaxometry." Water Resources Research 45: W08412

  12. Arterial metabolism as studied in vitro by NMR: preliminary results in normotensive and hypertensive aortas.

    PubMed

    Carlier, P G; Grandjean, J; Michel, P; D'Orio, V; Rorive, G L

    1985-12-01

    Arterial tissue has been analysed by 31P-, 13C-, 23Na- and 1H-NMR spectroscopy. Rabbit thoracic aortas were mounted on a system with perfusate circulation and studied in basal conditions. Phosphorus spectra remained stable for hours and showed low levels of phosphocreatine (PCr) compared to skeletal, cardiac or even to nonvascular smooth muscle. Significant levels of sugar-phosphates (SP), phosphodiesters (PDE) were detected, as well as occasionnally a peak in the diphosphodiester region. Experiments with phosphate-free perfusate demonstrated a very low level of intracellular inorganic phosphate. As expected from previous data, free ADP levels in tonic arterial tissue were found much higher than in any other muscle. Addition of norepinephrine into the perfusate induced transient decrease in ATP and PCr levels, associated with an increased production of phosphorylated intermediates. At the early stage of renovascular hypertension, aortic energetic pattern was characterized by an increased ADP/ATP ratio. Natural abundant 13C spectra were recorded from dog aortic fragments and showed mainly resonances attributed to fatty components. After addition of a shift-reagent, dysprosium tripolyphosphate, 23Na-NMR allowed separation of intra- and extracellular Na of perfused rabbits aortas. Proton NMR of lyophilized aortic fragments revealed several peaks originating from biologically relevant molecules, lactate, creatine, taurine... These preliminary data demonstrate the feasability of multinuclear NMR spectroscopy of vascular tissue and are suggestive of the potential of the method when it will be combined with monitoring of functional parameters. PMID:2424380

  13. Theoretical evaluation of the reaction rates for {sup 26}Al(n,p){sup 26}Mg and {sup 26}Al(n,{alpha}){sup 23}Na

    SciTech Connect

    Oginni, B. M.; Iliadis, C.; Champagne, A. E.

    2011-02-15

    The reactions that destroy {sup 26}Al in massive stars have significance in a number of astrophysical contexts. We evaluate the reaction rates of {sup 26}Al(n,p){sup 26}Mg and {sup 26}Al(n,{alpha}){sup 23}Na using cross sections obtained from the codes empire and talys. These have been compared to the published rates obtained from the non-smoker code and to some experimental data. We show that the results obtained from empire and talys are comparable to those from non-smoker. We also show how the theoretical results vary with respect to changes in the input parameters. Finally, we present recommended rates for these reactions using the available experimental data and our new theoretical results.

  14. Measurement of the Absolute Elastic and Inelastic Differential Neutron Cross Sections for 23Na between 2 and 4 MeV

    NASA Astrophysics Data System (ADS)

    Kumar, Ajay; McEllistrem, M. T.; Crider, B. P.; Peters, E. E.; Prados-Estevez, F. M.; Chakraborty, A.; Yates, S. W.; Sigillito, A.; McDonough, P. J.; Kersting, L. J.; Luke, C. J.; Hicks, S. F.; Vanhoy, J. R.

    2011-10-01

    Elastic and inelastic neutron scattering angular distributions for 23Na sample were measured at the University of Kentucky using the time-of-flight (ToF) technique, between 2 and 4 MeV incident neutron energies.Normalization of yields into scattering cross sections was accomplished by comparison of Na yields to the yields obtained from hydrogen in polyethylene samples via the well-known n-p scattering cross sections.The 3H(p,n) differential cross sections are used to determine the energy-dependent efficiency of the main detector. Because the efficiency of this detector appears as a ratio in the comparison of scattered yields from different samples, the absolute values of the 3H(p,n) cross sections are not critical, but their energy dependence is. This work is supported by the U.S. DOE contract no. DE-AC07-051D14517.

  15. 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

  16. Magic-angle spinning solid-state multinuclear NMR on low-field instrumentation

    NASA Astrophysics Data System (ADS)

    Sørensen, Morten K.; Bakharev, Oleg; Jensen, Ole; Jakobsen, Hans J.; Skibsted, Jørgen; Nielsen, Niels Chr.

    2014-01-01

    Mobile and cost-effective NMR spectroscopy exploiting low-field permanent magnets is a field of tremendous development with obvious applications for arrayed large scale analysis, field work, and industrial screening. So far such demonstrations have concentrated on relaxation measurements and lately high-resolution liquid-state NMR applications. With high-resolution solid-state NMR spectroscopy being increasingly important in a broad variety of applications, we here introduce low-field magic-angle spinning (MAS) solid-state multinuclear NMR based on a commercial ACT 0.45 T 62 mm bore Halbach magnet along with a homebuilt FPGA digital NMR console, amplifiers, and a modified standard 45 mm wide MAS probe for 7 mm rotors. To illustrate the performance of the instrument and address cases where the low magnetic field may offer complementarity to high-field NMR experiments, we demonstrate applications for 23Na MAS NMR with enhanced second-order quadrupolar coupling effects and 31P MAS NMR where reduced influence from chemical shift anisotropy at low field may facilitate determination of heteronuclear dipole-dipole couplings.

  17. RF interference suppression in a cardiac synchronization system operating in a high magnetic field NMR imaging system

    SciTech Connect

    Damji, A.A.; Snyder, R.E.; Ellinger, D.C.; Witkowski, F.X.; Allen, P.S.

    1988-11-01

    An electrocardiographic (ECG) unit suitable for cardiac-synchronized nuclear magnetic resonance imaging in high magnetic fields is presented. The unit includes lossy transmission lines as ECG leads in order to suppress radio frequency (RF) interference in the electrocardiogram. The unit's immunity to RF interference is demonstrated.

  18. NMR quadrupolar system described as Bose-Einstein-condensate-like system

    SciTech Connect

    Auccaise, R.; Oliveira, I. S.; Sarthour, R. S.; Teles, J.; Bonagamba, T. J.; Azevedo, E. R. de

    2009-04-14

    This paper presents a description of nuclear magnetic resonance (NMR) of quadrupolar systems using the Holstein-Primakoff (HP) formalism and its analogy with a Bose-Einstein condensate (BEC) system. Two nuclear spin systems constituted of quadrupolar nuclei I=3/2 ({sup 23}Na) and I=7/2 ({sup 133}Cs) in lyotropic liquid crystals were used for experimental demonstrations. Specifically, we derived the conditions necessary for accomplishing the analogy, executed the proper experiments, and compared with quantum mechanical prediction for a Bose system. The NMR description in the HP representation could be applied in the future as a workbench for BEC-like systems, where the statistical properties may be obtained using the intermediate statistic, first established by Gentile. The description can be applied for any quadrupolar systems, including new developed solid-state NMR GaAS nanodevices.

  19. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  1. Multinuclear high-resolution NMR study of compounds from the ternary system NaF-CaF2-AlF3: from determination to modeling of NMR parameters.

    PubMed

    Martineau, C; Body, M; Legein, C; Silly, G; Buzaré, J-Y; Fayon, F

    2006-12-11

    27Al and 23Na NMR satellite transition spectroscopy and 3Q magic-angle-spinning spectra are recorded for three compounds from the ternary NaF-CaF2-AlF3 system. The quadrupolar frequency nuQ, asymmetry parameter etaQ, and isotropic chemical shift deltaiso are extracted from the spectrum reconstructions for five aluminum and four sodium sites. The quadrupolar parameters are calculated using the LAPW-based ab initio code WIEN2k. It is necessary to perform a structure optimization of all compounds to ensure a fine agreement between experimental and calculated parameters. By a comparison of experimental and calculated values, an attribution of all of the 27Al and 23Na NMR lines to the crystallographic sites is achieved. High-speed 19F NMR MAS spectra are recorded and reconstructed for the same compounds, leading to the determination of 18 isotropic chemical shifts. The superposition model developed by Bureau et al. is used, allowing a bijective assignment of the 19F NMR lines to the crystallographic sites. PMID:17140229

  2. Probing the calcium and sodium local environment in bones and teeth using multinuclear solid state NMR and X-ray absorption spectroscopy.

    PubMed

    Laurencin, Danielle; Wong, Alan; Chrzanowski, Wojciech; Knowles, Jonathan C; Qiu, Dong; Pickup, David M; Newport, Robert J; Gan, Zhehong; Duer, Melinda J; Smith, Mark E

    2010-02-01

    Despite the numerous studies of bone mineral, there are still many questions regarding the exact structure and composition of the mineral phase, and how the mineral crystals become organised with respect to each other and the collagen matrix. Bone mineral is commonly formulated as hydroxyapatite, albeit with numerous substitutions, and has previously been studied by (31)P and (1)H NMR, which has given considerable insight into the complexity of the mineral structure. However, to date, there has been no report of an NMR investigation of the other major component of bone mineral, calcium, nor of common minority cations like sodium. Here, direct analysis of the local environment of calcium in two biological apatites, equine bone (HB) and bovine tooth (CT), was carried out using both (43)Ca solid state NMR and Ca K-edge X-ray absorption spectroscopy, revealing important structural information about the calcium coordination shell. The (43)Ca delta(iso) in HB and CT is found to correlate with the average Ca-O bond distance measured by Ca K-edge EXAFS, and the (43)Ca NMR linewidths show that there is a greater distribution in chemical bonding around calcium in HB and CT, compared to synthetic apatites. In the case of sodium, (23)Na MAS NMR, high resolution 3Q-MAS NMR, as well as (23)Na{(31)P} REDOR and (1)H{(23)Na} R(3)-HMQC correlation experiments give the first direct evidence that some sodium is located inside the apatite phase in HB and CT, but with a greater distribution of environments compared to a synthetic sodium substituted apatite (Na-HA). PMID:20094673

  3. Hepatocarcinogenesis tumor grading correlated with in vivo image-guided {sup 1}H-NMR spectroscopy in a rat model

    SciTech Connect

    Towner, Rheal A. . E-mail: Rheal-Towner@omrf.ouhsc.edu; Foley, Lesley M.; Painter, Dorothy M.

    2005-09-01

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

  4. 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

  5. Fabrication of homogeneously cross-linked, functional alginate microcapsules validated by NMR-, CLSM- and AFM-imaging.

    PubMed

    Zimmermann, H; Hillgärtner, M; Manz, B; Feilen, P; Brunnenmeier, F; Leinfelder, U; Weber, M; Cramer, H; Schneider, S; Hendrich, C; Volke, F; Zimmermann, U

    2003-05-01

    Cross-linked alginate microcapsules of sufficient mechanical strength can immunoisolate cells for the long-term treatment of hormone and other deficiency diseases in human beings. However, gelation of alginate by external Ba(2+) (or other divalent cations) produces non-homogeneous cross-linking of the polymeric mannuronic (M) and guluronic (G) acid chains. The stability of such microcapsules is rather limited. Here, we show that homogeneous cross-linking can be achieved by injecting BaCl(2) crystals into alginate droplets before they come into contact with external BaCl(2). The high effectiveness of this crystal gun method is demonstrated by confocal laser scanning microscopy and by advanced nuclear magnetic resonance imaging. Both techniques gave clear-cut evidence that homogeneous cross-linkage throughout the microcapsule is only obtained with simultaneous internal and external gelation. Atomic force microscopy showed a very smooth surface topography for microcapsules made by the crystal gun method, provided that excess Ba(2+) ions were removed immediately after gelation. In vitro experiments showed greatly suppressed swelling for crystal gun microcapsules. Even alginate extracted from Lessonia nigrescens (highly biocompatible) yielded microcapsules with long-term mechanical stability not hitherto possible. Encapsulation of rat islets, human monoclonal antibodies secreting hybridoma cells and murine mesenchymal stem cells transfected with cDNA encoding for bone morphogenetic protein (BMP-4) revealed that injection of BaCl(2) crystals has no adverse side effects on cell viability and function. However, the release of low-molecular weight factors (such as insulin) may be delayed when using alginate concentrations in the usual range. PMID:12628829

  6. NMR imaging estimates of muscle volume and intramuscular fat infiltration in the thigh: variations with muscle, gender, and age.

    PubMed

    Hogrel, Jean-Yves; Barnouin, Yoann; Azzabou, Noura; Butler-Browne, Gillian; Voit, Thomas; Moraux, Amélie; Leroux, Gaëlle; Behin, Anthony; McPhee, Jamie S; Carlier, Pierre G

    2015-06-01

    Muscle mass is particularly relevant to follow during aging, owing to its link with physical performance and autonomy. The objectives of this work were to assess muscle volume (MV) and intramuscular fat (IMF) for all the muscles of the thigh in a large population of young and elderly healthy individuals using magnetic resonance imaging (MRI) to test the effect of gender and age on MV and IMF and to determine the best representative slice for the estimation of MV and IMF. The study enrolled 105 healthy young (range 20-30 years) and older (range 70-80 years) subjects. MRI scans were acquired along the femur length using a three-dimension three-point Dixon proton density-weighted gradient echo sequence. MV and IMF were estimated from all the slices. The effects of age and gender on MV and IMF were assessed. Predictive equations for MV and IMF were established using a single slice at various femur levels for each muscle in order to reduce the analysis process. MV was decreased with aging in both genders, particularly in the quadriceps femoris. IMF was largely increased with aging in men and, to a lesser extent, in women. Percentages of MV decrease and IMF increase with aging varied according to the muscle. Predictive equations to predict MV and IMF from single slices are provided and were validated. This study is the first one to provide muscle volume and intramuscular fat infiltration in all the muscles of the thigh in a large population of young and elderly healthy subjects. PMID:26040416

  7. 7Li double quantum filtered NMR and multinuclear relaxation rates of clay suspensions: the effect of clay concentration and nonionic surfactants

    PubMed

    Grandjean; Robert

    1999-05-01

    7Li double quantum NMR spectra were used to investigate ordering process of synthetic Li+-saponites dispersed in water. Synthetic clays suspended in aqueous solutions of poly(ethylene glycol) monoalkyl ethers were also studied by 7Li, 23Na, and 13C NMR techniques. The strongest surfactant-Li+-saponite interaction occurs with the lowest charged clay. Laponite interacts more strongly with organic molecules than does a similarly charged saponite. The number of oxyethylene units rather than the chain length seems to govern the solid-surfactant interaction. Copyright 1999 Academic Press. PMID:10329224

  8. A multinuclear static NMR study of geopolymerisation

    SciTech Connect

    Favier, Aurélie; Habert, Guillaume; Roussel, Nicolas; D'Espinose de Lacaillerie, Jean-Baptiste

    2015-09-15

    Geopolymers are inorganic binders obtained by alkali activation of aluminosilicates. While the structure of geopolymers is now well understood, the details of the geopolymerisation reaction and their impact on the rheology of the paste remain uncertain. In this work, we follow the elastic properties of a paste made with metakaolin and sodium silicate solution. After the first sharp increase of elastic modulus occurring a few hundred of seconds after mixing and related to the heterogeneous formation of an alumina–silicate gel with a molar ratio Si/Al < 4 located at the grains boundaries, we focus on the progressive increase in elastic modulus on a period of few hours during the setting of the geopolymer. In this study, we combine the study of rheological properties of the paste with {sup 23}Na, {sup 27}Al and {sup 29}Si static NMR measurement in order to better understand the origin of this second increase in elastic modulus. Our results show that, after a few hours, Al and Na evolution in the liquid phase are concomitant. This suggests the precipitation of an aluminosilicate phase where Al is in tetrahedral position and Na compensates the charge. Furthermore, Si speciation confirms this result and allows us to identify the precipitation of a product, which has a chemical composition close to the final composition of geopolymer. This study provides strong evidence for a heterogeneous formation of an aluminosilicate glass directly from the first gel and the silicate solution without the need for a reorganisation of Gel 1 into Gel 2.

  9. In situ microscopic studies on the structures and phase behaviors of SF/PEG films using solid-state NMR and Raman imaging.

    PubMed

    Chen, Congheng; Yao, Ting; Tu, Sidong; Xu, Weijie; Han, Yi; Zhou, Ping

    2016-06-28

    In order to overcome the drawbacks of silk fibroin (SF)-based materials, SF has been blended with some polymers. Before using the blend material, understanding of the structures and phase behaviors of the blend is thought to be essential. In this study, solid-state (13)C CP-MAS NMR and Raman imaging techniques were used to study the structures and phase behaviors of blends of SF with polyethylene glycol (PEG) at a molecular weight that varied from 2 to 20 kDa and a blend ratio of SF/PEG from 95/5 to 70/30 (w/w%) at the molecular and microscopic levels. It is found that the conformational transition of SF to the β-sheet increased as the PEG content increased, while the amount of the formed β-sheet conformers was decreased as the PEG molecular weight increased for a given content. It is also observed that SF was incompatible with PEG to some extent. The phase separation into "sea" and "island" domains took place in the SF/PEG blend films. SF was dominantly present in the "sea" domain, while PEG in the "island" domains. The conformation of SF in the interface between SF and PEG was changed to the β-sheet, while that in the protein-rich domain remained in the random coil and/or helix conformation. These observations suggest that the specifically expected materials, for example, the silk-based microspheres or scaffold materials can be manufactured by controlling the molecular weight and content of PEG in the blend system. PMID:27255417

  10. NMR study of new ruthenates with high magnetic ordering

    NASA Astrophysics Data System (ADS)

    Paulose, P. L.; Chakrabarty, Tanmoy

    The Ru based compounds, Ca3LiRuO6 and Ca3NaRuO6 show unusually high magnetic ordering temperature. Extended super exchange model is invoked to explain the magnetic behavior in the isostructural compound Ca3LiOsO6. We have carried out NMR investigation on these two Ru-based compounds. Ca3LiRuO6 is a weak ferromagnet with a magnetic ordering temperature (TC) of 115 K which is explored by the temperature dependence of 7Li NMR line shift, line-width and spin-lattice relaxation rate (1/T1) . Above TC, a broad maximum is observed in the evolution of line-width of the spectra. We speculate that this feature might be attributed to some low-dimensional magnetic behavior. Contrastingly, Ca3NaRuO6 with similar structure and local geometry of the Ru5+ ions is a conventional antiferromagnet with a transition temperature of 90 K. The temperature dependence of 23Na NMR line shift and 1/T1 is studied across magnetic transition in Ca3NaRuO6. The temperature variation of line-width is found to be different compared to Ca3LiRuO6. In both these systems, 1/T1 decreases significantly below ordering temperature, characteristic of many antiferromagnetic systems.

  11. 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.

  12. 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...

  13. 19F-decoupling of half-integer spin quadrupolar nuclei in solid-state NMR: application of frequency-swept decoupling methods.

    PubMed

    Chandran, C Vinod; Hempel, Günter; Bräuniger, Thomas

    2011-09-01

    In solid-state NMR studies of minerals and ion conductors, quadrupolar nuclei like (7)Li, (23)Na or (133)Cs are frequently situated in close proximity to fluorine, so that application of (19)F decoupling is beneficial for spectral resolution. Here, we compare the decoupling efficiency of various multi-pulse decoupling sequences by acquiring (19)F-decoupled (23)Na-NMR spectra of cryolite (Na(3)AlF(6)). Whereas the MAS spectrum is only marginally affected by application of (19)F decoupling, the 3Q-filtered (23)Na signal is very sensitive to it, as the de-phasing caused by the dipolar interaction between sodium and fluorine is three-fold magnified. Experimentally, we find that at moderate MAS speeds, the decoupling efficiencies of the frequency-swept decoupling schemes SW(f)-TPPM and SW(f)-SPINAL are significantly better than the conventional TPPM and SPINAL sequences. The frequency-swept sequences are therefore the methods of choice for efficient decoupling of quadrupolar nuclei with half-integer spin from fluorine. PMID:21856132

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. Structural implications of water dissolution in haplogranitic glasses from NMR spectroscopy: influence of total water content and mixed alkali effect

    NASA Astrophysics Data System (ADS)

    Schmidt, B. C.; Riemer, T.; Kohn, S. C.; Holtz, F.; Dupree, R.

    2001-09-01

    To study the effects of total water content and alkali substitution on the structure of aluminosilicate glasses, two series of glasses belonging to the ternary system Quartz (Qz)-Albite (Ab)-Orthoclase (Or) were synthesized and investigated with nuclear magnetic resonance (NMR) spectroscopy. Series I consisted of seven glasses with normative composition Ab 39Or 32Qz 29 (AOQ) and water contents ranging from 0 to 6 wt%. Series II consisted of dry and hydrous glasses (˜2.0 wt% H 2O) with five compositions along the join Qz 37Ab 63-Qz 34Or 66 (AQ-OQ) varying the alkali content (Na/K) at constant Si/Al ratio. All glasses were investigated with 1H, 23Na, 27Al and 29Si magic angle spinning (MAS) NMR. 29Si MAS spectra of AOQ glasses showed no change upon hydration, suggesting little variation of the Si environments although the large linewidth of the 29Si signal may hide the presence of some Si Q 3-OH. The isotropic chemical shift (δ iso) of 27Al showed no change upon hydration, regardless of the amount of dissolved water. The 27Al mean quadrupolar coupling constant (C q) decreased with increasing water content, indicating a general increase of symmetry of the charge distribution around Al, which suggests the absence of significant amounts of Al Q 3-OH. Nonetheless, the evolution of C q upon hydration suggests a correlation with OH concentration in the quenched glass. The evolution of 23Na isotropic chemical shifts upon hydration appears to be correlated with total water content or with the concentration of dissolved H 2O molecules. In general, the NMR data are consistent with the water solubility model of Kohn et al. (1989), involving the exchange of charge balancing cations by protons. However, in addition to the presence of molecular water, 1H-NMR results showed at least two types of OH groups of which one may be related to Al-OH. Although the small intensity of this signal indicates that only a minor fraction of OH groups is present in this species, it demonstrates

  2. Decay Properties of {sup 266}Bh and {sup 262}Db Produced in the {sup 248}Cm+{sup 23}Na Reaction - Further Confirmation of the {sup 278}113 Decay Chain

    SciTech Connect

    Morita, K.; Morimoto, K.; Kaji, D.; Haba, H.; Ozeki, K.; Kudou, Y.; Yoneda, A.; Ichikawa, T.; Katori, K.; Yoshida, A.; Sato, N.; Sumita, T.; Fujimori, Y.; Tokanai, F.; Goto, S.; Ideguchi, E.; Kasamatsu, Y.; Koura, H.; Tsukada, K.; Komori, Y.

    2010-06-01

    Decay properties of an isotope {sup 266}Bh and its daughter nucleus {sup 262}Db produced by the {sup 248}Cm({sup 23}Na,5n) reaction were studied by using a gas-filled recoil separator coupled with a position-sensitive semiconductor detector. {sup 266}Bh was clearly identified from the correlation of the known nuclide, {sup 262}Db. The obtained decay properties of {sup 266}Bh and {sup 262}Db are consistent with those observed in the {sup 278}113 chain by RIKEN collaboration, which provided further confirmation of the discovery of {sup 278}113.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. Using NMR chemical shift imaging to monitor swelling and molecular transport in drug-loaded tablets of hydrophobically modified poly(acrylic acid): methodology and effects of polymer (in)solubility.

    PubMed

    Knöös, Patrik; Topgaard, Daniel; Wahlgren, Marie; Ulvenlund, Stefan; Piculell, Lennart

    2013-11-12

    A new technique has been developed using NMR chemical shift imaging (CSI) to monitor water penetration and molecular transport in initially dry polymer tablets that also contain small low-molecular weight compounds to be released from the tablets. Concentration profiles of components contained in the swelling tablets could be extracted via the intensities and chemical shift changes of peaks corresponding to protons of the components. The studied tablets contained hydrophobically modified poly(acrylic acid) (HMPAA) as the polymer component and griseofulvin and ethanol as hydrophobic and hydrophilic, respectively, low-molecular weight model compounds. The water solubility of HMPAA could be altered by titration with NaOH. In the pure acid form, HMPAA tablets only underwent a finite swelling until the maximum water content of the polymer-rich phase, as confirmed by independent phase studies, had been reached. By contrast, after partial neutralization with NaOH, the polyacid became fully miscible with water. The solubility of the polymer affected the water penetration, the polymer release, and the releases of both ethanol and griseofulvin. The detailed NMR CSI concentration profiles obtained highlighted the clear differences in the disintegration/dissolution/release behavior for the two types of tablet and provided insights into their molecular origin. The study illustrates the potential of the NMR CSI technique to give information of importance for the development of pharmaceutical tablets and, more broadly, for the general understanding of any operation that involves the immersion and ultimate disintegration of a dry polymer matrix in a solvent. PMID:24106807

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

    PubMed

    Paradowska, Katarzyna; Wawer, Iwona

    2014-05-01

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

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

    PubMed

    Edén, Mattias

    2010-05-01

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

  11. Off-resonance effects on 2D NMR nutation spectra of I = 3/2 quadrupolar nuclei in static samples.

    PubMed

    Xia, Y; Deng, F; Ye, C

    1995-12-01

    The off-resonance effects on 2D NMR nutation of I = 3/2 quadrupolar nuclei are demonstrated with perturbation theory and numerical calculation in static samples. The off-resonant (delta omega) rf field (omega 1) enlarges a nutation frequency and consequently increases the measurement range of nuclear quadrupolar interaction parameters. When omega e > omega Qmax, and arctg(omega 1/delta omega) = +/- 54.7 degrees (magic angle), the satellite lines (produced by coherence transfers) in a nutation spectrum are superimposed with the line of central transition, and hence the nutation spectrum is simplified and its sensitivity is enhanced. The nuclear quadrupolar interaction parameters of 23Na nuclei in Na omega molecular sieve are obtained using 2D NMR nutation. PMID:9053113

  12. Na/Ca Intermixing around Silicate and Phosphate Groups in Bioactive Phosphosilicate Glasses Revealed by Heteronuclear Solid-State NMR and Molecular Dynamics Simulations.

    PubMed

    Mathew, Renny; Stevensson, Baltzar; Edén, Mattias

    2015-04-30

    We characterize the intermixing of network-modifying Na(+)/Ca(2+) ions around the silicate (QSi(n)) and phosphate (QP(n)) tetrahedra in a series of 16 Na2O–CaO–SiO2–P2O5 glasses, whose P content and silicate network connectivity were varied independently. The set includes both bioactive and bioinactive compositions and also encompasses two soda-lime-silicate members devoid of P, as well as two CaO–SiO2 glasses and one Na2O–SiO2–P2O5 glass. The various Si/P↔Na/Ca contacts were probed by molecular dynamics (MD) simulations together with heteronuclear magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) experimentation utilizing (23)Na{(31)P} and (23)Na{(29)Si} REDOR, as well as (31)P{ (23)Na} and (29)Si{(23)Na} REAPDOR. We introduce an approach for quantifying the extent of Na(+)/Ca(2+) ordering around a given QP(n) or QSi(n) group, encoded by the preference factor 0⩽ PM ⩽ 1 conveying the relative weights of a random cation intermixing (PM = 0) and complete preference/ordering (PM = 1) for one of the species M, which represents either Na(+) or Ca(2+). The MD-derived preference factors reveal phosphate and silicate species surrounded by Na(+)/Ca(2+) ions intermixed nearly randomly (PM ≲ 0.15), except for the QSi(4) and QSi(1) groups, which manifest more significant cation ordering with preference for Na+ and Ca2+, respectively. The overall weak preferences are essentially independent of the Si and P contents of the glass, whereas PM primarily correlates with the total amount of network modifiers: as the latter is increased, the Na/Ca distribution around the {QP(0), QSi(1), QSi(2)} groups with preference for Ca2(+ )tend to randomize (i.e., PCa decreases), while the PNa-values grow slightly for the {QP(1), QSi(3), QSi(4)} species already preferring coordination of Na. The set of experimental preference factors {PCa} for the orthophosphate (QP(0)) groups extracted from (31)P{(23)Na} REAPDOR NMR-derived M2(P–Na) dipolar second moments agrees

  13. 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.

  14. On the microscopic fluctuations driving the NMR relaxation of quadrupolar ions in water

    SciTech Connect

    Carof, Antoine; Salanne, Mathieu; Rotenberg, Benjamin; Charpentier, Thibault

    2015-11-21

    Nuclear Magnetic Resonance (NMR) relaxation is sensitive to the local structure and dynamics around the probed nuclei. The Electric Field Gradient (EFG) is the key microscopic quantity to understand the NMR relaxation of quadrupolar ions, such as {sup 7}Li{sup +}, {sup 23}Na{sup +}, {sup 25}Mg{sup 2+}, {sup 35}Cl{sup −}, {sup 39}K{sup +}, or {sup 133}Cs{sup +}. Using molecular dynamics simulations, we investigate the statistical and dynamical properties of the EFG experienced by alkaline, alkaline Earth, and chloride ions at infinite dilution in water. Specifically, we analyze the effect of the ionic charge and size on the distribution of the EFG tensor and on the multi-step decay of its auto-correlation function. The main contribution to the NMR relaxation time arises from the slowest mode, with a characteristic time on the picosecond time scale. The first solvation shell of the ion plays a dominant role in the fluctuations of the EFG, all the more that the ion radius is small and its charge is large. We propose an analysis based on a simplified charge distribution around the ion, which demonstrates that the auto-correlation of the EFG, hence the NMR relaxation time, reflects primarily the collective translational motion of water molecules in the first solvation shell of the cations. Our findings provide a microscopic route to the quantitative interpretation of NMR relaxation measurements and open the way to the design of improved analytical theories for NMR relaxation for small ionic solutes, which should focus on water density fluctuations around the ion.

  15. Correlations between 11B NMR parameters and structural characters in borate and borosilicate minerals investigated by high-resolution MAS NMR and ab initio calculations

    NASA Astrophysics Data System (ADS)

    Zhou, Bing; Sun, Zhaohua; Yao, Yefeng; Pan, Yuanming

    2012-05-01

    Borates consisting of diverse fundamental building blocks (FBB) formed from complex polymerization of planar triangular [Bϕ3] groups and tetrahedral [Bϕ4] groups, where ϕ = O and OH, provide an excellent opportunity for investigation of correlations between the NMR parameters and local structures. However, previous studies suggested that the 11B NMR parameters in borates are insensitive to local structural environments other than the B coordination number, in contrast to those documented for 29Si, 23Na and 27Al in silicates, and no correlation between 11B chemical shifts and the sum of bond valences has been established for borate minerals with hydroxyl groups or molecular water in the structures. In this study, high-resolution NMR spectra have been acquired at the ultra high field of 21 T as well as at 14 T for selected borate and borosilicate minerals, and have been used to extract high-precision NMR parameters by using combined ab initio theoretical calculations and spectral simulations. These new NMR parameters reveal subtle correlations with various structural characters, especially the effects of the 11B chemical shifts from the bridging oxygen atom(s), site symmetry, symmetry of FBB, the sum of bond valences, as well as the next-nearest-neighbor cations and hydrogen bonding. Also, these results provide new insights into the shielding mechanism for 11B in borate and borosilicate minerals. In particular, this study demonstrates that the small variation in 11B chemical shifts can still be used to probe the local structural environments and that the established correlations can be used to investigate the structural details in borates and amorphous materials.

  16. ECG gated NMR-CT for cardiovascular diseases

    SciTech Connect

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

    1984-01-01

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

  17. Frozen State and Spin Liquid Physics in Na4 Ir3 O8 : An NMR Study

    NASA Astrophysics Data System (ADS)

    Shockley, A. C.; Bert, F.; Orain, J.-C.; Okamoto, Y.; Mendels, P.

    2015-07-01

    Na4Ir3 O8 is a unique case of a hyperkagome 3D corner sharing triangular lattice that can be decorated with quantum spins. It has spurred a lot of theoretical interest as a spin liquid candidate. We present a comprehensive set of NMR data taken on both the 23Na and 17O sites. We show that disordered magnetic freezing of all Ir sites sets in below Tf˜7 K , well below J =300 K , with a drastic slowing down of fluctuations to a static state revealed by our T1 measurements. Above typically 2 Tf, physical properties are relevant to the spin liquid state induced by this exotic geometry. While the shift data show that the susceptibility levels off below 80 K, 1 /T1 has little variation from 300 K to 2 Tf. We discuss the implication of our results in the context of published experimental and theoretical work.

  18. Feasibility of high-resolution one-dimensional relaxation imaging at low magnetic field using a single-sided NMR scanner applied to articular cartilage

    NASA Astrophysics Data System (ADS)

    Rössler, Erik; Mattea, Carlos; Stapf, Siegfried

    2015-02-01

    Low field Nuclear Magnetic Resonance increases the contrast of the longitudinal relaxation rate in many biological tissues; one prominent example is hyaline articular cartilage. In order to take advantage of this increased contrast and to profile the depth-dependent variations, high resolution parameter measurements are carried out which can be of critical importance in an early diagnosis of cartilage diseases such as osteoarthritis. However, the maximum achievable spatial resolution of parameter profiles is limited by factors such as sensor geometry, sample curvature, and diffusion limitation. In this work, we report on high-resolution single-sided NMR scanner measurements with a commercial device, and quantify these limitations. The highest achievable spatial resolution on the used profiler, and the lateral dimension of the sensitive volume were determined. Since articular cartilage samples are usually bent, we also focus on averaging effects inside the horizontally aligned sensitive volume and their impact on the relaxation profiles. Taking these critical parameters into consideration, depth-dependent relaxation time profiles with the maximum achievable vertical resolution of 20 μm are discussed, and are correlated with diffusion coefficient profiles in hyaline articular cartilage in order to reconstruct T2 maps from the diffusion-weighted CPMG decays of apparent relaxation rates.

  19. Whole body sodium MRI at 3T using an asymmetric birdcage resonator and short echo time sequence: first images of a male volunteer

    NASA Astrophysics Data System (ADS)

    Wetterling, Friedrich; Corteville, Dominique M.; Kalayciyan, Raffi; Rennings, Andreas; Konstandin, Simon; Nagel, Armin M.; Stark, Helmut; Schad, Lothar R.

    2012-07-01

    Sodium magnetic resonance imaging (23Na MRI) is a non-invasive technique which allows spatial resolution of the tissue sodium concentration (TSC) in the human body. TSC measurements could potentially serve to monitor early treatment success of chemotherapy on patients who suffer from whole body metastases. Yet, the acquisition of whole body sodium (23Na) images has been hampered so far by the lack of large resonators and the extremely low signal-to-noise ratio (SNR) achieved with existing resonator systems. In this study, a 23Na resonator was constructed for whole body 23Na MRI at 3T comprising of a 16-leg, asymmetrical birdcage structure with 34 cm height, 47.5 cm width and 50 cm length. The resonator was driven in quadrature mode and could be used either as a transceiver resonator or, since active decoupling was included, as a transmit-only resonator in conjunction with a receive-only (RO) surface resonator. The relative B1-field profile was simulated and measured on phantoms, and 3D whole body 23Na MRI data of a healthy male volunteer were acquired in five segments with a nominal isotropic resolution of (6 × 6 × 6) mm3 and a 10 min acquisition time per scan. The measured SNR values in the 23Na-MR images varied from 9 ± 2 in calf muscle, 15 ± 2 in brain tissue, 23 ± 2 in the prostate and up to 42 ± 5 in the vertebral discs. Arms, legs, knees and hands could also be resolved with applied resonator and short time-to-echo (TE) (0.5 ms) radial sequence. Up to fivefold SNR improvement was achieved through combining the birdcage with local RO surface coil. In conclusion, 23Na MRI of the entire human body provides sub-cm spatial resolution, which allows resolution of all major human body parts with a scan time of less than 60 min.

  20. Advanced NMR approaches in the characterization of coal

    SciTech Connect

    Maciel, G.E.

    1992-01-01

    A considerable effort in this project during the past few months has been focussed on the development of [sup 1]H and [sup 13]C NMR imaging techniques to yield spatially-resolved chemical shift (structure) information on coal. In order to yield the chemical shift information, a solid-state NMR imaging technique must include magic-angle spinning, so rotating gradient capabilities are indicated. A [sup 13]C MAS imaging probe and a [sup 1]H MAS imaging probe and the circuitry necessary for rotating gradients have been designed and constructed. The [sup 1]H system has already produced promising preliminary results, which are briefly described in this report.

  1. Novel electrolytes for use in new and improved batteries: An NMR study

    NASA Astrophysics Data System (ADS)

    Berman, Marc B.

    This thesis focuses on the use of nuclear magnetic resonance (NMR) spectroscopy in order to study materials for use as electrolytes in batteries. The details of four projects are described in this thesis as well as a brief theoretical background of NMR. Structural and dynamics properties were determined using several NMR techniques such as static, MAS, PFG diffusion, and relaxation to understand microscopic and macroscopic properties of the materials described within. Nuclei investigate were 1H, 2H, 7Li, 13C, 19F, 23Na, and 27Al. The first project focuses on an exciting new material to be used as a solid electrolyte membrane. T. The second project focuses on the dynamics of ionic liquid-solvent mixtures and their comparison to molecular dynamics computer simulations. The third project involves a solvent-free film containing NaTFSI salt mixed in to PEO for use in sodium-ion batteries. This final project focuses on a composite electrolyte consisting of a ceramic and solid: LiI:PEO:LiAlO2.

  2. 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.

  3. NMR analysis on microfluidic devices by remote detection

    SciTech Connect

    McDonnell, Erin E.; Han, SongI; Hilty, Christian; Pierce,Kimberly; Pines, Alexander

    2005-08-15

    We present a novel approach to perform high-sensitivity NMR imaging and spectroscopic analysis on microfluidic devices. The application of NMR, the most information rich spectroscopic technique, to microfluidic devices remains a challenge because the inherently low sensitivity of NMR is aggravated by small fluid volumes leading to low NMR signal, and geometric constraints resulting in poor efficiency for inductive detection. We address the latter by physically separating signal detection from encoding of information with remote detection. Thereby, we use a commercial imaging probe with sufficiently large diameter to encompass the entire device, enabling encoding of NMR information at any location on the chip. Because large-diameter coils are too insensitive for detection, we store the encoded information as longitudinal magnetization and flow it into the outlet capillary. There, we detect the signal with optimal sensitivity using a solenoidal microcoil, and reconstruct the information encoded in the fluid. We present a generally applicable design for a detection-only microcoil probe that can be inserted into the bore of a commercial imaging probe. Using hyperpolarized 129Xe gas, we show that this probe enables sensitive reconstruction of NMR spectroscopic information encoded by the large imaging probe while keeping the flexibility of a large coil.

  4. 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

  5. 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…

  6. 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

  7. Physical and Chemical Effects of Two-Phase Brine/Supercritical-CO2 Fluid Flow on Clastic Rocks: Real-Time Monitoring and NMR Imaging of Flow-Through Core Experiments

    NASA Astrophysics Data System (ADS)

    Shaw, C. A.; Vogt, S.; Maneval, J. E.; Brox, T.; Skidmore, M. L.; Codd, S. L.; Seymour, J. D.

    2010-12-01

    Sandstone core samples were challenged with a supercritical CO2-saturated brine mixture in a laboratory flow-through core reactor system over a range of temperatures and brine strengths. Cores of quartz arenite from the Berea formation were selected to represent ideal ‘clean’ sandstone These laboratory experiments potentially provide an analog for the acidification of pore fluids near the brine/CO2 interface during CO2 flooding of depleted clastic hydrocarbon reservoirs for carbon sequestration. Flow in the reactor was perpendicular to bedding. Initial experiments were run at 50°C and 100°C with brine concentrations of 1g/L and 10g/L (TDS) to test effects of different temperatures and brine compositions. Real-time monitoring of fluid pH and conductivity provided a measure of reaction rates. Introduction of supercritical CO2 into the brine-saturated cores initiated a reduction in pH accompanied by an increase in conductivity. NMR images of fresh cores were compared with images of challenged cores using a protocol for pixel-by-pixel comparison to determine the effects on bulk pore volume and geometry. Two types of imaging experiments were conducted: multi-slice spin echo and 3-D spin echo images. Multi-slice experiments had a slice thickness of 1.5 mm and an in-plane resolution of 0.27 mm x 0.27 mm, and 3-D experiments had a resolution of 0.47 mm x 0.55 mm x 0.55mm. Imaging results reflected the observed changes in the physical and chemical structure post-challenge. Two-dimensional relaxation correlation experiments were also conducted to probe the pore sizes, connectivity and fluid saturation of the rock cores before and after challenging. Chemical analyses and microscopic examination of the challenged cores will provide a better understanding of alteration in the cores and the changes in the volume, geometry and connectivity of pore space.

  8. 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.

  9. 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.

  10. 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